Interaction of rare earth iodides with alkali metal iodides

International Nuclear Information System (INIS)

Krokhina, A.G.; Andrachnikova, A.P.; Strekachinskij, A.B.; Krokhin, V.A.

1980-01-01

The interaction in HoI 3 -NaI, HoI 3 -CsI, TmI 3 -CsI, ScI 3 -NdI, Sc 3 -KI, ScI 3 -RbI systems was studied by the method of differential thermal and X-ray phase analysis. According to the results of the differential thermal analysis, HoI 3 -NaI and ScI 3 -NaI systems were classed with the eutectic type. However, the X-ray phase analysis revealed the presence of a new phase in the solid state of alloys containing approximately 75 mol% NaI. One chemical compound (K 3 Sc-I 6 ) was found in the ScI 3 -KI system and two chemical compounds of Me 3 LnI 6 and Me 3 Ln 2 I 9 (Me-Cs, Rb; Ln-Ho, Tm, Sc) type were found in each of HoI 3 -CsI, TmI 3 -CsI, ScI 3 -RbI systems

The immobilisation of nuclear waste materials containing different alkali elements into single-phase NZP based ceramics

International Nuclear Information System (INIS)

Pet'kov, V.I.; Orlova, A.I.; Trubach, I.G.; Demarin, T.; Kurazhkovskaya, V.S.

2002-01-01

The NZP matrix, which is based on NaZr 2 (PO 4 ) 3 , is a viable candidate for nuclear waste immobilisation. We examined the possibilities of incorporating of alkali elements into the NZP host structure, investigated the conditions of the crystalline solution formation, and determined the regions of the NZP structure compositional stability for a series of complex orthophosphates of titanium or zirconium and alkali elements A m-x A' x M 2-(m-1)/4 (PO 4 ) 3 with m = 1, 3, or 5 and 0 ≤ x ≤ m, where A and A' are mutually different alkali elements and M is Ti or Zr. The phosphates containing Li-Na, Li-K, Li-Rb, Li-Cs, Na-K, Na-Rb, Na-Cs, K-Rb, K-Cs and Rb-Cs pairs were prepared and studied by X-ray powder analysis, IR spectroscopy, simultaneous DTA-TG measurements and electron microprobe analyses. In the systems studied, wide ranges of crystalline phosphate solutions with tailored alkali metal substitutions were formed owing to the large number of sites available for substitution and high degree of flexibility in the NZP structure. It was found that introduction of the less expensive and lighter Ti in the host phase in place of the commonly used Zr permits cheaper ceramics, having in some cases larger alkali element contents, to be obtained. The phases containing alkali metals can be formed, for instance, during phosphate solidification of molten alkali chlorides with radioactive nuclides from the pyroelectrochemical technologies of nuclear fuel recycling

High-pressure phase transition of alkali metal-transition metal deuteride Li2PdD2

Science.gov (United States)

Yao, Yansun; Stavrou, Elissaios; Goncharov, Alexander F.; Majumdar, Arnab; Wang, Hui; Prakapenka, Vitali B.; Epshteyn, Albert; Purdy, Andrew P.

2017-06-01

A combined theoretical and experimental study of lithium palladium deuteride (Li2PdD2) subjected to pressures up to 50 GPa reveals one structural phase transition near 10 GPa, detected by synchrotron powder x-ray diffraction, and metadynamics simulations. The ambient-pressure tetragonal phase of Li2PdD2 transforms into a monoclinic C2/m phase that is distinct from all known structures of alkali metal-transition metal hydrides/deuterides. The structure of the high-pressure phase was characterized using ab initio computational techniques and from refinement of the powder x-ray diffraction data. In the high-pressure phase, the PdD2 complexes lose molecular integrity and are fused to extended [PdD2]∞ chains. The discovered phase transition and new structure are relevant to the possible hydrogen storage application of Li2PdD2 and alkali metal-transition metal hydrides in general.

Secondary cell with orthorhombic alkali metal/manganese oxide phase active cathode material

Science.gov (United States)

Doeff, Marca M.; Peng, Marcus Y.; Ma, Yanping; Visco, Steven J.; DeJonghe, Lutgard C.

1996-01-01

An alkali metal manganese oxide secondary cell is disclosed which can provide a high rate of discharge, good cycling capabilities, good stability of the cathode material, high specific energy (energy per unit of weight) and high energy density (energy per unit volume). The active material in the anode is an alkali metal and the active material in the cathode comprises an orthorhombic alkali metal manganese oxide which undergoes intercalation and deintercalation without a change in phase, resulting in a substantially linear change in voltage with change in the state of charge of the cell. The active material in the cathode is an orthorhombic structure having the formula M.sub.x Z.sub.y Mn.sub.(1-y) O.sub.2, where M is an alkali metal; Z is a metal capable of substituting for manganese in the orthorhombic structure such as iron, cobalt or titanium; x ranges from about 0.2 in the fully charged state to about 0.75 in the fully discharged state, and y ranges from 0 to 60 atomic %. Preferably, the cell is constructed with a solid electrolyte, but a liquid or gelatinous electrolyte may also be used in the cell.

Chloride, bromide and iodide scintillators with europium doping

Science.gov (United States)

Zhuravleva, Mariya; Yang, Kan

2014-08-26

A halide scintillator material is disclosed where the halide may comprise chloride, bromide or iodide. The material is single-crystalline and has a composition of the general formula ABX.sub.3 where A is an alkali, B is an alkali earth and X is a halide which general composition was investigated. In particular, crystals of the formula ACa.sub.1-yEu.sub.yI.sub.3 where A=K, Rb and Cs were formed as well as crystals of the formula CsA.sub.1-yEu.sub.yX.sub.3 (where A=Ca, Sr, Ba, or a combination thereof and X=Cl, Br or I or a combination thereof) with divalent Europium doping where 0.ltoreq.y.ltoreq.1, and more particularly Eu doping has been studied at one to ten mol %. The disclosed scintillator materials are suitable for making scintillation detectors used in applications such as medical imaging and homeland security.

Gas-phase pesticide measurement using iodide ionization time-of-flight mass spectrometry

Directory of Open Access Journals (Sweden)

T. Murschell

2017-06-01

Full Text Available Volatilization and subsequent processing in the atmosphere are an important environmental pathway for the transport and chemical fate of pesticides. However, these processes remain a particularly poorly understood component of pesticide lifecycles due to analytical challenges in measuring pesticides in the atmosphere. Most pesticide measurements require long (hours to days sampling times coupled with offline analysis, inhibiting observation of meteorologically driven events or investigation of rapid oxidation chemistry. Here, we present chemical ionization time-of-flight mass spectrometry with iodide reagent ions as a fast and sensitive measurement of four current-use pesticides. These semi-volatile pesticides were calibrated with injections of solutions onto a filter and subsequently volatilized to generate gas-phase analytes. Trifluralin and atrazine are detected as iodide–molecule adducts, while permethrin and metolachlor are detected as adducts between iodide and fragments of the parent analyte molecule. Limits of detection (1 s are 0.37, 0.67, 0.56, and 1.1 µg m−3 for gas-phase trifluralin, metolachlor, atrazine, and permethrin, respectively. The sensitivities of trifluralin and metolachlor depend on relative humidity, changing as much as 70 and 59, respectively, as relative humidity of the sample air varies from 0 to 80 %. This measurement approach is thus appropriate for laboratory experiments and potentially near-source field measurements.

Methyl Iodide Decomposition at BWR Conditions

International Nuclear Information System (INIS)

Pop, Mike; Bell, Merl

2012-09-01

Based on favourable results from short-term testing of methanol addition to an operating BWR plant, AREVA has performed numerous studies in support of necessary Engineering and Plant Safety Evaluations prior to extended injection of methanol. The current paper presents data from a study intended to provide further understanding of the decomposition of methyl iodide as it affects the assessment of methyl iodide formation with the application of methanol at BWR Plants. This paper describes the results of the decomposition testing under UV-C light at laboratory conditions and its effect on the subject methyl iodide production evaluation. The study as to the formation and decomposition of methyl iodide as it is effected by methanol addition is one phase of a larger AREVA effort to provide a generic plant Safety Evaluation prior to long-term methanol injection to an operating BWR. Other testing phases have investigated the compatibility of methanol with fuel construction materials, plant structural materials, plant consumable materials (i.e. elastomers and coatings), and ion exchange resins. Methyl iodide is known to be very unstable, typically preserved with copper metal or other stabilizing materials when produced and stored. It is even more unstable when exposed to light, heat, radiation, and water. Additionally, it is known that methyl iodide will decompose radiolytically, and that this effect may be simulated using ultra-violet radiation (UV-C) [2]. In the tests described in this paper, the use of a UV-C light source provides activation energy for the formation of methyl iodide. Thus is similar to the effect expected from Cherenkov radiation present in a reactor core after shutdown. Based on the testing described in this paper, it is concluded that injection of methanol at concentrations below 2.5 ppm in BWR applications to mitigate IGSCC of internals is inconsequential to the accident conditions postulated in the FSAR as they are related to methyl iodide formation

Production of Molecular Iodine and Tri-iodide in the Frozen Solution of Iodide: Implication for Polar Atmosphere.

Science.gov (United States)

Kim, Kitae; Yabushita, Akihiro; Okumura, Masanori; Saiz-Lopez, Alfonso; Cuevas, Carlos A; Blaszczak-Boxe, Christopher S; Min, Dae Wi; Yoon, Ho-Il; Choi, Wonyong

2016-02-02

The chemistry of reactive halogens in the polar atmosphere plays important roles in ozone and mercury depletion events, oxidizing capacity, and dimethylsulfide oxidation to form cloud-condensation nuclei. Among halogen species, the sources and emission mechanisms of inorganic iodine compounds in the polar boundary layer remain unknown. Here, we demonstrate that the production of tri-iodide (I3(-)) via iodide oxidation, which is negligible in aqueous solution, is significantly accelerated in frozen solution, both in the presence and the absence of solar irradiation. Field experiments carried out in the Antarctic region (King George Island, 62°13'S, 58°47'W) also showed that the generation of tri-iodide via solar photo-oxidation was enhanced when iodide was added to various ice media. The emission of gaseous I2 from the irradiated frozen solution of iodide to the gas phase was detected by using cavity ring-down spectroscopy, which was observed both in the frozen state at 253 K and after thawing the ice at 298 K. The accelerated (photo-)oxidation of iodide and the subsequent formation of tri-iodide and I2 in ice appear to be related with the freeze concentration of iodide and dissolved O2 trapped in the ice crystal grain boundaries. We propose that an accelerated abiotic transformation of iodide to gaseous I2 in ice media provides a previously unrecognized formation pathway of active iodine species in the polar atmosphere.

Infrared multiple photon dissociation action spectroscopy of alkali metal cation-cyclen complexes: Effects of alkali metal cation size on gas-phase conformation

NARCIS (Netherlands)

Austin, C.A.; Chen, Y.; Kaczan, C.M.; Berden, G.; Oomens, J.; Rodgers, M.T.

2013-01-01

The gas-phase structures of alkali metal cationized complexes of cyclen (1,4,7,10-tetraazacyclododecane) are examined via infrared multiple photon dissociation (IRMPD) action spectroscopy and electronic structure theory calculations. The measured IRMPD action spectra of four M+(cyclen) complexes are

Inorganic alkali lead iodide semiconducting APbI3 (A = Li, Na, K, Cs and NH4PbI3 films prepared from solution: Structure, morphology, and electronic structure

Directory of Open Access Journals (Sweden)

Eric Mankel

2016-06-01

Full Text Available APbI3 alkali lead iodides were prepared from aqueous (A= Na, Cs, ammonium NH4+, and methyl­ammonium CH3NH3+ and acetone (A= Li, K solutions by a self-organization low temperature process. Diffraction analysis revealed that the methylammonium-containing system (MAPbI3 crystallizes into a tetragonal perovskite structure, whereas the alkali and NH4+ systems adopt orthorhombic structures. Morphological inspection confirmed the influence of the cation on the growth mechanism: for A = Cs and NH4+, needle-like crystallites with lengths up to 3–4 mm; for A = K, thin stripes with lengths up to 5–6 mm; and for A = MA+, dodecahedral crystallites were observed. For A = Li and Na, the APbI3 systems typically resulted in polycrystalline aggregates. Optical absorption measurements demonstrated large energy band gaps for the alkali and ammonium systems with values between 2.19 and 2.40 eV. For electronic and chemical characterization by photoelectron spectroscopy, the as-prepared powders were dissolved in di-methylformamide and re-crystallized as thin films on F:SnO2 substrates by spin-coating. The binding energy differences between Pb4f and I3d core levels are highly similar in the investigated systems and close to the value measured for PbI2, indicating similar relative partial charges and formal oxidation states. The binding energies of the alkali ions are in accordance with oxidation state +1. The X-ray excited valence band spectra of the investigated APbI3 systems exhibited similar line shapes in the region between the valence band maximum and 4.5 eV higher binding energy due to common PbI6 octahedra which dominate the electronic structure. While the ionization energy values are quite similar (6.15 ± 0.25 eV, the Fermi-level positions of the unintentionally doped materials vary for different cations and different batches of the same material, which indicates that the position of the Fermi level can be influenced by changing the process parameters.

Rapid, specific determination of iodine and iodide by combined solid-phase extraction/diffuse reflectance spectroscopy

Science.gov (United States)

Arena, Matteo P.; Porter, Marc D.; Fritz, James S.

2002-01-01

A new, rapid methodology for trace analysis using solid-phase extraction is described. The two-step methodology is based on the concentration of an analyte onto a membrane disk and on the determination by diffuse reflectance spectroscopy of the amount of analyte extracted on the disk surface. This method, which is adaptable to a wide range of analytes, has been used for monitoring ppm levels of iodine and iodide in spacecraft water. Iodine is used as a biocide in spacecraft water. For these determinations, a water sample is passed through a membrane disk by means of a 10-mL syringe that is attached to a disk holder assembly. The disk, which is a polystyrene-divinylbenzene composite, is impregnated with poly(vinylpyrrolidone) (PVP), which exhaustively concentrates iodine as a yellow iodine-PVP complex. The amount of concentrated iodine is then determined in only 2 s by using a hand-held diffuse reflectance spectrometer by comparing the result with a calibration curve based on the Kubelka-Munk function. The same general procedure can be used to determine iodide levels after its facile and exhaustive oxidation to iodine by peroxymonosulfate (i.e., Oxone reagent). For samples containing both analytes, a two-step procedure can be used in which the iodide concentration is calculated from the difference in iodine levels before and after treatment of the sample with peroxymonosulfate. With this methodology, iodine and iodide levels in the 0.1-5.0 ppm range can be determined with a total workup time of approximately 60 s with a RSD of approximately 6%.

First-principles simulations on the new hybrid phases of germanene with alkali metal atoms coverage

Energy Technology Data Exchange (ETDEWEB)

Yuan, Jianmei [Hunan Key Laboratory for Computation and Simulation in Science and Engineering, School of Mathematics and Computational Science, Xiangtan University, Hunan 411105 (China); Tang, Chan; Zhong, Jianxin [Hunan Key Laboratory for Micro-Nano Energy Materials and Devices, School of Physics and Optoelectronic Engineering, Xiangtan University, Hunan 411105 (China); Mao, Yuliang, E-mail: ylmao@xtu.edu.cn [Hunan Key Laboratory for Micro-Nano Energy Materials and Devices, School of Physics and Optoelectronic Engineering, Xiangtan University, Hunan 411105 (China)

2016-01-01

Graphical abstract: - Highlights: • The predicted new phase of complete lithiated germanene is more favorable to form than germanane. • Besides ionic interactions, covalent component in some extent leads the complete lithiated germanene into a semiconductor. • 2D phases of Ge{sub 2}X{sub 1} (X = Li, Na, K) are metallic with weak polarization. • Half-lithiated germanene exhibits local magnetic moments on the Ge atoms neighbored with Li adatoms. - Abstract: We present first-principles calculations of a new type hybrid phases composed by buckled germanene with saturated or half-saturated alkali metal atoms adsorption. Our energetics and electronic structure analysis suggests that adsorbed alkali metal atoms (Li, Na, K) can be used as covered adatoms to synthesize germanene-based new phases in two dimensional. The predicted new phases of Ge{sub 2}X{sub 2} and Ge{sub 2}X{sub 1} (X = Li, Na, K) relative to the single germanene sheet could exist at room temperature. The formation energy of Ge{sub 2}Li{sub 2} configuration obtained from complete lithiation is even more favorable than that of germanane. Charge transfer is significant between the alkali metal atoms and Ge, indicating the ionic interactions between them. Furthermore, our charge density analysis indicates that covalent component in some extent exists in Ge{sub 2}X{sub 2} and Ge{sub 2}X{sub 1} (X = Li, Na, K) 2D phases, which even leads the complete lithiated germanene into a semiconductor with an energy gap of 0.14 eV. We report that 2D phases of Ge{sub 2}X{sub 1} (X = Li, Na, K) are metallic with weak polarization on the Fermi level and in unoccupied states. It is found that half-lithiated germanene exhibits local magnetic moments of 0.48 μ{sub B} on the Ge atoms neighbored with Li adatoms.

Thermodynamic modelling of alkali-activated slag cements

International Nuclear Information System (INIS)

Myers, Rupert J.; Lothenbach, Barbara; Bernal, Susan A.; Provis, John L.

2015-01-01

Highlights: • A thermodynamic modelling analysis of alkali-activated slag cements is presented. • Thermodynamic database describes zeolites, alkali carbonates, C–(N–)A–S–H gel. • Updated thermodynamic model for Mg–Al layered double hydroxides. • Description of phase assemblages in Na 2 SiO 3 - and Na 2 CO 3 -activated slag cements. • Phase diagrams for NaOH-activated and Na 2 SiO 3 -activated slag cements are simulated. - Abstract: This paper presents a thermodynamic modelling analysis of alkali-activated slag-based cements, which are high performance and potentially low-CO 2 binders relative to Portland cement. The thermodynamic database used here contains a calcium (alkali) aluminosilicate hydrate ideal solid solution model (CNASH-ss), alkali carbonate and zeolite phases, and an ideal solid solution model for a hydrotalcite-like Mg–Al layered double hydroxide phase. Simulated phase diagrams for NaOH- and Na 2 SiO 3 -activated slag-based cements demonstrate the high stability of zeolites and other solid phases in these materials. Thermodynamic modelling provides a good description of the chemical compositions and types of phases formed in Na 2 SiO 3 -activated slag cements over the most relevant bulk chemical composition range for these cements, and the simulated volumetric properties of the cement paste are consistent with previously measured and estimated values. Experimentally determined and simulated solid phase assemblages for Na 2 CO 3 -activated slag cements were also found to be in good agreement. These results can be used to design the chemistry of alkali-activated slag-based cements, to further promote the uptake of this technology and valorisation of metallurgical slags

Thermodynamic and kinetic analysis of solid-phase interaction of alkali metal carbonates with arsenic pentoxide

International Nuclear Information System (INIS)

Pashinkin, A.S.; Buketov, E.A.; Isabaeva, S.M.; Kasenov, B.K.

1985-01-01

The thermodynamic analysis of solid-phase reactions of alkali metal carbonates with arsenic pentoxide showing the possibility of formation of all arsenates at a higher than the room temperature is performed. Energetically most advantageous is formation of meta-arsenates. It is shown that temperature increase favours the reaction process. By Gibbs standard energy decrease the reactions form the Li>Na>K>Rb>Cs series. On the base of calculation data linear dependence of Gibbs standard energy in reactions on the atomic number of alkali metalis established. By the continuous weighing method the kinetics of interaction of alkali metal carbonates with arsenic pentoxide under isothermal conditions in the 450-500 deg C range is studied. Studies is the dependence of apparent energy of interaction of carbonates wih As 2 0 5 an atomic parameters of al

Radiolytic formation of organic iodides from organic compounds released from ripolin paint

International Nuclear Information System (INIS)

Attia, S.; Evans, G.J.

2002-01-01

The impact of a serious nuclear reactor accident is governed to a large extent by the possible release of airborne organic iodides to the environment. This research examines the identification and behavior of organic iodides formed in the containment due to the release of organic compounds from Ripolin paint, into the aqueous phase, following a nuclear reactor accident. A bench scale apparatus installed in the irradiation chamber of a Gammacell was used to analyze the formation of organic iodides. Iodo-organics, transferred to the gas phase above irradiated aqueous samples, were analyzed using a Thermal Desorption method coupled with gas chromatography and mass spectrometry. Detailed studies of the identity of the organic compounds released and the organic iodides formed were conducted. The effects of parameters such as irradiation dose were also examined. All the organic iodides formed, under radiolytic conditions, were identified as iodo-alkanes. The organic compounds that were released from the Ripolin paint, such as methyl isobutyl ketone, were found to decompose, by a series of reactions, to produce the organic iodides. The precursor organic compounds and the organic iodides formed were observed to consist of the same alkyl group. These results indicate that organic compounds released from surface paints directly influence the formation of radiolytic organic iodide. (author)

Formamidinium iodide: crystal structure and phase transitions

Directory of Open Access Journals (Sweden)

Andrey A. Petrov

2017-04-01

Full Text Available At a temperature of 100 K, CH5N2+·I− (I, crystallizes in the monoclinic space group P21/c. The formamidinium cation adopts a planar symmetrical structure [the r.m.s. deviation is 0.002 Å, and the C—N bond lengths are 1.301 (7 and 1.309 (8 Å]. The iodide anion does not lie within the cation plane, but deviates from it by 0.643 (10 Å. The cation and anion of I form a tight ionic pair by a strong N—H...I hydrogen bond. In the crystal of I, the tight ionic pairs form hydrogen-bonded zigzag-like chains propagating toward [20-1] via strong N—H...I hydrogen bonds. The hydrogen-bonded chains are further packed in stacks along [100]. The thermal behaviour of I was studied by different physicochemical methods (thermogravimetry, differential scanning calorimetry and powder diffraction. Differential scanning calorimetry revealed three narrow endothermic peaks at 346, 387 and 525 K, and one broad endothermic peak at ∼605 K. The first and second peaks are related to solid–solid phase transitions, while the third and fourth peaks are attributed to the melting and decomposition of I. The enthalpies of the phase transitions at 346 and 387 K are estimated as 2.60 and 2.75 kJ mol−1, respectively. The X-ray powder diffraction data collected at different temperatures indicate the existence of I as the monoclinic (100–346 K, orthorhombic (346–387 K and cubic (387–525 K polymorphic modifications.

Upgrading platform using alkali metals

Science.gov (United States)

Gordon, John Howard

2014-09-09

A process for removing sulfur, nitrogen or metals from an oil feedstock (such as heavy oil, bitumen, shale oil, etc.) The method involves reacting the oil feedstock with an alkali metal and a radical capping substance. The alkali metal reacts with the metal, sulfur or nitrogen content to form one or more inorganic products and the radical capping substance reacts with the carbon and hydrogen content to form a hydrocarbon phase. The inorganic products may then be separated out from the hydrocarbon phase.

Discriminating Properties of Alkali Metal Ions Towards the Constituents of Proteins and Nucleic Acids. Conclusions from Gas-Phase and Theoretical Studies.

Science.gov (United States)

Rodgers, Mary T; Armentrout, Peter B

2016-01-01

Quantitative insight into the structures and thermodynamics of alkali metal cations interacting with biological molecules can be obtained from studies in the gas phase combined with theoretical work. In this chapter, the fundamentals of the experimental and theoretical techniques are first summarized and results for such work on complexes of alkali metal cations with amino acids, small peptides, and nucleobases are reviewed. Periodic trends in how these interactions vary as the alkali metal cations get heavier are highlighted.

Alkali-heat treatment of a low modulus biomedical Ti-27Nb alloy

International Nuclear Information System (INIS)

Zhou, Y; Wang, Y B; Zhang, E W; Cheng, Y; Xiong, X L; Zheng, Y F; Wei, S C

2009-01-01

This study focuses on the surface modification of a near β-type Ti-27 wt.% Nb alloy by alkali-heat treatment. The influence of alkali concentration, alkali-treated time and alkali-treated temperature on the microstructure and constitutional phases of the modified surface is investigated by SEM, XRD and ICP. Immersion experiments in a simulated body fluid (SBF) were carried out to examine the Ca-P phase forming ability of the modified surfaces. The SEM observation and XRD analysis revealed that a sodium titanate layer is formed after alkali-heat treatment. The morphology and Ca-P phase forming of the layer are greatly affected by the surface roughness of the samples, the alkali concentration, the alkali-treated time and alkali-treated temperature. The results of SBF immersion, which are obtained by ICP analysis, indicate that the activated sodium titanate layer prepared by alkali-heat treatment is beneficial to further improving the biocompatibility of the Ti-27 wt.% Nb alloy.

Mercuric Iodide Anticoincidence Shield for Gamma-Ray Spectrometer, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — We propose to utilize a new detector material, polycrystalline mercuric iodide, for background suppression by active anticoincidence shielding in gamma-ray...

Mercuric Iodide Anticoincidence Shield for Gamma-Ray Spectrometer, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — We utilize a new detector material, polycrystalline mercuric iodide, for background suppression by active anticoincidence shielding in gamma-ray spectrometers. Two...

Factors affecting the retention of methyl iodide by iodide-impregnated carbon

International Nuclear Information System (INIS)

Hyder, M.L.; Malstrom, R.A.

1991-01-01

This paper comprises two sets of studies of methyl iodide retention by iodide-impregnated carbon. In the first of these, the retention of the methyl iodide on the carbon surface and its subsequent evolution were observed directly by a technique of combustion and phosphorescence. In the second, the methyl iodide retention in a standard test was compared with surface area measurements and the concentration of unreacted iodine. A correlation among these parameters was identified and characterized. Carbon quality was varied through the selection of used material with differing service histories. Air from the Savannah River Site reactor buildings is vented through carbon beds for control of radioiodine before release to the atmosphere. The carbon used is North American Carbon Co. type GX-176 coconut shell carbon impregnated with 1% triethylenedimaine (TEDA) and 2% potassium iodide by weight. Replacement intervals for the carbon have been as long as thirty months. Analysis of samples withdrawn at much shorter times has shown that the TEDA is lost after a few months, and the performance of the carbon for methyl iodide retention is dependent on the iodide impregnant. Efficient methyl iodide retention is not a requirement for carbon in this service; however, methyl iodide retention as measured by the ASTM Test D3803 (method B) has been found to correlate well with other desirable properties of the carbon such as radiation stability. The studies undertaken here were intended to shed light on the changes taking place in this carbon during long-term service and to provide a basis for simpler measurements of carbon quality

The evolution of hydrogen and iodine by the decomposition of ammonium iodide and hydrogen iodide

International Nuclear Information System (INIS)

Ishikawa, Hiroshi; Nakane, Masanori; Ishii, Eiichi; Uehara, Itsuki; Miyake, Yoshizo

1977-01-01

As a fundamental study on thermochemical production of hydrogen from water, the evolution of hydrogen and iodine from ammonium iodide and hydrogen iodide was investigated. Hydrogen was evolved by the reaction of nickel with ammonium iodide or with hydrogen iodide, and the resulting nickel(II) iodide was decomposed thermally at 600 -- 700 0 C to form nickel. First, the iodination of powdered nickel with ammonium iodide was studied by heating their powder mixture. The maximum yield of hydrogen was obtained at a temperature near 430 0 C. The iodination of powdered nickel with gaseous ammonium iodide or with dry hydrogen iodide gas was also investigated. In this case, coating of nickel particles with a layer of resulting nickel(II) iodide prevented further conversion of nickel and lowered the reaction rate. Such a retardation effect was appreciably lessened by use of carrier. When nickel was supported on such a carrier as ''isolite'', the nickel was converted into nickel(II) iodide easily. In a reaction temperature from 400 to 500 0 C, the rate of reaction between nickel and hydrogen iodide increased slightly with the elevation of the reaction temperature. In the case of ammonium iodide, the reaction rate was higher than that for hydrogen iodide and decreased apparently with the elevation of the reaction temperature, because ammonium iodide decomposed to ammonia and hydrogen iodide. Tests using a fixed bed reactor charged with 8 -- 10 mesh ''isolite''-nickel (30 wt%) were also carried out. The maximum yield of hydrogen was about 80% for ammonium iodide at 430 0 C of reaction temperature and 60% for hydrogen iodide at 500 0 C. (auth.)

Fast iodide-SAD phasing for high-throughput membrane protein structure determination.

Science.gov (United States)

Melnikov, Igor; Polovinkin, Vitaly; Kovalev, Kirill; Gushchin, Ivan; Shevtsov, Mikhail; Shevchenko, Vitaly; Mishin, Alexey; Alekseev, Alexey; Rodriguez-Valera, Francisco; Borshchevskiy, Valentin; Cherezov, Vadim; Leonard, Gordon A; Gordeliy, Valentin; Popov, Alexander

2017-05-01

We describe a fast, easy, and potentially universal method for the de novo solution of the crystal structures of membrane proteins via iodide-single-wavelength anomalous diffraction (I-SAD). The potential universality of the method is based on a common feature of membrane proteins-the availability at the hydrophobic-hydrophilic interface of positively charged amino acid residues with which iodide strongly interacts. We demonstrate the solution using I-SAD of four crystal structures representing different classes of membrane proteins, including a human G protein-coupled receptor (GPCR), and we show that I-SAD can be applied using data collection strategies based on either standard or serial x-ray crystallography techniques.

Binding of chloride and alkalis in Portland cement systems

International Nuclear Information System (INIS)

Nielsen, Erik P.; Herfort, Duncan; Geiker, Mette R.

2005-01-01

A thermodynamic model for describing the binding of chloride and alkalis in hydrated Portland cement pastes has been developed. The model is based on the phase rule, which for cement pastes in aggressive marine environment predicts multivariant conditions, even at constant temperature and pressure. The effect of the chloride and alkalis has been quantified by experiments on cement pastes prepared from white Portland cements containing 4% and 12% C 3 A, and a grey Portland cement containing 7% C 3 A. One weight percent calcite was added to all cements. The pastes prepared at w/s ratio of 0.70 were stored in solutions of different Cl (CaCl 2 ) and Na (NaOH) concentrations. When equilibrium was reached, the mineralogy of the pastes was investigated by EDS analysis on the SEM. A well-defined distribution of chloride was found between the pore solution, the C-S-H phase, and an AFm solid solution phase consisting of Friedel's salt and monocarbonate. Partition coefficients varied as a function of iron and alkali contents. The lower content of alkalis in WPC results in higher chloride contents in the C-S-H phase. High alkali contents result in higher chloride concentrations in the pore solution

Inclusion complexation of tetrabutylammonium iodide by cyclodextrins

Indian Academy of Sciences (India)

Biswajit Datta

Host-guest inclusion complex of an ionic solid (tetrabutyl ammonium iodide) with α- and β- cyclodextrin has been ... tions.2 CDs are cyclic oligomer of α-D-glucose having numerous of ... of locating at the interface of two phases (liquid–liquid.

dl-Alaninium iodide

Directory of Open Access Journals (Sweden)

Kevin Lamberts

2012-06-01

Full Text Available The crystal structure of dl-alanine hydroiodide (1-carboxyethanaminium iodide, C3H8NO2+·I−, is that of an organic salt consisting of N-protonated cations and iodide anions. The compound features homochiral helices of N—H...O hydrogen-bonded cations in the [010] direction; neighbouring chains are related by crystallographic inversion centers and hence show opposite chirality. The iodide counter-anions act as hydrogen-bond acceptors towards H atoms of the ammonium and carboxy groups, and cross-link the chains along [100]. Thus, an overall two-dimensional network is formed in the ab plane. No short contacts occur between iodide anions.

Dynamic iodide trapping by tumor cells expressing the thyroidal sodium iodide symporter

International Nuclear Information System (INIS)

Dingli, David; Bergert, Elizabeth R.; Bajzer, Zeljko; O'Connor, Michael K.; Russell, Stephen J.; Morris, John C.

2004-01-01

The thyroidal sodium iodide symporter (NIS) in combination with various radioactive isotopes has shown promise as a therapeutic gene in various tumor models. Therapy depends on adequate retention of the isotope in the tumor. We hypothesized that in the absence of iodide organification, isotope trapping is a dynamic process either due to slow efflux or re-uptake of the isotope by cells expressing NIS. Iodide efflux is slower in ARH-77 and K-562 cells expressing NIS compared to a thyroid cell line. Isotope retention half times varied linearly with the number of cells expressing NIS. With sufficient NIS expression, iodide efflux is a zero-order process. Efflux kinetics in the presence or absence of perchlorate also supports the hypothesis that iodide re-uptake occurs and contributes to the retention of the isotope in tumor cells. Iodide organification was insignificant. In vivo studies in tumors composed of mixed cell populations confirmed these observations

Alkali Influence on Synthesis of Solid Electrolyte Based on Alkali Nitrate-Alumina

International Nuclear Information System (INIS)

Yustinus Purwamargapratala; Purnama, S.; Purwanto, P.

2008-01-01

Research of solid electrolyte based on alumina with addition of alkali materials of barium nitrate, calcium nitrate, sodium nitrate and lithium nitrate has been done. Aluminium hydroxide and alkali nitrate were mixed in mole ratio of 1 : 1 in water media and pyrolyzed at 300 o C for 1 hour Pyrolysis result were then mixed with alumina in mole ratio of 1 : 1, compacted and heated at 600 o C for 3 hours. To characterize the sample, XRD (X-Ray Diffractometers) and LCR meter (impedance, capacitance, and resistance) were used for analysis the phase and conductivity properties. The result showed formation of alkali-aluminate in which Li-base have the highest room temperature conductivity of 3.1290 x 10 -5 S.cm -1 , while Ba-base have the lowest conductivity of 5.7266 x 10 -8 S.cm -1 . (author)

Calcium silicate hydrate: Crystallisation and alkali sorption

International Nuclear Information System (INIS)

Hong, S.

2000-01-01

Homogeneous single C-S-H gels has been prepared for the investigation of alkali binding potential and crystallisation. A distribution coefficient, R d , was introduced to express the partition of alkali between solid and aqueous phases at 25 deg. C. R d is independent of alkali hydroxide concentration and depends only on Ca:Si ratio over wide ranges of alkali concentration. The trend of numerical values of R d indicates that alkali bonding into the solid improves as its Ca:Si ratio decreases. Reversibility is demonstrated, indicating a possibility of constant R d value of the material. Al has been introduced to form C-A-S-H gels and their alkali sorption properties also determined. Al substituted into C-S-H markedly increases R d , indicating enhancement of alkali binding. However, the dependence of R d on alkali concentration is non-ideal with composition. A two-site model for bonding is presented. Crystallisation both under saturated steam and 1 bar vapour pressure has been investigated. It has been shown that heat treatment by saturated steam causes crystallisation of gels. The principal minerals obtained were (i) C-S-H gel and Ca(OH) 2 at -55 deg. C, (ii) 1.1 nm tobermorite, jennite and afwillite at 85 -130 deg. C, and (iii) xonotlite, foshagite and hillebrandite at 150-180 deg. C. Properties of crystalline C-S-H were also reported for reversible phase transformation, pH conditioning ability, seeding effect and solubility. At 1 bar pressure, crystallisation is slower than in saturated steam due to lower water activity. Tobermorite-like nanodomains develop during reaction at low Ca/Si ratios. In some Ca-rich compositions, Ca(OH) 2 is exsolved and occurs as nano-sized crystallites. (author)

Studies of selected transuranium and lanthanide tri-iodides under pressure using absorption spectrophotometry

International Nuclear Information System (INIS)

Haire, R.G.; Young, J.P.; Peterson, J.R.; Tennessee Univ., Knoxville; Benedict, U.

1987-01-01

The anhydrous tri-iodides of plutonium, americium and curium under pressure have been investigated using absorption spectrophotometry. These initial studies on plutonium and curium tri-iodides together with the published data for americium tri-iodide show that the rhombohedral form of these compounds (BiI 3 -type structure) can be converted to the orthorhombic form (PuBr 3 -type structure) by applying pressure at room temperature. Absorption spectrophotometry can often differentiate between two crystallographic forms of a material and has been used in the present high-pressure studies to monitor the effects of pressure on the tri-iodides. A complication in these studies of the tri-iodides is a significant shift of their absorption edges with pressure from the near UV to the visible spectral region. With curium tri-iodide this shift causes interference with the major f-f absorption peaks and precludes identification by absorption spectrophotometry of the high pressure phase of CmI 3 . (orig.)

Substrate effects on photoluminescence and low temperature phase transition of methylammonium lead iodide hybrid perovskite thin films

Science.gov (United States)

Shojaee, S. A.; Harriman, T. A.; Han, G. S.; Lee, J.-K.; Lucca, D. A.

2017-07-01

We examine the effects of substrates on the low temperature photoluminescence (PL) spectra and phase transition in methylammonium lead iodide hybrid perovskite (CH3NH3PbI3) thin films. Structural characterization at room temperature with X-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy indicated that while the chemical structure of films deposited on glass and quartz was similar, the glass substrate induced strain in the perovskite films and suppressed the grain growth. The luminescence response and phase transition of the perovskite thin films were studied by PL spectroscopy. The induced strain was found to affect both the room temperature and low temperature PL spectra of the hybrid perovskite films. In addition, it was found that the effects of the glass substrate inhibited a tetragonal to orthorhombic phase transition such that it occurred at lower temperatures.

High-Throughput Screening and Quantitative Chemical Ranking for Sodium-Iodide Symporter Inhibitors in ToxCast Phase I Chemical Library.

Science.gov (United States)

Wang, Jun; Hallinger, Daniel R; Murr, Ashley S; Buckalew, Angela R; Simmons, Steven O; Laws, Susan C; Stoker, Tammy E

2018-05-01

Thyroid uptake of iodide via the sodium-iodide symporter (NIS) is the first step in the biosynthesis of thyroid hormones that are critical for health and development in humans and wildlife. Despite having long been a known target of endocrine disrupting chemicals such as perchlorate, information regarding NIS inhibition activity is still unavailable for the vast majority of environmental chemicals. This study applied a previously validated high-throughput approach to screen for NIS inhibitors in the ToxCast phase I library, representing 293 important environmental chemicals. Here 310 blinded samples were screened in a tiered-approach using an initial single-concentration (100 μM) radioactive-iodide uptake (RAIU) assay, followed by 169 samples further evaluated in multi-concentration (0.001 μM-100 μM) testing in parallel RAIU and cell viability assays. A novel chemical ranking system that incorporates multi-concentration RAIU and cytotoxicity responses was also developed as a standardized method for chemical prioritization in current and future screenings. Representative chemical responses and thyroid effects of high-ranking chemicals are further discussed. This study significantly expands current knowledge of NIS inhibition potential in environmental chemicals and provides critical support to U.S. EPA's Endocrine Disruptor Screening Program (EDSP) initiative to expand coverage of thyroid molecular targets, as well as the development of thyroid adverse outcome pathways (AOPs).

The evolution of strength and crystalline phases for alkali-activated ground blast furnace slag and fly ash-based geopolymers

KAUST Repository

Oh, Jae Eun; Monteiro, Paulo J.M.; Jun, Ssang Sun; Choi, Sejin; Clark, Simon M.

2010-01-01

The increase in strength and evolution of crystalline phases in inorganic polymer cement, made by the alkali activation of slag, Class C and Class F fly ashes, was followed using compressive strength test and synchrotron X-ray diffraction. In order

Electronic properties and Compton profiles of silver iodide

Indian Academy of Sciences (India)

We have carried out an extensive study of electronic properties of silver iodide in - and -phases. The theoretical Compton profiles, energy bands, density of states and anisotropies in momentum densities are computed using density functional theories. We have also employed full-potential linearized augmented ...

Barium iodide and strontium iodide crystals andd scintillators implementing the same

Science.gov (United States)

Payne, Stephen A; Cherepy, Nerine J; Hull, Giulia E; Drobshoff, Alexander D; Burger, Arnold

2013-11-12

In one embodiment, a material comprises a crystal comprising strontium iodide providing at least 50,000 photons per MeV. A scintillator radiation detector according to another embodiment includes a scintillator optic comprising europium-doped strontium iodide providing at least 50,000 photons per MeV. A scintillator radiation detector in yet another embodiment includes a scintillator optic comprising SrI.sub.2 and BaI.sub.2, wherein a ratio of SrI.sub.2 to BaI.sub.2 is in a range of between 0:1 A method for manufacturing a crystal suitable for use in a scintillator includes mixing strontium iodide-containing crystals with a source of Eu.sup.2+, heating the mixture above a melting point of the strontium iodide-containing crystals, and cooling the heated mixture near the seed crystal for growing a crystal. Additional materials, systems, and methods are presented.

Potentiometric sensing of iodide using polymeric membranes of microwave stabilized β-AgI

International Nuclear Information System (INIS)

James, Dhanya; Rao, T. Prasada

2012-01-01

Highlights: ► Stable β-phase was obtained by post MW irradiation of AgI precipitate. ► Constructed ISEby dispersing stable β-AgI crystals in polyvinyl chloride. ► Designed iodide ISE exhibited wide linear range and fast response. ► Highly selective with selectivity factors less than 10 −6 . ► Successfully applied to natural waters, table salt and human urine samples. - Abstract: A polymer based heterogeneous ion selective electrode (ISE) membrane was fabricated for the potentiometric sensing of iodide. The sensing element used for the preparation of the ISE membrane was microwave stabilized β-AgI. Because microwave energy was found to be beneficial for causing hysteresis at the phase transition temperature of AgI, an attempt has been made to prepare stable and conductive β-AgI crystals by post microwave irradiation under high pressure. A conventionally precipitated AgI based ISE was also fabricated for comparative studies. The β-AgI based ISE could respond to a wide range of iodide concentrations (1 × 10 −8 to 1 M) within 60 s with a detection limit of 10 nM. The ISE gave stable response to iodide ions in a pH range of 2.0–8.0 and was highly selective in the presence of various interfering ions. The performance of the proposed iodide ISE in the analysis of natural and seawater samples was encouraging, and the determination of iodide in table salt and human urine samples was explained using the developed sensor.

Processes of adsorption/desorption of iodides and cadmium cations onto/from Ag(111

Directory of Open Access Journals (Sweden)

VLADIMIR D. JOVIĆ

2011-02-01

Full Text Available In this work, the adsorption/desorption processes of iodides and cadmium cations in the presence of iodides onto/from Ag(111 were investigated. It was shown that both processes were complex, characterized by several peaks on the cyclic voltammograms (CVs. By PeakFit analysis of the recorded CVs and subsequent fitting of the obtained peaks by the Frumkin adsorption isotherm, the interaction parameter (f and the Gibbs energy of adsorption (DGads for each adsorbed phase were determined. In the case of iodide adsorption, four peaks were characterized by negative values of f, indicating attractive lateral interaction between the adsorbed anions, while two of them possessed value of f < –4, indicating phase transition processes. The adsorption/desorption processes of cadmium cations (underpotential deposition – UPD of cadmium in the presence of iodide anions was characterized by two main peaks, each of them being composed of two or three peaks with negative values of f. By the analysis of charge vs. potential dependences obtained either from the CVs or current transients on potentiostatic pulses, it was concluded that adsorbed iodides did not undergo desorption during the process of Cd UPD, but became replaced by Cd ad-atoms and remained adsorbed on top of a Cd layer and/or in between Cd the ad-atoms.

Parametric Study on the Organic Iodide Behavior during a Severe Accident

International Nuclear Information System (INIS)

Ryu, Myung Hyun; Kim, Han Chul; Kim, Do Sam

2011-01-01

Iodine is a major contributor to the potential health risk for the public following a severe accident from a nuclear power plant. Most of metal-iodides, the major form of iodine that enters the containment, can be readily dissolved in the sump water and result in iodide ions. These will be oxidized to form volatile I 2 through a large number of reactions such as radiolysis and hydrolysis. The organic radicals, made from organics such as paint in the sump water, react with iodine to produce organic iodides. Volatile iodine moves from the sump water to the atmosphere mainly by diffusion and natural convection, and react with surfaces and air radiolysis products (ARPs). Painted surfaces act as a sink for I 2 and as a source for organic iodides through adsorption and desorption. ARPs react with I 2 to form iodine oxides, which leads to the decrease of I 2 and organic iodides. Among the large number of iodine species, organic iodides have been extensively studied recently due to their volatility and very low retention. Qualified tools for modeling these phenomena have been developed and validated by several experiments such as EPICUR, PARIS and OECD-BIP. While mechanistic codes model a large number of reactions and species, semiempirical codes such as IODE or IMOD treat major ones. KINS developed a simple iodine model, RAIM (Radio-active iodine chemistry model), based on the IMOD methodology in order to deal with organic iodides conveniently, coupling with an integrated severe-accident analysis code. There are a number of mechanisms that affect the behavior of organic iodides. In this study, effects of pH of the aqueous phase, temperature, radiation dose rate, surface area of organic paints, initial iodine loads that are known to be important to organic iodide formation were studied analytically with RAIM, and also theoretically

Parametric Study on the Organic Iodide Behavior during a Severe Accident

Energy Technology Data Exchange (ETDEWEB)

Ryu, Myung Hyun; Kim, Han Chul; Kim, Do Sam [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

2011-10-15

Iodine is a major contributor to the potential health risk for the public following a severe accident from a nuclear power plant. Most of metal-iodides, the major form of iodine that enters the containment, can be readily dissolved in the sump water and result in iodide ions. These will be oxidized to form volatile I{sub 2} through a large number of reactions such as radiolysis and hydrolysis. The organic radicals, made from organics such as paint in the sump water, react with iodine to produce organic iodides. Volatile iodine moves from the sump water to the atmosphere mainly by diffusion and natural convection, and react with surfaces and air radiolysis products (ARPs). Painted surfaces act as a sink for I{sub 2} and as a source for organic iodides through adsorption and desorption. ARPs react with I{sub 2} to form iodine oxides, which leads to the decrease of I{sub 2} and organic iodides. Among the large number of iodine species, organic iodides have been extensively studied recently due to their volatility and very low retention. Qualified tools for modeling these phenomena have been developed and validated by several experiments such as EPICUR, PARIS and OECD-BIP. While mechanistic codes model a large number of reactions and species, semiempirical codes such as IODE or IMOD treat major ones. KINS developed a simple iodine model, RAIM (Radio-active iodine chemistry model), based on the IMOD methodology in order to deal with organic iodides conveniently, coupling with an integrated severe-accident analysis code. There are a number of mechanisms that affect the behavior of organic iodides. In this study, effects of pH of the aqueous phase, temperature, radiation dose rate, surface area of organic paints, initial iodine loads that are known to be important to organic iodide formation were studied analytically with RAIM, and also theoretically

Utilization of Mineral Wools as Alkali-Activated Material Precursor

Directory of Open Access Journals (Sweden)

Juho Yliniemi

2016-04-01

Full Text Available Mineral wools are the most common insulation materials in buildings worldwide. However, mineral wool waste is often considered unrecyclable because of its fibrous nature and low density. In this paper, rock wool (RW and glass wool (GW were studied as alkali-activated material precursors without any additional co-binders. Both mineral wools were pulverized by a vibratory disc mill in order to remove the fibrous nature of the material. The pulverized mineral wools were then alkali-activated with a sodium aluminate solution. Compressive strengths of up to 30.0 MPa and 48.7 MPa were measured for RW and GW, respectively, with high flexural strengths measured for both (20.1 MPa for RW and 13.2 MPa for GW. The resulting alkali-activated matrix was a composite-type in which partly-dissolved fibers were dispersed. In addition to the amorphous material, sodium aluminate silicate hydroxide hydrate and magnesium aluminum hydroxide carbonate phases were identified in the alkali-activated RW samples. The only crystalline phase in the GW samples was sodium aluminum silicate. The results of this study show that mineral wool is a very promising raw material for alkali activation.

Recent materials compatibility studies in refractory metal-alkali metal systems for space power applications.

Science.gov (United States)

Harrison, R. W.; Hoffman, E. E.; Davies, R. L.

1972-01-01

Advanced Rankine and other proposed space power systems utilize refractory metals in contact with both single-phase and two-phase alkali metals at elevated temperatures. A number of recent compatibility experiments are described which emphasize the excellent compatibility of refractory metals with the alkali metals, lithium, sodium, and potassium, under a variety of environmental conditions. The alkali metal compatibilities of tantalum-, columbium-, molybdenum-, and tungsten-base alloys are discussed.

The evolution of strength and crystalline phases for alkali-activated ground blast furnace slag and fly ash-based geopolymers

KAUST Repository

Oh, Jae Eun

2010-02-01

The increase in strength and evolution of crystalline phases in inorganic polymer cement, made by the alkali activation of slag, Class C and Class F fly ashes, was followed using compressive strength test and synchrotron X-ray diffraction. In order to increase the crystallinity of the product the reactions were carried out at 80 °C. We found that hydrotalcite formed in both the alkali-activated slag cements and the fly ash-based geopolymers. Hydroxycancrinite, one member of the ABC-6 family of zeolites, was found only in the fly ash geopolymers. Assuming that the predominantly amorphous geopolymer formed under ambient conditions relates to the crystalline phases found when the mixture is cured at high temperature, we propose that the structure of this zeolitic precursor formed in Na-based high alkaline environment can be regarded as a disordered form of the basic building unit of the ABC-6 group of zeolites which includes poly-types such as hydroxycancrinite, hydroxysodalite and chabazite-Na. © 2009 Elsevier Ltd.

The evolution of strength and crystalline phases for alkali-activated ground blast furnace slag and fly ash-based geopolymers

International Nuclear Information System (INIS)

Oh, Jae Eun; Monteiro, Paulo J.M.; Jun, Ssang Sun; Choi, Sejin; Clark, Simon M.

2010-01-01

The increase in strength and evolution of crystalline phases in inorganic polymer cement, made by the alkali activation of slag, Class C and Class F fly ashes, was followed using compressive strength test and synchrotron X-ray diffraction. In order to increase the crystallinity of the product the reactions were carried out at 80 deg. C. We found that hydrotalcite formed in both the alkali-activated slag cements and the fly ash-based geopolymers. Hydroxycancrinite, one member of the ABC-6 family of zeolites, was found only in the fly ash geopolymers. Assuming that the predominantly amorphous geopolymer formed under ambient conditions relates to the crystalline phases found when the mixture is cured at high temperature, we propose that the structure of this zeolitic precursor formed in Na-based high alkaline environment can be regarded as a disordered form of the basic building unit of the ABC-6 group of zeolites which includes poly-types such as hydroxycancrinite, hydroxysodalite and chabazite-Na.

Extraction method for the determination of inorganic iodides in Rose Bengal labelled with 131I

International Nuclear Information System (INIS)

Lengyel, J.; Krtil, J.; Vecernik, J.

1982-01-01

An extraction method for the determination of inorganic iodides in Rose Bengal preparations labelled with 131 I is described. The method is based on the quantitative extraction of Rose Bengal into chloroform from acidic medium while the inorganic iodides remain in the aqueous phase. The method is simple, rapid, and reproducible. (author)

Iodide transport and breast cancer.

Science.gov (United States)

Poole, Vikki L; McCabe, Christopher J

2015-10-01

Breast cancer is the second most common cancer worldwide and the leading cause of cancer death in women, with incidence rates that continue to rise. The heterogeneity of the disease makes breast cancer exceptionally difficult to treat, particularly for those patients with triple-negative disease. To address the therapeutic complexity of these tumours, new strategies for diagnosis and treatment are urgently required. The ability of lactating and malignant breast cells to uptake and transport iodide has led to the hypothesis that radioiodide therapy could be a potentially viable treatment for many breast cancer patients. Understanding how iodide is transported, and the factors regulating the expression and function of the proteins responsible for iodide transport, is critical for translating this hypothesis into reality. This review covers the three known iodide transporters - the sodium iodide symporter, pendrin and the sodium-coupled monocarboxylate transporter - and their role in iodide transport in breast cells, along with efforts to manipulate them to increase the potential for radioiodide therapy as a treatment for breast cancer. © 2015 Society for Endocrinology.

Alkali adsorption on Ni(1 1 1) and their coadsorption with CO and O

International Nuclear Information System (INIS)

Politano, A.; Formoso, V.; Chiarello, G.

2008-01-01

The adsorption of alkalis (Na, K) on Ni(1 1 1) and their coadsorption with CO and O were studied by high-resolution electron energy loss spectroscopy. Loss measurements of clean alkali adlayers provided the expected behaviour of the alkali-substrate vibration energy as a function of the alkali coverage. This result was achieved by eliminating any trace of CO contamination from the alkali adlayer. As a matter of fact, a significant softening of the alkali-Ni vibration energy was revealed in the alkali + CO coadsorbed phase. Moreover, alkali coadsorption with oxygen caused a weakening of the O-Ni bond and a strengthening of the alkali-Ni bond

Complex crystals formed in the aqueous solution of copper(I) iodide and sodium iodide

International Nuclear Information System (INIS)

Sugasaka, Kazuhiko; Fujii, Ayako

1977-01-01

Crystals of different crystal habits were separated from the copper(I) iodide and sodium iodide solution and the thermal changes of the composition of copper(I) iodide and sodium iodide complexes were studied by chemical analysis, thermal analysis and X-ray diffractometry. Granular and columnar crystals were determined to be copper(I) iodide and sodium iodide dihydrate by X-ray diffraction analysis, respectively. Needle crystal (A) which was separated from the solution at 25 0 C was assumed to be Na 2 CuI 3 .6H 2 O. (A) was stable in its appearance in the air, but the X-ray diffraction pattern of (A) changed. Needle crystal (B) which was recrystallized at 10 0 C from mother liquor after the separation of crystal (A) was assumed to be NaCuI 2 .4H 2 O. (B) was hygroscopic and decomposed to precipitate copper(I) iodide with moisture in the air. (A) and (B) were found to change by heating and or drying, respectively, as follows: Na 2 CuI 3 .6H 2 O → (-2H 2 O, 80 0 C) → 2NaI.2H 2 O + CuI → (-4H 2 O, 160 0 C) → 2NaI + CuI → (+1/2O 2 , 450 0 C) → 2NaI + CuO + 1/2I 2 , NaCuI 2 .4H 2 O → (-4H 2 O, Dried) → NaI + CuI. (auth.)

Interaction of alkali metal nitrates with calcium carbonate and kyanite

International Nuclear Information System (INIS)

Protsyuk, A.P.; Malakhov, A.I.; Karabanov, V.P.; Lebedeva, L.P.

1978-01-01

Thermographic, thermodynamic and X-ray phase studies have been made into the interaction of alkali metal nitrates with calcium carbonate and kyanite. Examined among other things was the effect of water vapor and carbon dioxide on the interaction between alkali metal nitrates and kyanite. The chemical mechanism of the occurring processes has been established. The interaction with calcium carbonates results in the formation of alkali metal carbonates and calcium oxide with liberation of nitrogen oxide and oxygen. The products of the interaction with kyanite are shown to be identical with the compounds forming when alkali metal carbonates are used

Theoretical and experimental investigations on the behaviour of iodine during severe accidents: organic iodide, iodine/silver reaction, iodine/iron reaction. Pt. 4: organic iodide. Final report

International Nuclear Information System (INIS)

Hellmann, S.; Greger, G.U.; Funke, F.; Bleier, A.; Zeeh, W.

1995-11-01

Analysis of the consequences of severe accidents in nuclear power plants requires knowledge of the behaviour of radionuclides relevant from the radiological viewpoint. The role played by radioiodine is particularly important. In the current modelling of iodine behaviour the heterogeneous formation of organic iodide is not adequately taken into consideration owing to a lack of data or insufficient accuracy of data. This project is intended to eliminate some gaps in critical areas. This final report, part 4, describes the tests carried out in the two relevant areas - heterogeneous formation of organic coatings in the gas phase (containment atmosphere) - heterogeneous formation of organic iodide at organic coatings in aqueous phase (containment sump). Moreover, modelling suggestions how to include the resulting knowledge in the iodine accident behaviour code IMPAIR are given. (orig.) [de

Effect of alkali metal content of carbon on retention of iodine at high temperatures

International Nuclear Information System (INIS)

Evans, A.G.

1975-01-01

Activated carbon for filters in reactor confinement systems is intentionally impregnated with iodine salts to enhance the removal of radioiodine from air streams containing organic iodides. When a variety of commercial impregnated carbons were evaluated for iodine retention at elevated temperatures (4 hours at 180 0 C), wide variations in iodine penetration were observed. The alkali metal and iodine content of carbon samples was determined by neutron activation analysis, and a strong correlation was shown between the atom ratio of iodine to alkali metals in the carbons and the high-temperature retention performance. Carbons containing excess alkali (especially potassium) have iodine penetration values 10 to 100 times lower than carbons containing excess iodine. Both low I/K ratios and high pH values were shown essential to high efficiency iodine retention; therefore, conversion of elemental iodine to ionic iodine is the basic reaction mechanism. The natural high K + content and high pH coconut carbons make coconut the preferred natural base material for nuclear air cleaning applications. Studies show, however, that treatment of low potassium carbons with a mixture of KOH and I 2 may produce a product equal to or better than I 2 -impregnated coconut carbons at a lower cost. (U.S.)

Evaluation of quaternary ammonium halides for removal of methyl iodide from flowing air streams

International Nuclear Information System (INIS)

Freeman, W.P.; Mohacsi, T.G.; Kovach, J.L.

1985-01-01

The quaternary ammonium halides of several tertiary amines were used as impregnants on activated carbon and were tested for methyl iodide penetration in accordance with test Method A, ASTM D3803, 1979, ''Standard Test Methods for Radio-iodine Testing of Nuclear Grade Gas Phase Adsorbents''. The results suggest that the primary removal mechanism for methyl iodide-131 is isotopic exchange with the quaternary ammonium halide. For example, a 5 wt% impregnation of each of the tetramethyl, tetraethyl, tetrapropyl and tetrabutyl ammonium iodides on activated carbon yielded percent penetrations of 0.47, 0.53, 0.78, and 0.08 respectively when tested according to Method A of ASTM D3803. A sample impregnated with 5% tetramethyl ammonium hydroxide gave a methyl iodide penetration of 64.87%, thus supporting the isotopic exchange mechanism for removal. It has been a generally held belief that the success of tertiary amines as impregnants for radioiodine removal is a result of their ability to complex with the methyl iodide. The results of the work indicates that the superiority of the tertiary amines similar to triethylene diamine and quinuclidine, when compared to their straight chain analogs, is a result of their ease in reacting with methyl iodide-127 to form the quaternary ammonium iodide followed by isotopic exchange

Electrolytic method to make alkali alcoholates using ion conducting alkali electrolyte/separator

Science.gov (United States)

Joshi, Ashok V [Salt Lake City, UT; Balagopal, Shekar [Sandy, UT; Pendelton, Justin [Salt Lake City, UT

2011-12-13

Alkali alcoholates, also called alkali alkoxides, are produced from alkali metal salt solutions and alcohol using a three-compartment electrolytic cell. The electrolytic cell includes an anolyte compartment configured with an anode, a buffer compartment, and a catholyte compartment configured with a cathode. An alkali ion conducting solid electrolyte configured to selectively transport alkali ions is positioned between the anolyte compartment and the buffer compartment. An alkali ion permeable separator is positioned between the buffer compartment and the catholyte compartment. The catholyte solution may include an alkali alcoholate and alcohol. The anolyte solution may include at least one alkali salt. The buffer compartment solution may include a soluble alkali salt and an alkali alcoholate in alcohol.

