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Sample records for iodine adsorption dissociation

  1. Dissociation of molecular iodine in RF discharge for oxygen-iodine laser

    Czech Academy of Sciences Publication Activity Database

    Jirásek, Vít; Schmiedberger, Josef; Čenský, Miroslav; Kodymová, Jarmila

    2012-01-01

    Roč. 66, č. 4 (2012), 1-6 ISSN 1434-6060 R&D Projects: GA ČR GA202/09/0310 Grant - others:European Office for Aerospace R&D(XE) FA8655-09-1-3092 Institutional research plan: CEZ:AV0Z10100523 Keywords : molecular iodine * RF discharge * dissociation * oxygen-iodine laser * COIL Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.513, year: 2012

  2. Combined DFT and XPS investigation of iodine anions adsorption on the sulfur terminated (001) chalcopyrite surface

    Energy Technology Data Exchange (ETDEWEB)

    Li, Kui, E-mail: likui9606@stu.xjtu.edu.cn [School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049 (China); Zhao, Yaolin, E-mail: zhaoyaolin@mail.xjtu.edu.cn [School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049 (China); Zhang, Peng, E-mail: zp32@qq.com [Sino Shaanxi Nuclear Industry Group, Xi’an 710100 (China); He, Chaohui, E-mail: hechaohui@mail.xjtu.edu.cn [School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049 (China); Deng, Jia, E-mail: djkokocase@stu.xjtu.edu.cn [School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049 (China); Ding, Shujiang, E-mail: dingsj@mail.xjtu.edu.cn [Department of Applied Chemistry, School of Science, Xi’an Jiaotong University, Xi’an 710049 (China); Shi, Weiqun, E-mail: shiwq@ihep.ac.cn [Key Laboratory of Nuclear Radiation and Nuclear Energy Technology and Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

    2016-12-30

    Highlights: • Metal surface sites of (001)-S surface of chalcopyrite show significant chemical affinity to iodide and iodate. • The energetically favorable active site is copper for iodide adsorption and iron for iodate adsorption, respectively. • Iodate undergoes a dissociative adsorption on the copper site of chalcopyrite surface. - Abstract: The adsorption of iodine anions (iodide and iodate) on the sulfur terminated (001) chalcopyrite surface has been systematically investigated combining first-principles calculations based on density functional theory (DFT) with X-ray photoelectron spectroscopy (XPS) measurements. Based on the total energy calculations and geometric optimization, the thermodynamically preferred site was copper atom for iodide adsorption and iron atom for iodate adsorption, respectively. In the case of Cu site mode, the iodate underwent a dissociative adsorption, where one I−O bond of iodate ion was broken and the dissociative oxygen atom adsorbed on the adjacent sulphur site. Projected density of states (PDOS) analysis further clarified the interaction mechanism between active sites of chalcopyrite surface and adsorbates. In addition, full-range XPS spectra qualitatively revealed the presence of iodine on chalcopyrite surface. High resolution XPS spectra of the I 3d peaks after adsorption verified the chemical environment of iodine. The binding energies of 618.8 eV and 623.5 eV for I 3d{sub 5/2} peaks unveiled that the adsorption of iodide and iodate ions on copper-iron sulfide minerals was the result of formation of low solubility metal iodides precipitate. Also two I 3d peaks with low intensity around 618 eV and 630 eV might be related to the inorganic reduction of iodate to iodide by reducing S{sup 2−} ion of chalcopyrite.

  3. Adsorption of iodine and cesium onto some cement materials

    Energy Technology Data Exchange (ETDEWEB)

    Mine, Tatsuya [Mitsui Shipbuilding and Engineering Co. Ltd., Tokyo (Japan); Mihara, Morihiro; Ito, Masaru [Power Reactor and Nuclear Fuel Development Corp., Tokai, Ibaraki (Japan). Tokai Works; Kato, Hiroshige [IDC, Tokai, Ibaraki (Japan)

    1997-06-01

    Cement materials, being expected to be used in structural materials in underground disposals of radioactive wastes, may adsorb nuclides resulting in retardation of their migration in environment. In this report adsorption behaviors of cement pastes toward iodine (as anion) and cesium (as cation) were studied. Adsorption of iodine was remarkable for OPC and MHP pastes that are known to have high molar ratio CaO/SiO{sub 2}, partition coefficient being 100 ml/g for initial tracer concentration of 10{sup -5} mol/l. Partition coefficient for cesium for PFA paste was found to be 5 ml/g on average. (S. Ohno)

  4. Adsorption of iodine and cesium onto some cement materials

    International Nuclear Information System (INIS)

    Mine, Tatsuya; Mihara, Morihiro; Ito, Masaru

    1997-06-01

    Cement materials, being expected to be used in structural materials in underground disposals of radioactive wastes, may adsorb nuclides resulting in retardation of their migration in environment. In this report adsorption behaviors of cement pastes toward iodine (as anion) and cesium (as cation) were studied. Adsorption of iodine was remarkable for OPC and MHP pastes that are known to have high molar ratio CaO/SiO 2 , partition coefficient being 100 ml/g for initial tracer concentration of 10 -5 mol/l. Partition coefficient for cesium for PFA paste was found to be 5 ml/g on average. (S. Ohno)

  5. Ultrahigh iodine adsorption in porous organic frameworks

    KAUST Repository

    Pei, Cuiying

    2014-01-01

    We present two porous organic frameworks (POFs), PAF-1 and JUC-Z2, with ultrahigh iodine capture capacity. The iodine vapor uptake of PAF-1 and JUC-Z2 were 1.86 g g-1 and 1.44 g g-1 respectively at 298 K per 40 Pa, which is extremely high for such low pressure sorption conditions. In addition, PAF-1 and JUC-Z2 could adsorb iodine over water with the selectivity of 5.1 and 6.5 respectively. The isosteric enthalpy at zero surface coverage, calculated by a virial equation with the iodine vapor sorption isotherms at 298 K and 313 K of JUC-Z2, reached -51.1 kJ mol-1, which was much higher than the coverage of PAF-1 (-14.9 kJ mol-1). Raman measurement confirmed the polyiodide to be I5 - in POFs. Furthermore, solvents with different polarities, such as n-hexane, chloroform, and methanol, were chosen to conduct iodine binding measurements on PAF-1 and JUC-Z2. The formation constant Kf for POFs in n-hexane, chloroform and methanol drastically decreased with the increase in polarity, thus illustrating the important role of solvents in iodine binding. © the Partner Organisations 2014.

  6. Study on adsorption performance of coal based activated carbon to radioactive iodine and stable iodine

    International Nuclear Information System (INIS)

    Zhou, Junbo; Hao, Shan; Gao, Liping; Zhang, Youchen

    2014-01-01

    Highlights: • The impregnated coal-based activated carbons as adsorbent for removing methyl iodide. • The coal-based activated carbons to remove stable iodine. • Iodine residues are under 0.5 μg/ml after adsorption treatment. • The decontamination factor is much higher than 1000. - Abstract: Nuclear power plant, nuclear reactors and nuclear powered ship exhaust contains a large amount of gaseous radioactive iodine, and can damage to the workplace and the surrounding environment. The quantitative test to remove methyl iodide and the qualitative test for removing stable iodine were investigated using the impregnated coal-based activated carbons and coal-based activated carbons as adsorbents. The research conducted in this work shows that iodine residues were under 0.5 μg/ml after adsorption treatment and the decontamination factor of the coal-based activated carbon for removing the stable iodine was more than 1000, which can achieve the purpose of removing harmful iodine, and satisfy the requirement of gaseous waste treatment of nuclear powered vessel and other nuclear plants

  7. Separation of iodine species by adsorption chromatography

    International Nuclear Information System (INIS)

    Machado, E.C.; Bellido Jr, A.V.

    2001-01-01

    Based on the different properties of iodide and iodate species in some sorption materials a new chromatographic method was developed to study the speciation of iodine in a mangrove system. Two sorption materials, alumina and silica, were investigated and several distribution coefficients for iodide and iodate were determined at different concentrations of NaOH, NaNO 3 and NaHCO 3 solutions. The best separation results were obtained percolating sea water samples, containing iodide species, through a glass column filled with alumina. The iodine passed through the column after washing the column with 0.1M sodium nitrate solution, and the iodate was eluted with a 0.5M sodium bicarbonate solution. (author)

  8. Heterolytic dissociative adsorption state of dihydrogen favored by interfacial defects

    Science.gov (United States)

    Song, Zhenjun; Hu, Hanshi; Xu, Hu; Li, Yong; Cheng, Peng; Zhao, Bin

    2018-03-01

    The atomic-scale insight into dihydrogen on MgO(001) surface deposited on molybdenum substrate with interfacial defects was investigated in detail by employing density functional methods Here we report novel dissociative adsorption behaviors of single hydrogen molecule on the usually inert oxide surfaces, with consideration of two types of dissociation schemes. The heterolytic dissociation state -Mg(H)-O(H)- of dihydrogen is impossible to obtain on neighboring O-Mg sites of perfect bulk MgO(001) terraces. Unusually, the hydrogen molecule can form heterolytic fragmentation states on metal supported MgO(001) films with very low activation barrier (0.398 eV), and the heterolytic dissociation state is much more favorable than homolytic dissociation state both energetically and kinetically in all cases. Electronic properties and bonding attribution of adsorbates and the oxide-metal hybrid structure are revealed by analyzing density of states, differential charge densities, orbital interaction and electron localization function. The characteristic changes to the property and activity of magnesia (001) can have potential application in catalytic reactions.

  9. Design of sample analysis device for iodine adsorption efficiency test in NPPs

    International Nuclear Information System (INIS)

    Ji Jinnan

    2015-01-01

    In nuclear power plants, iodine adsorption efficiency test is used to check the iodine adsorption efficiency of the iodine adsorber. The iodine adsorption efficiency can be calculated through the analysis of the test sample, and thus to determine if the performance of the adsorber meets the requirement on the equipment operation and emission. Considering the process of test and actual demand, in this paper, a special device for the analysis of this kind of test sample is designed. The application shows that the device is with convenient operation and high reliability and accurate calculation, and improves the experiment efficiency and reduces the experiment risk. (author)

  10. CO adsorption and dissociation on Pt(111) and Ni(111) surfaces

    DEFF Research Database (Denmark)

    Morikawa, Y.; Mortensen, Jens Jørgen; Hammer, Bjørk

    1997-01-01

    CO adsorption and dissociation processes have been studied using first-principles total energy and force calculations. The adsorption energies, atomic structures and vibrational modes of molecularly chemisorbed states are well reproduced in the present calculations. We have examined several...

  11. Study of adsorption properties of impregnated charcoal for airborne iodine and methyl iodide

    International Nuclear Information System (INIS)

    Qi-dong, L.; Sui-yuang, H.

    1985-01-01

    The adsorption characteristics of airborne radioiodine and methyl iodide on impregnated charcoal were investigated. The activated charcoal tested was made from home-made oil-palm shells, and KI and TEDA were used as impregnants. A new technique was used to plot the dynamic partial adsorption isotherm at challenge concentrations (concentration range of iodine: 1-20 ppm v/v). Some adsorption properties of the impregnated charcoal were estimated with the dynamic partial adsorption isotherm. The dependences of the adsorption capacity and penetration behavior for airborne iodine and methyl iodide on the ambient conditions (temperature, relative humidity, and superficial velocity) were studied

  12. Dissociation kinetics of iodine in oxygen-containing electrical discharge plasmas

    International Nuclear Information System (INIS)

    Zakharov, A.I.; Klopovskii, K.S.; Rakhimova, T.V.; Samorodov, V.A.

    1993-01-01

    Studies of the kinetics of gaseous media containing oxygen and iodine molecules have been stimulated to a substantial degree by the search for ways of improving iodine-oxygen lasers and by the need for information on loss processes for atmospheric ozone. Results are presented from an experimental study and numerical simulations of the kinetics of the dissociation of iodine in self-sustained volume discharges in high-pressure O 2 :Ar:I 2 mixtures. It is shown that the well-studied mechanism for dissociation based on excitation of iodine molecules in successive collisions with singlet oxygen and excited iodine atoms is supplanted by a substantially different mechanism involving the creation and loss of 10 radicals when the densities of atomic oxygen and ozone are high enough. It is also shown that iodine fractions as low as ∼10 -3 in the mixture lead to rapid loss of ozone molecules while less than 18% of the discharge energy is expended in the production of singlet oxygen

  13. Protein aggregation and degradation during iodine labeling and its consequences for protein adsorption to biomaterials

    DEFF Research Database (Denmark)

    Holmberg, Maria; Jensen, Karin Bagger Stibius; Ndoni, Sokol

    2007-01-01

    Protein adsorption on modified and unmodified polymer surfaces investigated through radiolabeling experiments showed a tendency for higher than expected albumin and immunoglobulin G (IgG) adsorption. Possible enhanced protein aggregation and degradation caused by the iodine labeling method used w...

  14. Studies of iodine adsorption and desorption on HTGR coolant circuit materials

    International Nuclear Information System (INIS)

    Osborne, M.F.; Compere, E.L.; de Nordwall, H.J.

    1976-04-01

    Safety studies of the HTGR system indicate that radioactive iodine, released from the fuel to the helium coolant, may pose a problem of concern if no attenuation of the amount of iodine released occurs in the coolant circuit. Since information on iodine behavior in this system was incomplete, iodine adsorption on HTGR materials was studied in vacuum as a function of iodine pressure and of adsorber temperature. Iodine coverages on Fe 3 O 4 and Cr 2 O 3 approached maxima of about 2 x 10 14 and 1 x 10 14 atoms/cm 2 , respectively, whereas the iodine coverage on graphite under similar conditions was found to be less by a factor of about 100. Iodine desorption from the same materials into vacuum or flowing helium was investigated, on a limited basis, as a function of iodine coverage, of adsorber temperature, and of dry vs wet helium. The rate of vacuum desorption from Fe 3 O 4 was related to the spectrum of energies of the adsorption sites. A small amount of water vapor in the helium enhanced desorption from iron powder but appeared to have less effect on desorption from the metal oxides

  15. Comparison of iodine, krypton, and xenon retention efficiencies for various silver loaded adsorption media

    International Nuclear Information System (INIS)

    Huchton, R.L.; Tkachyk, J.W.; Taylor, J.T.; Motes, B.G.

    1985-03-01

    A comparison was made among various silver impregnated adsorption media to determine their iodine, krypton, and xenon retention efficiencies. The program consisted of three components. First, laboratory measurements of the noble gas retention efficiencies of commercially available adsorption media were determined as a function of relative humidity, sample duration, test cartridge geometry, and ambient air purge. Second, a literature survey was performed to evaluate the iodine species retention efficiencies of the selected media. Third, data associated with a media previously proposed for an emergency response air sampler were incorporated to enlarge the data base. 41 refs., 6 figs., 14 tabs

  16. Iodine Adsorption by Ag-Aerogel under Prototypical Vessel Off-Gas Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Bruffey, Stephanie H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jubin, Robert Thomas [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-08-01

    U.S. regulations will require the removal of 129I from the off-gas streams of any used nuclear fuel (UNF) reprocessing plant prior to discharge of the off-gas to the environment. The required plant decontamination factor for iodine will vary based on fuel burnup, cooling time, and other factors but is very likely to be >1000 and could be as high as 8000. Multiple off-gas streams within a UNF reprocessing plant combine prior to environmental release, and each of these streams contains some amount of iodine. To achieve the decontamination factors (DFs) that are likely to be required by regulations, iodine removal from the vessel off-gas will be necessary. The vessel off-gas contains iodine at very dilute concentrations (ppb levels), and will also contain water vapor. Iodine species present are likely to include both elemental and organic iodides. There will also be solvent vapors and volatile radiolysis products. The United States has considered the use of silver-based sorbents for removal of iodine from UNF off-gas streams, but little is known about the behavior of those sorbents at very dilute iodine concentrations. The purpose of this study was to expose silver-functionalized silica aerogel (AgAerogel) to a prototypical vessel off-gas stream containing 40 ppb methyl iodide to obtain information about organic iodine capture by silver-sorbents at very low iodine concentrations. The design of this extended duration testing was such that information about the rate of adsorption, the penetration of the iodine species, and the overall system DF could be obtained. Results show that CH3I penetrates into a AgAerogel sorbent bed to a depth of 3.9 cm under prototypical vessel off-gas conditions. An iodine loading of 22 mg I/g AgAerogel was observed in the first 0.3 cm of the bed. Of the iodine delivered to the system, 48% could not be accounted for, and future efforts will investigate this concern. Direct calculation of the decontamination factor is not

  17. Water adsorption and dissociation on Ni(110): How is it different from its close packed counterparts?

    Energy Technology Data Exchange (ETDEWEB)

    Seenivasan, H.; Tiwari, Ashwani K., E-mail: ashwani@iiserkol.ac.in [Indian Institute of Science Education and Research Kolkata, Mohanpur 741252 (India)

    2014-05-07

    Water adsorption and dissociation on Ni(110) surface is studied in detail and compared with its close packed counterparts using density functional theory calculations. Water adsorption occurs on the top site as found on Ni(100) and Ni(111) but the adsorption is stronger on Ni(110). H and OH preferably adsorb on the short bridge sites (brgshort) opposed to hollow sites on (100) and (111) surfaces. Energy barriers for water molecule dissociation on Ni(110) as obtained from the transition state (TS) calculations were low compared to other Ni low indexed surfaces. TS geometries at different positions of the lattice coordinate, Q, were obtained to study the effect of surface temperature on dissociation of H{sub 2}O molecules. These calculations revealed that second layer atoms were also involved in the TS. Dissociation probabilities are obtained using a semi-classical approximation by sampling Q for a Boltzmann distribution at different temperatures. Results showed that the increasing surface temperature significantly increases the dissociation probabilities at lower energies and saturates near the barrier for dissociation. Although the contribution from both top and second layers is similar at low surface temperatures, motion of top layer atoms contribute more towards dissociation probability at higher surface temperatures. Dissociation probabilities obtained are more than one order of magnitude higher than that on Ni(100) and Ni(111) surfaces suggesting Ni(110) to be more reactive among the low indexed Ni surfaces.

  18. Adsorption of iodine from COIL waste gas on soaked coal-based activated carbon

    Science.gov (United States)

    Zhou, Junbo; Hao, Shan; Gao, Liping

    2014-04-01

    The chemical oxygen-iodine laser (COIL) has wide application prospects in military, industrial and medical treatment fields as a second generation gas chemical laser to follow the first HF/DF chemical laser. However, a COIL releases large amounts of gas, such as helium, oxygen, chlorine and iodine. Chlorides have a serious corrosive effect on the system, especially iodine vapor crystallization, which seriously endangers the normal use of vacuum systems, and radioactive methyl iodide, which is hazardous to operators and pollutes the environment. The use of soaked coal-based activated carbon as an adsorbent for removing methyl iodine is proposed, while it is proposed that coal-based activated carbon is an effective adsorbent for removing stable iodine. The research conducted in this work shows that iodine residues are less than 0.5 μg ml-1 after the adsorption treatment and the decontamination factor of the coal-based activated carbon for removing stable iodine is more than 1000. Using this method can achieve the purpose of removing harmful iodine, satisfy the requirements for engineering applications, and also be applied to other nuclear power plant flue gas treatments.

  19. Adsorption and revaporisation studies on iodine oxide aerosols deposited on containment surface materials in LWR

    Energy Technology Data Exchange (ETDEWEB)

    Tietze, S.; Foreman, M.R.StJ.; Ekberg, C. [Chalmers Univ. of Technology, Goeteborg (Sweden); Kaerkelae, T.; Auvinen, A.; Tapper, U.; Lamminmaeki, S.; Jokiniemi, J. [VTT Technical Research Centre of Finland, Espoo (Finland)

    2012-12-15

    During a hypothetical severe nuclear accident, the radiation field will be very high in the nuclear reactor containment building. As a result gaseous radiolysis products will be formed. Elemental iodine can react in the gaseous phase with ozone to form solid iodine oxide aerosol particles (iodine oxide). Within the AIAS (Adsorption of Iodine oxide Aerosols on Surfaces) project the interactions of iodine oxide (IOx) aerosols with common containment surface materials were investigated. Common surface materials in Swedish and Finnish LWRs are Teknopox Aqua V A paint films and metal surfaces such as Cu, Zn, Al and SS, as well as Pt and Pd surfaces from hydrogen recombiners. Non-radioactive and {sup 131}I labelled iodine oxide aerosols were produced with the EXSI CONT facility from elemental iodine and ozone at VTT Technical Research Centre of Finland. The iodine oxide deposits were analysed with microscopic and spectroscopic measurement techniques to identify the kind of iodine oxide formed and if a chemical conversion on the different surface materials occurs. The revaporisation behaviour of the deposited iodine oxide aerosol particles from the different surface materials was studied under the influence of heat, humidity and gamma irradiation at Chalmers University of Technology, Sweden. Studies on the effects of humidity were performed using the FOMICAG facility, while heat and irradiation experiments were performed in a thermostated heating block and with a gammacell 22 having a dose rate of 14 kGy/h. The revaporisation losses were measured using a HPGe detector. The revaporisated {sup 131}I species from the surfaces were chemically tested for elemental iodine formation. The parameter dominating the degradation of the produced iodine oxide aerosols was humidity. Cu and Zn surfaces were found to react with iodine from the iodine oxide aerosols to form iodides, while no metal iodides were detected for Al and SS samples. Most of the iodine oxide aerosols are assumed to

  20. Adsorption and revaporisation studies on iodine oxide aerosols deposited on containment surface materials in LWR

    International Nuclear Information System (INIS)

    Tietze, S.; Foreman, M.R.StJ.; Ekberg, C.; Kaerkelae, T.; Auvinen, A.; Tapper, U.; Lamminmaeki, S.; Jokiniemi, J.

    2012-12-01

    During a hypothetical severe nuclear accident, the radiation field will be very high in the nuclear reactor containment building. As a result gaseous radiolysis products will be formed. Elemental iodine can react in the gaseous phase with ozone to form solid iodine oxide aerosol particles (iodine oxide). Within the AIAS (Adsorption of Iodine oxide Aerosols on Surfaces) project the interactions of iodine oxide (IOx) aerosols with common containment surface materials were investigated. Common surface materials in Swedish and Finnish LWRs are Teknopox Aqua V A paint films and metal surfaces such as Cu, Zn, Al and SS, as well as Pt and Pd surfaces from hydrogen recombiners. Non-radioactive and 131 I labelled iodine oxide aerosols were produced with the EXSI CONT facility from elemental iodine and ozone at VTT Technical Research Centre of Finland. The iodine oxide deposits were analysed with microscopic and spectroscopic measurement techniques to identify the kind of iodine oxide formed and if a chemical conversion on the different surface materials occurs. The revaporisation behaviour of the deposited iodine oxide aerosol particles from the different surface materials was studied under the influence of heat, humidity and gamma irradiation at Chalmers University of Technology, Sweden. Studies on the effects of humidity were performed using the FOMICAG facility, while heat and irradiation experiments were performed in a thermostated heating block and with a gammacell 22 having a dose rate of 14 kGy/h. The revaporisation losses were measured using a HPGe detector. The revaporisated 131 I species from the surfaces were chemically tested for elemental iodine formation. The parameter dominating the degradation of the produced iodine oxide aerosols was humidity. Cu and Zn surfaces were found to react with iodine from the iodine oxide aerosols to form iodides, while no metal iodides were detected for Al and SS samples. Most of the iodine oxide aerosols are assumed to be

  1. X-ray Pump–Probe Investigation of Charge and Dissociation Dynamics in Methyl Iodine Molecule

    Directory of Open Access Journals (Sweden)

    Li Fang

    2017-05-01

    Full Text Available Molecular dynamics is of fundamental interest in natural science research. The capability of investigating molecular dynamics is one of the various motivations for ultrafast optics. We present our investigation of photoionization and nuclear dynamics in methyl iodine (CH3I molecule with an X-ray pump X-ray probe scheme. The pump–probe experiment was realized with a two-mirror X-ray split and delay apparatus. Time-of-flight mass spectra at various pump–probe delay times were recorded to obtain the time profile for the creation of high charge states via sequential ionization and for molecular dissociation. We observed high charge states of atomic iodine up to 29+, and visualized the evolution of creating these high atomic ion charge states, including their population suppression and enhancement as the arrival time of the second X-ray pulse was varied. We also show the evolution of the kinetics of the high charge states upon the timing of their creation during the ionization-dissociation coupled dynamics. We demonstrate the implementation of X-ray pump–probe methodology for investigating X-ray induced molecular dynamics with femtosecond temporal resolution. The results indicate the footprints of ionization that lead to high charge states, probing the long-range potential curves of the high charge states.

  2. Dynamics of production of iodine atoms by dissociation of iodides in a pulsed self-sustained discharge

    International Nuclear Information System (INIS)

    Vagin, Nikolai P; Kochetov, Igor' V; Napartovich, A P; Yuryshev, Nikolai N

    2013-01-01

    Absorption at the laser transition has been used for the first time to assess the evolution of concentration of iodine atoms in a pulsed self-sustained discharge in mixtures of iodides with a buffer gas such as molecular nitrogen and helium. Dynamics of the iodine atom production is studied by the method of absorption spectroscopy. The dissociation of C n F 2n+1 I and CnH 2n+1 I (n = 1, 2) iodides is investigated. The energy required to produce atomic iodine is evaluated. The experimental data obtained for CF 3 I are compared with the results of numerical simulations, their reasonable agreement being demonstrated. (active media)

  3. First-principles study of H2 adsorption and dissociation on Zr(0 0 0 1)

    International Nuclear Information System (INIS)

    Zhang Peng; Wang Shuangxi; Zhao Jian; He Chaohui; Zhang Ping

    2011-01-01

    Highlights: → The stability of the equilibrium adsorption states is determined after the geometry optimization. → The origin of the stable chemisorbed state is analyzed by the electronic structure and charge redistribution calculation. → The dissociation energetics of H2 are investigated in details by the PES and CINEB calculation. - Abstract: The adsorption and dissociation of H 2 molecules on the Zr(0 0 0 1) surface are systematically investigated by using density functional theory within the generalized gradient approximation and a supercell approach. After geometry optimization, the most stable equilibrium adsorption state is found to be along the top-y entrance. By calculating the adiabatic potential energy surface, the chemisorbed molecular adsorption states are also identified to be along the parallel channel at the top site. The electronic properties of the stable chemisorbed molecular state are analyzed, which show that the interaction between the molecule and substrate is of covalent characteristic with a sizeable charge redistribution. On the other hand, the hcp site is turned out to be the most stable equilibrium adsorption site for hydrogen atom on Zr(0 0 0 1) surface after the dissociation of H 2 . The dissociation energetics of H 2 are studied by calculating the potential energy surface and the minimum energy path of the transition state is determined by using the climb image nudged elastic band method, wherein the fcc-y channel is found to be most stable and favorable for dissociative adsorption of H 2 among the five possible dissociative paths. Remarkably, we find that the adiabatic dissociation process of H 2 is an activated type but with a small energy barrier, which is well consistent with the macroscopic phenomenon that the zirconium metal is easily hydrogenated.

  4. Dynamics of dissociative adsorption of hydrogen on Ni(100)

    International Nuclear Information System (INIS)

    Hamza, A.V.; Madix, R.J.

    1985-01-01

    Nearly monoenergetic beams of hydrogen and deuterium were used to determine dissociative sticking probabilities for H 2 and D 2 on Ni(100) at various energies. Variation of the surface temperature between 90 and 300 K had no effect on the dissociative sticking probability of H 2 at 3.6 and 5.8 kJ/mol incident beam energy, indicating a direct mechanism of dissociation. A four fold increase in the initial dissociative sticking probability for H 2 from 0.2 to 0.8 was observed by increasing the translational kinetic energy from 0.7 to 7.0 kJ/mol. The initial dissociative sticking probability for D 2 was slightly lower, increasing from 0.15 to 0.75 with increasing translational kinetic energy from 1.3 to 10.5 kJ/mol. The form of the increase with kinetic energy was explained by tunnelling through a low activation barrier, accounting as well for the high dissociation probability at low kinetic energies. The dissociative sticking probability decreased with hydrogen or deuterium adatom coverage at all energies. The decline in sticking probability with hydrogen coverage was fit to a s(theta) = s 0 (1 - a theta)/sup n/ functional form. From this relationship it was deduced that hydrogen adatoms block only single sites and that four vacant sites are needed for dissociation. The dissociative sticking probability for H 2 declined precipitously from 0.77 to 0.16 with oxygen adatom coverage from 0 to 5% of a monolayer at a translational energy of 9.6 kJ.mol. 36 references, 8 figures

  5. The I2 dissociation mechanisms in the chemical oxygen-iodine laser revisited.

    Science.gov (United States)

    Waichman, K; Barmashenko, B D; Rosenwaks, S

    2012-06-28

    The recently suggested mechanism of I(2) dissociation in the chemical oxygen-iodine laser (COIL) [K. Waichman, B. D. Barmashenko, and S. Rosenwaks, J. Appl. Phys. 106, 063108 (2009); and J. Chem. Phys. 133, 084301 (2010)] was largely based on the suggestion of V. N. Azyazov, S. Yu. Pichugin, and M. C. Heaven [J. Chem. Phys. 130, 104306 (2009)] that the vibrational population of O(2)(a) produced in the chemical generator is high enough to play an essential role in the dissociation. The results of model calculations based on this mechanism agreed very well with measurements of the small signal gain g, I(2) dissociation fraction F, and temperature T in the COIL. This mechanism is here revisited, following the recent experiments of M. V. Zagidullin [Quantum Electron. 40, 794 (2010)] where the observed low population of O(2)(b, v = 1) led to the conclusion that the vibrational population of O(2)(a) at the outlet of the generator is close to thermal equilibrium value. This value corresponds to a very small probability, ∼0.05, of O(2)(a) energy pooling to the states O(2)(X,a,b, v > 0). We show that the dissociation mechanism can reproduce the experimentally observed values of g, F, and T in the COIL only if most of the energy released in the processes of O(2)(a) energy pooling and O(2)(b) quenching by H(2)O ends up as vibrational energy of the products, O(2)(X,a,b), where the vibrational states v = 2 and 3 are significantly populated. We discuss possible reasons for the differences in the suggested vibrational population and explain how these differences can be reconciled.

  6. Organic Iodine Adsorption by AgZ under Prototypical Vessel Off-Gas Conditions

    International Nuclear Information System (INIS)

    Bruffey, Stephanie H.; Jubin, Robert Thomas; Jordan, J. A.

    2016-01-01

    U.S. regulations will require the removal of 129 I from the off-gas streams of any used nuclear fuel (UNF) reprocessing plant prior to discharge of the off-gas to the environment. Multiple off-gas streams within a UNF reprocessing plant combine prior to release, and each of these streams contains some amount of iodine. For an aqueous UNF reprocessing plant, these streams include the dissolver off-gas, the cell off-gas, the vessel off-gas (VOG), the waste off-gas and the shear off-gas. To achieve regulatory compliance, treatment of multiple off-gas streams within the plant must be performed. Preliminary studies have been completed on the adsorption of I 2 onto silver mordenite (AgZ) from prototypical VOG streams. The study reported that AgZ did adsorb I 2 from a prototypical VOG stream, but process upsets resulted in an uneven feed stream concentration. The experiments described in this document both improve the characterization of I 2 adsorption by AgZ from dilute gas streams and further extend it to include characterization of the adsorption of organic iodides (in the form of CH 3 I) onto AgZ under prototypical VOG conditions. The design of this extended duration testing was such that information about the rate of adsorption, the penetration of the iodine species, and the effect of sorbent aging on iodine removal in VOG conditions could be inferred.

  7. X-ray photoelectron and Auger electron spectroscopic study of the adsorption of molecular iodine on uranium metal and uranium dioxide

    International Nuclear Information System (INIS)

    Dillard, J.G.; Moers, H.; Klewe-Nebenius, H.; Kirch, G.; Pfennig, G.; Ache, H.J.

    1984-01-01

    The adsorption of molecular iodine on uranium metal and on uranium dioxide has been investigated at 25 0 C. Clean surfaces were prepared in an ultrahigh vacuum apparatus and were characterized by X-ray photoelectron (XPS) and X-ray and electron-induced Auger electron spectroscopies (AES). Adsorption of I 2 was studied for exposures up to 100 langmuirs (1 langmuir = 10 -6 torr s) on uranium metal and to 75 langmuirs on uranium dioxide. Above about 2-langmuir I 2 exposure on uranium, spectroscopic evidence is obtained to indicate the beginning of UI 3 formation. Saturation coverage for I 2 adsorption on uranium dioxide occurs at approximately 10-15 langmuirs. Analysis of the XPS and AES results as well as studies of spectra as a function of temperature lead to the conclusions that a dissociative chemisorption/reaction process occurs on uranium metal while nondissociative adsorption occurs on uranium dioxide. Variations in the iodine Auger kinetic energy and in the Auger parameter are interpreted in light of extra-atomic relaxation processes. 42 references, 10 figures, 1 table

  8. Automatic Method for Controlling the Iodine Adsorption Number in Carbon Black Oil Furnaces

    Directory of Open Access Journals (Sweden)

    Zečević, N.

    2008-12-01

    Full Text Available There are numerous of different inlet process factors in carbon black oil furnaces which must be continuously and automatically adjusted, due to stable quality of final product. The most important six inlet process factors in carbon black oil-furnaces are:1. volume flow of process air for combustion2. temperature of process air for combustion3. volume flow of natural gas for insurance the necessary heat for thermal reaction of conversionthe hydrocarbon oil feedstock in oil-furnace carbon black4. mass flow rate of hydrocarbon oil feedstock5. type and quantity of additive for adjustment the structure of oil-furnace carbon black6. quantity and position of the quench water for cooling the reaction of oil-furnace carbon black.The control of oil-furnace carbon black adsorption capacity is made with mass flow rate of hydrocarbon feedstock, which is the most important inlet process factor. Oil-furnace carbon black adsorption capacity in industrial process is determined with laboratory analyze of iodine adsorption number. It is shown continuously and automatically method for controlling iodine adsorption number in carbon black oil-furnaces to get as much as possible efficient control of adsorption capacity. In the proposed method it can be seen the correlation between qualitatively-quantitatively composition of the process tail gasses in the production of oil-furnace carbon black and relationship between air for combustion and hydrocarbon feedstock. It is shown that the ratio between air for combustion and hydrocarbon oil feedstock is depended of adsorption capacity summarized by iodine adsorption number, regarding to BMCI index of hydrocarbon oil feedstock.The mentioned correlation can be seen through the figures from 1. to 4. From the whole composition of the process tail gasses the best correlation for continuously and automatically control of iodine adsorption number is show the volume fraction of methane. The volume fraction of methane in the

  9. Adsorption and dissociation of dinitrogen on transition metal (Ta, W and Re) doped MgO surface

    KAUST Repository

    Yadav, Manoj Kumar

    2016-06-16

    The adsorption and dissociation of dinitrogen on transition metal (Ta, W and Re) doped MgO(100) surface has been studied employing density functional theory. It is found that all these transition metals (TM) on MgO(100) surface are capable of adsorbing dinitrogen (N2), however there is no dissociative adsorption of N2 on single transition metal dopant. When two TM atoms are doped on MgO(100) surface, dissociative adsorption of dinitrogen occurs in all the three cases. Whether the dissociation is spontaneous or is it associated with activation barrier depends on the orientation of N2 molecule approaching the dopant site.

  10. Iodine adsorption on ion-exchange resins and activated carbons: batch testing

    Energy Technology Data Exchange (ETDEWEB)

    Parker, Kent E.; Golovich, Elizabeth C.; Wellman, Dawn M.

    2014-09-30

    Iodine sorption onto seven resins and six carbon materials was evaluated using water from well 299-W19-36 on the Hanford Site. These materials were tested using a range of solution-to-solid ratios. The test results are as follows. The efficacy of the resin and granular activated carbon materials was less than predicted based on manufacturers’ performance data. It is hypothesized that this is due to the differences in speciation previously determined for Hanford groundwater. The sorption of iodine is affected by the iodine species in the source water. Iodine loading on resins using source water ranged from 1.47 to 1.70 µg/g with the corresponding Kd values from 189.9 to 227.0 mL/g. The sorption values when the iodine is converted to iodide ranged from 2.75 to 5.90 µg/g with the corresponding Kd values from 536.3 to 2979.6 mL/g. It is recommended that methods to convert iodine to iodide be investigated in fiscal year (FY) 2015. The chemicals used to convert iodine to iodate adversely affected the sorption of iodine onto the carbon materials. Using as-received source water, loading and Kd values ranged from 1.47 to 1.70 µg/g and 189.8 to 226.3 mL/g respectively. After treatment, loading and Kd values could not be calculated because there was little change between the initial and final iodine concentration. It is recommended the cause of the decrease in iodine sorption be investigated in FY15. In direct support of CH2M HILL Plateau Remediation Company, Pacific Northwest National Laboratory has evaluated samples from within the 200W pump and treat bioreactors. As part of this analysis, pictures taken within the bioreactor reveal a precipitate that, based on physical properties and known aqueous chemistry, is hypothesized to be iron pyrite or chalcopyrite, which could affect iodine adsorption. It is recommended these materials be tested at different solution-to-solid ratios in FY15 to determine their effect on iodine

  11. Iodine adsorption on ion-exchange resins and activated carbons: batch testing

    International Nuclear Information System (INIS)

    Parker, Kent E.; Golovich, Elizabeth C.; Wellman, Dawn M.

    2014-01-01

    Iodine sorption onto seven resins and six carbon materials was evaluated using water from well 299-W19-36 on the Hanford Site. These materials were tested using a range of solution-to-solid ratios. The test results are as follows. The efficacy of the resin and granular activated carbon materials was less than predicted based on manufacturers' performance data. It is hypothesized that this is due to the differences in speciation previously determined for Hanford groundwater. The sorption of iodine is affected by the iodine species in the source water. Iodine loading on resins using source water ranged from 1.47 to 1.70 µg/g with the corresponding K d values from 189.9 to 227.0 mL/g. The sorption values when the iodine is converted to iodide ranged from 2.75 to 5.90 µg/g with the corresponding K d values from 536.3 to 2979.6 mL/g. It is recommended that methods to convert iodine to iodide be investigated in fiscal year (FY) 2015. The chemicals used to convert iodine to iodate adversely affected the sorption of iodine onto the carbon materials. Using as-received source water, loading and K d values ranged from 1.47 to 1.70 µg/g and 189.8 to 226.3 mL/g respectively. After treatment, loading and K d values could not be calculated because there was little change between the initial and final iodine concentration. It is recommended the cause of the decrease in iodine sorption be investigated in FY15. In direct support of CH2M HILL Plateau Remediation Company, Pacific Northwest National Laboratory has evaluated samples from within the 200W pump and treat bioreactors. As part of this analysis, pictures taken within the bioreactor reveal a precipitate that, based on physical properties and known aqueous chemistry, is hypothesized to be iron pyrite or chalcopyrite, which could affect iodine adsorption. It is recommended these materials be tested at different solution-to-solid ratios in FY15 to determine their effect on iodine sorption.

  12. Adsorption modes of molecular iodine on defected boron nitrides: A DFT study

    Science.gov (United States)

    Arabieh, Masoud; Azar, Yavar Taghipour

    2018-03-01

    The interaction of molecular iodine with pristine and monovacant boron-nitride quantum dots (QDs) have been investigated using density functional theory. It was found that removing one B or N single atom significantly decreased the calculated Eg values at various exchange functional. In B-defected BN system, the localized spin densities canceled each other and overall polarization of system was found to be equal to unity. For N-defected system there was smaller spin densities localized on each closest B atoms. Both B- and N-vacancies caused appearance of new states in gap region. Our calculation revealed that spin density and polarization of defected system are localized on vacancy region and other atoms did not take part in this polarization. The results of electron localization function for N-DBN showed there was high density region at the position of removed nitrogen atom. The calculated adsorption energies implied that there was no significant chemical interaction between iodine molecule and pristine BN sheet. We suggested that when a deficiency was imposed to the BN sheet, the reactivity of the modified system toward iodine molecule significantly could increase. We found strong interaction between iodine and nitrogen atoms of B-DBN system. In the case of I2/N-DBN system the neighbor atoms had no contribution in spin polarization of the system and it seemed that all spin density of system transferred to the iodine molecule after adsorption. Strong correlation between molecular iodine orientation and BN-QDs via their interactions type has been clarified in this work. These findings may provide a deeper insight into halogen molecules interactions with low dimensional defected boron nitrides.

  13. Modification of the properties of porous silicon on adsorption of iodine molecules

    International Nuclear Information System (INIS)

    Vorontsov, A. S.; Osminkina, L. A.; Tkachenko, A. E.; Konstantinova, E. A.; Elenskii, V. G.; Timoshenko, V. Yu.; Kashkarov, P. K.

    2007-01-01

    Infrared spectroscopy and electron spin resonance measurements are used to study the properties of porous silicon layers on adsorption of the I 2 iodine molecules. The layers are formed on the p-an n-Si single-crystal wafers. It is established that, in the atmosphere of I 2 molecules, the charge-carrier concentration in the layers produced on the p-type wafers can be noticeably increased: the concentration of holes can attain values on the order of ∼10 18 -10 19 cm -3 . In porous silicon layers formed on the n-type wafers, the adsorption-induced inversion of the type of charge carriers and the partial substitution of silicon-hydrogen bonds by silicon-iodine bonds are observed. A decrease in the concentration of surface paramagnetic defects, P b centers, is observed in the samples with adsorbed iodine. The experimental data are interpreted in the context of the model in which it is assumed that both deep and shallow acceptor states are formed at the surface of silicon nanocrystals upon the adsorption of I 2 molecules

  14. Density function theory study of the adsorption and dissociation of carbon monoxide on tungsten nanoparticles.

    Science.gov (United States)

    Weng, Meng-Hsiung; Ju, Shin-Pon; Chen, Hsin-Tsung; Chen, Hui-Lung; Lu, Jian-Ming; Lin, Ken-Huang; Lin, Jenn-Sen; Hsieh, Jin-Yuan; Yang, Hsi-Wen

    2013-02-01

    The adsorption and dissociation properties of carbon monoxide (CO) molecule on tungsten W(n) (n = 10-15) nanoparticles have been investigated by density-functional theory (DFT) calculations. The lowest-energy structures for W(n) (n = 10-15) nanoparticles are found by the basin-hopping method and big-bang method with the modified tight-binding many-body potential. We calculated the corresponding adsorption energies, C-O bond lengths and dissociation barriers for adsorption of CO on nanoparticles. The electronic properties of CO on nanoparticles are studied by the analysis of density of state and charge density. The characteristic of CO on W(n) nanoparticles are also compared with that of W bulk.

  15. Strain effect on the adsorption, diffusion, and molecular dissociation of hydrogen on Mg (0001) surface

    Energy Technology Data Exchange (ETDEWEB)

    Lei, Huaping; Wang, Caizhuang; Yao, Yongxin; Hupalo, Myron [Ames Laboratory, USDOE, Ames, Iowa 50011 (United States); Wang, Yangang [Ames Laboratory, USDOE, Ames, Iowa 50011 (United States); Supercomputing Center of Computer Network Information Center, CAS, Beijing 100190 (China); McDougall, Dan; Tringides, Michael; Ho, Kaiming [Ames Laboratory, USDOE, Ames, Iowa 50011 (United States); Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States)

    2013-12-14

    The adsorption, diffusion, and molecular dissociation of hydrogen on the biaxially strained Mg (0001) surface have been systematically investigated by the first principle calculations based on density functional theory. When the strain changes from the compressive to tensile state, the adsorption energy of H atom linearly increases while its diffusion barrier linearly decreases oppositely. The dissociation barrier of H{sub 2} molecule linearly reduces in the tensile strain region. Through the chemical bonding analysis including the charge density difference, the projected density of states and the Mulliken population, the mechanism of the strain effect on the adsorption of H atom and the dissociation of H{sub 2} molecule has been elucidated by an s-p charge transfer model. With the reduction of the orbital overlap between the surface Mg atoms upon the lattice expansion, the charge transfers from p to s states of Mg atoms, which enhances the hybridization of H s and Mg s orbitals. Therefore, the bonding interaction of H with Mg surface is strengthened and then the atomic diffusion and molecular dissociation barriers of hydrogen decrease accordingly. Our works will be helpful to understand and to estimate the influence of the lattice deformation on the performance of Mg-containing hydrogen storage materials.

  16. The adsorption and dissociation of water molecule on goethite (010) surface: A DFT approach

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Long, E-mail: shuweixia@ouc.edu.cn [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, College of Chemistry and Chemical Engineering (China); Xiu, Fangyuan [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, College of Chemistry and Chemical Engineering (China); Qiu, Meng [Qingdao Institute of Bioenergy and Bioprocess Technology (China); Xia, Shuwei; Yu, Liangmin [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, College of Chemistry and Chemical Engineering (China)

    2017-01-15

    Graphical abstract: The optimized structure of hydrated goethite (010) surface with medium water coverage (water density about 6.7 H{sub 2}O/nm{sup 2}). - Highlights: • Stable adsorption and dissociation structure of H{sub 2}O on goethite (010) surface was investigated by DFT. • Reasonable path for water dissociation was proposed by transitional state analysis. • The mechanism of water adsorption on goethite and binding nature were revealed by PDOS. - Abstract: Using density functional theory (DFT) calculation, we investigate the configuration, stability and electronic properties of fresh cleaved (010) goethite surface (Pnma) and this surface exposed to water monolayer at low, medium and high coverage. Water is predicted to be chemisorbed to the surface, together with the surface reconstruction. The interaction energy of the most stable configuration of both low and medium coverage per water molecule is almost the same (−1.17 eV), while that of high coverage is much lower (less than 1.03 eV). It indicates that highly hydrated surface is less stable. PDOS analysis reveals the adsorption of H{sub 2}O is due to the formation of Fe−O bond, caused by overlapping of Fe's 3d and O's 2p orbitals. Dissociation processes at low and medium water coverage are non-spontaneous; while at high coverage, it can undertake spontaneously both thermodynamically and dynamically. The dissociation paths of all three water coverage are the similar. The proton from one adsorbed water is likely to dissociate to bind to the vicinal surface μ{sub 3}−O as an intermediate product; the proton belonged to μ{sub 3}−O transferred to the neighbor surface μ{sub 2}−O as the dissociative configuration.

  17. Size effect on the adsorption and dissociation of CO{sub 2} on Co nanoclusters

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Haiyan; Cao, Dapeng; Fisher, Adrian [International Research Center for Soft Matter, State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Johnston, Roy L. [School of Chemistry, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom); Cheng, Daojian, E-mail: chengdj@mail.buct.edu.cn [International Research Center for Soft Matter, State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China)

    2017-02-28

    Highlights: • Co{sub 13}, Co{sub 38} and Co{sub 55} nanoclusters were predicted as the high-symmetry structures. • CO{sub 2} dissociation on the size-selected Co{sub 13}, Co{sub 38} and Co{sub 55} nanoclusters was studied. • Co{sub 55} nanocluster possesses the highest activity relevant to CO{sub 2} dissociation. • A non-monotonous behavior of the dissociation barrier of CO{sub 2} with the size was found. - Abstract: Spin-polarized density functional theory calculations were carried out to study the adsorption and dissociation properties of CO{sub 2} on size-selected Co{sub 13}, Co{sub 38} and Co{sub 55} nanoclusters. Based on genetic algorithm method, Co{sub 13}, Co{sub 38} and Co{sub 55} nanoclusters were predicted as the most stable high-symmetry structures among these Co{sub n} (n = 2–58) nanoclusters from the Gupta potential. For the adsorption of CO{sub 2}, CO and O on size-selected Co{sub 13}, Co{sub 38} and Co{sub 55} nanoclusters, the lowest adsorption strength is found for all the different adsorbates on Co{sub 55} nanocluster. For the dissociation of CO{sub 2} on these size-selected Co nanoclusters, the largest Co{sub 55} nanocluster possesses the greatest catalytic activity for the dissociation of CO{sub 2}, with the smallest reaction barrier of 0.38 eV. Our results reveal a non-monotonous behavior of the catalytic activities of Co nanoclusters on size, which is of fundamental interest for the design of new Co catalysts for the conversion of CO{sub 2}.

  18. Organic Iodine Adsorption by AgZ under Prototypical Vessel Off-Gas Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Bruffey, Stephanie H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jubin, Robert Thomas [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jordan, J. A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-30

    U.S. regulations will require the removal of 129I from the off-gas streams of any used nuclear fuel (UNF) reprocessing plant prior to discharge of the off-gas to the environment. Multiple off-gas streams within a UNF reprocessing plant combine prior to release, and each of these streams contains some amount of iodine. For an aqueous UNF reprocessing plant, these streams include the dissolver off-gas, the cell off-gas, the vessel off-gas (VOG), the waste off-gas and the shear off-gas. To achieve regulatory compliance, treatment of multiple off-gas streams within the plant must be performed. Preliminary studies have been completed on the adsorption of I2 onto silver mordenite (AgZ) from prototypical VOG streams. The study reported that AgZ did adsorb I2 from a prototypical VOG stream, but process upsets resulted in an uneven feed stream concentration. The experiments described in this document both improve the characterization of I2 adsorption by AgZ from dilute gas streams and further extend it to include characterization of the adsorption of organic iodides (in the form of CH3I) onto AgZ under prototypical VOG conditions. The design of this extended duration testing was such that information about the rate of adsorption, the penetration of the iodine species, and the effect of sorbent aging on iodine removal in VOG conditions could be inferred.

  19. Iodine

    Science.gov (United States)

    ... Health Information Supplement Fact Sheets Frequently Asked Questions Making Decisions What you Need To Know About Supplements Dietary ... mild iodine deficiency and of iodine supplements on cognitive ... breasts. It mainly affects women of reproductive age but can also occur ...

  20. Insights into the effect of coverage on CO adsorption and dissociation over Rh(1 0 0) surface: A theoretical study

    International Nuclear Information System (INIS)

    Zhao, Xiaojun; Zhang, Riguang; Ling, Lixia; Wang, Baojun

    2014-01-01

    Graphical abstract: - Highlights: • The adsorption energies gradually decrease with the increasing of CO coverage on Rh(1 0 0). • CO reaches the saturated adsorption with the coverage of 12/12 ML on Rh(1 0 0). • Both CO desorption and dissociation co-exist at the coverage less than or equal to 2/12 ML. • Only molecule CO adsorption is favored at the coverage greater than or equal to 3/12 ML. • Only molecule CO adsorption form exists in syngas conversion on Rh catalyst. - Abstract: The adsorption, dissociation and desorption of CO at different coverage over Rh(1 0 0) surface have been systematically investigated using density functional theory method together with the periodic slab model. Our results show that at the coverage less than or equal to 4/12 ML, CO favored the most stable bridge site adsorption, and the adsorption energies of CO have little difference; while at the coverage greater than or equal to 5/12 ML, the lateral repulsive interaction begins to affect the adsorption structures and the corresponding adsorption energies of adsorbed CO molecules, and the interaction will be stronger with the increasing of CO coverage, which leads to CO migration over Rh(1 0 0) surface when CO coverage is greater than or equal to 10/12 ML. The adsorption energies of these CO molecules will decrease successively until the saturated adsorption with the CO coverage of 12/12 ML. Further calculations on CO dissociation indicate that when CO coverage is greater than or equal to 3/12 ML, the dissociation of adsorbed CO molecules will be unfavorable both kinetically and thermodynamically, suggesting that only molecule CO adsorption are favored. Considering the catalytic activity of Rh(1 0 0) surface toward CO dissociation and the higher CO coverage under the continuous supply of CO in syngas conversion, it is to be expected that only molecule CO adsorption exist on Rh catalyst

  1. A density functional study on adsorption and dissociation of O 2 on Ir(1 0 0) surface

    Science.gov (United States)

    Erikat, I. A.; Hamad, B. A.; Khalifeh, J. M.

    2011-06-01

    The adsorption and the reaction barrier for the dissociation of O 2 on Ir(1 0 0) surface are studied using periodic self-consistent density functional theory (DFT) calculations. Dissociative adsorption is found to be energetically more favorable compared to molecular adsorption. Parallel approaches Prl1 and Prl2 on a hollow site with the same adsorption energy of -3.93 eV for both of them are found to have the most energetically preferred sites of adsorptions among all the studied cases. Hybridization between p-O 2 and d-metal orbitals is responsible for the dissociative adsorption. The minimum energy path is determined by using the nudge elastic band method (NEB). We found that the dissociation occurs immediately and very early in the dissociation path with a small activation barrier (0.26 eV), which means that molecular adsorption of O 2 on Ir(1 0 0) surface occurs at very low temperatures; this is consistent with previous experimental and theoretical studies on Ir surfaces.

  2. Adsorption and dissociation of oxygen molecules on Si(111)-(7×7) surface

    International Nuclear Information System (INIS)

    Niu, Chun-Yao; Wang, Jian-Tao

    2013-01-01

    The adsorption and dissociation of O 2 molecules on Si(111)-(7×7) surface have been studied by first-principles calculations. Our results show that all the O 2 molecular species adsorbed on Si(111)-(7×7) surface are unstable and dissociate into atomic species with a small energy barrier about 0.1 eV. The single O 2 molecule adsorption tends to form an ins×2 or a new metastable ins×2* structure on the Si adatom sites and the further coming O 2 molecules adsorb on those structures to produce an ad-ins×3 structure. The ad-ins×3 structure is indeed highly stable and kinetically limited for diving into the subsurface layer to form the ins×3-tri structure by a large barrier of 1.3 eV. Unlike the previous views, we find that all the ad-ins, ins×2, and ad-ins×3 structures show bright images, while the ins×2*, ins×3, and ins×3-tri structures show dark images. The proposed oxidation pathways and simulated scanning tunneling microscope images account well for the experimental results and resolve the long-standing confusion and issue about the adsorption and reaction of O 2 molecules on Si(111) surface

  3. Iodine

    Science.gov (United States)

    ... leg ulcers and reduce the chance of a future infection. Conjunctivitis (pinkeye). Research suggests that using eye ... National Institute of Medicine has set Adequate Intake (AI) of iodine for infants: 0 to 6 months, ...

  4. Calorimetric study at different temperatures of iodine adsorption from organic solutions on outgassed 'eta' alumina and bayerite

    International Nuclear Information System (INIS)

    Della Gatta, G.; Stradella, L.; Venturello, G.

    1977-01-01

    The adsorption of iodine from solution in n-pentane at 27 0 C and in cyclohexane at 35 0 C and 50 0 C on eta-Al 2 O 3 and bayerite outgassed at R.T. has been studied with a calorimetric technique. The measurements were performed by means of a Calvet type calorimeter using a new cell conceived for the adsorption from solution. The integral molar energies of adsorption show, at low coverages, a very strong interaction of iodine with surface hydroxyl groups, possibly leading to charge-transfer complexes and reactions. A peculiar exothermic effect has been also evidenced before the monolayer completion, in correspondence with a 'step' on the adsorption isotherms. This result is interpreted in terms of cooperative adsorption implying the possible formation of surface clusters around the strongly absorbed molecules. On non-porous samples (bayerite) the adsorption temperature rise decrease the total amounts adsorbed. But on porous ones (eta-Al 2 O 3 ) the adsorption is increased. (orig./HK) [de

  5. Carbon disulfide (CS{sub 2}) adsorption and dissociation on the Cu(100) surface: A quantum chemical study

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wenju, E-mail: wangwenju1982@163.com; Fan, Lili; Wang, Guoping, E-mail: wgp1976@163.com

    2017-08-31

    Highlights: • CS{sub 2}, CS, C and S are strongly chemadsorbed on the Cu(100) surface. • C/S/S, S/CS and CS{sub 2} accord to a decreased adsorption strength on the Cu(100). • The asymmetric model CS{sub 2}(II) is easier to dissociate on the Cu(100) surface. - Abstract: Density functional theory (DFT) is used to examine the adsorption and dissociation of CS{sub 2} on the Cu(100) surface. This study evaluates the adsorption energies and geometries of the species (CS{sub 2}, CS, C and S) adsorption on the Cu(100) surface, as well as that coadsorption of CS and a S atom, and that coadsorption of C atom and two S atoms. The results indicate that the species (CS{sub 2}, CS, C and S) are strongly chemadsorbed on the Cu(100) surface through the C−Cu and/or S−Cu bond with an increased adsorption energy (C/S/S > S/CS > CS{sub 2}). Two pathways for CS{sub 2} dissociation on the Cu(100) surface are constructed, and the energy barrier and reaction energy of each step are calculated. It shows that the dissociated energy barrier of the second C−S bond is 0.25 eV higher than that of the first C−S bond in the pathway 1, but in the pathway 2, the dissociated energy barrier of the second C−S bond is 0.11 eV lower than that of the first C−S bond. Comparing the highest dissociated energy barrier of pathway 1 (0.68 eV) and pathway 2 (0.5 eV), the structure of S/C/S(II) is regarded as a preferable product for the dissociation of CS{sub 2} on the Cu(100) surface.

  6. Molecular oxygen adsorption and dissociation on Au12M clusters with M = Cu, Ag or Ir

    Science.gov (United States)

    Jiménez-Díaz, Laura M.; Pérez, Luis A.

    2018-03-01

    In this work, we present a density functional theory study of the structural and electronic properties of isolated neutral clusters of the type Au12M, with M = Cu, Ag, or Ir. On the other hand, there is experimental evidence that gold-silver, gold-copper and gold-iridium nanoparticles have an enhanced catalytic activity for the CO oxidation reaction. In order to address these phenomena, we also performed density functional calculations of the adsorption and dissociation of O2 on these nanoparticles. Moreover, to understand the effects of Cu, Ag, and Ir impurity atoms on the dissociation of O2, we also analyze this reaction in the corresponding pure gold cluster. The results indicate that the substitution of one gold atom in a Au13 cluster by Ag, Cu or Ir diminishes the activation energy barrier for the O2 dissociation by nearly 1 eV. This energy barrier is similar for Au12Ag and Au12Cu, whereas for Au12Ir is even lower. These results suggest that the addition of other transition metal atoms to gold nanoclusters can enhance their catalytic activity towards the CO oxidation reaction, independently of the effect that the substrate could have on supported nanoclusters.

  7. Insights on finite size effects in ab initio study of CO adsorption and dissociation on Fe 110 surface

    International Nuclear Information System (INIS)

    Chakrabarty, Aurab; Bouhali, Othmane; Mousseau, Normand; Becquart, Charlotte S.; El-Mellouhi, Fedwa

    2016-01-01

    Adsorption and dissociation of hydrocarbons on metallic surfaces represent crucial steps on the path to carburization, eventually leading to dusting corrosion. While adsorption of CO molecules on Fe surface is a barrier-less exothermic process, this is not the case for the dissociation of CO into C and O adatoms and the diffusion of C beneath the surface that are found to be associated with large energy barriers. In practice, these barriers can be affected by numerous factors that combine to favour the CO-Fe reaction such as the abundance of CO and other hydrocarbons as well as the presence of structural defects. From a numerical point of view, studying these factors is challenging and a step-by-step approach is necessary to assess, in particular, the influence of the finite box size on the reaction parameters for adsorption and dissociation of CO on metal surfaces. Here, we use density functional theory (DFT) total energy calculations with the climbing-image nudged elastic band method to estimate the adsorption energies and dissociation barriers for different CO coverages with surface supercells of different sizes. We further compute the effect of periodic boundary condition for DFT calculations and find that the contribution from van der Waals interaction in the computation of adsorption parameters is important as they contribute to correcting the finite-size error in small systems. The dissociation process involves carbon insertion into the Fe surface causing a lattice deformation that requires a larger surface system for unrestricted relaxation. We show that, in the larger surface systems associated with dilute CO-coverages, C-insertion is energetically more favourable, leading to a significant decrease in the dissociation barrier. This observation suggests that a large surface system with dilute coverage is necessary for all similar metal-hydrocarbon reactions in order to study their fundamental electronic mechanisms, as an isolated phenomenon, free from

  8. Insights on finite size effects in ab initio study of CO adsorption and dissociation on Fe 110 surface

    Energy Technology Data Exchange (ETDEWEB)

    Chakrabarty, Aurab, E-mail: aurab.chakrabarty@qatar.tamu.edu; Bouhali, Othmane [Texas A& M University at Qatar, P.O. Box 23874, Doha (Qatar); Mousseau, Normand [Département de Physique and RQMP, Université de Montréal, Case Postale 6128, Succursale Centre-ville, Montréal, Québec H3C 3J7 (Canada); Becquart, Charlotte S. [UMET, UMR CNRS 8207, ENSCL, Université Lille I, 59655 Villeneuve d' Ascq Cédex (France); El-Mellouhi, Fedwa [Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, P.O. Box 5825, Doha (Qatar)

    2016-08-07

    Adsorption and dissociation of hydrocarbons on metallic surfaces represent crucial steps on the path to carburization, eventually leading to dusting corrosion. While adsorption of CO molecules on Fe surface is a barrier-less exothermic process, this is not the case for the dissociation of CO into C and O adatoms and the diffusion of C beneath the surface that are found to be associated with large energy barriers. In practice, these barriers can be affected by numerous factors that combine to favour the CO-Fe reaction such as the abundance of CO and other hydrocarbons as well as the presence of structural defects. From a numerical point of view, studying these factors is challenging and a step-by-step approach is necessary to assess, in particular, the influence of the finite box size on the reaction parameters for adsorption and dissociation of CO on metal surfaces. Here, we use density functional theory (DFT) total energy calculations with the climbing-image nudged elastic band method to estimate the adsorption energies and dissociation barriers for different CO coverages with surface supercells of different sizes. We further compute the effect of periodic boundary condition for DFT calculations and find that the contribution from van der Waals interaction in the computation of adsorption parameters is important as they contribute to correcting the finite-size error in small systems. The dissociation process involves carbon insertion into the Fe surface causing a lattice deformation that requires a larger surface system for unrestricted relaxation. We show that, in the larger surface systems associated with dilute CO-coverages, C-insertion is energetically more favourable, leading to a significant decrease in the dissociation barrier. This observation suggests that a large surface system with dilute coverage is necessary for all similar metal-hydrocarbon reactions in order to study their fundamental electronic mechanisms, as an isolated phenomenon, free from

  9. Water Adsorption and Dissociation on Ceria-Supported Single-Atom Catalysts: A First-Principles DFT+U Investigation.

    Science.gov (United States)

    Han, Zhong-Kang; Gao, Yi

    2016-02-01

    Single-atom catalysts have attracted wide attention owing to their extremely high atom efficiency and activities. In this paper, we applied density functional theory with the inclusion of the on-site Coulomb interaction (DFT+U) to investigate water adsorption and dissociation on clean CeO 2 (111) surfaces and single transition metal atoms (STMAs) adsorbed on the CeO 2 (111) surface. It is found that the most stable water configuration is molecular adsorption on the clean CeO 2 (111) surface and dissociative adsorption on STMA/CeO 2 (111) surfaces, respectively. In addition, our results indicate that the more the electrons that transfer from STMA to the ceria substrate, the stronger the binding energies between the STMA and ceria surfaces. A linear relationship is identified between the water dissociation barriers and the d band centers of STMA, known as the generalized Brønsted-Evans-Polanyi principle. By combining the oxygen spillovers, single-atom dispersion stabilities, and water dissociation barriers, Zn, Cr, and V are identified as potential candidates for the future design of ceria-supported single-atom catalysts for reactions in which the dissociation of water plays an important role, such as the water-gas shift reaction. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Adsorption and dissociation of dinitrogen on transition metal (Ta, W and Re) doped MgO surface

    KAUST Repository

    Yadav, Manoj Kumar; Vovusha, Hakkim; Sanyal, Biplab

    2016-01-01

    The adsorption and dissociation of dinitrogen on transition metal (Ta, W and Re) doped MgO(100) surface has been studied employing density functional theory. It is found that all these transition metals (TM) on MgO(100) surface are capable

  11. The reaction rate for dissociative adsorption of N-2 on stepped Ru(0001): Six-dimensional quantum calculations

    DEFF Research Database (Denmark)

    van Harrevelt, Rob; Honkala, Johanna Karoliina; Nørskov, Jens Kehlet

    2005-01-01

    Quantum-mechanical calculations of the reaction rate for dissociative adsorption of N-2 on stepped Ru(0001) are presented. Converged six-dimensional quantum calculations for this heavy-atom reaction have been performed using the multiconfiguration time-dependent Hartree method. A potential...

  12. Adsorption and dissociation of Cl{sub 2} molecule on ZnO nanocluster

    Energy Technology Data Exchange (ETDEWEB)

    Beheshtian, Javad [Department of Chemistry, Shahid Rajaee Teacher Training University, P.O. Box: 16875-163, Tehran (Iran, Islamic Republic of); Peyghan, Ali Ahmadi, E-mail: ahmadi.iau@gmail.com [Young Researchers Club, Islamic Azad University, Islamshahr Branch, Tehran (Iran, Islamic Republic of); Bagheri, Zargham [Physics group, Science department, Islamic Azad University, Islamshahr Branch, P.O. Box: 33135-369, Islamshahr, Tehran (Iran, Islamic Republic of)

    2012-08-01

    Adsorption of chlorine molecule (Cl{sub 2}) on the Zn{sub 12}O{sub 12} nano-cage has been analyzed using density functional theory. It has been shown that the Cl{sub 2} molecule is strongly adsorbed on the cluster via two mechanisms including chemisorption and dissociation with Gibbs free energy changes in the range of -0.36 to -0.92 eV at 298 K and 1 atm. These processes also significantly change the electronic properties of cluster by decreasing its HOMO/LUMO energy gap and increasing the work function. The Fermi level shifts towards lower energies upon the interactions between Cl{sub 2} and the cluster, resulting in raised potential barrier of the electron emission for the cluster and hence avoiding the field emission. The Zn{sub 12}O{sub 12} cluster is transformed to a p-type semiconductor substance upon the Cl{sub 2} dissociation. We believe that the obtained results may be helpful in several fields of study such as sensors, catalysts, and field emission investigations.

  13. Adsorption and dissociation of H2S on Mo(1 0 0) surface by first-principles study

    International Nuclear Information System (INIS)

    Luo, Haijun; Cai, Jianqiu; Tao, Xiangming; Tan, Mingqiu

    2014-01-01

    Density-functional theory calculations had been used to investigate the adsorption and dissociation of H 2 S on Mo(1 0 0) surface. Adsorption mechanisms of H 2 S, HS, S and H on the Mo(1 0 0) surface were analyzed. H 2 S was found to be adsorbed at bridge, hollow and top sites with adsorption energies of −1.25, −1.03 and −0.92 eV, respectively. HS was strongly chemically absorbed at hollow, bridge and top sites with adsorption energies of −4.51, −4.08 and −3.45 eV, respectively, and sulfur and hydrogen preferred to be absorbed at hollow and bridge sites, respectively. In addition, potential energy profiles of H 2 S dissociation on Mo(1 0 0) had been constructed by a climbing image nudged elastic band method. Four possible dissociation pathways of the first H 2 S dehydrogenation were examined with reaction barriers of 0.28, 0.37, 0.075, and 0.21 eV, respectively, while the energy barrier to break the S-H bond of HS with or without hydrogen co-adsorption was almost the same low. This work showed that the decomposition of H 2 S on the molybdenum surface was kinetically and thermodynamically facile. Local densities of electronic states were further used to characterize the interaction between H 2 S and substrate.

  14. DFT study of adsorption and dissociation of thiophene molecules on Ni(1 1 0)

    Science.gov (United States)

    Morin, C.; Eichler, A.; Hirschl, R.; Sautet, P.; Hafner, J.

    2003-08-01

    The different adsorption possibilities of thiophene (C 4H 4S) on the Ni(1 1 0) surface have been studied using first principle local-density-functional calculations, with the Vienna ab initio simulation package, which is based on a plane wave basis set and projector augmented wave potentials. For each configuration, a geometric optimisation has been performed. A detailed analysis of the structural and electronic properties of the molecule and the surface in the most stable conformations is presented, showing the combined roles of the molecular distortion and the interactions between the molecule and the surface. Three structures with comparatively large adsorption energies are identified, all with the molecule plane parallel to the surface. Starting from these stabilised structures, various scenarios for the desulfurisation process have been envisaged. While, for the most stable structure, the formation of an adsorbed thiol is an activated process, with an energetic barrier of 0.70 eV, the two structures which are just a bit less stable can dissociate to a C 4H 4 species and a sulfur atom with barriers as low as 0.07 eV. A description of the different transition states and a kinetic analysis of the desulfurisation reaction is also presented.

  15. Adsorption and dissociation of H2O on Al(1 1 1) surface by density functional theory calculation

    International Nuclear Information System (INIS)

    Guo, F.Y.; Long, C.G.; Zhang, J.; Zhang, Z.; Liu, C.H.; Yu, K.

