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Sample records for boron bromides

  1. Boron-doped diamond anodic oxidation of ethidium bromide: Process optimization by response surface methodology

    International Nuclear Information System (INIS)

    Highlights: ► Boron-doped diamond was used to degrade ethidium bromide. ► The process was optimized by a central composite rotatable design coupled with response surface methodology. ► Applied current is proved to be the most significant variable. ► A possible reaction sequence involving all the detected byproducts was proposed. - Abstract: The degradation of ethidium bromide (EtBr), a DNA intercalating pollutant, had been studied by anodic oxidation on boron-doped diamond (BDD) electrode under galvanostatic conditions. A central composite rotatable design coupled with response surface methodology was implemented to optimize the various operating parameters involved, among initial pH, flow rate, applied current and supporting electrolyte concentration, on the treatment efficiency; the latter was assessed in terms of color removal, COD removal, specific energy consumption and general current efficiency. Of the four parameters involved, applied current had a considerable effect on all the response factors. Optimum EtBr degradation was achieved by applying a current of 0.90 A, 9.0 mM Na2SO4, flow rate of 400 ml min−1 and pH 6.2 at 60 min of electrolysis, being reduced color by 80.2% and COD by 29.7%, with an energy consumption of 398.32 kW h (kg COD)−1 and a general current efficiency of 10.1%. Under these optimized conditions, EtBr decays followed pseudo first-order kinetics. Moreover, HPLC analysis of the BDD-treated solution allowed the detection of a number of reaction intermediates, and a possible reaction sequence involving all the detected byproducts was proposed for the electrochemical oxidation of EtBr on BDD anode.

  2. Boron

    International Nuclear Information System (INIS)

    The trace element boron (B) is of interest in reclamation situations for several reasons. It plays an essential through largely unidentified role in the growth of higher plants. In argronomic situations B deficiencies are common, and deficiencies in reclamation situations have been suggested but not documented. Among micronutrients, B is unique because the range from deficient concentrations to toxic concentrations either in the soil solution or in plant tissue is narrower than for any other micronutrient. In reclamation situations excessive amounts of B can occur in the soil or in near-surface mining wastes and thus interfere with reclamation objectives, especially in arid and semiarid regions. Also, B is mobile and appears subject to both upward transport (and possible contamination of overlying material) and downward transport (and possible contamination of surface water and groundwater)

  3. Methylnaltrexone bromide methanol monosolvate

    Directory of Open Access Journals (Sweden)

    Xinbo Zhou

    2012-03-01

    Full Text Available In the title compound [systematic name: (4R,4aS,7aR,12bS-3-cyclopropylmethyl-4a,9-hydroxy-7-oxo-2,3,4,4a,5,6,7,7a-octahydro-1H-4,12-methanobenzofuro[3,2-e]isoquinolin-3-ium bromide methanol monosolvate], C21H26NO4+·Br−·CH3OH, two of the three six-membered rings adopt chair conformations while the third, which contains a C=C double bond, adopts an approximate half-boat conformation. The 2,3-dihydrofuran ring adopts an envelope conformation. In the crystal, the components are linked by O—H...O and O—H...Br hydrogen bonds. The absolute stereochemistry was inferred from one of the starting materials.

  4. Electroextraction of boron from boron carbide scrap

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Ashish [Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam – 603102 (India); Anthonysamy, S., E-mail: sas@igcar.gov.in [Chemistry Group, Indira Gandhi Centre for Atomic Research, Kalpakkam – 603102 (India); Ghosh, C. [Physical Metallurgy Group, Indira Gandhi Centre for Atomic Research, Kalpakkam – 603102 (India); Ravindran, T.R. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam – 603102 (India); Divakar, R.; Mohandas, E. [Physical Metallurgy Group, Indira Gandhi Centre for Atomic Research, Kalpakkam – 603102 (India)

    2013-10-15

    Studies were carried out to extract elemental boron from boron carbide scrap. The physicochemical nature of boron obtained through this process was examined by characterizing its chemical purity, specific surface area, size distribution of particles and X-ray crystallite size. The microstructural characteristics of the extracted boron powder were analyzed by using scanning electron microscopy and transmission electron microscopy. Raman spectroscopic examination of boron powder was also carried out to determine its crystalline form. Oxygen and carbon were found to be the major impurities in boron. Boron powder of purity ∼ 92 wt. % could be produced by the electroextraction process developed in this study. Optimized method could be used for the recovery of enriched boron ({sup 10}B > 20 at. %) from boron carbide scrap generated during the production of boron carbide. - Highlights: • Recovery of {sup 10}B from nuclear grade boron carbide scrap • Development of process flow sheet • Physicochemical characterization of electroextracted boron • Microscopic examination of electroextracted boron.

  5. Electroextraction of boron from boron carbide scrap

    International Nuclear Information System (INIS)

    Studies were carried out to extract elemental boron from boron carbide scrap. The physicochemical nature of boron obtained through this process was examined by characterizing its chemical purity, specific surface area, size distribution of particles and X-ray crystallite size. The microstructural characteristics of the extracted boron powder were analyzed by using scanning electron microscopy and transmission electron microscopy. Raman spectroscopic examination of boron powder was also carried out to determine its crystalline form. Oxygen and carbon were found to be the major impurities in boron. Boron powder of purity ∼ 92 wt. % could be produced by the electroextraction process developed in this study. Optimized method could be used for the recovery of enriched boron (10B > 20 at. %) from boron carbide scrap generated during the production of boron carbide. - Highlights: • Recovery of 10B from nuclear grade boron carbide scrap • Development of process flow sheet • Physicochemical characterization of electroextracted boron • Microscopic examination of electroextracted boron

  6. Simultaneous determination of boron-10 and boron-11 under proton bombardment

    International Nuclear Information System (INIS)

    The isotopic analysis of boron gained importance with increased use of boron-10 in nuclear technology. Former techniques for determining the stable boron isotope either were limited to the determination of a single isotope or required tedious experimental prodecure. The use of proton induced reactions was therefore investigated as an alternative method for the simultaneous analysis of both stable isotopes of boron through a relatively simple experimental procedure. Aqueous solutions of natural boric acid (19,78 at. % 10B) and enriched boric acid (92,41 at. % 10B) were mixed and evaporated to dryness in order to obtain samples in which the isotopic concentration of boron was known. Thin targets were produced by evaporating boron oxide, converted by heat from the boric acid mixture, onto tantalum backing material. Standard samples with known contents of boron oxide were prepared by dry mixing standard reference boron-containing glass powers in a ball mill. Thick targets containing boron of different isotopic compositions were prepared in matrices of potassium bromide and of ion-exchange resins by mixing the matrix with aqueous solutions of boric acid and of sodium carbonate by fusion with boric oxide. The most intense prompt gamma-rays emitted from boron isotopes under irradiation with protons up to 4,5 MeV were the 428-KeV 10B α(1,0), 718-KeV 10B p(1,0) and the 2124-KeV 11B p(1,0) gamma-rays. Excitation functions for the production of each of these were measured using both thick and thin targets

  7. Determination of boron content in boron carbide, boron nitride and amorphous boron

    International Nuclear Information System (INIS)

    In the present article an analyzing method of determination of boron content in boron carbide, boron nitride and amorphous boron described. Examined samples were digested with potassium hydroxide and potassium nitrate in nickel crucible and the boron contents determined subsequently by an alcalimetric titration of boric acid in presence of mannite resp. sorbite. (author)

  8. Elementary boron and metal-boron compounds

    International Nuclear Information System (INIS)

    Elementary boron is of interest for its peculiar and difficult bonding behaviour in solids. Due to its high oxygen affinity we find no elementary boron in nature. For the same reason it is difficult to isolate pure, elementary boron, and much confusion about 'boron crystals' has been the result of more than 100 years of research. The polymorphic forms of elementary boron and its closely related higher carbides and higher metal borides as well as the simple metal borides, B3C and BN are reported. The quantum-mechanical background responsible for structure and stoichiometry of these crystals is given. (orig.)

  9. Conversion of Alcohols to Bromides by Trimethylsilane and lithium Bromide in Acetone

    Institute of Scientific and Technical Information of China (English)

    Wei Feng; Zhang Xiao-xia; Zhang Qing; Wang Ji-yu; Chen Dai-mo

    2004-01-01

    Conversion of alcohols to alkyl bromides is one of the most frequently used functional group transformation reactions. Phosphorus tribromide is one of the most popular classical reagents.Triphenylphosphine has been used in combination with bromine,carbon tetrabromide,N-halo imides and other bromide compounds as a mild reagents for the preparation of alkyl bromides.More reacently, halotrimethylsilanes were found to be useful for halogenation of alcohols. George A.Olah successfully converted alcohols to bromides with chlorotrimethylsilane/lithium bromide in acetonitrile. But in our research, we found that we got no bromides but methylation products when we planed to convered our substances to bromides according to Gerge's method. We did some experiments, and we found that when the substituent group in the 2-N was donor group,we got the methylation products,but when it was acceptor group,the bromide could be got.(Scheme 1).Then we did some experiments with several other solvents, we found excitedly that when the solvent was acetone ,the bromides could be got even the substituent group was donor.(Scheme 2).When we changed the substances to normal alcohols ,such as ethyl alcohol,benzyl alcohol,isopropyl alcohol and 3,4-dimethoxy benzyl alcohol,we also got the bromides.In conclusion, we found a simple method to convert alcohols to bromides with trimethylsilane/li thium bromide in acetone,which was better than Geroge's method.

  10. Sputtering behavior of boron and boron carbide

    International Nuclear Information System (INIS)

    Sputtering yields of boron were measured with D+ and B+ ions for normal and oblique angles of incidence. Self-sputtering data of boron carbide were simulated in the experiment by using Ne+ ions. The energies of the impinging ions were between 20 eV and 10 keV. The measured data are compared with computer simulated values calculated with the TRIMSP program. The boron data for normal ion impact are higher than the calculated values, whereas those for oblique ion incidence are smaller than the calculation predicts. This discrepancy is explained by the surface roughness and supported by SEM micrographs. The comparison of the boron carbide data with TRIMSP calculations shows much better agreement than the boron data. In this case the target surface was much smoother. (orig.)

  11. Boron nitride converted carbon fiber

    Energy Technology Data Exchange (ETDEWEB)

    Rousseas, Michael; Mickelson, William; Zettl, Alexander K.

    2016-04-05

    This disclosure provides systems, methods, and apparatus related to boron nitride converted carbon fiber. In one aspect, a method may include the operations of providing boron oxide and carbon fiber, heating the boron oxide to melt the boron oxide and heating the carbon fiber, mixing a nitrogen-containing gas with boron oxide vapor from molten boron oxide, and converting at least a portion of the carbon fiber to boron nitride.

  12. Mass spectrometric determination of boron isotope in boron carbide

    International Nuclear Information System (INIS)

    Boron isotopes in boron carbide are measured by thermionic ionization mass spectrometry with no prior chemical separation. Boron is converted to sodium borate by fusion of the boron carbide with sodium hydroxide (or sodium carbonate) directly on the rhenium filament. The boron isotopic ratios are measured by using the Na2BO2+ ion

  13. 49 CFR 173.193 - Bromoacetone, methyl bromide, chloropicrin and methyl bromide or methyl chloride mixtures, etc.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Bromoacetone, methyl bromide, chloropicrin and methyl bromide or methyl chloride mixtures, etc. 173.193 Section 173.193 Transportation Other Regulations... bromide, chloropicrin and methyl bromide or methyl chloride mixtures, etc. (a) Bromoacetone must...

  14. The metabolism of valethamate bromide, 1

    International Nuclear Information System (INIS)

    Valethamate bromide is widely used as a potent antispasmodic and antiulcerative agent. Studies were carried out to investigate the absorption, excretion and distribution of valethamate bromide in rats and men. When rats were given valethamate bromide-14C by subcutaneous injection, maximum blood concentration was reached at 1 to 2 hr after injection. The radioactivity was relatively highly distributed in kidney, liver, intestine and stomach. After subcutaneous injection, 57% of the administered dose was excreted in urine and 30% in feces within 48 hr. In the peroral administration, the transition of blood concentration levels did not present its peak clearly. Relatively high levels of radioactivity were present in stomach, intestine, kidney and liver. In the studies of biliary excretion used with unlabeled valethamate bromide, only when rats were administered by subcutaneous injection, 0.1 to 0.4% of the injected dose was recovered from the basic fraction of bile in 6 hr after injection. Our study revealed that there was difference between the urinary excretion rate of labeled and unlabeled valethamate bromide. And it was found that the transition of distributed amount into the tissues, which were abundant with lipid (as brain, fat and genitalia) and had the inclination to be distributed much in the second stage than in the first stage after administration, was not in proportion as blood concentrations. Consequently, it seems that valethamate bromide is partly metabolized to lipid-soluble compounds in body. When volunteers were administered Resitan by mouth, 2.7 to 5.5% of the dose was excreted in urine within 48 hrs. However, 42.5 to 47.5% of the administered dose was excreted in urine within 24 hr after intramuscular administration. Valethamate bromide was rapidly and virtually completely absorbed in both rats (s.c.) and men (i.m.), whereas 4 to 5% and 2.7 to 5.5% of the administered dose was excreted in rats and men after peroral administration. (author)

  15. Modeling and analysis of calcium bromide hydrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Lottes, Steven A.; Lyczkowski, Robert W.; Panchal, Chandrakant B.; Doctor, Richard D. [Energy Systems Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439 (United States)

    2009-05-15

    The main focus of this paper is the modeling, simulation, and analysis of the calcium bromide hydrolysis reactor stage in the calcium-bromine thermochemical water-splitting cycle for nuclear hydrogen production. One reactor concept is to use a spray of calcium bromide into steam, in which the heat of fusion supplies the heat of reaction. Droplet models were built up in a series of steps incorporating various physical phenomena, including droplet flow, heat transfer, phase change, and reaction, separately. Given the large heat reservoir contained in a pool of molten calcium bromide that allows bubbles to rise easily, using a bubble column reactor for the hydrolysis appears to be a feasible and promising alternative to the spray reactor concept. The two limiting cases of bubble geometry, spherical and spherical-cap, are considered in the modeling. Results for both droplet and bubble modeling with COMSOL MULTIPHYSICS trademark are presented, with recommendations for the path forward. (author)

  16. Methyl bromide residues in fumigated cocoa beans with particular reference to inorganic bromide

    International Nuclear Information System (INIS)

    Inorganic bromide residues and 14C-labelled methylated products (expressed as CH3Br equivalent) in cocoa beans fumigated with [14C]-methyl bromide have been determined by radiometric and chemical methods. Determination of 14C by direct combustion in an oxygen chamber followed by liquid scintillation counting confirmed previous findings with respect to the magnitude, distribution and chemical nature of the residues. Although recovery of added bromide was good, the values of total bromide obtained by the chemical method were only half of those estimated from the total residual 14C-activity. This is attributed to loss of organic (presumably, protein-bound) bromide. In agreement with the total 14C-labelled residue contents, total bromide in shells was 20 times greater than that in nibs. The low levels of residues in the nib (12ppm as CH3Br equivalent, 10ppm Br) and the further reduction of organic residues by roasting suggest that no toxicological and nutritional hazards may be expected from fumigation of cocoa beans with methyl bromide. (author)

  17. Determination of boron and silicon in boron carbide

    International Nuclear Information System (INIS)

    A sodium carbonate fusion technique for the dissolution of boron carbide followed by the determination of boron by alkalimetric titration and silicon impurity by spectrophotometry is described. The elemental boron content in the commercially available boron carbide ranged from 77.2 to 77.60 % and the silicon in the range 1170 to 2500 ppm. (author)

  18. First boronization in KSTAR

    Energy Technology Data Exchange (ETDEWEB)

    Hong, S.H., E-mail: sukhhong@nfri.re.kr [National Fusion Research Institute, 113 Gwahangno, Yusung-Gu, Daejeon 305-333 (Korea, Republic of); Center for Edge Plasma Science (cEps), Hanyang University, Seoul 133-791 (Korea, Republic of); Lee, K.S.; Kim, K.M.; Kim, H.T.; Kim, G.P. [National Fusion Research Institute, 113 Gwahangno, Yusung-Gu, Daejeon 305-333 (Korea, Republic of); Sun, J.H.; Woo, H.J. [Department of Electrical Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Center for Edge Plasma Science (cEps), Hanyang University, Seoul 133-791 (Korea, Republic of); Park, J.M.; Kim, W.C.; Kim, H.K.; Park, K.R.; Yang, H.L.; Na, H.K. [National Fusion Research Institute, 113 Gwahangno, Yusung-Gu, Daejeon 305-333 (Korea, Republic of); Chung, K.S. [Department of Electrical Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Center for Edge Plasma Science (cEps), Hanyang University, Seoul 133-791 (Korea, Republic of)

    2010-11-15

    First boronization in KSTAR is reported. KSTAR boronization system is based on a carborane (C{sub 2}B{sub 10}H{sub 12}) injection system. The design, construction, and test of the system are accomplished and it is tested by using a small vacuum vessel before it is mounted to a KSTAR port. After the boronization in KSTAR, impurity levels are significantly reduced by factor of 3 (oxygen) and by 10 (carbon). Characteristics of a-C/B:H thin films deposited by carborane vapor are investigated. Re-condensation of carborane vapor during the test phase has been reported.

  19. Radiolytic reduction reaction of colloidal silver bromide solution

    International Nuclear Information System (INIS)

    The reduction reaction of colloidal silver bromide (AgBr3)2- in nitrous oxide gas saturated solution of some alcohols: methanol, ethanol, 2-propanol and 2-methyl-2-propanol by γ-irradiation was studied spectrophotometrically in order to elucidate the mechanism of the formation of colloidal silver bromide (AgBr3)3- at ambient temperature. The amount of colloidal silver bromide formed increases in the order: i-PrOH, EtOH, MeOH. In t-BuOH, colloidal silver bromide did not form. The relative reactivities of alcohols for colloidal silver bromide was also studied kinetically. (author)

  20. Boron in sillimanite.

    Science.gov (United States)

    Grew, E S; Hinthorne, J R

    1983-08-01

    Sillimanite in six granulite-facies, kornerupine-bearing rocks contains 0.035 to 0.43 percent B(2)O(3) and 0.02 to 0.23 percent MgO (by weight). Substitution of boron for silicon and magnesium for aluminum is coupled such that the ratio of magnesium to boron is about 0.5. Sillimanite incorporates more than 0.1 percent B(2)O(3) only at high temperatures in a boron-rich environment at very low partial pressures of water. In the amphibolite facies, the sillimanite boron contents are too low to appreciably affect the stability relations of sillimanite with kyanite and andalusite. PMID:17830955

  1. Boron nitride composites

    Energy Technology Data Exchange (ETDEWEB)

    Kuntz, Joshua D.; Ellsworth, German F.; Swenson, Fritz J.; Allen, Patrick G.

    2016-02-16

    According to one embodiment, a composite product includes hexagonal boron nitride (hBN), and a plurality of cubic boron nitride (cBN) particles, wherein the plurality of cBN particles are dispersed in a matrix of the hBN. According to another embodiment, a composite product includes a plurality of cBN particles, and one or more borate-containing binders.

  2. Methyl bromide residues in fumigated cocoa beans

    International Nuclear Information System (INIS)

    The 14C activity in unroasted [14C]-methyl bromide fumigated cocoa beans was used to study the fate and persistence of CH3Br in the stored beans. About 70% of the residues occurred in the shells. Unchanged CH3Br could not be detected, all the sorbed CH3Br having reacted with bean constituents apparently to form 14C-methylated derivatives and inorganic bromide. No 14C activity was found in the lipid fraction. Roasting decreased the bound (non-volatile) residues, with corresponding changes in the activities and amounts of free sugars, free and protein amino acids. Roasted nibs and shells showed a two-fold increase in the volatile fraction of the 14C residue. This fraction may be related to the volatile aroma compounds formed by Maillard-type reactions. (author)

  3. Removal of bromide and natural organic matter by anion exchange.

    Science.gov (United States)

    Hsu, Susan; Singer, Philip C

    2010-04-01

    Bromide removal by anion exchange was explored for various water qualities, process configurations, and resin characteristics. Simulated natural waters containing different amounts of natural organic matter (NOM), bicarbonate, chloride, and bromide were treated with a polyacrylate-based magnetic ion exchange (MIEX) resin on a batch basis to evaluate the effectiveness of the resin for removal of bromide. While bromide removal was achieved to some degree, alkalinity (bicarbonate), dissolved organic carbon (DOC), and chloride were shown to inhibit bromide removal in waters with bromide concentrations of 100 and 300 microg/L. Water was also treated using a two-stage batch MIEX process. Two-stage treatment resulted in only a slight improvement in bromide removal compared to single-stage treatment, presumably due to competition with the high concentration of chloride which is present along with bromide in natural waters. In view of the relatively poor bromide removal results for the MIEX resin, a limited set of experiments was performed using polystyrene resins. DOC and bromide removal were compared by treating model waters with MIEX and two polystyrene resins, Ionac A-641 and Amberlite IRA910. The two polystyrene resins were seen to be more effective for bromide removal, while the MIEX resin was more effective at removing DOC. PMID:20045170

  4. [Research advances in methyl bromide in the ocean].

    Science.gov (United States)

    Du, Hui-na; Xie, Wen-xia; Cui, Yu-qian; Chen, Jian-lei; Ye, Si-yuan

    2014-12-01

    Methyl bromide is an important atmospheric trace gas, which plays significant roles in the global warming and atmospheric chemistry. The ocean plays important and complex roles in the global biogeochemical cycles of methyl bromide, not only the source of atmospheric methyl bromide, but also the sink. Therefore, developing the chemical research of the soluble methyl bromide in the ocean, will not only have a certain guiding significance to the atmospheric ozone layer protection, but also provide a theoretical basis for estimating methyl bromide's contribution to the global environmental change on global scale. This paper reviewed the research advances on methyl bromide in the ocean, from the aspects of the biogeochemical cycle of methyl bromide in the ocean, the analysis and determination method, the concentration distribution, the sea-to-air flux and its sources and sinks in the atmosphere. Some deficiencies in the current studies were put forward, and the directions of the future studies were prospected. PMID:25876424

  5. Nitroethylation of vinyl triflates and bromides.

    Science.gov (United States)

    Padilla-Salinas, Rosaura; Walvoord, Ryan R; Tcyrulnikov, Sergei; Kozlowski, Marisa C

    2013-08-01

    A two-carbon homologation of vinyl triflates and bromides for the synthesis of homoallylic nitro products is described. This palladium-catalyzed double coupling of nitromethane exploits the anion stabilizing and leaving group properties of nitromethane, generating the homo allyl nitro products via a tandem cross-coupling/π-allylation sequence. The resultant process provides a mild and convenient entry to nitroethylated products, which are versatile precursors to β,γ-unsaturated carbonyls, homoallylic amines, and nitrile oxides. PMID:23885976

  6. Bromate oxidized from bromide during sonolytic ozonation.

    Science.gov (United States)

    Lu, Ning; Wu, Xue-Fei; Zhou, Ji-Zhi; Huang, Xin; Ding, Guo-Ji

    2015-01-01

    Sonolytic ozonation (US/O3) is an effective way to degrade many pollutants in drinking water as the elevated mass transfer rate of ozone gas and the enhanced forming of hydroxyl radicals (OH). This work investigated the formation of bromate (BrO3(-)) from bromide (Br(-)) in sonolytic ozonation. At neutral pH, the bromate conversion rate ([BrO3(-)]/[Br(-)]0) was increased to 60% by ultrasound at continuous ozone flow (0-0.2Lmin(-1)), much higher than that without ultrasound or without bubbling. This indicates that the promoting effect of sonolysis on BrO3(-) formation is mainly due to the sonolytic decomposition of ozone and the enhancement of gas-liquid transfer. The [BrO3(-)]/[Br(-)]0 was increased with increasing pH. In addition, the reduction of HOBr/OBr(-) with ultrasound demonstrates that bromate may be inhibited as the bromide was formed with the H2O2 generation under ultrasound. This suggests the competition between bromate and bromide during the US/O3 led to the inhibition of bromate formation at high ozone flow. Therefore, our result reveals that the bromate formation under ultrasound is improved remarkably in US/O3 in quick treatment with proper ozone flow (<0.2Lmin(-1)). PMID:24931426

  7. Boronated liposome development and evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Hawthorne, M.F. [Univ. of California, Los Angeles, CA (United States)

    1995-11-01

    The boronated liposome development and evaluation effort consists of two separate tasks. The first is the development of new boron compounds and the synthesis of known boron species with BNCT potential. These compounds are then encapsulated within liposomes for the second task, biodistribution testing in tumor-bearing mice, which examines the potential for the liposomes and their contents to concentrate boron in cancerous tissues.

  8. Magnetron sputter deposition of boron and boron carbide

    International Nuclear Information System (INIS)

    The fabrication of X-ray optical coatings with greater reflectivity required the development of sputter deposition processes for boron and boron carbide. The use of high density boron and boron carbide (B4C) and a vacuum-brazed target design was required to achieve the required sputter process stability and resistance to the thermal stress created by high rate sputtering. Our results include a description of the target fabrication procedures and sputter process parameters necessary to fabricate B4C and boron modulated thin film structures. (orig.)

  9. [4-(Methoxycarbonylbenzyl]triphenylphosphonium bromide hemihydrate

    Directory of Open Access Journals (Sweden)

    Shahid Hameed

    2008-02-01

    Full Text Available In the crystal structure of the title compound, C27H24O2P+·Br−·0.5H2O, there are intermolecular O—H...Br hydrogen bonds between the H atoms of the water of crystallization and the bromide anions. The three phenyl rings of the triphenylphosphonium moiety are at angles of 59.73 (15, 79.15 (14 and 82.81 (17° with the C/P/C planes.

  10. Exogenous bromide in the lactating rat influences iodine and bromide transfer to the suckling

    Czech Academy of Sciences Publication Activity Database

    Pavelka, Stanislav

    Athens : University of Athens, 2005, s. 322-327. [International Symposium on Trace Elements in Human: New Perspectives /5./. Athens (GR), 13.10.2005-15.10.2005] Institutional research plan: CEZ:AV0Z50110509 Keywords : bromide * iodine * rat Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition

  11. Boron cures cancer

    International Nuclear Information System (INIS)

    In this work the authors cite a few examples of the use of radiopharmaceuticals for diagnostic and therapeutic purposes in nuclear medicine. They point to the possibility of boron neutron capture therapy and the use for the neutron capture therapy of other light elements.

  12. Boron contamination in drinking - irrigation water and boron removal methods

    Directory of Open Access Journals (Sweden)

    Meltem Bilici Başkan

    2014-03-01

    Full Text Available Boron presents in IIIA group of periodic table and has high ionization capacity. Therefore it is classified as a metalloid. Average boron concentration in earth's crust is 10 mg/kg. It presents in the environment as a salts of Ca, Na, and Mg. Boron reserves having high concentration and economical extent are found mostly in Turkey and in arid, volcanic and high hydrothermal activity regions of U.S. as compounds of boron attached to oxygen. Boron is an essential micronutrient for plants, although it may be toxic at higher levels. The range in which it is converted from a nutrient to a contaminant is quite narrow. Boron presents in water environment as a boric acid and rarely borate salts. The main boron sources, whose presence is detected in surface waters, are urban wastes and industrial wastes, which can come from a wide range of different activities as well as several chemical products used in agriculture. In Turkey, the most pollutant toxic element in drinking and irrigation water is boron. Therefore boron removal is very important in terms of human health and agricultural products in high quality. Mainly boron removal methods from drinking water and irrigation water are ion exchange, ultrafiltration, reverse osmosis, and adsorption.

  13. Process for microwave sintering boron carbide

    International Nuclear Information System (INIS)

    A method of microwave sintering boron carbide comprises leaching boron carbide powder with an aqueous solution of nitric acid to form a leached boron carbide powder. The leached boron carbide powder is coated with a glassy carbon precursor to form a coated boron carbide powder. The coated boron carbide powder is consolidated in an enclosure of boron nitride particles coated with a layer of glassy carbon within a container for microwave heating to form an enclosed coated boron carbide powder. The enclosed coated boron carbide powder is sintered within the container for microwave heating with microwave energy

  14. Chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade aluminum oxide and aluminum oxide-boron carbide composite pellets

    Energy Technology Data Exchange (ETDEWEB)

    1981-01-01

    Aluminum oxide pellets are used in a reactor core as filler or spacers within fuel, burnable poison, or control rods. In order to be suitable for this purpose, the material must meet certain criteria for impurity content. The test methods in the standard are designed to show whether or not a given material meets these specifications. The following analytical procedures are described in detail: boron by titrimetry; separation of boron by mass spectrometry; isotopic composition by mass spectrometry; separation of halides by pyrohydrolysis; fluoride by ion-selective electrode; chloride, bromide, and iodide by amperometric microtitrimetry; trace elements by emission spectroscopy. (JMT)

  15. Methods of producing continuous boron carbide fibers

    Energy Technology Data Exchange (ETDEWEB)

    Garnier, John E.; Griffith, George W.

    2015-12-01

    Methods of producing continuous boron carbide fibers. The method comprises reacting a continuous carbon fiber material and a boron oxide gas within a temperature range of from approximately 1400.degree. C. to approximately 2200.degree. C. Continuous boron carbide fibers, continuous fibers comprising boron carbide, and articles including at least a boron carbide coating are also disclosed.

  16. Bromism from daily over intake of bromide salt.

    Science.gov (United States)

    Frances, C; Hoizey, G; Lamiable, D; Millart, H; Trenque, T

    2003-01-01

    Bromide intoxication today is an infrequent disease, but preparations containing bromide are still available in nonprescription compounds, on the French market. We report a casewith bromide intoxication due to daily over intake (approximately 20 tablets per day; i.e. total elemental bromide intake approximately 6 g/day) of calcium bromo-galactogluconate (Calcibronat) for 1.5 months. A 30-year-old woman with a long history of psychotropic drug abuse was hospitalized in a psychiatric department for neuropsychological manifestations. She presented a seriously disturbed mental status with confusion, disorientation, auditory and visual hallucinations, and loss of short-time memory. A markedly increased serum bromide level of 1717 mg/L (21.5 mEq/L) measured on the first day after her admission confirmed the diagnosis of chronic bromism suspected based on her symptomatology. During her hospitalization, bromide plasma concentrations were measured and monitored using inductively coupled plasma mass spectrometry, a sensitive and very specific method. After withdrawal of the drug, the symptoms improved within 8 days. Serial bromide concentrations gradually declined throughout nearly 2 months of monitoring, until she was discharged from the hospital. We found an elimination half-life of bromide in blood of approximately of 10 days. This case demonstrates that, while today bromism occurs infrequently, it should still be included in the differential diagnosis of neuropsychiatric symptoms. PMID:12733857

  17. Evaluation of N-ethyl-N-methyl-morpholinium bromide and N-ethyl-N-methyl-pyrrolidinium bromide as bromine complexing agents in vanadium bromide redox flow batteries

    International Nuclear Information System (INIS)

    Evolution of bromine gas in the positive half cell of the Generation 2 (G2) vanadium bromide (V/Br) battery during charging is a concern which can be resolved by the use of bromine complexing agents. In this paper, for the first time, we report the effect of the addition of two quaternary ammonium bromides; N-ethyl-N-methyl-morpholinium bromide (MEM) and N-ethyl-N-methyl-pyrrolidinium bromide (MEP) to the positive and negative half cell electrolytes of the V/Br. Cyclic voltammetry (CV), linear sweep voltammetry and electrochemical impedance spectroscopy (EIS) studies showed that the addition of MEM–MEP effectively reduce Br2 vapours. Although the presence of MEM and MEP did not affect the mechanism of the electrode reactions, performance tests conducted in lab scale V/Br cells employing the VF11 cation exchange membrane resulted in lower average cell efficiencies possibly due to the increase in membrane resistance caused by membrane fouling

  18. Glycopyrronium bromide for the treatment of chronic obstructive pulmonary disease.

    Science.gov (United States)

    Riario-Sforza, Gian Galeazzo; Ridolo, Erminia; Riario-Sforza, Edoardo; Incorvaia, Cristoforo

    2015-02-01

    Glycopyrronium bromide is a new long-acting muscarinic antagonist to be used once-daily, which is approved as a bronchodilator for the symptomatic maintenance treatment of adult patients with chronic obstructive pulmonary disease (COPD). In the Glycopyrronium bromide in chronic Obstructive pulmonary disease airWays trials, treatment with inhaled glycopyrronium bromide at 50 μg once daily achieved a significantly better lung function than placebo, as measured by the trough forced expiratory volume in 1 s in patients with moderate-to-severe COPD. The lung function improvement was maintained for up to 52 weeks. Other improved indexes were dyspnea scores, health status, exacerbation rates and time of exercise endurance. Studies comparing the efficacy of glycopyrronium versus tiotropium bromide found substantial equivalence of the two drugs. Glycopyrronium was generally well tolerated. These data add inhaled glycopyrronium bromide to the treatment of patients with moderate to severe COPD as an effective once-daily LAMA. PMID:25547422

  19. Kinetic spectrophotometric determination of bromide in clidinium-c drug

    Institute of Scientific and Technical Information of China (English)

    Ali Sheibani; M. Reza Shishehbore; Zahra Tavakolian Ardakani

    2011-01-01

    A simple, rapid and sensitive method has been described for the determination of the trace amounts of bromide. The method is based on the catalytic effect of bromide ion on the oxidation of methylene blue by bromate in sulfuric acid media. The reaction is monitored spectrophotometrically by measuring the decrease in the absorbance of methylene blue at 665 nm. Bromide was determined in the range of 0.05-1.90 μg/mL with the detection limit of 0.03 μg/mL. The relative standard deviations of five replicate determinations of 0.20 and 10.0 μg/mL of bromide were 2.4% and 1.8%, respectively. The influence of potential interfering ions and substances was studied. The method is applied to the analysis of bromide in clidinium-c tablet as a real sample.