Iodide uptake by negatively charged clay interlayers?

International Nuclear Information System (INIS)

Miller, Andrew; Kruichak, Jessica; Mills, Melissa; Wang, Yifeng

2015-01-01

Understanding iodide interactions with clay minerals is critical to quantifying risk associated with nuclear waste disposal. Current thought assumes that iodide does not interact directly with clay minerals due to electrical repulsion between the iodide and the negatively charged clay layers. However, a growing body of work indicates a weak interaction between iodide and clays. The goal of this contribution is to report a conceptual model for iodide interaction with clays by considering clay mineral structures and emergent behaviors of chemical species in confined spaces. To approach the problem, a suite of clay minerals was used with varying degrees of isomorphic substitution, chemical composition, and mineral structure. Iodide uptake experiments were completed with each of these minerals in a range of swamping electrolyte identities (NaCl, NaBr, KCl) and concentrations. Iodide uptake behaviors form distinct trends with cation exchange capacity and mineral structure. These trends change substantially with electrolyte composition and concentration, but do not appear to be affected by solution pH. The experimental results suggest that iodide may directly interact with clays by forming ion-pairs (e.g., NaI (aq) ) which may concentrate within the interlayer space as well as the thin areas surrounding the clay particle where water behavior is more structured relative to bulk water. Ion pairing and iodide concentration in these zones is probably driven by the reduced dielectric constant of water in confined space and by the relatively high polarizability of the iodide species. - Highlights: • Iodide sorption experiments were completed with a diverse array of clay minerals. • Iodide uptake trended with CEC and swamping electrolyte identity and concentration. • Results can be explained by considering the formation of ion pairs in clay interlayers

Tandem on-line continuous separations for atomic spectroscopic indirect analysis: iodide determination by ICP-AES

International Nuclear Information System (INIS)

Garcia, A.M.; Sanchez Uria, J.E.; Sanz-Medel, A.; Quintero Ortega, M.C.; Bautista, J.C.

1992-01-01

A sensitive and selective indirect determination of iodide by inductively coupled plasma emission spectrometry (ICP-AES) based on the principle of tandem on-line continuous separations as an alternative means of introducing samples into plasmas is proposed. Iodide is continuously extracted as an ion-pair into xylene by mixing the sample with Hg(II) and dipyridil solutions. The organic phase (containing the analyte in [Hg(Dipy) 2 ]I 2 form) is on-line continuously mixed with NaBH 4 (in DMF) and acetic acid solutions. Mercury vapour continuously generated from this organic phase is separated in a classical U-type gas-liquid separation device. The system has been optimized for the continuous extraction of KI, for the direct generation of cold mercury vapour from xylene and for the final ICP-AES determination of mercury. The optimised method has been applied to the determination of iodide (detection limit 20 ng/ml of iodide) in table salt and in synthetic samples. Very good agreement between found and certified results was observed. The usefulness and convenience of such alternative sample chemical pretreatment/presentation to the ICP is thus demonstrated for indirect determinations to be carried out by atomic spectroscopy methods. (authors)

Iodide uptake by negatively charged clay interlayers?

Science.gov (United States)

Miller, Andrew; Kruichak, Jessica; Mills, Melissa; Wang, Yifeng

2015-09-01

Understanding iodide interactions with clay minerals is critical to quantifying risk associated with nuclear waste disposal. Current thought assumes that iodide does not interact directly with clay minerals due to electrical repulsion between the iodide and the negatively charged clay layers. However, a growing body of work indicates a weak interaction between iodide and clays. The goal of this contribution is to report a conceptual model for iodide interaction with clays by considering clay mineral structures and emergent behaviors of chemical species in confined spaces. To approach the problem, a suite of clay minerals was used with varying degrees of isomorphic substitution, chemical composition, and mineral structure. Iodide uptake experiments were completed with each of these minerals in a range of swamping electrolyte identities (NaCl, NaBr, KCl) and concentrations. Iodide uptake behaviors form distinct trends with cation exchange capacity and mineral structure. These trends change substantially with electrolyte composition and concentration, but do not appear to be affected by solution pH. The experimental results suggest that iodide may directly interact with clays by forming ion-pairs (e.g., NaI(aq)) which may concentrate within the interlayer space as well as the thin areas surrounding the clay particle where water behavior is more structured relative to bulk water. Ion pairing and iodide concentration in these zones is probably driven by the reduced dielectric constant of water in confined space and by the relatively high polarizability of the iodide species. Copyright © 2015 Elsevier Ltd. All rights reserved.

Micelle formation during extraction of alkali elements from strongly alkaline mediums

International Nuclear Information System (INIS)

Apanasenko, V.V.; Reznik, A.M.; Bukin, V.I.; Brodskaya, A.V.

1988-01-01

Extraction of potassium, rubidium and cesium by phenol reagents in hydrocarbon solvents from strongly alkakine solutions was considered. Tendency of prepared alkali metal phenolates to form micelles in aqueous and organic phases was revealed. Phenolates tendency to form micelles is dictated mainly by the size and position of hydrocarbon substituent in molecule. It is shown that when micelles form in organic phase, alkali elements can be extracted both according to cation-exchange mechanism and according to micellar one. It is noted that alkai element extraction from strongly alkaline media requires the correct choice of extractant: alkali metal phenolate shouldn't form micelles in aqueous solution. n-Alkyl- and arylphenoldisulfides and polysulfides are most preferable for solvent extraction among considered phenol derivatives

Control of alkali species in gasification systems: Final report

Energy Technology Data Exchange (ETDEWEB)

Turn, S.; Kinoshita, C.; Ishimura, D. Zhou, J.; Hiraki, T.; Masutani, S.

2000-07-13

Gas-phase alkali metal compounds contribute to fouling, slagging, corrosion, and agglomeration problems in energy conversion facilities. One mitigation strategy applicable at high temperature is to pass the gas stream through a fixed bed sorbent or getter material, which preferentially absorbs alkali via physical adsorption or chemisorption. This report presents results of an experimental investigation of high-temperature alkali removal from a hot filtered gasifier product gas stream using a packed bed of sorbent material. Two getter materials, activated bauxite and emathlite, were tested at two levels of space time by using two interchangeable reactors of different internal diameters. The effect of getter particle size was also investigated.

Reaction of 1-bromo-3-chloropropane with tellurium and dimethyl telluride in the system of hydrazine hydrate-alkali

International Nuclear Information System (INIS)

Russavskaya, N.V.; Levanova, E.P.; Sukhomazova, Eh.N.; Grabel'nykh, V.A.; Elaev, A.V.; Klyba, L.V.; Zhanchipova, E.R.; Albanov, A.I.; Korotaeva, I.M.; Toryashinova, D.S.D.; Korchevin, N.A.

2006-01-01

A synthesis of oligomeric substance of thiocol type, the poly(trimethyleneditelluride), from 1-bromo-3-chloropropane and elemental tellurium is performed using a hydrazine hydrate-alkali system. Reductive splitting of the tellurocol followed by alkylation with methyl iodide give rise to preparation of bis(methyltelluro)propane, which was synthesized also from dimethyl telluride and 1,3-dihalopropanes using the N 2 H 4 ·H 2 O/KOH system. The reaction products were characterized by elementary analysis, NMR, and IR spectra. Mass spectra of the synthesized low molecular weight organotellurium compounds are considered [ru

Growth of mercuric iodide single crystals from dimethylsulfoxide

International Nuclear Information System (INIS)

Carlston, R.C.

1976-01-01

Dimethylsulfoxide is used as a solvent for the growth of red mercuric iodide (HgI 2 ) crystals for use in radiation detectors. The hygroscopic property of the solvent allows controlled amounts of water to enter into the solvent phase and diminish the large solubility of HgI 2 so that the precipitating solid collects as well-defined euhedral crystals which grow into a volume of several cc

The characterisation of vapour-phase alkali metal-tellurium-oxygen species

International Nuclear Information System (INIS)

Gomme, R.A.; Ogden, J.S.; Bowsher, B.R.

1986-10-01

Detailed assessments of hypothetical severe accidents in light water reactors require the identification of the chemical forms of the radionuclides in order to determine their transport characteristics. Caesium and tellurium are important volatile fission products in accident scenarios. This report describes detailed studies to characterise the chemical species that vaporise from heated mixtures of various alkali metal-tellurium-oxygen systems. The molecular species were characterised by a combination of quadrupole mass spectrometry and matrix isolation-infrared spectroscopy undertaken in conjunction with experiments involving oxygen-18 substitution. The resulting spectra were interpreted in terms of a vapour-phase molecule with the stoichiometry M 2 TeO 3 (M = K,Rb,Cs) for M/Te molecular ratios of ∼ 2, and polymeric species for ratios < 2. This work has demonstrated the stability of caesium tellurite. The formation of this relatively low-volatility, water-soluble species could significantly modify the transport and release of caesium and tellurium. The data presented in this report should allow more comprehensive thermodynamic calculations to be undertaken that assist in the quantification of fission product behaviour during severe reactor accidents. (author)

Electrochemical reaction rates in a dye-sensitised solar cell - the iodide/tri-iodide redox system

DEFF Research Database (Denmark)

Bay, L.; West, K.; Winther-Jensen, B.

2006-01-01

The electrochemical reaction rate of the redox couple iodide/tri-iodide in acetonitrile is characterised by impedance spectroscopy. Different electrode materials relevant for the function of dye-sensitised solar cells (DSSC) are investigated. Preferably, the reaction with the iodide....../tri-iodide couple should be fast at the counter electrode, i.e. this electrode must have a high catalytic activity towards the redox couple, and the same reaction must be slow on the photo electrode. The catalytic activity is investigated for platinum, poly(3,4-ethylenedioxythiophene) (PEDOT), polypyrrole (PPy......), and polyaniline (PANI)-all deposited onto fluorine-doped tin oxide (FTO) glass. Both Pt and PEDOT are found to have sufficiently high catalytic activities for practical use as counter electrodes in DSSC. The reaction resistance on FTO and anatase confirmed the beneficial effect of a compact anatase layer on top...

Electrochemical reaction rates in a dye sentisised solar cell - the iodide/tri-iodide redox system

DEFF Research Database (Denmark)

Bay, Lasse; West, Keld; Winter-Jensen, Bjørn

2006-01-01

The electrochemical reaction rate of the redox couple iodide / tri-iodide in acetonitrile is characterised by impedance spectroscopy. Different electrode materials relevant for the function of dye-sensitised solar cells (DSSC) are investigated. Preferably, the reaction with the iodide / tri......-iodide couple should be fast at the counter electrode, i.e. this electrode must have a high catalytic activity towards the redox couple, and the same reaction must be slow on the photo electrode. The catalytic activity is investigated for platinum, poly(3,4-ethylenedioxythiophene) (PEDOT), polypyrrole (PPy......), and polyaniline (PANI) - all deposited onto fluorine doped tin oxide (FTO) glass. Both Pt and PEDOT are found to have sufficiently high catalytic activities for practical use as counter electrode in DSSC. The reaction resistance on FTO and anatase confirmed the beneficial effect of a compact anatase layer on top...

Compression-Driven Enhancement of Electronic Correlations in Simple Alkali Metals

Science.gov (United States)

Fabbris, Gilberto; Lim, Jinhyuk; Veiga, Larissa; Haskel, Daniel; Schilling, James

2015-03-01

Alkali metals are the best realization of the nearly free electron model. This scenario appears to change dramatically as the alkalis are subjected to extreme pressure, leading to unexpected properties such as the departure from metallic behavior in Li and Na, and the occurrence of remarkable low-symmetry crystal structures in all alkalis. Although the mechanism behind these phase transitions is currently under debate, these are believed to be electronically driven. In this study the high-pressure electronic and structural ground state of Rb and Cs was investigated through low temperature XANES and XRD measurements combined with ab initio calculations. The results indicate that the pressure-induced localization of the conduction band triggers a Peierls-like mechanism, inducing the low symmetry phases. This localization process is evident by the pressure-driven increase in the number of d electrons, which takes place through strong spd hybridization. These experimental results indicate that compression turns the heavy alkali metals into strongly correlated electron systems. Work at Argonne was supported by DOE No. DE-AC02-06CH11357. Research at Washington University was supported by NSF DMR-1104742 and CDAC/DOE/NNSA DE-FC52-08NA28554.

Enhanced iodide sequestration by 3-biphenyl-5,6-dihydroimidazo 2,1-b thiazole in sodium/iodide sym-porter (NIS)-expressing cells

International Nuclear Information System (INIS)

Lecat-Guillet, N.; Ambroise, Y.

2008-01-01

The ability of the sodium/iodide sym-porter (NIS) to take up iodide has long provided the basis for cyto-reductive gene therapy and cancer treatment with radio-iodide. One of the major limitations of this approach is that radio-iodide retention in NIS-expressing cells is not sufficient for their destruction. We identified and characterized a small organic molecule capable of increasing iodide retention in HEK293 cells permanently transfected with human NIS cDNA (hNIS-HEK293) and in the rat thyroid-derived cell line FRTL-5. In the presence of 3-biphenyl-4'-yl-5,6-dihydroimidazo[2,1-b)thiazole (ISA1), the transmembrane iodide concentration gradient was increased up to 4.5-fold. Our experiments indicate that the imidazo-thiazole derivative acts either by inhibiting anion efflux mechanisms, or by promoting the relocation of iodide into subcellular compartments. This new compound is not only an attractive chemical tool to investigate the mechanisms of iodide flux at the cellular level, but also opens promising perspectives in the treatment of cancer after NIS gene transfer. (authors)

Analysis for iodide in groundwater by x-ray fluorescence spectrometry after collection as silver iodide on activated charcoal

International Nuclear Information System (INIS)

Howe, P.T.

1980-01-01

The report describes the determination of microgram quantities of iodide in water by X-ray fluorescence spectrometry. The iodide is concentrated by precipitation as silver iodide on activated charcoal. If a 60-mL sample is available, a concentration of 0.12 mg/L can be detected. Precision (2σ) at the 1-mg/L level is +- 0.08 mg/L. (auth)

Alkali silica reaction (ASR) in cement free alkali activated sustainable concrete.

Science.gov (United States)

2016-12-19

This report summarizes the findings of an experimental evaluation into alkali silica : reaction (ASR) in cement free alkali-activated slag and fly ash binder concrete. The : susceptibility of alkali-activated fly ash and slag concrete binders to dele...

Interaction of simple indium iodides with silver- and aluminium iodides

International Nuclear Information System (INIS)

Denisov, Yu.N.; Halova, N.S.; Fedorov, P.I.

1976-01-01

Fusibility diagrams of the systems InI-AlI 3 , InI-AgI, InI 2 -AgI, and InI 2 -AlI 3 have been studied. In the system InI-AlI 3 a compound InAlI 4 has been detected having a melting point 194 deg C and two lamination regions. In the system InI-AgI two compounds In 2 AgI 3 and InAgI 2 are formed which melt incongruently at 272 deg and 220 deg C, respectively. The formation of the compounds has been confirmed by X-ray phase analysis. Specific electroconductivity of a number of alloys of the system InI-AlI 3 has been studied. The systems of eutectic type formed by diiodide of indium with iodides of silver and aluminium have been studied by thermal and X-ray analysis and by measuring electroconductivity

Kinetic Isotope Effects in the Reduction of Methyl Iodide

DEFF Research Database (Denmark)

Holm, Torkil

1999-01-01

a Grignard reagent to methyl iodide, and for reduction of methyl iodide with tributyltin hydride or with gaseous hydrogen iodide. Very small KIE's were found for electron transfer to methyl iodide from magnesium in ether or from sodium in ammonia. The reason may be that these reactions are transport...

Electron stimulated reactions of methyl iodide coadsorbed with amorphous solid water

International Nuclear Information System (INIS)

Perry, C. C.; Faradzhev, N. S.; Madey, T. E.; Fairbrother, D. H.

2007-01-01

The electron stimulated reactions of methyl iodide (MeI) adsorbed on and suspended within amorphous solid water (ice) were studied using a combination of postirradiation temperature programmed desorption and reflection absorption infrared spectroscopy. For MeI adsorbed on top of amorphous solid water (ice), electron beam irradiation is responsible for both structural and chemical transformations within the overlayer. Electron stimulated reactions of MeI result principally in the formation of methyl radicals and solvated iodide anions. The cross section for electron stimulated decomposition of MeI is comparable to the gas phase value and is only weakly dependent upon the local environment. For both adsorbed MeI and suspended MeI, reactions of methyl radicals within MeI clusters lead to the formation of ethane, ethyl iodide, and diiodomethane. In contrast, reactions between the products of methyl iodide and water dissociation are responsible for the formation of methanol and carbon dioxide. Methane, formed as a result of reactions between methyl radicals and either parent MeI molecules or hydrogen atoms, is also observed. The product distribution is found to depend on the film's initial chemical composition as well as the electron fluence. Results from this study highlight the similarities in the carbon-containing products formed when monohalomethanes coadsorbed with amorphous solid water are irradiated by either electrons or photons

Gamma-ray radiolysis of methyl iodide in air, in presence of water vapor

International Nuclear Information System (INIS)

Aubert, F.

2002-03-01

This work aims at modelling the processes involved in gamma-radiolysis of methyl iodide diluted in air in presence of steam. It is to determine quantitative and qualitative information, to quantify the importance of the organic iodides destruction in case of a nuclear reactor accident. The main data for radiochemistry and iodine compounds (I x O y and INO x ) formation were reviewed and analysed. Literature data about air products radiolysis reactivity towards I 2 and CH 3 I were used to develop a mechanistic model for methyl iodide destruction in the gas phase under gamma irradiation. An ab initio study was realised for a better understanding of atomic nitrogen ( 4 S and 2 D) reactivity towards CH 3 I. The model was tested on the available experimental data and constitute a way to investigate the main processus involved in methyl iodide destruction. For the low CH 3 I concentrations, about 10 -7 - 10 -8 mol.dm -3 , N and e - are mainly responsible for the destruction. I 2 O 4 (highest iodine oxide in the model) and IONO 2 are the main resulting iodinated' compounds. (author)

Iodide adsorption on the surface of chemically pretreated clinoptilolite

International Nuclear Information System (INIS)

Chmielewska-Horvatova, E.; Lesny, J.

1995-01-01

The possibility to use the monoionic Ag +- form (eventually Hg +- and Hg 2+ -forms) of clinoptilolite of domestic origin for radioactive iodide elimination from waters has been studied. The capacity of the monoforms of clinoptilolite towards iodide exceeds many times that of the capacity of clinoptilolite in natural form. Due to the low solubility product of AgI, Hg 2 I 2 and HgI 2 iodides generate precipitates on the zeolite surface. Rtg analyses of the silver form of clinoptilolite after sorption of iodide demonstrate the formation of new crystals on the zeolite surface. The influence of interfering anions on the adsorption capacity of silver clinoptilolite towards iodide was investigated, too. Kinetic curves of iodide desorption from the surface of silver and mercury clinoptilolite were compared. Simultaneously, adsorption isotherms for the systems aqueous iodide solution/Ag-, Hg-clinoptilolite were determined. (author) 6 refs.; 7 figs.; 4 tabs

Measures for simultaneous minimization of alkali related operating problems, Phase 2; Aatgaerder foer samtidig minimering av alkalirelaterade driftproblem, Etapp 2. Ramprogram

Energy Technology Data Exchange (ETDEWEB)

Gyllenhammar, Marianne; Herstad Svaerd, Solvie; Davidsson, Kent; Aamand, Lars-Erik; Steenari, Britt-Marie; Folkeson, Nicklas; Pettersson, Jesper; Svensson, Jan-Erik; Boss, Anna; Johansson, Linda; Kassman, Haakan

2007-12-15

agglomeration temperature is reduced by about 50 deg C after 12 h of combustion with wood and straw pellets. Sticky alkali-silicate particles reduce the agglomeration temperature. The bed sand particles are coated with alkali (potassium) and also calcium. The straw ash itself forms sticky parts which contribute to the low agglomeration temperature. Alkali chloride will be formed and vaporized to the gas phase. It will then be measured in the flue gas and will later condensate on the tubes in the back pass. Small amounts of alkali sulphates will also be formed. The alkali chloride content will increase from 1-2 ppm to 44 ppm in the flue gas when the straw pellets are added. The flue gas contains also 9 ppm SO{sub 2} and 85 ppm HCl. All measures had a positive influence on the agglomeration temperature (except the addition of ammonium sulphate which was added to the cyclone inlet and did not have any significant influence on the bed). The results also showed that all measures, except co-combustion with de-inking sludge and changing bed material to sieved bottom bed ash from a PFBC boiler (PFBC-ash), lowered the alkali chloride content in deposits and therefore the risk of corrosion. Initial corrosion was found in the reference case at test probes of 304L exposed 4 hours at 600 deg C. Chromium depletion of the tube material showed that the protected chromium oxide had been damaged. By comparing the different measures in part two, it could be concluded that cocombustion of sewage sludge gave the best overall effect. The judgement was based on the effects concerning bed agglomeration, level of alkali chloride in the flue gas, deposits and initial corrosion. One disadvantage of sewage sludge is the large amount of ash which increases the ash load significantly. In the tests the ash flow increased four times more than for the reference case. Simultaneous addition of kaolin and ammonium sulphate also had a favourable impact both in the bed and on the alkali chlorides in the gas phase

Alkali Metal Modification of Silica Gel-Based Stationary Phase in Gas Chromatography

Directory of Open Access Journals (Sweden)

Ashraf Yehia El-Naggar

2013-01-01

Full Text Available Modification of the precipitated silica gel was done by treatment with alkali metal (NaCl before and after calcination. The silica surfaces before and after modification were confirmed by infrared spectroscopy in order to observe the strength and abundance of the acidic surface OH group bands which play an important role in the adsorption properties of polar and nonpolar solutes. The surface-modified silica gels were tested as GC solid stationary phases in terms of the separation efficiency for various groups of non-polar and polar solutes. Also, thermodynamic parameters (ΔH, ΔG, and ΔS were determined using n-hexane as a probe in order to show the adsorbate-adsorbent interaction. It was observed that the non-polar solutes could be separated Independent on the reactivity and porosity of the silica surfaces. The efficiency of the surface-modified silica gels to separate the aromatic hydrocarbons seemed to be strongly influenced by the density of the surface hydroxyls.

Ferroelastic Fingerprints in Methylammonium Lead Iodide Perovskite

KAUST Repository

Hermes, Ilka M.

2016-02-12

Methylammonium lead iodide (MAPbI3) perovskite materials show an outstanding performance in photovoltaic devices. However, certain material properties, especially the possible ferroic behavior, remain unclear. We observed distinct nanoscale periodic domains in the piezoresponse of MAPbI3(Cl) grains. The structure and the orientation of these striped domains indicate ferroelasticity as their origin. By correlating vertical and lateral piezoresponse force microscopy experiments performed at different sample orientations with x-ray diffraction, the preferred domain orientation was suggested to be the a1-a2-phase. The observation of these ferroelastic fingerprints appears to strongly depend on the film texture and thus the preparation route. The formation of the ferroelastic twin domains could be induced by internal strain during the cubic-tetragonal phase transition.

21 CFR 172.375 - Potassium iodide.

Science.gov (United States)

2010-04-01

... Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.375 Potassium iodide. The food additive potassium iodide may be...

In Vitro Bioavailability Study of an Antiviral Compound Enisamium Iodide

OpenAIRE

Eleonore Haltner-Ukomadu; Svitlana Gureyeva; Oleksii Burmaka; Andriy Goy; Lutz Mueller; Grygorii Kostyuk; Victor Margitich

2018-01-01

An investigation into the biopharmaceutics classification and a study of the in vitro bioavailability (permeability and solubility) of the antiviral compound enisamium iodide (4-(benzylcarbamoyl)-1-methylpyridinium iodide) were carried out. The solubility of enisamium iodide was determined in four different buffers. Apparent intestinal permeability (Papp) of enisamium iodide was assessed using human colon carcinoma (Caco-2) cells at three concentrations. The solubility of enisamium iodide in ...

Modelling iodide – iodate speciation in atmospheric aerosol: Contributions of inorganic and organic iodine chemistry

Directory of Open Access Journals (Sweden)

S. Pechtl

2007-01-01

Full Text Available The speciation of iodine in atmospheric aerosol is currently poorly understood. Models predict negligible iodide concentrations but accumulation of iodate in aerosol, both of which is not confirmed by recent measurements. We present an updated aqueous phase iodine chemistry scheme for use in atmospheric chemistry models and discuss sensitivity studies with the marine boundary layer model MISTRA. These studies show that iodate can be reduced in acidic aerosol by inorganic reactions, i.e., iodate does not necessarily accumulate in particles. Furthermore, the transformation of particulate iodide to volatile iodine species likely has been overestimated in previous model studies due to negligence of collision-induced upper limits for the reaction rates. However, inorganic reaction cycles still do not seem to be sufficient to reproduce the observed range of iodide – iodate speciation in atmospheric aerosol. Therefore, we also investigate the effects of the recently suggested reaction of HOI with dissolved organic matter to produce iodide. If this reaction is fast enough to compete with the inorganic mechanism, it would not only directly lead to enhanced iodide concentrations but, indirectly via speed-up of the inorganic iodate reduction cycles, also to a decrease in iodate concentrations. Hence, according to our model studies, organic iodine chemistry, combined with inorganic reaction cycles, is able to reproduce observations. The presented chemistry cycles are highly dependent on pH and thus offer an explanation for the large observed variability of the iodide – iodate speciation in atmospheric aerosol.

Flavonoid rutin increases thyroid iodide uptake in rats.

Directory of Open Access Journals (Sweden)

Carlos Frederico Lima Gonçalves

Full Text Available Thyroid iodide uptake through the sodium-iodide symporter (NIS is not only an essential step for thyroid hormones biosynthesis, but also fundamental for the diagnosis and treatment of different thyroid diseases. However, part of patients with thyroid cancer is refractory to radioiodine therapy, due to reduced ability to uptake iodide, which greatly reduces the chances of survival. Therefore, compounds able to increase thyroid iodide uptake are of great interest. It has been shown that some flavonoids are able to increase iodide uptake and NIS expression in vitro, however, data in vivo are lacking. Flavonoids are polyhydroxyphenolic compounds, found in vegetables present in human diet, and have been shown not only to modulate NIS, but also thyroperoxidase (TPO, the key enzyme in thyroid hormones biosynthesis, besides having antiproliferative effect in thyroid cancer cell lines. Therefore, we aimed to evaluate the effect of some flavonoids on thyroid iodide uptake in Wistar rats in vivo. Among the flavonoids tested, rutin was the only one able to increase thyroid iodide uptake, so we decided to evaluate the effect of this flavonoid on some aspects of thyroid hormones synthesis and metabolism. Rutin led to a slight reduction of serum T4 and T3 without changes in serum thyrotropin (TSH, and significantly increased hypothalamic, pituitary and brown adipose tissue type 2 deiodinase and decreased liver type 1 deiodinase activities. Moreover, rutin treatment increased thyroid iodide uptake probably due to the increment of NIS expression, which might be secondary to increased response to TSH, since TSH receptor expression was increased. Thus, rutin might be useful as an adjuvant in radioiodine therapy, since this flavonoid increased thyroid iodide uptake without greatly affecting thyroid function.

Potassium Iodide

Science.gov (United States)

... certain other liquids including low-fat white or chocolate milk, flat soda, orange juice, raspberry syrup, or ... Potassium iodide may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away: swollen glands metallic taste in the ...

An exploratory study of alkali sulfate aerosol formation during biomass combustion

DEFF Research Database (Denmark)

Løj, Lusi Hindiyarti; Frandsen, Flemming; Livbjerg, Hans

2008-01-01

mechanism. The modeling predictions are compared to data from laboratory experiments and entrained flow reactor experiments available in the literature. The analysis support that alkali sulfate aerosols are formed from homogeneous nucleation following a series of steps occurring in the gas phase. The rate......It is still in discussion to what extent alkali sulfate aerosols in biomass combustion are formed in the gas phase by a homogeneous mechanism or involve heterogeneous or catalyzed reactions. The present study investigates sulfate aerosol formation based on calculations with a detailed gas phase......-limiting step may be the oxidation of sulfite to sulfate, rather than the oxidation of SO2 to SO3 proposed previously. Even though the proposed model is consistent with experimental observations, experiments in a rigorously homogeneous system are called for to test its validity....

Development of alkali activated cements and concrete mixture design with high volumes of red mud

OpenAIRE

Krivenko, Pavel; Kovalchuk, Oleksandr; Pasko, Anton; Croymans, Tom; Hutt, Mikael; Lutter, Guillaume; Vandevenne, Niels; Schreurs, Sonja; Schroeyers, Wouter

2017-01-01

Dedicated cement compositions were formulated to enable the incorporation of large volume fractions of red mud in alkali activated cements, taking into account the role of the aluminosilicate phase in the processes of hydration and hardening. High volume red mud alkali activated cements were synthesized using a proper combination of red mud, low basic aluminosilicate compounds with a glass phase (blast-furnace slag) and additives selected from high-basic Ca-containing cements with a crystalli...

Regioselective conversion of primary alcohols into iodides in unprotected methyl furanosides and pyranosides

DEFF Research Database (Denmark)

Skaanderup, Philip Robert; Poulsen, Carina Storm; Hyldtoft, Lene

2002-01-01

Two methods are described for the regioselective displacement of the primary hydroxy group in methyl glycosides with iodide. The first method is a modification of a literature procedure employing triphenylphosphine and iodine, where purification has been carried out on a reverse phase column in o...

Alkali roasting of bomar ilmenite: rare earths recovery and physico-chemical changes

Directory of Open Access Journals (Sweden)

Sanchez-Segado Sergio

2014-11-01

(FeTiO3 is presented as a process route for integrated beneficiation of the mineral for rutile-rich phase and rare earth oxides; the latter is released as a consequence of physical changes in the ilmenite matrix, during the water leaching after roasting. The oxidative alkali roasting transforms ilmenite mineral into water-insoluble alkali titanate and water-soluble ferrite. After roasting the insoluble alkali titanate is separated from rare-earth oxide mixture in colloidal form and water-soluble ferrite. Further leaching of alkali titanate is carried out with oxalic (0.3M and ascorbic (0.01M acid solution which removes the remaining Fe2+ ions into the leachate and allows precipitation of high-purity synthetic rutile containing more than 95% TiO2. Iron is removed as iron oxalate. The physico-chemical changes occurred during the roasting and leaching processes are reported by comparing the role of alkali on the roasting process and product morphologies formed.

Prevention of organic iodide formation in BWR's

International Nuclear Information System (INIS)

Karjunen, T.; Laitinen, T.; Piippo, J.; Sirkiae, P.

1996-01-01

During an accident, many different forms of iodine may emerge. Organic iodides, such as methyl iodide and ethyl iodide, are relatively volatile, and thus their appearance leads to increased concentration of gaseous iodine. Since organic iodides are also relatively immune to most accident mitigation measures, such as sprays and filters, they can affect the accident source term significantly even when only a small portion of iodine is in organic form. Formation of organic iodides may not be limited by the amount of organic substances available. Excessive amounts of methane can be produced, for example, during oxidation of boron carbide, which is used in BWR's as a neutron absorber material. Another important source is cable insulation. In a BWR, a large quantity of cables is placed below the pressure vessel. Thus a large quantity of pyrolyse gases will be produced, should the vessel fail. Organic iodides can be formed as a result of many different reactions, but at least in certain conditions the main reaction takes place between an organic radical produced by radiolysis and elemental iodine. A necessary requirement for prevention of organic iodide production is therefore that the pH in the containment water pools is kept high enough to eliminate formation of elemental iodine. In a typical BWR the suppression pool water is usually unbuffered. As a result, the pH may be dominated by chemicals introduced during an accident. If no system for adding basic chemicals is operable, the main factor affecting pool water pH may be hydrochloric acid released during cable degradation. Should this occur, the conditions could be very favorable for production of elemental iodine and, consequently, formation of organic iodides. Although high pH is necessary for iodine retention, it could have also adverse effects. High pH may, for example, accelerate corrosion of containment materials and alter the characteristics of the solid corrosion products. (author) 6 figs., 1 tab., 13 refs

Alkali control of high-grade metamorphism and granitization

Directory of Open Access Journals (Sweden)

Oleg G. Safonov

2014-09-01

Full Text Available We review petrologic observations of reaction textures from high-grade rocks that suggest the passage of fluids with variable alkali activities. Development of these reaction textures is accompanied by regular compositional variations in plagioclase, pyroxenes, biotite, amphibole and garnet. The textures are interpreted in terms of exchange and net-transfer reactions controlled by the K and Na activities in the fluids. On the regional scale, these reactions operate in granitized, charnockitized, syenitized etc. shear zones within high-grade complexes. Thermodynamic calculations in simple chemical systems show that changes in mineral assemblages, including the transition from the hydrous to the anhydrous ones, may occur at constant pressure and temperature due only to variations in the H2O and the alkali activities. A simple procedure for estimating the activity of the two major alkali oxides, K2O and Na2O, is implemented in the TWQ software. Examples of calculations are presented for well-documented dehydration zones from South Africa, southern India, and Sri Lanka. The calculations have revealed two end-member regimes of alkalis during specific metamorphic processes: rock buffered, which is characteristic for the precursor rocks containing two feldspars, and fluid-buffered for the precursor rocks without K-feldspar. The observed reaction textures and the results of thermodynamic modeling are compared with the results of available experimental studies on the interaction of the alkali chloride and carbonate-bearing fluids with metamorphic rocks at mid-crustal conditions. The experiments show the complex effect of alkali activities in the fluid phase on the mineral assemblages. Both thermodynamic calculations and experiments closely reproduce paragenetic relations theoretically predicted by D.S. Korzhinskii in the 1940s.

Behaviour of gaseous alkali compounds from coal gasification

International Nuclear Information System (INIS)

Nykaenen, J.

1996-01-01

In this project the behaviour of alkali compounds has been studied with a chemical equilibrium model. The goal is to evaluate the possibilities to remove the sodium and potassium compounds together with the fly ash particles by using a ceramic honeycomb filter. The studied processes include both CO 2 /O 2 - and air-blown gasification and combustion. The results show that the difference between the processes with flue gas recirculation and air-blown processes is small. This is due to that the equilibrium concentration of the dominant gaseous alkali compound, chloride, is more or less the same in both processes. This research project is closely connected to the EU-project coordinated by the Delft University of Technology (DUT). In that project alkali concentration of the fuel gas from a 1.6 MW pilot plant will be measured. During the next phase of this research the results from DUT will be compared with the results of this presentation. (author)

Alkali metal and alkali earth metal gadolinium halide scintillators

Science.gov (United States)

Bourret-Courchesne, Edith; Derenzo, Stephen E.; Parms, Shameka; Porter-Chapman, Yetta D.; Wiggins, Latoria K.

2016-08-02

The present invention provides for a composition comprising an inorganic scintillator comprising a gadolinium halide, optionally cerium-doped, having the formula A.sub.nGdX.sub.m:Ce; wherein A is nothing, an alkali metal, such as Li or Na, or an alkali earth metal, such as Ba; X is F, Br, Cl, or I; n is an integer from 1 to 2; m is an integer from 4 to 7; and the molar percent of cerium is 0% to 100%. The gadolinium halides or alkali earth metal gadolinium halides are scintillators and produce a bright luminescence upon irradiation by a suitable radiation.

Kinetic method for determination of iodide ion ultramicroamounts. Kineticheskij sposob opredeleniya ul'tramikrokolichestv iodid-ionov

Energy Technology Data Exchange (ETDEWEB)

Barkauskas, Yu K; Ramanauskas, Eh I

1980-04-03

A kinetic method for iodides ultramicroamount determination from their catalytic effect on oxidation of malachite green with chloramine B in the presence of acetone at pH 5.78+-0.3 is developed. The induction period of the reaction is determined from a change in the redox potential of the system. The induction period is proportional to the iodides concentration. Determination limit of iodides is equal to 4 ..mu..g iodide per 100 l of solution. More than 10/sup 5/-multiple amounts of K/sup +/, Na/sup +/, NH/sub 4//sup +/, Ba/sup 2 +/, Al/sup 3 +/, Cu/sup 2 +/, Mg/sup 2 +/, SO/sub 4//sup 2 -/, Cl/sup -/, MoO/sub 4//sup 2 -/, NO/sub 3//sup -/, ClO/sub 3//sup -/, IO/sub 3//sup -/, IO/sub 4//sup -/, ClO/sub 4//sup -/, BrO/sub 3//sup -/; 10/sup 5/-10/sup 3/-multiple amounts of Cr/sup 3 +/, Fe/sup 3 +/, Sn/sup 2 +/, S/sup 2 -/, MnO/sub 4//sup -/, NO/sub 2//sup -/ etc. do not interfere with the determination, while 10-multiple amounts of SCN, 0.2-multiple quantities of Ag/sup +/, Hg/sub 2//sup 2 +/ do.

Electronic and structural ground state of heavy alkali metals at high pressure

Science.gov (United States)

Fabbris, G.; Lim, J.; Veiga, L. S. I.; Haskel, D.; Schilling, J. S.

2015-02-01

Alkali metals display unexpected properties at high pressure, including emergence of low-symmetry crystal structures, which appear to occur due to enhanced electronic correlations among the otherwise nearly free conduction electrons. We investigate the high-pressure electronic and structural ground state of K, Rb, and Cs using x-ray absorption spectroscopy and x-ray diffraction measurements together with a b i n i t i o theoretical calculations. The sequence of phase transitions under pressure observed at low temperature is similar in all three heavy alkalis except for the absence of the o C 84 phase in Cs. Both the experimental and theoretical results point to pressure-enhanced localization of the valence electrons characterized by pseudogap formation near the Fermi level and strong s p d hybridization. Although the crystal structures predicted to host magnetic order in K are not observed, the localization process appears to drive these alkalis closer to a strongly correlated electron state.

In Vitro Bioavailability Study of an Antiviral Compound Enisamium Iodide

Directory of Open Access Journals (Sweden)

Eleonore Haltner-Ukomadu

2018-01-01

Full Text Available An investigation into the biopharmaceutics classification and a study of the in vitro bioavailability (permeability and solubility of the antiviral compound enisamium iodide (4-(benzylcarbamoyl-1-methylpyridinium iodide were carried out. The solubility of enisamium iodide was determined in four different buffers. Apparent intestinal permeability (Papp of enisamium iodide was assessed using human colon carcinoma (Caco-2 cells at three concentrations. The solubility of enisamium iodide in four buffer solutions from pH 1.2 to 7.5 is about 60 mg/mL at 25 °C, and ranges from 130 to 150 mg/mL at 37 °C, depending on the pH. Based on these results, enisamium iodide can be classified as highly soluble. Enisamium iodide demonstrated low permeability in Caco-2 experiments in all tested concentrations of 10–100 μM with permeability coefficients between 0.2 × 10−6 cm s−1 and 0.3 × 10−6 cm s−1. These results indicate that enisamium iodide belongs to class III of the Biopharmaceutics Classification System (BCS due to its high solubility and low permeability. The bioavailability of enisamium iodide needs to be confirmed in animal and human studies.

Milk-alkali syndrome

Science.gov (United States)

Calcium-alkali syndrome; Cope syndrome; Burnett syndrome; Hypercalcemia; Calcium metabolism disorder ... Milk-alkali syndrome is almost always caused by taking too many calcium supplements, usually in the form of calcium carbonate. Calcium ...

Study of radiation formation of methyl-iodide Part 2

International Nuclear Information System (INIS)

Bartonicek, B.; Schweiner, Z.; Bednar, J.; Hladky, E.

1975-01-01

Purified methane, ethylene, iodine, methyl iodide, ethyl iodide and hydrogen iodide were irradiated and/or pyrolyzed in Pyrex ampoules by 60 Co-γ-radiation at temperatures between 150 and 450 deg C. The results on radiolysis and pyrolysis were as follows: 1., The most thermally stable product is hydrogen iodide in which already at 450 deg C essen-tially all originally present iodine appears. 2., The radiolytic formation of methyl iodide and hydrogen iodide is positively influenced by the rise in temperature, This and the absolute values of yields indicate a chain mechanism of radiolytic (and pyrolytic) decomposition of the mixture. 3., The ratio of equilibrium concentrations [HI]/[CH 3 I] increases with increasing temperature of pyrolysis showing that HI is the end product of the thermal chain reaction. Methyl iodide is likely to contribute (by its thermal decomposition) to the initiation and propagation of this chain reaction. 4., The negligible temperature dependence of G(H 2 ) and the absence of molecular hydrogen among the products of pyrolytic decomposition of methane-iodine mixtures shows, that (up to 450 deg C) H atoms do not play any role in the thermal chain decomposition of these mixtures. (K.A.)

The effect of potassium iodide on the production of acid phosphatase by Sporothrix schenckii

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P. S. Grover

2003-06-01

Full Text Available The present study was undertaken to find out the in vitro effect of potassium iodide (KI on the production of acid phosphatase by fully characterized strain of S.schenckii isolated from a patient of Cutaneous Sporotrichosis. The enzyme acid phosphatase was estimated during the 3 phases of growth of S.schenckii, without and with three concentrations of KI incorporated in the culture medium. In the control and in the test proper, with various concentrations of KI, no adverse effect of KI was observed on the production of acid phosphatase in early and mid log phase of fungal growth. Whereas in the exponential phase in test proper, there was a statistical significant decrease in the enzyme production with 0.8% and 3.2% of KI. The low activity at 0.8% and 3.2% KI indicates that KI has inhibitory effect on the growth of S.schenckii and has led to decrease in the activity of the enzyme. (Med J Indones 2003; 12: 65-8 Keywords: S.schenckii, acid phosphatase, potassium iodide

Liquid alkali metals and alkali-based alloys as electron-ion plasmas

International Nuclear Information System (INIS)

Tosi, M.P.

1981-06-01

The article reviews the theory of thermodynamic and structural properties of liquid alkali metals and alkali-based alloys, within the framework of linear screening theory for the electron-ion interactions. (author)

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)

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

Experimental study on iodine chemistry (EXSI) - Containment experiments with methyl iodide

Energy Technology Data Exchange (ETDEWEB)

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

2010-05-15

An experimental study on radiolytic decomposition of methyl iodide was conducted in co-operation between VTT and Chalmers University of Technology as a part of the NKS-R programs. 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. In year 2008 the NROI project, a Nordic collaboration studying iodine chemistry in the containment was started. During 2009, oxidation of iodine, especially organic iodine, was studied within the NROI project. The chemistry of organic iodine in the gas phase is still one of the greatest remaining uncertainties concerning iodine behaviour during a severe accident. During the first year of the NROI project the oxidation of elemental iodine, I2, with ozone and UV-light was investigated. In this study organic iodide, in this case methyl iodide, was investigated in similar conditions as in the NROI-1 project. The experimental facility applied in this study is based on the sampling system built at VTT for the ISTP project CHIP conducted by 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. Experimental results showed that the methyl iodide concentration in the facility was reduced with increasing temperature and increasing UVC intensity. Similar behaviour occurred when ozone was present in the system. Formed organic gas species during the decomposition of methyl iodide was mainly formaldehyde and methanol. Instant and extensive particle formation occurred when methyl iodide was transported through a UVC radiation field and/or when ozone was present. The size of the formed primary particles was about 10 nm and the size of secondary particles was between 50-150 nm. From the SEM-EDX analyses of the particles, the conclusion was drawn that these were some kind of iodine

Experimental study on iodine chemistry (EXSI) - Containment experiments with methyl iodide

International Nuclear Information System (INIS)

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

2010-05-01

An experimental study on radiolytic decomposition of methyl iodide was conducted in co-operation between VTT and Chalmers University of Technology as a part of the NKS-R programs. 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. In year 2008 the NROI project, a Nordic collaboration studying iodine chemistry in the containment was started. During 2009, oxidation of iodine, especially organic iodine, was studied within the NROI project. The chemistry of organic iodine in the gas phase is still one of the greatest remaining uncertainties concerning iodine behaviour during a severe accident. During the first year of the NROI project the oxidation of elemental iodine, I2, with ozone and UV-light was investigated. In this study organic iodide, in this case methyl iodide, was investigated in similar conditions as in the NROI-1 project. The experimental facility applied in this study is based on the sampling system built at VTT for the ISTP project CHIP conducted by 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. Experimental results showed that the methyl iodide concentration in the facility was reduced with increasing temperature and increasing UVC intensity. Similar behaviour occurred when ozone was present in the system. Formed organic gas species during the decomposition of methyl iodide was mainly formaldehyde and methanol. Instant and extensive particle formation occurred when methyl iodide was transported through a UVC radiation field and/or when ozone was present. The size of the formed primary particles was about 10 nm and the size of secondary particles was between 50-150 nm. From the SEM-EDX analyses of the particles, the conclusion was drawn that these were some kind of iodine

Mechanical Behaviour of Soil Improved by Alkali Activated Binders

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Enza Vitale

2017-11-01

Full Text Available The use of alkali activated binders to improve engineering properties of clayey soils is a novel solution, and an alternative to the widely diffused improvement based on the use of traditional binders such as lime and cement. In the paper the alkaline activation of two fly ashes, by-products of coal combustion thermoelectric power plants, has been presented. These alkali activated binders have been mixed with a clayey soil for evaluating the improvement of its mechanical behaviour. One-dimensional compression tests on raw and treated samples have been performed with reference to the effects induced by type of binder, binder contents and curing time. The experimental evidences at volume scale of the treated samples have been directly linked to the chemo-physical evolution of the binders, investigated over curing time by means of X Ray Diffraction. Test results showed a high reactivity of the alkali activated binders promoting the formation of new mineralogical phases responsible for the mechanical improvement of treated soil. The efficiency of alkali activated binders soil treatment has been highlighted by comparison with mechanical performance induced by Portland cement.

Characterisation and properties of alkali activated pozzolanic materials

Science.gov (United States)

Bordeian, Georgeta Simona

: density, water absorption, apparent porosity and coefficient of saturation, drying shrinkage, compressive creep, compressive, flexural and tensile splitting strength, dynamic modulus of elasticity, accelerated weathering (freeze-thaw cycle) resistance, fire resistance (temperatures up to 600°C), microstructure, macrostructure and investigation of hydration phases by SEM, ED AX, Digital-mapping and X-ray diffraction.The influence of key parameters e.g. slag content, curing method, water/binder ratio and water glass hardener content on the mechanical properties were determined. Optimisation of the alkali-activation of fly ash materials was achieved by blending this with other pozzolans such as silica fume and slags. Mechanical properties were further improved by using moulding pressures and by thermal treatment. The use of short fibre reinforcements was investigated to overcome microcracking, volumetric deformation and creep in the materials. The free shrinkage and creep of the materials agree with the model developed by Mangat and Azari for fibre reinforced Portland cement composites. Other additives were also investigated to improve workability, frost and water resistance and physical properties of the alkali activated materials. The fundamental relationships between chemical composition, hydration phases,microstructure and engineering properties (strength, durability and stability) of alkali activated materials were investigated. It is clear that strength development is a function of the hydration products developed and these are affected by the mix composition and the curing temperature. The current work found parameters such as the Si/Al ratio, the Ca/Si ratio and the Na20 content to be important. These chemical parameters decide the principal phases in the hydration products formed in alkali activated materials, between calcium silicate hydrate (C-S-H) and zeolite of the form (R[2]0 n Al[2]O[3] x SiO[2] r H[2]O).Overall the thesis shows the great potential of alkali

Methods of recovering alkali metals

Science.gov (United States)

Krumhansl, James L; Rigali, Mark J

2014-03-04

Approaches for alkali metal extraction, sequestration and recovery are described. For example, a method of recovering alkali metals includes providing a CST or CST-like (e.g., small pore zeolite) material. The alkali metal species is scavenged from the liquid mixture by the CST or CST-like material. The alkali metal species is extracted from the CST or CST-like material.

Linking loss of sodium-iodide symporter expression to DNA damage

Energy Technology Data Exchange (ETDEWEB)

Lyckesvärd, Madeleine Nordén [Sahlgrenska Cancer Center, University of Gothenburg, Göteborg (Sweden); Department of Medical Chemistry and Cell Biology, University of Gothenburg, Göteborg (Sweden); Kapoor, Nirmal [Department of Medical Chemistry and Cell Biology, University of Gothenburg, Göteborg (Sweden); Ingeson-Carlsson, Camilla; Carlsson, Therese [Sahlgrenska Cancer Center, University of Gothenburg, Göteborg (Sweden); Department of Medical Chemistry and Cell Biology, University of Gothenburg, Göteborg (Sweden); Karlsson, Jan-Olof [Department of Medical Chemistry and Cell Biology, University of Gothenburg, Göteborg (Sweden); Postgård, Per; Himmelman, Jakob; Forssell-Aronsson, Eva [Department of Radiation Physics, University of Gothenburg, Göteborg (Sweden); Hammarsten, Ola [Department of Clinical Chemistry, University of Gothenburg, Göteborg (Sweden); Nilsson, Mikael, E-mail: mikael.nilsson@gu.se [Sahlgrenska Cancer Center, University of Gothenburg, Göteborg (Sweden); Department of Medical Chemistry and Cell Biology, University of Gothenburg, Göteborg (Sweden)

2016-05-15

Radiotherapy of thyroid cancer with I-131 is abrogated by inherent loss of radioiodine uptake due to loss of sodium iodide symporter (NIS) expression in poorly differentiated tumor cells. It is also known that ionizing radiation per se down-regulates NIS (the stunning effect), but the mechanism is unknown. Here we investigated whether loss of NIS-mediated iodide transport may be elicited by DNA damage. Calicheamicin, a fungal toxin that specifically cleaves double-stranded DNA, induced a full scale DNA damage response mediated by the ataxia-telangiectasia mutated (ATM) kinase in quiescent normal thyrocytes. At sublethal concentrations (<1 nM) calicheamicin blocked NIS mRNA expression and transepithelial iodide transport as stimulated by thyrotropin; loss of function occurred at a much faster rate than after I-131 irradiation. KU-55933, a selective ATM kinase inhibitor, partly rescued NIS expression and iodide transport in DNA-damaged cells. Prolonged ATM inhibition in healthy cells also repressed NIS-mediated iodide transport. ATM-dependent loss of iodide transport was counteracted by IGF-1. Together, these findings indicate that NIS, the major iodide transporter of the thyroid gland, is susceptible to DNA damage involving ATM-mediated mechanisms. This uncovers novel means of poor radioiodine uptake in thyroid cells subjected to extrinsic or intrinsic genotoxic stress. - Highlights: • DNA damage inhibits polarized iodide transport in normal thyroid cells. • Down-regulation of NIS expression is mediated by activation of the ATM kinase. • Long-term ATM inhibition also represses NIS-mediated iodide transport. • IGF-1 rescues NIS expression and iodide transport in DNA-damaged cells.

Linking loss of sodium-iodide symporter expression to DNA damage

International Nuclear Information System (INIS)

Lyckesvärd, Madeleine Nordén; Kapoor, Nirmal; Ingeson-Carlsson, Camilla; Carlsson, Therese; Karlsson, Jan-Olof; Postgård, Per; Himmelman, Jakob; Forssell-Aronsson, Eva; Hammarsten, Ola; Nilsson, Mikael

2016-01-01

Radiotherapy of thyroid cancer with I-131 is abrogated by inherent loss of radioiodine uptake due to loss of sodium iodide symporter (NIS) expression in poorly differentiated tumor cells. It is also known that ionizing radiation per se down-regulates NIS (the stunning effect), but the mechanism is unknown. Here we investigated whether loss of NIS-mediated iodide transport may be elicited by DNA damage. Calicheamicin, a fungal toxin that specifically cleaves double-stranded DNA, induced a full scale DNA damage response mediated by the ataxia-telangiectasia mutated (ATM) kinase in quiescent normal thyrocytes. At sublethal concentrations (<1 nM) calicheamicin blocked NIS mRNA expression and transepithelial iodide transport as stimulated by thyrotropin; loss of function occurred at a much faster rate than after I-131 irradiation. KU-55933, a selective ATM kinase inhibitor, partly rescued NIS expression and iodide transport in DNA-damaged cells. Prolonged ATM inhibition in healthy cells also repressed NIS-mediated iodide transport. ATM-dependent loss of iodide transport was counteracted by IGF-1. Together, these findings indicate that NIS, the major iodide transporter of the thyroid gland, is susceptible to DNA damage involving ATM-mediated mechanisms. This uncovers novel means of poor radioiodine uptake in thyroid cells subjected to extrinsic or intrinsic genotoxic stress. - Highlights: • DNA damage inhibits polarized iodide transport in normal thyroid cells. • Down-regulation of NIS expression is mediated by activation of the ATM kinase. • Long-term ATM inhibition also represses NIS-mediated iodide transport. • IGF-1 rescues NIS expression and iodide transport in DNA-damaged cells.

Alkali-vapor laser-excimer pumped alkali laser

International Nuclear Information System (INIS)

Yue Desheng; Li Wenyu; Wang Hongyan; Yang Zining; Xu Xiaojun

2012-01-01

Based on the research internal and overseas, the principle of the excimer pumped alkali laser (XPAL) is explained, and the advantages and disadvantages of the XPAL are analyzed. Taking into consideration the difficulties that the diode pumped alkali laser (DPAL) meets on its development, the ability to solve or avoid these difficulties of XPAL is also analyzed. By summing up the achievements of the XPAL, the possible further prospect is proposed. The XPAL is of possibility to improve the performance of the DPAL. (authors)

Alkali metal ion battery with bimetallic electrode

Science.gov (United States)

Boysen, Dane A; Bradwell, David J; Jiang, Kai; Kim, Hojong; Ortiz, Luis A; Sadoway, Donald R; Tomaszowska, Alina A; Wei, Weifeng; Wang, Kangli

2015-04-07

Electrochemical cells having molten electrodes having an alkali metal provide receipt and delivery of power by transporting atoms of the alkali metal between electrode environments of disparate chemical potentials through an electrochemical pathway comprising a salt of the alkali metal. The chemical potential of the alkali metal is decreased when combined with one or more non-alkali metals, thus producing a voltage between an electrode comprising the molten the alkali metal and the electrode comprising the combined alkali/non-alkali metals.

Iodide behaviour in hard clay rocks under controlled physico-chemical conditions at different concentrations

International Nuclear Information System (INIS)

Frasca, B.; Savoye, S.; Wittebroodt, C.; Leupin, O.X.; Descostes, M.; Grenut, B.; Meier, P.; Michelot, J.L.

2010-01-01

Document available in extended abstract form only. With a half-life of 1.6 10 7 years, its high mobility and its potential to accumulate in the biosphere, iodine-129 is considered, from safety assessment calculations for radioactive waste repositories, to be one of the main radiological dose contributors. Based on the findings of previous studies, iodide, especially at low concentrations, seems to be migrating at a slower rate in clay rock than Cl-36. The cause of this retardation regarding the diffusion of iodide versus chloride is not yet understood but several hypotheses are point towards sorption on natural organic matter (NOM), pyrite or redox reactions. Oxidation of iodide would form IO 3 - which is known to have a higher sorption affinity on several soils and sediment samples than iodide. The present project aims at exploring the effect on the iodide behaviour of two parameters: (i) the initial concentration of iodide and (ii) the amount of NOM contained in the argillite samples. Such an investigation is carried out on Tournemire argillite by means of both batch and through-diffusion experiments. The main challenge is to exclude as much as possible the occurrence of any experimental artefact that could induce iodide uptake (oxygen contamination, dissolution/precipitation of carbonate phases). Regarding redox conditions and rock equilibrium, all the experiments were carried out under physico-chemical conditions as close as possible to those prevailing in field. Using a glove box with an atmosphere of N 2 /CO 2 (respectively 99.6% and 0.4%), we preserved the experiments from oxygen and maintained the calculated in-situ carbonate equilibrium. At first, four through-diffusion experiments with the non-sorbing tracers HTO and Cl-36 were performed to allow the diffusive parameters of each sample to be defined. Afterwards, iodide was injected in the diffusion cells at four different concentrations (10 -6 M to 10 -3 M). Thus, the comparison of the incoming fluxes of

Application of chemical methods to assess the mechanism of alkali activation in low calcium fly ash

Energy Technology Data Exchange (ETDEWEB)

Arjunan, P.; Silsbee, M.R.; Roy, D.M. [Pennsylvania State Univ., PA (United States). Materials Research Lab.

1999-11-01

A better understanding of the amount of fly ash unreacted remaining after alkali activation of low calcium fly ash is necessary for elucidating the underlying alkali activation mechanism. An approach to this determination is reported in this study which utilizes an ethylenediamine tetraacetic acid/triethanolamine/NaOH mixture to determine the unreacted fly ash particles present in an OPC-low calcium fly ash mixture, with and without alkali activation. This study also uses another chemical technique called orthophosphoric acid dissolution method to assess the amount of unreacted crystalline phases present in hydrated OPC-ash mixtures at different ages of hydration. The information obtained from these two chemical techniques was used to identify the nature of unreacted fly ash particles present in the hydrated samples. The amount of unreacted fly ash and the compressive strength data were correlated to assess the extent of influence of alkali activation on the reactivity of the amorphous and crystalline phase content of the low calcium fly ash.

Alkali pH directly activates ATP-sensitive K+ channels and inhibits insulin secretion in beta-cells.

Science.gov (United States)

Manning Fox, Jocelyn E; Karaman, Gunce; Wheeler, Michael B

2006-11-17

Glucose stimulation of pancreatic beta-cells is reported to lead to sustained alkalization, while extracellular application of weak bases is reported to inhibit electrical activity and decrease insulin secretion. We hypothesize that beta-cell K(ATP) channel activity is modulated by alkaline pH. Using the excised patch-clamp technique, we demonstrate a direct stimulatory action of alkali pH on recombinant SUR1/Kir6.2 channels due to increased open probability. Bath application of alkali pH similarly activates native islet beta-cell K(ATP) channels, leading to an inhibition of action potentials, and hyperpolarization of membrane potential. In situ pancreatic perfusion confirms that these cellular effects of alkali pH are observable at a functional level, resulting in decreases in both phase 1 and phase 2 glucose-stimulated insulin secretion. Our data are the first to report a stimulatory effect of a range of alkali pH on K(ATP) channel activity and link this to downstream effects on islet beta-cell function.

Potassium iodide capsule treatment of feline sporotrichosis.

