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Sample records for chalcophile elements hg

  1. Chalcophile elements Hg, Cd, Pb, As in Lake Umbozero, Murmansk Region, Russia

    DEFF Research Database (Denmark)

    Dauvalter, V.A.; Kashulin, N.A.; Lehto, J.; Jernström, Jussi

    2009-01-01

    affected by emissions and effluents from mining and metallurgical enterprises of the Murmansk Region, as well as air pollution of a global character. Surface and near-bottom maxima were found in the distributions of Pb and Cd in the water column. These two maxima appear to be associated with the cyclical...... growth of phytoplankton in surface water layers and with sedimentation of lifeless organisms and suspended particles in near-bottom layers. Average concentrations of Pb and Cd in the water column were more than the average value for water of lakes of the taiga zone. Pollution of Lake Umbozero led to......Investigations of Lake Umbozero, the second largest and the deepest lake of the Murmansk Region, were carried out to detect and define biogeochemical patterns of distribution of the chalcophile elements (Hg, Cd, Pb, As) in water, sediments and organs and tissues of whitefishes. Lake Umbozero is...

  2. Chalcophile elements Hg, Cd, Pb, As in Lake Umbozero, Murmansk Region, Russia

    DEFF Research Database (Denmark)

    Dauvalter, V.A.; Kashulin, N.A.; Lehto, J.;

    2009-01-01

    is affected by emissions and effluents from mining and metallurgical enterprises of the Murmansk Region, as well as air pollution of a global character. Surface and near-bottom maxima were found in the distributions of Pb and Cd in the water column. These two maxima appear to be associated with the cyclical...... growth of phytoplankton in surface water layers and with sedimentation of lifeless organisms and suspended particles in near-bottom layers. Average concentrations of Pb and Cd in the water column were more than the average value for water of lakes of the taiga zone. Pollution of Lake Umbozero led......Investigations of Lake Umbozero, the second largest and the deepest lake of the Murmansk Region, were carried out to detect and define biogeochemical patterns of distribution of the chalcophile elements (Hg, Cd, Pb, As) in water, sediments and organs and tissues of whitefishes. Lake Umbozero...

  3. Using chalcophile elements to constrain crustal contamination and xenolith-magma interaction in Cenozoic basalts of eastern China

    Science.gov (United States)

    Zeng, Gang; Huang, Xiao-Wen; Zhou, Mei-Fu; Chen, Li-Hui; Xu, Xi-Sheng

    2016-08-01

    Continental basalts have complicated petrogenetic processes, and their chemical compositions can be affected by multi-staged geological evolution. Compared to lithophile elements, chalcophile elements including Ni, platinum-group elements (PGEs) and Cu are sensitive to sulfide segregation and fractional crystallization during the evolution of mantle-derived magmas and can provide constraints on the genesis of continental basalts. Cenozoic intra-continental alkaline basalts in the Nanjing basaltic field, eastern China, include high-Ca and low-Ca varieties. All these basalts have poor PGE contents with Ir ranging from 0.016 ppb to 0.288 ppb and high Cu/Pd ratios from 0.7 × 105 to 4.7 × 105 (5.7 × 103 for DMM), indicating that they were derived from sulfide-saturated mantle sources with variable amounts of residual sulfide during melting or might undergo an early-sulfide segregation in the mantle. Relatively high Cu/Pd ratios along with high Pd concentrations for the high-Ca alkaline basalts indicate an additional removal of sulfide during magma ascent. Because these basalts have high, variable Pd/Ir ratios (2.8-16.8) with low Ce/Pb (9.9-19.7) ratios and εNd values (+ 3.6-+6.4), crustal contamination is proposed to be a potential process to induce the sulfide saturation and removal. Significantly increased Pd/Ir ratios for few high-Ca basalts can be explained by the fractionation of laurite or Ru-Os-Ir alloys with olivine or chromite. For low-Ca alkaline basalts, their PGE contents are well correlated with the MgO, Sc contents, incompatible element ratios (Lu/Hf, Na/Ti and Ca/Al) and Hf isotopes. Good correlations are also observed between Pd/Ir (or Rh/Ir) and Na/Ti (or Ca/Al) ratios. Variations of these elemental ratios and Hf isotopes is previously documented to be induced by the mixing of peridotite xenolith-released melts during ascent. Therefore, we suggest that such xenolith-magma interaction are also responsible for the variable PGE compositions of low

  4. Element spots in HgMn stars

    OpenAIRE

    Korhonen, Heidi

    2013-01-01

    A fraction of late B-type stars, the so-called HgMn stars, exhibit enhanced absorption lines of certain chemical elements, notably Hg and Mn, combined with an underabundance of He. For about a decade now the elements with anomalously high abundances in HgMn stars are known to be distributed inhomogeneously over the stellar surface. Temporal evolution of these elemental spots have been reported in a few HgMn stars, first secular evolution of the mercury spots in alpha And, and recently also a ...

  5. Element spots in HgMn stars

    CERN Document Server

    Korhonen, Heidi

    2013-01-01

    A fraction of late B-type stars, the so-called HgMn stars, exhibit enhanced absorption lines of certain chemical elements, notably Hg and Mn, combined with an underabundance of He. For about a decade now the elements with anomalously high abundances in HgMn stars are known to be distributed inhomogeneously over the stellar surface. Temporal evolution of these elemental spots have been reported in a few HgMn stars, first secular evolution of the mercury spots in alpha And, and recently also a fast evolution of yttrium and strontium spots in HD 11753. The fast evolution of spots in HD 11753 is combined with a slower change in the overall abundance of the affected elements. In this paper I review what is known of elemental spots in HgMn stars and their secular and fast temporal evolution.

  6. Element spots in HgMn stars

    Science.gov (United States)

    Korhonen, H.

    2014-11-01

    A fraction of late B-type stars, the so-called HgMn stars, exhibit enhanced absorption lines of certain chemical elements, notably Hg and Mn, combined with an underabundance of He. For about a decade it has been known that the elements with anomalously high abundances in HgMn stars are distributed inhomogeneously over the stellar surface. Observation of the temporal evolution of those spots has been reported in a few HgMn stars, first of a secular evolution of the mercury spots in α And, and more recently of a fast evolution of yttrium and strontium spots in HD 11753. The fast evolution of spots in HD 11753 is combined with a slower change in the overall abundance of the elements affected. In this paper I review what is known about these ``elemental spots'' in HgMn stars and their secular and fast temporal evolution.

  7. SEQUESTRATION OF SUBSURFACE ELEMENTAL MERCURY (HG0)

    Science.gov (United States)

    Elemental mercury (Hg0) is a metal with a number of atypical properties, which has resulted in its use in myriad anthropogenic processes. However, these same properties have also led to severe local subsurface contamination at many places where it has been used. As...

  8. The effects of melt depletion and metasomatism on highly siderophile and strongly chalcophile elements: S-Se-Te-Re-PGE systematics of peridotite xenoliths from Kilbourne Hole, New Mexico

    Science.gov (United States)

    Harvey, Jason; König, Stephan; Luguet, Ambre

    2015-10-01

    The composition of the Earth's upper mantle is a function of melt depletion and subsequent metasomatism; the latter obscuring many of the key characteristics of the former, and potentially making predictions of Primitive Upper Mantle (PUM) composition problematic. To date, estimates of PUM abundances of highly siderophile element (HSE = platinum group elements (PGE) and Re) and the strongly chalcophile elements Se and Te, have been the subject of less scrutiny than the lithophile elements. Critically, estimates of HSE and strongly chalcophile element abundances in PUM may have been derived by including a large number of metasomatized and refertilized samples whose HSE and chalcophile element abundances may not be representative of melt depletion alone. Unravelling the effects of metasomatism on the S-Se-Te-HSE abundances in peridotite xenoliths from Kilbourne Hole, New Mexico, USA, potentially provides valuable insights into the abundances of HSE and strongly chalcophile element abundances in PUM. Superimposed upon the effects of melt depletion is the addition of metasomatic sulfide in approximately half of the xenoliths from this study, while the remaining half have lost sulfide to a late S-undersaturated melt. Despite these observations, the Kilbourne Hole peridotite xenoliths have HSE systematics that are, in general, indistinguishable from orogenic peridotites and peridotite xenoliths used for determination of PUM HSE abundances. This study represents the first instance where Se-Te-HSE systematics in peridotite xenoliths are scrutinized in detail in order to test their usefulness for PUM estimates. Despite earlier studies attesting to the relative immobility of Se during supergene weathering, low S, Se, Os and Se/Te in peridotite xenoliths suggests that Se may be more mobile than originally thought, and for this reason, peridotite xenoliths may not be suitable for making predictions of the abundance of these elements in PUM. Removal of Se, in turn, lowers the

  9. Should I Stay or Should I Go? The Effects of Weathering on Siderophile and Chalcophile Element Mobility in Mantle-Derived Sulfides

    Science.gov (United States)

    Harvey, J.; Warren, J. M.; Humayun, M.; Walshaw, R.

    2015-12-01

    Jason Harvey1,2, Jessica M Warren2, Munir Humayun3, Richard D Walshaw1 School of Earth and Environment, University of Leeds, Leeds, UK Dept. of Earth and Environmental Sciences, Stanford University, Stanford CA, USA National High Magnetic Field Laboratory, Florida State University, Tallahassee FL, USA Peridotite xenoliths possess lower abundances of S and Os than peridotite massifs. This has been attributed to the ingress of meteoric water, which oxidizes sulfide, removing sulfur as soluble sulfate, while volatilizing Os to its more mobile OsO4 form[1]. Selenium is considered to be less mobile than S under oxidizing conditions[2]. This assumption was challenged recently when peridotite xenoliths from Kilbourne Hole were analysed for bulk-rock PGE-S-Se-Te-Re abundances[3]. The sulfides they contained had clearly experienced varying degrees of oxidation to Fe-oxyhydroxides, but yielded chondritic bulk-rock Se/S, consistent with values found in massif peridotites. This requires that Se is mobile during supergene weathering, otherwise supra-chondritic Se/S would be generated. Here, we present the results of a LA-ICP-MS investigation into the highly siderophile element (HSE) and chalcophile element abundances of ca. 20 BMS grains from one of the same Kilbourne Hole xenoliths of the former bulk-rock study[3]. Osmium abundance and Os/Ir (where not fractionated by high temperature processes involving sulfide) are well correlated with both Se and S across a wide range of oxidation. Other platinum group elements (Ir, Ru, Rh, Pt, Pd) show no obvious signs of mobility with decreasing S (or Se) abundance. The positive co-variation between S and Se for a wide range of S abundance adds credence to the theory that Se may also be mobile during the oxidative breakdown of peridotite- hosted sulfides. Using Se as a proxy for S abundance in peridotite xenoliths should therefore be used with care. Moreover, the attribution of chondritic Se/S in peridotites to bulk-earth compositions may

  10. Oxidation of elemental Hg in anthropogenic and marine airmasses

    Directory of Open Access Journals (Sweden)

    H. Timonen

    2013-03-01

    Full Text Available Mercury (Hg is a neurotoxin that bioaccumulates in the food chain. Mercury is emitted to the atmosphere primarily in its elemental form, which has a long lifetime allowing global transport. It is known that atmospheric oxidation of gaseous elemental mercury (GEM generates reactive gaseous mercury (RGM which plays an important role in the atmospheric mercury cycle by enhancing the rate of mercury deposition to ecosystems. However, the primary GEM oxidants, and the chemical composition of RGM are poorly known. Using speciated mercury measurements conducted at the Mt. Bachelor Observatory since 2005 we present two previously unidentified sources of RGM to the free troposphere (FT. Firstly, we observed elevated RGM concentrations, large RGM/GEM-ratios, and anti-correlation between RGM and GEM during Asian long-rang transport events, demonstrating that RGM is formed from GEM by in-situ oxidation in some anthropogenic pollution plumes in the FT. During the Asian pollution events the measured RGM/GEM-enhancement ratios reached peak values, up to ~0.20, which are significantly larger than ratios typically measured (RGM/GEM −3, high RGM/GEM-ratios (up to 1, and very low ozone levels during these events provide observational evidence indicating significant GEM oxidation in the lower FT in some conditions.

  11. New technique for quantification of elemental hg in mine wastes and its implications for mercury evasion into the atmosphere

    Science.gov (United States)

    Jew, A.D.; Kim, C.S.; Rytuba, J.J.; Gustin, M.S.; Brown, Gordon E., Jr.

    2011-01-01

    Mercury in the environment is of prime concern to both ecosystem and human health. Determination of the molecular-level speciation of Hg in soils and mine wastes is important for understanding its sequestration, mobility, and availability for methylation. Extended X-ray absorption fine structure (EXAFS) spectroscopy carried out under ambient P-T conditions has been used in a number of past studies to determine Hg speciation in complex mine wastes and associated soils. However, this approach cannot detect elemental (liquid) mercury in Hg-polluted soils and sediments due to the significant structural disorder of liquid Hg at ambient-temperature. A new sample preparation protocol involving slow cooling through the crystallization temperature of Hg(0) (234 K) results in its transformation to crystalline ??-Hg(0). The presence and proportion of Hg(0), relative to other crystalline Hg-bearing phases, in samples prepared in this way can be quantified by low-temperature (77 K) EXAFS spectroscopy. Using this approach, we have determined the relative concentrations of liquid Hg(0) in Hg mine wastes from several sites in the California Coast Range and have found that they correlate well with measured fluxes of gaseous Hg released during light and dark exposure of the same samples, with higher evasion ratios from samples containing higher concentrations of liquid Hg(0). Two different linear relationships are observed in plots of the ratio of Hg emission under light and dark conditions vs % Hg(0), corresponding to silica-carbonate- and hot springs-type Hg deposits, with the hot springs-type samples exhibiting higher evasion fluxes than silica-carbonate type samples at similar Hg(0) concentrations. Our findings help explain significant differences in Hg evasion data for different mine sites in the California Coast Range. ?? 2011 American Chemical Society.

  12. Investigation of the E2 and E3 matrix elements in 200Hg using inelastic scattering

    Directory of Open Access Journals (Sweden)

    Rand E. T.

    2014-03-01

    Full Text Available A nuclear structure campaign has been initiated to investigate the isotopes of mercury near A = 199. Currently 199Hg provides the most stringent limit on an atomic electric dipole moment (EDM. The observation of a permanent EDM would represent a clear signal of CP violation from new physics beyond the Standard Model. Theoretical calculations for 199Hg are very difficult and give varied predictions for the excited-state spectrum. Understanding the E2 and E3 strengths in the neighbouring even-even isotopes of mercury will make it possible to develop a nuclear structure model for the Schiff strength based on these matrix elements, and thereby constrain present model predictions of the contribution of octupole collectivity to the Schiff moment of the nucleus.

  13. 20-element HgI2 energy dispersive x-ray array detector system

    International Nuclear Information System (INIS)

    This paper describes recent progress in the development of HgI2 energy dispersive x-ray arrays and associated miniaturized processing electronics for synchrotron radiation research applications. The experimental results with a 20-element array detector were obtained under realistic synchrotron beam conditions at SSRL. An energy resolution of 250 eV (FWHM) at 5.9 keV (Mn-Kalpha) was achieved. Energy resolution and throughput measurements versus input count rate and energy of incoming radiation have been measured. Extended X-ray Absorption Fine Structure (EXAFS) spectra were taken form diluted samples simulating proteins with nickel

  14. 20 element HgI sub 2 energy dispersive x-ray array detector system

    Energy Technology Data Exchange (ETDEWEB)

    Iwanczyk, J.A.; Dorri, N.; Wang, M.; Szczebiot, R.W.; Dabrowski, A.J. (Xsirius, Inc., Marina Del Rey, CA (United States)); Hedman, B.; Hodgson, K.O. (Stanford Univ., CA (United States). Stanford Synchrotron Radiation Lab.); Patt, B.E. (EG and G Energy Measurements, Inc., Goleta, CA (United States))

    1991-01-01

    This paper describes recent progress in the development of HgI{sub 2} energy dispersive x-ray detector arrays and associated miniaturized processing electronics for synchrotron radiation research applications. The experimental results with a 20 element array detector were obtained under realistic synchrotron beam conditions at SSRL. An energy resolution of 250 eV (FWHM) at 5.9 keV (Mn-K{sub a}) was achieved. Energy resolution and throughput measurements versus input count rate and energy of incoming radiation have been measured. Extended X-ray Absorption Fine Structure (EXAFS) spectra were taken from diluted samples simulating proteins with nickel.

  15. 20 element HgI{sub 2} energy dispersive x-ray array detector system

    Energy Technology Data Exchange (ETDEWEB)

    Iwanczyk, J.A.; Dorri, N.; Wang, M.; Szczebiot, R.W.; Dabrowski, A.J. [Xsirius, Inc., Marina Del Rey, CA (United States); Hedman, B.; Hodgson, K.O. [Stanford Univ., CA (United States). Stanford Synchrotron Radiation Lab.; Patt, B.E. [EG and G Energy Measurements, Inc., Goleta, CA (United States)

    1991-12-31

    This paper describes recent progress in the development of HgI{sub 2} energy dispersive x-ray detector arrays and associated miniaturized processing electronics for synchrotron radiation research applications. The experimental results with a 20 element array detector were obtained under realistic synchrotron beam conditions at SSRL. An energy resolution of 250 eV (FWHM) at 5.9 keV (Mn-K{sub a}) was achieved. Energy resolution and throughput measurements versus input count rate and energy of incoming radiation have been measured. Extended X-ray Absorption Fine Structure (EXAFS) spectra were taken from diluted samples simulating proteins with nickel.

  16. 20-element HgI[sub 2] energy dispersive x-ray array detector system

    Energy Technology Data Exchange (ETDEWEB)

    Iwanczyk, J.S.; Dorri, N.; Wang, M.; Szczebiot, R.W.; Dabrowski, A.J. (Xsirius, Inc., Marina del Ray, CA (United States)); Hedman, B.; Hodgson, K.O. (Stanford Univ., CA (United States). Stanford Synchrotron Radiation Lab.); Patt, B.E. (EG and G Energy Measurements, Inc., Goleta, CA (United States))

    1992-10-01

    This paper describes recent progress in the development of HgI[sub 2] energy dispersive x-ray arrays and associated miniaturized processing electronics for synchrotron radiation research applications. The experimental results with a 20-element array detector were obtained under realistic synchrotron beam conditions at SSRL. An energy resolution of 250 eV (FWHM) at 5.9 keV (Mn-K[sub alpha]) was achieved. Energy resolution and throughput measurements versus input count rate and energy of incoming radiation have been measured. Extended X-ray Absorption Fine Structure (EXAFS) spectra were taken form diluted samples simulating proteins with nickel.

  17. 20 element HgI2 energy dispersive x-ray array detector system

    International Nuclear Information System (INIS)

    This paper describes recent progress in the development of HgI2 energy dispersive x-ray detector arrays and associated miniaturized processing electronics for synchrotron radiation research applications. The experimental results with a 20 element array detector were obtained under realistic synchrotron beam conditions at SSRL. An energy resolution of 250 eV (FWHM) at 5.9 keV (Mn-Ka) was achieved. Energy resolution and throughput measurements versus input count rate and energy of incoming radiation have been measured. Extended X-ray Absorption Fine Structure (EXAFS) spectra were taken from diluted samples simulating proteins with nickel

  18. The 20 element HgI2 energy dispersive x ray array detector system

    Science.gov (United States)

    Iwanczyk, J. A.; Dorri, N.; Wang, M.; Szczebiot, R. W.; Dabrowski, A. J.; Hedman, B.; Hodgson, K. O.; Patt, B. E.

    1991-11-01

    This paper describes recent progress in the development of HgI2 energy dispersive x-ray detector arrays and associated miniaturized processing electronics for synchrotron radiation research applications. The experimental results with a 20 element array detector were obtained under realistic synchrotron beam conditions at SSRL. An energy resolution of 250 eV (FWHM) at 5.9 keV (Mn-K(sub a)) was achieved. Energy resolution and throughput measurements versus input count rate and energy of incoming radiation have been measured. Extended X-ray Absorption Fine Structure (EXAFS) spectra were taken from diluted samples simulating proteins with nickel.

  19. First principle study of the interaction of elemental Hg with small neutral, anionic and cationic Pd ( = 1-6) clusters

    Indian Academy of Sciences (India)

    Shamoon Ahmad Siddiqui; Nadir Bouarissa

    2013-11-01

    Density functional theory (DFT)-based calculations have been performed so as to study the interaction of elemental mercury (Hg) with small neutral, cationic and anionic palladium clusters (Pd, = 1-6). Results of these calculations clearly indicate that frontier molecular orbital (FMO) theory is a useful method to predict the selectivity of Hg adsorption. Binding energies of Hg on cationic Pd clusters are generally found to be greater than those on neutral and anionic clusters. Results of natural bond orbital (NBO) analysis show that the flow of electrons in the neutral and charged complexes is mainly due to s orbitals of Hg. NBO analysis also indicates that, in most of the cases, the binding energies of Hg with Pdn clusters are directly proportional to charge transfer, i.e., greater the charge transfer, higher is the binding energy.

  20. Assessment of daily dietary intake of Hg and some essential elements in diets of children from the Amazon region

    International Nuclear Information System (INIS)

    Daily dietary intake of Hg and some essential elements in diets of children from communities in the Jau National Park, Amazon region, were assessed. Diet samples were analyzed for total Hg content using cold vapor atomic absorption spectrometry and Ca, Fe, K, Na, Se and Zn contents by instrumental neutron activation analysis. The weekly tolerable provisional intake for Hg in the communities studied varied from 13 to 57 μg of Hg per kg of body weight, exceeding the limit of 5 μg x kg-1 set by the WHO. Comparison of the daily dietary intake values to the new Dietary Reference Intakes (4-8 years), showed prevalence of inadequacy. (author)

  1. Determination of Hg and other trace elements in soil using neutron activation analysis

    International Nuclear Information System (INIS)

    In the early 1950's, a federal facility in Oak Ridge, Tenessee, used a process that required the use of Hg to produce 8Li. It was disclosed to the public in 1983 that about 2.4 millions pounds of Hg had been released into the ecosystem. The primary route of mercury into the environment was a stream, East Fork Poplar Creek, whose head waters are in the vicinity of the plant. As part of a study to determine the distribution of Hg as well as As, Cr, Sb, Se, U and Zn along the flood plains of the creek, a procedure using neutron activation analysis was developed and is described below. The procedure, typical sample analysis result for Hg, and quality assurance and control data are discussed. (author) 4 refs.; 1 fig.; 6 tabs

  2. 合金元素对Mg-Hg-Ga阳极材料电化学行为的影响%Influence of Alloying Elements on Electrochemical Behavior of Mg-Hg-Ga Anodes

    Institute of Scientific and Technical Information of China (English)

    冯艳; 王日初; 彭超群

    2011-01-01

    用恒电流法,析氢法和交流阻抗法等方法测试了合金元素Hg和Ga对镁阳极电化学腐蚀行为的影响,并用扫描电镜和X射线衍射法分析了合金元素Hg和Ga对镁阳极的显微组织和相结构的影响。结果表明:铸态的Mg-4.8%Hg-8.8Ga合金晶界析出Mg5Ga2和Mg21Ga5Hg3相,铸态的Mg-8.8%Hg-8%Ga和Mg-7.2%Hg-8%Ga合金晶界析出Mg21Ga5Hg3相,铸态的Mg-7.2%Hg-2.6%Ga合金析出Mg3Hg和Mg21Ga5Hg3相。各合金析氢速率从小到大依次为:Mg-7.2%Hg-2.6%Ga合金,Mg-4.8%Hg-8%Ga合金,Mg-7.2%Hg-8%Ga合金和Mg-8.8%Hg-8%Ga合金。最小的析氢速率为1.75ml/(cm2.min)。各合金电化学活性从大到小依次为:Mg-8.8%Hg-8%Ga合金,Mg-7.2%Hg-8%Ga合金,Mg-4.8%Hg-8%Ga合金和Mg-7.2%Hg-2.6%Ga合金。在200 mA/cm2恒电流测试中最负的稳定电位-1.932 V出现在Mg-8.8%Hg-8%Ga合金中。%The effects of alloying elements Hg and Ga on the electrochemical corrosion behavior of Mg anodes were studied by galvanostatic tests,hydrogen evolution tests and electrochemical impedance spectra(EIS) measurements under different polarization conditions.Scanning electron microscopy(SEM) and X-ray diffractometry(XRD) were employed to detect the microstructure and phase relationship of the above alloys.Attention was paid to the combined effect of Hg and Ga on electrochemical properties and microstructures.The results show that Mg5Ga2 and Mg21Ga5Hg3 phases precipitated along the grain boundaries in cast Mg-4.8%Hg-8%Ga alloy.Mg21Ga5Hg3 phases precipitated in cast Mg-8.8%Hg-8%Ga and Mg-7.2%Hg-8%Ga alloys.Mg3Hg and Mg21Ga5Hg3 phases precipitated in cast Mg-7.2%Hg-2.6%Ga alloy.The sequential order of the hydrogen evolution corrosion rates from small to large is Mg-7.2%Hg-2.6%Ga alloy,Mg-4.8%Hg-8%Ga alloy,Mg-7.2%Hg-8%Ga alloy,and Mg-8.8%Hg-8%Ga alloy.The smallest hydrogen evolution corrosion rate is 1.75 ml/(cm2·min).The sequential order of the electrochemical activity from large to small is Mg-8.8%Hg-8

  3. Periodicity of element and compounds in U,Bi,Pb,Hg,Pt,Sn,Zn,Cu,Ni,Fe deposits

    International Nuclear Information System (INIS)

    The analysis of succession of mineral formation of various types of endogene mineralization at U, Bi, Pb, Hg, Sn, Zn, Cu, Na, Co, Fe deposits is performed. It is shown that despite the difference in genetic types and physico-chemical conditions of formation in different type systems the regular succession in mineral formation exists. The main succession factors of mineral formation in all systems are charge, atomic masses and volume, electronic configuration, entropy and valent state of the element. In uranium deposits penta-element, sulphide-pitchblende, Ti-U-formations. In the above formation the following succession of mineral formation is established: 1) silicate-oxidic, association, 2) quartz-sulphide, 3) quartz-carbonate-pitchblende, 4) fluorite-arsenide, 5) quartz-hematite

  4. Valence of elements in HgBa2Can-1CunO2n+2+d (n=1, 2, 3, 4)

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Valence of elements in HgBa2Can-1CunO2n+2+d (n=1, 2, 3, 4) (both argon and oxygen annealed samples) were calculated. The result indicated for both argon and oxygen annealed samples, Hg had the lowest valence for the highest Tc sample. For fixed n, the valence of Cu in oxygen annealed samples was larger than that in argon annealed samples, indicating that oxygen annealed samples produce more carriers than argon annealed samples.

  5. Broadening and shift of the intercombination spectral line of the second group elements (Hg, Cd and Zn) perturbed by inert gases

    International Nuclear Information System (INIS)

    The Van der Waals and Lennard - Jones potential parameters for the ground and exited states of the second group elements (Hg, Cd and Zn) perturbed by inert gases (Xe, Kr, Ar, Ne and He) have been calculated using coulomb approximation. The basis of the Lindholm -Foley impact theory and the calculated potential parameters are used for calculating the collision broadening and shift coefficients β and δ for the intercombination lines 253.7, 326.1 and 307.6 nm of Hg, Cd and Zn atoms respectively when they are colliding with inert gas atoms . The calculating coefficients of β and δ are compared with their corresponding experimental values, taken from literatures

  6. Identification of 209Hg

    International Nuclear Information System (INIS)

    The new neutron-rich nuclide 209Hg has been identified for the first time. An on-line, gas-thermochromatographic technique was developed for rapidly separating the Hg-element products from 600-MeV 18O+natPb(thick target) reaction system. A special detection arrangement was used in order to detect the weak γ-activities of the neutron-rich Hg isotopes. The half-life of 209Hg was determined to be 35-6+9 s. (orig.)

  7. Certification of trace element contents (As, Cd, Co, Cu, Fe, Mn, Hg, Na, Pb and Zn) in a fly ash obtained from the combustion of pulverised coal

    International Nuclear Information System (INIS)

    The element contents of As, Cd, Co, Cu, Fe, Mn, Hg, Na, Pb and Zn of a fly ash from pulverised coal are certified. The procedures and their results for the homogenisation, the contamination and homogeneity checks and the analytical campaign are reported. The certified mass fractions and indicative values for Cr, Ni, Th, V and water soluble sulphate are given. The work was carried out within the framework of the activities of the Community Bureau of Reference (BCR) of the Commission of the European Communities. (orig.)

  8. Functional role of inorganic trace elements in angiogenesis part III: (Ti, Li, Ce, As, Hg, Va, Nb and Pb).

    Science.gov (United States)

    Saghiri, Mohammad Ali; Orangi, Jafar; Asatourian, Armen; Sorenson, Christine M; Sheibani, Nader

    2016-02-01

    Many essential elements exist in nature with significant influence on human health. Angiogenesis is vital in developmental, repair, and regenerative processes, and its aberrant regulation contributes to pathogenesis of many diseases including cancer. Thus, it is of great importance to explore the role of these elements in such a vital process. This is third in a series of reviews that serve as an overview of the role of inorganic elements in regulation of angiogenesis and vascular function. Here we will review the roles of titanium, lithium, cerium, arsenic, mercury, vanadium, niobium, and lead in these processes. The roles of other inorganic elements in angiogenesis were discussed in part I (N, Fe, Se, P, Au, and Ca) and part II (Cr, Si, Zn, Cu, and S) of these series. The methods of exposure, structure, mechanisms, and potential activities of these elements are briefly discussed. An electronic search was performed on the role of these elements in angiogenesis from January 2005 to April 2014. These elements can promote and/or inhibit angiogenesis through different mechanisms. The anti-angiogenic effect of titanium dioxide nanoparticles comes from the inhibition of angiogenic processes, and not from its toxicity. Lithium affects vasculogenesis but not angiogenesis. Nanoceria treatment inhibited tumor growth by inhibiting angiogenesis. Vanadium treatment inhibited cell proliferation and induced cytotoxic effects through interactions with DNA. The negative impact of mercury on endothelial cell migration and tube formation activities was dose and time dependent. Lead induced IL-8 production, which is known to promote tumor angiogenesis. Thus, understanding the impact of these elements on angiogenesis will help in development of new modalities to modulate angiogenesis under various conditions. PMID:26638864

  9. Assessment of micro, macro, toxic elements (Cd, Hg, Pb) and fatty acids profile in consumed fish commercially available in Cananeia and Cubatao, Sao Paulo State

    International Nuclear Information System (INIS)

    Aside from their nutritional importance, fish are considered one of the most important bio indicators in aquatic systems for the estimation of pollution levels by toxic metals. This is so, since fish can bio accumulate these elements and they occupy different trophic levels and present different sizes and age. The purpose of the present study was to contribute with important data for the knowledge of nutritional and toxic constituents in muscles of the most consumed fish species from two coastal regions, Cananeia and Cubatao. Cananeia fish species analyzed were: Micropogonias furnieri (Corvina), Macrodon ancylodon (Pescada), Centropomus undecimalis (Robalo peba) and Mugil platanus (Tainha). From Cubatao, Micropogonias furnieri (Corvina), Macrodon ancylodon (Pescada), Menticirrhus americanus (Perna de moca), Sardella braziliensis (Sardinha) and Mugil liza (Tainha). For this study, analytical methodologies were developed and validated, regarding precision and accuracy, by means of certified reference materials. Micronutrients (Ca, Fe, K, Na, Se and Zn) and some trace elements (As, Br, Co, Cr, Rb) in fish muscle were determined by means of neutron activation analysis (NAA). Cold Vapor Atomic Absorption Spectrometry (CV AAS) was used for total Hg determination and Electrothermal Atomic Absorption Spectrometry (ET AAS) for Cd and Pb determinations. Proximate composition determinations according to AOAC methodologies and fatty acids profiles by gas chromatography were done in these muscle fish samples. Regarding fatty acids profile from the ω-6 family, Tainha species pool presented the highest values (8.9%) and Pescada species pool the lowest ones (4.4%) for Cananeia species. Fatty acids from the ω-3 family, Sardinha pool species presented the highest values (31.8%) for all species analyzed. Regarding micronutrients content great concentration variations between individual of the same species and between different species were observed. Discriminate analysis was used

  10. Toxic elements (As, Se, Cd, Hg, Pb) and their mineral and technogenic formations in the snow cover in the vicinity of the industrial enterprises of Tomsk

    International Nuclear Information System (INIS)

    Snow samples were collected in four industrial areas of Tomsk where brickworks, factories for the production of reinforced concrete structures, machine repair industries and local boilers, petrochemical plant and thermal power station are located. Study of insoluble fraction of aerosols in snow and melted snow water was performed to determine the contents of the emissions from these facilities. The insoluble fraction of aerosols in snow is aerosol particles deposited on snow cover. As, Se, Cd, Hg, Pb concentration was analyzed by inductively coupled plasma mass spectrometry (ICP-MS). Mineral modes of the elements were determined by scanning electron microscope. It was found the snow cover is mainly polluted by As, Se, Cd, Hg, Pb in the thermal power station impact area, by As – in the brickworks impact area, by Se – in the impact area of densely located factories for the production of reinforced concrete structures, machine repair industries and local boilers. The research results show that the mineral modes of As are associated with arsenopyrite, of Pb – with galena in the insoluble fraction of aerosols in snow

  11. Confirmation of the Decay of 283112 and First Indication for Hg-like Behavior of Element 112

    International Nuclear Information System (INIS)

    Two gas phase adsorption chemistry experiments aimed at the chemical characterization of element 112 using its isotope 283112 have been performed at the Flerov Laboratory for Nuclear Reactions (FLNR) Dubna, Russia. The applied Insitu-Volatilization and On-line Detection (IVO) technique is a thermochromatographic system combining the determination of the deposition temperature of volatile elements on a surface along a temperature gradient with an efficient detection of the deposited species by event-by-event alpha and SF-fragment spectroscopy. Two possibilities to produce the isotope 283112 were used: 1.) the direct production reaction 238U(48Ca,3n)283112; 2.) the reaction 242Pu(48Ca,3n), where the primary product 287114, decays via alpha emission to 283112 with a half-life of 0.5 s. The chemistry experiments were aimed at a chemical identification of 283112 and an independent confirmation of its decay properties. In the direct reaction no decays related to 283112 were observed. However, two decay chains unambiguously attributed to the decay of 283112 were observed using the second production path. Previously reported observation of 283112 and 279Ds and their decay properties were confirmed. From its thermochromatorgaphic deposition first thermochemical data were deduced for element 112, unveiling it as a typical group 12 element

  12. Metallic elements (Ca, Hg, Fe, K, Mg, Mn, Na, Zn) in the fruiting bodies of Boletus badius.

    Science.gov (United States)

    Kojta, Anna K; Falandysz, Jerzy

    2016-06-01

    The aim of this study was to investigate and compare the levels of eight metallic elements in the fruiting bodies of Bay Bolete (Boletus badius; current name Imleria badia) collected from ten sites in Poland to understand better the value of this popular mushroom as an organic food. Bay Bolete fruiting bodies were collected from the forest area near the towns and villages of Kętrzyn, Poniatowa, Bydgoszcz, Pelplin, Włocławek, Żuromin, Chełmno, Ełk and Wilków communities, as well as in the Augustów Primeval Forest. Elements such as Ca, Fe, K, Mg, Mn, Na and Zn were analyzed by inductively coupled plasma atomic emission spectroscopy (ICP-OES), and mercury by cold vapor atomic absorption spectrometry (CV-AAS). This made it possible to assess the nutritional value of the mushroom, as well as possible toxicological risks associated with its consumption. The results were subjected to statistical analysis (Kruskal-Wallis test, cluster analysis, principal component analysis). PMID:26830580

  13. Determination of Hg and other elements in fish and plant samples from Amazonic region, by neutron activation analysis; Determinacao de Hg e outros elementos de interesse em amostras de peixes e plantas da regiao amazonica, por analise por ativacao com neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Favaro, Debora I.T.; Vasconcellos, Marina B.A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Supervisao de Radioquimica; Fostier, Anne Helene [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil). Lab. de Quimica Analitica

    1996-07-01

    In the present work the region of Serra do Navio, Amapa State, was chosen to asses the Hg contamination due to gold mining activities. As part of monitoring of this region, fishes and plants were collected and analysed by instrumental neutron activation (INAA). Through this method it was possible to determine the concentration of the elements: As, Ca, Cr, Co, Fe, Hg, Rb, Sb, Se and Zn in fishes and Ca, Co, Cr, Fe, Hg, La, Na, Rb, Sb, Sc, Se and Zn in plants. Mercury concentrations found in fishes ranged from 0.64 to 1.11 {mu}/g and from 0.83 to 0.15 {mu}g/g in plants. These results were compared with those obtained by the atomic absorption technique and they agreed well. The accuracy and precision of the INAA method were checked by means of analyses of reference materials. (author)

  14. Elemental abundance analyses with Coudé Echelle spectrograms from the TÜBİTAK National Observatory of Turkey: I. The HgMn stars 11 Per, HR 2801, and ν Cnc

    Science.gov (United States)

    Adelman, S. J.; Yüce, K.

    2010-08-01

    Using coadded spectrograms taken with the Coudé Echelle Spectrograph (CES) of the 1.50-m Russian-Turkish Telescope of the TÜBİTAK National Observatory (TUG) near Antalya in Turkey, elemental abundance analyses of three HgMn stars 11 Per, HR 2801, and ν Cnc were performed. Comparisons are made with spectra obtained with the long camera of the Dominion Astrophysical Observatory (DAO) coudé spectrograph and its SITe4 CCD. The CES equivalent widths are about 12% larger than that for the DAO long camera. Our first results from TUG data/spectra show that all three stars exhibit the Hg II λ3984 line and somewhat diverse abundance patterns. 11 Per tends to have underabundant light elements with underabundant and overabundant Fe-peak elements. HR 2801 has mostly underabundant elements, with a few elements having solar abundances while N and Mn are overabundant. The coolest star ν Cnc has light elements having mostly solar abundances, overabundant iron group abundances, and very overabundant SrYZr and Ba. Comparisons with the abundance patterns of other HgMn stars show that they have a wide diversity of abundance patterns. Tables 2 and 6 are available at the CDS via http://cdsarc.u-strasbg.fr/cgi-bin/qcat?J/AN/331/785.

  15. The Vein-type Zn-(Pb, Cu, As, Hg) mineralization at Fedj Hassene ore field, North-Western Tunisia: Mineralogy, Trace Elements, Sulfur Isotopes and Fluid Inclusions

    International Nuclear Information System (INIS)

    The Fedj Hassene district is localized at the edge of the Tuniso-Algerian border 10 km of Ghardimaou area. It consists of a Zn-Pb vein type with minor amounts of Cu-As-Hg. The total Zn reserves are about 370.000t. The mineralization occurs within sub parallel fractures to the Ain El Kohla ESE-WNW fault. Host rocks consist of limestones and marly limestones of the Middle Turonian. In the principal lode of Fedj Hassene, the mineralization occurs as vein filling of massive and brecciated brown sphalerite and minor galena ore with gangue. Other trace minerals are pyrite, chalcopyrite, orpiment, realgar, smithsonite and cerussite. LA-ICP-MS analyses in sphalerites show mean contents of 0,84 wt% Fe, 0,14 wt% Cd and 0,02 wt% Mn Ore. Fluid inclusions study in calcite and sphalerite reveals one mineralizing fluid characterized by an average salinity 23% wt NaCl with decreasing homogenisation temperature. In fact the temperature shows decrease from sphalerite to calcite. The fluid density that corresponds to trapping pressure ranges between 1.00 g/cm3 and 1.11 g/cm3 and pressure close to 200 bars. Micro thermometric data in fluid inclusion hosted by gangue mineral presented by calcite show an average temperature of formation around 194 degree centigrade. These inclusions homogenized to the liquid phase between 156 degree centigrade and 210 degree centigrade and salinities values ranging from 22 to 28 wt% NaCl and an average around 23% wt NaCl. The δ34S (VCDT) values of sphalerite are in the range of + 4,6% to 6,4% (average=5,6%). Thermochemical reduction of Triassic sulfate by reaction with hydro-carbons is the most probable source for the heavy and the narrow range of the dδ34S values. Mineralogical, geochemical of trace elements, fluid inclusions and sulfur isotopes studies allow to include the vein-type ore field of Fedj Hassene in the polymetallic (Pb-Zn-As-Hg) vein mineralization of the nappe zone in northern Tunisia and north eastern Algeria. (Author) 29 refs.

  16. Minor and trace elements in some meteoritic minerals.

    Science.gov (United States)

    Allen, R. O., Jr.; Mason, B.

    1973-01-01

    Despite the information available (Mason, 1971) on trace elements in different types of meteorites, relatively little is known about the distribution of these elements among the individual mineral phases. The mineral phases including olivine, orthopyroxene, clinipyroxene, troilite, nickel-iron, plagioclase, chromite, and the phosphates were separated from several meteorites. The purified minerals were analyzed for trace and minor elements by spark source mass spectrometry and instrumental neutron activation analysis. The elements are classified as siderophile, lithophile, and chalcophile.

  17. The Vein-type Zn-(Pb, Cu, As, Hg) mineralization at Fedj Hassene ore field, North-Western Tunisia: Mineralogy, Trace Elements, Sulfur Isotopes and Fluid Inclusions; Le champ filonien a Zn-(Pb, Cu, As, Hg) du district minier de Fedj Hassene (Nord Ouest de la Tunisie): Mineralogie, Elements en traces, Isotopes du Soufre et Inclusions Fluides

    Energy Technology Data Exchange (ETDEWEB)

    Bejaouil, J.; Bouhlel, S.; Barca, D.; Braham, A.

    2011-07-01

    The Fedj Hassene district is localized at the edge of the Tuniso-Algerian border 10 km of Ghardimaou area. It consists of a Zn-Pb vein type with minor amounts of Cu-As-Hg. The total Zn reserves are about 370.000t. The mineralization occurs within sub parallel fractures to the Ain El Kohla ESE-WNW fault. Host rocks consist of limestones and marly limestones of the Middle Turonian. In the principal lode of Fedj Hassene, the mineralization occurs as vein filling of massive and brecciated brown sphalerite and minor galena ore with gangue. Other trace minerals are pyrite, chalcopyrite, orpiment, realgar, smithsonite and cerussite. LA-ICP-MS analyses in sphalerites show mean contents of 0,84 wt% Fe, 0,14 wt% Cd and 0,02 wt% Mn Ore. Fluid inclusions study in calcite and sphalerite reveals one mineralizing fluid characterized by an average salinity 23% wt NaCl with decreasing homogenisation temperature. In fact the temperature shows decrease from sphalerite to calcite. The fluid density that corresponds to trapping pressure ranges between 1.00 g/cm{sup 3} and 1.11 g/cm{sup 3} and pressure close to 200 bars. Micro thermometric data in fluid inclusion hosted by gangue mineral presented by calcite show an average temperature of formation around 194 degree centigrade. These inclusions homogenized to the liquid phase between 156 degree centigrade and 210 degree centigrade and salinities values ranging from 22 to 28 wt% NaCl and an average around 23% wt NaCl. The {delta}{sup 3}4S (VCDT) values of sphalerite are in the range of + 4,6% to 6,4% (average=5,6%). Thermochemical reduction of Triassic sulfate by reaction with hydro-carbons is the most probable source for the heavy and the narrow range of the d{delta}{sup 3}4S values. Mineralogical, geochemical of trace elements, fluid inclusions and sulfur isotopes studies allow to include the vein-type ore field of Fedj Hassene in the polymetallic (Pb-Zn-As-Hg) vein mineralization of the nappe zone in northern Tunisia and north eastern

  18. The elements Se, Hg, Cr, Sb, Fe, Zn, Co, and Rb were investigated by neutron activation analysis in blood serum of leukemia patients and workers of metal coating industries

    International Nuclear Information System (INIS)

    Current universal interests in trace element studies are being spurred by our needs to determine trace element requirements and tolerance by organism, including relationships to animal and human health and disease, evaluate the potential bio magnification and bio toxicity of trace elements. The element Se, Hg, Cr, Sb, Fe, Zn, Co, and Rb were investigated in blood serum of 24 leukemia patients and 20 workers of metal coating of industries, using neutron activation analysis and gamma ray counting high purity germanium detector, it was possible to determine the above mentioned trace elements with great accuracy. The result of these investigations are described briefly. In the blood serum of leukemia patients, which were collected from Ali Asghar children Hospital, some increase of Fe and decrease of Se could be found, whereas the amount variation of other trace elements were negligible. The amount of Zn in the blood serum of these workers by comparison with 60 normal man indicates no change. Due to importance of trace elements in the human health we suggest that this investigation must be prolonged using more samples

  19. Hyperemesis Gravidarum (HG)

    Science.gov (United States)

    ... Treatments Risks Complications Impact Take a Poll If HG continued past mid-pregnancy , did you experience complications ... Understanding Hyperemesis | Overview About Hyperemesis Gravidarum Hyperemesis gravidarum (HG) is a severe form of nausea and vomiting ...

  20. 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.

  1. Assessment of micro, macro, toxic elements (Cd, Hg, Pb) and fatty acids profile in consumed fish commercially available in Cananeia and Cubatao, Sao Paulo State; Avaliacao de micro e macroelementos, elementos toxicos (Cd, Hg e Pb) e acidos graxos, em peixes disponiveis comercialmente para consumo em Cananeia e Cubatao, Estado de Sao Paulo

    Energy Technology Data Exchange (ETDEWEB)

    Curcho, Michel Rodrigues da Silva Morales

    2009-07-01

    Aside from their nutritional importance, fish are considered one of the most important bio indicators in aquatic systems for the estimation of pollution levels by toxic metals. This is so, since fish can bio accumulate these elements and they occupy different trophic levels and present different sizes and age. The purpose of the present study was to contribute with important data for the knowledge of nutritional and toxic constituents in muscles of the most consumed fish species from two coastal regions, Cananeia and Cubatao. Cananeia fish species analyzed were: Micropogonias furnieri (Corvina), Macrodon ancylodon (Pescada), Centropomus undecimalis (Robalo peba) and Mugil platanus (Tainha). From Cubatao, Micropogonias furnieri (Corvina), Macrodon ancylodon (Pescada), Menticirrhus americanus (Perna de moca), Sardella braziliensis (Sardinha) and Mugil liza (Tainha). For this study, analytical methodologies were developed and validated, regarding precision and accuracy, by means of certified reference materials. Micronutrients (Ca, Fe, K, Na, Se and Zn) and some trace elements (As, Br, Co, Cr, Rb) in fish muscle were determined by means of neutron activation analysis (NAA). Cold Vapor Atomic Absorption Spectrometry (CV AAS) was used for total Hg determination and Electrothermal Atomic Absorption Spectrometry (ET AAS) for Cd and Pb determinations. Proximate composition determinations according to AOAC methodologies and fatty acids profiles by gas chromatography were done in these muscle fish samples. Regarding fatty acids profile from the {omega}-6 family, Tainha species pool presented the highest values (8.9%) and Pescada species pool the lowest ones (4.4%) for Cananeia species. Fatty acids from the {omega}-3 family, Sardinha pool species presented the highest values (31.8%) for all species analyzed. Regarding micronutrients content great concentration variations between individual of the same species and between different species were observed. Discriminate analysis

  2. 4482 Element Multispectral Hybrid PV/PC HgCdTe IRFPA for High Resolution Coverage of 3.7 - 15.4 Micrometers for the AIRS Instrument

    Science.gov (United States)

    Rutter, James; Libonate, Scott; Denley, Brian; Gurnee, Mark N.; Robillard, Gene

    1996-01-01

    The Atmospheric Infrared Sounder (AIRS) is a key facility instrument in the NASA Earth Observing System (EOS) program, being implemented to obtain comprehensive long-term measurements of earth processes affecting global change. The instrument performs passive IR remote sensing using a high resolution grating spectrometer with a wide spectral coverage (3.7 - 15.4 m) directing radiation onto a hybrid HgCdTe IRFPA operating at 58K in a vacuum package cooled to 155K. The hybrid HgCdTe FPA consists of twelve modules, 10 with multiplexed photovoltaic detectors and two with individually leaded out photoconductive detectors. The complex FPA has a large optical footprint, 53 mm x 66 mm, and receives energy dispersed from the grating through a precision filter assembly containing 17 narrow band filters. The backside illuminated PV detector arrays are fabricated from P-on-n double layer LPE grown heterojunction detectors in a bilinear format of 50 m x 100 m detectors, with from 232 to 420 detectors per module. For the MWIR bands four PV modules cover the 3.7 m to 8.22 m region. Low detector capacitance and low noise preamplifiers in the ROIC are key to achieving high sensitivities in these bands. Uniform quantum efficiencies and detectivities exceeding 3E13 cm-rtHz/W have been achieved. The LWIR region is covered by six PV modules spanning 8.8 m to 13.75 m. High detector resistance and very low ROIC preamplifier input noise are key to achieving high sensitivity. A detectivity exceeding 2E11 cm-rtHz/W has been achieved at the longest wavelength. Two additional PC modules cover the longest spectral bands out to 15.4 m. This high performance multispectral focal plane has been built and integrated with the dewar assembly, and is currently being integrated with the complete AIRS sensor.

  3. Distribution and air-sea exchange of mercury (Hg) in the Yellow Sea

    OpenAIRE

    Z. J. Ci; X. S. Zhang; Wang, Z. W.; Niu, Z. C.; Diao, X. Y.; Wang, S. W.

    2011-01-01

    The Yellow Sea, surrounded by East China and the Korea Peninsula, is a potentially important receptor for anthropogenic mercury (Hg) emissions from East Asia. However, there is little documentation about the distribution and cycle of Hg in this marine system. During the cruise covering the Yellow Sea in July 2010, gaseous elemental mercury (GEM or Hg(0)) in the atmosphere, total Hg (THg), reactive Hg (RHg) and dissolved gaseous mercury (DGM, largely Hg(0)) in the waters were measured ...

  4. Results Of Hg Speciation Testing On DWPF SMECT-1, SMECT-3, And SMECT-5 Samples

    Energy Technology Data Exchange (ETDEWEB)

    Bannochie, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-01-07

    The Savannah River National Laboratory (SRNL) was tasked with preparing and shipping samples for Hg speciation by Eurofins Frontier Global Sciences, Inc. in Seattle, WA on behalf of the Savannah River Remediation (SRR) Mercury Task Team. The thirteenth shipment of samples was designated to include Defense Waste Processing Facility (DWPF) Slurry Mix Evaporator Condensate Tank (SMECT) from Sludge Receipt and Adjustment Tank (SRAT) Batch 736 and 738 samples. Triplicate samples of each material were prepared for this shipment. Each replicate was analyzed for seven Hg species: total Hg, total soluble (dissolved) Hg, elemental Hg [Hg(0)], ionic (inorganic) Hg [Hg(I) and Hg(II)], methyl Hg [CH3Hg-X, where X is a counter anion], ethyl Hg [CH3CH2-Hg-X, where X is a counter anion], and dimethyl Hg [(CH3)2Hg]. The difference between the total Hg and total soluble Hg measurements gives the particulate Hg concentration, i.e. Hg adsorbed to the surface of particulate matter in the sample but without resolution of the specific adsorbed species. The average concentrations of Hg species in the aqueous samples derived from Eurofins reported data corrected for dilutions performed by SRNL are tabulated.

  5. Results Of Hg Speciation Testing On DWPF SMECT-1, SMECT-3, And SMECT-5 Samples

    International Nuclear Information System (INIS)

    The Savannah River National Laboratory (SRNL) was tasked with preparing and shipping samples for Hg speciation by Eurofins Frontier Global Sciences, Inc. in Seattle, WA on behalf of the Savannah River Remediation (SRR) Mercury Task Team. The thirteenth shipment of samples was designated to include Defense Waste Processing Facility (DWPF) Slurry Mix Evaporator Condensate Tank (SMECT) from Sludge Receipt and Adjustment Tank (SRAT) Batch 736 and 738 samples. Triplicate samples of each material were prepared for this shipment. Each replicate was analyzed for seven Hg species: total Hg, total soluble (dissolved) Hg, elemental Hg [Hg(0)], ionic (inorganic) Hg [Hg(I) and Hg(II)], methyl Hg [CH3Hg-X, where X is a counter anion], ethyl Hg [CH3CH2-Hg-X, where X is a counter anion], and dimethyl Hg [(CH3)2Hg]. The difference between the total Hg and total soluble Hg measurements gives the particulate Hg concentration, i.e. Hg adsorbed to the surface of particulate matter in the sample but without resolution of the specific adsorbed species. The average concentrations of Hg species in the aqueous samples derived from Eurofins reported data corrected for dilutions performed by SRNL are tabulated.

  6. 40 CFR 60.4122 - Information requirements for Hg budget permit applications.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Information requirements for Hg budget... requirements for Hg budget permit applications. A complete Hg Budget permit application shall include the following elements concerning the Hg Budget source for which the application is submitted, in a...

  7. Microbial Oxidation of Hg(0) - Its Effect on Hg Stable Isotope Fractionation and Methylmercury Production

    Energy Technology Data Exchange (ETDEWEB)

    Yee, Nathan [Rutgers Univ., New Brunswick, NJ (United States); Barkay, Tamar [Rutgers Univ., New Brunswick, NJ (United States); Reinfelder, John [Rutgers Univ., New Brunswick, NJ (United States)

    2016-06-28

    Mercury (Hg) associated with mixed waste generated by nuclear weapons manufacturing has contaminated vast areas of the Oak Ridge Reservation (ORR). Neurotoxic methylmercury (MeHg) has been formed from the inorganic Hg wastes discharged into headwaters of East Fork Poplar Creek (EFPC). Thus, understanding the processes and mechanisms that lead to Hg methylation along the flow path of EFPC is critical to predicting the impacts of the contamination and the design of remedial action at the ORR. In part I of our project, we investigated Hg(0) oxidation and methylation by anaerobic bacteria. We discovered that the anaerobic bacterium Desulfovibrio desulfuricans ND132 can oxidize elemental mercury [Hg(0)]. When provided with dissolved elemental mercury, D. desulfuricans ND132 converts Hg(0) to Hg(II) and neurotoxic methylmercury [MeHg]. We also demonstrated that diverse species of subsurface bacteria oxidizes dissolved elemental mercury under anoxic conditions. The obligate anaerobic bacterium Geothrix fermentans H5, and the facultative anaerobic bacteria Shewanella oneidensis MR-1 and Cupriavidus metallidurans AE104 can oxidize Hg(0) to Hg(II) under anaerobic conditions. In part II of our project, we established anaerobic enrichment cultures and obtained new bacterial strains from the DOE Oak Ridge site. We isolated three new bacterial strains from subsurface sediments collected from Oak Ridge. These isolates are Bradyrhizobium sp. strain FRC01, Clostridium sp. strain FGH, and a novel Negativicutes strain RU4. Strain RU4 is a completely new genus and species of bacteria. We also demonstrated that syntrophic interactions between fermentative bacteria and sulfate-reducing bacteria in Oak Ridge saprolite mediate iron reduction via multiple mechanisms. Finally, we tested the impact of Hg on denitrification in nitrate reducing enrichment cultures derived from subsurface sediments from the Oak Ridge site, where nitrate is a major contaminant. We showed that there is an inverse

  8. Hg(0) absorption in potassium persulfate solution.

    Science.gov (United States)

    Ye, Qun-feng; Wang, Cheng-yun; Wang, Da-hui; Sun, Guan; Xu, Xin-hua

    2006-05-01

    The aqueous phase oxidation of gaseous elemental mercury (Hg(0)) by potassium persulfate (KPS) catalyzed by Ag(+) was investigated using a glass bubble column reactor. Concentration of gaseous mercury and potassium persulfate were measured by cold vapor atom absorption (CVAA) and ion chromatograph (IC), respectively. The effects of pH value, concentration of potassium persulfate and silver nitrate (SN), temperature, Hg(0) concentration in the reactor inlet and tertiary butanol (TBA), free radical scavenger, on the removal efficiency of Hg(0) were studied. The results showed that the removal efficiency of Hg(0) increased with increasing concentration of potassium persulfate and silver nitrate, while temperature and TBA were negatively effective. Furthermore, the removal efficiency of Hg(0) was much better in neutral solution than in both acidic and alkaline solution. But the influence of pH was almost eliminated by adding AgNO(3). High Hg(0) concentration has positive effect. The possible reaction mechanism of gaseous mercury was also discussed. PMID:16615172

  9. Further Studies, About New Elements Production, by Electrolysis of Cathodic Pd Thin–Long Wires, in Alcohol-Water Solutions (H, D) and Th-Hg Salts. New Procedures to Produce Pd Nano-Structures

    CERN Document Server

    Celani, F; Righi, E; Trenta, G; Catena, C; D’Agostaro, G; Quercia, P; Andreassi, V; Marini, P; Di Stefano, V; Nakamura, M; Mancini, A; Sona, P G; Fontana, F; Gamberale, L; Garbelli, D; Celia, E; Falcioni, F; Marchesini, M; Novaro, E; Mastromatteo, U

    2005-01-01

    Abstract They were continued, at National Institute of Nuclear Physics, Frascati National Laboratories-Italy, the systematic studies about detection of new elements, some even with isotopic composition different from natural one, after prolonged electrolysis of Pd wires. The electrolytic solution adopted is the, unusual, used from our experimental group since 1999. In short, it was a mixture of both heavy ethyl alcohol (C2H5OD at 90-95%) and water (D2O, at 10-5%), with Th salts at micromolar concentration and Hg at even lower concentration (both of spectroscopic purity). The liquid solutions, before use, were carefully vacuum distilled (and on line 100nm filtered) at low temperatures (30-40°C) and analysed by ICP-MS. The pH was kept quite mild (acidic at about 3-4). The cathode is Pd (99.9% purity) in the shape of long (60cm) and thin wires (diameter only 0.05mm). Before use, it is carefully cleaned and oxidised by Joule heating in air following a (complex) procedure from us continuously improved (since 1995...

  10. Anaerobic oxidation of Hg(0) and methylmercury formation by Desulfovibrio desulfuricans ND132

    Science.gov (United States)

    Colombo, Matthew J.; Ha, Juyoung; Reinfelder, John R.; Barkay, Tamar; Yee, Nathan

    2013-07-01

    The transformation of inorganic mercury (Hg) to methylmercury (MeHg) plays a key role in determining the amount of Hg that is bioaccumulated in aquatic food chains. An accurate knowledge of Hg methylation mechanisms is required to predict the conditions that promote MeHg production in aquatic environments. In this study, we conducted experiments to examine the oxidation and methylation of dissolved elemental mercury [Hg(0)] by the anaerobic bacterium Desulfovibrio desulfuricans ND132. Anoxic cultures of D. desulfuricans ND132 were exposed to Hg(0) in the dark, and samples were collected and analyzed for the loss of Hg(0), formation of non-purgeable Hg, and formation of MeHg over time. We found that D. desulfuricans ND132 rapidly transformed dissolved gaseous mercury into non-purgeable Hg, with bacterial cultures producing approximately 40 μg/L of non-purgeable Hg within 30 min, and as much as 800 μg/L of non-purgeable Hg after 36 h. Derivatization of the non-purgeable Hg in the cell suspensions to diethylmercury and analysis of Hg(0)-reacted D. desulfuricans ND132 cells using X-ray absorption near edge structure (XANES) spectroscopy demonstrated that cell-associated Hg was dominantly in the oxidized Hg(II) form. Spectral comparisons and linear combination fitting of the XANES spectra indicated that the oxidized Hg(II) was covalently bonded to cellular thiol functional groups. MeHg analyses revealed that D. desulfuricans ND132 produced up to 118 μg/L of methylmercury after 36 h of incubation. We found that a significant fraction of the methylated Hg was exported out of the cell and released into the culture medium. The results of this work demonstrate a previously unrecognized pathway in the mercury cycle, whereby anaerobic bacteria produce MeHg when provided with dissolved Hg(0) as their sole Hg source.

  11. Observation of intergrowth structures of Hg-1212, Hg-1223 and Hg-1234 phases in a nominal Hg-1223 ceramic superconductor

    International Nuclear Information System (INIS)

    Intergrowth structures of the Hg-1223 superconductor containing other Hg superconducting phases such as Hg-1212 and Hg-1234 were observed under a transmission electron microscope. The X-ray diffraction pattern, the resistance-temperature relationship and the a.c. magnetic susceptibility-temperature relationships indicate that the sample contains mainly Hg-1223 phase. However, scanning electron microscope and energy dispersive X-ray analysis show that the sample contains intergrowth structures. In our previous joint work, two fundamental intergrowth structures were reported. Here we report two more intergrowth structures, namely Hg-1223/(Hg-1212, Hg-1223, Hg-1234) and Hg-1223/(Hg-1223, Hg-1234). Calculation of the ratio of strain energy density Ut and the Young modulus E001 along the (001) direction of the unit cell of the Hg sample shows that the value of Ut/E001 for the first region is 1.54*10-4 and for the second is 1.56*10-3. The reason for the formation of the ill-defined mismatch region in the second intergrowth structure may be due to the relatively large strain field in the conjunction boundary of the structure. (author)

  12. Magnetic fields of HgMn stars

    CERN Document Server

    Hubrig, S; Ilyin, I; Korhonen, H; Schoeller, M; Savanov, I; Arlt, R; Castelli, F; Curto, G Lo; Briquet, M; Dall, T H

    2012-01-01

    The frequent presence of weak magnetic fields on the surface of spotted late-B stars with HgMn peculiarity in binary systems has been controversial during the two last decades. We re-analyse available spectropolarimetric material by applying the moment technique on spectral lines of inhomogeneously distributed elements separately. Furthermore, we present new determinations of the mean longitudinal magnetic field for the HgMn star HD65949 and the hotter analog of HgMn stars, the PGa star HD19400, using FORS2 installed at the VLT. We also give new measurements of the eclipsing system AR Aur with a primary star of HgMn peculiarity which were obtained with the SOFIN spectropolarimeter installed at the Nordic Optical Telescope. We downloaded from the ESO archive the publically available HARPS spectra for eight HgMn stars and one normal and one superficially normal B-type star obtained in 2010. The application of the moment technique to the HARPS and SOFIN spectra allowed us to study the presence of the longitudina...

  13. The Vein-type Zn-(Pb, Cu, As, Hg mineralization at Fedj Hassène orefield, North-Western Tunisia: Mineralogy, Trace Elements, Sulfur Isotopes and Fluid Inclusions

    Directory of Open Access Journals (Sweden)

    Bejaoui, J.

    2011-06-01

    Full Text Available The Fedj Hassène district is localized at the edge of the Tuniso-Algerian border 10 km of Ghardimaou area. It consists of a Zn-Pb vein type with minor amounts of Cu-As-Hg. The total Zn reserves are about 370.000t. The mineralization occurs within subparallel fractures to the Ain El Kohla ESE-WNW fault. Host rocks consist of limestones and marly limestones of the Middle Turonian. In the principal lode of Fedj Hassène, the mineralization occurs as vein filling of massive and brecciated brown sphalerite and minor galena ore with gangue. Other trace minerals are pyrite, chalcopyrite, orpiment, realgar, smithsonite and cerussite. LA-ICP-MS analyses in sphalerites show mean contents of 0,84 wt% Fe, 0,14 wt% Cd and 0,02 wt% Mn Ore. Fluid inclusions study in calcite and sphalerite reveals one mineralizing fluid characterized by an average salinity 23% wt NaCl with decreasing homogenisation temperature. In fact the temperature shows decrease from sphalerite to calcite. The fluid density that corresponds to trapping pressure ranges between 1.00 g/cm3 and 1.11 g/cm3 and pressure close to 200 bars. Microthermometric data in fluid inclusion hosted by gangue mineral presented by calcite show an average temperature of formation around 194°C. These inclusions homogenized to the liquid phase between 156°C and 210°C and salinities values ranging from 22 to 28 wt% NaCl and an average around 23% wt NaCl. The δ34S (VCDT values of sphalerite are in the range of + 4,6‰ to 6,4‰ (average=5,6‰. Thermochemical reduction of Triassic sulfate by reaction with hydro-carbons is the most probable source for the heavy and the narrow range of the ?34S values. Mineralogical, geochemical of trace elements, fluid inclusions and sulfur isotopes studies allow to include the vein-type ore field of Fedj Hassène in the polymetallic (Pb-Zn-As-Hg vein mineralization of the nappe zone in northern Tunisia and north eastern Algeria

  14. Methylation of Hg downstream from the Bonanza Hg mine, Oregon

    Science.gov (United States)

    Gray, John E.; Hines, Mark E.; Krabbenhoft, David P.; Thoms, Bryn

    2012-01-01

    Speciation of Hg and conversion to methyl-Hg were evaluated in stream sediment, stream water, and aquatic snails collected downstream from the Bonanza Hg mine, Oregon. Total production from the Bonanza mine was >1360t of Hg, during mining from the late 1800s to 1960, ranking it as an intermediate sized Hg mine on an international scale. The primary objective of this study was to evaluate the distribution, transport, and methylation of Hg downstream from a Hg mine in a coastal temperate climatic zone. Data shown here for methyl-Hg, a neurotoxin hazardous to humans, are the first reported for sediment and water from this area. Stream sediment collected from Foster Creek flowing downstream from the Bonanza mine contained elevated Hg concentrations that ranged from 590 to 71,000ng/g, all of which (except the most distal sample) exceeded the probable effect concentration (PEC) of 1060ng/g, the Hg concentration above which harmful effects are likely to be observed in sediment-dwelling organisms. Concentrations of methyl-Hg in stream sediment collected from Foster Creek varied from 11 to 62ng/g and were highly elevated compared to regional baseline concentrations (0.11-0.82ng/g) established in this study. Methyl-Hg concentrations in stream sediment collected in this study showed a significant correlation with total organic C (TOC, R2=0.62), generally indicating increased methyl-Hg formation with increasing TOC in sediment. Isotopic-tracer methods indicated that several samples of Foster Creek sediment exhibited high rates of Hg-methylation. Concentrations of Hg in water collected downstream from the mine varied from 17 to 270ng/L and were also elevated compared to baselines, but all were below the 770ng/L Hg standard recommended by the USEPA to protect against chronic effects to aquatic wildlife. Concentrations of methyl-Hg in the water collected from Foster Creek ranged from 0.17 to 1.8ng/L, which were elevated compared to regional baseline sites upstream and downstream

  15. Study on the application of magnesium oxide adsorptive compound to preconcentrate trace elements (As, Cu, Co, Cr, Hg, Mn, Sb and Zn) in high salt water and neutron activation analysis

    International Nuclear Information System (INIS)

    The project presents preconcentration neutron activation analysis techniques for determination of trace metals (As, Co, Cr Cu, Hg, Mn, Sb and Zn) in high salt water by adsorption of trace metals on magnesium oxide. Precipitate is collected on 0.45 μm membrane filters and irradiated in pneumatic rabit system and Lazy Susan facility at flux 5.1012 n/cm2.sec for As, Cu, Mn and 2.1012 n/cm2.sec for Hg, Sb, Cr, Co and Zn. The radioactivities of 76As, 60Co, 64Cu, 51Cr, 203Hg, 56Mn, 124Sb and 65Zn were measured. 76As, 60Co, 64Cu, 51Cr, 203Hg, 56Mn, 124Sb and 65Zn radio traces were used to establish optimum conditions and to evaluate the chemical yield. Detection limits of this method are 0.019, 0.006, 0.044, 0.058, 0.021, 0.027, 0.012 and 0.094 μg of As, Co, Cr, Cu, Hg, Mn, Sb and Zn respectively. (author)

  16. Hg-Mask Coronagraph

    Science.gov (United States)

    Bourget, P.; Veiga, C. H.; Vieira Martins, R.; Assus, P.; Colas, F.

    In order to optimize the occulting process of a Lyot coronagraph and to provide a high dynamic range imaging, a new kind of occulting disk has been developed at the National Observatory of Rio de Janeiro. A mercury (Hg) drop glued onto an optical window by molecular cohesion and compressed by a pellicle film is used as the occulting disk. The minimum of the superficial tension potential function provides an optical precision (lambda/100) of the toric free surface of the mercury. This process provides a size control for the adaptation to the seeing conditions and to the apparent diameter of a resolved object, and in the case of adaptive optics, to the Airy diameter fraction needed. The occultation is a three dimensional process near the focal plane on the toric free surface that provides an apodization of the occultation. The Hg-Mask coronagraph has been projected for astrometric observations of faint satellites near to Jovian planets and works since 2000 at the 1.6 m telescope of the Pico dos Dias Observatory (OPD - Brazil).

  17. Chalcophile element (Ni, Cu, PGE, and Au) variations in the Tamarack magmatic sulfide deposit in the Midcontinent Rift System: implications for dynamic ore-forming processes

    Science.gov (United States)

    Taranovic, Valentina; Ripley, Edward M.; Li, Chusi; Rossell, Dean

    2016-03-01

    The Tamarack magmatic sulfide deposit is hosted by the Tamarack Intrusive Complex (1105.6 ± 1.2 Ma) in the Midcontinent Rift System. The most important sulfide mineralization in the Complex occurs in the northern part, which consists of two separate intrusive units: an early funnel-shaped layered peridotite body containing relatively fine-grained olivine (referred to as the FGO Intrusion) at the top, and a late gabbro-troctolite-peridotite dike-like body containing relatively coarse-grained olivine (referred to as the CGO Intrusion) at the bottom. Disseminated, net-textured, and massive sulfides occur in the base of the FGO Intrusion as well as in the upper part of the CGO Intrusion. The widest part of the CGO Intrusion also hosts a large semi-massive (net-textured) sulfide ore body locally surrounded by disseminated sulfide mineralization. Small massive sulfide veins occur in the footwall of the FGO Intrusion and in the wall rocks of the CGO dike. The sulfide mineralization is predominantly composed of pyrrhotite, pentlandite, and chalcopyrite, plus minor magnetite. Pyrrhotite containing the highest Ni and Co contents occurs in the FGO disseminated sulfides and in the CGO semi-massive sulfide ores, respectively. The most important platinum-group minerals associated with the base metal sulfides are sperrylite (PtAs2), sudburyite (PdSb), and michenerite (PdBiTe). Nickel shows a strong positive correlation with S in all types of sulfide mineralization, and Cu shows a strong positive correlation with S in the disseminated sulfide mineralization. At a given S content, the concentrations of Pt, Pd, and Au in the CGO disseminated sulfides are significantly higher than those in the FGO disseminated sulfides. The semi-massive sulfide ores are characterized by significantly higher IPGE (Ir, Os, Ru, and Rh) concentrations than most of the massive sulfide ores. With few exceptions, all of the various textural types of sulfide mineralization collectively show a good positive correlation between Pt and Pd, and between individual IPGE. At a given Pt or Pd content, however, the semi-massive sulfide ores have higher IPGE contents than the disseminated sulfide samples. Modeling results show that the variations in PGE tenors (metals in recalculated 100 % sulfide) in the Tamarack magmatic sulfide deposit are mainly controlled by variable R factors (magma/sulfide-liquid mass ratios) during sulfide-liquid segregation and subsequent monosulfide solid solution (MSS) fractionation during cooling. The initial contents of Ir, Pt, and Pd in the parental magma, estimated from the metal tenors of the disseminated sulfides, are 0.2, 2, and 1.8 ppb, respectively, which are ˜1/5 of the values for the PGE-undepleted primitive basalts of the Midcontinent Rift System. The variations of PGE tenors in the semi-massive and massive sulfide ores can be explained by MSS fractional crystallization from sulfide liquids. Extreme variations in the PGE contents of the massive sulfides may also in part reflect metal mobility during post-crystallization hydrothermal processes. The higher PGE tenors for the disseminated sulfides in the CGO dike relative to those in the FGO Intrusion are consistent with formation in a dynamic conduit where the early sulfide liquids left in the conduit by the FGO magma were subsequently upgraded by the subsequent surge of the CGO magma. The relatively low PGE tenors for the semi-massive and massive sulfides can be explained by lack of such an upgrading process for the sulfide due to their distal locations in a migrating conduit.

  18. Natural Hg isotopic composition of different Hg compounds in mammal tissues as a proxy for in vivo breakdown of toxic methylmercury.