    2015-01-01

    Highlights: • O 2 on Al(1 1 1) surface can spontaneously dissociate, but H 2 O can not. • H 2 O, OH and H on top sites are favorable on Al(1 1 1) surface. • O on the hollow (fcc) site is preferred. • O which plays a key role in the dissociate reaction of H 2 O. - Abstract: Using the first-principles calculations method based on the density functional theory, we systematically study the adsorption behavior of a single molecular H 2 O on a clean and a pre-adsorbed O atom Al(1 1 1) surface, and also its corresponding dissociation reactions. The equilibrium configuration on top, bridge, and hollow (fcc and hcp) site were determined by relaxation of the system relaxation. The adsorptions of H 2 O, OH and H on top sites are favorable on the Al(1 1 1) surface, while that of O on the hollow (fcc) site is preferred. The results show that the hydrogen atom dissociating from H 2 O needs a 248.32 kJ/mol of energy on clean Al(1 1 1) surface, while the dissociating energy decreases to 128.53 kJ/mol with the aid of the O absorption. On the other hand, these phenomena indicate that the dehydrogenated reaction energy barrier of the pre-adsorbed O on metal surface is lower than that of on a clean one, because O can promote the dehydrogenation of H 2 O

  16. Elimination of interference of 129-iodine by its adsorption at extraction separation of 99-technetium

    International Nuclear Information System (INIS)

    Metelkova, M.; Tkac, P.; Kopunec, R.

    2001-01-01

    Three types of macro-amount of anions SO 4 2- , CO 3 2- , OH - in the presence of I- were chosen in this work for comparison of competition with TcO 4 - anions in extraction reaction with Ph 4 As + , where weak, medium and strong competition can be expected respectively. Ph 4 AsCl in chloroform was used as organic phase. The influence of solid AgI or AgCl on Tc extraction was also studied in this extraction systems. The extraction of technetium after four-multiplied extraction from chosen solutions was studied. This procedure was applied in the process of Tc extraction from solutions of reprocessing plant. Various concentrations of K 2 CrO 4 and UO 2 (NO 3 ) 2 in water phase on Tc extraction was investigate, too. The influence of I - ( 131 I) in the process of extraction separation of technetium was studied. The iodine removal was taken out from the solution by its adsorption on insoluble AgI or AgCl phase. The yields for 99m Tc were higher than 95% in organic phase and for 131 I higher than 80% in AgI or AgCl. It is possible to note, that this procedure can be also applied for 99 Tc and 129 I separation and estimation. The results of the extraction are presented in the form of graphical plots of technetium distribution ratio (D Tc , log D Tc ) or extraction yield (E Tc %) against concentration of investigate component in aqueous phase. (authors)

  17. Adsorption and revaporisation studies of thin iodine oxide and CsI aerosol deposits from containment surface materials in LWRs

    Energy Technology Data Exchange (ETDEWEB)

    Tietze, S.; Foreman, M.; Ekberg, C. [Chalmers Univ. of Technology, Goeteborg (Sweden); Kaerkelae, T.; Auvinen, A.; Tapper, U.; Jokiniemi, J. [VTT Technical Research Centre of Finland, Espoo (Finland)

    2013-07-15

    During a severe nuclear accident released fission and radiolysis products can react with each other to form new species which might contribute to the volatile source term. Iodine will be released from UO2 fuel mainly in form as CsI aerosol particles and elemental iodine. Elemental iodine can react in gaseous phase with ozone to form solid iodine oxide aerosol particles (IOx). Within the AIAS-2 (Adsorption of Iodine Aerosols on Surfaces) project the interactions of IOx and CsI aerosols with common containment surface materials was investigated. Common surface materials in Swedish and Finnish LWRs are Teknopox Aqua V A paint films and metal surfaces such as Cu, Zn, Al and SS. Non-radioactive and {sup 131}I labelled aerosols were produced from a KI solution and ozone with a new facility designed and built at VTT Technical Research Centre of Finland. CsI aerosols were produced from a CsI solution with the same facility. A monolayer of the aerosols was deposited on the surfaces. The deposits were analysed with microscopic and spectroscopic measurement techniques to identify the chemical form of the deposits on the surfaces to identify if a chemical conversion on the different surface materials had occured. The revaporisation behaviour of the deposited aerosol particles from the different surface materials was studied under the influence of heat, humidity and gamma irradiation at Chalmers University of Technology, Sweden. Studies on the effects of humidity were performed using the FOMICAG facility, while heat and irradiation experiments were performed in a thermostated heating block and with a gammacell 22 with a dose rate of 14 kGy/h. The revaporisation losses were measured using a HPGe detector. The decomposition effect of the radiolysis product carbon monoxide was tested on IOx aerosols deposited on a glass fibre filter. Iodine oxide particles were produced at 50 deg. C, 100 deg. C and 120 deg. C and deposited on filter samples in order to study the chemical

  18. Adsorption and revaporisation studies of thin iodine oxide and CsI aerosol deposits from containment surface materials in LWRs

    International Nuclear Information System (INIS)

    Tietze, S.; Foreman, M.; Ekberg, C.; Kaerkelae, T.; Auvinen, A.; Tapper, U.; Jokiniemi, J.

    2013-07-01

    During a severe nuclear accident released fission and radiolysis products can react with each other to form new species which might contribute to the volatile source term. Iodine will be released from UO2 fuel mainly in form as CsI aerosol particles and elemental iodine. Elemental iodine can react in gaseous phase with ozone to form solid iodine oxide aerosol particles (IOx). Within the AIAS-2 (Adsorption of Iodine Aerosols on Surfaces) project the interactions of IOx and CsI aerosols with common containment surface materials was investigated. Common surface materials in Swedish and Finnish LWRs are Teknopox Aqua V A paint films and metal surfaces such as Cu, Zn, Al and SS. Non-radioactive and 131 I labelled aerosols were produced from a KI solution and ozone with a new facility designed and built at VTT Technical Research Centre of Finland. CsI aerosols were produced from a CsI solution with the same facility. A monolayer of the aerosols was deposited on the surfaces. The deposits were analysed with microscopic and spectroscopic measurement techniques to identify the chemical form of the deposits on the surfaces to identify if a chemical conversion on the different surface materials had occured. The revaporisation behaviour of the deposited aerosol particles from the different surface materials was studied under the influence of heat, humidity and gamma irradiation at Chalmers University of Technology, Sweden. Studies on the effects of humidity were performed using the FOMICAG facility, while heat and irradiation experiments were performed in a thermostated heating block and with a gammacell 22 with a dose rate of 14 kGy/h. The revaporisation losses were measured using a HPGe detector. The decomposition effect of the radiolysis product carbon monoxide was tested on IOx aerosols deposited on a glass fibre filter. Iodine oxide particles were produced at 50 deg. C, 100 deg. C and 120 deg. C and deposited on filter samples in order to study the chemical speciation of

  19. DFT study of adsorption and dissociation behavior of H2S on Fe-doped graphene

    International Nuclear Information System (INIS)

    Zhang, Hong-ping; Luo, Xue-gang; Song, Hong-tao; Lin, Xiao-yan; Lu, Xiong; Tang, Youhong

    2014-01-01

    Highlights: • Fe-doped and Pt-doped graphene can significantly improve the interactions between H 2 S and graphene. • The location of S had an important role in the interactions between H 2 S and Fe-doped graphene. • The influence of Fe-S distance can be very weak in a certain range and H 2 S can be dissociated into S and H 2 . - Abstracts: Understanding the interaction mechanisms of hydrogen sulfide (H 2 S) with graphene is important in developing graphene-based sensors for gas detection and removal. In this study, the effects of doped Fe atom on interaction of H 2 S with graphene were investigated by density functional theory calculations. Analyses of adsorption energy, electron density difference, and density of states indicated that the doped Fe atom can significantly improve the interaction of H 2 S gas molecules with graphene, as well as Pt-doped graphene. The location of the sulfur atom is important in the interactions between H 2 S and Fe-doped graphene. The influence of the Fe-S distance can be very weak within a certain distance, as simulated in this study

  20. A first principles study of the adsorption and dissociation of CO2 on the δ-Pu (111) surface

    International Nuclear Information System (INIS)

    Atta-Fynn, R.; Raya, A.K.

    2009-01-01

    A complete understanding of the nature of the 5f electrons has been and continues to be a major scientific problem in condensed matter physics. Bulk and surface electronic structure studies of the actinides as also atomic and molecular adsorptions on the actinide surfaces provide a path towards this understanding. In this work, ab initio calculations within the framework of density functional theory have been used to study the adsorption of molecular CO 2 and the corresponding partially dissociated (CO+O) and completely dissociated (C+O+O) products on the δ-Pu (111) surface. The completely dissociated C+O+O configurations exhibit the strongest binding with the surface (7.92 eV), followed by partially dissociated products CO+O (5.08 eV), with molecular CO 2 adsorption having the lowest binding energies (2.35 eV). For all initial vertically upright orientations, the CO 2 molecule physi-sorbs or do not bind to the surface and the geometry and orientation do not change. For all initial flat lying orientations chemisorption occurs, with the final state corresponding to a bent CO 2 molecule with bond angles of 117-130 degrees and the elongation of the CO bond. For CO+O co-adsorption, the stable configurations corresponded to CO dipole moment orientations of 100-172 degrees with respect to the surface normal and the elongation of the CO bond. The most stable chemisorption cases correspond to anomalously large rumpling of the top Pu layer. The interactions of the CO 2 and CO with the Pu surface have been analyzed using the energy density of states and difference charge density distributions. The nature and the behavior of the 5f electrons have also been discussed in detail in the context of this study. (authors)

  1. Dissociation coefficients of protein adsorption to nanoparticles as quantitative metrics for description of the protein corona: A comparison of experimental techniques and methodological relevance

    KAUST Repository

    Hü hn, Jonas; Fedeli, Chiara; Zhang, Qian; Masood, Atif; del Pino, Pablo; Khashab, Niveen M.; Papini, Emanuele; Parak, Wolfgang J.

    2015-01-01

    Protein adsorption to nanoparticles is described as a chemical reaction in which proteins attach to binding sites on the nanoparticle surface. This process can be described with a dissociation coefficient, which tells how many proteins are adsorbed per nanoparticle in dependence of the protein concentration. Different techniques to experimentally determine dissociation coefficients of protein adsorption to nanoparticles are reviewed. Results of more than 130 experiments in which dissociation coefficients have been determined are compared. Data show that different methods, nanoparticle systems, and proteins can lead to significantly different dissociation coefficients. However, we observed a clear tendency of smaller dissociation coefficients upon less negative towards more positive zeta potentials of the nanoparticles. The zeta potential thus is a key parameter influencing protein adsorption to the surface of nanoparticles. Our analysis highlights the importance of the characterization of the parameters governing protein-nanoparticle interaction for quantitative evaluation and objective literature comparison.

  2. Dissociation coefficients of protein adsorption to nanoparticles as quantitative metrics for description of the protein corona: A comparison of experimental techniques and methodological relevance

    KAUST Repository

    Hühn, Jonas

    2015-12-31

    Protein adsorption to nanoparticles is described as a chemical reaction in which proteins attach to binding sites on the nanoparticle surface. This process can be described with a dissociation coefficient, which tells how many proteins are adsorbed per nanoparticle in dependence of the protein concentration. Different techniques to experimentally determine dissociation coefficients of protein adsorption to nanoparticles are reviewed. Results of more than 130 experiments in which dissociation coefficients have been determined are compared. Data show that different methods, nanoparticle systems, and proteins can lead to significantly different dissociation coefficients. However, we observed a clear tendency of smaller dissociation coefficients upon less negative towards more positive zeta potentials of the nanoparticles. The zeta potential thus is a key parameter influencing protein adsorption to the surface of nanoparticles. Our analysis highlights the importance of the characterization of the parameters governing protein-nanoparticle interaction for quantitative evaluation and objective literature comparison.

  3. Free energy landscape of dissociative adsorption of methane on ideal and defected graphene from ab initio simulations

    Science.gov (United States)

    Wlazło, M.; Majewski, J. A.

    2018-03-01

    We study the dissociative adsorption of methane at the surface of graphene. Free energy profiles, which include activation energies for different steps of the reaction, are computed from constrained ab initio molecular dynamics. At 300 K, the reaction barriers are much lower than experimental bond dissociation energies of gaseous methane, strongly indicating that the graphene surface acts as a catalyst of methane decomposition. On the other hand, the barriers are still much higher than on the nickel surface. Methane dissociation therefore occurs at a higher rate on nickel than on graphene. This reaction is a prerequisite for graphene growth from a precursor gas. Thus, the growth of the first monolayer should be a fast and efficient process while subsequent layers grow at a diminished rate and in a more controllable manner. Defects may also influence reaction energetics. This is evident from our results, in which simple defects (Stone-Wales defect and nitrogen substitution) lead to different free energy landscapes at both dissociation and adsorption steps of the process.

  4. The investigation of adsorption and dissociation of H2O on Li2O (111) by ab initio theory

    Science.gov (United States)

    Kong, Xianggang; Yu, You; Ma, Shenggui; Gao, Tao; Lu, Tiecheng; Xiao, Chengjian; Chen, Xiaojun; Zhang, Chuanyu

    2017-06-01

    The adsorption and dissociation mechanism of H2O molecule on the Li2O (111) surface have been systematically studied by using the density functional theory calculations. The parallel and vertical configurations of H2O at six different symmetry adsorption sites on the Li2O (111) surface are considered. In our calculations, it is suggested that H2O can dissociate on the perfect Li2O surface, of which the corresponding adsorption energy is 1.118 eV. And the adsorption energy decrease to be 0.241 eV when oxygen atom of H2O bonds to lithium atom of the slab. The final configurations are sensitive to the initial molecular orientation. By Bader charge analysis, the charge transfer from slab to adsorbed H2O/OH can be found due to the downward shift of lowest-unoccupied molecular orbital. We also analyze the vibrational frequencies at the Brillouin Zone centre for H2O molecule adsorbed on the stoichiometric surface. Due to the slightly different structure parameters, the calculated values of the vibrational frequencies of hydroxyl group range from 3824 to 3767 cm-1. Our results agree well with experimental results performed in FT-IR spectrum, which showed that an absorption peak of OH group appeared at 3677 cm-1 at room temperature.

  5. Doping efficiency of single and randomly stacked bilayer graphene by iodine adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Kim, HoKwon; Renault, Olivier; Rouchon, Denis; Mariolle, Denis; Chevalier, Nicolas [Univ. Grenoble Alpes, F-38000 Grenoble, France and CEA, LETI, MINATEC Campus, F-38054 Grenoble (France); Tyurnina, Anastasia; Simonato, Jean-Pierre; Dijon, Jean [Univ. Grenoble Alpes, F-38000 Grenoble, France and CEA, LITEN, Minatec Campus, F-38054 Grenoble (France)

    2014-07-07

    We report on the efficiency and thermal stability of p-doping by iodine on single and randomly stacked, weakly coupled bilayer polycrystalline graphene, as directly measured by photoelectron emission microscopy. The doping results in work function value increase of 0.4–0.5 eV, with a higher degree of iodine uptake by the bilayer (2%) as compared to the single layer (1%) suggesting iodine intercalation in the bilayer. The chemistry of iodine is identified accordingly as I{sub 3}{sup −} and I{sub 5}{sup −} poly iodide anionic complexes with slightly higher concentration of I{sub 5}{sup −} in bilayer than monolayer graphene, likely attributed to differences in doping mechanisms. Temperature dependent in-situ annealing of the doped films demonstrated that the doping remains efficient up to 200 °C.

  6. The investigation of adsorption and dissociation of H2O on Li2O (111) by ab initio theory

    International Nuclear Information System (INIS)

    Kong, Xianggang; Yu, You; Ma, Shenggui; Gao, Tao; Lu, Tiecheng; Xiao, Chengjian; Chen, Xiaojun; Zhang, Chuanyu

    2017-01-01

    Highlights: • The adsorption structures of H 2 O on Li 2 O (111) are obtained by calculations. • By Bader charge analysis, the charge translation from slab to adsorbate is found. • The vibrational frequencies of adsorbate are in line with the experimental values. - Abstract: The adsorption and dissociation mechanism of H 2 O molecule on the Li 2 O (111) surface have been systematically studied by using the density functional theory calculations. The parallel and vertical configurations of H 2 O at six different symmetry adsorption sites on the Li 2 O (111) surface are considered. In our calculations, it is suggested that H 2 O can dissociate on the perfect Li 2 O surface, of which the corresponding adsorption energy is 1.118 eV. And the adsorption energy decrease to be 0.241 eV when oxygen atom of H 2 O bonds to lithium atom of the slab. The final configurations are sensitive to the initial molecular orientation. By Bader charge analysis, the charge transfer from slab to adsorbed H 2 O/OH can be found due to the downward shift of lowest-unoccupied molecular orbital. We also analyze the vibrational frequencies at the Brillouin Zone centre for H 2 O molecule adsorbed on the stoichiometric surface. Due to the slightly different structure parameters, the calculated values of the vibrational frequencies of hydroxyl group range from 3824 to 3767 cm −1 . Our results agree well with experimental results performed in FT-IR spectrum, which showed that an absorption peak of OH group appeared at 3677 cm −1 at room temperature.

  7. The influence of physical parameters on the adsorption of iodine 131 by activated charcoals

    International Nuclear Information System (INIS)

    Billard, F.; Chevalier, G.; Caron, J.; Van Der Meersch, J.

    1966-01-01

    Following an outline of the means of generating iodine 131 in the gas phase and a brief description of the apparatus used, the authors analyse the experimental results obtained on the trapping of iodine 131 by activated charcoal. The efficiency depends concurrently on the relative humidity and the iodine concentration of the air. While it is independent of this concentration in dry air, it does not exceed 50 in moist air, whatever the bed depth, when the concentration is less than 1 mCi/m 3 , then it increases with the concentrations to reach values close to those obtained in dry air for concentrations of around 1000 Ci/m 3 . At the same time the efficiency of a dust filter with respect to iodine remains very low in dry air whatever the iodine concentration; in moist air this efficiency, which is high at low concentrations, decreases when the latter increases. In addition if a charcoal bed is divided into several beds, separated by an amount corresponding to a passage time of about a second, it is found that the efficiency of the whole is appreciably higher than that of the initial bed. These results appear to establish the existence of at least two forms of iodine, one molecular form and one particulate form probably formed by clusters, the forms equilibrium being functions of the relative concentrations of iodine and water vapour in the air. The third form evidence, a gaseous form compound, remains hypothetical; the experimental curves can be explained either by the molecular and particular forms reversibility or by the increase of clusters size with the relative humidity of the air. (authors) [fr

  8. Adsorption of malachite green and iodine on rice husk-based porous carbon

    International Nuclear Information System (INIS)

    Guo Yupeng; Zhang Hui; Tao Nannan; Liu Yanhua; Qi Juirui; Wang Zichen; Xu Hongding

    2003-01-01

    Adsorption isotherms of I 2 and malachite green (MG) by rice husk-based porous carbons (RHCs) from aqueous medium have been studied. Three samples of carbons prepared by NaOH-activation, three samples prepared by KOH-activation and two samples of commercial carbons have been studied. And the adsorption isotherms have been determined after modifying the carbon surfaces by oxidation with nitric acid and hydrogen peroxide and after degassing at 800 deg. C. The results have been found to follow the Freundlich adsorption isotherm. Three samples of N series have larger capacity for removing I 2 and MG from solution compared to that of the tested commercial carbons. The adsorption capacity of I 2 is similar for K series and commercial carbons. And the capacity of commercial carbons for MG is larger than K series. The adsorption capacity of I 2 on oxidation carbons has increased for hydrogen peroxide treatment and decreased for nitric acid, and that of MG is decreased. But the adsorption capacities of I 2 and MG increase on degassing. On the other hand, the adsorption of I 2 increases after modifying the carbon surfaces by HCl without oxidation. Suitable mechanisms have been proposed

  9. Adsorption and possible dissociation of glucose by the [BN fullerene-B6]- magnetic nanocomposite. In silico studies

    Science.gov (United States)

    Anota, E. Chigo; Villanueva, M. Salazar; Shakerzadeh, E.; Castro, M.

    2018-02-01

    The adsorption, activation and possible dissociation of the glucose molecule on the magnetic [BN fullerene-B6]- system is performed by means of density functional theory calculations. Three models of magnetic nanocomposites were inspected: i) pristine BN fullerene, BN fullerene functionalized with a magnetic B6 cluster which generates two structures: ii) pyramidal (P) and iii) triangular (T). Chemical interactions of glucose appear for all these cases; however, for the BNF:B6(T)—glucose system, the interaction generates an effect of dissociation on glucose, due to the magnetic effects, since it has high spin multiplicity. The latter nanocomposite shows electronic behavior like-conductor and like-semi-conductor for the P and T geometries, respectively. Intrinsic magnetism associated to values of 1.0 magneton bohr (µB) for the pyramidal and 5.0 µB for the triangular structure, high polarity, and low-chemical reactivity are found for these systems. These interesting properties make these functionalized fullerenes a good option for being used as nano-vehicles for drug delivery. These quantum descriptors remain invariant when the [BN]-fullerene and [BNF:B6 (P) or (T)]- nanocomposites are interacting with the glucose molecule. According to the determined adsorption energy, chemisorption regimes occur in both the phases: gas and aqueous medium.

  10. A first principle study for the adsorption and absorption of carbon atom and the CO dissociation on Ir(100) surface

    Energy Technology Data Exchange (ETDEWEB)

    Erikat, I. A., E-mail: ihsanas@yahoo.com [Department of Physics, Jerash University, Jerash-26150 (Jordan); Hamad, B. A. [Department of Physics, The University of Jordan, Amman-11942 (Jordan)

    2013-11-07

    We employ density functional theory to examine the adsorption and absorption of carbon atom as well as the dissociation of carbon monoxide on Ir(100) surface. We find that carbon atoms bind strongly with Ir(100) surface and prefer the high coordination hollow site for all coverages. In the case of 0.75 ML coverage of carbon, we obtain a bridging metal structure due to the balance between Ir–C and Ir–Ir interactions. In the subsurface region, the carbon atom prefers the octahedral site of Ir(100) surface. We find large diffusion barrier for carbon atom into Ir(100) surface (2.70 eV) due to the strong bonding between carbon atom and Ir(100) surface, whereas we find a very small segregation barrier (0.22 eV) from subsurface to the surface. The minimum energy path and energy barrier for the dissociation of CO on Ir(100) surface are obtained by using climbing image nudge elastic band. The energy barrier of CO dissociation on Ir(100) surface is found to be 3.01 eV, which is appreciably larger than the association energy (1.61 eV) of this molecule.

  11. A first principle study for the adsorption and absorption of carbon atom and the CO dissociation on Ir(100) surface

    Science.gov (United States)

    Erikat, I. A.; Hamad, B. A.

    2013-11-01

    We employ density functional theory to examine the adsorption and absorption of carbon atom as well as the dissociation of carbon monoxide on Ir(100) surface. We find that carbon atoms bind strongly with Ir(100) surface and prefer the high coordination hollow site for all coverages. In the case of 0.75 ML coverage of carbon, we obtain a bridging metal structure due to the balance between Ir-C and Ir-Ir interactions. In the subsurface region, the carbon atom prefers the octahedral site of Ir(100) surface. We find large diffusion barrier for carbon atom into Ir(100) surface (2.70 eV) due to the strong bonding between carbon atom and Ir(100) surface, whereas we find a very small segregation barrier (0.22 eV) from subsurface to the surface. The minimum energy path and energy barrier for the dissociation of CO on Ir(100) surface are obtained by using climbing image nudge elastic band. The energy barrier of CO dissociation on Ir(100) surface is found to be 3.01 eV, which is appreciably larger than the association energy (1.61 eV) of this molecule.

  12. A first principle study for the adsorption and absorption of carbon atom and the CO dissociation on Ir(100) surface

    International Nuclear Information System (INIS)

    Erikat, I. A.; Hamad, B. A.

    2013-01-01

    We employ density functional theory to examine the adsorption and absorption of carbon atom as well as the dissociation of carbon monoxide on Ir(100) surface. We find that carbon atoms bind strongly with Ir(100) surface and prefer the high coordination hollow site for all coverages. In the case of 0.75 ML coverage of carbon, we obtain a bridging metal structure due to the balance between Ir–C and Ir–Ir interactions. In the subsurface region, the carbon atom prefers the octahedral site of Ir(100) surface. We find large diffusion barrier for carbon atom into Ir(100) surface (2.70 eV) due to the strong bonding between carbon atom and Ir(100) surface, whereas we find a very small segregation barrier (0.22 eV) from subsurface to the surface. The minimum energy path and energy barrier for the dissociation of CO on Ir(100) surface are obtained by using climbing image nudge elastic band. The energy barrier of CO dissociation on Ir(100) surface is found to be 3.01 eV, which is appreciably larger than the association energy (1.61 eV) of this molecule

  13. Studies on the Mechanisms of Methyl Iodide Adsorption and Iodine Retention on Silver-Mordenite

    Energy Technology Data Exchange (ETDEWEB)

    Nenoff, Tina Maria [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Soelberg, Nick [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2014-09-01

    Silver-containing mordenite (MOR) is a longstanding benchmark for radioiodine capture, reacting with molecular iodine (I2) to form AgI. However the mechanisms for organoiodine capture are not well understood. Here we investigate the capture of methyl iodide from complex mixed gas streams by combining chemical analysis of the effluent gas stream with in depth characterization of the recovered sorbent.

  14. Adsorption of water on O(2x2)/Ru(0001): thermal stability and inhibition of dissociation by H2O-O bonding

    Energy Technology Data Exchange (ETDEWEB)

    Mugarza, Aitor; Shimizu, Tomoko; Cabrera-Sanfelix, Pepa; Sanchez-Portal, Daniel; Arnau, Andres; Salmeron, Miquel

    2008-08-01

    The effect of preadsorbed oxygen on the subsequent adsorption and reactions of water on Ru(0001) has been studied using low temperature scanning tunneling microscopy and DFT calculations. Experiments were carried out for O coverages close to 0.25 ML. It was found that no dissociation of water takes place up to the desorption temperature of {approx}180-230 K. DFT calculations show that intact water on O(2x2)/Ru(0001) is {approx} 0.49 eV more stable than the dissociation products, H and OH, at their preferred fcc and top adsorption sites.

  15. ReaxFF Grand Canonical Monte Carlo simulation of adsorption and dissociation of oxygen on platinum (111)

    Science.gov (United States)

    Valentini, Paolo; Schwartzentruber, Thomas E.; Cozmuta, Ioana

    2011-12-01

    Atomic-level Grand Canonical Monte Carlo (GCMC) simulations equipped with a reactive force field (ReaxFF) are used to study atomic oxygen adsorption on a Pt(111) surface. The off-lattice GCMC calculations presented here rely solely on the interatomic potential and do not necessitate the pre-computation of surface adlayer structures and their interpolation. As such, they provide a predictive description of adsorbate phases. In this study, validation is obtained with experimental evidence (steric heats of adsorption and isotherms) as well as DFT-based state diagrams available in the literature. The ReaxFF computed steric heats of adsorption agree well with experimental data, and this study clearly shows that indirect dissociative adsorption of O2 on Pt(111) is an activated process at non-zero coverages, with an activation energy that monotonically increases with coverage. At a coverage of 0.25 ML, a highly ordered p(2 × 2) adlayer is found, in agreement with several low-energy electron diffraction observations. Isotherms obtained from the GCMC simulations compare qualitatively and quantitatively well with previous DFT-based state diagrams, but are in disagreement with the experimental data sets available. ReaxFF GCMC simulations at very high coverages show that O atoms prefer to bind in fcc hollow sites, at least up to 0.8 ML considered in the present work. At moderate coverages, little to no disorder appears in the Pt lattice. At high coverages, some Pt atoms markedly protrude out of the surface plane. This observation is in qualitative agreement with recent STM images of an oxygen covered Pt surface. The use of the GCMC technique based on a transferable potential is particularly valuable to produce more realistic systems (adsorbent and adsorbate) to be used in subsequent dynamical simulations (Molecular Dynamics) to address recombination reactions (via either Eley-Rideal or Langmuir-Hinshelwood mechanisms) on variously covered surfaces. By using GCMC and Molecular

  16. Association/dissociation in dense gases and adsorption/desorption on surfaces

    International Nuclear Information System (INIS)

    Flannery, M.R.

    1984-01-01

    A new comprehensive theory is described for the time evolution towards equilibrium of association and dissociation in a dense gas. Expressions are formulated and are illustrated for the net probabilities of association to stable vibrational levels and dissociation to the continuum from an arbitrary bound vibrational level via collision with the thermal gas bath. A general variational principle emerges: The rate which corresponds to the overall direction of the process always adjusts itself to a minimum and the time evolution towards equilibrium is hindered. Analogy is established with Kirchhoff's Laws and Tellegen's Theorem for electrical networks, and with the Principle of Least Dissipation basic to thermodynamics, heat conduction, and fluid mechanics. The theory can also be modified to provide the first basic microscopic account of Associative Desorption of atoms from and Dissociative Chemisorption of molecules to surfaces

  17. Comparison of reactivity on step and terrace sites of Pd (3 3 2) surface for the dissociative adsorption of hydrogen: A quantum chemical molecular dynamics study

    International Nuclear Information System (INIS)

    Ahmed, Farouq; Nagumo, Ryo; Miura, Ryuji; Ai, Suzuki; Tsuboi, Hideyuki; Hatakeyama, Nozomu; Endou, Akira; Takaba, Hiromitsu; Kubo, Momoji; Miyamoto, Akira

    2011-01-01

    The notion of 'active sites' is fundamental to heterogeneous catalysis. However, the exact nature of the active sites, and hence the mechanism by which they act, are still largely a matter of speculation. In this study, we have presented a systematic quantum chemical molecular dynamics (QCMD) calculations for the interaction of hydrogen on different step and terrace sites of the Pd (3 3 2) surface. Finally the dissociative adsorption of hydrogen on step and terrace as well as the influence of surface hydrogen vacancy for the dissociative adsorption of hydrogen has been investigated through QCMD. This is a state-of-the-art method for calculating the interaction of atoms and molecules with metal surfaces. It is found that fully hydrogen covered (saturated) step sites can dissociate hydrogen moderately and that a monovacancy surface is suitable for significant dissociative adsorption of hydrogen. However in terrace site of the surface we have found that dissociation of hydrogen takes place only on Pd sites where the metal atom is not bound to any pre-adsorbed hydrogen atoms. Furthermore, from the molecular dynamics and electronic structure calculations, we identify a number of consequences for the interpretation and modeling of diffusion experiments demonstrating the coverage and directional dependence of atomic hydrogen diffusion on stepped palladium surface.

  18. SFG study of methanol dissociative adsorption at Pt(1 0 0), Pt(1 1 0) and Pt(1 1 1) electrodes surfaces

    Science.gov (United States)

    Vidal, F.; Busson, B.; Six, C.; Pluchery, O.; Tadjeddine, A.

    2002-04-01

    The Pt( hkl)/methanol in acidic solution interface which constitutes a model of the anodic part of a fuel cell is studied by infrared-visible sum frequency generation vibrational spectroscopy. Methanol dissociative adsorption leads to CO poisoning of the Pt electrode surfaces. The structure of the CO/Pt( hkl) interface depends strongly on the orientation of the surface electrode.

  19. Improving COIL Efficiency By Iodine Pre-Dissociation Via Corona Discharge In The Transonic Section Of The Secondary Flow

    National Research Council Canada - National Science Library

    Rosenwaks, Zamik; Barmashenko, Boris

    2006-01-01

    ...: We intend to carry out a comprehensive experimental study of I2 pre-dissociation, based on applying corona discharge in the transonic section of the secondary flow in the COIL supersonic nozzle...

  20. Oxygen adsorption and dissociation during the oxidation of monolayer Ti2C

    KAUST Repository

    Gan, Liyong

    2013-08-20

    Exfoliated two-dimensional early transition metal carbides and carbonitrides are usually not terminated by metal atoms but saturated by O, OH, and/or F, thus making it difficult to understand the surface structure evolution and the induced electronic modifications. To fill this gap, density functional theory and molecular dynamics simulations are performed to capture the initial stage of the oxidation process of Ti2C, a prototypical example from the recently fabricated class of two-dimensional carbides and carbonitrides. It is shown that the unsaturated Ti 3d orbitals of the pristine Ti2C surface interact strongly with the approaching O2 molecules, resulting in barrierless O2 dissociation. The diffusion of the dissociated O atoms is also found to be very facile. Molecular dynamics simulations suggest that both dissociation and diffusion are enhanced as the O2 coverage increases to 0.25 monolayer. For a coverage of less than 0.11 monolayer, the adsorbates lead to a minor modification of the electronic properties of Ti2C, while the modification is remarkable at 0.25 monolayer. The formed Ti2CO2 after O saturation is an indirect narrow gap semiconductor (0.33 eV) with high intrinsic carrier concentration at room temperature and high thermodynamic stability at intermediate temperature (e.g., 550 °C).

  1. Oxygen adsorption and dissociation during the oxidation of monolayer Ti2C

    KAUST Repository

    Gan, Liyong; Huang, Dan; Schwingenschlö gl, Udo

    2013-01-01

    Exfoliated two-dimensional early transition metal carbides and carbonitrides are usually not terminated by metal atoms but saturated by O, OH, and/or F, thus making it difficult to understand the surface structure evolution and the induced electronic modifications. To fill this gap, density functional theory and molecular dynamics simulations are performed to capture the initial stage of the oxidation process of Ti2C, a prototypical example from the recently fabricated class of two-dimensional carbides and carbonitrides. It is shown that the unsaturated Ti 3d orbitals of the pristine Ti2C surface interact strongly with the approaching O2 molecules, resulting in barrierless O2 dissociation. The diffusion of the dissociated O atoms is also found to be very facile. Molecular dynamics simulations suggest that both dissociation and diffusion are enhanced as the O2 coverage increases to 0.25 monolayer. For a coverage of less than 0.11 monolayer, the adsorbates lead to a minor modification of the electronic properties of Ti2C, while the modification is remarkable at 0.25 monolayer. The formed Ti2CO2 after O saturation is an indirect narrow gap semiconductor (0.33 eV) with high intrinsic carrier concentration at room temperature and high thermodynamic stability at intermediate temperature (e.g., 550 °C).

  2. Theoretical Investigation of Hydrogen Adsorption and Dissociation on Iron and Iron Carbide Surfaces Using the ReaxFF Reactive Force Field Method

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Chenyu; van Duin, Adri C.T.; Sorescu, Dan C.

    2012-06-01

    We have developed a ReaxFF reactive force field to describe hydrogen adsorption and dissociation on iron and iron carbide surfaces relevant for simulation of Fischer–Tropsch (FT) synthesis on iron catalysts. This force field enables large system (>>1000 atoms) simulations of hydrogen related reactions with iron. The ReaxFF force field parameters are trained against a substantial amount of structural and energetic data including the equations of state and heats of formation of iron and iron carbide related materials, as well as hydrogen interaction with iron surfaces and different phases of bulk iron. We have validated the accuracy and applicability of ReaxFF force field by carrying out molecular dynamics simulations of hydrogen adsorption, dissociation and recombination on iron and iron carbide surfaces. The barriers and reaction energies for molecular dissociation on these two types of surfaces have been compared and the effect of subsurface carbon on hydrogen interaction with iron surface is evaluated. We found that existence of carbon atoms at subsurface iron sites tends to increase the hydrogen dissociation energy barrier on the surface, and also makes the corresponding hydrogen dissociative state relatively more stable compared to that on bare iron. These properties of iron carbide will affect the dissociation rate of H{sub 2} and will retain more surface hydride species, thus influencing the dynamics of the FT synthesis process.

  3. On the nature of gallium species in gallium-modified mordenite and MFI zeolites. A comparative DRIFT study of carbon monoxide adsorption and hydrogen dissociation.

    Science.gov (United States)

    Serykh, Alexander I; Kolesnikov, Stanislav P

    2011-04-21

    The results of a DRIFT study of carbon monoxide molecular adsorption and hydrogen dissociative adsorption on gallium-modified mordenite and MFI (ZSM-5) zeolites are presented. It was found that in the reduced gallium-modified mordenite (Ga-MOR) both Ga(3+) and Ga(+) exchanged cations are present and can be detected by CO adsorption. Ga(3+) cations in Ga-MOR dissociatively adsorb molecular hydrogen at elevated temperatures, resulting in the formation of gallium hydride species and acidic hydroxyl groups. In the reduced Ga-MFI evacuated at 823 K under medium vacuum conditions only Ga(+) exchanged intrazeolite cations were detected. It was found, however, that Ga(3+) intrazeolite exchanged cations which form upon high-temperature disproportionation of Ga(+) cations in the reduced Ga-MFI and Ga-MOR can be stabilized by high-temperature oxidation of these zeolites.

  4. A computational study on the energetics and mechanisms for the dissociative adsorption of SiHx(x = 1-4) on W(1 1 1) surface

    Science.gov (United States)

    Lin, Y. H.; Raghunath, P.; Lin, M. C.

    2016-01-01

    The adsorption and dissociation mechanisms of SiHx(x = 1-4) species on W(1 1 1) surface have been investigated by using the periodic density functional theory with the projector-augmented wave approach. The adsorption of all the species on four surface sites: top (T), bridge (B), shallow (S), and deep (D) sites have been analyzed. For SiH4 on a top site, T-SiH4(a), it is more stable with an adsorption energy of 2.6 kcal/mol. For SiH3, the 3-fold shallow site is most favorable with adsorption energy of 46.0 kcal/mol. For SiH2, its adsorption on a bridge site is most stable with 73.0 kcal/mol binding energy, whereas for SiH and Si the most stable adsorption configurations are on 3-fold deep sites with very high adsorption energies, 111.8 and 134.7 kcal/mol, respectively. The potential energy surfaces for the dissociative adsorption of all SiHx species on the W(1 1 1) surface have been constructed using the CINEB method. The barriers for H-atom migration from SiHx(a) to its neighboring W atoms, preferentially on B-sites, were predicted to be 0.4, 1.0, 4.5 and, 8.0 kcal/mol, respectively, for x = 4, 3, 2, and 1, respectively. The adsorption energy of the H atom on a bridge site on the clean W(1 1 1) surface was predicted to be 65.9 kcal/mol, which was found to be slightly affected by the co-adsorption of SiHx-1 within ± 1 kcal/mol.

  5. Direct Visualization of 2-Butanol Adsorption and Dissociation on TiO2(110)

    International Nuclear Information System (INIS)

    Zhang, Zhenrong; Bondarchuk, Olexsandr; Kay, Bruce D.; White, J. M.; Dohnalek, Zdenek

    2007-01-01

    Atomically resolved scanning tunneling microscopy (STM) images of identical regions of a TiO2(110) surface were gathered before and after controlled doses of 2-butanol (CH3CH2CH(OH)CH3) at ambient temperature (∼300 K). When dosing is initiated, 2-butanol preferentially adsorbs at bridge-bonded oxygen vacancy (BBOv) sites and dissociates via O-H, not C-O, bond scission to form paired 2-butoxy and hydroxyl species evidenced by two local maxima in STM line profiles. The measured separation is 0.4 nm, slightly larger than the measured separation (0.3 nm) between neighboring bridge-bonded oxygen anions in the surface unit cell of TiO2(110). As the dose increases, but before all the BBOv are occupied, there is direct STM evidence of hydroxyl proton hopping to an adjacent oxygen anion row. This process is facilitated by species bound to 5-coordinate Ti4+ rows, presumably undissociated 2-butanol, that hop slowly compared the STM imaging time scale. The backbones of these mobile species are centered over the Ti4+ rows with preference for lying parallel to these rows. On the other hand, the carbon backbones of the 2-butoxy species that fill BBOv's are centered over the O2- rows and prefer an orientation perpendicular to these rows. As the oxygen vacancy concentration increases from 0.4 to 11% and 2-butanol is dosed the ratio of mobile species to 2-butoxy species decreases for doses that do not fill all the BBOv

  6. Elementary Steps of Syngas Reactions on Mo2C(001): Adsorption Thermochemistry and Bond Dissociation

    Energy Technology Data Exchange (ETDEWEB)

    Medford, Andrew

    2012-02-16

    Density functional theory (DFT) and ab initio thermodynamics are applied in order to investigate the most stable surface and subsurface terminations of Mo{sub 2}C(001) as a function of chemical potential and in the presence of syngas. The Mo-terminated (001) surface is then used as a model surface to evaluate the thermochemistry and energetic barriers for key elementary steps in syngas reactions. Adsorption energy scaling relations and Broensted-Evans-Polanyi relationships are established and used to place Mo{sub 2}C into the context of transition metal surfaces. The results indicate that the surface termination is a complex function of reaction conditions and kinetics. It is predicted that the surface will be covered by either C{sub 2}H{sub 2} or O depending on conditions. Comparisons to transition metals indicate that the Mo-terminated Mo{sub 2}C(001) surface exhibits carbon reactivity similar to transition metals such as Ru and Ir, but is significantly more reactive towards oxygen.

  7. Density functional theory study of the adsorption and dissociation of O{sub 2} on CuO(1 1 1) surface

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Shujuan, E-mail: sunshujuan@hebut.edu.cn [School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300130 (China); Li, Chunyu [Science and Technology Innovation Center, Datang Technologies Industry Group Company Limited, Beijing (China); Zhang, Dongsheng [School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300130 (China); Wang, Yanji, E-mail: yjwang@hebut.edu.cn [School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300130 (China)

    2015-04-01

    Highlights: • The dissociation mechanisms of O{sub 2} on the CuO(1 1 1) surface have been obtained. • The energy barriers and reaction energies are calculated. • The presence of oxygen vacancy can obviously improve the catalytic activity of CuO. - Abstract: Density functional theory (DFT) have been performed to investigate the adsorption and dissociation of O{sub 2} on the perfect and oxygen-deficient CuO(1 1 1) surfaces. The calculated results indicate that the bridge site of two Cu{sub sub} atoms is the most favorable site for O adsorption on the perfect CuO(1 1 1) surface. But on the oxygen-deficient CuO(1 1 1) surface, the O atom adsorbed on O{sub vacancy} site after optimization. On the perfect and oxygen-deficient CuO(1 1 1) surfaces, the O{sub 2} are all paralleling to the surface after optimization. Possible dissociation pathways of molecularly adsorbed O{sub 2} on the two surfaces are identified. The calculated results suggest that the presence of oxygen vacancy exhibits a strong chemical reactivity towards the dissociation of O{sub 2} and can obviously improve the catalytic activity of CuO.

  8. First-principles investigation of methanethiol adsorption and dissociation mechanisms on the high-Miller-index vicinal surface Cu(4 1 0)

    International Nuclear Information System (INIS)

    Raouafi, Faycal; Lassoued, Karima; Seydou, Mahamadou; Taleb, Abdelhafed; Diawara, Boubakar

    2016-01-01

    In this work, we present detailed investigations of methanethiol adsorption on a Cu(4 1 0) surface within the framework of the self-consistent first-principles calculations as implemented in the Vienna ab initio simulation package (VASP). In particular, the adsorption sites, the surface coverage rate and electronic properties have been determined and compared to experimental values. The results indicate that the favorable adsorption site in the case of low coverage rate is a bridge on the step followed by the hollow site on the terrace. The adsorption significantly affects the outermost layer of the surface mainly for a higher coverage rate in a (2  ×  2) supercell. The nature of the chemisorption process on the surface is analyzed by means of the density of states which, combined with charge density difference and atomic charge calculations, confirms the ionic character of the S–Cu bond. The specific effect of the presence of steps is highlighted by comparing the adsorption on the (1 0 0) terrace to the adsorption on the extended Cu(1 0 0) surface. Compared to the flat Cu(1 0 0), it is found here that while the stability is almost the same at p(2  ×  2) coverage, the CH 3 S/Cu(4 1 0) becomes more stable than CH 3 S/Cu(1 0 0) at c(2  ×  2) coverage with 0.30 eV per molecule. The mechanism of methanethiol dissociation is explored by the nudged elastic band method and demonstrates that the most favorable path is dissociation followed by migration of hydrogen from the step to its most stable position (hollow on the terrace) with energy barriers less than 0.5 eV. (paper)

  9. Adsorption and dissociation of H{sub 2}S on Mo{sub 2}C(001) surface-A first-principle study

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Dianling; Guo, Wenyue, E-mail: wyguo@upc.edu.cn; Liu, Yunjie; Chi, Yuhua

    2015-10-01

    Highlights: • Adsorption of reactants, intermediates involved was investigated. • The Mulliken charge and partial density of states were analyzed. • The dissociation mechanism was investigated. • The optimal pathway for the dissociation of H{sub 2}S on the Mo{sub 2}C(001) surface was given. - Abstract: The adsorption and decomposition reaction mechanisms of H{sub 2}S on Mo{sub 2}C(001) has been systematically studied using self-consistent periodic density functional theory. Results show that the molecular of H{sub 2}S is adsorbed either on the Mo top site or bridge site. Mulliken population analysis and density of states for H{sub 2}S/Mo-terminated Mo{sub 2}C(001) adsorption system are examined to confirm the adsorption mechanism of H{sub 2}S with the Mo{sub 2}C(001) surface, which can involve the donation of charge from the “s lone pair electrons” that are LUMO orbitals into the surface and the back donation of electrons from the surface into the HOMO orbital. The optimal pathway for the dissociation of H{sub 2}S on the Mo{sub 2}C(001) surface can be H{sub 2}S{sub top} → SH{sub fcc} + H{sub fcc} → S{sub fcc} + H{sub fcc} + H{sub fcc}. The first step is the rate-determining step because it has the smallest rate constant among the possible reactions pathways.

  10. The investigation of adsorption and dissociation of H{sub 2}O on Li{sub 2}O (111) by ab initio theory

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Xianggang [Institute of Atom and Molecular physics, Sichuan University, Chengdu, 610065 (China); Yu, You [College of Optoelectronic Technology, Chengdu University of Information Technology, Chengdu, 610225 (China); Ma, Shenggui [Institute of Atom and Molecular physics, Sichuan University, Chengdu, 610065 (China); Gao, Tao, E-mail: gaotao@scu.edu.cn [Institute of Atom and Molecular physics, Sichuan University, Chengdu, 610065 (China); Lu, Tiecheng [Department of Physics and Key Laboratory for Radiation Physics & Technology of Ministry of Education, Sichuan University, Chengdu, 610065 (China); Xiao, Chengjian; Chen, Xiaojun [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, 621900 (China); Zhang, Chuanyu [College of Geophysics, Chengdu University of Technology, Chengdu, 610059 (China)

    2017-06-15

    Highlights: • The adsorption structures of H{sub 2}O on Li{sub 2}O (111) are obtained by calculations. • By Bader charge analysis, the charge translation from slab to adsorbate is found. • The vibrational frequencies of adsorbate are in line with the experimental values. - Abstract: The adsorption and dissociation mechanism of H{sub 2}O molecule on the Li{sub 2}O (111) surface have been systematically studied by using the density functional theory calculations. The parallel and vertical configurations of H{sub 2}O at six different symmetry adsorption sites on the Li{sub 2}O (111) surface are considered. In our calculations, it is suggested that H{sub 2}O can dissociate on the perfect Li{sub 2}O surface, of which the corresponding adsorption energy is 1.118 eV. And the adsorption energy decrease to be 0.241 eV when oxygen atom of H{sub 2}O bonds to lithium atom of the slab. The final configurations are sensitive to the initial molecular orientation. By Bader charge analysis, the charge transfer from slab to adsorbed H{sub 2}O/OH can be found due to the downward shift of lowest-unoccupied molecular orbital. We also analyze the vibrational frequencies at the Brillouin Zone centre for H{sub 2}O molecule adsorbed on the stoichiometric surface. Due to the slightly different structure parameters, the calculated values of the vibrational frequencies of hydroxyl group range from 3824 to 3767 cm{sup −1}. Our results agree well with experimental results performed in FT-IR spectrum, which showed that an absorption peak of OH group appeared at 3677 cm{sup −1} at room temperature.

  11. Adsorption and dissociation of sulfur-based toxic gas molecules on silicene nanoribbons: a quest for high-performance gas sensors and catalysts.

    Science.gov (United States)

    Walia, Gurleen Kaur; Randhawa, Deep Kamal Kaur

    2018-03-16

    The adsorption behavior of sulfur-based toxic gases (H 2 S and SO 2 ) on armchair silicene nanoribbons (ASiNRs) was investigated using first-principles density functional theory (DFT). Being a zero band gap material, application of bulk silicene is limited in nanoelectronics, despite its high carrier mobility. By restricting its dimensions into one dimension, construction of nanoribbons, and by introduction of a defect, its band gap can be tuned. Pristine armchair silicene nanoribbons (P-ASiNRs) have a very low sensitivity to gas molecules. Therefore, a defect was introduced by removal of one Si atom, leading to increased sensitivity. To deeply understand the impact of the aforementioned gases on silicene nanoribbons, electronic band structures, density of states, charge transfers, adsorption energies, electron densities, current-voltage characteristics and most stable adsorption configurations were calculated. H 2 S is dissociated completely into HS and H species when adsorbed onto defective armchair silicene nanoribbons (D-ASiNRs). Thus, D-ASiNR is a likely catalyst for dissociation of the H 2 S gas molecule. Conversely, upon SO 2 adsorption, P-ASiNR acts as a suitable sensor, whereas D-ASiNR provides enhanced sensitivity compared with P-ASiNR. On the basis of these results, D-ASiNR can be expected to be a disposable sensor for SO 2 detection as well as a catalyst for H 2 S reduction. Graphical abstract Comparison of I-V characteristics of pristine and defective armchair silicene nanoribbons with H 2 S and SO 2 adsorbed on them.

  12. Dissociative adsorption of environment-friendly insulating medium C3F7CN on Cu(111) and Al(111) surface: A theoretical evaluation

    Science.gov (United States)

    Zhang, Xiaoxing; Li, Yi; Chen, Dachang; Xiao, Song; Tian, Shuangshuang; Tang, Ju; Wang, Dibo

    2018-03-01

    SF6 is extensively used in electrical applications because of its excellent insulation and arc extinguishing performance, but its strong greenhouse effect has negative impact on the atmosphere. The excellent performance of C3F7CN in greenhouse effect, insulation ability, safety, and thermal stability has been demonstrated, indicating that this compound can replace SF6 in electrical applications. However, little information is available on the compatibility of C3F7CN with metals, such as copper and aluminum, in devices. Material compatibility between new gas mixtures and materials used in Gas Insulated Switchgear (GIS) should be investigated to determine the long-term behavior of materials. In this paper, dissociative adsorption of C3F7CN on Cu (1 1 1) and Al (1 1 1) surfaces were analyzed based on density functional theory. Adsorption energy, charge transfer, density of states, and electron density difference of interaction between C3F7CN and two metals were analyzed. It was found that the adsorption energy of C3F7CN adsorbed on Cu (1 1 1) and Al (1 1 1) is both below 0.8 eV. This value indicates that the interaction between them is not very strong. In addition, the dissociation reaction path of gas molecules after adsorption requires certain activation energy. Therefore, C3F7CN and copper or aluminum have certain compatibility and the compatibility of C3F7CN with aluminum is better than that of copper. Related results provide a reference for predicting the aging mechanism of equipment and the selection or modification of major materials for equipment.

  13. Theoretical insights into the effect of terrace width and step edge coverage on CO adsorption and dissociation over stepped Ni surfaces.

    Science.gov (United States)

    Yang, Kuiwei; Zhang, Minhua; Yu, Yingzhe

    2017-07-21

    Vicinal surfaces of Ni are model catalysts of general interest and great importance in computational catalysis. Here we report a comprehensive study conducted with density functional theory on Ni[n(111) × (100)] (n = 2, 3 and 4) surfaces to explore the effect of terrace width and step edge coverage on CO adsorption and dissociation, a probe reaction relevant to many industrial processes. The coordination numbers (CN), the generalized coordination numbers and the d band partial density of states (d-PDOS) of Ni are identified as descriptors to faithfully reflect the difference of the step edge region for Ni[n(111) × (100)]. Based on analysis of the energy diagrams for CO activation and dissociation as well as the structural features of the Ni(311), Ni(211) and Ni(533) surfaces, Ni(211) (n = 3) is proposed as a model of adequate representativeness for Ni[n(111) × (100)] (n≥ 3) surface groups in investigating small molecule activation over such stepped structures. Further, a series of Ni(211) surfaces with the step edge coverage ranging from 1/4 to 1 monolayer (ML) were utilized to assess their effect on CO activation. The results show that CO adsorption is not sensitive to the step edge coverage, which could readily approach 1 ML under a CO-rich atmosphere. In contrast, CO dissociation manifests strong coverage dependence when the coverage exceeds 1/2 ML, indicating that significant adsorbate-adsorbate interactions emerge. These results are conducive to theoretical studies of metal-catalyzed surface processes where the defects play a vital role.

  14. Adsorption

    Directory of Open Access Journals (Sweden)

    Sushmita Banerjee

    2017-05-01

    Full Text Available Application of saw dust for the removal of an anionic dye, tartrazine, from aqueous solutions has been investigated. The experiments were carried out in batch mode. Effect of the parameters such as pH, initial dye concentration and temperature on the removal of the dye was studied. Equilibrium was achieved in 70 min. Maximum adsorption of dye was achieved at pH 3. Removal percent was found to be dependent on the initial concentration of dye solution, and maximum removal was found to be 97% at 1 mg/L of tartrazine. The removal increases from 71% to 97% when the initial concentration of dye solution decreases from 15 mg/L to 1 mg/L. The equilibrium adsorption data were analyzed by Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherm models. The (Langmuir adsorption capacity of the adsorbent is found to be 4.71 mg/g at 318 K. Kinetic modeling of the process of removal was carried out and the process of removal was found to follow a pseudo second order model and the value of rate constant for adsorption process was calculated as 2.7 × 10−3 g mg−1 min−1 at 318 K. The thermodynamic parameters such as change in free energy (ΔG°, enthalpy (ΔH° and entropy (ΔS° were determined and the negative values of ΔG° indicated that the process of removal was spontaneous at all values of temperatures. Further, the values of ΔH° indicated the endothermic nature of the process of removal.

  15. D2 dissociative adsorption on and associative desorption from Si(100): Dynamic consequences of an ab initio potential energy surface

    DEFF Research Database (Denmark)

    Luntz, A. C.; Kratzer, Peter

    1996-01-01

    favors the symmetric one. Under the conditions of many experiments, either could dominate. The calculations show quite weak dynamic coupling to the Si lattice for both paths, i.e., weak surface temperature dependences to dissociation and small energy loss to the lattice upon desorption......Dynamical calculations are reported for D-2 dissociative chemisorption on and associative desorption from a Si(100) surface. These calculations use the dynamically relevant effective potential which is based on an ab initio potential energy surface for the ''pre-paired'' species. Three coordinates...

  16. Surface species formed by the adsorption and dissociation of water molecules on Ru(0001) surface containing a small coverage of carbon atoms studied by scanning tunneling microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Dept of Materials Science and Engineering UCB; Dept of Applied Science and Technology, UCB; Institut de Ciencia de Materials de Barcelona, Barcelona, Spain; Instituto de Ciencia de Materiales de Madrid, Madrid, Spain; Department of Mechanical Engineering, Yale University; Salmeron, Miquel; Shimizu, Tomoko K.; Mugarza, Aitor; Cerda, Jorge I.; Heyde, Markus; Qi, Yabing; Schwarz, Udo D.; Ogletree, D. Frank; Salmeron, Miquel

    2008-04-26

    The adsorption and dissociation of water on a Ru(0001) surface containing a small amount ({le} 3 %) of carbon impurities was studied by scanning tunneling microscopy (STM). Various surface species are formed depending on the temperature. These include molecular H{sub 2}O, H{sub 2}O-C complexes, H, O, OH and CH. Clusters of either pure H{sub 2}O or mixed H{sub 2}O-OH species are also formed. Each of these species produces a characteristic contrast in the STM images and can be identified by experiment and by ab initio total energy calculations coupled with STM image simulations. Manipulation of individual species via excitation of vibrational modes with the tunneling electrons has been used as supporting evidence.

  17. Electrochemistry of iodine

    Energy Technology Data Exchange (ETDEWEB)

    Yaraliev, Ya.A. (AN Azerbajdzhanskoj SSR, Baku. Inst. Neorganicheskoj i Fizicheskoj Khimii)

    1982-06-01

    The review is devoted to investigations into oxidation-reduction processes in different systems including iodine. The data on adsorption of iodine on metals are discussed; the connection between the nature of iodine adsorption and the mechanism of its electrode reactions is considered. The metals studied can be placed in the following series taking into account the degree of I sorption on them: Cd approximately Tl < Sn approximately Pb < Ga < Bi < Hg < Co approximately Ni < Fe < Ag approximately Rh approximately Pd approximately Ir < Pt. The data are given of standard and equilibrium potentials in iodine systems. Electric oxidation and electric reduction of iodide ions is investigated using the methods of Faraday impedance and rectification, methods of voltamperometry and oscillopolarography, rotating disc electrode, chronopotentiometry. Anode and cathode processes of oxidation-reduction reactions in I/sup -//IO/sub 3//sup -/, I/sub 2//IO/sub 3//sup -/ and I/sub 2//I/sup +/ systems are analyzed.

  18. Adsorption properties of biologically active derivatives of quaternary ammonium surfactants and their mixtures at aqueous/air interface II. Dynamics of adsorption, micelles dissociation and cytotoxicity of QDLS.

    Science.gov (United States)

    Rojewska, Monika; Prochaska, Krystyna; Olejnik, Anna; Rychlik, Joanna

    2014-07-01

    The main aim of our study was analysis of adsorption dynamics of mixtures containing quaternary derivatives of lysosomotropic substance (QDLS). Two types of equimolar mixtures were considered: the ones containing two derivatives of lysosomotropic substances (DMALM-12 and DMGM-12) as well as the catanionic mixtures i.e. the systems containing QDLS and DBSNa. Dynamic surface tension measurements of surfactant mixtures were made. The results suggested that the diffusivity of the mixed system could be treated as the average value of rates of diffusion of individual components, micelles and ion pairs, which are present in the mixtures studied. Moreover, an attempt was made to explain the influence of the presence of micelles in the mixtures on their adsorption dynamics. The compounds examined show interesting biological properties which can be useful, especially for drug delivery in medical treatment. In vitro cytotoxic activities of the mixtures studied towards human cancer cells were evaluated. Most of the mixtures showed a high antiproliferative potential, especially the ones containing DMALM-12. Each cancer cell line used demonstrated different sensitivity to the same dose of the mixtures tested. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Technetium, Iodine, and Chromium Adsorption/Desorption Kd Values for Vadose Zone Pore Water, ILAW Glass, and Cast Stone Leachates Contacting an IDF Sand Sequence

    Energy Technology Data Exchange (ETDEWEB)

    Last, George V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Snyder, Michelle M.V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Um, Wooyong [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stephenson, John R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Leavy, Ian I. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Strickland, Christopher E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Bacon, Diana H. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Qafoku, Nikolla [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Serne, R. Jeffrey [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-11-01

    Performance and risk assessments of immobilized low-activity waste (ILAW) at the Integrated Disposal Facility (IDF) have shown that risks to groundwater are quite sensitive to adsorption-desorption interactions occurring in the near- and far-field environment. These interactions between the underlying sediments and the contaminants present in the leachates that descend from the buried glass, secondary waste grouts, and potentially Cast Stone low-activity waste packages have been represented in these assessments using the contaminant distribution coefficient (Kd) construct. Some contaminants (99Tc, 129I, and Cr) present in significant quantities in these wastes have low Kd values and tend to drive risk to public health and the environment. Relatively small changes in the Kd value can cause relatively large changes in the retardation factor. Thus, even relatively small uncertainty in the Kd value can result in a relatively large uncertainty in the risk determined through performance assessment modeling. The purpose of this study is to further reduce the uncertainty in Kd values for 99Tc, iodine (iodide and iodate), and Cr (chromate; CrO42-) by conducting systematic adsorption-desorption experiments using actual sand-dominated Hanford formation sediments from beneath the IDF and solutions that closely mimic Hanford vadose zone pore water and leachates from Cast Stone and ILAW glass waste forms. Twenty-four batch and 21 flow-through column experiments were conducted, yielding 261 Kd measurements for these key contaminants, and contributing to our understanding for predicting transport from wastes disposed to the IDF. While the batch Kd methodology is not well-suited for measuring Kd values for non-sorbing species (as noted by the U.S. Environmental Protection Agency), the batch Kd results presented here are not wholly inconsistent with the column Kd results, and could be used for sensitivity purposes. Results from the column experiments are consistent with the best

  20. Fast MAS 1H NMR Study of Water Adsorption and Dissociation on the (100) Surface of Ceria Nanocubes: A Fully Hydroxylated, Hydrophobic Ceria Surface

    Energy Technology Data Exchange (ETDEWEB)

    Gill, Lance [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division; Beste, Ariana [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Joint Institute for Computational Sciences (JIBS); Univ. of Tennessee, Knoxville, TN (United States); Chen, Banghao [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division; Li, Meijun [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division; Mann, Amanda K. P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division; Overbury, Steven H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division; Hagaman, Edward W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division

    2017-03-22

    1H nuclear magnetic resonance (NMR) spectroscopy was used to study hydroxylic surface species on ceria nanocubes, a crystalline, high-surface-area CeO2 that presents mostly (100) facets. Water adsorption and desorption experiments in combination with fast magic angle spinning (MAS, 20–40 kHz) 1H NMR provide high-resolution 1H spectra that allow the observation of ten resonance bands (water or hydroxyl) on or under the (100) surface. Assignments were made using a combination of adsorption and temperature-programmed desorption, quantitative spin counting, deuterium exchange, spin–lattice (T1) and spin–spin (T2) relaxation, and DFT calculations. In air, the (100) surface exists as a fully hydroxylated surface. Water adsorption and dissociation on dry ceria surfaces occur first at oxygen vacancies, but Ce3+ centers are not required since water dissociation is barrier-less on the fully oxidized surface. Surface $-$OH functionality occurs in two resolved bands representing isolated $-$OH (1 ppm) and hydrogen-bonded $-$OH (9 ppm), the latter being dominant. Deuterium exchange of surface hydroxyls with D2O does not occur under mild or forcing conditions. Despite large differences in the T1 of surface hydroxyls and physisorbed water, surface hydroxyl T1 values are independent of the presence or absence of physisorbed water, demonstrating that the protons within these two functional group pools are not in intimate contact. These observations show that, once hydroxylated, the surface $-$OH functionality preferentially forms hydrogen bonds with surface lattice oxygen, i.e., the hydroxylated (100) surface of ceria is hydrophobic. Near this surface it is energetically more favorable for physisorbed water to hydrogen bond to itself rather than to the surface. DFT calculations support this notion. Impurity Na+ remaining in incompletely washed ceria nanocubes

  1. Chemical generation of iodine atoms

    Energy Technology Data Exchange (ETDEWEB)

    Hewett, Kevin B. [Directed Energy Directorate, Air Force Research Laboratory, 3550 Aberdeen Avenue SE, Kirtland AFB, NM 87117-5776 (United States)]. E-mail: kevin.hewett@kirtland.af.mil; Hager, Gordon D. [Directed Energy Directorate, Air Force Research Laboratory, 3550 Aberdeen Avenue SE, Kirtland AFB, NM 87117-5776 (United States); Crowell, Peter G. [Northrup Grumman Information Technology, Science and Technology Operating Unit, Advanced Technology Division, P.O. Box 9377, Albuquerque, NM 87119-9377 (United States)

    2005-01-10

    The chemical generation of atomic iodine using a chemical combustor to generate the atomic fluorine intermediate, from the reaction of F{sub 2} + H{sub 2}, followed by the production of atomic iodine, from the reaction of F + HI, was investigated. The maximum conversion efficiency of HI into atomic iodine was observed to be approximately 75%, which is in good agreement with the theoretical model. The conversion efficiency is limited by the formation of iodine monofluoride at the walls of the combustor where the gas phase temperature is insufficient to dissociate the IF.

  2. Iodine Deficiency

    Science.gov (United States)

    ... Fax/Phone Home » Iodine Deficiency Leer en Español Iodine Deficiency Iodine is an element that is needed ... world’s population remains at risk for iodine deficiency. Iodine Deficiency FAQs WHAT IS THE THYROID GLAND? The ...

  3. A computational study on the energetics and mechanisms for the dissociative adsorption of SiH{sub x}(x = 1–4) on W(1 1 1) surface

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Y.H.; Raghunath, P.; Lin, M.C., E-mail: chemmcl@emory.edu

    2016-01-30

    Graphical abstract: - Highlights: • Behavior of the SiH{sub x} species on the W surface under cat-CVD conditions. • The adsorption and dissociation mechanisms of SiH{sub x}(x = 1–4) species on W(1 1 1) surface. • H-migration to its neighboring W atoms is more favorable compared to H{sub 2} elimination. - Abstract: The adsorption and dissociation mechanisms of SiH{sub x}(x = 1–4) species on W(1 1 1) surface have been investigated by using the periodic density functional theory with the projector-augmented wave approach. The adsorption of all the species on four surface sites: top (T), bridge (B), shallow (S), and deep (D) sites have been analyzed. For SiH{sub 4} on a top site, T-SiH{sub 4(a)}, it is more stable with an adsorption energy of 2.6 kcal/mol. For SiH{sub 3}, the 3-fold shallow site is most favorable with adsorption energy of 46.0 kcal/mol. For SiH{sub 2}, its adsorption on a bridge site is most stable with 73.0 kcal/mol binding energy, whereas for SiH and Si the most stable adsorption configurations are on 3-fold deep sites with very high adsorption energies, 111.8 and 134.7 kcal/mol, respectively. The potential energy surfaces for the dissociative adsorption of all SiH{sub x} species on the W(1 1 1) surface have been constructed using the CINEB method. The barriers for H-atom migration from SiH{sub x(a)} to its neighboring W atoms, preferentially on B-sites, were predicted to be 0.4, 1.0, 4.5 and, 8.0 kcal/mol, respectively, for x = 4, 3, 2, and 1, respectively. The adsorption energy of the H atom on a bridge site on the clean W(1 1 1) surface was predicted to be 65.9 kcal/mol, which was found to be slightly affected by the co-adsorption of SiH{sub x−1} within ± 1 kcal/mol.

  4. O{sub 2} adsorption and dissociation on the Pd{sub 13-n}Ni{sub n}@Pt{sub 42} (n = 0, 1, 12, and 13) tri-metallic nanoparticles: A DFT study

    Energy Technology Data Exchange (ETDEWEB)

    Li, Sha; Yang, Yongpeng; Huang, Shiping, E-mail: huangsp@mail.buct.edu.cn

    2017-07-15

    Highlights: • O{sub 2} adsorption and dissociation on Pd{sub 13-n}Ni{sub n}@Pt{sub 42} NPs are performed by DFT. • Adsorption energies of O{sub 2} and O are strongly affected by the coordination number. • Adsorption energy and d-band center displays the opposite change tendency. • Ni{sub 13}@Pt{sub 42} is the most active catalyst among Pd{sub 13-n}Ni{sub n}@Pt{sub 42} (n = 0, 1, 12, and 13) NPs. - Abstract: Density functional theory calculations are performed to investigate O{sub 2} adsorption and dissociation on the icosahedral Pd{sub 13-n}Ni{sub n}@Pt{sub 42} (n = 0, 1, 12, and 13) tri-metallic nanoparticles. The parallel adsorption of O{sub 2} on Pd{sub 13-n}Ni{sub n}@Pt{sub 42} (n = 0, 1, 12, and 13) is stronger than the vertical adsorption. The adsorption of O{sub 2} on the bridge site (B1) is favorable in the Pd{sub 13-n}Ni{sub n}@Pt{sub 42} (n = 0, 1, 12, and 13) nanoparticles, while the adsorption of O atom on the hollow site (H1) is preferred. The adsorption energies of O{sub 2} and O are strongly affected by the coordination number. Low coordination site shows strong adsorption of O{sub 2} and O on the Pd{sub 13-n}Ni{sub n}@Pt{sub 42} (n = 0, 1, 12, and 13) nanoparticles. The adsorption energies of O{sub 2} and O atoms are found to be correlated well with the d-band center of surface Pt. For the Pd{sub 13-n}Ni{sub n}@Pt{sub 42} (n = 0, 1, 12, and13) nanoparticles catalysts, the ORR activity follows the order of Ni{sub 13}@Pt{sub 42} > Pd{sub 13}@Pt{sub 42} > Pd{sub 12}Ni{sub 1}@Pt{sub 42} > Pd{sub 1}Ni{sub 12}@Pt{sub 42}, illustrating that the Ni{sub 13}@Pt{sub 42} is the strongest ORR activity among the Pd{sub 13-n}Ni{sub n}@Pt{sub 42} (n = 0, 1, 12, and13) nanoparticles catalysts. Our results have important significance to understand the mechanism of O{sub 2} dissociation on the Pd{sub 13-n}Ni{sub n}@Pt{sub 42} (n = 0, 1, 12, and 13) tri-metallic nanoparticles.

  5. Chemisorption of organic iodine compounds forming from fission isotopes of radioactive iodine

    International Nuclear Information System (INIS)

    Tot, G.; Galina, F.; Zel'd, E.

