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Sample records for avoiding neptunium production

  1. Interaction of neptunium (7) with some oxidation products of normal and secondary alcohols

    International Nuclear Information System (INIS)

    Tananaev, I.G.

    1990-01-01

    Interaction of neptunium (7) with formaldehyde and acetone -products of methane and isopropanol oxidation in alkali medium -was studied. With increase in KOH concentration neptunium (7) reduction rate decreases. The reaction order in the range of 0.2-1.0 mol/l KOH equals -1. The reaction order with regard to reducing agent is 0.9 at acetone concentrations 0.07-0.35 mol/l and 1.0 at formaldehyde concentration 2.5-10 mmol/l. Activation energies are equal to 49±2 kJ/mol for neptunium (7) reduction by acetone and 59±4 kJ/mol - by formaldehyde. Formaldehyde is oxidized by neptunium (7) to formic acid

  2. Method of neptunium recovery into the product stream of the Purex second codecontamination step for LWR fuel reprocessing

    Energy Technology Data Exchange (ETDEWEB)

    Tsuboya, T; Nemoto, S; Hoshino, T; Segawa, T [Power Reactor and Nuclear Fuel Development Corp., Tokyo (Japan)

    1973-04-01

    The neptunium behavior in the second codecontamination step in Purex process of Power Reactor and Nuclear Fuel Development Corporation was experimentally studied, and the conditions for discharging neptunium in product stream were examined. Improved nitrous acid method was applied to the second codecontamination step. Nitrous acid (NaNO/sub 2/) was supplied to the 1st stage of extraction section at feed rate of 7.5 mM/hr, and hydrazine (hydrazine nitrate) was supplied to some stages near feed point at feed rate of 1.6 mM/hr, by using laboratory scale mixer-settlers having 6 ml of mixing volume and 17 ml of settling volume. Neptunium extraction behavior was analyzed by the code NEPTUN-I simulating neptunium concentration profile and by the code NEPTUN-II for calculating Np (V) and Np (VI) concentration. Batch experiments were performed for explaining the reduction reaction of Np (VI) in organic phase. After shaking the aqueous solution containing Np (VI) in 3 M nitric acid with the various volume ratios of TBP, both phases were separated, and the neptunium concentration was determined. In conclusion, the improved nitrous acid method was effective for the neptunium discharge in product stream when the flow ratio of organic phase to aqueous phase was increased to about three times.

  3. A method of neptunium recovery into the product stream of the Purex 1st codecontamination step for LWR fuel reprocessing

    International Nuclear Information System (INIS)

    Tsuboya, Takao; Nemoto, Shinichi; Hoshino, Tadaya; Segawa, Takeshi

    1973-01-01

    An improved nitrous acid method was applied for recovering neptunium in spent fuel. Counter-current solvent extraction has been performed to find out its recovery conditions. The nitrous acid in the form of sodium salt solution was fed to the 1st stage of extraction section, and hydrazine nitrate was fed to some stages near feed point. Flow rate and the concentration of additives were altered for finding out optimum condition. Laboratory scale mixer-settlers having 6 ml of mixing volume and 17 ml of settling volume for each stage were used. The nitrous acid method was improved so that the reduction reaction in scrub section can be eliminated by the decomposition of the nitrous acid using a reagent such as sulfamic acid, urea, or hydrazine. In operation, the feed rate of the nitrous acid was about 3 mM/hr, and about 61% of neptunium charged was discharged in the product stream of Purex-1st codecontamination step designed for the LWR fuel reprocessing plant of Power Reactor and Nuclear Fuel Development Corporation. The calculated value of Δx/x for extraction section agreed with the experimental value, where Δx is the quantity of oxidation, and x is the inventory for neptunium in each stage. In conclusion, the improved nitrous acid method is effective for the neptunium discharge in product stream, and the difference of neptunium extraction between estimate and experiment is caused by some of reduction reaction in scrub section. (Iwakiri, K.)

  4. Neptunium determination in PUREX process

    International Nuclear Information System (INIS)

    Rawat, Neetika; Kar, Aishwarya S.; Tomar, B.S.; Pandey, M.P.; Umadevi, K.

    2016-10-01

    237 Np is one of the most important minor actinides present in nuclear spent fuel both from environmental and application point of view. The routing of neptunium to the particular stream of PUREX process is necessary for its separation and purification as 237 Np is the target nuclide for production of 238 Pu. The routing of neptunium to a particular PUREX stream will also help in better nuclear waste management, which in turn, will impart less bearing on the environment considering its long half life, alpha emitting properties and mobile nature. In order to route Neptunium to a particular stream of PUREX process, it is imperative to understand the distribution of neptunium in various process streams. Owing to high dose of actual samples, the neptunium distribution was studied using 239 Np tracer by simulating actual column conditions of PUREX streams in lab scale. The present study deals with neptunium determination in actual PUREX streams samples also. (author)

  5. The measurement of neptunium in fast reactor fuel reprocessing

    International Nuclear Information System (INIS)

    Mair, M.A.; Savage, D.J.; Kyffin, T.W.

    1986-02-01

    Analytical techniques have been developed to measure neptunium in the feed, waste and product streams of a fast reactor fuel reprocessing plant. The estimated level of one microgram per milligram of plutonium in some solutions presented severe separation and measurement problems. An initial separation stage was essential, and both ion exchange and solvent extraction using thenoyltrifluoroacetone were studied. The redox chemistry of neptunium necessary to achieve good separation is considered. Spectrophotometry measurement of the stable neptunium/arsenazo III complex was selected for the final neptunium determination with additional analysis by radiometric methods. Incomplete recovery of neptunium during the separation stages necessitated yield measurements, using either neptunium-237 as an internal standard or the short lived gamma active neptunium-239 isotope as a tracer. The distribution of neptunium between the waste and product streams is discussed, in relation to the chemistry of neptunium in the reprocessing plant. (author)

  6. Study of an automatic dosing of neptunium in the industrial process of separation neptunium 237-plutonium 238

    International Nuclear Information System (INIS)

    Ros, Pierre

    1973-01-01

    The objective is to study and to adapt a method of automatic dosing of neptunium to the industrial process of separation and purification of plutonium 238, while taking the information quality and economic aspects into account. After a recall of some generalities on the production of plutonium 238, and the process of separation plutonium-neptunium, the author addresses the dosing of neptunium. The adopted measurement technique is spectrophotometry (of neptunium, of neptunium peroxide) which is the most flexible and economic to adapt to automatic control. The author proposes a project of chemical automatic machine, and discusses the complex (stoichiometry, form) and some aspects of neptunium dosing (redox reactions, process control) [fr

  7. Solubility product of tetravalent neptunium hydrous oxide and its ionic strength dependence

    Energy Technology Data Exchange (ETDEWEB)

    Fujiwara, K.; Mori, T. [Japan Nuclear Cycle Development Institute (JNC), 4-33, Muramatsu, Tokai-mura, Naka-gun, Ibaraki-ken, 319-1194 (Japan); Kohara, Y. [Inspection and Development Company, 4-33, Muramatsu, Tokaimura, Naka-gun, Ibaraki-ken, 319-1112 (Japan)

    2005-07-01

    Full text of publication follows: Solubility products (K{sub sp}) are key parameters in the context of reliable assessment of actinides migration in the repository conditions of high level radioactive waste. Neptunium (Np(IV)) is one of the most important actinide elements in the assessment, because of its inventory and the long half-life. A few previous data for Np(IV) solubility are varied widely due to experimental difficulties related to the extremely low solubility. We carried out batch-type experiments under nitrogen atmosphere using a glovebox. Np(V) was reduced to Np(III) by bubbling 0.5 ppm H{sub 2} / N{sub 2} gas through the solution for 30 days in the presence of platinum black as catalyst. After reducing treatment, the Np(III) converted to Np(IV) by auto-oxidation within approximately three days. The solubilities of the Np(IV) were measured in the pHc ranging from 2 to 4, at room temperature (23 {+-} 2 deg. C), in ionic strength(I) = 0.1, 0.5, 1.0 and 2.0 M NaClO{sub 4}. The equilibrium condition was confirmed by over-saturation and under-saturation method. After the equilibrium, the pH{sub c} and the E{sub h} value of the suspension were measured. The suspension was then filtered using a filter with a NMWL of 3000 (less than 2 nm{phi}). The Np radio activity in the filtrate was determined by alpha spectrometry and absorption spectra of Np(IV). The solubility decreased with increasing pHc and the hydrolysis species are predominantly formed. From the obtained results, the solubility products (K{sub sp}) of Np hydroxide, for the reaction, NpO{sub 2} . xH{sub 2}O {r_reversible} Np{sup 4+} + 4OH{sup -} + (x-2)H{sub 2}O, at I = 0.1, 0.5, 1.0 and 2.0 were determined by using formation constants ({beta}{sub n}(I)), which were determined for the reaction, Np{sup 4+} + nOH{sup -} {r_reversible} Np(OH){sub n}{sup (4-n)+}. By using the specific interaction theory (SIT), the solubility product of tetravalent Np hydrous oxide is calculated to be log K{sub sp}{sup 0

  8. Process chemistry of neptunium

    Energy Technology Data Exchange (ETDEWEB)

    Srinivasan, N.; Ramaniah, M. V.; Nadkarni, M. N.; Kumar, S. V.; Patil, S. K.; Ramakrishna, V. V.; Swarup, R.; Avadhany, G. V.N.; Sonawane, R. R.; Kartha, P. K.S.

    1973-07-01

    Research progress is reported on the recovery of neptunium from reprocessing of irradiated uranium. Areas considered are: use of vanadium(V) for oxidation of Np(V) to Np(VI); path of neptunium under partitioning column conditions; co-stability of Np(IV) and Pu(IV); and extraction of Np(IV) by tricaprylmethylammonium nitrate. (DHM)

  9. Neptunium (IV) oxalate solubility

    International Nuclear Information System (INIS)

    Luerkens, D.W.

    1983-07-01

    The equilibrium solubility of neptunium (IV) oxalate in nitric/oxalic acid solutions was determined at 22 0 C, 45 0 C, and 60 0 C. The concentrations of nitric/oxalic acid solutions represented a wide range of free oxalate ion concentration. A mathematical solubility model was developed which is based on the formation of the known complexes of neptunium (IV) oxalate. the solubility model uses a simplified concentration parameter which is proportional to the free oxalate ion concentration. The solubility model can be used to estimate the equilibrium solubility of neptunium (IV) oxalate over a wide range of oxalic and nitric acid concentrations at each temperature

  10. Neptunium: a bibliographic reference

    International Nuclear Information System (INIS)

    Mosley, R.E.

    1979-06-01

    A comprehensive bibliograhy of the literature on the element neptunium published prior to January 1976 is presented. A short abstract is given for each listed reference, with a few exceptions. The references are divided into sections categorized as General, Man-Made Sources (Reactors), Man-Made Sources (Fuel Reprocessing), Chemistry (Solubility), Chemistry (Compounds), Chemistry (Isotopes), Analyses (Instrumental), Analyses (Chemical), Chemical (Animal), Biological (Effects), Biological (Animal-Metabolism-Retention), Biological (Air Movement), Biological (Human Inhalation), Measurement, and Dosimetry. The bibliography contains author and keyword indexes and was compiled to serve as a quick reference source for neptunium-related work. 184 citations

  11. Biology of neptunium

    International Nuclear Information System (INIS)

    Wirth, R.E.

    1985-11-01

    This work contains detailed information about fractional absorption of neptunium through gastrointestinal tract in vivo as well as about organ and subcellular distribution in rats. Biochemical investigations have shown, that neptunium is bound to the iron transport protein transferrin in the blood serum. A long-term experiment resulted in osteosarkomincidences of 11% (0.2 mp Np-237/kg) and 36% (1 mg Np-237/kg); simultaneous the whole-body retention was measured during the natural lifespan of the animals of 2.5 years. (orig.) [de

  12. Process for neptunium analysis by absorption spectrophotometry

    International Nuclear Information System (INIS)

    Wagner, J.F.

    1987-01-01

    An aqueous solution of a neptunium compounds is treated by a reagent, preferentially a vanadyl sulfate oxidized by cerium IV ions, to obtain neptunium V by oxidation of neptunium IV and reduction of neptunium VI. The reagent is chosen for a negligible absorption at the wavelength used for neptunium V absorption spectrophotometry for instance 981 nm [fr

  13. Metabolism and toxicity of neptunium

    International Nuclear Information System (INIS)

    Nenot, J.C.

    1983-08-01

    The biological behaviour and toxicity of neptunium were studied. Neptunium was administered either intravenously or intramuscularly in rats. In contrast to other transuranium elements the distribution patterns of neptunium in the case of intravenous injection is not dependent on the physico-chemical state. Urinary excretion is high. The distribution after intramuscular injection showed a rather fast migration from the injection site. 237 Neptonium in urine was approximately equal to bone deposit. Neptunium behaviour followed that of alkaline earths rather than that of transplutonium elements

  14. Investigation of Neptunium Precipitator Cleanout Options

    International Nuclear Information System (INIS)

    Hill, B.C.

    2003-01-01

    Oxalate precipitation followed by filtration is used to prepare plutonium oxalate. Historically, plutonium oxalate has tended to accumulate in the precipitation tanks. These solids are periodically removed by flushing with concentrated (64 percent) nitric acid. The same precipitation tanks will now be used in the processing of neptunium. Literature values indicate that neptunium oxalate may not be as soluble as plutonium oxalate in nitric acid. Although a wide variety of options is available to improve neptunium oxalate solubility for precipitator flushing, most of these options are not practical for use. Many of these options require the use of incompatible or difficult to handle chemicals. Other options would require expensive equipment modifications or are likely to lead to product contamination. Based on review of literature and experimental results, the two best options for flushing the precipitator are (1) 64 percent nitric acid and (2) addition of sodium permanganate follow ed by sodium nitrite. Nitric acid is the easiest option to implement. It is already used in the facility and will not lead to product contamination. Experimental results indicate that neptunium oxalate can be dissolved in concentrated nitric acid (64 percent) at 60 degree C to a concentration of 2.6 to 5.6 grams of Np/liter after at least three hours of heating. A lower concentration (1.1 grams of Np/liter) was measured at 60 degree C after less than two hours of heating. These concentrations are acceptable for flushing if precipitator holdup is low (approximately 100-250 grams), but a second method is required for effective flushing if precipitator holdup is high (approximately 2 kilograms). The most effective method for obtaining higher neptunium concentrations is the use of sodium permanganate followed by the addition of sodium nitrite. There is concern that residual manganese from these flushes could impact product purity. Gas generation during permanganate addition is also a concern

  15. The extraction neptunium by trilaurylamine; L'extraction du neptunium par le trilaurylamine

    Energy Technology Data Exchange (ETDEWEB)

    Champion, J.; Chesne, A. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1964-07-01

    The extraction by trilaurylamine of neptunium (IV) from nitric acid and sulfuric acid-nitric acid media has been studied with the aim of developing a purification process for this element. Relative to the plutonium-neptunium separation, conditions are given for the oxidation of neptunium (IV) in sulfuric acid-nitric acid medium and data are presented on the stabilisation of the + 4 oxidation state by the organic solvent. Two procedures have been developed for the simultaneous purification of the two actinides. Both are based on the trilaurylamine extraction of the tetravalent nitrate species. The first utilises a constant redox potential fixed by Fe{sup +++} /Fe{sup ++} couple, while in the second, valencies are determined by successive addition of nitrite and ferrous ions. Gram quantities of neptunium 237 has been recovered from plutonium process solution. Alternate procedures are suggested for the chemical processing of irradiated Np{sup 237}. (authors) [French] L'extraction du neptunium par le trilaurylamine en milieu nitrique et sulfonitrique a ete etudiee dans le cadre de la recherche des procedes de purification de cet element. En vue d'effectuer la separation neptunium-plutonium on a precise d'une part les conditions d'oxydation du Np{sup 4+} en milieu sulfonitrique, d'autre part l'influence du solvant sur la stabilite des valences de ces deux elements. Deux procedes de purification simultanee des deux actinides ont ete developpes. Ils sont bases sur l'extraction du nitrate des elements tetravalents dans la trilaury lamine. Dans l'un, la solution a extraire a un potentiel redox fixe par un systeme auxiliaire (Fe{sup +++}/Fe{sup ++}), dans l'autre elle subit dans le meme extracteur des additions successives de nitrite et de fer ferreux. On decrit un essai semi-industriel de recuperation de neptunium 237 a partir de solution provenant de l'usine de production de plutonium de Marcoule. Differents schemas

  16. The extraction neptunium by trilaurylamine; L'extraction du neptunium par le trilaurylamine

    Energy Technology Data Exchange (ETDEWEB)

    Champion, J; Chesne, A [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1964-07-01

    The extraction by trilaurylamine of neptunium (IV) from nitric acid and sulfuric acid-nitric acid media has been studied with the aim of developing a purification process for this element. Relative to the plutonium-neptunium separation, conditions are given for the oxidation of neptunium (IV) in sulfuric acid-nitric acid medium and data are presented on the stabilisation of the + 4 oxidation state by the organic solvent. Two procedures have been developed for the simultaneous purification of the two actinides. Both are based on the trilaurylamine extraction of the tetravalent nitrate species. The first utilises a constant redox potential fixed by Fe{sup +++} /Fe{sup ++} couple, while in the second, valencies are determined by successive addition of nitrite and ferrous ions. Gram quantities of neptunium 237 has been recovered from plutonium process solution. Alternate procedures are suggested for the chemical processing of irradiated Np{sup 237}. (authors) [French] L'extraction du neptunium par le trilaurylamine en milieu nitrique et sulfonitrique a ete etudiee dans le cadre de la recherche des procedes de purification de cet element. En vue d'effectuer la separation neptunium-plutonium on a precise d'une part les conditions d'oxydation du Np{sup 4+} en milieu sulfonitrique, d'autre part l'influence du solvant sur la stabilite des valences de ces deux elements. Deux procedes de purification simultanee des deux actinides ont ete developpes. Ils sont bases sur l'extraction du nitrate des elements tetravalents dans la trilaury lamine. Dans l'un, la solution a extraire a un potentiel redox fixe par un systeme auxiliaire (Fe{sup +++}/Fe{sup ++}), dans l'autre elle subit dans le meme extracteur des additions successives de nitrite et de fer ferreux. On decrit un essai semi-industriel de recuperation de neptunium 237 a partir de solution provenant de l'usine de production de plutonium de Marcoule. Differents schemas utilisables lors du traitement chimique des cibles de

  17. The extraction neptunium by trilaurylamine

    International Nuclear Information System (INIS)

    Champion, J.; Chesne, A.

    1964-01-01

    The extraction by trilaurylamine of neptunium (IV) from nitric acid and sulfuric acid-nitric acid media has been studied with the aim of developing a purification process for this element. Relative to the plutonium-neptunium separation, conditions are given for the oxidation of neptunium (IV) in sulfuric acid-nitric acid medium and data are presented on the stabilisation of the + 4 oxidation state by the organic solvent. Two procedures have been developed for the simultaneous purification of the two actinides. Both are based on the trilaurylamine extraction of the tetravalent nitrate species. The first utilises a constant redox potential fixed by Fe +++ /Fe ++ couple, while in the second, valencies are determined by successive addition of nitrite and ferrous ions. Gram quantities of neptunium 237 has been recovered from plutonium process solution. Alternate procedures are suggested for the chemical processing of irradiated Np 237 . (authors) [fr

  18. Avoid Counterfeit Pesticide Products for Dogs and Cats

    Science.gov (United States)

    EPA is aware of counterfeit pet pesticides designed to look like legitimately registered pesticide products. The information on this page is intended to help consumers avoid unregistered pet products.

  19. Method of recovering neptunium from spent nuclear fuel

    International Nuclear Information System (INIS)

    Tsuboya, T.; N.

    1976-01-01

    An improved Purex wet recovery process including the step of extracting and separating uranium and plutonium simultaneously from the fission products in the presence of nitric acid and nitrous acid by using a multistage extractor unit having an extracting section and a washing section is provided for separating and recovering neptunium simultaneously with uranium and plutonium contained in spent nuclear fuel. The improved method comprises the steps of maintaining the nitrous acid concentration in said extracting section at a level suited for effecting oxidation of neptunium from (V) to (VI) valence, while lowering the nitrous acid concentration in said washing section so as to suppress reduction of neptunium from (VI) to (V) valence, and maintaining the nitric acid concentration in said washing section at a high level

  20. The organometallic chemistry of neptunium

    International Nuclear Information System (INIS)

    Bohlander, R.

    1986-09-01

    Organometallic compounds of neptunium with carbocyclic ligands (C 5 H 5 - =cp, C 8 H 8 2- =cot) have been prepared and investigated. Starting from tetrakis(cyclopentadienyle)neptunium(IV) (cp 4 Np) and tris(cyclopentadienyle)neptunium(IV) chloride (cp 3 NpCl) a lot of other Np(IV)-compounds can be obtained by ligand-exchange reactions. These have the general formula cp 3 NpL with either inorganic ionic (L=Br - , I - , 1/2SO 4 2- , NCS - , AlCl 4 - ) or organic ligands (L=NC 4 H 4 - , N 2 C 3 H 3 - , C=CH - , 1/2C= 2- , CH 3 - , C 2 H 5 - , C 6 H 5 - ). Produced by reduction, tris(cyclopentadienyle)neptunium(III), cp 3 Np) gives similar structured 1:1-adduct complexes, cp 3 Np * B, with Lewis-bases like THF, diethylether, acetonitrile. Physico-chemical properties and changes in the molecular structure of the complexes have been studied using IR-, FTIR- and optical spectroscopy (in the NIR, VIS and UV region) as well as by magnetic and EPR measurements and Moessbauer spectrometry. The results are discussed as to their classification within the actinide complex chemistry and to the comparison with lanthanide complexes. (orig./RB) [de

  1. Final report on production of Pu-238 in commercial power reactors: target fabrication, postirradiation examination, and plutonium and neptunium recovery

    International Nuclear Information System (INIS)

    Pobereskin, M.; Langendorfer, W.; Lowry, L.; Farmelo, D.; Scotti, V.; Kruger, O.

    1975-01-01

    Considerable interest has been generated in more extensive applications of radioisotope thermoelectric generator (RTG) systems. This raises questions concerning the availability of 238 Pu to supply an expanding demand. The development of much of this demand will depend upon a considerable reduction in cost of 238 Pu. Two neptunia--zirconia--fuel target rods, containing four sections each of different NpO 2 concentrations, were irradiated in the Connecticut Yankee Reactor for approximately one year. Following irradiation both target rods were subjected to nondestructive examination. One rod was chosen for destructive testing and analysis. Post-irradiation chemical analyses included total Pu and Np, ppM 236 Pu/ 238 Pu, and Pu isotopic abundance. The results of these analyses and of electron microprobe analysis which provided the relative Pu concentration across the pellet diameters are tabulated. It was concluded that the feasibility of all operations involved in the production of 238 Pu by irradiation of 237 NpO 2 targets in commercial nuclear power reactors was demonstrated and that the demonstration should be extended to a pilot-scale leading to installation of a full production capacity. (U.S.)

  2. Direct chemical reduction of neptunium oxide to neptunium metal using calcium and calcium chloride

    International Nuclear Information System (INIS)

    Squires, Leah N.; Lessing, Paul

    2016-01-01

    A process of direct reduction of neptunium oxide to neptunium metal using calcium metal as the reducing agent is discussed. After reduction of the oxide to metal, the metal is separated by density from the other components of the reaction mixture and can be easily removed upon cooling. The direct reduction technique consistently produces high purity (98%–99% pure) neptunium metal.

  3. Investigation on neptunium in a borosilicate glass

    International Nuclear Information System (INIS)

    Poirot, I.

    1988-03-01

    The oxidization state and coordination of neptunium, introduced as dopant in borosilicate glasses were studied through optical, Mossbauer spectroscopies and magnetic measurements. The neptunium oxide, introduced previously as NpO 2 is reduced during the melting process of the glass. This leads to an equilibrium in which the ratio of Np 4+ to Np 3+ valences depends on experimental conditions. Spectroscopic analysises conduct to postulate the presence of different sites for each of the oxydation states of neptunium [fr

  4. Fluorescent determination of neptunium in plutonium

    International Nuclear Information System (INIS)

    Alexandruk, V.M.; Babaev, A.S.; Dem'yanova, T.A.; Stepanov, A.V.

    1991-01-01

    This paper describes a new procedure for direct determination of Neptunium in Plutonium using laser induced time resolved fluorescence method. The procedure based on measurement of fluorescence intensity of Neptunium followed its concentration in effective layer of pellet of calcium fluoride. Detection limit of determination of Neptunium is 2 10 -12 g. At the level of Neptunium content in Plutonium more than 5 ppm relative standard deviation is equal 0.08-0.12. For carrying out of single measurement it is necessary neither more nor less 5 mkg Plutonium

  5. Avoiding tar formation in biocoke production from waste biomass

    International Nuclear Information System (INIS)

    Adrados, A.; De Marco, I.; Lopez-Urionabarrenechea, A.; Solar, J.; Caballero, B.

    2015-01-01

    This paper focuses in avoiding tar formation and in optimizing pyrolysis gas (maximizing H 2 and CO) in the production of biocoke from waste lignocellulosic biomass. In order to obtain metallurgical grade biochar (biocoke) slow heating rate and high temperature are required. Under such conditions useless pyrolysis liquids, mainly composed of water together with some heavy-sticky tars, are obtained. In order to make biocoke a cost-effective process it is necessary to optimize pyrolysis vapors avoiding tar formation and maximizing the amount and quality of both coke and gases. With this objective, in this work different heating rates (3–20 °C min −1 ) and catalysts (zeolite, Ni/CeO 2 –Al 2 O 3 ) have been tested in a two step pyrolysis process. Olive tree cuttings have been pyrolyzed in a 3.5 L batch reactor at 750 °C and the vapors generated have been thermally and catalytically treated at 900 °C in a second tubular reactor. About 25 wt.% biocoke useful as reducing agent in certain metallurgical processes, ≈57 wt.% gases with near 50 vol.% H 2 , and no tar production has been achieved when a heating rate of 3 °C min −1 and the homemade Ni/CeO 2 –Al 2 O 3 catalyst were used. - Highlights: • Metallurgical grade biochar was obtained by olive waste pyrolysis. • Low heating rates avoid tar formation and increase gas and biochar yields. • Ni/CeO 2 –Al 2 O 3 was better than HZSM5 zeolite for vapor upgrading in a second step. • Ni/CeO 2 –Al 2 O 3 and 3 °C min −1 gave the maximum H 2 , gas and biochar yields

  6. Organometallic neptunium(III) complexes

    Science.gov (United States)

    Dutkiewicz, Michał S.; Farnaby, Joy H.; Apostolidis, Christos; Colineau, Eric; Walter, Olaf; Magnani, Nicola; Gardiner, Michael G.; Love, Jason B.; Kaltsoyannis, Nikolas; Caciuffo, Roberto; Arnold, Polly L.

    2016-08-01

    Studies of transuranic organometallic complexes provide a particularly valuable insight into covalent contributions to the metal-ligand bonding, in which the subtle differences between the transuranium actinide ions and their lighter lanthanide counterparts are of fundamental importance for the effective remediation of nuclear waste. Unlike the organometallic chemistry of uranium, which has focused strongly on UIII and has seen some spectacular advances, that of the transuranics is significantly technically more challenging and has remained dormant. In the case of neptunium, it is limited mainly to NpIV. Here we report the synthesis of three new NpIII organometallic compounds and the characterization of their molecular and electronic structures. These studies suggest that NpIII complexes could act as single-molecule magnets, and that the lower oxidation state of NpII is chemically accessible. In comparison with lanthanide analogues, significant d- and f-electron contributions to key NpIII orbitals are observed, which shows that fundamental neptunium organometallic chemistry can provide new insights into the behaviour of f-elements.

  7. Organometallic neptunium(III) complexes.

    Science.gov (United States)

    Dutkiewicz, Michał S; Farnaby, Joy H; Apostolidis, Christos; Colineau, Eric; Walter, Olaf; Magnani, Nicola; Gardiner, Michael G; Love, Jason B; Kaltsoyannis, Nikolas; Caciuffo, Roberto; Arnold, Polly L

    2016-08-01

    Studies of transuranic organometallic complexes provide a particularly valuable insight into covalent contributions to the metal-ligand bonding, in which the subtle differences between the transuranium actinide ions and their lighter lanthanide counterparts are of fundamental importance for the effective remediation of nuclear waste. Unlike the organometallic chemistry of uranium, which has focused strongly on U(III) and has seen some spectacular advances, that of the transuranics is significantly technically more challenging and has remained dormant. In the case of neptunium, it is limited mainly to Np(IV). Here we report the synthesis of three new Np(III) organometallic compounds and the characterization of their molecular and electronic structures. These studies suggest that Np(III) complexes could act as single-molecule magnets, and that the lower oxidation state of Np(II) is chemically accessible. In comparison with lanthanide analogues, significant d- and f-electron contributions to key Np(III) orbitals are observed, which shows that fundamental neptunium organometallic chemistry can provide new insights into the behaviour of f-elements.

  8. The photochemistry of neptunium in aqueous perchloric acid solutions

    International Nuclear Information System (INIS)

    Friedman, H.A.; Toth, L.M.; Osborne, M.M.

    1979-01-01

    The photochemistry of neptunium ions in aqueous perchloric acid has been investigated using 254 and 300 nm UV radiation. In the absence of other reagents, Np(IV) and (V) oxidized to Np(VI), in a stepwise fashion, with individual quantum efficiencies for each step that vary from 0.02 to 0.004. Decreasing acid concentration favors the Np(IV) → Np(V) reaction whereas it hinders the Np(V) → Np(VI) photo-oxidation. When ethanol, acetaldehyde and other mild reducing agents are added to neptunium-perchloric acid solutions which are then photolyzed, the Np species are reduced to Np(III) in a stepwise fashion with individual quantum efficiencies that vary from 0.07 to 0.006. The overall photoredox reactions of neptunium are subject to competing secondary product reactions that become significant as the photolysis products accumulate. Absorption spectrophotometry was used to monitor the changes in Np oxidation states and reference spectra of the various Np oxidation states are given for 1.0 N HClO 4 . The Np species have absorption bands in the 300 to 1320 nm region that obey Beer's law only when they were properly resolved. (author)

  9. Solvent extraction of irradiated neptunium targets. I. Valence stabilization

    International Nuclear Information System (INIS)

    Thompson, G.H.; Thompson, M.C.

    1977-01-01

    Solvent extraction of 237 Np and 238 Pu from irradiated neptunium is being investigated as a possible replacement for the currently used anion exchange process at the Savannah River Plant. Solvent extraction would reduce separations costs and waste volume and increase the production rate. The major difficulty in solvent extraction processing is maintaining neptunium and plutonium in the extractable IV or VI valence states during initial extraction. This study investigated the stability of these states. Results show that: The extractable M(IV) valence states of neptunium and plutonium are mutually unstable in plant dissolver solution (2 g/l 237 Np, 0.4 g/l 238 Pu, 1.2M Al 3+ , 4.6M NO 3 - , and 1M H + ). The reaction rates producing inextractable species from extractable M(IV) or M(VI) are fast enough that greater than or equal to 99.9 percent extractable species in 237 Np-- 238 Pu mixtures cannot be maintained for a practicable processing period

  10. Determination of microamounts of neptunium by differential pulse polarography

    International Nuclear Information System (INIS)

    Cauchetier, Ph.

    1979-01-01

    Neptunium is produced in significant amounts in the ''light-water'' reactors and must be controlled at different steps of fuel reprocessing. For this purpose a method of differential pulse polarography has been developed. A tight cell containing 10 ml solution is set up in a Faraday cage. Adjustment to the tetravalent state, Np(IV), is carried out electrochemically on a mercury layer and the Np(IV) concentration is determined by differential pulse polarography, using a dropping mercury electrode. In 0.5M sulfuric acid medium, the redox potential of the reversible couple Np(IV)/Np(III) is -0.3 V/SCE. Concentrations as low as 5x10 -7 M neptunium can be measured and detection at the 2x10 -7 M level is still possible (0.5 μg in the polarographic cell). Precision is about 2% in the 10 -5 M and 10% in the 10 -6 M range. The method has been applied to aqueous and organic (TBP-dodecane) solutions. Neptunium can be determined without separation in the presence of plutonium or uranium at M/Np ratios of 10 3 and 5x10 4 , respectively. In the presence of fission products a separation is needed. (author)

  11. Determination of microamounts of neptunium by differential pulse polarography

    International Nuclear Information System (INIS)

    Cauchetier, P.

    1978-01-01

    Neptunium is produced in significant amounts in the light water reactors and must be controlled at different steps of the fuel reprocessing. For this purpose, a method of differential pulse polarography was developed. A tight cell containing 10 ml of solution is set up in a Faraday's cage. Adjustment to the tetravalent state, Np (IV), is carried out electrochemically on a mercury layer and the Np (IV) concentration is determined by differential pulse polarography, using a dropping mercury electrode. In 0,5 M sulfuric acid medium, the redox potential of the reversible system Np (IV)/Np (III) is - 0,3 V/SCE. Concentrations as low as 5.10 -7 M of neptunium can be measured and detection at the 2.10 -7 M level is still possible (0,5 μg in the polarographic cell). Precision is about 2% in the 10 -5 M and 10% in 10 -6 M range. The method has been applied to the case of aqueous and organic (TBP dodecane) solutions. Neptunium can be determined without separation in the presence of plutonium or uranium in the M/Np ratios of 10 3 and 5.10 4 respectively. In the presence of fission products a separation is needed

  12. Cyclopentadienyl uranium, neptunium and plutonium chemistry

    International Nuclear Information System (INIS)

    Plews, M.J.

    1985-01-01

    The thesis presents the preparation and characterisation of a number of mono, bis and tris(cyclopentadienyl) complexes of uranium(IV), neptunium(IV) and plutonium(IV). The work of previous studies on mono(cyclopentadienyl) thorium and uranium complexes has been extended, and a range of isostructural neptunium species isolated. Their mode of formation and stability in tetrahydrofuran and acetonitrile solutions was investigated. (author)

  13. Determination of milligram amounts of neptunium by potentiometric titration

    International Nuclear Information System (INIS)

    Ryzhinskij, M.V.; Solntseva, L.F.

    1981-01-01

    Two procedures of potentiometric titration of about 1 mg Np are reported which are based on its oxidation to neptunium (6) with silver (2) oxide followed by titration with iron (2) to neptunium (5) in one case and to neptunium (4) in the alternative one. The error is not greater than 0.2% rel. Ten-fold uranium excess does not interfere. Up to 1% of plutonium relative to neptunium does not interfere in the case of the titration to neptunium (5). In the titration to neptunium (4), plutonium is titrated stoichiometrically [ru

  14. On formation of neptunium(5) and (6) during thermal decomposition of neptunium(4) compounds

    International Nuclear Information System (INIS)

    Bessonov, A.A.; Afonas'eva, T.V.; Krot, N.N.

    1989-01-01

    A study was made on thermal behaviour of neptunium(4) peroxide (1), binary nitrate of neptunium(4) and ammonium (2), as well as neptunium(4) oxalate (3). It was established that 1 decomposed to NpO 2 in three stages with formation of neptunium(5) hydroxide at 80-100 deg C, transformed to Np 2 O 5 during further heating. The compound 2 is stable up to 150 deg C, and then decomposition, accompanied by intramolecular neptunium oxidation with formation of NH 4 NpO 2 (NO 3 ) 3 , takes place. This compound is transformed to Np 2 O 5 at 260-290 deg C. It was revealed that during 3 heating in the air at 270-330 deg C more than 70 % of metal could be transformed to pentavalent form, which was probably related with (NpO 2 ) 2 C 2 O 4 formation

  15. Speciation and solubility of neptunium in underground environments by paper electrophoresis

    International Nuclear Information System (INIS)

    Nagasaki, S.; Tanaka, Satoru; Takahashi, Yoichi

    1988-01-01

    Speciation and solubility of neptunium were studied using paper electrophoresis, ion exchange and ultrafiltration. Among these methods, the paper electrophoresis was found to be suitable for measuring speciation and solubility of neptunium of low concentration, if chemical species had opposite charge to each other or dissolved species had a charge. Using paper electrophoresis, hydrolysis constants of NpO 2 OH 0 and NpO 2 - (OH) 2 - and solubility product of NpO 2 were obtained and ionic-strength dependence of speciation was observed. (author) 9 refs.; 3 figs.; 2 tabs

  16. Characterization of Neptunium Oxide Generated Using the HB-Line Phase II Flowsheet

    Energy Technology Data Exchange (ETDEWEB)

    Duffey, J

    2003-08-29

    Approximately 98 grams of neptunium(IV) oxide (NpO{sub 2}) were produced at the Savannah River Technology Center (SRTC) for use in gas generation tests to support the neptunium stabilization program at the Savannah River Site (SRS). The NpO{sub 2} was produced according to the anticipated HB-Line flowsheet consisting of anion exchange, oxalate precipitation, filtration, and calcination. Characterization of the NpO{sub 2} product to be used in gas generation tests included bulk and tap density measurements, X-ray diffraction, particle size distribution, specific surface area measurements, and moisture analysis.

  17. Unusual radiolytic behavior of neptunium ions in aqueous bicarbonate solutions

    International Nuclear Information System (INIS)

    Shilov, V.P.; Gogolev, A.V.; Pikaev, A.K.

    2000-01-01

    Behavior of neptunium ions in carbonate and bicarbonate aqueous solutions saturated with air, oxygen or argon during gamma radiation ( 60 Co) by doses up to 3 kGy at dose rates 10 and 25 Gy/min was studied by the method of spectrophotometry. It is shown that in neptunium (5) bicarbonate solution nearly complete (95%) neptunium ion oxidation occurs under the effect of radiation, whereas no oxidation is observed in carbonate solution. Radiation-chemical yield of neptunium (5) oxidation and stationary concentration of neptunium (6) ions depend on concentration of bicarbonate-ions. Explanation to the results obtained is made from the viewpoint of potential radiolytic reactions [ru

  18. The use of neptunium-239 to assess neptunium distribution throughout a nuclear fuel reprocessing plant

    International Nuclear Information System (INIS)

    Mair, M.A.; Savage, D.J.; Prentice, P.C.

    1989-08-01

    A radiometric technique has been devised to use the gamma emission from the neptunium-239 daughter of americium-243 to estimate neptunium distribution in a plant reprocessing irradiated plutonium based fuels. Three trials were undertaken with samples from the Prototype Fast Reactor at Dounreay. The trials have confirmed the previous chemical measurements and the usefulness of this technique to highlight the effect of altered flowsheet conditions. (author)

  19. Process chemistry of neptunium. Part II

    Energy Technology Data Exchange (ETDEWEB)

    Srinivasan, N.; Ramaniah, M. V.; Patil, S. K.; Ramakrishna, V. V.; Swarup, R.; Chadha, A.; Avadhany, G. V.N.

    1974-07-01

    The oxidation state analysis of neptunium in the aqueous feed solution from the Plutonium Plant at Trombay was carried out and it was found that neptunium existed mainly as Np(V) in the feed solution. Batch extraction data for Np(IV) and Np(VI) into 30% TBP/Shell Sol T at different aqueous nitric acid concentration and uranium saturation of the organic phase were obtained at 45 deg C and 60 deg C and the results are summarized. The distribution coefficients of Np(IV) and Np(VI) were obtained as a function of TBP concentration and the data are reported. The effect of nitrous acid on the extraction of neptunium, present in the aqueous phase as Np(IV) and Np(V), by 30% TBP was studied and the data obtained are given. The data on the rate of reduction of NP(VI) and Np(V) to Np(IV) by U(IV) were obtained for different U(IV) and nitric acid concentrations. Some redox reactions involving Np(IV), Pu(IV) and V(V) were investigated and their possible application in the purex process for neptunium recovery were explored. (auth)

  20. Sorption of neptunium under oxidizing and reducing groundwater conditions

    International Nuclear Information System (INIS)

    Hakanen, M.

    1991-01-01

    Sorption of neptunium was studied under aerobic, anoxic and reducing groundwater conditions using solutions with initial Np concentrations of 10 -14 to 10 -8 mol/l. Under aerobic conditions the sorption was the same for all concentrations. Under anoxic conditions the same proportion of neptunium (70-80%) was removed from the water. The neptunium sorbed on rock surfaces was of mixed oxidation states. Only Np(V) was found in waters. Under reducing groundwater conditions, nearly all the neptunium was removed from water. The sorbed neptunium was at first almost completely in the form of Np(IV). The submicrogram amounts of neptunium were partly oxidized with time, but Np(V) did not dissolve in reducing water. The holding oxidant character of the tonalite to Np(V) and, the holding reductant character of rocks to small amounts of Np(IV), was demonstrated under anaerobic and reducing groundwater conditions, respectively. (orig.)

  1. Study of neptunium hexafluoride formation and its adsorption on metallic fluorides

    International Nuclear Information System (INIS)

    Matcheret, Georges

    1970-01-01

    This report involves two parts. The first part deals with the action of elementary fluorine on neptunium compounds by a thermogravimetric method. The mechanism and the kinetics of this reaction vary according to the nature of the compound. 1 - With neptunium tetrafluoride the reaction, proceeds in a single step. The kinetics corresponds to a uniform attack of the entire surface of the sample and follows the kinetics law: (1-α) 1/3 1-k rel t . 2 - The reaction with neptunium dioxyde involves two steps, neptunium tetrafluoride being the intermediate compound. The kinetics of the first step corresponds to a diffusion process and follows the kinetic law: log (1-α) = kt 1/2 . The kinetics of the second step corresponds to an uniform attack of the entire sur face of the sample. The object of the second part is a study of the adsorption of uranium hexafluoride and neptunium hexafluoride on sodium, magnesium and barium fluorides by a volumetric method. The adsorption of UF 6 on MgF 2 has been investigated at 20 deg. C. The isothermal curve obtained is characteristic of a physical one layer monomolecular adsorption. In a way similar to the behaviour of UF 6 the adsorption of NpF 6 involves in addition a chemical reduction with formation of NpF 5 and release of fluorine. The reaction of NpF 6 with BaF 2 permitted to confirm the influence of the polarizing power of the Ba ++ ion on formation and stability of the product of addition. (author) [fr

  2. Comparison of neptunium sorption results using batch and column techniques

    International Nuclear Information System (INIS)

    Triay, I.R.; Furlano, A.C.; Weaver, S.C.; Chipera, S.J.; Bish, D.L.

    1996-08-01

    We used crushed-rock columns to study the sorption retardation of neptunium by zeolitic, devitrified, and vitric tuffs typical of those at the site of the potential high-level nuclear waste repository at Yucca Mountain, Nevada. We used two sodium bicarbonate waters (groundwater from Well J-13 at the site and water prepared to simulate groundwater from Well UE-25p No. 1) under oxidizing conditions. It was found that values of the sorption distribution coefficient, Kd, obtained from these column experiments under flowing conditions, regardless of the water or the water velocity used, agreed well with those obtained earlier from batch sorption experiments under static conditions. The batch sorption distribution coefficient can be used to predict the arrival time for neptunium eluted through the columns. On the other hand, the elution curves showed dispersivity, which implies that neptunium sorption in these tuffs may be nonlinear, irreversible, or noninstantaneous. As a result, use of a batch sorption distribution coefficient to calculate neptunium transport through Yucca Mountain tuffs would yield conservative values for neptunium release from the site. We also noted that neptunium (present as the anionic neptunyl carbonate complex) never eluted prior to tritiated water, which implies that charge exclusion does not appear to exclude neptunium from the tuff pores. The column experiments corroborated the trends observed in batch sorption experiments: neptunium sorption onto devitrified and vitric tuffs is minimal and sorption onto zeolitic tuffs decreases as the amount of sodium and bicarbonate/carbonate in the water increases

  3. Fundamental studies of uranium and neptunium redox flow batteries (II)

    International Nuclear Information System (INIS)

    Shiokawa, Y.; Yamamura, T.; Watanabe, N.

    2002-01-01

    The atomic power generation entails production of so-called minor actinides and accumulation of depleted uranium. The theoretical and experimental investigations are underway to transmute minor actinides for minimizing the long-term radiotoxicity and reducing the radioactive waste. The utilization, however, would be alternative means. The actinide redox couples, An(VI)/An(V) and An(IV)/An(III), have excellent properties as battery active materials. Here j the uranium and neptunium redox flow batteries for the electric power storage are discussed from the electrochemical properties of U, Np, Pu and Am [1,2]. One of the required properties for the batteries for electric power storage is high energy efficiency, which is defined by the ratio of the discharge energy to the charge energy. These energies are dependent on the rapidness of kinetics in the electrode reactions, namely the standard rate constants and also the internal resistance of the battery

  4. Neptunium speciation (complexation and redox behaviour) in aqueous citrate medium

    International Nuclear Information System (INIS)

    Bonin, L.; Ansoborlo, E.; Moisy, Ph.

    2005-01-01

    Full text of publication follows: In the framework of the French Environmental Nuclear Toxicology programme, additional experiments related to the decorporation of actinides are planned. The lack of information on the neptunium behaviour within blood and the inefficiency of therapeutic treatments, led us to study the complexation of this element with basic anions. Within this purpose, the in vitro behaviour of Np IV and Np V in simple media simulating biological media was studied: blood plasma is one of the media of interest and it can be simulated, from a chemical point of view, by an aqueous solution with pH 7.4, containing ions such as citrate (1.6 10 -4 mol/L), lactate (1.5 10 -3 mol/L), CO 3 2- (2.5 10 -2 mol/L), PO 4 3- (1.1 10 -3 mol/L), SO 4 2- (3.3 10 -4 mol/L) and Cl - (9 10 -2 mol/L). This study was more specifically focused on the behaviour of neptunium with citrate ion, which is also a basic ligand to consider when one wishes to study the migration of actinides in the environment, since it exists in significant amounts in the ground due to its production by the plants. In order to determine the speciation of this system, spectrophotometry was more particularly used. Concerning the complexation phenomenon, the existence of several complexes of Np V with various acid-basic forms of the citrate anion was observed; regarding Np IV , two complexes, with 1:1 and 1:2 stoichiometry, have been respectively observed. The reactivity of Np VI is probably similar to the behaviour of U VI , which is reported in literature to form a complex with a 1:1 stoichiometry with the Cit 3- anion From the quantitative study of these equilibria, it has been possible to determine the values of various equilibrium constants. Concerning the stability of neptunium towards oxido-reduction, it was confirmed that Np VI was very quickly reduced to Np V by the citrate anions, whereas Np IV was stable. In the case of Np V , it was observed that, depending on the pH and the citrate

  5. Determination of neptunium by redox titration

    International Nuclear Information System (INIS)

    Godbole, A.G.; Patil, S.K.

    1979-01-01

    A simple and quick method for the potentiometric determination of neptunium on the 2 to 5 mg scale has been developed. It consists of oxidation to Np(VI) by AgO or fuming with HClO 4 , destruction of excess of AgO by sulphamic acid, reduction of Np(VI) to Np(IV) with a slight excess of standard Fe(II) in 2M H 2 SO 4 and potentiometric titration of the excess of Fe(II) with standard Ce(IV). The precision is +- 0.5%. (author)

  6. Transport of neptunium through Yucca Mountain tuffs

    International Nuclear Information System (INIS)

    Triay, I.R.; Robinson, B.A.; Mitchell, A.J.; Overly, C.M.; Lopez, R.M.

    1993-01-01

    Neptunium has a high solubility in groundwaters from Yucca Mountain [1]. Uranium in nuclear reactors produces 237 Np which has a half-life of 2.1 4 x 10 6 years. Consequently, the transport of 237 Np through tuffs is of major importance in assessing the performance of a high-level nuclear waste repository at Yucca Mountain. The objective of this work is to determine the amount of Np retardation that is provided by the minerals in Yucca Mountain tuffs as a function of groundwater chemistry

  7. Redox reactions of neptunium in tributyl phosphate-dodecane mixtures

    International Nuclear Information System (INIS)

    Wehrey, F.

    1989-01-01

    In relation with the reprocessing of irradiated fuels, disproportionation and oxidation by nitric acid of pentavalent neptunium in tributyl phosphate-dodecane mixtures have been studied. The experimental part of this work is based on spectrophotometric measurements. The disproportionation of pentavalent neptunium in organic perchloric medium is a second order reaction with respect to neptunium V. The reaction rate is strongly influenced by the perchloric acid concentration and has a higher value than in an aqueous medium. The reverse reaction in nitric media is a first order with respect to tetravalent and hexavalent ions. The reaction rate is a function of the reverse of the square of the nitric acid concentration. The energy of activation is the same than in aqueous medium. The oxidation rate of pentavalent neptunium by nitric acid is increased by nitrous acid. When no nitrous acid is added to the mixture, the reaction revealed to be autocatalytic, possesses an induction period. When nitrous and nitric acids are in excess to neptunium the reaction is first order with respect to neptunium. The reaction rate depends on the concentration of nitric acid and is a linear function of the concentration of nitrous acid. In tributyl phosphate dodecane mixtures the reaction occurs spontaneously. It is not the case in aqueous media. The values of thermodynamical and kinetical constants determined in this work could be used in a modelization of the behavior of neptunium in the reprocessing of irradiated fuels, which has to eliminate this element among its tasks [fr

  8. Precipitaion of neptunium(6) by urotropin from the heated solutions

    International Nuclear Information System (INIS)

    Logvis', A.I.; Krot, N.N.

    1992-01-01

    The composition of precipitate, formed in the course of neptunium(6) nitric acid solution heating with urotropin under different conditions was studied by the methods of X-ray phase analysis, gravimetry and spectrophotometry. The compound studied is determined as NpO 3 ·xH 2 O·yNH 3 , where x <= 2, y <= 0.28. It is shown that not less than 12 % of the initial amount of neptunium remain in solution in the form of neptunium(5)

  9. Neptunium 237 behaviour in subcellular fractions of rat kidneys

    International Nuclear Information System (INIS)

    Kreslov, V.V.; Maksutova, A.Ya.; Mushkacheva, G.S.

    1978-01-01

    Subcellular distribution of intravenously injected (1 and 0.5 μCi/rat) neptunium nitrate (5- and 6-valent) in kidneys of rat males and females has been investigated. It has been shown that the radionuclide was unevenly distributed within the cell. As early as 24 hours after administration, about 50 per cent of neptunium were concentrated in the mitochondrial fraction. The data are presented on variations in neptunium behaviour within subcellular fractions of rat kidneys depending on the sex of animals, valency and dose of the isotope

  10. Neptunium immobilization and recovery using phase separated glasses

    International Nuclear Information System (INIS)

    Meaker, T.F.

    1997-01-01

    A phase separated (amorphous) glass has been developed which allows very efficient recovery of +4 valence actinides. The total amount of crystal formation in a heat treated vycor-type glass can be controlled with time, temperature and loading. Heat treatments at lower temperatures and for less time inhibit crystal formation while still allowing significant phase separation. If the Thorium loading exceeds 10 weight percent oxide, crystal formation during heat treatment may not be avoided. The total amount of crystal growth has a direct affect on thorium leachability. An increase in crystal formation limits the Th recovery significantly. High thorium loaded glasses (15 weight percent) with heat treatments (increased crystal formation) leach at approximately the same rate as non-heat treated glasses. A phase separated (amorphous) glass has been produced using thorium as a surrogate for neptunium. Two different homogeneous vycor compositions targeting 10 and 15 weight percent thorium oxide have been processed, heat treated and leached with concentrated nitric acid at 110 degrees C. Thorium recovery rates have been shown to be considerably better when the glass has been heat treated inducing phase separation that is relatively crystal free. Non-heat treated and crystalline (due to heat treatment) glasses have similar Th recovery rates with respect to surface area. Phase separated amorphous samples were found to have significantly higher thorium concentrations in the leachate compared to non-heat treated and crystalline glasses for all mesh sizes. All glasses had increased thorium concentration in the leachate as surface area increased

  11. Surface Complexation of Neptunium(V) with Goethite

    International Nuclear Information System (INIS)

    Jerden, James L.; Kropf, A. Jeremy

    2007-01-01

    Batch adsorption experiments in which neptunium-bearing solutions were reacted with goethite (alpha-FeOOH) have been performed to study uptake mechanisms in sodium chloride and calcium-bearing sodium silicate solutions. This paper presents results identifying and quantifying the mechanisms by which neptunium is adsorbed as a function of pH and reaction time (aging). Also presented are results from tests in which neptunium is reacted with goethite in the presence of other cations (uranyl and calcium) that may compete with neptunium for sorption sites. The desorption of neptunium from goethite has been studied by re-suspending the neptunium-loaded goethite samples in solutions containing no neptunium. Selected reacted sorbent samples were analyzed by x-ray absorption spectroscopy (XAS) to determine the oxidation state and molecular speciation of the adsorbed neptunium. Results have been used to establish the pH adsorption edge of neptunium on goethite in sodium chloride and calcium-bearing sodium silicate solutions. The results indicate that neptunium uptake on goethite reaches 95% at a pH of approximately 7 and begins to decrease at pH values greater than 8.5. Distribution coefficients for neptunium sorption range from less than 1000 (moles/kg) sorbed / (moles/kg) solution at pH less than 5.0 to greater than 10,000 (moles/kg) sorbed / (moles/kg) solution at pH greater than 7.0. Distribution coefficients as high as 100,000 (moles/kg) sorbed / (moles/kg) solution were recorded for the tests done in calcite equilibrated sodium silicate solutions. XAS results show that neptunium complexes with the goethite surface mainly as Np(V) (although Np(IV) is prevalent in some of the longer-duration sorption tests). The neptunium adsorbed to goethite shows Np-O bond length of approximately 1.8 angstroms which is representative of the Np-O axial bond in the neptunyl(V) complex. This neptunyl(V) ion is coordinated to 5 or 6 equatorial oxygens with Np-O bond lengths of 2

  12. Sorption of americium and neptunium by deep-sea sediments

    International Nuclear Information System (INIS)

    Higgo, J.J.W.; Rees, L.V.C.; Cronan, D.S.

    1983-01-01

    The sorption and desorption of americium and neptunium by a wide range of deep-sea sediments from natural sea water at 4 0 C has been studied using a carefully controlled batch technique. All the sediments studied should form an excellent barrier to the migration of americium since distribution coefficients were uniformly greater than 10 5 and the sorption-desorption reaction may not be reversible. The sorption of neptunium was reversible and, except for one red clay, the distribution coefficients were greater than 10 3 for all the sediments investigated. Nevertheless the migration of neptunium should also be effectively retarded by most deep-sea sediments even under relatively oxidizing conditions. The neptunium in solution remained in the V oxidation state throughout the experiments. Under the experimental conditions used colloidal americium was trapped by the sediment and solubility did not seem to be the controlling factor in the desorption of americium. (Auth.)

  13. Two-stage precipitation of neptunium (IV) oxalate

    International Nuclear Information System (INIS)

    Luerkens, D.W.

    1983-07-01

    Neptunium (IV) oxalate was precipitated using a two-stage precipitation system. A series of precipitation experiments was used to identify the significant process variables affecting precipitate characteristics. Process variables tested were input concentrations, solubility conditions in the first stage precipitator, precipitation temperatures, and residence time in the first stage precipitator. A procedure has been demonstrated that produces neptunium (IV) oxalate particles that filter well and readily calcine to the oxide

  14. Hydrolysis constants of tetravalent neptunium by using solvent extraction method

    International Nuclear Information System (INIS)

    Fujiwara, K.; Kohara, Y.

    2008-01-01

    The hydrolysis constants of tetravalent neptunium (Np(IV)) were determined by solvent extraction method using thenoyltrifluoroacetone(TTA). In order to avoid colloid formation, a stock solution of carrier-free 239 Np(V) was from 243 Am milked. The valence of Np in the solution was then reduced to Np(IV) by using zinc amalgam. The hydrolysis constants (β m ) of the reactions, Np 4+ + mOH - = Np(OH) m (4-m)+ was evaluated by using distribution ratios at ionic strengths (I) = 0.1, 0.5 and 1.0. All experiments were performed in oxygen-free 0.5% H 2 -N 2 atmosphere (below 1.0 ppm of O 2 ) in a glove-box at room temperature (23 ± 2 C) to avoid oxidation of Np(IV). The β m values were extrapolated to the standard state (I = 0) by using the specific ion interaction theory (SIT), and the formation constants at I = 0 were determined to be log β 1 = 13.91 ± 0.23, log β 2 = 27.13 ± 0.15, log β 3 = 37.70 ± 0.30 and log β 4 = 46.16 ± 0.30. The ion interaction coefficients were also evaluated to be ε(NpOH 3+ , ClO 4 - ) = 0.49 ± 0.15, ε(Np(OH) 2 2+ , ClO 4 - ) = 0.35 ± 0.11, and ε(Np(OH) 3 + , ClO 4 - ) = 0.29 ± 0.15. (orig.)

  15. Hydrolysis constants of tetravalent neptunium by using solvent extraction method

    Energy Technology Data Exchange (ETDEWEB)

    Fujiwara, K. [Japan Atomic Energy Agency (JAEA), Naka-gun, Ibaraki-ken (Japan); Kohara, Y. [Inspection and Development Co., Naka-gun, Ibaraki-ken (Japan)

    2008-07-01

    The hydrolysis constants of tetravalent neptunium (Np(IV)) were determined by solvent extraction method using thenoyltrifluoroacetone(TTA). In order to avoid colloid formation, a stock solution of carrier-free {sup 239}Np(V) was from {sup 243}Am milked. The valence of Np in the solution was then reduced to Np(IV) by using zinc amalgam. The hydrolysis constants ({beta}{sub m}) of the reactions, Np{sup 4+} + mOH{sup -} = Np(OH){sub m}{sup (4-m)+} was evaluated by using distribution ratios at ionic strengths (I) = 0.1, 0.5 and 1.0. All experiments were performed in oxygen-free 0.5% H{sub 2}-N{sub 2} atmosphere (below 1.0 ppm of O{sub 2}) in a glove-box at room temperature (23 {+-} 2 C) to avoid oxidation of Np(IV). The {beta}{sub m} values were extrapolated to the standard state (I = 0) by using the specific ion interaction theory (SIT), and the formation constants at I = 0 were determined to be log {beta}{sub 1} = 13.91 {+-} 0.23, log {beta}{sub 2} = 27.13 {+-} 0.15, log {beta}{sub 3} = 37.70 {+-} 0.30 and log {beta}{sub 4} = 46.16 {+-} 0.30. The ion interaction coefficients were also evaluated to be {epsilon}(NpOH{sup 3+}, ClO{sub 4}{sup -}) = 0.49 {+-} 0.15, {epsilon}(Np(OH){sub 2}{sup 2+}, ClO{sub 4}{sup -}) = 0.35 {+-} 0.11, and {epsilon}(Np(OH){sub 3}{sup +}, ClO{sub 4}{sup -}) = 0.29 {+-} 0.15. (orig.)

  16. Neptunium speciation (complexation and redox behaviour) in aqueous citrate medium

    Energy Technology Data Exchange (ETDEWEB)

    Bonin, L.; Ansoborlo, E.; Moisy, Ph. [CEA Marcoule (France)

    2005-07-01

    Full text of publication follows: In the framework of the French Environmental Nuclear Toxicology programme, additional experiments related to the decorporation of actinides are planned. The lack of information on the neptunium behaviour within blood and the inefficiency of therapeutic treatments, led us to study the complexation of this element with basic anions. Within this purpose, the in vitro behaviour of Np{sup IV} and Np{sup V} in simple media simulating biological media was studied: blood plasma is one of the media of interest and it can be simulated, from a chemical point of view, by an aqueous solution with pH 7.4, containing ions such as citrate (1.6 10{sup -4} mol/L), lactate (1.5 10{sup -3} mol/L), CO{sub 3}{sup 2-} (2.5 10{sup -2} mol/L), PO{sub 4}{sup 3-} (1.1 10{sup -3} mol/L), SO{sub 4}{sup 2-} (3.3 10{sup -4} mol/L) and Cl{sup -} (9 10{sup -2} mol/L). This study was more specifically focused on the behaviour of neptunium with citrate ion, which is also a basic ligand to consider when one wishes to study the migration of actinides in the environment, since it exists in significant amounts in the ground due to its production by the plants. In order to determine the speciation of this system, spectrophotometry was more particularly used. Concerning the complexation phenomenon, the existence of several complexes of Np{sup V} with various acid-basic forms of the citrate anion was observed; regarding Np{sup IV}, two complexes, with 1:1 and 1:2 stoichiometry, have been respectively observed. The reactivity of Np{sup VI} is probably similar to the behaviour of U{sup VI}, which is reported in literature to form a complex with a 1:1 stoichiometry with the Cit{sup 3-}anion From the quantitative study of these equilibria, it has been possible to determine the values of various equilibrium constants. Concerning the stability of neptunium towards oxido-reduction, it was confirmed that Np{sup VI} was very quickly reduced to Np{sup V} by the citrate anions

  17. The effect of carbonate on neptunium sorption by hydroxyapatite

    International Nuclear Information System (INIS)

    Moore, R.C.; Holt, K.

    2005-01-01

    Full text of publication follows: Hydroxyapatite, Ca 10 (PO 4 ) 6 (OH) 2 , is a common mineral, the main inorganic compound in bone and exhibits strong sorptive properties for many radionuclides. It has been widely studied and proposed as a backfill material for nuclear waste repositories. Neptunium is one the radionuclides sorbed by hydroxyapatite. Neptunium is of particular importance to nuclear waste repository performance because of its relatively high aqueous solubility, high mobility in the environment and long half-life. In this work, we report on the effects of carbonate on sorption of neptunium by hydroxyapatite. Batch sorption and desorption studies for neptunium were performed as a function of carbonate concentration in water using a synthetic hydroxyapatite. The results indicate even low concentrations of carbonate significantly reduce neptunium sorption and enhance desorption. The data were fit to several simple isotherm equations with the Langmuir equation giving the best results. The results of the work are discussed with respect to nuclear waste repository performance. (authors)

  18. Fate of neptunium in an anaerobic, methanogenic microcosm

    International Nuclear Information System (INIS)

    Banaszak, J.E.; Webb, S.M.; Rittmann, B.E.; Gaillard, J.F.; Reed, D.T.

    1999-01-01

    Neptunium is found predominantly as Np(IV) in reducing environments, but as Np(V) in aerobic environments. Currently, it is not known how the interplay between biotic and abiotic processes affects Np redox speciation in the environment. To evaluate the effect of anaerobic microbial activity on the fate of Np in natural systems, Np(V) was added to a microcosm inoculated with anaerobic sediments from a metal-contaminated freshwater lake. The consortium included metal-reducing, sulfate-reducing, and methanogenic microorganisms, and acetate was supplied as the only exogenous substrate. Addition of more than 10 -5 M Np did not inhibit methane production. Total Np solubility in the active microcosm, as well as in sterilized control samples, decreased by nearly two orders of magnitude. A combination of analytical techniques, including VIS-NIR absorption spectroscopy and XANES, identified Np(IV) as the oxidation state associated with the sediments. The similar results from the active microcosm and the abiotic controls suggest that microbially produced Mn(II/III) and Fe(II) may serve as electron donors for Np reduction

  19. An evaluation of safeguards approaches for neptunium

    International Nuclear Information System (INIS)

    Burr, Tom; Stanbro, William D.; Charlton, William

    2001-01-01

    The International Atomic Energy Agency has recently drawn attention to the fact that neptunium (Np), a byproduct of the nuclear power industry, can be used to make nuclear weapons. Current monitoring approaches for Np do not rely on material balance accounting as is used for uranium and plutonium. In the future this may change. Although full material balance accounting is not anticipated for Np, it is informative to evaluate the impact and benefit of full material balance accounting when considering other options. Therefore, this paper will apply systems analysis to evaluate ways to convert the current system to full materials balance accounting that will minimize the intrusiveness of the verification system and minimize costs to both the facility operator and the inspection agency. We then compare full material balance accounting to partial material balance accounting and to a ratio-monitoring technique referred to as flow sheet verification. We conclude that sampling approximately 25% of the batches is likely to be adequate and that Pu (or perhaps 137 Cs) will be the most effective surrogate for estimating the Np in the input accountability tank. (author)

  20. Effect of natural organic materials on cadmium and neptunium sorption

    International Nuclear Information System (INIS)

    Kung, K.S.; Triay, I.R.