    Science.gov (United States)

    Perrot, Vincent; Masbou, Jeremy; Pastukhov, Mikhail V; Epov, Vladimir N; Point, David; Bérail, Sylvain; Becker, Paul R; Sonke, Jeroen E; Amouroux, David

    2016-02-01

    In the last decade, specific attention has been paid to total mercury (HgT) stable isotopic composition, especially in natural samples such as aquatic organisms, due to its potential to track the cycle of this toxic element in the environment. Here, we investigated Hg Compound Specific stable Isotopic Composition (CSIC) of natural inorganic Hg (iHg) and methylmercury (MMHg) in various tissues of aquatic mammals (Beluga whale from the Arctic marine environment and seals from the freshwater lake Baikal, Russia). In seals' organs the variation in mass dependent fractionation (MDF, δ(202)Hg) for total Hg was significantly correlated to the respective fraction of iHg and MMHg compounds, with MMHg being enriched by ∼ 3‰ in heavier isotopes relative to iHg. On the other hand, we observe insignificant variation in Hg mass independent isotope fractionation (MIF, Δ(199)Hg) among iHg and MMHg in all organs for the same mammal species and MMHg in prey items. MIF signatures suggest that both MMHg and iHg in aquatic mammals have the same origin (i.e., MMHg from food), and are representative of Hg photochemistry in the water column of the mammal ecosystem. MDF signatures of Hg compounds indicate that MMHg is demethylated in vivo before being stored in the muscle, and the iHg formed is stored in the liver, and to a lesser extent in the kidney, before excretion. Thus, Hg CSIC analysis in mammals can be a powerful tool for tracing the metabolic response to Hg exposure. PMID:26680232

  19. 46 CFR 53.10-3 - Inspection and tests (modifies HG-500 through HG-540).

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Inspection and tests (modifies HG-500 through HG-540... tests (modifies HG-500 through HG-540). (a) The inspections required by HG-500 through HG-540 must be performed by the “Authorized Inspector” as defined in HG-515 of section IV of the ASME Boiler and...

  20. HCN Producing Bacteria Enable Sensing Of Non-Bioavailable Hg Species by the Whole Cell Biosensor

    Science.gov (United States)

    Horvat, M.; Rijavec, T.; Koron, N.; Lapanje, A.

    2015-12-01

    Bacteria play an important role in Hg transformation reactions. The production of cyanide (HCN) and other secondary metabolites seems to be key elements involved in these transformations. Current hypotheses link the role of HCN production to growth inhibition of nonHCN producing competitor organisms (role of an antimicrobial agent). Our past investigations showed that HCN production did not correlate with antimicrobial activity and since pK value of HCN is very high (pK = 9,21), it can be expected that most of the produced HCN is removed from the microenvironment. This way, the expected inhibitory concentrations can hardly be reached. Accordingly, we proposed a new concept, where the ability of complexation of transient metals by HCN served as a regulation process for the accessibility of micro-elements. In our study, we focused on the presence of HCN producing bacteria and carried it out in the Hg contaminated environment connected to the Idrija Mercury Mine, Slovenia. We characterised the isolates according to the presence of Hg resistance (HgR), level of HCN production and genetic similarities. In laboratory setups, using our merR whole cell based biosensor, we determined the transformation of low bioavailable Hg0 and HgS forms into bioavailable Hg by these HCN producing bacteria. We observed that HgR strains producing HCN had the highest impact on increased Hg bioavailability. In the proposed ecological strategy HgR HCN producing bacteria increase their competitive edge over non-HgR competitors through the increase of Hg toxicity. Due to their activity, Hg is made available to other organisms as well and thus enters into the ecosystem. Finally, using some of the characteristics of bacteria (e.g. Hg resistance genetic elements), we developed a fully automated sensing approach, combining biosensorics and mechatronics, to measure the bioavailability of Hg in situ.

  1. Assessment of soil contamination by potentially toxic trace elements (PTSD) (As, Cd, Cu, Hg, Pb, Zn) in a lower plain of the Hron River according to Law no. 219/2008 Coll., by geo-accumulation index, anthropogenic factor and Tomlinson index

    International Nuclear Information System (INIS)

    Soil contamination by different PTSD may have different geogenic and anthropogenic origin and occurs in all countries of the world. The aim of this paper is to evaluate the soils contamination of a lower plain of the Hron River. This paper used the results of the thesis Soil contamination of the Hron River floodplain by trace elements (As, Cd, Cu, Hg, Pb, Zn) [1]. Soil contamination was evaluated by: Act. 219/2008 Coll. on the protection and use of agricultural land, by anthropogenic factor (AF), geo-accumulation index (IgeoE) and Tomlinson index - the index of the pollution load (PLI). (author)

  2. Mercury (Hg) accumulation in terrestrial carbon (C) reservoirs: magnitude, spatial patterns, fate upon C losses, and implications of global change

    Science.gov (United States)

    Obrist, D.; Johnson, D. W.; Lindberg, S. E.; Luo, Y.

    2012-04-01

    Terrestrial ecosystems are strong natural reservoirs that retain the bulk of atmospheric Hg deposition. As a result, a long-term legacy of past and present Hg pollution is sequestered in surface litter and soil pools. Hg shows a particular affinity to—and hence tends to accumulate in—terrestrial organic C. We present a summary of a comprehensive five-year investigation where we quantified: (i) relationships between Hg and C across 14 forests sites to assess the affinity of Hg to C accumulation across spatial scales; (ii) the degree to which C determines net retention and spatial accumulation of Hg; (iii) the fate of Hg upon losses of C, including losses though wildfires and mineralization; (iv) the coupling of gaseous Hg losses to CO2 respiration; and (v) the potential sensitivity of climate-change induced changes in C on terrestrial Hg sequestration. Results show that continental-scale spatial distribution of Hg in soils and litter is strongly related to C, and that old terrestrial C pools (as determined by C/N ratios) are particularly prone to Hg enrichment. The correlation of Hg and C is likely responsible for increasing Hg levels (concentrations and pools of total Hg, as well as methylated Hg) with higher latitude, which we attribute to a legacy of Hg sequestration in C-rich layers of northern ecosystems. Experimental studies and field observations to address fate of Hg sequestered in organic C show that: (i) fires leads to up-to-complete Hg losses in either gaseous elemental or particulate-bound form; (ii) litter decomposition also leads to evasion losses of Hg in the range of 50% of initial Hg, but little Hg is subject to runoff as dissolved Hg; (iii) soils effectively retain Hg with only about 3% of Hg subject to volatilization upon C loss during respiration; (iv) no links between CO2 and gaseous Hg concentrations are observed in soil depth profiles in the field, indicating that fate and movement of gaseous Hg is decoupled from that of CO2. We calculate

  3. Metallophilic HgII...HgII interactions in nucleic acids

    Czech Academy of Sciences Publication Activity Database

    Benda, Ladislav; Tanaka, Y.; Sychrovský, Vladimír; Straka, Michal

    Praha: Matfyzpress, 2011 - (Burda, J.). s. 62-62 ISBN 978-80-7378-180-4. [Modeling Interactions in Biomolecules /5./. 04.09.2011-09.09.2011, Kutná Hora] R&D Projects: GA ČR GA203/09/2037; GA ČR GAP205/10/0228 Grant ostatní: European Reintegration Grant(XE) 230955 Institutional research plan: CEZ:AV0Z40550506 Keywords : metallophilic HgII...HgII interactions * metallophilic interactions * base stacking * nucleic acids Subject RIV: CF - Physical ; Theoretical Chemistry

  4. Contrasting food web factor and body size relationships with Hg and Se concentrations in marine biota.

    Science.gov (United States)

    Karimi, Roxanne; Frisk, Michael; Fisher, Nicholas S

    2013-01-01

    Marine fish and shellfish are primary sources of human exposure to mercury, a potentially toxic metal, and selenium, an essential element that may protect against mercury bioaccumulation and toxicity. Yet we lack a thorough understanding of Hg and Se patterns in common marine taxa, particularly those that are commercially important, and how food web and body size factors differ in their influence on Hg and Se patterns. We compared Hg and Se content among marine fish and invertebrate taxa collected from Long Island, NY, and examined associations between Hg, Se, body length, trophic level (measured by δ(15)N) and degree of pelagic feeding (measured by δ(13)C). Finfish, particularly shark, had high Hg content whereas bivalves generally had high Se content. Both taxonomic differences and variability were larger for Hg than Se, and Hg content explained most of the variation in Hg:Se molar ratios among taxa. Finally, Hg was more strongly associated with length and trophic level across taxa than Se, consistent with a greater degree of Hg bioaccumulation in the body over time, and biomagnification through the food web, respectively. Overall, our findings indicate distinct taxonomic and ecological Hg and Se patterns in commercially important marine biota, and these patterns have nutritional and toxicological implications for seafood-consuming wildlife and humans. PMID:24019976

  5. Contrasting food web factor and body size relationships with Hg and Se concentrations in marine biota.

    Directory of Open Access Journals (Sweden)

    Roxanne Karimi

    Full Text Available Marine fish and shellfish are primary sources of human exposure to mercury, a potentially toxic metal, and selenium, an essential element that may protect against mercury bioaccumulation and toxicity. Yet we lack a thorough understanding of Hg and Se patterns in common marine taxa, particularly those that are commercially important, and how food web and body size factors differ in their influence on Hg and Se patterns. We compared Hg and Se content among marine fish and invertebrate taxa collected from Long Island, NY, and examined associations between Hg, Se, body length, trophic level (measured by δ(15N and degree of pelagic feeding (measured by δ(13C. Finfish, particularly shark, had high Hg content whereas bivalves generally had high Se content. Both taxonomic differences and variability were larger for Hg than Se, and Hg content explained most of the variation in Hg:Se molar ratios among taxa. Finally, Hg was more strongly associated with length and trophic level across taxa than Se, consistent with a greater degree of Hg bioaccumulation in the body over time, and biomagnification through the food web, respectively. Overall, our findings indicate distinct taxonomic and ecological Hg and Se patterns in commercially important marine biota, and these patterns have nutritional and toxicological implications for seafood-consuming wildlife and humans.

  6. 40 CFR 60.4112 - Changing Hg designated representative and alternate Hg designated representative; changes in...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Changing Hg designated representative and alternate Hg designated representative; changes in owners and operators. 60.4112 Section 60.4112... Generating Units Hg Designated Representative for Hg Budget Sources § 60.4112 Changing Hg...

  7. Thermodynamics of reactions of ClHg and BrHg radicals with atmospherically abundant free radicals

    Directory of Open Access Journals (Sweden)

    T. S. Dibble

    2012-07-01

    Full Text Available Quantum calculations are used to determine the stability of reactive gaseous mercury (Hg(II compounds likely to be formed in the Br-initiated oxidation of gaseous elemental mercury (Hg(0. Due to the absence of any evidence, current models neglect the possible reaction of BrHg• with abundant radicals such as NO, NO2, HO2, ClO, or BrO. The present work demonstrates that BrHg• forms stable compounds, BrHgY, with all of these radicals except NO. Additional calculations on the analogous ClHgY compounds reveal that the strength of the XHg-Y bond (for X=Cl, Br varies little with the identity of the halogen. Calculations further suggest that ClO, BrO, and NO3 do not form strong bonds with Hg(0, and cannot initiate Hg(0 oxidation in the gas phase. The theoretical approach is validated by comparison to published data on HgX2 compounds, both from experiments and highly refined quantum chemical calculations. Quantum calculations on the stability of the anions of XHgY are carried out in order to aid future laboratory studies aimed at molecular-level characterization of gaseous Hg(II compounds. Spectroscopic data on BrHg• are analyzed to determine the equilibrium constant for its formation, and BrHg• is determined to be much less stable than previously estimated. An expression is presented for the rate constant for BrHg• dissociation.

  8. The new barium zinc mercurides Ba3ZnHg10 and BaZn0.6Hg3.4 – Synthesis, crystal and electronic structure

    International Nuclear Information System (INIS)

    The title compounds Ba3ZnHg10 and BaZn0.6Hg3.4 were synthesized from stoichiometric ratios of the elements in Ta crucibles. Their crystal structures, which both represent new structure types, have been determined using single crystal X-ray data. The structure of Ba3ZnHg10 (orthorhombic, oP28, space group Pmmn, a=701.2(3), b=1706.9(8), c=627.3(3)pm, Z=2, R1=0.0657) contains folded 44 Hg nets, where the meshes form the bases of flat rectangular pyramids resembling the structure of BaAl4. The flat pyramids are connected via Hg–Zn/Hg bonds, leaving large channels at the folds, in which Ba(1) and Hg(2) atoms alternate. Whereas the remaining Hg/Zn atoms form a covalent 3D network of three- to five-bonded atoms with short M–M distances (273–301 pm; CN 9–11), the Hg(2) atoms in the channels adopt a comparatively large coordination number of 12 and increased distances (317–348 pm) to their Zn/Hg neighbours. In the structure of BaZn0.6Hg3.4 (cubic, cI320, space group I4¯3d, a=2025.50(7) pm, Z=64, R1=0.0440), with a chemical composition not much different from that of Ba3ZnHg10, the Zn/Hg atoms of the mixed positions M(1/2) are arranged in an slightly distorted primitive cubic lattice with a 4×4×4 subcell relation to the unit cell. The 24 of the originating 64 cubes contain planar cis tetramers Hg(5,6)4 with Hg in a nearly trigonal planar or tetrahedral coordination. In another 24 of the small cubes, two opposing faces are decorated by Hg(3,4)2 dumbbells, two by Ba(2) atoms respectively. The third type of small cubes are centered by Ba(1) atoms only. The complex 3D polyanionic Hg/Zn network thus formed is compared with the Hg partial structure in Rb3Hg20 applying a group-subgroup relation. Despite their different overall structures, the connectivity of the negatively charged Hg atoms, the rather metallic Zn bonding characteristic (as obtained from FP-LAPW band structure calculations) and the coordination number of 16 for all Ba cations relate the two title

  9. High-resolution Hg Chemostratigraphy

    DEFF Research Database (Denmark)

    Sial, Alcides N.; Chen, J.; Lacerda, L.D.;

    2014-01-01

    There is a renewed interest in volcanism as the major trigger for dramatic climatic changes at the Cretaceous–Paleogene transition (KTB), which were accompanied by a decrease in biodiversity and mass extinction. We have used Hg contents as proxy for volcanic activity at the classical localities o...

  10. Mercury methylation and reduction potentials in marine water: An improved methodology using 197Hg radiotracer

    International Nuclear Information System (INIS)

    A highly sensitive laboratory methodology for simultaneous determination of methylation and reduction of spiked inorganic mercury (Hg2+) in marine water labelled with high specific activity radiotracer (197Hg prepared from enriched 196Hg stable isotope) was developed. A conventional extraction protocol for methylmercury (CH3Hg+) was modified in order to significantly reduce the partitioning of interfering labelled Hg2+ into the final extract, thus allowing the detection of as little as 0.1% of the Hg2+ spike transformed to labelled CH3Hg+. The efficiency of the modified CH3Hg+ extraction procedure was assessed by radiolabelled CH3Hg+ spikes corresponding to concentrations of methylmercury between 0.05 and 4 ng L−1. The recoveries were 73.0±6.0% and 77.5±3.9% for marine and MilliQ water, respectively. The reduction potential was assessed by purging and trapping the radiolabelled elemental Hg in a permanganate solution. The method allows detection of the reduction of as little as 0.001% of labelled Hg2+ spiked to natural waters. To our knowledge, the optimised methodology is among the most sensitive available to study the Hg methylation and reduction potential, therefore allowing experiments to be done at spikes close to natural levels (1–10 ng L−1). - Highlights: ► Inorganic mercury methylation and reduction in marine water were studied. ► High specific activity 197Hg was used to label Hg2+ spikes at natural levels. ► Methylmercury extraction had 73% efficiency for 0.05–4 ng L−1 levels. ► High sensibility to assess methylation potentials, below 0.1% of the spike. ► High sensibility also for reduction potentials, as low as 0.001% of the spike.

  11. Hg diffusion in books of XVIII and XIX centuries by synchrotron microprobe

    International Nuclear Information System (INIS)

    The pigment vermilion (HgS) was used to color the fore edge, tail and head of books. Dissemination and quantification of Hg present in the ink used to color books from XVIII and XIX centuries are reported. Mercury is a very toxic element for the human body, therefore it is extremely important to know whether Hg tends to disseminate throughout the paper or stays confined to the borders of the books with less danger for readers. Synchrotron X-ray microprobe was used to evaluate Hg dissemination from the border to the centre of the paper sheet. The diffusion pattern of Hg was compared with the results obtained by a portable X-ray fluorescence spectrometer and mean quantitative calculations were obtained by a stationary X-ray fluorescence system with triaxial geometry. The results showed high concentrations of Hg in the external regions, but no diffusion was observed for the inner parts of the paper.

  12. Theranostic mercury: 197(m)Hg with high specific activity for imaging and therapy

    International Nuclear Information System (INIS)

    The no carrier added (NCA) radionuclide 197(m)Hg is accessible through proton induced nuclear reactions on gold. The decay properties of both simultaneous produced nuclear isomers 197mHg and 197Hg like convenient half life, low energy gamma radiations for imaging, Auger and conversion electrons for therapy are combined with unique chemical and physical properties of mercury and its compounds. Gold as a monoisotopic element has a natural abundance of 100% 197Au superseding expensive enrichment for the target material. Additionally, the high thermal conductivity of gold enables high beam current irradiations. For separation of target material a liquid–liquid extraction method was applied. - Highlights: • No carrier added 197(m)Hg. • 197(m)Hg promising for therapeutic application. • 197(m)Hg for imaging

  13. Iminocoumarin-based Hg(II) Ion Probe

    International Nuclear Information System (INIS)

    The design and synthesis of new chemosensors for heavy and transition metal ions (HTM) has been an important subject in the field of supramolecular chemistry due to their fundamental role in biological, environmental, and chemical processes. Particularly, the recognition and detection of Hg2+ are of growing interest because the Hg2+ is considered highly noxious elements. Many analytical methods have been applied for this purpose including atomic absorption spectrometry (AAS), ion selective electrodes (ISE), and flame photometry. In addition, for the detection of HTM (heavy and transition metal), colorimetric sensors have also gained interest. The colorimetric sensors have considerable advantages over other molecular sensors because they do not require the use of costly equipment such as spectrophotometers, ISE, or cyclic voltameters. So, to develop simple-to-use and naked-eye diagnostic tool, great efforts have been made for the design and synthesis of selective chromogenic sensors for Hg2+

  14. Spectroscopic variability and magnetic fields of HgMn stars

    CERN Document Server

    Hubrig, S; Ilyin, I; Korhonen, H; Savanov, I S; Dall, T; Schoeller, M; Cowley, C R; Briquet, M; Arlt, R

    2011-01-01

    The discovery of exotic abundances, chemical inhomogeneities, and weak magnetic fields on the surface of late B-type primaries in spectroscopic binaries has important implications not only for our understanding of the formation mechanisms of stars with Hg and Mn peculiarities themselves, but also for the general understanding of B-type star formation in binary systems. The origin of the abundance anomalies observed in late B-type stars with HgMn peculiarity is still poorly understood. The connection between HgMn peculiarity and membership in binary and multiple systems is supported by our observations during the last decade. The important result achieved in our studies of a large sample of HgMn stars is the finding that most HgMn stars exhibit spectral variability of various chemical elements, proving that the presence of an inhomogeneous distribution on the surface of these stars is a rather common characteristic and not a rare phenomenon. Further, in the studied systems, we found that all components are che...

  15. Changements de phases durant l'électrolyse des systèmes Hg-Tl, Hg-Sn, Hg-Pb et Hg-Zn

    OpenAIRE

    Dumas, Jean-Pierre; Bougarfa, L.; Bensaid, J.

    1984-01-01

    On utilise la méthode électrochimique de détection des transformations de phases dans les amalgames au cours d'électrolyse monotherme décrite dans un article précédent [2] pour l'étude des systèmes Hg-Tl, Hg-Sn, Hg-Pb et Hg-Zn. Dans les systèmes Hg-Pb et Hg-Zn la cristallisation se produit dès que la fraction molaire de saturation est atteinte mais des phases liquides métastables sont observées dans les systèmes Hg-Tl et Hg-Sn. A 25 °C, la rupture de métastabilité a lieu à des fractions molai...

  16. Dipole Bands in 196Hg

    International Nuclear Information System (INIS)

    High spin states in 196Hg have been populated in the 198Pt(α,6n) reaction at 65 MeV and the level scheme has been extended. A new dipole band has been observed and a previously observed dipole has been confirmed. Excitation energies, spins and parities of these bands were determined from DCO ratio and linear polarization measurements. Possible quasiparticle excitations responsible for these structures are discussed.

  17. Mercury isotope signatures as tracers for Hg cycling at the New Idria Hg mine.

    Science.gov (United States)

    Wiederhold, Jan G; Smith, Robin S; Siebner, Hagar; Jew, Adam D; Brown, Gordon E; Bourdon, Bernard; Kretzschmar, Ruben

    2013-06-18

    Mass-dependent fractionation (MDF) and mass-independent fractionation (MIF) of Hg isotopes provides a new tool for tracing Hg in contaminated environments such as mining sites, which represent major point sources of Hg pollution into surrounding ecosystems. Here, we present Hg isotope ratios of unroasted ore waste, calcine (roasted ore), and poplar leaves collected at a closed Hg mine (New Idria, CA, U.S.A.). Unroasted ore waste was isotopically uniform with δ(202)Hg values from -0.09 to 0.16‰ (± 0.10‰, 2 SD), close to the estimated initial composition of the HgS ore (-0.26‰). In contrast, calcine samples exhibited variable δ(202)Hg values ranging from -1.91‰ to +2.10‰. Small MIF signatures in the calcine were consistent with nuclear volume fractionation of Hg isotopes during or after the roasting process. The poplar leaves exhibited negative MDF (-3.18 to -1.22‰) and small positive MIF values (Δ(199)Hg of 0.02 to 0.21‰). Sequential extractions combined with Hg isotope analysis revealed higher δ(202)Hg values for the more soluble Hg pools in calcines compared with residual HgS phases. Our data provide novel insights into possible in situ transformations of Hg phases and suggest that isotopically heavy secondary Hg phases were formed in the calcine, which will influence the isotope composition of Hg leached from the site. PMID:23662941

  18. Total Hg and methyl Hg distribution in sediments of selected Louisiana water bodies.

    Science.gov (United States)

    Delaune, Ronald D; Gambrell, Robert P; Devai, Istvan; Jugsujinda, Aroon; Kongchum, Manoch

    2009-05-01

    Sediment samples (543) collected from selected Louisiana streams and lakes were analyzed for total Hg and methyl Hg content. The average total Hg content among 543 samples was 92.3 +/- 95.1 microg kg(-1). The average methyl Hg content in the samples was 0.68 +/- 0.80 microg kg(-1). Methyl Hg accounted for an average of 0.73% of the total Hg in sediment. Linear regression analysis of total Hg versus methyl Hg content of the sediment showed methyl Hg content was significantly correlated to total Hg content of sediment (P > 0.01, n = 537) and sediment organic matter content. (P > 0.01, n = 536) Methyl Hg was also positively correlated to clay (P > 0.01, n = 537) and inversely correlated to sand content of sediment (P > 0.01, n = 537). Total Hg and methyl Hg content in these sediments was within the normal range reported elsewhere indicating no significant industrial or municipal Hg contamination. A comparison of selected water bodies with fishing advisories showed no relationship to total Hg and methyl Hg in sediment. PMID:19337918

  19. 46 CFR 53.12-1 - General (modifies HG-600 through HG-640).

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false General (modifies HG-600 through HG-640). 53.12-1... HEATING BOILERS Instruments, Fittings, and Controls (Article 6) § 53.12-1 General (modifies HG-600 through HG-640). (a) The instruments, fittings and controls for heating boilers shall be as indicated in...

  20. Detection Feasibility of Magnetic Fields and HG Abundances in HgMn Stars

    Science.gov (United States)

    Takada-Hidai, M.; Sakaue, A.; Kotake, J.

    We analyzed two Fe II lines at 6147.7 AA and 6149.2 AA observed in 14 HgMn stars with the purpose to examine the feasibility of detecting magnetic fields in HgMn stars based on Mathys' empirical relation between the strengths of the Fe II lines and magnetic fields (Mathys 1990, A&A 232, 151). Takada-Hidai & Jugaku (1992, PASP 104, 106) found that the Fe II 6149 AA is strongly blended with the Hg II 6149.5 AA line in the typical HgMn star mu Lep. To investigate the blending effect of the Hg II line, we measured the strengths of Fe II lines in the sample stars with the Hg abundances of 4 < log Hg < 7 and obtained Hg abundaces from the blending Hg II lines. Most of the resulting Hg abundances were found to agree with the previously determined values within about 0.6 dex. We also found, from a comparison between the strengths of Fe II lines with Hg abundances, that the blending effect of the Hg II line seems to be negligible for the Hg abundances of about < 5 dex, and therefore magnetic fields may possibly be detected with Mathys' empirical relation in case of HgMn stars with such Hg abundances as < 5 dex.

  1. Four new HgMn stars: HD 18104, HD 30085, HD 32867, HD 53588

    CERN Document Server

    Monier, R; Royer, F

    2015-01-01

    We have detected four new HgMn stars, while monitoring a sample of apparently slowly rotating superficially normal bright late B and early A stars in the northern hemisphere. Important classification lines of Hg II and Mn II are found as conspicuous features in the high resolution SOPHIE spectra of these stars (R = 75000). Several lines of Hg II, Mn II and Fe II have been synthesized using model atmospheres and the spectrum synthesis code SYNSPEC48 including hyperfine structure of various isotopes when relevant. These synthetic spectra have been compared to high resolution high signal-to-noise observations of these stars in order to derive abundances of these key elements. The four stars are found to have distinct enhancements of Hg and Mn which show that these stars are not superficially normal B and A stars, but actually are new HgMn stars and should reclassified as such.

  2. Speciation, Characterization, And Mobility Of As, Se, and Hg In Flue Gas Desulphurization Residues

    Science.gov (United States)

    Flue gas from coal combustion contains significant amounts of volatile elements, such as arsenic (As), selenium (Se) and mercury (Hg), which could lead to serious environmental health risks. The capture of these toxic elements in the scrubber with a flue gas desulphurization (FGD...

  3. PENCEMARAN LOGAM BERAT MERKURI (Hg PADA AIRTANAH

    Directory of Open Access Journals (Sweden)

    Thomas Triadi Putranto

    2012-02-01

    Full Text Available The earth consists largely of water because the land area is smaller than the ocean. Human beings on this earthcan not escape the need for water. Water is the main requirement for the process of life on the earth.Relatively clean water that is coveted by men, whether for purposes of daily life, for industrial purposes, for thecleanliness of city sanitation, as well as for agricultural purposes and so forth. Heavy metal pollution is a veryserious issue to be handled, because of adverse environmental and ecosystem in general. Heavy metallic elementis the element which has a density of more than 5 gr/cm3. Hg has a density of 13.55 gr/cm3. Disaster is anoutbreak of Minamata mercury poisoning in people who eat fish contaminated by mercury in Minamata Japan,and this event is known as Minamata Disease. Efforts to tackle the heavy metal pollution can actually be doneusing a chemical process or by microorganism such as microbes and bacteria.

  4. Chemical stabilization and high pressure synthesis of Ba-free Hg-based superconductors, (Hg,M)Sr{sub 2}Ca{sub n-1}Cu{sub n}O{sub y}(N=1{approximately}3)

    Energy Technology Data Exchange (ETDEWEB)

    Kishio, K. [Univ. of Tokyo (Japan)]|[Kyoto Univ. (Japan); Shimoyama, J.; Hahakura, S. [Univ. of Tokyo (Japan)] [and others

    1994-12-31

    A homologous series of new Hg-based HTSC compounds, (Hg,M)Sr{sub 2}Ca{sub n-1}Cu{sub n}O{sub y} with n=1 to 3, have been synthesized. The stabilization of the pure phases have been accomplished by chemical doping of third elements such as M=Cr, Mo and Re. While the Hg1201(n=1) phase was readily obtained in this way, it was necessary to simultaneously dope Y into the Ca site to stabilize the Hg1212(n=2) phase. On the other hand, single-phase Y-free Hg1212(n=2) and Hg1223(n=3) samples were synthesized only under a high pressure of 6 GPa. In sharp contrast to the Ba-containing compounds, all the samples prepared in the present study have been quite stable during the synthesis and no deterioration in air has been observed after the preparation.

  5. Mercury methylation and reduction potentials in marine water: An improved methodology using {sup 197}Hg radiotracer

    Energy Technology Data Exchange (ETDEWEB)

    Koron, Neza [National Institute of Biology, Marine Biology Station, Fornace 41, 6330 Piran (Slovenia); Bratkic, Arne [Department of Environmental Sciences, ' Jozef Stefan' Institute, Jamova 39, 1000 Ljubljana (Slovenia); Ribeiro Guevara, Sergio, E-mail: ribeiro@cab.cnea.gov.ar [Laboratorio de Analisis por Activacion Neutronica, Centro Atomico Bariloche, Av. Bustillo km 9.5, 8400 Bariloche (Argentina); Vahcic, Mitja; Horvat, Milena [Department of Environmental Sciences, ' Jozef Stefan' Institute, Jamova 39, 1000 Ljubljana (Slovenia)

    2012-01-15

    A highly sensitive laboratory methodology for simultaneous determination of methylation and reduction of spiked inorganic mercury (Hg{sup 2+}) in marine water labelled with high specific activity radiotracer ({sup 197}Hg prepared from enriched {sup 196}Hg stable isotope) was developed. A conventional extraction protocol for methylmercury (CH{sub 3}Hg{sup +}) was modified in order to significantly reduce the partitioning of interfering labelled Hg{sup 2+} into the final extract, thus allowing the detection of as little as 0.1% of the Hg{sup 2+} spike transformed to labelled CH{sub 3}Hg{sup +}. The efficiency of the modified CH{sub 3}Hg{sup +} extraction procedure was assessed by radiolabelled CH{sub 3}Hg{sup +} spikes corresponding to concentrations of methylmercury between 0.05 and 4 ng L{sup -1}. The recoveries were 73.0{+-}6.0% and 77.5{+-}3.9% for marine and MilliQ water, respectively. The reduction potential was assessed by purging and trapping the radiolabelled elemental Hg in a permanganate solution. The method allows detection of the reduction of as little as 0.001% of labelled Hg{sup 2+} spiked to natural waters. To our knowledge, the optimised methodology is among the most sensitive available to study the Hg methylation and reduction potential, therefore allowing experiments to be done at spikes close to natural levels (1-10 ng L{sup -1}). - Highlights: Black-Right-Pointing-Pointer Inorganic mercury methylation and reduction in marine water were studied. Black-Right-Pointing-Pointer High specific activity {sup 197}Hg was used to label Hg{sup 2+} spikes at natural levels. Black-Right-Pointing-Pointer Methylmercury extraction had 73% efficiency for 0.05-4 ng L{sup -1} levels. Black-Right-Pointing-Pointer High sensibility to assess methylation potentials, below 0.1% of the spike. Black-Right-Pointing-Pointer High sensibility also for reduction potentials, as low as 0.001% of the spike.

  6. Distribution and air-sea exchange of mercury (Hg in the Yellow Sea

    Directory of Open Access Journals (Sweden)

    Z. J. Ci

    2011-01-01

    Full Text Available The Yellow Sea, surrounded by East China and the Korea Peninsula, is a potentially important receptor for anthropogenic mercury (Hg emissions from East Asia. However, there is little documentation about the distribution and cycle of Hg in this marine system. During the cruise covering the Yellow Sea in July 2010, gaseous elemental mercury (GEM or Hg(0 in the atmosphere, total Hg (THg, reactive Hg (RHg and dissolved gaseous mercury (DGM, largely Hg(0 in the waters were measured aboard the R/V Kexue III. The mean (±SD concentration of GEM over the entire cruise was 2.61±0.50 ng m−3 (range: 1.68 to 4.34 ng m−3, which were generally higher than other open oceans. The spatial distribution of GEM generally reflected a clear gradient with high levels near the coast of East China and low levels in open waters, suggesting the significant atmospheric Hg outflow from East China. The mean concentration of THg in the surface waters was 1.69±0.35 ng l−1 and the RHg accounted for a considerable fraction of THg (RHg: 1.08±0.28 ng l−1, %RHg/THg=63.9%. The mean concentration of DGM in the surface waters was 63.9±13.7 pg l−1 and always suggested the supersaturation of Hg(0 in the surface waters with respect to Hg(0 in the atmosphere (the degree of saturation: 7.83±2.29 with a range of 3.58–14.00. The mean Hg(0 flux at the air-sea interface was estimated to be 22.58±14.56 ng m−2 h−1 based on a two-layer exchange model. The high wind speed and DGM levels induced the extremely high Hg(0 emission rates. Measurements at three selected stations showed no clear vertical patterns of all three species of Hg in the water column. Overall, the elevated Hg levels in the Yellow Sea compared with other open oceans suggested that the human activity has significantly influenced the oceanic Hg cycle downwind of East Asia.

  7. Laser induced fluorescence (LIF) of Hg2 and Hg3 via dissociation of HgBr2 at 157 nm

    Science.gov (United States)

    Skordoulis, C.; Sarantopoulou, E.; Spyrou, S. M.; Kosmidis, C.; Cefalas, A. C.

    1991-06-01

    Laser induced fluorescence of the mercury clusters Hg2 and Hg3 in the spectral range between 300 nm to 510 nm has been obtained from the dissociation of HgBr2 at 7.88 eV (157.5 nm) with an F2 molecular laser, together with fluorescence from mercury atomic transitions from highly excited states. The excitation process involves two photon absorption which dissociates the molecule at 15.76 eV total photon energy with the subsequent formation of the metallic clusters.

  8. Laser induced fluorescence (LIF) of Hg2 and Hg3 via dissociation of HgBr2 at 157 nm

    International Nuclear Information System (INIS)

    Laser induced fluorescence of the mercury clusters Hg2 and Hg3 in the spectral range between 300 nm to 510 nm has been obtained from the dissociation of HgBr2 at 7.88 eV (157.5 nm) with an F2 molecular laser, together with fluorescence from mercury atomic transitions from highly excited states. The excitation process involves two photon absorption which dissociates the molecule at 15.76 eV total photon energy with the subsequent formation of the metallic clusters. (orig.)

  9. 40 CFR 60.4160 - Submission of Hg allowance transfers.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Submission of Hg allowance transfers... Times for Coal-Fired Electric Steam Generating Units Hg Allowance Transfers § 60.4160 Submission of Hg allowance transfers. An Hg authorized account representative seeking recordation of a Hg allowance...

  10. Magnetism, chemical spots, and stratification in the HgMn star phi Phoenicis

    CERN Document Server

    Makaganiuk, V; Piskunov, N; Jeffers, S V; Johns-Krull, C M; Keller, C U; Rodenhuis, M; Snik, F; Stempels, H C; Valenti, J A

    2011-01-01

    Mercury-manganese (HgMn) stars have been considered as non-magnetic and non-variable chemically peculiar (CP) stars for a long time. However, recent discoveries of the variability in spectral line profiles suggested an inhomogeneous surface distribution of chemical elements in some HgMn stars. From the studies of other CP stars it is known that magnetic field plays a key role in the formation of surface spots. All attempts to find magnetic fields in HgMn stars yielded negative results. In this study, we investigate a possible presence of the magnetic field in phi Phe (HD 11753) and reconstruct surface distribution of chemical elements that show variability in spectral lines. We also test a hypothesis that magnetic field is concentrated in chemical spots and look into the possibility that some chemical elements are stratified with depth in the stellar atmosphere.

  11. Identifying Key Proteins in Hg Methylation Pathways of Desulfovibrio by Global Proteomics, Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Summers, Anne O. [Univ. of Georgia, Athens, GA (United States). Dept. of Microbiology; Miller, Susan M. [Univ. of California, San Francisco, CA (United States). Dept. of Pharmaceutical Chemistry; Wall, Judy [Univ. of Missouri, Columbia, MO (United States). Dept. of Biochemistry; Lipton, Mary [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-06-18

    Elemental mercury, Hg(0) is a contaminant at many DOE sites, especially at Oak Ridge National Laboratory (ORNL) where the spread of spilled Hg and its effects on microbial populations have been monitored for decades. To explore the microbial interactions with Hg, we have devised a global proteomic approach capable of directly detecting Hg-adducts of proteins. This technique developed in the facultative anaerobe, Escherichia coli, allows us to identify the proteins most vulnerable to acute exposure to organomercurials phenyl- and ethyl-mercury (as surrogates for the highly neurotoxic methyl-Hg) (Polacco, et al, 2011). We have found >300 such proteins in all metabolic functional groups and cellular compartments; most are highly conserved and can serve as markers for acute Hg exposure (Zink, et al. 2016, in preparation). We have also discovered that acute Hg exposure severely disrupts thiol, iron and redox homeostases, and electrolyte balance (LaVoie, et al., 2015) Thus, we proposed to bring these techniques to bear on the central problem of identifying the cellular proteins involved in bacterial uptake and methylation of mercury and its release from the cell.

  12. HgCdTe APDs for free space optical communications

    Science.gov (United States)

    Rothman, J.; Lasfargues, G.; Abergel, J.

    2015-10-01

    HgCdTe avalanche photodiode single element detectors have been developed for a large scope of photon starved applications. The present communication is dedicated to use of these detectors for free space optical communications. In this perspective we present and discuss the sensitivity and bandwidth that has been measured directly on HgCdTe APDs and on detector modules. In particular, we report on the performance of TEC cooled large area detectors with sensitive diameters ranging from 30- 200 μm, characterised by detector gains of 2- 20 V/μW and noise equivalent input power of 0.1-1 nW for bandwidths ranging from 20 to 400 MHz. One of these detectors has been used during the lunar laser communication demonstration (LLCD) and the results The perspectives for high data rate transmission is estimated from the results of impulse response measurements on HgCdTe APDs. These results indicate that bandwidths close to 10 GHz can be achieved in these devices. The associated sensitivity at an APD gain of 100 is estimated to be below 4 photons rms (NEP<10 nW) for APDs operated at 300 K.

  13. Distribution and air-sea exchange of mercury (Hg in the Yellow Sea

    Directory of Open Access Journals (Sweden)

    Z. J. Ci

    2011-03-01

    Full Text Available The Yellow Sea, surrounded by East China and the Korea Peninsula, is a potentially important receptor for anthropogenic mercury (Hg emissions from East Asia. However, there is little documentation about the distribution and cycle of Hg in this marine system. During the cruise covering the Yellow Sea in July 2010, gaseous elemental mercury (GEM or Hg(0 in the atmosphere, total Hg (THg, reactive Hg (RHg and dissolved gaseous mercury (DGM, largely Hg(0 in the waters were measured aboard the R/V Kexue III. The mean (±SD concentration of GEM over the entire cruise was 2.61 ± 0.50 ng m−3 (range: 1.68 to 4.34 ng m−3, which were generally higher than other open oceans. The spatial distribution of GEM generally reflected a clear gradient with high levels near the coast of East China and low levels in open waters, suggesting the significant atmospheric Hg outflow from East China. The mean concentration of THg in the surface waters was 1.69 ± 0.35 ng l−1 and the RHg accounted for a considerable fraction of THg (RHg: 1.08 ± 0.28 ng l−1, %RHg/THg = 63.9%. The mean concentration of DGM in the surface waters was 63.9 ± 13.7 pg l−1 and always suggested the supersaturation of Hg(0 in the surface waters with respect to Hg(0 in the atmosphere (the degree of saturation: 7.8 ± 2.3 with a range of 3.6–14.0. The mean Hg(0 flux at the air-sea interface was estimated to be 18.3 ± 11.8 ng m−2 h−1 based on a two-layer exchange model. The high wind speed and DGM levels induced the extremely high Hg(0 emission rates. Measurements at three stations showed no clear vertical patterns of DGM, RHg and THg in the water column. Overall, the elevated Hg levels in the Yellow Sea compared with other open oceans suggested that the human activity has influenced the oceanic Hg cycle downwind of East Asia.

  14. High vortex mobility in Hg-1201

    International Nuclear Information System (INIS)

    We report on detailed investigations of the mixed state in the mercury based high-Tc superconductor HgBa2CuO4 (Hg-1201) by means of ac and dc magnetization measurements. Over large parts of the superconducting phase diagram the vortex mobility turned out to be remarkably high. From knowledge of the phase boundaries and the irreversibility line also determined, it became clear that in Hg-1201 thermal activation strongly supports the flux diffusion in both liquid and solid vortex phases. Thermally assisted flux diffusion widely stops here only for temperatures well below the melting line. In particular, the strong decrease of vortex mobility within the solid phase suggests a transition between different regimes originating from a different nature of vortex pinning, i.e. collective or single, and indicates a weak to strong pinning crossover of vortex matter in pure Hg-1201. A phenomenological description of the flux dynamics based on the classic diffusion formalism has been performed

  15. Siderophile and chalcophile metal variations in Tertiary picrites and basalts from West Greenland with implications for the sulphide saturation history of continental flood basalt magmas

    Science.gov (United States)

    Keays, Reid R.; Lightfoot, Peter C.

    2007-04-01

    Sixty-five million year old continental flood basalts crop out on Qeqertarssuaq Island and the Nuussuaq Peninsula in West Greenland, and they include ˜1,000 m of picritic lavas and discrete 10- to 50-m-thick members of highly contaminated basalts. On Qeqertarssuaq, the lavas are allocated to the Vaîgat and Maligât Formations of which the former includes the Naujánguit member, which consists of picrites with 7-29 wt% MgO, 80-1,400 ppm Ni, 5.7-9.4 ppb Pt and 4.2-12.9 ppb Pd. The Naujánguit member contains two horizons of contaminated basalts, the Asûk and Kûgánguaq, which have elevated SiO2 (52-58 wt%) and low to moderate MgO (7.5-12.8 wt%). These lavas are broadly characterized by low Cu and Ni abundances (average, 40 ppm Ni and 45 ppm Cu) and very low Pt (0.16-0.63 ppb) and Pd (0.13-0.68 ppb) abundances, and in the case of the Asûk, they contain shale xenoliths and droplets of native iron and troilite. The contaminated basalts from Nuussuaq, the B0 to B4 members, are also usually Ni-, Cu-, and platinum-group elements (PGE)-depleted. The geochemical signatures (especially the ratios of incompatible trace elements such as Th/Nb) of all of the contaminated basalts from Qeqertarssuaq and some of those from Nuussuaq record what appears to be a chemical contribution from deltaic shales that lie immediately below the lavas. This suggests that the contamination of the magmas occurred during the migration of the magmas through plumbing systems developed in sedimentary rocks, and hence, at a high crustal level. Nickel, Cu, and PGE depletion together with geochemical signatures produced by crustal contamination are also a feature of Siberian Trap basalts from the Noril’sk region. These basalts belong to the 0- to 500-m thick, ˜5,000- to 10,000-km3 Nadezhdinsky Formation, which is centered in the Noril’sk Region. A major difference between Siberia and West Greenland is that PGE depletion in the Nadezhdinsky Formation samples with the lowest Cu and Ni contents is

  16. HgTe-CdTe SUPERLATTICES

    OpenAIRE

    Smith, D.; Mcgill, T.

    1984-01-01

    We report on a theoretical study of the electronic properties of HgTe-CdTe superlattices. The band gap as a function of layer thickness, effective masses normal to the layer plane and tunneling length are compared to the corresponding (Hg, Cd)Te alloys. We find that the superlattice possesses a number of properties that may make it superior to the corresponding alloy as an infrared material.

  17. HgTe based topological insulators

    International Nuclear Information System (INIS)

    This PhD thesis summarizes the discovery of topological insulators and highlights the developments on their experimental observations. The work focuses on HgTe. The thesis is structured as follows: - The first chapter of this thesis will give a brief overview on discoveries in the field of topological insulators. It focuses on works relevant to experimental results presented in the following chapters. This includes a short outline of the early predictions and a summary of important results concerning 2-dimensional topological insulators while the final section discusses observations concerning 3-dimensional topological insulators. - The discovery of the quantum spin Hall effect in HgTe marked the first experimental observation of a topological insulator. Chapter 2 focuses on HgTe quantum wells and the quantum spin Hall effect. The growth of high quality HgTe quantum wells was one of the major goals for this work. In a final set of experiments the spin polarization of the edge channels was investigated. Here, we could make use of the advantage that HgTe quantum well structures exhibit a large Rashba spin orbit splitting. - HgTe as a 3-dimensional topological insulator is presented in chapter 3. - Chapters 4-6 serve as in depth overviews of selected works: Chapter 4 presents a detailed overview on the all electrical detection of the spin Hall effect in HgTe quantum wells. The detection of the spin polarization of the quantum spin Hall effect is shown in chapter 5 and chapter 6 gives a detailed overview on the quantum Hall effect originating from the topological surface state in strained bulk HgTe.

  18. Isotopic Hg in an Allende carbon-rich residue

    Science.gov (United States)

    Reed, G. W., Jr.; Jovanovic, S.

    1990-01-01

    A carbon-rich residue from Allende subjected to stepwise heating yielded two isotopically resolvable types of Hg: one with an (Hg-196)/(Hg-202) concentration ratio the same as terrestrial (monitor) Hg; the other enriched in Hg-196 relative to Hg-202 by about 60 percent. Hg with the 202 isotope enriched relative to 196, as is found in bulk Allende, was not observed. Whether the result of mass fractionation or nucleosynthesis, the distinct types of Hg entered different carrier phases and were not thermally mobilized since the accretion of the Allende parent body.

  19. Single crystal growth, electronic structure and optical properties of Cs2HgBr4

    Science.gov (United States)

    Lavrentyev, A. A.; Gabrelian, B. V.; Vu, V. T.; Shkumat, P. N.; Parasyuk, O. V.; Fedorchuk, A. O.; Khyzhun, O. Y.

    2015-10-01

    We report on successful synthesis of high-quality single crystal of cesium mercury tetrabromide, Cs2HgBr4, by using the vertical Bridgman-Stockbarger method as well as on studies of its electronic structure. For the Cs2HgBr4 crystal, we have recorded X-ray photoelectron spectra for both pristine and Ar+ ion-bombarded surfaces. Our data indicate that the Cs2HgBr4 single crystal surface is rather sensitive with respect to Ar+ ion-bombardment. In particular, such a treatment of the Cs2HgBr4 single crystal surface alters its elemental stoichiometry. To explore peculiarities of the energy distribution of total and partial densities of states within the valence band and the conduction band of Cs2HgBr4, we have made band-structure calculations based on density functional theory (DFT) employing the augmented plane wave+local orbitals (APW+lo) method as incorporated in the WIEN2k package. The APW+lo calculations allow for concluding that the Br 4p states make the major contributions in the upper portion of the valence band, while its lower portion is dominated by contributors of the Hg 5d and Cs 5p states. Further, the main contributors to the bottom of the conduction band of Cs2HgBr4 are the unoccupied Br p and Hg s states. In addition, main optical characteristics of Cs2HgBr4 such as dispersion of the absorption coefficient, real and imaginary parts of dielectric function, electron energy-loss spectrum, refractive index, extinction coefficient and optical reflectivity have been explored from the first-principles band-structure calculations.

  20. An experimental study of formation of the mercury mixed halides HgClBr and HgBrI and of their purity

    OpenAIRE

    Rabia Ahmad; Jamshed Ali; Qamer Faisal

    2015-01-01

    Claims to have produced the mixed halides of mercury are very old. However, their stability or even their very existence was seriously questioned by Ammlung and Brill several decades back, on the basis of their study, in several solvents, of what was thought to be HgBrI. The mixed halide HgClI was already known to be unstable. On the basis of these facts, which were also lent some theoretical support, it was strongly conjectured that the mixed halides of mercury and similar elements, were...

  1. Experimental study on Hg0 removal from flue gas over columnar MnOx-CeO2/activated coke

    International Nuclear Information System (INIS)

    Highlights: • The Hg0 removal efficiency over columnar MnCe6/activated coke up to 94%. • MnOx and CeO2 exhibited a significant synergistic role in Hg0 removal over MnCe/AC. • Lattice oxygen, chemisorbed oxygen and OH groups on the surface of MnCe/AC contributed to Hg0 oxidation. • Hg0 removal mechanisms over MnCe/AC were identified firstly. - Abstract: Mn-Ce mixed oxides supported on commercial columnar activated coke (MnCe/AC) were employed to remove elemental mercury (Hg0) at low temperatures (100–250 °C) without the assistance of HCl in flue gas. The samples were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), X-ray photoelectron spectroscopy (XPS) and temperature programmed desorption (TPD). Effects of some factors, including Mn-Ce loading values, active component, reaction temperatures and flue gas components (O2, SO2, NO, H2O), on Hg0 removal efficiency were investigated. Results indicated that the optimal Mn-Ce loading value and reaction temperature were 6% and 190 °C, respectively. Considerable high Hg0 removal efficiency (>90%) can be obtained over MnCe6/AC under both N2/O2 atmosphere and simulated flue gas atmosphere at 190 °C. Besides, it was observed that O2 and NO exerted a promotional effect on Hg0 removal, H2O exhibited a suppressive effect, and SO2 hindered Hg0 removal seriously when in the absence of O2. Furthermore, the XPS spectra of Hg 4f and Hg-TPD results showed that the captured mercury were existed as Hg0 and HgO on the MnCe6/AC, and HgO was the major species, which illustrated that adsorption and catalytic oxidation process were included for Hg0 removal over MnCe6/AC, and catalytic oxidation played the critical role. What's more, both lattice oxygen and chemisorbed oxygen or OH groups on MnCe6/AC contributed to Hg0 oxidation. MnCe6/AC, which exhibited excellent performance on Hg0 removal in the absence of HCl, appeared to be promising in industrial application, especially for low-rank coal fired

  2. Accumulation rates and predominant atmospheric sources of natural and anthropogenic Hg and Pb on the Faroe Islands

    Energy Technology Data Exchange (ETDEWEB)

    Shotyk, W.; Goodsite, M.E.; Roos-Barraclough, F.; Givelet, N.; Le Roux, G.; Weiss, D.; Cheburkin, A.K.; Knudsen, K.; Heinemeier, J.; Van der Knaap, W.O.; Norton, S.A.; Lohse, C. [University of Heidelberg, Heidelberg (Germany)

    2005-01-01

    A monolith representing 5420 C-14 yr of peat accumulation was collected from a blanket bog at Myrarnar, Faroe Islands. The maximum Hg concentration (498 ng/g at a depth of 4.5 cm) coincides with the maximum concentration of anthropogenic Pb (111 {mu}g/g). Age dating of recent peat accumulation using Pb-210 (CRS model) shows that the maxima in Hg and Pb concentrations occur at AD 1954 {+-} 2. These results, combined with the isotopic composition of Pb in that sample (Pb-206/Pb-207 = 1.1720 {+-} 0.0017), suggest that coal burning was the dominant source of both elements. From the onset of peat accumulation (ca. 4286 BC) until AD 1385, the ratios Hg/Br and Hg/Se were constant (2.2 {+-} 0.5 x 10{sup -4} and 8.5 {+-} 1.8 x 10{sup -3}, respectively). Since then, Hg/Br and Hg/Se values have increased, also reaching their maxima in AD 1954. The age date of the maximum concentrations of anthropogenic Hg and Pb in the Faroe Islands is consistent with a previous study of peat cores from Greenland and Denmark which showed maximum concentrations in AD 1953. The average rate of atmospheric Hg accumulation from 1520 BC to AD 1385 was 1.27 {+-} 0.38 {mu}g/m{sup 2}/yr. Episodic volcanic emissions and the continual supply of marine aerosols to the Faroe Islands were found not to have contributed significantly to the Hg inventory or the Hg accumulation rates, relative to these other areas. The maximum rate of Hg accumulation was 34 {mu}g/m{sup 2}/yr. The greatest fluxes of anthropogenic Hg accumulation calculated using Br and Se, respectively, were 26 and 31 {mu}g/m{sup 2}/yr.

  3. Synthesis and Crystal Structure of New Coordination Compound Mn2Hg4(SCN)12%新型配合物Mn2Hg4(SCN)12的合成与晶体结构分析

    Institute of Scientific and Technical Information of China (English)

    李广慧; 方奇; 薛刚; 于文涛

    2005-01-01

    A new inorganic coordination compound Mn2Hg4(SCN)12 was synthesized. The grown crystals were characterized by elemental analysis, infrared spectroscopic analysis and powder crystal X-ray diffraction in detail. The crystal structure of Mn2Hg4(SCN)12 was determined by single-crystal X-ray diffraction. It belongs to monoclinic system, P21/c space group. The cell dimensions are: a=1.171 6 nm, b=1.431 05 nm, c=2.105 1 nm,β=100.738°,and Z=4. In the structure of it, half of Mn2+ cations have five-coordinate number, and other half of Mn2+ cations have six-coordinate number; 3/4 of Hg2+ cations are coordinated by four SCN-, 1/4 of Hg2+ cations are coordinated by three SCN- and one NCS-, all the coordination geometry of Hg2+ show slightly distorted tetrahedrons. CCDC:244939.

  4. Emission spectrographic determination of volatile trace elements in geologic materials by a carrier distillation technique

    Science.gov (United States)

    Barton, H.N.

    1986-01-01

    Trace levels of chalcophile elements that form volatile sulfide minerals are determined in stream sediments and in the nonmagnetic fraction of a heavy-mineral concentrate of stream sediments by a carrier distillation emission spectrographic method. Photographically recorded spectra of samples are visually compared with those of synthetic standards for the two sample types. Rock and soil samples may also be analyzed by comparison with the stream-sediment standards. A gallium oxide spectrochemical carrier/buffer enhances the early emission of the volatile elements. Detection limits in parts per million attained are: Sb 5, As 20, Bi 0.1, Cd 1, Cu 1, Pb 2, Ag 0.1, Zn 2, and Sn 0.1. A comparison with other methods of analysis, total-burn emission and atomic absorption spectroscopy, shows good correlation for standard reference for materials and samples from a variety of geologic terranes. ?? 1986.

  5. Volatility in the lunar crust: Trace element analyses of lunar minerals by PIXE proton microprobe

    Science.gov (United States)

    Norman, M. D.; Griffin, W. L.; Ryan, C. G.

    1993-01-01

    In situ determination of mineral compositions using microbeam techniques can characterize magma compositions through mineral-melt partitioning, and be used to investigate fine-grained or rare phases which cannot be extracted for analysis. Abundances of Fe, Mn, Sr, Ga, Zr, Y, Nb, Zn, Cu, Ni, Se, and Sb were determined for various mineral phases in a small number of lunar highlands rocks using the PIXE proton microprobe. Sr/Ga ratios of plagioclase and Mn/Zn ratios of mafic silicates show that the ferroan anorthosites and Mg-suite cumulates are depleted in volatile lithophile elements to about the same degree compared with chondrites and the Earth. This links the entire lunar crust to common processes or source compositions. In contrast, secondary sulfides in Descartes breccia clasts are enriched in chalcophile elements such as Cu, Zn, Ni, Se, and Sb, and represent a potential resource in the lunar highlands.

  6. HgCdTe barrier infrared detectors

    Science.gov (United States)

    Kopytko, M.; Rogalski, A.

    2016-05-01

    In the last decade, new strategies to achieve high-operating temperature (HOT) detectors have been proposed, including barrier structures such as nBn devices, unipolar barrier photodiodes, and multistage (cascade) infrared detectors. The ability to tune the positions of the conduction and valence band edges independently in a broken-gap type-II superlattices is especially helpful in the design of unipolar barriers. This idea has been also implemented in HgCdTe ternary material system. However, the implementation of this detector structure in HgCdTe material system is not straightforward due to the existence of a valence band discontinuity (barrier) at the absorber-barrier interface. In this paper we present status of HgCdTe barrier detectors with emphasis on technological progress in fabrication of MOCVD-grown HgCdTe barrier detectors achieved recently at the Institute of Applied Physics, Military University of Technology. Their performance is comparable with state-of-the-art of HgCdTe photodiodes. From the perspective of device fabrication their important technological advantage results from less stringent surface passivation requirements and tolerance to threading dislocations.

  7. 40 CFR 60.45Da - Standard for mercury (Hg).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standard for mercury (Hg). 60.45Da... for mercury (Hg). (a) For each coal-fired electric utility steam generating unit other than an IGCC... gases that contain mercury (Hg) emissions in excess of each Hg emissions limit in paragraphs...

  8. 40 CFR 60.4153 - Recordation of Hg allowance allocations.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Recordation of Hg allowance allocations... Times for Coal-Fired Electric Steam Generating Units Hg Allowance Tracking System § 60.4153 Recordation of Hg allowance allocations. (a) By December 1, 2006, the Administrator will record in the Hg...

  9. 40 CFR 60.4111 - Alternate Hg designated representative.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Alternate Hg designated representative... Times for Coal-Fired Electric Steam Generating Units Hg Designated Representative for Hg Budget Sources § 60.4111 Alternate Hg designated representative. (a) A certificate of representation under §...

  10. 40 CFR 60.4114 - Objections concerning Hg designated representative.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Objections concerning Hg designated... Times for Coal-Fired Electric Steam Generating Units Hg Designated Representative for Hg Budget Sources § 60.4114 Objections concerning Hg designated representative. (a) Once a complete certificate...

  11. Accumulation rates and predominant atmospheric sources of natural and anthropogenic Hg and Pb on the Faroe Islands

    Science.gov (United States)

    Shotyk, W.; Goodsite, M. E.; Roos-Barraclough, F.; Givelet, N.; Le Roux, G.; Weiss, D.; Cheburkin, A. K.; Knudsen, K.; Heinemeier, J.; van Der Knaap, W. O.; Norton, S. A.; Lohse, C.

    2005-01-01

    A monolith representing 5420 14C yr of peat accumulation was collected from a blanket bog at Myrarnar, Faroe Islands. The maximum Hg concentration (498 ng/g at a depth of 4.5 cm) coincides with the maximum concentration of anthropogenic Pb (111 μg/g). Age dating of recent peat accumulation using 210Pb (CRS model) shows that the maxima in Hg and Pb concentrations occur at AD 1954 ± 2. These results, combined with the isotopic composition of Pb in that sample ( 206Pb/ 207Pb = 1.1720 ± 0.0017), suggest that coal burning was the dominant source of both elements. From the onset of peat accumulation (ca. 4286 BC) until AD 1385, the ratios Hg/Br and Hg/Se were constant (2.2 ± 0.5 × 10 -4 and 8.5 ± 1.8 × 10 -3, respectively). Since then, Hg/Br and Hg/Se values have increased, also reaching their maxima in AD 1954. The age date of the maximum concentrations of anthropogenic Hg and Pb in the Faroe Islands is consistent with a previous study of peat cores from Greenland and Denmark (dated using the atmospheric bomb pulse curve of 14C), which showed maximum concentrations in AD 1953. The average rate of atmospheric Hg accumulation from 1520 BC to AD 1385 was 1.27 ± 0.38 μg/m 2/yr. The Br and Se concentrations and the background Hg/Br and Hg/Se ratios were used to calculate the average rate of natural Hg accumulation for the same period, 1.32 ± 0.36 μg/m 2/yr and 1.34 ± 0.29 μg/m 2/yr, respectively. These fluxes are similar to the preanthropogenic rates obtained using peat cores from Switzerland, southern Greenland, southern Ontario, Canada, and the northeastern United States. Episodic volcanic emissions and the continual supply of marine aerosols to the Faroe Islands, therefore, have not contributed significantly to the Hg inventory or the Hg accumulation rates, relative to these other areas. The maximum rate of Hg accumulation was 34 μg/m 2/yr. The greatest fluxes of anthropogenic Hg accumulation calculated using Br and Se, respectively, were 26 and 31 μg/m 2

  12. Distribution of Heavy Metal Content Hg and Cr of Environmental Samples at Surabaya Area

    International Nuclear Information System (INIS)

    Determination of Hg and Cr content of Surabaya river and coastal environmental samples using Instrumental Neutron Activation Analysis (INAA) have been done. The environmental samples were water, sediment, Eichhornia crassipes (Mart) Solmms, Rhizophora stylosa, Johnius (Johnieops) borneensis fish, and Moolgarda delicate fish at 12 locations selected of Surabaya area. Dry powder of sediment and biotic samples and concentrate water samples was irradiated by neutron flux 1.05 x 1011n.cm-2.det-1 during 12 hours. The analytical result showed that the concentration of the heavy metals of river water are smaller than Perda Surabaya City No. 02/2004 for the 4th level water which are Hg (0.005 ppm) and Cr (1.000 ppm). All locations coastal water samples have Hg and Cr concentrations are higher than Kepmen LH No.51/2004 Hg (0.001 ppm) and Cr (0.005 ppm). The Hg concentration of fish samples have exceeded the threshold according to Kep. Dirjen POM No.03725/B/SK/VII/89 about the maximum concentration of metal pollution in food. The concentration of heavy metals in sediment, Eichhornia crassipes (Mart) Solmms and Rhizophora stylosa are not regulated, so then heavy metals pollution can not be referred to. The concentration of Hg and Cr elements of water samples are smaller than that of biotic and sediment samples. The distribution factor (Fd) is bigger than bioaccumulation factor (Fb). (author)

  13. Real-time dark-field scattering microscopic monitoring of the in situ growth of single Ag@Hg nanoalloys.

    Science.gov (United States)

    Liu, Yue; Huang, Cheng Zhi

    2013-12-23

    A comprehensive understanding of the growth mechanism of nanoalloys is beneficial in designing and synthesizing nanoalloys with precisely tailored properties to extend their applications. Herein, we present the investigation in this aspect by real-time monitoring of the in situ growth of single Ag@Hg nanoalloys, through direct amalgamation of Ag nanoparticles with elemental mercury, by dark-field scattering microscopy. Four typically shaped Ag nanoparticles, such as rods, triangular bipyramids, cubes, and spheres, were used as seeds for studying the growth of Ag@Hg nanoalloys. The scattered light of Ag nanoparticles of different shapes, on exposure to the growth solution, exhibited a noticeable blue-shift followed by a red-shift, suggesting the growth of Ag@Hg nanoalloys. The formation of Ag@Hg nanoalloys was confirmed by scanning electron microscopy, high-resolution transmit electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, and elemental mapping and line scanning. Further analysis of the time-dependent spectral data and morphological change of single nanoparticles during the growth led to the visual identification of the growth mechanism of single Ag@Hg nanoalloys. Three important steps were involved: first, rapid adsorption of Hg atoms onto Ag nanoparticles; second, initial diffusion of Hg atoms into Ag nanoparticles, rounding or shortening the particles; third, further diffusion of Hg atoms leading to the formation of spherical Ag@Hg nanoalloys. On the basis of these results, Ag@Hg nanoalloys with given optical properties can be synthesized. Moreover, dark-field scattering microscopy is expected to be a powerful tool used for real-time monitoring of the in situ growth of other metal nanoparticles. PMID:24279755

  14. History of HgCdTe infrared detectors at BAE Systems

    Science.gov (United States)

    Reine, Marion B.

    2009-05-01

    This paper describes the history and current status of HgCdTe infrared detector technology at BAE Systems in Lexington, Massachusetts, whose corporate legacy includes Honeywell (1962-1991), Loral (1991-1996), and Lockheed Martin (1996-2000). The Honeywell Radiation Center was founded in 1962 in Boston, Massachusetts. Shortly thereafter, primitive HgCdTe samples began to arrive from the Honeywell Corporate Research Center in Hopkins, Minnesota for evaluation as possible IR detectors. In 1967, procedures for the growth of HgCdTe inhomogeneous large-grain-polycrystalline ingots by a modified Bridgman method were transferred from the Research Center to the Radiation Center. In 1968 the Radiation Center moved to new facilities in Lexington, Massachusetts. HgCdTe activities have expanded and evolved in the ensuing years, remaining in the Lexington, Massachusetts facilities up to the present. This paper reviews the role that the Honeywell/Loral/Lockheed Martin/BAE Systems facility in Lexington, Massachusetts has played in the success of HgCdTe as today's preeminent, highest performance, most versatile, and most widely applicable infrared detector material for the 1-30 μm spectral range. We examine the evolution of both photoconductive and photovoltaic HgCdTe detectors from early unpassivated ill-understood single-element devices through production of linear arrays and to today's large-format two-dimensional IR Focal Plane Arrays for the most demanding spaceborne applications. We examine the progress made in HgCdTe materials science and technology, including improved highly-homogeneous bulk crystal growth, liquid phase epitaxy and metalorganic vapor phase epitaxy. Various devices are used to illustrate the evolution of HgCdTe technology, including the n-type photoconductor, the trapping-mode photoconductor, and the two-layer LPE P-on-n heterojunction.

  15. Speciation, Characterization and Mobility of As, Se and Hg in Flue Gas Desulphurization Residues

    Energy Technology Data Exchange (ETDEWEB)

    Al-Abed, S.R.; Jegadeesan, G.; Scheckel, K.G.; Tolaymat, T. (EPA); (Pegasus)

    2008-06-23

    Flue gas from coal combustion contains significant amounts of volatile toxic trace elements such as arsenic (As), selenium (Se), and mercury (Hg). The capture of these elements in the flue gas desulphurization (FGD) scrubber unit has resulted in generation of a metal-laden residue. With increasing reuse of the FGD residues in beneficial applications, it is important to determine metal speciation and mobility to understand the environmental impact of its reuse. In this paper, we report the solid phase speciation of As, Se, and Hg in FGD residues using X-ray absorption spectroscopy (XAS), X-ray fluorescence spectroscopy (XRF), and sequential chemical extraction (SCE) techniques. The SCE results combined with XRF data indicated a strong possibility of As association with iron oxides, whereas Se was distributed among all geochemical phases. Hg appeared to be mainly distributed in the strong-complexed phase. XRF images also suggested a strong association of Hg with Fe oxide materials within FGD residues. XAS analysis indicated that As existed in its oxidized state (As(V)), whereas Se and Hg was observed in primarily reduced states as selenite (Se(IV)) and Hg(I), respectively. The results from the SCE and variable pH leaching tests indicated that the labile fractions of As, Se, and Hg were fairly low and thus suggestive of their stability in the FGD residues. However, the presence of a fine fraction enriched in metal content in the FGD residue suggested that size fractionation is important in assessing the environmental risks associated with their reuse.

  16. Speciation, characterization, and mobility of As, Se, and Hg in flue gas desulphurization residues

    Energy Technology Data Exchange (ETDEWEB)

    Souhail R. Al-Abed; Gautham Jegadeesan; Kirk G. Scheckel; Thabet Tolaymat [United States Environmental Protection Agency, Cincinnati, OH (United States). National Risk Management Research Laboratory

    2008-03-01

    Flue gas from coal combustion contains significant amounts of volatile toxic trace elements such as arsenic (As), selenium (Se), and mercury (Hg). The capture of these elements in the flue gas desulphurization (FGD) scrubber unit has resulted in generation of a metal-laden residue. With increasing reuse of the FGD residues in beneficial applications, it is important to determine metal speciation and mobility to understand the environmental impact of its reuse. In this paper, we report the solid phase speciation of As, Se, and Hg in FGD residues using X-ray absorption spectroscopy (XAS), X-ray fluorescence spectroscopy (XRF), and sequential chemical extraction (SCE) techniques. The SCE results combined with XRF data indicated a strong possibility of As association with iron oxides, whereas Se was distributed among all geochemical phases. Hg appeared to be mainly distributed in the strong-complexed phase. XRF images also suggested a strong association of Hg with Fe oxide materials within FGD residues. XAS analysis indicated that As existed in its oxidized state (As(V)), whereas Se and Hg was observed in primarily reduced states as selenite (Se(IV)) and Hg(I), respectively. The results from the SCE and variable pH leaching tests indicated that the labile fractions of As, Se, and Hg were fairly low and thus suggestive of their stability in the FGD residues. However, the presence of a fine fraction enriched in metal content in the FGD residue suggested that size fractionation is important in assessing the environmental risks associated with their reuse. 34 refs., 3 figs., 4 tabs.

  17. Synthesis of HgBa2Ca3Cu4O10+δ(Hg-1234) and HgBa2Ca4Cu5O12+δ(Hg-1245) from oxygen controlled precursors under high pressure

    International Nuclear Information System (INIS)

    Effects of oxygen content in the precursor have been investigated on the synthesis of HgBa2Ca4Cu5O12+δ(Hg-1245) under high pressure. The superconducting phases continuously changed from Hg-1234 to Hg-1245 with reducing the oxygen content in the precursor of Ba2Ca4Cu5O11+δ. Samples of Hg- 1245 have been synthesized by optimizing the oxygen content of the precursor with the stoichiometric composition. (author)

  18. 46 CFR 53.05-1 - Safety valve requirements for steam boilers (modifies HG-400 and HG-401).

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Safety valve requirements for steam boilers (modifies HG-400 and HG-401). 53.05-1 Section 53.05-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... requirements for steam boilers (modifies HG-400 and HG-401). (a) The pressure relief valve requirements and...

  19. Spatial-temporal dynamics and sources of total Hg in a hydroelectric reservoir in the Western Amazon, Brazil.

    Science.gov (United States)

    Pestana, I A; Bastos, W R; Almeida, M G; de Carvalho, D P; Rezende, C E; Souza, C M M

    2016-05-01

    Damming rivers to construct hydroelectric reservoirs results in a series of impacts on the biogeochemical Hg cycle. For example, modifying the hydrodynamics of a natural watercourse can result in the suspension and transport of Hg deposits in the water column, which represents an exposure risk for biota. The objective of this study was to evaluate the influences of seasonality on the dispersion of total Hg in the Hydroelectric Power Plant (HPP)-Samuel Reservoir (Porto Velho/Brazil). Sampling campaigns were performed during the three following hydrological periods characteristic of the region: low (Oct/2011), ebbing (May/2012), and high (Feb/2013) water. Sediment profiles, suspended particulate matter (SPM), and aquatic macrophytes (Eicchornia crassipes and Oryza spp.) were collected, and their Hg concentrations and isotopic and elemental C and N signatures were determined. The drainage basin significantly influenced the SPM compositions during all the periods, with a small autochthonous influence from the reservoir during the low water. The highest SPM Hg concentrations inside the reservoir were observed during the high water period, suggesting that the hydrodynamics of this environment favor the suspension of fine SPM, which has a higher Hg adsorption capacity. The Hg concentrations in the sediment profiles were ten times lower than those in the SPM, indicating that large particles with low Hg concentrations were deposited to form the bottom sediment. Hg concentrations were higher in aquatic macrophyte roots than in their leaves and appeared to contribute to the formation of SPM during the low water period. In this environment, Hg transport mainly occurs in SPM from the Jamari River drainage basin, which is the primary source of Hg in this environment. PMID:26846239

  20. Quasiparticle excitations in superdeformed {sup 192}Hg

    Energy Technology Data Exchange (ETDEWEB)

    Lauritsen, T.; Carpenter, M.P.; Janssens, R.V.F. [and others

    1995-08-01

    The nucleus {sup 192}Hg plays a pivotal role for superdeformation in the mass 190 region, since calculations of single-particle levels show large shell-gaps for the superdeformed (SD) shape at N = 112 and Z = 80. As a result, {sup 192}Hg is referred to as the doubly magic SD nucleus for the A = 190 region. In previous studies, only one superdeformed band was observed in this nucleus, and this fact was cited as indirect evidence that large shell gaps do indeed exist at the proposed particle numbers.

  1. Quasiparticle excitations in superdeformed 192Hg

    International Nuclear Information System (INIS)

    For the first time, two excited superdeformed (SD) bands have been observed in the double closed shell superdeformed nucleus 192Hg. One of the SD bands exhibits a pronounced peak in the dynamic moment of inertia which is interpreted as a crossing between two excited SD configurations involving the N=7 intruder and the [512]5/2 orbitals. This is only the second occurrence of such a crossing in a SD nucleus around A=190. The second excited SD band has near identical transition energies to an excited SD band in 191Hg

  2. Electric field gradients in Hg compounds

    DEFF Research Database (Denmark)

    Arcisauskaité, Vaida; Knecht, Stefan; Sauer, Stephan P. A.;

    2012-01-01

    We examine the performance of Density Functional Theory (DFT) approaches based on the Zeroth-Order Regular Approximation (ZORA) Hamiltonian (with and without inclusion of spinorbit coupling) for predictions of electric ¿eld gradients (EFGs) at the heavy atom Hg nucleus. This is achieved by compar......We examine the performance of Density Functional Theory (DFT) approaches based on the Zeroth-Order Regular Approximation (ZORA) Hamiltonian (with and without inclusion of spinorbit coupling) for predictions of electric ¿eld gradients (EFGs) at the heavy atom Hg nucleus. This is achieved...