    1977-01-01

    Studied is ethyl iodine adsorption, labelled by iodine 131, on palladium black and on aluminium oxide activized by palladium. The desorption of adsorbed iodine in the temperature range of 20-600 deg C by the mass spectroscopy and thermal gravimetric methods was investigated. At the ethyl iodine and palladium interaction the bond between carbon and iodine in the ethyl iodine molecule breaks down and extracting iodine reacts with palladium, forming a stable compound at high temperatures. Desorption of adsorbed iodine is insignificant up to the temperatures of 250-300 deg C. Thus, sorbents, containing palladium, may be successfully applied for iodine absorption from the organic iodine compounds. These compounds spontaneously appear from the iodine fragment ratio isotopes during their interaction with some environmental organic impurities

  6. Iodine volatility

    International Nuclear Information System (INIS)

    Beahm, E.C.; Shockley, W.E.

    1984-01-01

    The ultimate aim of this program is to couple experimental aqueous iodine volatilities to a fission product release model. Iodine partition coefficients, for inorganic iodine, have been measured during hydrolysis and radiolysis. The hydrolysis experiments have illustrated the importance of reaction time on iodine volatility. However, radiolysis effects can override hydrolysis in determining iodine volatility. In addition, silver metal in radiolysis samples can react to form silver iodide accompanied by a decrease in iodine volatility. Experimental data are now being coupled to an iodine transport and release model that was developed in the Federal Republic of Germany

  7. Iodine Deficiency

    NARCIS (Netherlands)

    Zimmermann, M.B.

    2009-01-01

    Iodine deficiency has multiple adverse effects in humans, termed iodine deficiency disorders, due to inadequate thyroid hormone production. Globally, it is estimated that 2 billion individuals have an insufficient iodine intake, and South Asia and sub-Saharan Africa are particularly affected.

  8. Radionuclide Basics: Iodine

    Science.gov (United States)

    ... Centers Radiation Protection Contact Us Share Radionuclide Basics: Iodine Iodine (chemical symbol I) is a chemical element. ... in the environment Iodine sources Iodine and health Iodine in the Environment All 37 isotopes of iodine ...

  9. Sorption of iodine onto Japanese soils

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Satoshi [National Inst. of Radiological Sciences, Hitachinaka, Ibaraki (Japan). Nakaminato Lab. Branch

    1996-04-01

    Soils were collected from various regions of Japan. Iodine concentrations in the soils were quantitatively determined. The adsorption ratio and the distribution coefficients of iodine onto the soils were derived and effects of co-existing ions were studied. (J.P.N.)

  10. Sorption of iodine onto Japanese soils

    International Nuclear Information System (INIS)

    Yoshida, Satoshi

    1996-01-01

    Soils were collected from various regions of Japan. Iodine concentrations in the soils were quantitatively determined. The adsorption ratio and the distribution coefficients of iodine onto the soils were derived and effects of co-existing ions were studied. (J.P.N.)

  11. The method of quantitative determination of iodine in acetic acid

    International Nuclear Information System (INIS)

    Sukhomlinov, A.B.; Kalinchenko, N.B.

    1988-01-01

    Method for separate determination of J 2 and J - concentrations in acetic acid is suggested. Iodine concentration in acetic acid is determined by measuring potential of iodine-selective electrode first in the initial solution of acetic acid, where molecular iodine dissociation equals 0.5, and then in acetic acid, with alkali (NaOH) addition up to pH > 3, where molecular iodine dissociation equals 1. Determination is conducted in 5x10 -7 -5x10 -6 mol/l concentration range with relative standard deviation not more than 0.1. 1 fig

  12. Iodinated bleomycin

    International Nuclear Information System (INIS)

    Lunghi, F.; Riva, P.; Assone, F.; Villa, M.; Plassic, G.

    1978-01-01

    Bleomycin was labelled with iodine-131 by the iodine monochloride method. Iodination did not alter the chemical and chromatographic features and ''in vitro'' stability studies on freeze-dried 131 I-Bleomycin having a specific activity of 1 mCi/mg, stored at different temperatures, showed no appreciable variation of the free-iodine content. Tissue distribution of 131 I-Bleomycin has been evaluated in tumor bearing rats. Patients have been injected with 0.5-1.0 mCi of 131 I-Bleomycin corresponding to a maximum of 1.5 mg. No adverse reactions have been observed. Total body scans have been performed at 2, 6, 24 and 48 hours after injection. The iodinated Bleomycin was rapidly distributed and cleared from the body and showed an early uptake in the neoplastic tissue. A diagnostic accuracy of 90% has been observed in malignant deseases, while no false positive results have been, at the moment, recorded. (author)

  13. Iodine poisoning

    Science.gov (United States)

    ... Iodine is also used during the production of methamphetamine. Note: This list may not be all inclusive. ... breathing machine (ventilator) Blood and urine tests Chest x-ray EKG (electrocardiogram, or heart tracing) Fluids through a ...

  14. Iodine in diet

    Science.gov (United States)

    Diet - iodine ... Many months of iodine deficiency in a person's diet may cause goiter or hypothyroidism . Without enough iodine, ... and older children. Getting enough iodine in the diet may prevent a form of physical and intellectual ...

  15. Iodine removing means

    International Nuclear Information System (INIS)

    Takeshima, Masaki.

    1975-01-01

    Object: To employ exhaust gas from an incinerator to effect regeneration of an adsorbent such as active carbon which has adsorbed a radioactive gas such as iodine contained in the ventilating system exhaust gas of a boiling water reactor power plant. Structure: Radioactive exhaust gas such as iodine, xenon and krypton is led to an active carbon adsorbing means for removal through adsorption. When the adsorbing function of the active carbon adsorption means is reduced, the exhaust gas discharged from the incinerator is cooled down to 300 0 C and then caused to flow into the active carbon layer, and after depriving it of sulfur dioxide gas, oxides of nitrogen, daughter nuclides resulting from attenuation of radioactive gas and so forth, these being adsorbed by the carbon active layer, it is led again to the incinerator, whereby the radioactivity accompanying the regenerated gas is sealed as ash within the incinerator. Further, similarly accompanying fine active carbon particles and the like are utilized as a heat source for the incinerator. (Kamimura, M.)

  16. Iodine ion adsorption and the electric double layer structure at a mercury electrode in aqueous potassium iodide solutions containing 0,05 M thiourea

    International Nuclear Information System (INIS)

    Damaskin, B.B.; Polyanovskaya, N.S.

    1988-01-01

    Electrocapillary measurements were used to obtain isotherms of specific adsorption of I - anions on the Hg/H 2 O boundary from KI+0.05 M of thiourea (TU) solutions. Is is shown that these data can be described by a simple varial isotherm, but disagree with Grahame-Parsons model. It follows from the suggested model interpretation of obtained results that electric centers of specifically adsorbed anions are displaced during coadsorption of TU molecules to the side of Helmholtz external plane, leading to disappearance of Esin-Markov effect

  17. Iodine Satellite

    Science.gov (United States)

    Kamhawi, Hani; Dankanich, John; Martinez, Andres; Petro, Andrew

    2015-01-01

    The Iodine Satellite (iSat) spacecraft will be the first CubeSat to demonstrate high change in velocity from a primary propulsion system by using Hall thruster technology and iodine as a propellant. The mission will demonstrate CubeSat maneuverability, including plane change, altitude change and change in its closest approach to Earth to ensure atmospheric reentry in less than 90 days. The mission is planned for launch in fall 2017. Hall thruster technology is a type of electric propulsion. Electric propulsion uses electricity, typically from solar panels, to accelerate the propellant. Electric propulsion can accelerate propellant to 10 times higher velocities than traditional chemical propulsion systems, which significantly increases fuel efficiency. To enable the success of the propulsion subsystem, iSat will also demonstrate power management and thermal control capabilities well beyond the current state-of-the-art for spacecraft of its size. This technology is a viable primary propulsion system that can be used on small satellites ranging from about 22 pounds (10 kilograms) to more than 1,000 pounds (450 kilograms). iSat's fuel efficiency is ten times greater and its propulsion per volume is 100 times greater than current cold-gas systems and three times better than the same system operating on xenon. iSat's iodine propulsion system consists of a 200 watt (W) Hall thruster, a cathode, a tank to store solid iodine, a power processing unit (PPU) and the feed system to supply the iodine. This propulsion system is based on a 200 W Hall thruster developed by Busek Co. Inc., which was previously flown using xenon as the propellant. Several improvements have been made to the original system to include a compact PPU, targeting greater than 80 percent reduction in mass and volume of conventional PPU designs. The cathode technology is planned to enable heaterless cathode conditioning, significantly increasing total system efficiency. The feed system has been designed to

  18. The distribution and transformations of iodine in the environment

    International Nuclear Information System (INIS)

    Whitehead, D.C.

    1984-01-01

    Iodine in the atmosphere is derived largely from seawater. It is probable that the biological production of methyl iodide is important in this transfer. Subsequent photolytic dissociation and oxidation of the methyl iodide, together with other inputs, with partial sorption of the products by aerosols, results in the atmospheric iodine being distributed between various gaseous and particulate forms. Atmospheric iodine is the major source of the iodine in soils, and the process of enrichment continues throughout soil formation and development until ultimately an equilibrium concentration is attained. The atmosphere is also a direct source of iodine for plants, and in some situations may be more important than the soil. Iodine may be lost from soils by leaching, volatilization, and removal in crops. The amounts of iodine reported in groundwaters, and in rivers and lakes remote from human activity, suggest that some leaching of iodine is widespread. Increased amounts of iodine occur in rivers receiving effluent from sewage works. Milk and milk products are now major dietary sources of iodine because their content is often increased by concentrate feedingstuffs supplemented with iodine and/or by the use in dairies of iodophor detergents and sterilants. (author)

  19. The behavior of gaseous iodine in sand

    International Nuclear Information System (INIS)

    Takahashi, Kanji

    1974-01-01

    Radioactive iodine gas was passed through 10 different sands collected at rivers and hills. The relation between the amount of the loaded gas and the amount of adsorbed gas was determined at room temperature, 50 -- 60 0 C, and 90 -- 100 0 C under humidity of 2 sand. This amount was about 1 -- 3 times as much as that of monomolecular membrane adsorption, 0.2 -- 0.3 μg/cm 2 . The decrease of adsorption amount that accompanies the increase of humidity is attributable to the decrease of effective surface area of sand due to the presence of water. The transport of iodine in sand was studied by passing gaseous iodine through a glass tubing packed with sand. The distribution in the flow direction of iodine indicated that the ease of desorption depends upon the situation of adsorption. Easily desorbed case was named Henry type adsorption. Hardly desorbed case was named absorption type. Discussion is made on experimental results. (Fukutomi, T.)

  20. A Possibility for Construction of an Iodine Cleaning System Based on Doping for π-Conjugated Polymers

    Directory of Open Access Journals (Sweden)

    Hiromasa Goto

    2011-05-01

    Full Text Available An iodine accumulation method using polyaniline (PANI and a textile composite is proposed. PANI/pulp paper sheets prepared by a paper making technique are suitable for iodine adsorption, because of good processability. The PANI-based paper sheets can be applied for iodine cleanup as air filters, water filters, and floorcloth. This concept may lead to a development of an iodine cleaning machine or iodine shield cloth based on π-conjugated polymer composites. In-situ vapor phase doping of iodine, observation of surface images, and IR measurements are carried out to examine iodine doping function for the PANI/pulp paper sheets.

  1. An Investigation into the Effects of Mn Promotion on the Activity and Selectivity of Co/SiO2 for Fischer - Tropsch Synthesis: Evidence for Enhanced CO Adsorption and Dissociation

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Gregory R.; Werner, Sebastian; Bell, Alexis T. (LBNL); (UCB)

    2016-03-04

    Mn is an effective promoter for improving the activity and selectivity of Co-based Fischer-Tropsch synthesis (FTS) catalysts, but the mechanism by which this promoter functions is poorly understood. The work reported here was aimed at defining the manner in which Mn interacts with Co and determining how these interactions affect the activity and selectivity of Co. Detailed measurements are reported for the kinetics of FTS as a function of Mn/Co ratio, temperature, and reactant partial pressure. These data are described by a single, two-parameter rate expression. Mn promotion was found to increase both the apparent rate constant for CO consumption and the CO adsorption constant. Further evidence for enhanced CO adsorption and dissociation was obtained from measurements of temperature-programmed desorption of CO and CO disproportionation rates, respectively. Our quantitative analysis of elemental maps obtained by STEM-EDS revealed that the promoter accumulates preferentially on the surface of Co nanoparticles at low Mn loadings, resulting in a rapid onset of improvements in the product selectivity as the Mn loading increases. For catalysts prepared with loadings higher than Mn/Co = 0.1, the additional Mn accumulates in the form of nanometer-scale particles of MnO on the support. In situ IR spectra of adsorbed CO show that Mn promotion increases the abundance of adsorbed CO with weakened C-O bonds. Furthermore, it is proposed that the cleavage of the C-O bond is promoted through Lewis acid-base interactions between the Mn2+ cations located at the edges of MnO islands covering the Co nanoparticles and the O atom of CO adsorbates adjacent to the MnO islands. The observed decrease in selectivity to CH4 and the increased selectivity to C5+ products with increasing Mn/Co ratio are attributed to a decrease in the ratio of adsorbed H to CO on the surface of the supported Co nanoparticles.

  2. Gravimetric determination of the iodine number of carbon black

    International Nuclear Information System (INIS)

    Murphy, L.J. Jr.

    1991-01-01

    This paper discusses a gravimetric method for the determination of the iodine adsorption number of carbon black. It comprises determining the concentration of an accurately weighed iodine blank solution by adding a standardized titrant to the iodine solution until a titration endpoint is reached and determining the concentration of the iodine solution by accurately weighing the amount of the standardized titrant necessary to reach the endpoint, accurately weighing an amount of carbon black and adding an appropriate amount of an accurately weighed portion of the iodine solution, equilibrating the carbon black-iodine solution mixture, adding the standardized titrant to an accurately weighed portion of the supernatant from the carbon black-iodine mixture until a titration endpoint is reached and determining the concentration of the supernatant by accurately weighing the amount of the standardized titrant necessary to reach the endpoint, wherein the titration endpoint of the supernatant is obtained using an indicating and a reference electrode, and calculating the iodine adsorption number of the carbon black based on the gravimetrically determined concentration of the titrant, the iodine solution, and the supernatant

  3. Simulation of ISTP-EPICUR Iodine Chemistry Tests with RAIM

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Han-Chul; Cho, Yeong-Hun; Jang, Dong-Ju; Ryu, Myung-Hyun [Nuclear Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2014-10-15

    The amount of iodine release largely depends on its volatility in the containment. Iodine has several chemical forms including aerosols, vapor, and gas. Among them gaseous iodine such as I{sub 2} and organic iodide are dominating due to their high volatility. Therefore, such iodine behavior has been extensively examined. Korea Institute of Nuclear Safety (KINS) has been joining the relevant international programs such as ISTP-EPICUR, OECD-BIP and OECD-STEM. In the course of this study, a simple iodine model, RAIM (Radio-Active Iodine chemistry Model) has been developed, based on the IMOD methodology and other previous studies. This model deals with chemical reactions associated with formation and destruction of iodine species in the containment atmosphere and the sump in a simple manner, as shown in Fig. 1. It also treats adsorption and desorption of volatile iodine on the paint surface. The iodine species modeled are inorganic volatile iodine, organic iodides of high volatility (HVRI) and low volatility (LVRI), non-volatiles, non-aqueous iodine, and iodine oxide aerosols (IO{sub x}). Many other material participating in the iodine reactions, e.g., air radiolysis products (ARP) such as ozone, are also modeled. This paper especially shows the analysis results after addition of gaseous reaction model to RAIM, which was further accompanied by adjustments of the existing reaction rate constants even for the aqueous reactions. After integration of iodine reaction models for gas and aqueous phase, RAIM was applied the S1-9 and S1-11 tests which were carried out in aqueous phase. In addition, re-analysis of the S2-6-5-2 test, for which iodine-loaded coupons were tested in gas phase, was also performed.

  4. Spectroscopic constants and the potential energy curve of the iodine weakly bound 0+g state correlating with the I(2P1/2) + I(2P1/2) dissociation limit

    International Nuclear Information System (INIS)

    Akopyan, M E; Baturo, V V; Lukashov, S S; Poretsky, S A; Pravilov, A M

    2013-01-01

    The stepwise three-step three-colour aser excitation scheme and rotational as well as rovibrational energy transfer processes in the 0 + g state induced by collisions with He and Ar atoms are used for determination of rovibronic level energies of the weakly bound 0 + g state correlating with the I( 2 P 1/2 ) + I( 2 P 1/2 ) dissociation limit. Dunham coefficients of the state, Y i0 (i = 0–3), Y i1 (i = 0–3) and Y 02 for the v 0 g + = 0–16 and J 0 g + ≈ 14–135 ranges as well as the dissociation energy of the state, D e , and equilibrium I–I distance of the state, R e , are determined. The potential energy curve of the state constructed using these constants is also reported. (paper)

  5. Iodine and Pregnancy

    OpenAIRE

    Yarrington, Christina; Pearce, Elizabeth N.

    2011-01-01

    Iodine is a necessary element for the production of thyroid hormone. We will review the impact of dietary iodine status on thyroid function in pregnancy. We will discuss iodine metabolism, homeostasis, and nutritional recommendations for pregnancy. We will also discuss the possible effects of environmental contaminants on iodine utilization in pregnant women.

  6. Absorbing method of iodine in radioactive gaseous wastes

    International Nuclear Information System (INIS)

    Fukutome, Yutaka; Mifuji, Hiroshi; Ito, Sakae.

    1983-01-01

    Purpose: To maintain an iodine adsorbing efficiency at a high level by keeping the adsorbing atmosphere to more than a predetermined temperature to thereby suppress the degradation and the activity reduction in zeolite. Method: Adsorption and desorption-regeneration of gaseous wastes are performed in parallel by heating gaseous wastes in a heater and switchingly supplying the same to adsorption columns by way of valve operation. Processed gases are cooled in a cooler and desorbed gases are supplied to an after-treatment device to eliminate or recover iodine 131. In the adsorption column, iodine in gaseous wastes is adsorbed to remove by using zeolite, wherein the adsorbing atmosphere is kept at a temperature higher than 40 0 C. This can prevent the formation of an aqueous HNO 3 solution from NO 2 and H 2 O contained in the gaseous wastes and prevent the degradation of the zeolite adsorption layer. (Kawakami, Y.)

  7. Apparatus for eliminating radioactive iodine from off-gases in a nuclear fuel reprocessing plant

    International Nuclear Information System (INIS)

    Kondo, Yoshikazu; Kurihara, Koichi.

    1983-01-01

    Purpose: To improve the eliminating efficiency of an iodine eliminating apparatus using a dry process. Constitution: A hydrogen iodide conversion device and an organic iodine decomposing device are disposed prior to and subsequent to an adsorption tower using adsorbents for the removal of the iodine in a processing gas line through which radioactive iodine containing gases are passed. Elementary iodine and organic iodine can be eliminated by such simple devices. In the case of the dry processing by using the adsorbents, those adsorbents incorporated with inexpensive metal such as lead and copper can be used for the removal of the organic iodine and the radioactive iodine-adsorbing material can be processed as wastes, whereby iodine can effectively be eliminated at a reduced cost. (Moriyama, K.)

  8. Iodine intake in Denmark

    International Nuclear Information System (INIS)

    Pedersen, K.M.; Noehr, S.B.; Laurberg, P.

    1997-01-01

    Iodine deficiency with a high frequency of goitre and, in severely affected areas, cretinism is common in some areas of the world. In Denmark the iodine intake as evaluated by urinary iodine excretion has been at a stable low level for many years, except for the part of the population now taking iodine supplementation as part of vitamin/mineral preparations. The iodine intake is lowest in the western part to the country where an epidemiological study of elderly subjects has demonstrated a high frequency of goitre and hyperthyroidism in women. This supports the suggestion of a controlled moderate increase in iodine intake via an iodine supplementation program. (au) 40 refs

  9. Iodine intake in Ireland

    International Nuclear Information System (INIS)

    Smith, P.P.A.; Hetherton, A.M.; O'Carroll, D.; Smith, D.F.; O'Halloran, M.J.; O'Donovan, D.K.

    1988-01-01

    A study of urinary iodine excretion and thyroid gland uptake of radioactive iodine 131 I was undertaken in the Dublin area with a view to providing data on the current iodine status in Ireland. A mean urinary iodine excretion of 118±82μg/gram creatinine (Median 96) obtained from 821 subjects attending general hospital outpatient clinics in the Dublin area in 1987, while excluding severe iodine deficiency in this particular cohort, obscured the fact that 250 (30%) had iodine excretion values ≤70 μ/g creatinine, a value approximating to the minimum daily iodine requirement. The results provide sufficient evidence of sporadic iodine deficiency to justify a more widespread study of the iodine status of the Irish population with a view to making recommendations on the possible need for iodine prophylaxis

  10. FY-2016 Methyl Iodide Higher NOx Adsorption Test Report

    Energy Technology Data Exchange (ETDEWEB)

    Soelberg, Nicholas Ray [Idaho National Lab. (INL), Idaho Falls, ID (United States); Watson, Tony Leroy [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-09-01

    Deep-bed methyl iodide adsorption testing has continued in Fiscal Year 2016 under the Department of Energy (DOE) Fuel Cycle Technology (FCT) Program Offgas Sigma Team to further research and advance the technical maturity of solid sorbents for capturing iodine-129 in off-gas streams during used nuclear fuel reprocessing. Adsorption testing with higher levels of NO (approximately 3,300 ppm) and NO2 (up to about 10,000 ppm) indicate that high efficiency iodine capture by silver aerogel remains possible. Maximum iodine decontamination factors (DFs, or the ratio of iodine flowrate in the sorbent bed inlet gas compared to the iodine flowrate in the outlet gas) exceeded 3,000 until bed breakthrough rapidly decreased the DF levels to as low as about 2, when the adsorption capability was near depletion. After breakthrough, nearly all of the uncaptured iodine that remains in the bed outlet gas stream is no longer in the form of the original methyl iodide. The methyl iodide molecules are cleaved in the sorbent bed, even after iodine adsorption is no longer efficient, so that uncaptured iodine is in the form of iodine species soluble in caustic scrubber solutions, and detected and reported here as diatomic I2. The mass transfer zone depths were estimated at 8 inches, somewhat deeper than the 2-5 inch range estimated for both silver aerogels and silver zeolites in prior deep-bed tests, which had lower NOx levels. The maximum iodine adsorption capacity and silver utilization for these higher NOx tests, at about 5-15% of the original sorbent mass, and about 12-35% of the total silver, respectively, were lower than for trends from prior silver aerogel and silver zeolite tests with lower NOx levels. Additional deep-bed testing and analyses are recommended to expand the database for organic iodide adsorption and increase the technical maturity if iodine adsorption processes.

  11. Ultrahigh iodine adsorption in porous organic frameworks

    KAUST Repository

    Pei, Cuiying; Ben, Teng; Xu, Shixian; Qiu, Shilun

    2014-01-01

    sorption isotherms at 298 K and 313 K of JUC-Z2, reached -51.1 kJ mol-1, which was much higher than the coverage of PAF-1 (-14.9 kJ mol-1). Raman measurement confirmed the polyiodide to be I5 - in POFs. Furthermore, solvents with different polarities

  12. Iodine Gas Trapping using Granular Porous Bismuth

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jae Hwan; Shin, Jin Myeong; Park, Jang Jin; Park, Geun Il [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Yim, Mansung [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2014-05-15

    {sup 129}I is a radionuclide with a very long half-life of 1.57 Χ 10{sup 7} years and has negative health effects to the human body. Therefore, the emission of {sup 129}I into the air is closely regulated by the Environmental Protection Agency (EPA). Many methods for trapping gaseous {sup 129}I have been developed thus far, including wet scrubbing and adsorption using silver loaded zeolites. Although wet scrubbing can effectively remove iodine, it suffers from corrosion of the vessel due to high concentration of the scrubbing solution. Silver loaded zeolites also show effectiveness in capturing {sup 129}I gas, yet weak thermal stability of physisorbed iodine remains a challenge. We studied a novel and facile method to trap iodine gas using bismuth. Granular bismuth having many pores was synthesized using bismuth nitrate and polyvinyl alcohol as a bismuth precursor and pore forming agent, respectively. Reaction of iodine and our samples resulted in an iodine capturing capacity of more than 2 times that of the commercial grade silver exchanged zeolite (AgX). Granular porous bismuths synthesized using bismuth nitrate and PVA show a promising performance in capturing iodine gas. The use of bismuth in trapping {sup 129}I gas can reduce the process cost as bismuth is cheap. Further study is going on to improve the mechanical property of granular porous bismuths for their easy handling.

  13. Iodine Gas Trapping using Granular Porous Bismuth

    International Nuclear Information System (INIS)

    Yang, Jae Hwan; Shin, Jin Myeong; Park, Jang Jin; Park, Geun Il; Yim, Mansung

    2014-01-01

    129 I is a radionuclide with a very long half-life of 1.57 Χ 10 7 years and has negative health effects to the human body. Therefore, the emission of 129 I into the air is closely regulated by the Environmental Protection Agency (EPA). Many methods for trapping gaseous 129 I have been developed thus far, including wet scrubbing and adsorption using silver loaded zeolites. Although wet scrubbing can effectively remove iodine, it suffers from corrosion of the vessel due to high concentration of the scrubbing solution. Silver loaded zeolites also show effectiveness in capturing 129 I gas, yet weak thermal stability of physisorbed iodine remains a challenge. We studied a novel and facile method to trap iodine gas using bismuth. Granular bismuth having many pores was synthesized using bismuth nitrate and polyvinyl alcohol as a bismuth precursor and pore forming agent, respectively. Reaction of iodine and our samples resulted in an iodine capturing capacity of more than 2 times that of the commercial grade silver exchanged zeolite (AgX). Granular porous bismuths synthesized using bismuth nitrate and PVA show a promising performance in capturing iodine gas. The use of bismuth in trapping 129 I gas can reduce the process cost as bismuth is cheap. Further study is going on to improve the mechanical property of granular porous bismuths for their easy handling

  14. Radioactive Iodine Treatment for Hyperthyroidism

    Science.gov (United States)

    ... Balance › Radioactive Iodine for Hyperthyroidism Fact Sheet Radioactive Iodine for Hyperthyroidism April, 2012 Download PDFs English Zulu ... prepare for RAI or surgery. How does radioactive iodine treatment work? Iodine is important for making thyroid ...

  15. Iodine and thyroid function

    Directory of Open Access Journals (Sweden)

    Hye Rim Chung

    2014-03-01

    Full Text Available Severe iodine deficiency causes hypothyroidism that results in impaired somatic growth and motor development in children. Mild and moderate iodine deficiencies cause multifocal autonomous growth of thyroid, which results in thyrotoxicosis. On the other hand, iodine excess is associated with the development of hypothyroidism and thyroid autoimmunity. In areas of iodine deficiency, a sudden increase in iodine intake is associated with transient hyperthyroidism. Recent studies demonstrated that long-term thyroid function of subjects who experienced both iodine deficiency and iodine excess during childhood tended to be abnormal despite optimization of their current iodine intake. Iodine status in the Korean Peninsula is very unique because people in the Republic of Korea have been shown to have predominantly excessive iodine levels, whereas the Democratic People's Republic of Korea is known to be an iodine-deficient area. Further research is warranted to verify the optimal ranges of iodine intake and to clarify the effects of iodine intake on thyroid disorders in the Korean Peninsula.

  16. CO dissociation on magnetic Fen clusters

    KAUST Repository

    Jedidi, Abdesslem; Markovits, Alexis; Minot, Christian; Abderrabba, Manef Ben; Van Hove, Michel A.

    2014-01-01

    triangular facet of the nanoparticle. Dissociation becomes easier when the cluster size increases. Then, the C atom is bonded to a square facet that is generated as a result of the adsorption if it does not yet exist in the bare cluster, while the O atom

  17. Spectroscopic constants and potential energy curve of the iodine weakly bound 1u state correlating with the I(2P1/2) + I(2P1/2) dissociation limit

    International Nuclear Information System (INIS)

    Akopyan, M E; Baturo, V V; Lukashov, S S; Poretsky, S A; Pravilov, A M

    2015-01-01

    The stepwise three-step three-color laser population of the I 2 (β1 g , ν β , J β ) rovibronic states via the B0 u + , ν B , J B rovibronic states and rovibronic levels of the 1 u (bb) and 0 g + (bb) states mixed by hyperfine interaction is used for determination of rovibronic level energies of the weakly bound I 2 (1 u (bb)) state. Dunham coefficients of the state, Y i0 (i = 0–3), Y i1 (i = 0–2), Y 02 and Y 12 for the v 1 u  = 1–5, 8, 10, 15 and J 1 u  ≈ 9–87 ranges, the dissociation energy of the state, D e , and equilibrium I–I distance, R e , as well as the potential energy curve are determined. There are aperiodicities in the excitation spectrum corresponding to the β, ν β  = 23, J β  ← 1 u (bb), ν 1u  = 4, 5, J 1u progressions in the I 2  + Rg = He, Ar mixture, namely, a great number of lines which do not coincide with the R or P line progressions. Their positions conflict with the ΔJ-even selection rule. Furthermore, they do not correspond to the ΔJ-odd progression. (paper)

  18. Iodination of phenol

    International Nuclear Information System (INIS)

    Christiansen, J.V.; Feldthus, A.; Carlsen, L.

    1990-01-01

    Phenol is iodinated in aqueous solution at pH 5 (acetate buffer) by elemental iodine or, if the iodine is present as iodide, enzymatically controlled by peroxidases. Generally mono-, di- and triiodophenols are obtained, the overall product composition being virtually identical for the two iodination modes. However, there is a tendency to a higher para to ortho ratio for the enzymatically controlled reaction. The mutual ratios of the single iodophenols depends on the initial concentration ratio between phenol and the iodinating species. The first step in the iodination leads preferentially to substitution in the ortho position rather than in the para position in contract to e.g. the corresponding bromination. The relative rates of the competive reactions in the combined iodination scheme has been derived. (author) 2 tabs., 3 ills., 15 refs

  19. Mobile Iodine Mineralization Based on Malachite Transformation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung Yeop; Baik, Min Hoon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    Our new method that is proposed here, however, offer drastic cost cutting by using copper. Moreover, the selectivity of iodine in anion-rich water is advantage to lower the disposal cost by reducing the radioactive waste volume. Iodide (I{sup -}) is soluble and mobile in water, so it is very difficult to capture and precipitate it with common adsorbents. Until now, various exchanger and getter materials have been developed to capture radioactive iodine in wastewater. The materials developed generally showed a good performance under acidic conditions. However, the adsorption amounts were not relatively large in neutral and high pH conditions. Furthermore, the capacity to capture iodine is limited by their properties, such as the specific surface area and adsorbing affinity. Recently, Ag-coated materials have attracted attention as adsorbents. They have shown higher uptake for I- compared to other substances, but they are costly. Our new method that is proposed here, however, offer drastic cost cutting by using copper. Moreover, the selectivity of iodine in anion-rich water is advantage to lower the disposal cost by reducing the radioactive waste volume. Radioactive iodine isotopes are characterized as volatile and mobile species that are difficult to capture by adsorbents. In our study, we developed a new way to uptake and crystallize the mobile iodide as cuprous iodide (CuI). This method will be a promising way to simply stabilize iodide in a solid form with compacted volume.

  20. Iodine deficiency and iodine excess in Jiangsu Province, China

    NARCIS (Netherlands)

    Zhao, J.

    2001-01-01

    Keywords:
    iodine deficiency, iodine excess, endemic goiter, drinking water, iodine intake, thyroid function, thyroid size, iodized salt, iodized oil, IQ, physical development, hearing capacity, epidemiology, meta-analysis, IDD, randomized trial, intervention, USA, Bangladesh,

  1. Zero-valent iron pretreatment for detoxifying iodine in liquid crystal display (LCD) manufacturing wastewater

    International Nuclear Information System (INIS)

    Lee, J.W.; Cha, D.K.; Oh, Y.K.; Ko, K.B.; Song, J.S.

    2009-01-01

    This study investigated reductive transformation of iodine by zero-valent iron (ZVI), and the subsequent detoxification of iodine-laden wastewater. ZVI completely reduced aqueous iodine to non-toxic iodide. Respirometric bioassay illustrated that the presence of iodine increase the lag phase before the onset of oxygen consumption. The length of lag phase was proportional to increasing iodine dosage. The reduction products of iodine by ZVI did not exhibit any inhibitory effect on the biodegradation. The cumulative biological oxidation associated with iodine toxicity was closely fitted to Gompertz model. When iodine-laden wastewater was continuously fed to a bench-scale activated sludge unit, chemical oxygen demand (COD) removal efficiencies decreased from above 90% to below 80% along with a marked decrease in biomass concentration. On the other hand, the COD removal efficiency and biomass concentration remained constant in the integrated ZVI-activated sludge system. Respirometric bioassay with real iodine-laden LCD manufacturing wastewater demonstrated that ZVI was effective for detoxifying iodine and consequently enhancing biodegradability of wastewater. This result suggested that ZVI pretreatment may be a feasible option for the removal of iodine in LCD processing wastewater, instead of more costly processes such as adsorption and chemical oxidation, which are commonly in the iodine-laden LCD wastewater treatment facility

  2. Iodine deficiency disorders

    Energy Technology Data Exchange (ETDEWEB)

    Ali, S M [Pakistan Council for Science and Technology, Islamabad (Pakistan)

    1994-12-31

    Iodine deficiency (IDD) is one of the common problem in the diet. Iodine deficiency as prevalence of goiter in population occurs in the mountainous areas. There is consensus that 800 million people are at risk of IDD from living in iodine deficient area and 190 million from goiter. Very high prevalence of IDD in different parts of the world are striking. It has generally observed that in iodine-deficient areas about 50% are affected with goiter, 1-5% from cretinsim and 20% from impaired mental and/or mortor function. (A.B.).

  3. The main outcomes of the OECD Behaviour of Iodine (BIP) Project

    International Nuclear Information System (INIS)

    Glowa, Glenn A.; Moore, Chris J.; Ball, Joanne M.

    2013-01-01

    Highlights: • Moisture affects the rate of iodine adsorption on paint. • Irradiation of iodine-loaded paint yields methyl iodide. • The BIP project is complimentary to the EPICUR project. • BIP results help with the interpretation of Phébus FP results. - Abstract: An Organisation for Economic Co-operation and Development (OECD) status report on iodine behaviour published in February 2007 concluded that although the understanding of iodine behaviour in containment had advanced considerably over the past several decades, there were still areas where further investigation was warranted. The OECD initiated the Behaviour of Iodine Project (BIP) to investigate two of these areas: • The interaction of iodine with painted surfaces: adsorption of iodine from the gas phase to several containment surfaces was investigated under a variety of conditions, with focus on the role of water on the adsorption of iodine onto epoxy paints. The results show that the relative humidity is very important to the deposition velocity of iodine on paint; higher humidity caused faster deposition. Adsorption parameters are a critical input for containment codes. • The formation of organic iodide from painted surfaces: gas chromatography was used to monitor the evolution of CH 3 I during the irradiation of epoxy coupons pre-loaded with iodine. The results showed that organic iodide formation is greater, and has a different temporal behaviour, when the iodine is absorbed by the paint from the aqueous phase as opposed to from the gas phase. The results also highlighted the importance of destruction of organic iodides by gas phase radiolysis to the concentration of CH 3 I. The BIP organic iodide production experiments were different, but complementary, to the experiments performed in the EPICUR (Experimental Program for Iodine Chemistry Under Radiation) facility. However, both projects share an objective of supporting the explanation of iodine behaviour in the Phébus Fission Product

  4. Marine geochemistry of iodine

    International Nuclear Information System (INIS)

    Kennedy, H.; Elderfield, H.

    1985-01-01

    Iodine has long been classified as a biophilic element with analyses showing that iodine is strongly enriched, relative to seawater concentrations in both plankton and particulate matter and that the concentration of iodine found in surface sediments is still further enriched relative to that found in the sedimenting particulate matter. The extent of enrichment of iodine relative to carbon in deep sea surface sediments has been shown to depend on the carbon accumulation rate. Iodine decomposition rates have been calculated and are shown to vary with the sedimentation rate in the same manner as has been shown for organic carbon. Vertical profiles of total dissolved iodine, iodate and iodide in interstitial waters of sediments from the north east Atlantic are characterised by three zones of reaction as identified by changes in the concentration of iodate and iodide. These reaction zones represent (i) iodide production (ii) iodide oxidation and (iii) iodate reduction. Pore water and solid phase iodine profiles from cores containing turbidite units have shown that iodine, released to pore waters as iodide during the oxidation of the organic matter, has been scavenged after diffusing upwards into a less reducing region of the sediment. (author)

  5. The iodine reactivity

    International Nuclear Information System (INIS)

    2003-01-01

    The iodine is an important element because it has long life isotopes (such as iodine 129) and a great mobility in natural media. Iodine presents a complex chemistry because of its volatility and its strong redox reactivity. The S.E.C.R. works to better understand the reactivity of this element in different natural, industrial or biological environments. It plays a part in thermochemical sites as a possible way of hydrogen formation. This seminar gives some aspects relative to the chemical reactivity of iodine, since its thermochemistry in the I/S cycles to produce hydrogen to its reactivity in the natural medium and its potential radiological impact. This document includes 4 presentations transparencies) dealing with: the 129 I cycle rejected in the low radioactive gaseous and liquid effluents of the La Hague reprocessing plant (C. Frechou); a bibliographic review of iodine retention in soils (F. Bazer-Bachi); the hydrogen production and the iodine/sulfur thermochemical cycle (role of iodine in the process); and the direct characterization by electro-spray ionization mass spectroscopy of iodine fixation by fulvic acids (P. Reiller, B. Amekraz, C. Moulin, V. Moulin)

  6. Iodine-deficiency disorders

    NARCIS (Netherlands)

    Zimmermann, M.B.; Jooste, P.L.; Pandav, C.S.

    2008-01-01

    billion individuals worldwide have insufficient iodine intake, with those in south Asia and sub-Saharan Africa particularly affected. Iodine deficiency has many adverse effects on growth and development. These effects are due to inadequate production of thyroid hormone and are termed

  7. Iodine mineral waters

    Directory of Open Access Journals (Sweden)

    Iluta Alexandru

    2011-11-01

    Full Text Available Iodine mineral waters are found especially in sub-Carpathian region, also in regions with Salif deposits. Waters are currently used iodine in drinking cure for chaps and Basedow. Are also indicated in balneology. Iodine water containing at least 1 mg L, there is pure iodine is usually given the nature of other types of mineral waters further: sodium chlorinated water (Bazna (50-70 mg iodine / l, Baile Govora (50 - 70 mg / l, Bălţăteşti (4-5 mg / l, salted Monteoru (30 mg / l, mine water mixed alkaline chlorination, sulphate, which are indicated for crenoterapie (hypo or isotonic to the bathrooms Olăneşti or Călimăneşti-Căciulata.

  8. Dissociation dynamics of methylal

    Energy Technology Data Exchange (ETDEWEB)

    Beaud, P; Frey, H -M; Gerber, T; Mischler, B; Radi, P P; Tzannis, A -P [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    The dissociation of methylal is investigated using mass spectrometry, combined with a pyrolytic radical source and femtosecond pump probe experiments. Based on preliminary results two reaction paths of methylal dissociation are proposed and discussed. (author) 4 fig., 3 refs.

  9. Iodine leaflets in chapter D5 'Distribution of iodine pills'

    International Nuclear Information System (INIS)

    1981-01-01

    Jodine leaflet A will be distributed together with iodine pills in a nuclear disaster. Iodine leaflet B is suitable for informing the public in advance. Iodine leaflet C informs physicians in a scientific way on the benefits and risk of iodine pills. (orig./HP) [de

  10. Iodine generator for reclaimed water purification

    Science.gov (United States)

    Wynveen, R. A.; Powell, J. D.; Schubert, F. H. (Inventor)

    1977-01-01

    The system disclosed is for controlling the iodine level in a water supply in a spacecraft. It includes an iodine accumulator which stores crystalline iodine, an electrochemical valve to control the input of iodine to the drinking water and an iodine dispenser. A pump dispenses fluid through the iodine dispenser and an iodine sensor to a potable water tank storage. The iodine sensor electronically detects the iodine level in the water, and through electronic means, produces a correction current control. The correction current control operates the electro-chemical iodine valve to release iodine from the iodine accumulator into the iodine dispenser.

  11. Dissociative adsorption of CCl 4 on the Fe 3O 4(1 1 1)-(2×2) selvedge of α-Fe 2O 3(0 0 0 1)

    Science.gov (United States)

    Adib, K.; Mullins, D. R.; Totir, G.; Camillone, N.; Fitts, J. P.; Rim, K. T.; Flynn, G. W.; Osgood, R. M.

    2003-02-01

    The surface reactions of CCl 4 with the Fe 3O 4(1 1 1)-(2×2) selvedge of naturally occurring α-Fe 2O 3(0 0 0 1) single-crystals have been investigated using synchrotron X-ray photoelectron spectroscopy (XPS) and temperature-programmed desorption (TPD). CCl 4 was found to dissociate on the Fe 3O 4 surface at 100 K producing chemisorbed Cl and adsorbed CCl 2. TPD shows that the large majority of the dissociatively adsorbed CCl 2 fragments extract lattice oxygen and desorb as phosgene at >275 K. However, the XPS spectra show no evidence for the formation of surface-bound phosgene, at 100 K, indicating that its formation involves two steps. The first step, dissociation, is spontaneous at 100 K, whereas the second, oxygen atom abstraction to form phosgene, requires thermal excitation. Cl chemisorption yielded two separate species, the mono- and dichloride terminations of surface iron sites. The identification of these two surface terminations is based on the coverage dependence and the surface temperature history of their Cl 2p 3/2 peak intensity. For example, heating to >450 K allows the monochloride to transform into iron dichloride, indicating Cl adatom mobility at these temperatures.

  12. 76 FR 82323 - Design, Inspection, and Testing Criteria for Air Filtration and Adsorption Units

    Science.gov (United States)

    2011-12-30

    ... Filtration and Adsorption Units AGENCY: Nuclear Regulatory Commission. ACTION: Draft regulatory guide... for Air Filtration and Adsorption Units of Postaccident Engineered-Safety-Feature Atmosphere Cleanup... testing of air filtration and iodine adsorption units of engineered-safety-feature (ESF) atmosphere...

  13. Is placental iodine content related to dietary iodine intake?

    LENUS (Irish Health Repository)

    Burns, R

    2011-08-01

    Delivery of iodine to the foetus depends not only on maternal dietary iodine intake but also on the presence of a functioning placental transport system. A role for the placenta as an iodine storage organ has been suggested, and this study compares the iodine content of placentas from women giving birth at term in Ireland and Iran, areas with median urinary iodine of 79 and 206 μg\\/l respectively.

  14. Iodine in meat in Macedonia

    International Nuclear Information System (INIS)

    Bogdanov, Bogdan; Gonev, Mihajlo; Tadzher, Isak

    2000-01-01

    Iodine deficiency in Macedonia still persists in a mild form. In 1999 the iodination of salt rose to 20 m gr iodine in Kg salt. The consumption of salt diminished after the last war from 20-30 gr salt per day to 10-20 gr salt daily. This shows that the problem of the elimination of iodine deficiency is being vigorously tackled. Since 1956 the iodine in salt in Macedonia rose to 10 m gr KI/Kg salt. The content of iodine in the Macedonian diet seems to be important. The amount of iodine in milk, eggs and bread is low as found by the investigation of MANU. The content of iodine in meat is low, compared to British meat is 10 times lower. The average iodine content in Macedonian meat is 95.15 micro gr per Kg, whereas in British meat it is 850-1510 micro gr iodine per k gr meat. (Original)

  15. Controversies in urinary iodine determinations

    OpenAIRE

    Soldin, Offie Porat

    2002-01-01

    Iodine deficiency (ID) is associated with increased prevalence of goiter, increased risk for neurodevelopmental disorders, and is the world’s leading cause of intellectual deficits. Iodine nutritional status of a population is assessed by measurements of urinary iodine concentrations which are also used to define, indicate, survey and monitor iodine deficiency and consequently its treatment. Several methods are available for urinary iodine determination. Discussed here are some of the limitat...

  16. Study of molecular iodine-epoxy paint mass transfer

    Energy Technology Data Exchange (ETDEWEB)

    Belval-Haltier, E [Inst. de Protection et Surete Nucleaire, IPSN, CEN Cadarache, St. Paul-lez-Durance (France)

    1996-12-01

    The mass transfer phenomena may have a significant influence on the quantity of I{sub 2} which could be released following a severe accident of a nuclear power plant and specially the mass transfer of iodine onto containment surfaces. So, the objective of the present work was to evaluate which phase limited the adsorption process of iodine onto gaseous epoxy paint under a range of conditions which may be relevant to a severe reactor accident. In this aim, a series of experiments was conducted in which the sorption kinetics of molecular iodine, labelled with {sup 131}I, was measured by monitoring continuously the accumulation of this species on the epoxy surface. For each test condition, the initial deposition velocity was determined and the corresponding gas phase mass transfer, kg, was estimated by using the heat transfer analogy for a laminar flow passing over a flat plate. Then, the surface reaction rate, Kr, was deduced from these two values. Experiments performed indicated that iodine adsorption onto epoxy paint is highly dependent on temperature, relative humidity of the carrier gas and moisture content of the painted coupon. In dry air flow conditions, the adsorption of iodine onto paint was found to increase with temperature and to be limited by the surface reaction rate, Kr. The I{sub 2} adsorption rate was found to increase with the humidity of carrier gas and in some studied conditions, the initial deposition velocity appeared to be controlled by gas phase mass transfer rather than surface interaction. The same phenomenon has been observed with an increase of the initial water content of the painted coupon. (author) 6 figs., 1 tab., 8 refs.

  17. Iodine Hall Thruster

    Science.gov (United States)

    Szabo, James

    2015-01-01

    Iodine enables dramatic mass and cost savings for lunar and Mars cargo missions, including Earth escape and near-Earth space maneuvers. The demonstrated throttling ability of iodine is important for a singular thruster that might be called upon to propel a spacecraft from Earth to Mars or Venus. The ability to throttle efficiently is even more important for missions beyond Mars. In the Phase I project, Busek Company, Inc., tested an existing Hall thruster, the BHT-8000, on iodine propellant. The thruster was fed by a high-flow iodine feed system and supported by an existing Busek hollow cathode flowing xenon gas. The Phase I propellant feed system was evolved from a previously demonstrated laboratory feed system. Throttling of the thruster between 2 and 11 kW at 200 to 600 V was demonstrated. Testing showed that the efficiency of iodine fueled BHT-8000 is the same as with xenon, with iodine delivering a slightly higher thrust-to-power (T/P) ratio. In Phase II, a complete iodine-fueled system was developed, including the thruster, hollow cathode, and iodine propellant feed system. The nominal power of the Phase II system is 8 kW; however, it can be deeply throttled as well as clustered to much higher power levels. The technology also can be scaled to greater than 100 kW per thruster to support megawatt-class missions. The target thruster efficiency for the full-scale system is 65 percent at high specific impulse (Isp) (approximately 3,000 s) and 60 percent at high thrust (Isp approximately 2,000 s).

  18. Iodine deficiency and thyroid disorders.

    Science.gov (United States)

    Zimmermann, Michael B; Boelaert, Kristien

    2015-04-01

    Iodine deficiency early in life impairs cognition and growth, but iodine status is also a key determinant of thyroid disorders in adults. Severe iodine deficiency causes goitre and hypothyroidism because, despite an increase in thyroid activity to maximise iodine uptake and recycling in this setting, iodine concentrations are still too low to enable production of thyroid hormone. In mild-to-moderate iodine deficiency, increased thyroid activity can compensate for low iodine intake and maintain euthyroidism in most individuals, but at a price: chronic thyroid stimulation results in an increase in the prevalence of toxic nodular goitre and hyperthyroidism in populations. This high prevalence of nodular autonomy usually results in a further increase in the prevalence of hyperthyroidism if iodine intake is subsequently increased by salt iodisation. However, this increase is transient because iodine sufficiency normalises thyroid activity which, in the long term, reduces nodular autonomy. Increased iodine intake in an iodine-deficient population is associated with a small increase in the prevalence of subclinical hypothyroidism and thyroid autoimmunity; whether these increases are also transient is unclear. Variations in population iodine intake do not affect risk for Graves' disease or thyroid cancer, but correction of iodine deficiency might shift thyroid cancer subtypes toward less malignant forms. Thus, optimisation of population iodine intake is an important component of preventive health care to reduce the prevalence of thyroid disorders. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Adsorption of methyl iodide on charcoal

    International Nuclear Information System (INIS)

    Hidajat, K.; Aracil, J.; Kenney, C.N.

    1990-01-01

    The adsorption of non-radioactive methyl iodide has been measured experimentally over a range of conditions of concentration, and temperature on an activated charcoal. This is of interest since methyl iodide is formed from iodine fission products in gas cooled nuclear reactors. A mathematical model has also been developed which describes the rate of adsorption, under isothermal and linear adsorption isotherm conditions in a recycle adsorber. This model takes into account the resistance to adsorption caused by the surface adsorption, as well as the external and internal mass transfer resistances. The solution to the model for the recycle adsorber was obtained using a semidiscretisation method to reduce the partial differential equations to a system of stiff ordinary differential equations, and the resulting differential equations solved by a standard numerical technique. (author)

  20. Determination of iodine 129 in vegetables using neutron activation analysis

    International Nuclear Information System (INIS)

    Quintana, Eduardo E.; Thyssen, Sandra M.; Bruno, Hector A.

    1999-01-01

    The developed methodology allows the determination of iodine 129 in vegetables, using neutron activation analysis. The chemical treatment removes the interferences present in these matrixes, as well as the bromine 82 originated in the activation process. The experimental method for the determination of iodine 129 by neutron activation analysis involves five steps: 1- digestion by alkaline fusion; 2- pre-irradiation purification of iodine 129 by distillation followed by solvent extraction, and adsorption on activated charcoal by distillation; 3- neutron irradiation; 4- post-irradiation purification of iodine 130 by distillation followed by solvent extraction; 5- gamma spectrometry. A chemical recovery of 95 % is obtained in the distillations, measured using iodine 131 as tracer. The whole process recovery is within 70 % and 85 %. The detection limit is 2 mBq/kg of sample, but several factors affect this value, such as type of vegetable, natural iodine concentration, irradiation time and neutron flux. The methodology developed is applied at environmental surveillance with safeguards proposes, in the detection of undeclared reprocessing of irradiated fuel. (authors)

  1. Dissociation in small molecules

    International Nuclear Information System (INIS)

    Dehmer, P.M.

    1982-01-01

    The study of molecular dissociation processes is one of the most interesting areas of modern spectroscopy owing to the challenges presented bt even the simplest of diatomic molecules. This paper reviews the commonly used descriptions of molecular dissociation processes for diatomic molecules, the selection rules for predissociation, and a few of the principles to be remembered when one is forced to speculate about dissociation mechanisms in a new molecule. Some of these points will be illustrated by the example of dissociative ionization in O 2

  2. Estimation of spin contamination error in dissociative adsorption of Au2 onto MgO(0 0 1) surface: First application of approximate spin projection (AP) method to plane wave basis

    Science.gov (United States)

    Tada, Kohei; Koga, Hiroaki; Okumura, Mitsutaka; Tanaka, Shingo

    2018-06-01

    Spin contamination error in the total energy of the Au2/MgO system was estimated using the density functional theory/plane-wave scheme and approximate spin projection methods. This is the first investigation in which the errors in chemical phenomena on a periodic surface are estimated. The spin contamination error of the system was 0.06 eV. This value is smaller than that of the dissociation of Au2 in the gas phase (0.10 eV). This is because of the destabilization of the singlet spin state due to the weakening of the Au-Au interaction caused by the Au-MgO interaction.

  3. Efforts to Consolidate Chalcogels with Adsorbed Iodine

    Energy Technology Data Exchange (ETDEWEB)

    Riley, Brian J.; Pierce, David A.; Chun, Jaehun

    2013-08-28

    This document discusses ongoing work with non-oxide aerogels, called chalcogels, that are under development at the Pacific Northwest National Laboratory as sorbents for gaseous iodine. Work was conducted in fiscal year 2012 to demonstrate the feasibility of converting Sn2S3 chalcogel without iodine into a glass. This current document summarizes the work conducted in fiscal year 2013 to assess the consolidation potential of non-oxide aerogels with adsorbed iodine. The Sn2S3 and Sb13.5Sn5S20 chalcogels were selected for study. The first step in the process for these experiments was to load them with iodine (I2). The I2 uptake was ~68 mass% for Sn2S3 and ~50 mass% for Sb13.5Sn5S20 chalcogels. X-ray diffraction (XRD) of both sets of sorbents showed that metal-iodide complexes were formed during adsorption, i.e., SnI4 for Sn2S3 and SbI3 for Sb13.5Sn5S20. Additionally, metal-sulfide-iodide complexes were formed, i.e., SnSI for Sn2S3 and SbSI for Sb13.5Sn5S20. No XRD evidence for unreacted iodine was found in any of these samples. Once the chalcogels had reached maximum adsorption, the consolidation potential was assessed. Here, the sorbents were heated for consolidation in vacuum-sealed quartz vessels. The Sb13.5Sn5S20 chalcogel was heated both (1) in a glassy carbon crucible within a fused quartz tube and (2) in a single-containment fused quartz tube. The Sn2S3 chalcogel was only heated in a single-containment fused quartz tube. In both cases with the single-containment fused quartz experiments, the material consolidated nicely. However, in both cases, there were small fractions of metal iodides not incorporated into the final product as well as fused quartz particles within the melt due to the sample attacking the quartz wall during the heat treatment. The Sb13.5Sn5S20 did not appear to attack the glassy carbon crucible so, for future experiments, it would be ideal to apply a coating, such as pyrolytic graphite, to the inner walls of the fused quartz vessel to prevent

  4. Volatilization of iodine from vegetation

    International Nuclear Information System (INIS)

    Amiro, B.D.; Johnston, F.L.

    1989-01-01

    Gaseous emissions of iodine were measured from bean plant foliage. A gamma-emitting iodine tracer, Na 125 I, was taken up by the plants from a hydroponic growth medium and released to a cuvette atmosphere. The dynamics of the flux were studied using a flow-through gamma detector. The relationship between leaf radioactive tracer activity and growth-medium activity was linear, as was the relationship between the iodine flux and both leaf and growth-medium activity. Iodine flux and leaf conductance to water responded similarly to changes in light levels, suggesting that the stomata may partially control the flux. The flux was inhibited by aeration of the hydroponic growth media, and we postulate that methylation causes the iodine flux. Iodine emissions from living vegetation probably contribute < 0.1% to the stable iodine concentration in the atmosphere above terrestrial areas. However, this pathway may be a direct route for radioactive iodine transport from contaminated soils to the atmosphere. (author)

  5. Radioactive iodine intake through foodstuff

    International Nuclear Information System (INIS)

    Omomo, Yoichiro

    1974-01-01

    The transition of radioactive iodine to human bodies is affected by the amount of coexisting stable iodine. The intake of stable iodine through foodstuffs was studied from the stand point of I) discussion of the literature which states the approximate amounts of stable iodine contained in environmental materials, and II) the authors' research on the consumption of foodstuffs. For example, the amounts of iodine intake of fishermen living in Kuji-cho (Ibaragi Prefecture) was estimated from I and II, and was revealed as 2704p. The national average iodine intake was about 800p indicating that the former estimated value was remarkably high. Eighty Four per cent of the 2.7 mg iodine intake was taken from marine products, indicating that marine products are important sources of iodine supply. (Tsukamoto, Y.)

  6. Catalytic methanol dissociation

    International Nuclear Information System (INIS)

    Alcinikov, Y.; Fainberg, V.; Garbar, A.; Gutman, M.; Hetsroni, G.; Shindler, Y.; Tatrtakovsky, L.; Zvirin, Y.

    1998-01-01

    Results of the methanol dissociation study on copper/potassium catalyst with alumina support at various temperatures are presented. The following gaseous and liquid products at. The catalytic methanol dissociation is obtained: hydrogen, carbon monoxide, carbon dioxide, methane, and dimethyl ether. Formation rates of these products are discussed. Activation energies of corresponding reactions are calculated

  7. Dissociation in mediation

    Directory of Open Access Journals (Sweden)

    Daniela Muraru

    2008-01-01

    Full Text Available This paper approaches several texts that are part of the so-called discourse of mediation, adopting a pragma-dialectical perspective of the theory of dissociation. It is an attempt to identify the uses of dissociative patterns, with special emphasis on the indicators of dissociation. The paper investigates the various uses of the concept of dissociation as a discursive technique in the argumentation on the different aspects that are involved in international conflict, such as the discussion of the notion of peace. The purpose is to identify the role of dissociation, as a device strategically used by the mediator to help the parties minimize the disagreement space, and come to a conflict resolution.

  8. Highly efficient capture of iodine by Cu/MIL-101

    Science.gov (United States)

    Qi, Bingbing; Liu, Ying; Zheng, Tao; Gao, Qianhong; Yan, Xuewu; Jiao, Yan; Yang, Yi

    2018-02-01

    In order to improve the uptake capacity of MIL-101 for iodine, Cu nanoparticles doped MIL-101 were successfully synthesized through a facile method. The obtained Cu/MIL-101 was characterized by SEM, XRD, EDS, TEM, IR, TGA and BET to examine the chemical and thermal stabilities. The capture experiments for the adsorbents showed that the capture capacity of Cu/MIL-101 for volatile iodine is 342 wt%, which is higher than that of pure MIL-101. An I2 uptake of 342 wt% is the highest value reported among metal-organic frameworks. Furthermore, Cu/MIL-101 has a cycle ratio of 95% after three cycles and exhibits a better cyclicity than pure MIL-101. Meanwhile, Cu/MIL-101 shows an excellent reversible adsorption of iodine in solution.

  9. Mock iodine-125 radiation source

    International Nuclear Information System (INIS)

    Coffey, D.L.

    1976-01-01

    An intimate mixture of americium-241 and iodine-129 provides an energy spectrum that reliably simulates the spectrum of iodine-125 in a well-type detector. As such, it may be used as a long-lived standard to calibrate instruments such as well scintillation spectrometers in which measurements are to be made involving iodine-125

  10. The retention of iodine in stainless steel sample lines

    Energy Technology Data Exchange (ETDEWEB)

    Evans, G.J.; Deir, C. [Univ. of Toronto (Canada); Ball, J.M. [Whiteshell Laboratories, Pinawa (Canada)

    1995-02-01

    Following an accident in a multi-unit CANDU nuclear generating station, decontamination of air vented from containment would play a critical role in minimizing the release of iodine to the environment. The concentration of gas phase iodine in containment air would be measured using the post accident radiation monitoring system, requiring that air samples be passed through a considerable length of tubing to a remote location where the desired measurements could safely be made. A significant loss of iodine, due to adsorption on the sample line surfaces, could greatly distort the measurement. In this study, the retention of I{sub 2}(g) on stainless steel was evaluated in bench scale experiments in order to evaluate, and if possible minimise, the extent of any such line losses. Experiments at the University of Toronto were performed using 6 inch lengths of 1/4 inch stainless steel tubing. Air, containing I-131 labelled I{sub 2}(g), ranging in concentration from 10{sup {minus}10} to 10{sup {minus}6} mol/dm{sup 3} and relative humidity (:RH) from 20 to 90 %, was passed through tubing samples maintained at temperatures ranging from 25 to 90{degrees}C. Adsorption at low gas phase iodine concentrations differed substantially from that at higher concentrations. The rate of deposition was proportional to the gas phase concentration, giving support to the concept of a first order deposition velocity. The surface loading increased with increasing relative humidity, particularly at low RH values, while the deposition rate decreased with increasing temperature. Surface water on the steel may play an important role in the deposition process. The chemisorbed iodine was located primarily in areas of corrosion. Furthermore, water used to wash the steel contained Fe, Mn and iodine in the form of iodide, suggesting that I{sub 2} reacted to form metal iodides. The deposition of I{sub 2} was also found to depend on the initial surface condition.

  11. When Langmuir is too simple: H-2 dissociation on Pd(111) at high coverage

    DEFF Research Database (Denmark)

    Lopez, Nuria; Lodziana, Zbigniew; Illas, F.

    2004-01-01

    Recent experiments of H-2 adsorption on Pd(111) [T. Mitsui et al., Nature (London) 422, 705 (2003)] have questioned the classical Langmuir picture of second order adsorption kinetics at high surface coverage requiring pairs of empty sites for the dissociative chemisorption. Experiments find that ...

  12. Acidic gases (CO_2, NO_2 and SO_2) capture and dissociation on metal decorated phosphorene

    International Nuclear Information System (INIS)

    Kuang, Anlong; Kuang, Minquan; Yuan, Hongkuan; Wang, Guangzhao; Chen, Hong; Yang, Xiaolan

    2017-01-01

    Highlights: • The light metal decorated phosphorene sheets are very effective for capture of CO_2, NO_2 and SO_2 because of large adsorption energies. • The adsorption energy is obviously dependent on the amount of electrons transferred between acidic gases and metal decorated phosphorene. • Pt-decorated phosphorene can effectively catalyze the dissociation of acidic gas. - Abstract: Density functional theory is employed to investigate the adsorption and dissociation of several acidic gases (CO_2, NO_2 and SO_2) on metal (Li, Al, Ni and Pt) decorated phosphorene. The results show that light metal (Li, Al) decorated phosphorene exhibits a strong adsorption of acidic gases, i.e., the adsorption energy of CO_2 on Li decorated phosphorene is 0.376 eV which is the largest in all adsorption of CO_2 on metal decorated phosphorene and Al decorated phosphorene is most effective for capture of NO_2 and SO_2 due to large adsorption energies of 3.951 and 3.608 eV, respectively. Moreover, Li and Al light metals have stronger economic effectiveness and more friendly environment compared with the transition metals, the strong adsorption ability of acidic gases and low price suggest that Li, Al decorated phosphorene may be useful and promising for collection and filtration of exhaust gases. The reaction energy barriers of acidic gases dissociated process on Pt decorated phosphorene are relatively low and the reaction processes are significantly exothermic, indicating that the dissociation process is favorable.

  13. Chromatographic separation of Iodine species for environmental studies

    Energy Technology Data Exchange (ETDEWEB)

    Machado, E.C. [Universidade Federal Fluminense, Niteroi, RJ (Brazil). Dept. de Geoquimica]. E-mail: geoedin@vm.uff.br; Bellido, A.V.B. [Universidade Federal Fluminense, Niteroi, RJ (Brazil). Dept. de Fisico-Quimica]. E-mail: alf@risc2.rmn.uff.br; Bellido, L.F. [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil)]. E-mail: lbellido@cnen.gov.br

    1999-07-01

    In this work a experimental method was developed to separate iodine species from environmental samples by using adsorption chromatography. The radionuclide {sup 123} I which has a half-life of 13 h and a convenient gamma ray of 159 keV was used to investigate a fast and efficient procedure for the separation of iodide and iodate ions in seawater from mangrove samples. The radio-iodine tracer technique is very useful, particularly in kinetic studies because it is easy to detect without any interference of concentration due to the small amount of tracer that is spiked. It is also possible to add two tracers (I-123 and I-131) in different oxidation states. Three chromatographic methods were studied: paper, thin layer and adsorption chromatography with silica and alumina. It was found that paper chromatography is very useful for checking the valence adjustment of the radioiodine species. Initially, several coefficient distributions of iodine species by adsorption in silica and alumina from NaOH, NaHCO{sub 3} and NaNO{sub 3} solutions (in the range 05. - 0.0001 m) were determined. The best separation so far was achieved by loading the sample (after adjusting the concentration to 0.1 NNaNO{sub 3}) into a chromatographic column with Al{sub 2} O{sub 3}. The iodide passes through the column and after washing the column, the iodate was removed by eluting with 1.0 M NaHCO{sub 3} solution. (author)

  14. Chromatographic separation of Iodine species for environmental studies

    International Nuclear Information System (INIS)

    Machado, E.C.

    1999-01-01

    In this work a experimental method was developed to separate iodine species from environmental samples by using adsorption chromatography. The radionuclide 123 I which has a half-life of 13 h and a convenient gamma ray of 159 keV was used to investigate a fast and efficient procedure for the separation of iodide and iodate ions in seawater from mangrove samples. The radio-iodine tracer technique is very useful, particularly in kinetic studies because it is easy to detect without any interference of concentration due to the small amount of tracer that is spiked. It is also possible to add two tracers (I-123 and I-131) in different oxidation states. Three chromatographic methods were studied: paper, thin layer and adsorption chromatography with silica and alumina. It was found that paper chromatography is very useful for checking the valence adjustment of the radioiodine species. Initially, several coefficient distributions of iodine species by adsorption in silica and alumina from NaOH, NaHCO 3 and NaNO 3 solutions (in the range 05. - 0.0001 m) were determined. The best separation so far was achieved by loading the sample (after adjusting the concentration to 0.1 NNaNO 3 ) into a chromatographic column with Al 2 O 3 . The iodide passes through the column and after washing the column, the iodate was removed by eluting with 1.0 M NaHCO 3 solution. (author)

  15. Iodine in soil

    International Nuclear Information System (INIS)

    Johanson, Karl Johan

    2000-12-01

    A literature study of the migration and the appearance of iodine isotopes in the bio-sphere particularly in soil is presented. Some important papers in the field of iodine appearance in soil and the appearance of 129 I in the surroundings of reprocessing plants are discussed. The most important conclusions are: 1. Iodine binds to organic matter in the soil and also to some oxides of aluminium and iron. 2. If the iodine is not bound to the soil a large fraction of added 129 I is volatilized after a rather short period. 3. The binding and also the volatilisation seems to be due to biological activity in the soil. It may take place within living microorganisms or by external enzymes excreted from microorganisms. 4. Due to variations in the composition of soil there may be a large variation in the distribution of 129 I in the vertical profile of soil - usually most of the 129 I in the upper layer - which also results in large variations in the 129 I uptake to plants

  16. Iodine in soil

    Energy Technology Data Exchange (ETDEWEB)

    Johanson, Karl Johan [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Forest Mycology and Pathology

    2000-12-01

    A literature study of the migration and the appearance of iodine isotopes in the bio-sphere particularly in soil is presented. Some important papers in the field of iodine appearance in soil and the appearance of {sup 129}I in the surroundings of reprocessing plants are discussed. The most important conclusions are: 1. Iodine binds to organic matter in the soil and also to some oxides of aluminium and iron. 2. If the iodine is not bound to the soil a large fraction of added {sup 129}I is volatilized after a rather short period. 3. The binding and also the volatilisation seems to be due to biological activity in the soil. It may take place within living microorganisms or by external enzymes excreted from microorganisms. 4. Due to variations in the composition of soil there may be a large variation in the distribution of {sup 129}I in the vertical profile of soil - usually most of the {sup 129}I in the upper layer - which also results in large variations in the {sup 129}I uptake to plants.

  17. Iodine filters in nuclear installations

    International Nuclear Information System (INIS)

    Wilhelm, J.G.

    1982-01-01

    The present report discusses the significance for environmental exposure of the iodine released with the gaseous effluents of nuclear power stations and reprocessing plants in relation to releases of other airborne radionuclides. Iodine filtration processes are described. The release pathways and the composition of airborne fission product iodine mixtures and their bearing on environmental exposure are discussed on the basis of measured fission product iodine emissions. The sorbents which can be used for iodine filtration, their removal efficiencies and range of applications are dealt with in detail. The particular conditions governing iodine removal, which are determined by the various gaseous iodine species, are illustrated on the basis of experimentally determined retention profiles. Particular attention is given to the limitations imposed by temperature, humidity, radiation and filter poisoning. The types of filter normally used are described, their advantages and drawbacks discussed, the principles underlying their design are outlined and the sources of error indicated. The methods normally applied to test the efficiency of various iodine sorbents are described and assessed. Operating experience with iodine filters, gathered from surveillance periods of many years, is supplemented by a large number of test results and the findings of extensive experiments. Possible ways of prolonging the permissible service lives of iodine filters are discussed and information is given on protective measures. The various iodine removal processes applied in reprocessing plants are described and compared with reference to efficiency and cost. The latest developments in filter technology in reprocessing plants are briefly outlined

  18. A first-principles study of Pt–Ni bimetallic cluster adsorption on the anatase TiO{sub 2} (1 0 1) surface: Probing electron effect of Ni in TiO{sub 2} (1 0 1)-bimetallic cluster (Pt–Ni) on the adsorption and dissociation of methanol

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Feila, E-mail: liufeila@u.washington.edu [College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China); Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195 (United States); Xiao, Peng, E-mail: xiaopeng@cqu.edu.cn [College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China); Uchaker, Evan, E-mail: uchaker@u.washington.edu [Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195 (United States); He, Huichao, E-mail: hehuichao985@gmail.com [College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China); Zhou, Ming, E-mail: Zhoumingcqu2007@163.com [College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China); Zhou, Xin, E-mail: zhoux@hit.edu.cn [State Key Laboratory of Urban Water Resource and Environment, Institute of Theoretical and Simulation Chemistry, Academy of Fundamental and Interdisciplinary Sciences, Harbin Institute of Technology, Harbin 150080 (China); Zhang, Yunhuai, E-mail: xp2031@163.com [College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China)

    2014-10-01

    Graphical abstract: - Highlights: • Condensed Fukui function is used to predict the regioselectivity of clusters. • Pt–Ni alloy and TiO{sub 2} can effectively oxidize methanol compared with pure Pt. • The methanol dehydrogenation over Pt{sub 3}Ni/TiO{sub 2} is an optimal reaction pathway. • The alloying of Ni can effectively alleviate CO poisoning. - Abstract: A density functional theory (DFT) based method in conjunction with the projector augmented wave and pseudopotential methods have been applied to investigate the adsorption of Pt{sub 4} and Pt{sub 3}Ni on the anatase TiO{sub 2} (1 0 1) surface. Two stable Pt{sub 3}Ni adsorptions with considerable adsorption energies on the anatase TiO{sub 2} (1 0 1) surface were identified. Analysis of the partial density (PDOS) of states and Bader charge suggest that the electronic structure of Pt is modified by Ni due to the electron transfer from Ni to Pt atoms in the Pt{sub 3}Ni clusters. The 2cO (3cO)-PtNi-5cTi conformation of the adsorbed Pt{sub 3}Ni on the anatase TiO{sub 2} (1 0 1) surface provides a more feasible model for electron injection through the Pt{sub 3}Ni/TiO{sub 2} interface. The reactivity of Pt{sub 3}Ni/TiO{sub 2} is superior to Pt{sub 4}/TiO{sub 2} and effectively manifests itself in the eased decomposition of O-H bonds derived by methanol and alleviative CO adsorption.