    1994-01-01

    In a batch sorption study of the effect of naturally occurring organic materials on the sorption of cadmium and neptunium on oxides and tuff surfaces, the model sorbents were synthetic goethite, boehmite, amorphous silicon oxides, and a crushed tuff material from Yucca Mountain, Nevada. An amino acid, 3-(3,4-dihydroxypheny)-DL-alanine (DOPA), and an aquatic-originated fulvic material, Nordic aquatic fulvic acid (NAFA), were used as model organic chemicals. Sorption isotherm results showed that DOPA sorption followed the order aluminum oxide > iron oxide > silicon oxide and that the amount of DOAP sorption for a given sorbent increased as the solution pH was raised. The sorption of cadmium and neptunium on the iron oxide was about ten times higher than that on the aluminum oxide. The sorption of cadmium and neptunium on natural tuff material was much lower than that on aluminum and iron oxides. The sorption of cadmium on iron and aluminum oxides was found to be influenced by the presence of DOPA, and increasing the amount of DOPA coating resulted in higher cadmium sorption on aluminum oxide. However, for iron oxide, cadmium sorption decreased with increasing DOPA concentration. The presence of the model organic materials DOPA and NAFA did not affect the sorption of neptunium on tuff material or on the iron and aluminum oxides. Spectroscopic results indicate that cadmium complexes strongly with DOPA. Therefore, the effect of the organic material, DOPA, on the cadmium sorption is readily observed. However, neptunium is possibly complexed weakly with organic material. Thus, DOPA and NAFA have little effect on neptunium sorption on all sorbents selected for study

  1. Radiation-chemical behaviour of neptunium ions in nitric acid solutions in the presence of curium-244

    International Nuclear Information System (INIS)

    Frolova, L.M.; Frolov, A.A.; Vasil'ev, V.Ya.

    1984-01-01

    Radiation-chemical behaviour of neptunium ions in nitric acid solutions is studied under the action of intensive internal alpha-irradiation conditioned by curium nuclides. In 0.3-1.1 mol/l solutions of nitric acid radiation-chemical oxidation of neptunium (4) and reduction of neptunium (6) is obeyed to the first order law of reaction rate in respect to neptunium concentration. Effective constants of neptunium (4) oxidation rates and neptuniumi(6) reduction rates are not dependent on neptunium ion in1tial concentration and increase with a growth of a dose rate of alpha-irradiation of solution. In equilibrium only neptunium (5) and neptunium (6) are present in solutions with HNO 3 concentration less than 1 mol/l. In more concentrated solutions equilibrium between sexa-, penta- and tetravalent neptunium forms is established. Equilibrium concentrations of neptunium valent forms are not dependent on neptunium initial oxidation state under the same initial conditions (dose rate, neptunium concentration and acidity. It is shown form experimental data that under the action of alpha-irradiation neptunium (5) both is oxidated to neptunium (6) and is reduced to neptunium (4)

  2. Increased sugarcane water productivity in Brazil avoids land use change and related environmental impacts

    Science.gov (United States)

    Scarpare, F. V.; Galdos, M. V.; Kolln, O.; Gava, G.; Franco, H.; Trivelin, P.

    2012-12-01

    ratoon cane cycle. In order to demonstrate the potential effect of avoided land use change by increased productivity, we calculated the avoided GHG emissions related to land use change in a hypothetical fertirrigation project over a ten-year period (2010-2020). A conservative scenario for increased demand for sugarcane was selected, assuming a 20% increase in total production over the ten-year period. The current area under sugarcane in the municipality of Jaú is 42,500 ha. A 5,000 ha fertirrigation project, assuming the 40% increase in sugarcane productivity described above for the IN treatment, would avoid the conversion of 2,000 ha of other land uses in to sugarcane. Landsat data covering the region in the 2008/2009 crop year demonstrated that most conversion occurred over pasture areas (91%), with the remaining being converted from annual crops. Using IPCC biomass and soil carbon stock change factors and emission factors, the LUC-related emissions avoided by the fertirrigation project in the period were calculated as 53,199 Mg CO2 eq. A more comprehensive life cycle assessment of both the fertirrigation system and the reference case would be necessary to evaluate the actual GHG mitigation potential, but the preliminary results indicate that the increased productivity will bring environmental benefits under these conditions.

  3. Separation of different valency states of neptunium from processing solutions

    International Nuclear Information System (INIS)

    Shabana, R.; EL-Naggar, H.A.

    1990-01-01

    The three main oxidation states of neptunium (Np(IV),Np(V) and Np(V I)) have been separated from each other by solvent extraction and extraction chromatographic techniques. The separation procedure is based on a systematic study of the extraction behaviour of each oxidation state using TBP as an extractant. The purity of separated species is identified using spectrophotometry

  4. Adsorption of neptunium and plutonium on metal phosphites

    International Nuclear Information System (INIS)

    Silver, G.L.

    1979-01-01

    The removal of neptunium and plutonium from water by adsorption on titanium, zirconium, bismuth, thorium, and uranium phosphites was investigated. These phosphites hydrolyze in neutral or alkaline solution producing the hydrous metal oxides that are more effective adsorbents than the original phosphite compounds. Ageing the plutonium-238 polymer changes its adsorption characteristics on commercial bone char. 37 figures, 7 tables

  5. Determination of neptunium in soil by ICP-MS

    International Nuclear Information System (INIS)

    Ayranov, M.; Kraehenbuehl, U.

    2005-01-01

    A fast and simple method for the determination of 237 Np in soil is presented. The borate fusion decreases the sample pre-treatment time and a TEVA extraction chromatography separates neptunium from uranium and the interfering matrix components. A comparison of the sensitivities of alpha spectrometry and sector field ICP-MS for determination of 237 Np is presented. (orig.)

  6. Interaction of neptunium with humic acid and anaerobic bacteria

    International Nuclear Information System (INIS)

    Kubota, Takumi; Sasaki, Takayuki; Kudo, Akira

    2002-01-01

    Humic acid and bacteria play an important role in the migration of radionuclides in groundwaters. The interaction of neptunium with humic acid and anaerobic bacteria has been investigated by liquid/liquid and solid/liquid extraction systems. For liquid/liquid extraction, the apparent complex formation constant, β α was obtained from the distribution between two phases of neptunium. For solid/liquid extraction, the ratio of sorption to bacteria, K d , was measured. K d of humic acid can be evaluated from β α . The large value of β α and K d means strong interaction of neptunium with organisms. In order to examine the effect of the nature of organism on interaction, the interaction with humic acid was compared to that with non-sterilized or sterilized mixed anaerobic bacteria. The value of β α of humate depended on neptunium ion concentration as well as pH, which showed the effect of polyelectrolyte properties and heterogeneous composition of humic acid. The comparison of interaction with humic acid and bacteria indicated that the K d value of humic acid was larger than that of bacteria and more strongly depend on pH. (author)

  7. Avoidance of cellular blood product transfusions in LVAD recipients does not prevent HLA allosensitization.

    Science.gov (United States)

    Stringham, J C; Bull, D A; Fuller, T C; Kfoury, A G; Taylor, D O; Renlund, D G; Karwande, S V

    1999-02-01

    Transfusion of cellular blood products during left ventricular assist device (LVAD) implantation has been associated with HLA allosensitization, resulting in the need for a negative prospective cross-match and prolonged transplant waiting times. In order to prevent this risk, we developed a protocol to avoid transfusion of cellular blood products. The protocol included preoperative patient stabilization, perioperative recombinant erythropoietin and blood conservation strategies, and postoperative monitoring of mixed venous oxygen saturation (SVO2) to assure adequate peripheral oxygen delivery. Panel reactive antibody (PRA) was measured in all patients pre and post LVAD placement to assess HLA sensitization. Seven consecutive patients underwent LVAD implantation without transfusion of blood or platelets, one of whom expired perioperatively. Mean hematocrit was 35.2% preoperatively, and 21.8% postoperatively, reaching a nadir of 20.2%. Postoperative SVO2 was >60% in all patients. In the six survivors, mean hematocrit reach 24.3%, 27.3%, and 33.0% by postoperative day seven, fourteen, and thirty, respectively. PRA in three patients was 0% preoperatively and remained 0% until transplantation after 33, 34, and 50 days of support. In two patients, preoperative PRA was 7% and 17%, dropped to 3% and 0% after thirty days, then progressively rose to 96% and 100% after 60 and 90 days, respectively. In one other patient, preoperative PRA was 0%, remained at 0% after thirty days, then rose to 96% by 60 days. Avoiding transfusion of cellular blood products in LVAD recipients is safe and well tolerated, but does not universally protect from HLA allosensitization. Other factors may also produce sensitization, such as immunogenic components of the LVAD, soluble antigen in fresh frozen plasma, or latent sensitization which is not initially evident in critically ill and possibly anergic patients.

  8. Neptunium(V) sorption on kaolinite

    Energy Technology Data Exchange (ETDEWEB)

    Amayri, S.; Jermolajev, A.; Reich, T. [Mainz Univ. (Germany). Inst. of Nuclear Chemistry

    2011-07-01

    The sorption behavior of neptunium(V) onto the clay mineral kaolinite was studied in batch experiments under different experimental conditions: [Np(V)] = 7 x 10{sup -12}-8 x 10{sup -6} M, solid-to-liquid ratio 2-20 g L{sup -1}, I = 0.1 and 0.01 M NaClO{sub 4}, pH = 6-10, ambient air and Ar atmosphere. The short-lived isotope {sup 239}Np (T{sub 1/2} = 2.36 d) was used instead of {sup 237}Np (T{sub 1/2} = 2.14 x 10{sup 6} a) to study the sorption behavior of Np(V) at environmentally-relevant concentrations, i.e., 7 x 10{sup -12} M Np. In addition, {sup 239}Np(V) served as tracer to measure sorption isotherms over six orders of magnitude in Np concentration (4.8 x 10{sup -12}-1.0 x 10{sup -4} M). The results show that Np(V) sorption on kaolinite is strongly influenced by pH, CO{sub 2}, and ionic strength. The sorption of 8 x 10{sup -6} M Np(V) at pH 9.0, and ionic strength of 0.1 M NaClO{sub 4} was proportional to the solid-to-liquid ratio of kaolinite in the range of 2-10 g L{sup -1}. In the absence of CO{sub 2}, the Np(V) uptake increased continuously with increasing pH value up to 97% at pH 10. Under ambient CO{sub 2}, the sorption of Np decreased above pH 8 up to zero at pH 10. An increase of Np(V) concentration from 7 x 10{sup -12} to 8 x 10{sup -6} M resulted in a shift of the sorption pH edge by up to one pH unit to higher pH values. The ionic strength influenced the Np(V) sorption onto kaolinite only in the presence of ambient CO{sub 2}. Under Ar atmosphere the sorption of Np(V) was independent from ionic strength, indicating the formation of inner-sphere complexes of Np(V) with kaolinite. Time-dependent batch experiments at pH 9.0 under ambient CO{sub 2} showed that the sorption of Np(V) on kaolinite is fast and fully reversible over six orders in Np(V) concentration. (orig.)

  9. Proper packaging for food and no-food products to avoid injuries.

    Science.gov (United States)

    Passali, Desiderio; Gregori, Dario; Foltran, Francesca

    2012-05-14

    This paper aims to present data on proper packaging for food and no-food products to avoid injuries. Data collection was made from the Susy Safe data base and the results of the literature research. Fatal and near fatal foreign bodies injuries may occur at any age, however it is a particular problem for infants and young children due to a variety of predisposing factors. Safety packaging is therefore a landmark and a model for accident prevention. Taken the lack of researches and specificity on this subject, it is warmly suggested that a broader and deeper exploration, both at customer's and public health levels, has to be made, highlighting major risks and complications. Packaging classes are extremely composite, therefore accuracy in data registry must be achieved, since from a preventive point of view it is basilar not only knowing the nature of the foreign body but also having information on its origin. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  10. Corrosion of type 304L stainless steel in boiling dilute neptunium nitrate solution

    International Nuclear Information System (INIS)

    Motooka, Takafumi; Kiuchi, Kiyoshi

    2003-01-01

    Corrosion of type 304L stainless steel in nitric acid solution containing neptunium was studied under immersion and heat-transfer condition. Corrosion rates of stainless steel were obtained by the weight loss measurement and the quantitative analysis of metallic ions dissolved in solution. The surface morphology was observed by scanning electron microscopy. The corrosion acceleration mechanism was investigated by polarization measurement and spectrophotometry. The corrosion rate in boiling 9M nitric acid was accelerated by addition of neptunium. The corrosion of stainless steel was promoted under heat-transfer condition compared to immersion condition. In polarization measurements, the cathodic current was increased by addition of neptunium. Spectrophotometric measurements showed the oxidization of neptunium in boiling nitric acid. It was suggested that the accelerated corrosion in nitric acid solution containing neptunium was caused by re-oxidation of neptunium. (author)

  11. Sorption behavior of neptunium on bentonite -- Effect of calcium ion on the sorption

    International Nuclear Information System (INIS)

    Kozai, Naofumi; Ohnuki, Toshihiko; Muraoka, Susumu

    1995-01-01

    The sorption behavior of neptunium on bentonite was studied with batch type sorption and desorption experiments over a pH range of 2 to 8. A series of parallel studies using Na-smectite, Ca-smectite and admixtures of Na-smectite and calcite quantified the capacity of Ca 2+ (which occurs in bentonite as an exchangeable cation of smectite and as a component of calcite) to inhibit the sorption of neptunium. The distribution coefficient (K d ) of neptunium for bentonite was constant from pH 2 to 7, while for pure Na-smectite K d increased below pH 5 due to specific sorption of neptunium on Na-smectite. Specific sorption was defined as occurring when neptunium could be desorbed by a strong acid (1 M HCl) but was stable in the presence of 1 M KCl. It was found that the quantity of neptunium sorbed on Na-smectite was inversely proportional to the concentration of Ca 2+ in solution, an effect most pronounced at pH 2+ limits the specific sorption capacity of Na-smectite for neptunium. Similarly, in the mixture of Na-smectite and calcite, sufficient Ca 2+ was solubilized to depress neptunium sorption. This investigation demonstrates that Ca 2+ contained in bentonite as exchangeable cation and released from calcite reduces the specific sorption of neptunium

  12. Sugarcane ethanol production in Malawi: Measures to optimize the carbon footprint and to avoid indirect emissions

    International Nuclear Information System (INIS)

    Dunkelberg, Elisa; Finkbeiner, Matthias; Hirschl, Bernd

    2014-01-01

    Sugarcane ethanol is considered to be one of the most efficient first-generation biofuels in terms of greenhouse gas (GHG) emissions. The carbon footprint (CF), however, increases significantly when taking into account emissions induced by indirect land-use changes (ILUC). This case study investigates sugarcane ethanol production in the Republic of Malawi, in Sub-Sahara Africa (SSA); the research objectives were to identify and quantify direct and indirect emissions and to identify measures to optimize the CF. The CF has been calculated with a life cycle approach and with data obtained from the involved companies; our estimations with regard to ILUC take into account further expansion plans for sugarcane crop production. Under existing production conditions ethanol produced in Malawi leads to GHG emissions expressed as CO 2eq of 116 g MJ −1 of ethanol. However, high optimization potentials exist when the vinasse is used as an input for biogas production and the harvesting switches from pre-harvest burning to green harvesting. ILUC induced by prospective sugarcane expansions in the Southern Region will, according to current planning, probably not occur since these expansions are linked to the implementation of a large-scale irrigation project. However if ILUC takes place, high levels of additional CO 2 emissions of about 77 g MJ −1 of ethanol are to be expected. Although the case study results are only valid for a specific region, some of the findings, such as the high compensation potential regarding ILUC through investments in irrigation systems, may be transferable to other regions in SSA. - Highlights: • We conducted a case study on sugarcane ethanol production in Malawi and calculated its carbon footprint (CF). • The current CF of sugarcane ethanol produced in the Southern Region in Malawi amounts for 116 g MJ −1 of ethanol. • The usage of vinasse in biogas plants would significantly improve the CF. • Another optimization measure is to

  13. XAS and TRLIF spectroscopy of uranium and neptunium in seawater.

    Science.gov (United States)

    Maloubier, Melody; Solari, Pier Lorenzo; Moisy, Philippe; Monfort, Marguerite; Den Auwer, Christophe; Moulin, Christophe

    2015-03-28

    Seawater contains radionuclides at environmental levels; some are naturally present and others come from anthropogenic nuclear activity. In this report, the molecular speciation in seawater of uranium(VI) and neptunium(V) at a concentration of 5 × 10(-5) M has been investigated for the first time using a combination of two spectroscopic techniques: Time-resolved laser-induced fluorescence (TRLIF) for U and extended X-ray absorption fine structure (EXAFS) for U and Np at the LIII edge. In parallel, the theoretical speciation of uranium and neptunium in seawater at the same concentration is also discussed and compared to spectroscopic data. The uranium complex was identified as the neutral carbonato calcic complex UO2(CO3)3Ca2, which has been previously described in other natural systems. In the case of neptunium, the complex identified is mainly a carbonato complex whose exact stoichiometry is more difficult to assess. The knowledge of the actinide molecular speciation and reactivity in seawater is of fundamental interest in the particular case of uranium recovery and more generally regarding the actinide life cycle within the biosphere in the case of accidental release. This is the first report of actinide direct speciation in seawater medium that can complement inventory data.

  14. Re-evaluating neptunium in uranyl phases derived from corroded spent fuel

    International Nuclear Information System (INIS)

    Fortner, J. A.; Finch, R. J.; Kropf, A. J.; Cunnane, J. C.; Chemical Engineering

    2004-01-01

    Interest in mechanisms that may control radioelement release from corroded commercial spent nuclear fuel (CSNF) has been heightened by the selection of the Yucca Mountain site in Nevada as the repository for high-level nuclear waste in the United States. Neptunium is an important radionuclide in repository models owing to its relatively long half-life and its high aqueous mobility as neptunyl [Np(V)O+2]. The possibility of neptunium sequestration into uranyl alteration phases produced by corroding CSNF would suggest-a process for lowering neptunium concentration and subsequent migration from a geologic repository. However, there remains little experimental evidence that uranyl compounds will, in fact, serve as long-term host phases for the retention of neptunium under conditions expected in a deep geologic repository. To directly explore this possibility, we examined specimens of uranyl alteration phases derived from humid-air-corroded CSNF by X-ray absorption spectroscopy to better determine neptunium uptake in these phases. Although neptunium fluorescence was readily observed from as-received CSNF, it was not observed from the uranyl alteration rind. We establish upper limits for neptunium incorporation into CSNF alteration phases that are significantly below previously reported concentrations obtained by using electron energy loss spectroscopy (EELS). We attribute the discrepancy to a plural-scattering event that creates a spurious EELS peak at the neptunium-MV energy

  15. Application of Moessbauer spectroscopy to the study of neptunium adsorbed on deep-sea sediments

    International Nuclear Information System (INIS)

    Bennett, B.A.; Rees, L.V.C.

    1987-03-01

    A Neptunium Moessbauer spectrometer (the first in Great Britain) was constructed and the Moessbauer spectra of NpAl Laves phase alloy obtained. Neptunium was sorbed onto a calcareous deep-sea sediment from sea water, using a successive-loading technique. Sorption appeared to be by an equilibrium reaction, and because of the low solubility of neptunium in seawater, this meant that the maximum loading that could be achieved was 8mg 237 Np/g sediment. This proved to be an adequate concentration for Moessbauer measurements and a Moessbauer spectrum was obtained. This showed that most of the neptunium was in exchange sites and not present as precipitates of neptunium compounds. It was probably in the 4+ state indicating that reduction had occurred during sorption. This work has demonstrated that Moessbauer Spectroscopy has great potential as an aid to understanding the mechanism of actinide sorption in natural systems. (author)

  16. Counter-current extraction studies for the recovery of neptunium by the Purex process. Part II

    Energy Technology Data Exchange (ETDEWEB)

    Srinivasan, N.; Nadkarni, M. N.; Kumar, S. V.; Kartha, P. K.S.; Sonavane, R. R.; Ramaniah, M. V.; Patil, S. K.

    1974-07-01

    Counter-extraction experiments were carried out under the conditions relevant to the partitioning column (IBX) in the purex process to know the path of neptunium present as Np (VI) the organic phase during the partitioning step. The results obtained show that when ferrous sulphamates is used as the reducing agent, most of the neptunium continues to remain with uranium in the organic stream while with hydrazine stabilized uranous nitrate as the reducing agent, a major fraction of neptunium follows the aqueous stream. Mixer-settler experiments were also carried out under the conditions relevant to the uranium purification cycle (2D) to establish the conditions for forcing neptunium to the aqueous raffinate or for partitioning it from uranium if both neptunium and uranium are co-extracted in this cycle and the results obtained are reported here. (auth)

  17. Forefront of PUREX system engineering. Chemistry and engineering of ruthenium, technetium and neptunium

    International Nuclear Information System (INIS)

    2004-07-01

    The paper reports the activity of the research committee organized by the Atomic Energy Society of Japan on 'Ruthenium and Technetium Chemistry in the PUREX System', with focusing on basic behaviors of ruthenium, technetium and neptunium in the PUREX process, the principles of plant design, and behaviors during the final waste treatment. The scope of the work includes the following major topics: (1) basic solution and solid-state chemistry; (2) basic solution and solid-state chemistry of minor actinides in particular, Np; (3) partitioning chemistry in the PUREX system and environmental behavior of the components; (4) processes of recovery, purification, and utilization of rare metal fission products; (5) field data on plant design, operation, decontamination, and decommissioning; (6) numerical process simulations and process control technologies; (7) compilation of a data base for process chemistry and plant engineering. (S. Ohno)

  18. Speciation of neptunium during migration in clay rock; Speziation von Neptunium bei der Migration in Tongestein

    Energy Technology Data Exchange (ETDEWEB)

    Froehlich, Daniel

    2011-12-15

    The present work was performed within a fellowship of the interdisciplinary research training group 826 ''trace analysis of elemental species: method development and application'' funded by the German Research Foundation (DFG) and the federal state Rheinland-Pfalz. Aim of this work was to gain new knowledge of the interaction between neptunium and natural clay rock with respect to the disposal of high-level nuclear waste in deep geological formations. The isotope {sup 237}Np with its long half-life of more than two million years will be one of main contributors to the radiotoxicity of the radioactive waste material after storage times of more than 1000 years. In aqueous solution under environmental relevant conditions Np can exist in the oxidation states +IV and +V. Due to its high solubility and higher mobility Np(V) is the much more hazardous species compared to Np(IV). Opalinus Clay (OPA) from Mont Terri, Switzerland, was used as a natural reference material in the migration studies. The focus of this work was on speciation of Np on the mineral surface by synchrotron based X-ray absorption spectroscopy (EXAFS/XANES). The interaction between Np(V) and OPA was studied in batch sorption and diffusion experiments in dependence of various experimental parameters (e.g. pH, temperature, background electrolyte, effect of humic acid, concurrence with U(VI), aerobic/anaerobic conditions). The investigation of Np speciation was performed on two types of samples. Powder samples from batch experiments were prepared under aerobic and anaerobic conditions and measured by EXAFS spectroscopy. Diffusion samples and OPA thin sections contacted with Np(V) were analyzed by locally resolved μ-XANES measurements on enrichments of Np. A combination with μ-XRF (X-ray fluorescence) mapping and μ-XRD (X-ray diffraction) measurements provided further information about the spatial distribution of Np and other elements contained in OPA as well as crystalline mineral

  19. Neptunium and manganese biocycling in nuclear legacy sediment systems

    International Nuclear Information System (INIS)

    Thorpe, Clare L.; Morris, Katherine; Lloyd, Jonathan R.; Denecke, Melissa A.; Law, Kathleen A.; Dardenne, Kathy; Boothman, Christopher; Bots, Pieter; Law, Gareth T.W.

    2015-01-01

    Understanding the behaviour of the highly radiotoxic, long half-life radionuclide neptunium in the environment is important for the management of radioactively contaminated land and the safe disposal of radioactive wastes. Recent studies have identified that microbial reduction can reduce the mobility of neptunium via reduction of soluble Np(V) to poorly soluble Np(IV), with coupling to both Mn- and Fe(III)- reduction implicated in neptunyl reduction. To further explore these processes Mn(IV) as δMnO 2 was added to sediment microcosms to create a sediment microcosm experiment “poised” under Mn-reducing conditions. Enhanced removal of Np(V) from solution occurred during Mn-reduction, and parallel X-ray absorption spectroscopy (XAS) studies confirmed Np(V) reduction to Np(IV) commensurate with microbially-mediated Mn-reduction. Molecular ecology analysis of the XAS systems, which contained up to 0.2 mM Np showed no significant impact of elevated Np concentrations on the microbial population. These results demonstrate the importance of Mn cycling on Np biogeochemistry, and clearly highlight new pathways to reductive immobilisation for this highly radiotoxic actinide. - Highlights: • Neptunium is a high radiotoxicity, alpha emitting actinide. • Biostimulation of Mn(IV)-enriched sediments leads to reductive removal of soluble Np(V) from groundwater onto sediments as Np(IV). • Np(V) reduction occurs under defined Mn-reducing conditions. • Under Mn-reducing conditions, enzymatic processes may be important for Np(V) reduction.

  20. Sorption and migration of neptunium in porous sedimentary materials

    International Nuclear Information System (INIS)

    Tanaka, Tadao; Mukai, Masayuki; Nakayama, Shinichi

    2005-01-01

    Column migration experiments of neptunium were conducted for porous sedimentary materials: coastal sand, tuffaceous sand, ando soil, reddish soil, yellowish soil and loess, and migration behavior, sorption mechanisms and chemical formation of Np were investigated. The migration behavior of Np in each material was much different each other, due to chemical formation in solution and/or sorption mechanism of Np. Mathematical models of different concepts were applied to the experimental results to interpret the sorption mechanism and the migration behavior. It can be concluded that both of instantaneous equilibrium sorption and sorption-desorption kinetics have to be considered to model the Np migration in sedimentary materials. (author)

  1. Absorption, distribution, and fate of neptunium in plants

    International Nuclear Information System (INIS)

    Cataldo, D.A.; Garland, T.R.; Wildung, R.E.

    1988-01-01

    Soil-plant concentration ratios (CR) for neptunium (Np) in bushbean, measured over the range of 5.2 /times/ 10/sup /minus/7/ to 4.1 mg of Np/g of soil, are approximately 2 at soil concentrations below 4 /times/ 10/sup /minus/4/ mg/g and increase to 12 at higher soil levels. The CR values determined for soybean, bushbean, barley, and alfalfa range from 0.5 to 4 at a soil concentration of 2.6 /times/ 10/sup /minus/6/ mg/g. Root absorption by soybean seedlings of Np from solutions containing 7 /times/ 10/sup /minus/7/ to 473 mg of Np(V)/mL is generally proportional to concentration but exhibits some saturation in root absorption at higher concentrations. Seed concentrations in bushbean and wheat are a factor of 10 lower than vegetative tissues. Neptunium is transported within the plant in organic complexes containing one or more organic acid residues. Fractionation of plant tissues indicates that Np is substantially more soluble than plutonium, especially in seeds, with approximately 50% of the soluble Np in roots and leaves associated with plant ligands of less than 5000 molecular weight

  2. Transuranium element chalcogenides. Crystallochemistry and Moessbauer spectrometry of neptunium 237 chalcogenides

    International Nuclear Information System (INIS)

    Thevenin, T.; Pages, M.; Damien, D.

    1981-09-01

    To study actinide compounds , neptunium 237 has been studied by Moessbauer resonance. The different oxidation degrees of neptunium (7, 6, 5, 4 and 3) have a very important effect on isomeric displacements. In the study of chalcogenides, the isomeric displacement value of NpS 3 confirms the valency 4+ of neptunium in this compound. Results obtained with Np 3 S 5 show two valency state +3 and +4 in this compound. There is a good agreement with the two crystalline sites determined by crystallography [fr

  3. Uranium/plutonium and uranium/neptunium separation by the Purex process using hydroxyurea

    International Nuclear Information System (INIS)

    Zhu Zhaowu; He Jianyu; Zhang Zefu; Zhang Yu; Zhu Jianmin; Zhen Weifang

    2004-01-01

    Hydroxyurea dissolved in nitric acid can strip plutonium and neptunium from tri-butyl phosphate efficiently and has little influence on the uranium distribution between the two phases. Simulating the 1B contactor of the Purex process by hydroxyurea with nitric acid solution as a stripping agent, the separation factors of uranium/plutonium and uranium/neptunium can reach values as high as 4.7 x 10 4 and 260, respectively. This indicates that hydroxyurea is a promising salt free agent for uranium/plutonium and uranium/neptunium separations. (author)

  4. Neptunium separation in trace levels from uranium solutions by extraction chromatography

    International Nuclear Information System (INIS)

    Cotrim, M.B.; Matsuda, H.T.

    1994-01-01

    Neptunium and uranium behavior in extraction chromatograph system, aiming the separation of micro quantities of neptunium from uranyl solutions is described. Tri-n-octylamine (TOA), Tri-n-butylphosphate (TBP) as stationary phase, alumine, Voltalef UF-300 as support material were verified. The impregnation conditions as well as the best stationary phase/support material ratio were established. TBP/alumine, TBP/Voltalef and TOA/alumine system were selected to uranium and neptunium separation studies. (author) . 12 refs., 03 tabs., 03 figs

  5. Feasibility Study for Installing Machine in Production Line to Avoid Particle Contamination Based on CFD Simulation

    Science.gov (United States)

    Khaokom, Adisorn; Thongsri, Jatuporn

    2017-10-01

    Ventilation system inside production line for electronic component production needs to meet the factory standard. Because it can eliminate small particles which may cause of human or machine in production as well as it can distribute the circulating air temperature uniformly. CFD is used in this research in order to study the feasibility and plan for machine layout in production line before actual installation. The simulation shows the airflow in every area inside production line. From simulation with releasing the particles from human and machine is found that this ventilation system generates airflow that makes most particles float out of the machines and no particle downs to the conveyor, it results to contamination. In addition, the simulation also shows the range of 19-26 °C air temperature that meets the factory standard. The results of this research are the parts of the data to renovate the production line to get more efficiency and proper on the production.

  6. A contribution to the study of thorium and neptunium (IV) complexes in acidic phosphoric media; Contribution a l`etude des complexes de thorium et de neptunium (IV) en milieux phosphoriques acides

    Energy Technology Data Exchange (ETDEWEB)

    Ghafar, M

    1995-11-30

    The thorium and neptunium (IV) phosphate complexes formation in acidic media has been investigated, essentially at the indicator`s level with {sup 227} Th, {sup 234} Th, {sup 235} Np and {sup 239} Np. Solvent extraction, a commonly used method for determining stability constants in solutions, was used with HDEHP in toluene. In order to get a better understanding of inorganic transparent gels formation in phosphoric aqueous solutions, the effect of the thorium concentration is also studied. Specific experimental conditions have been chosen in order to avoid the formation of chelate and hydrolysis in the aqueous solution. The equilibrium constants and stability constants are calculated, and the results are compared with literature. The results show that increasing the thorium concentration does not lead to polymer forms. refs., 42 figs., 19 tabs.

  7. Solvent-extraction purification of neptunium

    International Nuclear Information System (INIS)

    Kyser, E.A.; Hudlow, S.L.

    2008-01-01

    The Savannah River Site (SRS) has recovered 237 Np from reactor fuel that is currently being processed into NpO 2 for future production of 238 Pu. Several purification flowsheets have been utilized. An oxidizing solvent-extraction (SX) flowsheet was used to remove Fe, sulfate ion, and Th while simultaneously 237 Np, 238 Pu, u, and nonradioactive Ce(IV) was extracted into the tributyl phosphate (TBP) based organic solvent. A reducing SX flowsheet (second pass) removed the Ce and Pu and recovered both Np and U. The oxidizing flowsheet was necessary for solutions that contained excessive amounts of sulfate ion. Anion exchange was used to perform final purification of Np from Pu, U, and various non-actinide impurities. The Np(IV) in the purified solution was then oxalate-precipitated and calcined to an oxide for shipment to other facilities for storage and future target fabrication. Performance details of the SX purification and process difficulties are discussed. (authors)

  8. Rapid and Automated Determination of Plutonium and Neptunium in Environmental Samples

    DEFF Research Database (Denmark)

    Qiao, Jixin

    This thesis presents improved analytical methods for rapid and automated determination of plutonium and neptunium in environmental samples using sequential injection (SI) based chromatography and inductively coupled plasma mass spectrometry (ICP-MS). The progress of methodology development...... and optimization for rapid determination of plutonium in environmental samples using SIextraction chromatography prior to inductively coupled plasma mass spectrometry (Paper III); (3) Development of an SI-chromatographic method for simultaneous determination of plutonium and neptunium in environmental samples...... for rapid and simultaneous determination of plutonium and neptunium within an SI system (Paper VI). The results demonstrate that the developed methods in this study are reliable and efficient for accurate assays of trace levels of plutonium and neptunium as demanded in different situations including...

  9. Counter-current extraction studies for the recovery of neptunium by the Purex process. Part I

    Energy Technology Data Exchange (ETDEWEB)

    Srinivasan, N.; Nadkarni, M. N.; Kumar, S. V.; Kartha, P. K.S.; Sonavane, R. R.; Ramaniah, M. V.; Patil, S. K.

    1974-07-01

    It is proposed to recover neptunium-237, along with uranium and plutonium, during the fuel reprocessing in the PREFRE plant at Tarapur. Counter-current extraction studies, relevant to the code contamination (HA) and partitioning (IA) cycles of the purex process, were carried out to arrive at suitable chemical flowsheet conditions which would enable the co-extraction of neptunium along with uranium and plutonium. The results of the studies carried out using a laboratory mixer-settler unit and synthetic mixtures of neptunium and uranium are reported here. Based on these results, the chemical flowsheet conditions are proposed for the co-extraction of neptunium even if it exists as Np(V) in the aqueous feed solution. (auth)

  10. Selective localization of neptunium-237 in the nuclei of mammalian cells. Localisation selective du neptunium-237 au sein des noyaux des cellules de mammiferes

    Energy Technology Data Exchange (ETDEWEB)

    Galle, P.; Boulahdour, H. (Faculte de Medecine, 94 - Creteil (FR)); Metivier, H. (CEA Centre d' Etudes Nucleaires de Fontenay-aux-Roses, 92 (FR). Inst. de Protection et de Surete Nucleaire)

    1992-01-01

    After injection in the rat of soluble neptunium salt, the distribution of this element was studied at the subcellular level by electron microscopy and electron probe microanalysis. Abnormal structures have been observed by electron microscopy in the nuclei of hepatocytes, and the same structures have also been observed in the nuclei of the proximal tubules cells of the kidney. These structures are formed of clusters of very small and dense particles, several nanometers in diameter. The clusters are localized in the central part of the nuclei and they are separate from nucleoli and heterochromatin. Electron probe X-ray analysis of this cluster have shown that they contain neptunium associated with phosphorus. In the cell containing neptunium inclusions, other non specific lesions are also observed (nuclear pycnosis, mitochondrial depletion).

  11. Mechanisms of sorption of neptunium and technetium on argillaceous materials

    International Nuclear Information System (INIS)

    Hooker, P.J.; West, J.M.; Noy, D.J.

    1986-01-01

    It is of pressing concern to understand the behaviour of radionuclides in the environment and in particular long-lived ones (e.g. Np-237 and Te-99) in argillaceous rocks. Clay formations have been chosen as likely candidates for holding low level radioactive waste repositories and in the event of leakage of radionuclides into the geosphere some knowledge of their fate is required in a far-field safety assessment study. The objectives of this present work were to examine the properties of neptunium and technetium in ground-waters associated with clay-rich materials and to ascertain the variations in sorption of these radionuclides under different environmental conditions and to use the information in a forecast of transport through a clay layer

  12. Nuclear forensics of a non-traditional sample: Neptunium

    International Nuclear Information System (INIS)

    Doyle, Jamie L.; Schwartz, Daniel; Tandon, Lav

    2016-01-01

    Recent nuclear forensics cases have focused primarily on plutonium (Pu) and uranium (U) materials. By definition however, nuclear forensics can apply to any diverted nuclear material. This includes neptunium (Np), an internationally safeguarded material like Pu and U, that could offer a nuclear security concern if significant quantities were found outside of regulatory control. This case study couples scanning electron microscopy (SEM) with quantitative analysis using newly developed specialized software, to evaluate a non-traditional nuclear forensic sample of Np. Here, the results of the morphological analyses were compared with another Np sample of known pedigree, as well as other traditional actinide materials in order to determine potential processing and point-of-origin

  13. Photochemical reactions of neptunium in nitric acid solution containing photocatalyst

    International Nuclear Information System (INIS)

    Fukasawa, Tetsuo; Kawamura, Fumio

    1991-01-01

    Photochemical oxidation and reduction behaviors of neptunium were preliminarily investigated in 3 mol/l nitric acid solution. Nitric acid of 3 mol/l simulated the high level waste solution from a spent fuel reprocessing process. Concentrations of Np(V), Np(VI) and nitrous acid were determined with a photospectrometer, and solution potential with an electrode. Without additives, Np(VI) was reduced to Np(V) by nitrous acid which was photolytically generated from nitric acid. With a scavenger for nitrous acid, Np(V) was oxidized to extractable Np(VI) by a photolytically generated oxidizing reagent which were predicted by the solution potential measurement. The reduction rate was higher than the oxidation rate because of the larger quantity and higher reactivity of nitrous acid than an oxidizing reagent. Photocatalyst was proved to be effective for the oxidation of Np(V) to Np(VI). (author)

  14. Neptunium detector using fiber-optic light guides

    International Nuclear Information System (INIS)

    Spencer, W.A.; Killeen, T.E.; Herold, T.R.

    1981-01-01

    A colorimeter has been constructed and installed to detect neptunium (IV) on-line as it elutes from an ion exchange column in a plant process stream. Because of the high radiation and corrosive atmosphere at the monitoring location, the instrument was designed using remote electronics and glass fiber optic cables. The five-foot cables transmit pulsed white light into a glass monitoring window in a containment box and return the transmitted portion to a photosensor. A simple spring clamp was designed to couple the cables to the monitoring window without modifying existing processes. Details of the design, installation, and operational problems are discussed. Other applications and modifications of the present colorimeter for other actinides, as well as preliminary results on a fiber optic spectrophotometer, are presented

  15. Geomicrobiological redox cycling of the transuranic element neptunium.

    Science.gov (United States)

    Law, Gareth T W; Geissler, Andrea; Lloyd, Jonathan R; Livens, Francis R; Boothman, Christopher; Begg, James D C; Denecke, Melissa A; Rothe, Jörg; Dardenne, Kathy; Burke, Ian T; Charnock, John M; Morris, Katherine

    2010-12-01

    Microbial processes can affect the environmental behavior of redox sensitive radionuclides, and understanding these reactions is essential for the safe management of radioactive wastes. Neptunium, an alpha-emitting transuranic element, is of particular importance because of its long half-life, high radiotoxicity, and relatively high solubility as Np(V)O(2)(+) under oxic conditions. Here, we describe experiments to explore the biogeochemistry of Np where Np(V) was added to oxic sediment microcosms with indigenous microorganisms and anaerobically incubated. Enhanced Np removal to sediments occurred during microbially mediated metal reduction, and X-ray absorption spectroscopy showed this was due to reduction to poorly soluble Np(IV) on solids. In subsequent reoxidation experiments, sediment-associated Np(IV) was somewhat resistant to oxidative remobilization. These results demonstrate the influence of microbial processes on Np solubility and highlight the critical importance of radionuclide biogeochemistry in nuclear legacy management.

  16. Electroanalytical studies of uranium, neptunium, and plutonium ions in solutions

    International Nuclear Information System (INIS)

    Yoshida, Zenko; Aoyagi, Hisao; Kihara, Sorin

    1989-01-01

    Redox behavior of uranium, neptunium, and plutonium ions, whose oxidation states in acid solutions are between (VI) and (III), were investigated by flow-coulometry with a column electrode of glassy carbon fibers as well as ordinary voltammetry with a rotating disc electrode. Based on current-potential curves the electrode processes were elucidated taking their disproportionation and/or complexation reactions into account. The flow-coulometry, which provides rapid and quantitative electrolysis, was applied to such analytical purposes as follows; the determination of uranium and plutonium in the solution or the solid with discerning their oxidation states, the preparation of species in a desired oxidation state, even in an unstable state which cannot be prepared by ordinary procedure, and the separation of trace amount of uranium in solutions by the electrodeposition of its hydroxide

  17. Diffusion of water, cesium and neptunium in pores of rocks

    International Nuclear Information System (INIS)

    Puukko, E.; Heikkinen, T.; Hakanen, M.

    1993-10-01

    Teollisuuden Voima Oy (TVO) is investigating the feasibility to dispose of spent nuclear fuel within Finland. The present plan calls for the repository to be located in crystalline rock at a depth of several hundred meters. The safety assessment of the repository includes calculations of migration of waste nuclides. The flow of waste elements in groundwater will be retarded through sorption interaction with minerals and through diffusion into rock. Diffusion is the only mechanism retarding the migration of non-sorbing species and, it is expected to be the dominating retardation mechanism of many of the sorbing elements. In the investigation the simultaneous diffusion of tritiated water (HTO), cesium and neptunium in rocks of TVO investigation sites at Kivetty, Olkiluoto and Romuvaara were studied. (11 refs., 33 figs., 9 tabs.)

  18. Pressure effects on magnetism in the uranium and neptunium monopnictides

    International Nuclear Information System (INIS)

    Braithwaite, D.; Demuer, A.; Ichas, V.; Rebizant, J.; Spirlet, J.C.; Zwirner, S.; Vogt, O.

    1998-01-01

    The magnetic properties of the cubic NaCl uranium and neptunium monopnictides (UX, NpX; X=N, P, As, Sb, Bi) have been widely studied at ambient pressure. Properties ranging from itinerant to localized magnetism, and a variety of ordered magnetic structures have been observed. In particular the profusion of non-collinear double-k or triple-k structures is a consequence of strongly anisotropic exchange interactions. The application of pressure is a clean way of continuously varying the lattice parameter, and the exchange interactions, from one compound to another. A number of studies have been performed using different high pressure techniques. Some of the effects of pressure can be understood in a simple picture of a continuous variation of the lattice parameter, but some highly anomalous effects are also found which are discussed in relation to the possible nature of the magnetic interactions. (orig.)

  19. Reduction and precipitation of neptunium(V) by sulfate-reducing bacteria

    International Nuclear Information System (INIS)

    Banaszak, J. E.; Rittmann, B. E.; Reed, D. T.

    1999-01-01

    Migration of neptunium, as NpO 2 + , has been identified as a potentially important pathway for actinide release at nuclear waste repositories and existing sites of subsurface contamination. Reduction of Np(V) to Np(IV) will likely reduce its volubility, resulting in lowered subsurface migration. The ability of sulfate-reducing bacteria (SRB) to utilize Np(V) as an electron acceptor was investigated, because these bacteria are active in many anaerobic aquifers and are known to facilitate the reduction of metals and radionuclides. Pure and mixed cultures of SRB were able to precipitate neptunium during utilization of pyruvate, lactate, and hydrogen as electron donors in the presence and absence of sulfate. The neptunium in the precipitate was identified as Np(IV) using X-ray absorption near edge spectroscopy (XANES) analysis. In mixed-culture studies, the addition of hydrogen to consortia grown by pyruvate fermentation stimulated neptunium reduction and precipitation. Experiments with pure cultures of Desulfovibrio vulgaris, growing by lactate fermentation in the absence of sulfate or by sulfate reduction, confirm that the organism is active in neptunium reduction and precipitation. Based on our results, the activity of SRB in the subsurface may have a significant, and potentially beneficial, impact on actinide mobility by reducing neptunium volubility

  20. Technetium and neptunium reactions in basalt/groundwater systems

    International Nuclear Information System (INIS)

    Meyer, R.E.; Arnold, W.D.; Kelmers, A.D.; Kessler, J.H.; Clark, R.J.; Johnson, J.S. Jr.; Young, G.C.; Case, F.I.; Westmoreland, C.G.

    1985-01-01

    Sorption isotherms and apparent concentration limits for Tc(VII) and Np(V) for a variety of groundwater/basalt systems were determined using Grande Ronde basalt samples representative of the Hanford Site candidate high-level waste repository. Under oxic redox conditions (air present), little or no sorption of technetium was observed; neptunium exhibited low to moderate sorption ratios. Under anoxic redox conditions (oxygen-free), low to moderate sorption of technetium was often observed, but the extent of sorption was highly dependent upon the groundwater composition and the method of pretreatment (if any) of the basalt. Sorption isotherms for technetium under reducing redox conditions (hydrazine added) indicate an apparent concentration limit of approximately 10 -6 mol/l Tc. No apparent concentration limit was found for neptunium for concentrations in groundwater up to 10 -6 mol/l and 8 x 10 -7 mol/l under oxic and reducing (hydrazine added) redox conditions, respectively. Valence control and valence analysis experiments suggest that the sorption or precipitation of Tc and Np from groundwater in the presence of basalt may result from a heterogeneous reaction occurring on the surface of the basalt. One of the critical factors of this reduction reaction appears to be the accessibility of the reactive ferrous iron component of the basalt. The laboratory simulation of groundwater redox conditions representative of the repository environment through the use of solution phase redox reagents is of questionable validity, and information obtained by such experimental methods may not be defensible for site performance assessment calculations. Anoxic experiments conducted in an argon-filled glove box appear better suited for the laboratory simulation of in situ redox conditions. 15 references, 6 figures

  1. Technetium and neptunium reactions in basalt/groundwater systems

    International Nuclear Information System (INIS)

    Meyer, R.E.; Arnold, W.D.; Kelmers, A.D.; Kessler, J.H.; Clark, R.J.; Johnson, J.S. Jr.; Young, G.C.; Case, F.I.; Westmoreland, C.G.; Florida State Univ., Tallahassee)

    1984-01-01

    Sorption isotherms and apparent concentration limits for Tc(VII) and Np(V) for a variety of groundwater/basalt systems were determined using Grande Ronde basalt samples representative of the Hanford Site candidate high-level waste repository. Under oxic redox conditions (air present), little or no sorption of technetium was observed; neptunium exhibited low to moderate sorption ratios. Under anoxic redox conditions (oxygen-free), low to moderate sorption of technetium was often observed, but the extent of sorption was highly dependent upon the groundwater composition and the method of pretreatment (if any) of the basalt. Sorption isotherms for technetium under reducing redox conditions (hydrazine added) indicate an apparent concentration limit of approximately 10 -6 mol/L Tc. No apparent concentration limit was found for neptunium for concentrations in groundwater up to approx. 10 -6 mol/L and 8 x 10 -7 mol/L under oxic and reducing (hydrazine added) redox conditions, respectively. Valence control and valence analysis experiments suggest that the sorption or precipitation of Tc and Np from groundwater in the presence of basalt may result from a heterogeneous reaction occurring on the surface of the basalt. One of the critical factors of this reduction reaction appears to be the accessibility of the reactive ferrous iron component of the basalt. The laboratory simulation of groundwater redox conditions representative of the repository environment through the use of solution phase redox reagents is of questionable validity, and information obtained by such experimental methods may not be defensible for site performance assessment calculations. Anoxic experiments conducted in an argon-filled glove box appear better suited for the laboratory simulation of in situ redox conditions. 15 refs., 6 tabs

  2. Spatial Trade-Offs between Wind Power Production and Bird Collision Avoidance in Agricultural Landscapes

    Directory of Open Access Journals (Sweden)

    Marcus Eichhorn

    2010-06-01

    Full Text Available The expansion of renewable energy production is seen as an appropriate way to mitigate climate change. Renewable energies are not free of negative external effects on humans and the natural environment. We analyzed the conflict between wind power production and bird protection through the example of one of the most sensitive species, the red kite (Milvus milvus in West Saxony, Germany. We investigated a large number of potential land use scenarios, defined by whether or not each potential site contained a wind turbine (WT. Based on meteorological and ornithological data, we evaluated the land use scenarios for their annual energy supply and impact on the red kite. We identified the efficient land use scenarios that maximized energy supply for a given ecological impact. Within the scope of our analysis, the current allocation of WTs in the study region was considered inefficient. The set of efficient scenarios allowed us to draw conclusions on the trade-offs involved. We developed an indicator that measures the severity of the conflict between wind power production and bird protection. Increasing the minimum distance of WTs to settlements beyond the legal requirements in order to minimize the impact on humans further intensifies the conflict. Our results can support planning authorities in their development of long-term regional plans by identifying areas that are most suitable for wind power production from an integrated point of view.

  3. Green Toxicology-Know Early About and Avoid Toxic Product Liabilities.

    Science.gov (United States)

    Maertens, Alexandra; Hartung, Thomas

    2018-02-01

    Toxicology uniquely among the life sciences relies largely on methods which are more than 40-years old. Over the last 3 decades with more or less success some additions to and few replacements in this toolbox took place, mainly as alternatives to animal testing. The acceptance of such new approaches faces the needs of formal validation and the conservative attitude toward change in safety assessments. Only recently, there is growing awareness that the same alternative methods, especially in silico and in vitro tools can also much earlier and before validation inform decision-taking in the product life cycle. As similar thoughts developed in the context of Green Chemistry, the term of Green Toxicology was coined to describe this change in approach. Here, the current developments in the alternative field, especially computational and more organo-typic cell cultures are reviewed, as they lend themselves to front-loaded chemical safety assessments. The initiatives of the Center for Alternatives to Animal Testing Green Toxicology Collaboration are presented. They aim first of all for forming a community to promote this concept and then for a cultural change in companies with the necessary training of chemists, product stewards and later regulators. © The Author 2017. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  4. The metabolism and gastrointestinal absorption of neptunium and protactinium in adult baboons

    International Nuclear Information System (INIS)

    Ralston, L.G.; Cohen, N.; Bhattacharyya, H.; Larsen, R.P.; Ayres, L.; Oldham, R.D.; Moretti, E.S.

    1985-01-01

    The metabolism of neptunium and protactinium was studied in adult female baboons following intravenous injection and intragastric intubation. Neptunium-239, Np-237, and Pa-233 were prepared as either citrate-buffer, nitrate, or bicarbonate solutions with oxidation states of (V) and (VI). Samples of blood, urine, feces and autopsy tissues were measured by gamma spectrometry. Retention of neptunium and protactinium was determined in vivo using whole and partial body gamma-scintillation spectrometry with [NaI-CsI(T1)] detectors. Fed and fasted baboons were administered solutions of Np(VI) bicarbonate (10/sup -8/ to 10/sup -1/ mg/kg) and Pa(V) citrate-buffer (10/sup -9/ mg/kg) by gavage. The gastrointestinal absorption value for neptunium in two fasted baboons, sacrificed at 1 day post administration, was determined to be 0.92 +- 0.04%. Of the total amount of neptunium absorbed, 52 +- 3% was retained in bone, 6 + 2% was in liver, and 42 +- 0.1% was excreted in urine. The metabolism of neptunium followed oral and iv administrations was found to be similar. This observation was also true for baboons which had received oral and iv doses of protactinium. A method was developed to estimate GI absorption values for both nuclides in baboons, which were not sacrificed, by comparison of activities present in bioassay samples after injection and gavage. Absorption values calculated by this method for neptunium and protactinium in fasted baboons were 1.8 +- 0.8% and 0.65 +- 0.01%, respectively. Values for fed animals were 1 to 2 orders of magnitude less than those for fasted animals. Further experiments are currently underway to evaluate this assay technique

  5. Metabolism and gastrointestinal absorption of neptunium and protactinium in adult baboons

    International Nuclear Information System (INIS)

    Ralston, L.G.; Cohen, N.; Bhattacharyya, M.H.; Larsen, R.P.; Ayres, L.; Oldham, R.D.; Moretti, E.S.

    1985-01-01

    The metabolism of neptunium and protactinium was studied in adult female baboons following intravenous injection and intragastric intubation. Immediately following intravenous injection (10 -1 to 10 -10 mg Np per kg body wt), neptunium cleared rapidly from blood, deposited primarily in the skeleton (54 +- 5%) and liver (3 +- 0.2%), and was excreted predominantly via urine (40 +- 3%). For the first year post injection, neptunium was retained with a biological half-time of approx.100 days in liver and 1.5 +- 0.2 yr in bone. In comparison, injected protactinium (10 -9 mg/kg) was retained in blood in higher concentrations and was initially eliminated in urine to a lesser extent (6 +- 3%). In vivo measurements indicated that protactinium was retained in bone (65 +- 0.3%) with a half-time of 3.5 +- 0.6 yr. Differences in the physicochemical states of the neptunium or protactinium solutions injected did not alter the metabolic behavior of these nuclides. The gastrointestinal absorption value for neptunium in two fasted baboons, sacrificed at 1 day post administration, was determined to be 0.92 +- 0.04%. Of the total amount of neptunium absorbed, 52 +- 3% was retained in bone, 6 +- 2% was in liver, and 42 +- 0.1% was excreted in urine. A method was developed to estimate GI absorption values for both nuclides in baboons which were not sacrificed. Absorption values calculated by this method for neptunium and protactinium in fasted baboons were 1.8 +- 0.8% and 0.65 +- 0.01%, respectively. Values for fed animals were 1 to 2 orders of magnitude less than those for fasted animals. 14 refs., 3 figs., 4 tabs. (DT)

  6. Metabolism and gastrointestinal absorption of neptunium and protactinium in adult baboons

    Energy Technology Data Exchange (ETDEWEB)

    Ralston, L.G.; Cohen, N.; Bhattacharyya, M.H.; Larsen, R.P.; Ayres, L.; Oldham, R.D.; Moretti, E.S.

    1985-01-01

    The metabolism of neptunium and protactinium was studied in adult female baboons following intravenous injection and intragastric intubation. Immediately following intravenous injection (10/sup -1/ to 10/sup -10/ mg Np per kg body wt), neptunium cleared rapidly from blood, deposited primarily in the skeleton (54 +- 5%) and liver (3 +- 0.2%), and was excreted predominantly via urine (40 +- 3%). For the first year post injection, neptunium was retained with a biological half-time of approx.100 days in liver and 1.5 +- 0.2 yr in bone. In comparison, injected protactinium (10/sup -9/ mg/kg) was retained in blood in higher concentrations and was initially eliminated in urine to a lesser extent (6 +- 3%). In vivo measurements indicated that protactinium was retained in bone (65 +- 0.3%) with a half-time of 3.5 +- 0.6 yr. Differences in the physicochemical states of the neptunium or protactinium solutions injected did not alter the metabolic behavior of these nuclides. The gastrointestinal absorption value for neptunium in two fasted baboons, sacrificed at 1 day post administration, was determined to be 0.92 +- 0.04%. Of the total amount of neptunium absorbed, 52 +- 3% was retained in bone, 6 +- 2% was in liver, and 42 +- 0.1% was excreted in urine. A method was developed to estimate GI absorption values for both nuclides in baboons which were not sacrificed. Absorption values calculated by this method for neptunium and protactinium in fasted baboons were 1.8 +- 0.8% and 0.65 +- 0.01%, respectively. Values for fed animals were 1 to 2 orders of magnitude less than those for fasted animals. 14 refs., 3 figs., 4 tabs. (DT)

  7. The effect of high ionic strength on neptunium (V) adsorption to a halophilic bacterium

    Science.gov (United States)

    Ams, David A.; Swanson, Juliet S.; Szymanowski, Jennifer E. S.; Fein, Jeremy B.; Richmann, Michael; Reed, Donald T.

    2013-06-01

    The mobility of neptunium (V) in subsurface high ionic strength aqueous systems may be strongly influenced by adsorption to the cell wall of the halophilic bacteria Chromohalobacter sp. This study is the first to evaluate the adsorption of neptunium (V) to the surface of a halophilic bacterium as a function of pH from approximately 2 to 10 and at ionic strengths of 2 and 4 M. This is also the first study to evaluate the effects of carbonate complexation with neptunium (V) on adsorption to whole bacterial cells under high pH conditions. A thermodynamically-based surface complexation model was adapted to describe experimental adsorption data under high ionic strength conditions where traditional corrections for aqueous ion activity are invalid. Adsorption of neptunium (V) was rapid and reversible under the conditions of the study. Adsorption was significant over the entire pH range evaluated for both ionic strength conditions and was shown to be dependent on the speciation of the sites on the bacterial surface and neptunium (V) in solution. Adsorption behavior was controlled by the relatively strong electrostatic attraction of the positively charged neptunyl ion to the negatively charged bacterial surface at pH below circum-neutral. At pH above circum-neutral, the adsorption behavior was controlled by the presence of negatively charged neptunium (V) carbonate complexes resulting in decreased adsorption, although adsorption was still significant due to the adsorption of negatively charged neptunyl-carbonate species. Adsorption in 4 M NaClO4 was enhanced relative to adsorption in 2 M NaClO4 over the majority of the pH range evaluated, likely due to the effect of increasing aqueous ion activity at high ionic strength. The protonation/deprotonation characteristics of the cell wall of Chromohalobacter sp. were evaluated by potentiometric titrations in 2 and 4 M NaClO4. Bacterial titration results indicated that Chromohalobacter sp. exhibits similar proton buffering

  8. Investigation of composition and properties of some neptunium (5) oxalate compounds

    International Nuclear Information System (INIS)

    Zubarev, V.G.; Krot, N.N.

    1981-01-01

    A simple way of neptunium (5) oxalate synthesis is described and its composition is determined: (NpO 2 ) 2 C 2 O 4 xH 2 O. The compound is precipitated from solution during pouring together stoichiometric quantities of neptunium (5) nitrate and ammonium, sodium or potassium oxalate at pH=4-5. An explanation to unusual effect of solubility change with time of neptunium (5) monooxalate complexes and alkali metal or ammonium ion is found taking into account the slow formation of precipitate and low solubility of the compound obtained (0.62 g/l as to metal). Thermal decomposition of the compound is studied. At 180 deg C a water molecule is split off and at 260 deg C decomposition of neptunium oxalate starts. IR spectra and interplane distances (dsub(hkl)) of the compound crystal lattice are determined. New data on the synthesis and properties of complex neptunium (5) oxalates and monovalent cation in second sphere with the ratio ligand: metal=2:1 and 3:1 are presented. On the basis of results of IR spectroscopy and X-ray phase analyses a supposition is made on the existence of such complex compounds [ru

  9. Rapid and automated determination of plutonium and neptunium in environmental samples

    International Nuclear Information System (INIS)

    Qiao, J.

    2011-03-01

    This thesis presents improved analytical methods for rapid and automated determination of plutonium and neptunium in environmental samples using sequential injection (SI) based chromatography and inductively coupled plasma mass spectrometry (ICP-MS). The progress of methodology development in this work consists of 5 subjects stated as follows: 1) Development and optimization of an SI-anion exchange chromatographic method for rapid determination of plutonium in environmental samples in combination of inductively coupled plasma mass spectrometry detection (Paper II); (2) Methodology development and optimization for rapid determination of plutonium in environmental samples using SI-extraction chromatography prior to inductively coupled plasma mass spectrometry (Paper III); (3) Development of an SI-chromatographic method for simultaneous determination of plutonium and neptunium in environmental samples (Paper IV); (4) Investigation of the suitability and applicability of 242 Pu as a tracer for rapid neptunium determination using anion exchange chromatography in an SI-network coupled with inductively coupled plasma mass spectrometry (Paper V); (5) Exploration of macro-porous anion exchange chromatography for rapid and simultaneous determination of plutonium and neptunium within an SI system (Paper VI). The results demonstrate that the developed methods in this study are reliable and efficient for accurate assays of trace levels of plutonium and neptunium as demanded in different situations including environmental risk monitoring and assessment, emergency preparedness and surveillance of contaminated areas. (Author)

  10. Rapid and automated determination of plutonium and neptunium in environmental samples

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, J.

    2011-03-15

    This thesis presents improved analytical methods for rapid and automated determination of plutonium and neptunium in environmental samples using sequential injection (SI) based chromatography and inductively coupled plasma mass spectrometry (ICP-MS). The progress of methodology development in this work consists of 5 subjects stated as follows: 1) Development and optimization of an SI-anion exchange chromatographic method for rapid determination of plutonium in environmental samples in combination of inductively coupled plasma mass spectrometry detection (Paper II); (2) Methodology development and optimization for rapid determination of plutonium in environmental samples using SI-extraction chromatography prior to inductively coupled plasma mass spectrometry (Paper III); (3) Development of an SI-chromatographic method for simultaneous determination of plutonium and neptunium in environmental samples (Paper IV); (4) Investigation of the suitability and applicability of 242Pu as a tracer for rapid neptunium determination using anion exchange chromatography in an SI-network coupled with inductively coupled plasma mass spectrometry (Paper V); (5) Exploration of macro-porous anion exchange chromatography for rapid and simultaneous determination of plutonium and neptunium within an SI system (Paper VI). The results demonstrate that the developed methods in this study are reliable and efficient for accurate assays of trace levels of plutonium and neptunium as demanded in different situations including environmental risk monitoring and assessment, emergency preparedness and surveillance of contaminated areas. (Author)

  11. Energy efficiency of neptunium redox battery in comparison with vanadium battery

    International Nuclear Information System (INIS)

    Yamamura, T.; Watanabe, N.; Shiokawa, Y.

    2006-01-01

    A neptunium ion possesses two isostructural and reversible redox couples (Np 3+ /Np 4+ and NpO 2 + /NpO 2 2+ ) and is therefore suitable as an active material for a redox-flow battery. Since the plastic formed carbon (PFC) is known to show the largest k values for Np(IV)/Np(III) and Np(V)/Np(VI) reactions among various carbon electrodes, a cell was constructed by using the PFC, with the circulation induced by bubbling gas through the electrolyte. In discharge experiments with a neptunium and a vanadium battery using the cell, the former showed a lower voltage loss which suggests a smaller reaction overvoltage. Because of the high radioactivity of the neptunium, it was difficult to obtain sufficient circulation required for the redox-flow battery, therefore a model for evaluating the energy efficiency of the redox-flow battery was developed. By using the known k values for neptunium and vanadium electrode reactions at PFC electrodes, the energy efficiency of the neptunium battery was calculated to be 99.1% at 70 mA cm -2 , which exceeds that of the vanadium battery by ca. 16%

  12. An assessment of the thermodynamic behaviour of neptunium in water and model groundwaters from 25 to 150 degrees C

    International Nuclear Information System (INIS)

    Lemire, R.J.