  3. An experimental study of formation of the mercury mixed halides HgClBr and HgBrI and of their purity

    Directory of Open Access Journals (Sweden)

    Rabia Ahmad

    2015-06-01

    Full Text Available Claims to have produced the mixed halides of mercury are very old. However, their stability or even their very existence was seriously questioned by Ammlung and Brill several decades back, on the basis of their study, in several solvents, of what was thought to be HgBrI. The mixed halide HgClI was already known to be unstable. On the basis of these facts, which were also lent some theoretical support, it was strongly conjectured that the mixed halides of mercury and similar elements, were expected to be unstable. However, the matter does not seem to have received the attention it deserved. It was in this light that this study was taken up. What has been thought to be HgClBr has been produced by several methods and HgBrI by one or rather two methods. The product has been subjected to X-ray diffraction, FTIR and Raman studies. Studies confined to the solid product are being reported here and only those results are being presented for which all the three techniques could be employed. These studies show that a new product is indeed formed in most of these cases, but the product is not pure in any of these cases, although the impurity seems to be quite small in most of these cases. This calls for having a thorough look at not only the mixed halides of the elements, but of all compounds claimed to be like:

  4. Heterogeneous Reduction Pathways for Hg(II) Species on Dry Aerosols: A First-Principles Computational Study.

    Science.gov (United States)

    Tacey, Sean A; Xu, Lang; Mavrikakis, Manos; Schauer, James J

    2016-04-01

    The atmospheric lifetime of mercury is greatly impacted by redox chemistry resulting from the high deposition rate of reactive mercury (Hg(II)) compared to elemental mercury (Hg(0)). Recent laboratory and field studies have observed the reduction of Hg(II), but the chemical mechanism for this reaction has not been identified. Recent experimental work has shown that the reduction reaction is heterogeneous and can occur on iron and sodium chloride aerosol surfaces. This study explores the use of density functional theory calculations to discern the reduction pathways of HgCl2, HgBr2, Hg(NO3)2, and HgSO4 on clean Fe(110), NaCl(100), and NaCl(111)(Na) surfaces. Potential energy surfaces were prepared for the various reduction pathways, indicating that the reduction pathway leading to the production of gas-phase elemental mercury is highly favorable on Fe(110) and NaCl(111)(Na). Moreover, the Fe(110) surface requires an external energy source of ∼0.5 eV to desorb the reduced mercury, whereas the NaCl(111)(Na) surface requires no energy input. The results indicate that a number of mercury species can be reduced on metallic iron and sodium chloride surfaces, which are known aerosol components, and that a photochemical reaction involving the aerosol surface is likely needed for the reaction to be catalytic. PMID:27014805

  5. Possible link between Hg and Cd accumulation in the brain of long-finned pilot whales (Globicephala melas).

    Science.gov (United States)

    Gajdosechova, Zuzana; Brownlow, Andrew; Cottin, Nicolas T; Fernandes, Mariana; Read, Fiona L; Urgast, Dagmar S; Raab, Andrea; Feldmann, Jörg; Krupp, Eva M

    2016-03-01

    The bioaccumulation of metals was investigated by analysis of liver, kidney, muscle and brain tissue of a pod of 21 long-finned pilot whales (Globicephala melas) of all ages stranded in Scotland, UK. The results are the first to report cadmium (Cd) passage through the blood-brain barrier of pilot whales and provide a comprehensive study of the long-term (up to 35 years) mammalian exposure to the environmental pollutants. Additionally, linear accumulation of mercury (Hg) was observed in all studied tissues, whereas for Cd this was only observed in the liver. Total Hg concentration above the upper neurochemical threshold was found in the sub-adult and adult brains and methylmercury (MeHg) of 2.2mg/kg was found in the brain of one individual. Inter-elemental analysis showed significant positive correlations of Hg with selenium (Se) and Cd with Se in all studied tissues. Furthermore, differences in the elemental concentrations in the liver and brain tissues were found between juvenile, sub-adult and adult groups. The highest concentrations of manganese, iron, zinc, Se, Hg and MeHg were noted in the livers, whereas Cd predominantly accumulated in the kidneys. High concentrations of Hg and Cd in the tissues of pilot whales presented in this study reflect ever increasing toxic stress on marine mammals. PMID:26748005

  6. Isotope tracing of Hg pollution from artisanal small scale gold mining in an aquatic ecosystem of Amapá, Brazil

    Science.gov (United States)

    Adler Miserendino, R.; Silbergeld, E. K.; Guimarães, J. D.; Ghosh, S.; Bergquist, B. A.

    2010-12-01

    Artisinal small scale gold mining (ASGM) is a central economic activity throughout the developing world. It is both a poverty driven and poverty alleviating process; however, ASGM leads to extensive pollution of waterways through the use of Hg to extract gold from deposits. There have been many studies conducted in the Amazon showing elevated levels of Hg in fish and sediment downstream of ASGM sites; however, the debate continues about the contribution of Hg from ASGM versus other potential sources of Hg. In this study, we investigate whether Hg stable isotope analysis can be used to trace mercury pollution from an ASGM site through an aquatic ecosystem in Amapá, Brazil. We measured the Hg isotopic composition of sediment cores from two lakes, only one of which was heavily impacted by the use of elemental Hg in ASGM, as well as from grab samples at the AGSM site and upstream and downstream from the AGSM site along the river which connects the polluted lake to the ASGM site. Hg from all samples were trapped via combustion using the Leeman Labs Hydra-C mercury analyzer and analyzed for both mass-independent and mass-dependent signatures using cold vapor multi-collector inductively coupled plasma mass spectrometry (CV-MC-ICP-MS). Detectable variations in the Hg isotopic signatures were apparent across our field sites, suggesting stable isotopic analysis has great potential to trace contamination pathways in waterways. Preliminary data demonstrate Hg from the ASGM site has unique isotopic signatures that are seen downstream. However, the impacted lake sediments do not have the mining signature despite having three times more Hg than the non-impacted lake. Based on this data, it may be possible to trace Hg from ASGM and assess whether it is impacting local ecosystems and food webs. Hair and soil samples will also be discussed. This demonstration is essential for the broader application of these tools for understanding and applying Hg isotopic analysis in other

  7. HgTe-based photodetectors in Poland

    Science.gov (United States)

    Rogalski, A.

    2009-05-01

    The purpose of this paper is to review the main achievements in the investigations of HgTe-based ternary alloys and point out the Polish contributions in development of the middle and long wavelength infrared photodetectors. Research and development efforts in Poland were concentrated mostly on uncooled market niche. At the beginning, a modified isothermal vapor phase epitaxy has been used for research and commercial fabrication of photoconductive, photoelectromagnetic, and other HgCdTe devices. Bulk growth and liquid phase epitaxy were also used. Recently, the fabrication of infrared devices relies on low temperature epitaxial technique, namely metalorganic vapor phase deposition. At present stage of development, the photoconductive and photoelectromagnetic (PEM) detectors are gradually replaced with photovoltaic devices which offer inherent advantages of no electric or magnetic bias, no heat load and no flicker noise. Potentially, photodiodes offer high performance and very fast response. However, conventional photovoltaic uncooled detectors suffer from low quantum efficiency and very low junction resistance. The problems have been solved with advanced band gap engineered architecture, multiple cell heterojunction devices connected in series, and monolithic integration of the detectors with microoptics. In final part of the paper, the Polish achievements in technology and performance of HgMnTe and HgZnTe photodetectors are presented.

  8. Magnetic fields of HgMn stars

    DEFF Research Database (Denmark)

    Hubrig, S.; Gonzalez, J. F.; Ilyin, I.;

    2012-01-01

    Context. The frequent presence of weak magnetic fields on the surface of spotted late-B stars with HgMn peculiarity in binary systems has been controversial during the two last decades. Recent studies of magnetic fields in these stars using the least-squares deconvolution (LSD) technique have fai...

  9. Bioavailability of Cd, Zn and Hg in Soil to Nine Recombinant Luminescent Metal Sensor Bacteria

    OpenAIRE

    Olesja Bondarenko; Taisia Rõlova; Anne Kahru; Angela Ivask

    2008-01-01

    A set of nine recombinant heavy metal-specific luminescent bacterial sensors belonging to Gram-negative (Escherichia and Pseudomonas) and Gram-positive (Staphylococcus and Bacillus) genera and containing various types of recombinant metalresponse genetic elements was characterized for heavy metal bioavailability studies. All nine strains were induced by Hg and Cd and five strains also by Zn. As a lowest limit, the sensors were detecting 0.03 μg·L-1 of Hg, 2 μg·L-1 of Cd and 400 Î...

  10. Isotopic Composition of Gaseous Elemental Mercury in the Free Troposphere of the Pic du Midi Observatory, France.

    Science.gov (United States)

    Fu, Xuewu; Marusczak, Nicolas; Wang, Xun; Gheusi, François; Sonke, Jeroen E

    2016-06-01

    Understanding the sources and transformations of mercury (Hg) in the free troposphere is a critical aspect of global Hg research. Here we present one year of observations of atmospheric Hg speciation and gaseous elemental Hg (GEM) isotopic composition at the high-altitude Pic du Midi Observatory (2860 m above sea level) in France. Biweekly integrated GEM from February 2012 to January 2013 revealed significant variations in δ(202)HgGEM (-0.04‰ to 0.52‰) but not in Δ(199)HgGEM (-0.17‰ to -0.27‰) or Δ(200)HgGEM (-0.10‰ to 0.05‰). δ(202)HgGEM was negatively correlated with CO and reflected air mass origins from Europe (high CO, low δ(202)HgGEM) and from the Atlantic Ocean (low CO, high δ(202)HgGEM). We suggest that the δ(202)HgGEM variations represent mixing of recent low δ(202)HgGEM European anthropogenic emissions with high δ(202)HgGEM northern hemispheric background GEM. In addition, Atlantic Ocean free troposphere air masses showed a positive correlation between δ(202)HgGEM and gaseous oxidized Hg (GOM) concentrations, indicative of mass-dependent Hg isotope fractionation during GEM oxidation. On the basis of atmospheric δ(202)HgGEM and speciated Hg observations, we suggest that the oceanic free troposphere is a reservoir within which GEM is readily oxidized to GOM. PMID:27214126

  11. Physical and Chemical Parameters of HgMn Stars on the Basis of the Available Data

    Science.gov (United States)

    Ghazaryan, Satenik

    2014-12-01

    For better understanding the details of physical processes affecting essentially the atmosphere of HgMn stars, I compiled the chemical abundances of nearly all the observed HgMn stars and compared them with Smith's review (1996). During this study for about 130 stars of the mentioned type, more than 65 elements' abundances were compiled and rescaled assuming solar abundances values given by Asplund (2009). This compilation results show that the heavy elements are systematically overabundant in HgMn stars (see Preston (1974) and Smith (1996)). The under abundance of HeI seems less pronounced than in Smith's review. For some elements (As, Br, Rh, Pd, Gd, Au, and U) no abundances have been shown by Smith while for the others, the results are mostly the same. Thus we arrive at a conclusion that these results are in good agreement with Smith's figure. But it is important to know that the created database is not homogenous because the HgMn stars were observed by different techniques and dissimilar methods. Consequently, the uncertainties need to be taken into account to be sure for each abundance value. It is planned also to combine the abundances of all observed A and B stars as well to be able to see the abundance stratifications changes because of the effective temperature. This work is in preparation and will be done in near future.

  12. A study of capillary discharge lamps in Ar-Hg and Xe-Hg mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Denisova, N [Institute of Theoretical and Applied Mechanics, Novosibirsk, Institutskaja str. 4/1 (Russian Federation); Gavare, Z; Revalde, G; Skudra, Ja; Veilande, R [Institute of Atomic Physics and Spectroscopy, University of Latvia, Raina blvd. 19, Riga (Latvia)

    2011-04-20

    Low-pressure capillary discharge lamps in Ar-Hg and Xe-Hg mixtures are studied. The discharge size is 0.5 mm (500 {mu}m) in radius. According to the literature, such types of plasma sources are classified as microplasmas. The studies include spectrally resolved optical measurements, tomographic reconstructions and numerical simulations using the collisional-radiative model for an Ar-Hg plasma. We discuss the problems of theoretical modelling and experimental diagnostics of microplasma sources. It is shown that the conventional collisional-radiative model, based on the assumption that transportation of atoms in the highly excited states can be neglected, has limitations in modelling a capillary discharge in an Ar-Hg mixture. It is found that diffusion of highly excited mercury atoms to the wall influences the emission properties of the capillary discharge. We have concluded that applications of the emission tomography method to microplasmas require a special analysis in each particular case.

  13. Carbon and other light element contents in the Earth's core based on first-principles molecular dynamics.

    Science.gov (United States)

    Zhang, Yigang; Yin, Qing-Zhu

    2012-11-27

    Carbon (C) is one of the candidate light elements proposed to account for the density deficit of the Earth's core. In addition, C significantly affects siderophile and chalcophile element partitioning between metal and silicate and thus the distribution of these elements in the Earth's core and mantle. Derivation of the accretion and core-mantle segregation history of the Earth requires, therefore, an accurate knowledge of the C abundance in the Earth's core. Previous estimates of the C content of the core differ by a factor of ∼20 due to differences in assumptions and methods, and because the metal-silicate partition coefficient of C was previously unknown. Here we use two-phase first-principles molecular dynamics to derive this partition coefficient of C between liquid iron and silicate melt. We calculate a value of 9 ± 3 at 3,200 K and 40 GPa. Using this partition coefficient and the most recent estimates of bulk Earth or mantle C contents, we infer that the Earth's core contains 0.1-0.7 wt% of C. Carbon thus plays a moderate role in the density deficit of the core and in the distribution of siderophile and chalcophile elements during core-mantle segregation processes. The partition coefficients of nitrogen (N), hydrogen, helium, phosphorus, magnesium, oxygen, and silicon are also inferred and found to be in close agreement with experiments and other geochemical constraints. Contents of these elements in the core derived from applying these partition coefficients match those derived by using the cosmochemical volatility curve and geochemical mass balance arguments. N is an exception, indicating its retention in a mantle phase instead of in the core. PMID:23150591

  14. Chemical beam epitaxy of CdTe, HgTe, and HgCdTe

    Energy Technology Data Exchange (ETDEWEB)

    Benz, R.G. II; Wagner, B.K.; Rajavel, D.; Summers, C.J. (Physical Sciences Lab., Georgia Tech Research Inst., Atlanta, GA (USA))

    1991-05-01

    A chemical beam epitaxy (CBE) system has been implemented for the growth of CdTe, HgTe, and their alloys. The system is briefly described. Results on the cracking of the organometallic source gases are presented. Epitaxial layers have been grown from gas sources of diethylcadmium, diisopropyltelluride and Hg vapor, as well as conventional solid sources. Optical and electrical properties are reported, demonstrating the potential of CBE for growing high quality solar cell and infrared detector material. (orig.).

  15. Thermally switchable dispersions of thermochromic Ag2HgI4 nanoparticles.

    Science.gov (United States)

    Schwiertz, Janine; Geist, André; Epple, Matthias

    2009-04-28

    Thermochromic Ag(2)HgI(4) nanoparticles were prepared by rapid precipitation from aqueous solution. Stable colloids were formed by coating the particles with four different polymers, respectively. The four resulting systems of functionalised Ag(2)HgI(4) nanoparticles were characterised with respect to their polymer content (elemental analysis), particle size (dynamic light scattering, scanning electron microscopy), optical properties in dispersion (UV spectroscopy), crystallinity (X-ray powder diffraction), and thermochromic transition temperature (differential scanning calorimetry) and also compared to the unfunctionalised bulk phase Ag(2)HgI(4). Stable dispersions with a reversible temperature-induced colour change from yellow to orange (T(trs) = 25-40 degrees C) were obtained. PMID:19352519

  16. Statistical analysis from recent abundance determinations in HgMn stars

    Science.gov (United States)

    Ghazaryan, S.; Alecian, G.

    2016-08-01

    To better understand the hot chemically peculiar group of HgMn stars, we have considered a compilation of a large number of recently published data obtained for these stars from spectroscopy. We compare these data to the previous compilation by Smith. We confirm the main trends of the abundance peculiarities, namely the increasing overabundances with increasing atomic number of heavy elements, and their large spread from star to star. For all the measured elements, we have looked for correlations between abundances and effective temperature (Teff). In addition to the known correlation for Mn, some other elements are found to show some connection between their abundances and Teff. We have also checked if multiplicity is a determinant parameter for abundance peculiarities determined for these stars. A statistical analysis using a Kolmogorov-Smirnov test shows that the abundances anomalies in the atmosphere of HgMn stars do not present significant dependence on the multiplicity.

  17. Efficient removal and highly selective adsorption of Hg2+ by polydopamine nanospheres with total recycle capacity

    International Nuclear Information System (INIS)

    Highlights: • The PDA nanospheres with uniform diameter of 150–200 nm were used to remove Hg2+ efficiently and selectively. • The desorption capacity of PDA nanospheres was 100% in pH 1. • The structure and removal capacity of PDA nanospheres remained almost unchanged after recycling five times. - Abstract: This study reported a new method for efficient removal of Hg2+ from contaminated water using highly selective adsorptive polydopamine (PDA) nanospheres, which were uniform and had a small diameter (150–200 nm). The adsorption isotherms, kinetics, thermodynamics were investigated. Also, the effects of ionic strength, co-existing ions on removing ability of PDA nanospheres for Hg2+ were studied. Adsorption of Hg2+ was very fast and efficient as adsorption equilibrium was completed within 4 h and the maximum adsorption capacities were 1861.72 mg/g, 2037.22 mg/g, and 2076.81 mg/g at 298 K, 313 K, and 328 K respectively, increasing with increasing of temperature. The PDA nanospheres exhibited highly selective adsorption of Hg2+ and had a total desorption capacity of 100% in hydrochloric acid solution, pH 1. The results showed that the structure of PDA nanospheres remained almost unchanged after recycling five times. Furthermore, X-ray photoelectron spectroscopy (XPS) was employed to determine the elements of PDA nanospheres before and after Hg2+ adsorption. Considering their efficient and highly Hg2+ selective adsorption, total recycle capacity, and high stability, PDA nanospheres will be feasible in a number of practical applications

  18. Long-term Hg pollution induced Hg tolerance in the terrestrial isopod Porcellio scaber (Isopoda, Crustacea)

    International Nuclear Information System (INIS)

    The aim of our work was to assess the pollution-induced community tolerance (PICT) of isopod gut microbiota and pollution-induced isopod population tolerance (PIPT). Animals collected from a chronically Hg polluted and an unpolluted location were exposed for 14 days to 10 μg Hg/g dry food under laboratory conditions. The lysosomal membrane stability, hepatopancreas epithelium thickness, feeding activity and animal bacterial gut microbiota composition were determined. The results confirm the hypothesis that the response to short-term Hg exposure differs for animals from the Hg polluted and the unpolluted field locations. The animals and their gut microbiota from the Hg polluted location were less affected by Hg in a short-term feeding experiment than those from the unpolluted environment. We discuss the pollution-induced population tolerance of isopods and their gut microbiota as a measure of effects of long-term environmental pollution. The ecological consequences of such phenomena are also discussed. - Isopods (Porcellio scaber) as well as their bacterial gut community from a mercury-polluted site are mercury tolerant

  19. Long-term Hg pollution induced Hg tolerance in the terrestrial isopod Porcellio scaber (Isopoda, Crustacea)

    Energy Technology Data Exchange (ETDEWEB)

    Lapanje, A. [University of Ljubljana, Biotechnical Faculty, Department of Biology, Vecna pot 111, 1000 Ljubljana (Slovenia); Institute of Physical Biology, Veliko Mlacevo 59, 1290 Grosuplje (Slovenia)], E-mail: ales.lapanje@bf.uni-lj.si; Drobne, D. [University of Ljubljana, Biotechnical Faculty, Department of Biology, Vecna pot 111, 1000 Ljubljana (Slovenia); Nolde, N. [Institute Jozef Stefan, Department of Environmental Sciences, Jamova 39, 1000 Ljubljana (Slovenia); Valant, J. [University of Ljubljana, Biotechnical Faculty, Department of Biology, Vecna pot 111, 1000 Ljubljana (Slovenia); Muscet, B. [Institute of Physical Biology, Veliko Mlacevo 59, 1290 Grosuplje (Slovenia); Leser, V. [University of Ljubljana, Biotechnical Faculty, Department of Biology, Vecna pot 111, 1000 Ljubljana (Slovenia); Rupnik, M. [Institute of Public Health, Prvomajska 1, 2000 Maribor (Slovenia); Faculty of Medicine, University of Maribor, Slomskov trg 15, 2000 Maribor (Slovenia)

    2008-06-15

    The aim of our work was to assess the pollution-induced community tolerance (PICT) of isopod gut microbiota and pollution-induced isopod population tolerance (PIPT). Animals collected from a chronically Hg polluted and an unpolluted location were exposed for 14 days to 10 {mu}g Hg/g dry food under laboratory conditions. The lysosomal membrane stability, hepatopancreas epithelium thickness, feeding activity and animal bacterial gut microbiota composition were determined. The results confirm the hypothesis that the response to short-term Hg exposure differs for animals from the Hg polluted and the unpolluted field locations. The animals and their gut microbiota from the Hg polluted location were less affected by Hg in a short-term feeding experiment than those from the unpolluted environment. We discuss the pollution-induced population tolerance of isopods and their gut microbiota as a measure of effects of long-term environmental pollution. The ecological consequences of such phenomena are also discussed. - Isopods (Porcellio scaber) as well as their bacterial gut community from a mercury-polluted site are mercury tolerant.

  20. Exposures of dental professionals to elemental mercury and methylmercury.

    Science.gov (United States)

    Goodrich, Jaclyn M; Chou, Hwai-Nan; Gruninger, Stephen E; Franzblau, Alfred; Basu, Niladri

    2016-01-01

    Mercury (Hg) exposure, a worldwide public health concern, predominantly takes two forms--methylmercury from fish consumption and elemental Hg from dental amalgam restorations. We recruited 630 dental professionals from an American Dental Association meeting to assess Hg body burden and primary sources of exposure in a dually exposed population. Participants described occupational practices and fish consumption patterns via questionnaire. Hg levels in biomarkers of elemental Hg (urine) and methylmercury (hair and blood) were measured with a Direct Mercury Analyzer-80 and were higher than the general US population. Geometric means (95% CI) were 1.28 (1.19-1.37) μg/l in urine, 0.60 (0.54-0.67) μg/g in hair and 3.67 (3.38-3.98) μg/l in blood. In multivariable linear regression, personal amalgams predicted urine Hg levels along with total years in dentistry, amalgams handled, working hours and sex. Fish consumption patterns predicted hair and blood Hg levels, which were higher among Asians compared with Caucasians. Five species contributed the majority of the estimated Hg intake from fish--swordfish, fresh tuna, white canned tuna, whitefish and king mackerel. When studying populations with occupational exposure to Hg, it is important to assess environmental exposures to both elemental Hg and methylmercury as these constitute a large proportion of total exposure. PMID:26329138

  1. A physiological role for HgII during phototrophic growth

    Science.gov (United States)

    Grégoire, D. S.; Poulain, A. J.

    2016-02-01

    The bioaccumulation of toxic monomethylmercury is influenced by the redox reactions that determine the amount of mercury (Hg) substrate--HgII or Hg0 (refs ,)--that is available for methylation. Phototrophic microorganisms can reduce HgII to Hg0 (ref. ). This reduction has been linked to a mixotrophic lifestyle, in which microbes gain energy photosynthetically but acquire diverse carbon compounds for biosynthesis from the environment. Photomixotrophs must maintain redox homeostasis to disperse excess reducing power due to the accumulation of reduced enzyme cofactors. Here we report laboratory experiments in which we exposed purple bacteria growing in a bioreactor to HgII and monitored Hg0 concentrations. We show that phototrophs use HgII as an electron sink to maintain redox homeostasis. Hg0 concentrations increased only when bacteria grew phototrophically, and when bacterial enzyme cofactor ratios indicated the presence of an intracellular redox imbalance. Under such conditions, bacterial growth rates increased with increasing HgII concentrations; when alternative electron sinks were added, Hg0 production decreased. We conclude that Hg can fulfil a physiological function in bacteria, and that photomixotrophs can modify the availability of Hg to methylation sites.

  2. Hg Vetical Transference in Soil—Water System

    Institute of Scientific and Technical Information of China (English)

    GUOYIJUN; MOUSUSEN; 等

    1998-01-01

    Hg vertial transference in soil-water system was studied by analyzing Hg vertical ditribution in soil column after adding Hg and one of the two leacheates,deionzied water or acid rain,into soil column.The results indicated that Hg was hardly transferable in puple soil.About 86%-88% of the total soil Hg was distributed in the top layer (0-2cm) and to Hg was detected in the leakage when the purple soil column was leached by deionized water and simulated acid rain.But Hg was more movalbe in yellow soil with only about 20%-22% of the total soil Hg distributed in the top layer (0-2cm),and about 17%-25% washed out from the soil column by deionized water and simulted acid rain,Incremant in soil bulk density colud reduce Hg leaching,thus the more the Hg kept in soil,the less the Hg leached into underground water,Deionized water and acid rain almost played the same role in leaching Hg.Bentioint was most effecient in preventing Hg from vertcal transferring in the soil coulumn.

  3. Bioavailability of Cd, Zn and Hg in Soil to Nine Recombinant Luminescent Metal Sensor Bacteria

    Directory of Open Access Journals (Sweden)

    Olesja Bondarenko

    2008-11-01

    Full Text Available A set of nine recombinant heavy metal-specific luminescent bacterial sensors belonging to Gram-negative (Escherichia and Pseudomonas and Gram-positive (Staphylococcus and Bacillus genera and containing various types of recombinant metalresponse genetic elements was characterized for heavy metal bioavailability studies. All nine strains were induced by Hg and Cd and five strains also by Zn. As a lowest limit, the sensors were detecting 0.03 μg·L-1 of Hg, 2 μg·L-1 of Cd and 400 μg·L-1 of Zn. Limit of determination of the sensors depended mostly on metal-response element, whereas the toxicity of those metals towards the sensor bacteria was mostly dependent on the type of the host bacterium, with Gram-positive strains being more sensitive than Gram-negative ones. The set of sensors was used to evaluate bioavailability of Hg, Cd and Zn in spiked soils. The bioavailable fraction of Cd and Zn in soil suspension assay (2.6 – 5.1% and 0.32 – 0.61%, of the total Cd and Zn, respectively was almost comparable for all the sensors, whereas the bioavailability of Hg was about 10-fold higher for Gram-negative sensor cells (30.5% of total Hg, compared to Gram-positive ones (3.2% of the total Hg. For Zn, the bioavailable fraction in soil-water suspensions and respective extracts was comparable (0.37 versus 0.33% of the total Zn. However, in the case of Cd, for all the sensors used and for Hg concerning only Gram-negative sensor strains, the bioavailable fraction in soilwater suspensions exceeded the water-extracted fraction about 14-fold, indicating that upon direct contact, an additional fraction of Cd and Hg was mobilized by those sensor bacteria. Thus, for robust bioavailability studies of heavy metals in soils any type of genetic metal-response elements could be used for the construction of the sensor strains. However, Gram-positive and Gram-negative senor strains should be used in

  4. MBE HgCdTe heterostructure detectors

    Science.gov (United States)

    Schulman, Joel N.; Wu, Owen K.

    1990-01-01

    HgCdTe has been the mainstay for medium (3 to 5 micron) and long (10 to 14 micron) wavelength infrared detectors in recent years. Conventional growth and processing techniques are continuing to improve the material. However, the additional ability to tailor composition and placement of doped layers on the tens of angstroms scale using molecular beam epitaxy (MBE) provides the opportunity for new device physics and concepts to be utilized. MBE-based device structures to be discussed here can be grouped into two categories: tailored conventional structures and quantum structures. The tailored conventional structures are improvements on familiar devices, but make use of the ability to create layers of varying composition, and thus band gap, at will. The heterostructure junction can be positioned independently of doping p-n junctions. This allows the small band gap region in which the absorption occurs to be separated from a larger band gap region in which the electric field is large and where unwanted tunneling can occur. Data from hybrid MBE/liquid phase epitaxy (LPE)/bulk structures are given. Quantum structures include the HgTe-CdTe superlattice, in which the band gap and transport can be controlled by alternating thin layers (tens of angstroms thick) of HgTe and CdTe. The superlattice has been shown to exhibit behavior which is non-alloy like, including very high hole mobilities, two-dimensional structure in the absorption coefficient, resonant tunneling, and anisotropic transport.

  5. Atmospheric emissions estimation of Hg, As, and Se from coal-fired power plants in China, 2007.

    Science.gov (United States)

    Tian, Hezhong; Wang, Yan; Xue, Zhigang; Qu, Yiping; Chai, Fahe; Hao, Jiming

    2011-07-15

    Over half of coal in China is burned directly by power plants, becoming an important source of hazardous trace element emissions, such as mercury (Hg), arsenic (As), and selenium (Se), etc. Based on coal consumption by each power plant, emission factors classified by different boiler patterns and air pollution control devices configuration, atmospheric emissions of Hg, As, and Se from coal-fired power plants in China are evaluated. The national total emissions of Hg, As, and Se from coal-fired power plants in 2007 are calculated at 132 t, 550 t, and 787 t, respectively. Furthermore, according to the percentage of coal consumed by units equipped with different types of PM devices and FGD systems, speciation of mercury is estimated as follows: 80.48 t of Hg, 49.98 t of Hg(2+), and 1.89 t of Hg(P), representing 60.81%, 37.76%, and 1.43% of the totals, respectively. The emissions of Hg, As, and Se in China's eastern and central provinces are much higher than those in the west, except for provinces involved in the program of electricity transmission from west to east China, such as Sichuan, Guizhou, Yunnan, Shaanxi, etc. PMID:21621816

  6. Interpretation of the vacancy-ordering controlled growth morphology of Hg5In2Te8 precipitates in Hg3In2Te6 single crystals by TEM observation and crystallographic calculation

    International Nuclear Information System (INIS)

    Graphical abstract: The growth morphology and detailed crystallography of Hg5In2Te8 precipitates in Hg3In2Te6 matrix to has been interpreted by means of transmission electron microscopy and invariant element deformation model. Three crystallographic equivalent variants of Hg5In2Te8 precipitates in Hg3In2Te6 matrix were found to have different growth directions and habit planes. Such growth morphology is fully attributed to the lattice shrinkage induced by vacancy ordering under high temperature in Hg5In2Te8. Through near coincident site lattice and invariant strain calculation, the morphology and crystallographic features of the precipitate has been successfully interpreted. - Highlights: • The growth morphology of Hg5In2Te8 precipitates in Hg3In2Te6 was observed by TEM. • Near-CSL calculation show 0.7577% lattice shrinkage of Hg5In2Te8 at high temperature. • All the involved factors have inverse relationship with the move speed of interface. • The calculated crystallography features of Hg5In2Te8 agree well with the TEM results. - Abstract: Generally, the crystal growth morphology in liquid or vapor was controlled by chemical potential, while that in solid solute was restricted by 3D strain matching between matrix and secondary phase. It is already known that the growth and evolution of the morphology of secondary phase during the solid phase transformation are highly determined by the variation of interface energy induced by lattice mismatch. In this work, the growth morphology and crystallography of Hg5In2Te8 precipitates in Hg3In2Te6 matrix were investigated by means of transmission electron microscopy (TEM). It was found that the growth of Hg5In2Te8 precipitates displayed an unusual growth morphology which contain three crystallographically equivalent variants with different growth directions in Hg3In2Te6 matrix, suggesting a slight lattice constant variation of Hg5In2Te8 precipitate during the phase transformation at high temperature, which is

  7. 40 CFR 60.4124 - Hg budget permit revisions.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Hg budget permit revisions. 60.4124... Coal-Fired Electric Steam Generating Units Permits § 60.4124 Hg budget permit revisions. Except as provided in § 60.4123(b), the permitting authority will revise the Hg Budget permit, as necessary,...

  8. First Observations of Laser-Excited Hg3 and Hg2RG Spectra in a Supersonic Expansion Beam

    Science.gov (United States)

    Koperski; Atkinson; Krause

    1998-02-01

    Triatomic van der Waals complexes of mercury have been observed in a supersonic expansion beam crossed with a laser beam to produce excitation and fluorescence spectra. The expansion beam consisting of mercury and a (noble) carrier gas (RG) was excited in three separate spectral regions: in the vicinity of the Hg 2537 A intercombination line, near the (forbidden) Hg 6(3)P2 <-- 6(1)S0 atomic transition (2200-2290 A), and in the region of the Hg2 G0(+)u <-- X0(+)g transition (1975-2080 A). The resulting spectra, which were recorded in the spectral range 1900-6000 A, contained, in addition to the known Hg, Hg2, and HgRG components, new absorption and fluorescence bands that are ascribed to Hg2RG and Hg3 complexes. Copyright 1998 Academic Press. Copyright 1998Academic Press PMID:9473437

  9. On the valence state of Hg in (Hg, Cr)Sr2CuO4+δ superconductor

    International Nuclear Information System (INIS)

    The 1201-type of superconducting samples of nominal composition (Hg0.7Cr0.3)Sr2CuO4+δ, were synthesised in partial vacuum and subsequently annealed in oxygen and argon. The Tc onset for the different samples is found to be ∼58 K. Hg LIII-edge measurements have clearly shows that Hg is in divalent state in all the (Hg,Cr)-1201 samples. (author)

  10. Study of Hg vacancies in (Hg,Cd)Te after THM growth and post-growth annealing by positron annihilation

    OpenAIRE

    Krause, R.; Klimakow, A.; Kießling, F. M.; Polity, A.; Gille, Peter; Schenk, M.

    1990-01-01

    Positron lifetime measurements have been performed to study vacancy defects in Hg0.78Cd0.22Te. Post-growth annealing under various Hg vapour pressure conditions have been used to create a well-defined number of Hg vacancies. The sensitivity range of the positron annihilation method was found to be 1015 < cHgvac

  11. Fully relativistic coupled cluster and DFT study of electric field gradients at Hg in 199Hg compounds

    DEFF Research Database (Denmark)

    Arcisauskaité, Vaida; Knecht, Stefan; Sauer, Stephan P. A.;

    2012-01-01

    We investigate the magnitude and interplay of relativistic and electron correlation effects on the electric field gradient (EFG) at the position of Hg in linear and bent HgL2 (L=CH3, Cl, Br, I) and trigonal planar [HgCl3]- complexes using four-component relativistic Dirac-Coulomb (DC) and non...

  12. Exploiting the higher specificity of silver amalgamation: selective detection of mercury(II) by forming Ag/Hg amalgam.

    Science.gov (United States)

    Deng, Li; Ouyang, Xiangyuan; Jin, Jianyu; Ma, Cheng; Jiang, Ying; Zheng, Jing; Li, Jishan; Li, Yinhui; Tan, Weihong; Yang, Ronghua

    2013-09-17

    Heavy metal ion pollution poses severe risks in human health and the environment. Driven by the need to detect trace amounts of mercury, this article demonstrates, for the first time, that silver/mercury amalgamation, combining with DNA-protected silver nanoparticles (AgNPs), can be used for rapid, easy and reliable screening of Hg(2+) ions with high sensitivity and selectivity over competing analytes. In our proposed approach, Hg(2+) detection is achieved by reducing the mercury species to elemental mercury, silver atoms were chosen as the mercury atoms' acceptors by forming Ag/Hg amalgam. To signal fluorescently this silver amalgamation event, a FAM-labeled ssDNA was employed as the signal reporter. AgNPs were grown on the DNA strand that resulted in greatly quenching the FAM fluorescence. Formation of Ag/Hg amalgam suppresses AgNPs growth on the DNA, leading to fluorescence signal increase relative to the fluorescence without Hg(2+) ions, as well as marked by fluorescence quenching. This FAM fluorescence enhancement can be used for detection of Hg(2+) at the a few nanomolar level. Moreover, due to excellent specificity of silver amalgamation with mercury, the sensing system is highly selective for Hg(2+) and does not respond to other metal ions with up to millimolar concentration levels. This sensor is successfully applied to determination of Hg(2+) in tap water, spring water and river water samples. The results shown herein have important implications in the development of new fluorescent sensors for the fast, easy, and selective detection and quantification of Hg(2+) in environmental and biological samples. PMID:23937672

  13. Experimental study on Hg{sup 0} removal from flue gas over columnar MnO{sub x}-CeO{sub 2}/activated coke

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Yine [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082 (China); Li, Caiting, E-mail: ctli@hnu.edu.cn [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082 (China); Zhao, Lingkui; Zhang, Jie; Zeng, Guangming; Zhang, Xunan; Zhang, Wei; Tao, Shasha [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control, Hunan University, Ministry of Education, Changsha 410082 (China)

    2015-04-01

    Highlights: • The Hg{sup 0} removal efficiency over columnar MnCe6/activated coke up to 94%. • MnO{sub x} and CeO{sub 2} exhibited a significant synergistic role in Hg{sup 0} removal over MnCe/AC. • Lattice oxygen, chemisorbed oxygen and OH groups on the surface of MnCe/AC contributed to Hg{sup 0} oxidation. • Hg{sup 0} removal mechanisms over MnCe/AC were identified firstly. - Abstract: Mn-Ce mixed oxides supported on commercial columnar activated coke (MnCe/AC) were employed to remove elemental mercury (Hg{sup 0}) at low temperatures (100–250 °C) without the assistance of HCl in flue gas. The samples were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), X-ray photoelectron spectroscopy (XPS) and temperature programmed desorption (TPD). Effects of some factors, including Mn-Ce loading values, active component, reaction temperatures and flue gas components (O{sub 2}, SO{sub 2}, NO, H{sub 2}O), on Hg{sup 0} removal efficiency were investigated. Results indicated that the optimal Mn-Ce loading value and reaction temperature were 6% and 190 °C, respectively. Considerable high Hg{sup 0} removal efficiency (>90%) can be obtained over MnCe6/AC under both N{sub 2}/O{sub 2} atmosphere and simulated flue gas atmosphere at 190 °C. Besides, it was observed that O{sub 2} and NO exerted a promotional effect on Hg{sup 0} removal, H{sub 2}O exhibited a suppressive effect, and SO{sub 2} hindered Hg{sup 0} removal seriously when in the absence of O{sub 2}. Furthermore, the XPS spectra of Hg 4f and Hg-TPD results showed that the captured mercury were existed as Hg{sup 0} and HgO on the MnCe6/AC, and HgO was the major species, which illustrated that adsorption and catalytic oxidation process were included for Hg{sup 0} removal over MnCe6/AC, and catalytic oxidation played the critical role. What's more, both lattice oxygen and chemisorbed oxygen or OH groups on MnCe6/AC contributed to Hg{sup 0} oxidation. MnCe6/AC, which exhibited

  14. Stabilizing Role of Metallophilic HgII ... HgII Interactions in Nucleic Acids

    Czech Academy of Sciences Publication Activity Database

    Benda, Ladislav; Tanaka, Y.; Sychrovský, Vladimír; Straka, Michal

    Praha: -, 2011. s. 35-35. [Quantum Bioinorganic Chemistry Conference /3./. 25.06.2011-28.06.2011, Český Krumlov] R&D Projects: GA ČR GA203/09/2037; GA ČR GAP205/10/0228 Grant ostatní: European Reintegration Grant(XE) 230955 Institutional research plan: CEZ:AV0Z40550506 Keywords : metallophilic HgII ... HgII interactions * mispairing nucleic acids * metallophilic interactions Subject RIV: CF - Physical ; Theoretical Chemistry

  15. Development of Se and Hg determination methods in woman's hair

    International Nuclear Information System (INIS)

    INAA method of mercury (Hg) and selenium (Se) determination was carried out by using comparison factor of 75Se peak at 264.4 keV and 279.2 keV using Ge (Li) detector EG and G Ortec and 8100 MCA Canberra. The average of the factor was 2,35. The samples were pregnane women's hair from DIY. The direction of this investigation was to find data for further monitoring of contamination and the health of baby will be born. DIY was chosen because not much of industries and DIY is not fishing region. It is known that many kind of industries product Hg contaminant, and fish usually contain high concentration of Hg. The results are: 1. Hg concentration was 0,32 - 5,20 ppm and the Se = 0,43 - 6,08 ppm. Hg can be detected in all of the samples, and only in one sample that Se can not be find. 2. Fish consumer : Hg = 0,32 - 5,2 ppm and Se = 0 - 194 ppm. The controls : Hg = 0,32 - 2,03 ppm and Se 0,57 - 6,08 ppm. 3. Employer : Hg 0,52 - 5,04 ppm and Se = 0,59 - 1,94 ppm. Control : Hg = 0,32 - 5,20 ppm and Se = 0,43 - 2,94 ppm. It can be concluded that: I. comparison factor is 2,35. The factor can be used for Hg calculation with 7,6 % accuracy for Hg and 3,31 % for se. This results of the Hg and se concentration can be used for the further contamination and health monitoring. Most of the se/Hg comparison were 1 : 1. It means the se concentration was similar with the Hg. (author)

  16. Heavy metal tolerance (Cr, Ag and Hg in bacteria isolated from sewage

    Directory of Open Access Journals (Sweden)

    Agostinho A. de Lima e Silva

    2012-12-01

    Full Text Available Samples of sewage from a university hospital and a chemistry technical school were analysed for the percentage of bacterial tolerance to chromium (Cr, silver (Ag and mercury (Hg. Additionally, we investigated the effect of these metals on pigmentation and on some enzymatic activities of the metal tolerant strains isolated, as well as antimicrobial resistance in some metal tolerant Enterobacteriaceae strains. Tolerance to Cr was observed mainly in Gram positive bacteria while in the case of Ag and Hg the tolerant bacteria were predominately Gram negative. Hg was the metal for which the percentage of tolerance was significantly higher, especially in samples from the hospital sewage (4.1%. Mercury also had the most discernible effect on color of the colonies. Considering the effect of metals on the respiratory enzymes, one strain of Ag-tolerantBacillus sp. and one of Hg-tolerant P. aeruginosa were unable to produce oxidase in the presence of Ag and Hg, respectively, while the expression of gelatinase was largely inhibited in various Gram negative strains (66% by Cr. Drug resistance in Hg-tolerant Enterobacteriaceae strains isolated from the university hospital sewage was greater than 80%, with prevalence of multiple resistance, while the Ag-tolerant strains from the same source showed about 34% of resistance, with the predominance of mono-resistance. Our results showed that, despite the ability of metal tolerant strains to survive and grow in the presence of these elements, the interactions with these metals may result in metabolic or phisiological changes in this group of bacteria.

  17. Allyl- iso-propyltelluride, a new MOVPE precursor for CdTe, HgTe and (Hg,Cd)Te

    Science.gov (United States)

    Hails, Janet E.; Cole-Hamilton, David J.; Stevenson, John; Bell, William

    2000-06-01

    The use of allyl- iso-propyltelluride as the tellurium precursor for the growth of CdTe, HgTe and (Hg,Cd)Te by metal organic vapour-phase epitaxy has been investigated. It has proved to be an efficient source of tellurium with growth rates for HgTe and (Hg,Cd)Te of up to 10 μm h -1 at 300°C. The best CdTe was grown at 4.5 μm h -1 under Me 2Cd-rich conditions at 300°C in the presence of Hg vapour.

  18. Analysis of As, Cr and Hg in crude oil sludge by using instrumental neutron activation analysis (INAA)

    International Nuclear Information System (INIS)

    Environment are carrying toxic elements. The aim of this study was to determine As, Cr and Hg elements in crude oil sludge. In this study, crude oil sludge samples from a refining plant at Kerteh, Terengganu was carried out using Instrumental Neutron Activation Analysis (INAA). The samples were packed and irradiated at the Malaysian Nuclear Agency reactor TRIGA Mark II. Later, the samples were counted using a HPGe detector and were analyzed using the SAMPO 90 software. The certified reference material (CRM) namely NBS Coal Fly Ash 1633a was used as a standard to obtain the concentration average using a comparative method. A total of 11 elements (i.e. As, Co, Cr, Fe, Ga, Hg, Mn, Na, Sc, Se and Sr) were determined in all samples. The concentrations of As, Cr and Hg were found to be in the range of 0-18.8, 98.2-124 and 52.8-57.9 μg.g-1 respectively. From the concentration of these elements, the results showed that the value for total As element is low but the values for the total Cr and Hg are considerable higher than the permissible value. However, almost all the potential environmental impacts can be controlled by sludge disposal options such as well-designed, carefully, efficiently and continuously managed, by following accepted guidelines and regulations. (Author)

  19. Novel M(II)-Hg(II) coordination polymers generated from metal-containing building blocks M(2-pyrazinecarboxylate) 2 · (H 2O) 2 (M=Cu, Ni, Co) and HgCl 2

    Science.gov (United States)

    Dong, Yu-Bin; Smith, Mark D.; zur Loye, Hans-Conrad

    2000-12-01

    A new class of M(II)-Hg(II) (M=Cu(II), Co(II), Ni(II)) mixed-metal coordination polymers, Cu(2-pyrazinecarboxylate) 2HgCl 2 ( 4), [Co(2-pyrazinecarboxylate) 2(HgCl 2) 2] · 0.61H 2O ( 5) and [Ni(2-pyrazinecarboxylate) 2(HgCl 2) 2] · 0.77H 2O ( 6), have been prepared by self assembly of metal-containing building blocks, M(2-pyrazinecarboxylate) 2 · (H 2O) 2 (M=Cu(II), Co(II), Ni(II)), with HgCl 2. Compounds 4- 6 were characterized fully by IR, elemental analysis and single crystal X-ray diffraction. Compound 4 crystallized in the monoclinic space group C2/ c, with a=17.916(5) Å, b=7.223(2) Å, c=13.335(4) Å, β=128.726(3)°, V=1346.2(6) Å 3, Z=4. It contains alternating Hg(II) and Cu(II) metal centers that are cross-linked by 2-pyrazinecarboxylate spacers and chlorine co-ligands to generate a unique three-dimensional Hg(II)-Cu(II) mixed metal framework. Compound 5 crystallized in the triclinic space group P1¯, with a=6.3879(7) Å, b=6.6626(8) Å, c=13.2286(15) Å, α=96.339(2)°, β=91.590(2)°, γ=113.462(2)°, V=511.71(10) Å 3, Z=1. Compound 6 also crystallized in the triclinic space group P1¯, with a=6.3543(8) Å, b=6.6194(8) Å, c=13.2801(16) Å, α=96.449(2)°, β=92.263(2)°, γ=113.541(2)°, V=506.67(11) Å 3, Z=1. Compounds 5 and 6 are isostructural and in the solid state the Hg(II)⋯M(II)⋯Hg(II) units are connected by Hg 2Cl 2 linkages to produce a novel M(II)-Hg(II) (MCo(II), Ni(II)) zigzag mixed-metal chain, in which a new type of M-M'-M'-M array was observed. The metal containing building blocks, M(2-pyrazinecarboxylate) 2 · (H 2O) 2 (MCu(II), Co(II), Ni(II)), exhibit different connectivities to HgCl 2 depending on the metal cation contained within them.

  20. Source attribution and process analysis for atmospheric mercury in East China simulated by CMAQ-Hg

    OpenAIRE

    Zhu, J.; Wang, T.; J. Bieser; V. Matthias

    2015-01-01

    The contribution from different emission sources and atmospheric processes to gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM), particulate bound mercury (PBM) and mercury deposition in East China were quantified using the Community Multi-scale Air Quality (CMAQ-Hg) modeling system run with nested grid resolution of 27 km. Natural source (NAT) and six categories of anthropogenic mercury sources (ANTH) including cement production (CEM), domestic life (DOM), indus...

  1. Source attribution and process analysis for atmospheric mercury in eastern China simulated by CMAQ-Hg

    OpenAIRE

    Zhu, J.; Wang, T.; J. Bieser; V. Matthias

    2015-01-01

    The contribution from different emission sources and atmospheric processes to gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM), particulate bound mercury (PBM) and mercury deposition in eastern China were quantified using the Community Multi-scale Air Quality (CMAQ-Hg) modeling system run with a nested domain. Natural sources (NAT) and six categories of anthropogenic mercury sources (ANTH) including cement production (CEM), domestic life (DOM), industrial boil...

  2. Design of a ROIC for scanning type HgCdTe LWIR focal plane arrays

    OpenAIRE

    Yazıcı, Melik; Yazici, Melik; Kayahan, Hüseyin; Kayahan, Huseyin; Ceylan, Ömer; Ceylan, Omer; Gürbüz, Yaşar; Gurbuz, Yasar

    2010-01-01

    Design of a silicon readout integrated circuit (ROIC) for LWIR HgCdTe Focal Plane is presented. ROIC incorporates time delay integration (TDI) functionality over seven elements with a supersampling rate of three, increasing SNR and the spatial resolution. Novelty of this topology is inside TDI stage; integration of charges in TDI stage implemented in current domain by using switched current structures that reduces required area for chip and improves linearity performance. ROIC, in terms of...

  3. Mass loading of Hg in the Monte Amiata mining district, Southern Tuscany (Italy)

    OpenAIRE

    Rimondi V.; Costagliola P.; Gray J. E.; Lattanzi P.; Nannucci M.; Salvadori A.; Vaselli O.

    2013-01-01

    Mercury (Hg) transport in natural environments is of concern because Hg bioaccumulates in the food web. Particularly methyl-Hg is the form of Hg of major concern as it is highly toxic to humans and is ingested through food consumption, dominantly fish. Quantification of Hg mass loads in watersheds draining Hg mine districts allows (1) the identification of sources of contamination, (2) the evaluation of the effect of Hg on the environment, and (3) the identification of processes affecting Hg ...

  4. Synthesis, Characterization and Thermal Studies of Zn(II), Cd(II) and Hg(II) Complexes of N-Methyl-N-Phenyldithiocarbamate: The Single Crystal Structure of [(C6H5)(CH3)NCS2]4Hg2

    Science.gov (United States)

    Onwudiwe, Damian C.; Ajibade, Peter A.

    2011-01-01

    Zn(II), Cd(II) and Hg(II) complexes of N-methyl-N-phenyl dithiocarbamate have been synthesized and characterized by elemental analysis and spectral studies (IR, 1H and 13C-NMR). The single crystal X-ray structure of the mercury complex revealed that the complex contains a Hg centre with a distorted tetrahedral coordination sphere in which the dinuclear Hg complex resides on a crystallographic inversion centre and each Hg atom is coordinated to four S atoms from the dithiocarbamate moiety. One dithiocarbamate ligand acts as chelating ligand while the other acts as chelating bridging ligand between two Hg atoms, resulting in a dinuclear eight-member ring. The course of the thermal degradation of the complexes has been investigated using thermogravimetric and differential thermal analyses techniques. Thermogravimetric analysis of the complexes show a single weight loss to give MS (M = Zn, Cd, Hg) indicating that they might be useful as single source precursors for the synthesis of MS nanoparticles and thin films. PMID:21673933

  5. Phase equilibria and thermodynamic functions for Ag–Hg and Cu–Hg binary systems

    International Nuclear Information System (INIS)

    Highlights: ► The thermodynamic properties of Ag–Hg and Cu–Hg are explored in order to facilitate dental materials design. ► A self-consistent set of thermodynamic parameters is obtained. ► The experimental information can be well reproduced by the optimized thermodynamic data. - Abstract: In order to facilitate the computational design of new amalgams for novel dental alloys, the phase equilibria, phase diagrams and thermodynamic functions for Ag–Hg and Cu–Hg binary systems are explored in this work, based on the CALPHAD framework and experimental characterizations. The Gibbs free energies of the solution phases as well as the stoichiometric phases are calculated, with the aid of enthalpies of mixing, activities, enthalpies of formation, and phase equilibrium data. The thermodynamic descriptions provided in this work enable the stabilities of each phase at various temperatures and compositions to be well described, which contribute to the establishment of a general database to design novel metallic dental materials.

  6. 199Hg Parameters in thymine-Hg-thymine metal mediated base pair

    Czech Academy of Sciences Publication Activity Database

    Daraku, T.; Furuita, K.; Šebera, Jakub; Yamanaka, D.; Kondo, Y.; Ono, A.; Katahira, R.; Bickelhaupt, F. M.; Sychrovský, Vladimír; Kojima, C.; Tanaka, Y.

    Rio de Janeiro : -, 2013. s. 84-84. [ISMAR Meeting /18./ - NMR Users Meeting /14./ - Iberoamerican NMR Meeting Biomedical Imaging Symposium /5./. 19.05.2013-24.05.2013, Rio de Janeiro] R&D Projects: GA ČR GAP205/10/0228 Institutional support: RVO:61388963 Keywords : NMR * T-Hg-T * J-coupling Subject RIV: CF - Physical ; Theoretical Chemistry

  7. Elucidation of the defence mechanism in microalgae Chlorella sorokiniana under mercury exposure. Identification of Hg-phytochelatins.

    Science.gov (United States)

    Gómez-Jacinto, Verónica; García-Barrera, Tamara; Gómez-Ariza, José Luis; Garbayo-Nores, Inés; Vílchez-Lobato, Carlos

    2015-08-01

    Algae and aquatic macrophytes are capable of accumulating heavy metals up to concentrations several orders of magnitude higher than those existing in their surrounding environment. Investigation of mercury toxicology in microalgae is of great interest from ecological point of view, since they could be used as bioindicator to evaluate aquatic ecosystems affected by Hg pollution. In this study, we have performed an exposure experiment focused on the biological response of microalgae Chlorella sorokiniana, a unicellular model organism, to Hg-induced toxicity. The culture was exposed to different concentrations of this element for nine days, namely 0.5, 1, 5 and 10mg L(-1) of HgCl2 (as Hg). To achieve a better understanding of the biological mechanisms triggered by Hg-induced toxicity in this alga a metallomic approach based on SEC-ICP-ORS-MS was applied to survey biomarkers of biological response to mercury contamination in surface water. In addition, the combination of RP-HPLC-ICP-ORS-MS and RP-HPLC-ESI-QqQ-TOF-MS was applied to identify, for the first time, two Hg-binding phytochelatins in this aquatic organism, using cell extracts from microalgae exposed to inorganic mercury. PMID:26079052

  8. Heavy metal separation from water-mercury (Hg/sup +2/)

    International Nuclear Information System (INIS)

    An alloy with the empirical formula MgFeSi was studied. It contained 6-9% magnesium and it removed cadmium and elements lower in the electromotive series. The removal ability was based on the magnesium content of the alloy. However, in removing mercury, the alloy appeared to have ability to go beyond the magnesium content and continued to remove additional mercury. This presented a dilemma until the x-ray diffraction data were analyzed. The results showed that magnesium ferrosilicon was primarily Mg/sub 2/Si and FeSi/sub 2/ with minor amounts of FeSi or a mixture. It was then assumed that the initial reaction was: Mg/sub 2/Si+2Hg/sup +2/→2Hg/sup O/+2Mg/sup +2/+Si/sup O/ and the secondary reaction: FeSi/sub 2/+Hg/sup +2/→Hg/sup O/+Fe/sup +2/+2Si/sup O/ which would account for the additional mercury removal ability. Previous work had indicated that the 50% ferrosilicon alloy (FeSi/sub 2/) while being nearly selective for mercury would also remove small amounts of arsenic and copper when present. The arsenic and copper were presumed to be removed by the scavenging effect of ferric iron present from the aerial oxidation of the ferrous iron formed when the 50% ferrosilicon reacted

  9. Shock-induced changes in HgO powder

    International Nuclear Information System (INIS)

    Powder compacts of HgO were subjected to explosively-generated shock-wave loading in Sandia Bear fixtures and recovered for analysis. Although XRD powder spectra show only the orthorhombic form of HgO in both the as-received and recovered samples, XRD line profiles and TEM indicate up to an order of magnitude increase in crystallite size. Magnetic data reveal a superconducting transition below 4.2 K that is attributed to metallic α-Hg formed by a partial, shock-induced decomposition of the HgO, consistent with TEM identification of α-Hg particles using a cold stage. In addition, paramagnetic impurities present in the as-received HgO powder appear to be partially converted to a ferromagnetic or ferrimagnetic phase that dominates the magnetic properties of the recovered powder. The amounts of both the superconducting and ferromagnetic phases vary strongly with position within the shock recovery capsules

  10. Superconductivity above 100 K in compounds containing Hg

    International Nuclear Information System (INIS)

    The results of studies of new Hg based cuprate superconductors are reported. Several members of a new family of (Hg,Tl)(Ba,Sr)Can-2CunOx high temperature superconductors have been synthesized. These compounds, which are analogs to the Hg-Ba-Ca- and Tl-Ba-Ca- layered cuprates, are multi-phased and have superconducting transition temperatures above 100 K. Incorporation of Hg appears to stabilize several of the Tl-compounds, including a double layer Tl/Sr system, in a manner similar to the role that Pb plays in the Tl/Sr- and Bi/Sr-systems. It has been suggested that recent reports of resistive Tc's above 200 K in Hg based samples are due to the presence of free Hg. Magnetization measurements of such a sample confirm this hypothesis

  11. Oxidative stress in MeHg-induced neurotoxicity

    Energy Technology Data Exchange (ETDEWEB)

    Farina, Marcelo, E-mail: farina@ccb.ufsc.br [Departamento de Bioquimica, Centro de Ciencias Biologicas, Universidade Federal de Santa Catarina, Florianopolis, SC (Brazil); Aschner, Michael [Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN (United States); Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN (United States); Rocha, Joao B.T., E-mail: jbtrocha@yahoo.com.br [Departamento de Quimica, Centro de Ciencias Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS (Brazil)

    2011-11-15

    Methylmercury (MeHg) is an environmental toxicant that leads to long-lasting neurological and developmental deficits in animals and humans. Although the molecular mechanisms mediating MeHg-induced neurotoxicity are not completely understood, several lines of evidence indicate that oxidative stress represents a critical event related to the neurotoxic effects elicited by this toxicant. The objective of this review is to summarize and discuss data from experimental and epidemiological studies that have been important in clarifying the molecular events which mediate MeHg-induced oxidative damage and, consequently, toxicity. Although unanswered questions remain, the electrophilic properties of MeHg and its ability to oxidize thiols have been reported to play decisive roles to the oxidative consequences observed after MeHg exposure. However, a close examination of the relationship between low levels of MeHg necessary to induce oxidative stress and the high amounts of sulfhydryl-containing antioxidants in mammalian cells (e.g., glutathione) have led to the hypothesis that nucleophilic groups with extremely high affinities for MeHg (e.g., selenols) might represent primary targets in MeHg-induced oxidative stress. Indeed, the inhibition of antioxidant selenoproteins during MeHg poisoning in experimental animals has corroborated this hypothesis. The levels of different reactive species (superoxide anion, hydrogen peroxide and nitric oxide) have been reported to be increased in MeHg-exposed systems, and the mechanisms concerning these increments seem to involve a complex sequence of cascading molecular events, such as mitochondrial dysfunction, excitotoxicity, intracellular calcium dyshomeostasis and decreased antioxidant capacity. This review also discusses potential therapeutic strategies to counteract MeHg-induced toxicity and oxidative stress, emphasizing the use of organic selenocompounds, which generally present higher affinity for MeHg when compared to the classically

  12. Mass loading of Hg in the Monte Amiata mining district, Southern Tuscany (Italy

    Directory of Open Access Journals (Sweden)

    Rimondi V.

    2013-04-01

    Full Text Available Mercury (Hg transport in natural environments is of concern because Hg bioaccumulates in the food web. Particularly methyl-Hg is the form of Hg of major concern as it is highly toxic to humans and is ingested through food consumption, dominantly fish. Quantification of Hg mass loads in watersheds draining Hg mine districts allows (1 the identification of sources of contamination, (2 the evaluation of the effect of Hg on the environment, and (3 the identification of processes affecting Hg transport. This study focuses on the determination of Hg loads in the Paglia River, which drains the Hg district of Monte Amiata (Italy, world’s 4th largest Hg producing district. Mass loads were determined for total Hg, particulate Hg, and dissolved Hg. Data obtained from two sampling campaigns carried out in 2011 indicated that up to 34 g/d of Hg were transported during the rainy season, of which up to 99% was as particulate Hg. Maximum Hg loads were related to runoff from the Abbadia San Salvatore mine (ASSM, and thus, this mine is the main source of Hg to the Paglia River basin. Data indicate that particulate Hg has been deposited along with river sediment, forming a natural sink where resultant chemical reactions promote conversion of Hg from particulate matter to dissolved Hg. These results suggest that mining of Hg has affected this area. Even today, 30 years after the cessation of mining, considerable amounts of Hg are continuously transported downstream from mined areas by local rivers.

  13. Superdeformation studies in {sup 191}Hg

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, M.P.; Janssens, R.V.F.; Crowell, B. [and others

    1995-08-01

    Superdeformation in the A {approximately} 190 region was first observed in {sup 191}Hg from an experiment performed at ATLAS using the Argonne Notre Dame {gamma}-ray facility. We recently revisited the study of superdeformation in this nucleus using Gammasphere and the {sup 160}Gd({sup 36}S,5n) and {sup 174}Yb({sup 22}Ne,5n) reactions at 172 and 120 MeV in order to populate and measure states in the second well. The goal of the experiment was to identify new bands in the data, and thus allow us to gain understanding on the relative placement of single particle orbitals near the N = 112 SD shell gap. From an analysis of the data, the three previously identified SD bands were extended, and their feeding into the yrast states delineated. Two new SD bands were observed and preliminary evidence for a third new band was obtained as well.

  14. HgCdTe monolithic infrared detector

    Energy Technology Data Exchange (ETDEWEB)

    Yakushev, Maxim V.; Dvoretsky, Sergei A.; Kozlov, Alexander I.; Sabinina, Irina V.; Sidorov, Yu.G.; Sorochkin, Alexander V.; Fomin, Boris I.; Aseev, Alexander L. [A.V. Rzhanov Institute of Semiconductor Physics, Siberian Branch RAS, Novosibirsk (Russian Federation)

    2010-06-15

    We report the processes of fabricating monolithic 32 x 32 infrared detector based on (310) HgCdTe/CdTe/ZnTe/ Si photosensitive heterostructure which was grown by a molecular-beam epitaxy technique in the free surface of ROIC cells. Optimum parameters of the technological processes were determined. The minimum temperature of preepitaxial thermal annealing in vacuum of ROIC was determined as 450 C. The dark and photo current-voltage characteristics were measured and analyzed. A good sensitivity of diodes was observed. The product R{sub 0} x A {proportional_to} 10{sup 5} Ohm x cm{sup 2}. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. HD 30963: a new HgMn star

    CERN Document Server

    Monier, R; Royer, F

    2016-01-01

    Using high dispersion high quality spectra of HD 30963 obtained with the echelle spectrograph SOPHIE at Observatoire de Haute Provence in November 2015, we show that this star, hitherto classified as a B9 III superficially normal star, is actually a new Chemically Peculiar star of the HgMn type. Spectrum synthesis reveals large overabundances of Mn, Sr, Y, Zr , Pt and Hg and pronounced underabundances of He and Ni which are characteristic of HgMn stars. We therefore propose that this interesting object be reclassified as a B9 HgMn star.

  16. HgCdTe e-avalanche photodiode detector arrays

    OpenAIRE

    Anand Singh; Shukla, A. K.; Ravinder Pal

    2015-01-01

    Initial results on the MWIR e-APD detector arrays with 30 μm pitch fabricated on LPE grown compositionally graded p-HgCdTe epilayers are presented. High dynamic resistance times active area (R0A) product 2 × 106 Ω-cm2, low dark current density 4 nA/cm2 and high gain 5500 at -8 V were achieved in the n+-υ-p+ HgCdTe e-APD at 80 K. LPE based HgCdTe e-APD development makes this technology amenable for adoption in the foundries established for the conventional HgCdTe photovoltaic detector arrays w...

  17. Hg-coordination studies of oligopeptides containing cysteine, histidine and tyrosine by $^{199m}$Hg-TDPAC

    CERN Document Server

    Ctortecka, B; Mallion, S; Butz, T; Hoffmann, R

    1999-01-01

    In order to study the interaction of histidine- and tyrosine- containing peptide chains with Hg(II), the nuclear quadrupole interaction (NQI) of /sup 199m/Hg in the Hg complexes of the oligopeptides alanyl-alanyl-histidyl-alanyl-alanine-amid (AAHAA-NH /sub 2/) and alanyl-alanyl-tyrosyl-alanyl-alanine-amid (AAYAA-NH/sub 2/) was determined by time differential perturbed angular correlation and is compared with previous data on alanyl-alanyl-cysteyl-alanyl- alanyl (AACAA-OH). The /sup 199m/Hg-NQIs depend on the oligopeptide to Hg(II) stoichiometry and indicate that two-fold and four-fold coordinations occur for the bound Hg(II). (12 refs).

  18. Dynamical evolution of titanium, strontium, and yttrium spots on the surface of the HgMn star HD 11753

    OpenAIRE

    Briquet, Maryline; Korhonen, H.; González, J.F.; Hubrig, S.; Hackman, T.

    2010-01-01

    Aims: We gathered about 100 high-resolution spectra of three typical HgMn (mercury-manganese) stars, HD 11753, HD 53244, and HD 221507, to search for slowly pulsating B-like pulsations and surface inhomogeneous distribution of various chemical elements. Methods: Classical frequency analysis methods were used to detect line profile variability and to determine the variation period. Doppler imaging reconstruction was performed to obtain abundance maps of chemical elements on the stellar surfa...

  19. 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.

  20. Laser induced fluorescence (LIF) of Hg sub 2 and Hg sub 3 via dissociation of HgBr sub 2 at 157 nm

    Energy Technology Data Exchange (ETDEWEB)

    Skordoulis, C.; Sarantopoulou, E.; Spyrou, S.M.; Kosmidis, C.; Cefalas, A.C. (National Hellenic Research Foundation, Athens (Greece). Inst. of Theoretical and Physical Chemistry)

    1991-02-01

    Laser induced fluorescence of the mercury clusters Hg{sub 2} and Hg{sub 3} in the spectral range between 300 nm to 510 nm has been obtained from the dissociation of HgBr{sub 2} at 7.88 eV (157.5 nm) with an F{sub 2} molecular laser, together with fluorescence from mercury atomic transitions from highly excited states. The excitation process involves two photon absorption which dissociates the molecule at 15.76 eV total photon energy with the subsequent formation of the metallic clusters. (orig.).

  1. Hg SOIL GAS AND Hg SOIL DISTRIBUTION AROUND FORMER „ZRINSKI“ MINE ON MT. MEDVEDNICA, CROATIA

    OpenAIRE

    2008-01-01

    The purpose of this study is to present the field and laboratory researches, statistical analyses and graphical displays of the results of Hg soil gas and Hg soil distribution in the area around former mining site „Zrinski“ on Mt. Medvednica. The values of overall Hg concentrations in the soil gas show lognormal distribution, and their spatial distribution outlines the connection with the present Pb-Ag-Zn mineralization and confirms anthropogenic origin of uneven landscape relief (waste rock ...

  2. Factors influencing the large-scale distribution of Hg° in the Mexico City area and over the North Pacific

    OpenAIRE

    D. Blake; S. Vay; Sachse, G.; Browell, E.; Avery, M.; J. Dibb; E. Scheuer; H. Mao; Talbot, R.; Huey, G.; H. Fuelberg

    2007-01-01

    Gas-phase elemental mercury (Hg°) was measured aboard the NASA DC-8 aircraft during the Intercontinental Chemical Transport Experiment Phase B (INTEX-B) campaign in spring 2006. Flights were conducted around Mexico City and on two subsequent deployments over the North Pacific based out of Honolulu, Hawaii and Anchorage, Alaska. Data obtained from 0.15–12 km altitude showed that Hg° exhibited a relatively constant vertical profile centered around 100 ppqv. Highly concentrated pol...

  3. Factors influencing the large-scale distribution of Hg° in the Mexico City area and over the North Pacific

    OpenAIRE

    Talbot, R.; H. Mao; E. Scheuer; J. Dibb; Avery, M.; Browell, E.; Sachse, G.; S. Vay; D. Blake; Huey, G.; H. Fuelberg

    2008-01-01

    Gas-phase elemental mercury (Hg°) was measured aboard the NASA DC-8 aircraft during the Intercontinental Chemical Transport Experiment Phase B (INTEX-B) campaign in spring 2006. Flights were conducted around Mexico City and on two subsequent deployments over the North Pacific based out of Honolulu, Hawaii and Anchorage, Alaska. Data obtained from 0.15–12 km altitude showed that Hg° exhibited a relatively constant vertical profile centered around 100 ppqv. Highl...

  4. Factors influencing the large-scale distribution of Hg° in the Mexico City area and over the North Pacific

    OpenAIRE

    Talbot, R.; H. Mao; E. Scheuer; J. Dibb; Avery, M.; Browell, E.; Sachse, G.; S. Vay; D. Blake; Huey, G.; H. Fuelberg

    2008-01-01

    International audience Gas-phase elemental mercury (Hg°) was measured aboard the NASA DC-8 aircraft during the Intercontinental Chemical Transport Experiment Phase B (INTEX-B) campaign in spring 2006. Flights were conducted around Mexico City and on two subsequent deployments over the North Pacific based out of Honolulu, Hawaii and Anchorage, Alaska. Data obtained from 0.15?12 km altitude showed that Hg° exhibited a relatively constant vertical profile centered around 100 ppqv. Highly conc...

  5. Milk secretion of 203Hg after administration of 203Hg-methylmercuric chloride and its metabolism in lactating goats

    International Nuclear Information System (INIS)

    In order to study the mechanism of milk contamination with mercury compounds, a single dose of 203Hg-labeled methylmercury chloride was administered intravenously to three lactating goats. The secretion into milk, and urinary and fecal excretion of 203Hg were determined for 21 days after the administration. The 203Hg concentration in milk reached the highest level of 7 x 10-1 ppm 7 hr. after the administration, followed by slow decrease with time to 2 x 10-1 ppm 21 days after the administration. The total amount of 203Hg secreted into milk for 21 days reached 0.4% of the dose. 203Hg distribution in cream, casein and whey was 0.2, 0.1 and 0.09% of the dose, respectively. 203Hg was mainly excreted into feces, and amounted 29% of the dose for 21 days, whereas 2.3% was excreted into urine. The 203Hg level in blood cells was larger than blood serum. Among the organs of the animals sacrificed 21 days after the administration, kidney showed the highest concentration of 0.01%/g, while liver had the largest distribution of 6% of the dose. Further, the biological half-life of 203Hg after the administration of 203Hg-labeled methylmercury chloride was calculated to be 40.5 days in the lactating goats. (Kobatake, H.)

  6. Atmospheric gaseous elemental mercury (GEM) concentrations and mercury depositions at a high-altitude mountain peak in south China

    OpenAIRE

    X. W. Fu; Feng, X.; Dong, Z. Q.; R. S. Yin; Wang, J. X.; Yang, Z. R.; Zhang, H.

    2010-01-01

    China is regarded as the largest contributor of mercury (Hg) to the global atmospheric Hg budget. However, concentration levels and depositions of atmospheric Hg in China are poorly known. Continuous measurements of atmospheric gaseous elemental mercury (GEM) were carried out from May 2008 to May 2009 at the summit of Mt. Leigong in south China. Simultaneously, deposition fluxes of THg and MeHg in precipitation, throughfall and litterfall were also studied. Atmospheric GEM concentrations aver...

  7. Analysis of Moderately Siderophile Elements in Angrites: Implications for Core Formation of the Angrite Parent Body

    Science.gov (United States)

    Righter, K.; Shirai, N.; Irving, A.J.

    2009-01-01

    Angrites are an enigmatic group of achondrites, that constitute the largest group of basalts not affiliated with the Moon, Mars or Vesta (HEDs). Chemically, angrites are exceptionally refractory element- enriched (e.g., Al, Ca) and volatile element-depleted (e.g., Na and K) achondrites. Highly volatile siderophile and chalcophile elements (Zn, Ge and Se) may be less depleted than alkalis and Ga taken to imply a fractionation of plagiophile elements. Core formation on the angrite parent body (APB) is not well understood due to the dearth of moderately siderophile element (Ga, Ge, Mo, Sb, W) data for angrites, with the exception of Ni and Co [2]. In particular, there are no data for Mo abundances of angrites, while Sb and W abundances are reported for only 3 angrites, and have not always been determined on the same sample. The recent increase in angrite numbers (13) has greatly increased our knowledge of the compositional diversity of the angrite parent body (APB). In this study, we report new Co, Ni, Ga, Mo, Sb and W abundances for angrites by laser ablation inductively coupled plasma mass spectrometry (ICP-MS) in order to place constraints on core formation of the APB.