Science.gov (United States)

Reis, Erica G; Gremião, Isabella D F; Kitada, Amanda A B; Rocha, Raphael F D B; Castro, Verônica S P; Barros, Mônica B L; Menezes, Rodrigo C; Pereira, Sandro A; Schubach, Tânia M P

2012-06-01

Sporotrichosis is a mycosis caused by Sporothrix schenckii. The most affected animal is the cat; it has played an important role in the zoonotic transmission of this disease, especially in Rio de Janeiro, Brazil, since 1998. In order to evaluate the treatment of feline sporotrichosis with potassium iodide, an observational cohort was conducted in 48 cats with sporotrichosis at Instituto de Pesquisa Clínica Evandro Chagas, Fiocruz. All cats received potassium iodide capsules, 2.5 mg/kg to 20 mg/kg q24h. The cure rate was 47.9%, treatment failure was 37.5%, treatment abandonment was 10.4% and death was 4.2%. Clinical adverse effects were observed in 52.1% of the cases. Thirteen cats had a mild increase in hepatic transaminase levels during the treatment, six of them presented clinical signs suggestive of hepatotoxicity. Compared to previous studies with itraconazole and iodide in saturated solution, potassium iodide capsules are an alternative for feline sporotrichosis treatment.

Alkali-iodide/urania systems at high temperatures. 1. Cesium uranate chemistry

International Nuclear Information System (INIS)

McFarlane, J.; LeBlanc, J.C.

1994-09-01

Uranate compounds are likely to form in irradiated fuel from the reaction between UO 2 and fission products along UO 2 grain boundaries and in the fuel-cladding gap. Literature on the high-temperature chemistry of cesium and rubidium uranates was reviewed. Results from Knudsen cell experiments from 900 to 2600 K on cesium uranates are discussed. These studies indicate that the uranate phases formed depend on the oxygen potential of the system, which varies with the composition of the condensed phase. 62 refs., 12 figs., 6 tabs., 2 appendices

POTENTIAL MODIFICATION OF HYDRATION OF ALKALI ACTIVATED MIXTURES FROM GRANULATED BLAST FURNACE SLAG AND FLY ASH

Directory of Open Access Journals (Sweden)

VÁCLAVA TOMKOVÁ

2012-07-01

Full Text Available Alkali activated binders (AAB and composites from suitable latent hydraulic raw materials represent an alternative to materials based on Portland cements. The paper deals with possibilities to influence functional parameters of AAB by setting the mixtures of GBFS and fly ash to the selected chemical composition or by fly ash reactivity change effected by milling. In this way course of hydration process is modified, the alkali activation products phase composition is changed as well as their final characteristic. The amorphous character of the hydration products limits the evaluation of the composition during the massing phase. Part of the study is the search for possibilities of identifying the differences in composition and properties of specially drafted mixtures of original raw materials after their alkali activation.

Alkali resistant optical coatings for alkali lasers and methods of production thereof

Science.gov (United States)

Soules, Thomas F; Beach, Raymond J; Mitchell, Scott C

2014-11-18

In one embodiment, a multilayer dielectric coating for use in an alkali laser includes two or more alternating layers of high and low refractive index materials, wherein an innermost layer includes a thicker, >500 nm, and dense, >97% of theoretical, layer of at least one of: alumina, zirconia, and hafnia for protecting subsequent layers of the two or more alternating layers of high and low index dielectric materials from alkali attack. In another embodiment, a method for forming an alkali resistant coating includes forming a first oxide material above a substrate and forming a second oxide material above the first oxide material to form a multilayer dielectric coating, wherein the second oxide material is on a side of the multilayer dielectric coating for contacting an alkali.

Prevention of organic iodide formation in BWR`s

Energy Technology Data Exchange (ETDEWEB)

Karjunen, T [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland); Laitinen, T; Piippo, J; Sirkiae, P [VTT Manufacturing Technology (Finland)

1996-12-01

During an accident, many different forms of iodine may emerge. Organic iodides, such as methyl iodide and ethyl iodide, are relatively volatile, and thus their appearance leads to increased concentration of gaseous iodine. Since organic iodides are also relatively immune to most accident mitigation measures, such as sprays and filters, they can affect the accident source term significantly even when only a small portion of iodine is in organic form. Formation of organic iodides may not be limited by the amount of organic substances available. Excessive amounts of methane can be produced, for example, during oxidation of boron carbide, which is used in BWR`s as a neutron absorber material. Another important source is cable insulation. In a BWR, a large quantity of cables is placed below the pressure vessel. Thus a large quantity of pyrolyse gases will be produced, should the vessel fail. Organic iodides can be formed as a result of many different reactions, but at least in certain conditions the main reaction takes place between an organic radical produced by radiolysis and elemental iodine. A necessary requirement for prevention of organic iodide production is therefore that the pH in the containment water pools is kept high enough to eliminate formation of elemental iodine. In a typical BWR the suppression pool water is usually unbuffered. As a result, the pH may be dominated by chemicals introduced during an accident. If no system for adding basic chemicals is operable, the main factor affecting pool water pH may be hydrochloric acid released during cable degradation. Should this occur, the conditions could be very favorable for production of elemental iodine and, consequently, formation of organic iodides. Although high pH is necessary for iodine retention, it could have also adverse effects. High pH may, for example, accelerate corrosion of containment materials and alter the characteristics of the solid corrosion products. (author) 6 figs., 1 tab., 13 refs.

Alkali metal and alkali metal hydroxide intercalates of the layered transition metal disulfides

International Nuclear Information System (INIS)

Kanzaki, Y.; Konuma, M.; Matsumoto, O.

1981-01-01

The intercalation reaction of some layered transition metal disulfides with alkali metals, alkali metal hydroxides, and tetraalkylammonium hydroxides were investigated. The alkali metal intercalates were prepared in the respective metal-hexamethylphosphoric triamide solutions in vaccuo, and the hydroxide intercalates in aqueous hydroxide solutions. According to the intercalation reaction, the c-lattice parameter was increased, and the increase indicated the expansion of the interlayer distance. In the case of alkali metal intercalates, the expansion of the interlayer distance increased continuously, corresponding to the atomic radius of the alkali metal. On the other hand, the hydroxide intercalates showed discrete expansion corresponding to the effective ionic radius of the intercalated cation. All intercalates of TaS 2 amd NbS 2 were superconductors. The expansion of the interlayer distance tended to increase the superconducting transition temperature in the intercalates of TaS 2 and vice versa in those of NbS 2 . (orig.)

Alteration of alkali reactive aggregates autoclaved in different alkali solutions and application to alkali-aggregate reaction in concrete (II) expansion and microstructure of concrete microbar

International Nuclear Information System (INIS)

Lu Duyou; Mei Laibao; Xu Zhongzi; Tang Mingshu; Mo Xiangyin; Fournier, Benoit

2006-01-01

The effect of the type of alkalis on the expansion behavior of concrete microbars containing typical aggregate with alkali-silica reactivity and alkali-carbonate reactivity was studied. The results verified that: (1) at the same molar concentration, sodium has the strongest contribution to expansion due to both ASR and ACR, followed by potassium and lithium; (2) sufficient LiOH can completely suppress expansion due to ASR whereas it can induce expansion due to ACR. It is possible to use the duplex effect of LiOH on ASR and ACR to clarify the ACR contribution when ASR and ACR may coexist. It has been shown that a small amount of dolomite in the fine-grained siliceous Spratt limestone, which has always been used as a reference aggregate for high alkali-silica reactivity, might dedolomitize in alkaline environment and contribute to the expansion. That is to say, Spratt limestone may exhibit both alkali-silica and alkali-carbonate reactivity, although alkali-silica reactivity is predominant. Microstructural study suggested that the mechanism in which lithium controls ASR expansion is mainly due to the favorable formation of lithium-containing less-expansive product around aggregate particles and the protection of the reactive aggregate from further attack by alkalis by the lithium-containing product layer

ALKALI FUSION OF ROSETTA ZIRCON

International Nuclear Information System (INIS)

DAHER, A.

2008-01-01

The decomposition of Rosetta zircon by fusion with different types of alkalis has been investigated. These alkalis include sodium hydroxide, potassium hydroxide and eutectic mixture of both. The influences of the reaction temperature, zircon to alkalis ratio, fusion time and the stirring of the reactant on the fusion reaction have been evaluated. The obtained results favour the decomposition of zircon with the eutectic alkalis mixture by a decomposition efficiency of 96% obtained at 500 0 C after one hour

The Role of Connectivity on Electronic Properties of Lead Iodide Perovskite-Derived Compounds

NARCIS (Netherlands)

Kamminga, Machteld E; De Wijs, Gilles; Havenith, Remco W A; Blake, Graeme R; Palstra, Thomas T M

2017-01-01

We use a layered solution crystal growth method to synthesize high-quality single crystals of two different benzylammonium lead iodide perovskite-like organic/inorganic hybrids. The well-known (C6H5CH2NH3)(2)PbI4 phase is obtained in the form of bright orange platelets, with a structure comprised of

Dual Alkali Solvent System for CO2 Capture from Flue Gas.

Science.gov (United States)

Li, Yang; Wang, H Paul; Liao, Chang-Yu; Zhao, Xinglei; Hsiung, Tung-Li; Liu, Shou-Heng; Chang, Shih-Ger

2017-08-01

A novel two-aqueous-phase CO 2 capture system, namely the dual alkali solvent (DAS) system, has been developed. Unlike traditional solvent-based CO 2 capture systems in which the same solvent is used for both CO 2 absorption and stripping, the solvent of the DAS system consists of two aqueous phases. The upper phase, which contains an organic alkali 1-(2-hydroxyethyl) piperazine (HEP), is used for CO 2 absorption. The lower phase, which consists of a mixture of K 2 CO 3 /KHCO 3 aqueous solution and KHCO 3 precipitate, is used for CO 2 stripping. Only a certain kind of amine (such as HEP) is able to ensure the phase separation, satisfactory absorption efficiency, effective CO 2 transfer from the upper phase to the lower phase, and regeneration of the upper phase. In the meantime, due to the presence of K 2 CO 3 /KHCO 3 in the lower phase, HEP in the upper phase is capable of being regenerated from its sulfite/sulfate heat stable salt, which enables the simultaneous absorption of CO 2 and SO 2 /SO 3 from the flue gas. Preliminary experiments and simulations indicate that the implementation of the DAS system can lead to 24.0% stripping energy savings compared to the Econamine process, without significantly lowering the CO 2 absorption efficiency (∼90%).

O-alkylation of disodium salt of diethyl 3,4-dihydroxythiophene-2,5-dicarboxylate with 1,2-dichloroethane catalyzed by ionic type phase transfer catalyst and potassium iodide

Energy Technology Data Exchange (ETDEWEB)

Lu, Huasheng; Yin, Hengbo; Wang, Aili; Shen, Jun; Yan, Xiaobo; Liu, Yumin; Zhang, Changhua [Jiangsu University, Zhenjiang (China)

2014-01-15

Diethyl 3,4-ethylenedioxy thiophene-2,5-dicarboxylate was efficiently synthesized via the O-alkylation of disodium salt of diethyl 3,4-dihydroxy thiophene-2,5-dicarboxylate with 1,2-dichloroethane over ionic type phase transfer catalysts, such as tetrabutyl ammonium bromide and benzyl triethyl ammonium chloride. The ionic type phase transfer catalysts showed higher catalytic activities than the nonionic type phase transfer catalysts, such as triethylamine, pyridine, 18-crown-6, and polyethylene glycol 400/600, in the O-alkylation reaction. The conversion of the disodium salt of more than 97% and the selectivity of diethyl 3,4-ethylenedioxy thiophene-2,5-dicarboxylate of more than 98% were achieved when the O-alkylation reaction was synergistically catalyzed by tetrabutyl ammonium bromide and potassium iodide.

Kinetics of [123I]iodide uptake and discharge by perchlorate in studies of inhibition of iodide binding by antithyroid drugs

International Nuclear Information System (INIS)

McCruden, D.C.; Connell, J.M.C.; Alexander, W.D.; Hilditch, T.E.

1985-01-01

Thyroidal binding of iodide was studied by kinetic analysis of [ 123 ]iodide uptake and its discharge by perchlorate in 80 hyperthyroid subjects receiving antithyroid drug therapy. Five dosage regimens ranging from 5 mg carbimazole twice daily to 15 mg methimazole twice daily were studied. Binding inhibition was estimated at 5-7 h after drug as an index of the mean effect of the 12 hourly regimen. In all cases, except one in the lowest dose group, binding was found to be markedly reduced with mean binding rates ranging from 0.002 to 0.020 min -1 (normal > 0.15 min -1 ). The net clearance of iodide in the lowest dose group was reduced to a mean value near the upper limit of the euthyroid range, whereas in the highest dose group it lay at the lower limit of the euthyroid range. These results were reflected in the serum thyroid hormone response. There was a reducing incidence of inadequate control of hyperthyroidism and an increasing incidence of hypothyroidism with increasing thiourylene dose. The exit rate constant of free iodide for the various doses showed values from 0.048 to 0.055 min -1 . Correpsonding mean values for the discharge rate constant after perchlorate were 0.087 to 0.105 min -1 . This suggests that perchlorate increases the rate of iodide release from the thyroid gland. Studies at a later interval after drug (12-14 h) showed no change in discharge rate constant. This leads to the conclusion that perchlorate may further inhibit iodide binding in subjects receiving antithyroid drug therapy. (author)

Alkali metal for ultraviolet band-pass filter

Science.gov (United States)

Mardesich, Nick (Inventor); Fraschetti, George A. (Inventor); Mccann, Timothy A. (Inventor); Mayall, Sherwood D. (Inventor); Dunn, Donald E. (Inventor); Trauger, John T. (Inventor)

1993-01-01

An alkali metal filter having a layer of metallic bismuth deposited onto the alkali metal is provided. The metallic bismuth acts to stabilize the surface of the alkali metal to prevent substantial surface migration from occurring on the alkali metal, which may degrade optical characteristics of the filter. To this end, a layer of metallic bismuth is deposited by vapor deposition over the alkali metal to a depth of approximately 5 to 10 A. A complete alkali metal filter is described along with a method for fabricating the alkali metal filter.

Flavonoids, Thyroid Iodide Uptake and Thyroid Cancer-A Review.

Science.gov (United States)

Gonçalves, Carlos F L; de Freitas, Mariana L; Ferreira, Andrea C F

2017-06-12

Thyroid cancer is the most common malignant tumor of the endocrine system and the incidence has been increasing in recent years. In a great part of the differentiated carcinomas, thyrocytes are capable of uptaking iodide. In these cases, the main therapeutic approach includes thyroidectomy followed by ablative therapy with radioiodine. However, in part of the patients, the capacity to concentrate iodide is lost due to down-regulation of the sodium-iodide symporter (NIS), the protein responsible for transporting iodide into the thyrocytes. Thus, therapy with radioiodide becomes ineffective, limiting therapeutic options and reducing the life expectancy of the patient. Excessive ingestion of some flavonoids has been associated with thyroid dysfunction and goiter. Nevertheless, studies have shown that some flavonoids can be beneficial for thyroid cancer, by reducing cell proliferation and increasing cell death, besides increasing NIS mRNA levels and iodide uptake. Recent data show that the flavonoids apingenin and rutin are capable of increasing NIS function and expression in vivo. Herein we review literature data regarding the effect of flavonoids on thyroid cancer, besides the effect of these compounds on the expression and function of the sodium-iodide symporter. We will also discuss the possibility of using flavonoids as adjuvants for therapy of thyroid cancer.

Flavonoids, Thyroid Iodide Uptake and Thyroid Cancer—A Review

Science.gov (United States)

Gonçalves, Carlos F. L.; de Freitas, Mariana L.; Ferreira, Andrea C. F.

2017-01-01

Thyroid cancer is the most common malignant tumor of the endocrine system and the incidence has been increasing in recent years. In a great part of the differentiated carcinomas, thyrocytes are capable of uptaking iodide. In these cases, the main therapeutic approach includes thyroidectomy followed by ablative therapy with radioiodine. However, in part of the patients, the capacity to concentrate iodide is lost due to down-regulation of the sodium-iodide symporter (NIS), the protein responsible for transporting iodide into the thyrocytes. Thus, therapy with radioiodide becomes ineffective, limiting therapeutic options and reducing the life expectancy of the patient. Excessive ingestion of some flavonoids has been associated with thyroid dysfunction and goiter. Nevertheless, studies have shown that some flavonoids can be beneficial for thyroid cancer, by reducing cell proliferation and increasing cell death, besides increasing NIS mRNA levels and iodide uptake. Recent data show that the flavonoids apingenin and rutin are capable of increasing NIS function and expression in vivo. Herein we review literature data regarding the effect of flavonoids on thyroid cancer, besides the effect of these compounds on the expression and function of the sodium-iodide symporter. We will also discuss the possibility of using flavonoids as adjuvants for therapy of thyroid cancer. PMID:28604619

Performance of iodide vapour absorption in the venturi scrubber working in self-priming mode

International Nuclear Information System (INIS)

Zhou, Yanmin; Sun, Zhongning; Gu, Haifeng; Miao, Zhuang

2016-01-01

Highlights: • The absorption performance for iodide vapour was studied under different conditions. • A mathematical model was developed to describe the iodide absorption process. • The venturi scrubber can ensure absorption efficiiency and reduce pressure loss. - Abstract: The self-priming venturi scrubber is the key component of filtered containment venting systems for the removal of radioactive products during severe accidents in nuclear power plants. This paper is focused on the absorption performance of iodide vapour in the venturi scrubber, based on experiment and mathematical calculation. The results indicate that the absorption efficiency is closely related to solution flow rate, gas flow rate and temperature, but is not sensitive to iodide inlet concentration. When solution flow rate is low, the absorption efficiency increases rapidly with increasing the solution flow rate, and when the solution is excessive, the absorption efficiency remains around 99% stably; the influence of gas flow rate on absorption efficiency is mainly reflected in the variation of gas and liquid contacting time; when the solution flow rate is low, the increase of gas flow rate will led to an obvious decrease in absorption efficiency; temperature is not important when gas flow rate in constant but becomes effective for improving the absorption efficiency when gas velocity is constant. The proposed mathematical model can predict the iodide absorption process well in the range of experimental conditions. Especially, in the condition of lower gas flow rate and higher solution flow rate, the prediction accuracy is more satisfactory; however the accuracy of prediction will decrease at higher gas flow rates and lower solution flow rates because of neglecting the transverse exchange between gas and liquid phase.

Photoluminescence Enhancement in Formamidinium Lead Iodide Thin Films

NARCIS (Netherlands)

Fang, Hong-Hua; Wang, Feng; Adjokatse, Sampson; Zhao, Ni; Loi, Maria Antonietta

2016-01-01

Formamidinium lead iodide (FAPbI(3)) has a broader absorption spectrum and better thermal stability than the most famous methylammonium lead iodide, thus exhibiting great potential for photovoltaic applications. In this report, the light-induced photoluminescence (PL) evolution in FAPbI(3) thin

Comparative study of reversible hydrogen storage in alkali-doped fulleranes

Energy Technology Data Exchange (ETDEWEB)

Teprovich, Joseph A.; Knight, Douglas A.; Peters, Brent [Clean Energy Directorate – Savannah River National Laboratory, Aiken, SC 29801 (United States); Zidan, Ragaiy, E-mail: ragaiy.zidan@srnl.doe.gov [Clean Energy Directorate – Savannah River National Laboratory, Aiken, SC 29801 (United States)

2013-12-15

Highlights: ► Catalytic effect of alkali metals of fullerane formation. ► Hydrogen storage properties of alkali metal hydrides and fullerene composites. ► Novel intercalation of Na and Li in the fullerene lattice. ► Reversible phase transformation of C{sub 60} from fcc to bcc upon de/rehydrogenation. ► Potential to enable to the formation of other carbon based hydrogen storage systems. -- Abstract: In this report we describe and compare the hydrogen storage properties of lithium and sodium doped fullerenes prepared via a solvent-assisted mixing process. For the preparation of these samples either NaH or LiH was utilized as the alkali metal source to make material based on either a Na{sub 6}C{sub 60} or Li{sub 6}C{sub 60}. Both of the alkali-doped materials can reversibly absorb and desorb hydrogen at much milder conditions than the starting materials used to make them (decomposition temperatures of NaH > 420 °C, LiH > 670 °C, and fullerane > 500 °C). The hydrogen storage properties of the materials were compared by TGA, isothermal desorption, and XRD analysis. It was determined that the sodium-doped material can reversibly store 4.0 wt.% H{sub 2} while the lithium doped material can reversibly store 5.0 wt.% H{sub 2} through a chemisorption mechanism indicated by the formation and measurement of C–H bonds. XRD analysis of the material demonstrated that a reversible phase transition between fcc and bcc occurs depending on the temperature at which the hydrogenation is performed. In either system the active hydrogen storage material resembles a hydrogenated fullerene (fullerane)

Comparative study of reversible hydrogen storage in alkali-doped fulleranes

International Nuclear Information System (INIS)

Teprovich, Joseph A.; Knight, Douglas A.; Peters, Brent; Zidan, Ragaiy

2013-01-01

Highlights: ► Catalytic effect of alkali metals of fullerane formation. ► Hydrogen storage properties of alkali metal hydrides and fullerene composites. ► Novel intercalation of Na and Li in the fullerene lattice. ► Reversible phase transformation of C 60 from fcc to bcc upon de/rehydrogenation. ► Potential to enable to the formation of other carbon based hydrogen storage systems. -- Abstract: In this report we describe and compare the hydrogen storage properties of lithium and sodium doped fullerenes prepared via a solvent-assisted mixing process. For the preparation of these samples either NaH or LiH was utilized as the alkali metal source to make material based on either a Na 6 C 60 or Li 6 C 60 . Both of the alkali-doped materials can reversibly absorb and desorb hydrogen at much milder conditions than the starting materials used to make them (decomposition temperatures of NaH > 420 °C, LiH > 670 °C, and fullerane > 500 °C). The hydrogen storage properties of the materials were compared by TGA, isothermal desorption, and XRD analysis. It was determined that the sodium-doped material can reversibly store 4.0 wt.% H 2 while the lithium doped material can reversibly store 5.0 wt.% H 2 through a chemisorption mechanism indicated by the formation and measurement of C–H bonds. XRD analysis of the material demonstrated that a reversible phase transition between fcc and bcc occurs depending on the temperature at which the hydrogenation is performed. In either system the active hydrogen storage material resembles a hydrogenated fullerene (fullerane)

Alkali metal hydride formation

International Nuclear Information System (INIS)

1976-01-01

The present invention relates to a method of producing alkali metal hydrides by absorbing hydrogen gas under pressure into a mixture of lower alkyl mono amines and alkali metal alkyl amides selected from sodium and potassium amides formed from said amines. The present invention also includes purification of a mixture of the amines and amides which contain impurities, such as is used as a catalytic exchange liquid in the enrichment of deuterium, involving the formation of the alkali metal hydride

Process for the disposal of alkali metals

International Nuclear Information System (INIS)

Lewis, L.C.

1979-01-01

The invention describes a method of disposing of alkali metals by forming a solid waste for storage. The method comprises preparing an aqueous disposal solution of at least 55 weight percent alkali metal hydroxide, heating the alkali metal to melting temperature to form a feed solution, and spraying the molten feed solution into the disposal solution. The alkali metal reacts with the water in the disposal solution in a controlled reaction which produces alkali metal hydroxide, hydrogen and heat and thereby forms a solution of alkali metal hydroxides. Water is added to the solution in amounts sufficient to maintain the concentration of alkali metal hydroxides in the solution at 70 to 90 weight percent, and to maintain the temperature of the solution at about the boiling point. Removing and cooling the alkali metal hydroxide solution thereby forms a solid waste for storage. The method is particularly applicable to radioactive alkali metal reactor coolant. (auth)

Upgrading of petroleum oil feedstocks using alkali metals and hydrocarbons

Science.gov (United States)

Gordon, John Howard

2014-09-09

A method of upgrading an oil feedstock by removing heteroatoms and/or one or more heavy metals from the oil feedstock composition. This method reacts the oil feedstock with an alkali metal and an upgradant hydrocarbon. The alkali metal reacts with a portion of the heteroatoms and/or one or more heavy metals to form an inorganic phase separable from the organic oil feedstock material. The upgradant hydrocarbon bonds to the oil feedstock material and increases the number of carbon atoms in the product. This increase in the number of carbon atoms of the product increases the energy value of the resulting oil feedstock.

On-line alkali monitoring - Part 1

International Nuclear Information System (INIS)

Andersson, Christer; Ljung, P.; Woxlin, H.

1997-02-01

As a consequence of the increased knowledge of the environmental impact of combustion based heat and power generation, the use of renewable biofuels will be increased. An obstacle associated to biofuel combustion compared to other fuels is the large release of alkali. Alkali compounds in flue gases are known to cause severe operational problems. Three of the major problems are; fouling of superheating tubes (causing reduced heat transfer and possibly corrosion), agglomeration of the bed material in fluidized beds, and poisoning of SCR catalysts. Yet another alkali related problem arises when, in order to increase the electric efficiency of combustion power plants, combined-cycle technology is used. Alkali vapour present in the fuel gas for the gas turbine is condensed to particles which increase corrosion and erosion of the turbine blades. The research on ash related operational problems has to be extended in order to ensure future use of biofuels in heat and power generation. In all successful research, adequate tools are necessary. To investigate ash related problems the key issue is to be able to perform continuous alkali measurements. This pilot study has investigated the need of continuous alkali measurements, which alkali species are harmful in the different applications and also available instrumentation capable of measuring the specific alkali species. The report gives a short summary presenting alkali related operational problems. In addition a schematic overview is given, showing the alkali species that possibly can exist in various parts of the power plant. 48 refs, 13 figs, 4 tabs

Effect of nitrogen and oxygen on radiolysis of iodide solution

Energy Technology Data Exchange (ETDEWEB)

Karasawa, H; Endo, M [Hitachi Ltd., Power and Industrial System R+D Divisions, Ibaraki (Japan)

1996-12-01

The effect of nitrogen and oxygen on radiolysis of iodide solution was examined. Direct decomposition of nitrogen by {gamma}-radiation produced nitric acid to decrease a water pH. This resulted in the iodine formation in the radiolysis of iodide solution. Hydrogen peroxide was produced by the radiolysis of water containing oxygen. This worked a reducing agent to suppress the formation of iodine in the radiolysis of iodide solution. In the analytical model, fourteen iodine species were considered and reaction scheme consisted in 124 reactions. The analytical model could estimate the oxidation state of iodide ions. (author) 4 figs., 4 refs.

Effect of alkali lignins with different molecular weights from alkali pretreated rice straw hydrolyzate on enzymatic hydrolysis.

Science.gov (United States)

Li, Yun; Qi, Benkun; Luo, Jianquan; Wan, Yinhua

2016-01-01

This study investigated the effect of alkali lignins with different molecular weights on enzymatic hydrolysis of lignocellulose. Different alkali lignins fractions, which were obtained from cascade ultrafiltration, were added into the dilute acid pretreated (DAP) and alkali pretreated (AP) rice straws respectively during enzymatic hydrolysis. The results showed that the addition of alkali lignins enhanced the hydrolysis and the enhancement for hydrolysis increased with increasing molecular weights of alkali lignins, with maximum enhancement being 28.69% for DAP and 20.05% for AP, respectively. The enhancement was partly attributed to the improved cellulase activity, and filter paper activity increased by 18.03% when adding lignin with highest molecular weight. It was found that the enhancement of enzymatic hydrolysis was correlated with the adsorption affinity of cellulase on alkali lignins, and the difference in surface charge and hydrophobicity of alkali lignins were responsible for the difference in affinity between cellulase and lignins. Copyright © 2015 Elsevier Ltd. All rights reserved.

Research on solubility characteristics of gaseous methyl iodide

International Nuclear Information System (INIS)

Zhou Yanmin; Sun Zhongning; Gu Haifeng; Wang Junlong

2014-01-01

With the deionized water as the absorbent, the solubility characteristics of the gaseous methyl iodide were studied under different temperature and pressure conditions, using a dynamic measuring method. The results show that within the range of experiment parameters, namely temperature is below 80℃ and pressure is lower than 0.3 MPa, the physical dissolution process of gaseous methyl iodide in water obeys Henry's law. The solubility coefficient under different temperature and pressure conditions was calculated based on the measurement results. Further research indicates that at atmospheric pressure, the solubility coefficient of methyl iodide in water decreases exponentially with the increase of temperature. While the pressure changes from 0.1 MPa to 0.3 MPa with equal interval, the solubility coefficient also increases linearly. The variation of the solubility coefficient with temperature under different pressure conditions all decreases exponentially. An equation is given to calculate the solubility coefficient of methyl iodide under different pressure and temperature conditions. (authors)

Kinetic method for determination of iodide ion ultramicroamounts

International Nuclear Information System (INIS)

Barkauskas, Yu.K.; Ramanauskas, Eh.I.

1980-01-01

A kinetic method for iodides ultramicroamount determination from their catalytic effect on oxidation of malachite green with chloramine B in the presence of acetone at pH 5.78+-0.3 is developed. The induction period of the reaction is determined from a change in the redox potential of the system. The induction period is proportional to the iodides concentration. Determination limit of iodides is equal to 4 μg iodide per 100 l of solution. More than 10 5 -multiple amounts of K + , Na + , NH 4+ , Ba 2 + , Al 3 + , Cu 2 + , Mg 2 + , SO 4 2 - , Cl - , MoO 4 2 - , NO 3- , ClO 3- , IO 3- , IO 4- , ClO 4- , BrO 3- ; 10 5 -10 3 -multiple amounts of Cr 3 + , Fe 3 + , Sn 2 + , S 2 - , MnO 4- , NO 2- etc. do not interfere with the determination, while 10-multiple amounts of SCN, 0.2-multiple quantities of Ag + , Hg 2 2 + do

Development of processes for the production of solar grade silicon from halides and alkali metals, phase 1 and phase 2

Science.gov (United States)

Dickson, C. R.; Gould, R. K.; Felder, W.

1981-01-01

High temperature reactions of silicon halides with alkali metals for the production of solar grade silicon are described. Product separation and collection processes were evaluated, measure heat release parameters for scaling purposes and effects of reactants and/or products on materials of reactor construction were determined, and preliminary engineering and economic analysis of a scaled up process were made. The feasibility of the basic process to make and collect silicon was demonstrated. The jet impaction/separation process was demonstrated to be a purification process. The rate at which gas phase species from silicon particle precursors, the time required for silane decomposition to produce particles, and the competing rate of growth of silicon seed particles injected into a decomposing silane environment were determined. The extent of silane decomposition as a function of residence time, temperature, and pressure was measured by infrared absorption spectroscopy. A simplistic model is presented to explain the growth of silicon in a decomposing silane enviroment.

Silver iodide reduction in aqueous solution: application to iodine enhanced separation during spent nuclear fuels reprocessing

International Nuclear Information System (INIS)

Badie, Jerome

2002-01-01

Silver iodide is a key-compound in nuclear chemistry either in accidental conditions or during the reprocessing of spent nuclear fuel. In that case, the major part of iodine is released in molecular form into the gaseous phase at the time of dissolution in nitric acid. In French reprocessing plants, iodine is trapped in the dissolver off-gas treatment unit by two successive steps: the first consists in absorption by scrubbing with a caustic soda solution and in the second, residual iodine is removed from the gaseous stream before the stack by chemisorption on mineral porous traps made up of beds of amorphous silica or alumina porous balls impregnated with silver nitrate. Reactions of iodine species with the impregnant are assumed to lead to silver iodide and silver iodate. Enhanced separation policy would make necessary to recover iodine from the filters by silver iodide dissolution during a reducing treatment. After a brief silver-iodine chemical bibliographic review, the possible reagents listed in the literature were studied. The choice has been made to use ascorbic acid and hydroxylamine. An experimental work on silver iodide reduction by this two compounds allowed us to determinate reaction products, stoichiometry and kinetics parameters. Finally, the process has been initiated on stable iodine loaded filters samples. (author) [fr

Products of the reaction between methylene iodide and tertiary arsines

International Nuclear Information System (INIS)

Gigauri, R.D.; Arabuli, L.G.; Machaidze, Z.I.; Rusiya, M.Sh.

2005-01-01

Iodides of iodomethylenetrialkyl(aryl) arsonium were synthesized with high yields as a result of interaction between methylene iodide and tertiary arsines. Exchange reactions of the iodides prepared with lead(II) nitrate in water-alcohol solutions gave rise to formation of iodomethylenetrialkyl(aryl) arsonium nitrates. All the products prepared were characterized by data of elementary analysis, IR spectroscopy, conductometry and melting points measurements [ru

Alkali and heavy metal emissions of the PCFB-process; Alkali- ja raskasmetallipaeaestoet PCFB-prosessista

Energy Technology Data Exchange (ETDEWEB)

Kuivalainen, R; Eriksson, T; Lehtonen, P [Foster Wheeler Energia Oy, Karhula (Finland)

1997-10-01

Pressurized Circulating Fluidized Bed (PCFB) combustion technology has been developed in Karhula R and D Center since 1986. As part of the development, 10 MW PCFB test facility was built in 1989. The test facility has been used for performance testing with different coal types through the years 1990-1995 in order to gain data for design and commercialization of the high-efficiency low-emission PCFB combustion technology. The main object of the project was to measure vapor phase Na and K concentrations in the PCFB flue gas after hot gas filter and investigate the effects of process conditions and sorbents on alkali release. The measurements were performed using plasma assisted method of TUT Laboratory of Plasma Technology and wet absorption method of VTT Energy. The measurements were carried out during three test campaigns at PCFB Test Facility in Karhula. In autumn 1995 both VTT and TUT methods were used. The measurements of the following test period in spring 1996 were performed by VTT, and during the last test segment in autumn 1996 TUT method was in use. During the last test period, the TUT instrument was used as semi-continuous (3 values/minute) alkali analyzer for part of the time. The measured Na concentrations were below 30 ppb(w) in all measured data points. The results of K were below 10 ppb(w). The accuracies of the both methods are about +50 % at this concentration range. The scatter of the data covers the effects of different process variables on the alkali emission. The measured emissions are at the same order of magnitude as the guideline emission limits estimated by gas turbine manufacturers

On-chip fabrication of alkali-metal vapor cells utilizing an alkali-metal source tablet

International Nuclear Information System (INIS)

Tsujimoto, K; Hirai, Y; Sugano, K; Tsuchiya, T; Tabata, O; Ban, K; Mizutani, N

2013-01-01

We describe a novel on-chip microfabrication technique for the alkali-metal vapor cell of an optically pumped atomic magnetometer (OPAM), utilizing an alkali-metal source tablet (AMST). The newly proposed AMST is a millimeter-sized piece of porous alumina whose considerable surface area holds deposited alkali-metal chloride (KCl) and barium azide (BaN 6 ), source materials that effectively produce alkali-metal vapor at less than 400 °C. Our experiments indicated that the most effective pore size of the AMST is between 60 and 170 µm. The thickness of an insulating glass spacer holding the AMST was designed to confine generated alkali metal to the interior of the vapor cell during its production, and an integrated silicon heater was designed to seal the device using a glass frit, melted at an optimum temperature range of 460–490 °C that was determined by finite element method thermal simulation. The proposed design and AMST were used to successfully fabricate a K cell that was then operated as an OPAM with a measured sensitivity of 50 pT. These results demonstrate that the proposed concept for on-chip microfabrication of alkali-metal vapor cells may lead to effective replacement of conventional glassworking approaches. (paper)

Porous alkali activated materials with slow alkali release dynamic. Role of composition

International Nuclear Information System (INIS)

Bumanis, G.; Bajare, D.

2018-01-01

Alkali activated materials (AAM) based on calcined metakaolin or illite clay together with waste by-products, such as waste glass or aluminium scrap recycling waste, were tested as value-added materials for pH stabilization in biogas technology where decrease of pH should be avoided. Porous materials with ability to slowly leach alkalis in the water media thus providing continuous control of the pH level were obtained. XRD, FTIR, SEM and titration methods were used to characterize AAM and their leaching properties. It is clear that composition of the material has an important effect on the diffusion of alkali from structure. Namely, higher Si/Al and Na/Al molar ratios may increase pore solution transfer to the leachate. The leaching rate of alkalis from the structure of AAM is high for the first few days, decreasing over time. It was possible to calculate the buffer capacity from the mixture design of AAM. [es

Permeation of iodide from iodine-enriched yeast through porcine intestine.

Science.gov (United States)

Ryszka, Florian; Dolińska, Barbara; Zieliński, Michał; Chyra, Dagmara; Dobrzański, Zbigniew

2013-01-01

Iodine deficiency is a common phenomenon, threatening the whole global human population. Recommended daily intake of iodine is 150 μg for adults and 250 μg for pregnant and breastfeeding women. About 50% of human population can be at risk of moderate iodine deficiency. Due to this fact, increased iodine supplementation is recommended, through intake of iodized mineral water and salt iodization. The aim of this study was to investigate permeation and absorption of iodide from iodine bioplex (experimental group) in comparison with potassium iodide (controls). Permeation and absorption processes were investigated in vitro using a porcine intestine. The experimental model was based on a standard Franz diffusion cell (FD-Cell). The iodine bioplex was produced using Saccharomyces cerevisiae yeast and whey powder: iodine content - 388 μg/g, total protein - 28.5%, total fat - 0.9%., glutamic acid - 41.2%, asparaginic acid - 29.4%, lysine - 24.8%; purchased from: F.Z.N.P. Biochefa, Sosnowiec, Poland. Potassium iodide was used as controls, at 388 μg iodine concentration, which was the same as in iodine-enriched yeast bioplex. A statistically significant increase in iodide permeation was observed for iodine-enriched yeast bioplex in comparison with controls - potassium iodide. After 5h the total amount of permeated iodide from iodine-enriched yeast bioplex was 85%, which is ~ 2-fold higher than controls - 37%. Iodide absorption was by contrast statistically significantly higher in controls - 7.3%, in comparison with 4.5% in experimental group with iodine-enriched yeast bioplex. Presented results show that iodide permeation process dominates over absorption in case of iodine-enriched yeast bioplex.

Purification of alkali metal nitrates

Science.gov (United States)

Fiorucci, Louis C.; Gregory, Kevin M.

1985-05-14

A process is disclosed for removing heavy metal contaminants from impure alkali metal nitrates containing them. The process comprises mixing the impure nitrates with sufficient water to form a concentrated aqueous solution of the impure nitrates, adjusting the pH of the resulting solution to within the range of between about 2 and about 7, adding sufficient reducing agent to react with heavy metal contaminants within said solution, adjusting the pH of the solution containing reducing agent to effect precipitation of heavy metal impurities and separating the solid impurities from the resulting purified aqueous solution of alkali metal nitrates. The resulting purified solution of alkali metal nitrates may be heated to evaporate water therefrom to produce purified molten alkali metal nitrate suitable for use as a heat transfer medium. If desired, the purified molten form may be granulated and cooled to form discrete solid particles of alkali metal nitrates.

The chemistry of the liquid alkali metals

International Nuclear Information System (INIS)

Addison, C.C.

1984-01-01

A study of liquid alkali metals. It encourages comparison with molecular solvents in chapter covering the nature and reactivity of dissolved species, solvation, solubility and electrical conductivity of solutions. It demonstrates lab techniques unique to liquid alkali metals. It discusses large-scale applications from storage batteries to sodium-cooled reactors and future fusion reactors, and associated technological problems. Contents: Some Basic Physical and Chemical Properties; Manipulation of the Liquids; The Chemistry of Purification Methods; Species Formed by Dissolved Elements; Solubilities and Analytical Methods; Alkali Metal Mixtures; Solvation in Liquid Metal; Reactions Between Liquid Alkali Metals and Water; Reactions of Nitrogen with Lithium and the Group II Metals in Liquid Sodium; The Formation, Dissociation and Stability of Heteronuclear Polyatomic Anions; Reactions of the Liquid Alkali Metals and Their Alloys with Simple Alipatic Hydrocarbons; Reactions of the Liquid Alkali Metals with Some Halogen Compounds; Hydrogen, Oxygen and Carbon Meters; Surface Chemistry and Wetting; Corrosion of Transition Metals by the Liquid Alkali Metals; Modern Applications of the Liquid Alkali Metals

Alkali and heavy metals emissions of the PCFB-process

International Nuclear Information System (INIS)

Kuivalainen, R.; Eriksson, T.; Koskinen, J.; Lehtonen, P.

1995-01-01

Pressurized Circulating Fluidized Bed (PCFB) combustion technology has been developed by A. Ahlstrom Corporation since 1986. As a part of the development, a 10 MV PCFB Test Facility was constructed at Hans Ahlstrom Laboratory in Karhula, Finland in 1989. The Test Facility has been used for performance testing with different coal types through the years 1990-1994 for obtaining data for design and commercialization of the high-efficiency low-emission PCFB combustion technology. The project Y44 'Alkali and heavy metal emissions of the PCFB-process' is part of national LIEKKI 2 research program and it continues the work started under alkali measurement project Y33 in 1994. The objective of the project is to measure vapor phase alkali and heavy metal concentrations in the PCFB flue gas after high-temperature high-pressure particulate filter and to investigate the effects of process conditions and sorbents on alkali release. The measured Na concentrations were between 0,03 and 0,21 ppm(w). The results of K were between 0,01 and 0,08 ppm(w). The accuracy of the results is about +-50 percent at this concentration range. The scatter of the data covers the effects of different process variables on the alkali emission. The measured emissions at 800-850 deg C are at the same order of magnitude as the guideline emission limits given by gas turbine manufacturers for flue gas at 1000-1200 deg C. The measurements and development of the analyses methods are planned to be continued during PCFB test runs in autumn 1995 in cooperation with laboratories of VTT Energy and Tampere University of Technology. (author)

Laccase-catalyzed oxidation of iodide and formation of organically bound iodine in soils.

Science.gov (United States)

Seki, Miharu; Oikawa, Jun-ichi; Taguchi, Taro; Ohnuki, Toshihiko; Muramatsu, Yasuyuki; Sakamoto, Kazunori; Amachi, Seigo

2013-01-02

Laccase oxidizes iodide to molecular iodine or hypoiodous acid, both of which are easily incorporated into natural soil organic matter. In this study, iodide sorption and laccase activity in 2 types of Japanese soil were determined under various experimental conditions to evaluate possible involvement of this enzyme in the sorption of iodide. Batch sorption experiment using radioactive iodide tracer ((125)I(-)) revealed that the sorption was significantly inhibited by autoclaving (121 °C, 40 min), heat treatment (80 and 100 °C, 10 min), γ-irradiation (30 kGy), N(2) gas flushing, and addition of reducing agents and general laccase inhibitors (KCN and NaN(3)). Interestingly, very similar tendency of inhibition was observed in soil laccase activity, which was determined using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) as a substrate. The partition coefficient (K(d): mL g(-1)) for iodide and specific activity of laccase in soils (Unit g(-1)) showed significant positive correlation in both soil samples. Addition of a bacterial laccase with an iodide-oxidizing activity to the soils strongly enhanced the sorption of iodide. Furthermore, the enzyme addition partially restored iodide sorption capacity of the autoclaved soil samples. These results suggest that microbial laccase is involved in iodide sorption on soils through the oxidation of iodide.

Colorimetric sensing of iodide based on triazole-acetamide functionalized gold nanoparticles

International Nuclear Information System (INIS)

Lee, I-Lin; Sung, Yi-Ming; Wu, Shu-Pao; Wu, Chien-Hou

2014-01-01

We have modified gold nanoparticles (AuNPs) with triazole acetamide to obtain a material for the sensitive and selective colorimetric determination of iodide. The functionalized AuNPs were prepared by a reductive single chemical step using a Cu(I)-catalyzed click reaction. The presence of iodide ions induces the aggregation of these AuNPs and results in a color change from wine-red to purple. The iodide-induced aggregation can be detected visually with bare eyes, but also by photometry. The detection limit is as low as 15 nM. The method displays excellent selectivity for iodide over other anions due to the selective interaction with the amido groups of the triazole. The method was applied to the determination of iodide in spiked lake waters. (author)

The self-trapping of anion excitons in alkali halides at elastic deformation

International Nuclear Information System (INIS)

Tulepbergenov, S.K.; Dzhumanov, S.; Spivak-Lavrov, I.F.; Shunkeev, K.Sh.

2001-01-01

The self-trapping of electronic excitations (EE) (excitons, holes and electrons) in alkali halides (AH), fluorides and oxides plays an important roles in luminescence and defect formation. Therein the specific features of self-trapping of EE in various materials are essentially different. In particular, the self-trapping of excitons in some AH (i.e. alkali iodides and bromides) occurs with overcoming of the potential barrier and in other AH (e.g. alkali fluorides and chlorides) such a barrier is absent. Here we develop the continuum theory of self-trapping of within the adiabatic approximation elastically stressed AH. In the continuum model of solids the functional of the total energy of are interacting exciton-phonon system in the deformed ionic crystal just as in the undeformed crystal depends on the dilation Δ(r) described by the deformation potential of acoustic phonon, the electrostatic potential φ[r) due to the lattice polarization at optical lattice vibrations and the wave function of exciton chosen for hydro statically and uniaxially stressed 3D crystals. The functionals of the total energy of the interfacing exciton-phonon system E{Δ(r),φ(r),ψ(r)} are minimized relative to Δ, φ and ψ for the cases of isotropic and anisotropic 3D crystals. As a result, we obtained the functionals depending on μ and determined their possible extremum. We have show that the linear deformations under the hydrostatic and uniaxial stress at 80 K lead to the decreasing of the self trapping barrier for exciton and to the increasing of the luminescence of self-trapped excitons (STE). While the nonlinear deformations under the such stress at 80 K lead to the increasing of the self-trapping barrier for excitons and to the decreasing at the STE luminescence in AH. At T=0 K the small hydrostatic and uniaxial pressures lead to the same effects. Further at hydrostatic and uniaxial compressions of AH the minimums of the adiabatic potentials of quasifree and STE are shifted to

Effect of alkali and heat treatments for bioactivity of TiO{sub 2} nanotubes

Energy Technology Data Exchange (ETDEWEB)

Kim, Seo young, E-mail: mast6269@nate.com [Dept. of Dental Biomaterials and Institute of Bio degradable material, Institute of Oral Bioscience and BK21 plus project, School of Dentistry, Chonbuk National University, Jeonju, 561-756 (Korea, Republic of); Kim, Yu kyoung, E-mail: yk0830@naver.com [Dept. of Dental Biomaterials and Institute of Bio degradable material, Institute of Oral Bioscience and BK21 plus project, School of Dentistry, Chonbuk National University, Jeonju, 561-756 (Korea, Republic of); Park, Il song, E-mail: ilsong@jbnu.ac.kr [Division of Advanced Materials Engineering, Research Center for Advanced Materials Development and Institute of Biodegradable Materials, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Jin, Guang chun, E-mail: jingc88@126.com [Oral Medical College, Beihua University, Jilin City 132013 (China); Bae, Tae sung, E-mail: bts@jbnu.ac.kr [Dept. of Dental Biomaterials and Institute of Bio degradable material, Institute of Oral Bioscience and BK21 plus project, School of Dentistry, Chonbuk National University, Jeonju, 561-756 (Korea, Republic of); Lee, Min ho, E-mail: mh@jbnu.ac.kr [Dept. of Dental Biomaterials and Institute of Bio degradable material, Institute of Oral Bioscience and BK21 plus project, School of Dentistry, Chonbuk National University, Jeonju, 561-756 (Korea, Republic of)

2014-12-01

Highlights: • TiO{sub 2} nanotubes formed via anodization were treated by alkali and heat. • The surface roughness was increased after alkali treatment (p < 0.05). • After alkali and heat treatment, the wettability was better than before treatment. • Alkali treated TiO{sub 2} nanotubes were shown higher HAp formation in SBF. • Heat treatment affected on the attachment of cells for alkali treated nanotubes. - Abstract: In this study, for improving the bioactivity of titanium used as an implant material, alkali and heat treatments were carried out after formation of the nanotubes via anodization. Nanotubes with uniform length, diameter, and thickness were formed by anodization. The alkali and heat-treated TiO{sub 2} nanotubes were covered with the complex network structure, and the Na compound was generated on the surface of the specimens. In addition, after 5 and 10 days of immersion in the SBF, the crystallized OCP and HAp phase was significantly increased on the surface of the alkali-treated TiO{sub 2} nanotubes (PNA) and alkali and heat-treated TiO{sub 2} nanotubes (PNAH) groups. Cell proliferation was decreased due to the formation of amorphous sodium titanate (Na{sub 2}TiO{sub 3}) layer on the surface of the PNA group. However, anatase and crystalline sodium titanate were formed on the surface of the PNAH group after heat treatment at 550 °C, and cell proliferation was improved. Thus, PNA group had higher HAp forming ability in the simulated body fluid. Additional heat treatment affected on enhancement of the bioactivity and the attachment of osteoblasts for PNA group.

Mechanisms and kinetics of electrodeposition of alkali metals on solid and liquid mercury electrodes

Energy Technology Data Exchange (ETDEWEB)

Lu, Wenzhe.

1993-01-01

Electroreduction of alkali metal ions at mercury is an important area in electrochemistry related to the battery industry. In this work, four major topics were considered: alkali metal/mercury interactions; electrosorption of alkali metal ions on solid mercury; electroreduction of alkali metal/crown ether complexes; and ammonium amalgam formation. The formation of alkali metal-mercury intermetallic compounds was studied on liquid and frozen thin layer mercury electrodes. The stoichiometry of the compounds produced under these conditions was determined using cyclic voltammetry. As expected, formation of a new phase was preceded by nucleation phenomena, which were particularly easy to monitor at solid Hg electrodes. The nucleation kinetics were studied using the chronoamperometric method. At very low temperatures, when the mobility of mercury atoms was restricted, the electrosorption of alkali metal ions on solid mercury electrodes was noted. Subsequent study allowed determination of the electrosorption parameters. The free energy of electrosorption is discussed in terms of interactions between alkali metals and mercury. The effect of crown ethers on the kinetics of alkali metal ion reduction was studied at both standard size and ultramicro-mercury electrodes in nonaqueous solutions using ultrafast cyclic voltammetry and ac voltammetry. The usefulness of ultrafast cyclic voltammetry with ultramicroelectrodes in measurements of the kinetics of amalgam formation was verified in a brief study of cadmium ion reduction. The mechanism of the complex reduction at mercury was analyzed based on the free energy changes before and after the activation state. In addition, the stoichiometry and formation constants of the crown ether/alkali metal complexes were determined using cyclic voltammetry. The mechanism of electroreduction of ammonium ions at mercury electrodes in non-aqueous media was analyzed.

Development of w/o microemulsion for transdermal delivery of iodide ions.

Science.gov (United States)

Lou, Hao; Qiu, Ni; Crill, Catherine; Helms, Richard; Almoazen, Hassan

2013-03-01

The objective of this study was to develop a water-in-oil (w/o) microemulsion which can be utilized as a transdermal delivery for iodide ions. Several w/o microemulsion formulations were prepared utilizing Span 20, ethanol, Capryol 90®, and water. The selected formulations had 5%, 10%, 15%, 20%, and a maximum of 23% w/w water content. Potassium iodide (KI) was incorporated in all formulations at 5% w/v. Physicochemical characterizations were conducted to evaluate the structure and stability. These studies included: mean droplet size, pH, viscosity, conductivity, and chemical stability tests. In vitro human skin permeation studies were conducted to evaluate the diffusion of the iodide ion through human skin. The w/o microemulsion formulations were stable and compatible with iodide ions with water content ranging from 5% to 23% w/w. The addition of KI influenced the physicochemical properties of microemulsion as compared to blank microemulsion formulations. In vitro human skin permeation studies indicated that selected formulations improved iodide ion diffusion significantly as compared to control (KI solution; P valuemicroemulsion. Span 20, ethanol and Capryol 90 protected the iodide ions against oxidation and formed a stable microemulsion. It is worth to note that according to Hofmeister series, iodide ions tend to lower the interfacial tension between water and oil and consequently enhance overall stability. This work illustrates that microemulsion system can be utilized as a vehicle for the transdermal administration of iodide.

Alkali metal hafnium oxide scintillators

Science.gov (United States)

Bourret-Courchesne, Edith; Derenzo, Stephen E.; Taylor, Scott Edward

2018-05-08

The present invention provides for a composition comprising an inorganic scintillator comprising an alkali metal hafnate, optionally cerium-doped, having the formula A2HfO3:Ce; wherein A is an alkali metal having a valence of 1, such as Li or Na; and the molar percent of cerium is 0% to 100%. The alkali metal hafnate are scintillators and produce a bright luminescence upon irradiation by a suitable radiation.

Chemical effects of alkali atoms on critical temperature in superconducting alkali-doped fullerides

Science.gov (United States)

Hetfleisch, F.; Gunnarsson, O.; Srama, R.; Han, J. E.; Stepper, M.; Roeser, H.-P.; Bohr, A.; Lopez, J. S.; Mashmool, M.; Roth, S.

2018-03-01

Alkali metal doped fullerides (A3C60) are superconductors with critical temperatures, Tc, extending up to 38 K. Tc is known to depend strongly on the lattice parameter a, which can be adjusted by physical or chemical pressure. In the latter case an alkali atom is replaced by a different sized one, which changes a. We have collected an extensive data base of experimental data for Tc from very early up to recent measurements. We disentangle alkali atom chemical effects on Tc, beyond the well-known consequences of changing a. It is found that Tc, for a fixed a, is typically increased as smaller alkali atoms are replaced by larger ones, except for very large a. Possible reasons for these results are discussed. Although smaller in size than the lattice parameter contribution, the chemical effect is not negligible and should be considered in future physical model developments.

Ultraviolet optical absorption of alkali cyanides and alkali halide cyanides

International Nuclear Information System (INIS)

Souza Camargo Junior, S.A. de.

1982-09-01

The ultraviolet absorption spectra of alkali cyanide and mixed alkali halide cyanide crystals were measured at temperatures ranging from 300K down to 4.2K. A set of small absorption peaks was observed at energies near 6 eV and assigned to parity forbidden X 1 Σ + →a' 3 Σ + transitions of the CN - molecular ions. It was observed that the peak position depends on the alkali atom while the absorption cross section strongly depends on the halogen and on the CN - concentration of the mixed crystals. These effects are explained in terms of an interaction between the triplet molecular excitons and charge transfer excitons. The experimental data were fit with a coupling energy of a few meV. The coupling mechanism is discussed and it is found to be due to the overlap between the wave functions of the two excitations. (Author) [pt

Quantification of chlorine and alkali emissions from fluid bed combustion of coal by equilibrium calculations

Energy Technology Data Exchange (ETDEWEB)

Furimsky, Edward [IMAF Group, 184 Marlborough Avenue, Ottawa, ON (Canada) K1N 8G4; Zheng, Ligang [Natural Resources Canada, CANMET Energy Technology Centre, 1 Haanel Drive, Nepean, ON (Canada) K1A 1M1

2003-04-15

A computer model based on the Gibbs energy minimization principle was used to identify and quantify chlorine (Cl)- and alkali-containing species formed in the temperature range from 1100 to 1200 K, air/coal ratio of 1.0 and 1.1 and Ca/S ratio varying from 0 to 2.5 using low and high Cl content coals. HCl, KCl and NaCl were the major Cl-containing volatile compounds. The amount of HCl in the vapor phase decreased and that of KCl and NaCl increased with increasing Ca/S ratio from 0 to 2.5, whereas the increase in the air/coal ratio from 1.0 to 1.1 had the opposite effect. KCl and NaCl were the major, and KOH, NaOH, K{sub 2}SO{sub 4} and Na{sub 2}SO{sub 4} the minor alkali-containing species in the vapor phase of all the cases analyzed. The amount of all alkali metal-containing compounds increased with increasing Ca/S ratio and decreased with increasing air/coal ratio from 1.0 to 1.1. For the low Cl coal, the relative contribution of KOH and NaOH to the overall alkali emissions was greater than that for the high Cl coal.

Corrosion inhibition

Energy Technology Data Exchange (ETDEWEB)

Fisher, A O

1965-12-29

An acid corrosion-inhibiting composition consists essentially of a sugar, and an alkali metal salt selected from the group consisting of iodides and bromides. The weight ratio of the sugar to the alkali metal salt is between 2:1 and about 20,000:1. Also, a corrosion- inhibited phosphoric acid composition comprising at least about 20 wt% of phosphoric acid and between about 0.1 wt% and about 10 wt% of molasses, and between about 0.0005 wt% and about 1 wt% of potassium iodide. The weight ratio of molasses to iodide is greater than about 2:1. (11 claims)

Pyrolysis characteristic of kenaf studied with separated tissues, alkali pulp, and alkali li

Directory of Open Access Journals (Sweden)

Yasuo Kojima

2015-12-01

Full Text Available To estimate the potential of kenaf as a new biomass source, analytical pyrolysis was performed using various kenaf tissues, i.e., alkali lignin and alkali pulp. The distribution of the pyrolysis products from the whole kenaf was similar to that obtained from hardwood, with syringol, 4-vinylsyringol, guaiacol, and 4-vinylguaiacol as the major products. The phenols content in the pyrolysate from the kenaf core was higher than that from the kenaf cuticle, reflecting the higher lignin content of the kenaf core. The ratios of the syringyl and guaiacyl compounds in the pyrolysates from the core and cuticle samples were 2.79 and 6.83, respectively. Levoglucosan was the major pyrolysis product obtained from the kenaf alkali pulp, although glycol aldehyde and acetol were also produced in high yields, as previously observed for other cellulosic materials. Moreover, the pathways for the formation of the major pyrolysis products from alkali lignin and alkali pulp were also described, and new pyrolysis pathways for carbohydrates have been proposed herein. The end groups of carbohydrates bearing hemiacetal groups were subjected to ring opening and then they underwent further reactions, including further thermal degradation or ring reclosing. Variation of the ring-closing position resulted in the production of different compounds, such as furans, furanones, and cyclopentenones.

Well-ordered monolayers of alkali-doped coronene and picene: Molecular arrangements and electronic structures

Energy Technology Data Exchange (ETDEWEB)

Yano, M.; Endo, M.; Hasegawa, Y.; Okada, R.; Yamada, Y., E-mail: yamada@bk.tsukuba.ac.jp; Sasaki, M. [Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan)

2014-07-21

Adsorptions of alkali metals (such as K and Li) on monolayers of coronene and picene realize the formation of ordered phases, which serve as well-defined model systems for metal-intercalated aromatic superconductors. Upon alkali-doping of the monolayers of coronene and picene, scanning tunneling microscopy and X-ray absorption spectroscopy revealed the rearrangement of the entire molecular layer. The K-induced reconstruction of both monolayers resulted in the formation of a structure with a herringbone-like arrangement of molecules, suggesting the intercalation of alkali metals between molecular planes. Upon reconstruction, a shift in both the vacuum level and core levels of coronene was observed as a result of a charge transfer from alkali metals to coronene. In addition, a new density of states near the Fermi level was formed in both the doped coronene and the doped picene monolayers. This characteristic electronic feature of the ordered monolayer has been also reported in the multilayer picene films, ensuring that the present monolayer can model the properties of the metal-intercalated aromatic hydrocarbons. It is suggested that the electronic structure near the Fermi level is sensitive to the molecular arrangement, and that both the strict control and determinations of the molecular structure in the doped phase should be important for the determination of the electronic structure of these materials.