    1984-03-01

    Standard molal Gibbs energy of formation and entropy data for simple neptunium solids and aqueous neptunium complexes with OH - , Cl - , F - , CO 3 2- , PO 4 3- , SO-4 2- and Na + have been critically reviewed. Selected values are used with estimated heat capacity values to derive self-consistent analytical expressions for the temperature dependence of the standard molal Gibbs energies of formation of the species from 25 to 150 degrees C. The Gibbs energies have been used to evaluate the effect of different concentrations of ligands on the solubility of neptunium solids as a function of temperature. Potential-pH diagrams are given for neptunium in pure water and in two model groundwaters. Important deficiencies in the available thermodynamic data for neptunium species are discussed

  13. Assessment of the thermodynamic behavior of neptunium in water and model groundwaters from 25 to 150/sup 0/C

    Energy Technology Data Exchange (ETDEWEB)

    Lemire, R J

    1984-03-15

    Standard molal Gibbs energy of formation and entropy data for simple neptunium solids and aqueous neptunium complexes with OH/sup -/, Cl/sup -/, F/sup -/, CO/sub 3//sup 2 -/, PO/sub 4//sup 3 -/, SO/sub 4//sup 2 -/ and Na/sup +/ have been critically reviewed. Selected values are used with estimated heat capacity values to derive self-consistent analytical expressions for the temperature dependence of the standard molal Gibbs energies of formation of the species from 25 to 150/sup 0/C. The Gibbs energies have been used to evaluate the effect of different concentrations of ligands on the solubility of neptunium solids as a function of temperature. Potential-pH diagrams are given for neptunium in pure water and in two model groundwaters. Important deficiencies in the available thermodynamic data for neptunium species are discussed. 90 references, 12 figures, 6 tables.

  14. Quaternary ammonium based task specific ionic liquid for the efficient and selective extraction of neptunium

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Nishesh Kumar [National Institute of Technology, Odisha (India). Dept. of Chemistry; Sengupta, Arijit [Bhabha Atomic Research Centre, Mumbai (India). Radiochemistry Div.; Biswas, Sujoy [Bhabha Atomic Research Centre, Mumbai (India). Uranium Extraction Div.

    2017-07-01

    Liquid-liquid extraction of neptunium from aqueous acidic solution using quaternary ammonium based task specific ionic liquid (TSIL) was investigated. The extraction of Np was predominated by the 'cation exchange' mechanism via [NpO{sub 2}.Hpth]{sup +} species for NpO{sub 2}{sup 2+}, while NpO{sub 2}{sup +} was extracted in ionic liquid as [NpO{sub 2}.H.Hpth]{sup +}. The extraction process was thermodynamically spontaneous while kinetically slower. Na{sub 2}CO{sub 3} as strippant showed quantitative back extraction of neptunium ions from TSIL. TSIL showed excellent radiolytic stability upto 500 kGy gamma exposure. Finally, the TSIL was employed for the processing of simulated high level waste solutions revealing high selectivity of TSIL towards neptunium.

  15. Coprecipitation of neptunium and plutonium with iron and zirconium dibutyl phosphates

    International Nuclear Information System (INIS)

    Sokhina, L.P.; Rovnyj, S.I.; Goncharuk, L.V.

    1988-01-01

    Neptunium and plutonium coprecipitation with precipitates of dibutyl phosphates of some elements significant for radiochemical technology is studied. By the ability to coprecipitation of actinides with precipitates of dibutyl phosphates the cations may be arranged in the series Fe > Al > La > ≥ Zr ≥ Th. The composition of neptunium and plutonium mixed precipitates on the basis of iron dibutyl phosphates corresponding to the formula (Me(NO 3 ) 2 Al 2 ) n x · FeA 3 , where Me-neptunium or plutonium, A-anion of dibutyl phosphoric acid, n=1-4, is determined. Solubility of mixed precipitations in nitric acid and carbonate solutions is studied. Mixed precipitations on the basis of iron dibutyl phosphates are found to have the least solubility, their solubility being lower than that of individual compounds of dibutyl phoshates. The mechanism of formation of mixed precipitates is suggested and discussed

  16. The XPS study of physical and chemical forms of neptunium group on the surface of minerals

    Directory of Open Access Journals (Sweden)

    Teterin Anton Yu.

    2010-01-01

    Full Text Available The sorption behavior and the physical and chemical forms of neptunium on the surface of minerals of the two chlorate samples, biotite and kaolin, with different contents of Fe(II was studied. The liquid-liquid extraction and the X-ray photoelectron spectroscopy were employed to identify the valence forms of neptunium. On the basis of the obtained data the quantitative elemental composition of the surface of the studied minerals, as well as the ionic composition of the formed neptunium complexes was determined. It was shown that the Np(IV and Np(VI containing compounds did not form, while the complexes Np(VO+ -hydroxyl did form on the surface. The oxygen ions bonded with iron and oxygen belonging to water and/or of carboxyl were suggested to be present in the equatorial plane of the neptunyl group NpO+.

  17. Neptunium-the neglected actinide: a review of the biological and environmental literature

    International Nuclear Information System (INIS)

    Thompson, R.C.

    1982-01-01

    Data from 89 references relating to the biological and environmental behavior of neptunium are reviewed with particular attention to the potential risks from possible releases of neptunium isotopes by the nuclear industry. The behavior of neptunium differs in many significant respects from that of other transuranic elements. It is more mobile environmentally and more readily absorbed by man, although some of the higher reported values for gastrointestinal absorption appear to have been influenced by the very high mass levels of 237 Np required for experimental study. In studies with experimental animals its ratio of deposition in bone/liver is greater than that of other transuranic elements. Its long-term toxicity in experimental animals is similar to that of other transuranics

  18. Measurement of total alpha activity of neptunium, plutonium, and americium in highly radioactive Hanford waste by iron hydroxide precipitation and 2-heptanone solvent extraction

    International Nuclear Information System (INIS)

    Maiti, T.C.; Kaye, J.H.

    1992-06-01

    An improved method has been developed to concentrate the major alpha-emitting actinide elements neptunium, plutonium, and americium from samples with high salt content such as those resulting from efforts to characterize Hanford storage tank waste. Actinide elements are concentrated by coprecipitation of their hydroxides using iron carrier. The iron is removed by extraction from 8M HCI with 2-heptanone. The actinide elements remain in the aqueous phase free from salts, iron, and long-lived fission products. Recoveries averaged 98 percent

  19. Factors Controlling Redox Speciation of Plutonium and Neptunium in Extraction Separation Processes

    Energy Technology Data Exchange (ETDEWEB)

    Paulenova, Alena [Principal Investigator; Vandegrift, III, George F. [Collaborator

    2013-09-24

    The objective of the project was to examine the factors controlling redox speciation of plutonium and neptunium in UREX+ extraction in terms of redox potentials, redox mechanism, kinetics and thermodynamics. Researchers employed redox-speciation extractions schemes in parallel to the spectroscopic experiments. The resulting distribution of redox species w studied uring spectroscopic, electrochemical, and spectro-electrochemical methods. This work reulted in collection of data on redox stability and distribution of redox couples in the nitric acid/nitrate electrolyte and the development of redox buffers to stabilize the desired oxidation state of separated radionuclides. The effects of temperature and concentrations on the redox behavior of neptunium were evaluated.

  20. Selective leaching studies of deep-sea sediments loaded with americium, neptunium and plutonium

    International Nuclear Information System (INIS)

    Cole, T.G.; Higgo, J.J.W.; Cronan, D.S.; Rees, L.V.C.

    1984-07-01

    A series of selective leaching experiments were undertaken to investigate the solid phase speciation and distribution of americium, neptunium and plutonium which had been experimentally loaded onto different marine sediment types. The chemical leaches employed showed rather poor selectivity but certain trends were evident. Adsorption was not by ion exchange. Americium showed a preferential affinity for carbonate and plutonium for organic matter. Neptunium appeared to have no preferential affinities. Americium was sorbed by acetic acid residues (CaCO 3 removed) and by unleached carbonate-rich sediments with equal efficiency. This indicates that it is able to diversify its solid phase affinity/distribution depending upon which solid phases are available. (author)

  1. Experimental study on neptunium migration under in situ geochemical conditions

    Science.gov (United States)

    Kumata, M.; Vandergraaf, T. T.

    1998-12-01

    Results are reported for migration experiments performed with Np under in situ geochemical conditions over a range of groundwater flow rates in columns of crushed rock in a specially designed facility at the 240-level of the Underground Research Laboratory (URL) near Pinawa, Manitoba, Canada. This laboratory is situated in an intrusive granitic rock formation, the Lac du Bonnet batholith. Highly altered granitic rock and groundwater were obtained from a major subhorizontal fracture zone at a depth of 250 m in the URL. The granite was wet-crushed and wet-sieved with groundwater from this fracture zone. The 180-850-μm size fraction was selected and packed in 20-cm long, 2.54-cm in diameter Teflon™-lined stainless steel columns. Approximately 30-ml vols of groundwater containing 3HHO and 237Np were injected into the columns at flow rates of 0.3, 1, and 3 ml/h, followed by elution with groundwater, obtained from the subhorizontal fracture, at the same flow rates, for a period of 95 days. Elution profiles for 3HHO were obtained, but no 237Np was detected in the eluted groundwater. After terminating the migration experiments, the columns were frozen, the column material was removed and cut into twenty 1-cm thick sections and each section was analyzed by gamma spectrometry. Profiles of 237Np were obtained for the three columns. A one-dimensional transport model was fitted to the 3HHO breakthrough curves to obtain flow parameters for this experiment. These flow parameters were in turn applied to the 237Np concentration profiles in the columns to produce sorption and dispersion coefficients for Np. The results show a strong dependence of retardation factors ( Rf) on flow rate. The decrease in the retarded velocity of the neptunium ( Vn) varied over one order of magnitude under the geochemical conditions for these experiments.

  2. Experimental thermochemistry of neptunium oxides: Np2O5 and NpO2

    Science.gov (United States)

    Zhang, Lei; Dzik, Ewa A.; Sigmon, Ginger E.; Szymanowski, Jennifer E. S.; Navrotsky, Alexandra; Burns, Peter C.

    2018-04-01

    Neptunium (Np) compounds are important in the nuclear fuel cycle because of the buildup and long half-life (2.14 Ma) of Np-237 in nuclear waste, especially during long-term disposal in a geological repository. Neptunium in environmental conditions exists mainly in two oxidation states (+5 and + 4) and can substitute for uranium and/or rare earths in solid phases. Yet thermochemical data for solid neptunium compounds are scarce, despite being critical for evaluating the environmental transport of this radioactive and toxic element. Although high temperature oxide melt solution calorimetry has proven very useful in obtaining thermodynamic data for the formation of uranium and thorium oxide materials, it has not yet been applied to transuranium compounds. Continuing a program at Notre Dame to study the thermodynamics of transuranium compounds, we report the first determination of the enthalpies of drop solution of well-characterized neptunium oxides (Np2O5 and NpO2) using oxide melt solution calorimetry in molten sodium molybdate solvent at 973 K. The enthalpy of the decomposition reaction, Np2O5(cr) = 2NpO2(cr) + 1/2O2(g) at 298 K, is determined to be 7.70 ± 5.86 kJ/mol, and this direct measurement is consistent with existing thermodynamic data. The calorimetric methodology is straightforward and produces reliable data using milligram quantities of radioactive materials, and can be applied to many other transuranium compounds.

  3. Gastrointestinal absorption of neptunium in primates: effect of ingested mass, diet, and fasting

    International Nuclear Information System (INIS)

    Metivier, H.; Bourges, J.; Fritsch, P.; Nolibe, D.; Masse, R.

    1986-01-01

    Absorption and retention of neptunium were determined in baboons after intragastric administration of neptunium nitrate solutions at pH 1. The effects of mass, diet, and fasting on absorption were studied. At higher mass levels (400-800 micrograms Np/kg), absorption was about 1%; at lower mass intakes (0.0009-0.005 micrograms Np/kg), absorption was reduced by 10- to 20-fold. The addition of an oxidizing agent (Fe3+) increased gastrointestinal absorption and supported the hypothesis of a reduction of Np (V) when loss masses were ingested. Diets depleted of or enriched with hydroxy acids did not modify retention of neptunium but increased urinary excretion with increasing hydroxy acid content. The diet enriched with milk components reduced absorption by a factor of 5. Potatoes increased absorption and retention by a factor 5, not necessarily due to the effect of phytate. Fasting for 12 or 24 h increased retention and absorption by factors of about 3 and 10, respectively. Data obtained in baboons when low masses of neptunium were administered suggest that the f1 factor used by ICRP should be decreased. However, fasting as encountered in certain nutritional habits is a factor to be taken into consideration

  4. Gastrointestinal absorption and retention of neptunium by fasted and fed mice

    International Nuclear Information System (INIS)

    Larsen, R.P.; Bhattacharyya, M.H.; Oldham, R.D.; Moretti, E.S.

    1982-01-01

    The retention of neptunium in liver and bone subsequent to its gastrointestinal absorption has been determined in both fasted and fed mice. The values obtained for fractional retention were 3 x 10 - 3 and 1 x 10 - 4 , respectively, and are within a factor of two the same as those for plutonium in fasted and fed mice

  5. Neptunium sorption and co-precipitation of strontium in simulated DWPF salt solution

    International Nuclear Information System (INIS)

    McIntyre, P.F.; Orebaugh, E.G.; King, C.M.

    1988-01-01

    Batch experiments performed using crushed slag saltstone (∼40 mesh) removed >80% of 237 Np from simulated Defense Waste Processing Facility (DWPF) salt solution. The concentration of 237 Np (110 pCi/ml) used was 1000x greater than levels in actual DWPF solutions. Neptunium-239 was used as a tracer and was formed by neutron activation of uranyl nitrate. Results showed that small amounts of crushed saltstone (as little as 0.05 grams), removed >80% of neptunium from 15 ml of simulated DWPF solution after several hours equilibration. The neptunium is sorbed on insoluble carbonates formed in and on the saltstone matrix. Further testing showed that addition of 0.01 and 0.10 ml of 1 molar Ca +2 (ie. Ca (NO 3 ) 2 , CaCl 2 ) into 15 ml of simulated DWPF solution yielded a white carbonate precipitate which also removed >80% of the neptunium after 1 hour equilibration. Further experiments were performed to determine the effectiveness of this procedure to co-precipitate strontium

  6. 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

  7. Neptunium separation in trace levels from uranium solutions by extraction chromatography

    International Nuclear Information System (INIS)

    Figols, M.E.B.

    1991-01-01

    Neptunium and uranium behavior in extraction chromatography system, aiming the separation of microquantities of neptunium from uranyl nitrate solutions is described. Tri-n-octylamina (TOA), tri-n-butylphosphate (TBP), thenoyltrifluoroacetone (TTA) as stationary phase, alumina, Voltalef-UF-300, silica as support material were verified. The impregnation conditions as well as the best stationary phase/support material ratio were established. TBP/alumina, TBP/Voltalef and TOA/alumina system were selected to uranium and neptunium separation studies. In the system using TBP as extractant agent uranium and neptunium separation was reached by selective elution after the retention of both elements on the column. U-Np separation by selective retention of Np was possible with TOA system. The capacity of the column was the 66.6 mg U/mL and 191.6mg U/mL for the TBP/alumina and TBP/Voltalef systems, respectively. An application of extraction chromatography system in the final phase of irradiated uranium treatment process is proposed. (author)

  8. The complex reaction kinetics of neptunium including redox and extraction process in 30% TBP-nitric acid system

    International Nuclear Information System (INIS)

    Hu Zhang; Zhan-yuan Liu; Xian-ming Zhou; Li Li

    2017-01-01

    In order to understand the complex and dynamic neptunium process chemistry in the TBP-HNO_3 system, the kinetics involved reversible redox reaction and extraction mass transfer was investigated. The results indicates that the mass transfer rate of Np(VI) is much faster than the redox reaction in aqueous solution. The concentrations of nitric acid and nitrous acid not only can change the Np(V) oxidation reaction and Np(VI) reduction reaction rate, but also can ultimately determine the distribution of neptunium extraction equilibrium. The variety of temperature can only influence the extraction equilibrium time, but cannot alter the equilibrium state of neptunium. (author)

  9. An experimental study on the effect of ad placement, product involvement and motives on Facebook ad avoidance

    OpenAIRE

    Broeck, Van den, Evert; Poels, Karolien; Walrave, Michel

    2018-01-01

    Abstract: Facebook users do not visit the social networking site to see advertising. They are either just surfing the platform or searching for information. Therefore, advertising content is vulnerable to ad avoidance. In this study, the effect of two Facebook ad placements, sidebar ads and message stream ads, on ad avoidance intention was investigated through an online experiment. Sidebar placements are put next to the content stream, while message stream advertising is interwoven with the o...

  10. Magnetic and electronic properties of Neptunium chalcogenides from GGA + U + SOC and DFT investigations

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Wilayat [New Technologies – Research Center, University of West Bohemia, Univerzitni 8, 306 14 Pilsen (Czech Republic); Goumri-Said, Souraya, E-mail: sosaid@alfaisal.edu [College of Science, Physics Department, Alfaisal University, Riyadh 11533 (Saudi Arabia)

    2017-06-15

    Highlights: • Electronic and magnetic properties of Neptunium chalcogenides were explored theoretically using DFT approach. • Spin orbit coupling and GGA + U approach described successfully the f–f coupling. • Np{sub 2}X{sub 5} ate metallic with high magnetic character due to the Neptunium. • Fermi surfaces of Np{sub 2}Te{sub 5} have shown a greater electrical conductivity compared to Np{sub 2}Se{sub 5} and Np{sub 2}S{sub 5}. - Abstract: First-principles calculations techniques were employed to explore the structural, electronic and magnetic properties of Neptunium chalcogenides (Np{sub 2}X{sub 5}, X = S, Se and Te). No experimental or theoretical studies of their physical properties have been previously reported in the literature. The presence of highly localized f states has requested the employment of the spin orbit coupling and GGA + U approach in order to describe correctly the f–f coupling. Np{sub 2}X{sub 5} was found metallic with high magnetic character due to the Neptunium presence. Fermi surfaces of Np{sub 2}Te{sub 5} have shown a greater electrical conductivity compared to Np{sub 2}Se{sub 5} and Np{sub 2}S{sub 5}. The magnetic moment was found to be between 13.24 and 13.92μ{sub B}, principally induced by Np f and d-orbitals as well as the spin-polarization of the chalcogenes (Te, Se, S) induced by Np. Neptunium chalcogenides have shown interesting magnetic properties and should be manipulated with precaution due to their radioactive properties.

  11. Atlas of Atomic Spectral Lines of Neptunium Emitted by Inductively Coupled Plasma

    Energy Technology Data Exchange (ETDEWEB)

    DeKalb, E.L. and Edelson, M. C.

    1987-08-01

    Optical emission spectra from high-purity Np-237 were generated with a glovebox-enclosed inductively coupled plasma (ICP) source. Spectra covering the 230-700 nm wavelength range are presented along with general commentary on the methodology used in collecting the data. The Ames Laboratory Nuclear Safeguards and Security Program has been charged with the task of developing optical spectroscopic methods to analyze the composition of spent nuclear fuels. Such materials are highly radioactive even after prolonged 'cooling' and are chemically complex. Neptunium (Np) is a highly toxic by-product of nuclear power generation and is found, in low abundance, in spent nuclear fuels. This atlas of the optical emission spectrum of Np, as produced by an inductively coupled plasma (ICP) spectroscopic source, is part of a general survey of the ICP emission spectra of the actinide elements. The ICP emission spectrum of the actinides originates almost exclusively from the electronic relaxation of excited, singly ionized species. Spectral data on the Np ion emission spectrum (i.e., the Np II spectrum) have been reported by Tomkins and Fred [1] and Haaland [2]. Tomkins and Fred excited the Np II spectrum with a Cu spark discharge and identified 114 Np lines in the 265.5 - 436.3 nm spectral range. Haaland, who corrected some spectral line misidentifications in the work of Tomkins and Fred, utilized an enclosed Au spark discharge to excite the Np II spectrum and reported 203 Np lines within the 265.4 - 461.0 nm wavelength range.

  12. Atlas of Atomic Spectral Lines of Neptunium Emitted by an Inductively Coupled Plasma

    International Nuclear Information System (INIS)

    DeKalb, E.L.; Edelson, M.C.

    1987-01-01

    Optical emission spectra from high-purity Np-237 were generated with a glovebox-enclosed inductively coupled plasma (ICP) source. Spectra covering the 230-700 nm wavelength range are presented along with general commentary on the methodology used in collecting the data. The Ames Laboratory Nuclear Safeguards and Security Program has been charged with the task of developing optical spectroscopic methods to analyze the composition of spent nuclear fuels. Such materials are highly radioactive even after prolonged 'cooling' and are chemically complex. Neptunium (Np) is a highly toxic by-product of nuclear power generation and is found, in low abundance, in spent nuclear fuels. This atlas of the optical emission spectrum of Np, as produced by an inductively coupled plasma (ICP) spectroscopic source, is part of a general survey of the ICP emission spectra of the actinide elements. The ICP emission spectrum of the actinides originates almost exclusively from the electronic relaxation of excited, singly ionized species. Spectral data on the Np ion emission spectrum (i.e., the Np II spectrum) have been reported by Tomkins and Fred (1) and Haaland (2). Tomkins and Fred excited the Np II spectrum with a Cu spark discharge and identified 114 Np lines in the 265.5 - 436.3 nm spectral range. Haaland, who corrected some spectral line misidentifications in the work of Tomkins and Fred, utilized an enclosed Au spark discharge to excite the Np II spectrum and reported 203 Np lines within the 265.4 - 461.0 nm wavelength range.

  13. Combining empirical and theory-based land-use modelling approaches to assess economic potential of biofuel production avoiding iLUC: Argentina as a case study

    NARCIS (Netherlands)

    Diogo, V.; van der Hilst, F.; van Eijck, J.; Verstegen, J.A.; Hilbert, J.; Carballo, S.; Volante, J.; Faaij, A.

    2014-01-01

    In this paper, a land-use modelling framework is presented combining empirical and theory-based modelling approaches to determine economic potential of biofuel production avoiding indirect land-use changes (iLUC) resulting from land competition with other functions. The empirical approach explores

  14. A study of specific sorption of neptunium(V) on smectite in low pH solution

    International Nuclear Information System (INIS)

    Kozai, Naofumi; Ohnuki, Toshihiko; Matsumoto, Junko; Banba, Tsunetaka; Ito, Yoshimoto

    1996-01-01

    The 'specific sorption' of neptunium(V) on smectite, in other words, a strong sorption undesorbable by 1 M KCl, is studied with a combination of batch type sorption and desorption experiments over a pH range of 2 to 5. Six types of homoionic smectite (Li-, Na-, K-, Cs-, Mg-, and Ca-smectite) are used in this study. Distribution coefficients (K d ) of neptunium for smectite vary over a wide pH range; the maximum K d value of ∝300 cm 3 x g -1 at around pH 2 for Li- and Na-smectite and the minimum value of ∝2 cm 3 x g -1 for Cs-smectite. The specific sorption of neptunium depends on pH and on the affinity of the exchangeable cation for smectite; the lower the pH of solution or the affinity, the larger the specific sorption. The neptunium-smectite association varies with the elapse of contact time. Within the first day of the neptunium-smectite contact the neptunium sorbed on na-smectite at low pH is desorbable by 1 M KCl solution, and on the passage of time most of the neuptunium sorbed becomes undesorbable by KCl (the specific sorption). Hydronium ion in solution is sorbed on smectite at low pH and dissociates the exchangeable cation from smectite into solution, and the specific sorption of neuptunium increases with increasing the exchangeable cation that is dissociated from smectite. (orig.)

  15. Spectrophotometric study of neptunium (VI) complexation by nitrate ions; Etude par spectrophotometrie de la complexation du neptunium au degre d'oxydation (VI) par les ions nitrates

    Energy Technology Data Exchange (ETDEWEB)

    Pochon, P. [CEA/VALRHO - site de Marcoule, Dept. de Recherche en Retraitement et en Vitrification (DRRV), 30 - Marcoule (France)]|[Conservatoire National des Arts et Metiers (CNAM), 75 - Paris (France)]|[Centre Regional Associe de Lyon, 69 (France)

    2000-07-01

    Neptunium(VI) complexation by nitrate ions was investigated by visible and near-infrared spectrophotometry, a technique suitable for observing the appearance and evolution of the species in solution. In the absence of reference spectra for Np(VI) nitrate- complexes, mathematical (factor analysis) tools were used to interpret the spectra. These chemo-metric techniques were first tested and validated on a simpler chemical system: Np(VI)complexation by the SiW{sub 11}O{sub 39}{sup 8-} anion. The test media used to investigate Np(VI) nitrate- complexes generally contain nitrate and perchlorate salts at high concentrations (high ionic strength). Media effects arising from the presence of cations, acidity or the perchlorate ion concentration are therefore significant, and no doubt account for the scattered values of the complexation constants published in the literature. The evolution of the neptunium spectra according to the parameters of the reaction medium illustrated these effects and allowed them to be quantified by a global 'perturbation constant'. In order to minimize the spectrum modifications due to media effects, the neptunium nitrate-complexes were studied at constant ionic strength in weak acidic media (2 mol.kg{sup -1}{sub H2O}) in the presence of sodium salts. The bulk formation constants and the spectrum of the NpO{sub 2}(NO{sub 3}){sup +} complex were determined for ionic strength values of 2.2, 4, 6 and 8 mol.kg{sup -1}{sub H2O}. The constants remained on the same order of magnitude regardless of the ionic strength; the thermodynamic constant {beta}{sub 1}{sup 0} determined from them according to specific interaction theory is thus probably of little significance. Conversely, the bulk constants can be corrected for the effects of the perchlorate ions by taking the global 'perturbation constant' into account. (author)

  16. Chemical speciation of neptunium in spent fuel. Annual report for period 15 August 1999 to 15 August 2000

    Energy Technology Data Exchange (ETDEWEB)

    Ken Czerwinski; Don Reed

    2000-09-01

    (B204) This project will examine the chemical speciation of neptunium in spent nuclear fuel. The R&D fields covered by the project include waste host materials and actinide chemistry. Examination of neptunium is chosen since it was identified as a radionuclide of concern by the NERI workshop. Additionally, information on the chemical form of neptunium in spent fuel is lacking. The identification of the neptunium species in spent fuel would allow a greater scientific based understanding of its long-term fate and behavior in waste forms. Research to establish the application and development of X-ray synchrotrons radiation (XSR) techniques to determine the structure of aqueous, adsorbed, and solid actinide species of importance to nuclear considerations is being conducted at Argonne. These studies extend current efforts within the Chemical Technology Division at Argonne National Laboratory to investigate actinide speciation with more conventional spectroscopic and solids characterization (e.g. SEM, TEM, and XRD) methods. Our project will utilize all these techniques for determining neptunium speciation in spent fuel. We intend to determine the chemical species and oxidation state of neptunium in spent fuel and alteration phases. Different types of spent fuel will be examined. Once characterized, the chemical behavior of the identified neptunium species will be evaluated if it is not present in the literature. Special attention will be given to the behavior of the neptunium species under typical repository near-field conditions (elevated temperature, high pH, varying Eh). This will permit a timely inclusion of project results into near-field geochemical models. Additionally, project results and methodologies have applications to neptunium in the environment, or treatment of neptunium containing waste. Another important aspect of this project is the close cooperation between a university and a national laboratory. The PI has a transuranic laboratory at MIT where

  17. Chemical speciation of neptunium in spent fuel. Annual report for period 15 August 1999 to 15 August 2000

    International Nuclear Information System (INIS)

    Ken Czerwinski; Don Reed

    2000-01-01

    (B204) This project will examine the chemical speciation of neptunium in spent nuclear fuel. The R and D fields covered by the project include waste host materials and actinide chemistry. Examination of neptunium is chosen since it was identified as a radionuclide of concern by the NERI workshop. Additionally, information on the chemical form of neptunium in spent fuel is lacking. The identification of the neptunium species in spent fuel would allow a greater scientific based understanding of its long-term fate and behavior in waste forms. Research to establish the application and development of X-ray synchrotrons radiation (XSR) techniques to determine the structure of aqueous, adsorbed, and solid actinide species of importance to nuclear considerations is being conducted at Argonne. These studies extend current efforts within the Chemical Technology Division at Argonne National Laboratory to investigate actinide speciation with more conventional spectroscopic and solids characterization (e.g. SEM, TEM, and XRD) methods. Our project will utilize all these techniques for determining neptunium speciation in spent fuel. We intend to determine the chemical species and oxidation state of neptunium in spent fuel and alteration phases. Different types of spent fuel will be examined. Once characterized, the chemical behavior of the identified neptunium species will be evaluated if it is not present in the literature. Special attention will be given to the behavior of the neptunium species under typical repository near-field conditions (elevated temperature, high pH, varying Eh). This will permit a timely inclusion of project results into near-field geochemical models. Additionally, project results and methodologies have applications to neptunium in the environment, or treatment of neptunium containing waste. Another important aspect of this project is the close cooperation between a university and a national laboratory. The PI has a transuranic laboratory at MIT where

  18. Stability constants and solubility of neptunium and plutonium complexes with alkylphosphoric acids in TBP

    International Nuclear Information System (INIS)

    Fedoseev, D.A.; Romanovskaya, I.A.; Artemova, L.A.; Gubina, M.Yu.

    1988-01-01

    Stability concetration constants K and solubility of neptunium and plutonium complexes with di- and monobuthylphosphoric acids (APC) and with orthophosphoric and di-2-ethylhexyl-phosphoric acids in 30% TBP solution-n-dodecane system are determined by spectrophotometric titration and radiometry methods. Posibility of forecasting radiation-chemical behaviour of actinids according to data on K and APC radiation-chemical yield values is demonstrated

  19. Appraisal of available information on uptake by plants of transplutonium elements and neptunium

    International Nuclear Information System (INIS)

    Thomas, R.L.; Healy, J.W.

    1976-07-01

    A critical review was made of reported information from laboratory studies of plant uptake of transplutonic elements plus neptunium. The available data are meager but indicate that the uptake of Np is the greatest followed by Am and Cm. The data are not sufficient to provide recommended values for use in hazard calculations but they do indicate that the actinides other than plutonium will be accumulated in plants to a greater degree than plutonium

  20. Stability constants and solubility of neptunium and plutonium complexes with alkylphosphoric acids in TBP

    International Nuclear Information System (INIS)

    Fedoseev, D.A.; Romanovskaya, I.A.; Artemova, L.A.; Gibina, M.Yu.

    1989-01-01

    The concentration stability constants (K s ) and solubility of neptunium and plutonium complexes with di- and monobutylphosphoric acids (APA), as well as with orthophosphoric acid in the system composed of 30% TBP + n-dodecane, have been determined by spectrophotometric titration and radiometry. The feasibility of predicting the radiative chemical behavior of actinides based on their K s values and the radiative chemical yield of APA has been demonstrated

  1. New Synthetic Methods and Structure-Property Relationships in Neptunium, Plutonium, and Americium Borates. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Albrecht-Schmitt, Thomas Edward

    2013-09-14

    The past three years of support by the Heavy Elements Chemistry Program have been highly productive in terms of advanced degrees awarded, currently supported graduate students, peer-reviewed publications, and presentations made at universities, national laboratories, and at international conferences. Ph.D. degrees were granted to Shuao Wang and Juan Diwu, who both went on to post-doctoral appointments at the Glenn T. Seaborg Center at Lawrence Berkeley National Laboratory with Jeff Long and Ken Raymond, respectively. Pius Adelani completed his Ph.D. with me and is now a post-doc with Peter C. Burns. Andrea Alsobrook finished her Ph.D. and is now a post-doc at Savannah River with Dave Hobbs. Anna Nelson completed her Ph.D. and is now a post-doc with Rod Ewing at the University of Michigan. As can be gleaned from this list, students supported by the Heavy Elements Chemistry grant have remained interested in actinide science after leaving my program. This follows in line with previous graduates in this program such as Richard E. Sykora, who did his post-doctoral work at Oak Ridge National Laboratory with R. G. Haire, and Amanda C. Bean, who is a staff scientist at Los Alamos National Laboratory, and Philip M. Almond and Thomas C. Shehee, who are both staff scientists at Savannah River National Laboratory, Gengbang Jin who is a staff scientist at Argonne National Lab, and Travis Bray who has been a post-doc at both LBNL and ANL. Clearly this program is serving as a pipe-line for students to enter into careers in the national laboratories. About half of my students depart the DOE complex for academia or industry. My undergraduate researchers also remain active in actinide chemistry after leaving my group. Dan Wells was a productive undergraduate of mine, and went on to pursue a Ph.D. on uranium and neptunium chalcogenides with Jim Ibers at Northwestern. After earning his Ph.D., he went directly into the nuclear industry.

  2. New Synthetic Methods and Structure-Property Relationships in Neptunium, Plutonium, and Americium Borates. Final report

    International Nuclear Information System (INIS)

    Albrecht-Schmitt, Thomas Edward

    2013-01-01

    The past three years of support by the Heavy Elements Chemistry Program have been highly productive in terms of advanced degrees awarded, currently supported graduate students, peer-reviewed publications, and presentations made at universities, national laboratories, and at international conferences. Ph.D. degrees were granted to Shuao Wang and Juan Diwu, who both went on to post-doctoral appointments at the Glenn T. Seaborg Center at Lawrence Berkeley National Laboratory with Jeff Long and Ken Raymond, respectively. Pius Adelani completed his Ph.D. with me and is now a post-doc with Peter C. Burns. Andrea Alsobrook finished her Ph.D. and is now a post-doc at Savannah River with Dave Hobbs. Anna Nelson completed her Ph.D. and is now a post-doc with Rod Ewing at the University of Michigan. As can be gleaned from this list, students supported by the Heavy Elements Chemistry grant have remained interested in actinide science after leaving my program. This follows in line with previous graduates in this program such as Richard E. Sykora, who did his post-doctoral work at Oak Ridge National Laboratory with R. G. Haire, and Amanda C. Bean, who is a staff scientist at Los Alamos National Laboratory, and Philip M. Almond and Thomas C. Shehee, who are both staff scientists at Savannah River National Laboratory, Gengbang Jin who is a staff scientist at Argonne National Lab, and Travis Bray who has been a post-doc at both LBNL and ANL. Clearly this program is serving as a pipe-line for students to enter into careers in the national laboratories. About half of my students depart the DOE complex for academia or industry. My undergraduate researchers also remain active in actinide chemistry after leaving my group. Dan Wells was a productive undergraduate of mine, and went on to pursue a Ph.D. on uranium and neptunium chalcogenides with Jim Ibers at Northwestern. After earning his Ph.D., he went directly into the nuclear industry

  3. Stabilization of neptunium valence states in nitric media for spent nuclear fuel reprocessing

    International Nuclear Information System (INIS)

    Feldhaus, P.

    1996-12-01

    A possibility of standarizing the extraction-behavior of Neptunium during the reprocessing of spent nuclear fuel corresponding to PUREX-Process was investigated. The aim of the work was a qualitative dirigation of the Transuraniumelement (TRUE) into the raffinat of the first extraction cycle by a complete redoxconversion of the Neptunium valence states to unextractable Np(V). In the beginning the theoretical and experimental research focussed on the redoxchemistry of the actinide during the fuel dissolution and the feed preparation. Thereby the nitrous acid, which is produced by a radiological, photochemical and reductive degradation of the nitric acid, revealed an ambivalent influence on the Neptunium valences. By a short-term increase in HNO 2 -concentration the Np(V)-fraction could be obviously risen. The use of some stabilizing reagents inhibited a later reoxidation to Np(VI) also catalyzed by nitrous acid. The urea used for this purpose also led to a further increase in the obtained conversion rates due to a Np(VI)-reduction. The analysis of the valence distribution was performed by an extraction method. This had been compared to chromatographic separation in some preliminary investigations and had turned out to be comparably reliable and easily manageable. (orig.) [de

  4. Development of analytical methods for the separation of plutonium, americium, curium and neptunium from environmental samples

    Energy Technology Data Exchange (ETDEWEB)

    Salminen, S.

    2009-07-01

    In this work, separation methods have been developed for the analysis of anthropogenic transuranium elements plutonium, americium, curium and neptunium from environmental samples contaminated by global nuclear weapons testing and the Chernobyl accident. The analytical methods utilized in this study are based on extraction chromatography. Highly varying atmospheric plutonium isotope concentrations and activity ratios were found at both Kurchatov (Kazakhstan), near the former Semipalatinsk test site, and Sodankylae (Finland). The origin of plutonium is almost impossible to identify at Kurchatov, since hundreds of nuclear tests were performed at the Semipalatinsk test site. In Sodankylae, plutonium in the surface air originated from nuclear weapons testing, conducted mostly by USSR and USA before the sampling year 1963. The variation in americium, curium and neptunium concentrations was great as well in peat samples collected in southern and central Finland in 1986 immediately after the Chernobyl accident. The main source of transuranium contamination in peats was from global nuclear test fallout, although there are wide regional differences in the fraction of Chernobyl-originated activity (of the total activity) for americium, curium and neptunium. The separation methods developed in this study yielded good chemical recovery for the elements investigated and adequately pure fractions for radiometric activity determination. The extraction chromatographic methods were faster compared to older methods based on ion exchange chromatography. In addition, extraction chromatography is a more environmentally friendly separation method than ion exchange, because less acidic waste solutions are produced during the analytical procedures. (orig.)

  5. Action of copper (3) in periodate complex on hexavalent neptunium and plutonium in alkaline medium

    International Nuclear Information System (INIS)

    Shatokhina, O.B.; Alekseeva, D.P.; Peretrukhin, B.F.; Krot, N.N.

    1977-01-01

    A complex of trivalent copper connected with periodate has been studied in order to determine its possible use for oxidizing hexavalent transuranium elements. Proceeding from the dependence of formal potentials of the pairs Cusup((3))-Cusup((2)), Npsup((7))-Npsup((6)), Pusup((7))-Pusup((6)) on alkali concentration, it has been established that beginning with concentration 1M the potential of the pair Cusup((3))-Cusup((2)) is higher than that of the pair Npsup((7))-Npsup((6)) by approximately 50 mV. This means that a rather complete oxidation of hexavalent neptunium to heptavalent is possible by the action of copper (3) excess on neptunium (6) when KOH concentration is 1M and higher. Oxidation close to quantitative is attained in 1M KOH when excess of copper(3) is used and the ratio Npsup((6)): Cusup((3)) is 1:4 and higher. When KOH concentration is more than 1M a sufficiently complete oxidation (96-97%) of neptunium (6) is attained at Npsup((6)):Cusup((3))=1:2 or 1:3. Optimum conditions for oxidizing plutonium are 11M KOH and 2-3-fold excess of copper (3) reagent. At 9M KOH and a ratio Pusup((6)):Cusup((3))=1:2 the yield of Pu (7) is 33 %

  6. Study on reduction reactions of neptunium(V) on magnetite surface

    International Nuclear Information System (INIS)

    Kitamura, Akira; Kamei, Gento; Nakata, Kotaro; Tanaka, Satoru; Tomura, Tsutomu

    2004-01-01

    Redox reactions between neptunium(V) (Np(V)) and magnetite (Fe(II) 1 Fe(III) 2 O 4 ) surface were investigated in N 2 gas atmosphere. A batch method was applied to the experiment. A magnetite sample and a 0.1 M NaCl solution were mixed in a polypropylene tube, and pH, redox potential and concentration of dissolved neptunium were measured as a function of shaking time, temperature and liquid/solid ratio. The concentration of dissolved neptunium was reduced rapidly within a day, due to the reducing reaction of Np(V) to Np(IV) and the precipitation of Np(IV). The rate constant of the redox reaction and the activation energy for the rate constant were preliminarily obtained. On the other hand, redox reactions between Np(V) and aqueous Fe(II) were hardly observed. Considering the number of transferred electrons, it was suggested that the redox reaction was promoted by not only Fe(II) on the magnetite surface, but also Fe(II) inside the magnetite. (author)

  7. Influence of dissolved organic substances in groundwater on sorption behavior of americium and neptunium

    International Nuclear Information System (INIS)

    Boggs, S. Jr.; Seitz, M.G.

    1984-01-01

    Groundwaters typically contain dissolved organic carbon consisting largely of high molecular weight compounds of humic and fulvic acids. To evaluate whether these dissolved organic substances can enhance the tranport of radionuclides through the groundwater system, experiments were conducted to examine the sorption of americium and neptunium onto crushed basalt in the presence of dissolved humic- and fulvic-acid organic carbon introduced into synthetic groundwater. The partitioning experiments with synthetic groundwater show that increasing the concentration of either humic or fulvic acid in the water has a significant inhibiting effect on sorption of both americium and neptunium. At 22 0 C, adsorption of these radionuclides, as measured by distribution ratios (the ratio of nuclide sorbed onto the solid to nuclide in solution at the end of the experiment), decreased by 25% to 50% by addition of as little as 1 mg/L dissolved organic carbon and by one to two orders of magnitude by addition of 100 to 200 mg/L dissolved organic carbon. Distribution ratios measured in solutions reacted at 90 0 C similarly decreased with the addition of dissolved organic carbon but generally ranged from one to two orders of magnitude higher than those determined in the 22 0 C experiment. These results suggest that organic carbon dissolved in deep groundwaters may significantly enhance the mobility of radionuclides of americium and neptunium. 23 references, 5 figures, 11 tables

  8. Years of Life and Productivity Loss from Potentially Avoidable Colorectal Cancer Deaths in U.S. Counties with Lower Educational Attainment (2008-2012).

    Science.gov (United States)

    Weir, Hannah K; Li, Chunyu; Henley, S Jane; Joseph, Djenaba

    2017-05-01

    Background: Educational attainment (EA) is inversely associated with colorectal cancer risk. Colorectal cancer screening can save lives if precancerous polyps or early cancers are found and successfully treated. This study aims to estimate the potential productivity loss (PPL) and associated avoidable colorectal cancer-related deaths among screen-eligible adults residing in lower EA counties in the United States. Methods: Mortality and population data were used to examine colorectal cancer deaths (2008-2012) among adults aged 50 to 74 years in lower EA counties, and to estimate the expected number of deaths using the mortality experience from high EA counties. Excess deaths (observed-expected) were used to estimate potential years life lost, and the human capital method was used to estimate PPL in 2012 U.S. dollars. Results: County-level colorectal cancer death rates were inversely associated with county-level EA. Of the 100,857 colorectal cancer deaths in lower EA counties, we estimated that more than 21,000 (1 in 5) was potentially avoidable and resulted in nearly $2 billion annual productivity loss. Conclusions: County-level EA disparities contribute to a large number of potentially avoidable colorectal cancer-related deaths. Increased prevention and improved screening potentially could decrease deaths and help reduce the associated economic burden in lower EA communities. Increased screening could further reduce deaths in all EA groups. Impact: These results estimate the large economic impact of potentially avoidable colorectal cancer-related deaths in economically disadvantaged communities, as measured by lower EA. Cancer Epidemiol Biomarkers Prev; 26(5); 736-42. ©2016 AACR . ©2016 American Association for Cancer Research.

  9. Years of Life and Productivity Loss from Potentially Avoidable Colorectal Cancer Deaths in U.S. Counties with Lower Educational Attainment (2008–2012)

    Science.gov (United States)

    Weir, Hannah K.; Li, Chunyu; Henley, S. Jane; Joseph, Djenaba

    2018-01-01

    Background Educational attainment (EA) is inversely associated with colorectal cancer risk. Colorectal cancer screening can save lives if precancerous polyps or early cancers are found and successfully treated. This study aims to estimate the potential productivity loss (PPL) and associated avoidable colorectal cancer–related deaths among screen-eligible adults residing in lower EA counties in the United States. Methods Mortality and population data were used to examine colorectal cancer deaths (2008–2012) among adults aged 50 to 74 years in lower EA counties, and to estimate the expected number of deaths using the mortality experience from high EA counties. Excess deaths (observed–expected) were used to estimate potential years life lost, and the human capital method was used to estimate PPL in 2012 U.S. dollars. Results County-level colorectal cancer death rates were inversely associated with county-level EA. Of the 100,857 colorectal cancer deaths in lower EA counties, we estimated that more than 21,000 (1 in 5) was potentially avoidable and resulted in nearly $2 billion annual productivity loss. Conclusions County-level EA disparities contribute to a large number of potentially avoidable colorectal cancer–related deaths. Increased prevention and improved screening potentially could decrease deaths and help reduce the associated economic burden in lower EA communities. Increased screening could further reduce deaths in all EA groups. Impact These results estimate the large economic impact of potentially avoidable colorectal cancer–related deaths in economically disadvantaged communities, as measured by lower EA. PMID:28003180

  10. Use of radioanalytical methods for determination of uranium, neptunium, plutonium, americium and curium isotopes in radioactive wastes

    International Nuclear Information System (INIS)

    Geraldo, Bianca

    2012-01-01

    Activated charcoal is a common type of radioactive waste that contains high concentrations of fission and activation products. The management of this waste includes its characterization aiming the determination and quantification of the specific radionuclides including those known as Difficult-to-Measure Radionuclides (RDM). The analysis of the RDM's generally involves complex radiochemical analysis for purification and separation of the radionuclides, which are expensive and time-consuming. The objective of this work was to define a methodology for sequential analysis of the isotopes of uranium, neptunium, plutonium, americium and curium present in a type of radioactive waste, evaluating chemical yield, analysis of time spent, amount of secondary waste generated and cost. Three methodologies were compared and validated that employ ion exchange (TI + EC), extraction chromatography (EC) and extraction with polymers (ECP). The waste chosen was the activated charcoal from the purification system of primary circuit water cooling the reactor IEA-R1. The charcoal samples were dissolved by acid digestion followed by purification and separation of isotopes with ion exchange resins, extraction and chromatographic extraction polymers. Isotopes were analyzed on an alpha spectrometer, equipped with surface barrier detectors. The chemical yields were satisfactory for the methods TI + EC and EC. ECP method was comparable with those methods only for uranium. Statistical analysis as well the analysis of time spent, amount of secondary waste generated and cost revealed that EC method is the most effective for identifying and quantifying U, Np, Pu, Am and Cm present in charcoal. (author)

  11. How can we avoid the lock-in problem in the substitution of hazardous chemicals used in consumer products?

    DEFF Research Database (Denmark)

    Scheringer, Martin; Fantke, Peter; Weber, R.

    2014-01-01

    A wide range of chemical substances is used in consumer products for various purposes, including plastic softeners, dyestuffs and colorants, flame retardants, impregnation agents, antioxidants and UV absorbers, preservation agents and biocides, and many others. Among these chemicals, there is a c......A wide range of chemical substances is used in consumer products for various purposes, including plastic softeners, dyestuffs and colorants, flame retardants, impregnation agents, antioxidants and UV absorbers, preservation agents and biocides, and many others. Among these chemicals...

  12. Silicification of wood adopted for barrel production using pure silicon alkoxides in gas phase to avoid microbial colonisation.

    Science.gov (United States)

    Guzzon, Raffaele; Widmann, Giacomo; Bertoldi, Daniela; Nardin, Tiziana; Callone, Emanuela; Nicolini, Giorgio; Larcher, Roberto

    2015-02-01

    The paper presents a new approach, covering wood with silica-based material in order to protect it from spoilage due to microbial colonisation and avoiding the loss of the natural features of the wood. Wood specimens derived from wine barrels were treated with methyltriethoxysilane in gas phase, leading to the deposition of a silica nanofilm on the surface. (29)Si and (13)C solid state Nuclear Magnetic Resonance and Scanning Electron Microscope-Energy Dispersive X-ray analysis observations showed the formation of a silica polymeric film on the wood samples, directly bonding with the wood constituents. Inductively Coupled Plasma-Mass Spectroscopy quantification of Si showed a direct correlation between the treatment time and silica deposition on the surface of the wood. The silica-coated wood counteracted colonisation by the main wine spoilage microorganisms, without altering the migration from wood to wine of 21 simple phenols measured using a HPLC-Electrochemical Coulometric Detection. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Investigations into the sorption of neptunium by loose rock from the cap rock of the Gorleben salt dome under aerobic and anaerobic conditions

    International Nuclear Information System (INIS)

    Muehlenweg, U.

    1988-01-01

    In the experiments with the natural loose rock the sorption behaviour of neptunium was essentially determined by the chemical form in which the neptunium occurred in the ground waters. Under aerobic conditions with Eh values of 300 mV, neptunium in its oxidation state +5 occurred. At a pH of 2 + , and at pH > 8 as carbonato complex. The found neptunium species were relatively mobile, with sorption values from 1 ml/g to 20 ml/g. The sorption of neptunium is comparable to that of alkali and alkaline earth ions, such as Cs + or Sr 2+ . Cations attached to the rock surface are exchanged for NpO 2 + . Sorption in this case is reversible. (orig.) [de

  14. Simulation study of the chemical forms of neptunium and plutonium in groundwater from a borehole in the northwest region

    International Nuclear Information System (INIS)

    Ma Yingming; Jin Yuren; Wang Zhiqiang; Liu Dongxu; Liu Wei; Liu Yan

    2009-01-01

    According to physics-chymistry characteristic of groundwater from a borehole in the northwest region, we performed simulation study of the chemical forms of neptunium and plutonium by the geochemistry modeling program EQ3/6. The main conclusions are as follows: the main chemical form of neptunium in the groundwater is Np(V)'s NpO 2 + , subordination chemical forms are NpO 2 Cl, NpO 2 CO 3 - , NpO 2 OH, NpO 2 SO 4 - ; the main existing form of plutonium in the groundwater is Pu(IV)'s Pu(OH)5-and subordination chemical form is Pu(V)'s PuO 2 + . In addition,the temperature, pH and Eh also have different impacts on the chemical form of neptunium and plutonium. (authors)

  15. Re-assessment of net energy production and greenhouse gas emissions avoidance after 40 years of photovoltaics development

    NARCIS (Netherlands)

    Louwen, Atse|info:eu-repo/dai/nl/375268456; Van Sark, Wilfried G J H M|info:eu-repo/dai/nl/074628526; Faaij, André P C; Schropp, Ruud E I|info:eu-repo/dai/nl/072502584

    2016-01-01

    Since the 1970s, installed solar photovoltaic capacity has grown tremendously to 230 gigawatt worldwide in 2015, with a growth rate between 1975 and 2015 of 45%. This rapid growth has led to concerns regarding the energy consumption and greenhouse gas emissions of photovoltaics production. We

  16. HF effect on dissociation kinetics of plutonium and neptunium complexes with 1,2-diaminocyclohexanetetraacetic acid in nitric acid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Nikitina, S.A.; Stepanov, A.V.

    1982-01-01

    Dissociation kinetics of Pusup((4)) and Np sup((4)) complexes with DCTA were investigated in HNO/sub 3/ solutions in the presence of HF and arsenazo 3. It was found that HF or NaF produced a differentiating effect on the reactivity of the complexes at (HNO/sub 3/)=1-6 mol/l as well as inhibiting effect at (HNO/sub 3/)=0.01 mol/l. Conditions of the differential kinetic analysis of plutonium and neptunium in the mixture and differential spectrophotometric analysis of uranium (6) during the camouflage of neptunium (4) and plutonium (4) were determined.

  17. HF effect on dissociation kinetics of plutonium and neptunium complexes with 1,2-diaminocyclohexanetetraacetic acid in nitric acid solutions

    International Nuclear Information System (INIS)

    Nikitina, S.A.; Stepanov, A.V.

    1982-01-01

    Dissociation kinetics of Pusup((4)) and Np sup((4)) complexes with DCTA were investigated in HNO 3 solutions in the presence of HF and arsenazo 3. It was found that HF or NaF produced a differentiating effect on the reactivity of the complexes at [HNO 3 ]=1-6 mol/l as well as inhibiting effect at [HNO 3 ]=0.01 mol/l. Conditions of the differential kinetic analysis of plutonium and neptunium in the mixture and differential spectrophotometric analysis of uranium (6) during the camouflage of neptunium (4) and plutonium (4) were determined

  18. Kinetics of the reaction between plutonium (4) and neptunium (4) in nitric acid solution

    Energy Technology Data Exchange (ETDEWEB)

    Koltunov, V S; Zhuravleva, G I; Marchenko, V I

    1976-01-01

    The kinetics of the oxidation of neptunium(IV) to neptunium(V) by tetravalent plutonium ions in solutions of HNO/sub 3/ + NaNO/sub 3/ at constant (..mu.. = 2) and variable (..mu.. = 0.7-2.0) ionic strengths of the solution was investigated by a spectrophotometric method. It was established that in the range of concentrations (Np(IV)) = (4.25-10.6) x 10/sup 13/; (Pu(IV)) = (2.6-3.9)x10/sup -3/ M; (H/sup +/) 0.37-1.91 M, a first order is observed with respect to the reagents, while the order of the reaction with respect to H/sup +/ ions is equal to -3. The average value of the true rate constant of the reaction is k = 27.9+-1.3 M/sup 2/xmin/sup -1/ at ..mu..=2 and 39/sup 0/C. It was shown that with increasing analytical concentration of HNO/sub 3/ and NO/sub 3//sup -/ ions (in a mixture of HNO/sub 3/ +HClO/sub 4/), the value of K decreases. On the basis of an invetigation of the dependence of the reaction rate on the temperature in the interval 31-44.8/sup 0/, we calculated the values of the energy (E = 34.6 kcal/mole), enthalpy (..delta..H* = 34 kcal/mole), free energy (..delta..F* = 19.6 kcal/mole, entropy (..delta..S* = 49 entropy units) of activation of the reaction and the formal ionic entropy of the activated complex (PuOOHNp/sup 5 +/)*, S* = -87 entropy units. A reaction mechanism including an interaction of hydrolyzed neptunium and plutonium ions as the rate-determining step was proposed and discusses. The results obtained are compared with data for this reaction in perchloric acid wolution and for other similar redox reactions.

  19. Partitioning and recovery of neptunium from high level waste streams of PUREX origin using 30% TBP

    International Nuclear Information System (INIS)

    Mathur, J.N.; Murali, M.S.; Balarama Krishna, M.V.; Iyer, R.H.; Chitnis, R.R.; Wattal, P.K.; Theyyunni, T.K.; Ramanujam, A.; Dhami, P.S.; Gopalakrishnan, V.

    1995-01-01

    237 Np is one of the longest-lived nuclides among the actinides present in the high level waste solutions of reprocessing origin. Its separation, recovery and transmutation can reduce the problem of long term storage of the vitrified waste to a great extent. With this objective, the present work was initiated to study the extraction of neptunium into TBP under the conditions relevant to high level waste, along with uranium and plutonium by oxidising it to hexavalent state using potassium dichromate and subsequently recovering it by selective stripping. Three types of simulated HLW solutions namely sulphate bearing (SB), with an acidity of ∼ 0.3 M and non-sulphate wastes originating from the reprocessing of fuels from pressurised heavy water reactor (PHWR) and fast breeder reactor (FBR) with acidities of 3.0 M HNO 3 were employed in these studies. The extraction of U(VI), Np(VI) and Pu(VI) was very high for PHWR- and FBR-HLW solutions, whereas for the SB-HLW solution, these values were less but reasonably high. Quantitative recovery of neptunium and plutonium was achieved using a stripping solution containing 0.1 M H 2 O 2 and 0.01 M ascorbic acid at an acidity of 2.0 M. Since, cerium present in the waste solutions is expected to undergo oxidation in presence of K 2 Cr 2 O 7 , its extraction behaviour was also studied under similar conditions. Based on the results, a scheme was formulated for the recovery of neptunium along with plutonium and was successfully applied to actual high level waste solution originating from the reprocessing of research reactor fuels. (author). 19 refs., 2 figs., 17 tabs

  20. Mathematical modeling of the radiation-chemical behavior of neptunium in HNO3. Equilibrium states

    International Nuclear Information System (INIS)

    Vladimirova, M.V.

    1995-01-01

    A mathematical model of the radiation-chemical behavior of neptunium is presented for a wide range of α-and γ-irradiation doses. Equations determining the equilibrium concentrations of NP(IV), Np(V), and Np(VI) are derived for various concentrations of HNO 3 and dose rates of the ionizing irradiation. The rate constants of the reactions NP(IV) + OH, Np(IV) + NO 3 , Np(V) + NO 2 , Np(V) + H, Np(IV), and Np(V) + Np(V) are obtained by the mathematical modeling

  1. Comparison of sample preparation methods for reliable plutonium and neptunium urinalysis using automatic extraction chromatography

    DEFF Research Database (Denmark)

    Qiao, Jixin; Xu, Yihong; Hou, Xiaolin

    2014-01-01

    This paper describes improvement and comparison of analytical methods for simultaneous determination of trace-level plutonium and neptunium in urine samples by inductively coupled plasma mass spectrometry (ICP-MS). Four sample pre-concentration techniques, including calcium phosphate, iron......), it endows urinalysis methods with better reliability and repeatability compared with co-precipitation techniques. In view of the applicability of different pre-concentration techniques proposed previously in the literature, the main challenge behind relevant method development is pointed to be the release...

  2. Source-driven noise analysis measurements with neptunium metal reflected by high enriched uranium

    International Nuclear Information System (INIS)

    Valentine, Timothy E.; Mattingly, John K.

    2003-01-01

    Subcritical noise analysis measurements have been performed with neptunium ( 237 Np) sphere reflected by highly enriched uranium. These measurements were performed at the Los Alamos Critical Experiment Facility in December 2002 to provide an estimate of the subcriticality of 237 Np reflected by various amounts of high-enriched uranium. This paper provides a description of the measurements and presents some preliminary results of the analysis of the measurements. The measured and calculated spectral ratios differ by 15% whereas the 'interpreted' and calculated k eff values differ by approximately 1%. (author)

  3. Neptunium(V) sorption on quartz and albite in aqueous suspension

    International Nuclear Information System (INIS)

    Kohler, M.; Leckie, J.O.

    1991-10-01

    The behavior of neptunium in the subsurface environment is of interest since neptunium isotopes are included in nuclear waste. Previous work investigated the sorption behavior of Np onto α-Fe 2 O 3 (hematite), an accessory mineral of the Yucca Mountain repository. The work reported herein involves the much more abundant silicate minerals quartz and albite, and is a logical continuation of the ongoing task. In previous work increased sorption was observed in systems containing hematite and EDTA, a ligand which acts as a surrogate for organic complexing agents. In addition, increased partial pressures of CO 2 are common in many ground waters and the effects of carbonate on sorption of radionuclides have to be studied as well. At concentration levels of 10 -7 M, Np(V) does not adsorb strongly on quartz and albite up to pH values of approximately 9 at solid/solution ratios of 30 to 40 g/l. Significant adsorption (> 20%) occurs on both minerals only at pH > 9. Pretreatment of albite affects the sorption behavior of this mineral at pH > 9, possibly due to the formation of secondary mineral phases at the albite surface. EDTA does not adsorb on quartz at concentrations of 10 -6 M. In the presence of 50 μM EDTA, Np(V) sorption seems to be restricted. EDTA at the 10 -6 M level adsorbs onto albite to an appreciable degree at pH values 3 - is the predominant solution species

  4. Study of oxidation-reduction reactions of plutonium and neptunium in sulphuric-phosphoric acid media

    International Nuclear Information System (INIS)

    Moiseev, I.V.; Kuperman, A.Ya.; Borodina, N.N.; Galkina, V.N.; Vinokurov, V.A.

    1976-01-01

    Potentiostatic, coulometric, potentiometric, and amperometric methods have been used for determining the rate constants of disproportionation (ksub(d)) of plutonium(5) and neptunium (5) and normal real redox potentials (Esub(0)sup(p)) of the following ion pairs in sulphur-phosphoric-acid media: PuOsub(2)sup(2)sup(+) (PuO 2 + , Pu 4+ /Pu 3+ , NpO 2 2+ /NpO 2 + , NpO 2 2+ /Np 4+ , NpO 2 + /Np 4+ , and Fe 3+ /Fe 2+ . The regularities have been shown of changing ksub(d) and Esub(o)sup(p) as a function of H 2 SO 4 and H 3 PO 4 concentration. It has been established that for plutonium and neptunium a linear correlation is observed between lg ksub(d) and Esub(o)sup(p) of the ion pairs NpO 2 2+ /NpO 2 + , NpO 2 2 /Np 4+ , NpO 2 + /Np 4+ and PuO 2 2+ /PuO 2 + in a wide range of their values. The correlation coefficient is close to unity in all cases (no less than 0.96). The results of investigations have made it possible to recommend optimum compositions of background electrolytes for performing continuous amperostatic coulometric titration of Pusup((6)) and Npsup((6)) up to four valent state by electrogenerated ions of iron (2)

  5. Study of extraction chromatography methods of separation of neptunium and its radiometric determination

    International Nuclear Information System (INIS)

    Reich, M.

    2009-04-01

    In presented dissertation thesis the separation procedure for determination of neptunium in model solutions and also in soil samples was designed. 1. The sorbent was prepared on basis of hydrophobised silica gel with silica oil for hydrophobisation - Lukooil H. Extraction agent was anchored on this modified surface -quarternary ammonium salt Aliquat 336. In experiments was proved, that sorbent prepared like this is resist enough to the elution solutions using in separation procedures. It was found out that maximal concentration of deposited Aliquat 336 in benzene on hydrophobised silica gel selected granulate size is 40%. Sorbent prepared with silica gel lower granulate size and also with higher concentration of Aliquat 336 in benzene became sticky and unsuitable for using in separation columns. 2. The prepared sorbent is similar to commercial produced TEVA resin made by company Eichrom and for purpose of this project it was cheaper but the same effective alternative in comparing to mentioned commercial resin. 3. The separation procedure for isolation of 237 Np from radionuclides interfering during its radiometric determination with alpha spectrometry was designed -in scientific publications hasn't been described yet. The procedure consists of using formic acid for reduction of radionuclides interfering by alpha spectrometric determination of 237 Np and subsequent purification of neptunium on the next column by using ferrous sulphamate as reduction agent. This procedure was applied to the model solutions and also to the soil samples. The model solutions and soil samples for these experiments were contaminated with known amounts of 237 Np, 238 pU, 232 Th and mixture of 234 U/ 238 U. The effective separation of neptunium from described radionuclides was achieved with application of the described separation procedure. 4. The separation procedure for separation of 239 Np from its mother radionuclide 241 Am was designed with prepared sorbent. Different washing and

  6. Sorption and direct speciation of neptunium(V) on aluminium oxide and montmorillonite

    International Nuclear Information System (INIS)

    Wendt, Sonja

    2009-01-01

    This study comprised batch experiments, direct speciation studies via EXAFS, and modelling with the 2SPNE SC/CE model to elucidate the mechanisms of Np(V) sorption on montmorillonite and, for reference, on γ-Al 2 O 3 . The sorption of pM 239 Np(V) and μM 237 Np(V) on montmorillonite (STx-1, 4 g/L) and γ-Al 2 O 3 (0.5 g/L) was studied at room temperature in the presence and absence of ambient CO 2 covering a pH-range from 2.5 (STx-1) or 5 (γ-Al 2 O 3 ) to 10.5 with 0.01 or 0.1M NaClO 4 as background electrolyte. The Np(V) uptake was determined by γ spectroscopy of the supernatants and calculated as percentage as well as distribution coefficient K d . Sorption starts from pH ∼6 and, under exclusion of CO 2 , increases continuously, while, in the presence of ambient air, it reaches a maximum at pH ∝8.5 (γ-Al 2 O 3 : logK d max ∼ 4 mL/g; STx-1: logK d max ∼ 2.7 mL/g). Beyond that it decreases again due to the formation of aqueous neptunium carbonate complexes. Furthermore, neptunium sorption on montmorillonite is influenced by ionic strength at pH <6 through ion exchange processes pointing towards the formation of outer-sphere surface complexes there. Isotherms measured at the sorption maximum showed the precipitation of presumably neptunium carbonate complexes above 3.10 -5 M under ambient air conditions. Additionally, they indicated progressive saturation of the sorption sites of γ-Al 2 O 3 . At selected pH (STx-1: 5.0, 7.0, 8.0, 8.5, 9.0, 9.5; γ-Al 2 O 3 : 8.5, 9.5) EXAFS samples were prepared as wet pastes with μM 237 Np and measured at room temperature in fluorescence mode at ANKA and ESRF. Several spectra were averaged and analysed with EXAFSPAK and FEFF 8.20 employing models of NaNpO 2 (CO 3 ) or soddyite, (UO 2 ) 2 SiO 4 .2(H 2 O). The shorter atomic distances of the neptunyl ion at pH 5 compared to the others hinted at the retention of the hydration shell and, thus, at outer-sphere sorption. On average the bond lengths for Np(V) sorbed on STx

  7. The 'overlooked trio' of hypothetical terrorist nuclear weapons - reactor grade plutonium, neptunium-237 and tritium

    International Nuclear Information System (INIS)

    Sholly, S.