  8. Production of radio-isotopes 197Hg and 198Au from 198Hg

    International Nuclear Information System (INIS)

    Studies on excitation functions of neutron induced reactions are of considerable importance for testing nuclear models as well as for practical applications. Mercury can be a suitable material for spallation neutron source in an accelerator driven system (ADS) if corrosion, due to chemical wetting, gradient mass transfer, and high density heat generation are taken care of. In order to design the target system, estimation of induced activity in the target is important among other factors. In an ADS this radioactivity is induced by neutrons along with that by the primary projectile. An ADS is operated at a few GeV beam energy, but often logistic studies are carried out at much lower energies. Quantitative knowledge of the induced activity at such operating parameters is important for proper planning of the experiments. The aim of the present work is to determine the excitation functions of 198Hg (n, 2n) 197Hg and 198Hg (n, p) 198Au reactions for 1-50 MeV energy using statistical and pre-equilibrium nuclear reaction model codes. This will help us to determine the total yield and induced activities due to these radio nuclides. The computed excitation functions are compared with and the reported measured data and cross sections from ENDF database

  9. Assessment of Cu, Pb and Hg Contamination in Bottom Sediments Of Surface Water in XuZhou

    Institute of Scientific and Technical Information of China (English)

    王晓; 韩宝平; 朱雪强

    2004-01-01

    Pollution of heavy metals Cu,Pb and Hg is assessed using geo-accumulation index in this paper. The result shows that the bottom sediments of surface water in Xuzhou is polluted by these heavy metals to deferent degrees, of which the Jinma River is the most serious, and then the Kuihe River, the abandoned Yellow River, and the Jinghang Canal. The Yunlong Lake has also been polluted by Hg. The three kinds of heavy metals in the order of concentration is Hg>Cu>Pb. The pollution degree and the type of element is closely related with industrial structure in Xuzhou.

  10. The Liquid-Liquid Extraction of Toxic Metals (Cd, Hg and Pb by Calixarenes

    Directory of Open Access Journals (Sweden)

    D. Max Roundhill

    2009-12-01

    Full Text Available Toxic metals (Cd, Hg and Pb are mostly present in the environment due to natural phenomenon and human activities as well. Exposure of these non-essential elements in the environment causes severe effects. They are known to cause problems in humans as well as in aquatic life. In this work, we demonstrate various studies regarding liquid-liquid extraction of selected ions with different functionalized calixarenes. This review article briefly discusses several molecular designs of calixarenes for divalent ion (Cd2+, Hg2+ and Pb2+ recognition; as well as the relationship between structure and selectivity of the macrocycles is elaborated. The article does not, however, attempt to cover all of the different approaches to these toxic metal ions extraction.

  11. 46 CFR 53.01-5 - Scope (modifies HG-100).

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Scope (modifies HG-100). 53.01-5 Section 53.01-5... General Requirements § 53.01-5 Scope (modifies HG-100). (a) The regulations in this part apply to steam... IV of the ASME Boiler and Pressure Vessel Code (incorporated by reference; see 46 CFR 53.01-1)....

  12. Capture of air particulate matter and gaseous Hg0 by ionic liquids analyzed by PIXE

    International Nuclear Information System (INIS)

    Particle induced X-ray emission (PIXE) has been extensively employed to study the elements associated to air particulate matter (Pm). However, the atmosphere is a very complex system and inorganic pollutants may be also in gaseous phases. Aerosol monitoring does not allow the determination of all the volatile inorganic compounds, since they are not retained in the filters, or if they are trapped, the analysis under vacuum results in a partial or total loss of them. In order to extend the applications of PIXE there is a need to develop new methods to simultaneously capture particulate matter and volatile substances. Ionic liquids (Il) result from combinations of organic cations and anions that may be liquid at room temperature. The physicochemical characteristics of Il s allow them to absorb atmospheric trace metals present in solid and gaseous phases, a task normally performed with independent sampling methods. In this work we explored this capability of Il s as monitors of chemical species which can be found in the gas phase and as particulate matter. The tested Il s included 1-Butyl-3-Methyl-Imidazolium-Hexafluorophosphate (BMIM) (PF6) for Pm and Hg capture; and 1-Butyl-3-methylimidazolium thiocyanate (BMIM) (Scn) only for Hg capture. Elemental analysis of both experiments was performed by particle induced X-ray emission (PIXE). Changes in the molecular structure on BMIM PF6 due to the Hg binding were followed by infrared spectroscopy. (BMIM( (PF6) proved to be successful as passive collector of Pm. However when both were used for Hg capture, (BMIM) (Scn) showed better selectivity. These preliminary results showed the potential of Il s for simultaneous uptake of Pm and volatile inorganic compounds. (Author)

  13. An in-depth evaluation of accuracy and precision in Hg isotopic analysis via pneumatic nebulization and cold vapor generation multi-collector ICP-mass spectrometry.

    Science.gov (United States)

    Rua-Ibarz, Ana; Bolea-Fernandez, Eduardo; Vanhaecke, Frank

    2016-01-01

    Mercury (Hg) isotopic analysis via multi-collector inductively coupled plasma (ICP)-mass spectrometry (MC-ICP-MS) can provide relevant biogeochemical information by revealing sources, pathways, and sinks of this highly toxic metal. In this work, the capabilities and limitations of two different sample introduction systems, based on pneumatic nebulization (PN) and cold vapor generation (CVG), respectively, were evaluated in the context of Hg isotopic analysis via MC-ICP-MS. The effect of (i) instrument settings and acquisition parameters, (ii) concentration of analyte element (Hg), and internal standard (Tl)-used for mass discrimination correction purposes-and (iii) different mass bias correction approaches on the accuracy and precision of Hg isotope ratio results was evaluated. The extent and stability of mass bias were assessed in a long-term study (18 months, n = 250), demonstrating a precision ≤0.006% relative standard deviation (RSD). CVG-MC-ICP-MS showed an approximately 20-fold enhancement in Hg signal intensity compared with PN-MC-ICP-MS. For CVG-MC-ICP-MS, the mass bias induced by instrumental mass discrimination was accurately corrected for by using either external correction in a sample-standard bracketing approach (SSB) or double correction, consisting of the use of Tl as internal standard in a revised version of the Russell law (Baxter approach), followed by SSB. Concomitant matrix elements did not affect CVG-ICP-MS results. Neither with PN, nor with CVG, any evidence for mass-independent discrimination effects in the instrument was observed within the experimental precision obtained. CVG-MC-ICP-MS was finally used for Hg isotopic analysis of reference materials (RMs) of relevant environmental origin. The isotopic composition of Hg in RMs of marine biological origin testified of mass-independent fractionation that affected the odd-numbered Hg isotopes. While older RMs were used for validation purposes, novel Hg isotopic data are provided for the

  14. Temperature behaviour of Raman spectra in the Cs2HgBr4, Cs2HgCl4 crystals

    International Nuclear Information System (INIS)

    Polarized Raman spectra of the Cs2HgBr4 and Cs2HgCl4 crystals are obtained and analyzed at different temperatures in the range of 300-2 K. The similarity of the structural transformations in the both crystals is established

  15. Characterization of CdTe, HgTe, and Hg1-xCdxTe grown by chemical beam epitaxy

    Science.gov (United States)

    Wagner, B. K.; Rajavel, D.; Benz, R. G.; Summers, C. J.

    1991-10-01

    Detailed characterization of chemical beam epitaxially (CBE) grown CdTe and Hg1-xCdxTe layers are reported. These characterizations include photoluminescence, infrared transmission, energy dispersive x-ray analysis, and variable temperature (10-300 K) Hall effect and resistivity measurements. The results indicate that high quality HgCdTe layers can be grown by CBE.

  16. Reduced leakage currents of CdZnTe radiation detectors with HgTe/HgCdTe superlattice contacts

    Science.gov (United States)

    Chang, Y.; Grein, C. H.; Becker, C. R.; Huang, J.; Ghosh, S.; Aqariden, F.; Sivananthan, S.

    2012-10-01

    Room-temperature-operating CdZnTe radiation detectors have high energy resolution, linear energy response and are capable of operating in normal counting and spectroscopic modes, hence are highly desirable for medical diagnosis, nondestructive industrial evaluations, homeland security, counterterrorism inspections and nuclear proliferation detection to ensure national and international nuclear safety. HgTe/HgCdTe superlattices can be designed to selectively transport one carrier species while hindering transport of the other. Specifically, one designs a large carrier effective mass for undesired carriers in the electric field direction, which results in low carrier velocities, and yet a density of states for undesired carrier that is lower than that of a comparable bulk semiconductor, which results in low carrier concentrations, hence a low current density under an electric field. The opposite carrier species can be designed to have a large velocity and high density of states, hence producing a large current density. By employing HgTe/HgCdTe superlattices as contact layers intermediate between CdZnTe absorbers and metal contacts, leakage currents under high electric fields are reduced and improved x-ray and γ-ray detector performance is anticipated. Pixilated CdZnTe radiation detectors arrays were fabricated and characterized to evaluate the effectiveness of HgTe/HgCdTe superlattices in reducing leakage currents. Current-voltage characteristics show that HgTe/HgCdTe superlattice contact layers consistently result in significantly reduced leakage currents relative to detectors with only metal contacts.

  17. Efficient removal and highly selective adsorption of Hg{sup 2+} by polydopamine nanospheres with total recycle capacity

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiulan [School of Chemistry and Chemical Engineering, Key Laboratory for Green Processing of Chemical Engineering of Xinjiang bingtuan, Shihezi University, Shihezi 832003 (China); Jia, Xin, E-mail: jiaxin@shzu.edu.cn [School of Chemistry and Chemical Engineering, Key Laboratory for Green Processing of Chemical Engineering of Xinjiang bingtuan, Shihezi University, Shihezi 832003 (China); Zhang, Guoxiang [Gansu Dayu Water-saving Group Co., Ltd, Jiuquan 735000 (China); Hu, Jiamei; Sheng, Wenbo; Ma, Zhiyuan; Lu, Jianjiang; Liu, Zhiyong [School of Chemistry and Chemical Engineering, Key Laboratory for Green Processing of Chemical Engineering of Xinjiang bingtuan, Shihezi University, Shihezi 832003 (China)

    2014-09-30

    Highlights: • The PDA nanospheres with uniform diameter of 150–200 nm were used to remove Hg{sup 2+} efficiently and selectively. • The desorption capacity of PDA nanospheres was 100% in pH 1. • The structure and removal capacity of PDA nanospheres remained almost unchanged after recycling five times. - Abstract: This study reported a new method for efficient removal of Hg{sup 2+} from contaminated water using highly selective adsorptive polydopamine (PDA) nanospheres, which were uniform and had a small diameter (150–200 nm). The adsorption isotherms, kinetics, thermodynamics were investigated. Also, the effects of ionic strength, co-existing ions on removing ability of PDA nanospheres for Hg{sup 2+} were studied. Adsorption of Hg{sup 2+} was very fast and efficient as adsorption equilibrium was completed within 4 h and the maximum adsorption capacities were 1861.72 mg/g, 2037.22 mg/g, and 2076.81 mg/g at 298 K, 313 K, and 328 K respectively, increasing with increasing of temperature. The PDA nanospheres exhibited highly selective adsorption of Hg{sup 2+} and had a total desorption capacity of 100% in hydrochloric acid solution, pH 1. The results showed that the structure of PDA nanospheres remained almost unchanged after recycling five times. Furthermore, X-ray photoelectron spectroscopy (XPS) was employed to determine the elements of PDA nanospheres before and after Hg{sup 2+} adsorption. Considering their efficient and highly Hg{sup 2+} selective adsorption, total recycle capacity, and high stability, PDA nanospheres will be feasible in a number of practical applications.

  18. SI-traceable measurement of methylmercury in tuna by species-specific isotope dilution with a 202Hg isotopically enriched methylmercury reference material

    International Nuclear Information System (INIS)

    The Comite Consultatif pour la Quantite de Matiere, CCQM, from the International Committee for Weights and Measures, has the tasks to co-ordinate the activities of national metrology laboratories in establishing traceability of measurements to the SI and to stimulate understanding of the concept of uncertainty and assignment of uncertainty statements to measurements. CCQM working groups develop and execute international comparisons to establish the technical basis for the mutual recognition of measurement capabilities. In 2003, IRMM, the metrology institute of the European Commission, launched CCQM pilot study 39 on the measurement of As, Se, Pb, Hg and CH3Hg in tuna. The aims were to strengthen the comparability of measurements EU member states are obliged to make under EC regulation 466/2001 (monitoring of contaminants in food) on the total element contents, and to evaluate the comparability of CH3Hg measurement with new measurement techniques. At the CCQM level, it is necessary to produce measurements for all analytes through processes with established traceability to the SI and with uncertainty statements. The IRMM contribution to CCQM-P39 for the determination of the tuna's CH3Hg amount content was based on species specific isotope dilution mass spectrometry applied as a primary method of measurement. IRMM-670, a newly developed 202Hg enriched CH3Hg isotopic reference material, was blended to the tuna sample, from which Hg species were extracted and derivatised to non-polar forms. Gas chromatography inductively coupled plasma mass spectrometry, GC-ICP-MS, was used for Hg species separation and detection of the n(200Hg)/n(202Hg) ratio in the CH3Hg of the blended material. The SI-traceable CH3Hg amount content was then obtained through comparison using an IDMS equation with the IRMM-670 reference CH3Hg amount content (including the isotopic compositions of natural Hg recommended by IUPAC, and certified for CH3Hg in IRMM-670). IRMM-639, a natural-like Hg

  19. The use of Pb, Sr, and Hg isotopes in Great Lakes precipitation as a tool for pollution source attribution

    International Nuclear Information System (INIS)

    The anthropogenic emission and subsequent deposition of heavy metals including mercury (Hg) and lead (Pb) present human health and environmental concerns. Although it is known that local and regional sources of these metals contribute to deposition in the Great Lakes region, it is difficult to trace emissions from point sources to impacted sites. Recent studies suggest that metal isotope ratios may be useful for distinguishing between and tracing source emissions. We measured Pb, strontium (Sr), and Hg isotope ratios in daily precipitation samples that were collected at seven sites across the Great Lakes region between 2003 and 2007. Lead isotope ratios (207Pb/206Pb = 0.8062 to 0.8554) suggest that Pb deposition was influenced by coal combustion and processing of Mississippi Valley-Type Pb ore deposits. Regional differences in Sr isotope ratios (87Sr/86Sr = 0.70859 to 0.71155) are likely related to coal fly ash and soil dust. Mercury isotope ratios (δ202Hg = − 1.13 to 0.13‰) also varied among the sites, likely due to regional differences in coal isotopic composition, and fractionation occurring within industrial facilities and in the atmosphere. These data represent the first combined characterization of Pb, Sr, and Hg isotope ratios in precipitation collected across the Great Lakes region. We demonstrate the utility of multiple metal isotope ratios in parallel with traditional trace element multivariate statistical modeling to enable more complete pollution source attribution. - Highlights: • We measured Pb, Sr, and Hg isotopes in precipitation from the Great Lakes region. • Pb isotopes suggest that deposition was impacted by coal combustion and metal production. • Sr isotope ratios vary regionally, likely due to soil dust and coal fly ash. • Hg isotopes vary due to fractionation occurring within facilities and the atmosphere. • Isotope results support conclusions of previous trace element receptor modeling

  20. Comparison of total Hg results in sediment samples from Rio Grande reservoir determine by NAA and CV AAS

    Energy Technology Data Exchange (ETDEWEB)

    Franklin, Robson L., E-mail: robsonf@cetesbnet.sp.gov.br [Centro Tecnologico de Saneamento Basico (ELAI/CETESB), SP, Sao Paulo (Brazil). Laboratorio de Quimica Inorganica; Bevilacqua, Jose Eduardo [Centro Tecnologico de Saneamento Basico (CETESB), SP, Sao Paulo (Brazil). UNIFIEO - Centro Universitario FIEO; Favaro, Deborah I.T., E-mail: defavaro@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Laboratorio de Analise por Ativacao Neutronica (LAN/CRPq)

    2011-07-01

    The Rio Grande reservoir is located in the Metropolitan area of Sao Paulo and it is used for recreation purposes and as source water for drinking water production. During the last decades has been detected mercury contamination in the sediments of this reservoir, mainly in the eastern part, near the main affluent of the reservoir, in the Rio Grande da Serra and Ribeirao Pires counties. In the present study bottom sediment samples were collected in four different sites into four sampling campaigns during the period of September 2008 to January 2010. The samples were dried at room temperature, ground and passed through a 2 mm sieve. Total Hg determination in the sediment samples was carried out by two different analytical techniques: neutron activation analysis (NAA) and cold vapor atomic absorption spectrometry (CV AAS). The methodology validation, in terms of precision and accuracy, was performed by reference materials, and presented a recovery of 83 to 108%. The total Hg results obtained by both analytical techniques ranged from 3 to 71 mg kg-1 and were considered similar by statistical analysis, even though NAA technique furnishes the total concentration while CV AAS using the 3015 digestion procedure characterizes only the bioavailable Hg. These results confirm that both analytical techniques were suitable to detect the Hg concentration levels in the Rio Grande sediments studied. The Hg levels in the sediment of the Rio Grande reservoir confirm the anthropogenic origin for this element in this ecosystem. (author)

  1. Radiation trapping of the Hg 254 nm resonance line

    Energy Technology Data Exchange (ETDEWEB)

    Herd, M T [Department of Physics, University of Wisconsin, Madison, WI 53705 (United States); Lawler, J E [Department of Physics, University of Wisconsin, Madison, WI 53705 (United States); Menningen, K L [Department of Physics and Astronomy, University of Wisconsin, Stevens Point, WI 54481 (United States)

    2005-09-07

    The decay rate of Hg 6 {sup 3}P{sub 1} atoms, due primarily to the escape of trapped 254 nm resonance radiation, was measured as a function of both Hg and Ar density in cylindrical, sealed fused silica cells. Time-resolved laser-induced fluorescence at 254 nm was used to obtain the decay rates for Hg densities from 5 x 10{sup 13} to 7 x 10{sup 15} cm{sup -3} (22-101 deg. C cold spot temperatures) and Ar densities from 0 to 9.7 x 10{sup 17} cm{sup -3} in a cell of inner radius 1.05 cm. These new experimental data are compared to Monte Carlo results from a highly realistic code for simulating radiation trapping. This code includes Voigt profiles from a combination of Doppler, resonance, buffer gas and radiative line broadening, as well as hyperfine and isotopic structure with proper collisional redistribution. Upper limits on the rate constants for the quenching of Hg 6 {sup 3} P{sub 1} atoms by collisions with ground level Ar and Hg atoms were derived. Additional Monte Carlo simulations covering cell radii from 0.1 to 3.0 cm were performed. A broadly applicable engineering formula is derived from this study, which predicts the Hg 6 {sup 3}P{sub 1} decay rate from 254 nm resonance radiation trapping as a function of Hg and Ar densities and cell radius.

  2. 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.

  3. Photocatalysis of Hg2+ y Cr6+ in waste waters

    International Nuclear Information System (INIS)

    This work was carried out to propose a treatment for the elimination of Hg2+ and Cr6+ ions that are present in wastewaters of the CIA and ISA laboratories. These ions are present in waste waters because in these laboratories analysis of chemical oxygen demand (COD), are performed in which HgSO4 and K2Cr2O7 are used. COD is a parameter very important to evaluate. In this paper water pollution results of chemical reduction of Hg2+ and Cr6+ ions using photo catalysis are reported and the elimination of both ions by using an adsorbent

  4. Summary Abstract: HgTe–CdTe superlattices

    OpenAIRE

    McGill, T. C.; Smith, D L

    1983-01-01

    In their seminal paper on superlattices, Esaki and Tsu indicated that superlattices involving II-VI compounds and their alloys, could be of interest along with superlattices involving Group IV and III-V semiconductors. Independently, Schulman and McGill identified the Hg-Te-CdTe superlattice as an interesting case to study. HgTe and CdTe have the same crystal structure and lattice constrant to 0.3%. CdTe is a conventional zinc blende semiconductor with a band gap of about 1.6 eV; HgTe is a ze...

  5. Hg and Se Speciation in Liver Tissue of Marine Birds

    International Nuclear Information System (INIS)

    X-ray fluorescence microprobe maps of Hg and Se distribution were made on liver tissue slices from marine birds (Cormorants) from Florida's Everglades. The birds bio-concentrate these toxic pollutants that are ingested from their diet of fish. The fluorescence maps show strong localization of Mercury and Selenium into 'hot spots' less than 100 microns in size. XAFS measurements were made on hot spots to demonstrate that the Hg and Se are indeed are chemically bound, supporting the idea that moderate levels of Se may have a protective effect against Hg through its complexation.

  6. Influence of soil chemistry on metal and bioessential element concentrations in nymphal and adult periodical cicadas (Magicicada spp.)

    Science.gov (United States)

    Robinson, G.R., Jr.; Sibrell, P.L.; Boughton, C.J.; Yang, L.H.

    2007-01-01

    Metal and bioessential element concentrations were measured in three species of 17-year periodical cicadas (Magicicada spp.) to determine how cicada tissue chemistry is affected by soil chemistry, measure the bioavailability of metals from both uncontaminated and lead-arsenate-pesticide contaminated soils, and assess the potential risks of observed metal contamination for wildlife. Periodical cicada nymphs feed on root xylem fluids for 13 or 17??years of underground development. The nymphs then emerge synchronously at high densities, before leaving their nymphal keratin exoskeleton and molting into their adult form. Cicadas are an important food source for birds and animals during emergence events, and influence nutrient cycles in woodland ecosystems. Nymphal exoskeletons and whole adult cicadas were sampled in Clarke and Frederick Counties, Virginia and Berkeley and Jefferson Counties, West Virginia during the Brood X emergence in May and June, 2004. Elements, such as Al, Fe, and Pb, are strongly enriched in the nymphal exoskeleton relative to the adult body; Cu and Zn are enriched in bodies. Concentrations of Fe and Pb, when normalized to relatively inert soil constituents such as Al and Ce, are similar in both the molt exoskeleton and their host soil, implying that passive assimilation through prolonged soil contact (adhesion or adsorption) might control these metal concentrations. Normalized concentrations of bioessential elements, such as S, P, K, Ca, Mn, Cu, Zn, and Mo, and chalcophile (sulfur-loving) elements, such as As, Se, and Au, indicate strong enrichment in cicada tissues relative to soil, implying selective absorption and retention by xylem fluids, the cicada nymphs themselves, or both. Element enrichment patterns in cicada tissues are similar to enrichment patterns observed in xylem fluids from tree roots. Chalcophile elements and heavy metals accumulate in keratin-rich tissues and may bind to sulfhydryl groups. Metal concentrations in the nymphal

  7. Accumulation of trace elements in harp seals (Phoca groenlandica) from Pangnirtung in the Baffin Island, Canada.

    Science.gov (United States)

    Agusa, Tetsuro; Nomura, Kumiko; Kunito, Takashi; Anan, Yasumi; Iwata, Hisato; Tanabe, Shinsuke

    2011-01-01

    Nineteen trace elements were determined in liver, muscle, kidney, gonads, and hair of 18 harp seals (Phoca groenlandica) from Pangnirtung in the Baffin Island, Canada. Concentrations of V, Mn, Fe, Cu, Mo, Ag, and Hg in the liver, Co, Cd, and Tl in the kidney, and Ba and Pb in the hair were significantly higher than those in other tissues. Significant positive correlations between Hg concentrations in the hair, and liver, kidney and testis imply usefulness of the hair sample for non-destructive monitoring of Hg in the harp seals. It is suggested that whereas Hg preferentially accumulates in the liver, the accumulation in other tissues is induced at higher hepatic Hg levels. In contrast, Se may not be accumulated in other tissues compared with the liver even at higher hepatic Hg levels because of the presence of excess Se for Hg detoxification in other tissues. PMID:21411109

  8. No magnetic field in the spotted HgMn star mu Leporis

    CERN Document Server

    Kochukhov, O; Piskunov, N; Jeffers, S V; Johns-Krull, C M; Keller, C U; Rodenhuis, M; Snik, F; Stempels, H C; Valenti, J A

    2011-01-01

    Chemically peculiar stars of the mercury-manganese (HgMn) type represent a new class of spotted late-B stars, in which evolving surface chemical inhomogeneities are apparently unrelated to the presence of strong magnetic fields but are produced by some hitherto unknown astrophysical mechanism. The goal of this study is to perform a detailed line profile variability analysis and carry out a sensitive magnetic field search for one of the brightest HgMn stars - mu Lep. We acquired a set of very high-quality intensity and polarization spectra of mu Lep with the HARPSpol polarimeter. These data were analyzed with the multiline technique of least-squares deconvolution in order to extract information on the magnetic field and line profile variability. Our spectra show very weak but definite variability in the lines of Sc, all Fe-peak elements represented in the spectrum of mu Lep, as well as Y, Sr, and Hg. Variability might also be present in the lines of Si and Mg. Anomalous profile shapes of Ti II and Y II lines s...

  9. Study on procedure for determination of Cr, As, Se, Cd, Hg, Pb in some kinds of herb products such as: kind of fungus, philamin... by ICP-MS

    International Nuclear Information System (INIS)

    The determination of Cr, As, Se, Cd, Hg, Pb in herb products such as: kind of fungus, philamin, etc by ICP-MS has been studied. The effects of the parameters of ICP-MS instrument, concentration of nitric acid and high concentration of some elements on the determination of Cr, As, Se, Cd, Hg, Pb by ICP-MS has been concerned. The study and choice the suitable internal standard for the accurate determination of Hg has been sold. The suitable parameters of the microwave, composition and content of the acid mixture for the complete decomposition of the sample have been studied. The recommended procedure has been applied to the determination of Cr, As, Se, Cd, Hg, Pb in the standard samples and real samples. The error of the results is acceptable. (author)

  10. Persistent Hg contamination and occurrence of Hg-methylating transcript (hgcA) downstream of a chlor-alkali plant in the Olt River (Romania).

    Science.gov (United States)

    Bravo, Andrea G; Loizeau, Jean-Luc; Dranguet, Perrine; Makri, Stamatina; Björn, Erik; Ungureanu, Viorel Gh; Slaveykova, Vera I; Cosio, Claudia

    2016-06-01

    Chlor-alkali plants using mercury (Hg) cell technology are acute point sources of Hg pollution in the aquatic environment. While there have been recent efforts to reduce the use of Hg cells, some of the emitted Hg can be transformed to neurotoxic methylmercury (MeHg). Here, we aimed (i) to study the dispersion of Hg in four reservoirs located downstream of a chlor-alkali plant along the Olt River (Romania) and (ii) to track the activity of bacterial functional genes involved in Hg methylation. Total Hg (THg) concentrations in water and sediments decreased successively from the initial reservoir to downstream reservoirs. Suspended fine size particles and seston appeared to be responsible for the transport of THg into downstream reservoirs, while macrophytes reflected the local bioavailability of Hg. The concentration and proportion of MeHg were correlated with THg, but were not correlated with bacterial activity in sediments, while the abundance of hgcA transcript correlated with organic matter and Cl(-) concentration, indicating the importance of Hg bioavailability in sediments for Hg methylation. Our data clearly highlights the importance of considering Hg contamination as a legacy pollutant since there is a high risk of continued Hg accumulation in food webs long after Hg-cell phase out. PMID:26662302

  11. Dynamical evolution of titanium, strontium, and yttrium spots on the surface of the HgMn star HD 11753

    CERN Document Server

    Briquet, M; Gonzalez, J F; Hubrig, S; Hackman, T

    2010-01-01

    Aims. We gathered about 100 high-resolution spectra of three typical HgMn (mercury-manganese) stars, HD 11753, HD 53244, and HD 221507, to search for slowly pulsating B-like pulsations and surface inhomogeneous distribution of various chemical elements. Methods. Classical frequency analysis methods were used to detect line profile variability and to determine the variation period. Doppler imaging reconstruction was performed to obtain abundance maps of chemical elements on the stellar surface. Results. For HD 11753, which is the star with the most pronounced variability, distinct spectral line profile changes were detected for Ti, Sr, Y, Zr, and Hg, whereas for HD 53244 and HD 221507 the most variable line profiles belong to the elements Hg and Y, respectively. We derived rotation periods for all three stars from the variations of radial velocities and equivalent widths of spectral lines belonging to inhomogeneously distributed elements: P_rot (HD 11753)=9.54 d, P_rot (HD 53244)=6.16 d, and P_rot (HD 221507)=...

  12. Measurements of shape co-existence in $^{182,184}$Hg using Coulomb excitation

    CERN Multimedia

    Voulot, D; Paul, E S; Siem, S; Czosnyka, T; Napiorkowski, P J; Iwanicki, J S

    2007-01-01

    We propose to exploit the unique capability of ISOLDE to provide post-accelerated $^{182,184}$Hg ions from the REX facility to enable the lowest states of these nuclei to be Coulomb excited. By measuring the $\\gamma$-ray yields using the MINIBALL array we can measure the transition and diagonal E2 matrix elements for these states. This will give quantitative information about the nature of the shape coexistence in these nuclei and allow the sign of the quadrupole deformation be determined for the first time. We require 24 shifts to fulfill the aims of the experiment.

  13. Analysis by neutron activation in moss samples for the determination of Cr, Se, As and Hg

    International Nuclear Information System (INIS)

    This research work, presents a study of environmental monitoring in the Metropolitan Area of Toluca Valley using as bio-monitors to the mosses (bryophytes) native of different sites, analyzing the concentrations of As, Cr, Hg and Se, present in its structure. The analysis technique used to identify and to quantify to these elements was the Analysis by Neutron Activation, a nuclear analytic technique that allowed determining the concentrations at track level for its great versatility. Likewise the morphological study of the bryophyte Leskea angustata is presented by scanning electron microscopy. (Author)

  14. Direct determination of Cd, Hg in liver and kidney by prompt gamma activation analysis

    International Nuclear Information System (INIS)

    The development of a method for in-vivo measurement of some elemental concentration in organs making use of prompt gamma activation analysis with the filtered neutron beam at the Dalat reactor is being carried out. In this paper we present primary results in research and development of an IVPGNAA facility at the Dalat reactor. Beside the description of experimental set-up, it consists of determination of thermal neutron flux distribution in phantom, and the evaluation of the detection limit and analytical sensitivity for Cd and Hg in the kidney and the liver. Discussions are given to improve the IVPGNAA facility in the future. (author)

  15. DISTRIBUCIJE Hg U ZRAKU TLA I Hg U TLU OKO NAPUŠTENOG RUDNIKA „ZRINSKI“ NA MEDVEDNICI

    OpenAIRE

    Jug, Nataša; Barudžija, Uroš; Durn, Goran

    2008-01-01

    U radu su prikazana terenska i laboratorijska istraživanja, statističke analize i grafički prikazi rezultata određivanja distribucija Hg u zraku tla i Hg u tlu, na području oko napuštenog rudnika „Zrinski“ na Medvednici (tzv. „Rudarski vrt“). Vrijednosti ukupnih koncentracija Hg u zraku tla pokazuju lognormalnu raspodjelu, a njihova prostorna distribucija upućuje na vezu s prisutnom Pb-Ag-Zn mineralizacijom i potvrđuje antropogeno podrijetlo reljefnih neravnina (nakupine jalovine nazvane „pin...

  16. Effects of Hg2+, CH3-Hg+, and Temperature on the Expression of Mercury Resistance Genes in Environmental Bacteria

    OpenAIRE

    Tsai, Yu-Li; Olson, Betty H.

    1990-01-01

    Twenty different bacterial isolates obtained from a mercury-contaminated site in Oak Ridge, Tenn., were grown on plate count agar amended with 25 μg of Hg2+ or 3 μg of CH3-Hg+ (R-Hg+) per ml. The total cellular RNA was extracted from each isolate by an acid-guanidine-thiocyanate-phenol-chloroform method. The transcripts of merA and merB were detected and quantitated by Northern (RNA) hybridization. A qualitative assay of mercuric reductase was used to confirm the enzyme activity. Low temperat...

  17. Horizontal Branch stars as AmFm/HgMn stars

    CERN Document Server

    Michaud, G

    2008-01-01

    Recent observations and models for horizontal branch stars are briefly described and compared to models for AmFm stars. The limitations of those models are emphasized by a comparison to observations and models for HgMn stars.

  18. Interaction of Hg Atom with Bare Si(111) Surface

    Institute of Scientific and Technical Information of China (English)

    LIU Yong-Jun; LIU Ying

    2006-01-01

    To evaluate the interaction between Hg atom and bare Si(111) surface, three types of silicon cluster models of Si4H7, Si7H10 and Si16H20 together with their Hg complexes were studied by using hybrid (U)B3LYP density functional theory method. Optimized geometries and energies for Hg atom on different adsorption sites indicate that: 1) the binding energies at different adsorption sites are small (ranging from ~3 to 8 kJ/mol dependent on the adsorption sites), suggesting a weak interaction between Hg atom and silicon surface; 2) the most favorable adsorption site is the on top (T) site. By analyzing their natural bonding orbitals, the possible reason of this difference is suggested.

  19. Observation of Broadband Ultraviolet Emission From Hg 3 *

    Science.gov (United States)

    Chen, Wenting; Glavin, Thomas; Eden, James; Laboratory for Optical Physics; Engineering Team

    2016-05-01

    A previously-unobserved emission continuum, peaking at ~ 380 nm, has been observed when Hg vapor is photoexcited at 248 nm (KrF laser). Attributed to the mercury trimer, Hg3, this emission continuum has a spectral breadth (FWHM) which increases from ~ 65 nm to ~ 90 nm when the Hg number density rises from ~1016 cm-3 to ~ 2 ×1019 cm-3. Over the same interval in [Hg], the emission decay rate increases only slightly (~ 6 ×103 s-1 to ~ 7 ×103 s-1). Comparisons of the observed spectrum with theory suggest that the observed continuum is the result of transitions between pairs of electronic states having a linear or equilateral triangular configuration.

  20. Quantum Calorimeters Based on HgCdTe Alloys Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA's next generation of x-ray observation missions require x-ray calorimeters with superior energy resolution. Semimetallic HgTe has already proven itself as an...

  1. Long-wavelength infrared photoconductor technology based on epitaxially grown Hg1-xCdxTe

    Science.gov (United States)

    Siliquini, John F.; Fynn, Kevin A.; Musca, Charles A.; Nener, Brett D.; Dell, John M.; Faraone, Lorenzo

    1995-09-01

    The performance of Hg1-xCdxTe long wavelength infrared (LWIR) photoconductors is strongly dependent on the semiconductor surface conditions and contact characteristics. In this paper we review these effects in relation to obtaining an optimum device technology suitable for use in two-dimensional infrared focal plane arrays (IRFPAs) based on the fabrication of high performance LWIR photoconductors on epitaxially grown Hg1-xCdxTe. Although the proposed design can be applied to a variety of epitaxially grown Hg1-xCdxTe material, for optimum performance the starting Hg1-xCdxTe semiconductor consists of epitaxially grown heterostructure layers in which a two-dimensional mosaic of lateral design photoconductors are fabricated. The heterostructure layer provides high performance devices at greatly reduced power dissipation levels, while the unique design allows for the high density integration of photoconductors in a two-dimensional array geometry with high fill factor. The proposed photoconductor array with n+ blocking contacts has been experimentally verified in a 3 X 3 array format with all elements in the array exhibiting background limited infrared photodetector (BLIP) performance at 80 K. Performance issues such as response uniformity, pixel yield, fill factor, crosstalk, power dissipation, detector impedance, array architecture, and maximum array size are discussed in relation to the suitability of the proposed photoconductor structure for use in IRFPA modules. It is found that in many cases the proposed photoconductor technology has the potential to deliver significant advantages, such as higher yield, higher fill factor, better uniformity, less crosstalk, and larger potential array size, in comparison to an IRFPA design based on photovoltaic technology.

  2. Relativistic density functional calculations using two-spinor minimax finite-element method and linear combination of atomic orbitals for ZnO, CdO, HgO, UubO and Cu2, Ag2, Au2, Rg2.

    Science.gov (United States)

    Kullie, O; Zhang, H; Kolb, J; Kolb, D

    2006-12-28

    In previous work the authors have presented a highly accurate two-spinor fully relativistic solution of the two-center Coulomb problem utilizing the finite-element method (FEM) and furthermore developed a relativistic minimax two-spinor linear combination of atomic orbitals (LCAO). In the present paper the authors present Dirac-Fock-Slater (DFS-) density functional calculations for two-atomic molecules up to super heavy systems using the fully nonlinear minimax FEM and the minimax LCAO in its linearized approximation (linear approximation to relativistic minimax). The FEM gives highly accurate benchmark results for the DFS functional. Especially considering molecules with up to super heavy atoms such as UubO and Rg2, the authors found that LCAO fails to give the correct systematic trends. The accurate FEM results shed a new light on the quality of the DFS-density functional. PMID:17199347

  3. Magnetotransport in double quantum well with inverted energy spectrum: HgTe/CdHgTe

    Science.gov (United States)

    Yakunin, M. V.; Suslov, A. V.; Popov, M. R.; Novik, E. G.; Dvoretsky, S. A.; Mikhailov, N. N.

    2016-02-01

    We present an experimental study of the double-quantum-well (DQW) system made of two-dimensional layers with inverted energy band spectrum: HgTe. The magnetotransport reveals a considerably larger overlap of the conduction and valence subbands than in known HgTe single quantum wells (QW), which may be regulated here by an applied gate voltage Vg. This large overlap manifests itself in a much higher critical field Bc separating the range above it with a plain behavior of the Hall magnetoresistance ρx y(B ) , where the quantum peculiarities shift linearly with Vg, and the range below with a complicated behavior. In the latter case, specific structures in ρx y(B ) are formed like a double-N -shaped ρx y(B ) , reentrant sign-alternating quantum Hall effect with transitions into a zero-filling-factor state, etc., which are clearly manifested here due to better magnetic quantization at high fields, as compared to the features seen earlier in a single HgTe QW. The coexisting electrons and holes were found in the whole investigated range of positive and negative Vg as revealed (i) from fits to the low-field N -shaped ρx y(B ) , (ii) from the Fourier analysis of oscillations in ρx x(B ) , and (iii) from a specific behavior of ρx y(B ) at high positive Vg. A peculiar feature here is that the found electron density n remains almost constant in the whole range of investigated Vg while the hole density p drops down from the value a factor of 6 larger than n at extreme negative Vg to almost zero at extreme positive Vg passing through the charge-neutrality point. We show that this difference between n and p stems from an order of magnitude larger density of states for holes in the lateral valence subband maxima than for electrons in the conduction subband minimum. We analyze our observations on the basis of a calculated picture of magnetic levels in a DQW and suggest that their specificity is due to (i) a nonmonotonic course of the valence subband magnetic levels and an

  4. Simultaneous determination of Hg(II) and alkylated Hg, Pb, and Sn species in human body fluids using SPME-GC/MS-MS

    Energy Technology Data Exchange (ETDEWEB)

    Dunemann, L.; Hajimiragha, H.; Begerow, J. [Department of Analytical Chemistry, Medizinisches Inst. fuer Umwelthygiene, Duesseldorf (Germany)

    1999-03-01

    A GC/MS-MS method for the determination of Hg(II) and alkylated Hg, Pb, and Sn species in human urine is described. Separation and identification of the metal species are performed by capillary gas chromatography coupled with an ion-trap mass spectrometer with electron impact ionization in the tandem-MS mode. For sample preparation a very promising technique was applied that is based on a derivatization with sodium tetraethylborate followed by headspace solid phase microextraction (SPME). Operation of the used ion trap in the tandem-MS mode yields in improved detection limits because of a signal-to-noise ratio that is at least one order of magnitude better than in the MS mode. The detection limits in real matrices like urine are between 7 and 22 ng/L for all species investigated. Urinary levels of inorganic Hg in non-occupationally exposed persons with and without dental amalgam were found to be between 0.1 and 1.4 {mu}g/L. A reference material (``ClinRep, Level I``) was used for quality assurance. Compared to the coupling of GC with ICP-MS (``inorganic`` MS), the advantage of the proposed method using an ``organic`` MS is that (i) the species can be directly identified via their precursor and daughter ions and (ii) analysis can be performed with a commercially available hyphenated technique at moderate costs and needs no lab-made interfacing. Moreover, it offers a real multi-element/multi-species capability with low detection limits and a minimum of sample preparation. (orig.) With 1 fig., 1 tab., 9 refs.

  5. Thermoelectric Properties of Cu2HgSnSe4-Cu2HgSnTe4 Solid Solution

    Czech Academy of Sciences Publication Activity Database

    Navrátil, Jiří; Kucek, V.; Plecháček, T.; Černošková, E.; Laufek, František; Drašar, Č.; Knotek, P.

    2014-01-01

    Roč. 43, č. 10 (2014), s. 3719-3725. ISSN 0361-5235 R&D Projects: GA ČR GA13-33056S Institutional support: RVO:61389013 ; RVO:68378271 Keywords : quaternary diamond-like compounds * Cu2HgSnSe4 * Cu2HgSnTe4 Subject RIV: CA - Inorganic Chemistry Impact factor: 1.798, year: 2014

  6. Earthworm casts as a sampling medium – a case study from highly contaminated Hg roasting site Pšenk (Idrija area, Slovenia

    Directory of Open Access Journals (Sweden)

    Tamara Teršič

    2013-12-01

    Full Text Available In this study an interesting sampling medium - earthworm casts was examined in a highly Hg contaminated area. Enrichment factor (EF has been applied to assess elevated concentrations of analyzed elements in earthworm casts and to determine elevated concentrations of these elements in soils and casts with regard to European average concentrations in topsoil. In a previous study (Teršič & Gosar, 2012 it was shown that Hg contents and dispersion in casts from studied roasting site are comparable to those in soil, which indicates that soil contamination is substantially reflected in contamination of earthworm casts. Therefore the comparison between elemental concentrations in earthworm casts and soil was investigated with the intention to assess the reflection of possible soil contamination in casts. Besides Hg contamination, elevated concentrations of As, Ca, Cd, Mo, Pb and U were also determined in earthworm casts. The calculated EFs show moderate enrichment of casts with Ca, Sr and P and minimal enrichment with Mg, Zn and Cu. Cast, SOM (surface organic matter rich soil layer and soil enrichments with regard to the European averages show extreme enrichment of all studied media with Hg, followed by significant enrichment with Mo and Cd and moderate enrichment with As. Spatial distributions of analyzed elements in casts mostly show similar pattern as in soil, however, because of the different nature of different earthworm species and specific properties of different elements, the data about cast contamination can only serve as an approximate prediction about the dispersion and distribution of contaminant in soil.

  7. Electronic properties of liquid Hg-In alloys : Ab-initio molecular dynamics study

    Science.gov (United States)

    Sharma, Nalini; Thakur, Anil; Ahluwalia, P. K.

    2016-05-01

    Ab-initio molecular dynamics simulations are performed to study the structural properties of liquid Hg-In alloys. The interatomic interactions are described by ab-initio pseudopotentials given by Troullier and Martins. Three liquid Hg-In alloys (Hg10In90, Hg30In70,. Hg50In50, Hg70In30, and Hg90Pb10) at 299 K are considered. The calculated results for liquid Hg (l-Hg) and lead (l-In) are also drawn. Along with the calculated results of considered five liquid alloys of Hg-In alloy. The results obtained from electronic properties namely total density of state and partial density of states help to find the local arrangement of Hg and In atoms and the presence of liquid state in the considered five alloys.

  8. Simulation and evaluation of elemental mercury concentration increase in flue gas across a wet scrubber.

    Science.gov (United States)

    Chang, John C S; Ghorishi, S Behrooz

    2003-12-15

    Experimental data from a laboratory-scale wet scrubber simulator confirmed that oxidized mercury, Hg2+, can be reduced by aqueous S(IV) (sulfite and/or bisulfite) species and results in elemental mercury (HgO) emissions under typical wet FGD scrubber conditions. The S(IV)-induced Hg2+ reduction and Hg0 emission mechanism can be described by a model which assumes that only a fraction of the Hg2+ can be reduced, and the rate-controlling step of the overall process is a first-order reaction involving the Hg-S(IV) complexes. Experimental data and model simulations predict that the Hg2+ in the flue gas can cause rapid increase of Hg0 concentration in the flue gas across a FGD scrubber. Forced oxidation can enhance Hg2+ reduction and Hg0 emission by decreasing the S(IV) concentration in the scrubbing liquor. The model predictions also indicate that flue gas Hg0 increase across a wet FGD scrubber can be reduced by decreasing the pH, increasing S(IV) concentration, and lowering the temperature. PMID:14717192

  9. Two-dimensional topological insulators with tunable band gaps: Single-layer HgTe and HgSe.

    Science.gov (United States)

    Li, Jin; He, Chaoyu; Meng, Lijun; Xiao, Huaping; Tang, Chao; Wei, Xiaolin; Kim, Jinwoong; Kioussis, Nicholas; Stocks, G Malcolm; Zhong, Jianxin

    2015-01-01

    Two-dimensional (2D) topological insulators (TIs) with large band gaps are of great importance for the future applications of quantum spin Hall (QSH) effect. Employing ab initio electronic calculations we propose a novel type of 2D topological insulators, the monolayer (ML) low-buckled (LB) mercury telluride (HgTe) and mercury selenide (HgSe), with tunable band gap. We demonstrate that LB HgTe (HgSe) monolayers undergo a trivial insulator to topological insulator transition under in-plane tensile strain of 2.6% (3.1%) due to the combination of the strain and the spin orbital coupling (SOC) effects. Furthermore, the band gaps can be tuned up to large values (0.2 eV for HgTe and 0.05 eV for HgSe) by tensile strain, which far exceed those of current experimentally realized 2D quantum spin Hall insulators. Our results suggest a new type of material suitable for practical applications of 2D TI at room-temperature. PMID:26365502

  10. Immobilization of Hg(II) by coprecipitation in sulfate-cement systems.

    Science.gov (United States)

    Serrano, Susana; Vlassopoulos, Dimitri; Bessinger, Brad; O'Day, Peggy A

    2012-06-19

    Uptake and molecular speciation of dissolved Hg during formation of Al- or Fe-ettringite-type and high-pH phases were investigated in coprecipitation and sorption experiments of sulfate-cement treatments used for soil and sediment remediation. Ettringite and minor gypsum were identified by XRD as primary phases in Al systems, whereas gypsum and ferrihydrite were the main products in Hg-Fe precipitates. Characterization of Hg-Al solids by bulk Hg EXAFS, electron microprobe, and microfocused-XRF mapping indicated coordination of Hg by Cl ligands, multiple Hg and Cl backscattering atoms, and concentration of Hg as small particles. Thermodynamic predictions agreed with experimental observations for bulk phases, but Hg speciation indicated lack of equilibration with the final solution. Results suggest physical encapsulation of Hg as a polynuclear chloromercury(II) salt in ettringite as the primary immobilization mechanism. In Hg-Fe solids, structural characterization indicated Hg coordination by O atoms only and Fe backscattering atoms that is consistent with inner-sphere complexation of Hg(OH)(2)(0) coprecipitated with ferrihydrite. Precipitation of ferrihydrite removed Hg from solution, but the resulting solid was sufficiently hydrated to allow equilibration of sorbed Hg species with the aqueous solution. Electron microprobe XRF characterization of sorption samples with low Hg concentration reacted with cement and FeSO(4) amendment indicated correlation of Hg and Fe, supporting the interpretation of Hg removal by precipitation of an Fe(III) oxide phase. PMID:22594782

  11. Concentrations of total and dissolved Hg in snow and vapor deposition collected during Atmospheric Mercury Depletion Events (AMDEs) in Barrow, Alaska during the BROMEX campaign

    Science.gov (United States)

    Obrist, D.; Moore, C. W.; Douglas, T. A.; Steffen, A.; Staebler, R. M.; Pearson, C.

    2012-12-01

    During the Bromine, Ozone, and Mercury Experiment (BROMEX) in March and April 2012, we characterized surface snow concentrations of mercury and major ions near Barrow, Alaska, in order to assess effects of Atmospheric Mercury Depletion Events (AMDE) on surface snow chemistry. During AMDEs, gaseous elemental mercury is oxidized to divalent Hg forms which, due to their high deposition velocities, can lead to increased Hg deposition to snow and ice surfaces. Daily collections of surface snow (top 2 cm) analyzed for total Hg (THg) showed average concentrations of 14 ppt at both an Out-On-The-Ice (OOTI) site on Arctic Ocean first year sea ice 2 km from the shore and at a terrestrial site on tussock tundra 5 km inland. Both sites showed similar concentration variability (THg ranging from 3.9 to 29.3 ppt). The OOTI site, however, showed substantially higher percentages of Hg that was in the dissolved phase (DHg; filtered by 0.45 μm filter), averaging 68% versus 27% at the inland site. These differences were unlikely linked to atmospheric Hg dynamics as both sites showed similar concentrations and temporal patterns of gaseous and oxidized atmospheric Hg. A higher DHg fraction may indicate a different behavior of snow on land versus snow on sea ice snow in regards to accumulating, retaining, or re-emitting mercury. Overall, surface snow Hg concentrations at both sites were weakly and inversely correlated with the daily average atmospheric elemental Hg concentration, showing that depletions of atmospheric Hg and their associated formation of divalent Hg may translate into small surface snow Hg enhancements. A snow transect collected between 2 km out on the sea ice and 6 km inland also showed no inherent differences in THg between inland and sites on the sea ice and confirmed the higher DHg fraction in snow on sea ice. To collect vapor phase ice samples from the lower atmosphere- snow surface interface we designed and deployed a novel "cold plate" sampler that allowed for

  12. Trend and characteristics of atmospheric emissions of Hg, As, and Se from coal combustion in China, 1980–2007

    OpenAIRE

    H. Z. Tian; Wang, Y.; Xue, Z G; Cheng, K.; Qu, Y. P.; Chai, F. H; J. M. Hao

    2010-01-01

    Emissions of hazardous trace elements in China are of great concern because of their negative impacts on local air quality as well as on regional environmental health and ecosystem risks. In this paper, the atmospheric emissions of mercury (Hg), arsenic (As), and selenium (Se) from coal combustion in China for the period 1980–2007 are estimated on the basis of coal consumption data and emission factors, which are specified by different categories of combustion facilities, coal types, and the ...

  13. Trend and characteristics of atmospheric emissions of Hg, As, and Se from coal combustion in China, 1980–2007

    OpenAIRE

    H. Z. Tian; Wang, Y.; Xue, Z G; Cheng, K.; Qu, Y. P.; Chai, F. H; J. M. Hao

    2010-01-01

    Emissions of hazardous trace elements in China are of great concern because of their negative impacts on local air quality as well as on regional environmental health and ecosystem risks. In this paper, the atmospheric emissions of mercury (Hg), arsenic (As), and selenium (Se) from coal combustion in China for the period 1980–2007 are estimated on the basis of coal consumption data and emission factors, which are specified by different categories of combustion facilities, co...

  14. Relativistic coupled cluster study of diatomic compounds of Hg, Cn, and Fl

    International Nuclear Information System (INIS)

    The structure and energetics of eight diatomic heavy-atom molecules are presented. These include the species MAu, M2, and MHg, with M standing for the Hg, Cn (element 112), and Fl (element 114) atoms. The infinite-order relativistic 2-component Hamiltonian, known to closely reproduce 4-component results at lower computational cost, is used as framework. High-accuracy treatment of correlation is achieved by using the coupled cluster scheme with single, double, and perturbative triple excitations in large converged basis sets. The calculated interatomic separation and bond energy of Hg2, the only compound with known experimental data, are in good agreement with measurements. The binding of Fl to Au is stronger than that of Cn, predicting stronger adsorption on gold surfaces. The bond in the M2 species is strongest for Fl2, being of chemical nature; weaker bonds appear in Cn2 and Hg2, which are bound by van der Waals interactions, with the former bound more strongly due to the smaller van der Waals radius. The same set of calculations was also performed using the relativistic density functional theory approach, in order to test the performance of the latter for these weakly bound systems with respect to the more accurate coupled cluster calculations. It was found that for the MAu species the B3LYP functional provides better agreement with the coupled cluster results than the B88/P86 functional. However, for the M2 and the MHg molecules, B3LYP tends to underestimate the binding energies

  15. Methionine-pyrene hybrid based fluorescent probe for trace level detection and estimation of Hg(II) in aqueous environmental samples: Experimental and computational studies

    International Nuclear Information System (INIS)

    A new fluorescent, Hg2+ selective chemosensor, 4-methylsulfanyl-2-[(pyren-4-ylmethylene)-amino] butyric acid methyl ester (L, MP) was synthesized by blending methionine with pyrene. It was well characterized by different analytical techniques, viz. 1H NMR, 13C NMR, QTOF mass spectra, elemental analysis, FTIR and UV-vis spectroscopy. The reaction of this ligand with Hg2+ was studied by steady state and time-resolved fluorescence spectroscopy. The Hg2+ complexation process was confirmed by comparing FTIR, UV-vis, thermal, QTOF mass spectra and 1H NMR data of the product with that of the free ligand values. The composition (Hg2+:L = 1:1) of the Hg2+ complex in solution was evaluated by fluorescence titration method. Based on the chelation assisted fluorescence quenching, a highly sensitive spectrofluorometric method was developed for the determination of trace amounts of Hg2+ in water. The ligand had an excitation and emission maxima at 360 nm and 455 nm, respectively. The fluorescence life times of the ligand and its Hg2+ complex were 1.54 ns and 0.72 ns respectively. The binding constant of the ligand, L with Hg2+ was calculated using Benesi-Hildebrand equation and was found to be 7.5630 x 104. The linear range of the method was from 0 to 16 μg L-1 with a detection limit of 0.056 μg L-1 for Hg2+. The quantum yields of the ligand and its Hg2+ complex were found to be 0.1206 and 0.0757 respectively. Both the ligand and its Hg2+ complex have been studied computationally (Ab-initio, Hartree Fock method) to get their optimized structure and other related physical parameters, including bond lengths, bond angles, dipole moments, orbital interactions etc. The binding sites of the ligand to the Hg2+ ion as obtained from the theoretical calculations were well supported by 1H NMR titration. The interference of foreign ions was negligible. This method has been successfully applied to the determination of mercury(II) in industrial waste water.

  16. Thermal cycling reliability of indirect hybrid HgCdTe infrared detectors

    Science.gov (United States)

    Chen, Xing; He, Kai; Wang, Jian-xin; Zhang, Qin-yao

    2013-09-01

    Thermal cycling reliability is one of the most important issues whether the HgCdTe infrared focal plane array detectors can be applied to both military and civil fields. In this paper, a 3D finite element model for indirect hybrid HgCdTe infrared detectors is established. The thermal stress distribution and thermally induced warpage of the detector assembly as a function of the distance between the detector chip and Si-ROIC, the thickness and the materials properties of electrical lead board in cryogenic temperature are analyzed. The results show that all these parameters have influences on the thermal stress distribution and warpage of the detector assembly, especially the coefficient of thermal expansion(CTE) of electrical lead board. The thermal stress and warpage in the assembly can be avoided or minimized by choosing the appropriate electrical lead board. Additionally, the warpage of some indirect hybrid detectors assembly samples is measured in experiment. The experimental results are in good agreement with the simulation results, which verifies that the results are calculated by finite element method are reasonable.

  17. Indication for a volatile element 114

    International Nuclear Information System (INIS)

    Recently, the chemical investigation of element 112 revealed a highly volatile, noble metallic behaviour, as expected for the last group 12 member of the periodic table. The observed volatility and chemical inertness were ascribed to the growing influence of relativistic effects on the chemical properties of the heaviest elements with increasing nuclear charge. Here, we report for the first time on gas phase chemical experiments aiming at a determination of element 114 properties. This element was investigated using its isotopes 287114 and 288114 produced in the nuclear fusion reactions of 48Ca with 242Pu and 244Pu, respectively. Identification of three atoms of element 114 in thermochromatography experiments and their deposition pattern on a gold surface indicates that this element is at least as volatile as simultaneously investigated elements Hg, At, and element 112. This behaviour is rather unexpected for a typical metal of group 14. (orig.)

  18. Mercury (Hg) burden in children: The impact of dental amalgam

    Energy Technology Data Exchange (ETDEWEB)

    Al-Saleh, Iman, E-mail: iman@kfshrc.edu.sa [Biological and Medical Research Department, King Faisal Specialist Hospital and Research Centre, PO Box: 3354, Riyadh 11211 (Saudi Arabia); Al-Sedairi, Al anoud [Department of Zoology, College of Science, King Saud University, PO Box: 24452, Riyadh 11495 (Saudi Arabia)

    2011-07-15

    The risks and benefits of using mercury (Hg) in dental amalgam have long been debated. This study was designed to estimate Hg body burden and its association with dental amalgam fillings in 182 children (ages: 5-15 years) living in Taif City. Hg was measured in urine (UHg), hair (HHg) and toenails (NHg) by the Atomic Absorption Spectrophotometer with Vapor Generator Accessory system. Urinary Hg levels were calculated as both micrograms per gram creatinine ({mu}g/g creatinine) and micrograms per liter ({mu}g/L). We found that children with amalgam fillings (N = 106) had significantly higher UHg-C levels than children without (N = 76), with means of 3.763 {mu}g/g creatinine versus 3.457 {mu}g/g creatinine, respectively (P = 0.019). The results were similar for UHg (P = 0.01). A similar pattern was also seen for HHg, with means of 0.614 {mu}g/g (N = 97) for children with amalgam versus 0.242 {mu}g/g (N = 74) for those without amalgam fillings (P = 0). Although the mean NHg was higher in children without amalgam (0.222 {mu}g/g, N = 61) versus those with (0.163 {mu}g/g, N = 101), the relationship was not significant (P = 0.069). After adjusting for many confounders, the multiple logistic regression model revealed that the levels of UHg-C and HHg were 2.047 and 5.396 times higher, respectively, in children with dental amalgam compared to those without (P < 0.01). In contrast, a significant inverse relationship was seen between NHg levels and dental amalgam fillings (P = 0.003). Despite the controversy surrounding the health impact of dental amalgam, this study showed some evidence that amalgam-associated Hg exposure might be related with symptoms of oral health, such as aphthous ulcer, white patches, and a burning-mouth sensation. Further studies are needed to reproduce these findings. The present study showed that significant numbers of children with or without amalgam had Hg levels exceeding the acceptable reference limits. The detrimental neurobehavioral and

  19. Mercury (Hg) burden in children: The impact of dental amalgam

    International Nuclear Information System (INIS)

    The risks and benefits of using mercury (Hg) in dental amalgam have long been debated. This study was designed to estimate Hg body burden and its association with dental amalgam fillings in 182 children (ages: 5-15 years) living in Taif City. Hg was measured in urine (UHg), hair (HHg) and toenails (NHg) by the Atomic Absorption Spectrophotometer with Vapor Generator Accessory system. Urinary Hg levels were calculated as both micrograms per gram creatinine (μg/g creatinine) and micrograms per liter (μg/L). We found that children with amalgam fillings (N = 106) had significantly higher UHg-C levels than children without (N = 76), with means of 3.763 μg/g creatinine versus 3.457 μg/g creatinine, respectively (P = 0.019). The results were similar for UHg (P = 0.01). A similar pattern was also seen for HHg, with means of 0.614 μg/g (N = 97) for children with amalgam versus 0.242 μg/g (N = 74) for those without amalgam fillings (P = 0). Although the mean NHg was higher in children without amalgam (0.222 μg/g, N = 61) versus those with (0.163 μg/g, N = 101), the relationship was not significant (P = 0.069). After adjusting for many confounders, the multiple logistic regression model revealed that the levels of UHg-C and HHg were 2.047 and 5.396 times higher, respectively, in children with dental amalgam compared to those without (P < 0.01). In contrast, a significant inverse relationship was seen between NHg levels and dental amalgam fillings (P = 0.003). Despite the controversy surrounding the health impact of dental amalgam, this study showed some evidence that amalgam-associated Hg exposure might be related with symptoms of oral health, such as aphthous ulcer, white patches, and a burning-mouth sensation. Further studies are needed to reproduce these findings. The present study showed that significant numbers of children with or without amalgam had Hg levels exceeding the acceptable reference limits. The detrimental neurobehavioral and/or nephrotoxic effects of

  20. Overcoming phytoremediation limitations. A case study of Hg contaminated soil

    Science.gov (United States)

    Barbafieri, Meri

    2013-04-01

    Phytoremediation is a broad term that comprises several technologies to clean up water and soil. Despite the numerous articles appearing in scientific journals, very few field applications of phytoextraction have been successfully realized. The research here reported on Phytoextraction, the use the plant to "extract" metals from contaminated soil, is focused on implementations to overcome two main drawbacks: the survival of plants in unfavorable environmental conditions (contaminant toxicity, low fertility, etc.) and the often lengthy time it takes to reduce contaminants to the requested level. Moreover, to overcome the imbalance between the technology's potential and its drawbacks, there is growing interest in the use of plants to reduce only the fraction that is the most hazardous to the environment and human health, that is to target the bioavailable fractions of metals in soil. Bioavailable Contaminant Stripping (BCS) would be a remediation approach focused to remove the bioavailable metal fractions. BCS have been used in a mercury contaminated soil from Italian industrial site. Bioavailable fractions were determined by sequential extraction with H2O and NH4Cl.Combined treatments of plant hormone and thioligand to strength Hg uptake by crop plants (Brassica juncea and Helianthus annuus) were tested. Plant biomass, evapotranspiration, Hg uptake and distribution following treatments were compared. Results indicate the plant hormone, cytokinine (CK) foliar treatment, increased evapotranspiration rate in both tested plants. The Hg uptake and translocation in both tested plants increased with simultaneous addition of CK and TS treatments. B. juncea was the most effective in Hg uptake. Application of CK to plants grown in TS-treated soil lead to an increase in Hg concentration of 232% in shoots and 39% in roots with respect to control. While H. annuus gave a better response in plant biomass production, the application of CK to plants grown in TS-treated soil lead to

  1. Thermal study of the solid-state reactions on Pt-15%Rh/Hg system

    International Nuclear Information System (INIS)

    Highlights: • We coated Pt-15%Rh foil electrochemically with Hg. • The TG curve of Pt-15%Rh/Hg foil shows four distinct mass loss steps. • At the end of the first mass loss step only bulk Hg is removed. • In the second mass loss step only PtHg4, characterized by XRD, is decomposed. • In the third and in the fourth mass loss step the PtHg2 and RhHg2 are decomposed and Hg is removed from a solid solution of Pt-15%Rh(Hg). - Abstract: Thermogravimetry (TG), energy dispersive X-ray microanalysis (EDX), scanning electron microscopy (SEM), mapping surface and X-ray diffraction (XRD) were used for the study of solid-state reaction on Pt-15%Rh with electrodeposited mercury. The results suggest when heated the mercury film react with the Pt-15%Rh alloy to form intermetallics having different thermal stabilities indicated by three mass loss steps. The first mass loss step occurs between room temperature and 184 °C only the bulk Hg is removed and PtHg4, PtHg2 and RhHg2 were characterized by XRD. The second step, between 184 and 271 °C, was attributed to PtHg4 decomposition with formation of PtHg2 stabilized by RhHg2. The third step, between 271 and 340 °C, was attributed to decomposition of a solid-solution of PtHg2/RhHg2. The fourth step, between 340 and 600 °C, was ascribed to: (1) a thermal decomposition of PtHg2, formed by a PtHg eutectoid reaction (∼340 °C) on the surface and (2) Hg removal from a solid solution of Pt-15%Rh(Hg)

  2. Are there tangled magnetic fields on HgMn stars?

    CERN Document Server

    Kochukhov, O; Piskunov, N; Jeffers, S V; Johns-Krull, C M; Keller, C U; Rodenhuis, M; Snik, F; Stempels, H C; Valenti, J A

    2013-01-01

    Several recent spectrophotometric studies failed to detect significant global magnetic fields in late-B HgMn chemically peculiar stars, but some investigations have suggested the presence of strong unstructured or tangled fields in these objects. We used detailed spectrum synthesis analysis to search for evidence of tangled magnetic fields in high-quality observed spectra of 8 slowly rotating HgMn stars and one normal late-B star. We also evaluated recent sporadic detections of weak longitudinal magnetic fields in HgMn stars based on the moment technique. Our analysis of the Zeeman broadening of magnetically sensitive spectral lines reveals no evidence of tangled magnetic fields in any of the studied HgMn or normal stars. We infer upper limits of 200-700 G for the mean magnetic field modulus -- much smaller than the field strengths implied by studies based on differential magnetic line intensification and quadratic field diagnostics. The new HARPSpol longitudinal field measurements for the extreme HgMn star H...

  3. 40 CFR 60.4154 - Compliance with Hg budget emissions limitation.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Compliance with Hg budget emissions... Times for Coal-Fired Electric Steam Generating Units Hg Allowance Tracking System § 60.4154 Compliance with Hg budget emissions limitation. (a) Allowance transfer deadline. The Hg allowances are...

  4. 40 CFR 75.38 - Standard missing data procedures for Hg CEMS.

    Science.gov (United States)

    2010-07-01

    ... Hg CEMS. 75.38 Section 75.38 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Standard missing data procedures for Hg CEMS. (a) Once 720 quality assured monitor operating hours of Hg... substitute data for Hg concentration in accordance with the procedures in ( 75.33(b)(1) through...

  5. 40 CFR 60.4121 - Submission of Hg budget permit applications.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Submission of Hg budget permit... Times for Coal-Fired Electric Steam Generating Units Permits § 60.4121 Submission of Hg budget permit applications. (a) Duty to apply. The Hg designated representative of any Hg Budget source required to have...

  6. 40 CFR 60.4110 - Authorization and Responsibilities of Hg designated representative.

    Science.gov (United States)

    2010-07-01

    ... Hg designated representative. 60.4110 Section 60.4110 Protection of Environment ENVIRONMENTAL... Emission Guidelines and Compliance Times for Coal-Fired Electric Steam Generating Units Hg Designated Representative for Hg Budget Sources § 60.4110 Authorization and Responsibilities of Hg designated...

  7. Vertical profile measurements of soil air suggest immobilization of gaseous elemental mercury in mineral soil.

    Science.gov (United States)

    Obrist, Daniel; Pokharel, Ashok K; Moore, Christopher

    2014-02-18

    Evasion of gaseous elemental Hg (Hg(0)g) from soil surfaces is an important source of atmospheric Hg, but the volatility and solid-gas phase partitioning of Hg(0) within soils is poorly understood. We developed a novel system to continuously measure Hg(0)g concentrations in soil pores at multiple depths and locations, and present a total of 297 days of measurements spanning 14 months in two forests in the Sierra Nevada mountains, California, U.S. Temporal patterns showed consistent pore Hg(0)g concentrations below levels measured in the atmosphere (termed Hg(0)g immobilization), ranging from 66 to 94% below atmospheric concentrations throughout multiple seasons. The lowest pore Hg(0)g concentrations were observed in the deepest soil layers (40 cm), but significant immobilization was already present in the top 7 cm. In the absence of sinks or sources, pore Hg(0)g levels would be in equilibrium with atmospheric concentrations due to the porous nature of the soil matrix and gas diffusion. Therefore, we explain decreases in pore Hg(0)g in mineral soils below atmospheric concentrations--or below levels found in upper soils as observed in previous studies--with the presence of an Hg(0)g sink in mineral soils possibly related to Hg(0)g oxidation or other processes such as sorption or dissolution in soil water. Surface chamber measurements showing daytime Hg(0)g emissions and nighttime Hg(0)g deposition indicate that near-surface layers likely dominate net atmospheric Hg(0)g exchange resulting in typical diurnal cycles due to photochemcial reduction at the surface and possibly Hg(0)g evasion from litter layers. In contrast, mineral soils seem to be decoupled from this surface exchange, showing consistent Hg(0)g uptake and downward redistribution--although our calculations indicate these fluxes to be minor compared to other mass fluxes. A major implication is that once Hg is incorporated into mineral soils, it may be unlikely subjected to renewed Hg(0)g re-emission from

  8. Interpretation of the vacancy-ordering controlled growth morphology of Hg{sub 5}In{sub 2}Te{sub 8} precipitates in Hg{sub 3}In{sub 2}Te{sub 6} single crystals by TEM observation and crystallographic calculation

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Jie [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, 127 Youyi Road, Xi’an (China); School of Chemical and Biomolecular Engineering, The University of Sydney, NSW 2006 (Australia); Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006 (Australia); Fu, Li, E-mail: fuli@nwpu.edu.cn [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, 127 Youyi Road, Xi’an (China); Liu, Hongwei [Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006 (Australia); Ringer, S.P. [Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW 2006 (Australia); School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, NSW 2006 (Australia); Liu, Zongwen, E-mail: zongwen.liu@sydney.edu.au [School of Chemical and Biomolecular Engineering, The University of Sydney, NSW 2006 (Australia)

    2015-02-15

    Graphical abstract: The growth morphology and detailed crystallography of Hg{sub 5}In{sub 2}Te{sub 8} precipitates in Hg{sub 3}In{sub 2}Te{sub 6} matrix to has been interpreted by means of transmission electron microscopy and invariant element deformation model. Three crystallographic equivalent variants of Hg{sub 5}In{sub 2}Te{sub 8} precipitates in Hg{sub 3}In{sub 2}Te{sub 6} matrix were found to have different growth directions and habit planes. Such growth morphology is fully attributed to the lattice shrinkage induced by vacancy ordering under high temperature in Hg{sub 5}In{sub 2}Te{sub 8}. Through near coincident site lattice and invariant strain calculation, the morphology and crystallographic features of the precipitate has been successfully interpreted. - Highlights: • The growth morphology of Hg{sub 5}In{sub 2}Te{sub 8} precipitates in Hg{sub 3}In{sub 2}Te{sub 6} was observed by TEM. • Near-CSL calculation show 0.7577% lattice shrinkage of Hg{sub 5}In{sub 2}Te{sub 8} at high temperature. • All the involved factors have inverse relationship with the move speed of interface. • The calculated crystallography features of Hg{sub 5}In{sub 2}Te{sub 8} agree well with the TEM results. - Abstract: Generally, the crystal growth morphology in liquid or vapor was controlled by chemical potential, while that in solid solute was restricted by 3D strain matching between matrix and secondary phase. It is already known that the growth and evolution of the morphology of secondary phase during the solid phase transformation are highly determined by the variation of interface energy induced by lattice mismatch. In this work, the growth morphology and crystallography of Hg{sub 5}In{sub 2}Te{sub 8} precipitates in Hg{sub 3}In{sub 2}Te{sub 6} matrix were investigated by means of transmission electron microscopy (TEM). It was found that the growth of Hg{sub 5}In{sub 2}Te{sub 8} precipitates displayed an unusual growth morphology which contain three crystallographically

  9. Interaction in ternary HgBr2-BaBr2-CsBr system

    International Nuclear Information System (INIS)

    Series of polythermal sections in ternary HgBr2-BaBr2-CsBr system are investigated by the methods of physicochemical analysis. In double systems restricting ternary HgBr2-BaBr2-CsBr system formation of CsHg2Br5, CsHgBr3, Cs2HgBr4, CsBa2Br4 and CsBa2Br5 compounds is detected. Projection of liquidus surface of ternary HgBr2-BaBr2-CsBr system on triangle of compositions is plotted. This projection consists of eight fields of the primary crystallization of phases: HgBr2, BaBr2, CsBr, CsHgBr5, CsHgBr3, Cs2HgBr4, Cs2BaBr4 and CsBa2Br5. Coordinates of nonvariant points are determined

  10. Synthesis and characterization of complexes of monoacetylferrocene-4-phenyl thiosemicarbazone with UO22+, Hg2+, Ni2+ or Zn2+ ions

    International Nuclear Information System (INIS)

    Complexes have been synthesized with monoacetylferrocene-4-phenyl thiosemicarbazone (L) combining with UO22+, Hg2+, Ni2+ or Zn2+ ions and characterized through elemental analysis, IR spectrum, UV spectrum and 1HNMR spectrum. The thermal stability and molar conductance have been studied. It shows that L coordinates to the metal ion in a Keto form and is a bidentate ligand

  11. Determination of As, Cd, Cr, Cu, Hg, Sb and Se concentrations by radiochemical neutron activation analysis in different Brazilian regional diets

    International Nuclear Information System (INIS)

    Radiochemical separation procedures developed for the determination of seven elements: As, Cd, Cr, Cu, Hg, Sb and Se in different Brazilian regional diets are described. In the case of the elements As, Hg, Sb and Se, the procedure was based on retention in inorganic exchanger TFO (tin dioxide) and determination of Hg by extraction with Ni(DDC)2. For determination of Cd, Cr, Cu and Se the procedure chosen was based on retention in inorganic exchanger HMD (hydrated manganese dioxide) and extraction of Cu and Cd as diethyldithiocarbamate compounds. The accuracy and precision of the methods studied were tested by means of analyses of different reference materials-Due to the lack of data on trace element levels in Brazilian foodstuffs and diets, these methods were applied to determination of these elements in different Brazilian regional diets. These s were supplied by the Food and Experimental Nutrition Department of the Faculty of Pharmaceutical Science, University of Sao Paulo. The daily intake values for these diets are presented for As, Cd, Cr, Cu, Hg, Sb and Se. (author) 21 refs.; 6 tabs

  12. Determination of toxic and essential elements in seafood

    International Nuclear Information System (INIS)

    Indonesia has only a list of the maximum permissible concentration of toxic elements in water stated in a national legislation. Therefore, it is important to study the toxic elements content in fish and shellfish, because these marine organisms are good biological indicators. The interesting elements to be analyzed are toxic elements, i.e. As, Cd, Cr, Hg, Pb, Sb and Se, and essential elements, i.e., Zn and Cu. As, Cr, Hg, Sb, Se and Zn can be determined by Neutron Activation Analysis (NAA), while Cd, Cu and Pb by Atomic Absorption Spectrometry (AAS). The determination of such elements in foodstuff i.e. rice, corn, green pea, wheat, vegetables, fruits, tea and coffee have been done previously. The major purpose of this work is to know whether the concentration of toxic elements in marine organisms is approaching or exceeding the maximum permissible concentration as stated by International legislation. 7 refs, 5 tabs

  13. Tinjauan terhadap tailing mengandung unsur pencemar Arsen (As), Merkuri (Hg), Timbal (Pb), dan Kadmium (Cd) dari sisa pengolahan bijih logam

    OpenAIRE

    Danny Zulkifli Herman

    2014-01-01

    http://dx.doi.org/10.17014/ijog.vol1no1.20064aWhen tailing of a mining activity is discharged into either landscape or river body, the pollutan element wastes are possible to disperse within those areas and may cause pollution on environment. The environment pollution hazards of arsenic (As), mercury (Hg), lead (Pb) and cadmium (Cd) probably occurred if tailing with the content of those elements is not handled properly. Particularly in the tropical regions, higher rates of chemical weathering...