Alkali-ions diffusion, mullite formation, and crystals dissolution during sintering of porcelain bodies: Microstructural approach

DEFF Research Database (Denmark)

Leonelli, C.; Kamseu, E.; Boccaccini, Dino

2009-01-01

The effect of alkali-silicate glassy matrix as replacement for feldspar in soft and hard porcelain compositions was studied. SEM and X-ray diffraction analysis were used to evidence phase evolution. For each composition, the influence of soaking time was evaluated. The difference in chemical...... to hard porcelain. Replacing the feldspar by alkali-silicate glassy matrices with similar chemical composition, the amount of secondary mullite and mechanical properties increased in both soft and hard compositions....

Structure peculiarities of mixed alkali silicate glasses

International Nuclear Information System (INIS)

Bershtein, V.A.; Gorbachev, V.V.; Egorov, V.

1980-01-01

The thermal porperties and structure of alkali and mixed alkali (Li, Na, K) silicate glasses by means of differential scanning calorimetry (DSC), the positron annihilation method, X-ray fluorescence and infrared (300-30 cm -1 ) spectroscopy were studied. Introduction of different alkali cations in glass results in nonadditive change in their electron structure (bond covalence degree growth) and the thermal behaviour. The different manifestations of mixed alkali effect can be explained by the lessening of long distance Coulomb interactions and strengthening the short-range forces in the mixed alkali glasses. (orig.)

Density of mixed alkali borate glasses: A structural analysis

International Nuclear Information System (INIS)

Doweidar, H.; El-Damrawi, G.M.; Moustafa, Y.M.; Ramadan, R.M.

2005-01-01

Density of mixed alkali borate glasses has been correlated with the glass structure. It is assumed that in such glasses each alkali oxide associates with a proportional quantity of B 2 O 3 . The number of BO 3 and BO 4 units related to each type of alkali oxide depends on the total concentration of alkali oxide. It is concluded that in mixed alkali borate glasses the volumes of structural units related to an alkali ion are the same as in the corresponding binary alkali borate glass. This reveals that each type of alkali oxide forms its own borate matrix and behaves as if not affected with the presence of the other alkali oxide. Similar conclusions are valid for borate glasses with three types of alkali oxide

New insight into atmospheric alteration of alkali-lime silicate glasses

International Nuclear Information System (INIS)

Alloteau, Fanny; Lehuédé, Patrice; Majérus, Odile; Biron, Isabelle; Dervanian, Anaïs; Charpentier, Thibault; Caurant, Daniel

2017-01-01

Highlights: •Glass silicate network hydrolysis is by far the predominant reaction at 80 °C. •Atmospheric conditions yield different altered layer structure than in immersion. •The altered layer bears about 10 wt% of water mainly as H-bonded SiOH groups. •Alkali ions stay embedded into the altered layer closed to SiOH and H 2 O species. -- Abstract: A mixed alkali lime silicate glass altered in atmospheric conditions (80 °C/85%RH, Relative Humidity) for various lengths of time was characterized at all scales. The altered glass forms a hydrated solid phase bearing about 10 wt% of H 2 O in the form of Si-OH groups and molecular water. No alkali depletion was observed after ageing tests. Structural results from 1 H, 23 Na and 29 Si MAS NMR point out the close proximity of Si-OH, H 2 O and Na + species. This study gives new insight into the mechanisms of the atmospheric alteration, essential to conservation strategies in industry and cultural heritage.

Effect of alkali treatment on surface morphology of titanium

Energy Technology Data Exchange (ETDEWEB)

Tan, K. J., E-mail: gd130056@siswa.uthm.edu.my; Wahab, M. A. A., E-mail: cd110006@siswa.uthm.edu.my; Mahmod, S., E-mail: cd110201@siswa.uthm.edu.my; Idris, M. I., E-mail: izwana@uthm.edu.my; Abdullah, H. Z., E-mail: hasan@uthm.edu.my [Faculty of Mechanical and Manufacturing Engineering, Universiti Tun Hussein Onn Malaysia, 86400 Parit Raja, Batu Pahat, Johor (Malaysia)

2015-07-22

Alkali and heat treatments were first introduced by Kim et al. to prepare a bioactive surface on titanium. This method has been proven very effective and widely used in other studies to promote titanium osteointegration. This study aims to investigate further the effect of alkali treatment on surface morphology of high purity titanium. High purity titanium foils were immersed in NaOH aqueous solutions of 0.5 M, 5 M and 15 M at 60°C and 80 °C for 1, 3 and 7 days. The surface morphology was examined using Field Emission Scanning Electron Microscope (FESEM). The obtained phases were analysed using Fourier Transform Infrared Spectroscopy (FTIR) in the spectra range of 4000-600 cm{sup −1} at 4 cm{sup −1} resolution and 50 scans. At the same soaking temperature and soaking time, a thicker porous network was observed with increasing concentration of NaOH. At the same soaking temperature, a much porous structure was observed with increasing soaking time. At constant alkali concentration, more homogenously distributed porous surface structure was observed with increasing soaking temperature.

Synergistic capture mechanisms for alkali and sulfur species from combustion. Final report

Energy Technology Data Exchange (ETDEWEB)

Peterson, T.W.; Shadman, F.; Wendt, J.O.L.; Mwabe, P.O.

1994-02-01

Experimental work was carried out on a 17 kW, 600 cm long, gas laboratory combustor, to investigate the post flame reactive capture of alkali species by kaolinite. Emphasis was on alkali/sorbent interactions occurring in flue gas at temperatures above the alkali dewpoint and on the formation of water insoluble reaction products. Time-temperature studies were carried out by injecting kaolinite at different axial points along the combustor. The effect of chlorine and sulfur on alkali capture was investigated by doping the flame with SO{sub 2} and Cl{sub 2} gases to simulate coal flame environments. Particle time and temperature history was kept as close as possible to that which would ordinarily be found in a practical boiler. Experiments designed to extract apparent initial reaction rates were carried using a narrow range, 1-2 {mu}m modal size sorbent, while, a coarse, multi size sorbent was used to investigate the governing transport mechanisms. The capture reaction has been proposed to be between alkali hydroxide and activated kaolinite, and remains so in the presence of sulfur and chlorine. The presence of sulfur reduces sodium capture by under 10% at 1300{degree}C. Larger reductions at lower temperatures are attributed to the elevated dewpoint of sodium ({approximately}850{degree}C) with subsequent reduction in sorbent residence time in the alkali gas phase domain. Chlorine reduces sodium capture by 30% across the temperature range covered by the present experiments. This result has been linked to thermodynamic equilibria between sodium hydroxide, sodium chloride and water.

Thyroid iodide compartments and their implication in the rat thyroid iodine organification

International Nuclear Information System (INIS)

Bastiani, P.; Simon, C.

1982-01-01

To estimate the relative participation of transported and intrathyroidally generated iodide (internal iodide) in the iodination of newly synthesized and preexisting thyroglobulin (Tg) in the rat thyroid, the specific radioactivities (SRAs) of thyroid iodide, Tg, lysosomal iodine, and plasma hormones were followed for 92 h after radioactive iodide injection in intact or hypophysectomized rats. In control rats, the SRA of Tg and lysosomal iodine reached a maximum at 12 h. However, the SRA of lysosomal iodide was always smaller than that of Tg. In contrast, the SRA of hormonal iodide attained a maximum at 48 h. Thus, newly labeled iodine is endocytosed and mixed inside the lysosomes with older previously iodinated molecules; hormone secretion is mainly due to old labeled iodine (i.e. iodine with a high SRA from 48-96 h). These results are consistent with the presence of least two Tg compartments, with different turnover rates and hormone contents. On the other hand, in hypophysectomized rats, the SRA of Tg, lysosomes, and hormones showed only one maximum, at 24 h. Furthermore, the SRAs of Tg and lysosomes were similar at each time interval. It is inferred that in such rats, the old labeled iodine compartment is strongly reduced, and that inside the lysosomes, newly labeled iodine is predominant. Since in hypophysectomized rats, the recycling of iodide is abolished, it is concluded that in normal rats: 1) transported iodide is organified mainly by direct iodination of newly synthesized Tg, independently of TSH, and 2) internal iodide is organified mainly by delayed iodination of preexisting Tg, this process being TSH dependent

Study on gold concentrate leaching by iodine-iodide

Science.gov (United States)

Wang, Hai-xia; Sun, Chun-bao; Li, Shao-ying; Fu, Ping-feng; Song, Yu-guo; Li, Liang; Xie, Wen-qing

2013-04-01

Gold extraction by iodine-iodide solution is an effective and environment-friendly method. In this study, the method using iodine-iodide for gold leaching is proved feasible through thermodynamic calculation. At the same time, experiments on flotation gold concentrates were carried out and encouraging results were obtained. Through optimizing the technological conditions, the attained high gold leaching rate is more than 85%. The optimum process conditions at 25°C are shown as follows: the initial iodine concentration is 1.0%, the iodine-to-iodide mole ratio is 1:8, the solution pH value is 7, the liquid-to-solid mass ratio is 4:1, the leaching time is 4 h, the stirring intensity is 200 r/mim, and the hydrogen peroxide consumption is 1%.

Standard free energy of formation of iron iodide

Science.gov (United States)

Khandkar, A.; Tare, V. B.; Wagner, J. B., Jr.

1983-01-01

An experiment is reported where silver iodide is used to determine the standard free energy of formation of iron iodide. By using silver iodide as a solid electrolyte, a galvanic cell, Ag/AgI/Fe-FeI2, is formulated. The standard free energy of formation of AgI is known, and hence it is possible to estimate the standard free energy of formation of FeI2 by measuring the open-circuit emf of the above cell as a function of temperature. The free standard energy of formation of FeI2 determined by this method is -38784 + 24.165T cal/mol. It is estimated that the maximum error associated with this method is plus or minus 2500 cal/mol.

Alkali emissions of the PCFB-process

International Nuclear Information System (INIS)

Kuivalainen, R.; Eriksson, T.; Koskinen, J.; Lehtonen, P.

1995-01-01

Pressurized Circulating Fluidized Bed (PCFB) combustion technology has been developed by A. Ahlstrom Corporation since 1986. As a part of the development, a 10 MW PCFB Test Facility was constructed at Hans Ahlstrom Laboratory in Karhula, Finland in 1989. The Test Facility has been used for performance testing with different coal types through the years 1990-1994 in order to gain data for design and commercialization of the high-efficiency low- emission PCFB combustion technology. The project Y33 'Alkali emissions of the PCFB-process' was part of national LIEKKI 2 research program. The object of the project was to measure vapor phase Na and K concentrations in the PCFB flue gas after hot gas filter and investigate the effects of process conditions and sorbents on alkali release. The measured Na concentrations were between 0,03 and 0,21 ppm(w). The results of K were between 0,01 and 0,08 ppm(w). The accuracy of the results is about +-50 percent at this concentration range. The scatter of the data covers the effects of different process variables on the alkali emission . The measured emissions at 800-850 deg C are at the same order of magnitude as the guideline emission limits given by gas turbine manufacturers for flue gas at 1000-1200 deg C. The measurements and development of the analyses methods are planned to be continued during PcFB test runs in autumn 1995 in cooperation with laboratories of VTT Energy and Tampere University of Technology. (author)

Direct observation of the release of alkali vapor species in biofuel combustion and gasification

Energy Technology Data Exchange (ETDEWEB)

French, R.J.; Milne, T.A. [National Renewable Energy Lab., Golden, CO (United States)

1993-12-31

The largest present use of biomass for energy is in combustion for steam and electrical power. Biofuels have an acknowledged advantage over coal as a solid fuel because of their low sulfur and ash content. However, some forms of biomass have substantial quantities of alkali metals and chlorine. In addition, evidence indicates that the alkali in biomass is largely atomically dispersed, resulting in its facile mobilization into the gas-phase. Gaseous alkali compounds aggravate problems of slagging, fouling, and corrosion on heat transfer surfaces in present-day boilers. These problems can be particularly severe when mixed and variable agricultural residues are burned. Furthermore, the next generation of biomass-to-power systems will likely involve combined cycle gas turbines, where alkali tolerances are especially restrictive. In this paper, we report on laboratory studies in which biofuels are combusted under simulated turbine or boiler-firing conditions. Gaseous alkali, sulfur, nitrogen, and halogen-containing species are measured by direct extraction from the hot gases through molecular-beam mass spectrometry (MBMS). The experimental apparatus will be described and its capability illustrated with results of time-resolved evolution of species like K, KCl, KOH, SO{sub 2} and NO{sub x} from small samples of biomass in combustion environments. The nature and release of such species will be explicated by referring to thermodynamic equilibrium predictions and the form of alkali in solid, gaseous, and liquid biofuels.

Behavior of radioactive organic iodide in an atmosphere of High Temperature Gas-cooled Reactor

International Nuclear Information System (INIS)

Saeki, Masakatsu; Nakashima, Mikio; Sagawa, Chiaki; Masaki, Nobuyuki; Hirabayashi, Takakuni; Aratono, Yasuyuki

1990-06-01

Formation and decomposition behavior of radioactive organic iodide have been studied in an atmosphere of High Temperature Gas-cooled Reactor (High Temperature Engineering Test Reactor, HTTR). Na 125 I was chosen for radioactive iodine source instead of CsI diffusing from coated fuel particles. Na 125 I adsorbed on graphite was heated in pure He and He containing O 2 or H 2 O atmosphere. The results obtained are as follows. It was proved that organic iodide was formed with organic radicals released from graphite even in He atmosphere. Thus, the interchange rate of inorganic iodide with organic iodide was remarkably decreased with prolonged preheat-treatment period at 1000degC. Organic iodide formed was easily decomposed by its recirculation into hot reaction tube kept at 900degC. When organic iodide was passed through powdered graphite bed, more than 70% was decomposed at 90degC. Oxygen and water vapour intermixed in He suppressed the interchange rate of inorganic iodide with organic iodide. These results suggest that organic iodide rarely exists in the pressure vessel under normal operating condition of HTTR, and, under hypothetical accident condition of HTTR, organic iodide fraction never exceeds the value used for a safety assessment of light water reactor. (author)

Peroxidase-catalyzed stabilization of 2,4-dichlorophenol in alkali-extracted soils.

Science.gov (United States)

Palomo, Mónica; Bhandari, Alok

2011-01-01

Horseradish peroxidase- (HRP) mediated stabilization of phenolic contaminants is a topic of interest due to its potential for remediation of contaminated soils. This study evaluated the sorption of 2,4-dichlorophenol (DCP) and its HRP-mediated stabilization in two alkali-extracted soils. Alkali extraction reduced the soil organic matter (SOM) contents of the geomaterials and enriched the residual SOM with humin C. Sorption of DCP on these sorbents was complete within 1 d. However, most of the sorbed DCP was removed from the geomaterials by water and methanol, suggesting weak solute-sorbent interactions. The addition of HRP resulted in the generation of DCP polymerization products (DPP), which partitioned between the aqueous and solid phases. The DPP phase distribution was rapid and complete within 24 h. Between 70 and 90% of the added DCP was converted to DPP and up to 43% of the initial aqueous phase contaminant was transformed into a residue that was resistant to extraction with methanol. Bound residues of DPP increased with initial aqueous phase solute concentration and remained fairly constant after 7 d of contact. Contaminant stabilization was noted to be high in the humin-mineral geomaterial. Results illustrate that HRP may be effective in stabilizing phenolic contaminants in subsoils that are likely to contain SOM enriched in humin C.

(e, 2e) triple differential cross sections of alkali and alkali earth atoms: Na, K and Mg, Ca

International Nuclear Information System (INIS)

Hitawala, U; Purohit, G; Sud, K K

2008-01-01

Recently low-energy measurements have been reported for alkali targets Na and K and alkali earth targets Mg and Ca in coplanar symmetric geometry. We report the results of our calculation of triple differential cross section (TDCS) for electron impact single ionization (i.e. (e, 2e) processes) of alkali atoms Na, K and alkali earth atoms Mg, Ca in coplanar symmetric geometry. We have performed the present calculations using the distorted-wave Born approximation (DWBA) formalism at intermediate incident electron energies used in the recently performed experiments. Ionization takes place from the valence shell for all the targets investigated and the outgoing electrons share the excess energy equally. We have also considered the effect of target polarization in our DWBA calculations which may be an important quantity at incident electron energies used in the present investigation. We find that the DWBA formalism is able to reproduce most of the trend of experimental data and may provide a future direction for further investigation of ionization process on alkali and alkali earth metals. It is also observed that the second-order effects are more important to understand the collision dynamics of (e, 2e) processes on alkali earth targets

Construction of thermionic alkali-ion sources

International Nuclear Information System (INIS)

Ul Haq, F.

1986-01-01

A simple technique is described by which singly charged alkali ions of K, Na, Li, Rb and Cs are produced by heating ultra-pure chemical salts of different alkali metals on tungsten filaments without employing a temperature measuring device. The character of alkali-ion currents at different heating powers and the remarkably constant ion emission current for prolonged periods are discussed. (author)

Local structure of alkalis in mixed-alkali borate glass to elucidate the origin of mixed-alkali effect

Directory of Open Access Journals (Sweden)

Yomei Tokuda

2015-12-01

Full Text Available We report the structural analysis of Na+ and Cs+ in sodium cesium borate crystals and glasses using 23Na and 133Cs magic-angle spinning nuclear magnetic resonance (MAS NMR spectroscopy. The composition dependence of NMR spectra of the borate was similar to that of the silicate: (1 the peak position of cesium borate crystals shifted to upfield for structures with larger Cs+ coordination numbers, (2 the MAS NMR spectra of xNa2O-yCs2O-3B2O3 (x = 0, 0.25, 0.5, 0.75, 1.0, x + y = 1 glass showed that the average coordination number (CN of both the alkali cations decreases with increasing Cs+/(Na+ + Cs+ ratio. However, the degree of decrement in borates is much smaller than that in silicates. We have considered that the small difference in CN is due to 4-coordinated B, because it is electrically compensated by the alkali metal ions resulting in the restriction of having various coordinations of O to alkali metal.

Determination of nanogram amounts of iodide by electrochemical isotope dilution analysis

International Nuclear Information System (INIS)

Gabrielsson, A.-B.; Beronius, P.

1976-01-01

A known quantity of iodide in ethanol as solvent was labelled with 131 I-and subsequently diluted with a predetermined amount of inactive iodide. Specific activities before and after the isotope dilution were established by anodically depositing small fractions of the halide in each sample on rotating silver micro electrodes and determining the activities of the electrodeposits. The lowest concentration of iodide used in any analysis was 1.10 -5 M. Further deposition studies revealed that iodide can be deposited with 1 100% current efficiency on the rotating silver micro electrode for concentration down to 2.4.10 -6 M. Electrodeposition studies for still lower concentrations have not yet been undertaken. These results suggest that amounts of iodide ion down to about 10 ng, and possibly still smaller quantitites, might be determined with the method developed. Amounts from 42 ng to 1 μg can be determined with an error of 2.5%. (T.G.)

Coprecipitation of alkali metal ions with calcium carbonate

International Nuclear Information System (INIS)

Okumura, Minoru; Kitano, Yasushi

1986-01-01

The coprecipitation of alkali metal ions Li + , Na + , K + and Rb + with calcium carbonate has been studied experimentally and the following results have been obtained: (1) Alkali metal ions are more easily coprecipitated with aragonite than with calcite. (2) The relationship between the amounts of alkali metal ions coprecipitated with aragonite and their ionic radii shows a parabolic curve with a peak located at Na + which has approximately the same ionic radius as Ca 2+ . (3) However, the amounts of alkali metal ions coprecipitated with calcite decrease with increasing ionic radius of alkali metals. (4) Our results support the hypothesis that (a) alkali metals are in interstitial positions in the crystal structure of calcite and do not substitute for Ca 2+ in the lattice, but (b) in aragonite, alkali metals substitute for Ca 2+ in the crystal structure. (5) Magnesium ions in the parent solution increase the amounts of alkali metal ions (Li + , Na + , K + and Rb + ) coprecipitated with calcite but decrease those with aragonite. (6) Sodium-bearing aragonite decreases the incorporation of other alkali metal ions (Li + , K + and Rb + ) into the aragonite. (author)

Studies on the alkali-silica reaction rim in a simplified calcium-alkali-silicate system

NARCIS (Netherlands)

Zheng, Kunpeng; Adriaensens, Peter; De Schutter, Geert; Ye, G.; Taerwe, Luc

2016-01-01

This work is intended to provide a better understanding about the properties and roles of the reaction rim in an alkali-silica reaction. A simplified calcium-alkali-silicate system was created to simulate the multiple interactions among reactive silica, alkaline solution and portlandite near the

Method of handling radioactive alkali metal waste

Science.gov (United States)

Wolson, R.D.; McPheeters, C.C.

Radioactive alkali metal is mixed with particulate silica in a rotary drum reactor in which the alkali metal is converted to the monoxide during rotation of the reactor to produce particulate silica coated with the alkali metal monoxide suitable as a feed material to make a glass for storing radioactive material. Silica particles, the majority of which pass through a 95 mesh screen or preferably through a 200 mesh screen, are employed in this process, and the preferred weight ratio of silica to alkali metal is 7 to 1 in order to produce a feed material for the final glass product having a silica to alkali metal monoxide ratio of about 5 to 1.

Method of handling radioactive alkali metal waste

International Nuclear Information System (INIS)

Mcpheeters, C.C.; Wolson, R.D.

1980-01-01

Radioactive alkali metal is mixed with particulate silica in a rotary drum reactor in which the alkali metal is converted to the monoxide during rotation of the reactor to produce particulate silica coated with the alkali metal monoxide suitable as a feed material to make a glass for storing radioactive material. Silica particles, the majority of which pass through a 95 mesh screen or preferably through a 200 mesh screen, are employed in this process, and the preferred weight ratio of silica to alkali metal is 7 to 1 in order to produce a feed material for the final glass product having a silica to alkali metal monoxide ratio of about 5 to 1

Infrared spectra of the gaseous iodides of chromium, iron and nickel

International Nuclear Information System (INIS)

Konings, R.J.M.; Booij, A.S.

1991-11-01

The infrared spectra of the vapours over chromium, iron and nickel di-iodide have been studied by high-temperature infrared spectroscopy. The gaseous molecules CrI 2 , FeI 2 and NiI 2 were all identified and the interpretation of the spectra is in agreement with a linear structure. Additional strong absorption bands in the spectra of the vapour phase above liquid CrI 2 and FeI 2 were assigned to dimeric (MI 2 ) 2 molecules. Valence force constants and thermodynamic quantities have been calculated. (author). 41 refs.; 4 figs.; 5 tabs

Method to remove methyl iodide131 gas

International Nuclear Information System (INIS)

Deitz, V.R.; Blachly, C.H.

1977-01-01

A two-stage impregnation process for charcoal is presented which is to be used for radioactive iodine or methyl iodide removal from the waste gas of a nuclear reactor. In the first stage, the coal is treated at pH 10 with an aqueous mixture of a salt of iodic acid (hypoiodite, iodate, or periodate) with iodine or iodide. In the second stage, impregnation with a tertiary amine occurs. The concentrations are chosen so that the charcoal will take up between 0.5 and 4% by weight of iodine. (UWI) [de

A plug flow model for chemical reactions and aerosol nucleation and growth in an alkali-containing flue gas

DEFF Research Database (Denmark)

Christensen, K. A.; Livbjerg, Hans

2000-01-01

multicomponent growth models are treated. The local gas phase composition is determined from a gas phase chemical equilibrium calculation combined with finite reaction rate kinetics for slower reactions. The model is useful in the analysis of boiler operation with respect to the formation of particles, HCl, SO2......The paper presents a numerical model for the simulation of gas to particle conversion and the chemical changes during cooling of a flue gas from the combustion of fuels rich in volatile alkali species. For the homogeneous nucleation of alkali species the model uses the classical theory modified...

A glucose bio-battery prototype based on a GDH/poly(methylene blue) bioanode and a graphite cathode with an iodide/tri-iodide redox couple.

Science.gov (United States)

Wang, Jen-Yuan; Nien, Po-Chin; Chen, Chien-Hsiao; Chen, Lin-Chi; Ho, Kuo-Chuan

2012-07-01

A glucose bio-battery prototype independent of oxygen is proposed based on a glucose dehydrogenase (GDH) bioanode and a graphite cathode with an iodide/tri-iodide redox couple. At the bioanode, a NADH electrocatalyst, poly(methylene blue) (PMB), which can be easily grown on the electrode (screen-printed carbon paste electrode, SPCE) by electrodeposition, is harnessed and engineered. We find that carboxylated multi-walled carbon nanotubes (MWCNTs) are capable of significantly increasing the deposition amount of PMB and thus enhancing the PMB's electrocatalysis of NADH oxidation and the glucose bio-battery's performance. The choice of the iodide/tri-iodide redox couple eliminates the dependence of oxygen for this bio-battery, thus enabling the bio-battery with a constant current-output feature similar to that of the solar cells. The present glucose bio-battery prototype can attain a maximum power density of 2.4 μW/cm(2) at 25 °C. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

The iodine/iodide redox couple at a platinum electrode

NARCIS (Netherlands)

Dane, L.M.; Janssen, L.J.J.; Hoogland, J.G.

1968-01-01

The I/iodide redox couple was studied on Pt in 0.5M H2SO4 by measuring the impedance as a function of frequency. From these measurements, the exchange c.d. j0 was derived according to Sluyters. The dependence of j0 on the reversible potential and the I and the iodide concns. was established. By

Thermodynamic properties of alkali borosilicate gasses and metaborates

International Nuclear Information System (INIS)

Asano, Mitsuru

1992-01-01

Borosilicate glasses are the proposed solidifying material for storing high level radioactive wastes in deep underground strata. Those have low melting point, and can contain relatively large amount of high level radioactive wastes. When borosilicate glasses are used for this purpose, they must be sufficiently stable and highly reliable in the vitrification process, engineered storage and the disposal in deep underground strata. The main vaporizing components from borosilicate glasses are alkali elements and boron. In this report, as for the vaporizing behavior of alkali borosilicate glasses, the research on thermodynamic standpoint carried out by the authors is explained, and the thermodynamic properties of alkali metaborates of monomer and dimer which are the main evaporation gases are reported. The evaporation and the activity of alkali borosilicate glasses, the thermodynamic properties of alkali borosilicate glasses, gaseous alkali metaborates and alkali metaborate system solid solution and so on are described. (K.I.)

Physical and optical studies in mixed alkali borate glasses with three types of alkali ions

International Nuclear Information System (INIS)

Samee, M.A.; Awasthi, A.M.; Shripathi, T.; Bale, Shashidhar; Srinivasu, Ch.; Rahman, Syed

2011-01-01

Research highlights: → We report, for the first time, the mixed alkali effect in the (40-x)Li 2 O-xNa 2 O-10K 2 O-50B 2 O 3 glasses through optical properties, density and modulated DSC studies. → Optical band gap (E opt ) and Urbach energy (ΔE) have been evaluated. → The values of E opt and ΔE show non-linear behavior with compositional parameter showing the mixed alkali effect. → The glass stability S is observed to be less which may be important for the present glasses as promising material for non-optical applications. - Abstract: So far only a handful of publications have been concerned with the study of the mixed alkali effect in borate glasses containing three types of alkali ions. In the present work, the mixed alkali effect (MAE) has been investigated in the glass system (40-x)Li 2 O-xNa 2 O-10K 2 O-50B 2 O 3 . (0 ≤ x ≤ 40 mol%) through density and modulated DSC studies. The density and glass transition temperature of the present glasses varies non-linearly exhibiting mixed alkali effect. The glass stability is observed to be less which may be important for the present glasses as promising material for non-optical applications. We report, for the first time, the mixed alkali effect in the present glasses through optical properties. From the absorption edge studies, the values of indirect optical band gap (E opt ), direct optical band gap and Urbach energy (ΔE) have been evaluated. The values of E opt and ΔE show non-linear behavior with compositional parameter showing the mixed alkali effect. The average electronic polarizability of oxide ions α O 2- , optical basicity Λ, and Yamashita-Kurosawa's interaction parameter A have been examined to check the correlations among them and bonding character. Based on good correlation among electronic polarizability of oxide ions, optical basicity and interaction parameter, the present Li 2 O-Na 2 O-K 2 O-B 2 O 3 glasses are classified as normal ionic (basic) oxides.

Auger recombination in sodium iodide

Science.gov (United States)

McAllister, Andrew; Kioupakis, Emmanouil; Åberg, Daniel; Schleife, André

2014-03-01

Scintillators are an important tool used to detect high energy radiation - both in the interest of national security and in medicine. However, scintillator detectors currently suffer from lower energy resolutions than expected from basic counting statistics. This has been attributed to non-proportional light yield compared to incoming radiation, but the specific mechanism for this non-proportionality has not been identified. Auger recombination is a non-radiative process that could be contributing to the non-proportionality of scintillating materials. Auger recombination comes in two types - direct and phonon-assisted. We have used first-principles calculations to study Auger recombination in sodium iodide, a well characterized scintillating material. Our findings indicate that phonon-assisted Auger recombination is stronger in sodium iodide than direct Auger recombination. Computational resources provided by LLNL and NERSC. Funding provided by NA-22.

Temperature dependent infrared spectroscopy of proton conducting alkali thio-hydroxogermanates

Energy Technology Data Exchange (ETDEWEB)

Karlsson, Maths; Matic, Aleksandar; Boerjesson, Lars [Department of Applied Physics, Chalmers University of Technology, SE-412 96 Goeteborg (Sweden); Nelson, Carly R.; Martindale, Chad A.; Martin, Steve W. [Department of Material Science and Engineering, 2220 Hoover Hall, Iowa State University of Science and Technology, Ames, IA 50011 (United States)

2006-04-15

We have investigated the thermal stability and reversibility upon dehydration and re-hydration of a novel class of proton conducting alkali thio-hydroxogermanates. The results indicate that no phase transitions or structural degradation occur in the temperature range 25 to 300C, and that repeated dehydration and subsequent re-hydration is a reversible process. The dehydration occurs gradually with increasing temperature, starting at about 80C. For temperatures above 180C the materials are dry, as all molecular water has been dried off. The dehydration process is shown to be reversible and the material can be rehydrated by exposure to air. The thermal stability and reversibility of the dehydration-rehydration process are attractive properties of functional materials, making the proton conducting alkali thio-hydroxogermanates to potential fuel cell electrolytes. (author)

ALKALI RESISTANT CATALYST

DEFF Research Database (Denmark)

2008-01-01

The present invention concerns the selective removal of nitrogen oxides (NOx) from gasses. In particular, the invention concerns a process, a catalyst and the use of a catalyst for the selective removal of nitrogen oxides in the presence of ammonia from gases containing a significant amount...... of alkali metal and/or alkali-earth compounds which process comprises using a catalyst combined of (i) a formed porous superacidic support, said superacidic support having an Hammett acidity stronger than Ho=-12, and (ii) a metal oxide catalytic component deposited on said superacidic support selected from...

Relation between the electroforming voltage in alkali halide-polymer diodes and the bandgap of the alkali halide

International Nuclear Information System (INIS)

Bory, Benjamin F.; Wang, Jingxin; Janssen, René A. J.; Meskers, Stefan C. J.; Gomes, Henrique L.; De Leeuw, Dago M.

2014-01-01

Electroforming of indium-tin-oxide/alkali halide/poly(spirofluorene)/Ba/Al diodes has been investigated by bias dependent reflectivity measurements. The threshold voltages for electrocoloration and electroforming are independent of layer thickness and correlate with the bandgap of the alkali halide. We argue that the origin is voltage induced defect formation. Frenkel defect pairs are formed by electron–hole recombination in the alkali halide. This self-accelerating process mitigates injection barriers. The dynamic junction formation is compared to that of a light emitting electrochemical cell. A critical defect density for electroforming is 10 25 /m 3 . The electroformed alkali halide layer can be considered as a highly doped semiconductor with metallic transport characteristics

40 CFR 721.4740 - Alkali metal nitrites.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkali metal nitrites. 721.4740... Substances § 721.4740 Alkali metal nitrites. (a) Chemical substances and significant new use subject to reporting. (1) The category of chemical substances which are nitrites of the alkali metals (Group IA in the...

Method for the safe disposal of alkali metal

International Nuclear Information System (INIS)

Johnson, T.R.

1977-01-01

Alkali metals such as those employed in liquid metal coolant systems can be safely reacted to form hydroxides by first dissolving the alkali metal in relatively inert metals such as lead or bismuth. The alloy thus formed is contacted with a molten salt including the alkali metal hydroxide and possibly the alkali metal carbonate in the presence of oxygen. This oxidizes the alkali metal to an oxide which is soluble within the molten salt. The salt is separated and contacted with steam or steam--CO 2 mixture to convert the alkali metal oxide to the hydroxide. These reactions can be conducted with minimal hydrogen evolution and with the heat of reaction distributed between the several reaction steps. 5 claims, 1 figure

Elastic modulus of the alkali-silica reaction rim in a simplified calcium-alkali-silicate system determined by nano-indentation

NARCIS (Netherlands)

Zheng, Kunpeng; Lukovic, M.; De Schutter, Geert; Ye, G.; Taerwe, Luc

2016-01-01

This work aims at providing a better understanding of the mechanical properties of the reaction rim in the alkali-silica reaction. The elastic modulus of the calcium alkali silicate constituting the reaction rim, which is formed at the interface between alkali silicate and Ca(OH)2 in a

Special features of the formation of high-conductivity phases of halides of alkali metals at superhigh pressures

International Nuclear Information System (INIS)

Babushkin, A.N.; Babushkina, G.V.

1999-01-01

The halides of alkali metals are the simplest crystals with the ionic nature of chemical bonds and are used widely as modelling materials in high-pressure physics. As a result of previous theoretical and experimental (optical, structural, electro-physical and shock-waves) investigations it was shown that these materials may be characterised by the overlapping of the valency and conduction bands and by the formation of groups of free charge carriers at pressures of the megabaric level. However, the authors know of no data on the direct investigations of the electrophysical properties of the halides of alkali metals at such high static pressures. The end of this investigation was to examine the temperature dependences of the electrical conductivity and thermal EMF of halides of alkali metals AX (A = Na, K, Rb, Cs, X = Cl, Br, I) in a wide temperature range at pressures from 10 to 50 GPa in order to reveal the general leisure since governing the change of their electronic structures, in particular, the transition to the state with the activation-type or metallic conductivity

A selective iodide ion sensor electrode based on functionalized ZnO nanotubes.

Science.gov (United States)

Ibupoto, Zafar Hussain; Khun, Kimleang; Willander, Magnus

2013-02-04

In this research work, ZnO nanotubes were fabricated on a gold coated glass substrate through chemical etching by the aqueous chemical growth method. For the first time a nanostructure-based iodide ion selective electrode was developed. The ZnO nanotubes were functionalized with miconazole ion exchanger and the electromotive force (EMF) was measured by the potentiometric method. The iodide ion sensor exhibited a linear response over a wide range of concentrations (1 × 10-6 to 1 × 10-1 M) and excellent sensitivity of -62 ± 1 mV/decade. The detection limit of the proposed sensor was found to be 5 × 10-7 M. The effects of pH, temperature, additive, plasticizer and stabilizer on the potential response of iodide ion selective electrode were also studied. The proposed iodide ion sensor demonstrated a fast response time of less than 5 s and high selectivity against common organic and the inorganic anions. All the obtained results revealed that the iodide ion sensor based on functionalized ZnO nanotubes may be used for the detection of iodide ion in environmental water samples, pharmaceutical products and other real samples.

A Selective Iodide Ion Sensor Electrode Based on Functionalized ZnO Nanotubes

Directory of Open Access Journals (Sweden)

Magnus Willander

2013-02-01

Full Text Available In this research work, ZnO nanotubes were fabricated on a gold coated glass substrate through chemical etching by the aqueous chemical growth method. For the first time a nanostructure-based iodide ion selective electrode was developed. The ZnO nanotubes were functionalized with miconazole ion exchanger and the electromotive force (EMF was measured by the potentiometric method. The iodide ion sensor exhibited a linear response over a wide range of concentrations (1 × 10−6 to 1 × 10−1 M and excellent sensitivity of –62 ± 1 mV/decade. The detection limit of the proposed sensor was found to be 5 × 10−7 M. The effects of pH, temperature, additive, plasticizer and stabilizer on the potential response of iodide ion selective electrode were also studied. The proposed iodide ion sensor demonstrated a fast response time of less than 5 s and high selectivity against common organic and the inorganic anions. All the obtained results revealed that the iodide ion sensor based on functionalized ZnO nanotubes may be used for the detection of iodide ion in environmental water samples, pharmaceutical products and other real samples.

Alkali binding in hydrated Portland cement paste

NARCIS (Netherlands)

Chen, Wei; Brouwers, Jos

2010-01-01

The alkali-binding capacity of C–S–H in hydrated Portland cement pastes is addressed in this study. The amount of bound alkalis in C–S–H is computed based on the alkali partition theories firstly proposed by Taylor (1987) and later further developed by Brouwers and Van Eijk (2003). Experimental data

Alkali-aggregate reactivity (AAR) facts book.

Science.gov (United States)

2013-03-01

This document provides detailed information on alkali-aggregate reactivity (AAR). It primarily discusses alkali-silica reaction (ASR), covering the chemistry, symptoms, test methods, prevention, specifications, diagnosis and prognosis, and mitigation...

The iodide sym-porter (NIS): new perspectives in nuclear oncology

International Nuclear Information System (INIS)

Pourcher, Th.; Lindenthal, S.; Basquin, C.; Ferhat, O.; Marsault, R.; Carrier, P.; Koulibaly, M.; Bussiere, F.; Darcourt, J.

2005-01-01

The sodium iodide sym-porter (NIS) is the plasma membrane protein that mediates uptake of iodide in the thyroid and other organs such as the stomach and the salivary gland. The cloning of its cDNA allows the targeting of NIS expression into any cell using gene therapy. This enables iodide uptake and thus NIS can be used as reporter imaging for live animals. More intriguingly, this new technique has potential using radio-iodide therapy to selectively destroy tumour cells. These two approaches employ common techniques in nuclear medicine. Many experiments on cultured cells and on animals have been carried out; they established clearly the advantages of this genetically targeted radiotherapy. Recent studies employing this therapy on multiple myeloma cell lines implanted in mice or on hepato-carcinoma-bearing rats, resulted in important tumour remission. However, additional studies on NIS regulation and the use of alternative radioisotopes transported by NIS are required to further develop this promising approach. (author)

Alkali depletion and ion-beam mixing in glasses

International Nuclear Information System (INIS)

Arnold, G.W.

1983-01-01

Ion-implantation-induced alkali depletion in simple alkali-silicate glasses (12M 2 O.88SiO 2 ) has been studied for implantations at room temperature and near 77K. Results are consistent with a mechanism for alkali removal, by heavy ion bombardment, based on radiation-enhanced migration and preferential removal of alkali from the outermost layers. Similar results were obtained for mixed-alkali glasses ((12-x)Cs 2 .O.xM 2 O.88SiO 2 ) where, in addition, a mixed-alkali effect may also be operative. Some preliminary experiments with ion implantation through thin Al films on SiO 2 glass and on a phosphate glass show that inter-diffusion takes place and suggest that this ion-mixing technique may be a useful method for altering the physical properties of glass surfaces

Ionic interactions in alkali-aluminium tetrafluoride clusters

International Nuclear Information System (INIS)

Akdeniz, Z.; Cicek, Z.; Karaman, A.; Pastore, G.; Tosi, M.P.

1999-08-01

Complex anion structures ((AlF 4 ) - , (AlF 5 ) 2- and (AlF 6 ) 3- ) coexist in liquid mixtures of aluminium trifluoride and alkali fluorides in composition-dependent relative concentrations and are known to interact with the alkali counterions. We present a comparative study of the static and vibrational structures of MAlF 4 molecules (with M = any alkali), with the aim of developing and testing a refined model of the ionic interactions for applications to the Al-M fluoride mixtures. We find that, whereas an edge-bridged coordination is strongly favoured for Li in LiAIF 4 , edge-bridging and face-bridging of the alkali ion become energetically equivalent as one moves from Na to the heavier alkalis. This result is sensitive to the inclusion of alkali polarizability and may be interpreted as implying (for M = K, Rb or Cs) almost free relative rotations of the M + and (AlF 4 ) - partners at temperatures of relevance to experiment. The consistency of such a viewpoint with electron diffraction data on vapours and with Raman spectra on melts is discussed. (author)

Evaluating iodide recycling inhibition as a novel molecular initiating event for thyroid axis disruption

Science.gov (United States)

The enzyme iodotyrosine deiodinase (dehalogenase, IYD) catalyzes iodide recycling and promotes iodide retention in thyroid follicular cells. Loss of function or chemical inhibition of IYD reduces available iodide for thyroid hormone synthesis, which leads to hormone insufficiency...

Efficient photoreductive decomposition of N-nitrosodimethylamine by UV/iodide process

International Nuclear Information System (INIS)

Sun, Zhuyu; Zhang, Chaojie; Zhao, Xiaoyun; Chen, Jing; Zhou, Qi

2017-01-01

Highlights: • N-nitrosodimethylamine (NDMA) was effectively decomposed by UV/iodide process. • NDMA was completely converted to nontoxic end products by UV/iodide process. • The photoreductive process was mainly attributed to the attack of hydrated electrons on the photoexcited NDMA. • The elimination of toxic intermediates was greatly enhanced as pH increased, but its effect on NDMA removal was negligible. - Abstract: N-nitrosodimethylamine (NDMA) has aroused extensive concern as a disinfection byproduct due to its high toxicity and elevated concentration levels in water sources. This study investigates the photoreductive decomposition of NDMA by UV/iodide process. The results showed that this process is an effective strategy for the treatment of NDMA with 99.2% NDMA removed within 10 min. The depletion of NDMA by UV/iodide process obeyed pseudo-first-order kinetics with a rate constant (k_1) of 0.60 ± 0.03 min"−"1. Hydrated electrons (e_a_q"−) generated by the UV irradiation of iodide were proven to play a critical role. Dimethylamine (DMA) and nitrite (NO_2"−) were formed as the main intermediate products, which completely converted to formate (HCOO"−), ammonium (NH_4"+) and nitrogen (N_2). Therefore, not only the high efficiencies in NDMA destruction, but the elimination of toxic intermediates make UV/iodide process advantageous. A photoreduction mechanism was proposed: NDMA initially absorbed photons to a photoexcited state, and underwent a cleavage of N−NO bond under the attack of e_a_q"−. The solution pH had little impact on NDMA removal. However, alkaline conditions were more favorable for the elimination of DMA and NO_2"−, thus effectively reducing the secondary pollution.

Behaviour of gaseous alkali compounds from coal gasification; Kaasumaisten alkaliyhdisteiden kaeyttaeytyminen kivihiilen kaasutuksessa

Energy Technology Data Exchange (ETDEWEB)

Nykaenen, J. [Imatran Voima Oy, Vantaa (Finland)

1996-12-01

In this project the behaviour of alkali compounds has been studied with a chemical equilibrium model. The goal is to evaluate the possibilities to remove the sodium and potassium compounds together with the fly ash particles by using a ceramic honeycomb filter. The studied processes include both CO{sub 2}/O{sub 2}- and air-blown gasification and combustion. The results show that the difference between the processes with flue gas recirculation and air-blown processes is small. This is due to that the equilibrium concentration of the dominant gaseous alkali compound, chloride, is more or less the same in both processes. This research project is closely connected to the EU-project coordinated by the Delft University of Technology (DUT). In that project alkali concentration of the fuel gas from a 1.6 MW pilot plant will be measured. During the next phase of this research the results from DUT will be compared with the results of this presentation. (author)

Evaluation of complexing agents and column temperature in ion chromatographic separation of alkali metals, alkaline earth metals and transition metals ion

International Nuclear Information System (INIS)

Kelkar, Anoop; Pandey, Ashish; Name, Anil B.; Das, D.K.; Behere, P.G.; Mohd Afzal

2015-01-01

The aim of ion chromatography method development is the resolution of all metal ions of interests. Resolution can be improved by changing the selectivity. Selectivity in chromatography can be altered by changes in mobile phase (eg eluent type, eluent strength) or through changes in stationary phase. Temperature has been used in altering the selectivity of particularly in reversed phase liquid chromatography and ion exchange chromatography. Present paper describe the retention behaviour of alkali metals, alkaline earth metals and transition metal ions on a silica based carboxylate function group containing analyte column. Alkali metals, alkaline earth metals and transition metal ions were detected by ion conductivity and UV-VIS detectors respectively

Controlled in-situ dissolution of an alkali metal

Science.gov (United States)

Jones, Jeffrey Donald; Dooley, Kirk John; Tolman, David Donald

2012-09-11

A method for the controllable dissolution of one or more alkali metals from a vessel containing a one or more alkali metals and/or one or more partially passivated alkali metals. The vessel preferably comprising a sodium, NaK or other alkali metal-cooled nuclear reactor that has been used. The alkali metal, preferably sodium, potassium or a combination thereof, in the vessel is exposed to a treatment liquid, preferably an acidic liquid, more preferably citric acid. Preferably, the treatment liquid is maintained in continuous motion relative to any surface of unreacted alkali metal with which the treatment liquid is in contact. The treatment liquid is preferably pumped into the vessel containing the one or more alkali metals and the resulting fluid is extracted and optionally further processed. Preferably, the resulting off-gases are processed by an off-gas treatment system and the resulting liquids are processed by a liquid disposal system. In one preferred embodiment, an inert gas is pumped into the vessel along with the treatment liquid.

Synthesis of formamidinium lead iodide perovskite bulk single crystal and its optical properties

Science.gov (United States)

Zheng, Hongge; Duan, Junjie; Dai, Jun

2017-07-01

Formamidinium lead iodide (FAPbI3) is a promising hybrid perovskite material for optoelectronic devices. We synthesized bulk single crystal FAPbI3 by a rapid solution crystallization method. X-ray diffraction (XRD) was performed to characterize the crystal structure. Temperature-dependent photoluminescence (PL) spectra of the bulk single crystal FAPbI3 were measured from 10 to 300 K to explain PL recombination mechanism. It shows that near band edge emission blueshifts with the temperature increasing from 10 to 120 K and from 140 K to room temperature, a sudden emission band redshift demonstrates near 140 K because of the phase transition from orthorhombic phase to cubic phase. From the temperature-dependent PL spectra, the temperature coefficients of the bandgap and thermal activation energies of FAPbI3 perovskite are fitted.

Estradiol decreases iodide uptake by rat thyroid follicular FRTL-5 cells

Directory of Open Access Journals (Sweden)

Furlanetto T.W.

2001-01-01

Full Text Available Estradiol has well-known indirect effects on the thyroid. A direct effect of estradiol on thyroid follicular cells, increasing cell growth and reducing the expression of the sodium-iodide symporter gene, has been recently reported. The aim of the present investigation was to study the effect of estradiol on iodide uptake by thyroid follicular cells, using FRTL-5 cells as a model. Estradiol decreased basal iodide uptake by FRTL-5 cells from control levels of 2.490 ± 0.370 to 2.085 ± 0.364 pmol I-/µg DNA at 1 ng/ml (P<0.02, to 1.970 ± 0.302 pmol I-/µg DNA at 10 ng/ml (P<0.003, and to 2.038 ± 0.389 pmol I-/µg DNA at 100 ng/ml (P<0.02. In addition, 4 ng/ml estradiol decreased iodide uptake induced by 0.02 mIU/ml thyrotropin from 8.678 ± 0.408 to 7.312 ± 0.506 pmol I-/µg DNA (P<0.02. A decrease in iodide uptake by thyroid cells caused by estradiol has not been described previously and may have a role in goiter pathogenesis.

Aqueous Stability of Alkali Superionic Conductors from First-Principles Calculations

International Nuclear Information System (INIS)

Radhakrishnan, Balachandran; Ong, Shyue Ping

2016-01-01

Ceramic alkali superionic conductor solid electrolytes (SICEs) play a prominent role in the development of rechargeable alkali-ion batteries, ranging from replacement of organic electrolytes to being used as separators in aqueous batteries. The aqueous stability of SICEs is an important property in determining their applicability in various roles. In this work, we analyze the aqueous stability of twelve well-known Li-ion and Na-ion SICEs using Pourbaix diagrams constructed from first-principles calculations. We also introduce a quantitative free-energy measure to compare the aqueous stability of SICEs under different environments. Our results show that though oxides are, in general, more stable in aqueous environments than sulfides and halide-containing chemistries, the cations present play a crucial role in determining whether solid phases are formed within the voltage and pH ranges of interest.

Removal efficiency of radioactive methyl iodide on TEDA-impregnated activated carbons

International Nuclear Information System (INIS)

Gonzalez-Garcia, C.M.; Gonzalez, J.F.; Roman, S.

2011-01-01

Activated carbons were prepared by different series of carbon dioxide and steam activation from walnut shells for their optimal use as radioactive methyl iodide adsorbents in Nuclear Plants. The knowledge of the most favourable textural characteristics of the activated carbons was possible by the previous study of the commercial activated carbon currently used for this purpose. In order to increase their methyl iodide affinity, the effect of triethylenediamine impregnation was studied at 5 and 10 wt.%. The results obtained indicated that in both cases the adsorption efficiency is markedly improved by the addition of impregnant, which allows the adsorbate uptake to occur not only by physical adsorption, via non-specific interactions (as in non-impregnated carbons) but also by the specific interaction of triethylenediamine with radioactive methyl iodide. Methyl iodide retention efficiencies up to 98.1% were achieved. (author)

First application of supported ionic liquid phase (SILP) catalysis for continuous methanol carbonylation

DEFF Research Database (Denmark)

Riisager, Anders; Jørgensen, Betina; Wasserscheid, Peter

2006-01-01

A solid, silica-supported ionic liquid phase (SILP) rhodium iodide Monsanto-type catalyst system, [BMIM][Rh(CO)(2)I-2]-[BMIM]I -SiO2, exhibits excellent activity and selectivity towards acetyl products in fixed-bed, continuous gas-phase methanol carbonylation.......A solid, silica-supported ionic liquid phase (SILP) rhodium iodide Monsanto-type catalyst system, [BMIM][Rh(CO)(2)I-2]-[BMIM]I -SiO2, exhibits excellent activity and selectivity towards acetyl products in fixed-bed, continuous gas-phase methanol carbonylation....

Effects of Aromatic Ammoniums on Methyl Ammonium Lead Iodide Hybrid Perovskite Materials

Directory of Open Access Journals (Sweden)

Jianli Yang

2017-01-01

Full Text Available The introduction of bulky ammoniums into methyl ammonium lead iodide hybrid perovskites (MAPbI3 has emerged as a promising strategy to improve the properties of these materials. In the present work, we studied the effects of several aromatic ammoniums onto the structural, electronic, and optical properties of MAPbI3. Although powder XRD data suggest that the bulky cations are not involved in the bulk phase of the MAPbI3, a surprisingly large effect of the bulky cations onto the photoluminescence properties was observed.

Effect of alkali ion on relaxation properties of binary alkali-borate glasses

International Nuclear Information System (INIS)

Lomovskoj, V.A.; Bartenev, G.M.

1992-01-01

Method of relaxation spectrometry were used to analyze the data on internal friction spectra of lithium, sodium, potassium and rubidium alkali-borate glasses in wide range of temperatures and frequencies. The nature of two relaxation processes was clarified: β m -process, related with mobility of alkaline metal cations, and α-process (vitrification), conditioned by system transformation from viscous-flow to vitreous state. It is shown that atomic-molecular mechanism of vitrification process changes when passing from vitreous B 2 O 3 to alkali-borate glasses

Charge transfer in gold--alkali-metal systems

International Nuclear Information System (INIS)

Watson, R.E.; Weinert, M.

1994-01-01

Based on conventional electronegativity arguments, gold--alkali-metal compounds are expected to be among the most ''ionic'' of metallic compounds. The concepts of ionicity and charge transfer are difficult to quantify. However, the changes in bonding in the 50/50 Au--alkali-metal systems between the elemental metals and the compounds are so severe that observations can readily be made concerning their character. The results, as obtained from self-consistent electronic-structure calculations, lead to the apparently odd observation that the electron density at the alkali-metal sites in the compound increases significantly and this involves high l componennts in the charge density. This increase, however, can be attributed to Au-like orbitals spatially overlapping the alkali-metal sites. In a chemical sense, it is reasonable to consider the alkali-metal transferring charge to these Au orbitals. While normally the difference in heats of formation between muffin-tin and full-potential calculations for transition-metal--transition-metal and transition-metal--main-group (e.g., Al) compounds having high site symmetry are small, for the gold--alkali-metal systems, the changes in bonding in the compounds cause differences of ∼0.5 eV/atom between the two classes of potential. Any serious estimate of the electronic structure in these systems must account for these aspherical bonding charges. The origin of the semiconducting behavior of the heavy-alkali-metal Au compounds is shown to arise from a combination of the Au-Au separations and the ionic character of the compounds; the light-alkali-metal Au compounds, with their smaller Au-Au separations, do not have a semiconducting gap. Core-level shifts and isomer shifts are also briefly discussed

Reaction of 1-bromo-3-chloropropane with tellurium and dimethyl telluride in the system of hydrazine hydrate-alkali; Reaktsiya 1-brom-3-khlorpropana s tellurom i dimetilditelluridom v sisteme gidrazin-gidrat-shcheloch'

Energy Technology Data Exchange (ETDEWEB)

Russavskaya, N V; Levanova, E P; Sukhomazova, Eh N; Grabel' nykh, V A; Elaev, A V; Klyba, L V; Zhanchipova, E R; Albanov, A I; Korotaeva, I M; Toryashinova, D S.D.; Korchevin, N A [SO RAN, Irkutskij Inst. Khimii imeni A.E. Favorskogo, Irkutsk (Russian Federation)

2006-05-15

A synthesis of oligomeric substance of thiocol type, the poly(trimethyleneditelluride), from 1-bromo-3-chloropropane and elemental tellurium is performed using a hydrazine hydrate-alkali system. Reductive splitting of the tellurocol followed by alkylation with methyl iodide give rise to preparation of bis(methyltelluro)propane, which was synthesized also from dimethyl telluride and 1,3-dihalopropanes using the N{sub 2}H{sub 4}{center_dot}H{sub 2}O/KOH system. The reaction products were characterized by elementary analysis, NMR, and IR spectra. Mass spectra of the synthesized low molecular weight organotellurium compounds are considered.

Efficient photoreductive decomposition of N-nitrosodimethylamine by UV/iodide process

Energy Technology Data Exchange (ETDEWEB)

Sun, Zhuyu; Zhang, Chaojie, E-mail: myrazh@tongji.edu.cn; Zhao, Xiaoyun; Chen, Jing; Zhou, Qi

2017-05-05

Highlights: • N-nitrosodimethylamine (NDMA) was effectively decomposed by UV/iodide process. • NDMA was completely converted to nontoxic end products by UV/iodide process. • The photoreductive process was mainly attributed to the attack of hydrated electrons on the photoexcited NDMA. • The elimination of toxic intermediates was greatly enhanced as pH increased, but its effect on NDMA removal was negligible. - Abstract: N-nitrosodimethylamine (NDMA) has aroused extensive concern as a disinfection byproduct due to its high toxicity and elevated concentration levels in water sources. This study investigates the photoreductive decomposition of NDMA by UV/iodide process. The results showed that this process is an effective strategy for the treatment of NDMA with 99.2% NDMA removed within 10 min. The depletion of NDMA by UV/iodide process obeyed pseudo-first-order kinetics with a rate constant (k{sub 1}) of 0.60 ± 0.03 min{sup −1}. Hydrated electrons (e{sub aq}{sup −}) generated by the UV irradiation of iodide were proven to play a critical role. Dimethylamine (DMA) and nitrite (NO{sub 2}{sup −}) were formed as the main intermediate products, which completely converted to formate (HCOO{sup −}), ammonium (NH{sub 4}{sup +}) and nitrogen (N{sub 2}). Therefore, not only the high efficiencies in NDMA destruction, but the elimination of toxic intermediates make UV/iodide process advantageous. A photoreduction mechanism was proposed: NDMA initially absorbed photons to a photoexcited state, and underwent a cleavage of N−NO bond under the attack of e{sub aq}{sup −}. The solution pH had little impact on NDMA removal. However, alkaline conditions were more favorable for the elimination of DMA and NO{sub 2}{sup −}, thus effectively reducing the secondary pollution.

Formation of lysinoalanine in egg white under alkali treatment.

Science.gov (United States)

Zhao, Yan; Luo, Xuying; Li, Jianke; Xu, Mingsheng; Tu, Yonggang

2016-03-01

To investigate the formation mechanism of lysinoalanine (LAL) in eggs during the alkali treatment process, NaOH was used for the direct alkali treatment of egg white, ovalbumin, and amino acids; in addition, the amount of LAL formed during the alkali treatment process was measured. The results showed that the alkali treatment resulted in the formation of LAL in the egg white. The LAL content increased with increasing pH and temperature, with the LAL content first increasing and then leveling off with increasing time. The amount of LAL formed in the ovalbumin under the alkali treatment condition accounted for approximately 50.51% to 58.68% of the amount of LAL formed in the egg white. Thus, the LAL formed in the ovalbumin was the main source for the LAL in the egg white during the alkali treatment process. Under the alkali treatment condition, free L-serine, L-cysteine, and L-cystine reacted with L-lysine to form LAL; therefore, they are the precursor amino acids of LAL formed in eggs during the alkali treatment process. © 2016 Poultry Science Association Inc.

Method of making alkali metal hydrides

Science.gov (United States)

Pecharsky, Vitalij K.; Gupta, Shalabh; Pruski, Marek; Hlova, Ihor; Castle, Andra

2017-05-30

A method is provided for making alkali metal hydrides by mechanochemically reacting alkali metal and hydrogen gas under mild temperature (e.g room temperature) and hydrogen pressure conditions without the need for catalyst, solvent, and intentional heating or cooling.

Analogy of the Coordination Chemistry of Alkaline Earth Metal and Lanthanide Ln²⁺ Ions: The Isostructural Zoo of Mixed Metal Cages [IM(OtBu)₄{Li(thf)}₄(OH)] (M=Ca, Sr, Ba, Eu), [MM′₆(OPh)₈(thf)₆] (M=Ca, Sr, Ba, Sm, Eu, M′=Li, Na), and their Derivatives with 1,2-Dimethoxyethane

OpenAIRE

Maudez, William; Meuwly, Markus; Fromm, Katharina M.

2008-01-01

As previously shown, alkali and alkaline earth metal iodides in nonaqueous, aprotic solvents behave like transition metal halides, forming cis- and trans-dihalides with various neutral O-donor ligands. These compounds can be used as precursors for the synthesis of new mixed alkali/alkaline earth metal aggregates. We show here that Ln²⁺ ions form isostructural cluster compounds. Thus, with LiOtBu, 50 % of the initial iodide can be replaced in MI₂, M=Ca, Sr, Ba, Eu, to generate the mixed-metal ...

Oxygen-hydrogen fuel cell with an iodine-iodide cathode - A concept

Science.gov (United States)

Javet, P.

1970-01-01

Fuel cell uses a porous cathode through which is fed a solution of iodine in aqueous iodide solution, the anode is a hydrogen electrode. No activation polarization appears on the cathode because of the high exchange-current density of the iodine-iodide electrode.