  20. Sintered boron, production and properties

    International Nuclear Information System (INIS)

    Microhardness HV, tensile properties and Young modulus of sintered boron of different porosity were studied. It was shown that with density growth tensile properties improve. HV and brittle-ductile transition temperature Tsub(b) of sintered boron on the one hand and for silicon and titanium carbide on the other were compared and discussed. It was noted that the general level of HV and Tsub(b) for boron is rather high and at similar relative temperatures these characteristics are much higher. Temperature dependences of linear expansion coefficient, thermal capacity, thermal and temperature conductivity of sintered boron of 20% porosity were studied. Gruneisen parameter was evaluated

  1. Fivefold twinned boron carbide nanowires.

    Science.gov (United States)

    Fu, Xin; Jiang, Jun; Liu, Chao; Yuan, Jun

    2009-09-01

    Chemical composition and crystal structure of fivefold twinned boron carbide nanowires have been determined by electron energy-loss spectroscopy and electron diffraction. The fivefold cyclic twinning relationship is confirmed by systematic axial rotation electron diffraction. Detailed chemical analysis reveals a carbon-rich boron carbide phase. Such boron carbide nanowires are potentially interesting because of their intrinsic hardness and high temperature thermoelectric property. Together with other boron-rich compounds, they may form a set of multiply twinned nanowire systems where the misfit strain could be continuously tuned to influence their mechanical properties. PMID:19687534

  2. Selective oxidation of bromide in wastewater brines from hydraulic fracturing.

    Science.gov (United States)

    Sun, Mei; Lowry, Gregory V; Gregory, Kelvin B

    2013-07-01

    Brines generated from oil and natural gas production, including flowback water and produced water from hydraulic fracturing of shale gas, may contain elevated concentrations of bromide (~1 g/L). Bromide is a broad concern due to the potential for forming brominated disinfection byproducts (DBPs) during drinking water treatment. Conventional treatment processes for bromide removal is costly and not specific. Selective bromide removal is technically challenging due to the presence of other ions in the brine, especially chloride as high as 30-200 g/L. This study evaluates the ability of solid graphite electrodes to selectively oxidize bromide to bromine in flowback water and produced water from a shale gas operation in Southwestern PA. The bromine can then be outgassed from the solution and recovered, as a process well understood in the bromine industry. This study revealed that bromide may be selectively and rapidly removed from oil and gas brines (~10 h(-1) m(-2) for produced water and ~60 h(-1) m(-2) for flowback water). The electrolysis occurs with a current efficiency between 60 and 90%, and the estimated energy cost is ~6 kJ/g Br. These data are similar to those for the chlor-alkali process that is commonly used for chlorine gas and sodium hydroxide production. The results demonstrate that bromide may be selectively removed from oil and gas brines to create an opportunity for environmental protection and resource recovery. PMID:23726709

  3. Sodium bromide acts as a contrast material on DEXA scanning.

    Science.gov (United States)

    Chaisson, T G; Ryan, D H

    1994-02-01

    Subjects undergoing a series of procedures to determine body composition, including dual-energy x-ray absorptiometry (DEXA) scanning and extracellular water volume determination by bromide dilution, demonstrated abnormal DEXA scans in some cases. Oral doses of sodium bromide in the stomach were detected on total body DEXA scanning as contrast material. The physical principles that cause bromide to be imaged in a manner similar to calcium by the DEXA scanner are discussed so that other investigators may be aware of this potential pitfall in body composition analysis. PMID:8195668

  4. A new convenient access to highly functionalized ()-2-arylvinyl bromides

    Indian Academy of Sciences (India)

    Yubo Jiang; Chunxiang Kuang

    2009-11-01

    Highly functionalized ()-2-arylvinyl bromides were prepared in high yields through a new convenient access by acylation of ()-4-(2-bromovinyl)phenol with fatty and aromatic acids at room temperature using dicyclohexyl carbodiimide (DCC) and dimethylaminopyridine (DMAP).

  5. Kinetics and Mechanism of the Chlorate-Bromide Reaction.

    Science.gov (United States)

    Sant'Anna, Rafaela T P; Faria, Roberto B

    2015-11-01

    The chlorate-bromide reaction, ClO3(-) + 6Br(-) + 6H(+) → 3Br2 + Cl(-) + 3H2O, was followed at the Br3(-)/Br2 isosbestic point (446 nm). A fifth-order rate law was found: (1)/3 d[Br2]/dt = k[ClO3(-)][Br(-)][H(+)](3) (k = 5.10 × 10(-6) s(-1) L(4) mol(-4)) at 25 °C and I = 2.4 mol L(-1). At high bromide concentrations, the bromide order becomes close to zero, indicating a saturation profile on bromide concentration, similar to the chloride saturation profile observed in the chlorate-chloride reaction. A mechanism is proposed that considers the formation of the intermediate BrOClO2(2-), similar to the intermediate ClOClO2(2-) proposed in the mechanism of the chlorate-chloride reaction. PMID:26467822

  6. Methyl Bromide: Effective Pest Management Tool and Environmental Threat

    OpenAIRE

    Thomas, W. B.

    1996-01-01

    Methyl bromide is used extensively on a global basis as a pesticide against nematodes, weeds, insects, fungi, bacteria, and rodents. As a soil fumigant, it is used in significant quantities in the production of strawberry and tomato, as well as other agriculture commodities. Grain, fresh fruit, forestry products, and other materials are fumigated with methyl bromide to control pest infestations during transport and storage. Structures also are treated with this chemical to control wood-destro...

  7. Quantum Chemistry Study on Dissociation of Oxalyl Bromide

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The multi-bond dissociation dynamics of oxalyl bromide ((BrCO)2) has been investigated by DFT and CIS calculations. Upon the results, conclusion could be drawn that dissociation of C-Br bond of oxalyl bromide at the ground state (S0) is of barrierless. After the absorption of a photon, (BrCO)2 is excited to the first excited state and one of its C-Br bonds is broken to yield dissociate.

  8. Effects of ipratropium bromide and fenoterol aerosols in pulmonary emphysema.

    OpenAIRE

    Hughes, J A; Tobin, M. J.; Bellamy, D; Hutchison, D. C.

    1982-01-01

    In patients with radiological evidence of pulmonary emphysema the bronchodilator drugs fenoterol and ipratropium bromide produced a considerable increase in vital capacity and reduction in residual volume. The response to fenoterol was virtually complete 15 minutes after administration, but after ipratropium bromide vital capacity was still increasing at 60 minutes. The change in vital capacity was slightly greater with a combination of the two drugs than with either used alone. Changes in FE...

  9. Boron thermal regeneration system

    International Nuclear Information System (INIS)

    An ion exchanger which allows flow in both directions along a selected flow path is described. A separator plate divides the exchanger tank into two chambers each of which has a flow conduit so that flow may enter or leave from either chamber while prohibiting the resin particles from migrating from one side of the tank to the other. This ion exchanger permits a dual-directional flow process to be practised which results in immediate changes in the boron concentration within a nuclear reactor coolant system even if the ion exchanger resins have not been completely equilibrated during a previous operation. (author)

  10. BORONIZING OF STEEL

    Directory of Open Access Journals (Sweden)

    Arzum ULUKÖY

    2006-02-01

    Full Text Available Boride layer has many advantages in comparison with traditional hardening methods. The boride layer has high hardening value and keeps it's hardeness at high temperatures, and it also shows favorible properties, such as the resistance to wear, oxidation and corrosion. The process can be applied at variety of materials, for instance steel, cast iron, cast steel, nickel and cobalt alloys and cermets. In this rewiew, boronizing process properties, boride layer on steel surfaces and specifications and the factors that effect boride layer are examined

  11. Performance of large lanthanum bromide scintillators

    International Nuclear Information System (INIS)

    Cerium-doped lanthanum bromide, LaBr3(Ce), scintillator possesses several outstanding properties that make it an attractive choice for security, medical, and geophysical radiation detection applications. Among these properties are good density (5.1 g/cc), excellent energy resolution (∼3% full-width at half-maximum (FWHM) at Eγ=662 keV), brightness (>65,000 photon/MeV), and speed, (τd100 cc). The anisotropic thermal expansion exhibited by this material makes it difficult to grow large ingots due to the build up of internal stresses as it cools, causing fracturing. Recently, Saint-Gobain Crystals has achieved successful growths of large unfractured ingots, from which large detectors have been assembled (>150 cc). The outstanding properties seen in small pieces are retained up to at least 155 cc (the largest assembled into a single detector thus far). A cylindrical LaBr3(Ce=5%) crystal with dimensions of diameter=51 mm, and length=76 mm achieves energy resolution of 3.1% FWHM at 662 keV, and brightness of 165% of NaI with good uniformity throughout the crystal. Scintillation light yield and energy resolution have been examined as a function of crystal size and γ-ray energy. Spatial mapping of a large crystal was examined and shown to be uniform. Large crystals enable accurate measurements of the intrinsic γ-ray background from 138La (0.09% nat. abun., γ-ray emission at 1436 and 789 keV). This background is shown to scale appropriately in size with theoretical calculations

  12. Assessment of Ethidium bromide and Ethidium monoazide bromide removal from aqueous matrices by adsorption on cupric oxide nanoparticles.

    Science.gov (United States)

    Fakhri, Ali

    2014-06-01

    The present study was undertaken to develop an effective adsorbent and to study the adsorption of Ethidium bromide and Ethidium monoazide bromide from aqueous solution using the CuO nanoparticles. The characteristics of CuO nanoparticles were determined and found to have a surface area 89.59m(2)/g. Operational parameters such as pH, contact time and adsorbent concentration, initial concentration and temperature were also studied. The amount of removal increases with the increase in pH from one to seven and reaches the maximum when the pH is nine. Adsorption data fitted well with the Langmuir, Freundlich and Florry-Huggins models. The results show that the best fit was achieved with the Langmuir isotherm equation with maximum adsorption capacities of 0.868 and 0.662mg/g for Ethidium bromide and Ethidium monoazide bromide, respectively. The adsorption process was found to follow pseudo-second-order kinetics. The calculated thermodynamic parameters, namely ΔG, ΔH and ΔS showed that adsorption of Ethidium bromide and Ethidium monoazide bromide was spontaneous and endothermic under examined conditions. PMID:24630576

  13. Dietary boron, brain function, and cognitive performance.

    OpenAIRE

    Penland, J G

    1994-01-01

    Although the trace element boron has yet to be recognized as an essential nutrient for humans, recent data from animal and human studies suggest that boron may be important for mineral metabolism and membrane function. To investigate further the functional role of boron, brain electrophysiology and cognitive performance were assessed in response to dietary manipulation of boron (approximately 0.25 versus approximately 3.25 mg boron/2000 kcal/day) in three studies with healthy older men and wo...

  14. Banishing brittle bones with boron

    Energy Technology Data Exchange (ETDEWEB)

    A 6-month study indicates that boron, not even considered an essential nutrient for people and animals, may be a key to preventing osteoporosis, say nutritionist Forrest H. Nielsen and anatomist Curtiss D. Hunt at ARS' Grand Forks, North Dakota, Human Nutrition Research Center. They believe the results of the study - the first to look at the nutritional effects of boron in humans - will generate a lot of interest in the element. In the study, 12 postmenopausal women consumed a very low boron diet (0.25 milligrams per day) for 17 weeks then were given a daily 3-mg supplement - representing the boron intake from a well-balanced diet - for 7 more weeks. Within 8 days after the supplement was introduced, the lost 40 percent less calcium, one-third less magnesium, and slightly less phosphorus through the urine. In fact, their calcium and magnesium losses were lower than prestudy levels, when they were on their normal diets. Since boron isn't considered essential for people, there is not recommended intake and no boron supplement on the market. Nielsen says the supplement of sodium borate used in the study was specially prepared based on the amount of boron a person would get from a well-balanced diet containing fruits and vegetables. He says the average boron intake is about 1.5 mg - or half the experimental dose - but average means a lot of people get less and a lot get more. Hunt cautioned that large doses of boron can be toxic, even lethal. The lowest reported lethal dose of boric acid is about 45 grams (1.6 ounces) for an adult and only 2 grams (0.07 ounce) for an infant.

  15. Palladium-catalyzed cross-coupling reactions of aryl boronic acids with aryl halides in water.

    Science.gov (United States)

    Wang, Shaoyan; Zhang, Zhiqiang; Hu, Zhizhi; Wang, Yue; Lei, Peng; Chi, Haijun

    2009-01-01

    An efficient Suzuki cross-coupling reaction using a variety of aryl halides in neat water was developed. The Pd-catalyzed reaction between aryl bromides or chlorides and phenyl boronic acids was compatible with various functional groups and affords biphenyls in good to excellent yields without requirement of organic cosolvents. The air stability and solubility in water of the palladium-phosphinous acid complexes were considered to facilitate operation of the coupling reaction and product isolation. The reaction conditions including Pd catalyst selection, temperature, base and catalyst recoverability were also investigated. PMID:25084408

  16. Lattice dynamics of α boron and of boron carbide

    International Nuclear Information System (INIS)

    The atomic structure and the lattice dynamics of α boron and of B4C boron carbide have been studied by Density Functional Theory (D.F.T.) and Density Functional Perturbation Theory (D.F.P.T.). The bulk moduli of the unit-cell and of the icosahedron have been investigated, and the equation of state at zero temperature has been determined. In α boron, Raman diffusion and infrared absorption have been studied under pressure, and the theoretical and experimental Grueneisen coefficients have been compared. In boron carbide, inspection of the theoretical and experimental vibrational spectra has led to the determination of the atomic structure of B4C. Finally, the effects of isotopic disorder have been modeled by an exact method beyond the mean-field approximation, and the effects onto the Raman lines has been investigated. The method has been applied to isotopic alloys of diamond and germanium. (author)

  17. A new and effective approach to boron removal by using novel boron-specific fungi isolated from boron mining wastewater.

    Science.gov (United States)

    Taştan, Burcu Ertit; Çakir, Dilara Nur; Dönmez, Gönül

    2016-01-01

    Boron-resistant fungi were isolated from the wastewater of a boron mine in Turkey. Boron removal efficiencies of Penicillium crustosum and Rhodotorula mucilaginosa were detected in different media compositions. Minimal Salt Medium (MSM) and two different waste media containing molasses (WM-1) or whey + molasses (WM-2) were tested to make this process cost effective when scaled up. Both isolates achieved high boron removal yields at the highest boron concentrations tested in MSM and WM-1. The maximum boron removal yield by P. crustosum was 45.68% at 33.95 mg l(-1) initial boron concentration in MSM, and was 38.97% at 42.76 mg l(-1) boron for R. mucilaginosa, which seemed to offer an economically feasible method of removing boron from the effluents. PMID:26877036

  18. Structural characterization of electrodeposited boron

    Indian Academy of Sciences (India)

    Ashish Jain; C Ghosh; T R Ravindran; S Anthonysamy; R Divakar; E Mohandas; G S Gupta

    2013-12-01

    Structural characterization of electrodeposited boron was carried out by using transmission electron microscopy and Raman spectroscopy. Electron diffraction and phase contrast imaging were carried out by using transmission electron microscopy. Phase identification was done based on the analysis of electron diffraction patterns and the power spectrum calculated from the lattice images from thin regions of the sample. Raman spectroscopic examination was carried out to study the nature of bonding and the allotropic form of boron obtained after electrodeposition. The results obtained from transmission electron microscopy showed the presence of nanocrystallites embedded in an amorphous mass of boron. Raman microscopic studies showed that amorphous boron could be converted to its crystalline form at high temperatures.

  19. Boron diffusion in silicon devices

    Science.gov (United States)

    Rohatgi, Ajeet; Kim, Dong Seop; Nakayashiki, Kenta; Rounsaville, Brian

    2010-09-07

    Disclosed are various embodiments that include a process, an arrangement, and an apparatus for boron diffusion in a wafer. In one representative embodiment, a process is provided in which a boric oxide solution is applied to a surface of the wafer. Thereafter, the wafer is subjected to a fast heat ramp-up associated with a first heating cycle that results in a release of an amount of boron for diffusion into the wafer.

  20. Interaction of cephradine monohydrate with Cetyldimethylethylammonium Bromide

    International Nuclear Information System (INIS)

    Highlights: • We carry out the interaction of CDM drugs with CDMEAB conductometrically. • We examine the effect of drugs on the critical micelle concentration of CDMEAB. • Two critical micelle concentrations are obtained for drug-CDMEAB system. • Electrostatic and hydrophobic interactions between drug and surfactant are proposed. • Effect of KCl and K2SO4 is observed on interaction between drug and surfactant. -- Abstract: Interaction of cephradine monohydrate (CDM) with Cetyldimethylethylammonium Bromide (CDMEAB) has been studied by conductance measurements in pure form and in the presence of salts like potassium chloride (KCl) and potassium sulphate (K2SO4) over the temperature range of (298.15 to 318.15) K. From conductivity vs. surfactant concentration plots, two critical micelle concentrations like c1∗ and c1∗ were obtained for (CDM + CDMEAB) systems. The variation of c∗ values of CDMEAB in the presence of CDM is the indication of the interaction between CDM and CDMEAB. For the (CDM + CDMEAB) system, the values of c∗ values are higher in magnitude in contrast to that of pure CDMEAB in water over the range in temperature studied. In aqueous solutions of KCl and K2SO4, the c∗ values are changed with the increase of the concentration of salts and hence the micellization is dependent on salt concentration. The ΔGm0 values were negative and the spontaneity of micellization process is found to be increased with increase of temperature. The values of ΔH1,m0 and ΔS1,m0 indicated that the drug mediated CDMEAB aggregation in water was controlled at lower temperatures while at higher temperatures the aggregation was both enthalpy and entropy controlled. The ΔH2,m0 and ΔS2,m0 values revealed that the micellization in water was both enthalpy and entropy controlled at lower and higher temperatures though the effect of entropy at middle temperature was dominant. The results indicated that binding interactions between CDM and CDMEAB are both

  1. Boron Fullerenes: A First-Principles Study

    Directory of Open Access Journals (Sweden)

    Gonzalez Szwacki Nevill

    2007-01-01

    Full Text Available AbstractA family of unusually stable boron cages was identified and examined using first-principles local-density functional method. The structure of the fullerenes is similar to that of the B12icosahedron and consists of six crossing double-rings. The energetically most stable fullerene is made up of 180 boron atoms. A connection between the fullerene family and its precursors, boron sheets, is made. We show that the most stable boron sheets are not necessarily precursors of very stable boron cages. Our finding is a step forward in the understanding of the structure of the recently produced boron nanotubes.

  2. Intensification of sonochemical degradation of malachite green by bromide ions.

    Science.gov (United States)

    Moumeni, Ouarda; Hamdaoui, Oualid

    2012-05-01

    Sonochemical oxidation has been investigated as a viable advanced oxidation process (AOP) for the destruction of various pollutants in water. Ultrasonic irradiation generates ()OH radicals that can recombine, react with other gaseous species present in the cavity, or diffuse out of the bubble into the bulk liquid medium where they are able to react with solute molecules. The extent of degradation of an organic dye such as malachite green (MG) is limited by the quantity of hydroxyl radicals diffused from cavitation bubbles. In this work, the effect of bromide ions on sonolytic degradation of MG was investigated. The obtained results clearly demonstrated the considerable enhancement of sonochemical destruction of MG in the presence of bromide. No significant differences were observed in the presence of chloride and sulfate, excluding the salting-out effect. Positive effect of bromide ions, which increases with increasing bromide level and decreasing MG concentration, is due to the generation of dibromine radical anion (Br(2)(-)) formed by reaction of Br(-) with ()OH radicals followed by rapid complexation with another anion. The generated Br(2)(-) radicals, reactive but less than ()OH, are likely able to migrate far from the cavitation bubbles towards the solution bulk and are suitable for degradation of an organic dye such as MG. Additionally, Br(2)(-) radicals undergo radical-radical recombination at a lesser extent than hydroxyl radicals and would be more available than ()OH for substrate degradation, both at the bubble surface and in the solution bulk. This effect compensates for the lower reactivity of Br(2)(-) compared to ()OH toward organic substrate. Addition of bromide to natural and sea waters induces a slight positive effect on MG degradation. In the absence of bromide, ultrasonic treatment for the removal of MG was promoted in complex matrices such as natural and sea waters. PMID:21911308

  3. Oxidation of manganese(II) during chlorination: role of bromide.

    Science.gov (United States)

    Allard, S; Fouche, L; Dick, J; Heitz, A; von Gunten, U

    2013-08-01

    The oxidation of dissolved manganese(II) (Mn(II)) during chlorination is a relatively slow process which may lead to residual Mn(II) in treated drinking waters. Chemical Mn(II) oxidation is autocatalytic and consists of a homogeneous and a heterogeneous process; the oxidation of Mn(II) is mainly driven by the latter process. This study demonstrates that Mn(II) oxidation during chlorination is enhanced in bromide-containing waters by the formation of reactive bromine species (e.g., HOBr, BrCl, Br2O) from the oxidation of bromide by chlorine. During oxidation of Mn(II) by chlorine in bromide-containing waters, bromide is recycled and acts as a catalyst. For a chlorine dose of 1 mg/L and a bromide level as low as 10 μg/L, the oxidation of Mn(II) by reactive bromine species becomes the main pathway. It was demonstrated that the kinetics of the reaction are dominated by the adsorbed Mn(OH)2 species for both chlorine and bromine at circumneutral pH. Reactive bromine species such as Br2O and BrCl significantly influence the rate of manganese oxidation and may even outweigh the reactivity of HOBr. Reaction orders in [HOBr]tot were found to be 1.33 (±0.15) at pH 7.8 and increased to 1.97 (±0.17) at pH 8.2 consistent with an important contribution of Br2O which is second order in [HOBr]tot. These findings highlight the need to take bromide, and the subsequent reactive bromine species formed upon chlorination, into account to assess Mn(II) removal during water treatment with chlorine. PMID:23859083

  4. Radioactive bromide partition test in the diagnosis of tuberculous meningitis

    International Nuclear Information System (INIS)

    The utility of the radioactive bromide partition test in differentiating tuberculous meningitis (TBM) from other forms of meningitis has been assessed. The test was carried out in 19 patients with TBM, 6 patients with partially treated pyogenic meningitis and 17 non-meningitis controls. Eighteen of the 19 TBM patients gave bromide partition ratio (BPR) value below 1.3 while the value was above this level in all control patients including partially treated meningitis. The results indicate that the test is useful in the differential diagnosis of TBM. (author)

  5. Chemistry of pyrrolizines; reactions with cyanogen bromide and trifluoroacetic anhydride

    OpenAIRE

    Verboom, W.; Visser, G.W.; Reinhoudt, D.N.

    1982-01-01

    Interaction of the pyrrolizine 3 with cyanogen bromide in a tetrahydrofuran/water mixture affords addition to the enamine double bond with formation of 5 which can be aromatized to 6 by silica gel. Reaction of 6 with cyanogen bromide in the same solvent mixture yields the indoline 8a which structure is proved in a chemical way by conversion of the product into the aldehyde 8d. The different reaction pathway is discussed in terms of steric hindrance by the ester groups. Treatment of 6 with tri...

  6. Stability analysis for complexes in calcium-alkali bromide solutions

    International Nuclear Information System (INIS)

    We discuss the dependence of the stability of tetrahedral complexes in molten halide mixtures on the halogen species. This is done by calculating the equilibrium concentration of (CaBr4)2- complexes in calcium-alkali bromide solutions as a function of composition, in comparison with earlier calculations on the calcium-alkali chloride systems. The comparison supports a possible trend of increasing stability from chlorides to bromides, provided that halogen polarizability or chemical bonding contribute appreciably to the binding of a complex. Supporting evidence is noted and further experiments are suggested. (author). 10 refs, 2 figs

  7. Wettability of boron carbide

    International Nuclear Information System (INIS)

    The wettability of boron carbide has been examined by means of the sessile drop method, using the following candidate alloys: (96wt%AG-4wt%Ti), (Ag-26.5wt%Cu-3wt%Ti), (Sn-10wt%Ag-4wt%Ti), Sn(99.95wt%) and Al(99.99wt%). The results show that B4C is completely wetted by the Ag-based alloys. Sn-10wt%Ag-4wt%Ti alloy and pure Al partly wet the B4C surface, while pure Sn does not wet B4C at all. For all the alloys used, except pure Sn, a reaction layer was observed at the interface between the ceramic part and the metal drop. Although the spreading kinetics of the Al-drop was much slower compared with the Ti-containing alloys, the reaction rate was considerably higher in the former case. This suggests that aluminium is an attractive candidate material for brazing of B4C. Formation of the low melting B2O3 at the B4C surface may cause oxidation of the filler metal during joining, which, in turn, leads to a low bond strength

  8. Thermal conductivity of boron carbide-boron nitride composites

    International Nuclear Information System (INIS)

    This paper reports that because of their preferred orientation, the addition of boron nitride dispersions to hot-pressed boron carbide was found to result in a considerable degree of anisotropy in thermal conductivity of the resulting composite, indicated by an increase in the thermal conductivity perpendicular to the hot-pressing direction by as much as a factor of 3 at the highest boron nitride volume fractions of this study, and a decrease in the thermal conductivity parallel to the hot-pressing direction by as much as a factor of 2. The composite data were found to be below the values expected from composite theory, which may represent indirect evidence for the existence of an interfacial thermal barrier

  9. The boron trifluoride nitromethane adduct

    Science.gov (United States)

    Ownby, P. Darrell

    2004-02-01

    The separation of the boron isotopes using boron trifluoride·organic-donor, Lewis acid·base adducts is an essential first step in preparing 10B enriched and depleted crystalline solids so vital to nuclear studies and reactor applications such as enriched MgB 2, boron carbide, ZrB 2, HfB 2, aluminum boron alloys, and depleted silicon circuits for radiation hardening and neutron diffraction crystal structure studies. The appearance of this new adduct with such superior properties demands attention in the continuing search for more effective and efficient means of separation. An evaluation of the boron trifluoride nitromethane adduct, its thermodynamic and physical properties related to large-scale isotopic separation is presented. Its remarkably high separation factor was confirmed to be higher than the expected theoretical value. However, the reportedly high acid/donor ratio was proven to be an order of magnitude lower. On-going research is determining the crystal structure of deuterated and 11B enriched 11BF 3·CD 3NO 2 by X-ray and neutron diffraction.

  10. Boron carbide nanolumps on carbon nanotubes

    Science.gov (United States)

    Lao, J. Y.; Li, W. Z.; Wen, J. G.; Ren, Z. F.

    2002-01-01

    Boron carbide nanolumps are formed on the surface of multiwall carbon nanotubes by a solid-state reaction between boron and carbon nanotubes. The reaction is localized so that the integrity of the structure of carbon nanotubes is maintained. Inner layers of multiwall carbon nanotubes are also bonded to boron carbide nanolumps. These multiwall carbon nanotubes with boron carbide nanolumps are expected to be the ideal reinforcing fillers for high-performance composites because of the favorable morphology.

  11. Radioactive bromide partition test in early diagnosis of tuberculous meningitis

    International Nuclear Information System (INIS)

    Use of the radioactive bromide partition test in the early diagnosis of tuberculous meningitis is described briefly. Results of the (1) normal control group, (2) tuberculous menigitis group and (3) non-tuberculous lymphocytic meningitis are reported. Dose rates administered are specified. (K.B.)

  12. Depleting methyl bromide residues in soil by reaction with bases

    Science.gov (United States)

    Despite generally being considered the most effective soil fumigant, methyl bromide (MeBr) use is being phased out because its emissions from soil can lead to stratospheric ozone depletion. However, a large amount is still currently used due to Critical Use Exemptions. As strategies for reducing the...

  13. Reactive films for mitigating methyl bromide emissions from fumigated soil

    Science.gov (United States)

    Emissions of methyl bromide (MeBr) from agricultural fumigation can lead to depletion of the stratospheric ozone layer, and so its use is being phased out. However, as MeBr is still widely used under Critical Use Exemptions, strategies are still required to control such emissions. In this work, nove...

  14. Bromide interference with iodine metabolism in the rat

    Czech Academy of Sciences Publication Activity Database

    Pavelka, Stanislav

    Hersonissos: ISTERH, 2007. E073-E073. [Conference International Society for Trace Element Research in Humans /8./. 21.10.2007-26.10.2007, Hersonisssos] R&D Projects: GA AV ČR(CZ) KJB401630701 Institutional research plan: CEZ:AV0Z50110509 Keywords : spr2 * bromide * iodine * metabolism Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition

  15. Bromide interference with iodine metabolism in the rat

    Czech Academy of Sciences Publication Activity Database

    Pavelka, Stanislav

    2008-01-01

    Roč. 24, Suppl.1 (2008), S97-S98. ISSN 0742-2091. [Trace Elements in Diet , Nutrition and Health. 21.10.2008-26.10.2008, Hersonissos] Institutional research plan: CEZ:AV0Z50110509 Keywords : cpr1 * bromide * iodine * metabolism Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition

  16. Residues resulting from fumigation of food commodities with methyl bromide

    International Nuclear Information System (INIS)

    An investigation was undertaken to determine the nature and significance of residues remaining in methyl bromide-fumigated commodities using radiotracer techniques (14C-methyl bromide). Experiments with corn showed that the germ part of the kernel contained nearly half of the total 14C-residue remaining in the seed. Also preliminary tests with granny smith apples revealed that considerable residue may remain in seeds of treated apples with less in skin and the least in the fleshy pulp. In fumigated corn, fractionation revealed that radioactive residues were distributed throughout albumins, globulins, Zein 1, Zein 2 and glutelin with a large part in the aqueous extract (amino acids). Further investigation emphasized the characterization of volatile substances resulting from alkali treatment. It was found that methyl bromide readily methylated methionine and this constitutes a major site of methylation. A component of the volatile fraction was dimethyl sulfoxide, probably a product of oxidation of dimethyl sulphide. Work is in progress to determine whether methyl bromide will methylate purine and pyrimidine components. (author)

  17. Methyl bromide phase out could affect future reforestation efforts

    Science.gov (United States)

    Methyl bromide has long been an integral component in producing healthy tree seedlings in forest nurseries of California, Idaho, Montana, Oregon and Washington. The fumigant was supposed to be completely phased out of use in the United States of America by 2005, but many forest nurseries continue to...

  18. Effects of exogenous bromide on the metabolism of iodine

    Czech Academy of Sciences Publication Activity Database

    Pavelka, Stanislav

    Athens : University of Athens, 2003 - (Ermidou-Pollet, S.; Pollet, S.), s. 615-624 [Trace Elements in Human : New Perspectives /4./. Athens (GR), 09.10.2003-11.10.2003] Institutional research plan: CEZ:AV0Z5011922 Keywords : bromide * iodine * metabolism Subject RIV: ED - Physiology

  19. Palladium(0)-catalyzed methylenecyclopropanation of norbornenes with vinyl bromides.

    Science.gov (United States)

    Mao, Jiangang; Bao, Weiliang

    2014-05-16

    Highly strained methylenecyclopropane derivatives have been achieved via a novel and efficient Pd(0)-catalyzed domino reaction. The formal [2 + 1] cycloaddition reaction of vinyl bromides to norbornenes involves a Heck-type coupling and a C(sp(2))-H bond activation. PMID:24784731

  20. NEW ADVANCES IN BORON SOIL CHEMISTRY

    Science.gov (United States)

    Boron is an essential micronutrient element required for plant growth. Boron deficiency is wide-spread in crop plants throughout the world especially in coarse-textured soils in humid areas. Boron toxicity can also occur, especially in arid regions under irrigation. Plants respond directly to the...

  1. Boron doping a semiconductor particle

    Science.gov (United States)

    Stevens, Gary Don; Reynolds, Jeffrey Scott; Brown, Louanne Kay

    1998-06-09

    A method (10,30) of boron doping a semiconductor particle using boric acid to obtain a p-type doped particle. Either silicon spheres or silicon powder is mixed with a diluted solution of boric acid having a predetermined concentration. The spheres are dried (16), with the boron film then being driven (18) into the sphere. A melt procedure mixes the driven boron uniformly throughout the sphere. In the case of silicon powder, the powder is metered out (38) into piles and melted/fused (40) with an optical furnace. Both processes obtain a p-type doped silicon sphere with desired resistivity. Boric acid is not a restricted chemical, is inexpensive, and does not pose any special shipping, handling, or disposal requirements.

  2. Bromide interference with iodine metabolism: goitrogenic and whole-body effects of excessive inorganic bromide in the rat

    Czech Academy of Sciences Publication Activity Database

    Pavelka, Stanislav

    Oxford: Academic Press, 2009 - (Preedy, V.; Burrow, G.; Watson, R.), s. 587-595 ISBN 978-0-12-374135-6 Grant ostatní: EC(XE) LSHG-CT-2004-511978 Institutional research plan: CEZ:AV0Z50110509 Keywords : bromide * iodine * metabolism Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition

  3. Association of defects in lead chloride and lead bromide: Ionic conductivity and dielectric loss measurements

    NARCIS (Netherlands)

    Brom, W.E. van den; Schoonman, J.; Wit, J.H.W. de

    1972-01-01

    The ionic conductivity data of pure and doped lead bromide without associated defects are used in order to explain the anomalous conductivity behaviour of copper (I) bromide and lead oxide-doped lead-bromide crystals. In these crystals precipitated dopant and associated defects are present. The asso

  4. 40 CFR 180.519 - Bromide ion and residual bromine; tolerances for residues.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Bromide ion and residual bromine... Tolerances § 180.519 Bromide ion and residual bromine; tolerances for residues. (a) General. The food additives, bromide ion and residual bromine, may be present in water, potable in accordance with...

  5. Detection of lipopolysaccharides by ethidium bromide staining after sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

    OpenAIRE

    Kido, N; Ohta, M; Kato, N

    1990-01-01

    A rapid and easy method for staining lipopolysaccharides with ethidium bromide is described. Lipopolysaccharides could be visualized by ethidium bromide with almost the same sensitivity as found with the silver-staining method in less than 30 min. The ethidium bromide-staining method was particularly suitable for staining lipopolysaccharides possessing acidic O-specific polysaccharides, which were poorly visualized by silver staining.

  6. Boron steel. I Part. Preparation

    International Nuclear Information System (INIS)

    With the advent of the first nuclear reactors arise the need for control rods and shielding duties for some types of radiations. One of the materials used for this purpose has been the high boron steel. This paper describes the melting and casting procedures employed for the production, at laboratory scale, of steels with Boron content ranging from 1 to 4 per cent, as well as the metallographic and X-Ray techniques used for the identification of the present phases. The electrolytic technique employed for the isolation of the Fe2B phase and its subsequent X-Ray identification has proved to be satisfactory. (Author) 11 refs

  7. Shear amorphization of boron suboxide

    International Nuclear Information System (INIS)

    We report for the first time the shear-induced local amorphization of boron suboxide subjected to nanoindentation. The amorphous bands have a width of ∼1–3 nm and a length of 200–300 nm along the (01¯11) crystal plane. We show direct experimental evidence that the amorphous shear bands of boron suboxide are driven from the coalescence of dislocation loops under high shear stresses. These observations provide insights into the microscopic deformation and failure of high-strength and lightweight ceramics

  8. Thermal conductivity of boron carbides

    Science.gov (United States)

    Wood, C.; Emin, D.; Gray, P. E.

    1985-01-01

    Knowledge of the thermal conductivity of boron carbide is necessary to evaluate its potential for high-temperature thermoelectric energy conversion applications. Measurements have been conducted of the thermal diffusivity of hot-pressed boron carbide BxC samples as a function of composition (x in the range from 4 to 9), temperature (300-1700 K), and temperature cycling. These data, in concert with density and specific-heat data, yield the thermal conductivities of these materials. The results are discussed in terms of a structural model that has been previously advanced to explain the electronic transport data. Some novel mechanisms for thermal conduction are briefly discussed.

  9. Mechanical properties of boron coatings

    International Nuclear Information System (INIS)

    Internal stress of coatings will cause reliability problems, such as adhesion failure and peeling. We measured the internal stress in boron coatings, which was prepared by the ion plating method, with an apparatus based on the optically levered laser technique. The boron coatings exhibited large compressive stress in the range from -0.5 GPa to -2.6 GPa. It was found that these compressive stresses were decreasing functions of the deposition rate and were increasing functions of the ion bombardment energy. ((orig.))