  14. Highly excited Δ3 I=1 structures in 193Hg

    International Nuclear Information System (INIS)

    Highly excited states in the nucleus 193Hg have been investigated by in-beam γ-ray spectroscopic techniques using the EUROGAM array. The reaction 150Nd(48Ca,5n) at a beam energy of 213 MeV was used to populate states of 193Hg. The level scheme has been considerably extended (up to 10.7 MeV) and enriched from earlier studies. Two new structures of competing dipole and quadrupole transitions were observed. Experimental B(M1)/B(E2) ratios were determined for the two structures and compared with theoretical estimates. They were also compared with similar structures in the neighbouring Hg and Pb nuclei. (author)

  15. Effect of doping on electronic properties of HgSe

    Science.gov (United States)

    Nag, Abhinav; Sastri, O. S. K. S.; Kumar, Jagdish

    2016-05-01

    First principle study of electronic properties of pure and doped HgSe have been performed using all electron Full Potential Linearized Augmented Plane Wave (FP-LAPW) method using ELK code. The electronic exchange and co-relations are considered using Generalized Gradient Approach (GGA). Lattice parameter, Density of States (DOS) and Band structure calculations have been performed. The total energy curve (Energy vs Lattice parameter), DOS and band structure calculations are in good agreement with the experimental values and those obtained using other DFT codes. The doped material is studied within the Virtual Crystal Approximation (VCA) with doping levels of 10% to 25% of electrons (hole) per unit cell. Results predict zero band gap in undopedHgSe and bands meet at Fermi level near the symmetry point D. For doped HgSe, we found that by electron (hole) doping, the point where conduction and valence bands meet can be shifted below (above) the fermi level.

  16. Transuranium elements

    International Nuclear Information System (INIS)

    In this paper, the authors introduce this volume of historical and research papers on the transuranium elements by reviewing the period of discovery of elements 93 and beyond. Then the authors highlight the research achievements that focus on the unique properties of the 5f elements. Finally, the authors outline the technology and applications of transuranium elements and their radiobiology

  17. Hg+ ion density in low-pressure Ar-Hg discharge plasma used for liquid crystal display back-lighting

    International Nuclear Information System (INIS)

    The positive column of a low-pressure Ar-Hg discharge has been applied as a fluorescent light source for illumination. Many studies on the diagnostics and fundamental mechanisms have been carried out on both the classical fluorescent lamp (d=36 mm) and the compact fluorescent lamp (d=12 mm). On the other hand, a lamp of extremely narrow diameter (usually below 6 mm) has been recently developed for liquid crystal display (LCD) back-lighting and its importance is undoubtedly increasing. Some characteristics or mechanisms of the narrow-diameter lamp may be similar to those of the 36 mm one; however the similarity rule does not hold between them due to the contributions from a stepwise ionization process. Therefore, in order to clarify the excitation mechanism in the narrow-diameter lamp quantitatively, various parameters must be measured directly and some analysis must be done. The Hg+ ion density and electron density are important parameters for the purpose of clarifying the excitation mechanism quantitatively. In this work, we have measured the Hg+ ion density using the modified absorption method, and the electron density using the probe method in the Ar-Hg discharge of the 4 mm bore tube on bath temperature. Moreover, with combining the modified absorption method and the probe method, the Hg2+ molecular ion density has been determined

  18. Colloidally prepared CdHgTe and HgTe quantum dots with strong near-infrared luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Rogach, A.L.; Kornowski, A.; Eychmueller, A.; Weller, H. [Hamburg Univ. (Germany). Inst. fuer Physikalische Chemie; Harrison, M.T.; Kershaw, S.V.; Burt, M.G. [Corning Research Centre, Suffolk (United Kingdom)

    2001-03-01

    Several series of CdHgTe composite nanocrystals were prepared using thiol-capped CdTe nanocrystal precursors to which subsequent layers of HgTe and CdTe were added. The position of the 'excitonic' photoluminescence peak measured at room temperature was red-shifted to the near infrared to give emission wavelengths ranging from 800 to 1100 nm depending on the quantum dot composition, with quantum efficiency (QE) significantly increased over the pure CdTe material (QE up to around 40%). Thiol-capped HgTe nanocrystals synthesized in aqueous solution show a broad photoluminescence with a QE of {proportional_to}50%. It has been shown using D{sub 2}O as a solvent that by varying the synthesis conditions it is possible to tune the luminescence of HgTe quantum dots to the desired wavelength in the range of 900-2000 nm. HgTe nanocrystals passivated at the surface with a thick CdS layer have been shown to be much more robust towards heating and ''aging'' of the optical properties. (orig.)

  19. HgMn Stars as apparent X-ray emitters

    OpenAIRE

    Hubrig, S.; Berghoefer, W.; Mathys, G.

    1998-01-01

    In the ROSAT all-sky survey 11 HgMn stars were detected as soft X-ray emitters (Berghoefer, Schmitt & Cassinelli 1996). Prior to ROSAT, X-ray observations with the Einstein Observatory had suggested that stars in the spectral range B5-A7 are devoid of X-ray emission. Since there is no X-ray emitting mechanism available for these stars (also not for HgMn stars), the usual argument in the case of an X-ray detected star of this spectral type is the existence of an unseen low-mass companion which...

  20. Comparison of the characteristics and mechanisms of Hg(II) sorption by biochars and activated carbon.

    Science.gov (United States)

    Xu, Xiaoyun; Schierz, Ariette; Xu, Nan; Cao, Xinde

    2016-02-01

    Two biochars were produced from bagasse and hickory chips (referred to as BB and HCB, respectively) and evaluated for their sorption ability of Hg(II) in aqueous solution. A commercial activated carbon (AC) which is commonly used for Hg(II) removal was included for comparison. Both biochars showed higher sorption capacities than AC, following the trend of BB>HCB>AC. The sorption of Hg(II) by BB and AC was mainly attributed to the formation of (COO)2Hg(II) and (O)2Hg(II). As a result, the adsorption capacity of Hg(II) by BB decreased 17.6% and 37.6% after COOH and OH were blocked, respectively and that of Hg(II) by AC decreased 6.63% and 62.2% for COOH and OH hindered, respectively. However, blocking the function groups had little effect on the Hg removal by HCB since sorption of Hg(II) by HCB was mainly resulted from the π electrons of CC and CO induced Hg-π binding. Further X-ray photoelectron spectroscopy analysis indicated the possibility of reduction of the Hg(II) to Hg(I) by phenol groups or π electrons during the removal of Hg(II) by both biochars. In conclusion, biochar is more effective than activated carbon in removing Hg(II) and there exists a high potential that biochar can be a substitute of activated carbon for removal of Hg(II) from wastewater. PMID:26520810

  1. Seasonal Survey of Contaminants (Cd and Hg) and Micronutrients (Cu and Zn) in Edible Tissues of Cephalopods from Tunisia: Assessment of Risk and Nutritional Benefits

    OpenAIRE

    Rjeibi, Moncef; Metian, Marc; Hajji, Tarek; Guyot, Thierry; Rafika, Ben Chaouacha-Chekir; Bustamante, Paco

    2015-01-01

    International audience Concentrations of cadmium (Cd), copper (Cu), mercury (Hg) and zinc (Zn) were determined by atomic absorption spectrophotometry in the muscle tissues (arms and mantle) of three commercial cephalopods (Loligo vulgaris, Octopus vulgaris and Sepia officinalis) caught in three different Tunisian coastal regions. The highest concentrations found correspond to the essential elements Cu and Zn. Octopuses and cuttlefish showed the highest levels of those elements while squid ...

  2. Trace enrichment with activated carbon and determination of Ni, Hg, Sn and Cd using diethyldithiocarbamate as complexant by atomic emission spectrography (AES)

    International Nuclear Information System (INIS)

    A methods has been developed for the preconcentration and determination of trace amounts of Hg, Ni, Sn and Cd in aqueous solutions. The complexes of these elements with sodium diethyl dithiocarbamate were adsorbed on activated charcoal and determined by atomic emission spectrography d-c arc technique. Factors which affect the quantitative recovery of the microamounts of the elements were optimised. Pd was used as an internal standard. The detection limits ranged from 0.01 to 0.05 ppm. (author)

  3. Electronic structures of HgTe and CdTe surfaces and HgTe/CdTe interfaces

    Science.gov (United States)

    Schick, J. T.; Bose, S. M.; Chen, A.-B.

    1989-01-01

    A Green's-function method has been used to study the surface and interface electronic structures of the II-VI compounds HgTe and CdTe. Localized surface and resonance states near the cation-terminated (100) surface of CdTe and the anion-terminated surface of HgTe have been found for the ideal surfaces. The energies and strengths of these surface states are altered by surface perturbations. The bulk states near the surface are drastically modified by the creation of the surface, but the band gaps remain unchanged. Numerical evaluation of the local densities of states at the Gamma and J points shows that, at the (100) interface of HgTe/CdTe, the previously observed surface states are no longer present. However, in the interface region, bulk states of one material penetrate some distance into the other material.

  4. Sr(Hg{sub 1-x}Sn{sub x}){sub 4}. Variations of the EuIn{sub 4}-type structure

    Energy Technology Data Exchange (ETDEWEB)

    Wendorff, Marco; Roehr, Caroline [Freiburg Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie

    2015-07-01

    Starting from the new compound SrHg{sub 2}Sn{sub 2}, which is isoelectronic and also isotypic to the indide SrIn{sub 4}, the successive substitution of Sn against the electron poor Hg has been investigated in a combined synthetic, crystallographic, and bond-theoretical study. Along the 1:4 section Sr(Hg{sub 1-x}Sn{sub x}){sub 4} a series of compounds with Sn contents x between 0.5 and 0.2 were synthesized from stoichiometric ratios of the elements. Their crystal structures, which represent three different variants of the EuIn{sub 4}-type structure, have been determined using single crystal X-ray data. The most electron rich compound SrHg{sub 2}Sn{sub 2} crystallizes in the original EuIn{sub 4}-type [monoclinic, C2/m, a = 1257.9(14), b = 490.1(4), c = 997.8(12) pm, β = 117.60(6) , Z = 4, R1 = 0.0838], with a fully ordered Hg and Sn distribution. The four atom sites form two different folded ladders with an alternating Hg/Sn distribution. Like in the KHg{sub 2}-type, the ladders are connected via six-membered rings. In between, double tubes with an internal Sn-Sn bond are connected via further Sn-Sn bonds to form sheets similar to those observed in SiAs. The most electron-poor phase SrHg{sub 3.2}Sn{sub 0.8} crystallizes in a strongly distorted variant of this structure [a = 1172.8(4), b = 497.9(2), c = 1010.0(4) pm, β = 118.860(7) , Z = 4, R1 = 0.0549]. Herein, additional Hg-Hg bonds are formed, and the open tubes are distorted into rods of edge-sharing rhombohedra resembling the structure motifs of elemental Hg. At an intermediate valence electron (v.e.) number, i.e., in SrHg{sub 2.5}Sn{sub 1.5}, an isomorphous tripled superstructure (a = 2704.4(5), b = 493.87(7), c = 1197.1(2) pm, β = 90.838(14) , Z = 12, R1 = 0.0475) occurs, where the building blocks of the two variants of the EuIn{sub 4}-type structure alternate in a 1:2 ratio. The bonding situation and the ''coloring'', i.e., the Hg/Sn distribution in the polyanionic network, are discussed

  5. Application of a sorbent trap system to gas-phase elemental and oxidized mercury analysis.

    Science.gov (United States)

    Zhang, Zishuo; Eom, Yujin; Lee, Michelle J; Lee, Tai Gyu

    2016-07-01

    A sorbent trap that utilizes activated carbon (AC) as the solid trapping medium is a new technology for measuring total mercury (Hg) emissions from combustion facilities. In this study, sorbent trap technology was further developed, improved and evaluated at the laboratory scale. AC was impregnated with 5% aqua regia to enhance its Hg adsorption capacity. Sorbent traps spiked with an Hg standard solution were found to be reproducibly prepared and highly stable. The effect of the Hg concentration on the spiking efficiency was further investigated. The adsorption of elemental and oxidized Hg by the sorbent trap was studied under various experimental conditions (temperature, flow rate and inlet Hg concentration). The Hg concentration of the flue gas effluent from the sorbent trap was measured. In addition, the concentration of Hg adsorbed on the AC was determined by digesting the used AC with an acid according to US EPA method 3052 and then analyzing it with cold vapor atomic absorption spectrometry. Furthermore, the gas-phase Hg emissions from a combustion source were measured using the sorbent trap according to US EPA method 30B. The results showed that the sorbent trap could be used for Hg concentrations between 10.0 and 40.0 μg m(-3) and flow rates between 0.5 and 1.0 lpm with adsorption efficiencies greater than 90%. PMID:27060637

  6. Excited States in 176,178Hg and Shape Coexistence in Very Neutron-Deficient Hg Isotopes

    International Nuclear Information System (INIS)

    Excited states have been observed for the first time in the neutron-deficient 176,178Hg nuclei using the recoil-decay tagging (RDT) technique in which prompt γ rays are associated with a particular isotope through a correlation with the characteristic ground state α decay. Below N=102, the excitation energy of a rotational band built on a prolate shape (β2∼0.25) increases with decreasing mass to the point where there is no longer any evidence for its presence at low spin in 176Hg. The data are in qualitative agreement with recent mean field calculations. copyright 1997 The American Physical Society

  7. A GFP-based bacterial biosensor with chromosomally integrated sensing cassette for quantitative detection of Hg(II) in environment

    Institute of Scientific and Technical Information of China (English)

    Himanshu Priyadarshi; Absar Alam; Gireesh-Babu P; Rekha Das; Pankaj Kishore; Shivendra Kumar; Aparna Chaudhari

    2012-01-01

    A mercury biosensor was constructed by integrating biosensor genetic elements into E.coli JM109 chromosome in a single copy number,using the attP/attB recombination mechanism of λ phage.The genetic elements used include a regulatory protein gene (merR) along with operator/promoter (O/P) derived from the mercury resistance operon from pDU1358 plasmid of Serratia marcescens.The expression of reporter gene gfp is also controlled by merR/O/P.Integration of the construct into the chromosome was done to increase the stability and precision of the biosensor.This biosensor could detect Hg(Ⅱ) ions in the concentration range of 100-1700 mnol/L,and manifest the result as the expression of GFP.The GFP expression was significantly different (P ≤ 0.05) for each concentration of inducing Hg(Ⅱ) ions in the detection range,which reduces the chances of misinterpretation of results.A model using regression method was also derived for the quantification of the concentration of Hg(Ⅱ) in water samples.

  8. Simultaneous cloud point extraction of low levels of Cd, Cr and Hg in seaweed species prior to neutron activation analysis

    International Nuclear Information System (INIS)

    A one-step preconcentration cloud point extraction (CPE) method has been developed for the simultaneous determination of Cd, Cr, and Hg using a mixture of 1-(2-pyridylazo)-2-naphthol (PAN) and 1-(2-thiazolylazo)-2-naphthol (TAN) chelating agents and polyoxyethylene nonylphenylether-20 (PONPE-20) surfactant. The pH concentration of PAN and TAN, concentration of PONPE-20, ionic strength and temperature affecting the separation were optimized. The recoveries of each of the elements under the optimum conditions of pH 8.6, (PAN/TAN) = 1 X 10-4 M, (PONPE-20) = 0.1 % (m/v), ionic strength = 0.05 M KNO3, and temperature of 41 0C were > 98%. The concentrations of the elements were determined by neutron activation analysis using the Dalhousie University Slowpoke-2 reactor (DUSR) facility. The detection limits of Cd, Cr and Hg were 6.0, 3.6 and 1.2 ng g-1 respectively, and precision and accuracy of measurements were evaluated. The method was successfully applied to the simultaneous determination of Cd, Cr and Hg in fifteen Ghanaian seaweed species. (au)

  9. Use of HgI2 as gamma radiation detector

    International Nuclear Information System (INIS)

    The Mercuric Iodide (HgI2) has become one of the most promising room temperature semiconductors for the construction of X and gamma radiation detectors. The classical methods of spectroscopy have not demonstrated to achieve optimum results with HgI2 detectors, mainly due to its particular carrier transport properties. Several alternative spectroscopic methods developed in the last ten years are presented and commented, selecting for a complete study one of them: 'The Partial Charge Collection Method'. The transport properties of the carriers generated by the radiation in the detector is specially important for understanding the spectroscopic behaviour of the HgI2 detectors. For a rigorous characterization of this transport, it has been studied a digital technique for the analysis of the electric pulses produced by the radiation. Theoretically, it has been developed a Monte Carlo simulation of the radiation detection and the electronic signal treatment processes with these detectors in the energy range of 60-1300 KeV. These codes are applied to the study of the The Partial Charge Collection Method and its comparison with gaussian methods. Experimentally, this digital techniques is used for the study of the transport properties of thin HgI2 detectors. Special interest is given to the contribution of the slower carriers, the holes, obtaining some consequent of spectroscopic interest. Finally, it is presented the results obtained with the first detectors grown and mounted in CIEMAT with own technology. (author). 129 ref

  10. Photoluminescence from CdxHg1-xTe

    International Nuclear Information System (INIS)

    We present important aspects of photoluminescence (PL) of CdxHg1-xTe in the infrared part of the spectrum where background thermal radiation significantly affects the PL spectrum. We show how the background spectrum can be removed from the data. We also show how the wavelength of the excitation laser affects the relative intensity of the PL peaks from a multi-layer structure. Finally, we present temperature dependent PL of a Cd0.36Hg0.64Te/Cd0.61Hg0.39Te multiple quantum well structure grown on a 4 μm thick Cd0.36Hg0.64Te buffer layer. We attribute the low temperature peak from the buffer layer to impurities. The impurity levels are depopulated as the temperature increases, resulting in a decreased PL peak intensity. Above ∼200 K a band-to-band peak from the buffer layer is observed. The quantum well peak persists up to ∼200 K

  11. Thermodynamic investigations of CdTe-HgTe solid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Nasar, A.; Shamsuddin, M. (Dept. of Metallurgical Engineering, Banaras Hindu Univ., Varanasi (India))

    1991-08-10

    The activity of CdTe in pseudobinary CdTe-HgTe solid solution (with CdTe added in 10 mol.% increments) has been determined in the temperature range 735-840 K by an electrochemical technique using LiCl-KCl+5 wt.% CdCl{sub 2} as the molten salt electrolyte. The activity of HgTe has been calculated by Gibbs-Duhem integration using the {alpha} function. From the e.m.f. values measured at different temperatures, various partial and excess thermodynamic quantities, namely {Delta}anti G{sup M}{sub CdTe}, {Delta}anti H{sup M}{sub CdTe}, {Delta}anti S{sup XS}{sub CdTe}, {Delta}anti G{sup XS}{sub CdTe} and {Delta}anti S{sup XS}{sub CdTe}, have been obtained. The corresponding thermodynamic parameters for HgTe have also been computed. The integral molar properties of the solid solutions have been estimated from the partial quantities of the two components, CdTe and HgTe. (orig.).

  12. Decay from the superdeformed bands in {sup 194}Hg

    Energy Technology Data Exchange (ETDEWEB)

    Henry, R.G.; Khoo, T.L.; Carpenter, M.P. [and others

    1995-08-01

    Superdeformed bands in {sup 194}H g were studied using the early implementation of Gammasphere. The response functions for the Ge detectors were measured for the first time as part of this experiment. Experiments were performed with both a backed target (where the residue stopped in the Au backing) and a thin target (where the residue recoiled into vacuum). This will permit measurements of the decay times of the quasicontinuum {gamma}rays. The spectrum in coincidence with the yrast SD band in {sup 194}Hg reveals the same features as found in the quasicontinuum structure in {sup 192}Hg. These features include: statistical {gamma}rays feeding the SD band, a pronounced E2 peak from transitions feeding the SD band, a Ml/E2 bump at low energies that is associated with the last stages of feeding of the superdeformed band, and a quasicontinuous distribution from {gamma}rays linking SD and normal states, including a sizable clustering of strength around 1.7 MeV. The remarkable similarity of the spectra coincident with SD bands in {sup 192,194}Hg provides additional support for a statistical process for decay out of the SD states. This similarity contrasts with differences observed in the spectrum coincident with the SD band in the odd-even {sup 191}Hg, confirming the predictions about the role of pairing (in normal states) in influencing the shape of the decay-out spectrum.

  13. 40 CFR 60.4142 - Hg allowance allocations.

    Science.gov (United States)

    2010-07-01

    ... produced by any associated heat recovery steam generator during the control period divided by 0.8, and with... paragraph (b) of this section for each Hg Budget unit will be: (i) For units commencing operation before... paragraph (a)(1)(i)(A) or (B) of this section, multiplied by 1.0. (ii) For units commencing operation on...

  14. Theory of spin-Hall effect in HgTe

    International Nuclear Information System (INIS)

    We study theoretically a ballistic transport in HgTe H-shaped nanostructures using Landauer-Buettiker formalism. We model inverted HgTe nanostructures using realistic parameters describing properly the spin-orbit splittings and effective mass in these structures. The idea of the transport measurements is as follows. When an electric current flows in one of the legs of the H-bar structure, a transverse spin current due to the intrinsic spin-Hall effect is induced in the connecting part. Subsequently, this spin current produces, due to the inverse spin-Hall effect, a voltage difference in the opposite leg of the H-bar structure which can be measured by a voltmeter. We predict that the spin-Hall effect in H-shaped HgTe/HgCdTe inverted band structure quantum wells can be significant (on the order of a few % of the excitation voltage (microvolts)) if the size of the structure is below a ballistic length.

  15. Distribuição de Hg total e suas associações com diferentes suportes geoquímicos em sedimentos marinhos da margem continental brasileira: Bacia de Campos - Rio de Janeiro Total mercury distribution and its association with diferent geochemical supports in marine sediment from the brazilian continental margin: Campos Basin

    Directory of Open Access Journals (Sweden)

    Beatriz Ferreira Araujo

    2010-01-01

    Full Text Available Mercury distribution and geochemical support on the Continental Margin was evaluated at the Campos Basin, Rio de Janeiro state, Brazil. The average concentrations for all analyzed elements were, respectively, 20 ± 5 ng g-1 (Hg; 30 ± 14 mg g-1 (Al; 16 ± 6 mg g-1 (Fe, and 254 ± 83 µg g-1 (Mn. Silt and clay content, total carbonate and Hg, and organic carbon increased with depth. Finally, the relationship between Hg and silt clay showed significant positive correlation. Total Hg concentrations are the background level described primarily (~40 ng g-1.

  16. Study of atomic structure of liquid Hg-In alloys using ab-initio molecular dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Nalini; Ahluwalia, P. K. [Department of Physics, Himachal Pradesh University, Shimla(HP)-171005 (India); Thakur, Anil [Department of Physics, Govt. P. G. College Solan (HP)-173212 (India)

    2015-05-15

    Ab-initio molecular dynamics simulations are performed to study the structural properties of liquid Hg-In alloys. The interatomic interactions are described by ab-initio pseudopotentials given by Troullier and Martins. Five liquid Hg-In mixtures (Hg{sub 10}In{sub 90}, Hg{sub 30}In{sub 70}, Hg{sub 50}In{sub 50}, Hg{sub 70}In{sub 30} and Hg{sub 90}In{sub 10}) at 299K are considered. The radial distribution function g(r) and structure factor S(q) of considered alloys are compared with respective experimental results for liquid Hg (l-Hg) and (l-In). The radial distribution function g(r) shows the presence of short range order in the systems considered. Smooth curves of Bhatia-Thornton partial structure factors factor shows the presence of liquid state in the considered alloys.

  17. Study of atomic structure of liquid Hg-In alloys using ab-initio molecular dynamics

    International Nuclear Information System (INIS)

    Ab-initio molecular dynamics simulations are performed to study the structural properties of liquid Hg-In alloys. The interatomic interactions are described by ab-initio pseudopotentials given by Troullier and Martins. Five liquid Hg-In mixtures (Hg10In90, Hg30In70, Hg50In50, Hg70In30 and Hg90In10) at 299K are considered. The radial distribution function g(r) and structure factor S(q) of considered alloys are compared with respective experimental results for liquid Hg (l-Hg) and (l-In). The radial distribution function g(r) shows the presence of short range order in the systems considered. Smooth curves of Bhatia-Thornton partial structure factors factor shows the presence of liquid state in the considered alloys

  18. Studies of toxic effects of Hg(II) on Pistia stratiotes

    Energy Technology Data Exchange (ETDEWEB)

    De, A.K.; Sen, A.K.; Modak, D.P.; Jana, S.

    1985-04-01

    The uptake of Hg(II) and toxicity effect of the metal on some biochemical parameters in Pistia stratiotes L. were studied. The uptake of Hg(II) by the plants gradually increased with increase in concentration of Hg(II) in the culture medium. Maximum accumulation of Hg(II) was noted within 1 day. Maximum removal (about 90%) of Hg(II) was recorded below 20 ppm Hg(II). Accumulation of Hg(II) in roots was about four times higher than that in shoots. At 20 ppm, Hg(II) promoted senescence of Pistia plants by decreasing chlorophyll, protein RNA, dry weight and activities of catalase and protease as well as increasing free amino acid content, peroxidase activity and the ratio of acid to alkaline pyrophosphatase activity over control values. At Hg concentrations below 20 ppm these constituents were least affected.

  19. History of HgTe-based photodetectors in Poland

    Science.gov (United States)

    Rogalski, A.

    2010-09-01

    In Poland, the HgCdTe studies began in 1960 at the Institute of Physics, Warsaw University. The material processing laboratory was created by Giriat and later by Dziuba, Gałązka, and others. Bridgman technique with sealed thick wall quartz ampoules was used to grow material suitable for research and experimental devices. Among the first papers published in 1961 and 1963 there were the Polish works devoted to preparation, doping, and electrical properties of HgCdTe. Infrared detector's research and development efforts in Poland were concentrated mostly on uncooled market niche. At the beginning, a modified isothermal vapour phase epitaxy has been used for research and commercial fabrication of photoconductive, photoelectromagnetic and other HgCdTe devices. Bulk growth and liquid phase epitaxy were also used. Recently, the fabrication of infrared devices relies on low temperature epitaxial technique, namely metalorganic vapour phase deposition. At present stage of development, the photoconductive and photoelectromagnetic (PEM) detectors are gradually replaced with photovoltaic devices which offer inherent advantages of no electric or magnetic bias, no heat load and no flicker noise. Potentially, photodiodes offer high performance and very fast response. However, conventional photovoltaic uncooled detectors suffer from low quantum efficiency and very low junction resistance. The problems have been solved with advanced band gap engineered architecture, multiple cell heterojunction devices connected in series, and monolithic integration of the detectors with microoptics. In final part of the paper, the Polish achievements in technology and performance of HgMnTe and HgZnTe photodetectors are presented.

  20. Selected elements in fly agaric Amanita muscaria.

    Science.gov (United States)

    Falandysz, J; Kunito, T; Kubota, R; Lipka, K; Mazur, A; Falandysz, Justyna J; Tanabe, S

    2007-09-01

    Concentrations of Ag, Al, Ba, Ca, Cd, Co, Cu, Cr, Cs, Fe, Ga, Hg, K, Mg, Mn, Mo, Na, Pb, Rb, Se, Sb, Sr, V, Tl and Zn have been determined in the whole fruiting bodies, as well as separately in caps and stalks, of fly agaric collected from three geographically distant sites in northern part of Poland. The elements were determined using ICP-MS, ICP-OES, HG-AAS and CV-AAS, respectively. For elements such as Al, Ba, Cr, Fe, Ga, Mo, Mn, Pb, Sb, Sr, Tl, and V concentrations were similar in the caps and stalks, respectively, and for K, Zn, Ag, Ca, Cd, Cu, Hg, Mg, Rb and Se were greater in the caps, while for Co, Cs and Na in the stalks. For Ag, Al, Ba, Ca, Cd, Co, Cr, Cs, Fe, Ga, Hg, Mn, Mo, Pb, Rb, Sb, Sr, Tl and V concentration in the caps showed spatial variations (P<0.05), while for Cu, K, Mg, Na, Se and Zn was independent of the site. The elements such as K with median or mean in the caps between 37,000 and 43,000 microg/g.dm and Mg with 920 and 1,100 microg/g dm were most abundant. Next, within median values range from approximately 100 to 500 microg/g dm were such as Ca, Fe and Al, and in descending order they followed by Rb (100-400 microg/g dm); V, Na, Zn (50-200 microg/g dm); Cu, Mn (10-50 microg/g dm); Cd (10-20 microg/g dm); Se (5 microg/g dm); Ba (<1-3); Cr, Ag, Pb, Sr (<1-2 microg/g dm); Cs, Co, Hg (<1-1 microg/g dm); Ga (<0.5), Sb, Mo and Tl (<0.1 microg/g dm). PMID:17849303

  1. A synthesis of rates and controls on elemental mercury evasion in the Great Lakes Basin

    International Nuclear Information System (INIS)

    Rates of surface-air elemental mercury (Hg0) fluxes in the literature were synthesized for the Great Lakes Basin (GLB). For the majority of surfaces, fluxes were net positive (evasion). Digital land-cover data were combined with representative evasion rates and used to estimate annual Hg0 evasion for the GLB (7.7 Mg/yr). This value is less than our estimate of total Hg deposition to the area (15.9 Mg/yr), suggesting the GLB is a net sink for atmospheric Hg. The greatest contributors to annual evasion for the basin are agricultural (∼55%) and forest (∼25%) land cover types, and the open water of the Great Lakes (∼15%). Areal evasion rates were similar across most land cover types (range: 7.0–21.0 μg/m2-yr), with higher rates associated with urban (12.6 μg/m2-yr) and agricultural (21.0 μg/m2-yr) lands. Uncertainty in these estimates could be partially remedied through a unified methodological approach to estimating Hg0 fluxes. - Highlights: ► Considerable variability exists across spatial/temporal scales in Hg0 evasion rates. ► Methodological approaches vary for estimating and reporting gaseous Hg0 fluxes. ► Hg0 evasion from the Great Lakes Basin is estimated at 7.7 Mg/yr (10.2 μg/m2-yr). ► Hg flux estimates suggest region is a net sink for atmospheric Hg. ► 95% of Hg0 evasion in the region is from agriculture, forest, and the Great Lakes. - A synthesis of Hg evasion was conducted and this information was used to develop an estimate of Hg evasion for the Great Lakes Basin.

  2. X-ray absorption of the Hg distribution in a commercial metal-halide lamp

    Energy Technology Data Exchange (ETDEWEB)

    Nimalasuriya, T; Zhu, X; Ridderhof, E J; Beks, M L; Haverlag, M; Denisova, N; Stoffels, W W; Mullen, J J A M van der [Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands)], E-mail: T.Nimalasuriya@tue.nl

    2008-07-21

    The radial temperature profiles of a commercial metal-halide lamp and of lamps containing its individual components have been acquired using x-ray absorption of Hg density distribution. The temperature profiles were determined by combining the measured absorption of the spatially resolved Hg density with the wall temperature. The lamps studied were a commercial lamp, i.e. the Philips CDM-T 70 W/830, and identically shaped lamps containing NaI, DyI{sub 3} and TlI separately. It was found that the element Dy contracts the arc, Na broadens the arc while Tl causes the arc to have so-called 'shoulders'. Combined in the commercial lamp this leads to a wall-stabilized arc without contraction and 'shoulders'. A reproducibility test with identical lamps was also made and showed that the uncertainty in the temperature profile is about 8% for the absolute temperature and only 1.6% for the actual shape of the profile.

  3. Decay studies and mass measurements on isobarically pure neutron-rich Hg and Tl isotopes

    CERN Multimedia

    Schweikhard, L C; Savreux, R P; Hager, U D K; Beck, D; Blaum, K

    2007-01-01

    We propose to perform mass measurements followed by $\\beta$- and $\\gamma$-decay studies on isobarically pure beams of neutron-rich Hg and Tl isotopes, which are very poorly known due to a large contamination at ISOL-facilities with surface-ionised francium. The aim is to study the binding energies of mother Hg and Tl nuclides, as well as the energies, spins and parities of the excited and ground states in the daughter Tl and Pb isotopes. The proposed studies will address a new subsection of the nuclear chart, with Z 126, where only 9 nuclides have been observed so far. Our studies will provide valuable input for mass models and shell-model calculations: they will probe the proton hole-neutron interaction and will allow to refine the matrix elements for the two-body residual interaction. Furthermore, they also give prospects for discovering new isomeric states or even new isotopes, for which the half-lives are predicted in the minute- and second-range.\\\\ To reach the isobaric purity, the experiments will be p...

  4. Fingerprint of different spin-orbit terms for spin transport in HgTe quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Rothe, D G; Reinthaler, R W; Liu, C-X; Hankiewicz, E M [Institut fuer Theoretische Physik und Astrophysik, Universitaet Wuerzburg, 97074 Wuerzburg (Germany); Molenkamp, L W [Physikalisches Institut (EP3), Universitaet Wuerzburg, 97074 Wuerzburg (Germany); Zhang, S-C, E-mail: hankiewicz@physik.uni-wuerzburg.d [Department of Physics, McCullough Building, Stanford University, Stanford, CA 94305-4045 (United States)

    2010-06-15

    Using k{center_dot}p theory, we derive an effective four-band model describing the physics of the typical two-dimensional topological insulator (HgTe/CdTe quantum well (QW)) in the presence of an out-of-plane (in the z-direction) inversion breaking potential and an in-plane potential. We find that up to third order in perturbation theory, only the inversion breaking potential generates new elements to the four-band Hamiltonian that are off-diagonal in spin space. When this new effective Hamiltonian is folded into an effective two-band model for the conduction (electron) or valence (heavy hole) bands, two competing terms appear: (i) a Rashba spin-orbit interaction originating from inversion breaking potential in the z-direction and (ii) an in-plane Pauli term as a consequence of the in-plane potential. Spin transport in the conduction band is further analysed within the Landauer-Buettiker formalism. We find that for asymmetrically doped HgTe QWs, the behaviour of the spin-Hall conductance is dominated by the Rashba term.

  5. Subcellular localization of several heavy metals of Hg,Cd and Pb in human liver

    Institute of Scientific and Technical Information of China (English)

    CHEN Chunying; ZHANG Peiqun; CHAI Zhifang

    2005-01-01

    Liver, as an important metabolic and detoxicological organ of human body, can be used as a good bioindicator for evaluating body burden of environmental pollutants. Its elemental contents and their chemical forms are closely related to the status of human health and disease. In this paper, the liver samples collected from normal subjects were separated to different subcellular fractions of nuclei, mitochondria, lysosome, microsome and cytosol by differential centrifugation. Then their concentrations of heavy metals of As, Pb, Cd, and Hg were determined by atomic absorption and atomic fluorescent spectroscopy. Our results show no significant difference with literature ones when comparing their gross concentrations. In the case of their subcellular distribution, the Hg concentrations are higher in mitochondrial, microsomal and cytosolic fractions; the Cd concentrations are higher in cytosolic and mitochondrial fractions, while As highest in nuclear fraction. The highest concentration of Pb is found in microsomal fraction with similarity to Fe. Mercury in liver is mainly in the form of inorganic, and methylmercury ranged from 9% to 50% with the average value of 20.9%(13.3%. These results indicate that the cellular distribution and the accumulated target organelles are quite different among these heavy metals, which suggest their various pathways and toxic mechanism in vivo.

  6. Spatial distribution of dissolved Pb,Hg,Cd,Cu and As in the Bohai Sea

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Characteristics of the spatial distribution of selected dissolved heavy metals were analyzed during large scale surveys from August 12 to 25.2003 in the Bohai Sea.Dissolved Pb was the only element with average concentrations higher than the grade-one sea water quality standard of China.The spatial distribution of dissolved Pb in surface water was similar to those of Cd,Cu and As,where the isopleths generally indicated decreasing values from the bays to the central areas.Only for Hg did the high concentrations not only appear in Liaodong Bay,Bohai Bay and Laizhou Bay,but also in the Central Area,viz.not only in inshore but also in offshore areas.Vertical distributions of dissolved Pb,Cd,Cu and As were largely uniform,while that of dissolved Hg increased with depth.We infer that the input of pollutants from land was the main influencing factor for the detected distribution patterns of dissolved heavy metals,followed by the dynamics of sea water,release from bottom sediments and biochemical processes.Comparing with historical data,average concentrations of dissolved heavy metals appear to decline in recent years.

  7. Beer Law Constants and Vapor Pressures of HgI2 over HgI2(s,l)

    Science.gov (United States)

    Su, Ching-Hua; Zhu, Shen; Ramachandran, N.; Burger, A.

    2002-01-01

    Optical absorption spectra of the vapor phase over HgI2(s,l) were measured at sample temperatures between 349 and 610 K for wavelengths between 200 and 600 nm. The spectra show the samples sublimed congruently into HGI2 without any observed Hg or I2 absorption spectra. The Beer's Law constants for 15 wavelengths between 200 and 440 nm were derived. From these constants the vapor pressure of HgI2, P, was found to be a function of temperature for the liquid and the solid beta-phases: ln P(atm) = -7700/T(K) + 12.462 (liquid phase) and ln P(atm) = -10150/T(K) + 17.026 (beta-phase). The expressions match the enthalpies of vaporization and sublimation of 15.30 and 20.17 kcal/mole respectively, for the liquid and the beta-phase HgI2. The difference in the enthalpies gives an enthalpy of fusion of 4.87 kcal/mole, and the intersection of the two expressions gives a melting point of 537 K.

  8. HgCdTe e-APD detector arrays with single photon sensitivity for space lidar applications

    Science.gov (United States)

    Sun, Xiaoli; Abshire, James B.; Beck, Jeffrey D.

    2014-05-01

    A multi-element HgCdTe electron initiated avalanche photodiode (e-APD) array has been developed for space lidar. The detector array was fabricated with 4.3μm cutoff HgCdTe with a spectral response from 0.4 to 4.3 μm. We have demonstrated a 4x4 e-APD array with 80 μm square elements followed by a custom cryogenic CMOS read-out integrated circuit (ROIC). The device operates at 77K inside a small closed-cycle cooler-Dewar with the support electronics integrated in a field programmable gate array. Measurements showed a unity gain quantum efficiency of about 90% at 1.5-1.6 μm wavelength. The bulk dark current of the HgCdTe e-APD at 77K was less than 50,000 input referred electrons/s at 12 V APD bias where the APD gain was 620 and the measured noise equivalent power (NEP) was 0.4 fW/Hz1/2. The electrical bandwidth of the device was about 6 MHz, mostly limited by the ROIC, but sufficient for the lidar application. Although the devices were designed for low bandwidth pulse detections, the high gain and low dark current enabled them to be used for single photon detections. Because the APD was biased below the break-down voltage, the output is linear to the input signal and there were no nonlinear effect such as dead-time and afterpulsing, and no need for gated operation. A new series of HgCdTe e-APDs have also been developed with a much wider bandwidth ROIC and higher APD gain, which is expected to give a much better performance in single photon detections.

  9. Hg, Bi, Cu and Zn distribution in human teeth treated by dental amalgam measured by synchrotron microprobe

    International Nuclear Information System (INIS)

    Human teeth restored with dental amalgam were analysed by a synchrotron microprobe to evaluate the diffusion of its major constituents, Cu, Zn and Hg, throughout the tooth structures. We measured the elemental distribution inside the tooth from the root to the enamel, specially the region around the amalgam, after its total removal. Hg is present only in restored teeth and concentration profiles show strongly increased levels of this element close to the amalgam region, reaching 500 μg g-1 in one or two cases, decreasing strongly to the inner part of the tooth. Pb concentration profiles do not seem to be affected by metallic amalgam. Very high concentrations of Bi were found in one of the restored teeth, reaching more than 2000 μg g-1, decreasing sharply to the outer regions. The distribution of Mn, Fe, Cu and Zn was also determined in order to evaluate elemental influences by amalgam components. No significant changes in elemental concentrations were detected for Mn and Fe between healthy and restored teeth. However, the levels of Zn and Cu are increased in restored teeth. An X-ray fluorescence set-up with microprobe capabilities, 100 μm of spatial resolution and an energy of 18 keV, installed at LURE synchrotron (France) was used

  10. Hg, Bi, Cu and Zn distribution in human teeth treated by dental amalgam measured by synchrotron microprobe

    Science.gov (United States)

    Carvalho, M. L.; Marques, J. P.; Brito, J.; Casaca, C.; Cunha, A. S.

    2002-11-01

    Human teeth restored with dental amalgam were analysed by a synchrotron microprobe to evaluate the diffusion of its major constituents, Cu, Zn and Hg, throughout the tooth structures. We measured the elemental distribution inside the tooth from the root to the enamel, specially the region around the amalgam, after its total removal. Hg is present only in restored teeth and concentration profiles show strongly increased levels of this element close to the amalgam region, reaching 500 μg g -1 in one or two cases, decreasing strongly to the inner part of the tooth. Pb concentration profiles do not seem to be affected by metallic amalgam. Very high concentrations of Bi were found in one of the restored teeth, reaching more than 2000 μg g -1, decreasing sharply to the outer regions. The distribution of Mn, Fe, Cu and Zn was also determined in order to evaluate elemental influences by amalgam components. No significant changes in elemental concentrations were detected for Mn and Fe between healthy and restored teeth. However, the levels of Zn and Cu are increased in restored teeth. An X-ray fluorescence set-up with microprobe capabilities, 100 μm of spatial resolution and an energy of 18 keV, installed at LURE synchrotron (France) was used.

  11. Hg, Bi, Cu and Zn distribution in human teeth treated by dental amalgam measured by synchrotron microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, M.L. E-mail: luisa@cii.fc.ul.pt; Marques, J.P.; Brito, J.; Casaca, C.; Cunha, A.S

    2002-11-01

    Human teeth restored with dental amalgam were analysed by a synchrotron microprobe to evaluate the diffusion of its major constituents, Cu, Zn and Hg, throughout the tooth structures. We measured the elemental distribution inside the tooth from the root to the enamel, specially the region around the amalgam, after its total removal. Hg is present only in restored teeth and concentration profiles show strongly increased levels of this element close to the amalgam region, reaching 500 {mu}g g{sup -1} in one or two cases, decreasing strongly to the inner part of the tooth. Pb concentration profiles do not seem to be affected by metallic amalgam. Very high concentrations of Bi were found in one of the restored teeth, reaching more than 2000 {mu}g g{sup -1}, decreasing sharply to the outer regions. The distribution of Mn, Fe, Cu and Zn was also determined in order to evaluate elemental influences by amalgam components. No significant changes in elemental concentrations were detected for Mn and Fe between healthy and restored teeth. However, the levels of Zn and Cu are increased in restored teeth. An X-ray fluorescence set-up with microprobe capabilities, 100 {mu}m of spatial resolution and an energy of 18 keV, installed at LURE synchrotron (France) was used.

  12. On the morphology and crystallography of Hg5In2Te8 precipitation in Hg3In2Te6

    International Nuclear Information System (INIS)

    Highlights: • The crystallography between Hg5In2Te8 and Hg3In2Te6 has been studied by TEM. • The precipitates have three variants with a 〈0 0 1〉m growth direction. • Near-CSL calculation suggests 0° or 90° mutual rotation to reach the lowest Σ value. - Abstract: Transmission electron microscopy to investigate the crystallography of Hg5In2Te8 precipitation in single crystals of Hg3In2Te6. Both the matrix and precipitate phases were confirmed to have the F4¯3m space group. The lattice constant of the precipitates was measured to be a = 1.27 nm, which is approximately double that of the matrix (0.63 nm). Three crystallographically equivalent variants of the precipitate phase were observed to exhibit a cylindrical morphology, dispersed uniformly throughout the matrix. The preferred growth direction of all three variants was along 〈0 0 1〉m. The crystallographic orientation relationship (OR) between the precipitates and matrix was found to be a cubic parallel OR. High resolution imaging indicated that the precipitate–matrix interface was fully coherent. The precipitate crystals were found to correspond to the lowest sigma value of the near coincidence site lattices when performing a 0° or 90° mutual rotation. Finally, the existence of Hg5In2Te8 precipitation was found to have a negative effect on the optical properties according to the infrared transmittance measurement. The results in this paper may have a guiding significance on the relationship between the precipitate and optical properties of similar materials

  13. Studies of the levels of Cd, Hg, Mn, Se and Zn in Marine Fish Species commonly available and highly consumed in Ghana

    International Nuclear Information System (INIS)

    Marine fish is one of the main sources of dietary exposure to Hg and Cd. High levels of Hg and Cd are often reported in marine fishes, creating the impression that the mere consumption of marine fish exposes humans to the toxic effects of Cd and Hg. These reports often ignore the protective effects of Se against Hg toxicity. Mn and Zn also moderate the toxic effects of Cd. Consequently, the use of the levels of Hg and Cd alone without considering the levels of Se, Mn and Zn, and their antagonistic interaction is not appropriate and leads to misinformation. Antagonistic interaction between Se-Hg, Zn-Cd, and Mn-Cd, are essential factors in evaluating the health risk associated with dietary exposure to Cd and Hg due to fish consumption. the interacton depends on the concentratiions (µmol kg-1) of the elements and the molar ratios of the respective interacting pairs of elements. This study evaluated the antagonistic interaction [through estimation of concentration (µmol kg-1), molar ratios and the health benefit value (for selenium only)] between cadmium (Cd)- manganese(Mn), cadmium (Cd)- zinc (Zn) and selenium (Se)-mercury (Hg) in the nine (9) marine fish species. This fish species are Frigate tuna (Auxis thazard), African forktail snapper (Apsilus fuscus), Bigeye forstfish (Benthodesmus elongatus), Blue runner (Caranx crysos), Atlantic herrings (Clupea harengus), Smooth puffer (Lagocephalus laevigatusP, Brown shrimps (metapenaeus monoceros), Round sardinella (Sardinella aurita) and African moonfish (Selene dorsalis). This was achieved through the determination of the concerntrations(µg g-1) of Cd and Zn by flame atomic absorption spectrometry (FAAS), Se by hydride generation atomic absorption spectrometry (HG-AAS), and Mn by instrumental neutron activation analysis (INAA) in the lyophilized fish species. Hg in the lyophilized fish species was determined by HG-AAS after extraction of Hg in the fish species as the dithizonate using dithizonu as ligand and CHCL3 as

  14. Factors influencing the large-scale distribution of Hg° in the Mexico City area and over the North Pacific

    Directory of Open Access Journals (Sweden)

    D. Blake

    2007-11-01

    Full Text Available Gas-phase elemental mercury (Hg° was measured aboard the NASA DC-8 aircraft during the Intercontinental Chemical Transport Experiment Phase B (INTEX-B campaign in spring 2006. Flights were conducted around Mexico City and on two subsequent deployments over the North Pacific based out of Honolulu, Hawaii and Anchorage, Alaska. Data obtained from 0.15–12 km altitude showed that Hg° exhibited a relatively constant vertical profile centered around 100 ppqv. Highly concentrated pollution plumes emanating from the Mexico City urban agglomeration revealed that mixing ratios of Hg° as large as 500 ppqv were related to combustion tracers such as CO, but not SO2 which is presumably released locally from coal burning, refineries, and volcanoes. Our analysis of Mexico City plumes indicated that widespread multi-source urban/industrial emissions may have a more important influence on Hg° than specific point sources. Over the Pacific, correlations with CO, CO2, CH4, and C2Cl4 were diffuse overall, but recognizable on flights out of Anchorage and Honolulu. In distinct plumes originating from the Asian continent the Hg°- CO relationship yielded an average value of ~0.56 ppqv/ppbv, in good agreement with previous findings. A prominent feature of the INTEX-B dataset was frequent total depletion of Hg° in the upper troposphere when stratospherically influenced air was encountered. Ozone data obtained with the differential absorption lidar (DIAL showed that the stratospheric impact on the tropospheric column was a common and pervasive feature on all flights out of Honolulu and Anchorage. We propose that this is likely a major factor driving large-scale seasonality in Hg° mixing ratios, especially at mid-latitudes, and an important process that should be incorporated into global chemical transport models.

  15. Factors influencing the large-scale distribution of Hg° in the Mexico City area and over the North Pacific

    Directory of Open Access Journals (Sweden)

    D. Blake

    2008-04-01

    Full Text Available Gas-phase elemental mercury (Hg° was measured aboard the NASA DC-8 aircraft during the Intercontinental Chemical Transport Experiment Phase B (INTEX-B campaign in spring 2006. Flights were conducted around Mexico City and on two subsequent deployments over the North Pacific based out of Honolulu, Hawaii and Anchorage, Alaska. Data obtained from 0.15–12 km altitude showed that Hg° exhibited a relatively constant vertical profile centered around 100 ppqv. Highly concentrated pollution plumes emanating from the Mexico City urban agglomeration revealed that mixing ratios of Hg° as large as 500 ppqv were related to combustion tracers such as CO, but not SO2 which is presumably released locally from coal burning, refineries, and volcanoes. Our analysis of Mexico City plumes indicated that widespread multi-source urban/industrial emissions may have a more important influence on Hg° than specific point sources. Over the Pacific, correlations with CO, CO2, CH4, and C2Cl4 were diffuse overall, but recognizable on flights out of Anchorage and Honolulu. In distinct plumes originating from the Asian continent the Hg°- CO relationship yielded an average value of ~0.56 ppqv/ppbv, in good agreement with previous findings. A prominent feature of the INTEX-B dataset was frequent total depletion of Hg° in the upper troposphere when stratospherically influenced air was encountered. Ozone data obtained with the differential absorption lidar (DIAL showed that the stratospheric impact on the tropospheric column was a common and pervasive feature on all flights out of Honolulu and Anchorage. We propose that this is likely a major factor driving large-scale seasonality in Hg° mixing ratios, especially at mid-latitudes, and an important process that should be incorporated into global chemical transport models.

  16. Maternal-fetal distribution of mercury ( sup 203 Hg) released from dental amalgam fillings

    Energy Technology Data Exchange (ETDEWEB)

    Vimy, M.J.; Takahashi, Y.; Lorscheider, F.L. (Univ. of Calgary, Alberta (Canada))

    1990-04-01

    In humans, the continuous release of Hg vapor from dental amalgam tooth restorations is markedly increased for prolonged periods after chewing. The present study establishes a time-course distribution for amalgam Hg in body tissues of adult and fetal sheep. Under general anesthesia, five pregnant ewes had twelve occlusal amalgam fillings containing radioactive 203Hg placed in teeth at 112 days gestation. Blood, amniotic fluid, feces, and urine specimens were collected at 1- to 3-day intervals for 16 days. From days 16-140 after amalgam placement (16-41 days for fetal lambs), tissue specimens were analyzed for radioactivity, and total Hg concentrations were calculated. Results demonstrate that Hg from dental amalgam will appear in maternal and fetal blood and amniotic fluid within 2 days after placement of amalgam tooth restorations. Excretion of some of this Hg will also commence within 2 days. All tissues examined displayed Hg accumulation. Highest concentrations of Hg from amalgam in the adult occurred in kidney and liver, whereas in the fetus the highest amalgam Hg concentrations appeared in liver and pituitary gland. The placenta progressively concentrated Hg as gestation advanced to term, and milk concentration of amalgam Hg postpartum provides a potential source of Hg exposure to the newborn. It is concluded that accumulation of amalgam Hg progresses in maternal and fetal tissues to a steady state with advancing gestation and is maintained. Dental amalgam usage as a tooth restorative material in pregnant women and children should be reconsidered.

  17. Maternal-fetal distribution of mercury (203Hg) released from dental amalgam fillings

    International Nuclear Information System (INIS)

    In humans, the continuous release of Hg vapor from dental amalgam tooth restorations is markedly increased for prolonged periods after chewing. The present study establishes a time-course distribution for amalgam Hg in body tissues of adult and fetal sheep. Under general anesthesia, five pregnant ewes had twelve occlusal amalgam fillings containing radioactive 203Hg placed in teeth at 112 days gestation. Blood, amniotic fluid, feces, and urine specimens were collected at 1- to 3-day intervals for 16 days. From days 16-140 after amalgam placement (16-41 days for fetal lambs), tissue specimens were analyzed for radioactivity, and total Hg concentrations were calculated. Results demonstrate that Hg from dental amalgam will appear in maternal and fetal blood and amniotic fluid within 2 days after placement of amalgam tooth restorations. Excretion of some of this Hg will also commence within 2 days. All tissues examined displayed Hg accumulation. Highest concentrations of Hg from amalgam in the adult occurred in kidney and liver, whereas in the fetus the highest amalgam Hg concentrations appeared in liver and pituitary gland. The placenta progressively concentrated Hg as gestation advanced to term, and milk concentration of amalgam Hg postpartum provides a potential source of Hg exposure to the newborn. It is concluded that accumulation of amalgam Hg progresses in maternal and fetal tissues to a steady state with advancing gestation and is maintained. Dental amalgam usage as a tooth restorative material in pregnant women and children should be reconsidered

  18. Design and synthesis of BODIPY-clickate based Hg(2+) sensors: the effect of triazole binding mode with Hg(2+) on signal transduction.

    Science.gov (United States)

    Vedamalai, Mani; Kedaria, Dhaval; Vasita, Rajesh; Mori, Shigeki; Gupta, Iti

    2016-02-14

    BODIPY-clickates, F1 and F2, for the detection of Hg(2+) have been designed, synthesized and characterized. Both F1 and F2 showed hyperchromic shifts in the UV-visible spectra in response to increasing Hg(2+) concentrations. Hg(2+) ion binding caused perturbation of the emission quenching process and chelation induced enhanced bathochromic emission of F1 and F2 to 620 nm and 660 nm, respectively. Job's plot clearly indicated that the binding ratio of F1 and F2 with Hg(2+) was 1 : 1. The NMR titration of BODIPY-clickates with Hg(2+) confirmed that aromatic amines and triazoles were involved in the binding event. Furthermore, HRMS data of F1-Hg(2+) and F2-Hg(2+) supported the formation of mercury complexes of BODIPY-clickates. The dissociation constant for the interaction between fluorescent probes F1 and F2 with Hg(2+) was found to be 24.4 ± 5.1 μM and 22.0 ± 3.9 μM, respectively. The Hg(2+) ion induced fluorescence enhancement was almost stable in a pH range of 5 to 8. Having less toxicity to live cells, both the probes were successfully used to map the Hg(2+) ions in live A549 cells. PMID:26743311

  19. The peculiar abundance pattern of the new Hg-Mn star HD 30085

    CERN Document Server

    Monier, R; Royer, F; Griffin, R E M

    2015-01-01

    Using high-dispersion, high-quality spectra of HD 30085 obtained with the echelle spectrograph SOPHIE at Observatoire de Haute Provence, we show that this star contains strong lines of the s-process elements Sr II, Y II and Zr II. Line syntheses of the lines yield large overabundances of Sr, Y, Zr which are characteristic of HgMn stars. The Sr-Y-Zr triad of abundances is inverted in HD 30085 compared to that in our solar system. The violation of the odd-even rule suggests that physical processes such as radiative diffusion, chemical fractionation and others must be at work in the atmosphere of HD 30085, and that the atmosphere is stable enough to sustain them.

  20. Numerical Simulation of the Modulation Transfer Function in HgCdTe Detector Arrays

    Science.gov (United States)

    Pinkie, Benjamin; Bellotti, Enrico

    2014-08-01

    In this work, we develop a method for simulating the modulation transfer function (MTF) of infrared detector arrays, which is based on numerical evaluation of the detector physics. The finite-difference time-domain and finite element methods are used to solve the electromagnetic and electrical equations for the device, respectively. We show how the total MTF can be deconvolved to examine the effects of specific physical processes. We introduce the MTF area difference and use it to quantify the effectiveness of several crosstalk mitigation techniques in improving the system MTF. We then apply our simulation methods to two-thirds generation mercury cadmium telluride (HgCdTe) detector architectures. The methodology is general, can be implemented with commercially available software, has experimentally realizable analogs, and is extendable to other material systems and device designs.

  1. Proton irradiation of MWIR HgCdTe/CdZnTe

    Science.gov (United States)

    Fahey, Stephen; Velicu, Silviu; Bommena, Ramana; Zhao, Jun; Cowan, Vincent; Morath, Christian; Sivananthan, Sivalingam

    2015-09-01

    High performance infrared sensors are vulnerable to slight changes in defect densities and locations. For example in a space application where such sensors are exposed to proton irradiation capable of generating point defects the sensors are known to suffer performance degradation. The degradation can generally be observed in terms of dark current density and responsivity degradations. Here we report results of MWIR HgCdTe/CdZnTe single element diodes dark current densities before and after exposure to 63MeV protons at room temperature to a total ionizing dose of 100 kRad(Si). We find the irradiated diodes as a group show some signs of proton-induced damage in dark current.

  2. Transuranium elements

    International Nuclear Information System (INIS)

    This paper reports that neutron irradiation of uranium, beginning in 1934, led to the reported discovery of such transuranium elements as eka-rhenium. After a few years of investigation these were correctly identified, in December 1938, as fission products. The first real transuranium elements, with atomic numbers 93 and 94 (neptumiun and plutionium), were discovered in 1940-1941. Plutomiun-239 was shown to be fission-able with slow neutrons, and chemical methods for its separation in quantity were developed. Not until it was recognized that transuranium elements should be part of a 14-member actinide series could elements 95 and 96 (americium and curium) be chemically identified after their nuclear synthesis. This new view was the key to the synthesis and identified after their nuclear synthesis. This new view was the key to the synthesis and identification of the next seven transuranium elements, resulting in the completion of the actinide series at element 103 in 1961. The transactinide elements could, according to the actinide concept, also be correctly placed in the periodic table, and the chemical properties of the first transactinide elements, elements 104 and 105 (rutherfordium and hafnium), confirm this point of view. Transuranium elements through number 109 are now known

  3. Determination of Fe, Hg, Mn, and Pb in three-rings of poplar (Populus alba L.) by U-shaped DC arc

    Science.gov (United States)

    Marković, D. M.; Novović, I.; Vilotić, D.; Ignjatović, Lj.

    2007-09-01

    The U-shaped DC arc with aerosol supply was applied for the determination of Fe, Hg, Mn, and Pb in poplar (Populus alba L.) tree-rings. By optimization of the operating parameters and by selection of the most appropriate signal integration time (20 s for Fe, Mn, and Pb and 30 s for Hg), the obtained limits of detection for Fe, Hg, Mn, and Pb are 5.8, 2.6, 1.6, and 2.0 ng/ml, respectively. The detection limits achieved by this method for Fe, Hg, Mn, and Pb are comparable with the detection limits obtained for these elements by such methods as inductively coupled plasma-atomic emission spectrometry (ICP-AES), direct coupled plasmatomic emission spectrometry (DCP-AES), and microwave-induced plasma-atomic emission spectrometry (MIP-AES). We used the tree-rings of poplar from two different locations. The first one is in the area close to the power plant “Nikola Tesla” TENT A, Obrenovac, while the other one is in the urban area of Novi Sad. In almost all cases, samples from the location at Obrenovac registered elevated average concentrations of Fe, Hg, Mn, and Pb in the tree-rings of poplar.

  4. Real-time selective visual monitoring of Hg2+ detection at ppt level: An approach to lighting electrospun nanofibers using gold nanoclusters

    Science.gov (United States)

    Senthamizhan, Anitha; Celebioglu, Asli; Uyar, Tamer

    2015-05-01

    In this work, fluorescent gold nanocluster (AuNC) decorated polycaprolactone (PCL) nanofibers (AuNC*PCL-NF) for real time visual monitoring of Hg2+ detection at ppt level in water is demonstrated. The resultant AuNC*PCL-NF exhibiting remarkable stability more than four months at ambient environment and facilitates increased accessibility to active sites resulting in improved sensing performance with rapid response time. The fluorescence changes of AuNC*PCL-NF and their corresponding time dependent spectra, upon introduction of Hg2+, led to the visual identification of the sensor performance. It is observed that the effective removal of excess ligand (bovine serum albumin (BSA) greatly enhances the surface exposure of AuNC and therefore their selective sensing performance is achieved over competent metal ions such as Cu2+, Ni2+, Mn2+, Zn2+, Cd2+, and Pb2+ present in the water. An exceptional interaction is observed between AuNC and Hg2+, wherein the absence of excess interrupting ligand makes AuNC more selective towards Hg2+. The underlying mechanism is found to be due to the formation of Au-Hg amalgam, which was further investigated with XPS, TEM and elemental mapping studies. In short, our findings may lead to develop very efficient fluorescent-based nanofibrous mercury sensor, keeping in view of its stability, simplicity, reproducibility, and low cost.

  5. Interaction between mercury (Hg, arsenic (As and selenium (Se affects the activity of glutathione S-transferase in breast milk: possible relationship with fish and shellfish intake

    Directory of Open Access Journals (Sweden)

    Ramón Gaxiola-Robles

    2014-08-01

    Full Text Available Breast milk is regarded as an ideal source of nutrients for the growth and development of neonates, but it can also be a potential source of pollutants. Mothers can be exposed to different contaminants as a result of their lifestyle and environmental pollution. Mercury (Hg and arsenic (As could adversely affect the development of fetal and neonatal nervous system. Some fish and shellfish are rich in selenium (Se, an essential trace element that forms part of several enzymes related to the detoxification process, including glutathione S-transferase (GST. The goal of this study was to determine the interaction between Hg, As and Se and analyze its effect on the activity of GST in breast milk. Milk samples were collected from women between day 7 and 10 postpartum. The GST activity was determined spectrophotometrically; total Hg, As and Se concentrations were measured by atomic absorption spectrometry. To explain the possible association of Hg, As and Se concentrations with GST activity in breast milk, generalized linear models were constructed. The model explained 44% of the GST activity measured in breast milk. The GLM suggests that GST activity was positively correlated with Hg, As and Se concentrations. The activity of the enzyme was also explained by the frequency of consumption of marine fish and shellfish in the diet of the breastfeeding women.

  6. Electric dipole moments of superheavy elements

    CERN Document Server

    Radžiūtė, Laima; Jönsson, Per; Bieroń, Jacek

    2015-01-01

    The multiconfiguration Dirac-Hartree-Fock (MCDHF) method was employed to calculate atomic electric dipole moments (EDM) of the superheavy element copernicium (Cn, $Z=112$). The EDM enhancement factors of Cn, here calculated for the first time, are about one order of magnitude larger than those of Hg. The exponential dependence of enhancement factors on atomic number $Z$ along group 12 of the periodic table was derived from the EDMs of the entire homolog series, $^{69}_{30}$Zn, $^{111}_{\\phantom{1}48}$Cd, $^{199}_{\\phantom{1}80}$Hg, $^{285}_{112}$Cn, and $^{482}_{162}$Uhb. These results show that superheavy elements with sufficiently large half-lives are good candidates for EDM searches.

  7. Measurement of Linear Stark Interference in 199Hg

    CERN Document Server

    Loftus, T H; Griffith, W C; Romalis, M V; Heckel, B R; Fortson, E N

    2010-01-01

    We present measurements of Stark interference in the 6$^1S_0$ $\\rightarrow$ 6$^3P_1$ transition in $^{199}$Hg, a process whereby a static electric field $E$ mixes magnetic dipole and electric quadrupole couplings into an electric dipole transition, leading to $E$-linear energy shifts similar to those produced by a permanent atomic electric dipole moment (EDM). The measured interference amplitude, $a_{SI}$ = $(a_{M1} + a_{E2})$ = (5.8 $\\pm$ 1.5)$\\times 10^{-9}$ (kV/cm)$^{-1}$, agrees with relativistic, many-body predictions and confirms that earlier central-field estimates are a factor of 10 too large. More importantly, this study validates the capability of the $^{199}$Hg EDM search apparatus at the to resolve non-trivial, controlled, and sub-nHz Larmor frequency shifts with EDM-like characteristics.

  8. New features of superdeformed bands in 194Hg

    International Nuclear Information System (INIS)

    A striking difference between superdeformed (SD) nuclei near A = 190 and those in the other regions is the behavior of the dynamic moment of inertia (lm) with the rotational frequency hω. While the (lm) patterns of the SD bands near A = 130 and A = 150 show pronounced variations, the majority of the SD bands near A = 190 display the same large, smooth increase of (lm) within the frequency range 0.15 194Hg were populated with the reaction 150Nd(48Ca,4n) 194Hg at a beam energy of 206 MeV. The gamma rays emitted in the reaction were detected with the Gammasphere detector array (32 detectors for this experiment)

  9. Measurement of linear stark interference in 199Hg.

    Science.gov (United States)

    Loftus, T H; Swallows, M D; Griffith, W C; Romalis, M V; Heckel, B R; Fortson, E N

    2011-06-24

    We present measurements of Stark interference in the (61)S(0)→6(3)P(1) transition in (199)Hg, a process whereby a static electric field E mixes magnetic dipole and electric quadrupole couplings into an electric dipole transition, leading to E-linear energy shifts similar to those produced by a permanent atomic electric dipole moment (EDM). The measured interference amplitude, a(SI) = (a(M1) + a(E2)) = (5.8 ± 1.5) × 10(-9) (kV / cm)(-1), agrees with relativistic, many-body predictions and confirms that earlier central-field estimates are a factor of 10 too large. More importantly, this study validates the capability of the (199)Hg EDM search apparatus to resolve nontrivial, controlled, and sub-nHz Larmor frequency shifts with EDM-like characteristics. PMID:21770639

  10. Measurement of Linear Stark Interference in Hg199

    Science.gov (United States)

    Loftus, T. H.; Swallows, M. D.; Griffith, W. C.; Romalis, M. V.; Heckel, B. R.; Fortson, E. N.

    2011-06-01

    We present measurements of Stark interference in the 6S01→6P13 transition in Hg199, a process whereby a static electric field E mixes magnetic dipole and electric quadrupole couplings into an electric dipole transition, leading to E-linear energy shifts similar to those produced by a permanent atomic electric dipole moment (EDM). The measured interference amplitude, aSI=(aM1+aE2)=(5.8±1.5)×10-9(kV/cm)-1, agrees with relativistic, many-body predictions and confirms that earlier central-field estimates are a factor of 10 too large. More importantly, this study validates the capability of the Hg199 EDM search apparatus to resolve nontrivial, controlled, and sub-nHz Larmor frequency shifts with EDM-like characteristics.

  11. Hvordan understøttes hg-elevers kompetenceudvikling

    DEFF Research Database (Denmark)

    Svejgaard, Karin Løvenskjold; Hansen, Jens Ager; Karmark, Ole

    Publikationen handler om, hvordan hg-elever arbejder og dermed lærer og udvikler kvalifikationer og kompetencer i de undervisnings- og arbejdsformer, de indgår i. Indholdet er baseret på observationer af elever i klasseundervisning, gruppearbejde eller individuel arbejde i forlængelse af...... klasseundervisning og af elever i projektarbejde. Observationerne er gennemført på tre jyske handelsskoler....

  12. Gammastrahlung vom Einfang thermischer Neutronen in Hg 199

    DEFF Research Database (Denmark)

    Maier, B.P.; Gruber, U.; Koch, H. R.;

    1965-01-01

    103 gamma transitions in Hg 200 have been observed. 37 of them were fitted into a level scheme which comprises 17 states. The energy of the one-phonon vibrational stateI=2+ has been determined to be 367.970±0.020 keV, that of the two-phonon vibrational triplet 947.34±0.07 keV, 1029.37±0.05 keV an...

  13. Pulsed corona discharge for oxidation of gaseous elemental mercury - article no. 251503

    Energy Technology Data Exchange (ETDEWEB)

    Ko, K.B.; Byun, Y.; Cho, M.; Namkung, W.; Hamilton, I.P.; Shin, D.N.; Koh, D.J.; Kim, K.T. [Research Institute for Industrial Science & Technology, Pohang (Republic of Korea)

    2008-06-15

    Positive pulsed corona discharge has been applied for the oxidation of gaseous elemental mercury (Hg{sup O} from a simulated flue gas. The oxidation of Hg{sup 0} to Hg{sup O} and HgCl{sub 2} can significantly enhance the mercury removal from flue gas. At a gas condition of O{sub 2} (10%), H{sub 2}O (3%), and N{sub 2} (balance), Hg{sup 0} oxidation efficiency of 84% was achieved at an input energy density of 45 J/l. The presence of NO, however, hinders Hg{sup 0} oxidation due to the preferential reaction of NO with O and O{sub 3}. On the contrary, SO{sub 2} shows little effect on Hg{sup 0} oxidation due to its preferential reaction with OH. It has been also observed that the HCl in gas stream can be dissociated to Cl and Cl{sub 2} and can induce additional Hg{sup 0} oxidation to HgCl{sub 2}.

  14. Reduced trace element concentrations in fast-growing juvenile Atlantic salmon in natural streams

    OpenAIRE

    Ward, Darren M.; Keith H Nislow; Celia Y. Chen; Folt, Carol L

    2010-01-01

    To assess the effect of rapid individual growth on trace element concentrations in fish, we measured concentrations of seven trace elements (As, Cd, Cs, Hg, Pb, Se, Zn) in stream-dwelling Atlantic salmon (Salmo salar) from 15 sites encompassing a 10-fold range in salmon growth. All salmon were hatched under uniform conditions, released into streams, and sampled ~120 days later for trace element analysis. For most elements, element concentrations in salmon tracked those in their prey. Fast-gro...

  15. Dielectric properties of nanophase Ag2HgI4 and Ag2HgI4–Al2O3 nanocomposites

    Indian Academy of Sciences (India)

    S Sankara Narayanan Potty; M Abdul Khadar

    2000-10-01

    The dielectric properties of nanophase Ag2HgI4 and Ag2HgI4–Al2O3 nanocomposites at different frequencies have been studied over a temperature range covering the stability range of phase of Ag2HgI4 and beyond the to phase transition temperature. ', tan and a.c. of nanophase Ag2HgI4 and Ag2HgI4–Al2O3 nanocomposites were found to be larger than the reported values for polycrystalline pellets of Ag2HgI4 . The dielectric properties of the nanocomposites were found to be a function of the wt.% of nano alumina. The observed changes are attributed to the grain boundary properties of nanophase materials and to the microsize space charge effects.

  16. Crystal structure of the Hg{sub 4}SiS{sub 6} and Hg{sub 4}SiSe{sub 6} compounds

    Energy Technology Data Exchange (ETDEWEB)

    Gulay, L.D.; Olekseyuk, I.D.; Parasyuk, O.V

    2002-12-16

    The crystal structures of Hg{sub 4}SiS{sub 6} and Hg{sub 4}SiSe{sub 6} compounds were investigated using X-ray powder diffraction. These compounds crystallize in the monoclinic Cc space group with the lattice parameters a=1.23020(5), b=0.71031(4), c=1.22791(4) nm, {beta}=109.721(3) deg. for Hg{sub 4}SiS{sub 6} and a=1.28110(4), b=0.74034(4), c=1.27471(1) nm, {beta}=109.605(3) deg. for Hg{sub 4}SiSe{sub 6}. Atomic parameters were refined in the isotropic approximation (R{sub I}=0.0571 and R{sub I}=0.0555 for the Hg{sub 4}SiS{sub 6} and Hg{sub 4}SiSe{sub 6}, respectively)

  17. Investigation of 203,205Hg with the (d,pγ) reaction - identification of the i13/2 neutron hole state in 205Hg

    International Nuclear Information System (INIS)

    Low lying levels in 203Hg and 205Hg were studied with the (d, p) deuteron break-up reaction at Ed=14 and 18 MeV. Gamma-rays and conversion-electrons were measured in coincidence with protons. In addition delayed spectra were recorded with μs and ms beam pulsing. The i13/2 neutron hole state was identified in 205Hg and confirmed in 203Hg. The known level structure of 205Hg below 2 MeV is confirmed and extended. For 203Hg we observe the γ-decay of several levels below 1.5 MeV, which were previously known from transfer reactions. (orig.)