  19. Perchlorate, iodine supplements, iodized salt and breast milk iodine content

    Energy Technology Data Exchange (ETDEWEB)

    Kirk, Andrea B. [Department of Epidemiology, School of Public Health, University of North Texas Health Sciences Center, 3500 Camp Bowie Blvd., Fort Worth, TX 76107 (United States); Kroll, Martina; Dyke, Jason V.; Ohira, Shin-Ichi; Dias, Rukshan A.; Dasgupta, Purnendu K. [Department of Chemistry and Biochemistry, 700 Planetarium Place, University of Texas at Arlington, Arlington, TX 76019 (United States)

    2012-03-15

    This study was undertaken to determine if increasing maternal iodine intake through single dose tablets will decrease breast milk concentrations of the iodine-uptake inhibitor, perchlorate, through competitive inhibition. We also sought to determine if the timing of supplementation influences the fraction of iodine excreted in milk versus urine and to compare the effectiveness of iodized salt as a means of providing iodine to breastfed infants. Thirteen women who did not use supplements, seven of whom used iodized salt and six of whom used non-iodized salt, submitted four milk samples and a 24-h urine collection daily for three days. Women repeated the sampling protocol for three more days during which {approx} 150 {mu}g of iodine were taken in the evening and again for three days with morning supplementation. Samples were analyzed using isotope-dilution inductively-coupled plasma-mass spectrometry for iodine and isotope-dilution ion chromatography-tandem mass spectrometry for perchlorate. No statistically significant differences were observed in milk iodine or perchlorate concentrations during the two treatment periods. Estimated perchlorate intake was above the U.S. National Academy of Sciences suggested reference dose for most infants. Single daily dose iodine supplementation was not effective in decreasing milk perchlorate concentrations. Users of iodized salt had significantly higher iodine levels in milk than non-users. Iodized salt may be a more effective means of iodine supplementation than tablets. - Highlights: Black-Right-Pointing-Pointer Estimated infant exposures to perchlorate were, on a {mu}g/kg basis, {approx} 5 Multiplication-Sign higher than those of mothers. Black-Right-Pointing-Pointer Daily supplements are less effective than iodized salt in providing iodine to lactating women. Black-Right-Pointing-Pointer Low iodine and high perchlorate in milk may place infants at risk of iodine deficiency.

  20. Heterogeneous equilibrium in mplybdenum-iodine system

    International Nuclear Information System (INIS)

    Klinkova, L.A.

    1983-01-01

    Heterogeneous equilibrium in the Mo-J system is studied to reveal regions of existence of molybdenum iodides, is studied. The investigation is performed for atomic ratio I/Mo=0.02-7.5 in the temperature range of 300-1370 K using methods of thermographic, X-ray phase, chemical and optical analyses of phases quenched after isothermal annealing. It is shown that higher molybdenum iodides (Mo1 4 , MoJ 5 , MoJ 6 ) are thermally unstable compounds and exist in the Mo-J system at low temperatures (360-490 K). Above 470 K higher iodides dissociate up to molybdenum triiodide. MoJ 3 under the pressure of iodine vapors is stable up to 970 K. Molybdenum diiodide is the product of triiodide decomposition and forms in the Mo-J system in the 700-1270 K range. At the J/Mo>>3 ratio the product of triiodide decomposition is MoJsub(2.87) which is thermally unstable up to 570 K, while in iodine atmosphere - up to 1170 K

  1. Iodine Status in Pregnant & Breastfeeding Women

    DEFF Research Database (Denmark)

    Andersen, Stine Linding

    Iodine is required for the synthesis of thyroid hormones, which are crucial regulator of early brain development. The source of iodine in the fetus and the breastfed infant is maternal iodine, and adequate iodine intake in pregnant and breastfeeding is of major concern. Severe iodine deficiency can...... cause irreversible brain damage, whereas the consequences of mild to moderate iodine deficiency are less clear. Denmark was previously iodine deficient with regional differences (mild iodine deficiency in East Denmark and moderate iodine deficiency in West Denmark), and also pregnant and breastfeeding...... women suffered from iodine deficiency. A mandatory iodine fortification of household salt and salt used for commercial production of bread was introduced in Denmark in the year 2000. The PhD thesis investigates intake of iodine supplements and urinary iodine status in Danish pregnant and breastfeeding...

  2. The behaviour of radionuclides in gas adsorption chromatographic processes with superimposed chemical reactions (chlorides)

    International Nuclear Information System (INIS)

    Eichler, B.

    1996-01-01

    Thermochemical relationships are derived describing the gas adsorption chromatographic transport of carrier-free radionuclides. Especially, complex adsorption processes such as dissociative, associative and substitutive adsorption are dealt with. The comparison of experimental with calculated data allows the determination of the type of adsorption reaction, which is the basis of the respective gas chromatographic process. The behaviour of carrier-free radionuclides of elements Pu, Ce, Ru, Co and Cr in thermochromatographic experiments with chlorinating carrier gases can be described as dissociative adsorption of chlorides in higher oxidation states. The gas adsorption chromatographic transport of Zr with oxygen and chlorine containing carrier gas is shown to be a substitutive adsorption process. The consequences of superimposed chemical reactions on the interpretation of results and the conception of gas adsorption chromatographic experiments with carrier-free radionuclides in isothermal columns and in temperature gradient tubes is discussed. (orig.)

  3. The speciation of iodine in the environment

    International Nuclear Information System (INIS)

    Bulman, R.A.

    1986-01-01

    The speciation of iodine in the environment is discussed under the following topics: (i) sea surface to atmosphere, (ii) chemistry in bulk seawater, (iii) iodine in rocks, (iv) iodine in soils, (v) iodine in plants and (vi) iodine in solidified wastes. (author)

  4. The iodine molecule insights into intra- and intermolecular perturbation in diatomic molecules

    CERN Document Server

    Lukashov, Sergey; Pravilov, Anatoly

    2018-01-01

    This book presents experimental and theoretical spectroscopic studies performed over the last 25 years on the iodine molecule’s excited states and their perturbations. It is going to be of interest to researchers who study intra- and intermolecular perturbations in diatomic molecules and more complex systems. The book offers a detailed treatment of the nonadiabatic perturbations of valence, ion pair and Rydberg states induced by intramolecular as well as intermolecular interactions in collisions or in weakly-bound complexes. It also provides an overview of current instrumentation and techniques as well as theoretical approaches describing intra- and intermolecular perturbations. The authors are experts in the use of spectroscopy for the study of intrinsic and collision-induced perturbations in diatomic iodine. They introduced new methods of two- and three-step optical population of the iodine ion-pair states. The iodine molecule has 23 valence states correlating with three dissociation limits, 20 so-called ...

  5. FY-2015 Methyl Iodide Deep-Bed Adsorption Test Report

    Energy Technology Data Exchange (ETDEWEB)

    Soelberg, Nicholas Ray [Idaho National Lab. (INL), Idaho Falls, ID (United States); Watson, Tony Leroy [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-09-30

    Nuclear fission produces fission and activation products, including iodine-129, which could evolve into used fuel reprocessing facility off-gas systems, and could require off-gas control to limit air emissions to levels within acceptable emission limits. Deep-bed methyl iodide adsorption testing has continued in Fiscal Year 2015 according to a multi-laboratory methyl iodide adsorption test plan. Updates to the deep-bed test system have also been performed to enable the inclusion of evaporated HNO3 and increased NO2 concentrations in future tests. This report summarizes the result of those activities. Test results showed that iodine adsorption from gaseous methyl iodide using reduced silver zeolite (AgZ) resulted in initial iodine decontamination factors (DFs, ratios of uncontrolled and controlled total iodine levels) under 1,000 for the conditions of the long-duration test performed this year (45 ppm CH3I, 1,000 ppm each NO and NO2, very low H2O levels [3 ppm] in balance air). The mass transfer zone depth exceeded the cumulative 5-inch depth of 4 bed segments, which is deeper than the 2-4 inch depth estimated for the mass transfer zone for adsorbing I2 using AgZ in prior deep-bed tests. The maximum iodine adsorption capacity for the AgZ under the conditions of this test was 6.2% (6.2 g adsorbed I per 100 g sorbent). The maximum Ag utilization was 51%. Additional deep-bed testing and analyses are recommended to (a) expand the data base for methyl iodide adsorption and (b) provide more data for evaluating organic iodide reactions and reaction byproducts for different potential adsorption conditions.

  6. FY-2015 Methyl Iodide Deep-Bed Adsorption Test Report

    International Nuclear Information System (INIS)

    Soelberg, Nicholas Ray; Watson, Tony Leroy

    2015-01-01

    Nuclear fission produces fission and activation products, including iodine-129, which could evolve into used fuel reprocessing facility off-gas systems, and could require off-gas control to limit air emissions to levels within acceptable emission limits. Deep-bed methyl iodide adsorption testing has continued in Fiscal Year 2015 according to a multi-laboratory methyl iodide adsorption test plan. Updates to the deep-bed test system have also been performed to enable the inclusion of evaporated HNO 3 and increased NO 2 concentrations in future tests. This report summarizes the result of those activities. Test results showed that iodine adsorption from gaseous methyl iodide using reduced silver zeolite (AgZ) resulted in initial iodine decontamination factors (DFs, ratios of uncontrolled and controlled total iodine levels) under 1,000 for the conditions of the long-duration test performed this year (45 ppm CH3I, 1,000 ppm each NO and NO 2 , very low H 2 O levels [3 ppm] in balance air). The mass transfer zone depth exceeded the cumulative 5-inch depth of 4 bed segments, which is deeper than the 2-4 inch depth estimated for the mass transfer zone for adsorbing I 2 using AgZ in prior deep-bed tests. The maximum iodine adsorption capacity for the AgZ under the conditions of this test was 6.2% (6.2 g adsorbed I per 100 g sorbent). The maximum Ag utilization was 51%. Additional deep-bed testing and analyses are recommended to (a) expand the data base for methyl iodide adsorption and (b) provide more data for evaluating organic iodide reactions and reaction byproducts for different potential adsorption conditions.

  7. Disposal of Iodine-129

    International Nuclear Information System (INIS)

    Morgan, M.T.; Moore, J.G.; Devaney, H.E.; Rogers, G.C.; Williams, C.; Newman, E.

    1978-01-01

    One of the problems to be solved in the nuclear waste management field is the disposal of radioactive iodine-129, which is one of the more volatile and long-lived fission products. Studies have shown that fission products can be fixed in concrete for permanent disposal. Current studies have demonstrated that practical cementitious grouts may contain up to 18% iodine as barium iodate. The waste disposal criterion is based on the fact that harmful effects to present or future generations can be avoided by isolation and/or dilution. Long-term isolation is effective in deep, dry repositories; however, since penetration by water is possible, although unlikely, release was calculated based on leach rates into water. Further considerations have indicated that sea disposal on or in the ocean floor may be a more acceptable alternative

  8. Atomic iodine laser

    International Nuclear Information System (INIS)

    Fisk, G.A.; Gusinow, M.A.; Hays, A.K.; Padrick, T.D.; Palmer, R.E.; Rice, J.K.; Truby, F.K.; Riley, M.E.

    1978-05-01

    The atomic iodine photodissociation laser has been under intensive study for a number of years. The physics associated with this system is now well understood and it is possible to produce a 0.1 nsec (or longer) near-diffraction-limited laser pulse which can be amplified with negligible temporal distortion and little spatial deformation. The output of either a saturated or unsaturated amplifier consists of a high-fidelity near-diffraction-limited, energetic laser pulse. The report is divided into three chapters. Chapter 1 is a survey of the important areas affecting efficient laser operation and summarizes the findings of Chap. 2. Chapter 2 presents detailed discussions and evaluations pertinent to pumps, chemical regeneration, and other elements in the overall laser system. Chapter 3 briefly discusses those areas that require further work and the nature of the work required to complete the full-scale evaluation of the applicability of the iodine photodissociation laser to the inertial confinement program

  9. Hyperthyroidism and radioactive iodine

    International Nuclear Information System (INIS)

    Corstens, F.H.M.

    1980-01-01

    The study details the results of treatment of patients with hyperthyroidism using a combination of fractionated low doses radioactive iodine and anthithyroid drug therapy. The patients studied were treated according to this regimen after August 1968 and all reached euthyroidism before March 1979. None of the patients had been treated with radioactive iodine prior to the start of the protocol. A subgroup of the patients had received an unsuccessfull course with antithyroid drug therapy and, or, surgical therapy before the start of the protocol. Patients who had never been treated for hyperthyroidism were given antithyroid drug therapy for at least 6 months in an attempt to reach euthryroidism without the use of 131 I therapy. Therefore, all patients had experienced a course of unsuccessfull therapy prior to the start of the treatment protocol using combined fractionated low doses of 131 I and antithyroid drug therapy. (Auth.)

  10. Iodine immobilization in apatites

    International Nuclear Information System (INIS)

    Audubert, F.; Lartigue, J.E.

    2000-01-01

    In the context of a scientific program on long-lived radionuclide conditioning, a matrix for iodine 129 immobilization has been studied. A lead vanado-phosphate apatite was prepared from the melt of lead vanado-phosphate Pb 3 (VO 4 ) 1.6 (PO 4 ) 0.4 and lead iodide PbI 2 in stoichiometric proportions by calcination at 700 deg. C during 3 hours. Natural sintering of this apatite is not possible because the product decomposition occurs at 400 deg. C. Reactive sintering is the solution. The principle depends on the coating of lead iodide with lead vanado-phosphate. Lead vanado-phosphate coating is used as iodo-apatite reactant and as dense covering to confine iodine during synthesis. So the best condition to immobilize iodine during iodo-apatite synthesis is a reactive sintering at 700 deg. C under 25 MPa. We obtained an iodo-apatite surrounded with dense lead vanadate. Leaching behaviour of the matrix synthesized by solid-solid reaction is under progress in order to determine chemical durability, basic mechanisms of the iodo-apatite alteration and kinetic rate law. Iodo-apatite dissolution rates were pH and temperature dependent. We obtained a rate of 2.5 10 -3 g.m -2 .d -1 at 90 deg. C in initially de-ionised water. (authors)

  11. Separation and retention of iodine

    International Nuclear Information System (INIS)

    Thomas, T.R.

    1976-01-01

    Caustic and mercuric nitrate scrubbers have been used for iodine recovery from process offgas, but they exhibit low decontamination factors for organic iodide removal and produce liquid wastes that are unsuitable for final storage. The Iodox process gives high decontamination factors for both organic iodides and elemental iodine. The liquid waste can be evaporated to a solid or concentrated and fixed in cement. Efficient separation and retention of gaseous iodine species can be obtained with silver-loaded adsorbents. The waste is a dry solid easily handled and stored. Adsorbents containing cheaper metals appear to have lower iodine-loading capacities and may be unsuitable for bulk iodine removal from process offgas because of the large amounts of solid waste that would be generated. A potential method for regenerationg and recycling silver-loaded adsorbents is being evaluated. In conjunction with the regeneration, lead-exchanged zeolite is used as a secondary adsorbent for the final fixation and storage of the iodine

  12. Adsorption of phenol on metal treated by granular activated carbon

    International Nuclear Information System (INIS)

    Kang, Kwang Cheol; Kwon, Soo Han; Kim, Seung Soo; Baik, Min Hoon; Choi, Jong Won; Kim, Jin Won

    2007-01-01

    In this study, the effect of metal treatment on Granular Activated Carbon (GAC) was investigated in the context of phenol adsorption. Cobalt(II) nitrate, and zinc(II) nitrate solution were used for metal treated. The specific surface area and the pore structure were evaluated from nitrogen adsorption data at 77 K. The phenol adsorption rates onto GAC were measured by UV-Vis spectrophotometer. Iodine adsorption capacity of Co-GAC is much better then that of the GAC. The Co-GAC with mesopore is more efficient than other adsorbents for the adsorption of polymer such as methyleneblue. The adsorption capacity of reference-GAC and metal-GAC were increased in order of Co-GAC>Zn-GAC>Reference-GAC, in spite of a decrease in specific surface area which was resulted from pore blocking by metal

  13. Immobilization of iodine in concrete

    International Nuclear Information System (INIS)

    Clark, W.E.; Thompson, C.T.

    1977-01-01

    A method for immobilizing fission product radioactive iodine recovered from irradiated nuclear fuel comprises combining material comprising water, Portland cement and about 3 to 20 wt percent iodine as Ba(IO 3 ) 2 to provide a fluid mixture and allowing the fluid mixture to harden, said Ba(IO 3 ) 2 comprising said radioactive iodine. An article for solid waste disposal comprises concrete prepared by this method. 10 claims, 2 figures

  14. Effect of carbon dioxide on the rate of iodine vapor absorption by aqueous solution of sodium hydroxide

    International Nuclear Information System (INIS)

    Eguchi, Wataru; Adachi, Motonari; Miyake, Yoshikazu

    1978-01-01

    There is always carbon dioxide in the atmosphere as an impurity. Since this is an acid gas similar to iodine, each absorption rate seems to be affected by the other due to the coexistence of these two. Experiments have been conducted to clarify the absorption rate and absorption mechanism of iodine in the simultaneous absorption of iodine and carbon dioxide. Carbon dioxide coexisting with gas phases as an impurity decreases the absorption rate of iodine in the removal by washing with water of iodine mixed in the air. The first cause of this is that the diffusion coefficient of iodine in gas phase decreases with the carbon dioxide content in the gas phase. The second cause is that coexistent carbon dioxide is an acid gas, dissociates by dissolving into the absorbing solution, increases hydrogen ion concentration together with the formation of negative ions of bicarbonate and carbonate, and reduces hydroxyl ion concentration as a result. It is more important that existence of iodine has a catalytic effect to the rate of basic catalytic hydrolysis of carbon dioxide simultaneously dissolved in water phase, and accelerates this reaction rate. The mechanism of catalytic effect of iodine for the hydrolysis of carbon dioxide can not be clarified in detail only by this experiment, but the simultaneous absorption rate of iodine and carbon dioxide can be explained satisfactorily. (Wakatsuki, Y

  15. Hydrogen adsorption on bimetallic PdAu(111) surface alloys

    DEFF Research Database (Denmark)

    Takehiro, Naoki; Liu, Ping; Bergbreiter, Andreas

    2014-01-01

    The adsorption of hydrogen on structurally well defined PdAu-Pd(111) monolayer surface alloys was investigated in a combined experimental and theoretical study, aiming at a quantitative understanding of the adsorption and desorption properties of individual PdAu nanostructures. Combining...... the structural information obtained by high resolution scanning tunneling microscopy (STM), in particular on the abundance of specific adsorption ensembles at different Pd surface concentrations, with information on the adsorption properties derived from temperature programmed desorption (TPD) spectroscopy...... and high resolution electron energy loss spectroscopy (HREELS) provides conclusions on the minimum ensemble size for dissociative adsorption of hydrogen and on the adsorption energies on different sites active for adsorption. Density functional theory (DFT) based calculations give detailed insight...

  16. Iodine neutron capture therapy

    Science.gov (United States)

    Ahmed, Kazi Fariduddin

    A new technique, Iodine Neutron Capture Therapy (INCT) is proposed to treat hyperthyroidism in people. Present thyroid therapies, surgical removal and 131I treatment, result in hypothyroidism and, for 131I, involve protracted treatment times and excessive whole-body radiation doses. The new technique involves using a low energy neutron beam to convert a fraction of the natural iodine stored in the thyroid to radioactive 128I, which has a 24-minute half-life and decays by emitting 2.12-MeV beta particles. The beta particles are absorbed in and damage some thyroid tissue cells and consequently reduce the production and release of thyroid hormones to the blood stream. Treatment times and whole-body radiation doses are thus reduced substantially. This dissertation addresses the first of the several steps needed to obtain medical profession acceptance and regulatory approval to implement this therapy. As with other such programs, initial feasibility is established by performing experiments on suitable small mammals. Laboratory rats were used and their thyroids were exposed to the beta particles coming from small encapsulated amounts of 128I. Masses of 89.0 mg reagent-grade elemental iodine crystals have been activated in the ISU AGN-201 reactor to provide 0.033 mBq of 128I. This activity delivers 0.2 Gy to the thyroid gland of 300-g male rats having fresh thyroid tissue masses of ˜20 mg. Larger iodine masses are used to provide greater doses. The activated iodine is encapsulated to form a thin (0.16 cm 2/mg) patch that is then applied directly to the surgically exposed thyroid of an anesthetized rat. Direct neutron irradiation of a rat's thyroid was not possible due to its small size. Direct in-vivo exposure of the thyroid of the rat to the emitted radiation from 128I is allowed to continue for 2.5 hours (6 half-lives). Pre- and post-exposure blood samples are taken to quantify thyroid hormone levels. The serum T4 concentration is measured by radioimmunoassay at

  17. Fibrinogen adsorption on blocked surface of albumin.

    Science.gov (United States)

    Holmberg, Maria; Hou, Xiaolin

    2011-05-01

    We have investigated the adsorption of albumin and fibrinogen onto PET (polyethylene terephthalate) and glass surfaces and how pre-adsorption of albumin onto these surfaces can affect the adsorption of later added fibrinogen. For materials and devices being exposed to blood, adsorption of fibrinogen is often a non-wanted event, since fibrinogen is part of the clotting cascade and unspecific adsorption of fibrinogen can have an influence on the activation of platelets. Albumin is often used as blocking agent for avoiding unspecific protein adsorption onto surfaces in devices designed to handle biological samples, including protein solutions. It is based on the assumption that proteins adsorbs as a monolayer on surfaces and that proteins do not adsorb on top of each other. By labelling albumin and fibrinogen with two different radioactive iodine isotopes that emit gamma radiation with different energies, the adsorption of both albumin and fibrinogen has been monitored simultaneously on the same sample. Information about topography and coverage of adsorbed protein layers has been obtained using AFM (Atomic Force Microscopy) analysis in liquid. Our studies show that albumin adsorbs in a multilayer fashion on PET and that fibrinogen adsorbs on top of albumin when albumin is pre-adsorbed on the surfaces. Copyright © 2010 Elsevier B.V. All rights reserved.

  18. Iodine removal adsorbent histories, aging and regeneration

    International Nuclear Information System (INIS)

    Hunt, J.R.; Rankovic, L.; Lubbers, R.; Kovach, J.L.

    1976-01-01

    The experience of efficiency changes with life under various test conditions is described. The adsorbents were periodically removed from both standby and continuously operating systems and tested under various test methods for residual iodine adsorption efficiency. Adsorbent from several conventional ''sampler'' cartridges versus the bulk adsorbent was also tested showing deficiency in the use of cartridge type sampling. Currently required test conditions were found inadequate to follow the aging of the adsorbent because pre-equilibration of the sample acts as a regenerant and the sample is not tested in the ''as is'' condition. The most stringent test was found to be the ambient temperature, high humidity test to follow the aging of the adsorbent. Several methods were evaluated to regenerate used adsorbents; of these high temperature steaming and partial reimpregnation were found to produce adsorbents with near identical properties of freshly prepared adsorbents

  19. Radioactive Iodine (I-131) Therapy for Hyperthyroidism

    Science.gov (United States)

    ... Physician Resources Professions Site Index A-Z Radioactive Iodine (I-131) Therapy Radioiodine therapy is a nuclear ... thyroid cancer. When a small dose of radioactive iodine I-131 (an isotope of iodine that emits ...

  20. Adsorption of radioactive I2 gas onto atmospheric aerosol

    International Nuclear Information System (INIS)

    Noguchi, Hiroshi; Murata, Mikio; Suzuki, Katsumi.

    1990-01-01

    Laboratory scale experiments on the adsorption of radioactive elemental iodine (I 2 ) gas onto atmospheric aerosol showed that the adsorption reached an equilibrium state in about twelve minutes at high initial I 2 concentrations. The proportion of iodine which was adsorbed on the aerosol gradually decreased with increading initial I 2 concentration ranging over 10 -13 to 10 -9 g/cm 3 at a reaction time of 31 min but was almost constant at a reaction time of 2 min. A fraction of iodine desorbed from particulate iodine as mainly I 2 gas. An adsorption isotherm of atmospheric aerosol for I 2 gas was estimated from the experimental data of long reaction time and high I 2 concentrations. Using this adsorption isotherm, a theoretical equation, which was similar to our previous equation, was derived to explain the experimental results. A geometric mean and standard deviation of sticking probability in the equation were estimated to be 1.2 x 10 -2 and 2.7, respectively. Almost all experimental data were within ranges of calculated results considering the geometric standard deviation of sticking probability. (author)

  1. Controlling Solid–Liquid Conversion Reactions for a Highly Reversible Aqueous Zinc–Iodine Battery

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Huilin; Li, Bin; Mei, Donghai; Nie, Zimin; Shao, Yuyan; Li, Guosheng; Li, Xiaohong S.; Han, Kee Sung; Muller, Karl T.; Sprenkle, Vincent L.; Liu, Jun

    2017-10-30

    Aqueous rechargeable batteries are desirable for many energy storage applications due to their low cost and high safety. However, low capacity and short cycle life are the significant obstacles to their practical applications. Here, we demonstrate a highly reversible aqueous zinc-iodine battery using encapsulated iodine in microporous active carbon fibers (ACFs) as cathode materials through the rational control of solid-liquid conversion reactions. The experiments and density function theory (DFT) calculations were employed to investigate the effects of solvents and properties of carbon hosts, e.g. pore size, surface chemistries, on the adsorption of iodine species. The rational manipulation of the competition between the adsorption in carbon and solvation in electrolytes for iodine species is responsible for the high reversibility and cycling stability. The zinc-iodine batteries deliver a high capacity of 180 mAh g-1 at 1C and a stable cycle life over 3000 cycles with ~90% capacity retention as well as negligible self-discharge. We believe the principles for stabilizing the zinc-iodine system could provide new insight into conversion systems such as Li-S systems.

  2. Regeneration of the iodine isotope-exchange efficiency for nuclear-grade activated carbons

    International Nuclear Information System (INIS)

    Deitz, V.R.

    1985-01-01

    The removal of radioactive iodine from air flows passing through impregnated activated carbons depends on a minimum of three distinguishable reactions: (1) adsorption on the carbon networks of the activated carbons, (2) iodine isotope exchange with impregnated iodine-127, and (3) chemical combination with impregnated tertiary amines when present. When a carbon is new, all three mechanisms are at peak performance and it is not possible to distinguish among the three reactions by a single measurement; the retention of methyl iodide-127 is usually equal to the retention of methyl iodide-131. After the carbon is placed in service, the three mechanisms of iodine removal are degraded by the contaminants of the air at different rates; the adsorption process degrades faster than the other two. This behavior will be shown by comparisons of methyl iodide-127 and methyl iodide-131 penetration tests. It was found possible to regenerate the iodine isotope-exchange efficiency by reaction with airborne chemical reducing agents with little or no improvement in methyl iodine-127 retention. Examples will be given of the chemical regeneration of carbons after exhaustion with known contaminants as well as for many carbons removed from nuclear power operations. The depth profile of methyl iodide-131 penetration was determined in 2-inch deep layers before and after chemical treatments

  3. Duality in diffraction dissociations

    International Nuclear Information System (INIS)

    Santoro, Alberto.

    1977-01-01

    Diffractive dissociations (aN→a*πN) are naturally explained and a model that accounts for the three-variable correlation (mass-transfer-Jackson angle correlation) is presented. This model takes into account the three possible exchanges: t (pion), u(a*) and s(a) channel exchanger. The physical consequences of the model are: a strong mass-slope correlation due to the zeros of the amplitude, a factorization of diffractive dissociations (factorization of the Pomeron), the possibility of extending this model to double diffractive dissociation and diffraction by nuclei. This model was applied to the NN→NπN reaction. Using the usual parameters of the Deck model, a comparison is made with experiments for all available distributions. the strong slope of the peak at 1400 MeV is naturally explained [fr

  4. Weakly-bound adsorption states and low-temperature adsorption kinetiks of oxygen on tungsten (100) and (110) faces

    International Nuclear Information System (INIS)

    Zhukov, V.V.; Osovskij, V.D.; Ptushnikov, Yu.G.; Sukretnyj, V.G.; Chujkov, B.A.

    1986-01-01

    A molecular beam technique with an effusion source operating at T=200 K is used to study the adsorption interaction of oxygen with W(100) and (110) faces in the range of the simple temperatures from 5 to 340 K. Three weakly-bound adsorption states of oxygen are detected corresponding to adsorption in the second, third and forth monolayer. These states are characterized by adsorption energies of 0.13, 0.08 and 0.07 eV and desorption temperatures of 45, 27 and 25 K, respectively. The kinetics of filling of these states is almost similar for both faces, whereas the adsorption kinetics in the first monolayer is essentially different. A dissociative nature of adsorption at T >or approx. 5 K and a jump migration mechanism of the admolecules in the precursor state to the stationary adsorption sites are suggested

  5. Iodine removal from a gas phase

    International Nuclear Information System (INIS)

    Vikis, A. Ch.

    1982-01-01

    Iodine, e.g. radioactive iodine, present as one or more organic iodides, optionally with elemental iodine, in a gas phase (e.g. air) are removed by photochemically decomposing the organic iodides to elemental iodine, reacting the iodine produced, and any initially present with excess ozone, preferably photochemically produced in situ in the gas phase to produce solid iodine oxides, and removing the solid oxides from the gas phase. (author)

  6. Iodine removal from a gas phase

    International Nuclear Information System (INIS)

    Vikis, A.C.

    1984-01-01

    Iodine, e.g. radioactive iodine, present as one or more organic iodides, optionally with elemental iodine, in a gas phase (e.g. air) are removed by photochemically decomposing the organic iodides to elemental iodine, reacting the iodine produced, and any initially present with excess ozone, preferably photochemically produced in situ in the gas phase to produce solid iodine oxides, and removing the solid oxides from the gas phase

  7. Dissociative symptoms in kleptomania.

    Science.gov (United States)

    Grant, Jon E

    2004-02-01

    Many patients with kleptomania report an altered state of consciousness during acts of theft. The purpose of this investigation was to clarify a possible link between dissociation and kleptomania, a disabling disorder whose phenomenology remains understudied. 26 adult outpatients who met DSM-IV criteria for kleptoania were administered the Dissociative Experiences Scale and compared to 22 normal controls. The patients with kleptomania had scores that differed significantly from those reported by normal controls. There were no statistically significant differences by sex. Because kleptomania patients seeking treatment with medication may differ from others with kleptomania, further studies are needed.

  8. Iodine capture by Hofmann-type clathrate Ni(II)(pz)[Ni(II)(CN)_4

    International Nuclear Information System (INIS)

    Massasso, Giovanni; Long, Jerome; Haines, Julien; Devautour-Vinot, Sabine; Maurin, Guillaume; Larionova, Joulia; Guerin, Christian; Guari, Yannick; Grandjean, Agnes; Onida, Barbara; Donnadieu, Bruno

    2014-01-01

    The thermally stable Hofmann-type clathrate framework Ni(II)(pz)[Ni(II)(CN)_4] (pz = pyrazine) was investigated for the efficient and reversible sorption of iodine (I_2) in the gaseous phase and in solution with a maximum adsorption capacity of 1 mol of I_2 per 1 mol of Ni(II)pz)[Ni(II)(CN)_4] in solution. (authors)

  9. The Status of Iodine Nutrition and Iodine Deficiency Disorders ...

    African Journals Online (AJOL)

    Background: Iodine deficiency disorders are serious public health problems in Ethiopia. The aim of this study was to measure the prevalence and severity of iodine deficiency disorders among school children in Metekel Zone. Methods: A cross-sectional school based descriptive study was conducted between February 2011 ...

  10. Modelling the chemistry of iodine

    International Nuclear Information System (INIS)

    Paquette, J.

    1989-01-01

    We have assembled a kinetic model, based on elementary chemical reactions, that describes the chemical behaviour of iodine in aqueous solution as a function of time and various parameters such as pH, concentration and radiation field. The model is conceptually divided into six section: aqueous iodine chemistry, aqueous organic iodide chemistry, water radiolysis, radiolysis of iodine solutions, radiolysis of organic iodide solutions and mass transfer. The model indicates that, in the absence of a radiation field, the rate of production of volatile iodine species is controlled by the rate of oxidation of the iodide ion. The volatile iodine species are dominated by organic iodides if organic impurities are present. The single most important parameter controlling iodine volatility is the pH of the solution; high pH values tend to minimize iodine volatility. In the presence of a radiation field, the volatility of iodine is controlled by the radiation-induced oxidation of the iodide ion. Again, iodine volatility is dominated by organic iodides if organic impurities are present. High pH values minimize iodine volatility. A sensitivity analysis has been performed on some sections of the model to identify reactions to which the volatility of iodine is most sensitive. In the absence of a radiation field, the volatility is most sensitive, first, to the rate of oxidation of the iodide ion, and, second, to the rate of mass transfer of volatile species between the aqueous and the gaseous phases. This approach should be useful in identifying reactions for which accurate rate constants are required and in decreasing the complexity of the model. 37 refs

  11. Inter-row Adsorption Configuration and Stability of Threonine Adsorbed on the Ge(100) Surfaces

    International Nuclear Information System (INIS)

    Lee, Myungjin; Park, Youngchan; Jeong, Hyuk; Lee, Hangil

    2013-01-01

    The adsorption structures of threonine on the Ge(100) surface were investigated using core-level photoemission spectroscopy (CLPES) in conjunction with density functional theory (DFT) calculations. CLPES measurements were performed to identify the experimentally preferred adsorption structure. The preferred structure indicated the relative reactivities of the carboxyl and hydroxymethyl groups as electron donors to the Ge(100) surface during adsorption. The core-level C 1s, N 1s, and O 1s CLPES spectra indicated that the carboxyl oxygen competed more strongly with the hydroxymethyl oxygen during the adsorption reaction. Three among six possible adsorption structures were identified as energetically favorable using DFT calculation methods that considered the inter- and intra-bonding configurations upon adsorption onto the Ge(100) surface. These structures were O-H dissociated N dative inter bonding, O-H dissociated N dative intra bonding, O-H dissociation bonding. One of the adsorption structures: O-H dissociated N dative inter bonding was predicted to be stable in light of the transition state energies. We thus confirmed that the most favorable adsorption structure is the O-H dissociated N dative-inter bonding structure using CLPES and DFT calculation

  12. The sorption of iodine by an inorganic zinc primer

    Energy Technology Data Exchange (ETDEWEB)

    Evans, G J; Bekeris, P A [Toronto Univ., ON (Canada). Dept. of Chemical Engineering and Applied Chemistry

    1996-12-01

    The purpose of this work was to identify and evaluate significant parameters in the sorption of I{sub 2}(g) onto Carbo Zinc 11 inorganic primer, a paint used in the containment structure of some CANDU reactors. Air containing known amounts of {sup 131}I{sub 2}(g) was passed through 0.64 cm diameter glass tubing coated on the inner surface with paint. The accumulation of iodine on the surface was continuously monitored using two scintillation detectors. The test parameters covered were relative humidity, flow rate, I{sub 2} concentration and paint temperature. Adsorption was rapid at 23{sup o}C and predominantly gas phase mass transfer limited: the deposition velocity of 0.7{+-}0.4 cm/s was similar to the gas phase mass transfer coefficient of 1.2 cm/s estimated for the system. The deposition velocity observed at a higher paint surface temperature was an order of magnitude smaller. A similar deposition velocity was observed at 23{sup o}C for adsorption of I{sub 2}(g) from essentially dry air suggesting that the low deposition velocity observed for high surface temperature was limited by the amount of water on the paint surface. The rate of adsorption on the paint was directly proportional to the I{sub 2}(g) concentration over the range in concentration studied. The majority of the iodine retained by the paint could not be removed by washing with methanol or chloroform, but it was removed by water indicating that it was in an ionic form. Analysis of the speciation of the iodine in the wash water indicated that only a third of it was in the form of I{sup -}; the form of the remaining iodine could not be resolved. Desorption from the paint was negligible at room temperature but was detectable at higher temperatures. These low desorption rates and the ionic nature of the surface iodine indicated that adsorption occurred predominantly through a chemisorption process. A number of possible mechanisms were proposed. (author) 5 figs., 2 tabs., 6 refs.

  13. Radioactive Iodine and Krypton Control for Nuclear Fuel Reprocessing Facilities

    Directory of Open Access Journals (Sweden)

    Nick R. Soelberg

    2013-01-01

    Full Text Available The removal of volatile radionuclides generated during used nuclear fuel reprocessing in the US is almost certain to be necessary for the licensing of a reprocessing facility in the US. Various control technologies have been developed, tested, or used over the past 50 years for control of volatile radionuclide emissions from used fuel reprocessing plants. The US DOE has sponsored, since 2009, an Off-gas Sigma Team to perform research and development focused on the most pressing volatile radionuclide control and immobilization problems. In this paper, we focus on the control requirements and methodologies for 85Kr and 129I. Numerous candidate technologies have been studied and developed at laboratory and pilot-plant scales in an effort to meet the need for high iodine control efficiency and to advance alternatives to cryogenic separations for krypton control. Several of these show promising results. Iodine decontamination factors as high as 105, iodine loading capacities, and other adsorption parameters including adsorption rates have been demonstrated under some conditions for both silver zeolite (AgZ and Ag-functionalized aerogel. Sorbents, including an engineered form of AgZ and selected metal organic framework materials (MOFs, have been successfully demonstrated to capture Kr and Xe without the need for separations at cryogenic temperatures.

  14. Mechanism of pulse discharge production of iodine atoms from CF3I molecules for a chemical oxygen-iodine laser

    International Nuclear Information System (INIS)

    Kochetov, I V; Napartovich, A P; Vagin, N P; Yuryshev, N N

    2009-01-01

    The pulsed chemical oxygen-iodine laser (COIL) development is aimed at many new applications. Pulsed electric discharge is most effective in turning COIL operation into the pulse mode by instant production of iodine atoms. A numerical model is developed for simulations of the pulsed COIL initiated by an electric discharge. The model comprises a system of kinetic equations for neutral and charged species, electric circuit equation, gas thermal balance equation and the photon balance equation. Reaction rate coefficients for processes involving electrons are found by solving the electron Boltzmann equation, which is re-calculated in a course of computations when plasma parameters changed. The processes accounted for in the Boltzmann equation include excitation and ionization of atoms and molecules, dissociation of molecules, electron attachment processes, electron-ion recombination, electron-electron collisions, second-kind collisions and stepwise excitation of molecules. The last processes are particularly important because of a high singlet oxygen concentration in gas flow from the singlet oxygen chemical generator. Results of numerical simulations are compared with experimental laser pulse waveforms. It is concluded that there is satisfactory agreement between theory and the experiment. The prevailing mechanism of iodine atom formation from the CF 3 I donor in a very complex kinetic system of the COIL medium under pulse discharge conditions, based on their detailed numerical modelling and by comparing these results both with experimental results of other authors and their own experiments, is established. The dominant iodine atom production mechanism for conditions under study is the electron-impact dissociation of CF 3 I molecules. It was proved that in the conditions of the experiment the secondary chemical reactions with O atoms play an insignificant role.

  15. Dissociation and psychosis in dissociative identity disorder and schizophrenia.

    Science.gov (United States)

    Laddis, Andreas; Dell, Paul F

    2012-01-01

    Dissociative symptoms, first-rank symptoms of schizophrenia, and delusions were assessed in 40 schizophrenia patients and 40 dissociative identity disorder (DID) patients with the Multidimensional Inventory of Dissociation (MID). Schizophrenia patients were diagnosed with the Structured Clinical Interview for the DSM-IV Axis I Disorders; DID patients were diagnosed with the Structured Clinical Interview for DSM-IV Dissociative Disorders-Revised. DID patients obtained significantly (a) higher dissociation scores; (b) higher passive-influence scores (first-rank symptoms); and (c) higher scores on scales that measure child voices, angry voices, persecutory voices, voices arguing, and voices commenting. Schizophrenia patients obtained significantly higher delusion scores than did DID patients. What is odd is that the dissociation scores of schizophrenia patients were unrelated to their reports of childhood maltreatment. Multiple regression analyses indicated that 81% of the variance in DID patients' dissociation scores was predicted by the MID's Ego-Alien Experiences Scale, whereas 92% of the variance in schizophrenia patients' dissociation scores was predicted by the MID's Voices Scale. We propose that schizophrenia patients' responses to the MID do not index the same pathology as do the responses of DID patients. We argue that neither phenomenological definitions of dissociation nor the current generation of dissociation instruments (which are uniformly phenomenological in nature) can distinguish between the dissociative phenomena of DID and what we suspect are just the dissociation-like phenomena of schizophrenia.

  16. Dissociative Identity Disorder

    Science.gov (United States)

    Schmidt, Tom

    2007-01-01

    Few psychological disorders in the Diagnostic Statistical Manual have generated as much controversy as Dissociative Identity Disorder (DID). For the past 35 years diagnoses of DID, previously referred to as Multiple Personality Disorder (MPD), have increased exponentially, causing various psychological researchers and clinicians to question the…

  17. Volatilization of iodine from vegetation

    Energy Technology Data Exchange (ETDEWEB)

    Amiro, B D; Johnston, F L [Atomic Energy of Canada Ltd., Pinawa, MB (Canada). Whiteshell Nuclear Research Establishment

    1989-01-01

    Gaseous emissions of iodine were measured from bean plant foliage. A gamma-emitting iodine tracer, Na {sup 125}I, was taken up by the plants from a hydroponic growth medium and released to a cuvette atmosphere. The dynamics of the flux were studied using a flow-through gamma detector. The relationship between leaf radioactive tracer activity and growth-medium activity was linear, as was the relationship between the iodine flux and both leaf and growth-medium activity. Iodine flux and leaf conductance to water responded similarly to changes in light levels, suggesting that the stomata may partially control the flux. The flux was inhibited by aeration of the hydroponic growth media, and we postulate that methylation causes the iodine flux. Iodine emissions from living vegetation probably contribute < 0.1% to the stable iodine concentration in the atmosphere above terrestrial areas. However, this pathway may be a direct route for radioactive iodine transport from contaminated soils to the atmosphere. (author).

  18. Iodine metabolism and food needs

    International Nuclear Information System (INIS)

    Mornex, R.

    1992-01-01

    Iodine is an element that is necessary for the growth and mental development of a child and for the maintenance of the activity of all cells at all ages. In this article, the author recalls the iodine sources, its metabolism and the food needs and contributions

  19. Neurophysiological correlates of dissociative symptoms

    NARCIS (Netherlands)

    Kruijs, van der S.J.M.; Bodde, N.M.G; Carrette, E.C.B.; Lazeron, R.H.C; Vonck, K.E.J.; Boon, P.A.J.M.; Langereis, G.R.; Cluitmans, P.J.M.; Feijs, L.M.G.; Hofman, P.A.M.; Backes, W.H.; Jansen, J.F.A.; Aldenkamp, A.P.

    2014-01-01

    Objective: Dissociation is a mental process with psychological and somatoform manifestations, which is closely related to hypnotic suggestibility and essentially shows the ability to obtain distance from reality. An increased tendency to dissociate is a frequently reported characteristic of patients

  20. Studies of iodine concentration in steel and transition metals

    International Nuclear Information System (INIS)

    Kormann, C.; Kozlowski, W.; Oleksi-Frenzel, J.; Nachtigall, K.; Neste, A. van; Welsh, M.; Titze-Zaeske, B.; Plieth, W.

    1990-01-01

    Radioactive iodine which originates from nuclear fuel reprocessing plants as a fission product and consists mainly of the radioactive isotopes 129 I, 131 I, and of the inactive 127 I, must be quantitatively adsorbed at the end of the process for the purpose of safe waste disposal. Inspite of using high-alloy austenitic chrome nickel steels, major corrosion effects were observed at tubes and containers of the PASSAT dissolver waste gas purifier. This research project serves to clarify the question in which parts of the installation iodine concentration is to be expected under certain conditions. Furthermore it serves to identify the redox state of iodine in the various installation components. For this purpose steel (1.4306esu and 1.4563N), zirconium and titanium were studied in nitric iodic media. With the objective of calculating iodine adsorption isotherms, the following methods were used to obtain qualitative and quantitative data: FTIR, ellipsometry, 131 I radiotracer method, cyclo-voltametry, closed circuit potential measurements, ion chromatography. (orig./DG) [de

  1. The development of advanced gas cooled reactor iodine adsorber systems

    International Nuclear Information System (INIS)

    Meddings, P.

    1986-01-01

    Advanced Gas Cooled Reactors (AGRs) are provided with plants to process the carbon dioxide coolant prior to its discharge to atmosphere. Included in these are beds of granular activated charcoal, contained within a suitable pressure vessel, through which the high pressure carbon dioxide is passed for the purpose of retaining iodine and iodine-containing compounds. Carry-over carbon dust from the adsorption beds was identified during active in-situ commissioning testing, radio-iodine being transported with the particulate material due to gross disturbance of the adsorber carbon bed and displacement of the vessel internals. The methods used to identify the causes of the problems and find solutions are described. A development programme for the Heysham-2 and Torness reactors iodine adsorber units was set up to identify a method of de-dusting granular charcoal and develop it for full-scale use, of assess the effect under conditions of high gas density of approach velocity on charcoal fines production and to establish the pressure drop characteristics of a packed granular bed and to develop an effective design of inlet gas diffuser manifold to ensure an acceptable velocity distribution. This has involved the construction of a small scale high pressure carbon dioxide rig and development of an air flow model. This work is described. (UK)

  2. Breastfeeding and maternal and infant iodine nutrition.

    Science.gov (United States)

    Azizi, Fereidoun; Smyth, Peter

    2009-05-01

    The aim of this review is to explore information available regarding iodine secretion in milk, both mothers and infants iodine nutrition during breastfeeding and to make recommendations for appropriate iodine supplementation during lactation. MEDLINE was queried for studies between 1960 and 2007 that included lactation and breastfeeding with iodine and iodine deficiency. Studies were selected if they studied (i) Secretion of iodine in breast milk; (ii) breastfeeding and iodine nutrition; (iii) factors affecting maternal iodine metabolism and (iv) recommendations for iodine supplementation during breastfeeding. Thirty-six articles met the selection criteria. The iodine content of breast milk varies with dietary iodine intake, being lowest in areas of iodine deficiency with high prevalence of goitre. Milk iodine levels are correspondingly higher when programs of iodine prophylaxis such as salt iodization or administration of iodized oil have been introduced. The small iodine pool of the neonatal thyroid turns over very rapidly and is highly sensitive to variations in dietary iodine intake. Expression of the sodium iodide symporter is up-regulated in the lactating mammary gland which results in preferential uptake of iodide. In areas of iodine sufficiency breast milk iodine concentration should be in the range of 100-150 microg/dl. Studies from France, Germany, Belgium, Sweden, Spain, Italy, Denmark, Thailand and Zaire have shown breast milk concentrations of nutrition. The current WHO/ICCIDD/UNICEF recommendation for daily iodine intake (250 microg for lactating mothers) has been selected to ensure that iodine deficiency dose not occur in the postpartum period and that the iodine content of the milk is sufficient for the infant's iodine requirement.

  3. Three dimensions of dissociative amnesia.

    Science.gov (United States)

    Dell, Paul F

    2013-01-01

    Principal axis factor analysis with promax rotation extracted 3 factors from the 42 memory and amnesia items of the Multidimensional Inventory of Dissociation (MID) database (N = 2,569): Discovering Dissociated Actions, Lapses of Recent Memory and Skills, and Gaps in Remote Memory. The 3 factors' shared variance ranged from 36% to 64%. Construed as scales, the 3 factor scales had Cronbach's alpha coefficients of .96, .94, and .93, respectively. The scales correlated strongly with mean Dissociative Experiences Scale scores, mean MID scores, and total scores on the Structured Clinical Interview for DSM-IV Dissociative Disorders-Revised (SCID-D-R). What is interesting is that the 3 amnesia factors exhibited a range of correlations with SCID-D-R Amnesia scores (.52, .63, and .70, respectively), suggesting that the SCID-D-R Amnesia score emphasizes gaps in remote memory over amnesias related to dissociative identity disorder. The 3 amnesia factor scales exhibited a clinically meaningful pattern of significant differences among dissociative identity disorder, dissociative disorder not otherwise specified-1, dissociative amnesia, depersonalization disorder, and nonclinical participants. The 3 amnesia factors may have greater clinical utility for frontline clinicians than (a) amnesia as discussed in the context of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, nosology of the dissociative disorders or (b) P. Janet's (1893/1977 ) 4-fold classification of dissociative amnesia. The author recommends systematic study of the phenomenological differences within specific dissociative symptoms and their differential relationship to specific dissociative disorders.

  4. Iodine/steel reactions under severe accident conditions in LWR's

    International Nuclear Information System (INIS)

    Funke, F.; Greger, G-U.; Hellman, S.; Bleier, A.; Morell, W.

    1994-01-01

    Due to large surface areas, the reaction of volatile, molecular iodine (I 2 ) with steel surfaces in the containment may play an important role in predicting the source term to the environment. Both wall retention of iodine and conversion of volatile into non-volatile iodine compounds at steel surfaces have to be considered. Two types of laboratory experiments were carried out at Siemens/KWU in order to investigate the reaction of I 2 at steel surfaces representative for German power plants. 1) For steel coupons submerged in an I 2 solution at T = 50 deg C, 90 deg C or 140 deg C the reaction rate of the I 2 /I - conversion was determined. No iodine loading was observed on the steel in the aqueous phase tests. I 2 reacts with the steel components (Fe, Cr or Ni) to form metal iodides on the surface which are all immediately dissolved in water under dissociation into the metal and the iodide ions. From these experiments, the I 2 /I - conversion rate constants over the temperature range 50 deg C - 140 deg C as well as the activation energy were determined. The measured data are suitable to be included in severe accident iodine codes such as IMPAIR. 2) Steel tubes were exposed to a steam/I 2 flow under dry air at T=120 deg C and steam-condensing conditions at T= 120 deg C and 160 deg C. In dry air I 2 was retained on the steel surface and a deposition rate constant was measured. Under steam-condensing conditions there is an effective conversion of volatile I 2 to non-volatile I - which is subsequently washed off from the steel surface. The I 2 /I - conversion rate constants suitable for modelling this process were determined. No temperature dependency was found in the range 120 deg C - 160 deg C. (author). 4 refs., 2 tabs., 7 figs

  5. Adsorption of Acetic Acid, Cadmium ions, Lead ions and Iodine ...

    African Journals Online (AJOL)

    This paper presents the performance evaluation of locally prepared activated carbon from rice husk and saw dust. The raw materials were carbonized at different temperatures (600-800oC) using sodium hydroxide (NaOH) as the activating agent. The study includes moisture content determination of the raw materials used ...

  6. Effectiveness and risks of stable iodine prophylaxis

    International Nuclear Information System (INIS)

    Waight, P.J.

    1995-01-01

    The factors upon which the efficacy of stable iodine prophylaxis depends are reviewed, with particular reference to the dose of stable iodine, the timing of the dose, the influence of dietary iodine and the impact of the other prospective actions. The risks of stable iodine ingestion are estimated, and their application to the principle of Justification in outlined. (Author)

  7. Electronic structures and reactivities of iodinating agents in the gas phase and in solutions: a density functional study

    International Nuclear Information System (INIS)

    Filimonov, V.D.; Krasnokutskaya, E.L.; Lesina, Yu.A.; Chajkovskij, V.K.; Poleshchuk, O.X.

    2006-01-01

    The electronic and spatial structures of a broad spectrum of neutral compounds with X-Hal (X = N, O, Cl; Hal = Cl, Br, I) bonds and their protonated forms and of different electronic states of triiodide cation, I 3 + , were determined from density functional B3LYP/6-311G* quantum-chemical calculations. The effects of the structure of these compounds on the parameters of electrophilic reactivity were revealed and the thermochemical characteristics of homolytic and heterolytic X-Hal bond dissociation and of iodine transfer in hydroxyl-containing solvents were calculated. Due to low homolytic bond dissociation energies of X-I, the formation of molecular iodine and triiodide cation I 3 + becomes thermodynamically favorable and the cation should act as iodinating agent alternative to acylhypoiodites and N-iodoimides. The solvation effects of MeOH and CH 2 Cl 2 on the X-Hal bond homolysis and heterolysis were determined using the PCM model [ru

  8. Iodine in the environment revisited

    International Nuclear Information System (INIS)

    Christiansen, J.V.; Carlsen, L.

    1989-05-01

    The report gives an overview of the environmental cycle of iodine, especially focusing on the possible reactions being responsible for the retention of iodine in the terrestrial environment. During the last two decades evidence for the presence of iodine in soil as organically bound has been presented. The major part of inorganic iodine in the terrestrial environment will, under physical and chemical conditions normally prevailing, exist as iodide. No evidence for a direct reaction between iodide and organic material has been presented, whereas strong support for the engagement of microbial activity in the formation of organic iodine compounds in soil has been obtained. Incorporation of iodine in humic substances as a result of enzymatic catalysis, involving an enzyme of the perozidase group apperas reasonable. It is concluded that microbiological activity involving extracellular enzymes most probably is responsible for the possible retention of iodine in the terrestrial environment. It is suggested that these reactions in detail should be studied experimentally. (author) 3 tabs., 2 ills., 51 refs

  9. Iodine deficiency and nutrition in Scandinavia

    DEFF Research Database (Denmark)

    Manousou, Sofia; Dahl, Lisbeth; Heinsbaek Thuesen, Betina

    2017-01-01

    Iodine nutrition is a result of geological conditions, iodine fortification and monitoring strategies within a country together with the dietary habits of the population. This review summarizes the basis for the current iodine situation in the Scandinavian countries in order to identify gaps...... strategies have been used in Scandinavia to improve iodine nutrition. The major source of iodine is iodized salt in Sweden and from milk and dairy products in Norway. In Denmark, drinking water, milk, dairy products and iodized salt used in commercial production of bread are the important sources of iodine....... The current iodine status in Scandinavia is not optimal and action is ongoing to increase iodination in Denmark, where there is mild iodine deficiency in the general population. Data from all three countries indicate insufficient iodine nutrition during pregnancy and there is a need for data from children...

  10. Iodine excretion in school children in Copenhagen

    DEFF Research Database (Denmark)

    Rasmussen, Lone B.; Kirkegaard-Klitbo, Ditte Marie; Laurberg, Peter

    2016-01-01

    INTRODUCTION: Studies of dietary habits show a high iodine intake in children in Denmark. Iodine excretion in children has not previously been assessed. Iodine excretion in adults is below the recommended threshold, and it is therefore being discussed to increase the fortification level. The main...... objective of this study was to assess iodine excretion in children living in Copenhagen to establish whether a moderate increase in iodine fortification would lead to excess iodine intake in this group. METHODS: Children in first and fifth grade were recruited through schools in Copenhagen. In total, 244...... children de-ivered a urine sample. Urine samples were analysed for iodine and creatinine, and the results were expressed as urinary iodine concentration (UIC) and as estimated 24-h iodine excretion. Iodine excretion in children was also compared with that of adults living in the same area, investigated...

  11. Innovative nanoporous carbons with ultrahigh uptakes for capture and reversible storage of CO{sub 2} and volatile iodine

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Hanxue; La, Peiqing [College of Petrochemical Technology, Lanzhou University of Technology, Langongping Road 287, Lanzhou 730050, PR China (China); Yang, Ruixia [State Key Laboratory of Molecular Reaction Dynamics, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); Zhu, Zhaoqi; Liang, Weidong; Yang, Baoping [College of Petrochemical Technology, Lanzhou University of Technology, Langongping Road 287, Lanzhou 730050, PR China (China); Li, An, E-mail: lian2010@lut.cn [College of Petrochemical Technology, Lanzhou University of Technology, Langongping Road 287, Lanzhou 730050, PR China (China); Deng, Weiqiao, E-mail: dengwq@dicp.ac.cn [State Key Laboratory of Molecular Reaction Dynamics, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China)

    2017-01-05

    Highlights: • Cigarette filter was utilized to prepare highly porous carbons as super absorbents. • The porous carbons exhibit excellent iodine uptake. • The porous carbons show high CO{sub 2} adsorption capacity of 6.0 mmol g{sup −1} at 273 K. - Abstract: Porous carbons as solid-state adsorbents have recently attracted considerable interest in the areas of storage and capture of CO{sub 2} as well as the adsorption of radioactive matters. In this work, cigarette butts, one kind of common wastes referring to the filters, were utilized to prepare highly porous carbons by KOH activation in argon atmosphere. The resulting porous carbon shows a high specific surface area of up to 2751 m{sup 2} g{sup −1} with abundant micropores. The resulting porous carbon exhibits excellent iodine uptake of 262 wt% and high CO{sub 2} adsorption capacity of 6.0 mmol g{sup −1} at ambient pressure and 273 K, which both are among the highest values reported to date. Given these excellent iodine uptake, CO{sub 2} adsorption capacity, ease of preparation as well as good physiochemical stability, the porous carbons derived from cigarette butts show great potential in the reversible adsorption of radioactive iodine and CO{sub 2}.

  12. Iodine isotopes and radiation safety

    International Nuclear Information System (INIS)

    Styro, B.; Nedvekajte, T.; Filistovich, V.

    1992-01-01

    Methods of concentration determination of stable and radioactive iodine isotopes in the Earth's different geospheres are described. Iodine isotopes concentration data, chemical forms and transformations as well as their exchange among separate geospheres of their global biochemical circulation (ocean, atmosphere, lithosphere and biosphere) are presented. Information on iodine isotopes as after-effects of nuclear installations accident (in particular, the Chernobyl accident) is generalized. The book is intended for scientists and practical workers in ecology and radioactivity protection and for a students of physics. 442 refs.; 82 figs.; 36 tabs

  13. Radiochemistry of iodine

    Energy Technology Data Exchange (ETDEWEB)

    Kahn, M.; Kleinberg, J.

    1977-09-01

    The preparation of isotopes of the element, with selected procedures for its determination in or separation from various media is described along with the separating of iodine species from each other. Each part of the introductory section is referenced separately from the remainder of the monograph. For the preparative and analytical sections there is an extensive, indexed bibliography which was developed from the indexes of Volumes 19 to 30 inclusive (1965-1974) of Nuclear Science Abstracts (NSA). From these indexes the NSA abstracts of possible pertinent references were selected for examination and a choice was made of those references which were to be included in the bibliography. The bibliography has both primary and secondary references. Although the monograph does not cover hot atom chemistry, the kinetics of exchange reactions, decay schemes, or physiological applications, papers in these areas were examined as possible sources of useful preparative and analytical procedures. (JRD)

  14. Radiochemistry of iodine

    International Nuclear Information System (INIS)

    Kahn, M.; Kleinberg, J.

    1977-09-01

    The preparation of isotopes of the element, with selected procedures for its determination in or separation from various media is described along with the separating of iodine species from each other. Each part of the introductory section is referenced separately from the remainder of the monograph. For the preparative and analytical sections there is an extensive, indexed bibliography which was developed from the indexes of Volumes 19 to 30 inclusive (1965-1974) of Nuclear Science Abstracts (NSA). From these indexes the NSA abstracts of possible pertinent references were selected for examination and a choice was made of those references which were to be included in the bibliography. The bibliography has both primary and secondary references. Although the monograph does not cover hot atom chemistry, the kinetics of exchange reactions, decay schemes, or physiological applications, papers in these areas were examined as possible sources of useful preparative and analytical procedures

  15. Current iodinated contrast media

    International Nuclear Information System (INIS)

    Stacul, F.

    2001-01-01

    The number of scientific papers on iodinated contrast media is declining. Indeed, comparative trials between high-osmolality and low-osmolality agents largely showed the higher safety and tolerability of the latter, and this is no longer a matter of discussion. Only financial constraints could prevent a total conversion to low-osmolality agents. Research comparing low-osmolality (nonionic monomers, ionic dimer) and iso-osmolality contrast media (nonionic dimers) are still ongoing. Both classes of nonionic compounds proved safer than the ionic dimer. The relative merits of nonionic monomers and nonionic dimers are a matter for debate, and criteria for a selective use of different agents for different procedures could be discussed. (orig.)

  16. 77 FR 60481 - Design, Inspection, and Testing Criteria for Air Filtration and Adsorption Units of Post-Accident...

    Science.gov (United States)

    2012-10-03

    ... filtration and iodine adsorption units of ESF atmosphere cleanup systems in light-water-cooled nuclear power... Filtration and Adsorption Units of Post-Accident Engineered-Safety-Feature Atmosphere Cleanup Systems in Light-Water-Cooled Nuclear Power Plants AGENCY: Nuclear Regulatory Commission. ACTION: Regulatory guide...

  17. Adsorption of radioactive I2 gas onto fly-ash aerosol

    International Nuclear Information System (INIS)

    Noguchi, Hiroshi; Murata, Mikio; Suzuki, Katsumi.

    1988-01-01

    The adsorption of radioactive elemental iodine (I 2 ) gas onto fly-ash aerosol has been studied to provide basic data for the realistic and precise assessment of dose to the general public from radioiodine released from nuclear facilities. A mixture of fly-ash aerosol and 131 I 2 gas was passed through a cylindrical glass vessel so that particulate iodine was formed by adsorption of I 2 onto aerosol. Then the concentrations of I 2 and particulate iodine were measured. It was found that the adsorption reached an equilibrium state between 5 and 12 min and that the proportion of iodine which was adsorbed on the aerosol decreased with increasing initial I 2 concentration ranging over 10 -13 to 10 -9 g/cm 3 . The adsorption isotherm of the aerosol for I 2 gas approximately followed Freundlich isotherm. Using the adsorption isotherm, a theoretical equation was derived to explain the adsorption on the basis of FUCHS' theory on the evaporation of droplets. A sticking probability in the equation decreased with increasing adsorbed amount. The calculated results were in good agreement with the experimental ones. (author)

  18. Environmental behavior of technetium-99 and iodine-129

    International Nuclear Information System (INIS)

    Garland, T.R.; Schreckhise, R.G.

    1982-01-01

    The environmental behavior of technetium-99 and iodine-129 was once thought to be similar, particularly with respect to their soil solubility and biological interactions. Over the past several years, the comparative behavior of these two anions has been studied with respect to their fate in natural environments (both aquatic and terrestrial). The mechanisms studied include physical, chemical and biological parameters that account for differences in soil behavior, cycling between soil and/or air to vegetation, adsorption and metabolism in plants, and their availability and fate following ingestion by animals

  19. Behavior of highly radioactive iodine on charcoal in moist air

    International Nuclear Information System (INIS)

    Lorenz, R.A.; Manning, S.R.; Martin, W.J.

    1976-01-01

    The behavior of highly radioactive iodine adsorbed on charcoal exposed to moist air (110 torr water vapor partial pressure) was investigated in a series of six experiments. The amount of radioactive 130 I on the well-insulated 28-cm 3 bed ranged from 50 to 570 Ci, and the relative humidity was 47 percent at the bed inlet temperature of 70 0 C. Radioactive iodine was released from the test beds at a continuous fractional release rate of approximately 7 x 10 -6 /hr for all types of charcoal tested. The chemical form of the released iodine was such that it was very highly penetrating with respect to the nine different types of commercial impregnated charcoals tested in backup collection beds. Two types of silver-nitrate-coated adsorption materials behaved similarly to the charcoals. Silver-exchanged type 13-X molecular sieve adsorbers were 20 to 50 times more efficient for adsorbing the highly penetrating iodine, but not as efficient as normally found for collecting methyl iodide. The chemical form of the highly penetrating iodine was not determined. When the moist air velocity was decreased from 28.5 fpm (25 0 C) to as low as 0.71 fpm (25 0 C), the charcoal bed temperature rose slowly and reached the ignition temperature in three of the experiments. At 0.71 fpm (25 0 C) the ignited charcoal beds reached maximum temperatures of 430 to 470 0 C because of the limited oxygen supply. The charcoal exposed for four years at Oak Ridge ignited at 283 0 C compared with 368 0 C for unused charcoal from the same batch. Two of the experiments used charcoal containing 1 or 2 percent TEDA (triethylene-diamine) and a proprietary flame retardant. The oxidation and ignition behavior of these charcoals did not appear to be affected adversely by the presence of the TEDA

  20. Immobilization of iodine in concrete

    Science.gov (United States)

    Clark, Walter E.; Thompson, Clarence T.

    1977-04-12

    A method for immobilizing fission product radioactive iodine recovered from irradiated nuclear fuel comprises combining material comprising water, Portland cement and about 3-20 wt. % iodine as Ba(IO.sub.3).sub.2 to provide a fluid mixture and allowing the fluid mixture to harden, said Ba(IO.sub.3).sub.2 comprising said radioactive iodine. An article for solid waste disposal comprises concrete prepared by this method. BACKGROUND OF THE INVENTION This invention was made in the course of, or under a contract with the Energy Research and Development Administration. It relates in general to reactor waste solidification and more specifically to the immobilization of fission product radioactive iodine recovered from irradiated nuclear fuel for underground storage.

  1. Study on solubility and leaching property of Iodine-129 waste-forms for geological disposal. Document prepared by other institute, based on the trust contract

    Energy Technology Data Exchange (ETDEWEB)

    Sakashita, A.; Izumi, J. [Mitsubishi Heavy Industries, Ltd., Tokyo (Japan); Kitao, H. [Nuclear Development Corp., Tokai, Ibaraki (Japan); Ueta, S.; Okada, K.; Nakazawa, T.; Muroi, M. [Mitsubishi Materials Corp., Tokyo (Japan)

    2002-02-01

    As concern the study on the property of Iodine-129 waste-forms, the solubilities and leachabilities of iodine-sodalite and leachabilities of apatite containing Iodine were measured last year. The results in this year are summarized as follows. 1. Solubility and Leachability of Iodine-sodalite. Leachabilities and solubilities of the synthesized iodine-sodalite by HIP method were measured by means of a long-term leach test in the solution with chloride ions and high pH (12.5). The measured solubilities were within a range of 10{sup -3} - 10{sup -2} mol/L, which were larger compare with the previous values. The leachabilities were 10{sup -6} g/cm{sup 2}/day (powder) and 10{sup -3} g/cm{sup 2}/day (block). After the leach test, the solid phases were analyzed and the alternation was not observed. 2. Leaching Property of Apatite Sample which contains Iodine adsorption medicine. Apatite sample was manufactured from apatite and zeorait which adsorbs iodine matrix by plasma-hotpress. The porosity of the samples was under 5% and release rate of iodine was about 10% at plasma-hotpress manufacturing. The leachabilities of iodine were 10{sup -4} - 10{sup -3} g/cm{sup 2}/d at 56 day soaking period. These values were 1 - 2 digits higher compare with the leachabilities of calcium. It is thought that the iodine selectively is leached from apatite sample. (author)

  2. Predictability of iodine chemistry in the containment of a nuclear power plant under hypothetical severe accident conditions

    Energy Technology Data Exchange (ETDEWEB)

    Herranz, L.E.; Vela-Garcia, M.; Fontanet, J. [Unit of Nuclear Safety Research, CIEMAT, Madrid (Spain)

    2007-07-01

    One of the areas of top interest in the arena of severe accidents to get an accurate prediction of Source Term is Iodine Chemistry. In this paper an assessment of the current capability of MELCOR and ASTEC to predict iodine chemistry within containment in case of a postulated severe accident has been carried out. The experiments FPT1 and FPT2 of the PHEBUS-FP project have been used for comparisons, since they were carried out under rather different containment conditions during the chemistry phase (subcooled vs. saturated sump or acid vs. alkaline pH), which makes them very suitable to assess the current modeling capability of in-containment iodine chemistry models. The results obtained indicate that, even though, both integral codes have specific areas related to iodine chemistry that should be further developed and that their approach to the matter is drastically different, at present ASTEC-IODE allows for a more comprehensive simulation of the containment iodine chemistry. More importantly, lack of maturity of these codes would potentially maximize the so-called user-effect, so that it would be highly recommendable to perform sensitivity studies around iodine chemistry aspects when calculating Source Term scenarios. Key aspects needed of further research are: gaseous iodine chemistry (absent in MELCOR), organic iodine chemistry and adsorption/desorption on/from containment surfaces. (authors)

  3. Milk Iodine Content in Slovakia

    Directory of Open Access Journals (Sweden)

    I. Paulíková

    2008-01-01

    Full Text Available The aim of this work was to map actual iodine status and its seasonal differences in raw milk of dairy cows, sheep, and goats in various regions of Slovakia. Iodine concentrations were determined in 457 samples of raw milk from dairy cows, 78 samples of sheep, and 16 samples of goat milk collected in various regions of Slovakia from 2002 to 2007. Among all the 457 samples of bovine milk, iodine content below 50 μg l-1 was recorded in 114 samples (24.94%; 294 samples (64.33% ranged between 50 and 200 μg l-1; 19 samples (4.16% from 200 to 500 μg l-1; 17 samples (3.72% between 500 and 1 000 μg l-1, and 13 samples (2.85% showed iodine concentrations over 1 000 μg l-1. regional concentrations showed the highest values in the Western, then Middle and Eastern Slovakia, and the lowest values in Northern Slovakia (p p -1 in 49 sheep (62.8% and in 6 goats below 60 μg l-1 (37.5%, which are indicative of iodine deficiency. When comparing seasonal differences, sheep and goat milk had higher iodine content during the winter feeding period, however, in dairy cows we recorded the opposite ratio. Except for goat milk (p < 0.01 the seasonal differences were not significant.

