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Sample records for complex fluoride salts

  1. Molten fluoride fuel salt chemistry

    International Nuclear Information System (INIS)

    Toth, L.M.; Del Cul, G.D.; Dai, S.; Metcalf, D.H.

    1995-01-01

    The chemistry of molten fluorides is traced from their development as fuels in the Molten Salt Reactor Experiment with important factors in their selection being discussed. Key chemical characteristics such as solubility, redox behavior, and chemical activity are explained as they relate to the behavior of molten fluoride fuel systems. Development requirements for fitting the current state of the chemistry to modern nuclear fuel system are described. It is concluded that while much is known about molten fluoride behavior which can be used effectively to reduce the amount of development required for future systems, some significant molten salt chemical questions must still be addressed. copyright American Institute of Physics 1995

  2. Optical Detection of Sodium Salts of Fluoride, Acetate and ...

    Indian Academy of Sciences (India)

    Administrator

    Optical Detection of Sodium Salts of Fluoride, Acetate and Phosphate by a Diacylhydrazine. Ligand via the Formation of a Colour Alkali Metal Complex. Purnandhu Bose, Ranjan Dutta, I. Ravikumar and Pradyut Ghosh. ∗. Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, 2A & 2B Raja ...

  3. Optical detection of sodium salts of fluoride, acetate and phosphate

    Indian Academy of Sciences (India)

    Optical detection of sodium salts of fluoride, acetate and phosphate by a diacylhydrazine ligand by the formation of a colour alkali metal complex. Purnandhu Bose Ranjan Dutta I ... Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, 2A and 2B Raja S C Mullick Road, Kolkata 700032, India ...

  4. Some metallic materials and fluoride salts for high temperature applications

    International Nuclear Information System (INIS)

    Hosnedl, P.; Hron, M.; Matal, O.

    2009-01-01

    There has been a special Ni base alloy MONICR for high temperature applications in fluoride salt environments developed in the framework of the complex R and D program for the Molten Salt Reactor (MSR) - SPHINX (SPent Hot fuel Incinerator by Neutron fluX) concept development in the Czech Republic. Selected results of MONICR alloy tests and results of semi products fabrication from this alloy are discussed in the paper. The results of the structural materials tests are applied on semi-products and for the design of the testing devices as the autoclave in loop arrangement for high temperature fluoride salts applications. Material properties other Ni base alloys are compared to those of MONICR. Corrosion test results of the alloy A686 in the LiF - NaF - ZrF 4 molten salt are provided and compared to the measured values of the polarizing resistance. (author)

  5. High Temperature Fluoride Salt Test Loop

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, Adam M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Cunningham, Richard Burns [Univ. of Tennessee, Knoxville, TN (United States); Fugate, David L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Holcomb, David Eugene [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kisner, Roger A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Peretz, Fred J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Robb, Kevin R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wilson, Dane F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Yoder, Jr, Graydon L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-12-01

    Effective high-temperature thermal energy exchange and delivery at temperatures over 600°C has the potential of significant impact by reducing both the capital and operating cost of energy conversion and transport systems. It is one of the key technologies necessary for efficient hydrogen production and could potentially enhance efficiencies of high-temperature solar systems. Today, there are no standard commercially available high-performance heat transfer fluids above 600°C. High pressures associated with water and gaseous coolants (such as helium) at elevated temperatures impose limiting design conditions for the materials in most energy systems. Liquid salts offer high-temperature capabilities at low vapor pressures, good heat transport properties, and reasonable costs and are therefore leading candidate fluids for next-generation energy production. Liquid-fluoride-salt-cooled, graphite-moderated reactors, referred to as Fluoride Salt Reactors (FHRs), are specifically designed to exploit the excellent heat transfer properties of liquid fluoride salts while maximizing their thermal efficiency and minimizing cost. The FHR s outstanding heat transfer properties, combined with its fully passive safety, make this reactor the most technologically desirable nuclear power reactor class for next-generation energy production. Multiple FHR designs are presently being considered. These range from the Pebble Bed Advanced High Temperature Reactor (PB-AHTR) [1] design originally developed by UC-Berkeley to the Small Advanced High-Temperature Reactor (SmAHTR) and the large scale FHR both being developed at ORNL [2]. The value of high-temperature, molten-salt-cooled reactors is also recognized internationally, and Czechoslovakia, France, India, and China all have salt-cooled reactor development under way. The liquid salt experiment presently being developed uses the PB-AHTR as its focus. One core design of the PB-AHTR features multiple 20 cm diameter, 3.2 m long fuel channels

  6. Corrosion study in molten fluoride salt

    International Nuclear Information System (INIS)

    Keny, S.J.; Kumbhar, A.G.; Rangarajan, S.; Gupta, V.K.; Maheshwari, N.K.; Vijayan, P.K.

    2013-01-01

    Corrosion behaviors of two alloys viz. Inconel 625 and Inconel 617 were tested in molten fluoride salts of lithium, sodium and potassium (FLiNaK) in the temperature range of 550-750 ℃ in a nickel lined Inconel vessel. Electrochemical polarization (Tafel plot) technique was used for this purpose. For both alloys, the corrosion rate was found to increase sharply beyond 650 ℃ . At 600 ℃ , Inconel 625 showed a decreasing trend in the corrosion rate over a period of 24 hours, probably due to changes in the surface conditions. After fifteen days, re-testing of Inconel 625 in the same melt showed an increase in the corrosion rate. Inconel 625 was found to be more corrosion resistant than Inconel 617. (author)

  7. Liquid Fluoride Salt Experimentation Using a Small Natural Circulation Cell

    Energy Technology Data Exchange (ETDEWEB)

    Yoder Jr, Graydon L [ORNL; Heatherly, Dennis Wayne [ORNL; Williams, David F [ORNL; Elkassabgi, Yousri M. [Texas A& M University, Kingsville; Caja, Joseph [Electrochemical Systems, Inc.; Caja, Mario [ORNL; Jordan, John [Texas A& M University, Kingsville; Salinas, Roberto [Texas A& M University, Kingsville

    2014-04-01

    A small molten fluoride salt experiment has been constructed and tested to develop experimental techniques for application in liquid fluoride salt systems. There were five major objectives in developing this test apparatus: Allow visual observation of the salt during testing (how can lighting be introduced, how can pictures be taken, what can be seen) Determine if IR photography can be used to examine components submerged in the salt Determine if the experimental configuration provides salt velocity sufficient for collection of corrosion data for future experimentation Determine if a laser Doppler velocimeter can be used to quantify salt velocities. Acquire natural circulation heat transfer data in fluoride salt at temperatures up to 700oC All of these objectives were successfully achieved during testing with the exception of the fourth: acquiring velocity data using the laser Doppler velocimeter. This paper describes the experiment and experimental techniques used, and presents data taken during natural circulation testing.

  8. An Overview of Liquid Fluoride Salt Heat Transport Systems

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, David Eugene [ORNL; Cetiner, Sacit M [ORNL

    2010-09-01

    Heat transport is central to all thermal-based forms of electricity generation. The ever increasing demand for higher thermal efficiency necessitates power generation cycles transitioning to progressively higher temperatures. Similarly, the desire to provide direct thermal coupling between heat sources and higher temperature chemical processes provides the underlying incentive to move toward higher temperature heat transfer loops. As the system temperature rises, the available materials and technology choices become progressively more limited. Superficially, fluoride salts at {approx}700 C resemble water at room temperature being optically transparent and having similar heat capacity, roughly three times the viscosity, and about twice the density. Fluoride salts are a leading candidate heat-transport material at high temperatures. Fluoride salts have been extensively used in specialized industrial processes for decades, yet they have not entered widespread deployment for general heat transport purposes. This report does not provide an exhaustive screening of potential heat transfer media and other high temperature liquids such as alkali metal carbonate eutectics or chloride salts may have economic or technological advantages. A particular advantage of fluoride salts is that the technology for their use is relatively mature as they were extensively studied during the 1940s-1970s as part of the U.S. Atomic Energy Commission's program to develop molten salt reactors (MSRs). However, the instrumentation, components, and practices for use of fluoride salts are not yet developed sufficiently for commercial implementation. This report provides an overview of the current understanding of the technologies involved in liquid salt heat transport (LSHT) along with providing references to the more detailed primary information resources. Much of the information presented here derives from the earlier MSR program. However, technology has evolved over the intervening years

  9. Cooperativity of complex salt bridges

    OpenAIRE

    Gvritishvili, Anzor G.; Gribenko, Alexey V.; Makhatadze, George I.

    2008-01-01

    The energetic contribution of complex salt bridges, in which one charged residue (anchor residue) forms salt bridges with two or more residues simultaneously, has been suggested to have importance for protein stability. Detailed analysis of the net energetics of complex salt bridge formation using double- and triple-mutant cycle analysis revealed conflicting results. In two cases, it was shown that complex salt bridge formation is cooperative, i.e., the net strength of the complex salt bridge...

  10. The precipitation of double fluoride salts of uranium

    Energy Technology Data Exchange (ETDEWEB)

    Muir, C. W.A.

    1963-02-15

    Bench-scale kinetic tests were conducted to study the reduction and precipitation reactions involved in the preparation of ammonium uranous fluoride from high-purity uranyl nitrate solutions. Sulphur dioxide and formic acid were used to form the active reducing agent, nascent hyposulphite ion. The reduction was affected in the presence of ammonium fluoride, resulting in the precipitation of the highly insoluble double salt. It was found that uranium was precipituted at a constant rate throughout the progress of the reaction. It is postulated that the reducing agent was continuously regenerated, and that this reaction was rate controlling. As a result of this study, a reaction mechanism is proposed. (auth)

  11. Hydrogen permeation through Flinabe fluoride molten salts for blanket candidates

    Energy Technology Data Exchange (ETDEWEB)

    Nishiumi, Ryosuke, E-mail: r.nishiumi@aees.kyushu-u.ac.jp; Fukada, Satoshi; Nakamura, Akira; Katayama, Kazunari

    2016-11-01

    Highlights: • H{sub 2} diffusivity, solubility and permeability in Flinabe as T breeder are determined. • Effects in composition differences among Flibe, Fnabe and Flinabe are compared. • Changes of pressure dependence of Flinabe permeation rate are clarified. - Abstract: Fluoride molten salt Flibe (2LiF + BeF{sub 2}) is a promising candidate for the liquid blanket of a nuclear fusion reactor, because of its large advantages of tritium breeding ratio and heat-transfer fluid. Since its melting point is higher than other liquid candidates, another new fluoride molten salt Flinabe (LiF + NaF + BeF{sub 2}) is recently focused on because of its lower melting point while holding proper breeding properties. In this experiment, hydrogen permeation behavior through the three molten salts of Flibe (2LiF + BeF{sub 2}), Fnabe (NaF + BeF{sub 2}) and Flinabe are investigated in order to clarify the effects of their compositions on hydrogen transfer properties. After making up any of the three molten salts and purifying it using HF, hydrogen permeability, diffusivity and solubility of the molten salts are determined experimentally by using a system composed of tertiary cylindrical tubes. Close agreement is obtained between experimental data and analytical solutions. H{sub 2} permeability, diffusivity and solubility are correlated as a function of temperature and are compared among the three molten salts.

  12. Thermodynamic investigation of fluoride salts for nuclear energy production

    International Nuclear Information System (INIS)

    Beilmann, Markus

    2013-01-01

    In this work thermodynamic properties of molten fluoride salts and salt mixtures are investigated. Fluoride salts have advantageous properties to be used in energy producing systems based on the conversion from heat to energy like i.e in Molten Salt Reactors. For this purpose it is very important to have detailed information about the heat capacity of the pure salts and salt mixtures. To get a better understanding about the heat capacity in mixtures drop calorimetry measurements of mixtures of LiF with other alkali fluorides were conducted and compared. The investigation of fluoride salts at elevated temperatures is complicated by the fact that fluoride vapour is aggressive to many materials. In order to protect our sensitive measurement equipment the salt samples were encapsulated in nickel crucibles using a laser welding technique and afterwards the whole nickel capsule was measured. This method was verified by the measurement of unmixed CsF and KF where in both examples an excellent agreement with literature data was obtained. Afterwards various intermediate compositions of the systems LiF-KF, LiF-CsF and LiF-RbF were investigated and a general trend according to the difference in cation radii could be established. In combination with literature data for the LiF-NaF system the heat capacity of the liquid state follows the order LiF-NaF 2 -LaF 3 phase diagram was obtained. With the help of mathematical models the phase diagrams can be calculated and also higher order systems can be predicted. The LiF-NaF-CaF 2 -LaF 3 system was calculated with the classical polynomial model and the quasi-chemical model in parallel in order to evaluate which of the two models provide a better extrapolation to higher order systems (ternary or quaternary) based on the related binary systems. The two models behaved very similar at the investigated system and the quasi-chemical model was chosen for further assessments of phase diagrams. This model was selected, since it considers the

  13. Alkali metal cation complexation and solvent interactions by robust chromium(III) fluoride complexes

    DEFF Research Database (Denmark)

    Birk, T.; Magnussen, M.J.; Piligkos, Stergios

    2010-01-01

    )] have been synthesized from mer-[CrF3(py)(3)] and shown to precipitate sodium salts from solution, of which 3[CrF3(Me(3-)tacn)]center dot 2Na(Bph(4)).solv and 6[CrF3(terpy)]center dot 4Na(Bph(4)).solv have been crystallographically characterized. In these clusters, the neutral fluoride complexes bring...

  14. Compatibility studies of potential molten-salt breeder reactor materials in molten fluoride salts

    International Nuclear Information System (INIS)

    Keiser, J.R.

    1977-05-01

    The molten fluoride salt compatibility studies carried out during the period 1974--76 in support of the Molten-Salt Reactor Program are summarized. Thermal-convection and forced-circulation loops were used to measure the corrosion rate of selected alloys. Results confirmed the relationship of time, initial chromium concentration, and mass loss developed by previous workers. The corrosion rates of Hastelloy N and Hastelloy N modified by the addition of 1--3 wt percent Nb were well within the acceptable range for use in an MSBR. 13 figures, 3 tables

  15. A basic study on fluoride-based molten salt electrolysis technology

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Il Soon [Seoul National University, Seoul (Korea); Kim, Kwang Bum [Yonsei University, Seoul (Korea); Park, Byung Gi [Seoul National University, Seoul (Korea)

    2001-04-01

    The objective of this project is to study on the physicochemical properties of fluoride molten salt, to develop numerical model for simulation of molten salt electrolysis, and to establish experimental technique of fluoride molten salt. Physicochemical data of fluoride molten salt are investigated and summarized. The numerical model, designated as REFIN is developed with diffusion-layer theory and electrochemical reaction kinetics. REFIN is benchmarked with published experimental data. REFIN has a capability to simulate multicomponent electrochemical system at transient conditions. Experimental device is developed to measure electrochemical properties of structural material for fluoride molten salt. Ni electrode is measured with cyclic voltammogram in the conditions of 600 .deg. C LiF-BeF{sub 2} and 700 .deg. C LiF-BeF{sub 2}. 74 refs., 23 figs., 57 tabs. (Author)

  16. Thermochemical investigation of molten fluoride salts for Generation IV nuclear applications - an equilibrium exercise

    NARCIS (Netherlands)

    van der Meer, J.P.M.

    2006-01-01

    The concept of the Molten Salt Reactor, one of the so-called Generation IV future reactors, is that the fuel, a fissile material, which is dissolved in a molten fluoride salt, circulates through a closed circuit. The heat of fission is transferred to a second molten salt coolant loop, the heat of

  17. Extraction of fluoride metal complexes by octanols

    International Nuclear Information System (INIS)

    Baklanova, I.V.; Nikolaev, A.I.; Il'in, E.G.; Majorov, V.G.

    2005-01-01

    The extraction of niobium(V) and tantalum(V) by octanols, including 1-octanol, 2-octanol, and iso-octanol (2-ethylhexanol), was studied. The composition of the octanols and their solubility in various aqueous solutions were evaluated. The capacity of the octanols for tantalum(V) and niobium(V), the extraction properties of the octanols, the viscosity of extracts under conditions of metal fluoride extraction, and the temperature dependence of the viscosity of the octanols were studied. The composition of the extracted complexes was studied by IR and NMR spectroscopy and chemical analysis, and the hydration-solvation mechanism of the extraction of tantalum(V) and niobium(V) was supported [ru

  18. Fluoride Increase in Saliva and Dental Biofilm due to a Meal Prepared with Fluoridated Water or Salt: A Crossover Clinical Study.

    Science.gov (United States)

    Lima, Carolina V; Tenuta, Livia M A; Cury, Jaime A

    2018-06-07

    Knowledge about fluoride delivery to oral fluids from foods cooked with fluoridated water and salt is scarce, and no study has evaluated fluoride concentrations in saliva or biofilm during meal consumption. In this randomized double-blind crossover study, 12 volunteers ingested meals (rice, beans, meat, and legumes) prepared with nonfluoridated water and salt (control group), fluoridated water (0.70 mg F/L; water group), and fluoridated salt (183.7 mg F/kg; salt group). Whole saliva was collected before meal ingestion, during mastication, and up to 2 h after meal ingestion. Dental biofilm was collected before and immediately after meal ingestion. Fluoride concentrations in saliva and dental biofilm were determined by an ion-specific electrode. The mean (±standard deviation; n = 4) fluoride concentrations in meals prepared for the control, water, and salt groups were 0.039 ± 0.01, 0.43 ± 0.04, and 1.71 ± 0.32 μg F/g, respectively. The three groups had significantly different fluoride concentrations in saliva collected during mastication (p water > control). The fluoride concentration in saliva returned to baseline 30 min after meal ingestion in the water group but remained high for up to 2 h in the salt group (p = 0.002). The fluoride concentration in biofilm fluid differed only between the salt and control groups (p = 0.008). The mastication of foods cooked with fluoridated water and salt increases fluoride concentrations in oral fluids and may contribute to the local effect of these community-based fluoride interventions on caries control. © 2018 S. Karger AG, Basel.

  19. Disposition of the fluoride fuel and flush salts from the Molten Salt Reactor experiment at Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    Peretz, F.J.

    1996-01-01

    The Molten Salt Reactor Experiment (MSRE) is an 8 MW reactor that was operated at Oak Ridge National Laboratory (ORNL) from 1965 through 1969. The reactor used a unique liquid salt fuel, composed of a mixture of LIF, BeF 2 , ZrF 4 , and UF 4 , and operated at temperatures above 600 degrees C. The primary fuel salt circulation system consisted of the reactor vessel, a single fuel salt pump, and a single primary heat exchanger. Heat was transferred from the fuel salt to a coolant salt circuit in the primary heat exchanger. The coolant salt was similar to the fuel salt, except that it contains only LiF (66%) and BeF, (34%). The coolant salt passed from the primary heat exchanger to an air-cooled radiator and a coolant salt pump, and then returned to the primary heat exchanger. Each of the salt loops was provided with drain tanks, located such that the salt could be drained out of either circuit by gravity. A single drain tank was provided for the non-radioactive coolant salt. Two drain tanks were provided for the fuel salt. Since the fuel salt contained radioactive fuel, fission products, and activation products, and since the reactor was designed such that the fuel salt could be drained immediately into the drain tanks in the event of a problem in the fuel salt loop, the fuel salt drain tanks were provided with a system to remove the heat generated by radioactive decay. A third drain tank connected to the fuel salt loop was provided for a batch of flush salt. This batch of salt, similar in composition to the coolant salt, was used to condition the fuel salt loop after it had been exposed to air and to flush the fuel salt loop of residual fuel salt prior to accessing the reactor circuit for maintenance or experimental activities. This report discusses the disposition of the fluoride fuel and flush salt

  20. Experimental facilities for research of properties and behaviour of fluoride salts

    International Nuclear Information System (INIS)

    Hosnedl, P.; Jilek, M.; Kroc, V.; Pedal, L.; Valenta, V.; Vodicka, J.

    1999-01-01

    SKODA JS s.r.o. (Czech leading nuclear technology manufacturer) prepared and manufactured experimental loops for research and verification of properties and behaviour of fluoride salts for primary and secondary circuit, construction materials and ADTT systems technological components for the operation in the Nuclear Research Institute Rez plc fluorine chemistry laboratory. This paper presents charts and experimental program for molten fluoride salts experimental loops with natural circulation. Further on, the paper describes extension of the loops for research with forced circulation and next works for steam generator model verification and connection with the loop of Energovyzkum Brno. The loops are designed and constructed to obtain a sufficient amount of experience on ADTT technology. The research and utilisation program covers questions of corrosion and intergranular corrosion of structural materials, research of material properties and welding, research of fluoride fluid properties, measuring of thermo-hydraulic properties of molten salt fluoride fluids, heat transfer and hydraulics, development and tests of some plant components (steam generators, heat exchangers, pumps, valves) and other engineering issues. Two electrolyzers have been manufactured for the research of fuel/coolant fluoride salts mixture purification. One for the production of hydrogen fluoride, and the other for the research of salts purification. (author)

  1. Fluoridated salt for caries prevention and control - a 2-year field study in a disadvantaged community

    DEFF Research Database (Denmark)

    Wennhall, Inger; Hajem, Samara; Ilros, Susanna

    2014-01-01

    BACKGROUND: Salt fluoridation is considered a cost-effective community strategy for reducing caries. AIM: To evaluate the effect of school-based and domestic distribution of F-salt to schoolchildren residing in a disadvantaged community. DESIGN: Seven hundred and thirty-three schoolchildren (12...

  2. Assessment of the Use of Nitrogen Trifluoride for Purifying Coolant and Heat Transfer Salts in the Fluoride Salt-Cooled High-Temperature Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Scheele, Randall D.; Casella, Andrew M.

    2010-09-28

    This report provides an assessment of the use of nitrogen trifluoride for removing oxide and water-caused contaminants in the fluoride salts that will be used as coolants in a molten salt cooled reactor.

  3. Risk Assessment Study of Fluoride Salts: Probability-Impact Matrix of Renal and Hepatic Toxicity Markers.

    Science.gov (United States)

    Usuda, Kan; Ueno, Takaaki; Ito, Yuichi; Dote, Tomotaro; Yokoyama, Hirotaka; Kono, Koichi; Tamaki, Junko

    2016-09-01

    The present risk assessment study of fluoride salts was conducted by oral administration of three different doses of sodium and potassium fluorides (NaF, KF) and zinc fluoride tetrahydrate (ZnF2 •4H2O) to male Wistar rats. The rats were divided into control and nine experimental groups, to which oral injections of 0.5 mL distilled water and 0.5 mL of fluoride solutions, respectively, were given. The dosage of fluoride compounds was adjusted to contain 2.1 mg (low-dose group, LG), 4.3 mg (mid-dose group, MG), and 5.4 mg fluoride per 200 g rat body weight (high-dose group, HG) corresponding to 5, 10, and 12.5 % of LD50 values for NaF. The 24-h urine volume, N-acetyl-β-D-glucosaminidase (NAG) and creatinine clearance (Ccr) were measured as markers of possible acute renal impact. The levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were determined in serum samples as markers of acute hepatic impact. The levels of serum and urinary fluoride were determined to evaluate fluoride bioavailability. The results reveal that higher doses of NaF, KF, and ZnF2 induced renal damage as indicated by higher urinary NAG (p fluoride is a potential, dose-dependent risk factor of renal tubular damage.

  4. Mesocarbon microbead based graphite for spherical fuel element to inhibit the infiltration of liquid fluoride salt in molten salt reactor

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Yajuan, E-mail: yajuan.zhong@gmail.com [Center for Thorium Molten Salt Reactor System, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); CAS Key Laboratory of Carbon Materials, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China); Zhang, Junpeng [CAS Key Laboratory of Carbon Materials, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China); Lin, Jun, E-mail: linjun@sinap.ac.cn [Center for Thorium Molten Salt Reactor System, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Xu, Liujun [Center for Thorium Molten Salt Reactor System, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Feng; Xu, Hongxia; Chen, Yu; Jiang, Haitao; Li, Ziwei; Zhu, Zhiyong [Center for Thorium Molten Salt Reactor System, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Guo, Quangui [CAS Key Laboratory of Carbon Materials, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China)

    2017-07-15

    Mesocarbon microbeads (MCMB) and quasi-isostatic pressing method were used to prepare MCMB based graphite (MG) for spherical fuel element to inhibit the infiltration of liquid fluoride salt in molten salt reactor (MSR). Characteristics of mercury infiltration and molten salt infiltration in MG were investigated and compared with A3-3 (graphite for spherical fuel element in high temperature gas cooled reactor) to identify the infiltration behaviors. The results indicated that MG had a low porosity about 14%, and an average pore diameter of 96 nm. Fluoride salt occupation of A3-3 (average pore diameter was 760 nm) was 10 wt% under 6.5 atm, whereas salt gain did not infiltrate in MG even up to 6.5 atm. It demonstrated that MG could inhibit the infiltration of liquid fluoride salt effectively. Coefficient of thermal expansion (CTE) of MG lies in 6.01 × 10{sup −6} K{sup −1} (α{sub ∥}) and 6.15 × 10{sup −6} K{sup −1} (α{sub ⊥}) at the temperature range of 25–700 °C. The anisotropy factor of MG calculated by CTE maintained below 1.02, which could meet the requirement of the spherical fuel element (below 1.30). The constant isotropic property of MG is beneficial for the integrity and safety of the graphite used in the spherical fuel element for a MSR.

  5. Mesocarbon microbead based graphite for spherical fuel element to inhibit the infiltration of liquid fluoride salt in molten salt reactor

    International Nuclear Information System (INIS)

    Zhong, Yajuan; Zhang, Junpeng; Lin, Jun; Xu, Liujun; Zhang, Feng; Xu, Hongxia; Chen, Yu; Jiang, Haitao; Li, Ziwei; Zhu, Zhiyong; Guo, Quangui

    2017-01-01

    Mesocarbon microbeads (MCMB) and quasi-isostatic pressing method were used to prepare MCMB based graphite (MG) for spherical fuel element to inhibit the infiltration of liquid fluoride salt in molten salt reactor (MSR). Characteristics of mercury infiltration and molten salt infiltration in MG were investigated and compared with A3-3 (graphite for spherical fuel element in high temperature gas cooled reactor) to identify the infiltration behaviors. The results indicated that MG had a low porosity about 14%, and an average pore diameter of 96 nm. Fluoride salt occupation of A3-3 (average pore diameter was 760 nm) was 10 wt% under 6.5 atm, whereas salt gain did not infiltrate in MG even up to 6.5 atm. It demonstrated that MG could inhibit the infiltration of liquid fluoride salt effectively. Coefficient of thermal expansion (CTE) of MG lies in 6.01 × 10 −6 K −1 (α ∥ ) and 6.15 × 10 −6 K −1 (α ⊥ ) at the temperature range of 25–700 °C. The anisotropy factor of MG calculated by CTE maintained below 1.02, which could meet the requirement of the spherical fuel element (below 1.30). The constant isotropic property of MG is beneficial for the integrity and safety of the graphite used in the spherical fuel element for a MSR.

  6. Pilot-Scale Removal Of Fluoride From Legacy Plutonium Materials Using Vacuum Salt Distillation

    International Nuclear Information System (INIS)

    Pierce, R. A.; Pak, D. J.

    2012-01-01

    Between September 2009 and January 2011, the Savannah River National Laboratory (SRNL) and HB-Line designed, developed, tested, and successfully deployed a system for the distillation of chloride salts. In 2011, SRNL adapted the technology for the removal of fluoride from fluoride-bearing salts. The method involved an in situ reaction between potassium hydroxide (KOH) and the fluoride salt to yield potassium fluoride (KF) and the corresponding oxide. The KF and excess KOH can be distilled below 1000°C using vacuum salt distillation (VSD). The apparatus for vacuum distillation contains a zone heated by a furnace and a zone actively cooled using either recirculated water or compressed air. During a vacuum distillation operation, a sample boat containing the feed material is placed into the apparatus while it is cool, and the system is sealed. The system is evacuated using a vacuum pump. Once a sufficient vacuum is attaned, heating begins. Volatile salts distill from the heated zone to the cooled zone where they condense, leaving behind the non-volatile material in the feed boat. Studies discussed in this report were performed involving the use of non-radioactive simulants in small-scale and pilot-scale systems as well as radioactive testing of a small-scale system with plutonium-bearing materials. Aspects of interest include removable liner design considerations, boat materials, in-line moisture absorption, and salt deposition

  7. Electrolytic experiments of gadolinium and neodymium ions in the fluoride molten salt

    International Nuclear Information System (INIS)

    Sim, J. B.; Hwang, S. C.; Kim, W. H.; Kang, Y. H.; Lee, B. J.; Yoo, J. H.

    2002-01-01

    Electrolytic reductions of Gd 3+ and Nd 3+ ions were carried out to prepare bismuth alloys including Gd and Nd solutes using a molten liquid Bi cathode in the LiF-NaF-KF fluoride salt. It was considered that selective separation of Gd from bismuth alloy is possible by controlling the addition amount of an oxidation agent to a salt phase. Cyclic voltammetry measurements are useful tools not only for in-situ detection of solutes in salt phase in the course of back extraction experiments but also for elucidation of electrochemical reactions of Gd and Nd in the FLINAK molten salt

  8. Fluoride partitioning R and D programme for molten salt transmutation reactor systems in the Czech Republic

    International Nuclear Information System (INIS)

    Uhlir, J.; Priman, V.; Vanicek, J.

    2001-01-01

    The transmutation of spent nuclear fuel is considered a prospective alternative conception to the current conception based on the non-reprocessed spent fuel disposal into underground repository. The Czech research and development programme in the field of partitioning and transmutation is founded on the Molten Salt Transmutation Reactor system concept with fluoride salts based liquid fuel, the fuel cycle of which is grounded on pyrochemical / pyrometallurgical fluoride partitioning of spent fuel. The main research activities in the field of fluoride partitioning are oriented mainly towards technological research of Fluoride Volatility Method and laboratory research on electro-separation methods from fluoride melts media. The Czech national conception in the area of P and T research issues from the national power industry programme and from the Czech Power Company intentions of the extensive utilization of nuclear power in our country. The experimental R and D work is concentrated mainly in the Nuclear Research Institute Rez plc that plays a role of main nuclear research workplace for the Czech Power Company. (author)

  9. Metathesis synthesis and characterization of complex metal fluoride ...

    Indian Academy of Sciences (India)

    Administrator

    V MANIVANNAN*, P PARHI and JONATHAN W KRAMER. Department of Mechanical Engineering, Campus Delivery 1374, Colorado State University, Fort Collins,. CO 80523, USA. MS received 30 April 2008. Abstract. Metathesis synthesis of complex metal fluorides using mechanochemical activation has been reported.

  10. Protection of nuclear graphite toward fluoride molten salt by glassy carbon deposit

    International Nuclear Information System (INIS)

    Bernardet, V.; Gomes, S.; Delpeux, S.; Dubois, M.; Guerin, K.; Avignant, D.; Renaudin, G.; Duclaux, L.

    2009-01-01

    Molten salt reactor represents one of the promising future Generation IV nuclear reactors families where the fuel, a liquid molten fluoride salt, is circulating through the graphite reactor core. The interactions between nuclear graphite and fluoride molten salt and also the graphite surface protection were investigated in this paper by powder X-ray diffraction, micro-Raman spectroscopy and scanning electron microscopy coupled with X-ray microanalysis. Nuclear graphite discs were covered by two kinds of protection deposit: a glassy carbon coating and a double coating of pyrolitic carbon/glassy carbon. Different behaviours have been highlighted according to the presence and the nature of the coated protection film. Intercalation of molten salt between the graphite layers did not occur. Nevertheless the molten salt adhered more or less to the surface of the graphite disc, filled more or less the graphite surface porosity and perturbed more or less the graphite stacking order at the disc surface. The behaviour of unprotected graphite was far to be satisfactory after two days of immersion of graphite in molten salt at 500 deg. C. The best protection of the graphite disc surface, with the maximum of inertness towards molten salt, has been obtained with the double coating of pyrolitic carbon/glassy carbon

  11. Fluoride

    Science.gov (United States)

    Opalescence® ... Fluoride is used to prevent tooth decay. It is taken up by teeth and helps to strengthen ... and block the cavity-forming action of bacteria. Fluoride usually is prescribed for children and adults whose ...

  12. Selective Adsorption of Sodium Aluminum Fluoride Salts from Molten Aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Leonard S. Aubrey; Christine A. Boyle; Eddie M. Williams; David H. DeYoung; Dawid D. Smith; Feng Chi

    2007-08-16

    Aluminum is produced in electrolytic reduction cells where alumina feedstock is dissolved in molten cryolite (sodium aluminum fluoride) along with aluminum and calcium fluorides. The dissolved alumina is then reduced by electrolysis and the molten aluminum separates to the bottom of the cell. The reduction cell is periodically tapped to remove the molten aluminum. During the tapping process, some of the molten electrolyte (commonly referred as “bath” in the aluminum industry) is carried over with the molten aluminum and into the transfer crucible. The carryover of molten bath into the holding furnace can create significant operational problems in aluminum cast houses. Bath carryover can result in several problems. The most troublesome problem is sodium and calcium pickup in magnesium-bearing alloys. Magnesium alloying additions can result in Mg-Na and Mg-Ca exchange reactions with the molten bath, which results in the undesirable pickup of elemental sodium and calcium. This final report presents the findings of a project to evaluate removal of molten bath using a new and novel micro-porous filter media. The theory of selective adsorption or removal is based on interfacial surface energy differences of molten aluminum and bath on the micro-porous filter structure. This report describes the theory of the selective adsorption-filtration process, the development of suitable micro-porous filter media, and the operational results obtained with a micro-porous bed filtration system. The micro-porous filter media was found to very effectively remove molten sodium aluminum fluoride bath by the selective adsorption-filtration mechanism.

  13. Heat Transfer in Pebble-Bed Nuclear Reactor Cores Cooled by Fluoride Salts

    Science.gov (United States)

    Huddar, Lakshana Ravindranath

    With electricity demand predicted to rise by more than 50% within the next 20 years and a burgeoning world population requiring reliable emissions-free base-load electricity, can we design advanced nuclear reactors to help meet this challenge? At the University of California, Berkeley (UCB) Fluoride-salt-cooled High Temperature Reactors (FHR) are currently being investigated. FHRs are designed with better safety and economic characteristics than conventional light water reactors (LWR) currently in operation. These reactors operate at high temperature and low pressure making them more efficient and safer than LWRs. The pebble-bed FHR (PB-FHR) variant includes an annular nuclear reactor core that is filled with randomly packed pebble fuel. It is crucial to characterize the heat transfer within this unique geometry as this informs the safety limits of the reactor. The work presented in this dissertation focused on furthering the understanding of heat transfer in pebble-bed nuclear reactor cores using fluoride salts as a coolant. This was done through experimental, analytical and computational techniques. A complex nuclear system with a coolant that has never previously been in commercial use requires experimental data that can directly inform aspects of its design. It is important to isolate heat transfer phenomena in order to understand the underlying physics in the context of the PB-FHR, as well as to make decisions about further experimental work that needs to be done in support of developing the PB-FHR. Certain organic oils can simulate the heat transfer behaviour of the fluoride salt if relevant non-dimensional parameters are matched. The advantage of this method is that experiments can be done at a much lower temperature and at a smaller geometric scale compared to FHRs, thereby lowering costs. In this dissertation, experiments were designed and performed to collect data demonstrating similitude. The limitations of these experiments were also elucidated by

  14. Dynamic Reference Electrode development for redox potential measurements in fluoride molten salt at high temperature

    International Nuclear Information System (INIS)

    Durán-Klie, Gabriela; Rodrigues, Davide; Delpech, Sylvie

    2016-01-01

    Measurement of redox potential in fluoride media is a major problem due to the difficulty to design a reference electrode with high stability, high mechanical resistance and high accuracy. In the frame of molten salt reactor studies, a dynamic reference electrode (DRE) is developed to measure redox potential in fluoride molten salt at high temperature. DRE is based on the in-situ generation of a transient redox system. The choice of the redox couple corresponds to the cathodic limit of the molten salt considered. As a preliminary step, the demonstration of feasibility of generating a DRE was done in LiF-NaF-KF (46.5–11.5–42 mol%) media at 500 °C. In this salt, the reference redox system generated by coulometry at applied current is KF/K, metallic potassium being electrodeposited on a tungsten wire electrode. The validation of the DRE response and the experimental optimization parameters for DRE generation were realized by following the NiF 2 /Ni redox potential evolution as a function of NiF 2 concentration in the fused salt. The current value applied for DRE generation was optimized. It depends on the amount of metallic cations contained in the fused salt and which can be electrochemically reduced simultaneously during the DRE generation. The current corresponding to the DRE generation has to be 4 times greater than the current corresponding to the reduction of the other elements.

  15. Modeling an economic evaluation of a salt fluoridation program in Peru.

    Science.gov (United States)

    Mariño, Rodrigo J; Fajardo, Jorge; Arana, Ana; Garcia, Carlos; Pachas, Flor

    2011-01-01

    This article models the cost-effectiveness, from a societal viewpoint, of a dental caries prevention program using salt fluoridation for children 12 years of age, compared with non-intervention (or status quo) in Arequipa, Peru. Standard cost-effectiveness analysis methods were used. The costs associated with implementing and operating the salt-fluoridation program were identified and measured using 2009 prices. Health outcomes were measured as dental caries averted over a 6-year period. Clinical effectiveness data was taken from published data. Costs were measured as direct treatment costs, programs costs and costs of productivity losses as a result of dental treatments. The incremental cost-effectiveness ratio was calculated. A hypothetical population of 25,000 12-year-olds living in Arequipa, Peru was used in this analysis. Two-way sensitivity analyses were conducted over a range of values for key parameters. Our primary analysis estimated that if a dental caries prevention program using salt-fluoridation was available for 25,000 6-year-old children for 6 years, the net saving from a societal perspective would total S/. 11.95 [1 US$ = S/. (2009) 3.01] per diseased tooth averted when compared with the status quo group. That is, after 6 years, an investment of S/.0.32 per annum per child would result in a net saving of S/.11.95 per decayed/missing/filled teeth prevented. While the analysis has inherent limitations as a result of its reliance on a range of assumptions, the findings indicate that for the situations prevailing in Peru, there are significant health and economic benefits to be gained from the use of salt fluoridation.

  16. Process Heat Exchanger Options for Fluoride Salt High Temperature Reactor

    International Nuclear Information System (INIS)

    Sabharwall, Piyush; Kim, Eung Soo; McKellar, Michael; Anderson, Nolan

    2011-01-01

    The work reported herein is a significant intermediate step in reaching the final goal of commercial-scale deployment and usage of molten salt as the heat transport medium for process heat applications. The primary purpose of this study is to aid in the development and selection of the required heat exchanger for power production and process heat application, which would support large-scale deployment.

  17. Process Heat Exchanger Options for Fluoride Salt High Temperature Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Piyush Sabharwall; Eung Soo Kim; Michael McKellar; Nolan Anderson

    2011-04-01

    The work reported herein is a significant intermediate step in reaching the final goal of commercial-scale deployment and usage of molten salt as the heat transport medium for process heat applications. The primary purpose of this study is to aid in the development and selection of the required heat exchanger for power production and process heat application, which would support large-scale deployment.

  18. Comparison of molten chloride and fluoride salts potentialities for An/Ln separation by electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Laplace, A.; Peron, F.; Marrot, F.; Lacquement, J. [DRCP/SCPS/LPP - CEA/CEN Valrho - BP 17171 - 30207 Bagnols/Ceze (France)

    2008-07-01

    The objective of this paper is the comparison of molten fluoride and chloride salts potentialities for Am/Nd separation by electrodeposition on inert cathode, on a purely thermodynamic point of view. The molten LiF-CaF{sub 2} eutectic (77-23 mol.%, at 780 deg. C) was considered for this study. Cyclic voltammetry showed a one step Am(III)/Am reduction at a potential of {approx_equal}+0.5 V vs. Li{sup +}/Li. A potential difference of 290 mV between Am and Nd metallic deposition was estimated by square-wave voltammetry. This Am/Nd potential difference is more important than in molten chlorides (220 mV in the LiCl-KCl eutectic at 500 deg. C). Moreover in molten fluoride salt, the americium and neodymium (+II) oxidation state is not stable contrary to the molten chloride one where corrosion of deposited Am would be potential. However this larger potential difference in molten fluorides is quite balanced by the higher working temperature. (authors)

  19. Production and Release of ISOL Beams from Molten Fluoride Salt Targets

    CERN Document Server

    Mendonca, T M; Ghetta, V; Alibert, M; Heuer, D; Noah, E; Cimmino, S; Delonca, M; Gottberg, A; Kronberger, M; Ramos, J; Seiffert, C; Stora, T; CERN. Geneva. ATS Department

    2014-01-01

    In the framework of the Beta Beams study, a molten fluoride target has been proposed for the production of the required 1013 18Ne/s. The production and extraction of such rates are obtained on a circulating molten salt with proton beam energy beams at close to 1 MW power. As a most important step to validate the concept, a prototype has been designed and investigated at CERN-ISOLDE using a static target unit. The target material consisted of a binary fluoride system, NaF:LiF (39:61 % mol.), with melting point at 649ºC. The production of Ne beams has been monitored as a function of the target temperature and proton beam intensity. The prototype development and the results of the first online tests with 1.4 GeV proton beam are presented in this paper.

  20. The determination of UO2 and UF4 in fused fluoride salts

    International Nuclear Information System (INIS)

    Batiste, D.J.; Lee, D.A.

    1989-01-01

    The determination of uranium oxide solubilities in fused fluoride salts is important in the electrolytic preparation of uranium metal. This project was initiated to develop a method for the determination of UO 2 separately from UF 4 in UF 4 -CaF 2 -LiF fused salts. Previous methods used for the determination of UO 2 in fused fluoride salts involved inert gas fusions where oxygen was liberated as CO 2 , and hydrofluorination where oxygen was released as H 2 O; but the special equipment used for these procedures was no longer available. These methods assumed that all of the oxygen liberated was due to UO 2 and does not consider impurities from reagents and other oxygen sources that amount to a bias of approximately 0.3 wt %. This titrimetric method eliminates the bias by selectively extracting the UF 4 with a Na 2 EDTA-H 3 BO 3 solution. The remaining uranium oxide residue is treated and titrated gravimetrically to a potentiometric endpoint with NBS standard K 2 Cr 2 O 7 . An aliquot of the Na 2 EDTA-H 3 BO 3 extract is also titrated gravimetrically to a potentiometric endpoint, this uranium component is determined and calculated as UF 4 . 4 refs., 2 figs., 2 tabs

  1. Study of interaction of uranium, plutonium and rare earth fluorides with some metal oxides in fluoric salt melts

    International Nuclear Information System (INIS)

    Gorbunov, V.F.; Novoselov, G.P.; Ulanov, S.A.

    1976-01-01

    Interaction of plutonium, uranium, and rare-earth elements (REE) fluorides with aluminium and calcium oxides in melts of eutectic mixture LiF-NaF has been studied at 800 deg C by X-ray diffraction method. It has been shown that tetravalent uranium and plutonium are coprecipitated by oxides as a solid solution UO 2 -PuO 2 . Trivalent plutonium in fluorides melts in not precipitated in the presence of tetravalent uranium which can be used for their separation. REE are precipitated from a salt melt by calcium oxide and are not precipitated by aluminium oxide. Thus, aluminium oxide in a selective precipitator for uranium and plutonium in presence of REE. Addition of aluminium fluoride retains trivalent plutonium and REE in a salt melt in presence of Ca and Al oxides. The mechanism of interacting plutonium and REE trifluorides with metal oxides in fluoride melts has been considered

  2. Nickel-plating for active metal dissolution resistance in molten fluoride salts

    Energy Technology Data Exchange (ETDEWEB)

    Olson, Luke [Department of Engineering Physics, 1500 Engineering Drive, University of Wisconsin, Madison, WI 53706 (United States); Sridharan, Kumar, E-mail: kumar@engr.wisc.edu [Department of Engineering Physics, 1500 Engineering Drive, University of Wisconsin, Madison, WI 53706 (United States); Anderson, Mark; Allen, Todd [Department of Engineering Physics, 1500 Engineering Drive, University of Wisconsin, Madison, WI 53706 (United States)

    2011-04-15

    Ni electroplating of Incoloy-800H was investigated with the goal of mitigating Cr dissolution from this alloy into molten 46.5%LiF-11.5%NaF-42%KF eutectic salt, commonly referred to as FLiNaK. Tests were conducted in graphite crucibles at a molten salt temperature of 850 deg. C. The crucible material graphite accelerates the corrosion process due to the large activity difference between the graphite and the alloy. For the purposes of providing a baseline for this study, un-plated Incoloy-800H and a nearly pure Ni-alloy, Ni-201 were also tested. Results indicate that Ni-plating has the potential to significantly improve the corrosion resistance of Incoloy-800H in molten fluoride salts. Diffusion of Cr from the alloy through the Ni-plating does occur and if the Ni-plating is thin enough this Cr eventually dissolves into the molten salt. The post-corrosion test microstructure of the Ni-plating, particularly void formation was also observed to depend on the plating thickness. Diffusion anneals in a helium environment of Ni-plated Incoloy-800H and an Fe-Ni-Cr model alloy were also investigated to understand Cr diffusion through the Ni-plating. Further enhancements in the efficacy of the Ni-plating as a protective barrier against Cr dissolution from the alloy into molten fluoride salts can be achieved by thermally forming a Cr{sub 2}O{sub 3} barrier film on the surface of the alloy prior to Ni electroplating.

  3. Development of fluoride reprocessing technology for molten salt transmutation reactor systems in the Czech Republic

    International Nuclear Information System (INIS)

    Uhlir, J.; Hosnedl, P.; Matal, O.

    2000-01-01

    At present, the transmutation of spent nuclear fuel is considered a prospective alternative conception with respect to the current conception based on the non-reprocessed spent fuel disposal into a deep geological repository. The Czech research and development programme in the area of partitioning is directed primarily on the development of the fuel cycle technology for the accelerator - driven subcritical reactor with a liquid fuel based on fluoride melts. The final objective of the research programme is the development of pyrochemical technologies suitable for a continuous or semi-continuous separation process which would allow practically perfect utilization of the transmutation potentialities of the reactor system. The present research is directed particularly on the development of suitable fluoride separation methods the target of which is the removal of the uranium component from spent nuclear fuel and on the research of the electro-separation procedures and further on the development of appropriate construction materials and equipment for the technology of fluoride salt melts. (authors)

  4. Fluoride Salt-Cooled High-Temperature Reactor Technology Development and Demonstration Roadmap

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, David Eugene [ORNL; Flanagan, George F [ORNL; Mays, Gary T [ORNL; Pointer, William David [ORNL; Robb, Kevin R [ORNL; Yoder Jr, Graydon L [ORNL

    2013-11-01

    Fluoride salt-cooled High-temperature Reactors (FHRs) are an emerging reactor class with potentially advantageous performance characteristics, and fully passive safety. This roadmap describes the principal remaining FHR technology challenges and the development path needed to address the challenges. This roadmap also provides an integrated overview of the current status of the broad set of technologies necessary to design, evaluate, license, construct, operate, and maintain FHRs. First-generation FHRs will not require any technology breakthroughs, but do require significant concept development, system integration, and technology maturation. FHRs are currently entering early phase engineering development. As such, this roadmap is not as technically detailed or specific as would be the case for a more mature reactor class. The higher cost of fuel and coolant, the lack of an approved licensing framework, the lack of qualified, salt-compatible structural materials, and the potential for tritium release into the environment are the most obvious issues that remain to be resolved.

  5. Measurement of europium (III)/europium (II) couple in fluoride molten salt for redox control in a molten salt reactor concept

    Science.gov (United States)

    Guo, Shaoqiang; Shay, Nikolas; Wang, Yafei; Zhou, Wentao; Zhang, Jinsuo

    2017-12-01

    The fluoride molten salt such as FLiNaK and FLiBe is one of the coolant candidates for the next generation nuclear reactor concepts, for example, the fluoride salt cooled high temperature reactor (FHR). For mitigating corrosion of structural materials in molten fluoride salt, the redox condition of the salts needs to be monitored and controlled. This study investigates the feasibility of applying the Eu3+/Eu2+ couple for redox control. Cyclic voltammetry measurements of the Eu3+/Eu2+ couple were able to obtain the concentrations ratio of Eu3+/Eu2+ in the melt. Additionally, the formal standard potential of Eu3+/Eu2+ was characterized over the FHR's operating temperatures allowing for the application of the Nernst equation to establish a Eu3+/Eu2+ concentration ratio below 0.05 to prevent corrosion of candidate structural materials. A platinum quasi-reference electrode with potential calibrated by potassium reduction potential is shown as reliable for the redox potential measurement. These results show that the Eu3+/Eu2+ couple is a feasible redox buffering agent to control the redox condition in molten fluoride salts.

  6. Improving molten fluoride salt and Xe135 barrier property of nuclear graphite by phenolic resin impregnation process

    Science.gov (United States)

    He, Zhao; Lian, Pengfei; Song, Yan; Liu, Zhanjun; Song, Jinliang; Zhang, Junpeng; Feng, Jing; Yan, Xi; Guo, Quangui

    2018-02-01

    A densification process has been conducted on isostatic graphite (IG-110, TOYO TANSO CO., Ltd., Japan) by impregnating phenolic resin to get the densified isostatic graphite (D-IG-110) with pore diameter of nearly 11 nm specifically for molten salt reactor application. The microstructure, mechanical, thermophysical and other properties of graphite were systematically investigated and compared before and after the densification process. The molten fluoride salt and Xe135 penetration in the graphite were evaluated in a high-pressure reactor and a vacuum device, respectively. Results indicated that D-IG-110 exhibited improved properties including infiltration resistance to molten fluoride salt and Xe135 as compared to IG-110 due to its low porosity of 2.8%, the average pore diameter of 11 nm and even smaller open pores on the surface of the graphite. The fluoride salt infiltration amount of IG-110 was 13.5 wt% under 1.5 atm and tended to be saturated under 3 atm with the fluoride salt occupation of 14.8 wt%. As to the D-IG-110, no salts could be detected even up to 10 atm attempted loading. The helium diffusion coefficient of D-IG-110 was 6.92 × 10-8 cm2/s, significantly less than 1.21 × 10-2 cm2/s of IG-110. If these as-produced properties for impregnated D-IG-110 could be retained during MSR operation, the material could prove effective at inhibiting molten fluoride salt and Xe135 inventories in the graphite.

  7. The United States fluoride-salt-cooled high-temperature reactor program

    International Nuclear Information System (INIS)

    Holcomb, David E.

    2013-01-01

    The United States is pursuing the development of fluoride-salt-cooled high-temperature reactors (FHRs) through the Department of Energy's Office of Nuclear Energy (DOE-NE). FHRs, by definition, feature low-pressure liquid fluoride salt cooling, coated-particle fuel, a high-temperature power cycle, and fully passive decay heat rejection. FHRs, in principle, have the potential to economically generate large amounts of electricity while maintaining full passive safety. FHRs, however, remain a longer-term power production option. A principal development focus is, thus, on shortening, to the extent possible, the overall development time by focusing initial efforts on the longest lead-time issues. While FHRs represent a distinct reactor class, they inherit desirable attributes from other thermal power plants whose characteristics can be studied to provide general guidance on plant configuration, anticipated performance, and costs. Molten salt reactors provide experience on the materials, procedures, and components necessary to use liquid fluoride salts. Liquid-metal reactors provide design experience on using low-pressure liquid coolants, passive decay heat removal, and hot refueling. High-temperature gas-cooled reactors provide experience with coated-particle fuel and graphite components. Light-water reactors show the potential of transparent, high-heat-capacity coolants with low chemical reactivity. The FHR development efforts include both reactor concept and technology developments and are being broadly pursued. Oak Ridge National Laboratory (ORNL) provides technical leadership to the effort and is performing concept development on both a large base-load-type FHR as well as a small modular reactor (SMR) in addition to performing a broad scope of technology developments. Idaho National Laboratory (INL) is providing coated-particle fuel irradiation testing as well as developing high-temperature steam generator technology. The Massachusetts Institute of Technology (MIT

  8. An experimental test facility to support development of the fluoride-salt-cooled high-temperature reactor

    International Nuclear Information System (INIS)

    Yoder, Graydon L.; Aaron, Adam; Cunningham, Burns; Fugate, David; Holcomb, David; Kisner, Roger; Peretz, Fred; Robb, Kevin; Wilgen, John; Wilson, Dane

    2014-01-01

    Highlights: • • A forced convection test loop using FLiNaK salt was constructed to support development of the FHR. • The loop is built of alloy 600, and operating conditions are prototypic of expected FHR operation. • The initial test article is designed to study pebble bed heat transfer cooled by FLiNaK salt. • The test facility includes silicon carbide test components as salt boundaries. • Salt testing with silicon carbide and alloy 600 confirmed acceptable loop component lifetime. - Abstract: The need for high-temperature (greater than 600 °C) energy transport systems is significantly increasing as the world strives to improve energy efficiency and develop alternatives to petroleum-based fuels. Liquid fluoride salts are one of the few energy transport fluids that have the capability of operating at high temperatures in combination with low system pressures. The fluoride-salt-cooled high-temperature reactor design uses fluoride salt to remove core heat and interface with a power conversion system. Although a significant amount of experimentation has been performed with these salts, specific aspects of this reactor concept will require experimental confirmation during the development process. The experimental facility described here has been constructed to support the development of the fluoride-salt-cooled high-temperature reactor concept. The facility is capable of operating at up to 700 °C and incorporates a centrifugal pump to circulate FLiNaK salt through a removable test section. A unique inductive heating technique is used to apply heat to the test section, allowing heat transfer testing to be performed. An air-cooled heat exchanger removes added heat. Supporting loop infrastructure includes a pressure control system, a trace heating system, and a complement of instrumentation to measure salt flow, temperatures, and pressures around the loop. The initial experiment is aimed at measuring fluoride-salt heat transfer inside a heated pebble bed

  9. Corrosion resistant structural materials for use in lithium fluoride molten salts and thermonuclear device using it

    International Nuclear Information System (INIS)

    Kawamura, Kazutaka; Takagi, Ryuzo.

    1987-01-01

    Purpose: To provide blanket materials for thermo nuclear devices and structural materials for containers with less MHD effect and good heat exchanging efficiency. Constitution: LiF-PbF 2 is used as the liquid blanket material for moderating the MHD effect. That is, the lithium compound, in the form of a fluoride, can be made easily liquefiable being and PbF 2 is added for lowering the melting point. The reason of using the fluoride is that fluorine material is less activated by the adsorption of neutrons. Copper, phosphor bronze, nickel or nickel-based alloy, e.g., Monel metal is used as corrosion resistant structural material to LiF-PbF 2 molten salts. Use of copper as the low activating structural material can provide an excellent effect also in view of the maintenance and, further, a series of processes for purifying, separating injecting and recoverying tritium can be conducted safely and stationarily without contaminating the circumferences. (Kamimura, M.)

  10. Preparation of pyrolytic carbon coating on graphite for inhibiting liquid fluoride salt and Xe135 penetration for molten salt breeder reactor

    International Nuclear Information System (INIS)

    Song, Jinliang; Zhao, Yanling; He, Xiujie; Zhang, Baoliang; Xu, Li; He, Zhoutong; Zhang, DongSheng; Gao, Lina; Xia, Huihao; Zhou, Xingtai; Huai, Ping; Bai, Shuo

    2015-01-01

    Highlights: • Rough laminar pyrolytic carbon coating (RLPyC) is prepared by a fixed-bed method. • The salt-infiltration into IG-110 is 13.5%, less than 0.01% of RLPyC under 1.5 atm. • The helium diffusion coefficient of RLPyC coated graphite is 2.16 × 10 −8 cm 2 /s. • The coated graphite can inhibit the liquid fluoride salt and Xe 135 penetration. - Abstract: A fixed-bed deposition method was used to prepare rough laminar pyrolytic carbon coating (RLPyC) on graphite for inhibiting liquid fluoride salt and Xe 135 penetration during use in molten salt breeder reactor. The RLPyC coating possessed a graphitization degree of 44% and had good contact with graphite substrate. A high-pressure reactor was constructed to evaluate the molten salt infiltration in the isostatic graphite (IG-110, TOYO TANSO CO., LTD.) and RLPyC coated graphite under 1.01, 1.52, 3.04, 5.07 and 10.13 × 10 5 Pa for 12 h. Mercury injection and molten-salt infiltration experiments indicated the porosity and the salt-infiltration amount of 18.4% and 13.5 wt% under 1.52 × 10 5 Pa of IG-110, which was much less than 1.2% and 0.06 wt% under 10.13 × 10 5 Pa of the RLPyC, respectively. A vacuum device was constructed to evaluate the Xe 135 penetration in the graphite. The helium diffusion coefficient of RLPyC coated graphite was 2.16 × 10 −12 m 2 /s, much less than 1.21 × 10 −6 m 2 /s of the graphite. Thermal cycle experiment indicated the coatings possessed excellent thermal stability. The coated graphite could effectively inhibit the liquid fluoride salt and Xe 135 penetration

  11. Investigating thermal-hydraulic characteristic of molten fluoride salt in a circular pipe using a CFD methodology

    International Nuclear Information System (INIS)

    Chi Chenwei; Ferng Yuhming; Pei Baushei; Liang Jenqhorng

    2011-01-01

    In recent years, the molten salt reactor (MSR) has attracted increasing attention and become one of the most important 'Generation IV reactor' designs. In particular, the fact that molten fluoride salts are utilized as liquid fuel and coolant constitutes the main feature of the reactor. Furthermore, since the molten fluoride salt has a high Prandtl number and contains quite different behaviors to those of ordinary water and gas, an in-depth investigation of molten fluoride salt is thus highly demanded. Hence, it is the central objective of this study to examine the thermal-hydraulic characteristics of molten salt especially for the optimal design of reactor core and its safety operation. In this study, the dependence of pressure drop, Nusselt number and entrance length on the inlet Reynolds number for a molten fluoride salt (LiF(46.5)-NaF(11.5)-KF(42)) are computed using a comprehensive computational fluid dynamics (CFD) methodology. The methodology employs the continuity equation, momentum equation, energy equation, and standard k - ε turbulence model to conduct fluid dynamics simulation. For simplicity, the geometry employed in this study is a circular tube. The simulated results indicated that the pressure drop and Nusselt number and entrance length increase as the inlet Reynolds number increases. And the computed pressure drop corresponds well to theoretical value. It is also given a new correlation of computed entrance length in this paper. In addition, two well-known Nusselt number correlations such as, Hausen, Gnielinski, are employed to make comparisons with the computed results. It is also found that the computed Nusselt numbers overestimate the Hausen ones in the high Reynolds number region. However, the computed Nusselt numbers correspond well to the Gnielinski ones in all the Reynolds numbers region. Also notice that an experimental setup is currently in progress in order to validate the present CFD simulation. (author)

  12. Molecular Fluoride-Bridged 3d-4f Complexes and Their Magnetic Properties

    DEFF Research Database (Denmark)

    Pedersen, K. S.; Bendix, J.

    2016-01-01

    trifluorides with very high lattice enthalpies, building block approaches are not limited to robust systems and use of labile transition metal fluoride complexes has met with unexpected success. The physical properties of fluoride-bridged 3d-4f systems are crucially dependent on coordination geometries, which...... be utilized efficiently in tailored synthesis of polynuclear complexes and extended structures. In particular, the strong affinity of the lanthanides for fluoride makes it a good choice for directed synthesis of mixed lanthanide-transition metal complexes. Despite the competition from formation of lanthanide...

  13. An Analysis of Testing Requirements for Fluoride Salt Cooled High Temperature Reactor Components

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, David Eugene [ORNL; Cetiner, Sacit M [ORNL; Flanagan, George F [ORNL; Peretz, Fred J [ORNL; Yoder Jr, Graydon L [ORNL

    2009-11-01

    This report provides guidance on the component testing necessary during the next phase of fluoride salt-cooled high temperature reactor (FHR) development. In particular, the report identifies and describes the reactor component performance and reliability requirements, provides an overview of what information is necessary to provide assurance that components will adequately achieve the requirements, and then provides guidance on how the required performance information can efficiently be obtained. The report includes a system description of a representative test scale FHR reactor. The reactor parameters presented in this report should only be considered as placeholder values until an FHR test scale reactor design is completed. The report focus is bounded at the interface between and the reactor primary coolant salt and the fuel and the gas supply and return to the Brayton cycle power conversion system. The analysis is limited to component level testing and does not address system level testing issues. Further, the report is oriented as a bottom-up testing requirements analysis as opposed to a having a top-down facility description focus.

  14. INTERACTION OF FLUORIDE COMPLEXES DERIVED FROM GLASS-IONOMER CEMENTS WITH HYDROXYAPATITE

    Directory of Open Access Journals (Sweden)

    Lewis S. M.

    2013-09-01

    Full Text Available A study has been undertaken of the interaction of complexed fluoride extracted from glass-ionomer dental cements with synthetic hydroxyapatite powder. Extracts were prepared from two commercial glass-ionomers (Fuji IX and ChemFlex under both neutral and acidic conditions. They were analysed by ICP-OES and by fluoride-ion selective electrode with and without added TISAB to decomplex the fluoride. The pH of the acid extracts was 4, conditions under which fluoride complexes with protons as HF or HF2-, it also complexes with aluminium, which was found to be present in higher amounts in the acid extracts. Fluoride was found to be almost completely complexed in acid extracts, but not in neutral extracts, which contained free fluoride ions. Exposure of these extracts to synthetic hydroxyapatite powder showed that fluoride was taken up rapidly (within 5 minutes, whether or not it was complexed. SEM (EDAX study of recovered hydroxyapatite showed only minute traces of aluminium taken up under all conditions. This showed that aluminium interacts hardly at all with hydroxyapatite, and hence is probably not involved in the remineralisation process.

  15. Determination of the stability constants of a number of metal fluoride complexes and their rates of formation

    International Nuclear Information System (INIS)

    Hammer, R.R.

    1979-08-01

    The stability constants of the fluoride complexes of Al +3 , H 3 BO 3 , Cr +3 , Cr +6 , Fe +3 , Gd +3 , Nb +5 , UO 2 +2 , and Zr +4 were determined in 0.96 and 2.88 M HNO 3 solutions in the temperature range 25 to 60 0 C with a fluoride specific ion electrode. These data can be used to calculate the concentration of chemical species in solution and will be used to correlate solution properties with solution composition. The solubilities of some fluoride precipitates were also measured in nitric acid solutions. The rates of formation of the fluoborates, aluminum fluoride, and zirconium fluoride complexes were measured with a fluoride specific ion electrode at 25, 35, and 45 0 C. The rates of formation of all complexes, except BF 4 - , AlF +2 , and a fluoride complex with aluminum containing more than three fluorides associated with it, were too fast to measure with the instrumentation used

  16. Sustainability of thorium-uranium in pebble-bed fluoride salt-cooled high temperature reactor

    International Nuclear Information System (INIS)

    Zhu, G.; Zou, Y.; Xu, H.

    2016-01-01

    Sustainability of thorium fuel in a Pebble-Bed Fluoride salt-cooled High temperature Reactor (PBFHR) is investigated to find the feasible region of high discharge burnup and negative Flibe (2LiF-BeF_2) salt Temperature Reactivity Coefficient (TRC). Dispersion fuel or pellet fuel with SiC cladding and SiC matrix is used to replace the tri-structural-isotropic (TRISO) coated particle system for increasing fuel loading and decreasing excessive moderation. To analyze the neutronic characteristics, an equilibrium calculation method of thorium fuel self-sustainability is developed. We have compared two refueling schemes (mixing flow pattern and directional flow pattern) and two kinds of reflector materials (SiC and graphite). This method found that the feasible region of breeding and negative Flibe TRC is between 20 vol% and 62 vol% fuel loading in the fuel. A discharge burnup could be achieved up to about 200 MWd/kgHM. The case with directional flow pattern and SiC reflector showed superior burnup characteristics but the worst radial power peak factor, while the case with mixing flow pattern and SiC reflector, which was the best tradeoff between discharge burnup and radial power peak factor, could provide burnup of 140 MWd/kgHM and about 1.4 radial power peak factor with 50 vol% dispersion fuel. In addition, Flibe salt displays good neutron properties as a coolant of quasi-fast reactors due to the strong "9Be(n,2n) reaction and low neutron absorption of "6Li (even at 1000 ppm) in fast spectrum. Preliminary thermal hydraulic calculation shows a good safety margin. The greatest challenge of this reactor may be the decades irradiation time of the pebble fuel. (A.C)

  17. Fluoride and Oral Health.

    Science.gov (United States)

    O'Mullane, D M; Baez, R J; Jones, S; Lennon, M A; Petersen, P E; Rugg-Gunn, A J; Whelton, H; Whitford, G M

    2016-06-01

    The discovery during the first half of the 20th century of the link between natural fluoride, adjusted fluoride levels in drinking water and reduced dental caries prevalence proved to be a stimulus for worldwide on-going research into the role of fluoride in improving oral health. Epidemiological studies of fluoridation programmes have confirmed their safety and their effectiveness in controlling dental caries. Major advances in our knowledge of how fluoride impacts the caries process have led to the development, assessment of effectiveness and promotion of other fluoride vehicles including salt, milk, tablets, toothpaste, gels and varnishes. In 1993, the World Health Organization convened an Expert Committee to provide authoritative information on the role of fluorides in the promotion of oral health throughout the world (WHO TRS 846, 1994). This present publication is a revision of the original 1994 document, again using the expertise of researchers from the extensive fields of knowledge required to successfully implement complex interventions such as the use of fluorides to improve dental and oral health. Financial support for research into the development of these new fluoride strategies has come from many sources including government health departments as well as international and national grant agencies. In addition, the unique role which industry has played in the development, formulation, assessment of effectiveness and promotion of the various fluoride vehicles and strategies is noteworthy. This updated version of 'Fluoride and Oral Health' has adopted an evidence-based approach to its commentary on the different fluoride vehicles and strategies and also to its recommendations. In this regard, full account is taken of the many recent systematic reviews published in peer reviewed literature.

  18. Vortex Diode Analysis and Testing for Fluoride Salt-Cooled High-Temperature Reactors

    International Nuclear Information System (INIS)

    Yoder, Graydon L. Jr.; Elkassabgi, Yousri M.; De Leon, Gerardo I.; Fetterly, Caitlin N.; Ramos, Jorge A.; Cunningham, Richard Burns

    2012-01-01

    Fluidic diodes are presently being considered for use in several fluoride salt-cooled high-temperature reactor designs. A fluidic diode is a passive device that acts as a leaky check valve. These devices are installed in emergency heat removal systems that are designed to passively remove reactor decay heat using natural circulation. The direct reactor auxiliary cooling system (DRACS) uses DRACS salt-to-salt heat exchangers (DHXs) that operate in a path parallel to the core flow. Because of this geometry, under normal operating conditions some flow bypasses the core and flows through the DHX. A flow diode, operating in reverse direction, is-used to minimize this flow when the primary coolant pumps are in operation, while allowing forward flow through the DHX under natural circulation conditions. The DRACSs reject the core decay heat to the environment under loss-of-flow accident conditions and as such are a reactor safety feature. Fluidic diodes have not previously been used in an operating reactor system, and therefore their characteristics must be quantified to ensure successful operation. This report parametrically examines multiple design parameters of a vortex-type fluidic diode to determine the size of diode needed to reject a particular amount of decay heat. Additional calculations were performed to size a scaled diode that could be tested in the Oak Ridge National Laboratory Liquid Salt Flow Loop. These parametric studies have shown that a 152.4 mm diode could be used as a test article in that facility. A design for this diode is developed, and changes to the loop that will be necessary to test the diode are discussed. Initial testing of a scaled flow diode has been carried out in a water loop. The 150 mm diode design discussed above was modified to improve performance, and the final design tested was a 171.45 mm diameter vortex diode. The results of this testing indicate that diodicities of about 20 can be obtained for diodes of this size. Experimental

  19. Supramolecular Complexes Formed in Systems Bile Salt-Bilirubin-Silica

    Science.gov (United States)

    Vlasova, N. N.; Severinovskaya, O. V.; Golovkova, L. P.