    2002-01-01

    Full text: Considerations revolving around physical protection of nuclear material are quite commonly and naturally focused on protecting weapons-grade plutonium (WGPu) and highly enriched uranium (HEU) from theft and diversion. These two materials are the center of attention because of their well-known (and demonstrated) potential for use in first-generation nuclear explosive devices of which potential terrorists are widely thought to be capable. They are also the center of attention because of retirements of these materials from military use as the Russian Federation and the United States reduce the number of nuclear weapons in their arsenals. Three other materials - an 'overlooked trio' - must also be borne in mind within this context: (1) reactor-grade plutonium (RGPu); (2) neptunium-237 (Np-237); and (3) tritium (H-3). Although there are still some authorities who either contend that RGPu cannot be used in a nuclear explosive or that there are (for a terrorist) insurmountable difficulties in doing so, the knowledgeable scientific and technical community, recognizes the potential utility of RGPu for hypothetical terrorist nuclear devices. A much smaller community of experts recognizes the usefulness of Np-237 for nuclear devices, but Np-237 is as straight-forwardly and easily usable as HEU and similarly abundant (but not often in separated form). Tritium can be used (with a modest increase in design sophistication) in a conventional first-generation nuclear device with any of the weapons-usable materials (WGPu, HEU, RGPu or Np-237) to increase the yield and/or increase the reliability of a non-fizzle yield. Given the presence of RGPu and Np-237 in abundant quantities in spent commercial reactor fuel, widely available knowledge of how to separate these materials, and a world-wide total of more than 400 nuclear power plants, spent reactor fuel also requires stringent controls. This is especially true of old spent fuel which has far less radiation dose

  8. Neptunium(V) Adsorption to Bacteria at Low and High Ionic Strength

    Science.gov (United States)

    Ams, D.; Swanson, J. S.; Reed, D. T.

    2010-12-01

    Np(V) is expected to be the predominant oxidation state of neptunium in aerobic natural waters. Np(V), as the NpO2+ aquo and associated complexed species, is readily soluble, interacts weakly with geologic media, and has a high redox stability under a relatively wide range of subsurface conditions. These chemical properties, along with a long half-life make it a primary element of concern regarding long-term nuclear waste storage and subsurface containment. The fate and transport of neptunium in the environment may be influenced by adsorption onto bacterial surfaces. The adsorption of neptunium to bacterial surfaces ties the mobility of the contaminant to the mobility of the bacterium. In this study, the adsorption of the neptunyl (NpO2+) ion was evaluated at low ionic strength on a common soil bacterium and at high ionic strength on a halophilic bacterium isolated from a briny groundwater near the Waste Isolation Pilot Plant (WIPP) in southeast New Mexico. Adsorption experiments were performed in batch reactors as a function of pH, ionic strength, and bacteria/Np mass ratio. Np(V) adsorption was modeled using a surface complexation approach with the mathematical program FITEQL to determine functional group specific binding constants. The data from acid and base titrations of the bacteria used were also modeled to estimate the concentrations and deprotonation constants of discrete bacterial surface functional groups. Bacterial functional group characteristics and Np(V) adsorption behavior between the soil bacterium and the halophilic bacterium were compared. These results highlight key similarities and differences in actinide adsorption behavior in environments of significantly different ionic strength. The observed adsorption behavior may be linked to similarities and differences in the characteristics of the moieties between the cell walls of common gram-negative soil and halophilic bacteria. Moreover, differences in adsorption behavior may also reflect ionic

  9. Neptunium(V) adsorption to bacteria at low and high ionic strength

    International Nuclear Information System (INIS)

    Ams, David A.; Swanson, Juliet S.; Reed, Donald T.; Fein, Jeremy B.

    2010-01-01

    Np(V) is expected to be the predominant oxidation state of neptunium in aerobic natural waters. Np(V), as the NpO 2 + aquo and associated complexed species, is readily soluble, weakly interacting with geologic media, and has a high redox stability under a relatively wide range of subsurface conditions. These chemical properties, along with a long half-life make it a primary element of concern regarding long-term nuclear waste storage and subsurface contaminant. The fate and transport of neptunium in the environment may be influenced by adsorption onto bacterial surfaces. The adsorption of neptunium to bacterial surfaces ties the mobility of the contaminant to the mobility of the bacterium. In this study, the adsorption of the neptunyl (NpO 2 + ) ion was evaluated at low ionic strength on a common soil bacterium and at high ionic strength on a halophilic bacterium isolated from a briny groundwater near the Waste Isolation Pilot Plant (WIPP) in southeast New Mexico. Adsorption experiments were performed in batch reactors as a function of pH, ionic strength, and bacterialNp mass ratio. Np(V) adsorption was modeled using a surface complexation approach with the mathematical program FITEQL to determine functional group specific binding constants. The data from acid and base titrations of the bacteria were also modeled to estimate the concentrations and deprotonation constants of discrete bacterial surface functional groups. Bacterial functional group characteristics and Np(V) adsorption behavior between the soil bacterium and the halophilic bacterium were compared. These results highlight the key similarities and differences in actinide adsorption behavior in environments of significantly different ionic strength. Similarities in adsorption behavior may be linked to similarities in the characteristics of the moieties between all bacterial cell walls. Differences in adsorption behavior may reflect differences in ionic strength effects, rather than differences in bacteria

  10. Neptunium(V) adsorption to bacteria at low and high ionic strength

    Energy Technology Data Exchange (ETDEWEB)

    Ams, David A [Los Alamos National Laboratory; Swanson, Juliet S [Los Alamos National Laboratory; Reed, Donald T [Los Alamos National Laboratory; Fein, Jeremy B [UNIV OF NOTRE DAME

    2010-12-08

    Np(V) is expected to be the predominant oxidation state of neptunium in aerobic natural waters. Np(V), as the NpO{sub 2}{sup +} aquo and associated complexed species, is readily soluble, weakly interacting with geologic media, and has a high redox stability under a relatively wide range of subsurface conditions. These chemical properties, along with a long half-life make it a primary element of concern regarding long-term nuclear waste storage and subsurface contaminant. The fate and transport of neptunium in the environment may be influenced by adsorption onto bacterial surfaces. The adsorption of neptunium to bacterial surfaces ties the mobility of the contaminant to the mobility of the bacterium. In this study, the adsorption of the neptunyl (NpO{sub 2}{sup +}) ion was evaluated at low ionic strength on a common soil bacterium and at high ionic strength on a halophilic bacterium isolated from a briny groundwater near the Waste Isolation Pilot Plant (WIPP) in southeast New Mexico. Adsorption experiments were performed in batch reactors as a function of pH, ionic strength, and bacterialNp mass ratio. Np(V) adsorption was modeled using a surface complexation approach with the mathematical program FITEQL to determine functional group specific binding constants. The data from acid and base titrations of the bacteria were also modeled to estimate the concentrations and deprotonation constants of discrete bacterial surface functional groups. Bacterial functional group characteristics and Np(V) adsorption behavior between the soil bacterium and the halophilic bacterium were compared. These results highlight the key similarities and differences in actinide adsorption behavior in environments of significantly different ionic strength. Similarities in adsorption behavior may be linked to similarities in the characteristics of the moieties between all bacterial cell walls. Differences in adsorption behavior may reflect differences in ionic strength effects, rather than

  11. PIVET rFSH dosing algorithms for individualized controlled ovarian stimulation enables optimized pregnancy productivity rates and avoidance of ovarian hyperstimulation syndrome.

    Science.gov (United States)

    Yovich, John L; Alsbjerg, Birgit; Conceicao, Jason L; Hinchliffe, Peter M; Keane, Kevin N

    2016-01-01

    The first PIVET algorithm for individualized recombinant follicle stimulating hormone (rFSH) dosing in in vitro fertilization, reported in 2012, was based on age and antral follicle count grading with adjustments for anti-Müllerian hormone level, body mass index, day-2 FSH, and smoking history. In 2007, it was enabled by the introduction of a metered rFSH pen allowing small dosage increments of ~8.3 IU per click. In 2011, a second rFSH pen was introduced allowing more precise dosages of 12.5 IU per click, and both pens with their individual algorithms have been applied continuously at our clinic. The objective of this observational study was to validate the PIVET algorithms pertaining to the two rFSH pens with the aim of collecting ≤15 oocytes and minimizing the risk of ovarian hyperstimulation syndrome. The data set included 2,822 in vitro fertilization stimulations over a 6-year period until April 2014 applying either of the two individualized dosing algorithms and corresponding pens. The main outcome measures were mean oocytes retrieved and resultant embryos designated for transfer or cryopreservation permitted calculation of oocyte and embryo utilization rates. Ensuing pregnancies were tracked until live births, and live birth productivity rates embracing fresh and frozen transfers were calculated. Overall, the results showed that mean oocyte numbers were 10.0 for all women algorithms in our clinic meant that the starting dose was not altered for 79.1% of patients and for 30.1% of those receiving the very lowest rFSH dosages (≤75 IU). Only 0.3% patients were diagnosed with severe ovarian hyperstimulation syndrome, all deemed avoidable due to definable breaches from the protocols. The live birth productivity rates exceeded 50% for women algorithms led to only 11.6% of women generating >15 oocytes, significantly lower than recently published data applying conventional dosages (38.2%; Palgorithms to each other, the outcomes were mainly comparable for

  12. Method of purification of solutions containing plutonium and/or neptunium by plutonium and/or neptunium separation

    Energy Technology Data Exchange (ETDEWEB)

    Herz, D; Kankura, R; Wenzel, U

    1975-03-27

    Aqueous solutions containing, amongst other radiation sources, 10/sup -2/ to 10/sup -7/ mol per litre Pu and/or Np - especially aqueous solutions produced when reprocessing fuel elements, in particular of HTR reactors, e.g. according to the Thorex process - can be cleaned from the two metals without much expenditure by using a separating column: determination of the H/sup +/ ion concentration (0.5-6 mol/litre solution), addition of a stabilizing agent (NaNO/sub 2/ or Fe (NH/sub 2/SO/sub 3/)/sub 2/) and passage across a separating column in which the granulate charge is wetted with a long-chain alkylamine (e.g. trioctylamine) which retains the metal. The production of a charge (of Voltalef UF 300) is described. The process may also be carried out continuously.

  13. Investigation of separation factors of neptunium and plutonium in the process of mass transfer through liquid impregnated membranes with di-2-ethylhexylphosphoric acid

    International Nuclear Information System (INIS)

    Novikov, A.P.; Mikheeva, M.N.; Myasoedov, B.F.

    1990-01-01

    Kinetics of joint transfer of neptunium(6) and plutonium(4) through liquid membranes with di-2-ethylhexylphosphoric acid, depending on the concentration of the carrier, nature of reextracting agent and ratio of metal concentrations, was investigated. The optimal conditions for selective isolation of microimpurity of one of the elements from solutions of the other were determined. Solution of ammonium carbonate with carrier concentration of 0.1-0.2 mol/l can be expediently utilized as reextracting phase for neptunium impurity removal

  14. Structural variability in neptunium(V) oxalate compounds: synthesis and structural characterization of Na2NpO2(C2O4)OH.H2O.

    Science.gov (United States)

    Bean, Amanda C; Garcia, Eduardo; Scott, Brian L; Runde, Wolfgang

    2004-10-04

    Reaction of a (237)Np(V) stock solution in the presence of oxalic acid, calcium chloride, and sodium hydroxide under hydrothermal conditions produces single crystals of a neptunium(V) oxalate, Na(2)NpO(2)(C(2)O(4))OH.H(2)O. The structure consists of one-dimensional chains running down the a axis and is the first example of a neptunium(V) oxalate compound containing hydroxide anions.

  15. Sorption of cesium, radium, protactinium, uranium, neptunium and plutonium on rapakivi granite

    International Nuclear Information System (INIS)

    Huitti, T.; Hakanen, M.

    1996-12-01

    The aim of the study is to determine the sorption of cesium, radium, protactinium, uranium, neptunium and plutonium on rapakivi granite in the brackish groundwater of Haestholmen (site of the Loviisa-1, Loviisa-2 reactors). The studies were carried out under aerobic (Cs, Ra, Pa, U, Np, Pu) and anaerobic (Np, Pa, Pu, Tc) laboratory conditions. The cation exchange capasity was determined for the rock and the diffusion of tritiated water in the rocks of different degree of alteration. The sorption and diffusion properties of the rocks are briefly compared with those of host rocks at other sites under investigation by the Finnish company Posiva Oy for the final disposal of spent fuel. (29 refs.)

  16. Effect of mass of neptunium V in intestinal absorption in the monkey and the rat

    International Nuclear Information System (INIS)

    Metivier, H.; Masse, R.; Lafuma, J.

    1983-01-01

    The coefficient of gastrointestinal transfer of neptunium as pentavalent neptunyl nitrate was studied in rats and monkeys as a function of the ingested mass. In both species, the transfer coefficient ranged between 1.10 - 3 - 1.10 - 2 when the administered mass varied from 0.3 ng to 2 mg per kg. At low concentrations, the values obtained in the monkey are about twice as low as thoses obtained in the rat. Considering the strong urinary excretion, the amounts retained at the organ levels represent about 0.1% in the rat and 0.04% in the monkey for low concentrations. The values obtained are usually in good agreement with the few data published on the rat [fr

  17. Gamma radiolysis of alkaline aqueous solutions of neptunium and plutonium ions

    International Nuclear Information System (INIS)

    Pikaev, A.K.; Gogolev, A.V.; Shilov, V.P.

    1998-01-01

    Full text: The paper is a brief review of data obtained by the authors from the study on redox reactions of neptunium and plutonium ions upon γ radiolysis of their aerated alkaline aqueous solutions. It includes the information on radiolytic reduction of Np(V), Np(VI) and Pu(VI) ions under various experimental conditions. It was found that the values of Np(VI) and Pu(VI) reduction yields do not depend on alkali concentration. The values considerably increase in the presence of some organic compounds (EDTA and formate were investigated). The formation of the Np(V) peroxo complex was observed in the γ radiolysis of alkaline aqueous solutions of Np(VI) and Np(V) in the presence of nitrate. The mechanism of radiolytic redox reactions of the ions is discussed in some detail

  18. Separation of neptunium from uranium and plutonium in the Purex process

    International Nuclear Information System (INIS)

    Kolarik, Z.; Schuler, R.

    1984-01-01

    The possibility of removing neptunium from the Purex process in the first extraction cycle was investigated. Butyraldehyde was found to reduce Np(VI) to Np(V), but not Pu(IV) to Pu(III). Up to 99.7% Np can be separated from uranium and plutonium in the 1A extractor or, much more favourably, in an additional partitioning extractor. Hydroxylamine nitrate can be used for reducing Np(VI) to Np(V) in a uranium purification cycle at a high U concentration in the feed solution. Here the decontamination factor for Np can be as high as 2300 and is lowered if iron is present in the feed. (author)

  19. Uranium, neptunium and plutonium kinetics of extraction by tributylphosphate and trilaurylamine in a centrifugal contactor

    International Nuclear Information System (INIS)

    Bergeonneau, P.; Jaouen, C.; Germain, M.; Bathellier, A.

    1977-01-01

    Uranium, plutonium and neptunium kinetics of transfer between various aqueous nitric solutions and solvents have been measured at the laboratory scale, using a centrifugal contactor especially developed in the laboratory. The transfer kinetics of nitric acid, hexavalent U, tetravalent U, Np and Pu from nitric acid solutions into 30% TBP in r-dodecane and 10% trilaurylamine in r-dodecane have been studied. The effects of rotation speed, temperature, initial nitric acid concentration, metal concentration on extraction and stripping kinetics have been investigated. The results obtained show that TBP extraction and stripping are more rapid than trilaurylamine ones. The low activation energies of transfer reactions with TBP suggest that both in extraction and stripping, the transfer rate is limited by the diffusion of the species in the aqueous and organic phases. For trilaurylamine, the transfer mechanism appears more complex

  20. PIVET rFSH dosing algorithms for individualized controlled ovarian stimulation enables optimized pregnancy productivity rates and avoidance of ovarian hyperstimulation syndrome

    Directory of Open Access Journals (Sweden)

    Yovich JL

    2016-08-01

    79.1% of patients and for 30.1% of those receiving the very lowest rFSH dosages (≤75 IU. Only 0.3% patients were diagnosed with severe ovarian hyperstimulation syndrome, all deemed avoidable due to definable breaches from the protocols. The live birth productivity rates exceeded 50% for women <35 years and was 33.2% for the group aged 35–39 years. Routine use of both algorithms led to only 11.6% of women generating >15 oocytes, significantly lower than recently published data applying conventional dosages (38.2%; P<0.0001. When comparing both specific algorithms to each other, the outcomes were mainly comparable for pregnancy, live birth, and miscarriage rate. However, there were significant differences in relation to number of oocytes retrieved, but the mean for both the algorithms remained well below 15 oocytes. Consequently, application of both these algorithms in our in vitro fertilization clinic allows the use of both the rFSH products, with very similar results, and they can be considered validated on the basis of effectiveness and safety, clearly avoiding ovarian hyperstimulation syndrome. Keywords: IVF, OHSS, AFC, AMH, BMI

  1. Sequential injection approach for simultaneous determination of ultratrace plutonium and neptunium in urine with accelerator mass spectrometry

    DEFF Research Database (Denmark)

    Qiao, Jixin; Hou, Xiaolin; Roos, Per

    2013-01-01

    An analytical method was developed for simultaneous determination of ultratrace level plutonium (Pu) and neptunium (Np) using iron hydroxide coprecipitation in combination with automated sequential injection extraction chromatography separation and accelerator mass spectrometry (AMS) measurement...... show that preboiling and aging are important for obtaining high chemical yields for both Pu and Np, which is possibly related to the aggregation and adsorption behavior of organic substances contained in urine. Although the optimal condition for Np and Pu simultaneous determination requires 5-day aging...

  2. X-ray photoemission spectroscopy (XPS) study of uranium, neptunium and plutonium oxides in silicate-based glasses

    International Nuclear Information System (INIS)

    Lam, D.J.; Veal, B.W.; Paulikas, A.P.

    1982-11-01

    Using XPS as the principal investigative tool, we are in the process of examining the bonding properties of selected metal oxides added to silicate glass. In this paper, we present results of XPS studies of uranium, neptunium, and plutonium in binary and multicomponent silicate-based glasses. Models are proposed to account for the very diverse bonding properties of 6+ and 4+ actinide ions in the glasses

  3. The redox chemistry of neptunium in gamma-irradiated aqueous nitric acid in the presence of an organic phase

    Czech Academy of Sciences Publication Activity Database

    Mincher, B.J.; Přeček, Martin; Paulenova, A.

    2016-01-01

    Roč. 308, č. 3 (2016), s. 1005-1009 ISSN 0236-5731 R&D Projects: GA MŠk EE2.3.30.0057 Grant - others:OP VK 4 POSTDOK(XE) CZ.1.07/2.3.00/30.0057 Institutional support: RVO:68378271 Keywords : neptunium * redox chemistry * radiation chemistry * solvent extraction Subject RIV: CH - Nuclear ; Quantum Chemistry OBOR OECD: Inorganic and nuclear chemistry Impact factor: 1.282, year: 2016

  4. Tax Avoidance, Welfare Transfers, and Asset Prices

    OpenAIRE

    Denis Gorea

    2013-01-01

    Does tax avoidance have any implications for financial markets? This paper quantifies the general equilibrium implications of tax avoidance by setting up an incomplete markets production economy model in which households pay capital gains taxes and have access to tax avoidance technologies provided by financial institutions. I find that changes in the level of tax avoidance have disproportionate effects on different groups of agents and generally benefit the old, wealthy and high income house...

  5. Neptunium(V) sorption onto kaolinite in the absence and presence of CO2

    International Nuclear Information System (INIS)

    Amayri, S.; Reich, Ta.; Reich, T.

    2005-01-01

    Full text of publication follows: The adsorption of heavy metals on clay minerals such as kaolinite is an important process that affects the migration and retardation of neptunium and other actinides in the geosphere. The sorption of Np(V) onto the reference clay mineral kaolinite KGa-1b was investigated both by batch experiments and EXAFS measurements. The aim of our study was to combine macroscopic studies (batch experiments) with microscopic techniques (EXAFS) to study the Np(V) speciation at the kaolinite surface. The batch experiments were done under relevant environmental conditions with Np(V) concentrations of 10 -11 and 10 -12 mol/L. Sorption samples were prepared in 0.1 mol/L NaClO 4 , 4 g/L kaolinite, pH 6.0 to 10.5, presence and absence of ambient CO 2 , and 60-h equilibration. The sorption curves for 10 -11 and 10 -12 mol/L Np(V) obtained in the presence and absence of CO 2 , respectively, show that the adsorption edge occurs at pH 8.5. The uptake of Np(V) by kaolinite strongly increased above pH 7.0 and reached its sorption maximum (70 %) at pH 9.0. Above pH 9.0, the amount of Np(V) sorbed onto kaolinite decreased and reached ca. 30 % at pH 10.5 due to the formation of Np(V) carbonato species in the aqueous solution. In the CO 2 -free system, the sorption of Np(V) increased continuously with pH until the sorption maximum of 100 % was reached at pH 10.5. The same sorption behavior was found in batch experiments in the CO 2 equilibrated system with Np concentrations ranging from 1 μmol/L to 10 μmol/L. EXAFS experiments on some of these batch samples indicated the formation of Np(V) carbonato species at the kaolinite surface at pH 9.0 where the uptake of Np(V) by kaolinite reaches its maximum [1]. [1] T. Reich, S. Amayri, Ta. Reich, J. Drebert, A. Jermolajev, P. Thoerle, N. Trautmann, C. Hennig, S. Sachs, Feasibility of EXAFS experiments at the Np L-edge to investigate neptunium sorption on kaolinite, Institut fuer Kernchemie, Universitaet Mainz, Annual

  6. The recycling of the actinides neptunium, americium and curium in a fast power reactor to reduce the long term activity in a final store

    International Nuclear Information System (INIS)

    Beims, H.D.

    1986-01-01

    The starting point for the considerations and calculations given in this dissertation is the inevitable production of radioactive materials in the use of nuclear energy, which creates a considerable potential danger in a final store for a very long period. As one possibility of alleviating this problem, a concept for recycling the waste actinides neptunium, americium and curium was proposed. The waste actinides are separated in the reprocessing of burnt-up fuel elements and reach a further irradiation circuit. There they pass through the stages 'manufacture of irradiation elements', 'use in a fast power reactor' and reprocessing of irradiation elements' several times. In each irradiation and subsequent storage, about 17% of the waste actinides are removed by fission or by conversion into nuclides which can be reused as fuel, so that during the life of 40 years of the fast recycling reacor, the waste actinides can be reduced in mass by one half. In order to determine this mass reduction effect, a model calculation was developed, which includes the representation of the neutron physics and thermal properties of the reactor core and the storage and reprocessing of the irradiation elements. (orig./RB) [de

  7. Application of extraction chromatography to the recovery of neptunium, plutonium and americium from an industrial waste

    International Nuclear Information System (INIS)

    Madic, C.; Kertesz, C.; Sontag, R.; Koehly, G.

    1980-01-01

    A pilot scale investigation was made to evaluate the possible application of the extraction chromatographic method (LLC) to the partitioning of alpha emitters from liquid wastes containing traces of transuranium elements. A secondary purpose was to obtain pure Am0 2 , which is used to produce alpha, gamma, and neutron sources. The process developed for alpha partitioning consists essentially of the extraction of macro amounts of uranium with 30% TBP in dodecane in mixer-settlers, then coextraction of Np-237, Pu-239, and Am-241 by LLC on a macro column filled with di-n-hexyl-octoxy-methyl-phosphine oxide (POX.11) adsorbed on an inert support. In each run about 200 liters of initial waste are decontaminated of alpha emitters. The loading step is followed by selective elution of americium, neptunium, and plutonium. The americium eluate is then subjected to the following operations: (1) separation of Am from Fe and Cd by LLC on a TBP column and (2) separation of Am from lanthanide traces by LLC on an HD(DiBM)P column after oxidation of Am(III) to Am(VI). The Am in the eluate is subsequently reduced to Am(III) and precipitated as oxalate with oxalic acid. The oxalate is then filtered and calcined to yield pure AmO 2

  8. Investigation on neptunium behavior in electrolytic partitioning process of uranium and plutonium

    International Nuclear Information System (INIS)

    Zhang Qingxuan; Zhang Jiajun; Tian Baosheng; Jiang Dongliang; Li Zhaoyi; He Jianyu

    1988-01-01

    The electrolytic oxidation-raduction of Np(V, VI) in HNO 3 solution was studied. Experimental results showed that the electrode process of Np(V)-Np(VI) couple is reversible, and the half reaction time of the process mentioned above is about 1.5 minutes under given conditions. The overpotential of reduction of Np(V) is high, which makes it difficult to reduce Np(V) into Np(IV) directly at cathode. Owing to a large quantity of U(IV) produced through electrolysis, it is presaged that neptunium will be mainly in tetravalent state in the electrolytic M-S battery. A new type of electrolytic M-S battery was developed, in which anodes were installed in each settling chamber without any specific anode chamber in the battery. Owing to using of the mechanical stirrer driven by a wheel gear, stage efficiency is high. Demonstration campaign was carried out. It follows from the results that the yield of Pu is 99.90 ∼ 99.99%. Separation factor of U from Pu is 3900 ∼ 33000. Material balance of U and Pu is satisfactory. Heavy accumulation of Np in the battery was observed. Np in the battery is mainly in the tetravalent state. It is believed that it is difficult to recover Np quantitatively from single fluent (e.g. 1BP or 1BU) under normal conditions of partitioning step of the PUREX process

  9. Computational Study on Mössbauer Isomer Shifts of Some Organic-neptunium (IV Complexes

    Directory of Open Access Journals (Sweden)

    Masashi Kaneko

    2015-12-01

    Full Text Available Relativistic DFT calculations are applied to some organo-neptunium (IV complexes, Cp3NpIVX (Cp = η5-C5H5; X = BH4, Cl, OtBu, Ph, nBu, in order to understand their bonding properties between Np and the ligands. We employ scalar-relativistic ZORA Hamiltonian with all-electron basis set (SARC. The calculated electron densities at Np nucleus position in the complexes at B2PLYP / SARC theory strongly correlate to the experimental Mössbauer isomer shifts of 237Np system. The result of bond overlap population analysis indicates that the bonding strength decreases in order of X = BH4, Cl, OtBu, Ph and nBu. The tendency depends on the degree of the covalent interaction between Np 5f-electron and X ligand. It is suggested that it is important to estimate the bonding contribution of 5f-orbital to understand the electronic state for organo-actinide complexes.

  10. Creation of a simplified benchmark model for the neptunium sphere experiment

    International Nuclear Information System (INIS)

    Mosteller, Russell D.; Loaiza, David J.; Sanchez, Rene G.

    2004-01-01

    Although neptunium is produced in significant amounts by nuclear power reactors, its critical mass is not well known. In addition, sizeable uncertainties exist for its cross sections. As an important step toward resolution of these issues, a critical experiment was conducted in 2002 at the Los Alamos Critical Experiments Facility. In the experiment, a 6-kg sphere of 237 Np was surrounded by nested hemispherical shells of highly enriched uranium. The shells were required in order to reach a critical condition. Subsequently, a detailed model of the experiment was developed. This model faithfully reproduces the components of the experiment, but it is geometrically complex. Furthermore, the isotopics analysis upon which that model is based omits nearly 1 % of the mass of the sphere. A simplified benchmark model has been constructed that retains all of the neutronically important aspects of the detailed model and substantially reduces the computer resources required for the calculation. The reactivity impact, of each of the simplifications is quantified, including the effect of the missing mass. A complete set of specifications for the benchmark is included in the full paper. Both the detailed and simplified benchmark models underpredict k eff by more than 1% Δk. This discrepancy supports the suspicion that better cross sections are needed for 237 Np.

  11. Complex formation between neptunium(V) and various thiosemicarbazide derivatives in aqueous solution

    International Nuclear Information System (INIS)

    Chuguryan, D.G.; Dzyubenko, V.I.; Gerbeleu, N.V.

    1987-01-01

    Complex formation between neptunium(V) and various thiosemicarbazide derivatives in solution has been studied spectrophotometrically in the pH range 4-10. Stepwise formation of three types of complexes, with composition NpO 2 HA, NpO 2 A - , and NpOHA 2- , has been demonstrated with salicylaldehyde thiosemicarbazone (H 2 L) and salicylaldehyde S-methyl-isothiosemicarbazone (H 2 Q) at t = 25 +/- 1 0 C and μ = 0.05. The logarithmic stability constants of the first two complexes are 5.14 +/- 0.06, 11.85 +/- 0.04 and 8.42 +/- 0.09, 13.33 +/- 0.015 for H 2 L and H 2 Q, respectively; equilibrium constants for the formation of hydroxo complexes of the form NpO 2 OHL 2- and NpO 2 OHQ 2- were also determined, and found to be equal to (2.23 +/-0.37) x 10 -5 and (5.02 +/- 0.9) x 10 -5 , respectively. In the case of S-methyl-N 1 ,N 4 -bis(salicylidene)isothiosemicarbazide (H 2 Z), only one type of complex is formed under these experimental conditions, namely, NpO 2 Z - , with a logarithmic stability constant of 4.78 +/- 0.03. Dissociation constants for H 2 Q and H 2 Z were also determined

  12. Rapid and simultaneous determination of neptunium and plutonium isotopes in environmental samples by extraction chromatography using sequential injection analysis and ICP-MS

    DEFF Research Database (Denmark)

    Qiao, Jixin; Hou, Xiaolin; Roos, Per

    2010-01-01

    plutonium and neptunium in three reference materials were in agreement with the recommended or literature values at the 0.05 significance level. The developed method is suitable for the analysis of up to 10 g of soil and 20 g of seaweed samples. The extraction chromatographic separation within the SI system......This paper reports an automated analytical method for rapid and simultaneous determination of plutonium isotopes (239Pu and 240Pu) and neptunium (237Np) in environmental samples. An extraction chromatographic column packed with TrisKem TEVA® resin was incorporated in a sequential injection (SI...... for a single sample takes less than 1.5 h. As compared to batchwise procedures, the developed method significantly improves the analysis efficiency, reduces the labor intensity and expedites the simultaneous determination of plutonium and neptunium as demanded in emergency actions....

  13. Complexation of neptunium(V) by salicylate, phthalate and citrate ligands in a pH 7.5 phosphate buffered system

    International Nuclear Information System (INIS)

    Rees, T.F.; Daniel, S.R.

    1984-01-01

    Conditional stability constants, enthalpies and entropies of complexation at pH 7.5 and ionic strength 0.1 have been determined for neptunium(V) complexes of phosphate, salicylate, phthalate and citrate. Results are given and discussed. At pH 7.5 salicylate does not form a complex with neptunium(V) due to the low charge density of the NpO 2 + ion and incomplete ionization of the salicylate ion. In all cases, only 1:1 complexes were identified. (U.K.)

  14. The reduction of plutonium (IV) and neptunium (VI) ions by N,N-ethyl (hydroxyethyl) hydroxylamine in nitric acid

    International Nuclear Information System (INIS)

    Koltunov, V.S.; Baranov, S.M.; Mezhov, E.A.; Taylor, R.J.; May, I.

    1999-01-01

    The kinetics of the reduction of neptunium (VI) and plutonium (IV) ions in nitric acid solution by a new rapid salt free reductant, N,N-ethyl (hydroxyethyl) hydroxylamine, have been studied and rate equations determined. Under equivalent conditions, both Np(VI) and Pu(IV) are reduced faster than by the related reagent, N,N-diethyl hydroxylamine, and it is suggested that this is due to the introduction of the hydroxy group into the reductant molecule. Possible reaction mechanisms have been suggested to account for the observed reaction stoichiometry. (orig.)

  15. The effect of temperature on the sorption of technetium, uranium, neptunium and curium on bentonite, tuff and granodiorite

    International Nuclear Information System (INIS)

    Baston, G.M.N.; Berry, J.A.; Brownsword, M.; Heath, T.G.; Ilett, D.J.; Tweed, C.J.; Yui, M.

    1997-01-01

    A study of the sorption of the radioelements technetium; uranium; neptunium; and curium onto geological materials has been carried out as part of the PNC program to increase confidence in the performance assessment for a high-level radioactive waste repository in Japan. Batch sorption experiments have been performed in order to study the sorption of the radioelements onto bentonite, tuff and granodiorite from equilibrated de-ionized water under strongly-reducing conditions at both room temperature and at 60 C. Mathematical modelling using the geochemical speciation program HARPHRQ in conjunction with the HATCHES database has been undertaken in order to interpret the experimental results

  16. {open_quotes}Transmutation efficiency calculation in the blanket on melted salts with central neptunium target{close_quotes}

    Energy Technology Data Exchange (ETDEWEB)

    Kolesov, V.F.; Shtarev, S.K.; Khoruzhiy, V.K. [Russia Federal Nuclear Center, Arzamas (Russian Federation)] [and others

    1995-10-01

    In the limits of ABC project version of two-sectional reactor system in the form of combination of subcritical blanket on melted salts and multiplying target from threshold fissile material {sup 237}Np is considered. This research is the development of the VNIIEF`s earlier work`s (Russia) investigating of usage possibilities in ABC project the conception of multisectional blankets with single-sided neutron coupling between sections. With the help of Monte-Carlo program the calculations results of system mentioned are given. The possibility of accelerator`s considerable power reduction at the account of thorium target substitution with neptunium-237 multiplying target is shown.

  17. Fuel saving, carbon dioxide emission avoidance, and syngas production by tri-reforming of flue gases from coal- and gas-fired power stations, and by the carbothermic reduction of iron oxide

    International Nuclear Information System (INIS)

    Halmann, M.; Steinfeld, A.

    2006-01-01

    Flue gases from coal, gas, or oil-fired power stations, as well as from several heavy industries, such as the production of iron, lime and cement, are major anthropogenic sources of global CO 2 emissions. The newly proposed process for syngas production based on the tri-reforming of such flue gases with natural gas could be an important route for CO 2 emission avoidance. In addition, by combining the carbothermic reduction of iron oxide with the partial oxidation of the carbon source, an overall thermoneutral process can be designed for the co-production of iron and syngas rich in CO. Water-gas shift (WGS) of CO to H 2 enables the production of useful syngas. The reaction process heat, or the conditions for thermoneutrality, are derived by thermochemical equilibrium calculations. The thermodynamic constraints are determined for the production of syngas suitable for methanol, hydrogen, or ammonia synthesis. The environmental and economic consequences are assessed for large-scale commercial production of these chemical commodities. Preliminary evaluations with natural gas, coke, or coal as carbon source indicate that such combined processes should be economically competitive, as well as promising significant fuel saving and CO 2 emission avoidance. The production of ammonia in the above processes seems particularly attractive, as it consumes the nitrogen in the flue gases

  18. Solubility of neptunium and technetium dioxides in a Yucca Mountain simulated groundwaters

    International Nuclear Information System (INIS)

    Kulyako, Yu.; Perevalov, S.; Malikov, D.; Myasoedov, B.; Atkins-Duffin, Cynthia E.

    2005-01-01

    Full text of publication follows: Solubility of NpO 2 and TcO 2 in the Yucca Mountain simulated ground waters J-13 and UE-25p-1 were studied. It is shown that contents of the dissolved neptunium and technetium in simulated groundwater (SGW) depend on solid/liquid phase ratio in these systems under ambient conditions. Average values of NpO 2 solubility in the suspensions of J-13 SGW are equal to (1.1±0.2) x 10 -6 M, (4.7±0.5) x 10 -6 M and (1.3±0.2) x 10 -5 M at solid/liquid ratios (mg/mL) of 0.4, 2.5 and 9.8 respectively. Average solubility values of NpO 2 in the suspensions of UE-25p-1 SGW are equal to (1.6±0.2) x 10 -7 M, (4.3±0.7) x 10 -7 M and (4.2±1.2) x 10 -6 M for solid/liquid ratios (mg/mL) of 1.2, 3.7 and 18.6, respectively. At equal solid/liquid ratios the solubility of NpO 2 in J-13 SGW is higher than that in UE-25p-1 SGW. At equal contents of solid phase in the suspensions solubility of TcO 2 in J-13 SGW are close to those in UE-25p-1 SGW and they are approximately proportional to the solid/liquid ratio. Average values of TcO 2 solubility in the suspensions of J-13 SGW are equal to (3.0±0.2) x 10 -5 M, (1.7±0.2) x 10 -4 , (6.2±0.2) x 10 -4 M at solid/liquid ratios (mg/mL) of 0.6, 4.8 and 15.5 respectively. Average values of TcO 2 solubility in the suspensions of UE-25p-1 SGW are equal to (5.8±0.3) x 10 -5 M, (2.2±0.1) x 10 -4 M and (3.8±0.2) x 10 -4 M at solid/liquid ratios 1.6, 7.0 and 13.6 (mg/mL) respectively. The dependence of solubility of NpO 2 and TcO 2 on solid/liquid ratio may be explained by the fact that transition of the neptunium and technetium from solid phase into the liquid one occurs on phase interface owing to the dissolving of Np(V) and Tc(VII) compounds being formed under ambient conditions. (authors)

  19. Plutonium and neptunium absorption from the gastrointestinal tract of neonatal baboons

    International Nuclear Information System (INIS)

    Lataillade, Ghislaine; Duserre, Claude; Rateau, Gerard; Verry, Monique; Fritsch, Paul; Metivier, Henri

    1992-06-01

    Nineteen baboons aged 1 to 310 days were given oral doses of 238 Pu citrate or 239 Np nitrate. Gastrointestinal (GI) absorption of Pu and Np were higher than those observed in adults. The values of Pu GI absorption were 0.22% at 1 d, 0.17% at 17 d then about 0.10% until 177 d of age. From 195 d onwards, GI absorption was about 0.02% vs adult values (0.008%). GI absorption of neptunium decreased rapidly with age from 1.71% at 4 d to 0.14% at 6 d and remained at this value until 26 d. From 77 d onwards Np GI absorption was decreased to adult value (0.042%). Gastrointestinal retention associated with GI absorption was small, below 0.4% for Pu and 0.2% for Np. Np and Pu was mainly retained in the small intestine. Pu was retained in the ileum wall till 66 d, and afterwards in the duodenum wall. Histological study of Pu retention showed that it was confined to the macrophages under the ileum villi epithelial cells. Np did not seem to have a well-defined retention compartment. Retention occurred first in the ileum wall up to 6 d, afterwards it was divided between the ileum and duodenum walls up to 77 d and finally, between the duodenum and jejunum walls from 132 days of age onwards. The study shows a difference between Np and Pu GI absorption in neonatal baboons. Np GI absorption decreased to adult value in less than 3 months whereas Pu GI absorption decreased to adult value within 195 days. Our Pu results demonstrated that, the tenfold increase of actinides gastrointestinal transfer proposed by ICRP up to 12 months of age in newborn humans seems acceptable. (authors) [fr

  20. Diffusion and sorption of neptunium(V) in compacted montmorillonite: effects of carbonate and salinity

    International Nuclear Information System (INIS)

    Tachi, Y.; Yotsuji, K.; Suyama, T.; Seida, Y.; Yui, M.; Nakazawa, T.; Yamada, N.; Ochs, M.

    2010-01-01

    Diffusion and sorption of radionuclides in compacted bentonite/montmorillonite are key processes in the safe geological disposal of radioactive waste. In this study, the effects of carbonate and salinity on neptunium(V) diffusion and sorption in compacted sodium montmorillonite were investigated by experimental and modeling approaches. Effective diffusion coefficients (D e ) and distribution coefficients (K d ) of 237 Np(V) in sodium montmorillonite compacted to a dry density of 800 kg m -3 were measured under four chemical conditions with different salinities (0.05/0.5 M NaCl) and carbonate concentrations (0.0.01 M NaHCO 3 ). D e values for carbonate-free conditions were of the order of 10 -10 -10 -11 m 2 s -1 and decreased as salinity increased, and those for carbonate conditions were of the order of 10 -11 -10 -12 m 2 s -1 and showed the opposite dependence. Diffusion-derived K d values for carbonate-free conditions were higher by one order of magnitude than those for carbonate conditions. Diffusion and sorption behaviors were interpreted based on mechanistic models by coupling thermodynamic aqueous speciation, thermodynamic sorption model (TSM) based on ion exchange, and surface complexation reactions, and a diffusion model based on electrical double layer (EDL) theory in homogeneous narrow pores. The model predicted the experimentally observed tendency of D e and K d qualitatively, as a result of the following mechanisms; 1) the dominant aqueous species are NpO 2 + and NpO 2 CO 3 - for carbonate-free and carbonate conditions, respectively, 2) the effects of cation excess and anion exclusion result in opposite tendencies of D e for salinity, 3) higher carbonate in solution inhibits sorption due to the formation of carbonate complexes. (orig.)

  1. Sorption of neptunium(V) on opalinus clay under aerobic/anaerobic conditions

    International Nuclear Information System (INIS)

    Froehlich, D.R.; Amayri, S.; Drebert, J.; Reich, T.

    2011-01-01

    The interaction between neptunium(V) and a natural argillaceous rock (Opalinus Clay (OPA), Mont Terri, Switzerland) has been investigated in batch sorption experiments by varying pH (6-10), Np(V) concentration (10 -12 -10 -4 M), solid-to-liquid ratio (2-20 g/L), and partial pressure of CO 2 (10 -3.5 and 10 -2.3 atm) under aerobic/anaerobic conditions in saturated calcite solution. All batch experiments were carried out using well characterized aerobic and anaerobic dry powders of OPA. The results show a great influence of pH on Np(V) sorption. Under aerobic conditions sorption increases with increasing pH until maximum sorption is reached between pH 8-9. At pH > 9 sorption decreases due to the formation of negatively charged Np(V)-carbonate complexes. By increasing p CO 2 from 10 -3.5 to 10 -2.3 atm, the sorption edge is shifted ∼ 0.5 units to lower pH values. Under anaerobic conditions stronger sorption of 8 x 10 -6 M Np(V) was found, possibly due to partial reduction of Np(V) to Np(IV). The sorption of 8 x 10 -6 M Np(V) under aerobic conditions at pH 8.2 in saturated calcite solution increases continuously with increasing solid-to-liquid ratio of OPA in the range of 2-20 g/L with a constant K d value of 126 ± 13 L/kg. The sorption isotherm was measured over seven orders of magnitude in Np(V) concentration using 239 Np as tracer. The sorption isotherm could be divided in a part of linear sorption behaviour between 10 -13 -10 -9 M Np(V) and non-linear behaviour in the range of 10 -9 -10 -4 M Np(V). (orig.)

  2. Investigation into formation of nanoparticles of tetravalent neptunium in slightly alkaline aqueous solution

    International Nuclear Information System (INIS)

    Husar, Richard

    2015-01-01

    Considering the worldwide growing discharge of minor actinides and the current need for geological disposal facilities for radioactive waste, this work provides a contribution to the safety case concerning Np transport if it would be released from deep repository sites and moving from alkaline cement conditions (near-field) to more neutral environmental conditions (far-field). The reducing conditions in a nuclear waste repository render neptunium tetravalent, which is assumed to be immobile in aqueous environment due to the low solubility solution of Np(IV). For tetravalent actinide nuclides, the most significant transport should occur via colloidal particles. This work demonstrates the formation of intrinsic neptunium dioxide nanocrystals and amorphous Np(IV) silica colloids under environmentally relevant conditions. The dissociation of the initial soluble Np(IV) complex (i.e. [Np(IV)(CO 3 ) 5 ] 6- ) induces the intrinsic formation of nanocrystalline NpO 2 in the solution phase. The resulting irregularly shaped nanocrystals with an average size of 4 nm exhibit a face-centered cubic (fcc), fluorite-type structure (space group Fm anti 3m). The NCs tend to agglomerate under ambient conditions due to the weakly charged hydrodynamic surface at neutral pH (zetapotential ζ ∝0 mV). The formation of micron-sized agglomerates, composed of nanocrystals of 2-5 nm in size, and the subsequent precipitation cause immobilization of the major amount of Np(IV) in the Np carbonate system. Agglomeration of NpO 2 nanocrystals in dependence on time was indicated by PCS and UV-vis absorption spectroscopy with the changes of baseline characteristics and absorption maximum at 742 nm. Hitherto, unknown polynuclear species as intermediate species of NpO 2 nanocrystal formation were isolated from solution and observed by HR-TEM. These polynuclear Np species appear as dimers, trimers and hexanuclear compounds in analogy with those reported for other actinides. Intrinsic formation of NpO 2

  3. Neuromorphic UAS Collision Avoidance

    Data.gov (United States)

    National Aeronautics and Space Administration — Collision avoidance for unmanned aerial systems (UAS) traveling at high relative speeds is a challenging task. It requires both the detection of a possible collision...

  4. Osteosarcoma induction by plutonium-239, americium-241 and neptunium-237 : the problem of deriving risk estimates for man

    International Nuclear Information System (INIS)

    Taylor, D.M.

    1988-01-01

    Spontaneous bone cancer (osteosarcoma) represents only about 0.3% of all human cancers, but is well known to be inducible in humans by internal contamination with radium-226 and radium-224. plutonium-239, americium-241 and neptunium-237 form, or will form, the principal long-lived alpha particle emitting components of high activity waste and burnt-up nuclear fuel elements. These three nuclides deposit extensively in human bone and although, fortunately, no case of a human osteosarcoma induced by any of these nuclides is known, evidence from animal studies suggests that all three are more effective than radium-226 in inducing osteosarcoma. The assumption that the ratio of the risk factors, the number of osteosarcoma expected per 10000 person/animal Gy, for radium-226 and any other bone-seeking alpha-emitter will be independent of animal species has formed the basis of all the important studies of the radiotoxicity of actinide nuclides in experimental animals. The aim of this communication is to review the risk factors which may be calculated from the various animal studies carried out over the last thirty years with plutonium-237, americium-241 and neptunium-237 and to consider the problems which may arise in extrapolating these risk factors to homo sapiens

  5. Preparation procedure and certification of uranous-uranic oxide and nitric acid solution of neptunium as standard specimens of plant

    International Nuclear Information System (INIS)

    Bulyanitsa, L.S.; Lipovskij, A.A.; Ryzhinskij, M.V.; Preobrazhensskaya, L.D.; Aleksandruk, V.M.; Alekseeva, N.A.; Gromova, E.A.; Solntseva, L.F.; Shereshevskaya, I.I.

    1981-01-01

    Two techniques of certification of standard specimens of plant (SSP) are considered. The first technique-comparison with initial SS-metallic uranium NBS-960 - is used for certification of uranium. protoxide-oxide. The mass part of the sum of analyzed impurities in prepared initial SS is (8.4+-0.8)x10 -3 %. For certification according to mass uranium part the method of gravimetric potentiometric titration with semiautomatic titrator is used; the mean quadratic deviation of the method is s=0.0002-0.0003, certified value of uranium mass part in SSP (taking account of the error of initial SS) is (84.80+-0.02)%. The second technigue - a simplified circular experiment - is used for certification of SSP-nitric acid solution of neptunium as to Np mass part. Coulometry at controlled potential and coulometry at controlled current and two variants of potentiometric titration are used as certification methods of analysis. Relative mean quadratic deviations of the methods are ssub(r)=0.0014-0.0023. When calculating total error of certified value of neptunium mass part constituents of both accidental and unremoved systematic errors of the methods were included. The final certification result of SSP is (5.707+-0.018)% [ru

  6. Method for Determination of Neptunium in Large-Sized Urine Samples Using Manganese Dioxide Coprecipitation and 242Pu as Yield Tracer

    DEFF Research Database (Denmark)

    Qiao, Jixin; Hou, Xiaolin; Roos, Per

    2013-01-01

    A novel method for bioassay of large volumes of human urine samples using manganese dioxide coprecipitation for preconcentration was developed for rapid determination of 237Np. 242Pu was utilized as a nonisotopic tracer to monitor the chemical yield of 237Np. A sequential injection extraction chr...... and rapid analysis of neptunium contamination level for emergency preparedness....

  7. Comparison of extraction chromatography and a procedure based on the molecular recognition method as separation methods in the determination of neptunium and plutonium radionuclides

    International Nuclear Information System (INIS)

    Strisovska, Jana; Galanda, Dusan; Drabova, Veronika; Kuruc, Jozef

    2012-01-01

    The potential of various types of sorbents for separation of radionuclides of plutonium and neptunium were examined. Extraction chromatography and a procedure based on the molecular recognition method were used for the separation. The suitability of the various sorbent types and brands for this purpose was determined. (orig.)

  8. Reactive Collision Avoidance Algorithm

    Science.gov (United States)

    Scharf, Daniel; Acikmese, Behcet; Ploen, Scott; Hadaegh, Fred

    2010-01-01

    The reactive collision avoidance (RCA) algorithm allows a spacecraft to find a fuel-optimal trajectory for avoiding an arbitrary number of colliding spacecraft in real time while accounting for acceleration limits. In addition to spacecraft, the technology can be used for vehicles that can accelerate in any direction, such as helicopters and submersibles. In contrast to existing, passive algorithms that simultaneously design trajectories for a cluster of vehicles working to achieve a common goal, RCA is implemented onboard spacecraft only when an imminent collision is detected, and then plans a collision avoidance maneuver for only that host vehicle, thus preventing a collision in an off-nominal situation for which passive algorithms cannot. An example scenario for such a situation might be when a spacecraft in the cluster is approaching another one, but enters safe mode and begins to drift. Functionally, the RCA detects colliding spacecraft, plans an evasion trajectory by solving the Evasion Trajectory Problem (ETP), and then recovers after the collision is avoided. A direct optimization approach was used to develop the algorithm so it can run in real time. In this innovation, a parameterized class of avoidance trajectories is specified, and then the optimal trajectory is found by searching over the parameters. The class of trajectories is selected as bang-off-bang as motivated by optimal control theory. That is, an avoiding spacecraft first applies full acceleration in a constant direction, then coasts, and finally applies full acceleration to stop. The parameter optimization problem can be solved offline and stored as a look-up table of values. Using a look-up table allows the algorithm to run in real time. Given a colliding spacecraft, the properties of the collision geometry serve as indices of the look-up table that gives the optimal trajectory. For multiple colliding spacecraft, the set of trajectories that avoid all spacecraft is rapidly searched on

  9. Redox stability of neptunium(V) in the presence of humic substances of varying functionality

    Energy Technology Data Exchange (ETDEWEB)

    Schmeide, K.; Geipel, G.; Bernhard, G. [Forschungszentrum Rossendorf e.V., Institute of Radiochemistry, P.O. Box 510 119, D-01314 Dresden (Germany)

    2005-07-01

    be stabilized in lower oxidation states, e.g. in complexation and sorption studies. [1] Sachs, S., Schmeide, K., Brendler, V., Krepelova, A., Mibus, J., Geipel, G., Heise, K.H., Bernhard, G.: Investigation of the Complexation and the Migration of Actinides and Nonradioactive Substances with Humic Acids under Geo-genic Conditions. Complexation of Humic Acids with Actinides in the Oxidation State IV Th, U, Np. FZR-399, Wissenschaftlich- Technische Berichte, Forschungszentrum Rossendorf, Dresden 2004. [2] Schmeide, K., Geipel, G., Bernhard, G.: Study of the Neptunium(V) Reduction by Various Natural and Synthetic Humic Substances. In: FZKA 7070, Wissenschaftliche Berichte (G. Buckau, ed.). Forschungszentrum Karlsruhe, Karlsruhe 2005, in press. (authors)

  10. Surface complexation of neptunium (V) onto whole cells and cell componets of Shewanella alga

    Energy Technology Data Exchange (ETDEWEB)

    Reed, Donald Timothy [Los Alamos National Laboratory; Deo, Randhir P [ASU; Rittmann, Bruce E [ASU; Songkasiri, Warinthorn [UNAFFILIATED

    2008-01-01

    We systematically quantified surface complexation of neptunium(V) onto whole cells of Shewanella alga strain BrY and onto cell wall and extracellular polymeric substances (EPS) of S. alga. We first performed acid and base titrations and used the mathematical model FITEQL with constant-capacitance surface-complexation to determine the concentrations and deprotonation constants of specific surface functional groups. Deprotonation constants most likely corresponded to a carboxyl site associated with amino acids (pK{sub a} {approx} 2.4), a carboxyl group not associated with amino acids (pK{sub a} {approx} 5), a phosphoryl site (pK{sub a} {approx} 7.2), and an amine site (pK{sub a} > 10). We then carried out batch sorption experiments with Np(V) and each of the S. alga components at different pHs. Results show that solution pH influenced the speciation of Np(V) and each of the surface functional groups. We used the speciation sub-model of the biogeochemical model CCBATCH to compute the stability constants for Np(V) complexation to each surface functional group. The stability constants were similar for each functional group on S. alga bacterial whole cells, cell walls, and EPS, and they explain the complicated sorption patterns when they are combined with the aqueous-phase speciation of Np(V). For pH < 8, NpO{sub 2}{sup +} was the dominant form of Np(V), and its log K values for the low-pK{sub a} carboxyl, other carboxyl, and phosphoryl groups were 1.75, 1.75, and 2.5 to 3.1, respectively. For pH greater than 8, the key surface ligand was amine >XNH3+, which complexed with NpO{sub 2}(CO{sub 3}){sub 3}{sup 5-}. The log K for NpO{sub 2}(CO{sub 3}){sub 3}{sup 5-} complexed onto the amine groups was 3.1 to 3.6. All of the log K values are similar to those of Np(V) complexes with aqueous carboxyl and N-containing carboxyl ligands. These results point towards the important role of surface complexation in defining key actinide-microbiological interactions in the subsurface.

  11. Avoiding the Flu

    Science.gov (United States)

    ... of this page please turn Javascript on. Feature: Flu Avoiding the Flu Past Issues / Fall 2009 Table of Contents Children ... should still get the 2009 H1N1 vaccine. H1N1 Flu: Who Should Be Vaccinated First The Centers for ...

  12. Helping Students Avoid Plagiarism.

    Science.gov (United States)

    Wilhoit, Stephen

    1994-01-01

    Discusses how and why college students commit plagiarism, suggesting techniques that instructors can use to help student avoid plagiarism. Instructors should define and discuss plagiarism thoroughly; discuss hypothetical cases; review the conventions of quoting and documenting material; require multiple drafts of essays; and offer responses…

  13. Human pathogen avoidance adaptations

    NARCIS (Netherlands)

    Tybur, J.M.; Lieberman, D.

    2016-01-01

    Over the past few decades, researchers have become increasingly interested in the adaptations guiding the avoidance of disease-causing organisms. Here we discuss the latest developments in this area, including a recently developed information-processing model of the adaptations underlying pathogen

  14. Synthesis of a Cementitious Material Nanocement Using Bottom-Up Nanotechnology Concept: An Alternative Approach to Avoid CO2 Emission during Production of Cement

    Directory of Open Access Journals (Sweden)

    Byung Wan Jo

    2014-01-01

    Full Text Available The world’s increasing need is to develop smart and sustainable construction material, which will generate minimal climate changing gas during their production. The bottom-up nanotechnology has established itself as a promising alternative technique for the production of the cementitious material. The present investigation deals with the chemical synthesis of cementitious material using nanosilica, sodium aluminate, sodium hydroxide, and calcium nitrate as reacting phases. The characteristic properties of the chemically synthesized nanocement were verified by the chemical composition analysis, setting time measurement, particle size distribution, fineness analysis, and SEM and XRD analyses. Finally, the performance of the nanocement was ensured by the fabrication and characterization of the nanocement based mortar. Comparing the results with the commercially available cement product, it is demonstrated that the chemically synthesized nanocement not only shows better physical and mechanical performance, but also brings several encouraging impacts to the society, including the reduction of CO2 emission and the development of sustainable construction material. A plausible reaction scheme has been proposed to explain the synthesis and the overall performances of the nanocement.

  15. Neptunium redox behavior and sorption onto goethite and hematite in the presence of humic acids with different hydroquinone content

    International Nuclear Information System (INIS)

    Khasanova, A.B.; Kalmykov, St.N.; Perminova, I.V.; Clark, S.B.

    2007-01-01

    The effect of humic acids (HA) on neptunium redox behavior and sorption onto hematite, α-Fe 2 O 3 , and goethite, α-FeOOH, colloids was established in batch sorption experiments that were carried out in broad pH interval. The sorption isotherms were provided for two samples of HA: commercial sample of leonardite humic acid and its hydroquinone-enriched derivative obtained using formaldehyde copolycondensation. The distribution of Np fitted the distribution of hydroquinone-enriched HA at low pH values in case of both solids while the influence of parent HA on Np sorption was negligible. This is due to Np(V) reduction upon interaction with hydroquinone-enriched derivative having higher reducing capacity compared to the parent HA. The order of components addition was found to be significant for Np retention

  16. The incorporation of neptunium and plutonium in thorutite (ThTi{sub 2}O{sub 6})

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yingjie, E-mail: yzx@ansto.gov.au; Gregg, Daniel J.; Lumpkin, Gregory R.; Begg, Bruce D.; Jovanovic, Miodrag

    2013-12-25

    Highlights: •The incorporation of neptunium (Np) and plutonium (Pu) in thorutite (ThTi{sub 2}O{sub 6}) has been studied. •The effect of Np/Pu doping on the unit cell parameter changes has been discussed from the structure point of view. •The effect of Y as charge compensator to encourage the formation of higher valences of Np and Pu has been explored. •The resulting Np/Pu doped thorutite samples have been characterised by using XRD, SEM and DRS. -- Abstract: The incorporation of neptunium (Np) and plutonium (Pu) into the brannerite structured lattice was studied using thorutite (ThTi{sub 2}O{sub 6}) as host lattice and sintering in air. The uncompensated Np and Pu doped samples and the low Y-charge compensated Np and Pu doped samples showed main phases as designed together with trace amounts of rutile. Those samples with larger amounts of Y produced yttrium pyrochlores as an additional minor phase. XRD analyses reveal anisotropic changes of the cell parameters; the a-parameter contracts while b- and c-parameters expand with mean cationic radius. This is in reasonable agreement with previous experimental data on ThTi{sub 2}O{sub 6} and Ce{sub 0.975}Ti{sub 2}O{sub 5.95}. Attempts to form Np or Pu valences >4+ by adding Y as a charge compensator were unsuccessful, suggesting that tetravalent Np and Pu ions are favoured in air-fired thorutite.

  17. Computer modelling of the chemical speciation of caesium, uranium(VI) and neptunium(V) in human duodenal fluids under fasting conditions

    International Nuclear Information System (INIS)

    Jones, P.W.; Taylor, D.M.; Webb, L.M.; Williams, D.R.

    2002-01-01

    A model simulating the human duodenal contents under physiologically realistic, fasting conditions was developed using the joint expert speciation system (JESS) computer program and database and used to investigate the chemical speciation of caesium, uranium(VI) and neptunium(V). Over the pH range 5.0-9.0, and the concentration range 5x10 -15 -5x10 -5 mol dm -3 , caesium was predicted to occur predominantly as the absorbable free monovalent cation Cs + (∼95%) with species such as CsHPO 4 - and CsCl representing the remainder. The presence or absence of sulphate at 2.1x10 -3 mol dm -3 did not influence the predicted speciation. Uranium was predicted to be present entirely as a soluble, highly charged species, both in the absence and in the presence of sulphate. Between pH 5.0 and ∼6.5 the UO 2 H 2 (PO 4 ) 2 2- predominated, above this pH carbonate species, either UO 2 (CO 3 ) 4 6- or, possibly, UO 2 (CO 3 ) 5 8- . At pH 8.0, and in the presence of sulphate, neptunium(V) was predicted to exist solely as the tetrasulphate species, whilst in the absence of sulphate, an array of negatively charged soluble carbonate species predominated. Studies over the pH range 5.0-9.0 predicted the formation of a spectrum of negatively charged carbonate and phosphate species, ∼40% of the total neptunium was predicted to be present as the electrically net-neutral species NpO 2 HCO 3 at pH6.0, ∼20% at pH 7.0, ∼10% at pH 7.5 and ∼1% at pH 8.0. The observed speciation patterns of uranium and neptunium did not change over the concentration range 5x10 -15 -5x10 -5 mol dm -3 and no solid species were predicted to occur under the conditions simulated. Whether the predicted electrically net-neutral neptunium species or the uranium pentacarbonate species do actually occur under true physiological conditions remains to be established. The observed speciation patterns for caesium and uranium are consistent with the observed absorption of these elements by humans; however, the

  18. Comparison of various chemical processes for avoidance of generation of radio active solid waste in UO{sub 2} powder production process

    Energy Technology Data Exchange (ETDEWEB)

    Visweswara Rao, R.V.R.L.; Babaji, P.; Sairam, S.; Meena, R.; Hemantharao, G.V.S.; Jayaraj, R.N. [Nuclear Fuel Complex, Dept. of Atomic Energy, Hyderabad (India)

    2008-07-01

    The Uranium Di-Oxide (UO{sub 2}) powder production process involves dissolution of yellow cake (uranium concentrate) in commercial grade nitric acid followed by solvent extraction process to obtain nuclear grade Uranyl Nitrate Solution(UNS). The UNS is initially precipitated with ammonia to produce Ammonium Di-Uranate (ADU) and subsequently converted to UO{sub 2} powder through a series of thermal treatment steps viz. calcination, reduction and stabilization. The Uranyl Nitrate Raffinate (UNR) generated in the purification step above, contains residual uranium, due to which its direct disposal is not permissible. The effluent is therefore neutralized with caustic lye and the resultant slurry is filtered over a pre-coat drum filter. The uranium thus gets fixed in the solid form, Uranyl Nitrate Raffinate Cake (UNRC) and the filtrate is disposed off, after ensuring that it meets the disposal criteria of 1 Bq/gm of solid. The uranium bearing solid waste is packed in 200 litre polythene lined MS drums and transported to uranium mill for further processing. This UNR treatment process is manpower intensive, requires large storage space, and involves material handling work, transportation etc. In order to reduce/eliminate generation of UNRC, several new chemical processes were developed and studied in detail. An attempt is made to compare these different processes and the details are presented in this paper. (author)

  19. Avoidable waste management costs

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, K.; Burns, M.; Priebe, S.; Robinson, P.

    1995-01-01

    This report describes the activity based costing method used to acquire variable (volume dependent or avoidable) waste management cost data for routine operations at Department of Energy (DOE) facilities. Waste volumes from environmental restoration, facility stabilization activities, and legacy waste were specifically excluded from this effort. A core team consisting of Idaho National Engineering Laboratory, Los Alamos National Laboratory, Rocky Flats Environmental Technology Site, and Oak Ridge Reservation developed and piloted the methodology, which can be used to determine avoidable waste management costs. The method developed to gather information was based on activity based costing, which is a common industrial engineering technique. Sites submitted separate flow diagrams that showed the progression of work from activity to activity for each waste type or treatability group. Each activity on a flow diagram was described in a narrative, which detailed the scope of the activity. Labor and material costs based on a unit quantity of waste being processed were then summed to generate a total cost for that flow diagram. Cross-complex values were calculated by determining a weighted average for each waste type or treatability group based on the volume generated. This study will provide DOE and contractors with a better understanding of waste management processes and their associated costs. Other potential benefits include providing cost data for sites to perform consistent cost/benefit analysis of waste minimization and pollution prevention (WMIN/PP) options identified during pollution prevention opportunity assessments and providing a means for prioritizing and allocating limited resources for WMIN/PP.