Ca-Fe and Alkali-Halide Alteration of an Allende Type B CAI: Aqueous Alteration in Nebular or Asteroidal Settings

Science.gov (United States)

Ross, D. K.; Simon, J. I.; Simon, S. B.; Grossman, L.

2012-01-01

Ca-Fe and alkali-halide alteration of CAIs is often attributed to aqueous alteration by fluids circulating on asteroidal parent bodies after the various chondritic components have been assembled, although debate continues about the roles of asteroidal vs. nebular modification processes [1-7]. Here we report de-tailed observations of alteration products in a large Type B2 CAI, TS4 from Allende, one of the oxidized subgroup of CV3s, and propose a speculative model for aqueous alteration of CAIs in a nebular setting. Ca-Fe alteration in this CAI consists predominantly of end-member hedenbergite, end-member andradite, and compositionally variable, magnesian high-Ca pyroxene. These phases are strongly concentrated in an unusual "nodule" enclosed within the interior of the CAI (Fig. 1). The Ca, Fe-rich nodule superficially resembles a clast that pre-dated and was engulfed by the CAI, but closer inspection shows that relic spinel grains are enclosed in the nodule, and corroded CAI primary phases interfinger with the Fe-rich phases at the nodule s margins. This CAI also contains abundant sodalite and nepheline (alkali-halide) alteration that occurs around the rims of the CAI, but also penetrates more deeply into the CAI. The two types of alteration (Ca-Fe and alkali-halide) are adjacent, and very fine-grained Fe-rich phases are associated with sodalite-rich regions. Both types of alteration appear to be replacive; if that is true, it would require substantial introduction of Fe, and transport of elements (Ti, Al and Mg) out of the nodule, and introduction of Na and Cl into alkali-halide rich zones. Parts of the CAI have been extensively metasomatized.

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)

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.

Electrodeposition as an alternate method for preparation of environmental samples for iodide by AMS

Energy Technology Data Exchange (ETDEWEB)

Adamic, M.L., E-mail: Mary.Adamic@inl.gov [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83402 (United States); Lister, T.E.; Dufek, E.J.; Jenson, D.D.; Olson, J.E. [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83402 (United States); Vockenhuber, C. [Laboratory of Ion Beam Physics, ETH Zurich, Otto-Stern-Weg 5, 8093 Zurich (Switzerland); Watrous, M.G. [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83402 (United States)

2015-10-15

This paper presents an evaluation of an alternate method for preparing environmental samples for {sup 129}I analysis by accelerator mass spectrometry (AMS) at Idaho National Laboratory. The optimal sample preparation method is characterized by ease of preparation, capability of processing very small quantities of iodide, and ease of loading into a cathode. Electrodeposition of iodide on a silver wire was evaluated using these criteria. This study indicates that the electrochemically-formed silver iodide deposits produce ion currents similar to those from precipitated silver iodide for the same sample mass. Precipitated silver iodide samples are usually mixed with niobium or silver powder prior to loading in a cathode. Using electrodeposition, the silver is already mixed with the sample and can simply be picked up with tweezers, placed in the sample die, and pressed into a cathode. The major advantage of this method is that the silver wire/electrodeposited silver iodide is much easier to load into a cathode.

Electrodeposition as an alternate method for preparation of environmental samples for iodide by AMS

International Nuclear Information System (INIS)

Adamic, M.L.; Lister, T.E.; Dufek, E.J.; Jenson, D.D.; Olson, J.E.; Vockenhuber, C.; Watrous, M.G.

2015-01-01

This paper presents an evaluation of an alternate method for preparing environmental samples for "1"2"9I analysis by accelerator mass spectrometry (AMS) at Idaho National Laboratory. The optimal sample preparation method is characterized by ease of preparation, capability of processing very small quantities of iodide, and ease of loading into a cathode. Electrodeposition of iodide on a silver wire was evaluated using these criteria. This study indicates that the electrochemically-formed silver iodide deposits produce ion currents similar to those from precipitated silver iodide for the same sample mass. Precipitated silver iodide samples are usually mixed with niobium or silver powder prior to loading in a cathode. Using electrodeposition, the silver is already mixed with the sample and can simply be picked up with tweezers, placed in the sample die, and pressed into a cathode. The major advantage of this method is that the silver wire/electrodeposited silver iodide is much easier to load into a cathode.

Electrical transport and phase stability in silver iodide-cadmium iodide

International Nuclear Information System (INIS)

Brightwell, J.W.; Buckley, C.N.; Miller, L.S.; Ray, B.

1983-01-01

A form of the equilibrium diagram for the system AgI-CdI 2 is proposed on the basis of thermal, X-ray diffractometer, and electrical conductivity data. Only one intermediate equilibrium phase, of composition Ag 2 CdI 4 , of tetragonal form with a 0 = 6.35 A and c 0 = 12.7 A is apparent; the previously reported hexagonal form of this composition being metastable. Low levels of CdI 2 are found to enhance the formation of the cubic, #betta#-form, af AgI and to increase the electrical conductivity. For various levels of CdI 2 inclusion in AgI, the principal increase in conductivity occurs in the region of 110 0 C instead of at 146 0 C as in pure AgI. (author)

Autoradiolytic decomposition and reductant-free sodium sup 124 I- and sup 123 I-iodide

Energy Technology Data Exchange (ETDEWEB)

Sajjad, M.; Lambrecht, R.M.; Bakr, S.A. (King Faisal Specialist Hospital and Research Centre, Riyadh (Saudi Arabia). Radionuclide and Cyclotron Operations)

1990-01-01

The presence of salts and metal cations in {sup 124}I- and {sup 123}I-sodium iodide solutions separated from {sup 124}Te targets promots autoradiolytic decomposition of iodide to several different iodine species dependent upon the chemical environment. The stabilization of the radioiodine as iodide by removal of trace salts and trace metal cations and in the absence of reducing agents is described. The high specific activity {sup 123}I- and {sup 124}I-iodide is suitable for labeling antibodies, proteins and radiopharmaceuticals. (orig.).

An investigation of sodium iodide solubility in sodium-stainless steel systems

International Nuclear Information System (INIS)

Sagawa, Norihiko; Tashiro, Suguru

1996-01-01

Sodium iodide and major constituents of stainless steel in sodium are determined by using the steel capsules to obtain a better understanding on contribution of the constituents to the apparent iodide solubility in sodium. The capsule loaded with 20 g sodium and 0.1 - 0.3 g powder of sodium iodide is heated at its upper part in a furnace and cooled at its bottom on brass plates to establish a large temperature gradient along the capsule tube. After a given period of equilibration, the iodide and constituents are fixed in solidified sodium by quick quenching of the capsules. Sodium samples are taken from the sectioned capsule tube and submitted to sodium dissolution by vaporized water for determination of the iodine and to vacuum distillation for determination of the metal elements. Iron and nickel concentrations are observed to be lower in the samples at higher iodine concentrations. Chromium and manganese concentrations are seen to be insensitive to the iodine concentrations. The observations can be interpreted by a model that sodium oxide combines with metal iodide in sodium to form a complex compound and with consideration that the compound will fall and deposit onto the bottom of the capsule by thermal diffusion. (author)

Relaxation of quadrupole orientation in an optically pumped alkali vapour

Energy Technology Data Exchange (ETDEWEB)

Bernabeu, E; Tornos, J

1985-04-01

The relaxation of quadrupole orientation (alignment) in an optically pumped alkali vapour is theoretically studied by taking into account the relaxation processes by alkali-buffer gas, alkali-alkali with spin exchange and alkali-cell wall (diffusion process) collisions. The relaxation transients of the quadrupole orientation are obtained by introducing a first-order weak-pumping approximation (intermediate pumping) less restrictive than the usually considered (zeroth order) one.

Electrical transport and phase stability in silver iodide-cadmium iodide

Energy Technology Data Exchange (ETDEWEB)

Brightwell, J.W.; Buckley, C.N.; Miller, L.S.; Ray, B. (Lanchester Polytechnic, Coventry (UK))

1983-03-16

A form of the equilibrium diagram for the system AgI-CdI/sub 2/ is proposed on the basis of thermal, X-ray diffractometer, and electrical conductivity data. Only one intermediate equilibrium phase, of composition Ag/sub 2/CdI/sub 4/, of tetragonal form with a/sub 0/ = 6.35 A and c/sub 0/ = 12.7 A is apparent; the previously reported hexagonal form of this composition being metastable. Low levels of CdI/sub 2/ are found to enhance the formation of the cubic, ..gamma..-form, af AgI and to increase the electrical conductivity. For various levels of CdI/sub 2/ inclusion in AgI, the principal increase in conductivity occurs in the region of 110 /sup 0/C instead of at 146 /sup 0/C as in pure AgI.

Thermal, mechanical and Raman studies on mixed alkali borotungstate glasses

Science.gov (United States)

Edukondalu, A.; Sathe, Vasant; Rahman, Syed; Siva Kumar, K.

2014-04-01

Mixed alkali borotungstate glasses with xLi2O-(30-x)Na2O-10WO3-60B2O3 (0 ≤ x ≤ 30) composition were prepared by melt quench technique. The amorphous phase of the prepared glass samples was conformed from their X-ray diffraction and SEM studies. Differential scanning calorimetry and Raman spectroscopic studies were employed to investigate the structure of all the prepared glasses. The elastic moduli and Debye temperature were calculated in terms of Makishima-Mackenzie model. Acting as complementary techniques, Raman measurement revealed that the network structure of the present glasses is mainly based on BO3 and BO4 units placed in different structural groups. Raman spectra confirms the presence of tungsten ions mainly as WO6 groups. In the present work, the mixed alkali effect (MAE) has been investigated in the above glass system through modulated DSC studies.

Mineralogy, geochemistry and expansion testing of an alkali-reactive basalt from western Anatolia, Turkey

International Nuclear Information System (INIS)

Copuroglu, Oguzhan; Andic-Cakir, Ozge; Broekmans, Maarten A.T.M.; Kuehnel, Radko

2009-01-01

In this paper, the alkali-silica reaction performance of a basalt rock from western Anatolia, Turkey is reported. It is observed that the rock causes severe gel formation in the concrete microbar test. It appears that the main source of expansion is the reactive glassy phase of the basalt matrix having approximately 70% of SiO 2 . The study presents the microstructural characteristics of unreacted and reacted basalt aggregate by optical and electron microscopy and discusses the possible reaction mechanism. Microstructural analysis revealed that the dissolution of silica is overwhelming in the matrix of the basalt and it eventually generates four consequences: (1) Formation of alkali-silica reaction gel at the aggregate perimeter, (2) increased porosity and permeability of the basalt matrix, (3) reduction of mechanical properties of the aggregate and (4) additional gel formation within the aggregate. It is concluded that the basalt rock is highly prone to alkali-silica reaction. As an aggregate, this rock is not suitable for concrete production.

Mineralogy, geochemistry and expansion testing of an alkali-reactive basalt from western Anatolia, Turkey

Energy Technology Data Exchange (ETDEWEB)

Copuroglu, Oguzhan, E-mail: O.Copuroglu@CiTG.TUDelft.NL [Delft University of Technology, Faculty of CiTG, Materials and Environment, Stevinweg 1, 2628CN, Delft (Netherlands); Andic-Cakir, Ozge [Ege University, Civil Engineering Dept., 35100 Bornova, Izmir (Turkey); Broekmans, Maarten A.T.M. [Geological Survey of Norway, Dept. of Mineral Characterization, N-7491 Trondheim (Norway); Kuehnel, Radko [Burgemeester Merkusstraat 5, 2645 NJ, Delfgauw (Netherlands)

2009-07-15

In this paper, the alkali-silica reaction performance of a basalt rock from western Anatolia, Turkey is reported. It is observed that the rock causes severe gel formation in the concrete microbar test. It appears that the main source of expansion is the reactive glassy phase of the basalt matrix having approximately 70% of SiO{sub 2}. The study presents the microstructural characteristics of unreacted and reacted basalt aggregate by optical and electron microscopy and discusses the possible reaction mechanism. Microstructural analysis revealed that the dissolution of silica is overwhelming in the matrix of the basalt and it eventually generates four consequences: (1) Formation of alkali-silica reaction gel at the aggregate perimeter, (2) increased porosity and permeability of the basalt matrix, (3) reduction of mechanical properties of the aggregate and (4) additional gel formation within the aggregate. It is concluded that the basalt rock is highly prone to alkali-silica reaction. As an aggregate, this rock is not suitable for concrete production.

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.

Discovery of aryl-tri-fluoroborates as potent sodium/iodide sym-porter (NIS) inhibitors

International Nuclear Information System (INIS)

Lecat-Guillet, N.; Ambroise, Y.

2008-01-01

The structure-based design of sodium/iodide sym-porter (NIS) inhibitors identified new active compounds. The organo-tri-fluoroborate shown was found to inhibit iodide uptake with an IC50 value of 0.4 μM on rat-derived thyroid cells. The biological activity is rationalized by the presence of the BF3 - ion as a minimal binding motif for substrate recognition at the iodide binding site. (authors)

Discovery of aryl-tri-fluoroborates as potent sodium/iodide sym-porter (NIS) inhibitors

Energy Technology Data Exchange (ETDEWEB)

Lecat-Guillet, N.; Ambroise, Y. [CEA, DSV, Dept Bioorgan Chem and Isotop Labelling, Inst Biol and Technol, iBiTecS, F-91191 Gif Sur Yvette (France)

2008-07-01

The structure-based design of sodium/iodide sym-porter (NIS) inhibitors identified new active compounds. The organo-tri-fluoroborate shown was found to inhibit iodide uptake with an IC50 value of 0.4 {mu}M on rat-derived thyroid cells. The biological activity is rationalized by the presence of the BF3{sup -} ion as a minimal binding motif for substrate recognition at the iodide binding site. (authors)

Milk Alkali and Hydrochlorothiazide: A Case Report

Directory of Open Access Journals (Sweden)

Babar Parvez

2011-01-01

Full Text Available Hypercalcemia is a relatively common clinical problem in both outpatient and inpatient settings. Primary pathophysiology is the entry of calcium that exceeds its excretion into urine or deposition in bone into circulation. Among a wide array of causes of hypercalcemia, hyperparathyroidism and malignancy are the most common, accounting for greater than 90 percent of cases. Concordantly, there has been a resurgence of milk-alkali syndrome associated with the ingestion of large amounts of calcium and absorbable alkali, making it the third leading cause of hypercalcemia (Beall and Scofield, 1995 and Picolos et al., 2005. This paper centers on a case of over-the-counter calcium and alkali ingestion for acid reflux leading to milk alkali with concordant use of thiazide diuretic for hypertension.

Vibrations of alkali metal overlayers on metal surfaces

International Nuclear Information System (INIS)

Rusina, G G; Eremeev, S V; Borisova, S D; Echenique, P M; Chulkov, E V; Benedek, G

2008-01-01

We review the current progress in the understanding of vibrations of alkalis adsorbed on metal surfaces. The analysis of alkali vibrations was made on the basis of available theoretical and experimental results. We also include in this discussion our recent calculations of vibrations in K/Pt(111) and Li(Na)/Cu(001) systems. The dependence of alkali adlayer localized modes on atomic mass, adsorption position and coverage as well as the dependence of vertical vibration frequency on the substrate orientation is discussed. The square root of atomic mass dependence of the vertical vibration energy has been confirmed by using computational data for alkalis on the Al(111) and Cu(001) substrates. We have confirmed that in a wide range of submonolayer coverages the stretch mode energy remains nearly constant while the energy of in-plane polarized modes increases with the increase of alkali coverage. It was shown that the spectrum of both stretch and in-plane vibrations can be very sensitive to the adsorption position of alkali atoms and substrate orientation

Early effects of external gamma irradiation on iodide metabolism in rat thyroid

International Nuclear Information System (INIS)

Niatsetskaya, Z.; Nadolnik, L.

2006-01-01

Full text of publication follows: The exposure of the thyroid gland to therapeutic doses of external gamma irradiation is frequently associated with thyroid dysfunction. Although late irradiation effects are well documented, little is still known about the early functional alterations in the thyroid subjected to radiation therapy. The aim of this study was to examine the early effect of single external gamma irradiation on iodide metabolism in the thyroid. The Wistar female rats were irradiated using a 60 Co installation with a constant capacity of 0.64 Gy/min. The doses used were 0.25, 0.5, 1, 2, 5 Gy. The animals were sacrificed after 24 hours following the irradiation. T he thyroid organ culture was cultivated during 24 h and than was irradiated with a single dose of 5 Gy. The thyroid tissue was assayed for thyro-peroxidase activity and concentrations of total, free and protein -binding iodide. It was shown that the 0.25 Gy irradiation depressed thyroid iodide uptake, which was manifested in decreasing total iodide by 25%. The same tendency was observed after the 0.5 Gy irradiation. In the 1, 2, 5 Gy groups, the concentrations of total and free iodide increased by 26 -34% and 50-68%, accordingly. The level of protein-binding iodide in these groups was within the control values. However, protein-binding/total iodide and protein binding/ free iodide ratios decreased by 17 -41%, suggesting inhibition of thyroglobulin iodination. Thyro-peroxidase (T.P.O.) plays a key role in thyroid hormone synthesis by catalyzing both the iodination of thyroglobulin and the coupling some of the iodo-tyrosyl residues. After 24 hours on irradiation, a 31.5-54% dose-dependent inhibition of T.P.O. activity was shown in the 1, 2 and 5 Gy groups. The irradiation of the rat thyroid organ culture with a single dose of 5 Gy also led to significant inhibition of T.P.O. by 56.91% after 2 hours. We compared the enzyme kinetics of thyro-peroxidase from thyroid microsomal fraction control and

Linearity and Reversibility of Iodide Adsorption on Sediments from Hanford, Washington Under Water Saturated Conditions

International Nuclear Information System (INIS)

Um, Wooyong; Serne, R. Jeffrey; Krupka, Kenneth M.

2004-01-01

A series of adsorption and desorption experiments were completed to determine the linearity of iodide adsorption, as a function of concentration, and its reversibility onto sediment for geochemical conditions germane to the proposed disposal of low-level radioactive waste by the U.S. Department of Energy's Immobilized Low Activity Waste (ILAW) program at the Hanford Site in southeastern Washington. Iodine-129 is predicted to be one of the top three long-term risk drivers based on past performance assessment conducted for the eventual disposal of the low-level portion of radioactive wastes currently stored in underground storage tanks at Hanford, because iodide exhibits little adsorption affinity to mineral surfaces resulting in high mobility in the subsurface environment. Adsorption experiments, conducted with Hanford formation sediments and groundwater spiked with dissolved 125I (as an analog tracer for 129I), indicated that iodide adsorption was very low at pH 7.5 and could be represented by a linear isotherm up to a total concentration of 100 mg/L dissolved iodide. The linearity of iodide adsorption up to concentrations of 100 mg/L validates the use of the linear Kd construct in transport models to predict the fate and transport of 129I in subsurface systems at Hanford. The results of desorption experiments indicated that up to 60% of adsorbed iodide was readily desorbed after 14 days by the same groundwater solution. Iodide adsorption was considered to be partially reversible or weakly binding on the sediments. Even though small amount of initial iodide is retarded by adsorption reactions at mineral-water interfaces, the weak adsorption affinity results in release of iodide when iodide free pore waters and ground waters contact the contaminated sediments in the vadose zone and aquifer systems

Alkali aggregate reactivity in concrete structures in western Canada

International Nuclear Information System (INIS)

Morgan, D.R.; Empey, D.

1989-01-01

In several regions of Canada, particularly parts of Ontario, Quebec and the Maritime Provinces, research, testing and evaluation of aged concrete structures in the field has shown that alkali aggregate reactivity can give rise to pronounced concrete deterioration, particularly in hydraulic structures subjected to saturation or alternate wetting and drying such as locks, dams, canals, etc. Concrete deterioration is mainly caused by alkali-silica reactions and alkali-carbonate reactions, but a third type of deterioration involves slow/late expanding alkali-silicate/silica reactivity. The alkalies NaOH and KOH in the concrete pore solutions are mainly responsible for attack on expansive rocks and minerals in concrete. Methods for evaluating alkali-aggregate reaction potential in aggregates, and field and laboratory methods for detecting deterioration are discussed. Examples of alkali-aggregate reactions in structures is western Canada are detailed, including a water reservoir at Canadian Forces Base Chilliwack in British Columbia, the Oldman River diversion and flume, the Lundbreck Falls Bridge, and the St Mary's Reservoir spillway, all in southern Alberta. Mitigative measures include avoidance of use of suspect aggregates, but if this cannot be avoided it is recommended to keep the total alkalies in the concrete as low as possible and minimize opportunities for saturation of concrete by moisture. 16 refs., 19 figs., 1 tab

Sodium iodide symporter: Its role in nuclear oncology

International Nuclear Information System (INIS)

Chung, June-Key

2004-01-01

Full text: Thyroid iodide uptake is basic to the clinical applications of radioiodine in diagnosis and therapy. Iodide uptake occurs across the membrane of thyroid follicular cells via an active transporter process mediated by the sodium/iodide symporter (NIS). The recent cloning of the gene encoding NIS enabled better characterization of the molecular mechanisms underlying the iodide transport, thus opening the way to clarify and expand its role in medicine. NIS contains 13 transmembrane segments, and its gene encodes a glycoprotein of 643 amino acids. Decreased NIS expression levels account for the reduced iodide uptake in thyroid carcinomas. We found that thyroid cancer patients with positive immunostaining for NIS responded to I-131 therapy better than did the patients with negative immunostaining. Thus, NIS gene can be used for radionuclide gene therapy. Targeted expression of functional NIS in cancer cells would enable these cells to concentrate iodide from plasma and would, therefore, offer the possibility of radioiodine therapy. We and others have shown that gene transfer of NIS into a variety of cell types confers increased radioiodine uptake up to several hundred-fold that of controls. There is great interest in exploring the possibility of NIS gene transfer to facilitate radioiodine therapy for non-thyroidal human cancers including hepatoma, prostate, breast, colon cancers as well as thyroid cancer. Recently, several approaches such as, targeted gene transfer, thyroid peroxidase gene co-transfection, retinoic acid treatment and Re-188 therapy instead of I-131, have been tried to improve this novel gene therapy. Imaging reporter gene is useful in non-invasively determining the location, duration and magnitude of transgene expression in living animal. Conventionally, HSV-tk and dopaminergic receptor (D2R) genes have been presented as possible imaging reporter genes. We proved that NIS could serve as an alternative imaging reporter gene. NIS has many

Iodine K-edge EXAFS analysis of iodide ion-cyclodextrin inclusion complexes in aqueous solution

International Nuclear Information System (INIS)

Kaneko, T; Ueda, M; Nagamatsu, S; Konishi, T; Fujikawa, T; Mizumaki, M

2009-01-01

We study the structure of inclusion complexes of α-, β-, γ-cyclodextrin with mono-iodide ion in aqueous solution by means of iodine K-edge EXAFS spectroscopy. The analysis is based on the assumption that two kinds of iodide ions exist in KI-cyclodextrin aqueous solution i.e. hydrated mono-iodide ions and one-one mono-iodide-cyclodextrin inclusion complexes. In KI-α-cyclodextrin system, iodine K-edge EXAFS analyse show that the average coordination number of the oxygen atoms in water molecules in the first hydration shell decreases as the fraction of included ions increases. This result suggests that dehydration process accompanies the formation of the inclusion complex. This is not found in the case of β-cyclodextrin, indicating that in this case the iodide ions are included together with the whole first hydration shell.

The Interfacial Transition Zone in Alkali-Activated Slag Mortars

Directory of Open Access Journals (Sweden)

Rackel eSan Nicolas

2015-12-01

Full Text Available The interfacial transition zone (ITZ is known to strongly influence the mechanical and transport properties of mortars and concretes. This paper studies the ITZ between siliceous (quartz aggregates and alkali activated slag binders in the context of mortar specimens. Backscattered electron images (BSE generated in an environmental scanning electron microscope (ESEM are used to identify unreacted binder components, reaction products and porosity in the zone surrounding aggregate particles, by composition and density contrast. X-ray mapping is used to exclude the regions corresponding to the aggregates from the BSE image of the ITZ, thus enabling analysis of only the binder phases, which are segmented into binary images by grey level discrimination. A distinct yet dense ITZ region is present in the alkali-activated slag mortars, containing a reduced content of unreacted slag particles compared to the bulk binder. The elemental analysis of this region shows that it contains a (C,N-A-S-H gel which seems to have a higher content of Na (potentially deposited through desiccation of the pore solution and a lower content of Ca than the bulk inner and outer products forming in the main binding region. These differences are potentially important in terms of long-term concrete performance, as the absence of a highly porous interfacial transition zone region is expected to provide a positive influence on the mechanical and transport properties of alkali-activated slag concretes.

Non-isovalent alkali metal ''substitution'' in YBa2Cu3O7-y granular ceramics

International Nuclear Information System (INIS)

Cloots, R.; Liege Univ.; Rulmont, A.; Pekala, M.; Liege Univ.; Laval, J.Y.; Bougrine, H.; Liege Univ.; Ausloos, M.

1995-01-01

The aim of this paper is to study the influence of non-isovalent ''doping'' in YBa 2 Cu 3 O 7-y in particular on its synthesis conditions and on the resistive properties both with and without a magnetic field. We concentrate on the study of possible alkali ions (Na, K, Cs) ''substitution'' at the barium sites. A low temperature sintering process is used in order to induce a reactive liquid phase. The final chemical composition is discussed as a function of the amount of the liquid phase. No alkali ion is substituted. Carbonate layers are present. However, this (lack of) ''substitution'' leads to induced vacancies and improved electrical transport properties which are as good as in highly pure materials. For conciseness the case of Na ''substitution'' only is illustrated. The use of such data in order to probe the microstructure is emphasized. (orig.)

40 CFR 721.5278 - Substituted naphthalenesulfonic acid, alkali salt.

Science.gov (United States)

2010-07-01

..., alkali salt. 721.5278 Section 721.5278 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.5278 Substituted naphthalenesulfonic acid, alkali salt. (a) Chemical... as a substituted naphthalenesulfonic acid, alkali salt (PMN P-95-85) is subject to reporting under...

40 CFR 721.8900 - Substituted halogenated pyridinol, alkali salt.

Science.gov (United States)

2010-07-01

..., alkali salt. 721.8900 Section 721.8900 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.8900 Substituted halogenated pyridinol, alkali salt. (a) Chemical... as substituted halogenated pyridinols, alkali salts (PMNs P-88-1271 and P-88-1272) are subject to...

Electrochemical insertion in solid media of alkali cations in carbonated host structures (polyacetylene, fullerene and graphite)

International Nuclear Information System (INIS)

Lemont, Sylvain

1994-01-01

This research thesis reports the investigation of electrochemical insertion of alkali cations in different host carbon containing structures (polyacetylene, fullerene, graphite). After a recall of the main characteristics of the three considered compounds, the author reports a bibliographical survey, describes the different compounds which can be used as solid electrolytes and explains the choice of the studied compounds with respect to their phase diagrams, ionic conductivity, electrochemical stability range. He describes the experimental methods, discusses the results obtained by intercalation of alkali cations (Li + , Na + , K + ) in polyacetylene. He discusses the electrochemical and structural results obtained on intercalation compounds of lithium and sodium ions in fullerene. The structures of several phases have been obtained by electron diffraction. Preliminary studies of electron energy loss spectrometry (EELS) are reported. The last part compares the results obtained on two types of graphite: pellets and spherules [fr

Clinical value of sodium iodide symporter

International Nuclear Information System (INIS)

Li Qian

2003-01-01

The sodium iodide symptorter (NIS) is a membrane glycoprotein that mediates iodide uptake in the thyroid gland and several extrathyroidal tissues. In addition to thyroid tissues, the expression of NIS is found in stomach, prostate, placenta and so on. Radioiodine-concentrating activity in thyroid tissues has allowed the use of radioiodine as a diagnostic and therapeutic agent for patients with thyroid disorders. However, some extrathyroid tissues also take up radioiodine, contributing to unwanted side effects of radioiodine therapy. Now that the molecule of NIS has been cloned and characterized, it may be possible to develop novel strategies to differentially modulate NIS expression and activity, enhancing it in target tissues and impeding it in others. It is also important to explore the use of NIS as an imaging reporter gene to monitor the expression profile of the transgene in transgenic mouse animal models and in patients undergoing gene therapy clinical trials

Thermal, mechanical and Raman studies on mixed alkali borotungstate glasses

Energy Technology Data Exchange (ETDEWEB)

Edukondalu, A. [Department of Physics, Osmania University, Hyderabad 500007 (India); Sathe, Vasant [Consortium for Scientific Research, Khandwa Road, Indore 452017 (India); Rahman, Syed [Department of Physics, Osmania University, Hyderabad 500007 (India); Siva Kumar, K., E-mail: siva193ou@gmail.com [Department of Physics, Osmania University, Hyderabad 500007 (India)

2014-04-01

Mixed alkali borotungstate glasses with xLi{sub 2}O–(30−x)Na{sub 2}O–10WO{sub 3}–60B{sub 2}O{sub 3} (0 ≤ x ≤ 30) composition were prepared by melt quench technique. The amorphous phase of the prepared glass samples was conformed from their X-ray diffraction and SEM studies. Differential scanning calorimetry and Raman spectroscopic studies were employed to investigate the structure of all the prepared glasses. The elastic moduli and Debye temperature were calculated in terms of Makishima–Mackenzie model. Acting as complementary techniques, Raman measurement revealed that the network structure of the present glasses is mainly based on BO{sub 3} and BO{sub 4} units placed in different structural groups. Raman spectra confirms the presence of tungsten ions mainly as WO{sub 6} groups. In the present work, the mixed alkali effect (MAE) has been investigated in the above glass system through modulated DSC studies.

Alkali trace elements in Gale crater, Mars, with ChemCam: Calibration update and geological implications

Science.gov (United States)

Payré, V.; Fabre, C.; Cousin, A.; Sautter, V.; Wiens, R. C.; Forni, O.; Gasnault, O.; Mangold, N.; Meslin, P.-Y.; Lasue, J.; Ollila, A.; Rapin, W.; Maurice, S.; Nachon, M.; Le Deit, L.; Lanza, N.; Clegg, S.

2017-03-01

The Chemistry Camera (ChemCam) instrument onboard Curiosity can detect minor and trace elements such as lithium, strontium, rubidium, and barium. Their abundances can provide some insights about Mars' magmatic history and sedimentary processes. We focus on developing new quantitative models for these elements by using a new laboratory database (more than 400 samples) that displays diverse compositions that are more relevant for Gale crater than the previous ChemCam database. These models are based on univariate calibration curves. For each element, the best model is selected depending on the results obtained by using the ChemCam calibration targets onboard Curiosity. New quantifications of Li, Sr, Rb, and Ba in Gale samples have been obtained for the first 1000 Martian days. Comparing these data in alkaline and magnesian rocks with the felsic and mafic clasts from the Martian meteorite NWA7533—from approximately the same geologic period—we observe a similar behavior: Sr, Rb, and Ba are more concentrated in soluble- and incompatible-element-rich mineral phases (Si, Al, and alkali-rich). Correlations between these trace elements and potassium in materials analyzed by ChemCam reveal a strong affinity with K-bearing phases such as feldspars, K-phyllosilicates, and potentially micas in igneous and sedimentary rocks. However, lithium is found in comparable abundances in alkali-rich and magnesium-rich Gale rocks. This very soluble element can be associated with both alkali and Mg-Fe phases such as pyroxene and feldspar. These observations of Li, Sr, Rb, and Ba mineralogical associations highlight their substitution with potassium and their incompatibility in magmatic melts.

Alkali-activated blast furnace slag-zeolite cements and concretes

International Nuclear Information System (INIS)

Rakhimov, R.; Rakhimova, N.

2012-01-01

The aim of this work has been the study of alkali-activated slag-zeolite cements and concretes based on them. Various compositions have been tested and some characteristics such as the compressive strength have been measured versus zeolite additions. A table lists the specific surface area and particle size distributions of different cements. The conclusions of the study are the following. First, alkali-activated slag cements and concretes based on them are effective for immobilization of radioactive wastes and the production of building structures, designed for high radiation load. Secondly, zeolite-containing mineral additions are able to increase the immobilization capacity and radiation resistance of alkali-activated blast furnace slag cements and concretes. Thirdly, the efficiency of different zeolite-containing additions - 10% to increase alkali-activated blast furnace slag-zeolite cement strength was established. It is with alkaline components of water-glass, sodium carbonate, sodium sulphate. Fourth, the effective way of introducing zeolite additions in alkali-activated blast furnace slag-zeolite cement is inter-grinding of the slag and addition. Increase in strength of alkali-activated blast furnace slag-zeolite cement stone is 40% higher than that of the stone of a mixture of separately milled components. Fifth, Alkali-activated blast furnace slag-zeolite cements with zeolite-containing additions with a compressive strength of 10.1 to 140 MPa; alkali-activated blast furnace slag-zeolite cements mortars with compressive strength from 35.2 to 97.7 MPa; alkali-activated blast furnace slag-zeolite cements concretes with compressive strength up to 84.5 MPa and frost resistant up to 800 cycles were obtained

Iodide-induced thyrotoxicosis in a thyroidectomized patient with metastatic thyroid carcinoma

Energy Technology Data Exchange (ETDEWEB)

Yoshinari, M.; Tokuyama, T.; Okamura, K.; Sato, K.; Kusuda, K.; Fujishima, M.

1988-04-15

An unusual case of iodide-induced thyrotoxicosis is documented in this article. The patient was a 64-year-old euthyroid man with acromegaly. He also had multiple follicular and papillary thyroid carcinomas with a metastatic lesion in the lumbar vertebrae. After a total thyroidectomy, he became slightly hypothyroid, and the lumbar lesion began to incorporate /sup 131/I by scintigraphy. When an iodine-containing contrast medium happened to be injected, a transient increase of serum thyroid hormone level was observed. After complete thyroid ablation with 83 mCi of /sup 131/I, the oral administration of 100 mg of potassium iodide for 7 days induced a prominent increase of serum thyroid hormone level. These findings indicated that the metastatic thyroid carcinoma could produce excess thyroid hormone insofar as a sufficient amount of iodide was given. Although this is the first report of such a case, iodide-induced thyrotoxicosis may not be rare in patients with thyroid carcinomas because the Wolff-Chaikoff effect is thought to be lost, and the organic iodinating activity and lysosomal protease activity are well-preserved.

Iodide-induced thyrotoxicosis in a thyroidectomized patient with metastatic thyroid carcinoma

International Nuclear Information System (INIS)

Yoshinari, M.; Tokuyama, T.; Okamura, K.; Sato, K.; Kusuda, K.; Fujishima, M.

1988-01-01

An unusual case of iodide-induced thyrotoxicosis is documented in this article. The patient was a 64-year-old euthyroid man with acromegaly. He also had multiple follicular and papillary thyroid carcinomas with a metastatic lesion in the lumbar vertebrae. After a total thyroidectomy, he became slightly hypothyroid, and the lumbar lesion began to incorporate 131 I by scintigraphy. When an iodine-containing contrast medium happened to be injected, a transient increase of serum thyroid hormone level was observed. After complete thyroid ablation with 83 mCi of 131 I, the oral administration of 100 mg of potassium iodide for 7 days induced a prominent increase of serum thyroid hormone level. These findings indicated that the metastatic thyroid carcinoma could produce excess thyroid hormone insofar as a sufficient amount of iodide was given. Although this is the first report of such a case, iodide-induced thyrotoxicosis may not be rare in patients with thyroid carcinomas because the Wolff-Chaikoff effect is thought to be lost, and the organic iodinating activity and lysosomal protease activity are well-preserved

The value of iodide as a parameter in the chemical characterisation of groundwaters

Science.gov (United States)

Lloyd, J. W.; Howard, K. W. F.; Pacey, N. R.; Tellam, J. H.

1982-06-01

Brackish and saline groundwaters can severely constrain the use of fresh groundwaters. Their chemical characterisation is important in understanding the hydraulic conditions controlling their presence in an aquifer. Major ions are frequently of limited value but minor ions can be used. Iodide in groundwater is particularly significant in many environments due to the presence of soluble iodine in aquifer matrix materials. Iodide is found in groundwaters in parts of the English Chalk aquifer in concentrations higher than are present in modern seawater. Its presence is considered as a indication of groundwater residence and is of use in the characterisation of fresh as well as saline waters. Under certain circumstances modern seawater intrusion into aquifers along English estuaries produces groundwaters which are easily identified due to iodide enrichment from estuarine muds. In other environments iodide concentrations are of value in distinguishing between groundwaters in limestones and shaly gypsiferous rocks as shown by a study in Qatar, while in an alluvial aquifer study in Peru iodide has been used to identify groundwaters entering the aquifer from adjacent granodiorites.

Lead iodide X-ray and gamma-ray spectrometers for room and high temperature operation

International Nuclear Information System (INIS)

Hermon, H.; James, R.B.; Lund, J.

1998-01-01

In this study the authors report on the results of the investigation of lead iodide material properties. The effectiveness of a zone refining purification method on the material purity is determined by ICP-MS and ICP-OES and correlated to the electrical and physical material properties. They show that this zone refining method is very efficient in removing impurities from lead iodide, and they also determine the segregation coefficient for some of these impurities. Triple axis X-ray diffraction (TAD) analysis has been used to determine the crystalline perfection of the lead iodide after applying various cutting, etching and fabrication methods. The soft lead iodide crystal was found to be damaged when cleaved by a razor blade, but by using a diamond wheel saw, followed by etching, the crystallinity of the material was much improved, as observed by TAD. Low temperature photoluminescence also indicates an improvement in the material properties of the purified lead iodide. Electrical properties of lead iodide such as carrier mobility, were calculated based on carrier-phonon scattering. The results for the electrical properties were in good agreement with the experimental data

Determination of iodide with 1,3-dibromo-5,5-dimethylhydantoin (DBH) in comparison with the ICl-method. Analytical methods of pharmacopeias with DBH in respect to environmental and economical concern. Part 3.

Science.gov (United States)

Hilp, M; Senjuk, S

2001-06-01

USP 1995 (The United States Pharmacopeia, 23rd Edit., (1995), potassium iodide p. 1265, sodium iodide p. 1424), PH. EUR. 1997 (European Pharmacopoeia, third ed., Council of Europe, Strasbourg, (1997), potassium iodide p. 1367, sodium iodide p. 1493) and JAP 1996 (The Japanes Pharmacopoeia, 13th ed. (1996), potassium iodide p. 578, sodium iodide p. 630) determine iodide with the ICl-method (J. Am. Chem. Soc. 25 (1903) 756-761; Z. Anorg. Chem. 36 (1903) 76-83; Fresenius Z. Anal. Chem. 106 (1936) 12-23; Arzneibuch-Kommentar, Wissenschaftliche Erläuterungen zum Europäischen Arzneibuch, Wissenschaftliche Verlagsgesellschaft mbH, Stuttgart, Govi-Verlag - Pharmazeutischer Verlag GmbH, Eschborn, 12th suppl. (1999), K10 p. 2), using chloroform, which is toxic and hazardous to environment. Without the application of chlorinated hydrocarbons USP 2000 (The United State Pharmacopeia, 24th ed. (2000), potassium iodide p. 1368, sodium iodide p. 1535) and Brit 1999 (British Pharmacopoeia London, (1999), Appendix VIII C, p. A162) titrate iodide with the redox indicator amaranth. A titration with potentiometric indication giving two end-points at the step of I(2) and [ICl(2)](-) is described. Due to the high concentration of hydrochloric acid required for the ICl-method, the determination with DBH (1,3-dibromo-5,5-dimethylhydantoin; 1,3-dibromo-5,5-dimethyl-2,4-imidazolidinedione) can be recommended and is performed easily. Similarly, the iodide content of gallamine triethiodide may be analyzed with DBH by application of a visual two-phase titration in water and ethyl acetate or with potentiometric indication in a mixture of 2-propanol and water. During the removal of the excess of DBH 4-bromo-triethylgallamine (2,2',2"-[1-bromo-benzene-2,3,4-triyltris(oxy)]N,N,N-triethylethanium) is formed.

Alkali elemental and potassium isotopic compositions of Semarkona chondrules

Science.gov (United States)

Alexander, C.M. O'D.; Grossman, J.N.

2005-01-01

We report measurements of K isotope ratios in 28 Semarkona chondrules with a wide range of petrologic types and bulk compositions as well as the compositions of CPX-mesostasis pairs in 17 type I Semarkona chondrules, including two chondrules with radial alkali zonation and 19 type II chondrules. Despite the wide range in K/Al ratios, no systematic variations in K isotopic compositions were found. Semarkona chondrules do not record a simple history of Rayleigh-type loss of K. Experimentally determined evaporation rates suggest that considerable alkali evaporation would have occurred during chondrule formation. Nevertheless, based on Na CPX-mesostasis distribution coefficients, the alkali contents of the cores of most chondrules in Semarkona were probably established at the time of final crystallization. However, Na CPX-mesostasis distribution coefficients also show that alkali zonation in type I Semarkona chondrules was produced by entry of alkalis after solidification, probably during parent body alteration. This alkali metasomatism may have gone to completion in some chondrules. Our preferred explanation for the lack of systematic isotopic enrichments, even in alkali depleted type I chondrule cores, is that they exchanged with the ambient gas as they cooled. ?? The Meteoritical Society, 2005.

Alkali-Resistant Mechanism of a Hollandite DeNOx Catalyst.

Science.gov (United States)

Hu, Pingping; Huang, Zhiwei; Gu, Xiao; Xu, Fei; Gao, Jiayi; Wang, Yue; Chen, Yaxin; Tang, Xingfu

2015-06-02

A thorough understanding of the deactivation mechanism by alkalis is of great importance for rationally designing improved alkali-resistant deNOx catalysts, but a traditional ion-exchange mechanism cannot often accurately describe the nature of the deactivation, thus hampering the development of superior catalysts. Here, we establish a new exchange-coordination mechanism on the basis of the exhaustive study on the strong alkali resistance of a hollandite manganese oxide (HMO) catalyst. A combination of isothermal adsorption measurements of ammonia with X-ray absorption near-edge structure spectra and X-ray photoelectron spectra reveals that alkali metal ions first react with protons from Brønsted acid sites of HMO via the ion exchange. Synchrotron X-ray diffraction patterns and extended X-ray absorption fine structure spectra coupled with theoretical calculations demonstrate that the exchanged alkali metal ions are subsequently stabilized at size-suitable cavities in the HMO pores via a coordination model with an energy savings. This exchange-coordination mechanism not only gives a wholly convincing explanation for the intrinsic nature of the deactivation of the reported catalysts by alkalis but also provides a strategy for rationally designing improved alkali-resistant deNOx catalysts in general.

Structural templating in a nonplanar phthalocyanine using single crystal copper iodide

OpenAIRE

Rochford, L. A. (Luke A.); Ramadan, Alexandra J.; Keeble, Dean S.; Ryan, Mary P.; Heutz, Sandrine; Jones, T. S. (Tim S.)

2015-01-01

Solution-grown copper iodide crystals are used as substrates for the templated growth of the nonplanar vanadyl phthalocyanine using organic molecular beam deposition. Structural characterization reveals a single molecular orientation produced by the (111) Miller plane of the copper iodide crystals. These fundamental measurements show the importance of morphology and structure in templating interactions for organic electronics applications.

Experimental study on iodine chemistry (EXSI) - Containment experiments with methyl iodide

Energy Technology Data Exchange (ETDEWEB)

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

2011-05-15

An experimental study on radiolytic decomposition of methyl iodide was conducted in co-operation between VTT and Chalmers University of Technology as a part of the NKS-R programs. In year 2008 the NROI project, a Nordic collaboration studying iodine chemistry in the containment, was started. During year 2008 (NROI-1) the radiolytic oxidation of elemental iodine was investigated and during 2009 (NROI-2), the radiolytic oxidation of organic iodine was studied. This project (NROI-3) is a continuation of the investigation of the oxidation of organic iodine. The project has been divided into two parts. 1. The aims of the first part were to investigate the effect of ozone and UV-radiation, in dry and humid conditions, on methyl iodide. 2. The second project was about gamma radiation (approx20 kGy/h) and methyl iodide in dry and humid conditions. 1. Experimental results showed that the methyl iodide concentration in the facility was reduced with increasing temperature and increasing UV-radiation intensity. Similar behaviour occurred when ozone was present in the system. Formed organic gas species during the decomposition of methyl iodide was mainly formaldehyde and methanol. The particle formation was instant and extensive when methyl iodide was exposed to ozone and/or radiation at all temperatures. The size of the formed primary particles was about 10 nm and the size of secondary particles was between 50-200 nm. From the SEM-EDX analyses of the particles, the conclusion was drawn that these were some kind of iodine oxides (I{sub xO{sub y}). However, the correct speciation of the formed particles was difficult to obtain because the particles melted and fused together under the electron beam. 2. The results from this sub-project are more inconsistent and hard to interpret. The particle formation was significant lesser than corresponding experiments when ozone/UV-radiation was used instead of gamma radiation. The transport of gaseous methyl iodide through the facility was

[Enhancement of anaerobic digestion of excess sludge by acid-alkali pretreatment].

Science.gov (United States)

Yuan, Guang-Huan; Zhou, Xing-Qiu; Wu, Jian-Dong

2012-06-01

In order to enhance the efficiency of anaerobic digestion of excess sludge, acid-alkali pretreatment method was studied. Three different pretreatment methods (alkali alone,acid-alkali, alkali-acid) were compared to investigate their impacts on hydrolysis and acidification of activated sludge. In addition, their influences on methane-producing in subsequent anaerobic digestion process were also studied. The results showed that the soluble chemical oxygen demand (SCOD) of alkaline treatment alone was about 16% higher than the combining of acid and alkali treatment, SCOD concentration increased to 5406.1 mg x L(-1) after 8 d pretreatment. After treated by acid (pH 4.0, 4 d) and alkali (pH 10.0, 4 d), the acetic acid production and its content in short-chain fatty acids (SCFAs) were higher than other pretreatment methods. And the acetic acid production (as COD/VSS) could reach 74.4 mg x g(-1), accounting for 60.5% of SCFAs. After acid-alkali pretreatment, the C: N ratio of the sludge mixed liquor was about 25, and the C: P ratio was between 35-40, which was more favorable than C: N and C: P ratio of alkali alone and alkali-acid to subsequent anaerobic digestion. The control experiments showed that, after acid-alkali pretreatment, anaerobic digestion cumulative methane yield (CH4/VSS(in)) reached to 136.1 mL x g(-1) at 15 d, which was about 2.5-, 1.6-, and 1.7-fold of the blank (unpretreated), alkali alone pretreatment and alkali-acid pretreatment, respectively. After acid-alkali pretreatment for 8 d and anaerobic digestion for 15 d, the removal efficiency of VSS was about 60.9%, and the sludge reduction effect was better than other pretreatments. It is obvious that the acid-alkali pretreatment method was more favorable to anaerobic digestion and sludge reduction.

40 CFR 721.1878 - Alkali metal alkyl borohydride (generic).

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkali metal alkyl borohydride... Specific Chemical Substances § 721.1878 Alkali metal alkyl borohydride (generic). (a) Chemical substance... alkali metal alkyl borohydride (PMN P-00-1089) is subject to reporting under this section for the...

Pair potentials and structure factors of liquid alkali metals

International Nuclear Information System (INIS)

Kumaravadivel, R.; Tosi, M.P.

1984-03-01

Measured structure factors of liquid alkali metals are examined in the framework of screened-pair-potentials theory. Information on the main attractive well in the effective pair potential is obtained from the structural data by an approximate method stemming from an optimized random phase treatment of the indirect ion-ion attraction. The results are compared with a variety of theoretical pair potentials in the cases of sodium and potassium, after a test of the method against computer simulation data on a model for rubidium. Results for the other alkali metals are also given and discussed. The small-angle scattering region is then examined in considerable detail, with special attention to the possibility of a linear term in a series expansion of the structure factor at very small momentum transfer. Although sensitivity to both the bare electron-ion coupling and the local field factor in the screening function is demonstrated and analyzed, no linear term of the magnitude reported in recent X-ray diffraction experiments is found in the present theoretical framework. (author)

Concrete alkali-silica reaction and nuclear radiation damage

International Nuclear Information System (INIS)

Ichikawa, Tsuneki

2008-01-01

The deterioration of concrete by alkali-silica reaction of aggregates (ASR) and the effect of nuclear radiations on the ASR have been reviewed based on our studies on the mechanism of ASR and the effect of nuclear radiations on the resistivity of minerals to alkaline solution. It has been found that the ASR is initiated by the attack of alkaline solution in concrete to silicious aggregates to convert them into hydrated alkali silicate. The consumption of alkali hydroxide by the aggregates induces the dissolution of Ca 2+ ions into the solution. The alkali silicate surrounding the aggregates then reacts with Ca 2+ ions to convert to insoluble tight and rigid reaction rims. The reaction rim allows the penetration of alkaline solution but prevents the leakage of viscous alkali silicate, so that alkali silicate generated afterward is accumulated in the aggregate to give an expansive pressure enough for cracking the aggregate and the surrounding concrete. The effect of nuclear radiation on the reactivity of quartz and plagioclase, a part of major minerals composing volcanic rocks as popular aggregates, to alkaline solution has been examined for clarifying whether nuclear radiations accelerates the ASR. It has been found that the irradiation of these minerals converts them into alkali-reactive amorphous ones. The radiation dose for plagioclase is as low as 10 8 Gy, which suggests that the ASR of concrete surrounding nuclear reactors is possible to be accelerated by nuclear radiation. (author)

Gravimetric determination of cadmium with o-phenanthroline and iodide

International Nuclear Information System (INIS)

Yoshida, Hitoshi; Mizuno, Kazunori; Taga, Mitsuhiko; Hikime, Seiichiro

1976-01-01

Cadmium forms insoluble mixed ligand complex with o-phenanthroline and iodide ions. By using the complex a new gravimetric method for the determination of cadmium was investigated. The recommended analytical procedure is as follows: Adjust pH value of a solution containing 5 to 45 mg cadmium to 4 with 3 M acetic acid-sodium acetate buffer solution. Add over threefold moles of potassium iodide to the solution and heat to just before boiling. To the solution add 0.1% ascorbic acid solution and then 0.1 M o-phenanthroline solution drop by drop in excess with stirring, and cool the mixture to room temperature. Filter the precipitates and wash first with 0.01% potassium iodide solution and then with water. Dry the precipitates at 110 0 C for two hours and weigh as Cd(o-phen) 2 I 2 (I). The gravimetric factor of the complex for cadmium is 0.1547. Chemical composition of the precipitate is variable when o-phenanthroline is added less than twofold moles to cadmium. Adding the o-phenanthroline solution 2.4-fold moles against cadmium, the ternary complex (I) precipitates quantitatively. Though a large excess of iodide ion in the solution contaminated the precipitate, the contamination was avoided when precipitation was carryed out at high temperature and in the presence of ascorbic acid. By the presented procedure 5 to 45 mg of cadmium are determined with a standard deviation of 0 C. (JPN)

Trapping radiodine, in the form of methyl iodide, on nuclear carbon

Energy Technology Data Exchange (ETDEWEB)

Nacapricha, D. [Mahidol Univ., Bangkok (Thailand); Taylor, C. [John Moores Univ., Liverpool (United Kingdom)

1996-12-31

Studies have been performed on potassium-iodide-impregnated charcoals of the type used in the nuclear industry for trapping radioiodine released during nuclear fission. The effects of various parameters on the trapping efficiency of methyl iodide have been investigated. A variation in particle size within a bulk charcoal caused poor precision in K value measurements because of differences in surface area, pore volume, and bed density, leading to differences in the deposition of the impregnant. Precision is improved by sieving the charcoal to a narrower size because smaller particles have a higher porosity. This finding is supported by surface area and pore measurements. Two methods of impregnation are compared by measuring K values and the deposition of potassium iodide. Charcoal impregnated by rotary evaporation exhibits both higher K values and higher potassium iodide contents than sprayed charcoal. Two designs of spraying drum are compared: a drum with helical vanes allows more efficient deposition and more uniform distribution of impregnant than a drum with axial vanes. A decrease in the K value with increasing humidity correlates with the available surface area. A similar correlation exists between water content and available pore volume. Aging of potassium-iodide-impregnated charcoal, caused by the formation of oxygen complexes on the surface, is associated with significant falls in K value. K values of charcoals also can be restored to at least their original values by heat treatment in the absence of air. 12 refs., 6 figs., 1 tab.

Functional activity of human sodium/iodide symporter in tumor cell lines

International Nuclear Information System (INIS)

Petrich, T.; Knapp, W.H.; Poetter, E.

2003-01-01

Aim: The sodium/iodide symporter (NIS) actively transports iodide into thyrocytes. Thus, NIS represents a key protein for diagnosis and radioiodine therapy of differentiated thyroid cancer. Additionally, in the future the NIS gene may be used for cancer gene therapy of non-thyroid-derived malignancies. In this study we evaluated the functionality of NIS with respect to iodide uptake in a panel of tumor cell lines and compared this to gene transfer efficiency. Methods: A human NIS-containing expression vector and reporter-gene vectors encoding and beta;-Galactosidase- or EGFP were used for transient transfection of 13 tumor cell lines. Following transfection measurements of NIS-mediated radioiodide uptake using Na 125 I and of transfection efficiency were performed. The latter included β;-Galactosidase activity measurements using a commercial kit and observation by fluorescence microscopy for EGFP expression. Results: In contrast to respective parental cells, most NIS-transfected cell lines displayed high, perchlorate-sensitive radioiodide uptake. Differences in radioiodide uptake between cell lines apparently corresponded to transfection efficiencies, as judged from reporter-gene assays. Conclusion: With respect to iodide uptake we provide evidence that NIS is functional in different cellular context. As iodide uptake capacity appears to be well correlated to gene transfer efficiency, cell type-specific actions on NIS (e. g. post-translational modification such as glycosylation) are not inhibitory to NIS function. Our data support the promising role of NIS in cancer gene therapy strategies. (orig.)

The utilization of alkali-treated melon husk by broilers.

Science.gov (United States)

Abiola, S S; Amalime, A C; Akadiri, K C

2002-09-01

The effects of alkali treatment on chemical constituents of melon husk (MH) and performance characteristics of broilers fed alkali-treated MH (ATMH) diets were investigated. The chemical analysis showed that alkali treatment increased the ash content of MH (from 15.70% to 16.86%) and reduced the crude fibre content (from 29.00% to 14.00%). Result of feed intake was superior on 30% alkali diet with a value of 100.14 g/bird/day. Body weight gain decreased with increase in the level of ATMH in the diet. Highest dressing percentage of 66.33% and best meat/bone ratio of 2.57 were obtained on 10% and 20% alkali diets, respectively. Dietary treatments had significant effect (P poultry carcases and chicken meat with favourable shelf life.

Phase equilibria of toluene/heptane with deep eutectic solvents based on ethyltriphenylphosphonium iodide for the potential use in the separation of aromatics from naphtha

International Nuclear Information System (INIS)

Kareem, Mukhtar A.; Mjalli, Farouq S.; Hashim, Mohd Ali; Hadj-Kali, Mohamed K.O.; Ghareh Bagh, Fatemeh Saadat; Alnashef, Inas M.

2013-01-01

Highlights: • Ionic liquid analogues are introduced as potential replacements for ionic liquids. • Deep eutectic solvents presented in this work were successful for extracting aromatics. • Hand correlation was applied to ascertain the experimental measurements. • The NRTL thermodynamic model was capable for correlating the LLE experimental data. -- Abstract: In this work, the liquid–liquid extraction of toluene from hydrocarbons mixtures (toluene/heptane) was investigated using deep eutectic solvents as solvents. Ethyltriphenylphosphonium iodide as a salt with either ethylene glycol or sulfolane as hydrogen-bond donors (HBDs) were utilized for synthesizing six DESs. (Liquid + liquid) equilibria data were determined experimentally for the ternary system (toluene + heptane + DES) at (30, 40, 50, and 60) °C and atmospheric pressure. Hand correlation was applied to establish the reliability of the experimental data. In many cases the correlation factor is found close to unity which indicates high reliability of the data. The selectivities and distribution coefficients were used to determine the suitability of these DESs as solvents for this extraction process. Higher selectivities than those published for sulfolane as a commercial solvent were observed. The DES made from ethyltriphenylphosphonium iodide and sulfolane at salt:HBD of 1:4 showed the best separation capability at 30 °C. Thus, it was further characterized by measuring its viscosity and refractive index at a range of temperatures to help understand its physical behaviour needed for process design. The non-random two-liquid (NRTL) model was applied successfully to correlate the experimental tie-lines and to calculate the phase compositions of the ternary systems. It has been found that the third non-randomness parameter varies linearly with the HBD number of moles

Experimental studies of caesium iodide aerosol condensation: theoretical interpretation

International Nuclear Information System (INIS)

Beard, A.M.; Benson, C.G.; Horton, K.D.; Buckle, E.R.

1990-07-01

Caesium iodide is predicted to be a significant source of fission product aerosols during the course of a severe accident in a pressurised water reactor (PWR). The nucleation and growth of caesium iodide aerosols have been studied using a plume chamber and the results compared with theoretical values calculated using the approach developed by Buckle for aerosol nucleation. The morphology of the particles was studied using scanning electron microscopy (SEM) and transmission optical microscopy (TOM), whilst the particle size distributions were determined from differential mobility (DMPS) and aerodynamic (APS) measurements. (author)

Alkali metal-refractory metal biphase electrode for AMTEC

Science.gov (United States)

Williams, Roger M. (Inventor); Bankston, Clyde P. (Inventor); Cole, Terry (Inventor); Khanna, Satish K. (Inventor); Jeffries-Nakamura, Barbara (Inventor); Wheeler, Bob L. (Inventor)

1989-01-01

An electrode having increased output with slower degradation is formed of a film applied to a beta-alumina solid electrolyte (BASE). The film comprises a refractory first metal M.sup.1 such as a platinum group metal, suitably platinum or rhodium, capable of forming a liquid or a strong surface adsorption phase with sodium at the operating temperature of an alkali metal thermoelectric converter (AMTEC) and a second refractory metal insoluble in sodium or the NaM.sup.1 liquid phase such as a Group IVB, VB or VIB metal, suitably tungsten, molybdenum, tantalum or niobium. The liquid phase or surface film provides fast transport through the electrode while the insoluble refractory metal provides a structural matrix for the electrode during operation. A trilayer structure that is stable and not subject to deadhesion comprises a first, thin layer of tungsten, an intermediate co-deposited layer of tungsten-platinum and a thin surface layer of platinum.

[Raman spectra of endospores of Bacillus subtilis by alkali stress].

Science.gov (United States)

Dong, Rong; Lu, Ming-qian; Li, Feng; Shi, Gui-yu; Huang, Shu-shi

2013-09-01

To research the lethal mechanism of spores stressed by alkali, laser tweezers Raman spectroscopy (LTRS) combined with principal components analysis (PCA) was used to study the physiological process of single spore with alkali stress. The results showed that both spores and germinated spores had tolerance with alkali in a certain range, but the ability of spores was obviously lower than that of spores due to the release of their Ca2+ -DPA which plays a key role in spores resistance as well as spores resistance to many stresses; A small amount of Ca2+ -DPA of spores was observed to release after alkali stress, however, the behavior of release was different with the normal Ca2+ -DPA release behavior induced by L-alanine; The data before and after alkali stress of the spores and g. spores with PCA reflected that alkali mainly injured the membrane of spores, and alkali could be easily enter into the inner structure of spores to damage the structure of protein backbone and injure the nucleic acid of spores. We show that the alkali could result in the small amount of Ca2+ -DPA released by destroying the member channel of spores.