  18. Anthropogenic and geogenic Cd, Hg, Pb and Se sources of contamination in a brackish aquifer below agricultural fields

    Science.gov (United States)

    Mastrocicco, Micòl; Colombani, Nicolò; Di Giuseppe, Dario; Faccini, Barbara; Ferretti, Giacomo; Coltorti, Massimo

    2015-04-01

    Groundwater quality is often threatened by industrial, agricultural and land use practices (anthropogenic input). In deltaic areas is however difficult to distinguish between geogenic and anthropogenic inorganic contaminants pollution, since these phenomena can influence each other and often display a seasonal cycling. The effect of geogenic groundwater ionic strength (>10 g/l) on the mobility of trace elements like Cd, Hg, Pb and Se was studied in combination with the anthropogenic sources of these elements (fertilizers) in a shallow aquifer. The site is located in the Po river plain (Northern Italy) in an agricultural field belonging to a reclaimed deltaic environment, near Codigoro town. It is 6 ha wide and is drained by a subsurface drainage system made of PVC tile drains with a slope of 3‰, which provides gravity drainage towards two ditches that in turn discharge in a main channel. The whole area has been intensively cultivated with cereal rotation since 1960, mainly using synthetic urea as nitrogen fertilizer at an average rate of 180 kg-N/ha/y and pig slurry at an average rate of 60 kg-N/ha/y. The sediments were analyzed for major and trace elements via XRF, while major ions in groundwater were analyzed via IC and trace elements via ICP-MS. Three monitoring wells, with an inner diameter of 2 cm and screened down to 4 m below ground level, were set up in the field and sampled every four month from 2012 to 2014. The use of intensive depth profiles with resolution of 0.5 m in three different locations, gave insights into groundwater and sediment matrix interactions. To characterize the anthropogenic inputs synthetic urea and pig slurry were analyzed for trace elements via ICP-MS. The synthetic urea is a weak source of Cd and Hg (~1 ppb), while Se and Pb are found below detection limits. The pig slurry is a much stronger source of Se (~19 ppb) and Pb (~23 ppb) and a weak source of Cd (~3 ppb) and Hg (~2 ppb). Although, the mass loading rate pig slurry is

  19. A study on removal of elemental mercury in flue gas using fenton solution

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yangxian; Wang, Yan; Wang, Qian; Pan, Jianfeng [School of Energy and Power Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013 (China); Zhang, Yongchun [Jiangsu Province Special Equipment Safety Supervision Inspection Institute (Branch of Wuxi), Wuxi 214000 (China); Zhou, Jianfei [School of Energy and Power Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013 (China); Zhang, Jun [Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, Southeast University, Nanjing 210096 (China)

    2015-07-15

    Highlights: • A novel technique on oxidation of Hg{sup 0} using Fenton was proposed. • The effects of several process parameters on Hg{sup 0} removal were studied. • Products and ·OH in solution were detected. • Reaction mechanism of Hg{sup 0} removal was studied. • Simultaneous removal of Hg{sup 0}, NO and SO{sub 2} was also studied. - Abstract: A novel technique on oxidation-separation of elemental mercury (Hg{sup 0}) in flue gas using Fenton solution in a bubbling reactor was proposed. The effects of several process parameters (H{sub 2}O{sub 2} concentration, Hg{sup 0} inlet concentration, Fe{sup 2+} concentration, solution temperature, solution pH, gas flow) and several flue gas components (NO, SO{sub 2}, O{sub 2}, CO{sub 2}, inorganic ions and particulate matters on Hg{sup 0} removal were studied. The results indicate that H{sub 2}O{sub 2} concentration, Fe{sup 2+} concentration, solution pH and gas flow have great effects on Hg{sup 0} removal. Solution temperature, Hg{sup 0}, NO, SO{sub 2}, CO{sub 3}{sup 2−} and HCO{sub 3}{sup −} concentrations also have significant effects on Hg{sup 0} removal. However, Cl{sup −}, SO{sub 4}{sup 2−}, NO{sub 3}{sup −}, O{sub 2} and CO{sub 2} concentrations only have slight effects on Hg{sup 0} removal. Furthermore, reaction mechanism of Hg{sup 0} removal and simultaneous removal process of Hg{sup 0}, NO and SO{sub 2} were also studied. Hg{sup 0} is removed by oxidation of ·OH and oxidation of H{sub 2}O{sub 2}. The simultaneous removal efficiencies of 100% for SO{sub 2}, 100% for Hg{sup 0} and 88.3% for NO were obtained under optimal test conditions. The results demonstrated the feasibility of Hg{sup 0} removal and simultaneous removal of Hg{sup 0}, SO{sub 2} and NO using Fenton solution in a bubbling reactor.

  20. Analysis by neutron activation in moss samples for the determination of Cr, Se, As and Hg; Analisis por activacion neutronica en muestras de musgos para la determinacion de Cr, Se, As y Hg

    Energy Technology Data Exchange (ETDEWEB)

    Mejia C, R.; Garcia R, G. [Instituto Tecnologico de Toluca, Departamento de Posgrado, Av. Tecnologico s/n, Fraccionamiento La Virgen, 52149 Metepec, Estado de Mexico (Mexico); Lopez R, C.; Avila P, P.; Longoria G, L. C., E-mail: rosario.mejia@inin.gob.mx [ININ, Departamento del Reactor, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2012-10-15

    This research work, presents a study of environmental monitoring in the Metropolitan Area of Toluca Valley using as bio-monitors to the mosses (bryophytes) native of different sites, analyzing the concentrations of As, Cr, Hg and Se, present in its structure. The analysis technique used to identify and to quantify to these elements was the Analysis by Neutron Activation, a nuclear analytic technique that allowed determining the concentrations at track level for its great versatility. Likewise the morphological study of the bryophyte Leskea angustata is presented by scanning electron microscopy. (Author)

  1. 40 CFR 60.4141 - Timing requirements for Hg allowance allocations.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Timing requirements for Hg allowance... Times for Coal-Fired Electric Steam Generating Units Hg Allowance Allocations § 60.4141 Timing requirements for Hg allowance allocations. (a) By November 17, 2006, the permitting authority will submit...

  2. 40 CFR 60.4123 - Hg budget permit contents and term.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Hg budget permit contents and term. 60... Coal-Fired Electric Steam Generating Units Permits § 60.4123 Hg budget permit contents and term. (a) Each Hg Budget permit will contain, in a format prescribed by the permitting authority, all...

  3. 46 CFR 53.01-10 - Service restrictions and exceptions (replaces HG-101).

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Service restrictions and exceptions (replaces HG-101... ENGINEERING HEATING BOILERS General Requirements § 53.01-10 Service restrictions and exceptions (replaces HG... lieu of the requirements in HG-101 of section IV of the ASME Boiler and Pressure Vessel...

  4. 40 CFR 60.4120 - General Hg budget trading program permit requirements.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false General Hg budget trading program... and Compliance Times for Coal-Fired Electric Steam Generating Units Permits § 60.4120 General Hg budget trading program permit requirements. (a) For each Hg Budget source required to have a title...

  5. 48 CFR 752.231-71 - Salary supplements for HG employees.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Salary supplements for HG....231-71 Salary supplements for HG employees. As prescribed in 731.205-71, for use in all contracts with a possible need or services of a HG employee. The clause should also be inserted in all...

  6. 40 CFR 60.4152 - Responsibilities of Hg authorized account representative.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Responsibilities of Hg authorized... and Compliance Times for Coal-Fired Electric Steam Generating Units Hg Allowance Tracking System § 60.4152 Responsibilities of Hg authorized account representative. Following the establishment of a...

  7. Discrimination of two geographically distinct populations of sea bass Dicentrarchus labrax, using stable isotopic signatures of mercury (δ202Hg, Δ199Hg)

    OpenAIRE

    Cransveld, Alice; Amouroux, David; Koutrakis, Emmanuil; Bérail, Sylvain; Caiyan, Feng; Barre, Julien P. G.; Schnitzler, Joseph; Das, Krishna

    2014-01-01

    Despite the reduction of mercury (Hg) emissions in Europe in the last decades, Hg emissions are increasing worldwide and concentrations found in some marine predators remain high. This raises questions on mercury's biogeochemical cycle at both local and global scale. In the present work, we investigate the possibility to use mercury isotopic signature in fish as a tool to discriminate different polluted areas and potential pollution sources. Indeed, Hg can exhibit both mass-dependent (MDF) an...

  8. Impacts of forest harvesting on mobilization of Hg and MeHg in drained peatland forests on black schist or felsic bedrock.

    Science.gov (United States)

    Ukonmaanaho, Liisa; Starr, Mike; Kantola, Marjatta; Laurén, Ari; Piispanen, Juha; Pietilä, Heidi; Perämäki, Paavo; Merilä, Päivi; Fritze, Hannu; Tuomivirta, Tero; Heikkinen, Juha; Mäkinen, Jari; Nieminen, Tiina M

    2016-04-01

    Forest harvesting, especially when intensified harvesting method as whole-tree harvesting with stump lifting (WTHs) are used, may increase mercury (Hg) and methylmercury (MeHg) leaching to recipient water courses. The effect can be enhanced if the underlying bedrock and overburden soil contain Hg. The impact of stem-only harvesting (SOH) and WTHs on the concentrations of Hg and MeHg as well as several other variables in the ditch water was studied using a paired catchment approach in eight drained peatland-dominated catchments in Finland (2008-2012). Four of the catchments were on felsic bedrock and four on black schist bedrock containing heavy metals. Although both Hg and MeHg concentrations increased after harvesting in all treated sites according to the randomized intervention analyses (RIAs), there was only a weak indication of a harvest-induced mobilization of Hg and MeHg into the ditches. Furthermore, no clear differences between WTHs and SOH were found, although MeHg showed a nearly significant difference (p = 0.06) between the harvesting regimes. However, there was a clear bedrock effect, since the MeHg concentrations in the ditch water were higher at catchments on black schist than at those on felsic bedrock. The pH, suspended solid matter (SSM), dissolved organic carbon (DOC), and iron (Fe) concentrations increased after harvest while the sulfate (SO4-S) concentration decreased. The highest abundances of sulfate-reducing bacteria (SRB) were found on the sites with high MeHg concentrations. The biggest changes in ditch water concentrations occurred first 2 years after harvesting. PMID:26979172

  9. Analysis of HgI2 and PbI2 crystals and detectors by particle-induced x-ray emission (PIXE) and ion backscattering spectroscopy (IBS)

    International Nuclear Information System (INIS)

    The Ion Micro-Analysis Group (IMAG) in Livermore conducts quantitative trace elemental analysis with PIXE and depth profiling with IBS using an MeV ion microbeam. The system has the capability to produce two-dimensional trace element and IBS images. PIXE analyses have been conducted on HgI2 and PbI2 crystals and detector materials in order to identify and quantify near surface trace contaminants. IBS measurements have been conducted to investigate elemental depth distributions in various materials. The results of measurements on several different samples are reported and a discussion of factors affecting quantitative in vacuo microanalysis of these materials is presented

  10. A comparative study on surface morphology from the HgI{sub 2} semiconductors prepared by different techniques

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Joao F.T.; Ferraz, Caue de M.; Santos, Robinson A. dos; Mesquita, Carlos H. de; Hamada, Margarida M., E-mail: mmhamada@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    The impurity effect in the surface morphology quality of HgI{sub 2} crystals was evaluated, aiming a future application of these crystals as room temperature radiation semiconductor detector. The crystals were purified and grown by two techniques: (1) physical vapor transport (PVT) and (2) saturated solution from dimethylsulfoxide (DMSO) complexes. Systematic measurements were carried out for determining the stoichiometry, structure orientation, surface morphology and impurity of the crystal. The best quality of surface morphology was found for the crystals purified and grown by the PVT technique. Significant decrease in the impurity concentration was found, purifying the crystal by means of two successive growths by the PVT technique, while a Si contamination in the HgI{sub 2} crystal was observed, during its growth by the DMSO method. Thus, for DMSO technique was not possible to identify the peaks of the other trace elements present as impurities in the PVT crystal, due to the high intensity of the Si peak in the DMSO crystal. It was demonstrated the impurities affect significantly the surface morphology quality from the HgI{sub 2} crystal. Key Words: Semiconductor crystal, Radiation detector, Mercury Iodide crystal, surface morphology. (author)

  11. Investigation of MIS structures with high specific capacitance in InSb and HgCdTe semiconductors

    International Nuclear Information System (INIS)

    Electrophysical properties of metall-insulator-semiconductor (MIS) structures with high capacitance per unit area based on InSb and HgCdTe have been investigated. Ta2O5, Nb2O5 and TiO2 dielectric films have been deposited by the reactive magnetron sputtering on CdHgTe with anodic sulfide films (10-20 nm) and on InSb with anodic oxide films (10-25 nm). MIS-elements with capacitance (2,5-4,0) x 10-7 F x cm-2 at 293 K and 2 x 10-7 F x cm-2 at 77 K were made. For MIS-structures with Nb2O5 film as dielectric surface the state density was 1 x 1011 eV-1 x cm-2 for HgCdTe and 5 x 1011 eV-1 x cm-2 for InSb. 10 refs.; 2 figs.; 2 tabs

  12. Supramolecular aggregation of Ni(salen) with (C6F5)2Hg and [o-C6F4Hg]3.

    Science.gov (United States)

    Tsunoda, Mitsukimi; Fleischmann, Martin; Jones, J Stuart; Bhuvanesh, Nattamai; Scheer, Manfred; Gabbaï, François P

    2016-03-15

    As part of our ongoing interest in the supramolecular chemistry of fluorinated organomercurials, we have investigated the interaction of bis(pentafluorophenyl)mercury ((C6F5)2Hg), and trimeric (perfluoro-o-phenylene)mercury ([o-C6F4Hg]3), with nickel(ii) N,N'-bis(salicylidene)ethylenediamine) (Ni(salen)). While solution studies monitored by UV-VIS spectroscopy suggest that Ni(salen) interacts with the trinuclear mercury complex in solution, the 1 : 1 adduct (Ni(salen)-(C6F5)2Hg) and the 1 : 1 adducts Ni(salen)-[o-C6F4Hg]3 and [Ni(salen)-[o-C6F4Hg]3-THF-H2O] can be obtained by slow evaporation of solutions containing the two building blocks. While arene-fluoroarene and hydrogen bonding interactions, as well as interactions between mercury and the salen ligand are the predominant forces responsible for the formation of these adducts, Ni(salen)-[o-C6F4Hg]3 and [Ni(salen)-[o-C6F4Hg]3-THF-H2O] also display short Ni-Hg separations consistent with the presence of metallophilic interactions. Quantum theory of atoms in molecules (QTAIM) analyses of the Ni-Hg interactions in these adducts finds that these interactions are dominated by electrostatic and dispersion forces, despite featuring non-negligible covalent contributions. PMID:26865181

  13. Phase transitions involving vacancy ordering in two metal mercuric iodides, Ag2HgI4 and Cu2HgI4

    Science.gov (United States)

    Lumsden, Mark; Steinitz, Michael; McAlduff, E. J.

    1995-06-01

    We have investigated the thermochromic order-disorder phase transitions in two superionic conducting compounds, Ag2HgI4 and Cu2HgI4, using capacitance dilatometry to determine the relative volume change, ΔV/V, at the transitions. We find an average ΔV/V of 9.6×10-3 for Ag2HgI4 at a transition temperature of 48.75 °C and an average ΔV/V of 4.0×10-3 for Cu2HgI4 at a transition temperature of 63 °C.

  14. Concentrations of 17 elements, including mercury, in the tissues, food and abiotic environment of Arctic shorebirds

    International Nuclear Information System (INIS)

    Exposure to contaminants is one hypothesis proposed to explain the global decline in shorebirds, and is also an increasing concern in the Arctic. We assessed potential contaminants (As, Be, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Sb, Se, Tl, V, and Zn) at a shorebird breeding site in Nunavut, Canada. We compared element levels in soil, invertebrates and shorebird blood to assess evidence for bioconcentration and biomagnification within the Arctic-based food chain. We tested whether elements in blood, feathers and eggs of six shorebird species (Pluvialis squatarola, Calidris alpina, C. fuscicollis, Phalaropus fulicarius, Charadrius semipalmatus, and Arenaria interpres) were related to fitness endpoints: adult body condition, blood-parasite load, egg size, eggshell thickness, nest duration, and hatching success. To facilitate comparison to other sites, we summarise the published data on toxic metals in shorebird blood and egg contents. Element concentrations and invertebrate composition differed strongly among habitats, and habitat use and element concentrations differed among shorebird species. Hg, Se, Cd, Cu, and Zn bioconcentrated from soil to invertebrates, and Hg, Se and Fe biomagnified from invertebrates to shorebird blood. As, Ni, Pb, Co and Mn showed significant biodilution from soil to invertebrates to shorebirds. Soil element levels were within Canadian guidelines, and invertebrate Hg levels were below dietary levels suggested for the protection of wildlife. However, maximum Hg in blood and eggs approached levels associated with toxicological effects and Hg-pollution in other bird species. Parental blood-Hg was negatively related to egg volume, although the relationship varied among species. No other elements approached established toxicological thresholds. In conclusion, whereas we found little evidence that exposure to elements at this site is leading to the declines of the species studied, Hg, as found elsewhere in the Canadian Arctic, is of potential

  15. Magneto-optical transitions between subbands with different quantum numbers in narrow gap HgTe-CdTe superlattices

    Science.gov (United States)

    Luo, H.; Yang, G. L.; Furdyna, J. K.; Ram-Mohan, L. R.

    1991-10-01

    Magneto-optical transitions induced by the coupling between the conduction and the valence bands through the momentum matrix element, and by the coupling terms between light and heavy holes resulting from an applied magnetic field are studied theoretically in narrow gap HgTe-CdTe superlattices. Selection rules and transition probabilities for the above transitions are presented and compared with allowed transitions. The numerical results for the transition probabilities show that some of the interband transitions with ΔN=±1 are significant and have to be considered in the studies of interband magneto-optical spectra of narrow gap superlattices.

  16. Concentration of stable elements in food products

    Energy Technology Data Exchange (ETDEWEB)

    Montford, M.A.; Shank, K.E.; Hendricks, C.; Oakes, T.W.

    1980-01-01

    Food samples were taken from commercial markets and analyzed for stable element content. The concentrations of most stable elements (Ag, Al, As, Au, Ba, Br, Ca, Ce, Cl, Co, Cr, Cs, Cu, Fe, Hf, I, K, La, Mg, Mn, Mo, Na, Rb, Sb, Sc, Se, Sr, Ta, Th, Ti, V, Zn, Zr) were determined using multiple-element neutron activation analysis, while the concentrations of other elements (Cd, Hg, Ni, Pb) were determined using atomic absorption. The relevance of the concentrations found are noted in relation to other literature values. An earlier study was extended to include the determination of the concentration of stable elements in home-grown products in the vicinity of the Oak Ridge National Laboratory. Comparisons between the commercial and local food-stuff values are discussed.

  17. Concentration of stable elements in food products

    International Nuclear Information System (INIS)

    Food samples were taken from commercial markets and analyzed for stable element content. The concentrations of most stable elements (Ag, Al, As, Au, Ba, Br, Ca, Ce, Cl, Co, Cr, Cs, Cu, Fe, Hf, I, K, La, Mg, Mn, Mo, Na, Rb, Sb, Sc, Se, Sr, Ta, Th, Ti, V, Zn, Zr) were determined using multiple-element neutron activation analysis, while the concentrations of other elements (Cd, Hg, Ni, Pb) were determined using atomic absorption. The relevance of the concentrations found are noted in relation to other literature values. An earlier study was extended to include the determination of the concentration of stable elements in home-grown products in the vicinity of the Oak Ridge National Laboratory. Comparisons between the commercial and local food-stuff values are discussed

  18. Strontium metallides along the section SrIn{sub 4} - SrHg{sub 4}; Strontium-Metallide im Bereich des Schnitts SrIn{sub 4} - SrHg{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Wendorff, Marco; Roehr, Caroline [Freiburg Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie

    2014-04-15

    In a combined synthetic, X-ray single-crystal and bond-theoretical study the phase widths of SrIn{sub 4} and the related Sr{sub 3}In{sub 11} upon a successive substitution of indium against the more electron-poor, more electronegative and only slightly smaller element mercury have been studied. Along the 1:4 section Sr(In{sub 1-x}Hg{sub x}){sub 4} the monoclinic structure of SrIn{sub 4} (EuIn{sub 4}-type structure) is stable up to x = 0.14(1) (SrIn{sub 3.44}Hg{sub 0.56}: monoclinic, C2/m, a = 1208.3(6), b = 502.5(2), c = 997.7(6) pm, β = 115.16(3) , Z = 4, R1 = 0.0324). Further increased mercury content results in a distinct stability region of the very common BaAl{sub 4} structure type (tetragonal, I4/mmm, Z = 2), which starts at x = 0.241(7) (SrIn{sub 3.04}Hg{sub 0.96}: a = 469.4(2), c = 1246.4(7) pm, R1 = 0.0374) and reaches up to the fully ordered compound SrIn{sub 2}Hg{sub 2} (x = 0.5: a = 456.4(3), c = 1273.5(11) pm, R1 = 0.0572). Unexpectedly, in the small composition range from x = 0.68(1) to 0.758(6) (SrIn{sub 1.16}Hg{sub 2.84}: a = 1178.5(4), b = 495.20(12), c = 1016.8(4) pm, β = 119.67(2) , R1 = 0.0542; SrIn{sub 0.97}Hg{sub 3.03}: a = 1167.30(4), b = 495.32(2), c = 1018.50(3) pm, β = 119.657(2) , R1 = 0.0426) the EuIn{sub 4} structure type exhibits a further small stability range. The structures of the two slightly different In- and Hg-rich variants of the EuIn{sub 4} type are described and compared, indicating the similarities to the KHg{sub 2} (layers of folded In/Hg ladders) and the BaAl{sub 4} (flat square pyramids) structure types as well as to the structure of elemental mercury (rhombohedra). From samples of an intermediate In/Hg ratio (e.g. x = 0.55), the new 1:3 compound SrIn{sub 1.2}Hg{sub 1.8} (monoclinic, C2/m, a = 1168.5(13), b = 497.0(4), c = 1471(2) pm, β = 92.07(10) , Z = 8, R1 = 0.0818) is formed. It crystallizes in a new structure type, which - according to the compound's composition - can be described as a stacking variant of

  19. Manila clams from Hg polluted sediments of Marano and Grado lagoons (Italy) harbor detoxifying Hg resistant bacteria in soft tissues

    International Nuclear Information System (INIS)

    A mechanism of mercury detoxification has been suggested by a previous study on Hg bioaccumulation in Manila clams (Ruditapes philippinarum) in the polluted Marano and Grado lagoons and in this study we demonstrate that this event could be partly related to the detoxifying activities of Hg-resistant bacteria (MRB) harbored in clam soft tissues. Therefore, natural clams were collected in six stations during two different periods (winter and spring) from Marano and Grado Lagoons. Siphons, gills and hepatopancreas from acclimatized clams were sterile dissected to isolate MRB. These anatomical parts were glass homogenized or used for whole, and they were lying on a solid medium containing 5 mg l−1 HgCl2 and incubated at 30 °C. A total of fourteen bacterial strains were isolated and were identified by 16S rDNA sequencing and analysis, revealing that strains were representative of eight bacterial genera, four of which were Gram-positive (Enterococcus, Bacillus, Jeotgalicoccus and Staphylococcus) and other four were Gram-negative (Stenotrophomonas, Vibrio, Raoultella and Enterobacter). Plasmids and merA genes were found and their sequences determined. Fluorescence in situ hybridization (FISH) technique shows the presence of Firmicutes, Actinobacteria and Gammaproteobacteria by using different molecular probes in siphon and gills. Bacterial clumps inside clam flesh were observed and even a Gram-negative endosymbiont was disclosed by transmission electronic microscope inside clam cells. Bacteria harbored in cavities of soft tissue have mercury detoxifying activity. This feature was confirmed by the determination of mercuric reductase in glass-homogenized siphons and gills. -- Highlights: ► We isolated Gram-positive and Gram-negative Hg resistant strains from soft tissues of Ruditapes philippinarum. ► We identify 14 mercury resistant strains by 16S rRNA gene sequences. ► Bacteria in siphon and gill tissues of clams were observed by TEM and identified with different

  20. Manila clams from Hg polluted sediments of Marano and Grado lagoons (Italy) harbor detoxifying Hg resistant bacteria in soft tissues

    Energy Technology Data Exchange (ETDEWEB)

    Baldi, Franco, E-mail: baldi@unive.it [Dipartimento di Scienze Molecolari e Nanosistemi, Cà Foscari University of Venice, Dorsoduro 2137, 30123 Venice (Italy); Gallo, Michele; Marchetto, Davide [Dipartimento di Scienze Molecolari e Nanosistemi, Cà Foscari University of Venice, Dorsoduro 2137, 30123 Venice (Italy); Faleri, Claudia [Department of Environmental Science ‘G. Sarfatti’, University of Siena, 53100 Siena (Italy); Maida, Isabel; Fani, Renato [Dipartimento di Biologia Evoluzionistica, Via Romana, 17, University of Florence, 50125 Florence (Italy)

    2013-08-15

    A mechanism of mercury detoxification has been suggested by a previous study on Hg bioaccumulation in Manila clams (Ruditapes philippinarum) in the polluted Marano and Grado lagoons and in this study we demonstrate that this event could be partly related to the detoxifying activities of Hg-resistant bacteria (MRB) harbored in clam soft tissues. Therefore, natural clams were collected in six stations during two different periods (winter and spring) from Marano and Grado Lagoons. Siphons, gills and hepatopancreas from acclimatized clams were sterile dissected to isolate MRB. These anatomical parts were glass homogenized or used for whole, and they were lying on a solid medium containing 5 mg l{sup −1} HgCl{sub 2} and incubated at 30 °C. A total of fourteen bacterial strains were isolated and were identified by 16S rDNA sequencing and analysis, revealing that strains were representative of eight bacterial genera, four of which were Gram-positive (Enterococcus, Bacillus, Jeotgalicoccus and Staphylococcus) and other four were Gram-negative (Stenotrophomonas, Vibrio, Raoultella and Enterobacter). Plasmids and merA genes were found and their sequences determined. Fluorescence in situ hybridization (FISH) technique shows the presence of Firmicutes, Actinobacteria and Gammaproteobacteria by using different molecular probes in siphon and gills. Bacterial clumps inside clam flesh were observed and even a Gram-negative endosymbiont was disclosed by transmission electronic microscope inside clam cells. Bacteria harbored in cavities of soft tissue have mercury detoxifying activity. This feature was confirmed by the determination of mercuric reductase in glass-homogenized siphons and gills. -- Highlights: ► We isolated Gram-positive and Gram-negative Hg resistant strains from soft tissues of Ruditapes philippinarum. ► We identify 14 mercury resistant strains by 16S rRNA gene sequences. ► Bacteria in siphon and gill tissues of clams were observed by TEM and identified

  1. 203Hg binding in the liver and kidney of the frog, Rana tigrina

    International Nuclear Information System (INIS)

    Following a single i.p. dose of the radioisotope, 203Hg was found to accumulate in both the high and low molecular weight (MW) fractions of the kidney and liver of the frog. The course of 203Hg appearance in the 2 fractions varied in the liver; 203Hg was exclusively associated with the higher MW fractions at 2 days whereas the radiotracer appeared in both low and high MW fractions at 4 and 7 days after administration. In the kidneys, however, 203Hg was associated with high and low MW fractions at all the intervals studied. Low MW 203Hg binding fraction appeared to be a metallothionein-like substance. (Auth.)

  2. Lifetime measurements of yrast and excited superdeformed bands in 192,193Hg

    International Nuclear Information System (INIS)

    Quadrupole moments of the six known superdeformed (SD) bands of 193Hg and the yrast SD band of 192Hg have been determined by a Doppler-shift-attenuation-method measurement utilizing the gammasphere array. The quadrupole moments of all 193Hg SD bands were found to be similar, suggesting the active single-particle orbitals in the mass-190 region exhibit only small shape-driving effects. Additionally, there is evidence for an unexpected difference in the quadrupole moments of SD bands in 192Hg and 193Hg. copyright 1998 The American Physical Society

  3. Synthesis and growth of HgI2 nanocrystals in a glass matrix: Heat treatment

    International Nuclear Information System (INIS)

    Mercury iodide (HgI2) nanocrystals (NCs) were successfully grown in a barium phosphate glass matrix synthesized by fusion. Growth control of HgI2 NCs was investigated by Atomic Force Microscopy (AFM), Optical Absorption (OA), Fluorescence (FL), and X-ray diffraction (XRD). AFM images reveal the formation of HgI2 nanocrystals in host glass matrix. HgI2 NCs growth was evidenced by an OA and FL band red-shift with increasing annealing time. XRD measurements revealed the β crystalline phase of the HgI2 nanocrystals

  4. Two new reversible naphthalimide-based fluorescent chemosensors for Hg(2.).

    Science.gov (United States)

    Li, Gongchun; Gao, Guangqin; Cheng, Junye; Chen, Xiaopo; Zhao, Yufen; Ye, Yong

    2016-06-01

    Naphthalimide-based fluorescent probes 1 and 2 were synthesized, and were designed to form probe-Hg complexes through Hg(2+) ions coordinated to the amide group and imidazole group. They showed high sensitivity and were selective 'naked-eye' chemosensors for Hg(2+) in phosphate buffer. The fluorescence of compounds 1 and 2 could be quenched up to 90% by the addition of Hg(2+) . Reversible probes can detect Hg(2+) ions over a wide pH range (7.0-10.0). Copyright © 2015 John Wiley & Sons, Ltd. PMID:26592959

  5. Trend and characteristics of atmospheric emissions of Hg, As, and Se from coal combustion in China, 1980-2007

    Science.gov (United States)

    Tian, H. Z.; Wang, Y.; Xue, Z. G.; Cheng, K.; Qu, Y. P.; Chai, F. H.; Hao, J. M.

    2010-12-01

    Emissions of hazardous trace elements in China are of great concern because of their negative impacts on local air quality as well as on regional environmental health and ecosystem risks. In this paper, the atmospheric emissions of mercury (Hg), arsenic (As), and selenium (Se) from coal combustion in China for the period 1980-2007 are estimated on the basis of coal consumption data and emission factors, which are specified by different categories of combustion facilities, coal types, and the equipped air pollution control devices configuration (Dust collectors, FGD, etc.). Specifically, multi-year emission inventories of Hg, As, and Se from 30 provinces and 4 economic sectors (thermal power, industry, residential use, and others) are evaluated and analyzed in detail. Furthermore, the gridded distribution of provincial-based Hg, As, and Se emissions in 2005 at a resolution of 1° × 1° is also plotted. It shows that the calculated national total atmospheric emissions of Hg, As, and Se from coal combustion have rapidly increased from 73.59 t, 635.57 t, and 639.69 t in 1980 to 305.95 t, 2205.50 t, and 2352.97 t in 2007, at an annually averaged growth rate of 5.4%, 4.7%, and 4.9%, respectively. The industrial sector is the largest source for Hg, As, and Se, accounting for about 50.8%, 61.2%, and 56.2% of the national totals, respectively. The share of power plants is 43.3% for mercury, 24.9% for arsenic, and 33.4% for selenium, respectively. Also, it shows remarkably different regional contribution characteristics of these 3 types of trace elements, the top 5 provinces with the heaviest mercury emissions in 2007 are Shandong (34.40 t), Henan (33.63 t), Shanxi (21.14 t), Guizhou (19.48 t), and Hebei (19.35 t); the top 5 provinces with the heaviest arsenic emissions in 2007 are Shandong (219.24 t), Hunan (213.20 t), Jilin (141.21 t), Hebei (138.54 t), and Inner Mongolia (127.49 t); while the top 5 provinces with the heaviest selenium emissions in 2007 are Shandong (289

  6. Trend and characteristics of atmospheric emissions of Hg, As, and Se from coal combustion in China, 1980–2007

    Directory of Open Access Journals (Sweden)

    H. Z. Tian

    2010-09-01

    Full Text Available Emissions of hazardous trace elements in China are of great concern because of their negative impacts on local air quality as well as on regional environmental health and ecosystem risks. In this paper, the atmospheric emissions of mercury (Hg, arsenic (As, and selenium (Se from coal combustion in China for the period 1980–2007 are estimated on the basis of coal consumption data and emission factors, which are specified by different categories of combustion facilities, coal types, and the equipped air pollution control devices configuration (Dust collectors, FGD, etc.. Specifically, multi-year emission inventories of Hg, As, and Se from 30 provinces and 4 economic sectors (thermal power, industry, residential use, and others are evaluated and analyzed in detail. Furthermore, the gridded distribution of provincial-based Hg, As, and Se emissions in 2005 at a resolution of 1°×1° is also plotted. It shows that the calculated national total atmospheric emissions of Hg, As, and Se from coal combustion have rapidly increased from 73.59 t, 635.57 t, and 639.69 t in 1980 to 305.95 t, 2205.50 t, and 2352.97 t in 2007, at an annually averaged growth rate of 5.4%, 4.7%, and 4.9%, respectively. The industrial sector is the largest source for Hg, As, and Se, accounting for about 50.8%, 61.2%, and 56.2% of the national totals, respectively. The share of power plants is 43.3% for mercury, 24.9% for arsenic, and 33.4% for selenium, respectively. Also, it shows remarkably different regional contribution characteristics of these 3 types of trace elements, the top 5 provinces with the heaviest mercury emissions in 2007 are Shandong (34.40 t, Henan (33.63 t, Shanxi (21.14 t, Guizhou (19.48 t, and Hebei (19.35 t; the top 5 provinces with the heaviest arsenic emissions in 2007 are Shandong (219.24 t, Hunan (213.20 t, Jilin (141.21 t, Hebei (138.54 t, and Inner Mongolia (127.49 t; while the top 5 provinces with the heaviest selenium emissions in 2007 are Shandong

  7. Elemental Mercury Diffusion Processes and Concentration at the Lunar Poles

    Science.gov (United States)

    Moxley, Frederick; Killen, Rosemary M.; Hurley, Dana M.

    2011-01-01

    In 2009, the Lyman Alpha Mapping Project (LAMP) spectrograph onboard the Lunar Reconnaissance Orbiter (LRO) spacecraft made the first detection of element mercury (Hg) vapor in the lunar exosphere after the Lunar Crater Observing and Sensing Satellite (LCROSS) Centaur rocket impacted into the Cabeus crater in the southern polar region of the Moon. The lunar regolith core samples from the Apollo missions determined that Hg had a devolatilized pattern with a concentration gradient increasing with depth, in addition to a layered pattern suggesting multiple episodes of burial and volatile loss. Hg migration on the lunar surface resulted in cold trapping at the poles. We have modeled the rate at which indigenous Hg is lost from the regolith through diffusion out of lunar grains. We secondly modeled the migration of Hg vapor in the exosphere and estimated the rate of cold-trapping at the poles using a Monte Carlo technique. The Hg vapor may be lost from the exosphere via ionization, Jeans escape, or re-impact into the surface causing reabsorption.

  8. Mercury methylation in paddy soil: source and distribution of mercury species at a Hg mining area, Guizhou Province, China

    Science.gov (United States)

    Zhao, Lei; Anderson, Christopher W. N.; Qiu, Guangle; Meng, Bo; Wang, Dingyong; Feng, Xinbin

    2016-04-01

    Rice paddy plantation is the dominant agricultural land use throughout Asia. Rice paddy fields have been identified as important sites for methylmercury (MeHg) production in the terrestrial ecosystem and a primary pathway of MeHg exposure to humans in mercury (Hg) mining areas. We compared the source and distribution of Hg species in different compartments of the rice paddy during a complete rice-growing season at two different typical Hg-contaminated mining sites in Guizhou province, China: an abandoned site with a high Hg concentration in soil but a low concentration in the atmosphere and a current-day artisanal site with a low concentration in soil but a high concentration in the atmosphere. Our results showed that the flux of new Hg to the ecosystem from irrigation and atmospheric deposition was insignificant relative to the pool of old Hg in soil; the dominant source of MeHg to paddy soil is in situ methylation of inorganic Hg (IHg). Elevated MeHg concentrations and the high proportion of Hg as MeHg in paddy water and the surface soil layer at the artisanal site demonstrated active Hg methylation at this site only. We propose that the in situ production of MeHg in paddy water and surface soil is dependent on elevated Hg in the atmosphere and the consequential deposition of new Hg into a low-pH anoxic geochemical system. The absence of depth-dependent variability in the MeHg concentration in soil cores collected from the abandoned Hg mining site, consistent with the low concentration of Hg in the atmosphere and high pH of the paddy water and irrigation water, suggested that net production of MeHg at this site was limited. We propose that the concentration of Hg in ambient air is an indicator for the risk of MeHg accumulation in paddy rice.

  9. Au(n)Hg(m) clusters: mercury aurides, gold amalgams, or van der Waals aggregates?

    Science.gov (United States)

    Zaleski-Ejgierd, Patryk; Pyykkö, Pekka

    2009-11-12

    The class of bimetallic clusters, Au(n)M(m) (M = Zn, Cd, Hg), is calculated at the ab initio level using the DFT, RI-MP2, and CCSD(T) methods. For the triatomic Au2M (M = Zn, Cd), the auride-type linear Au-M-Au structures are preferred; for Au2Hg, the linear Au-Au-Hg "amalgam" is preferred. The mixed cation [HgAuHg]+, an analog of the known solid-state species Hg32+, is predicted. For larger Au(n)Hg(m) clusters, the results are similar to the isoelectronic Au(n)M- anions. Several local minima and transition states are identified. All are found to be planar. PMID:19228004

  10. A density functional theory study of the adsorption of Hg and HgCl2 on a CaO(001) surface

    Institute of Scientific and Technical Information of China (English)

    GUO Xin; ZHENG Chuguang; LU Nanxia

    2007-01-01

    The adsorption of mercury and mercury chloride on a CaO(001) surface was investigated by the density functional theory (DFT) by using Ca9O9 cluster embedded in an electrostatic field represented by 178 point charges at the crystal CaO lattice positions.For the mercury molecular axis normal to the surface,the mercury can only coordinate to the O2- anion and has a very weak binding energy of 19.649 kJ/mol.When the mercury chloride molecular axis is vertical to the surface,the Cl atom coordinates to the Ca2+ cation and has a binding energy of 23.699 kJ/mol.When the mercury chloride molecular axis is parallel to the surface,the Hg atom coordinates to the O2- anion and has a binding energy of 87.829 kJ/mol,which means that the parallel geometry is more stable than the vertical one.The present calculations show that CaO injection could substantially reduce gaseous mercury chloride,but have no apparent effect on the mercury,which is compatible with the available experimental results.This research will provide valuable information for optimizing and selecting a sorbent for the trace element in flue gas.

  11. Global observations and modeling of atmosphere-surface exchange of elemental mercury: a critical review

    Science.gov (United States)

    Zhu, Wei; Lin, Che-Jen; Wang, Xun; Sommar, Jonas; Fu, Xuewu; Feng, Xinbin

    2016-04-01

    Reliable quantification of air-surface fluxes of elemental Hg vapor (Hg0) is crucial for understanding mercury (Hg) global biogeochemical cycles. There have been extensive measurements and modeling efforts devoted to estimating the exchange fluxes between the atmosphere and various surfaces (e.g., soil, canopies, water, snow, etc.) in the past three decades. However, large uncertainties remain due to the complexity of Hg0 bidirectional exchange, limitations of flux quantification techniques and challenges in model parameterization. In this study, we provide a critical review on the state of science in the atmosphere-surface exchange of Hg0. Specifically, the advancement of flux quantification techniques, mechanisms in driving the air-surface Hg exchange and modeling efforts are presented. Due to the semi-volatile nature of Hg0 and redox transformation of Hg in environmental media, Hg deposition and evasion are influenced by multiple environmental variables including seasonality, vegetative coverage and its life cycle, temperature, light, moisture, atmospheric turbulence and the presence of reactants (e.g., O3, radicals, etc.). However, the effects of these processes on flux have not been fundamentally and quantitatively determined, which limits the accuracy of flux modeling. We compile an up-to-date global observational flux database and discuss the implication of flux data on the global Hg budget. Mean Hg0 fluxes obtained by micrometeorological measurements do not appear to be significantly greater than the fluxes measured by dynamic flux chamber methods over unpolluted surfaces (p = 0.16, one-tailed, Mann-Whitney U test). The spatiotemporal coverage of existing Hg0 flux measurements is highly heterogeneous with large data gaps existing in multiple continents (Africa, South Asia, Middle East, South America and Australia). The magnitude of the evasion flux is strongly enhanced by human activities, particularly at contaminated sites. Hg0 flux observations in East

  12. Interaction properties of ytterbium with elements of Mendeleev periodic table

    International Nuclear Information System (INIS)

    This article presents the new data on ytterbium interaction with elements of Mendeleev periodic table. The state diagrams of ytterbium with magnesium, calcium, strontium, and barium are constructed. The state diagrams of ytterbium with Cu, Ag, Au, Zn, Cd, Hg, B,Al, Ga, In, Tl are considered.

  13. Uptake of Hg2+ by picocyanobacteria in natural water from four Andean lakes

    Directory of Open Access Journals (Sweden)

    Diéguez M.C.

    2014-07-01

    Full Text Available In lake food webs, planktonic bacteria and algae represent the greatest bioconcentration step for Hg2+ and monomethyl-Hg (MeHg. As they are the most abundant organisms in planktonic trophic webs and also the main food resource for herbivorous plankton, they can mobilize large amounts of Hg to higher trophic levels. In Andean Patagonian lakes (Argentina, dissolved organic matter (DOM concentration and character, coupled with photo-reactions, play a central role in the complexation of Hg2+ in the water column and can even regulate the uptake of Hg2+ by planktonic algae. In this investigation we evaluated the DOM character of natural waters (NW from four Andean lakes and studied its influence on the uptake of 197Hg2+ in a strain of the picocyanobacteria Synechococcus by using Hg2+ labeled with 197Hg2+. The uptake of radiolabeled Hg2+ by Synechococcus showed different magnitude in NW of lakes Moreno, El Trébol, Morenito and Escondido. Increasing lake DOM concentration reduced the bioavailability of Hg2+ as indicated by the lower uptakes rates found in NW with higher complexity and concentration of the DOM pool. Uptakes of Hg2+ by this picocyanobacteria contrasted among NW from pelagic (surface and bottom and littoral compartments of Lake Escondido which suggest that the entry of this metal may be highly variable even in the same environment. The study of the uptake of radiolabeled Hg2+ in a set of dilutions of NW from Lake Escondido demonstrated that the bioavailability of Hg2+ decrease with increasing DOM concentration.

  14. Development of pre-concentration procedure for the determination of Hg isotope ratios in seawater samples

    International Nuclear Information System (INIS)

    Highlights: • The method for the quantitative pre-concentration of Hg from seawater was developed. • First report of Hg isotope ratios in seawater is presented. • A unique mass independent 200Hg isotope fractionation was observed. • This fractionation has unique potential to distinguish anthropogenic and natural Hg. - Abstract: Hg concentrations in seawater are usually too low to allow direct (without pre-concentration and removal of salt matrix) measurement of its isotope ratios with multicollector-inductively coupled plasma mass spectrometry (MC-ICP-MS). Therefore, a new method for the pre-concentration of Hg from large volumes of seawater was developed. The final method allows for relatively fast (about 2.5 L h−1) and quantitative pre-concentration of Hg from seawater samples with an average Hg recovery of 98 ± 6%. Using this newly developed method we determined Hg isotope ratios in seawater. Reference seawater samples were compared to samples potentially impacted by anthropogenic activity. The results show negative mass dependent fractionation relative to the NIST 3133 Hg standard with δ202Hg values in the range from −0.50‰ to −1.50‰. In addition, positive mass independent fractionation of 200Hg was observed for samples from reference sites, while impacted sites did not show significant Δ200Hg values. Although the influence of the impacted sediments is limited to the seawater and particulate matter in very close proximity to the sediment, this observation may raise the possibility of using Δ200Hg to distinguish between samples from impacted and reference sites

  15. Magnetically tunable laser emission from Hg,CdTe

    International Nuclear Information System (INIS)

    Tunable spin-flip Raman and recombination laser emission from (Hg,Cd)Te have been observed using a chopped-cw CO2 laser as the pump. Peak powers of over 1 mW and average powers of over 100 μW have been obtained for both the spin-flip Raman and recombination emissions with conversion efficiencies of over 0.3%. A zero-field g factor of vertical-bar82vertical-barplus-or-minus3 has been measured, corresponding to a conduction band-edge effective-mass ratio of 0.0098plus-or-minus0.0004

  16. A vareity of Hg capture solutions are available

    Energy Technology Data Exchange (ETDEWEB)

    Blankinship, S.

    2009-06-15

    While vacating the Clean Air Mercury Rule (CAMR) has postponed implementation of capturing mercury emitted by coal-fired power plants improvements in ways to capture and monitor mercury have continued. One method of enhancing Hg capture from FGD and SCR is to treat the coal by adding a halogen, such as calcium bromide in Alstom's KNX process prior to combustion. Power plants without FGD usually use sorbent injection, mostly an activated carbon, upstream of a particulate control device. 1 fig.

  17. HgCdTe/CdTe multiple quantum wells

    International Nuclear Information System (INIS)

    This paper reports on HgCdTe/CdTe multiple quantum wells by molecular beam epitaxy which show room temperature photoluminescence and sharp absorption steps at mid-infrared wavelengths. Quantitative chemical mapping, performed by transmission electron microscopy, indicates minimal interdiffusion during growth. Annealing experiments performed at higher temperatures show that the interdiffusion coefficient is a strong function of the depth of the interface below the surface. Absorption spectra have been accurately modeled with a square well/envelope function approach. The films have been used to passively mode lock color center lasers and produce pulses as short as 120 fsec near 2.7 μm

  18. New results on the superdeformed band in 192Hg

    International Nuclear Information System (INIS)

    New results on the 192Hg superdeformed band have been obtained with EUROGAM. The experiment has been performed with the 160Gd(36S, 4n) reaction at 159 MeV. Above 800 keV the γ-ray energies differ from the previously published ones. Thus the rise of the dynamical moment of inertia F(2) above hω = 0.4 MeV is no longer observed. This is in better agreement with recent cranked Hartree-Fock-Bogoliubov calculations. (orig.)

  19. Luminescence studies of HgCdTe alloys

    OpenAIRE

    Hunter, A. T.; McGill, T. C.

    1982-01-01

    We report the observation in Hg_(1-x)Cd_(x)Te of band-to-band, band-to-acceptor, and donor-acceptor luminescence for material of x = 0.32 and 0.5, and bound exciton recombination luminescence, for material of x = 0.5. The band-to-band lineshape and variation in intensity with pump power are appropriate to an electron-hole plasma with recombination proceeding without wave vector conservation. Differences between the spectra among the four 0. 5 samples studied are attributed to variations in...

  20. Measurement of Linear Stark Interference in 199Hg

    OpenAIRE

    Loftus, T. H.; Swallows, M. D.; Griffith, W. C.; Romalis, M. V.; Heckel, B. R.; Fortson, E. N.

    2010-01-01

    We present measurements of Stark interference in the 6$^1S_0$ $\\rightarrow$ 6$^3P_1$ transition in $^{199}$Hg, a process whereby a static electric field $E$ mixes magnetic dipole and electric quadrupole couplings into an electric dipole transition, leading to $E$-linear energy shifts similar to those produced by a permanent atomic electric dipole moment (EDM). The measured interference amplitude, $a_{SI}$ = $(a_{M1} + a_{E2})$ = (5.8 $\\pm$ 1.5)$\\times 10^{-9}$ (kV/cm)$^{-1}$, agrees with rela...

  1. Injury of Hg2+ and DBS on Lemna minor%Hg2+、DBS对浮萍的伤害研究

    Institute of Scientific and Technical Information of China (English)

    马剑敏; 王琳; 杜晋立; 吴晶敏

    2001-01-01

    The injury degree of Lemna minor by the stress of Hg2+ and DBSare reported.The concentrations of chlorophyll and dissolved protein decrease with the increase of Hg2+ and DBS concentrations or as treatment time is continued,dead percentage increase with the increase of Hg2+ and DBS concentrations or as treatment time is continued.When the concentrations of HgCl2 is 6mg/L or DBS is 12mg/L,about 70% of Lemna minor can live for 10 days at least.%研究了在Hg2+、DBS胁迫下,浮萍(LemnaminorL.)植株的枯死率、叶绿素含量和可溶性蛋白质含量的变化。植株的枯死率随Hg2+、DBS浓度升高和处理时间的延长而增加;叶绿素和蛋白质含量随Hg2+和DBS浓度升高和处理时间的延长而逐渐下降。在HgCl2、DBS浓度分别为6mg/L、12mg/L时,约70%的浮萍10d内仍存活。

  2. Hg L3 XANES Study of Mercury Methylation in Shredded Eichhornia Crassipes

    International Nuclear Information System (INIS)

    Eichhornia crassipes (water hyacinth) is a non-native plant found in abundance in the Sacramento-San Joaquin River Delta (hereafter called Delta). This species has become a problem, clogging waterways and wetlands. Water hyacinth are also known to accumulate mercury. Recent attempts to curb its proliferation have included shredding with specialized boats. The purpose of this research is to better understand the ability of water hyacinth to phytoremediate mercury and to determine the effect of shredding and anoxic conditions on mercury speciation in plant tissue. In the field assessment, total mercury levels in sediment from the Dow Wetlands in the Delta were found to be 0.273 ± 0.070 ppm Hg, and levels in hyacinth roots and shoots from this site were 1.17 ± 0.08 ppm and 1.03 ± 0.52 ppm, respectively, indicating bioaccumulation of mercury. Plant samples collected at this site were also grown in nutrient solution with 1 ppm HgCl2 under (1) aerobic conditions, (2) anaerobic conditions, and (3) with shredded plant material only. The greatest accumulation was found in the roots of whole plants. Plants grown in these conditions were also analyzed at Stanford Synchrotron Radiation Laboratory using Hg L3 X-ray Absorption Near Edge Spectroscopy (XANES), a method to examine speciation that is element-specific and noninvasive. Least-squares fitting of the XANES data to methylated and inorganic mercury(II) model compounds revealed that in plants grown live and aerobically, 5 ± 3% of the mercury was in the form of methylmercury, in a form similar to methylmercury cysteine. This percentage increased to 16 ± 4% in live plants grown anaerobically and to 22 ± 6% in shredded anaerobic plants. We conclude that shredding of the hyacinth plants and, in fact, subjection of plants to anaerobic conditions (e.g., as in normal decay, or in crowded growth conditions) increases mercury methylation. Mechanical removal of the entire plant is significantly more expensive than shredding

  3. HgL(3) XANES Study of Mercury Methylation in Shredded Eichhornia Crassipes

    Energy Technology Data Exchange (ETDEWEB)

    Rajan, M.; Darrow, J.; Hua, M.; Barnett, B.; Mendoza, M.; Greenfield, B.K.; Andrews, J.C.

    2009-05-21

    Eichhornia crassipes (water hyacinth) is a non-native plant found in abundance in the Sacramento-San Joaquin River Delta (hereafter called Delta). This species has become a problem, clogging waterways and wetlands. Water hyacinth are also known to accumulate mercury. Recent attempts to curb its proliferation have included shredding with specialized boats. The purpose of this research is to better understand the ability of water hyacinth to phytoremediate mercury and to determine the effect of shredding and anoxic conditions on mercury speciation in plant tissue. In the field assessment, total mercury levels in sediment from the Dow Wetlands in the Delta were found to be 0.273 {+-} 0.070 ppm Hg, and levels in hyacinth roots and shoots from this site were 1.17 {+-} 0.08 ppm and 1.03 {+-} 0.52 ppm, respectively, indicating bioaccumulation of mercury. Plant samples collected at this site were also grown in nutrient solution with 1 ppm HgCl{sub 2} under (1) aerobic conditions, (2) anaerobic conditions, and (3) with shredded plant material only. The greatest accumulation was found in the roots of whole plants. Plants grown in these conditions were also analyzed at Stanford Synchrotron Radiation Laboratory using Hg L{sub 3} X-ray Absorption Near Edge Spectroscopy (XANES), a method to examine speciation that is element-specific and noninvasive. Least-squares fitting of the XANES data to methylated and inorganic mercury(II) model compounds revealed that in plants grown live and aerobically, 5 {+-} 3% of the mercury was in the form of methylmercury, in a form similar to methylmercury cysteine. This percentage increased to 16 {+-} 4% in live plants grown anaerobically and to 22 {+-} 6% in shredded anaerobic plants. We conclude that shredding of the hyacinth plants and, in fact, subjection of plants to anaerobic conditions (e.g., as in normal decay, or in crowded growth conditions) increases mercury methylation. Mechanical removal of the entire plant is significantly more

  4. Distributions and Determinants of Mercury Concentrations in Toenails among American Young Adults: the CARDIA Trace Element Study

    Science.gov (United States)

    Xun, Pengcheng; Liu, Kiang; Morris, J. Steve; Jordan, Joanne M.; He, Ka

    2012-01-01

    Background Since data on mercury (Hg) levels in Caucasians and African Americans (AAs) of both genders are lacking, this study aims to present toenail Hg distributions and explore the potential determinants using data from the Coronary Artery Risk Development in Young Adults Trace Element Study. Methods Data from 4344 Americans, aged 20–32 in 1987, recruited from Oakland, Chicago, Minneapolis and Birmingham were used to measure toenail Hg levels by instrumental neutron-activation method. The Hg distribution was described with selected percentiles and geometric means. Multivariable linear regression (MLR) was used to examine potential determinants of Hg levels within ethnicity-gender subgroups. Results The geometric mean of toenail Hg was 0.212 (95% CI: 0.207–0.218) μg/g. Hg levels varied geographically with Oakland the highest [0.381 (0.367–0.395) μg/g] and Minneapolis the lowest [0.140 (0.134–0.147) μg/g]. MLR analyses showed that male gender and AA ethnicity were negatively associated with toenail Hg levels; and that age, living in Oakland city, education level, alcohol consumption and total fish intake were positively associated with toenail Hg concentrations within each ethnicity-gender subgroup. Current smokers were found to have higher Hg only in AA men. Conclusions This study suggested age, gender, ethnicity, study center, alcohol, education level and fish consumption consistently predict toenail Hg levels. As fish consumption was the key determinant, avoiding certain types of fish that have relatively high Hg levels may be crucial in reducing Hg intake. PMID:22926255

  5. Human biomonitoring for Cd, Hg and Pb in blood of inhabitants of the Sacco Valley (Italy

    Directory of Open Access Journals (Sweden)

    Sonia D'Ilio

    2013-03-01

    Full Text Available INTRODUCTION. The Sacco Valley (Lazio, Italy is characterized by high density population and several industrial chemical productions that during the time had led to a substantial amount of by-products. The result was a severe environmental pollution of the area and in particular of the river Sacco. In 1991, the analysis of water and soils samples of three industrial landfills revealed the presence of organochlorine compounds and heavy metals. A research project named "Health of residents living in Sacco Valley area", coordinated by the regional Department of Epidemiology, was undertaken and financed to evaluate the state of health of the population living near those polluted areas. MATERIALS AND METHODS. Cd, Hg and Pb were quantified in 246 blood samples of potentially exposed residents of the Sacco Valley by quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS. RESULTS. Individuals who agreed to be sampled did not exhibit high levels of the elements. The distance from the river does not seem to be directly connected with the elements levels in blood. The contribution of these contaminants to the total intake due to ingestion of food was difficult to evaluate. The unclear trend of data would require a characterization of the polluted site with environmental sampling of different matrices.

  6. An elemental diffusion description for LTE plasma models

    International Nuclear Information System (INIS)

    A novel method to describe diffusive processes in plasmas in local thermodynamic equilibrium (LTE) was developed, based on the transport of elements instead of individual species. This method combines the elegance of the LTE description of a chemical composition with the flexibility of explicit transport for each element. A simple model of a metal halide lamp containing Hg dosed with NaI is used to illustrate the method

  7. Fabrication of HgI2 nuclear radiation detectors

    International Nuclear Information System (INIS)

    HgI2 nuclear radiation detectors were fabricated and their performance was tested. Crystals of a few mm squares and about one mm thickness were grown by vapor transport method using a two-temperature-region electric furnace in which commercially-available HgI2 powder of 99.2 to 99.8%. Purity was sealed in a Pylex ampoule. Detectors were fabricated using Aquadag-paint electrodes and tested using 5.5MeV alpha-particles, 59.5keV gamma-rays and LX-rays from 241Am. The best detector showed a FWHM energy resolution of 4.9keV for 59.5 keV gamma-rays while it is difficult to obtain detectors having good energy resolution. The following were confirmed; charge collection of holes was worse than that of electrons. Crystals having better transparency and better cleavability resulted in better detector performance. Dark solidified residue was found after one vapor transport of the commercially-available powder. Humiseal paint on the detector surface improved the applicable high voltage, the long-term stability and also the energy resolution. The average energy per electron-hole pair was about 4.2eV. The energy resolution improved as the temperature decreased from 500C to 00C. The performance of the detectors made of solvent-evaporation method was worse than that made of vacuum transport method. (author)

  8. Study of Bioaccumulation Hg by Oreochromis mossambicus Using Radiotracer Techniques

    International Nuclear Information System (INIS)

    Industrial wastes are considered critical factors for disturbing the natural environment. Composite effluents tainted with different heavy metals are major environmental pollutants of varied wetland ecosystems. Coastal and estuarine areas seem to play a minor role in the global cycle of mercury. However, these areas can exhibit locally high levels of mercury directly resulting from human pollution. To reveal the presence of pollutants over time and to measure their toxic effect, the use of bio-monitors or bio-indicators can play a prominent role in the monitoring of aquatic ecosystems. Oreochromis mossambicus concentrate heavy metals in their tissues as a result of their capabilities to remove dissolved metals from the water column and can be candidate as bio-indicator. Uptake and loss kinetics of gamma-emitting radiotracers of 203Hg were determined following exposures to a one order of magnitude-range of environmentally realistic concentrations of Hg, using highly sensitive nuclear detection techniques. Using the simplest model of accumulation and loss, some of these various factors can be demonstrated, e.g., the effect of respiration rate on the uptake process. In this study, we quantified the various physiological parameters characterizing the metal bioaccumulation from dissolved uptake by Oreochromis mossambicus. (authors)

  9. MBE (Molecular Beam Epitaxial) growth characterization and electronic device processing of HgCdTe, HgZnTe related heterojunctions and HgCdTe-CdTe superlattices

    Science.gov (United States)

    Faurie, Jean-Pierre

    1987-06-01

    As the MBE growth technique has continued to improve for Hg(1-x)Cd(x)Te films, the prospects for films of larger area have begun to be explored. These larger area films are important for imaging arrays and will be especially vital in the future for the efficient production of Hg(1-x)Cd(x)Te material. The growth of MBE of uniform Hg(1-x)Cd(x)Te epilayer on a large substrate is very difficult to achieve because of the non-uniform distribution of the fluxes and on the non-uniform temperature of the substrate.

  10. Study on the application of cold vapor atomic absorption spectrometry and hydride generation atomic absorption spectrometry for the determination of Hg and As traces in sea water samples

    International Nuclear Information System (INIS)

    The trace amount of total mercury (Hg) and arsenic (As) in sea water samples were quantitatively determined by using the Atomic Absorption Spectrometry connected with the hydride generation technique (HG-AAS) for As, and with the cold vapour technique (CV-AAS) for Hg. The experiments were carried out at room temperature on a Hydride System Module (HS55) combined with an Atomic Absorption Spectrometer (VARIO 6, Analytik Jena AG). The effect of reductants concentration, and that of matrix on the absorption intensity of each analyzed element was studied in details. The sea water sample after fitrating through a membrane with 0.45(μm-hole size was pre-treated with an oxidant or an reductant to obtain the identical medium. The absorption intensity of each element was then measured on the VARIO-6 under the optimum parameters for spectrometer such as: maximum wavelength, current of hollow cathode lamp, and that for hydride system such as cell temperature, speed of peristaltic pump, pump time, reaction time and rewash time, ect. The analytical procedures were set-up and applied for the determination of these above mentioned elements in the synthesized sea water sample and in the real sea water samples with high precision and accuracy. (author)

  11. Feasibility study on the use of soil washing to remediate the As-Hg contamination at an ancient mining and metallurgy area.

    Science.gov (United States)

    Sierra, C; Menéndez-Aguado, J M; Afif, E; Carrero, M; Gallego, J R

    2011-11-30

    Soils in abandoned mining sites generally present high concentrations of trace elements, such as As and Hg. Here we assessed the feasibility of washing procedures to physically separate these toxic elements from soils affected by a considerable amount of mining and metallurgical waste ("La Soterraña", Asturias, NW Spain). After exhaustive soil sampling and subsequent particle-size separation via wet sieving, chemical and mineralogical analysis revealed that the finer fractions held very high concentrations of As (up to 32,500 ppm) and Hg (up to 1600 ppm). These elements were both associated mainly with Fe/Mn oxides and hydroxides. Textural and geochemical data were correlated with the geological substrate by means of a multivariate statistical analysis. In addition, the Hg liberation size (below 200 μm) was determined to be main factor conditioning the selection of suitable soil washing strategies. These studies were finally complemented with a specific-gravity study performed with a C800 Mozley separator together with a grindability test, both novel approaches in soil washing feasibility studies. The results highlighted the difficulties in treating "La Soterraña" soils. These difficulties are attributed to the presence of contaminants embedded in the soil and spoil heap aggregates, caused by the meteorization of gangue and ore minerals. As a result of these two characteristics, high concentrations of the contaminants accumulate in all grain-size fractions. Therefore, the soil washing approach proposed here includes the grinding of particles above 125 μm. PMID:21943924

  12. Oxidation of elemental mercury in the atmosphere; Constraints imposed by global scale modelling

    Energy Technology Data Exchange (ETDEWEB)

    Bergan, Torbjoern; Rodhe, Henning [Stockholm Univ. (Sweden). Dept. of Meteorology

    2000-05-01

    Based on the global mercury model published by Bergan et al. (1999), we present here further results from simulations where the central theme has been to evaluate the role of ozone and the hydroxyl radical as possible gas phase oxidants for the oxidation of elemental mercury in the atmosphere. The magnitude of natural and man-made mercury emissions are taken from recent literature estimates and the flux from land areas is assumed to vary by season. We consider only two mercury reservoirs, elemental mercury, Hg{sup 0}, and the more soluble divalent form, Hgll. Wet and dry deposition of Hgll is explicitly treated. Applying monthly mean fields of ozone for the oxidation of gas phase Hg{sup 0} and using the reaction rate by Hall (1995) yields a global transformation of Hg{sup 0} to Hgll which is too slow to keep the simulated concentration of Hg{sup 0} near observed values. This shows that there are additional important removal processes for Hg{sup 0} or that the reaction rate proposed by Hall (1995) is too slow. A simulation in which the oxidation rate was artificially increased, so that the global turn-over time of Hg{sup 0} was one year and the simulated average concentration of Hg{sup 0} was realistic, produced latitudinal and seasonal variations in Hg{sup 0} that did not support the hypothesis that gas phase reaction with O{sub 3} is the major oxidation process for Hg{sup 0}. Recent studies indicate that OH may be an important gas phase oxidant for Hg{sup 0}. Using OH as the oxidant and applying the preliminary oxidation rate by Sommar et al. (1999) gave an unrealistically large removal of Hg{sup 0} from the atmosphere. From calculations using a slower reaction rate, corresponding to a turn-over time of Hg{sup 0} of one year, we calculated concentrations of both Hg{sup 0} in surface air and Hgll in precipitation which correspond, both in magnitude and temporal variation, to seasonal observations in Europe and North America. This result supports the suggestion that

  13. Body burden of Hg in different bio-samples of mothers in Shenyang city, China.

    Directory of Open Access Journals (Sweden)

    Min-Ming Li

    Full Text Available Hg is an accumulative and neuro-toxic heavy metal which has a wide range of adverse effects in human health. However, few studies are available on body burden of Hg level in different bio-samples of pregnant women in Chinese population. Therefore, this study evaluated Hg levels in different maternal bio-samples in Shenyang city, China and investigated the correlation of Hg levels in different bio-samples. From October to December 2008, 200 pregnant women about to deliver their babies at ShengJing Hospital (Shenyang city, northeast of China participated in this study. The geometric mean (GM of Hg levels in cord blood, maternal venous blood, breast milk, and maternal urine were 2.18 µg/L, 1.17 µg/L, 1.14 µg/L, and 0.73 µg/L, respectively, and the GM of maternal hair Hg level was 404.45 µg/kg. There was a strong correlation between cord blood and maternal blood total Hg level (r = 0.713, P<0.001. Frequency of fish consumption more than or equal to 3 times per week during pregnancy was suggested as a significant risk factor of prenatal Hg exposure (unadjusted OR 3.5, adjusted OR 2.94, P<0.05. This study provides evidence about Hg burden of mothers and the risk factors of prenatal Hg exposure in Shenyang city, China.

  14. A preliminary study of the Hg flux from selected Ohio watersheds to Lake Erie

    International Nuclear Information System (INIS)

    New measurements of riverine dissolved and particulate Hg fluxes into Lake Erie from 12 northern Ohio watersheds have been determined from samples collected in April 2002 and analyzed using ultra-clean techniques with cold-vapor atomic fluorescence spectrometry. Total Hg concentrations ranged through 2.5-18.5 ng L-1, with a mean of 10.4 ng L-1 with most Hg in particulate form. Dissolved Hg concentrations ranged through 0.8-4.3 ng L-1, with a mean of 2.5 ng L-1. Highest total Hg concentrations were observed in western rivers with primarily agricultural land use and eastern rivers with mixed land use in their watersheds. Total suspended solid concentrations ranged through 10-180 mg L-1 with particulate Hg concentrations ranging through 47-170 ng g-1, with a mean of 99 ng g-1. Particulate Hg was similar to published data for central Lake Erie bottom sediments but much lower than for bottom sediments in western Lake Erie. Total Hg concentrations were positively correlated with suspended sediment concentrations and negatively with dissolved NO3- concentrations. The total estimated annual Hg fluxes from these rivers into Lake Erie is estimated to be 85 kg, but because only one event was sampled during high flow conditions, this may be an overestimate. This is much lower than previous published estimates of riverine Hg input into Lake Erie

  15. Wading bird guano contributes to Hg accumulation in tree island soils in the Florida Everglades

    International Nuclear Information System (INIS)

    Tree islands are habitat for wading birds and a characteristic landscape feature in the Everglades. A total of 93 surface soil and 3 soil core samples were collected from 7 degraded/ghost and 34 live tree islands. The mean Hg concentration in surface soils of ghost tree islands was low and similar to marsh soil. For live tree islands, Hg concentrations in the surface head region were considerably greater than those in mid and tail region, and marsh soils. Hg concentrations in bird guano (286 μg kg−1) were significantly higher than those in mammal droppings (105 μg kg−1) and plant leaves (53 μg kg−1). In addition, Hg concentrations and δ15N values displayed positive correlation in soils influenced by guano. During 1998–2010, estimated annual Hg deposition by guano was 148 μg m−2 yr−1 and ∼8 times the atmospheric deposition. Highlights: • Hg concentrations in the head region of tree islands were the highest. • Hg concentrations in bird guano (286 μg kg−1) were significantly higher than those in mammal droppings and plant leaves. • Hg concentrations and δ15N values showed positive correlation in soils influenced by guano. • Estimated annual Hg deposition by guano was 148 μg m−2 yr−1, ∼8 times the atmospheric deposition. -- The annual Hg deposition by bird guano to tree island soils in the Everglades was ∼8 times the atmospheric deposition

  16. Trace and toxic elements in foodstuffs in Japan

    International Nuclear Information System (INIS)

    Concentrations of trace elements in several foodstuffs collected in Japan were analyzed by neutron activation analysis (NAA), inductively-coupled plasma atomic emission spectrometry (ICP-AES) and anodic striping voltametry (ASV). The elements analyzed were as follows: Zn, Se, As, Hg, Cs, Cr, Co, Fe, Rb, Br and K by NAA; Mn, Ba, Sr, Mg, Ca, P, K, Zn, Cu and Fe by ICP-AES; and Pb, Cd, Cu and Zn by ASV. Because of the high consumption of rice in Japan, the focus of analysis was on this foodstuff. Concentrations of K, Mg, Mn, P and Zn in different polished rice samples were similar, whereas those of Br, Co, Cs, Rb and Se varied. Levels of toxic elements in polished rice were generally lower than those in other foodstuffs. The highest concentrations of As, Hg, Se and Zn were found in marine products, i.e.. Hijiki-algae (As: 59 mg/kg, dry), tuna (Hg: 1.1 mg/kg, dry), bonito (Se: 4.5 mg/kg, dry) and oysters (Zn: 350 mg/kg, dry). Dietary intakes of As, Ca, Cd, Cu, Fe, Hg, K, Mg, Mn, P, Pb, Se and Zn by Japanese were estimated by using these analytical results and published food consumption data in Japan. We have also identified the major sources of the elements in dietary intakes as follows: (a) about 90% of the As was derived from marine products (fish and seaweed); (b) about 70% of the Hg was derived from fish; (c) about 40-60% of the Cd and the Mn and 20-40% of the Zn, Cu and Mg was derived from rice; (d) selenium was mostly derived from fish, meat and eggs; (e) more than 20% of the Ca was derived from milk and milk products; (f) elements such as Fe, K, P and Pb was derived from different sorts of foodstuffs. (author). 7 refs, 1 fig., 7 tabs

  17. Application of residual sludge: effects on soil nitrogen and retention of Cd, Cr, Hg and Zn by ray grass

    International Nuclear Information System (INIS)

    In pot studies on the application of urban sewage rich in organic matter as fertilizer (residual sludges from sewage purification stations), an investigation was made of the yield in dry matter and retention of Zn, Cd, Cr and Hg by ray grass, followed by an examination of the mineralization and organization of soil nitrogen or added nitrogen fertilizers. All the experiments described were conducted with tracers - radioactive in the case of Hg, Cd, Cr and Zn, and stable in the case of nitrogen. The main results obtained after six months' cultivation can be summarized as follows: (1) the suppressing effect produced immediately after application of a lime-treated sludge falls off rapidly (2-3 months), whereas the effect produced by straw persists even after six months. The sludges subsequently exert a positive effect on the yield of dry matter; (2) in the plant the transfer of the trace elements studied is not altered by adding residual sludges whereas the addition of 30 ppm of these elements to the soil in ionic form increases the plant content; (3) although the incorporation of straw into the soil considerably increases the organization of the nitrogen in the fertilizer applied, the changes are limited in the case of other forms of treatment. (author)

  18. Analysis of toxic trace elements in sea food samples by neutron activation

    International Nuclear Information System (INIS)

    The contents of toxic and essential trace element were analysed such as As, Hg, Se and Zn by neutron activation analysis in coastal fishes consumed by the general population of Malaysia. The mean values of the elements analysed expressed in mg/kg fresh weight ranged 1.42-5.61, 0.06-0.42, 4.2-20.6, 0.41-1.28 for As, Hg, Zn and Se, respectively. The maximum permissible limit for As in food was set at 1.0 mg/kg under the Malaysian Food Regulations. The results showed that consumption of coastal fishes is not permitted under the regulations, while the levels of Hg, Se and Zn were within the permissible limits. The daily dietary intake of As and Hg at 400 μg and 30 μg respectively are still within the tolerance levels. (author) 9 refs.; 2 tabs

  19. Dynamic recycling of gaseous elemental mercury in the boundary layer of the Antarctic Plateau

    Directory of Open Access Journals (Sweden)

    A. Dommergue

    2012-11-01

    Full Text Available Gaseous elemental mercury (Hg0 was investigated in the troposphere and in the interstitial air extracted from the snow at Dome Concordia station (alt. 3320 m on the Antarctic Plateau during January 2009. Measurements and modeling studies showed evidence of a very dynamic and daily cycling of Hg0 inside the mixing layer with a range of values from 0.2 ng m−3 up to 2.3 ng m−3. During low solar irradiation periods, fast Hg0 oxidation processes in a confined layer were suspected. Unexpectedly high Hg0 concentrations for such a remote place were measured under higher solar irradiation due to snow photochemistry. We suggest that a daily cycling of reemission/oxidation occurs during summer within the mixing layer at Dome Concordia. Hg0 concentrations showed a negative correlation with ozone mixing ratios, which contrasts with atmospheric mercury depletion events observed during the Arctic spring. Unlike previous Antarctic studies, we think that atmospheric Hg0 removal may not be the result of advection processes. The daily and dramatic Hg0 losses could be a consequence of surface or snow induced oxidation pathways. It remains however unclear whether halogens are involved. The cycling of other oxidants should be investigated together with Hg species in order to clarify the complex reactivity on the Antarctic plateau.