    The formation of supramolecular complexes between bilirubin and primary micelles of bile salts has been studied. The association constants of bile salts and binding of bilirubin with these associates have been determined. The adsorption of bilirubin and bile salts from individual and mixed aqueous solutions onto hydrophobic silica surfaces has been investigated. The interaction of bilirubin with primary bile salt micelles and the strong retention in mixed micelles, which are supramolecular complexes, result in the adsorption of bilirubin in free state only.

  20. Identification and evaluation of alternatives for the disposition of fluoride fuel and flush salts from the molten salt reactor experiment at Oak Ridge National Laboratory, Oak Ridge, Tennessee

    International Nuclear Information System (INIS)

    1996-01-01

    This document presents an initial identification and evaluation of the alternatives for disposition of the fluoride fuel and flush salts stored in the drain tanks at the Molten Salt Reactor Experiment (MSRE) at Oak Ridge National Laboratory (ORNL). It will serve as a resource for the U.S. Department of Energy contractor preparing the feasibility study for this activity under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA). This document will also facilitate further discussion on the range of credible alternatives, and the relative merits of alternatives, throughout the time that a final alternative is selected under the CERCLA process

  1. Preparation of Ti3C2 and Ti2C MXenes by fluoride salts etching and methane adsorptive properties

    Science.gov (United States)

    Liu, Fanfan; Zhou, Aiguo; Chen, Jinfeng; Jia, Jin; Zhou, Weijia; Wang, Libo; Hu, Qianku

    2017-09-01

    Here we reported the preparation of Ti3C2 MXene and Ti2C MXene by etching Ti3AlC2 and Ti2AlC with various fluoride salts in hydrochloric acid (HCl), including lithium fluoride (LiF), sodium fluoride (NaF), potassium fluoride (KF), and ammonium fluoride (NH4F). As-prepared Ti2C was further delaminated by urea, dimethylsulfoxide or ammonium hydroxide. Based on theoretical calculation and XPS results, the type of positive ions (Li+, Na+, K+, or NH4+) in etchant solution affect the surface structure of prepared MXene, which, in turn, affects the methane adsorption properties of MXene. The highest methane adsorption capacity is 8.5 cm3/g for Ti3C2 and 11.6 cm3/g for Ti2C. MXenes made from LiF and NH4F can absorb methane under high pressure and can keep methane under normal pressure, these MXenes may have important application on capturing methane or other hazardous gas molecules. MXenes made from NaF and KF can absorb methane under high pressure and release methane under low pressure. They can have important application in the adsorb storage of nature gas.

  2. Application Of Vacuum Salt Distillation Technology For The Removal Of Fluoride And Chloride From Legacy Fissile Materials

    International Nuclear Information System (INIS)

    Pierce, R.; Peters, T.

    2011-01-01

    Between September 2009 and January 2011, the Savannah River National Laboratory (SRNL) and the Savannah River Site (SRS) HB-Line Facility designed, developed, tested, and successfully deployed a production-scale system for the distillation of sodium chloride (NaCl) and potassium chloride (KCl) from plutonium oxide (PuO 2 ). Subsequent efforts adapted the vacuum salt distillation (VSD) technology for the removal of chloride and fluoride from less-volatile halide salts at the same process temperature and vacuum. Calcium chloride (CaCl 2 ), calcium fluoride (CaF 2 ), and plutonium fluoride (PuF 3 ) were of particular concern. To enable the use of the same operating conditions for the distillation process, SRNL employed in situ exchange reactions to convert the less-volatile halide salts to compounds that facilitated the distillation of halide without removal of plutonium. SRNL demonstrated the removal of halide from CaCl 2 , CaF 2 and PuF 3 below 1000 C using VSD technology.

  3. Preliminary Demonstration Reactor Point Design for the Fluoride Salt-Cooled High-Temperature Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Qualls, A. L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Betzler, Benjamin R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Brown, Nicholas R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Carbajo, Juan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Greenwood, Michael Scott [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hale, Richard Edward [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Harrison, Thomas J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Powers, Jeffrey J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Robb, Kevin R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Terrell, Jerry W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-12-01

    Development of the Fluoride Salt-Cooled High-Temperature Reactor (FHR) Demonstration Reactor (DR) is a necessary intermediate step to enable commercial FHR deployment through disruptive and rapid technology development and demonstration. The FHR DR will utilize known, mature technology to close remaining gaps to commercial viability. Lower risk technologies are included in the initial FHR DR design to ensure that the reactor can be built, licensed, and operated within an acceptable budget and schedule. These technologies include tristructural-isotropic (TRISO) particle fuel, replaceable core structural material, the use of that same material for the primary and intermediate loops, and tube-and-shell heat exchangers. This report provides an update on the development of the FHR DR. At this writing, the core neutronics and thermal hydraulics have been developed and analyzed. The mechanical design details are still under development and are described to their current level of fidelity. It is anticipated that the FHR DR can be operational within 10 years because of the use of low-risk, near-term technology options.

  4. Preliminary Demonstration Reactor Point Design for the Fluoride Salt-Cooled High-Temperature Reactor

    International Nuclear Information System (INIS)

    Qualls, A. L.; Betzler, Benjamin R.; Brown, Nicholas R.; Carbajo, Juan; Greenwood, Michael Scott; Hale, Richard Edward; Harrison, Thomas J.; Powers, Jeffrey J.; Robb, Kevin R.; Terrell, Jerry W.

    2015-01-01

    Development of the Fluoride Salt-Cooled High-Temperature Reactor (FHR) Demonstration Reactor (DR) is a necessary intermediate step to enable commercial FHR deployment through disruptive and rapid technology development and demonstration. The FHR DR will utilize known, mature technology to close remaining gaps to commercial viability. Lower risk technologies are included in the initial FHR DR design to ensure that the reactor can be built, licensed, and operated within an acceptable budget and schedule. These technologies include tristructural-isotropic (TRISO) particle fuel, replaceable core structural material, the use of that same material for the primary and intermediate loops, and tube-and-shell heat exchangers. This report provides an update on the development of the FHR DR. At this writing, the core neutronics and thermal hydraulics have been developed and analyzed. The mechanical design details are still under development and are described to their current level of fidelity. It is anticipated that the FHR DR can be operational within 10 years because of the use of low-risk, near-term technology options.

  5. Fluoride Salt-Cooled High-Temperature Demonstration Reactor Point Design

    Energy Technology Data Exchange (ETDEWEB)

    Qualls, A. L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Brown, Nicholas R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Betzler, Benjamin R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Carbajo, Juan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hale, Richard Edward [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Harrison, Thomas J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Powers, Jeffrey J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Robb, Kevin R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Terrell, Jerry W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wysocki, Aaron J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-02-01

    The fluoride salt-cooled high-temperature reactor (FHR) demonstration reactor (DR) is a concept for a salt-cooled reactor with 100 megawatts of thermal output (MWt). It would use tristructural-isotropic (TRISO) particle fuel within prismatic graphite blocks. FLiBe (2 LiF-BeF2) is the reference primary coolant. The FHR DR is designed to be small, simple, and affordable. Development of the FHR DR is a necessary intermediate step to enable near-term commercial FHRs. Lower risk technologies are purposely included in the initial FHR DR design to ensure that the reactor can be built, licensed, and operated within an acceptable budget and schedule. These technologies include TRISO particle fuel, replaceable core structural material, the use of that same material for the primary and intermediate loops, and tube-and-shell primary-to-intermediate heat exchangers. Several preconceptual and conceptual design efforts that have been conducted on FHR concepts bear a significant influence on the FHR DR design. Specific designs include the Oak Ridge National Laboratory (ORNL) advanced high-temperature reactor (AHTR) with 3400/1500 MWt/megawatts of electric output (MWe), as well as a 125 MWt small modular AHTR (SmAHTR) from ORNL. Other important examples are the Mk1 pebble bed FHR (PB-FHR) concept from the University of California, Berkeley (UCB), and an FHR test reactor design developed at the Massachusetts Institute of Technology (MIT). The MIT FHR test reactor is based on a prismatic fuel platform and is directly relevant to the present FHR DR design effort. These FHR concepts are based on reasonable assumptions for credible commercial prototypes. The FHR DR concept also directly benefits from the operating experience of the Molten Salt Reactor Experiment (MSRE), as well as the detailed design efforts for a large molten salt reactor concept and its breeder variant, the Molten Salt Breeder Reactor. The FHR DR technology is most representative of the 3400 MWt AHTR

  6. Preparation of pyrolytic carbon coating on graphite for inhibiting liquid fluoride salt and Xe{sup 135} penetration for molten salt breeder reactor

    Energy Technology Data Exchange (ETDEWEB)

    Song, Jinliang [Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Zhao, Yanling, E-mail: jlsong1982@yeah.net [School of Materials Science and Engineering, University of Jinan, Jinan 250022 (China); He, Xiujie; Zhang, Baoliang [Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Xu, Li [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); He, Zhoutong; Zhang, DongSheng; Gao, Lina; Xia, Huihao; Zhou, Xingtai; Huai, Ping [Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Bai, Shuo [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China)

    2015-01-15

    Highlights: • Rough laminar pyrolytic carbon coating (RLPyC) is prepared by a fixed-bed method. • The salt-infiltration into IG-110 is 13.5%, less than 0.01% of RLPyC under 1.5 atm. • The helium diffusion coefficient of RLPyC coated graphite is 2.16 × 10{sup −8} cm{sup 2}/s. • The coated graphite can inhibit the liquid fluoride salt and Xe{sup 135} penetration. - Abstract: A fixed-bed deposition method was used to prepare rough laminar pyrolytic carbon coating (RLPyC) on graphite for inhibiting liquid fluoride salt and Xe{sup 135} penetration during use in molten salt breeder reactor. The RLPyC coating possessed a graphitization degree of 44% and had good contact with graphite substrate. A high-pressure reactor was constructed to evaluate the molten salt infiltration in the isostatic graphite (IG-110, TOYO TANSO CO., LTD.) and RLPyC coated graphite under 1.01, 1.52, 3.04, 5.07 and 10.13 × 10{sup 5} Pa for 12 h. Mercury injection and molten-salt infiltration experiments indicated the porosity and the salt-infiltration amount of 18.4% and 13.5 wt% under 1.52 × 10{sup 5} Pa of IG-110, which was much less than 1.2% and 0.06 wt% under 10.13 × 10{sup 5} Pa of the RLPyC, respectively. A vacuum device was constructed to evaluate the Xe{sup 135} penetration in the graphite. The helium diffusion coefficient of RLPyC coated graphite was 2.16 × 10{sup −12} m{sup 2}/s, much less than 1.21 × 10{sup −6} m{sup 2}/s of the graphite. Thermal cycle experiment indicated the coatings possessed excellent thermal stability. The coated graphite could effectively inhibit the liquid fluoride salt and Xe{sup 135} penetration.

  7. A terminal fluoride ligand generates axial magnetic anisotropy in dysprosium complexes

    Energy Technology Data Exchange (ETDEWEB)

    Norel, Lucie [Department of Chemistry, University of California, Berkeley, CA (United States); Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, Rennes (France); Darago, Lucy E.; Chakarawet, Khetpakorn; Gonzalez, Miguel I.; Olshansky, Jacob H.; Long, Jeffrey R. [Department of Chemistry, University of California, Berkeley, CA (United States); Le Guennic, Boris; Rigaut, Stephane [Univ Rennes, CNRS, ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226, Rennes (France)

    2018-02-12

    The first dysprosium complexes with a terminal fluoride ligand are obtained as air-stable compounds. The strong, highly electrostatic dysprosium-fluoride bond generates a large axial crystal-field splitting of the J=15/2 ground state, as evidenced by high-resolution luminescence spectroscopy and correlated with the single-molecule magnet behavior through experimental magnetic susceptibility data and ab initio calculations. (copyright 2018 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Efficient SN2 fluorination of primary and secondary alkyl bromides by copper(I) fluoride complexes

    KAUST Repository

    Liu, Yanpin; Chen, Chaohuang; Li, Huaifeng; Huang, Kuo-Wei; Tan, Jianwei; Weng, Zhiqiang

    2013-01-01

    Copper(I) fluoride complexes ligated by phenanthroline derivatives have been synthesized and structurally characterized by X-ray crystallography. These complexes adopt as either ionic or neutral forms in the solid state, depending on the steric bulkiness of the substituent groups on the phenanthroline ligands. These complexes react with primary and secondary alkyl bromides to produce the corresponding alkyl fluorides in modest to good yields. This new method is compatible with a variety of important functional groups such as ether, thioether, amide, nitrile, methoxyl, hydroxyl, ketone, ester, and heterocycle moieties. © 2013 American Chemical Society.

  9. Efficient SN2 fluorination of primary and secondary alkyl bromides by copper(I) fluoride complexes

    KAUST Repository

    Liu, Yanpin

    2013-11-11

    Copper(I) fluoride complexes ligated by phenanthroline derivatives have been synthesized and structurally characterized by X-ray crystallography. These complexes adopt as either ionic or neutral forms in the solid state, depending on the steric bulkiness of the substituent groups on the phenanthroline ligands. These complexes react with primary and secondary alkyl bromides to produce the corresponding alkyl fluorides in modest to good yields. This new method is compatible with a variety of important functional groups such as ether, thioether, amide, nitrile, methoxyl, hydroxyl, ketone, ester, and heterocycle moieties. © 2013 American Chemical Society.

  10. Carbide Coatings for Nickel Alloys, Graphite and Carbon/Carbon Composites to be used in Fluoride Salt Valves

    Energy Technology Data Exchange (ETDEWEB)

    Nagle, Denis [Johns Hopkins Univ., Baltimore, MD (United States); Zhang, Dajie [Johns Hopkins Univ., Baltimore, MD (United States)

    2015-10-22

    The focus of this research was concerned with developing materials technology that supports the evolution of Generation IV Advanced High Temperature Reactor (AHTR) concepts. Specifically, we investigate refractory carbide coatings for 1) nickel alloys, and 2) commercial carbon-carbon composites (CCCs). Numerous compelling reasons have driven us to focus on carbon and carbide materials. First, unlike metals, the strength and modulus of CCCs increase with rising temperature. Secondly, graphite and carbon composites have been proven effective for resisting highly corrosive fluoride melts such as molten cryolite [Na₃AlF₆] at ~1000°C in aluminum reduction cells. Thirdly, graphite and carbide materials exhibit extraordinary radiation damage tolerance and stability up to 2000°C. Finally, carbides are thermodynamically more stable in liquid fluoride salt than the corresponding metals (i.e. Cr and Zr) found in nickel based alloys.

  11. Fluoride salts and container materials for thermal energy storage applications in the temperature range 973 - 1400 K

    Science.gov (United States)

    Misra, Ajay K.; Whittenberger, J. Daniel

    1987-01-01

    Multicomponent fluoride salt mixtures were characterized for use as latent heat of fusion heat storage materials in advanced solar dynamic space power systems with operating temperatures in the range of 973 to 1400 K. The melting points and eutectic composition for many systems with published phase diagrams were verified, and several new eutectic compositions were identified. Additionally, the heats of fusion of several binary and ternary eutectics and congruently melting intermediate compounds were measured by differential scanning calorimetry. The extent of corrosion of various metals by fluoride melts was estimated from thermodynamic considerations, and equilibrium conditions inside a containment vessel were calculated as functions of the initial moisture content of the salt and free volume above the molten salt. Preliminary experimental data on the corrosion of commercial, high-temperature alloys in LiF-19.5CaF2 and NaF-27CaF2-36MgF2 melts are presented and compared to the thermodynamic predictions.

  12. Fluoride salts and container materials for thermal energy storage applications in the temperature range 973 to 1400 K

    Science.gov (United States)

    Misra, Ajay K.; Whittenberger, J. Daniel

    1987-01-01

    Multicomponent fluoride salt mixtures were characterized for use as latent heat of fusion heat storage materials in advanced solar dynamic space power systems with operating temperatures in the range of 973 to 1400 K. The melting points and eutectic composition for many systems with published phase diagrams were verified, and several new eutectic compositions were identified. Additionally, the heats of fusion of several binary and ternary eutectics and congruently melting intermediate compounds were measured by differential scanning calorimetry. The extent of corrosion of various metals by fluoride melts was estimated from thermodynamic considerations, and equilibrium conditions inside a containment vessel were calculated as functions of the initial moisture content of the salt and free volume above the molten salt. Preliminary experimental data on the corrosion of commercial, high-temperature alloys in LiF-19.5CaF2 and NaF-27CaF2-36MgF2 melts are presented and compared to the thermodynamic predictions.

  13. Study of structure and chemical interactions in molten salt mixtures on the base of tantalum fluorides

    International Nuclear Information System (INIS)

    Agulyanskij, A.I.; Kirillov, S.A.; Prysyazhnyj, V.D.; AN Ukrainskoj SSR, Kiev. Inst. Obshchej i Neorganicheskoj Khimii)

    1980-01-01

    Using the method of IR-spectroscopy molten salt mixture containing K 2 TaF 7 , KF, KCl are investigated. It is detected that in the process of K 2 TaF 7 melting the TaF 6 - and TaF 7 2- ions are present in melt. When adding KF and KCl to the melt the equilibrium is shifted the direction of the TaF 7 2- and TaF 6 Cl 2- heptahaloid complexing respectively. In the melts with the composition close to the industrial electrolytes, containing K 2 TaF 7 , KF and KCl heptacoordinated tantalate ion is a prevailing one

  14. Study on the thorium-based breeder with molten fluoride salt blanket in the Nuclear Hot Spring - 5420

    International Nuclear Information System (INIS)

    Bing, X.; Yingzhong, L.

    2015-01-01

    Nuclear Hot Spring (NHS) is an innovative reactor type featured by pool-type molten-salt-cooled pebble-bed reactor core with the capability of natural circulation under full power operation. Except for the potential applications in power generation and high temperature process heat, thorium-based breeding is also a promising feature of the NHS. In order to take advantage of both the highly inherent safety and the on-line processing capability of fluid thorium-based fuels, a breeder design of NHS equipped with a blanket of molten salt with thorium fluoride outside the pebble-bed core is proposed in this work. For the purpose of keeping cleanness of the primary loop and blanket loop, both loops are isolated physically from each other, and the rapid on-line extraction of converted 233 Pa and 233 U is employed for the processing of blanket salt. The conversion ratio, defined as the ratio of converted 233 Pa and 233 U to the consumed fissile uranium in seed fuels, is investigated by varying the relevant parameters such as the circulation flux of blanket salt and the discharge burn-up of seed fuels. It is found that breeding can be achieved for the pure 233 U seed scheme with relatively low discharge burn-up and low blanket salt flux. However, the reprocessing for the HTGR fuels with TRISO particles has to be taken into account to ensure the breeding. (authors)

  15. Synthesis and characterization of binder-free Cr3C2 coatings on nickel-based alloys for molten fluoride salt corrosion resistance

    International Nuclear Information System (INIS)

    Brupbacher, Michael C.; Zhang, Dajie; Buchta, William M.; Graybeal, Mark L.; Rhim, Yo-Rhin; Nagle, Dennis C.; Spicer, James B.

    2015-01-01

    Under various conditions, chromium carbides appear to be relatively stable in the presence of molten fluoride salts and this suggests that their use in corrosion resistant coatings for fluoride salt environments could be beneficial. One method for producing these coatings is the carburization of sprayed Cr coatings using methane-containing gaseous precursors. This process has been investigated for the synthesis of binder-free chromium carbide coatings on nickel-based alloy substrates for molten fluoride salt corrosion resistance. The effects of the carburization process on coating microstructure have been characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) in conjunction with energy dispersive spectroscopy (EDS). Both plasma-sprayed and cold-sprayed Cr coatings have been successfully converted to Cr 3 C 2 , with the mechanism of conversion being strongly influenced by the initial porosity in the as-deposited coatings

  16. Displacement of Drugs From Cyclodextrin Complexes by Bile Salts

    DEFF Research Database (Denmark)

    Olesen, Niels Erik; Westh, Peter; Holm, Rene

    2016-01-01

    of drug from the cyclodextrin cavity by bile salts present in the small intestine. As bile salts in the intestine are present at concentrations above the critical micelle concentration, an understanding of the interaction between cyclodextrins and bile salts at such supramicellar concentrations (SMC......) is required for a better biopharmaceutical understanding of the release mechanism from orally dosed cyclodextrin complexes. To address this, experiments were conducted by isothermal titration calorimetry to determine how various b-cyclodextrins and bile salt interacts at SMC. Combined analysis of the current...... results and earlier data demonstrated that direct interactions between bile salt micelles and cyclodextrin were negligible. From this knowledge, an extended form of the UCD was suggested to describe the concentration of cyclodextrins to achieve full drug solubilization in the intestine where bile salts...

  17. Development of strong-sense validation benchmarks for the fluoride salt-cooled high-temperature reactor

    International Nuclear Information System (INIS)

    Blandford, E. D.

    2012-01-01

    The Fluoride salt-cooled High-temperature Reactor (FHR) is a class of reactor concepts currently under development for the U. S. Dept. of Energy. The FHR is defined as a Generation IV reactor that features low-pressure liquid fluoride salt cooling, coated-particle fuel, a high-temperature power cycle, and fully passive decay heat rejection. Recent experimental work using simulant fluids have been performed to demonstrate key 'proof of principle' FHR concepts and have helped inform the reactor design process. An important element of developing FHR technology is to sufficiently validate the predictive accuracy of the computer codes used to model system response. This paper presents a set of thermal-hydraulics experiments, defined as Strong-Sense Benchmarks (SSB's), which will help establish the FHR validation domain for simulant fluid suitability. These SSB's are more specifically designed to investigate single-phase natural circulation which is the dominant mode of FHR decay heat removal during off-normal conditions. SSB s should be viewed as engineering reference standards and differ from traditional confirmatory experiments in the sense that they are more focused on fundamental physics as opposed to reproducing high levels of physical similarity with the prototypical design. (authors)

  18. Ammonium boranes for the selective complexation of cyanide or fluoride ions in water.

    Science.gov (United States)

    Hudnall, Todd W; Gabbaï, François P

    2007-10-03

    With the recognition of aqueous fluoride and cyanide ions as an objective, we have investigated the anion binding properties of two isomeric ammonium boranes, namely [p-(Mes2B)C6H4(NMe3)]+ ([1]+) and [o-(Mes2B)C6H4(NMe3)]+ ([2]+). These cationic boranes, which could be obtained by reaction of the known 4- and 2-dimesitylboryl-N,N-dimethylaniline with MeOTf, have been investigated both experimentally and computationally. They both react with fluoride and cyanide ions in organic solvents to afford the corresponding fluoroborate/ or cyanoborate/ammonium zwitterions 1F, 1CN, 2F, and 2CN. In aqueous solution, however, these cationic boranes behave as remarkably selective receptors. Indeed, [1]+ only complexes cyanide ions while [2]+ only complexes fluoride ions. In H2O/DMSO 60:40 vol (HEPES 6 mM, pH 7), the cyanide binding constant of [1]+ and the fluoride binding constant of [2]+ are respectively equal to 3.9 (+/-0.1) x 108 and 910 (+/-50) M-1. Structural and computational studies indicate that both steric and electronic effects contribute to the unusual selectivity displayed by these cationic boranes. Owing to favorable Coulombic effects, the para-derivative [1]+ has a very high affinity for cyanide; yet these effects are not sufficiently intense to allow complexation of the more efficiently hydrated and less basic fluoride anion. In the case of the ortho-derivative [2]+, the proximity of the ammonium moiety leads to an increase in the Lewis acidity of the boron center thus making fluoride binding possible. However, steric effects prevent cyanide coordination to the boron center of [2]+. Finally, cation [1]+ and [2]+ bind their dedicated anions reversibly and show a negligible response in the presence of other common anions including Cl-, Br-, I-, NO3-, OAc-, H2PO4-, and HSO4-.

  19. Assessment of the Use of Nitrogen Trifluoride for Purifying Coolant and Heat Transfer Salts in the Fluoride Salt-Cooled High-Temperature Reactor

    International Nuclear Information System (INIS)

    Scheele, Randall D.; Casella, Andrew M.

    2010-01-01

    This report provides an assessment of the use of nitrogen trifluoride for removing oxide and water-caused contaminants in the fluoride salts that will be used as coolants in a molten salt cooled reactor. The Pacific Northwest National Laboratory, in support of the Oak Ridge National Laboratory's program to investigate an advanced molten salt cooled reactor concept for the U.S. Department of Energy, evaluated potential nitrogen trifluoride (NF 3 ) use as an agent for removing oxide and hydroxide contaminants from candidate coolants. These contaminants must be eliminated because they increase the corrosivity of the molten salt to the detriment of the materials of containment that are currently being considered. The baseline purification agent for fluoride coolant salts is hydrogen fluoride (HF) combined with hydrogen (H 2 ). Using HF/H 2 as the reference treatment, we compare HF and NF 3 industrial use, chemical and physical properties, industrial production levels, chemical, toxicity, and reactivity hazards, environmental impacts, effluent management strategies, and reaction thermodynamic values. Because NF 3 is only mildly toxic, non-corrosive, and non-reactive at room temperature, it will be easy to manage the chemical and reactivity hazards during transportation, storage, and normal operations. Industrial experience with NF 3 is also extensive because NF 3 is commonly used as an etchant and chamber cleaner in the electronics industry. In contrast HF is a highly toxic and corrosive gas at room temperature but because of its significance as the most important fluorine-containing chemical there is significant industrial experience managing HF hazards. NF 3 has been identified as having the potential to be a significant contributor to global warming and thus its release must be evaluated and/or managed depending on the amounts that would be released. Because of its importance to the electronics industry, commercial technologies using incineration or plasmas have been

  20. Synthesis of the Complex Fluoride LiBaF3 through a Solvothermal Process

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The complex fluoride LiBaF3 is solvothermally synthesized at 180℃ and characterized by means of X-ray powder diffraction, scanning electron microscopy, thermogravimetric analysis and infrared spectroscopy. In the solvothermal process, the solvents, mole ratios of initial mixtures and reaction temperature play important roles in the growth of the single crystal.

  1. Pre-Conceptual Design of a Fluoride-Salt-Cooled Small Modular Advanced High Temperature Reactor (SmAHTR)

    Energy Technology Data Exchange (ETDEWEB)

    Greene, Sherrell R [ORNL; Gehin, Jess C [ORNL; Holcomb, David Eugene [ORNL; Carbajo, Juan J [ORNL; Ilas, Dan [ORNL; Cisneros, Anselmo T [ORNL; Varma, Venugopal Koikal [ORNL; Corwin, William R [ORNL; Wilson, Dane F [ORNL; Yoder Jr, Graydon L [ORNL; Qualls, A L [ORNL; Peretz, Fred J [ORNL; Flanagan, George F [ORNL; Clayton, Dwight A [ORNL; Bradley, Eric Craig [ORNL; Bell, Gary L [ORNL; Hunn, John D [ORNL; Pappano, Peter J [ORNL; Cetiner, Sacit M [ORNL

    2011-02-01

    This document presents the results of a study conducted at Oak Ridge National Laboratory during 2010 to explore the feasibility of small modular fluoride salt-cooled high temperature reactors (FHRs). A preliminary reactor system concept, SmATHR (for Small modular Advanced High Temperature Reactor) is described, along with an integrated high-temperature thermal energy storage or salt vault system. The SmAHTR is a 125 MWt, integral primary, liquid salt cooled, coated particle-graphite fueled, low-pressure system operating at 700 C. The system employs passive decay heat removal and two-out-of-three , 50% capacity, subsystem redundancy for critical functions. The reactor vessel is sufficiently small to be transportable on standard commercial tractor-trailer transport vehicles. Initial transient analyses indicated the transition from normal reactor operations to passive decay heat removal is accomplished in a manner that preserves robust safety margins at all times during the transient. Numerous trade studies and trade-space considerations are discussed, along with the resultant initial system concept. The current concept is not optimized. Work remains to more completely define the overall system with particular emphasis on refining the final fuel/core configuration, salt vault configuration, and integrated system dynamics and safety behavior.

  2. Method for converting UF5 to UF4 in a molten fluoride salt

    International Nuclear Information System (INIS)

    Bennett, M.R.; Bamberge, C.E.; Kelmers, A.D.

    1980-01-01

    The subject relates to fuel preparation for molten salt breeder reactors, and more particularly to the reconstitution of spent molten fuel salt after fission product removal. During the course of reactor operation, fission products including rare earths and bred-in protactinium build up in the fuel salt and adversely affect the nuclear properties of the fuel. In order to more efficiently operate the reactor, the level of neutron poison fission products must be kept at a minimum. This is accomplished by continuously removing spent fuel from the primary circuit, processing it to remove fission products, and returning the reprocessed molten salt to the primary circuit. It is desirable for safety and economy that the fuel processing plant be a component of the reactor itself and that the salt be kept in the molten state throughout the processing system. (auth)

  3. Geochemical characterization of fluoride in water, table salt, active sediment, rock and soil samples, and its possible relationship with the prevalence of enamel fluorosis in children in four municipalities of the department of Huila (Colombia).

    Science.gov (United States)

    Martignon, Stefania; Opazo-Gutiérrez, Mario Omar; Velásquez-Riaño, Möritz; Orjuela-Osorio, Iván Rodrigo; Avila, Viviana; Martinez-Mier, Esperanza Angeles; González-Carrera, María Clara; Ruiz-Carrizosa, Jaime Alberto; Silva-Hermida, Blanca Cecilia

    2017-06-01

    Fluoride is an element that affects teeth and bone formation in animals and humans. Though the use of systemic fluoride is an evidence-based caries preventive measure, excessive ingestion can impair tooth development, mainly the mineralization of tooth enamel, leading to a condition known as enamel fluorosis. In this study, we investigated the geochemical characterization of fluoride in water, table salt, active sediment, rock and soil samples in four endemic enamel fluorosis sentinel municipalities of the department of Huila, Colombia (Pitalito, Altamira, El Agrado and Rivera), and its possible relationship with the prevalence of enamel fluorosis in children. The concentration of fluoride in drinking water, table salt, active sediment, rock, and soil was evaluated by means of an ion selective electrode and the geochemical analyses were performed using X-ray fluorescence. Geochemical analysis revealed fluoride concentrations under 15 mg/kg in active sediment, rock and soil samples, not indicative of a significant delivery to the watersheds studied. The concentration of fluoride in table salt was found to be under the inferior limit (less than 180 μg/g) established by the Colombian regulations. Likewise, exposure doses for fluoride water intake did not exceed the recommended total dose for all ages from 6 months. Although the evidence does not point out at rocks, soils, fluoride-bearing minerals, fluoridated salt and water, the hypothesis of these elements as responsible of the current prevalence of enamel fluorosis cannot be discarded since, aqueducts might have undergone significant changes overtime.

  4. Defect complexes and thermoluminescence in lithium fluoride. [X radiation

    Energy Technology Data Exchange (ETDEWEB)

    McKeever, S.W.S. (Oklahoma State Univ., Stillwater (USA). Dept. of Physics)

    1984-01-01

    X-ray induced luminescence measurements indicate that the emission wavelength is dependent upon the aggregation state of Mg within the LiF lattice. This suggests a close association between Mg and Ti within a defect complex. Pulse annealing measurements indicate that peak 5 may be due to the dissociation of trimers, followed by charge release.

  5. Effect of fluoridated casein phospopeptide-amorphous-calcium phosphate complex, chlorhexidine fluoride mouthwash on shear bond strength of orthodontic brackets: A comparative in vitro study

    Directory of Open Access Journals (Sweden)

    C A Abdul Shahariyar

    2016-01-01

    Full Text Available Objective: The aim of the current study was to determine the effects of casein phosphopeptide amorphous calcium-phosphate (CPP-ACP complex, chlorhexidine fluoride mouthwash on shear bond strengths (SBSs of orthodontic brackets. Materials and Methods: About sixty extracted healthy human premolar teeth with intact buccal enamel were divided into two equal groups to which brackets were bonded using self-etching primers (SEPs and conventional means respectively. These were further equally divided into three subgroups - (1 control (2 CPP-ACP (3 chlorhexidine fluoride mouthwash. The SBSs were then measured using a universal testing machine. Results: SBS of the conventional group was significantly higher than the self-etching group. The intragroup differences were statistically insignificant. Conclusion: CPP-ACP, chlorhexidine fluoride mouthwash did not adversely affect SBS of orthodontic brackets irrespective of the method of conditioning. Brackets bonded with conventional technique showed greater bond strengths as compared to those bonded with SEP.

  6. Fluoride salts as phase change materials for thermal energy storage in the temperature range 1000-1400 K

    Science.gov (United States)

    Misra, Ajay K.

    1988-01-01

    Eutectic compositions and congruently melting intermediate compounds in binary and ternary fluoride salt systems were characterized for potential use as latent heat of fusion phase change materials to store thermal energy in the temperature range 1000-1400 K. The melting points and eutectic compositions for many systems with published phase diagrams were experimentally verified and new eutectic compositions having melting points between 1000 and 1400 K were identified. Heats of fusion of several binary and ternary eutectics and congruently melting compounds were experimentally measured by differential scanning calorimetry. For a few systems in which heats of mixing in the melts have been measured, heats of fusion of the eutectics were calculated from thermodynamic considerations and good agreement was obtained between the measured and calculated values. Several combinations of salts with high heats of fusion per unit mass (greater than 0.7 kJ/g) have been identified for possible use as phase change materials in advanced solar dynamic space power applications.

  7. Speciation of Zinc Mixed Ligand Complexes in Salt Water Systems ...

    African Journals Online (AJOL)

    Speciation of Zinc Mixed Ligand Complexes in Salt Water Systems. ... method has been used to study heavy metal interaction in model lake water in KNO3 ... is of no consequential effect because in its normal state, the [OH-] of the lake water is ...

  8. Effect of using FLiBe and FLiNaBe molten salts bearing plutonium fluorides on the neutronic performance of PACER

    International Nuclear Information System (INIS)

    Acir, Adem

    2012-01-01

    In this paper, the effects of using FLiBe and FLiNaBe Molten Salts Bearing Plutonium Fluorides on the neutronic performance of the PACER are investigated. The optimum radial thickness for tritium self-sufficiency of the blankets addition of plutonium fluorides to FLiNaBe (LiF-/NaF BeF 2 ) and FLiBe (LiF-/BeF 2 ) of a dual purpose modified PACER concept are determined. The calculations are carried out with the one dimensional transport code XSDRNPM/SCALE5. The tritium breeding capacities of FLiNaBe and FLiBe with addition of plutonium fluorides in molten salt zone are investigated and compared. The optimum molten salt zone thickness is computed as 155 cm for tritium self-sufficiency of the blankets using FLiBe +1% PuF 4 whereas, the optimum thickness with FLiNaBe +1% PuF 4 is calculated as 170 cm. In addition, neutron transport calculations have been performed to evaluate the energy multiplication factor, total fission rate, displacement per atom and helium gas generation for optimal radial thickness in the blanket. Also, the tritium production and the radiation damage limits should be evaluated together in a fusion blanket for determining the optimum thickness of molten salt layer. (orig.)

  9. Sustainability of thorium-uranium in pebble-bed fluoride salt-cooled High Temperature Reactor - 15171

    International Nuclear Information System (INIS)

    Zhu, G.; Zou, Y.; Xu, Hongjie

    2015-01-01

    Sustainability of thorium fuel in a pebble-bed fluoride salt-cooled high temperature reactor (PB-FHR) is investigated to find the feasible region of high discharge burnup and negative FLiBe (2LiF-BeF 2 ) salt temperature reactivity coefficient (TRC). Dispersion fuel or pellet fuel with SiC cladding and SiC matrix is used to replace the tri-structural-isotropic (TRISO) coated particle system for increasing heavy metal loading and decreasing excessive moderation. In order to analyze the neutronic characteristics, an equilibrium calculation method of thorium fuel self-sustainability is developed. We have compared 2 refueling schemes (mixing flow pattern and directional flow pattern) and 2 kinds of reflector materials (SiC and graphite). This method has found that the feasible regions of breeding and negative FLiBe TRC is between 20 vol% and 62 vol% heavy metal loading in the fuel. A discharge burnup could be achieved up to about 200 MWd/kgHM. The case with directional flow pattern and SiC reflector showed superior burnup characteristics but the worst radial power peak factor, while the case with mixing flow pattern and SiC reflector, which was the best tradeoff between discharge burnup and radial power peak factor, could provide burnup of 140 MWd/kgHM and about 1.4 radial power peak factor with 50 vol% dispersion fuel. In addition, FLiBe salt displays good neutron properties as a coolant of quasi-fast reactors due to the strong 9 Be(n,2n) reaction and low neutron absorption of 6 Li (even at 1000 ppm) in fast spectrum. Preliminary thermal hydraulic calculation shows good safety margins. The greatest challenge of this reactor may be the very long irradiation time of the pebble fuel. (authors)

  10. Status of tellurium--hastelloy N studies in molten fluoride salts

    International Nuclear Information System (INIS)

    Keiser, J.R.

    1977-10-01

    Tellurium, which is a fission product in nuclear reactor fuels, can embrittle the surface grain boundaries of nickel-base structural materials. This report summarizes results of an experimental investigation conducted to understand the mechanism and to develop a means of controlling this embrittlement in the alloy Hastelloy N. The addition of a chromium telluride to salt can be used to provide small partial pressures of tellurium simulating a reactor environment where tellurium appears as a fission product. The intergranular embrittlement produced in Hastelloy N when exposed to this chromium telluride-salt mixture can be reduced by adding niobium to the Hastelloy N or by controlling the oxidation potential of the salt in the reducing range

  11. Structure of tungsten electrodeposited from oxide chloride-fluoride molten salts

    International Nuclear Information System (INIS)

    Pavlovskij, V.A.; Reznichenko, V.A.

    1998-01-01

    Investigation results on the influence of electrolysis parameters and electrolyte composition on tungsten cathode deposit structure are presented. The electrolysis was performed in NaCl-NaF-WO 3 molten salts using tungsten and tungsten coated molybdenum cathodes. Morphological and metallographic studies of tungsten crystals were carrier out. Tungsten deposits were obtained in the form of crystalline conglomerates, sponge and high dispersity powder

  12. Fluoride exposure of East African consumers using alkaline salt deposits known as magadi (trona) as a food preparation aid

    DEFF Research Database (Denmark)

    Nielsen, Joan Maj; Dahi, E.

    2002-01-01

    that the fluoride content varied significantly even for magadi originating from the individual lake, e. g. the fluoride content in magadi from Lake Magadi was between 0.1 and 8.7 mg g(-1). In a lump of magadi originating from Lake Magadi, it was found that the fluoride content in 20 smaller part samples was subject...

  13. An integrated model of tritium transport and corrosion in Fluoride Salt-Cooled High-Temperature Reactors (FHRs) – Part I: Theory and benchmarking

    Energy Technology Data Exchange (ETDEWEB)

    Stempien, John D., E-mail: john.stempien@inl.gov; Ballinger, Ronald G., E-mail: hvymet@mit.edu; Forsberg, Charles W., E-mail: cforsber@mit.edu

    2016-12-15

    Highlights: • A model was developed for use with FHRs and benchmarked with experimental data. • Model results match results of tritium diffusion experiments. • Corrosion simulations show reasonable agreement with molten salt loop experiments. • This is the only existing model of tritium transport and corrosion in FHRs. • Model enables proposing and evaluating tritium control options in FHRs. - Abstract: The Fluoride Salt-Cooled High-Temperature Reactor (FHR) is a pebble bed nuclear reactor concept cooled by a liquid fluoride salt known as “flibe” ({sup 7}LiF-BeF{sub 2}). A model of TRITium Diffusion EvolutioN and Transport (TRIDENT) was developed for use with FHRs and benchmarked with experimental data. TRIDENT is the first model to integrate the effects of tritium production in the salt via neutron transmutation, with the effects of the chemical redox potential, tritium mass transfer, tritium diffusion through pipe walls, tritium uptake by graphite, selective chromium attack by tritium fluoride, and corrosion product mass transfer. While data from a forced-convection polythermal loop of molten salt containing tritium did not exist for comparison, TRIDENT calculations were compared to data from static salt diffusion tests in flibe and flinak (0.465LiF-0.115NaF-0.42KF) salts. In each case, TRIDENT matched the transient and steady-state behavior of these tritium diffusion experiments. The corrosion model in TRIDENT was compared against the natural convection flow-loop experiments at the Oak Ridge National Laboratory (ORNL) from the 1960s and early 1970s which used Molten Salt Reactor Experiment (MSRE) fuel-salt containing UF{sub 4}. Despite the lack of data required by TRIDENT for modeling the loops, some reasonable results were obtained. The TRIDENT corrosion rates follow the experimentally observed dependence on the square root of the product of the chromium solid-state diffusion coefficient with time. Additionally the TRIDENT model predicts mass

  14. Role and status of scaled experiments in the development of fluoride-salt-cooled, high-temperature reactors - 15185

    International Nuclear Information System (INIS)

    Zweibaum, N.; Huddar, L.; Laufer, M.R.; Peterson, P.F.; Hughes, J.T.; Blandford, E.D.; Scarlat, R.O.

    2015-01-01

    Development of fluoride-salt-cooled, high-temperature reactor (FHR) technology requires a better understanding of key hydrodynamic and heat transfer phenomena associated with this novel class of reactors. The use of simulant fluids that can match the most important non dimensional numbers between scaled experiments and prototypical FHR systems enables integral effects tests (IETs) to be performed at reduced cost and difficulty for FHR code validation. The University of California at Berkeley (UCB) and the University of New Mexico (UNM) have built a number of IETs and separate effects tests to investigate pebble-bed FHR (PB-FHR) phenomenology using water or simulant oils such as Dowtherm A. PB-FHR pebble motion and porous media flow dynamics have been investigated with UCB's pebble recirculation experiments using water and plastic spheres. Transient flow of high-Prandtl-number fluids around hot spheres has also been investigated by UCB to measure Nusselt numbers in pebble-bed cores, using simulant oils and copper spheres. Finally, single-phase forced/natural circulation has been investigated using the scaled height, reduced flow area loops of the Compact Integral Effects Test facility at UCB and a multi-flow regime loop at UNM, using Dowtherm A oil. The scaling methodology and status of these ongoing experiments are described here

  15. Synthesis of Backfunctionalized Imidazolinium Salts and NHC Carbene Complexes

    Science.gov (United States)

    2017-04-02

    Backfunctionalized Imidazolinium salts and NHC carbene complexes – Initial Research – Unintended Discovery – Survey chemistry of aromatic systems – Expansion of...survey chemistry to aliphatics • Conclusions and Future Directions Introduction 3 Distribution A: Approved for Public Release; Distribution Unlimited...AFRL – Tenant of Edwards AFB since late ‘50s – Full scale testing of the Atlas rockets (Gemini missions) – Initial testing of the F-1 engine (Apollo

  16. Ionic liquid and solid HF equivalent amine-poly(hydrogen fluoride) complexes effecting efficient environmentally friendly isobutane-isobutylene alkylation.

    Science.gov (United States)

    Olah, George A; Mathew, Thomas; Goeppert, Alain; Török, Béla; Bucsi, Imre; Li, Xing-Ya; Wang, Qi; Marinez, Eric R; Batamack, Patrice; Aniszfeld, Robert; Prakash, G K Surya

    2005-04-27

    Isoparaffin-olefin alkylation was investigated using liquid as well as solid onium poly(hydrogen fluoride) catalysts. These new immobilized anhydrous HF catalysts contain varied amines and nitrogen-containing polymers as complexing agents. The liquid poly(hydrogen fluoride) complexes of amines are typical ionic liquids, which are convenient media and serve as HF equivalent catalysts with decreased volatility for isoparaffin-olefin alkylation. Polymeric solid amine:poly(hydrogen fluoride) complexes are excellent solid HF equivalents for similar alkylation acid catalysis. Isobutane-isobutylene or 2-butene alkylation gave excellent yields of high octane alkylates (up to RON = 94). Apart from their excellent catalytic performance, the new catalyst systems significantly reduce environmental hazards due to the low volatility of complexed HF. They represent a new, "green" class of catalyst systems for alkylation reactions, maintaining activity of HF while minimizing its environmental hazards.

  17. Fluoride-Salt-Cooled High-Temperature Reactor (FHR) for Power and Process Heat

    Energy Technology Data Exchange (ETDEWEB)

    Forsberg, Charles [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Hu, Lin-wen [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Peterson, Per [Univ. of California, Berkeley, CA (United States); Sridharan, Kumar [Univ. of Wisconsin, Madison, WI (United States)

    2015-01-21

    In 2011 the U.S. Department of Energy through its Nuclear Energy University Program (NEUP) awarded a 3- year integrated research project (IRP) to the Massachusetts Institute of Technology (MIT) and its partners at the University of California at Berkeley (UCB) and the University of Wisconsin at Madison (UW). The IRP included Westinghouse Electric Company and an advisory panel chaired by Regis Matzie that provided advice as the project progressed. The first sentence of the proposal stated the goals: The objective of this Integrated Research Project (IRP) is to develop a path forward to a commercially viable salt-cooled solid-fuel high-temperature reactor with superior economic, safety, waste, nonproliferation, and physical security characteristics compared to light-water reactors. This report summarizes major results of this research.

  18. Fluoride-Salt-Cooled High-Temperature Reactor (FHR) for Power and Process Heat

    International Nuclear Information System (INIS)

    Forsberg, Charles; Hu, Lin-wen; Peterson, Per; Sridharan, Kumar

    2015-01-01

    In 2011 the U.S. Department of Energy through its Nuclear Energy University Program (NEUP) awarded a 3- year integrated research project (IRP) to the Massachusetts Institute of Technology (MIT) and its partners at the University of California at Berkeley (UCB) and the University of Wisconsin at Madison (UW). The IRP included Westinghouse Electric Company and an advisory panel chaired by Regis Matzie that provided advice as the project progressed. The first sentence of the proposal stated the goals: The objective of this Integrated Research Project (IRP) is to develop a path forward to a commercially viable salt-cooled solid-fuel high-temperature reactor with superior economic, safety, waste, nonproliferation, and physical security characteristics compared to light-water reactors. This report summarizes major results of this research.

  19. Combined subchronic fluoride-lead intoxication and its attenuation with the help of a complex of bioprotectors.

    Science.gov (United States)

    Katsnelson, B A; Privalova, L I; Kireyeva, Y P; Yeremenko, O S; Sutunkova, M P; Valamina, I E; Varaksin, A N; Panov, V G; Kazmer, J I

    2012-01-01

    Combined toxicity of lead and fluoride has been studied insufficiently, and there is no known information about attempts to inhibit it with any bioprotectors. Lead acetate and sodium fluoride, administered separately or in combination, were injected i.p. to rats at isoeffective sublethal doses 3 times a week for 6 weeks. Some of the rats were exposed to the same combination against the background of oral administration of a bioprotector complex (BPC) comprising pectin, glutamate, and multivitamin/multimineral preparations. Following exposure, functional and biochemical indices and histopathological examinations of the femur of exposed and control rats were evaluated for signs of toxicity. We have shown that with regard to a number of effects on the organism level the combined toxicity of lead and fluoride may be evaluated as additive or even superadditive, but lead reduces fluoride accumulation in the bone, and pathological changes in the bone tissue proved to be less marked for combined exposure compared with separate exposures. The BPC has been demonstrated to attenuate a range of the combined harmful effects of lead and fluoride, including those on the bone tissue. In spite of the fact that fluoride and lead may reciprocally attenuate their harmful effects on the bone tissue in case of combined exposure, they prove to be more toxic for soft tissues just in combination than when administered separately. The development of combined intoxication may be substantially inhibited by means of the tested set of innocuous biologically active agents.

  20. Method for identifying particulate fluoride compounds

    Energy Technology Data Exchange (ETDEWEB)

    Tufts, B J

    1960-01-01

    A method is described for identifying particulates containing fluorides and other complex fluorine compounds such as fluorosilicate in samples collected on membrane filters. The filter is treated with lead chloride to precipitate lead chlorofluoride at each fluoride-containing spot. This microspot is identified by examination in a light microscope. Sulfate and phosphate, which also precipitate if present, can be distinguished and do not interfere. Calibrations are given for the fluorides and the more insoluble salts, relating the original particle size to the reaction site size. Thus, the mass of the particles can be calculated. Results of some field tests in an area of fluoride pollution are given, and compared with standard testing procedures.

  1. Electrospun poly(vinylidene fluoride) copolymer/octahydroxy-polyhedral oligomeric silsesquioxane nanofibrous mats as ionic liquid host: enhanced salt dissociation and its function in electrochromic device

    International Nuclear Information System (INIS)

    Zhou, Rui; Pramoda, Kumari Pallathadka; Liu, Wanshuang; Zhou, Dan; Ding, Guoqiang; He, Chaobin; Leong, Yew Wei; Lu, Xuehong

    2014-01-01

    Highlights: • The well dispersed POSS-OH promotes the dissociation of both LiClO 4 and BMIM + BF 4 − . • POSS-OH significantly increases the ionic conductivity and lithium transference number. • POSS-OH containing electrolyte improves the optical contrast of electrochromic device. - Abstract: Electrospun polymer nanofibrous mats loaded with ionic liquids (ILs) and lithium salts are promising non-volatile electrolytes owing to their high ionic conductivities. However, the large cations of ILs are difficult to diffuse into solid electrodes, whereas the lithium ions in ILs tend to form anionic complexes with the IL anions, reducing the number of free lithium ions. To address these issues, octa(3-hydroxy-3-methylbutyldimethylsiloxy) polyhedral oligomeric silsesquioxane (POSS-OH), which has large specific surface area and functionality number, is incorporated into electrospun poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-co-HFP) nanofibrous mats, and the mats are used to host LiClO 4 /1-butyl-3-methylimidazolium tetrafluoroborate (BMIM + BF 4 − ). It is found that POSS-OH can significantly increase both ionic conductivity and lithium transference number of the electrolytes owing to the Lewis acid-base interactions of POSS-OH with ClO 4 − and BF 4 − . The electrochromic device using the hybrid mat (with 5 wt% POSS-OH) loaded with LiClO 4 /BMIM + BF 4 − as the electrolyte shows significantly improved transmittance contrast and switching time, as a result of increased number of free lithium ions

  2. Method of purifying uranium tetrafluoride hydrate and preparing uranium (VI) peroxide hydrate using a fluoride complexing agent

    International Nuclear Information System (INIS)

    Barreiro, A.J.; Lowe, C.M.T.; Lefever, J.A.; Pyman, R.L.

    1983-01-01

    The annual production of phosphate rock, on the order of about 30-40 million tons yearly, represents several million pounds of uranium. The present invention provides a process of purifying uranium tetrafluoride hydrate to produce a uranium (VI) peroxide product meeting 'yellow cake' standards using a double precipitation procedure. A fluoride complexing agent is used in the precipitation

  3. Highly selective single-use fluoride ion optical sensor based on aluminum(III)-salen complex in thin polymeric film

    International Nuclear Information System (INIS)

    Badr, Ibrahim H.A.; Meyerhoff, Mark E.

    2005-01-01

    A highly selective optical sensor for fluoride ion based on the use of an aluminum(III)-salen complex as an ionophore within a thin polymeric film is described. The sensor is prepared by embedding the aluminum(III)-salen ionophore and a suitable lipophilic pH-sensitive indicator (ETH-7075) in a plasticized poly(vinyl chloride) (PVC) film. Optical response to fluoride occurs due to fluoride extraction into the polymer via formation of a strong complex with the aluminum(III)-salen species. Co-extraction of protons occurs simultaneously, with protonation of the indicator dye yielding the optical response at 529 nm. Films prepared using dioctylsebacate (DOS) are shown to exhibit better response (e.g., linear range, detection limit, and optical signal stability) compared to those prepared using ortho-nitrophenyloctyl ether (o-NPOE). Films formulated with aluminum(III)-salen and ETH-7075 indicator in 2 DOS:1 PVC, exhibit a significantly enhanced selectivity for fluoride over a wide range of lipophilic anions including salicylate, perchlorate, nitrate, and thiocyanate. The optimized films exhibit a sub-micromolar detection limit, using glycine-phosphate buffer, pH 3.00, as the test sample. The response times of the fluoride optical sensing films are in the range of 1-10 min depending on the fluoride ion concentration in the sample. The sensor exhibits very poor reversibility owing to a high co-extraction constant (log K = 8.5 ± 0.4), indicating that it can best be employed as a single-use transduction device. The utility of the aluminum(III)-salen based fluoride sensitive films as single-use sensors is demonstrated by casting polymeric films on the bottom of standard polypropylene microtiter plate wells (96 wells/plate). The modified microtiter plate optode format sensors exhibit response characteristics comparable to the classical optode films cast on quartz slides. The modified microtiter is utilized for the analysis of fluoride in diluted anti-cavity fluoride rinse

  4. Graft polymerization of acrylic acid and methacrylic acid onto poly(vinylidene fluoride) powder in presence of metallic salt and sulfuric acid

    Science.gov (United States)

    Deng, Bo; Yu, Yang; Zhang, Bowu; Yang, Xuanxuan; Li, Linfan; Yu, Ming; Li, Jingye

    2011-02-01

    Poly(vinylidene fluoride) (PVDF) powder was grafted with acrylic acid (AAc) or methacrylic acid (MAA) by the pre-irradiation induced graft polymerization technique. The presence of graft chains was proven by FT-IR spectroscopy. The degree of grafting (DG) was calculated by the acid-base back titration method. The synergistic effect of acid and Mohr's salt on the grafting kinetics was examined. The results indicated that adding sulfuric acid and Mohr's salt simultaneously in AAc or MAA solutions led to a strong enhancement in the degree of grafting. The grafted PVDF powder was cast into microfiltration (MF) membranes using the phase inversion method and some properties of the obtained MF membranes were characterized.

  5. Graft polymerization of acrylic acid and methacrylic acid onto poly(vinylidene fluoride) powder in presence of metallic salt and sulfuric acid

    Energy Technology Data Exchange (ETDEWEB)

    Deng Bo [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, No. 2019, Jialuo Road, Jiading Dist., 201800 Shanghai (China); Yu Yang; Zhang Bowu; Yang Xuanxuan [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, No. 2019, Jialuo Road, Jiading Dist., 201800 Shanghai (China); Graduate University of Chinese Academy of Sciences, No. 19, Yuquan Road, Shijingshan Dist., 100049 Beijing (China); Li Linfan; Yu Ming [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, No. 2019, Jialuo Road, Jiading Dist., 201800 Shanghai (China); Li Jingye, E-mail: jingyeli@sinap.ac.c [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, No. 2019, Jialuo Road, Jiading Dist., 201800 Shanghai (China)

    2011-02-15

    Poly(vinylidene fluoride) (PVDF) powder was grafted with acrylic acid (AAc) or methacrylic acid (MAA) by the pre-irradiation induced graft polymerization technique. The presence of graft chains was proven by FT-IR spectroscopy. The degree of grafting (DG) was calculated by the acid-base back titration method. The synergistic effect of acid and Mohr's salt on the grafting kinetics was examined. The results indicated that adding sulfuric acid and Mohr's salt simultaneously in AAc or MAA solutions led to a strong enhancement in the degree of grafting. The grafted PVDF powder was cast into microfiltration (MF) membranes using the phase inversion method and some properties of the obtained MF membranes were characterized.

  6. Graft polymerization of acrylic acid and methacrylic acid onto poly(vinylidene fluoride) powder in presence of metallic salt and sulfuric acid

    International Nuclear Information System (INIS)

    Deng Bo; Yu Yang; Zhang Bowu; Yang Xuanxuan; Li Linfan; Yu Ming; Li Jingye

    2011-01-01

    Poly(vinylidene fluoride) (PVDF) powder was grafted with acrylic acid (AAc) or methacrylic acid (MAA) by the pre-irradiation induced graft polymerization technique. The presence of graft chains was proven by FT-IR spectroscopy. The degree of grafting (DG) was calculated by the acid-base back titration method. The synergistic effect of acid and Mohr's salt on the grafting kinetics was examined. The results indicated that adding sulfuric acid and Mohr's salt simultaneously in AAc or MAA solutions led to a strong enhancement in the degree of grafting. The grafted PVDF powder was cast into microfiltration (MF) membranes using the phase inversion method and some properties of the obtained MF membranes were characterized.

  7. Surface Complexation Modeling of Fluoride Adsorption by Soil and the Role of Dissolved Aluminum on Adsorption

    Science.gov (United States)

    Padhi, S.; Tokunaga, T.

    2017-12-01

    Adsorption of fluoride (F) on soil can control the mobility of F and subsequent contamination of groundwater. Hence, accurate evaluation of adsorption equilibrium is a prerequisite for understanding transport and fate of F in the subsurface. While there have been studies for the adsorption behavior of F with respect to single mineral constituents based on surface complexation models (SCM), F adsorption to natural soil in the presence of complexing agents needs much investigation. We evaluated the adsorption processes of F on a natural granitic soil from Tsukuba, Japan, as a function of initial F concentration, ionic strength, and initial pH. A SCM was developed to model F adsorption behavior. Four possible surface complexation reactions were postulated with and without including dissolved aluminum (Al) and Al-F complex sorption. Decrease in F adsorption with the increase in initial pH was observed in between the initial pH range of 4 to 9, and a decrease in the rate of the reduction of adsorbed F with respect to the increase in the initial pH was observed in the initial pH range of 5 to 7. Ionic strength variation in the range of 0 to 100mM had insignificant effect on F removal. Changes in solution pH were observed by comparing the solution before and after F adsorption experiments. At acidic pH, the solution pH increased, whereas at alkaline pH, the solution pH decreased after equilibrium. The SCM including dissolved Al and the adsorption of Al-F complex can simulate the experimental results quite successfully. Also, including dissolved Al and the adsorption of Al-F complex to the model explained the change in solution pH after F adsorption.

  8. Determination of the Magnetic Structure of Complex anti-Perovskite Fluorides by Neutron Diffraction

    Science.gov (United States)

    Felder, Justin; Yeon, Jeongho; Zur Loye, Hans-Conrad

    An unusual family of anti-perovskite fluorides consisting of complex ions as the A, B, and X building units has been synthesized as single crystals. This family of anti-perovskites provides a unique framework to probe the magnetic properties of transition metals. Presented here is the Fe endmember of the family: [Cu(H2O)4]3[FeF6]2. The iron member exhibits complex magnetic behavior at low temperatures, which has been probed by magnetometry and neutron diffraction experiments. Presented here are the results from the anisotropic magnetometry study as well as the magnetic spin structure as determined by neutron diffraction experiments. The materials presented here represent an interesting class of perovskites that are as-yet unexplored. Given the wide range of properties possible in perovskites and related structures, it is reasonable to expect that further exploration of these materials will reveal many interesting attributes; both chemical and physical. United States Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, Award DE-SC0008664.

  9. Thermal diffusivity measurement of molten fluoride salt containing ThF4 (improvement of the simple ceramic cell)

    International Nuclear Information System (INIS)

    Kato, Y.; Araki, N.; Kobayashi, K.; Makino, A.

    1985-01-01

    Design conditions of a cylindrical ceramic cell are estimated which can be used to measure the absolute value of thermal diffusivity of molten salts by applying the stepwise heating method. Molten salt is expected to be used in nuclear systems such as the Molten-Salt Reactor, the Accelerator Molten-Salt Breeder, the Fusion Reactor Blanket Coolant, the Fuel Reprocessing System, and so on

  10. Fluoridated Water

    Science.gov (United States)

    ... Genetics Services Directory Cancer Prevention Overview Research Fluoridated Water On This Page What is fluoride, and where is it found? What is water fluoridation? When did water fluoridation begin in the ...

  11. Influence of complexing on physicochemical properties of polymer-salt solutions

    International Nuclear Information System (INIS)

    Ostroushko, A.A.; Yushkova, S.M.; Koridze, N.V.; Skobkoreva, N.V.; Zhuravleva, L.I.; Palitskaya, T.A.; Antropova, S.V.; Ostroushko, I.P.; AN SSSR, Moscow

    1993-01-01

    Using the methods of spectrophotometry, viscosimetry, conductometry the influence of salt-polymer complexing processes on physicochemical prperties of aqueous solutions of yttrium, barium, copper nitrates and formates with polyvinyl alcohol was studied. Change of dynamic viscosity, specific electric conductivity of solutions in the process of complexing was shown. Thermal effects of salt-polymer interaction were measured. It is shown that decrease of transition temperature of polymer to plastic state in films, temperature and effective activation energy of salt decomposition is also connected with complexing. Effective values of surface tension on the boundary with air are measured. Coefficients of cation diffusion in polymer-salt solutions are estimated

  12. Dissociation of gaseous complex fluorides MMnF3 and MMnF4 (M= Li - Cs)

    International Nuclear Information System (INIS)

    Sidorov, L.N.; Gubarevich, V.D.

    1982-01-01

    Mass spectrometric determination of dissociation enthalpies of gaseous complex fluorides CsMnF 3 and CsMnF 4 into neutral and charged particles is carried out using techniques of isothermal evaporation, electron impact and study of ion-molecular equilibria. As a result formation enthalpy values of CsMnFsub(3 gas) and CsMnFsub(4 gas) at T=298 are obtained, being -285.4 and -359.9 kcal/mol respectively

  13. Fission products behavior in molten fluoride salts: Speciation of La{sup 3+} and Cs{sup +} in melts containing oxide ions

    Energy Technology Data Exchange (ETDEWEB)

    Rollet, Anne-Laure [CEMHTI, Conditions Extremes et Materiaux: Haute Temperature et Irradiation, CNRS, Universite d' Orleans, 1D avenue de la recherche scientifique, 45071 Orleans cedex 2 (France); PECSA, Physico-chimie des Electrolytes, Colloiedes et Sciences Analytiques, CNRS-UPMC-ESPCI, 4 place Jussieu, 75005 Paris (France); Veron, Emmanuel [CEMHTI, Conditions Extremes et Materiaux: Haute Temperature et Irradiation, CNRS, Universite d' Orleans, 1D avenue de la recherche scientifique, 45071 Orleans cedex 2 (France); Bessada, Catherine, E-mail: catherine.bessada@cnrs-orleans.fr [CEMHTI, Conditions Extremes et Materiaux: Haute Temperature et Irradiation, CNRS, Universite d' Orleans, 1D avenue de la recherche scientifique, 45071 Orleans cedex 2 (France)

    2012-10-15

    Graphical abstract: - Abstract: In this paper we address the effects of fission products on the speciation in molten fluoride salts. Numerous systems with cross-connections have been investigated in order to better identify the influence of CsF in a fluoride melt containing rare earth and oxides : LaF{sub 3}-AF (A = Li, Na, K, Rb and Cs), LaF{sub 3}-LiF-CsF, LaF{sub 3}-LiF-CaF{sub 2}, LaF{sub 3}-LiF-CaO, LaF{sub 3}-LiF-CaO-CsF. In this goal, we performed high temperature NMR experiments and followed in situ the evolution of {sup 19}F, {sup 23}Na, {sup 85}Rb, {sup 133}Cs and {sup 139}La NMR chemical shifts. In LaF{sub 3}-AF-CsF and LaF{sub 3}-AF-CaF{sub 2} systems, the coordination number of lanthanum cation ranges from 6 to 8 depending on the LaF{sub 3} concentration and on the polarizability of the other cations. The addition of oxide (CaO) in the latter mixtures leads to the formation of lanthanum oxyfluoride species that precipitate in LaOF when CaO concentration is increased. The addition of CsF to LaF{sub 3}-LiF-CaO yields to a displacement of the dissolved versus precipitated LaOF proportion.

  14. Application of membrane LaF3 electrode in the determination of stability constants of Uranyl Fluoride complex in solution

    International Nuclear Information System (INIS)

    Muzakky; Iswani GS; Mintolo

    1996-01-01

    A membrane electrode LaF 3 has been applied in the determination of uranyl fluoride complex stability constant in solution. The determination is based on the detection of free F ion in solution as a result of hydrolysis reaction (process) of uranyl ions into the uranyl hydroxide form at low pH. The experiment results showed that there was no effect of ammonium carbonate 2 M titran, flow rate on the electrode response. The F release is optimum at pH 1. The free F ion in solution is calculated from the standard curve at pH 1, after the fluoride concentration at the same pH has been corrected. Using the plot of average number of ligand binding (n) versus minus log of free ligand (-log F) the value of β1 = 4.4, β2 = 7.48, β3=9.73, and β4 = 11.67

  15. A study of salt effects on the complexation between beta-cyclodextrins and bile salts based on the Hofmeister series

    DEFF Research Database (Denmark)

    Holm, Rene; Schonbeck, Christian; Somprasirt, Pitchayanun

    2014-01-01

    bound drug molecules. The influence of Hofmeister ions on the binding constants of complexes between CDs (β-CD and hydroxypropylated β-CD) and bile salts (glycocholate and glycochenodeoxycholate) were examined by isothermal titration calorimetry. The chaotropic anions tended to weaken these inclusion...

  16. Salt fluxes in a complex river mouth system of Portugal.

    Directory of Open Access Journals (Sweden)

    Nuno Vaz

    Full Text Available Measurements of velocity and salinity near the mouth and head of the Espinheiro channel (Ria de Aveiro lagoon, Portugal are used to study the local variation of physical water properties and to assess the balance, under steady conditions, between the seaward salt transport induced by river discharge and the landward dispersion induced by various mixing mechanisms. This assessment is made using data sampled during complete tidal cycles. Under the assumption that the estuarine tidal channel is laterally homogeneous and during moderate tidal periods (except for one survey, currents and salinity data were decomposed into various spatial and temporal means and their deviations. Near the channel's mouth, the main contributions to the salt transport are the terms due to freshwater discharge and the tidal correlation. Near the channel's head, this last term is less important than the density driven circulation, which is enhanced by the increase in freshwater discharge. The remaining terms, which are dependent on the deviations from the mean depth have a smaller role in the results of salt transport. The computed salt transport per unit width of a section perpendicular to the mean flow is in close agreement to the sum of the advective and dispersive terms (within or very close to 12%. An imbalance of the salt budget across the sections is observed for all the surveys. Considerations are made on how this approach can inform the management of hazardous contamination and how to use these results to best time the release of environmental flows during dry months.

  17. Metal fluoride complexes of Na,K-ATPase: characterization of fluoride-stabilized phosphoenzyme analogues and their interaction with cardiotonic steroids.

    Science.gov (United States)

    Cornelius, Flemming; Mahmmoud, Yasser A; Toyoshima, Chikashi

    2011-08-26

    The Na,K-ATPase belongs to the P-type ATPase family of primary active cation pumps. Metal fluorides like magnesium-, beryllium-, and aluminum fluoride act as phosphate analogues and inhibit P-type ATPases by interacting with the phosphorylation site, stabilizing conformations that are analogous to specific phosphoenzyme intermediates. Cardiotonic steroids like ouabain used in the treatment of congestive heart failure and arrhythmias specifically inhibit the Na,K-ATPase, and the detailed structure of the highly conserved binding site has recently been described by the crystal structure of the shark Na,K-ATPase in a state analogous to E2·2K(+)·P(i) with ouabain bound with apparently low affinity (1). In the present work inhibition, and subsequent reactivation by high Na(+), after treatment of shark Na,K-ATPase with various metal fluorides are characterized. Half-maximal inhibition of Na,K-ATPase activity by metal fluorides is in the micromolar range. The binding of cardiotonic steroids to the metal fluoride-stabilized enzyme forms was investigated using the fluorescent ouabain derivative 9-anthroyl ouabain and compared with binding to phosphorylated enzyme. The fastest binding was to the Be-fluoride stabilized enzyme suggesting a preformed ouabain binding cavity, in accord with results for Ca-ATPase where Be-fluoride stabilizes the E2-P ground state with an open luminal ion access pathway, which in Na,K-ATPase could be a passage for ouabain. The Be-fluoride stabilized enzyme conformation closely resembles the E2-P ground state according to proteinase K cleavage. Ouabain, but not its aglycone ouabagenin, prevented reactivation of this metal fluoride form by high Na(+) demonstrating the pivotal role of the sugar moiety in closing the extracellular cation pathway.