  10. Boron-enhanced diffusion of boron from ultralow-energy boron implantation

    International Nuclear Information System (INIS)

    The authors have investigated the diffusion enhancement mechanism of BED (boron enhanced diffusion), wherein the boron diffusivity is enhanced three to four times over the equilibrium diffusivity at 1,050 C in the proximity of a silicon layer containing a high boron concentration. It is shown that BED is associated with the formation of a fine-grain polycrystalline silicon boride phase within an initially amorphous Si layer having a high B concentration. For 0.5 keV B+, the threshold implantation dose which leads to BED lies between 3 x 1014 and of 1 x 1015/cm-2. Formation of the shallowest possible junctions by 0.5 keV B+ requires that the implant dose be kept lower than this threshold

  11. A comparison of the effect of intranasal desmopressin and intramuscular hyoscine N-butyl bromide combination with intramuscular hyoscine N-butyl bromide alone in acute renal colic

    OpenAIRE

    Abdol-Reza Kheirollahi; Mohammad Tehrani; Mohammad Bashashati

    2010-01-01

    Background: Patients with acute renal colic usually require immediate diagnosis and treatment. In this clinical trial analgesic effect of hyoscine N-butyl bromide and desmopressin combination in comparison with hyoscine N-butyl bromide alone in patients with acute renal colic induced by urinary stones was assessed. Methods: The study included 114 patients randomly allocated in two groups (A and B). Patients in group A received 20 mg intramuscular hyoscine N-butyl bromide at admission tim...

  12. Analytical boron diffusivity model in silicon for thermal diffusion from boron silicate glass film

    Science.gov (United States)

    Kurachi, Ikuo; Yoshioka, Kentaro

    2015-09-01

    An analytical boron diffusivity model in silicon for thermal diffusion from a boron silicate glass (BSG) film has been proposed in terms of enhanced diffusion due to boron-silicon interstitial pair formation. The silicon interstitial generation is considered to be a result of the silicon kick-out mechanism by the diffused boron at the surface. The additional silicon interstitial generation in the bulk silicon is considered to be the dissociation of the diffused pairs. The former one causes the surface boron concentration dependent diffusion. The latter one causes the local boron concentration dependent diffusion. The calculated boron profiles based on the diffusivity model are confirmed to agree with the actual diffusion profiles measured by secondary ion mass spectroscopy (SIMS) for a wide range of the BSG boron concentration. This analytical diffusivity model is a helpful tool for p+ boron diffusion process optimization of n-type solar cell manufacturing.

  13. Analysis of boronized wall in LHD

    International Nuclear Information System (INIS)

    Boronization has been carried out in some experimental fusion devices as one of wall conditioning Methods. The well-known merits of the boronization are as follows: 1) coated-boron on the first wall has strong gettering function for oxygen impurities and oxygen has been kept into boron films as a boron-oxide and 2) boron film covers first wall with apparently low Z materials facing the plasma. However, an operation scenario of boronization for next generation devices such as ITER is not optimized. In this paper, we discuss an optimized method of coated film uniformity in a wide area and a lifetime of boron film as an oxygen getter using experimental data in the large helical device (LHD). In LHD, boronization by glow discharges has been carried out a few times during each experimental campaign. Helium-diborane mixtured gas is used and plasma facing components (PFM) are stainless steel (SS) for the first wall and carbon for the divertor plates kept in the room temperature. Material probes made of SS316 and Si were installed in the vacuum vessel and exposed during the experimental campaign. Depth profiles of their impurities were analyzed using the X-ray Photoelectron Spectroscopy (XPS) and the Auger electron spectroscopy (AES). Two types of gettering process by boron film have been investigated. One is the process during boronization and the other is that after boronization. Concerning a lifetime of boron film, the distribution of oxygen near the top surface region (0 to 20 nm) indicates a process of oxygen gettering, it shows a contribution after boronization. In this paper, these kinds of process using material probes are shown. (authors)

  14. Boron Poisoning of Plutonium Solutions

    International Nuclear Information System (INIS)

    The results of a theoretical investigation into the possible relaxation of criticality concentration limits in wet chemical reprocessing plants, due to the introduction of boron poisoning, are reported. The following systems were considered: 1. 1 in. stainless steel tubes filled with boron carbide at various pitches in homogeneous mixtures of 239Pu (NO3)4, 5H2O and water. 2. 1 in. and 2 in borosilicate glass Raschig rings in homogeneous mixtures of 239Pu (NO3)4, 5H2O and water. 3. The concentration of natural boron required for k∞ = 1 in homogeneous mixtures of 239Pu-B-H2O. The method of calculation was Monte Carlo using the GEM code with Nuclear Data File cross-sections. The Raschig rings used are those commercially available. The core model consisted of a cubic arrangement of unit cubes of solution within each of which a Raschig ring was centrally placed. The arrangement was such that the rings were regularly stacked with axes parallel, but the side of the unit cube was fixed to preserve the random packing density. Comparison is made with other reported results on boron poisoning. (author)

  15. Boron sorption characteristics in resins

    International Nuclear Information System (INIS)

    The purpose of boron addition in a nuclear power plant is to control the reactivity. In PHWRs, it is injected into the moderator system in the form of boric anhydride solution, while in PHWRs, it is added to the primary heat transport system in the form of boric acid solution. The required boron levels in PHWRs are controlled by valving in strong base anion exchangers having exchangeable species in OD- form while in PHWRs, the same can be achieved by restoring to the use of Boron Thermal Regeneration System (BTRS). This system operates on the principle of existence of different amounts of various polyborate ions at different temperatures, solution pH's and the boric acid concentrations and on the reversible sorption of these polyions on strong base anion exchange resins. This report describes the salient features of boron sorption characteristics on four types of anion exchange resins, based on experimental data generated in the chemical laboratories of Reactor Engineering Division of the Bhabha Atomic Research Centre, Bombay. The report further makes an attempt to calculate the pH of the resin and solution phases and the percentages of different polyborates and undissociated boric acid, under the experimental conditions investigated. (author). 30 refs., 4 figs., 20 tables

  16. Advanced microstructure of boron carbide.

    Science.gov (United States)

    Werheit, Helmut; Shalamberidze, Sulkhan

    2012-09-26

    The rhombohedral elementary cell of the complex boron carbide structure is composed of B(12) or B(11)C icosahedra and CBC, CBB or B□B (□, vacancy) linear arrangements, whose shares vary depending on the actual chemical compound. The evaluation of the IR phonon spectra of isotopically pure boron carbide yields the quantitative concentrations of these components within the homogeneity range. The structure formula of B(4.3)C at the carbon-rich limit of the homogeneity range is (B(11)C) (CBC)(0.91) (B□B)(0.09) (□, vacancy); and the actual structure formula of B(13)C(2) is (B(12))(0.5)(B(11)C)(0.5)(CBC)(0.65)(CBB)(0.16) (B□B)(0.19), and deviates fundamentally from (B(12))CBC, predicted by theory to be the energetically most favourable structure of boron carbide. In reality, it is the most distorted structure in the homogeneity range. The spectra of (nat)B(x)C make it evident that boron isotopes are not randomly distributed in the structure. However, doping with 2% silicon brings about a random distribution. PMID:22945740

  17. Boron isotopes in geothermal systems

    International Nuclear Information System (INIS)

    Boron is a highly mobile element and during water-rock reactions, boron is leached out of rocks with no apparent fractionation. In geothermal systems where the water recharging the systems are meteoric in origin, the B isotope ratio of the geothermal fluid reflects the B isotope ratio of the rocks. Seawater has a distinctive B isotope ratio and where seawater recharges the geothermal system, the B isotope ratio of the geothermal system reflects the mixing of rock derived B and seawater derived B. Any deviations of the actual B isotope ratio of a mixture reflects subtle differences in the water-rock ratios in the cold downwelling limb of the hydrothermal system. This paper will present data from a variety of different geothermal systems, including New Zealand; Iceland; Yellowston, USA; Ibusuki, Japan to show the range in B isotope ratios in active geothermal systems. Some of these systems show well defined mixing trends between seawater and the host rocks, whilst others show the boron isotope ratios of the host rock only. In geothermal systems containing high amounts of CO2 boron isotope ratios from a volatile B source can also be inferred. (auth)

  18. Ru-Catalysed C–H Arylation of Indoles and Pyrroles with Boronic Acids: Scope and Mechanistic Studies

    Science.gov (United States)

    Sollert, Carina; Devaraj, Karthik; Orthaber, Andreas; Gates, Paul J; Pilarski, Lukasz T

    2015-01-01

    The Ru-catalysed C2–H arylation of indoles and pyrroles by using boronic acids under oxidative conditions is reported. This reaction can be applied to tryptophan derivatives and tolerates a wide range of functional groups on both coupling partners, including bromides and iodides, which can be further derivatised selectively. New indole-based ruthenacyclic complexes are described and investigated as possible intermediates in the reaction. Mechanistic studies suggest the on-cycle intermediates do not possess a para-cymene ligand and that the on-cycle metalation occurs through an electrophilic attack by the Ru centre. PMID:25689052

  19. Raman spectroscopy of boron carbides and related boron-containing materials

    International Nuclear Information System (INIS)

    Raman spectra of crystalline boron, boron carbide, boron arsenide (B12As2), and boron phosphide (B12P2) are reported. The spectra are compared with other boron-containing materials containing the boron icosahedron as a structural unit. The spectra exhibit similar features some of which correlate with the structure of the icosahedral units of the crystals. The highest Raman lines appear to be especially sensitive to the B-B distance in the polar triangle of the icosahedron. Such Raman structural markers are potentially useful in efforts to tailor electronic properties of these high temperature semiconductors and thermoelectrics

  20. [2,6-Bis(dimethylaminomethylphenyl]selenium bromide monohydrate

    Directory of Open Access Journals (Sweden)

    Richard A. Varga

    2010-04-01

    Full Text Available In the title hydrated molecular salt, C12H19N2Se+·Br−·H2O, the two independent bromide anions lie on a twofold rotation axis. Strong intramolecular N→Se interactions [2.185 (3 and 2.181 (3 Å] are established by both N atoms of the organic group in the cation, in trans positions to each other, with an N—Se—N angle of 161.6 (1°, resulting in a T-shaped (C,N,N′Se core. In the crystal, dimeric associations are formed by Br...Se [3.662 (2 Å] and Br...H interactions [2.56 (6 and 2.63 (7 Å] involving two bromide anions, two cations and two water molecules.

  1. Friction anisotropy in boronated graphite

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, N., E-mail: niranjan@igcar.gov.in [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam (India); Radhika, R. [Crystal Growth Centre, Anna University, Chennai (India); Kozakov, A.T. [Research Institute of Physics, Southern Federal University, Rostov-on-Don (Russian Federation); Pandian, R. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam (India); Chakravarty, S. [UGC-DAE CSR, Kalpakkam (India); Ravindran, T.R.; Dash, S.; Tyagi, A.K. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam (India)

    2015-01-01

    Graphical abstract: - Highlights: • Friction anisotropy in boronated graphite is observed in macroscopic sliding condition. • Low friction coefficient is observed in basal plane and becomes high in prismatic direction. • 3D phase of boronated graphite transformed into 2D structure after friction test. • Chemical activity is high in prismatic plane forming strong bonds between the sliding interfaces. - Abstract: Anisotropic friction behavior in macroscopic scale was observed in boronated graphite. Depending upon sliding speed and normal loads, this value was found to be in the range 0.1–0.35 in the direction of basal plane and becomes high 0.2–0.8 in prismatic face. Grazing-incidence X-ray diffraction analysis shows prominent reflection of (0 0 2) plane at basal and prismatic directions of boronated graphite. However, in both the wear tracks (1 1 0) plane become prominent and this transformation is induced by frictional energy. The structural transformation in wear tracks is supported by micro-Raman analysis which revealed that 3D phase of boronated graphite converted into a disordered 2D lattice structure. Thus, the structural aspect of disorder is similar in both the wear tracks and graphite transfer layers. Therefore, the crystallographic aspect is not adequate to explain anisotropic friction behavior. Results of X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy shows weak signature of oxygen complexes and functional groups in wear track of basal plane while these species dominate in prismatic direction. Abundance of these functional groups in prismatic plane indicates availability of chemically active sites tends to forming strong bonds between the sliding interfaces which eventually increases friction coefficient.

  2. Friction anisotropy in boronated graphite

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Friction anisotropy in boronated graphite is observed in macroscopic sliding condition. • Low friction coefficient is observed in basal plane and becomes high in prismatic direction. • 3D phase of boronated graphite transformed into 2D structure after friction test. • Chemical activity is high in prismatic plane forming strong bonds between the sliding interfaces. - Abstract: Anisotropic friction behavior in macroscopic scale was observed in boronated graphite. Depending upon sliding speed and normal loads, this value was found to be in the range 0.1–0.35 in the direction of basal plane and becomes high 0.2–0.8 in prismatic face. Grazing-incidence X-ray diffraction analysis shows prominent reflection of (0 0 2) plane at basal and prismatic directions of boronated graphite. However, in both the wear tracks (1 1 0) plane become prominent and this transformation is induced by frictional energy. The structural transformation in wear tracks is supported by micro-Raman analysis which revealed that 3D phase of boronated graphite converted into a disordered 2D lattice structure. Thus, the structural aspect of disorder is similar in both the wear tracks and graphite transfer layers. Therefore, the crystallographic aspect is not adequate to explain anisotropic friction behavior. Results of X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy shows weak signature of oxygen complexes and functional groups in wear track of basal plane while these species dominate in prismatic direction. Abundance of these functional groups in prismatic plane indicates availability of chemically active sites tends to forming strong bonds between the sliding interfaces which eventually increases friction coefficient

  3. Use of 82Br and 131I radionuclides in studies of goitrogenic effects of exogenous bromide

    International Nuclear Information System (INIS)

    The interference of excessive bromide intake with iodine metabolism in the rat was studied using 82Br and 131I radionuclides. Mainly lactating rat dams and their pups were used, in addition to adult male rats, in the present studies. Particularly, the influence of high bromide intake in lactating rat dams on the transfer of iodine and bromide to suckling young through breast milk was evaluated. The induction of hypothyroid status in the pups by high bromide intake in the mothers was proved unambiguously. Excessive bromide in lactating rat dams caused a marked decrease in plasma levels of thyroid hormones both, in the mothers and in their sucklings. The effects of an enhanced bromide intake on the thyroid function in relation to iodine status in the animals were also followed. Marked goitrogenic and thyrotoxic effects of excessive bromide in adult rats were significantly enhanced under the conditions of simultaneous iodine deficiency in the experimental animals. (author)

  4. Very long terahertz free induction decay in gaseous hydrogen bromide

    International Nuclear Information System (INIS)

    Free induction decay radiation was observed in low pressure hydrogen bromide that continued for more than 180 ns after excitation by a terahertz pulse from a free electron laser. The signal was measured in real time using an ultrafast Schottky diode detector. Such a signal corresponds in frequency domain spectral resolution to about 10 MHz, which allows for resolution of the isotopic and quadrupole structure of the absorption line. (letter)

  5. Thyrotoxic effects of exogenous bromide in the rat

    Czech Academy of Sciences Publication Activity Database

    Pavelka, Stanislav

    Bratislava: Slovak University of Technology, 2008 - (Manová, A.; Čacho, F.), s. 173-174 ISSN 1335-3160. [Priemyselná toxikológia 08 /28./. Tatranská Štrba (SK), 18.06.2008-20.06.2008] Grant ostatní: GA AV ČR(CZ) KJB401630701; MYORES(XE) 511978 Institutional research plan: CEZ:AV0Z50110509 Keywords : thyroid gland * bromide * rat Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition

  6. High-speed Laser Micromachining with Copper Bromide Laser

    CERN Document Server

    Balchev, I I; Minkovski, N I; Sabotinov, N V; Balchev, Ivaylo I.; Kostadinov, Ivan K.; Minkovski, Nikolai I.; Sabotinov, Nikola V.

    2006-01-01

    The application of the copper bromide (CuBr) laser as an attractive tool in the micro-machining of different materials has been demonstrated. High-quality drilling by trepanning and precision cutting was established on several materials with a negligible heat-affected zone (HAZ). That good performance was a result of the combination of high power visible radiation, short pulses, and close to the diffraction-limited laser beam quality with high-speed galvo scanner beam steering.

  7. Criticality in aqueous solutions of 3-methylpyridine and sodium bromide.

    Science.gov (United States)

    Kostko, A F; Anisimov, M A; Sengers, J V

    2004-08-01

    We address a controversial issue regarding the nature of critical behavior in ternary electrolyte solutions of water, 3-methylpyridine, and sodium bromide. Earlier light-scattering studies showed an anomalous critical behavior in this system that was attributed to the formation of a microheterogeneous phase associated with ion-molecule clustering [M.A. Anisimov, J. Jacob, A. Kumar, V.A. Agayan, and J. V. Sengers, Phys. Rev. Lett. 85, 2336 (2000)

  8. ELECTROCHEMICAL REDUCTION OF DODECYLPYRIDINIUM BROMIDE IN APROTIC SOLVENTS: MECHANISTIC STUDIES

    Czech Academy of Sciences Publication Activity Database

    Hromadová, Magdaléna; Pospíšil, Lubomír; Sokolová, Romana; Kolivoška, Viliam

    2011-01-01

    Roč. 76, č. 12 (2011), s. 1895-1908. ISSN 0010-0765 R&D Projects: GA AV ČR IAA400400802; GA ČR GA203/08/1157; GA ČR GA203/09/0705; GA MŠk(CZ) MEB041006 Institutional research plan: CEZ:AV0Z40400503 Keywords : spectroelectrochemistry * dodecylpyridinium bromide * mechanistic studies Subject RIV: CG - Electrochemistry Impact factor: 1.283, year: 2011

  9. 4-Hydroxy-1,2,6-trimethylpyridinium bromide monohydrate

    Directory of Open Access Journals (Sweden)

    T. Seethalakshmi

    2013-06-01

    Full Text Available The title salt, C8H12NO+·Br−·H2O, is isomorphous with the chloride analogue [Seethalakshmi et al. (2013. Acta Cryst. E69, o835–o836]. In the solid state, the cations, anions and water molecules are interlinked by a network of O—H...O, O—H...Br and C—H...Br interactions. The water molecule makes two O—H...Br hydrogen bonds, generating [010] zigzag chains of alternating water molecules and bromide anions. The cation is involved in two intermolecular C—H...Cl interactions in the chloride salt, whereas three intermolecular C—H...Br interactions are observed in the title bromide salt. This additional intermolecular C—H...Br interaction links the adjacent water and bromide zigzag chains via cationic molecules. In addition, weak π–π stacking interactions are observed between pyridinium rings [centroid–centroid distance = 3.5664 (13 Å].

  10. Structural, vibrational and theoretical studies of L-histidine bromide

    Science.gov (United States)

    Ahmed, A. Ben; Feki, H.; Abid, Y.; Boughzala, H.; Mlayah, A.

    2008-10-01

    This paper presents the results of our calculations of the geometric parameters, vibrational spectra and hyperpolarizability of a non linear optical material, L-histidine bromide. Due to the lack of sufficiently precise information on the geometric structure available in literature, theoretical calculations were preceded by re-determination of the crystal X-ray structure. Single crystals of L-histidine bromide have been grown by slow evaporation of an aqueous solution at room temperature. The compound crystallizes in the non-Centro symmetric space group P2 12 12 1 of the orthorhombic system. Raman spectra have been recorded in the range [200-3500 cm -1]. All observed vibrational bands have been discussed and assigned to normal mode or to combinations and overtones on the basis of our calculations. The optimized geometric bond lengths and bond angles obtained by using HF and DFT (B3LYP and BLYP) show good agreement with the experimental data. Comparison between the measured and the calculated vibrational frequencies indicate that B3LYP is superior to the scaled HF approach for molecular vibrational problems. To investigate microscopic second order non linear optical properties of L-histidine bromide, the electric dipole μ, the polarizability α and the hyperpolarizability β were computed using DFT//B3LYP/6-31G(d) method. According to our calculations, the title compound exhibits non-zero β value revealing microscopic second order NLO behaviour.

  11. L-Tryptophan L-tryptophanium bromide: Anhydrous and monohydrate

    Science.gov (United States)

    Ghazaryan, V. V.; Giester, G.; Fleck, M.; Petrosyan, A. M.

    2015-12-01

    L-Tryptophan L-tryptophanium bromide (I) and L-tryptophan L-tryptophanium bromide monohydrate (II) are new salts with (A⋯A+) type dimeric cation. The salt (I) crystallizes in the monoclinic system (space group P21, Z = 2) and is isostructural with respective chloride (V.V. Ghazaryan et al., Spectrochim. Acta A 136(2015) 743-750), while the salt (II) was obtained previously (T. Takigawa et al., Bull. Chem. Soc. Jap. 39(1966) 2369-2378) and described as hemyhydrate without structure determination. The salt (II) crystallizes in orthorhombic system (space group P212121, Z = 4). The dimeric cations in (I) and (II) are formed by O-H⋯O hydrogen bonds with the O⋯O distances equal to 2.538(3) Å and 2.481(3) Å respectively. The infrared and Raman spectra of the crystals are studied and compared with the spectra of L-tryptophan L-tryptophanium chloride and L-tryptophanium bromide.

  12. Palladium-catalyzed thiocarbonylation of aryl, vinyl, and benzyl bromides.

    Science.gov (United States)

    Burhardt, Mia N; Ahlburg, Andreas; Skrydstrup, Troels

    2014-12-19

    A catalytic protocol for synthesis of thioesters from aryl, vinyl, and benzyl bromides as well as benzyl chlorides was developed using only stoichiometric amounts of carbon monoxide, produced from a solid CO precursor inside a two-chamber system. As a catalytic system, the combination of bis(benzonitrile) palladium(II) chloride and Xantphos furnished the highest yields of the desired compounds, along with the weak base, NaOAc, in anisole at 120 °C. The choice of catalytic system as well as solvent turned out to be important in order to ensure a high chemoselectivity in the reaction. Both electron-rich and electron-deficient aryl bromides worked well in this reaction. Addition of 1 equiv of sodium iodide to the reaction improved the chemoselectivity with the electron-deficient aryl bromides. The thiol scope included both aryl and alkyl thiols, including 2-mercaptobenzophenones, whereby a thiocarbonylation followed by a subsequent McMurry coupling yielded differently substituted benzothiophenes. It was demonstrated that the methodology could be applied for (13)C introduction into the thiophene ring. PMID:24919457

  13. Synthesis of boron nitride nanotubes by boron ink annealing.

    Science.gov (United States)

    Li, Lu Hua; Chen, Ying; Glushenkov, Alexey M

    2010-03-12

    Ball-milling and annealing is one effective method for the mass production of boron nitride nanotubes (BNNTs). We report that the method has been modified to a boron (B) ink annealing method. In this new process, the nanosize ball-milled B particles are mixed with metal nitrate in ethanol to form an ink-like solution, and then the ink is annealed in nitrogen-containing gas to form nanotubes. The new method greatly enhances the yield of BNNTs, giving a higher density of nanotubes. These improvements are caused by the addition of metal nitrate and ethanol, both of which can strongly boost the nitriding reaction, as revealed by thermogravimetric analysis. The size and structure of BNNTs can be controlled by varying the annealing conditions. This high-yield production of BNNTs in large quantities enables the large-scale application of BNNTs. PMID:20154372

  14. Synthesis of boron nitride nanotubes by boron ink annealing

    International Nuclear Information System (INIS)

    Ball-milling and annealing is one effective method for the mass production of boron nitride nanotubes (BNNTs). We report that the method has been modified to a boron (B) ink annealing method. In this new process, the nanosize ball-milled B particles are mixed with metal nitrate in ethanol to form an ink-like solution, and then the ink is annealed in nitrogen-containing gas to form nanotubes. The new method greatly enhances the yield of BNNTs, giving a higher density of nanotubes. These improvements are caused by the addition of metal nitrate and ethanol, both of which can strongly boost the nitriding reaction, as revealed by thermogravimetric analysis. The size and structure of BNNTs can be controlled by varying the annealing conditions. This high-yield production of BNNTs in large quantities enables the large-scale application of BNNTs.

  15. High bromide intake in the lactating rat significantly influences transfer of iodine and bromide via mother's milk

    Czech Academy of Sciences Publication Activity Database

    Pavelka, Stanislav

    Brno : Masarykova univerzita, 2007. s. 13-14. ISBN 80-120-3942-6. [Pracovní setkání biochemiků a molekulárních biologů /10./. 08.02.2006-09.02.2006, Brno] Institutional research plan: CEZ:AV0Z50110509 Keywords : spr2 * bromide * iodine * rat Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition

  16. High bromide intake in the lactating rat significantly influences transfer of iodine and bromide via mother's milk

    Czech Academy of Sciences Publication Activity Database

    Pavelka, Stanislav

    Brno : Masarykova univerzita v Brně, 2006 - (Wimmerová, M.; Beneš, P.). s. 13-14 ISBN 80-210-3942-6. [Pracovní setkání biochemiků a molekulárních biologů /10./. 08.02.2006-09.02.2006, Brno] Institutional research plan: CEZ:AV0Z50110509 Keywords : bromide * iodine * mother's milk Subject RIV: ED - Physiology

  17. Solid miscibility of common-anion lithium and sodium halides. Experimental determination of the region of demixing in lithium bromide + sodium bromide

    NARCIS (Netherlands)

    Oonk, H.A.J.; Wijk, H.J. van; Doornhof, D.

    1984-01-01

    The region of demixing of solid lithium bromide + sodium bromide mixtures has been measured by X-ray diffraction. The critical temperature of mixing corresponding to a thermodynamic fit of the experimental data is 513 K. Estimates are given of the regions of demixing in solid lithium chloride + sodi

  18. Synthesis of vinyl boronates from aldehydes by a practical boron-Wittig reaction.

    Science.gov (United States)

    Coombs, John R; Zhang, Liang; Morken, James P

    2015-04-01

    A highly stereoselective boron-Wittig reaction between stable and readily accessible 1,1-bis(pinacolboronates) and aldehydes furnishes a variety of synthetically useful di- and trisubstituted vinyl boronate esters. PMID:25799147

  19. Synthesis of Boron Nanowires, Nanotubes, and Nanosheets

    Directory of Open Access Journals (Sweden)

    Rajen B. Patel

    2015-01-01

    Full Text Available The synthesis of boron nanowires, nanotubes, and nanosheets using a thermal vapor deposition process is reported. This work confirms previous research and provides a new method capable of synthesizing boron nanomaterials. The materials were made by using various combinations of MgB2, Mg(BH42, MCM-41, NiB, and Fe wire. Unlike previously reported methods, a nanoparticle catalyst and a silicate substrate are not required for synthesis. Two types of boron nanowires, boron nanotubes, and boron nanosheets were made. Their morphology and chemical composition were determined through the use of scanning electron microscopy, transmission electron microscopy, and electron energy loss spectroscopy. These boron-based materials have potential for electronic and hydrogen storage applications.

  20. Analysis of magnetron sputtered boron oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Buc, Dalibor [Slovak University of Technology in Bratislava (Slovakia); Bello, Igor [City University of Hong Kong, Kowloon, Hong Kong (China); Caplovicova, Maria [Comenius University in Bratislava (Slovakia); Mikula, Milan; Kovac, Jaroslav; Hotovy, Ivan [Slovak University of Technology in Bratislava (Slovakia); Chong, Yat Min [City University of Hong Kong, Kowloon, Hong Kong (China); Siu, Guei Gu [City University of Hong Kong, Kowloon, Hong Kong (China)], E-mail: apggsiu@cityu.edu.hk

    2007-10-15

    Boron oxide films were grown on silicon substrates by radio-frequency (rf) unbalanced magnetron sputtering of a boron target in argon-oxygen gas mixtures with different compositions. Microscopic analyses show that overall boron oxide films are amorphous. The film prepared at oxygen/argon flow rate ratio > 0.05 developed large crystallites of boric acid in localize areas of amorphous boron oxide matrices. These crystallites were unstable and at electron microscopic analysis they continuously transformed to a cubic HBO{sub 2} phase and then completely vanished leaving an underlying amorphous boron oxide film behind. The analyses indicate the coexistence of B{sub 6}O, HBO{sub 2} crystallites and amorphous boron oxide matrices. Fourier transform infrared (FTIR) spectra revealed spectral bands of BOH, BO, BOB and BH groups. Nanohardness and elastic modulus of a film prepared at low oxygen concentration approach 30 and 300 GPa, respectively. These parameters however vary with deposition conditions.

  1. Microwave sintering of boron carbide composites

    International Nuclear Information System (INIS)

    Boron carbide is an important ceramic material because of its high hardness and low specific gravity. it is used for applications involving impact and wear resistance. The disadvantages of boron carbide materials are difficulty in fabrication and sensitivity to brittle fracture. These problems are significantly reduced by production of cermets based on boron carbide and aluminum or aluminum alloys. Microwave heating of boron carbide materials results in ultrarapid heating and high temperatures. Therefore, a finer microstructure is obtained. The objective of this work was to define a technology that would allow the manufacture of boron carbide ceramics having mechanical properties similar to those exhibited by hot-pressed specimens. microwave heating would be used for the densification step. Mixtures of boron carbide and aluminum were considered for this research because aluminum simultaneously acts as a sintering aid and introduces phases that contribute to toughness enhancement

  2. Prediction of boron carbon nitrogen phase diagram

    Science.gov (United States)

    Yao, Sanxi; Zhang, Hantao; Widom, Michael

    We studied the phase diagram of boron, carbon and nitrogen, including the boron-carbon and boron-nitrogen binaries and the boron-carbon-nitrogen ternary. Based on the idea of electron counting and using a technique of mixing similar primitive cells, we constructed many ''electron precise'' structures. First principles calculation is performed on these structures, with either zero or high pressures. For the BN binary, our calculation confirms that a rhmobohedral phase can be stablized at high pressure, consistent with some experimental results. For the BCN ternary, a new ground state structure is discovered and an Ising-like phase transition is suggested. Moreover, we modeled BCN ternary phase diagram and show continuous solubility from boron carbide to the boron subnitride phase.

  3. CVD-produced boron filaments

    Science.gov (United States)

    Wawner, F. E.; Debolt, H. E.; Suplinskas, R. D.

    1980-01-01

    A technique for producing boron filaments with an average tensile strength of 6.89 GPa has been developed which involves longitudinal splitting of the filament and core (substrate) removal by etching. Splitting is accomplished by a pinch wheel device which continuously splits filaments in lengths of 3.0 m by applying a force to the side of the filament to create a crack which is then propagated along the axis by a gentle sliding action. To facilitate the splitting, a single 10 mil tungsten substrate is used instead of the usual 0.5 mil substrate. A solution of hot 30% hydrogen peroxide is used to remove the core without attacking the boron. An alternative technique is to alter the residual stress by heavily etching the filament. Average strengths in the 4.83-5.52 GPa range have been obtained by etching an 8 mil filament to 4 mil.

  4. Boron clusters in luminescent materials.

    Science.gov (United States)

    Mukherjee, Sanjoy; Thilagar, Pakkirisamy

    2016-01-21

    In recent times, luminescent materials with tunable emission properties have found applications in almost all aspects of modern material sciences. Any discussion on the recent developments in luminescent materials would be incomplete if one does not account for the versatile photophysical features of boron containing compounds. Apart from triarylboranes and tetra-coordinate borate dyes, luminescent materials consisting of boron clusters have also found immense interest in recent times. Recent studies have unveiled the opportunities hidden within boranes, carboranes and metalloboranes, etc. as active constituents of luminescent materials. From simple illustrations of luminescence, to advanced applications in LASERs, OLEDs and bioimaging, etc., the unique features of such compounds and their promising versatility have already been established. In this review, recent revelations about the excellent photophysical properties of such materials are discussed. PMID:26574714

  5. Conduction mechanism in boron carbide

    Science.gov (United States)

    Wood, C.; Emin, D.

    1984-01-01

    Electrical conductivity, Seebeck-coefficient, and Hall-effect measurements have been made on single-phase boron carbides, B(1-x)C(x), in the compositional range from 0.1 to 0.2 X, and between room temperature and 1273 K. The results indicate that the predominant conduction mechanism is small-polaron hopping between carbon atoms at geometrically inequivalent sites.

  6. Sintering behavior of boron carbide

    International Nuclear Information System (INIS)

    Pressureless sintering behavior of boron carbide (B4C) in argon was studied, with change in time and temperature, using carbon as sintering aid. Carbon was added via fenolic resin, acting also as a binder. After isostatic pressing the specimens were sintered in a graphite furnace at 19600C/1h, 21600C/15 minutes and 1h and 22000C/1h. The achieved density was 97% of the theoretical. Some mechanical properties and microstructural aspects have been evaluated. (author)

  7. Boron Enrichment in Martian Clay

    OpenAIRE

    James D Stephenson; Lydia J Hallis; Kazuhide Nagashima; Freeland, Stephen J.

    2013-01-01

    We have detected a concentration of boron in martian clay far in excess of that in any previously reported extra-terrestrial object. This enrichment indicates that the chemistry necessary for the formation of ribose, a key component of RNA, could have existed on Mars since the formation of early clay deposits, contemporary to the emergence of life on Earth. Given the greater similarity of Earth and Mars early in their geological history, and the extensive disruption of Earth's earliest minera...

  8. Boron removal from geothermal waters by electrocoagulation

    International Nuclear Information System (INIS)

    Most of the geothermal waters in Turkey contain extremely high concentration of boron when they are used for irrigation. The use of geothermal waters for irrigation can results in excess amount deposition of boron in soil. On the other hand, a minimal boron concentration is required for irrigational waters. In this study, electrocoagulation (EC) was selected as a treatment process for the removal of boron from thermal waters obtained from Ilica-Erzurum in Turkey. Current density (CD), pH of solution and temperature of solution were selected as operational parameters. The results showed that boron removal efficiency increased from pH 4.0 to 8.0 and decreased at pH 10.0. Although boron removal efficiency was highest at pH 8.0, energy consumption was very high at this pH value compared to other pH intervals. Boron removal efficiency reached to 95% with increasing current density from 1.5 to 6.0 mA/cm2, but energy consumption was also increased in this interval. At higher temperatures of solution, such as 313 and 333 K, boron removal efficiency increased. At optimum conditions, boron removal efficiency in geothermal water reached up to 95%

  9. Boron removal from geothermal waters by electrocoagulation

    Energy Technology Data Exchange (ETDEWEB)

    Yilmaz, A. Erdem [Atatuerk University, Faculty of Engineering, Department of Environmental Engineering., 25240 Erzurum (Turkey)], E-mail: aerdemy@atauni.edu.tr; Boncukcuoglu, Recep [Atatuerk University, Faculty of Engineering, Department of Environmental Engineering., 25240 Erzurum (Turkey); Kocakerim, M. Muhtar [Atatuerk University, Faculty of Engineering, Department of Chemical Engineering, 25240 Erzurum (Turkey); Yilmaz, M. Tolga; Paluluoglu, Cihan [Atatuerk University, Faculty of Engineering, Department of Environmental Engineering., 25240 Erzurum (Turkey)

    2008-05-01

    Most of the geothermal waters in Turkey contain extremely high concentration of boron when they are used for irrigation. The use of geothermal waters for irrigation can results in excess amount deposition of boron in soil. On the other hand, a minimal boron concentration is required for irrigational waters. In this study, electrocoagulation (EC) was selected as a treatment process for the removal of boron from thermal waters obtained from Ilica-Erzurum in Turkey. Current density (CD), pH of solution and temperature of solution were selected as operational parameters. The results showed that boron removal efficiency increased from pH 4.0 to 8.0 and decreased at pH 10.0. Although boron removal efficiency was highest at pH 8.0, energy consumption was very high at this pH value compared to other pH intervals. Boron removal efficiency reached to 95% with increasing current density from 1.5 to 6.0 mA/cm{sup 2}, but energy consumption was also increased in this interval. At higher temperatures of solution, such as 313 and 333 K, boron removal efficiency increased. At optimum conditions, boron removal efficiency in geothermal water reached up to 95%.