  4. Organic iodine removal from simulated dissolver off-gas systems utilizing silver-exchanged mordenite

    International Nuclear Information System (INIS)

    Jubin, R.T.

    1981-01-01

    The removal of methyl iodide by adsorption onto silver mordenite was studied using a simulated off-gas from the fuel dissolution step of a nuclear fuel reprocessing plant. The adsorption of methyl iodide on silver mordenite was examined for the effect of NO/sub x/, humidity, iodine concentration, filter temperature, silver loadings and filter pretreatment. The highest iodine loading achieved in these tests was 142 mg CH 3 I per g of substrate on fully exchanged zeolite, approximately the same as elemental iodine loadings. A filter using fully exchanged silver mordenite operating at 200 0 C obtained higher iodine loadings than a similar filter operating at 150 0 C. Pretreatment of the sorbent bed with hydrogen rather than dry air, at a temperature of 200 0 C, also improved the loading. Variations in the methyl iodide concentration had minimal effects on the overall loading. Filters exposed to moist air streams attained higher loadings than those in contact with dry air. Partially exchanged silver mordenite achieved higher silver utilizations than the fully exchanged material. The partially exchanged mordenite also achieved higher loadings at 200 0 C than at 250 0 C. The iodine loaded onto these beds was not stripped at 500 0 C by either 4.5% hydrogen or 100% hydrogen; however, the iodine could be removed by air at 500 0 C, and the bed could be reloaded. A study of the regeneration characteristics of fully exchanged silver mordenite indicates limited adsorbent capacity after complete removal of the iodine with 4.5% hydrogen in the regeneration gas stream at 500 0 C. The loss of adsorbent capacity is much higher for silver mordenite regenerated in a stainless steel filter housing than in a glass filter housing

  5. Estimation of surface area and pore volume of activated carbons by methylene blue and iodine numbers

    Directory of Open Access Journals (Sweden)

    Cleiton A. Nunes

    2011-01-01

    Full Text Available Data of methylene blue number and iodine number of activated carbons samples were calibrated against the respective surface area, micropore volume and total pore volume using multiple regression. The models obtained from the calibrations were used in predicting these physical properties of a test group of activated carbon samples produced from several raw materials. In all cases, the predicted values were in good agreement with the expected values. The method allows extracting more information from the methylene blue and iodine adsorption studies than normally obtained with this type of material.

  6. Investigations on the retention of 131I by an iodine filter of a pressurized water reactor

    International Nuclear Information System (INIS)

    Deuber, H.; Gerlach, K.

    1983-09-01

    The retention of 131 I by an equipment room exhaust filter of a German pressurized water reactor was determined by various methods to particularly obtain reliable results. Moreover, investigations were performed to clarify the reason for aging of the carbon contained in the iodine filter mentioned. The actual retention of the organic 131 I, corresponding to a value of 99.9%, was limited by 131 I in the form of penetrating iodine compounds. It was lower than the retention of CH 3 131 I under layout conditions by more than one order of magnitude. The aging was essentially caused by the adsorption of low-volatile organic compounds. (orig.) [de

  7. Investigations on the retention of I-131 by an iodine filter of a pressurized water reactor

    International Nuclear Information System (INIS)

    Deuber, H.; Gerlach, K.

    1984-01-01

    The retention of I-131 by an equipment room exhaust filter of a German pressurized water reactor was determined by various methods to particularly obtain reliable results. Moreover, investigations were performed to clarify the reason for aging of the carbon contained in the iodine filter mentioned. The actual retention of the organic I-131, corresponding to a value of 99.9%, was limited by I-131 in the form of penetrating iodine compounds. It was lower than the retention of CH 3 I-131 under layout conditions by more than one order of magnitude. The aging was essentially caused by the adsorption of low-volatile organic compounds. (orig.) [de

  8. Iodine filters in nuclear power stations

    International Nuclear Information System (INIS)

    Wilhelm, J.G.

    1977-04-01

    On the basis of calculated and recorded release rates of nuclear power plants, the significance of iodine releases in the invironmental impact relative to other nuclides is discussed. The release pathways for iodine in LWR-type reactors and the efficiency of various methods to lower the activity release are given. The airborne species of iodine are discussed with regard to their removal in iodine sorption filters and environmental impact. The technical status of iodine removal by means of iodine sorption filters is studied for normal operation and accident conditions in nuclear power stations on the basis of the data given in the relevant literature for the efficiency of a number of iodine sorption materials. The applicability of concepts for ventilation and containment and their influence on iodine filter systems are discussed. Design, structure, and testing of iodine sorption filters are treated in detail; recommendations for design are given, and failure sources are mentioned. (orig.) [de

  9. Iodine status in neonates in Denmark

    DEFF Research Database (Denmark)

    Nøhr, S B; Laurberg, Peter; Børlum, K G

    1994-01-01

    Iodine status of 147 neonates born in five different regions of Denmark was evaluated in relation to the iodine content of breast milk and iodine supplementation taken by the mother. Approximately two-thirds of the women had not received iodine supplementation. They had low iodine concentrations...... in breast milk and urinary iodine concentrations of the neonates at day 5 were low. The median values (milk/urine) were 33.6/31.7 micrograms/l (Randers 22/26, Ringkøbing 29/16, Aalborg 36/31. Arhus 54/41 and Copenhagen 55/59 micrograms/l). Higher values were found in the group where tablets containing...... iodine had been taken (milk/urine: 57.0/61.0 micrograms/l). In general, the values are low compared with internationally recommended levels. We suggest that mothers without autoimmune thyroid disease should receive iodine supplementation in the form of vitamin/mineral tablets containing iodine (150...

  10. Capture of elemental and organic iodine from dilute gas streams by silver-exchanged mordenite

    Energy Technology Data Exchange (ETDEWEB)

    Bruffey, S.H.; Jubin, R.T.; Jordan, J.A. [Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37831 (United States)

    2016-07-01

    The treatment of off-gas streams arising from reprocessing of used nuclear fuel (UNF) is an area of active study by the U.S. Department of Energy. Such off-gas streams contain volatile fission products, including long-lived {sup 129}I. Although {sup 129}I is released into the off-gas at multiple points within the chemical reprocessing flowsheet, previous research has focused on removal from the dissolver off-gas stream (DOG). The DOG is expected to contain up to 98% of iodine in UNF at ppm levels within the stream. Other off-gas streams will also contain iodine but at substantially lower concentrations. Recent work has shown that compliance with U.S. regulations will likely require capture of iodine from these dilute streams in addition to capture from DOG. In particular, the vessel off-gas (VOG) stream is expected to contain 1-3% of the total iodine inventory at ppb concentrations. A review of literature also indicates that the speciation of iodine in the VOG stream will differ from that of the DOG, with the DOG containing primarily I{sub 2} and the VOG containing a mixture of I{sub 2} and organic iodine species. Silver-exchanged mordenite (AgZ) has been identified for use in the removal of iodine from off-gas streams. It is an effective capture material for I{sub 2} at the concentrations expected in the DOG, but little is known about its performance in gas streams that may contain both I{sub 2} and organic iodides at very dilute concentrations. The experiments to be described were designed to separately characterize the adsorption of I{sub 2} and methyl iodide on AgZ through extended duration testing. Simulated vessel off-gases containing low levels of either I{sub 2} or methyl iodide were contacted with AgZ sorbent beds for up to four months. Through the use of sorbent beds in series and varied sampling times, key parameters such as adsorption rate, decontamination factor, and performance over time could be determined for the capture of each species by AgZ. This

  11. Adsorption and decomposition of H{sub 2}O on cobalt surfaces: A DFT study

    Energy Technology Data Exchange (ETDEWEB)

    Ma, F.F.; Ma, S.H., E-mail: msh8586@163.com; Jiao, Z.Y.; Dai, X.Q.

    2016-10-30

    Highlights: • Molecular water weakly binds to Co surfaces and it is feasible to desorption from the clean surfaces. • The presence of atomic oxygen has a prominent promotion effect on the dissociation of water into hydroxyl, especially on O-covered Co(110) no extra energy is needed to dissociate H{sub 2}O. • Distinctively, the presence of hydroxyl hinders the dissociation of water molecule. • The analysis of microscopic decomposition behaviors demonstrates that molecular water adsorbs dissociatively with the aid of pre-adsorbed oxygen atom, forming OH radicals chemisorbed on the considered surfaces. - Abstract: Water adsorption and dissociation on clean and O-covered Co(100), Co(110) and Co(111) surfaces are studied using the density functional theory calculations. The results indicate that molecular water weakly binds to the surfaces and is feasible to desorption from the clean surfaces. Moreover, the pre-adsorption of O atom increases the binding of water to the surfaces, and prominently decreases the activation barriers of water dissociation into OH, especially on Co(110) surface. In contrast, the activation barrier for OH dissociation is slightly affected in the presence of O atom. Overall, this study reveals that O-assisted H{sub 2}O favorably adsorbs dissociatively, forming OH chemisorbed on the surfaces, which further hinders H{sub 2}O dissociation, and also illustrates the fact that molecular water dissociation is structure-sensitive on metal surfaces.

  12. CO dissociation on magnetic Fen clusters

    KAUST Repository

    Jedidi, Abdesslem

    2014-01-01

    This work theoretically investigates the CO dissociation on Fen nanoparticles, for n in the range of 1-65, focusing on size dependence in the context of the initial step of the Fischer-Tropsch reaction. CO adsorbs molecularly through its C-end on a triangular facet of the nanoparticle. Dissociation becomes easier when the cluster size increases. Then, the C atom is bonded to a square facet that is generated as a result of the adsorption if it does not yet exist in the bare cluster, while the O atom is adsorbed on a triangular facet. In the most stable situation, the two adsorbed atoms remain close together, both having in common one shared first-neighbor iron atom. There is a partial spin quenching of the neighboring Fe atoms, which become more positively charged than the other Fe atoms. The shared surface iron atom resembles a metal-cation from a complex. Despite the small size of the iron cluster considered, fluctuations due to specific configurations do not influence properties for n > 25 and global trends seem significant.

  13. Computational study of ethanol adsorption and reaction over rutile TiO2 (110) surfaces

    KAUST Repository

    Muir, J. N.

    2012-01-01

    Studies of the modes of adsorption and the associated changes in electronic structures of renewable organic compounds are needed in order to understand the fundamentals behind surface reactions of catalysts for future energies. Using planewave density functional theory (DFT) calculations, the adsorption of ethanol on perfect and O-defected TiO 2 rutile (110) surfaces was examined. On both surfaces the dissociative adsorption mode on five-fold coordinated Ti cations (Ti 4+ 5c) was found to be more favourable than the molecular adsorption mode. On the stoichiometric surface E ads was found to be equal to 0.85 eV for the ethoxide mode and equal to 0.76 eV for the molecular mode. These energies slightly increased when adsorption occurred on the Ti 4+ 5c closest to the O-defected site. However, both considerably increased when adsorption occurred at the removed bridging surface O; interacting with Ti 3+ cations. In this case the dissociative adsorption becomes strongly favoured (E ads = 1.28 eV for molecular adsorption and 2.27 eV for dissociative adsorption). Geometry and electronic structures of adsorbed ethanol were analysed in detail on the stoichiometric surface. Ethanol does not undergo major changes in its structure upon adsorption with its C-O bond rotating nearly freely on the surface. Bonding to surface Ti atoms is a σ type transfer from the O2p of the ethanol-ethoxide species. Both ethanol and ethoxide present potential hole traps on O lone pairs. Charge density and work function analyses also suggest charge transfer from the adsorbate to the surface, in which the dissociative adsorptions show a larger charge transfer than the molecular adsorption mode. This journal is © 2012 the Owner Societies.

  14. First-principles studies on the adsorption of molecular oxygen on Ba(110) surface

    International Nuclear Information System (INIS)

    Li, S.F.; Xue Xinlian; Li Pinglin; Li Xinjian; Jia Yu

    2006-01-01

    The adsorption of O 2 on Ba(110) surface is studied with first-principles calculations based on density functional theory. Our calculations predict that O 2 may prefer to dissociative adsorption on Ba(110) surface without obvious barrier. Also our results do not support the model of charge transfer from the surface to the molecule as a bond breaking mechanism. Instead, the increasing hybridization between O 2 orbitals and the d states of Ba(110) surface may play an important role in the dissociation adsorption

  15. [Dissociative disorders and affective disorders].

    Science.gov (United States)

    Montant, J; Adida, M; Belzeaux, R; Cermolacce, M; Pringuey, D; Da Fonseca, D; Azorin, J-M

    2014-12-01

    The phenomenology of dissociative disorders may be complex and sometimes confusing. We describe here two cases who were initially misdiagnosed. The first case concerned a 61 year-old woman, who was initially diagnosed as an isolated dissociative fugue and was actually suffering from severe major depressive episode. The second case concerned a 55 year-old man, who was suffering from type I bipolar disorder and polyvascular disease, and was initially diagnosed as dissociative fugue in a mooddestabilization context, while it was finally a stroke. Yet dissociative disorders as affective disorder comorbidity are relatively unknown. We made a review on this topic. Dissociative disorders are often studied through psycho-trauma issues. Litterature is rare on affective illness comorbid with dissociative disorders, but highlight the link between bipolar and dissociative disorders. The later comorbidity often refers to an early onset subtype with also comorbid panic and depersonalization-derealization disorder. Besides, unipolar patients suffering from dissociative symptoms have more often cyclothymic affective temperament. Despite the limits of such studies dissociative symptoms-BD association seems to correspond to a clinical reality and further works on this topic may be warranted. Copyright © 2014 L’Encéphale. Published by Elsevier Masson SAS.. All rights reserved.

  16. Multiphoton dissociation of polyatomic molecules

    International Nuclear Information System (INIS)

    Schulz, P.A.

    1979-10-01

    The dynamics of infrared multiphoton excitation and dissociation of SF 6 was investigated under collision free conditions by a crossed laser-molecular beam method. In order to understand the excitation mechanism and to elucidate the requirements of laser intensity and energy fluence, a series of experiments were carried out to measure the dissociation yield dependences on energy fluence, vibrational temperature of SF 6 , the pulse duration of the CO 2 laser and the frequency in both one and two laser experiments. Translational energy distributions of the SF 5 dissociation product measured by time of flight and angular distributions and the dissociation lifetime of excited SF 6 as inferred from the observation of secondary dissociation of SF 5 into SF 4 and F during the laser pulse suggest that the dynamics of dissociation of excited molecules is dominated by complete energy randomization and rapid intramolecular energy transfer on a nanosecond timescale, and can be adequately described by RRKM theory. An improved phenomenological model including the initial intensity dependent excitation, a rate equation describing the absorption and stimulated emission of single photons, and the unimolecular dissociation of excited molecules is constructed based on available experimental results. The model shows that the energy fluence of the laser determines the excitation of molecules in the quasi-continuum and the excess energy with which molecules dissociate after the laser pulse. The role played by the laser intensity in multiphoton dissociation is more significant than just that of overcoming the intensity dependent absorption in the lowest levels. 63 references

  17. Strong-field dissociation dynamics

    International Nuclear Information System (INIS)

    DiMauro, L.F.; Yang, Baorui.

    1993-01-01

    The strong-field dissociation behavior of diatomic molecules is examined under two distinctive physical scenarios. In the first scenario, the dissociation of the isolated hydrogen and deuterium molecular ions is discussed. The dynamics of above-threshold dissociation (ATD) are investigated over a wide range of green and infrared intensities and compared to a dressed-state model. The second situation arises when strong-field neutral dissociation is followed by ionization of the atomic fragments. The study results in a direct measure of the atomic fragment's ac-Stark shift by observing the intensity-dependent shifts in the electron or nuclear fragment kinetic energy. 8 figs., 14 refs

  18. Study of Iodine Prophylaxis Following Nuclear Accidents

    International Nuclear Information System (INIS)

    Sri Widayati; Tedjasari, R. S.; Elfida

    2007-01-01

    Study of iodine prophylaxis following nuclear accidents has been done. Giving stable iodine to a population exposed by I-131 is one of preventive action from internal radiation to the thyroid gland. Stable iodine could be given as Kl tablet in a range of dose of 30 mg/day to 130 mg/day. Improper giving of stable iodine could cause side effect to health, so then some factors should be considered i. e. dose estimation, age, dose of stable iodine to be given, duration of stable iodine prophylaxis and risk of health. (author)

  19. The radiotoxicology of iodine

    International Nuclear Information System (INIS)

    Taylor, D.M.

    1981-01-01

    Thirty radioisotopes of iodine are known but only those with mass numbers from 123 to 135 are of major radiotoxicological interest. Exposure of animals or man to inorganic 131 I or 125 I may result in the induction of benign or malignant thyroid tumors or depression of thyroid function; Bq for Bq 125 I is less toxic than 131 I. However, the shorter lived radioiodines 132 I, 133 I, and 135 I appear to be 10 to 100 times more toxic than 131 I alone. Little information is available about the toxicity of radioiodine containing organic compounds. The DNA precursor, iododeoxyuridine when labelled with 125 I becomes incorporated into the cell nucleus and produces severe and often irreparable damage due to the emission of Auger electrons. The risk estimate for the induction of thyroid carcinoma or adenoma by inorganic 131 I is considered to be 10 to 20x10 -6 persons Gy -1 y -1 , but may be up to 100 times larger for persons exposed to mixtures of short-lived radioiodines. (author)

  20. Dissociative State and Competence

    Directory of Open Access Journals (Sweden)

    Yu-Ju Lin

    2007-10-01

    Full Text Available This report presents the results of forensic evaluation of the civil competence of a case of alleged dissociative identity disorder (DID and discusses whether such dissociative states substantially jeopardize civil competence. A 40-year-old woman claimed that she had had many personalities since her college days. From the age of 37 to 40, she shopped excessively, which left her with millions of dollars of debt. She ascribed her shopping to a certain identity state, over which she had no control. (In this article, we use the term identity state to replace personality as an objective description of a mental state. She thus raised the petition of civil incompetence. During the forensic evaluation, it was found that the identity states were relatively stable and mutually aware of each other. The switch into another identity state was sometimes under voluntary control. The subject showed consistency and continuity in behavioral patterns across the different identity states, and no matter which identity state she was in, there was no evidence of impairment in her factual knowledge of social situations and her capacity for managing personal affairs. We hence concluded that she was civilly competent despite the claimed DID. Considering that the existence and diagnosis of DID are still under dispute and a diagnosis of DID alone is not sufficient to interdict a person's civil right, important clinical and forensic issues remain to be answered.

  1. Hyperglycemia associated dissociative fugue (organic dissociative disorder) in an elderly.

    Science.gov (United States)

    Ram, Dushad; Ashoka, H G; Gowdappa, Basavnna

    2015-01-01

    Inadequate glycemic control in patients with diabetes is known to be associated with psychiatric disorders such as depression, anxiety disorder, and cognitive impairment. However, dissociative syndrome has not been reported so far. Here we are reporting a case of repeated dissociative fugue associated with hyperglycemia, in an elderly with type II diabetes. Possible neurobiological mechanism has been discussed.

  2. Hyperglycemia associated dissociative fugue (organic dissociative disorder) in an elderly

    OpenAIRE

    Ram, Dushad; Ashoka, H. G; Gowdappa, Basavnna

    2015-01-01

    Inadequate glycemic control in patients with diabetes is known to be associated with psychiatric disorders such as depression, anxiety disorder, and cognitive impairment. However, dissociative syndrome has not been reported so far. Here we are reporting a case of repeated dissociative fugue associated with hyperglycemia, in an elderly with type II diabetes. Possible neurobiological mechanism has been discussed.

  3. Hyperglycemia associated dissociative fugue (organic dissociative disorder in an elderly

    Directory of Open Access Journals (Sweden)

    Dushad Ram

    2015-01-01

    Full Text Available Inadequate glycemic control in patients with diabetes is known to be associated with psychiatric disorders such as depression, anxiety disorder, and cognitive impairment. However, dissociative syndrome has not been reported so far. Here we are reporting a case of repeated dissociative fugue associated with hyperglycemia, in an elderly with type II diabetes. Possible neurobiological mechanism has been discussed.

  4. Iodine behaviour in severe accidents

    Energy Technology Data Exchange (ETDEWEB)

    Dutton, L M.C.; Grindon, E; Handy, B J; Sutherland, L [NNC Ltd., Knutsford (United Kingdom); Bruns, W G; Sims, H E [AEA Technology, Harwell (United Kingdom); Dickinson, S [AEA Technology, Winfrith (United Kingdom); Hueber, C; Jacquemain, D [IPSN/CEA, Cadarache, Saint Paul-Lez-Durance (France)

    1996-12-01

    A description is given of analyses which identify which aspects of the modelling and data are most important in evaluating the release of radioactive iodine to the environment following a potential severe accident at a PWR and which identify the major uncertainties which affect that release. Three iodine codes are used namely INSPECT, IODE and IMPAIR, and their predictions are compared with those of the PSA code MAAP. INSPECT is a mechanistic code which models iodine behaviour in the aqueous aerosol, spray water and sump water, and the partitioning of volatile species between the aqueous phases and containment gas space. Organic iodine is not modelled. IODE and IMPAIR are semi-empirical codes which do not model iodine behaviour in the aqueous aerosol, but model organic iodine. The fault sequences addressed are based on analyses for the Sizewell `B` design. Two types of sequence have been analysed.: (a) those in which a major release of fission products from the primary circuit to the containment occur, e.g. a large LOCAS, (b) those where the release by-passes the containment, e.g. a leak into the auxiliary building. In the analysis of the LOCA sequences where the pH of the sump is controlled to be a value of 8 or greater, all three codes predict that the oxidation of iodine to produce gas phase species does not make a significant contribution to the source term due to leakage from the reactor building and that the latter is dominated by iodide in the aerosol. In the case where the pH of the sump is not controlled, it is found that the proportion of gas phase iodine increases significantly, although the cumulative leakage predicted by all three codes is not significantly different from that predicted by MAAP. The radiolytic production of nitric acid could be a major factor in determining the pH, and if the pH were reduced, the codes predict an increase in gas phase iodine species leaked from the containment. (author) 4 figs., 7 tabs., 13 refs.

  5. Dissociation: a developmental psychoneurobiological perspective

    African Journals Online (AJOL)

    Adele

    ... the stream of con- sciousness and memory.1 It is a frequent symptom of a range ... infant for long time spans in an extremely disturbed psycho- biological state that ... Advantage: Dissociation is adaptive in the short-term. Dissociation can be ...

  6. [Assessment of dietary iodine intake of population in non-high-iodine areas in China].

    Science.gov (United States)

    Song, Xiaoyu; Li, Fengqin; Liu, Zhaoping; He, Yuna; Sui, Haixia; Mao, Weifeng; Liu, Sana; Yan, Weixing; Li, Ning; Chen, Junshi

    2011-03-01

    To assess the potential risk of dietary iodine insufficiency of population in non-high-iodine areas (water iodine China. The dietary iodine intake of 13 age-sex population groups were estimated by combining the data of iodine intake from food, table salt and drinking water. Two conditions were considered: consuming iodized salt or non-iodized salt. The data of food and table salt consumption were derived from the Chinese National Nutrition and Health Survey in 2002. Water consumption was calculated as the recommended water intake. Iodine contents of food, table salt and water were calculated from China Food Composition Table and iodine surveillance data. Under the condition of consuming iodized salt, the average iodine intake of all population groups was higher than the Recommended Nutrient Intake (RNI), while the iodine intakes of individuals above Upper Limits (UL) and below RNI were 5.8% and 13.4% respectively, and the iodine intake of individuals lower than the Estimated Average Requirement (EAR) was 9.4% in adults above 18 years of age (including pregnant and lactating women). If non-iodized salt was consumed, the average iodine intake of most sex-age population groups was higher than RNI, but the iodine intake of 97.6% of individuals would be lower than RNI, while the iodine intake of 97.4% of adults would be lower than EAR. The contribution of iodine from table salt was much higher than that from drinking water and food in the condition of consuming iodized salt, while food was the predominant contributor of dietary iodine in the condition of consuming non-iodized salt. The health risk of iodine deficiency was higher than that of iodine excess in areas where water iodine was China, and the risk of iodine insufficiency was much higher if non-iodized salt was consumed. Iodized salt should be the main sources of dietary iodine intake for population in areas where water iodine was China.

  7. Urinary Iodine Concentrations Indicate Iodine Deficiency in Pregnant Thai Women but Iodine Sufficiency in Their School-Aged Children

    NARCIS (Netherlands)

    Gowachirapant, S.; Winichagoon, P.; Wyss, L.; Tong, B.; Baumgartner, J.; Boonstra, A.; Zimmermann, M.B.

    2009-01-01

    The median urinary iodine concentration (UI) in school-aged children is recommended for assessment of iodine nutrition in populations. If the median UI is adequate in school-aged children, it is usually assumed iodine intakes are also adequate in the remaining population, including pregnant women.

  8. Electron stimulated desorption study of oxygen adsorption on tungsten

    International Nuclear Information System (INIS)

    Prince, R.H.; Floyd, G.R.

    1978-01-01

    The adsorption of oxygen on a polycrystalline tungsten surface at approximately 800 K has been studied by means of electron stimulated desorption (ESD). Although precision gas dosing was not employed, the initial sticking probability for dissociative adsorption appears to be essentially unity, while the variation with coverage suggests that a high degree of order exists and that precursor state kinetics are significant. A most noticeable and reproducible discontinuity in ESD parameters occurs at a fractional coverage theta approximately 0.8 (exposure approximately 1.4 X 10 15 molecules/cm 2 incident) which is interpreted as an order-disorder transition within a single (β 1 ) chemisorption state, and results in an increase in the ionic desorption cross-section by a factor of approximately 1.26. A discussion of the adsorption kinetics and the disorder transition is given in terms of current models of dissociative adsoption which include the effects of nearest neighbour lateral interactions. (Auth.)

  9. Iodinated contrast media nephrotoxicity

    International Nuclear Information System (INIS)

    Meyrier, A.

    1994-01-01

    In the late seventies, iodinated contrast agents (ICA) were considered to be a major cause of acute iatrogenic renal failure. Over the last decade new contrast agents have been synthesized, nonionic and less hyperosmolar. The incidence of acute renal failure due to ICAs, varies from 3.7 to 70% of cases according to the series, with an average figure of 10.2%. The pathophysiology of ICA nephrotoxicity was mainly studied in laboratory animal models. Three main factors are involved in an inducing ICA-mediated decrease in glomerular filtration rate: reduction of the renal plasma flow, a direct cytotoxic effect on renal tubular cells and erythrocyte alteration leading to intra-renal sludge. Excluding dysglobulinemias with urinary excretion of immunoglobulin light chains, which represent a special case of maximum nephrotoxicity, 4 main risk factors of renal toxicity have been identified in nondiabetic subjects: previous renal failure with serum creatinine levels greater than 140 μmol per liter, extracellular dehydration, age over 60 and use of high doses of ICA and/or repeated ICA injections before serum creatinine levels return to baseline. Preventive measures for avoiding ICA nephrotoxicity are threefold: maintain or restore adequate hydration with saline infusion, stop NSAID treatment several days before ICA administration, and allow a 5 day interval before repeating contrast media injections. New, nonionic and moderately hyperosmolar contrast agents appear to be much less nephrotoxic than conventional ICAs in laboratory animals and in high-risk patients. It is advisable to select such contrast media for investigating high-risk patients. This approach was recently substantiated in well designed, randomized clinical studies which included more than 2 000 patients. (author)

  10. Experimental reproduction of iodine deficiency in cattle.

    Science.gov (United States)

    McCoy, M A; Smyth, J A; Ellis, W A; Arthur, J R; Kennedy, D G

    1997-11-22

    The role of iodine deficiency in stillbirth/perinatal weak calf syndrome was investigated in pregnant heifers. Five heifers were fed an iodine deficient diet (mean [sd] iodine concentration 0.06 [0.01] mg/kg dry matter [DM]) and six received an iodine sufficient diet (mean [sd] iodine concentration 1.45 [0.27] mg/kg DM). The diets consisted of wheat and soyabean meal with added minerals and vitamins (with or without iodine) and were fed to the heifers over the final four to five months of pregnancy. The iodine deficient diet produced clinicopathological changes and pathological changes in the thyroid glands of both the heifers and their offspring. However, all the calves in the iodine deficient group were born clinically normal.

  11. Thyroid disorders in mild iodine deficiency

    DEFF Research Database (Denmark)

    Laurberg, P; Nøhr, S B; Pedersen, K M

    2000-01-01

    Comparative epidemiologic studies in areas with low and high iodine intake and controlled studies of iodine supplementation have demonstrated that the major consequence of mild-to-moderate iodine deficiency for the health of the population is an extraordinarily high occurrence of hyperthyroidism...... endangered but the consequences of severe iodine deficiency for brain development are grave and a considerable safety margin is advisable. Moreover, a shift toward less malignant types of thyroid cancer and a lower radiation dose to the thyroid in case of nuclear fallout support that mild-to-moderate iodine...... deficiency should be corrected. However, there is evidence that a high iodine intake may be associated with more autoimmune hypothyroidism, and that Graves' disease may manifest at a younger age and be more difficult to treat. Hence, the iodine intake should be brought to a level at which iodine deficiency...

  12. Effect of iodine solutions on polyaniline films

    International Nuclear Information System (INIS)

    Ayad, M.M.; Amer, W.A.; Stejskal, J.

    2009-01-01

    Polyaniline (PANI) emeraldine-base films have been exposed to iodine solutions. The interaction between the films and the iodine solution was studied using the quartz-crystal microbalance (QCM) technique and the UV-visible absorption spectroscopy. The iodine-treated film of emeraldine base was subjected to dedoping process using 0.1 M ammonia solution. The resulting film was exposed again to the previously used iodine solution. Iodine was found to play multiple roles: the ring-iodination of PANI film, the oxidation of PANI to pernigraniline base, and iodine doping to PANI salt. A sensor based on PANI-coated electrode of QCM was developed to monitor the presence of iodine in solution.

  13. Waved graphene: Unique structure for the adsorption of small molecules

    International Nuclear Information System (INIS)

    Pan, Hui

    2017-01-01

    We propose waved graphenes for the strong adsorption of molecules and investigate their potential applications. We find that the physical adsorption of molecules on waved graphene is greatly enhanced by compression. At optimal compression, the physical adsorption energies of H_2, N_2, NO, and CO are increased by 6–9 times, and that for O_2 is more than 2 times. We show that the energy for their chemical adsorption on waved graphene decreases dramatically with the increment of compression. The energy of dissociation of H_2 on flat graphene is 1.63 eV and reduced to 0.06 eV (96% reduction) on waved graphene at a compression of 50%, respectively. The energy for chemical adsorption of O_2 on waved graphenes is extremely reduced from 0.98 eV to −0.57 eV as with compression increasing from 0 to 50%, indicating the transition of endothermic chemical adsorption to exothermic. We further show that the electronic properties of waved graphenes are modified, leading to the change of electrical characters. We see that the waved graphenes may find applications in gas storage, sensor and catalyst because of enhanced physical and chemical adsorption and the induced change of electronic properties. - Highlights: • Adsorption of small molecules on waved graphene is greatly enhanced. • Strong physical adsorption in the trough of waved graphene can be achieved by tuning the curvature. • Chemical adsorption is on the crest of waved graphene. • Exothermic dissociation of H2 and O2 can be realized on waved graphene under high compression. • Wave graphene can be candidates as catalysts and gas storage/sensor.

  14. Waved graphene: Unique structure for the adsorption of small molecules

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Hui, E-mail: huipan@umac.mo

    2017-03-01

    We propose waved graphenes for the strong adsorption of molecules and investigate their potential applications. We find that the physical adsorption of molecules on waved graphene is greatly enhanced by compression. At optimal compression, the physical adsorption energies of H{sub 2}, N{sub 2}, NO, and CO are increased by 6–9 times, and that for O{sub 2} is more than 2 times. We show that the energy for their chemical adsorption on waved graphene decreases dramatically with the increment of compression. The energy of dissociation of H{sub 2} on flat graphene is 1.63 eV and reduced to 0.06 eV (96% reduction) on waved graphene at a compression of 50%, respectively. The energy for chemical adsorption of O{sub 2} on waved graphenes is extremely reduced from 0.98 eV to −0.57 eV as with compression increasing from 0 to 50%, indicating the transition of endothermic chemical adsorption to exothermic. We further show that the electronic properties of waved graphenes are modified, leading to the change of electrical characters. We see that the waved graphenes may find applications in gas storage, sensor and catalyst because of enhanced physical and chemical adsorption and the induced change of electronic properties. - Highlights: • Adsorption of small molecules on waved graphene is greatly enhanced. • Strong physical adsorption in the trough of waved graphene can be achieved by tuning the curvature. • Chemical adsorption is on the crest of waved graphene. • Exothermic dissociation of H2 and O2 can be realized on waved graphene under high compression. • Wave graphene can be candidates as catalysts and gas storage/sensor.

  15. Dissociative recombination of dications

    International Nuclear Information System (INIS)

    Seiersen, K.; Heber, O.; Jensen, M.J.; Safvan, C.P.; Andersen, L. H.

    2003-01-01

    Dissociative recombination (DR) of doubly-charged positive ions has been studied at the heavy ion storage ring ASTRID. Low-energy electrons were scattered on the dication of the N 2 molecule, and the absolute cross section was measured in the energy range of 10 -4 -50 eV. From the measured cross section, a thermal rate coefficient of 5.8x10 -7 cm 3 s -1 at 300 K was extracted. Furthermore, we present new results on the CO 2+ DR rate, and a summary and comparison of measured DR rate coefficients for both the singly and doubly-charged ions of CO, CO 2 , and N 2 is presented

  16. Quarkonium dissociation by anisotropy

    Science.gov (United States)

    Chernicoff, Mariano; Fernández, Daniel; Mateos, David; Trancanelli, Diego

    2013-01-01

    We compute the screening length for quarkonium mesons moving through an anisotropic, strongly coupled mathcal{N} = 4 super Yang-Mills plasma by means of its gravity dual. We present the results for arbitrary velocities and orientations of the mesons, as well as for arbitrary values of the anisotropy. The anisotropic screening length can be larger or smaller than the isotropic one, and this depends on whether the comparison is made at equal temperatures or at equal entropy densities. For generic motion we find that: (i) mesons dissociate above a certain critical value of the anisotropy, even at zero temperature; (ii) there is a limiting velocity for mesons in the plasma, even at zero temperature; (iii) in the ultra-relativistic limit the screening length scales as (1 - v 2)ɛ with ɛ = 1 /2, in contrast with the isotropic result ɛ = 1 /4.

  17. Dissociation - a preliminary contextual model

    Directory of Open Access Journals (Sweden)

    C Krüger

    2007-02-01

    Full Text Available Background. The Diagnostic and Statistical Manual of Mental Disorders (DSM system has certain limitations when applied to two South African examples of dissociation, because it is descriptive (non-explanatory and focuses on intrapsychic (non-communal processes. Even the existing Western explanatory models of dissociation fail to accommodate fully the communal aspects of dissociation in our South African context. Objectives and methods. The aim was to explore an expanded perspective on dissociation that does not limit it to an intrapsychic phenomenon, but that accounts for the interrelatedness of individuals within their social context. Auto-ethnography was used. In this article a collective, socially orientated, contextual hermeneutic was applied to two local examples of dissociation. Three existing Western models were expanded along multicontextual, collective lines, for them to be more useful in the pluralistic South African context. Results. This preliminary contextual model of dissociation includes a person’s interpersonal, socio-cultural, and spiritual contexts, in addition to the intrapsychic context. Dissociation is considered to be a normal information-processing tool that maintains balanced, coherent selves-in-society, i.e. individuals connected to each other. In the South African context dissociation appears mostly as a normal phenomenon and seldom as a sign of mental illness. Dissociation is pivotal for the normal construction of individual and communal identities in the face of conflicting sets of information from various contexts. Dissociation may help individuals or communities to survive in a world of conflicting messages, where conflict is often interpersonal/cultural/societal in nature, rather than primarily intrapsychic. Conclusions. This model should be developed and evaluated further. Such evaluation would require suitable new local terminology.

  18. Contrast induced hyperthyroidism due to iodine excess

    OpenAIRE

    Mushtaq, Usman; Price, Timothy; Laddipeerla, Narsing; Townsend, Amanda; Broadbridge, Vy

    2009-01-01

    Iodine induced hyperthyroidism is a thyrotoxic condition caused by exposure to excessive iodine. Historically this type of hyperthyroidism has been described in areas of iodine deficiency. With advances in medicine, iodine induced hyperthyroidism has been observed following the use of drugs containing iodine—for example, amiodarone, and contrast agents used in radiological imaging. In elderly patients it is frequently difficult to diagnose and control contrast related hyperthyroidism, as most...

  19. Formation and behaviour of organic iodine

    International Nuclear Information System (INIS)

    Zilliacus, R.; Koukkar, P.; Karjunen, T.; Sjoevall, H.

    2002-01-01

    The report presents experimental studies on the formation of organic iodine in severe reactor accidents. The analyses were performed to evaluate the amount of alkaline chemical needed for effective pH control of containment water during the accidents. The formation of organic iodine in solutions used in the filtered venting system and the absorption of iodine compounds in the solutions were studied. Experiments for the formation of organic iodine on painted surfaces were also performed. (au)

  20. Mineral resource of the month: iodine

    Science.gov (United States)

    Polyak, Désirée E.

    2009-01-01

    The article focuses on iodine, its benefits and adverse effects, and its production and consumption. It states that iodine is essential to humans for it produces thyroid hormones to nourish thyroid glands but excessive intake could cause goiter, hyperthyroidism or hypothyroidism. U.S. laws require salt iodization to help prevent diseases. Chile and Japan are the world's leading iodine producer while in the U.S. iodine is mined from deep well brines in northern Oklahoma.

  1. Iodine Prophylaxis and Nuclear Accidents

    International Nuclear Information System (INIS)

    Franic, Z.

    1998-01-01

    Iodine is a highly volatile element therefore being very mobile in the environment. It enters the metabolism of living organisms and is selectively taken up and concentrated in the thyroid gland. The plume (cloud-like formation) of radioactive material that might be released in the environment in the case of a serious nuclear accident, primarily consists of the radioactive isotopes of iodine. Among those, due to its decay properties, is the most important 131 I. The effective means of protecting the thyroid gland against exposure to radioactive iodine is an intake of stable iodine. Therefore, one of the central issues in the emergency planning is to determine whether and at which projected thyroid radiation dose stable iodine should be given to the population. The International Atomic Energy Agency (IAEA) set the generic optimized intervention value for iodine prophylaxis to 100 mGy of avertable committed dose to a thyroid.The prophylaxis is implemented by utilizing the pills of pills of potassium iodine (KI). The efficacy of KI in protecting the thyroid gland depends upon the time of intake relative to the start of exposure to radioactive iodine. The best results are obtained if KI is taken 1-2 hours before or immediately after the start of exposure. The recommended dosage, based upon the study performed by Il'in et.al. is 130 mg/day. KI should be taken at least three days after the acute exposure to radioiodine, to prevent accumulation in a thyroid gland of radioiodine excreted from the other compartments of the body. The largest epidemiological study on the effects of KI prophylaxis ever performed was the one in Poland after the Chernobyl accident. Stable iodine was given as single dose of KI solution to 10.5 million of children and 7 millions of adults. Among children no serious side effects were seen while only two adults (with previously recorded iodine sensitivity) had severe respiratory distresses. Polish experiences showed that rapid response to such

  2. Management modes for iodine-129

    International Nuclear Information System (INIS)

    White, I.F.; Smith, G.M.

    1984-01-01

    This study completes a two-stage programme, supported by the Commission of the European Communities, on management modes for iodine-129. The models for the radiological assessment of iodine-129 management modes have been reviewed and, where necessary, revised, and a generic radiological assessment has been carried out using these models. Cost benefit analysis has been demonstrated for a variety of iodine-129 management modes; for a wide range of assumptions, the costs of abatement of atmospheric discharges would be outweighed by the radiological benefits. The cost benefit analysis thus complements and confirms the preliminary conclusion of the previous study: iodine-129 should be trapped to a large extent from the off-gases of a large reprocessing plant and disposed of by other suitable means, in order to ensure that all exposures from this radionuclide are as low as reasonably achievable. Once the major fraction of the iodine-129 throughput of a reprocessing plant has been trapped from the dissolver off-gases, there are unlikely to be strong radiation protection incentives either for further trapping from the dissolver off-gases or for trapping from the vessel off-gases. In a generic study it is not possible to state an optimum choice of process(es) for abatement of atmospheric discharges of iodine-129. This choice must be determined by assessments in the specific context of a particular reprocessing plant, its site, the waste disposal routes that are actually available, and also in the wider context of the management plans for all radioactive wastes at the plant in question

  3. The importance of iodine nutrition during pregnancy.

    Science.gov (United States)

    Glinoer, Daniel

    2007-12-01

    To examine the importance of iodine nutrition during pregnancy. Review of existing literature of iodine in pregnancy. Population surveys and metabolic studies. Pregnant women. The main changes in thyroid function associated with pregnancy are due to an increase in hormone requirements that begin in the first trimester of gestation. This increase can only be met by a proportional increase in hormone production, something that depends directly upon the availability of iodine. When dietary iodine is lacking, an adequate physiological adaptation is difficult to achieve and is progressively replaced by pathological alterations that occur in parallel with the degree and duration of iodine deprivation. Iodine prophylaxis should be given systematically to women during pregnancy. In most public health programmes dealing with the correction of iodine deficiency disorders, iodised salt has been used as the preferred means to deliver iodine to households. Iodised salt, however, is not the ideal means of delivering iodine in the specific instances of pregnancy, breast-feeding and complementary feeding because of the need to limit salt intake during these periods. In European countries, presently it is proposed that iodine is given to pregnant women and breast-feeding mothers by systematically administering multivitamin tablets containing iodine in order to reach the recommended dietary allowance of 250 microg iodine day-1.

  4. Iodine in Enteral and Parenteral Nutrition

    NARCIS (Netherlands)

    Zimmermann, M.B.; Crill, C.M.

    2010-01-01

    Iodine deficiency (ID) has multiple adverse effects on growth and development due to inadequate thyroid hormone production. Methods for assessment of iodine nutrition in individuals include the urinary iodine concentration (UI), thyroid size and thyroid function tests. The UI measured in several

  5. Industrial system for producing iodine-123

    International Nuclear Information System (INIS)

    Brantley, J.C.

    1985-01-01

    An industrial system to produce iodine-123 required a complex set of steps involving new approaches by the Food and Drug Administration, difficult distribution procedures, and evidence from potential users that either very pure iodine-123 or inexpensive iodine-123 is needed. Industry has shown its willingness to invest in new radionuclides but needs strong evidence as to product potential to justify those investments

  6. Iodine excretion in school children in Copenhagen

    DEFF Research Database (Denmark)

    Rasmussen, Lone B; Kirkegaard-Klitbo, Ditte Marie; Laurberg, Peter

    2016-01-01

    INTRODUCTION: Studies of dietary habits show a high iodine intake in children in Denmark. Iodine excretion in children has not previously been assessed. Iodine excretion in adults is below the recommended threshold, and it is therefore being discussed to increase the fortification level. The main...

  7. MARGINAL IODINE DEFICIENCY EXACERBATES PERCHLORATE THYROID TOXICITY.

    Science.gov (United States)

    The environmental contaminant perchlorate disrupts thyroid homeostasis via inhibition of iodine uptake into the thyroid. This work tested whether iodine deficiency exacerbates the effects of perchlorate. Female 27 day-old LE rats were fed a custom iodine deficient diet with 0, 50...

  8. Chemical species of iodine in some seaweeds. Pt. 2. Iodine-bound biological macromolecules

    International Nuclear Information System (INIS)

    Xiaolin Hou; Chifang Chai; Xiaojun Yan

    2000-01-01

    The distribution of iodine in various biological macromolecules in Sargassum kjellmanianum was studied using neutron activation analysis combined with chemical and biochemical separation techniques. The results indicate that iodine is mainly bound with protein, part of iodine with pigment and polyphenol, and little with polysaccharides, such as algin, fucoidan and cellulose. This result is significant for the mechanism of enriching iodine of algae and utilization of alga iodine. (author)

  9. Prediction of iodide adsorption on oxides by surface complexation modeling with spectroscopic confirmation.

    Science.gov (United States)

    Nagata, Takahiro; Fukushi, Keisuke; Takahashi, Yoshio

    2009-04-15

    A deficiency in environmental iodine can cause a number of health problems. Understanding how iodine is sequestered by materials is helpful for evaluating and developing methods for minimizing human health effects related to iodine. In addition, (129)I is considered to be strategically important for safety assessment of underground radioactive waste disposal. To assess the long-term stability of disposed radioactive waste, an understanding of (129)I adsorption on geologic materials is essential. Therefore, the adsorption of I(-) on naturally occurring oxides is of environmental concern. The surface charges of hydrous ferric oxide (HFO) in NaI electrolyte solutions were measured by potentiometric acid-base titration. The surface charge data were analyzed by means of an extended triple-layer model (ETLM) for surface complexation modeling to obtain the I(-) adsorption reaction and its equilibrium constant. The adsorption of I(-) was determined to be an outer-sphere process from ETLM analysis, which was consistent with independent X-ray absorption near-edge structure (XANES) observation of I(-) adsorbed on HFO. The adsorption equilibrium constants for I(-) on beta-TiO(2) and gamma-Al(2)O(3) were also evaluated by analyzing the surface charge data of these oxides in NaI solution as reported in the literature. Comparison of these adsorption equilibrium constants for HFO, beta-TiO(2), and gamma-Al(2)O(3) based on site-occupancy standard states permitted prediction of I(-) adsorption equilibrium constants for all oxides by means of the Born solvation theory. The batch adsorption data for I(-) on HFO and amorphous aluminum oxide were reasonably reproduced by ETLM with the predicted equilibrium constants, confirming the validity of the present approach. Using the predicted adsorption equilibrium constants, we calculated distribution coefficient (K(d)) values for I(-) adsorption on common soil minerals as a function of pH and ionic strength.

  10. Dissociative symptomatology in cancer patients

    Science.gov (United States)

    Civilotti, Cristina; Castelli, Lorys; Binaschi, Luca; Cussino, Martina; Tesio, Valentina; Di Fini, Giulia; Veglia, Fabio; Torta, Riccardo

    2015-01-01

    Introduction: The utilization of the post-traumatic stress disorder (PTSD) diagnostic spectrum is currently being debated to categorize psychological adjustment in cancer patients. The aims of this study were to: (1) evaluate the presence of cancer-related traumatic dissociative symptomatology in a sample of cancer patients; (2) examine the correlation of cancer-related dissociation and sociodemographic and medical variables, anxiety, depression, and post-traumatic stress symptomatology; (3) investigate the predictors of cancer-related dissociation. Methods: Ninety-two mixed cancer patients (mean age: 58.94, ds = 10.13) recruited from two hospitals in northern Italy were administered a questionnaire on sociodemographic and medical characteristics, the Karnofsky Scale to measure the level of patient activity and medical care requirements, the Hospital Anxiety and Depression Scale (HADS) to evaluate the presence of anxiety and depression, the Impact of Event Scale Revised (IES-R) to assess the severity of intrusion, avoidance, and hypervigilance, and the Peritraumatic Dissociative Experiences Questionnaire (PDEQ) to quantify the traumatic dissociative symptomatology. Results: 31.5% of participants report a PDEQ score above the cutoff. The results indicated that dissociative symptomatology was positively correlated with HADS scores (HADS-Anxiety: r = 0.476, p dissociative symptomatology. The results converged on a three predictor model revealing that IES-R-Intrusion, IES-R-Avoidance, and IES-R-Hyperarousal accounted for 53.9% of the explained variance. Conclusion: These findings allow us to hypothesize a specific psychological reaction which may be ascribed to the traumatic spectrum within the context of cancer, emphasizing the close relationship between the origin of dissociative constituents which, according to the scientific literature, compose the traumatic experience. Our results have implications for understanding dissociative symptomatology in a cancer

  11. Probing the active sites for CO dissociation on ruthenium nanoparticles

    DEFF Research Database (Denmark)

    Strebel, Christian Ejersbo; Murphy, Shane; Nielsen, Rasmus Munksgård

    2012-01-01

    affect the CO dissociation activity. The Ru nanoparticles were synthesized in a UHV chamber by gas-aggregation magnetron sputtering in the size range from 3 to 15 nm and the morphology was investigated in situ by scanning tunneling microscopy and ex situ by high resolution transmission electron...... microscopy. Surprisingly, it was found that larger particles were more active per surface area for CO dissociation. It is suggested that this is due to larger particles exposing a more rough surface than the smaller particles, giving rise to a higher relative amount of under-coordinated adsorption sites...... on the larger particles. The induced surface roughness is proposed to be a consequence of the growth processes in the gas-aggregation chamber....

  12. Study on adsorption behavior of radioiodine gas using incense stick aerosol

    International Nuclear Information System (INIS)

    Murata, Mikio; Noguchi, Hiroshi; Kato, Shohei; Kokubu, Morinobu

    1987-01-01

    Adsorption of radioactive elemental iodine gas ( 131 I 2 ) on incense stick aerosol particles has been studied to provide basic data for a realistic and precise assessment of dose to the public due to radioiodine released from nuclear facilities. A mixture of iodine gas and aerosol was passed once through a glass vessel to cause the adsorption reaction. The adsorption was studied at different reaction times, initial I 2 gas concentrations and particle number concentrations. The results showed that the adsorption reached an equilibrium in about 2 min at the initial I 2 gas concentration of 10 -10 g/cm 3 . The proportion of iodine adsorbed by the aerosol particles was almost constant, about 25 % at the initial I 2 gas concentrations below 10 -11 g/cm 3 and at the reaction time of 1 min, and decreased with increase of the initial concentration over 10 -11 g/cm 3 . The adsorption isotherm of the aerosol for the gas was obtained from the experimental data. The semi-empirical equations to explain the adsorption reaction were also obtained based on the experimental data and the FUCHS's equation relating to vaporization of a droplet. The sticking probability in the equations was estimated to be 7.6 x 10 -3 . The calculated results using the equations were in good agreement with the experimental ones. (author)

  13. Transfer of gaseous iodine to Tradescantia

    International Nuclear Information System (INIS)

    Nakamura, Yuji; Ohmomo, Yoichiro.

    1984-01-01

    Transfer rates of gaseous elemental iodine and methyliodide from atmosphere to Tradescantia were investigated in relation to supposed genetic mutation due to radioactive iodine released from nuclear facilities. The estimated transfer rate of elemental iodine to the young buds of Tradescantia, which was given as the ratio of iodine uptake rate per unit weight of the plant to the concentration of the element in the air, was approximately 7 x 10 -2 cm 3 /g.sec, about 30 to 40 times higher than that of methyliodide. The contribution of direct deposition of elemental iodine was suggested to be significant, although methyliodide was mainly absorbed by respiration through stomata of the plant. (author)

  14. Water on TiO2 studied by work function change: adsorption in cycles

    International Nuclear Information System (INIS)

    Bundaleski, Nenad; Silva, Ana G; Jean-Shaw, Bobbie; Teodoro, Orlando; Moutinho, Augusto

    2013-01-01

    The nature of water adsorption on TiO 2 (110) rutile surface attracts a lot of attention for quite some time. In spite of the considerable experimental and theoretical efforts a lot of details remain unclear. We have been using work function study to follow the adsorption of water on TiO 2 at room temperature, and interpreted the results in terms of fast dissociative adsorption on bridging oxygen vacancies (BOV) and much slower non-dissociative adsorption on Ti 5f rows. Additionally, we concluded that water from Ti 5f rows efficiently desorbs at room temperature which is not the case for BOV adsorption sites. Here we propose a novel experimental approach which consists of monitoring in real-time the work function change during cycles of water adsorption. Since desorption at BOVs does not take place at room temperature, this method allows us to resolve the adsorption dynamics on the two adsorption sites. The first results changed our understanding of the phenomenon: we show that both, adsorption on BOVs and Ti 5f are both very fast. Additionally, slow exponential decay of the work function is observed, which is not directly related to water adsorption. The possible explanation of the third slow contribution could be related to the migration of hydrogen atoms along the bridging oxygen rows.

  15. Dietary flavonoids and iodine Metabolism

    NARCIS (Netherlands)

    Elst, van der J.P.; Smit, J.W.A.; Romijn, H.A.; Heide, van der D.

    2003-01-01

    Flavonoids have inhibiting effects on the proliferation of cancer cells, including thyroidal ones. In the treatment of thyroid cancer the uptake of iodide is essential. Flavonoids are known to interfere with iodide organification ill vitro, and to cause goiter. The influence of flavonoids on iodine

  16. Dissociative absorption: An empirically unique, clinically relevant, dissociative factor.

    Science.gov (United States)

    Soffer-Dudek, Nirit; Lassri, Dana; Soffer-Dudek, Nir; Shahar, Golan

    2015-11-01

    Research of dissociative absorption has raised two questions: (a) Is absorption a unique dissociative factor within a three-factor structure, or a part of one general dissociative factor? Even when three factors are found, the specificity of the absorption factor is questionable. (b) Is absorption implicated in psychopathology? Although commonly viewed as "non-clinical" dissociation, absorption was recently hypothesized to be specifically associated with obsessive-compulsive symptoms. To address these questions, we conducted exploratory and confirmatory factor analyses on 679 undergraduates. Analyses supported the three-factor model, and a "purified" absorption scale was extracted from the original inclusive absorption factor. The purified scale predicted several psychopathology scales. As hypothesized, absorption was a stronger predictor of obsessive-compulsive symptoms than of general psychopathology. In addition, absorption was the only dissociative scale that longitudinally predicted obsessive-compulsive symptoms. We conclude that absorption is a unique and clinically relevant dissociative tendency that is particularly meaningful to obsessive-compulsive symptoms. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Thyroid disorders in mild iodine deficiency.

    Science.gov (United States)

    Laurberg, P; Nøhr, S B; Pedersen, K M; Hreidarsson, A B; Andersen, S; Bülow Pedersen, I; Knudsen, N; Perrild, H; Jørgensen, T; Ovesen, L

    2000-11-01

    Comparative epidemiologic studies in areas with low and high iodine intake and controlled studies of iodine supplementation have demonstrated that the major consequence of mild-to-moderate iodine deficiency for the health of the population is an extraordinarily high occurrence of hyperthyroidism in elderly subjects, especially women, with risk of cardiac arrhythmias, osteoporosis, and muscle wasting. The hyperthyroidism is caused by autonomous nodular growth and function of the thyroid gland and it is accompanied by a high frequency of goiter. Pregnant women and small children are not immediately endangered but the consequences of severe iodine deficiency for brain development are grave and a considerable safety margin is advisable. Moreover, a shift toward less malignant types of thyroid cancer and a lower radiation dose to the thyroid in case of nuclear fallout support that mild-to-moderate iodine deficiency should be corrected. However, there is evidence that a high iodine intake may be associated with more autoimmune hypothyroidism, and that Graves' disease may manifest at a younger age and be more difficult to treat. Hence, the iodine intake should be brought to a level at which iodine deficiency disorders are avoided but not higher. Iodine supplementation programs should aim at relatively uniform iodine intake, avoiding deficient or excessive iodine intake in subpopulations. To adopt such a strategy, surveillance programs are needed.

  18. Iodine tablets and a nuclear accident

    International Nuclear Information System (INIS)

    Paile, W.

    1992-01-01

    Radioactive iodine is one of the major substances released during severe nuclear accidents. Radioactive iodine is easily gasified, and if present in fallout it can enter the lungs, and thereby the circulatory system, with the inhalation of air. Once in a body, radioactive iodine accumulates in the thyroid and may result in tumours in the thyroid and, in extreme cases, impaired thyroid function. Accumulation of radioactive iodine can be prevented by taking non-radioactive, 'cold' iodine as tablets. Iodine tablets dilute the radioactive iodine that has entered the body. A dose of iodine also paralyses the thyroid temporarily by saturating its iodine-carrying capacity. To be useful iodine tablets should be taken immediately when a radioactive emission has occurred. If the tablets are taken too early or too late, they give little protection. Iodine tablets should not be taken just to be on the safe side, since their use may involve harmful side effects. Dosing instructions should also be followed with care. (orig.)

  19. Iodine removing method in organic solvent

    International Nuclear Information System (INIS)

    Suzuki, Takeo; Sakurai, Manabu

    1988-01-01

    Purpose: To effectively remove iodine in an organic solvent to thereby remove iodine in the solvent that can be re-used or put to purning treatment. Method: Organic solvent formed from wastes of nuclear facilities is mixed with basic lead acetate, or silica gel or activated carbon incorporated with such a compound to adsorb iodine in the organic solvent to the basic lead acetate. Then, iodine in the organic solvent is removed by separating to eliminate the basic lead acetate adsorbing iodine from the organic solvent or by passing the organic solvent through a tower or column charged or pre-coated with silica gel or activated carbon incorporated with lead acetate. By using basic lead acetate as the adsorbents, iodine can effective by adsorbed and eliminated. Thus, the possibility of circumstantial release of iodine can be reduced upon reusing or burning treatment of the organic solvent. (Kamimura, M.)

  20. Prophylactic iodine treatment in radiation protection

    International Nuclear Information System (INIS)

    Oberhausen, E.

    1980-01-01

    Prophylactic iodine treatment is to prevent accumulation of radioactive iodine in the thyroid. This is done by administering a large amount of stable iodine before uptake of radioactive iodine so that further accummulation of iodine in the thyroid will be impossible. This blocking effect should be as complete as possible. This is achieved by administering an initial dose of 200 mg potassium iodide. As the release of radioactive iodine may last several hours or even days; for this reason, maintenance doses of 100 mg potassium iodide should be administered in 8-hour intervals. The risk of prophylactiv iodine treatment is rather low; however, provocation of latent hyperthyreoses must be expected in, at the most, 0.2% of the exposed population. (orig./MG) [de

  1. Photo-electron spectroscopy using synchrotron radiation of molecular radicals and fragments produced by laser photo-dissociation

    International Nuclear Information System (INIS)

    Nahon, Laurent

    1991-01-01

    This research thesis reports the combined use of a laser and of a synchrotron radiation in order to respectively photo-dissociate a molecule and to photo-ionize fragments which are analysed by photo-electron spectroscopy. This association allows, on the one hand, radical photo-ionization to be studied, and, on the other hand, polyatomic molecule photo-dissociation to be studied. The author studied the photo-excitation and/or photo-ionization in layer 4d (resp. 3d) of atomic iodine (resp. bromine) produced almost complete laser photo-dissociation of I_2 (resp. Br_2). He discuses the processes of relaxation of transitions from valence 4d to 5p (resp. 3d to 4p) which occur either by direct self-ionization or by resonant Auger effect, and reports the study of photo-dissociation of s-tetrazine (C_2N_4H_2) [fr

  2. Kinetics of an oxygen – iodine active medium with iodine atoms optically pumped on the {sup 2}P{sub 1/2} – {sup 2}P{sub 3/2} transition

    Energy Technology Data Exchange (ETDEWEB)

    Zagidullin, M V; Azyazov, V N [Samara Branch of the P.N. Lebedev Physical Institute, Russian Academy of Sciences, Samara (Russian Federation); Malyshev, M S [S.P. Korolev Samara State Aerospace University, Samara (Russian Federation)

    2015-08-31

    The kinetics of the processes occurring in an O{sub 2} – I{sub 2} – He – H{sub 2}O gas flow in which photodissociation of molecular iodine at a wavelength close to 500 nm and excitation of atomic iodine on the {sup 2}P{sub 1/2} – {sup 2}P{sub 3/2} transition by narrow-band radiation near 1315 nm are implemented successively has been analysed. It is shown that implementation of these processes allows one to form an oxygen – iodine medium with a high degree of dissociation of molecular iodine and a relative content of singlet oxygen O{sub 2}(a{sup 1}Δ) exceeding 10%. Having formed a supersonic gas flow with a temperature ∼100 K from this medium, one can reach a small-signal gain of about 10{sup -2} cm{sup -1} on the {sup 2}P{sub 1/2} – {sup 2}P{sub 3/2} transition in iodine atoms. The specific power per unit flow cross section in the oxygen – iodine laser with this active medium may reach ∼100 W cm{sup -2}. (active media)

  3. Iodine status in neonates in Denmark: regional variations and dependency on maternal iodine supplementation

    DEFF Research Database (Denmark)

    Nøhr, S B; Laurberg, P; Børlum, K G

    1994-01-01

    Iodine status of 147 neonates born in five different regions of Denmark was evaluated in relation to the iodine content of breast milk and iodine supplementation taken by the mother. Approximately two-thirds of the women had not received iodine supplementation. They had low iodine concentrations...... in breast milk and urinary iodine concentrations of the neonates at day 5 were low. The median values (milk/urine) were 33.6/31.7 micrograms/l (Randers 22/26, Ringkøbing 29/16, Aalborg 36/31. Arhus 54/41 and Copenhagen 55/59 micrograms/l). Higher values were found in the group where tablets containing...... iodine had been taken (milk/urine: 57.0/61.0 micrograms/l). In general, the values are low compared with internationally recommended levels. We suggest that mothers without autoimmune thyroid disease should receive iodine supplementation in the form of vitamin/mineral tablets containing iodine (150...

  4. Dissociation Energies of Diatomic Molecules

    International Nuclear Information System (INIS)

    Qun-Chao, Fan; Wei-Guo, Sun

    2008-01-01

    Molecular dissociation energies of 10 electronic states of alkali molecules of KH, 7 LiD, 7 LiH, 6 LiH, NaK, NaLi and NaRb are studied using the highest three accurate vibrational energies of each electronic state, and an improved parameter-free analytical formula which is obtained starting from the LeRoy–Bernstein vibrational energy expression near the dissociation limit. The results show that as long as the highest three vibrational energies are accurate, the current analytical formula will give accurate theoretical dissociation energies D e theory , which are in excellent agreement with the experimental dissociation energies D e expt . (atomic and molecular physics)

  5. Neural complexity, dissociation, and schizophrenia

    Czech Academy of Sciences Publication Activity Database

    Bob, P.; Šusta, M.; Chládek, Jan; Glaslová, K.; Fedor-Ferybergh, P.

    2007-01-01

    Roč. 13, č. 10 (2007), HY1-5 ISSN 1234-1010 Institutional research plan: CEZ:AV0Z20650511 Keywords : neural complexity * dissociation * schizophrenia Subject RIV: FH - Neurology Impact factor: 1.607, year: 2007

  6. Dissociative Tendencies and Traffic Incidents

    Directory of Open Access Journals (Sweden)

    Valle, Virginia

    2012-01-01

    Full Text Available This paper analyses the relationship between dissociative experiences and road traffic incidents (crashes and traffic tickets in drivers (n=295 from Mar del Plata (Argentina city. A self-report questionnaire was applied to assess traffic crash involvement and sociodemographic variables. Dissociative tendencies were assessed by a modified version of the DES scale. To examine differences in DES scores tests of the difference of means were applied. Drivers who reported to be previously involved in traffic incidents obtained higher puntuations in the dissociative experiences scale than drivers who did not report such events. This result is observed for the total scale and for the three sub-scales (absorption, amnesia and depersonalization. However, differences appeared mainly for minor damage collisions. Further studies are needed to evaluate the role of dissociative tendencies as a risk factor in road traffic safety.

  7. The treatment of iodine and chlorine chemistry in the risk assessment of deep radioactive waste disposal

    International Nuclear Information System (INIS)

    Jones, Michael A.

    1992-01-01

    The predicted contribution from 129 I, 131 I and 36 Cl to the radiological risk from a radioactive waste repository may be enhanced by the assumption of limited retardation in the near field and geosphere. However, migration of these radionuclides may be affected by their chemical speciation and retarded by a range of sorption processes. The chemical behaviour of iodine and chlorine is determined emphasizing i) aqueous speciations, ii) sorption onto inorganic substrates, and iii) the role of organic matter and microbes. Recommendations to enhance the methodology include i) consideration of aqueous speciation of iodine, both metal and organic complexes, ii) mechanistic simulation of iodine sorption by ion exchange and electrostatic/covalent adsorption, iii) simulation of enzymatically enhanced sorption of iodine and chlorine onto organic substrates, iv) enhancement of HMIP K d databases to include iodine and chlorine data for the geosphere and biosphere. A well defined programme of additional data collection, modelling studies and experimental investigations is recommended to achieve these enhancements. (author)

  8. Development of silver impregnated alumina for iodine separation from off-gas streams

    Energy Technology Data Exchange (ETDEWEB)

    Funabashi, Kiyomi; Fukasawa, Tetsuo; Kikuchi, Makoto [Energy Research Laboratory, Hitachi (Japan)] [and others

    1995-02-01

    An inorganic iodine adsorbent, silver impregnated alumina (AgA), has been developed to separate iodine effectively from off-gas streams of nuclear facilities and to decrease the volume of waste (spent adsorbent). Iodine removal efficiency was improved at relatively high humidity by using alumina carrier with two different pore diameters. Waste volume reduction was achieved by impregnating relatively large amounts of silver into the alumina pores. The developed adsorbent was tested first with simulated off-gas streams under various experimental conditions and finally with actual off-gas streams of the Karlsruhe reprocessing plant. The decontamination factor (DF) was about 100 with the AgA bed depth of 2cm at 70% relative humidity, which was a DF one order higher than that when AgA with one pore size was used. Iodine adsorption capacity was checked by passing excess iodine into the AgA bed. Values were about 0.12 and 0.35 g-I/cm`-AgA bed for 10 and 24wt% silver impregnated AgA, respectively. The results obtained in this study demonstrated the applicability of the developed AgA to the off-gas treatment system of nuclear facilities.

  9. Adsorption behavior of sulfur-containing amino acid molecule on transition metal surface studied by S K-edge NEXAFS

    International Nuclear Information System (INIS)

    Yagi, S.; Matsumura, K.; Nakano, Y.; Ikenaga, E.; Sardar, S.A.; Syed, J.A.; Soda, K.; Hashimoto, E.; Tanaka, K.; Taniguchi, M.

    2003-01-01

    Adsorption behavior of a sulfur-containing amino acid L-cysteine molecule on transition metal surface have been investigated by S K-edge near-edge X-ray absorption fine structure. The L-cysteine molecule for first adsorption layer was found to dissociate on polycrystalline nickel surface, whereas molecularly adsorbed on copper surface at room temperature. Most of the L-cysteine molecules have been dissociated on nickel surface in annealing condition up to 353 K. On the other hand, the L-cysteine molecule did not dissociate on copper surface and the elongation of the S-C bonding occurred at 353 K

  10. Atrioventricular Dissociation after Electroconvulsive Therapy

    Directory of Open Access Journals (Sweden)

    Siegfried William Yu

    2011-01-01

    Full Text Available Electroconvulsive therapy (ECT is increasingly used as a treatment for psychiatric disorders. Cardiac effects are the principal cause of medical complications in these patients. We report a case of atrioventricular (AV dissociation that occurred after ECT that was treated with pacemaker implantation. The mechanisms contributing to the onset of AV dissociation in this patient, and the management and rationale for device therapy, in light of the most recent guidelines, are reviewed.