A coupled channel study on a binding mechanism of positronic alkali atoms

International Nuclear Information System (INIS)

Kubota, Yoshihiro; Kino, Yasushi

2008-01-01

In order to investigate the binding mechanism of weakly bound states of positronic alkali atoms, we calculate the energies and wavefunctions using the Gaussian expansion method (GEM) where a positronium (Ps)-alkali ion channel and a positron-alkali atom channel are explicitly introduced. The energies of the bound states are updated using a model potential that reproduces well the observed energy levels of alkali atoms. The binding mechanism of the positronic alkali atom is analyzed by the wavefunctions obtained. The structure of the positronic alkali atom has been regarded as a Ps cluster orbiting the alkali ion, which is described by the Ps-alkali ion channel. We point out that the fraction having the positron-alkali atom configuration is small but plays an indispensable role for the weakly bound system

Alkali absorption and citrate excretion in calcium nephrolithiasis

Science.gov (United States)

Sakhaee, K.; Williams, R. H.; Oh, M. S.; Padalino, P.; Adams-Huet, B.; Whitson, P.; Pak, C. Y.

1993-01-01

The role of net gastrointestinal (GI) alkali absorption in the development of hypocitraturia was investigated. The net GI absorption of alkali was estimated from the difference between simple urinary cations (Ca, Mg, Na, and K) and anions (Cl and P). In 131 normal subjects, the 24 h urinary citrate was positively correlated with the net GI absorption of alkali (r = 0.49, p origin of hypocitraturia. However, the normal dependence was maintained in CDS and in idiopathic hypocitraturia, suggesting that reduced citrate excretion was largely dietary in origin as a result of low net alkali absorption (from a probable relative deficiency of vegetables and fruits or a relative excess of animal proteins).

The 4843 Alkali Metal Storage Facility Closure Plan

International Nuclear Information System (INIS)

1991-06-01

The 4843 AMSF has been used primarily to provide a centralized building to receive and store dangerous and mixed alkali metal waste, including sodium and lithium, which has been generated at the Fast Flux Test Facility and at various other Hanford Site operations that used alkali metals. Most of the dangerous and mixed alkali metal waste received consists of retired equipment from liquid sodium processes. The unit continues to store material. In general, only solid alkali metal waste that is water reactive is stored at the 4843 AMSF. The 4843 AMSF will be closed in a manner consistent with Ecology guidelines and regulations (WAC 173-303-610). The general closure procedure is detailed as follows

On-line alkali monitoring - Part 1; Kontinuerlig alkalimaetning - Etapp 1

Energy Technology Data Exchange (ETDEWEB)

Andersson, Christer; Ljung, P; Woxlin, H

1997-02-01

As a consequence of the increased knowledge of the environmental impact of combustion based heat and power generation, the use of renewable biofuels will be increased. An obstacle associated to biofuel combustion compared to other fuels is the large release of alkali. Alkali compounds in flue gases are known to cause severe operational problems. Three of the major problems are; fouling of superheating tubes (causing reduced heat transfer and possibly corrosion), agglomeration of the bed material in fluidized beds, and poisoning of SCR catalysts. Yet another alkali related problem arises when, in order to increase the electric efficiency of combustion power plants, combined-cycle technology is used. Alkali vapour present in the fuel gas for the gas turbine is condensed to particles which increase corrosion and erosion of the turbine blades. The research on ash related operational problems has to be extended in order to ensure future use of biofuels in heat and power generation. In all successful research, adequate tools are necessary. To investigate ash related problems the key issue is to be able to perform continuous alkali measurements. This pilot study has investigated the need of continuous alkali measurements, which alkali species are harmful in the different applications and also available instrumentation capable of measuring the specific alkali species. The report gives a short summary presenting alkali related operational problems. In addition a schematic overview is given, showing the alkali species that possibly can exist in various parts of the power plant. 48 refs, 13 figs, 4 tabs

Salts of alkali metal anions and process of preparing same

Science.gov (United States)

Dye, James L.; Ceraso, Joseph M.; Tehan, Frederick J.; Lok, Mei Tak

1978-01-01

Compounds of alkali metal anion salts of alkali metal cations in bicyclic polyoxadiamines are disclosed. The salts are prepared by contacting an excess of alkali metal with an alkali metal dissolving solution consisting of a bicyclic polyoxadiamine in a suitable solvent, and recovered by precipitation. The salts have a gold-color crystalline appearance and are stable in a vacuum at -10.degree. C. and below.

Synthesis and Characterization of Novel Ternary and Quaternary Alkali Metal Thiophosphates

KAUST Repository

Alahmary, Fatimah S.

2014-05-01

The ongoing development of nonlinear optical (NLO) crystals such as coherent mid-IR sources focuses on various classes of materials such as ternary and quaternary metal chalcophosphates. In case of thiophosphates, the connection between PS4-tetrahedral building blocks and metals gives rise to a broad structural variety where approximately one third of all known ternary (A/P/S) and quaternary (A/M/P/S) (A = alkali metal, M = metal) structures are acentric and potential nonlinear optical materials. The molten alkali metal polychalcophosphate fluxes are a well-established method for the synthesis of new ternary and quaternary thiophosphate and selenophosphate compounds. It has been a wide field of study and investigation through the last two decades. Here, the flux method is used for the synthesis of new quaternary phases containing Rb, Ag, P and S. Four new alkali metal thiophosphates, Rb4P2S10, RbAg5(PS4), Rb2AgPS4 and Rb3Ag9(PS4)4, have been synthesized successfully from high purity elements and binary starting materials. The new compounds were characterized by single crystal and powder X-ray diffraction, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), ultraviolet-visible (UV-VIS), Raman spectroscopy, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). These compounds show interesting structural variety and physical properties. The crystal structures feature 3D anionic framework built up of PS4 tetrahedral units and charge balanced by Ag and alkali metal cations. All prepared compounds are semiconductors with band gap between 2.3 eV to 2.6 eV and most of them are thermally stable up to 600ºC.

High alkali-resistant basalt fiber for reinforcing concrete

International Nuclear Information System (INIS)

Lipatov, Ya.V.; Gutnikov, S.I.; Manylov, M.S.; Zhukovskaya, E.S.; Lazoryak, B.I.

2015-01-01

Highlights: • Doping of basalt fiber with ZrSiO 4 increased its alkali resistance. • Alkali treatment results in formation of protective surface layer on fibers. • Morphology and chemical composition of surface layer were investigated. • Mechanical properties of fibers were analyzed by a Weibull distribution. • Zirconia doped basalt fibers demonstrate high performance in concrete. - Abstract: Basalt glasses and fibers with zirconia content in the range from 0 to 7 wt% were obtained using ZrSiO 4 as a zirconium source. Weight loss and tensile strength loss of fibers after refluxing in alkali solution were determined. Basalt fiber with 5.7 wt% ZrO 2 had the best alkali resistance properties. Alkali treatment results in formation of protective surface layer on fibers. Morphology and chemical composition of surface layer were investigated. It was shown that alkali resistance of zirconia doped basalt fibers is caused by insoluble compounds of Zr 4+ , Fe 3+ and Mg 2+ in corrosion layer. Mechanical properties of initial and leached fibers were evaluated by a Weibull distribution. The properties of basalt fibers with ZrSiO 4 were compared with AR-glass fibers. The performance of concrete with obtained fibers was investigated

Fate of alkali and trace metals in biomass gasification

International Nuclear Information System (INIS)

Salo, K.; Mojtahedi, W.

1998-01-01

The fate of alkali metals (Na, K) and eleven toxic trace elements (Hg, Cd, Be, Se, Sb, As, Pb, Zn, Cr, Co, Ni) in biomass gasification have been extensively investigated in Finland in the past ten years. The former due to the gas turbine requirements and the latter to comply with environmental regulations. In this paper the results of several experimental studies to measure Na and K in the vapor phase after the gas cooler of a simplified (air-blown) Integrated Gasification Combined-Cycle (IGCC) system are reported. Also, trace element emissions from an IGCC plant using alfalfa as the feedstock are discussed and the concentration of a few toxic trace metals in the vapor phase in the gasifier product gas are reported. (author)

Alkali Metal Cation Affinities of Anionic Main Group-Element Hydrides Across the Periodic Table

NARCIS (Netherlands)

Boughlala, Zakaria; Fonseca Guerra, Célia; Bickelhaupt, F. Matthias

2017-01-01

We have carried out an extensive exploration of gas-phase alkali metal cation affinities (AMCA) of archetypal anionic bases across the periodic system using relativistic density functional theory at ZORA-BP86/QZ4P//ZORA-BP86/TZ2P. AMCA values of all bases were computed for the lithium, sodium,

Muonium centers in the alkali halides

International Nuclear Information System (INIS)

Baumeler, H.; Kiefl, R.F.; Keller, H.; Kuendig, W.; Odermatt, W.; Patterson, B.D.; Schneider, J.W.; Savic, I.M.

1986-01-01

Muonium centers (Mu) in single crystals and powdered alkali halides have been studied using the high-timing-resolution transverse field μSR technique. Mu has been observed and its hyperfine parameter (HF) determined in every alkali halide. For the rocksalt alkali halides, the HF parameter A μ shows a systematic dependence on the host lattice constant. A comparison of the Mu HF parameter with hydrogen ESR data suggests that the Mu center is the muonic analogue of the interstitial hydrogen H i 0 -center. The rate of Mu diffusion can be deduced from the motional narrowing of the nuclear hyperfine interaction. KBr shows two different Mu states, a low-temperature Mu I -state and a high-temperature Mu II -state. (orig.)

Monitoring of fluoride and iodide levels in drinking water using ion selective electrodes

International Nuclear Information System (INIS)

Ahmed, R.; Viqar-Un-Nisa; Hussain, M.; Tanwir, R.; Qureshi, S.A.

2004-01-01

Fluoride and iodide, the most important constituents of drinking water are essential as well as toxic depending on their levels. For their analysis in water mostly ion-selective electrodes, spectrophotometry, titrimetry and coulometry etc; have been used and literature has been briefly reviewed. Ion-selective electrodes offer an efficient method for the measurement of the two halides and were mostly used during this work. Fabrication of these electrodes is briefly described. Comparison of results obtained by ion selective electrode and coulometry is given. Recoveries of the added fluoride ions from the samples were good. A large number of water samples from Rawalpindi-Islamabad area were analyzed for fluoride and iodide. Levels of fluoride and iodide from two main water reservoirs of Rawalpindi and Islamabad are reported before and after treatment. Both surface and ground water samples were analyzed and results are compared and discussed. Some samples from northern areas were also analyzed for iodide and fluoride and compared. Intake of fluoride and iodide from water of different areas is also compared. Water samples, which caused bone deformation in certain areas in Punjab due to excess fluoride, were also analyzed for fluoride and results are presented. (author)

Vapor pressure of selected organic iodides

Czech Academy of Sciences Publication Activity Database

Fulem, M.; Růžička, K.; Morávek, P.; Pangrác, Jiří; Hulicius, Eduard; Kozyrkin, B.; Shatunov, V.

2010-01-01

Roč. 55, č. 11 (2010), 4780-4784 ISSN 0021-9568 R&D Projects: GA ČR GA203/08/0217 Institutional research plan: CEZ:AV0Z10100521 Keywords : vapor pressure * static method * organic iodides Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.089, year : 2010

Alkali-slag cements for the immobilization of radioactive wastes

International Nuclear Information System (INIS)

Shi, C.; Day, R.L.

1996-01-01

Alkali-slag cements consist of glassy slag and an alkaline activator and can show both higher early and later strengths than Type III Portland cement, if a proper alkaline activator is used. An examination of microstructure of hardened alkali-slag cement pastes with the help of XRD and SEM with EDAX shows that the main hydration product is C-S-H (B) with low C/S ratio and no crystalline substances exist such as Ca(OH) 2 , Al (OH) 3 and sulphoaluminates. Mercury intrusion tests indicate that hardened alkali-slag cement pastes have a lower porosity than ordinary Portland cement, and contain mainly gel pores. The fine pore structure of hardened alkali-slag cement pastes will restrict the ingress of deleterious substances and the leaching of harmful species such as radionuclides. The leachability of Cs + from hardened alkali-slag cement pastes is only half of that from hardened Portland cement. From all these aspects, it is concluded that alkali-slag cements are a better solidification matrix than Portland cement for radioactive wastes

Chemistry of alkali cation exchanged faujasite and mesoporous NaX using alkyl halides and phosphates

Science.gov (United States)

Lee, Min-Hong

The purpose of this work was to increase the reactivity of Faujasite X (NaX) zeolite toward the reactive decontamination of materials subject to nucleophilic attack by means of zeolite cation optimization and by means of the synthesis of mesoporous Faujasite X. Primary alkyl halides and trialkyl phosphates have been the test materials on which the cation-optimized and mesoporous zeolites have been tested. In the alkali cation optimization work, reactions of methyl iodide and 1-chloropropane with alkali metal cation exchanged Faujasite zeolite X were investigated at room temperature. The reactivity of the framework and the product formation were shown to depend on zeolite framework counter-cation. A quantitative study of zeolite product formation has been carried out, primarily using solid-state NMR spectroscopy. Large alkali cations showed preference toward substitution chemistry. In contrast, alkyl halide exposed LiX and NaX zeolites underwent both substitution and elimination. Subsequently introduced water molecules led to hydrolysis of framework species that was sensitive to framework counter-cation. The mesoporous NaX zeolites work undertakes to test whether an improvement in surface chemical reactivity can be achieved by introducing mesopores into the already reactive nucleophilic microporous NaX zeolite. Incorporation of the polydiallyl dimethyl ammonium chloride (PDADMAC) template and the formation of mesopores in Faujasite X zeolite (NaX) were successful and well-characterized. The mesopores are proposed to have occurred from incorporation of the cationic PDADMAC polymer into the zeolite by compensating zeolite framework charge. Subsequent sodium cation exchange of calcined mesoporous NaX was shown to restore the chemical reactivity characteristic of as-synthesized NaX. Trialkyl organophosphorous compounds underwent substitution reactions. The reactivity of both microporous and mesoporous Faujasite zeolite X and the product formation was shown to depend on

Saccharification of gamma-ray and alkali pretreated lignocellulosics

International Nuclear Information System (INIS)

Begum, A.; Choudhury, N.

1988-01-01

Enzymic saccharification of gamma ray and alkali pretreated sawdust, rice straw, and sugar cane bagasse showed higher release of reducing sugar from pretreated substrates. By gamma ray treatment alone (500 kGy) reducing sugar release of 2.8, 9.2, and 10 g/l was obtained from 7.5% (w/v) sawdust, rice straw, and bagasse and the same substrates showed reducing sugar release of 4.2, 30, and 20 g/l respectively when treated with alkali (0.1 g/g). Combination of gamma ray with alkali treatment further increased the reducing sugar release to 10.2, 33, and 36 g/l from sawdust, rice straw, and bagasse respectively. The effects of gamma ray and alkali treatment on saccharification varied with the nature of the substrate

The alkali halide disk technique in infra-red spectrometry : Anomalous behaviour of some samples dispersed in alkali halide disks

NARCIS (Netherlands)

Tolk, A.

1961-01-01

Some difficulties encountered in the application of the alkali halide disk technique in infra-red spectrometry are discussed. Complications due to interaction of the sample with the alkali halide have been studied experimentally. It was found that the anomalous behaviour of benzoic acid, succinic

Alkali trace elements in Gale crater, Mars, with ChemCam: Calibration update and geological implications

International Nuclear Information System (INIS)

Payre, Valerie; Fabre, Cecile; Cousin, Agnes; Sautter, Violaine; Wiens, Roger Craig

2017-01-01

The Chemistry Camera (ChemCam) instrument onboard Curiosity can detect minor and trace elements such as lithium, strontium, rubidium, and barium. Their abundances can provide some insights about Mars' magmatic history and sedimentary processes. We focus on developing new quantitative models for these elements by using a new laboratory database (more than 400 samples) that displays diverse compositions that are more relevant for Gale crater than the previous ChemCam database. These models are based on univariate calibration curves. For each element, the best model is selected depending on the results obtained by using the ChemCam calibration targets onboard Curiosity. New quantifications of Li, Sr, Rb, and Ba in Gale samples have been obtained for the first 1000 Martian days. Comparing these data in alkaline and magnesian rocks with the felsic and mafic clasts from the Martian meteorite NWA7533—from approximately the same geologic period—we observe a similar behavior: Sr, Rb, and Ba are more concentrated in soluble- and incompatible-element-rich mineral phases (Si, Al, and alkali-rich). Correlations between these trace elements and potassium in materials analyzed by ChemCam reveal a strong affinity with K-bearing phases such as feldspars, K-phyllosilicates, and potentially micas in igneous and sedimentary rocks. However, lithium is found in comparable abundances in alkali-rich and magnesium-rich Gale rocks. This very soluble element can be associated with both alkali and Mg-Fe phases such as pyroxene and feldspar. Here, these observations of Li, Sr, Rb, and Ba mineralogical associations highlight their substitution with potassium and their incompatibility in magmatic melts.

Complexes in polyvalent metal - Alkali halide melts

International Nuclear Information System (INIS)

Akdeniz, Z.; Tosi, M.P.

1991-03-01

Experimental evidence is available in the literature on the local coordination of divalent and trivalent metal ions by halogens in some 140 liquid mixtures of their halides with alkali halides. After brief reference to classification criteria for main types of local coordination, we focus on statistical mechanical models that we are developing for Al-alkali halide mixtures. Specifically, we discuss theoretically the equilibrium between (AlF 6 ) 3- and (AlF 4 ) - complexes in mixtures of AlF 3 and NaF as a function of composition in the NaF-rich region, the effect of the alkali counterion on this equilibrium, the possible role of (AlF 5 ) 2- as an intermediate species in molten cryolite, and the origin of the different complexing behaviours of Al-alkali fluorides and chlorides. We also present a theoretical scenario for processes of structure breaking and electron localization in molten cryolite under addition of sodium metal. (author). 26 refs, 2 tabs

21 CFR 184.1265 - Cuprous iodide.

Science.gov (United States)

2010-04-01

... the following specific limitations: Category of food Maximum treatment level in food Functional use... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Cuprous iodide. 184.1265 Section 184.1265 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN...

Long term mechanical properties of alkali activated slag

Science.gov (United States)

Zhu, J.; Zheng, W. Z.; Xu, Z. Z.; Leng, Y. F.; Qin, C. Z.

2018-01-01

This article reports a study on the microstructural and long-term mechanical properties of the alkali activated slag up to 180 days, and cement paste is studied as the comparison. The mechanical properties including compressive strength, flexural strength, axis tensile strength and splitting tensile strength are analyzed. The results showed that the alkali activated slag had higher compressive and tensile strength, Slag is activated by potassium silicate (K2SiO3) and sodium hydroxide (NaOH) solutions for attaining silicate modulus of 1 using 12 potassium silicate and 5.35% sodium hydroxide. The volume dosage of water is 35% and 42%. The results indicate that alkali activated slag is a kind of rapid hardening and early strength cementitious material with excellent long-term mechanical properties. Single row of holes block compressive strength, single-hole block compressive strength and standard solid brick compressive strength basically meet engineering requirements. The microstructures of alkali activated slag are studied by X-ray diffraction (XRD). The hydration products of alkali-activated slag are assured as hydrated calcium silicate and hydrated calcium aluminate.

Ternary alkali-metal and transition metal or metalloid acetylides as alkali-metal intercalation electrodes for batteries

Science.gov (United States)

Nemeth, Karoly; Srajer, George; Harkay, Katherine C; Terdik, Joseph Z

2015-02-10

Novel intercalation electrode materials including ternary acetylides of chemical formula: A.sub.nMC.sub.2 where A is alkali or alkaline-earth element; M is transition metal or metalloid element; C.sub.2 is reference to the acetylide ion; n is an integer that is 0, 1, 2, 3 or 4 when A is alkali element and 0, 1, or 2 when A is alkaline-earth element. The alkali elements are Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs) and Francium (Fr). The alkaline-earth elements are Berilium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba), and Radium (Ra). M is a transition metal that is any element in groups 3 through 12 inclusive on the Periodic Table of Elements (elements 21 (Sc) to element 30 (Zn)). In another exemplary embodiment, M is a metalloid element.

Alkali metals and group IIA metals

International Nuclear Information System (INIS)

Fenton, D.E.

1987-01-01

This chapter on the coordination complexes of the alkali metals of group IIA starts with a historical perspective of their chemistry, from simple monodentate ligands, metal-β-diketonates to the macrocyclic polyethers which act as ligands to the alkali and akaline earth metals. Other macrocyclic ligands include quarterenes, calixarenes, porphyrins, phthalocyanines and chlorophylls. A section on the naturally occurring ionophores and carboxylic ionophores is included. (UK)

Mechanical filter for alkali atoms

CERN Document Server

Toporkov, D K

2000-01-01

A device for separating gases of different mass is discussed. Such a device could be used in a laser-driven spin exchange source of polarized hydrogen atoms to reduce the contamination of alkali atoms. A Monte Carlo simulation has shown that the suggested apparatus based on a commercial turbo pump could reduce by a factor of 10-15 the concentration of the alkali-metal atoms in the hydrogen flow from a laser driven polarized source. This would greatly enhance the effective polarization in hydrogen targets.

Tris(1,2-dimethoxyethane-κ2O,O′iodidocalcium iodide

Directory of Open Access Journals (Sweden)

Siou-Wei Ou

2012-02-01

Full Text Available In the title complex, [CaI(C4H10O23]I, the CaII atom is seven-coordinated by six O atoms from three 1,2-dimethoxyethane (DME ligands and one iodide anion in a distorted pentagonal–bipyramidal geometry. The I atom and one of the O atoms from a DME ligand lie in the axial positions while the other O atoms lie in the basal plane. The other iodide anion is outside the complex cation.

THE DISTRIBUTION OF COMMERCIAL CROWN ETHER DC18C6 AND THE EXTRACTION STUDY OF ALKALI AND EARTH ALKALI METALS

Directory of Open Access Journals (Sweden)

Bambang Rusdiarso

2010-06-01

Full Text Available Distribution of A and B isomers of crown-ether DC18C6 on their organic and water phases (chloride, nitrate and sulphocyanide salts and extraction of alkali and earth alkali metals has been studied. In LiCl 0.1 M environment, lithium extraction could be ignored. The presence of extracted potassium metal may affect the crown ether DC18C6 distribution albeit only a little. In KNO3 0.1 M environment, the distribution coefficient values (d were 6.1 and 10.3 for A and B isomers, respectively ; while in KCl  0.1 M environment the values were 4.9 and 11.8, respectively. In KSCN 0.1 M, d values for A and B isomers were 40.4 and 36.6, respectively, which were higher than the value obtained from both KNO3 and KCl  0.1 M environments. Caesium metal extraction using DC18C6 occurred weakly, up to only 5%. Strontium extraction using DC18C6 achieved better yield than the caesium extraction. The percentage of extraction increased under organic solvent according to the following: toluene (4% < chloroform (28% < TBP (35%.   Keywords: distribution, crown-ether DC18C6, extraction.

The influence of alkali promoters on coadsorbed molecules

International Nuclear Information System (INIS)

Umbach, E.

1986-01-01

A model has been suggested recently based on the results of an extensive study of the coadsorbate system CO + K on Ru(001). It is introduced and discussed in this article based on previous results and on results obtained very recently for a similar coadsorbate system, CO + K/Ni(111). This model is in competition with a variety of differing or similar ideas and interpretations which are mostly based on similar experimental results. Some of these other models postulate a lying-down, or strongly tilted, molecule in the presence of alkali atoms, at least at low coverages. The CO molecule is usually considered to be attached to the substrate and to be closely coadsorbed to the alkali neighbor(s) but sometimes even a vertical or horizontal adsorption on top of the alkali layer has been suggested. The interaction between alkali and CO has been described as indirect via the substrate or direct by forming a ''π''-bond between adjacent alkalis and CO molecules or even by forming an ionic K/sub x/-CO/sub y/ complex. Some authors prefer a model in which the main (or exclusive) interaction comes from a charge transfer from the donating alkali into the 2π orbital of the coadsorbed CO, thus, enhancing the C- metal and reducing the C-O bond strength

Process for the disposal of alkali metals

International Nuclear Information System (INIS)

Lewis, L.C.

1977-01-01

Large quantities of alkali metals may be safely reacted for ultimate disposal by contact with a hot concentrated caustic solution. The alkali metals react with water in the caustic solution in a controlled reaction while steam dilutes the hydrogen formed by the reaction to a safe level. 6 claims

A New Lead Iodide Perovskite based on Large Organic Cation for Solar Cell Application.

Science.gov (United States)

Ma, Chunqing; Shen, Dong; Lo, Ming Fai; Lee, Chun-Sing

2018-06-06

Methylammonium (CH3NH3+) and formamidinium ((NH2)2CH+) based lead iodide perovskites are currently the two commonly used organic-inorganic lead iodide perovskites for solar cell application. Till now, there is still no alternative organic cations, which can produce perovskites with bandgaps spanning the visible spectrum (i.e. solar cell application. Here, a new perovskite using large propane-1,3-diammonium cation (n-Pr(NH3)22+) with a chemical structure of (n-Pr(NH3)2)0.5PbI3 is demonstrated. X-ray diffraction (XRD) result shows that the new perovskite exhibits a three-dimensional (3D), tetragonal phase. The bandgap of the new perovskite is ~ 1.6 eV, which is desirable for photovoltaic application. A (n-Pr(NH3)2)0.5PbI3 perovskite solar cell (PSC) yields a power conversion efficiency (PCE) of 5.1%. More importantly, this new perovskite is composed of larger hydrophobic cation that provides a better moisture resistance compared to CH3NH3PbI3 perovskite. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Potentiometric determination of iodides in urine

International Nuclear Information System (INIS)

Gikolaev, B.A.; Primakova, L.N.; Rakhman'ko, E.M.

1996-01-01

Variants of potentiometric method: determination using a calibrations plot, the Gran method, and the double addition method are considered. The method of double additions of the test solution to the reference one is suggested as the most favorable method of determining iodides in urine under clinical laboratory conditions. Refs. 5, tabs. 2

Mineralization dynamics of metakaolin-based alkali-activated cements

International Nuclear Information System (INIS)

Gevaudan, Juan Pablo; Campbell, Kate M.; Kane, Tyler J.; Shoemaker, Richard K.; Srubar, Wil V.

2017-01-01

This paper investigates the early-age dynamics of mineral formation in metakaolin-based alkali-activated cements. The effects of silica availability and alkali content on mineral formation were investigated via X-ray diffraction and solid-state 29 Si magic-angle spinning nuclear magnetic resonance spectroscopy at 2, 7, 14, and 28 days. Silica availability was controlled by using either liquid- (immediate) or solid-based (gradual) sodium silicate supplements. Mineral (zeolitic) and amorphous microstructural characteristics were correlated with observed changes in bulk physical properties, namely shrinkage, density, and porosity. Results demonstrate that, while alkali content controls the mineralization in immediately available silica systems, alkali content controls the silica availability in gradually available silica systems. Immediate silica availability generally leads to a more favorable mineral formation as demonstrated by correlated improvements in bulk physical properties.

The solvent extraction of alkali metal ions with β-diketones

International Nuclear Information System (INIS)

Munakata, Megumu; Niina, Syozo; Shimoji, Noboru

1974-01-01

This work was undertaken to investigate effects of solvent and chelating-agent on the solvent extraction of alkali metal ions by seven β-diketones, acetylacetone (Acac), benzoylacetone (BzA), dipivaloylmethane (DPM), dibenzoylmethane (DBM), thenoyltrifluoloacetone (TTA), benzoyltrifluoroacetone (BFA) and hexafluoroacetylacetone (HFA), and to separate lithium from alkali metals. The extraction of alkali metals increase with increasing donor power of the solvent: i.e., benzene Na>K>Rb>Cs, which is also the order in which the adduct formation of these β-diketone chelates with donor solvents increase. The adduct formations between β-diketone chelates of alkali metals and donor solvents markedly enhance the solubilities of the chelates in solvents and, consequently, the extractabilities of alkali metals with β-diketones. Lithium was extracted with TTA in ether at such a low base concentration that sodium, potassium, rubidium and cesium were hardly extracted, and this enabled to separate lithium from other metals by the use of rubidium hydroxide (0.02 M). An attempt has been made to isolate alkali metal β-diketone chelates and some chelates have been obtained as crystals. The infrared absorption bands arising from C=O and C.=C of TTA shift to lower frequencies in the alkali metal chelates with TTA, and consequently, β-diketones is suggested to coordinate to alkali metal as a bidentate ligand. (JPN)

Evaluation of optimal silver amount for the removal of methyl iodide on silver-impregnated adsorbents

International Nuclear Information System (INIS)

Park, G.I.; Cho, I.H.; Kim, J.H.; Oh, W.Z.

2001-01-01

The adsorption characteristics of methyl iodide generated from the simulated off-gas stream on various adsorbents such as silver-impregnated zeolite (AgX), zeocarbon and activated carbon were investigated. An extensive evaluation was made on the optimal silver impregnation amount for the removal of methyl iodide at temperatures up to 300 deg. C. The degree of adsorption efficiency of methyl iodide on silver-impregnated adsorbent is strongly dependent on impregnation amount and process temperature. A quantitative comparison of adsorption efficiencies on three adsorbents in a fixed bed was investigated. The influence of temperature, methyl iodide concentration and silver impregnation amount on the adsorption efficiency is closely related to the pore characteristics of adsorbents. It shows that the effective impregnation ratio was about 10wt%, based on the degree of silver utilization for the removal of methyl iodide. The practical applicability of silver-impregnated zeolite for the removal of radioiodine generated from the DUPIC process was consequently proposed. (author)

Determination of iodide, iodate and organo-iodine in waters with a new total organic iodine measurement approach.

Science.gov (United States)

Gong, Tingting; Zhang, Xiangru

2013-11-01

The dissolved iodine species that dominate aquatic systems are iodide, iodate and organo-iodine. These species may undergo transformation to one another and thus affect the formation of iodinated disinfection byproducts during disinfection of drinking waters or wastewater effluents. In this study, a fast, sensitive and accurate method for determining these iodine species in waters was developed by derivatizing iodide and iodate to organic iodine and measuring organic iodine with a total organic iodine (TOI) measurement approach. Within this method, organo-iodine was determined directly by TOI measurement; iodide was oxidized by monochloramine to hypoiodous acid and then hypoiodous acid reacted with phenol to form organic iodine, which was determined by TOI measurement; iodate was reduced by ascorbic acid to iodide and then determined as iodide. The quantitation limit of organo-iodine or sum of organo-iodine and iodide or sum of organo-iodine, iodide and iodate was 5 μg/L as I for a 40 mL water sample (or 2.5 μg/L as I for an 80 mL water sample, or 1.25 μg/L as I for a 160 mL water sample). This method was successfully applied to the determination of iodide, iodate and organo-iodine in a variety of water samples, including tap water, seawater, urine and wastewater. The recoveries of iodide, iodate and organo-iodine were 91-109%, 90-108% and 91-108%, respectively. The concentrations and distributions of iodine species in different water samples were obtained and compared. Copyright © 2013 Elsevier Ltd. All rights reserved.

Behaviour of organic iodides under pwr accident conditions

International Nuclear Information System (INIS)

Alm, M.

1982-01-01

Laboratory experiments were performed to study the behaviour of radioactive methyl iodide under PWR loss-of-coolant conditions. The pressure relief equipment consisted of an autoclave for simulating the primary circuit and of an expansion vessel for simulating the conditions after a rupture in the reactor coolant system. After pressure relief, the composition of the CH 3 sup(127/131)I-containing steam-air mixture within the expansion vessel was analysed at 80 0 C over a period of 42 days. On the basis of the values measured and of data taken from the literature, both qualitative and quantitative assessments have been made as to the behaviour of radioactive methyl iodide in the event of loss-of-coolant accidents. (author)

40 CFR 721.4663 - Fluorinated carboxylic acid alkali metal salts.

Science.gov (United States)

2010-07-01

... Specific Chemical Substances § 721.4663 Fluorinated carboxylic acid alkali metal salts. (a) Chemical... fluorinated carboxylic acid alkali metal salts (PMNs P-95-979/980/981) are subject to reporting under this... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Fluorinated carboxylic acid alkali...

Structure and electrical resistivity of alkali-alkali and lithium-based liquid binary alloys

International Nuclear Information System (INIS)

Mishra, A.K.; Mukherjee, K.K.

1990-01-01

Harmonic model potential, developed and used for simple metals is applied here to evaluate hardsphere diameters, which ensure minimum interionic pair potential for alkali-alkali (Na-K, Na-Rb, Na-Cs, K-Rb, K-Cs) and lithium-based (Li-Na, Li-Mg, Li-In, Li-Tl) liquid binary alloys as a function of composition for use in the determination of their partial structure factors. These structure factors are then used to calculate electrical resistivities of alloys considered. The computed values of electrical resistivity as a function of composition agree both, in magnitude and gradient reasonably well with experimental values in all cases except in Cs systems, where the disagreement is appreciable. (author)

Radiolysis of cesium iodide solutions at 35 and 85 deg C

International Nuclear Information System (INIS)

Lucas, M.

1981-09-01

An aqueous solution of cesium iodide was irradiated by the gamma rays from a cobalt 60 source with a dose rate of 0.4 Mrad/hr. At 35 deg C the iodide I - is oxidized in molecular iodine I 2 but at 85 deg C the iodate IO 3 - is obtained. The aim of this work is the study of aerosols behaviour released in accidental situation of a PWR in presence of steam [fr

Mineralization dynamics of metakaolin-based alkali-activated cements

Science.gov (United States)

Gevaudan, Juan Pablo; Campbell, Kate M.; Kane, Tyler; Shoemaker, Richard K.; Srubar, Wil V.

2017-01-01

This paper investigates the early-age dynamics of mineral formation in metakaolin-based alkali-activated cements. The effects of silica availability and alkali content on mineral formation were investigated via X-ray diffraction and solid-state 29Si magic-angle spinning nuclear magnetic resonance spectroscopy at 2, 7, 14, and 28 days. Silica availability was controlled by using either liquid- (immediate) or solid-based (gradual) sodium silicate supplements. Mineral (zeolitic) and amorphous microstructural characteristics were correlated with observed changes in bulk physical properties, namely shrinkage, density, and porosity. Results demonstrate that, while alkali content controls the mineralization in immediately available silica systems, alkali content controls the silica availability in gradually available silica systems. Immediate silica availability generally leads to a more favorable mineral formation as demonstrated by correlated improvements in bulk physical properties.

In situ alkali-silica reaction observed by x-ray microscopy

International Nuclear Information System (INIS)

Kurtis, K.E.; Monteiro, P.J.M.; Brown, J.T.; Meyer-Ilse, W.

1997-01-01

In concrete, alkali metal ions and hydroxyl ions contributed by the cement and reactive silicates present in aggregate can participate in a destructive alkali-silica reaction (ASR). This reaction of the alkalis with the silicates produces a gel that tends to imbibe water found in the concrete pores, leading to swelling of the gel and eventual cracking of the affected concrete member. Over 104 cases of alkali-aggregate reaction in dams and spillways have been reported around the world. At present, no method exists to arrest the expansive chemical reaction which generates significant distress in the affected structures. Most existing techniques available for the examination of concrete microstructure, including ASR products, demand that samples be dried and exposed to high pressure during the observation period. These sample preparation requirements present a major disadvantage for the study of alkali-silica reaction. Given the nature of the reaction and the affect of water on its products, it is likely that the removal of water will affect the morphology, creating artifacts in the sample. The purpose of this research is to observe and characterize the alkali-silica reaction, including each of the specific reactions identified previously, in situ without introducing sample artifacts. For observation of unconditioned samples, x-ray microscopy offers an opportunity for such an examination of the alkali-silica reaction. Currently, this investigation is focusing on the effect of calcium ions on the alkali-silica reaction

In situ alkali-silica reaction observed by x-ray microscopy

Energy Technology Data Exchange (ETDEWEB)

Kurtis, K.E.; Monteiro, P.J.M. [Univ. of California, Berkeley, CA (United States); Brown, J.T.; Meyer-Ilse, W. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States)

1997-04-01

In concrete, alkali metal ions and hydroxyl ions contributed by the cement and reactive silicates present in aggregate can participate in a destructive alkali-silica reaction (ASR). This reaction of the alkalis with the silicates produces a gel that tends to imbibe water found in the concrete pores, leading to swelling of the gel and eventual cracking of the affected concrete member. Over 104 cases of alkali-aggregate reaction in dams and spillways have been reported around the world. At present, no method exists to arrest the expansive chemical reaction which generates significant distress in the affected structures. Most existing techniques available for the examination of concrete microstructure, including ASR products, demand that samples be dried and exposed to high pressure during the observation period. These sample preparation requirements present a major disadvantage for the study of alkali-silica reaction. Given the nature of the reaction and the affect of water on its products, it is likely that the removal of water will affect the morphology, creating artifacts in the sample. The purpose of this research is to observe and characterize the alkali-silica reaction, including each of the specific reactions identified previously, in situ without introducing sample artifacts. For observation of unconditioned samples, x-ray microscopy offers an opportunity for such an examination of the alkali-silica reaction. Currently, this investigation is focusing on the effect of calcium ions on the alkali-silica reaction.

Carbamazepine (Tegretol) inhibits in vivo iodide uptake and hormone synthesis in rat thyroid glands

International Nuclear Information System (INIS)

Villa, S.M.; Alexander, N.M.

1987-01-01

Decreased serum concentrations of T3 and T4 occur in patients treated with the anticonvulsant drug carbamazepine (CBZ), but with rare exception, these patients remain euthyroid. The mechanism that accounts for diminished hormone levels is unknown, and our objective was to study the direct effect of CBZ on iodide uptake and hormone synthesis in thyroid glands of CBZ-treated and pair-fed control rats. Chronic ingestion (per os) of CBZ in male rats reduced the four hour thyroid 131I-iodide uptake by approximately 60%. This inhibition occurred after the animals had received sufficient CBZ to attain plasma CBZ concentrations of 0.8 microgram/ml. Continued treatment with CBZ ranging from 560 to 800 mg/kg/day for 14 days did not result in further inhibition of iodide uptake even though the plasma CBZ concentrations had increased 6-20 fold. No inhibition of iodide uptake was apparent when the animals initially received CBZ ranging from 40 to 152 mg/kg body weight for 22 days when there were no detectable levels of plasma CBZ. Overall growth rates of CBZ-treated rats were slightly (6-10%) less than the pair-fed control animals. Plasma T4 concentrations were reduced by 18% (p less than 0.05) in the CBZ-fed animals, while T3 concentrations were diminished by 53% (p less than 0.01). CBZ appeared to alter thyroidal iodide transport because the thyroid:plasma iodide ratios were decreased by 26% in the drug-treated rats. The distribution of radioiodine in thyroidal iodoamino acids was essentially the same in both groups of rats but the absolute quantities of radioiodine were more than 2.5 times greater in the control rats. CBZ failed to inhibit peroxidase-catalyzed iodide and guaiacol oxidation in vitro

One column method to prepare 11C-labelled methyl iodide

International Nuclear Information System (INIS)

Kovacs, Z.; Priboczki, E.

1999-01-01

A new method in which the [ 11 C]methyl iodide is prepared on one alumina column is presented. A high specific surface alumina column, previously impregnated with lithium aluminium hydride solution, was used for direct trapping from the target gas and reduction into radiocomplex. The complex was then reacted on this column with HI to form [ 11 C]methyl iodide. The use of one alumina column, instead of a freezing trap, reaction vessel and separate unit for iodination, simplifies the apparatus, shortens the synthesis time and is well suitable for automation. (K.A.)

Iodide-trapping defect of the thyroid

International Nuclear Information System (INIS)

Pannall, P.R.; Steyn, A.F.; Van Reenen, O.

1978-01-01

We describe a grossly hypothyroid 50-year-old woman, mentally retarded since birth. On the basis of her history of recurrent goitre, absence of 131 I neck uptake and a low saliva/plasma 131 I ratio, congenital hypothyroidism due to a defect of the iodide-trapping mechanism was diagnosed. Other family members studied did not have the defect

Alkali (Li, K and Na) and alkali-earth (Be, Ca and Mg) adatoms on SiC single layer

Science.gov (United States)

Baierle, Rogério J.; Rupp, Caroline J.; Anversa, Jonas

2018-03-01

First-principles calculations within the density functional theory (DFT) have been addressed to study the energetic stability, and electronic properties of alkali and alkali-earth atoms adsorbed on a silicon carbide (SiC) single layer. We observe that all atoms are most stable (higher binding energy) on the top of a Si atom, which moves out of the plane (in the opposite direction to the adsorbed atom). Alkali atoms adsorbed give raise to two spin unpaired electronic levels inside the band gap leading the SiC single layer to exhibit n-type semiconductor properties. For alkaline atoms adsorbed there is a deep occupied spin paired electronic level inside the band gap. These finding suggest that the adsorption of alkaline and alkali-earth atoms on SiC layer is a powerful feature to functionalize two dimensional SiC structures, which can be used to produce new electronic, magnetic and optical devices as well for hydrogen and oxygen evolution reaction (HER and OER, respectively). Furthermore, we observe that the adsorption of H2 is ruled by dispersive forces (van der Waals interactions) while the O2 molecule is strongly adsorbed on the functionalized system.

Electrosorption of tetraalkylammonium ions on silver iodide

NARCIS (Netherlands)

Keizer, de A.

1981-01-01

The object of the present investigations was to study the ef fect of the adsorption of charged organic ions on electrically charged, solid-liquid interfaces. To that end, symmetrical quater nary ammonium ions were adsorbed on a silver iodide-electrolyte interface at various

21 CFR 520.763b - Dithiazanine iodide powder.

Science.gov (United States)

2010-04-01

... therapy for adult worms. (2) The drug is contraindicated in animals sensitive to dithiazanine iodide and...) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS ORAL DOSAGE FORM NEW ANIMAL DRUGS § 520.763b Dithiazanine...

[Identification and function test of an alkali-tolerant denitrifying bacterium].

Science.gov (United States)

Wang, Ru; Zheng, Ping; Li, Wei; Chen, Hui; Chen, Tingting; Ghulam, Abbas

2013-04-04

We obtained an alkali-tolerant denitrifying bacterium, and determined its denitrifying activity and alkali-tolerance. An alkali-tolerant denitrifying bacterial strain was obtained by isolation and purification. We identified the bacterial strain by morphological observation, physiological test and 16S rRNA analysis. We determined the denitrifying activity and alkali-tolerance by effects of initial nitrate concentration and initial pH on denitrification. An alkali-tolerant denitrifier strain R9 was isolated from the lab-scale high-rate denitrifying reactor, and it was identified as Diaphorobater nitroreducens. The strain R9 grew heterotrophically with methanol as the electron donor and nitrate as the electron acceptor. The nitrate conversion was 93.25% when strain R9 was cultivated for 288 h with initial nitrate concentration 50 mg/L and initial pH 9.0. The denitrification activity could be inhibited at high nitrate concentration with a half inhibition constant of 202.73 mg N/L. Strain R9 showed a good alkali tolerance with the nitrate removal rate at pH 11.0 remained 86% of that at pH 9.0. Strain R9 was identified as Diaphorobater nitroreducens, and it was an alkali-tolerant denitrifying bacterium with optimum pH value of 9.0.

Maternal exposure to alkali, alkali earth, transition and other metals: Concentrations and predictors of exposure

International Nuclear Information System (INIS)

Hinwood, A.L.; Stasinska, A.; Callan, A.C.; Heyworth, J.; Ramalingam, M.; Boyce, M.; McCafferty, P.; Odland, J.Ø.

2015-01-01

Most studies of metals exposure focus on the heavy metals. There are many other metals (the transition, alkali and alkaline earth metals in particular) in common use in electronics, defense industries, emitted via combustion and which are naturally present in the environment, that have received limited attention in terms of human exposure. We analysed samples of whole blood (172), urine (173) and drinking water (172) for antimony, beryllium, bismuth, cesium, gallium, rubidium, silver, strontium, thallium, thorium and vanadium using ICPMS. In general most metals concentrations were low and below the analytical limit of detection with some high concentrations observed. Few factors examined in regression models were shown to influence biological metals concentrations and explained little of the variation. Further study is required to establish the source of metals exposures at the high end of the ranges of concentrations measured and the potential for any adverse health impacts in children. - This study has demonstrated exposure to alkali, alkali earth and transition metals in pregnant women with factors such as breastfeeding, fish oil use and diet affecting exposures

Electrochemistry of silver iodide the capacity of the double layer at the silver iodide-water interface

NARCIS (Netherlands)

Lyklema, J.; Overbeek, J.Th.G.

1961-01-01

A method is described for obtaining differential double layer capacities on silver iodide. Especially the influence of the nature and concentration of indifferent electrolytes was investigated, viz., the nitrates of Li·, K·, Rb·, NH4·, H·, Tl·, Mg··, Ba··, Co··, Cd··, Pb··, La···, Th····, the

Alkali content of fly ash : measuring and testing strategies for compliance.

Science.gov (United States)

2015-04-01

Sodium and potassium are the common alkalis present in fly ash. Excessive amounts of fly ash alkalis can cause efflorescence : problems in concrete products and raise concern about the effectiveness of the fly ash to mitigate alkali-silica reaction (...

Electronic and optical properties of lead iodide

DEFF Research Database (Denmark)

Ahuja, R.; Arwin, H.; Ferreira da Silva, A.

2002-01-01

The electronic properties and the optical absorption of lead iodide (PbI2) have been investigated experimentally by means of optical absorption and spectroscopic ellipsometry, and theoretically by a full-potential linear muffin-tin-orbital method. PbI2 has been recognized as a very promising...

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.

Electronic and atomic structures of liquid tellurium containing alkali elements

International Nuclear Information System (INIS)

Kawakita, Yukinobu; Yao, Makoto; Endo, Hirohisa.

1997-01-01

The measurements of electrical conductivity σ, density, EXAFS and neutron scattering were carried out for liquid K-Te and Rb-Te mixtures. The conductivity σ decreases rapidly with alkali concentration and a metal-semiconductor transition occurs at about 10 at.% alkali. It is found that the compositional variation of σ is nearly independent of the alkali species. The Te-Te bond length deduced from EXAFS and neutron scattering measurements is 2.8 A and changes little with alkali concentrations. The average distances from K and Rb atom to Te atoms are 3.6 A and 3.8 A, respectively. Two kinds of relaxation processes are observed in quasielastic neutron scattering for K 20 Te 80 . Upon the addition of alkali the interaction between the neighbouring Te chains, which is responsible for the metallic conduction, weaken considerably. (author)

An iodine supplementation of tomato fruits coated with an edible film of the iodide-doped chitosan.

Science.gov (United States)

Limchoowong, Nunticha; Sricharoen, Phitchan; Techawongstien, Suchila; Chanthai, Saksit

2016-06-01

In general, the risk of numerous thyroid cancers inevitably increases among people with iodine deficiencies. An iodide-doped chitosan (CT-I) solution was prepared for dipping tomatoes to coat the fresh surface with an edible film (1.5 μm), thereby providing iodine-rich fruits for daily intake. Characterisation of the thin film was conducted by FTIR and SEM. Stability of the CT-I film was studied via water immersion at various time intervals, and no residual iodide leached out due to intrinsic interactions between the cationic amino group of chitosan and iodide ions. Moreover, the iodide supplement exhibited no effect on the antioxidant activity of tomatoes. The iodine content in the film-coated tomato was determined by ICP-OES. The tomato coating with 1.5% (w/v) CT-I contained approximately 0.4 μg iodide per gram fresh weight. In addition, the freshness and storability of iodine-doped tomatoes were also maintained for shelf-life concerns. Copyright © 2016 Elsevier Ltd. All rights reserved.

Survival probability in small angle scattering of low energy alkali ions from alkali covered metal surfaces

International Nuclear Information System (INIS)

Neskovic, N.; Ciric, D.; Perovic, B.

1982-01-01

The survival probability in small angle scattering of low energy alkali ions from alkali covered metal surfaces is considered. The model is based on the momentum approximation. The projectiles are K + ions and the target is the (001)Ni+K surface. The incident energy is 100 eV and the incident angle 5 0 . The interaction potential of the projectile and the target consists of the Born-Mayer, the dipole and the image charge potentials. The transition probability function corresponds to the resonant electron transition to the 4s projectile energy level. (orig.)

Reaction of alkali nitrates with PuO2

International Nuclear Information System (INIS)

Yamashita, T.; Ohuchi, K.; Takahashi, K.; Fujino, T.

1990-01-01

Improvement of solubility of plutonium dioxide (PuO 2 ) in acid solution is important to establish the nuclear fuel reprocessing technique for uranium-plutonium mixed oxide fuels. If insoluble PuO 2 can be converted into any soluble plutonium compounds, problems arising from the fuel dissolution process will be reduced to a great extent. Alkali metal plutonates and alkaline-earth plutonates are known to have enhanced solubility in mineral acids. However, the reaction conditions to form such plutonates and characterization thereof are not well elucidated. Then the reactivity and reaction conditions to form lithium and sodium plutonates from their nitrates and PuO 2 were studied at temperatures between 500 and 900 degree C and alkali metal to plutonium atom ratios between 0.5 and 6 by means of thermogravimetry as well as X-ray diffraction technique. The reaction behavior of alkali plutonates will be discussed in comparison with corresponding alkali uranates

Transcriptome alteration in a rice introgression line with enhanced alkali tolerance.

Science.gov (United States)

Zhang, Yunhong; Lin, Xiuyun; Ou, Xiufang; Hu, Lanjuan; Wang, Jinming; Yang, Chunwu; Wang, Shucai; Liu, Bao

2013-07-01

Alkali stress inhibits plant growth and development and thus limits crop productivity. To investigate the possible genetic basis of alkali tolerance in rice, we generated an introgressed rice line (K83) with significantly enhanced tolerance to alkali stress compared to its recipient parental cultivar (Jijing88). By using microarray analysis, we examined the global gene expression profiles of K83 and Jijing88, and found that more than 1200 genes were constitutively and differentially expressed in K83 in comparison to Jijing88 with 572 genes up- and 654 down-regulated. Upon alkali treatment, a total of 347 genes were found up- and 156 down-regulated in K83 compared to 591 and 187, respectively, in Jijing88. Among the up-regulated genes in both K83 and Jijing88, only 34 were constitutively up-regulated in K83, suggesting that both the constitutive differentially expressed genes in K83 and those induced by alkali treatment are most likely responsible for enhanced alkali tolerance. A gene ontology analysis based on all annotated, differentially expressed genes revealed that genes with expression alterations were enriched in pathways involved in metabolic processes, catalytic activity, and transport and transcription factor activities, suggesting that these pathways are associated with alkali stress tolerance in rice. Our results illuminated the novel genetic aspects of alkali tolerance in rice and established a repertory of potential target genes for biotechnological manipulations that can be used to generate alkali-tolerant rice cultivars. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

The alkali-aggregate reaction - concrete microstructure evolution

International Nuclear Information System (INIS)

Regourd, M.; Hornain, H.; Poitevin, P.

1981-01-01

The alkali-aggregate reaction has been studied by scanning electron microscopy and energy dispersive X-ray analysis, electron probe microanalysis, and X-ray diffraction in concretes containing glass aggregates or hornfels and greywacke aggregates. The surface reaction of the natural aggregates in alkaline solutions has been analysed by X-ray photo-electron spectrometry. The study of concretes with glass aggregates stored at 20 degrees Celcius and 100 percent relative humidity has revealed, irrespective of alkali content and type of cement, the formation of a gel containing SiO 2 , Na 2 O, CaO, MgO and Al 2 O 3 . Under heat and pressure (210 degrees Celcius at MPa for 48 hours), the gel crystallizes and yields silicates not very different from tobermorite found in autoclaved normal concretes but cotaining Na and K in solid solutions. The alkali reaction in two natural aggregate concretes, is also shown by the formation of gels and silicate crystals. The progressive structuring of the gels in silicate crystals is promoted by an increase in temperature. Ettringite and Ca(OH) 2 reinforce the alkali-aggregate reaction which may be looked upon as a hydration reaction, partially of the pozzolanic type

Capture of organic iodides from nuclear waste by metal-organic framework-based molecular traps.

Science.gov (United States)

Li, Baiyan; Dong, Xinglong; Wang, Hao; Ma, Dingxuan; Tan, Kui; Jensen, Stephanie; Deibert, Benjamin J; Butler, Joseph; Cure, Jeremy; Shi, Zhan; Thonhauser, Timo; Chabal, Yves J; Han, Yu; Li, Jing

2017-09-07

Effective capture of radioactive organic iodides from nuclear waste remains a significant challenge due to the drawbacks of current adsorbents such as low uptake capacity, high cost, and non-recyclability. We report here a general approach to overcome this challenge by creating radioactive organic iodide molecular traps through functionalization of metal-organic framework materials with tertiary amine-binding sites. The molecular trap exhibits a high CH 3 I saturation uptake capacity of 71 wt% at 150 °C, which is more than 340% higher than the industrial adsorbent Ag 0 @MOR under identical conditions. These functionalized metal-organic frameworks also serve as good adsorbents at low temperatures. Furthermore, the resulting adsorbent can be recycled multiple times without loss of capacity, making recyclability a reality. In combination with its chemical and thermal stability, high capture efficiency and low cost, the adsorbent demonstrates promise for industrial radioactive organic iodides capture from nuclear waste. The capture mechanism was investigated by experimental and theoretical methods.Capturing radioactive organic iodides from nuclear waste is important for safe nuclear energy usage, but remains a significant challenge. Here, Li and co-workers fabricate a stable metal-organic framework functionalized with tertiary amine groups that exhibits high capacities for radioactive organic iodides uptake.

Capture of organic iodides from nuclear waste by metal-organic framework-based molecular traps

KAUST Repository

Li, Baiyan

2017-09-01

Effective capture of radioactive organic iodides from nuclear waste remains a significant challenge due to the drawbacks of current adsorbents such as low uptake capacity, high cost, and non-recyclability. We report here a general approach to overcome this challenge by creating radioactive organic iodide molecular traps through functionalization of metal-organic framework materials with tertiary amine-binding sites. The molecular trap exhibits a high CH3I saturation uptake capacity of 71 wt% at 150 °C, which is more than 340% higher than the industrial adsorbent Ag0@MOR under identical conditions. These functionalized metal-organic frameworks also serve as good adsorbents at low temperatures. Furthermore, the resulting adsorbent can be recycled multiple times without loss of capacity, making recyclability a reality. In combination with its chemical and thermal stability, high capture efficiency and low cost, the adsorbent demonstrates promise for industrial radioactive organic iodides capture from nuclear waste. The capture mechanism was investigated by experimental and theoretical methods.Capturing radioactive organic iodides from nuclear waste is important for safe nuclear energy usage, but remains a significant challenge. Here, Li and co-workers fabricate a stable metal-organic framework functionalized with tertiary amine groups that exhibits high capacities for radioactive organic iodides uptake.

Contrasting the surface ocean distribution of bromoform and methyl iodide; implications for boundary layer physics, chemistry and climate

Energy Technology Data Exchange (ETDEWEB)

Palmer, C J, E-mail: carl.j.palmer@gmail.co [Department of Oceanography, University of Cape Town, 7701 (South Africa)

2010-08-15

Bromoform and methyl iodide are both methane-like hydrocarbons with a halogen atom replacing one or more of the hydrogen atoms. Both of these compounds occur naturally in the environment as a result of their production from seaweed and kelp. They are of interest to climate science as a result of their catalytic destruction of boundary layer ozone (a potent greenhouse gas) and, specifically for methyl iodide, the proposed role in the formation of new cloud condensation nuclei with implications for climate. In this paper, the currently available data on the distribution of bromoform and methyl iodide are analysed and contrasted to show that the concentrations of bromoform and methyl iodide do not correlate, that, in contrast to bromoform, the parameterization of sea surface methyl iodide concentrations demands only the sea surface temperature, and that the pelagic distribution of methyl iodide appears to follow the solar zenith angle. These three observations together suggest that, while the pelagic source of bromoform is mostly biogenic, the source of methyl iodide is photochemical. This has implications for the understanding of planetary boundary layer chemistry and potential organohalogen mediated feedbacks to climate.

Contrasting the surface ocean distribution of bromoform and methyl iodide; implications for boundary layer physics, chemistry and climate

International Nuclear Information System (INIS)

Palmer, C J

2010-01-01

Bromoform and methyl iodide are both methane-like hydrocarbons with a halogen atom replacing one or more of the hydrogen atoms. Both of these compounds occur naturally in the environment as a result of their production from seaweed and kelp. They are of interest to climate science as a result of their catalytic destruction of boundary layer ozone (a potent greenhouse gas) and, specifically for methyl iodide, the proposed role in the formation of new cloud condensation nuclei with implications for climate. In this paper, the currently available data on the distribution of bromoform and methyl iodide are analysed and contrasted to show that the concentrations of bromoform and methyl iodide do not correlate, that, in contrast to bromoform, the parameterization of sea surface methyl iodide concentrations demands only the sea surface temperature, and that the pelagic distribution of methyl iodide appears to follow the solar zenith angle. These three observations together suggest that, while the pelagic source of bromoform is mostly biogenic, the source of methyl iodide is photochemical. This has implications for the understanding of planetary boundary layer chemistry and potential organohalogen mediated feedbacks to climate.

Simultaneous detection of iodine and iodide on boron doped diamond electrodes.

Science.gov (United States)

Fierro, Stéphane; Comninellis, Christos; Einaga, Yasuaki

2013-01-15

Individual and simultaneous electrochemical detection of iodide and iodine has been performed via cyclic voltammetry on boron doped diamond (BDD) electrodes in a 1M NaClO(4) (pH 8) solution, representative of typical environmental water conditions. It is feasible to compute accurate calibration curve for both compounds using cyclic voltammetry measurements by determining the peak current intensities as a function of the concentration. A lower detection limit of about 20 μM was obtained for iodide and 10 μM for iodine. Based on the comparison between the peak current intensities reported during the oxidation of KI, it is probable that iodide (I(-)) is first oxidized in a single step to yield iodine (I(2)). The latter is further oxidized to obtain IO(3)(-). This technique, however, did not allow for a reasonably accurate detection of iodate (IO(3)(-)) on a BDD electrode. Copyright © 2012 Elsevier B.V. All rights reserved.