  10. Boron deposition from fused salts. Final report

    International Nuclear Information System (INIS)

    A partial evaluation of the feasibility of a process to electrodeposit pure coherent coatings of elemental boron from molten fluorides has been performed. The deposit produced was powdery and acicular, unless the fluoride melt was purified to have very low oxygen concentration. When the oxygen activity was reduced in the melt by addition of crystalline elemental boron, dense, amorphous boron deposit was produced. The boron deposits produced had cracks but were otherwise pure and dense and ranged up to 0.35 mm thick. Information derived during this project suggests that similar deposits might be obtained crack-free up to 1.00 mm thick by process modifications and improvements

  11. Automated determination of bromide in waters by ion chromatography with an amperometric detector

    Science.gov (United States)

    Pyen, G.S.; Erdmann, D.E.

    1983-01-01

    An automated ion chromatograph, including a program controller, an automatic sampler, an integrator, and an amperometric detector, was used to develop a procedure for the determination of bromide in rain water and many ground waters. Approximately 10 min is required to obtain a chromatogram. The detection limit for bromide is 0.01 mg l-1 and the relative standard deivation is <5% for bromide concentrations between 0.05 and 0.5 mg l-1. Chloride interferes if the chloride-to-bromide ratio is greater than 1 000:1 for a range of 0.01-0.1 mg l-1 bromide; similarly, chloride interferes in the 0.1-1.0 mg l-1 range if the ratio is greater than 5 000:1. In the latter case, a maximum of 2 000 mg l-1 of chloride can be tolerated. Recoveries of known concentrations of bromide added to several samples, ranged from 97 to 110%. ?? 1983.

  12. A study of bromide in the Mandovi-Zuari river system of Goa

    Science.gov (United States)

    de Souza, Francisca P.; Dalal, V. N. Kamat

    1985-10-01

    Bromide was the subject of detailed investigation in the Mandovi-Zuari river system and information was compiled on its spatial and temporal distribution. A simple mixture relation of Carpenter et al. was applied and seawater percentage and bromide concentrations were computed. The variation of bromide with chlorinity was linear indicating the purely conservative character of bromide and its seawater origin. Seawater ranged between 1 and 3% in monsoon, 76 and 91% in post-monsoon and 92 and 97% in pre-monsoon in the Mandovi-Zuari river system. As the bromide concentration varied linearly with chlorinity both longitudinally and depthwise, it followed that bromide exhibited a simple distribution pattern established by conservative mixing.

  13. Enzyme activities in agricultural soils fumigated with methyl bromide alternatives

    OpenAIRE

    Klose, Susanne; Ajwa, H A

    2004-01-01

    Pre-plant fumigation of agricultural soils with a combination of methyl bromide (MeBr) and chloropicrin (CP) to control nematodes, soil-borne pathogens and weeds has been a common practice in strawberry (Fragaria X ananassa Duchesne) production since the 1960s. MeBr will be phased out by 2005, but little is known about the impacts of alternative fumigants on soil microbial processes. We investigated the response of microbial biomass and enzyme activities in soils fumigated over two years with...

  14. On the complexing of certain transition metal bromides with trimecaine

    International Nuclear Information System (INIS)

    Synthesis and IR spectroscopy of the structure of cadmium bromide coordination compounds and certain other elements with trimecaine (diethylamino-2,4-6-trymethylacetanilidine, L) are carried out. Complexes of the CdLBr2(1) and Cd(LH)2Br4(2) composition are prepared, this molecular structure is established. In complex 1 cadmium atom is shown to be coordinately related to the nitrogen atom of the ternary aminogroup; in complex 2 the bond between the CdBr42- anion and ternary nitrogen atom of the ligand is of the ionic character

  15. Interaction between gaseous ozone and crystalline potassium bromide

    Science.gov (United States)

    Levanov, A. V.; Maksimov, I. B.; Isaikina, O. Ya.; Antipenko, E. E.; Lunin, V. V.

    2016-07-01

    The formation of nonvolatile products of the oxidation of a bromide ion during the interaction between gaseous ozone and powdered crystalline KBr is studied. It is found that potassium bromate KBrO3 is the main product of the reaction. The influence of major experimental factors (the duration of ozonation, the concentration of ozone, the humidity of the initial gas, and the temperature) on the rate of formation of bromate is studied. The effective constants of the formation of bromate during the interaction between O3 and Br- in a heterogeneous gas-solid body system and in a homogeneous aqueous solution are compared.

  16. Suicide by intravenous injection of rocuronium-bromide: Case report

    Directory of Open Access Journals (Sweden)

    Nikolić Slobodan

    2005-01-01

    Full Text Available Suicides by intravenous injection of an overdose of medicaments are uncommon. In this paper, we present the case of a suicide by rocuronium-bromide injection in combination with an oral overdose of metoprolol. Unfortunately, in Belgrade, there is no toxicological laboratory capable of detecting rocuronium. The interpretation of autopsy and toxicological data in this case was made difficult due to the extreme putrefaction of the body of the deceased. So, by forensic investigation, the case was solved indirectly, through circumstantial evidence: an empty ampoule of rocuronium found near the body, as well as a plastic syringe and cloth-bandage found in the left hand of the deceased.

  17. Bacterial Oxidation of Methyl Bromide in Fumigated Agricultural Soils

    OpenAIRE

    Miller, L. G.; Connell, T. L.; Guidetti, J. R.; Oremland, R. S.

    1997-01-01

    The oxidation of [(sup14)C]methyl bromide ([(sup14)C]MeBr) to (sup14)CO(inf2) was measured in field experiments with soils collected from two strawberry plots fumigated with mixtures of MeBr and chloropicrin (CCl(inf3)NO(inf2)). Although these fumigants are considered potent biocides, we found that the highest rates of MeBr oxidation occurred 1 to 2 days after injection when the fields were tarped, rather than before or several days after injection. No oxidation of MeBr occurred in heat-kille...

  18. Methyl bromide: Ocean sources, ocean sinks, and climate sensitivity

    OpenAIRE

    A. D. Anbar; Yung, Y. L.; Chavez, F.P.

    1996-01-01

    The oceans play an important role in the geochemical cycle of methyl bromide (CH_3Br), the major carrier of O_3-destroying bromine to the stratosphere. The quantity of CH_3Br produced annually in seawater is comparable to the amount entering the atmosphere each year from natural and anthropogenic sources. The production mechanism is unknown but may be biological. Most of this CH_3Br is consumed in situ by hydrolysis or reaction with chloride. The size of the fraction which escapes to the atmo...

  19. Method for determination of boron carbide in wurtzite-like boron nitride

    International Nuclear Information System (INIS)

    A technique for increase of sensitivity and analysis accuracy while boron carbide determination in wurtzite-like boron nitride is proposed. Boron nitride with an addition of boron carbide is bjected to treatment by the mixture of concentrated sulphuric acid and 0.1-0.5 N of porassium bichromate solution at ratio of (2-1):1 at the temperature of mixture boiling. Boron carboide content is calculated according to the quantity of restored Cr(3+), which is determined by titration of Cr(6+) excess with the Mohr's salt solution

  20. Boron coating on boron nitride coated nuclear fuels by chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Durmazucar, Hasan H.; Guenduez, Guengoer E-mail: ggunduz@metu.edu.tr

    2000-12-01

    Uranium dioxide-only and uranium dioxide-gadolinium oxide (5% and 10%) ceramic nuclear fuel pellets which were already coated with boron nitride were coated with thin boron layer by chemical vapor deposition to increase the burn-up efficiency of the fuel during reactor operation. Coating was accomplished from the reaction of boron trichloride with hydrogen at 1250 K in a tube furnace, and then sintering at 1400 and 1525 K. The deposited boron was identified by infrared spectrum. The morphology of the coating was studied by using scanning electron microscope. The plate, grainy and string (fiber)-like boron structures were observed.

  1. Boron coating on boron nitride coated nuclear fuels by chemical vapor deposition

    International Nuclear Information System (INIS)

    Uranium dioxide-only and uranium dioxide-gadolinium oxide (5% and 10%) ceramic nuclear fuel pellets which were already coated with boron nitride were coated with thin boron layer by chemical vapor deposition to increase the burn-up efficiency of the fuel during reactor operation. Coating was accomplished from the reaction of boron trichloride with hydrogen at 1250 K in a tube furnace, and then sintering at 1400 and 1525 K. The deposited boron was identified by infrared spectrum. The morphology of the coating was studied by using scanning electron microscope. The plate, grainy and string (fiber)-like boron structures were observed

  2. Some physical properties of compacted specimens of highly dispersed boron carbide and boron suboxide

    International Nuclear Information System (INIS)

    Structure, shear modulus and internal friction (IF) of compacted specimens of boron carbide and boron suboxide have been investigated. Microtwins and stacking faults were observed along the {100} plane systems of polycrystalline specimens of boron carbide. Electrical conductivity of the specimens was that of p-type. Concentration of holes varied from 1017 to 1019 cm-3. The IF was measured in the temperature range 80-300 K. It was shown that the IF of boron carbide and that of boron suboxide were characterized with a set of similar relaxation processes. Mechanisms of the relaxation processes in boron carbide and boron suboxide are discussed in terms of the Hasiguti model of interaction between dislocations and point defects

  3. Boron carbide synthesis by carbothermic reduction of boron oxide

    International Nuclear Information System (INIS)

    Boron carbide (B4C) is a ceramic material of technological applications due to its extreme hardness and high chemical as well as thermal stability. Some parameters of the process for obtaining B4C by carbothermic reduction of B2O3 have been determined. The starting powders and the final products have been analysed by chemical, spectrographic and X-ray diffraction methods. The results show that the B4C obtained by the carbothermic reduction process is suitable for applications with a definite determination of the free carbon content. (author)

  4. Modeling water/lithium bromide absorption chillers in ASPEN Plus

    International Nuclear Information System (INIS)

    Highlights: → Single- and double-effect water/lithium bromide absorption chiller designs are numerically modeled using ASPEN. → The modeling procedure is described and the results are compared to published modeling data to access prediction accuracy. → Predictions for the single- and double-effect designs are within 3% and 5%, respectively of published data for all cycle parameters of interest. → The absorption cycle models presented allow investigation of using absorption chillers for waste heat utilization in the oil and gas industry. -- Abstract: Absorption chillers are a viable option for providing waste heat-powered cooling or refrigeration in oil and gas processing plants, thereby improving energy efficiency. In this paper, single- and double-effect water/lithium bromide absorption chiller designs are numerically modeled using ASPEN. The modeling procedure is described and the results are compared to published modeling data to access prediction accuracy. Predictions for the single- and double-effect designs are within 3% and 5%, respectively of published data for all cycle parameters of interest. The absorption cycle models presented not only allow investigation into the benefits of using absorption chillers for waste heat utilization in the oil and gas industry, but are also generically applicable to a wide range of other applications.

  5. Development of copper bromide laser master oscillator power amplifier system

    Indian Academy of Sciences (India)

    G N Tiwari; R K Mishra; R Khare; S V Nakhe

    2014-02-01

    Development of master oscillator power amplifier (MOPA) system of copper bromide laser (CBL) operating at 110 W average power is reported. The spectral distribution of power at green (510.6 nm) and yellow (578.2 nm) components in the output of a copper bromide laser is studied as a function of operating parameters. The electrical input power was varied from 2.6 to 4.3 kW, the pulse repetition frequency (PRF) was changed from 16 to 19 kHz, and the pressure of the buffer gas (neon) was kept fixed at 20 mbar. When the electrical input power was increased to 4.3 kW from 2.6 kW, the tube-wall temperature also increased to 488°C from 426°C but the ratio of the green to yellow power decreased to 1.53 from 3.73. The ratio of green to yellow power decreased to 1.53 from 1.63 when the PRF of the laser was increased to 19 kHz from 16 kHz. These observations are explained in terms of electron temperature, energy levels of transitions, and voltage and current waveforms across the laser head.

  6. Synthesis and Characterization of Mercuric Bromide-Phenothiazine Complexes

    Directory of Open Access Journals (Sweden)

    Vidisha A. Alwani

    2014-12-01

    Full Text Available N-alkylphenothiazines (NAPTZs are biologically active heterocyclic compounds that find extensive applications in the field of medicine. In the pharmaceutical industry, they are used as psychotherapeutic, antiemetic, and antihistaminic drugs. In this study, complexation reactions of mercuric bromide with NAPTZs as principal ligands have been investigated in MeOH medium. Five mercuric bromide complexes of the NAPTZ ligands namely, chlorpromazine hydrochloride (CP.HCl, promethazine hydrochloride (PM.HCl, ethopropazine hydrochloride (EP.HCl, trifluoperazine dihydrochloride (TF.2HCl and thioridazine hydrochloride (TR.HCl have been synthesized. These complexes were subjected to elemental analysis, solubility, molar conductance and magnetic susceptibility, U.V-Vis, I.R, and NMR spectroscopy. The molecular formulations of the complexes have been found to be: [HgBr2(CP2].4H2O; [HgBr2(PM2].2H2O; [HgBr2(EP2]; [HgBr2(TF2].2H2O and [HgBr2(TR2]. Tentative molecular structures have been proposed and presented.

  7. Bromoform formation in ozonated groundwater containing bromide and humic substances

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, W.J.; Amy, G.L.; Moore, C.A.; Zika, R.G.

    1986-01-01

    The effect of bromide ion, organic carbon concentration (natural aquatic humic substances), pH, and solar irradiation on the formation of bromoform in ozonated groundwater has been studied. The studies were conducted on four unique samples of groundwater taken from different regions of the Biscayne Aquifer in southern Florida. All other conditions being equal, increases in bromide ion concentrations resulted in increases in CHBr/sub 3/ formation. In three of the four samples, CHBr/sub 3/ formation decreased as the pH level increased from 5 to 9. The fourth sample exhibited an opposite trend whereby the CHBr/sub 3/ concentration increased with increasing pH. Bromoform concentration increased with increased O/sub 3/ concentration over an ozone dosage range of 3.4 to 6.7 mg/L. Ozonated samples placed in sunlight immediately after ozone addition showed a decrease in the formation of CHBr/sub 3/ presumably due to the photodecomposition of HOBr/OBr.

  8. Bromoform formation in ozonated groundwater containing bromide and humic substances

    Energy Technology Data Exchange (ETDEWEB)

    Copper, W.J. (Florida International Univ., Miami (United States)); Amy, G.L. (Univ. of Arizona, Tucson (United States)); Moore, C.A.; Zika, R.G. (Univ. of Miami, FL (United States))

    The effect of bromide ion, organic carbon concentration (natural aquatic humic substances), pH, and solar irradiation on the formation of bromoform in ozonated groundwater has been studied. The studies were conducted on four unique samples of groundwater taken from different regions of the Biscayne Aquifer in southern Florida. All other conditions being equal, increases in bromide ion concentrations resulted in increases in CHBr{sub 3} formation. In three of the four samples, CHBr{sub 3} formation decreased as the pH level increased from 5 to 9. The fourth sample exhibited an opposite trend whereby the CHBr{sub 3} concentration increased with increasing pH. Bromoform concentration increased with increased O{sub 3} concentration over an ozone dosage range of 3.4 to 6.7 mg/L. Ozonated samples placed in sunlight immediately after ozone addition showed a decrease in the formation of CHBr{sub 3}, presumably due to the photodecomposition of HOBr/OBr.

  9. Possible toxicity of boron on sugar cane

    Energy Technology Data Exchange (ETDEWEB)

    Bravo C., M.

    Analyses of necrotic and green leaf tissues from sugar cane grown in the Tambo Valley (Arequipa, Peru) have shown that the boron concentration in necrotic tissue (average 657.7 ppm) is several times higher than that in the green tissue (average 55.7 ppm). This suggests that the necrosis may be due to boron toxicity.

  10. New techniques for producing thin boron films

    International Nuclear Information System (INIS)

    A review will be presented of methods for producing thin boron films using an electron gun. Previous papers have had the problem of spattering of the boron source during the evaporation. Methods for reducing this problem will also be presented. 12 refs., 4 figs

  11. Fabrication of boron-phosphide neutron detectors

    International Nuclear Information System (INIS)

    Boron phosphide is a potentially viable candidate for high neutron flux neutron detectors. The authors have explored chemical vapor deposition methods to produce such detectors and have not been able to produce good boron phosphide coatings on silicon carbide substrates. However, semi-conducting quality films have been produced. Further testing is required

  12. Computational Evidence for the Smallest Boron Nanotube

    Institute of Scientific and Technical Information of China (English)

    Xian Jie LIN; Dong Ju ZHANG; Cheng Bu LIU

    2006-01-01

    The structure of boron nanotubes (BNTs) was found not to be limited to hexagonal pyramidal structures. Based on density functional theory calculations we provided evidence for the smallest boron nanotube, a geometrical analog of the corresponding carbon nanotube. As shown by our calculations, the smallest BNT possesses highly structural, dynamical, and thermal stability, which should be interest for attempts at its synthesis.

  13. Boron carbide whiskers produced by vapor deposition

    Science.gov (United States)

    1965-01-01

    Boron carbide whiskers have an excellent combination of properties for use as a reinforcement material. They are produced by vaporizing boron carbide powder and condensing the vapors on a substrate. Certain catalysts promote the growth rate and size of the whiskers.

  14. Boron Carbides As Thermo-electric Materials

    Science.gov (United States)

    Wood, Charles

    1988-01-01

    Report reviews recent theoretical and experimental research on thermoelectric materials. Recent work with narrow-band semiconductors demonstrated possibility of relatively high thermoelectric energy-conversion efficiencies in materials withstanding high temperatures needed to attain such efficiencies. Among promising semiconductors are boron-rich borides, especially boron carbides.

  15. Nuclear fuel management and boron carbide coating

    International Nuclear Information System (INIS)

    In recent years one way of introducing burnable absorber is to coat the fuel pellets by a thin layer of burnable absorber so called integral fuel burnable absorber (IFBA). In this method the fuel is coated with boron nitride or boron carbide. Boron has low absorption cross-section and when it exists on the surface of the fuel, it interacts with thermalized neutron. B4C is a boron compound, which can be used for coating the nuclear fuel. It has high thermal stability and withstands high pressure and temperatures. High technology product of boron carbide has different ratio of B: C. But in nuclear reactor when boron carbide is used, it must be rich with boron. In this research chemical vapor decomposition (CVD) has been using boron trichloride and carbon tetra chloride for reactant materials. The experiments were carried out at high temperatures (1050 degree Celsius, 1225 degree Celsius and 1325 degree Celsius). The coated samples were analyzed using X-Ray diffractometer (XRD), scanning electron microscopy (SEM) and will be presented in this paper. It was seen that decreasing the reaction temperature caused an increase on the quality and thickness of the coating

  16. Electroanalysis of Hydrogen Peroxide at Boron Doped Diamond Electrode Modified by Silver Nanoparticles and Haemoglobin

    International Nuclear Information System (INIS)

    The electrochemical detection of H2O2 using boron doped diamond electrode modified by silver nanoparticles and haemoglobin is reported. Silver nanoparticle obtained from electrodeposition in the presence of cetyl hexadecylthmoniom bromide (CTAB) surfactant shows the best combination of detection limit, sensitivity and reproducibility. The presence of Ag nanoparticles helps bind haemoglobin to the electrode in an active form, leading to a significantly further increase of electrode response to H2O2. Detection limits below 1 μM are achieved by a synergistic effect of both modifiers, and a good linear signal response is seen up to 8 mM. Interferences from glucose, uric acid, ascorbic acid and dopamine at typical physiological levels are shown to be negligible

  17. XPS analysis of boron doped heterofullerenes

    Energy Technology Data Exchange (ETDEWEB)

    Schnyder, B.; Koetz, R. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Muhr, H.J.; Nesper, R. [ETH Zurich, Zurich (Switzerland)

    1997-06-01

    Boron heterofullerenes were generated through arc-evaporation of doped graphite rods in a helium atmosphere. According to mass spectrometric analysis only mono-substituted fullerenes like C{sub 59}B, C{sub 69}B and higher homologues together with a large fraction of higher undoped fullerenes were extracted and enriched when pyridine was used as the solvent. XPS analysis of the extracts indicated the presence of two boron species with significantly different binding energies. One peak was assigned to borid acid. The second one corresponds to boron in the fullerene cage, which is mainly C{sub 59}B, according to the mass spectrum. This boron is in a somewhat higher oxidation state than that of ordinary boron-carbon compounds. The reported synthesis and extraction procedure opens a viable route for production of macroscopic amounts of these compounds. (author) 2 figs., 1 tab., 7 refs.

  18. Boron isotopic enrichment by displacement chromatography

    International Nuclear Information System (INIS)

    10B enriched boron is used in applications requiring high volumetric neutron absorption (absorption cross section- 3837 barn for thermal and 1 barn for 1 MeV fast neutron). It is used in fast breeder reactor (as control rod material), in neutron counter, in Boron Neutron Capture Therapy etc. Owing to very small separation factor, boron isotopic enrichment is a complex process requiring large number of separation stages. Heavy Water Board has ventured in industrial scale production of 10B enriched boron using Exchange Distillation Process as well as Ion Displacement Chromatography Process. Ion Displacement Chromatography process is used in Boron Enrichment Plant at HWP, Manuguru. It is based on isotopic exchange between borate ions (B(OH)4-) on anion exchange resin and boric acid passing through resin. The isotopic exchange takes place due to difference in zero point energy of 10B and 11B

  19. Stabilization of boron carbide via silicon doping.

    Science.gov (United States)

    Proctor, J E; Bhakhri, V; Hao, R; Prior, T J; Scheler, T; Gregoryanz, E; Chhowalla, M; Giulani, F

    2015-01-14

    Boron carbide is one of the lightest and hardest ceramics, but its applications are limited by its poor stability against a partial phase separation into separate boron and carbon. Phase separation is observed under high non-hydrostatic stress (both static and dynamic), resulting in amorphization. The phase separation is thought to occur in just one of the many naturally occurring polytypes in the material, and this raises the possibility of doping the boron carbide to eliminate this polytype. In this work, we have synthesized boron carbide doped with silicon. We have conducted a series of characterizations (transmission electron microscopy, scanning electron microscopy, Raman spectroscopy and x-ray diffraction) on pure and silicon-doped boron carbide following static compression to 50 GPa non-hydrostatic pressure. We find that the level of amorphization under static non-hydrostatic pressure is drastically reduced by the silicon doping. PMID:25427850

  20. Stabilization of boron carbide via silicon doping

    Science.gov (United States)

    Proctor, J. E.; Bhakhri, V.; Hao, R.; Prior, T. J.; Scheler, T.; Gregoryanz, E.; Chhowalla, M.; Giulani, F.

    2015-01-01

    Boron carbide is one of the lightest and hardest ceramics, but its applications are limited by its poor stability against a partial phase separation into separate boron and carbon. Phase separation is observed under high non-hydrostatic stress (both static and dynamic), resulting in amorphization. The phase separation is thought to occur in just one of the many naturally occurring polytypes in the material, and this raises the possibility of doping the boron carbide to eliminate this polytype. In this work, we have synthesized boron carbide doped with silicon. We have conducted a series of characterizations (transmission electron microscopy, scanning electron microscopy, Raman spectroscopy and x-ray diffraction) on pure and silicon-doped boron carbide following static compression to 50 GPa non-hydrostatic pressure. We find that the level of amorphization under static non-hydrostatic pressure is drastically reduced by the silicon doping.

  1. Burnup performances of boron nitride and boron coated nuclear fuels

    International Nuclear Information System (INIS)

    The nuclear fuels of urania (UOV) and 5% and 10% gadolinia (Gd2O3) containing UO2 previously produced by sol-gel technique were coated with first boron nitride (BN) then boron (B) thin layer by chemical vapor deposition (CVD) and also by plasma enhanced chemical vapor deposition (PECVD) techniques to increase the fuel cycle length and to improve the physical properties. From the cross-sectional view of BN and B layers taken from scanning electron microscope (SEM), the excellent adherence of BN onto fuel and B onto BN layer was observed in both cases. The behavior of fuel burnup, depletion of BN and B, the effect of coating thickness and also Gd2O3 content on the burnup performances of the fuels were identified by using the code WIMS-D/4 for Pressurized Water Reactor (PWR) and Boiling Water Reactor (BWR) cores. The optimum thickness ratio of B to BN was found as 4 and their thicknesses were chosen as 40 mm and 10 mm respectively in both reactor types to get extended cycle length. The assemblies consisting of fuels with 5% Gd2O3 and also coated with 10 mm BN and 40 mm B layers were determined as candidates for getting higher burnup in both types of reactors

  2. Boron enrichment in martian clay.

    Directory of Open Access Journals (Sweden)

    James D Stephenson

    Full Text Available We have detected a concentration of boron in martian clay far in excess of that in any previously reported extra-terrestrial object. This enrichment indicates that the chemistry necessary for the formation of ribose, a key component of RNA, could have existed on Mars since the formation of early clay deposits, contemporary to the emergence of life on Earth. Given the greater similarity of Earth and Mars early in their geological history, and the extensive disruption of Earth's earliest mineralogy by plate tectonics, we suggest that the conditions for prebiotic ribose synthesis may be better understood by further Mars exploration.

  3. Boron enrichment in martian clay.

    Science.gov (United States)

    Stephenson, James D; Hallis, Lydia J; Nagashima, Kazuhide; Freeland, Stephen J

    2013-01-01

    We have detected a concentration of boron in martian clay far in excess of that in any previously reported extra-terrestrial object. This enrichment indicates that the chemistry necessary for the formation of ribose, a key component of RNA, could have existed on Mars since the formation of early clay deposits, contemporary to the emergence of life on Earth. Given the greater similarity of Earth and Mars early in their geological history, and the extensive disruption of Earth's earliest mineralogy by plate tectonics, we suggest that the conditions for prebiotic ribose synthesis may be better understood by further Mars exploration. PMID:23762242

  4. Validation of an automated fluorescein method for determining bromide in water

    Science.gov (United States)

    Fishman, M. J.; Schroder, L.J.; Friedman, L.C.

    1985-01-01

    Surface, atmospheric precipitation and deionized water samples were spiked with ??g l-1 concentrations of bromide, and the solutions stored in polyethylene and polytetrafluoroethylene bottles. Bromide was determined periodically for 30 days. Automated fluorescein and ion chromatography methods were used to determine bromide in these prepared samples. Analysis of the data by the paired t-test indicates that the two methods are not significantly different at a probability of 95% for samples containing from 0.015 to 0.5 mg l-1 of bromide. The correlation coefficient for the same sets of paired data is 0.9987. Recovery data, except for the surface water samples to which 0.005 mg l-1 of bromide was added, range from 89 to 112%. There appears to be no loss of bromide from solution in either type of container.Surface, atmospheric precipitation and deionized water samples were spiked with mu g l** minus **1 concentrations of bromide, and the solutions stored in polyethylene and polytetrafluoroethylene bottles. Bromide was determined periodically for 30 days. Automated fluorescein and ion chromatography methods were used to determine bromide in these prepared samples. Analysis of the data by the paired t-test indicates that the two methods are not significantly different at a probability of 95% for samples containing from 0. 015 to 0. 5 mg l** minus **1 of bromide. The correlation coefficient for the same sets of paired data is 0. 9987. Recovery data, except for the surface water samples to which 0. 005 mg l** minus **1 of bromide was added, range from 89 to 112%. Refs.

  5. Experimental boron neutron capture therapy for melanoma: Systemic delivery of boron to melanotic and amelanotic melanoma

    International Nuclear Information System (INIS)

    The boron-containing melanin precursor analogue p-boronophenylalanine (BPA) has previously been shown to selectively deliver boron to pigmented murine melanomas when administered in a single intragastric dose. If boron neutron capture therapy is to become a clinically useful method of radiation therapy for human malignant melanoma, the boron carrier must be capable of delivering useful amounts of boron to remote tumor sites (metastases) and to poorly pigmented melanomas. The authors have now determined the ability of BPA to accumulate in several nonpigmented melanoma models including human melanoma xenografts in nude mice. The absolute amount of boron in the nonpigmented melanomas was about 50% of the observed in the pigmented counterparts but was still selectively concentrated in the tumor relative to normal tissues in amounts sufficient for effective neutron capture therapy. Single intragastric doses of BPA resulted in selective localization of boron in the amelanotic Greene melanoma carried in the anterior chamber of the rabbit eye and in a pigmented murine melanoma growing in the lungs. The ratio of the boron concentration in these tumors to the boron concentration in the immediately adjacent normal tissue was in the range of 3:1 to 4:1. These distribution studies support the proposal that boron neutron capture therapy may be useful as a regional therapy for malignant melanoma

  6. Determination of micro-amount bromide in uranium trioxide by spectrophotometric method

    International Nuclear Information System (INIS)

    The content of bromide in the production of uranium trioxide is one of the most important control factors, so determining it accurately seems important. When uranium trioxide is dissolved in nitric acid, in the presence of AgNO3 solution, micro-amount bromide can be co- precipitated with AgCl. Bromide can be separated by centrifugation from a large amount of UO22+ and other anions. In the existing of KOH and H2O2, AgCl can be changed into free bromide. By adding ammonium molybdate as catalyst, bromide and excessive KBrO3 can react and produce Br2. In the medium of tert-butanol-ethanol, Br2 can react with basic fuchsine and produce a purple compound which is stable, the bromide content is determined by spectrophotometric method. The results show that it is a highly sensitive method with low detection limit. Its apparent molar absorption coefficient κ' is 1.7 x 104 L/(mol·cm). Its detection limit is 9 μg/L and determination limit is 0.13 mg/L. The linear relationship is in the range of 0.2-1.6 mg/L with a correlation coefficient of 0.997. The relative standard deviation is less than 10% after it is determed six times at the same time. For bromide content of 4.00 and 8.00 μg, the bromide recovery obtained are between 94% and 103%. (authors)

  7. Removal of bromide by aluminium chloride coagulant in the presence of humic acid.

    Science.gov (United States)

    Ge, Fei; Shu, Haimin; Dai, Youzhi

    2007-08-17

    Bromide can form disinfection by-products (DBPs) in drinking water disinfection process, which have adverse effects on human health. Using aluminium chloride as a model coagulant, removal of bromide by coagulation was investigated in the absence or presence of humic acid (HA) in synthetic water and then was conducted in raw water. Results demonstrated that in synthetic water, 93.3-99.2% removal efficiency of bromide was achieved in the absence of HA with 3-15 mg/L coagulant, while 78.4-98.4% removal efficiency of bromide was obtained in the presence of HA with the same coagulant dosage and 86.8-98.8% HA was removed simultaneously. Bromide in raw water was removed 87.0% with 15 mg/L coagulant. HA apparently reduced the removal of bromide with low coagulant dosage or at high pH, while minor influence on removal of bromide was observed with high coagulant dosage or at low pH. Thus, bromide could be reduced effectively by enhanced coagulation in drinking water treatment. PMID:17289257

  8. SYNTHESIS AND CATALYTIC PROPERTIES OF HYDROPHOBICALLY MODIFIED POLY(ALKYLMETHYLDIALLYLAMMONIUM BROMIDES)

    NARCIS (Netherlands)

    YANG, YJ; ENGBERTS, JBFN

    1991-01-01

    A series of hydrophobically modified homo- and copolymers of the poly(alkylmethyldiallylammonium bromide) type has been prepared by free-radical cyclo(co)polymerization of alkylmethyldiallylammonium bromide monomers in aqueous solution. Depending on the length of the alkyl side chain (varied between

  9. Acrolein as Potential Alternative to Methyl Bromide in California-Grown Calla Lilies

    Science.gov (United States)

    Cut flower and ornamental bulb industries rely heavily on a methyl bromide/chloropicrin (MB/Pic) mixture as a key pest management tool. The loss of methyl bromide (MB) will seriously affect the cut flower and bulb industry, and in the future, will require growers to use alternative fumigants. Theref...

  10. The method of molecular dynamics in ethidium bromide-DNA interaction research

    International Nuclear Information System (INIS)

    The interaction of ethidium bromide with the DNA by the method of molecular dynamics was studied. The geometric and energy parameters of DNA-ethidium bromide connectivity had been calculated. A comparative analysis of the experimentally identified connectivity parameters by different methods and parameters of molecular dynamics method had been carried out

  11. Colorimetric Sugar Sensing Using Boronic Acid-Substituted Azobenzenes

    OpenAIRE

    Yuya Egawa; Ryotaro Miki; Toshinobu Seki

    2014-01-01

    In association with increasing diabetes prevalence, it is desirable to develop new glucose sensing systems with low cost, ease of use, high stability and good portability. Boronic acid is one of the potential candidates for a future alternative to enzyme-based glucose sensors. Boronic acid derivatives have been widely used for the sugar recognition motif, because boronic acids bind adjacent diols to form cyclic boronate esters. In order to develop colorimetric sugar sensors, boronic acid-conj...

  12. Synthesis and characterization of ammonium phosphate fertilizers with boron

    OpenAIRE

    ANGELA MAGDA; RODICA PODE; CORNELIA MUNTEAN; MIHAI MEDELEANU; ALEXANDRU POPA

    2010-01-01

    The concentration of boron, an essential micronutrient for plants, presents a narrow range between deficiency and toxicity. In order to provide the boron requirement for plants, and to avoid toxicity problems, boron compounds are mixed with basic fertilizers. Sodium borate pentahydrate was used as a boron source. Ammonium orthophosphates fertilizers with boron were prepared by neutralizing phosphoric acid with ammonia and addition of variable amounts of sodium tetraborate pentahydrate to the ...