  11. Doping characteristics of iodine on as-grown chemical vapor deposited graphene on Pt

    Energy Technology Data Exchange (ETDEWEB)

    Kim, HoKwon, E-mail: hknano@gmail.com [Université Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, 17 rue des Martyrs, F-38054 Grenoble (France); Renault, Olivier [Université Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, 17 rue des Martyrs, F-38054 Grenoble (France); Tyurnina, Anastasia; Guillet, Jean-François; Simonato, Jean-Pierre [Université Grenoble Alpes, F-38000 Grenoble (France); CEA, LITEN/DTMN, F-38054 Grenoble (France); Rouchon, Denis; Mariolle, Denis; Chevalier, Nicolas [Université Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, 17 rue des Martyrs, F-38054 Grenoble (France); Dijon, Jean [Université Grenoble Alpes, F-38000 Grenoble (France); CEA, LITEN/DTMN, F-38054 Grenoble (France)

    2015-12-15

    Using laboratory X-ray photoelectron emission microscopy (XPEEM), we investigated the doping efficiency and thermal stability of iodine on as-grown graphene on Pt. After iodine adsorption of graphene in saturated vapor of I{sub 2,} monolayer and bilayer graphene exhibited work function of 4.93 eV and 4.87 eV, respectively. Annealing of the doped monolayer graphene at 100 °C led to desorption of hydrocarbons, which increased the work function of monolayer graphene by ~0.2 eV. The composition of the polyiodide complexes evolved upon a step-by-step annealing at temperatures from 100 °C to 300 °C while the work-function non-monotonically changed with decreasing iodine content. The iodine dopant was stable at relatively high temperature as a significant amount of iodine remained up to the annealing temperature of 350 °C. - Highlights: • Laboratory XPEEM demonstrates that iodine can effectively p-dope as-grown graphene on Pt with a work-function value up to 5.1 eV. • On the other hand, residual hydrocarbon contamination decreases the work function by up to ~0.2 eV. • The spontaneous intercalation of as-grown few-layered graphene is not easily feasible. • The iodine dopant was not completely removed up to the annealing temperature of 350 °C. • The I{sub 3}{sup −} and I{sub 5}{sup −} polyiodide content ratio of I-doped Gr/Pt decreases with annealing temperature.

  12. Dissociative disorders in DSM-5.

    Science.gov (United States)

    Spiegel, David; Lewis-Fernández, Roberto; Lanius, Ruth; Vermetten, Eric; Simeon, Daphne; Friedman, Matthew

    2013-01-01

    The rationale, research literature, and proposed changes to the dissociative disorders and conversion disorder in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) are presented. Dissociative identity disorder will include reference to possession as well as identity fragmentation, to make the disorder more applicable to culturally diverse situations. Dissociative amnesia will include dissociative fugue as a subtype, since fugue is a rare disorder that always involves amnesia but does not always include confused wandering or loss of personality identity. Depersonalization disorder will include derealization as well, since the two often co-occur. A dissociative subtype of posttraumatic stress disorder (PTSD), defined by the presence of depersonalization or derealization in addition to other PTSD symptoms, is being recommended, based upon new epidemiological and neuroimaging evidence linking it to an early life history of adversity and a combination of frontal activation and limbic inhibition. Conversion disorder (functional neurological symptom disorder) will likely remain with the somatic symptom disorders, despite considerable dissociative comorbidity.

  13. A Spectroscopic Method for Determining Free Iodine in Iodinated Fatty-Acid Esters

    Science.gov (United States)

    Klyubin, V. V.; Klyubina, K. A.; Makovetskaya, K. N.

    2018-01-01

    It is shown that the concentration of free iodine in samples of iodinated fatty-acid esters can be measured using the electronic absorption spectra of their solutions in ethanol. The method proposed is rather simple in use and highly sensitive, allowing detection of presence of less than 10 ppm of free iodine in iodinated compounds. It is shown using the example of Lipiodol that this makes it possible to easily detect small amounts of free iodine in samples containing bound iodine in concentrations down to 40 wt %.

  14. Separation of iodine-131 from water using isotopic exchange with iodine-starch compound

    International Nuclear Information System (INIS)

    Ignatov, V.P.; Kolomejtseva, I.V.

    1990-01-01

    Conditions of iodine isotopic exchange with iodine-starch compound (ISC) were studied with the aim of compound utilizatoin for radioactive iodine separation from solution. It is shown that in pH range from 2 to 7 the degree of iodine extraction and coefficient of its distribution practically do not depend on pH, at pH>7 ISC destruction (decolorizing) starts and iodine extraction decreases. Rapid method of iodine separation from solution is suggested. The method can be used in radiochemical techniques. The degree of extraction equals 80 %, a higher degree of extraction can not be achieved owing to ISC formation peculiarities

  15. Water Adsorption on TiO2

    DEFF Research Database (Denmark)

    Hammer, Bjørk; Wendt, Stefan; Besenbacher, Flemming

    2010-01-01

    Scanning Tunneling Microscopy (STM) studies and Density Functional Theory (DFT) investigations of the interaction of water with the rutile TiO2 (110) surface are summarized. From high-resolution STM the following reactions have been revealed: water adsorption and diffusion in the Ti troughs, water...... dissociation in bridging oxygen vacancies, assembly of adsorbed water monomers into rapidly diffusing water dimers, and formation of water dimers by reduction of oxygen molecules. The STM results are rationalized based on DFT calculations, revealing the bonding geometries and reaction pathways of the water...

  16. Radioactive iodine absorbing properties of tetrathiafulvalene

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Tomiyasu; Nakamura, Asao (Ajinomoto Co. Inc., Kawasaki, Kanagawa (Japan). Central Research Labs.); Nogawa, Norio; Oohashi, Kunio; Morikawa, Naotake

    1989-05-01

    For the purpose of searching some effective absorbents of gaseous radioactive iodine, 16 substances considered as having an affinity for iodine were investigated with regular iodine and /sup 125/I. In a preliminary survey, only tetrathiafulvalene (TTF) was found to have satisfactory absorbing properties comparable to activated charcoal. A further detailed comparison of the properties between TTF and activated charcoal led us to the conclusion that the former has more preferable properties as absorbent of radioactive iodine than the latter in all points studied. The results are summarized as follows: (1) The absorption of iodine on TTF in atmosphere was about twice as much as that on activated charcoal. Desorption of iodine from saturatedly absorbed iodine on TTF was practically negligible except trace amount of initial desorption, while that on activated charcoal was considerable (3%/50h) even in the air at room temperature. (2) Absorbed amount of iodine on activated charcoal decreased with increasing gaseous iodine concentration, air flow rate, on humidity of flowing-air. On the other hand, those factors scarcely affected that on TTF. Under an air flow rate of 1m/s, activated charcoal absorbs only 80% of iodine, while TTF absorbs more than 99%. (3) In flowing-air saturated with water vapor, iodine absorbed on activated charcoal was gradually liberated although by small amount (0.08%/100h), while that on TTF was much more stable for a long period (0.004%/100h). As a conclusion, TTF is considered to be useful as a quite effective radioactive iodine absorbent, especially in the case where protection from radioactive iodine should be serious, though it is expensive now. (author).

  17. Radioactive iodine absorbing properties of tetrathiafulvalene

    International Nuclear Information System (INIS)

    Ito, Tomiyasu; Nakamura, Asao; Nogawa, Norio; Oohashi, Kunio; Morikawa, Naotake.

    1989-01-01

    For the purpose of searching some effective absorbents of gaseous radioactive iodine, 16 substances considered as having an affinity for iodine were investigated with regular iodine and 125 I. In a preliminary survey, only tetrathiafulvalene (TTF) was found to have satisfactory absorbing properties comparable to activated charcoal. A further detailed comparison of the properties between TTF and activated charcoal led us to the conclusion that the former has more preferable properties as absorbent of radioactive iodine than the latter in all points studied. The results are summarized as follows: (1) The absorption of iodine on TTF in atmosphere was about twice as much as that on activated charcoal. Desorption of iodine from saturatedly absorbed iodine on TTF was practically negligible except trace amount of initial desorption, while that on activated charcoal was considerable (3%/50h) even in the air at room temperature. (2) Absorbed amount of iodine on activated charcoal decreased with increasing gaseous iodine concentration, air flow rate, on humidity of flowing-air. On the other hand, those factors scarcely affected that on TTF. Under an air flow rate of 1m/s, activated charcoal absorbs only 80% of iodine, while TTF absorbs more than 99%. (3) In flowing-air saturated with water vapor, iodine absorbed on activated charcoal was gradually liberated although by small amount (0.08%/100h), while that on TTF was much more stable for a long period (0.004%/100h). As a conclusion, TTF is considered to be useful as a quite effective radioactive iodine absorbent, especially in the case where protection from radioactive iodine should be serious, though it is expensive now. (author)

  18. Geochemical Cycling of Iodine Species in Soils

    International Nuclear Information System (INIS)

    Hu, Q.; Moran, J.E.; Blackwood, V.

    2007-01-01

    Iodine is an important element in studies of environmental protection and human health, global-scale hydrologic processes and nuclear nonproliferation. Biogeochemical cycling of iodine in soils is complex, because iodine occurs in multiple oxidation states and as inorganic and organic species that may be hydrophilic, atmophilic, and biophilic. In this study, we applied new analytical techniques to study the content and speciation of stable iodine in representative surface soils, and sorption and transport behavior of iodine species (iodide, iodate, and 4-iodoaniline) in sediments collected at numerous nuclear facilities in the United States, where anthropogenic 129 I from prior nuclear fuel processing activities poses an environmental risk. The surface soil samples were chosen for their geographic locations (e.g., near the ocean or nuclear facilities) and for their differing physico-chemical characteristics (organic matter, texture, etc). Extracted solutions were analyzed by IC and ICP-MS methods to determine iodine concentrations and to examine iodine speciation (iodide, iodate, and organic iodine). In natural soils, iodine is mostly (nearly 90% of total iodine) present as organic species, while inorganic iodine becomes important (up to 50%) only in sediments with low organic matter. Results from laboratory column studies, aimed at examining transport of different iodine species, showed much greater retardation of 4-iodoaniline than iodide or iodate. Careful attention must be given to potential interconversion among species when interpreting the biogeochemical behavior of iodine in the environment. In addition to speciation, input concentration and residence time effects will influence the biogeochemical cycling of anthropogenic 129I deposited on surface soils

  19. Recovery of iodine as iodine-125 from biological materials prior to assay

    International Nuclear Information System (INIS)

    Jones, G.B.; Belling, G.B.; Buckley, R.A.

    1979-01-01

    In biological tissues iodine is usually present as iodoamino acids or iodoproteins. The organic material must be oxidised and the iodine converted into iodate prior to the final spectrophotometric determination. At parts per billion (10 9 ) levels, recoveries of added iodine are difficult to measure precisely as iodine can easily be lost from the sample and added inorganic iodine may not be recovered in the same proportions as the naturally occurring iodine. Iodine-125 provides a much more sensitive, specific and accurate means of testing the recovery of nanogram amounts of iodine from biological tissues and it can be incorporated into tissues in the naturally occurring compounds. Plants can be grown in a solution culture containing iodine-125 and animals can be injected with iodine-125 to provide tissues where naturally occurring iodine compounds are labelled with radioactive iodine. These tissues can be used to examine the recovery of iodine after oven drying, freeze drying, alkali ashing and acid digestion of the samples. Experimental details are given for spinach, tobacco, oats, cauliflower and thyroid. Results are given and discussed. (author)

  20. Oxidation of iodide and iodine on birnessite (delta-MnO2) in the pH range 4-8.

    Science.gov (United States)

    Allard, Sébastien; von Gunten, Urs; Sahli, Elisabeth; Nicolau, Rudy; Gallard, Hervé

    2009-08-01

    The oxidation of iodide by synthetic birnessite (delta-MnO(2)) was studied in perchlorate media in the pH range 4-8. Iodine (I(2)) was detected as an oxidation product that was subsequently further oxidized to iodate (IO(3)(-)). The third order rate constants, second order on iodide and first order on manganese oxide, determined by extraction of iodine in benzene decreased with increasing pH (6.3-7.5) from 1790 to 3.1M(-2) s(-1). Both iodine and iodate were found to adsorb significantly on birnessite with an adsorption capacity of 12.7 microM/g for iodate at pH 5.7. The rate of iodine oxidation by birnessite decreased with increasing ionic strength, which resulted in a lower rate of iodate formation. The production of iodine in iodide-containing waters in contact with manganese oxides may result in the formation of undesired iodinated organic compounds (taste and odor, toxicity) in natural and technical systems. The probability of the formation of such compounds is highest in the pH range 5-7.5. For pH iodine is quickly oxidized to iodate, a non-toxic and stable sink for iodine. At pH >7.5, iodide is not oxidized to a significant extent.

  1. Delayed development, death and abnormal thyroglobulin in rats maintained on low-iodine diets

    International Nuclear Information System (INIS)

    Van Middlesworth, L.

    1976-01-01

    Rats weaned on Remington Low Iodine Diet (0.006 to 0.009 μgI/g) grew poorly, were very slow to breed, and 83% of their pups died in the neonatal period. A large iodide supplement (100μgI/d) improved growth of the females to almost normal but did not improve growth of males. With the iodide supplement they bred at an earlier age than rats fed the low iodide Remington diet but still 73% of the pups died before weaning. The addition of a vitamin mixture (biotin, vitamin B 12 , E, patothenic acid, riboflavin, thiamine and pyridoxine) to Remington Diet resulted in delayed pregnancies but 86% survival of offspring. A more nutritious low-iodine diet with a 'complete' mineral and vitamin supplement improved growth and survival, and the litters were delivered at the normal time. However, this more complete diet contained more iodine than the Remington diet. During the neonatal period, all the low iodine diets resulted in offspring that were unable to make T 3 as readily as adults fed the same diet. Pups from dams fed the Remington diet had thyroblobulin with lower sedimentation constants (18S and 12S) than was found in normal newborns. This unfolded and dissociated thyroglobulin may be an inadequate source of thyroid hormones, but it may hydrolyse more rapidly than normal 19S thyroglobulin. It is concluded that rats raised on a diet severely deficient in iodine were unable to litter until they were older than normal rats, and the survival of the offspring was poor unless the diet was supplemented with a vitamin mixture. The synthesis of thyroid hormones in low iodine neonatal rats was more severely impaired than in adults. (author)

  2. Nighttime atmospheric chemistry of iodine

    Science.gov (United States)

    Saiz-Lopez, Alfonso; Plane, John M. C.; Cuevas, Carlos A.; Mahajan, Anoop S.; Lamarque, Jean-François; Kinnison, Douglas E.

    2016-12-01

    Little attention has so far been paid to the nighttime atmospheric chemistry of iodine species. Current atmospheric models predict a buildup of HOI and I2 during the night that leads to a spike of IO at sunrise, which is not observed by measurements. In this work, electronic structure calculations are used to survey possible reactions that HOI and I2 could undergo at night in the lower troposphere, and hence reduce their nighttime accumulation. The new reaction NO3+ HOI → IO + HNO3 is proposed, with a rate coefficient calculated from statistical rate theory over the temperature range 260-300 K and at a pressure of 1000 hPa to be k(T) = 2.7 × 10-12 (300 K/T)2.66 cm3 molecule-1 s-1. This reaction is included in two atmospheric models, along with the known reaction between I2 and NO3, to explore a new nocturnal iodine radical activation mechanism. The results show that this iodine scheme leads to a considerable reduction of nighttime HOI and I2, which results in the enhancement of more than 25 % of nighttime ocean emissions of HOI + I2 and the removal of the anomalous spike of IO at sunrise. We suggest that active nighttime iodine can also have a considerable, so far unrecognized, impact on the reduction of the NO3 radical levels in the marine boundary layer (MBL) and hence upon the nocturnal oxidizing capacity of the marine atmosphere. The effect of this is exemplified by the indirect effect on dimethyl sulfide (DMS) oxidation.

  3. New iodine filter pack design

    International Nuclear Information System (INIS)

    Blackbee, B.A.

    1977-10-01

    To enable Naval Emergency Monitoring Teams to fulfil their role in the field it was necessary to locate or design a replacement filter pack for the collection of radioactive iodine air samples. Collaboration with the Berkeley Laboratories of the Central Electricity Generating Board provided the necessary starting point for a suitable type of package. Further development by NGTE (West Drayton) yielded the improved filter pack which is the subject of this memorandum. (author)

  4. Adsorption Model for Off-Gas Separation

    Energy Technology Data Exchange (ETDEWEB)

    Veronica J. Rutledge

    2011-03-01

    The absence of industrial scale nuclear fuel reprocessing in the U.S. has precluded the necessary driver for developing the advanced simulation capability now prevalent in so many other countries. Thus, it is essential to model complex series of unit operations to simulate, understand, and predict inherent transient behavior and feedback loops. A capability of accurately simulating the dynamic behavior of advanced fuel cycle separation processes will provide substantial cost savings and many technical benefits. The specific fuel cycle separation process discussed in this report is the off-gas treatment system. The off-gas separation consists of a series of scrubbers and adsorption beds to capture constituents of interest. Dynamic models are being developed to simulate each unit operation involved so each unit operation can be used as a stand-alone model and in series with multiple others. Currently, an adsorption model has been developed in gPROMS software. Inputs include gas stream constituents, sorbent, and column properties, equilibrium and kinetic data, and inlet conditions. It models dispersed plug flow in a packed bed under non-isothermal and non-isobaric conditions for a multiple component gas stream. The simulation outputs component concentrations along the column length as a function of time from which the breakthrough data is obtained. It also outputs temperature along the column length as a function of time and pressure drop along the column length. Experimental data will be input into the adsorption model to develop a model specific for iodine adsorption on silver mordenite as well as model(s) specific for krypton and xenon adsorption. The model will be validated with experimental breakthrough curves. Another future off-gas modeling goal is to develop a model for the unit operation absorption. The off-gas models will be made available via the server or web for evaluation by customers.

  5. Iodine frequency references for space

    International Nuclear Information System (INIS)

    Schuldt, Thilo; Braxmaier, Claus; Döringshoff, Klaus; Peters, Achim; Oswald, Markus; Johann, Ulrich

    2017-01-01

    Optical frequency references are a key element for the realization of future space missions. They are needed for missions related to tests of fundamental physics, gravitational wave detection, Earth observation and navigation and ranging. In missions such as GRACE follow-on or LISA the optical frequency reference is used as light source for high-sensitivity inter-satellite distance metrology. While cavity-based systems are current baseline e.g. for LISA, frequency stabilization on a hyperfine transition in molecular iodine near 532 nm is a promising alternative. Due to its absolute frequency, iodine standards crucially simplify the initial spacecraft acquisition procedures. Current setups fulfill the GRACE-FO and LISA frequency stability requirements and are realized near Engineering Model level. We present the current status of our developments on Elegant Breadboard (EBB) and Engineering Model (EM) level taking into account specific design criteria for space compatibility such as compactness (size iodine spectroscopy EM: 38 × 18 × 10 cm 3 ) and robustness. Both setups achieved similar frequency stabilities of ∼ 1 · 10 −14 at an integration time of 1 s and below 5 · 10 −15 at integration times between 10 s and 1000 s. Furthermore, we present an even more compact design currently developed for a sounding rocket mission with launch in 2017. (paper)

  6. Iodine Absorption Cells Purity Testing

    Directory of Open Access Journals (Sweden)

    Jan Hrabina

    2017-01-01

    Full Text Available This article deals with the evaluation of the chemical purity of iodine-filled absorption cells and the optical frequency references used for the frequency locking of laser standards. We summarize the recent trends and progress in absorption cell technology and we focus on methods for iodine cell purity testing. We compare two independent experimental systems based on the laser-induced fluorescence method, showing an improvement of measurement uncertainty by introducing a compensation system reducing unwanted influences. We show the advantages of this technique, which is relatively simple and does not require extensive hardware equipment. As an alternative to the traditionally used methods we propose an approach of hyperfine transitions’ spectral linewidth measurement. The key characteristic of this method is demonstrated on a set of testing iodine cells. The relationship between laser-induced fluorescence and transition linewidth methods will be presented as well as a summary of the advantages and disadvantages of the proposed technique (in comparison with traditional measurement approaches.

  7. Iodine chemistry in a reactor regulation

    International Nuclear Information System (INIS)

    Powers, D.A.

    1996-01-01

    Radioactive iodine has always been an important consideration in the regulation of nuclear power reactors to assure the health and safety of the public. Regulators adopted conservatively bounding predictions of iodine behavior in the earliest days of the development of nuclear power because there was so little known about either accidents or the chemistry of iodine. Today there is a flood of new information and understanding of the chemistry of iodine under reactor accident conditions. This paper offers some thoughts on how the community of scientists engaged in the study of iodine chemistry can present the results of their work so that it is more immediately adopted by the regulator. It is suggested that the scientific community consider the concept of consensus standards so effectively used within the engineering community to define the status of the study of radioactive iodine chemistry for reactor safety. (author) 9 refs

  8. Iodine chemistry in a reactor regulation

    Energy Technology Data Exchange (ETDEWEB)

    Powers, D A [Nuclear Regulatory Commission, Washington, DC (United States). Advisory Committee on Reactor Safeguards

    1996-12-01

    Radioactive iodine has always been an important consideration in the regulation of nuclear power reactors to assure the health and safety of the public. Regulators adopted conservatively bounding predictions of iodine behavior in the earliest days of the development of nuclear power because there was so little known about either accidents or the chemistry of iodine. Today there is a flood of new information and understanding of the chemistry of iodine under reactor accident conditions. This paper offers some thoughts on how the community of scientists engaged in the study of iodine chemistry can present the results of their work so that it is more immediately adopted by the regulator. It is suggested that the scientific community consider the concept of consensus standards so effectively used within the engineering community to define the status of the study of radioactive iodine chemistry for reactor safety. (author) 9 refs.

  9. Application of radiopharmaceuticals in iodine disorder studies

    International Nuclear Information System (INIS)

    Rajurkar, N.S.

    2015-01-01

    Iodine is an essential trace element and is of much interest in nutritional research. It is essential for the production of the hormones in the thyroid gland. However, deficiency or excess of iodine can cause disorders, commonly known as iodine disorders. Total quantity of iodine present in the body is 15-20 mg, mostly in thyroid gland and the safe and adequate intake of iodine is in the range of 50-200 μg.d -1 . Most of the iodine taken from food is accumulated in thyroid glands which plays a vital role in the well being as it controls growth and metabolism. In some people gland becomes over active (hyper thyroiditis) and in some people gland becomes sluggish (hypo thyroiditis). However, both the conditions are unhealthy and lead to serious consequences. The condition can be detected and treated with the help of radioiodine

  10. Criteria for safe working with iodine-125

    International Nuclear Information System (INIS)

    Linsley, G.S.

    1977-01-01

    Radio-immunoassay and other saturation assay tests involving the use of iodine-125 are finding wide application for the determination of hormone concentrations in biological fluids. In such tests, iodinations involving concentrations of a milli-curie per micro-litre are common. Iodine-125 presents a problem from the monitoring standpoint because of its low energy photon emission (27 and 35 keV). Iodine is preferentially taken up by the thyroid gland and work involving moderate amounts of radio-iodine may give rise to a significant hazard in an accident situation. The general precautions which should be taken in work with unsealed radioactive substances are briefly summarized, working limits for iodine-125 are identified, and methods of personal protection and monitoring in an emergency situation described. (author)

  11. Local radiolytic effectiveness of Auger electrons of iodine-125 in benzene-iodine solutions

    International Nuclear Information System (INIS)

    Uenak, P.; Uenak, T.

    1987-01-01

    High radiotoxicity of iodine-125 has been mainly attributed to the local radiolytic effects of Auger electrons on biological systems. In the present study, experimental and theoretical results are compared. The agreement between the experimental and theoretical results explains that the energy absorption of iodine aggregates has an important role in the radiolytic effectiveness of Auger electrons and iodine-125 in benzene-iodine solutions. (author) 18 refs.; 3 figs

  12. Measurement of thyroid volume, iodine concentration and total iodine content by CT and its clinical significance

    International Nuclear Information System (INIS)

    Nakaji, Shunsuke; Imanishi, Yoshimasa; Okamoto, Kyouko; Shinagawa, Toshihito

    2007-01-01

    Recently, Imanishi et al have developed new CT software for quantitative in vivo measurement of thyroid iodine. Using a CT system with the software, we measured volume, iodine concentration and total iodine content of thyroids in 63 controls and 435 patients with various diffuse thyroid diseases and thyroid nodules. In controls, all of them showed no difference between the sexes. Although the iodine concentration of the thyroid showed no difference among children, adults and seniles, the volume and total iodine content of the thyroid appeared smaller in children and seniles than in adults. In addition, although the volume and iodine concentration of the thyroid had two peaks in distribution, the total iodine content had almost normal distribution. Normal range of volume, iodine concentration and total iodine content in adults were 5.2-15.5 cm 3 , 0.28831-0.85919 mg/cm 3 and 2.35-11.69 mg, respectively. In thyroid nodule, there is no significant difference in volume, iodine concentration and total iodine content between benign and malignant nodules. All nodules with iodine concentration of less than 0.00007 mg/cm 3 were benign. No thyroid was higher in iodine concentration than the normal range although the thyroid was lower in 78.7% of patients with diffuse thyroid diseases. In all thyroids with increasing iodine concentration and total iodine content in medication course, thyroidal symptoms and signs were uncontrollable by the medication. In 43.8% of patients with long-period systemic diseases, the thyroid showed abnormality in any of the three. We concluded that quantitative in vivo measurement of thyroid iodine by CT could assist the diagnosis of thyroid diseases and decision of therapeutic methods. (author)

  13. Equine goiter associated with excess dietary iodine.

    Science.gov (United States)

    Eroksuz, H; Eroksuz, Y; Ozer, H; Ceribasi, A O; Yaman, I; Ilhan, N

    2004-06-01

    Naturally occurring goiter cases are described in 2 newborn Arabian foals whose mares were supplemented with excess iodine during the final 24 w of the pregnancy. Six nursing foals and 2 mares were also affected clinically with thyroid hypertrophy. At least 12 times the maximum tolerable level of iodine supplementation was given, as the daily iodine intake for each mare was 299 mg. The prevalence of goiter cases was 2 and 9% in the mares and foals, respectively.

  14. Salivary gland dysfunction following radioactive iodine therapy

    International Nuclear Information System (INIS)

    Wiesenfeld, D.; Webster, G.; Cameron, F.; Ferguson, M.M.; MacFadyen, E.E.; MacFarlane, T.W.

    1983-01-01

    Radioactive iodine is used extensively for the treatment of thyrotoxicosis and thyroid carcinoma. Iodine is actively taken up by the salivary glands and, following its use, salivary dysfunction may result as a consequence of radiation damage. The literature is reviewed and a case is reported in which a patient presented with a significant increase in caries rate attributed to salivary dysfunction following radioactive iodine therapy for a thyroid carcinoma

  15. High coverage hydrogen adsorption on the Fe{sub 3}O{sub 4}(1 1 0) surface

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Xiaohu, E-mail: yuxiaohu950203@126.com [College of Physics and Electrical Engineering, Anyang Normal University, Anyang, Henan 455000 (China); State Key laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, Shanxi 030001 (China); Zhang, Xuemei [College of Physics and Electrical Engineering, Anyang Normal University, Anyang, Henan 455000 (China); Wang, Shengguang [State Key laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, Shanxi 030001 (China); Synfuels China Co., Ltd., Huairou, Beijing 101407 (China)

    2015-10-30

    Graphical abstract: - Highlights: • Hydrogen adsorption on the A and B termination layers of the Fe{sub 3}O{sub 4}(1 1 0) surface at different coverage has been studied by DFT + U method. • The adsorption of hydrogen prefers surface oxygen atoms on both Fe{sub 3}O{sub 4}(1 1 0) surface layers. • The more stable A layer has stronger adsorption energy than the less stable B layer. • The saturation coverage has two dissociatively adsorbed H{sub 2} on the A layer, and one dissociatively adsorbed H{sub 2} on the B layer. - Abstract: Hydrogen adsorption on the A and B termination layers of the Fe{sub 3}O{sub 4}(1 1 0) surface at different coverage has been systematically studied by density functional theory calculations including an on-site Hubbard term (GGA + U). The adsorption of hydrogen prefers surface oxygen atoms on both layers. The more stable A layer has stronger adsorption energy than the less stable B layer. The saturation coverage has two dissociatively adsorbed H{sub 2} on the A layer, and one dissociatively adsorbed H{sub 2} on the B layer. The adsorption mechanism has been analyzed on the basis of projected density of states (PDOS).

  16. Estimation of iodine intake from various urinary iodine measurements in population studies

    DEFF Research Database (Denmark)

    Vejbjerg, P.; Knudsen, N.; Perrild, H.

    2009-01-01

    Background: Iodine intake is often measured by a surrogate measure, namely urine iodine excretion as almost all ingested iodine is excreted in the urine. However, the methods for urine collection and the reporting of the results vary. These methods, and their advantages and disadvantages, are con...

  17. Molecular environment of iodine in naturally iodinated humic substances: Insight from X-ray absorption spectroscopy

    International Nuclear Information System (INIS)

    Schlegel, Michel L.; Mercier-Bion, Florence; Barre, Nicole; Reiller, Pascal; Moulin, Valerie

    2006-01-01

    The molecular environment of iodine in reference inorganic and organic compounds, and in dry humic and fulvic acids (HAs and FAs) extracted from subsurface and deep aquifers was probed by iodine L-3-edge X-ray absorption spectroscopy. The X-ray absorption near-edge structure (XANES) of iodine spectra from HAs and FAs resembled those of organic references and displayed structural features consistent with iodine forming covalent bonds with organic molecules. Simulation of XANES spectra by linear combination of reference spectra suggested the predominance of iodine forming covalent bonds to aromatic rings (aromatic-bound iodine). Comparison of extended X-ray absorption fine structure (EXAFS) spectra of reference and samples further showed that iodine was surrounded by carbon shells at distances comparable to those for references containing aromatic-bound iodine. Quantitative analysis of EXAFS spectra indicated that iodine was bound to about one carbon at a distance d(I-C) of 2.01(4)-2.04(9) angstrom, which was comparable to the distances observed for aromatic-bound iodine in references (1.99(1)-2.07(6) angstrom), and significantly shorter than that observed for aliphatic-bound iodine (2.15(2)-2.16(2) angstrom). These results are in agreement with previous conclusions from X-ray photoelectron spectroscopy and from electro-spray ionization mass spectrometry. These results collectively suggest that the aromatic-bound iodine is stable in the various aquifers of this study. (authors)

  18. 127I Moessbauer study of some oxygen bonded iodine(I) and iodine(III) complexes

    International Nuclear Information System (INIS)

    Bardhan, M.; Birchall, T.; Frampton, C.; Kapoor, P.

    1988-01-01

    127 I Moessbauer spectra have been recorded at 4.2 0 K for a series of oxygen bonded iodine(I) and iodine(III) complexes. The sign of the quadrupole coupling constant is dependant only on the primary arrangement of ligands about the central iodine nucleus whereas the magnitude and the asymmetry parameter are more sensitive to ligand electronegativity and type. (orig.)

  19. Iodine deficiency in pregnancy and the effects of maternal iodine supplementation on the offspring: a review

    NARCIS (Netherlands)

    Zimmermann, M.B.

    2009-01-01

    The World Health Organization (WHO) recently increased their recommended iodine intake during pregnancy from 200 to 250 µg/d and suggested that a median urinary iodine (UI) concentration of 150-249 µg/L indicates adequate iodine intake in pregnant women. Thyrotropin concentrations in blood collected

  20. Iodine requirements and the risks and benefits of correcting iodine deficiency in populations

    NARCIS (Netherlands)

    Zimmermann, M.B.

    2008-01-01

    Iodine deficiency has multiple adverse effects on growth and development due to inadequate thyroid hormone production that are termed the iodine deficiency disorders (IDD). IDD remains the most common cause of preventable mental impairment worldwide. IDD assessment methods include urinary iodine

  1. Absorption spectrum of Iodine around 5915 A

    International Nuclear Information System (INIS)

    1990-01-01

    The iodine absorption spectrum around 5915 A is of interest for many authors especially the hyperfine structure of the iodine line. Lodine absorption spectrum was obtained due to the interaction of iodine vapour with dye laser [(R6G) (0.5A) scanning range around 5915 A] which is pumped by(Ar + )laser absorption spectrum. The decrease in the peak of the transmission line around 5915 A shows the signal futher decreased by heating the iodine cell. This analysis has been done using a monochromator

  2. Hygienic assessment of radioactive iodine isotopes

    International Nuclear Information System (INIS)

    Vasilenko, I.Ya.

    1987-01-01

    Sources of radioactive iodine isotopes and their biological significance depending on the way of intake are discussed. The degree of food contamination by radioactive iodine as well as products, which serve as the source of its intake into the human body, and results of their processing are considered. The danger of radioactive iodine intake by different groups of population as well as thyroid irradiation effects are discussed. Description of activities, directed to the human body protection against radioactive iodine and assessment of these protection measures efficiency is presented

  3. Iodine-129 in thyroids of grazing animals

    International Nuclear Information System (INIS)

    Ballad, R.V.; Holman, D.W.; Hennecke, E.W.; Johnson, J.E.; Manuel, O.K.; Nicholson, L.M.

    1976-01-01

    A combination of neutron activation and mass spectrometry has been used to determine the concentrations of fissiogenic 129 I and stable 127 I in thyroids of grazing animals and in mineral iodine. The 129 I/ 127 I ratios are lowest in mineral iodine and in a given area lower in cow thyroids than in deer thyroids. Near saturation levels of mineral iodine in commercial feeds and salt licks may account for differences in the 129 I levels of cows and deer. Values of the 129 I/ 127 I ratio in deer appear to vary inversely with the iodine concentration of the thyroid. (author)

  4. Photochemistry of DNA containing iodinated cytosine

    Energy Technology Data Exchange (ETDEWEB)

    Rahn, R O; Stafford, R S [Oak Ridge National Lab., TN (USA)

    1979-10-01

    Irradiation at 313 nm of compounds containing iodinated cytosine moieties results in the photolysis of iodine. Photolysis occurs with a quantum yield of 0.022-0.024 for 5-iododeoxycytidine and 5-iododeoxycytidine monophosphate, and 0.004-0.008 for iodinated DNA as well as for iodinated polycytidylate. Photodegradation of the cytosine moiety occurs when air is present during irradiation, presumably due to the reaction of oxygen with the cytosyl radical formed when iodine is lost. This oxygen promoted photodegradation destroys the cytosine chromophore and is complete in the monomers but occurs to only a limited extent in the polymers. In the absence of oxygen or in the presence of ethanol, photodegradation is prevented and the loss of iodine leads exclusively to the formation of the cytosine chromophore. In DNA, the loss of iodine is accompanied by the formation of sugar damage and/or chain breaks. As measured by sedimentation in alkaline sucrose gradients, approximately one break is made for every six iodines lost in denatured DNA. The frequency of chain breakage per iodine photolyzed is reduced 2-fold in renatured DNA. Analysis in neutral gradients suggests that half of the breaks observed in alkali are alkali-labile bonds. Both ethanol and cysteamine reduce the number of chain breaks in alkali by approximately 3-fold.

  5. Iodine: It's Important in Patients that Require Parenteral Nutrition

    NARCIS (Netherlands)

    Zimmermann, M.B.

    2009-01-01

    Iodine deficiency has multiple adverse effects on growth and development because of inadequate thyroid hormone production. Four methods are generally recommended for assessment of iodine nutrition: urinary iodine concentration, thyroid size, and blood concentrations of thyroid-stimulating hormone

  6. Abstraction of iodine from aromatic iodides by alkyl radicals: steric and electronic effects.

    Science.gov (United States)

    Dolenc, Darko; Plesnicar, Bozo

    2006-10-13

    Abstraction of the iodine atom from aryl iodides by alkyl radicals takes place in some cases very efficiently despite the unfavorable difference in bond dissociation energies of C-I bonds in alkyl and aryl iodides. The abstraction is most efficient in iodobenzenes, ortho-substituted with bulky groups. The ease of abstraction can be explained by the release of steric strain during the elimination of the iodine atom. The rate of abstraction correlates fairly well with the strain energy, calculated by density functional theory (DFT) and Hartree-Fock (HF) methods as a difference in the total energy of ortho and para isomers. However, besides the steric bulk, the presence of some other functional groups in an ortho substituent also influences the rate. The stabilization of the transition state, resembling a 9-I-2 iodanyl radical, by electron-withdrawing groups seems to explain a positive sign of the Hammett rho value in the radical abstraction of halogen atoms.

  7. [Dissociative identity disorder or schizophrenia?].

    Science.gov (United States)

    Tschöke, S; Steinert, T

    2010-01-01

    We present a case of dissociative identity disorder in which Schneiderian first rank symptoms were present besides of various states of consciousness. Thus the diagnosis of schizophrenia had to be considered. Formally, the symptoms met ICD-10 criteria for schizophrenia. However, taking into account the lack of formal thought disorder and of negative symptoms as well as a typical history of severe and prolonged traumatisation, we did not diagnose a co-morbid schizophrenic disorder. There is good evidence for the existence of psychotic symptoms among patients with dissociative disorders. However, in clinical practice this differential diagnosis is rarely considered.

  8. Diffraction dissociation at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Jenkovszky, Laszlo [Bogolyubov Institute for Theoretical Physics (BITP), Ukrainian National Academy of Sciences 14-b, Metrolohichna str., Kiev, 03680, Ukraine and Wigner Research Centre for Physics, Hungarian Academy of Sciences 1525 Budapest, POB 49 (Hungary); Orava, Risto [Institute of Physics, Division of Elementary Particle Physics, P.O. Box 64 (Gustaf Haellstroeminkatu 2a), FI-00014 University of Helsinki, Finland and CERN, CH-1211 Geneva 23 (Switzerland); Salii, Andrii [Bogolyubov Institute for Theoretical Physics (BITP), Ukrainian National Academy of Sciences 14-b, Metrolohichna str., Kiev, 03680 (Ukraine)

    2013-04-15

    We report on recent calculations of low missing mass single (SD) and double (DD) diffractive dissociation at LHC energies. The calculations are based on a dual-Regge model, dominated by a single Pomeron exchange. The diffractively excited states lie on the nucleon trajectory N*, appended by the isolated Roper resonance. Detailed predictions for the squared momentum transfer and missing mass dependence of the differential and integrated single-and double diffraction dissociation in the kinematical range of present and future LHC measurements are given.

  9. Diffraction dissociation at the LHC

    International Nuclear Information System (INIS)

    Jenkovszky, László; Orava, Risto; Salii, Andrii

    2013-01-01

    We report on recent calculations of low missing mass single (SD) and double (DD) diffractive dissociation at LHC energies. The calculations are based on a dual-Regge model, dominated by a single Pomeron exchange. The diffractively excited states lie on the nucleon trajectory N*, appended by the isolated Roper resonance. Detailed predictions for the squared momentum transfer and missing mass dependence of the differential and integrated single-and double diffraction dissociation in the kinematical range of present and future LHC measurements are given.

  10. Dissociative symptoms and dissociative disorders comorbidity in obsessive compulsive disorder: Symptom screening, diagnostic tools and reflections on treatment

    OpenAIRE

    Belli, Hasan

    2014-01-01

    Borderline personality disorder, conversion disorder and obsessive compulsive disorder frequently have dissociative symptoms. The literature has demonstrated that the level of dissociation might be correlated with the severity of obsessive compulsive disorder (OCD) and that those not responding to treatment had high dissociative symptoms. The structured clinical interview for DSM-IV dissociative disorders, dissociation questionnaire, somatoform dissociation questionnaire and dissociative expe...

  11. The processing of used cooking oil (yellow grease) using combination of adsorption and ultrafiltration membrane processes

    Science.gov (United States)

    Rosnelly, C. M.; Sofyana; Amalia, D.; Sarah, S.

    2018-03-01

    Yellow grease is used cooking oil whose quality has degraded due to the oxidation, polymerization, or hydrolysis process. In previous studies, yellow grease refining had been conducted either by adsorption or by using membrane. In this study, adsorption process using adsorbent from bagasse activated with H3PO4 12.5%, and ultrafiltration using Polyethersulfone (PES) membrane were combined. In adsorption stage, several variation of bagasse mass was fed into 200 ml of yellow grease and stirred for 60 minutes at 60 rpm. Yellow grease produced from adsorption with best condition was then processed using ultrafiltration membran that is PES membran with concentration by 15 wt % with transmembrane pressure variation by 0.5; 1; 1.5; 2; and 2.5 Bar. Analysis of yellow grease characteristics before refined showed its acid number, peroxide number, iodine number, and water content respectively by 2.68 mgKOH/Kg; 5.97 Meq/Kg; 51,48; and 1.29%. Characteristics of yellow grease after adsorption at its best condition on the parameters of acid number, peroxide number, iodine number, and water content are respectively by 2.55 mgKOH/Kg; 4.19 Meq/Kg; 40,02; and 0.27%. Characteristics of yellow grease after ultrafiltration at its best condition on the parameters of acid number, peroxide number, iodine number, and water content are respectively by 1.12 mgKOH/Kg; 1.8 Meq/Kg; 41,36; and 0.02%. Combination of adsorption and ultrafiltration processes for yellow grease processing showed decreasing value on the parameters of acid number, peroxide number, and water content that conforms to the SNI quality standard, but has not been able to increase the iodine number.

  12. FDA regulations regarding iodine addition to foods and labeling of foods containing added iodine12

    Science.gov (United States)

    Trumbo, Paula R

    2016-01-01

    The US Food and Drug Administration (FDA) regulates the addition of iodine to infant formulas, the iodization of salt, and the addition of salt and iodine to foods. The required amount of iodine in infant formulas is based on caloric content, and the label must provide the iodine content per 100 kcal. Cuprous iodide and potassium iodide may be added to table salt as a source of dietary iodine at a maximum amount of 0.01%; if added, the label must indicate that the salt is iodized. Table salt to which iodine has not been added must bear the statement, “This salt does not supply iodide, a necessary nutrient.” If a nutrient is to be appropriately added to a food for the purpose of correcting a dietary insufficiency, there should be sufficient scientific information available to demonstrate a nutritional deficiency and/or identify a public health problem. Furthermore, the population groups that would benefit from the proposed fortification should be identified. If iodine is added to a food, the percent Daily Value of iodine must be listed. There are no FDA regulations governing ingredient standards for dietary supplements. As a result, some dietary supplements include iodine and others do not. If a supplement contains iodine, the Supplement Facts label must list iodine as a nutrient ingredient. If iodine is not listed on the Supplement Facts label, then it has not been added. There are similarities between the FDA, which establishes US food regulations and policies, and the Codex Alimentarius (Codex), which develops international food standards and guidelines under the aegis of the FAO and the WHO. Both the FDA and Codex call for the labeling of table salt to indicate fortification with iodine, voluntary labeling of iodine on foods, and a Daily Value (called a Nutrient Reference Value by Codex) of 150 μg for iodine. PMID:27534626

  13. Serum thyroglobulin and urinary iodine concentration are the most appropriate indicators of iodine status and thyroid function under conditions of increasing iodine supply in schoolchildren in Benin

    NARCIS (Netherlands)

    van den Briel, T.; West, C. E.; Hautvast, J. G.; Vulsma, T.; de Vijlder, J. J.; Ategbo, E. A.

    2001-01-01

    Iodine deficiency control programs have greatly reduced iodine deficiency disorders worldwide. For monitoring changes in iodine status, different indicators may be used. The aim of this study was to evaluate the suitability of indicators of iodine status and thyroid function, thyroglobulin (Tg),

  14. A First Principles Study of H2 Adsorption on LaNiO3(001 Surfaces

    Directory of Open Access Journals (Sweden)

    Changchang Pan

    2017-01-01

    Full Text Available The adsorption of H2 on LaNiO3 was investigated using density functional theory (DFT calculations. The adsorption sites, adsorption energy, and electronic structure of LaNiO3(001/H2 systems were calculated and indicated through the calculated surface energy that the (001 surface was the most stable surface. By looking at optimized structure, adsorption energy and dissociation energy, we found that there were three types of adsorption on the surface. First, H2 molecules completely dissociate and then tend to bind with the O atoms, forming two –OH bonds. Second, H2 molecules partially dissociate with the H atoms bonding to the same O atom to form one H2O molecule. These two types are chemical adsorption modes; however, the physical adsorption of H2 molecules can also occur. When analyzing the electron structure of the H2O molecule formed by the partial dissociation of the H2 molecule and the surface O atom, we found that the interaction between H2O and the (001 surface was weaker, thus, H2O was easier to separate from the surface to create an O vacancy. On the (001 surface, a supercell was constructed to accurately study the most stable adsorption site. The results from analyses of the charge population; electron localization function; and density of the states indicated that the dissociated H and O atoms form a typical covalent bond and that the interaction between the H2 molecule and surface is mainly due to the overlap-hybridization among the H 1s, O 2s, and O 2p states. Therefore, the conductivity of LaNiO3(001/H2 is stronger after adsorption and furthermore, the conductivity of the LaNiO3 surface is better than that of the LaFeO3 surface.

  15. Environmental sciences: general. 1. Evaluation of Iodine Reactions with Nuclear Aerosols by DRIFT

    International Nuclear Information System (INIS)

    Riggs, C.A.; Tompson, R.V.; Ghosh, T.K.; Loyalka, S.K.

    2001-01-01

    Nuclear source term computations require databases for iodine vapor reactions with cesium compounds. We have explored measurements of iodine vapor [I 2(g) ] reactions with cesium carbonate particles [CsCO 3(s) ] using diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy in the far infrared region for iodine vapor concentrations typical of post-transient conditions in a pressurized water reactor containment. Cesium hydroxide (CsOH) in aerosol form is likely a significant source of radio-cesium released during a reactor transient. As shown in Eq. (1), CsOH (s) particles can combine with iodine gas to form cesium iodide [CsI (s) ] particles. Equations (2) and (3) present a two-step method where the CsOH (s) particles combine with carbon dioxide [CO 2(g) ] found in air to form Cs 2 CO 3(s) particles, which then react with iodine gas to form CsI (s) particles: I 2(g) + 4CsOH (s) ↔ 2CsI (s) 12CsO (s) 12H 2 O (l) , (1) CO 2(g) 12CsOH (s) ↔ Cs 2 CO 3(s) + H 2 O, (2) and Cs 2 CO 3(s) 13I 2(g) ↔ 5CsI (s) + CsIO 3(s) + 3CO 2(g) . (3) We elected to study reactions with Cs 2 CO 3(s) rather than CsOH (s) particles because of significant analytical and handling challenges with the DRIFT attachment presented by the corrosive characteristics of CsOH (s) particles. Physical modifications to the DRIFT attachment, in addition to improved handling practices, need to be evaluated prior to proceeding with the study of CsOH (s) by this method. The reaction of cesium carbonate agglomerates with iodine could occur by surface adsorption and/or absorption. Physical adsorption depends on the surface area and porosity of the solid material. Chemical adsorption depends on the chemical properties of both the gas and the solid material. Beahm et al. previously used classical wet chemical methods to monitor the reaction products after the reaction occurred. The use of DRIFT allows the study of the predicted physical and chemical adsorption occurring on the Cs 2 CO 3(s) surface

  16. Dissociative symptoms and neuroendocrine dysregulation in depression.

    Science.gov (United States)

    Bob, Petr; Fedor-Freybergh, Peter; Jasova, Denisa; Bizik, Gustav; Susta, Marek; Pavlat, Josef; Zima, Tomas; Benakova, Hana; Raboch, Jiri

    2008-10-01

    Dissociative symptoms are traditionally attributed to psychological stressors that produce dissociated memories related to stressful life events. Dissociative disorders and dissociative symptoms including psychogenic amnesia, fugue, dissociative identity-disorder, depersonalization, derealization and other symptoms or syndromes have been reported as an epidemic psychiatric condition that may be coexistent with various psychiatric diagnoses such as depression, schizophrenia, borderline personality disorder or anxiety disorders. According to recent findings also the somatic components of dissociation may occur and influence brain, autonomic and neuroendocrine functions. At this time there are only few studies examining neuroendocrine response related to dissociative symptoms that suggest significant dysregulation of the hypothalamus-pituitary-adrenal (HPA) axis. The aim of the present study is to perform examination of HPA axis functioning indexed by basal cortisol and prolactin and test their relationship to psychic and somatoform dissociative symptoms. Basal cortisol and prolactin and psychic and somatoform dissociative symptoms were assessed in 40 consecutive inpatients with diagnosis of unipolar depression mean age 43.37 (SD=12.21). The results show that prolactin and cortisol as indices of HPA axis functioning manifest significant relationship to dissociative symptoms. Main results represent highly significant correlations obtained by simple regression between psychic dissociative symptoms (DES) and serum prolactin (R=0.55, p=0.00027), and between somatoform dissociation (SDQ-20) and serum cortisol (R=-0.38, p=0.015). These results indicate relationship between HPA-axis reactivity and dissociative symptoms in unipolar depressive patients that could reflect passive coping behavior and disengagement.

  17. Methodology study for fixation of radioactive iodine in polymeric substrate for brachytherapy sources

    International Nuclear Information System (INIS)

    Rodrigues, Bruna T.; Rostelato, Maria Elisa C.M.; Souza, Carla D.; Tiezzi, Rodrigo; Souza, Daiane B. de; Benega, Marcos A.G.; Souza, Anderson S. de; Peleias Junior, Fernando S.; Zeituni, Calos A.; Fernandes, Vagner; Melo, Emerson Ronaldo de; Camargo, Anderson Rogerio de

    2015-01-01

    Cancer is now the second leading cause of death by disease in several countries, including Brazil. Prostate cancer is the most common among men. Brachytherapy is a modality of radiotherapy in which radioactive seeds are placed inside or in contact with the organ to be treated. The most widely used radioisotope in prostate brachytherapy is Iodine-125 which is presented fixated on a silver substrate that is subsequently placed inside a titanium capsule. A large dose of radiation is released only in the targeted tumor protecting healthy surrounding tissues. The technique requires the application of 80 - 120 seeds per patient. The implants of seeds have low impact and non-surgical procedures. Most patients can return to normal life within three days with little or no pain. This work proposes an alternative to the seeds that have already been developed, in order to reduce the cost by obtaining a better efficiency on fixing the radioactive iodine onto the epoxy resin. Methods have been developed to perform the fixation of Iodine-125 onto polymeric substrates. The parameters analyzed were the immersion time, type of static or dynamic reaction, concentration of the adsorption solution, the specific activity of the radioactive source, the need for carrier and chemical form of the radioactive Iodine. These experiments defined the most effective method to fixate the Iodine onto the polymeric material (epoxy resin), the Iodine activity in the polymeric substrate, the activity of the distribution of variation in a plot of polymeric cores and the efficiency of the epoxy resin to seal the seed. (author)

  18. Consuming iodine enriched eggs to solve the iodine deficiency endemic for remote areas in Thailand

    Directory of Open Access Journals (Sweden)

    Teeyapant Punthip

    2010-12-01

    Full Text Available Abstract Background Evidence showed that the occurrence of iodine deficiency endemic areas has been found in every provinces of Thailand. Thus, a new pilot programme for elimination of iodine deficiency endemic areas at the community level was designed in 2008 by integrating the concept of Sufficient Economic life style with the iodine biofortification of nutrients for community consumption. Methods A model of community hen egg farm was selected at an iodine deficiency endemic area in North Eastern part of Thailand. The process for the preparation of high content iodine enriched hen food was demonstrated to the farm owner with technical transfer in order to ensure the sustainability in the long term for the community. The iodine content of the produced iodine enriched hen eggs were determined and the iodine status of volunteers who consumed the iodine enriched hen eggs were monitored by using urine iodine excretion before and after the implement of iodine enrichment in the model farm. Results The content of iodine in eggs from the model farm were 93.57 μg per egg for the weight of 55 - 60 g egg and 97.76 μg for the weight of 60 - 65 g egg. The biological active iodo-organic compounds in eggs were tested by determination of the base-line urine iodine of the volunteer villagers before and after consuming a hard boiled iodine enriched egg per volunteer at breakfast for five days continuous period in 59 volunteers of Ban Kew village, and 65 volunteers of Ban Nong Nok Kean village. The median base-line urine iodine level of the volunteers in these two villages before consuming eggs were 7.00 and 7.04 μg/dL respectively. After consuming iodine enriched eggs, the median urine iodine were raised to the optimal level at 20.76 μg/dL for Ban Kew and 13.95 μg/dL for Ban Nong Nok Kean. Conclusions The strategic programme for iodine enrichment in the food chain with biological iodo-organic compound from animal origins can be an alternative method to

  19. Interfacial adsorption of insulin - Conformational changes and reversibility of adsorption

    NARCIS (Netherlands)

    Mollmann, SH; Jorgensen, L; Bukrinsky, JT; Elofsson, U; Norde, W; Frokjaer, S

    The adsorption of human insulin to Teflon particles was studied with respect to conformational changes and the reversibility of adsorption was examined by total internal reflection fluorescence (TIRF). Adsorption isotherms for the adsorption of human insulin indicated high affinity adsorption, even

  20. Dissociative Photoionization of 1-Halogenated Silacyclohexanes: Silicon Traps the Halogen.

    Science.gov (United States)

    Bodi, Andras; Sigurdardottir, Katrin Lilja; Kvaran, Ágúst; Bjornsson, Ragnar; Arnason, Ingvar

    2016-11-23

    The threshold photoelectron spectra and threshold photoionization mass spectra of 1-halogenated-1-silacyclohexanes, for the halogens X = F, Cl, Br, and I, have been obtained using synchrotron vacuum ultraviolet radiation and photoelectron photoion coincidence spectroscopy. As confirmed by a similar ionization onset and density functional theory molecular orbitals, the ionization to the ground state is dominated by electron removal from the silacyclohexane ring for X = F, Cl, and Br, and from the halogen lone pair for X = I. The breakdown diagrams show that the dissociative photoionization mechanism is also different for X = I. Whereas the parent ions decay by ethylene loss for X = F to Br in the low-energy regime, the iodine atom is lost for X = I. The first step is followed by a sequential ethylene loss at higher internal energies in each of the compounds. It is argued that the tendency of silicon to lower bond angles stabilizes the complex cation in which C 2 H 4 is η 2 -coordinated to it, and which precedes ethylene loss. Together with the relatively strong silicon-halogen bonds and the increased inductive effect of the silacyclohexane ring in stabilizing the cation, this explains the main differences observed in the fragmentation of the halogenated silacyclohexane and halogenated cyclohexane ions. The breakdown diagrams have been modeled taking into account slow dissociations at threshold and the resulting kinetic shift. The 0 K appearance energies have been obtained to within 0.08 eV for the ethylene loss for X = F to Br (10.56, 10.51, and 10.51 eV, respectively), the iodine atom loss for X = I (10.11 eV), the sequential ethylene loss for X = F to I (12.29, 12.01, 11.94, and 11.86 eV, respectively), and the minor channels of H loss for X = F (10.56 eV) and propylene loss in X = Cl (also at 10.56 eV). The appearance energies for the major channels likely correspond to the dissociative photoionization reaction energy.

  1. Experimental study on iodine chemistry (EXSI) - Containment experiments with elemental iodine

    International Nuclear Information System (INIS)

    Kaerkelae, T.; Auvinen, A.; Holm, J.; Ekberg, C.; Glaenneskog, H.

    2009-10-01

    The behaviour of iodine during a severe accident has been studied in several experimental programs, ranging from the large-scale PHEBUS FP tests and intermediate-scale ThAI tests to numerous separate effect studies. Oxidation of iodine in gas phase has been one of the greatest remaining uncertainties in iodine behaviour during a severe accident. In this study the possible formation of iodine oxide aerosol due to radiolytic oxidation of gaseous iodine is experimentally tested and the reaction products are analysed. The experimental facility applied in this study is based on the sampling system built at VTT for ISTP program project CHIP conducted IRSN. The experimental facility and the measuring technology are sophisticated and unique in the area of nuclear research as well as in the field of aerosol science. The results from the experiments show an extensive particle formation when ozone and gaseous iodine react with each other. The formed particles were collected on filters, while gaseous iodine was trapped into bubbles. The particles were iodine oxides and the size of particles was approximately 100 nm. The transport of gaseous iodine through the facility decreased when both gaseous iodine and ozone were fed together into facility. Experimental study on radiolytic oxidation of iodine was conducted in co-operation between VTT and Chalmers University of Technology as a part of the NKS-R programs. (author)

  2. Experimental study on iodine chemistry (EXSI) - Containment experiments with elemental iodine

    Energy Technology Data Exchange (ETDEWEB)

    Kaerkelae, T.; Auvinen, A. (VTT Technical Research Centre of Finland (Finland)); Holm, J.; Ekberg, C. (Chalmers Univ. of Technology (Sweden)); Glaenneskog, H. (Vattenfall Power Consultant (Sweden))

    2009-10-15

    The behaviour of iodine during a severe accident has been studied in several experimental programs, ranging from the large-scale PHEBUS FP tests and intermediate-scale ThAI tests to numerous separate effect studies. Oxidation of iodine in gas phase has been one of the greatest remaining uncertainties in iodine behaviour during a severe accident. In this study the possible formation of iodine oxide aerosol due to radiolytic oxidation of gaseous iodine is experimentally tested and the reaction products are analysed. The experimental facility applied in this study is based on the sampling system built at VTT for ISTP program project CHIP conducted IRSN. The experimental facility and the measuring technology are sophisticated and unique in the area of nuclear research as well as in the field of aerosol science. The results from the experiments show an extensive particle formation when ozone and gaseous iodine react with each other. The formed particles were collected on filters, while gaseous iodine was trapped into bubbles. The particles were iodine oxides and the size of particles was approximately 100 nm. The transport of gaseous iodine through the facility decreased when both gaseous iodine and ozone were fed together into facility. Experimental study on radiolytic oxidation of iodine was conducted in co-operation between VTT and Chalmers University of Technology as a part of the NKS-R programs. (author)

  3. Altering iodine metabolism in the calf by feeding iodine-binding agents

    International Nuclear Information System (INIS)

    Miller, J.K.; Swanson, E.W.; Lyke, W.A.; Byrne, W.F.

    1975-01-01

    Effects of feeding cottonseed meal and anion-exchange resin on iodine absorption and excretion by calves were investigated. Each additional amount of resin fed from 0.3 to 3.5 g/kg body weight further increased fecal excretion from single oral iodine-131 and intravenous iodine-125 doses. By feeding 3 to 10 g cottonseed meal/kg body weight, excretion of oral iodine-131 given daily was increased 7 to 94 percent in feces and reduced as much as 35 percent in urine, but plasma iodine-131 was not changed. Introducing 1 g resin/kg body weight daily into the diet increased fecal iodine-131 excretion three to five times that with cottonseed meal alone and reduced both plasma and urinary iodine-131. The same amount of resin fed daily had similar effects on excretion of iodine-131 injected subcutaneously each day. Although iodine depletion by a highly efficient iodine binder (resin) in the gastrointestinal tract is probable, iodine binding by a natural feed constituent (cottonseed meal) was relatively inefficient. (U.S.)

  4. Altering iodine metabolism in the calf by feeding iodine-binding agents

    International Nuclear Information System (INIS)

    Miller, J.K.; Swanson, E.W.; Lyke, W.A.; Byrne, W.F.

    1975-01-01

    Effects of feeding cottonseed meal and anion-exchange resin on iodine absorption and excretion by calves were investigated. Each additional amount of resin fed from 0.3 to 3.5 g/kg body weight further increased fecal excretion from single oral iodine-131 and intravenous iodine-125 doses. By feeding 3 to 10 g cottonseed meal/kg body weight, excretion of oral iodine-131 given daily was increased 7 to 94 percent in feces and reduced as much as 35 percent in urine, but plasma iodine-131 was not changed. Introducing 1 g resin/kg body weight daily into the diet increased fecal iodine-131 excretion three to five times that with cottonseed meal alone and reduced both plasma and urinary iodine-131. The same amount of resin fed daily had similar effects on excretion of iodine-131 injected subcutaneously each day. Although iodine depletion by a highly efficient iodine binder (resin) in the gastrointestinal tract is probable, iodine binding by a natural feed constituent (cottonseed meal) was relatively inefficient. (auth)

  5. DISSOCIATIVE DISORDERS IN DSM-5

    NARCIS (Netherlands)

    Spiegel, David; Loewenstein, Richard J.; Lewis-Fernandez, Roberto; Sar, Vedat; Simeon, Daphne; Vermetten, Eric; Cardena, Etzel; Dell, Paul F.

    Background: We present recommendations for revision of the diagnostic criteria for the Dissociative Disorders (DDs) for DSM-5. The periodic revision of the DSM provides an opportunity to revisit the assumptions underlying specific diagnoses and the empirical support, or lack of it, for the defining

  6. Hydrogen dissociation on metal surfaces

    NARCIS (Netherlands)

    Wijzenbroek, M.

    2016-01-01

    Dissociative chemisorption is an important reaction step in many catalytic reactions. An example of such a reaction is the Haber-Bosch process, which is used commercially to produce ammonia, an important starting material in the production of fertilisers. In theoretical descriptions of such chemical

  7. Energy localization and molecular dissociation

    International Nuclear Information System (INIS)

    Takeno, S.; Tsironis, G.P.

    2005-01-01

    We study analytically as well as numerically the role that large-amplitude vibrations play during the process of molecular dissociation. Our model consists of a linear three-atom molecule composed of identical atoms interacting with their nearest neighbors by Morse potentials. We find a close relation between energy localization and bond breaking and evaluate numerically the corresponding reaction paths

  8. Iodine content in bread and salt in Denmark after iodization and the influence on iodine intake

    DEFF Research Database (Denmark)

    Rasmussen, Lone Banke; Ovesen, Lars; Christensen, Tue

    2007-01-01

    Objective To measure the iodine content in bread and household salt in Denmark after mandatory iodine fortification was introduced and to estimate the increase in iodine intake due to the fortification. Design The iodine content in rye breads, wheat breads and salt samples was assessed. The incre......, and the current fortification level of salt ( 13 ppm) seems reasonable.......% of the rye breads and 90% of the wheat breads were iodized. The median iodine intake from bread increased by 25 ( 13-43) mu g/day and the total median iodine intake increased by 63 (36-104) mu g/day. Conclusions The fortification of bread and salt has resulted in a desirable increase in iodine intake...

  9. Method for immobilizing radioactive iodine

    International Nuclear Information System (INIS)

    Babad, H.; Strachan, D. M.

    1980-01-01

    Radioactive iodine, present as alkali metal iodides or iodates in an aqueous solution, is incorporated into an inert solid material for long-term storage by adding to the solution a stoichiometric amount with respect to the formation of a sodalite (3M2O.3Al2O3. 6SiO2.2MX, where M alkali metal; X I - or IO 3- ) of an alkali metal, alumina and silica, stirring the solution to form a homogeneous mixture, drying the mixture to form a powder, compacting and sintering the compacted powder at 1073 to 1373 K (800 0 to 1100 0 C.) for a time sufficient to form sodalite

  10. Iodine laser for fusion research

    International Nuclear Information System (INIS)

    Dance, B.

    1988-01-01

    The most powerful iodine laser in the world, known as Asterix IV, is being prepared for operation at The Max Plank-Institut fuer Quantenoptik at Garching, near Munich, in West Germany. It is expected to produce 2kJ pulses of 1ns duration. Shorter pulses of about 200 ps duration should be obtainable at power levels of over 5 TW. Pulses of maximum power will be available every 20 minutes; this frequency is expected to be adequate for fusion experiments, although the short rate could be raised if necessary by greater gas circulation and cooling. (Author)

  11. Iodine Absorption Cells Purity Testing

    Czech Academy of Sciences Publication Activity Database

    Hrabina, Jan; Zucco, M.; Philippe, Ch.; Pham, Minh Tuan; Holá, Miroslava; Acef, O.; Lazar, Josef; Číp, Ondřej

    2017-01-01

    Roč. 17, č. 1 (2017), s. 1-13, č. článku 17010102. ISSN 1424-8220 R&D Projects: GA ČR GA15-18430S; GA MŠk(CZ) LO1212; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : iodine cells * absorption spectroscopy * laser spectroscopy * laser standards * frequency stability Subject RIV: BH - Optics, Masers, Lasers OBOR OECD: Optics (including laser optics and quantum optics) Impact factor: 2.677, year: 2016

  12. Iodine stress corrosion cracking in Zircaloy

    International Nuclear Information System (INIS)

    Andrade, A.H.P. de; Pelloux, R.M.N.

    1983-01-01

    The subcritical growth of iodine-induced cracks in unirradiated Zircaloy plates is investigated as a function of the stress intensity factor K. The testing variables are: crystallographic texture (f-Number), microstructure (grain directionaly), heat treatment (stress relieved vs recrystallized plate), and temperature. The iodine partial pressure is 40Pa. (author) [pt

  13. 21 CFR 558.295 - Iodinated casein.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Iodinated casein. 558.295 Section 558.295 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... in Animal Feeds § 558.295 Iodinated casein. (a) Approvals. See 017762 in § 510.600(c) of this chapter...

  14. Iodine deficiency disorders in Sarawak, Malaysia.

    Science.gov (United States)

    Kiyu, A; Tambi, Z; Ahmad, Y

    1998-12-01

    The state of Sarawak in Malaysia has a high prevalence of iodine deficiency disorders (IDD). This has been revealed through a review of goitre surveys that were carried out in the State from the early 1970s to the 1990s. The primary cause was low iodine intake. Contributory factors were low iodine content in the soil and water as well as high cassava consumption. Virtual elimination of IDD is one of the nutritional goals of the IDD prevention and control programs. The strategies adopted include the iodination of coarse salt, which is sold in the market by shopkeepers and also provided free from government health clinics; legislation requiring that salt sold in IDD-gazetted areas must be iodised; and the use of iodinators to iodise water supplied by the gravity-feed system to villages and boarding schools in rural areas. The indicators used in the monitoring and evaluation of the program include the availability of iodised salt in the market and households, iodine levels in water supply that had been fitted with iodinators, goitre volume measured by ultrasound, and urinary iodine excretion among school children.

  15. Global functioning and disability in dissociative disorders.

    Science.gov (United States)

    Mueller-Pfeiffer, Christoph; Rufibach, Kaspar; Perron, Noelle; Wyss, Daniela; Kuenzler, Cornelia; Prezewowsky, Cornelia; Pitman, Roger K; Rufer, Michael

    2012-12-30

    Dissociative disorders are frequent comorbid conditions of other mental disorders. Yet, there is controversy about their clinical relevance, and little systematic research has been done on how they influence global functioning. Outpatients and day care patients (N=160) of several psychiatric units in Switzerland were assessed with the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV Axis I Disorders, Structured Clinical Interview for DSM-IV Dissociative Disorders, Global Assessment of Functioning Scale, and World Health Organization Disability Assessment Schedule-II. The association between subjects with a dissociative disorder (N=30) and functional impairment after accounting for non-dissociative axis I disorders was evaluated by linear regression models. We found a proportion of 18.8% dissociative disorders (dissociative amnesia=0%, dissociative fugue=0.6%, depersonalization disorder=4.4%, dissociative identity disorder=7.5%, dissociative disorder-not-otherwise-specified=6.3%) across treatment settings. Adjusted for other axis I disorders, subjects with a comorbid dissociative identity disorder or dissociative disorder-not-otherwise-specified had a median global assessment of functioning score that was 0.86 and 0.88 times, respectively, the score of subjects without a comorbid dissociative disorder. These findings support the hypothesis that complex dissociative disorders, i.e., dissociative identity disorder and dissociative disorder-not-otherwise-specified, contribute to functional impairment above and beyond the impact of co-existing non-dissociative axis I disorders, and that they qualify as "serious mental illness". Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  16. Adsorption. What else?

    OpenAIRE

    Rodrigues, Alirio E.

    2012-01-01

    [EN] Chemical Engineering today combines Molecular and Materials Engineerig and Process and Product Engineering (ChE=M2P2). Cyclic adsorptive processes (Simulated Moving Bed –SMB and Pressure Swing Adsorption-PSA) will be discussed for “old” and “new” applications making use of “old” and “new” (MOFs) adsorbent materials. After revisiting my memory as PhD student and the First Brazilian Adsorption meeting I will review the basic concepts involved in adsorption processes and then...