  18. Antimicrobial Effects of Sodium Fluoride, Xylitol and Metals Salts on in Vitro Growth Inhibition, Acid Production and Ultrastructure of Streptococcus mutans

    International Nuclear Information System (INIS)

    El-Mongy, T.M.; Abd EI-Aziz, A.B.

    2009-01-01

    This study aimed to evaluate the effects of sodium fluoride (NaF), dietary sugars, sugar alcohols (xylitol and sorbitol) and different metals salts either separately or in combination, by different concentrations at different ph, on the growth inhibition, acid production and ultra structure of Streptococcus mutans. NaF was more effective at low ph, when NaF was added to actively growing Streptococcus mutans broth culture, the growth rate was unaffected by 75 ppm F-, slowed by 150 ppm F-, and immediately arrested by 300 or 600 ppm F-. On the other hand, the best effect of xylitol was at high ph. The effect of xylitol was more marked in the presence of NaF as the acid production was inhibited and the ph did not fall to 5.0. The response of Streptococcus mutans to metals salts was typical of this organism's response to a number of trace metals above optimum concentrations of which may be inhibitory. Synergistic effect observed by addition of metals salts by concentration ranged from 0.2 to 5.0 mML-1, 300 ppm NaF and 5% xylitol. This formula can work at any ph value and causes no drop of the broth culture ph to below 5.0 which is the optimal ph for growth and multiplication of Streptococcus mutans, so this formula worked as ph buffer regulation and growth inhibition for S. mutans. Low concentration of this combined formula after 5 min only at 5.0 and 7.0 ph values caused effective complete destruction of the bacterial viable cells and this effect was observed clearly by Electron Microscope photo graph

  19. Microwave spectrum, dipole moment, and internal dynamics of the methyl fluoride-carbonyl sulfide weakly bound complex.

    Science.gov (United States)

    Serafin, Michal M; Peebles, Sean A

    2008-02-21

    Rotational spectra for the normal and four isotopically substituted species of the 1:1 complex between methyl fluoride (H3CF) and carbonyl sulfide (OCS) have been measured using Fourier-transform microwave spectroscopy in the 5-16 GHz frequency region. The observed spectra fit well to a semirigid Watson Hamiltonian, and an analysis of the rotational constants has allowed a structure to be determined for this complex. The dipole moment vectors of the H3CF and OCS monomers are aligned approximately antiparallel with a C...C separation of 3.75(3) A and with an ab plane of symmetry. The values of the Pcc planar moments were found to be considerably different from the expected rigid values for all isotopologues. An estimate of approximately 14.5(50) cm-1 for the internal rotation barrier of the CH3 group with respect to the framework of the complex has been made using the Pcc values for the H3CF-OCS and D3CF-OCS isotopic species. Two structures, very close in energy and approximately related by a 60 degrees rotation about the C3 axis of the methyl fluoride, were identified by ab initio calculations at the MP2/6-311++G(2d,2p) level and provide reasonable agreement with the experimental rotational constants and dipole moment components.

  20. Recovery of metal chlorides from their complexes by molten salt displacement

    International Nuclear Information System (INIS)

    McLaughlin, D.F.; Stoltz, R.A.

    1989-01-01

    This patent describes a process for recovering zirconium or hafnium chloride from a complex of zirconium or hafnium tetrachloride and phosphorus oxychloride. The process comprising: introducing liquid complex of zirconium or hafnium tetrachloride and phosphorus oxychloride into an upper portion of a feed column containing zirconium or hafnium tetrachloride vapor and phosphorus oxychloride vapor. The liquid complex absorbing zirconium or hafnium tetrachloride vapor and producing a bottoms liquid and also producing a phosphorus oxychloride vapor stripped of zirconium or hafnium tetrachloride; introducing the bottoms liquid into a molten salt containing displacement reactor, the reactor containing molten salt comprising at least 30 mole percent lithium chloride and at least 30 mole percent of at least one other alkali metal chloride, the reactor being heated to 30-450 0 C to displace phosphorus oxychloride from the complex and product zirconium or hafnium tetrachloride vapor and phosphorus oxychloride vapor and zirconium or hafnium tetrachloride-containing molten salt; introducing the zirconium or hafnium tetrachloride vapor and the phosphorus oxychloride vapor into the feed column below the point of introduction of the liquid stream; introducing the zirconium or hafnium tetrachloride containing-molten salt into a recovery vessel where zirconium or hafnium tetrachloride is removed from the molten salt to produce zirconium or hafnium tetrachloride product and zirconium or hafnium chloride-depleted molten salt; and recycling the zirconium or hafnium tetachloride-depleted molten salt to the displacement reactor

  1. 3D Gravity Modeling of Complex Salt Features in the Southern Gulf of Mexico

    Directory of Open Access Journals (Sweden)

    Mauricio Nava-Flores

    2016-01-01

    Full Text Available We present a three-dimensional (3D gravity modeling and inversion approach and its application to complex geological settings characterized by several allochthonous salt bodies embedded in terrigenous sediments. Synthetic gravity data were computed for 3D forward modeling of salt bodies interpreted from Prestack Depth Migration (PSDM seismic images. Density contrasts for the salt bodies surrounded by sedimentary units are derived from density-compaction curves for the northern Gulf of Mexico’s oil exploration surveys. By integrating results from different shape- and depth-source estimation algorithms, we built an initial model for the gravity anomaly inversion. We then applied a numerically optimized 3D simulated annealing gravity inversion method. The inverted 3D density model successfully retrieves the synthetic salt body ensemble. Results highlight the significance of integrating high-resolution potential field data for salt and subsalt imaging in oil exploration.

  2. Fluoride-Salt-Cooled High-Temperature Reactor (FHR) with Silicon-Carbide-Matrix Coated-Particle Fuel

    International Nuclear Information System (INIS)

    Forsberg, C. W.; Snead, Lance Lewis; Katoh, Yutai

    2012-01-01

    The FHR is a new reactor concept that uses coated-particle fuel and a low-pressure liquid-salt coolant. Its neutronics are similar to a high-temperature gas-cooled reactor (HTGR). The power density is 5 to 10 times higher because of the superior cooling properties of liquids versus gases. The leading candidate coolant salt is a mixture of 7 LiF and BeF 2 (FLiBe) possessing a boiling point above 1300 C and the figure of merit ρC p (volumetric heat capacity) for the salt slightly superior to water. Studies are underway to define a near-term base-line concept while understanding longer-term options. Near-term options use graphite-matrix coated-particle fuel where the graphite is both a structural component and the primary neutron moderator. It is the same basic fuel used in HTGRs. The fuel can take several geometric forms with a pebble bed being the leading contender. Recent work on silicon-carbide-matrix (SiCm) coated-particle fuel may create a second longer-term fuel option. SiCm coated-particle fuels are currently being investigated for use in light-water reactors. The replacement of the graphite matrix with a SiCm creates a new family of fuels. The first motivation behind the effort is to take advantage of the superior radiation resistance of SiC compared to graphite in order to provide a stable matrix for hosting coated fuel particles. The second motivation is a much more rugged fuel under accident, repository, and other conditions.

  3. A general access to organogold(iii) complexes by oxidative addition of diazonium salts.

    Science.gov (United States)

    Huang, Long; Rominger, Frank; Rudolph, Matthias; Hashmi, A Stephen K

    2016-05-11

    At room temperature under mild photochemical conditions, namely irradiation with a simple blue light LED, gold(i) chloro complexes of both phosphane and carbene ligands in combination with aryldiazonium salts afford arylgold(iii) complexes. With chelating P,N-ligands cationic six- or five-membered chelate complexes were isolated in the form of salts with weakly coordinating counter anions that were brought in from the diazonium salt. With monodentate P ligands or N-heterocyclic carbene ligands and diazonium chlorides neutral arylgold(iii) dichloro complexes were obtained. The coordination geometry was determined by X-ray crystal structure analyses of representative compounds, a cis arrangement of the aryl and the phosphane ligand at the square planar gold(iii) center is observed.

  4. Influence of a solvent on thermodynamics of electrolytic dissociation of simple and complex rare earth salts

    Energy Technology Data Exchange (ETDEWEB)

    Gorodyskij, A.V.; Fialkov, Yu.Ya.; Chernyj, D.B. (AN Ukrainskoj SSR, Kiev. Inst. Obshchej i Neorganicheskoj Khimii; Kievskij Politekhnicheskij Inst. (Ukrainian SSR))

    1982-03-01

    Influence of the double mixed solvent on thermodynamic characteristics of ionic migration of lanthanum, neodymium, europium and dysprosium chlorides as well as their phenanthroline complexes is considered. Decrease of lambdasub(c) of simple and complex rare earth salts in the lanthanum, neodymium-europium-dysprosium series as explained by increase of solvation degree, associated with lanthanum compression. It is shown that increase of methanol or propanol content results in exothermicity decrease of the ionic migration process. The temperature constituents of enthalpy and entropy of dissociation of the simple and complex rare earth salts are presented.

  5. Increased water resistance of paper treated with amylose-fatty ammonium salt inclusion complexes

    Science.gov (United States)

    Amylose inclusion complexes were prepared from high amylose corn starch and the HCl salts of hexadecylamine and octadecylamine. Solutions of the complexes were applied to paper at concentrations of 2-4%. After the treated papers were dried, sodium hydroxide solution was applied to convert the adsorb...

  6. Stability constants of the fluoride complexes of actinides in aqueous solution and their correlation with fundamental properties

    International Nuclear Information System (INIS)

    Chaudhuri, N.K.; Sawant, R.M.

    1997-09-01

    Stability constants of the fluoride complexes of the actinides in different oxidation states measured by potentiometric method using fluoride ion selective electrode have been presented. Procedure and precautions required to overcome certain difficulties particular to actinide ions have been discussed. Literature data from various sources have been compiled. In order to have a reasonable comparison the stability constant (β 1 ) values obtained in diverse ionic strength media are converted to thermodynamic stability constant, β 1 0 , using Davies equation (a modification of Debye-Huckel equation). A correlation of the β 1 0 values with the fundamental properties of the actinide ions using various models available in the literature has been attempted. A semiempirical relation recently developed by Brown, Sylva and Ellis (BSE equation) appears to be most suitable. Using the values of ionic radii and best available values of the stability constants of a large number of metal ions from recent compilations a comparative study of the various models or relations available in the literature has been tried. For metal ions in general, the best correlation is obtained with the BSE equation. In an attempt to accommodate the unusual trend in the stability constants of the tetravalent actinides a modification in a parameter of the BSE equation has been proposed. Good agreement between the theoretically calculated and experimentally determined values for actinides in different oxidation states is then obtained in most of the cases. (author)

  7. Magnetic interactions through fluoride

    DEFF Research Database (Denmark)

    Pedersen, Kasper Steen; Sigrist, Marc; Weihe, Høgni

    2014-01-01

    support the parameter values and resolve |E| ≈ 0.04 cm(-1). The exchange coupling constant (J) is 1 order of magnitude smaller than that found in comparable systems with linear oxide bridging but comparable to typical magnitudes through cyanide, thus underlining the potential of fluoride complexes......The nature of the magnetic interaction through fluoride in a simple, dinuclear manganese(III) complex (1), bridged by a single fluoride ion in a perfectly linear fashion, is established by experiment and density functional theory. The magnitude of the antiferromagnetic exchange interaction...

  8. Electrochemical behaviours of lanthanide fluorides in the electrolysis system with LiF-NaF-Kf salt

    International Nuclear Information System (INIS)

    Joon-Bo, Shim; Sung-Chan, Hwang; Eung-Ho, Kim; Young-Ho, Kang; Byung-Jik, Lee; Jae-Hyung, Yoo

    2003-01-01

    As a part of partitioning studies, the experiments of cyclic voltammetry and electrolytic reduction with the liquid bismuth cathode were conducted to investigate electrochemical behaviours of lanthanide elements in the electrorefining system employing LiF-NaF-KF eutectic salt as the electrolyte. The cyclic voltammograms for NdF 3 and GdF 3 were obtained at various potential scan rates, respectively. The cathodic and anodic peak currents of the elements increased in proportion to the square root of the potential scan rate. According to changes of the potential difference between the coupled cathodic and anodic peaks, reversibilities of the reduction-oxidation reactions in this system were evaluated. In addition, further behaviours of electrochemical reaction of the elements were examined through electrolytic tests of the system using liquid bismuth as the cathode at fixed current densities. (author)

  9. The Effect of Salt on the Complex Coacervation of Vinyl Polyelectrolytes

    Directory of Open Access Journals (Sweden)

    Sarah L. Perry

    2014-06-01

    Full Text Available Complex coacervation is an electrostatically-driven phase separation phenomenon that is utilized in a wide range of everyday applications and is of great interest for the creation of self-assembled materials. Here, we utilized turbidity to characterize the effect of salt type on coacervate formation using two vinyl polyelectrolytes, poly(acrylic acid sodium salt (pAA and poly(allylamine hydrochloride (pAH, as simple models for industrial and biological coacervates. We confirmed the dominant role of salt valence on the extent of coacervate formation, while demonstrating the presence of significant secondary effects, which can be described by Hofmeister-like behavior. These results revealed the importance of ion-specific interactions, which are crucial for the informed design of coacervate-based materials for use in complex ionic environments, and can enable more detailed theoretical investigations on the role of subtle electrostatic and thermodynamic effects in complex coacervation.

  10. The Effect of Salt on the Complex Coacervation of Vinyl Polyelectrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Perry, Sarah; Li, Yue; Priftis, Dimitrios; Leon, Lorraine; Tirrell, Matthew

    2014-06-01

    Complex coacervation is an electrostatically-driven phase separation phenomenon that is utilized in a wide range of everyday applications and is of great interest for the creation of self-assembled materials. Here, we utilized turbidity to characterize the effect of salt type on coacervate formation using two vinyl polyelectrolytes, poly(acrylic acid sodium salt) (pAA) and poly(allylamine hydrochloride) (pAH), as simple models for industrial and biological coacervates. We confirmed the dominant role of salt valence on the extent of coacervate formation, while demonstrating the presence of significant secondary effects, which can be described by Hofmeister-like behavior. These results revealed the importance of ion-specific interactions, which are crucial for the informed design of coacervate-based materials for use in complex ionic environments, and can enable more detailed theoretical investigations on the role of subtle electrostatic and thermodynamic effects in complex coacervation.

  11. Chemical dissolution of spent fuel and cladding using complexed fluoride species

    International Nuclear Information System (INIS)

    Rance, P.J.W.; Freeman, G.A.; Mishin, V.; Issoupov, V.

    2001-01-01

    The dissolution of LWR fuel cladding using two fluoride ion donors, HBF 4 and K 2 ZrF 6 , in combination with nitric acid has been investigated as a potential reprocessing head-end process suitable for chemical decladding and fuel dissolution in a single process step. Maximum zirconium concentrations in the order of 0,75 to 1 molar have been achieved and dissolution found to continue to low F:Zr ratios albeit at ever decreasing rates. Dissolution rates of un-oxidised zirconium based fuel claddings are fast, whereas oxidised materials exhibit an induction period prior to dissolution. Data is presented relating to the rates of dissolution of cladding and UO 2 fuels under various conditions. (author)

  12. Investigation of holmium(5) complexing in hydrofluoric acid solutions in the presence of alkali metal and ammonium fluorides

    International Nuclear Information System (INIS)

    Tsikaeva, D.V.; Agulyanskij, A.I.; Balabanov, Yu.I.; Kuznetsov, V.Ya.; Kalinnikov, V.T.

    1989-01-01

    Method of vibrational spectroscopy is used to study niobium-containing solutions of hydrofluoric acid in the presence of alkali metal and ammonium fluorides. It is shown that NbF 6 - and NbOF 5 2- ions co-exists in solutions, therewith, additions shift equilibrium to the second complex side. Methods of IR spectroscopy, roentgenometry, crystal optics and chemical analysis are used to identify precipitated from solutions solid phases. Three new phases, which composition by chemical analysis corresponds to M 3 Nb 2 OF 11 , where M=NH 4 , K, Rb, are detected. Their roentgenometric data displayed in tetragonal crystal system with a and c parameters equalling 15,710 and 7,744; 14,877 and 7,697; 15,511 and 7,785 A respectively, are presented

  13. Pebble Bed Reactors Design Optimization Methods and their Application to the Pebble Bed Fluoride Salt Cooled High Temperature Reactor (PB-FHR)

    Science.gov (United States)

    Cisneros, Anselmo Tomas, Jr.

    The Fluoride salt cooled High temperature Reactor (FHR) is a class of advanced nuclear reactors that combine the robust coated particle fuel form from high temperature gas cooled reactors, direct reactor auxillary cooling system (DRACS) passive decay removal of liquid metal fast reactors, and the transparent, high volumetric heat capacitance liquid fluoride salt working fluids---flibe (33%7Li2F-67%BeF)---from molten salt reactors. This combination of fuel and coolant enables FHRs to operate in a high-temperature low-pressure design space that has beneficial safety and economic implications. In 2012, UC Berkeley was charged with developing a pre-conceptual design of a commercial prototype FHR---the Pebble Bed- Fluoride Salt Cooled High Temperature Reactor (PB-FHR)---as part of the Nuclear Energy University Programs' (NEUP) integrated research project. The Mark 1 design of the PB-FHR (Mk1 PB-FHR) is 236 MWt flibe cooled pebble bed nuclear heat source that drives an open-air Brayton combine-cycle power conversion system. The PB-FHR's pebble bed consists of a 19.8% enriched uranium fuel core surrounded by an inert graphite pebble reflector that shields the outer solid graphite reflector, core barrel and reactor vessel. The fuel reaches an average burnup of 178000 MWt-d/MT. The Mk1 PB-FHR exhibits strong negative temperature reactivity feedback from the fuel, graphite moderator and the flibe coolant but a small positive temperature reactivity feedback of the inner reflector and from the outer graphite pebble reflector. A novel neutronics and depletion methodology---the multiple burnup state methodology was developed for an accurate and efficient search for the equilibrium composition of an arbitrary continuously refueled pebble bed reactor core. The Burnup Equilibrium Analysis Utility (BEAU) computer program was developed to implement this methodology. BEAU was successfully benchmarked against published results generated with existing equilibrium depletion codes VSOP

  14. Infrared studies on complexes between octaethyltetraamidepyrophosphate (OETAPP) and uranyl salts

    International Nuclear Information System (INIS)

    Grychowski, P.; Mikulski, J.; Moravets, Ya.; Shara, V.; Shourkova, L.

    1981-01-01

    Uranyl nitrate and uranyl chloride were extracted from the water phase with CHCl 3 solution of octaethyltetraamidepyrophosphate (OETAPP). Infrared spectra of the organic phases were recorded before and after the extraction. For both systems, the frequency of the P=O stretching mode of OETAPP after the extraction was lowered, which indicates for the formation of OETAPP UO 2 (NO 3 ) 2 and OETAPP UO 2 Cl 2 complexes. If uranyl nitrate was extracted with OETAPP in CCl 4 a precipitate was formed in the solution. From the analysis of the IR spectrum of the precipitate it was concluded that the complex OETAPP UO 2 (NO 3 ) 2 was formed also in this case, however, the complex was insoluble in CCl 4 . (author)

  15. Visualization of Fluoride Ions In Vivo Using a Gadolinium(III)-Coumarin Complex-Based Fluorescence/MRI Dual-Modal Probe.

    Science.gov (United States)

    Wang, Yue; Song, Renfeng; Feng, Huan; Guo, Ke; Meng, Qingtao; Chi, Haijun; Zhang, Run; Zhang, Zhiqiang

    2016-12-16

    A new Gadolinium(III)-coumarin complex, DO3A-Gd- CA , was designed and prepared as a dual-modal probe for simultaneous fluorescence and relaxivity responses to fluoride ions (F - ) in aqueous media and mice. DO3A-Gd- CA was designed by using Gd(III) center as an MRI signal output unit and fluoride binding site, and the 4-(diethylamino)-coumarin-3-carboxylic acid ( CA ) as a fluorescence reporter. Upon the addition of fluoride ions to the solution of DO3A-Gd- CA , the liberation of the coordinated CA ligand led to a 5.7-fold fluorescence enhancement and a 75% increase in the longitudinal relaxivity ( r ₁). The fluorescent detection limit for fluoride ions was determined to be 8 μM based on a 3 σ / slope . The desirable features of the proposed DO3A-Gd- CA , such as high sensitivity and specificity, reliability at physiological pH and low cytotoxicity enable its application in visualization of fluoride ion in mice. The successful in vivo imaging indicates that DO3A-Gd- CA could be potentially used in biomedical diagnosis fields.

  16. Rare Earth Electrochemical Property Measurements and Phase Diagram Development in a Complex Molten Salt Mixture for Molten Salt Recycle

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jinsuo; Guo, Shaoqiang

    2018-03-30

    Pyroprocessing is a promising alternative for the reprocessing of used nuclear fuel (UNF) that uses electrochemical methods. Compared to the hydrometallurgical reprocessing method, pyroprocessing has many advantages such as reduced volume of radioactive waste, simple waste processing, ability to treat refractory material, and compatibility with fast reactor fuel recycle. The key steps of the process are the electro-refining of the spent metallic fuel in the LiCl-KCl eutectic salt, which can be integrated with an electrolytic reduction step for the reprocessing of spent oxide fuels. During the electro-refining process, actinides and active fission products such rare earth (RE) elements are dissolved into the molten salt from the spent fuel at an anode basket. Then U and Pu are electro-deposited on the cathodes while REs with relatively negative reduction potentials are left in the molten salt bath. However, with the accumulation of lanthanides in the salt, the reduction potentials of REs will approach the values for U and Pu, affecting the recovery efficiency of U and Pu. Hence, RE drawdown is necessary to reduce salt waste after uranium and minor actinides recovery, which can also be performed by electrochemical separations. To separate various REs and optimize the drawdown process, physical properties of REs in LiCl-KCl salt and their concentration dependence are essential. Thus, the primary goal of present research is to provide fundamental data of REs and deduce phase diagrams of LiCl-KCl-RECl3 based complex molten salts. La, Nd and Gd are three representative REs that we are particularly interested in due to the high ratio of La and Nd in UNF, highest standard potential of Gd among all REs, and the existing literature data in dilute solution. Electrochemical measurements are performed to study the thermodynamics and transport properties of LaCl3, GdCl3, NdCl3, and NdCl2 in LiCl-KCl eutectic in the temperature range 723-823 K. Test are conducted in LiCl-KCl melt

  17. Heat transfer measurements in a forced convection loop with two molten-fluoride salts: LiF--BeF2--ThF2--UF4 and eutectic NaBF4--NaF

    International Nuclear Information System (INIS)

    Silverman, M.D.; Huntley, W.R.; Robertson, H.E.

    1976-10-01

    Heat transfer coefficients were determined experimentally for two molten-fluoride salts [LiF-BeF 2 -ThF 2 -UF 4 (72-16-12-0.3 mole %) and NaBF 4 -NaF (92-8 mole %] proposed as the fuel salt and coolant salt, respectively, for molten-salt breeder reactors. Information was obtained over a wide range of variables, with salt flowing through 12.7-mm-OD (0.5-in.) Hastelloy N tubing in a forced convection loop (FCL-2b). Satisfactory agreement with the empirical Sieder-Tate correlation was obtained in the fully developed turbulent region at Reynolds moduli above 15,000 and with a modified Hausen equation in the extended transition region (Re approx.2100-15,000). Insufficient data were obtained in the laminar region to allow any conclusions to be drawn. These results indicate that the proposed salts behave as normal heat transfer fluids with an extended transition region

  18. Speciation of cadmium mixed ligand complexes in salt water lakes

    Directory of Open Access Journals (Sweden)

    John L. Kituyi

    2003-06-01

    Full Text Available Amalgam voltammetry has been used to study heavy metal interaction in model lake water in KNO3 at 23 oC at concentration levels of genuine lake water. The hanging drop amalgam electrode was prepared in situ before exchanging the medium for the sample solution. Half-wave potentials at two metal ion concentrations were measured, one at the actual concentration in the lake while the other at a much lower one. The experimentally determined shifts in half-wave potentials are used to compute several formation constants. At the natural [CO32-] of 0.5 M in the lake, the main contributor to the speciation of cadmium is [Cd(CO3Cl2]2-. At high [Cd2+], the DPASV detects the presence of free Cd2+ ions, hence, potential polluting effect, while the amalgam reports [Cd(CO32Cl] 3- to be dominant above [CO32-] = 0.8 M. There is a variation in the number of complexes detected, their stabilities and percentage distribution in the two methods. Cd2+ ion concentration also affects the number of complexes formed and their stabilities.

  19. Complexation and sensing behavior of dansyl-appended cyclodextrins and cyclodextrin dimers with bile salts

    NARCIS (Netherlands)

    Jong, de M.R.; Berthault, P.; Hoek, van A.; Visser, A.J.W.G.; Huskens, J.; Reinhoudt, D.N.

    2002-01-01

    The dansyl-modified cyclodextrin derivatives 2 and 3 form complexes with the steroidal bile salts. The selectivity of the monomeric derivative 3 is similar to that of native g-cyclodextrin. All binding constants with 3 are lowered compared to g-cyclodextrin because of the competition for the cavity

  20. Complexation and sensing behavior of dansyl-appended cyclodextrins and cyclodextrin dimers with bile salts

    NARCIS (Netherlands)

    de Jong, M.R.; Berthault, Patrick; van Hoek, Arie; Visser, Antonie J.W.G.; Huskens, Jurriaan; Reinhoudt, David

    2002-01-01

    The dansyl-modified cyclodextrin derivatives 2 and 3 form complexes with the steroidal bile salts. The selectivity of the monomeric derivative 3 is similar to that of native β-cyclodextrin. All binding constants with 3 are lowered compared to β-cyclodextrin because of the competition for the cavity

  1. Thermodynamic characterization of salt components for the Molten Salt Reactor Fuel - 15573

    International Nuclear Information System (INIS)

    Capelli, E.; Konings, R.J.M.; Benes, A.

    2015-01-01

    Molten fluoride salts are considered as primary candidates for nuclear fuel in the Molten Salt Reactor (MSR), one of the 6 generation IV nuclear reactor designs. In order to determine the safety limits and to access the properties of the potential fuel mixtures, thermodynamic studies are very important. This study is a combination of experimental work and thermodynamic modelling and focusses on the fluoride systems with alkaline and alkaline earth fluorides as matrix and ThF 4 , UF 4 and PuF 3 as fertile and fissile materials. The purification of the single components was considered as essential first step for the study of more complex systems and ternary phase diagrams were described using Differential Scanning Calorimetry (DSC) and drop calorimetry, which are used to measure phase transitions, enthalpy of mixing and heat capacity. In addition to the calorimetric techniques, Knudsen Effusion Mass Spectrometry (KEMS) and X-ray Diffraction (XRD) were used to collect data on vapour pressure and crystal structure of fluorides. The results are then coupled with thermodynamic modelling using the Calphad method for the assessment of the phase diagrams. A thermodynamic database describing the most important systems for MSR application has been developed and it has been used to optimize the fuel composition in view of the relevant properties such as melting temperature. A reliable database of thermodynamic properties of fluoride salts has been generated. It includes the key systems for the MSR fuel and it is very useful to predict the properties of the fuel

  2. Synthesis of an oxo trialkyl tungsten fluoride complex and its dual reactivity with silica dehydroxylated at high temperature

    KAUST Repository

    Merle, Nicolas

    2018-05-22

    The novel complex W (=O)Np3F has been prepared by fluorination of the corresponding chloride counterpart with AgBF4. The reactivity of this complex with silica dehydroxylated at 700 °C afforded a well-defined silica supported monopodal tungsten oxo trialkyl surface species (≡SiO)W (=O)Np3. The reaction proceeds both through silanolysis of the W-F bond and opening of a siloxane bridge, with formation of a Si-F fragment, thanks to the affinity of silicon for fluoride. The resulting surface species was characterized by elemental analysis, DRIFT, solid state NMR and EXAFS spectroscopy. This material presenting fluorine on its surface shows an enhanced catalytic activity in propylene self-metathesis compared to its monopodal counterpart (≡SiO)W (=O)Np3 (prepared from W (=O)Np3Cl) suggesting that the Si-F in a close vicinity to the W decreases the electron density of the W and thus increases its reactivity towards the olefinic substrate.

  3. Synthesis of an oxo trialkyl tungsten fluoride complex and its dual reactivity with silica dehydroxylated at high temperature

    KAUST Repository

    Merle, Nicolas; Mazoyer, Etienne; Szeto, Kai C.; Rouge, Pascal; de Mallmann, Aimery; Berrier, Elise; Delevoye, Laurent; Gauvin, Ré gis M.; Nicholas, Christopher P.; Basset, Jean-Marie; Taoufik, Mostafa

    2018-01-01

    The novel complex W (=O)Np3F has been prepared by fluorination of the corresponding chloride counterpart with AgBF4. The reactivity of this complex with silica dehydroxylated at 700 °C afforded a well-defined silica supported monopodal tungsten oxo trialkyl surface species (≡SiO)W (=O)Np3. The reaction proceeds both through silanolysis of the W-F bond and opening of a siloxane bridge, with formation of a Si-F fragment, thanks to the affinity of silicon for fluoride. The resulting surface species was characterized by elemental analysis, DRIFT, solid state NMR and EXAFS spectroscopy. This material presenting fluorine on its surface shows an enhanced catalytic activity in propylene self-metathesis compared to its monopodal counterpart (≡SiO)W (=O)Np3 (prepared from W (=O)Np3Cl) suggesting that the Si-F in a close vicinity to the W decreases the electron density of the W and thus increases its reactivity towards the olefinic substrate.

  4. Effect of bisquaternary ammonium salts on complexing of metal ions with pyrocatechol violet

    International Nuclear Information System (INIS)

    Tananajko, M.M.; Kofanova, N.K.

    1984-01-01

    Conditions for the improvement of contrast and sensitivity of reactions of high-charge ions of metals (Mo, W, La, Cd, Zr, Hf, Th) in the process of their photometric determination with pyrocatechol violet (PV), using bisquaternary ammonium salts (BQAS), have been studied. It is shown that in the systems investigated the BQAS play the role of ''shifting'' reagents, shifting bathochromically the absorption bands of different ligand complexes as compared with absorption bands of the Me-PV binary complexes. The effect of the BQAS on complexing with PV in aqueous and organic phases (chloroform) is studied and potential flotation of the compounds in the phase interface is considered

  5. In vitro studies on interactions of iron salts and complexes with food-stuffs and medicaments.

    Science.gov (United States)

    Geisser, P

    1990-07-01

    It has been shown in the present study that food components such as phytic acid, oxalic acid, tannin, sodium alginate, choline and choline salts, vitamins A, D3 and E, soy oil and soy flour, do not undergo any interactions with iron(III)-hydroxide polymaltose complex (Ferrum Hausmann). Phytic acid, oxalic acid, tannin and sodium alginate, however, react with iron(II) or iron(III)-salts at pH values of 3.0, 5.5 and 8.0, giving rise to iron complexes. Trimethylamine-N-oxide, which is present in fish meal, reacts with iron(II)-sulphate to produce iron(III) reaction products; it does not react with iron(III)-hydroxide polymaltose complex. Special soybean flours show no irreversible adsorption or precipitation with iron(III)-hydroxyide polymaltose complex over the pH range 3.0-8.0, in contrast to iron(II)-sulphate. Antacids containing aluminium hydroxide, talc, ion exchange resins or other unabsorbable, insoluble components absorb iron(III)-hydroxide polymaltose complex in the pH range 3.0-8.0 in a reversible manner, while the strong adsorption or precipitation observed with iron(II)-sulphate at pH 8.0 is irreversible. No interaction was observed between the steroid hormones studied and iron(II)-sulphate or iron(III)-hydroxide polymaltose complex. On the basis of the measured compatibilities, iron(III)-hydroxide polymaltose complex can be administered orally simultaneously with many other drugs, without prejudicing the absorption of iron or of the other drug as is often seen with iron(II) and iron(III) salts.

  6. Utilizing the σ-complex stability for quantifying reactivity in nucleophilic substitution of aromatic fluorides

    Directory of Open Access Journals (Sweden)

    Magnus Liljenberg

    2013-04-01

    Full Text Available A computational approach using density functional theory to compute the energies of the possible σ-complex reaction intermediates, the “σ-complex approach”, has been shown to be very useful in predicting regioselectivity, in electrophilic as well as nucleophilic aromatic substitution. In this article we give a short overview of the background for these investigations and the general requirements for predictive reactivity models for the pharmaceutical industry. We also present new results regarding the reaction rates and regioselectivities in nucleophilic substitution of fluorinated aromatics. They were rationalized by investigating linear correlations between experimental rate constants (k from the literature with a theoretical quantity, which we call the sigma stability (SS. The SS is the energy change associated with formation of the intermediate σ-complex by attachment of the nucleophile to the aromatic ring. The correlations, which include both neutral (NH3 and anionic (MeO− nucleophiles are quite satisfactory (r = 0.93 to r = 0.99, and SS is thus useful for quantifying both global (substrate and local (positional reactivity in SNAr reactions of fluorinated aromatic substrates. A mechanistic analysis shows that the geometric structure of the σ-complex resembles the rate-limiting transition state and that this provides a rationale for the observed correlations between the SS and the reaction rate.

  7. Interaction of cesium ions with calix[2]furan[4]pyrrole and its fluoride complex

    Czech Academy of Sciences Publication Activity Database

    Kříž, Jaroslav; Dybal, Jiří; Makrlík, E.; Kohnke, F. H.

    2012-01-01

    Roč. 541, 10 July (2012), s. 27-31 ISSN 0009-2614 Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : calix[2]furan[4]pyrrole * Cs complex * NMR Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.145, year: 2012

  8. Synthesis of complex oxides with garnet structure by spray drying of an aqueous salt solution

    Science.gov (United States)

    Makeenko, A. V.; Larionova, T. V.; Klimova-Korsmik, O. G.; Starykh, R. V.; Galkin, V. V.; Tolochko, O. V.

    2017-04-01

    The use of spray drying to obtain powders of complex oxides with a garnet structure has demonstrated. The processes occurring during heating of the synthesized oxide-salt product, leading to the formation of a material with a garnet structure, have been investigated using DTA, TGA, XPS, and XRD. It has been shown that a single-phase garnet structure of system (Y x Gd(3- x))3Al5O12 can be synthesized over the entire range of compositions.

  9. Bile salt receptor complex activates a pathogenic type III secretion system

    Science.gov (United States)

    Li, Peng; Rivera-Cancel, Giomar; Kinch, Lisa N; Salomon, Dor; Tomchick, Diana R; Grishin, Nick V; Orth, Kim

    2016-01-01

    Bile is an important component of the human gastrointestinal tract with an essential role in food absorption and antimicrobial activities. Enteric bacterial pathogens have developed strategies to sense bile as an environmental cue to regulate virulence genes during infection. We discovered that Vibrio parahaemolyticus VtrC, along with VtrA and VtrB, are required for activating the virulence type III secretion system 2 in response to bile salts. The VtrA/VtrC complex activates VtrB in the presence of bile salts. The crystal structure of the periplasmic domains of the VtrA/VtrC heterodimer reveals a β-barrel with a hydrophobic inner chamber. A co-crystal structure of VtrA/VtrC with bile salt, along with biophysical and mutational analysis, demonstrates that the hydrophobic chamber binds bile salts and activates the virulence network. As part of a family of conserved signaling receptors, VtrA/VtrC provides structural and functional insights into the evolutionarily conserved mechanism used by bacteria to sense their environment. DOI: http://dx.doi.org/10.7554/eLife.15718.001 PMID:27377244

  10. Bile salt receptor complex activates a pathogenic type III secretion system

    Energy Technology Data Exchange (ETDEWEB)

    Li, Peng; Rivera-Cancel, Giomar; Kinch, Lisa N.; Salomon, Dor; Tomchick, Diana R.; Grishin, Nick V.; Orth, Kim

    2016-07-05

    Bile is an important component of the human gastrointestinal tract with an essential role in food absorption and antimicrobial activities. Enteric bacterial pathogens have developed strategies to sense bile as an environmental cue to regulate virulence genes during infection. We discovered thatVibrio parahaemolyticusVtrC, along with VtrA and VtrB, are required for activating the virulence type III secretion system 2 in response to bile salts. The VtrA/VtrC complex activates VtrB in the presence of bile salts. The crystal structure of the periplasmic domains of the VtrA/VtrC heterodimer reveals a β-barrel with a hydrophobic inner chamber. A co-crystal structure of VtrA/VtrC with bile salt, along with biophysical and mutational analysis, demonstrates that the hydrophobic chamber binds bile salts and activates the virulence network. As part of a family of conserved signaling receptors, VtrA/VtrC provides structural and functional insights into the evolutionarily conserved mechanism used by bacteria to sense their environment.

  11. Fluoride analysis

    Energy Technology Data Exchange (ETDEWEB)

    Brandt, C S

    1963-01-01

    The methods and procedures for the detection and estimation of fluoride are varied and numerous. The problems of sampling, contamination, and loss in sampling waters, plant and animal tissues and atmospheres are discussed, along with brief descriptors of methods most commonly used. Techniques for separating fluorides from matrixes are discussed, as well as gravimetric, calorimetric, and spectrophotometric analytical techniques.

  12. FUNCTION OF MALATDEHYDROGENASE COMPLEX OF MAIZE MESOPHYLL AND BUNDLE SHEATH CELLS UNDER SALT STRESS CONDITION

    Directory of Open Access Journals (Sweden)

    Еprintsev А.Т.

    2006-12-01

    Full Text Available Salt-induced changes in malatdehydrogenase system activity make the essential contribution to cell adaptation to stress condition. The enzyme systems of C4-plants are most interesting due to their ability for adaptation to environment conditions. The role of separate components of malatdehydrogenase complex of mesophyll and bundle sheath cells of corn in formation of adaptive reaction in stressful conditions is investigated in presented work.The activation of all enzymes of malatdehydrogenase system and the subsequent decrease in their activity was observed in mesophyll durring the first stage of adaptation to salt influence. In bundle sheath cells such parameters are differed from control less essentially. Fast accumulation of piruvate in cells and malate in both investigated tissues was induced. The further salinity led to falling of concentration this intermediate. The concentration of piruvate was below control level, and it was raised by the end of an exposition.The results show that sodium chloride causes induction of Krebs-cycle in mesophyll and bundle sheath cells of corn and intensification of Hatch-Slack cycle. The described differences in function malatdehydrogenase systems of mesophyll and bundle sheath cells of leaves of corn under salinity mainly consist of the activity of enzymes of a studied complex in bundle sheath cells is subject to the minimal changes in comparison with mesophyll. Role of this enzymesystem in mechanisms of adaptive reaction of various tissues of corn to salt stress is discussed.

  13. Corrosion of oxide dispersion strengthened iron–chromium steels and tantalum in fluoride salt coolant: An in situ compatibility study for fusion and fusion–fission hybrid reactor concepts

    International Nuclear Information System (INIS)

    El-Dasher, Bassem; Farmer, Joseph; Ferreira, James; Serrano de Caro, Magdalena; Rubenchik, Alexander; Kimura, Akihiko

    2011-01-01

    Highlights: ► ODS steel corrosion in molten fluoride salts was studied in situ using electrochemical impedance spectroscopy. ► Steel/coolant interfacial resistance increases from 600 to 800 °C due to an aluminum enriched layer forming at the surface. ► The addition of tungsten to ODS steels increases corrosion resistance measurably at 600 °C. - Abstract: Primary candidate classes of materials for future nuclear power plants, whether they be fission, fusion or hybrids, include oxide dispersion strengthened (ODS) ferritic steels which rely on a dispersion of nano-oxide particles in the matrix for both mechanical strength and swelling resistance, or tantalum alloys which have an inherent neutron-induced swelling resistance and high temperature strength. For high temperature operation, eutectic molten lithium containing fluoride salts are attractive because of their breeding capability as well as their relatively high thermal capacity, which allow for a higher average operating temperature that increases power production. In this paper we test the compatibility of Flinak (LiF–NaF–KF) salts on ODS steels, comparing the performance of current generation ODS steels developed at Kyoto University with the commercial alloy MA956. Pure tantalum was also tested for comparative purposes. In situ data was obtained for temperatures ranging from 600 to 900 °C using a custom-built high temperature electrochemical impedance spectroscopy cell. Results for ODS steels show that steel/coolant interfacial resistance increases from 600 to 800 °C due to an aluminum enriched layer forming at the surface, however an increase in temperature to 900 °C causes this layer to break up and aggressive attack to occur. Performance of current generation ODS steels surpassed that of the MA956 ODS steel, with an in situ impedance behavior similar or better than that of pure tantalum.

  14. Complexes with charge transfer and ion-radical salts in catalysis

    Energy Technology Data Exchange (ETDEWEB)

    Krylov, O V [AN SSSR, Moscow. Inst. Khimicheskoj Fiziki

    1978-01-01

    Considered are the data experimentally proving formation of complexes with charge transfer as intermediate complexes in homogeneous and heterogeneous catalysis. Catalytic activity correlations with charge transfer energy (and in heterogeneous catalysis with width of semiconductor forbidden band can be useful while selection of catalysts (MoO/sub 3//MgO; V/sub 2/O/sub 5//MgO; MoO/sub 3//Al/sub 2/O/sub 3/; V/sub 2/O/sub 5//Al/sub 2/O/sub 3/). A review of papers on catalytic activity of the previously prepared complexes with charge transfer and ion-radical salts is given. The use of alkali metal complexes with aromatic compounds showed their high activity in hydrogenation reactions and proved principle possibility of activation of hydrogen and hydrocarbons by the systems which do not contain transfer metals.

  15. Formation and stabilization of anionic metal complexes in concentrated aqueous quaternary ammonium salt solutions

    International Nuclear Information System (INIS)

    Aronson, F.L.; Hwang, L.L.Y.; Ronca, N.; Solomon, N.A.; Steigman, J.

    1985-01-01

    Anionic complexes of transition metals were stabilized in aqueous solutions containing high concentrations of various short-chain quaternary ammonium salts. Compounds with longer paraffin chains were effective in much less concentrated solution. Complex ions were detected spectrophotometrically. FeCl 4 - , which is usually formed in concentrated HCl, was the predominant Fe(III) complex in 30 m choline chloride containing only 0.12 M HCl. A yellow transitory Tc(VII) chloro-addition intermediate, formed in the reduction of TcO 4 - by concentrated HCl, was stabilized when the solution also contained 25 m choline chloride. Its spectrum, as well as the isolation of an already known Tc(VII) bipyridyl complex, is reported. Concentrated organic electrolytes also stabilized Tc(V) oxide halides against disproportionation and Tc(IV) hexahalides against hydrolysis. Halochromates of Cr(VI) were formed and stabilized in dilute acid containing quaternary ammonium salts. Their UV spectra showed the well-resolved vibronic fine structure associated with the symmetric chromium-to-oxygen charge-transfer band. It is known that these progressions are resolved in aprotic solvents, but not in aqueous acidic solution alone, and that the loss of fine structure in aqueous media is due to hydrogen bonding. The stabilization of anionic metal complexes and the resolution of vibronic structure in halochromates are probably consequences of water-structure-enforced ion paring. The present work suggests that the water molecules in immediate contact with the complex anions are more strongly hydrogen bonded to each other than to the complex. 21 references, 4 figures

  16. Purification method for calcium fluoride containing uranium

    International Nuclear Information System (INIS)

    Ogami, Takeshi

    1998-01-01

    Calcium fluoride (CaF 2 ) containing uranium is heated in an electrolytic bath having a cathode and an anode to form a molten salt, and the molten salt is electrolytically reduced to form metal uranium deposited on the surface of the cathode. The calcium fluoride molten salt separated by the deposition of generated metal uranium on the surface of the cathode is solidified by cooling. The solidified calcium fluoride is recovered. When metal uranium is deposited on the surface of the cathode by the electrolytic reduction of the molten salt, impurities such as plutonium and neptunium are also deposited on the surface of the anodes entrained by the metal uranium. Impurities having high vapor pressures such as americium and strontium are evaporated and removed from the molten salts. Then, nuclides such as uranium can thus be separated and recovered, and residual CaF 2 can be recovered in a state easily storable and reutilizable. (T.M.)

  17. Complexation of Polyelectrolytes with Hydrophobic Drug Molecules in Salt-Free Solution: Theory and Simulations.

    Science.gov (United States)

    Lei, Qun-Li; Hadinoto, Kunn; Ni, Ran

    2017-04-18

    The delivery and dissolution of poorly soluble drugs is challenging in the pharmaceutical industry. One way to significantly improve the delivery efficiency is to incorporate these hydrophobic small molecules into a colloidal polyelectrolyes(PE)-drug complex in their ionized states. Despite its huge application value, the general mechanism of PE collapse and complex formation in this system has not been well understood. In this work, by combining a mean-field theory with extensive molecular simulations, we unveil the phase behaviors of the system under dilute and salt-free conditions. We find that the complexation is a first-order-like phase transition triggered by the hydrophobic attraction between the drug molecules. Importantly, the valence ratio between the drug molecule and PE monomer plays a crucial role in determining the stability and morphology of the complex. Moreover, the sign of the zeta potential and the net charge of the complex are found to be inverted as the hydrophobicity of the drug molecules increases. Both theory and simulation indicate that the complexation point and complex morphology and the electrostatic properties of the complex have a weak dependence on chain length. Finally, the dynamics aspect of PE-drug complexation is also explored, and it is found that the complex can be trapped into a nonequilibrium glasslike state when the hydropobicity of the drug molecule is too strong. Our work gives a clear physical picture behind the PE-drug complexation phenomenon and provides guidelines to fabricate the colloidal PE-drug complex with the desired physical characteristics.

  18. Density functional theory study on aqueous aluminum-fluoride complexes: exploration of the intrinsic relationship between water-exchange rate constants and structural parameters for monomer aluminum complexes.

    Science.gov (United States)

    Jin, Xiaoyan; Qian, Zhaosheng; Lu, Bangmei; Yang, Wenjing; Bi, Shuping

    2011-01-01

    Density functional theory (DFT) calculation is carried out to investigate the structures, (19)F and (27)Al NMR chemical shifts of aqueous Al-F complexes and their water-exchange reactions. The following investigations are performed in this paper: (1) the microscopic properties of typical aqueous Al-F complexes are obtained at the level of B3LYP/6-311+G**. Al-OH(2) bond lengths increase with F(-) replacing inner-sphere H(2)O progressively, indicating labilizing effect of F(-) ligand. The Al-OH(2) distance trans to fluoride is longer than other Al-OH(2) distance, accounting for trans effect of F(-) ligand. (19)F and (27)Al NMR chemical shifts are calculated using GIAO method at the HF/6-311+G** level relative to F(H(2)O)(6)(-) and Al(H(2)O)(6)(3+) references, respectively. The results are consistent with available experimental values; (2) the dissociative (D) activated mechanism is observed by modeling water-exchange reaction for [Al(H(2)O)(6-i)F(i)]((3-i)+) (i = 1-4). The activation energy barriers are found to decrease with increasing F(-) substitution, which is in line with experimental rate constants (k(ex)). The log k(ex) of AlF(3)(H(2)O)(3)(0) and AlF(4)(H(2)O)(2)(-) are predicted by three ways. The results indicate that the correlation between log k(ex) and Al-O bond length as well as the given transmission coefficient allows experimental rate constants to be predicted, whereas the correlation between log k(ex) and activation free energy is poor; (3) the environmental significance of this work is elucidated by the extension toward three fields, that is, polyaluminum system, monomer Al-organic system and other metal ions system with high charge-to-radius ratio.

  19. Evidence of solvent-dependent complexation in non-ionic polymer-salt systems

    International Nuclear Information System (INIS)

    Hakem, I.F.; Lal, J.

    2002-01-01

    Small angle neutron scattering measurements have been performed on polyethylene oxide (PEO)-salt solutions. An attempt is made to characterize experimentally the scattering behavior of aqueous (D 2 O) polyethylene oxide and PEO-methanol solutions in the presence of potassium iodide (KI). In water solution, no interactions were observed with KI and PEO. However, in methanol a definite indication of complex formation was found. Addition of KI to a solution of PEO in methanol shows a large change in interchain interaction and chain conformation. (orig.)

  20. Fluoridation Basics

    Science.gov (United States)

    ... return on investment for community water fluoridation (including productivity losses) ranged from $4 in small communities of ... National Center for Chronic Disease Prevention and Health Promotion Email Recommend Tweet YouTube Instagram Listen Watch RSS ...

  1. Relaxation Behavior by Time-Salt and Time-Temperature Superpositions of Polyelectrolyte Complexes from Coacervate to Precipitate

    Directory of Open Access Journals (Sweden)

    Samim Ali

    2018-01-01

    Full Text Available Complexation between anionic and cationic polyelectrolytes results in solid-like precipitates or liquid-like coacervate depending on the added salt in the aqueous medium. However, the boundary between these polymer-rich phases is quite broad and the associated changes in the polymer relaxation in the complexes across the transition regime are poorly understood. In this work, the relaxation dynamics of complexes across this transition is probed over a wide timescale by measuring viscoelastic spectra and zero-shear viscosities at varying temperatures and salt concentrations for two different salt types. We find that the complexes exhibit time-temperature superposition (TTS at all salt concentrations, while the range of overlapped-frequencies for time-temperature-salt superposition (TTSS strongly depends on the salt concentration (Cs and gradually shifts to higher frequencies as Cs is decreased. The sticky-Rouse model describes the relaxation behavior at all Cs. However, collective relaxation of polyelectrolyte complexes gradually approaches a rubbery regime and eventually exhibits a gel-like response as Cs is decreased and limits the validity of TTSS.

  2. Liquid-liquid reductive extraction in molten fluoride salt/liquid aluminium as a core of process for the An/Ln group separation

    International Nuclear Information System (INIS)

    Conocar, O.

    2007-06-01

    This report concerns a pyrochemical process based on liquid-liquid extraction in a molten fluoride/liquid aluminium system as a core process for actinide (An)/lanthanide (Ln) group separation, studied at CEA. The basic and demonstrative experiments have established the feasibility of the An/Ln group separation in the molten fluoride/liquid aluminium system (U, Pu, Np, Am, Cm traces from Nd, Ce, Eu, Sm, Eu, La - An/Ln separation factors over 1000 - An recovery yield over 98 % in one batch). The main experimental efforts must now be targeted on the recovery of actinides from the Al matrix. A thermodynamic and bibliographical survey has been done. It shows that back-extraction in a molten chloride melt could be a promising technique for this purpose

  3. Liquid-liquid reductive extraction in molten fluoride salt/liquid aluminium as a core of process for the An/Ln group separation

    Energy Technology Data Exchange (ETDEWEB)

    Conocar, O

    2007-06-15

    This report concerns a pyrochemical process based on liquid-liquid extraction in a molten fluoride/liquid aluminium system as a core process for actinide (An)/lanthanide (Ln) group separation, studied at CEA. The basic and demonstrative experiments have established the feasibility of the An/Ln group separation in the molten fluoride/liquid aluminium system (U, Pu, Np, Am, Cm traces from Nd, Ce, Eu, Sm, Eu, La - An/Ln separation factors over 1000 - An recovery yield over 98 % in one batch). The main experimental efforts must now be targeted on the recovery of actinides from the Al matrix. A thermodynamic and bibliographical survey has been done. It shows that back-extraction in a molten chloride melt could be a promising technique for this purpose.

  4. Inhibition of Mammalian Target of Rapamycin Complex 1 Attenuates Salt-Induced Hypertension and Kidney Injury in Dahl Salt-Sensitive Rats.

    Science.gov (United States)

    Kumar, Vikash; Wollner, Clayton; Kurth, Theresa; Bukowy, John D; Cowley, Allen W

    2017-10-01

    The goal of the present study was to explore the protective effects of mTORC1 (mammalian target of rapamycin complex 1) inhibition by rapamycin on salt-induced hypertension and kidney injury in Dahl salt-sensitive (SS) rats. We have previously demonstrated that H 2 O 2 is elevated in the kidneys of SS rats. The present study showed a significant upregulation of renal mTORC1 activity in the SS rats fed a 4.0% NaCl for 3 days. In addition, renal interstitial infusion of H 2 O 2 into salt-resistant Sprague Dawley rats for 3 days was also found to stimulate mTORC1 activity independent of a rise of arterial blood pressure. Together, these data indicate that the salt-induced increases of renal H 2 O 2 in SS rats activated the mTORC1 pathway. Daily administration of rapamycin (IP, 1.5 mg/kg per day) for 21 days reduced salt-induced hypertension from 176.0±9.0 to 153.0±12.0 mm Hg in SS rats but had no effect on blood pressure salt sensitivity in Sprague Dawley treated rats. Compared with vehicle, rapamycin reduced albumin excretion rate in SS rats from 190.0±35.0 to 37.0±5.0 mg/d and reduced the renal infiltration of T lymphocytes (CD3 + ) and macrophages (ED1 + ) in the cortex and medulla. Renal hypertrophy and cell proliferation were also reduced in rapamycin-treated SS rats. We conclude that enhancement of intrarenal H 2 O 2 with a 4.0% NaCl diet stimulates the mTORC1 pathway that is necessary for the full development of the salt-induced hypertension and kidney injury in the SS rat. © 2017 American Heart Association, Inc.

  5. Diazonium salt derivatives of osmium bipyridine complexes: Electrochemical grafting and characterisation of modified surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Garrett, David J. [MacDiarmid Institute for Advanced Materials and Nanotechnology, Department of Chemistry, University of Canterbury, Private Bag 4800, Christchurch (New Zealand); Jenkins, Peter [School of Chemistry, National University of Ireland, Galway (Ireland); Polson, Matthew I.J. [Department of Chemistry, University of Canterbury, Private Bag 4800, Christchurch (New Zealand); Leech, Donal [School of Chemistry, National University of Ireland, Galway (Ireland); Baronian, Keith H.R. [School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch (New Zealand); Downard, Alison J., E-mail: alison.downard@canterbury.ac.n [MacDiarmid Institute for Advanced Materials and Nanotechnology, Department of Chemistry, University of Canterbury, Private Bag 4800, Christchurch (New Zealand)

    2011-02-01

    Osmium bipyridine complexes were directly grafted to carbon electrodes through electroreduction of the diazonium salts [Os(bpy-ph-N{sub 2}{sup +}){sub 3}](PF{sub 6}){sub 5} (1) and [Os(bpy-ph-N{sub 2}{sup +}){sub 2}Cl{sub 2}](PF{sub 6}){sub 2} (2). Growth of the films was not self-limiting as is usually found for grafting from diazonium salts. It appears that electron hopping through the bipyridine ligands of the immobilised complexes enables film growth to continue at a constant rate during grafting by potential cycling. The surface concentrations of deposited films were measured electrochemically and the film thicknesses were measured by depth-profiling using the atomic force microscope. Films up to 42 nm thick were prepared with no evidence for slowing of film growth. The grafted films exhibited high stability when repetitively cycled through the Os{sup 2+/3+} couple and electron transfer rate constants of 11.4 s{sup -1} and 35.4 s{sup -1} were measured in ACN and PBS, respectively, for the Os{sup 2+/3+} couple of the film grafted from 1.

  6. Diazonium salt derivatives of osmium bipyridine complexes: Electrochemical grafting and characterisation of modified surfaces

    International Nuclear Information System (INIS)

    Garrett, David J.; Jenkins, Peter; Polson, Matthew I.J.; Leech, Donal; Baronian, Keith H.R.; Downard, Alison J.

    2011-01-01

    Osmium bipyridine complexes were directly grafted to carbon electrodes through electroreduction of the diazonium salts [Os(bpy-ph-N 2 + ) 3 ](PF 6 ) 5 (1) and [Os(bpy-ph-N 2 + ) 2 Cl 2 ](PF 6 ) 2 (2). Growth of the films was not self-limiting as is usually found for grafting from diazonium salts. It appears that electron hopping through the bipyridine ligands of the immobilised complexes enables film growth to continue at a constant rate during grafting by potential cycling. The surface concentrations of deposited films were measured electrochemically and the film thicknesses were measured by depth-profiling using the atomic force microscope. Films up to 42 nm thick were prepared with no evidence for slowing of film growth. The grafted films exhibited high stability when repetitively cycled through the Os 2+/3+ couple and electron transfer rate constants of 11.4 s -1 and 35.4 s -1 were measured in ACN and PBS, respectively, for the Os 2+/3+ couple of the film grafted from 1.

  7. Phosphate buffer and salt medium concentrations affect the inactivation of T4 phage by platinum(II) complexes

    DEFF Research Database (Denmark)

    Pedersen, Henrik B.; Josephsen, Jens; Kerszman, Gustaw

    1985-01-01

    -Tris) buffer and HEPES buffer. The phosphate abolishes the antiphage activity of the platinum complexes probably by some sort of complex formation. This together with dimerization reactions qualitatively explains the tailing off of the phage inactivation rate. High concentrations of NaNO3 as the salt medium...

  8. New glyme-cyclic imide lithium salt complexes as thermally stable electrolytes for lithium batteries

    Science.gov (United States)

    Tamura, Takashi; Hachida, Takeshi; Yoshida, Kazuki; Tachikawa, Naoki; Dokko, Kaoru; Watanabe, Masayoshi

    New glyme-Li salt complexes were prepared by mixing equimolar amounts of a novel cyclic imide lithium salt LiN(C 2F 4S 2O 4) (LiCTFSI) and a glyme (triglyme (G3) or tetraglyme (G4)). The glyme-Li salt complexes, [Li(G3)][CTFSI] and [Li(G4)][CTFSI], are solid and liquid, respectively, at room temperature. The thermal stability of [Li(G4)][CTFSI] is much higher than that of pure G4, and the vapor pressure of [Li(G4)][CTFSI] is negligible at temperatures lower than 100 °C. Although the viscosity of [Li(G4)][CTFSI] is high (132.0 mPa s at 30 °C), because of its high molar concentration (ca. 3 mol dm -3), its ionic conductivity at 30 °C is relatively high, i.e., 0.8 mS cm -1, which is slightly lower than that of a conventional organic electrolyte solution (1 mol dm -3 LiTFSI dissolved in propylene carbonate). The self-diffusion coefficients of a Li + cation, a CTFSI - anion, and a glyme molecule were measured by the pulsed gradient spin-echo NMR method (PGSE-NMR). The ionicity (dissociativity) of [Li(G4)][CTFSI] at 30 °C is ca. 0.5, as estimated from the PGSE-NMR diffusivity measurements and the ionic conductivity measurements. Results of linear sweep voltammetry revealed that [Li(G4)][CTFSI] is electrochemically stable in an electrode potential range of 0-4.5 V vs. Li/Li +. The reversible deposition-stripping behavior of lithium was observed by cyclic voltammetry. The [LiCoO 2|[Li(G4)][CTFSI]|Li metal] cell showed a stable charge-discharge cycling behavior during 50 cycles, indicating that the [Li(G4)][CTFSI] complex is applicable to a 4 V class lithium secondary battery.

  9. Scandium fluorides

    International Nuclear Information System (INIS)

    Melnikov, P.; Nalin, M.; Messaddeq, Y.

    1997-01-01

    A new modification of scandium fluoride has been synthesised. The compound is deficient in fluorine, with the composition ScF 2.76 . It belongs to the tetragonal system, lattice parameters being a=3.792 and c=6.740 A and may be obtained at low temperatures by the decomposition of the precursor NH 4 ScF 4 . The reaction is topotactic, tetragonal parameters of the precursor are a=4.021 and c=6.744 A. Structural relationships with various fluorides and ammonium aminofluorides are discussed. This synthesis route with IR-assisted decomposition should be considered as a soft-chemistry approach. (orig.)

  10. Binding orientation and interaction of bile salt in its ternary complex with pancreatic lipase-colipase system.

    Science.gov (United States)

    Haque, Neshatul; Prakash Prabhu, N

    2018-05-23

    The interfacial activity of pancreatic lipases (PL) depends on the presence of colipase and bile salt. The activity of PL is inhibited by micellar concentrations of bile salt which can be restored by the addition of colipase. Though the formation of 1:1:1 tertiary complex by lipase-colipase-bile salt micelle is well accepted, the residue-level interactions between lipase-colipase and bile salt are yet to be clearly understood. Molecular dynamic simulations of lipase-colipase complex, lipase and colipase were performed in the presence of a model bile salt, sodium taurocholate (NaTC), at its near-CMC and supra-micellar concentrations. From the interactions obtained from the molecular dynamic simulations, the ternary complex was modelled and compared with earlier reports. The analysis suggested that a micelle of NaTC consisting of nine monomers was formed at the concave groove between lipase and colipase chain and it mainly interacted with the fourth finger of colipase. This complex was mainly stabilized by van der Waals interactions. Interestingly, the C-terminal domain of lipase which holds the colipase did not show any significant role in formation or stabilization of NaTC micelle. Copyright © 2018 Elsevier Inc. All rights reserved.

  11. Spectroscopic and structural studies on some divalent metal salt of p-aminobenzoic acid (ABA(MG)) tetracyanonickelate complexes

    International Nuclear Information System (INIS)

    Atalay, Y.

    2004-01-01

    Infrared spectra of MLNi (CN) 4 [ M=Mn, Fe, Co, Ni, Zn or Cd and LDivalent metal salt of p- Aminobenzoic Acid or ABA (Mg) ] are reported. Their structure consists of polymeric layers of [M-Ni(CN) 4 ] α with the divalent metal salt of p-aminobenzoic acid [ABA(Mg)] molecules bound directly to the metal (M). These spectra were comparewith powder the Xray diffraction pattern of complexes. It is show that proposed structures for these complexes derived from Mattson 1000 FTIR spectra are consistent with the X-ray powder diffraction measurements and elemental analysis result

  12. Estimation of the development possibility of the ABC/ATW fuel cycle based on LiF-BeF2 fuel salt. Part 2

    International Nuclear Information System (INIS)

    Bychkov, A.V.; Naumov, V.S.

    1994-01-01

    The aim of the first chapter was generalization of data on solubility and equilibrium states of fission product and actinide fluorides in fluoride salt melts-solvents and fuel composition melts based on LiF-BeF 2 mixture which was proposed as fuel basis for ABC/ATW facility. The second chapter is devoted to description of processes proposed for the chemical-technological complex of the ABC/ATW facility and their physico-chemical peculiarities. The complex is responsible for the removal of fission products and actinides from irradiated fuel salt

  13. Structural Characterization of Emeraldine-Salt Polyaniline/Gold Nanoparticles Complexes

    Directory of Open Access Journals (Sweden)

    E. A. Sanches

    2011-01-01

    Full Text Available Gold nanoparticles (Au NPs stabilized with polyamidoamine dendrimers (Au-PAMAM or sodium citrate (Au-CITRATE were synthesized and complexed with polyaniline emeraldine-salt form (ES-PANI. The complexes were characterized using structural and morphological techniques, including X-Ray Diffraction (XRD, Scanning Electron Microscopy (SEM, Zeta Potential analyses, and Fourier-Transformed Infrared spectroscopy (FTIR. When the Au-CITRATE NPs are added to the polymeric solution, the formation of a precipitate is clearly observed. The precipitate exhibited a different morphology from that found for ES-PANI and Au-CITRATE NPs, suggesting the formation of ES-PANI coating over the surface of Au-CITRATE NPs. On the other hand, when the Au-PAMAM NPs are incorporated into the ES-PANI solution, none interaction was observed, probably due to the repulsive electrostatic interactions, being the organization of the ES-PANI chains unaffected by the presence of the Au-PAMAM NPs.

  14. Whey Peptide-Iron Complexes Increase the Oxidative Stability of Oil-in-Water Emulsions in Comparison to Iron Salts.

    Science.gov (United States)

    Caetano-Silva, Maria Elisa; Barros Mariutti, Lilian Regina; Bragagnolo, Neura; Bertoldo-Pacheco, Maria Teresa; Netto, Flavia Maria

    2018-02-28

    Food fortification with iron may favor lipid oxidation in both food matrices and the human body. This study aimed at evaluating the effect of peptide-iron complexation on lipid oxidation catalyzed by iron, using oil-in-water (O/W) emulsions as a model system. The extent of lipid oxidation of emulsions containing iron salts (FeSO 4 or FeCl 2 ) or iron complexes (peptide-iron complexes or ferrous bisglycinate) was evaluated during 7 days, measured as primary (peroxide value) and secondary products (TBARS and volatile compounds). Both salts catalyzed lipid oxidation, leading to peroxide values 2.6- to 4.6-fold higher than the values found for the peptide-iron complexes. The addition of the peptide-iron complexes resulted in the formation of lower amounts of secondary volatiles of lipid oxidation (up to 78-fold) than those of iron salts, possibly due to the antioxidant activity of the peptides and their capacity to keep iron apart from the lipid phase, since the iron atom is coordinated and takes part in a stable structure. The peptide-iron complexes showed potential to reduce the undesirable sensory changes in food products and to decrease the side effects related to free iron and the lipid damage of cell membranes in the organism, due to the lower reactivity of iron in the complexed form.

  15. Hydration Differences Explain the Large Variations in the Complexation Thermodynamics of Modified γ-Cyclodextrins with Bile Salts

    DEFF Research Database (Denmark)

    Køhler, Jonatan; Schönbeck, Jens Christian Sidney; Westh, Peter

    2016-01-01

    The structure and thermodynamics of inclusion complexes of seven different γ-cyclodextrins (γCDs) and three biologically relevant bile salts (BS) were investigated in the present study. Natural γCD and six modified γCDs [two methyl-γCDs, one sulfobutyl ether-γCD (SBEγCD), and three 2-hydroxypropyl...

  16. Poly(vinyl alcohol) composite films with high percent elongation prepared from amylose-fatty ammonium salt inclusion complexes

    Science.gov (United States)

    Amylose inclusion complexes prepared from cationic fatty ammonium salts and jet-cooked high amylose starch were combined with poly(vinyl alcohol) (PVOH) to form glycerol-plasticized films. Their tensile properties were compared with similar films prepared previously with analogous anionic fatty acid...

  17. Influence of complexing on physicochemical properties of polymer-salt solutions. Vliyanie kompleksoobrazovaniya na fiziko-khimicheskie svojstva polimerno-solevykh rastvorov

    Energy Technology Data Exchange (ETDEWEB)

    Ostroushko, A A; Yushkova, S M; Koridze, N V; Skobkoreva, N V; Zhuravleva, L I; Palitskaya, T A; Antropova, S V; Ostroushko, I P [Ural' skij Gosudarstvennyj Univ., Sverdlovsk (Russian Federation) AN SSSR, Moscow (Russian Federation). Inst. Obshchej i Neorganicheskoj Khimii

    1993-06-01

    Using the methods of spectrophotometry, viscosimetry, conductometry the influence of salt-polymer complexing processes on physicochemical prperties of aqueous solutions of yttrium, barium, copper nitrates and formates with polyvinyl alcohol was studied. Change of dynamic viscosity, specific electric conductivity of solutions in the process of complexing was shown. Thermal effects of salt-polymer interaction were measured. It is shown that decrease of transition temperature of polymer to plastic state in films, temperature and effective activation energy of salt decomposition is also connected with complexing. Effective values of surface tension on the boundary with air are measured. Coefficients of cation diffusion in polymer-salt solutions are estimated.