  20. Avoidable waste management costs

    International Nuclear Information System (INIS)

    Hsu, K.; Burns, M.; Priebe, S.; Robinson, P.

    1995-01-01

    This report describes the activity based costing method used to acquire variable (volume dependent or avoidable) waste management cost data for routine operations at Department of Energy (DOE) facilities. Waste volumes from environmental restoration, facility stabilization activities, and legacy waste were specifically excluded from this effort. A core team consisting of Idaho National Engineering Laboratory, Los Alamos National Laboratory, Rocky Flats Environmental Technology Site, and Oak Ridge Reservation developed and piloted the methodology, which can be used to determine avoidable waste management costs. The method developed to gather information was based on activity based costing, which is a common industrial engineering technique. Sites submitted separate flow diagrams that showed the progression of work from activity to activity for each waste type or treatability group. Each activity on a flow diagram was described in a narrative, which detailed the scope of the activity. Labor and material costs based on a unit quantity of waste being processed were then summed to generate a total cost for that flow diagram. Cross-complex values were calculated by determining a weighted average for each waste type or treatability group based on the volume generated. This study will provide DOE and contractors with a better understanding of waste management processes and their associated costs. Other potential benefits include providing cost data for sites to perform consistent cost/benefit analysis of waste minimization and pollution prevention (WMIN/PP) options identified during pollution prevention opportunity assessments and providing a means for prioritizing and allocating limited resources for WMIN/PP

  1. Mutation avoidance and DNA repair proficiency in Ustilago maydis are differentially lost with progressive truncation of the REC1 gene product

    Energy Technology Data Exchange (ETDEWEB)

    Onel, K.; Thelen, M.P.; Ferguson, D.O.; Bennett, R.L.; Holloman, W.K. [Cornell Univ. Medical College, NY, NY (United States)

    1995-10-01

    The REC1 gene of Ustilago maydis has an uninterrupted open reading frame, predicted from the genomic sequence to encode a protein of 522 amino acid residues. Nevertheless, an intron is present, and functional activity of the gene in mitotic cells requires an RNA processing event to remove the intron. This results in a change in reading frame and production of a protein of 463 amino acid residues. The 3{prime}{r_arrow}5{prime} exonuclease activity of proteins derived form the REC1 genomic open reading frame, the intronless open reading frame, and several mutants was investigated. The mutants included a series of deletions constructed by removing restriction fragments at the 3{prime} end of the cloned REC1 gene and a set of mutant alleles previously isolated in screens for radiation sensitivity. The results indicated that elimination of the C-terminal third of the protein did not result in a serious reduction in 3{prime}{r_arrow}5{prime} exonuclease activity, but deletion into the midsection caused a severe loss of activity. The biological activity of the rec1-1 allele, which encodes a truncated polypeptide with full 3{prime}{r_arrow}5{prime} exonuclease activity, and the rec1-5 allele, which encodes a more severely truncated polypeptide with no exonuclease activity, was investigated. The two mutants were equally sensitive to the lethal effect of UV light, but the spontaneous mutation rate was elevated 10-fold over the wild-type rate in the rec1-1 mutant and 100-fold in the rec1-5 mutant. The elevated spontaneous mutation rate correlated with the ablation of exonuclease activity, but the radiation sensitivity did not. These results indicate that the C-terminal portion of the Rec1 protein is not essential for exonuclease activity but is crucial in the role of REC1 in DNA damage repair. 49 refs., 3 figs., 1 tab.

  2. Separation by sequential chromatography of americium, plutonium and neptunium elements: application to the study of trans-uranian elements migration in a European lacustrine system

    International Nuclear Information System (INIS)

    Michel, H.

    1999-01-01

    The nuclear tests carried out in the atmosphere in the Sixties, the accidents and in particular that to the power station of Chernobyl in 1986, were at the origin of the dispersion of a significant quantity of transuranic elements and fission products. The study of a lake system, such that of the Blelham Tarn in Great Britain, presented in this memory, can bring interesting answers to the problems of management of the environment. The determination of the radionuclides in sediment cores made it possible not only to establish the history of the depositions and consequently the origin of the radionuclides, but also to evaluate the various transfers which took place according to the parameters of the site and the properties of the elements. The studied transuranic elements are plutonium 238, 239-240, americium 241 and neptunium 237. Alpha emitting radionuclides, their determination requires complex radiochemical separations. A method was worked out to successively separate the three radioelements by using a same chromatographic column. Cesium 137 is the studied fission product, its determination is done by direct Gamma spectrometry. Lead 210, natural radionuclide, whose atmospheric flow can be supposed constant. makes it possible to obtain a chronology of the various events. The detailed vertical study of sediment cores showed that the accumulation mode of the studied elements is the same one and that the methods of dating converge. The cesium, more mobile than transuranic elements in the atmosphere, was detected in the 1963 and 1986 fallout whereas an activity out of transuranic elements appears only for the 1963 fallout. The activity of the 1963 cesium fallout is of the same order of magnitude as that of 1986. The calculation of the diffusion coefficients of the elements in the sediments shows an increased migration of cesium compared to transuranic elements. An inventory on the whole of the lake made it possible to note that the atmospheric fallout constitute the

  3. Food Waste Avoidance Actions in Food Retailing

    DEFF Research Database (Denmark)

    Kulikovskaja, Viktorija; Aschemann-Witzel, Jessica

    2017-01-01

    Food waste occurs throughout the entire food supply chain, from production to consumption of food in households. Retailers are in a unique position to contribute to food waste avoidance, not only by minimizing the amount of waste in their distribution channels but also by influencing consumer...... attitudes and behaviors. This explorative study aims to identify which food waste avoidance actions are conducted by retailers in Denmark, to which extent, and how they vary across food categories and supermarket chain. Based on an analysis of secondary and empirical data collected via observations...... at retail stores, the authors identify 22 food waste avoidance actions in Danish retail. The results provide new insights into food waste avoidance in retail. Based on the findings, suggestions for further research directions are developed that should serve to identify the most efficient customer targeted...

  4. Use of radioanalytical methods for determination of uranium, neptunium, plutonium, americium and curium isotopes in radioactive wastes; Utilizacao de metodos radioanaliticos para a determinacao de isotopos de uranio, plutonio, americio e curio em rejeitos radioativos

    Energy Technology Data Exchange (ETDEWEB)

    Geraldo, Bianca

    2012-07-01

    Activated charcoal is a common type of radioactive waste that contains high concentrations of fission and activation products. The management of this waste includes its characterization aiming the determination and quantification of the specific radionuclides including those known as Difficult-to-Measure Radionuclides (RDM). The analysis of the RDM's generally involves complex radiochemical analysis for purification and separation of the radionuclides, which are expensive and time-consuming. The objective of this work was to define a methodology for sequential analysis of the isotopes of uranium, neptunium, plutonium, americium and curium present in a type of radioactive waste, evaluating chemical yield, analysis of time spent, amount of secondary waste generated and cost. Three methodologies were compared and validated that employ ion exchange (TI + EC), extraction chromatography (EC) and extraction with polymers (ECP). The waste chosen was the activated charcoal from the purification system of primary circuit water cooling the reactor IEA-R1. The charcoal samples were dissolved by acid digestion followed by purification and separation of isotopes with ion exchange resins, extraction and chromatographic extraction polymers. Isotopes were analyzed on an alpha spectrometer, equipped with surface barrier detectors. The chemical yields were satisfactory for the methods TI + EC and EC. ECP method was comparable with those methods only for uranium. Statistical analysis as well the analysis of time spent, amount of secondary waste generated and cost revealed that EC method is the most effective for identifying and quantifying U, Np, Pu, Am and Cm present in charcoal. (author)

  5. Application of simplified desorption method to sorption study. (2) Sorption of neptunium (V) on montmorillonite-based mixtures

    International Nuclear Information System (INIS)

    Kozai, Naofumi; Ohnuki, Toshihiko

    2013-01-01

    To elucidate the sorption behaviors of radionuclides in multi-mineral systems and the mutual effects of minerals on the sorption, this paper carried out the sorption and desorption experiments of neptunium(V) on montmorillonite-based two-mineral mixtures. The Np sorbed on montmorillonite at pH from 4 to 8 was desorbed with 1M KCl solutions, indicating that the sorption was cation exchange. The Np sorbed on apatite and calcite was nondesorbable with 1M KCl solutions, which is in harmony with the knowledge that Np forms strong complexes with the phosphate groups of apatite and the carbonate groups of calcite. This study utilized these clear distinguishes of the desorption behaviors for examining the two-mineral systems. In montmorillonite-apatite mixtures, the sorption on the montmorillonite was decreased and Np was accumulated on the apatite. In montmorillonite-calcite mixtures, the sorption on the montmorillonite was decreased due to the interference by the calcium and carbonate ions dissolved from calcite while no accumulation of Np to calcite was observed. (author)

  6. The aqueous solubility and speciation analysis for uranium, neptunium and selenium by the geochemical code(EQ3/6)

    International Nuclear Information System (INIS)

    Takeda, Seiji; Shima, Shigeki; Kimura, Hideo; Matsuzuru, Hideo

    1995-11-01

    The geochemical condition of a geologic disposal system of HLW controls the solubility and physicochemical forms of dominant aqueous species for elements, which are one of essential information required for safety assessment. Based on the measured compositions of groundwater, the compositions of groundwater in the disposal system were calculated. The solubility and speciation analyses for the polyvalent elements, uranium, neptunium, and selenium, were performed by the geochemical code EQ3/6. The results obtained were compared with the data appeared in the literatures on the solubilities and speciations. The geochemical behaviors of the elements with respect to the solubility and speciation could quantitatively be elucidated for the compositions of the interstitial waters in an engineered barrier and ground water in a natural barrier. In the pH range of neutral to alkali, the solubilities of U and Np tend to increase with an increase of the carbonate concentration in groundwater. This carbonate concentration dependence of the solubility was also estimated. In the engineered barrier the predominant aqueous species were specified, and in the natural barrier the change of aqueous species was also predicted while the chemical compositions changed from the reducing to oxidizing conditions. The dominant aqueous species for the elements, which migrate in and through the disposal system, were determined by the speciation analysis. (author)

  7. Potential for radionuclide immobilization in the EBS/NFE: solubility limiting phases for neptunium, plutonium, and uranium

    Energy Technology Data Exchange (ETDEWEB)

    Rard, J. A., LLNL

    1997-10-01

    Retardation and dispersion in the far field of radionuclides released from the engineered barrier system/near field environment (EBS/NFE) may not be sufficient to prevent regulatory limits being exceeded at the accessible environment. Hence, a greater emphasis must be placed on retardation and/or immobilization of radionuclides in the EBS/NFE. The present document represents a survey of radionuclide-bearing solid phases that could potentially form in the EBS/NFE and immobilize radionuclides released from the waste package and significantly reduce the source term. A detailed literature search was undertaken for experimental solubilities of the oxides, hydroxides, and various salts of neptunium, plutonium, and uranium in aqueous solutions as functions of pH, temperature, and the concentrations of added electrolytes. Numerous solubility studies and reviews were identified and copies of most of the articles were acquired. However, this project was only two months in duration, and copies of some the identified solubility studies could not be obtained at short notice. The results of this survey are intended to be used to assess whether a more detailed study of identified low- solubility phase(s) is warranted, and not as a data base suitable for predicting radionuclide solubility. The results of this survey may also prove useful in a preliminary evaluation of the efficacy of incorporating chemical additives to the EBS/NFE that will enhance radionuclide immobilization.

  8. Electrochemical and spectroscopic studies of neptunium in the aluminum chloride-1-n-butylpyridinium chloride melt at 400C

    International Nuclear Information System (INIS)

    Schoebrechts, J.P.; Gilbert, B.

    1985-01-01

    The chemistry of neptunium in acidic and basic AlCl 3 -1-n-butylpyridinium chloride melts at 40 0 C has been investigated by means of electrochemical and spectral techniques. In acidic as well as in basic melts, the reduction of Np(IV) to Np(III) at glassy-carbon electrodes is quasi-reversible. Indirect measurements of the formal potential and spectroscopic results on the Np(IV)-Np(III) system as a function of the acidity indicate that Np(III) and Np(IV) exist as NpCl 6 3- and NpCl 6 2- and solvated Np 3+ and NpCl/sub x//sup (4-x)+/ (with 3 greater than or equal to x greater than or equal to 1), respectively, in basic and acidic melts. The apparent rate constant K 0 ' has been measured on the basic and acidic sites. It depends on the melt acidity only in the latter melts. The Nugent linearization method has been applied to the standard potentials of Np(IV)-Np(III) and U(IV)-U(III) in 2:1 melts. A comparison with the results obtained from other room-temperature solvents shows, as already found with lanthanides, that the acidic melt is a very weak solvating medium

  9. Avoiding lock-in

    DEFF Research Database (Denmark)

    Henriksen, Ingrid

    1999-01-01

    The paper investigates the initial phase of the cooperative organisation of agricultural processing firms in Denmark. It argues that the variations observed can be explained within the framework of the theory of industrial organisation. The focus is on the success of cooperative creameries. In 19...... of gathering information and of preserving and transporting a perishable product, were ideally suited to overcome the problems of potential lock-in and of asymmetric information...

  10. Concept and experimental studies on fuel and target for minor actinides and fission products transmutation

    Energy Technology Data Exchange (ETDEWEB)

    Prunier, C; Guerin, Y [CEA Centre d` Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. d` Etudes des Combustibles; Salvatores, M [CEA Centre d` Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Direction des Reacteurs Nucleaires; Zaetta, A [CEA Centre d` Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. d` Etudes des Reacteurs

    1994-12-31

    High activity long-lived radionuclides in nuclear wastes, namely minor actinides (americium and neptunium) are in large amount generated by current nuclear reactive. The destruction of these radionuclides is a part of the French SPIN (Partitioning and Burning) program consistent with the determination to send a minimum amount of harmful products for final storage. Transmutation concepts are defined for neptunium and americium taking into account fuel cycle strategies. Neptunium destruction does not pose any major problems. It`s a by-product of uranium consumption, as plutonium and in despite of a slight gamma activity due to the protactinium 233 it`s quite easy to handle. Diluting neptunium in the mixed oxide fuels (MOX) should not be an obstacle for fabrication, in-pile behaviour and reprocessing either. Consequently we make the proposal of homogeneous mode of neptunium in MOX which should be soon explored in the experimental OSIRIS reactor and in the Phenix and Superphenix reactors. The analysis is more complex for the multi isotope americium. Its destruction is difficult because of gamma radioactivity which complicates fabrication. Experiments in Phenix and calculation showed that Phenix reactor offers a good potential for americium incineration, but similar data do not exist for PWR. It will remain a well known difficulty for fabrication and reprocessing. In this case we have to put a real new face to the fabrication flow-sheet of americium compounds and we propose to develop the heterogeneous mode. Targets choice are defined in term of: -safety, considering fuel reaction with cladding and water sodium, -transmutation rate, limited by target behaviour, in FR`s (Phenix), PWR`s (OSIRIS) and HFR (Petten), -reprocessing, checking the solubility of such targets by Purex process. So, at the beginning of our program the account has been on improving fuel and targets properties related to safety and fuel cycle. (authors). 4 figs.

  11. Determinants of Aggressive Tax Avoidance

    OpenAIRE

    Herbert, Tanja

    2015-01-01

    This thesis consists of three essays examining determinants of aggressive tax avoidance. The first essay “Measuring the Aggressive Part of International Tax Avoidance”, co-authored with Prof. Dr. Michael Overesch, proposes a new measure that isolates the additional or even aggressive part in international tax avoidance and analyzes the determinants of aggressive tax avoidance of multinational enterprises. The second essay “Capital Injections and Aggressive Tax Planning - Can Banks Have It All...

  12. Predictors of avoiding medical care and reasons for avoidance behavior.

    Science.gov (United States)

    Kannan, Viji Diane; Veazie, Peter J

    2014-04-01

    Delayed medical care has negative health and economic consequences; interventions have focused on appraising symptoms, with limited success in reducing delay. To identify predictors of care avoidance and reasons for avoiding care. Using the Health Information National Trends Survey (2007), we conducted logistic regressions to identify predictors of avoiding medical visits deemed necessary by the respondents; and, we then conducted similar analyses on reasons given for avoidance behavior. Independent variables included geographic, demographic, socioeconomic, personal health, health behavior, health care system, and cognitive characteristics. Approximately one third of adults avoided doctor visits they had deemed necessary. Although unadjusted associations existed, avoiding needed care was not independently associated with geographic, demographic, and socioeconomic characteristics. Avoidance behavior is characterized by low health self-efficacy, less experience with both quality care and getting help with uncertainty about health, having your feelings attended to by your provider, no usual source of care, negative affect, smoking daily, and fatalistic attitude toward cancer. Reasons elicited for avoidance include preference for self-care or alternative care, dislike or distrust of doctors, fear or dislike of medical treatments, time, and money; respondents also endorsed discomfort with body examinations, fear of having a serious illness, and thoughts of dying. Distinct predictors distinguish each of these reasons. Interventions to reduce patient delay could be improved by addressing the health-related behavioral, belief, experiential, and emotional traits associated with delay. Attention should also be directed toward the interpersonal communications between patients and providers.

  13. Stimulus conflict triggers behavioral avoidance.

    Science.gov (United States)

    Dignath, David; Eder, Andreas B

    2015-12-01

    According to a recent extension of the conflict-monitoring theory, conflict between two competing response tendencies is registered as an aversive event and triggers a motivation to avoid the source of conflict. In the present study, we tested this assumption. Over five experiments, we examined whether conflict is associated with an avoidance motivation and whether stimulus conflict or response conflict triggers an avoidance tendency. Participants first performed a color Stroop task. In a subsequent motivation test, participants responded to Stroop stimuli with approach- and avoidance-related lever movements. These results showed that Stroop-conflict stimuli increased the frequency of avoidance responses in a free-choice motivation test, and also increased the speed of avoidance relative to approach responses in a forced-choice test. High and low proportions of response conflict in the Stroop task had no effect on avoidance in the motivation test. Avoidance of conflict was, however, obtained even with new conflict stimuli that had not been presented before in a Stroop task, and when the Stroop task was replaced with an unrelated filler task. Taken together, these results suggest that stimulus conflict is sufficient to trigger avoidance.

  14. Healthcare avoidance: a critical review.

    Science.gov (United States)

    Byrne, Sharon K

    2008-01-01

    The purpose of this study is to provide a critical review and synthesis of theoretical and research literature documenting the impact of avoidance on healthcare behaviors, identify the factors that influence healthcare avoidance and delay in the adult population, and propose a direction for future research. The Theory of Reasoned Action, Theory of Planned Behavior, Theory of Care-Seeking Behavior, the Transtheoretical Model, and the Behavioral Model of Health Services Use/Utilization are utilized to elaborate on the context within which individual intention to engage in healthcare behaviors occurs. Research literature on the concept of healthcare avoidance obtained by using computerized searches of CINAHL, MEDLINE, PSYCH INFO, and HAPI databases, from 1995 to 2007, were reviewed. Studies were organized by professional disciplines. Healthcare avoidance is a common and highly variable experience. Multiple administrative, demographic, personal, and provider factors are related to healthcare avoidance, for example, distrust of providers and/or the science community, health beliefs, insurance status, or socioeconomic/income level. Although the concept is recognized by multiple disciplines, limited research studies address its impact on healthcare decision making. More systematic research is needed to determine correlates of healthcare avoidance. Such studies will help investigators identify patients at risk for avoidant behaviors and provide the basis for health-promoting interventions. Methodological challenges include identification of characteristics of individuals and environments that hinder healthcare behaviors, as well as, the complexity of measuring healthcare avoidance. Studies need to systematically explore the influence of avoidance behaviors on specific healthcare populations at risk.

  15. An avoidance layer in hierarchical process control

    International Nuclear Information System (INIS)

    De Callatay, A.

    1994-01-01

    A project of layered software architecture is proposed: a safety-critical real-time non-stop simple kernel system includes a layer avoiding threatening actions from operators or programs in other control systems. Complex process-control applications (such as fuzzy systems) are useful for the smooth operation of the system, optimum productivity, efficient diagnostics, and safe management of degraded modes of operation. Defects in these complex process-control applications do not have an impact on safety if their commands have first to be accepted by a safety-critical module. The development, testing, and certification of complex applications computed in the outside layers can be made simpler and less expensive than for those in the kernel. Avoidance systems use rule-base systems having negative fuzzy conditions and actions. Animal and human behaviour cannot be explained without active avoidance

  16. Avoiding powerless future

    International Nuclear Information System (INIS)

    Lowe, I.

    1999-01-01

    Except for oil, energy resources are plentiful. The author argued that we should be planning now for the inevitable changes to our transport system after the peak of world oil production, variously estimated as between about 2005 and 2020. More generally, heavy use of coal and oil is causing a wide range of environmental problems. The world's increasing use of these fossil fuels is now recognised, even by the Australian government, to be changing the global climate. Growing concern about the likely consequences led to the adoption of the Kyoto agreement, which commits all major fossil fuel-using OECD nations except Australia to reduce gas emissions. Technologies such as solar, wind and biomass energy systems are seen as cleaner and more worthy of subsidy than coal, oil and shale, all of which receive government subsidies and tax concessions

  17. Radionuclide sorption in Yucca Mountain tuffs with J-13 well water: Neptunium, uranium, and plutonium. Yucca Mountain site characterization program milestone 3338

    International Nuclear Information System (INIS)

    Triay, I.R.; Cotter, C.R.; Kraus, S.M.; Huddleston, M.H.

    1996-08-01

    We studied the retardation of actinides (neptunium, uranium, and plutonium) by sorption as a function of radionuclide concentration in water from Well J-13 and of tuffs from Yucca Mountain. Three major tuff types were examined: devitrified, vitric, and zeolitic. To identify the sorbing minerals in the tuffs, we conducted batch sorption experiments with pure mineral separates. These experiments were performed with water from Well J-13 (a sodium bicarbonate groundwater) under oxidizing conditions in the pH range from 7 to 8.5. The results indicate that all actinides studied sorb strongly to synthetic hematite and also that Np(V) and U(VI) do not sorb appreciably to devitrified or vitric tuffs, albite, or quartz. The sorption of neptunium onto clinoptilolite-rich tuffs and pure clinoptilolite can be fitted with a sorption distribution coefficient in the concentration range from 1 X 10 -7 to 3 X 10 -5 M. The sorption of uranium onto clinoptilolite-rich tuffs and pure clinoptilolite is not linear in the concentration range from 8 X 10 -8 to 1 X 10 -4 M, and it can be fitted with nonlinear isotherm models (such as the Langmuir or the Freundlich Isotherms). The sorption of neptunium and uranium onto clinoptilolite in J-13 well water increases with decreasing pH in the range from 7 to 8.5. The sorption of plutonium (initially in the Pu(V) oxidation state) onto tuffs and pure mineral separates in J-13 well water at pH 7 is significant. Plutonium sorption decreases as a function of tuff type in the order: zeolitic > vitric > devitrified; and as a function of mineralogy in the order: hematite > clinoptilolite > albite > quartz

  18. Conflict Avoidance and University Management.

    Science.gov (United States)

    Tagliacozzo, Daisy M.

    The conditions that intensify conflict avoidance by the central administration in making strategic decisions, and the consequences of such avoidance for the management of college affairs, are discussed. The implication of an emerging decision-making style for adapting the organization to changing environments is also considered. Some of the…

  19. Cigarette tax avoidance and evasion.

    Science.gov (United States)

    Stehr, Mark

    2005-03-01

    Variation in state cigarette taxes provides incentives for tax avoidance through smuggling, legal border crossing to low tax jurisdictions, or Internet purchasing. When taxes rise, tax paid sales of cigarettes will decline both because consumption will decrease and because tax avoidance will increase. The key innovation of this paper is to compare cigarette sales data to cigarette consumption data from the Behavioral Risk Factor Surveillance System (BRFSS). I show that after subtracting percent changes in consumption, residual percent changes in sales are associated with state cigarette tax changes implying the existence of tax avoidance. I estimate that the tax avoidance response to tax changes is at least twice the consumption response and that tax avoidance accounted for up to 9.6% of sales between 1985 and 2001. Because of the increase in tax avoidance, tax paid sales data understate the level of smoking and overstate the drop in smoking. I also find that the level of legal border crossing was very low relative to other forms of tax avoidance. If states have strong preferences for smoking control, they must pair high cigarette taxes with effective policies to curb smuggling and other forms of tax avoidance or employ alternative policies such as counter-advertising and smoking restrictions.

  20. Assessment of Neptunium, Americium, and Curium in the Savannah River Site Environment

    International Nuclear Information System (INIS)

    Carlton, W.H.

    1997-01-01

    A series of documents has been published in which the impact of various radionuclides released to the environment by Savannah River Site (SRS) operations has been assessed. The quantity released, the disposition of the radionuclides in the environment, and the dose to offsite individuals has been presented for activation products, carbon cesium, iodine, plutonium, selected fission products, strontium, technetium, tritium, uranium, and the noble gases. An assessment of the impact of nonradioactive mercury also has been published.This document assesses the impact of radioactive transuranics released from SRS facilities since the first reactor became operational late in 1953. The isotopes reported here are 239Np, 241Am, and 244Cm

  1. Avoided intersections of nodal lines

    International Nuclear Information System (INIS)

    Monastra, Alejandro G; Smilansky, Uzy; Gnutzmann, Sven

    2003-01-01

    We consider real eigenfunctions of the Schroedinger operator in 2D. The nodal lines of separable systems form a regular grid, and the number of nodal crossings equals the number of nodal domains. In contrast, for wavefunctions of non-integrable systems nodal intersections are rare, and for random waves, the expected number of intersections in any finite area vanishes. However, nodal lines display characteristic avoided crossings which we study in this work. We define a measure for the avoidance range and compute its distribution for the random wave ensemble. We show that the avoidance range distribution of wavefunctions of chaotic systems follows the expected random wave distributions, whereas for wavefunctions of classically integrable but quantum non-separable systems, the distribution is quite different. Thus, the study of the avoidance distribution provides more support to the conjecture that nodal structures of chaotic systems are reproduced by the predictions of the random wave ensemble

  2. Direct complexonometric determination of thorium (IV), uranium (IV), neptunium (IV), plutonium (IV) by titration of diethylenetriaminepentaacetic acid with xylenol orange as indicator

    International Nuclear Information System (INIS)

    Rykov, A.G.; Piskunov, E.M.; Timofeev, G.A.

    1975-01-01

    The purpose of the present work was to develop a method of determining Th(IV), U(IV), Np(N) and Pu(IV) in acid solutions by titration with diethylenetriamine pentacetic acid, the indicator being xylenol orange. It has been established that Th, U, Np and Pu can be determined to within 0.5-1.5%. Th and U in quantities of tens of milligrams can be determined with greater accuracy, attaining hundredths of one per cent. During titration the determination is not hindered by singly- and doubly-charged metal ions, trivalent lanthanides and actinides, except plutonium. The proposed method can be used to determine U(IV) in the presence of considerable quantities of U(VI) and Np(IV) in the presence of Np(V). Total concentrations of uranium or neptunium are determined by reducing uranium (VI) or neptunium (V) by a standard method (for example, using metallic lead, cadmium or zinc amalgam) to the tetravalent state and applying the method described in the paper. (E.P.)

  3. Who participates in tax avoidance?

    OpenAIRE

    Alstadsæter, Annette; Jacob, Martin

    2013-01-01

    This paper analyzes the sources of heterogeneity in legal tax avoidance strategies across individuals. Three conditions are required for a taxpayer to participate in tax avoidance: incentive, access, and awareness. Using rich Swedish administrative panel data with a unique link between corporate and individual tax returns, we analyze individual participation in legal tax planning around the 2006 Swedish tax reform. Our results suggest that closely held corporations are utilized to facilitate ...

  4. Predator avoidance in extremophile fish.

    Science.gov (United States)

    Bierbach, David; Schulte, Matthias; Herrmann, Nina; Zimmer, Claudia; Arias-Rodriguez, Lenin; Indy, Jeane Rimber; Riesch, Rüdiger; Plath, Martin

    2013-02-06

    Extreme habitats are often characterized by reduced predation pressures, thus representing refuges for the inhabiting species. The present study was designed to investigate predator avoidance of extremophile populations of Poecilia mexicana and P. sulphuraria that either live in hydrogen sulfide-rich (sulfidic) springs or cave habitats, both of which are known to have impoverished piscine predator regimes. Focal fishes that inhabited sulfidic springs showed slightly weaker avoidance reactions when presented with several naturally occurring predatory cichlids, but strongest differences to populations from non-sulfidic habitats were found in a decreased shoaling tendency with non-predatory swordtail (Xiphophorus hellerii) females. When comparing avoidance reactions between P. mexicana from a sulfidic cave (Cueva del Azufre) and the adjacent sulfidic surface creek (El Azufre), we found only slight differences in predator avoidance, but surface fish reacted much more strongly to the non-predatory cichlid Vieja bifasciata. Our third experiment was designed to disentangle learned from innate effects of predator recognition. We compared laboratory-reared (i.e., predator-naïve) and wild-caught (i.e., predator-experienced) individuals of P. mexicana from a non-sulfidic river and found no differences in their reaction towards the presented predators. Overall, our results indicate (1) that predator avoidance is still functional in extremophile Poecilia spp. and (2) that predator recognition and avoidance reactions have a strong genetic basis.

  5. Predator Avoidance in Extremophile Fish

    Science.gov (United States)

    Bierbach, David; Schulte, Matthias; Herrmann, Nina; Zimmer, Claudia; Arias-Rodriguez, Lenin; Indy, Jeane Rimber; Riesch, Rüdiger; Plath, Martin

    2013-01-01

    Extreme habitats are often characterized by reduced predation pressures, thus representing refuges for the inhabiting species. The present study was designed to investigate predator avoidance of extremophile populations of Poecilia mexicana and P. sulphuraria that either live in hydrogen sulfide-rich (sulfidic) springs or cave habitats, both of which are known to have impoverished piscine predator regimes. Focal fishes that inhabited sulfidic springs showed slightly weaker avoidance reactions when presented with several naturally occurring predatory cichlids, but strongest differences to populations from non-sulfidic habitats were found in a decreased shoaling tendency with non-predatory swordtail (Xiphophorus hellerii) females. When comparing avoidance reactions between P. mexicana from a sulfidic cave (Cueva del Azufre) and the adjacent sulfidic surface creek (El Azufre), we found only slight differences in predator avoidance, but surface fish reacted much more strongly to the non-predatory cichlid Vieja bifasciata. Our third experiment was designed to disentangle learned from innate effects of predator recognition. We compared laboratory-reared (i.e., predator-naïve) and wild-caught (i.e., predator-experienced) individuals of P. mexicana from a non-sulfidic river and found no differences in their reaction towards the presented predators. Overall, our results indicate (1) that predator avoidance is still functional in extremophile Poecilia spp. and (2) that predator recognition and avoidance reactions have a strong genetic basis. PMID:25371337

  6. Reduction of neptunium(V) and uranium(VI) in bicarbonate solutions by iron(II)

    International Nuclear Information System (INIS)

    Gogolev, A.V.; Zakharova, E.V.; Rodygina, N.I.; Fedoseev, A.M.; Shilov, V.P.

    2006-01-01

    Interaction of Np(VI) and Fe(II) compounds in bicarbonate solutions is investigated. Interaction of Np(V) with Fe(II) in the presence of phthalate-ions is studied briefly. Fe(II) compounds reduce Np(V) compounds in saturated with Ar or CO 2 solutions with any bicarbonate-ion concentrations. Chemical reaction kinetics is studied. Reduction of U(VI) by Fe(II) compounds takes place in the case of diluted bicarbonate solutions. UO 2 and FeOOH are products of reaction at raised temperatures [ru

  7. Uncertainty avoidance and the exploration-exploitation trade-off

    NARCIS (Netherlands)

    Broekhuizen, Thijs; Giarratana, Marco S.; Torres, Anna

    2017-01-01

    Purpose - This study aims to investigate how a firm's uncertainty avoidance - as indicated by the headquarters' national culture - impacts firm performance by affecting exploratory (product innovation) and exploitative (brand trademark protection) activities. It aims to show that firms characterized

  8. Approach/avoidance in dreams.

    Science.gov (United States)

    Malcolm-Smith, Susan; Koopowitz, Sheri; Pantelis, Eleni; Solms, Mark

    2012-03-01

    The influential threat simulation theory (TST) asserts that dreaming yields adaptive advantage by providing a virtual environment in which threat-avoidance may be safely rehearsed. We have previously found the incidence of biologically threatening dreams to be around 20%, with successful threat avoidance occurring in approximately one-fifth of such dreams. TST asserts that threat avoidance is over-represented relative to other possible dream contents. To begin assessing this issue, we contrasted the incidence of 'avoidance' dreams with that of their opposite: 'approach' dreams. Because TST states that the threat-avoidance function is only fully activated in ecologically valid (biologically threatening) contexts, we also performed this contrast for populations living in both high- and low-threat environments. We find that 'approach' dreams are significantly more prevalent across both contexts. We suggest these results are more consistent with the view that dreaming is generated by reward-seeking systems than by fear-conditioning systems, although reward-seeking is clearly not the only factor determining the content of dreams. Copyright © 2011 Elsevier Inc. All rights reserved.

  9. Standard Test Method for Measuring Reaction Rates by Radioactivation of Neptunium-237

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This test method covers procedures for measuring reaction rates by assaying a fission product (F.P.) from the fission reaction 237Np(n,f)F.P. 1.2 The reaction is useful for measuring neutrons with energies from approximately 0.7 to 6 MeV and for irradiation times up to 30 to 40 years. 1.3 Equivalent fission neutron fluence rates as defined in Practice E 261 can be determined. 1.4 Detailed procedures for other fast-neutron detectors are referenced in Practice E 261. 1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  10. Contribution to the prediction of americium, plutonium and neptunium behaviour in the geosphere: chemical data

    International Nuclear Information System (INIS)

    Robouch, P.

    1989-01-01

    An exhaustive bibliographic review on hydrolysis of americium gives the stability constants, at zero ionic strength. No evidence of Am(OH) 4 - formation was found by solubility studies up to pH 2 (CO 3 ) 3 characterised by its X-ray diffraction pattern is studied at a high ionic strength. All the published results on Am in carbonate media are reinterpreted using these stability constants (Am-OH-CO 3 complexes are not needed). No evidence of Am(CO 3 ) 4 5- formation was found by spectrophotometry up to 3M. Literature results are used to determine the formal redox potentials at pH = 9.4 and to calculate the formation constants, at zero ionic strength. The formation of complexes between americium and humic materials (purified fulvic and humic acids) has been studied by a spectrophotometric technique. The results are interpreted by the formation of a 1:1 complexe. Solubility of the solid PuO 2 (CO 3 ) is measured in bicarbonate media at high ionic strength, to obtain the solubility product and formation constants of the PuO 2 (CO 3 ) i 2-2i complexes [fr

  11. Determination of plutonium and neptunium in various materials by coulometric titration with amperometric indicating

    International Nuclear Information System (INIS)

    Moiseev, I.V.; Kuperman, A.Ya.; Borodina, N.N.; Galkina, V.N.; Nikitskaya, V.N.

    1976-01-01

    Coulometric methods of determining Pu and Np in the products of complex composition containing, in addition to Pu and Np, Cr and Nn have been developed. The methods are based on titration of Pusup((6)) and Npsup((6)) to tetravalent state in H 2 SO 4 -H 3 PO 4 with iron (2) ions generated continuously. A new variant of amperometric method has been proposed for determining end-point of titration. The methods of preparing Pusup((6)) and Npsup((6)) solutions have been developed. It has been shown that, upon dissolution of PuO 2 and NpO 2 by boiling with a mixture of nitric and perchloric acids Pusup((4)) and Npsup((4)) are oxidized quantitatively to Pusup((6)) and Npsup((6)) while Cl 2 , Crsup((6)) and Mnsup((7,4,3)) in the solution obtained are selectively reduced by CHOOH and CH 2 (COOH) 2 . In 6-8 M in terms of H 2 SO 4 solution, ammonium bichromate oxidizes Npsup((4)) to Npsup((6)), Pusup((3)) to Pusup((4)), and Mnsup((2)) to Mnsup((3)). Oxidized Mn and excess of Crsup((6)) are selectively reduced by CHOOH and H 2 C 2 O 4 in 4M in terms of H 2 SO 4 solution

  12. Influence of the redox state on the neptunium sorption under alkaline conditions. Batch sorption studies on titanium dioxide and calcium silicate hydrates

    International Nuclear Information System (INIS)

    Tits, Jan; Laube, Andreas; Wieland, Erich; Gaona, Xavier

    2014-01-01

    Wet chemistry experiments were carried out to investigate the effect of the redox state and aqueous speciation on the uptake of neptunium by titanium dioxide (TiO 2 ) and by calcium silicate hydrates (C-S-H) under alkaline conditions. TiO 2 was chosen as a reference sorbent to determine the surface complexation behaviour of neptunium under alkaline conditions. C-S-H phases are important constituents of cement and concrete. They may contribute significantly to radionuclide retention due to their high recrystallization rates making incorporation the dominating sorption mechanism for many radionuclides (e.g. the actinides) on these materials. The sorption of neptunium on both solids was found to depend strongly on the degree of hydrolysis. On TiO 2 R d values for Np(IV), Np(V) and Np(VI) are identical at pH = 10 and decrease with progressing hydrolysis in case of Np(V) and Np(VI). On C-S-H phases, R d values for the three redox states are also identical at pH = 10. While the R d values for Np(VI) sorption on C-S-H phases decrease with progressing hydrolysis, the R d values for Np(IV) and Np(V) sorption are not affected by the pH. In addition to the effect of hydrolysis, the presence of Ca is found to promote Np(V) and Np(VI) sorption on TiO 2 whereas on C-S-H phases, the present wet chemistry data do not give unambiguous evidence. Thus, the aqueous speciation appears to have a similar influence on the sorption of the actinides on both types of solids despite the different sorption mechanism. The similar R d values for Np(IV,V,VI) sorption at pH = 10 can be explained qualitatively by invoking inter-ligand electrostatic repulsion between OH groups in the coordination sphere of Np(V) and Np(VI). This mechanism was proposed earlier in the literature for the prediction of actinide complexation constants with inorganic ligands. A limiting coordination number for each Np redox state, resulting from the inter-ligand electrostatic repulsion, allows the weaker sorption of the

  13. How to avoid sedation complications

    African Journals Online (AJOL)

    To ensure patient safety, it is crucial that the airway is safeguarded. The single most important responsibility is to protect it. An unobstructed airway, with intact protective reflexes and respiratory drive, is essential to avoid complications. In some procedures, e.g. dental, the airway may need to be shared with the surgeon.

  14. Avoiding plagiarism in academic writing.

    Science.gov (United States)

    Anderson, Irene

    Plagiarism means taking the work of another and presenting it as one's own, resulting in potential upset for the original author and disrepute for the professions involved. This article aims to explore the issue of plagiarism and some mechanisms for detection and avoidance.

  15. Methods to Collect, Compile, and Analyze Observed Short-lived Fission Product Gamma Data

    Energy Technology Data Exchange (ETDEWEB)

    Finn, Erin C.; Metz, Lori A.; Payne, Rosara F.; Friese, Judah I.; Greenwood, Lawrence R.; Kephart, Jeremy D.; Pierson, Bruce D.; Ellis, Tere A.

    2011-09-29

    A unique set of fission product gamma spectra was collected at short times (4 minutes to 1 week) on various fissionable materials. Gamma spectra were collected from the neutron-induced fission of uranium, neptunium, and plutonium isotopes at thermal, epithermal, fission spectrum, and 14-MeV neutron energies. This report describes the experimental methods used to produce and collect the gamma data, defines the experimental parameters for each method, and demonstrates the consistency of the measurements.

  16. Acute carbon dioxide avoidance in Caenorhabditis elegans.

    Science.gov (United States)

    Hallem, Elissa A; Sternberg, Paul W

    2008-06-10

    Carbon dioxide is produced as a by-product of cellular respiration by all aerobic organisms and thus serves for many animals as an important indicator of food, mates, and predators. However, whether free-living terrestrial nematodes such as Caenorhabditis elegans respond to CO2 was unclear. We have demonstrated that adult C. elegans display an acute avoidance response upon exposure to CO2 that is characterized by the cessation of forward movement and the rapid initiation of backward movement. This response is mediated by a cGMP signaling pathway that includes the cGMP-gated heteromeric channel TAX-2/TAX-4. CO2 avoidance is modulated by multiple signaling molecules, including the neuropeptide Y receptor NPR-1 and the calcineurin subunits TAX-6 and CNB-1. Nutritional status also modulates CO2 responsiveness via the insulin and TGFbeta signaling pathways. CO2 response is mediated by a neural circuit that includes the BAG neurons, a pair of sensory neurons of previously unknown function. TAX-2/TAX-4 function in the BAG neurons to mediate acute CO2 avoidance. Our results demonstrate that C. elegans senses and responds to CO2 using multiple signaling pathways and a neural network that includes the BAG neurons and that this response is modulated by the physiological state of the worm.

  17. Study on coordination characteristics of neptunium and uranium ions in calcium nitrate hydrate melt by Raman spectrometry and UV/Vis/NIR spectrometry

    International Nuclear Information System (INIS)

    Fujii, T; Okude, G; Uehara, A; Yamana, H

    2010-01-01

    Extraction behavior of neptunium (Np) by tri-n-butyl phosphate from calcium nitrate hydrate melt was investigated. Distribution ratio of Np was found to increase with the decrease of water content. Adding nitric acid into the system resulted in an increase of the distribution ratio. In order to understand the extraction trends, Np species in the hydrate melt were analyzed by Raman spectrometry and UV/Vis/NIR spectrometry. Major fraction was assigned to be NpO 2 2+ of Np(VI) and small fraction to be NpO 2 + of Np(V). A shift of the v 1 symmetric vibrational frequency of NpO 2 2+ in nitrate media was found in Raman spectra. This suggests a coordination circumstance change of NpO 2 2+ .

  18. JAEA thermodynamic database for performance assessment of geological disposal of high-level and TRU wastes. Refinement of thermodynamic data for tetravalent thorium, uranium, neptunium and plutonium

    International Nuclear Information System (INIS)

    Fujiwara, Kenso; Kitamura, Akira; Yui, Mikazu

    2010-03-01

    Within the scope of the JAEA thermodynamic database project for performance assessment of geological disposal of high-level and TRU radioactive wastes, the refinement of the thermodynamic data for the inorganic compounds and complexes of Thorium(IV), Uranium(IV), Neptunium(IV) and Plutonium(IV) was carried out. Refinement of thermodynamic data for the element was performed on a basis of the thermodynamic database for actinide published by the Nuclear Energy Agency in the Organisation for Economic Co-operation and Development (OECD/NEA). Additionally, the latest data after publication of thermodynamic data by OECD/NEA were reevaluated to determine whether the data should be included in the JAEA-TDB. (author)

  19. Contribution to the study of liquid-liquid extraction dynamics in the case of fast transfers. Extractions of uranium, plutonium and neptunium in a laboratory centrifugal extractor

    International Nuclear Information System (INIS)

    Bergeonneau, Philippe

    1978-01-01

    The liquid-liquid extraction (also named solvent-based extraction) is a very important technique for the reprocessing of irradiated nuclear fuels. This research thesis is based on the use of a laboratory centrifugal extractor which allows interesting conditions to be achieved: fast transfer due to an intense solution mixing, very short duration of contact between solutions. Thus, after a report of a bibliographical study on chemical mechanisms of extraction, on the composition of extracted species, on extraction kinetics, and on centrifugal extractors, this thesis reports the design, fabrication and use of a centrifugal extractor: presentation of fundamental principles, description and characteristics (materials, hydrodynamic operation test and problems, prototype). It reports studies of fast transfer kinetics: mathematical processing, result interpretation, results and discussions of extraction kinetics for nitric acid, uranium VI and IV, plutonium IV, neptunium IV, and comparison of the different extraction kinetics

  20. Avoiding Complications with MPFL Reconstruction.

    Science.gov (United States)

    Smith, Marvin K; Werner, Brian C; Diduch, David R

    2018-05-12

    To discuss the potentially significant complications associated with medial patellofemoral ligament (MPFL) reconstruction. Additionally, to review the most current and relevant literature with an emphasis on avoiding these potential complications. Multiple cadaveric studies have characterized the anatomy of the MPFL and the related morphologic abnormalities that contribute to recurrent lateral patellar instability. Such abnormalities include patella alta, excessive tibial tubercle to trochlear grove (TT-TG) distance, trochlear dysplasia, and malalignment. Recent studies have evaluated the clinical outcomes associated with the treatment of concomitant pathology in combination with MPFL reconstruction, which is critical in avoiding recurrent instability and complications. Although there remains a lack of consensus regarding various critical aspects of MPFL reconstruction, certain concepts remain imperative. Our preferred methods and rationales for surgical techniques are described. These include appropriate work up, a combination of procedures to address abnormal morphology, anatomical femoral insertion, safe and secure patellar fixation, appropriate graft length fixation, and thoughtful knee flexion during fixation.

  1. Avoidant personality disorder: current insights

    OpenAIRE

    Lampe,Lisa; Malhi,Gin

    2018-01-01

    Lisa Lampe,1 Gin S Malhi2 1Discipline of Psychiatry, University of Newcastle, Newcastle, NSW, Australia; 2Discipline of Psychiatry, University of Sydney, Sydney, NSW, Australia Abstract: Avoidant personality disorder (AVPD) is a relatively common disorder that is associated with significant distress, impairment, and disability. It is a chronic disorder with an early age at onset and a lifelong impact. Yet it is underrecognized and poorly studied. Little is known regarding the most effective t...

  2. Pathogen avoidance by insect predators

    OpenAIRE

    Meyling, Nicolai V.; Ormond, Emma; Roy, Helen E.; Pell, Judith K.

    2008-01-01

    Insects can detect cues related to the risk of attack by their natural enemies. Pathogens are among the natural enemies of insects and entomopathogenic fungi attack a wide array of host species. Evidence documents that social insects in particular have adapted behavioural mechanisms to avoid infection by fungal pathogens. These mechanisms are referred to as 'behavioural resistance'. However, there is little evidence for similar adaptations in non-social insects. We have conducted experime...

  3. Avoidant personality disorder: current insights

    Directory of Open Access Journals (Sweden)

    Lampe L

    2018-03-01

    Full Text Available Lisa Lampe,1 Gin S Malhi2 1Discipline of Psychiatry, University of Newcastle, Newcastle, NSW, Australia; 2Discipline of Psychiatry, University of Sydney, Sydney, NSW, Australia Abstract: Avoidant personality disorder (AVPD is a relatively common disorder that is associated with significant distress, impairment, and disability. It is a chronic disorder with an early age at onset and a lifelong impact. Yet it is underrecognized and poorly studied. Little is known regarding the most effective treatment. The impetus for research into this condition has waxed and waned, possibly due to concerns regarding its distinctiveness from other disorders, especially social anxiety disorder (SAD, schizoid personality disorder, and dependent personality disorder. The prevailing paradigm subscribes to the “severity continuum hypothesis”, in which AVPD is viewed essentially as a severe variant of SAD. However, areas of discontinuity have been described, and there is support for retaining AVPD as a distinct diagnostic category. Recent research has focused on the phenomenology of AVPD, factors of possible etiological significance such as early parenting experiences, attachment style, temperament, and cognitive processing. Self-concept, avoidant behavior, early attachments, and attachment style may represent points of difference from SAD that also have relevance to treatment. Additional areas of research not focused specifically on AVPD, including the literature on social cognition as it relates to attachment and personality style, report findings that are promising for future research aimed at better delineating AVPD and informing treatment. Keywords: avoidant personality disorder, social anxiety disorder, social cognition, psychotherapy, attachment

  4. Avoiding congestion in recommender systems

    International Nuclear Information System (INIS)

    Ren, Xiaolong; Lü, Linyuan; Liu, Runran; Zhang, Jianlin

    2014-01-01

    Recommender systems use the historical activities and personal profiles of users to uncover their preferences and recommend objects. Most of the previous methods are based on objects’ (and/or users’) similarity rather than on their difference. Such approaches are subject to a high risk of increasingly exposing users to a narrowing band of popular objects. As a result, a few objects may be recommended to an enormous number of users, resulting in the problem of recommendation congestion, which is to be avoided, especially when the recommended objects are limited resources. In order to quantitatively measure a recommendation algorithm's ability to avoid congestion, we proposed a new metric inspired by the Gini index, which is used to measure the inequality of the individual wealth distribution in an economy. Besides this, a new recommendation method called directed weighted conduction (DWC) was developed by considering the heat conduction process on a user–object bipartite network with different thermal conductivities. Experimental results obtained for three benchmark data sets showed that the DWC algorithm can effectively avoid system congestion, and greatly improve the novelty and diversity, while retaining relatively high accuracy, in comparison with the state-of-the-art methods. (paper)

  5. Distribution behavior of uranium, neptunium, rare-earth elements (Y, La, Ce, Nd, Sm, Eu, Gd) and alkaline-earth metals (Sr,Ba) between molten LiCl-KCl eutectic salt and liquid cadmium or bismuth

    International Nuclear Information System (INIS)

    Kurata, M.; Sakamura, Y.; Hijikata, T.; Kinoshita, K.

    1995-01-01

    Distribution coefficients of uranium neptunium, eight rare-earth elements (Y, La, Ce, Pr, Nd, Sm, Eu and Gd) and two alkaline-earth metals (Sr and Ba) between molten LiCl-KCl eutectic salt and either liquid cadmium or bismuth were measured at 773 K. Separation factors of trivalent rare-earth elements to uranium or neptunium in the LiCl-KCl/Bi system were by one or two orders of magnitude larger than those in the LiCl-KCl/Cd system. On the contrary, the separation factors of alkaline-earth metals and divalent rare-earth elements to trivalent rare-earth elements were by one or two orders of magnitude smaller in the LiCl-KCl/Bi system. (orig.)

  6. AVOID BECOMING A VICTIM OF COUNTERFEIT ITEMS

    Energy Technology Data Exchange (ETDEWEB)

    WARRINER RD

    2011-07-13

    In today's globalized economy, we cannot live without imported products. Most people do not realize how thin the safety net of regulation and inspection really is. Less than three percent of imported products receive any form of government inspection prior to sale. Avoid flea markets, street vendors and deep discount stores. The sellers of counterfeit wares know where to market their products. They look for individuals who are hungry for a brand name item but do not want to pay a brand name price for it. The internet provides anonymity to the sellers of counterfeit products. Unlike Europe, U.S. law does not hold internet-marketing organizations, responsible for the quality of the products sold on their websites. These organizations will remove an individual vendor when a sufficient number of complaints are lodged, but they will not take responsibility for the counterfeit products you may have purchased. EBay has a number of counterfeit product guides to help you avoid being a victim of the sellers of these products. Ten percent of all medications taken worldwide are counterfeit. If you do buy medications on-line, be sure that the National Association of Boards of Pharmacy Verified Internet Pharmacy Practice Sites (VIPPS) recommends the pharmacy you choose to use. Inspect all medication purchases and report any change in color, shape, imprinting or odor to your pharmacist. If you take generic medications these attributes may change from one manufacturer to another. Your pharmacist should inform you of any changes when you refill your prescription. If they do not, get clarification prior to taking the medication. Please note that the Federal Drug Administration (FDA) does not regulate supplements. The FDA only steps in when a specific supplement proves to cause physical harm or contains a regulated ingredient. Due to counterfeiting, Underwriters Laboratories (UL) changed their label design three times since 1996. The new gold label should be attached to the cord

  7. Mechanism of avoiding little rip

    OpenAIRE

    ZHAI Xianghua; XI Ping

    2014-01-01

    The scalar phantom field Φ leads to various catastrophic fates of the universe including big rip,little rip and other future singularity depending on the choice of its potential.For example,little rip stems from a quadratic potential in general relativity.We suggest a new mechanism to avoid little rip in the 1/R gravity.The phantom field with different potentials,including quadratic,cubic and quantic potentials are studied via numerical calculation in the 1/R gravity with R2 correction.T...

  8. The sorption of uranium(VI) and neptunium(V) onto surfaces of selected metal oxides and alumosilicates studied by in situ vibrational spectroscopy

    International Nuclear Information System (INIS)

    Mueller, Katharina

    2010-05-01

    The migration behavior of actinides and other radioactive contaminants in the environment is controlled by prominent molecular phenomena such as hydrolysis and complexation reactions in aqueous solutions as well as the diffusion and sorption onto minerals present along groundwater flow paths. These reactions significantly influence the mobility and bioavailability of the metal ions in the environment, in particular at liquid-solid interfaces. Hence, for the assessment of migration processes the knowledge of the mechanisms occurring at interfaces is crucial. The required structural information can be obtained using various spectroscopic techniques. In the present study, the speciation of uranium(VI) and neptunium(V) at environmentally relevant mineral-water interfaces of oxides of titania, alumina, silica, zinc, and alumosilicates has been investigated by the application of attenuated total reflection Fouriertransform infrared (ATR FT-IR) spectroscopy. Moreover, the distribution of the hydrolysis products in micromolar aqueous solutions of U(VI) and Np(V/VI) at ambient atmosphere has been characterized for the first time, by a combination of ATR FT-IR spectroscopy, near infrared (NIR) absorption spectroscopy, and speciation modeling applying updated thermodynamic databases. From the infrared spectra, a significant change of the U(VI) speciation is derived upon lowering the U(VI) concentration from the milli- to the micromolar range, strongly suggesting the dominance of monomeric U(VI) hydrolysis products in the micromolar solutions. In contradiction to the predicted speciation, monomeric hydroxo species are already present at pH ≥ 2.5 and become dominant at pH 3. At higher pH levels (> 6), a complex speciation is evidenced including carbonate containing complexes. For the first time, spectroscopic results of Np(VI) hydrolysis reactions are provided in the submillimolar concentration range and at pH values up to 5.3, and they are comparatively discussed with U

  9. Avoidant personality disorder: current insights.

    Science.gov (United States)

    Lampe, Lisa; Malhi, Gin S

    2018-01-01

    Avoidant personality disorder (AVPD) is a relatively common disorder that is associated with significant distress, impairment, and disability. It is a chronic disorder with an early age at onset and a lifelong impact. Yet it is underrecognized and poorly studied. Little is known regarding the most effective treatment. The impetus for research into this condition has waxed and waned, possibly due to concerns regarding its distinctiveness from other disorders, especially social anxiety disorder (SAD), schizoid personality disorder, and dependent personality disorder. The prevailing paradigm subscribes to the "severity continuum hypothesis", in which AVPD is viewed essentially as a severe variant of SAD. However, areas of discontinuity have been described, and there is support for retaining AVPD as a distinct diagnostic category. Recent research has focused on the phenomenology of AVPD, factors of possible etiological significance such as early parenting experiences, attachment style, temperament, and cognitive processing. Self-concept, avoidant behavior, early attachments, and attachment style may represent points of difference from SAD that also have relevance to treatment. Additional areas of research not focused specifically on AVPD, including the literature on social cognition as it relates to attachment and personality style, report findings that are promising for future research aimed at better delineating AVPD and informing treatment.

  10. Avoidant personality disorder: current insights

    Science.gov (United States)

    Lampe, Lisa; Malhi, Gin S

    2018-01-01

    Avoidant personality disorder (AVPD) is a relatively common disorder that is associated with significant distress, impairment, and disability. It is a chronic disorder with an early age at onset and a lifelong impact. Yet it is underrecognized and poorly studied. Little is known regarding the most effective treatment. The impetus for research into this condition has waxed and waned, possibly due to concerns regarding its distinctiveness from other disorders, especially social anxiety disorder (SAD), schizoid personality disorder, and dependent personality disorder. The prevailing paradigm subscribes to the “severity continuum hypothesis”, in which AVPD is viewed essentially as a severe variant of SAD. However, areas of discontinuity have been described, and there is support for retaining AVPD as a distinct diagnostic category. Recent research has focused on the phenomenology of AVPD, factors of possible etiological significance such as early parenting experiences, attachment style, temperament, and cognitive processing. Self-concept, avoidant behavior, early attachments, and attachment style may represent points of difference from SAD that also have relevance to treatment. Additional areas of research not focused specifically on AVPD, including the literature on social cognition as it relates to attachment and personality style, report findings that are promising for future research aimed at better delineating AVPD and informing treatment. PMID:29563846

  11. Avoidable cost of alcohol abuse in Canada.

    Science.gov (United States)

    Rehm, Jürgen; Patra, Jayadeep; Gnam, William H; Sarnocinska-Hart, Anna; Popova, Svetlana

    2011-01-01

    To estimate avoidable burden and avoidable costs of alcohol abuse in Canada for the year 2002. A policy effectiveness approach was used. The impact of six effective and cost-effective alcohol policy interventions aimed to reduce alcohol consumption was modeled. In addition, the effect of privatized alcohol sales that would increase alcohol consumption and alcohol-attributable costs was also modeled. The effects of these interventions were compared with the baseline (aggregate) costs obtained from the second Canadian Study of Social Costs Attributable to Substance Abuse. It was estimated that by implementing six cost-effective policies from about 900 million to two billion Canadian dollars per year could be saved in Canada. The greatest savings due to the implementation of these interventions would be achieved in the lowering of productivity losses, followed by health care, and criminality. Substantial increases in burden and cost would occur if Canadian provinces were to privatize alcohol sales. The implementation of proven effective population-based interventions would reduce alcohol-attributable burden and its costs in Canada to a considerable degree. Copyright © 2010 S. Karger AG, Basel.

  12. Collision avoidance in robotic environments

    International Nuclear Information System (INIS)

    Kreifeldt, J.G.

    1984-01-01

    A generalized approach to the problem of collision avoidance in robotic environments is presented. This approach transforms the three dimensional but dynamic real-world changing geometric space of the robot in its environment into a multidimensional but static space such that any possible geometric arrangement of the robotic space becomes a point in hyperspace. Major advantages of this approach include clarification of and potential solution to the basic problem of finding optimized, collision free movements from an initial to a final configuration. A major disadvantage of the approach is related to computational and data storage problems. However these latter are technically solvable while the clarification of the control and guidance problem gained through the transformational approach and its general elucidation power remain prime conceptual tools for the problem of robot design and operation

  13. Avoidant/Restrictive Food Intake Disorder

    Science.gov (United States)

    ... Eating Disorder Bulimia Nervosa Pica Rumination Disorder Avoidant/restrictive food intake disorder is characterized by eating very little food and/or avoiding eating certain foods. People with this disorder eat ...

  14. The Global Attack on Tax Avoidance

    OpenAIRE

    Franck, Gustav Grønborg; Runchel, Daniel Theis; Mac, Martin Tuannhien; Ahmed, Jahanzeeb; Bang, Lars Seneca

    2015-01-01

    The issue of tax avoidance has been subject for recommended regulations by the G20 countries in collaboration with OECD. We examine the usefulness of market failure theory to explain the economic and political issues of tax avoidance. We test our hypothesis using theory through a deductive approach incorporating content analysis to find convergence(s) between tax avoidance methods identified and the efforts of the G20 BEPS action plan to respond to those methods. The issue of tax avoidance...

  15. Determination of neutron resonance parameters of Neptunium 237 between 0 and 500 eV. The covariance matrices of statistical and of systematic origin, relating the resonance parameters, are also given; Determination des parametres des resonances neutroniques du neptunium 237, en dessous de 500eV, et obtention des matrices de covariances statistiques et systematiques entre les parametres de ces resonances

    Energy Technology Data Exchange (ETDEWEB)

    Lepretre, A.; Herault, N. [CEA Saclay, Dept. d' Astrophysique de Physique des Particules, de Physique Nucleaire et de l' Instrumentation Associee, 91- Gif sur Yvette (France); Brusegan, A.; Noguere, G.; Siegler, P. [Institut des Materiaux et des Metrologies - IRMM, Joint Research Centre, Gell (Belgium)

    2002-12-01

    This report is a follow up of the report CEA DAPNIA/SPHN-99-04T of Vincent Gressier. In the frame of a collaboration between the 'Commissariat a l'Energie Atomique (CEA)' and the Institute for Reference Materials and Measurement (IRMM, Geel, Belgique), the resonance parameters of neptunium 237 have been determined in the energy interval between 0 and 500 eV. These parameters have been obtained by using the Refit code in analysing simultaneously three transmission experiments. The covariance matrix of statistical origin is provided. A new method, based on various sensitivity studies is proposed for determining also the covariance matrix of systematic origin, relating the resonance parameters. From an experimental viewpoint, the study indicated that, with a large probability, the background spectrum has structure. A two dimensional profiler for the neutron density has been proved feasible. Such a profiler could, among others, demonstrate the existence of the structured background. (authors)

  16. Conflict Avoidance in a University Context

    Science.gov (United States)

    Barsky, Allan E.; Wood, Lorinda

    2005-01-01

    This ethnographic study explores patterns of conflict avoidance among university students, professors, administrators and staff. Analysis of their narratives of conflict avoidance suggests that avoidance can be beneficial in some circumstances, depending upon personality issues, cost?benefit analysis, power imbalance, type of work, length of…

  17. Population avoidance in aimpoint selection

    International Nuclear Information System (INIS)

    Andre, C.G.

    1978-01-01

    In most past studies of the effectiveness of tactical nuclear weapons vs the amount of collateral damage produced (civilian casualties), civilians have been congregated into idealized shaped towns and cities, and criteria for city avoidance were usually formulated in terms relating to a town's population. This treatment was sufficient in those studies where weapon yields were so large that great numbers of civilians were almost always placed at risk. As further studies developed, demonstrating that real progress could be made in reducing the numbers of civilians potentially placed at risk in tactical nuclear warfare situations, the inadequacies of the present treatment became obvious. The need existed for a more detailed description of the distribution of civilians. The method described determines the number of civilians at risk for a weapon under consideration being detonated at a given point and displays a symbol relating to the numbers at risk on a map or a transparency that overlays a 1:50,000 map of the region. Thus, a weapons planner making the selection of aimpoints for inflicting the necessary military damage required has the means to reduce potential civilian casualties by properly choosing the weapon and aimpoints

  18. Earthworm avoidance of silver nanomaterials over time

    DEFF Research Database (Denmark)

    Mariyadas, Jennifer; Amorim, Mónica J B; Jensen, John

    2018-01-01

    Avoidance behaviour offers a highly relevant information as it reveals the ability to avoid (or not) possible toxic compounds in the field, hence it provides information on reasons for the presence/absence in the field. The earthworm Eisenia fetida was used to study avoidance behaviour to four si...... exposure durations and showed a continuous higher avoidance with time (based on EC50 values). The AgNMs avoidance was in the order NM300Ksoil solution fraction that correlated with EC50 across materials....

  19. Avoidable sickness absence in a dutch working population

    NARCIS (Netherlands)

    Kremer, A.M.; Steenbeek, R.