  17. Iodine budget in surface waters from Atacama: Natural and anthropogenic iodine sources revealed by halogen geochemistry and iodine-129 isotopes

    International Nuclear Information System (INIS)

    Álvarez, Fernanda; Reich, Martin; Snyder, Glen; Pérez-Fodich, Alida; Muramatsu, Yasuyuki; Daniele, Linda; Fehn, Udo

    2016-01-01

    Iodine enrichment in the Atacama Desert of northern Chile is widespread and varies significantly between reservoirs, including nitrate-rich “caliche” soils, supergene Cu deposits and marine sedimentary rocks. Recent studies have suggested that groundwater has played a key role in the remobilization, transport and deposition of iodine in Atacama over scales of millions-of-years. However, and considering that natural waters are also anomalously enriched in iodine in the region, the relative source contributions of iodine in the waters and its extent of mixing remain unconstrained. In this study we provide new halogen data and isotopic ratios of iodine ("1"2"9I/I) in shallow seawater, rivers, salt lakes, cold and thermal spring water, rainwater and groundwater that help to constrain the relative influence of meteoric, marine and crustal sources in the Atacama waters. Iodine concentrations in surface and ground waters range between 0.35 μM and 26 μM in the Tarapacá region and between 0.25 μM and 48 μM in the Antofagasta region, and show strong enrichment when compared with seawater concentrations (I = ∼0.4 μM). In contrast, no bromine enrichment is detected (1.3–45.7 μM for Tarapacá and 1.7–87.4 μM for Antofagasta) relative to seawater (Br = ∼600 μM). These data, coupled to the high I/Cl and low Br/Cl ratios are indicative of an organic-rich sedimentary source (related with an “initial” fluid) that interacted with meteoric water to produce a mixed fluid, and preclude an exclusively seawater origin for iodine in Atacama natural waters. Iodine isotopic ratios ("1"2"9I/I) are consistent with halogen chemistry and confirm that most of the iodine present in natural waters derives from a deep initial fluid source (i.e., groundwater which has interacted with Jurassic marine basement), with variable influence of at least one atmospheric or meteoric source. Samples with the lowest isotopic ratios ("1"2"9I/I from ∼215 to ∼1000 × 10"

  18. Methodology for iodine-129 determination in coniferous plant by neutron activation

    International Nuclear Information System (INIS)

    Quintana, E.E.; Thyssen, S.M.

    1998-01-01

    Full text: The measurement methods of iodine-129 ( 129 I) include liquid scintillation counting, mass spectrometry analysis, X-ray spectrometry and neutron activation analysis. The combination of long half-life and low radiation energy, limit the sensitivity of a direct measurement in environmental matrixes. The neutron activation analysis (NAA) permits the increase in the sensitivity because of the high thermal neutron cross section of 129 I. The reaction produced is 129 I (n,γ) 130 I and the Eγ (536 keV) of iodine-130 (t 1/2 = 12,6 hours) is measured. The developed methodology allows the determination of 129 I in coniferous needles using NAA. The chemical treatment removes the interferences present in the matrix, as well as the Bromine-82 originated in the activation process. The analytical method is divided in six steps: a) digestion by alkaline fusion; b) radiochemical purification of 129 I by distillation followed by solvent extraction; c) distillation and adsorption on activated charcoal; d) neutron irradiation; e) radiochemical purification of 130 I by distillation followed by solvent extraction; f) gamma spectrometry. Iodine-131 tracer is added, and a chemical recovery of 95% in the distillations is obtained. The whole process recovery is within 70% and 85%. The detection limit is 0.48 mBq. Several factors affect this value, such as sample type, variety of coniferous, natural iodine concentration, irradiation time and neutron flux. (author) [es

  19. Ab initio atomic simulation of hydrogen and iodine effects in zirconium

    International Nuclear Information System (INIS)

    Domain, Ch.

    2002-03-01

    In this work we present ab initio atomic simulations concerning the effects of hydrogen and iodine in hexagonal zirconium. We first studied the point defects in the dilute Zr-H (and to a less extend Zr-H-O) systems and concluded that it is better described within the generalised gradient approximation for the exchange and correlation functional. We calculated the hydrogen thermal diffusion coefficient in solid solution that agree very well with the experimental values. The calculated formation energy of different self-interstitial configuration are rather small (around 3 eV) and close to each other indicating the high complexity of these defects. We studied the core structure of the screw dislocation that has a preferential prismatic spreading. We also calculated the gamma surface for different gliding planes. The influence of hydrogen, that induces a significant reduction of the gamma surfaces excess energies, allows to qualitatively explain experimental results regarding some hydrogen effects on hexagonal zirconium plastic deformation. We also discussed the effect of zirconium hydride stoichiometry on gamma surfaces. The results concerning the iodine and oxygen adsorption on zirconium surfaces, inducing the evaluation of the effective surface energy reduction as a function of the iodine partial pressure allow for a better description of iodine induced stress corrosion cracking of zirconium. (author)

  20. The high-power iodine laser

    Science.gov (United States)

    Brederlow, G.; Fill, E.; Witte, K. J.

    The book provides a description of the present state of the art concerning the iodine laser, giving particular attention to the design and operation of pulsed high-power iodine lasers. The basic features of the laser are examined, taking into account aspects of spontaneous emission lifetime, hyperfine structure, line broadening and line shifts, stimulated emission cross sections, the influence of magnetic fields, sublevel relaxation, the photodissociation of alkyl iodides, flashlamp technology, excitation in a direct discharge, chemical excitation, and questions regarding the chemical kinetics of the photodissociation iodine laser. The principles of high-power operation are considered along with aspects of beam quality and losses, the design and layout of an iodine laser system, the scalability and prospects of the iodine laser, and the design of the single-beam Asterix III laser.

  1. Treatment of hyperthyroidism with radioactive iodine

    International Nuclear Information System (INIS)

    Bell, R.L.

    1974-01-01

    While radioactive iodine is clearly the therapy of choice for Graves' disease (even in younger patients) the use of radioactive iodine for therapy of the toxic multinodular or uninodular goiter presents an entirely different problem. Although these two entities can be treated with radioactive iodine provided there is some suppression of the tissue that is not autonomous, transient release of thyroid hormone may induce symptoms of thyroid storm in the very large multinodular toxic goiter treated with radioiodine therapy. These toxic nodules generally require much larger doses of radioiodine than is commonly used for classical Graves' disease and may either require fractional administration of radioisotopes or concomitant use of antithyroid drugs and iodides. In general, surgery remains the treatment of choice for large toxic multinodular goiters, after proper preparation by medical means including radioactive iodine. Radioactive iodine therapy for hyperthyroidism is contraindicated in pregnancy and generally is not used in children below five years of age. (U.S.)

  2. Iodine in eggs in an iodopenic region

    International Nuclear Information System (INIS)

    Bogdanov, Bogdan; Gonev, Mihail; Tadzher, Isak S.

    1996-01-01

    Macedonia is a region with a recognized precarious iodine balance, due to iodine deficiency in almost all water sources. Five percent iodine intake through eggs in the daily diet of adults is significant in this balance. The content of 40-220 micro g I - /kg eggs is lower than the British one (average 340-370 micro g I - /kg). The amount per egg is 3-6 micro g I' far less than 711 micro g I - in special iodine-enriched eggs designed for treatment of thyroid and metabolic disorders by feeding chickens with kelp additives. The iodine content of our manufacturers, provides substantial part of former Yugoslavia with eggs, is entirely dependent on imported fishmeal in chicken feed. (Author)

  3. Risk of suboptimal iodine intake in pregnant Norwegian women.

    Science.gov (United States)

    Brantsæter, Anne Lise; Abel, Marianne Hope; Haugen, Margaretha; Meltzer, Helle Margrete

    2013-02-06

    Pregnant women and infants are exceptionally vulnerable to iodine deficiency. The aims of the present study were to estimate iodine intake, to investigate sources of iodine, to identify predictors of low or suboptimal iodine intake (defined as intakes below 100 μg/day and 150 μg/day) in a large population of pregnant Norwegian women and to evaluate iodine status in a sub-population. Iodine intake was calculated based on a validated Food Frequency Questionnaire in the Norwegian Mother and Child Cohort. The median iodine intake was 141 μg/day from food and 166 μg/day from food and supplements. Use of iodine-containing supplements was reported by 31.6%. The main source of iodine from food was dairy products, contributing 67% and 43% in non-supplement and iodine-supplement users, respectively. Of 61,904 women, 16.1% had iodine intake below 100 μg/day, 42.0% had iodine intake below 150 μg/day and only 21.7% reached the WHO/UNICEF/ICCIDD recommendation of 250 μg/day. Dietary behaviors associated with increased risk of low and suboptimal iodine intake were: no use of iodine-containing supplements and low intake of milk/yogurt, seafood and eggs. The median urinary iodine concentration measured in 119 participants (69 μg/L) confirmed insufficient iodine intake. Public health strategies are needed to improve and secure the iodine status of pregnant women in Norway.

  4. Dissociative Functions in the Normal Mourning Process.

    Science.gov (United States)

    Kauffman, Jeffrey

    1994-01-01

    Sees dissociative functions in mourning process as occurring in conjunction with integrative trends. Considers initial shock reaction in mourning as model of normal dissociation in mourning process. Dissociation is understood to be related to traumatic significance of death in human consciousness. Discerns four psychological categories of…

  5. Correlations in the hadronic double diffractive dissociation

    International Nuclear Information System (INIS)

    Goldegol, Alexandre.

    1991-05-01

    A given reaction of double diffractive dissociation is studied based on the three-component Deck Model. The correlations among the diffractive slope, the effective mass of the dissociated particle sub-system and the dissociation angle in the Gottfried-Jackson are studied based in this model. 9 refs, 19 figs

  6. First-principles investigations of O2 dissociation on low-coordinated Pd ensembles over stepped Au surfaces

    International Nuclear Information System (INIS)

    Yuan, D.W.; Liu, Z.R.; Xu, Y.

    2012-01-01

    The adsorption and dissociation of O 2 on Pd monomer or trimer incorporated into Au(322) and Au(321) surfaces are systematically investigated by first-principles calculations and nudged-elastic-band simulations. We found that the contiguous low-coordinated Pd ensembles alloyed into step edges of Au surfaces are required for O 2 dissociation with an enhanced adsorption energy (∼−1.00 eV). The dissociative barrier of O 2 is mainly related to the size of Pd ensembles, and the activation energy is about 1.00 eV on Pd trimers. However, the Pd monomer is less active for the adsorption and dissociation of O 2 . Additionally, the O spillover from Pd to Au sites only occurs at elevated temperature, and the diffusion processes are highly endothermic. The calculated results indicate that the Pd-modified Au step edge with a contiguous Pd ensemble is the reactive center for supplying atomic oxygen on Pd-doped Au catalysts. -- Highlights: ► Our results reveal the mechanism of O 2 dissociation on Pd-decorated stepped Au surfaces. ► The adsorption energy of O 2 is related to both coordination numbers and geometrical arrangements of Pd atoms alloyed into Au surface. ► The Pd-modified Au step with a contiguous Pd ensemble is the reactive center for O 2 dissociation. ► Our results are important for understanding the catalytic properties of Pd-modified nanoporous gold, especially for those catalytic reactions related to O 2 activation.

  7. Mercury separation from concentrated potassium iodide/iodine leachate using Self-Assembled Mesoporous Mercaptan Support (SAMMS) technology

    International Nuclear Information System (INIS)

    Mattigod, S.V.; Feng, X.; Fryxell, G.E.

    1997-10-01

    A study was conducted to demonstrate the effectiveness of a novel adsorber, the Self-Assembled Mesoporous Mercaptan Support (SAMMS) material to remove mercury (Hg) from potassium iodide/iodine (KI/I 2 ) waste streams. This study included investigations of the SAMMS material''s binding kinetics, loading capacity, and selectivity for Hg adsorption from surrogate and actual KI/I 2 waste solutions. The kinetics data showed that binding of Hg by the adsorber material occurs very rapidly, with 82% to 95% adsorption occurring within the first 5 min. No significant differences in the rate of adsorption were noted between pH values of 5 and 9 and at Hg concentrations of ∼100 mg/1. Within the same range of pH values, an approximate four-fold increase in initial Hg concentration resulted in a two-fold increase in the rate of adsorption. In all cases studied, equilibrium adsorption occured within 4 h. The loading capacity experiments in KI/I 2 surrogate solutions indicated Hg adsorption densities between 26 to 270 mg/g. The loading density increased with increasing solid: solution ratio and decreasing iodide concentrations. Values of distribution coefficients (1.3x10 5 to >2.6x10 8 ml/g) indicated that material adsorbs Hg with very high specificity from KI/I 2 surrogate solutions. Reduction studies showed that compared to metallic iron (Fe), sodium dithionite can very rapidly reduce iodine as the triiodide species into the iodide form. Adsorption studies conducted with actual KI/I 2 leachates confirmed the highly specific Hg adsorption properties (K d >6x10 7 to>1x10 8 ml//g) of the adsorber material. Following treatment, the Hg concentrations in actual leachates were below instrumental detection limits (i.e., < 0.00005 mg/l), indicating that the KI solutions can be recycled

  8. Overview of the ACEX project iodine work

    Energy Technology Data Exchange (ETDEWEB)

    Merilo, M

    1996-12-01

    The ACEX project is an internationally sponsored research program that focuses on several aspects of severe accidents. The areas addressed are iodine behavior in containments, pool scrubbing, molten corium concrete interactions, and ex-vessel core debris coolability. These areas all represent extensions to the previous and current ACE and MACE programs respectively. The ACE-Phase B (iodine) project, and other recent research efforts, have clarified the roles of the important phenomena that influence iodine volatility in reactor containments during severe accidents. The ACE Iodine Chemistry Subcommittee concluded that even though enough data has been generated to support reasonably good quantification of the important phenomena, a few important areas remain where quantification is still uncertain. This is due to a lack of agreement on how to utilize the existing database, as well as the possible absence of critical test and/or property data. Technical resolution of the overall iodine behavior issue is therefore not feasible until these uncertainties are fully assessed and practical solutions have been identified, implemented, and verified. The overall objectives of the ACEX iodine research program are to ensure that the iodine database can be used to predict the airborne concentration of iodine, the conditions for iodine reservoir stability, and to provide a mechanistic understanding for these phenomena. The first phase of this work involves a comprehensive review and interpretation of the existing database in order to formulate practical strategies for dealing with significant uncertainties and/or deficiencies. Several projects are underway involving the effects of organic reactions and structural surface interactions. In addition effort is being expended on standardizing the aqueous iodine kinetics database, specifying useful mass transfer models, and defining methodology for pH prediction. (Abstract Truncated)

  9. Content iodine in sauces of type emulsion

    Directory of Open Access Journals (Sweden)

    M. Bakirov

    2015-05-01

    Full Text Available Introduction. The scarcity of natural resources arouse a necessity to find additional sources of protein, fat, carbohydrates, and their complexes with scarce mineral compounds. Therefore, a relevant issue is to enrich the diets deficient iodine compounds through research and development of new food products. Materials and methods. Investigation of iodine content in emulsion-type sauces at all stages was performed using Xray -fluorescence analyzer «Elvax». X-ray -fluorescence method consists of the appearance characteristic X-radiation of atoms of a chemical element at infringement they the primary X-ray irradiation. Results and discussion. Investigated for the determination of organic and inorganic forms of iodine in content of food items, and installed the total loss of iodine in sauces after cooking and storage at +5 ... +10 ° C for 30 days. Using iodine-proteinaceous additive from 0.5 ... 2.5% by mass of iodine 0.01% can be achieved from 15 to 50% of the human daily requirement by iodine. The resulting product does not lose its organoleptic, physico - chemical, consumer characteristics and meets the requirements of normative documents. As a result of our research, it was found that the addition of the supplements enriched protein-mineral (SEPM in composition sauces does not adversely affect the physical -chemical characteristics of sauces, but due to the stabilizing effect of additives iodine-proteinaceous increased emulsion stability up to 98 - 100% without additional foo d additives (emulsifiers. This additive has passed a series of tests that indicate on compliance with requirements normative and technical documentation. Conclusions. Used methodical approach allowed us to estimate the level of organic and inorganic iodine, as well as describe in more detail and correctly interpret the chemical composition of foods fortified with iodine and predict their health properties.

  10. Overview of the ACEX project iodine work

    International Nuclear Information System (INIS)

    Merilo, M.

    1996-01-01

    The ACEX project is an internationally sponsored research program that focuses on several aspects of severe accidents. The areas addressed are iodine behavior in containments, pool scrubbing, molten corium concrete interactions, and ex-vessel core debris coolability. These areas all represent extensions to the previous and current ACE and MACE programs respectively. The ACE-Phase B (iodine) project, and other recent research efforts, have clarified the roles of the important phenomena that influence iodine volatility in reactor containments during severe accidents. The ACE Iodine Chemistry Subcommittee concluded that even though enough data has been generated to support reasonably good quantification of the important phenomena, a few important areas remain where quantification is still uncertain. This is due to a lack of agreement on how to utilize the existing database, as well as the possible absence of critical test and/or property data. Technical resolution of the overall iodine behavior issue is therefore not feasible until these uncertainties are fully assessed and practical solutions have been identified, implemented, and verified. The overall objectives of the ACEX iodine research program are to ensure that the iodine database can be used to predict the airborne concentration of iodine, the conditions for iodine reservoir stability, and to provide a mechanistic understanding for these phenomena. The first phase of this work involves a comprehensive review and interpretation of the existing database in order to formulate practical strategies for dealing with significant uncertainties and/or deficiencies. Several projects are underway involving the effects of organic reactions and structural surface interactions. In addition effort is being expended on standardizing the aqueous iodine kinetics database, specifying useful mass transfer models, and defining methodology for pH prediction. The results of this work are expected to identify where additional data

  11. Effect of transition metal-doped Ni(211) for CO dissociation: Insights from DFT calculations

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Kuiwei; Zhang, Minhua [Key Laboratory for Green Chemical Technology of Ministry of Education, R& D Center for Petrochemical Technology, Tianjin University, Tianjin 300072 (China); Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072 (China); Yu, Yingzhe, E-mail: yzhyu@tju.edu.cn [Key Laboratory for Green Chemical Technology of Ministry of Education, R& D Center for Petrochemical Technology, Tianjin University, Tianjin 300072 (China)

    2017-03-31

    Highlights: • Doping the step edge of Ni(211) with Fe or Ru observably enhances CO dissociation. • Rh doping is unfavorable for CO activation both kinetically and thermodynamically. • Two neat linear relations are proposed besides the Brønsted–Evans–Polanyi relation. • The differences of CO adsorption are rationalized via the Blyholder model. - Abstract: Density functional theory slab calculations were performed to investigate the adsorption and dissociation of CO over pure and M-doped Ni(211) (M = Fe, Co, Ru and Rh) with the aim to elucidate the effect of transition metal doping for CO activation. Doping the step edge of Ni(211) with Fe, Co and Ru is found to enhance the binding of CO in the initial state (IS) (in the sequence by the improvement degree: Fe > Ru > Co) as well as the co-adsorption of C and O in the final state (FS) (Ru > Fe > Co). In contrast, Rh doping is unfavorable both in the IS and in the FS. Analysis of the overall potential energy surfaces (PES) suggests CO dissociation is facilitated by Fe, Ru and Co doping both kinetically and thermodynamically, wherein Fe and Ru behave extraordinary. Interestingly, Fe substitute is slightly superior to Ru in kinetics whereas the contrary is the case in thermodynamics. Rh doping elevates the energy height from 0.97 eV on Ni(211) to 1.32 eV and releases 0.39 eV less heat relative to Ni(211), again manifesting a negative effect. Besides the classical Brønsted–Evans–Polanyi relationship, we put forward another two neat linear relations, which can well describe the feature of CO dissociation. The differences of CO adsorption and activation in the IS over pure and doped Ni(211) surfaces are rationalized via electronic structure analysis. The findings presented herein are expected to provide theoretical guidance for catalyst design and optimization in relevant processes.

  12. Adsorption chromatographic separation of radioiodine-labelled compounds using binary eluents

    International Nuclear Information System (INIS)

    Toth, G.

    1980-01-01

    An adsorption chromatographic method using Sephadex LH-20 dextran gel as adsorbent and water-organic solvent binary eluents was developed for the systematic separation of low molecular weight radioiodine-labelled substances like iodothyronines, iodobenzoic acids and iodotyrosine methyl ester derivatives of prostaglandins, steroids etc. The adsorbed iodine compounds were separated by water-organic solvent mixture, and the order of the compounds is in accordance with the increasing number of iodine substituents per molecule. A method is reported which enables the calculation of the eluent strength of the water-organic solvent eluents. (author)

  13. Edge reactivity and water-assisted dissociation on cobalt oxide nanoislands

    International Nuclear Information System (INIS)

    Fester, J.; García-Melchor, M.; Walton, A. S.; Bajdich, M.

    2017-01-01

    Here, transition metal oxides show great promise as Earth-abundant catalysts for the oxygen evolution reaction in electrochemical water splitting. However, progress in the development of highly active oxide nanostructures is hampered by a lack of knowledge of the location and nature of the active sites. Here we show, through atom-resolved scanning tunnelling microscopy, X-ray spectroscopy and computational modelling, how hydroxyls form from water dissociation at under coordinated cobalt edge sites of cobalt oxide nanoislands. Surprisingly, we find that an additional water molecule acts to promote all the elementary steps of the dissociation process and subsequent hydrogen migration, revealing the important assisting role of a water molecule in its own dissociation process on a metal oxide. Inspired by the experimental findings, we theoretically model the oxygen evolution reaction activity of cobalt oxide nanoislands and show that the nanoparticle metal edges also display favourable adsorption energetics for water oxidation under electrochemical conditions.

  14. Dissociation dynamics of CH3I in electric spark induced breakdown revealed by time-resolved laser induced breakdown spectroscopy

    International Nuclear Information System (INIS)

    Wang, Yang; Liu, Wei-long; Song, Yun-fei; Duo, Li-ping; Liu, Yu-qiang; Yang, Yan-qiang

    2015-01-01

    Highlights: • Emission of electric spark dissociation of CH 3 I is similar to its fs LIBS. • We use fs laser induced breakdown as a simulation for electric spark dissociation. • The I 2 molecule formation is directly observed in the time-resolved LIBS. • Bimolecular collision of I ∗ and CH 3 I is responsible for the formation of I 2 . - Abstract: The electric discharge spark dissociation of gas CH 3 I is found to be similar to its femtosecond laser photodissociation. The almost identical spectra of the two processes show that their initial ionization conditions are very similar. The initial ionization followed by molecular fragmentation is proposed as the dissociation mechanism, in which the characteristic emissions of I + , CH 3 , CH 2 , CH, H, and I 2 are identified as the dissociation products. The emission band of 505 nm I 2 is clearly observed in the time-resolved laser induced breakdown spectroscopy (LIBS). The dynamic curve indicates that I 2 ∗ molecules are formed after the delay time of ∼4.7 ns. The formation of I 2 ∗ molecule results from the bimolecular collision of the highly excited iodine atom I ∗ ( 4 P) and CH 3 I molecule. This dynamical information can help understand the process of electric discharge spark dissociation of CH 3 I

  15. Low-level seaweed supplementation improves iodine status in iodine-insufficient women.

    Science.gov (United States)

    Combet, Emilie; Ma, Zheng Feei; Cousins, Frances; Thompson, Brett; Lean, Michael E J

    2014-09-14

    Iodine insufficiency is now a prominent issue in the UK and other European countries due to low intakes of dairy products and seafood (especially where iodine fortification is not in place). In the present study, we tested a commercially available encapsulated edible seaweed (Napiers Hebridean Seagreens® Ascophyllum nodosum species) for its acceptability to consumers and iodine bioavailability and investigated the impact of a 2-week daily seaweed supplementation on iodine concentrations and thyroid function. Healthy non-pregnant women of childbearing age, self-reporting low dairy product and seafood consumption, with no history of thyroid or gastrointestinal disease were recruited. Seaweed iodine (712 μg, in 1 g seaweed) was modestly bioavailable at 33 (interquartile range (IQR) 28-46) % of the ingested iodine dose compared with 59 (IQR 46-74) % of iodine from the KI supplement (n 22). After supplement ingestion (2 weeks, 0·5 g seaweed daily, n 42), urinary iodine excretion increased from 78 (IQR 39-114) to 140 (IQR 103-195) μg/l (Pseaweed was palatable and acceptable to consumers as a whole food or as a food ingredient and effective as a source of iodine in an iodine-insufficient population. In conclusion, seaweed inclusion in staple foods would serve as an alternative to fortification of salt or other foods with KI.

  16. Urinary Iodine Clearance following Iodinated Contrast Administration: A Comparison of Euthyroid and Postthyroidectomy Subjects

    Directory of Open Access Journals (Sweden)

    Janice D. Ho

    2014-01-01

    Full Text Available Purpose. To compare iodine clearance following iodinated contrast administration in thyroidectomised thyroid cancer patients and euthyroid individuals. Methods. A convenience population (6 thyroidectomised thyroid cancer patients and 7 euthyroid controls was drawn from patients referred for iodinated contrast-enhanced computed tomography (CT studies. Subjects had sequential urine samples collected up to 6 months (50 samples from the thyroidectomised and 63 samples from the euthyroid groups. t-tests and generalised estimating equations (GEE were used to test for group differences in urinary iodine creatinine ratios. Results. Groups had similar urinary iodine creatinine ratios at baseline, with a large increase 2 weeks following iodinated contrast (P=0.005. Both groups had a return of urinary iodine creatinine ratios to baseline by 4 weeks, with no significant group differences overall or at any time point. Conclusions. Thyroidectomised patients did not have a significantly different urinary iodine clearance than euthyroid individuals following administration of iodinated contrast. Both had a return of urinary iodine creatinine ratios to baseline within 4 weeks.

  17. A Simple Adsorption Experiment

    Science.gov (United States)

    Guirado, Gonzalo; Ayllon, Jose A.

    2011-01-01

    The study of adsorption phenomenon is one of the most relevant and traditional physical chemistry experiments performed by chemistry undergraduate students in laboratory courses. In this article, we describe an easy, inexpensive, and straightforward way to experimentally determine adsorption isotherms using pieces of filter paper as the adsorbent…

  18. Controlled swelling and adsorption properties of polyacrylate/montmorillonite composites

    Energy Technology Data Exchange (ETDEWEB)

    Natkanski, Piotr [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland); Kustrowski, Piotr, E-mail: kustrows@chemia.uj.edu.pl [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland); Bialas, Anna; Piwowarska, Zofia [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland); Michalik, Marek [Institute of Geological Sciences, Jagiellonian University, Oleandry 2a, 30-063 Krakow (Poland)

    2012-10-15

    A series of novel polyacrylate/montmorillonite composites was synthesized by in situ polymerization in aqueous slurry of clay. Dissociated (obtained by adding ammonium or sodium hydroxide) and undissociated forms of acrylic acid were used as monomers in the hydrogel synthesis. The structure and composition of the samples were studied by powder X-ray diffraction, diffuse reflectance infra-red Fourier transform spectroscopy, thermogravimetry and elemental analysis. It has been found that the kind of monomer influences strongly the location of a polymer chain in the formed composite. Complete intercalation of hydrogel into the interlayer space of montmorillonite was observed for sodium polyacrylate, whereas polyacrylic acid and ammonium polyacrylate mainly occupied the outer surface of the clay. The position of hydrogel determined the swelling and adsorption properties of the studied composites. The important factor influencing the kinetics of Fe(III) cation adsorption was pH. The analysis of adsorption isotherms allowed to propose the mechanism of Fe(III) cation adsorption. Highlights: Black-Right-Pointing-Pointer Polyacrylate hydrogels can be introduced into the interlayers of clay. Black-Right-Pointing-Pointer The position of hydrogel in the composite depends on the polymer type. Black-Right-Pointing-Pointer Ammonium polyacrylate places outside the clay, sodium one is intercalated into it. Black-Right-Pointing-Pointer Swelling and adsorption capacities can be controlled by the polymer position. Black-Right-Pointing-Pointer High adsorption efficiency in Fe(III) removal was observed.

  19. Radioactive nuclide adsorption

    International Nuclear Information System (INIS)

    Fukushima, Kimichika.

    1982-01-01

    Purpose: To improve the efficiency of a radioactive nuclide adsorption device by applying a nickel plating on a nickel plate to render the surface active. Constitution: A capturing device for radioactive nuclide such as manganese 54, cobalt 60, 58 and the like is disposed to the inside of a pipeway provided on the upper portion of fuel assemblies through which liquid sodium as the coolant for LMFBR type reactor is passed. The device comprises a cylindrical adsorption body and spacers. The adsorption body is made of nickel and applied with a nickel plating on the surface thereof. The surface of the adsorption body is unevened to result in disturbance in the coolant and thereby improve the adsorptive efficiency. (Kawakami, Y.)

  20. Radiative capture versus Coulomb dissociation

    International Nuclear Information System (INIS)

    Esbensen, H.; Physics

    2006-01-01

    Measurements of the Coulomb dissociation of 8 B have been used to infer the rate of the inverse radiative proton capture on 7 Be. The analysis is usually based on the assumptions that the two processes are related by detailed balance and described by E1 transitions. However, there are corrections to this relation. The Coulomb form factors for the two processes, for example, are not identical. There are also E2 transitions and higher-order effects in the Coulomb dissociation, and the nuclear induced breakup cannot always be ignored. While adding first-order E2 transitions enhances the decay energy spectrum, the other mechanisms cause a suppression at low relative energies. The net result may accidentally be close to the conventional first-order E1 calculation, but there are differences which cannot be ignored if accuracies of 10% or better are needed

  1. Radiative Capture versus Coulomb Dissociation

    International Nuclear Information System (INIS)

    Esbensen, Henning

    2006-01-01

    Measurements of the Coulomb dissociation of 8B have been used to infer the rate of the inverse radiative proton capture on 7Be. The analysis is usually based on the assumptions that the two processes are related by detailed balance and described by E1 transitions. However, there are corrections to this relation. The Coulomb form factors for the two processes, for example, are not identical. There are also E2 transitions and higher-order effects in the Coulomb dissociation, and the nuclear induced breakup cannot always be ignored. While adding first-order E2 transitions enhances the decay energy spectrum, the other mechanisms cause a suppression at low relative energies. The net result may accidentally be close to the conventional first-order E1 calculation, but there are differences which cannot be ignored if accuracies of 10% or better are needed

  2. Iodine tablets - many benefits and few disadvantages

    International Nuclear Information System (INIS)

    Paile, W.

    1996-01-01

    The number of thyroid cancers among children has increased steeply around Chernobyl after the nuclear catastrophe. An iodine tablet taken at the right time would have protected the thyroid from the effects of radioiodine. Nuclear fallout may contain large amounts of radioactive iodine. If this enters the body, either through inhalation or ingestion, most of it ends up in the thyroid. As a result, the thyroid may be exposed to a considerable radiation dose. High doses endanger the functioning of the thyroid, and even smaller doses may cause benign or malignant tumours in the thyroid. Sensitivity of the thyroid to radiation depends largely on the person's age. The younger the child, the higher the risk. Adults probably have a low risk. It has not been shown that people over 40 years of age would have any risk of contracting radiation-induced thyroid cancer. Iodine tablets are particularly important for children. Iodine has fewer side effects than had been thought previously. At least for children, the risk of side effects caused by one dose of iodine is so small that it can be ignored when considering whether iodine should be given in a fallout situation. The risk increases with age. It must unconditionally be left for the authorities to decide who should be given iodine tablets and when. (orig.)

  3. Active molecular iodine photochemistry in the Arctic.

    Science.gov (United States)

    Raso, Angela R W; Custard, Kyle D; May, Nathaniel W; Tanner, David; Newburn, Matt K; Walker, Lawrence; Moore, Ronald J; Huey, L G; Alexander, Liz; Shepson, Paul B; Pratt, Kerri A

    2017-09-19

    During springtime, the Arctic atmospheric boundary layer undergoes frequent rapid depletions in ozone and gaseous elemental mercury due to reactions with halogen atoms, influencing atmospheric composition and pollutant fate. Although bromine chemistry has been shown to initiate ozone depletion events, and it has long been hypothesized that iodine chemistry may contribute, no previous measurements of molecular iodine (I 2 ) have been reported in the Arctic. Iodine chemistry also contributes to atmospheric new particle formation and therefore cloud properties and radiative forcing. Here we present Arctic atmospheric I 2 and snowpack iodide (I - ) measurements, which were conducted near Utqiaġvik, AK, in February 2014. Using chemical ionization mass spectrometry, I 2 was observed in the atmosphere at mole ratios of 0.3-1.0 ppt, and in the snowpack interstitial air at mole ratios up to 22 ppt under natural sunlit conditions and up to 35 ppt when the snowpack surface was artificially irradiated, suggesting a photochemical production mechanism. Further, snow meltwater I - measurements showed enrichments of up to ∼1,900 times above the seawater ratio of I - /Na + , consistent with iodine activation and recycling. Modeling shows that observed I 2 levels are able to significantly increase ozone depletion rates, while also producing iodine monoxide (IO) at levels recently observed in the Arctic. These results emphasize the significance of iodine chemistry and the role of snowpack photochemistry in Arctic atmospheric composition, and imply that I 2 is likely a dominant source of iodine atoms in the Arctic.

  4. Hydrogen dissociation on metal surfaces

    OpenAIRE

    Wijzenbroek, M.

    2016-01-01

    Dissociative chemisorption is an important reaction step in many catalytic reactions. An example of such a reaction is the Haber-Bosch process, which is used commercially to produce ammonia, an important starting material in the production of fertilisers. In theoretical descriptions of such chemical processes often approximations need to be made in order to keep the computational cost feasible, such as fixing the surface atoms in place, rather than allowing them to vibrate. In this work, seve...

  5. Diffraction dissociation and elastic scattering

    International Nuclear Information System (INIS)

    Verebryusov, V.S.; Ponomarev, L.A.; Smorodinskaya, N.Ya.

    1987-01-01

    In the framework of Regge scheme with supercritical pomeron a model is suggested for the NN-scattering amplitude which takes into account the contribution introduced to the intermediate state by diffraction dissociation (DD) processes. The DD amplitude is written in terms of the Deck model which has been previously applied to describing the main DD features. The calculated NN cross sections are compared with those obtained experimentally. Theoretical predictions for higher energy are presented

  6. Dissociative Photoionization of Diethyl Ether.

    Science.gov (United States)

    Voronova, Krisztina; Mozaffari Easter, Chrissa M; Covert, Kyle J; Bodi, Andras; Hemberger, Patrick; Sztáray, Bálint

    2015-10-29

    The dissociative photoionization of internal energy selected diethyl ether ions was investigated by imaging photoelectron photoion coincidence spectroscopy. In a large, 5 eV energy range Et2O(+) cations decay by two parallel and three sequential dissociative photoionization channels, which can be modeled well using statistical theory. The 0 K appearance energies of the CH3CHOCH2CH3(+) (H-loss, m/z = 73) and CH3CH2O═CH2(+) (methyl-loss, m/z = 59) fragment ions were determined to be 10.419 ± 0.015 and 10.484 ± 0.008 eV, respectively. The reemergence of the hydrogen-loss ion above 11 eV is attributed to transition-state (TS) switching, in which the second, outer TS is rate-determining at high internal energies. At 11.81 ± 0.05 eV, a secondary fragment of the CH3CHOCH2CH3(+) (m/z = 73) ion, protonated acetaldehyde, CH3CH═OH(+) (m/z = 45) appears. On the basis of the known thermochemical onset of this fragment, a reverse barrier of 325 meV was found. Two more sequential dissociation reactions were examined, namely, ethylene and formaldehyde losses from the methyl-loss daughter ion. The 0 K appearance energies of 11.85 ± 0.07 and 12.20 ± 0.08 eV, respectively, indicate no reverse barrier in these processes. The statistical model of the dissociative photoionization can also be used to predict the fractional ion abundances in threshold photoionization at large temperatures, which could be of use in, for example, combustion diagnostics.

  7. Autonoesis and dissociative identity disorder.

    Science.gov (United States)

    Morton, John

    2018-01-01

    Dissociative identity disorder is characterised by the presence in one individual of two or more alternative personality states (alters). For such individuals, the memory representation of a particular event can have full episodic, autonoetic status for one alter, while having the status of knowledge or even being inaccessible to a second alter. This phenomenon appears to create difficulties for a purely representational theory and is presented to Mahr & Csibra (M&C) for their consideration.

  8. Iodine nutrition and risk of thyroid irradiation from nuclear accidents

    International Nuclear Information System (INIS)

    Delange, F.

    1990-01-01

    The objectives of this paper are to discuss the following aspects of physiopathology of iodine nutrition related to thyroid irradiation by nuclear accidents: (1) The cycle of iodine in nature, the dietary sources of iodine and the recommended dietary allowances for iodine. (2) The anomalies of thyroid metabolism induced by iodine deficiency. The caricatural situation as seen in endemic goitre will be used as mode. (3) The specific paediatric aspects of adaptation to iodine deficiency. (4) The present status of iodine nutrition in Europe. (author)

  9. Present status of iodine research at IPSN

    Energy Technology Data Exchange (ETDEWEB)

    Bardelay, J [IPSN/DPEA/SEAC (France)

    1996-12-01

    Since several years, IPSN has conducted an effort in order to evaluate the release of radioactive iodine in case of hypothetical severe accident in a realistic manner. This source-term evaluation is performed with IODE code which is a module of the EXCADRE system of codes. This code is validated against: -analytical experiments: in these experiments, IPSN studies radiolytic effects and chemical processes in the sump, organic formation, mass transfer, effect of spray (CARAIDAS experiment), - the CAIMAN semi global experiment; this experiment will allow to study the phenomena linked to iodine behavior under representative containment geometry in the presence of painted surfaces and global irradiation, - the PHEBUS FP program. The paper consists to describe succinctly the current status of IODE and the various experiments for its validation. In case of hypothetical severe accident iodine can induce important perturbations of human organism. The effects are principally radiological, in particular on the thyroid. At short term, radioactive iodine is the most important contributor for the sanitary risk. It represents 55% of effective dose and 92% of thyroid dose at 10 km in case of controlled rejects with current assumptions. This is the reason why it must be actively studied. In France, the safety evaluations are performed with mechanistic codes or lumped parameter codes like EXCADRE which contains a module devoted to iodine studies: IODINE. The objective of the French experimental program on iodine is to understand and quantify important phenomena in order to put kinetic parameters in IODE module. The experiments can be classified in analytical experiments, the semi-global experiment CAIMAN which takes into account different phenomena studied in analytical experiments and the global experiment PHEBUS PF, not only devoted to iodine behavior study. In the following text we will present the needs of IODINE code and these different experiments. (author).

  10. Present status of iodine research at IPSN

    International Nuclear Information System (INIS)

    Bardelay, J.

    1996-01-01

    Since several years, IPSN has conducted an effort in order to evaluate the release of radioactive iodine in case of hypothetical severe accident in a realistic manner. This source-term evaluation is performed with IODE code which is a module of the EXCADRE system of codes. This code is validated against: -analytical experiments: in these experiments, IPSN studies radiolytic effects and chemical processes in the sump, organic formation, mass transfer, effect of spray (CARAIDAS experiment), - the CAIMAN semi global experiment; this experiment will allow to study the phenomena linked to iodine behavior under representative containment geometry in the presence of painted surfaces and global irradiation, - the PHEBUS FP program. The paper consists to describe succinctly the current status of IODE and the various experiments for its validation. In case of hypothetical severe accident iodine can induce important perturbations of human organism. The effects are principally radiological, in particular on the thyroid. At short term, radioactive iodine is the most important contributor for the sanitary risk. It represents 55% of effective dose and 92% of thyroid dose at 10 km in case of controlled rejects with current assumptions. This is the reason why it must be actively studied. In France, the safety evaluations are performed with mechanistic codes or lumped parameter codes like EXCADRE which contains a module devoted to iodine studies: IODINE. The objective of the French experimental program on iodine is to understand and quantify important phenomena in order to put kinetic parameters in IODE module. The experiments can be classified in analytical experiments, the semi-global experiment CAIMAN which takes into account different phenomena studied in analytical experiments and the global experiment PHEBUS PF, not only devoted to iodine behavior study. In the following text we will present the needs of IODINE code and these different experiments. (author)

  11. [Clinical Handling of Patients with Dissociative Disorders].

    Science.gov (United States)

    Okano, Kenichiro

    2015-01-01

    This paper discusses the way informed psychiatrists are expected to handle dissociative patients in clinical situations, with a specific focus on dissociative identity disorders and dissociative fugue. On the initial interview with dissociative patients, information on their history of trauma and any nascent dissociative symptoms in their childhood should be carefully obtained. Their level of stress in their current life should also be assessed in order to understand their symptomatology, as well as to predict their future clinical course. A psychoeducational approach is crucial; it might be helpful to give information on dissociative disorder to these patients as well as their family members in order to promote their adherence to treatment. Regarding the symptomatology of dissociative disorders, detailed symptoms and the general clinical course are presented. It was stressed that dissociative identity disorder and dissociative fugue, the most high-profile dissociative disorders, are essentially different in their etiology and clinical presentation. Dissociative disorders are often confused with and misdiagnosed as psychotic disorders, such as schizophrenia. Other conditions considered in terms of the differential diagnosis include borderline personality disorder as well as temporal lobe epilepsy. Lastly, the therapeutic approach to dissociative identity disorder is discussed. Each dissociative identity should be understood as potentially representing some traumatically stressful event in the past. The therapist should be careful not to excessively promote the creation or elaboration of any dissociative identities. Three stages are proposed in the individual psychotherapeutic process. In the initial stage, a secure environment and stabilization of symptoms should be sought. The second stage consists of aiding the "host" personality to make use of other more adaptive coping skills in their life. The third stage involves coaching as well as continuous awareness of

  12. Consensus statement on iodine deficiency disorders in Hong Kong.

    Science.gov (United States)

    But, Betty; Chan, C W; Chan, Fredriech; Chan, K W; Cheng, Anna W F; Cheung, Patrick; Choi, K L; Chow, C B; Chow, Francis C C; Eastman, Creswell; Fok, T F; Fung, L M; Gomes, Cynthia; Huen, K F; Ip, T P; Kung, Annie W C; Lam, Karen S L; Lam, Y Y; Lao, Terence; Lee, C Y; Lee, K F; Leung, Jenny; Leung, N K; Li, Dominic; Li, June; Lo, K W; Lo, Louis; Ng, K L; Siu, S C; Tam, Sidney; Tan, Kathryn C B; Tiu, S C; Tse, H Y; Tse, Winnie; Wong, Gary; Wong, Shell; Wong, William; Yeung, Vincent T F; Young, Rosie; Yu, C M; Yu, Richard

    2003-12-01

    This article reviews the available data on the study of iodine deficiency disorders in Hong Kong and to discuss the approach towards preventing such disorders in Hong Kong. The importance of iodine and iodine deficiency disorders is described, and the available data on the dietary iodine intake and urinary iodine concentration in different populations of Hong Kong are summarised and discussed. Dietary iodine insufficiency among pregnant women in Hong Kong is associated with maternal goitrogenesis and hypothyroxinaemia as well as neonatal hypothyroidism. Borderline iodine deficiency exists in the expectant mothers in Hong Kong. Women of reproductive age, and pregnant and lactating women should be made aware and educated to have an adequate iodine intake, such as iodised salt, as an interim measure. A steering group involving all stakeholders should be formed to advise on the strategy of ensuring adequate iodine intake, including universal iodisation of salt in Hong Kong. Continuous surveillance of iodine status in the Hong Kong population is necessary.

  13. Study on iodine levels in thyroids of iodine-supplemented rats by epithermal neutron activation analysis

    International Nuclear Information System (INIS)

    Wang Xuefei; Zhang Fang; Xu Qing; Liu Nianqing; Chai Zhifang; Zhao Xueqin; Zuo Aijun

    2003-01-01

    The second generation female Wistar rats that have been treated with iodine-deficient food, after their delivery, are divided into three groups i.e. excessive-iodine (EI), adequate-iodine (AI) and iodine-deficient (ID) according to the KIO 3 concentration in the drinking water (3.0, 0.4, 0 mg/L). In addition, the normal rats with low iodine food and 0.4 mg/L KIO 3 water are used as the control group (C). The iodine content in thyroid and the serum thyroid hormone levels of the third generation rats are measured by means of epithermal neutron activation analysis (ENAA), and the method of enzyme-linked immunosorbent assay (ELISA), respectively. The results indicate that the total thyroxine (TT 4 ) and the free thyroxine (FT 4 ) of the EI, compared with those of the controls, are significantly decreased (p 3 ) evidently increased (p 4 , FT 4 and goiter

  14. Effect of chronic douching with polyvinylpyrrolidone-iodine on iodine absorption and thyroid function

    International Nuclear Information System (INIS)

    Safran, M.; Braverman, L.E.

    1982-01-01

    Daily vaginal douching with polyvinylpyrrolidone-iodine in 12 euthyroid volunteers for 14 days resulted in a significant increase in serum total iodine concentration and urine iodine excretion. The increase in serum total iodine was associated with a marked decrease in 24-hour 123 I uptake by the thyroid and a small but significant increase in serum thyrotropin (TSH) concentration. However, values for serum TSH never rose above the normal range. No significant changes in serum thyroxine (T4), free T4 index (FTI), or triiodothyronine concentrations were observed, although serum T4 and FTI did decrease slightly during treatment. The findings suggest that iodine is absorbed across the vaginal mucosa and that the subsequent increase in serum total iodine does induce subtle increases in serum TSH concentration. There was no evidence, however, of overt hypothyroidism in these euthyroid women

  15. Modeling an Iodine Hall Thruster Plume in the Iodine Satellite (ISAT)

    Science.gov (United States)

    Choi, Maria

    2016-01-01

    An iodine-operated 200-W Hall thruster plume has been simulated using a hybrid-PIC model to predict the spacecraft surface-plume interaction for spacecraft integration purposes. For validation of the model, the plasma potential, electron temperature, ion current flux, and ion number density of xenon propellant were compared with available measurement data at the nominal operating condition. To simulate iodine plasma, various collision cross sections were found and used in the model. While time-varying atomic iodine species (i.e., I, I+, I2+) information is provided by HPHall simulation at the discharge channel exit, the molecular iodine species (i.e., I2, I2+) are introduced as Maxwellian particles at the channel exit. Simulation results show that xenon and iodine plasma plumes appear to be very similar under the assumptions of the model. Assuming a sticking coefficient of unity, iodine deposition rate is estimated.

  16. Iodine in drinking water varies by more than 100-fold in Denmark. Importance for iodine content of infant formulas

    DEFF Research Database (Denmark)

    Pedersen, K M; Laurberg, P; Nøhr, S

    1999-01-01

    The iodine intake level of the population is of major importance for the occurrence of thyroid disorders in an area. The aim of the present study was to evaluate the importance of drinking water iodine content for the known regional differences in iodine intake in Denmark and for the iodine content...

  17. Iodine-123 program at the TRIUMF laboratory

    International Nuclear Information System (INIS)

    Vincent, J.S.

    1985-01-01

    A research program for the production and utilization of iodine-123 is described. From 1979 to 1982 the spallation of elemental cesium by 500-MeV protons was used to provide 100 mCi/hr at the end of bombardment (EOB). Contaminants were 3% iodine-125 and 0.15% tellurium-121 at EOB + 36 hr. The material from weekly runs was used by remote clinics in Canada for evaluation as a radiochemical and for labeling studies. A new facility at TRIUMF will be operational in 1983 to produce iodine-123 by the (p,5n) reaction

  18. Autoradiography for iodine-125 seeds

    International Nuclear Information System (INIS)

    Alberti, W.; Divoux, S.; Pothmann, B.; Tabor, P.; Hermann, K.P.; Harder, D.

    1993-01-01

    To study the interior design of model 6702 and 6711 iodine-125 seeds, contact autoradiographs were performed using mammography film. Improved resolution was obtained using a pin-hole camera with a hole of 0.1 mm x 0.1 mm. With these techniques, qualitative determination of the relative activity distribution within each seed was possible. The number of the activated resin spheres and the positions of the centers of these spheres can be exactly determined. A model calculation shows that variations in the arrangement of the activated spheres within a seed have a moderate influence on the dose distribution at source distances below 10 mm. Knowing the exact source configuration may be useful when comparing dose calculations with measured data for model 6702 125 I seeds which are currently employed in ophthalmic plaque and implant therapy of other tumors. 16 refs., 5 figs., 2 tabs

  19. Iodine-123 in Western Europe

    International Nuclear Information System (INIS)

    Qaim, S.M.; Stoecklin, G.; Weinreich, R.

    1976-08-01

    The major object of this panel was to obtain information on the state of art of Iodine-123 production in Western Europe. Technical, medical and organizational problems were discussed extensively during the one-day meeting and a stimulating exchange of information between the various 123 I-producers and users has been initiated. Some specific examples of medical application were also included in order to get a feeling of the degree of acceptance by the medical community and the demand for this isotope. The meeting clearly demonstrated the great demand for this isotope but it also showed that the present rate of production is well below the demand. In order to fill this gap, not only further technical development is needed but also the organizational question of distribution has to be solved, perhaps within a network of collaborating cyclotrons, a task which is considerably more difficult in Western Europe than in the USA. (orig./HP) [de

  20. Studies in iodine metabolism. Progress report, April 1975-- March 1976

    International Nuclear Information System (INIS)

    Van Middlesworth, L.

    1976-01-01

    Investigations during the past twelve months have included the following subjects: factors which influence release of radioiodine from thyroid glands; contamination of commercially available low-iodine diets; effects of hypoxia on release of iodine from thyroid glands of rats and mice; development of practical tests for available iodine in low-iodine diets; reproduction and abnormal thyroglobulin of rats maintained on low-iodine diets; observations on radioactivity in animal thyroids; collaboration with other laboratories regarding radium in bovine thyroids

  1. A model to secure a stable iodine concentration in milk

    Directory of Open Access Journals (Sweden)

    Gisken Trøan

    2015-12-01

    Full Text Available Background: Dairy products account for approximately 60% of the iodine intake in the Norwegian population. The iodine concentration in cow's milk varies considerably, depending on feeding practices, season, and amount of iodine and rapeseed products in cow fodder. The variation in iodine in milk affects the risk of iodine deficiency or excess in the population. Objective: The first goal of this study was to develop a model to predict the iodine concentration in milk based on the concentration of iodine and rapeseed or glucosinolate in feed, as a tool to securing stable iodine concentration in milk. A second aim was to estimate the impact of different iodine levels in milk on iodine nutrition in the Norwegian population. Design: Two models were developed on the basis of results from eight published and two unpublished studies from the past 20 years. The models were based on different iodine concentrations in the fodder combined with either glucosinolate (Model 1 or rapeseed cake/meal (Model 2. To illustrate the impact of different iodine concentrations in milk on iodine intake, we simulated the iodine contribution from dairy products in different population groups based on food intake data in the most recent dietary surveys in Norway. Results: The models developed could predict iodine concentration in milk. Cross-validation showed good fit and confirmed the explanatory power of the models. Our calculations showed that dairy products with current iodine level in milk (200 µg/kg cover 68, 49, 108 and 56% of the daily iodine requirements for men, women, 2-year-old children, and pregnant women, respectively. Conclusions: Securing a stable level of iodine in milk by adjusting iodine concentration in different cow feeds is thus important for preventing excess intake in small children and iodine deficiency in pregnant and non-pregnant women.

  2. Quantitative method for determination of body inorganic iodine

    International Nuclear Information System (INIS)

    Filatov, A.A.; Tatsievskij, V.A.

    1991-01-01

    An original method of quantitation of body inorganic iodine, based upon a simultaneous administration of a known dose of stable and radioactive iodine with subsequent radiometry of the thyroid was proposed. The calculation is based upon the principle of the dilution of radiactive iodine in human inorganic iodine space. The method permits quantitation of the amount of inorganic iodine with regard to individual features of inorganic space. The method is characterized by simplicity and is not invasive for a patient

  3. Method of removing iodine and compounds thereof from gaseous effluents

    International Nuclear Information System (INIS)

    Keener, R.L.; Kittle, P.A.

    1976-01-01

    Anion exchange resins including an acrylic backbone formed by the suspension polymerization of a mixture of an acrylic and a crosslinking monomer are useful in the removal of iodine and iodine compounds from gaseous effluents. Removal of radioactive iodine contaminants, particularly alkyl iodine compounds or hydrogen iodine, under extreme conditions, namely temperatures up to 180 0 C and humidities up to 100 percent, from effluents resulting from a major nuclear accident could probably be adsorbed by these resins described herein

  4. Analysis of iodine content in seaweed by GC-ECD and estimation of iodine intake

    Directory of Open Access Journals (Sweden)

    Tai Sheng Yeh

    2014-06-01

    Full Text Available Edible seaweed products have been consumed in many Asian countries. Edible seaweeds accumulate iodine from seawater, and are therefore a good dietary source of iodine. An adequate consumption of seaweed can eliminate iodine deficiency disorders, but excessive iodine intake is not good for health. The recommended dietary reference intake of 0.15 mg/d and 0.14 mg/d for iodine has been established in the United States and Taiwan, respectively. In this study, 30 samples of seaweed were surveyed for iodine content. The samples included 10 nori (Porphyra, 10 wakame (Undaria, and 10 kombu (Laminaria products. The iodine in seaweed was derivatized with 3-pentanone and detected by gas chromatography-electron capture detector (GC-ECD. The method detection limit was 0.5 mg/kg. The iodine content surveyed for nori was 29.3–45.8 mg/kg, for wakame 93.9–185.1 mg/kg, and for kombu 241–4921 mg/kg. Kombu has the highest average iodine content 2523.5 mg/kg, followed by wakame (139.7 mg/kg and nori (36.9 mg/kg. The GC-ECD method developed in this study is a low-cost alternative to inductively coupled plasma-optical emission spectroscopy for iodine detection in seaweeds. The iodine intake from seaweed in the current survey was calculated and compared with the iodine dietary reference intake of Taiwan. The risk and benefit of seaweed consumption is also discussed.

  5. Iodine binding to humic acid.

    Science.gov (United States)

    Bowley, H E; Young, S D; Ander, E L; Crout, N M J; Watts, M J; Bailey, E H

    2016-08-01

    The rate of reactions between humic acid (HA) and iodide (I(-)) and iodate (IO3(-)) have been investigated in suspensions spiked with (129)I at concentrations of 22, 44 and 88 μg L(-1) and stored at 10 °C. Changes in the speciation of (129)I(-), (129)IO3(-) and mixed ((129)I(-) + (129)IO3(-)) spikes were monitored over 77 days using liquid chromatography inductively coupled plasma mass spectrometry (LC-ICP-MS). In suspensions spiked with (129)I(-) 25% of the added I(-) was transformed into organic iodine (Org-(129)I) within 77 days and there was no evidence of (129)IO3(-) formation. By contrast, rapid loss of (129)IO3(-) and increase in both (129)I(-) and Org-(129)I was observed in (129)IO3(-)-spiked suspensions. However, the rate of Org-(129)I production was greater in mixed systems compared to (129)IO3(-)-spiked suspensions with the same total (129)I concentration, possibly indicating IO3(-)I(-) redox coupling. Size exclusion chromatography (SEC) demonstrated that Org-(129)I was present in both high and low molecular weight fractions of the HA although a slight preference to bond with the lower molecular weight fractions was observed indicating that, after 77 days, the spiked isotope had not fully mixed with the native (127)I pool. Iodine transformations were modelled using first order rate equations and fitted rate coefficients determined. However, extrapolation of the model to 250 days indicated that a pseudo-steady state would be attained after ∼200 days but that the proportion of (129)I incorporated into HA was less than that of (127)I indicating the presence of a recalcitrant pool of (127)I that was unavailable for isotopic mixing. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Study on Shale Adsorption Equation Based on Monolayer Adsorption, Multilayer Adsorption, and Capillary Condensation

    Directory of Open Access Journals (Sweden)

    Qing Chen

    2017-01-01

    Full Text Available Shale gas is an effective gas resource all over the world. The evaluation of pore structure plays a critical role in exploring shale gas efficiently. Nitrogen adsorption experiment is one of the significant approaches to analyze pore size structure of shale. Shale is extremely heterogeneous due to component diversity and structure complexity. Therefore, adsorption isotherms for homogeneous adsorbents and empirical isotherms may not apply to shale. The shape of adsorption-desorption curve indicates that nitrogen adsorption on shale includes monolayer adsorption, multilayer adsorption, and capillary condensation. Usually, Langmuir isotherm is a monolayer adsorption model for ideal interfaces; BET (Brunauer, Emmett, Teller adsorption isotherm is a multilayer adsorption model based on specific assumptions; Freundlich isotherm is an empirical equation widely applied in liquid phase adsorption. In this study, a new nitrogen adsorption isotherm is applied to simultaneously depict monolayer adsorption, multilayer adsorption, and capillary condensation, which provides more real and accurate representation of nitrogen adsorption on shale. In addition, parameters are discussed in relation to heat of adsorption which is relevant to the shape of the adsorption isotherm curve. The curve fitting results indicate that our new nitrogen adsorption isotherm can appropriately describe the whole process of nitrogen adsorption on shale.

  7. The retention of iodine by iodine filters in nuclear power plants in the case of fire

    International Nuclear Information System (INIS)

    Giraud, V.

    1985-01-01

    Due to the liberation of considerable amounts of gaseous combustion products, fires in nuclear power plants may lead to a deterioration in the retention of radioiodine by iodine filters. The combustion products of the burnable materials, i.e., insulations, lubricants and paints, vary considerably with the development of the fire. Combustion product analyses of these materials have been performed only to a limited extent. The reaction of iodine with combustion products as well as the retention of the resulting iodine reaction products by sorbents have not yet been investigated. The reduction in the removal efficiencies of iodine sorbents due to the presence of combustion products is unknown. (orig.) [de

  8. Iodine deficiency in pregnancy in Denmark. Regional variations and frequency of individual iodine supplementation

    DEFF Research Database (Denmark)

    Nøhr, S B; Laurberg, P; Børlum, K G

    1993-01-01

    micrograms/g creatinine). These values are far below internationally recommended levels. The consequences remain to be evaluated and no firm recommendations can be given. It seems reasonable, however, to recommend a high intake of food containing iodine (e.g. milk products) during pregnancy and lactation...... containing vitamin/mineral tablets. Approximately one third of the women had received tablets containing iodine. In women who had not received iodine supplementation urinary iodine was low with a median value of 39.7 micrograms/g creatinine (Aalborg 28, Randers 33, Ringkøbing 34, Arhus 43 and Copenhagen 62...

  9. Iodine deficiency in pregnancy in Denmark. Regional variations and frequency of individual iodine supplementation

    DEFF Research Database (Denmark)

    Nøhr, S B; Laurberg, Peter; Børlum, K G

    1993-01-01

    Iodine requirements are increased during pregnancy and lactation and adequate iodine intake is important for normal brain development of the fetus/newborn child. The aim of the present study was to evaluate the extent to which this increase in iodine requirement is met in pregnant women living...... micrograms/g creatinine). These values are far below internationally recommended levels. The consequences remain to be evaluated and no firm recommendations can be given. It seems reasonable, however, to recommend a high intake of food containing iodine (e.g. milk products) during pregnancy and lactation...

  10. Iodination and stability of somatostatin analogues: comparison of iodination techniques. A practical overview.

    Science.gov (United States)

    de Blois, Erik; Chan, Ho Sze; Breeman, Wouter A P

    2012-01-01

    For iodination ((125/127)I) of tyrosine-containing peptides, chloramin-T, Pre-Coated Iodo-Gen(®) tubes and Iodo-Beads(®) (Pierce) are commonly used for in vitro radioligand investigations and there have been reliant vendors hereof for decades. However, commercial availability of these radio-iodinated peptides is decreasing. For continuation of our research in this field we investigated and optimized (radio-)iodination of somatostatin analogues. In literature, radioiodination using here described somatostatin analogues and iodination techniques are described separately. Here we present an overview, including High Performance Liquid Chromatography (HPLC) separation and characterisation by mass spectrometry, to obtain mono- and di-iodinated analogues. Reaction kinetics of (125/127)I iodinated somatostatin analogues were investigated as function of reaction time and concentration of reactants, including somatostatin analogues, iodine and oxidizing agent. To our knowledge, for the here described somatostatin analogues, no (127)I iodination and optimization are described. (Radio-)iodinated somatostatin analogues could be preserved with a >90% radiochemical purity for 1 month after reversed phase HPLC-purification.

  11. Suboptimal Iodine Concentration in Breastmilk and Inadequate Iodine Intake among Lactating Women in Norway.

    Science.gov (United States)

    Henjum, Sigrun; Lilleengen, Anne Marie; Aakre, Inger; Dudareva, Anna; Gjengedal, Elin Lovise Folven; Meltzer, Helle Margrete; Brantsæter, Anne Lise

    2017-06-22

    Breastfed infants depend on sufficient maternal iodine intake for optimal growth and neurological development. Despite this, few studies have assessed iodine concentrations in human milk and there is currently no published data on iodine status among lactating women in Norway. The aim of this study was to assess iodine concentrations in breast milk (BMIC) in lactating women and estimate iodine intake. Five Mother and Child Health Centres in Oslo were randomly selected during 2016, and 175 lactating women between 2nd and 28th weeks postpartum participated. Each of the women provided four breastmilk samples which were pooled and analysed for iodine concentrations. Participants also provided information on iodine intake from food and supplements covering the last 24 h and the habitual iodine intake (food frequency questionnaire). The median (p25, p75 percentiles) BMIC was 68 (45, 98) µg/L and 76% had BMIC food (p25, p75) was 121 (82, 162) µg/day and the total intake (food and supplements) was 134 (95, 222) µg/day. The majority of lactating women had suboptimal BMIC and inadequate intake of iodine from food and supplements.

  12. Iodine and creatinine testing in urine dried on filter paper

    Energy Technology Data Exchange (ETDEWEB)

    Zava, Theodore T., E-mail: ttzava@zrtlab.com [ZRT Laboratory, 8605 SW Creekside Place, Beaverton, OR 97008 (United States); Kapur, Sonia, E-mail: soniak@zrtlab.com [ZRT Laboratory, 8605 SW Creekside Place, Beaverton, OR 97008 (United States); Zava, David T., E-mail: dzava@zrtlab.com [ZRT Laboratory, 8605 SW Creekside Place, Beaverton, OR 97008 (United States)

    2013-02-18

    Highlights: ► Dried urine iodine and creatinine extract quantitatively correlates well with liquid urine. ► Filter paper strips can be easily shipped and stored. ► Urine iodine and creatinine are stable at ambient temperature when dried on filter paper. ► Dried urine iodine and creatinine are run using a 96-well format. -- Abstract: Iodine deficiency is a world-wide health problem. A simple, convenient, and inexpensive method to monitor urine iodine levels would have enormous benefit in determining an individual's recent iodine intake or in identifying populations at risk for iodine deficiency or excess. Current methods used to monitor iodine levels require collection of a large volume of urine and its transport to a testing laboratory, both of which are inconvenient and impractical in parts of the world lacking refrigerated storage and transportation. To circumvent these limitations we developed and validated methods to collect and measure iodine and creatinine in urine dried on filter paper strips. We tested liquid urine and liquid-extracted dried urine for iodine and creatinine in a 96-well format using Sandell–Kolthoff and Jaffe reactions, respectively. Our modified dried urine iodine and creatinine assays correlated well with established liquid urine methods (iodine: R{sup 2} = 0.9483; creatinine: R{sup 2} = 0.9782). Results demonstrate that the dried urine iodine and creatinine assays are ideal for testing the iodine status of individuals and for wide scale application in iodine screening programs.

  13. Development of Databases on Iodine in Foods and Dietary Supplements

    Science.gov (United States)

    Ershow, Abby G.; Skeaff, Sheila A.; Merkel, Joyce M.; Pehrsson, Pamela R.

    2018-01-01

    Iodine is an essential micronutrient required for normal growth and neurodevelopment; thus, an adequate intake of iodine is particularly important for pregnant and lactating women, and throughout childhood. Low levels of iodine in the soil and groundwater are common in many parts of the world, often leading to diets that are low in iodine. Widespread salt iodization has eradicated severe iodine deficiency, but mild-to-moderate deficiency is still prevalent even in many developed countries. To understand patterns of iodine intake and to develop strategies for improving intake, it is important to characterize all sources of dietary iodine, and national databases on the iodine content of major dietary contributors (including foods, beverages, water, salts, and supplements) provide a key information resource. This paper discusses the importance of well-constructed databases on the iodine content of foods, beverages, and dietary supplements; the availability of iodine databases worldwide; and factors related to variability in iodine content that should be considered when developing such databases. We also describe current efforts in iodine database development in the United States, the use of iodine composition data to develop food fortification policies in New Zealand, and how iodine content databases might be used when considering the iodine intake and status of individuals and populations. PMID:29342090

  14. Iodine and creatinine testing in urine dried on filter paper

    International Nuclear Information System (INIS)

    Zava, Theodore T.; Kapur, Sonia; Zava, David T.

    2013-01-01

    Highlights: ► Dried urine iodine and creatinine extract quantitatively correlates well with liquid urine. ► Filter paper strips can be easily shipped and stored. ► Urine iodine and creatinine are stable at ambient temperature when dried on filter paper. ► Dried urine iodine and creatinine are run using a 96-well format. -- Abstract: Iodine deficiency is a world-wide health problem. A simple, convenient, and inexpensive method to monitor urine iodine levels would have enormous benefit in determining an individual's recent iodine intake or in identifying populations at risk for iodine deficiency or excess. Current methods used to monitor iodine levels require collection of a large volume of urine and its transport to a testing laboratory, both of which are inconvenient and impractical in parts of the world lacking refrigerated storage and transportation. To circumvent these limitations we developed and validated methods to collect and measure iodine and creatinine in urine dried on filter paper strips. We tested liquid urine and liquid-extracted dried urine for iodine and creatinine in a 96-well format using Sandell–Kolthoff and Jaffe reactions, respectively. Our modified dried urine iodine and creatinine assays correlated well with established liquid urine methods (iodine: R 2 = 0.9483; creatinine: R 2 = 0.9782). Results demonstrate that the dried urine iodine and creatinine assays are ideal for testing the iodine status of individuals and for wide scale application in iodine screening programs

  15. Method for removing radioactive iodine and radioactive organic iodides from effluent gases

    International Nuclear Information System (INIS)

    1975-01-01

    A method and composition for removing radioactive and organic iodides from an 131 I-containing off-gas stream is provided. The composition for removal by adsorption is a ceramic material with a surface area of from about 5 m 2 /g to about 250 m 2 /g impregnated with a metallic salt. The method for removing the iodine or iodide is accomplished by passing the off-gas stream over the ceramic material impregnated with the metallic salt. It finds special application in air filters for nuclear power plants

  16. Air filtration plants of wall-type for separation of fission iodine in nuclear reactors

    International Nuclear Information System (INIS)

    Stiehl, H.H.; Neumann, M.; Sinhuber, D.

    1976-01-01

    The increasing density of nuclear power stations and increased safety requirements will lead in future to higher flow rates and longer residence times in the adsorption filter layer of the iodine sorption filter plants of nuclear power stations. The safety requirements in the Federal Republic of Germany have been complied with so far in the conventional way by means of duct-type filter constructions. For the higher flow rates and longer residence times necessary in future, we propose a filter construction of wall-type, which complies with the safety regulations of the Federal Republic of Germany. The economic and technical advantages are discussed

  17. adsorption, eosin, humic, peat

    OpenAIRE

    anshar, andi muhammad

    2015-01-01

    Eosin is one of the dyes commonly used in the industry and has the potential to cause pollution of the water environment. The Eosin pollution treatment methods used in this study was the adsorption method using humin fraction obtained from the peat land comes from Kalimantan. From the research data showed that the adsorption of eosin in humin result of washing with HCl / HF optimum at pH 4 and a contact time of 60 minutes with the adsorption-order rate was 8,4 x 10-3 min-1

  18. Acidic gases (CO{sub 2}, NO{sub 2} and SO{sub 2}) capture and dissociation on metal decorated phosphorene

    Energy Technology Data Exchange (ETDEWEB)

    Kuang, Anlong, E-mail: alkuang@swu.edu.cn [School of Physical Science and Technology, Southwest University, Chongqing 400715 (China); Kuang, Minquan; Yuan, Hongkuan; Wang, Guangzhao; Chen, Hong [School of Physical Science and Technology, Southwest University, Chongqing 400715 (China); Yang, Xiaolan [School of Materials Science and Engineering, Beihang University, Beijing 100191 (China)

    2017-07-15

    Highlights: • The light metal decorated phosphorene sheets are very effective for capture of CO{sub 2}, NO{sub 2} and SO{sub 2} because of large adsorption energies. • The adsorption energy is obviously dependent on the amount of electrons transferred between acidic gases and metal decorated phosphorene. • Pt-decorated phosphorene can effectively catalyze the dissociation of acidic gas. - Abstract: Density functional theory is employed to investigate the adsorption and dissociation of several acidic gases (CO{sub 2}, NO{sub 2} and SO{sub 2}) on metal (Li, Al, Ni and Pt) decorated phosphorene. The results show that light metal (Li, Al) decorated phosphorene exhibits a strong adsorption of acidic gases, i.e., the adsorption energy of CO{sub 2} on Li decorated phosphorene is 0.376 eV which is the largest in all adsorption of CO{sub 2} on metal decorated phosphorene and Al decorated phosphorene is most effective for capture of NO{sub 2} and SO{sub 2} due to large adsorption energies of 3.951 and 3.608 eV, respectively. Moreover, Li and Al light metals have stronger economic effectiveness and more friendly environment compared with the transition metals, the strong adsorption ability of acidic gases and low price suggest that Li, Al decorated phosphorene may be useful and promising for collection and filtration of exhaust gases. The reaction energy barriers of acidic gases dissociated process on Pt decorated phosphorene are relatively low and the reaction processes are significantly exothermic, indicating that the dissociation process is favorable.