  18. A scaled experimental study of control blade insertion dynamics in Pebble-Bed Fluoride-Salt-Cooled High-Temperature Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Buster, Grant C., E-mail: grant.buster@gmail.com; Laufer, Michael R.; Peterson, Per F.

    2016-07-15

    Highlights: • A granular dynamics scaling methodology is discussed. • Control blade insertion in a representative pebble-bed core is experimentally studied. • Control blade insertion forces and pebble displacements are experimentally measured. • X-ray tomography techniques are used to observe pebble displacement distributions. - Abstract: Direct control element insertion into a pebble-bed reactor core is proposed as a viable control system in molten-salt-cooled pebble-bed reactors. Unlike helium-cooled pebble-bed reactors, this reactor type uses spherical fuel elements with near-neutral buoyancy in the molten-salt coolant, thus reducing contact forces on the fuel elements. This study uses the X-ray Pebble Bed Recirculation Experiment facility to measure the force required to insert a control element directly into a scaled pebble-bed. The required control element insertion force, and therefore the contact force on fuel elements, is measured to be well below recommended limits. Additionally, X-ray tomography is used to observe how the direct insertion of a control element physically displaces spherical fuel elements. The tomography results further support the viability of direct control element insertion into molten-salt-cooled pebble-bed reactor cores.

  19. Bottled Water and Fluoride

    Science.gov (United States)

    ... Private Wells Infant Formula Fluorosis Public Health Service Recommendation Water Operators & Engineers Water Fluoridation Additives Shortages of Fluoridation Additives Drinking Water Pipe Systems CDC-Sponsored Water Fluoridation Training Links to Other ...

  20. Other Fluoride Products

    Science.gov (United States)

    ... Private Wells Infant Formula Fluorosis Public Health Service Recommendation Water Operators & Engineers Water Fluoridation Additives Shortages of Fluoridation Additives Drinking Water Pipe Systems CDC-Sponsored Water Fluoridation Training Links to Other ...

  1. Human deoxyhaemoglobin-2,3-diphosphoglycerate complex low-salt structure at 2.5 A resolution.

    Science.gov (United States)

    Richard, V; Dodson, G G; Mauguen, Y

    1993-09-20

    The haemoglobin-2,3-diphosphoglycerate complex structure has been solved at 2.5 A resolution using crystals grown from low-salt solutions. The results show some important differences with the precedent haemoglobin-2,3-diphosphoglycerate high-salt structure solved by Arnone. First, we observe a loss of symmetry in the binding site, secondly both of the lysine residues 82 beta interact with 2,3-diphosphoglycerate at the same time, each making two contacts. This level of interaction is in agreement with the functional behaviour of natural haemoglobin mutants with mutations at the 2,3-diphosphoglycerate binding site.

  2. Fluorido complexes of technetium

    International Nuclear Information System (INIS)

    Mariappan Balasekaran, Samundeeswari

    2013-01-01

    Fluorine chemistry has received considerable interest during recent years due to its significant role in the life sciences, especially for drug development. Despite the great nuclear medicinal importance of the radioactive metal technetium in radiopharmaceuticals, its coordination chemistry with the fluorido ligand is by far less explored than that of other ligands. Up to now, only a few technetium fluorides are known. This thesis contains the synthesis, spectroscopic and structural characterization of novel technetium fluorides in the oxidation states ''+1'', ''+2'', ''+4'' and ''+6''. In the oxidation state ''+6'', the fluoridotechnetates were synthesized either from nitridotechnetic(VI) acid or from pertechnetate by using reducing agent and have been isolated as cesium or tetraethylammonium salts. The compounds were characterized spectroscopically and structurally. In the intermediate oxidation state ''+4'', hexafluoridotechnetate(IV) was known for long time and studied spectroscopically. This thesis reports novel and improved syntheses and solved the critical issues of early publications such as the color, some spectroscopic properties and the structure of this key compound. Single crystal analyses of alkali metal, ammonium and tetramethylammonium salts of hexafluoridotechnetate(IV) are presented. In aqueous alkaline solutions, the ammonium salt of hexafluoridotechnetate(IV) undergoes hydrolysis and forms an oxido-bridged dimeric complex. It is the first step hydrolysis product of hexafluoridotechnetate(IV) and was characterized by spectroscopic and crystallographic methods. Low-valent technetium fluorides with the metal in the oxidation states of ''+2'' or ''+1'' are almost unknown. A detailed description of the synthesis and characterization of pentafluoridonitrosyltechnetate(II) is presented. The complex was isolated as alkali metal salts, and spectroscopic as well as structural features of the complexes are presented. Different salts of the trans

  3. Fluoride absorption: independence from plasma fluoride levels

    International Nuclear Information System (INIS)

    Whitford, G.M.; Williams, J.L.

    1986-01-01

    The concept that there are physiologic mechanisms to homeostatically regulate plasma fluoride concentrations has been supported by results in the literature suggesting an inverse relationship between plasma fluoride levels and the absorption of the ion from the gastrointestinal tract of the rat. The validity of the relationship was questioned because of possible problems in the experimental design. The present work used four different methods to evaluate the effect of plasma fluoride levels on the absorption of the ion in rats: (i) the percentage of the daily fluoride intake that was excreted in the urine; (ii) the concentration of fluoride in femur epiphyses; (iii) the net areas under the time-plasma fluoride concentration curves after intragastric fluoride doses; and (iv) the residual amounts or fluoride in the gastrointestinal tracts after the intragastric fluoride doses. None of these methods indicated that plasma fluoride levels influence the rate or the degree or fluoride absorption. It was concluded that, unless extremely high plasma fluoride levels are involved (pharmacologic or toxic doses), the absorption of the ion is independent of plasma levels. The results provide further evidence that plasma fluoride concentrations are not homeostatically regulated

  4. Use of fluoride systems for some fission product separation from residues of fast reactor spent fuel fluorination

    International Nuclear Information System (INIS)

    Shishkov, Yu.D.; Khomyakov, V.I.

    1977-01-01

    Investigated has been a possibility of the use of fluoride systems (acid nitrozyl fluoride and molten salts) for americium extraction from residues of fluorination of irradiated fuel containing mainly fluorides of rare earth compounds, alkali and alkaline earth elements. At treatment of fission product fluorides by acid nitrozyl fluoride only cesium and uranium fluorides dissolve, while americium and rare earth fluorides are practically non-soluble in it. The solubility of cesium, strontium, barium and fluorides of some other rare earth elements in molten cryolite at the temperature of 1000 deg C, Li-NaF and LiF-CaF 2 of eutectic content at 750 and 800 deg C are respectively 15-77 %. Cerium fluoride presents an exception, its solubility in cryolite being only 0.73%. At treatment of mixture of americium and lanthanum fluorides by molten salts in the weight ratio of 1:1, approximately 50% of lanthanum and 65-70% of americium turn into melt independent of the type of melt. The maximum melt output of americium is obtained at treatment of lanthanum and americium fluoride mixture by cryolite melt at the temperature of 1000 deg C. It is shown that the presence of rare earth of fluorides, except lanthanum fluoride, effect significantly of americium distribution over phases in the process of fluoride processing by the fluoride molten salts

  5. Coupling NMR with Synchrotron radiation at high temperature for the study of molten fluorides : applied to zirconium fluorides

    International Nuclear Information System (INIS)

    Maksoud, Louis

    2013-01-01

    Molten fluorides are used in Molten Salt Reactors MSR such as the non moderated fast reactor MSFR, where the molten salt LiF-ThF 4 is the fuel and the coolant. The formation of fission products (FP) such as lanthanides, during the reactor operation, possibly modifies the physicochemical properties of the melt. It is therefore important to characterize the melt from the structural and the dynamics point of view in order to determine its properties. Because of problems related to the radioactivity of thorium, as well as requirements related to spectroscopic methods, the system studied in this thesis is the LiF-ZrF 4 -LaF 3 (zirconium and lanthanum are possible FP). The approach followed in this thesis combines measurements by NMR spectroscopy and EXAFS at 850 C with molecular dynamics simulations. In the molten salt, we have shown the existence of zirconium and lanthanum complexes with different coordination numbers, whose proportions depend on the composition. Depending on the content of ZrF 4 , [ZrF 7 ] 3- species are dominant but change slightly and are further connected between each other's via bridging fluorine. The addition of LaF 3 to the mixture stabilizes the 7 coordination number around the zirconium and tends to enrich the environment of lanthanum with fluorides. A medium-range order is established between the various complexes containing zirconium and lanthanum due to bridging fluorine. Species dynamics is slower when the amount of either ZrF 4 or LaF 3 is higher. We noted a significant effect on the structure and dynamics of species starting 10 mol% LaF 3 added to the medium. The data obtained by this novel approach concerning the chemistry of the molten salt in MSR containing FP, are fundamental to improve the separation of these products and optimize the process. (author)

  6. Solid solutions of platinum(II) and palladium(II) oxalato-complex salt as precursors of nanoalloys

    Science.gov (United States)

    Zadesenets, A. V.; Asanova, T. I.; Vikulova, E. S.; Filatov, E. Yu.; Plyusnin, P. E.; Baidina, I. A.; Asanov, I. P.; Korenev, S. V.

    2013-03-01

    A solid solution of platinum (II) and palladium (II) oxalato-complex salt, (NH4)2[Pt0.5Pd0.5(C2O4)2]·2H2O, has been synthesized and studied as a precursor for preparing bimetallic PtPd nanoparticles through its thermal decomposition. The smallest homogenous bimetallic PtPd nanoparticles were found to form in hydrogen and helium atmospheres. The annealing temperature and time have low effect on the bimetallic particles size. Comparative analysis of structural and thermal properties of the solid solution and individual Pt, Pd oxalato-complex salts was performed to investigate a mechanism of thermal decomposition of (NH4)2[Pt0.5Pd0.5(C2O4)2]·2H2O. Based on in situ X-ray photoemission spectroscopy investigation it was proposed a mechanism of formation of bimetallic PtPd nanoparticles from the solid-solution oxalato-complex salt during thermal decomposition.

  7. The corrosion behavior of CVI SiC matrix in SiC{sub f}/SiC composites under molten fluoride salt environment

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hongda [Structural Ceramics and Composites Engineering Research Center, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); School of Graduate, University of Chinese Academy of Sciences, Beijing 100049 (China); Feng, Qian [Analysis and Testing Center, Donghua University, Shanghai 201600 (China); Wang, Zhen, E-mail: jeff@mail.sic.ac.cn [Structural Ceramics and Composites Engineering Research Center, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Zhou, Haijun; Kan, Yanmei; Hu, Jianbao [Structural Ceramics and Composites Engineering Research Center, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Dong, Shaoming, E-mail: smdong@mail.sic.ac.cn [Structural Ceramics and Composites Engineering Research Center, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China)

    2017-04-15

    High temperature corrosion behavior and microstructural evolution of designed chemical-vapor-infiltrated SiC matrix in SiC fiber reinforced SiC ceramic matrix composites in 46.5LiF-11.5NaF-42.0KF (mol. %) eutectic salt at 800 °C for various corrosion time was studied. Worse damage was observed as extending the exposure time, with the mass loss ratio increasing from 0.716 wt. % for 50 h to 5.914 wt. % for 500 h. The mass loss rate showed a trend of first decrease and then increase with the extended corrosion exposure. Compared with the near-stoichiometric SiC matrix layers, the O-contained boundaries between deposited matrix layers and the designed Si-rich SiC matrix layers were much less corrosion resistant and preferentially corroded. Liner relationship between the mass loss ratio and the corrosion time obtained from 50 h to 300 h indicated that the corrosion action was reaction-control process. Further corrosion would lead to matrix layer exfoliation and higher mass loss ratio.

  8. Fluoride removal from water by nano filtration

    International Nuclear Information System (INIS)

    Bejaoui, Imen; Mnif, Amine; Hamrouni, Bechir

    2009-01-01

    As any oligo element, fluoride is necessary and beneficial for human health to low concentrations, but an excess amount of fluoride ions in drinking water has been known to cause undesirable effects, especially tooth and bones fluoro sis. The maximum acceptable concentration of fluoride in drinking water was fixed by the World Health Organization according to the climate in the range of 1 mg.L -1 to 1,2 mg.L -1 . Many methods have been used to remove fluoride from water such as precipitation, adsorption, electrocoagulation and membrane processes. Technologies using membrane processes are being used in many applications, particularly for brackish water desalination. Nano filtration seems to be the best process for a good selective defluorination of fluorinated waters. The main objective of this work was to investigate the retention of fluoride anions by nano filtration. The first part of this study deals with the characterisation of the NF HL2514TF membrane. The influence of various experimental parameters such as initial fluoride content, feed pressure, permeate flux, ionic strength, type of cation associated to fluoride and pH were studied in the second part. Results show that the retention order for the salts tested was TR(Na 2 SO 4 ) > TR(CaCl 2 ) > TR(NaCl), showing a retention sequence inversely proportional to the salt diffusion coefficients in water. It was also shown that charge effects could not be neglected, and a titration experiments confirmed that the NF membrane carry a surplus of negatively charged groups. Fluoride retention exceeds 60 pour cent, and increases with increasing concentration, where the rejection mechanism is related to the dielectric effects. Speigler-Kedem model was applied to experimental results in the aim to determine phenomenological parametersσand P s respectively, the reflexion coefficient of the membrane and the solute permeability of ions. The convective and diffusive parts of the mass transfer were quantified with

  9. Molybdenum carbide coating electrodeposited from molten fluoride bath

    International Nuclear Information System (INIS)

    Topor, D.C.; Selman, J.R.

    1987-01-01

    Molybdenum carbide has been recently considered as a candidate material for the protection of common steel-based substrates in high-temperature high-sulfur activity applications. Methods to produce coatings of materials such as Mo/sub 2/C are scarce and only the electrodeposition from molten salts can yield dense, pore-free layers on various metallic profiles. Recently Stern reported the deposition of a Mo/sub 2/C coating on nickel substrate form, FLINAK + K/sub 2/MoCl/sub 6/ + Na/sub 2/CO/sub 3/ mixture at 850 0 C. Electrodeposition of Mo/sub 2/C on a cathode surface proceeds according to a rather complicated mechanism which may involve simultaneous reduction of carbonate to C, of molybdate to Mo and a subsequent chemical reaction between both species. The deposit grows further as a coherent coating. Reduction of CO/sub 2/ or carbonate to carbon in a fused salt medium could follow different paths but Li/sup +/ ions or other highly polarizing ions must be present. A similar situation in which a polyatomic anion discharges at the cathode is encountered when molybdates are used as source of molybdenum. In fluoride melts the chemistry of Mo(VI) species is considered to be much simpler due to the hard fluoride ions. These ions form strong complexes with molybdenum and the resulting solution is more stable

  10. Crystal structure of a dinuclear CoII complex with bridging fluoride ligands: di-μ-fluorido-bis{tris[(6-methylpyridin-2-ylmethyl]amine}dicobalt(II bis(tetrafluoridoborate

    Directory of Open Access Journals (Sweden)

    Masataka Inomata

    2014-11-01

    Full Text Available Reaction of Co(BF42·6H2O with tris[(6-methylpyridin-2-ylmethyl]amiine in methanol results in a fluoride abstraction from BF4−, yielding the unexpected title compound, [Co2F2(C21H24N42](BF42. The complex cation consists of two inversion-related [Co(C21H24N4]2+ moieties bridged by a pair of fluoride ligands. The CoII cation is six-coordinated in a distorted octahedral geometry and forms a +II high-spin state. In the crystal, the complex cation and the BF4− anion are connected by C—H...F hydrogen bonds, forming a three-dimensional network. An intramolecular C—H...F hydrogen bond is also observed.

  11. Thermodynamic study on salt effects on complex formation of α-, β- and γ-cyclodextrins with p-aminobenzoic acid

    International Nuclear Information System (INIS)

    Chibunova, E.S.; Kumeev, R.S.; Terekhova, I.V.

    2015-01-01

    Highlights: • Thermodynamic study on salt effects in CD/pABA complex formation was performed. • Effects of KCl, KH 2 PO 4 and K 2 SO 4 are insignificant and nonspecific. • Specific influence of KBr is caused by the ability of Br − to penetrate into CD cavity. • Coexistence of two complexation equilibria is accompanied by solvent reorganization. - Abstract: The aim of this work was to gain a deeper understanding of salt effects in the inclusion complex formation of cyclodextrins. For this purpose, thermodynamic study of complex formation of α-, β- and γ-cyclodextrins with p-aminobenzoic acid was carried out in water and solutions of KCl, KBr, KH 2 PO 4 and K 2 SO 4 (0.2 mol/kg). Stability constants were calculated from the binding isotherms obtained on the basis of 1 H NMR measurements. Enthalpy and entropy of complex formation were estimated from the van’t Hoff plots. It was found that effects of KCl, KH 2 PO 4 and K 2 SO 4 are insignificant, while the influence of KBr on complex formation of cyclodextrins with p-aminobenzoic acid is more pronounced and results in a decrease of the stability constants. Specific action of Br − is caused by the ability of these anions to penetrate into macrocyclic cavity. Coexistence of two complexation equilibria in KBr solution is accompanied by significant solvent reorganization originated from more intensive dehydration of the interacting species. This results in an increase of the enthalpy and entropy of complex formation. Manifestation of Br − effect was found to be the same in the binding of p-aminobenzoic acid with α-, β- and γ-cyclodextrins.

  12. Correction: A binary catalyst system of a cationic Ru-CNC pincer complex with an alkali metal salt for selective hydroboration of carbon dioxide.

    Science.gov (United States)

    Ng, Chee Koon; Wu, Jie; Hor, T S Andy; Luo, He-Kuan

    2016-12-22

    Correction for 'A binary catalyst system of a cationic Ru-CNC pincer complex with an alkali metal salt for selective hydroboration of carbon dioxide' by Chee Koon Ng et al., Chem. Commun., 2016, 52, 11842-11845.

  13. Fluoride varnish or fluoride mouth rinse?

    DEFF Research Database (Denmark)

    Keller, M K; Klausen, BJ; Twetman, S

    2016-01-01

    OBJECTIVE: In many Danish communities, school-based fluoride programs are offered to children with high caries risk in adjunct to tooth brushing. The purpose of this field trial was to compare the caries-preventive effectiveness of two different fluoride programs in 6-12 year olds. BASIC RESEARCH...... different schools were enrolled after informed consent and their class unit was randomly allocated to one of two fluoride programs. INTERVENTIONS: One group received a semi-annual fluoride varnish applications (FV) and the other group continued with an existing program with fluoride mouth rinses once per...... in caries development over two years among children participating in a school-based fluoride varnish or mouth rinse program....

  14. In the presence of fluoride, free Sc³⁺ is not a good predictor of Sc bioaccumulation by two unicellular algae: possible role of fluoro-complexes.

    Science.gov (United States)

    Crémazy, Anne; Campbell, Peter G C; Fortin, Claude

    2014-08-19

    We investigated the effect of fluoride complexation on scandium accumulation by two unicellular algae, Chlamydomonas reinhardtii and Pseudokirchneriella subcapitata. This trivalent metal was selected for its chemical similarities with aluminum and for its convenient radioisotope (Sc-46), which can be used as a tracer in short-term bioaccumulation studies. Scandium surface-bound concentrations (Sc(ads)) and uptake fluxes (J(int)) were estimated in the two algae over short-term (organisms.

  15. Inhibition of cellular oxidation by fluoride

    Energy Technology Data Exchange (ETDEWEB)

    Borei, H

    1945-01-01

    An attempt has been made to investigate the inhibition by fluoride of the oxidative processes which occur in the cell by way of the cytochrome oxidase-cytochrome system. Some chemical and physical properties of the fluoride ion are discussed, together with certain quantitative methods for the determination of fluoride. An exhaustive review of the literature concerning the effect of fluoride on enzymic processes has been compiled. The experiments have shown that the point of the attack by fluoride is to be found among the cytochromes. The inhibitory mechanism appears to be such that the haemoprotein is prevented from taking part in the preceding and succeeding links in the reaction chain. The blocking action leaves the prosthetic group of the haemoprotein completely unchanged. The experimental results indicate the formation of a fluorophosphoprotein complex, analogous to that found in the case of enolase. Magnesium may possibly play a part in this process.

  16. Calcium fluoride

    International Nuclear Information System (INIS)

    King, C.W.; Nestor, O.H.

    1989-01-01

    A new process for producing large, single, oriented crystals of calcium fluoride (CaF 2 ) has been developed which overcomes the limitations of current growing methods. This process has been reduced to practice and has yielded oriented crystals 17.5 x 17.5 x 5 cm 3 . Currently nearing completion is a system for producing 35 x 35 x 7.5 cm 3 single crystals. A scale up to one-meter-square is considered feasible. This crystal growing process makes possible the fabrication of very large CaF 2 windows. Suitability for very high power lasers, however, requires attention to properties beyond mere size. A process to generate higher purity growth stock (starting material) was also developed. The additional purification of the growth stock contributes to lower bulk absorption, the absence of color centers and increased radiation hardness. Also identified were several specific impurities which correlate with radiation hardness. A correlation was found between color centers induced by laser radiation and ionizing radiation. Other CaF 2 crystal properties such as tensile strength, absorption and laser damage thresholds were studied and are discussed

  17. Investigation of complexing in solutions of salt mixture In(NO3)3-NaVO3

    International Nuclear Information System (INIS)

    Nakhodnova, A.N.; Listratenko, I.V.

    1987-01-01

    Spectrophotometry, conductometry and pH-metry are used to investigate properties and composition of the solid phases of isomolar series of In(NO 3 ) 3 -NaVO 3 salt mixture solutions and series of solutions having constant concentration of one of the components and varied of the other. Results of investigation are presented. It is stated that in the investigated solution series in weakly acid media HPA with the ratios [In 3+ ]:[V 5+ ] being equal to 11:1, 6:1, and 1:9, are formed. Composition of the complexes is mainly defined by the ratio of the components in In(NO 3 ) 3 and NaVO 3 salt mixture solutions and the medium acidity. Compounds of Na 2 OxIn 2 O 3 x2.5V 2 O 5 x8.5H 2 O and Cs 2 OxIn 2 O 3 x6V 2 O 5 x6.5H 2 O empirical formulae are separated. Results of IR spectroscopy, derivatography and X-ray phase analysis of the corresponding salts are presented

  18. Investigation of complexing in solutions of salt mixture In(NO/sub 3/)/sub 3/-NaVO/sub 3/

    Energy Technology Data Exchange (ETDEWEB)

    Nakhodnova, A N; Listratenko, I V

    1987-05-01

    Spectrophotometry, conductometry and pH-metry are used to investigate properties and composition of the solid phases of isomolar series of In(NO/sub 3/)/sub 3/-NaVO/sub 3/ salt mixture solutions and series of solutions having constant concentration of one of the components and varied of the other. Results of investigation are presented. It is stated that in the investigated solution series in weakly acid media HPA with the ratios (In/sup 3+/):(V/sup 5+/) being equal to 11:1, 6:1, and 1:9, are formed. Composition of the complexes is mainly defined by the ratio of the components in In(NO/sub 3/)/sub 3/ and NaVO/sub 3/ salt mixture solutions and the medium acidity. Compounds of Na/sub 2/OxIn/sub 2/O/sub 3/x2.5V/sub 2/O/sub 5/x8.5H/sub 2/O and Cs/sub 2/OxIn/sub 2/O/sub 3/x6V/sub 2/O/sub 5/x6.5H/sub 2/O empirical formulae are separated. Results of IR spectroscopy, derivatography and X-ray phase analysis of the corresponding salts are presented.

  19. Conformational coupling between receptor and kinase binding sites through a conserved salt bridge in a signaling complex scaffold protein.

    Directory of Open Access Journals (Sweden)

    Davi R Ortega

    Full Text Available Bacterial chemotaxis is one of the best studied signal transduction pathways. CheW is a scaffold protein that mediates the association of the chemoreceptors and the CheA kinase in a ternary signaling complex. The effects of replacing conserved Arg62 of CheW with other residues suggested that the scaffold protein plays a more complex role than simply binding its partner proteins. Although R62A CheW had essentially the same affinity for chemoreceptors and CheA, cells expressing the mutant protein are impaired in chemotaxis. Using a combination of molecular dynamics simulations (MD, NMR spectroscopy, and circular dichroism (CD, we addressed the role of Arg62. Here we show that Arg62 forms a salt bridge with another highly conserved residue, Glu38. Although this interaction is unimportant for overall protein stability, it is essential to maintain the correct alignment of the chemoreceptor and kinase binding sites of CheW. Computational and experimental data suggest that the role of the salt bridge in maintaining the alignment of the two partner binding sites is fundamental to the function of the signaling complex but not to its assembly. We conclude that a key feature of CheW is to maintain the specific geometry between the two interaction sites required for its function as a scaffold.

  20. Story of Fluoridation

    Science.gov (United States)

    ... Home Health Info Health Topics Fluoride Share The Story of Fluoridation It started as an observation, that ... this time using photospectrographic analysis, a more sophisticated technology than that used by McKay. Churchill asked an ...

  1. Fluoride in diet

    Science.gov (United States)

    Diet - fluoride ... bones and teeth. Too much fluoride in the diet is very rare. Rarely, infants who get too ... of essential vitamins is to eat a balanced diet that contains a variety of foods from the ...

  2. Weak bases and formation of a less soluble lauryl sulfate salt/complex in sodium lauryl sulfate (SLS) containing media.

    Science.gov (United States)

    Bhattachar, Shobha N; Risley, Donald S; Werawatganone, Pornpen; Aburub, Aktham

    2011-06-30

    This work reports on the solubility of two weakly basic model compounds in media containing sodium lauryl sulfate (SLS). Results clearly show that the presence of SLS in the media (e.g. simulated gastric fluid or dissolution media) can result in an underestimation of solubility of some weak bases. We systematically study this phenomenon and provide evidence (chromatography and pXRD) for the first time that the decrease in solubility is likely due to formation of a less soluble salt/complex between the protonated form of the weak base and lauryl sulfate anion. Copyright © 2011 Elsevier B.V. All rights reserved.

  3. Fluoride metabolism in plants

    Energy Technology Data Exchange (ETDEWEB)

    Peters, R; Shorthouse, M

    1964-04-04

    Grass seedlings exposed to inorganic fluoride solutions do not take up appreciable amounts of fluoride until concentrations of more than 1.0 mM (19 p.p.m.) are used. No formation of organic fluoride has been found, even with exposure to 15.75 mM fluoride, indicating that there is no formation of fluoroacetate or similar compounds. 8 references, 2 tables.

  4. Indirect Voltammetric Sensing Platforms For Fluoride Detection on Boron-Doped Diamond Electrode Mediated via [FeF6]3− and [CeF6]2− Complexes Formation

    International Nuclear Information System (INIS)

    Culková, Eva; Tomčík, Peter; Švorc, Ľubomír; Cinková, Kristína; Chomisteková, Zuzana; Durdiak, Jaroslav; Rievaj, Miroslav; Bustin, Dušan

    2014-01-01

    Very simple and sensitive electroanalytical technique based on synergistic combination of reaction electrochemistry (specificity) and bare boron-doped diamond electrode (sensitivity) for the detection of fluorides in drinking water was developed as variant based on dynamic electrochemistry to ISE analysis. It is based on the formation of electroinactive fluoride complexes with Fe(III) and Ce(IV) ions decreasing such diffusion current of free metal on boron-doped diamond electrode. Due to low background signal of boron-doped diamond electrode reasonably low detection limits of the order of 10 −6 mol L −1 for linear sweep voltammetric method using formation of [FeF 6 ] 3− and 10 −7 mol L −1 in a square-wave variant of this technique have been achieved. This is approximately 1–2 orders lower than in the case of platinum comb-shaped interdigitated microelectrode array. Linear sweep voltammetric method based on [CeF 6 ] 2− complex formation has lower sensitivity and may be suitable for samples with higher content of fluoride and not to analysis of drinking water

  5. Concept of the demonstration molten salt unit for the transuranium elements transmutation

    International Nuclear Information System (INIS)

    Alekseev, P.; Dudnikov, A.; Prusakov, V.; Subbotin, S.; Zakirov, R.; Lelek, V.; Peka, I.

    1999-01-01

    In this report it is considered fluorine reprocessing of spent fuel and fluoride molten salt reactor in critical and subcritical modes for plutonium and minor actinides burning. International collaboration for creation of such system is proposed. It is without any doubt that additional neutron source in the core will have positive influence on the transmutation process in the reactor. On the other side there is a lot of problems to realize it technically and to ensure stable work of the whole complex. (Authors)

  6. Fluoride glass fiber optics

    CERN Document Server

    Aggarwal, Ishwar D

    1991-01-01

    Fluoride Glass Fiber Optics reviews the fundamental aspects of fluoride glasses. This book is divided into nine chapters. Chapter 1 discusses the wide range of fluoride glasses with an emphasis on fluorozirconate-based compositions. The structure of simple fluoride systems, such as BaF2 binary glass is elaborated in Chapter 2. The third chapter covers the intrinsic transparency of fluoride glasses from the UV to the IR, with particular emphasis on the multiphonon edge and electronic edge. The next three chapters are devoted to ultra-low loss optical fibers, reviewing methods for purifying and

  7. Salt-induced phase separation for the determination of metals as their diethyldithiocarbamate complexes by high-performance liquid chromatography

    International Nuclear Information System (INIS)

    Mueller, B.J.; Lovett, R.J.

    1987-01-01

    Reversed-phase high-performance liquid chromatography with ultraviolet detection can be used to determine trace levels of Pt(II), Pd(II), Rh(III), Co(III), Ru(III), and Ir in aqueous solution following complexation with diethyldithiocarbamate. The metal complexes are extracted into acetonitrile from aqueous solution by the addition of a saturated salt solution. Quantitative metal recovery from aqueous solution is achievable for most metals for a wide solution pH range. Detection limits for the metals are <3 ng of metal/mL of original aqueous sample. Analyses of real samples are highly reproducible and sensitive. Ir an interfere in the determination of Pt(II) and Rh(III). A general protocol for chromatographic separation and determination of Pt(II), Pd(II), Rh(III), Ru(III), and Ir in aqueous solution is presented

  8. Structural and Redox Properties of Vanadium Complexes in Molten Salts of Interest for the Catalytic Oxidation of Sulfur Dioxide

    DEFF Research Database (Denmark)

    Boghosian, S.; Chrissanthopoulos, A.; Fehrmann, Rasmus

    2000-01-01

    Electronic absorption (UV/VIS) spectra have been obtained at 450 degrees C from V2O5-K2S2O7 molten mixtures in SO2 ( P-SO2 = 0 - 1.2 atm) gas atmospheres. The data are in agreement with the V-V reversible arrow V-IV equilibrium: (VO)(2)O(SO4)(4)(4-)(l) + SO2(g) - 2VO(SO4)(2)(2-)(l) + SO3(g). Sulfur...... and vibrational properties of the vanadium complexes formed in the molten salt-gas system V2O5-M2S2O7-M2SO4/SO2-O-2 (M = K or Cs). The spectral features and the exploitation of the relative Raman intensities indicate that the (VO)(2)O(SO4)(4)(+) dimeric complex unit which possesses a V-O-V bridge is formed...

  9. Study of nonequilibrium steady state of Fe(II) complex salt by means of synchrotron-radiation x-ray

    CERN Document Server

    Moritomo, Y

    2003-01-01

    In this article, we introduce our recent investigation at SPring-8/BL02B2 on the nonequilibrium steady state of photoexcited spin-crossover salts, which consists of Fe sup 2 sup + complexes and counter cations. The Fe sup 2 sup + complex takes two states; one is the low-spin state (S=0) and the other is the high-spin state (S=2). The photoexcitation can convert the low-spin site into the high-spin state, and hence, a finite the high-spin site is excited balancing with the thermal relaxation process. When the excitation power exceeds a critical value, we observe a dynamical phase transition into the high-spin condensed state.

  10. Investigation of regularities of uranyl salts complexing with neutral bases in nonaqueous media

    International Nuclear Information System (INIS)

    Kobets, L.V.; Buchikhin, E.P.

    1986-01-01

    Anhydrous uranyl chloride complexing with neutral oxygen-containing organic bases (sulfoxides, organic phosphates, phosphinates, phosphinoxides, N-oxides) in the acetone medium depending on the donor capacity of neutral molecules is discussed. The constants of 1:1 complexes dissociation are shown to detect no correlation with the donor capacity of neutral bases. At the same time stability constants of complexes increase as the donor capacity of ligands grows. But the dependence is of a complex character and is determined by the nature of neutral molecules. Estimation of uranyl chloride and 0-donor contributions into the values of stability constants and complex formation heats is given

  11. Modeling of Flow, Transport and Controlled Sedimentation Phenomena during Mixing of Salt Solutions in Complex Porous Formations

    Science.gov (United States)

    Skouras, Eugene D.; Jaho, Sofia; Pavlakou, Efstathia I.; Sygouni, Varvara; Petsi, Anastasia; Paraskeva, Christakis A.

    2015-04-01

    The deposition of salts in porous media is a major engineering phenomenon encountered in a plethora of industrial and environmental applications where in some cases is desirable and in other not (oil production, geothermal systems, soil stabilization etc). Systematic approach of these problems requires knowledge of the key mechanisms of precipitating salts within the porous structures, in order to develop new methods to control the process. In this work, the development and the solution of spatiotemporally variable mass balances during salt solution mixing along specific pores were performed. Both analytical models and finite differences CFD models were applied for the study of flow and transport with simultaneous homogeneous and heterogeneous nucleation (by crystal growth on the surface of the pores) in simple geometries, while unstructured finite elements and meshless methods were developed and implemented for spatial discretization, reconstruction, and solution of transport equations and homogeneous / heterogeneous reactions in more complex geometries. At initial stages of this work, critical problem parameters were identified, such as the characteristics of the porosity, the number of dissolved components, etc. The parameters were then used for solving problems which correspond to available experimental data. For each combination of ions and materials, specific data and process characteristics were included: (a) crystal kinetics (nucleation, growth rates or reaction surface rates of crystals, critical suspension concentrations), (b) physico-chemical properties (bulk density, dimensions of generated crystals, ion diffusion coefficients in the solution), (c) operating parameters (macroscopic velocity, flow, or pressure gradient of the solution, ion concentration) (d) microfluidic data (geometry, flow area), (e) porosity data in Darcy description (initial porosity, specific surface area, tortuosity). During the modeling of flow and transport in three

  12. Preparation of uranium ingots from double fluorides

    International Nuclear Information System (INIS)

    Le Boulbin, E.

    1967-05-01

    A simple method has been developed for the preparation of uranium double fluorides and has given a new impetus to the study of the reduction of these compounds with a view to obtaining very pure uranium ingots. This reduction can be carried out using calcium or magnesium as the reducing agent, this latter metal being very interesting from the practical point of view. A comparative study of the heat balances of the reduction processes for the double fluorides and for uranium tetrafluoride has shown that reduction of the double fluorides is possible. The exact experimental conditions for these reductions have been determined. Our study has shown in particular that the reduction of the double salt UF 4 , CaF 2 by magnesium leads to the production of small (20 to 500 g) samples of high-purity uranium with a yield of 99 per cent. (author) [fr

  13. Cladding Alloys for Fluoride Salt Compatibility

    Energy Technology Data Exchange (ETDEWEB)

    Muralidharan, Govindarajan [ORNL; Wilson, Dane F [ORNL; Walker, Larry R [ORNL; Santella, Michael L [ORNL; Holcomb, David Eugene [ORNL

    2011-06-01

    This report provides an overview of several candidate technologies for cladding nickel-based corrosion protection layers onto high-temperature structural alloys. The report also provides a brief overview of the welding and weld performance issues associated with joining nickel-clad nickel-based alloys. From the available techniques, two cladding technologies were selected for initial evaluation. The first technique is a line-of-sight method that would be useful for cladding large structures such as vessel interiors or large piping. The line-of-sight method is a laser-based surface cladding technique in which a high-purity nickel powder mixed into a polymer binder is first sprayed onto the surface, baked, and then rapidly melted using a high-power laser. The second technique is a vapor phase technique based on the nickel-carbonyl process that is suitable for cladding inaccessible surfaces such as the interior surfaces of heat exchangers. An initial evaluation for performed on the quality of nickel claddings processed using the two selected cladding techniques.

  14. Mass spectra of alkaline earth salts with a FAB source. Complexation with crown ethers

    International Nuclear Information System (INIS)

    Ulrich, J.

    1987-01-01

    With a liquid desorption FAB source it is possible to obtain alkaline earth metal ions complexed by a crown ether. Conditions for formation of these complexes ions are examined for selection of the complexing agent in function of cation size. Behaviour of alkaline and alkaline earth compounds are compared allowing the differentiation of ion extraction phenomena by liquid desorption ion source and solvent extraction [fr

  15. Colchiceine Complexes with Lithium, Sodium and Potassium Salts − Spectroscopic Studies

    Directory of Open Access Journals (Sweden)

    Joanna Kurek

    2016-09-01

    Full Text Available Colchiceine complexes with Li+, Na+ and K+ cations have been synthesized and studied by 1H and 13C NMR, FT-IR, FAB MS and UV-Vis. It has been shown that colchiceine forms stable complexes especially with lithium cation and the most stable structures of the complexes are those in which the acetamide groups are involved in the coordination process. The structures of the colchiceine complexes with Li+, Na+ and K+ cations are discussed in details. This work is licensed under a Creative Commons Attribution 4.0 International License.

  16. Chemical mechanism of the fluoride-inhibition of fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Warburg, O; Christian, W

    1941-08-01

    Among the fluoride-sensitive fermentation elements, enolase is the most sensitive. An investigation was made, quantitatively, of fluoride inhibition for chemically pure magnesium-enolase using an optical enolase test. Data show that the effective compound for fluoride inhibition is a complex magnesium-fluoro-phosphate and that the magnesium-fluoro-phosphate inhibits fermentation by combining proportionally to its concentration with the ferment-protein in a dissociating manner.

  17. Spectrophotometric determination of fluoride with alizarin complexone

    Energy Technology Data Exchange (ETDEWEB)

    Marczenko, Z; Lenarczyk, L [Politechnika Warszawska (Poland)

    1976-01-01

    The modification of direct spectrophotometric method of fluoride determination by alizarin complexone has been developed. It was shown that the lanthanum alizarin complexone chelate is more convenient than that of cerium (3). The influence of acetone, dioxane and dimethyl sulphoxide in water solution on the increase of sensitivity of the method and the rate of colour reaction has been determined. The optimal pH ranges for the reaction with lanthanum and cerium (3) have been estimated. Some amines having a large molecule are useful for extraction of blue fluoride complex with isobutanol. Dioctylamine was applied in a new extraction spectrophotometric procedure of fluoride determination. Conditions in reagent have been established. Both variants of the method have been applied to the fluoride determination in several chemicals. The obtained results show a good precision and accuracy.

  18. Dissecting the salt dependence of the Tus-Ter protein-DNA complexes by high-throughput differential scanning fluorimetry of a GFP-tagged Tus.

    Science.gov (United States)

    Moreau, Morgane J J; Schaeffer, Patrick M

    2013-12-01

    The analysis of the salt dependence of protein-DNA complexes provides useful information about the non-specific electrostatic and sequence-specific parameters driving complex formation and stability. The differential scanning fluorimetry of GFP-tagged protein (DSF-GTP) assay has been geared with an automatic Tm peak recognition system and was applied for the high-throughput (HT) determination of salt-induced effects on the GFP-tagged DNA replication protein Tus in complex with various Ter and Ter-lock sequences. The system was designed to generate two-dimensional heat map profiles of Tus-GFP protein stability allowing for a comparative study of the effect of eight increasing salt concentrations on ten different Ter DNA species at once. The data obtained with the new HT DSF-GTP allowed precise dissection of the non-specific electrostatic and sequence-specific parameters driving Tus-Ter and Tus-Ter-lock complex formation and stability. The major factor increasing the thermal resistance of Tus-Ter-lock complexes in high-salt is the formation of the TT-lock, e.g. a 10-fold higher Kspe was obtained for Tus-GFP:Ter-lockB than for Tus-GFP:TerB. It is anticipated that the system can be easily adapted for the study of other protein-DNA complexes.

  19. Private Well Water and Fluoride

    Science.gov (United States)

    ... Private Wells Infant Formula Fluorosis Public Health Service Recommendation Water Operators & Engineers Water Fluoridation Additives Shortages of Fluoridation Additives Drinking Water Pipe Systems CDC-Sponsored Water Fluoridation Training Links to Other ...

  20. Hydration Differences Explain the Large Variations in the Complexation Thermodynamics of Modified γ-Cyclodextrins with Bile Salts.

    Science.gov (United States)

    Køhler, Jonatan; Schönbeck, Christian; Westh, Peter; Holm, René

    2016-01-28

    The structure and thermodynamics of inclusion complexes of seven different γ-cyclodextrins (γCDs) and three biologically relevant bile salts (BS) were investigated in the present study. Natural γCD and six modified γCDs [two methyl-γCDs, one sulfobutyl ether-γCD (SBEγCD), and three 2-hydroxypropyl-γCDs (HPγCD)] and their complexes with BS were investigated by isothermal titration calorimetry, NMR, and molecular dynamics simulations. With the exception of the fully methylated γCD, which did not bind the BSs investigated, all of the γCDs formed 1:1 complexes with the BS, and the structures were similar to those with natural γCD; i.e., the modifications of the γCD had limited structural impact on the formation of complexes. Isothermal titration calorimetry was carried out over in the temperature interval 5-55 °C to enable the calculation of the stability constant (K) and the thermodynamic parameters enthalpy (ΔH°), entropy (ΔS°), and heat capacity (ΔCp°). The stability constants decreased with an increased degree of substitution (DS), with methyl substituents having a lower effect on the stability constant than the sulfobutyl ether and hydroxypropyl substituents on the stability constants. Enthalpy-entropy compensation was observed, since both enthalpy and entropy increased with the degree of substitution, which may reflect dehydration of the hydrophobic surface on both CD and BS. Calculations based on ΔCp° data suggested that each of the substituents dehydrated 10-20 (hydroxypropyl), 22-33 (sulfobutyl ether), and 10-15 Å(2) (methyl) of the BS surface area, in reasonable agreement with estimates from the molecular dynamics simulations. Combined with earlier investigations on modified βCDs, these results indicate general trends of the substituents on the thermodynamics of complex formation.

  1. Studies on cluster, salt and molecular complex of zinc-quinolinate

    Indian Academy of Sciences (India)

    Reactions of zinc halides with 8-hydroxyquinoline (hydroxQ) in equimolar ratio were carried out in different solvents. ... determination of surface area. We prepared a ..... resulted in the formation of de-solvated complex, which on standing at ...

  2. Preparation and properties of amylose complexes prepared from hexadecylamine and its hydrochloride salt

    Science.gov (United States)

    Amylose inclusion complexes were prepared from jet-cooked aqueous mixtures of high amylose corn starch and 1-hexadecylamine (HDA). Slow-cooling produced torus/disc-shaped spherulites, whereas aggregates of smaller spherulites were obtained by rapid-cooling in ice. The morphologies and 6(1)V x-ray ...

  3. Process development for treatment of fluoride containing wastes

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Mahesh; Kanvinde, V Y [Chemical Engineering Division, Bhabha Atomic Research Centre, Mumbai (India)

    1994-06-01

    Many chemical and metallurgical industries generate liquid wastes containing high values of fluorides in association of nitrates and other metals. Due to harmful effects of fluorides these type of wastes can not be disposed off in the environment without proper treatment. Bench-scale laboratory experiments were conducted to develop a process scheme to fix the fluorides as non-leachable solid waste and fluoride free treated liquid waste for their disposal. To optimize the important parameters, simulated synthetic and actual wastes were used. For this study, three waste streams were collected from Nuclear Fuel Complex, Hyderabad. (author). 6 tabs., 1 fig.

  4. Internal deformation in layered Zechstein-III K-Mg salts. Structures formed by complex deformation and high contrasts in viscosity observed in drill cores.

    Science.gov (United States)

    Raith, Alexander; Urai, Janos L.

    2016-04-01

    During the evaporation of a massive salt body, alternations of interrupted and full evaporation sequences can form a complex layering of different lithologies. Viscosity contrasts of up to five orders of magnitude between these different lithologies are possible in this environment. During the late stage of an evaporation cycle potassium and magnesium (K-Mg) salts are precipitated. These K-Mg salts are of economic interest but also a known drilling hazard due to their very low viscosity. How up to 200m thick layers of these evaporites affect salt deformation at different scales is not well known. A better understanding of salt tectonics with extreme mechanical stratification is needed for better exploration and production of potassium-magnesium salts and to predict the internal structure of potential nuclear waste repositories in salt. To gain a better understanding of the internal deformation of these layers we analyzed K-Mg salt rich drill cores out of the Zechstein III-1b subunit from the Veendam Pillow 10 km southeast of Groningen, near the city Veendam in the NE Netherlands. The study area has a complex geological history with multiple tectonic phases of extension and compression forming internal deformation in the pillow but also conserving most of the original layering. Beside halite the most common minerals in the ZIII-1b are carnallite, kieserite, anhydrite and bischofite alternating in thin layers of simple composition. Seismic interpretation revealed that the internal structure of the Veendam Pillow shows areas, in which the K-Mg salt rich ZIII 1b layer is much thicker than elsewhere, as a result of salt deformation. The internal structure of the ZIII-1b on the other hand, remains unknown. The core analysis shows a strong strain concentration in the weaker Bischofite (MgCl2*6H20) and Carnallite (KMgCl3*6H20) rich layers producing tectonic breccias and highly strained layers completely overprinting the original layering. Layers formed by alternating beds

  5. Sulfochlorphenol S as reagent for direct photometric determination of fluorides

    International Nuclear Information System (INIS)

    Dzhashi, D.O.; Dedkova, V.P.; Savvin, S.B.

    1978-01-01

    The system of zirconium-sulfochlorphenol S-fluoride was studied by the spectrophotometry method. The effect of pH, temperature and time on the formation of zirconium complexes with sulfochlorphenol S was investigated. A comparison of the above method of determining fluorides with other methods (using alizarinecomplexonate, quinalizarincomplexonate, cerium chelates, lanthanum, arsenazo 3) is presented. The sensitivity of determining fluorides with arsenazo 3 is lower than that with sulfochlorphenol S. The molar absorption coefficient is 3x10 4 , the reaction of determining fluorides with the aid of sulfochlorphenol S is highly selective. The method was used to determine fluorides in the supply water, zirconium solutions and electrolyzer cell. The range of concentration determination for fluorides is 0-3 μg/25 ml

  6. Fluorido complexes of technetium

    Energy Technology Data Exchange (ETDEWEB)

    Mariappan Balasekaran, Samundeeswari

    2013-07-04

    Fluorine chemistry has received considerable interest during recent years due to its significant role in the life sciences, especially for drug development. Despite the great nuclear medicinal importance of the radioactive metal technetium in radiopharmaceuticals, its coordination chemistry with the fluorido ligand is by far less explored than that of other ligands. Up to now, only a few technetium fluorides are known. This thesis contains the synthesis, spectroscopic and structural characterization of novel technetium fluorides in the oxidation states ''+1'', ''+2'', ''+4'' and ''+6''. In the oxidation state ''+6'', the fluoridotechnetates were synthesized either from nitridotechnetic(VI) acid or from pertechnetate by using reducing agent and have been isolated as cesium or tetraethylammonium salts. The compounds were characterized spectroscopically and structurally. In the intermediate oxidation state ''+4'', hexafluoridotechnetate(IV) was known for long time and studied spectroscopically. This thesis reports novel and improved syntheses and solved the critical issues of early publications such as the color, some spectroscopic properties and the structure of this key compound. Single crystal analyses of alkali metal, ammonium and tetramethylammonium salts of hexafluoridotechnetate(IV) are presented. In aqueous alkaline solutions, the ammonium salt of hexafluoridotechnetate(IV) undergoes hydrolysis and forms an oxido-bridged dimeric complex. It is the first step hydrolysis product of hexafluoridotechnetate(IV) and was characterized by spectroscopic and crystallographic methods. Low-valent technetium fluorides with the metal in the oxidation states of ''+2'' or ''+1'' are almost unknown. A detailed description of the synthesis and characterization of pentafluoridonitrosyltechnetate(II) is presented. The

  7. Fluoride Rinses, Gels and Foams

    DEFF Research Database (Denmark)

    Twetman, Svante; Keller, Mette K

    2016-01-01

    AIM: The aim of this conference paper was to systematically review the quality of evidence and summarize the findings of clinical trials published after 2002 using fluoride mouth rinses, fluoride gels or foams for the prevention of dental caries. METHODS: Relevant papers were selected after...... (6 on fluoride mouth rinse, 10 on fluoride gel and 3 on fluoride foam); 6 had a low risk of bias while 2 had a moderate risk. All fluoride measures appeared to be beneficial in preventing crown caries and reversing root caries, but the quality of evidence was graded as low for fluoride mouth rinse......, moderate for fluoride gel and very low for acidulated fluoride foam. No conclusions could be drawn on the cost-effectiveness. CONCLUSIONS: This review, covering the recent decade, has further substantiated the evidence for a caries-preventive effect of fluoride mouth rinse, fluoride gel and foam...

  8. Molten salt reactors

    International Nuclear Information System (INIS)

    Bouchter, J.C.; Dufour, P.; Guidez, J.; Simon, N.; Renault, C.

    2014-01-01

    Molten salt reactors are one of the 6 concepts retained for the 4. generation of nuclear reactors. The principle of this reactor is very innovative: the nuclear fuel is dissolved in the coolant which allows the online reprocessing of the fuel and the online recovery of the fission products. A small prototype: the Molten Salt Reactor Experiment (MSRE - 8 MWt) was operating a few years in the sixties in the USA. The passage towards a fast reactor by the suppression of the graphite moderator leads to the concept of Molten Salt Fast Reactor (MSFR) which is presently studied through different European projects such as MOST, ALISIA and EVOL. Worldwide the main topics of research are: the adequate materials resisting to the high level of corrosiveness of the molten salts, fuel salt reprocessing, the 3-side coupling between neutron transport, thermohydraulics and thermo-chemistry, the management of the changing chemical composition of the salt, the enrichment of lithium with Li 7 in the case of the use of lithium fluoride salt and the use of MSFR using U 233 fuel (thorium cycle). The last part of the article presents a preliminary safety analysis of the MSFR. (A.C.)

  9. Fluoride varnishes and enamel caries

    NARCIS (Netherlands)

    Bruyn, Hugo de

    1987-01-01

    Topical fluoride applications have the aim of increasing the fluoride uptake in enamel and consequently reducing caries. In the early ‘60s fluoride varnishes were introduced because they had a long contact period with the enamel which resulted in a higher fluoride uptake than from other topical

  10. Cation and anion dependence of stable geometries and stabilization energies of alkali metal cation complexes with FSA(-), FTA(-), and TFSA(-) anions: relationship with physicochemical properties of molten salts.

    Science.gov (United States)

    Tsuzuki, Seiji; Kubota, Keigo; Matsumoto, Hajime

    2013-12-19

    Stable geometries and stabilization energies (Eform) of the alkali metal complexes with bis(fluorosulfonyl)amide, (fluorosulfonyl)(trifluoromethylslufonyl)amide and bis(trifluoromethylsulfonyl)amide (FSA(-), FTA(-) and TFSA(-)) were studied by ab initio molecular orbital calculations. The FSA(-) complexes prefer the bidentate structures in which two oxygen atoms of two SO2 groups have contact with the metal cation. The FTA(-) and TFSA(-) complexes with Li(+) and Na(+) prefer the bidentate structures, while the FTA(-) and TFSA(-) complexes with Cs(+) prefer tridentate structures in which the metal cation has contact with two oxygen atoms of an SO2 group and one oxygen atom of another SO2 group. The two structures are nearly isoenergetic in the FTA(-) and TFSA(-) complexes with K(+) and Rb(+). The magnitude of Eform depends on the alkali metal cation significantly. The Eform calculated for the most stable TFSA(-) complexes with Li(+), Na(+), K(+), Rb(+) and Cs(+) cations at the MP2/6-311G** level are -137.2, -110.5, -101.1, -89.6, and -84.1 kcal/mol, respectively. The viscosity and ionic conductivity of the alkali TFSA molten salts have strong correlation with the magnitude of the attraction. The viscosity increases and the ionic conductivity decreases with the increase of the attraction. The melting points of the alkali TFSA and alkali BETA molten salts also have correlation with the magnitude of the Eform, which strongly suggests that the magnitude of the attraction play important roles in determining the melting points of these molten salts. The anion dependence of the Eform calculated for the complexes is small (less than 2.9 kcal/mol). This shows that the magnitude of the attraction is not the cause of the low melting points of alkali FTA molten salts compared with those of corresponding alkali TFSA molten salts. The electrostatic interactions are the major source of the attraction in the complexes. The electrostatic energies for the most stable TFSA

  11. Community-oriented administration of fluoride for the prevention of dental caries

    DEFF Research Database (Denmark)

    Petersen, P E; Baez, R J; Lennon, M A

    2012-01-01

    Dental caries is the most prevalent chronic disease affecting human populations around the world. It is recognized that fluoride plays a significant role in dental caries reduction. Meanwhile, several low- and middle-income countries of Asia have not yet implemented systematic fluoride programs...... coverage. Participants acknowledged that automatic fluoridation through water, salt, and milk is the most effective and equitable strategy for the prevention of dental caries. Concerns were expressed that government-subsidized community fluoride prevention programs may face privatization. In addition...... need further dissemination. The meeting was co-sponsored by the World Health Organization, the International Association for Dental Research, and the World Dental Federation....

  12. Deposition of niobium plate on niobium-titanium from molten salts

    International Nuclear Information System (INIS)

    Matychenko, Eh.S.; Shevyrev, A.A.; Stolyarova, L.A.; Sukhorzhevskaya, S.L.

    1993-01-01

    A possibility of using Nb-Ti alloys (50 and 34 mas.% of Ti) as substrates for deposition of niobium coating of chloride-fluoride and fluoride molten salts is studied. Corrosion behaviour of alloys indicates in the electrolytic bath within 970-1070 K interval, coating structure and state of coating-substrate boundary are investigated. Chloride-fluoride molten salt usefullness for making products with niobium coatings is shown

  13. The cariostatic mechanisms of fluoride

    OpenAIRE

    Kata Rošin-Grget; Kristina Peroš; Ivana Šutej; Krešimir Bašić

    2013-01-01

    This article discusses the possible cariostatic mechanisms of the action of fluoride. In the past, fluoride inhibition of caries was ascribed to reduced solubility of enamel due to incorporation of fluoride (F–) into the enamel minerals. The present evidence from clinical and laboratory studies suggests that the caries-preventive mode of action of fluoride is mainly topical. There is convincing evidence that fluoride has a major effect on demineralisation and remineralisation of dental hard t...

  14. The effect of addition of primary positive salts, complex salt, on the ionic strength and rate constant at various temperatures by reaction kinetics

    Science.gov (United States)

    Kurade, S. S.; Ramteke, A. A.

    2018-05-01

    In this work, we have investigated the rate of reaction by using ionic strength at different temperatures. The main goal of this experiment is to determine the relation between ionic strength with reaction rate, reaction time and rate constant with temperature. It is observed that the addition of positive salt indicate the increasing ionic strength with increase in run time at various temperatures. Thus the temperature affects the speed of reaction and mechanism by which chemical reaction occurs and time variable plays vital role in the progress of reaction at different temperatures.

  15. System Requirements Document for the Molten Salt Reactor Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Aigner, R.D.

    2000-04-01

    The purpose of the conversion process is to convert the {sup 233}U fluoride compounds that are being extracted from the Molten Salt Reactor Experiment (MSRE) equipment to a stable oxide for long-term storage at Bldg. 3019.

  16. The prevalence of fluorosis in children is associated with naturally occurring water fluoride concentration in Mexico.

    Science.gov (United States)

    Mariño, Rodrigo

    2013-09-01

    Fluorosis and dental caries in Mexican schoolchildren residing in areas with different water fluoride concentrations and receiving fluoridated salt. Garcia-Perez A, Irigoyen-Carnacho ME, Borges-Yanez A. Caries Res 2013;47(4):299-308. Rodrigo Mariño Is there an association between the presence of dental fluorosis and fluoride concentration in drinking water? and Is there an association between the severity of fluorosis and dental caries experience in schoolchildren residing in two rural towns in Mexico (with water fluoride concentrations of 0.70 and 1.50 ppm) that also receive fluoridated salt? Government: National Council of Science and Technology (Consejo Nacional de Ciencia y Tecnologia, CONACYT) Other: Autonomous University, Xochimilco (Universidad Autonoma Metropolitana, UAM-X) TYPE OF STUDY/DESIGN: Cross-sectional Level 3: Other evidence Not applicable. Copyright © 2013 Elsevier Inc. All rights reserved.

  17. Fluoride reactions with dental enamel following different forms of fluoride supply

    International Nuclear Information System (INIS)

    Hellstroem, I.; Ericsson, Y.

    1976-01-01

    The reactions with dental enamel of NaF as tablets dissolved in different beverages or supplied with NaCl, simulating domestic salt fluoridation, were studied in tests with enamel surfaces and enamel powder. It was confirmed that powdered enamel can react quite differently from enamel surfaces under certain conditions. Enamel surfaces took up much more fluoride (F) from orange juice than from water or milk, and neither the low pH nor the citrate content of the juice increased the formation of unstable CaF 2 in the enamel, as judged from a KOH leaching test. The F uptake by enamel surfaces from 0.25 mM NaF in 175 mM NaCl, corresponding to a dish prepared with salt containing 500 parts/10 6 F, was about 80 percent greater than from the same NaF concentration in water. This NaCl concentration did not increase the formation of CaF 2 in the enamel, as judged from the KOH test, while 350 mM NaCl caused a moderate increase. The investigations support the administration of NaF tablets with orange juice and the plans for domestic salt fluoridation. (author)

  18. Preparation of bromine fluoride

    International Nuclear Information System (INIS)

    Domange, Pr; Duflo, J.

    1958-05-01

    This note addresses the preparation of bromine fluoride. It indicates the implemented process for the reaction, used products (fluorine and bromine), and column characteristics. It describes the operating mode. Apparatus drawing is provided

  19. Uranium fluorides analysis. Titanium spectrophotometric determination

    International Nuclear Information System (INIS)

    Anon.

    Titanium determination in uranium hexafluoride in the range 0.7 to 100 microgrammes after transformation of uranium fluoride in sulfate. Titanium is separated by extraction with N-benzoylphenylhydroxylamine, reextracted by hydrochloric-hydrofluoric acid. The complex titanium-N-benzoylphenylhydroxylamine is extracted by chloroform. Spectrophotometric determination at 400 nm [fr

  20. Field method for estimation of fluoride in drinking groundwater by photometric measurement of spot on aluminium quinalizarin reagent paper

    OpenAIRE

    Zaher Barghouthi; Sameer Amereih

    2017-01-01

    A simple field method for determination of fluoride in drinking water using handmade fluoride reagent paper impregnated by aluminium quinalizarin complex was developed. Fluoride reacts with the impregnated reagent paper to release the free ligand with new colour, orange different from that of the complex. The change in the colour, which is proportional to the amount of fluoride, was measured by the Arsenator. The functionality of the Arsenator which is based on a photometric measurement of sp...

  1. Synthesis of 2-deoxy-2,2-difluoro-α-maltosyl fluoride and its X-ray structure in complex with Streptomyces coelicolor GlgEI-V279S

    Energy Technology Data Exchange (ETDEWEB)

    Thanna, Sandeep; Lindenberger, Jared J.; Gaitonde, Vishwanath V.; Ronning, Donald R.; Sucheck, Steven J. (Toledo)

    2015-06-05

    Streptomyces coelicolor (Sco) GlgEI is a glycoside hydrolase involved in α-glucan biosynthesis and can be used as a model enzyme for structure-based inhibitor design targeting Mycobacterium tuberculosis (Mtb) GlgE. The latter is a genetically validated drug target for the development of anti-Tuberculosis (TB) treatments. Inhibition of Mtb GlgE results in a lethal buildup of the GlgE substrate maltose-1-phosphate (M1P). However, Mtb GlgE is difficult to crystallize and affords lower resolution X-ray structures. Sco GlgEI-V279S on the other hand crystallizes readily, produces high resolution X-ray data, and has active site topology identical to Mtb GlgE. We report the X-ray structure of Sco GlgEI-V279S in complex with 2-deoxy-2,2-difluoro-α-maltosyl fluoride (α-MTF, 5) at 2.3 Å resolution. α-MTF was designed as a non-hydrolysable mimic of M1P to probe the active site of GlgE1 prior to covalent bond formation without disruption of catalytic residues. The α-MTF complex revealed hydrogen bonding between Glu423 and the C1F which provides evidence that Glu423 functions as proton donor during catalysis. Further, hydrogen bonding between Arg392 and the axial C2 difluoromethylene moiety of α-MTF was observed suggesting that the C2 position tolerates substitution with hydrogen bond acceptors. The key step in the synthesis of α-MDF was transformation of peracetylated 2-fluoro-maltal 1 into peracetylated 2,2-difluoro-α-maltosyl fluoride 2 in a single step via the use of Selectfluor®

  2. A binary catalyst system of a cationic Ru-CNC pincer complex with an alkali metal salt for selective hydroboration of carbon dioxide.

    Science.gov (United States)

    Ng, Chee Koon; Wu, Jie; Hor, T S Andy; Luo, He-Kuan

    2016-09-27

    Binary catalyst systems comprising a cationic Ru-CNC pincer complex and an alkali metal salt were developed for selective hydroboration of CO 2 utilizing pinacolborane at r.t. and 1 atm CO 2 , with the combination of [Ru(CNC Bn )(CO) 2 (H)][PF 6 ] and KOCO 2 t Bu producing formoxyborane in 76% yield. A bicyclic catalytic mechanism was proposed and discussed.

  3. Water Fluoridation Statistics - Percent of PWS population receiving fluoridated water

    Data.gov (United States)

    U.S. Department of Health & Human Services — 2000-2014. Water Fluoridation Statistics is a biennial report of the percentage and number of people receiving fluoridated water from 2000 through 2014, originally...

  4. Water Fluoridation Statistics - Percent of PWS population receiving fluoridated water

    Data.gov (United States)

    U.S. Department of Health & Human Services — 2000-2014 Water Fluoridation Statistics is a biennial report of the percentage and number of people receiving fluoridated water from 2000 through 2014, originally...

  5. Hot filament technique for measuring the thermal conductivity of molten lithium fluoride

    Science.gov (United States)

    Jaworske, Donald A.; Perry, William D.

    1990-01-01

    Molten salts, such as lithium fluoride, are attractive candidates for thermal energy storage in solar dynamic space power systems because of their high latent heat of fusion. However, these same salts have poor thermal conductivities which inhibit the transfer of heat into the solid phase and out of the liquid phase. One concept for improving the thermal conductivity of the thermal energy storage system is to add a conductive filler material to the molten salt. High thermal conductivity pitch-based graphite fibers are being considered for this application. Although there is some information available on the thermal conductivity of lithium fluoride solid, there is very little information on lithium fluoride liquid, and no information on molten salt graphite fiber composites. This paper describes a hot filament technique for determining the thermal conductivity of molten salts. The hot filament technique was used to find the thermal conductivity of molten lithium fluoride at 930 C, and the thermal conductivity values ranged from 1.2 to 1.6 W/mK. These values are comparable to the slightly larger value of 5.0 W/mK for lithium fluoride solid. In addition, two molten salt graphite fiber composites were characterized with the hot filament technique and these results are also presented.

  6. The cariostatic mechanisms of fluoride

    Directory of Open Access Journals (Sweden)

    Kata Rošin-Grget

    2013-11-01

    Full Text Available This article discusses the possible cariostatic mechanisms of the action of fluoride. In the past, fluoride inhibition of caries was ascribed to reduced solubility of enamel due to incorporation of fluoride (F– into the enamel minerals. The present evidence from clinical and laboratory studies suggests that the caries-preventive mode of action of fluoride is mainly topical. There is convincing evidence that fluoride has a major effect on demineralisation and remineralisation of dental hard tissue. The source of this fluoride could either be fluorapatite (formed due to the incorporation of fluoride into enamel or calcium fluoride (CaF2-like precipitates, which are formed on the enamel and in the plaque after application of topical fluoride. Calcium fluoride deposits are protected from rapid dissolution by a phosphate –protein coating of salivary origin. At lower pH, the coating is lost and an increased dissolution rate of calcium fluoride occurs. The CaF2, therefore, act as an efficient source of free fluoride ions during the cariogenic challenge. The current evidence indicates that fluoride has a direct and indirect effect on bacterial cells, although the in vivo implications of this are still not clear. Conclusion. A better understanding of the mechanisms of the action of fluoride is very important for caries prevention and control. The effectiveness of fluoride as a cariostatic agent depends on the availability of free fluoride in plaque during cariogenic challenge, i.e. during acid production. Thus, a constant supply of low levels of fluoride in biofilm/saliva/dental interference is considered the most beneficial in preventing dental caries.

  7. The cariostatic mechanisms of fluoride.

    Science.gov (United States)

    Rošin-Grget, Kata; Peroš, Kristina; Sutej, Ivana; Bašić, Krešimir

    2013-11-01

    This article discusses the possible cariostatic mechanisms of the action of fluoride. In the past, fluoride inhibition of caries was ascribed to reduced solubility of enamel due to incorporation of fluoride (F-) into the enamel minerals. The present evidence from clinical and laboratory studies suggests that the caries-preventive mode of action of fluoride is mainly topical. There is convincing evidence that fluoride has a major effect on demineralisation and remineralisation of dental hard tissue. The source of this fluoride could either be fluorapatite (formed due to the incorporation of fluoride into enamel) or calcium fluoride (CaF2)-like precipitates, which are formed on the enamel and in the plaque after application of topical fluoride. Calcium fluoride deposits are protected from rapid dissolution by a phosphate -protein coating of salivary origin. At lower pH, the coating is lost and an increased dissolution rate of calcium fluoride occurs. The CaF2, therefore, act as an efficient source of free fluoride ions during the cariogenic challenge. The current evidence indicates that fluoride has a direct and indirect effect on bacterial cells, although the in vivo implications of this are still not clear. A better understanding of the mechanisms of the action of fluoride is very important for caries prevention and control. The effectiveness of fluoride as a cariostatic agent depends on the availability of free fluoride in plaque during cariogenic challenge, i.e. during acid production. Thus, a constant supply of low levels of fluoride in biofilm/saliva/dental interference is considered the most beneficial in preventing dental caries. Copyright © 2013 by Academy of Sciences and Arts of Bosnia and Herzegovina.

  8. Pyrochemical recovery of plutonium fluoride reduction slag

    International Nuclear Information System (INIS)

    Christensen, D.C.; Rayburn, J.A.

    1983-07-01

    A process was developed for the pyrochemical recovery of plutonium from residues resulting from the PuF 4 reduction process. The process involves crushing the CaF 2 slag and dissolving it at 800 0 C in a CaCl 2 solvent. The plutonium, which exists either as finely divided metal or as incompletely reduced fluoride salt, is reduced to metal and/or allowed to coalesce as a massive button in the bottom of the reaction crucible. The recovery of plutonium in a 1-day cycle averaged 96%; all of the resulting residues were discardable

  9. Electrorecovery of tantalum in molten fluorides

    International Nuclear Information System (INIS)

    Espinola, A.; Dutra, A.J.B.; Silva, F.T. da

    1988-01-01

    Considering the privileged situation of Brazil as a productor of tantaliferous minerals, the authors have in view the development of a technology for production of metallic tantalum via molten salts electrolysis; this has the advantage of improving the aggregate value of exportation products, additionally to tantalum oxide and tantalum concentrates. Having in view the preliminary determintion of better conditions of temperature, electrolyte composition and current density for this process, electrolysis were conducted with a solvent composed of an eutetic mixture of lithium, sodium and potassium fluoride for dipotassium fluotantalate and occasionally for tantalum oxide. Current efficiencies as high as 83% were obtained in favoured conditions. (author) [pt

  10. Selective Complexation of Cyanide and Fluoride Ions with Ammonium Boranes: A Theoretical Study on Sensing Mechanism Involving Intramolecular Charge Transfer and Configurational Changes.