  20. Immobilization of aqueous Hg(II) by mackinawite (FeS)

    International Nuclear Information System (INIS)

    As one of the major constituents of acid volatile sulfide (AVS) in anoxic sediments, mackinawite (FeS) is known for its ability to scavenge trace metals. The interaction between aqueous Hg(II) (added as HgCl2) and synthetic FeS was studied via batch sorption experiments conducted under anaerobic conditions. Due to the release of H+ during formation of hydrolyzed Hg(II) species which is more reactive than Hg2+ in surface adsorption, the equilibrium pH decreased with the increase in Hg(II)/FeS molar ratio. Counteracting the loss of FeS solids at lower pH, the maximum capacity for FeS to remove aqueous Hg(II) was approximately 0.75 mol Hg(II) (mol FeS)-1. The comparison of X-ray power diffraction (XRPD) patterns of synthetic FeS sorbent before and after sorption showed that the major products formed from the interaction between FeS and the aqueous Hg(II) were metacinnabar, cinnabar, and mercury iron sulfides. With the addition of FeS at 0.4 g L-1 to a 1 mM Hg(II) solution with an initial pH of 5.6, Fe2+ release was approximately 0.77 mol Fe2+ per mol Hg(II) removed, suggesting that 77% of Hg(II) was removed via precipitation reaction under these conditions, with 23% of Hg(II) removed by adsorption. Aeration does not cause significant release of Hg(II) into the water phase

  1. Barium triel mercuride BaMxHg4-x and Ba3MxHg11-x (M = Ga, In, Cd)

    International Nuclear Information System (INIS)

    The systematic experimental and bond-theoretical study of the phase width of the BaAl4 structure type in the ternary system BaIn4-BaHg4 shows that this structure type is stable up to BaIn1.7Hg2.3 (tetragonal, tI10, space group I4/mmm, a = 474.2(3), c = 1228.7(9) pm, R1 = 0.0529). The planar 44 layers (M(2) site) are preferentially formed by In, whereas Hg occupies the tips (M(1) site) of the [M(1)M(2)4] square pyramids. The layers of the pyramids are connected via short M(1)-M(1) dumbbells (bonds a). The analysis of the calculated band structures of BaIn2Hg2 in comparison to BaIn4 and RbIn4 shows that contributions of Ba-d states (which are missing for RbIn4) and Hg-d states (which are missing in the pure indides) are significant. The respective compound with the smaller triel gallium (Hg-richest phase: BaGa1.9Hg2.1, tetragonal, oI40, space group I41/amd, a = 671.3(2), c = 2220.4(8) pm, Z = 8, R1 = 0.0641) forms a new superstructure of the BaAl4 structure with a partial ordering of three statistically occupied mixed Ga/Hg positions. The 44 nets are formed by an intermediate proportion of Ga/Hg. The tips of the pyramids are alternately formed by a Ga- and an Hg-rich position leading to smaller and larger bond lengths a' and a'', respectively, between the tip atoms and, consequently, a puckering of the 44 net. The two Hg-rich 3:11 compounds Ba3InHg10 and Ba3CdHg10 (orthorhombic, oI28, space group Immm, a = 513.96(8)/511.50(2), b = 993.8(2)/991.54(3), c = 1500.7(3)/1499.26(5) pm, Z = 2, R1 = 0.0619/0.0482) crystallize in the La3Al11 structure type, which is also observed for K3Hg11 and is closely related to the BaAl4 type: The square pyramidal nets are corrugated leading to a triplication of the BaAl4 unit cell along one of the tetragonal axes. In each third subcell the tips of adjacent pyramids are directly fused, this position being occupied exclusively by In and Cd. With the smaller triel gallium, the 3:11 compound Ba3Ga0.2Hg10.8 crystallizes in the Ba3ZnHg10

  2. Concentration and distribution of toxic elements in rice and husk

    International Nuclear Information System (INIS)

    Five varieties of rice were analyzed to study the prevailing concentration and distribution of 10 trace elements in rice and rice husk. NAA in combination with AAS was utilized for the determination of Hg, Pb, Cd, As, Br, Sb, Se, Ni, Al and Cs. The elemental ratios of rice to husk and within rice was calculated to get information on their uptake channels. The daily supply of the elements to the human body was estimated and from these the safety of the diet was assessed by comparing with the suggested tolerance levels. A global distribution pattern of some of these elements in rice was also evaluated. (author) 30 refs.; 3 figs.; 6 tabs

  3. PELTIER ELEMENTS

    CERN Document Server

    Tani, Laurits

    2015-01-01

    To control Peltier elements, temperature controller was used. I used TEC-1091 that was manufactured my Meerstetter Engineering. To gain control with the temperature controller, software had to be intalled on a controlling PC. There were different modes to control the Peltier: Tempererature controller to control temperature, Static current/voltage to control voltage and current and LIVE ON/OFF to auto-tune the controller respectively to the system. Also, since near the collision pipe there is much radiation, radiation-proof Peltier elements have to be used. To gain the best results, I had to find the most efficient Peltier elements and try to get their cold side to -40 degrees Celsius.

  4. HG/LT-GC/ICP-MS coupling for identification of metal(loid) species in human urine after fish consumption

    Energy Technology Data Exchange (ETDEWEB)

    Kresimon, J.; Grueter, U.M.; Hirner, A.V. [Inst. of Environmental Analytical Chemistry, University of Essen (Germany)

    2001-11-01

    Human urine samples after fish consumption have been investigated by low-temperature gas chromatography with inductively coupled plasma mass spectrometric detection after sample derivatization by hydride generation (HG/LT-GC/ICP-MS). This analytical technique enabled the identification of organometal(loid) compounds in human urine; species of the six elements germanium, arsenic, selenium, tin, antimony, and mercury were determined.Three different organic selenium species, two germanium species, seven arsenic species, four tin species, five antimony species, and one species of mercury were found; 18 of the 22 species detected could be identified. The relative detection limits ranged between 2 and 12 pg x L{sup -1} (x=element). These organometal(loid) compounds probably build up in the human body under the influence of micro-organisms, in the presence of hydrogen sulfide and methane, in the human intestine. (orig.)

  5. A Novel Sample Introduction Technique for the Simultaneous Determination of As, Se, Ge and Hg in Chinese Medicinal Material

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A novel technique of Moveable Reduction Bed Hydride Generator(MRBHG) was applied to the hydride generation or cold vapor generation of As, Se, Ge, and Hg existing in Traditional Chinese Medicinal Material(TCM). The simultaneous determination of the multi-elements was performed with ICP-MS. A solid reduction system involving the use of potassium tetraborohydride and tartaric acid was applied to generating metal hydride or cold vapor efficiently. The factors affecting the metal cold vapor generation were studied. The main advantage of the technique is that only a 4 μL volume of sample was required for the cold vapor generation. The absolute detection limits of all the elements studied are in 10-12 g level.

  6. Multiconfiguration Dirac-Hartree-Fock calculations of atomic electric dipole moments of 225^Ra, 199^Hg, and 171^Yb

    CERN Document Server

    Radziute, Laima; Jonsson, Per; Biero, Jacek

    2013-01-01

    The multiconfiguration Dirac-Hartree-Fock (MCDHF) method has been employed to calculate atomic electric dipole moments (EDM) of 225^Ra, 199^Hg, and 171^Yb. For the calculations of the matrix elements we extended the relativistic atomic structure package GRASP2K. The extension includes programs to evaluate matrix elements of (P, T)-odd e-N tensor-pseudotensor and pseudoscalar-scalar interactions, the atomic electric dipole interaction, the nuclear Schiff moment, and the interaction of the electron electric dipole moment with nuclear magnetic moments. The interelectronic interactions were accounted for through valence and core-valence electron correlation effects. The electron shell relaxation was included with separately optimised wave functions of opposite parities.

  7. Radionuclides for investigating the accumulation of toxic elements in algae and fish

    International Nuclear Information System (INIS)

    Radionuclides are very suitable for investigating the accumulation of toxic elements in algae and fish. The most important results obtained from using 51Cr(III) (VI), 65Zn, 74As(III) (V), CH374AsO(OH)2, (CH3)274AsO(OH), (CH3)374As, 85Sr, 86Rb, /sup 115m/Cd, 133Ba, 137Cs, 203Hg(II), CH3203HgCl and C6H5203HgCl for the study of the accumulation, release and chemical transformation of the above species in algae and fish are summarized. (author)

  8. Radiographic element

    International Nuclear Information System (INIS)

    Radiographic elements are disclosed having first and second silver halide emulsion layers comprised of a dispersing medium and radiation-sensitive silver halide grains, and a support interposed between said silver halide emulsion layers capable of transmitting radiation to which said second silver halide emulsion layer is responsive. These elements are characterized in that at least said first silver halide emulsion layer contains tabular silver halide grains and spectral sensitizing dye adsorbed to the surface of the grains. Crossover can be improved in relation to the imaging characteristics. (author)

  9. A review of trace element emissions from the combustion of refuse-derived fuel with coal

    International Nuclear Information System (INIS)

    The effects of cocombusting refuse-derived fuel (RDF) with coal on stack emissions of trace elements in the ash stream were reviewed. The large number of variables and uncertainties involved precluded drawing definitive conclusions regarding many of the trace elements. However, it is evident that cocombustion resulted in increased emissions of Cd, Cu, Hg, Pb, and Zn. Emissions of As and Ni tended to decrease when RDF was fired with coal. Modeling studies indicated that ambient levels of trace elements during cocombustion should be within acceptable limits. However, periodic monitoring of Cd, Hg, and Pb may be warranted in some instances

  10. Excitation of Rydberg states of HgCl2 and HgBr2 by electron impact

    International Nuclear Information System (INIS)

    We have examined the electronic structure of HgCl2 and HgBr2 from 5 eV to 14 eV by high-resolution electron energy-loss spectroscopy. Our measurements include the near-UV region, which has not been examined by any previous technique and which is found to be rich in Rydbery states. In particular, in each molecule we identify members of two optically allowed Rydberg series and one forbidden series with electronic structures sigma/sub g/2 sigma/sub u/2 π/sub u/4 π/sub g/3 [npπ/sub u/, npsigma/sub u/ and ndπ/sub g/, or (n+1)ssigma/sub g/] that converge to the 2PI/sub g/ ground ionic state. In addition, other structures that form the dominant energy-loss mechanisms in our spectra are identified as arising from optically allowed Rydberg states associated with the excited ionic states 2PI/sub u/, 2Σ/sub u/, and 2Σ/sub g/. Measurements at energy losses below 9 eV confirm previous valence states observed in photoabsorption and suggest the existence of two new valence states in each molecule. Angular measurements facilitate identification of many of the newly observed structures in our electron energy-loss spectra

  11. Sensitivity analysis of an updated bidirectional air–surface exchange model for elemental mercury vapor

    OpenAIRE

    Wang, X.; Lin, C.-J.; Feng, X.

    2014-01-01

    A box model for estimating bidirectional air–surface exchange of gaseous elemental mercury (Hg0) has been updated based on the latest understanding of the resistance scheme of atmosphere–biosphere interface transfer. Simulations were performed for two seasonal months to evaluate diurnal and seasonal variation. The base-case results show that water and soil surfaces are net sources, while vegetation is a net sink of Hg0. The estimated net exchange in a domain covering the con...

  12. Modification and characterization of PET fibers for fast removal of Hg(II), Cu(II) and Co(II) metal ions from aqueous solutions.

    Science.gov (United States)

    Monier, M; Abdel-Latif, D A

    2013-04-15

    A new chelating fiber (PET-TSC) was prepared with PET for fast removal of Hg(2+), Cu(2+) and Co(2+) from water. Elemental analysis, SEM, BET surface area, (13)C NMR, FTIR and X-ray diffraction spectra were used to characterize PET-TSC. The higher uptake capacity of the studied metal ions was observed at higher pH values. Kinetic study indicated that the adsorption of Hg(2+), Cu(2+) and Co(2+) followed the pseudo-second-order equation, suggesting chemical sorption as the rate-limiting step of the adsorption process. The best interpretation for the equilibrium data was given by Langmuir isotherm, and the maximum adsorption capacities were 120.02, 96.81 and 78.08 mg/g for Hg(2+), Cu(2+) and Co(2+) ions, respectively. 1M HCl or 0.1M EDTA could be used as effective eluant to desorb the Hg(2+), Cu(2+) and Co(2+) adsorbed by PET-TSC, and the adsorption capacity of PET-TSC for the three heavy metal ions could still be maintained at about 90% level at the 5th cycle. Accordingly, it is expected that PET-TSC could be used as a promising adsorbent for fast removal of heavy metal ions from water, and the present work also might provide a simple and effective method to reuse the waste PET fibers. PMID:23435202

  13. Sediment accumulation and mercury (Hg) flux in Avicennia marina forest of Deep Bay, China

    Science.gov (United States)

    Li, Ruili; Chai, Minwei; Guo, Meixian; Qiu, Guo Yu

    2016-08-01

    To investigate the rate of sediment accumulation and mercury (Hg) flux in Avicennia marina forest of Deep Bay, China, sediment cores were analyzed. The results showed that Hg concentrations were much higher at all depths compared to the background level. A high correlation between Hg and total organic carbon (TOC) indicated their similar anthropogenic origin. Sedimentation rate was estimated to be 1.38 cm a-1 by 210Pb geochronology. The increase in the mass sediment accumulation rates was rapid (range: 0.5-0.94 g cm-2 a-1), and the Hg fluxes ranged between 76 and 116 ng cm-2 a-1 during the last three decades. The reduction in both Hg concentrations and flux during the last decade may be due to the adoption of contamination control policies. Our results support the notion that the Hg fluxes determined from the sediment cores reveal the effects of anthropogenic influences from the areas around Deep Bay.

  14. Admittance Investigation of MIS Structures with HgTe-Based Single Quantum Wells.

    Science.gov (United States)

    Izhnin, Ihor I; Nesmelov, Sergey N; Dzyadukh, Stanislav M; Voitsekhovskii, Alexander V; Gorn, Dmitry I; Dvoretsky, Sergey A; Mikhailov, Nikolaj N

    2016-12-01

    This work presents results of the investigation of admittance of metal-insulator-semiconductor structure based on Hg1 - x Cd x Te grown by molecular beam epitaxy. The structure contains a single quantum well Hg0.35Cd0.65Te/HgTe/Hg0.35Cd0.65Te with thickness of 5.6 nm in the sub-surface layer of the semiconductor. Both the conductance-voltage and capacitance-voltage characteristics show strong oscillations when the metal-insulator-semiconductor (MIS) structure with a single quantum well based on HgTe is biased into the strong inversion mode. Also, oscillations on the voltage dependencies of differential resistance of the space charge region were observed. These oscillations were related to the recharging of quantum levels in HgTe. PMID:26831691

  15. Electro-physical characteristics of MIS structures with HgTe- based single quantum wells

    Science.gov (United States)

    Dzyadukh, S.; Nesmelov, S.; Voitsekhovskii, A.; Gorn, D.

    2015-12-01

    The paper presents brief research results of the admittance of metal-insulator- semiconductor (MIS) structures based on Hg1-xCdxTe grown by molecular-beam epitaxy (MBE) method including single HgCdTe/HgTe/HgCdTe quantum wells (QW) in the surface layer. The thickness of a quantum well was 5.6 nm, and the composition of barrier layers with the thickness of 35 nm was close to 0.65. Measurements were conducted in the range of temperatures from 8 to 200 K. It is shown that for structure with quantum well based on HgTe capacitance and conductance oscillations in the strong inversion are observed. Also it is assumed these oscillations are related with the recharging of quantum levels in HgTe.

  16. Admittance Investigation of MIS Structures with HgTe-Based Single Quantum Wells

    Science.gov (United States)

    Izhnin, Ihor I.; Nesmelov, Sergey N.; Dzyadukh, Stanislav M.; Voitsekhovskii, Alexander V.; Gorn, Dmitry I.; Dvoretsky, Sergey A.; Mikhailov, Nikolaj N.

    2016-02-01

    This work presents results of the investigation of admittance of metal-insulator-semiconductor structure based on Hg1 - x Cd x Te grown by molecular beam epitaxy. The structure contains a single quantum well Hg0.35Cd0.65Te/HgTe/Hg0.35Cd0.65Te with thickness of 5.6 nm in the sub-surface layer of the semiconductor. Both the conductance-voltage and capacitance-voltage characteristics show strong oscillations when the metal-insulator-semiconductor (MIS) structure with a single quantum well based on HgTe is biased into the strong inversion mode. Also, oscillations on the voltage dependencies of differential resistance of the space charge region were observed. These oscillations were related to the recharging of quantum levels in HgTe.

  17. Effects of 1-MeV proton irradiation in Hg-based cuprate thin films

    International Nuclear Information System (INIS)

    We have studied the effects of 1-Mev proton irradiation on both superconducting properties and normal state resistivity of high-quality HgBa2CaCu2O6+δ (Hg-1212) and HgBa2Ca2Cu3O8+δ (Hg-1223) thin films. At low proton doses, we observed a linear decrease of the superconducting transition temperature Tc and a linear increase of the extrapolated residual resistivity as proton dose is increased. This is consistent with observations of other high-Tc superconductors while a lower dose threshold for suppressing the superconductivity is found in Hg-1212 and Hg-1223 films. To explain the linear dose dependence of Tc, we propose a model based on the proximity effect. An enhancement of up to 90% in the critical current density at low fields has also been observed in these films at low proton fluences that do not significantly degrade Tc. copyright 1997 The American Physical Society

  18. Food preferences and Hg distribution in Chelonia mydas assessed by stable isotopes.

    Science.gov (United States)

    Bezerra, M F; Lacerda, L D; Rezende, C E; Franco, M A L; Almeida, M G; Macêdo, G R; Pires, T T; Rostán, G; Lopez, G G

    2015-11-01

    Mercury (Hg) is a highly toxic pollutant that poses in risk several marine animals, including green turtles (Chelonia mydas). Green turtles are globally endangered sea turtle species that occurs in Brazilian coastal waters as a number of life stage classes (i.e., foraging juveniles and nesting adults). We assessed total Hg concentrations and isotopic signatures ((13)C and (15)N) in muscle, kidney, liver and scute of juvenile green turtles and their food items from two foraging grounds with different urban and industrial development. We found similar food preferences in specimens from both areas but variable Hg levels in tissues reflecting the influence of local Hg backgrounds in food items. Some juvenile green turtles from the highly industrialized foraging ground presented liver Hg levels among the highest ever reported for this species. Our results suggest that juvenile foraging green turtles are exposed to Hg burdens from locally anthropogenic activities in coastal areas. PMID:26196313

  19. Characterization of the native defects in HgTe, CdTe, Hg1-x, CdxTe by positron annihilation: evidence of native vacancies

    International Nuclear Information System (INIS)

    Direct evidence of native vacancies is found in as-grown CdxHg1-xTe single crystals prepared by the travelling heating method (THM). The vacancies have characteristics depending on the annealing undergone by the crystals after their growth and on the conduction type in the crystals. In as-grown CdTe and Cd0.7Hg0.3Te (THM), native vacancies are found in n-type materials. In as-grown HgTe and Cd0.2Hg0.8Te (THM), native vacancies are found in p materials. They disappear after stoechiometric annealings in which the crystals are converted n-type. From the positron lifetime at the vacancies, 320±4 ps, one can show that the native vacancies are metallic vacancies VCd in CdTe, VHg in HgTe, VHg or/and VCd in CdxHg1-xTe alloys. The concentration of the metallic vacancies is estimated in as-grown crystals. In as-grown p-type CdTe and Cd0.7Hg0.3Te (THM), in as-grown then subsequently p-type annealed HgTe and Cd0.2Hg0.8Te (THM), vacancy type defects are also found giving rise to lifetime of about 290 ps. These defects are also found in crystals grown by Bridgman method. The nature of these defects is discussed. The In doping effects on the metallic vacancies have been studied. It is shown that In addition increases the concentration of metallic vacancies in CdTe (In) (THM). Vacancy-In complexes appear for In concentrations of the order or above 1017 cm-3. These complexes disappear after decompensating annealings and only the metallic vacancies survive. Small vacancies clusters of two or three vacancies are found after deformation at room temperature in CdTe (Mn) (THM)

  20. Study on trace elements in gangue in Huainan mining area

    Energy Technology Data Exchange (ETDEWEB)

    Cai, F.; Liu, Z.; Lin, B.; Li, W.; Lu, Z. [Anhui University of Science and Technology, Huainan (China)

    2008-08-15

    46 samples were gathered from coal seams and rocks of various lithological types. In these samples, trace elements were analyzed by inductively coupled plasma-mass spectrometry (IAP-MS)and instrumental neutron activation analysis (IAA). Hg was analyzed by cold-vapor atomic absorption spectrometry (KVASS), F by ion-selective electrode (IS) and major elements by chemical methods. Eleven trace elements (Cd, Cu, Ni, Sn, Hg, Mn, As, Cr, Pb, Zn, F) were selected for study, and five of them, Cd, Cu, Ni, Sn, Hg, were above the background soil level (B.L.) of Huainan City, China and world averages. Respectively: Cd is 40 and 7 times the B.L. of Huainan City and the world; Cu is about 2 and 1.5 times the B.L. of Huainan City and the world; Ni is 8 and 7 times the B.L. of Huainan City and the world; Sn is 3 and 2 times the B.L. of Huainan City and the world; and Hg is 3,602 and 1,381 times the B.L. of Huainan City and the world. Their hazards caused to the environment of the mining area are explored primarily. It is thought that their hazards may be cumulative. 15 refs., 1 fig., 3 tabs.

  1. Stoichiometry, thickness and crystallinity of MOCVD grown Hg1x-yCdxMnyTe determined by nuclear techniques of analysis

    International Nuclear Information System (INIS)

    The quaternary semi-conductor Hg1-x-yCdxMnyTe has been grown by Metal Organic Chemical Vapour Deposition using the Interdiffused Multi-layer Process. The layers have been analysed by Ion beam (PIXE, RBS, channeling) and related analytical techniques (EDXRF, XRD, RHEED) to obtain stoichiometric and structural information. The analysis shows that all four elements are present throughout the layer and that the elemental concentrations and thickness of the layer vary considerably over the film. Channeling, XRD and RHEED have been combined to show that the layer is polycrystalline. 14 refs., 3 figs

  2. Superheavy element flerovium (element 114) is a volatile metal.

    Science.gov (United States)

    Yakushev, Alexander; Gates, Jacklyn M; Türler, Andreas; Schädel, Matthias; Düllmann, Christoph E; Ackermann, Dieter; Andersson, Lise-Lotte; Block, Michael; Brüchle, Willy; Dvorak, Jan; Eberhardt, Klaus; Essel, Hans G; Even, Julia; Forsberg, Ulrika; Gorshkov, Alexander; Graeger, Reimar; Gregorich, Kenneth E; Hartmann, Willi; Herzberg, Rolf-Dietmar; Hessberger, Fritz P; Hild, Daniel; Hübner, Annett; Jäger, Egon; Khuyagbaatar, Jadambaa; Kindler, Birgit; Kratz, Jens V; Krier, Jörg; Kurz, Nikolaus; Lommel, Bettina; Niewisch, Lorenz J; Nitsche, Heino; Omtvedt, Jon Petter; Parr, Edward; Qin, Zhi; Rudolph, Dirk; Runke, Jörg; Schausten, Brigitta; Schimpf, Erwin; Semchenkov, Andrey; Steiner, Jutta; Thörle-Pospiech, Petra; Uusitalo, Juha; Wegrzecki, Maciej; Wiehl, Norbert

    2014-02-01

    The electron shell structure of superheavy elements, i.e., elements with atomic number Z ≥ 104, is influenced by strong relativistic effects caused by the high Z. Early atomic calculations on element 112 (copernicium, Cn) and element 114 (flerovium, Fl) having closed and quasi-closed electron shell configurations of 6d(10)7s(2) and 6d(10)7s(2)7p1/2(2), respectively, predicted them to be noble-gas-like due to very strong relativistic effects on the 7s and 7p1/2 valence orbitals. Recent fully relativistic calculations studying Cn and Fl in different environments suggest them to be less reactive compared to their lighter homologues in the groups, but still exhibiting a metallic character. Experimental gas-solid chromatography studies on Cn have, indeed, revealed a metal-metal bond formation with Au. In contrast to this, for Fl, the formation of a weak bond upon physisorption on a Au surface was inferred from first experiments. Here, we report on a gas-solid chromatography study of the adsorption of Fl on a Au surface. Fl was produced in the nuclear fusion reaction (244)Pu((48)Ca, 3-4n)(288,289)Fl and was isolated in-flight from the primary (48)Ca beam in a physical recoil separator. The adsorption behavior of Fl, its nuclear α-decay product Cn, their lighter homologues in groups 14 and 12, i.e., Pb and Hg, and the noble gas Rn were studied simultaneously by isothermal gas chromatography and thermochromatography. Two Fl atoms were detected. They adsorbed on a Au surface at room temperature in the first, isothermal part, but not as readily as Pb and Hg. The observed adsorption behavior of Fl points to a higher inertness compared to its nearest homologue in the group, Pb. However, the measured lower limit for the adsorption enthalpy of Fl on a Au surface points to the formation of a metal-metal bond of Fl with Au. Fl is the least reactive element in the group, but still a metal. PMID:24456007

  3. Excitation spectra and ground-state properties from density functional theory for the inverted band-structure systems $\\beta$-HgS, HgSe, and HgTe

    CERN Document Server

    Delin, A

    2002-01-01

    We have performed a systematic density-functional study of the mercury chalcogenide compounds $\\beta$-HgS, HgSe, and HgTe using an all-electron full-potential linear muffin-tin orbital (FP-LMTO) method. We find that, in the zinc-blende structure, both HgSe and HgTe are semimetals whereas $\\beta$-HgS has a small spin-orbit induced band gap. Our calculated relativistic photoemission and inverse photoemission spectra (PES and IPES, respectively) reproduce very well the most recently measured spectra, as do also our theoretical optical spectra. In contrast to the normal situation, we find that the local density approximation (LDA) to the density functional gives calculated equilibrium volumes in much better agreement with experiment than does the generalized gradient corrected functional (GGA). We also address the problem of treating relativistic $p$ electrons with methods based on a scalar-relativistic basis set, and show that the effect is rather small for the present systems.

  4. Anthropogenic Hg in the ocean: Trajectories of change and implications for exposure in the United States

    Science.gov (United States)

    Amos, H. M.; Corbitt, E. S.; Bullard, K. T.; Sunderland, E. M.

    2014-12-01

    Humans have been releasing mercury (Hg) to the environment for millenia through activities such as mining and fuel combustion. The result has been an enrichment of the ocean, atmosphere, and terrestrial ecosystems. Consumption of marine fish contaminated with methylmercury (MeHg) is the primary route of exposure in many populations globally. We present an updated analysis of sources of MeHg exposures in the United States that shows the majority (>70%) is from oceanic fish rather than coastal species. Using a fully coupled biogeochemical box model we also estimate Hg accumulation across major ocean basins and show anthropogenic enrichment is highest in the North Atlantic Ocean and lowest in the deep Pacific Ocean. Our results for contemporary ocean concentrations are consistent with recent data from the Pacific, Atlantic, Indian and Southern Oceans measured as part of the CLIVAR repeat hydrography program. Our estimates of natural (i.e., pre-anthropogenic) seawater Hg concentrations are lower than suggested by other studies, implying a greater anthropogenic perturbation in the ocean. Our work suggests total accumulation of anthropogenic Hg in the global oceans is greater than recently derived based on anthropogenic CO2. We compare modeled seawater concentrations since 1980 to observations over this period to evaluate evidence for changes in recent decades and then investigate potential impacts of changing global emissions. To do this, we use a range of historical and future anthropogenic Hg emission inventories. Our previous work using the box model indicates burial of Hg at ocean margins is the single largest global sink of anthropogenic Hg. We will discuss how the magnitude and permanence of this sink affects estimates of enrichment and time scales of recovery in all geochemical Hg reservoirs. Governing time scales of response in each ocean basin are diagnosed using eigenanalysis and discussed in the context of changes in human MeHg exposure resulting from

  5. ELECTRON TRANSFER IN Hg1-xCdxTe-CdTe HETEROSTRUCTURES

    OpenAIRE

    Boebinger, G.; Vieren, J.; Guldner, Y.; Voos, M.; Faurie, J.

    1987-01-01

    Far infrared magneto-absorption experiments performed at 1.6K in HgCdTe-CdTe heterojunctions show that a two-dimensional electron gas is formed in the HgCdTe layer at the HgCdTe-CdTe interface. The electron effective masses of the two populated subbands is obtained and compared to previous theoretical calculations. The electron transfer across the interface involves deep traps in the CdTe layers.

  6. Atomic mass determinations for 183W and 199Hg and the mercury problem

    International Nuclear Information System (INIS)

    Recent modifications to the 'Manitoba II' high resolution mass spectrometer are described. Mass differences among the members of the triplet 199 Hg -183W 16O- 12C 235 Cl 5 have been measured. These self-consistent mass differences give masses for 183W and 199Hg, as well as the mass difference across the W to Hg region of the mass table. These masses and the mass difference provide important constraints for the least squares atomic mass evaluation

  7. 46 CFR 53.05-3 - Materials (modifies HG-401.2).

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Materials (modifies HG-401.2). 53.05-3 Section 53.05-3... Pressure Relieving Devices (Article 4) § 53.05-3 Materials (modifies HG-401.2). Materials for valves must be in accordance with HG-401.2 of section IV of the ASME Boiler and Pressure Vessel...

  8. A simple and efficient dual optical signaling chemodosimeter for toxic Hg(II

    Directory of Open Access Journals (Sweden)

    Sabir H. Mashraqui

    2012-08-01

    Full Text Available 10-Methylthioacridone, designated as acrithion, has been employed as an easily accessible chemodosimeter for the optical targeting of toxic Hg2+ in buffered aqueous DMSO. The Hg2+-mediated desulfurization of the probe is translated into selective dual signaling of Hg2+ by means of color bleaching and fluorescence amplification while several other metal ions, including potentially competing Ag+, Cu2+ and Pb2+, afford no significant interferences even in excess concentrations.

  9. Lifetimes of an excited superdeformed band in {sup 192}Hg

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, I.; Blumenthal, D.; Carpenter, M.P. [and others

    1995-08-01

    An excited superdeformed band was identified in {sup 192}Hg and the lifetimes of its levels measured with the Doppler-shift attenuation method from data taken with the Eurogam spectrometer. The band is proposed to be based on the two-quasineutron (v[642]3/2 [512]5/2) configuration, which after a band crossing, becomes the (v[642]3/2 [752]5/2) configuration. The transition quadrupole moment Q{sub t} of the excited band is the same as that of the yrast SD band, within experimental errors. This suggests that the deformation of the SD minimum is robust with respect to quasiparticle excitation, despite the occupation of the deformation-driving v[752]5/2 level (from the j{sub 15/2} shell) after the band crossing.

  10. Mercuric iodide (HgI2) growth for nuclear detectors

    Science.gov (United States)

    Schnepple, W.

    1982-01-01

    The purpose of this investigation is to grow more-perfect mercuric iodide crystals in a low-gravity environment by taking advantage of diffusion-controlled growth conditions and by avoiding the problem of strain dislocations produced by the crystal's weight. This crystal has considerable practical importance as a sensitive gamma-ray detector and energy spectrometer that can operate at ambient temperature, as compared to presently available detectors that must be cooled to near liquid nitrogen temperatures. However, the performance of mercuric iodide crystals only rarely approaches the expected performance, presumably because some of the free electrical charges produced within the crystal are not collected at the electrodes, but instead remain trapped or immobilized at crystal defects. An efficient high atomic number semiconductor detector capable of operating at room temperature utilizing single HgI2 crystals offers a greater potential than existing detector technology.

  11. Topological Superconductivity in HgTe-based Devices

    Science.gov (United States)

    Molenkamp, Laurens

    Suitably structured HgTe has been shown to be a topological insulator in both 2- (a quantum well wider than some 6.3 nm) and 3 (an epilayer grown under tensile strain) dimensions with favorable properties for quantum transport studies, i.e. a good mobility and a complete absence of bulk carriers. In this talk I will summarize the results of our efforts (in collaboration with colleagues all over the globe) to induce superconductivity in the topological surface states of these materials. Special emphasis will be given to recent results on the ac Josephson effect. We will present data on Shapiro step behavior that is a very strong indication for the presence of a gapless Andreev mode in our Josephson junctions.

  12. Thomson scattering on high pressure Hg discharge lamps

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, X [Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB, Eindhoven (Netherlands); Vries, N de [Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB, Eindhoven (Netherlands); Kieft, E R [Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB, Eindhoven (Netherlands); Mullen, J J A M van der [Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB, Eindhoven (Netherlands); Haverlag, M [Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB, Eindhoven (Netherlands); Central Development Lighting, Philips Lighting, PO Box 80020, 5600 JM, Eindhoven (Netherlands)

    2005-06-21

    Thomson scattering (TS) experiments have been performed on high-pressure Hg discharge lamps. These lamps were filled with different amounts of Hg (15, 30, 50 and 70 mg) and were operating at different powers (150, 200 and 240 W) with a square-wave ballast. As in the previous studies (Zhu X et al 2004 J. Phys. D: Appl. Phys. 37 736-43) a triple grating spectrograph was used to suppress the false stray light and Rayleigh scattered photons. This set-up had to be modified for this special application. The collective TS spectra have been fitted using both a calibration using Raman scattering and a form fitting procedure. It was found that the electron temperature fluctuates around a certain value that seems rather constant in the central region. The value of electron temperature (T{sub e}) varies between 5500 and 7600 K in the central region (r {<=} 0.3 R). The spatial-averaged T{sub e} value increases with the lamp power. The electron density was found to be of the order of 10{sup 21} m{sup -3} which is high at the centre and decreases as r increases. The n{sub e} value also increases with the lamp power. Moreover the results of TS are compared with those from x-ray absorption measurement. The comparison shows that the plasmas in such lamps are not in local thermal equilibrium in the sense that T{sub e} {ne} T-dot{sub g}-gas temperature and locally the rate of ionization is much larger than that of three body recombination.

  13. 201Hg excitation in plasma produced by laser

    International Nuclear Information System (INIS)

    The use of high power lasers allows the study of the properties of matter in extreme conditions of temperature and density. Indeed, the interaction of a power laser and a target creates a plasma in which the temperature is high enough to reach important degrees of ionization. These conditions can allow the excitation of the nucleus. A nucleus of interest to study the processes of nuclear excitation is the 201Hg. This work aims to design an experiment where the 201Hg excitation will be observed in a plasma produced by a high power laser. The first part of this manuscript presents the calculation of the expected nuclear excitation rates in the plasma. For about ten years, nuclear excitation rates have been calculated using the average atom model. To validate this model a code named ADAM (French acronym for Beyond The Average Atom Model) was developed to calculate the nuclear excitation rates under the DCA (Detailed Configuration Accounting) hypothesis. ADAM allows us to deduce the thermo dynamical domain where the nuclear excitation rates determined with the average atom model are relevant. The second part of this manuscript presents the coupling of the excitation rate calculation with a hydrodynamic code to calculate the number of excited nuclei produced in one laser shot for different laser intensity. Finally, in the last part, first experimental approaches which will be used to design an experiment on a laser installation are presented. These approaches are based on the detection and determination of the amount of multicharged ions obtained far from the target (∼80 cm). For this purpose, an electrostatic analyzer was used. (author)

  14. Removal of Cd (II) and Hg(II) by chelating resin Chelex-100

    OpenAIRE

    Afaf Amara-Rekkab; Mohamed Amine Didi

    2015-01-01

    A sensitive, simple method for the determination of amounts of mixture of Hg2+and Cd2+ by spectrophotometry was described based on the formation of the Hg2+- Cd2+- PAN complex in water media. Optimal conditions such as reagent amounts, and pH for the Hg2+- Cd2+ determination were reported. It was found that the 2:1 PAN- Hg2+- Cd2+ complex dominate at pH 13.0. In another hand, the sorption of mixture mercury (II) and cadmium (II) from aqueous medium on a chelating resin Chelex 100 was studied...

  15. Ultrasensitive and selective spectrofluorimetric determination of Hg(II) using a dimercaptothiadiazole fluorophore

    International Nuclear Information System (INIS)

    The present work describes the ultrasensitive and selective spectrofluorimetric determination of Hg(II) using 2,5-dimercaptothiadiazole (DMT) as a fluorophore. DMT shows an emission maximum at 435 nm while exciting at 330 nm. The colorless solution of DMT changes into a highly emittive yellow color immediately after the addition of 0.5 μM Hg(II) and nearly 245-fold increase in emission intensity at 435 nm was observed. These changes were ascribed to the complex formation between Hg(II) and DMT. Based on the fluorescence enhancement, the concentration of Hg(II) was determined. The binding constant value (KA=1.8620x104 mol-1 L) suggests that there is a strong binding force between Hg(II) and DMT. The fluorescence quantum yield of DMT-Hg(II) complex was found to be 4-fold higher than that of DMT, indicating that the DMT-Hg(II) complex was highly emittive than the DMT. Interestingly, the emission intensity was increased even in the presence of 0.1 pM Hg(II). The fluorophore showed an extreme selectivity towards 100 nM Hg(II) in the presence of 50,000-fold higher concentrations of Na+, K+, Ca2+, Mg2+, Fe2+, Fe3+, Cd2+, Cr3+, Mn2+, Zn2+, Co2+, Ni2+, Cl-, SO42-, NO3- ions and 1000-, 500- and 200-fold higher concentrations of Cu2+, Pb2+ and Ag+ ions, respectively, as interferences. The lowest detection of 18 pg L-1 Hg(II) (LOD=3S/m) was achieved for the first time using DMT by fluorimetry. The proposed method was successfully utilized for the determination of Hg(II) in tap water, river water and industrial waste water samples. - Highlights: → 2,5-Dimercpato-1,3,4-thiadiazole was used as a fluorophore for Hg(II) determination. → 245-Fold increase in emission intensity was observed after the addition of 0.5 μM Hg(II). → Using the present method, a detection limit of 18 p Hg(II) was achieved. → Hg(II) was determined in the presence of 50,000-fold concentrations of interferences. → The proposed method was utilized for the determination of Hg(II) in real samples.

  16. Improved limit on the permanent electric dipole moment of 199Hg

    CERN Document Server

    Griffith, W C; Loftus, T H; Romalis, M V; Heckel, B R; Fortson, E N

    2009-01-01

    We report the results of a new experimental search for a permanent electric dipole moment of 199Hg utilizing a stack of four vapor cells. We find d(199Hg) = (0.49 \\pm 1.29_stat \\pm 0.76_syst) x 10^{-29} e cm, and interpret this as a new upper bound, |d(199Hg)| < 3.1 x 10^{-29} e cm (95% C.L.). This result improves our previous 199Hg limit by a factor of 7, and can be used to set new constraints on CP violation in physics beyond the standard model.

  17. Combined in-beam electron and gamma-ray spectroscopy of (184,186)Hg

    CERN Document Server

    Scheck, M; Rahkila, P; Butler, P A; Larsen, A C; Sandzelius, M; Scholey, C; Carrol, R J; Papadakis, P; Jakobsson, U; Grahn, T; Joss, D T; Watkins, H V; Juutinen, S; Bree, N; Cox, D; Huyse, M; Uusitalo, J; Leino, M; Ruotsalainen, P; Nieminen, P; Srebrny, J; Van Duppen, P; Herzan, A; Greenlees, P T; Julin, R; Herzberg, R D; Hauschild, K; Pakarinen, J; Page, R D; Peura, P; Gaffney, L P; Kowalczyk, M; Rinta-Antila, S; Saren, J; Lopez-Martens, A; Sorri, J; Ketelhut, S

    2011-01-01

    By exploiting the SAGE spectrometer a simultaneous measurement of conversion electrons and gamma rays emitted in the de-excitation of excited levels in the neutron-deficient nuclei (184,186)Hg was performed. The light Hg isotopes under investigation were produced using the 4n channels of the fusion-evaporation reactions of (40)Ar and (148,150)Sm. The measured K- and L-conversion electron ratios confirmed the stretched E2 nature of several transitions of the yrast bands in (184,186)Hg. Additional information on the E0 component of the 2(2)(+) -> 2(1)(+) transition in (186)Hg was obtained.

  18. A study of radial cataphoresis and ion densities in high power density Hg-Ar discharges

    Energy Technology Data Exchange (ETDEWEB)

    Aiura, Y; Lawler, J E [Department of Physics, University of Wisconsin, 1150 University Avenue, Madison, WI 53706 (United States)

    2004-11-21

    A synchrotron radiation absorption experiment was used to measure the absolute density of ground level Hg atoms and Hg{sup +} ions in Hg-Ar discharge plasmas at high power densities. Ion densities from this experiment were tested using microwave interferometry and compared with Langmuir probe measurements of the electron density. Radial cataphoresis was observed in this experiment and compared with model predictions. The agreement was satisfactory between the experiment and model. The role of cataphoresis in the power balance of Hg-Ar plasmas was further explored in the research described in the companion paper (Lister et al. 2004 J. Phys. D: Appl. Phys. 37: 3099-3106)

  19. Capability of Catfish (Clarias gariepinus to Accumulate Hg2+ From Water

    Directory of Open Access Journals (Sweden)

    Heny Suseno

    2015-12-01

    Full Text Available Mercury is hazardous contaminant that can be accumulated by aquatic organisms such as fishes, mussels etc. Catfish is one of source of animal protein but it also can accumulate Hg2+ from water that used in aquaculture. Due to less information about capability of catfish to accumulate Hg2+, therefore we studied bioaccumulation of Hg2+ that used biokinetic approach (aqueous uptake-rate, and elimination-rate.  Nuclear application technique was applied in this study by using radiotracer of 203Hg.  A simple kinetic model was then constructed to predict the bioaccumulation capability of   by catfish. The result of experiments were shown that the uptake rate of difference Hg2+ concentration were 79.90 to 101.22 ml.g-1.d-1. Strong correlation between uptake rates with increasing Hg2+concentration. In addition, the elimination rates were range 0.080 – 0.081 day-1. The biology half time (t1/2b of Hg2+ in whole body catfish were 8.50 – 8.63 days.  However, no clear correlation  between elimination rate with increasing concentration of Hg2+. The calculation of Bio Concentration Factor (BCF shown catfish have capability to accumulated Hg maximum 1242.69 time than its concentration in water

  20. Chemical stabilization of 1201-type Hg-Sr based cuprate superconductors

    International Nuclear Information System (INIS)

    The 1201-type Ba-free Hg-Sr based cuprate superconductors with nominal compositions of Hg1-xMoxSr2CuO4+δ(x=0.1-0.25) were synthesized and characterized. The 1201-type structure was stabilized by partial substitution of Mo in the Hg site. A typical composition, Hg0.85Mo0.15 Sr2CuO4+δ crystallizes in tetragonal structure with a=3.769 A and c=8.801 A and a superconducting transition of 57 K was measured. (author)

  1. Rezension zu: Emily Teeter (Hg.), Before the pyramids. The origins of Egyptian civilization

    OpenAIRE

    Köpp-Junk, Heidi

    2013-01-01

    Rezension zu: Emily Teeter (Hg.), Before the Pyramids. The Origins of Egyptian Civilization. The Oriental Institute of the University of Chicago, Oriental Institute Museum Publications 33 (Chicago 2011)

  2. Fabrication, photoemission studies, and sensor of Hg nanoparticles templated on plasmid DNA

    International Nuclear Information System (INIS)

    Fabrication of Hg nanoparticles (NPs) templated on plasmid DNA has been investigated here. The Hg NPs get embedded inside the DNA scaffold through local melting of double helix due to the strong and exclusive interaction of the NPs with the nitrogen of the nucleic acid bases. The interaction of the Hg NPs with the guanine-cytosine base pair sites is responsible for the formation of two Hg metal-base complexes that can find application as the signature of ion-DNA interactions. The modifications in the transport properties of metal conjugated DNA can be utilized as sensor for mercury contamination

  3. Detoxification of selenite and mercury by reduction and mutual protection in the assimilation of both elements by Pseudomonas fluorescens

    International Nuclear Information System (INIS)

    A study on the assimilation and detoxification of selenium and mercury and on the interaction between these two elements was conducted on Pseudomonas fluorescens. P. fluorescens was able to convert separately both elements to their elemental forms, which are less toxic and biologically less available. To study the converting mechanism of selenite to elemental Se, cells were grown in the presence of various selenite concentrations and several parameters such as extracellular protein concentrations, pH, carbohydrate concentrations, isocitrate dehydrogenase (ICDH) and malic enzyme were monitored. Transmission electron microscopy (TEM) and various analytical methods were applied to confirm the interaction between selenium and cell. The former appeared as a red precipitate localized predominantly in the consumed culture medium. P. fluorescens also resisted to the toxic effect of mercury by converting Hg2+ to the volatile and less toxic form Hg . Mercury reductase was likely responsible for the conversion of Hg2+ to Hg . More importantly, the interaction between mercury and selenium was also studied. The presence of selenite significantly reduced the accumulation of mercury in P. fluorescens. It was also interesting to note that mercury appeared to behave as a protecting agent against selenium intoxication as the bioaccumulation of Se was also inhibited by this metal. The formation of Se-Hg complexes could explain this mutual protective effect. No precipitate of elemental Se could be detected when Hg was present in the cultures

  4. Mechanistic understanding of MeHg-Se antagonism in soil-rice systems: the key role of antagonism in soil

    Science.gov (United States)

    Wang, Yongjie; Dang, Fei; Evans, R. Douglas; Zhong, Huan; Zhao, Jiating; Zhou, Dongmei

    2016-01-01

    Methylmercury (MeHg) accumulation in rice has great implications for human health. Here, effects of selenium (Se) on MeHg availability to rice are explored by growing rice under soil or foliar fertilization with Se. Results indicate that soil amendment with Se could reduce MeHg levels in soil and grain (maximally 73%). In contrast, foliar fertilization with Se enhanced plant Se levels (3-12 folds) without affecting grain MeHg concentrations. This evidence, along with the distinct distribution of MeHg and Se within the plant, demonstrate for the first time that Se-induced reduction in soil MeHg levels (i.e., MeHg-Se antagonism in soil) rather than MeHg-Se interactions within the plant might be the key process triggering the decreased grain MeHg levels under Se amendment. The reduction in soil MeHg concentrations could be mainly attributed to the formation of Hg-Se complexes (detected by TEM-EDX and XANES) and thus reduced microbial MeHg production. Moreover, selenite and selenate were equally effective in reducing soil MeHg concentrations, possibly because of rapid changes in Se speciation. The dominant role of Se-induced reduction in soil MeHg levels, which has been largely underestimated previously, together with the possible mechanisms advance our mechanistic understanding about MeHg dynamics in soil-rice systems.

  5. Assessment of the content of mercury, methylmercury and other elements of interest in fish, hair and diets of pre-school children of the Amazon region

    International Nuclear Information System (INIS)

    Studies show that some regions of the Amazon region suffer mercury (Hg) impacts as a direct result of both natural and anthropogenic processes. Jau National Park (PNJ) is the only National Park in Brazil that protects an entire black water basin (Jau River), flood land and tropical reserve. These conditions favor Hg methylation in the aquatic biota. This in turn, exposes living on the river populations to Hg contamination as well as the adjacent regions. Preliminary studies of pre-school children diets from PNJ communities have shown that these diets have a worrisome high Hg content. The present study assessed total Hg content, micro nutrients (Ca, Fe, K, Na, Se and Zn) and macro nutrients (proteins, lipids, ash, energy, carbohydrate) in pre-school diets in the PNJ and surrounding communities. Furthermore, total and Me Hg levels were also determined in hair samples of these children as well as those living in several neighborhoods of the city of Manaus. Included in this determination were the fish most consumed by these populations. From these results it was possible to evaluate the nutritional content of the diets and the exposure of the children to Hg and Se Hg. Cold vapor atomic absorption spectrometry was used to quantify total and Me Hg. Micro nutrient determination was performed using neutron activation analysis technique (NAA) and Macro nutrient through AOAC methodologies (USA). All analytical methods were developed and validated for precision and accuracy by means of reference materials analyses with certified values for the determined elements. Furthermore, the uncertainty sources for Hg and Me Hg determination were assessed and the expanded uncertainties were calculated. Total Hg levels in diets and total and Me Hg levels for hair samples, were well above those values found in different localities of the Amazon region. This also holds true for those surrounding areas of the JNP. For many children Hg intake values passed the 5 mug Hg/body weigh/week (PTWI

  6. Trace elements in two odontocete species (Kogia breviceps and Globicephala macrorhynchus) stranded in New Caledonia (South Pacific)

    International Nuclear Information System (INIS)

    Trace elements in whales on New Caledonia beaches are below levels for concern. - Liver, muscle and blubber tissues of two short-finned pilot whales (Globicephala macrorhynchus) and two pygmy sperm whales (Kogia breviceps) stranded on the coast of New Caledonia have been analysed for 12 trace elements (Al, Cd, Co, Cr, Cu, Fe, organic and total Hg, Mn, Ni, Se, V, and Zn). Liver was shown to be the most important accumulating organ for Cd, Cu, Fe, Hg, Se, and Zn in both species, G. macrorhynchus having the highest Cd, Hg, Se and Zn levels. In this species, concentrations of total Hg are particularly elevated, reaching up to 1452 μg g-1 dry wt. Only a very low percentage of the total Hg was organic. In both species, the levels of Hg are directly related to Se in liver. Thus, a molar ratio of Hg:Se close to 1.0 was found for all specimens, except for the youngest K. breviceps. Our results suggest that G. macrorhynchus have a physiology promoting the accumulation of high levels of naturally occurring toxic elements. Furthermore, concentrations of Ni, Cr and Co are close to or below the detection limit in the liver and muscles of all specimens. This suggests that mining activity in New Caledonia, which typically elevates the levels of these contaminants in the marine environment, does not seem to be a significant source of contamination for these pelagic marine mammals

  7. Brewster angle reflection measurements of Hg density and laser deflection (Schlieren) measurements of Hg density gradients in an ultra-high pressure arc lamp

    International Nuclear Information System (INIS)

    A Brewster angle reflection measurement is used to determine the Hg vapor density at the arc tube wall of an ultra-high pressure lamp. The density measurement in combination with the wall temperature yields a pressure of 201 ± 11 bar. This lamp pressure in combination with an arc core temperature measurement yields an arc core Hg vapor density of 1.78 x 1020 cm-3, which agrees with the density from resonance collisional line broadening measurements of the 1014 nm Hg line. These density results are combined with Abel inverted laser deflection or schlieren measurements to determine a density/temperature map of the Hg vapor in the lamp. The laser deflection technique is sensitive in the arc core and mantle, unlike emission techniques which are sensitive only in the arc core.

  8. Brewster angle reflection measurements of Hg density and laser deflection (Schlieren) measurements of Hg density gradients in an ultra-high pressure arc lamp

    Energy Technology Data Exchange (ETDEWEB)

    Kane, J; Kato, M; Lawler, J E [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States)

    2009-05-01

    A Brewster angle reflection measurement is used to determine the Hg vapor density at the arc tube wall of an ultra-high pressure lamp. The density measurement in combination with the wall temperature yields a pressure of 201 {+-} 11 bar. This lamp pressure in combination with an arc core temperature measurement yields an arc core Hg vapor density of 1.78 x 10{sup 20} cm{sup -3}, which agrees with the density from resonance collisional line broadening measurements of the 1014 nm Hg line. These density results are combined with Abel inverted laser deflection or schlieren measurements to determine a density/temperature map of the Hg vapor in the lamp. The laser deflection technique is sensitive in the arc core and mantle, unlike emission techniques which are sensitive only in the arc core.

  9. Shape coexistence in neutron-deficient Hg isotopes studied via lifetime measurements in $^{184,186}$Hg and two-state mixing calculations

    CERN Document Server

    Gaffney, L P; Page, R.D.; Grahn, T.; Scheck, M.; Butler, P.A.; Bertone, P.F.; Bree, N.; Carroll, R.J.; Carpenter, M.P.; Chiara, C.J.; Dewald, A.; Filmer, F.; Fransen, C.; Huyse, M.; Janssens, R.V.F.; Joss, D.T.; Julin, R.; Kondev, F.G.; Nieminen, P.; Pakarinen, J.; Rigby, S.V.; Rother, W.; Van Duppen, P.; Watkins, H.V.; Wrzosek-Lipska, K.; Zhu, S.

    2014-01-01

    The neutron-deficient mercury isotopes, $^{184,186}$Hg, were studied with the Recoil Distance Doppler Shift (RDDS) method using the Gammasphere array and the K\\"oln Plunger device. The Differential Decay Curve Method (DDCM) was employed to determine the lifetimes of the yrast states in $^{184,186}$Hg. An improvement on previously measured values of yrast states up to $8^{+}$ is presented as well as first values for the $9_{3}$ state in $^{184}$Hg and $10^{+}$ state in $^{186}$Hg. $B(E2)$ values are calculated and compared to a two-state mixing model which utilizes the variable moment of inertia (VMI) model, allowing for extraction of spin-dependent mixing strengths and amplitudes.

  10. Influence of gas components on the oxidation of elemental mercury by positive pulsed corona discharge

    Energy Technology Data Exchange (ETDEWEB)

    Ko, KB.; Byun, Y.; Cho, M.; Namkung, W.; Hamilton, I.P.; Shin, D.N.; Koh, D.J.; Kim, K.T. [Research Institute for Industrial Science and Technology, Pohang (Republic of Korea)

    2008-07-01

    This study examines the effect of flue gas components on the oxidation of gaseous elemental mercury (Hg{sup 0}) to Hg{sup O} and HgCl{sub 2} via pulsed corona discharge (PCD), where the reaction temperature was set to 90 degrees C and the gas stream consisting of 3% H{sub 2}O and 10% O{sub 2} in N{sub 2} was mixed with 45 mu g m{sup -3} Hg{sup 0}, 108 ppm NOx, 80 ppm HCl, 200 ppm SO{sub 2} and 470 ppm NH{sub 3}. It has been observed that O{sub 2} and HCl components in the gas stream act as oxidizing precursors through the generation of oxidizing species (O, O{sub 3}, Cl and Cl{sub 2}) in the PCD process. The presence of NO directly hampers Hg{sup 0} oxidation to Hg{sup O} due to preferential reaction of NO with O and O{sub 3}. In contrast, the presence of SO{sub 2} indirectly influences the oxidation of Hg{sup 0} to HgCl{sub 2} through the fast reaction of SO{sub 2} with OH radical, resulting in consuming OH radicals which are partially responsible for the formation of chlorine species, I. e. Cl and Cl{sub 2}. It has been also found that NH{sub 3} component significantly hinders the oxidation of Hg{sup 0} to HgCl{sub 2} through the fast acid-base reaction with HCl.

  11. Elemental composition of human and animal milk

    International Nuclear Information System (INIS)

    A review is presented of the elemental composition of human and animal milk with special reference to trace elements determined through nuclear techniques, particularly neutron activation analysis (NAA). In the joint IAEA/WHO research project, 16 of the 24 elements under investigation have been analysed by NAA with the aid of advanced research nuclear reactors. Literature data are discussed and tabulated in 50 separate tables (one for each element) mainly for the period after 1950. Each table uses a standard format comprising 10 columns indicating (1) source of milk (e.g. human or animal), (2) status of the milk (colostrum, transitional or mature), (3) country of origin, (4) year of data publication, (5) mean concentration, (6) range of single values or standard deviation of the mean, (7) number of samples analysed, (8) analytical technique employed, (9) literature source of the data, and (10) relevant remarks, if any. The most abundant data refer to the minor elements Ca, Cl, K, Mg, N, Na, P and S and to the trace elements Cu, Fe and Zn. Fewer data are available for Cd, Hg, I, Mn, Pb and Se. For the remaining elements, including such biologically important trace elements as As, Co, Cr, F, Mo, Ni, Si and Sn, very few reliable data so far appear to exist

  12. Toxic metal dispersion in mining areas: from point source to diffusion pollution. The case of the Mt. Amiata Hg mining district (Southern Tuscany - Italy): new results.

    Science.gov (United States)

    Colica, Antonella; Chiarantini, Laura; Rimondi, Valentina; Benvenuti, Marco; Costagliola, Pilario; Lattanzi, Pierfranco; Paolieri, Mario; Rinaldi, Massimo

    2016-04-01

    Rivers draining mining areas may contribute to the diffusion of contaminants through their dispersion and accumulation into different morphological river units. The Paglia River's catchment (southern Tuscany) hosts the SE portion of the Mt. Amiata mercury district, the third most important worldwide (exploited from 1880 to 1980 with a total production of 100,000 tonnes Hg) before becoming a tributary of the Tiber River, which directly flows into Mediterranean Sea. The goals of this study are: 1) to recognize and distinguish different morphological units along the Paglia River watercourse, 2) to determine spatial/temporal distribution and concentration of Hg (and other toxic elements, particularly As) in different units. The analysis of morphological units was made by mapping their evolution from the beginning of mining activity (1883) to present day along 43 km of the Paglia watercourse defining eleven morphological sections across this river, and one across one of its tributaries, the Siele Creek, which drains various Hg mines located upstream. Four fundamental morphological/sedimentary unit types have been distinguished: stream sediments, bar, floodplain, and terraces. The latter occur in various orders and age: Pleistocenic, pre-mining (i.e., dating before 1880), and coeval to the mining activity. A total of 100 samples were taken from the various units in the selected transects, georeferenced and then analyzed for their Hg and As contents by ICP-OES. Arsenic contents generally never exceed 10 mg/kg. The observed ranges are: stream sediments 4.1÷8.2 mg/kg; bars 4.1÷6.6 mg/kg; floodplains 3.8÷6.6 mg/kg; terrace coeval with mining activity 3.2÷10.1 mg/kg. Hg contents in present-day stream sediments and bars are extremely variable (0.2÷27.5 and 1.4÷22.4 mg/kg respectively), and show a sharp increase at the confluence with Siele Creek. Floodplain sediments may reach up to 98 mg/kg. Terraces coeval with mining activity also show variable Hg contents (0.1÷66

  13. Elevated blood Hg at recommended seafood consumption rates in adult seafood consumers.

    Science.gov (United States)

    Karimi, Roxanne; Silbernagel, Susan; Fisher, Nicholas S; Meliker, Jaymie R

    2014-09-01

    Mercury (Hg) exposure from seafood continues to be a public health concern due to health effects from elevated exposure, increasing worldwide seafood consumption, and continued Hg inputs into the environment. Elevated Hg exposure can occur in populations with specialized diets of sport-caught freshwater fish. However, we need a better understanding of Hg exposure from seafood, the most common exposure source, and from specific seafood types. We examined Hg exposure in avid seafood consumers, and the seafood items and consumption frequency that confer the largest Hg exposure. Adult, avid seafood consumers, in Long Island, NY, USA, with blood total Hg concentrations predicted to exceed the USEPA reference concentration that is considered safe (5.8 μg L(-1)), were eligible for the study; 75% of self-reported avid seafood consumers were eligible to participate. We measured blood total Hg concentrations and seafood consumption in 285 participants. We examined relationships between Hg and seafood consumption using multiple linear regression. Seafood consumption rate for our population (14.4 kg yr(-1)) was >2 times that estimated for the U.S. (6.8 kg yr(-1)), and lower than the worldwide estimate (18.4 kg yr(-1)). Mean blood Hg concentration was 4.4 times the national average, and 42% of participants had Hg concentrations exceeding 5.8 μg L(-1). Elevated Hg exposures occurred at all seafood consumption frequencies, including the recommended frequency of 2 meals per week. Blood Hg concentrations were positively associated with weekly tuna steak or sushi intake (β=6.30 change in blood Hg, μg L(-1)) and monthly (β=2.54) or weekly (β=9.47) swordfish, shark or marlin intake. Our findings show that seafood consumers in this population have elevated Hg exposures even at relatively low seafood consumption rates that are at or below current dietary recommendations. Further study should examine health risks and benefits of avid seafood consumption, and consider modifying

  14. Investigation of magnetoabsorption at different temperatures in HgTe/CdHgTe quantum-well heterostructures in pulsed magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Platonov, V. V.; Kudasov, Yu. B.; Makarov, I. V.; Maslov, D. A.; Surdin, O. M. [Sarov Physical–Technical Institute—National Research Nuclear University MEPhI (Russian Federation); Zholudev, M. S.; Ikonnikov, A. V.; Gavrilenko, V. I. [Russian Academy of Sciences, Institute of Physics of Microstructures (Russian Federation); Mikhailov, N. N.; Dvoretsky, S. A. [Russian Academy of Sciences, Rzhanov Institute of Semiconductor Physics, Siberian Branch (Russian Federation)

    2015-12-15

    The magnetoabsorption in magnetic fields as high as 40 T is investigated at T > 77 K in HgTe/CdHgTe quantum-well heterostructures (d{sub QW} ≈ 8 nm). The spectra reveal two lines associated both with intraband transition from the lower Landau level in the conduction band and with interband transition. It is shown that the band structure in these systems changes from inverted to normal with increasing temperature.

  15. HgTe and CdTe epitaxial layers and HgTe–CdTe superlattices grown by laser molecular beam epitaxy

    OpenAIRE

    Cheung, J. T.; Niizawa, G.; Moyle, J.; Ong, N. P.; Paine, B. M.; Vreeland, T., Jr.

    1986-01-01

    CdTe and HgTe epilayers and HgTe/CdTe superlattices have been grown by laser molecular beam epitaxy (laser MBE) on CdTe substrates. The power density of the laser radiation used to evaporate source materials was found to be a very important growth parameter. The superlattice structures have been characterized by helium ion backscattering spectrometry, x-ray double crystal diffractometry, and low temperature electrical transport measurements. Results indicate good crystallinity and very strong...

  16. Detection of non stoichiometric vacancy defects in CdTe, HgTe and Hg1-xCdxTe by positron annihilation

    International Nuclear Information System (INIS)

    Native vacancies are evidenced from positron lifetime measurements in as-grown CdTe, HgTe and Hg0.8Cd0.2Te. The positron lifetime depends on the conducting type of the materials rather than on the growing conditions. The native vacancies have two levels of ionisation and are identified as Cd-vacancies (VCd) in CdTe. (author) 2 figs., 2 tabs., 9 refs

  17. PIXE micro-mapping of minor elements in Hypatia, a diamond bearing carbonaceous stone from the Libyan Desert Glass area, Egypt: Inheritance from a cold molecular cloud?

    Science.gov (United States)

    Andreoli, M. A. G.; Przybylowicz, W. J.; Kramers, J.; Belyanin, G.; Westraadt, J.; Bamford, M.; Mesjasz-Przybylowicz, J.; Venter, A.

    2015-11-01

    Matter originating from space, particularly if it represents rare meteorite samples, is ideally suited to be studied by Particle Induced X-ray Emission (PIXE) as this analytical technique covers a broad range of trace elements and is per se non-destructive. We describe and interpret a set of micro-PIXE elemental maps obtained on two minute (weighing about 25 and 150 mg), highly polished fragments taken from Hypatia, a controversial, diamond-bearing carbonaceous pebble from the SW Egyptian desert. PIXE data show that Hypatia is chemically heterogeneous, with significant amounts of primordial S, Cl, P and at least 10 elements with Z > 21 (Ti, V, Cr, Mn, Fe, Ni, Os, Ir) locally attaining concentrations above 500 ppm. Si, Al, Ca, K, O also occur, but are predominantly confined to cracks and likely represent contamination from the desert environment. Unusual in the stone is poor correlation between elements within the chalcophile (S vs. Cu, Zn) and siderophile (i.e.: Fe vs. Ni, Ir, Os) groups, whereas other siderophiles (Mn, Mo and the Platinum group elements (PGEs)) mimic the distribution of lithophile elements such as Cr and V. Worthy of mention is also the presence of a globular domain (Ø ∼ 120 μm) that is C and metals-depleted, yet Cl (P)-enriched (>3 wt.% and 0.15 wt.% respectively). While the host of the Cl remains undetermined, this chemical unit is enclosed within a broader domain that is similarly C-poor, yet Cr-Ir rich (up to 1.2 and 0.3 wt.% respectively). Our data suggest that the pebble consists of shock-compacted, primitive carbonaceous material enriched in cold, pre-solar dust.

  18. Colorimetric and fluorescent sensor for selective sensing of Hg2+ ions in semi aqueous medium

    International Nuclear Information System (INIS)

    A highly sensitive and selective detection of Hg2+ ion with simple salophen probe was developed. In DMSO: water (40:60, v/v) solution, Hg2+ ions coordinate with imine and shows color turn-off from yellow to colorless. Receptor 1 showed its ability for sensing Hg2+ cations sensitively through three channels: colorimetric, UV–vis and fluorescence spectroscopy. Hg2+ ions coordinate to the imine (Receptor 1) through NONO binding site forming 1:1 complex. It exhibits fluorescent 'Turn-on' behavior based on solvent polarity. The detection limit of our receptor with mercury is 1 μg L−1. -- Graphical abstract: A highly sensitive and rapid detection of Hg2+ with simple salophen probe was developed. In DMSO: water (40:60, v/v) solution, Hg2+ ions coordinate with imine and shows color turn-off from yellow to colorless. Receptor 1 showed its ability for sensing Hg2+ cations sensitively through three channels: colorimetric, UV–vis and Fluorescence Spectroscopy. Hg2+ ions coordinate to the imine (Receptor 1) through the NONO binding site forming 1:1 complex. It exhibits fluorescent 'Turn-on' behavior based on solvent polarity. The detection limit of our receptor with mercury is 1 μg L−1. Highlights: ► Hg2+ ions coordinate with imine and shows color turn-off from yellow to colorless. ► The binding constant of the receptor 1 (DMSO) with Hg2+ ion (DMSO) is 1.35×105. ► Hg2+ ions coordinate to the imine through NONO binding site forming 1:1 complex. ► The receptor 1 shows fluorescent 'Turn-on' behavior based on solvent polarity. ► The detection limit of receptor 1 with mercury is 1 μg L−1

  19. Microsolvation of methylmercury: structures, energies, bonding and NMR constants ((199)Hg, (13)C and (17)O).

    Science.gov (United States)

    Flórez, Edison; Maldonado, Alejandro F; Aucar, Gustavo A; David, Jorge; Restrepo, Albeiro

    2016-01-21

    Hartree-Fock (HF) and second order perturbation theory (MP2) calculations within the scalar and full relativistic frames were carried out in order to determine the equilibrium geometries and interaction energies between cationic methylmercury (CH3Hg(+)) and up to three water molecules. A total of nine structures were obtained. Bonding properties were analyzed using the Quantum Theory of Atoms In Molecules (QTAIM). The analyses of the topology of electron densities reveal that all structures exhibit a partially covalent HgO interaction between methylmercury and one water molecule. Consideration of additional water molecules suggests that they solvate the (CH3HgOH2)(+) unit. Nuclear magnetic shielding constants σ((199)Hg), σ((13)C) and σ((17)O), as well as indirect spin-spin coupling constants J((199)Hg-(13)C), J((199)Hg-(17)O) and J((13)C-(17)O), were calculated for each one of the geometries. Thermodynamic stability and the values of NMR constants correlate with the ability of the system to directly coordinate oxygen atoms of water molecules to the mercury atom in methylmercury and with the formation of hydrogen bonds among solvating water molecules. Relativistic effects account for 11% on σ((13)C) and 14% on σ((17)O), which is due to the presence of Hg (heavy atom on light atom, HALA effect), while the relativistic effects on σ((199)Hg) are close to 50% (heavy atom on heavy atom itself, HAHA effect). J-coupling constants are highly influenced by relativity when mercury is involved as in J((199)Hg-(13)C) and J((199)Hg-(17)O). On the other hand, our results show that the values of NMR constants for carbon and oxygen, atoms which are connected through mercury (C-HgO), are highly correlated and are greatly influenced by the presence of water molecules. Water molecules introduce additional electronic effects to the relativistic effects due to the mercury atom. PMID:26670708

  20. Particulate contacts to Si and CdTe: Al, Ag, Hg-Cu-Te, and Sb-Te

    Science.gov (United States)

    Schulz, Douglas L.; Ribelin, Rosine; Curtis, Calvin J.; Ginley, David S.

    1999-03-01

    Our team has been investigating the use of particle-based contacts in both Si and CdTe solar cell technologies. First, in the area of contacts to Si, powders of Al and Ag prepared by an electroexplosion process have been characterized by transmission electron microscopy (TEM), TEM elemental determination X-ray spectroscopy (TEM-EDS), and TEM electron diffraction (TEM-ED). These Al and Ag particles were slurried and tested as contacts to p- and n-type silicon wafers, respectively. Linear current-voltage (I-V) was observed for Ag on n-type Si, indicative of an ohmic contact, whereas the Al on p-type Si sample was non-ideal. A wet-chemical surface treatment was performed on one Al sample and TEM-EDS indicated a substantial decrease in the O contaminant level. The treated Al on p-type Si films exhibited linear I-V after annealing. Second, in the area of contacts to CdTe, particles of Hg-Cu-Te and Sb-Te have been applied as contacts to CdTe/CdS/SnO2 heterostructures prepared by the standard NREL protocol. First, Hg-Cu-Te and Sb-Te were prepared by a metathesis reaction. After CdCl2 treatment and NP etch of the CdTe layer, particle contacts were applied. The Hg-Cu-Te contacted cells exhibited good electrical characteristics, with Voc>810 mV and efficiencies > 11.5% for most cells. Although Voc>800 mV were observed for the Sb-Te contacted cells, efficiencies in these devices were limited to 9.1% presumably by a large series resistance (>20 Ω) observed in all samples.

  1. Modification and characterization of PET fibers for fast removal of Hg(II), Cu(II) and Co(II) metal ions from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Monier, M., E-mail: monierchem@yahoo.com [Chemistry Department, Faculty of Science, Mansoura University, Mansoura (Egypt); Abdel-Latif, D.A. [Chemistry Department, Faculty of Science, Mansoura University, Mansoura (Egypt)

    2013-04-15

    Highlights: ► PET fibers were graft copolymerized with acrylonitrile. ► Further modification was carried out through the reaction with hydrazine hydrate and then potassium thiocyanate. ► The resulted chelating fibers were characterized by various instrumental methods. ► The fibers were applied to remove Hg{sup 2+}, Cu{sup 2+} and Co{sup 2+} from aqueous solutions. -- Abstract: A new chelating fiber (PET-TSC) was prepared with PET for fast removal of Hg{sup 2+}, Cu{sup 2+} and Co{sup 2+} from water. Elemental analysis, SEM, BET surface area, {sup 13}C NMR, FTIR and X-ray diffraction spectra were used to characterize PET-TSC. The higher uptake capacity of the studied metal ions was observed at higher pH values. Kinetic study indicated that the adsorption of Hg{sup 2+}, Cu{sup 2+} and Co{sup 2+} followed the pseudo-second-order equation, suggesting chemical sorption as the rate-limiting step of the adsorption process. The best interpretation for the equilibrium data was given by Langmuir isotherm, and the maximum adsorption capacities were 120.02, 96.81 and 78.08 mg/g for Hg{sup 2+}, Cu{sup 2+} and Co{sup 2+} ions, respectively. 1 M HCl or 0.1 M EDTA could be used as effective eluant to desorb the Hg{sup 2+}, Cu{sup 2+} and Co{sup 2+} adsorbed by PET-TSC, and the adsorption capacity of PET-TSC for the three heavy metal ions could still be maintained at about 90% level at the 5th cycle. Accordingly, it is expected that PET-TSC could be used as a promising adsorbent for fast removal of heavy metal ions from water, and the present work also might provide a simple and effective method to reuse the waste PET fibers.

  2. Physical properties and band structure of crystals (3HgTe1–x(Al2Te3x, doped with manganese

    Directory of Open Access Journals (Sweden)

    Maryanchuk P. D.