    2010-01-01

    Introduction Sickness absence has an important impact on employers (e.g. reduced productivity, high costs) and employees (e.g. replacement, job loss). Therefore, we investigated possible reduction by exploring avoidable sickness absence. Methods A questionnaire was filled out by 2,954 Dutch workers

  20. Generalization of socially transmitted and instructed avoidance

    Directory of Open Access Journals (Sweden)

    Gemma eCameron

    2015-06-01

    Full Text Available Excessive avoidance behavior, in which an instrumental action prevents an upcoming aversive event, is a defining feature of anxiety disorders. Left unchecked, both fear and avoidance of potentially threatening stimuli may generalize to perceptually related stimuli and situations. The behavioral consequences of generalization mean that aversive learning experiences with specific threats may lead people to infer that classes of related stimuli are threatening, potentially dangerous, and need to be avoided, despite differences in physical form. Little is known about avoidance generalization in humans and the learning pathways by which it may be transmitted. In the present study, we compared two pathways to avoidance, instructions and social observation, on subsequent generalization of avoidance behavior, fear expectancy and physiological arousal. Participants first learned that one cue was a danger cue (conditioned stimulus, CS+ and another was a safety cue (CS-. Groups then were either instructed that a simple avoidance response in the presence of the CS+ cancelled upcoming shock presentations (instructed-learning group or observed a short movie showing a demonstrator performing the avoidance response to prevent shock (observational-learning group. During generalization testing, danger and safety cues were presented along with generalization stimuli that parametrically varied in perceptual similarity to the CS+. Reinstatement of fear and avoidance was also tested. Findings demonstrate, for the first time, generalization of socially transmitted and instructed avoidance: both groups showed comparable generalization gradients in fear expectancy, avoidance behavior and arousal. Return of fear was evident, suggesting that generalized avoidance remains persistent following extinction testing. The utility of the present paradigm for research on avoidance generalization is discussed.

  1. Integration of Weather Avoidance and Traffic Separation

    Science.gov (United States)

    Consiglio, Maria C.; Chamberlain, James P.; Wilson, Sara R.

    2011-01-01

    This paper describes a dynamic convective weather avoidance concept that compensates for weather motion uncertainties; the integration of this weather avoidance concept into a prototype 4-D trajectory-based Airborne Separation Assurance System (ASAS) application; and test results from a batch (non-piloted) simulation of the integrated application with high traffic densities and a dynamic convective weather model. The weather model can simulate a number of pseudo-random hazardous weather patterns, such as slow- or fast-moving cells and opening or closing weather gaps, and also allows for modeling of onboard weather radar limitations in range and azimuth. The weather avoidance concept employs nested "core" and "avoid" polygons around convective weather cells, and the simulations assess the effectiveness of various avoid polygon sizes in the presence of different weather patterns, using traffic scenarios representing approximately two times the current traffic density in en-route airspace. Results from the simulation experiment show that the weather avoidance concept is effective over a wide range of weather patterns and cell speeds. Avoid polygons that are only 2-3 miles larger than their core polygons are sufficient to account for weather uncertainties in almost all cases, and traffic separation performance does not appear to degrade with the addition of weather polygon avoidance. Additional "lessons learned" from the batch simulation study are discussed in the paper, along with insights for improving the weather avoidance concept. Introduction

  2. Avoidance of Ag nanoparticles by earthworms, Eisenia fetida

    DEFF Research Database (Denmark)

    Mariyadas, Jennifer; Mónica, Amorim; Scott-Fordsmand, Janeck James

    2013-01-01

    Earthworms are key sentinel organisms playing an important role in improving the soil structure. Here we tested the avoidance behaviour of earthworms, Eisenia fetida to silver nanoparticles (Ag NPs). Silver nanoparticles are widely used in a range of consumer products mainly as antibacterial agents....... The avoidance behaviour could not be explained by the release of silver ions in the soil-solution. Although, Ag-ions release (if any) may still have had an influence on behaviour. The present results suggests that the earthworms perceive the presence of actual nanoparticles in the soil. Our results suggest that...... and thus causes potential risk to the environment once these particles are released into the environment [1]. In our tests, we were able to show that the earthworms avoided commercially fabricated silver nanoparticles in a dose and time dependent manner. The earthworms were exposed to 3 nanoparticles: NM...

  3. Solar Avoided Cost Solution SunShot 6 Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Tucker, John [Genability, San Francisco, CA (United States); Danziger, Eric [Genability, San Francisco, CA (United States)

    2014-01-29

    The core objectives of this project were two separate but integrated products, collectively providing game-changing Avoided Cost capabilities. The first was a kit of avoided cost tools and data that any solar provider can use a-lacarte or as a whole. It’s open and easily accessible nature allows the rapid and accurate calculation of avoided cost in whatever context and software that make sense (“Typical and Avoided Cost Tools”). This kit includes a dataset of typical energy rates, costs and usage that can be used for solar prospecting, lead generation and any situation where data about an opportunity is missing or imperfect. The second is a web application and related APIs specifically built for solar providers to radically streamline their lead-to-sale process (“Solar Provider Module”). The typical and Avoided Cost tools are built directly into this, and allow for solar providers to track their opportunities, collaborate with their installers and financiers, and close more sales faster.

  4. A Demonstration of Approach and Avoidance Conflicts

    Science.gov (United States)

    Terry, W. Scott

    2010-01-01

    Choosing between 2 unpleasant alternatives (Would you rather be less intelligent or less attractive?) is more difficult than choosing between two desirable options (Would you rather be more intelligent or more attractive?). Here I describe a classroom demonstration of avoidance-avoidance conflicts. Students make a series of approach-approach and…

  5. Effects of IFRS adoption on tax avoidance

    Directory of Open Access Journals (Sweden)

    Renata Nogueira Braga

    Full Text Available ABSTRACT This study investigates the association between mandatory International Financial Reporting Standards (IFRS adoption and corporate tax avoidance. In this study, tax avoidance is defined as a reduction in the effective corporate income tax rate through tax planning activities, whether these are legal, questionable, or even illegal. Three measures of tax avoidance are used and factors at the country and firm level (that have already been associated with tax avoidance in prior research are controlled. Using samples that range from 9,389 to 15,423 publicly-traded companies from 35 countries, covering 1999 to 2014, it is found that IFRS adoption is associated with higher levels of corporate tax avoidance, even when the level of book-tax conformity required in the countries and the volume of accruals are controlled, both of which are considered potential determinants of this relationship. Furthermore, the results suggest that after IFRS adoption, firms in higher book-tax conformity environments engage more in tax avoidance than firms in lower book-tax conformity environments. It is also identified that engagement in tax avoidance after IFRS adoption derives not only from accruals management, but also from practices that do not involve accruals. The main conclusion is that companies engage more in tax avoidance after mandatory IFRS adoption.

  6. Investigation of the system ThO2-NpO2-P2O5. Solid solutions of thorium-neptunium (IV) phosphate-diphosphate

    International Nuclear Information System (INIS)

    Dacheux, N.; Thomas, A.C.; Brandel, V.; Genet, M.

    1998-01-01

    Considering that phosphate matrices could be potential candidates for the immobilization of actinides or for the final disposal of the excess plutonium from dismantled nuclear weapons, the chemistry of thorium phosphates has been re-examined. In the ThO 2 -P 2 O 5 system, the thorium phosphate-diphosphate Th 4 (PO 4 ) 4 P 2 O 7 (TPD) can be synthesized by wet and dry chemical processes. The substitution of thorium by other tetravalent actinides like uranium or plutonium can be obtained for 0 4-x Np x (PO 4 ) 4 P 2 O 7 (TNPD) with 0 4+ by Np 4+ in the TPD structure is evaluated to 2.08 (which corresponds to about 52 mol% of thorium replaced by neptunium (IV)). The field of existence of solid solutions Th 4-x U -x Np -x Pu U x U Np x Np Pu x Pu (PO 4 )4P 2 O 7 has been calculated. These solid solutions should be synthesized for 5x U +7x Np +9x Pu ≤15. In the NpO 2 -P 2 O 5 system, the unit cell parameters of Np 2 O(PO 4 ) 2 were refined by analogy with U 2 O(PO 4 ) 2 which crystallographic data have been published recently. For Np 2 O(PO 4 ) 2 the unit cell is orthorhombic with the following cell parameters: a=7.033(2)A, b=9.024(3)A, c=12.587(6)A and V=799(1)A 3 . The unit cell parameter obtained for α-NpP 2 O 7 (a=8.586(1)A) is in good agreement with those already reported in literature. (orig.)

  7. Higher threat avoidance costs reduce avoidance behaviour which in turn promotes fear extinction in humans.

    Science.gov (United States)

    Rattel, Julina A; Miedl, Stephan F; Blechert, Jens; Wilhelm, Frank H

    2017-09-01

    Theoretical models specifying the underlying mechanisms of the development and maintenance of anxiety and related disorders state that fear responses acquired through classical Pavlovian conditioning are maintained by repeated avoidance behaviour; thus, it is assumed that avoidance prevents fear extinction. The present study investigated behavioural avoidance decisions as a function of avoidance costs in a naturalistic fear conditioning paradigm. Ecologically valid avoidance costs - manipulated between participant groups - were represented via time-delays during a detour in a gamified computer task. After differential acquisitions of shock-expectancy to a predictive conditioned stimulus (CS+), participants underwent extinction where they could either take a risky shortcut, while anticipating shock signaled by the CS+, or choose a costly avoidance option (lengthy detour); thus, they were faced with an approach-avoidance conflict. Groups with higher avoidance costs (longer detours) showed lower proportions of avoiders. Avoiders gave heightened shock-expectancy ratings post-extinction, demonstrating 'protecting from extinction', i.e. failure to extinguish. Moreover, there was an indirect effect of avoidance costs on protection from extinction through avoidance behaviour. No moderating role of trait-anxiety was found. Theoretical implications of avoidance behaviour are discussed, considering the involvement of instrumental learning in the maintenance of fear responses. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Ecology: avoidance of disease by social lobsters.

    Science.gov (United States)

    Behringer, Donald C; Butler, Mark J; Shields, Jeffrey D

    2006-05-25

    Transmissible pathogens are the bane of social animals, so they have evolved behaviours to decrease the probability of infection. There is no record, however, of social animals avoiding diseased individuals of their own species in the wild. Here we show how healthy, normally gregarious Caribbean spiny lobsters (Panulirus argus) avoid conspecifics that are infected with a lethal virus. Early detection and avoidance of infected, though not yet infectious, individuals by healthy lobsters confers a selective advantage and highlights the importance of host behaviour in disease transmission among natural populations.

  9. U3O8; process avoids sulphates and chlorides

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    A brief description is given of a yellowcake precipitation process developed by Intercontinental Energy Crop. for its in-situ uranium leaching opeartions in Texas. The process uses neither sulfates nor chlorides, and thereby avoids formation of uranium salts that require high-temperature calciners. After the precipitation of yellowcake, a rotary vacuum dryer accepts a yellowcake containing 30% solids, and produces a dry product ready for packaging

  10. Toddlers at the Table: Avoiding Power Struggles

    Science.gov (United States)

    ... Search English Español Toddlers at the Table: Avoiding Power Struggles KidsHealth / For Parents / Toddlers at the Table: ... common concerns into opportunities to teach healthy eating habits. Most Toddlers Are Picky Eaters Many toddlers express ...

  11. How to avoid overheating during exercise

    Science.gov (United States)

    ... patientinstructions/000865.htm How to avoid overheating during exercise To use the sharing features on this page, ... condition can get heat illness. Stay Cool During Exercise Try these tips to help prevent heat-related ...

  12. Directional Collision Avoidance in Ad Hoc Networks

    National Research Council Canada - National Science Library

    Wang, Yu; Garcia-Luna-Aceves, J. J

    2004-01-01

    This paper analyzes the performance of directional collision avoidance schemes, in which antenna systems are used to direct the transmission and reception of control and data packets in channel access...

  13. Foods to Avoid or Limit during Pregnancy

    Science.gov (United States)

    ... Global Map Premature Birth Report Cards Careers Archives Pregnancy Before or between pregnancies Nutrition, weight & fitness Prenatal ... during pregnancy Foods to avoid or limit during pregnancy E-mail to a friend Please fill in ...

  14. The challenges for scientists in avoiding plagiarism.

    Science.gov (United States)

    Fisher, E R; Partin, K M

    2014-01-01

    Although it might seem to be a simple task for scientists to avoid plagiarism and thereby an allegation of research misconduct, assessment of trainees in the Responsible Conduct of Research and recent findings from the National Science Foundation Office of Inspector General regarding plagiarism suggests otherwise. Our experiences at a land-grant academic institution in assisting researchers in avoiding plagiarism are described. We provide evidence from a university-wide multi-disciplinary course that understanding how to avoid plagiarism in scientific writing is more difficult than it might appear, and that a failure to learn the rules of appropriate citation may cause dire consequences. We suggest that new strategies to provide training in avoiding plagiarism are required.

  15. Dual Eligibles and Potentially Avoidable Hospitalizations

    Data.gov (United States)

    U.S. Department of Health & Human Services — About 25 percent of the hospitalizations for dual eligible beneficiaries in 2005 were potentially avoidable. Medicare and Medicaid spending for those potentially...

  16. Avoiding Anemia: Boost Your Red Blood Cells

    Science.gov (United States)

    ... Issues Subscribe January 2014 Print this issue Avoiding Anemia Boost Your Red Blood Cells En español Send ... Disease When Blood Cells Bend Wise Choices Preventing Anemia To prevent or treat iron-deficiency anemia: Eat ...

  17. ADVERTISING AVOIDANCE PADA IKLAN DI MEDIA TELEVISI

    OpenAIRE

    Indah Dwi Pratama; Ujang Sumarwan; Hari Wijayanto

    2016-01-01

    One factor that can interfere with the absorption rate of viewers on television advertisement is advertising avoidance which shows the difference between the number of viewers who watch advertisement programs and the number of viewers who watch television programs. The factors that affect advertising avoidance include the demography of the viewers (gender, age, area of residence, and social economic status, or SES), advertising attributes (the television stations, order of ads, genre of the p...

  18. Banking deregulation and corporate tax avoidance

    Directory of Open Access Journals (Sweden)

    Bill B. Francis

    2017-06-01

    Full Text Available We investigate whether tax avoidance substitutes for external financing. We exploit interstate banking deregulation as a quasi-external shock to examine whether firms engage in less tax avoidance after banking deregulation, because of cheaper and easier access to credit from banks. We find no empirical evidence to support this substitutive relation, even for firms with higher financial constraints or firms with higher external financing dependence.

  19. Sinkhole Avoidance Routing in Wireless Sensor Networks

    Science.gov (United States)

    2011-05-09

    COVERED (From- To) 09-05-2011 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Sinkhole Avoidance Routing in Wireless Sensor Networks 5b . GRANT NUMBER . 5c...reliability of wireless sensor networks. 15. SUBJECT TERMS wireless sensor networks, sinkhole attack, routing protocol 16. SECURITY CLASSIFICATION...Include area code) Standard Form 298 (Rev. 8/98) Prescribed by ANSI Std . Z39.18 1 Sinkhole Avoidance Routing in Wireless Sensor Networks MIDN 1/C

  20. Pathological demand avoidance: Exploring the behavioural profile.

    OpenAIRE

    O Nions, E.; Viding, E.; Greven, C. U.; Ronald, A.; Happé, F.

    2014-01-01

    'Pathological Demand Avoidance' is a term increasingly used by practitioners in the United Kingdom. It was coined to describe a profile of obsessive resistance to everyday demands and requests, with a tendency to resort to 'socially manipulative' behaviour, including outrageous or embarrassing acts. Pathological demand avoidance is thought to share aspects of social impairment with autism spectrum disorders, but autism spectrum disorder-appropriate strategies, such as routine and repetition, ...

  1. The mediation effect of experiential avoidance between coping and psychopathology in chronic pain.

    Science.gov (United States)

    Costa, Joana; Pinto-Gouveia, José

    2011-01-01

    This study explores experiential avoidance as a mediator in the relationship between coping (rational coping, avoidant coping and detached/ emotional coping) and psychopathology (depression, anxiety and stress). A battery of self-report questionnaires was used to assess coping, experiential avoidance and depression, anxiety and stress in 70 participants with a chronic pain from Portuguese primary health care units. Regression analyses were performed and showed preliminary evidence supporting the mediation role of experiential avoidance in a Portuguese sample with chronic pain. Results show that experiential avoidance partially or fully mediate the effects of rational coping and detached/emotional coping on depression and stress. Implications for clinical practice were discussed and suggest that psychopathology is not necessary direct product of coping and other processes, such as experiential avoidance, are likely involved. Copyright © 2010 John Wiley & Sons, Ltd.

  2. ADVERTISING AVOIDANCE PADA IKLAN DI MEDIA TELEVISI

    Directory of Open Access Journals (Sweden)

    Indah Dwi Pratama

    2016-01-01

    Full Text Available One factor that can interfere with the absorption rate of viewers on television advertisement is advertising avoidance which shows the difference between the number of viewers who watch advertisement programs and the number of viewers who watch television programs. The factors that affect advertising avoidance include the demography of the viewers (gender, age, area of residence, and social economic status, or SES, advertising attributes (the television stations, order of ads, genre of the program, and advertising sector, and competition (DayPart. The study attempted to measure the level of advertising avoidance in Indonesia and its relation to various factors that influence it by using the secondary data generated by Nielsen Audience Measurement Indonesia through Television Audience Measurement (TAM. The methods utilized consisted of the t-test independent sample, one way ANOVA, Tukey, Kruskal Wallis, and Dunn Bonferoni. The result showed that the level of advertising avoidance in Indonesia reached by 23%, with relatively similar results to the other studies in various countries. The hypothesis test results also showed a significant relationship between the advertising avoidance and demographic variables, advertising attributes, and competitions affecting this avoidance. On one hand, the findings of the study are expected to be useful for the advertisers to plan their advertisements on television so that they become more effective and efficient. On the other hand, television stations can utilize these findings as a development strategy to expand their audience segmentation and to accommodate the needs of the advertisers more optimally.Keywords: advertising avoidance, television advertisement, TAM, ANOVA, Tukey

  3. Productivity

    DEFF Research Database (Denmark)

    Spring, Martin; Johnes, Geraint; Hald, Kim Sundtoft

    Productivity is increasingly critical for developed economies. It has always been important: as Paul Krugman puts it, “Productivity isn’t everything, but in the long run it is almost everything. A country’s ability to improve its standard of living over time depends almost entirely on its ability...... to raise its output per worker”(Krugman, 1994). Analyses of productivity have, by and large, been the preserve of economists. Operations Management (OM) is rooted in a similar concern for the efficient use of scarce resources; Management Accounting (MA) is concerned with the institutionalised measurement...... and management of productivity. Yet the three perspectives are rarely connected. This paper is a sketch of a literature review seeking to identify, contrast and reconcile these three perspectives. In so doing, it aims to strengthen the connections between policy and managerial analyses of productivity....

  4. Key conclusions from AVOID Work Stream One

    Science.gov (United States)

    Warren, Rachel

    2010-05-01

    AVOID work stream (WS1)one has produced emission scenarios that simulate potential future global emission pathways for greenhouse gases during the 21st century. The study explored the influence of three key features of such pathways: (1) the year in which emissions peak globally, (2) the rate of emission reduction, and (3) the minimum level to which emissions are eventually reduced. It examined the resultant climate change, climate change impacts and economic implications using computer simulations. Avoided impacts, carbon taxes and GDP change increase throughout the 21st century in the models. AVOID-WS1 showed that in the absence of climate policy it is very likely that global mean temperatures would exceed 3 degrees and there are evens chances that the temperature would rise by 4 degrees relative to pre-industrial times. Scenarios that peak emissions in 2016 were more effective at constraining temperatures to below 3 degrees than those that peaked in 2030: one ‘2016' scenario achieved a probability of 45% of avoiding breaching of a 2 degree threshold. Scenarios peaking in 2030 were inconsistent with constraining temperatures to below 2 degrees. Correspondingly, scenarios that peak in 2030 are more effective at avoiding climate impacts than scenarios that peak in 2016, for all sectors that we studied. Hence the date at which emissions peak is more important than the rate of subsequent emissions reduction in determining the avoided impacts. Avoided impacts increase with time, being negligible in the 2030s, significant by the 2050s and large by the 2080s. Finally, the choice of GCM influences the magnitude of the avoided impacts strongly, so that the uncertainties in our estimates of avoided impacts for each scenario are larger than the difference between the scenarios. Our economic analysis is based on models which differ greatly in the assumptions that they make, but generally show that the date at which emissions peak is a stronger driver of induced GDP changes

  5. Disruption avoidance by means of electron cyclotron waves

    International Nuclear Information System (INIS)

    Esposito, B; Granucci, G; Nowak, S; Lazzaro, E; Maraschek, M; Giannone, L; Gude, A; Igochine, V; McDermott, R; Poli, E; Reich, M; Sommer, F; Stober, J; Suttrop, W; Treutterer, W; Zohm, H

    2011-01-01

    Disruptions are very challenging to ITER operation as they may cause damage to plasma facing components due to direct plasma heating, forces on structural components due to halo and eddy currents and the production of runaway electrons. Electron cyclotron (EC) waves have been demonstrated as a tool for disruption avoidance by a large set of recent experiments performed in ASDEX Upgrade and FTU using various disruption types, plasma operating scenarios and power deposition locations. The technique is based on the stabilization of magnetohydrodynamic (MHD) modes (mainly m/n = 2/1) through the localized injection of EC power on the resonant surface. This paper presents new results obtained in ASDEX Upgrade regarding stable operation above the Greenwald density achieved after avoidance of density limit disruptions by means of ECRH and suitable density feedback control (L-mode ohmic plasmas, I p = 0.6 MA, B t = 2.5 T) and NTM-driven disruptions at high-β limit delayed/avoided by means of both co-current drive (co-ECCD) and pure heating (ECRH) with power ≤1.7 MW (H-mode NBI-heated plasmas, P NBI ∼ 7.5 MW, I p = 1 MA, B t = 2.1 T, q 95 ∼ 3.6). The localized perpendicular injection of ECRH/ECCD onto a resonant surface leads to the delay and/or complete avoidance of disruptions. The experiments indicate the existence of a power threshold for mode stabilization to occur. An analysis of the MHD mode evolution using the generalized Rutherford equation coupled to the frequency and phase evolution equations shows that control of the modes is due to EC heating close to the resonant surface. The ECRH contribution (Δ' H term) is larger than the co-ECCD one in the initial and more important phase when the discharge is 'saved'. Future research and developments of the disruption avoidance technique are also discussed.

  6. Flight Deck Weather Avoidance Decision Support: Implementation and Evaluation

    Science.gov (United States)

    Wu, Shu-Chieh; Luna, Rocio; Johnson, Walter W.

    2013-01-01

    Weather related disruptions account for seventy percent of the delays in the National Airspace System (NAS). A key component in the weather plan of the Next Generation of Air Transportation System (NextGen) is to assimilate observed weather information and probabilistic forecasts into the decision process of flight crews and air traffic controllers. In this research we explore supporting flight crew weather decision making through the development of a flight deck predicted weather display system that utilizes weather predictions generated by ground-based radar. This system integrates and presents this weather information, together with in-flight trajectory modification tools, within a cockpit display of traffic information (CDTI) prototype. that the CDTI features 2D and perspective 3D visualization models of weather. The weather forecast products that we implemented were the Corridor Integrated Weather System (CIWS) and the Convective Weather Avoidance Model (CWAM), both developed by MIT Lincoln Lab. We evaluated the use of CIWS and CWAM for flight deck weather avoidance in two part-task experiments. Experiment 1 compared pilots' en route weather avoidance performance in four weather information conditions that differed in the type and amount of predicted forecast (CIWS current weather only, CIWS current and historical weather, CIWS current and forecast weather, CIWS current and forecast weather and CWAM predictions). Experiment 2 compared the use of perspective 3D and 21/2D presentations of weather for flight deck weather avoidance. Results showed that pilots could take advantage of longer range predicted weather forecasts in performing en route weather avoidance but more research will be needed to determine what combinations of information are optimal and how best to present them.

  7. Harm avoidance and disability in old age.

    Science.gov (United States)

    Wilson, Robert S; Buchman, Aron S; Arnold, Steven E; Shah, Raj C; Tang, Yuxiao; Bennett, David A

    2006-01-01

    The relation of personality to disability in old age is not well understood. The authors examined the relation of harm avoidance, a trait indicating a tendency to worry, fear uncertainty, be shy, and tire easily, to disability in a group of 474 older persons without dementia. Participants completed the 35-item Harm Avoidance scale. Disability was assessed with the Rosow-Breslau scale, a self-report measure of physical mobility. Performance-based tests of lower limb functions were also administered from which composite measures of gait, balance, and strength were derived. In a logistic regression model controlled for age, sex, education, and lower limb function, persons with high levels of harm avoidance were nearly three times as likely to report mobility limitations as persons with low levels, and these effects largely reflected fatigability and fear of uncertainty. The association of harm avoidance with disability was not explained or modified by frailty, physical activity, depressive symptoms, neuroticism, extraversion, or cognition. The results suggest that harm avoidance is associated with disability in old age.

  8. Rape avoidance behavior among Slovak women.

    Science.gov (United States)

    Prokop, Pavol

    2013-05-28

    Rape has been a recurrent adaptive problem for many species, including humans. Rape is costly to women in terms of disease transmission, partner abandonment, and unwanted pregnancy (among other costs). Therefore, behavioral strategies which allow women to avoid coercive men may have been favored by selection. In line with this evolutionary reasoning, the current research documented that physically stronger women and those in a committed romantic relationship reported more rape avoidance behavior. In addition, virgin women tended to perform more rape avoidance behavior compared with their non-virgin counterparts. Women with high conception risk perceived themselves as physically stronger, which may protect them against a potential rapist. Fear of unwanted pregnancy from rape decreased as age increased, reflecting higher fertility among younger participants. However, older women reported more rape avoidance behavior, which contradicts evolutionary predictions. The results provide some support for evolutionary hypotheses of rape avoidance behavior which suggest that woman's perception of rape is influenced by parental investment and perceived physical condition.

  9. DNA elasticity: topology of self-avoidance

    International Nuclear Information System (INIS)

    Samuel, Joseph; Sinha, Supurna; Ghosh, Abhijit

    2006-01-01

    We present a theoretical treatment of DNA stretching and twisting experiments, in which we discuss global topological subtleties of self-avoiding ribbons and provide an underlying justification for the worm-like rod chain (WLRC) model proposed by Bouchiat and Mezard. Some theoretical points regarding the WLRC model are clarified: the 'local writhe formula' and the use of an adjustable cut-off parameter to 'regularize' the model. Our treatment brings out the precise relation between the worm-like chain (WLC), the paraxial worm-like chain (PWLC) and the WLRC models. We describe the phenomenon of 'topological untwisting' and the resulting collapse of link sectors in the WLC model and note that this leads to a free energy profile periodic in the applied link. This periodicity disappears when one takes into account the topology of self-avoidance or at large stretch forces (paraxial limit). We note that the difficult non-local notion of self-avoidance can be replaced (in an approximation) by the simpler local notion of 'south avoidance'. This gives an explanation for the efficacy of the approach of Bouchiat and Mezard in explaining the 'hat curves' using the WLRC model, which is a south avoiding model. We propose a new class of experiments to probe the continuous transition between the periodic and aperiodic behaviour of the free energy

  10. A note on the neutrality of profit taxes with tax evasion and tax avoidance

    OpenAIRE

    Che-chiang Huang; Horn-in Kuo

    2014-01-01

    Traditional literature exploring the relationship between production and tax evasion ignores the impact of other activities on these two decisions. This paper incorporates firms' tax avoidance activities into the model of tax evasion. In contrast to conventional results, we find that profit tax is not necessarily neutral. In addition, the independency or separability of tax evasion and production decisions may not hold either whenever tax avoidance is present.

  11. Peer conflict avoidance: associations with loneliness, social anxiety, and social avoidance.

    Science.gov (United States)

    Johnson, H D; LaVoie, J C; Spenceri, M C; Mahoney-Wernli, M A

    2001-02-01

    Failure to resolve peer conflict is associated with children's reports of loneliness, social anxiety, and social avoidance. Although these relationships are well established, researchers have not examined the association between the avoidance of peer conflict and various adjustment characteristics. The current study examined the association between avoidance of conflict and measures of loneliness, social anxiety, and social avoidance for 59 pupils in Grade 4 (31 boys and 28 girls) and 47 in Grade 8 (22 boys and 25 girls). Volunteers indicated that conflict avoidance based on autonomy, e.g., independence issues, and interpersonal issues, e.g., closeness and cohesion, was associated with scores on loneliness for boys and girls, respectively. Conflict avoidance for emotional and physical well-being and fear of punishment was associated with increased reports of loneliness and social anxiety for children in Grade 4.

  12. A Transient Dopamine Signal Represents Avoidance Value and Causally Influences the Demand to Avoid

    Science.gov (United States)

    Pultorak, Katherine J.; Schelp, Scott A.; Isaacs, Dominic P.; Krzystyniak, Gregory

    2018-01-01

    Abstract While an extensive literature supports the notion that mesocorticolimbic dopamine plays a role in negative reinforcement, recent evidence suggests that dopamine exclusively encodes the value of positive reinforcement. In the present study, we employed a behavioral economics approach to investigate whether dopamine plays a role in the valuation of negative reinforcement. Using rats as subjects, we first applied fast-scan cyclic voltammetry (FSCV) to determine that dopamine concentration decreases with the number of lever presses required to avoid electrical footshock (i.e., the economic price of avoidance). Analysis of the rate of decay of avoidance demand curves, which depict an inverse relationship between avoidance and increasing price, allows for inference of the worth an animal places on avoidance outcomes. Rapidly decaying demand curves indicate increased price sensitivity, or low worth placed on avoidance outcomes, while slow rates of decay indicate reduced price sensitivity, or greater worth placed on avoidance outcomes. We therefore used optogenetics to assess how inducing dopamine release causally modifies the demand to avoid electrical footshock in an economic setting. Increasing release at an avoidance predictive cue made animals more sensitive to price, consistent with a negative reward prediction error (i.e., the animal perceives they received a worse outcome than expected). Increasing release at avoidance made animals less sensitive to price, consistent with a positive reward prediction error (i.e., the animal perceives they received a better outcome than expected). These data demonstrate that transient dopamine release events represent the value of avoidance outcomes and can predictably modify the demand to avoid. PMID:29766047

  13. New apparatus for training the avoidance reaction.

    Science.gov (United States)

    Tikal, K

    1988-01-01

    A new apparatus for active avoidance training in rats consists of a short, wide runway which can be tilted from a horizontal to vertical position. One half of the electrifiable grid floor is covered by a nonconducting sheet. For brightness (black-white) discrimination training a white walled goal box can be inserted into the runway and shifted from left to right during training. Avoidance training of 24 rats (female Wistar SPF) required 14.1 +/- 2.6 (mean +/- SEM) to-criterion trials (9/10) and was completed in less than 4 min. Brightness discrimination training required 21.3 +/- 2.1 to-criterion trials and the time of training did not exceed 12 min. The retention of the acquired responses was very good in both cases. The main advantage of the apparatus is very rapid acquisition of the one-way and discriminated avoidance without the necessity of manual manipulation of the animal.

  14. Engaging Math-Avoidant College Students

    Directory of Open Access Journals (Sweden)

    M. Paul Latiolais

    2009-07-01

    Full Text Available This paper is an informal, personal account of how we, as two college teachers, became interested in math anxiety, decided to explore it amongst students at our institution in order to inform our teaching, and became convinced that the massive problem is math avoidance. We tried discussion groups, but few students attended, although those that did made useful suggestions. Thus informed, we designed an innovative course, Confronting College Mathematics as a Humanities course with the possibility of credit toward the math requirement, but it was undersubscribed in its first offering and had to be canceled. How can we get college students who avoid math to break through the barrier of math avoidance? We have now begun to explore a new approach: Second Life, where students can engage math—and quantitative literacy—virtually, and anonymously.

  15. Information Dilemmas and Blame-Avoidance Strategies

    DEFF Research Database (Denmark)

    Erik, Baekkeskov; Rubin, Olivier

    2017-01-01

    from day one about 2009 H1N1 flu. To explore why, this article links crisis information dilemmas to blame avoidance concepts from democratic political theories. We argue that greater Chinese transparency about infectious disease response reflects evolution in blame avoidance, from heavy reliance...... on information control to insulating leaders by using technical experts and agencies as 'lightning rods.' In 2003, the Chinese strategy of information containment and secrecy backfired, and the Chinese leadership eventually received blame at home and internationally for crisis mismanagement. In 2009, China put...... in place public health specialists and institutions as responsible for H1N1 information and responses, thereby insulating the top-tier leadership....

  16. Rewarding peak avoidance: the Dutch 'Spitsmijden' projects

    NARCIS (Netherlands)

    Knockaert, J.; Bakens, J.; Ettema, D.F.; Verhoef, E.

    2011-01-01

    The Dutch road network is becoming increasingly congested. In late 2006, a group of companies, universities and government institutions established the Spitsmijden project. ‘Spitsmijden’ is the Dutch term for ‘avoiding the peak’. This joint initiative aimed to identify and assess a short-term

  17. The Netherlands Bird Avoidance Model, Final Report

    NARCIS (Netherlands)

    Shamoun-Baranes, J.; Bouten, W.; Sierdsema, H.; van Belle, J.; van Gasteren, J.R.; van Loon, E.E.

    2006-01-01

    The NL-BAM was developed as a web-based decision support tool to be used by the bird hazard avoidance experts in the ecology unit of the Royal Netherlands Air Force. The NL-BAM will be used together with the ROBIN 4 radar system to provide BirdTAMS, for real time warnings and flight planning and to

  18. Employer Attitudes towards Peak Hour Avoidance

    NARCIS (Netherlands)

    Vonk Noordegraaf, D.M.; Annema, J.A.

    2012-01-01

    Peak Hour Avoidance is a relatively new Dutch mobility management measure. To reduce congestion frequent car drivers are given a financial reward for reducing the proportion of trips that they make during peak hours on a specific motorway section. Although previous studies show that employers are

  19. Employer attitudes towards peak hour avoidance

    NARCIS (Netherlands)

    Noordegraaf, D.M.V.; Annema, J.A.

    2012-01-01

    Peak Hour Avoidance is a relatively new Dutch mobility management measure. To reduce congestion frequent car drivers are given a financial reward for reducing the proportion of trips that they make during peak hours on a specific motorway section. Although previous studies show that employers are

  20. Avoidance Motivation and Conservation of Energy

    NARCIS (Netherlands)

    Roskes, Marieke; Elliot, Andrew J.; Nijstad, Bernard A.; De Dreu, Carsten K. W.

    Compared to approach motivation, avoidance motivation evokes vigilance, attention to detail, systematic information processing, and the recruitment of cognitive resources. From a conservation of energy perspective it follows that people would be reluctant to engage in the kind of effortful cognitive

  1. Avoidance motivation and conservation of energy

    NARCIS (Netherlands)

    Roskes, Marieke; Elliot, Andrew J.; Nijstad, Bernard A.; De Dreu, Carsten K W

    Compared to approach motivation, avoidance motivation evokes vigilance, attention to detail, systematic information processing, and the recruitment of cognitive resources. From a conservation of energy perspective it follows that people would be reluctant to engage in the kind of effortful cognitive

  2. Pathological Demand Avoidance: Exploring the Behavioural Profile

    Science.gov (United States)

    O'Nions, Elizabeth; Viding, Essi; Greven, Corina U; Ronald, Angelica; Happé, Francesca

    2014-01-01

    "Pathological Demand Avoidance" is a term increasingly used by practitioners in the United Kingdom. It was coined to describe a profile of obsessive resistance to everyday demands and requests, with a tendency to resort to "socially manipulative" behaviour, including outrageous or embarrassing acts. Pathological demand…

  3. ALUMINUM AVOIDANCE BY MUCUNA-PRURIENS

    NARCIS (Netherlands)

    HAIRIAH, K; VANNOORDWIJK, M; STULEN, [No Value; KUIPER, PJC

    The hypothesis was tested that the avoidance of acid subsoil by the velvet bean Mucuna pruriens is based on a mechanism acting on the whole root system rather than on individual roots. In a split-root experiment with circulating nutrient solution the growth of plants with Al-containing (+/+) or

  4. Audit incorporating avoidability and appropriate intervention can ...

    African Journals Online (AJOL)

    Audit incorporating avoidability and appropriate intervention can significantly decrease perinatal mortality. H. R. G. Ward, G. R. Howarth, O. J. N. Jennings,. R. C. Pattinson .... 6 months) and seven interns. The study was .... maternity care notes study: a randomized control trial to assess the effects of giving expectant mothers ...

  5. Hydrofluoric acid on dentin should be avoided.

    NARCIS (Netherlands)

    Loomans, B.A.C.; Mine, A.; Roeters, F.J.M.; Opdam, N.J.M.; Munck, J. De; Huysmans, M.C.D.N.J.M.; Meerbeek, B. Van

    2010-01-01

    Hydrofluoric acid can be used for intra-oral repair of restorations. Contamination of tooth substrate with hydrofluoric acid cannot always be avoided. OBJECTIVES: To investigate the bonding effectiveness to hydrofluoric acid contaminated dentin by, micro-tensile bond strength testing, SEM and TEM.

  6. Women Coping with a Partner's Sexual Avoidance.

    Science.gov (United States)

    Renshaw, Domeena C.

    2001-01-01

    Discusses the complexities of sexual avoidance, or Hypoactive Sexual Desire (HSD), a previously neglected aspect of a couple's relationship. Suggests that learning from a therapist to accept and enjoy other forms of sexual exchange can open up new horizons of physical and emotional intimacy. (Contains 17 references.) (GCP)

  7. Obstacle detection and avoiding of quadcopter

    Science.gov (United States)

    Wang, Dizhong; Lin, Jiajian

    2017-10-01

    Recent years, the flight control technology over quadcopter has been boosted vigorously and acquired the comprehensive application in a variety of industries. However, it is prominent for there to be problems existed in the stable and secure flight with the development of its autonomous flight. Through comparing with the characteristics of ultrasonic ranging and laser Time-of-Flight(abbreviated to ToF) distance as well as vision measurement and its related sensors, the obstacle detection and identification sensors need to be installed in order to effectively enhance the safety flying for aircraft, which is essential for avoiding the dangers around the surroundings. That the major sensors applied to objects perception at present are distance measuring instruments which based on the principle and application of non-contact detection technology . Prior to acknowledging the general principles of flight and obstacle avoiding, the aerodynamics modeling of the quadcopter and its object detection means has been initially determined on this paper. Based on such premise, this article emphasized on describing and analyzing the research on obstacle avoiding technology and its application status, and making an expectation for the trend of its development after analyzing the primary existing problems concerning its accuracy object avoidance.

  8. Traveler's guide to avoiding infectious diseases

    Science.gov (United States)

    ... to-date information, please visit the Centers for Disease Control and Prevention's (CDC) website -- www.cdc.gov/zika . To prevent getting the Zika virus, take steps to avoid mosquito bites. Sexual transmission of the virus can be prevented by using condoms ...

  9. An Examination of Avoided Costs in Utah

    Energy Technology Data Exchange (ETDEWEB)

    Bolinger, Mark; Wiser, Ryan

    2005-01-07

    The Utah Wind Working Group (UWWG) believes there are currently opportunities to encourage wind power development in the state by seeking changes to the avoided cost tariff paid to qualifying facilities (QFs). These opportunities have arisen as a result of a recent renegotiation of Pacificorp's Schedule 37 tariff for wind QFs under 3 MW, as well as an ongoing examination of Pacificorp's Schedule 38 tariff for wind QFs larger than 3 MW. It is expected that decisions made regarding Schedule 38 will also impact Schedule 37. Through the Laboratory Technical Assistance Program (Lab TAP), the UWWG has requested (through the Utah Energy Office) that LBNL provide technical assistance in determining whether an alternative method of calculating avoided costs that has been officially adopted in Idaho would lead to higher QF payments in Utah, and to discuss the pros and cons of this method relative to the methodology recently adopted under Schedule 37 in Utah. To accomplish this scope of work, I begin by summarizing the current method of calculating avoided costs in Utah (per Schedule 37) and Idaho (the ''surrogate avoided resource'' or SAR method). I then compare the two methods both qualitatively and quantitatively. Next I present Pacificorp's four main objections to the use of the SAR method, and discuss the reasonableness of each objection. Finally, I conclude with a few other potential considerations that might add value to wind QFs in Utah.

  10. Approach and avoidance in fear of spiders

    NARCIS (Netherlands)

    Rinck, M.; Becker, E.S.

    2007-01-01

    We examined attitudes towards spiders by employing an Approach-Avoidance Task, in which participants respond to pictures by pulling a joystick towards themselves or by pushing it away from themselves. For spider fearfuls, this stimulus–response assignment is either compatible (push spiders away) or

  11. FORUM Achieving weight loss and avoiding obesity

    African Journals Online (AJOL)

    The efficacy of diets advocating extreme macronutrient manipulation has been reviewed extensively. Studies involving participation for 12 months or longer revealed that diet adherence, length of intervention and level of calorie. ISSUES IN MEDICINE. Achieving weight loss and avoiding obesity. Maria Elizabeth Catsicas.

  12. Learn to Avoid or Overcome Leadership Obstacles

    Science.gov (United States)

    D'Auria, John

    2015-01-01

    Leadership is increasingly recognized as an important factor in moving schools forward, yet we have been relatively random in how we prepare and support them. Four obstacles often block or diminish their effectiveness. Avoiding or overcoming each of these requires an underlying set of skills and knowledge that we believe can be learned and…

  13. PENGARUH CORPORATE GOVERNANCE TERHADAP TAX AVOIDANCE

    Directory of Open Access Journals (Sweden)

    Nuralifmida Ayu Annisa

    2012-05-01

    Full Text Available This study aims to find out how the influence of the corporate governance of tax avoidanceactivity in companies listed on Indonesia Stock Exchange in 2008. The samples are publiclytraded company listed on the Indonesia Stock Exchange in 2008 as many as 200 companies. Thisstudy uses data analysis and regression analysis of the elements of corporate governance and taxavoidance. The results of this study show that the elements of corporate governance that consist ofaudit quality and audit committee significantly influence the activity of tax avoidance as measuredusing proxy book tax gap. Other results show that the tax avoidance activity as measured withproxy book tax gap are not affected significantly by institutional ownership and board ofcommissioners. Limitation of this study is not to use each type of industries as control variable socan’t identify the direct effect from type of industry on tax avoidance. Another limitation of thisstudy is use corporate governance’s proxy separately, so it can’t capture the full effect ofcorporate governance. Keywords:corporate governance, ownership structure, board of commissioners, audit committee,tax avoidance, book tax gap.

  14. Avoidance: From threat encounter to action execution

    NARCIS (Netherlands)

    Arnaudova, I.

    2015-01-01

    Every day we encounter many threats to survival: a car speeding on a small street or an angry neighbor carrying an axe. Mostly, people go through their days not worrying that their chance of survival might be small. They avoid many dangers without even thinking about them (e.g., looking at both

  15. Wake Vortex Avoidance System and Method

    Science.gov (United States)

    Shams, Qamar A. (Inventor); Zuckerwar, Allan J. (Inventor); Knight, Howard K. (Inventor)

    2017-01-01

    A wake vortex avoidance system includes a microphone array configured to detect low frequency sounds. A signal processor determines a geometric mean coherence based on the detected low frequency sounds. A display displays wake vortices based on the determined geometric mean coherence.

  16. Reasonable Avoidability, Responsibility and Lifestyle Diseases

    DEFF Research Database (Denmark)

    Andersen, Martin Marchman

    2012-01-01

    In “Health, Luck and Justice” Shlomi Segall argues for a luck egalitarian approach to justice in health care. As the basis for a just distribution he suggests a principle of Reasonable Avoidability, which he takes to imply that we do not have justice-based reasons to treat diseases brought about...

  17. Simple Obstacle Avoidance Algorithm for Rehabilitation Robots

    NARCIS (Netherlands)

    Stuyt, Floran H.A.; Römer, GertWillem R.B.E.; Stuyt, Harry .J.A.

    2007-01-01

    The efficiency of a rehabilitation robot is improved by offering record-and-replay to operate the robot. While automatically moving to a stored target (replay) collisions of the robot with obstacles in its work space must be avoided. A simple, though effective, generic and deterministic algorithm

  18. Avoidable cancers in the Nordic countries. Occupation

    DEFF Research Database (Denmark)

    Dreyer, L; Andersen, A; Pukkala, E

    1997-01-01

    around the year 2000, with 1,890 among men and fewer than 25 among women. The proportions that could be avoided if industrial carcinogens were eliminated would be 70% of mesotheliomas, 20% of cancers of the nasal cavity and sinuses, 12% of lung cancers, 5% of laryngeal cancers, 2% of urinary bladder...

  19. Myopic Regret Avoidance: Feedback Avoidance and Learning in Repeated Decision Making

    Science.gov (United States)

    Reb, Jochen; Connolly, Terry

    2009-01-01

    Decision makers can become trapped by "myopic regret avoidance" in which rejecting feedback to avoid short-term "outcome regret" (regret associated with counterfactual outcome comparisons) leads to reduced learning and greater long-term regret over continuing poor decisions. In a series of laboratory experiments involving repeated choices among…

  20. A collision avoidance model for two-pedestrian groups: Considering random avoidance patterns

    Science.gov (United States)

    Zhou, Zhuping; Cai, Yifei; Ke, Ruimin; Yang, Jiwei

    2017-06-01

    Grouping is a common phenomenon in pedestrian crowds and group modeling is still an open challenging problem. When grouping pedestrians avoid each other, different patterns can be observed. Pedestrians can keep close with group members and avoid other groups in cluster. Also, they can avoid other groups separately. Considering this randomness in avoidance patterns, we propose a collision avoidance model for two-pedestrian groups. In our model, the avoidance model is proposed based on velocity obstacle method at first. Then grouping model is established using Distance constrained line (DCL), by transforming DCL into the framework of velocity obstacle, the avoidance model and grouping model are successfully put into one unified calculation structure. Within this structure, an algorithm is developed to solve the problem when solutions of the two models conflict with each other. Two groups of bidirectional pedestrian experiments are designed to verify the model. The accuracy of avoidance behavior and grouping behavior is validated in the microscopic level, while the lane formation phenomenon and fundamental diagrams is validated in the macroscopic level. The experiments results show our model is convincing and has a good expansibility to describe three or more pedestrian groups.

  1. Measuring Patients’ Attachment Avoidance in Psychotherapy: Development of the Attachment Avoidance in Therapy Scale (AATS

    Directory of Open Access Journals (Sweden)

    András Láng

    2012-11-01

    Full Text Available A new scale measuring patient-therapist attachment avoidance was developed. Attachment Avoidance in Therapy Scale is a new measure based on the Bartholomew model of adult attachment (Bartholomew & Horowitz, 1991 and the Experience in Close Relationships Scale (Brennan, Clark, & Shaver, 1998 to measure patients’ attachment avoidance towards therapists. With 112 patient-therapist dyads participating in the study, validation of a preliminary scale – measuring both attachment anxiety and attachment avoidance in therapy – took place using therapists’ evaluations of patients’ relational behavior and patients’ self-reports about their attitude toward psychotherapy. Analysis of the data revealed six underlying scales. Results showed all six scales to be reliable. Validation of scales measuring attachment anxiety failed. The importance of Attachment Avoidance in Therapy Scale and its subscales is discussed.

  2. Bursting neurons and ultrasound avoidance in crickets

    Directory of Open Access Journals (Sweden)

    Gary eMarsat

    2012-07-01

    Full Text Available Decision making in invertebrates often relies on simple neural circuits composed of only a few identified neurons. The relative simplicity of these circuits makes it possible to identify the key computation and neural properties underlying decisions. In this review, we summarize recent research on the neural basis of ultrasound avoidance in crickets, a response that allows escape from echolocating bats. The key neural property shaping behavioral output is high-frequency bursting of an identified interneuron, AN2, which carries information about ultrasound stimuli from receptor neurons to the brain. AN2's spike train consists of clusters of spikes –bursts– that may be interspersed with isolated, non-burst spikes. AN2 firing is necessary and sufficient to trigger avoidance steering but only high-rate firing, such as occurs in bursts, evokes this response. AN2 bursts are therefore at the core of the computation involved in deciding whether or not to steer away from ultrasound. Bursts in AN2 are triggered by synaptic input from nearly synchronous bursts in ultrasound receptors. Thus the population response at the very first stage of sensory processing –the auditory receptor- already differentiates the features of the stimulus that will trigger a behavioral response from those that will not. Adaptation, both intrinsic to AN2 and within ultrasound receptors, scales the burst-generating features according to the stimulus statistics, thus filtering out background noise and ensuring that bursts occur selectively in response to salient peaks in ultrasound intensity. Furthermore AN2’s sensitivity to ultrasound varies adaptively with predation pressure, through both developmental and evolutionary mechanisms. We discuss how this key relationship between bursting and the triggering of avoidance behavior is also observed in other invertebrate systems such as the avoidance of looming visual stimuli in locusts or heat avoidance in beetles.

  3. Determination of neutron resonance parameters of Neptunium 237 between 0 and 500 eV. The covariance matrices of statistical and of systematic origin, relating the resonance parameters, are also given

    International Nuclear Information System (INIS)

    Lepretre, A.; Herault, N.; Brusegan, A.; Noguere, G.; Siegler, P.

    2002-12-01

    This report is a follow up of the report CEA DAPNIA/SPHN-99-04T of Vincent Gressier. In the frame of a collaboration between the 'Commissariat a l'Energie Atomique (CEA)' and the Institute for Reference Materials and Measurement (IRMM, Geel, Belgique), the resonance parameters of neptunium 237 have been determined in the energy interval between 0 and 500 eV. These parameters have been obtained by using the Refit code in analysing simultaneously three transmission experiments. The covariance matrix of statistical origin is provided. A new method, based on various sensitivity studies is proposed for determining also the covariance matrix of systematic origin, relating the resonance parameters. From an experimental viewpoint, the study indicated that, with a large probability, the background spectrum has structure. A two dimensional profiler for the neutron density has been proved feasible. Such a profiler could, among others, demonstrate the existence of the structured background. (authors)

  4. Environmental triggers and avoidance in the management of asthma

    Directory of Open Access Journals (Sweden)

    Gautier C

    2017-03-01

    Full Text Available Clarisse Gautier,1 Denis Charpin1,2 1Department of Pulmonology and Allergy, North Hospital, 2Faculty of Medicine, Aix-Marseille University, Marseille, France Abstract: Identifying asthma triggers forms the basis of environmental secondary prevention. These triggers may be allergenic or nonallergenic. Allergenic triggers include indoor allergens, such as house dust mites (HDMs, molds, pets, cockroaches, and rodents, and outdoor allergens, such as pollens and molds. Clinical observations provide support for the role of HDM exposure as a trigger, although avoidance studies provide conflicting results. Molds and their metabolic products are now considered to be triggers of asthma attacks. Pets, dogs, and especially cats can undoubtedly trigger asthmatic symptoms in sensitized subjects. Avoidance is difficult and rarely adhered to by families. Cockroach allergens contribute to asthma morbidity, and avoidance strategies can lead to clinical benefit. Mouse allergens are mostly found in inner-city dwellings, but their implication in asthma morbidity is debated. In the outdoors, pollens can induce seasonal asthma in sensitized individuals. Avoidance relies on preventing pollens from getting into the house and on minimizing seasonal outdoor exposure. Outdoor molds may lead to severe asthma exacerbations. Nonallergenic triggers include viral infections, active and passive smoking, meteorological changes, occupational exposures, and other triggers that are less commonly involved. Viral infection is the main asthma trigger in children. Active smoking is associated with higher asthma morbidity, and smoking cessation interventions should be personalized. Passive smoking is also a risk factor for asthma exacerbation. The implementation of public smoking bans has led to a reduction in the hospitalization of asthmatic children. Air pollution levels have been linked with asthmatic symptoms, a decrease in lung function, and increased emergency room visits and

  5. Research on embedded automobile collision avoidance system

    Directory of Open Access Journals (Sweden)

    TAO Feng

    2016-08-01

    Full Text Available Taking ARM embedded Linux operating system as the development platform,combined with AVR microcontroller,while optimizing the ranging algorithm and using air ultrasonic transducer,the measurement range of which can be up to 50 meter,this paper designs a high-precision,range far,low price,various models suitable automobile collision avoidance warning system.The system adopts Forlinx OK6410 development board for the master.AVR microcontroller is responsible for taking the data of traveling distance between vehicles,and with the ARM development board via RS232 communication transfers vehicle′s distance and speed information to the ARM development boards.The system uses the established collision avoidance model to get alarm information.Experiments show that the system can accurately send out alarm information within a certain range.It is innovative and practical.

  6. How to avoid deferred-compensation troubles.

    Science.gov (United States)

    Freeman, Todd I

    2005-06-01

    Executive compensation packages have long included stock options and deferred compensation plans in order to compete for talent. Last year, Congress passed a law in response to the Enron debacle, in which executives were perceived to be protecting their deferred compensation at the expense of employees, creditors, and investors. The new law is designed to protect companies and their shareholders from being raided by the very executives that guided the company to financial ruin. Physicians who are part owners of medical practices need to know about the changes in the law regarding deferred compensation and how to avoid costly tax penalties. This article discusses how the changes affect medical practices as well as steps physician-owned clinics can take to avoid the risk of penalty, such as freezing deferred compensation and creating a new deferred compensation plan.

  7. Avoidant Personality Disorder: a Current Review.

    Science.gov (United States)

    Weinbrecht, Anna; Schulze, Lars; Boettcher, Johanna; Renneberg, Babette

    2016-03-01

    This review focuses on recent research on diagnostic aspects, etiology, and treatment of avoidant personality disorder (AVPD). Current studies stress the close relation between AVPD and social anxiety disorder, the influence of genetic factors in the development of AVPD, and the relative stability of symptoms. Treatment approaches should target the pervasive patterns of social inhibition, feelings of inadequacy, and hypersensitivity to negative evaluation. Empirical evidence for cognitive-behavior and schema therapy is promising. Few other therapeutic approaches have been developed, but until now, these have only been investigated in case studies. We conclude that AVPD qualifies as a neglected disorder and that more research specifically on avoidant personality disorder symptoms and its treatment is needed.

  8. Optical Flow based Robot Obstacle Avoidance

    Directory of Open Access Journals (Sweden)

    Kahlouche Souhila

    2008-11-01

    Full Text Available In this paper we try to develop an algorithm for visual obstacle avoidance of autonomous mobile robot. The input of the algorithm is an image sequence grabbed by an embedded camera on the B21r robot in motion. Then, the optical flow information is extracted from the image sequence in order to be used in the navigation algorithm. The optical flow provides very important information about the robot environment, like: the obstacles disposition, the robot heading, the time to collision and the depth. The strategy consists in balancing the amount of left and right side flow to avoid obstacles, this technique allows robot navigation without any collision with obstacles. The robustness of the algorithm will be showed by some examples.

  9. Construction dispute research conceptualisation, avoidance and resolution

    CERN Document Server

    2014-01-01

    There are three specific purposes of Construction Dispute Research. First, this volume aims to summarise studies on construction dispute. Second, apart from the theoretical constructs, where appropriate empirical tests are also included. This approach serves to go beyond the commonly used anecdotal approach for the subject matters. Third, it is the sincere hope of the authors that this book will help shaping research agenda of construction dispute.  The studies are mostly framed from a management perspective drawing on methods and concepts in contract law, economics, psychology and management science.   The book has twenty chapters that are arranged in four parts covering conceptualisation, avoidance, negotiation and mediation. Part 1 is devoted for dispute conceptualisation. A building is only as strong as its foundation. Thus it is no better start to study construction dispute by conceptualisation. The theme of Part 2 is dispute avoidance. The conventional wisdom of ‘prevention is better than cure’ se...

  10. UV Impacts Avoided by the Montreal Protocol

    Science.gov (United States)

    Newman, Paul; McKenzie, Richard

    2010-01-01

    Temporal and geographical variabilities in the future "World Expected" UV environment are compared with the "World Avoided", which would have occurred without the Montreal Protocol on protection of the ozone layer and its subsequent amendments and adjustments. Based on calculations of clear-sky UV irradiances, the effects of the Montreal Protocol have been hugely beneficial to avoid the health risks, such as skin cancer, which are associated with high UV, while there is only a small increase in health risks, such as vitamin D deficiency, that are associated with low UV. However, interactions with climate change may lead to changes in cloud and albedo, and possibly behavioural changes which could also be important.

  11. Moessbauer spectroscopy in neptunium compounds

    Energy Technology Data Exchange (ETDEWEB)

    Nakamoto, Tadahiro; Nakada, Masami; Masaki, Nobuyuki; Saeki, Masakatsu [Japan Atomic Energy Research Inst., Tokyo (Japan)

    1997-03-01

    Moessbauer effects are observable in seven elements of actinides from {sup 232}Th to {sup 247}Cm and Moesbauer spectra have been investigated mainly with {sup 237}Np and {sup 238}U for the reasons of availability and cost of materials. This report describes the fundamental characteristics of Moessbauer spectra of {sup 237}Np and the correlation between the isomer shift and the coordination number of Np(V) compounds. The isomer shifts of Np(V) compounds had a tendency to increase as an increase of coordination number and the isomer shifts of Np(V) compounds showed broad distribution as well as those of Np(VI) but {delta} values of the compounds with the same coordination number were distributed in a narrow range. The {delta} values of Np(VI) complexes with O{sub x} donor set suggest that the Np atom in its hydroxide (NpO{sub 2}(OH){center_dot}4H{sub 2}O)might have pentagonal bipyramidal structure and at least, pentagonal and hexagonal bipyramidal structures might coexist in its acetate and benzoate. Really, such coexistence has been demonstrated in its nitrate, (NpO{sub 2}){sub 2}(NO{sub 3}){sub 2}{center_dot}5H{sub 2}O. (M.N.)

  12. Online Learning of Commission Avoidant Portfolio Ensembles

    OpenAIRE

    Uziel, Guy; El-Yaniv, Ran

    2016-01-01

    We present a novel online ensemble learning strategy for portfolio selection. The new strategy controls and exploits any set of commission-oblivious portfolio selection algorithms. The strategy handles transaction costs using a novel commission avoidance mechanism. We prove a logarithmic regret bound for our strategy with respect to optimal mixtures of the base algorithms. Numerical examples validate the viability of our method and show significant improvement over the state-of-the-art.

  13. Detect and Avoid (DAA) Automation Maneuver Study

    Science.gov (United States)

    2017-02-01

    GUY A. FRENCH JOSEPH C. PRICE, MAJ, USAF Work Unit Manager Acting Chief, Supervisory Control and Cognition Branch Supervisory Control and Cognition...19a. NAME OF RESPONSIBLE PERSON (Monitor) a. REPORT Unclassified b. ABSTRACT Unclassified c. THIS PAGE Unclassified Guy French 19b. TELEPHONE...the ability to detect and safely avoid other aircraft in flight ( Cook & Davis, 2013). In order to increase UAS flight safety and support UAS

  14. Tax avoidance: Definition and prevention issues

    Directory of Open Access Journals (Sweden)

    Anđelković Mileva

    2014-01-01

    Full Text Available The problem of resolving issues pertaining to tax avoidance, and particularly its aggressive forms, has been the focal point of discussion among tax scholars which is increasingly gaining attention of politicians alike. As opposed to tax evasion (which is illegal, the phenomenon of tax avoidance calls for careful consideration of state fiscal interests and a highly precise demarcation of the thin line between the acceptable and unacceptable conduct. In many contemporary states, tax avoidance (which implies a formal behaviour of tax payers within the limits of tax legislation but contrary to the tax regulation objectives is declared to be illegitimate. State authorities do not want to tolerate such activity, which results in tax payers' reduction or avoidance of tax liabilities. We should also bear in mind that all tax payers have the tax planning option at their disposal, by means of which they make sure that they do not pay more tax than they are legally obliged to. However, in case they skilfully use the tax regulation flaws and loopholes for the sole purpose of tax evasion, and/or resort to misrepresentation and deceptive constructs, they are considered to be exceeding the limits of acceptable tax behaviour. In comparison to the specific anti-abuse measures which have been built into some national tax legislations, there is a growing number of states that introduce the general anti-abuse legislations, which is based on judicial doctrines or statutory legislation. Yet, there is a notable difference among the envisaged anti-abuse measures depending on whether the national legislation is based on the Anglo-American or European-Continental legal system. The efficiency of applying these general anti-abuse rules in taxation largely rests on their interpretation as well as on their relationship with the principle of legality.

  15. Avoiding Local Optima with Interactive Evolutionary Robotics

    Science.gov (United States)

    2012-07-09

    the top of a flight of stairs selects for climbing ; suspending the robot and the target object above the ground and creating rungs between the two will...REPORT Avoiding Local Optimawith Interactive Evolutionary Robotics 14. ABSTRACT 16. SECURITY CLASSIFICATION OF: The main bottleneck in evolutionary... robotics has traditionally been the time required to evolve robot controllers. However with the continued acceleration in computational resources, the

  16. The International Double Taxation – Avoiding Methods

    OpenAIRE

    Nicoleta Barbuta-Misu

    2009-01-01

    The paper presents the main causes that determine double taxation, its forms, i.e. the economicdouble taxation and the international legal double taxation, the need for eliminating the double taxation andavoiding methods. In the presentation of the avoidance methods have been used practical examples forcomparison of the tax advantages for income beneficiary between: the total exemption method andprogressive exemption method, on the one hand, and total crediting method and ordinary crediting m...

  17. Functional neuroimaging of avoidance habits in OCD

    Science.gov (United States)

    Gillan, Claire M; Apergis-Schoute, Annemieke M; Morein-Zamir, Sharon; Urcelay, Gonzalo P; Sule, Akeem; Fineberg, Naomi A; Sahakian, Barbara J; Robbins, Trevor W

    2016-01-01

    Objective The goal of this study was to determine the neural correlates of excessive habit formation in obsessive-compulsive disorder (OCD). We aimed to (i) test for neurobiological convergence with the known pathophysiology of OCD and (ii) infer, based on abnormalities in brain activation, whether these habits arise from dysfunction in the goal-directed or habit system. Method Thirty-seven OCD patients and 33 controls learned to avoid shocks while undergoing a functional Magnetic Resonance Imaging (fMRI) scan. Following 4 blocks of training, we tested if the avoidance response had become a habit by removing the threat of shock and measuring continued avoidance. We tested for task-related differences in brain activity in 3 ROIs, the caudate, putamen and medial orbitofrontal cortex at a statistical threshold of phabit formation in OCD patients, which was associated with hyper-activation in the caudate. Activation in this region was also associated with subjective ratings of increased urge to perform habits. The OCD group, as a whole, showed hyper-activation in the medial orbitofrontal cortex (mOFC) during the acquisition of avoidance, however this did not relate directly to habit formation. Conclusions OCD patients exhibited excessive habits that were associated with hyper-activation in a key region implicated in the pathophysiology of OCD, the caudate nucleus. Prior studies suggest that this region is important for goal-directed behavior, suggesting that habit-forming biases in OCD may be a result of impairments in this system, rather than differences in the build up of stimulus-response habits themselves. PMID:25526600

  18. Airborne Collision Detection and Avoidance for Small UAS Sense and Avoid Systems

    Science.gov (United States)

    Sahawneh, Laith Rasmi

    The increasing demand to integrate unmanned aircraft systems (UAS) into the national airspace is motivated by the rapid growth of the UAS industry, especially small UAS weighing less than 55 pounds. Their use however has been limited by the Federal Aviation Administration regulations due to collision risk they pose, safety and regulatory concerns. Therefore, before civil aviation authorities can approve routine UAS flight operations, UAS must be equipped with sense-and-avoid technology comparable to the see-and-avoid requirements for manned aircraft. The sense-and-avoid problem includes several important aspects including regulatory and system-level requirements, design specifications and performance standards, intruder detecting and tracking, collision risk assessment, and finally path planning and collision avoidance. In this dissertation, our primary focus is on developing an collision detection, risk assessment and avoidance framework that is computationally affordable and suitable to run on-board small UAS. To begin with, we address the minimum sensing range for the sense-and-avoid (SAA) system. We present an approximate close form analytical solution to compute the minimum sensing range to safely avoid an imminent collision. The approach is then demonstrated using a radar sensor prototype that achieves the required minimum sensing range. In the area of collision risk assessment and collision prediction, we present two approaches to estimate the collision risk of an encounter scenario. The first is a deterministic approach similar to those been developed for Traffic Alert and Collision Avoidance (TCAS) in manned aviation. We extend the approach to account for uncertainties of state estimates by deriving an analytic expression to propagate the error variance using Taylor series approximation. To address unanticipated intruders maneuvers, we propose an innovative probabilistic approach to quantify likely intruder trajectories and estimate the probability of

  19. Granting silence to avoid wireless collisions

    KAUST Repository

    Choi, Jung Il; Jain, Mayank; Kazandjieva, Maria A.; Levis, Philip

    2010-01-01

    We describe grant-to-send, a novel collision avoidance algorithm for wireless mesh networks. Rather than announce packets it intends to send, a node using grant-to-send announces packets it expects to hear others send. We present evidence that inverting collision avoidance in this way greatly improves wireless mesh performance. Evaluating four protocols from 802.11 meshes and 802.15.4 sensor networks, we find that grant-to-send matches or outperforms CSMA and RTS/CTS in all cases. For example, in a 4-hop UDP flow, grantto- send can achieve 96% of the theoretical maximum throughput while maintaining a 99.9% packet delivery ratio. Grant-tosend is also general enough to replace protocol-specific collision avoidance mechanisms common to sensor network protocols. Grant-to-send is simple. For example, incorporating it into 802.11 requires only 11 lines of driver code and no hardware changes. Furthermore, as it reuses existing 802.11 mechanisms, grant-to-send inter-operates with current networks and can be incrementally deployed. © 2010 IEEE.