    Science.gov (United States)

    Bhat, Haamid R; Jha, Prakash C

    2017-05-18

    The anion binding selectivity and the recognition mechanism of two isomeric boranes, namely, 4-[bis(2,4,6-trimethylphenyl)boranyl]-N,N,N-trimethylaniline ([p-(Mes 2 B)C 6 H 4 (NMe 3 )] + , 1, where "Mes" represents mesitylene and "Me" represents methyl) and 2-[bis(2,4,6-trimethylphenyl)boranyl]-N,N,N-trimethylaniline ([o-(Mes 2 B)C 6 H 4 (NMe 3 )] + , 2) has been investigated using density functional theory (DFT) and time dependent-density functional theory (TD-DFT) methods. Natural population analysis indicates that the central boron atoms in 1 and 2 are the most active centers for nucleophilic addition of anions. The negative magnitude of free energy changes (ΔG) reveals that out of CN - , F - , Cl - , Br - , NO 3 - , and HSO 4 - only the binding of CN - and F - with 1 and 2 is thermodynamically feasible and spontaneous. In addition, the calculated binding energies reveal that the CN - is showing lesser binding affinity than F - both with 1 and 2, while other ions, viz. NO 3 - , HSO 4 - , Br - , and Cl - , either do not bind at all or show very insignificant binding energy. The first excited states (S 1 ) of 1 and 2 are shown to be the local excited states with π → σ* transition by frontier molecular orbital analysis, whereas fourth excited states (S 4 ) of 4-[bis(2,4,6-trimethylphenyl)boranyl]-N,N,N-trimethylaniline cyanide ([p-(Mes 2 B)C 6 H 4 (NMe 3 )] CN, 1CN, the cyano form of 1) and 4-[bis(2,4,6-trimethylphenyl)boranyl]-N,N,N-trimethylaniline fluoride ([p-(Mes 2 B)C 6 H 4 (NMe 3 )] F, 1F, the fluoro form of 1) and fifth excited state (S 5 ) of 2-[bis(2,4,6-trimethylphenyl)boranyl]-N,N,N-trimethylaniline fluoride ([o-(Mes 2 B)C 6 H 4 (NMe 3 )] F, 2F, the fluoro form of 2) are charge separation states that are found to be responsible for the intramolecular charge transfer (ICT) process. The synergistic effect of ICT and partial configuration changes induce fluorescence quenching in 1CN, 1F, and 2F after a significant internal conversion (IC) from S 4 and

  11. Fluoride and Water (For Parents)

    Science.gov (United States)

    ... risk of tooth decay" on the label. The Controversy Over Fluoride Opponents of water fluoridation have questioned ... Us Contact Us Partners Editorial Policy Permissions Guidelines Privacy Policy & Terms of Use Notice of Nondiscrimination Visit ...

  12. Recovery of protactinium from molten fluoride nuclear fuel compositions

    Science.gov (United States)

    Baes, C.F. Jr.; Bamberger, C.; Ross, R.G.

    1973-12-25

    A method is provided for separating protactinium from a molten fluonlde salt composition consisting essentially of at least one alkali and alkaline earth metal fluoride and at least one soluble fluoride of uranium or thorium which comprises oxidizing the protactinium in said composition to the + 5 oxidation state and contacting said composition with an oxide selected from the group consisting of an alkali metal oxide, an alkaline earth oxide, thorium oxide, and uranium oxide, and thereafter isolating the resultant insoluble protactinium oxide product from said composition. (Official Gazette)

  13. IUPAC-NIST Solubility Data Series. 100. Rare Earth Metal Fluorides in Water and Aqueous Systems. Part 3. Heavy Lanthanides (Gd–Lu)

    Energy Technology Data Exchange (ETDEWEB)

    Mioduski, Tomasz [Institute of Nuclear Chemistry and Technology, 03195 Warszawa (Poland); Gumiński, Cezary, E-mail: cegie@chem.uw.edu.pl [Department of Chemistry, University of Warsaw, 02093 Warszawa (Poland); Zeng, Dewen, E-mail: dewen-zeng@hotmail.com [College of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China)

    2015-06-15

    This is the third part of the volume devoted to solubility data for the rare earth metal (REM) fluorides in water and in aqueous ternary and multicomponent systems. It covers experimental results of trivalent fluorides of Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu (so-called heavy lanthanides), since no quantitative data on solubilities of TbF{sub 4} and YbF{sub 2} (the most stable compounds at these valencies) are available. The related literature has been covered through the end of 2014. Compilations of all available papers with the solubility data are introduced for each REM fluoride with a corresponding critical evaluation. Every such assessment contains a collection of all solubility results in aqueous solution, a selection of suggested solubility data, a solubility equation, and a brief discussion of the multicomponent systems. Only simple fluorides (no complexes or double salts) are treated as the input substances in this report. General features of the systems, such as nature of the equilibrium solid phases, solubility as a function of temperature, influence of ionic strength, solution pH, mixed solvent medium on the solubility, quality of the solubility results, and the solubility as a function of REM atomic number, have already been presented in Part 1 of the volume.

  14. Fluoride resistance in Streptococcus mutans

    NARCIS (Netherlands)

    Liao, Ying

    2017-01-01

    Fluoride has been used as the most effective anti-caries agent for over five decades. It functions not only on the dental hard tissues, but also as an antimicrobial agent. It is known that oral bacteria are able to develop resistance to fluoride, which may affect the effectiveness of fluoride in

  15. Assessment of Candidate Molten Salt Coolants for the Advanced High Temperature Reactor (AHTR)

    Energy Technology Data Exchange (ETDEWEB)

    Williams, D.F.

    2006-03-24

    exhibit better heat transfer and nuclear performance metrics. Lighter salts also tend to have more favorable (larger) moderating ratios, and thus should have a more favorable coolant-voiding behavior in-core. Heavy (high-Z) salts tend to have lower heat capacities and thermal conductivities and more significant activation and transmutation products. However, all of the salts are relatively good heat-transfer agents. A detailed discussion of each property and the combination of properties that served as a heat-transfer metric is presented in the body of this report. In addition to neutronic metrics, such as moderating ratio and neutron absorption, the activation properties of the salts were investigated (Table C). Again, lighter salts tend to have more favorable activation properties compared to salts with high atomic-number constituents. A simple model for estimating the reactivity coefficients associated with a reduction of salt content in the core (voiding or thermal expansion) was also developed, and the primary parameters were investigated. It appears that reasonable design flexibility exists to select a safe combination of fuel-element design and salt coolant for most of the candidate salts. Materials compatibility is an overriding consideration for high-temperature reactors; therefore the question was posed whether any one of the candidate salts was inherently, or significantly, more corrosive than another. This is a very complex subject, and it was not possible to exclude any fluoride salts based on the corrosion database. The corrosion database clearly indicates superior container alloys, but the effect of salt identity is masked by many factors which are likely more important (impurities, redox condition) in the testing evidence than salt identity. Despite this uncertainty, some reasonable preferences can be recommended, and these are indicated in the conclusions. The reasoning to support these conclusions is established in the body of this report.

  16. Complexation of triptycene-derived macrotricyclic polyether with paraquat derivatives, diquat, and a 2,7-diazapyrenium salt: guest-induced conformational changes of the host.

    Science.gov (United States)

    Han, Ying; Cao, Jing; Li, Peng-Fei; Zong, Qian-Shou; Zhao, Jian-Min; Guo, Jia-Bin; Xiang, Jun-Feng; Chen, Chuan-Feng

    2013-04-05

    Complexation between a triptycene-derived macrotricyclic polyether containing two dibenzo-[30]-crown-10 cavities and different functionalized paraquat derivatives, diquat, and a 2,7-diazapyrenium salt in both solution and solid state was investigated in detail. It was found that depending on the guests with different terminal functional groups and structures, the macrotricyclic polyether could form 1:1 or 1:2 complexes with the guests in different complexation modes in solution and also in the solid state. Especially, the conformation of the macrotricyclic polyether was efficiently adjusted by the encapsulated guests, which was to some extent similar to substrate-induced fit of enzymes. Moreover, the binding and releasing of the guests in the complexes could be controlled by potassium ions.

  17. Urinary fluoride excretion after application of fluoride varnish and use of fluoride toothpaste in young children

    DEFF Research Database (Denmark)

    Lockner, Frida; Twetman, Svante; Stecksén-Blicks, Christina

    2017-01-01

    BACKGROUND: The efficacy and safety of combined use of topical fluoride products are essential issues that must be monitored. AIM: To assess urinary excretion of fluoride after application of two different dental varnishes containing 2.26% fluoride in 3- to 4-year-old children and to compare...... the levels with and without parallel use of fluoride toothpaste. DESIGN: Fifteen healthy children were enrolled to a randomized crossover trial that was performed in two parts: Part I with twice-daily tooth brushing with fluoride toothpaste and Part II with twice-daily brushing with a non-fluoride toothpaste....... After a 1-week run-in period, 0.1 mL of the two fluoride varnishes (Duraphat and Profluorid Varnish) was topically applied in a randomized order. Baseline and experimental urine was collected during 6-h periods. The fluoride content was determined with an ion-sensitive electrode. RESULTS...

  18. Salt Selection for the LS-VHTR

    International Nuclear Information System (INIS)

    Williams, D.F.; Clarno, K.T.

    2006-01-01

    Molten fluorides were initially developed for use in the nuclear industry as the high temperature fluid-fuel for a Molten Salt Reactor (MSR). The Office of Nuclear Energy is exploring the use of molten fluorides as a primary coolant (rather than helium) in an Advanced High Temperature Reactor (AHTR) design, also know as the Liquid-Salt cooled Very High Temperature Reactor (LS-VHTR). This paper provides a review of relevant properties for use in evaluation and ranking of candidate coolants for the LS-VHTR. Nuclear, physical, and chemical properties were reviewed and metrics for evaluation are recommended. Chemical properties of the salt were examined for the purpose of identifying factors that effect materials compatibility (i.e., corrosion). Some preliminary consideration of economic factors for the candidate salts is also presented. (authors)

  19. Fluoride release from fluoride varnishes under acidic conditions.

    Science.gov (United States)

    Lippert, F

    2014-01-01

    The aim was to investigate the in vitro fluoride release from fluoride varnishes under acidic conditions. Poly(methyl methacrylate) blocks (Perspex, n=3 per group) were painted with 80 ± 5 mg fluoride varnish (n=10) and placed into artificial saliva for 30 min. Then, blocks were placed into either 1% citric acid (pH 2.27) or 0.3% citric acid (pH 3.75) solutions (n=3 per solution and varnish) for 30 min with the solutions being replaced every 5 min. Saliva and acid solutions were analyzed for fluoride content. Data were analyzed using three-way ANOVA (varnish, solution, time). The three-way interaction was significant (p>0.0001). Fluoride release and release patterns varied considerably between varnishes. Fluoride release in saliva varied by a factor of more than 10 between varnishes. Some varnishes (CavityShield, Nupro, ProFluorid, Vanish) showed higher fluoride release in saliva than during the first 5 min of acid exposure, whereas other varnishes (Acclean, Enamel-Pro, MI Varnish, Vella) showed the opposite behavior. There was little difference between acidic solutions. Fluoride release from fluoride varnishes varies considerably and also depends on the dissolution medium. Bearing in mind the limitations of laboratory research, the consumption of acidic drinks after fluoride varnish application should be avoided to optimize the benefit/risk ratio.

  20. Small molecule fluoride toxicity agonists.

    Science.gov (United States)

    Nelson, James W; Plummer, Mark S; Blount, Kenneth F; Ames, Tyler D; Breaker, Ronald R

    2015-04-23

    Fluoride is a ubiquitous anion that inhibits a wide variety of metabolic processes. Here, we report the identification of a series of compounds that enhance fluoride toxicity in Escherichia coli and Streptococcus mutans. These molecules were isolated by using a high-throughput screen (HTS) for compounds that increase intracellular fluoride levels as determined via a fluoride riboswitch reporter fusion construct. A series of derivatives were synthesized to examine structure-activity relationships, leading to the identification of compounds with improved activity. Thus, we demonstrate that small molecule fluoride toxicity agonists can be identified by HTS from existing chemical libraries by exploiting a natural fluoride riboswitch. In addition, our findings suggest that some molecules might be further optimized to function as binary antibacterial agents when combined with fluoride. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Fluoride retention by kaolin clay

    DEFF Research Database (Denmark)

    Kau, P. M. H.; Smith, D. W.; Binning, Philip John

    1997-01-01

    To evaluate the potential effectiveness of kaolin clay liners in storage of fluoride contaminated waste, an experimental study of the sorption and desorption behaviour of fluoride in kaolin clay was conducted. The degree of fluoride sorption by kaolin was found to depend on solution p......H and available fluoride concentration with equilibrium being achieved within 24 h. A site activation process involving the uptake of fluoride was also observed at the initial stages of sorption. This behaviour was attributed to a layer expansion process of the clay during sorption. The maximum fluoride sorption...... capacity was found to be 18.3 meq/100 g at pH 6 and 8.6 meq/100 g at pH 7. A competitive Langmuir sorption isotherm where sorption is dependant on both pH and fluoride concentration is employed to characterise the experimental sorption and desorption data. The sorption and desorption isotherms revealed...

  2. Fluoride and Oral Health

    DEFF Research Database (Denmark)

    O'Mullane, D M; Baez, R J; Jones, S

    2016-01-01

    and strategies is noteworthy. This updated version of ‘Fluoride and Oral Health’ has adopted an evidence-based approach to its commentary on the different fl uoride vehicles and strategies and also to its recommendations. In this regard, full account is taken of the many recent systematic reviews published...

  3. Direct photometric determination of fluorides in potassium chloride and iodide

    International Nuclear Information System (INIS)

    Dedkova, V.P.; Savvin, S.B.

    1985-01-01

    An attempt is made to apply the technique of determining fluorides with xylenol orange and sulfochlorophenol S as being the most sensitive in the analysis of of fiber optics. It is known that an increase of the sensitivity of the determination can be achieved on increasing the sample size of the substance to be analyzed, and the length of the absorbing layer. However, a high salt background may have a strong influence on the course of the reaction, and a supplementary of this effect is mad. Potassium chloride and iodide were selected as model compounds. A direct photometric procedure is proposed for determining fluorides in the samples, with a determination limit of 5 x 10 -6 %. Such a low determination limit is achieved by increasing the sample weight to 3 g, by increasing the length of the absorbing layer in the cell to 50 mm, and by using a highly sensitive reaction for determining fluorides with zirconium and xylenol orange

  4. Improvement to molten salt reactors

    International Nuclear Information System (INIS)

    Bienvenu, Claude.

    1975-01-01

    The invention proposes a molten salt nuclear reactor whose core includes a mass of at least one fissile element salt to which can be added other salts to lower the melting temperature of the mass. This mass also contains a substance with a low neutron capture section that does not give rise to a chemical reaction or to an azeotropic mixture with these salts and having an atmospheric boiling point under that of the mass in operation. Means are provided for collecting this substance in the vapour state and returning it as a liquid to the mass. The kind of substance chosen will depend on that of the molten salts (fissile element salts and, where required, salts to lower the melting temperature). In actual practice, the substance chosen will have an atmospheric pressure boiling point of between 600 and 1300 0 C and a melting point sufficiently below 600 0 C to prevent solidification and clogging in the return line of the substance from the exchanger. Among the materials which can be considered for use, mention is made of magnesium, rubidium, cesium and potassium but metal cesium is not employed in the case of many fissile salts, such as fluorides, which it would reduced to the planned working temperatures [fr

  5. Formation of nitrogen complexes when [Ru(NH3)5H2O]2+ ion reaction with diazo-acetic ester and aromatic salts of diazonium

    International Nuclear Information System (INIS)

    Shur, V.B.; Tikhonova, I.A.; Vol'pin, M.E.

    1978-01-01

    A possibility of formation of nitrogen complexes during transition metal compound interaction with aliphatic and aromatic diazo compounds is studied. It is shown that at the interaction of [Ru(NH 3 ) 5 H 2 O] 2+ with diazo-acetic ester in water (pH7) at 20 deg, quick splitting of the CN-bond in the ester molecule takes place with the formation of [Ru(NH 3 ) 5 N 2 ] 2+ and [(NH 3 ) 5 RuN 2 Ru(NH 3 ) 5 ] 4+ (NRRN) nitrogen complexes. The sum yield of complexes comprises 86% taking into acount diazo-acetic ester. Aromatic salts of diazonium, n-O 3 SC 6 H 4 N 2 and p-quinone diazide react with the [Ru(NH 3 ) 5 H 2 O] 2+ excess forming NRRN (the yield equals 40-53%). The reaction mechanism is discussed

  6. Indian programme on molten salt cooled nuclear reactors

    International Nuclear Information System (INIS)

    DuIera, I.V.; Vijayan, P.K.; Sinha, R.K.

    2013-01-01

    Bhabha Atomic Research Centre (BARC) is developing a 600 MWth pebble bed high temperature reactor, cooled by natural circulation of molten fluoride salts and is capable of supplying process heat at 1000 ℃ to facilitate hydrogen production by splitting water. BARC has also initiated studies for a reactor concept in which salts of molten fluoride fuel and coolant in fluid form, flows through the reactor core of graphite moderator, resulting in nuclear fission within the molten salt. For thorium fuel cycle, this concept is very attractive, since the fuel can be re-processed on-line, enabling it to be an efficient neutron breeder. (author)

  7. Metallic materials corrosion problems in molten salt reactors

    International Nuclear Information System (INIS)

    Chauvin, G.; Dixmier, J.; Jarny, P.

    1977-01-01

    The USA forecastings concerning the molten salt reactors are reviewed (mixtures of fluorides containing the fuel, operating between 560 and 700 0 C). Corrosion problems are important in these reactors. The effects of certain characteristic factors on corrosion are analyzed: humidity and metallic impurities in the salts, temperature gradients, speed of circulation of salts, tellurium from fission products, coupling. In the molten fluorides and experimental conditions, the materials with high Ni content are particularly corrosion resistant alloys (hastelloy N). The corrosion of this material is about 2.6 mg.cm -2 at 700 0 C [fr

  8. Thermodynamic stability of complexes of BF3, PF5 and AsF5 with chlorine fluorides, oxyfluorides, and related compounds

    International Nuclear Information System (INIS)

    Trowbridge, L.D.

    1996-07-01

    The recent discovery of solid, water sensitive, arsenic-containing deposits in auxiliary process piping in the PGDP led to a search for explanations that could account for such accumulated material. A plausible explanation for the deposits is the formation of complexes of AsF 5 with one or more gases that may have been present as a result of cascade equipment cleanup activities. A literature search was performed. The target of the search was literature that would provide information on the dissociation pressure of complexes of AsF 5 or its hydrolysis products with any gases that may be (at least intermittently) present in the cascade location where the deposits were found. While the precise information sought (namely reliable, accurate dissociation pressures of such complexes at cascade temperatures) was not found in the detail desired. other information on these or similar complexes was obtained which permits prediction of the conditions under which the complexes might form, dissociate, or migrate, and how they might behave in the presence of atmospheric moisture. Information was gathered on potential AsF 5 complexes with ClF, ClF 3 , ClF 5 , ClF 3 O, ClO 2 F, and ClO 3 F. Information was also collected on many other related complexes as it was encountered, particularly for series of complexes which could assist in predicting chemical trends. Thermodynamic analysis and property estimation methods have been used to generate provisional estimates of the dissociation pressures of the two complexes ClF 3 *AsF 5 and ClO 2 F*AsF 5 . In addition, several hydrolysis species have been identified, and stability properties of the most relevant such complex (H 3 O*AsF 6 ) have similarly been estimated. While the predicted dissociation pressures are somewhat uncertain. they do lead to a tentative picture of the formation and behavior of such complexes in a cascade cleanup environment

  9. Fluoride in weathered rock aquifers of southern India: Managed Aquifer Recharge for mitigation.

    Science.gov (United States)

    Brindha, K; Jagadeshan, G; Kalpana, L; Elango, L

    2016-05-01

    Climatic condition, geology, and geochemical processes in an area play a major role on groundwater quality. Impact of these on the fluoride content of groundwater was studied in three regions-part of Nalgonda district in Telangana, Pambar River basin, and Vaniyar River basin in Tamil Nadu, southern India, which experience semi-arid climate and are predominantly made of Precambrian rocks. High concentration of fluoride in groundwater above 4 mg/l was recorded. Human exposure dose for fluoride through groundwater was higher in Nalgonda than the other areas. With evaporation and rainfall being one of the major contributors for high fluoride apart from the weathering of fluoride rich minerals from rocks, the effect of increase in groundwater level on fluoride concentration was studied. This study reveals that groundwater in shallow environment of all three regions shows dilution effect due to rainfall recharge. Suitable managed aquifer recharge (MAR) methods can be adopted to dilute the fluoride rich groundwater in such regions which is explained with two case studies. However, in deep groundwater, increase in fluoride concentration with increase in groundwater level due to leaching of fluoride rich salts from the unsaturated zone was observed. Occurrence of fluoride above 1.5 mg/l was more in areas with deeper groundwater environment. Hence, practicing MAR in these regions will increase the fluoride content in groundwater and so physical or chemical treatment has to be adopted. This study brought out the fact that MAR cannot be practiced in all regions for dilution of ions in groundwater and that it is essential to analyze the fluctuation in groundwater level and the fluoride content before suggesting it as a suitable solution. Also, this study emphasizes that long-term monitoring of these factors is an important criterion for choosing the recharge areas.

  10. Treatability study of arsenic, fluoride and nitrate from drinking water by adsorption process

    International Nuclear Information System (INIS)

    Abbas, N.; Irfan, M.; Butt, M.T.

    2014-01-01

    Natural contamination of nitrate, fluoride, arsenic and dissolved salts in ground water sources is the main health menace at present in different parts of Pakistan. The metalloids especially arsenic, fluoride and nitrate pose severe health hazards to human being. The present research work investigated the removal techniques for arsenic, fluoride and nitrate from drinking water by adsorption process. Ion exchange resins, activated carbon and activated alumina were used for removal of selected contaminants. These adsorbents were evaluated by comparing their removal efficiency as well as requisite operator skills. The result of activated alumina was found good as compared to activated carbon, mix bed resins and ion exchange resins (IRA-400) for maximum removal of arsenic, nitrate and fluoride. The removal efficiency of arsenic, fluoride and nitrate were found 96%, 99%, 98% respectively in case of activated alumina. The advantage of adsorption process is easy to use and relatively cheaper as compared to other treatment methodologies. (author)

  11. Fluoride Consumption and Its Impact on Oral Health

    Directory of Open Access Journals (Sweden)

    Luis Fernando Jacinto-Alemán

    2011-01-01

    Full Text Available Objective. The purpose of this study was to evaluate caries and dental fluorosis among Mexican preschoolers and school-aged children in a non-endemic zone for fluorosis and to measure its biological indicators. Methods. DMFT, DMFS, dmft, dmfs, and CDI indexes were applied. Fluoride urinary excretion and fluoride concentrations in home water, table salt, bottled water, bottled drinks, and toothpaste were determined. Results. Schoolchildren presented fluorosis (CDI = 0.96 and dental caries (DMFT = 2.64 and DMFS = 3.97. Preschoolers presented dmft = 4.85 and dmfs = 8.80. DMFT and DMFS were lower in children with mild to moderate dental fluorosis (DF. Variable fluoride concentrations were found in the analyzed products (home water = 0.18–0.44 ppm F, table salt = 0–485 ppm F, bottled water = 0.18–0.47 ppm F, juices = 0.08–1.42 ppm F, nectars = 0.07–1.30 ppm F, bottled drinks = 0.10–1.70 ppm F, toothpaste = 0–2,053 ppm F. Mean daily fluoride excretion was 422 ± 176 µg/24 h for schoolchildren and 367 ± 150 µg/24 h for preschoolers. Conclusions. Data from our study show that, despite values of excretion within an optimal fluoride intake range, the prevalence of caries was significant in both groups, and 60% of the 11- to 12-year-old children presented with dental fluorosis. In addition, variable fluoride concentrations in products frequently consumed by children were found.

  12. Molten salt reactor concept

    International Nuclear Information System (INIS)

    Sood, D.D.

    1980-01-01

    Molten salt reactor is an advanced breeder concept which is suited for the utilization of thorium for nuclear power production. This reactor is based on the use of solutions of uranium or plutonium fluorides in LiF-BeF 2 -ThF 4 as fuel. Unlike the conventional reactors, no external coolant is used in the reactor core and the fuel salt itself is circulated through heat exchangers to transfer the fission produced heat to a secondary salt (NaF-NaBF 4 ) for steam generation. A part of the fuel stream is continuously processed to isolate 233 Pa, so that it can decay to fissile 233 U without getting converted to 234 Pa, and for the removal of neutron absorbing fission products. This on-line processing scheme makes this reactor concept to achieve a breeding ratio of 1.07 which is the highest for any thermal breeder reactor. Experimental studies at the Bhabha Atomic Research Centre, Bombay, have established the use of plutonium as fuel for this reactor. This molten salt reactor concept is described and the work conducted at the Bhabha Atomic Research Centre is summarised. (auth.)

  13. Industrial fluoride pollution: chronic fluoride poisoning in Cornwall Island cattle

    Energy Technology Data Exchange (ETDEWEB)

    Krook, L.; Maylin, G.A.

    1979-04-01

    An aluminum plant on the south bank of the St. Lawrence River, southwest of Cornwall Island, Ontario, Canada, has emitted 0.816 metric tons of fluoride daily since 1973. Considerably higher amounts were emitted from 1959 to 1973. The plant was designated as the major source of fluoride emissions impacting on Cornwall Island. Cattle located on this island showed signs of chronic fluoride poisoning. This poisoning was manifested clinically by stunted growth and dental fluorosis to a degree of severe interference with drinking and mastication. This Cornwall Island herds study indicates that the established tolerance level of fluoride for performance of dairy and beef cattle is not valid since the tolerance level was set based on experiments with healthy calves which were exposed to dietary fluoride from 3 to 4 months of age and not on cattle which were chronically exposed to fluoride from conception to death. 56 references.

  14. New Ru(II)N'NN'-type pincer complexes: synthesis, characterization and the catalytic hydrogenation of CO_2 or bicarbonates to formate salts

    International Nuclear Information System (INIS)

    Zengjin Dai; Qi Luo; Hengjiang Cong; Jing Zhang; Tianyou Peng

    2017-01-01

    [RuCl(L1)(MeCN)_2]Cl (1) and [RuCl(L2)(MeCN)_2]Cl (2) complexes were prepared through the reaction of [RuCl2(p-cymene)]_2 with 2,6-bis(benzimidazole-2-yl)-4-hydroxy-pyridine (L1) or 2,6-bis(benzimidazole- 2-yl) pyridine (L2) in acetonitrile, respectively. The treatment of [Ru(OTf)(L2)(MeCN)_2]OTf (3) with 1 equivalent of PPh_3 in ethanol resulted in the formation of [Ru(L2"-"1)(MeCN)(PPh_3)_2]OTf (4), in which one of the N-H moieties of L2 is deprotonated to give an anionic ligand (L2"-"1). It was found that complex 1 can catalyze the hydrogenation of CO_2 to formate salts, producing sodium formate in 34.0% yield with a turnover number (TON) of 407 under the optimized conditions. Further investigations revealed that complexes 1-4 can efficiently catalyze the hydrogenation of sodium bicarbonate to sodium formate, and the catalytic activity follows the order 4 ≥ 1 ≥ 2 ≅ 3. In particular, sodium formate was obtained in good yield (77%) with a high TON (1530) when complex 4 was used as the catalyst. The present results illustrate a new example of Ru(II) complexes bearing a rigid N'NN' framework for the efficient hydrogenation of CO_2 to formate salts in a homogeneous system. (authors)

  15. Molten salt reactors. Synthesis of studies realized between 1973 and 1983. General synthesis

    International Nuclear Information System (INIS)

    Hery, M.; Lecocq, A.

    1983-03-01

    After a brief recall of the MSBR project, French studies on molten salt reactors are summed up. Theoretical and experimental studies for a graphite moderated 1000 MWe reactor using molten Li, Be, Th and U fluorides cooled by salt-lead direct contact are given. These studies concern the core, molten salt chemistry, graphite, metals (molybdenum, alloy TZM), corrosion, reactor components [fr

  16. Fundamentals of molten-salt thermal technology

    International Nuclear Information System (INIS)

    1980-08-01

    This book has been published by the Society of Molten-Salt Thermal Technology to publish a part of the achievement of its members. This book is composed of seven chapters. The chapter 1 is Introduction. The chapter 2 explains the physical properties of molten salts, such as thermal behavior, surface tension, viscosity, electrical conductivity and others. The chapter 3 presents the compatibility with construction materials. Corrosion in molten salts, the electrochemical behavior of fluoride ions on carbon electrodes in fluoride melts, the behaviors of hastelloy N and metals in melts are items of this chapter. The equipments and instruments for molten salts are described in chapter 4. The heat transfer in molten salts is discussed in chapter 5. The chapter 6 explains the application of molten salt technology. The molten salt technology can be applied not only to thermal engineering and energy engineering but also to chemical and nuclear engineerings, and the technical fundamentals, current development status, technical problems and the perspective for the future are outlined. The chapter 7 is the summary of this book. The commercialization of molten salt power reactors is discussed at the end of this book. (Kato, T.)

  17. Monitoring of fluoride in water samples using a smartphone

    Energy Technology Data Exchange (ETDEWEB)

    Levin, Saurabh [Akvo Foundation (Netherlands); Krishnan, Sunderrajan [INREM Foundation (India); Rajkumar, Samuel; Halery, Nischal; Balkunde, Pradeep [Akvo Foundation (Netherlands)

    2016-05-01

    In several parts of India, groundwater is the only reliable, year round source for drinking water. Prevention of fluorosis, a chronic disease resulting from excess intake of fluoride, requires the screening of all groundwater sources for fluoride in endemic areas. In this paper, the authors present a field deployable colorimetric analyzer based on an inexpensive smartphone embedded with digital camera for taking photograph of the colored solution as well as an easy-fit, and compact sample chamber (Akvo Caddisfly). Phones marketed by different smartphone makers were used. Commercially available zirconium xylenol orange reagent was used for determining fluoride concentration. A software program was developed to use with the phone for recording and analyzing the RGB color of the picture. Linear range for fluoride estimation was 0–2 mg l{sup −1}. Around 200 samples, which consisted of laboratory prepared as well as field samples collected from different locations in Karnataka, India, were tested with Akvo Caddisfly. The results showed a significant positive correlation between Ion Selective Electrode (ISE) method and Akvo Caddisfly (Phones A, B and C), with correlation coefficient ranging between 0.9952 and 1.000. In addition, there was no significant difference in the mean fluoride content values between ISE and Phone B and C except for Phone A. Thus the smartphone method is economical and suited for groundwater fluoride analysis in the field. - Highlights: • Fluoride is an inorganic pollutant in ground water, affecting human health. • A colorimetric method for measurement of fluoride in drinking water with smartphone • Measurement is by mixing water with zirconyl xylenol orange complex reagent. • Results are comparable with laboratory-based ion selective fluoride electrode method.

  18. Monitoring of fluoride in water samples using a smartphone

    International Nuclear Information System (INIS)

    Levin, Saurabh; Krishnan, Sunderrajan; Rajkumar, Samuel; Halery, Nischal; Balkunde, Pradeep

    2016-01-01

    In several parts of India, groundwater is the only reliable, year round source for drinking water. Prevention of fluorosis, a chronic disease resulting from excess intake of fluoride, requires the screening of all groundwater sources for fluoride in endemic areas. In this paper, the authors present a field deployable colorimetric analyzer based on an inexpensive smartphone embedded with digital camera for taking photograph of the colored solution as well as an easy-fit, and compact sample chamber (Akvo Caddisfly). Phones marketed by different smartphone makers were used. Commercially available zirconium xylenol orange reagent was used for determining fluoride concentration. A software program was developed to use with the phone for recording and analyzing the RGB color of the picture. Linear range for fluoride estimation was 0–2 mg l"−"1. Around 200 samples, which consisted of laboratory prepared as well as field samples collected from different locations in Karnataka, India, were tested with Akvo Caddisfly. The results showed a significant positive correlation between Ion Selective Electrode (ISE) method and Akvo Caddisfly (Phones A, B and C), with correlation coefficient ranging between 0.9952 and 1.000. In addition, there was no significant difference in the mean fluoride content values between ISE and Phone B and C except for Phone A. Thus the smartphone method is economical and suited for groundwater fluoride analysis in the field. - Highlights: • Fluoride is an inorganic pollutant in ground water, affecting human health. • A colorimetric method for measurement of fluoride in drinking water with smartphone • Measurement is by mixing water with zirconyl xylenol orange complex reagent. • Results are comparable with laboratory-based ion selective fluoride electrode method.

  19. The importance of α-CT and Salt bridges in the Formation of Insulin and its Receptor Complex by Computational Simulation.

    Science.gov (United States)

    Dehghan-Shasaltaneh, Marzieh; Lanjanian, Hossein; Riazi, Gholam Hossein; Masoudi-Nejad, Ali

    2018-01-01

    Insulin hormone is an important part of the endocrine system. It contains two polypeptide chains and plays a pivotal role in regulating carbohydrate metabolism. Insulin receptors (IR) located on cell surface interacts with insulin to control the intake of glucose. Although several studies have tried to clarify the interaction between insulin and its receptor, the mechanism of this interaction remains elusive because of the receptor's structural complexity and structural changes during the interaction. In this work, we tried to fractionate the interactions. Therefore, sequential docking method utilization of HADDOCK was used to achieve the mentioned goal, so the following processes were done: the first, two pdb files of IR i.e., 3LOH and 3W11 were concatenated using modeller. The second, flexible regions of IR were predicted by HingeProt. Output files resulting from HingeProt were uploaded into HADDOCK. Our results predict new salt bridges in the complex and emphasize on the role of salt bridges to maintain an inverted V structure of IR. Having an inverted V structure leads to activate intracellular signaling pathway. In addition to presence salt bridges to form a convenient structure of IR, the importance of α-chain of carboxyl terminal (α-CT) to interact with insulin was surveyed and also foretokened new insulin/IR contacts, particularly at site 2 (rigid parts 2 and 3). Finally, several conformational changes in residues Asn711-Val715 of α-CT were occurred, we suggest that α-CT is a suitable situation relative to insulin due to these conformational alterations.

  20. Method for routine determination of fluoride in urine by selective ion- electrode

    International Nuclear Information System (INIS)

    Pires, M.A.F.; Bellintani, S.A.

    1985-01-01

    A simple, fast and sensitive method is outlined for determining fluoride in urine of workers who handle fluoride compounds. The determination is based on the measurement of fluoride by ion selective electrode. Cationic interferents like Ca ++ , Mg ++ , Fe +++ and Al +++ are complexed by EDTA and citric acid. Common anions present in urine, such as Cl - , PO --- 4 and SO -- 4 do not interfere in the method. (Author) [pt

  1. Enhancement of natural radioactivity in soils and salt-marshes surrounding a non-nuclear industrial complex

    International Nuclear Information System (INIS)

    Bologon, J.P.; Garca-Tenorio, R.; Garca-Leon, M.

    1995-01-01

    The existence of a very high extension (about 1000 ha) of phosphogypsum piles, sited in the estuary formed by the mouths of the Tinto and Odiel rivers (SW Spain), produce a quite local, but unambiguous radioactive impact in the surrounding salt-marshes. In these piles the main by-product formed in the manufacture of phosphoric acid is stored. The radioactive impact is generated by the deposition and accumulation of radionuclides from the uranium series that previously had been mainly leached or dissolved from the piles by waters that temporally can cover or cross them. Other means of impact, especially through the atmosphere, have been evaluated as negligible or not detectable

  2. Fluoride ion recognition by chelating and cationic boranes.

    Science.gov (United States)

    Hudnall, Todd W; Chiu, Ching-Wen; Gabbaï, François P

    2009-02-17

    Because of the ubiquity of fluoride ions and their potential toxicity at high doses, researchers would like to design receptors that selectively detect this anion. Fluoride is found in drinking water, toothpaste, and osteoporosis drugs. In addition, fluoride ions also can be detected as an indicator of uranium enrichment (via hydrolysis of UF(6)) or of the chemical warfare agent sarin, which releases the ion upon hydrolysis. However, because of its high hydration enthalpy, the fluoride anion is one of the most challenging targets for anion recognition. Among the various recognition strategies that are available, researchers have focused a great deal of attention on Lewis acidic boron compounds. These molecules typically interact with fluoride anions to form the corresponding fluoroborate species. In the case of simple triarylboranes, the fluoroborates are formed in organic solvents but not in water. To overcome this limitation, this Account examines various methods we have pursued to increase the fluoride-binding properties of boron-based receptors. We first considered the use of bifunctional boranes, which chelate the fluoride anion, such as 1,8-diborylnaphthalenes or heteronuclear 1-boryl-8-mercurio-naphthalenes. In these molecules, the neighboring Lewis acidic atoms can cooperatively interact with the anionic guest. Although the fluoride binding constants of the bifunctional compounds exceed those of neutral monofunctional boranes by several orders of magnitude, the incompatibility of these systems with aqueous media limits their utility. More recently, we have examined simple triarylboranes whose ligands are decorated by cationic ammonium or phosphonium groups. These cationic groups increase the electrophilic character of these boranes, and unlike their neutral analogs, they are able to complex fluoride in aqueous media. We have also considered cationic boranes, which form chelate complexes with fluoride anions. Our work demonstrates that Coulombic and chelate

  3. Physiology and toxicity of fluoride

    Directory of Open Access Journals (Sweden)

    Dhar Vineet

    2009-01-01

    Full Text Available Fluoride has been described as an essential element needed for normal development and growth of animals and extremely useful for human beings. Fluoride is abundant in the environment and the main source of fluoride to humans is drinking water. It has been proved to be beneficial in recommended doses, and at the same time its toxicity at higher levels has also been well established. Fluoride gets accumulated in hard tissues of the body and has been know to play an important role in mineralization of bone and teeth. At high levels it has been known to cause dental and skeletal fluorosis. There are suggested effects of very high levels of fluoride on various body organs and genetic material. The purpose of this paper is to review the various aspects of fluoride and its importance in human life.

  4. Physiology and toxicity of fluoride.

    Science.gov (United States)

    Dhar, Vineet; Bhatnagar, Maheep

    2009-01-01

    Fluoride has been described as an essential element needed for normal development and growth of animals and extremely useful for human beings. Fluoride is abundant in the environment and the main source of fluoride to humans is drinking water. It has been proved to be beneficial in recommended doses, and at the same time its toxicity at higher levels has also been well established. Fluoride gets accumulated in hard tissues of the body and has been know to play an important role in mineralization of bone and teeth. At high levels it has been known to cause dental and skeletal fluorosis. There are suggested effects of very high levels of fluoride on various body organs and genetic material. The purpose of this paper is to review the various aspects of fluoride and its importance in human life.

  5. Moltex Energy's stable salt reactors

    International Nuclear Information System (INIS)

    O'Sullivan, R.; Laurie, J.

    2016-01-01

    A stable salt reactor is a molten salt reactor in which the molten fuel salt is contained in fuel rods. This concept was invented in 1951 and re-discovered and improved recently by Moltex Energy Company. The main advantage of using molten salt fuel is that the 2 problematic fission products cesium and iodine do not exist in gaseous form but rather in a form of a salt that present no danger in case of accident. Another advantage is the strongly negative temperature coefficient for reactivity which means the reactor self-regulates. The feasibility studies have been performed on a molten salt fuel composed of sodium chloride and plutonium/uranium/lanthanide/actinide trichloride. The coolant fluid is a mix of sodium and zirconium fluoride salts that will need low flow rates. The addition of 1 mol% of metal zirconium to the coolant fluid reduces the risk of corrosion with standard steels and the addition of 2% of hafnium reduces the neutron dose. The temperature of the coolant is expected to reach 650 Celsius degrees at the exit of the core. This reactor is designed to be modular and it will be able to burn actinides. (A.C.)

  6. Magnesium fluoride recovery method

    International Nuclear Information System (INIS)

    Gay, R.L.; McKenzie, D.E.

    1989-01-01

    A method of obtaining magnesium fluoride substantially free from radioactive uranium from a slag formed in the production of metallic uranium by the reduction of depleted uranium tetrafluoride with metallic magnesium in a retort wherein the slag contains the free metals magnesium and uranium and also oxides and fluorides of the metals. The slag having a radioactivity level of at least about 7,000 rhoCi/gm. The method comprises the steps of: grinding the slag to a median particle size of about 200 microns; contacting the ground slag in a reaction zone with an acid having a strength of from about 0.5 to 1.5 N for a time of from about 4 to about 20 hours in the presence of a catalytic amount of iron; removing the liquid product; treating the particulate solid product; repeating the last two steps at least one more time to produce a solid residue consisting essentially of magnesium fluoride substantially free of uranium and having a residual radioactivity level of less than about 1000 rhoCi/gm

  7. Study on the removal of fluoride from drinking water and effluents

    International Nuclear Information System (INIS)

    Charbel, M.Y.

    1990-01-01

    A study for removal of excess fluoride from drinking water and aqueous effluents from nuclear power plants is presented. Inorganic and organic ion exchangers were used for this purpose: 1. Alumina microspheres form, granular alumina and zirconium oxide (powder or granular form with the aid of agglutinants) were experimented. 2. Strong cation exchange resins as Al-III, Fe-III, Zr-IV, RE-III, Ca-II and Mg-II salt form were examined. 3. Retention on hydrous oxide of Al-III, Fe-III, Zr-IV and RE-III supported on strong cation ion exchanger was performed. 4. Strong anion exchange resins in the form of OH sup(-), Cl sup(-), NO3 sup(-), CO3 sup(2-), SO4 sup(2-), ClO4 sup(-) and Zr(SO4)3 sup(2-) were examined. For the experiments pure fluoride solutions or dilute solutions containing the cations of Fe-III, Ca-II, Mn-II, Cu-II, Al-III, Cd-II and U-VI were used. Cation exchange resin loaded with zirconium, anion exchange resin as hydroxyl and zirconium sulfate complex form exhibited very good results, but the last performed best and we suggest it for industrial application. (author)

  8. Physiology and toxicity of fluoride

    OpenAIRE

    Dhar Vineet; Bhatnagar Maheep

    2009-01-01

    Fluoride has been described as an essential element needed for normal development and growth of animals and extremely useful for human beings. Fluoride is abundant in the environment and the main source of fluoride to humans is drinking water. It has been proved to be beneficial in recommended doses, and at the same time its toxicity at higher levels has also been well established. Fluoride gets accumulated in hard tissues of the body and has been know to play an important role in mineralizat...

  9. Inertia-confining thermonuclear molten salt reactors

    International Nuclear Information System (INIS)

    Furukawa, Kazuo; Yamanaka, Chiyoe; Nakai, Sadao; Imon, Shunji; Nakajima, Hidenori; Nakamura, Norio; Kato, Yoshio.

    1984-01-01

    Purpose: To increase the heat generating efficiency while improving the reactor safety and thereby maintaining the energy balance throughout the reactor. Constitution: In an inertia-confining type D-T thermonuclear reactor, the blanket is made of lithium-containing fluoride molten salts (LiF.BeF 2 , LiF.NaF.KF, LiF.KF, etc) which are cascaded downwardly in a large thickness (50 - 100 cm) along the inner wall of the thermonuclear reaction vessel, and neutrons generated by explosive compression are absorbed to lithium in the molten salts to produce tritium, Heat transportation is carried out by the molten salts. (Ikeda, J.)

  10. Nutritional and water effect on fluoride uptake and respiration of bean seedlings. [Phaseolus vulgaris

    Energy Technology Data Exchange (ETDEWEB)

    Applegate, H G; Adams, D F

    1960-01-01

    Bean plants (Phaseolus vulgaris) were grown in an atmosphere containing 2.0 +/- 0.21 g F /mT (1.6 ppb). The effect of N, P, K, Fe, and Ca deficiencies and the effect of osmotic pressures of 0, 1.5, 3.0, 4.5, 6.0 and 7.5 pounds on fluoride uptake and fluoride-mediated respiration were studied. The data showed that P deficient plants took up more fluoride than plants deficient in any of the other elements studied. Fluoride-mediated respiration was phosphorous dependent, however. Plants low in Fe or K showed increased uptake of fluoride. Nitrogen had no effect on fluoride uptake under the conditions of this experiment. Plants low in Fe showed inhibition of oxygen uptake. This inhibition was accentuated by fluoride. The interactions of N, K and Ca with fluoride on respiration were complex. Neither fluoride uptake nor fluoride-mediated respiration appeared to be linked directly to the water economy of the plants. 14 references, 6 tables.

  11. The molten salt reactor adventure

    International Nuclear Information System (INIS)

    MacPherson, H.G.

    1985-01-01

    A personal history of the development of molten salt reactors in the United States is presented. The initial goal was an aircraft propulsion reactor, and a molten fluoride-fueled Aircraft Reactor Experiment was operated at Oak Ridge National Laboratory in 1954. In 1956, the objective shifted to civilian nuclear power, and reactor concepts were developed using a circulating UF 4 -ThF 4 fuel, graphite moderator, and Hastelloy N pressure boundary. The program culminated in the successful operation of the Molten Salt Reactor Experiment in 1965 to 1969. By then the Atomic Energy Commission's goals had shifted to breeder development; the molten salt program supported on-site reprocessing development and study of various reactor arrangements that had potential to breed. Some commercial and foreign interest contributed to the program which, however, was terminated by the government in 1976. The current status of the technology and prospects for revived interest are summarized

  12. System Requirements Document for the Molten Salt Reactor Experiment 233U conversion system

    International Nuclear Information System (INIS)

    Aigner, R.D.

    2000-01-01

    The purpose of the conversion process is to convert the 233 U fluoride compounds that are being extracted from the Molten Salt Reactor Experiment (MSRE) equipment to a stable oxide for long-term storage at Bldg. 3019

  13. Use of water in aiding olefin/paraffin (liquid + liquid) extraction via complexation with a silver bis(trifluoromethylsulfonyl)imide salt

    International Nuclear Information System (INIS)

    Wang, Yu; Thompson, Jillian; Zhou, Jingjing; Goodrich, Peter; Atilhan, Mert; Pensado, Alfonso S.; Kirchner, Barbara; Rooney, David; Jacquemin, Johan; Khraisheh, Majeda

    2014-01-01

    Highlights: • Silver-based ILs used as olefin extracting agents for olefin/paraffin mixtures. • Each extraction process is based on the olefin complexation and solvation. • The presence of water influences positively each extraction process. • Each extraction process was evaluated by DFT calculations, NMR, IR and Raman. • LLE data were then correlated by using the UNIQUAC model. - Abstract: This paper describes the extraction of C 5 –C 8 linear α-olefins from olefin/paraffin mixtures of the same carbon number via a reversible complexation with a silver salt (silver bis(trifluoromethylsulfonyl)imide, Ag[Tf 2 N]) to form room temperature ionic liquids [Ag(olefin) x ][Tf 2 N]. From the experimental (liquid + liquid) equilibrium data for the olefin/paraffin mixtures and Ag[Tf 2 N], 1-pentene showed the best separation performance while C 7 and C 8 olefins could only be separated from the corresponding mixtures on addition of water which also improves the selectivity at lower carbon numbers like the C 5 and C 6 , for example. Using infrared and Raman spectroscopy of the complex and Ag[Tf 2 N] saturated by olefin, the mechanism of the extraction was found to be based on both chemical complexation and the physical solubility of the olefin in the ionic liquid ([Ag(olefin) x ][Tf 2 N]). These experiments further support the use of such extraction techniques for the separation of olefins from paraffins

  14. Molecular mechanisms of fluoride toxicity.

    Science.gov (United States)

    Barbier, Olivier; Arreola-Mendoza, Laura; Del Razo, Luz María

    2010-11-05

    Halfway through the twentieth century, fluoride piqued the interest of toxicologists due to its deleterious effects at high concentrations in human populations suffering from fluorosis and in in vivo experimental models. Until the 1990s, the toxicity of fluoride was largely ignored due to its "good reputation" for preventing caries via topical application and in dental toothpastes. However, in the last decade, interest in its undesirable effects has resurfaced due to the awareness that this element interacts with cellular systems even at low doses. In recent years, several investigations demonstrated that fluoride can induce oxidative stress and modulate intracellular redox homeostasis, lipid peroxidation and protein carbonyl content, as well as alter gene expression and cause apoptosis. Genes modulated by fluoride include those related to the stress response, metabolic enzymes, the cell cycle, cell-cell communications and signal transduction. The primary purpose of this review is to examine recent findings from our group and others that focus on the molecular mechanisms of the action of inorganic fluoride in several cellular processes with respect to potential physiological and toxicological implications. This review presents an overview of the current research on the molecular aspects of fluoride exposure with emphasis on biological targets and their possible mechanisms of involvement in fluoride cytotoxicity. The goal of this review is to enhance understanding of the mechanisms by which fluoride affects cells, with an emphasis on tissue-specific events in humans. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  15. Method for fluoride routine determination in urine of personnel exposed, by ion selective electrode

    International Nuclear Information System (INIS)

    Pires, M.A.F.; Bellintani, S.A.

    1986-01-01

    A simple, fast and sensible method is outlined for the determination of fluoride in urine of workers that handle fluorine compounds. The determination is based on the measurement of fluoride by ion selective electrode. Cationic interference like Ca ++ , Mg ++ , Fe +++ and Al +++ are complexed by EDTA and citric acid. (Author) [pt

  16. Preparation of sodium fluoride agglomerates for selective adsorption of uranium hexafluoride (U F6)

    International Nuclear Information System (INIS)

    Castro, A.R.; Maximiano, C.; Shimba, R.; Silva, E.R.F.

    1995-01-01

    Uranium hexafluoride (U F 6 ) and Sodium Fluoride (NaF) reacts reversibly to form a solid complex. Such reversibility accounts for the great interest in using Sodium Fluoride (NaF) to separate Uranium Hexafluoride (U F 6 ) from other gases. Therefore a chemical trap offers an alternative to the cryogenic trapping device. (author). 3 refs, 1 fig, 4 tabs

  17. Radio elements / bottom salts separation by nano-filtration aided by complexation in a highly saline environment

    International Nuclear Information System (INIS)

    Gaubert, Eric

    1997-01-01

    This research thesis addresses the use of a membrane-based technique, nano-filtration, aided or not by complexation, for the processing of highly saline liquid effluents produced by radio-chemical decontamination. The objective is to separate non-radioactive elements (sodium nitrate) from radio-elements (caesium, strontium and actinides) in order to reduce the volume of wastes. Within the perspective of an industrial application, a system to concentrate the effluent is firstly defined. Different nano-filtration membranes are tested and reveal to be insufficient in highly saline environment. A stage of selective complexation of radio-elements is therefore considered before nano-filtration. The main factors affecting performance of nano-filtration-complexation (for a given membrane system) are identified: ionic force, pH, ligand content, trans-membrane pressure. Finally, a nano-filtration pilot is implemented to perform nano-filtration-complexation operations by remote handling on radioactive substances [fr

  18. New primary energy source by thorium molten-salt reactor technology

    International Nuclear Information System (INIS)

    Furukawa, Kazuo; Kato, Yoshio; Furuhashi, Akira; Numata, Hiroo; Mitachi, Koushi; Yoshioka, Ritsuo; Sato, Yuzuru; Arakawa, Kazuto

    2005-01-01

    Among the next 30 years, we have to implement a practical measure in the global energy/environmental problems, solving the followings: (1) replacing the fossil fuels without CO 2 emission, (2) no severe accidents, (3) no concern on military, (4) minimizing wastes, (5) economical, (6) few R and D investment and (7) rapid/huge global application supplying about half of the total primary energy till 50 years later. For this purpose the following system was proposed: THORIMS-NES [Thorium Molten-Salt Nuclear Energy Synergetic System], which is composed of (A) simple fission Molten-Salt power stations (FUJI), and (B) fissile-producing Accelerator Molten-Salt Breeder (AMSB). It has been internationally prepared a practical Developmental Program for its huge-size industrialization of Th breeding fuel cycle to produce a new rational primary energy. Here it is explained the social meaning, the conceptual system design and technological bases, especially, including the molten fluoride salt technology, which was developed as the triple-functional medium for nuclear-engineering, heat-transfer and chemical engineering. The complex function of this system is fully achieved by the simplified facility using a single phase molten-salt only. (author)

  19. Comparative analysis of Pu spread resistance of chemico-technological (out of pile) complexes of electronuclear molten salt and heavy water blanket facilities for transmutation

    International Nuclear Information System (INIS)

    Volk, V.I.; Vakhrushin, A.Yu.; Gorbunov, V.F.; Kushnikov, V.V.

    1997-01-01

    Technological processes used for radiochemical reprocessing of molten salt and heavy water blankets of an electronuclear facility for Pu transmutation and Pu distribution in those processes are characterized. Below the major parameters are given that affect the resistance of the technological to Pu proliferation. Types of Pu migration: process losses, accident related losses, theft. Factors affecting migration are total inventory of Pu in a reprocessing complex, purity of Pu and its compounds, chemical condition of Pu, the feasibility of equipping technological processes with instruments of control. The comparative analysis carried out taking into account the above parameters established that the technological processes related to heavy water blanket reprocessing, specifically a homogeneous (solution) option, are much more resistant to Pu proliferation, including both Pu migration to the environment and the unsanctioned withdrawal of Pu from the technological process. 5 refs., 4 figs

  20. Liquid-liquid extraction of ion-association complexes of cobalt(II-4-(2-pyridylazoresorcinol with ditetrazolium salts

    Directory of Open Access Journals (Sweden)

    Divarova Vidka V.

    2015-01-01

    Full Text Available The formation and liquid-liquid extraction of ion-association complexes between Co(II-4-(2-Pyridylazoresorcinol (PAR anionic chelates and cations of three ditetrazolium chlorides were studied: Blue Tetrazolium chloride (BTC, Neotetrazolium chloride (NTC and Nitro Blue Tetrazolium chloride (NBT. The optimum conditions for the formation and solvent extraction of the ion-association comlpex chelates were determined. It has been found that in the systems of Co(II-PAR-DTS, the reactants are reacted in molar ratios 1:2:1 and the general formula of complexes was suggested. The extraction equilibria were investigated and quantitatively characterized by the equilibrium constants and the recovery factors. The analytical characteristics of the complexes were calculated.

  1. 49 CFR 173.163 - Hydrogen fluoride.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Hydrogen fluoride. 173.163 Section 173.163... Hydrogen fluoride. (a) Hydrogen fluoride (hydrofluoric acid, anhydrous) must be packaged as follows: (1) In... filling ratio of 0.84. (b) A cylinder removed from hydrogen fluoride service must be condemned in...

  2. Growth of fluoride treated Kalanchoe pinnata plants

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, H N; Applegate, H G

    1962-01-01

    Kalanchoe pinnata plants can absorb fluoride through roots. The absorption is related to the amount of fluoride applied to the soil. There appeared to be a relationship between the amount of fluoride adsorbed and the subsequent growth of the plants. Plants which adsorbed the largest amounts of fluoride had the greatest increase in growth.

  3. Advantages of liquid fluoride thorium reactor in comparison with light water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Bahri, Che Nor Aniza Che Zainul, E-mail: anizazainul@gmail.com; Majid, Amran Ab.; Al-Areqi, Wadeeah M. [Nuclear Science Program, School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia)

    2015-04-29

    Liquid Fluoride Thorium Reactor (LFTR) is an innovative design for the thermal breeder reactor that has important potential benefits over the traditional reactor design. LFTR is fluoride based liquid fuel, that use the thorium dissolved in salt mixture of lithium fluoride and beryllium fluoride. Therefore, LFTR technology is fundamentally different from the solid fuel technology currently in use. Although the traditional nuclear reactor technology has been proven, it has perceptual problems with safety and nuclear waste products. The aim of this paper is to discuss the potential advantages of LFTR in three aspects such as safety, fuel efficiency and nuclear waste as an alternative energy generator in the future. Comparisons between LFTR and Light Water Reactor (LWR), on general principles of fuel cycle, resource availability, radiotoxicity and nuclear weapon proliferation shall be elaborated.

  4. Comparison of the toxicity of fluoridation compounds in the nematode Caenorhabditis elegans.

    Science.gov (United States)

    Rice, Julie R; Boyd, Windy A; Chandra, Dave; Smith, Marjolein V; Den Besten, Pamela K; Freedman, Jonathan H

    2014-01-01

    Fluorides are commonly added to drinking water in the United States to decrease the incidence of dental caries. Silicofluorides, such as sodium hexafluorosilicate (Na2 SiF6 ) and fluorosilicic acid (H2 SiF6 ), are mainly used for fluoridation, although fluoride salts such as sodium fluoride (NaF) are also used. Interestingly, only the toxicity of NaF has been examined and not that of the more often used silicofluorides. In the present study, the toxicities of NaF, Na2 SiF6 , and H2 SiF6 were compared. The toxicity of these fluorides on the growth, feeding, and reproduction in the alternative toxicological testing organism Caenorhabditis elegans was examined. Exposure to these compounds produced classic concentration-response toxicity profiles. Although the effects of the fluoride compounds varied among the 3 biological endpoints, no differences were found between the 3 compounds, relative to the fluoride ion concentration, in any of the assays. This suggests that silicofluorides have similar toxicity to NaF. © 2013 SETAC.

  5. Hemoglobin and Myoglobin as Reducing Agents in Biological Systems. Redox Reactions of Globins with Copper and Iron Salts and Complexes.

    Science.gov (United States)

    Postnikova, G B; Shekhovtsova, E A

    2016-12-01

    In addition to reversible O2 binding, respiratory proteins of the globin family, hemoglobin (Hb) and myoglobin (Mb), participate in redox reactions with various metal complexes, including biologically significant ones, such as those of copper and iron. HbO 2 and MbO 2 are present in cells in large amounts and, as redox agents, can contribute to maintaining cell redox state and resisting oxidative stress. Divalent copper complexes with high redox potentials (E 0 , 200-600 mV) and high stability constants, such as [Cu(phen) 2 ] 2+ , [Cu(dmphen) 2 ] 2+ , and CuDTA oxidize ferrous heme proteins by the simple outer-sphere electron transfer mechanism through overlapping π-orbitals of the heme and the copper complex. Weaker oxidants, such as Cu2+, CuEDTA, CuNTA, CuCit, CuATP, and CuHis (E 0 ≤ 100-150 mV) react with HbO 2 and MbO 2 through preliminary binding to the protein with substitution of the metal ligands with protein groups and subsequent intramolecular electron transfer in the complex (the site-specific outer-sphere electron transfer mechanism). Oxidation of HbO 2 and MbO 2 by potassium ferricyanide and Fe(3) complexes with NTA, EDTA, CDTA, ATP, 2,3-DPG, citrate, and pyrophosphate PP i proceeds mainly through the simple outer-sphere electron transfer mechanism via the exposed heme edge. According to Marcus theory, the rate of this reaction correlates with the difference in redox potentials of the reagents and their self-exchange rates. For charged reagents, the reaction may be preceded by their nonspecific binding to the protein due to electrostatic interactions. The reactions of LbO 2 with carboxylate Fe complexes, unlike its reactions with ferricyanide, occur via the site-specific outer-sphere electron transfer mechanism, even though the same reagents oxidize structurally similar MbO 2 and cytochrome b 5 via the simple outer-sphere electron transfer mechanism. Of particular biological interest is HbO 2 and MbO 2 transformation into met-forms in the presence

  6. FLUORIDE TOXICITY – A HARSH REALITY

    OpenAIRE

    Bandlapalli Pavani; Mandava Ragini; David Banji; Otilia J F Banji; N Gouri Pratusha

    2011-01-01

    There are many incidents of fluoride toxicity whether it is acute or chronic. Fluoride toxicity is an environmental hazard which arises from the upper layers of geological crust and is dissolved in water. Prolonged drinking of such water causes chronic fluoride toxicity. Use of fluoride containing compounds for various purposes such as dental products, metal, glass, refrigerator and chemical industries act as a source of fluoride poisoning and increase the risk of toxicity. This review reflec...

  7. Strontium-90 fluoride data sheet

    Energy Technology Data Exchange (ETDEWEB)

    Fullam, H.T.

    1981-06-01

    This report is a compilation of available data and appropriate literature references on the properties of strontium-90 fluoride and nonradioactive strontium fluoride. The objective of the document is to compile in a single source pertinent data to assist potential users in the development, licensing, and use of /sup 90/SrF/sub 2/-fueled radioisotope heat sources for terrestrial power conversion and thermal applications. The report is an update of the Strontium-90 Fluoride Data Sheet (BNWL-2284) originally issued in April 1977.

  8. Salt Tolerance

    OpenAIRE

    Xiong, Liming; Zhu, Jian-Kang

    2002-01-01

    Studying salt stress is an important means to the understanding of plant ion homeostasis and osmo-balance. Salt stress research also benefits agriculture because soil salinity significantly limits plant productivity on agricultural lands. Decades of physiological and molecular studies have generated a large body of literature regarding potential salt tolerance determinants. Recent advances in applying molecular genetic analysis and genomics tools in the model plant Arabidopsis thaliana are sh...

  9. Sea salt

    OpenAIRE

    Galvis-Sánchez, Andrea C.; Lopes, João Almeida; Delgadillo, Ivone; Rangel, António O. S. S.

    2013-01-01

    The geographical indication (GI) status links a product with the territory and with the biodiversity involved. Besides, the specific knowledge and cultural practices of a human group that permit transforming a resource into a useful good is protected under a GI designation. Traditional sea salt is a hand-harvested product originating exclusively from salt marshes from specific geographical regions. Once salt is harvested, no washing, artificial drying or addition of anti-caking agents are all...

  10. Matrix supported tailored polymer for solid phase extraction of fluoride from variety of aqueous streams

    International Nuclear Information System (INIS)

    Thakur, Neha; Kumar, Sanjukta A.; Wagh, D.N.; Das, Sadananda; Pandey, Ashok K.; Kumar, Sangita D.; Reddy, A.V.R.

    2012-01-01

    Highlights: ► Th complexed with poly (bis[2-(methacryloyloxy)-ethyl]phosphate) as tailored polymer membranes. ► Membranes offered high capacity and selectivity for fluoride in aqueous media. ► Quantitative uptake (80 ± 5%) of fluoride. ► Fast sorption kinetics. ► Reusability of polymer membranes. - Abstract: Fluoride related health hazards (fluorosis) are a major environmental problem in many regions of the world. It affects teeth; skeleton and its accumulation over a long period can lead to changes in the DNA structure. It is thus absolutely essential to bring down the fluoride levels to acceptable limits. Here, we present a new inorganic–organic hybrid polymer sorbent having tailored fixed-sites for fluoride sorption. The matrix supported poly (bis[2-(methacryloyloxy)-ethyl]phosphate) was prepared by photo-initiator induced graft-polymerization in fibrous and microporous (sheet) host poly(propylene) substrates. These substrates were conditioned for selective fluoride sorption by forming thorium complex with phosphate groups on bis[2-methacryloyloxy)-ethyl] phosphate (MEP). These tailored sorbents were studied for their selectivity towards fluoride in aqueous media having different chemical conditions. The fibrous sorbent was found to take up fluoride with a faster rate (15 min for ≈76% sorption) than the sheet sorbent. But, the fluoride loading capacity of sheet sorbent (4320 mg kg −1 ), was higher than fibrous and any other sorbent reported in the literature so far. The sorbent developed in the present work was found to be reusable after desorption of fluoride using NaOH solution. It was tested for solid phase extraction of fluoride from natural water samples.

  11. Studies on components for a molten salt reactor

    International Nuclear Information System (INIS)

    Nejedly, M.; Matal, O.

    2003-01-01

    The aim is contribute to a design of selected components of molten salt reactors with fuel in the molten fluoride salt matrix. Molten salt reactors (MSRs) permit the utilization of plutonium and minor actinides as new nuclear fuel from a traditional nuclear power station with production of electric energy. Results of preliminary feasibility studies of an intermediate heat exchanger, a small power molten salt pump and a modular conception of a steam generator for a demonstration unit of the MSR (30 MW) are summarized. (author)

  12. Evaluation of quality of permanent teeth restorations in children of areas contaminated by heavy metal salts

    Directory of Open Access Journals (Sweden)

    V. V. Avakov

    2014-04-01

    Full Text Available The influence of the environment on the child health is one of priority issues of the present time and it is of great social importance. Increased dental diseases associated with climatic and geographical characteristics of the area are widely discussed in the literature. The leading among them are environmentally determined dental diseases in children associated with geochemical and technogenic pollution of the area where they live. Increasing amounts of hard metal salts is the urgent hygienic problem, due to severity of their multi-element analysis in microsubjects, and negative influence on health of the children population, due to tropism, ability to cumulation, long biological life in the body and antagonism of heavy metal salts to the number of microelements. Influence of hard metal salts on dental diseases development is undeniable. Particular attention is paid to their influence on caries process and treatment peculiarities. Despite the fact that modern аdhesive dentistry in recent years has made a significant breakthrough in improving adhesive systems, correct choice of adhesive system depending on changes in the structure of hard tissue under geochemical contaminants (like heavy metal salts is the most important step. It is the decisive factor for adaptation and connection of restoration with the restoration base. We should remember that on the way of adhesive system there is an altered structure preventing from deep penetration of such system and, consequently, leading to violation of restoration tightness. Therefore, early detection of complications by clinical evaluation of quality of the restorations is of great interest. Multi-vector approach to treatment of dental caries in children living in conditions of technogenic pollution by heavy metal salts is extremely urgent and important issue. Significant niche in this approach is given to adhesive preparation methods combined with local fluoridation, using fluoride medication of the

  13. Fuel processing for molten-salt reactors

    International Nuclear Information System (INIS)

    Hightower, J.R. Jr.

    1976-01-01

    Research devoted to development of processes for the isolation of protactinium and for the removal of fission products from molten-salt breeder reactors is reported. During this report period, engineering development progressed on continuous fluorinators for uranium removal, the metal transfer process for rare-earth removal, the fuel reconstitution step, and molten salt--bismuth contactors to be used in reductive extraction processes. The metal transfer experiment MTE-3B was started. In this experiment all parts of the metal transfer process for rare-earth removal are demonstrated using salt flow rates which are about 1 percent of those required to process the fuel salt in a 1000-MW(e) MSBR. During this report period the salt and bismuth phases were transferred to the experimental vessels, and two runs with agitator speeds of 5 rps were made to measure the rate of transfer of neodymium from the fluoride salt to the Bi--Li stripper solution. The uranium removed from the fuel salt by fluorination must be returned to the processed salt in the fuel reconstitution step before the fuel salt is returned to the reactor. An engineering experiment to demonstrate the fuel reconstitution step is being installed. In this experiment gold-lined equipment will be used to avoid introducing products of corrosion by UF 6 and UF 5 . Alternative methods for providing the gold lining include electroplating and mechanical fabrication

  14. Beryllium production using beryllium fluoride

    International Nuclear Information System (INIS)

    Hubler, Carlos Henrique

    1993-01-01

    This work presents the beryllium production by thermal decomposition of the ammonium beryllium fluoride, followed by magnesium reduction, obtained in the small pilot plant of the Brazilian National Nuclear Energy Commission - Nuclear Engineering Institute

  15. Chronic Fluoride Toxicity: Dental Fluorosis

    OpenAIRE

    DenBesten, Pamela; Li, Wu

    2011-01-01

    Dental fluorosis occurs as a result of excess fluoride ingestion during tooth formation. Enamel fluorosis and primary dentin fluorosis can only occur when teeth are forming, and therefore fluoride exposure (as it relates to dental fluorosis) occurs during childhood. In the permanent dentition, this would begin with the lower incisors, which complete mineralization at approximately 2–3 years of age, and end after mineralization of the third molars. The white opaque appearance of fluorosed enam...