  19. Competitive Protein Adsorption - Multilayer Adsorption and Surface Induced Protein Aggregation

    DEFF Research Database (Denmark)

    Holmberg, Maria; Hou, Xiaolin

    2009-01-01

    In this study, competitive adsorption of albumin and IgG (immunoglobulin G) from human serum solutions and protein mixtures onto polymer surfaces is studied by means of radioactive labeling. By using two different radiolabels (125I and 131I), albumin and IgG adsorption to polymer surfaces...... is monitored simultaneously and the influence from the presence of other human serum proteins on albumin and IgG adsorption, as well as their mutual influence during adsorption processes, is investigated. Exploring protein adsorption by combining analysis of competitive adsorption from complex solutions...... of high concentration with investigation of single protein adsorption and interdependent adsorption between two specific proteins enables us to map protein adsorption sequences during competitive protein adsorption. Our study shows that proteins can adsorb in a multilayer fashion onto the polymer surfaces...

  20. A mathematical model for iodine kinetics

    International Nuclear Information System (INIS)

    Silva, E.A.T. da.

    1976-01-01

    A mathematical model for the iodine kinetics in thyroid is presented followed by its analytical solution. An eletroanalogical model is also developed for a simplified stage and another is proposed for the main case [pt

  1. Cement materials for cesium and iodine confinement

    International Nuclear Information System (INIS)

    Nicolas, G.; Lequeux, N.; Boch, P.; Prene, S.

    2001-01-01

    The following topics were dealt with: radioactive waste storage, cement materials reacting with radioactive cesium and iodine, chemical barrier formation against radioactive pollution, ceramization, long term stability, XRD, PIXE analysis

  2. Iodine behaviour in the SLOWPOKE nuclear reactor

    Energy Technology Data Exchange (ETDEWEB)

    Bekeris, P A; Evans, G J [Toronto Univ., ON (Canada). Dept. of Chemical Engineering and Applied Chemistry

    1994-12-31

    The purpose of this project is to measure and attempt to explain the presence and volatility of iodine isotopes present as fission products in the SLOWPOKE-2 reactor. Liquid sampling and extraction procedures developed indicated that approximately 40% of the reactor iodine is in the form of iodate (IO{sub 3}{sup -}), and 60% is in the form of iodide (I{sup -}). No appreciable amount in non-polar forms such as molecular iodine (I{sub 2}) or organic iodides (RI) were detected. This goes contrary to past expectations that all of the iodine in the liquid phase would be in the form of I{sup -}. In addition partition coefficients for I-131 were determined as 2-6x10{sup 6} at a neutral pH. Kr-88 is suspected as a possible interfering isotope in the measurement of I-131 in the liquid and gas phases. (author). 9 refs., 2 tabs., 2 figs.

  3. The adsorption of nitrogen oxides on crystalline ice

    Directory of Open Access Journals (Sweden)

    T. Bartels

    2002-01-01

    Full Text Available The partitioning of nitrogen oxides between ice and air is of importance to the ozone budget in the upper troposphere. In the present study, adsorption of nitrogen oxides on ice was investigated at atmospheric pressure using a chromatographic technique with radioactively labelled nitrogen oxides at low concentrations. The measured retentions solely depended on molecular adsorption and were not influenced by dimerisation, formation of encapsulated hydrates on the ice surface, dissociation of the acids, nor by migration into a quasi-liquid layer or grain boundaries. Based on the chromatographic retention and the model of thermo-chromatography, the standard adsorption enthalpy of -20 kJ mol-1 for NO, -22kJ mol-1 for NO2, -30kJ mol-1 for peroxyacetyl nitrate, -32kJ mol-1 for HON} and -44 kJ mol-1 for HNO3 was calculated. To perform those calculations within the model of thermo-chromatography, the standard adsorption entropy was calculated based on statistical thermodynamics. In this work, two different choices of standard states were applied, and consequently different values of the standard adsorption entropy, of either between -39 kJ mol-1 and -45kJ mol-1, or -164 kJ mol-1 and -169 kJ mol-1 for each nitrogen oxide were derived. The standard adsorption enthalpy was identical for both standard adsorption entropies and thus shown to be independent of the choice of standard state. A brief outlook on environmental implications of our findings indicates that adsorption on ice might be an important removal process of HNO3. In addition, it might be of some importance for HONO and peroxyacetyl nitrate and irrelevant for NO and NO2.

  4. Processes of H{sub 2} adsorption on Fe(1 1 0) surface: A density functional theory study

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Weiwei; Peng, Liang; Peng, Daoling [Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Gu, Feng Long, E-mail: gu@scnu.edu.cn [Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Liu, Jun [Material Design and Simulation Technology Co. Ltd., Room 1716, V-Faction, 10 Vanke, 2 Ring Road of North Section, Chengdu (China)

    2014-03-01

    Highlights: • The hydrogen coverages for H{sub 2} adsorption on Fe(1 1 0) surface ranging from 0.125 to 1.000 are prepared by using different surface supercells. • With the reduction of coverage, the average iron atomic energy is increased and the adsorption energy is decreased, leading to the system more stable; while coverage has little effect on the Fe(1 1 0) surface structure and the hydrogen adsorption process. • The most stable absorption site is found to be the on-top site. • DFT calculations show that it is a weak adsorption and the adsorption energy barriers under 4.4 kcal/mol. • The final state is H{sub 2} molecule dissociated into two hydrogen atoms interacting with surface iron atoms to form stable Fe-H bonds. - Abstract: Processes of H{sub 2} adsorption on Fe(1 1 0) surface have been studied by the density functional theory, properties such as surface structure, adsorption position, and adsorption energies are discussed as well. To investigate the atomic geometries and stability under different hydrogen coverages for this adsorption, the hydrogen coverages ranging from 0.125 to 1.000 are prepared by using different surface supercells. It is found that with the reduction of coverage, the average iron atomic energy and the adsorption energy are increased, leading to the system more stable; while coverage has little effect on the Fe(1 1 0) surface structure and the hydrogen adsorption process. The most stable absorption site is found to be the on-top site. Our calculations show that it is a weak adsorption and the adsorption energy barriers under 4.4 kcal/mol. The final state is H{sub 2} molecule dissociated into two hydrogen atoms and interacting with surface iron atoms to form stable Fe-H bonds.

  5. Study of iodine-iodate isotopic exchange reaction in neutral aqueous solutions by radiotracer technique

    International Nuclear Information System (INIS)

    Tripathi, R.; Ram, K.D.

    1993-01-01

    The isotopic exchange of iodine atoms in neutral aqueous solutions of iodate ions and iodine (in KI) is found to obey the rate law R = k [IO 3 - ] 0.4 [I 2 ] 1.2 at 175 o C. The addition of neutral ionic salts, e.g. KCl and KNO 3 , in the reaction mixture showed a slight catalytic effect on the exchange rate. Further, the kinetic salt effect indicated the involvement of at least one neutral species on the rate-determining step. The activation energy in neutral aqueous solutions of iodate ions and iodine is found to be 86 ± 3 kJ mol -1 , which decreases in the presence of KCl (79 ± 3 kJ mol -1 and KNO 3 (82 + 3 kJ mol -1 ). The activation parameters, viz. free energy of activation, enthalpy of activation and entropy of activation, were also calculated. Based on these results, an association-dissociation type of reaction mechanism is proposed for this exchange reaction in neutral aqueous medium, similar to that proposed earlier for iodide-iodate isotopic exchange reaction in neutral aqueous solutions, nitrate eutectic melts and iodide-iodate melts. (author)

  6. Water dissociation on Ni(100) and Ni(111): Effect of surface temperature on reactivity

    International Nuclear Information System (INIS)

    Seenivasan, H.; Tiwari, Ashwani K.

    2013-01-01

    Water adsorption and dissociation on Ni(100) and Ni(111) surfaces are studied using density functional theory calculations. Water adsorbs on top site on both the surfaces, while H and OH adsorb on four fold hollow and three fold hollow (fcc) sites on Ni(100) and Ni(111), respectively. Transition states (TS) on both surfaces are identified using climbing image-nudged elastic band method. It is found that the barrier to dissociation on Ni(100) surface is slightly lower than that on Ni(111) surface. Dissociation on both the surfaces is exothermic, while the exothermicity on Ni(100) is large. To study the effect of lattice motion on the energy barrier, TS calculations are performed for various values of Q (lattice atom coordinate along the surface normal) and the change in the barrier height and position is determined. Calculations show that the energy barrier to reaction decreases with increasing Q and increases with decreasing Q on both the surfaces. Dissociation probability values at different surface temperatures are computed using semi-classical approximation. Results show that the influence of surface temperature on dissociation probability on the Ni(100) is significantly larger compared to that of Ni(111). Moreover, on Ni(100), a dramatic shift in energy barrier to lower incident energy values is observed with increasing surface temperature, while the shift is smaller in the case of Ni(111)

  7. Controlling Chemical Reactions in Confined Environments: Water Dissociation in MOF-74

    Directory of Open Access Journals (Sweden)

    Erika M. A. Fuentes-Fernandez

    2018-02-01

    Full Text Available The confined porous environment of metal organic frameworks (MOFs is an attractive system for studying reaction mechanisms. Compared to flat oxide surfaces, MOFs have the key advantage that they exhibit a well-defined structure and present significantly fewer challenges in experimental characterization. As an example of an important reaction, we study here the dissociation of water—which plays a critical role in biology, chemistry, and materials science—in MOFs and show how the knowledge of the structure in this confined environment allows for an unprecedented level of understanding and control. In particular, combining in-situ infrared spectroscopy and first-principles calculations, we show that the water dissociation reaction can be selectively controlled inside Zn-MOF-74 by alcohol, through both chemical and physical interactions. Methanol is observed to speed up water dissociation by 25% to 100%, depending on the alcohol partial pressure. On the other hand, co-adsorption of isopropanol reduces the speed of the water reaction, due mostly to steric interactions. In addition, we also investigate the stability of the product state after the water dissociation has occurred and find that the presence of additional water significantly stabilizes the dissociated state. Our results show that precise control of reactions within nano-porous materials is possible, opening the way for advances in fields ranging from catalysis to electrochemistry and sensors.

  8. The determination of iodine 129 in thyroids

    International Nuclear Information System (INIS)

    Gros, Roger; Cappellini, Liliane; Goujon de Beauvivier, Michel; Jeanmaire, Lucien; Patti, Francois.

    1975-08-01

    Activation analysis was used for the determination of 129 I in thyroids. Iodine is first extracted from the thyroid and irradiated as lead iodate, thus giving enough sensitivity and making it possible to use common laboratory material. The results showed that the present activity levels in France are between 1 and 50 pCi per gram of iodine; the values found in Argentina are clearly lower [fr

  9. LWR severe accident simulation: Iodine behaviour in FPT2 experiment and advances on containment iodine chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Girault, N., E-mail: nathalie.girault@irsn.fr [Institut de Radioprotection et de Surete Nucleaire (IRSN), BP3 - 13115 St.-Paul-lez-Durance (France); Bosland, L. [Institut de Radioprotection et de Surete Nucleaire (IRSN), BP3 - 13115 St.-Paul-lez-Durance (France); Dickinson, S. [National Nuclear Laboratory, Harwell, Oxon OX11 0QT (United Kingdom); Funke, F. [AREVA NP Gmbh, PO Box 1109, 91001 Erlangen (Germany); Guentay, S. [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Herranz, L.E. [Centro des Investigaciones Energeticas, MedioAmbiantales y Tecnologicas, av. Complutense 2, 28040 Madrid (Spain); Powers, D. [Sandia National Laboratories, New Mexico, PO Box 5800, Albuquerque, NM 87185 (United States)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer Short term gaseous iodine fraction can be produced either in primary circuit or on containment condensing surfaces. Black-Right-Pointing-Pointer Gaseous radiolytic reactions convert volatile iodine into non-volatile iodine oxide particulates. Black-Right-Pointing-Pointer Alkaline and evaporating sump decrease the iodine volatility in containment. Black-Right-Pointing-Pointer Release of volatile iodine from containment surfaces explained the long term stationary residual gaseous iodine concentration. - Abstract: The Phebus Fission Product (FP) Program studies key phenomena of severe accidents in water-cooled nuclear reactors. In the framework of the Phebus program, five in-pile experiments have been performed that cover fuel rod degradation and behaviour of fission products released via the coolant circuit into the containment vessel. The focus of this paper is on iodine behaviour during the Phebus FPT2 test. FPT2 used a 33 GWd/t uranium dioxide fuel enriched to 4.5%, re-irradiated in situ for 7 days to a burn-up of 130 MWd/t. This test was performed to study the impact of steam-poor conditions and boric acid on the fission product chemistry. For the containment vessel, more specifically, the objective was to study iodine chemistry in an alkaline sump under evaporating conditions. The iodine results of the Phebus FPT2 test confirmed many of the essential features of iodine behaviour in the containment vessel provided by the first two Phebus tests, FPT0 and FPT1. These are the existence of an early gaseous iodine fraction, the persistence of low gaseous iodine concentrations and the importance of the sump in suppressing the iodine partitioning from sump to atmosphere. The main new insights provided by the Phebus FPT2 test were the iodine desorption from stainless steel walls deposits and the role of the evaporating sump in further iodine depletion in the containment atmosphere. The current paper presents an interpretation of

  10. Iodine nutritional status in Asturian schoolchildren.

    Science.gov (United States)

    Riestra Fernández, María; Menéndez Torre, Edelmiro; Díaz Cadórniga, Francisco; Fernández Fernández, Juan Carlos; Delgado Álvarez, Elías

    2017-11-01

    Iodine deficiency is a public health problem, and iodine nutritional status should therefore be regularly measured. To ascertain iodine nutritional status in Asturias and its relation to use of iodized salt and to other sociodemographic and nutritional parameters. A descriptive, observational study was conducted in a random sample of schoolchildren aged 5 to 14 years, in whom urinary iodine levels were measured by high-performance liquid chromatography. Families completed a survey on use of iodized salt, consumption of dairy products and fish, and sociodemographic data. The study sample consisted of 705 schoolchildren (51.1% females) with a mean age of 9.9 years (SD 2.6). In a total of 620 valid measurements, mean urinary iodine level was 204.1 μg/L (SD 120.6), while the median value was 180.7 μg/L (P 25 -P 75 : 124-252.3 μg/L, interquartile range 128.3 μg/L). Urinary iodine levels were y SED. Publicado por Elsevier España, S.L.U. All rights reserved.

  11. Iodine-Catalyzed Isomerization of Dimethyl Muconate

    Energy Technology Data Exchange (ETDEWEB)

    Settle, Amy E [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Berstis, Laura R [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Zhang, Shuting [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Rorrer, Nicholas [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Hu, Haiming [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Richards, Ryan [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Beckham, Gregg T [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Crowley, Michael F [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Vardon, Derek R [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-04-12

    cis,cis-Muconic acid is a platform biobased chemical that can be upgraded to drop-in commodity and novel monomers. Among the possible drop-in products, dimethyl terephthalate can be synthesized via esterification, isomerization, Diels-Alder cycloaddition, and dehydrogenation. The isomerization of cis,cis-dimethyl muconate (ccDMM) to the trans,trans-form (ttDMM) can be catalyzed by iodine; however, studies have yet to address (i) the mechanism and reaction barriers unique to DMM, and (ii) the influence of solvent, potential for catalyst recycle, and recovery of high-purity ttDMM. To address this gap, we apply a joint computational and experimental approach to investigate iodine-catalyzed isomerization of DMM. Density functional theory calculations identified unique regiochemical considerations due to the large number of halogen-diene coordination schemes. Both transition state theory and experiments estimate significant barrier reductions with photodissociated iodine. Solvent selection was critical for rapid kinetics, likely due to solvent complexation with iodine. Under select conditions, ttDMM yields of 95% were achieved in <1 h with methanol, followed by high purity recovery (>98%) with crystallization. Lastly, post-reaction iodine can be recovered and recycled with minimal loss of activity. Overall, these findings provide new insight into the mechanism and conditions necessary for DMM isomerization with iodine to advance the state-of-the-art for biobased chemicals.

  12. Hybrid adsorptive membrane reactor

    Science.gov (United States)

    Tsotsis, Theodore T [Huntington Beach, CA; Sahimi, Muhammad [Altadena, CA; Fayyaz-Najafi, Babak [Richmond, CA; Harale, Aadesh [Los Angeles, CA; Park, Byoung-Gi [Yeosu, KR; Liu, Paul K. T. [Lafayette Hill, PA

    2011-03-01

    A hybrid adsorbent-membrane reactor in which the chemical reaction, membrane separation, and product adsorption are coupled. Also disclosed are a dual-reactor apparatus and a process using the reactor or the apparatus.

  13. Co adsorption in kaolinite

    International Nuclear Information System (INIS)

    Souza, Eliel S.; Silva, Paulo S.C.

    2017-01-01

    Adsorption of metal ions in clay minerals has been used as an alternative to water and effluents treatment. Kaolinite is a clay mineral that presents low specific surface area and exchange ion capacity. Nevertheless, structural modifications can be achieved by means of acid or thermal activation. In this paper, it was studied the surface area of kaolinite/bentonite, kaolinite/activated carbon mixtures, thermal activated kaolinite and thermal activated kaolinite/activated carbon mixture. The mixture of kaolinite/activated carbon was tested for pH, contact time, interfering ions and initial concentration effects in the cobalt adsorption. Results showed that the optimized parameters are pH 6 and contact time of 30 min. Chromium acted as a competitive ion, zinc does not appear to have affected adsorption while iron seems to have favored it. Langmuir and Freundlich isotherms indicated that the adsorption of Co in the mixture of kaolinite/activated carbon is a spontaneous process. (author)

  14. Co adsorption in kaolinite

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Eliel S.; Silva, Paulo S.C., E-mail: eliel201019@hotmail.com, E-mail: pscsilva@ipen.br [Instituto de Pesquisas Energética s e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil)

    2017-07-01

    Adsorption of metal ions in clay minerals has been used as an alternative to water and effluents treatment. Kaolinite is a clay mineral that presents low specific surface area and exchange ion capacity. Nevertheless, structural modifications can be achieved by means of acid or thermal activation. In this paper, it was studied the surface area of kaolinite/bentonite, kaolinite/activated carbon mixtures, thermal activated kaolinite and thermal activated kaolinite/activated carbon mixture. The mixture of kaolinite/activated carbon was tested for pH, contact time, interfering ions and initial concentration effects in the cobalt adsorption. Results showed that the optimized parameters are pH 6 and contact time of 30 min. Chromium acted as a competitive ion, zinc does not appear to have affected adsorption while iron seems to have favored it. Langmuir and Freundlich isotherms indicated that the adsorption of Co in the mixture of kaolinite/activated carbon is a spontaneous process. (author)

  15. Dietary Iodine Intake of the Australian Population after Introduction of a Mandatory Iodine Fortification Programme

    Directory of Open Access Journals (Sweden)

    Karen Charlton

    2016-11-01

    Full Text Available To address mild iodine deficiency in Australia, a mandatory fortification program of iodised salt in bread was implemented in 2009. This study aimed to determine factors associated with achieving an adequate dietary iodine intake in the Australian population post-fortification, and to assess whether bread consumption patterns affect iodine intake in high-risk groups. Using nationally representative data of repeated 24-h dietary recalls from the 2011–2012 Australian National Nutrition and Physical Activity Survey, dietary iodine intakes and food group contributions were compared by age, socioeconomic status (SES, and geographical remoteness (N = 7735. The association between fortified bread intake and adequacy of iodine intake (meeting age and sex-specific Estimated Average Requirements was investigated using logistic regression models in women of childbearing age 14–50 years (n = 3496 and children aged 2–18 years (n = 1772. The effect of SES on bread consumption was further investigated in a sub group of children aged 5–9 years (n = 488. Main sources of iodine intake at the time of the survey were cereal and cereal products, followed by milk products and dishes. Differences in iodine intake and dietary iodine habits according to age, SES and location were found (p < 0.001 for women of child-bearing age. Fortified bread consumption at ≥100 g/day was associated with five times greater odds of achieving an adequate iodine intake (OR 5.0, 95% CI 4.96–5.13; p < 0.001 compared to lower bread consumption in women and 12 times in children (OR 12.34, 95% CI 1.71–89.26; p < 0.001. Disparities in dietary iodine intake exist within sectors of the Australian population, even after mandatory fortification of a staple food. On-going monitoring and surveillance of iodine status is required.

  16. Theoretical and experimental investigations on the behaviour of iodine during severe accidents: volatile iodine. Final report

    International Nuclear Information System (INIS)

    Funke, F.; Zeh, P.; Greger, G.U.; Hellmann, S.

    1999-01-01

    Analysis of the consequences of severe accidents in nuclear power plants requires knowledge of the behaviour of radionuclides relevant from the radiological viewpoint, especially the iodine. The current modelling of iodine behaviour is not conclusive, owing to insufficiently known data. This project is intended to eliminate some of these data gaps in critical areas. 350 tests on the radiation-induced oxidation of elemental iodine (I 2 ) in the containment atmosphere were performed yielding an extended database. Moreover, irradiation tests were performed on the formation and decomposition of ozone which is a reaction partner for I 2 . The reaction with ozone converts volatile I 2 into non-volatile iodine oxides or iodate. An improved kinetic modelling was developed for the iodine accident code IMPAIR. Now the model is valid also for steam-containing atmospheres and, additionally, considers dose rate and thus the actual ozone concentration. An assessment of the literature concludes that β and γ radiation have no different impact on iodine chemistry and thus do not need to be modelled separately in iodine accident codes. An assessment of the literature shows a partly significant chemical interaction of volatile iodine with aerosols. Since such reactions lead to a faster decrease of volatile iodine at least at high aerosol concentrations, a modelling should be foreseen in the future. In the frame of the international ISP-41 project, calculations to an integral test in the Canadian Radioiodine Test Facility (RTF) were performed with IMPAIR. The existing model of the radiation-induced I 2 formation in the sump in IMPAIR is identified as a weakness requiring future improvement. A theoretical assessment on the iodine chemistry in the droplets of a spray system concludes that a modelling is necessary in case of spraying with fresh water, and that this is already contained in available spray models. During recirculation spraying in an examplary, hypothetical EPR case, no

  17. Experimentally-induced dissociation impairs visual memory.

    Science.gov (United States)

    Brewin, Chris R; Mersaditabari, Niloufar

    2013-12-01

    Dissociation is a phenomenon common in a number of psychological disorders and has been frequently suggested to impair memory for traumatic events. In this study we explored the effects of dissociation on visual memory. A dissociative state was induced experimentally using a mirror-gazing task and its short-term effects on memory performance were investigated. Sixty healthy individuals took part in the experiment. Induced dissociation impaired visual memory performance relative to a control condition; however, the degree of dissociation was not associated with lower memory scores in the experimental group. The results have theoretical and practical implications for individuals who experience frequent dissociative states such as patients with posttraumatic stress disorder (PTSD). Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Diffractive dissociation and new quarks

    International Nuclear Information System (INIS)

    White, A.R.

    1983-04-01

    We argue that the chiral limit of QCD can be identified with the strong (diffractive dissociation) coupling limit of reggeon field theory. Critical Pomeron scaling at high energy must then be directly related to an infra-red fixed-point of massless QCD and so requires a large number of flavors. This gives a direct argument that the emergence of diffraction-peak scaling, KNO scaling etc. at anti p-p colliders are evidence of a substantial quark structure still to be discovered

  19. [Characteristics of Bacillus cereus dissociants].

    Science.gov (United States)

    Doroshenko, E V; Loĭko, N G; Il'inskaia, O N; Kolpakov, A I; Gornova, I B; Klimanova, E V; El'-Registan, G I

    2001-01-01

    The autoregulation of the phenotypic (populational) variability of the Bacillus cereus strain 504 was studied. The isolated colonial morphotypes of this bacterium were found to differ in their growth characteristics and the synthesis of extracellular proteases. The phenotypic variabilities of vegetative proliferating cells and those germinated from endospores and cystlike refractory cells were different. Bacterial variants also differed in the production of the d1 and d2 factors (the autoinducers of dormancy and autolysis, respectively) and sensitivity to them. The possible role of these factors in the dissociation of microorganisms is discussed.

  20. Structure sensitivity in adsorption

    DEFF Research Database (Denmark)

    Hammer, Bjørk; Nielsen, Ole Holm; Nørskov, Jens Kehlet

    1997-01-01

    The structure sensitivity of CO adsorption on different flat, stepped, kinked and reconstructed Pt surfaces is studied using large-scale density-functional calculations. We find an extremely strong structure sensitivity in the adsorption energy with variations up to 1 eV (or 100%) from one...... structure to the next. We propose a model to explain this behavior, and use it to discuss more generally the origin of structure sensitivity in heterogeneous catalysis....

  1. Collision-induced dissociation of diatomic ions

    International Nuclear Information System (INIS)

    Los, J.; Govers, T.R.

    1978-01-01

    An attempt is made to illustrate how mass spectrometric studies of dissociation in diatomic molecular ions can provide information on the dynamics of these collisions and on the predissociative states involved. Restriction is made to primary beam energies of the order of at least keV. The review covers the dynamics of dissociation, experimental techniques, direct dissociation in heavy-particle collisions, and translational spectroscopy. 120 references

  2. Mirror Writing and a Dissociative Identity Disorder

    OpenAIRE

    Le, Catherine; Smith, Joyce; Cohen, Lewis

    2009-01-01

    Individuals with dissociative identity disorder (DID) have been known to show varied skills and talents as they change from one dissociative state to another. For example, case reports have described people who have changed their handedness or have spoken foreign languages during their dissociative states. During an interview with a patient with DID, a surprising talent emerged when she wrote a sentence for the Folstein Mini-Mental State Exam—mirror writing. It is not known whether her mirror...

  3. Iodine nutrition status in lactating mothers residing in countries with mandatory and voluntary iodine fortification programs: an updated systematic review.

    Science.gov (United States)

    Nazeri, Pantea; Mirmiran, Parvin; Shiva, Niloofar; Mehrabi, Yadollah; Mojarrad, Mehdi; Azizi, Fereidoun

    2015-06-01

    The aim of this review is to assess data available on iodine nutrition status in lactating mothers residing in countries with mandatory and voluntary iodine fortification programs and/or iodine supplementation. A systematic review was conducted by searching articles published between 1964 and 2013 in Pub Med, ISI Web, and Cochrane Library using iodine nutrition, lactation, iodine supplementation, and iodine fortification as keywords for titles and/or abstracts. Relevant articles were included if they reported urinary iodine concentration (UIC) in lactating mothers and, if determined, the type of iodine fortification program and/or iodine supplementation. Forty-two studies met the inclusion criteria. Among these, 21 studies assessed lactating mothers in countries with a mandatory iodine fortification program, 17 studies were from countries with voluntary and/or without iodine fortification programs, and four studies assessed iodine nutrition status in lactating mothers undergoing iodine supplementation. Among countries with mandatory iodine fortification programs, the range of salt iodization level in lactating mothers with a UIC 100 μg/L, it was between 15 and 60 ppm. Levels of UIC Chile, Iran, Mongolia, New Guinea, and Nigeria, the median or mean of UIC was >100 μg/L. There was a median or mean UIC program was voluntary, including Switzerland, Australia, New Zealand, Ireland, and Germany. However, in some countries with voluntary iodine fortification programs, such as the United States, Spain, and Japan, a mean or median UIC of >100 μg/L has been reported. Although universal salt iodization is still the most feasible and cost-effective approach for iodine deficiency control in pregnant and lactating mothers, UIC in lactating mothers of most countries with voluntary programs and in areas with mandatory iodine fortification is still within the iodine deficiency range, indicating that iodine supplementation in daily prenatal vitamin/mineral supplements in

  4. Mirror Writing and a Dissociative Identity Disorder

    Directory of Open Access Journals (Sweden)

    Catherine Le

    2009-01-01

    Full Text Available Individuals with dissociative identity disorder (DID have been known to show varied skills and talents as they change from one dissociative state to another. For example, case reports have described people who have changed their handedness or have spoken foreign languages during their dissociative states. During an interview with a patient with DID, a surprising talent emerged when she wrote a sentence for the Folstein Mini-Mental State Exam—mirror writing. It is not known whether her mirror writing had a deeper level of meaning; however, it does emphasize the idiosyncratic nature of dissociative identity disorder.

  5. Mirror writing and a dissociative identity disorder.

    Science.gov (United States)

    Le, Catherine; Smith, Joyce; Cohen, Lewis

    2009-01-01

    Individuals with dissociative identity disorder (DID) have been known to show varied skills and talents as they change from one dissociative state to another. For example, case reports have described people who have changed their handedness or have spoken foreign languages during their dissociative states. During an interview with a patient with DID, a surprising talent emerged when she wrote a sentence for the Folstein Mini-Mental State Exam-mirror writing. It is not known whether her mirror writing had a deeper level of meaning; however, it does emphasize the idiosyncratic nature of dissociative identity disorder.

  6. A rechargeable iodine-carbon battery that exploits ion intercalation and iodine redox chemistry.

    Science.gov (United States)

    Lu, Ke; Hu, Ziyu; Ma, Jizhen; Ma, Houyi; Dai, Liming; Zhang, Jintao

    2017-09-13

    Graphitic carbons have been used as conductive supports for developing rechargeable batteries. However, the classic ion intercalation in graphitic carbon has yet to be coupled with extrinsic redox reactions to develop rechargeable batteries. Herein, we demonstrate the preparation of a free-standing, flexible nitrogen and phosphorus co-doped hierarchically porous graphitic carbon for iodine loading by pyrolysis of polyaniline coated cellulose wiper. We find that heteroatoms could provide additional defect sites for encapsulating iodine while the porous carbon skeleton facilitates redox reactions of iodine and ion intercalation. The combination of ion intercalation with redox reactions of iodine allows for developing rechargeable iodine-carbon batteries free from the unsafe lithium/sodium metals, and hence eliminates the long-standing safety issue. The unique architecture of the hierarchically porous graphitic carbon with heteroatom doping not only provides suitable spaces for both iodine encapsulation and cation intercalation but also generates efficient electronic and ionic transport pathways, thus leading to enhanced performance.Carbon-based electrodes able to intercalate Li + and Na + ions have been exploited for high performing energy storage devices. Here, the authors combine the ion intercalation properties of porous graphitic carbons with the redox chemistry of iodine to produce iodine-carbon batteries with high reversible capacities.

  7. Longitudinal study of iodine in toenails following IV administration of an iodine-containing contrast agent

    International Nuclear Information System (INIS)

    Spate, V.L.; Morris, J.S.; Nichols, T.A.; Baskett, C.K.; Mason, M.M.; Horsman, T.L.; McDougall, I.R.

    1998-01-01

    The literature on the relationship between diet and thyroid cancer (TC) risk and the higher incidence of TC among Asian immigrants to the US compared to second and third generation subgroups has prompted epidemiologists to hypothesize that increased levels of iodine consumption may be associated with TC risk, particularly among persons with a history of clinical or subclinical thyroid dysfunction. At the University of Missouri Research Reactor (MURR), we have applied epiboron neutron activation analysis to investigate human nails as a dietary monitor for iodine. Preliminary studies have indicated a positive correlation between dietary iodine intake and the concentration of iodine in toenails. However, these studies are confounded by high iodine levels (up to 30 ppm) in approximately 5% of the nails studied. We hypothesize that, in the subjects we have studied, the high iodine levels may be due to iodine-containing medications, in particular contrast-agents containing iopamidol. This paper will report on longitudinal studies using contrast agent subjects who where followed-up for almost two years compared to a longitudinal control and a population mean. Based on this study, we suggest that iodine-containing contrast agents contaminate nail samples via non-specific binding in the short term followed by incorporation in the nail as a result of absorption. (author)

  8. Determination of iodine and iodine compounds in marine samples by ICPMS and HPLC-ICPMS

    DEFF Research Database (Denmark)

    Hansen, Maiken Sødergreen; Lewandowski, Daniel Jacob; Rasmussen, Rie Romme

    2014-01-01

    seaweed and fish, which contain elevated levels of iodine (fish typically 1-10 mg/kg and seaweed up to 8000 mg/kg). These marine food items may contain different iodine species, which may have different bioavailability and toxicity, and hence there is an increased interest in developing analytical methods...

  9. Thyroid volume and urinary iodine in European schoolchildren: standardization of values for assessment of iodine deficiency

    NARCIS (Netherlands)

    Delange, F.; Benker, G.; Caron, P.; Eber, O.; Ott, W.; Peter, F.; Podoba, J.; Simescu, M.; Szybinsky, Z.; Vertongen, F.; Vitti, P.; Wiersinga, W.; Zamrazil, V.

    1997-01-01

    Up to 1992, most European countries used to be moderately to severely iodine deficient. The present study aimed at evaluating possible changes in the status of iodine nutrition in 12 European countries during the past few years. Thyroid volume was measured by ultrasonography in 7599 schoolchildren

  10. The impact of iodised salt or iodine supplements on iodine status during pregnancy lactation and infancy

    NARCIS (Netherlands)

    Zimmermann, M.B.

    2007-01-01

    Objectives: Monitoring of iodine status during pregnancy, lactation and infancy is difficult as there are no established reference criteria for urinary iodine concentration (UI) for these groups; so it is uncertain whether iodized salt programs meet the needs of these life stages. Design and

  11. A review on adsorption refrigeration technology and adsorption deterioration in physical adsorption systems

    Energy Technology Data Exchange (ETDEWEB)

    Wang, D.C.; Li, Y.H. [College of Electromechanical Engineering, Qingdao University, 308 Ningxia Road, Qingdao 266071 (China); Laboratory of Fiber Materials and Modern Textile, the Growing Base for State Key Laboratory, Qingdao University, 308 Ningxia Road, Qingdao 266071 (China); Li, D.; Zhang, J.P. [College of Electromechanical Engineering, Qingdao University, 308 Ningxia Road, Qingdao 266071 (China); Xia, Y.Z. [Laboratory of Fiber Materials and Modern Textile, the Growing Base for State Key Laboratory, Qingdao University, 308 Ningxia Road, Qingdao 266071 (China)

    2010-01-15

    As one kind of environmentally friendly refrigeration, the adsorption refrigeration has attracted many attentions in resent decades. This paper introduces the researches of adsorption refrigeration systems with the commonly used working pairs, advanced adsorption cycles, heat and mass transfer enhancement and attempts of adsorption refrigeration applications. Poor heat and mass transfer problem is a bottleneck to prevent the improvements of the adsorption refrigeration technique. Two ways to enhance the heat and mass transfer are discussed in this paper. The adsorption deterioration of adsorbent, another obstacle to physical adsorption refrigeration applications, is also pointed out. And the possible reasons and the possible methods are analyzed. (author)

  12. Dissociative symptoms and dissociative disorder comorbidity in patients with obsessive-compulsive disorder.

    Science.gov (United States)

    Belli, Hasan; Ural, Cenk; Vardar, Melek Kanarya; Yesılyurt, Sema; Oncu, Fatıh

    2012-10-01

    The present study attempted to assess the dissociative symptoms and overall dissociative disorder comorbidity in patients with obsessive-compulsive disorder (OCD). In addition, we examined the relationship between the severity of obsessive-compulsive symptoms and dissociative symptoms. All patients admitted for the first time to the psychiatric outpatient unit were included in the study. Seventy-eight patients had been diagnosed as having OCD during the 2-year study period. Patients had to meet the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for OCD. Most (76.9%; n = 60) of the patients were female, and 23.1% (n = 18) of the patients were male. Dissociation Questionnaire was used to measure dissociative symptoms. The Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition Dissociative Disorders interviews and Yale-Brown Obsessive Compulsive Checklist and Severity Scale were used. Eleven (14%) of the patients with OCD had comorbid dissociative disorder. The most prevalent disorder in our study was dissociative depersonalization disorder. Dissociative amnesia and dissociative identity disorder were common as well. The mean Yale-Brown score was 23.37 ± 7.27 points. Dissociation Questionnaire scores were between 0.40 and 3.87 points, and the mean was 2.23 ± 0.76 points. There was a statistically significant positive correlation between Yale-Brown points and Dissociation Questionnaire points. We conclude that dissociative symptoms among patients with OCD should alert clinicians for the presence of a chronic and complex dissociative disorder. Clinicians may overlook an underlying dissociative process in patients who have severe symptoms of OCD. However, a lack of adequate response to cognitive-behavioral and drug therapy may be a consequence of dissociative process. Copyright © 2012 Elsevier Inc. All rights reserved.

  13. Dissociative identity disorder: Medicolegal challenges.

    Science.gov (United States)

    Farrell, Helen M

    2011-01-01

    Persons with dissociative identity disorder (DID) often present in the criminal justice system rather than the mental health system and perplex experts in both professions. DID is a controversial diagnosis with important medicolegal implications. Defendants have claimed that they committed serious crimes, including rape or murder, while they were in a dissociated state. Asserting that their alter personality committed the bad act, defendants have pleaded not guilty by reason of insanity (NGRI). In such instances, forensic experts are asked to assess the defendant for DID and provide testimony in court. Debate continues over whether DID truly exists, whether expert testimony should be allowed into evidence, and whether it should exculpate defendants for their criminal acts. This article reviews historical and theoretical perspectives on DID, presents cases that illustrate the legal implications and controversies of raising an insanity defense based on multiple personalities, and examines the role of forensic experts asked to comment on DID with the goal of assisting clinicians in the medicolegal assessment of DID in relation to crimes.

  14. Intravascular enhancement with identical iodine delivery rate using different iodine contrast media in a circulation phantom.

    Science.gov (United States)

    Mihl, Casper; Wildberger, Joachim E; Jurencak, Tomas; Yanniello, Michael J; Nijssen, Estelle C; Kalafut, John F; Nalbantov, Georgi; Mühlenbruch, Georg; Behrendt, Florian F; Das, Marco

    2013-11-01

    Both iodine delivery rate (IDR) and iodine concentration are decisive factors for vascular enhancement in computed tomographic angiography. It is unclear, however, whether the use of high-iodine concentration contrast media is beneficial to lower iodine concentrations when IDR is kept identical. This study evaluates the effect of using different iodine concentrations on intravascular attenuation in a circulation phantom while maintaining a constant IDR. A circulation phantom with a low-pressure venous compartment and a high-pressure arterial compartment simulating physiological circulation parameters was used (heart rate, 60 beats per minute; stroke volume, 60 mL; blood pressure, 120/80 mm Hg). Maintaining a constant IDR (2.0 g/s) and a constant total iodine load (20 g), prewarmed (37°C) contrast media with differing iodine concentrations (240-400 mg/mL) were injected into the phantom using a double-headed power injector. Serial computed tomographic scans at the level of the ascending aorta (AA), the descending aorta (DA), and the left main coronary artery (LM) were obtained. Total amount of contrast volume (milliliters), iodine delivery (grams of iodine), peak flow rate (milliliter per second), and intravascular pressure (pounds per square inch) were monitored using a dedicated data acquisition program. Attenuation values in the AA, the DA, and the LM were constantly measured (Hounsfield unit [HU]). In addition, time-enhancement curves, aortic peak enhancement, and time to peak were determined. All contrast injection protocols resulted in similar attenuation values: the AA (516 [11] to 531 [37] HU), the DA (514 [17] to 531 [32] HU), and the LM (490 [10] to 507 [17] HU). No significant differences were found between the AA, the DA, and the LM for either peak enhancement (all P > 0.05) or mean time to peak (AA, 19.4 [0.58] to 20.1 [1.05] seconds; DA, 21.1 [1.0] to 21.4 [1.15] seconds; LM, 19.8 [0.58] to 20.1 [1.05] seconds). This phantom study demonstrates that

  15. The placenta as a compensatory iodine storage organ.

    LENUS (Irish Health Repository)

    Burns, Robert

    2011-05-01

    The production of iodine-containing thyroid hormones necessary for brain development in the fetus depends not only on maternal dietary intake but also on placental iodine transport. The optimum level of iodine nutrition during pregnancy and the proportion of the pregnant population reaching this level have previously been evaluated. Little information exists on the ability of the placenta to either accumulate or store iodine. This study aims to investigate iodine uptake and tissue iodine content within placental tissue obtained from women delivering at term.

  16. Iodine-129 Dose in LLW Disposal Facility Performance Assessments

    International Nuclear Information System (INIS)

    Wilhite, E.L.

    1999-01-01

    Iodine-129 has the lowest Performance Assessment derived inventory limit in SRS disposal facilities. Because iodine is concentrated in the body to one organ, the thyroid, it has been thought that dilution with stable iodine would reduce the dose effects of 129I.Examination of the dose model used to establish the Dose conversion factor for 129I shows that, at the levels considered in performance assessments of low-level waste disposal facilities, the calculated 129I dose already accounts for ingestion of stable iodine. At higher than normal iodine ingestion rates, the uptake of iodine by the thyroid itself decrease, which effectively cancels out the isotopic dilution effect

  17. [Application of iodine metabolism analysis methods in thyroid diseases].

    Science.gov (United States)

    Han, Jian-hua; Qiu, Ling

    2013-08-01

    The main physiological role of iodine in the body is to synthesize thyroid hormone. Both iodine deficiency and iodine excess can lead to severe thyroid diseases. While its role in thyroid diseases has increasingly been recognized, few relevant platforms and techniques for iodine detection have been available in China. This paper summarizes the advantages and disadvantages of currently iodine detection methods including direct titration, arsenic cerium catalytic spectrophotometry, chromatography with pulsed amperometry, colorimetry based on automatic biochemistry, inductively coupled plasma mass spectrometry, so as to optimize the iodine nutrition for patients with thyroid diseases.

  18. Mixed-layered bismuth--oxygen--iodine materials for capture and waste disposal of radioactive iodine

    Science.gov (United States)

    Krumhansl, James L; Nenoff, Tina M

    2015-01-06

    Materials and methods of synthesizing mixed-layered bismuth oxy-iodine materials, which can be synthesized in the presence of aqueous radioactive iodine species found in caustic solutions (e.g. NaOH or KOH). This technology provides a one-step process for both iodine sequestration and storage from nuclear fuel cycles. It results in materials that will be durable for repository conditions much like those found in Waste Isolation Pilot Plant (WIPP) and estimated for Yucca Mountain (YMP). By controlled reactant concentrations, optimized compositions of these mixed-layered bismuth oxy-iodine inorganic materials are produced that have both a high iodine weight percentage and a low solubility in groundwater environments.

  19. Mixed-layered bismuth-oxygen-iodine materials for capture and waste disposal of radioactive iodine

    Science.gov (United States)

    Krumhansl, James L; Nenoff, Tina M

    2013-02-26

    Materials and methods of synthesizing mixed-layered bismuth oxy-iodine materials, which can be synthesized in the presence of aqueous radioactive iodine species found in caustic solutions (e.g. NaOH or KOH). This technology provides a one-step process for both iodine sequestration and storage from nuclear fuel cycles. It results in materials that will be durable for repository conditions much like those found in Waste Isolation Pilot Plant (WIPP) and estimated for Yucca Mountain (YMP). By controlled reactant concentrations, optimized compositions of these mixed-layered bismuth oxy-iodine inorganic materials are produced that have both a high iodine weight percentage and a low solubility in groundwater environments.

  20. Dimethyl sulfoxide complexing with iodine

    Energy Technology Data Exchange (ETDEWEB)

    Borovikov, Yu Ya; Serguchev, Yu A; Staninets, V I

    1986-01-01

    Dielectrometry, conductometry, IR-spectroscopy are used to study dimethyl sulfoxide complexing with iodine in binary system and in CCl/sub 4/, C/sub 6/H/sub 6/, C/sub 6/H/sub 5/Cl, C/sub 6/H/sub 5/CF/sub 3/, 1, 2-dichloroethane solutions. Complexes of 1:1 composition are formed in solutions, in the binary system of 2:1 and 2:2 composition. I/sub 2/ molecules add to oxygen atoms. In CCl/sub 4/ and in binary system gradual transformation of so called external charge transfer complexes (CTC-1) to internal ones (CTC-2) that are described by the 1st order reaction kinetic equations is observed. On dissolution of CTC of 2:2 composition they disproportionate into two CTC molecules 1:1. Enthalpy of forming CTC-1 1:1 is approximately 4 kcal/mol, CTC-2 1:1 - 8, CTC-1 2:1 - 8 kcal/mol.

  1. From dissociation to trauma? Individual differences in dissociation as predictor of 'trauma' perception

    NARCIS (Netherlands)

    Rassin, Eric; van Rootselaar, Anne-Fleur

    2006-01-01

    In clinical literature, dissociative complaints are generally considered to be the result of traumatic experiences. However, it has been argued that dissociative complaints, in turn, may indulge over-reporting of traumatic experiences. Hence, correlations between dissociation and self-reported

  2. Dissociation in patients with dissociative seizures: relationships with trauma and seizure symptoms.

    Science.gov (United States)

    Pick, S; Mellers, J D C; Goldstein, L H

    2017-05-01

    This study aimed to extend the current understanding of dissociative symptoms experienced by patients with dissociative (psychogenic, non-epileptic) seizures (DS), including psychological and somatoform types of symptomatology. An additional aim was to assess possible relationships between dissociation, traumatic experiences, post-traumatic symptoms and seizure manifestations in this group. A total of 40 patients with DS were compared with a healthy control group (n = 43), matched on relevant demographic characteristics. Participants completed several self-report questionnaires, including the Multiscale Dissociation Inventory (MDI), Somatoform Dissociation Questionnaire-20, Traumatic Experiences Checklist and the Post-Traumatic Diagnostic Scale. Measures of seizure symptoms and current emotional distress (Hospital Anxiety and Depression Scale) were also administered. The clinical group reported significantly more psychological and somatoform dissociative symptoms, trauma, perceived impact of trauma, and post-traumatic symptoms than controls. Some dissociative symptoms (i.e. MDI disengagement, MDI depersonalization, MDI derealization, MDI memory disturbance, and somatoform dissociation scores) were elevated even after controlling for emotional distress; MDI depersonalization scores correlated positively with trauma scores while seizure symptoms correlated with MDI depersonalization, derealization and identity dissociation scores. Exploratory analyses indicated that somatoform dissociation specifically mediated the relationship between reported sexual abuse and DS diagnosis, along with depressive symptoms. A range of psychological and somatoform dissociative symptoms, traumatic experiences and post-traumatic symptoms are elevated in patients with DS relative to healthy controls, and seem related to seizure manifestations. Further studies are needed to explore peri-ictal dissociative experiences in more detail.

  3. Active molecular iodine photochemistry in the Arctic

    Energy Technology Data Exchange (ETDEWEB)

    Raso, Angela R.; Custard, Kyle D.; May, Nathaniel W.; Tanner, David; Newburn, Matthew K.; Walker, Lawrence R.; Moore, Ronald J.; Huey, L. G.; Alexander, Lizabeth; Shepson, Paul B.; Pratt, Kerri A.

    2017-09-05

    During springtime, the Arctic atmospheric boundary layer undergoes frequent rapid depletions in ozone and gaseous elemental mercury due to reactions with halogen atoms, influencing atmospheric composition and pollutant fate. Although bromine chemistry has been shown to initiate ozone depletion events, and it has long been hypothesized that iodine chemistry may contribute, no previous measurements of molecular iodine (I2) have been reported in the Arctic. Iodine chemistry also contributes to atmospheric new particle formation and therefore cloud properties and radiative forcing. Here we present Arctic atmospheric I2 and snowpack iodide (I-) measurements, which were conducted near Utqiagvik, AK, in February 2014. Using chemical ionization mass spectrometry, I2 was observed in the atmosphere at mole ratios of 0.3–1.0 ppt, and in the snowpack interstitial air at mole ratios up to 22 ppt under natural sunlit conditions and up to 35 ppt when the snowpack surface was artificially irradiated, suggesting a photochemical production mechanism. Further, snow meltwater I-measurements showed enrichments of up to ~1,900 times above the seawater ratio of I-/Na+, consistent with iodine activation and recycling. Modeling shows that observed I2 levels are able to significantly increase ozone depletion rates, while also producing iodine monoxide (IO) at levels recently observed in the Arctic. These results emphasize the significance of iodine chemistry and the role of snowpack photochemistry in Arctic atmospheric composition, and imply that I2 is likely a dominant source of iodine atoms in the Arctic.

  4. Absorption of gaseous iodine by water droplets

    International Nuclear Information System (INIS)

    Albert, M.F.

    1985-07-01

    A new model has been developed for predicting the rate at which gaseous molecular iodine is absorbed by water sprays. The model is a quasi-steady state mass transfer model that includes the iodine hydrolysis reactions. The parameters of the model are spray drop size, initial concentration of the gas and liquid phases, temperature, pressure, buffered or unbuffered spray solution, spray flow rate, containment diameter and drop fall height. The results of the model were studied under many values of these parameters. Plots of concentration of iodine species in the drop versus time have been produced by varying the initial gas phase concentration of molecular iodine over the range of 1 x 10 -5 moles/liter to 1 x 10 -10 moles/liter and a drop size of 1000 microns. Results from the model are compared to results available from Containment Systems Experiments at Pacific Northwest Laboratory. The difference between the model predictions and the experimental data ranges from -120.5% to 68.0% with the closest agreement 7.7%. The new spray model is also compared to previously existing spray models. At high concentrations of gaseous molecular iodine, the new spray model is considered to be less accurate but at low concentrations, the new model predicts results that are closer to the experimental data than the model called the realistic model from WASH-1329. Inclusion of the iodine hydrolysis reaction is shown to be a feature important to a model intended for determining the removal of molecular iodine over a wide range of conditions

  5. Adsorption of uranium on halloysite

    International Nuclear Information System (INIS)

    Kilislioglu, A.; Bilgin, B.

    2002-01-01

    Adsorption of uranium (U(VI)) from aqueous solutions on halloysite type clay was studied as a function of amount of adsorbent, initial concentration and pH. The values of adsorption data were fitted to Freundlich, Langmuir and Dubinin-Radushkevich (D-R) adsorption isotherms. The mean energy of adsorption was calculated as 5.91 kJ/mol from D-R adsorption isotherm. Lagergren and Bangham equation has been used for dynamic modelling of process and the rate constants of adsorption of uranium on halloysite type clay were calculated at 293, 313 and 333 K. In order to explain the mechanism of adsorption reaction, the rate constants were calculated at high and low uranium concentrations. Adsorption reaction was studied at 293, 303, 313, 323 and 333 K for halloysite type clay and also thermodynamic constants have been calculated. The results show that the adsorption reaction was endothermic and more spontaneous at high temperature. (orig.)

  6. Adsorption of uranium on halloysite

    Energy Technology Data Exchange (ETDEWEB)

    Kilislioglu, A.; Bilgin, B. [Istanbul Univ. (Turkey). Faculty of Engineering

    2002-07-01

    Adsorption of uranium (U(VI)) from aqueous solutions on halloysite type clay was studied as a function of amount of adsorbent, initial concentration and pH. The values of adsorption data were fitted to Freundlich, Langmuir and Dubinin-Radushkevich (D-R) adsorption isotherms. The mean energy of adsorption was calculated as 5.91 kJ/mol from D-R adsorption isotherm. Lagergren and Bangham equation has been used for dynamic modelling of process and the rate constants of adsorption of uranium on halloysite type clay were calculated at 293, 313 and 333 K. In order to explain the mechanism of adsorption reaction, the rate constants were calculated at high and low uranium concentrations. Adsorption reaction was studied at 293, 303, 313, 323 and 333 K for halloysite type clay and also thermodynamic constants have been calculated. The results show that the adsorption reaction was endothermic and more spontaneous at high temperature. (orig.)

  7. Breast-Milk Iodine Concentrations and Iodine Levels of Infants According to the Iodine Status of the Country of Residence: A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Nazeri, Pantea; Kabir, Ali; Dalili, Hosein; Mirmiran, Parvin; Azizi, Fereidoun

    2018-01-01

    Iodine, an essential micronutrient, plays a critical role in normal growth and development, especially during the first two years of life. This systematic review and meta-analysis is among the first to evaluate breast-milk iodine concentrations and infant iodine status in countries characterized by iodine sufficiency or deficiency. PubMed, Web of Science, Cochrane Library, Google Scholar, and other relevant databases, as well as reference lists of previous reviews, were searched for relevant studies published between 1986 and 2016. Mean or median breast-milk and infant urinary iodine concentrations, along with other relevant data, were extracted from eligible studies. Each study was assessed for quality and risk of bias. Of the 496 identified studies, 57 met the criteria for inclusion in the meta-analysis. The mean (confidence interval [CI]) iodine concentrations in maternal colostrum were 152.0 μg/L [CI 106.2-198.7 μg/L] and 57.8 μg/L [CI 41.4-74.1 μg/L] in iodine-sufficient and -deficient countries, respectively, indicating a significant difference between the two iodine statuses. By contrast, the corresponding values in mature milk did not differ significantly between mothers in iodine-sufficient and -deficient countries (71.5 μg/L [CI 51.0-92.0 μg/L] and 28.0 μg/L [CI -13.8 to 69.9 μg/L], respectively]. The weighted urinary iodine levels [CIs] of breast-fed infants in iodine-sufficient countries were significantly higher than those in iodine-deficient countries (164.5 μg/L [CI 116.4-212.7 μg/L] vs. 70.4 μg/L [CI 46.2-94.6 μg/L]). Similarly, a significant difference was observed in the pooled estimates of urinary iodine levels [CIs] among formula-fed infants in iodine-sufficient versus iodine-deficient countries (310.3 μg/L [CI 287.4-342.1 μg/L] vs. 38.3 μg/L [CI 23.4-53.2 μg/L]). The meta-analysis reveals that in iodine-sufficient countries, the mean iodine concentrations in colostrum and mature breast milk

  8. Clinical and Biochemical Uses of Stable Iodine Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Koutras, D. A. [Thyroid Section, Alexandra Hospital, Athens (Greece)

    1970-07-01

    Iodine and thyroid function are closely linked, since the only known role of iodine is its participation in the synthesis of thyroid hormones. Iodine metabolism may be represented as a metabolic cycle consisting of three main pools: the Plasma Inorganic Iodine (PIl) pool into which dietary iodine goes and from where it is either taken up by the thyroid or excreted by the kidneys, the intrathyroidal iodine pool, where. thyroid hormone synthesis occurs, and finally the peripheral pool of thyroid hormones, of which about 80% are deiodinated and 20% excreted with the faeces. Endemic goitre is usually due to iodine deficiency. There is no renal homeostatic mechanism to keep the PII level constant, and so adaptation to iodine deficiency occurs by increasing the thyroidal iodide clearance rate. Stable iodine measurements are necessary for a complete study of iodine metabolism. Estimates of the serum Protein-Bound Iodine (PBl) are the best index of thyroid function, estimates of the PII and of the urinary iodine are the best indices of iodine nutrition. (author)

  9. Teratology public affairs committee position paper: iodine deficiency in pregnancy.

    Science.gov (United States)

    Obican, Sarah G; Jahnke, Gloria D; Soldin, Offie P; Scialli, Anthony R

    2012-09-01

    Iodine deficiency is an important nutritional deficiency, with more than 2 billion people worldwide estimated to be at risk. The developing fetus and young children are particularly at risk. During pregnancy and lactation, iodine requirements increase, whether in iodine-poor or iodine-sufficient countries, making the mother and the developing fetus vulnerable. The American Thyroid Association (ATA) recommends 250 micrograms per day of iodine intake for pregnant and lactating women. The thyroid gland is able to adapt to the changes associated with pregnancy as long as sufficient iodine is present. Dietary intake is the sole source of iodine, which is essential to the synthesis of thyroid hormones. Iodine is found in multiple dietary sources including iodized salt, dairy products, seaweed, and fish. Prenatal vitamins containing iodine are a good source of iodine, but iodine content in multivitamin supplements is highly variable. Congenital hypothyroidism is associated with cretinism. Clinical hypothyroidism has been associated with increased risk of poor perinatal outcome including prematurity, low birth weight, miscarriage, preeclampsia, fetal death, and impaired fetal neurocognitive development. Subclinical hypothyroidism is also associated with poor pregnancy outcomes and potential fetal neurocognitive deficits, but the data are more variable than those for clinical hypothyroidism. We concur with the ATA recommendation that all pregnant and lactating women should ingest (through diet and supplements) 250 micrograms of iodine daily. To achieve this goal, we recommend that all pregnant and lactating women take daily iodine supplementation of 150 micrograms. Copyright © 2012 Wiley Periodicals, Inc.

  10. The kinetic study of oxidation of iodine by hydrogen peroxide

    International Nuclear Information System (INIS)

    Cantrel, L.; Chopin, J.

    1996-01-01

    Iodine chemistry is one of the most important subjects of research in the field of reactor safety because this element can form volatile species which represent a biological hazard for environment. As the iodine and the peroxide are both present in the sump of the containment in the event of a severe accident on a light water nuclear reactor, it can be important to improve the knowledge on the reaction of oxidation of iodine by hydrogen peroxide. The kinetics of iodine by hydrogen peroxide has been studied in acid solution using two different analytical methods. The first is a UV/Vis spectrophotometer which records the transmitted intensity at 460 nm as a function of time to follow the decrease of iodine concentration, the second is an amperometric method which permits to record the increase of iodine+1 with time thanks to the current of reduction of iodine+1 to molecular iodine. The iodine was generated by Dushman reaction and the series of investigations were made at 40 o C in a continuous stirring tank reactor. The influence of the initial concentrations of iodine, iodate, hydrogen peroxide, H + ions has been determined. The kinetics curves comprise two distinct chemical phases both for molecular iodine and for iodine+1. The relative importance of the two processes is connected to the initial concentrations of [I 2 ], [IO 3 - ], [H 2 O 2 ] and [H + ]. A rate law has been determined for the two steps for molecular iodine. (author) figs., tabs., 22 refs

  11. Dissociation and the Development of Psychopathology.

    Science.gov (United States)

    Putnam, Frank W.; Trickett, Penelope K.

    This paper reviews the research on dissociation and the development of psychopathology in children and adolescents. Definitions and dimensions of dissociation are addressed, noting its range from normative daydreaming to the extremes found in individuals with multiple personality disorder. Memory dysfunctions, disturbances of identity, passive…

  12. Inflight dissociation of zircon in air plasma

    Energy Technology Data Exchange (ETDEWEB)

    Yugeswaran, S; Selvarajan, V [Bharathiar University, Coimbatore 641046 (India); Ananthapadmanabhan, P V; Thiyagarajan, T K [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Mumbai - 400 085 (India); Nair, Janardhanan [Ion Arc Technologies Pvt Ltd, Coimbatore (India)

    2010-02-01

    Thermal dissociation of zircon can be conveniently carried out in a plasma reactor, which is characterized by high temperature, high energy density and high quench rate. Zirconia is recovered from this partially dissociated zircon by alkali leaching. Dissociation of zircon has been conventionally carried out in argon gas, which is expensive. The present paper reports experimental results on thermal dissociation of zircon in air plasma medium. Process simulation for 'inflight' dissociation of zircon in air plasma medium is also presented. The experimental system consists of a central hollow graphite electrode, which acts as the cathode and a graphite anode. The material to be processed is fed centrally through the cathode. The unique feature of the system is that it uses air as the working gas to generate the thermal plasma. The system has been used to study in-flight dissociation of zircon in the thermal plasma jet. Dissociation was carried out over 10-25 kW power range. Results of the study indicate that complete dissociation of zircon to ZrO{sub 2} and silica could be accomplished at 25 kW in air plasma.

  13. Inflight dissociation of zircon in air plasma

    International Nuclear Information System (INIS)

    Yugeswaran, S; Selvarajan, V; Ananthapadmanabhan, P V; Thiyagarajan, T K; Nair, Janardhanan

    2010-01-01

    Thermal dissociation of zircon can be conveniently carried out in a plasma reactor, which is characterized by high temperature, high energy density and high quench rate. Zirconia is recovered from this partially dissociated zircon by alkali leaching. Dissociation of zircon has been conventionally carried out in argon gas, which is expensive. The present paper reports experimental results on thermal dissociation of zircon in air plasma medium. Process simulation for 'inflight' dissociation of zircon in air plasma medium is also presented. The experimental system consists of a central hollow graphite electrode, which acts as the cathode and a graphite anode. The material to be processed is fed centrally through the cathode. The unique feature of the system is that it uses air as the working gas to generate the thermal plasma. The system has been used to study in-flight dissociation of zircon in the thermal plasma jet. Dissociation was carried out over 10-25 kW power range. Results of the study indicate that complete dissociation of zircon to ZrO 2 and silica could be accomplished at 25 kW in air plasma.

  14. Coulomb dissociation of N-20,N-21

    NARCIS (Netherlands)

    Roeder, Marko; Adachi, Tatsuya; Aksyutina, Yulia; Alcantara, Juan; Altstadt, Sebastian; Alvarez-Pol, Hector; Ashwood, Nicholas; Atar, Leyla; Aumann, Thomas; Avdeichikov, Vladimir; Barr, M.; Beceiro, Saul; Bemmerer, Daniel; Benlliure, Jose; Bertulani, Carlos; Boretzky, Konstanze; Borge, Maria J. G.; Burgunder, G.; Caamano, Manuel; Caesar, Christoph; Casarejos, Enrique; Catford, Wilton; Cederkall, Joakim; Chakraborty, S.; Chartier, Marielle; Chulkov, Leonid; Cortina-Gil, Dolores; Crespo, Raquel; Pramanik, Ushasi Datta; Diaz-Fernandez, Paloma; Dillmann, Iris; Elekes, Zoltan; Enders, Joachim; Ershova, Olga; Estrade, A.; Farinon, F.; Fraile, Luis M.; Freer, Martin; Freudenberger, M.; Fynbo, Hans; Galaviz, Daniel; Geissel, Hans; Gernhaeuser, Roman; Goebel, Kathrin; Kalantar-Nayestanaki, Nasser; Najafi, Mohammad Ali; Rigollet, Catherine; Stoica, V.; Streicher, Branislav; Van de Walle, J.

    2016-01-01

    Neutron-rich light nuclei and their reactions play an important role in the creation of chemical elements. Here, data from a Coulomb dissociation experiment on N-20,N-21 are reported. Relativistic N-20,N-21 ions impinged on a lead target and the Coulomb dissociation cross section was determined in a

  15. Dissociative depression among women in the community.

    Science.gov (United States)

    Sar, Vedat; Akyüz, Gamze; Oztürk, Erdinç; Alioğlu, Firdevs

    2013-01-01

    This study screened the prevalence and correlates of dissociative disorders among depressive women in the general population. The Dissociative Disorders Interview Schedule and the posttraumatic stress disorder (PTSD) and borderline personality disorder sections of the Structured Clinical Interview for DSM-IV were administered to 628 women in 500 homes. The prevalence of current major depressive episode was 10.0%. Of the women, 26 (40.6%) had the lifetime diagnosis of a DSM-IV, dissociative disorder, yielding a prevalence of 4.1% for dissociative depression. This group was younger (mean age = 30.7 years) than the nondissociative depression women (mean age = 39.6 years). There was no difference between the 2 groups on comorbid somatization disorder, PTSD, or borderline personality disorder. Besides suicide attempts, the dissociative group was characterized by secondary features of dissociative identity disorder; Schneiderian symptoms; borderline personality disorder criteria; and extrasensory perceptions, including possession experiences. They reported suicidality, thoughts of guilt and worthlessness, diminished concentration and indecisiveness, and appetite and weight changes more frequently than the nondissociative group. Early cessation of school education and childhood sexual abuse were frequently reported by the dissociative depression group. With its distinct features, the concept of dissociative depression may facilitate understanding of treatment resistance in, development of better psychotherapy strategies for, and new thinking on the neurobiology and pharmacotherapy of depressive disorders.

  16. Biofortification of lettuce (Lactuca sativa L.) with iodine: The effect of iodine form and concentration in the nutrient solution on growth, development and iodine uptake of lettuce grown in water culture

    NARCIS (Netherlands)

    Voogt, W.; Holwerda, H.T.; Khodabaks, M.R.

    2010-01-01

    BACKGROUND: Iodine is an essential trace element for humans. Two billion individuals have insufficient iodine intake. Biofortification of vegetables with iodine offers an excellent opportunity to increase iodine intake by humans. The main aim was to study the effect of iodine form and concentration

  17. Iodine release from sodium pool combustion

    International Nuclear Information System (INIS)

    Sagawa, N.; Fukushima, Y.; Yokota, N.; Akagane, K.; Mochizuki, K.

    1979-01-01

    Iodine release associated with sodium pool combustion was determined by heating 20 gr sodium containing sodium iodide, which was labelled with 131 I and dissolved in the sodium in concentration of 1∼1,000 ppm, to burn on a nickel crucible in conditioned atmosphere in a closed vessel of 0.4 m 3 . Oxygen concentration was changed in 5∼21% and humidity in 0∼89% by mixing nitrogen gas and air. Combustion products were trapped by a Maypack filter composed of particle filters, copper screens and activated charcoal beds and by a glass beads pack cooled by liquid argon. Iodine collected on these filter elements was determined by radio-gas chromatography. When the sodium sample burned in the atmosphere of air at room temperature, the release fractions observed were 6∼33% for sodium and 1∼20% for iodine added in the sodium. The release iodine was present in aerosol at a ratio of 98%, and the remainder in the gas form. The release fraction of iodine trended to decrease as oxygen concentration and humidity in the atmosphere increased. No organic iodide was detected in the combustion products. (author)

  18. Contamination of pasture by iodine 131

    International Nuclear Information System (INIS)

    Angeletti, Livio

    1980-08-01

    The reassessment of the experimental data on the transfer of iodine to aerial parts of rye-gras leads to the following significant findings: 1 - Water content of herbage depending markedly on time and location, the contamination of the vegetals has to be expressed on a dry weight basis. 2 - The value of the geometrical mean of the deposition velocity of iodine vapour as derived from 19 experiments carried out over 4 years is 0.76 cm/s. This value agrees very well with the value of V(d)=0.80 obtained in the USA during experiments comparable as to the number of tests and their duration. Consequently we propose a value of V(d)=0.76 cm/s for the evaluation of pasture land contamination by iodine resulting from routine releases. For accidental releases, however, we propose a value of V(d)=2 cm/s, which was the upper limit in about 90% of our experimental results. 3 - The analysis of data on wet deposition of iodine on the aerial parts of rye-grass shows that the initial retention when expressed as percent of the total deposit decreases with aspersion intensities. If expressed as retention factor, the initial retention is constant, for all aspersion intensities. The average initial iodine retention being lower by a factor of 2.3 than water retention the value of the latter will therefore be the upper limit for this radionuclide [fr

  19. Seaweed tablet: a natural source of iodine

    International Nuclear Information System (INIS)

    Briones, Annabelle V.; Ambal, Wilhelmina O.; Monroyo, Evangelina C.; Bonifacio, Teresita S.; Sison, Fe M.

    1997-01-01

    Species of seaweeds namely: Halymenia durvillaei, Laurencia flexilis and Sargassum gigantifolium were processed into dried form and formulated as tablet. Prior to tablet formulation, the seaweeds were assayed for iodine and trace elements. The seaweeds that exhibited significance values of iodine and trace elements were further analyzed for the presence of heavy metals followed by acute oral toxicity test (LD 50 ). Among the seaweeds evaluated, H. durvilaei was found to contain high level of iodine (0.255% w/w) and magnesium (1.65% w/w) with sufficient amount of zinc (25.69 ppm) and phosporous (11.68 ppm). Analysis of heavy metals showed minute amount of mercury (0.0055 ppm), cadmium (0.67 ppm) and lead (1.80 ppm). The median lethal dose (LD 50 ) of H. durvillaei administered orally in Swiss male mice is 119.1489 ± 4.9873 g/kg. Tablet formulation was based on the U.S. recommended daily allowance of 0.15 mg. of iodine per adult and children. The final product was comparable to imported Kelp pills (available in the local market) in terms of physical properties and iodine content. (Author)

  20. Coverage-dependent adsorption and desorption of oxygen on Pd(100)

    Energy Technology Data Exchange (ETDEWEB)

    Dunnen, Angela den; Jacobse, Leon; Wiegman, Sandra; Juurlink, Ludo B. F., E-mail: l.juurlink@chem.leidenuniv.nl [Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, P.O. Box 9502, 2300 RA Leiden (Netherlands); Berg, Otto T. [Department of Chemistry, California State University Fresno, 2555 E. San Ramon Ave., Fresno, California 93740 (United States)

    2016-06-28

    We have studied the adsorption and desorption of O{sub 2} on Pd(100) by supersonic molecular beam techniques and thermal desorption spectroscopy. Adsorption measurements on the bare surface confirm that O{sub 2} initially dissociates for all kinetic energies between 56 and 380 meV and surface temperatures between 100 and 600 K via a direct mechanism. At and below 150 K, continued adsorption leads to a combined O/O{sub 2} overlayer. Dissociation of molecularly bound O{sub 2} during a subsequent temperature ramp leads to unexpected high atomic oxygen coverages, which are also obtained at high incident energy and high surface temperature. At intermediate temperatures and energies, these high final coverages are not obtained. Our results show that kinetic energy of the gas phase reactant and reaction energy dissipated during O{sub 2} dissociation on the cold surface both enable activated nucleation of high-coverage surface structures. We suggest that excitation of local substrate phonons may play a crucial role in oxygen dissociation at any coverage.