Comparative study of diode-pumped alkali vapor laser and exciplex-pumped alkali laser systems and selection principal of parameters

Science.gov (United States)

Huang, Wei; Tan, Rongqing; Li, Zhiyong; Han, Gaoce; Li, Hui

2017-03-01

A theoretical model based on common pump structure is proposed to analyze the output characteristics of a diode-pumped alkali vapor laser (DPAL) and XPAL (exciplex-pumped alkali laser). Cs-DPAL and Cs-Ar XPAL systems are used as examples. The model predicts that an optical-to-optical efficiency approaching 80% can be achieved for continuous-wave four- and five-level XPAL systems with broadband pumping, which is several times the pumped linewidth for DPAL. Operation parameters including pumped intensity, temperature, cell's length, mixed gas concentration, pumped linewidth, and output coupler are analyzed for DPAL and XPAL systems based on the kinetic model. In addition, the predictions of selection principal of temperature and cell's length are also presented. The concept of the equivalent "alkali areal density" is proposed. The result shows that the output characteristics with the same alkali areal density but different temperatures turn out to be equal for either the DPAL or the XPAL system. It is the areal density that reflects the potential of DPAL or XPAL systems directly. A more detailed analysis of similar influences of cavity parameters with the same areal density is also presented.

40 CFR 721.10098 - Disubstituted benzoic acid, alkali metal salt (generic).

Science.gov (United States)

2010-07-01

... New Uses for Specific Chemical Substances § 721.10098 Disubstituted benzoic acid, alkali metal salt... identified generically as disubstituted benzoic acid, alkali metal salt (PMN P-03-643) is subject to... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Disubstituted benzoic acid, alkali...

Alkali solution extraction of rice residue protein isolates: Influence of alkali concentration on protein functional, structural properties and lysinoalanine formation.

Science.gov (United States)

Hou, Furong; Ding, Wenhui; Qu, Wenjuan; Oladejo, Ayobami Olayemi; Xiong, Feng; Zhang, Weiwei; He, Ronghai; Ma, Haile

2017-03-01

This study evaluated the nutrient property and safety of the rice residue protein isolates (RRPI) product (extracted by different alkali concentrations) by exploring the protein functional, structural properties and lysinoalanine (LAL) formation. The results showed that with the rising of alkali concentration from 0.03M to 0.15M, the solubility, emulsifying and foaming properties of RRPI increased at first and then descended. When the alkali concentration was greater than 0.03M, the RRPI surface hydrophobicity decreased and the content of thiol and disulfide bond, Lys and Cys significantly reduced. By the analysis of HPLC, the content of LAL rose up from 276.08 to 15,198.07mg/kg and decreased to 1340.98mg/kg crude protein when the alkali concentration increased from 0.03 to 0.09M and until to 0.15M. These results indicated that RRPI alkaline extraction concentration above 0.03M may cause severe nutrient or safety problems of protein. Copyright © 2016 Elsevier Ltd. All rights reserved.

Alkali-Activated Natural Pozzolan/Slag Binder for Sustainable Concrete

Science.gov (United States)

Najimi, Meysam

This study aimed to fully replace Portland cement (PC) with environmentally friendly binders capable of improving longevity of concrete. The new binders consisted of different proportions of natural Pozzolan and slag which were alkaline-activated with various combinations of sodium hydroxide and sodium silicate. A step-by-step research program was designed to (1) develop alkali-activated natural Pozzolan/slag pastes with adequate fresh and strength properties, (2) produce alkali-activated natural Pozzolan/slag mortars to assess the effects of dominant variables on their plastic and hardened properties, and (3) finally produce and assess fresh, mechanical, dimensional, transport and durability properties of alkali-activated natural Pozzolan/slag concretes. The major variables included in this study were binder combination (natural Pozzolan/slag combinations of 70/30, 50/50 and 30/70), activator combination (sodium silicate/sodium hydroxide combinations of 20/80, 25/75 and 30/70), and sodium hydroxide concentration (1, 1.75 and 2.5M). The experimental program assessed performance of alkali-activated natural Pozzolan/slag mixtures including fresh properties (flow and setting times), unit weights (fresh, demolded and oven-dry), mechanical properties (compressive and tensile strengths, and modulus of elasticity), transport properties (absorption, rapid chloride penetration, and rapid chloride migration), durability (frost resistance, chloride induced corrosion, and resistance to sulfuric acid attack), and dimensional stability (drying shrinkage). This study also compared the performance of alkali-activated natural Pozzolan/slag concretes with that of an equivalent reference Portland cement concrete having a similar flow and strength characteristics. The results of this study revealed that it was doable to find optimum binder proportions, activator combinations and sodium hydroxide concentrations to achieve adequate plastic and hardened properties. Nearly for all studied

Determination of the common and rare alkalies in mineral analysis

Science.gov (United States)

Wells, R.C.; Stevens, R.E.

1934-01-01

Methods are described which afford a determination of each member of the alkali group and are successful in dealing with the quantities of the rare alkalies found in rocks and minerals. The procedures are relatively rapid and based chiefly on the use of chloroplatinic acid, absolute alcohol and ether, and ammonium sulfate. The percentages of all the alkalies found in a number of minerals are given.

40 CFR 721.5452 - Alkali metal salt of halogenated organoborate (generic).

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkali metal salt of halogenated... Specific Chemical Substances § 721.5452 Alkali metal salt of halogenated organoborate (generic). (a... generically as alkali metal salt of halogenated organoborate (PMN P-00-0638) is subject to reporting under...

Physiological Evaluation of Alkali-Salt Tolerance of Thirty Switchgrass (Panicum virgatum Lines.

Directory of Open Access Journals (Sweden)

Guofu Hu

Full Text Available Soil salt-alkalization is a major limiting factor for crop production in many regions. Switchgrass (Panicum virgatum L. is a warm-season C4 perennial rhizomatous bunchgrass and a target lignocellulosic biofuel species. The objective of this study was to evaluate relative alkali-salt tolerance among 30 switchgrass lines. Tillers of each switchgrass line were transplanted into pots filled with fine sand. Two months after transplanting, plants at E5 developmental stage were grown in either half strength Hoagland's nutrient solution with 0 mM Na+ (control or half strength Hoagland's nutrient solution with 150 mM Na+ and pH of 9.5 (alkali-salt stress treatment for 20 d. Alkali-salt stress damaged cell membranes [higher electrolyte leakage (EL], reduced leaf relative water content (RWC, net photosynthetic rate (Pn, stomatal conductance (gs, and transpiration rate (Tr. An alkali-salt stress tolerance trait index (ASTTI for each parameter was calculated based on the ratio of the value under alkali-salt stress and the value under non-stress conditions for each parameter of each line. Relative alkali-salt tolerance was determined based on principal components analysis and cluster analysis of the physiological parameters and their ASTTI values. Significant differences in alkali-salt stress tolerance were found among the 30 lines. Lowland lines TEM-SEC, Alamo, TEM-SLC and Kanlow were classified as alkali-salt tolerant. In contrast, three lowland lines (AM-314/MS-155, BN-13645-64 and two upland lines (Caddo and Blackwell-1 were classified as alkali-salt sensitive. The results suggest wide variations exist in alkali-salt stress tolerance among the 30 switchgrass lines. The approach of using a combination of principal components and cluster analysis of the physiological parameters and related ASTTI is feasible for evaluating alkali-salt tolerance in switchgrass.

Physiological Evaluation of Alkali-Salt Tolerance of Thirty Switchgrass (Panicum virgatum) Lines.

Science.gov (United States)

Hu, Guofu; Liu, Yiming; Zhang, Xunzhong; Yao, Fengjiao; Huang, Yan; Ervin, Erik H; Zhao, Bingyu

2015-01-01

Soil salt-alkalization is a major limiting factor for crop production in many regions. Switchgrass (Panicum virgatum L.) is a warm-season C4 perennial rhizomatous bunchgrass and a target lignocellulosic biofuel species. The objective of this study was to evaluate relative alkali-salt tolerance among 30 switchgrass lines. Tillers of each switchgrass line were transplanted into pots filled with fine sand. Two months after transplanting, plants at E5 developmental stage were grown in either half strength Hoagland's nutrient solution with 0 mM Na+ (control) or half strength Hoagland's nutrient solution with 150 mM Na+ and pH of 9.5 (alkali-salt stress treatment) for 20 d. Alkali-salt stress damaged cell membranes [higher electrolyte leakage (EL)], reduced leaf relative water content (RWC), net photosynthetic rate (Pn), stomatal conductance (gs), and transpiration rate (Tr). An alkali-salt stress tolerance trait index (ASTTI) for each parameter was calculated based on the ratio of the value under alkali-salt stress and the value under non-stress conditions for each parameter of each line. Relative alkali-salt tolerance was determined based on principal components analysis and cluster analysis of the physiological parameters and their ASTTI values. Significant differences in alkali-salt stress tolerance were found among the 30 lines. Lowland lines TEM-SEC, Alamo, TEM-SLC and Kanlow were classified as alkali-salt tolerant. In contrast, three lowland lines (AM-314/MS-155, BN-13645-64) and two upland lines (Caddo and Blackwell-1) were classified as alkali-salt sensitive. The results suggest wide variations exist in alkali-salt stress tolerance among the 30 switchgrass lines. The approach of using a combination of principal components and cluster analysis of the physiological parameters and related ASTTI is feasible for evaluating alkali-salt tolerance in switchgrass.

Interactions of nucleobases with alkali earth metal cations--electrospray ionization mass spectrometric study.

Science.gov (United States)

Frańska, Magdalena

2007-01-01

Interactions of nucleobases with alkali earth metal cations have been studied by electrospray ionization mass spectrometry (ESI-MS). Nucleobases containing at least one oxygen atom form stable complexes with alkali earth metal cations. This phenomenon can be explained on the grounds of the well known theory of hard and soft acids and bases. Uracil and thymine make complexes only when in their deprotonoted forms. The cations of great radii (Sr(2+), Ba(2+)) are more prone to form complexes of stoichiometry 1:1 with uracil and thymine than the cations of small radii (Mg(2+), Ca(2+)). On the other hand, Mg(2+) forms complexes of stoichiometry 2:1 and 3:2 with uracil and thymine. Gas-phase stabilities of the 1:1 complexes are higher for the cations of small radii, in contrast to the solution stabilities. For cytosine and 9- methylhypoxantine the 1:1 complexes of their deprotonated forms are observed at higher cone voltage as a result of HCl molecule loss from the complexes containing the counter ion (Cl(-)). In solution, more stable complexes are formed with metal cations of low radii. Gas-phase stability of the complexes formed by deprotonated 9- methyl-hypoxantine increases with increasing metal cation radius.

Solvent effect on the rate and equilibrium of reaction between 10-phenylphenoxarsine and methyl iodide

International Nuclear Information System (INIS)

Gavrilov, V.I.; Gumerov, N.S.; Rakhmatullin, R.R.

1990-01-01

Effect of solvent nature on nucleophilic capacity of three-coordinated arsenic and the equilibrium state of 10-phenylphenoxarsine (PA) reaction with methyl iodide are studied. Kinetic investigations are carried out by the conductometry at 24,35,45 deg C. It is established that quaternization of PA with methyl iodide when substituting a solvent (ketone for alcohol) increases 3-14 times with simultaneous growth of the activation energy value. When transforming from aprotic solvents to protic ones PA interaction equilibrium with methyl iodide shifts to the side of arsonic salt formation

40 CFR 721.5985 - Fatty alkyl phosphate, alkali metal salt (generic).

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Fatty alkyl phosphate, alkali metal... Specific Chemical Substances § 721.5985 Fatty alkyl phosphate, alkali metal salt (generic). (a) Chemical... as a fatty alkyl phosphate, alkali metal salt (PMN P-99-0385) is subject to reporting under this...

40 CFR 721.4660 - Alcohol, alkali metal salt.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alcohol, alkali metal salt. 721.4660 Section 721.4660 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.4660 Alcohol, alkali metal sal...

Identification of Phase Composition of Binders from Alkali-Activated Mixtures of Granulated Blast Furnace Slag and Fly Ash

Czech Academy of Sciences Publication Activity Database

Vlček, J.; Drongová, L.; Topinková, M.; Matějka, V.; Kukutschová, J.; Vavro, Martin; Tomková, V.

2014-01-01

Roč. 58, č. 1 (2014), s. 79-88 ISSN 0862-5468 Institutional support: RVO:68145535 Keywords : binders * alkali activation * hydration products Subject RIV: JM - Building Engineering Impact factor: 0.435, year: 2014 http://www.ceramics-silikaty.cz/2014/pdf/2014_01_079.pdf

Synthesis and evaluation of iodide uptake inhibitors in thyroid gland

International Nuclear Information System (INIS)

Lacotte, Pierre

2012-01-01

This work was intended to discover small organic molecules acting as iodide uptake inhibitors in thyroid cells. These compounds can indeed be derivatized into biochemical probes for further characterization of proteins involved in iodide transport mechanisms. On the long term, these inhibitors also appear as attractive drug candidates for treatment of thyroid pathologies or radioprotection against iodine isotopes. A similar strategy was adopted for both of the two inhibitor families. First, we synthesized a chemical library of around 100 analogues; we measured their IC50 against iodide uptake in FRTL-5 cells to get structure-activity relationships. Absolute configuration of stereo-genic centers was also investigated, and a preferential stereochemistry was found to be responsible for activity. From this basis, around twenty 'second-generation' analogues were synthesized by combining fragments contributing to biological activity. Biological evaluation indicated that nine were very potent inhibitors, with IC50 ≤ 6 nM and satisfying physicochemical properties required for drug candidates. Finally, one photoactivatable biotinylated probe was developed in each family and used for photoaffinity labeling. Several specifically labeled proteins are still under identification and constitute new potential therapeutic targets. (author)

The method of determination of micro quantities of labelled iodide in Na125 I carrier free solution

International Nuclear Information System (INIS)

Kholbaev, A.Kh.; Shilin, E.A.

1996-01-01

The analytical method was elaborated with the purpose to increase detection limit and radiation safety of labelled iodide determination. The method includes oxidation of iodide by iodate in diluted sulphur acid solution with molar concentration 0,03-0,04/moles/litre at molar ratio of iodide to iodate I - :IO - 3 1:12,5. The extraction of I 2 produced is done by toluene. (author)

Autoclave-hardening slag-alkali binder with high water content

International Nuclear Information System (INIS)

Korenevskij, V.V.; Kozyrin, N.A.; Melikhova, N.I.; Narkevich, N.K.; Ryabov, G.G.

1987-01-01

The results of investigations into properties of slag-alkali binder, that may be used for concretes of reactor radiation and thermal shieldings, are presented. These concretes have increased chemical stability and mechanical strength, high content of chemically bound water (approximately 14%), that is not lost under heating up to 550 deg C. Dumping and granulated slags of blast-furnace process, sodium-bicarbonate-alkali fusion cake formed at burning of adipic acid residues, technical sodium hydroxide and sodium liquid glass are used as raw material for slag-alkali binder

Study on the Electrochemical Behavior of Iodide at Platinum Electrode in Potassium Chlorate Solution

Energy Technology Data Exchange (ETDEWEB)

Jung, Sang Hyuk; Yeon, Jei Won; Song, Kyu Seok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2012-05-15

Radioactive iodine-131, is one of the most hazardous fission products which could be released from fuels of nuclear reactors during the severe accident of nuclear power plants. Due to its high radioactivity, high fission yield (2.8%) and hazardous biological effects, the behavior of iodine has been taken interests in many research groups. Iodine is known to be released from the fuels as a cesium iodide form, CsI. And, as nuclear fuels are mostly placed in the water pool, it is easily dissolved in the water after released from the fuels. In water, iodide anion could be oxidized into molecular iodine. As the molecular iodine is a volatile species and the oxidizing rate is affected by many environmental facts such as pH, radiolysis products and temperature, the oxidation reaction of the iodide ion has been considered as an important chemical reaction related to the severe accident of nuclear power plants In present work, the electrochemical behavior of iodide anion was observed by using cyclic voltammetric technique in potassium chlorate solutions. We observed two different oxidation waves in the oxidation potential region. From the comparison with the previous reported results, one is regarded as the oxidation of iodide into molecular iodine. The other is evaluated to be the formation of high-valent iodine-containing compounds

A portable multi-syringe flow system for spectrofluorimetric determination of iodide in seawater.

Science.gov (United States)

Frizzarin, Rejane M; Aguado, Enrique; Portugal, Lindomar A; Moreno, Daniel; Estela, José M; Rocha, Fábio R P; Cerdà, Victor

2015-11-01

A miniaturized analyzer encompassing a poly(methyl methacrylate) chip with integrated spectrofluorimetric detection and solutions propelling by a multi-syringe module is proposed. Iodide was determined through its catalytic effect on the reaction between Ce(IV) and As(III). Matrix isopotential synchronous fluorescence was explored to set the excitation and emission wavelengths. A two-level full factorial design allowed to evaluate the significance of variables (Ce(IV), As(III) and H2SO4 concentrations) and their interaction effects in the experimental domain. A Doehlert Matrix was applied to identify the critical values. The optimized procedure showed a linear response from 1 to 100 μg L(-1) (S=53.7+2.61C, in which S is the net fluorescence and C is iodide concentration in μg L(-1)). Detection limit, coefficient of variation (n=6) and sampling rate were estimated at 0.3 μg L(-1), 0.8% and 20 h(-1), respectively. Recoveries within 90-117% were estimated for iodide spiked to seawater samples. The proposed procedure stands out because of the portability, robustness, and simplicity for in-field analysis of iodide in seawater. Copyright © 2015 Elsevier B.V. All rights reserved.

ALKALI-ACTIVATION KINETICS OF PHOSPHORUS SLAG CEMENT USING COMPRESSIVE STRENGTH DATA

Directory of Open Access Journals (Sweden)

Hojjatollah Maghsoodloorad

2015-09-01

Full Text Available In this research, through compressive strength data, the order and kinetics of alkali-activation of phosphorus slag activated with two compound activators of NaOH + Na2CO3 and Na2CO3 + Ca(OH2, has been evaluated. The kinetics and order of alkali activation is a key factor to forecasting the mechanical behavior of alkali activated cement at different curing time and temperatures without carrying out experimental tests. The apparent activation energy was obtained as 35.6 kJ.mol-1 and 60.7 kJ.mol-1 for the two activators, respectively. Investigations proved that the alkali-activation kinetics of phosphorus slag resembles chemical reactions of second order. Moreover, the order of alkali-activation of phosphorus slag does not depend on the type of activator.

Effect of iodide on glucose oxidation and 32P incorporation into phospholipids stimulated by different agents in dog thyroid slices

International Nuclear Information System (INIS)

Tseng, F.Y.; Rani, C.S.; Field, J.B.

1989-01-01

Since iodide (I-) inhibits TSH stimulation of cAMP formation, which mediates most of the effects of the hormone, it has been assumed that this accounts for the inhibitory action of iodide on the thyroid. However, TSH stimulation of 32P incorporation into phospholipids and stimulation of thyroid metabolism by other agonists, such as carbachol, phorbol esters, and ionophore A23187, is not cAMP mediated. The present studies examined the effect of iodide on stimulation of glucose oxidation and 32P incorporation into phospholipids by TSH and other agonists to determine if the inhibition of cAMP formation was responsible for the action of iodide. Preincubation of dog thyroid slices for 1 h with iodide (10(-4) M) inhibited TSH-, (Bu)2cAMP-, carbachol-, methylene blue-, 12-O-tetradecanoyl phorbol-13-acetate-, ionophore A23187-, prostaglandin E1-, and cholera toxin-stimulated glucose oxidation. I- also inhibited the stimulation by TSH, 12-O-tetradecanoyl phorbol-13-acetate, carbachol, and ionophore A23187 of 32P incorporation into phospholipids. The inhibition was similar whether iodide was added 2 h before or simultaneously with the agonist. I- itself sometimes stimulated basal glucose oxidation, but had no effect on basal 32P incorporation into phospholipids. The effects of iodide on basal and agonist-stimulated thyroid metabolism were blocked by methimazole (10(-3) M). When dog thyroid slices were preloaded with 32PO4 or [1-14C]glucose, the iodide inhibition of agonist stimulation disappeared, suggesting that the effect of iodide involves the transport process. In conclusion, I- inhibited stimulation of glucose oxidation and 32P incorporation into phospholipids by all agonists, indicating that the effect is independent of the cAMP system and that iodide autoregulation does not only involve this system. Oxidation and organification of iodide are necessary for the inhibition

Effects of Alkali and Counter Ions in Sn-Beta Catalyzed Carbohydrate Conversion

DEFF Research Database (Denmark)

Elliot, Samuel G.; Tolborg, Søren; Madsen, Robert

2018-01-01

Alkali ions have been shown to strongly influence the catalytic behavior of stannosilicates in the conversion of carbohydrates. An effect of having alkali ions present is a pronounced increase in selectivity towards methyl lactate. Mechanistic details of this effect have remained obscure and are ......Alkali ions have been shown to strongly influence the catalytic behavior of stannosilicates in the conversion of carbohydrates. An effect of having alkali ions present is a pronounced increase in selectivity towards methyl lactate. Mechanistic details of this effect have remained obscure...... and are herein addressed experimentally through kinetic experiments and isotope tracking. Alkali ions have a differential effect in competing reaction pathways: they promote the rate of carbon-carbon bond breakage of carbohydrate substrates, but decrease the rates of competing dehydration pathways. Further...... addition of alkali inhibits activity of Sn-Beta in all major reaction pathways. The alkali effects on product distributions and on rates of product formation are similar, thus pointing to a kinetic reaction control and to irreversible reaction steps in the main pathways. Additionally, an effect...

Freezing of liquid alkali metals as screened ionic plasmas

International Nuclear Information System (INIS)

Badirkhan, Z.; Rovere, M.; Tosi, M.P.

1990-08-01

The relationship between Wigner crystallization of the classical ionic plasma and the liquid-solid transition of alkali metals is examined within the density wave theory of freezing. Freezing of the classical plasma on a rigid neutralizing background into the bcc structure is first re-evaluated, in view of recent progress in the determination of its thermodynamic functions by simulation and of the known difficulties of the theory relating to the order parameter at the (200) star of reciprocal lattice vectors. Freezing into the fcc structure is also considered in this context and found to be unfavoured. On allowing for long-wavelength deformability of the background, the ensuing appearance of a volume change on freezing into the bcc structure is accompanied by reduced stability of the fluid phase and by an increase in the entropy of melting. Freezing of alkali metals into the bcc structure is next evaluated, taking their ionic pair structure as that of an ionic plasma reference fluid screened by conduction electrons and asking that the correct ionic coupling strength at liquid-solid coexistence should be approximately reproduced. The ensuring values of the volume and entropy changes across the phase transition, as estimated from the theory by two alternative routes, are in reasonable agreement with experiment. The order parameters of the phase transition, excepting the (200) one, conform rather closely to a Gaussian behaviour and yield a Lindemann ratio in reasonable agreement with the empirical value for melting of bcc crystals. It is suggested that ionic ordering at the (200) star in the metal may be (i) assisted by medium range ordering in the conduction electrons, as indicated by differences in X-ray and neutron diffraction intensities from the liquid, and/or (ii) quite small in the hot bcc solid. Such a possible premelting behaviour of bcc metals should be worth testing experimentally by diffraction. (author). 48 refs, 1 fig., 1 tab

3.2. Antibacterial activity of ethynyl-piperidol polymers and their three-iodides

International Nuclear Information System (INIS)

Khalikov, D.Kh.

2012-01-01

The antibacterial activity of ethynyl-piperidol polymers and their three-iodides was studied. The antibacterial films based on iodine with copolymer N-vinyl pyrrolidone, methylmethacrylate and butyl acrylate were obtained. It was found that samples containing 9-10% of iodine in copolymer have the antiseptic properties. The antibacterial properties of three-iodides grafted nitrogen containing polymers with cellulose fibrous materials were considered. The membrane-active properties of homo- and copolymers of ethynyl piperidol derivatives were considered as well.

Reactive Precipitation of Anhydrous Alkali Sulfide Nanocrystals with Concomitant Abatement of Hydrogen Sulfide and Cogeneration of Hydrogen.

Science.gov (United States)

Li, Xuemin; Zhao, Yangzhi; Brennan, Alice; McCeig, Miranda; Wolden, Colin A; Yang, Yongan

2017-07-21

Anhydrous alkali sulfide (M 2 S, M=Li or Na) nanocrystals (NCs) are important materials central to the development of next generation cathodes and solid-state electrolytes for advanced batteries, but not commercially available at present. This work reports an innovative method to directly synthesize M 2 S NCs through alcohol-mediated reactions between alkali metals and hydrogen sulfide (H 2 S). In the first step, the alkali metal is complexed with alcohol in solution, forming metal alkoxide (ROM) and releasing hydrogen (H 2 ). Next, H 2 S is bubbled through the ROM solution, where both chemicals are completely consumed to produce phase-pure M 2 S NC precipitates and regenerate alcohol that can be recycled. The M 2 S NCs morphology may be tuned through the choice of the alcohol and solvent. Both synthetic steps are thermodynamically favorable (ΔG m o <-100 kJ mol -1 ), proceeding rapidly to completion at ambient temperature with almost 100 % atom efficiency. The net result, H 2 S+2 m→M 2 S+H 2 , makes good use of a hazardous chemical (H 2 S) and delivers two value-added products that naturally phase separate for easy recovery. This scalable approach provides an energy-efficient and environmentally benign solution to the production of nanostructured materials required in emerging battery technologies. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

An alkali-metal ion extracted layered compound as a template for a metastable phase synthesis in a low-temperature solid-state reaction: preparation of brookite from K0.8Ti1.73Li0.27O4.

Science.gov (United States)

Ozawa, Tadashi C; Sasaki, Takayoshi

2010-03-15

We have designed a new approach to synthesize brookite, i.e., to extract alkali-metal ions from K(0.8)Ti(1.73)Li(0.27)O(4) (KTLO) and to apply simultaneous heat treatment to the remaining lepidocrocite-type layers of TiO(6) octahedra. For the alkali-metal ion extraction and the simultaneous heat treatment, KTLO was heated at 400 degrees C with polytetrafluoroethylene (PTFE) in flowing Ar. PTFE has been found to be an effective agent to extract strongly electropositive alkali-metal ions from KTLO because of the strong electronegativity of F as its component. The product of this reaction consists of a mixture of brookite, K(2)CO(3), LiF, and PTFE derivatives, indicating the complete extraction of K(+) and Li(+) from KTLO and formation of brookite from the lepidocrocite-type layer of TiO(6) octahedra as a template. This brookite has a partial replacement of O(2-) with F(-) and/or slight oxygen deficiency; thus, its color is light-bluish gray. Fully oxidized brookite formation and complete decomposition of PTFE derivatives have been achieved by further heating in flowing air, and coproduced alkali-metal salts have been removed by washing in water. Powder X-ray diffraction, Raman spectroscopy, and chemical analysis results have confirmed that the final brookite product treated at 600 degrees C is single phase, and it is white. The method to extract alkali-metal ions from a crystalline material using PTFE is drastically different from the common methods such as soft-chemical and electrochemical reactions. It is likely that this new synthetic approach is applicable to other layered systems to prepare a diverse family of compounds, including novel metastable ones.

Alkali and heavy metal emissions of the PCFB-process; Alkalipaeaestoet PCFB-prosessissa

Energy Technology Data Exchange (ETDEWEB)

Kuivalainen, R.; Eriksson, T.; Lehtonen, P. [Foster Wheeler Energia Oy, Karhula (Finland)

1996-12-01

Pressurized Circulating Fluidized Bed (PCFB) combustion technology has been developed in Karhula R and D Center since 1986. As a part of the development, 10 MW PCFB Test Facility was built in 1989. The Test Facility has been used for performance testing with different coal types through the years 1990-1995 in order to gain data for design and commercialization of the high-efficiency low-emission PCFB combustion technology. The project Y44 `Alkali and heavy metal emissions of the PCFB-process` was part of national LIEKKI 2 research program. The main object of the project was to measure vapor phase Na and K concentrations in the PCFB flue gas after hot gas filter and investigate the effects of process conditions and sorbents on alkali release. The measurements were performed using plasma assisted method by TUT Laboratory of Plasma Technology and wet absorption method of VTT Energy. The measured Na concentrations were below 30 ppb(w) in all measured data points. The results of K were below 10 ppb(w). The accuracies of the both methods are about + 50 % at this concentration range. The scatter of the data covers the effects of different process variables on the alkali emission. The measured emissions are at the same order of magnitude as the guideline emission limits estimated by gas turbine manufacturers. The measurements and development of the analyses methods are planned to be continued during PCFB test runs in spring 1996 for example within Joule II research program. (author)

[Diversity of uncultured actinomycetes in saline-alkali soil from Jiuquan area of Hexi Corridor].

Science.gov (United States)

Li, Hai-yun; Niu, Shi-quan; Kong, Wei-bao; Yan, Wei-ru; Geng, Hui; Han, Cai-hong; Da, Wen-yan; Zhang, Ai-mei; Zhu, Xue-tai

2015-09-01

In order to more accurately understand community structure and diversity of actinomycetes in saline-alkali soil from Jiuquan area of Hexi Corridor, the community structure and diversity from three kinds of soil samples (primary, secondary saline alkali soil and farmland soil) were analyzed using uncultured methods. The results showed that the 16S rDNA clone library of actinomycetales from the primary saline-alkali soil belonged to 19 OTUs, Micrococcineae, Propionibacterineae, Corynebacterineae, Frankineae, Pseudonocardineae and unknown groups of Actinomycetales; the 16S r DNA clone library of actinomycetales from the secondary saline-alkali soil belonged to 14 OTUs, Micrococcineae, Propionibacterineae, Corynebacterineae, Frankineae, Pseudonocardineae and unknown groups of Actinomycetales; the 16S rDNA clone library of farmland soil belonged to 7 OTUs, Micrococcineae, Propionibacterineae, Corynebacterineae, Frankineae, Pseudonocardineae and unknown groups of Actinomycetales; Micrococcineae was the common population in the three soils, and also was the dominant population in primary saline alkali soil and farmland soil. The diversity index and rarefaction curves analysis showed that actinomycetes species richness was in order of primary saline-alkali soil > secondary saline-alkali soil > farmland soil. The dilution curves of primary saline-alkali soil and secondary saline-alkali soil were not leveled off, which indicated the actinomycetes diversity in saline-alkali soil was more enriched than the actual. The rich and diverse actinomycetes resources in saline-alkali soil from Jiuquan area of Hexi Corridor provide important data on the actinomycetes ecology distribution research, exploitation and utilization in saline-alkali soil.

Vapor phase carbonylation of dimethyl ether and methyl acetate with supported transition metal catalysts

International Nuclear Information System (INIS)

Shikada, T.; Fujimoto, K.; Tominaga, H.O.

1986-01-01

The synthesis of acetic acid (AcOH) from methanol (MeOH) and carbon monoxide has been performed industrially in the liquid phase using a rhodium complex catalyst and an iodide promoter. The selectivity to AcOH is more than 99% under mild conditions (175 0 C, 28 atm). The homogeneous rhodium catalyst has been also effective for the synthesis of acetic anhydride (Ac 2 O) by carbonylation of dimethyl ether (DME) or methyl acetate (AcOMe). However, rhodium is one of the most expensive metals and its proved reserves are quite limited. It is highly desired, therefore, to develop a new catalyst as a substitute for rhodium. The authors have already reported that nickel supported on active carbon exhibits an excellent activity for the vapor phase carbonylation of MeOh in the presence of iodide promoter and under moderately pressurized conditions. In addition, corrosive attack on reactors by iodide compounds is expected to be negligible in the vapor phase system. In the present work, vapor phase carbonylation of DME and AcOMe on nickel-active carbon (Ni/A.C.) and molybdenum-active carbon (Mo/A.C.) catalysts was studied

Mechanistic aspects of ingested chlorine dioxide on thyroid function: impact of oxidants on iodide metabolism

International Nuclear Information System (INIS)

Bercz, J.P.; Jones, L.L.; Harrington, R.M.; Bawa, R.; Condie, L.

1986-01-01

Toxicological studies dealing with recent findings of health effects of drinking water disinfectants are reviewed. Experiments with monkeys and rodents indicate that the biological activity of ingested disinfectants is expressed via their chemical interaction with the mucosal epithelia, secretory products, and nutritional contents of the alimentary tract. Evidence exists that a principal partner of this redox interaction is the iodide of nutritional origin that is ubiquitous in the gastrointestinal tract. Thus the observation that subchronic exposure to chlorine dioxide (ClO 2 ) in drinking water decreases serum thyroxine levels in mammalian species can be best explained with changes produced in the chemical form of the bioavailable iodide. Ongoing and previously reported mechanistic studies indicate that oxidizing agents such as chlorine-based disinfectants oxidize the basal iodide content of the gastrointestinal tract. The resulting reactive iodine species readily attaches to organic matter by covalent bonding. Evidence suggests that the extent to which such iodinated organics are formed is proportional to the magnitude of the electromotive force and stoichiometry of the redox couple between iodide and the disinfectant. Because the extent of thyroid uptake of the bioavailable iodide does not decrease during ClO 2 ingestion, it seems that ClO 2 does not cause iodide deficiency of sufficient magnitude to account for the decease in hormonogenesis. Absorption of one or more of iodinated molecules, e.g., nutrient, hormones, or cellular constituents of the alimentary tract having thyromimetic or thyroid inhibitory properties, is a better hypothesis for the effects seen

Horizontal Ampoule Growth and Characterization of Mercuric Iodide at Controlled Gas Pressures for X-Ray and Gamma Ray Spectrometers

International Nuclear Information System (INIS)

Douglas, S.; McGregor Elsa; Ariesanti Bridget Corcoran

2004-01-01

The project developed a new method for producing high quality mercuric iodide crystals of x-ray and gamma spectrometers. Included are characterization of mercuric iodide crystal properties as a function of growth environment and fabrication and demonstration of room-temperature-operated high-resolution mercuric iodide spectrometers

Multicompartmental model for iodide, thyroxine, and triiodothyronine metabolism in normal and spontaneously hyperthyroid cats

Energy Technology Data Exchange (ETDEWEB)

Hays, M.T.; Broome, M.R.; Turrel, J.M.

1988-06-01

A comprehensive multicompartmental kinetic model was developed to account for the distribution and metabolism of simultaneously injected radioactive iodide (iodide*), T3 (T3*), and T4 (T4*) in six normal and seven spontaneously hyperthyroid cats. Data from plasma samples (analyzed by HPLC), urine, feces, and thyroid accumulation were incorporated into the model. The submodels for iodide*, T3*, and T4* all included both a fast and a slow exchange compartment connecting with the plasma compartment. The best-fit iodide* model also included a delay compartment, presumed to be pooling of gastrosalivary secretions. This delay was 62% longer in the hyperthyroid cats than in the euthyroid cats. Unexpectedly, all of the exchange parameters for both T4 and T3 were significantly slowed in hyperthyroidism, possibly because the hyperthyroid cats were older. None of the plasma equivalent volumes of the exchange compartments of iodide*, T3*, or T4* was significantly different in the hyperthyroid cats, although the plasma equivalent volume of the fast T4 exchange compartments were reduced. Secretion of recycled T4* from the thyroid into the plasma T4* compartment was essential to model fit, but its quantity could not be uniquely identified in the absence of multiple thyroid data points. Thyroid secretion of T3* was not detectable. Comparing the fast and slow compartments, there was a shift of T4* deiodination into the fast exchange compartment in hyperthyroidism. Total body mean residence times (MRTs) of iodide* and T3* were not affected by hyperthyroidism, but mean T4* MRT was decreased 23%. Total fractional T4 to T3 conversion was unchanged in hyperthyroidism, although the amount of T3 produced by this route was increased nearly 5-fold because of higher concentrations of donor stable T4.

Multicompartmental model for iodide, thyroxine, and triiodothyronine metabolism in normal and spontaneously hyperthyroid cats

International Nuclear Information System (INIS)

Hays, M.T.; Broome, M.R.; Turrel, J.M.

1988-01-01

A comprehensive multicompartmental kinetic model was developed to account for the distribution and metabolism of simultaneously injected radioactive iodide (iodide*), T3 (T3*), and T4 (T4*) in six normal and seven spontaneously hyperthyroid cats. Data from plasma samples (analyzed by HPLC), urine, feces, and thyroid accumulation were incorporated into the model. The submodels for iodide*, T3*, and T4* all included both a fast and a slow exchange compartment connecting with the plasma compartment. The best-fit iodide* model also included a delay compartment, presumed to be pooling of gastrosalivary secretions. This delay was 62% longer in the hyperthyroid cats than in the euthyroid cats. Unexpectedly, all of the exchange parameters for both T4 and T3 were significantly slowed in hyperthyroidism, possibly because the hyperthyroid cats were older. None of the plasma equivalent volumes of the exchange compartments of iodide*, T3*, or T4* was significantly different in the hyperthyroid cats, although the plasma equivalent volume of the fast T4 exchange compartments were reduced. Secretion of recycled T4* from the thyroid into the plasma T4* compartment was essential to model fit, but its quantity could not be uniquely identified in the absence of multiple thyroid data points. Thyroid secretion of T3* was not detectable. Comparing the fast and slow compartments, there was a shift of T4* deiodination into the fast exchange compartment in hyperthyroidism. Total body mean residence times (MRTs) of iodide* and T3* were not affected by hyperthyroidism, but mean T4* MRT was decreased 23%. Total fractional T4 to T3 conversion was unchanged in hyperthyroidism, although the amount of T3 produced by this route was increased nearly 5-fold because of higher concentrations of donor stable T4

Condensed phase preparation of 2,3-pentanedione

Science.gov (United States)

Miller, D.J.; Perry, S.M.; Fanson, P.T.; Jackson, J.E.

1998-11-03

A condensed phase process for the preparation of purified 2,3-pentanedione from lactic acid and an alkali metal lactate is described. The process uses elevated temperatures between about 200 to 360 C for heating a reaction mixture of lactic acid and an alkali metal lactate to produce the 2,3-pentanedione in a reaction vessel. The 2,3-pentanedione produced is vaporized from the reaction vessel and condensed with water. 5 figs.

Magnetic properties of free alkali and transition metal clusters

International Nuclear Information System (INIS)

Heer, W. de; Milani, P.; Chatelain, A.

1991-01-01

The Stern-Gerlach deflections of small alkali clusters (N<6) and iron clusters (10< N<500) show that the paramagnetic alkali clusters always have a nondeflecting component, while the iron clusters always deflect in the high field direction. Both of these effects appear to be related to spin relaxation however in the case of alkali clusters it is shown that they are in fact caused by avoided level crossing in the Zeeman diagram. For alkali clusters the relatively weak couplings cause reduced magnetic moments where levels cross. For iron clusters however the total spin is strongly coupled to the molecular framework. Consequently this coupling is responsible for avoided level crossing which ultimately cause the total energy of the cluster to decrease with increasing magnetic field so that the iron clusters will deflect in one direction when introduced in an inhomogeneous magnetic field. Experiment and theory are discussed for both cases. (orig.)

Clustering of nucleosides in the presence of alkali metals: Biologically relevant quartets of guanosine, deoxyguanosine and uridine observed by ESI-MS/MS.

Science.gov (United States)

Aggerholm, Tenna; Nanita, Sergio C; Koch, Kim J; Cooks, R Graham

2003-01-01

Electrospray ionization (ESI) mass spectra of nucleosides, recorded in the presence of alkali metals, display alkali metal ion-bound quartets and other clusters that may have implications for understanding non-covalent interactions in DNA and RNA. The tetramers of guanosine and deoxyguanosine and also their metaclusters (clusters of clusters), cationized by alkali metals, were observed as unusually abundant magic number clusters. The observation of these species in the gas phase parallels previous condensed-phase studies, which show that guanine derivatives can form quartets and metaclusters of quartets in solution in the presence of metal cations. This parallel behavior and also internal evidence suggest that bonding in the guanosine tetramers involves the bases rather than the sugar units. The nucleobases thymine and uracil are known to form magic number pentameric adducts with K+, Cs+ and NH4+ in the gas phase. In sharp contrast, we now show that the nucleosides uridine and deoxythymidine do not form the pentameric clusters characteristic of the corresponding bases. More subtle effects of the sugars are evident in the fact that adenosine and cytidine form numerous higher order clusters with alkali metals, whereas deoxyadenosine and deoxycytidine show no clustering. It is suggested that hydrogen bonding between the bases in the tetramers of dG and rG are the dominant interactions in the clusters, hence changing the ribose group to deoxyribose (and vice versa) generally has little effect. However, the additional hydroxyl group of RNA nucleosides enhances the non-selective formation of higher-order aggregates for adenosine and cytidine and results in the lack of highly stable magic number clusters. Some clusters are the result of aggregation in the course of ionization (ESI) whereas others appear to be intrinsic to the solution being examined. Copyright 2003 John Wiley & Sons, Ltd.

Mechanisms of Retinal Damage after Ocular Alkali Burns.

Science.gov (United States)

Paschalis, Eleftherios I; Zhou, Chengxin; Lei, Fengyang; Scott, Nathan; Kapoulea, Vassiliki; Robert, Marie-Claude; Vavvas, Demetrios; Dana, Reza; Chodosh, James; Dohlman, Claes H

2017-06-01

Alkali burns to the eye constitute a leading cause of worldwide blindness. In recent case series, corneal transplantation revealed unexpected damage to the retina and optic nerve in chemically burned eyes. We investigated the physical, biochemical, and immunological components of retinal injury after alkali burn and explored a novel neuroprotective regimen suitable for prompt administration in emergency departments. Thus, in vivo pH, oxygen, and oxidation reduction measurements were performed in the anterior and posterior segment of mouse and rabbit eyes using implantable microsensors. Tissue inflammation was assessed by immunohistochemistry and flow cytometry. The experiments confirmed that the retinal damage is not mediated by direct effect of the alkali, which is effectively buffered by the anterior segment. Rather, pH, oxygen, and oxidation reduction changes were restricted to the cornea and the anterior chamber, where they caused profound uveal inflammation and release of proinflammatory cytokines. The latter rapidly diffuse to the posterior segment, triggering retinal damage. Tumor necrosis factor-α was identified as a key proinflammatory mediator of retinal ganglion cell death. Blockade, by either monoclonal antibody or tumor necrosis factor receptor gene knockout, reduced inflammation and retinal ganglion cell loss. Intraocular pressure elevation was not observed in experimental alkali burns. These findings illuminate the mechanism by which alkali burns cause retinal damage and may have importance in designing therapies for retinal protection. Copyright © 2017 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Developments in mercuric iodide gamma ray imaging

Energy Technology Data Exchange (ETDEWEB)

Patt, B E; Beyerle, A G; Dolin, R C; Ortale, C [EG and G Energy Measurements, Inc., Goleta, CA (USA). Santa Barbara Operations

1989-11-01

A mercuric iodide (HgI{sub 2}) gamma ray imaging array and camera system previously described have been characterized for spatial and energy resolution. Based on these data a new camera is being developed to more fully exploit the potential of the array. Characterization results and design criteria for the new camera will be presented. (orig.).

Synergistic Effect of Azadirachta Indica Extract and Iodide Ions on the Corrosion Inhibition of Aluminium in Acid Media

Energy Technology Data Exchange (ETDEWEB)

Arab, S. T.; Al- Turkustani, A. M.; Al- Dhahiri, R. H. [King Abd El- Aziz University, Jeddah (Saudi Arabia)

2008-06-15

The synergistic action caused by iodide ions on the corrosion inhibition of aluminium (Al) in 0.5 M HCl in the presence of Azadirachta Indica (AZI) plant extract has been investigated using potintiodynamic polarization and impedance techniques. It is found that AZI extract inhibits the corrosion of aluminium in 0.5 M HCl. The inhibition efficiency increases with the increase in AZI extract concentration, until 24% v/v of AZI extract, then Inh.% is decreased with father increase in AZI extract concentration. The adsorption of this extract in the studied concentration is found to obey Frewendlish adsorption isotherm. The addition of iodide ions enhances the inhibition efficiency to a considerable extent. The increase in Inh.% values in presence of fixed concentration of iodide ions indicates that AZI extract forms an insoluble complex at lower AZI extract concentrations by undergoing a joint adsorption. But at higher concentrations of AZI extract, competitive adsorption is found between iodide ions and the formed complex leading to less Inh.%. The Inh.% decreased in presence of iodide ions with AZI extract than in presence of AZI extract alone at all studied iodide concentrations. The synergism parameter S {sub θ} is defined and calculated from surface coverage values. This parameter in the case of AZI extract is found to be more than unity, indicating that the enhanced inhibition efficiency caused by the addition of iodide ions.

Spectroscopic and Kinetic Measurements of Alkali Atom-Rare Gas Excimers

Science.gov (United States)

2009-11-04

vapors – Exciplex molecules absorb over much greater bandwidth • Control of inherent high optical gain to minimize ASE and optimize laser oscillation... Exciplex assisted diode Pumped Alkali Laser (XPAL) • Education of a future generation of laser scientists VG09-227-2 Physical Sciences Inc. Novel Approach...This new laser exploits the optical properties of weakly-bound alkali/rare-gas exciplexes for pumping the 2P1/2, 3/2 alkali atomic excited states 4

Conduction bands and invariant energy gaps in alkali bromides

NARCIS (Netherlands)

Boer, P.K. de; Groot, R.A. de

1998-01-01

Electronic structure calculations of the alkali bromides LiBr, NaBr, KBr, RbBr and CsBr are reported. It is shown that the conduction band has primarily bromine character. The size of the band gaps of bromides and alkali halides in general is reinterpreted.

The method of determination of micro quantities of labeled iodide in carrier free Na125 solution

International Nuclear Information System (INIS)

Kholbaev, A.Kh.; Shilin, E.A.

1996-01-01

The method of determination of microquantities of labelled iodide in Na 125 carrier-free solution was elaborated. This method permits to increase the sensitivity and radiation protection of the determination of labeled iodide. It includes oxidation of iodide by iodate in diluted sulphuric acid with molar concentration 0,03-0,04 mole/l. The extraction of I 2 is made by toluene. The coloured solution is made and optical density is measured at λ=640 nm at the 10 mm optical path .(A.A.D.)

Alkali cyanides; destructive distillation

Energy Technology Data Exchange (ETDEWEB)

Clancy, J C

1925-12-02

The destructive distillation of carbonaceous substances can be accomplished by heating them in a bath of molten alkali and cyanide. Liquid hydrocarbons are produced. The separation of the cyanide from the coke or carbonaceous residues by filtration leaves a substantial quantity of cyanide absorbed by the carbon. A feasible method for removal has been developed by mixing the mixture of cyanide and coke with sodium carbonate or other alkali in the molten state, then treating this substance with nitrogen with or without ammonia to convert most of the carbon to cyanide. The carbonaceous material may be mixed with a liquid hydrocarbon such as petroleum, shale oil, or heavy tar oil, heated, and introduced below the surface of the liquid cyanide which partially decomposes and hydrogenates the coal to increase the yield of hydrocarbons. Dry ammonia may be bubbled through the reaction mixture to effect agitation and to form more cyanide.

40 CFR 721.2565 - Alkylated sulfonated diphenyl oxide, alkali and amine salts.

Science.gov (United States)

2010-07-01

..., alkali and amine salts. 721.2565 Section 721.2565 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.2565 Alkylated sulfonated diphenyl oxide, alkali and... substances identified as alkylated sulfonated diphenyl oxide, alkali salt (PMN P-93-352) and alkylated...

Synthesis and photoluminescence of Sm3+ doped alkali alkaline earth borate hosts NaBa4 (BO3)3 and LiSr4(BO3)3

International Nuclear Information System (INIS)

Chauhan, A.V.; Nagpure, P.A.; Omanwar, S.K.

2012-01-01

In this paper we report the photoluminescence of Sm 3+ doped alkali alkaline borate hosts NaBa 4 (BO 3 ) 3 and LiSr 4 (BO 3 ) 3 . For the synthesis of alkali alkaline borate hosts NaBa 4 (BO 3 ) 3 and LiSr 4 (BO 3 ) 3 doped with different concentrations of Sm 3+ ions, we used the novel combustion technique. The phase purity of the hosts was confirmed by the powder XRD technique. The photoluminescence of the phosphors were carried out within 300 to 700 nm wavelength range. The phosphor shows intense orange red (602 nm) emission for near UV excitation. The FTIR spectra of the phase pure hosts have also been reported. (author)

Photochemical versus biological production of methyl iodide during Meteor 55

Science.gov (United States)

Richter, U.; Wallace, D.

2003-04-01

The flux of methyl iodide from sea to air represents the largest flux of iodine from the ocean to the atmosphere. Surface water concentrations and hence fluxes are particularly high in tropical regions. This flux may be responsible for the enrichment of iodine in the marine aerosol and may contribute to important processes in the marine boundary layer, including particle formation. Methyl iodide is commonly referred to as a biogenic gas, with both macroalgae and phytoplankton identified as important sources. On the other hand experimental and field data have shown the importance of photochemical production that is not necessarily associated directly with biological activity. During the Meteor cruise 55 along 11°N in the tropical Atlantic Ocean, a series of experiments were conducted to examine the biological vs. photochemical production of methyl iodide. A total of eight separate experiments were conducted. Production of CH3I in quartz glass flasks during 24 hour incubations (dark and natural sunlight) was measured under three experimental treatments: untreated seawater, filtered seawater (0.1 um pore size filter to exclude most phytoplankton and bacteria), and seawater that was poisoned with mercuric chloride. There were two clear findings from these experiments: (1) methyl iodide production was significantly higher in all the incubations that were exposed to the light than in the dark incubations; (2) there was no significant difference between CH3I production under the three experimental treatments. These results argue very strongly for the primary importance of photochemical production of CH3I as opposed to biogenic production at least for the tropical open ocean surface waters. Further experiments are required to investigate the reactants involved, their sources, the wavelength and depth dependence of production, etc. as well as (possibly related) sink processes.

A model for additive transport in metal halide lamps containing mercury and dysprosium tri-iodide

NARCIS (Netherlands)

Beks, M.L.; Haverlag, M.; Mullen, van der J.J.A.M.

2008-01-01

The distribution of additives in a metal halide lamp is examined through numerical modelling. A model for a lamp containing sodium iodide additives has been modified to study a discharge containing dysprosium tri-iodide salts. To study the complex chemistry the method of Gibbs minimization is used

Thermochemical properties of the alkali hydroxides: A review

International Nuclear Information System (INIS)

Konings, R.J.M.; Cordfunke, E.H.P.

1989-01-01

The formation of volatile alkali hydroxides as a result of high-temperature steam corrosion plays an important role in nuclear technology. For the modeling of the volatilization processes, reliable thermodynamic data are required. In the present paper recent physico-chemical experiments by the authors will be discussed and the thermochemical properties of the alkali hydroxide series will be evaluated. (orig.)

Possible applications of alkali-activated systems in construction

OpenAIRE

Boháčová, J.; Staněk, S.; Vavro, M. (Martin)

2013-01-01

This paper deals with the possibilities of using alkali-activated systems in construction. This article summarizes the advantages and disadvantages of geopolymer in comparison to Portland cement, summarizes research and practical applications of alkali-activated materials in our country and abroad, and provides an overview of directions where these alternative inorganic binders can be in the future very well applied.

Continuing studies of alkali-aggregate reactions in concrete

International Nuclear Information System (INIS)

Gilliot, J.E.; Beddoes, R.J.

1981-01-01

Studies are continuing into the nature of the different forms of the alkali-aggregate reaction. No general agreement exists as to the detailed nature of the expansive mechanisms. Alkali is known to react internally with opaline silica because of its microporous nature whereas reaction at the external surface is thought to be relatively more important in the case of quartz. A combination of Fourier shape and surface texture analysis, microscopy and osmotic studies is being used to obtain information on the relative importance of these two forms of alkaline attack on silica. Analytical methods are much more rapid than dimensional change tests and it is hoped that a better understanding of the expansion mechanism will lead to more certain recognition of potentially alkali expansive aggregates

The effect of temperature on radiolysis of iodide ion diluted aqueous solutions

International Nuclear Information System (INIS)

Gorbovitskaya, T.; Tiliks, J.

1996-01-01

In order to investigate the radiolysis of iodine containing aqueous solutions a flow type facility - Iodine Thermoradiation Facility (ITF) has been designed. It has a possibility to irradiate aqueous solutions in the steel vessel with 60 Co γ-rays and continuously (on line) to analyze the products of radiolysis both in liquid and in gaseous phases. By means of ITF the formation of I ox (I 2 + I 3 - + HOI), IO 3 - , H 2 O 2 was studied in 10 -5 - 10 -3 mol/dm 3 CsI aqueous solutions by their radiolysis at dose rate 4.5 kGv/h for six hours in region of temperatures from 313 to 404 K. Under similar conditions, some experiments in glass ampoules were also performed. The steady-state concentrations of I ox and IO 3 - decreased with increasing temperature as linear function of inverted temperature. The effect decreased with decreasing concentration of iodide ion. As the result, at high temperatures (T≥380 K) the steady-state concentration of I ox does not depend essentially on the iodide ion initial concentration. Molecular iodine (I 2 ) released from the solution was the main radiolysis product in gaseous phase. Its steady-state concentration increased with increasing temperature because of iodine solubility in the water and decreased at the same time because the radiolytic iodine concentrations decreased. Therefore the most volatility of irradiated 10 -3 and 10 -4 M CsI solutions was observed at the temperature about 350 K. The volatility of 10 -5 M solutions gradually decreased with increasing temperature. The experimental data were explained on the base of the hypothesis that the reaction between I 2 and radiolytic H 2 O 2 was the limit one determining the temperature dependence of I ox and IO 3 - steady-state concentrations. Its activation energy was estimated to be 27,5 kcal.mol -1 . The temperature dependence for reaction (IO - + H 2 O 2 ) was also estimated. (author) 8 figs., 1 tab., 17 refs

A comparative study of semi-empirical interionic potentials for alkali halides - II

International Nuclear Information System (INIS)

Khwaja, F.A.; Naqvi, S.H.

1985-08-01

A comprehensive study of some semi-empirical interionic potentials is carried out through the calculation of the cohesive energy, relative stability and pressure induced solid-solid phase transformations in alkali halides. The theoretical values of these properties of the alkali halides are obtained using a new set of van der Waals coefficients and zero-point energy in the expression for interionic potential. From the comparison of the present calculations with some previous sophisticated ab-initio quantum-mechanical calculations and other semi-empirical approaches, it is concluded that the present calculations in the simplest central pairwise interaction description with the new values of the van der Waals coefficients and zero-point energy are in better agreement with the experimental data than the previous calculations. It is also concluded that in some cases the better choice of the interionic potential alone in the simplest semi-empirical picture of interaction gives an agreement of the theoretical predictions with the experimental data much superior to the ab-initio quantum mechanical approaches. (author)

The effects of potassium and rubidium hydroxide on the alkali-silica reaction

International Nuclear Information System (INIS)

Shomglin, K.; Turanli, L.; Wenk, H.-R.; Monteiro, P.J.M.; Sposito, G.

2003-01-01

Expansion of mortar specimens prepared with an aggregate of mylonite from the Santa Rosa mylonite zone in southern California was studied to investigate the effect of different alkali ions on the alkali-silica reaction in concrete. The expansion tests indicate that mortar has a greater expansion when subjected to a sodium hydroxide bath than in a sodium-potassium-rubidium hydroxide bath. Electron probe microanalysis (EPMA) of mortar bars at early ages show that rubidium ions, used as tracer, were present throughout the sample by the third day of exposure. The analysis also shows a high concentration of rubidium in silica gel from mortar bars exposed to bath solutions containing rubidium. The results suggest that expansion of mortar bars using ASTM C 1260 does not depend on the diffusion of alkali ions. The results indicate that the expansion of alkali-silica gel depends on the type of alkali ions present. Alkali-silica gel containing rubidium shows a lower concentration of calcium, suggesting competition for the same sites

Nuclear detonation, thyroid cancer and potassium iodide prophylaxis

Directory of Open Access Journals (Sweden)

Viroj Wiwanitkit

2011-01-01

Full Text Available The recent nuclear disaster at Japan has raised global concerns about effects of radioactive leakage in the environment, associated hazards, and how they can be prevented. In this article, we have tried to explain about the guidelines laid down by World Health Organization for a potassium iodide prophylaxis following a nuclear disaster, and its mechanism of action in preventing thyroid cancer. Data was collected mainly from the studies carried out during the Chernobyl disaster of Russia in 1986 and the hazardous effects especially on the thyroid gland were studied. It was seen that radioactive iodine leakage from the nuclear plants mainly affected the thyroid gland, and especially children were at a higher risk at developing the cancers. Potassium Iodide prophylaxis can be administered in order to prevent an increase in the incidence of thyroid cancers in the population of an area affected by a nuclear disaster. However, one has to be cautious while giving it, as using it without indication has its own risks.

Electrolytic method for the production of lithium using a lithium-amalgam electrode

Science.gov (United States)

Cooper, John F.; Krikorian, Oscar H.; Homsy, Robert V.

1979-01-01

A method for recovering lithium from its molten amalgam by electrolysis of the amalgam in an electrolytic cell containing as a molten electrolyte a fused-salt consisting essentially of a mixture of two or more alkali metal halides, preferably alkali metal halides selected from lithium iodide, lithium chloride, potassium iodide and potassium chloride. A particularly suitable molten electrolyte is a fused-salt consisting essentially of a mixture of at least three components obtained by modifying an eutectic mixture of LiI-KI by the addition of a minor amount of one or more alkali metal halides. The lithium-amalgam fused-salt cell may be used in an electrolytic system for recovering lithium from an aqueous solution of a lithium compound, wherein electrolysis of the aqueous solution in an aqueous cell in the presence of a mercury cathode produces a lithium amalgam. The present method is particularly useful for the regeneration of lithium from the aqueous reaction products of a lithium-water-air battery.

Properties of Hooked Steel Fibers Reinforced Alkali Activated Material Concrete

OpenAIRE

Faris M. A.; Abdullah Mohd Mustafa Al Bakri; Ismail Khairul Nizar; Muniandy Ratnasamy; Mahmad Nor Aiman; Putra Jaya Ramadhansyah; Waried Wazien A. Z.

2016-01-01

In this study, alkali activated material was produced by using Class F fly ash from Manjung power station, Lumut, Perak, Malaysia. Fly ash then was activated by alkaline activator which is consisting of sodium silicate (Na2SiO3) and sodium hydroxide (NaOH). Hooked end steel fibers were added into the alkali activated material system with percentage vary from 0 % – 5 %. Chemical compositions of fly ash were first analyzed by using x-ray fluorescence (XRF). All hardened alkali activated materia...