  16. Structural investigation of molten fluorides of nuclear interest by NMR and XAFS spectroscopies

    International Nuclear Information System (INIS)

    Pauvert, Olivier

    2009-01-01

    In the frame of the renewal of the different nuclear plans, the molten salt reactor is one of the six concepts of reactors of 4. generation. This reactor has the particularity to use a liquid fuel based on LiF-ThF 4 mixtures. In order to develop and to optimize this concept, it is important to characterize the structure of the melt and to describe its physical and chemical properties. Our work has been based on the study of the system MF-ZrF 4 (M = Li, Na, K) selected as a model of ThF 4 based systems. We have combined two spectroscopic techniques, the Nuclear Magnetic Resonance and the X-ray Absorption at high temperature, with molecular dynamics calculations. We particularly focused on the local environments of the fluorine and the zirconium. In order to interpret the NMR data obtain in the molten state, we performed a preliminary study on zirconium halides and rare earth and alkali fluoro zirconates using the 91 Zr solid-state NMR at very high magnetic fields. New correlations between structural parameters and NMR data have been established. At high temperature, in MF-ZrF 4 melts we have shown the coexistence of three different kind of Zr-based complexes with different proportions depending on the amount of ZrF 4 and on the nature of the alkali. Depending on the ZrF 4 content, three kinds of fluorine have been characterized: form free fluorines at low amount of zirconium fluorides, fluorines involved in Zr-based complexes and bridging fluorines at higher ZrF 4 content. This original and innovative approach of molten fluorides mixtures, combining NMR and EXAFS at high temperature with molecular dynamics calculations, is very efficient to describe their speciation and thus their fluoro-acidity. (author)

  17. Fluoride in groundwater: toxicological exposure and remedies.

    Science.gov (United States)

    Jha, S K; Singh, R K; Damodaran, T; Mishra, V K; Sharma, D K; Rai, Deepak

    2013-01-01

    Fluoride is a chemical element that is found most frequently in groundwater and has become one of the most important toxicological environmental hazards globally. The occurrence of fluoride in groundwater is due to weathering and leaching of fluoride-bearing minerals from rocks and sediments. Fluoride when ingested in small quantities (dental health by reducing dental caries, whereas higher concentrations (>1.5 mg/L) may cause fluorosis. It is estimated that about 200 million people, from among 25 nations the world over, may suffer from fluorosis and the causes have been ascribed to fluoride contamination in groundwater including India. High fluoride occurrence in groundwaters is expected from sodium bicarbonate-type water, which is calcium deficient. The alkalinity of water also helps in mobilizing fluoride from fluorite (CaF2). Fluoride exposure in humans is related to (1) fluoride concentration in drinking water, (2) duration of consumption, and (3) climate of the area. In hotter climates where water consumption is greater, exposure doses of fluoride need to be modified based on mean fluoride intake. Various cost-effective and simple procedures for water defluoridation techniques are already known, but the benefits of such techniques have not reached the rural affected population due to limitations. Therefore, there is a need to develop workable strategies to provide fluoride-safe drinking water to rural communities. The study investigated the geochemistry and occurrence of fluoride and its contamination in groundwater, human exposure, various adverse health effects, and possible remedial measures from fluoride toxicity effects.

  18. Development of technology and equipment for manufacturing fluorides rare-earths via non-aqueous method

    International Nuclear Information System (INIS)

    Chatalov, V.V.; Kozlov, O.I.; Machirev, V.P.; Zvonarev, E.N.

    1998-01-01

    Full text: The works on technology and equipment for rare earths (RE) fluorides are very scarce. Presently RE-fluorides are manufactured by various methods. Conventionally they can be divided into two main groups. The first group comprises methods based on precipitation of fluorides from soluble salts of corresponding metals by fluohydric acid (aqueous methods) with following thermal decomposition of aquatic fluorides obtained until anhydric state is reached. The second group (called dry, gaseous or non-aqueous) comprises methods based on direct fluorizating (by fluorine hydride, fluor or other fluorating agents) have several important advantages compared to the aqueous methods: the fluorides obtained are anhydrous; the operations of fluoride precipitation, washing, decantation, filtration are excluded as well as their drying and calcination. The process of calcination is, as a rule, accompanied by pyrohydrolysis. The products manufactured by precipitation are inferior to those obtained by the non-aqueous technique. The world production practice uses both groups of methods. Nevertheless, the method of gaseous hydrofluorination is preferable. In all non-aqueous processes the initial materials are oxides RE which interact with gaseous fluorine hydride. The initial materials - oxides are obtained by thermal decomposition of carbonates, hydroxides, oxalates and so on. One of the best type of apparatus for thermal decomposition processes is a horizontal ring shaped vibrating apparatus with direct heating. The RE - fluorides is synthesized by way of RE-oxide interacting with hydrogen fluoride at 200-550 deg C in single continuous operation: (RE) 2 O 3 + 6 HF → 2 (RE)F 3 + 3 H 2 0 The apparatus consists of a nickel horizontal two tube screw. Reaction time is varied from 2 to 6 hours; the productivity of reactor is defined by feed screw rotation and initial material bulk density. Hydrogen fluoride was passing the reactor opposite to the solid phase. The degree

  19. Dynamics of ligand exchange and association processes in solutions of transition 3d-metal fluorides

    International Nuclear Information System (INIS)

    Nazmutdinova, G.A.; Shtyrlin, V.G.; Zakharov, A.V.; Sal'nikov, Yu.I.

    1993-01-01

    By 19 NMR in combination with ESR spectroscopy rate constants and activation parameters of fluoride-ion exchange reactions in solutions of VOF 5 3- and FeF 6 3- complexes were determined. Associative character of the studied reactions of ligand exchange is shown. Dependence of fluoride complex reactivity on the charge, electron structure of the central ion and formation of hydrogen bonds of coordinated F - ions with solvent molecules was demonstrated. Stability constants, rates of formation and dissociation of intercomplex associates in fluoride solutions were ascertained

  20. Use of Iron (II Salts and Complexes for the Production of Soil Amendments from Organic Solid Wastes

    Directory of Open Access Journals (Sweden)

    Amerigo Beneduci

    2012-01-01

    Full Text Available A method to obtain rapidly stabilized composts for crops from solid organic wastes is evaluated. Here we used a laboratory scale reaction chamber where solid waste treatment was performed under strictly controlled temperature and pressure conditions. The row organic waste was mixed with acid solutions containing iron (II ions either in the fully hydrated form or in the form of complexes with the diethylentriaminopentaacetic acid. Data from elemental analysis distribution and GC/MS analysis of the polar and non polar dissolved organic matter, clearly showed that Fe(II ions significantly enhance organic substrate oxidation of the initial solid waste, compared to a material obtained without the addition of the Fe(II ions to the raw organic matrix. These results suggest that Fe(II ions might be involved in a catalytic oxidation pathway that would be activated under the experimental conditions used. The extent of the oxidation process was evaluated by the value of the C/N ratio and, qualitatively, by the molecular composition of the dissolved organic matter. After about 6 hours of incubation, dark-brown and dry organic matrices were obtained with C/N ratio as low as 12 and a high degree of oxidative decomposition into low-molecular-weight compounds at high oxidation state.

  1. The synthesis and structural characterization of novel transition metal fluorides

    Energy Technology Data Exchange (ETDEWEB)

    Casteel, W.J. Jr.

    1992-09-01

    High purity KMF[sub 6] and K[sub 2]MF[sub 6] salts (M = Mo,Re, Ru, Os, Ir, Pt) are obtained from reduction hexafluorides. A rhombohedral unit cell is observed for KReF[sub 6]. Fluoride ion capture by Lewis acids from the hexafluorometallate (IV) salts affords high purity tetrafluorides for M = Mo, Re, Ru, Os, and Pd. The structure of RuF[sub 4] is determined from X-ray synchrotron and neutron powder data. Unit cells based on theorthorhombic PdF[sub 4] type cell are derived from X-ray powder data for ReF[sub 4] and OsF[sub 4]. Fluoride ion capture from KAgF[sub 4] provides the thermally unstable trifluoride as a bright, red, diamagnetic solid. The structure solution of AgF[sub 3] and redetermination of the AuF[sub 3] structure from X-ray synchrotron and neutron powder data demonstrate that the two are isostnictural. Thermal decomposition product of AgF[sub 3] is the mixed valence compound Ag[sup II]Ag[sub 2][sup III]F[sub 8]. Several new salts containing the (Ag - F)[sub n][sup n+] chain cation are prepared. The first linear (Ag - F)[sub n][sup n+] chain is observed in AgF[sup +]BF[sub 4 [sup [minus

  2. Fluoride-associated ultrastructural changes and apoptosis in human renal tubule: a pilot study.

    Science.gov (United States)

    Quadri, J A; Sarwar, S; Sinha, A; Kalaivani, M; Dinda, A K; Bagga, A; Roy, T S; Das, T K; Shariff, A

    2018-01-01

    The susceptibility of the kidneys to fluoride toxicity can largely be attributed to its anatomy and function. As the filtrate moves along the complex tubular structure of each nephron, it is concentrated in the proximal and distal tubules and collecting duct. It has been frequently observed that the children suffering from renal impairments also have some symptoms of dental and skeletal fluorosis. The findings suggest that fluoride somehow interferes with renal anatomy and physiology, which may lead to renal pathogenesis. The aim of this study was to evaluate the fluoride-associated nephrotoxicity. A total of 156 patients with childhood nephrotic syndrome were screened and it was observed that 32 of them had significantly high levels ( p ≤ 0.05) of fluoride in urine (4.01 ± 1.83 ppm) and serum (0.1 ± 0.013 ppm). On the basis of urinary fluoride concentration, patients were divided into two groups, namely group 1 (G-1) ( n = 32) containing normal urine fluoride (0.61 ± 0.17 ppm) and group 2 (G-2) ( n = 32) having high urine fluoride concentration (4.01 ± 1.83 ppm). Age-matched healthy subjects ( n = 33) having normal levels of urinary fluoride (0.56 ± 0.15 ppm) were included in the study as control (group 0 (G-0)). Kidney biopsies were taken from G-1 and G-2 only, who were subjected to ultrastructural (transmission electron microscopy) and apoptotic (terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling) analysis. Various subcellular ultrastructural changes including nuclear disintegration, chromosome condensation, cytoplasmic ground substance lysis, and endoplasmic reticulum blebbing were observed. Increased levels of apoptosis were observed in high fluoride group (G-2) compared to normal fluoride group (G-1). Various degrees of fluoride-associated damages to the architecture of tubular epithelia, such as cell swelling and lysis, cytoplasmic vacuolation, nuclear condensation, apoptosis, and necrosis, were observed.

  3. A calcite permeable reactive barrier for the remediation of Fluoride from spent potliner (SPL) contaminated groundwater

    DEFF Research Database (Denmark)

    Turner, B.D.; Binning, Philip John; Sloan, S.W.

    2008-01-01

    The use of calcite (CaCO3) as a substrate for a permeable reactive barrier (PRB) for removing fluoride from contaminated groundwater is proposed and is illustrated by application to groundwater contaminated by spent potliner leachate (SPL), a waste derived from the aluminium smelting process...... leachate indicate that the complex chemical matrix of the SPL leachate can impact fluoride removal significantly. For SPL contaminant mixtures, fluoride removal is initially less than expected from idealized, pure, solutions. However, with time, the effect of other contaminants on fluoride removal...... diminishes. Column tests also show that pH control is important for optimizing fluoride removal with the mass removed increasing with decreasing pH. Barrier pH can be regulated by CO2 addition with the point of injection being critical for optimising the remediation performance. Experimental and model...

  4. Metal Fluorides, Metal Chlorides and Halogenated Metal Oxides as Lewis Acidic Heterogeneous Catalysts. Providing Some Context for Nanostructured Metal Fluorides.

    Science.gov (United States)

    Lennon, David; Winfield, John M

    2017-01-28

    Aspects of the chemistry of selected metal fluorides, which are pertinent to their real or potential use as Lewis acidic, heterogeneous catalysts, are reviewed. Particular attention is paid to β-aluminum trifluoride, aluminum chlorofluoride and aluminas γ and η, whose surfaces become partially fluorinated or chlorinated, through pre-treatment with halogenating reagents or during a catalytic reaction. In these cases, direct comparisons with nanostructured metal fluorides are possible. In the second part of the review, attention is directed to iron(III) and copper(II) metal chlorides, whose Lewis acidity and potential redox function have had important catalytic implications in large-scale chlorohydrocarbons chemistry. Recent work, which highlights the complexity of reactions that can occur in the presence of supported copper(II) chloride as an oxychlorination catalyst, is featured. Although direct comparisons with nanostructured fluorides are not currently possible, the work could be relevant to possible future catalytic developments in nanostructured materials.

  5. Thermodynamics of soluble fission products cesium and iodine in the Molten Salt Reactor

    NARCIS (Netherlands)

    Capelli, E.; Beneš, O.; Konings, R.J.M.

    2018-01-01

    The present study describes the full thermodynamic assessment of the Li,Cs,Th//F,I system. The existing database for the relevant fluoride salts considered as fuel for the Molten Salt Reactor (MSR) has been extended with two key fission products, cesium and iodine. A complete evaluation of all

  6. Behaviour of metals and alloys in molten fluoride media

    International Nuclear Information System (INIS)

    Fabre, St.

    2009-01-01

    Fluoride salts are contemplated for Generation IV nuclear systems which structural materials need to resist corrosion at high temperatures. Corrosion of metals in molten fluorides has been investigated in support of the Molten Salt Reactor's development and led to an optimized alloy, Hastelloy-N, but it lacked fundamentals data for the comprehension of materials' degradation mechanisms. The main objective of this work is then to help with the understanding of the corrosion behaviour of nickel and its alloys in fluoride salts. An experimental method was built up using electrochemical techniques and enabled to investigate the thermochemical conditions of the media and the influence of different parameters (media, temperature and quantity of impurities) on the behaviour of the materials. Most tests were performed in LiF-NaF mixtures between 800 and 1000 C. Pure metals can be classified as follows: Cr ≤ Fe ≤ Ni ≤ Mo ≤ W in increasing stability order and two specific behaviours were evidenced: Cr and Fe corrode in the melt, whereas Ni, Mo and W are stable, underlining the significance level of the redox couple controlling the reactions in the mixture. Moreover, corrosion current densities increase with temperature, fluoro-acidity and the quantity of dissolved oxide in the melt. Binary Ni-Cr alloys were also tested; selective attack of Cr is first observed before both elements are oxidized. Combining thermochemical calculations and experimental results enables to propose an approach to establish an optimized composition for a stable alloy. Immersion tests were finally achieved in addition to the electrochemical tests: interpretations of both methods were compared and completed. (author)

  7. Copolymerization and terpolymerization of carbon dioxide/propylene oxide/phthalic anhydride using a (salenCo(III complex tethering four quaternary ammonium salts

    Directory of Open Access Journals (Sweden)

    Jong Yeob Jeon

    2014-08-01

    Full Text Available The (salenCo(III complex 1 tethering four quaternary ammonium salts, which is a highly active catalyst in CO2/epoxide copolymerizations, shows high activity for propylene oxide/phthalic anhydride (PO/PA copolymerizations and PO/CO2/PA terpolymerizations. In the PO/PA copolymerizations, full conversion of PA was achieved within 5 h, and strictly alternating copolymers of poly(1,2-propylene phthalates were afforded without any formation of ether linkages. In the PO/CO2/PA terpolymerizations, full conversion of PA was also achieved within 4 h. The resulting polymers were gradient poly(1,2-propylene carbonate-co-phthalates because of the drift in the PA concentration during the terpolymerization. Both polymerizations showed immortal polymerization character; therefore, the molecular weights were determined by the activity (g/mol-1 and the number of chain-growing sites per 1 [anions in 1 (5 + water (present as impurity + ethanol (deliberately fed], and the molecular weight distributions were narrow (Mw/Mn, 1.05–1.5. Because of the extremely high activity of 1, high-molecular-weight polymers were generated (Mn up to 170,000 and 350,000 for the PO/PA copolymerization and PO/CO2/PA terpolymerization, respectively. The terpolymers bearing a substantial number of PA units (fPA, 0.23 showed a higher glass-transition temperature (48 °C than the CO2/PO alternating copolymer (40 °C.

  8. Chronic fluoride toxicity: dental fluorosis.

    Science.gov (United States)

    Denbesten, Pamela; Li, Wu

    2011-01-01

    Dental fluorosis occurs as a result of excess fluoride ingestion during tooth formation. Enamel fluorosis and primary dentin fluorosis can only occur when teeth are forming, and therefore fluoride exposure (as it relates to dental fluorosis) occurs during childhood. In the permanent dentition, this would begin with the lower incisors, which complete mineralization at approximately 2-3 years of age, and end after mineralization of the third molars. The white opaque appearance of fluorosed enamel is caused by a hypomineralized enamel subsurface. With more severe dental fluorosis, pitting and a loss of the enamel surface occurs, leading to secondary staining (appearing as a brown color). Many of the changes caused by fluoride are related to cell/matrix interactions as the teeth are forming. At the early maturation stage, the relative quantity of amelogenin protein is increased in fluorosed enamel in a dose-related manner. This appears to result from a delay in the removal of amelogenins as the enamel matures. In vitro, when fluoride is incorporated into the mineral, more protein binds to the forming mineral, and protein removal by proteinases is delayed. This suggests that altered protein/mineral interactions are in part responsible for retention of amelogenins and the resultant hypomineralization that occurs in fluorosed enamel. Fluoride also appears to enhance mineral precipitation in forming teeth, resulting in hypermineralized bands of enamel, which are then followed by hypomineralized bands. Enhanced mineral precipitation with local increases in matrix acidity may affect maturation stage ameloblast modulation, potentially explaining the dose-related decrease in cycles of ameloblast modulation from ruffle-ended to smooth-ended cells that occur with fluoride exposure in rodents. Specific cellular effects of fluoride have been implicated, but more research is needed to determine which of these changes are relevant to the formation of fluorosed teeth. As further

  9. Acute toxicity of ingested fluoride.

    Science.gov (United States)

    Whitford, Gary Milton

    2011-01-01

    This chapter discusses the characteristics and treatment of acute fluoride toxicity as well as the most common sources of overexposure, the doses that cause acute toxicity, and factors that can influence the clinical outcome. Cases of serious systemic toxicity and fatalities due to acute exposures are now rare, but overexposures causing toxic signs and symptoms are not. The clinical course of systemic toxicity from ingested fluoride begins with gastric signs and symptoms, and can develop with alarming rapidity. Treatment involves minimizing absorption by administering a solution containing calcium, monitoring and managing plasma calcium and potassium concentrations, acid-base status, and supporting vital functions. Approximately 30,000 calls to US poison control centers concerning acute exposures in children are made each year, most of which involve temporary gastrointestinal effects, but others require medical treatment. The most common sources of acute overexposures today are dental products - particularly dentifrices because of their relatively high fluoride concentrations, pleasant flavors, and their presence in non-secure locations in most homes. For example, ingestion of only 1.8 ounces of a standard fluoridated dentifrice (900-1,100 mg/kg) by a 10-kg child delivers enough fluoride to reach the 'probably toxic dose' (5 mg/kg body weight). Factors that may influence the clinical course of an overexposure include the chemical compound (e.g. NaF, MFP, etc.), the age and acid-base status of the individual, and the elapsed time between exposure and the initiation of treatment. While fluoride has well-established beneficial dental effects and cases of serious toxicity are now rare, the potential for toxicity requires that fluoride-containing materials be handled and stored with the respect they deserve. Copyright © 2011 S. Karger AG, Basel.

  10. Electrochemical Reduction of solid UO2 in Molten Fluoride Salts

    International Nuclear Information System (INIS)

    Gibilaro, Mathieu; Cassayre, Laurent; Massot, Laurent; Chamelot, Pierre; Malmbeck, Rikard; Dugne, Olivier; Allegri, Patrick

    2010-01-01

    The direct electrochemical reduction of UO 2 solid pellets was carried out in LiF-CaF 2 (+ 2wt % Li 2 O) at 850 deg. C. An inert gold anode was used instead of the usual reactive sacrificial carbon anode. In this case, reduction of oxide ions yields O 2 gas evolution on the anode. Electrochemical characterisations of UO 2 pellets have been performed by linear sweep voltammetry at 10 mV/s and reduction waves associated to its direct reduction have been observed at a potential 150 mV more positive in comparison with the solvent reduction. Then, galvano-static electrolyses runs have been realised and products were characterised by SEM-EDX, EPMA/WDS and XRD. In one of the runs, uranium oxide was partially reduced and three phases were observed: non reduced UO 2 in the centre, pure metallic uranium on the external layer and an intermediate phase representing the initial stage of reduction taking place at the grain boundaries. In another run, the UO 2 sample was fully reduced. Due to oxygen removal, the U matrix had a typical coral-like structure which is characteristic of the pattern observed after the electroreduction of solid oxides. (authors)

  11. Cladding Alloys for Fluoride Salt Compatibility Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Muralidharan, Govindarajan [ORNL; Wilson, Dane F [ORNL; Santella, Michael L [ORNL; Holcomb, David Eugene [ORNL

    2011-05-01

    This interim report provides an overview of several candidate technologies for cladding nickel-based corrosion protection layers onto high-temperature structural alloys. The report also provides a brief overview of the welding and weld performance issues associated with joining nickel-clad nickel-based alloys. From the available techniques, two cladding technologies were selected for initial evaluation. The first technique is a line-of-sight method that would be useful for coating large structures such as vessel interiors or large piping. The line-of-sight method is a laser-based surface cladding technique in which a high-purity nickel powder mixed into a polymer binder is first sprayed onto the surface, baked, and then rapidly melted using a high power laser. The second technique is a vapor phase technique based on the nickel-carbonyl process that is suitable for coating inaccessible surfaces such as the interior surfaces of heat exchangers. The final project report will feature an experimental evaluation of the performance of the two selected cladding techniques.

  12. Chemistry and technology of Molten Salt Reactors - history and perspectives

    International Nuclear Information System (INIS)

    Uhlir, Jan

    2007-01-01

    Molten Salt Reactors represent one of promising future nuclear reactor concept included also in the Generation IV reactors family. This reactor type is distinguished by an extraordinarily close connection between the reactor physics and chemical technology, which is given by the specific features of the chemical form of fuel, representing by molten fluoride salt and circulating through the reactor core and also by the requirements of continuous 'on-line' reprocessing of the spent fuel. The history of Molten Salt Reactors reaches the period of fifties and sixties, when the first experimental Molten Salt Reactors were constructed and tested in ORNL (US). Several molten salt techniques dedicated to fresh molten salt fuel processing and spent fuel reprocessing were studied and developed in those days. Today, after nearly thirty years of discontinuance, a renewed interest in the Molten Salt Reactor technology is observed. Current experimental R and D activities in the area of Molten Salt Reactor technology are realized by a relatively small number of research institutions mainly in the EU, Russia and USA. The main effort is directed primarily to the development of separation processes suitable for the molten salt fuel processing and reprocessing technology. The techniques under development are molten salt/liquid metal extraction processes, electrochemical separation processes from the molten salt media, fused salt volatilization techniques and gas extraction from the molten salt medium

  13. Concept of the demonstration molten salt unit for the transuranium elements transmutations

    International Nuclear Information System (INIS)

    Alekseev, P.; Dudnikov, A.; Prusakov, V.; Subbotin, S.; Zakirov, R.; Lelek, V.; Peka, I.

    1999-01-01

    Fluorine reprocessing is discussed of spent fuel and of fluoride molten salt reactor in critical and subcritical modes for plutonium and minor actinides burning. International collaboration for creation of such system is proposed. Additional neutron source in the core will have positive influence on the transmutation processes in the reactor. Demonstration critical molten salt reactor of small power capacity will permit to decide the most part of problems inherent to large critical reactors and subcritical drivers. It could be expected that fluoride molten salt transmuter can work without accelerator as a critical reactor. (author)

  14. Fluoride mouthrinses for preventing dental caries in children and adolescents.

    Science.gov (United States)

    Marinho, Valeria C C; Chong, Lee Yee; Worthington, Helen V; Walsh, Tanya

    2016-07-29

    Fluoride mouthrinses have been used extensively as a caries-preventive intervention in school-based programmes and by individuals at home. This is an update of the Cochrane review of fluoride mouthrinses for preventing dental caries in children and adolescents that was first published in 2003. The primary objective is to determine the effectiveness and safety of fluoride mouthrinses in preventing dental caries in the child and adolescent population.The secondary objective is to examine whether the effect of fluoride rinses is influenced by:• initial level of caries severity;• background exposure to fluoride in water (or salt), toothpastes or reported fluoride sources other than the study option(s); or• fluoride concentration (ppm F) or frequency of use (times per year). We searched the following electronic databases: Cochrane Oral Health's Trials Register (whole database, to 22 April 2016), the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library, 2016, Issue 3), MEDLINE Ovid (1946 to 22 April 2016), Embase Ovid (1980 to 22 April 2016), CINAHL EBSCO (the Cumulative Index to Nursing and Allied Health Literature, 1937 to 22 April 2016), LILACS BIREME (Latin American and Caribbean Health Science Information Database, 1982 to 22 April 2016), BBO BIREME (Bibliografia Brasileira de Odontologia; from 1986 to 22 April 2016), Proquest Dissertations and Theses (1861 to 22 April 2016) and Web of Science Conference Proceedings (1990 to 22 April 2016). We undertook a search for ongoing trials on the US National Institutes of Health Trials Register (http://clinicaltrials.gov) and the World Health Organization International Clinical Trials Registry Platform. We placed no restrictions on language or date of publication when searching electronic databases. We also searched reference lists of articles and contacted selected authors and manufacturers. Randomised or quasi-randomised controlled trials where blind outcome assessment was stated or

  15. Fluoride level in saliva after bonding orthodontic brackets with a fluoride containing adhesive

    NARCIS (Netherlands)

    Ogaard, B; Arends, J; Helseth, H; Dijkman, G; vanderKuijl, M

    The fluoride level in saliva is considered an important parameter in caries prevention. Elevation of the salivary fluoride level by a fluoride-releasing orthodontic bonding adhesive would most likely be beneficial in the prevention of enamel caries. In this study, the fluoride level in saliva was

  16. Urinary fluoride excretion in preschool children after intake of fluoridated milk and use of fluoride-containing toothpaste

    DEFF Research Database (Denmark)

    Norman, M; Twetman, S; Hultgren Talvilahti, A

    2017-01-01

    Objective: To assess the urinary fluoride excretion in preschool children after drinking fluoridated milk with 0.185 mg F and 0.375 mg F and to study the impact of use of fluoride toothpaste. Basic research design: Double-blind cross-over study. Participants: Nine healthy children, 2.5-4.5 years...

  17. Heat transfer investigation of molten salts under laminar and turbulent flow regimes

    International Nuclear Information System (INIS)

    Srivastava, A.K.; Vaidya, A.M.; Maheshwari, N.K.; Vijayan, P.K.

    2014-01-01

    High temperature reactor and solar thermal power plants use Molten Salt as a coolant, as it has low melting point and high boiling point, enabling us to operate the system at low pressure. Molten fluoride salt (eutectic mixture of LiF-NaF-KF) and molten nitrate salt (mixture of NaNO 3 and KNO 3 in 60:40 ratios by weight) are proposed as a candidate coolant for High Temperature Reactors (HTR) and solar power plant respectively. BARC is developing a 600 MWth pebble bed high temperature reactor, cooled by natural circulation of fluoride salt and capable of supplying process heat at 1000℃ to facilitate hydrogen production by splitting water. Beside this, BARC is also developing a 2MWe solar power tower system using molten nitrate salt as a primary coolant and storage medium. In order to design this, it is necessary to study the heat transfer characteristics of various molten salts. Most of the previous studies related to molten salts are based on the experimental works. These experiments essentially measured the physical properties of molten salts and their heat transfer characteristics. Ferri et al. introduced the property definitions for molten salts in the RELAP5 code to perform transient simulations at the ProvaCollettoriSolari (PCS) test facility. In this paper, a CFD analysis has been performed to study the heat transfer characteristics of molten fluoride salt and molten nitrate salt flowing in a circular pipe for various regimes of flow. Simulation is performed with the help of in-house developed CFD code, NAFA, acronym for Numerical Analysis of Flows in Axi-symmetric geometries. Uniform velocity and temperature distribution are set as the inlet boundary condition and pressure is employed at the outlet boundary condition. The inlet temperature for all simulation is set as 300℃ for nitrate salt and 500℃ for fluoride salt and the operating pressure is 1 atm in both the cases

  18. Salt cookbook

    CERN Document Server

    Saha, Anirban

    2015-01-01

    If you are a professional associated with system and infrastructure management, looking at automated infrastructure and deployments, then this book is for you. No prior experience of Salt is required.

  19. Water Fluoridation Reporting System (Public Water Systems)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Water Fluoridation Reporting System (WFRS) has been developed to provide tools to assist states in managing fluoridation programs. WFRS is designed to track all...

  20. ADSORPTIVE REMOVAL OF FLUORIDE FROM WATER USING ...

    African Journals Online (AJOL)

    Preferred Customer

    Currently available treatment methods for removal of excess fluoride from water are broadly divided into three ... the application of nanoparticles as sorbents for fluoride removal. Sundaram [26] studied the ... Characterization of adsorbent.

  1. No Calcium-Fluoride-Like Deposits Detected in Plaque Shortly after a Sodium Fluoride Mouthrinse

    OpenAIRE

    Vogel, G.L.; Tenuta, L.M.A.; Schumacher, G.E.; Chow, L.C.

    2010-01-01

    Plaque ‘calcium-fluoride-like’ (CaF2-like) and fluoride deposits held by biological/bacterial calcium fluoride (Ca-F) bonds appear to be the source of cariostatic concentrations of fluoride in plaque fluid. The aim of this study was to quantify the amounts of plaque fluoride held in these reservoirs after a sodium fluoride rinse. 30 and 60 min after a 228 μg/g fluoride rinse, plaque samples were collected from 11 volunteers. Each sample was homogenized, split into 2 aliquots (aliquots 1 and 2...

  2. Acute toxicity of uranium hexafluoride, uranyl fluoride and hydrogen fluoride

    International Nuclear Information System (INIS)

    Just, R.A.

    1988-01-01

    Uranium hexafluoride (UF 6 ) released into the atmosphere will react rapidly with moisture in the air to form the hydrolysis products uranyl fluoride (UO 2 F 2 ) and hydrogen fluoride (HF). Uranium compounds such as UF 6 and UO 2 F 2 exhibit both chemical toxicity and radiological effects, while HF exhibits only chemical toxicity. This paper describes the development of a methodology for assessing the human health consequences of a known acute exposure to a mixture of UF 6 , UO 2 F 2 , and HF. 4 refs., 2 figs., 5 tabs

  3. Symbiotic molten-salt systems coupled with accelerator molten-salt breeder (AMSB) or inertial-confined fusion hybrid molten-salt breeder (IHMSB) and their comparison

    International Nuclear Information System (INIS)

    Furukawa, K.

    1984-01-01

    Two types of breeder systems are proposed. One is the combined system of Accelerator Molten-Salt Breeder (AMSB) and Molten-Salt Converter Reactor (MSCR), and the other is the combined system of Inertial-confined Fusion Hybrid Molten-Salt Breeder (IHMSB) and modified MSCR. Both apply the molten-fluorides and have technically deep relations. AMSB would be much simpler and have already high technical feasibility. This will become economical the Th breeder system having a doubling time shorter than ten years and distributing any size of power stations MSCR. (orig.) [de

  4. Effects of fluorides on plants

    Energy Technology Data Exchange (ETDEWEB)

    Yamazoe, F

    1975-11-01

    Fluorine compounds known to be air pollutants, such as hydrogen fluoride and silicon tetrachloride, are highly poisonous to plants even at ppm - ppb levels. As solid microparticles, acidic sodium fluoride and cryolite cause problems by adhering to plant leaves and absorbing into plant bodies. Plants are classified by their susceptibility to hydrogen fluoride: gladiolus, apricot, buckwheat, turnip and Vaccinium vitis-idaea are most susceptible showing slight injury at less than 5 ppb for 7-9 days; maize, pepper, and dahlia are fairly susceptible, followed by azalea, rose, lilac, and alfalfa, then by oak and tomato. Gladiolus is used as an indicator plant. The exposure factor for one species was known. The symptoms of plants exposed to gaseous fluorine compounds are described in detail at various concentrations. The causal mechanism of the injuries due to fluorine compounds is described in detail, with the method of determining the fluorine content of plant parts. 7 references.

  5. Photosynthesis of ammonium uranous fluoride

    International Nuclear Information System (INIS)

    El-Fekey, S.A.; Zaki, M.R.; Farah, M.Y.

    1975-01-01

    This study pertains to utilisation of solar energy for ethanol photosynthesis of ammonium uranous fluoride, that satisfies nuclear specifications needed for calcio- or magnesiothermy. Insolation in autumn using 4-10% ethanol in 5-20 g uranium/litre at initial pH 3.25 gave practically 99.8% yield in two hours, independant of 1.0 to 2.0 stoichiometric NH 4 F. With ultraviolet light, the yield varied between 30 and 60%, even after four hours irradiation. Stirring and heating to 60 0 C raised the tap density of the dried double fluorides from 1.48 at 30 0 C, to 1.85 g/cm 3 at 60 0 C. The texture increased also in fineness to 100% 50μ aggregates. The powders satisfy nuclear purity specifications. Thermograms indicated preferential decomposition of double fluoride at 375 0 C in controlled atmosphere to obtain nuclear pure anhydrous uranium tetrafluoride

  6. Anhydrous hydrogen fluoride electrolyte battery. [Patent application

    Science.gov (United States)

    Not Available

    1972-06-26

    It is an object of the invention to provide a primary cell or battery using ammonium fluoride--anhydrous hydrogen fluoride electrolyte having improved current and power production capabilities at low temperatures. It is operable at temperatures substantially above the boiling point of hydrogen fluoride. (GRA)

  7. Organoboron compounds as Lewis acid receptors of fluoride ions in polymeric membranes.

    Science.gov (United States)

    Jańczyk, Martyna; Adamczyk-Woźniak, Agnieszka; Sporzyński, Andrzej; Wróblewski, Wojciech

    2012-07-06

    Newly synthesized organoboron compounds - 4-octyloxyphenylboronic acid (OPBA) and pinacol ester of 2,4,6-trifluorophenylboronic acid (PE-PBA) - were applied as Lewis acid receptors of fluoride anions. Despite enhanced selectivity, the polymer membrane electrodes containing the lipophilic receptor OPBA exhibited non-Nernstian slopes of the responses toward fluoride ions in acidic conditions. Such behavior was explained by the lability of the B-O bond in the boronic acids, and the OH(-)/F(-) exchange at higher fluoride content in the sample solution. In consequence, the stoichiometry of the OPBA-fluoride complexes in the membrane could vary during the calibration, changing the equilibrium concentration of the primary anion in membrane and providing super-Nernstian responses. The proposed mechanism was supported by (19)F NMR studies, which indicated that the fluoride complexation proceeds more effectively in acidic solution leading mainly to PhBF(3)(-) species. Finally, the performances of the membranes based on the phenylboronic acid pinacol ester, with a more stable B-O bond, were tested. As it was expected, Nernstian fluoride responses were recorded for such membranes with worsened fluoride selectivity. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Caries prevalence and fluoride use in low SES children in Clermont-Ferrand (France).

    Science.gov (United States)

    Tubert-Jeannin, S; Riordan, P J; Manevy, R; Lecuyer, M M; Pegon-Machat, E

    2009-03-01

    To evaluate the association between dental caries experience and preventive behaviours of children residing in a deprived area in Clermont-Ferrand (France). All 4-5 yr-olds attending nine schools in deprived areas of the city were invited to participate and 81% (n=282) consented and were examined. Dental caries was recorded at the dentine threshold. Parents completed a questionnaire concerning family demographics and the child's use of fluoride. Non-parametric tests and logistic regression assessed the relative importance of SES and fluoride variables on dental status (dt>1). Fifty four (19%) of the examined children were living in families with an immigrant background, 33% were fully covered by the national health insurance programme for deprived families. Caries experience was high; mean dft was 1.94 (3.31) and 30% of the children had >1 carious teeth. Thirty percent of the families reported using fluoridated salt. Tooth brushing once daily was reported for 39% and twice daily for 26%. Parents declared supervising tooth brushing for 60%. Two thirds of the children, according to their parents, used fluoride supplement between birth and two years. Supervised tooth brushing was significantly correlated with lower mean dt scores. Systemic fluoride use was poorly related to dental caries Immigrant background, family size, type of health insurance and mother's unemployment were significantly correlated with caries prevalence. In multivariate analysis, immigrant status, supervised tooth brushing and parental knowledge about fluoride in toothpastes were significant caries predictors. The majority of low SES children did not practice effective caries prevention; few reported twice daily brushing with fluoride toothpaste. Caries experience was very high and much was untreated. Immigrant status, supervised tooth brushing and parental knowledge about fluoride in toothpastes were significant caries predictors.

  9. SBIR-Long fluoride fiber

    Science.gov (United States)

    Jaeger, Raymond E.; Vacha, Lubos J.

    1987-08-01

    This report summarizes results obtained under a program aimed at developing new techniques for fabricating long lengths of heavy metal fluoride glass (HMFG) optical fiber. A new method for overcladding conventional HMFG preforms with a low melting oxide glass was developed, and improvements in the rotational casting method were made to increase preform length. The resulting composite glass canes consist of a fluoride glass overcoat layer to enhance strength and chemical durability. To show feasibility, prototype optical fiber preforms up to 1.6 cm in diameter with lengths of 22 cm were fabricated. These were drawn into optical fibers with lengths up to 900 meters.

  10. Decomposição de amostras de solos assistida por radiação microondas: estratégia para evitar a formação de fluoretos insolúveis Microwave-assisted decomposition of soil samples: strategies to avoid formation of insoluble fluoride salts

    Directory of Open Access Journals (Sweden)

    Edivan Carvalho Vieira

    2005-07-01

    concentrated HF and the remaining fluoride ions were complexed by adding boric acid. This solution was mixed with the liquid phase of the acid digest. Elemental analysis of the acid digests was performed by inductively coupled plasma optical emission spectrometry (ICP-OES. The accuracy of the procedure was confirmed by applying it to samples provided by the International Soil-Analytical Exchange (ISE- Wageningen Agricultural University, Netherlands and to certified soil reference material from the National Institute of Standards & Technology (NIST, SRM 2709. The following elemental recovery (% was obtained: 100.0 ± 2.6; 99.5 ± 1.9; 108.5 ± 2.7; 94.6 ± 8.9; 92.2 ± 9.7; 95.7 ± 1.8; 96.7 ± 2.7; 95.2 ± 0.6; 103.6 ± 2.6 and 96.1 ± 1.6 for Al, Ba, Ca, Cr, Cu, Fe, Mg, Mn, V, and Zn, respectively.

  11. Conceptual design of Indian molten salt breeder reactor

    International Nuclear Information System (INIS)

    Vijayan, P.K.; Basak, A.; Dulera, I.V.; Vaze, K.K.; Basu, S.; Sinha, R.K.

    2014-01-01

    The fuel in a molten salt breeder reactor is in the form of a continuously circulating molten salt. Fluoride based salts have been almost universally proposed. A crucial part for achieving reasonable breeding in such reactors is the need to reprocess the salt continuously, either online or in batch mode. This constitutes a major technological challenge for this type of reactors. India has recently started carrying out fundamental studies so as to arrive at a conceptual design of Indian Molten Salt Breeder Reactor (IMSBR). Presently various design options and possibilities are being studied from the point of view of reactor physics and thermal hydraulic design. In parallel fundamental studies as regards various molten salts have also been initiated. This paper would discuss conceptual design of these reactors, as well as associated issues and technologies

  12. Complexation of tauro- and glyco-conjugated bile salts with alpha-cyclodextrin and hydroxypropyl-alpha-cyclodextrin studied by affinity capillary electrophoresis and molecular modelling

    DEFF Research Database (Denmark)

    Holm, Rene; Schönbeck, Jens Christian Sidney; Askjær, Sune

    2011-01-01

    The interaction of the bile salts taurocholate, taurodeoxycholate, taurochenodeoxycholate, glycocholate, glycodeoxycholate, and glycochenodeoxycholate present in man, dog, and rat with α-cyclodextrin and 2-hydroxypropyl-α-cyclodextrin was investigated by mobility shift affinity capillary electrop...

  13. The synthesis and structural characterization of novel transition metal fluorides

    Energy Technology Data Exchange (ETDEWEB)

    Casteel, Jr., William Jack [Univ. of California, Berkeley, CA (United States)

    1992-09-01

    High purity KMF6 and K2MF6 salts (M = Mo,Re, Ru, Os, Ir, Pt) are obtained from reduction hexafluorides. A rhombohedral unit cell is observed for KReF6. Fluoride ion capture by Lewis acids from the hexafluorometallate (IV) salts affords high purity tetrafluorides for M = Mo, Re, Ru, Os, and Pd. The structure of RuF4 is determined from X-ray synchrotron and neutron powder data. Unit cells based on theorthorhombic PdF4 type cell are derived from X-ray powder data for ReF4 and OsF4. Fluoride ion capture from KAgF4 provides the thermally unstable trifluoride as a bright, red, diamagnetic solid. The structure solution of AgF3 and redetermination of the AuF3 structure from X-ray synchrotron and neutron powder data demonstrate that the two are isostnictural. Thermal decomposition product of AgF3 is the mixed valence compound AgIIAg2IIIF8. Several new salts containing the (Ag - F)$n+\\atop{n}$ chain cation are prepared. The first linear (Ag - F)$n+\\atop{n}$ chain is observed in AgF+BF4- which crystallizes in a tetragonal unit. AgFAuF4 has a triclinic unit cell and is isostructural with CuFAuF4. AgFAuF6 has an orthorhombic unit cell and appears to be isostructural with AgFAsF6. A second mixed valence silver fluoride, AgIIAgIIIF5, is prepared, which magnetic measurements indicate is probably an AgF+ salt. Magnetic data for all of the AgF+ salts exhibit low magnitude, temperature independent paramagnetism characteristic of metallic systems. Cationic AG(II) in acidic AHF solutions is a powerful oxidizer, capable of oxidizing Xe to Xe(II) and O2 to O2+. Reactions with C6F6 and C3F6 suggest an electron capture

  14. Colorimetric determination of the fluoride ion - application to uranium metal and to uranous fluoride

    International Nuclear Information System (INIS)

    Hering, H.; Hure, J.; Legrand, S.

    1949-12-01

    In the determination described for fluoride in U metal, the U is brought into H 2 SO 4 solution by anodic oxidation, the fluo-silicic acid is distilled by entrainment in water vapor, and the F ion is determined in the distillate by using the fact that it complexes Zr and thus prevents the formation of the Zr-alizarin S lake. For F ion in UF 4 , the compound is dissolved in a Na 2 CO 3 -H 2 O 2 mixture, and F is determined in the solution by the colorimetric method described. (author)

  15. Silver diamine fluoride: a caries "silver-fluoride bullet".

    Science.gov (United States)

    Rosenblatt, A; Stamford, T C M; Niederman, R

    2009-02-01

    The antimicrobial use of silver compounds pivots on the 100-year-old application of silver nitrate, silver foil, and silver sutures for the prevention and treatment of ocular, surgical, and dental infections. Ag(+) kills pathogenic organisms at concentrations of linings, water purification systems, hospital gowns, and caries prevention. To distill the current best evidence relative to caries, this systematic review asked: Will silver diamine fluoride (SDF) more effectively prevent caries than fluoride varnish? A five-database search, reference review, and hand search identified 99 human clinical trials in three languages published between 1966 and 2006. Dual review for controlled clinical trials with the patient as the unit of observation, and excluding cross-sectional, animal, in vitro studies, and opinions, identified 2 studies meeting the inclusion criteria. The trials indicated that SDF's lowest prevented fractions for caries arrest and caries prevention were 96.1% and 70.3%, respectively. In contrast, fluoride varnish's highest prevented fractions for caries arrest and caries prevention were 21.3% and 55.7%, respectively. Similarly, SDF's highest numbers needed to treat for caries arrest and caries prevention were 0.8 (95% CI=0.5-1.0) and 0.9 (95% CI=0.4-1.1), respectively. For fluoride varnish, the lowest numbers needed to treat for caries arrest and prevention were 3.7 (95% CI=3.4-3.9) and 1.1 (95% CI=0.7-1.4), respectively. Adverse events were monitored, with no significant differences between control and experimental groups. These promising results suggest that SDF is more effective than fluoride varnish, and may be a valuable caries-preventive intervention. As well, the availability of a safe, effective, efficient, and equitable caries-preventive agent appears to meet the criteria of both the WHO Millennium Goals and the US Institute of Medicine's criteria for 21st century medical care.

  16. Accumulation of fluoride by plants and vegetables

    International Nuclear Information System (INIS)

    Njenga, L.W.; Kariuki, D.N.

    1994-01-01

    Fluoride in plant and vegetable samples has been determined using ion selective electrode. The analysis was carried out after ashing the sample on an open flame, adding perchloric acid and allowing the hydrogen fluoride to diffuse into sodium hydroxide layer.The results obtained show that kale and pumpkins can accumulate more than ten times their normal values of fluoride while plants were found to accumulate upto 100μg/g fluoride when exposed to highlevels of fluoride in water or soil. (author)

  17. Toxic effects of fluoride on organisms.

    Science.gov (United States)

    Zuo, Huan; Chen, Liang; Kong, Ming; Qiu, Lipeng; Lü, Peng; Wu, Peng; Yang, Yanhua; Chen, Keping

    2018-04-01

    Accumulation of excess fluoride in the environment poses serious health risks to plants, animals, and humans. This endangers human health, affects organism growth and development, and negatively impacts the food chain, thereby affecting ecological balance. In recent years, numerous studies focused on the molecular mechanisms associated with fluoride toxicity. These studies have demonstrated that fluoride can induce oxidative stress, regulate intracellular redox homeostasis, and lead to mitochondrial damage, endoplasmic reticulum stress and alter gene expression. This paper reviews the present research on the potential adverse effects of overdose fluoride on various organisms and aims to improve our understanding of fluoride toxicity. Copyright © 2018 Elsevier Inc. All rights reserved.

  18. Combined system of accelerator molten-salt breeder (AMSB) apd molten-salt converter reactor (MSCR)

    International Nuclear Information System (INIS)

    Furukawa, K.; Kato, Y.; Ohmichi, T.; Ohno, H.

    1983-01-01

    A design and research program is discUssed of the development of accelerator molten-salt breeder (AMSB) consisting of a proton accelerator and a molten fluoride target. The target simultaneously serves as a blanket for fissionable material prodUction. An addition of some amoUnt of fissile nuclides to a melt expands the AMSB potentialities as the fissionable material production increases and the energy generation also grows up to the level of self-provision. Besides the blanket salts may be used as nuclear fuel for molten-salt converter reactor (MSCR). The combined AM SB+MSCR system has better parameters as compared to other breeder reactors, molten-salt breeder reactors (MSBR) included

  19. Subcritical enhanced safety molten-salt reactor concept

    International Nuclear Information System (INIS)

    Alekseev, P.N.; Ignatiev, V.V.; Men'shikov, L.I.; Prusakov, V.N.; Ponomarev-Stepnoy, N.N.; Subbotin, S.A.; Krasnykh, A.K.; Rudenko, V.T.; Somov, L.N.

    1995-01-01

    The nuclear power and its fuel cycle safety requirements can be met in the main by providing nuclear power with subcritical molten salt reactors (SMSR) - 'burner' with an external neutron source. The utilized molten salt fuel is the decisive advantage of the SMSR over other burners. Fissile and fertile nuclides in the burner are solved in a liquid salt in the form of fluorides. This composition acts simultaneously as: a) fuel, b) coolant, c) medium for chemical partitioning and reprocessing. The effective way of reducing the external source power consists in the cascade neutron multiplication in the system of coupled reactors with suppressed feedback between them. (author)

  20. Fluoride remediation using floating macrophytes

    Directory of Open Access Journals (Sweden)

    Naba Kumar Mondal

    2014-04-01

    Full Text Available Six aquatic macrophytes, such as Pistia stratiotes, Ceratophyllum demersum, Nymphoides indica, Lemna major, Azolla pinnata,and Eichhornia crassipes were considered for remove fluoride from aqueous solution. Five different concentrations (10, 30, 50, and 100 ppm of fluoride solution were taken in 1 L plastic container. Fixed weight (20 g of macrophytes along with 500 ml fluoride solution was taken in each plastic container for 72 hours observation. Results demonstrated all the macrophytes show highest fluoride removal during 24 h to 48 h, but after 72 h their efficiency reduced drastically. The species N. indica showed better removal efficiency than other experimental macrophytes. In general, pigment measurement data indicated higher concentration at 72 h. However, Pistia sp. showed higher concentration of pigmentation at intermediate time interval (48 h. Higher level of dry weight to fresh weight ratio was recorded for L. major and A. pinnata at all concentrations, excepting at 10 ppm. In addition, all macrophytes showed lower RGR at higher concentration. Isotherm study indicated that macrophyte C. demersum is a good fitted with Freundlich and Langmuir isotherm whereas L. major with Langmuir isotherm during 24 hours.

  1. Unusual hydrogen bonding in L-cysteine hydrogen fluoride.

    Science.gov (United States)

    Minkov, V S; Ghazaryan, V V; Boldyreva, E V; Petrosyan, A M

    2015-08-01

    L-Cysteine hydrogen fluoride, or bis(L-cysteinium) difluoride-L-cysteine-hydrogen fluoride (1/1/1), 2C3H8NO2S(+)·2F(-)·C3H7NO2S·HF or L-Cys(+)(L-Cys···L-Cys(+))F(-)(F(-)...H-F), provides the first example of a structure with cations of the 'triglycine sulfate' type, i.e. A(+)(A···A(+)) (where A and A(+) are the zwitterionic and cationic states of an amino acid, respectively), without a doubly charged counter-ion. The salt crystallizes in the monoclinic system with the space group P2(1). The dimeric (L-Cys···L-Cys(+)) cation and the dimeric (F(-)···H-F) anion are formed via strong O-H···O or F-H···F hydrogen bonds, respectively, with very short O···O [2.4438 (19) Å] and F···F distances [2.2676 (17) Å]. The F···F distance is significantly shorter than in solid hydrogen fluoride. Additionally, there is another very short hydrogen bond, of O-H···F type, formed by a L-cysteinium cation and a fluoride ion. The corresponding O···F distance of 2.3412 (19) Å seems to be the shortest among O-H···F and F-H···O hydrogen bonds known to date. The single-crystal X-ray diffraction study was complemented by IR spectroscopy. Of special interest was the spectral region of vibrations related to the above-mentioned hydrogen bonds.

  2. Lithological Influences on Occurrence of High-Fluoride Waters in The Central Kenya Rift

    Science.gov (United States)

    Olaka, L. A.; Musolff, A.; Mulch, A.; Olago, D.; Odada, E. O.

    2013-12-01

    Within the East African rift, groundwater recharge results from the complex interplay of geology, land cover, geomorphology, climate and on going volcano-tectonic processes across a broad range of spatial and temporal scales. The interrelationships between these factors create complex patterns of water availability, reliability and quality. The hydrochemical evolution of the waters is further complex due to the different climatic regimes and geothermal processes going on in this area. High fluoridic waters within the rift have been reported by few studies, while dental fluorosis is high among the inhabitants of the rift. The natural sources of fluoride in waters can be from weathering of fluorine bearing minerals in rocks, volcanic or fumarolic activities. Fluoride concentration in water depends on a number of factors including pH, temperature, time of water-rock formation contact and geochemical processes. Knowledge of the sources and dispersion of fluoride in both surface and groundwaters within the central Kenya rift and seasonal variations between wet and dry seasons is still poor. The Central Kenya rift is marked by active tectonics, volcanic activity and fumarolic activity, the rocks are majorly volcanics: rhyolites, tuffs, basalts, phonolites, ashes and agglomerates some are highly fractured. Major NW-SE faults bound the rift escarpment while the rift floor is marked by N-S striking faults We combine petrographic, hydrochemistry and structural information to determine the sources and enrichment pathways of high fluoridic waters within the Naivasha catchment. A total of 120 water samples for both the dry season (January-February2012) and after wet season (June-July 2013) from springs, rivers, lakes, hand dug wells, fumaroles and boreholes within the Naivasha catchment are collected and analysed for fluoride, physicochemical parameters and stable isotopes (δ2 H, δ18 O) in order to determine the origin and evolution of the waters. Additionally, 30 soil and

  3. Alimentary fluoride intake in preschool children

    Directory of Open Access Journals (Sweden)

    Lencova Erika

    2011-10-01

    Full Text Available Abstract Background The knowledge of background alimentary fluoride intake in preschool children is of utmost importance for introducing optimal and safe caries preventive measures for both individuals and communities. The aim of this study was to assess the daily fluoride intake analyzing duplicate samples of food and beverages. An attempt was made to calculate the daily intake of fluoride from food and swallowed toothpaste. Methods Daily alimentary fluoride intake was measured in a group of 36 children with an average age of 4.75 years and an average weight of 20.69 kg at baseline, by means of a double plate method. This was repeated after six months. Parents recorded their child's diet over 24 hours and collected duplicated portions of food and beverages received by children during this period. Pooled samples of food and beverages were weighed and solid food samples were homogenized. Fluoride was quantitatively extracted from solid food samples by a microdiffusion method using hexadecyldisiloxane and perchloric acid. The content of fluoride extracted from solid food samples, as well as fluoride in beverages, was measured potentiometrically by means of a fluoride ion selective electrode. Results Average daily fluoride intake at baseline was 0.389 (SD 0.054 mg per day. Six months later it was 0.378 (SD 0.084 mg per day which represents 0.020 (SD 0.010 and 0.018 (SD 0.008 mg of fluoride respectively calculated per kg bw/day. When adding the values of unwanted fluoride intake from the toothpaste shown in the literature (0.17-1.21 mg per day the estimate of the total daily intake of fluoride amounted to 0.554-1.594 mg/day and recalculated to the child's body weight to 0.027-0.077 mg/kg bw/day. Conclusions In the children studied, observed daily fluoride intake reached the threshold for safe fluoride intake. When adding the potential fluoride intake from swallowed toothpaste, alimentary intake reached the optimum range for daily fluoride intake

  4. Molten salt burner fuel behaviour and treatment

    International Nuclear Information System (INIS)

    Ignatiev, V.V.; Zakirov, R.Y.; Grebenkine, K.F.

    2001-01-01

    The objective of this paper is to discuss the feasibility of molten salt reactor technology for treatment of Pu, minor actinides and fission products, when the reactor and fission product clean-up unit are planned as an integral system. This contribution summarises the available R and D which led to selection of the fuel compositions for the molten salt reactor of the TRU burner type (MSB). Special characteristics of behaviour of TRUs and fission products during power operation of MSB concepts are presented. The present paper briefly reviews the processing developments underlying the prior molten salt reactor programmes and relates them to the separation requirements of the MSB concept, including the permissible range of processing cycle times and removal times. Status and development needs in the thermodynamic properties of fluorides, fission product clean-up methods and container materials compatibility with the working fluids for the fission product clean-up unit are discussed. (authors)

  5. Preliminary Safeguards Assessment for the Pebble-Bed Fluoride High-Temperature Reactor (PB-FHR) Concept

    Energy Technology Data Exchange (ETDEWEB)

    Disser, Jay; Arthur, Edward; Lambert, Janine

    2016-09-01

    This report examines a preliminary design for a pebble bed fluoride salt-cooled high temperature reactor (PB-FHR) concept, assessing it from an international safeguards perspective. Safeguards features are defined, in a preliminary fashion, and suggestions are made for addressing further nuclear materials accountancy needs.

  6. Bath Salts

    Science.gov (United States)

    ... deaths and been blamed for a handful of suicides and murders. Two of the chemicals in bath salts (mephedrone and MDPV) are Schedule I class drugs. That means they have a high potential for abuse and no accepted medical use . People who are ...

  7. Eukaryotic resistance to fluoride toxicity mediated by a widespread family of fluoride export proteins.

    Science.gov (United States)

    Li, Sanshu; Smith, Kathryn D; Davis, Jared H; Gordon, Patricia B; Breaker, Ronald R; Strobel, Scott A

    2013-11-19

    Fluorine is an abundant element and is toxic to organisms from bacteria to humans, but the mechanisms by which eukaryotes resist fluoride toxicity are unknown. The Escherichia coli gene crcB was recently shown to be regulated by a fluoride-responsive riboswitch, implicating it in fluoride response. There are >8,000 crcB homologs across all domains of life, indicating that it has an important role in biology. Here we demonstrate that eukaryotic homologs [renamed FEX (fluoride exporter)] function in fluoride export. FEX KOs in three eukaryotic model organisms, Neurospora crassa, Saccharomyces cerevisiae, and Candida albicans, are highly sensitized to fluoride (>200-fold) but not to other halides. Some of these KO strains are unable to grow in fluoride concentrations found in tap water. Using the radioactive isotope of fluoride, (18)F, we developed an assay to measure the intracellular fluoride concentration and show that the FEX deletion strains accumulate fluoride in excess of the external concentration, providing direct evidence of FEX function in fluoride efflux. In addition, they are more sensitive to lower pH in the presence of fluoride. These results demonstrate that eukaryotic FEX genes encode a previously unrecognized class of fluoride exporter necessary for survival in standard environmental conditions.

  8. Confrontation of thermoluminescence models in lithium fluoride with experimental data

    International Nuclear Information System (INIS)

    Niewiadomski, T.

    1976-12-01

    The thermoluminescent properties of lithium fluoride depend on numerous factors and are much more complex than those of other phosphors. The so far developed fragmentary models are meant to explain the relationships between crystal defect structure and the processes involved in TL. An attempt has been made to compare these models with the veryfied experimental data and to point out the observations which are inconsistant with the models. (author)

  9. Electrolytic coloration of air-grown sodium fluoride crystals

    International Nuclear Information System (INIS)

    Gu Hongen; Han Li; Song Cuiying; Guo Meili; Wang Na

    2007-01-01

    Air-grown sodium fluoride crystals were colored electrolytically by using a pointed cathode at various temperatures and electric field strengths, which should mainly benefit appropriate coloration temperatures and electric field strengths. O 2 - , F, M, N 1 , N 2 color centers and O 2- -F + complexes were produced in the colored crystals. Current-time curves for the electrolytic colorations were given, and activation energy for the V color center migration was determined. The formation of the color centers was explained

  10. Molten salts and nuclear energy production

    International Nuclear Information System (INIS)

    Le Brun, Christian

    2007-01-01

    Molten salts (fluorides or chlorides) were considered near the beginning of research into nuclear energy production. This was initially due to their advantageous physical and chemical properties: good heat transfer capacity, radiation insensitivity, high boiling point, wide range solubility for actinides. In addition it was realised that molten salts could be used in numerous situations: high temperature heat transfer, core coolants with solid fuels, liquid fuel in a molten salt reactor, solvents for spent nuclear solid fuel in the case of pyro-reprocessing and coolant and tritium production in the case of fusion. Molten salt reactors, one of the six innovative concepts chosen by the Generation IV international forum, are particularly interesting for use as either waste incinerators or thorium cycle systems. As the neutron balance in the thorium cycle is very tight, the possibility to perform online extraction of some fission product poisons from the salt is very attractive. In this article the most important questions that must be addressed to demonstrate the feasibility of molten salt reactor will be reviewed

  11. SITUATION OF FLUORIDES RATE IN WATERS AND MAJOR CONSUMED FOOD IN WILAYA EL-OUED

    Directory of Open Access Journals (Sweden)

    A. Zobeidi

    2013-12-01

    Full Text Available The effects of mineral salts in the drinking water, beneficial or harmful depending on their concentration, are known for many years and thus the problem posed by fluoride ions in the waters of the region (Fluorosis Dental and skeletal. This study proposes, the estimated daily intake of fluoride from its water distribution and the main food consumed per capita in the region of El-Oued (dates, tea, couscous, lentils, carrots, potatoes, pumpkin ..., which has a significant content of fluoride in their composition. In addition to the arid climatic conditions, the air temperature is very high in summer, leads to a strong human perspiration. This preliminary result leads us to propose a standard fluoride-specific region of El-Oued. The results showed that the majority of water samples and analyzed the main foods of the region of El-Oued is charged fluoride ions and exceed the maximum dose recommended for adults from 0.05 to 0.07 mg / kg / day.

  12. SITUATION OF FLUORIDES RATE IN WATERS AND MAJOR CONSUMED FOOD IN WILAYA EL-OUED

    Directory of Open Access Journals (Sweden)

    A. Zobeidi

    2015-08-01

    Full Text Available The effects of mineral salts in the drinking water, beneficial or harmful depending on their concentration, are known for many years and thus the problem posed                     by fluoride ions in the waters of the region (Fluorosis Dental and skeletal. This                  study proposes, the estimated daily intake of fluoride from its water distribution and           the main food consumed per capita in the region of El-Oued (dates, tea,                          couscous, lentils, carrots, potatoes, pumpkin ..., which has a significant content of fluoride in their composition. In addition to the arid climatic conditions, the air temperature is very high in summer, leads to a strong human perspiration. This preliminary result leads us to propose a standard fluoride-specific region of El-Oued. The results showed that the majority of water samples and analyzed the main foods of the region of El-Oued is charged fluoride ions and exceed the maximum dose recommended for adults from 0.05 to 0.07 mg / kg / day.

  13. Heterogeneous catalysis in fluoride melts - reduction of uranium(V) by hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Kelmers, A D; Bennett, M R [Oak Ridge National Lab., Tenn. (USA)

    1976-01-01

    A necessary step in fuel reprocessing for the Molten-Salt Breeder Reactor is the reduction of pentavalent uranium to tetravalent uranium by hydrogen gas. The pentavalent uranium is dissolved in a mixed fluoride melt. Results are presented which show that the hydrogen reduction is rate limited, possibly due to the dissociation of hydrogen molecules to yield active hydrogen atoms; and that by the application of platinum catalysts a 10- to 100-fold increase in the reaction rate can be achieved.

  14. INORGANIC AND ORGANIC ONIUM SALTS

    Science.gov (United States)

    The nitrosonium NO ion absorbs in the infrared between 1/2400 and 1/ 2150 cm. Salts of complex fluoro-acids absorb at higher frequencies than salts...halide adducts generally contain nitrosonium ions . Hexaphenylditin does not undergo marked heterolytic dissociation in nitromethane solution...influencing the covalent-ionic equilibrium are discussed. Infrared spectrum nitrosonium ion ; ionic character in lattice and position nitrosonium ion absorption

  15. DISSOLUTION OF LANTHANUM FLUORIDE PRECIPITATES

    Science.gov (United States)

    Fries, B.A.

    1959-11-10

    A plutonium separatory ore concentration procedure involving the use of a fluoride type of carrier is presented. An improvement is given in the derivation step in the process for plutonium recovery by carrier precipitation of plutonium values from solution with a lanthanum fluoride carrier precipitate and subsequent derivation from the resulting plutonium bearing carrier precipitate of an aqueous acidic plutonium-containing solution. The carrier precipitate is contacted with a concentrated aqueous solution of potassium carbonate to effect dissolution therein of at least a part of the precipitate, including the plutonium values. Any remaining precipitate is separated from the resulting solution and dissolves in an aqueous solution containing at least 20% by weight of potassium carbonate. The reacting solutions are combined, and an alkali metal hydroxide added to a concentration of at least 2N to precipitate lanthanum hydroxide concomitantly carrying plutonium values.

  16. Groundwater fluoride contamination: A reappraisal

    Directory of Open Access Journals (Sweden)

    Amlan Banerjee

    2015-03-01

    Full Text Available Dissolution of fluorite (CaF2 and/or fluorapatite (FAP [Ca5(PO43F], pulled by calcite precipitation, is thought to be the dominant mechanism responsible for groundwater fluoride (F− contamination. Here, one dimensional reactive–transport models are developed to test this mechanism using the published dissolution and precipitation rate kinetics for the mineral pair FAP and calcite. Simulation results correctly show positive correlation between the aqueous concentrations of F− and CO32− and negative correlation between F− and Ca2+. Results also show that precipitation of calcite, contrary to the present understanding, slows down the FAP dissolution by 106 orders of magnitude compared to the FAP dissolution by hydrolysis. For appreciable amount of fluoride contamination rock–water interaction time must be long and of order 106 years.

  17. Effects of hydrogen fluoride on plants

    Energy Technology Data Exchange (ETDEWEB)

    Yamazoe, F

    1970-07-15

    Symptoms of fluorosis in plants are chlorotic markings around the tip or edges of young leaves. Examples of damage to plants and livestock by fluorides are listed, including the retarded growth of silkworms fed on mulberry leaves polluted by more than 30 ppm fluorides. Plants can be classified into six groups according to their resistance to hydrogen fluoride. Threshold values of the fluoride concentration range from 5-10 ppb for the plants. Gladiolus is normally employed as a plant indicator for hydrogen fluoride and silkworms as indicator insects. The relationship between plant damage by fluorides and exposure time, density, soil, fertilizer, meteorology and location are examined. Several preventive measures are listed, including the spraying of water or lime on plant leaves. It is concluded that the establishment of an environmental standard is difficult because of the extremely high sensitivity of the plants to the gas. 8 references.

  18. Thermodynamic data for uranium fluorides

    International Nuclear Information System (INIS)

    Leitnaker, J.M.

    1983-03-01

    Self-consistent thermodynamic data have been tabulated for uranium fluorides between UF 4 and UF 6 , including UF 4 (solid and gas), U 4 F 17 (solid), U 2 F 9 (solid), UF 5 (solid and gas), U 2 F 10 (gas), and UF 6 (solid, liquid, and gas). Included are thermal function - the heat capacity, enthalpy, and free energy function, heats of formation, and vaporization behavior

  19. Investigation of interaction of zirconium and hafnium tetrafluorides with strontium fluoride

    International Nuclear Information System (INIS)

    Ratnikova, I.D.; Korenev, Yu.M.; Novoselova, A.V.

    1980-01-01

    Diagrams of the condensated state of systems SrF 2 -EF 4 have been plotted, where E represents Zr, Hf. In these systems, three intermediate compounds of Sr 3 EF 10 , Sr 2 EF 8 and Sr EF 6 compositions are formed. All those compounds melt incongruently at temperatures of 982, 865 and 750 deg C, respectively - zirconium salt; at temperatures of 1000, 900 and 820 deg C - hafnium salts. Fluoro-metallates of composition 2:1, and 1:1, exist in two polymorphic forms. Tetrafluorides were found to dissolve in strontium fluoride: they form solid solutions having fluorite structure

  20. Fluoride removal from aqueous solution by pumice: case study on ...

    African Journals Online (AJOL)

    EJIRO

    conditions, the fluoride removal efficiency from Kuhbonan water by 2.8 mg/L fluoride was 74.64%. Eventually ... industrial wastewater containing fluoride is a key ..... solution using silica ceramic: Adsorption kinetics and equilibrium studies.