  13. Xanthine Biosensor Based on Didodecyldimethylammonium Bromide Modified Pyrolytic Graphite Electrode

    Institute of Scientific and Technical Information of China (English)

    TANG,Ji-Lin(唐纪琳); HAN,Xiao-Jun(韩晓军); HUANG,Wei-Min(黄卫民); WANG,Er-Kang(汪尔康)

    2002-01-01

    The vesicle of didodecyldimethylammonium bromide (DDAB)which contained tetrathiafulvalene (TTF) was mixed with xanthine oxidase, and the mixture was cast on the pyrolytic graphite electrode. The lipid films were used to supply a biological environment resembling biomembrane on the surface of the electrode. TTF was used as a mediator because of its high electron-transfer efficiency. A novel xanthine biosensor based on cast DDAB film was developed. The effects of pH and operating potential were explored for optimum analytical performance by using the amperometric method. The response time of the biosensor was less than 10 s. The detection limit of the biosensor was 3.2 × 10-7 mol/L and the liner range was from 4 × 10-7 mol/L to 2.4 × 10-6 mol/L.

  14. Solvent effects in the reaction between piperazine and benzyl bromide

    Indian Academy of Sciences (India)

    S Ranga Reddy; P Manikyamba

    2007-11-01

    The reaction between piperazine and benzyl bromide was studied conductometrically and the second order rate constants were computed. These rate constants determined in 12 different protic and aprotic solvents indicate that the rate of the reaction is influenced by electrophilicity (), hydrogen bond donor ability () and dipolarity/polarizability (*) of the solvent. The LSER derived from the statistical analysis indicates that the transition state is more solvated than the reactants due to hydrogen bond donation and polarizability of the solvent while the reactant is more solvated than the transition state due to electrophilicity of the solvent. Study of the reaction in methanol, dimethyl formamide mixtures suggests that the rate is maximum when dipolar interactions between the two solvents are maximum.

  15. Timing resolution measurements of a 3 in. lanthanum bromide detector

    Energy Technology Data Exchange (ETDEWEB)

    Galli, L., E-mail: luca.galli@pi.infn.it [INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); De Gerone, M. [INFN Sezione di Genova, Largo Dodecaneso 33, 16146 Genova (Italy); Dipartimento di Fisica dell' Università degli Studi di Genova, Largo Dodecaneso 33, 16146 Genova (Italy); Dussoni, S. [INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Nicolò, D. [INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Dipartimento di Fisica dell' Università degli Studi di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Papa, A. [Paul Scherrer Institute PSI, CH-5232 Villigen (Switzerland); Tenchini, F. [INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Dipartimento di Fisica dell' Università degli Studi di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Signorelli, G. [INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy)

    2013-08-01

    Cerium-doped lanthanum bromide (LaBr{sub 3}:Ce) is a scintillator that presents very good energy and timing resolutions and it is a perfect candidate for photon detector in future experiments to search for lepton flavor violation as in μ→eγ or μ→e conversion. While energy resolution was thoroughly investigated, timing resolution at several MeV presents some experimental challenge. We measured the timing resolution of a 3 in.×3 in. cylindrical LaBr{sub 3}(Ce) crystal versus few reference detectors by means of a nuclear reaction from a Cockcroft–Walton accelerator that produces coincident γ-rays in the 4.4–11.6 MeV range. Preliminary results allow us to extrapolate the properties of a segmented γ-ray detector in the 50–100 MeV range.

  16. Optical studies of X-irradiated sodium bromide single crystals

    International Nuclear Information System (INIS)

    Optical absorption of sodium bromide single crystals colored by X-rays for durations ranging from 8 hours to 200 hours at room temperature has been studied. Two well-resolved absorption bands one at 535 nm (F-band) and the other at 255 nm have been observed in all the samples. Another band at 840 nm (M-band) has also been observed when the irradiation time was extended to 200 hours. A band at 770 nm has been detected for the first time during the process of optical bleaching. The effects of optical bleaching with F-band light on these absorption bands have been studied in detail for durations ranging from a few seconds to 1820 minutes at temperature below the coloration temperature. (author)

  17. Irradiation as an alternative to methyl bromide: the Australian situation

    International Nuclear Information System (INIS)

    International agreement to phase out the fumigant Methyl bromide (MeBr) will have serious implications for pest and disease control in Australia, particularly grain pest control, quarantine usage on fresh horticultural produce and control of soil pathogens or nematodes. Irradiation is a practical alternative but is not currently approved for use in Australia. Other options are available but none of the viable methods except irradiation have the short application time needed for treatment of grams found to be infested during loading at export. This usage is vital, as Australian grain is exported at very high standards of freedom from insects, assured by Government regulatory requirements. Irradiation is contrasted against other alternatives including heat and cold, especially for fresh horticultural produce. (author)

  18. Mechanism of the Deaquation of Aquopentaaminocobalt(Ⅲ) Bromide

    Institute of Scientific and Technical Information of China (English)

    MA,Li-Dun(马礼敦); CHENG,Guang-Hui(程广辉); WU,Hong-Xiang(吴宏翔); LIN,Han-Yi(林涵毅); SHEN,Xiao-Liang(沈孝良); SHI,Guo-Shun(施国顺)

    2002-01-01

    There are two theories, SN1 and SN2, for the mechanism of the deaquation of aquopentaamincobalt(Ⅲ) bromide (AAC-B).Both of the theories are supported by some experimental and calculated data. But there are not any experiments to determine directly the structure of the intermediates at different reaction time. In this paper the structures of the intermediates at different reaction time in deaquation-anation of AACB were de-termined by extended X-ray absorption fine structure (EXAFS)and the reaction process wes studied by the combination of Xray powder diffraction and EXAFS. It was demonstrated that the deaquation-anation of AACB obeys the SN2 theory.

  19. Radioiodine tracers as useful tools in studies of thyrotoxic effects of exogenous bromide and perchlorate ions

    International Nuclear Information System (INIS)

    With the use of 125I and 131I radionuclides, we followed the effects of exogenous bromide and perchlorate ions on the metabolism of iodine and of thyroid hormone in the rat. The presumed thyrotoxic effects of bromide and perchlorate have been confirmed and quantified. Correct assay conditions for the radiometric determination of the enzyme activity of thyroid peroxidase (TPO) have been established. The use of the adapted radiometric assay revealed a divergent influence of bromide and perchlorate ions on the TPO activity in the rat thyroids. Excessive bromide exerted a biphasic effect, depending on the extent of bromide intake in the animals. In contrast, in all the rats that were administered with high amounts of perchlorate were found elevated TPO activities. (author)

  20. The determination of boron and carbon in reactor grade boron carbide

    International Nuclear Information System (INIS)

    The sealed tube method of dissolution at high temperature and pressure has been successfully applied in the analysis of reactor grade boron carbide for the determination of boron. A 50 mg sample of boron carbide is completely dissolved by heating with concentrated nitric acid in a sealed tube at 3000C. The boron content of the resultant sample solution is determined by the mannitol potentiometric titration method. The precision of the method for the determination of 2.5 mg of boron using the Harwell automatic potentiometric titrator is 0.2% (coefficient of variation). The carbon content of a boron carbide sample is determined by combustion of the sample at 10500C in a stream of oxygen using vanadium pentoxide to ensure the complete oxidation of the sample. The carbon dioxide produced from the sample is measured manometrically and the precision of the method for the determination of 4 mg of carbon is 0.4% (coefficient of variation). (author)

  1. Proceedings of workshop on 'Boron Chemistry and Boron Neutron Capture Therapy'

    International Nuclear Information System (INIS)

    This volume contains the proceedings of the 3rd Workshop on 'the Boron Chemistry and Boron Neutron Capture Therapy' held on February 12, in 1991. In this workshop, our attention was focused on the chemical nature of boron compounds and the boron neutron capture therapy (BNCT). First, clinical experiences of BNCT in KURRI in 1990 and 1991 were reported (Chap. 3). The feasibility of the gadolinium neutron capture therapy for brain tumors was discussed (Chap. 4). In the chemical field, a rapid spectrophotometric determination of trace amounts of borons in biological samples is described (Chap. 5). The chemical behaviours of p-boronophenylalanine and its analogs in aqueous solutions were investigated by a paper electrophoresis and infrared spectroscopy (Chap. 6). On the molecular design and synthesis of new boron carriers for BNCT, several new synthetic methods for B-10 containing nucleoside derivatives were shown (Chap. 7). (author)

  2. Quantitative boron detection by neutron transmission method

    International Nuclear Information System (INIS)

    //Quantitative boron detection is mainly performed by chemical methods like colorimetric titration. High neutron absorption cross section of natural boron makes attractive its detection by absorption measurements. This work is an extension of earlier investigations where neutron radiography technique was used for boron detection. In the present investigation, the neutron absorption rate of boron containing solutions is the way to measure quantitatively the boron content of the solutions. The investigation was carried out in Istanbul TRIGA Mark-II reactor. In the end of the experiments, it was observed that even |ppw| grade boron in aqueous solution can be easily detected. The use of this method is certainly very useful for boron utilizing industries like glass and steel industries.The major disadvantage of the method is the obligation to use always aqueous solutions to be able to detect homogeneously the boron content. Then, steel or glass samples have to be put first in an appropriate solution form. The irradiation of steel samples can give the distribution of boron by the help of a imaging and this suggested method will give its quantitative measurement. The superiority of this method are its quick response time and its accuracy. To test this accuracy, a supposed unknown , solution of boric acid is irradiated and then calculated by the help of the calibration curve. The measured value of boric acid was 0.89 mg and the calculated value was found to be 0.98 mg which gives an accuracy of 10 %. It was also seen that the method is more accurate for low concentration. (authors)

  3. X-ray diffraction study of boron produced by pyrolysis of boron tribromide

    Science.gov (United States)

    Rosenberg, David

    The goal of this research was to determine the composition of boron deposits produced by pyrolysis of boron tribromide, and to use the results to (a) determine the experimental conditions (reaction temperature, etc.) necessary to produce alpha-rhombohedral boron and (b) guide the development/refinement of the pyrolysis experiments such that large, high purity crystals of alpha-rhombohedral boron can be produced with consistency. Developing a method for producing large, high purity alpha-rhombohedral boron crystals is of interest because such crystals could potentially be used to achieve an alpha-rhombohedral boron based neutron detector design (a solid-state detector) that could serve as an alternative to existing neutron detector technologies. The supply of neutron detectors in the United States has been hampered for a number of years due to the current shortage of helium-3 (a gas used in many existing neutron detector technologies); the development of alternative neutron detector technology such as an alpha-rhombohedral boron based detector would help provide a more sustainable supply of neutron detectors in this country. In addition, the prospect/concept of an alpha-rhombohedral boron based neutron detector is attractive because it offers the possibility of achieving a design that is smaller, longer life, less power consuming, and potentially more sensitive than existing neutron detectors. The main difficulty associated with creating an alpha-rhombohedral boron based neutron detector is that producing large, high purity crystals of alpha-rhombohedral boron is extremely challenging. Past researchers have successfully made alpha-rhombohedral boron via a number of methods, but no one has developed a method for consistently producing large, high purity crystals. Alpha-rhombohedral boron is difficult to make because it is only stable at temperatures below around 1100-1200 °C, its formation is very sensitive to impurities, and the conditions necessary for its

  4. Sintering of boron carbide (B4C)

    International Nuclear Information System (INIS)

    Boron carbide (B4C) is used as a control element in different types of reactors due to the high fast and thermal neutron absorption cross-section of B-10. Requirements of the Advanced Reactor Division of the Bariloche Atomic Center triggered the study of the possibilities of fabricating B4C pellets by cold-pressing and sintering. The results of essays of sinterability of two different commercial boron carbide powders, sintered at temperatures between 1200 and 2200 deg C, are given. Characterizations of the samples were made to determine the evolution of density, porosity, microstructure and boron content as a function of sintering temperature. (Author)

  5. Developments in boron magnetic resonance imaging (MRI)

    Energy Technology Data Exchange (ETDEWEB)

    Schweizer, M.

    1995-11-01

    This report summarizes progress during the past year on maturing Boron-11 magnetic resonance imaging (MRI) methodology for noninvasive determination of BNCT agents (BSH) spatially in time. Three major areas are excerpted: (1) Boron-11 MRI of BSH distributions in a canine intracranial tumor model and the first human glioblastoma patient, (2) whole body Boron-11 MRI of BSH pharmacokinetics in a rat flank tumor model, and (3) penetration of gadolinium salts through the BBB as a function of tumor growth in the canine brain.

  6. First boronization in KSTAR: Experiences on carborane

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Suk-Ho, E-mail: sukhhong@nfri.re.kr [National Fusion Research Institute, 113 Gwahangno, Yusung-Gu, Daejeon 305-333 (Korea, Republic of); Center for Edge Plasma Science (cEps), Hanyang University, Seoul 133-791 (Korea, Republic of); Lee, Kun-Su; Kim, Kwang-Pyo; Kim, Kyung-Min; Kim, Hong-Tack [National Fusion Research Institute, 113 Gwahangno, Yusung-Gu, Daejeon 305-333 (Korea, Republic of); Sun, Jong-Ho; Woo, Hyun-Jong [Center for Edge Plasma Science (cEps), Hanyang University, Seoul 133-791 (Korea, Republic of); Department of Electrical Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Park, Jae-Min [National Fusion Research Institute, 113 Gwahangno, Yusung-Gu, Daejeon 305-333 (Korea, Republic of); Park, Eun-Kyong [Center for Edge Plasma Science (cEps), Hanyang University, Seoul 133-791 (Korea, Republic of); Department of Electrical Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Kim, Woong-Chae; Kim, Hak-Kun; Park, Kap-Rai; Yang, Hyung-Lyeol; Oh, Yeong-Kook; Na, Hoon-Kyun [National Fusion Research Institute, 113 Gwahangno, Yusung-Gu, Daejeon 305-333 (Korea, Republic of); Lho, Taehyeop [National Fusion Research Institute, 113 Gwahangno, Yusung-Gu, Daejeon 305-333 (Korea, Republic of); Center for Edge Plasma Science (cEps), Hanyang University, Seoul 133-791 (Korea, Republic of); Chung, Kyu-Sun [Center for Edge Plasma Science (cEps), Hanyang University, Seoul 133-791 (Korea, Republic of); Department of Electrical Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2011-08-01

    First boronization was performed in KSTAR tokamak during 2009 campaign in order to reduce oxygen impurities and to lower the power loss due to radiation. We report the results from the experiences on carborane during the first boronization in KSTAR. After the boronization, H{sub 2}O and O{sub 2} level in the vacuum vessel are reduced significantly. The characteristics of the deposited thin films were analyzed by variable angle spectroscopic ellipsometry, XPS, and AES. {approx}1.78 x 10{sup 16} cm{sup -2} s{sup -1} of carbon flux on the wall is estimated by using cavity technique.

  7. Boron site preference in ternary Ta and Nb boron silicides

    International Nuclear Information System (INIS)

    X-ray single crystal (XSC) and neutron powder diffraction data (NPD) were used to elucidate boron site preference for five ternary phases. Ta3Si1−xBx (x=0.112(4)) crystallizes with the Ti3P-type (space group P42/n) with B-atoms sharing the 8g site with Si atoms. Ta5Si3−x (x=0.03(1); Cr5B3- type) crystallizes with space group I4/mcm, exhibiting a small amount of vacancies on the 4a site. Both, Ta5(Si1−xBx)3, x=0.568(3), and Nb5(Si1−xBx)3, x=0.59(2), are part of solid solutions of M5Si3 with Cr5B3-type into the ternary M–Si–B systems (M=Nb or Ta) with B replacing Si on the 8h site. The D88-phase in the Nb–Si–B system crystallizes with the Ti5Ga4-type revealing the formula Nb5Si3B1−x (x=0.292(3)) with B partially filling the voids in the 2b site of the Mn5Si3 parent type. - Graphical abstract: The crystal structures of a series of compounds have been solved from X-ray single crystal diffractometry revealing details on the boron incorporation. Highlights: ► Structure of a series of compounds have been solved by X-ray single crystal diffractometry. ► Ta3(Si1−xBx) (x=0.112) crystallizes with the Ti3P-type, B and Si atoms randomly share the 8g site. ► Structure of Nb5Si3B1−x (x=0.292; Ti5Ga4-type) was solved from NPD.

  8. Synthesis of Boron Nanorods by Smelting Non-Toxic Boron Oxide in Liquid Lithium

    OpenAIRE

    Amartya Chakrabarti; Tao Xu; Laura K. Paulson; Krise, Kate J.; Maguire, John A; Hosmane, Narayan S.

    2010-01-01

    In contrast to the conventional bottom-up syntheses of boron nanostructures, a unique top-down and greener synthetic strategy is presented for boron nanorods involving nontoxic boron oxide powders ultrasonically smelted in liquid lithium under milder conditions. The product was thoroughly characterized by energy dispersive X-ray analysis, atomic emission spectroscopy, thermogravimetric analysis and, UV-Vis spectroscopy, including structural characterization by transmission electron microscop...

  9. Determination of boron isotope ratios in boron carbide by mass spectrometry

    International Nuclear Information System (INIS)

    This paper introduces the direct determination of boron isotope ratios in the boron carbide powder by thermal ionization mass spectrometry. The technique for sample loading, the procedure for heating and the eliminating of effects induced by oxygen are studied. The study indicates that the preparing process for the sample will be shorted, and the time for determination and the exposure dose of the laboratory assistant will be reduced for the reason of directly determination of boron carbide. (authors)

  10. Effect of boron concentration on physicochemical properties of boron-doped carbon nanotubes

    International Nuclear Information System (INIS)

    Boron-doped carbon nanotubes (B-CNTs) were synthesized using chemical vapour deposition (CVD) floating catalyst method. Toluene was used as the carbon source, triphenylborane as boron as well as the carbon source while ferrocene was used as the catalyst. The amount of triphenylborane used was varied in a solution of toluene and ferrocene. Ferrocene was kept constant at 2.5 wt.%. while a maximum temperature of 900 °C was used for the synthesis of the shaped carbon nanomaterial (SCNMs). SCNMs obtained were characterized by the use of transmission electron microscope (TEM), scanning electron microscope (SEM), high resolution-electron microscope, electron dispersive X-ay spectroscopy (EDX), Raman spectroscopy, inductively coupled plasma-optical emission spectroscopy (ICP-OES), vibrating sample magnetometer (VSM), nitrogen adsorption at 77 K, and inverse gas chromatography. TEM and SEM analysis confirmed SCNMs obtained were a mixture of B-CNTs and carbon nanofibres (B-CNF). EDX and ICP-OES results showed that boron was successively incorporated into the carbon hexagonal network of CNTs and its concentration was dependent on the amount of triphenylborane used. From the VSM results, the boron doping within the CNTs introduced ferromagnetic properties, and as the percentage of boron increased the magnetic coactivity and squareness changed. In addition, boron doping changed the conductivity and the surface energy among other physicochemical properties of B-CNTs. - Highlights: • Boron-doping of carbon nanotubes (CNTs) changes their physiochemical properties. • Amount of boron-doping was dependent on the wt.% of boron precursor used. • Boron-doping changed CNTs surfaces and the distribution of dispersive energy sites. • Boron-doping affected the conductivity and ferromagnetic properties. • Increased boron-doping results in a more favourable interaction with polar probes

  11. Investigation of boron extraction process with aid magnesium hydroxide from mother liquor of boron production

    International Nuclear Information System (INIS)

    Conditions of boron - magnesium concentrate preparation from mother liquor by coprecipitation of borate - ions by magnesium hydroxide are investigated. It is shown that boron - magnesium concentrate and products of its heat treatment at 100 - 500 deg C in water are dissolved partially, and in ammonium citrate - practically completely. Suppositions are made on the composition of the product prepared, on the the structure of its crystal lattice and the processes taking place in it during heat treatment. The conclusion is made on the perspectiveness of processing of mother liquor of boron industry for boron - magnesium concentrate

  12. Boron

    International Nuclear Information System (INIS)

    This paper reports that borate minerals and refined borates are used extensively for the manufacture of vitreous materials such as insulation and textile fiberglasses, borosilicate glass, and porcelain enamels and frits. In North America, these applications are estimated to account for over 54% of the borate consumption. Other substantial uses are in soaps and detergents, metallurgy, fire retardants, industrial biocides, agriculture, and various miscellaneous applications. Reported domestic borate consumption in 1990 was estimated by the U.S. Bureau of Mines to be 320 000 metric tons B2O3 versus 354 000 metric tons B2O3 in 1989. Consumption is projected to remain essentially static in 1991. Imports were estimated by the Bureau to be 50 000 metric tons B2O3 in 1990. Exports of boric acid and refined borates were approximately 650 000 metric tons of product, a 15 000 metric ton increase from the 1989 level. This increase partially offsets the drop in the 1990 consumption level

  13. Boron-isotope fractionation in plants

    International Nuclear Information System (INIS)

    Naturally-occurring variations in the abundance of stable isotopes of carbon, nitrogen, oxygen, and other elements in plants have been reported and are now used to understand various physiological processes in plants. Boron (B) isotopic variation in several plant species have been documented, but no determination as to whether plants fractionate the stable isotopes of boron, 11B and 10B, has been made. Here, we report that plants with differing B requirements (wheat, corn and broccoli) fractionated boron. The whole plant was enriched in 11B relative to the nutrient solution, and the leaves were enriched in 10B and the stem in 11B relative to the xylem sap. Although at present, a mechanistic role for boron in plants is uncertain, potential fractionating mechanisms are discussed. (author)

  14. Synthesis of Boron-Containing Primary Amines

    Directory of Open Access Journals (Sweden)

    Sheng-Hsuan Chung

    2013-10-01

    Full Text Available In this study, boron-containing primary amines were synthesized for use as building blocks in the study of peptoids. In the first step, Gabriel synthesis conditions were modified to enable the construction of seven different aminomethylphenyl boronate esters in good to excellent yields. These compounds were further utilized to build peptoid analogs via an Ugi four-component reaction (Ugi-4CR under microwave irradiation. The prepared Ugi-4CR boronate esters were then successfully converted to the corresponding boronic acids. Finally, the peptoid structures were successfully modified by cross-coupling to aryl/heteroaryl chlorides via a palladium-mediated Suzuki coupling reaction to yield the corresponding derivatives in moderate to good yields.

  15. Boron toxicity in oil palm (Elaeis guineensis)

    Energy Technology Data Exchange (ETDEWEB)

    Rajaratnam, J.A.

    1973-01-01

    Potted oil palms were treated with fertilizer of borate-46 at several concentrations and the plants were observed for boron toxicity effects. Toxicity symptoms were apparent at high rates but not at rates equivalent to typical Malaysian soils.

  16. Boron adsorption on hematite and clinoptilolite

    International Nuclear Information System (INIS)

    This thesis describes experiments performed to determine the suitability of boron as a potential reactive tracer for use in saturated-zone C-well reactive tracer studies for the Yucca Mountain Project (YMP). Experiments were performed to identify the prevalent sorption mechanism of boron and to determine adsorption of boron on hematite and clinoptilolite as a function of pH. These minerals are present in the Yucca Mountain tuff in which the C-well studies will be conducted. Evaluation of this sorption mechanism was done by determining the equilibration time of boron-mineral suspensions, by measuring changes in equilibrium to titrations, and by measuring electrophoretic mobility. Experiments were performed with the minerals suspended in NaCl electrolytes of concentrations ranging from 0.1 N NaCl to 0.001 N NaCl. Experimentalconditions included pH values between 3 and 12 and temperature of about 38 degrees C

  17. Boron-Filled Hybrid Carbon Nanotubes.

    Science.gov (United States)

    Patel, Rajen B; Chou, Tsengming; Kanwal, Alokik; Apigo, David J; Lefebvre, Joseph; Owens, Frank; Iqbal, Zafar

    2016-01-01

    A unique nanoheterostructure, a boron-filled hybrid carbon nanotube (BHCNT), has been synthesized using a one-step chemical vapor deposition process. The BHCNTs can be considered to be a novel form of boron carbide consisting of boron doped, distorted multiwalled carbon nanotubes (MWCNTs) encapsulating boron nanowires. These MWCNTs were found to be insulating in spite of their graphitic layered outer structures. While conventional MWCNTs have great axial strength, they have weak radial compressive strength, and do not bond well to one another or to other materials. In contrast, BHCNTs are shown to be up to 31% stiffer and 233% stronger than conventional MWCNTs in radial compression and have excellent mechanical properties at elevated temperatures. The corrugated surface of BHCNTs enables them to bond easily to themselves and other materials, in contrast to carbon nanotubes (CNTs). BHCNTs can, therefore, be used to make nanocomposites, nanopaper sheets, and bundles that are stronger than those made with CNTs. PMID:27460526

  18. Boron neutron capture therapy. What is next?

    International Nuclear Information System (INIS)

    BNCT (Boron Neutron Capture Therapy) will have difficulties establishing itself without efficient and conclusive clinical trials of glioma, without the expansion to other tumors, and without efficient programs for compound development and testing. (author)

  19. Ni doping of semiconducting boron carbide

    International Nuclear Information System (INIS)

    The wide band gap, temperature stability, high resistivity, and robustness of semiconducting boron carbide make it an attractive material for device applications. Undoped boron carbide is p type; Ni acts as a n-type dopant. Here we present the results of controlled doping of boron carbide with Ni on thin film samples grown using plasma enhanced chemical vapor deposition. The change in the dopant concentration within the thin film as a function of the dopant flow rate in the precursor gas mixture was confirmed by x-ray photoelectron spectroscopy measurements; with increasing dopant concentration, current-voltage (I-V) curves clearly establish the trend from p-type to n-type boron carbide.

  20. Analysis of boron at Koeberg Power Station

    International Nuclear Information System (INIS)

    Soluble reactivity poisons, also called chemical shim, produce spatially uniform neutron absorption when dissolved in reactor coolant water. The boron-10 isotope having a high neutron absorption coefficient is used in commercial pressurised water reactors (PWR) to limit and control reactivity. This is achieved at Koeberg Nuclear Power Station (KNPS) and the majority of commercial PWR's worldwide by the addition of natural boric acid to the reactor coolant. The boric acid dissolved in the coolant decreases the thermal utilisation factor, causing a decrease in reactivity. By varying the concentration of boric acid (and hence also the B-10 concentration) in the coolant, a process referred to as boration and dilution, the reactivity of the core can be easily managed. An increase in boron concentration (boration) creates negative reactivity and if the boron concentration is reduced (dilution), positive reactivity is added. The changing of boron concentration in a PWR is used primarily to compensate for fuel burn-up or poison build-up. The variation in boron concentration allows control rod use to be minimised, which results in a flatter flux profile over the core than can be produced by control rod manipulation. Accurate laboratory and on-line chemical analysis of boron concentration is important because of its operational implications associated with reactivity control and also for nuclear safety. In a normal fuel cycle, as the nuclear fuel is being consumed, the reactor coolant boric acid (B-10) concentration must be reduced by dilution with purified water to maintain the reactor at constant power. Besides in the reactor coolant water, boric acid concentration is also important in the chemical and volume control system and reactor make-up system for operation. For nuclear safety, boric acid concentrations are technical specification parameters, maintained and monitored in the spent fuel system and safety injection systems. Boron concentration determination is

  1. High temperature thermoelectric properties of boron carbide

    International Nuclear Information System (INIS)

    Boron carbides are refractory solids with potential for application as very high temperature p-type thermoelectrics in power conversion applications. The thermoelectric properties of boron carbides are unconventional. In particular, the electrical conductivity is consistent with the thermally activated hopping of a high density (∼1021/cm3) of bipolarons; the Seebeck coefficient is anomalously large and increases with increasing temperature; and the thermal conductivity is surprisingly low. In this paper, these unusual properties and their relationship to the unusual structure and bonding present in boron carbides are reviewed. Finally, the potential for utilization of boron carbides at very high temperatures (up to 2200 degrees C) and for preparing n-type materials is discussed

  2. Lithium-Beryllium-Boron : Origin and Evolution

    OpenAIRE

    Vangioni-Flam, Elisabeth; Casse, Michel; Audouze, Jean

    1999-01-01

    The origin and evolution of Lithium-Beryllium-Boron is a crossing point between different astrophysical fields : optical and gamma spectroscopy, non thermal nucleosynthesis, Big Bang and stellar nucleosynthesis and finally galactic evolution. We describe the production and the evolution of Lithium-Beryllium-Boron from Big Bang up to now through the interaction of the Standard Galactic Cosmic Rays with the interstellar medium, supernova neutrino spallation and a low energy component related to...

  3. Innovative boron nitride-doped propellants

    OpenAIRE

    Thelma Manning; Richard Field; Kenneth Klingaman; Michael Fair; John Bolognini; Robin Crownover; Carlton P. Adam; Viral Panchal; Eugene Rozumov; Henry Grau; Paul Matter; Michael Beachy; Christopher Holt; Samuel Sopok

    2016-01-01

    The U.S. military has a need for more powerful propellants with balanced/stoichiometric amounts of fuel and oxidants. However, balanced and more powerful propellants lead to accelerated gun barrel erosion and markedly shortened useful barrel life. Boron nitride (BN) is an interesting potential additive for propellants that could reduce gun wear effects in advanced propellants (US patent pending 2015-026P). Hexagonal boron nitride is a good lubricant that can provide wear resistance and lower ...

  4. A neutron diffraction study of amorphous boron

    Science.gov (United States)

    Delaplane, R. G.; Lundström, T.; Dahlborg, U.; Howells, W. S.

    1991-07-01

    The structure of amorphous boron has been studied with pulsed neutron diffraction techniques using the ISIS facilities at the Rutherford Appleton Laboratory. The experimental static structure factor S(Q) and radial distribution function support a structural model based on units of B12 icosahedra resembling those found in crystalline β-rhombohedral boron, but with a certain degree of disorder occurring in the linking between these subunits.

  5. The reactivity of phenancyl bromide under β-cyclodextrin as supramolecular catalyst: a computational survey.

    Science.gov (United States)

    Wan, Yali; Wang, Xueye; Liu, Na

    2015-05-01

    Phenacyl bromide as one starting material in multicomponent reactions (MCRs) with β-cyclodextrin (β-CD) as catalyst can get an excellent yield in short reaction times. The interaction of β-CD with phenacyl bromide plays an important role in this process. This paper studies the complex of β-CD with phenacyl bromide using density functional theory (DFT) method. Energy is investigated to find out the lowest energy of two possible complexation models. Hydrogen bonds are researched on the basis of natural bonding orbital (NBO) analysis. The relative position between phenacyl bromide and β-CD is confirmed by (1)H nuclear magnetic resonance ((1)HNMR). The results of frontier molecular orbitals and charge distribution reveal that β-CD catalyst improves the reactivity and electrophilicity of phenacyl bromide, meanwhile, the carbonyl group of phenacyl bromide more easily gives a carbocationic intermediate in the presence of β-CD as catalyst. The reactivity of phenancyl bromide under β-CD as supramolecular catalysis is improved. PMID:25929992

  6. Discharge cleaning on TFTR after boronization

    International Nuclear Information System (INIS)

    At the beginning of the 1990 TFTR experimental run, after replacement of POCO-AXF-5Q graphite tiles on the midplane of the bumper limiter by carbon fiber composite (CFC) tiles and prior to any Pulse Discharge Cleaning (PDC), boronization was performed. Boronization is the deposition of a layer of boron and carbon on the vacuum vessel inner surface by a glow discharge in a diborane, methane and helium mixture. The amount of discharge cleaning required after boronization was substantially reduced compared to that which was needed after previous openings when boronization was not done. Previously, after a major shutdown, about 105 low current (∼20 kA) Taylor Discharge Cleaning (TDC) pulses were required before high current (∼400 kA) aggressive Pulse Discharge Cleaning (PDC) pulses could be performed successfully. Aggressive PDC is used to heat the limiters from the vessel bakeout temperature of 150 degrees C to 250 degrees C for a period of several hours. Heating the limiters is important to increase the rate at which water is removed from the carbon limiter tiles. After boronization, the number of required TDC pulses was reduced to <5000. The number of aggressive PDC pulses required was approximately unchanged. 14 refs., 1 tab

  7. Amorphous boron nitride at high pressure

    Science.gov (United States)

    Durandurdu, Murat

    2016-06-01

    The pressure-induced phase transformation in hexagonal boron nitrite and amorphous boron nitrite is studied using ab initio molecular dynamics simulations. The hexagonal-to-wurtzite phase transformation is successfully reproduced in the simulation with a transformation mechanism similar to one suggested in experiment. Amorphous boron nitrite, on the other hand, gradually transforms to a high-density amorphous phase with the application of pressure. This phase transformation is irreversible because a densified amorphous state having both sp3 and sp2 bonds is recovered upon pressure release. The high-density amorphous state mainly consists of sp3 bonds and its local structure is quite similar to recently proposed intermediate boron nitrite phases, in particular tetragonal structure (P42/mnm), rather than the known the wurtzite or cubic boron nitrite due to the existence of four membered rings and edge sharing connectivity. On the basis of this finding we propose that amorphous boron nitrite might be best candidate as a starting structure to synthesize the intermediate phase(s) at high pressure and temperature (probably below 800 °C) conditions.

  8. Inheritance of Boron Efficiency in Oilseed Rape

    Institute of Scientific and Technical Information of China (English)

    SHI Lei; WANG Yun-Hua; NIAN Fu-Zhao; LU Jian-Wei; MENG Jin-Ling; XU Fang-Sen

    2009-01-01

    Field experiments were conducted to study the inheritance of boron efficiency in oilseed rape (Brassica napus L.) by evaluating the boron (B) efficiency coefficient (BEC,the ratio of the seed yield at below the critical boron level to that at the boron-sufficient level) with 657 F2:3 fines of a population derived from a cross between a B-efficient cultivar,Qingyou 10,and a B-inefficient cultivar,Bakow.Qingyou i0 had high BEC as well as high seed yield at low available soil B.On the contrary,Bakow produced low seed yield at low B status.Boron deficiency decreased the seed yield of the F2:3 lines to different extents and the distribution of BEC of the population showed a bimodal pattern.When the 657 F2:3 lines were grouped into B-efficient lines and B-inefficient lines according to their BEC,the ratio of B-efficient lines to B-inefficient lines fitted the expected ratio (3:1),indicating that one major gene controlled the B-efficiency trait.127 F2:3 lines selected from the population at random,with distribution of BEC similar to that of the overall population,were used to identify the target region for fine mapping of the boron efficiency gene.

  9. Innovative boron nitride-doped propellants

    Directory of Open Access Journals (Sweden)

    Thelma Manning

    2016-04-01

    Full Text Available The U.S. military has a need for more powerful propellants with balanced/stoichiometric amounts of fuel and oxidants. However, balanced and more powerful propellants lead to accelerated gun barrel erosion and markedly shortened useful barrel life. Boron nitride (BN is an interesting potential additive for propellants that could reduce gun wear effects in advanced propellants (US patent pending 2015-026P. Hexagonal boron nitride is a good lubricant that can provide wear resistance and lower flame temperatures for gun barrels. Further, boron can dope steel, which drastically improves its strength and wear resistance, and can block the formation of softer carbides. A scalable synthesis method for producing boron nitride nano-particles that can be readily dispersed into propellants has been developed. Even dispersion of the nano-particles in a double-base propellant has been demonstrated using a solvent-based processing approach. Stability of a composite propellant with the BN additive was verified. In this paper, results from propellant testing of boron nitride nano-composite propellants are presented, including closed bomb and wear and erosion testing. Detailed characterization of the erosion tester substrates before and after firing was obtained by electron microscopy, inductively coupled plasma and x-ray photoelectron spectroscopy. This promising boron nitride additive shows the ability to improve gun wear and erosion resistance without any destabilizing effects to the propellant. Potential applications could include less erosive propellants in propellant ammunition for large, medium and small diameter fire arms.