Behaviour of gaseous alkali compounds in coal gasification; Kaasumaisten alkaliyhdisteiden kaeyttaeytyminen kivihiilien kaasutuksessa

Energy Technology Data Exchange (ETDEWEB)

Nykaenen, J [Imatran Voima Oy, Vantaa (Finland)

1997-10-01

In this project the behaviour of alkali compounds emitting from CO{sub 2}/O{sub 2}- and airblown gasification are studied. This research project is closely connected to an EU-project coordinated by the Delft University of Technology (DUT). In that project alkali emissions from a 1.6 MW pilot plant will be measured. The results from those measurements will be compared with the calculations performed in this LIEKKI 2 project. The equilibrium calculations show that the major gaseous alkali compounds emitting from combustion and gasification are chlorides and hydroxides. This applies both to air- and CO{sub 2}/O{sub 2}-blown processes. In all the cases studied the concentration of gaseous alkali compounds is determined mainly by the amount of chlorides. The key parameters, with respect to alkali behaviour, are the temperature of the process and chlorine content of the coal. By cooling the gases down to 600 deg C prior to a ceramic filter the alkali concentration can be kept about at 100 ppbv. In combustion, the addition of calcium carbonate increases the amount of gaseous alkali compounds by decreasing the amount of alkali sulphates. In the case of gasification the importance of limestone is negligible. The difference between air- and CO{sub 2}/O{sub 2}-blown processes, in terms of gaseous alkali emissions, is small. This is because CO{sub 2} concentration of the gas does not have a strong impact on alkali chlorides. Furthermore, the effect of CO{sub 2}/O{sub 2}-ratio of the recirculation process is negligible. (orig.)

Grotthuss Transport of Iodide in EMIM/I3 Ionic Crystal.

Science.gov (United States)

McDaniel, Jesse G; Yethiraj, Arun

2018-01-11

Highly ionic environments can mediate unusual chemical reactions that would otherwise be considered impossible based on chemical intuition. For example, the formation of a chemical bond between two iodide anions to form a divalent polyiodide anion is seemingly prohibited due to Coulombic repulsion. Using ab initio molecular dynamics simulations, we show that in the 1-ethyl-3-methylimidazolium (EMIM)/I 3 ionic crystal, the reactive formation of divalent and even trivalent polyiodide anions occurs with extremely small energetic barriers, due to the electrostatic field of the ionic lattice. A practical consequence of this anomalous reactivity is that iodide anions are efficiently transported within the crystal through a "Grotthuss-exchange" mechanism involving bond-breaking and forming events. We characterize two distinct transport pathways, involving both I 4 2- and I 7 3- intermediates, with fast transport of iodide resulting from the release of an I - anion on the opposite side of the intermediate species from the initial bond formation. The ordered cation arrangement in the crystal provides the necessary electrostatic screening for close approach of anions, suggesting a new counterintuitive approach to obtain high ionic conductivity. This new design principle could be used to develop better solid-state electrolytes for batteries, fuel cells, and supercapacitors.

Defluidization in fluidized bed gasifiers using high-alkali content fuels

DEFF Research Database (Denmark)

Narayan, Vikas; Jensen, Peter Arendt; Henriksen, Ulrik Birk

2016-01-01

samples,agglomeration could be attributed to viscous silicate melts formed from reaction of inorganic alkalineand alkali earth species with silica from the bed particles. A mathematical model that addresses the defluidization behavior of alkali-rich samples was developed based on the experiments performed...... and calcium, which may form viscous melts that adhere on the surface of the colliding bed particles and bind them to form agglomerates. In this paper, studies were made to understand the behavior of inorganic elements (mainly K, Si and Ca) on agglomeration and de-fluidization of alkali rich bed...... in the bench-scale fluidized bed reactor as well as on results from literature. The model was then used topredict the de-fluidization behavior of alkali-rich bed material in a large-scale LTCFB gasifier....

Sorption of microamount of colloidal silver iodide on hydrated iron(III) oxide

International Nuclear Information System (INIS)

Kepak, F.; Nova, J.

1975-01-01

Sorption of a microamount of colloidal silver iodide labelled with 131 I on hydrated iron/III/ oxide suspension was studied. The sorption dependence upon pH, sorbent amount, and inert electrolyte concentration has revealed that sorption of silver iodide reaches no more than 63%. The sorption lasted one hour during which the maximum value was reached. Desorption time was one hour, as well. Except for measuring the sorption dependence on pH, the sorption pH was 7.0, temperature 24+-2 0 C. (F.G.)

Potassium iodide stockpiling

International Nuclear Information System (INIS)

Krimm, R.W.

1983-01-01

After examination by the Federal Emergency Management Agency (FEMA) and other federal agencies of federal policy on the use and distribution of potassium iodide (KI) as a thyroid-blocking agent for use in off-site preparedness around commercial nuclear powerplants, FEMA believes the present shelf life of KI is too short, that the minimum ordering quantities are an obstacle to efficient procurement, and that the packaging format offered by the drug industry does not meet the wishes of state and local government officials. FEMA has asked assistance from the Food and Drug Administration in making it possible for those states wishing to satisfy appropriate requirements to do so at the minimum cost to the public. Given an appropriate packaging and drug form, there appears to be no reason for the federal government to have further involvement in the stockpiling of KI

Detection of apoptotic cells using propidium iodide staining

NARCIS (Netherlands)

Newbold, Andrea; Martin, Ben P.; Cullinane, Carleen; Bots, Michael

2014-01-01

Flow cytometry assays are often used to detect apoptotic cells in in vitro cultures. Depending on the experimental model, these assays can also be useful in evaluating apoptosis in vivo. In this protocol, we describe a propidium iodide (PI) flow cytometry assay to evaluate B-cell lymphomas that have

Influence of Alkali Treatment on Anodized Titanium Alloys in Wollastonite Suspension

Directory of Open Access Journals (Sweden)

Alicja Kazek-Kęsik

2017-08-01

Full Text Available The surface modification of titanium alloys is an effective method to improve their biocompatibility and tailor the material to the desired profile of implant functionality. In this work, technologically-advanced titanium alloys—Ti-15Mo, Ti-13Nb-13Zr and Ti-6Al-7Nb—were anodized in suspensions, followed by treatment in alkali solutions, with wollastonite deposition from the powder phase suspended in solution. The anodized samples were immersed in NaOH or KOH solution with various concentrations with a different set of temperatures and exposure times. Based on their morphologies (observed by scanning electron microscope, the selected samples were investigated by Raman and X-ray photoelectron spectroscopy (XPS. Titaniate compounds were formed on the previously anodized titanium surfaces. The surface wettability significantly decreased, mainly on the modified Ti-15Mo alloy surface. Titanium alloy compounds had an influence on the results of the titanium alloys’ surface modification, which caused the surfaces to exhibit differential physical properties. In this paper, we present the influence of the anodization procedure on alkali treatment effects and the properties of obtained hybrid coatings.

Spectra of alkali atoms

International Nuclear Information System (INIS)

Santoso, Budi; Arumbinang, Haryono.

1981-01-01

Emission spectra of alkali atoms has been determined by using spectrometer at the ultraviolet to infra red waves range. The spectra emission can be obtained by absorption spectrophotometric analysis. Comparative evaluations between experimental data and data handbook obtained by spark method were also presented. (author tr.)

Effects of Potassium Iodide on Low Avid Immunological Reactions ...

African Journals Online (AJOL)

In identical test conditions keeping appropriate control, the following ... Abstract. Background: Selective in‑vivo anti‑fungal action of potassium iodide (KI) is an enigma, but .... mechanism of action of the drug against selective infections. In fact, if ...

Alpha-lipoic acid induces sodium iodide symporter expression in TPC-1 thyroid cancer cell line

International Nuclear Information System (INIS)

Choi, Hyun-Jeung; Kim, Tae Yong; Ruiz-Llorente, Sergio; Jeon, Min Ji; Han, Ji Min; Kim, Won Gu; Shong, Young Kee; Kim, Won Bae

2012-01-01

Introduction: Patients with metastatic thyroid cancers that do not uptake iodine need effective therapeutic option. Differentiation-inducing agents have been tried to restore functional expression of sodium iodide symporter (NIS) without success. Our objective was to assess the effect of alpha-lipoic acid (ALA), known as potential antioxidant, on expression of sodium iodide symporter in thyroid cancer cells. Methods: Human thyroid cancer-derived cell lines, TPC-1, were treated with ALA, and changes in NIS mRNA and protein expression were measured. ALA's effect on NIS gene promoter was evaluated, and functional NIS expression was assessed by iodide uptake assay. Results: Treatment with ALA increased NIS mRNA expression up to ten folds of control dose-dependently after 24 h of exposure. ALA increased NIS promoter activity, and increased iodide uptake by 1.6 fold. ALA induced expression of NIS protein, but had no significant effect on the plasma membrane trafficking. ALA increased phosphorylation of CREB and nuclear translocation of pCREB, and co-treatment of ALA and trichostatin A increased iodide uptake by three folds in TPC-1 cells. Conclusions: ALA is a potential agent to increase NIS transcription in TPC-1. It could be used as an adjunctive agent to increase efficacy of radioiodine therapy if combined with a strategy to increase NIS protein trafficking to cell membrane.

Sputtering/redeposition analysis of alkali-based tungsten composites for limiter/divertor applications

International Nuclear Information System (INIS)

DeWald, A.B.; Krauss, A.R.; Gruen, D.M.; Valentine, M.G.

1986-07-01

Composites of porous tungsten infiltrated with alkali metal-bearing alloys have been projected as a means of reducing plasma impurities and sputter erosion in magnetic fusion devices. Self-sustaining alkali metal overlayers have been observed to inhibit erosion of the underlying structural substrate by 2X to 10X. The alkali metal itself, insofar as it sputters as a secondary ion, is trapped at the surface by sheath potential and tangential magnetic fields. Self-regeneration of the alkali metal coating is obtained by thermal and radiation-induced segregation from the bulk

Aqueous Dissolution of Silver Iodide and Associated Iodine Release Under Reducing Conditions with Sulfide

International Nuclear Information System (INIS)

Yaohiro Inagaki; Toshitaka Imamura; Kazuya Idemitsu; Tatsumi Arima; Osamu Kato; Hidekazu Asano; Tsutomu Nishimura

2007-01-01

Aqueous dissolution tests of silver iodide (AgI) were performed in Na 2 S solutions in order to evaluate, empirically, dissolution of AgI to release iodine under reducing conditions with sulfide. The results indicated that AgI dissolves to release iodine being controlled by mainly precipitation of Ag 2 S. However, the dissolution of AgI can be depressed to proceed, and the thermodynamic equilibrium cannot be attained easily. Solid phase analysis for the reacted AgI suggested that a thin layer of solid silver forming at AgI surface may evolve to be protective against transportation of reactant species, which can lead to the depression in the dissolution of AgI. (authors)

Small-molecule inhibitors of sodium iodide sym-porter function

International Nuclear Information System (INIS)

Lecat-Guillet, N.; Merer, G.; Lopez, R.; Rousseau, B.; Ambroise, Y.; Pourcher, T.

2008-01-01

The Na + /l - sym-porter (NIS) mediates iodide uptake into thyroid follicular cells. Although NIS has been cloned and thoroughly studied at the molecular level, the biochemical processes involved in post-translational regulation of NIS are still unknown. The purpose of this study was to identify and characterize inhibitors of NIS function. These small organic molecules represent a starting point in the identification of pharmacological tools for the characterization of NIS trafficking and activation mechanisms. screening of a collection of 17020 drug-like compounds revealed new chemical inhibitors with potencies down to 40 nM. Fluorescence measurement of membrane potential indicates that these inhibitors do not act by disrupting the sodium gradient. They allow immediate and total iodide discharge from preloaded cells in accord with a specific modification of NIS activity, probably through distinct mechanisms. (authors)

Small-molecule inhibitors of sodium iodide sym-porter function

Energy Technology Data Exchange (ETDEWEB)

Lecat-Guillet, N.; Merer, G.; Lopez, R.; Rousseau, B.; Ambroise, Y. [CEA, DSV, Dept Bioorgan Chem et Isotop Labelling, Inst Biol et Biotechnol iBiTecS, F-91191 Gif Sur Yvette (France); Pourcher, T. [Univ Nice Sophia Antipolis, Dept Biochem et Nucl Toxicol, F-06107 Nice (France)

2008-07-01

The Na{sup +}/l{sup -} sym-porter (NIS) mediates iodide uptake into thyroid follicular cells. Although NIS has been cloned and thoroughly studied at the molecular level, the biochemical processes involved in post-translational regulation of NIS are still unknown. The purpose of this study was to identify and characterize inhibitors of NIS function. These small organic molecules represent a starting point in the identification of pharmacological tools for the characterization of NIS trafficking and activation mechanisms. screening of a collection of 17020 drug-like compounds revealed new chemical inhibitors with potencies down to 40 nM. Fluorescence measurement of membrane potential indicates that these inhibitors do not act by disrupting the sodium gradient. They allow immediate and total iodide discharge from preloaded cells in accord with a specific modification of NIS activity, probably through distinct mechanisms. (authors)

Kinetic studies of the radical oxidation in gaseous phase of organic iodides and of the formation of iodine oxide particles under the simulated conditions of a nuclear reactor containment submitted to a severe accident

International Nuclear Information System (INIS)

Zhang, S.

2012-01-01

Within the framework of the research in the nuclear reactor safety field, the iodine oxides formation by organic iodides destruction in the containment has been studied with the means of the atmospheric chemistry field. The destruction kinetics and their activation energy of organic iodides by . OH and . O radical has been quantified by a Flash Photolysis system able to monitor the oxidant radicals by resonance fluorescence. Those results have been published and some of them for the first time in the literature. The mechanisms leading to the organic iodides destruction are either by a hydrogen atom abstraction, either by the formation of a complex, depending on the organic iodide involved. Then, certain kinetics reactions have been updated in the IODAIR code. Other reactions have been added based on the recent literature available. A comparison of the kinetics destruction of CH 3 I by . OH and . O with IODAIR and the global kinetics of destruction in ASTEC/IODE showed a difference of about 2 which shows the importance of these two radicals (and mainly . O) in those destruction processes. The other main path of destruction would be by electron radiation. Other radicals like . H and . N would not contribute significantly to organic iodides destruction. A sensitivity analysis highlighted that organic iodides would mostly be destroyed into iodine oxides with a almost complete conversion within a few hours. Finally, an atmospheric chamber has been used to quantify iodine oxides growth, density and composition. Under the conditions studied, their formation is fast. Particles sizes of about 200-400 nm are formed within a few hours. The main parameters influencing their growth are the relative humidity and the presence of ozone (whose function is to create . O and . OH radicals). (author)

Kinetic modeling of the purging of activated carbon after short term methyl iodide loading

International Nuclear Information System (INIS)

Friedrich, V.; Lux, I.

1991-01-01

A bimolecular reaction model containing the physico-chemical parameters of the adsorption and desorption was developed earlier to describe the kinetics of methyl iodide retention by activated carbon adsorber. Both theoretical model and experimental investigations postulated constant upstream methyl iodide concentration till the maximum break-through. The work reported here includes the extension of the theoretical model to the general case when the concentration of the challenging gas may change in time. The effect of short term loading followed by purging with air, and an impulse-like increase in upstream gas concentration has been simulated. The case of short term loading and subsequent purging has been experimentally studied to validate the model. The investigations were carried out on non-impregnated activated carbon. A 4 cm deep carbon bed had been challenged by methyl iodide for 30, 90, 120 and 180 min and then purged with air, downstream methyl iodide concentration had been measured continuously. The main characteristics of the observed downstream concentration curves (time and slope of break-through, time and amplitude of maximum values) showed acceptable agreement with those predicted by the model

Ultrafast electron dynamics at alkali/ice structures adsorbed on a metal surface

International Nuclear Information System (INIS)

Meyer, Michael

2011-01-01

The goal of this work is to study the interaction between excess electrons in water ice structures adsorbed on metal surfaces and other charged or neutral species, like alkali ions, or chemically reactive molecules, like chlorofluorocarbons (CFC), respectively. The excess electrons in the ice can interact with the ions directly or indirectly via the hydrogen bonded water molecules. In both cases the presence of the alkali influences the population, localization, and lifetime of electronic states of excess electrons in the ice adlayer. These properties are of great relevance when considering the highly reactive character of the excess electrons, which can mediate chemical reactions by dissociative electron attachment (DEA). The influence of alkali adsorption on electron solvation and transfer dynamics in ice structures is investigated for two types of adsorption configurations using femtosecond time-resolved two-photon photoelectron spectroscopy. In the first system alkali atoms are coadsorbed on top of a wetting amorphous ice film adsorbed on Cu(111). At temperatures between 60 and 100 K alkali adsorption leads to the formation of positively charged alkali ions at the ice/vacuum interface. The interaction between the alkali ions at the surface and the dipole moments of the surrounding water molecules results in a reorientation of the water molecules. As a consequence new electron trapping sites, i.e. at local potential minima, are formed. Photoinjection of excess electrons into these alkali-ion covered amorphous ice layers, results in the trapping of a solvated electron at an alkali-ion/water complex. In contrast to solvation in pure amorphous ice films, where the electrons are located in the bulk of the ice layer, solvated electrons at alkali-ion/water complexes are located at the ice/vacuum interface. They exhibit lifetimes of several picoseconds and show a fast energetic stabilization. With ongoing solvation, i.e. pump-probe time delay, the electron transfer is

Uptake of Iodide From Water in Atlantic Halibut Larvae (Hippoglossus Hippoglossus L.)

DEFF Research Database (Denmark)

Moren, Mari; Sloth, Jens Jørgen; Hamre, Kristin

2008-01-01

The natural diet of marine fish larvae, copepods, contain 60-350 mg I kg(-1), while live feed used in commercial hatcheries have iodine concentrations in the range of 1 mg kg(-1). Seawater is also considered to be an important source of iodine for marine fish. The question asked in this study is ......M. The uptake was partly blocked by perchlorate (ClO3-) which is a known inhibitor of the sodium iodide symporter. This indicates that the Atlantic halibut larvae accumulate iodide through both specific and non-specific uptake pathways....

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

Citrate, malate and alkali content in commonly consumed diet sodas: implications for nephrolithiasis treatment.

Science.gov (United States)

Eisner, Brian H; Asplin, John R; Goldfarb, David S; Ahmad, Ardalanejaz; Stoller, Marshall L

2010-06-01

Citrate is a known inhibitor of calcium stone formation. Dietary citrate and alkali intake may have an effect on citraturia. Increasing alkali intake also increases urine pH, which can help prevent uric acid stones. We determined citrate, malate and total alkali concentrations in commonly consumed diet sodas to help direct dietary recommendations in patients with hypocitraturic calcium or uric acid nephrolithiasis. Citrate and malate were measured in a lemonade beverage commonly used to treat hypocitraturic calcium nephrolithiasis and in 15 diet sodas. Anions were measured by ion chromatography. The pH of each beverage was measured to allow calculation of the unprotonated anion concentration using the known pK of citric and malic acid. Total alkali equivalents were calculated for each beverage. Statistical analysis was done using Pearson's correlation coefficient. Several sodas contained an amount of citrate equal to or greater than that of alkali and total alkali as a lemonade beverage commonly used to treat hypocitraturic calcium nephrolithiasis (6.30 mEq/l citrate as alkali and 6.30 as total alkali). These sodas were Diet Sunkist Orange, Diet 7Up, Sprite Zero, Diet Canada Dry Ginger Ale, Sierra Mist Free, Diet Orange Crush, Fresca and Diet Mountain Dew. Colas, including Caffeine Free Diet Coke, Coke Zero, Caffeine Free Diet Pepsi and Diet Coke with Lime, had the lowest total alkali (less than 1.0 mEq/l). There was no significant correlation between beverage pH and total alkali content. Several commonly consumed diet sodas contain moderate amounts of citrate as alkali and total alkali. This information is helpful for dietary recommendations in patients with calcium nephrolithiasis, specifically those with hypocitraturia. It may also be useful in patients with low urine pH and uric acid stones. Beverage malate content is also important since malate ingestion increases the total alkali delivered, which in turn augments citraturia and increases urine pH. Copyright

Iodine from bacterial iodide oxidization by Roseovarius spp. inhibits the growth of other bacteria.

Science.gov (United States)

Zhao, Dan; Lim, Choon-Ping; Miyanaga, Kazuhiko; Tanji, Yasunori

2013-03-01

Microbial activities in brine, seawater, or estuarine mud are involved in iodine cycle. To investigate the effects of the microbiologically induced iodine on other bacteria in the environment, a total of 13 bacteria that potentially participated in the iodide-oxidizing process were isolated from water or biofilm at a location containing 131 μg ml(-1) iodide. Three distinct strains were further identified as Roseovarius spp. based on 16 S rRNA gene sequences after being distinguished by restriction fragment length polymorphism analysis. Morphological characteristics of these three Roseovarius spp. varied considerably across and within strains. Iodine production increased with Roseovarius spp. growth when cultured in Marine Broth with 200 μg ml(-1) iodide (I(-)). When 10(6) CFU/ml Escherichia coli, Pseudomonas aeruginosa, and Bacillus pumilus were exposed to various concentrations of molecular iodine (I(2)), the minimum inhibitory concentrations (MICs) were 0.5, 1.0, and 1.0 μg ml(-1), respectively. However, fivefold increases in the MICs for Roseovarius spp. were obtained. In co-cultured Roseovarius sp. IOB-7 and E. coli in Marine Broth containing iodide (I(-)), the molecular iodine concentration was estimated to be 0.76 μg ml(-1) after 24 h and less than 50 % of E. coli was viable compared to that co-cultured without iodide. The growth inhibition of E. coli was also observed in co-cultures with the two other Roseovarius spp. strains when the molecular iodine concentration was assumed to be 0.52 μg ml(-1).

Accelerated degradation of methyl iodide by agrochemicals.

Science.gov (United States)

Zheng, Wei; Papiernik, Sharon K; Guo, Mingxin; Yates, Scott R

2003-01-29

The fumigant methyl iodide (MeI, iodomethane) is considered a promising alternative to methyl bromide (MeBr) for soil-borne pest control in high-cash-value crops. However, the high vapor pressure of MeI results in emissions of a significant proportion of the applied mass into the ambient air, and this may lead to pollution of the environment. Integrating the application of certain agrochemicals with soil fumigation provides a novel approach to reduce excessive fumigant emissions. This study investigated the potential for several agrochemicals that are commonly used in farming operations, including fertilizers and nitrification inhibitors, to transform MeI in aqueous solution. The pseudo-first-order hydrolysis half-life (t(1/2)) of MeI was approximately 108 d, while the transformation of MeI in aqueous solutions containing selected agrochemicals was more rapid, with t(1/2) agrochemicals on the rate of MeI degradation in soil was also determined. Adsorption to soil apparently reduced the availability of some nitrification inhibitors in the soil aqueous phase and lowered the degradation rate in soil. In contrast, addition of the nitrification inhibitors thiourea and allylthiourea to soil significantly accelerated the degradation of MeI, possibly due to soil surface catalysis. The t(1/2) of MeI was 300 h).

Confinement Effects in Low-Dimensional Lead Iodide Perovskite Hybrids

NARCIS (Netherlands)

Kamminga, Machteld E.; Fang, Honghua; Filip, Marina R.; Giustino, Feliciano; Baas, Jacobus; Blake, Graeme R.; Loi, Maria Antonietta; Palstra, Thomas T. M.

2016-01-01

We use a layered solution crystal growth technique to synthesize high-quality single crystals of phenylalkylammonium lead iodide organic/inorganic hybrid compounds. Single-crystal X-ray diffraction reveals low-dimensional structures consisting of inorganic sheets separated by bilayers of the organic

Exchange of Na+ and K+ between water vapor and feldspar phases at high temperature and low vapor pressure

Science.gov (United States)

Fournier, R.O.

1976-01-01

In order to determine whether gas (steam) containing a small amount of dissolved alkali chloride is effective in promoting base exchange of Na+ and K+ among alkali feldspars and coexisting brine or brine plus solid salt, experiments were carried out at 400-700??C and steam densities ranging down to less than 0.05. For bulk compositions rich in potassium, the low pressure results are close to previous high-pressure results in composition of the fluid and coexisting solid phase. However, when the bulk composition is more sodic, alkali feldspars are relatively richer in potassium at low pressure than at high pressure. This behaviour corresponds to enrichment of potassium in the gas phase relative to coexisting brine and precipitation of solid NaCl when the brine plus gas composition becomes moderately sodic. The gas phase is very effective in promoting base exchange between coexisting alkali feldspars at high temperature and low water pressure. This suggests that those igneous rocks which contain coexisting alkali feldspars out of chemical equilibrium either remained very dry during the high-temperature part of their cooling history or that the pore fluid was a gas containing very little potassium relative to sodium. ?? 1976.

Study of Iodine Behavior in the Gas Phase during a Severe Accident

International Nuclear Information System (INIS)

Kim, Hanchul; Cho, Yeonghun; Ryu, Myunghyun

2014-01-01

Among the iodine species, the organic iodides produced from the reaction between iodine and organics such as paint, are not easily trapped by the filters during the containment venting following a severe accident. Korea Institute of Nuclear Safety (KINS) has been studying this issue, joining international research programs such as ISTP-EPICUR, OECDBIP and OECD-STEM. In the course of this study, a simple iodine model, RAIM (Radio-Active Iodine chemistry Model) has been developed (Oh et al., 2011), based on the IMOD methodology, and other previous studies. This paper deals with our recent activities on this study, including the development of the model for the iodine reactions in gas phase. Iodine reactions in gas phase were modeled and added to the RAIM code, taking into account several relevant reactions such as formation of ARP, iodine oxide, and organic iodides in gas phase. RAIM was then applied to analyze the S2-6-5-2 test for which iodine-loaded coupons were tested in gas phase. The analysis results show a reasonable estimation of volatile iodine concentration with the desorption rate constant of about 10 -6 s -1 , while those of the other iodine species overestimated for the whole period of the test. It reveals the need to determine appropriate values for the rate constants for formation of iodine oxides and organic iodides

Language and Style in Zaynab Alkali's The Stillborn | Azuike ...

African Journals Online (AJOL)

This paper examines the language and style of Zaynab Alkali's The Stillborn. Alkali's style in The Stillborn lies in her effective deployment of linguo-literary resources to tell the story. The study scrutinizes the nexus of figures of speech and linguistic artifacts, which link the events and characters that populate her novel and ...

Influence of alkali metal oxides and alkaline earth metal oxides on the mitigation of stress corrosion cracking in CANDU fuel sheathing

Energy Technology Data Exchange (ETDEWEB)

Metzler, J.; Ferrier, G.A.; Farahani, M.; Chan, P.K.; Corcoran, E.C., E-mail: Joseph.Metzler@rmc.ca [Royal Military College of Canada, Kingston, ON (Canada)

2015-07-01

This work investigates strategies to mitigate stress corrosion cracking (SCC) in Zircaloy-4 sheathing materials. The CANLUB coatings currently used in CANDU reactors contain both alkali metal and alkaline earth metal impurities, which can exist as oxides (e.g., Na{sub 2}O and CaO). It is believed that when the corrosive fission product iodine reacts with these oxides, the iodine can be sequestered through the formation of an iodide (e.g.,NaI and CaI{sub 2}). The subsequent O{sub 2} release may repair cracks in the protective ZrO{sub 2} layer on the sheathing, shielding the Zircaloy-4 sheathing from further corrosive fission product attack. For this investigation, O{sub 2} gas, Na{sub 2}O, and CaO were separately introduced into an environment wherein slotted Zircaloy-4 rings endure mechanical stresses in iodine vapour at high temperatures. Controlled additions of O{sub 2} gas created a slight reduction in the corrosive attack on Zircaloy-4 sheathing, while the inclusion of Na{sub 2}O and CaO lead to greater reductions. (author)

First application of supported ionic liquid phase (SILP) catalysis for continuous methanol carbonylation.

Science.gov (United States)

Riisager, Anders; Jørgensen, Betina; Wasserscheid, Peter; Fehrmann, Rasmus

2006-03-07

A solid, silica-supported ionic liquid phase (SILP) rhodium iodide Monsanto-type catalyst system, [BMIM][Rh(CO)2I2]-[BMIM]I-SiO2, exhibits excellent activity and selectivity towards acetyl products in fixed-bed, continuous gas-phase methanol carbonylation.

A procedure for preparing alkali metal hydrides

International Nuclear Information System (INIS)

Lemieux, R.U.; Sanford, C.E.; Prescott, J.F.

1976-01-01

A plain low cost, procedure for the continuous, low temperature preparation of sodium or potassium hydrides using cheap reagents is presented. Said invention is especially concerned with a process of purifying of a catalytic exchange liquid used for deuterium enrichment, in which an alkali metal hydride is produced as intermediate product. The procedure for producing the sodium and potassium hydrides consists in causing high pressure hydrogen to be absorbed by a mixture of at least a lower monoalkylamine and an alkylamide of an alkali metal from at least one of said amines [fr

Density functional study of ferromagnetism in alkali metal thin films

Indian Academy of Sciences (India)

thickness uniform jellium model (UJM), and it is argued that within LSDA or GGA, alkali metal thin films cannot be claimed to have an FM ground state. Relevance of these results to the experiments on transition metal-doped alkali metal thin films ...

Neuropsychiatric manifestations of alkali metal deficiency and excess

Energy Technology Data Exchange (ETDEWEB)

Yung, C.Y.

1984-01-01

The alkali metals from the Group IA of the periodic table (lithium, sodium, potassium, rubidium, cesium and francium) are reviewed. The neuropsychiatric aspects of alkali metal deficiencies and excesses (intoxications) are described. Emphasis was placed on lithium due to its clinical uses. The signs and symptoms of these conditions are characterized by features of an organic brain syndrome with delirium and encephalopathy prevailing. There are no clinically distinctive features that could be reliably used for diagnoses. Sodium and potassium are two essential alkali metals in man. Lithium is used as therapeutic agent in bipolar affective disorders. Rubidium has been investigated for its antidepressant effect in a group of psychiatric disorders. Cesium is under laboratory investigation for its role in carcinogenesis and in depressive illness. Very little is known of francium due to its great instability for experimental study.

Structural Investigation of Alkali Activated Clay Minerals for Application in Water Treatment Systems

Science.gov (United States)

Bumanis, G.; Bajare, D.; Dembovska, L.

2015-11-01

Alkali activation technology can be applied for a wide range of alumo-silicates to produce innovative materials with various areas of application. Most researches focuse on the application of alumo-silicate materials in building industry as cement binder replacement to produce mortar and concrete [1]. However, alkali activation technology offers high potential also in biotechnologies [2]. In the processes where certain pH level, especially alkaline environment, must be ensured, alkali activated materials can be applied. One of such fields is water treatment systems where high level pH (up to pH 10.5) ensures efficient removal of water pollutants such as manganese [3]. Previous investigations had shown that alkali activation technology can be applied to calcined clay powder and aluminium scrap recycling waste as a foam forming agent to create porous alkali activated materials. This investigation focuses on the structural investigation of calcined kaolin and illite clay alkali activation processes. Chemical and mineralogical composition of both clays were determined and structural investigation of alkali activated materials was made by using XRD, DTA, FTIR analysis; the microstructure of hardened specimens was observed by SEM. Physical properties of the obtained material were determined. Investigation indicates the essential role of chemical composition of the clay used in the alkali activation process, and potential use of the obtained material in water treatment systems.

Methyl iodide tests on used adsorbents

International Nuclear Information System (INIS)

Kovach, J.L.

1993-01-01

This paper discusses the history of events leading to the current problems in radioiodine test conditions. These radioiodine tests are performed in the adsorbent media from both safety and non-safety related Nuclear Air Treatment Systems (NATS). The main problem addressed is that currently there are still numerous plant technical specifications for NATS which reference outdated test protocols for the surveillance testing of the radioactive methyl iodide performance of the adsorbents. Recommendations for correcting the test condition problems are presented. 7 refs

Structural, elastic, electronic and optical properties of bi-alkali ...

Indian Academy of Sciences (India)

The structural parameters, elastic constants, electronic and optical properties of the bi-alkali ... and efficient method for the calculation of the ground-state ... Figure 2. Optimization curve (E–V) of the bi-alkali antimonides: (a) Na2KSb, (b) Na2RbSb, (c) Na2CsSb, .... ical shape of the charge distributions in the contour plots.

Adsorption behavior of calcined layered double hydroxides towards removal of iodide contaminants

International Nuclear Information System (INIS)

Lu Liang; He Jing; Wei Min; Evans, D.G.; Duan Xue

2005-01-01

Layered double hydroxides (LDHs), are a class of synthetic anionic clays whose structure can be described as containing brucite-like layers in which some of the divalent cations have been replaced by trivalent ions giving positively-charged sheets. This charge is balanced by intercalation of anions in the hydrated interlayer regions. The general formula is EM 2+ 1-x M 3+ x (OH) 2 ] x+ (A n- ) x/n · mH 2 O, where M 2+ and M 3+ are metal cations for example Mg 2+ and Al 3+ , that occupy octahedral sites in the hydroxide layers, A n- is an exchangeable anion, and x is the ratio M 3+ /(M 2+ + M 3+ ) and the layer charge will depend on the M 2+ /M 3+ ratio. LDHs act as sorbents of anionic species through two types of reactions, namely, anion exchange and reconstruction, which further adds the possibility of recycling and reuse. The sorption of anions from aqueous solutions by structural reconstruction of a calcined LDH is based on a very interesting property of these materials, the so-called memory effect: Calcination of LDHs produces intermediate non-stoichiometric oxides (CLDH) which undergo rehydration in aqueous medium and give back the hydroxide structure with different anions in the interlayers. Radioactive iodide is widely used in biological experiments, medical treatments and in diagnosis. During fission of uranium several iodine species are produced. All the short lived isotopes of iodine, including 1311 (half life 8.04 days), decay and only 127 I (stable) and 129 I (half life 1.59 x 10 7 years) remain as a problem. 129 I is especially considered as one of the key radionuclides that dominate the long-term radiation in underground radioactive waste stores. Iodine is one of the nuclides causing most concern among radioactive anions. Different adsorbents such as zeolites, silica gel, anion exchange paper membrane, activated carbon and activated carbon fibers, have been investigated as potential materials for elimination of iodide from liquid wastes. In this work

Impact of humic acid on the photoreductive degradation of perfluorooctane sulfonate (PFOS) by UV/Iodide process.

Science.gov (United States)

Sun, Zhuyu; Zhang, Chaojie; Chen, Pei; Zhou, Qi; Hoffmann, Michael R

2017-12-15

Iodide photolysis under UV illumination affords an effective method to produce hydrated electrons (e aq - ) in aqueous solution. Therefore, UV/Iodide photolysis can be utilized for the reductive degradation of many recalcitrant pollutants. However, the effect of naturally occurring organic matter (NOM) such as humic and fulvic acids (HA/FA), which may impact the efficiency of UV/Iodide photoreduction, is poorly understood. In this study, the UV photoreductive degradation of perfluorooctane sulfonate (PFOS) in the presence of I - and HA is studied. PFOS undergoes a relatively slow direct photoreduction in pure water, a moderate level of degradation via UV/Iodide, but a rapid degradation via UV/Iodide/HA photolysis. After 1.5 h of photolysis, 86.0% of the initial [PFOS] was degraded in the presence of both I - and HA with a corresponding defluorination ratio of 55.6%, whereas only 51.7% of PFOS was degraded with a defluorination ratio of 4.4% via UV/Iodide illumination in the absence of HA. The relative enhancement in the presence of HA in the photodegradation of PFOS can be attributed to several factors: a) HA enhances the effective generation of e aq - due to the reduction of I 2 , HOI, IO 3 - and I 3 - back to I - ; b) certain functional groups of HA (i.e., quinones) enhance the electron transfer efficiency as electron shuttles; c) a weakly-bonded association of I - and PFOS with HA increases the reaction probability; and d) absorption of UV photons by HA itself produces e aq - . The degradation and defluorination efficiency of PFOS by UV/Iodide/HA process is dependent on pH and HA concentration. As pH increases from 7.0 to 10.0, the enhancement effect of HA improves significantly. The optimal HA concentration for the degradation of 0.03 mM PFOS is 1.0 mg L -1 . Copyright © 2017 Elsevier Ltd. All rights reserved.

The sodium iodide symporter: its implications for imaging and therapy

International Nuclear Information System (INIS)

Spitzweg, C.

2007-01-01

The sodium iodide symporter (NIS) is an intrinsic plasma membrane glycoprotein that mediates the active transport of iodide in the thyroid gland and a number of extrathyroidal tissues, in particular lactating mammary gland. In addition to its key function in thyroid physiology, NIS-mediated iodide accumulation allows diagnostic thyroid scintigraphy as well as therapeutic radioiodine application in benign and malignant thyroid disease. NIS therefore represents one of the oldest targets for molecular imaging and therapy. Based on the effective administration of radioiodine that has been used for over 60 years in the management of follicular cell-derived thyroid cancer, cloning and characterization of the NIS gene has paved the way for the development of a novel cytoreductive gene therapy strategy based on targeted NIS expression in thyroidal and nonthyroidal cancer cells followed by therapeutic application of 131 I or alternative radionuclides, including 188 Re and 211 At. In addition, the possibility of direct and non-invasive imaging of functional NIS expression by 123 I- and 99m Tc-scintigraphy or 124 I-PET-imaging allows the application of NIS as a novel reporter gene. In conclusion, the dual role of NIS as diagnostic and therapeutic gene and the detection of extra-thyroidal endogenous NIS expression in breast cancer open promising perspectives in nuclear medicine and molecular oncology for diagnostic and therapeutic application of NIS outside the thyroid gland. (orig.)

Photoemission spectroscopy study of a multi-alkali photocathode

CERN Document Server

Ettema, A R H

2000-01-01

In this paper a photoemission study of the highest core levels of the elements and the electron escape barrier (work function) in a multi-alkali photocathode are presented. The core levels indicate that the alkali atoms are in an oxidized state and therefore the compound Na sub 2 KSb can be regarded as an ionic semiconductor. The measured escape barrier of the Cs sub 2 O surface layer is determined as 2.3 eV.

Effects of alkali and steaming on mechanical properties of snake fruit (Salacca) fiber

Science.gov (United States)

Darmanto, Seno; Rochardjo, Heru S. B.; Jamasri, Widyorini, Ragil

2017-01-01

The aim of this research is to investigate the effect of alkali treatment and steaming on mechanical properties of Snake Fruit frond fiber. The presence of surface impurities and a lot of hydroxyl groups makes natural fiber less compatible for composite materials reinforcement. Efforts to remove the impurities can be done by physical, chemical and mechanical treatments. This paper reports the treatment of Snake Fruit frond single fiber by subjecting it to alkali treatments with 2%- 8% NaOH for 2 - 6 hours at room temperature. The treatment is then followed by steaming at a pressure of 2 bars in 1 hour. Results show that the treatment of alkali and the alkali-steaming combination can increase cellulose percentage. The tensile tests show that this type of treatment in combination resulted in the higher tensile strength compared to untreated fiber. There is a significant increase in tensile strength with increasing alkali percentage. However, the further increase in the percentage of alkali solution will result in decreasing tensile strength. The highest value of tensile strength after treatment was 275 MPa with 6 hours treatment at alkali percentage of 2 %.

Structure of xanthan gum and cell ultrastructure at different times of alkali stress.

Science.gov (United States)

Luvielmo, Márcia de Mello; Borges, Caroline Dellinghausen; Toyama, Daniela de Oliveira; Vendruscolo, Claire Tondo; Scamparini, Adilma Regina Pippa

2016-01-01

The effect of alkali stress on the yield, viscosity, gum structure, and cell ultrastructure of xanthan gum was evaluated at the end of fermentation process of xanthan production by Xanthomonas campestris pv. manihotis 280-95. Although greater xanthan production was observed after a 24h-alkali stress process, a lower viscosity was observed when compared to the alkali stress-free gum, regardless of the alkali stress time. However, this outcome is not conclusive as further studies on gum purification are required to remove excess sodium, verify the efficiency loss and the consequent increase in the polymer viscosity. Alkali stress altered the structure of xanthan gum from a polygon-like shape to a star-like form. At the end of the fermentation, early structural changes in the bacterium were observed. After alkali stress, marked structural differences were observed in the cells. A more vacuolated cytoplasm and discontinuities in the membrane cells evidenced the cell lysis. Xanthan was observed in the form of concentric circles instead of agglomerates as observed prior to the alkali stress. Copyright © 2015 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

The influence of polycarboxylate-type super-plasticizers on alkali-free liquid concrete accelerators performance

Science.gov (United States)

Guo, Wenkang; Yin, Haibo; Wang, Shuyin; He, Zhifeng

2017-04-01

Through studying on the setting times, cement mortar compressive strength and cement mortar compressive strength ratio, the influence of alkali-free liquid accelerators polycarboxylate-type super-plasticizers on the performance of alkali-free liquid accelerators in cement-based material was investigated. The results showed that the compatibility of super-plasticizers and alkali-free liquid accelerators was excellent. However, the dosage of super-plasticizers had a certain impact on the performance of alkali-free liquid accelerators as follows: 1) the setting times of alkali-free liquid accelerators was in the inverse proportional relationship to the dosage of super-plasticizers; 2)the influence of super-plasticizers dosage on the cement mortar compressive strength of alkali-free liquid accelerators was related to the types of accelerators, where exist an optimum super-plasticizers dosage for cement mortar compressive strength at 28d; 3)the later cement mortar compressive strength with alkali-free liquid accelerators were decreasing with the increment of the super-plasticizers dosage. In the practical application of alkali-free liquid accelerators and super-plasticizer, the dosage of super-plasticizer must be determined by dosage optimization test results.

Decalcification resistance of alkali-activated slag

Energy Technology Data Exchange (ETDEWEB)

Komljenovic, Miroslav M., E-mail: miroslav.komljenovic@imsi.rs [Institute for Multidisciplinary Research, University of Belgrade, Kneza Viseslava 1, 11030 Belgrade (Serbia); Bascarevic, Zvezdana, E-mail: zvezdana@imsi.bg.ac.rs [Institute for Multidisciplinary Research, University of Belgrade, Kneza Viseslava 1, 11030 Belgrade (Serbia); Marjanovic, Natasa, E-mail: natasa@imsi.bg.ac.rs [Institute for Multidisciplinary Research, University of Belgrade, Kneza Viseslava 1, 11030 Belgrade (Serbia); Nikolic, Violeta, E-mail: violeta@imsi.bg.ac.rs [Institute for Multidisciplinary Research, University of Belgrade, Kneza Viseslava 1, 11030 Belgrade (Serbia)

2012-09-30

Highlights: Black-Right-Pointing-Pointer The effects of decalcification on properties of alkali-activated slag were studied. Black-Right-Pointing-Pointer Decalcification was performed by concentrated NH{sub 4}NO{sub 3} solution (accelerated test). Black-Right-Pointing-Pointer Portland-slag cement (CEM II/A-S 42.5 N) was used as a benchmark material. Black-Right-Pointing-Pointer Decalcification led to strength decrease and noticeable structural changes. Black-Right-Pointing-Pointer Alkali-activated slag showed significantly higher resistance to decalcification. - Abstract: This paper analyses the effects of decalcification in concentrated 6 M NH{sub 4}NO{sub 3} solution on mechanical and microstructural properties of alkali-activated slag (AAS). Portland-slag cement (CEM II/A-S 42.5 N) was used as a benchmark material. Decalcification process led to a decrease in strength, both in AAS and in CEM II, and this effect was more pronounced in CEM II. The decrease in strength was explicitly related to the decrease in Ca/Si atomic ratio of C-S-H gel. A very low ratio of Ca/Si {approx}0.3 in AAS was the consequence of coexistence of C-S-H(I) gel and silica gel. During decalcification of AAS almost complete leaching of sodium and tetrahedral aluminum from C-S-H(I) gel also took place. AAS showed significantly higher resistance to decalcification in relation to the benchmark CEM II due to the absence of portlandite, high level of polymerization of silicate chains, low level of aluminum for silicon substitution in the structure of C-S-H(I), and the formation of protective layer of polymerized silica gel during decalcification process. In stabilization/solidification processes alkali-activated slag represents a more promising solution than Portland-slag cement due to significantly higher resistance to decalcification.

Gas phase chemistry and removal of CH3I during a severe accident

International Nuclear Information System (INIS)

Karhu, A.

2001-01-01

The purpose of this literature review was to gather valuable information on the behavior of methyl iodide on the gas phase during a severe accident. The potential of transition metals, especially silver and copper, to remove organic iodides from the gas streams was also studied. Transition metals are one of the most interesting groups in the context of iodine mitigation. For example silver is known to react intensively with iodine compounds. Silver is also relatively inert material and it is thermally stable. Copper is known to react with some radioiodine species. However, it is not reactive toward methyl iodide. In addition, it is oxidized to copper oxide under atmospheric conditions. This may limit the industrial use of copper.(au)

[Using a modified remote sensing imagery for interpreting changes in cultivated saline-alkali land].

Science.gov (United States)

Gao, Hui; Liu, Hui-tao; Liu, Hong-juan; Liu, Jin-tong

2015-04-01

This paper developed a new interpretation symbol system for grading and classifying saline-alkali land, using Huanghua, a cosatal city in Hebei Province as a case. The system was developed by inverting remote sensing images from 1992 to 2011 based on site investigation, plant cover characteristics and features of remote sensing images. Combining this interpretation symbol system with supervising classification method, the information on arable land was obtained for the coastal saline-alkali ecosystem of Huanghua City, and the saline-alkali land area, changes in intensity of salinity-alkalinity and spatial distribution from 1992 to 2011 were analyzed. The results showed that salinization of arable land in Huanghua City alleviated from 1992 to 2011. The severely and moderately saline-alkali land area decreased in 2011 compared with 1992, while the non/slightly saline land area increased. The moderately saline-alkali land in southeast transformed to non/slightly saline-alkaline, while the severely saline-alkali land in west of the city far from the coastal zone became moderately saline-alkaline. The center of gravity (CG) of severely and non/slightly saline-alkali land moved closer the coastline, while that of the moderately saline-alkali land moved from southwest coastal line to northwest. Factors influencing changes in arable land within the saline-alkali ecosystem of Huanghua City were climate, hydrology and human activities.

Influence of alkali metal cations/type of activator on the structure of alkali-activated fly ash - ATR-FTIR studies

Science.gov (United States)

Król, M.; Rożek, P.; Chlebda, D.; Mozgawa, W.

2018-06-01

Coal fly ash as a secondary aluminosiliceous raw material that is commonly used in the so-called geopolymerization process has been activated with different alkali hydroxides solutions: LiOH, NaOH and KOH. Changes in the aluminosilicate structure of the material during alkali-activation have been analyzed in detail on the basis of ATR/FT-IR spectra. These changes mainly affect both the integral intensity and FWHM of bands in the range of 1200-950 cm-1, however dehydration and carbonation process can be also analyzed based on obtaining results.

Hydration of a low-alkali CEM III/B–SiO2 cement (LAC)

International Nuclear Information System (INIS)

Lothenbach, Barbara; Le Saout, Gwenn; Ben Haha, Mohsen; Figi, Renato; Wieland, Erich

2012-01-01

The hydration of a low-alkali cement based on CEM III/B blended with 10 wt.% of nanosilica has been studied. The nanosilica reacted within the first days and 90% of the slag reacted within 3.5 years. C-S-H (Ca/Si ∼ 1.2, Al/Si ∼ 0.12), calcite, hydrotalcite, ettringite and possibly strätlingite were the main hydrates. The pore water composition revealed ten times lower alkali concentrations than in Portland cements. Reducing conditions (HS − ) and a pH value of 12.2 were observed. Between 1 month and 3.5 years of hydration more hydrates were formed due to the ongoing slag reaction but no significant differences in the composition of the pore solution or solid phase assemblage were observed. On the basis of thermodynamic calculations it is predicted that siliceous hydrogarnet could form in the long-term and, in the presence of siliceous hydrogarnet, also thaumasite. Nevertheless, even after 3.5 year hydration, neither siliceous hydrogarnet nor thaumasite have been observed.

Alkali content of fly ash : measuring and testing strategies for compliance : [tech transfer summary].

Science.gov (United States)

2015-04-01

This study investigated the test methods used to determine the : alkali content of fly ash. It also evaluated if high-alkali fly ash : exacerbates alkali-silica reaction in laboratory tests and field : concrete.

Influence of alkali metal hydroxides on corrosion of Zr-base alloys

International Nuclear Information System (INIS)

Jeong, Yong Hwan

1996-01-01

The influence of group-1 alkali hydroxides on different Zr-based alloys have been carried out in static autoclaves at 350 deg C in pressurized water, conditioned in low(0.32 mmol), medium(4.3 mmol) and high(31.5 mmol) equimolar concentration of Li-, Na-, K-, Rb- and Cs-hydroxide. Two types of alloys have been investigated: Zr-Sn-(TRM, Transition metal) and Zr-Sn-Nb-(TRM, Transition metal). From the experiments the cation could be identified as the responsible species for corrosion of Zr alloy in alkalized water. The radius of the cation governs the accelerated corrosion in the pre-transition region of Zr alloy. Incorporation of alkali cation into the zirconium oxide lattice is probably the mechanism which allows the corrosion enhancement for Li and Na and the significant lower effect for the other bases. Nb containing alloys showed lower corrosion resistance than Zr-Sn-TRM alloys in all alkali solutions. Both types of alloys were corroded significantly more in LiOH and NaOH than in the other alkali environments. Lowest corrosive aggressiveness has been found for CsOH followed by KOH. Concluding from the corrosion behavior in the different alkali environments and taking into account the tendency to accelerate the corrosion of Zr alloys, CsOH and KOH are possible alternate alkali for PWR (Pressurized Water Reactor) application. (author)

The 11C-radioisotopic study of methanol conversion on V-MCM-41; the influence of methyl iodide on the transformation

International Nuclear Information System (INIS)

Sarkadi-Priboczki, E.; Szelecsenyi, F.; Kovacs, Z.; Solmaz, A.; Balci, S.; Dogu, T.

2007-01-01

Complete text of publication follows. The MCM-41 mesoporous material has Lewis and even Bronsted acid sites to produce dimethyl ether with some hydrocarbons, while over metal modified MCM-41 mostly formaldehyde and dimethoxy methane (i.e. methylal) or methyl formate are produced. In present experiments V incorporated basically mild acid sites of MCM-41 was prepared by low temperature direct synthesis. The V-MCM-41 has enough main active Lewis sites (by V-) to form formaldehyde and also light Bronsted acid sites to let the adsorbed formaldehyde eliminate and afterwards, with methanol, to form dimethoxy methane in nonoxidative environment. This V-MCM-41 has been tested by ethanol conversion in non-oxidative environments too and diethoxy methane as main product was detected. In present work the methanol conversion, as well as the methanol co-reaction with methyl iodide are studied from the same V-MCM-41 sample using 11 C-technique. The 11 C-labelled radioactive methanol has been already applied for determination of methanol conversion rates on Cu-modified MCM-41. The V-MCM-41 was prepared by direct hydrothermal synthesis method. The adsorption rate of 11 C-methanol and, after the reaction, the desorption rate of the remaining 11 C-derivatives on catalyst were continuously detected by gamma detectors. The derivatives were analyzed by radio-gas chromatography (gas chromatograph with FID coupled on-line with a radioactivity detector). Both dimethyl ether and hydrocarbon formation are also in slight degrees according to weak Lewis and Bronsted acidities. Since the conversion was carried out without added oxygen gas, only the frame oxygen can take part into catalysis. In presence of non-radioactive methyl iodide, the radioactive methanol is converted to radioactive methyl iodide on V-MCM-41. The radio-GC analysis confirmed that the iodide induced change of the reaction performance was reversible i.e. the radioactive methyl iodide was regenerated to non-radioactive methyl

Solubility of 1:1 Alkali Nitrates and Chlorides in Near-Critical and Supercritical Water : 1 Alkali Nitrates and Chlorides in Near-Critical and Supercritical Water

NARCIS (Netherlands)

Leusbrock, Ingo; Metz, Sybrand J.; Rexwinkel, Glenn; Versteeg, Geert F.

2009-01-01

To increase the available data oil systems containing supercritical water and inorganic compounds, all experimental setup was designed to investigate the solubilities of inorganic compounds Ill supercritical water, In this work, three alkali chloride salts (LiCl, NaCl, KCl) and three alkali nitrate

New Microporous Polymer Electrolyte Based on Polysiloxane Grafted with Imidazolium Iodide Moieties for DSSC

Directory of Open Access Journals (Sweden)

Yan Yang

2011-01-01

Full Text Available Two types of polysiloxane grafted with different ratio of imidazolium iodide moieties (IL-SiO2 have been synthesized to develop a micro-porous polymer electrolyte for quasi-solid-state dye-sensitized solar cells. The samples were characterized by 1HNMR, FT-IR spectrum, XRD, TEM and SEM, respectively. Moreover, the ionic conductivity of the electrolytes was measured by electrochemical workstation. Nanostructured polysiloxane containing imidazolium iodide showed excellent compatibility with organic solvent and polymer matrix for its ionic liquid characteristics. Increasing the proportion of imidazolium iodide moieties in polysiloxane improved the electrochemical behavior of the gel polymer electrolyte. A dye-sensitized solar cell with gel polymer electrolyte yielded an open-circuit voltage of 0.70 V, short-circuit current of 11.19 mA cm−2, and the conversion efficiency of 3.61% at 1 sun illumination.

An example of transition from a corrosion process in gaseous phase to corrosion in aqueous environment: the case of Z2CN18-10 stainless steel by iodine and water in vapour phase

International Nuclear Information System (INIS)

Mathieu, Bruno

1990-01-01

This research thesis addresses an example of transition of a corrosion process in gaseous phase towards corrosion in aqueous environment, specifically in the case of the corrosion of the Z2CN18-10 stainless steel by gaseous iodine in presence of water vapour (and possibly nitrogen dioxide). This transition occurs in two steps: initiation in gaseous phase and growth in aqueous environment. This transition is due to hygroscopic properties of mostly chromium iodides and, to a lesser extent, iron iodides. Morphological, electrochemical and thermogravimetry studies have been performed by varying different parameters governing corrosion processes: corrosion temperature, iodine concentration, relative humidity, and reaction time [fr

Alkali Release from Typical Danish Aggregates to Potential ASR Reactive Concrete

DEFF Research Database (Denmark)

Thomsen, Hans Christian Brolin; Grelk, Bent; Barbosa, Ricardo Antonio

Alkali-silica reaction (ASR) in concrete is a well-known deterioration mechanism affecting the long term durability of Danish concrete structures. Deleterious ASR cracking can be significantly reduced or prevented by limiting the total alkali content of concrete under a certain threshold limit......, which in Denmark is recommended to 3 kg/m3 Na2Oeq.. However, this threshold limit does not account for the possible internal contribution of alkali to the concrete pore solution by release from aggregates or external contributions from varies sources. This study indicates that certain Danish aggregates...... are capable of releasing more than 0.46 kg/m3 Na2Oeq. at 13 weeks of exposure in laboratory test which may increase the risk for deleterious cracking due to an increase in alkali content in the concrete....

An alkali ion source based on graphite intercalation compounds for ion mobility spectrometry

International Nuclear Information System (INIS)

Tabrizchi, Mahmoud; Hosseini, Zahra S

2008-01-01

A variety of alkali cation emitters were developed as the ion source for ion mobility spectrometry. The cation emitters were constructed based on alkali ion graphite intercalation compounds (GICs). The compounds were prepared by fusing alkali salts with ground graphite. In order to produce alkali ions, the compounds were loaded on a filament and heated to red. Reactant ions of the form alk + ions were observed for the alkali salts NaCl, KCl.LiCl, CsCl and SrCl. In addition to Na + ions, K + ions were observed at the beginning of thermionic emission from Na-GIC. This is due to the low ionization potential of potassium that exists in trace amounts in sodium salts. In addition to the potassium ion, Na + was observed in the case of LiCl salt. The Na + and K + peaks originating from impurities totally disappeared after about 40 min. However, the thermionic emission of the main ion of the corresponding salt lasted for several days. No negative ions were observed upon reversing the drift field. Selected organic compounds (methyl isobutyl ketone, dimethyl sulfoxide, acetone and tetrahydrofuran) were also ionized via alkali cation attachment reaction. Distinct ion mobility patterns were observed for different substances using one type of alkali reactant ion. However, the ion mobility pattern for a given substance changed when a different alkali reactant ion was used. Ammonia and amines were not ionized when this source was used

Existence of hexachlorocerates (4) of alkali metals

Energy Technology Data Exchange (ETDEWEB)

Kiselev, Yu.M.; Filatov, I.Yu.; Popov, A.I.; Goryachenkova, S.A.; Martynenko, L.I.; Spitsyn, V.I. (Moskovskij Gosudarstvennyj Univ. (USSR))

1985-01-01

A possibility has been studied to prepare alkali metal hexachlorocerates (4) of the composition M/sub 2/CeCl/sub 6/ (M=Li, Na, K, Rb) according to the reaction 2MX + fH/sub 2/CeCl/sub 6/'' ..-->.. 2HX + M/sub 2/CeCl/sub 6/ (X=Cl/sup -/, NO/sub 3//sup -/). Using X-ray phase analysis and low-temperature hTA it has been shown, that under experimental conditions (-65 deg C) the rubidium-cerium chlorocomplex is formed, in which Ce is present in the form of Ce(4). The complex is unstable at approximately 20 deg C and under the effect of moisture gets hydrolyzed with the formation of Ce(3) derivatives. Isomorphism of Rb and Cs hexachlorocerates (4) is established. According to the data of the low-temperature DTA, the authors failed to prepare Li, Na, K hexachlorocerates (4).

Thermochemistry of alkali chloride - lanthanoide(III) chlorides

International Nuclear Information System (INIS)

Blachnik, R.; Selle, D.

1979-01-01

The phase diagrams of the mixtures KCl + GdCl 3 resp. DyCl 3 and of CsCl + PrCl 3 (DyCl 3 , ErCl 3 , and YbCl 3 ) were investigated by differential thermal analysis. In the mixtures of lanthanoide(III) chlorides with CsCl resp. KCl three different stoichiometries of the compounds were found, namely A 3 MCl 6 , A 2 MCl 5 , and AM 2 Cl 7 . Debyeograms of the compounds A 3 MCl 6 and AM 2 Cl 7 reveal, that in the case of the latter type all compounds with the same alkali halide have identical structure, whereas in the A 3 MCl 6 compounds three different types of X-ray patterns were observed. The stabilities of the congruently melting compounds can be estimated by comparing the melting point of the compound with the temperature of an extrapolated eutectic point. (author)

Studying thermal dehydration of double nickel alkali metal pyrophosphates

International Nuclear Information System (INIS)

Bykanova, T.A.; Lavrov, A.V.; AN SSSR, Moscow. Inst. Obshchej i Neorganicheskoj Khimii)

1978-01-01

The methods of thermogravimetry, paper chromatography, infrared spectroscopy and X-ray phase analysis were used in studying the process of thermal dehydration of pyrophosphates of the M 2 Ni 3 (P 2 O 7 ) 2 xnH 2 O type (where n=6, 10; M=Na, K, Rb, Cs, NH 4 ). The dehydration of Cs 2 Ni 3 (P 2 O 7 ) 2 x10H 2 O proceeds in a single stage (endothermal effect at 210 deg C). The exothermal effects at 730 and 690 deg C correspond to the crystallization of the amorphous dehydration products. It has been established that binary pyrophosphates of nickel with alkali metals decompose when heated into Ni 3 (PO 4 ) 2 +MPO 4

Validation of ion chromatography for the determination of transition metal ions along with alkali, alkaline earth metal elements for uranium oxide fuel