  1. Ferromagnetic behavior in linear charge-transfer complexes. Structural and magnetic characterization of octamethylferrocene salts: (Fe(C sub 5 Me sub 4 H) sub 2 ) sup sm bullet + (A) sup sm bullet minus (A = TCNE, TCNQ)

    Energy Technology Data Exchange (ETDEWEB)

    Miller, J.S.; Glatzhofer, D.T.; O' Hare, D.M. (E.I. de Pont de Nemours and Co., Inc., Wilmington, DE (USA)); Reiff, W.M. (Northeastern Univ., Boston, MA (USA)); Chakraborty, A.; Epstein, A.J. (Ohio Sate Univ., Columbus (USA))

    1989-07-26

    The reaction of Fe{sup II}({eta}{sup 5}-C{sub 5}Me{sub 4}H){sub 2} with cyano acceptors A (A = TCNE (tetracyanoethylene), TCNQ (7,7,8,8-tetracyano-p-quanodimethane), n-C{sub 4}(CN){sub 6} (n-hexacyanobutadiene), C{sub 6}(CN){sub 6} (tris(dicyanomethylene)cyclopropane), DDQ (2,3-dichloro-5,6-dicyanobenzoquinone), TCNQF{sub 4} (perfluoro-7,7,8,8-tetracyano-p-quinodimethane) results in formation of 1:1 charge-transfer salts of (Fe{sup III})(C{sub 5}Me{sub 4}H){sub 2}){sup {sm bullet}+}(A){sup {sm bullet}{minus}} composition. The TCNE and TCNQ complexes have been structurally characterized. The high-temperature magnetic susceptibility for polycrystalline samples of these complexes can be fit by the Curie-Qeiss law, {chi} = C(T-{theta}){sup {minus}1}, with {theta} = +0.5 {plus minus} 2.2 K, and {mu}{sub eff} ranges from 2.71 to 3.97 {mu}{sub B}, suggesting that the polycrystalline samples measured had varying degrees of orientation. The 7.0 K EPR spectrum of the radical cation exhibits an axially symmetric powder pattern with g{sub {parallel}} = 4.11 and g{sub {perpendicular}} = 1.42, and the EPR parameters are essentially identical with those reported for ferrocenium and decamethylferrocenium. No EPR spectrum is observed at 78 K. Akin to the (Fe(C{sub 5}Me{sub 5}){sub 2}){sup {sm bullet}+} salts, these salts have {sup 57}Fe Moessbauer spectra consistent with complete charge transfer; however, unlike the case for the former complexes, quadrupole splittings of 0.30 and 0.220 mm/s are observed at 4.8 and 298 K, respectively. The absence of strong interionic magnetic coupling for the (Fe(C{sub 5}Me{sub 4}H){sub 2}){sup {sm bullet}+} salts contrasts with the behavior of the (Fe(C{sub 5}Me{sub 5}){sub 2}){sup {sm bullet}+} salts. 26 refs., 13 figs., 8 tabs.

  2. Purification process of uranium hexafluoride containing traces of plutonium fluoride and/or neptunium fluoride

    International Nuclear Information System (INIS)

    Aubert, J.; Bethuel, L.; Carles, M.

    1983-01-01

    In this process impure uranium hexafluoride is contacted with a metallic fluoride chosen in the group containing lead fluoride PbF 2 , uranium fluorides UFsub(4+x) (0 3 at a temperature such as plutonium and/or neptunium are reduced and pure uranium hexafluoride is recovered. Application is made to uranium hexafluoride purification in spent fuel reprocessing [fr

  3. Fluoride ions vs removal technologies: A study

    OpenAIRE

    Singh, Jagvir; Singh, Prashant; Singh, Anuradha

    2016-01-01

    Literature reported that drinking water is a precious and scarce resource and it has to be protected and kept free from any kind of contamination. Further, it has to be used carefully without wasting. Literature also reported that fluoride bearing rocks are abundant in India, as a result, fluoride leaches out and contaminates the adjacent water and soil resources. A high concentration of fluoride ions in ground water increases up to more than 30 mg/L. This high concentration of fluoride ions ...

  4. Gramicidin D enhances the antibacterial activity of fluoride

    OpenAIRE

    Nelson, James W.; Zhou, Zhiyuan; Breaker, Ronald R.

    2014-01-01

    Fluoride is a toxic anion found in many natural environments. One of the major bacterial defenses against fluoride is the cell envelope, which limits passage of the membrane-impermeant fluoride anion. Accordingly, compounds that enhance the permeability of bacterial membranes to fluoride should also enhance fluoride toxicity. In this study, we demonstrate that the pore-forming antibiotic gramicidin D increases fluoride uptake in B. subtilis and that the antibacterial activity of this compound...

  5. Urinary fluoride output in children following the use of a dual-fluoride varnish formulation

    Directory of Open Access Journals (Sweden)

    Kelly Polido Kaneshiro Olympio

    2009-06-01

    Full Text Available OBJECTIVE: This study evaluated the bioavailability of fluoride after topical application of a dual-fluoride varnish commercially available in Brazil, when compared to DuraphatTM. MATERIAL AND METHODS: The urinary fluoride output was evaluated in seven 5-year-old children after application of the fluoride varnishes, in two different phases. In the first phase (I, children received topical application of the fluoride varnish Duofluorid XII (2.92% fluorine, calcium fluoride + 2.71% fluorine, sodium fluoride, FGM TM. After 1-month interval (phase II, the same amount (0.2 mL of the fluoride varnish Duraphat (2.26% fluorine, sodium fluoride, ColgateTM was applied. Before each application all the volunteers brushed their teeth with placebo dentifrice for 7 days. Urinary collections were carried out 24 h prior up to 48 h after the applications. Fluoride intake from the diet was also estimated. Fluoride concentration in diet samples and urine was analyzed with the fluoride ion-specific electrode and a miniature calomel reference electrode coupled to a potentiometer. Data were tested by ANOVA and Tukey's post hoc test (p<0.05. RESULTS: There were significant differences in the urinary fluoride output between phases I and II. The use of Duofluorid XII did not significantly increase the urinary fluoride output, when compared to baseline levels. The application of Duraphat caused a transitory increase in the urinary fluoride output, returning to baseline levels 48 h after its use. CONCLUSIONS: The tested varnish formulation, which has been shown to be effective in in vitro studies, also can be considered safe.

  6. Fluoride barriers in Nb/Pb Josephson junctions

    Science.gov (United States)

    Asano, H.; Tanabe, K.; Michikami, O.; Igarashi, M.; Beasley, M. R.

    1985-03-01

    Josephson tunnel junctions are fabricated using a new class of artificial barriers, metal fluorides (Al fluoride and Zr fluoride). These fluoride barriers are deposited on the surface of a Nb base electrode, which are previously cleaned using a CF4 cleaning process, and covered by a Pb counterelectrode. The junctions with both Al fluoride and Zr fluoride barriers exhibit good tunneling characteristics and have low specific capacitance. In the case of Zr fluoride, it is observed that reasonable resistances are obtained even at thickness greater than 100 A. This phenomenon might be explained by tunneling via localized states in Zr fluoride.

  7. Method of converting uranium fluoride to intermediate product for uranium oxide manufacture with recycling or reusing valuable materials

    International Nuclear Information System (INIS)

    Baran, V.; Moltasova, J.

    1982-01-01

    Uranium fluoride is acted upon by water with nitrate containing a cation capable of binding fluoride ions. The uranium is extracted, for instance, with tributyl phosphate with the generated organic phase containing the prevalent proportion of uranium and representing the required intermediate product and the aqueous phase from which is isolated the fluorine component which may be used within the fuel cycle. The nitrate component of the aqueous phase is recycled following treatment. It is also possible to act on uranium fluoride directly with an aqueous solution. Here the cations of nitrate form with the fluorides soluble nondissociated complexes and reduce the concentration of free fluoride ions. The nitrate +s mostly used in an amount corresponding to its solubility in the system prior to the introduction of UF 6 . The uranium from the solution with the reduced concentration of free fluoride ions is extracted into the reaction system under such conditions as to make the prevalent majority of fluorides and an amount of uranium smaller than 5x10 -2 mol/l remain in the aqueous phase and that such an amount of fluorides should remain in the organic phase which is smaller than corresponds to the fluorine/uranium molar ratio in the organic phase. Uranium contained in the organic phase is processed into uranium oxide, with advantage into UO 2 . From the isolated compounds of fluorine and the cation of the nitrate gaseous HF is released which is used either inside or outside of the fuel cycle. (J.P.)

  8. Complete Sensitivity/Uncertainty Analysis of LR-0 Reactor Experiments with MSRE FLiBe Salt and Perform Comparison with Molten Salt Cooled and Molten Salt Fueled Reactor Models

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Nicholas R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Powers, Jeffrey J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Mueller, Don [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Patton, Bruce W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-12-01

    In September 2016, reactor physics measurements were conducted at Research Centre Rez (RC Rez) using the FLiBe (2 7LiF + BeF2) salt from the Molten Salt Reactor Experiment (MSRE) in the LR-0 low power nuclear reactor. These experiments were intended to inform on neutron spectral effects and nuclear data uncertainties for advanced reactor systems using FLiBe salt in a thermal neutron energy spectrum. Oak Ridge National Laboratory (ORNL), in collaboration with RC Rez, performed sensitivity/uncertainty (S/U) analyses of these experiments as part of the ongoing collaboration between the United States and the Czech Republic on civilian nuclear energy research and development. The objectives of these analyses were (1) to identify potential sources of bias in fluoride salt-cooled and salt-fueled reactor simulations resulting from cross section uncertainties, and (2) to produce the sensitivity of neutron multiplication to cross section data on an energy-dependent basis for specific nuclides. This report provides a final report on the S/U analyses of critical experiments at the LR-0 Reactor relevant to fluoride salt-cooled high temperature reactor (FHR) and liquid-fueled molten salt reactor (MSR) concepts. In the future, these S/U analyses could be used to inform the design of additional FLiBe-based experiments using the salt from MSRE. The key finding of this work is that, for both solid and liquid fueled fluoride salt reactors, radiative capture in 7Li is the most significant contributor to potential bias in neutronics calculations within the FLiBe salt.

  9. Inventories and mobilization of unsaturated zone sulfate, fluoride, and chloride related to land use change in semiarid regions, southwestern United States and Australia

    Science.gov (United States)

    Scanlon, Bridget R.; Stonestrom, David A.; Reedy, Robert C.; Leaney, Fred W.; Gates, John; Cresswell, Richard G.

    2009-01-01

    Unsaturated zone salt reservoirs are potentially mobilized by increased groundwater recharge as semiarid lands are cultivated. This study explores the amounts of pore water sulfate and fluoride relative to chloride in unsaturated zone profiles, evaluates their sources, estimates mobilization due to past land use change, and assesses the impacts on groundwater quality. Inventories of water‐extractable chloride, sulfate, and fluoride were determined from borehole samples of soils and sediments collected beneath natural ecosystems (N = 4), nonirrigated (“rain‐fed”) croplands (N = 18), and irrigated croplands (N = 6) in the southwestern United States and in the Murray Basin, Australia. Natural ecosystems contain generally large sulfate inventories (7800–120,000 kg/ha) and lower fluoride inventories (630–3900 kg/ha) relative to chloride inventories (6600–41,000 kg/ha). Order‐of‐magnitude higher chloride concentrations in precipitation and generally longer accumulation times result in much larger chloride inventories in the Murray Basin than in the southwestern United States. Atmospheric deposition during the current dry interglacial climatic regime accounts for most of the measured sulfate in both U.S. and Australian regions. Fluoride inventories are greater than can be accounted for by atmospheric deposition in most cases, suggesting that fluoride may accumulate across glacial/interglacial climatic cycles. Chemical modeling indicates that fluorite controls fluoride mobility and suggests that water‐extractable fluoride may include some fluoride from mineral dissolution. Increased groundwater drainage/recharge following land use change readily mobilized chloride. Sulfate displacement fronts matched or lagged chloride fronts by up to 4 m. In contrast, fluoride mobilization was minimal in all regions. Understanding linkages between salt inventories, increased recharge, and groundwater quality is important for quantifying impacts of anthropogenic

  10. Controllable solvothermal synthesis and photocatalytic properties of complex (oxy)fluorides K{sub 2}TiOF{sub 4}, K{sub 3}TiOF{sub 5}, K{sub 7}Ti{sub 4}O{sub 4}F{sub 7} and K{sub 2}TiF{sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Sheng Jie [Division of Nanomaterials and Nanochemistry, Hefei National Laboratory for Physical Sciences at Microscale, Hefei, Anhui 230026 (China); Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026 (China); Tang Kaibin, E-mail: kbtang@ustc.edu.cn [Division of Nanomaterials and Nanochemistry, Hefei National Laboratory for Physical Sciences at Microscale, Hefei, Anhui 230026 (China); Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026 (China); Cheng Wei; Wang Junli; Nie Yanxiang; Yang Qing [Division of Nanomaterials and Nanochemistry, Hefei National Laboratory for Physical Sciences at Microscale, Hefei, Anhui 230026 (China); Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2009-11-15

    Complex (oxy)fluorides K{sub 2}TiF{sub 6}, K{sub 2}TiOF{sub 4}, K{sub 3}TiOF{sub 5} and K{sub 7}Ti{sub 4}O{sub 4}F{sub 7} have been successfully synthesized for the first time through a controllable solvothermal route involving different solvents, for example, methanol, methanol-H{sub 2}O and methanol-H{sub 2}O{sub 2}. The as-prepared products were characterized by X-ray powder diffraction, N{sub 2} surface area adsorption, scanning electron microscope, Fourier transform infrared spectroscopy, UV-vis absorption spectra and X-ray fluorescence. The influences of reaction conditions such as the ratio of methanol to H{sub 2}O{sub 2} or methanol to H{sub 2}O, reaction temperature on the phase, crystallizability and purity of the (oxy)fluorides products were discussed in detail. Meanwhile, the photocatalytic behaviors of the as-prepared K{sub 2}TiF{sub 6}, K{sub 2}TiOF{sub 4}, K{sub 3}TiOF{sub 5} and K{sub 7}Ti{sub 4}O{sub 4}F{sub 7} were evaluated by degradation of rhodamine B molecules, and the results showed that all of the products possessed photocatalytic activities in the order of K{sub 2}TiOF{sub 4} > K{sub 2}TiF{sub 6} > K{sub 7}Ti{sub 4}O{sub 4}F{sub 7} > K{sub 3}TiOF{sub 5} at room temperature under the UV light.

  11. The in vitro effect of fluoridated milk in a bacterial biofilm--enamel model.

    Science.gov (United States)

    Arnold, Wolfgang H; Forer, Stefan; Heesen, Joerg; Yudovich, Keren; Steinberg, Doron; Gaengler, Peter

    2006-07-01

    The purpose of this study was to investigate the effect of milk and fluoridated milk on bacterially induced caries-like lesions. Extracted impacted human molars were cut in half and covered with a varnish leaving a 4*4 mm window. The samples were coated with biofilm of S. sobrinus and were further divided into three experimental groups of S. sobrinus, S. sobrinus and milk and S. sobrinus and fluoridated milk. As negative controls served teeth incubated in saline. Of twenty tooth halves serial ground sections were cut through the lesions and investigated with polarization light microscopy (PLM) and scanning electron microscopy (SEM) and EDX element analysis. The PLM photographs were used for 3D reconstruction, volumetric assessment and determination of the extension of the lesion zones. Of eight tooth halves the biofilm on the enamel surface was studied with SEM and EDX element analysis. Volumetric assessment showed a statistically significant difference in the volume of the body of the lesion and the translucent zone between the milk group and fluoridated milk group. Quantitative element analysis demonstrated significant differences between sound enamel and the superficial layer in the fluoridated milk group. The biofilm on the enamel surface showed an increased Ca content in the milk group and fluoridated milk group. Milk as a common nutrient seems to play a complex role in in-vitro biofilm--enamel interactions stimulating bacterial demineralization on one hand, and, as effective fluoride carrier, inhibits caries-like demineralization.

  12. FLUORIDE LEVELS IN COMMERCIALLY AVAILABLE RICE IN ...

    African Journals Online (AJOL)

    Preferred Customer

    2013-05-05

    May 5, 2013 ... Rice is one of the commonly consumed cereals for more than half of the ... also used as flour, for making rice wine, as ingredient for beer and liquor, ... Fluoride is a necessary element to human health, and a moderate amount of fluoride intake ... For Ethiopian red rice (ERR) Fogera was selected to collect.

  13. Biomonitoring Equivalents for interpretation of urinary fluoride.

    Science.gov (United States)

    Aylward, L L; Hays, S M; Vezina, A; Deveau, M; St-Amand, A; Nong, A

    2015-06-01

    Exposure to fluoride is widespread due to its natural occurrence in the environment and addition to drinking water and dental products for the prevention of dental caries. The potential health risks of excess fluoride exposure include aesthetically unacceptable dental fluorosis (tooth mottling) and increased skeletal fragility. Numerous organizations have conducted risk assessments and set guidance values to represent maximum recommended exposure levels as well as recommended adequate intake levels based on potential public health benefits of fluoride exposure. Biomonitoring Equivalents (BEs) are estimates of the average biomarker concentrations corresponding to such exposure guidance values. The literature on daily urinary fluoride excretion rates as a function of daily fluoride exposure was reviewed and BE values corresponding to the available US and Canadian exposure guidance values were derived for fluoride in urine. The derived BE values range from 1.1 to 2.1mg/L (1.2-2.5μg/g creatinine). Concentrations of fluoride in single urinary spot samples from individuals, even under exposure conditions consistent with the exposure guidance values, may vary from the predicted average concentrations by several-fold due to within- and across-individual variation in urinary flow and creatinine excretion rates and due to the rapid elimination kinetics of fluoride. Thus, the BE values are most appropriately applied to screen population central tendency estimates for biomarker concentrations rather than interpretation of individual spot sample concentrations. Copyright © 2015. Published by Elsevier Inc.

  14. Fluoride ions vs removal technologies: A study

    Directory of Open Access Journals (Sweden)

    Jagvir Singh

    2016-11-01

    Full Text Available Literature reported that drinking water is a precious and scarce resource and it has to be protected and kept free from any kind of contamination. Further, it has to be used carefully without wasting. Literature also reported that fluoride bearing rocks are abundant in India, as a result, fluoride leaches out and contaminates the adjacent water and soil resources. A high concentration of fluoride ions in ground water increases up to more than 30 mg/L. This high concentration of fluoride ions causes many harmful and dangerous effects on our datum. Fluoride ions in larger quantities i.e. 20–80 mg/day taken over a period of 10–20 years result in crippling and skeletal fluorosis, severely damaging the bone. In the present scenario, there is a continuously increasing worldwide concern for the development of fluoride treatment technologies. Possibilities of reducing the high fluorine content in groundwater are by defluorination process/dilution with the surface water which is a very simple technique but the addition of Ca2+ ions to a solution in contact with fluorite when experimented in distilled water caused an appreciable decrease in fluoride concentration. In this review article, we emphasized the relationship between high concentrations of fluoride ions and their compounds and their health impact.

  15. The effect of fluoride on the scavenging of organophosphates by human butyrylcholinesterase in buffer solutions and human plasma

    International Nuclear Information System (INIS)

    Ashani, Yacov; Segev, Omri; Balan, Ayala

    2004-01-01

    Fluoride ion is a reversible inhibitor of human butyrylcholinesterase (HuBChE) that is a viable drug candidate against organophosphates (OPs) toxicity. Since large numbers of communities in many countries are occasionally exposed to relatively high amount of fluoride, its effect on the kinetics of inhibition of HuBChE by OPs was investigated. In saline phosphate, pH 7.4, fluoride in the lower millimolar range significantly slowed the inhibition of HuBChE by paraoxon, DFP, echothiophate, soman, sarin, and VX. The kinetics of the inhibition was found consistent with the formation of a reversible fluoride-HuBChE complex that is at least 25-fold less active towards phosphorylation or phosphonylation than the free enzyme. Heat inactivation experiments indicate that the binding of fluoride to HuBChE probably involves enhanced cross-domain interaction via hydrogen bonds formation that may decrease enzyme activity. In spite of distinct structural differences among the OP used, the dissociation constants of the fluoride-HuBChE reversible complex varied over a narrow range (K F , 0.31-0.70 mM); however, K F in human plasma increased to 2.75-3.40 mM. 19 F-NMR spectroscopy revealed that fluoride ion is complexed to plasma components, an observation that explains in part the apparent increase in K F . Results suggest that an estimate of the relative decrease in the rate of OPs sequestration in presence of fluoride can be obtained from the fraction of the free HuBChE (1 + [F]/K F ) -1 . Considering K F values in human plasma, it is concluded that the scavenging efficacy of OPs by HuBChE is not compromised by the normal concentration range of circulating fluoride ions

  16. Diethylenetriaminium hexafluoridotitanate(IV fluoride

    Directory of Open Access Journals (Sweden)

    J. Lhoste

    2008-11-01

    Full Text Available The title compound, (C6H21N4[TiF6]F, was synthesized by the reaction of TiO2, tris(2-aminoethylamine, HF and ethanol at 463 K in a microwave oven. The crystal structure consists of two crystallographically independent [TiF6]2− anions, two fluoride anions and two triply-protonated tris(2-aminoethylamine cations. The Ti atoms are coordinated by six F atoms within slightly distorted octahedra. The anions and cations are connected by intermolecular N—H...F hydrogen bonds.

  17. Thermodynamic data for uranium fluorides

    Energy Technology Data Exchange (ETDEWEB)

    Leitnaker, J.M.

    1983-03-01

    Self-consistent thermodynamic data have been tabulated for uranium fluorides between UF/sub 4/ and UF/sub 6/, including UF/sub 4/ (solid and gas), U/sub 4/F/sub 17/ (solid), U/sub 2/F/sub 9/ (solid), UF/sub 5/ (solid and gas), U/sub 2/F/sub 10/ (gas), and UF/sub 6/ (solid, liquid, and gas). Included are thermal function - the heat capacity, enthalpy, and free energy function, heats of formation, and vaporization behavior.

  18. Niobium electrodeposition from molten fluorides

    International Nuclear Information System (INIS)

    Sartori, A.F.

    1987-01-01

    Niobium electrodeposition from molten alkali fluorides has been studied aiming the application of this technic to the processes of electrorefining and galvanotechnic of this metal. The effects of current density, temperature, niobium concentration in the bath, electrolysis time, substrate nature, ratio between anodic and cathodic areas, electrodes separation and the purity of anodes were investigated in relation to the cathodic current efficiency, electrorefining, electroplating and properties of the deposit and the electrolytic solution. The work also gives the results of the conctruction and operation of a pilot plant for refractory metals electrodeposition and shows the electrorefining and electroplating compared to those obtained at the laboratory scale. (author) [pt

  19. Measurement of fluoride in bone

    International Nuclear Information System (INIS)

    Mernagh, J.R.; Harrision, J.E.; Hancock, R.; McNeill, K.G.

    1977-01-01

    The fluorine concentration in bone biopsy samples was measured by neutron activation analysis. The fluorine content was expressed in terms of the calcium content. Samples were irradiated in a reactor to induce the 19 F(n,γ) 20 F and 48 Ca(n,γ) 49 Ca reactions and after rapid transport from the reactor the resulting activities were measured with a Ge(Li) detector. Reproducibility was better than 10% for the F/Ca ratio. The detection limit for F is 50 μg. This nondestructive technique will be used to assess the effect of fluoride therapy on bone metabolism of patients with idiopathic osteoporosis. (author)

  20. Determination of Fluoride in Different Toothpaste Formulations

    International Nuclear Information System (INIS)

    Kamau, N.G.; Njoroge, M.; Njau, M.

    1998-01-01

    Fluoride ion selective electrode was used to determine fluoride ion concentrations in seven brands of toothpaste. These were the only available formulations found in Kenya. The brands were classified into three groups-fluoridated, non fluoridated or not indicated. However, there was no independent indication of their quantitative composition. The analysed brands had fluoride content between 0.0033% and 0.096%. These values compared favourably with those obtained elsewhere. The calculated lowest limit of detection (LLD) was 0.01 ppmF- . The mean calibration curve gave a slope of of -50.0mV. which was not significantly different from the theoretical value of 5.88mV at 23 degrees celsius at 95% confidence level

  1. Environmental evaluation of fluoride in drinking water at "Los Altos de Jalisco," in the central Mexico region.

    Science.gov (United States)

    Hurtado, Roberto; Gardea-Torresdey, Jorge

    Naturally occurring fluoride has been detected and quantified in drinking water in several cities of the "Los Altos de Jalisco" (LAJ) region. LAJ is located in the northeastern part of the state of Jalisco-Mexico, covering an area of 16,410 km2 with a population of 696,318 in 20 municipalities. Drinking water comes mainly from groundwater aquifers, located in the Trans-Mexican Volcanic Belt, which is a volcanic region characterized by hydrothermal activity. Results indicated that water supply from 42% of the municipalities had a fluoride concentration over the Mexican standards of 1.5 mg/L. It is important to notice that there are three cities, Lagos de Moreno (1.66-5.88 mg/L F(-)), Teocaltiche (3.82-18.58 mg/L F(-)), and Encarnación de Díaz (2.58-4.40 mg/L F(-)) where all water samples resulted in fluoride concentration over the maximum contaminant level. The total population from these three cities is over 122,000 inhabitants. Another important city with high levels of fluoride in the water supply was Tepatitlán de Morelos (2 wells with 6.54 and 13.47 mg/L F(-)). In addition to water supply, 30 samples of brand-name bottled water were tested. Surprisingly, 8 samples (27%) demonstrated fluoride level over the standards, mainly Agua de Lagos with 5.27 mg/L. Fluoridated table salt (200-300 mg/kg F(-)) is another important source of fluoride. A large number of people living in the region, mainly school children, might be under adverse health risk because they are consuming contaminated drinking water. It is well known that long-term exposure to water with high levels of fluoride produces severe health problems.

  2. Corrosion behavior of zirconia in acidulated phosphate fluoride

    Directory of Open Access Journals (Sweden)

    Anie Thomas

    2016-02-01

    Full Text Available ABSTRACT Objective The corrosion behavior of zirconia in acidulated phosphate fluoride (APF representing acidic environments and fluoride treatments was studied. Material and Methods Zirconia rods were immersed in 1.23% and 0.123% APF solutions and maintained at 37°C for determined periods of time. Surfaces of all specimens were imaged using digital microscopy and scanning electron microscopy (SEM. Sample mass and dimensions were measured for mass loss determination. Samples were characterized by powder X-ray diffraction (XRD to detect changes in crystallinity. A biosensor based on electrochemical impedance spectroscopy (EIS was used to detect ion dissolution of material into the immersion media. Results Digital microscopy revealed diminishing luster of the materials and SEM showed increased superficial corrosion of zirconia submerged in 1.23% APF. Although no structural change was found, the absorption of salts (sodium phosphate onto the surface of the materials bathed in 0.123% APF was significant. EIS indicated a greater change of impedance for the immersion solutions with increasing bathing time. Conclusion Immersion of zirconia in APF solutions showed deterioration limited to the surface, not extending to the bulk of the material. Inferences on zirconia performance in acidic oral environment can be elucidated from the study.

  3. Fast molten salt reactor-transmuter for closing nuclear fuel cycle on minor actinides

    International Nuclear Information System (INIS)

    Dudnikov, A. A.; Alekseev, P. N.; Subbotin, S. A.

    2007-01-01

    Creation fast critical molten salt reactor for burning-out minor actinides and separate long-living fission products in the closed nuclear fuel cycle is the most perspective and actual direction. The reactor on melts salts - molten salt homogeneous reactor with the circulating fuel, working as burner and transmuter long-living radioactive nuclides in closed nuclear fuel cycle, can serve as an effective ecological cordon from contamination of the nature long-living radiotoxic nuclides. High-flux fast critical molten-salt nuclear reactors in structure of the closed nuclear fuel cycle of the future nuclear power can effectively burning-out / transmute dangerous long-living radioactive nuclides, make radioisotopes, partially utilize plutonium and produce thermal and electric energy. Such reactor allows solving the problems constraining development of large-scale nuclear power, including fueling, minimization of radioactive waste and non-proliferation. Burning minor actinides in molten salt reactor is capable to facilitate work solid fuel power reactors in system NP with the closed nuclear fuel cycle and to reduce transient losses at processing and fabrications fuel pins. At substantiation MSR-transmuter/burner as solvents fuel nuclides for molten-salt reactors various salts were examined, for example: LiF - BeF2; NaF - LiF - BeF2; NaF-LiF ; NaF-ZrF4 ; LiF-NaF -KF; NaCl. RRC 'Kurchatov institute' together with other employees have developed the basic design reactor installations with molten salt reactor - burner long-living nuclides for fluoride fuel composition with the limited solubility minor actinides (MAF3 10 mol %) allows to develop in some times more effective molten salt reactor with fast neutron spectrum - burner/ transmuter of the long-living radioactive waste. In high-flux fast reactors on melts salts within a year it is possible to burn ∼300 kg minor actinides per 1 GW thermal power of reactor. The technical and economic estimation given power

  4. Tritium control and capture in salt-cooled fission and fusion reactors: Status, challenges, and path forward

    International Nuclear Information System (INIS)

    Forsberg, Charles W.; Lam, Stephen; Carpenter, David M.; Whyte, Dennis G.; Scarlat, Raluca

    2017-01-01

    Three advanced nuclear power systems use liquid salt coolants that generate tritium and thus face the common challenges of containing and capturing tritium to prevent its release to the environment. The Fluoride-salt-cooled High-temperature Reactor (FHR) uses clean fluoride salt coolants and the same graphite-matrix coated-particle fuel as high-temperature gas-cooled reactors. Molten salt reactors (MSRs) dissolve the fuel in a fluoride or chloride salt with release of fission product tritium into the salt. In most FHR and MSR systems, the base-line salts contain lithium where isotopically separated "7Li is proposed to minimize tritium production from neutron interactions with the salt. The Chinese Academy of Science plans to start operation of a 2-MWt molten salt test reactor by 2020. For high-magnetic-field fusion machines, the use of lithium enriched in "6Li is proposed to maximize tritium generation the fuel for a fusion machine. Advances in superconductors that enable higher power densities may require the use of molten lithium salts for fusion blankets and as coolants. Recent technical advances in these three reactor classes have resulted in increased government and private interest and the beginning of a coordinated effort to address the tritium control challenges in 700 °C liquid salt systems. We describe characteristics of salt-cooled fission and fusion machines, the basis for growing interest in these technologies, tritium generation in molten salts, the environment for tritium capture, models for high-temperature tritium transport in salt systems, alternative strategies for tritium control, and ongoing experimental work. Several methods to control tritium appear viable. Finally, limited experimental data is the primary constraint for designing efficient cost-effective methods of tritium control.

  5. Study of electrochemical processes for separation of the actinides and lanthanides in molten fluoride media

    International Nuclear Information System (INIS)

    Zvejskova, R.; Chuchvalcova Bimova, K.; Lisy, F.; Soucek, P.

    2005-01-01

    The technology of the Molten Salt Reactors (MSR) is developed for two possible applications: For one thing as the Molten Salt Transmutation Reactor (MSTR) incinerating plutonium and minor actinides within reprocessing of spent fuel from PWR or FBR and for another thing as electricity generating MSR working under thorium uranium fuel cycle. Electrochemical separation processes are one of promising pyrochemical techniques that should enable the on-line reprocessing of circulating fuel salt in MSR (fuel cycle back-end). The former application represents the Czech P and T concept, in which framework the electrolytic separation can be applied both in the front-end and back-end of the MSTR fuel cycle. Within the front-end electro separation should follow the Fluoride Volatility Method (FVM), which should separate 95 % of uranium from the spent fuel in the form of volatile uranium hexafluoride. The residual uranium and fission products (FP) are supposed to be separated among others also by electrochemical methods. The presented work comprises the results reached within development of electrochemical separation of the actinides and fission products from each other by electrolytic deposition method on solid cathode in molten fluoride media, that represent he carrier salts of MSR technology. The knowledge of electrochemical properties (red-ox potentials, mainly of deposition potentials) is necessary for determination of separation possibilities of individual components by electrolysis. (authors)

  6. Cooking without salt

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000760.htm Cooking without salt To use the sharing features on ... other dishes to add zest. Try Salt-free Cooking Explore cooking with salt substitutes. Add a splash ...

  7. Heat Transfer Salts for Nuclear Reactor Systems - Chemistry Control, Corrosion Mitigation, and Modeling

    International Nuclear Information System (INIS)

    Anderson, Mark; Sridharan, Kumar; Morgan, Dane; Peterson, Per; Calderoni, Pattrick; Scheele, Randall; Casekka, Andrew; McNamara, Bruce

    2015-01-01

    The concept of a molten salt reactor has existed for nearly sixty years. Previously all work was done during a large collaborative effort at Oak Ridge National Laboratory, culminating in a research reactor which operated for 15,000 hours without major error. This technical success has garnished interest in modern, high temperature, reactor schemes. Research using molten fluoride salts for nuclear applications requires a steady supply of high grade molten salts. There is no bulk supplier of research grade fluoride salts in the world, so a facility which could provide all the salt needed for testing at the University of Wisconsin had to be produced. Two salt purification devices were made for this purpose, a large scale purifier, and a small scale purifier, each designed to clean the salts from impurities and reduce their corrosion potential. As of now, the small scale has performed with flibe salt, hydrogen, and hydrogen fluoride, yielding clean salt. This salt is currently being used in corrosion testing facilities at the Massachusetts Institute of Technology and the University of Wisconsin. Working with the beryllium based salts requires extensive safety measures and health monitoring to prevent the development of acute or chronic beryllium disease, two pulmonary diseases created by an allergic reaction to beryllium in the lungs. Extensive health monitoring, engineering controls, and environment monitoring had to be set up with the University of Wisconsin department of Environment, Health and Safety. The hydrogen fluoride required for purification was also an extreme health hazard requiring thoughtful planning and execution. These dangers have made research a slow and tedious process. Simple processes, such as chemical handling and clean-up, can take large amounts of ingenuity and time. Other work has complemented the experimental research at Wisconsin to advance high temperature reactor goals. Modeling work has been performed in house to re

  8. Heat Transfer Salts for Nuclear Reactor Systems - Chemistry Control, Corrosion Mitigation, and Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Mark [Univ. of Wisconsin, Madison, WI (United States); Sridharan, Kumar [Univ. of Wisconsin, Madison, WI (United States); Morgan, Dane [Univ. of Wisconsin, Madison, WI (United States); Peterson, Per [Univ. of Wisconsin, Madison, WI (United States); Calderoni, Pattrick [Univ. of Wisconsin, Madison, WI (United States); Scheele, Randall [Univ. of Wisconsin, Madison, WI (United States); Casekka, Andrew [Univ. of Wisconsin, Madison, WI (United States); McNamara, Bruce [Univ. of Wisconsin, Madison, WI (United States)

    2015-01-22

    The concept of a molten salt reactor has existed for nearly sixty years. Previously all work was done during a large collaborative effort at Oak Ridge National Laboratory, culminating in a research reactor which operated for 15,000 hours without major error. This technical success has garnished interest in modern, high temperature, reactor schemes. Research using molten fluoride salts for nuclear applications requires a steady supply of high grade molten salts. There is no bulk supplier of research grade fluoride salts in the world, so a facility which could provide all the salt needed for testing at the University of Wisconsin had to be produced. Two salt purification devices were made for this purpose, a large scale purifier, and a small scale purifier, each designed to clean the salts from impurities and reduce their corrosion potential. As of now, the small scale has performed with flibe salt, hydrogen, and hydrogen fluoride, yielding clean salt. This salt is currently being used in corrosion testing facilities at the Massachusetts Institute of Technology and the University of Wisconsin. Working with the beryllium based salts requires extensive safety measures and health monitoring to prevent the development of acute or chronic beryllium disease, two pulmonary diseases created by an allergic reaction to beryllium in the lungs. Extensive health monitoring, engineering controls, and environment monitoring had to be set up with the University of Wisconsin department of Environment, Health and Safety. The hydrogen fluoride required for purification was also an extreme health hazard requiring thoughtful planning and execution. These dangers have made research a slow and tedious process. Simple processes, such as chemical handling and clean-up, can take large amounts of ingenuity and time. Other work has complemented the experimental research at Wisconsin to advance high temperature reactor goals. Modeling work has been performed in house to re

  9. Development of fuel cycle technology for molten-salt reactor systems

    International Nuclear Information System (INIS)

    Uhlir, J.

    2006-01-01

    Full text: Full text: The Molten-Salt Reactor (MSR) represents one of promising advanced reactor type assigned to the GEN IV reactor systems. It can be operated either as thorium breeder within the Th -133U fuel cycle or as actinide transmuter incinerating transuranium fuel. Essentially the main advantage of MSR comes out from the prerequisite, that this reactor type should be directly connected with the 'on-line' reprocessing of circulating liquid (molten-salt) fuel. This principle should allow very effective extraction of freshly constituted fissile material (233U). Besides, the on-line fuel salt clean up is necessary within a long run to keep the reactor in operation. As a matter of principle, it permits to clear away typical reactor poisons like xenon, krypton, lanthanides etc. and possibly also other products of burned plutonium and transmuted minor actinides. The fuel salt clean up technology should be linked with the fresh MSR fuel processing to continuously refill the new fuel (thorium or transuranics) into the reactor system. On the other hand, the technologies of fresh transuranium molten-salt fuel processing from the current LWR spent fuel and of the on-line reprocessing of MSR fuel represent two killing points of the whole MSR technology, which have to be successfully solved before MSR deployment in the future. There are three main pyrochemical partitioning techniques proposed for processing and/or reprocessing of MSR fuel: Fluoride volatilization processes, Molten salt / liquid metal extraction processes and Electrochemical separation processes. Two of them - Fluoride Volatility Method and Electrochemical separation process from fluoride media are under development in the Nuclear Research Institute Rez pic. R and D in the field of Fluoride Volatility Method is concentrated to the development and verification of experimental semi-pilot technology for LWR spent fuel reprocessing, which may result in a product the form and composition of which might be

  10. Graphite and carbonaceous materials in a molten salt nuclear reactor

    International Nuclear Information System (INIS)

    Rousseau, Ginette; Lecocq, Alfred; Hery, Michel.

    1982-09-01

    A project for a molten salt 1000 MWe reactor is studied by EDF-CEA teams. The design provides for a chromesco 3 vessel housing graphite structures in which the salt circulates. The salt (Th, U, Be and Li fluorides) is cooled by direct contact with lead. The graphites and carbonated materials, inert with respect to lead and the fuel salt, are being considered not only as moderators, but as reflectors and in the construction of the sections where the heat exchange takes place. On the basis of the problems raised in the operation of the reactor, a study programme on French experimental materials (Le Carbone Lorraine, SERS, SEP) has been defined. Hence, depending on the function or functions that the material is to ensure in the structure, the criteria of choice which follow will have to be examined: behaviour under irradiation, insertion of a fluid in the material, thermal properties required, mechanical properties required, utilization [fr

  11. Fuel salt and container material studies for MOSART transforming system

    Energy Technology Data Exchange (ETDEWEB)

    Ignatiev, V.; Feynberg, O.; Merzlyakov, A.; Surenkov, A.; Zagnitko, A. [National Research Center, Kurchatov Institute, Moscow (Russian Federation); Afonichkin, V.; Bovet, A.; Khokhlov, V. [Institute of High Temperature Electrochemisty, Ekaterinburg (Russian Federation); Subbotin, V.; Gordeev, M.; Panov, A.; Toropov, A. [Institute of Technical Physics, Snezhinsk (Russian Federation)

    2013-07-01

    A study is under progress to examine the feasibility of single stream Molten Salt Actinide Recycling and Transmuting system without and with Th support (MOSART) fuelled with different compositions of actinide tri-fluorides (AnF{sub 3}) from used LWR fuel. New fast-spectrum design options with homogeneous core and fuel salts with high enough solubility for AnF{sub 3} are being examined because of new goals. The flexibility of single fluid MOSART concept with Th support is underlined, particularly, possibility of its operation in self-sustainable mode (Conversion Ratio: CR=1) using different loadings and make up. The paper summarizes the most current status of fuel salt and container material data for the MOSART concept received within ISTC-3749 and ROSATOM-MARS projects. Key physical and chemical properties of various fluoride fuel salts are reported. The issues like salt purification, the electroreduction of U(IV) to U(III) in LiF-ThF{sub 4} and the electroreduction of Yb(III) to Yb(II) in LiF-NaF are detailed.

  12. Studies on the comparative effect of sodium fluoride on collagen ...

    African Journals Online (AJOL)

    Fluoride is an essential element for the normal development and growth of human beings. The main source of fluoride for humans is the intake of groundwater. At high levels, fluoride causes dental and skeletal fluorosis. In this study, control and sodium fluoride (NaF) treated groups of rats had significant (p < 0.05) higher ...

  13. Advanced CSiC composites for high-temperature nuclear heat transport with helium, molten salts, and sulphur-iodine thermochemical hydrogen process fluids

    International Nuclear Information System (INIS)

    Peterson, P.F.; Forsberg, Ch.W.; Pickard, P.S.

    2004-01-01

    This paper discusses the use of liquid-silicon-impregnated (LSI) carbon-carbon composites for the development of compact and inexpensive heat exchangers, piping, vessels and pumps capable of operating in the temperature range of 800 to 1 100 deg C with high-pressure helium, molten fluoride salts, and process fluids for sulfur-iodine thermochemical hydrogen production. LSI composites have several potentially attractive features, including ability to maintain nearly full mechanical strength to temperatures approaching 1 400 deg C, inexpensive and commercially available fabrication materials, and the capability for simple forming, machining and joining of carbon-carbon performs, which permits the fabrication of highly complex component geometries. In the near term, these materials may prove to be attractive for use with a molten-salt intermediate loop for the demonstration of hydrogen production with a gas-cooled high temperature reactor. In the longer term, these materials could be attractive for use with the molten-salt cooled advanced high temperature reactor, molten salt reactors, and fusion power plants. (author)

  14. Evaluation of toxic action of fluorides on agricultural plants

    Directory of Open Access Journals (Sweden)

    V. N. Grishko

    2007-03-01

    Full Text Available The toxicity of potassium fluoride, sodium fluoride and ammonium fluoride for pea, maize, oat and onion was studied. It was found that the level of the toxic influence had grown with increase of fluoride concentration in the media of growth (from 5 to 100 mg of F–/l. By increase of the toxic influence the agricultural crops are disposed in the following row: oat < onion < maize < pea. Ammonium fluoride demonstrates lesser toxicity, than potassium and sodium fluorides. Under low concentrations of fluoride compounds (5 and 10 mg of F–/l stimulation of roots growth is noted only for the oat.

  15. Optimization of hybrid polymer electrolytes with the effect of lithium salt concentration in PEO/PVdF-HFP blends

    Energy Technology Data Exchange (ETDEWEB)

    Pradeepa, P.; Edwin raj, S.; Sowmya, G.; Kalaiselvimary, J.; Ramesh Prabhu, M., E-mail: mkram83@gmail.com

    2016-03-15

    Highlights: • Polymer blends based on PVdF-HFP/PEO were prepared for Li-ion battery applications. • Structural and electrochemical studies were carried out on prepared electrolytes. • The electrolytes can be used as electrolyte in the possible device fabrications. - Abstract: Poly(ethylene oxide) (PEO) 6.25 wt%/poly(vinylidene fluoride-co-hexafluoropropylene) [P(VdF-HFP)] 18.75 wt% blend based electrolyte films containing different concentrations (2–10) wt% of lithium salt were prepared. The miscibility studies have been performed by using X-ray diffraction and Fourier transform infrared spectroscopy. The role of interaction between polymer hosts on conductivity is discussed using the results of a.c. impedance studies. A room temperature conductivity of 2.3912 × 10{sup −4} S cm{sup −1} has been obtained for PEO (6.25)–PVdF-HFP (18.75)–LiClO{sub 4} (8)–PC (67) polymer complex. The temperature dependence of the conductivity of polymer electrolyte seems to obey VTF relation. Electrochemical stability (3.3 V) was observed in the prepared polymer electrolyte. Reduction process and oxidation process of the prepared electrolyte system have also been evaluated by means of cyclic voltammetry. Thermogravimetric analysis results indicate thermal stability of PEO/PVdF-HFP lithium salt complexes. Roughness parameter of the sample having maximum ionic conductivity was studied by AFM. The morphology of the polymer complex is investigated by using SEM.

  16. Physiologic Conditions Affect Toxicity of Ingested Industrial Fluoride

    Directory of Open Access Journals (Sweden)

    Richard Sauerheber

    2013-01-01

    Full Text Available The effects of calcium ion and broad pH ranges on free fluoride ion aqueous concentrations were measured directly and computed theoretically. Solubility calculations indicate that blood fluoride concentrations that occur in lethal poisonings would decrease calcium below prevailing levels. Acute lethal poisoning and also many of the chronic effects of fluoride involve alterations in the chemical activity of calcium by the fluoride ion. Natural calcium fluoride with low solubility and toxicity from ingestion is distinct from fully soluble toxic industrial fluorides. The toxicity of fluoride is determined by environmental conditions and the positive cations present. At a pH typical of gastric juice, fluoride is largely protonated as hydrofluoric acid HF. Industrial fluoride ingested from treated water enters saliva at levels too low to affect dental caries. Blood levels during lifelong consumption can harm heart, bone, brain, and even developing teeth enamel. The widespread policy known as water fluoridation is discussed in light of these findings.

  17. Physiologic conditions affect toxicity of ingested industrial fluoride.

    Science.gov (United States)

    Sauerheber, Richard

    2013-01-01

    The effects of calcium ion and broad pH ranges on free fluoride ion aqueous concentrations were measured directly and computed theoretically. Solubility calculations indicate that blood fluoride concentrations that occur in lethal poisonings would decrease calcium below prevailing levels. Acute lethal poisoning and also many of the chronic effects of fluoride involve alterations in the chemical activity of calcium by the fluoride ion. Natural calcium fluoride with low solubility and toxicity from ingestion is distinct from fully soluble toxic industrial fluorides. The toxicity of fluoride is determined by environmental conditions and the positive cations present. At a pH typical of gastric juice, fluoride is largely protonated as hydrofluoric acid HF. Industrial fluoride ingested from treated water enters saliva at levels too low to affect dental caries. Blood levels during lifelong consumption can harm heart, bone, brain, and even developing teeth enamel. The widespread policy known as water fluoridation is discussed in light of these findings.

  18. Current status of fluoride volatility method development

    Energy Technology Data Exchange (ETDEWEB)

    Uhlir, J.; Marecek, M.; Skarohlid, J. [UJV - Nuclear Research Institute, Research Centre Rez, CZ-250 68 Husinec - Rez 130 (Czech Republic)

    2013-07-01

    The Fluoride Volatility Method is based on a separation process, which comes out from the specific property of uranium, neptunium and plutonium to form volatile hexafluorides whereas most of fission products (mainly lanthanides) and higher transplutonium elements (americium, curium) present in irradiated fuel form nonvolatile tri-fluorides. Fluoride Volatility Method itself is based on direct fluorination of the spent fuel, but before the fluorination step, the removal of cladding material and subsequent transformation of the fuel into a powdered form with a suitable grain size have to be done. The fluorination is made with fluorine gas in a flame fluorination reactor, where the volatile fluorides (mostly UF{sub 6}) are separated from the non-volatile ones (trivalent minor actinides and majority of fission products). The subsequent operations necessary for partitioning of volatile fluorides are the condensation and evaporation of volatile fluorides, the thermal decomposition of PuF{sub 6} and the finally distillation and sorption used for the purification of uranium product. The Fluoride Volatility Method is considered to be a promising advanced pyrochemical reprocessing technology, which can mainly be used for the reprocessing of oxide spent fuels coming from future GEN IV fast reactors.

  19. Electrodeposition of some metals and niobium superconducting alloys from molten fluorides

    International Nuclear Information System (INIS)

    Cohen, U.

    1978-01-01

    The major goal of this thesis was to study the feasibility of electrodeposition from molten fluorides of the pure elements niobium, aluminium, tin, germanium and silicon, and the niboium superconducting intermetallic compounds with these elements, and to prepare and study films of these materials in the form of coherent and uniform coatings. Decomposition potential measurements with a gold anode were carried out on the alkali fluoride solvent and the fluoride salt solutions of niobium, aluminum, tin, and germanium to provide important initial thermodynamic data. Attempts to codeposit niobium and aluminum invariably failed, niobium being the exclusive deposit in all cases. Codeposition of niobium--tin alloys was demonstrated. Of the four intermetallic compounds of the niobium--germanium system, three were obtained as single-phase coatings. The superconducting compound (A15 phase) was not successfully electrodeposited in a single-phase form. It was obtained, however, in phase-mixture coatings. Application of alternating square wave pulses produced substantial changes in the morphology of niobium deposits. Silicon electrocrystallization epitaxy (ECE) was demonstrated for the first time. Uniform, coherent, and well adherent coatings of polycrystalline Si with a grain diameter of up to 40 to 50 μm were plated onto nonalloying metal substrates, such as silver and tungsten.These processes offer some attractive features for both integrated circuit technology and silicon solar cell fabrication. Aluminum, tin, and germanium were also electrodeposited from molten fluorides

  20. Process and apparatus for extraction of gases produced during operation of a fused-salt nuclear reactor

    International Nuclear Information System (INIS)

    Blum, J.; Marie, J.

    1976-01-01

    The present invention relates to the field of fused-salt nuclear reactors and its object is the extraction of the gases produced in the course of operation of these reactors. The process according to the invention consists in placing into position a piece of material permeable for gases and impermeable for the used fused salts, for instance, a piece of graphite, in such a way that part of the surface of this piece is in contact with the circuit of the radioactive salts and another part connected to a gas suction device. The piece could also be scavenged in its mass by a flow of inert gas. Application is contemplated in reactors using a mixture of lithium fluoride, beryllium fluoride, and uranium and/or thorium fluoride. 10 claims, 2 drawing figures

  1. Fluoride gels for preventing dental caries in children and adolescents.

    Science.gov (United States)

    Marinho, Valeria C C; Worthington, Helen V; Walsh, Tanya; Chong, Lee Yee

    2015-06-15

    Topically applied fluoride gels have been widely used as a caries-preventive intervention in dental surgeries and school-based programmes for over three decades. This updates the Cochrane review of fluoride gels for preventing dental caries in children and adolescents that was first published in 2002. The primary objective is to determine the effectiveness and safety of fluoride gels in preventing dental caries in the child and adolescent population.The secondary objectives are to examine whether the effect of fluoride gels is influenced by the following: initial level of caries severity; background exposure to fluoride in water (or salt), toothpastes, or reported fluoride sources other than the study option(s); mode of use (self applied under supervision or operator-applied), and whether there is a differential effect between the tray and toothbrush methods of application; frequency of use (times per year) or fluoride concentration (ppm F). We searched the Cochrane Oral Health Group Trials Register (to 5 November 2014), the Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library 2014, Issue 11), MEDLINE via OVID (1946 to 5 November 2014), EMBASE via OVID (1980 to 5 November 2014), CINAHL via EBSCO (1980 to 5 November 2014), LILACS and BBO via the BIREME Virtual Health Library (1980 to 5 November 2014), ProQuest Dissertations and Theses (1861 to 5 November 2014) and Web of Science Conference Proceedings (1945 to 5 November 2014). We undertook a search for ongoing trials on ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform on 5 November 2014. We placed no restrictions on language or date of publication in the search of the electronic databases. We also searched reference lists of articles and contacted selected authors and manufacturers. Randomised or quasi-randomised controlled trials where blind outcome assessment was stated or indicated, comparing topically applied fluoride gel with placebo or no treatment in

  2. Thermodynamics of the conversion of calcium and magnesium fluorides to the parent metal oxides and hydrogen fluoride

    International Nuclear Information System (INIS)

    West, M.H.; Axler, K.M.

    1997-02-01

    The authors have used thermodynamic modeling to examine the reaction of calcium fluoride (CaF 2 ) and magnesium fluoride (MgF 2 ) with water (H 2 O) at elevated temperatures. The calculated, equilibrium composition corresponds to the global free-energy minimum for the system. Optimum, predicted reaction temperatures and reactant mole ratios are reported for the recovery of hydrogen fluoride (HF), a valuable industrial feedstock. Complete conversion of MgF 2 is found at 1,000 C and a ratio of 40 moles of H 2 O per 1 mole of MgF 2 . For CaF 2 , temperatures as high as 1,400 C are required for complete conversion at a corresponding mole ratio of 40 moles of H 2 O per 1 mole of CaF 2 . The authors discuss the presence of minor chemical constituents as well as the stability of various potential container materials for the pyrohydrolysis reactions at elevated temperatures. CaF 2 and MgF 2 slags are available as wastes at former uranium production facilities within the Department of Energy Complex and other facilities regulated by the Nuclear Regulatory Commission. Recovery of HF from these wastes is an example of environmental remediation at such facilities

  3. Comparative proteomic analysis of fluoride treated rat bone provides new insights into the molecular mechanisms of fluoride toxicity.

    Science.gov (United States)

    Wei, Yan; Zeng, Beibei; Zhang, Hua; Chen, Cheng; Wu, Yanli; Wang, Nanlan; Wu, Yanqiu; Zhao, Danqing; Zhao, Yuxi; Iqbal, Javed; Shen, Liming

    2018-07-01

    Long-term excessive intake of fluoride (F) could lead to chronic fluorosis. To explore the underlying molecular mechanisms, present study is designed to elucidate the effect of fluoride on proteome expression of bone in sodium fluoride (NaF)-treated SD rats. Hematoxylin and eosin (H&E) staining was used to determine the severity of osteofluorosis, and bone samples were submitted for iTRAQ analysis. The results showed that the cortical thickness and trabecular area of femur bone in medium- and high-dose groups were higher than in control group. Contrary to this, trabecular area was reduced in the low-dose group, indicating that the bone mass was increased in medium- and high-dose groups, and decreased in the low-dose group. Thirteen (13), 35, and 34 differentially expressed proteins were identified in low-, medium-, and high-dose group, respectively. The medium- and high-dose groups shared a more similar protein expression pattern. These proteins were mainly associated with collagen metabolism, proteoglycans (PGs), matrix metalloproteinases (MMPs), etc. The results suggested that the effect of NaF on SD rats is in a dose-dependent manner. Some key proteins found here may be involved in affecting the bone tissues and bone marrow or muscle, and account for the complex pathology and clinical symptoms of fluorosis. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Effect of oral calcium and calcium + fluoride treatments on mouse bone properties during suspension

    Science.gov (United States)

    Simske, S. J.; Luttges, M. W.; Allen, K. A.; Spooner, B. S. (Principal Investigator)

    1992-01-01

    The bone effects of oral dosages of calcium chloride with or without supplementary sodium fluoride were assessed in antiorthostatically suspended mice. Two calcium dosages were used to replace half (3.1 mM) or all(6.3 mM) of the dietary calcium lost due to reduced food intake by the suspended mice. Two groups of 6.3 mM CaCl2-treated mice were additionally treated with 0.25 or 2.5 mM NaF. The results indicate that supplementation of the mouse drinking water with calcium salts prevents bone changes induced by short-term suspension, while calcium salts in combination with fluoride are less effective as fluoride dosage increases. However, the calcium supplements change the relationship between the femur mechanical properties and the mineral composition of the bone. Because of this, it appears that oral calcium supplements are effective through a mechanism other than simple dietary supplementation and may indicate a dependence of bone consistency on systemic and local fluid conditions.

  5. Application of Titanium Compounds to Reduce Fluoride Ion in Water Resources with High Fluoride Ion Contents

    Directory of Open Access Journals (Sweden)

    Fariborz Riahi

    2005-06-01

    Full Text Available The present work describes studies on the sorption of fluoride ions from water by titanium compounds used in water treatment to reduce fluoride content in water resources. There are different methods of reducing fluoride ion in water, each associated with specific problems such as secondary contamination, environmental contamination, high costs, or the need for primary and secondary treatment. In this study, application of titanium sulfate and Metatitanic acid produced from titanium ore concentrate (ileminite is investigated in the removal of fluoride ion and the possibility of complete purification of fluorine containing wastewater is examined to determine the optimal conditions. Metatitanic acid has a great sorption property for fluoride ion. Also titanium sulfate is a suitable and more effective material for this purpose. Efficiency of this material in reducing fluoride ion content is 99.9% and it is possible to refresh sorbet material for reuse without problems arising from Ti+4 ion contamination.

  6. New Insight on the Response of Bacteria to Fluoride

    OpenAIRE

    Breaker, R.R.

    2012-01-01

    Fluoride has been used for decades to prevent caries and it is well established that this anion can inhibit the growth of bacteria. However, the precise effects that fluoride has on bacteria and the mechanisms that bacteria use to overcome fluoride toxicity have largely remained unexplored. Recently, my laboratory reported the discovery of biological systems that bacteria use to sense fluoride and reduce fluoride toxicity. These sensors and their associated genes are very widespread in biolog...

  7. Physiologic Conditions Affect Toxicity of Ingested Industrial Fluoride

    OpenAIRE

    Richard Sauerheber

    2013-01-01

    The effects of calcium ion and broad pH ranges on free fluoride ion aqueous concentrations were measured directly and computed theoretically. Solubility calculations indicate that blood fluoride concentrations that occur in lethal poisonings would decrease calcium below prevailing levels. Acute lethal poisoning and also many of the chronic effects of fluoride involve alterations in the chemical activity of calcium by the fluoride ion. Natural calcium fluoride with low solubility and toxicity ...

  8. Potential fluoride toxicity from oral medicaments: A review

    OpenAIRE

    Rizwan Ullah; Muhammad Sohail Zafar; Nazish Shahani

    2017-01-01

    The beneficial effects of fluoride on human oral health are well studied. There are numerous studies demonstrating that a small amount of fluoride delivered to the oral cavity decreases the prevalence of dental decay and results in stronger teeth and bones. However, ingestion of fluoride more than the recommended limit leads to toxicity and adverse effects. In order to update our understanding of fluoride and its potential toxicity, we have described the mechanisms of fluoride metabolism, tox...

  9. Eukaryotic resistance to fluoride toxicity mediated by a widespread family of fluoride export proteins

    OpenAIRE

    Li, Sanshu; Smith, Kathryn D.; Davis, Jared H.; Gordon, Patricia B.; Breaker, Ronald R.; Strobel, Scott A.

    2013-01-01

    Although fluoride is plentiful in the environment and is commonly used at high concentrations in oral hygiene products, little has been known about how biological systems overcome the toxic effects of this anion. We demonstrate that a protein called FEX in many fungi is essential for cell survival in the presence of high fluoride concentrations. The protein is required for the rapid expulsion of cytoplasmic fluoride, indicating that many eukaryotic species that carry FEX genes likely avoid fl...

  10. No calcium-fluoride-like deposits detected in plaque shortly after a sodium fluoride mouthrinse.

    Science.gov (United States)

    Vogel, G L; Tenuta, L M A; Schumacher, G E; Chow, L C

    2010-01-01

    Plaque 'calcium-fluoride-like' (CaF(2)-like) and fluoride deposits held by biological/bacterial calcium fluoride (Ca-F) bonds appear to be the source of cariostatic concentrations of fluoride in plaque fluid. The aim of this study was to quantify the amounts of plaque fluoride held in these reservoirs after a sodium fluoride rinse. 30 and 60 min after a 228 microg/g fluoride rinse, plaque samples were collected from 11 volunteers. Each sample was homogenized, split into 2 aliquots (aliquots 1 and 2), centrifuged, and the recovered plaque fluid combined and analyzed using microelectrodes. The plaque mass from aliquot 1 was retained. The plaque mass from aliquot 2 was extracted several times with a solution having the same fluoride, calcium and pH as the plaque fluid in order to extract the plaque CaF(2)-like deposits. The total fluoride in both aliquots was then determined. In a second experiment, the extraction completeness was examined by applying the above procedure to in vitro precipitates containing known amounts of CaF(2)-like deposits. Nearly identical fluoride concentrations were found in both plaque aliquots. The extraction of the CaF(2)-like precipitates formed in vitro removed more than 80% of these deposits. The results suggest that either CaF(2)-like deposits were not formed in plaque or, if these deposits had been formed, they were rapidly lost. The inability to form persistent amounts of CaF(2)-like deposits in plaque may account for the relatively rapid loss of plaque fluid fluoride after the use of conventional fluoride dentifrices or rinses. (c) 2010 S. Karger AG, Basel.

  11. Fluoride releasing and enamel demineralization around orthodontic brackets by fluoride-releasing composite containing nanoparticles.

    Science.gov (United States)

    Melo, Mary A S; Morais, Weslanny A; Passos, Vanara F; Lima, Juliana P M; Rodrigues, Lidiany K A

    2014-05-01

    Fluoride-containing materials have been suggested to control enamel demineralization around orthodontic brackets during the treatment with fixed appliances. The improvement of their properties has been made through innovations, such as the application of nanotechnology by incorporation of nanofillers. This in vitro study evaluated the capacity of fluoride releasing and enamel demineralization inhibition of fluoride-releasing nanofilled cement around orthodontic brackets using an artificial caries biofilm model. Forty bovine enamel discs were selected by evaluating surface microhardness and randomized into four groups (n = 10): non-fluoride-releasing microfilled composite, fluoride-releasing microfilled composite, resin-modified glass ionomer cement (RMGI), and fluoride-releasing nanofilled composite (FN). After brackets bonding in each disc, the specimens were subjected to a cariogenic challenge through a Streptococcus mutans biofilm model. After the experimental period, the biofilm formed around the brackets was collected for fluoride analysis and the mineral loss around the brackets was determined by integrated demineralization via cross-sectional microhardness measurement at 20 and 70 μm from the bracket margin. Additionally, samples of each group were subjected to energy-dispersive X-ray spectroscopy (EDX) analysis examined under a scanning electron microscopy (SEM). ANOVA followed by Tukey test were applied for fluoride concentration and mineral loss data, respectively. At both distances, only RMGI statistically differed from the other groups presenting the lowest demineralization, although there was a trend to a lower demineralization of enamel around brackets in FN group. Similar condition was found to fluoride concentration and EDX/SEM analysis. Under the cariogenic exposure condition of this study, the fluoride-releasing nanofilled material had similar performance to fluoride-releasing microfilled materials. The presence of nanofillers in the fluoride

  12. Fluoride exposure and indicators of thyroid functioning in the Canadian population: implications for community water fluoridation.

    Science.gov (United States)

    Barberio, Amanda M; Hosein, F Shaun; Quiñonez, Carlos; McLaren, Lindsay

    2017-10-01

    There are concerns that altered thyroid functioning could be the result of ingesting too much fluoride. Community water fluoridation (CWF) is an important source of fluoride exposure. Our objectives were to examine the association between fluoride exposure and (1) diagnosis of a thyroid condition and (2) indicators of thyroid functioning among a national population-based sample of Canadians. We analysed data from Cycles 2 and 3 of the Canadian Health Measures Survey (CHMS). Logistic regression was used to assess associations between fluoride from urine and tap water samples and the diagnosis of a thyroid condition. Multinomial logistic regression was used to examine the relationship between fluoride exposure and thyroid-stimulating hormone (TSH) level (low/normal/high). Other available variables permitted additional exploratory analyses among the subset of participants for whom we could discern some fluoride exposure from drinking water and/or dental products. There was no evidence of a relationship between fluoride exposure (from urine and tap water) and the diagnosis of a thyroid condition. There was no statistically significant association between fluoride exposure and abnormal (low or high) TSH levels relative to normal TSH levels. Rerunning the models with the sample constrained to the subset of participants for whom we could discern some source(s) of fluoride exposure from drinking water and/or dental products revealed no significant associations. These analyses suggest that, at the population level, fluoride exposure is not associated with impaired thyroid functioning in a time and place where multiple sources of fluoride exposure, including CWF, exist. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  13. Adverse Effects of High Concentrations of Fluoride on Characteristics of the Ovary and Mature Oocyte of Mouse

    Science.gov (United States)

    Yin, Songna; Song, Chao; Wu, Haibo; Chen, Xin; Zhang, Yong

    2015-01-01

    Reproductive toxicity has been an exciting topic of research in reproductive biology in recent years. Soluble fluoride salts are toxic at high concentrations; their reproductive toxicity was assessed in this study by administering different fluoride salt concentrations to mice. Continuous feeding for five weeks resulted in damage to the histological architecture of ovaries. The expression of genes, including Dazl, Stra8, Nobox, Sohlh1, and ZP3 gene, associated with oocyte formation were much lower in the experimental group as compared with the control group. The number of in vitro fertilization of mature oocytes were also much lower in the experimental group as compared with control. Moreover, the fertility of female mice, as assessed by mating with normal male mice, was also lower in experimental compared with control groups. The expression of the oocyte-specific genes: Bmp15, Gdf9, H1oo, and ZP2, which are involved in oocyte growth and the induction of the acrosome reaction, decreased with the fluoride administration. DNA methylation and histone acetylation (H3K18ac and H3K9ac) are indispensable for germline development and genomic imprinting in mammals, and fluoride administration resulted in reduced levels of H3K9ac and H3K18ac in the experimental group as compared with the control group, as detected by immunostaining. Our results indicate that the administration of high concentrations of fluoride to female mice significantly reduced the number of mature oocytes and hampered their development and fertilization. Thus, this study lays a foundation for future studies on fluoride-induced reproductive disorders in women. PMID:26053026

  14. Adverse Effects of High Concentrations of Fluoride on Characteristics of the Ovary and Mature Oocyte of Mouse.

    Directory of Open Access Journals (Sweden)

    Songna Yin

    Full Text Available Reproductive toxicity has been an exciting topic of research in reproductive biology in recent years. Soluble fluoride salts are toxic at high concentrations; their reproductive toxicity was assessed in this study by administering different fluoride salt concentrations to mice. Continuous feeding for five weeks resulted in damage to the histological architecture of ovaries. The expression of genes, including Dazl, Stra8, Nobox, Sohlh1, and ZP3 gene, associated with oocyte formation were much lower in the experimental group as compared with the control group. The number of in vitro fertilization of mature oocytes were also much lower in the experimental group as compared with control. Moreover, the fertility of female mice, as assessed by mating with normal male mice, was also lower in experimental compared with control groups. The expression of the oocyte-specific genes: Bmp15, Gdf9, H1oo, and ZP2, which are involved in oocyte growth and the induction of the acrosome reaction, decreased with the fluoride administration. DNA methylation and histone acetylation (H3K18ac and H3K9ac are indispensable for germline development and genomic imprinting in mammals, and fluoride administration resulted in reduced levels of H3K9ac and H3K18ac in the experimental group as compared with the control group, as detected by immunostaining. Our results indicate that the administration of high concentrations of fluoride to female mice significantly reduced the number of mature oocytes and hampered their development and fertilization. Thus, this study lays a foundation for future studies on fluoride-induced reproductive disorders in women.

  15. Detection of trace fluoride in serum and urine by online membrane-based distillation coupled with ion chromatography.

    Science.gov (United States)

    Lou, Chaoyan; Guo, Dandan; Wang, Nani; Wu, Shuchao; Zhang, Peimin; Zhu, Yan

    2017-06-02

    An online membrane-based distillation (MBD) coupled with ion chromatography (IC) method was proposed for automatic detection of trace fluoride (F - ) in serum and urine samples. The system consisted of a sample vessel, a lab-made membrane module and an ion chromatograph. Hydrophobic polytetrafluoroethylene (PTFE) hollow fiber membrane was used in MBD which was directly performed in serum and urine samples to eliminate the matrix interferences and enrich fluoride, while enabling automation. The determination of fluoride in biological samples was carried out by IC with suppressed conductometric detection. The proposed method feasibly determined trace fluoride in serum and urine matrices with the optimized parameters, such as acid concentration, distillation temperature, and distillation time, etc. Fluoride exhibited satisfactory linearity in the range of 0.01-5.0mg/L with a correlation coefficient of 0.9992. The limit of detection (LOD, S/N=3) and limit of quantification (LOQ, S/N=10) were 0.78μg/L and 2.61μg/L, respectively. The relative standard deviations of peak area and peak height were all less than 5.15%. The developed method was validated for the determination of fluoride in serum and urine with good spiked recoveries ranging between 97.1-101.9%. This method also can be proposed as a suitable alternative for the analysis of fluoride in other complex biological samples. Copyright © 2017. Published by Elsevier B.V.