  20. Granting silence to avoid wireless collisions

    KAUST Repository

    Choi, Jung Il

    2010-10-01

    We describe grant-to-send, a novel collision avoidance algorithm for wireless mesh networks. Rather than announce packets it intends to send, a node using grant-to-send announces packets it expects to hear others send. We present evidence that inverting collision avoidance in this way greatly improves wireless mesh performance. Evaluating four protocols from 802.11 meshes and 802.15.4 sensor networks, we find that grant-to-send matches or outperforms CSMA and RTS/CTS in all cases. For example, in a 4-hop UDP flow, grantto- send can achieve 96% of the theoretical maximum throughput while maintaining a 99.9% packet delivery ratio. Grant-tosend is also general enough to replace protocol-specific collision avoidance mechanisms common to sensor network protocols. Grant-to-send is simple. For example, incorporating it into 802.11 requires only 11 lines of driver code and no hardware changes. Furthermore, as it reuses existing 802.11 mechanisms, grant-to-send inter-operates with current networks and can be incrementally deployed. © 2010 IEEE.

  1. Traffic jam driving with NMV avoidance

    Science.gov (United States)

    Milanés, Vicente; Alonso, Luciano; Villagrá, Jorge; Godoy, Jorge; de Pedro, Teresa; Oria, Juan P.

    2012-08-01

    In recent years, the development of advanced driver assistance systems (ADAS) - mainly based on lidar and cameras - has considerably improved the safety of driving in urban environments. These systems provide warning signals for the driver in the case that any unexpected traffic circumstance is detected. The next step is to develop systems capable not only of warning the driver but also of taking over control of the car to avoid a potential collision. In the present communication, a system capable of autonomously avoiding collisions in traffic jam situations is presented. First, a perception system was developed for urban situations—in which not only vehicles have to be considered, but also pedestrians and other non-motor-vehicles (NMV). It comprises a differential global positioning system (DGPS) and wireless communication for vehicle detection, and an ultrasound sensor for NMV detection. Then, the vehicle's actuators - brake and throttle pedals - were modified to permit autonomous control. Finally, a fuzzy logic controller was implemented capable of analyzing the information provided by the perception system and of sending control commands to the vehicle's actuators so as to avoid accidents. The feasibility of the integrated system was tested by mounting it in a commercial vehicle, with the results being encouraging.

  2. Knowing and avoiding plagiarism during scientific writing.

    Science.gov (United States)

    Kumar, P Mohan; Priya, N Swapna; Musalaiah, Svvs; Nagasree, M

    2014-09-01

    Plagiarism has become more common in both dental and medical communities. Most of the writers do not know that plagiarism is a serious problem. Plagiarism can range from simple dishonesty (minor copy paste/any discrepancy) to a more serious problem (major discrepancy/duplication of manuscript) when the authors do cut-copy-paste from the original source without giving adequate credit to the main source. When we search databases like PubMed/MedLine there is a lot of information regarding plagiarism. However, it is still a current topic of interest to all the researchers to know how to avoid plagiarism. It's time to every young researcher to know ethical guidelines while writing any scientific publications. By using one's own ideas, we can write the paper completely without looking at the original source. Specific words from the source can be added by using quotations and citing them which can help in not only supporting your work and amplifying ideas but also avoids plagiarism. It is compulsory to all the authors, reviewers and editors of all the scientific journals to know about the plagiarism and how to avoid it by following ethical guidelines and use of plagiarism detection software while scientific writing.

  3. Knowing and Avoiding Plagiarism During Scientific Writing

    Science.gov (United States)

    Kumar, P Mohan; Priya, N Swapna; Musalaiah, SVVS; Nagasree, M

    2014-01-01

    Plagiarism has become more common in both dental and medical communities. Most of the writers do not know that plagiarism is a serious problem. Plagiarism can range from simple dishonesty (minor copy paste/any discrepancy) to a more serious problem (major discrepancy/duplication of manuscript) when the authors do cut-copy-paste from the original source without giving adequate credit to the main source. When we search databases like PubMed/MedLine there is a lot of information regarding plagiarism. However, it is still a current topic of interest to all the researchers to know how to avoid plagiarism. It's time to every young researcher to know ethical guidelines while writing any scientific publications. By using one's own ideas, we can write the paper completely without looking at the original source. Specific words from the source can be added by using quotations and citing them which can help in not only supporting your work and amplifying ideas but also avoids plagiarism. It is compulsory to all the authors, reviewers and editors of all the scientific journals to know about the plagiarism and how to avoid it by following ethical guidelines and use of plagiarism detection software while scientific writing. PMID:25364588

  4. Urban water restrictions: Attitudes and avoidance

    Science.gov (United States)

    Cooper, Bethany; Burton, Michael; Crase, Lin

    2011-12-01

    In most urban cities across Australia, water restrictions remain the dominant policy mechanism to restrict urban water consumption. The extensive adoption of water restrictions as a means to limit demand, over several years, means that Australian urban water prices have consistently not reflected the opportunity cost of water. Given the generally strong political support for water restrictions and the likelihood that they will persist for some time, there is value in understanding households' attitudes in this context. More specifically, identifying the welfare gains associated with avoiding urban water restrictions entirely would be a nontrivial contribution to our knowledge and offer insights into the benefits of alternative policy responses. This paper describes the results from a contingent valuation study that investigates consumers' willingness to pay to avoid urban water restrictions. Importantly, the research also investigates the influence of cognitive and exogenous dimensions on the utility gain associated with avoiding water restrictions. The results provide insights into the impact of the current policy mechanism on economic welfare.

  5. Predictable and avoidable: What’s next?

    Directory of Open Access Journals (Sweden)

    Ivo Pezzuto

    2014-09-01

    Full Text Available The author of this paper (Dr. Ivo Pezzuto has been one of the first authors to write back in 2008 about the alleged "subprime mortgage loans fraud" which has triggered the 2008 financial crisis, in combination with multiple other complex, highly interrelated, and concurrent factors. The author has been also one of the first authors to report in that same working paper of 2008 (available on SSRN and titled "Miraculous Financial Engineering or Toxic Finance? The Genesis of the U.S. Subprime Mortgage Loans Crisis and its Consequences on the Global Financial Markets and Real Economy" the high probability of a Eurozone debt crisis, due to a number of unsolved structural macroeconomic problems, the lack of a single crisis resolution scheme, current account imbalances, and in some countries, housing bubbles/high private debt. In the book published in 2013 and titled "Predictable and Avoidable: Repairing Economic Dislocation and Preventing the Recurrence of Crisis", Dr. Ivo Pezzuto has exposed the root causes of the financial crisis in order to enables readers to understand that the crisis we have seen was predictable and should have been avoidable, and that a recurrence can be avoided, if lessons are learned and the right action taken. Almost one year after the publication of the book "Predictable and Avoidable: Repairing Economic Dislocation and Preventing the Recurrence of Crisis", the author has decided to write this working paper to explore what happened in the meantime to the financial markets and to the financial regulation implementation. Most of all, the author with this working paper aims to provide an updated analysis as strategist and scenario analyst on the topics addressed in the book "Predictable and Avoidable" based on a forward-looking perspective and on potential "tail risk" scenarios. The topics reported in this paper relate to financial crises; Government policy; financial regulation; corporate governance; credit risk management

  6. See-and-Avoid Collision Avoidance Using ADS-B Signal and Radar Sensing, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — IAI proposes an innovative collision avoidance radar and communication technology to detect and track both cooperative and non-cooperative targets. The system...

  7. Disrupted avoidance learning in functional neurological disorder: Implications for harm avoidance theories

    Directory of Open Access Journals (Sweden)

    Laurel S. Morris

    Full Text Available Background: Functional neurological disorder (FND is an elusive disorder characterized by unexplained neurological symptoms alongside aberrant cognitive processing and negative affect, often associated with amygdala reactivity. Methods: We examined the effect of negative conditioning on cognitive function and amygdala reactivity in 25 FND patients and 20 healthy volunteers (HV. Participants were first conditioned to stimuli paired with negative affective or neutral (CS+/CS− information. During functional MRI, subjects then performed an instrumental associative learning task to avoid monetary losses in the context of the previously conditioned stimuli. We expected that FND patients would be better at learning to avoid losses when faced with negatively conditioned stimuli (increased harm avoidance. Multi-echo resting state fMRI was also collected from the same subjects and a robust denoising method was employed, important for removing motion and physiological artifacts. Results: FND subjects were more sensitive to the negative CS+ compared to HV, demonstrated by a reinforcement learning model. Contrary to expectation, FND patients were generally more impaired at learning to avoid losses under both contexts (CS+/CS−, persisting to choose the option that resulted in a negative outcome demonstrated by both behavioural and computational analyses. FND patients showed enhanced amygdala but reduced dorsolateral prefrontal cortex responses when they received negative feedback. Patients also had increased resting state functional connectivity between these two regions. Conclusions: FND patients had impaired instrumental avoidance learning, findings that parallel previous observations of impaired action-outcome binding. FND patients further show enhanced behavioural and neural sensitivity to negative information. However, this did not translate to improved avoidance learning. Put together, our findings do not support the theory of harm avoidance in FND

  8. A Crowd Avoidance Method Using Circular Avoidance Path for Robust Person Following

    Directory of Open Access Journals (Sweden)

    Kohei Morishita

    2017-01-01

    Full Text Available A life-support service robot must avoid both static and dynamic obstacles for working in a real environment. Here, a static obstacle means an obstacle that does not move, and a dynamic obstacle is the one that moves. Assuming the robot is following a target person, we discuss how the robot avoids a crowd through which the target person passes and arrives at the target position. The purpose of this paper is to propose a crowd avoidance method that makes a robot to be able to avoid both static and dynamic obstacles. The method uses the surface points of the obstacles to form an avoidance region, and the robot moves along the edge of the region. We conducted experiments assuming various situations such that the robot was blocked, there was a wide gap in the crowd, or a person in the crowd yielded for the robot to pass through. As an experimental result, it was confirmed the robot could avoid the crowd even when the obstacles were aligned in an “inverted wedge” shape.

  9. Avoiding Plagiarism in Writing a Research Paper

    Directory of Open Access Journals (Sweden)

    Majid Wajdi

    2018-03-01

    Full Text Available This paper discusses how to avoid plagiarism in a research paper. Avoiding plagiarism is part of a scientific writing ethic that always stated in any publication. Every writer should pay attention to their papers submitted to a journal or a scientific forum that they are free from unethical conduct. Writing a research paper needs overall accuracy especially in avoiding plagiarism in the paper that is to be published in a journal or to be presented at a certain scientific meeting, seminar or symposium. It is based on writers’ experience as a paper writer as well as a journal reviewer. The first application that the writers use is ‘checker’, a Mac computer application, used to check spelling and grammar. It assists the writers to check how misspelling and an ungrammatical inaccuracy in the writers’ papers. The second free application is ‘plagiarism checker’. Checking originality of a paper is essential and it is not too difficult to do today. It is freely accessible that plagiarism checker can be used to check how original the paper is. By visiting “Google” then write down ‘plagiarism checker’, it will appear ‘smallseatools’ and then the writers could choose and check how original the paper is. This application is freely accessed and helps immensely to check how original a paper is and how far a paper is free from plagiarism. The unoriginal phrase will be underlined and marked red and finally will be shown how inimitable the paper is. Plagiarism scan report which consists of the date of the report, plagiarism status, total words and total characters can be downloaded.

  10. Colostomy closure: how to avoid complications.

    Science.gov (United States)

    Bischoff, Andrea; Levitt, Marc A; Lawal, Taiwo A; Peña, Alberto

    2010-11-01

    Colostomy is an operation frequently performed in pediatric surgery. Despite its benefits, it can produce significant morbidity. In a previous publication we presented our experience with the errors and complications that occurred during cases of colostomy creation. We now have focused in the morbidity related to the colostomy closure. The technical details that might have contributed to the minimal morbidity we experienced are described. The medical records of 649 patients who underwent colostomy closure over a 28-year period were retrospectively reviewed looking for complications following these procedures. Our perioperative protocol for colostomy closure consisted in: clear fluids by mouth and repeated proximal stoma irrigations 24 h prior to the operation. Administration of IV antibiotics during anesthesia induction and continued for 48 h. Meticulous surgical technique that included: packing of the proximal stoma, plastic drape to immobilize the surgical field, careful hemostasis, emphasis in avoiding contamination, cleaning the edge of the stomas to allow a good 2-layer, end-to-end anastomosis with separated long-term absorbable sutures, generous irrigation of the peritoneal cavity and subsequent layers with saline solution, closure by layers to avoid dead space, and avoidance of hematomas. No drains and no nasogastric tubes were used. Oral fluids were started the day after surgery and patients were discharged 48-72 h after the operation. The original diagnoses of the patients were: anorectal malformation (583), Hirschsprung's disease (53), and others (13). 10 patients (1.5%) had complications: 6 had intestinal obstruction (5 due to small bowel adhesions, 1 had temporary delay of the function of the anastomosis due to a severe size discrepancy between proximal and distal stoma with a distal microcolon) and 4 incisional hernias. There were no anastomotic dehiscences or wound infection. There was no bleeding, no anastomotic stricture and no mortality. Based on

  11. Precision Landing and Hazard Avoidance Doman

    Science.gov (United States)

    Robertson, Edward A.; Carson, John M., III

    2016-01-01

    The Precision Landing and Hazard Avoidance (PL&HA) domain addresses the development, integration, testing, and spaceflight infusion of sensing, processing, and GN&C functions critical to the success and safety of future human and robotic exploration missions. PL&HA sensors also have applications to other mission events, such as rendezvous and docking. Autonomous PL&HA builds upon the core GN&C capabilities developed to enable soft, controlled landings on the Moon, Mars, and other solar system bodies. Through the addition of a Terrain Relative Navigation (TRN) function, precision landing within tens of meters of a map-based target is possible. The addition of a 3-D terrain mapping lidar sensor improves the probability of a safe landing via autonomous, real-time Hazard Detection and Avoidance (HDA). PL&HA significantly improves the probability of mission success and enhances access to sites of scientific interest located in challenging terrain. PL&HA can also utilize external navigation aids, such as navigation satellites and surface beacons. Advanced Lidar Sensors High precision ranging, velocimetry, and 3-D terrain mapping Terrain Relative Navigation (TRN) TRN compares onboard reconnaissance data with real-time terrain imaging data to update the S/C position estimate Hazard Detection and Avoidance (HDA) Generates a high-resolution, 3-D terrain map in real-time during the approach trajectory to identify safe landing targets Inertial Navigation During Terminal Descent High precision surface relative sensors enable accurate inertial navigation during terminal descent and a tightly controlled touchdown within meters of the selected safe landing target.

  12. The global cost of eliminating avoidable blindness

    Directory of Open Access Journals (Sweden)

    Kirsten L Armstrong

    2012-01-01

    Full Text Available Aims : To complete an initial estimate of the global cost of eliminating avoidable blindness, including the investment required to build ongoing primary and secondary health care systems, as well as to eliminate the ′backlog′ of avoidable blindness. This analysis also seeks to understand and articulate where key data limitations lie. Materials and Methods : Data were collected in line with a global estimation approach, including separate costing frameworks for the primary and secondary care sectors, and the treatment of backlog. Results : The global direct health cost to eliminate avoidable blindness over a 10-year period from 2011 to 2020 is estimated at $632 billion per year (2009 US$. As countries already spend $592 billion per annum on eye health, this represents additional investment of $397.8 billion over 10 years, which is $40 billion per year or $5.80 per person for each year between 2010 and 2020. This is concentrated in high-income nations, which require 68% of the investment but comprise 16% of the world′s inhabitants. For all other regions, the additional investment required is $127 billion. Conclusions : This costing estimate has identified that low- and middle-income countries require less than half the additional investment compared with high-income nations. Low- and middle-income countries comprise the greater investment proportion in secondary care whereas high-income countries require the majority of investment into the primary sector. However, there is a need to improve sector data. Investment in better data will have positive flow-on effects for the eye health sector.

  13. Avoiding object by robot using neural network

    International Nuclear Information System (INIS)

    Prasetijo, D.W.

    1997-01-01

    A Self controlling robot is necessary in the robot application in which operator control is difficult. Serial method such as process on the computer of van newman is difficult to be applied for self controlling robot. In this research, Neural network system for robotic control system was developed by performance expanding at the SCARA. In this research, it was shown that SCARA with application at Neural network system can avoid blocking objects without influence by number and density of the blocking objects, also departure and destination paint. robot developed by this study also can control its moving by self

  14. Common pitfalls to avoid during workover operations

    International Nuclear Information System (INIS)

    Byars, R.R.

    1994-01-01

    Remedial well work has been, and will continue to be, an integral part of oil company operations. More than 16,000 workover operations were performed during 1993 in the US. The economic impact from workover operations is usually immediate due to flowlines, tank batteries and other equipment being in place and ready for service prior to the workover. Similarly, problems encountered during workover operations contribute an immediate negative impact to project economics. Guidelines for common mistake avoidance are presented. They will be especially helpful for those individuals not well trained in workover preparation and supervision

  15. The International Double Taxation – Avoiding Methods

    Directory of Open Access Journals (Sweden)

    Nicoleta Barbuta-Misu

    2009-06-01

    Full Text Available The paper presents the main causes that determine double taxation, its forms, i.e. the economicdouble taxation and the international legal double taxation, the need for eliminating the double taxation andavoiding methods. In the presentation of the avoidance methods have been used practical examples forcomparison of the tax advantages for income beneficiary between: the total exemption method andprogressive exemption method, on the one hand, and total crediting method and ordinary crediting method,on the other hand, but the comparing of tax reduction between methods of exemption and crediting.

  16. CORPORATE SOCIAL RESPONSIBILITY VERSUS TAX AVOIDANCE PRACTICES

    Directory of Open Access Journals (Sweden)

    Stoian Ciprian-Dumitru

    2012-07-01

    Full Text Available Worldwide crisis has made multinational companies that are engaged in corporate social responsibility actions to manage their businesses through the lens of various tax avoidance practices. The content of this paper is important due to the fact that tries to identify the impact in case of companies active in corporate social responsibility actions versus their tax structures orientation. Corporate social responsibility literature did not paid enough attention on the impact of the tax avoidance practices of companies. Tax, as a concept, brings in itself an important corporate financial impact with subsequent effects for the life of multiple citizens in countries where private entities are operating. Even though companies are usually expressing their ethical and responsible conduct in respect of the social environment, there are many cases when the business practices were not aligned with the declared corporate behavior. This paper seeks firstly to examine whether companies engaged in tax avoidance practices (ex. offshore tax havens consider that continue to act socially responsible. Secondly, the paper examines the influence on attending the stakeholders’ goals for those companies practicing tax avoidance and its implications on corporate social responsibility actions. Moreover, the paper focuses also on the aspects described before from the perspective of the corporate entities operating in Romania. This paper’s intention is to use and to develop the results of previous research carried out by Lutz Preus (University of London and, subsequently, by Senators Levin, Coleman and Obama in their “Stop Tax Haven Abuse Bill”. The implications and the objectives of this material are to highlight, to identify and to spot clearly the relations and the influences of the tax haven practices of corporations versus their undertaken social responsibility actions. Moreover, this paper brings a fresh perspective of this topic from the

  17. Deterministic LOCA avoidance by gravity effect

    Energy Technology Data Exchange (ETDEWEB)

    Harms, A A [McMaster Univ., Hamilton, ON (Canada)

    1996-12-31

    A novel concept for an intrinsically safe reactor, called the Pellet Suspension Reactor (PSR), has vertical fuel tubes in which fuel, in the form of micro-pellets, is suspended by an upwardly flowing liquid or (preferably) gas coolant. Then, in the event of a primary pump failure, the fuel pellets fall down into a divergent conical annulus which is surrounded by ordinary water; the divergent geometry of this catchment ensures nuclear subcriticality, and the annulus will ensure decay-heat removal by packed-bed conduction. Thus melting of the fuel is avoided, and no emergency shut-down or emergency cooling provisions are required. 7 refs., 1 tab., 1 fig.

  18. Collision Avoidance for Airport Traffic Concept Evaluation

    Science.gov (United States)

    Jones, Denise R.; Prinzel, Lawrence J., III; Otero, Sharon D.; Barker, Glover D.

    2009-01-01

    An initial Collision Avoidance for Airport Traffic (CAAT) concept for the Terminal Maneuvering Area (TMA) was evaluated in a simulation study at the National Aeronautics and Space Administration (NASA) Langley Research Center. CAAT is being designed to enhance surface situation awareness and provide cockpit alerts of potential conflicts during runway, taxi, and low altitude air-to-air operations. The purpose of the study was to evaluate the initial concept for an aircraft-based method of conflict detection and resolution (CD&R) in the TMA focusing on conflict detection algorithms and alerting display concepts. This paper gives an overview of the CD&R concept, simulation study, and test results.

  19. Guide to the collision avoidance rules

    CERN Document Server

    Cockcroft, A N

    2004-01-01

    A Guide to the Collision Avoidance Rules is the essential reference to the safe operation of all vessels at sea. Published continuously since 1965, this respected and expert guide is the classic text for all who need to, practically and legally, understand and comply with the Rules. This sixth edition incorporates all of the amendments to the International Regulations for Preventing Collisions at Sea which came into force in November 2003.The books sets out all of the Rules with clear explanation of their meaning, and gives detailed examples of how the rules have been used in practice

  20. Avoiding plagiarism: guidance for nursing students.

    Science.gov (United States)

    Price, Bob

    The pressures of study, diversity of source materials, past assumptions relating to good writing practice, ambiguous writing guidance on best practice and students' insecurity about their reasoning ability, can lead to plagiarism. With the use of source checking software, there is an increased chance that plagiarised work will be identified and investigated, and penalties given. In extreme cases, plagiarised work may be reported to the Nursing and Midwifery Council and professional as well as academic penalties may apply. This article provides information on how students can avoid plagiarism when preparing their coursework for submission.

  1. Wireless vehicular networks for car collision avoidance

    CERN Document Server

    2013-01-01

    Wireless Vehicular Networks for Car Collision Avoidance focuses on the development of the ITS (Intelligent Transportation Systems) in order to minimize vehicular accidents. The book presents and analyses a range of concrete accident scenarios while examining the causes of vehicular collision and proposing countermeasures based on wireless vehicular networks. The book also describes the vehicular network standards and quality of service mechanisms focusing on improving critical dissemination of safety information. With recommendations on techniques and protocols to consider when improving road safety policies in order to minimize crashes and collision risks.

  2. Vigilance-avoidance and disengagement are differentially associated with fear and avoidant behaviors in social anxiety.

    Science.gov (United States)

    Evans, Travis C; Walukevich, Katherine A; Britton, Jennifer C

    2016-07-15

    Individuals with Social Anxiety Disorder (SAD) often exhibit preferential attention for social threat, demonstrating abnormal orientation to threat (i.e., vigilance-avoidance) and/or difficulty disengaging from threat. However, no research has compared the relationship between attention indices (i.e., vigilance-avoidance, difficulty disengaging from threat) and characteristic features of the disorder such as fear during social situations (social fear) and avoidant behaviors (social avoidance). To address this issue, seventy adults (19.29±1.47 years, 33 females) were separated into low (n=37) or high (n=33) socially anxious groups using clinical cutoff scores on the Social Interaction Anxiety Scale (SIAS). Participants in both groups completed a dot-probe task with congruent, incongruent, and neutral trials to obtain measures of vigilance-avoidance and difficulty disengaging. Using linear regression, we examined the associations each attention index shared with self-reported social fear and social avoidance. Exclusively in the high anxious group, greater vigilance towards threat was associated with higher self-reported social fear, but not with social avoidance. However, difficulty disengaging was not associated with either social measure. In the low anxiety group, no relationships between attention indices and either social measure emerged. Future research with clinical samples is necessary to replicate and extend these findings. The small sample size studied may have limited our ability to detect other smaller effects. Indices of attention bias may contribute differently to the etiology and maintenance of SAD, which offers important implications for novel treatments that target attention. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Avoiding humiliations in the clinical encounter.

    Science.gov (United States)

    Malterud, Kirsti; Hollnagel, Hanne

    2007-06-01

    To explore potentials for avoiding humiliations in clinical encounters, especially those that are unintended and unrecognized by the doctor. Furthermore, to examine theoretical foundations of degrading behaviour and identify some concepts that can be used to understand such behaviour in the cultural context of medicine. Finally, these concepts are used to build a model for the clinician in order to prevent humiliation of the patient. Empirical studies document experiences of humiliation among patients when they see their doctor. Philosophical and sociological analysis can be used to explain the dynamics of unintended degrading behaviour between human beings. Skjervheim, Vetlesen, and Bauman have identified the role of objectivism, distantiation, and indifference in the dynamics of evil acts, pointing to the rules of the cultural system, rather than accusing the individual of bad behaviour. Examining the professional role of the doctor, parallel traits embedded in the medical culture are demonstrated. According to Vetlesen, emotional awareness is necessary for moral perception, which again is necessary for moral performance. A better balance between emotions and rationality is needed to avoid humiliations in the clinical encounter. The Awareness Model is presented as a strategy for clinical practice and education, emphasizing the role of the doctor's own emotions. Potentials and pitfalls are discussed.

  4. Shape optimization of self-avoiding curves

    Science.gov (United States)

    Walker, Shawn W.

    2016-04-01

    This paper presents a softened notion of proximity (or self-avoidance) for curves. We then derive a sensitivity result, based on shape differential calculus, for the proximity. This is combined with a gradient-based optimization approach to compute three-dimensional, parameterized curves that minimize the sum of an elastic (bending) energy and a proximity energy that maintains self-avoidance by a penalization technique. Minimizers are computed by a sequential-quadratic-programming (SQP) method where the bending energy and proximity energy are approximated by a finite element method. We then apply this method to two problems. First, we simulate adsorbed polymer strands that are constrained to be bound to a surface and be (locally) inextensible. This is a basic model of semi-flexible polymers adsorbed onto a surface (a current topic in material science). Several examples of minimizing curve shapes on a variety of surfaces are shown. An advantage of the method is that it can be much faster than using molecular dynamics for simulating polymer strands on surfaces. Second, we apply our proximity penalization to the computation of ideal knots. We present a heuristic scheme, utilizing the SQP method above, for minimizing rope-length and apply it in the case of the trefoil knot. Applications of this method could be for generating good initial guesses to a more accurate (but expensive) knot-tightening algorithm.

  5. Avoided operating costs in thermal generating systems

    International Nuclear Information System (INIS)

    Chowdhury, N.; Billinton, R.; Gupta, R.

    1995-01-01

    A simple and straightforward technique was developed to assess avoided system operating costs associated with non-utility generation (NUG). The technique was based on optimum loading configurations of the committed units both before and after the inclusion of NUG energy. The salient features of the technique were presented in this paper. Assessment of avoided operating cost with deterministic and probabilistic criteria were explained. A time differentiated price system was adopted in the algorithms to reflect the different value placed on purchased price by a utility at different times of the day. The algorithms show the utility effects of dispatchable and non-dispatchable NUG energies. The IEEE Reliability Test System (RTS) was utilized for numerical analysis. Results were illustrated. It was found that sensitivity studies similar to those performed on the IEEE-RTS could be utilized to determine the amount of energy and the time period during which utilities and NUGs can maximize their economic benefits. 7 refs., 5 figs., 1 tab

  6. Colostomy closure: how to avoid complications

    Science.gov (United States)

    Levitt, Marc A.; Lawal, Taiwo A.; Peña, Alberto

    2010-01-01

    Purpose Colostomy is an operation frequently performed in pediatric surgery. Despite its benefits, it can produce significant morbidity. In a previous publication we presented our experience with the errors and complications that occurred during cases of colostomy creation. We now have focused in the morbidity related to the colostomy closure. The technical details that might have contributed to the minimal morbidity we experienced are described. Methods The medical records of 649 patients who underwent colostomy closure over a 28-year period were retrospectively reviewed looking for complications following these procedures. Our perioperative protocol for colostomy closure consisted in: clear fluids by mouth and repeated proximal stoma irrigations 24 h prior to the operation. Administration of IV antibiotics during anesthesia induction and continued for 48 h. Meticulous surgical technique that included: packing of the proximal stoma, plastic drape to immobilize the surgical field, careful hemostasis, emphasis in avoiding contamination, cleaning the edge of the stomas to allow a good 2-layer, end-to-end anastomosis with separated long-term absorbable sutures, generous irrigation of the peritoneal cavity and subsequent layers with saline solution, closure by layers to avoid dead space, and avoidance of hematomas. No drains and no nasogastric tubes were used. Oral fluids were started the day after surgery and patients were discharged 48–72 h after the operation. Results The original diagnoses of the patients were: anorectal malformation (583), Hirschsprung’s disease (53), and others (13). 10 patients (1.5%) had complications: 6 had intestinal obstruction (5 due to small bowel adhesions, 1 had temporary delay of the function of the anastomosis due to a severe size discrepancy between proximal and distal stoma with a distal microcolon) and 4 incisional hernias. There were no anastomotic dehiscences or wound infection. There was no bleeding, no anastomotic

  7. Avoidant/Restrictive Food Intake Disorder (ARFID).

    Science.gov (United States)

    Zimmerman, Jacqueline; Fisher, Martin

    2017-04-01

    Avoidant/restrictive food intake disorder (ARFID) is an entirely new diagnosis in the DSM-5. ARFID replaces "feeding disorder of infancy or early childhood," which was a diagnosis in the DSM-IV restricted to children 6 years of age or younger; ARFID has no such age limitations and it is distinct from anorexia nervosa and bulimia nervosa in that there is no body image disturbance. ARFID involves a complex and heterogenous etiology, which is reviewed herein. What is known to date regarding the characteristics and medical and psychiatric comorbidities of this patient population are described and compared to other eating disorders. Evaluation and management strategies are also discussed. No data yet exist regarding ARFID׳s prognosis and prevention; however, recommendations to guide parents in establishing appropriate infant and child feeding practices are provided. Copyright © 2017 Mosby, Inc. All rights reserved.

  8. Avoiding Deontic Explosion by Contextually Restricting Aggregation

    Science.gov (United States)

    Meheus, Joke; Beirlaen, Mathieu; van de Putte, Frederik

    In this paper, we present an adaptive logic for deontic conflicts, called P2.1 r , that is based on Goble's logic SDL a P e - a bimodal extension of Goble's logic P that invalidates aggregation for all prima facie obligations. The logic P2.1 r has several advantages with respect to SDL a P e. For consistent sets of obligations it yields the same results as Standard Deontic Logic and for inconsistent sets of obligations, it validates aggregation "as much as possible". It thus leads to a richer consequence set than SDL a P e. The logic P2.1 r avoids Goble's criticisms against other non-adjunctive systems of deontic logic. Moreover, it can handle all the 'toy examples' from the literature as well as more complex ones.

  9. Avoidable deaths in Greenland 1968-1985

    DEFF Research Database (Denmark)

    Bjerregaard, Peter; Juel, K

    1990-01-01

    and several showed an increasing time trend. The regional patterns were particularly clear for infectious diseases and accidents, which showed low mortality rates in the capital and other towns and high mortality rates in settlements and in the remote East Greenland, while mortality rates from suicides...... and political will of the society. A list of avoidable deaths is proposed for Greenland which includes, inter alia, meningitis, lung cancer, acute respiratory infections, suicides, boat accidents and alcohol related diseases and accidents. All were considerably more common in Greenland than in Denmark...... and alcohol related diseases were high in the capital and East Greenland and low in West Greenlandic settlements. It is concluded that further studies on preventable diseases and causes of death, in particular certain infectious diseases, accidents and suicides, are needed....

  10. Discovering and avoiding self-contradiction:

    DEFF Research Database (Denmark)

    Olivares Bøgeskov, Benjamin Miguel

    aspects –first developing critical self-refection and secondly developing skills to conduct an ethical dialogue. The first aspect is addressed by finding out what the students think, do they contradict themselves and how to avoid self-contradictions. This is done by using a questionnaire with 13 ethical...... the theory and see the consequences of such theories in concrete cases, but would not use any of these theories to justify their own ethical decisions in other contexts. In other words, courses were failing to provide the students with theoretical tools that they could apply outside the classroom. Therefore......, this method focuses not so much on teaching what other people think, but rather starts by finding out what the students think, and to which degree they contradict themselves. In addition the method focuses on how students argue for their positions when entering an ethical dialogue. The method focuses on two...

  11. Mars rover local navigation and hazard avoidance

    Science.gov (United States)

    Wilcox, B. H.; Gennery, D. B.; Mishkin, A. H.

    1989-01-01

    A Mars rover sample return mission has been proposed for the late 1990's. Due to the long speed-of-light delays between earth and Mars, some autonomy on the rover is highly desirable. JPL has been conducting research in two possible modes of rover operation, Computer-Aided Remote Driving and Semiautonomous Navigation. A recently-completed research program used a half-scale testbed vehicle to explore several of the concepts in semiautonomous navigation. A new, full-scale vehicle with all computational and power resources on-board will be used in the coming year to demonstrate relatively fast semiautonomous navigation. The computational and power requirements for Mars rover local navigation and hazard avoidance are discussed.

  12. Integrated disruption avoidance and mitigation in KSTAR

    International Nuclear Information System (INIS)

    Kim, Jayhyun; Woo, M.H.; Han, H.; In, Y.; Bak, J.G.; Eidietis, N.W.

    2014-01-01

    The final target of Korea Superconducting Tokamak Advanced Research (KSTAR) aims advanced tokamak operation at plasma current 2 MA and toroidal field 3.5 T. In order to safely achieve the target, disruption counter-measures are unavoidable when considering the disruption risks, inevitably accompanied with high performance discharges, such as electro-magnetic load on conducting structures, collisional damage by run-away electrons, and thermal load on plasma facing components (PFCs). In this reason, the establishment of integrated disruption mitigation system (DMS) has been started for routine mega-ampere class operations of KSTAR since 2013 campaign. The DMS mainly consists of the disruption prediction and its avoidance/mitigation in company with logical/technical integration of them. We present the details of KSTAR DMS and the related experimental results in this article. (author)

  13. Avoiding sexual harassment liability in veterinary practices.

    Science.gov (United States)

    Lacroix, C A; Wilson, J F

    1996-05-15

    Harassment based on gender violates the rule of workplace equality established by Title VII of the Civil Rights Act and enforced by the EEOC. In 1986, the US Supreme Court, in Meritor Savings Bank v Vinson, established the criteria that must be met for a claim of hostile environment sexual harassment to be considered valid. Plaintiffs must show that they were subjected to conduct based on their gender, that it was unwelcome, and that it was severe and pervasive enough to alter their condition of employment, resulting in an abusive working environment. There have been few sexual harassment cases involving veterinary professionals, and it is our goal to help keep the number of filed actions to a minimum. The most effective way to avoid hostile environment sexual harassment claims is to confront the issue openly and to adopt a sexual harassment policy for the practice. When it comes to sexual harassment, an ounce of prevention is unquestionably worth a pound of cure.

  14. Life stressors, emotional avoidance and breast cancer.

    Science.gov (United States)

    Cardenal, Violeta; Ortiz-Tallo, Margarita; Martín Frías, Isabel; Martínez Lozano, Joaquina

    2008-11-01

    Two groups of women were assessed in psychological aspects considered by some authors of interest for personal well-being. The sample consisted of 118 women, 58 diagnosed with breast cancer and 60 healthy women, of similar ages and personal circumstances. The purpose of the study was: (a) to explore the existence of stressful life events in the women's history and their degree of subjective distress and (b) to determine whether or not there is an emotional avoidance style in the group of women with breast cancer. The following assessment instruments were employed: the "Cuestionario de Formas de Afrontamiento" (CEA), the Five-Factor Inventory NEO-PI-R, and the State-Trait Anger Inventory (STAXI). The results revealed more stressful vital events in the last two years in the group of women with breast cancer and significant differences in the degree of current distress. They also obtained higher scores in current anger, resignation, and neuroticism.

  15. Tax Anti-avoidance Through Transfer Pricing

    DEFF Research Database (Denmark)

    Rossing, Christian Plesner; Riise Johansen, Thomas; Pearson, Thomas C.

    2016-01-01

    -driven discipline to be dealt with by accounting and tax experts. Instead, MNEs face the task of establishing a complex fit with their environment beyond the typical stakeholders with transfer pricing, i.e. tax authorities. These include government officials, tax activists, and consumers who voice......This paper examines the case of Starbucks’ UK branch, which became subject to massive public criticism over alleged tax avoidance. Despite Starbucks arguing that its transfer pricing practices were in full compliance with regulatory requirements, public pressure for higher corporate tax payments...... led Starbucks to increase its UK tax payment on transfer pricing income beyond regulatory requirements. This case study suggests that MNE tax behavior on international transfer pricing is not strictly a matter of compliance with formal tax regulation. We demonstrate the way an MNE attempts to re...

  16. Experiential Avoidance and Technological Addictions in Adolescents.

    Science.gov (United States)

    García-Oliva, Carlos; Piqueras, José A

    2016-06-01

    Background and aims This study focuses on the use of popular information and communication technologies (ICTs) by adolescents: the Internet, mobile phones, and video games. The relationship of ICT use and experiential avoidance (EA), a construct that has emerged as underlying and transdiagnostic to a wide variety of psychological problems, including behavioral addictions, is examined. EA refers to a self-regulatory strategy involving efforts to control or escape from negative stimuli such as thoughts, feelings, or sensations that generate strong distress. This strategy, which may be adaptive in the short term, is problematic if it becomes an inflexible pattern. Thus, the aim of this study was to explore whether EA patterns were associated with addictive or problematic use of ICT in adolescents. Methods A total of 317 students of the Spanish southeast between 12 and 18 years old were recruited to complete a questionnaire that included questions about general use of each ICTs, an experiential avoidance questionnaire, a brief inventory of the Big Five personality traits, and specific questionnaires on problematic use of the Internet, mobile phones, and video games. Results Correlation analysis and linear regression showed that EA largely explained results regarding the addictive use of the Internet, mobile phones, and video games, but not in the same way. As regards gender, boys showed a more problematic use of video games than girls. Concerning personality factors, conscientiousness was related to all addictive behaviors. Discussion and conclusions We conclude that EA is an important construct that should be considered in future models that attempt to explain addictive behaviors.

  17. Experiential Avoidance and Technological Addictions in Adolescents

    Science.gov (United States)

    García-Oliva, Carlos; Piqueras, José A.

    2016-01-01

    Background and aims This study focuses on the use of popular information and communication technologies (ICTs) by adolescents: the Internet, mobile phones, and video games. The relationship of ICT use and experiential avoidance (EA), a construct that has emerged as underlying and transdiagnostic to a wide variety of psychological problems, including behavioral addictions, is examined. EA refers to a self-regulatory strategy involving efforts to control or escape from negative stimuli such as thoughts, feelings, or sensations that generate strong distress. This strategy, which may be adaptive in the short term, is problematic if it becomes an inflexible pattern. Thus, the aim of this study was to explore whether EA patterns were associated with addictive or problematic use of ICT in adolescents. Methods A total of 317 students of the Spanish southeast between 12 and 18 years old were recruited to complete a questionnaire that included questions about general use of each ICTs, an experiential avoidance questionnaire, a brief inventory of the Big Five personality traits, and specific questionnaires on problematic use of the Internet, mobile phones, and video games. Results Correlation analysis and linear regression showed that EA largely explained results regarding the addictive use of the Internet, mobile phones, and video games, but not in the same way. As regards gender, boys showed a more problematic use of video games than girls. Concerning personality factors, conscientiousness was related to all addictive behaviors. Discussion and conclusions We conclude that EA is an important construct that should be considered in future models that attempt to explain addictive behaviors. PMID:27363463

  18. Main and combined effects of musculoskeletal pain frequency and avoidant coping on sickness absence

    DEFF Research Database (Denmark)

    Christensen, Ulla; Schmidt, Lone; Hougaard, Charlotte Orsted

    2013-01-01

    Objective: Musculoskeletal pain and avoidant coping predicts sickness absence, but how these 2 predictors relate to each other is unknown. We examined the main and combined effects of musculoskeletal pain and avoidant, behavioural coping on incidence of sickness absence. Design and subjects......: Prospective cohort study of a sample of middle-aged Danes, economically active in 2006, reporting functional limitations due to musculoskeletal pain, n = 3115. Methods: Data included surveys from 2000 and 2006 and register data from 2007. Outcome was sickness absence exceeding 2 consecutive weeks in 2007....... The main effect of self-reported pain frequency and avoidant coping on sickness absence was analysed by multivariate logistic regression. The combined effect was calculated as departure from multiplicativity and by the inclusion of a product term. Results: Daily pain and use of avoidant coping were both...

  19. Technology for recovery of by-products

    International Nuclear Information System (INIS)

    Van Tuy, H.H.

    1983-01-01

    Products of conventional nuclear fuel processing plants are uranium and plutonium, and any other recovered material is considered to be a by-product. Some by-products have been recovered from past nuclear fuel processing operations, either as a normal mode of operation or by special campaigns. Routing recovery over an extended period has been limited to neptunium, but extended campaigns were used at Hanford to recover strontium for radioisotope thermoelectric generators. Krypton is recovered at Idaho Chemical Processing Plant on a campaign basis, and isotope separation of krypton is done at Oak Ridge National Laboratory. Past campaigns at Hanford PUREX have recovered cesium, promethium, amercium, cerium, and technetium. Past by-product recovery efforts were usually severely constrained by the status of flowsheet development and availability of existing facilities at the time decisions wee made to recover the by-products. Additional processes were developed to accommodate other unit operations and in response to changes in waste management objectives or user requirements. Now an impressive variety of recovery technology is available for most potential by-products, with varying degrees of demonstration under conditions which satisfy today's environmental protection and waste management constraints

  20. Avoidance orientation moderates the effect of threatening messages

    NARCIS (Netherlands)

    Riet, van 't J.P.; Ruiter, R.A.C.; Vries, de H.

    2012-01-01

    This study investigated the influence of individual differences in people's dispositional avoidance orientation on the persuasive effects of low- and high-threat messages promoting moderate drinking. First, participents (N = 99) individual differences in avoidance orientation were assessed, after

  1. Litigation-proof patents: avoiding the most common patent mistakes

    National Research Council Canada - National Science Library

    Goldstein, Larry M

    2014-01-01

    "Litigation-Proof Patents: Avoiding the Most Common Patent Mistakes explains the principles of excellent patents, presents the ten most common errors in patents, and details a step-by-step method for avoiding these common errors...

  2. Auditory distraction and serial memory: The avoidable and the ineluctable

    Directory of Open Access Journals (Sweden)

    Dylan M Jones

    2010-01-01

    Full Text Available One mental activity that is very vulnerable to auditory distraction is serial recall. This review of the contemporary findings relating to serial recall charts the key determinants of distraction. It is evident that there is one form of distraction that is a joint product of the cognitive characteristics of the task and of the obligatory cognitive processing of the sound. For sequences of sound, distraction appears to be an ineluctable product of similarity-of-process, specifically, the serial order processing of the visually presented items and the serial order coding that is the by-product of the streaming of the sound. However, recently emerging work shows that the distraction from a single sound (one deviating from a prevailing sequence results in attentional capture and is qualitatively distinct from that of a sequence in being restricted in its action to encoding, not to rehearsal of list members. Capture is also sensitive to the sensory task load, suggesting that it is subject to top-down control and therefore avoidable. These two forms of distraction-conflict of process and attentional capture-may be two consequences of auditory perceptual organization processes that serve to strike the optimal balance between attentional selectivity and distractability.

  3. Relative valuation of alternative methods of tax avoidance

    OpenAIRE

    Inger, Kerry Katharine

    2012-01-01

    This paper examines the relative valuation of alternative methods of tax avoidance. Prior studies find that firm value is positively associated with overall measures of tax avoidance; I extend this research by providing evidence that investors distinguish between methods of tax reduction in their valuation of tax avoidance. The impact of tax avoidance on firm value is a function of tax risk, permanence of tax savings, tax planning costs, implicit taxes and contrasts in disclosures of tax re...

  4. Communication Avoiding and Overlapping for Numerical Linear Algebra

    Science.gov (United States)

    2012-05-08

    future exascale systems, communication cost must be avoided or overlapped. Communication-avoiding 2.5D algorithms improve scalability by reducing...linear algebra problems to future exascale systems, communication cost must be avoided or overlapped. Communication-avoiding 2.5D algorithms improve...will continue to grow relative to the cost of computation. With exascale computing as the long-term goal, the community needs to develop techniques

  5. CEO Power, Corporate Tax Avoidance and Tax Aggressiveness

    OpenAIRE

    GATOT SOEPRIYANTO

    2017-01-01

    My thesis investigates the association between CEO power, corporate tax avoidance and tax aggressiveness, using two organizational theory perspectives: self-interest and stewardship. I find that a powerful CEO engages in less corporate tax avoidance activities, which lends credence to the risk minimization motive of the stewardship perspective. My findings on the association between CEO power and tax aggressiveness show that powerful CEOs avoid risky tax avoidance strategies that expose a fir...

  6. Landslide disaster avoidance: learning from Leyte

    Science.gov (United States)

    Davies, T. R.

    2006-12-01

    On 17 February 2006 a gigantic rockslide triggered a debris avalanche that overran the barangay Guinsaugon, St. Bernard in Southern Leyte Province, Philippines, burying 154 victims, with 990 missing including 246 school children. Even with satellite imagery, GIS-based landslide susceptibility modelling and real-time meteorological and seismic data analysis, scientific prediction of every potentially fatal landslide is not possible in most parts of the world. This is particular the case in steep, unstable, densely-populated country in which heavy rain is common. So how can further events of this type be prevented from turning into disasters? A number of precursory phenomena were noted by local inhabitants at Guinsaugon: a crack around the slope that failed was noticed in May 2005; coconut trees near the northern foot of the landslide scarp began to lean increasingly in the down-slope direction in December 2005; a slope around the northern edge of the 17 February 2006 landslide scarp failed on December 17, 2005; in the 9 days prior to the rockslide, 640 mm of rain fell; 450 mm in a 3-day period. Such phenomena are commonly reported by local inhabitants before large landslides (e.g. Elm, Mayunmarca, and many others). In many cases, therefore, it is in principle possible for local people to avoid the consequences of the landslide if they know enough to act appropriately in response to the precursory phenomena. For this possibility to be realized, appropriate information must be provided to and assimilated by the local population. Useful ways of achieving this include pamphlets, video, TV and radio programs and visits from civil defence personnel. The information must be properly presented; scientific language will be ineffective. A communication pyramid, leading from government agencies to local leaders, can facilitate the rapid availability of the information to all potentially susceptible communities. If science can determine those areas not vulnerable to landslide

  7. Avoiding surety contracts in bankruptcy procedure

    Directory of Open Access Journals (Sweden)

    Hiber Dragor

    2015-01-01

    Full Text Available Serbia's courts jurisprudence has divergent attitudes with respect to the dilemma whether a surety contract represents a contract without consideration, which may be avoided once the guarantor is subject to bankruptcy procedure without any additional conditions, or an onerous contract. Whether a surety contract is an onerous one has anyhow been disputed in the legal theory. One school of thought considers this contract as non-onerous one, since vis-a-vis guarantor's obligation no benefit to be expected from the other contractual party (i. e. creditor exists. The other school of thought understands surety (almost always as an onerous contract bearing in mind that the guarantor who enters into this contract does not have intentio liberalis. There are numerous and nuanced views based on analyses of the relation between a guarantor and a debtor focused on the argument that surety is a contract without consideration if intentio liberalis existed vis-a-vis main debtor rather than vis-a-vis creditor. Our legal literature did not pay much attention to that issue until recently. In a rare text dedicated to it the author's basic standpoint is that surety represents a contract without consideration. An exception, depending on the circumstances of the case, could be surety given by a parent company for the obligation of a subsidiary, provided the former reasonably expected a benefit in terms of an increase in the value of shares. Commercial courts followed such reasoning. In this article an opposite stance has been argued. Namely, the onerousness of surety must be assessed based on the relation between the guarantor and the main debtor rather than between the guarantor and the creditor. As a rule, surety is an onerous contract because the guarantor expects to collect from the debtor through subrogation the amount he paid to the creditor; exceptionally, surety may be a non-onerous contract if intentio liberalis existed vis-a-vis main debtor. However, this

  8. Avoidance and tolerance to avian herbivores in aquatic plants

    NARCIS (Netherlands)

    Hidding, A.

    2009-01-01

    Tolerance and avoidance are the two contrasting strategies that plants may adopt to cope with herbivores. Tolerance traits define the degree to which communities remain unaffected by herbivory. Trade-offs between herbivore avoidance and competitive strength and between avoidance and colonization

  9. Brief cognitive therapy for avoidant personality disorder.

    Science.gov (United States)

    Rees, Clare S; Pritchard, Rhian

    2015-03-01

    Avoidant personality disorder (APD) is associated with a high level of impairment in multiple areas of functioning. However, research on the treatment of APD is scarce, and there is an absence of empirically evaluated effective treatment approaches available. This study offers a preliminary investigation of the use of brief cognitive therapy to treat APD. Two individuals, both with a principal diagnosis of APD, but who also possessed a number of comorbidities, participated in 12 weekly sessions. A series of diagnostic symptom severity, global functioning, and self-report measures were completed at pretreatment, posttreatment and at 6-week follow-up. In addition, regular monitoring of each participant's strength of belief in 4 personally identified cognitions associated with APD was completed. Reductions in APD symptoms, associated negative affect, and increases to quality of life were observed for both participants at posttreatment and follow-up phases. Results suggest that brief cognitive therapy may be an effective treatment for APD and that further studies with larger samples are warranted. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

  10. Spaced taste avoidance conditioning in Lymnaea.

    Science.gov (United States)

    Takigami, Satoshi; Sunada, Hiroshi; Lukowiak, Ken; Sakakibara, Manabu

    2014-01-01

    We succeeded in taste avoidance conditioning with sucrose as the conditional stimulus (CS) and an electrical stimulus (∼1000V, 80μA) as the unconditional stimulus (US). With 15 paired CS-US presentations on a single day, we were able to elicit both short-term memory (STM) and long-term memory (LTM) persisting for at least one week. However, while STM was elicited with 5, 8, 10, and 20 paired presentations of the CS-US on a single day, LTM was not. We found, however, that if we inserted a 3h interval between a first and a second set of CS-US pairings that both 8 and 20 paired CS-US presentations on a single day was now sufficient to cause LTM formation. Exposing snails to bryostatin before or during training enhanced LTM formation such that 8 paired presentations of the CS-US resulted in LTM. Copyright © 2013 Elsevier Inc. All rights reserved.

  11. The amygdala: securing pleasure and avoiding pain

    Directory of Open Access Journals (Sweden)

    Anushka B P Fernando

    2013-12-01

    Full Text Available The amygdala has traditionally been associated with fear, mediating the impact of negative emotions on memory. However, this view does not fully encapsulate the function of the amygdala, nor the impact that processing in this structure has on the motivational limbic corticostriatal circuitry of which it is an important structure. Here we discuss the interactions between different amygdala nuclei with cortical and striatal regions involved in motivation; interconnections and parallel circuitries that have become increasingly understood in recent years. We review the evidence that the amygdala stores memories that allow initially motivationally neutral stimuli to become associated through pavlovian conditioning with motivationally relevant outcomes which, importantly, can be either appetitive (e.g. food or aversive (e.g. electric shock. We also consider how different psychological processes supported by the amygdala such as conditioned reinforcement and punishment, conditioned motivation and suppression, and conditioned approach and avoidance behavior, are not only psychologically but also neurobiologically dissociable, being mediated by distinct yet overlapping neural circuits within the limbic corticostriatal circuitry. Clearly the role of the amygdala goes beyond encoding aversive stimuli to also encode the appetitive, requiring an appreciation of the amygdala’s mediation of both appetitive and fearful behavior through diverse psychological processes.

  12. Cooperative organic mine avoidance path planning

    Science.gov (United States)

    McCubbin, Christopher B.; Piatko, Christine D.; Peterson, Adam V.; Donnald, Creighton R.; Cohen, David

    2005-06-01

    The JHU/APL Path Planning team has developed path planning techniques to look for paths that balance the utility and risk associated with different routes through a minefield. Extending on previous years' efforts, we investigated real-world Naval mine avoidance requirements and developed a tactical decision aid (TDA) that satisfies those requirements. APL has developed new mine path planning techniques using graph based and genetic algorithms which quickly produce near-minimum risk paths for complicated fitness functions incorporating risk, path length, ship kinematics, and naval doctrine. The TDA user interface, a Java Swing application that obtains data via Corba interfaces to path planning databases, allows the operator to explore a fusion of historic and in situ mine field data, control the path planner, and display the planning results. To provide a context for the minefield data, the user interface also renders data from the Digital Nautical Chart database, a database created by the National Geospatial-Intelligence Agency containing charts of the world's ports and coastal regions. This TDA has been developed in conjunction with the COMID (Cooperative Organic Mine Defense) system. This paper presents a description of the algorithms, architecture, and application produced.

  13. Avoidable cancers in the Nordic countries. Occupation

    DEFF Research Database (Denmark)

    Dreyer, L; Andersen, A; Pukkala, E

    1997-01-01

    million people (3.7 million men and 0.2 million women) in the Nordic countries were potentially exposed to above-average levels of one or more verified industrial carcinogens. It is expected that these exposures will result in a total of about 1,900 new cases of cancer every year in the Nordic countries...... around the year 2000, with 1,890 among men and fewer than 25 among women. The proportions that could be avoided if industrial carcinogens were eliminated would be 70% of mesotheliomas, 20% of cancers of the nasal cavity and sinuses, 12% of lung cancers, 5% of laryngeal cancers, 2% of urinary bladder...... cancers, 1% of the leukaemias, and 1% of renal cancers. Overall, it is estimated that verified industrial carcinogens will account for approximately 3% of all cancers in men and less than 0.1% of all cancers in women in the Nordic countries around the year 2000. No attempt was made to estimate...

  14. Collision detection and avoidance during treatment planning

    International Nuclear Information System (INIS)

    Humm, John L.; Pizzuto, Domenico; Fleischman, Eric; Mohan, Radhe

    1995-01-01

    Purpose: To develop computer software that assists the planner avoid potential gantry collisions with the patient or patient support assembly during the treatment planning process. Methods and Materials: The approach uses a simulation of the therapy room with a scale model of the treatment machine. Because the dimensions of the machine and patient are known, one can calculate a priori whether any desired therapy field is possible or will result in a collision. To assist the planner, we have developed a graphical interface enabling the accurate visualization of each treatment field configuration with a 'room's eye view' treatment planning window. This enables the planner to be aware of, and alleviate any potential collision hazards. To circumvent blind spots in the graphic representation, an analytical software module precomputes whether each update of the gantry or turntable position is safe. Results: If a collision is detected, the module alerts the planner and suggests collision evasive actions such as either an extended distance treatment or the gantry angle of closest approach. Conclusions: The model enables the planner to experiment with unconventional noncoplanar treatment fields, and immediately test their feasibility

  15. Aerial vehicles collision avoidance using monocular vision

    Science.gov (United States)

    Balashov, Oleg; Muraviev, Vadim; Strotov, Valery

    2016-10-01

    In this paper image-based collision avoidance algorithm that provides detection of nearby aircraft and distance estimation is presented. The approach requires a vision system with a single moving camera and additional information about carrier's speed and orientation from onboard sensors. The main idea is to create a multi-step approach based on a preliminary detection, regions of interest (ROI) selection, contour segmentation, object matching and localization. The proposed algorithm is able to detect small targets but unlike many other approaches is designed to work with large-scale objects as well. To localize aerial vehicle position the system of equations relating object coordinates in space and observed image is solved. The system solution gives the current position and speed of the detected object in space. Using this information distance and time to collision can be estimated. Experimental research on real video sequences and modeled data is performed. Video database contained different types of aerial vehicles: aircrafts, helicopters, and UAVs. The presented algorithm is able to detect aerial vehicles from several kilometers under regular daylight conditions.

  16. Approach-avoidance activation without anterior asymmetry

    Directory of Open Access Journals (Sweden)

    Andero eUusberg

    2014-03-01

    Full Text Available Occasionally, the expected effects of approach-avoidance motivation on anterior EEG alpha asymmetry fail to emerge, particularly in studies using affective picture stimuli. These null findings have been explained by insufficient motivational intensity of, and/or overshadowing interindividual variability within the responses to emotional pictures. These explanations were systematically tested using data from 70 students watching 5 types of affective pictures ranging from very pleasant to unpleasant. The stimulus categories reliably modulated self-reports as well as the amplitude of late positive potential, an ERP component reflecting orienting towards motivationally significant stimuli. The stimuli did not, however, induce expected asymmetry effects either for the sample or individual participants. Even while systematic stimulus-dependent individual differences emerged in self-reports as well as LPP amplitudes, the asymmetry variability was dominated by stimulus-independent interindividual variability. Taken together with previous findings, these results suggest that under some circumstances anterior asymmetry may not be an inevitable consequence of core affect. Instead, state asymmetry shifts may be overpowered by stable trait asymmetry differences and/or stimulus-independent yet situation-dependent interindividual variability, possibly caused by processes such as emotion regulation or anxious apprehension.

  17. Interdependent Followers Prefer Avoidant Leaders: Followers’ Cultural Orientation Moderates Leaders’ Avoidance Relationships with Followers’ Work Outcomes

    Directory of Open Access Journals (Sweden)

    Konstantinos G. Kafetsios

    2018-03-01

    Full Text Available Several studies examining leader–follower interaction in Greece, a collectivistic culture, paradoxically find that leaders’ emotion suppression-related personality traits (attachment avoidance, emotion suppression, emotion control are associated with followers’ positive emotional and work attitude outcomes. These findings have been explained with reference to followers’ implicit cultural schemas, interdependence in particular. Yet, this conjuncture has not been directly tested. The present study directly examined, in a field setting, how followers’ independent and interdependent (cultural self-construal moderate the relationship between leaders’ attachment orientation and followers’ emotion and satisfaction outcomes at the work place. As hypothesized, leaders’ higher avoidance was associated with followers’ job satisfaction, group cohesion, and deep acting as well as lower negative affect and loneliness for followers higher on interdependent self-construal. The results underline perceptual processes involved in followers’ interdependent self-construal in relation to leaders’ emotion suppression-related traits.

  18. Economical Production of Pu-238

    Energy Technology Data Exchange (ETDEWEB)

    Steven D. Howe; Douglas Crawford; Jorge Navarro; Terry Ring

    2013-02-01

    All space exploration missions traveling beyond Jupiter must use radioisotopic power sources for electrical power. The best isotope to power these sources is plutonium-238. The US supply of Pu-238 is almost exhausted and will be gone within the next decade. The Department of Energy has initiated a production program with a $10M allocation from NASA but the cost is estimated at over $100 M to get to production levels. The Center for Space Nuclear Research has conceived of a potentially better process to produce Pu-238 earlier and for significantly less cost. The new process will also produce dramatically less waste. Potentially, the front end costs could be provided by private industry such that the government only had to pay for the product produced. Under a NASA Phase I NIAC grant, the CSNR has evaluated the feasibility of using a low power, commercially available nuclear reactor to produce at least 1.5 kg of Pu-238 per year. The impact on the neutronics of the reactor have been assessed, the amount of Neptunium target material estimated, and the production rates calculated. In addition, the size of the post-irradiation processing facility has been established. In addition, a new method for fabricating the Pu-238 product into the form used for power sources has been identified to reduce the cost of the final product. In short, the concept appears to be viable, can produce the amount of Pu-238 needed to support the NASA missions, can be available within a few years, and will cost significantly less than the current DOE program.

  19. Losses as ecological guides: minor losses lead to maximization and not to avoidance.

    Science.gov (United States)

    Yechiam, Eldad; Retzer, Matan; Telpaz, Ariel; Hochman, Guy

    2015-06-01

    Losses are commonly thought to result in a neuropsychological avoidance response. We suggest that losses also provide ecological guidance by increasing focus on the task at hand, and that this effect may override the avoidance response. This prediction was tested in a series of studies. In Study 1a we found that minor losses did not lead to an avoidance response. Instead, they guided participants to make advantageous choices (in terms of expected value) and to avoid disadvantageous choices. Moreover, losses were associated with less switching between options after the first block of exploration. In Study 1b we found that this effect was not simply a by-product of the increase in visual contrast with losses. In Study 1c we found that the effect of losses did not emerge when alternatives did not differ in their expected value but only in their risk level. In Study 2 we investigated the autonomic arousal dynamics associated with this behavioral pattern via pupillometric responses. The results showed increased pupil diameter following losses compared to gains. However, this increase was not associated with a tendency to avoid losses, but rather with a tendency to select more advantageously. These findings suggest that attention and reasoning processes induced by losses can out-weigh the influence of affective processes leading to avoidance. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. How biological microtubules may avoid decoherence

    International Nuclear Information System (INIS)

    Hameroff, S.