  10. Innovative boron nitride-doped propellants

    Institute of Scientific and Technical Information of China (English)

    Thelma MANNING; Henry GRAU; Paul MATTER; Michael BEACHY; Christopher HOLT; Samuel SOPOK; Richard FIELD; Kenneth KLINGAMAN; Michael FAIR; John BOLOGNINI; Robin CROWNOVER; Carlton P. ADAM; Viral PANCHAL; Eugene ROZUMOV

    2016-01-01

    The U.S. military has a need for more powerful propellants with balanced/stoichiometric amounts of fuel and oxidants. However, balanced and more powerful propellants lead to accelerated gun barrel erosion and markedly shortened useful barrel life. Boron nitride (BN) is an interesting potential additive for propellants that could reduce gun wear effects in advanced propellants (US patent pending 2015-026P). Hexagonal boron nitride is a good lubricant that can provide wear resistance and lower flame temperatures for gun barrels. Further, boron can dope steel, which drastically improves its strength and wear resistance, and can block the formation of softer carbides. A scalable synthesis method for producing boron nitride nano-particles that can be readily dispersed into propellants has been developed. Even dispersion of the nano-particles in a double-base propellant has been demonstrated using a solvent-based processing approach. Stability of a composite propellant with the BN additive was verified. In this paper, results from propellant testing of boron nitride nano-composite propellants are presented, including closed bomb and wear and erosion testing. Detailed characterization of the erosion tester substrates before and after firing was obtained by electron microscopy, inductively coupled plasma and x-ray photoelectron spectroscopy. This promising boron nitride additive shows the ability to improve gun wear and erosion resistance without any destabilizing effects to the propellant. Potential applications could include less erosive propellants in propellant ammunition for large, medium and small diameter fire arms.

  11. Boronization of Russian tokamaks from carborane precursors

    International Nuclear Information System (INIS)

    A new and cheap boronization technique using the nontoxic and nonexplosive solid substance carborane has been developed and successfully applied to the Russian tokamaks T-11M, T-3M, T-10 and TUMAN-3. The glow discharge in a mixture of He and carborane vapor produced the amorphous B/C coating with the B/C ratio varied from 2.0-3.7. The deposition rate was about 150 nm/h. The primary effect of boronization was a significant reduction of the impurity influx and the plasma impurity contamination, a sharp decrease of the plasma radiated power, and a decrease of the effective charge. Boronization strongly suppressed the impurity influx caused by additional plasma heating. ECR- and ICR-heating as well as ECR current drive were more effective in boronized vessels. Boronization resulted in a significant extension of the Ne- and q-region of stable tokamak operation. The density limit rose strongly. In Ohmic H-mode energy confinement time increased significantly (by a factor of 2) after boronization. It rose linearly with plasma current Ip and was 10 times higher than Neo-Alcator time at maximum current. ((orig.))

  12. Methyl bromide cycling in a warm-core eddy of the North Atlantic Ocean

    OpenAIRE

    Yvon-Lewis, SA; Butler, JH; Saltzman, Es; Matrai, PA; King, DB; R. Tokarczyk; Moore, RM; Zhang, JZ

    2002-01-01

    We conducted a detailed investigation of the evolution of methyl bromide concentrations, degradation rates, and ventilation rates for 26 days in a naturally contained, warm-core eddy of the North Atlantic Ocean. This is the first study of the oceanic cycling of methyl bromide in a natural, contained system with a complete suite of supporting measurements of physical and chemical variables. Methyl bromide concentrations in the mixed layer ranged from 2.3 to 4.2 nmol m−3, degradation rates rang...

  13. Synthesis and properties of low-carbon boron carbides

    International Nuclear Information System (INIS)

    This paper reports on the production of boron carbides of low carbon content (3 and CCl4 at 1273-1673 K in a chemical vapor deposition (CVD) reactor. Transmission electron microscopy (TEM) revealed that phase separation had occurred, and tetragonal boron carbide was formed along with β-boron or α-boron carbide under carbon-depleted gas-phase conditions. At temperatures greater than 1390 degrees C, graphite substrates served as a carbon source, affecting the phases present. A microstructure typical of CVD-produced α-boron carbide was observed. Plan view TEM of tetragonal boron carbide revealed a blocklike structure

  14. Development of magnetic resonance technology for noninvasive boron quantification

    International Nuclear Information System (INIS)

    Boron magnetic resonance imaging (MRI) and spectroscopy (MRS) were developed in support of the noninvasive boron quantification task of the Idaho National Engineering Laboratory (INEL) Power Burst Facility/Boron Neutron Capture Therapy (PBF/BNCT) program. The hardware and software described in this report are modifications specific to a GE Signa trademark MRI system, release 3.X and are necessary for boron magnetic resonance operation. The technology developed in this task has been applied to obtaining animal pharmacokinetic data of boron compounds (drug time response) and the in-vivo localization of boron in animal tissue noninvasively. 9 refs., 21 figs

  15. B-10 enriched boric acid, bromide, and heat as tracers of recycled groundwater flow near managed aquifer recharge operations

    Science.gov (United States)

    Clark, J. F.; Becker, T.; Johnson, T. A.

    2013-12-01

    Recycling wastewater for potable and nonpotable use by artificially recharging aquifers is a decades-old but increasingly popular practice. Natural attenuation processes in the subsurface, known as soil aquifer treatment (SAT), purify recycled water during recharge and subsequent groundwater flow. Travel time criteria are often used to regulate managed aquifer recharge (MAR) operations. California state draft regulations currently gives preference to groundwater tracers to quantify underground residence time, with a target retention time of >6 months from infiltration to drinking water extraction for surface spreading projects using tertiary treated wastewater (less time may be possible if full advanced treated water is utilized). In the past sulfur hexafluoride, a very strong greenhouse gas, has been the principle deliberate tracer for this work. However, its emission has recently become regulated in California and new tracers are needed. Here, two prospective tracers are evaluated: boron-10 (B-10), the least abundant boron isotope, and heat (with recharging water naturally warmed at the sewage treatment plants and in surface-spreading basins). An additional deliberate tracer, bromide (Br), which is a well-studied conservative tracer, was released as a control. Tracer injection occurred at the San Gabriel Spreading Grounds research test basin in Los Angeles County, CA, USA. The basin was constructed and characterized by the US Geological Survey in the mid-1990s. Recycled wastewater was piped directly to this basin at a known rate (about 1.5 m3/day). Down gradient from the test basin are nine high quality monitoring wells in a line that extends from the center of the basin to 150 m down gradient. All of the wells were equipped with temperature loggers that recorded groundwater temperatures every hour with an accuracy of one thousandth of a degree. The pre-experiment expected arrival times ranged from less than one day to six months. Arrival of Br was always

  16. A novel method of boron delivery using sodium iodide symporter for boron neutron capture therapy

    International Nuclear Information System (INIS)

    Boron Neutron Capture Therapy (BNCT) effectiveness depends on the preferential sequestration of boron in cancer cells relative to normal tissue cells. We present a novel strategy for sequestering boron using an adenovirus expressing the sodium iodide symporter (NIS). Human glioma grown subcutaneously in athymic mice and orthotopic rat brain tumors were transfected with NIS using a direct tumor injection of adenovirus. Boron bound as sodium tetrafluoroborate (NaBF4) was administered systemically several days after transfection. Tumors were excised hours later and assessed for boron concentration using inductively coupled plasma atomic emission spectroscopy. In the human glioma transfected with NIS, boron concentration was more than 10 fold higher with 100 mg/kg of NaBF4, compared to tumor not transfected. In the orthotopic tumor model, the presence of NIS conferred almost 4 times the boron concentration in rat tumors transfected with human virus compared with contralateral normal brain not transfected. We conclude that adenovirus expressing NIS has the potential to be used as a novel boron delivery agent and should be explored for future clinical applications. (author)

  17. Spectromicroscopy of boron for the optimization of boron neutron capture therapy (BNCT) for cancer

    International Nuclear Information System (INIS)

    We used synchrotron spectromicroscopy to study the microscopic distribution of boron in rat brain tumour and healthy tissue in the field of boron neutron capture therapy (BNCT). The success of this experimental cancer therapy depends on the preferential uptake of 10B in tumour cells after injection of a boron compound (in our case B12H11SH, or BSH). With the Mephisto (microscope a emission de photoelectrons par illumination synchrotronique de type onduleur) spectromicroscope, high-magnification imaging and chemical analysis was performed on brain tissue sections from a rat carrying an implanted brain tumour and the results were compared with inductively coupled plasma-atomic emission spectroscopy (ICP-AES) detection of boron in bulk tissue. Boron was found to have been taken up more favourably by regions of tumour rather than healthy tissue, but the resulting boron distribution in the tumour was inhomogeneous. The results demonstrate that Mephisto can perform microchemical analysis of tissue sections, detect and localize the presence of boron with submicron spatial resolution. The application of this technique to boron in brain tissue can therefore be used to evaluate the current efforts to optimize BNC therapy. (author)

  18. Proceedings of workshop on 'boron science and boron neutron capture therapy'

    Energy Technology Data Exchange (ETDEWEB)

    Kitaoka, Y. [ed.

    1998-12-01

    This volume contains the abstracts and programs of the 8th (1996), 9th (1997) and 10th (1998) of the workshop on 'the Boron Science and Boron Neutron Capture Therapy' and the recent progress reports especially subscribed. The 11 of the presented papers are indexed individually. (J.P.N.)

  19. A quantitative comparison between electrocoagulation and chemical coagulation for boron removal from boron-containing solution

    Energy Technology Data Exchange (ETDEWEB)

    Yilmaz, A. Erdem [Atatuerk University, Faculty of Engineering, Department of Environmental Engineering, 25240 Erzurum (Turkey)], E-mail: aerdemy@atauni.edu.tr; Boncukcuoglu, Recep [Atatuerk University, Faculty of Engineering, Department of Environmental Engineering, 25240 Erzurum (Turkey); Kocakerim, M. Muhtar [Atatuerk University, Faculty of Engineering, Department of Chemical Engineering, 25240 Erzurum (Turkey)

    2007-10-22

    This paper provides a quantitative comparison of electrocoagulation and chemical coagulation approaches based on boron removal. Electrocoagulation process delivers the coagulant in situ as the sacrificial anode corrodes, due to a fixed current density, while the simultaneous evolution of hydrogen at the cathode allows for pollutant removal by flotation. By comparison, conventional chemical coagulation typically adds a salt of the coagulant, with settling providing the primary pollutant removal path. Chemical coagulation was carried out via jar tests using aluminum chloride. Comparison was done with the same amount of coagulant between electrocoagulation and chemical coagulation processes. Boron removal obtained was higher with electrocoagulation process. In addition, it was seen that chemical coagulation has any effect for boron removal from boron-containing solution. At optimum conditions (e.g. pH 8.0 and aluminum dose of 7.45 g/L), boron removal efficiencies for electrocoagulation and chemical coagulation were 94.0% and 24.0%, respectively.

  20. A quantitative comparison between electrocoagulation and chemical coagulation for boron removal from boron-containing solution

    International Nuclear Information System (INIS)

    This paper provides a quantitative comparison of electrocoagulation and chemical coagulation approaches based on boron removal. Electrocoagulation process delivers the coagulant in situ as the sacrificial anode corrodes, due to a fixed current density, while the simultaneous evolution of hydrogen at the cathode allows for pollutant removal by flotation. By comparison, conventional chemical coagulation typically adds a salt of the coagulant, with settling providing the primary pollutant removal path. Chemical coagulation was carried out via jar tests using aluminum chloride. Comparison was done with the same amount of coagulant between electrocoagulation and chemical coagulation processes. Boron removal obtained was higher with electrocoagulation process. In addition, it was seen that chemical coagulation has any effect for boron removal from boron-containing solution. At optimum conditions (e.g. pH 8.0 and aluminum dose of 7.45 g/L), boron removal efficiencies for electrocoagulation and chemical coagulation were 94.0% and 24.0%, respectively

  1. Ceramic silicon-boron-carbon fibers from organic silicon-boron-polymers

    Science.gov (United States)

    Riccitiello, Salvatore R. (Inventor); Hsu, Ming-Ta S. (Inventor); Chen, Timothy S. (Inventor)

    1993-01-01

    Novel high strength ceramic fibers derived from boron, silicon, and carbon organic precursor polymers are discussed. The ceramic fibers are thermally stable up to and beyond 1200 C in air. The method of preparation of the boron-silicon-carbon fibers from a low oxygen content organosilicon boron precursor polymer of the general formula Si(R2)BR(sup 1) includes melt-spinning, crosslinking, and pyrolysis. Specifically, the crosslinked (or cured) precursor organic polymer fibers do not melt or deform during pyrolysis to form the silicon-boron-carbon ceramic fiber. These novel silicon-boron-carbon ceramic fibers are useful in high temperature applications because they retain tensile and other properties up to 1200 C, from 1200 to 1300 C, and in some cases higher than 1300 C.

  2. Absorber performance of a water/lithium-bromide absorption chiller

    Energy Technology Data Exchange (ETDEWEB)

    Xie Guozhen [Beijing University of Civil Engineering and Architecture, Beijing 100044 (China)], E-mail: xieguozhen@bucea.edu.cn; Sheng Guogang [Beijing University of Civil Engineering and Architecture, Beijing 100044 (China); Bansal, Pradeep Kumar [Department of Mechanical Engineering, The University of Auckland, Private Bag 92019 (New Zealand); Li, Guang [Beijing University of Civil Engineering and Architecture, Beijing 100044 (China)

    2008-09-15

    An absorber is one of the most important components of a lithium-bromide absorption chiller (LBAC) as its absorbing characteristics directly influence the performance of the whole chiller. It has been indicated that the absorbing efficiency and cooling capacity could be improved by increasing the solution concentration. In this paper, based on the mechanism of falling film absorption on horizontal tubes, the theoretical models of falling film absorption on horizontal tubes have been established. A series of programs used for computing the theoretical mathematical models, including simulation of LBAC cycle and falling film absorption, have been programmed. The models have been validated reasonably by the experimental data. The results show that the cooling capacity of the LBAC varies in parabola shape of curve with the solution concentration from 52.5% to 58.5%, and that the best coefficient of performance (COP) occurs at concentration of 57%. The investigation proposes the absorbing process of sub-steady thermodynamic equilibrium for the duality solution under increase absorbing pressure.

  3. Absorber performance of a water/lithium-bromide absorption chiller

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Guozhen; Sheng, Guogang; Li, Guang [Beijing University of Civil Engineering and Architecture, Beijing 100044 (China); Bansal, Pradeep Kumar [Department of Mechanical Engineering, The University of Auckland, Private Bag 92019 (New Zealand)

    2008-09-15

    An absorber is one of the most important components of a lithium-bromide absorption chiller (LBAC) as its absorbing characteristics directly influence the performance of the whole chiller. It has been indicated that the absorbing efficiency and cooling capacity could be improved by increasing the solution concentration. In this paper, based on the mechanism of falling film absorption on horizontal tubes, the theoretical models of falling film absorption on horizontal tubes have been established. A series of programs used for computing the theoretical mathematical models, including simulation of LBAC cycle and falling film absorption, have been programmed. The models have been validated reasonably by the experimental data. The results show that the cooling capacity of the LBAC varies in parabola shape of curve with the solution concentration from 52.5% to 58.5%, and that the best coefficient of performance (COP) occurs at concentration of 57%. The investigation proposes the absorbing process of sub-steady thermodynamic equilibrium for the duality solution under increase absorbing pressure. (author)

  4. Structural and electronic properties of Diisopropylammonium bromide molecular ferroelectric crystal

    Science.gov (United States)

    Alsaad, A.; Qattan, I. A.; Ahmad, A. A.; Al-Aqtash, N.; Sabirianov, R. F.

    2015-10-01

    We report the results of ab-initio calculations based on Generalized Gradient Approximation (GGA) and hybrid functional (HSE06) of electronic band structure, density of states and partial density of states to get a deep insight into structural and electronic properties of P21 ferroelectric phase of Diisopropylammonium Bromide molecular crystal (DIPAB). We found that the optical band gap of the polar phase of DIPAB is ∼ 5 eV confirming it as a good dielectric. Examination of the density of states and partial density of states reveal that the valence band maximum is mainly composed of bromine 4p orbitals and the conduction band minimum is dominated by carbon 2p, carbon 2s, and nitrogen 2s orbitals. A unique aspect of P21 ferroelectric phase is the permanent dipole within the material. We found that P21 DIPAB has a spontaneous polarization of 22.64 consistent with recent findings which make it good candidate for the creation of ferroelectric tunneling junctions (FTJs) which have the potential to be used as memory devices.

  5. Chloride, bromide and iodide scintillators with europium doping

    Science.gov (United States)

    Zhuravleva, Mariya; Yang, Kan

    2014-08-26

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

  6. 4-Bromophenacyl bromide specifically inhibits rhoptry secretion during Toxoplasma invasion.

    Science.gov (United States)

    Ravindran, Sandeep; Lodoen, Melissa B; Verhelst, Steven H L; Bogyo, Matthew; Boothroyd, John C

    2009-01-01

    Toxoplasma gondii is a eukaryotic parasite of the phylum Apicomplexa that is able to infect a wide variety of host cells. During its active invasion process it secretes proteins from discrete secretory organelles: the micronemes, rhoptries and dense granules. Although a number of rhoptry proteins have been shown to be involved in important interactions with the host cell, very little is known about the mechanism of secretion of any Toxoplasma protein into the host cell. We used a chemical inhibitor of phospholipase A2s, 4-bromophenacyl bromide (4-BPB), to look at the role of such lipases in the secretion of Toxoplasma proteins. We found that 4-BPB was a potent inhibitor of rhoptry secretion in Toxoplasma invasion. This drug specifically blocked rhoptry secretion but not microneme secretion, thus effectively showing that the two processes can be de-coupled. It affected parasite motility and invasion, but not attachment or egress. Using propargyl- or azido-derivatives of the drug (so-called click chemistry derivatives) and a series of 4-BPB-resistant mutants, we found that the drug has a very large number of target proteins in the parasite that are involved in at least two key steps: invasion and intracellular growth. This potent compound, the modified "click-chemistry" forms of it, and the resistant mutants should serve as useful tools to further study the processes of Toxoplasma early invasion, in general, and rhoptry secretion, in particular. PMID:19956582

  7. Organomontmorillonites Modified with 2-Methacryloyloxy Ethyl Alkyl Dimethyl Ammonium Bromide

    Institute of Scientific and Technical Information of China (English)

    WANG Jian-quan; WU Wen-hui

    2007-01-01

    Organomontmorillonites (organo-MMT) were synthesized by means of montmorillonites (MMT) modified with a series of 2-methacryloyloxy ethyl alkyl dimethyl ammonium bromide (MAAB) having different alkyl chain lengths as cationic surfactants through a cationic exchanging reaction, and were characterized by FTIR, TG, elemental analysis, and XRD. The microenvironment of the organic interlayer such as the orientation and arrangement of the alkyl chains of MAAB, as well as the properties of nanocomposite hydrogels, were also investigated. The amount of organic components absorbed on interlayer and the basal spacing of organo-MMT both increase with the increasing of alkyl length of MAAB. When carbon number of alkyl chain is in the region of 8 to 14, the alkyl chains between layers would adopt a disordered gauche conformation; while the carbon number is 16, an ordered all-trans conformation with a vertical orientation would be found together with the disordered gauche conformation according to the results of XRD and FTIR. Due to the difference of microenvironment of organic interlayer, the Young's moduli of the nanocomposite hydrogels increased as the alkyl chains of MAAB became longer.

  8. Evaluation of Alkali Bromide Salts for Potential Pyrochemical Applications

    Energy Technology Data Exchange (ETDEWEB)

    Prabhat K. Tripathy; Steven D. Herrmann; Guy L. Fredrickson; Tedd E. Lister; Toni Y. Gutknecht

    2013-10-01

    Transient techniques were employed to study the electrochemical behavior, reduction mechanism and transport properties of REBr3 (RE - La, Nd and Gd) in pure LiBr, LiBr-KBr (eutectic) and LiBr-KBr-CsBr (eutectic) melts. Gd(III) showed a reversible single step soluble-insoluble exchange phenomenon in LiBr melt at 973K. Although La (III), Nd(III) and Gd(III) ions showed reversible behavior in eutectic LiBr-KBr melts, these ions showed a combination of temperature dependent reversible and pseudo-reversible behavior. While both La(III) and Gd(III) showed one step reduction, the reduction of Nd(III) was observed to be a two step process. La metal could be electrodeposited from the ternary electrolyte at a temperature of 673K. Various electrochemical measurements suggest that both binary and ternary bromide melts can potentially be used to electrodeposit high purity RE metals at comparatively lower operating temperatures.

  9. Accommodation coefficient of HOBr on deliquescent sodium bromide aerosol particles

    Directory of Open Access Journals (Sweden)

    M. Wachsmuth

    2002-01-01

    Full Text Available Uptake of HOBr on sea salt aerosol, sea salt brine or ice is believed to be a key process providing a source of photolabile bromine (Br2 and sustaining ozone depletion cycles in the Arctic troposphere. In the present study, uptake of HOBr on sodium bromide (NaBr aerosol particles was investigated at an extremely low HOBr concentration of 300 cm-3 using the short-lived radioactive isotopes 83-86Br. Under these conditions, at maximum one HOBr molecule was taken up per particle. The rate of uptake was clearly limited by the mass accommodation coefficient, which was calculated to be 0.6 ± 0.2. This value is a factor of 10 larger than estimates used in earlier models. The atmospheric implications are discussed using the box model "MOCCA'', showing that the increase of the accommodation coefficient of HOBr by a factor of 10 only slightly affects net ozone loss, but significantly increases chlorine release.

  10. Improved spectrometric characteristics of thallium bromide nuclear radiation detectors

    CERN Document Server

    Hitomi, K; Shoji, T; Suehiro, T; Hiratate, Y

    1999-01-01

    Thallium bromide (TlBr) is a compound semiconductor with a high atomic number and wide band gap. In this study, nuclear radiation detectors have been fabricated from the TlBr crystals. The TlBr crystals were grown by the horizontal travelling molten zone (TMZ) method using the materials purified by many pass zone refining. The crystals were characterized by measuring the resistivity, the mobility-lifetime (mu tau) product and the energy required to create an electron-hole pair (the epsilon value). Improved energy resolution has been obtained by the TlBr radiation detectors. At room temperature the full-width at half-maximum (FWHM) for the 59.5, 122 and 662 keV gamma-ray photo peak obtained from the detectors were 3.3, 8.8 and 29.5 keV, respectively. By comparing the saturated peak position of the TlBr detector with that of the CdTe detector, the epsilon value has been estimated to be about 5.85 eV for the TlBr crystal.

  11. Water-lithium bromide double-effect absorption cooling analysis

    Energy Technology Data Exchange (ETDEWEB)

    Vliet, G.C.; Lawson, M.B.; Lithgow, R.A.

    1980-12-01

    A numerical model was developed for the transient simulation of the double-effect, water-lithium bromide absorption cooling machine, and the use of the model to determine the effect of the various design and input variables on the absorption unit performance. The performance parameters considered were coefficient of performance and cooling capacity. The sensitivity analysis was performed by selecting a nominal condition and determining performance sensitivity for each variable with others held constant. The variables considered in the study include source hot water, cooling water, and chilled water temperatures; source hot water, cooling water, and chilled water flow rates; solution circulation rate; heat exchanger areas; pressure drop between evaporator and absorber; solution pump characteristics; and refrigerant flow control methods. The performance sensitivity study indicated in particular that the distribution of heat exchanger area among the various (seven) heat exchange components is a very-important design consideration. Moreover, it indicated that the method of flow control of the first effect refrigerant vapor through the second effect is a critical design feature when absorption units operate over a significant range of cooling capacity. The model was used to predict the performance of the Trane absorption unit with fairly good accuracy.

  12. Nanocapsules of perfluorooctyl bromide for theranostics: from formulation to targeting

    Science.gov (United States)

    Diou, O.; Fattal, E.; Payen, T.; Bridal, S. L.; Valette, J.; Tsapis, N.

    2014-03-01

    The need to detect cancer at its early stages, as well as, to deliver chemotherapy to targeted site motivates many researchers to build theranostic platforms which combine diagnostic and therapy. Among imaging modalities, ultrasonography and Magnetic Resonance Imaging (MRI) are widely available, non invasive and complement each other. Both techniques often require the use of contrast agents. We have developed nanocapsules of perfluorooctyl bromide as dual contrast agent for both imaging modalities. The soft, amorphous polymer shell provides echogenicity, while the high-density perfluorinated liquid core allows detection by 19F MRI. We have used a shell of poly(lactide-co-glycolide) (PLGA) since this polymer is biodegradable, biocompatible and can be loaded with drugs. These capsules were shown to be efficient in vitro as contrast agents for both 19F MRI and ultrasonography. In addition, for in vivo applications a poly(ethyleneglycol) (PEG) coating promotes stability and prolonged circulation. Being stealth, nanocapsule can accumulate passively into implanted tumors by the EPR effect. We will present nanocapsule formulation and characterization, and will show promising in vivo results obtained for both ultrasonography and 19F MRI.

  13. Boron-11 NMR spectroscopy of excised mouse tissues after infusion of boron compound used in neutron capture therapy

    International Nuclear Information System (INIS)

    Boron neutron capture therapy (BNCT) is based on selective boron uptake by the tumor and in situ activation by neutron beam. The authors propose the use of B-11 MR spectroscopy to noninvasively study boron uptake in animal tumor models. Sodium mercaptoundeca-hydrododecaborate was infused into female BALB/cJ mice and liver, brain, spleen, kidney, and tumor tissues were excised for MR (27.4MHz) and total boron content measurements. Boron-11 was easily detectable in tumor, liver, spleen, and skin. The results gave a very good correlation (correlation coefficient of .997) between B-11 MR measurements and total boron content of excised mouse tissues

  14. A comparison of the effect of intranasal desmopressin and intramuscular hyoscine N-butyl bromide combination with intramuscular hyoscine N-butyl bromide alone in acute renal colic

    Directory of Open Access Journals (Sweden)

    Abdol-Reza Kheirollahi

    2010-01-01

    Full Text Available Background: Patients with acute renal colic usually require immediate diagnosis and treatment. In this clinical trial analgesic effect of hyoscine N-butyl bromide and desmopressin combination in comparison with hyoscine N-butyl bromide alone in patients with acute renal colic induced by urinary stones was assessed. Methods: The study included 114 patients randomly allocated in two groups (A and B. Patients in group A received 20 mg intramuscular hyoscine N-butyl bromide at admission time and patients in group B received 20 μg of intranasal desmopressin in combination with 20 mg intramuscular hyoscine N-butyl bromide. A visual analogue scale (VAS; a 10-cm horizontal scale ranging from "zero or no pain" to "10 or unbearable pain" was hired to assess the patients′ pain severity at baseline, 30 and 60 minutes after the treatments. Results: On admission, the pain level was similar in both groups (group A: 8.95 ± 0.11 and group B: 8.95 ± 0.12. In group A, the mean of pain level showed a decrease after 30 minutes (group A: 7.26 ± 0.25 and group B: 5.95 ± 0.28 but further decreasing did not occur; however in group B, the pain consistently decreased and the mean after 60 minutes was significantly decreased (group A: 6.80 ± 0.31 and group B: 3.71 ± 0.31. No side effects were detected in this study. Conclusions: The combination of hyoscine N-butyl bromide and desmopressin is more effective than hyoscine N-butyl bromide alone in patients with renal colic. Further studies are recommended to validate these findings and compare the different doses of desmopressin.

  15. Radioactive bromide partition test in the diagnosis of tubercular meningitis in children

    International Nuclear Information System (INIS)

    Radioactive 82bromide (0.64 μCi/kg) was administered orally to 52 children in the age group of 0-12 yr, 41 patients with suspected tubercular meningitis (TBM) and 11 with non-tubercular meningitis. The bromide activity in the serum and CSF were obtained at 48 h. A serum to CSF bromide partition ratio (BPR) of 1.9 and below was highly specific for TBM, and was seen in 38 of 41 patients, this included the 11 patients where the diagnosis of tuberculosis was proved by AFB isolation and/or histopathology. In the non-tubercular group BPR was above 1.9 in all the patients with no false positivity. The present study re-affirms the value of bromide partition test in the diagnosis of tubercular meningitis. (author)

  16. Electrochemical removal of bromide and reduction of THM formation potential in drinking water.

    Science.gov (United States)

    Kimbrough, David Eugene; Suffet, I H

    2002-11-01

    Trihalomethanes (THMs), a by-product of the chlorination of natural waters containing dissolved organic carbon and bromide, are the focus of considerable public health concern and regulation due to their potential as a carcinogen by ingestion. This paper presents a promising new water treatment process that lowers the concentration of bromide in drinking water and thus, lowers the THM formation potential. Bromide is oxidized by electrolysis to bromine and then the bromine apparently volatilized. The electrolyzed water, when chlorinated, produces measurably lower amounts of THMs and proportionately fewer brominated THMs, which are of greater public health concern than the chlorinated THMs. Removing bromide should also reduce the formation of other disinfection by-products such as bromate and haloacetic acids. PMID:12448534

  17. Plasmid DNA induces dodecyl triethyl ammonium bromide to aggregate into vesicle

    Institute of Scientific and Technical Information of China (English)

    Xiang Mei Ran; Xia Guo; Jia Tong Ding

    2012-01-01

    Single-chained cationic surfactant dodecyl triethyl ammonium bromide and plasmid DNA together can form vesicles once the concentration of plasmid DNA reaches a critical value (Ccvc).Bigger the size of plasmid DNA,higher the value of Ccvc.

  18. Stabilized thallium bromide radiation detectors and methods of making the same

    Energy Technology Data Exchange (ETDEWEB)

    Leao, Cedric Rocha; Lordi, Vincenzo

    2015-11-24

    According to one embodiment, a crystal includes thallium bromide (TlBr), one or more positively charged dopants, and one or more negatively charged dopants. According to another embodiment, a system includes a monolithic crystal including thallium bromide (TlBr), one or more positively charged dopants, and one or more negatively charged dopants; and a detector configured to detect a signal response of the crystal.

  19. Interaction of removal Ethidium Bromide with Carbon Nanotube: Equilibrium and Isotherm studies

    OpenAIRE

    Moradi, Omid; Norouzi, Mehdi; FAKHRI, Ali; Naddafi, Kazem

    2014-01-01

    Drinking water resources may be contaminated with Ethidium Bromide (EtBr) which is commonly used in molecular biology laboratories for DNA identification in electrophoresis. Carbon nanotubes are expected to play an important role in sensing, pollution treatment and separation techniques. In this study adsorption of Ethidium Bromide on single-walled carbon nanotubes (SWCNTs) and carboxylate group functionalized single-walled carbon nanotube (SWCNT-COOH) surfaces have been investigated by UV–vi...

  20. A case report of QT prolongation with glycopyrronium bromide in a patient with chronic tamoxifen use

    OpenAIRE

    Chiu, Michael H.; Al-Majed, Nawaf S.; Stubbins, Ryan; Pollmann, Dylan; Sandhu, Roopinder K.

    2016-01-01

    Background Glycopyrronium bromide has recently been approved as a once daily maintenance inhalation therapy for moderate to severe chronic obstructive pulmonary disease (COPD). Efficacy and safety trial data have found rare cases of significant QT prolongation. To our knowledge, we describe the first case report of QT prolongation >600 ms with initiation of glycopyrronium bromide in a real world setting. Case presentation A 78-year-old female with moderate COPD recently started on glycopyrron...

  1. Tribromoisocyanuric acid/triphenylphosphine: a new system for conversion of alcohols into alkyl bromides

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Vitor S.C. de; Mattos, Marcio C.S. de, E-mail: mmattos@iq.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Instituto de Quimica. Departamento de Quimica Organica

    2014-05-15

    An efficient and facile method has been developed for the conversion of alcohols into alkyl bromides under neutral conditions using tribromoisocyanuric acid and triphenylphosphine (molar ratio 1.0:0.7:2.0, alcohol/tribromoisocyanuric acid/triphenylphosphine) in dichloromethane at room temperature. This method can be applied for the conversion of primary, secondary, benzilic and allylic alcohols, and their corresponding bromides are obtained in 67-82 % yield. Tertiary alcohols do not react under these conditions. (author)

  2. Inhibition of methoxamine-induced bronchoconstriction by ipratropium bromide and disodium cromoglycate in asthmatic subjects.

    OpenAIRE

    Black, J.; Vincenc, K; Salome, C.

    1985-01-01

    We compared the effects of pretreatment with saline, ipratropium bromide, and disodium cromoglycate (DSCG) on bronchoconstriction induced by methoxamine--an alpha-adrenoceptor agonist, in asthmatic subjects. All 12 patients bronchoconstricted in response to methoxamine after saline. The PD20 (the dose of methoxamine causing a 20% fall in forced expiratory volume in 1 s [FEV1]) ranged from 0.3-18 mumol. Ipratropium bromide (200 micrograms administered by aerosol) significantly inhibited (P les...

  3. Corrosion Behavior of Austenitic and Duplex Stainless Steels in Lithium Bromide

    OpenAIRE

    Ayo Samuel AFOLABI; Alaneme, K.K.; Samson Oluwaseyi BADA

    2009-01-01

    The corrosion behavior of austenitic and duplex stainless steels in various concentrations of lithium, bromide solution was investigated by using the conventional weight loss measurement method. The results obtained show that corrosion of these steels occurred due to the aggressive bromide ion in the medium. Duplex stainless steel shows a greater resistance to corrosion than austenitic stainless steel in the medium. This was attributed to equal volume proportion of ferrite and austenite in th...

  4. Boron: out of the sky and onto the ground

    International Nuclear Information System (INIS)

    Now an accepted, engineered material for aerospace applications, boron is taking its place on the ground. Both current production applications, prototype (development) applications, and speculative applications abound. In the leisure product market, boron epoxy or boron aluminum has been used or tried in golf clubs (in combination with graphite epoxy or to reinforce aluminum or steel), in tennis racquets, in bicycles, racing shells, skis and skipoles, bows and arrows, and others. In the industrial area, boron has been used to reduce fatigue, increase stiffness, or for its abrasive properties. Textile machinery, honing tools, and cut off wheels or saws are among the applications. In the medical field, prosthetics and orthotic braces, wheel chairs, canes, and crutches are all good applications for boron. Applications for boron in transportation, construction, and heavy industry are also possible. The volume of boron used in these applications could have a major impact on prices, making boron composite parts cost competitive with conventional materials. (U.S.)