    2014-06-01

    Full Text Available This paper presents the results of the analysis of magnetic, optical, kinetic properties and band parameters of (3HgTe1–x(Al2Te3x crystals doped by manganese. The behavior of the magnetic susceptibility of the (3HgTe1–x(Al2Te3x: crystals can be explained by the presence of Mn—Тe—Mn—Тe clusters or, more precisely, by their transition from a magnetically ordered to a paramagnetic state at Curie temperature Tc. The temperature dependences of electrical conductivity are typical for semiconductor materials. This is due to the increase in carrier concentration with the increase of temperature. The temperature dependence of the Hall coefficient indicates that electrons and holes participate in the transport phenomena in the studied samples (the conductivity is mixed. In (3HgTe1–x(Al2Te3x: crystals, the electron mobility decreases with increasing temperature, indicating the predominance of the scattering of the charge carriers on thermal vibrations of the crystal lattice. Thermoelectric power for the samples under investigation possesses negative values and increases in absolute value with the rise of temperature. The optical band gap of the samples was defined from the optical studies. We have measured current-voltage characteristics of n-TiO2/(3HgTe1–x(Al2Te3x: and n-TiN/(3HgTe1–x(Al2Te3x: heterojunctions at room temperature. The band gap, the matrix element of the interband interaction and the electron effective mass at the bottom of the conduction band were determined from the concentration dependence of the electrons effective mass at the Fermi level.

  3. Biomonitoring of heavy metals (Cd, Hg, and Pb) and metalloid (As) with the Portuguese common buzzard (Buteo buteo).

    Science.gov (United States)

    Carneiro, Manuela; Colaço, Bruno; Brandão, Ricardo; Ferreira, Carla; Santos, Nuno; Soeiro, Vanessa; Colaço, Aura; Pires, Maria João; Oliveira, Paula A; Lavín, Santiago

    2014-11-01

    The accumulation of heavy metals in the environment may have a wide range of health effects on animals and humans. Thus, in this study, the concentrations of arsenic (As), cadmium (Cd), lead (Pb), and mercury (Hg) in the blood and tissues (liver and kidney) of Portuguese common buzzards (Buteo buteo) were determined by inductively coupled plasma-mass spectrometer (ICP-MS) in order to monitor environmental pollution to these elements. In general, Hg and As were the elements which appeared in the highest and lowest concentrations, respectively. A highest percentage of non-detected concentration was found for blood Cd (94.6 %) but, in turn, it was the only metal that was detected in all kidney samples. The kidney was the analyzed sample which showed the highest concentrations of each element evaluated. Statistically, significant differences among blood, liver, and kidney samples were observed for As and Cd (P < 0.05). Cd concentrations in kidney and liver varied significantly with age: Adults showed higher hepatic and renal Cd concentrations than juveniles. Blood Pb concentration seems to show an association with the hunting season. Although raptors are at the top of the food chain and are thus potentially exposed to any biomagnification processes that may occur in a food web, the individuals evaluated in this study generally had low levels of heavy metals in blood and tissues. However, chronic exposure to these metals was verified. The results presented here lend weight to arguments in favor of continuous biomonitoring of metals and metalloids, since heavy metals may accumulate to levels that will pose a risk to both human health and the environment. PMID:25074364

  4. Micromagnetic sensors and Dirac fermions in HgTe heterostructures

    International Nuclear Information System (INIS)

    Within the scope of this thesis two main topics have been investigated: the examination of micromagnetic sensors and transport of massive and massless Dirac fermions in HgTe quantum wells. For the investigation of localized, inhomogeneous magnetic fields, the fabrication and characterization of two different non-invasive and ultra sensitive sensors has been established at the chair ''Experimentelle Physik'' of the University of Wuerzburg. The first sensor is based on the young technique named micro-Hall magnetometry. The necessary semiconductor devices (Hall cross structures) were fabricated by high-resolution electron beam lithography based on two different two dimensional electron gases (2DEGs), namely InAs/(Al,Ga)Sb- and HgTe/(Hg,Cd)Te-heterostructures. The characteristics have been examined in two different ways. Measurements in homogeneous magnetic fields served for characterization of the sensors, whereas the investigation of artificially produced sub-μm magnets substantiates the suitability of the devices for the study of novel nanoscale magnetic materials (e.g. nanowires). Systematic experiments with various magnets are in accordance with the theory of single-domain particles and anisotropic behavior due to shapes with high aspect ratio. The highest sensitivity for strongly localized fields was obtained at T=4.2 K for a (200.200) nm2 Hall cross - made from shallow, high mobility HgTe 2DEG. Although the field resolution was merely δB∼100 μT, the nanoscale sensor size yields an outstanding flux resolution of δΦ=2.10-3 Φ0, where Φ0=h/2e is the flux quantum. Translating this result in terms of magnetic moment, the sensitivity allows for the detection of magnetization changes of a particle centered on top of the sensor as low as δM∼102 μB, with the magnetic moment of a single electron μB, the Bohr magneton. The further examination of a permalloy nanomagnet with a cross-section of (100.20) nm2 confirms the expected resolution ability, extracted from

  5. Micromagnetic sensors and Dirac fermions in HgTe heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Buettner, Bastian

    2012-08-06

    Within the scope of this thesis two main topics have been investigated: the examination of micromagnetic sensors and transport of massive and massless Dirac fermions in HgTe quantum wells. For the investigation of localized, inhomogeneous magnetic fields, the fabrication and characterization of two different non-invasive and ultra sensitive sensors has been established at the chair ''Experimentelle Physik'' of the University of Wuerzburg. The first sensor is based on the young technique named micro-Hall magnetometry. The necessary semiconductor devices (Hall cross structures) were fabricated by high-resolution electron beam lithography based on two different two dimensional electron gases (2DEGs), namely InAs/(Al,Ga)Sb- and HgTe/(Hg,Cd)Te-heterostructures. The characteristics have been examined in two different ways. Measurements in homogeneous magnetic fields served for characterization of the sensors, whereas the investigation of artificially produced sub-{mu}m magnets substantiates the suitability of the devices for the study of novel nanoscale magnetic materials (e.g. nanowires). Systematic experiments with various magnets are in accordance with the theory of single-domain particles and anisotropic behavior due to shapes with high aspect ratio. The highest sensitivity for strongly localized fields was obtained at T=4.2 K for a (200.200) nm{sup 2} Hall cross - made from shallow, high mobility HgTe 2DEG. Although the field resolution was merely {delta}B{approx}100 {mu}T, the nanoscale sensor size yields an outstanding flux resolution of {delta}{Phi}=2.10{sup -3} {Phi}{sub 0}, where {Phi}{sub 0}=h/2e is the flux quantum. Translating this result in terms of magnetic moment, the sensitivity allows for the detection of magnetization changes of a particle centered on top of the sensor as low as {delta}M{approx}10{sup 2} {mu}{sub B}, with the magnetic moment of a single electron {mu}{sub B}, the Bohr magneton. The further examination of a permalloy

  6. Mercury (Hg) in meteorites: variations in abundance, thermal release profile, mass-dependent and mass-independent isotopic fractionation

    CERN Document Server

    Meier, Matthias M M; Marty, Bernard

    2016-01-01

    We have measured the concentration, isotopic composition and thermal release profiles of Mercury (Hg) in a suite of meteorites, including both chondrites and achondrites. We find large variations in Hg concentration between different meteorites (ca. 10 ppb to 14'000 ppb), with the highest concentration orders of magnitude above the expected bulk solar system silicates value. From the presence of several different Hg carrier phases in thermal release profiles (150 to 650 {\\deg}C), we argue that these variations are unlikely to be mainly due to terrestrial contamination. The Hg abundance of meteorites shows no correlation with petrographic type, or mass-dependent fractionation of Hg isotopes. Most carbonaceous chondrites show mass-independent enrichments in the odd-numbered isotopes 199Hg and 201Hg. We show that the enrichments are not nucleosynthetic, as we do not find corresponding nucleosynthetic deficits of 196Hg. Instead, they can partially be explained by Hg evaporation and redeposition during heating of ...

  7. A review on the distribution of Hg in the environment and its human health impacts.

    Science.gov (United States)

    Kim, Ki-Hyun; Kabir, Ehsanul; Jahan, Shamin Ara

    2016-04-01

    Exposure to mercury is a silent threat to the environment and human life. It has the potential to harm almost every organ and body system. Mercury compounds are classified in different chemical types such as elemental, inorganic, and organic forms. The most significant source of ingestion-related mercury exposure in humans and animals is the consumption of fish. Long-term exposure to mercury compounds from different sources (e.g., water, food, soil, and air) can lead to toxic effects on skin, cardiovascular, pulmonary, urinary, gastrointestinal, and neurological systems. Mercury toxicity is found to pose more significant health hazards to certain occupational groups (e.g., goldminers and dental personnel). Because continuous exposure to mercury can be dangerous, it is desirable to re-evaluate the current reference (risk-free) values. This paper reviews the route of Hg exposure to humans, its human health impacts, the associated risk assessment, and treatment based on the recent findings from various studies. PMID:26826963

  8. Coulomb excitation of $^{182-184}$ Hg: Shape coexistence in the neutron-deficient lead region

    CERN Multimedia

    We put forward a study of the interplay between individual nucleon behavior and collective degrees of freedom in the nucleus, as manifested in shape coexistence in the neutrondeficient lead region. As a first step of this experimental campaign, we propose to perform Coulomb excitation on light mercury isotopes to probe their excited states and determine transitional and diagonal E2 matrix elements, especially reducing the current uncertainties. The results from previous Coulomb excitation measurements in this mass region performed with 2.85 MeV/u beams from REX-ISOLDE have shown the feasibility of these experiments. Based on our past experience and the results obtained, we propose a detailed study of the $^{182-184}$Hg nuclei, that exhibit a pronounced mixing between low-lying excited states of 2 apparently different deformation character, using the higher energy beams from HIE-ISOLDE which are crucial to reach our goal. The higher beam energy should result in an increased sensitivity with respect to the quad...

  9. Elemental bioaccumulators in air pollution studies

    International Nuclear Information System (INIS)

    K0-Based instrumental neutron activation analysis (k0 INAA) was used to determine the concentrations of Cr, Fe, Co, Zn, Se, Sb and Hg in the vascular plants Cistus salvifolius and Inula viscosa and in the lichen Parmelia sulcata. The samples were collected in the neighbourhood of industrial complexes. The elemental accumulation in the vascular plants and the lichen are compared to optimize the choice of the bioaccumulator. It is concluded that P.sulcata seems to be the best accumulator of the three species for the element studied; Cistus salvifolius is sensitive to the contents of Zn, Fe, Cr and Sb in the air; Inula viscosa seems to accumulate Fe, Sb, Co, Cr and Zn. Nevertheless, it is concluded that lichen is a good air pollution indicator, while the vascular plants are not due to the large seasonal variations found in the elemental concentrations. (author) 11 refs.; 7 figs.; 2 tabs

  10. Radiographic element

    International Nuclear Information System (INIS)

    Radiographic elements are disclosed comprised of first and second silver halide emulsion layers separated by an interposed support capable of transmitting radiation to which the second image portion is responsive. At least the first imaging portion contains a silver halide emulsion in which thin tubular silver halide grains of intermediate aspect ratios (from 5:1 to 8:1) are present. Spectral sensitizing dye is adsorbed to the surface of the tubular grains. Increased photographic speeds can be realized at comparable levels of crossover. (author)

  11. Viscosity Relaxation in Molten HgZnTe

    Science.gov (United States)

    Baird, James K.

    2002-01-01

    Because of its narrow electronic band-gap, HgZnTe solid solutions have been proposed as effective detectors for infrared radiation. To produce the best single crystals of these materials for this application, knowledge of the phase diagram that governs the freezing of the liquid is essential. Besides the phase diagram, however, some information concerning the thermophysical properties of the melt, such as viscosity, density, specific heat, and enthalpy of mixing, can also be useful. Of these thermophysical properties, the viscosity is perhaps of the most interest scientifically. Measurements using the oscillating cup method have shown that the isothermal melt requires tens of hours of equilibration time before a steady value of the viscosity can be achieved. Over this equilibration time, which depends upon temperature, the viscosity can increase by as much as a factor of two before reaching a steady state. We suggest that this relaxation phenomenon may be due to a slight polymerization of Te atoms in the melt. To account for the time dependence of the viscosity in the HgZnTe melt, we propose that the liquid acts as a solvent that favors the formation of Te atom chains. We suggest that as the melt is cooled from a high temperature to the temperature for measurement of the viscosity, a free radical polymerization of Te atoms begins. To estimate this average molecular weight, we use a simple free radical polymerization mechanism, including a depolymerization step, to calculate the time dependence to the concentration of each Te polymer molecular weight fraction. From these molecular weight fractions, we compute the weight average molecular weight of the distribution. Using the semi-empirical relation between average molecular weight and viscosity, we obtain a formula for the time dependence of the viscosity of the melt. Upon examining this formula, we find that the viscosity achieves a steady value when a balance is achieved between the rate of formation of the chains

  12. Renal Scintiscanning with Hg209-Neohydrin in Urologic Diseases

    International Nuclear Information System (INIS)

    Renal scintiscanning has been carried out using Hg203 - labelled Neohydrin. The equipment used is the Nuclear Chicago Isotope Scanner Type 1700 with 2 x 2 - i n crystal and a 7 - cm focal-length honeycomb collimator. Usually the scintigrams are registered both on paper and on photographic film. Hg203 - labelled Neohydrin is usually employed in doses of 120 - 160 μc (about 2 μc/kg). The scanning examination starts about 2 h after the injection and lasts about 40-50 min. The selective storage of labelled Neohydrin at the level of the renal cortex makes it possible to obtain a graphic representation of the two kidneys and to identify their position, orientation and shape, and the homogeneity of the actively functioning parenchyma. In some cases, autoradiographic investigations have been carried out on diseased kidneys after surgical removal. By this method anomalies in position and orientation, both congenital and acquired, can be ascertained. As regards shape, the limits of the renal patterns are the mote clearly defined as the renal function is better. Technical aspects such as the width of the crystal, type of collimator (whose focal plane should pass through the transverse medial plane of the kidneys), and dose - which should be not too high not too low - are essential conditions for a correct graphic reproduction of the renal patterns. Failure in tabular activity in the parenchyma is shown by a lack in the uptake of radioactivity. The position, extent and shape of such defects in uptake vary according to the entity of the renal structures and their derangement due to various pathological processes: tumours, cysts, hydronephrosis, tuberculosis etc. In normal subjects a homogeneous scintigram is usual, although a clearer hilar region is not a rare occurrence. Any circumscribed decrease of scintigraphic density outside the hilum is the expression of a less actively functioning zone. Among kidney patterns larger than normal, the homogeneous ones which point to a

  13. A measurement of the neutron to 199Hg magnetic moment ratio

    Directory of Open Access Journals (Sweden)

    S. Afach

    2014-12-01

    Full Text Available The neutron gyromagnetic ratio has been measured relative to that of the 199Hg atom with an uncertainty of 0.8 ppm. We employed an apparatus where ultracold neutrons and mercury atoms are stored in the same volume and report the result γn/γHg=3.8424574(30.

  14. Influence of Ga and Hg on microstructure and electrochemical corrosion behavior of Mg alloy anode materials

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The effects of Hg and Ga on the electrochemical corrosion behavior of Mg-5%Hg (molar fraction) alloys were investigated by the measurement of polarization curves and galvanostatic test. The microstructure of the alloys and the corroded surface of the specimens were investigated by scanning electron microscopy, X-ray diffractometry and emission spectrum analysis. It can be concluded that the addition of 1%Ga (molar fraction) reduces corrosion current density from 26.98 mA/cm2 to 2.34 mA/cm2;while the addition of 1%Hg (molar fraction) increases corrosion current density. The addition of Ga and Hg both promotes the electrochemical activity of the alloys and the influence of Ga is more effective than Hg. Mg-5%Hg-1%Ga alloy has the best electrochemical activity, showing mean potential of-1.992 V. The activation mechanism of the magnesium alloy produced by Hg and Ga was put forward. Magnesium atoms are dissolved in liquid Hg and Ga to form amalgam and undergo severe oxidation at the amalgam/electrolyte interface.

  15. Electrodeposited CdTe and HgCdTe solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Basol, B.M.

    1988-01-15

    The processing steps necessary for producing high efficiency electrodeposited CdTe and HgCdTe solar cells are described. The key step in obtaining solar cell grade p-type CdTe and HgCdTe is the 'type conversion-junction formation' (TCJF) process. The TCJF process involves the heat treatment of the as-deposited n-type CdTe and HgCdTe layers at around 400 /sup 0/C. This procedure converts these n-type films into high resistivity p type and forms a rectifying junction between them and the underlying n-type window layers. Possible effects of oxygen on the TCJF process are discussed. The results of studies made on the structural, electrical and optical properties of the electrodeposited CdS, CdTe and HgCdTe films are presented. The resistivity of the electrodeposited HgCdTe can be made lower than that of CdTe. Consequently, solar cells made using the HgCdTe films have, on the average, better fill factors than those made using the CdTe layers, HgCdTe is also attractive for tandem-cell applications because of its variable band gap which can be easily tuned to the desired value. CdS/CdTe and CdS/HgCdTe heterojunction solar cells with 10.3% and 10.6% efficiency have been demonstrated using electrodeposition techniques and the TCJF process.

  16. 40 CFR 75.83 - Calculation of Hg mass emissions and heat input rate.

    Science.gov (United States)

    2010-07-01

    ... heat input rate. 75.83 Section 75.83 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Calculation of Hg mass emissions and heat input rate. The owner or operator shall calculate Hg mass emissions and heat input rate in accordance with the procedures in sections 9.1 through 9.3 of appendix F...

  17. A measurement of the neutron to 199Hg magnetic moment ratio

    CERN Document Server

    Afach, S; Ban, G; Bison, G; Bodek, K; Burghoff, M; Chowdhuri, Z; Daum, M; Fertl, M; Franke, B; Geltenbort, P; Green, K; van der Grinten, M G D; Grujic, Z; Harris, P G; Heil, W; Hélaine, V; Henneck, R; Horras, M; Iaydjiev, P; Ivanov, S N; Kasprzak, M; Kermaïdic, Y; Kirch, K; Knecht, A; Koch, H -C; Krempel, J; Kuźniak, M; Lauss, B; Lefort, T; Lemière, Y; Mtchedlishvili, A; Naviliat-Cuncic, O; Pendlebury, J M; Perkowski, M; Pierre, E; Piegsa, F M; Pignol, G; Prashanth, P N; Quéméner, G; Rebreyend, D; Ries, D; Roccia, S; Schmidt-Wellenburg, P; Schnabel, A; Severijns, N; Shiers, D; Smith, K F; Voigt, J; Weis, A

    2014-01-01

    The neutron gyromagnetic ratio has been measured relative to that of the 199Hg atom with an uncertainty of 0.8 ppm. We employed an apparatus where ultracold neutrons and mercury atoms are stored in the same volume and report the result $\\gamma_{\\rm n}/\\gamma_{\\rm Hg} = 3.8424574(30)$.

  18. Crystal structure and transport properties of Pd5HgSe

    Czech Academy of Sciences Publication Activity Database

    Laufek, F.; Vymazalová, A.; Drábek, M.; Navrátil, Jiří; Plecháček, T.; Drahokoupil, Jan

    2012-01-01

    Roč. 14, č. 10 (2012), s. 1476-1479. ISSN 1293-2558 R&D Projects: GA ČR GAP108/10/1315 Institutional support: RVO:61389013 ; RVO:68378271 Keywords : Pd5HgSe * Pd-Hg-Se system * crystal structure Subject RIV: CA - Inorganic Chemistry Impact factor: 1.671, year: 2012

  19. Frequency Ratio of ${}^{199}$Hg and ${}^{87}$Sr Optical Lattice Clocks beyond the SI Limit

    CERN Document Server

    Yamanaka, Kazuhiro; Ushijima, Ichiro; Takamoto, Masao; Katori, Hidetoshi

    2015-01-01

    We report on a frequency ratio measurement of a ${}^{199}$Hg-based optical lattice clock referencing a ${}^{87}$Sr-based clock. Evaluations of lattice light shift, including atomic-motion-dependent shift, enable us to achieve a total systematic uncertainty of $7.2 \\times 10^{-17}$ for the Hg clock. The frequency ratio is measured to be $\

  20. Disentangling the nuclear shape coexistence in even-even Hg isotopes using the interacting boson model

    CERN Document Server

    García-Ramos, J E

    2014-01-01

    We intend to provide a consistent description of the even-even Hg isotopes, 172-200Hg, using the interacting boson model including configuration mixing. We pay special attention to the description of the shape of the nuclei and to its connection with the shape coexistence phenomenon.

  1. Cleavable Molecular Beacon for Hg(2+) Detection Based on Phosphorothioate RNA Modifications.

    Science.gov (United States)

    Huang, Po-Jung Jimmy; Wang, Feng; Liu, Juewen

    2015-07-01

    Mercury is a highly toxic heavy metal, and detection of Hg(2+) by biosensors has attracted extensive research interest in the past decade. In particular, a number of DNA-based sensing strategies have been developed. Well-known examples include thymine-Hg(2+) interactions and Hg(2+)-activated DNAzymes. However, these mechanisms are highly dependent on buffer conditions or require hybridization with another DNA strand. Herein, we report a new mechanism based on Hg(2+)-induced cleavage of phosphorothioate (PS) modified RNA. Among the various metal ions tested, Hg(2+) induced the most significant cleavage (∼16%), while other metals cleaved less than 2% of the same substrate. The uncleaved substrate undergoes desulfurization in the presence of Hg(2+). This cleavage reaction yields a similar amount of product from pH 3.5 to 7 and in the temperature range between 20 and 90 °C. Various PS RNA junctions can be cleaved with a similar efficiency, but PS DNA junctions cannot be cleaved. A molecular beacon containing three PS RNA modifications is designed, detecting Hg(2+) down to 1.7 nM with excellent selectivity. This sensor can also detect Hg(2+) in the Lake Ontario water sample, although its response is significantly masked by fish tissues. PMID:26060876

  2. Superheavy elements

    CERN Document Server

    Hofmann, S

    1999-01-01

    The outstanding aim of experimental investigations of heavy nuclei is the exploration of spherical 'SuperHeavy Elements' (SHEs). On the basis of the nuclear shell model, the next double magic shell-closure beyond sup 2 sup 0 sup 8 Pb is predicted at proton numbers between Z=114 and 126 and at neutron number N=184. All experimental efforts aiming at identifying SHEs (Z>=114) were negative so far. A highly sensitive search experiment was performed in November-December 1995 at SHIP. The isotope sup 2 sup 9 sup 0 116 produced by 'radiative capture' was searched for in the course of a 33 days irradiation of a sup 2 sup 0 sup 8 Pb target with sup 8 sup 2 Se projectiles, however, only cross-section limits were measured. Positive results were obtained in experiments searching for elements from 110 to 112 using cold fusion and the 1n evaporation channel. The produced isotopes were unambiguously identified by means of alpha-alpha correlations. Not fission, but alpha emission is the dominant decay mode. The measurement ...

  3. Seasonal and diurnal variations of Hg° over New England

    Directory of Open Access Journals (Sweden)

    J. D. Hegarty

    2008-03-01

    Full Text Available Factors influencing diurnal to interannual variability in Hg° over New England were investigated using multi-year measurements conducted by AIRMAP at the Thompson Farm (TF coastal site, an inland elevated site at Pac Monadnock (PM, and two month measurements on Appledore Island (AI in the Gulf of Maine. Mixing ratios of Hg° at TF showed distinct seasonality with maxima in March and minima in October. Hg° at AI tracked the trend at TF but with higher minima, while at PM the diurnal and annual cycles were dampened. In winter, Hg° was correlated most strongly with CO and NOy, indicative of anthropogenic emissions as their primary source. Our analysis indicates that Hg° had a regional background level of ~160 fmol/mol in winter, a dry deposition velocity of ~0.20 cm s−1 with a ~16 day lifetime in the coastal boundary layer in summer. The influence of oceanic emissions on ambient Hg° levels was identified using the Hg°-CHBr3 correlation at both TF and AI. Moreover, the lower Hg° levels and steeper decreasing warm season trend at TF (0.5–0.6 fmol/mol d−1 compared to PM (0.2–0.3 fmol/mol d−1 likely reflected the impact of marine halogen chemistry. Large interannual variability in warm season Hg° levels in 2004 versus 2005/2006 may be due to the role of precipitation patterns in influencing surface evasion of Hg°. In contrast, changes in wintertime maximum levels of Hg° were small compared to drastic reductions in CO, CO2, NOy, and SO2 from 2004/2005 to 2006/2007. These trends could be explained by a homogeneous distribution of Hg° over North American in winter due to its long lifetime and/or rapid removal of reactive mercury from anthropogenic sources. We caution that during warmer winters, the Hg°-CO slope possibly reflects Hg° loss relative to changes in CO more than their emission ratio.

  4. [Seasonal Variations in Vertical Profile of Hg Species and the Influential Factors in Changshou Reservior].

    Science.gov (United States)

    Bai, Wei-yang; Zhang, Cheng; Tang, Zhen-ya; Zhao, Zheng; Wang, Ding-yong

    2015-10-01

    The vertical distribution of mercury (Hg) species were investigated in water and porewater of Changshou reservoir during the period from September 2013 to July 2014. Water samples were collected seasonally from five sampling sites, and the concentrations of Hg species were evaluated. Diffusion fluxes of Hg from sediment to overlaying water were also obtained. The results showed that the average concentrations of total Hg and total methylmercury (MeHg) were (14.77 ± 12.24) ng x L(-1) and (0.41 ± 0.47) ng x L(1), respectively. The concentrations of dissolved MeHg (DMeHg) was highest in 4-8 m under surface water, and then decreased with the increasing water depth with a subsequent increase in the bottom of Changshou Reservior. Peak particulate MeHg (PMeHg) values were found in 8-20 m under surface water, but not in the interface of sediment-water, suggesting that the increasing PMeHg might be related to the deposition of MeHg adsorbed to particulates from upper water. Two peak MeHg levels in pore water appeared in 16 and 28 cm under sediment surface, probably due to the extension of living region for sulfate reduction bacteria (SRB) to deeper sediment which resulted in increased methylation rate there. The diffusion fluxes of DMeHg from pore water to overlaying water were 28.2 ng x (m2 x d)(1) and 30.0 ng x (m2 x d)(-1) in autumn and summer, which were significantly higher than that in winter 3.8 ng x (m2 x d)(-1). It may be associated with the higher temperature in those two seasons. An obvious negative correlation was observed between DMeHg and dissolved oxygen (DO) in summer and spring (r = -0.482**, P < 0.05; r = -0.339, P < 0.01); however, similar correlations were not found in autumn and winter. PMID:26841596

  5. E2 and M1 Transition Probabilities in Odd Mass Hg Nuclei

    International Nuclear Information System (INIS)

    L- and M-subshell ratios have been measured for the 39.5 keV transition in 193Hg and the 37.1 and 16.2 keV transitions in 195Hg yielding 0.38 ± 0.12 , 193Hg and the 53.3 and 37.1 keV levels in 195Hg have been measured by the delayed coincidence method, yielding values of 0.63 ± 0.03, 0.72 ± 0.03 and <0.05 nsec respectively. A systematic compilation of reduced E2 and M1 transition probabilities in odd mass Pt, Hg and Pb nuclei is given and compared to theoretical predictions

  6. X-ray photoelectron spectroscopic investigations of modifications in plasmid DNA after interaction with Hg nanoparticles

    International Nuclear Information System (INIS)

    The electronic structure of plasmid DNA both prior to and after its conjugation with Hg nanoparticles (NP) has been investigated here. The DNA molecules undergo severe perturbation on their interaction with Hg-NP. The circular plasmid DNA becomes predominantly linearised on interaction with 10 mM Hg salt solution. These perturbations are also reflected in the electronic structure of C1s and O1s suggesting severe modifications in the exocyclic groups, of the nucleic acid bases, participating in the hydrogen bondings. The results reflect the rupturing of the purine-pyrimidine bonds after interaction with the NP. The study also suggests selective and specific interactions of DNA bases with the Hg nanoparticles leading to the formation of metal-purine-pyrimidine complexes through rupturing of G-C base pairs. Hg-NP exclusively interact with the nitrogen bases of the DNA molecule and do not cause any significant modification to the phosphate backbone of DNA.

  7. X-Ray Scattering Studies of HgSe Nanoclusters in Zeolite

    Science.gov (United States)

    Abeykoon, A. M. M.; Castro-Colin, M.; Anokhina, E. V.; Iliev, M. N.; Donner, W.; Brunelli, M.; Jacobson, A. J.; Moss, S. C.

    2008-12-01

    Structural studies done on HgSe nanoclusters fabricated in the pores of two types of zeolite frameworks, LTL (tubular pore) and Nd-Y (nearly spherical pore), are presented. Nanoclusters were synthesized in these zeolite frameworks via chemical vapor deposition. Anomalous X-ray scattering (AXS) studies were performed on both HgSe/zeolite-Y and HgSe/zeolite-L systems. As a result, we present two distinct structural models for NdY/HgSe and LTL/HgSe systems. A remarkable feature present in our X-ray diffraction (XRD) patterns, diffuse scattering, will also be discussed using our initial results of the atomic pair distribution function (PDF) studies. X-ray structural work is complemented using the results of optical and Raman studies.

  8. 199Hg and 63,65Cu NMR studies of mercury based high-Tc superconductors

    International Nuclear Information System (INIS)

    Hg-oxide ceramic high temperature superconductors were studied with 199Hg- and 63,65Cu- NMR spectroscopy. Room temperature spectra, spin-spin and spin-lattice relaxation times of samples with different superconducting transition temperatures are presented. A spin-lattice relaxation time of T1 = 35 msec and a spin-spin relaxation time of T2 = 1.6 msec is found for the 199 Hg-NMR. All samples exhibit similar characteristic powder spectra caused by an axially symmetric 199Hg spin interaction. The isotropic value and the anisotropy of the tensor relative to solid HgCl2 as a standard substance is estimated. Furthermore results of 63,65Cu NMR at a temperature of 4.2 K are presented. Also this signal shows a powder line shape (for I = 3/2)

  9. Synthesis of Starch-Stabilized Ag Nanoparticles and Hg2+Recognition in Aqueous Media

    Directory of Open Access Journals (Sweden)

    Fan Yingju

    2009-01-01

    Full Text Available Abstract The starch-stabilized Ag nanoparticles were successfully synthesized via a reduction approach and characterized with SPR UV/Vis spectroscopy, TEM, and HRTEM. By utilizing the redox reaction between Ag nanoparticles and Hg2+, and the resulted decrease in UV/Vis signal, we develop a colorimetric method for detection of Hg2+ion. A linear relationship stands between the absorbance intensity of the Ag nanoparticles and the concentration of Hg2+ion over the range from 10 ppb to 1 ppm at the absorption of 390 nm. The detection limit for Hg2+ions in homogeneous aqueous solutions is estimated to be ~5 ppb. This system shows excellent selectivity for Hg2+over other metal ions including Na+, K+, Ba2+, Mg2+, Ca2+, Fe3+, and Cd2+. The results shown herein have potential implications in the development of new colorimetric sensors for easy and selective detection and monitoring of mercuric ions in aqueous solutions.

  10. Magnetically recoverable fluorescence chemosensor for the adsorption and selective detection of Hg2+ in water.

    Science.gov (United States)

    Lv, Qiang; Li, Gang; Cheng, Zhuhong; Lu, Hong; Gao, Xiaoxia

    2014-01-01

    In order to conveniently and effectively detect the heavy metal ion Hg(2+) existing in water, a magnetic fluorescence chemosensor has been strategically prepared by immobilizing a Rhodamine B derivative RhB-tris(2-aminoethyl)amine on Fe3O4@SiO2-Au@PSiO2 composites via gold particles. The adsorption and detection for Hg(2+) ions were investigated with fluorophotometry. This chemosensor shows high sensitivity and high selectivity for Hg(2+) over other metal cations owing to the ring opening of the rhodamine fluorophore selectively induced by Hg(2+). In addition, the presence of Fe3O4 in the sensor also facilitates the magnetic separation of the Fe3O4@SiO2-Au-Hg(2+)@PSiO2 from the solution. PMID:24270323

  11. Wading bird guano contributes to Hg accumulation in tree island soils in the Florida Everglades.

    Science.gov (United States)

    Zhu, Yingjia; Gu, Binhe; Irick, Daniel L; Ewe, Sharon; Li, Yuncong; Ross, Michael S; Ma, Lena Q

    2014-01-01

    Tree islands are habitat for wading birds and a characteristic landscape feature in the Everglades. A total of 93 surface soil and 3 soil core samples were collected from 7 degraded/ghost and 34 live tree islands. The mean Hg concentration in surface soils of ghost tree islands was low and similar to marsh soil. For live tree islands, Hg concentrations in the surface head region were considerably greater than those in mid and tail region, and marsh soils. Hg concentrations in bird guano (286 μg kg(-1)) were significantly higher than those in mammal droppings (105 μg kg(-1)) and plant leaves (53 μg kg(-1)). In addition, Hg concentrations and δ(15)N values displayed positive correlation in soils influenced by guano. During 1998-2010, estimated annual Hg deposition by guano was 148 μg m(-2) yr(-1) and ~8 times the atmospheric deposition. PMID:24080244

  12. Infra-red photodiodes in Hg1-xCdxTe grown by OMVPE

    International Nuclear Information System (INIS)

    Hg1-xCdxTe layers, grown by the organometallic vapor phase epitaxy (OMVPE), are p-type with carrier concentrations around 4 x 1016/cm3 due to the Group II vacancies in them. Following a Hg saturated anneal at 220 degrees C, these layers became n-type with carrier concentrations around 4 x 1014/cm3. In order to fabricate p-n junction diodes, Hg1-xCdxTe layers were grown with a 0.5-0.8 μm thick CdTe cap. By opening windows in this CdTe cap, the underlying Hg1-xCdxTe layer was annealed in a selective manner, thus forming planar p-n junctions. The CdTe cap, which is used as the diffusion barrier for Hg during the selective anneal, also served as the junction passivant for the photodiodes. Details of device fabrication and characterization are presented in this paper

  13. Mercury profiles in sediment from the marginal high of Arabian Sea: an indicator of increasing anthropogenic Hg input.

    Science.gov (United States)

    Chakraborty, Parthasarathi; Vudamala, Krushna; Chennuri, Kartheek; Armoury, Kazip; Linsy, P; Ramteke, Darwin; Sebastian, Tyson; Jayachandran, Saranya; Naik, Chandan; Naik, Richita; Nath, B Nagender

    2016-05-01

    Total Hg distributions and its speciation were determined in two sediment cores collected from the western continental marginal high of India. Total Hg content in the sediment was found to gradually increase (by approximately two times) towards the surface in both the cores. It was found that Hg was preferentially bound to sulfide under anoxic condition. However, redox-mediated reactions in the upper part of the core influenced the total Hg content in the sediment cores. This study suggests that probable increase in authigenic and allogenic Hg deposition attributed to the increasing Hg concentration in the surface sediment in the study area. PMID:26797942

  14. Can graphene make better HgCdTe infrared detectors?

    Directory of Open Access Journals (Sweden)

    Shi Yanli

    2011-01-01

    Full Text Available Abstract We develop a simple and low-cost technique based on chemical vapor deposition from which large-size graphene films with 5-10 graphene layers can be produced reliably and the graphene films can be transferred easily onto HgCdTe (MCT thin wafers at room temperature. The proposed technique does not cause any thermal and mechanical damages to the MCT wafers. It is found that the averaged light transmittance of the graphene film on MCT thin wafer is about 80% in the mid-infrared bandwidth at room temperature and 77 K. Moreover, we find that the electrical conductance of the graphene film on the MCT substrate is about 25 times larger than that of the MCT substrate at room temperature and 77 K. These experimental findings suggest that, from a physics point of view, graphene can be utilized as transparent electrodes as a replacement for metal electrodes while producing better and cheaper MCT infrared detectors.

  15. ROIC for HgCdTe e-APD FPA

    Science.gov (United States)

    Chen, Guoqiang; Zhang, Junling; Wang, Pan; Zhou, Jie; Gao, Lei; Ding, Ruijun

    2013-08-01

    Ultra-low light imaging and passive/active dual mode imaging require very low noise optical receivers to achieve detection of fast and weak optical signal. HgCdTe electrons initiated avalanche photodiodes (e-APDs) in linear multiplication mode is the detector of choice thanks to its high quantum efficiency, high gain at low bias, high bandwidth and low noise factor. In my work, a passive/active dual mode readout integrated circuit (ROIC) of e-APD focal plane array (FPA) is designed. Unit cell circuit architecture of ROIC includes a capacitance feedback transimpedance amplifier (CTIA) as preamplifier of ROIC, a high voltage protection module, a comparator, a Sample-Hold circuit module, and output driver stage. There is a protection module in every unit cell circuit which can avoid ROIC to be damaged from avalanche breakdown of some diodes of detector. Conventional 5V CMOS process is applied to implement the high voltage protection with the small area rather than Laterally Diffused Metal Oxide Semiconductor (LDMOS) in high voltage BCD process in the limited 100um×100um pitch area. In CTIA module, three integration capacitances are included in the CTIA module, two of them are switchable to provide different well capacity and noise. Constraints such as pixel area, stability and power lead us design toward a simple one-stage cascade operational transconductance amplifier (OTA) as pre-amplifier. High voltage protection module can protect ROIC to be damaged because of breakdown of some avalanche diodes.

  16. Dislocation reduction in HgCdTe grown on CdTe/Si

    Science.gov (United States)

    Wijewarnasuriya, Priyalal S.

    2016-05-01

    Bulk-grown CdZnTe (Zn = 3%) substrates are the natural choice for HgCdTe epitaxy since it is lattice matched to long wave LW-HgCdTe alloy. However, lack of large area CdZnTe substrates, high production costs, and more importantly, the difference in thermal expansion coefficients between CdZnTe and silicon Read out Integrated Circuits (ROIC) are some of the inherent drawbacks of CdZnTe substrates. Consequently, Hg1-xCdxTe detectors fabricated on silicon substrates are an attractive alternative. Recent developments in the molecular beam epitaxy (MBE) buffer layer growth technology on Si substrates has revolutionized the HgCdTe research and offered a new dimension to HgCdTe-based IR technology. Si substrates provide advantages in terms of relatively large area (3 to 6-inch diameter is easily obtained) compared to CZT substrate materials, durability during processing, and reliability to thermal cycling. Innovations in Si-based composite substrates made it possible to fabricate very large-format IR arrays that offer higher resolution, low-cost arrays and more dies per wafer. Between Si substrates and HgCdTe has large lattice mismatch of 19%. This leads to dislocation densities of low-107 cm-2 for optimal growth of HgCdTe on silicon-based substrates as compared to the mid-104 cm-2 dislocation density of HgCdTe grown on CdZnTe. This paper present dislocation reduction by two orders of magnitude using thermal cycle anneal under Hg environment on HgCdTe grown on Si substrates and as well as defect reduction in Cd(Se)Te buffer layers grown on Si Substrates.

  17. Synthesis and characterization of ZnxHg1-xSeyS1-y quantum dots

    International Nuclear Information System (INIS)

    This article describes the synthesis of highly water-soluble ZnxHg1-xSeyS1-y quantum dots (QDs) in aqueous solution through a simple photo-assisted reaction between ZnSe QDs and mercury(I) nitrate dihydrate [Hg2(NO3)2.2H2O]. In order to deduce the optimal synthesis conditions, we varied several parameters, including the concentrations of mercaptosuccinic acid (MSA) and Hg2(NO3)2.2H2O, the illumination time, and the reaction temperature. When irradiated at temperatures below 80 oC, the ZnSe QDs reacted with the S2- ions formed rapidly from MSA and the Hg2+ ions formed from Hg22+ ions to form ZnxHg1-xSeyS1-y QDs through a process of photo-etching and surface combination. Under different conditions, we prepared a series of ZnxHg1-xSeyS1-y QDs that emit fluorescence at the maximum wavelengths ranging from 405 to 760 nm. Inductively coupled plasma-mass spectrometry and transmission electron microscopy/energy dispersive spectrometry revealed that the content of Hg in the ZnxHg1-xSeyS1-y QDs was greater when the synthesis was conducted at higher temperature. The Zn0.88Hg0.12Se0.44S0.56 QDs exhibit improved photostability than crude ZnSe QDs and possess long lifetimes (τ1 ∼ 38 ns and τ2 ∼ 158 ns).

  18. Reproducible Design for the Optical Screening and Sensing of Hg(II Ions

    Directory of Open Access Journals (Sweden)

    Emad A. Elshehy

    2014-10-01

    Full Text Available We fabricated silica nanotubes with hexagonally ordered mesopores (6 nm inside a membrane disc with a uniform channel neck size of 200 nm and a longitudinal thickness of 60 μm to design an optical sensor membrane (OSM for the screening and sensing of extremely toxic Hg(II ions. The optical detection and quantitative recognition of Hg(II ions in water were conducted even at trace concentrations without the need for sophisticated instruments. The OSM design was based on the physical interaction of a responsive organic probe with silica pore surfaces followed by strong and selective binding Hg(II–probe interactions under specific sensing conditions, particularly at pH 5. Ultra-trace concentrations of Hg(II ions were easily detected with the naked eye using the OSM. The remarkable ion spectral response of Hg(II ion–OSM ensured the excellent quantification of the OSM for Hg(II ion sensing over a wide range of concentrations with a detection limit of 1.75 × 10−9 M. This result indicated that low concentrations of Hg(II ions can be detected with a high sensitivity. One of the key issues of OSM is the Hg(II ion-selective workability even in the presence of high doses of competitive matrices and species. The OSM design showed significant Hg(II ion-sensing capability despite the number of reuse/recycles using simple decomplexation. Given its high selectivity, fast response, and sensitivity, the OSM could be developed into a specific Hg(II ion-sensing kit in aqueous solutions.

  19. Ion permeation of AQP6 water channel protein. Single channel recordings after Hg2+ activation.

    Science.gov (United States)

    Hazama, Akihiro; Kozono, David; Guggino, William B; Agre, Peter; Yasui, Masato

    2002-08-01

    Aquaporin-6 (AQP6) has recently been identified as an intracellular vesicle water channel with anion permeability that is activated by low pH or HgCl2. Here we present direct evidence of AQP6 channel gating using patch clamp techniques. Cell-attached patch recordings of AQP6 expressed in Xenopus laevis oocytes indicated that AQP6 is a gated channel with intermediate conductance (49 picosiemens in 100 mm NaCl) induced by 10 microm HgCl2. Current-voltage relationships were linear, and open probability was fairly constant at any given voltage, indicating that Hg2+-induced AQP6 conductance is voltage-independent. The excised outside-out patch recording revealed rapid activation of AQP6 channels immediately after application of 10 microm HgCl2. Reduction of both Na+ and Cl- concentrations from 100 to 30 mm did not shift the reversal potential of the Hg2+-induced AQP6 current, suggesting that Na+ is as permeable as Cl-. The Na+ permeability of Hg2+-induced AQP6 current was further demonstrated by 22Na+ influx measurements. Site-directed mutagenesis identified Cys-155 and Cys-190 residues as the sites of Hg2+ activation both for water permeability and ion conductance. The Hill coefficient from the concentration-response curve for Hg2+-induced conductance was 1.1 +/- 0.3. These data provide the first evidence of AQP6 channel gating at a single-channel level and suggest that each monomer contains the pore region for ions based on the number of Hg2+-binding sites and the kinetics of Hg2+-activation of the channel. PMID:12034750

  20. Trace element analysis of three tissues from Eurasian otters (Lutra lutra) in South Korea.

    Science.gov (United States)

    Kang, Sukmo; Kang, Jung-Hoon; Kim, Soohee; Lee, Seung Heon; Lee, Seungwoo; Yu, Hee Jeong; Oh, Su-Jun; Park, Jung-Duck; Nam, Ki-Hoan; Han, Sung Yong; Lim, Jong-Deock; Ryu, Doug-Young

    2015-07-01

    Eurasian otters (Lutra lutra) are endangered worldwide, but the specific cause of their decline has not been determined. This study analyzed the concentrations of potentially toxic trace elements, including As, Cd, Pb, Hg, Se, Cu, Mn, and Zn, in the liver, kidney, and lung tissues of Eurasian otters in South Korea. There were high individual variations in the tissue concentrations of all the elements analyzed. The kidneys had the highest concentrations of Cd and Se among the three tissue groups, and the livers had the highest concentrations of Cu, Mn, Zn, and Hg. The Pb and As concentrations in the livers were not significantly different from those in the kidneys, and the lungs had the lowest concentrations of all the elements analyzed. The age-related bioaccumulation of Cd and Hg was evident in the three tissue groups, and of Se in the kidneys. The Pb concentration was higher in the livers of juveniles compared with those of adults and the Zn concentration was higher in the lungs of juveniles. There were no apparent gender differences in the concentrations of the elements analyzed among the tissue groups. The Se concentration correlated with the Hg concentration in the livers and kidneys, and with the Cd concentration in the kidneys. The Hg and Cd levels correlated in the three tissue groups. The Cu and Zn levels also correlated in the livers and kidneys. In general, the element concentrations were within the ranges reported by previous studies of this species from European countries, except for Cd and Hg, the levels of which were mostly lower than those reported previously. These findings may provide baseline information to facilitate the conservation of the Eurasian otter. To the best of our knowledge, this is the first available study of trace element concentrations in the tissues of Eurasian otters from South Korea or Asian countries. PMID:25762104

  1. Synthesis of N,N,N-4,4"-Di-(4-methylphenyl)-2,2':6',2"-terpyridine-N,N,N-tris(isothiocyanato) Ruthenium(Ⅱ) and Application to Colorimetric Hg2+ Sensor

    Institute of Scientific and Technical Information of China (English)

    LI Xiang-Hong; LIU Zhi-Qiang; LI Fu-You; DUAN Xin-Fang; HUANG Chun-Hui

    2007-01-01

    A terpyridine derivative DPTP [di-(4-methylphenyl)-2,2':6',2"-terpyridine] was conveniently synthesized from 2-bromopyridine via halogen-dance reaction, Kharash coupling and Stille coupling reaction. Then its corresponding ruthenium complex Ru-DPTP [N,N,N-4,4"-di-(4-methylphenyl)-2,2':6',2"-terpyridine-N,N,N-tris(iso-thiocyanato)-ruthenium(Ⅱ) ammonium] was obtained and fully characterized by IR, UV-Vis, ESI MS and elemental analysis. The MLCT absorption band of Ru-DPTP was blue-shifted from 570 to 500 nm upon addition of Hg2+. Among a series of surveyed metal ions, the complex showed a unique recognition to Hg2+, indicating that it can be used as a selective colorimetric sensor for Hg2+.

  2. Assessment of trace elements in honey produced on uranium mining reclaimed land

    International Nuclear Information System (INIS)

    The concentration of 24 elements in honey produced on uranium mining reclaimed land in Hobson, Texas was investigated by instrumental neutron activation analysis. These elements were: As, Ba, Br, Ce, Co, Cr, Cs, Fe, Hf, Hg, K, La, Na, Ni, Rb, Sb, Sc, Se, Sm, Sr, Th, U, Zn and Zr. The results obtained were compared to the concentration of the same elements in commercial honey and to the literature values for honey from different countries

  3. Atmospheric gaseous elemental mercury (GEM concentrations and mercury depositions at a high-altitude mountain peak in south China

    Directory of Open Access Journals (Sweden)

    X. W. Fu

    2010-03-01

    Full Text Available China is regarded as the largest contributor of mercury (Hg to the global atmospheric Hg budget. However, concentration levels and depositions of atmospheric Hg in China are poorly known. Continuous measurements of atmospheric gaseous elemental mercury (GEM were carried out from May 2008 to May 2009 at the summit of Mt. Leigong in south China. Simultaneously, deposition fluxes of THg and MeHg in precipitation, throughfall and litterfall were also studied. Atmospheric GEM concentrations averaged 2.80±1.51 ng m−3, which was highly elevated compared to global background values but much lower than semi-rural and industrial/urban areas in China. Sources identification indicates that both regional industrial emissions and long range transport of Hg from central, south and southwest China were corresponded to the elevated GEM level. Seasonal and diurnal variations of GEM were observed, which reflected variations in source intensity, deposition processes and meteorological factors. Precipitation and throughfall deposition fluxes of THg and MeHg in Mt. Leigong were comparable or lower compared to those reported in Europe and North America, whereas litterfall deposition fluxes of THg and MeHg were higher compared to Europe and North America. This highlights the importance of vegetation to Hg atmospheric cycling. In th remote forest ecosystem of China, deposition of GEM via uptake of foliage followed by litterfall was very important for the depletion of atmospheric Hg. Elevated GEM level in ambient air may accelerate the foliar uptake of Hg through air which may partly explain the elevated litterfall deposition fluxes of Hg observed in Mt. Leigong.

  4. Performance evaluation of non-thermal plasma injection for elemental mercury oxidation in a simulated flue gas

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • The use of non-thermal plasma injection approach to oxidize Hg0 in simulated flue gas at 110 °C was studied. • A high Hg0 oxidation efficiency was observed in the mixed flue gas that included O2, H2O, SO2, NO and HCl. • Chemical and physical processes (e.g., ozone, N2 metastable states and UV-light) contributed to Hg0 oxidation. • Mercury species mainly existed in the form of HgO(s) adhering to the suspended aerosols in the gas-phase. - Abstract: The use of non-thermal plasma (NTP) injection approach to oxidize elemental mercury (Hg0) in simulated flue gas at 110 °C was studied, where a surface discharge plasma reactor (SDPR) inserted in the simulated flue duct was used to generate and inject active species into the flue gas. Approximately 81% of the Hg0 was oxidized and 20.5 μg kJ−1 of energy yield was obtained at a rate of 3.9 J L−1. A maximal Hg0 oxidation efficiency was found with a change in the NTP injection air flow rate. A high Hg0 oxidation efficiency was observed in the mixed flue gas that included O2, H2O, SO2, NO and HCl. Chemical and physical processes (e.g., ozone, N2 metastable states and UV-light) were found to contribute to Hg0 oxidation, with ozone playing a dominant role. The deposited mercury species on the internal surface of the flue duct was analyzed using X-ray photoelectron spectroscopy (XPS) and electronic probe microanalysis (EPMA), and the deposit was identified as HgO. The mercury species is thought to primarily exist in the form of HgO(s) by adhering to the suspended aerosols in the gas-phase

  5. Novel Effective Catalyst for Elemental Mercury Removal from Coal-Fired Flue Gas and the Mechanism Investigation.

    Science.gov (United States)

    Chen, Wanmiao; Pei, Yang; Huang, Wenjun; Qu, Zan; Hu, Xiaofang; Yan, Naiqiang

    2016-03-01

    Mercury pollution from coal-fired power plants has drawn attention worldwide. To achieve efficient catalytic oxidation of Hg(0) at both high and low temperatures, we prepared and tested novel IrO2 modified Ce-Zr solid solution catalysts under various conditions. It was found that the IrO2/Ce0.6Zr0.4O2 catalyst, which was prepared using the polyvinylpyrrolidone-assisted sol-gel method, displayed significantly higher catalytic activity for Hg(0) oxidation. The mechanism of Hg(0) removal over IrO2/Ce0.6Zr0.4O2 was studied using various methods, and the Hg(0) oxidation reaction was found to follow two possible pathways. For the new chemisorption-regeneration mechanism proposed in this study, the adsorbed Hg(0) was first oxidized with surface chemisorbed oxygen species to form HgO; the HgO could desorb from the surface of catalysts by itself or react with adsorbed HCl to be release in the form of gaseous HgCl2. O2 is indispensable for the chemisorption process, and the doping of IrO2 could facilitate the chemisorption process. In addition, the Deacon reaction mechanism was also feasible for Hg(0) oxidation: this reaction would involve first oxidizing the adsorbed HCl to active Cl species, after which the Hg(0) could react with Cl to form HgCl2. Additionally, doping IrO2 could significantly improve the Cl yield process. In summary, the novel IrO2 modified catalyst displayed excellent catalytic activity for elemental mercury oxidation, and the proposed reaction mechanisms were determined reasonably. PMID:26815147

  6. Organ-specific accumulation, transportation, and elimination of methylmercury and inorganic mercury in a low Hg accumulating fish.

    Science.gov (United States)

    Peng, Xiaoyan; Liu, Fengjie; Wang, Wen-Xiong

    2016-08-01

    Low mercury (Hg) concentrations down to several nanograms Hg per gram of wet tissue are documented in certain fish species such as herbivorous fish, and the underlying mechanisms remain speculative. In the present study, bioaccumulation and depuration patterns of inorganic Hg(II) and methylmercury (MeHg) in a herbivorous rabbitfish Siganus canaliculatus were investigated at organ and subcellular levels following waterborne or dietary exposures. The results showed that the efflux rate constants of Hg(II) and MeHg were 0.104 d(-1) and 0.024 d(-1) , respectively, and are probably the highest rate constants recorded in fish thus far. The dietary MeHg assimilation efficiency (68%) was much lower than those in other fish species (∼90%). The predominant distribution of MeHg in fish muscle was attributable to negligible elimination of MeHg from muscle (< 0) and efficient elimination of MeHg from gills (0.12 d(-1) ), liver (0.17 d(-1) ), and intestine (0.20 d(-1) ), as well as efficient transportation of MeHg from other organs into muscle. In contrast, Hg(II) was much more slowly distributed into muscle but was efficiently eliminated by the intestine (0.13 d(-1) ). Subcellular distribution indicated that some specific membrane proteins in muscle were the primary binding pools for MeHg, and both metallothionein-like proteins and Hg-rich granules were the important components in eliminating both MeHg and Hg(II). Overall, the present study's results suggest that the low tissue Hg concentration in the rabbitfish was partly explained by its unique biokinetics. Environ Toxicol Chem 2016;35:2074-2083. © 2016 SETAC. PMID:26756981

  7. Trace elements in striped dolphins (Stenella coeruleoalba) from the Eastern Mediterranean: A 10-years perspective.

    Science.gov (United States)

    Shoham-Frider, Efrat; Goffman, Oz; Harlavan, Yehudit; Kress, Nurit; Morick, Danny; Roditi-Elasar, Mia; Shefer, Edna; Kerem, Dan

    2016-08-15

    Concentrations of Hg, Se, Cd, Cu, Zn, Fe, Mn and As, in kidney, liver, muscle and blubber from 7 specimens of Stenella coeruleoalba, stranded along the Israeli Mediterranean coast (IMC) from 2006 to 2011 (2011-series) were determined and compared to previous data on S. coeruleoalba from the IMC (2001-series). No differences were observed in essential and toxic elements concentrations, between the two series, except for hepatic Mn which was higher in the latter. Hg/Se molar ratios in blubber, kidney and liver increased linearly with log Hg concentrations, while muscle was more heterogenic in this respect. Means (±SD) of hepatic Hg concentrations (134±89 and 181±200mgkg(-1), from the 2011 and 2001 series, respectively) were similar to that found in 2007-2009 specimens from Spain, possibly reflecting the relatively high natural background levels of mercury in the Mediterranean Sea. PMID:27210566

  8. Assessing element-specific patterns of bioaccumulation across New England lakes

    International Nuclear Information System (INIS)

    Little is known about differences among trace elements in patterns of bioaccumulation in freshwater food webs. Our goal was to identify patterns in bioaccumulation of different elements that are large and consistent enough to discern despite variation across lakes. We measured methylmercury (MeHg) and trace element (As, Cd, Hg, Pb, and Zn) concentrations in food web components of seven New England lakes on 3–5 dates per lake, and contrasted patterns of bioaccumulation across lakes, metals and seasons. In each lake, trace element concentrations were compared across trophic levels, including three size fractions of zooplankton, planktivorous fish, and piscivorous fish. The trophic position of each food web component was estimated from N isotope analysis. Trace element concentrations varied widely among taxa, lakes and sampling dates. Yet, we identified four consistent patterns of bioaccumulation that were consistent across lakes: (1) MeHg concentration increased (i.e., was biomagnified) and Pb concentration decreased (i.e., was biodiminished) with increased trophic position. (2) Zinc concentration (as with MeHg) was higher in fish than in zooplankton, but overall variation in Zn concentration (unlike MeHg) was low. (3) Arsenic and Cd concentrations (as with Pb) were lower in fish than in zooplankton, but (unlike Pb) were not significantly correlated with trophic position within zooplankton or fish groups. (4) Average summer concentrations of As, Pb, Hg, and MeHg in zooplankton significantly predicted their concentrations in either planktivorous or piscivorous fish. Our secondary goal was to review sampling approaches in forty-five published studies to determine the extent to which current sampling programs facilitate cross-lake and cross-study comparisons of bioaccumulation. We found that studies include different components of the food web and sample too infrequently to enable strong cross-lake and cross-study comparisons. We discuss sampling strategies that would

  9. Determination of toxic and essential element concentrations in foodstuffs from local market

    International Nuclear Information System (INIS)

    Determination of toxic and essential elements concentrations in foodstuffs from local market in Jakarta. Concentration of toxic essential elements, such as, As, Hg, Cr, Pb, Cu, and Zn, in rice, corn bean, small green peas, wheat, vegetables, fruits, tea and coffee, have been determined. As, Hg, Sb, Cr, Se, and Zn, were determined using neutron activation analysis, after being irradiated at TRIGA-MARK II reactor, while Pb and Cu were determined using atomic absorption spectrophotometer. The results obtained were lower than the maximum permissible concentration allowed. (author). 8 refs

  10. Assessing element-specific patterns of bioaccumulation across New England lakes

    Energy Technology Data Exchange (ETDEWEB)

    Ward, Darren M.; Mayes, Brandon; Sturup, Stefan; Folt, Carol L.; Chen, Celia Y., E-mail: celia.chen@dartmouth.edu

    2012-04-01

    Little is known about differences among trace elements in patterns of bioaccumulation in freshwater food webs. Our goal was to identify patterns in bioaccumulation of different elements that are large and consistent enough to discern despite variation across lakes. We measured methylmercury (MeHg) and trace element (As, Cd, Hg, Pb, and Zn) concentrations in food web components of seven New England lakes on 3-5 dates per lake, and contrasted patterns of bioaccumulation across lakes, metals and seasons. In each lake, trace element concentrations were compared across trophic levels, including three size fractions of zooplankton, planktivorous fish, and piscivorous fish. The trophic position of each food web component was estimated from N isotope analysis. Trace element concentrations varied widely among taxa, lakes and sampling dates. Yet, we identified four consistent patterns of bioaccumulation that were consistent across lakes: (1) MeHg concentration increased (i.e., was biomagnified) and Pb concentration decreased (i.e., was biodiminished) with increased trophic position. (2) Zinc concentration (as with MeHg) was higher in fish than in zooplankton, but overall variation in Zn concentration (unlike MeHg) was low. (3) Arsenic and Cd concentrations (as with Pb) were lower in fish than in zooplankton, but (unlike Pb) were not significantly correlated with trophic position within zooplankton or fish groups. (4) Average summer concentrations of As, Pb, Hg, and MeHg in zooplankton significantly predicted their concentrations in either planktivorous or piscivorous fish. Our secondary goal was to review sampling approaches in forty-five published studies to determine the extent to which current sampling programs facilitate cross-lake and cross-study comparisons of bioaccumulation. We found that studies include different components of the food web and sample too infrequently to enable strong cross-lake and cross-study comparisons. We discuss sampling strategies that would

  11. Electric dipole moments of superheavy elements: A case study on copernicium

    Science.gov (United States)

    RadžiÅ«tÄ--, Laima; Gaigalas, Gediminas; Jönsson, Per; Bieroń, Jacek

    2016-06-01

    The multiconfiguration Dirac-Hartree-Fock method was employed to calculate the atomic electric dipole moments (EDMs) of the superheavy element copernicium (Cn, Z =112 ). The EDM enhancement factors of Cn, calculated here, are about one order of magnitude larger than those of Hg. The exponential dependence of the enhancement factors on the atomic number Z along group 12 of the periodic table was derived from the EDMs of the entire homologous series, Zn, Cd, Hg, Cn, and Uhb. These results show that superheavy elements with sufficiently long half-lives are potential candidates for EDM searches.

  12. Toxic and essential elements changed in black-legged kittiwakes (Rissa tridactyla) during their stay in an Arctic breeding area

    Energy Technology Data Exchange (ETDEWEB)

    Øverjordet, Ida Beathe, E-mail: ida.beathe.overjordet@sintef.no [Norwegian University of Science and Technology (NTNU), Department of Biology, N-7491 Trondheim (Norway); Kongsrud, Magnus Brunvoll [Norwegian University of Science and Technology (NTNU), Department of Biology, N-7491 Trondheim (Norway); Gabrielsen, Geir Wing [Norwegian Polar Institute, N-9296 Tromsø (Norway); Berg, Torunn [NTNU, Department of Chemistry, N-7491 Trondheim (Norway); Ruus, Anders [Norwegian Institute for Water Research (NIVA), N-0349 Oslo (Norway); Evenset, Anita [Akvaplan-niva, Fram Centre, N-9296 Tromsø (Norway); Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway (Norway); Borgå, Katrine [Norwegian Institute for Water Research (NIVA), N-0349 Oslo (Norway); Department of Biosciences, University of Oslo (Norway); Christensen, Guttorm [Akvaplan-niva, Fram Centre, N-9296 Tromsø (Norway); Jenssen, Bjørn Munro [Norwegian University of Science and Technology (NTNU), Department of Biology, N-7491 Trondheim (Norway)

    2015-01-01

    Seasonal fluctuations in mercury (Hg), cadmium (Cd), zinc (Zn), copper (Cu) and selenium (Se) concentrations were studied in black-legged kittiwakes (Rissa tridactyla) from Kongsfjorden, Svalbard (79°57′N, 12°12′E). Element concentrations were determined in muscle and liver tissue in kittiwakes collected in May, July and October 2007. Stable isotopes of carbon (δ{sup 13}C) and nitrogen (δ{sup 15}N) were analysed in muscle tissue to calculate trophic position (TP) and examine the possible influence of carbon source on element accumulation. Metallothionein (MT) concentrations in liver, as well as Hg and Cd concentration in size-fractionated liver supernatant were determined to evaluate the association between elements and MT. Mercury concentrations declined from May through July to October in both tissues, while concentrations of Cd were similar in May and July and lower in October. A decline in TP between May and July, indicating a shift from fish-based diet towards an invertebrate-based diet explains the declining Hg concentration. The low Hg and Cd concentrations in October may be a result of an increased elimination, probably related to moulting. Selenium decreased in the same manner as Hg in liver and muscle, possibly related to the formation of Se–Hg complexes. Zinc and Cu did not fluctuate in muscle tissue, whereas hepatic Zn concentrations where highest in May. Hepatic Zn concentrations were higher in females compared to males in May, possibly related to egg production. Hepatic MT concentrations were lower in October compared to July, following the same trend as Hg and Cd. Cadmium was predominantly bound to the MT fraction of proteins in liver tissue, whereas Hg was associated with the larger proteins, indicating that MT was not sequestering Hg in the kittiwakes. - Highlights: • Seasonality of Cd and Hg is closely related to seasonal dietary changes. • Migration patterns influence the accumulation of Hg and Cd. • The seasonality of Se and Hg

  13. Neutron cross sections for 93Nb(n, n')93mNb and 199Hg(n, n')199mHg reactions compiled in JENDL dosimetry file

    International Nuclear Information System (INIS)

    Evaluation procedure of neutron cross sections and covariance matrixes for 93Nb(n, n')93mNb and 199Hg(n, n')199mHg reactions is described in detail. The C/E value of 235U fission spectrum averaged cross section is 0.99 for 93Nb(n, n')93mNb reaction and 0.86 for 199Hg(n, n')199mHg reaction, respectively. (author)

  14. Heavy elements (I). From transuranium elements to superheavy elements

    International Nuclear Information System (INIS)

    History of the synthesis and discovery of heavy elements starting from 93 is reviewed. This article describes the story of thrilling competition for the discovery of new elements with increasing difficulties as the atomic number increases, beginning the 93 element, neptunium. Particularly, competition between USA and USSR has lasted from 102 to 106 element and was unsettled until a new aspect was developed in relation with the superheavy elements theoretically predicted. Here, the search of naturally occurring superheavy elements is briefly explained as an introduction to the present and future perspectives of the research on the superheavy elements which is appearing in the succeeding article. (author)

  15. Experimental analysis of the simultaneous uptake of the heavy metals Cd, Hg, Pb, Cu, Zn, Se in the sporophore of mushrooms. Versuche ueber die simultane Aufnahme der Schwermetalle Cd, Hg, Pb, Cu, Zn und Se in Pilzfruchtkoerper

    Energy Technology Data Exchange (ETDEWEB)

    Suehs, K.

    With mushrooms of the species Agaricus bisporus and Boletus badius the simultaneous uptake of the heavy metals Cd, Hg, Pb, Cu, Zn, and Se from soil to the sporophore was studied. To avoid misleadingly overrated enrichmentfactors when comparing the heavy metal contents of dried mushrooms and soils, a so-called transfer factor TF[sub v] which is related to the volume is put to discussion here, this factor takes account of the relatively small amount of dry matter in mushrooms and of the different composition (that means specific weight) of the soils in question. With help of these transfer factors the conclusion is derived, that essential elements show a better enrichment behaviour than biologically superfluous heavy metals, at least this is true with the insignificantly contaminated soils we investigated. With Cd as an example of a ''superfluous'' element it is shown that there is a strict proportionality of Cd concentrations in the mushrooms and the corresponding soils, thus producing a constant transfer factor. Apart from this the uptake of copper into the mushrooms is promoted (growth of the transfer factor) by a larger Cd supply, whereas the other elements under investigation (even the classical antagonist Zn) are not significantly affected. Furthermore there is evidence that with increasing heavy metal concentration (Cd) first the fructification of the thallus is supported and moreover, that increasing age of this primary fungus corresponds with an increase of heavy metals in the mushrooms. (orig.)

  16. The vertical photoconductor: A novel device structure suitable for HgCdTe two-dimensional infrared focal plane arrays

    Science.gov (United States)

    Siliquini, J. F.; Faraone, L.

    1997-06-01

    A novel photoconductive device structure is proposed and described that has been designed specifically as a sensing element for high density two-dimensional infrared focal plane array (IRFPA) applications. Although the design concept can be applied to a variety of epitaxially grown HgCdTe material, optimum performance can be achieved using n-type HgCdTe semiconductor material consisting of epitaxially grown heterostructure layers in which a two-dimensional mosaic of vertical design photoconductors are fabricated. The heterostructure layers provide high performance devices at greatly reduced power dissipation levels, while the vertical design allows for the high density integration of photoconductors in a two-dimensional array geometry with high fill factor. The salient feature of the proposed device structure is that the bias field is applied in the vertical direction such that it is parallel to the impinging infrared radiation. A comprehensive one-dimensional model is presented for the vertical design photoconductor, which is subsequently used to determine the optimum design parameters in order to achieve maximum responsivity at the lowest possible power dissipation level. It is found that the proposed device structure has the potential to be used in the fabrication of long wavelength IRFPAs approaching 10 6 pixels using 25 × 25 μm 2 detector elements. Furthermore, this is achieved with individual device detectivities that are background limited and for a total array power dissipation of less than 0.1 W using a pulsed biasing scheme. Performance issues such as response uniformity, pixel yield, fill factor, crosstalk, power dissipation, detector impedance, array architecture, and maximum array size are discussed in relation to the suitability of the proposed vertical photoconductor structure for use in IRFPA modules. When considering IRFPA operability, it is found that in many cases the proposed technology has the potential to deliver significant advantages, such

  17. Differential bioaccumulation of potentially toxic elements in benthic and pelagic food chains in Lake Baikal.

    Science.gov (United States)

    Ciesielski, Tomasz M; Pastukhov, Mikhail V; Leeves, Sara A; Farkas, Julia; Lierhagen, Syverin; Poletaeva, Vera I; Jenssen, Bjørn M

    2016-08-01

    Lake Baikal is located in eastern Siberia in the center of a vast mountain region. Even though the lake is regarded as a unique and pristine ecosystem, there are existing sources of anthropogenic pollution to the lake. In this study, the concentrations of the potentially toxic trace elements As, Cd, Pb, Hg, and Se were analyzed in water, plankton, invertebrates, and fish from riverine and pelagic influenced sites in Lake Baikal. Concentrations of Cd, Hg, Pb and Se in Lake Baikal water and biota were low, while concentrations of As were similar or slightly higher compared to in other freshwater ecosystems. The bioaccumulation potential of the trace elements in both the pelagic and the benthic ecosystems differed between the Selenga Shallows (riverine influence) and the Listvenichnyĭ Bay (pelagic influence). Despite the one order of magnitude higher water concentrations of Pb in the Selenga Shallows, Pb concentrations were significantly higher in both pelagic and benthic fish from the Listvenichnyĭ Bay. A similar trend was observed for Cd, Hg, and Se. The identified enhanced bioavailability of contaminants in the pelagic influenced Listvenichnyĭ Bay may be attributed to a lower abundance of natural ligands for contaminant complexation. Hg was found to biomagnify in both benthic and pelagic Baikal food chains, while As, Cd, and Pb were biodiluted. At both locations, Hg concentrations were around seven times higher in benthic than in pelagic fish, while pelagic fish had two times higher As concentrations compared to benthic fish. The calculated Se/Hg molar ratios revealed that, even though Lake Baikal is located in a Se-deficient region, Se is still present in excess over Hg and therefore the probability of Hg induced toxicity in the endemic fish species of Lake Baikal is assumed to be low. PMID:27130338

  18. Multi-element determination in earthworms with instrumental neutron activation analysis and inductively coupled plasma mass spectrometry. A comparison

    International Nuclear Information System (INIS)

    Earthworms were collected from agricultural fields in Admont, Graz, Piber and Gumpenstein, Austria. Six earthworm samples were investigated with INAA and with ICP-MS in parallel for the element concentrations of As, Ba, Cd, Co, Cr, Cu, Fe, Hg, Pb, Rb, Sb, Se and Zn. With both techniques 14 elements were analysed in a wide concentration range (ng/g to mg/g). GF-AAS and HG-AAS were used for verification of some element concentrations. A comparison of analytical results between INAA and ICP-MS was discussed. In general, good agreement between ICP-MS and INAA was obtained, the relative difference values of most of the elements are within ± 20% range, however, a methodical error for the determination of Hg by ICP-MS was found. (author)

  19. Ecological variables influencing trace element concentrations in bottlenose dolphins (Tursiops truncatus, Montagu 1821) stranded in continental Portugal.

    Science.gov (United States)

    Monteiro, Sílvia S; Torres, Jordi; Ferreira, Marisa; Marçalo, Ana; Nicolau, Lídia; Vingada, José V; Eira, Catarina

    2016-02-15

    Both the conservation status of bottlenose dolphins (Tursiops truncatus) (Habitats Directive 92/43/CEE, Annex II) and the Marine Strategy Framework Directive demand for data on their ecology and anthropogenic threats. To evaluate the bottlenose dolphin's toxicological status in continental Portugal, several trace elements (As, Cd, Cu, Hg, Mn, Ni, Pb, Se, Zn) were determined in 25 stranded individuals. The potential effect of sex, body length and stranding location on trace element concentrations was analysed. In the present study, bottlenose dolphins presented high mercury levels, only exceeded by animals from the Mediterranean and Adriatic seas. Only essential elements were influenced by dolphin sex, whereas Cd, Hg and Pb bioaccumulated in larger dolphins, and hepatic Hg and Cd concentrations were higher in the northwest coast of continental Portugal. The location effect may relate to variations in bottlenose diet and trace element availability, according to the proximity to anthropogenic sources in the Atlantic Iberian coast. PMID:26706756

  20. In Situ Behavioral Response of Common Loons Associated with Elevated Mercury (Hg Exposure

    Directory of Open Access Journals (Sweden)

    Philip D. Taylor

    1998-12-01

    Full Text Available Common Loons (Gavia immer in Nova Scotia, Canada have the highest blood mercury (Hg concentrations of any loon population in North America. Previous studies have shown that exposure to varying levels of Hg in prey is associated with changes in pre-nesting adult behavior. We report here the first association of sublethal blood Hg contamination with changes in behavior of Common Loon young. As Hg levels in their blood rise, the amount of time that chicks spend brooding (by back-riding decreases (P = 0.004 and time spent preening increases (P = 0.003. The sum increase in energy expenditure is not being compensated for with expected increases in feeding rates or begging. We suggest that such altered time-activity budgets may disrupt the energetic balance of young. Our results show that variation in time spent back-riding is associated with changes in fledging rates. Adult behavior did not significantly vary with Hg, but results are suggestive that an association may exist. We also show that monitoring the time-activity budgets of very young chicks can serve to indicate the effects Hg concentrations in their blood. We confirm the hypothesis that loons and other upper trophic level predators could be at risk from elevated levels of bioavailable Hg. This may help to explain the chronically low productivity of such contaminated sites as Kejimkujik and allow for more focused management initiatives.