    2005-01-01

    Full text: Entangled superpositions persisting for hundreds of milliseconds in protein assemblies such as microtubules (MTs) are proposed in biological functions, e.g. quantum computation relevant to consciousness in the Penrose-Hameroff 'Orch OR' model. Cylindrical polymers of the protein tubulin, MTs organize cell activities. The obvious question is how biological quantum states could avoid decoherence, e.g. in the brain at 37.6 degrees centigrade. Screening/sheelding: tubulin protein states/functions are governed by van der Waals London forces, quantum interactions among clouds of delocalizable electrons in nonpolar 'hydrophobic' intra-protein pockets screened from external van der Waals thermal interactions. Such pockets include amino acid resonance structures benzene and indole rings. (Anesthetic gases erase consciousness solely by interfering with London forces in hydrophobic pockets in various brain proteins). Hence tubulin states may act as superpositioned qubits also shielded at the MT level by counter-ion Debye plasma layers (due to charged C-termini tails on tubulin) and by water-ordering actin gels which embed MTs in a quasi-solid. Biological systems may also exploit thermodynamic gradients to give extremely low effective temperatures. Decoherence free subspaces: paradoxically, a system coupled strongly to its environment through certain degrees of freedom can effectively 'freeze' other degrees of freedom (quantum Zeno effect), enabling coherent superpositions and entanglement to persist. Metabolic energy supplied to MT collective dynamics (e.g. Froehlich coherence) can cause Bose-Einstein condenzation and counter decoherence as lasers avoid decoherence at room temperature. Topological quantum error correction: MT lattice structure reveals various helical winding paths through adjacent tubulins which follow the Fibonacci series. Propagation/interactions of quasi-particles along these paths may process information. As proposed by Kitaev (1997), various

  1. A New Paradigm for Evaluating Avoidance/Escape Motivation.

    Science.gov (United States)

    Tsutsui-Kimura, Iku; Bouchekioua, Youcef; Mimura, Masaru; Tanaka, Kenji F

    2017-07-01

    Organisms have evolved to approach pleasurable opportunities and to avoid or escape from aversive experiences. These 2 distinct motivations are referred to as approach and avoidance/escape motivations and are both considered vital for survival. Despite several recent advances in understanding the neurobiology of motivation, most studies addressed approach but not avoidance/escape motivation. Here we develop a new experimental paradigm to quantify avoidance/escape motivation and examine the pharmacological validity. We set up an avoidance variable ratio 5 task in which mice were required to press a lever for variable times to avoid an upcoming aversive stimulus (foot shock) or to escape the ongoing aversive event if they failed to avoid it. We i.p. injected ketamine (0, 1, or 5 mg/kg) or buspirone (0, 5, or 10 mg/kg) 20 or 30 minutes before the behavioral task to see if ketamine enhanced avoidance/escape behavior and buspirone diminished it as previously reported. We found that the performance on the avoidance variable ratio 5 task was sensitive to the intensity of the aversive stimulus. Treatment with ketamine increased while that with buspirone decreased the probability of avoidance from an aversive stimulus in the variable ratio 5 task, being consistent with previous reports. Our new paradigm will prove useful for quantifying avoidance/escape motivation and will contribute to a more comprehensive understanding of motivation. © The Author 2017. Published by Oxford University Press on behalf of CINP.

  2. Avoiding unfavorable results in postburn contracture hand

    Science.gov (United States)

    Bhattacharya, Sameek

    2013-01-01

    Deformities of the hands are a fairly common sequel of burn especially in the developing world. This is because of high incidence of burns, limited access to standard treatment and rehabilitation. The best outcome of a burnt hand is when deformities are prevented from developing. A good functional result is possible when due consideration is paid to hands during resuscitation, excisional surgery, reconstructive surgery and physiotherapy. The post-burns deformities of hand develop due direct thermal damage or secondary to intrinsic minus position due to oedema or vascular insufficiency. During the acute phase the concerns are, maintenance circulation minimize oedema prevent unphysiological positioning and wound closure with autogenous tissue as soon as possible. The rehabilitation program during the acute phase starts from day one and goes on till the hand has healed and has regained full range of motion. Full blown hand contractures are challenging to correct and become more difficult as time passes. Long-standing cases often land up with attenuation of extensor apparatus leading to swan neck and boutonniere deformity, muscle shortening and bony ankylosis. The major and most common pitfall after contracture release is relapse. The treatment protocol of contracture is solely directed towards countering this tendency. This article aims to guide a surgeon in obtaining optimal hand function and avoid pit falls at different stages of management of hand burns. The reasons of an unfavourable outcome of a burnt hand are possible lack of optimal care in the acute phase, while planning and performing reconstructive procedure and during aftercare and rehabilitation. PMID:24501479

  3. Current strategies to avoid misdiagnosis of malaria.

    Science.gov (United States)

    Hänscheid, T

    2003-06-01

    Malaria remains the most important parasitic disease, and tens of thousands of cases are imported into non-endemic countries annually. However, any single institution may see only a very few cases-this is probably the reason why laboratory and clinical misdiagnosis may not be uncommon. In the laboratory, unfamiliarity with microscopic diagnosis may be the main reason, considering the large number of laboratory staff who provide on-call services, often without expert help at hand, as well as the difficulty in detecting cases with low-level parasitemia. Staff should therefore be provided with continuing microscopic training to maintain proficiency. The complementary use of immunochromatographic rapid detection tests (RDTs) may be useful, especially during on-call hours, although, in order to ensure correct interpretation, their inherent limitations have to be well known. Diagnosis based on the polymerase chain reaction is still unsuitable for routine use, due to its long turnaround time, its cost, and its unavailability outside regular hours, although it may be helpful in selected cases. Once the alert clinician has considered the possibility of malaria, and suspicion continues to be high, malaria can be excluded by repeat smears or RDTs. However, the absence of clinical suspicion may not be infrequent, and may have more serious consequences. Depending on the local number of malaria cases seen, laboratory staff should have a low threshold for the decision to perform unsolicited malaria diagnostic tests on suspicious samples, especially if other laboratory tests are abnormal (e.g. thrombocytopenia, presence of atypical lymphocytes, or raised lactate dehydrogenase). The detection of intraleukocytic hemozoin during automated full blood counts is a promising new way to avoid misdiagnosis of clinically unsuspected malaria.

  4. Traditional Use and Avoidance of Foods of Animal Origin: A Culture Historical View

    Science.gov (United States)

    Simoons, Frederick J.

    1978-01-01

    This article discusses pork avoidance in the Near East, the sacred cow concept of Hinduism, the use of horsemeat in Western Europe, the rejection of fish as human food in Africa and Asia, and the use of milk and dairy products. (Author/BB)

  5. Avoiding Drought Risks and Social Conflict Under Climate Change

    Science.gov (United States)

    Towler, E.; Lazrus, H.; Paimazumder, D.

    2014-12-01

    Traditional drought research has mainly focused on physical drought risks and less on the cultural processes that also contribute to how drought risks are perceived and managed. However, as society becomes more vulnerable to drought and climate change threatens to increase water scarcity, it is clear that drought research would benefit from a more interdisciplinary approach. To assess avoided drought impacts from reduced climate change, drought risks need to be assessed in the context of both climate prediction as well as improved understanding of socio-cultural processes. To this end, this study explores a risk-based framework to combine physical drought likelihoods with perceived risks from stakeholder interviews. Results are presented from a case study on how stakeholders in south-central Oklahoma perceive drought risks given diverse cultural beliefs, water uses, and uncertainties in future drought prediction. Stakeholder interviews (n=38) were conducted in 2012 to understand drought risks to various uses of water, as well as to measure worldviews from the cultural theory of risk - a theory that explains why people perceive risks differently, potentially leading to conflict over management decisions. For physical drought risk, drought projections are derived from a large ensemble of future climates generated from two RCPs that represent higher and lower emissions trajectories (i.e., RCP8.5 and RCP4.5). These are used to develop a Combined Drought Risk Matrix (CDRM) that characterizes drought risks for different water uses as the products of both physical likelihood (from the climate ensemble) and risk perception (from the interviews). We use the CRDM to explore the avoided drought risks posed to various water uses, as well as to investigate the potential for reduction of conflict over water management.

  6. Surface Loving and Surface Avoiding modes

    OpenAIRE

    Combe, Nicolas; Huntzinger, Jean Roch; Morillo, Joseph

    2008-01-01

    International audience; We theoretically study the propagation of sound waves in GaAs/AlAs superlattices focussing on periodic modes in the vicinity of the band gaps. Based on analytical and numerical calculations, we show that these modes are the product of a quickly oscillating function times a slowly varying envelope function. We carefully study the phase of the envelope function compared to the surface of a semi-infinite superlattice. Especially, the dephasing of the superlattice compared...

  7. Avoid costly mistakes of the past.

    Science.gov (United States)

    Halley, Marc D

    2013-03-01

    Physician employment is here to stay. The challenge for healthcare finance professionals is to make physician relationships work without the financial losses experienced by hospitals that tried physician employment in the past. Capturing market share should be a key strategy in any physician employment effort. Physicians who are engaged and actively involved in the process make great business partners because they understand the productivity, efficiencies, and cost controls needed to succeed.

  8. A chance to avoid mistakes human error

    International Nuclear Information System (INIS)

    Amaro, Pablo; Obeso, Eduardo; Gomez, Ruben

    2010-01-01

    Trying to give an answer to the lack of public information in the industry, in relationship with the different tools that are managed in the nuclear industry for minimizing the human error, a group of workers from different sections of the St. Maria de Garona NPP (Quality Assurance/ Organization and Human Factors) decided to embark on a challenging and exciting project: 'Write a book collecting all the knowledge accumulated during their daily activities, very often during lecture time of external information received from different organizations within the nuclear industry (INPO, WANO...), but also visiting different NPP's, maintaining meetings and participating in training courses related de Human and Organizational Factors'. Main objective of the book is presenting to the industry in general, the different tools that are used and fostered in the nuclear industry, in a practical way. In this way, the assimilation and implementation in others industries could be possible and achievable in and efficient context. One year of work, and our project is a reality. We have presented and abstract during the last Spanish Nuclear Society meeting in Sevilla, last October...and the best, the book is into the market for everybody in web-site: www.bubok.com. The book is structured in the following areas: 'Errare humanum est': Trying to present what is the human error to the reader, its origin and the different barriers. The message is that the reader see the error like something continuously present in our lives... even more frequently than we think. Studying its origin can be established aimed at barriers to avoid or at least minimize it. 'Error's bitter face': Shows the possible consequences of human errors. What better that presenting real experiences that have occurred in the industry. In the book, accidents in the nuclear industry, like Tree Mile Island NPP, Chernobyl NPP, and incidents like Davis Besse NPP in the past, helps to the reader to make a reflection about the

  9. Towards better patient care: drugs to avoid.

    Science.gov (United States)

    2013-04-01

    Common sense dictates that one should choose tried and tested drugs with proven, concrete benefits that outweigh their adverse effects. Many new drugs are approved each year, often despite a lack of solid evidence that they are any better than existing treatments. Worse, some are approved despite being less effective or more harmful than current options. Massive promotion is used to ensure that such drugs achieve a positive image in the eyes of healthcare professionals and patients. Renowned "opinion leaders" intervene in their favour at conferences and in specialist media, and their opinions are further propagated by specialists in the field. Finally, campaigns in the lay media are used to highlight the target illness, encouraging patients to request a prescription. New data sometimes show that older, initially promising drugs are less effective or more harmful than first thought. For all these reasons, many drugs that are now present on the market are more harmful than beneficial and should be avoided. Unfortunately, negative assessment data and warnings are often drowned in the flood of promotion and advertising. Front-line healthcare professionals who are determined to act in their patients' best interests can find themselves swimming against a tide of specialist opinion, marketing authorisation, and reimbursement decisions. By leaving drugs that are more harmful than beneficial on the market and contenting themselves with simple half-measures, healthcare authorities are failing in their duty to protect patients. Prescrire, a journal funded solely by its subscribers, does not seek to do the work of health authorities, and does not have the means to do so. Prescrire's goal is simply to help healthcare professionals provide better care. The following text lists the principal drugs that we consider more harmful than beneficial, based on our reviews published between 2010 and 2012 in our French edition. These drugs should not be used. Patients and healthcare

  10. Enemy avoidance task: A novel behavioral paradigm for assessing spatial avoidance of a moving subject

    Czech Academy of Sciences Publication Activity Database

    Telenský, Petr; Svoboda, Jan; Pašťálková, Eva; Blahna, Karel; Bureš, Jan; Stuchlík, Aleš

    2009-01-01

    Roč. 180, č. 1 (2009), s. 29-33 ISSN 0165-0270 R&D Projects: GA ČR(CZ) GA309/07/0341; GA ČR(CZ) GA309/09/0286; GA ČR(CZ) GD206/05/H012; GA AV ČR(CZ) KJB500110904 Institutional research plan: CEZ:AV0Z50110509 Keywords : avoidance * moving subject * learning Subject RIV: FH - Neuro logy Impact factor: 2.295, year: 2009

  11. Excise Tax Avoidance: The Case of State Cigarette Taxes

    Science.gov (United States)

    DeCicca, Philip; Kenkel, Donald; Liu, Feng

    2013-01-01

    We conduct an applied welfare economics analysis of cigarette tax avoidance. We develop an extension of the standard formula for the optimal Pigouvian corrective tax to incorporate the possibility that consumers avoid the tax by making purchases in nearby lower-tax jurisdictions. To provide a key parameter for our formula, we estimate a structural endogenous switching regression model of border-crossing and cigarette prices. In illustrative calculations, we find that for many states, after taking into account tax avoidance the optimal tax is at least 20 percent smaller than the standard Pigouvian tax that simply internalizes external costs. Our empirical estimate that tax avoidance strongly responds to the price differential is the main reason for this result. We also use our results to examine the benefits of replacing avoidable state excise taxes with a harder-to-avoid federal excise tax on cigarettes. PMID:24140760

  12. Excise tax avoidance: the case of state cigarette taxes.

    Science.gov (United States)

    DeCicca, Philip; Kenkel, Donald; Liu, Feng

    2013-12-01

    We conduct an applied welfare economics analysis of cigarette tax avoidance. We develop an extension of the standard formula for the optimal Pigouvian corrective tax to incorporate the possibility that consumers avoid the tax by making purchases in nearby lower tax jurisdictions. To provide a key parameter for our formula, we estimate a structural endogenous switching regression model of border-crossing and cigarette prices. In illustrative calculations, we find that for many states, after taking into account tax avoidance the optimal tax is at least 20% smaller than the standard Pigouvian tax that simply internalizes external costs. Our empirical estimate that tax avoidance strongly responds to the price differential is the main reason for this result. We also use our results to examine the benefits of replacing avoidable state excise taxes with a harder-to-avoid federal excise tax on cigarettes. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Avoidance-related EEG asymmetry predicts circulating interleukin-6.

    Science.gov (United States)

    Shields, Grant S; Moons, Wesley G

    2016-03-01

    Recent research has linked avoidance-oriented motivational states to elevated pro-inflammatory cytokine levels. According to one of many theories regarding the association between avoidance and cytokine levels, because the evolutionarily basic avoidance system may be activated when an organism is threatened or overwhelmed, an associated inflammatory response may be adaptive for dealing with potential injury in such threatening situations. To examine this hypothesis, we tested whether the neural correlate of avoidance motivation associates with baseline levels of the circulating pro-inflammatory cytokine interleukin-6 (IL-6). Controlling for covariates, greater resting neural activity in the right frontal cortex relative to the left frontal cortex-the neural correlate of avoidance motivation-was associated with baseline IL-6. These results thus support the hypothesis that the avoidance motivational system may be closely linked to systemic inflammatory activity. (c) 2016 APA, all rights reserved).

  14. Challenges in Identifying Effects and Determinants of Corporate Tax Avoidance

    OpenAIRE

    Hüsecken, Birgit

    2017-01-01

    Policymakers worldwide try to hinder tax avoidance. In order to implement effective tax regulations, it is essential to completely understand why corporations avoid taxes and why some appear to be more effective than others. However, various challenges in identifying effects and determinants of corporate tax avoidance cause knowledge gaps. This thesis consists of three essays highlighting the necessity of refined identification strategies. The first essay “The Undersheltering Puzzle and its P...

  15. To approach or to avoid: neurobiological mechanisms in social anxiety

    OpenAIRE

    Peer, Jacobien Marit van

    2009-01-01

    We investigated the role of cortisol (an important stress-hormone) in the regulation of social fear and avoidance behavior in socially anxious individuals, which are characterized by extreme fear and avoidance of social situations. Previous studies in animals and children showed a relation between increased fearfulness and avoidance and elevated cortisol levels, but the causal role of cortisol in these processes is not known. We found that, only in high socially anxious participants, cortisol...

  16. Pengaruh Ukuran Perusahaan terhadap Aggressive Tax Avoidance di Indonesia

    OpenAIRE

    M. Khoiru Rusydi

    2013-01-01

    This study aims to empirically examine the effect of firm size (Firm Size) against aggressive tax avoidance (aggressive tax avoidance) in Indonesia. The method in use is descriptive quantitative with panel data of financial statements of listed companies on the Stock Exchange in the period 2010-2012 which regresswith Eviews program. The results of this study indicate that company size has no effect on aggressive tax avoidance in Indonesia, which means that the behavior of firms in Indonesia f...

  17. Deforestation, Leakage and Avoided Deforestation Policies: A Spatial Analysis

    OpenAIRE

    Philippe Delacote; Elizabeth J. Z. Robinson; Sébastien Roussel

    2015-01-01

    This paper analyses the impact of several avoided deforestation policies within a patchy forested landscape. Central is the idea that one neighbour's deforestation actions may impact the returns to deforestation in nearby patches. We determine the impact of each policy in terms of avoided deforestation and leakage levels at the landscape scale through modelling and simulations. Avoided deforestation policies at a landscape level are respectively: two Payment for Environmental Services (PES) p...

  18. The Effect of Tax Rates on Fiscal Evasion and Avoidance

    OpenAIRE

    Mentor Gashi; Halil Kukaj

    2016-01-01

    Abstract:In order to findelements that destimulate fiscal evasion or avoidance, we have submitted six elements, through the questionnaire, to determine which elements are that destimulate the fiscal evasion and avoidance, and evaluate their impact.This paper is focused in customs duty avoidance.The elements that we have submitted to evaluate their power, are: Powerful control during customs clearance, more efficient post clearance control, probability of subject investigation, higher fines, l...

  19. Universality of collapsing two-dimensional self-avoiding trails

    International Nuclear Information System (INIS)

    Foster, D P

    2009-01-01

    Results of a numerically exact transfer matrix calculation for the model of interacting self-avoiding trails are presented. The results lead to the conclusion that at the collapse transition, self-avoiding trails are in the same universality class as the O(n = 0) model of Bloete and Nienhuis (or vertex-interacting self-avoiding walk), which has thermal exponent ν = 12/23, contrary to previous conjectures. (fast track communication)

  20. Good Corporate Governance dan Ukuran Perusahaan Pengaruhnya Pada Tax Avoidance

    Directory of Open Access Journals (Sweden)

    Vivi Adeyani Tandean

    2016-01-01

    Full Text Available This study aims to examine empirically the effect of the application of GCG and the size of the company on tax avoidance. This study was performed on companies listed on the Stock Exchange 2010-2013. Variables used are institutional ownership, the independence of auditors, the audit committee, and the size of the company as an independent variable and tax avoidance as the dependent variable. The research sample 84 manufacturing companies. The sampling technique using judgment sampling. Testing data using multiple regression analysis. The test results showed that only affects the audit committee on tax avoidance. Keywords: Corporate governance, size, tax avoidance

  1. Pengaruh Ukuran Perusahaan terhadap Aggressive Tax Avoidance di Indonesia

    Directory of Open Access Journals (Sweden)

    M. Khoiru Rusydi

    2013-08-01

    Full Text Available This study aims to empirically examine the effect of firm size (Firm Size against aggressive tax avoidance (aggressive tax avoidance in Indonesia. The method in use is descriptive quantitative with panel data of financial statements of listed companies on the Stock Exchange in the period 2010-2012 which regresswith Eviews program. The results of this study indicate that company size has no effect on aggressive tax avoidance in Indonesia, which means that the behavior of firms in Indonesia for more aggressive tax avoidance do not affect the size of the company.

  2. Evidence for an expectancy-based theory of avoidance behaviour.

    Science.gov (United States)

    Declercq, Mieke; De Houwer, Jan; Baeyens, Frank

    2008-01-01

    In most studies on avoidance learning, participants receive an aversive unconditioned stimulus after a warning signal is presented, unless the participant performs a particular response. Lovibond (2006) recently proposed a cognitive theory of avoidance learning, according to which avoidance behaviour is a function of both Pavlovian and instrumental conditioning. In line with this theory, we found that avoidance behaviour was based on an integration of acquired knowledge about, on the one hand, the relation between stimuli and, on the other hand, the relation between behaviour and stimuli.

  3. What you want to avoid is what you see: Social avoidance motivation affects the interpretation of emotional faces

    OpenAIRE

    Nikitin, Jana; Freund, Alexandra M

    2015-01-01

    This study investigated the effects of habitual social approach and avoidance motivation on the classification of facial expressions of different visual clarity. Participants (N = 78) categorized partially masked emotional faces expressing either anger or happiness as positive or negative. Participants generally tended to interpret the facial expressions in a positive way. This positivity effect was reduced when persons were highly avoidance motivated. Social avoidance motivation predicted fe...

  4. Lack of behavioural evidence for kin avoidance in mate choice in a hymenopteran parasitoid (Hymenoptera: Braconidae).

    Science.gov (United States)

    Bourdais, D; Hance, T

    2009-05-01

    Mechanisms for inbreeding avoidance should be prevalent in insects that reproduce by arrhenotokous haplodiploidy because of the higher potential production of unviable diploid males in inbred matings. Few studies have focused on mating strategies in insect parasitoids and even less on kinship relationships during mate choice. In this study we tested avoidance of kin as mate in the parasitic wasp Aphidius matricariae (Hymenoptera: Braconidae) using an ethological approach. Key mating parameters, such as male wing fanning, latent period before genitalia contact and duration of copulation were measured. No evidence for kin avoidance in mate choice in both A. matricariae males and females was observed in our behaviour (no choice or choice tests) tests. This lack of ethological sib mating avoidance could be due to different factors such as sex determination rule different than the single locus complementary sex determination, making lower the proportion of diploid males in case of sib matings and thus its negative consequence. The existence of other inbreeding avoidance strategies and mechanisms that reduce the probability of 2 receptive relatives meeting in nature may be common, for example, inbred mating may be rare through differential dispersal, delayed maturation, or protandry.

  5. The mnemonic mover : Nostalgia regulates avoidance and approach motivation

    NARCIS (Netherlands)

    Stephan, E.; Wildschut, T.; Sedikides, C.; Zhou, X.; Zu, W.; Routledge, C.; Cheung, W.-Y.; Vingerhoets, A.J.J.M.

    2014-01-01

    In light of its role in maintaining psychological equanimity, we proposed that nostalgia—a self-relevant, social, and predominantly positive emotion—regulates avoidance and approach motivation. We advanced a model in which (a) avoidance motivation triggers nostalgia and (b) nostalgia, in turn,

  6. Five-Yearly Review: TREF avoids the worst!

    CERN Multimedia

    Staff Association

    2006-01-01

    In our last edition, we informed you about the Staff Council decision to reject the entire set of proposals for the five-yearly review, on the basis of the Director-General's revised proposals 2 and 10. We also indicated that a total failure could still be avoided at TREF on 4 and 5 October. To our relief, TREF avoided the worst!

  7. To approach or to avoid : neurobiological mechanisms in social anxiety

    NARCIS (Netherlands)

    Peer, Jacobien Marit van

    2009-01-01

    We investigated the role of cortisol (an important stress-hormone) in the regulation of social fear and avoidance behavior in socially anxious individuals, which are characterized by extreme fear and avoidance of social situations. Previous studies in animals and children showed a relation between

  8. Assessment and Implications of Social Avoidance in Chinese Early Adolescents

    Science.gov (United States)

    Sang, Biao; Ding, Xuechen; Coplan, Robert J.; Liu, Junsheng; Pan, Tingting; Feng, Xingyi

    2018-01-01

    The goals of the present study were to (a) develop and validate a new self-report measure of social avoidance for use among early adolescents in mainland China and (b) explore the links between subtypes of social withdrawal (i.e., shyness, unsociability, and social avoidance) and indices of socio-emotional difficulties in this cultural context.…

  9. 20 CFR 606.23 - Avoidance of tax credit reduction.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Avoidance of tax credit reduction. 606.23 Section 606.23 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR TAX CREDITS... Tax Credit Reduction § 606.23 Avoidance of tax credit reduction. (a) Applicability. Subsection (g) of...

  10. 20 CFR 606.24 - Application for avoidance.

    Science.gov (United States)

    2010-04-01

    ... respect to which a State requests avoidance of tax credit reduction. The Governor is required to notify... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Application for avoidance. 606.24 Section 606.24 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR TAX CREDITS UNDER...

  11. 26 CFR 20.2107-1 - Expatriation to avoid tax.

    Science.gov (United States)

    2010-04-01

    ... principal purpose) the avoidance of Federal income, estate, or gift tax. Section 301(b) of the Immigration... 26 Internal Revenue 14 2010-04-01 2010-04-01 false Expatriation to avoid tax. 20.2107-1 Section 20... GIFT TAXES ESTATE TAX; ESTATES OF DECEDENTS DYING AFTER AUGUST 16, 1954 Estates of Nonresidents Not...

  12. 78 FR 35262 - Detection and Avoidance of Counterfeit Electronic Parts

    Science.gov (United States)

    2013-06-12

    ... experts and interested parties in Government and the private sector regarding the electronic parts... Avoidance of Counterfeit Electronic Parts AGENCY: Defense Acquisition Regulations System, Department of... interested parties in Government and the private sector about the requirements for detection and avoidance of...

  13. 28 CFR 552.23 - Confrontation avoidance procedures.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Confrontation avoidance procedures. 552... MANAGEMENT CUSTODY Use of Force and Application of Restraints on Inmates § 552.23 Confrontation avoidance... information about the inmate and the immediate situation. Based on their assessment of that information, they...

  14. Posture as index for approach-avoidance behavior

    NARCIS (Netherlands)

    Eerland, A.; Guadalupe, Tulio; Franken, Ingmar; Zwaan, Rolf

    2012-01-01

    Approach and avoidance are two behavioral responses that make people tend to approach positive and avoid negative situations. This study examines whether postural behavior is influenced by the affective state of pictures. While standing on the Wii™ Balance Board, participants viewed pleasant,

  15. Posture as index for Approach-Avoidance behavior

    NARCIS (Netherlands)

    A. Eerland (Anita); T. Guadalupe (Tulio); I.H.A. Franken (Ingmar); R.A. Zwaan (Rolf)

    2012-01-01

    textabstractApproach and avoidance are two behavioral responses that make people tend to approach positive and avoid negative situations. This study examines whether postural behavior is influenced by the affective state of pictures. While standing on the Wii™ Balance Board, participants viewed

  16. 5 CFR 950.109 - Avoidance of conflict of interest.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Avoidance of conflict of interest. 950... PRIVATE VOLUNTARY ORGANIZATIONS General Provisions § 950.109 Avoidance of conflict of interest. Any... affiliation with a charitable organization, there could be or appear to be a conflict of interest under any...

  17. Comparing empirical results of transaction avoidance rules studies

    NARCIS (Netherlands)

    van Dijck, G.

    2008-01-01

    Empirical legal research in the UK and in the Netherlands has provided data on the extent to which the transaction avoidance rules (avoidance powers, actio Pauliana) generate practical problems. This article’s goal is to explore the similarities and differences of the data. To achieve this, existing

  18. Design study of general aviation collision avoidance system

    Science.gov (United States)

    Bates, M. R.; Moore, L. D.; Scott, W. V.

    1972-01-01

    The selection and design of a time/frequency collision avoidance system for use in general aviation aircraft is discussed. The modifications to airline transport collision avoidance equipment which were made to produce the simpler general aviation system are described. The threat determination capabilities and operating principles of the general aviation system are illustrated.

  19. Twenty Common Testing Mistakes for EFL Teachers to Avoid

    Science.gov (United States)

    Henning, Grant

    2012-01-01

    To some extent, good testing procedure, like good language use, can be achieved through avoidance of errors. Almost any language-instruction program requires the preparation and administration of tests, and it is only to the extent that certain common testing mistakes have been avoided that such tests can be said to be worthwhile selection,…

  20. Electronic and magnetic properties study of neptunium compounds: NpX{sub 3} and Np{sub 2}T{sub 2}X by Moessbauer effect, neutrons diffraction and Squid magnetometry; Etude des proprietes magnetiques et electroniques de composes de neptunium NpX{sub 3} et Np{sub 2}T{sub 2}X par spectrometrie mossbauer, diffraction de neutrons et magnetometrie squid

    Energy Technology Data Exchange (ETDEWEB)

    Colineau, E.

    1996-07-11

    This work is a contribution to the study of magnetic and electronic properties of the intermetallic compounds: NpX{sub 3} (X= Al, Ga, In, Sn) and Np{sub 2}T{sub 2}X (T= Co, Ni, Ru, Rh, Pd, Pt; X= In, Sn). These properties have been determined by Moessbauer effect, neutron diffraction and Squid magnetometry. The obtained results for NpX{sub 3} show particularly that NpAl{sub 3} orders in a type II (k= 1/2 1/2 1/2) antiferromagnetic structure at T{sub N} {approx_equal} 37 K. The antiferromagnetic phase NpGa{sub 3} orders in a type II too and the magnetic moments carried by neptunium in the ferromagnetic phase are oriented along the (111) axes. The two NpIN{sub 3} magnetic phases observed by Moessbauer effect (4.2 K-10 K and 10 K- 14 K) are identified by neutron diffraction as ferromagnetic and antiferromagnetic (k= 3/8 3/8 3/8). In this last phase the moments are oriented along the (111) axes. The magnetization measures on monocrystals show a weak anisotropy with (111) at all the temperatures and reveal the presence of a third magnetic phase between 8.2 and 10 K. At last, the fundamental state of the compounds NpAl{sub 3}, NpGa{sub 3} and NpIn{sub 3} is attributed to the {Gamma}{sub 5} crystal field and the strong reduction of the ordered moment in NpSn{sub 3} to a Kondo effect. Concerning the Np{sub 2}T{sub 2}X compounds, the Moessbauer effect measures have revealed that eight of these compounds order and three do not order. (O.M.). 239 refs.

  1. A Robust Obstacle Avoidance for Service Robot Using Bayesian Approach

    Directory of Open Access Journals (Sweden)

    Widodo Budiharto

    2011-03-01

    Full Text Available The objective of this paper is to propose a robust obstacle avoidance method for service robot in indoor environment. The method for obstacles avoidance uses information about static obstacles on the landmark using edge detection. Speed and direction of people that walks as moving obstacle obtained by single camera using tracking and recognition system and distance measurement using 3 ultrasonic sensors. A new geometrical model and maneuvering method for moving obstacle avoidance introduced and combined with Bayesian approach for state estimation. The obstacle avoidance problem is formulated using decision theory, prior and posterior distribution and loss function to determine an optimal response based on inaccurate sensor data. Algorithms for moving obstacles avoidance method proposed and experiment results implemented to service robot also presented. Various experiments show that our proposed method very fast, robust and successfully implemented to service robot called Srikandi II that equipped with 4 DOF arm robot developed in our laboratory.

  2. Posture as index for approach-avoidance behavior.

    Directory of Open Access Journals (Sweden)

    Anita Eerland

    Full Text Available Approach and avoidance are two behavioral responses that make people tend to approach positive and avoid negative situations. This study examines whether postural behavior is influenced by the affective state of pictures. While standing on the Wii™ Balance Board, participants viewed pleasant, neutral, and unpleasant pictures (passively viewing phase. Then they had to move their body to the left or the right (lateral movement phase to make the next picture appear. We recorded movements in the anterior-posterior direction to examine approach and avoidant behavior. During passively viewing, people approached pleasant pictures. They avoided unpleasant ones while they made a lateral movement. These findings provide support for the idea that we tend to approach positive and avoid negative situations.

  3. Collision avoidance for multiple Lagrangian dynamical systems with gyroscopic forces

    Directory of Open Access Journals (Sweden)

    Lorenzo Sabattini

    2017-01-01

    Full Text Available This article introduces a novel methodology for dealing with collision avoidance for groups of mobile robots. In particular, full dynamics are considered, since each robot is modeled as a Lagrangian dynamical system moving in a three-dimensional environment. Gyroscopic forces are utilized for defining the collision avoidance control strategy: This kind of forces leads to avoiding collisions, without interfering with the convergence properties of the multi-robot system’s desired control law. Collision avoidance introduces, in fact, a perturbation on the nominal behavior of the system: We define a method for choosing the direction of the gyroscopic force in an optimal manner, in such a way that perturbation is minimized. Collision avoidance and convergence properties are analytically demonstrated, and simulation results are provided for validation purpose.

  4. Assessing competition avoidance as a basic personality dimension.

    Science.gov (United States)

    Ryckman, Richard M; Thornton, Bill; Gold, Joel A

    2009-03-01

    The lack of an adequate psychometric instrument has impeded personality theory testing in the area of competition avoidance. The authors conducted 6 studies in an attempt to remedy this deficiency by constructing an individual-difference measure of competition avoidance. In line with K. Horney's (1937) interpersonal theory of neurosis, participants who were higher in competition avoidance showed higher levels of neuroticism, greater fears of both success and failure, a lower desire to prove themselves in competitive situations, higher levels of self-handicapping, and more maladaptiveness than those participants who were lower in competition avoidance. Also, they were more modest and willing to conform to group standards than were those lower in competition avoidance. The authors discuss the measure's potential usefulness as a diagnostic and assessment tool in academic, athletic, and clinical settings.

  5. Neural substrates of approach-avoidance conflict decision-making

    Science.gov (United States)

    Aupperle, Robin L.; Melrose, Andrew J.; Francisco, Alex; Paulus, Martin P.; Stein, Murray B.

    2014-01-01

    Animal approach-avoidance conflict paradigms have been used extensively to operationalize anxiety, quantify the effects of anxiolytic agents, and probe the neural basis of fear and anxiety. Results from human neuroimaging studies support that a frontal-striatal-amygdala neural circuitry is important for approach-avoidance learning. However, the neural basis of decision-making is much less clear in this context. Thus, we combined a recently developed human approach-avoidance paradigm with functional magnetic resonance imaging (fMRI) to identify neural substrates underlying approach-avoidance conflict decision-making. Fifteen healthy adults completed the approach-avoidance conflict (AAC) paradigm during fMRI. Analyses of variance were used to compare conflict to non-conflict (avoid-threat and approach-reward) conditions and to compare level of reward points offered during the decision phase. Trial-by-trial amplitude modulation analyses were used to delineate brain areas underlying decision-making in the context of approach/avoidance behavior. Conflict trials as compared to the non-conflict trials elicited greater activation within bilateral anterior cingulate cortex (ACC), anterior insula, and caudate, as well as right dorsolateral prefrontal cortex. Right caudate and lateral PFC activation was modulated by level of reward offered. Individuals who showed greater caudate activation exhibited less approach behavior. On a trial-by-trial basis, greater right lateral PFC activation related to less approach behavior. Taken together, results suggest that the degree of activation within prefrontal-striatal-insula circuitry determines the degree of approach versus avoidance decision-making. Moreover, the degree of caudate and lateral PFC activation is related to individual differences in approach-avoidance decision-making. Therefore, the AAC paradigm is ideally suited to probe anxiety-related processing differences during approach-avoidance decision-making. PMID:25224633

  6. Fission Product Library and Resource

    Energy Technology Data Exchange (ETDEWEB)

    Burke, J. T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Padgett, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-09-29

    Fission product yields can be extracted from an irradiated sample by performing gamma ray spectroscopy on the whole sample post irradiation. There are several pitfalls to avoid when trying to determine a specific isotope's fission product yield.

  7. Fostering design for avoiding small parts in commonly used objects.

    Science.gov (United States)

    de Koning, Ton; Foltran, Francesca; Gregori, Dario

    2012-05-14

    Injuries due to the accidental ingestion or aspiration of small parts have became a matter of interest in the last 30 years, focusing on the relationship between a proper prevention and the diminished frequency of occurrences. Small parts in commonly used objects represent a large sector of potential danger, taking explicit mouthing behavior of children in the first four years of life. In this paper the intent is to show the current situation of design projects and legislation around the world, meant to avoid the casual accidents due to manufacturing reasons. Proposed process and quality control standards seek to eliminate production errors and control materials to avoid deviation from the design. The present study draws its data from the Susy Safe registry, a European Commission co-funded project started in February 2005, whose aim is to establish an international registry of cases of Foreign Bodies (FB) injuries in children aged 0-14 years. Information collected from the data base concern age and gender of the child, location, shape, volume, consistency and elipticity of the foreign body, any complication occurred, hospitalization, and behavioral aspects linked to the injury, like the supervision of the parents or the activity concomitant to the injury. Cases are prospectively collected using the Susy Safe system from 06/2005; moreover, also information regarding past consecutive cases available in each center adhering to the project have been entered in the Susy Safe Registry. Data evidenced that the majority of small parts related injuries are related to stationery. The majority of objects (56.7%), were located in the nose, followed by the ears (31.5%). The distribution on incidence of FB injuries by age class shows that the majority of injuries due to small parts in common objects occurred in children older than >3 years. Male and female were affected with the same frequency when concerning the nose, while all other locations showed a higher frequency in males

  8. Reduction in Memory Specificity Following an Approach/Avoidance Scrambled Sentences Task Relates to Cognitive Avoidant Coping

    Science.gov (United States)

    Debeer, Elise; Raes, Filip; Williams, J. Mark G.; Hermans, Dirk

    2013-01-01

    "Overgeneral autobiographical memory" (OGM) refers to the tendency to retrieve less specific personal memories. According to the functional avoidance hypothesis, OGM might act as a cognitive strategy to avoid emotionally distressing details of negative memories. In the present study, we investigated the effect of an experimentally…

  9. Avoidance response of Enchytraeus albidus in relation to carbendazim ageing

    International Nuclear Information System (INIS)

    Kobeticova, Klara; Hofman, Jakub; Holoubek, Ivan

    2009-01-01

    In this study, avoidance response of Enchytraeus albidus to LUFA 2.2 soil contaminated with pesticide carbendazim was investigated. The aim was to clarify minimal test duration and temporal changes in avoidance response due to contamination ageing. Firstly, the concentration causing 50% avoidance (EC 50 ) was determined as 7.6 mg/kg. Then, test duration needed to reach this value (ET 50 = approximately 18 h) was identified. Finally, the capability of E. albidus avoidance test to reflect the changes of pollutant bioavailability was tested. The soil was spiked with carbendazim at the EC 50 concentration 1, 14, or 28 days before the test started and avoidance effects of fresh versus aged contamination were compared. The results indicated that enchytraeids preferred soil contaminated for 28 days prior to assay where carbendazim was probably less bioavailable than in freshly spiked soil. Our results open an interesting research area of potential use of avoidance tests for contaminant bioavailability assessment. - The results of this study show that avoidance response of Enchytraeus albidus might identify changes of contaminant bioavailability

  10. The role of social cognition in parasite and pathogen avoidance.

    Science.gov (United States)

    Kavaliers, Martin; Choleris, Elena

    2018-07-19

    The acquisition and use of social information are integral to social behaviour and parasite/pathogen avoidance. This involves social cognition which encompasses mechanisms for acquiring, processing, retaining and acting on social information. Social cognition entails the acquisition of social information about others (i.e. social recognition) and from others (i.e. social learning). Social cognition involves assessing other individuals and their infection status and the pathogen and parasite threat they pose and deciding about when and how to interact with them. Social cognition provides a framework for examining pathogen and parasite avoidance behaviours and their associated neurobiological mechanisms. Here, we briefly consider the relationships between social cognition and olfactory-mediated pathogen and parasite avoidance behaviours. We briefly discuss aspects of (i) social recognition of actual and potentially infected individuals and the impact of parasite/pathogen threat on mate and social partner choice; (ii) the roles of 'out-groups' (strangers, unfamiliar individuals) and 'in-groups' (familiar individuals) in the expression of parasite/pathogen avoidance behaviours; (iii) individual and social learning, i.e. the utilization of the pathogen recognition and avoidance responses of others; and (iv) the neurobiological mechanisms, in particular the roles of the nonapeptide, oxytocin and steroid hormones (oestrogens) associated with social cognition and parasite/pathogen avoidance.This article is part of the Theo Murphy meeting issue 'Evolution of pathogen and parasite avoidance behaviours'. © 2018 The Author(s).

  11. On the role of subsecond dopamine release in conditioned avoidance

    Directory of Open Access Journals (Sweden)

    Erik B Oleson

    2013-06-01

    Full Text Available Using shock avoidance procedures to study conditioned behavioral responses has a rich history within the field of experimental psychology. Such experiments led to the formulation of the general concept of negative reinforcement and specific theories attempting to explain escape and avoidance behavior, or why animals choose to either terminate or prevent the presentation of an aversive event. For example, the two-factor theory of avoidance holds that cues preceding an aversive event begin to evoke conditioned fear responses, and these conditioned fear responses reinforce the instrumental avoidance response. Current neuroscientific advances are providing new perspectives into this historical literature. Due to its well-established role in reinforcement processes and behavioral control, the mesolimbic dopamine system presented itself as a logical starting point in the search for neural correlates of avoidance and escape behavior. We recently demonstrated that phasic dopamine release events are inhibited by stimuli associated with aversive events but increased by stimuli preceding the successful avoidance of the aversive event. The latter observation is inconsistent with the second component of the two-factor theory of avoidance and; therefore, led us propose a new theoretical explanation of conditioned avoidance: 1 fear is initially conditioned to the warning signal and dopamine computes this fear association as a decrease in release, 2 the warning signal, now capable of producing a negative emotional state, suppresses dopamine release and behavior, 3 over repeated trials the warning signal becomes associated with safety rather than fear; dopaminergic neurons already compute safety as an increase in release and begin to encode the warning signal as the earliest predictor of safety 4 the warning signal now promotes conditioned avoidance via dopaminergic modulation of the brain’s incentive-motivational circuitry.

  12. Strategic mistakes (AVOIDABLE) The topicality of Michel Porter’s generic strategies

    OpenAIRE

    Viltard, Leandro Adolfo

    2017-01-01

    This article explores the topicality of Porter’s generic strategies, assessing about their applicability on two specific automotive industry projects: The Smart and the New Beetle.   After performing a documentation analysis on these two projects, it was concluded that both of them may be considered avoidable strategic mistakes as they show the risks of higher differentiation that is not being paid by the customer, no matter how if it is about recognized brands or icon products. Hazards a...

  13. Processing of LEU targets for 99Mo production--testing and modification of the Cintichem process

    International Nuclear Information System (INIS)

    Wu, D.; Landsberger, S.; Buchholz, B.

    1995-09-01

    Recent experimental results on testing and modification of the Cintichem process to allow substitution of low enriched uranium (LEU) for high enriched uranium (HEU) targets are presented in this report. The main focus is on 99 Mo recovery and purification by its precipitation with α-benzoin oxime. Parameters that were studied include concentrations of nitric and sulfuric acids, partial neutralization of the acids, molybdenum and uranium concentrations, and the ratio of α-benzoin oxime to molybdenum. Decontamination factors for uranium, neptunium, and various fission products were measured. Experiments with tracer levels of irradiated LEU were conducted for testing the 99 Mo recovery and purification during each step of the Cintichem process. Improving the process with additional processing steps was also attempted. The results indicate that the conversion of molybdenum chemical processing from HEU to LEU targets is possible

  14. Public Involvement in Decisions to Avoid Costly Consequences Later

    International Nuclear Information System (INIS)

    Treichel, Judy

    2006-01-01

    There should be an agreement of goals in any project that could produce harm. Why are we developing this technology? Who benefits and who pays? What would a 'cleanup' entail? There must be consideration of alternatives with a focus on reducing harm rather than just meeting allowable limits or promising that they will be met in the future. When alternatives are weighed, the burden should be on the proponent of the activity to provide truthful information to the public and provide access and resources necessary for participation. There must be a formal, legal obligation or duty to consider science as well as non-scientific information. It should not be up to those harmed to prove the damage and force the responsible parties to make retribution. It should be the burden of the proponents to measure potential risks, and prove that the benefits to everyone outweigh the risks to everyone. The role of government in decision making should also be redefined. The considerations now seem to be limited to whether or not an action is 'legal' or if it is 'safe'. There should also be a determination that it is 'necessary'. That may seem to be a very difficult question but put simply, if there are alternatives then a thing is not 'necessary'. Governmental decision makers would say: 'We acknowledge that our world will never be free from risk. However, any risk that is unnecessary or not freely chosen is not acceptable'. There must be a move away from situations where prior, important decisions resulted in winners and losers; wealthy beneficiaries and underprivileged victims. There must be recognition that decision making needs to be inclusive, extensive and democratic and that the end products and final results are necessary and worthwhile before projects begin. They must be visible, accessible, and must reflect the cost of doing business which includes taking the time, finding the information and involving the people who will work together to make sure that harm is avoided and

  15. ITI-signals and prelimbic cortex facilitate avoidance acquisition and reduce avoidance latencies, respectively, in male WKY rats

    Directory of Open Access Journals (Sweden)

    Kevin D Beck

    2014-11-01

    Full Text Available As a model of anxiety disorder vulnerability, male Wistar-Kyoto (WKY rats acquire lever-press avoidance behavior more readily than outbred Sprague Dawley rats, and their acquisition is enhanced by the presence of a discrete signal presented during the inter-trial intervals (ITIs, suggesting it is perceived as a safety signal. A series of experiments were conducted to determine if this is the case. Additional experiments investigated if the avoidance facilitation relies upon processing through medial prefrontal cortex (mPFC. The results suggest that the ITI-signal facilitates acquisition during the early stages of the avoidance acquisition process, when the rats are initially acquiring escape behavior and then transitioning to avoidance behavior. Post-avoidance introduction of the visual ITI-signal into other associative learning tasks failed to confirm that the visual stimulus had acquired the properties of a conditioned inhibitor. Shortening the signal from the entirety of the 3 min ITI to only the first 5 s of the 3 min ITI slowed acquisition during the first 4 sessions, suggesting the flashing light is not functioning as a feedback signal. The prelimbic (PL cortex showed greater activation during the period of training when the transition from escape responding to avoidance responding occurs. Only combined PL+infralimbic cortex lesions modestly slowed avoidance acquisition, but PL cortex lesions slowed avoidance response latencies. Thus, the flashing light ITI-signal is not likely perceived as a safety signal nor is it serving as a feedback signal. The functional role of the PL cortex appears to be to increase the drive towards responding to the threat of the warning signal. Hence, avoidance susceptibility displayed by male WKY rats may be driven, in part, both by external stimuli (ITI signal as well as by enhanced threat recognition to the warning signal via the PL cortex.

  16. Blocking of conditioned taste avoidance induced by wheel running.

    Science.gov (United States)

    Pierce, W David; Heth, C Donald

    2010-01-01

    In Experiment 1, compared to non-reinforced presentation of a food stimulus (A-->no US), the association of a food stimulus with wheel running (A-->US) blocked subsequent avoidance of a distinctive flavor (X), when both the food and flavor were followed by wheel running (AX-->US). Experiment 2 replicated and extended the blocking effect, demonstrating that the amount of avoidance of X after AX-->wheel training depended on the correlation between A-alone trials and wheel running-the predictiveness of the A stimulus. The present study is the first to demonstrate associative blocking of conditioned taste avoidance (CTA) induced by wheel running and strongly implicates associative learning as the basis for this kind of avoidance. 2009 Elsevier B.V. All rights reserved.

  17. Avoided emissions. Enterprises assess their solutions for the climate

    International Nuclear Information System (INIS)

    Colas, Julien

    2017-09-01

    In its first part, this publication gives an overview of the issues of avoided emissions: reasons for their calculation, risks to be understood and anticipated, relationships between avoided emissions and enterprises, avoided emissions in the enterprise climate strategy, and available calculation methods. The second part describes the methodology and process of calculation of avoided emissions: project initiation, method selection, reference solution selection, scenario elaboration, definition of the scope of calculation, taking the whole value chain into account, result consolidation, communication. A synthesis of recommendations is provided. Within the text, this publication proposes presentations of actions undertaken by several French companies or French subsidiaries like Air France, BASF, EDF, Michelin, Paprec, RTE, Saint-Gobain, SNCF, Suez, Total, Veolia, and others

  18. The Color Red Supports Avoidance Reactions to Unhealthy Food.

    Science.gov (United States)

    Rohr, Michaela; Kamm, Friederike; Koenigstorfer, Joerg; Groeppel-Klein, Andrea; Wentura, Dirk

    2015-01-01

    Empirical evidence suggests that the color red acts like an implicit avoidance cue in food contexts. Thus specific colors seem to guide the implicit evaluation of food items. We built upon this research by investigating the implicit meaning of color (red vs. green) in an approach-avoidance task with healthy and unhealthy food items. Thus, we examined the joint evaluative effects of color and food: Participants had to categorize food items by approach-avoidance reactions, according to their healthfulness. Items were surrounded by task-irrelevant red or green circles. We found that the implicit meaning of the traffic light colors influenced participants' reactions to the food items. The color red (compared to green) facilitated automatic avoidance reactions to unhealthy foods. By contrast, approach behavior toward healthy food items was not moderated by color. Our findings suggest that traffic light colors can act as implicit cues that guide automatic behavioral reactions to food.

  19. Obstacle Avoidance for Unmanned Undersea Vehicle in Unknown Unstructured Environment

    Directory of Open Access Journals (Sweden)

    Zheping Yan

    2013-01-01

    Full Text Available To avoid obstacle in the unknown environment for unmanned undersea vehicle (UUV, an obstacle avoiding system based on improved vector field histogram (VFH is designed. Forward looking sonar is used to detect the environment, and the divisional sonar modal is applied to deal with the measure uncertainty. To adapt to the VFH, rolling occupancy grids are used for the map building, and high accuracy details of local environment are obtained. The threshold is adaptively adjusted by the statistic of obstacles to solve the problem that VFH is sensitive to threshold. To improve the environment adaptability, the hybrid-behaviors strategy is proposed, which selects the optimal avoidance command according to the motion status and environment character. The simulation shows that UUV could avoid the obstacles fast and escape from the U shape obstacles.

  20. Avoided losses on LV networks as a result of microgeneration

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Paulo Moises [Escola Superior Tecnologia Viseu, Instituto Politecnico Viseu, Campus Politecnico Repeses, 3504-510 Viseu (Portugal); Matos, Manuel A. [INESC Porto, Faculdade de Engenharia da Universidade do Porto, Porto (Portugal)

    2009-04-15

    In the scope of the discussions about microgeneration (and microgrids), the avoided electrical losses are often pointed out as an important value to be credited to those entities. Therefore, methods to assess the impact of microgeneration on losses must be developed in order to support the definition of a suitable regulatory framework for the economic integration of microgeneration on distribution networks. This paper presents an analytical method to quantify the value of avoided losses that microgeneration may produce on LV networks. Intervals of expected avoided losses are used to account for the variation of avoided losses due to the number, size and location of microgenerators, as well as for the kind of load distribution on LV networks. (author)

  1. Knowing and avoiding plagiarism during scientific writing | Mohan ...

    African Journals Online (AJOL)

    Knowing and avoiding plagiarism during scientific writing. ... from the original source without giving adequate credit to the main source. When we search databases like PubMed/MedLine there is a lot of information regarding plagiarism.

  2. AVOIDING RISK IN WORKING CAPITAL CREDIT DISTRIBUTION IN INDONESIA

    Directory of Open Access Journals (Sweden)

    Aloysius Deno Hervino

    2011-09-01

    Full Text Available This research analyzes risk avoidance behaviour of banking institutions in distributing working capital loan in Indonesia. Using Autoregressive Distributed Lag Error Correction Model, this paper uncovers three findings. First, in the short run, risk avoidance in working capital loan distribution depends on inter-call banking money market and Sertifikat Bank Indonesia. Second, following banking regulation after 1997 crisis, banks have become more careful in distributing credits, with SBI as a substitution instrument and inter-call banking money market as a complement instrument to spread the risk. Third, all explanatory variables take an average of 6 days or 1 week to influence bank’s risk avoidance behaviour.Keywords:     Risk avoidance, working capital distribution, banking institutions JEL classification numbers: C32, C52, D81, E51

  3. Potential Nematode Alarm Pheromone Induces Acute Avoidance in Caenorhabditis elegans.

    Science.gov (United States)

    Zhou, Ying; Loeza-Cabrera, Mario; Liu, Zheng; Aleman-Meza, Boanerges; Nguyen, Julie K; Jung, Sang-Kyu; Choi, Yuna; Shou, Qingyao; Butcher, Rebecca A; Zhong, Weiwei

    2017-07-01

    It is crucial for animal survival to detect dangers such as predators. A good indicator of dangers is injury of conspecifics. Here we show that fluids released from injured conspecifics invoke acute avoidance in both free-living and parasitic nematodes. Caenorhabditis elegans avoids extracts from closely related nematode species but not fruit fly larvae. The worm extracts have no impact on animal lifespan, suggesting that the worm extract may function as an alarm instead of inflicting physical harm. Avoidance of the worm extract requires the function of a cGMP signaling pathway that includes the cGMP-gated channel TAX-2/TAX-4 in the amphid sensory neurons ASI and ASK. Genetic evidence indicates that the avoidance behavior is modulated by the neurotransmitters GABA and serotonin, two common targets of anxiolytic drugs. Together, these data support a model that nematodes use a nematode-specific alarm pheromone to detect conspecific injury. Copyright © 2017 by the Genetics Society of America.

  4. Parents: Avoid Kids Foot Problems with the Right Shoes

    Science.gov (United States)

    ... Print | Share Avoid Kids Foot Problems with the Right Shoes Before you head to the store to ... College of Foot and Ankle Surgeons (ACFAS), All Rights Reserved. Privacy Statement | Disclaimer | Terms and Conditions | Site ...

  5. Fighter/Attack Automatic Collision Avoidance Systems Business Case

    National Research Council Canada - National Science Library

    Mapes, Peter B

    2006-01-01

    .... This study concludes that implementation of Automatic Collision Avoidance Systems (Auto-CAS) in F-16, F/A-18, F/A-22, and F-35 aircraft would save aircrew lives and preserve, and enhance combat capability.

  6. Tax avoidance with cross-border hybrid instruments

    DEFF Research Database (Denmark)

    Johannesen, Niels

    2014-01-01

    in the other country with a cross-border hybrid instrument. We then investigate why countries tend to allow the use of hybrid instruments for tax avoidance and show that even if effective anti-avoidance rules are available, there exists a global policy equilibrium in which no country uses such rules......The rules demarcating debt and equity for tax purposes differ between countries, hence the possibility that a hybrid financial instrument is treated as equity in one country and debt in another. This may create a scope for tax avoidance by allowing firms that invest in foreign countries to combine...... tax deductible interest expenses in the host country and tax favored dividend income in the home country. In this paper, we first develop a formal model of hybrid instruments and show that, for a given pair of countries, firms in at least one country and sometimes in both can avoid taxes on investment...

  7. Diabetes Care: 10 Ways to Avoid Diabetes Complications

    Science.gov (United States)

    Diabetes care: 10 ways to avoid complications Diabetes care is a lifelong responsibility. Consider 10 strategies to prevent diabetes complications. By Mayo Clinic Staff Diabetes is a serious disease. Following ...

  8. Plans and Measures for Avoiding Casting-Air-Pollution

    Institute of Scientific and Technical Information of China (English)

    ZHOU Jian

    2003-01-01

    This article presents plans of preventing casting-air-pollution in practice, and some avoiding methods in detail. In modern times, environment protection is looked high upon day by day; green-casting thus becomes more and more important.

  9. Transfer pricing as tax avoidance under different legislative schemes

    OpenAIRE

    Holzmann, Carolin Maria

    2016-01-01

    This paper investigates transfer pricing as tax avoidance before and after reforms of anti-avoidance legislation. The reforms introduced and tightened obligatory documentation requirements for transfer prices to enforce that multinational enterprises (MNEs) set internal transfer prices at an arm’s-length. Linking data from the Microdatabase Statistics on International Trade in Services that comprehends prices of MNEs’ international service transactions to the Microdatabase Direct Investment, ...

  10. Impact of Tactical and Strategic Weather Avoidance on Separation Assurance

    Science.gov (United States)

    Refai, Mohamad S.; Windhorst, Robert

    2011-01-01

    The ability to keep flights away from weather hazards while maintaining aircraft-to-aircraft separation is critically important. The Advanced Airspace Concept is an automation concept that implements a ground-based strategic conflict resolution algorithm for management of aircraft separation. The impact of dynamic and uncertain weather avoidance on this concept is investigated. A strategic weather rerouting system is integrated with the Advanced Airspace Concept, which also provides a tactical weather avoidance algorithm, in a fast time simulation of the Air Transportation System. Strategic weather rerouting is used to plan routes around weather in the 20 minute to two-hour time horizon. To address forecast uncertainty, flight routes are revised at 15 minute intervals. Tactical weather avoidance is used for short term trajectory adjustments (30 minute planning horizon) that are updated every minute to address any weather conflicts (instances where aircraft are predicted to pass through weather cells) that are left unresolved by strategic weather rerouting. The fast time simulation is used to assess the impact of tactical weather avoidance on the performance of automated conflict resolution as well as the impact of strategic weather rerouting on both conflict resolution and tactical weather avoidance. The results demonstrate that both tactical weather avoidance and strategic weather rerouting increase the algorithm complexity required to find aircraft conflict resolutions. Results also demonstrate that tactical weather avoidance is prone to higher airborne delay than strategic weather rerouting. Adding strategic weather rerouting to tactical weather avoidance reduces total airborne delays for the reported scenario by 18% and reduces the number of remaining weather violations by 13%. Finally, two features are identified that have proven important for strategic weather rerouting to realize these benefits; namely, the ability to revise reroutes and the use of maneuvers

  11. Karakteristik Eksekutif Terhadap Tax Avoidance Dengan Leverage Sebagai Variabel Intervening

    OpenAIRE

    Carolina, Verani; Natalia, Maria; Debbianita, Debbianita

    2014-01-01

    This research aimed to examine the influence of the executive characteristic on corporate tax avoidance. Risktaker’s executive tended to be more courageous and aggressive in taking decision related to the tax. On thecontrary, the risk averse executive tended to be carefully (Low, 2006). This research used leverage as interveningvariable. Therefore, there was an assumption that the executive characteristic determined the corporateleverage which then influenced their tax avoidance in the compan...

  12. Different Tax Systems among Nations and International Tax Avoidance

    OpenAIRE

    栗原, 克文

    2008-01-01

    As economic globalization proceeds, tax policies of one nation influence others more and greater pressures are imposed on tax systems and tax administrations.The possibility of tax avoidance will expand if cross-border transactions are abused.Specifically, tax system differentials among countries increase the opportunity for tax avoidance.Under some tax avoidance schemes, foreign entities which have no or little economic substance are used to create artificial losses, so that they can minimiz...

  13. BDNF, impulsiveness and avoidant focused coping in suicide attempters

    OpenAIRE

    AMBRUS, LIVIA

    2016-01-01

    Brain-derived neurotrophic factor (BDNF) is an important protein for neuroplasticity and neurogenesis. In this thesis the role of BDNF, in suicidal behaviour was investigated with focus on possible risk factors for suicidal behaviour such as avoidant focused coping, dysfuntional personality traits like impulsiveness and hyperactivity of the Hypothalamic-Pituitary-Adrenal (HPA) axis.Paper I: The association between avoidant focused coping and the BDNF Val66Met gene polymorphism in two differen...

  14. Collision Avoidance Functional Requirements for Step 1. Revision 6

    Science.gov (United States)

    2006-01-01

    This Functional Requirements Document (FRD) describes the flow of requirements from the high level operational objectives down to the functional requirements specific to cooperative collision avoidance for high altitude, long endurance unmanned aircraft systems. These are further decomposed into performance and safety guidelines that are backed up by analysis or references to various documents or research findings. The FRD should be considered when establishing future policies, procedures, and standards pertaining to cooperative collision avoidance.

  15. Automatic lateral emergency collision avoidance for a passenger car

    OpenAIRE

    Bevan, G.; Gollee, H.; O'Reilly, J.

    2007-01-01

    Longitudinal collision avoidance controllers are of limited benefit for preventing head-on collisions between road vehicles travelling at high speed or for preventing rear end collisions when there is insufficient separation between the vehicles. In these circumstances, aggressive lateral vehicle manoeuvres are more appropriate. This paper develops a controller architecture to perform an emergency lateral collision avoidance manoeuvre. Simulation results indicate significant improvements in c...

  16. Artificial potential functions for highway driving with collision avoidance

    OpenAIRE

    Wolf , Michael T.; Burdick, Joel W.

    2008-01-01

    We present a set of potential function components to assist an automated or semi-automated vehicle in navigating a multi-lane, populated highway. The resulting potential field is constructed as a superposition of disparate functions for lane- keeping, road-staying, speed preference, and vehicle avoidance and passing. The construction of the vehicle avoidance potential is of primary importance, incorporating the structure and protocol of laned highway driving. Particularly, the shape and dimen...

  17. Which E-Lifestyle Avoids Internet Advertising More?

    OpenAIRE

    Amir Abedini Koshksaray; Kambiz Heidarzadeh Hanzaee

    2014-01-01

    This study aimed at finding out which e-lifestyles avoid internet advertising more. To this aim, a survey was conducted on 412 students working with internet. Structural Equation Modeling approach was used for estimating the validity of research constructs and multiple regression was utilized for hypothesis testing. According to the findings, individuals with interest-driven e-lifestyle avoid from internet advertising more than others. Novelty-driven, importance-driven, sociability-driven, ne...

  18. Self-protection Method for Flying Robots to Avoid Collision

    OpenAIRE

    Guosheng Wu; Luning Wang; Changyuan Fan; Xi Zhu

    2008-01-01

    This paper provides a new approach to solve the motion planning problems of flying robots in uncertain 3D dynamic environments. The robots controlled by this method can adaptively choose the fast way to avoid collision without information about the shapes and trajectories of obstacles. Based on sphere coordinates the new method accomplishes collision avoidance of flying robots without any other auxiliary positioning systems. The Self-protection System gives robots self-protection abilities to...

  19. Preparation of neptunium and plutonium tracers in nuclear reactions of sup 2 sup 3 sup 6 U with (21-60)MeV sup 3 He ions

    CERN Document Server

    Aaltonen, J; Trzaska, V; Gromova, E A; Yakovlev, V A

    2001-01-01

    Preparation of sup 2 sup 3 sup 6 Pu, sup 2 sup 3 sup 7 Pu and sup 2 sup 3 sup 5 Np by reactions sup 2 sup 3 sup 6 U( sup 3 He, t beta sup -) sup 2 sup 3 sup 6 Pu, sup 2 sup 3 sup 6 U( sup 3 He, 2n) sup 2 sup 3 sup 7 Pu and sup 2 sup 3 sup 6 U( sup 3 He, p3n) sup 2 sup 3 sup 5 Np in sup 3 He ion beams, their energy 43 and 60 MeV, in the K-130 cyclotron at Yuvyaskyul University (Finland) was studied. Cross sections of the reactions were determined. Yield curves for thick targets were calculated. The results are discussed and compared with previously obtained data on other reactions giving rise to formation of the same products. Methods of radiochemical separation of the products and sample preparation for alpha- and gamma-spectrometry are described

  20. Multi-actuators vehicle collision avoidance system - Experimental validation

    Science.gov (United States)

    Hamid, Umar Zakir Abdul; Zakuan, Fakhrul Razi Ahmad; Akmal Zulkepli, Khairul; Zulfaqar Azmi, Muhammad; Zamzuri, Hairi; Rahman, Mohd Azizi Abdul; Aizzat Zakaria, Muhammad

    2018-04-01

    The Insurance Institute for Highway Safety (IIHS) of the United States of America in their reports has mentioned that a significant amount of the road mishaps would be preventable if more automated active safety applications are adopted into the vehicle. This includes the incorporation of collision avoidance system. The autonomous intervention by the active steering and braking systems in the hazardous scenario can aid the driver in mitigating the collisions. In this work, a real-time platform of a multi-actuators vehicle collision avoidance system is developed. It is a continuous research scheme to develop a fully autonomous vehicle in Malaysia. The vehicle is a modular platform which can be utilized for different research purposes and is denominated as Intelligent Drive Project (iDrive). The vehicle collision avoidance proposed design is validated in a controlled environment, where the coupled longitudinal and lateral motion control system is expected to provide desired braking and steering actuation in the occurrence of a frontal static obstacle. Results indicate the ability of the platform to yield multi-actuators collision avoidance navigation in the hazardous scenario, thus avoiding the obstacle. The findings of this work are beneficial for the development of a more complex and nonlinear real-time collision avoidance work in the future.