  16. Seismic anisotropy in deforming salt bodies

    Science.gov (United States)

    Prasse, P.; Wookey, J. M.; Kendall, J. M.; Dutko, M.

    2017-12-01

    Salt is often involved in forming hydrocarbon traps. Studying salt dynamics and the deformation processes is important for the exploration industry. We have performed numerical texture simulations of single halite crystals deformed by simple shear and axial extension using the visco-plastic self consistent approach (VPSC). A methodology from subduction studies to estimate strain in a geodynamic simulation is applied to a complex high-resolution salt diapir model. The salt diapir deformation is modelled with the ELFEN software by our industrial partner Rockfield, which is based on a finite-element code. High strain areas at the bottom of the head-like strctures of the salt diapir show high amount of seismic anisotropy due to LPO development of halite crystals. The results demonstrate that a significant degree of seismic anisotropy can be generated, validating the view that this should be accounted for in the treatment of seismic data in, for example, salt diapir settings.

  17. Synthesis, crystal structures, and characterization of double complex salts [Au(en)2][Rh(NO2)6]·2H2O and [Au(en)2][Rh(NO2)6

    Science.gov (United States)

    Plyusnin, Pavel E.; Makotchenko, Evgenia V.; Shubin, Yury V.; Baidina, Iraida A.; Korolkov, Ilya V.; Sheludyakova, Liliya A.; Korenev, Sergey V.

    2015-11-01

    Double complex salts of rhodium(III) and gold(III) of the composition [Au(en)2][Rh(NO2)6]·2H2O (1) and [Au(en)2][Rh(NO2)6] (2) have been prepared. Crystal structures of the compounds have been determined by single crystal X-ray diffraction. The compounds have been characterized by PXRD, IR, far-IR, CHN and DTA. The complexes have a layered structures. The presence of water in 1 makes the structure of the hydrated DCS less dense as compared to the anhydrous one. The environment of the cation and the anion in the two structures is the same, oxygen atoms of the nitro groups are involved in hydrogen bonds N-H⋯O, N⋯O distances being approximately the same. The structures of 1 and 2 are notable in having shortened contacts between the gold atoms and the oxygen atoms of the nitro groups of the neighboring complex anions. The thermal behavior of the complexes in a hydrogen atmosphere was investigated. The final product of thermolysis prepared at the temperature 600°C is a two-phase mixture of pure metallic gold and the solid solution Rh0.93Au0.07.

  18. Salt bridges: geometrically specific, designable interactions.

    Science.gov (United States)

    Donald, Jason E; Kulp, Daniel W; DeGrado, William F

    2011-03-01

    Salt bridges occur frequently in proteins, providing conformational specificity and contributing to molecular recognition and catalysis. We present a comprehensive analysis of these interactions in protein structures by surveying a large database of protein structures. Salt bridges between Asp or Glu and His, Arg, or Lys display extremely well-defined geometric preferences. Several previously observed preferences are confirmed, and others that were previously unrecognized are discovered. Salt bridges are explored for their preferences for different separations in sequence and in space, geometric preferences within proteins and at protein-protein interfaces, co-operativity in networked salt bridges, inclusion within metal-binding sites, preference for acidic electrons, apparent conformational side chain entropy reduction on formation, and degree of burial. Salt bridges occur far more frequently between residues at close than distant sequence separations, but, at close distances, there remain strong preferences for salt bridges at specific separations. Specific types of complex salt bridges, involving three or more members, are also discovered. As we observe a strong relationship between the propensity to form a salt bridge and the placement of salt-bridging residues in protein sequences, we discuss the role that salt bridges might play in kinetically influencing protein folding and thermodynamically stabilizing the native conformation. We also develop a quantitative method to select appropriate crystal structure resolution and B-factor cutoffs. Detailed knowledge of these geometric and sequence dependences should aid de novo design and prediction algorithms. Copyright © 2010 Wiley-Liss, Inc.

  19. Quantitative infrared analysis of hydrogen fluoride

    International Nuclear Information System (INIS)

    Manuta, D.M.

    1997-04-01

    This work was performed at the Portsmouth Gaseous Diffusion Plant where hydrogen fluoride is produced upon the hydrolysis of UF 6 . This poses a problem for in this setting and a method for determining the mole percent concentration was desired. HF has been considered to be a non-ideal gas for many years. D. F. Smith utilized complex equations in his HF studies in the 1950s. We have evaluated HF behavior as a function of pressure from three different perspectives. (1) Absorbance at 3877 cm -1 as a function of pressure for 100% HF. (2) Absorbance at 3877 cm -1 as a function of increasing partial pressure HF. Total pressure = 300 mm HgA maintained with nitrogen. (3) Absorbance at 3877 cm -1 for constant partial pressure HF. Total pressure is increased to greater than 800 mm HgA with nitrogen. These experiments have shown that at partial pressures up to 35mm HgA, HIF follows the ideal gas law. The absorbance at 3877 cm -1 can be quantitatively analyzed via infrared methods

  20. Removal of fluoride from aqueous nitric acid

    International Nuclear Information System (INIS)

    Pruett, D.J.; Howerton, W.B.; Mailen, J.C.

    1981-06-01

    Several methods for removing fluoride from aqueous nitric acid were investigated and compared with the frequently used aluminum nitrate-calcium nitrate (Ca 2+ -Al 3+ ) chemical trap-distillation system. Zirconium oxynitrate solutions were found to be superior in preventing volatilization of fluoride during distillation of the nitric acid, producing decontamination factors (DFs) on the order of 2 x 10 3 (vs approx. 500 for the Ca 2+ -Al 3+ system). Several other metal nitrate systems were tested, but they were less effective. Alumina and zirconia columns proved highly effective in removing HF from HF-HNO 3 vapors distilled through the columns; fluoride DFs on the order of 10 6 and 10 4 , respectively, were obtained. A silica gel column was very effective in adsorbing HF from HF-HNO 3 solutions, producing a fluoride DF of approx. 10 4

  1. TECHNICAL AND ECONOMIC EVALUATION OF THE SEPARATION OF LIGHT OLEFINS (ETHYLENE AND PROPYLENE) BY USING p-COMPLEXATION WITH SILVER SALTS

    OpenAIRE

    Salgado-Gordon, Hernando-José; Valbuena-Moreno, Gleidy

    2011-01-01

    ABSTRACT Conventional processes for separation of ethylene and propylene until reaching petrochemical grade are energy intensive. Therefore, alternative separation methods, such as chemical affinity based technologies, are an interesting alternative for designing more sustainable processes. p-Complexation of the silver ion (Ag+) is one of these technologies. In this study, p-complexation is compared to the conventional technologies from process and economic points of view, in order to determi...

  2. Complexation of 1,3-dimorpholinopropane with Hg(II) and Zn(II) salts: Synthese, crystal structures and antibacterial studies

    Czech Academy of Sciences Publication Activity Database

    Goudarziafshar, H.; Yousefi, S.; Abbasityula, Y.; Dušek, Michal; Eigner, Václav; Rezaeivala, M.; Özbek, N.

    2015-01-01

    Roč. 31, č. 6 (2015), s. 1076-1084 ISSN 1001-4861 R&D Projects: GA ČR(CZ) GA14-03276S Institutional support: RVO:68378271 Keywords : crystal structure * 1,3-dimorpholinopropane * antibacterial activity * Hg(II) complex * Zn(II) complex Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 0.488, year: 2015

  3. Fast Spectrum Molten Salt Reactor Options

    Energy Technology Data Exchange (ETDEWEB)

    Gehin, Jess C [ORNL; Holcomb, David Eugene [ORNL; Flanagan, George F [ORNL; Patton, Bruce W [ORNL; Howard, Rob L [ORNL; Harrison, Thomas J [ORNL

    2011-07-01

    During 2010, fast-spectrum molten-salt reactors (FS-MSRs) were selected as a transformational reactor concept for light-water reactor (LWR)-derived heavy actinide disposition by the Department of Energy-Nuclear Energy Advanced Reactor Concepts (ARC) program and were the subject of a preliminary scoping investigation. Much of the reactor description information presented in this report derives from the preliminary studies performed for the ARC project. This report, however, has a somewhat broader scope-providing a conceptual overview of the characteristics and design options for FS-MSRs. It does not present in-depth evaluation of any FS-MSR particular characteristic, but instead provides an overview of all of the major reactor system technologies and characteristics, including the technology developments since the end of major molten salt reactor (MSR) development efforts in the 1970s. This report first presents a historical overview of the FS-MSR technology and describes the innovative characteristics of an FS-MSR. Next, it provides an overview of possible reactor configurations. The following design features/options and performance considerations are described including: (1) reactor salt options-both chloride and fluoride salts; (2) the impact of changing the carrier salt and actinide concentration on conversion ratio; (3) the conversion ratio; (4) an overview of the fuel salt chemical processing; (5) potential power cycles and hydrogen production options; and (6) overview of the performance characteristics of FS-MSRs, including general comparative metrics with LWRs. The conceptual-level evaluation includes resource sustainability, proliferation resistance, economics, and safety. The report concludes with a description of the work necessary to begin more detailed evaluation of FS-MSRs as a realistic reactor and fuel cycle option.

  4. Fluoride method for silicon determination i silicovadium

    International Nuclear Information System (INIS)

    Komarnitskaya, N.N.; Sergeev, K.I.; Shamraj, Z.Ya.

    1977-01-01

    The method used was based on formation of a silicon-potassium fluoride-sodium sediment in strongly acid medium in the presence of excess potassium chloride which decreased the sediment solubility. The sediment was dissolved in hot water to titrate the resultant hydrofluoric acid with a caustic potash solution in the presence of phenolphthalein. Gravity hydrochloric and volumetric fluoride methods were used to compare the results of silicon estimation

  5. Recovery of fluoride ion selective electrode

    International Nuclear Information System (INIS)

    Monteiro, R.P.G.

    1988-01-01

    A recovery procedure of fluoride ion selective electrode based upon the body radiography of inactive electrode and introduction of suitable internal regeneration solution, is developed. The recovered electrode was tested in standard solutions of fluoride ions (10 sup5) to 10 -1M showing as good performance as the new one. The fluor determination by potentiometric measurements with selective electrode is used in nuclear fuel cycle for quality control of thorium and uranium mixed oxide pellets and pellets of uranium dioxides. (author) [pt

  6. Dye-Sensitized Molecular Charge Transfer Complexes: Magnetic and Conduction Properties in the Photoexcited States of Ni(dmit2 Salts Containing Photosensitive Dyes

    Directory of Open Access Journals (Sweden)

    Ryoma Yamamoto

    2017-05-01

    Full Text Available Photosensitive dyes often induce charge transfer (CT between adjacent chemical species and themselves under irradiation of appropriate wavelengths. Because of the reversibility and selectivity of such CT, it is considered to be interesting to utilize such dyes as optically controllable trigger components for conduction and magnetism in the photoexcited states of organic materials. Based on this idea, such a type of new salts, i.e., γ- and δ-DiCC[Ni(dmit2] in addition to DiCC2[Ni(dmit2]3 have been prepared, characterized and their physical and structural properties have been examined both under dark and irradiated conditions (dmit2− = 1,3-dithiole-2-thione-4,5-dithiolate, DiCC+ = 3,3′-Dihexyloxacarbocyanine monocation. Among them, under UV (254–450 nm irradiation, δ-DiCC[Ni(dmit2] exhibited photoconductivity being six times as high as its dark conductivity at room temperature. The electron spin resonance (ESR spectra have demonstrated that there are photoexcited spins on both DiCC and [Ni(dmit2] species as a result of the CT transition between them, serving as localized spins (DiCC and carriers ([Ni(dmit2], respectively. The results obtained in this work have indicated that the strategy mentioned above is effective in developing organic photoresponsive semiconductors with paramagnetism.

  7. Fluoride loaded polymeric nanoparticles for dental delivery.

    Science.gov (United States)

    Nguyen, Sanko; Escudero, Carlos; Sediqi, Nadia; Smistad, Gro; Hiorth, Marianne

    2017-06-15

    The overall aim of the present paper was to develop fluoride loaded nanoparticles based on the biopolymers chitosan, pectin, and alginate, for use in dental delivery. First, the preparation of nanoparticles in the presence of sodium fluoride (NaF) as the active ingredient by ionic gelation was investigated followed by an evaluation of their drug entrapment and release properties. Chitosan formed stable, spherical, and monodisperse nanoparticles in the presence of NaF and tripolyphoshate as the crosslinker, whereas alginate and pectin were not able to form any definite nanostructures in similar conditions. The fluoride loading capacity was found to be 33-113ppm, and the entrapment efficiency 3.6-6.2% for chitosan nanoparticles prepared in 0.2-0.4% (w/w) NaF, respectively. A steady increase in the fluoride release was observed for chitosan nanoparticles prepared in 0.2% NaF both in pH5 and 7 until it reached a maximum at time point 4h and maintained at this level for at least 24h. Similar profiles were observed for formulations prepared in 0.4% NaF; however the fluoride was released at a higher level at pH5. The low concentration, but continuous delivery of fluoride from the chitosan nanoparticles, with possible expedited release in acidic environment, makes these formulations highly promising as dental delivery systems in the protection against caries development. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Well Waters Fluoride in Enugu, Nigeria

    Directory of Open Access Journals (Sweden)

    ISI Ogbu

    2012-03-01

    Full Text Available Abnormal fluoride levels in drinking water have been associated with adverse health effects. To determine the fluoride content of well waters in Enugu, southeastern Nigeria, water samples from 50 artisan wells chosen by multistage sampling procedure from the 5 zones of Enugu municipality were analyzed in duplicates for their fluoride content. The zonal mean values were 0.60, 0.70, 0.62, 0.62, and 0.63 mg/L for Abakpa Nike, Achara Layout, Obiagu/ Ogui, Trans Ekulu and Uwani, respectively (p<0.05. The mean value for the whole city was 0.63 mg/L. Although, the mean level of fluoride recorded in this study is currently within safe limits (1.5 mg/L, WHO 2011, it is important to monitor continuously the fluoride content of well waters in the municipality in view of the increasing industrial activities going on in the city and heavy reliance on well water for domestic purposes and the widespread use of consumer products containing fluoride.

  9. THE USE OF FLUORIDE AND ITS EFFECT ON HEALTH

    Directory of Open Access Journals (Sweden)

    Domen Kanduti

    2016-07-01

    Full Text Available Appropriate oral health care is fundamental for any individual’s health. Dental caries is still one of the major public health problems. The most effective way of caries prevention is the use of fluoride. Fluoride occurs naturally in our environment and is always present in our lives. However, the concentration differs from area to area. Exposure can occur through diet, respiration and fluoride supplements. During pregnancy, the placenta acts as a barrier. The fluoride, therefore, crosses the placenta in low concentrations. Drinking water in Slovenia is not fluoridated; the amount of naturally present fluoride is very low. Fluoride can be toxic in extremely high concentrations. The most important effect of fluoride on caries incidence is through its role in the process of remineralisation and demineralisation of tooth enamel. The European Academy of Paediatric Dentistry (EAPD recommends a preventive topical use of fluoride supplements because of their cariostatic effect. 

  10. Salt splitting with ceramic membranes

    International Nuclear Information System (INIS)

    Kurath, D.

    1996-01-01

    The purpose of this task is to develop ceramic membrane technologies for salt splitting of radioactively contaminated sodium salt solutions. This technology has the potential to reduce the low-level waste (LLW) disposal volume, the pH and sodium hydroxide content for subsequent processing steps, the sodium content of interstitial liquid in high-level waste (HLW) sludges, and provide sodium hydroxide free of aluminum for recycle within processing plants at the DOE complex. Potential deployment sites include Hanford, Savannah River, and Idaho National Engineering Laboratory (INEL). The technical approach consists of electrochemical separation of sodium ions from the salt solution using sodium (Na) Super Ion Conductors (NaSICON). As the name implies, sodium ions are transported rapidly through these ceramic crystals even at room temperatures

  11. Synthesis, spectroscopic and thermal characterization of sulpiride complexes of iron, manganese, copper, cobalt, nickel, and zinc salts. Antibacterial and antifungal activity

    Science.gov (United States)

    Mohamed, Gehad G.; Soliman, Madiha H.

    2010-08-01

    Sulpiride (SPR; L) is a substituted benzamide antipsychotic which is reported to be a selective antagonist of central dopamine receptors and claimed to have mood-elevating properties. The ligation behaviour of SPR drug is studied in order to give an idea about its potentiality towards some transition metals in vitro systems. Metal complexes of SPR have been synthesized by reaction with different metal chlorides. The metal complexes of SPR with the formula [MCl 2(L) 2(H 2O) 2]· nH 2O [M = Mn(II), Co(II), Ni(II), Cu(II) and Zn(II); n = 0-2] and [FeCl 2(HL)(H 2O) 3]Cl·H 2O have been synthesized and characterized using elemental analysis (CHN), electronic (infrared, solid reflectance and 1H NMR spectra) and thermal analyses (TG and DTA). The molar conductance data reveal that the bivalent metal chelates are non-electrolytes while Fe(III) complex is 1:1 electrolyte. IR spectra show that SPR is coordinated to the metal ions in a neutral monodentate manner with the amide O. From the magnetic and solid reflectance spectra, octahedral geometry is suggested. The thermal decomposition processes of these complexes were discussed. The correlation coefficient, the activation energies, E*, the pre-exponential factor, A, and the entropies, Δ S*, enthalpies, Δ H*, Gibbs free energies, Δ G*, of the thermal decomposition reactions have been derived from thermogravimetric (TG) and differential thermogravimetric (DTG) curves. The synthesized ligand and its metal complexes were also screened for their antibacterial and antifungal activity against bacterial species ( Escherichia coli and Staphylococcus aureus) and fungi ( Aspergillus flavus and Candida albicans). The activity data show that the metal complexes are found to have antibacterial and antifungal activity than the parent drug and less than the standard.

  12. Estimating concentration of fluoride in edible leaves locally grown around Raipur, Chhattisgarh

    Directory of Open Access Journals (Sweden)

    Anubhuti Jain

    2017-01-01

    Full Text Available Introduction: Fluorine is the 13th most abundant element in the earth crust and is available in various environmental, clinical, and food samples in varied concentrations. Aim: To estimate concentration of fluoride in five medicinal and five nonmedicinal edible leaves locally grown around Raipur, Chhattisgarh, India. Materials and Methods: Samples of ten medicinal and nonmedicinal edible leaves, namely, spinach (Spinacia oleracea, coriander leaves (Coriandrum sativum, chawli bhaji (Amaranthus spinach, lal bhaji (Alternanthera bettzickiana, mooli bhaji (Raphanus sativus, neem (Azadirachta indica, tulsi (Ocimum tenuiflorum, mint leaves (Mentha longifolia, betel leaves (Piper betle, and bael leaves (Aegle marmelos were collected in the clean polyethene bags. After thorough washing with water, leaves were left to dry in ambient temperature and crushed into powder using a mixer grinder. One gram of each of the powdered samples was taken and analyzed for fluoride concentration using a 2-(4-sulfophenylazo 1,8-dihydroxy-3,6-naphthalenedisulfonic acid trisodium salt spectrophotometric method. Results: The presence of fluoride in varied concentrations in locally grown edible leaves were analyzed. The highest concentration of fluoride was reported in tulsi (6.0 μg/g and lowest in mint leaves (1.1 μg/g. Two edible leaves, neem and bael, showed fluoride concentration below detection limit. Conclusion: Knowledge regarding the importance of edible leaves may be lost in the near future unless efforts are made to educate younger generations about their importance. Hence, the time has come to make good use of centuries-old knowledge through modern approaches for their better economic and therapeutic utilization.

  13. Chemisorption of uranium hexa-fluoride on sodium fluoride pellets

    Energy Technology Data Exchange (ETDEWEB)

    Kalburgi, A K; Sanyal, A; Puranik, V D; Bhattacharjee, B [Chemical Technology Division, Bhabha Atomic Research Centre, Mumbai (India)

    1994-06-01

    This paper comprises kinetics of chemical reaction or rather chemisorption of uranium hexafluoride gas on sodium fluoride pellets. The chemisorption is essentially irreversible at room temperature, while the process reverses at high temperature above 280 deg C. This chemisorption process was experimentally conducted in static condition at room temperature and its kinetics was studied. In the experiments, practically pure UF{sub 6} was used and the effects of gas pressure and weight of NaF pellets, were studied. In this heterogenous reaction, in which diffusion through ash layer is followed by chemical reaction, the reaction part is instantaneous and is first order with respect to gas concentration. Since the process of chemisorption is not only pure chemical reaction but also gas diffusion through ash layer, the rate constant depreciates with the percentage loading of UF{sub 6} on NaF pellets. The kinetic equation for the above process has been established for a particular size of NaF pellets and pellet porosity. (author). 5 refs., 3 figs., 3 tabs.

  14. Fluoride release and recharge abilities of contemporary fluoride-containing restorative materials and dental adhesives.

    Science.gov (United States)

    Dionysopoulos, Dimitrios; Koliniotou-Koumpia, Eugenia; Helvatzoglou-Antoniades, Maria; Kotsanos, Nikolaos

    2013-01-01

    The aim of this study was to evaluate the fluoride release of five fluoride-releasing restorative materials and three dental adhesives, before and after NaF solution treatment. Five restorative materials (Fuji IX GP, GC Corp.; Ketac N100, 3M ESPE; Dyract Extra, Dentsply; Beautifil II, Shofu Inc.; Wave, SDI) and three dental adhesives (Stae, SDI; Fluorobond II - Shofu Inc.; Prime & Bond NT, Dentsply) were investigated before and after NaF solution treatment. A fluoride ion-selective electrode was to measure fluoride concentrations. During the 86-day period before NaF solution treatment, Fuji IX GP released the highest amount of fluoride among the restorative materials while Prime & Bond NT was the highest among the dental adhesives. After NaF solution treatment, Fuji IX GP again ranked the highest in fluoride release among the restorative materials while Fluorobond II ranked the highest among dental adhesives. It was concluded that the compositions and setting mechanisms of fluoride-containing dental materials influenced their fluoride release and recharge abilities.

  15. Effect of titanium tetrafluoride, amine fluoride and fluoride varnish on enamel erosion in vitro

    NARCIS (Netherlands)

    Vieira, A; Ruben, JL; Huysmans, MCDNJM

    2005-01-01

    This study aimed at evaluating the effect of 1 and 4% titanium tetrafluoride (TiF4) gels, amine fluoride (AmF) 1 and 0.25% and a fluoride varnish (FP) on the prevention of dental erosion. Two experimental groups served as controls, one with no pretreatment and another one pre-treated with a

  16. Daily Fluoride Intake from Iranian Green Tea: Evaluation of Various Flavorings on Fluoride Release

    Directory of Open Access Journals (Sweden)

    Afshin Maleki

    2016-01-01

    Full Text Available With increased awareness of the health benefits of the compounds in green tea, especially polyphenols, its consumption is rising. The main purpose of this study is to determine the effect of different additives on the released fluoride into tea liquor and also daily fluoride intake. The concentrations of fluoride, nitrate, sulfate, and chloride were measured in 15 different flavored green teas (Refah-Lahijan. The fluoride and other anion concentrations were measured by ion chromatography method. The data were analyzed with Statistical Package for the Social Sciences version 16.0. The results showed that the minimum and maximum concentrations of fluoride in the green tea infusions were 0.162 mg/L (cinnamon-flavored green tea and 3.29 mg/L (bagged peach-flavored green tea, respectively. The mean concentration of fluoride in the green tea leaves was 52 mg/kg, and approximately 89% of the fluoride was released from the green tea leaves into the infusions after brewing. The fluoride concentrations varied significantly among the examined green teas ( P 0.05. Finally, drinking of the studied green teas cannot make a significant contribution to the daily dietary intake of F for consumers.

  17. Fluoride release, recharge and flexural properties of polymethylmethacrylate containing fluoridated glass fillers.

    Science.gov (United States)

    Al-Bakri, I A; Swain, M V; Naoum, S J; Al-Omari, W M; Martin, E; Ellakwa, A

    2014-06-01

    The purpose of this study was to investigate the effect of fluoridated glass fillers on fluoride release, recharge and the flexural properties of modified polymethylmethacrylate (PMMA). Specimens of PMMA denture base material with various loading of fluoridated glass fillers (0%, 1%, 2.5%, 5% and 10% by weight) were prepared. Flexural properties were evaluated on rectangular specimens (n = 10) aged in deionized water after 24 hours, 1 and 3 months. Disc specimens (n = 10) were aged for 43 days in deionized water and lactic acid (pH 4.0) and fluoride release was measured at numerous intervals. After ageing, specimens were recharged and fluoride re-release was recorded at 1, 3 and 7 days after recharge. Samples containing 2.5%, 5% and 10% glass fillers showed significantly (p glass fillers specimens. All experimental specimens exhibited fluoride release in both media. The flexural strength of specimens decreased in proportion to the percentage filler inclusion with the modulus of elasticity values remaining within ISO Standard 1567. The modified PMMA with fluoridated glass fillers has the ability to release and re-release fluoride ion. Flexural strength decreased as glass filler uploading increased. © 2014 Australian Dental Association.

  18. Fluoride release and cariostatic potential of orthodontic adhesives with and without daily fluoride rinsing.

    NARCIS (Netherlands)

    Chin, M.Y.; Sandham, A.; Rumachik, E.N.; Ruben, J.L.; Huysmans, M.C.D.N.J.M.

    2009-01-01

    INTRODUCTION: In this study, we aimed to evaluate the fluoride-release profiles and caries lesion development in an enamel model with brackets cemented with 4 orthodontic adhesives with and without daily fluoride exposure. METHODS: Four orthodontic adhesives (Ketac Cem mu, 3M ESPE, Seefeld, Germany;

  19. Fluoride release and cariostatic potential of orthodontic adhesives with and without daily fluoride rinsing

    NARCIS (Netherlands)

    Chin, Yeen; Sandham, John; Rumachik, Elena N.; Ruben, Jan L.; Huysmans, Marie-Charlotte D. N. J. M.

    2009-01-01

    Introduction: In this study, we aimed to evaluate the fluoride-release profiles and caries lesion development in an enamel model with brackets cemented with 4 orthodontic adhesives with and without daily fluoride exposure. Methods: Four orthodontic adhesives (Ketac Cem mu, 3M ESPE, Seefeld, Germany;

  20. Polyelectrolyte complex formation and stability when mixing polyanions and polycations in salted media: A model study related to the case of body fluids

    Czech Academy of Sciences Publication Activity Database

    Etrych, Tomáš; Leclercq, L.; Boustta, M.; Vert, M.

    2005-01-01

    Roč. 25, 1-2 (2005), s. 281-288 ISSN 0928-0987 EU Projects: European Commission(XE) 512087 - GIANT Institutional research plan: CEZ:AV0Z40500505 Keywords : polyelectrolyte complex * selectivity * light scattering Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.347, year: 2005

  1. Oral fluoride levels 1 h after use of a sodium fluoride rinse: effect of sodium lauryl sulfate.

    Science.gov (United States)

    Vogel, Gerald L; Schumacher, Gary E; Chow, Laurence C; Tenuta, Livia M A

    2015-01-01

    Increasing the concentration of free fluoride in oral fluids is an important goal in the use of topical fluoride agents. Although sodium lauryl sulfate (SLS) is a common dentifrice ingredient, the influence of this ion on plaque fluid and salivary fluid fluoride has not been examined. The purpose of this study was to investigate the effect of SLS on these parameters and to examine the effect of this ion on total (or whole) plaque fluoride, an important source of plaque fluid fluoride after a sufficient interval following fluoride administration, and on total salivary fluoride, a parameter often used as a surrogate measure of salivary fluid fluoride. Ten subjects accumulated plaque for 48 h before rinsing with a 12 mmol/l NaF (228 µg/g F) rinse containing or not containing 0.5% (w/w) SLS. SLS had no statistically significant effect on total plaque and total saliva fluoride but significantly increased salivary fluid and plaque fluid fluoride (by 147 and 205%, respectively). These results suggest that the nonfluoride components of topical agents can be manipulated to improve the fluoride release characteristics from oral fluoride reservoirs and that statistically significant change may be observed in plaque fluid and salivary fluid fluoride concentrations that may not be observed in total plaque and total saliva fluoride concentrations.

  2. Widespread genetic switches and toxicity resistance proteins for fluoride.

    Science.gov (United States)

    Baker, Jenny L; Sudarsan, Narasimhan; Weinberg, Zasha; Roth, Adam; Stockbridge, Randy B; Breaker, Ronald R

    2012-01-13

    Most riboswitches are metabolite-binding RNA structures located in bacterial messenger RNAs where they control gene expression. We have discovered a riboswitch class in many bacterial and archaeal species whose members are selectively triggered by fluoride but reject other small anions, including chloride. These fluoride riboswitches activate expression of genes that encode putative fluoride transporters, enzymes that are known to be inhibited by fluoride, and additional proteins of unknown function. Our findings indicate that most organisms are naturally exposed to toxic levels of fluoride and that many species use fluoride-sensing RNAs to control the expression of proteins that alleviate the deleterious effects of this anion.

  3. Preliminary model validation for integral stability behavior in molten salt natural circulation

    International Nuclear Information System (INIS)

    Cai Chuangxiong; He Zhaozhong; Chen Kun

    2017-01-01

    Passive safety system is an important characteristic of Fluoride-Salt-Cooled High-Temperature Reactor (FHR). In order to remove the decay heat, a direct reactor auxiliary cooling system (DRACS) which uses the passive safety technology is proposed to the FHR as the ultimate heat sink. The DRACS is relying on the natural circulation, so the study of molten salt natural circulation plays an important role at TMSR. A high-temperature molten salt natural circulation test loop has been designed and constructed at the TMSR center of the Chinese Academy of Sciences (CAS) to understand the characteristics of the natural circulation and verify the design model. It adopts nitrate salt as the working fluid to simulate fluoride salts, and uses air as the ultimate heat sink. The test shows the operation very well and has a very nice performance, the Heat transfer coefficients (salt-salt or salt-air), power of the loop, heat loss of molten salt pool (or molten salt pipe or air cooling tower), starting time of the loop, flow rate that can be verified in this loop. A series of experiments have been done and the results show that the experimental data are well matched with the design data. This paper aims at analyzing the molten salt circulation model, studying the characteristics of the natural circulation, and verifying the Integral stability behavior by three different natural circulation experiments. Also, the experiment is going on, and more experiments will been carry out to study the molten salt natural circulation for optimizing the design. (author)

  4. Influence of the method of fluoride administration on toxicity and fluoride concentrations in Japanese quail

    Science.gov (United States)

    Fleming, W.J.; Schuler, C.A.

    1988-01-01

    Young Japanese quail (Coturnix japonica) were administered NaF for 16 d either in their diet or by esophageal intubation. Based on the total fluoride ion (Emg F-) intake over the l6-d experimental period, fluoride administered by intubation was at least six times more toxic than that fed in the diet. Dietary concentrations of 1,000 ppm F- (Emg F- for 16 d = approx. 144) produced no mortality, whereas intubated doses produced 73% or greater mortality in all groups administered 54 mg F- /kg/d or more (Emg F- for 16 d _ approx. 23 mg). GraphIc companson of the regression of log F- ppm in femurs/mg F- intake showed that fluoride levels in the femurs of quail administered fluoride by intubation were higher than in those administered fluoride in the diet.

  5. Measurement of solubility of plutonium trifluoride and rare-earth fluorides in molten LiF-BeF2-ZrF4

    International Nuclear Information System (INIS)

    Naumov, V.S.; Bychkov, A.V.; Kormilitsyn, M.V.

    1996-12-01

    Data on behavior of plutonium fluoride and fission products (FP) dissolved in fuel composition are needed to calculate the duration of an operating cycle of the ADTT facility (Accelerator-Driver Transmutation Technologies) and to determine the effect of their equilibrium concentrations on nuclear-physical characteristics of reactor operation. The data on the FP fluoride solubility in the molten salts are of great important for some industrial processes (electrolytical metal deposition, development of physical-chemical mean for processes of chemical technology, etc.) As noted above, some information on this question is given in monography and articles. Data concerning fluoride salts are given in reports. However, it was impossible to make the substantial analysis of mutual solubility of fluoride melts. The primary investigation of CeF 3 and neodymium, samarium and lanthanum fluorides showed that the solubility of the melt LiF-BeF 2 and LiF-BeF 2 -ThF 4 was a linear function of reverse temperature and increases from lanthanum to samarium in the row of rare-earth elements. Disagreement in estimation of plutonium trifluoride solubility and incomplete data on the solubility of rare-earth elements prompted this study

  6. [Historical roles of salt].

    Science.gov (United States)

    Ritz, E; Ritz, C

    2004-12-17

    Recently increasing evidence has been provided pointing to a close relation of salt consumption to hypertension as well as to target organ damage. It is interesting to note that the discussion concerning salt is unusually emotional. This may be explained, at least in part, by the fact that since ancient times salt had deep symbolic significance, as exemplified, mostly subconsciously, by many customs and expressions still in current use. In the past salt was essential to preserve food. The past importance of salt as a commodity can well be compared with that of oil today. These and further historical aspects of the role of salt are briefly dealt with in this article.

  7. Engineering Database of Liquid Salt Thermophysical and Thermochemical Properties

    Energy Technology Data Exchange (ETDEWEB)

    Manohar S. Sohal; Matthias A. Ebner; Piyush Sabharwall; Phil Sharpe

    2010-03-01

    The purpose of this report is to provide a review of thermodynamic and thermophysical properties of candidate molten salt coolants, which may be used as a primary coolant within a nuclear reactor or heat transport medium from the Next Generation Nuclear Plant (NGNP) to a processing plant, for example, a hydrogen-production plant. Thermodynamic properties of four types of molten salts, including LiF-BeF2 (67 and 33 mol%, respectively; also known as FLiBe), LiF-NaF-KF (46.5, 11.5, and 52 mol%, also known as FLiNaK), and KCl-MgCl2 (67 and 33 mol%), and sodium nitrate-sodium nitrite-potassium nitrate (NaNO3–NaNO2–KNO3, (7-49-44 or 7-40-53 mol%) have been investigated. Limitations of existing correlations to predict density, viscosity, specific heat capacity, surface tension, and thermal conductivity, were identified. The impact of thermodynamic properties on the heat transfer, especially Nusselt number was also discussed. Stability of the molten salts with structural alloys and their compatibility with the structural alloys was studied. Nickel and alloys with dense Ni coatings are effectively inert to corrosion in fluorides but not so in chlorides. Of the chromium containing alloys, Hastelloy N appears to have the best corrosion resistance in fluorides, while Haynes 230 was most resistant in chloride. In general, alloys with increasing carbon and chromium content are increasingly subject to corrosion by the fluoride salts FLiBe and FLiNaK, due to attack and dissolution of the intergranular chromium carbide. Future research to obtain needed information was identified.

  8. Reactor chemical considerations of the accelerator molten-salt breeders

    International Nuclear Information System (INIS)

    Furukawa, Kazuo; Kato, Yoshio; Ohno, Hideo; Ohmichi, Toshihiko

    1982-01-01

    A single phase of the molten fluoride mixture is simultaneously functionable as a nuclear reaction medium, a heat medium and a chemical processing medium. Applying this characteristics of molten salts, the single-fluid type accelerator molten-salt breeder (AMSB) concept was proposed, in which 7 LiF-BeF 2 -ThF 4 was served as a target-and-blanket salt (Fig. 1 and Table 1), and the detailed discussion on the chemical aspects of AMSB are presented (Tables 2 -- 4 and Fig.2). Owing to the small total amount of radiowaste and the low concentrations of each element in target salt, AMSB would be chemically managable. The performance of the standard-type AMSB is improved by adding 0.3 -- 0.8 m/o 233 UF 4 as follows(Tables 1 and 4, and Figs. 2 and 3): (a) this ''high-gain'' type AMSB is feasible to design chemically, in which still only small amount of radiowaste is included ; (b) the fissile material production rate will be increased significantly; (c) this target salt is straightly fed as an 233 U additive to the fuel of molten-salt converter reactor (MSCR) ; (d) the dirty fuel salt suctioned from MSCR is batch-reprocessed in the safeguarded regional center, in which many AMSB are facilitated ; (e) the isolated 233 UF 4 is blended in the target salt sent to many MSCRs, and the cleaned residual fertile salt is used as a diluent of AMSB salt ; (f) this simple and rational thorium fuel breeding cycle system is also suitable for the nuclear nonproliferation and for the fabrication of smaller size power-stations. (author)

  9. Molten Salt Fuel Cycle Requirements for ADTT Applications

    International Nuclear Information System (INIS)

    Del Cul, G.D.; Toth, L.M.; Williams, D.F.

    1999-01-01

    The operation of an ADT system with the associated nuclear reactions has a profound effect upon the chemistry of the fuel - especially with regards to container compatibility and the chemical separations that may be required. The container can be protected by maintaining the redox chemistry within a relatively narrow, non-corrosive window. Neutron economy as well as other factors require a sophisticated regime of fission product separations. Neither of these control requirements has been demonstrated on the scale or degree of sophistication necessary to support an ADT device. We review the present situation with respect to fluoride salts, and focus on the critical issues in these areas which must be addressed. One requirement for advancement in this area - a supply of suitable materials - will soon be fulfilled by the remediation of ORNLs Molten Salt Reactor Experiment, and the removal of a total of 11,000 kg of enriched (Li-7 > 99.9%) coolant, flush, and fuel salts

  10. A new cell for high temperature EXAFS measurements in molten rare earth fluorides

    International Nuclear Information System (INIS)

    Rollet, Anne-Laure; Bessada, Catherine; Auger, Yannick; Melin, Philippe; Gailhanou, Marc; Thiaudiere, Dominique

    2004-01-01

    A new cell with simple design has been developed for high temperature X-rays absorption measurements in both solid and molten lanthanide fluorides. Two plates of pyrolitic boron nitride are fixed hermetically together around the samples in order to avoid any evaporation and atmosphere interaction. EXAFS spectra of molten mixtures of LiF-LaF 3 measured at the La L III absorption edge are reported up to 900 deg C, and show the ability of this cell to keep the salt and to perform long time acquisition improving the signal to noise ratio

  11. The titanium tris-anilide cation [Ti(N[(t)Bu]Ar)3](+) stabilized as its perfluoro-tetra-phenylborate salt: structural characterization and synthesis in connection with redox activity of 4,4'-bipyridine dititanium complexes.

    Science.gov (United States)

    Spinney, Heather A; Clough, Christopher R; Cummins, Christopher C

    2015-04-21

    This work explores the reduction of 4,4'-bipyridine using two equivalents of the titanium(iii) complex Ti(N[(t)Bu]Ar)3 resulting in formation of a black, crystalline complex, (4,4'-bipy){Ti(N[(t)Bu]Ar)3}2, for which an X-ray structure determination is reported. The neutral, black, 4,4'-bipyridine-bridged bimetallic was found to be redox active, with mono- and di-anions being accessible electrochemically, and with the mono- and di-cations also being accessible chemically, and isolable, at least when using the weakly coordinating anion [B(C6F5)4](-) as the counter-ion. It proved possible to crystallize the salt [(4,4'-bipy){Ti(N[(t)Bu]Ar)3}2][B(C6F5)4]2 for a single-crystal X-ray structure investigation; in this instance it was revealed that the aromaticity of the 4,4'-bipyridine ligand, that had been disrupted upon reduction, had been regained. A rare cationic d(0) metal tris-amide complex, shown by X-ray crystallography to contain an intriguing pyramidal TiN3 core geometry, namely {Ti(N[(t)Bu]Ar)3}(+), could also be isolated when using [B(C6F5)4] as the essentially non-interacting counter-ion. This highly reactive cation should be considered as a potential intermediate in the plethora of reactions wherein Ti(N[(t)Bu]Ar)3 has been shown to effect the reduction of substrates including halogenated organic molecules, carbonyl compounds, organic nitriles, and metal complexes.

  12. A road map for the realization of global-scale thorium breeding fuel cycle by single molten-fluoride flow

    International Nuclear Information System (INIS)

    Furukawa, K.; Arakawa, K.; Erbay, L. B.

    2007-01-01

    For global survival in this century, we urgently need to launch a completely new global nuclear fission industry. To get worldwide public acceptance of nuclear energy, improvements are essential not only on safety, radio-waste management and economy but also especially nuclear proliferation resistance and safeguards. However, such global fission industry cannot replace the present fossil fuel industry in the next 50 years, unless the doubling-time of nuclear energy is less than 10 years, preferably 5-7 years. Such a doubling-time cannot be established by any kind of classical 'Fission Breeding Power Station' concept. We need a symbiotic system which couples fission power reactors with a system which can convert fertile thorium to fissile U-233, such as a spallation or D/T fusion (if and when it becomes available). For such a purpose, THORIMS-NES [Thorium Molten-Salt Nuclear Energy Synergetic System] has been proposed, which is composed of simple thermal fission power stations (FUJI) and fissile producing Accelerator Molten-Salt Breeder (AMSB). Its system functions are very ambitious, delicate and complex, but can be realized in the form of simple hardware applying the multifunctional 'single-phase molten-fluoride' circulation system. This system has no difficulties relating with 'radiation-damage', 'heat-removal' and 'chemical processing' owing to the simple 'idealistic ionic liquid' character. FUJI is size-flexible (economical even in smaller sizes), fuel self-sustaining without any continuous chemical processing and without core-graphite replacement, and AMSB is based on a single-fluid molten-salt target/blanket concept, which solves most engineering difficulties such as radiation-damage, heat-removal etc., except high-current proton accelerator development. Several AMSBs are accommodated in the regional centers (several ten sites in the world) with batch chemical processing plants including radio-waste management. The integrated thorium breeding fuel cycle is

  13. Covalent attachment of pyridine-type molecules to glassy carbon surfaces by electrochemical reduction of in situ generated diazonium salts. Formation of ruthenium complexes on ligand-modified surfaces

    International Nuclear Information System (INIS)

    Yesildag, Ali; Ekinci, Duygu

    2010-01-01

    In this study, pyridine, quinoline and phenanthroline molecules were covalently bonded to glassy carbon (GC) electrode surfaces for the first time using the diazonium modification method. Then, the complexation ability of the modified films with ruthenium metal cations was investigated. The derivatization of GC surfaces with heteroaromatic molecules was achieved by electrochemical reduction of the corresponding in situ generated diazonium salts. X-ray photoelectron spectroscopy (XPS) was used to confirm the attachment of heteroaromatic molecules to the GC surfaces and to determine the surface concentration of the films. The barrier properties of the modified GC electrodes were studied in the presence of redox probes such as Fe(CN) 6 3- and Ru(NH 3 ) 6 3+ by cyclic voltammetry. Additionally, the presence of the resulting organometallic films on the surfaces was verified by XPS after the chemical transformation of the characterized ligand films to the ruthenium complex films. The electrochemical behavior of these films in acetonitrile solution was investigated using voltammetric methods, and the surface coverage of the organometallic films was determined from the reversible metal-based Ru(II)/Ru(III) oxidation waves.

  14. Covalent attachment of pyridine-type molecules to glassy carbon surfaces by electrochemical reduction of in situ generated diazonium salts. Formation of ruthenium complexes on ligand-modified surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Yesildag, Ali [Department of Chemistry, Faculty of Sciences, Atatuerk University, 25240 Erzurum (Turkey); Ekinci, Duygu, E-mail: dekin@atauni.edu.t [Department of Chemistry, Faculty of Sciences, Atatuerk University, 25240 Erzurum (Turkey)

    2010-09-30

    In this study, pyridine, quinoline and phenanthroline molecules were covalently bonded to glassy carbon (GC) electrode surfaces for the first time using the diazonium modification method. Then, the complexation ability of the modified films with ruthenium metal cations was investigated. The derivatization of GC surfaces with heteroaromatic molecules was achieved by electrochemical reduction of the corresponding in situ generated diazonium salts. X-ray photoelectron spectroscopy (XPS) was used to confirm the attachment of heteroaromatic molecules to the GC surfaces and to determine the surface concentration of the films. The barrier properties of the modified GC electrodes were studied in the presence of redox probes such as Fe(CN){sub 6}{sup 3-} and Ru(NH{sub 3}){sub 6}{sup 3+} by cyclic voltammetry. Additionally, the presence of the resulting organometallic films on the surfaces was verified by XPS after the chemical transformation of the characterized ligand films to the ruthenium complex films. The electrochemical behavior of these films in acetonitrile solution was investigated using voltammetric methods, and the surface coverage of the organometallic films was determined from the reversible metal-based Ru(II)/Ru(III) oxidation waves.

  15. Emissions of fluorides from welding processes.

    Science.gov (United States)

    Szewczyńska, Małgorzata; Pągowska, Emilia; Pyrzyńska, Krystyna

    2015-11-01

    The levels of fluoride airborne particulates emitted from welding processes were investigated. They were sampled with the patented IOM Sampler, developed by J. H. Vincent and D. Mark at the Institute of Occupational Medicine (IOM), personal inhalable sampler for simultaneous collection of the inhalable and respirable size fractions. Ion chromatography with conductometric detection was used for quantitative analysis. The efficiency of fluoride extraction from the cellulose filter of the IOM sampler was examined using the standard sample of urban air particle matter SRM-1648a. The best results for extraction were obtained when water and the anionic surfactant N-Cetyl-N-N-N-trimethylammonium bromide (CTAB) were used in an ultrasonic bath. The limits of detection and quantification for the whole procedure were 8μg/L and 24μg/L, respectively. The linear range of calibration was 0.01-10mg/L, which corresponds to 0.0001-0.1mg of fluorides per m(3) in collection of a 20L air sample. The concentration of fluorides in the respirable fraction of collected air samples was in the range of 0.20-1.82mg/m(3), while the inhalable fraction contained 0.23-1.96mg/m(3) of fluorides during an eight-hour working day in the welding room. Copyright © 2015. Published by Elsevier B.V.

  16. Thermodynamic data-base for metal fluorides

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Jae Hyung; Lee, Byung Gik; Kang, Young Ho and others

    2001-05-01

    This study is aimed at collecting useful data of thermodynamic properties of various metal fluorides. Many thermodynamic data for metal fluorides are needed for the effective development, but no report of data-base was published. Accordingly, the objective of this report is to rearrange systematically the existing thermodynamic data based on metal fluorides and is to use it as basic data for the development of pyrochemical process. The physicochemical properties of various metal fluorides and metals were collected from literature and such existing data base as HSC code, TAPP code, FACT code, JANAF table, NEA data-base, CRC handbook. As major contents of the thermodynamic data-base, the physicochemical properties such as formation energy, viscosity, density, vapor pressure, etc. were collected. Especially, some phase diagrams of eutectic molten fluorides are plotted and thermodynamic data of liquid metals are also compiled. In the future, the technical report is to be used as basic data for the development of the pyrochemical process which is being carried out as a long-term nuclear R and D project.

  17. Thermodynamic data-base for metal fluorides

    International Nuclear Information System (INIS)

    Yoo, Jae Hyung; Lee, Byung Gik; Kang, Young Ho and others

    2001-05-01

    This study is aimed at collecting useful data of thermodynamic properties of various metal fluorides. Many thermodynamic data for metal fluorides are needed for the effective development, but no report of data-base was published. Accordingly, the objective of this report is to rearrange systematically the existing thermodynamic data based on metal fluorides and is to use it as basic data for the development of pyrochemical process. The physicochemical properties of various metal fluorides and metals were collected from literature and such existing data base as HSC code, TAPP code, FACT code, JANAF table, NEA data-base, CRC handbook. As major contents of the thermodynamic data-base, the physicochemical properties such as formation energy, viscosity, density, vapor pressure, etc. were collected. Especially, some phase diagrams of eutectic molten fluorides are plotted and thermodynamic data of liquid metals are also compiled. In the future, the technical report is to be used as basic data for the development of the pyrochemical process which is being carried out as a long-term nuclear R and D project

  18. Sea Salt vs. Table Salt: What's the Difference?

    Science.gov (United States)

    ... and healthy eating What's the difference between sea salt and table salt? Answers from Katherine Zeratsky, R.D., L.D. The main differences between sea salt and table salt are in their taste, texture ...

  19. Gramicidin D enhances the antibacterial activity of fluoride.

    Science.gov (United States)

    Nelson, James W; Zhou, Zhiyuan; Breaker, Ronald R

    2014-07-01

    Fluoride is a toxic anion found in many natural environments. One of the major bacterial defenses against fluoride is the cell envelope, which limits passage of the membrane-impermeant fluoride anion. Accordingly, compounds that enhance the permeability of bacterial membranes to fluoride should also enhance fluoride toxicity. In this study, we demonstrate that the pore-forming antibiotic gramicidin D increases fluoride uptake in Bacillus subtilis and that the antibacterial activity of this compound is potentiated by fluoride. Polymyxin B, another membrane-targeting antibiotic with a different mechanism of action, shows no such improvement. These results, along with previous findings, indicate that certain compounds that destabilize bacterial cell envelopes can enhance the toxicity of fluoride. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Potential fluoride toxicity from oral medicaments: A review

    Directory of Open Access Journals (Sweden)

    Rizwan Ullah

    2017-08-01

    Full Text Available The beneficial effects of fluoride on human oral health are well studied. There are numerous studies demonstrating that a small amount of fluoride delivered to the oral cavity decreases the prevalence of dental decay and results in stronger teeth and bones. However, ingestion of fluoride more than the recommended limit leads to toxicity and adverse effects. In order to update our understanding of fluoride and its potential toxicity, we have described the mechanisms of fluoride metabolism, toxic effects, and management of fluoride toxicity. The main aim of this review is to highlight the potential adverse effects of fluoride overdose and poorly understood toxicity. In addition, the related clinical significance of fluoride overdose and toxicity has been discussed.

  1. Potential fluoride toxicity from oral medicaments: A review.

    Science.gov (United States)

    Ullah, Rizwan; Zafar, Muhammad Sohail; Shahani, Nazish

    2017-08-01

    The beneficial effects of fluoride on human oral health are well studied. There are numerous studies demonstrating that a small amount of fluoride delivered to the oral cavity decreases the prevalence of dental decay and results in stronger teeth and bones. However, ingestion of fluoride more than the recommended limit leads to toxicity and adverse effects. In order to update our understanding of fluoride and its potential toxicity, we have described the mechanisms of fluoride metabolism, toxic effects, and management of fluoride toxicity. The main aim of this review is to highlight the potential adverse effects of fluoride overdose and poorly understood toxicity. In addition, the related clinical significance of fluoride overdose and toxicity has been discussed.

  2. comparative study of fluoride in alcornea cordifolia and commercial

    African Journals Online (AJOL)

    Quantum

    2013-07-31

    Jul 31, 2013 ... fluoride than the tender stem. Hence, the hard stem is a cheap source of fluoride when compared to commercial ... The importance of addition of 10% zinc .... 1st edition, Prentice Hall, Education Limited, Publisher, Edinburgh.

  3. State and National Water Fluoridation System (Public Water Systems)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Water Fluoridation Reporting System (WFRS) has been developed to provide tools to assist states in managing fluoridation programs. WFRS is designed to track all...

  4. Low-salt diet

    Science.gov (United States)

    Low-sodium diet; Salt restriction ... control many functions. Too much sodium in your diet can be bad for you. For most people, ... you limit salt. Try to eat a balanced diet. Buy fresh vegetables and fruits whenever possible. They ...

  5. Volcano crisis response at Yellowstone volcanic complex - after-action report for exercise held at Salt Lake City, Utah, November 15, 2011

    Science.gov (United States)

    Pierson, Thomas C.; Driedger, Carolyn L.; Tilling, Robert I.

    2013-01-01

    A functional tabletop exercise was run on November 14-15, 2011 in Salt Lake City, Utah, to test crisis response capabilities, communication protocols, and decision-making by the staff of the multi-agency Yellowstone Volcano Observatory (YVO) as they reacted to a hypothetical exercise scenario of accelerating volcanic unrest at the Yellowstone caldera. The exercise simulated a rapid build-up of seismic activity, ground deformation, and hot-spring water-chemistry and temperature anomalies that culminated in a small- to moderate-size phreatomagmatic eruption within Yellowstone National Park. The YVO scientific team's responses to the unfolding events in the scenario and to simulated requests for information by stakeholders and the media were assessed by (a) the exercise organizers; (b) several non-YVO scientists, who observed and queried participants, and took notes throughout the exercise; and (c) the participants themselves, who kept logs of their actions during the exercise and later participated in a group debriefing session and filled out detailed questionnaires. These evaluations were tabulated, interpreted, and summarized for this report, and on the basis of this information, recommendations have been made. Overall, the YVO teams performed their jobs very well. The exercise revealed that YVO scientists were able to successfully provide critical hazards information, issue information statements, and appropriately raise alert levels during a fast-moving crisis. Based on the exercise, it is recommended that several measures be taken to increase YVO effectiveness during a crisis: 1. Improve role clarification within and between YVO science teams. 2. Improve communications tools and protocols for data-sharing and consensus-building among YVO scientists, who are geographically and administratively dispersed among various institutions across the United States. 3. Familiarize YVO staff with Incident Command System (ICS) procedures and protocols, and provide more in

  6. Molten salt breeder reactor

    International Nuclear Information System (INIS)

    1977-01-01

    MSBR Study Group formed in October 1974 has studied molten salt breeder reactor and its various aspects. Usage of a molten salt fuel, extremely interesting as reactor chemistry, is a great feature to MSBR; there is no need for separate fuel making, reprocessing, waste storage facilities. The group studied the following, and these results are presented: molten salt technology, molten salt fuel chemistry and reprocessing, reactor characteristics, economy, reactor structural materials, etc. (Mori, K.)

  7. A simple and colorimetric fluoride receptor and its fluoride-responsive organogel

    Energy Technology Data Exchange (ETDEWEB)

    Yu Xudong, E-mail: 081022009@fudan.edu.cn [College of Science, Hebei University of Science and Technology, Yuhua Road 70, Shijiazhuang 050080 (China); Li Yajuan [College of Science, Hebei University of Science and Technology, Yuhua Road 70, Shijiazhuang 050080 (China); Yin Yaobing; Yu Decai [College of Science, Hebei University of Engineering, 199 South street of Guangming, Handan 056038 (China)

    2012-08-01

    In this paper, a new p-nitrophenylhydrozine-based anion receptor 1 containing cholesterol group had been designed and synthesized. It could selectively recognize fluoride among different anions tested with color changes from pale yellow to red for visual detection. Simultaneously, it could gel in cyclohexane, and the gel was also fluoride-responsive. When treated with TBAF (tetra-n-butylammonium fluoride), the gel could undergo gel-sol transition accompanied by color, morphology and surface changes. The binding mechanism had been investigated by UV-vis and {sup 1}HNMR (proton nuclear magnetic resonance spectra) titrations. From SEM (scanning electron microscope), SAXS (small-angle X-ray scattering), IR (Infrared Spectroscopy) and CA (contact angle) experiments, it was indicated that the addition of F{sup -} could destroy the molecule assembly of host 1 in the gel state, thus resulting in the gel-to-sol transition due to the binding site competition effect. To the best of our knowledge, this was the simplest fluoride-responsive organogel with high selectivity. Highlights: Black-Right-Pointing-Pointer A novel kind receptor for selective recognition of fluoride had been designed. Black-Right-Pointing-Pointer Its organogel was also fluoride-responsive. Black-Right-Pointing-Pointer This is the simplest fluoride-responsive organogel with high selectivity.

  8. FLUORIDE: A REVIEW OF USE AND EFFECTS ON HEALTH.

    Science.gov (United States)

    Kanduti, Domen; Sterbenk, Petra; Artnik, Barbara

    2016-04-01

    Appropriate oral health care is fundamental for any individual's health. Dental caries is still one of the major public health problems. The most effective way of caries prevention is the use of fluoride. The aim of our research was to review the literature about fluoride toxicity and to inform physicians, dentists and public health specialists whether fluoride use is expedient and safe. Data we used in our review were systematically searched and collected from web pages and documents published from different international institutions. Fluoride occurs naturally in our environment but we consume it in small amounts. Exposure can occur through dietary intake, respiration and fluoride supplements. The most important factor for fluoride presence in alimentation is fluoridated water. Methods, which led to greater fluoride exposure and lowered caries prevalence, are considered to be one of the greatest accomplishments in the 20th century`s public dental health. During pregnancy, the placenta acts as a barrier. The fluoride, therefore, crosses the placenta in low concentrations. Fluoride can be transmitted through the plasma into the mother's milk; however, the concentration is low. The most important action of fluoride is topical, when it is present in the saliva in the appropriate concentration. The most important effect of fluoride on caries incidence is through its role in the process of remineralization and demineralization of tooth enamel. Acute toxicity can occur after ingesting one or more doses of fluoride over a short time period which then leads to poisoning. Today, poisoning is mainly due to unsupervised ingestion of products for dental and oral hygiene and over-fluoridated water. Even though fluoride can be toxic in extremely high concentrations, it`s topical use is safe. The European Academy of Paediatric Dentistry (EAPD) recommends a preventive topical use of fluoride supplements because of their cariostatic effect.

  9. The effective use of fluorides in public health

    DEFF Research Database (Denmark)

    Jones, Sheila; Burt, Brian A; Petersen, Poul Erik

    2005-01-01

    , systematic reviews summarizing these extensive databases have indicated that water fluoridation and fluoride toothpastes both substantially reduce the prevalence and incidence of dental caries. We present four case studies that illustrate the use of fluoride in modern public health practice, focusing on......Dental caries remain a public health problem for many developing countries and for underprivileged populations in developed countries. This paper outlines the historical development of public health approaches to the use of fluoride and comments on their effectiveness. Early research...

  10. Experiments and Modeling in Support of Generic Salt Repository Science

    International Nuclear Information System (INIS)

    Bourret, Suzanne Michelle; Stauffer, Philip H.; Weaver, Douglas James; Caporuscio, Florie Andre; Otto, Shawn; Boukhalfa, Hakim; Jordan, Amy B.; Chu, Shaoping; Zyvoloski, George Anthony; Johnson, Peter Jacob

    2017-01-01

    Salt is an attractive material for the disposition of heat generating nuclear waste (HGNW) because of its self-sealing, viscoplastic, and reconsolidation properties (Hansen and Leigh, 2012). The rate at which salt consolidates and the properties of the consolidated salt depend on the composition of the salt, including its content in accessory minerals and moisture, and the temperature under which consolidation occurs. Physicochemical processes, such as mineral hydration/dehydration salt dissolution and precipitation play a significant role in defining the rate of salt structure changes. Understanding the behavior of these complex processes is paramount when considering safe design for disposal of heat-generating nuclear waste (HGNW) in salt formations, so experimentation and modeling is underway to characterize these processes. This report presents experiments and simulations in support of the DOE-NE Used Fuel Disposition Campaign (UFDC) for development of drift-scale, in-situ field testing of HGNW in salt formations.

  11. Experiments and Modeling in Support of Generic Salt Repository Science

    Energy Technology Data Exchange (ETDEWEB)

    Bourret, Suzanne Michelle [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Stauffer, Philip H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Weaver, Douglas James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Caporuscio, Florie Andre [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Otto, Shawn [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Boukhalfa, Hakim [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Jordan, Amy B. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chu, Shaoping [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Zyvoloski, George Anthony [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Johnson, Peter Jacob [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-01-19

    Salt is an attractive material for the disposition of heat generating nuclear waste (HGNW) because of its self-sealing, viscoplastic, and reconsolidation properties (Hansen and Leigh, 2012). The rate at which salt consolidates and the properties of the consolidated salt depend on the composition of the salt, including its content in accessory minerals and moisture, and the temperature under which consolidation occurs. Physicochemical processes, such as mineral hydration/dehydration salt dissolution and precipitation play a significant role in defining the rate of salt structure changes. Understanding the behavior of these complex processes is paramount when considering safe design for disposal of heat-generating nuclear waste (HGNW) in salt formations, so experimentation and modeling is underway to characterize these processes. This report presents experiments and simulations in support of the DOE-NE Used Fuel Disposition Campaign (UFDC) for development of drift-scale, in-situ field testing of HGNW in salt formations.

  12. Fluoride in dental biofilm and saliva

    DEFF Research Database (Denmark)

    Larsen, Line Staun

    Dette ph.d.-projekt bidrager med ny viden om fordelingen af fluorid i dental biofilm og saliva. For at udforske koncentrationen af fluorid i naturlig (in vivo) biofilmvæske, biofilmsediment og i saliva, blev der udført to meget forskellige kliniske studier. Resultaterne fra tværsnitsstudiet (Studie...... I), hos en stor gruppe mennesker (n=42) der konsulterede en tandklinik for behandling, bekræfter tidligere viden, at der findes en naturlig biologisk variation i fluoridkoncentrationerne i biofilm fra forskellige intra-orale regioner samt mellem biofilmvæske, biofilmsediment og saliva...... fluoridkoncentrationer i underkæbefronten, intermediære koncentrationer i alle tre overkæberegioner og de laveste koncentrationer i underkæbemolarregionerne. Begge studier viser at biofilmsedimentet indeholder størstedelen af fluorid i biofilm. Set i et bredere perspektiv viser fundene at der er et omvendt forhold...

  13. Effect of atmospheric fluoride on plant metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Suketa, Y; Yamamoto, T

    1971-05-01

    Studies on the relationship between the exposure factor and foliar deposition of fluoride, or foliar burn, are introduced. Photosynthesis is adversely affected by atmospheric fluoride. The photosynthesis of a strawberry deteriorated by 50% when the strawberry was exposed to 48 ppb hydrofluoric acid for one hour. The effect of fluoride on the respiratory organs of plants is also reported. Soy beans exposed to 0.03 ppm HF had metabolic abnormalities. The total sugar quantity of leaves decreased from 242-253 mg/100 g to 111-141 mg/100 g and the non-reduced sugar/reduced sugar ratio decreased from 4.6-8.7 to 0.8-1.6. 30 references, 3 figures, 14 tables.

  14. Uranyl fluoride luminescence in acidic aqueous solutions

    International Nuclear Information System (INIS)

    Beitz, J.V.; Williams, C.W.

    1996-01-01

    Luminescence emission spectra and decay rates are reported for uranyl species in acidic aqueous solutions containing HF or added NaF. The longest luminescence lifetime, 0.269 ± 0.006 ms, was observed from uranyl in 1 M HF + 1 M HClO 4 at 296 K and decreased with increasing temperature. Based on a luminescence dynamics model that assumes equilibrium among electronically excited uranyl fluoride species and free fluoride ion, this long lived uranyl luminescence in aqueous solution is attributed primarily to UO 2 F 2 . Studies on the effect of added LiNO 3 or Na 2 WO 4 ·2H 2 O showed relatively weak quenching of uranyl fluoride luminescence which suggests that high sensitivity determination of the UF 6 content of WF 6 gas should be feasible via uranyl luminescence analysis of hydrolyzed gas samples of impure WF 6

  15. HOUSEHOLD PURIFICATION OF FLUORIDE CONTAMINATED MAGADI (TRONA)

    DEFF Research Database (Denmark)

    Nielsen, Joan Maj; Dahi, Elian

    1997-01-01

    Purification of fluoride contaminated magadi is studied using bone char sorption and calcium precipitation. The bone char treatment is found to be workable both in columns and in batches where the magadi is dissolved in water prior to treatment. The concentrations in the solutions were 89 g magadi....../L and 95 and 400 mg F/L respectively in natural and synthetic solutions. The fluoride removal capacities observed were 4.6 mg F/g bone char for the column system and 2.7 mg F/g bone char for the batch system in case of synthetic magadi solution. It is however concluded that the batch system is the best...... treatment method. A procedure for purification of fluoride contaminated magadi at household level is described....

  16. Fluoride levels in commercially available rice in Ethiopia | Tegegne ...

    African Journals Online (AJOL)

    Alkaline fusion was used for sample preparation of six varieties for both the raw rice and rice cooked with tap water and fluoridated water. Fluoride levels ranged from 0.1-5.5 mg/kg in raw rice sample. Rice which was cooked with different fluoride levels of water showed increment depending on the method of cooking.

  17. Health effects of fluoride pollution caused by coal burning

    Energy Technology Data Exchange (ETDEWEB)

    Ando, M.; Tadano, M.; Yamamoto, S.; Tamura, K.; Chen, X. [Regional Environment Division, National Institute for Environmental Studies, Tsukuba, 305-0083 Ibaraki (Japan); Asanuma, S. [Japan Institute of Rural Medicine, Usuda, Nagano (Japan); Watanabe, T. [Saku Central Hospital, Usuda, Nagano (Japan); Kondo, T. [Matsumoto Dental College, Shiojiri, Nagano (Japan); Sakurai, S. [Otsuma Women' s University, Tama, Tokyo (Japan); Ji, R.; Liang, C.; Cao, S. [Institute of Environmental Health and Engineering, Beijing (China); Hong, Z. [Shanxi Maternity and Children' s Hospital, Taiyuan (China)

    2001-04-23

    Recently a huge amount of fluoride in coal has been released into indoor environments by the combustion of coal and fluoride pollution seems to be increasing in some rural areas in China. Combustion of coal and coal bricks is the primary source of gaseous and aerosol fluoride and these forms of fluoride can easily enter exposed food products and the human respiratory tract. Major human fluoride exposure was caused by consumption of fluoride contaminated food, such as corn, chilies and potatoes. For each diagnostic syndrome of dental fluorosis, a log-normal distribution was observed on the logarithm of urinary fluoride concentration in students in China. Urinary fluoride content was found to be a primary health indicator of the prevalence of dental fluorosis in the community. In the fluorosis areas, osteosclerosis in skeletal fluorosis patients was observed with a high prevalence. A biochemical marker of bone resorption, urinary deoxypyridinoline content was much higher in residents in China than in residents in Japan. It was suggested that bone resorption was stimulated to a greater extent in residents in China and fluoride may stimulate both bone resorption and bone formation. Renal function especially glomerular filtration rate was very sensitive to fluoride exposure. Inorganic phosphate concentrations in urine were significantly lower in the residents in fluorosis areas in China than in non-fluorosis area in China and Japan. Since airborne fluoride from the combustion of coal pollutes extensively both the living environment and food, it is necessary to reduce fluoride pollution caused by coal burning.

  18. Fluoride removal performance of phosphoric acid treated lime ...

    African Journals Online (AJOL)

    Fluoride in drinking water above permissible levels is responsible for dental and skeletal fluorosis. In this study, removal of fluoride ions from water using phosphoric acid treated lime was investigated in continuous and point-of-use system operations. In the continuous column operations, fluoride removal performance was ...

  19. Fluoride removal from aqueous solution by pumice: case study on ...

    African Journals Online (AJOL)

    The fluoride removal from synthetic water by pumice was studied at batch experiments in this study. The effect of pH, contact time, fluoride concentration and adsorbent dose on the fluoride sequestration was investigated. The optimum conditions were studied on Kuhbonan water as a case study. The results showed that ...

  20. Coprecipitation of iron and silver with barium fluoride

    International Nuclear Information System (INIS)

    Kopilova, N.V.; Khamidov, B.O.; Kashina, Z.A.; Ikrami, D.D.

    1986-01-01

    Distribution of trace contaminants of iron and silver at coprecipitation of barium fluoride is studied in present work. It is defined that iron almost completely coprecipitated with barium fluoride in wide range of ph 5.5-12. Silver coprecipitated with barium fluoride in ph range 4-7. The value of coprecipitation varies from 94% to 100%.