  5. 15th International Conference on Boron Chemistry (IMEBORON XV)

    Czech Academy of Sciences Publication Activity Database

    Grüner, Bohumír; Štíbr, Bohumil

    2015-01-01

    Roč. 87, č. 2 (2015), s. 121. ISSN 0033-4545 Institutional support: RVO:61388980 Keywords : boranes * boron * boron materials * carboranes * IMEBORON XV * medicinal chemistry Subject RIV: CA - Inorganic Chemistry

  6. Boron Removal in Seawater Reverse Osmosis System

    KAUST Repository

    Rahmawati, Karina

    2011-07-01

    Reverse osmosis successfully proves to remove more than 99% of solute in seawater, providing fresh water supply with satisfied quality. Due to some operational constraints, however, some trace contaminants removal, such as boron, cannot be achieved in one pass system. The stringent criterion for boron from World Health Organization (WHO) and Saudi Arabia local standard (0.5 mg/l) is hardly fulfilled by single pass sea water reverse osmosis (SWRO) plants. Some design processes have been proposed to deal with boron removal, but they are not economically efficient due to high energy and chemical consumption. The objective of this study was to study boron removal by different reverse osmosis membranes in two pH conditions, with and without antiscalant addition. Thus, it was expected to observe the possibility of operating single pass system and necessity to operate two pass system using low energy membrane. Five membrane samples were obtained from two different manufacturers. Three types of feed water pH were used, pH 8, pH 10, and pH 10 with antiscalant addition. Experiment was conducted in parallel to compare membrane performance from two manufacturers. Filtration was run with fully recycle mode for three days. Sample of permeate and feed were taken every 12 hours, and analyzed for their boron and TDS concentration. Membrane samples were also tested for their surface charge. The results showed that boron rejection increases as the feed pH increases. This was caused by dissociation of boric acid to negatively charged borate ion and more negatively charged membrane surface at elevated pH which enhance boron rejection. This study found that single pass reverse osmosis system, with and without elevating the pH, may not be possible to be applied because of two reasons. First, permeate quality in term of boron, does not fulfill WHO and local Saudi Arabia regulations. Second, severe scaling occurs due to operation in alkaline condition, since Ca and Mg concentration are

  7. Effect of ferric and bromide ions on the formation and speciation of disinfection byproducts during chlorination

    Institute of Scientific and Technical Information of China (English)

    Shaogang Liu; Zhiliang Zhu; Yanling Qiu; Jianfu Zhao

    2011-01-01

    The effects of ferric ion, pH, and bromide on the formation and distribution of disinfection byproducts (DBPs) during chlorination were studied. Two raw water samples from Huangpu River and Yangtze River, two typical drinking water sources of Shanghai, were used for the investigation. Compared with the samples from Huangpu River, the raw water samples from Yangtze River had lower content of total organic carbon (TOC) and ferric ions, but higher bromide concentrations. Under controlled chlorination conditions,four trihalomethanes (THMs), nine haloacetic acids (HAAs), total organic halogen (TOX) and its halogen species fractions, including total organic chlorine (TOC1) and total organic bromide (TOBr), were determined. The results showed that co-existent ferric and bromide ions significantly promoted the formation of total THMs and HAAs for both raw water samples. Higher concentration of bromide ions significantly changed the speciation of the formed THMs and HAAs. There was an obvious shift to brominated species,which might result in a more adverse influence on the safety of drinking water. The results also indicated that high levels of bromide ions in raw water samples produced higher percentages of unknown TOBr.

  8. Bromine and bromide content in soils: Analytical approach from total reflection X-ray fluorescence spectrometry.

    Science.gov (United States)

    Gallardo, Helena; Queralt, Ignasi; Tapias, Josefina; Candela, Lucila; Margui, Eva

    2016-08-01

    Monitoring total bromine and bromide concentrations in soils is significant in many environmental studies. Thus fast analytical methodologies that entail simple sample preparation and low-cost analyses are desired. In the present work, the possibilities and drawbacks of low-power total reflection X-ray fluorescence spectrometry (TXRF) for the determination of total bromine and bromide contents in soils were evaluated. The direct analysis of a solid suspension using 20 mg of fine ground soil (water soil extracts. In this case, the TXRF analysis can be directly performed by depositing 10 μL of the internal standardized soil extract sample on a quartz glass reflector in a measuring time of 1500 s. The bromide limit of detection by this approach was 10 μg L(-1). Good agreement was obtained between the TXRF results for the total bromine and bromide determinations in soils and those obtained by other popular analytical techniques, e.g. energy dispersive X-ray fluorescence spectrometry (total bromine) and ionic chromatography (bromide). As a study case, the TXRF method was applied to study bromine accumulation in two agricultural soils fumigated with a methyl bromide pesticide and irrigated with regenerated waste water. PMID:27179429

  9. Electrochemical Recognition of Metalloproteins by Bromide-modified Silver Electrode - A New Method

    Directory of Open Access Journals (Sweden)

    Abbas Ali Rostami

    2007-07-01

    Full Text Available A bromide–modified silver electrode is reported, in the present study, to catalyzethe redox reactions of metalloproteins. This study describes that the bromide ions showvery good redox behavior with silver electrode. The cathodic and anodic peak potentialswere related to the concentration of bromide ions involved in making bromide-modifiedsilver electrode. The electrode reaction in the bromine solution was a diffusion-controlledprocess. Positive potential shift of the bromide ions was seen when different proteins wereadded to the solution using a silver electrode. New cathodic and anodic peaks wereobserved at different potential ranges for myoglobin, cytochrome c and catalase. A linearlyincreasing cathodic peak current of bromide ions was seen when the concentration ofsuperoxide dismutase was increased in the test solution. However, no change for albuminwas observed when its concentration was increased in the test solution. Present data provesour methodology as an easy-to-use analysis for comparing the redox potentials of differentmetalloproteins and differentiating the metallo- from non-metalloproteins. In this study, weintroduced an interesting method for bio-electrochemical analyses.

  10. Partial molar volume and isentropic compressibility of symmetrical and asymmetrical quaternary ammonium bromides in aqueous solution

    International Nuclear Information System (INIS)

    Highlights: • Structural effects of the cations on surrounding water molecules are discussed. • Alkyl-chain geometry determines the hydration of Bu4N+ isomers. • The “compactness” in the hydration shells varies significantly among the isomers. - Abstract: Values of apparent molar volume and isentropic compressibility of symmetric and asymmetric isomers of tetrabutylammonium bromide, namely tetra-n-butylammonium bromide, tetra-iso-butylammonium bromide, tetra-sec-butylammonium bromide, di-n-butyl-di-iso-butylammonium bromide and di-n-butyl-di-sec-butylammonium bromide, in aqueous solution were determined from density and speed of sound measurements. These properties were obtained as a function of molal concentration within the range of 0.01 < m/mol · kg−1 < 0.1 covering temperatures from 278.15 ⩽ T/K ⩽ 293.15. The partial molar volumes and the apparent isentropic molar compressibility at infinite dilution were calculated and their dependence on temperature examined. The results show that cations with sec-butyl chains have larger structural volumes compared to those with iso-butyl chains. In addition, cations with sec-butyl chains induce smaller structural changes in their hydration shell than the others

  11. First gaseous boronization during pulsed discharge cleaning

    Energy Technology Data Exchange (ETDEWEB)

    Ko, J., E-mail: jinseok@nfri.re.kr [Department of Physics, University of Wisconsin, Madison, WI (United States); Den Hartog, D.J.; Goetz, J.A.; Weix, P.J.; Limbach, S.T. [Department of Physics, University of Wisconsin, Madison, WI (United States)

    2013-01-15

    The first successful gaseous boronization during a pulsed discharge is reported. Sublimation of o-carborane (C{sub 2}B{sub 10}H{sub 12}) combined with pulsed discharge plasmas with a repetition rate of 1 Hz is used to produce a hard boron-containing coating for reversed field pinch (RFP) plasmas in the Madison Symmetric Torus. X-ray photoelectron spectroscopy with Ar ion beam etching for silicon coupons installed at the plasma boundary shows about 60% boron concentration in the deposited layer. Both profilometer and scanning electron microscope analyses of the silicon coupons imply a strong toroidally non-uniform deposition depending on the location of the o-carborane injection. The layer thickness ranges from 50 to 300 nm. Ellipsometry calibrated with the profilometer results yields a refractive index of 2.2-2.3 for the films. The high refractive index implies that the coating is hard and has a well-ordered morphology. A reduction in wall recycling has consistently been observed after all boronization sessions. Comparison of the X-ray spectra in standard RFP plasmas before and after boronization indicates a slight decrease in the effective ionic charge.

  12. Boron isotope fractionation during brucite deposition from artificial seawater

    OpenAIRE

    J. Xiao; Xiao, Y. K.; Liu, C. Q.; Z. D. Jin

    2011-01-01

    Experiments involving boron incorporation into brucite (Mg(OH)2) from magnesium-free artificial seawater with pH values ranging from 9.5 to 13.0 were carried out to better understand the incorporation behavior of boron into brucite. The results show that both concentration of boron in deposited brucite ([B]d) and its boron partition coefficient (Kd) between deposited brucite and final seawater are controll...

  13. Characterization of boron carbide with an electron microprobe

    Science.gov (United States)

    Matteudi, G.; Ruste, J.

    1983-01-01

    Within the framework of a study of heterogeneous materials (Matteudi et al., 1971: Matteudi and Verchery, 1972) thin deposits of boron carbide were characterized. Experiments using an electronic probe microanalyzer to analyze solid boron carbide or boron carbide in the form of thick deposits are described. Quantitative results on boron and carbon are very close to those obtained when applying the Monte Carlo-type correction calculations.

  14. Technology of boron-containing polyphosphate fertilizer 'Phosphobor'

    International Nuclear Information System (INIS)

    A technology is developed for producing 'Phosphobor' fertilizer based on the rock phosphate weal (17-18% P2O5) with additions of boron-magnesium compound. Boron is part of polyphosphate fertilizer in the form of polymeric compounds of phosphorus and boron. Phosphorus and boron copolymers -boratophosphates - are easily formed in the process of polyphosphate fertilizers production, since borates undergo a mutual polycondensation reaction with phosphates. 8 refs., 1 fig

  15. Glass manufacturing process having boron and fluorine pollution abating features

    Energy Technology Data Exchange (ETDEWEB)

    Froberg, M.L.; Schroeder, C.F.

    1981-11-03

    Boron and/or fluorine values are reclaimed from a boron and/or fluorine laden gas stream emanating from a glass melter by means of a preheating bed of glass-forming batch agglomerates. The boron and/or fluorine values in such gases are first reacted with a boron and/or fluorine reactive material and the gases then conveyed into such a preheating bed to separate at least a portion of the reaction products.

  16. Glass manufacturing process having boron and fluorine pollution abating features

    International Nuclear Information System (INIS)

    Boron and/or fluorine values are reclaimed from a boron and/or fluorine laden gas stream emanating from a glass melter by means of a preheating bed of glass-forming batch agglomerates. The boron and/or fluorine values in such gases are first reacted with a boron and/or fluorine reactive material and the gases then conveyed into such a preheating bed to separate at least a portion of the reaction products

  17. Carbon isotope fractionation of methyl bromide during agricultural soil fumigations

    Science.gov (United States)

    Bill, M.; Miller, L.G.; Goldstein, Allen H.

    2002-01-01

    The isotopic composition of methyl bromide (CH3Br) has been suggested to be a potentially useful tracer for constraining the global CH3Br budget. In order to determine the carbon isotopic composition of CH3Br emitted from the most significant anthropogenic application (pre-plant fumigation) we directly measured the ??13C of CH3Br released during commercial fumigation. We also measured the isotopic fractionation associated with degradation in agricultural soil under typical field fumigation conditions. The isotopic composition of CH3Br collected in soil several hours after injection of the fumigant was -44.5??? and this value increased to -20.7??? over the following three days. The mean kinetic isotope effect (KIE) associated with degradation of CH3Br in agricultural soil (12???) was smaller than the reported value for methylotrophic bacterial strain IMB-1, isolated from previously fumigated agricultural soil, but was similar to methylotrophic bacterial strain CC495, isolated from a pristine forest litter zone. Using this fractionation associated with the degradation of CH3Br in agricultural soil and the mean ??13C of the industrially manufactured CH3Br (-54.4???), we calculate that the agricultural soil fumigation source has a carbon isotope signature that ranges from -52.8??? to -42.0???. Roughly 65% of industrially manufactured CH3Br is used for field fumigations. The remaining 35% is used for structural and post-harvest fumigations with a minor amount used during industrial chemical manufacturing. Assuming that the structural and post-harvest fumigation sources of CH3Br are emitted without substantial fractionation, we calculate that the ??13C of anthropogenically emitted CH3Br ranges from -53.2??? to -47.5???.

  18. Structure and scintillation of Eu2+-activated calcium bromide iodide

    International Nuclear Information System (INIS)

    We report the structure and scintillation properties of Eu2+-activated calcium bromide iodide. CaBr0.7I1.3 was the only composition that could be synthesized in the CaBr2–CaI2 system. The compound has an effective atomic number of 47 and crystallizes in a trigonal crystal system with the R-3 space group and a density of 3.93 g/cc. The structure is layered and contains Ca in an octahedral environment with the Br/I anions jointly occupying a single site. Eu2+-activated samples show an intense narrow emission, characteristic of the 5d–4f transition of Eu2+, when excited with UV or X-rays. The sample with 0.5% Eu shows a light output of 63,000 ph/MeV at 662 keV with 96% of the light emitted with a monoexponential decay time of 1332 ns. An energy resolution of 10.4% full width at half maximum (FWHM) has been achieved for 662 keV gamma rays at room temperature. - Highlights: • CaBr0.7I1.3 is the only composition that formed in the CaBr2–CaI2 system. • Crystallizes in a trigonal crystal system with the R-3 space group. • Eu2+-activation yields scintillator with bright blue emission centered at 465 nm. • Light output is 63,000 ph/MeV with 10.4% energy resolution at 662 keV. • Monoexponential decay time of 1332 ns

  19. Eudragit RS PO nanoparticles for sustained release of pyridostigmine bromide

    International Nuclear Information System (INIS)

    Pyridostigmine bromide (PB) is an inhibitor of cholinesterase, which is used in the treatment of myasthenia gravis and administered for protection against exposure to toxic nerve agents. Tests were done to investigate prolonging the half-life of PB and improving its release behavior. PB was loaded in nanoparticles (NPs) of Eudragit RS PO (Eu-RS) prepared using the technique of quasi emulsion solvent diffusion. Variables of output power of the sonicator, bath temperature and mixing time, were chosen as the optimization factors to obtain the minimum sized NPs. In addition, emulsions were tested at different ratios of drug-to-polymer by dynamic light scattering to determine size and zeta potential of NPs. UV-spectroscopy was used to determine PB content of the NPs. Drug-loaded NPs were characterized by scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectra. Results determined that mixing time had a significant impact on the size of Eu-RS NPs, but power output of sonicator and bath temperature had no significant effect. The particle size obtained at the optimum condition (power output of 70 W, bath temperature of 33 °C, and mixing time of 7 min) was less than 200 nm (optimum sizes were 138.9 and 179.5 nm for Eu-RS and PB-loaded Eu-RS NPs, respectively). The optimum PB-loaded Eu-RS NPs at the PB to Eu-RS weight ratio of 1–4 and 20 % of loaded PB released from the nanocarriers within 100 h

  20. Eudragit RS PO nanoparticles for sustained release of pyridostigmine bromide

    Energy Technology Data Exchange (ETDEWEB)

    Hoobakht, Fatemeh; Ganji, Fariba, E-mail: fganji@modares.ac.ir; Vasheghani-Farahani, Ebrahim [Tarbiat Modares University, Biomedical Engineering Group, Chemical Engineering Department (Iran, Islamic Republic of); Mousavi, Seyyed Mohammad [Tarbiat Modares University, Biotechnology Group, Chemical Engineering Department (Iran, Islamic Republic of)

    2013-09-15

    Pyridostigmine bromide (PB) is an inhibitor of cholinesterase, which is used in the treatment of myasthenia gravis and administered for protection against exposure to toxic nerve agents. Tests were done to investigate prolonging the half-life of PB and improving its release behavior. PB was loaded in nanoparticles (NPs) of Eudragit RS PO (Eu-RS) prepared using the technique of quasi emulsion solvent diffusion. Variables of output power of the sonicator, bath temperature and mixing time, were chosen as the optimization factors to obtain the minimum sized NPs. In addition, emulsions were tested at different ratios of drug-to-polymer by dynamic light scattering to determine size and zeta potential of NPs. UV-spectroscopy was used to determine PB content of the NPs. Drug-loaded NPs were characterized by scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectra. Results determined that mixing time had a significant impact on the size of Eu-RS NPs, but power output of sonicator and bath temperature had no significant effect. The particle size obtained at the optimum condition (power output of 70 W, bath temperature of 33 Degree-Sign C, and mixing time of 7 min) was less than 200 nm (optimum sizes were 138.9 and 179.5 nm for Eu-RS and PB-loaded Eu-RS NPs, respectively). The optimum PB-loaded Eu-RS NPs at the PB to Eu-RS weight ratio of 1-4 and 20 % of loaded PB released from the nanocarriers within 100 h.

  1. The use of lanthanum bromide detectors for nuclear safeguards applications

    International Nuclear Information System (INIS)

    Lanthanum Bromide (LaBr3) is a type of scintillation detector that has become commercially available recently. According to the manufacturer and studies conducted at a laboratory level, this new gamma-ray detector presents improved characteristics in comparison with traditional sodium iodine (NaI) detectors. Better energy resolution, relative efficiency and stability with temperature are some of the features that may impact positively the performance of the measurements made with this detector, which works at room temperature. Uranium enrichment measurements performed in the field is of special interest at nuclear fuel cycle facilities. Typical applications include quality control, U-235 inventory verification and nuclear safeguards. The Safeguards Laboratory of the Brazilian Nuclear Energy Commission (CNEN) and the Brazilian-Argentine Agency for Accounting and Control of Nuclear Materials (ABACC) have initiated the evaluation of the performance of a LaBr3 probe model BrilLanceCe 380 (B380) for U-235 enrichment determination in uranium compounds typically found in nuclear facilities under safeguards. This activity is routinely performed by national and international safeguards inspectors in both Brazilian and Argentine facilities. Depending on the characteristics of the material to be verified and the conditions at the measurement location, NaI or high-purity germanium detector (HPGe) are usually selected as the standard gamma-ray spectroscopic system for enrichment determination. This paper presents the conclusions of the initial studies jointly conducted by CNEN and ABACC regarding the use of a LaBr3 detector for enrichment determination, based on the comparison with NaI and HPGe typical performances. It also discusses the possibility to use this new gamma-ray detector as a standard technique for safeguards applications, compliant with national and international performance values. (author)

  2. The killing of African trypanosomes by ethidium bromide.

    Directory of Open Access Journals (Sweden)

    Arnab Roy Chowdhury

    Full Text Available Introduced in the 1950s, ethidium bromide (EB is still used as an anti-trypanosomal drug for African cattle although its mechanism of killing has been unclear and controversial. EB has long been known to cause loss of the mitochondrial genome, named kinetoplast DNA (kDNA, a giant network of interlocked minicircles and maxicircles. However, the existence of viable parasites lacking kDNA (dyskinetoplastic led many to think that kDNA loss could not be the mechanism of killing. When recent studies indicated that kDNA is indeed essential in bloodstream trypanosomes and that dyskinetoplastic cells survive only if they have a compensating mutation in the nuclear genome, we investigated the effect of EB on kDNA and its replication. We here report some remarkable effects of EB. Using EM and other techniques, we found that binding of EB to network minicircles is low, probably because of their association with proteins that prevent helix unwinding. In contrast, covalently-closed minicircles that had been released from the network for replication bind EB extensively, causing them, after isolation, to become highly supertwisted and to develop regions of left-handed Z-DNA (without EB, these circles are fully relaxed. In vivo, EB causes helix distortion of free minicircles, preventing replication initiation and resulting in kDNA loss and cell death. Unexpectedly, EB also kills dyskinetoplastic trypanosomes, lacking kDNA, by inhibiting nuclear replication. Since the effect on kDNA occurs at a >10-fold lower EB concentration than that on nuclear DNA, we conclude that minicircle replication initiation is likely EB's most vulnerable target, but the effect on nuclear replication may also contribute to cell killing.

  3. Proceedings of workshop on 'boron chemistry and boron neutron capture therapy'

    International Nuclear Information System (INIS)

    This volume contains the proceedings of the 4th Workshop on 'the Boron Chemistry and Boron Neutron Capture Therapy' held on February 24 in 1992. First, clinical experiences of BNCT in the Kyoto University Research Reactor in 1992 were briefly reported. Then, the killing effects of boron cluster-containing nucleic acid precursors on tumor cells were shown (Chap. 2). The various trials of the optical resolution of B-p-boronophenylalanine for neutron capture therapy were made (Chap. 3). The borate-dextran gel complexes were investigated by the nuclear magnetic resonance spectroscopy. The stability constants of borate complexes were listed, and are useful in the solution chemistry of boron compounds (Chap. 4). The interactions between boron compounds and biological materials were studied by the paper electrophoresis which had been developed by us (Chap. 5). Molecular design of boron-10 carriers and their organic synthesis were reported (Chap. 6). Carborane-containing aziridine boron carriers which were directed to the DNA alkylation were synthesized and their cancer cell killing efficacies were tested (Chap. 7). The solution chemistry of deuterium oxide which is a good neutron moderator was reported, relating to the BNCT (Chap. 8). (author)

  4. Synthesis of multiwall boron nitride nanotubes dependent on crystallographic structure of boron

    International Nuclear Information System (INIS)

    Synthesis and growth of multiwall boron nitride nanotubes (BNNTs) under the B and ZrO2 seed system in the milling–annealing process were investigated. BNNTs were synthesized by annealing a mechanically activated boron powder under nitrogen environment. We explored the aspects of the mechanical activation energy transferred to milled crystalline boron powder producing structural disorder and borothermal reaction of the ZrO2 seed particles on the synthesis of BNNTs during annealing. Under these circumstances, the chemical reaction of amorphous boron coated on the seed nanoparticles with nitrogen synthesizing amorphous BN could be enhanced. It was found that amorphous BN was crystallized to the layer structure and then grown to multiwall BNNTs during annealing. Especially, bamboo-type multiwall BNNTs were mostly produced and grown to the tail-side of the nanotube not to the round head-side. Open gaps with ∼0.3 nm of the bamboo side walls of BNNTs were also observed. Based on these understandings, it might be possible to produce bamboo-type multiwall BNNTs by optimization of the structure and shape of boron coat on the seed nanoparticles. -- Highlights: ► Structure of B is a key factor for BNNT synthesis for milling–annealing method. ► Amorphous boron is coated on the seed during milling of crystalline boron. ► Amorphous BN nanoclusters are crystallized during annealing. ► Growing of bamboo BNNTs is not to the round head-side but to the tail-side.

  5. INFLUENCE OF FINE-DISPERSED BORON CARBIDE ON THE STRUCTURE AND CHARACTERISTICS OF IRON-BORON ALLOY

    Directory of Open Access Journals (Sweden)

    N. F. Nevar

    2016-02-01

    Full Text Available The influence of boron carbide as fine-dispersed material input into the melt on structure morphology, founding, technological and exploitation characterisstics of cast iron-boron material is shown.

  6. Colorimetric Sugar Sensing Using Boronic Acid-Substituted Azobenzenes

    Directory of Open Access Journals (Sweden)

    Yuya Egawa

    2014-02-01

    Full Text Available In association with increasing diabetes prevalence, it is desirable to develop new glucose sensing systems with low cost, ease of use, high stability and good portability. Boronic acid is one of the potential candidates for a future alternative to enzyme-based glucose sensors. Boronic acid derivatives have been widely used for the sugar recognition motif, because boronic acids bind adjacent diols to form cyclic boronate esters. In order to develop colorimetric sugar sensors, boronic acid-conjugated azobenzenes have been synthesized. There are several types of boronic acid azobenzenes, and their characteristics tend to rely on the substitute position of the boronic acid moiety. For example, o-substitution of boronic acid to the azo group gives the advantage of a significant color change upon sugar addition. Nitrogen-15 Nuclear Magnetic Resonance (NMR studies clearly show a signaling mechanism based on the formation and cleavage of the B–N dative bond between boronic acid and azo moieties in the dye. Some boronic acid-substituted azobenzenes were attached to a polymer or utilized for supramolecular chemistry to produce glucose-selective binding, in which two boronic acid moieties cooperatively bind one glucose molecule. In addition, boronic acid-substituted azobenzenes have been applied not only for glucose monitoring, but also for the sensing of glycated hemoglobin and dopamine.

  7. Boron-containing amino carboxylic acid compounds and uses thereof

    International Nuclear Information System (INIS)

    Novel compounds which are useful for boron neutron capture therapy (BNCT) are disclosed. The compounds comprise a stable boron-containing group and an aminocycloalkane carboxylic acid group or a boronated acyclic hydrocarbon-linked amino carboxylic acid. Methods for synthesis of the compounds and for use of the compounds in BNCT are disclosed

  8. Enhanced Plasma Performance by ICRF Boronization

    Institute of Scientific and Technical Information of China (English)

    万宝年; 赵燕平; 李建刚; 宋梅; 吴振伟; 罗家融; 李成富; 王小明

    2002-01-01

    Boronization with carborane (C2B10H12) by ICRF has been applied routinely to the walls of HT-7 super-conducting tokamak for the reduction of impurity influx, especially carbon and oxygen. Significant suppression of metallic impurities and radiating power fraction are achieved. The improved confinement for both particle and energy is observed in full range of operation parameters. Energy balance analysis shows that electron heat diffusion coefficient is strongly reduced. Measurements by Langmuir probes at the edge plasma show that the poloidal velocity shear after boronization is changed to a profile favoring to good confinement. The main emphasis of this paper is to describe effects of boronization on aspects of the enhanced plasma performance.

  9. Anomalous electronic transport in boron carbides

    Science.gov (United States)

    Emin, D.; Samara, G. A.; Wood, C.

    The boron carbides are composed of icosahedral units, B12 and B11C1, linked together by strong intericosahedral bonds. With such distributions of icosahedral and intericosahedral compositions, boron carbides, B/sub 1-x/C/sub x/, are single phase over 0.1 less than or equal to x less than or equal to 0.2. The electronic transport properties of the boron carbides were examined within this single-phase region. Results are inconsistent with conventional analyses of both itinerant and hopping transport. Most striking are Seebeck coefficients which are both large and rapidly increasing functions of temperature despite thermally activated dc conductivities. These results manifest the hopping of small bipolaronic holes between carbon-containing icosahedral that are inequivalent in energy and electron-lattice coupling strength. Under hydrostatic pressures up to approx. 25 kbar, the dc conductivities increase with pressure. This anomalous behavior for hopping conduction reflects the distinctive structure and bonding of these materials.

  10. Single step synthesis of nanostructured boron nitride for boron neutron capture therapy

    International Nuclear Information System (INIS)

    Nanostructured Boron Nitride (BN) has been successfully synthesized by carbo-thermic reduction of Boric Acid (H3BO3). This method is a relatively low temperature synthesis route and it can be used for large scale production of nanostructured BN. The synthesized nanoparticles have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and differential thermal analyzer (DTA). XRD analysis confirmed the formation of single phase nanostructured Boron Nitride. SEM analysis showed that the particles are spherical in shape. DTA analysis showed that the phase is stable upto 900 °C and the material can be used for high temperature applications as well boron neutron capture therapy (BNCT)

  11. Single step synthesis of nanostructured boron nitride for boron neutron capture therapy

    Science.gov (United States)

    Singh, Bikramjeet; Singh, Paviter; Kumar, Manjeet; Thakur, Anup; Kumar, Akshay

    2015-05-01

    Nanostructured Boron Nitride (BN) has been successfully synthesized by carbo-thermic reduction of Boric Acid (H3BO3). This method is a relatively low temperature synthesis route and it can be used for large scale production of nanostructured BN. The synthesized nanoparticles have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and differential thermal analyzer (DTA). XRD analysis confirmed the formation of single phase nanostructured Boron Nitride. SEM analysis showed that the particles are spherical in shape. DTA analysis showed that the phase is stable upto 900 °C and the material can be used for high temperature applications as well boron neutron capture therapy (BNCT).

  12. boron and boron nitride coated nuclear fuel production in plasma atmosphere

    International Nuclear Information System (INIS)

    In these study uranium dioxide (UO2) and 5, 10 % gadolinium oxide (Gd2O3) containing UO2 nuclear fuel pellets were coated with first boron nitride (BN) then boron (B) layers as the results of the reactions between boron trichloride (BCl3) with ammonia (NH3) and BCl3 with hydrogen (H2) in the medium of argon (Ar) plasma created at 650 W and 500 W and 27.12 MHz to increase the fuel burnup efficiency and reactor core life by the method of plasma enhanced chemical vapor deposition (PECVD). Grainy BN and B structures were observed on the photographs taken from scanning electron microscope (SEM)

  13. A system to deposit boron films (boronization) in the DIII-D tokamak

    International Nuclear Information System (INIS)

    A system has been added to the D3-D tokamak to coat its plasma facing surfaces with a film of boron using diborane gas. The system includes special health and safety equipment for handling the diborane gas which is toxic and inflammable. The purpose of the boron film is to reduce the levels of impurity atoms in the D3-D plasmas. Experiments following the application of the boron film in D3-D have led to significant reductions in plasma impurity levels and the observation of a new, very high confinement regime. 9 refs., 1 fig

  14. Boron Nitride Nanotubes for Spintronics

    Directory of Open Access Journals (Sweden)

    Kamal B. Dhungana

    2014-09-01

    Full Text Available With the end of Moore’s law in sight, researchers are in search of an alternative approach to manipulate information. Spintronics or spin-based electronics, which uses the spin state of electrons to store, process and communicate information, offers exciting opportunities to sustain the current growth in the information industry. For example, the discovery of the giant magneto resistance (GMR effect, which provides the foundation behind modern high density data storage devices, is an important success story of spintronics; GMR-based sensors have wide applications, ranging from automotive industry to biology. In recent years, with the tremendous progress in nanotechnology, spintronics has crossed the boundary of conventional, all metallic, solid state multi-layered structures to reach a new frontier, where nanostructures provide a pathway for the spin-carriers. Different materials such as organic and inorganic nanostructures are explored for possible applications in spintronics. In this short review, we focus on the boron nitride nanotube (BNNT, which has recently been explored for possible applications in spintronics. Unlike many organic materials, BNNTs offer higher thermal stability and higher resistance to oxidation. It has been reported that the metal-free fluorinated BNNT exhibits long range ferromagnetic spin ordering, which is stable at a temperature much higher than room temperature. Due to their large band gap, BNNTs are also explored as a tunnel magneto resistance device. In addition, the F-BNNT has recently been predicted as an ideal spin-filter. The purpose of this review is to highlight these recent progresses so that a concerted effort by both experimentalists and theorists can be carried out in the future to realize the true potential of BNNT-based spintronics.

  15. Reactive sputter deposition of boron nitride

    International Nuclear Information System (INIS)

    The preparation of fully dense, boron targets for use in planar magnetron sources has lead to the synthesis of Boron Nitride (BN) films by reactive rf sputtering. The deposition parameters of gas pressure, flow and composition are varied along with substrate temperature and applied bias. The films are characterized for composition using Auger electron spectroscopy, for chemical bonding using Raman spectroscopy and for crystalline structure using transmission electron microscopy. The deposition conditions are established which lead to the growth of crystalline BN phases. In particular, the growth of an adherent cubic BN coating requires 400--500 C substrate heating and an applied -300 V dc bias

  16. Can Two-Dimensional Boron Superconduct?

    Science.gov (United States)

    Penev, Evgeni S; Kutana, Alex; Yakobson, Boris I

    2016-04-13

    Two-dimensional boron is expected to exhibit various structural polymorphs, all being metallic. Additionally, its small atomic mass suggests strong electron-phonon coupling, which in turn can enable superconducting behavior. Here we perform first-principles analysis of electronic structure, phonon spectra, and electron-phonon coupling of selected 2D boron polymorphs and show that the most stable structures predicted to feasibly form on a metal substrate should also exhibit intrinsic phonon-mediated superconductivity, with estimated critical temperature in the range of Tc ≈ 10-20 K. PMID:27003635

  17. Thermal conductivity behavior of boron carbides

    Science.gov (United States)

    Wood, C.; Zoltan, A.; Emin, D.; Gray, P. E.

    1983-01-01

    Knowledge of the thermal conductivity of boron carbides is necessary to evaluate its potential for high temperature thermoelectric energy conversion applications. The thermal diffusivity of hot pressed boron carbide B/sub 1-x/C/sub x/ samples as a function of composition, temperature and temperature cycling was measured. These data in concert with density and specific heat data yield the thermal conductivities of these materials. The results in terms of a structural model to explain the electrical transport data and novel mechanisms for thermal conduction are discussed.

  18. Aclidinium bromide combined with formoterol inhibits remodeling parameters in lung epithelial cells through cAMP.

    Science.gov (United States)

    Lambers, Christopher; Costa, Luigi; Ying, Qi; Zhong, Jun; Lardinois, Didier; Dekan, Gerhard; Schuller, Elisabeth; Roth, Michael

    2015-12-01

    Combined muscarinic receptor antagonists and long acting β2-agonists improve symptom control in chronic obstructive pulmonary disease (COPD) significantly. In clinical studies aclidinium bromide achieved better beneficial effects than other bronchodilators; however, the underlying molecular mechanisms are unknown. This study assessed the effect of aclidinium bromide combined with formoterol on COPD lung (n=20) and non-COPD lung (n=10) derived epithelial cells stimulated with TGF-β1+carbachol on: (i) the generation of mesenchymal cells in relation to epithelial cells, (II) extracellular matrix (ECM) deposition, and (iii) the interaction of ECM on the generation of epithelial and mesenchymal cells. TGF-β1+carbachol enhanced the generation of mesenchymal cells, which was significantly reduced by aclidinium bromide or formoterol. The effect of combined drugs was additive. Inhibition of p38 MAP kinase and Smad by specific inhibitors or aclidinium bromide reduced the generation of mesenchymal cells. In mesenchymal cells, TGF-β1+carbachol induced the deposition of collagen-I and fibronectin which was prevented by both drugs dose-dependently. Formoterol alone reduced collagen-I deposition via cAMP, this however, was overruled by TGF-β1+carbachol and rescued by aclidinium bromide. Inhibition of fibronectin was cAMP independent, but involved p38 MAP kinase and Smad. Seeding epithelial cells on ECM collagen-I and fibronectin induced mesenchymal cell generation, which was reduced by aclidinium bromide and formoterol. Our results suggest that the beneficial effect of aclidinium bromide and formoterol involves cAMP affecting both, the accumulation of mesenchymal cells and ECM remodeling, which may explain the beneficial effect of the drugs on lung function in COPD. PMID:26546746

  19. Characterization of soluble bromide measurements and a case study of BrO observations during ARCTAS

    Directory of Open Access Journals (Sweden)

    J. Liao

    2011-09-01

    Full Text Available A focus of the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS mission was examination of bromine photochemistry in the spring time, high latitude troposphere based on aircraft and satellite measurements of BrO and related species. The NASA DC-8 aircraft utilized a chemical ionization mass spectrometry (CIMS instrument to measure BrO and a mist chamber (MC to measure soluble bromide. We have determined that the MC detection efficiency to molecular bromine (Br2, hypobromous acid (HOBr, bromine oxide (BrO, and hydrogen bromide (HBr as soluble bromide (Br was 0.9±0.1, 1.06±0.30, 0.4±0.1, and 0.95±0.1, respectively. These efficiency factors were used to estimate soluble bromide levels along the DC-8 flight track of 17 April 2008 from photochemical calculations constrained to in situ BrO measured by CIMS. During this flight, the highest levels of soluble bromide and BrO were observed and atmospheric conditions were ideal for the space-borne observation of BrO. The good agreement (R2 = 0.76; slope = 0.98; intercept = −3.5 pptv between modeled and observed soluble bromide, when BrO was above detection limit (>2 pptv under unpolluted conditions (NO < 100 pptv, indicates that the CIMS BrO measurements were consistent with the MC soluble bromide. Tropospheric BrO vertical column densities (BROTROPVCD derived from CIMS BrO observations compare well with BROTROPVCD from OMI on 17 April 2008.

  20. Boron carbide-based ceramics via polymer route synthesis

    International Nuclear Information System (INIS)

    Boron carbide is a ceramic material with excellent high temperature physical properties. As compared to conventional techniques, the preparation of boron carbide from polymeric precursors is attractive as this technique offers a number of unique advantages. In this paper, the screening of polymeric precursors to boron carbide will be discussed. Two promising boron carbide, carborane containing polymeric precursors have resulted in 60-70 wt.% ceramic yields. The chemistry of polymer synthesis and the transformations from the polymer to amorphous and crystalline boron carbide were investigated with infrared spectroscopy, NMR spectroscopy, thermal analysis, and x-ray diffraction

  1. Determination of carbon and sulphur in boron carbide

    International Nuclear Information System (INIS)

    Boron carbide is used in control rods of nuclear power reactors. The chemical specification for carbon in boron carbide ranges between 15 - 24 wt.% depending upon the grade of boron carbide. Hence carbon in boron carbide is to be determined accurately to find out the stoichiometry. Sulphur, which is present in trace quantities, is also to be determined to find out the purity of boron carbide. Carbon is determined by combustion followed by (i) thermal conductivity detection and (ii) infrared detection. Sulphur is determined by (i) combustion followed by infrared detection and (ii) vacuum combustion extraction - quadrupole mass spectrometry. The results are compared. (author)

  2. Direct evidence of metallic bands in a monolayer boron sheet

    Science.gov (United States)

    Feng, Baojie; Zhang, Jin; Liu, Ro-Ya; Iimori, Takushi; Lian, Chao; Li, Hui; Chen, Lan; Wu, Kehui; Meng, Sheng; Komori, Fumio; Matsuda, Iwao

    2016-07-01

    The search for metallic boron allotropes has attracted great attention in the past decades and recent theoretical works predict the existence of metallicity in monolayer boron. Here, we synthesize the β12-sheet monolayer boron on a Ag(111) surface and confirm the presence of metallic boron-derived bands using angle-resolved photoemission spectroscopy. The Fermi surface is composed of one electron pocket at the S ¯ point and a pair of hole pockets near the X ¯ point, which is supported by the first-principles calculations. The metallic boron allotrope in β12 sheet opens the way to novel physics and chemistry in material science.

  3. Medical chemistry of boron neutron capture agents having pharmacological activity

    International Nuclear Information System (INIS)

    Boron neutron capture therapy (BNCT) is a cancer treatment that selectively destroys cancer cells following administering a cancer-selective drug containing stable isotope boron-10 and neutron irradiation. In clinical trial of BNCT, disodium mercaptoundecahydro-closo-dodecaborate (BSH) and p-boronophenylalanine (BPA) have been used, however, development of a new drugs with high cancer selectivity and therapeutic efficiency is expected. Therefore, we review boron-containing drugs as a boron neutron capture agents having pharmacological activity, BNCT research on boron-modified porphyrin derivatives which have photosensitivity and neutron capture activity and our proposed neutron sensitizing agent. (author)

  4. Inefficiency of high boron concentrations for cell killing in boron neutron capture therapy

    International Nuclear Information System (INIS)

    This study is to investigate the relationship between the cell-killing effect of the 10B(n, α)7Li capture reaction, intracellular boron concentration, and thermal neutron fluence in boron neutron capture therapy using in vitro cell survival based on a clonogenic assay, and biophysical analysis. Our results showed that the cell-killing yield of the 10B(n, α)7Li capture reaction per unit thermal neutron fluence declined with an increase in the intracellular boron concentration above 45 μg/ml 10B. The cell-killing effect was well described using an empirical power function of the intracellular boron concentration, with exponent 0.443. Knowledge of this effect will help in the optimization of BNCT. (author)

  5. Effect of metal hydrides on the burning characteristics of boron

    International Nuclear Information System (INIS)

    Highlights: • The effect of some metal hydrides on the burning characteristics of boron is studied for the first time. • We are the first to conduct a TG experiment on boron samples at high temperatures (a maximum of 1750 °C). • The thermal reaction process of boron is firstly divided into five stages according to the weight gain rate of the sample. • Specific values of metal hydrides on ignition delay time and combustion intensity of boron are obtained. - Abstract: In this study, the effect of four metal hydrides on the burning characteristics of boron was investigated. Thermogravimetric experiment results show that the thermal reaction process of boron samples can be divided into five stages. The thermal reactions of boron can be significantly promoted with LiH, which can reduce the initial temperature of the first violent reaction stage by ∼140 °C. The starting temperature of the post-reaction stage also decreases by ∼260 °C. The results of the laser ignition experiment suggest that all four metal hydrides can promote boron burning. Nonetheless, different metal hydrides display varied promotional effects. Among the studied hydrides, LiH is the most effective additive and shortens the ignition delay time of boron by ∼34.1%. Moreover, it enhances the combustion intensity of boron by ∼117.6%. The other three metal hydrides (CaH2, TiH2, and ZrH2) can also contribute to boron burning

  6. Removal properties of dissolved boron by glucomannan gel.

    Science.gov (United States)

    Oishi, Kyoko; Maehata, Yugo

    2013-04-01

    Boron ions have long been known to form complexes with the cis-diol group of a polysaccharide. Konjac glucomannan (KGM) which is one of polysaccharides was used to remove dissolved boron in this study. KGM forms a complex with boron, but does not remove boron from contaminated waters as well as other polysaccharides because of its high water solubility. Therefore, the removal efficiencies of dissolved boron were examined using both an insoluble KGM gel and KGM semi-gel. The former did not remove dissolved boron, but the latter did. The difference in the ability of boron removal was due to the presence of diol group inside. KGM loses free diol group during the process of gelation. On the other hand, the semi-gel gelated only surface layer in water has diol group inside. The boron removal capacity of the semi-gel was highest at pHs⩾11, when the boron species is present as B(OH)4(-). The capacity was slightly increased by the addition of Al, Ca and Mg under high pH conditions. This was due to co-precipitation of boron with Ca dissolved from the semi-gel. The boron adsorbed to the semi-gel easily was desorbed under low pH conditions and the hysteresis was not found. PMID:23260255

  7. Relationship Between Soil Boron Adsorption Kinetics and Rape Plant Boron Response

    Institute of Scientific and Technical Information of China (English)

    ZHUDUANWEI; PIMEIMEI; 等

    1997-01-01

    The boron adsorption kinetic experiment in soil by means a flow displacement technique showed that the kinetic data could be described with some mathematic equations.The average values of the coorealtion coefficeint for zero-order,first-order,parabolic diffusion ,Elovich,power function and eponential equations were 0.957,0.982,0.981,0.984,0.981 and 0.902 ,respectively,The correlation between adsorbed boron or its other expression form and time were the highest for first-order ,parabloic diffusion Elovich,and pwer function equations,the second for the zeroorder equation,and the tlowest for the exponential equation.The parabloic diffusion equation fitted well the expermiental results,with the least standard error among the six kinetic equation,showing that the monvemetn of boron from soil solution to soil colloid surface may be controlled by boron diffusion speed.The boron content of rape seedling obtained from soil cultvation was correlated with the rate constants of the kinetic equations.The constants of first-order ,parabloic diffusion,and exponential equaitions were significanlty correlated with the boron content of the crop of NPK treatment at a 95% probaility level ,with correation coeffecients being 0.686,0.691 and 0.64 and 0.641,respectively.In the case of zero-order equation,it Was significant at 99% probability level(r=0.736),These results showed that the adsorption kinetic constants of soil boron were closely related with the rape plant response to boron.

  8. The structure and local chemical properties of boron-terminated tetravacancies in hexagonal boron-nitride

    OpenAIRE

    Cretu, Ovidiu; Lin, Yung-Chang; Koshino, Masanori; Tizei, Luiz H. G.; Liu, Zheng; Suenaga, Kazutomo

    2014-01-01

    Imaging and spectroscopy performed in a low-voltage scanning transmission electron microscope (LV-STEM) are used to characterize the structure and chemical properties of boron-terminated tetravacancies in hexagonal boron nitride (h-BN). We confirm earlier theoretical predictions about the structure of these defects and identify new features in the electron energy-loss spectra (EELS) of B atoms using high resolution chemical maps, highlighting differences between these areas and pristine sampl...

  9. A colorimetric determination of boron in biological sample for boron neutron capture therapy (BNCT)

    International Nuclear Information System (INIS)

    The boron neutron capture therapy (BNCT) has shown better prognosis in the treatment of glyemas and gluoblastomas grade III and IV than other therapies. During the treatment the levels of Na210B12H11SH must be known in several compartiments of the organism and with this purpose the method of colorimetric determination of boron using curcumine was established. This method is simple, reprodutible and adequate sensitivity for this control. (author)

  10. Effects of boron number per unit volume on the shielding properties of composites made with boron ores form China

    International Nuclear Information System (INIS)

    The total macroscopic removal cross sections, deposited energies and the absorbed doses of three new shielding composites loaded with specific boron-rich slag, boron concentrate ore and boron mud of China for 252Cf neutron source were investigated by experimental and Monte Carlo calculation. The results were evaluated by boron mole numbers per unit volume in composites. The half value layers of the composites were calculated and compared with that of Portland concrete, indicating that ascending boron mole numbers per unit volume in the composites can enhance the shielding properties of the composites for 252Cf neutron source. (authors)

  11. Reversed phase-high performance liquid chromatographic method to measure migration of semivolatile compound, vanillin, in ipratropium bromide inhalation solution

    OpenAIRE

    Conkins, Dennis; Economou, Julia E; Boersma, James A; Dedhiya, Mehendra G; Hansen, Gordon

    1999-01-01

    Ipratropium bromide, a bronchodilator, is used as an inhalation solution. Commercial ipratropium bromide solution products are packaged in low-density polyethylene (LDPE) vials, through which semivolatile compounds are reported to migrate. In this article, a specific reversed phase-high performance liquid chromatographic method to assay vanillin, a semivolatile compound, in ipratropium bromide solution is described. The method was validated for a concentration range for vanillin from 30 ng/mL...

  12. Synthesis and evaluation of boron folates for Boron-Neutron-Capture-Therapy (BNCT)

    Energy Technology Data Exchange (ETDEWEB)

    Kettenbach, Kathrin; Schieferstein, Hanno; Grunewald, Catrin; Hampel, Gabriele; Schuetz, Christian L. [Mainz Univ. (Germany). Inst. of Nuclear Chemistry; Iffland, Dorothee; Bings, Nicolas H. [Mainz Univ. (Germany). Inst. of Inorganic Chemistry and Analytical Chemistry; Reffert, Laura M. [Hannover Medical School (Germany). Radiopharmaceutical Chemistry; Ross, Tobias L. [Mainz Univ. (Germany). Inst. of Nuclear Chemistry; Hannover Medical School (Germany). Radiopharmaceutical Chemistry

    2015-07-01

    Boron neutron capture therapy (BNCT) employs {sup 10}B-pharmaceuticals administered for the treatment of malignancies, and subsequently irradiated with thermal neutrons. So far, clinical established pharmaceuticals like boron phenylalanine (BPA) or sodium boron mercaptate (BSH) use imperfect (BPA) or passive (BSH) targeting for accumulation at target sites. Due to the need of a selective transportation of boron drugs into cancer cells and sparing healthy tissues, we combined the BNCT approach with the specific and effective folate receptor (FR) targeting concept. The FR is overexpressed on many human carcinomas and provides a selective and specific target for molecular imaging as well as for tumor therapy. We synthesized and characterized a carborane-folate as well as a BSH-folate to study their in vitro characteristics and their potential as new boron-carriers for BNCT. Uptake studies were carried out using human KB cells showing a significant increase of the boron content in cells and demonstrating the successful combination of active FR-targeting and BNCT.

  13. Rapid mass-spectrometric determination of boron isotopic distribution in boron carbide.

    Science.gov (United States)

    Rein, J E; Abernathey, R M

    1972-07-01

    Boron isotopic ratios are measured in boron carbide by thermionic ionization mass spectrometry with no prior chemical separation. A powder blend of boron carbide and sodium hydroxide is prepared, a small portion is transferred to a tantalum filament, the filament is heated to produce sodium borate, and the filament is transferred to the mass spectrometer where the(11)B/(10)B ratio is measured, using the Na(2)BO(2)(+) ion. Variables investigated for their effect on preferential volatilization of (10)B include the sodium hydroxide-boron carbide ratio and the temperature and duration of filament heating. A series of boron carbide pellets containing natural boron, of the type proposed for the control rods of the Fast Flux Test Facility reactor, were analysed with an apparently unbiased result of 4.0560 for the (11)B/(10)B ratio (standard deviation 0.0087). The pellets contained over 3% metal impurities typically found in this material. Time of analysis is 45 min per sample, with one analyst. PMID:18961131

  14. Coadsorption of lanthanum with boron and gadolinium with boron on Mo(1 1 0)

    Science.gov (United States)

    Magkoev, Tamerlan T.; Vladimirov, Georgij G.; Rump, Gennadij A.

    2008-05-01

    Submonolayer to multilayer coadsorption of lanthanum (La) with boron (B) and gadolinium (Gd) with boron on the surface of Mo(1 1 0) has been studied by means of Auger electron spectroscopy (AES), electron energy loss spectroscopy (EELS) and work function ( ϕ) measurements. The equilibrium state of double adsorbate systems achieved either by adsorption of rare-earth metal (REM) on boron precovered Mo(1 1 0) surface held at room temperature or after moderate annealing of the system with opposite order of adsorption (B on REM films) is the layer which is the inhomogeneous mixture of boron and REM atoms with preferential concentration of boron in the surface area of the mixed film. The work function of such films even at REM to boron concentration ratio much higher than 1/6 are very close to the values of corresponding bulk LaB 6 and GdB 6, favoring assumption of surface rearrangement as the dominant reason of high electron emission efficiency of hexaborides. Almost total similarity of the results for La-B and Gd-B systems can be viewed as the consequence of weak participation of Gd f-electrons in determining the thermionic properties of corresponding double layers.

  15. Multi-dimensional boron transport modeling in subchannel approach: Part II. Validation of CTF boron tracking model and adding boron precipitation model

    International Nuclear Information System (INIS)

    Highlights: • Validation of implemented multi-dimensional subchannel boron transport model. • Extension of boron transport model to entrained droplets. • Implementation of boron precipitation model. • Testing of the boron precipitation model under transient condition. - Abstract: The risk of small-break loss of coolant accident (SB-LOCA) and other reactivity initiated transients caused by boron dilution in the light water reactors (LWRs), and the complications of tracking the soluble boron concentration experimentally inside the primary coolant have stimulated the interest in computational studies for accurate boron tracking simulations in nuclear reactors. In Part I of this study, the development and implementation of a multi-dimensional boron transport model with modified Godunov scheme based on a subchannel approach within the COBRA-TF (CTF) thermal-hydraulic code was presented. The modified Godunov scheme approach with a physical diffusion term was determined to provide the most accurate and precise solution. Current paper extends these conclusions and presents the model validation studies against experimental data from the Rossendorf coolant mixing model (ROCOM) test facility. In addition, the importance of the two-phase flow characteristics in modeling boron transient are emphasized, especially during long-term cooling period after the loss of coolant accident (LOCA) condition in pressurized water reactors (PWRs). The CTF capabilities of boron transport modeling are further improved based on the three-field representation of the two-phase flow utilized in the code. The boron transport within entrained droplets is modeled, and a model for predicting the boron precipitation under transient conditions is developed and tested. It is aimed to extend the applicability of CTF to reactor transient simulations, and particularly to a large-break loss of coolant accident (LB-LOCA) analysis

  16. PWR core response to boron dilution transient

    International Nuclear Information System (INIS)

    This paper illustrates the steps followed in order to set up a tool (composed of a plant model and of a procedure) that allows accounting for boron reactivity feedbacks during plant transients. The procedure that has been developed allows to find out the values of the boron feedback coefficients, given the differential boron worth, and to properly initialize the Thermal Hydraulic and the Neutronic (TH/NEU) system. Once the tool has been developed, it has been used to analyze different scenarios, resulting from deborated water injection from the reactor make-up system. The most important parameter, during this Reactivity Insertion Accidents (RIAs), is the Energy Released to the Fuel (ERF) and it has been monitored, in order to identify the situations when the fuel might be damaged (ERF > 250 kJ/kg, for high burnup fuel). The analyses have been performed using the RELAP5-3D computer code. The conclusion of the study is that the limited capability of modeling mixing phenomena provided by most common plant codes (such as RELAP5-3D) is not suitable to perform BE analyses of RIAs, since those accidents are so sensitive to boron concentration changes that the effect of uncertainties cannot be neglected. The use of Computational Fluid Dynamics (CFD) codes could reduce uncertainties enough to perform BE analyses and thus it should be recommended. (author)

  17. Pechmann Reaction Promoted by Boron Trifluoride Dihydrate

    Directory of Open Access Journals (Sweden)

    J. Mezger

    2005-08-01

    Full Text Available The Pechmann reaction of substituted phenols 1a-e with methyl acetoacetate (2 can be activated by boron trifluoride dihydrate (3 to give the corresponding 4-methyl- coumarin derivatives 4a-e in excellent yield (98-99 %.

  18. New insight into pecan boron nutrition

    Science.gov (United States)

    Alternate bearing by individual pecan [Carya illinoinensis (Wangenh.) K. Koch] trees is problematic for nut producers and processors. There are many unknowns regarding alternate bearing physiology, such as the relationship between boron and fruit set, nutmeat quality, and kernel maladies. Evidence...

  19. Channeling of boron ions into silicon

    International Nuclear Information System (INIS)

    Channeled and random distributions of boron ions implanted over the energy range 50 keV--1.8 MeV into silicon have been measured using the differential capacitance technique. When implantations are performed along the or axis, profiles exhibit a strong orientation dependance. The best channeled profiles shows that more than 70% of the implanted dose is in the channeled peak

  20. Influence of pollution of boron chlorinity ratio

    Digital Repository Service at National Institute of Oceanography (India)

    Narvekar, P.V.; Zingde, M.D.

    Presence of boron in domestic wastewater has resulted in high B/CI ratio at some locations in the coastal water around Bombay. A widest range (0.215-0.281) of B/CI was observed at a location with high influence of wastewater release. The mean B...

  1. Boron carbide morphology changing under purification

    Science.gov (United States)

    Rahmatullin, I. A.; Sivkov, A. A.

    2015-10-01

    Boron carbide synthesized by using coaxial magnetoplasma accelerator with graphite electrodes was purified by two different ways. XRD-investigations showed content changing and respectively powder purification. Moreover TEM-investigations demonstrated morphology changing of product under purification that was discussed in the work.

  2. Boron carbide synthesis at plasma spray process

    Czech Academy of Sciences Publication Activity Database

    Ctibor, Pavel; Brožek, Vlastimil; Hofman, R.

    Bari : Department of Chemistry, University of Bari, 2003 - (d'Agostino, R.; Favia, P.; Fracassi, F.; Palumbo, F.). s. 631 [International Symposium on Plasma Chemistry/16th./. 22.06.2003-27.06.2003, Taormina] Institutional research plan: CEZ:AV0Z2043910 Keywords : boron carbide , plasma spray process Subject RIV: BL - Plasma and Gas Discharge Physics

  3. Joining of boron carbide using nickel interlayer

    International Nuclear Information System (INIS)

    Carbide ceramics such as boron carbide due to their unique properties such as low density, high refractoriness, and high strength to weight ratio have many applications in different industries. This study focuses on direct bonding of boron carbide for high temperature applications using nickel interlayer. The process variables such as bonding time, temperature, and pressure have been investigated. The microstructure of the joint area was studied using electron scanning microscope technique. At all the bonding temperatures ranging from 1150 to 1300degC a reaction layer formed across the ceramic/metal interface. The thickness of the reaction layer increased by increasing temperature. The strength of the bonded samples was measured using shear testing method. The highest strength value obtained was about 100 MPa and belonged to the samples bonded at 1250 for 75 min bonding time. The strength of the joints decreased by increasing the bonding temperature above 1250degC. The results of this study showed that direct bonding technique along with nickel interlayer can be successfully utilized for bonding boron carbide ceramic to itself. This method may be used for bonding boron carbide to metals as well.

  4. Boron nitride nanosheets reinforced glass matrix composites

    Czech Academy of Sciences Publication Activity Database

    Saggar, Richa; Porwal, H.; Tatarko, P.; Dlouhý, Ivo; Reece, M. J.

    2015-01-01

    Roč. 114, SEP (2015), S26-S32. ISSN 1743-6753 R&D Projects: GA MŠk(CZ) 7AMB14SK155 EU Projects: European Commission(XE) 264526 Institutional support: RVO:68081723 Keywords : Boron nitride nanosheets * Borosilicate glass * Mechanical properties Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 1.163, year: 2014

  5. The manufacturing method of boron carbide

    International Nuclear Information System (INIS)

    The new method for manufacturing of boron carbide as powder with controlled purity and surface development has been described. The suspension of boric acid aqueous solution and carbon black in alcohol has been homogenized mechanically. Water and alcohol are then evaporated during mixing. After drying homogenous mixture is heated in temperature range of 1270-1870 C during one hour

  6. Novel Boron Based Multilayer Thermal Neutron Detector

    CERN Document Server

    SCHIEBER, M

    2010-01-01

    The detector contains four or more layers of natural Boron absorbing thermal neutrons. Thickness of a layer is 0.4 - 1.2 mg/cm2. The layers are deposited on one or on both sides of a metal surface used as contacts. Between the absorbing layers there are gas-filled gaps 3 - 6 mm thick. Electric field of 100 - 200 V/cm is applied to the gas-filled gaps. Natural Boron contains almost 20% of 10B isotope. When atoms of 10B capture a thermal neutron, nuclear reaction occurs, as a result of which two heavy particles - alpha particle and ion 7Li - from the thin absorber layer are emitted in opposing sides. One of the two particles penetrates into gas-filled gap between Boron layers and ionizes the gas. An impulse of electric current is created in the gas-filled gap actuated by the applied electric field. The impulse is registered by an electronic circuit. We have made and tested detectors containing from two to sixteen layers of natural Boron with an efficiency of thermal neutron registration from 2.9% to 12.5% accor...

  7. [Bowel obstruction-induced cholinergic crisis with progressive respiratory failure following distigmine bromide treatment].

    Science.gov (United States)

    Kobayashi, Kazuki; Sekiguchi, Hiroshi; Sato, Nobuhiro; Hirose, Yasuo

    2016-03-01

    A 54-year-old female experienced rapid respiratory failure while being transported in an ambulance to our emergency department for evaluation and management of constipation and abdominal pain. The patient was on treatment with distigmine bromide for postoperative urination disorder and magnesium oxide for constipation. Increased salivary secretions, diminished respiratory excursion, type 2 respiratory failure (PaCO2 : 65 mmHg), low serum cholinesterase, and hypermagnesemia were detected. Imaging studies revealed that the patient had bilateral aspiration pneumonia, fecal impaction in the rectum, and a distended colon causing ileus. The patient was mechanically ventilated and was weaned off the ventilator on day 3. Therapeutic drug monitoring after discharge revealed that the serum level of distigmine bromide on admission was markedly elevated (377.8 ng/mL vs. the normal therapeutic level of 5-10 ng/mL). Distigmine bromide induced a cholinergic crisis with a resultant increase in airway secretions and respiratory failure. In this particular case, orally administered distigmine bromide was excessively absorbed because of prolonged intestinal transit time secondary to fecal impaction and sluggish bowel movement; this caused a cholinergic crisis and hypermagnesemia contributing to respiratory failure. Clinicians should be aware that bowel obstruction in a patient treated with distigmine bromide can increase the risk of a cholinergic crisis. PMID:27255021

  8. BCM6: New Generation of Boron Meter

    International Nuclear Information System (INIS)

    Full text of publication follows: Rolls-Royce has developed a new generation of boron meter, based on more than 30 years of experience. The Rolls-Royce BCM6 boron meter provides Nuclear Power Plant (NPP) operators with the boron concentration of the primary circuit. The meter provides continuous and safe measurements with no manual sampling and no human contact. In this paper, technical features, advantages and customer benefits of the use of the new generation of Rolls-Royce BCM6 boron meter will be detailed. Values and associated alarms are provides over different media: 4-20 mA outputs, relays, displays in the main control room and in the chemical lab, and digital links. A special alarm avoids unexpected homogeneous dilution of the primary circuit, which is a critical operational parameter. The Rolls-Royce BCM6 boron meter is fully configurable over a set of parameters allowing adaptation to customer needs. It has a differential capability, thus eliminating neutronic noise and keeping measurements accurate, even in the case of fuel clad rupture. Measurements are accurate, reliable, and have a quick response time. Equipment meets state-of-the-art qualification requests. Designed in 2008, the BCM6 boron meter is the newest equipment of Rolls-Royce boron meters product line. It has been chosen to equip the French EPR NPP and complies with the state-of-the-art of the technology. Rolls-Royce has more than 30 years of experience in Instrumentation and Controls with more than 75 NPP units operating worldwide. All of this experience return has been put in this new generation of equipment to provide the customer with the best operation. About Rolls-Royce Rolls-Royce is a global business providing integrated power systems for use on land, at sea and in the air. The Group has a balanced business portfolio with leading market positions. Rolls-Royce has a broad range of civil nuclear expertise, including work related to licensing and safety reviews, engineering design

  9. Boron carbide nanowires: Synthesis and characterization

    Science.gov (United States)

    Guan, Zhe

    Bulk boron carbide has been widely used in ballistic armored vest and the property characterization has been heavily focused on mechanical properties. Even though boron carbides have also been projected as a promising class of high temperature thermoelectric materials for energy harvesting, the research has been limited in this field. Since the thermal conductivity of bulk boron carbide is still relatively high, there is a great opportunity to take advantage of the nano effect to further reduce it for better thermoelectric performance. This dissertation work aims to explore whether improved thermoelectric performance can be found in boron carbide nanowires compared with their bulk counterparts. This dissertation work consists of four main parts. (1) Synthesis of boron carbide nanowires. Boron carbide nanowires were synthesized by co-pyrolysis of diborane and methane at low temperatures (with 879 °C as the lowest) in a home-built low pressure chemical vapor deposition (LPCVD) system. The CVD-based method is energy efficient and cost effective. The as-synthesized nanowires were characterized by electron microscopy extensively. The transmission electron microscopy (TEM) results show the nanowires are single crystalline with planar defects. Depending on the geometrical relationship between the preferred growth direction of the nanowire and the orientation of the defects, the as-synthesized nanowires could be further divided into two categories: transverse fault (TF) nanowires grow normal to the defect plane, while axial fault (AF) ones grow within the defect plane. (2) Understanding the growth mechanism of as-synthesized boron carbide nanowires. The growth mechanism can be generally considered as the famous vapor-liquid-solid (VLS) mechanism. TF and AF nanowires were found to be guided by Ni-B catalysts of two phases. A TF nanowire is lead by a hexagonal phase catalyst, which was proved to be in a liquid state during reaction. While an AF nanowires is catalyzed by a

  10. Current and Potential Future Bromide Loads from Coal-Fired Power Plants in the Allegheny River Basin and Their Effects on Downstream Concentrations.

    Science.gov (United States)

    Good, Kelly D; VanBriesen, Jeanne M

    2016-09-01

    The presence of bromide in rivers does not affect ecosystems or present a human health risk; however, elevated concentrations of bromide in drinking water sources can lead to difficulty meeting drinking water disinfection byproduct (DBP) regulations. Recent attention has focused on oil and gas wastewater and coal-fired power plant wet flue gas desulfurization (FGD) wastewater bromide discharges. Bromide can be added to coal to enhance mercury removal, and increased use of bromide at some power plants is expected. Evaluation of potential increases in bromide concentrations from bromide addition for mercury control is lacking. The present work utilizes bromide monitoring data in the Allegheny River and a mass-balance approach to elucidate bromide contributions from anthropogenic and natural sources under current and future scenarios. For the Allegheny River, the current bromide is associated approximately 49% with oil- and gas-produced water discharges and 33% with coal-fired power plants operating wet FGD, with 18% derived from natural sources during mean flow conditions in August. Median wet FGD bromide loads could increase 3-fold from 610 to 1900 kg/day if all plants implement bromide addition for mercury control. Median bromide concentrations in the lower Allegheny River in August would rise to 410, 200, and 180 μg/L under low-, mean-, and high-flow conditions, respectively, for the bromide-addition scenario. PMID:27538590

  11. Standard test methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade aluminum oxide and aluminum oxide-boron carbide composite pellets

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1994-01-01

    1.1 These test methods cover procedures for the chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade aluminum oxide and aluminum oxide-boron carbide composite pellets to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Boron by Titrimetry 7 to 13 Separation of Boron for Mass Spectrometry 14 to 19 Isotopic Composition by Mass Spectrometry 20 to 23 Separation of Halides by Pyrohydrolysis 24 to 27 Fluoride by Ion-Selective Electrode 28 to 30 Chloride, Bromide, and Iodide by Amperometric Microtitrimetry 31 to 33 Trace Elements by Emission Spectroscopy 34 to 46 1.3 The values stated in SI units are to be regarded as the standard. 1.4 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. (F...

  12. Bromide and iodide removal from waters under dynamic conditions by Ag-doped aerogels.

    Science.gov (United States)

    Sánchez-Polo, M; Rivera-Utrilla, J; von Gunten, U

    2007-02-01

    The objective of this study was to analyze the efficiency of Ag-doped aerogels in the removal of bromide and iodide from water. To test the applicability of these aerogels in water treatment, adsorption of bromide and iodide was studied under dynamic conditions using waters from Lake Zurich and a mineral water. The results obtained by using these waters showed a high breakthrough volume (V(0.02)=0.4 L) of the columns, while the height of the mass transfer zone (H(MTZ)=6.8 cm) was low, regardless of the anion under study. Bromide- and iodide-saturated columns were regenerated with NH4OH. No change in the column characteristics was observed after two regeneration treatments, regardless of the type of water considered. PMID:17109877

  13. Skin injuries afflicting three oil workers following contact with calcium bromide and/or calcium chloride.

    Science.gov (United States)

    Saeed, W R; Distante, S; Holmes, J D; Kolhe, P S

    1997-01-01

    Calcium bromide brine is a highly concentrated aqueous solution of calcium bromide and calcium chloride. It is used extensively in the oil industry. This solution and its components are recognized as causes of skin injury and information is available from the manufacturers on their safe use and handling. Two patients who were injured following unprotected skin exposure to this solution and one patient who was injured following exposure to calcium chloride powder are reported. All sustained skin injuries characterised by an absence of pain and a delayed clinical appearance of the full extent of the injury. Furthermore healing was complicated by graft loss or was slow. Although organic bromine compounds are recognized as a cause of skin injuries, no previous reports of such injuries to humans secondary to calcium chloride or bromide exposure were found in the medical literature. Our experience with these patients is described. PMID:9568340

  14. Corrosion Behavior of Austenitic and Duplex Stainless Steels in Lithium Bromide

    Directory of Open Access Journals (Sweden)

    Ayo Samuel AFOLABI

    2009-07-01

    Full Text Available The corrosion behavior of austenitic and duplex stainless steels in various concentrations of lithium, bromide solution was investigated by using the conventional weight loss measurement method. The results obtained show that corrosion of these steels occurred due to the aggressive bromide ion in the medium. Duplex stainless steel shows a greater resistance to corrosion than austenitic stainless steel in the medium. This was attributed to equal volume proportion of ferrite and austenite in the structure of duplex stainless steel coupled with higher content of chromium in its composition. Both steels produced electrochemical noise at increased concentrations of lithium bromide due to continuous film breakdown and repair caused by reduction in medium concentration by the alkaline corrosion product while surface passivity observed in duplex stainless steel is attributed to film stability on this steel.

  15. Characterization of cyanogen bromide peptides of hypoxanthine phosphoribosyltransferase by a micromethod

    International Nuclear Information System (INIS)

    Human hypoxanthine phosphoribosyltransferase (HPRT-EC 2.4.2.8), either from erythrocytes labeled in vitro with 125I or from HeLa cells labeled in vivo with [3H]leucine, [3H]lysine, or [3H]arginine, was cleaved with cyanogen bromide. All four labeled enzymes produced cyanogen bromide peptides with molecular weights of 7800, 5600, 4100, 2500, and 1300 which were separated by sodium dodecyl sulfate urea polyacrylamide gel electrophoresis. Experiments with [35S]methionine-labeled HPRT indicated that 88 to 94% of the 35S label was released by the cyanogen bromide reaction. The relative distribution of radioactivity in each of the tritiated peptides indicates that there are 20 leucines, 15 lysines, and 12 arginines per enzyme subunit

  16. Chloride/bromide ratios in leachate derived from farm-animal waste

    International Nuclear Information System (INIS)

    Results have important implications for identifying animal sources of contaminated groundwater. - Ratios of conservative chemicals have been used to identify sources of groundwater contamination. While chloride/bromide ratios have been reported for several common sources of groundwater contamination, little work has been done on leachate derived from farm-animal waste. In this study, chloride/bromide ratios were measured in leachate derived from longhorn-cattle, quarter-horse, and pygme-goat waste at a farm in Abilene, Texas, USA. (Minimum, median, and maximum) chloride/bromide ratios of (66.5, 85.6, and 167), (119, 146, and 156), and (35.4, 57.8, and 165) were observed for cattle, horses, and goats, respectively. These ratios are below typical values for domestic wastewater and within the range commonly observed for oilfield brine. Results of this study have important implications for identifying sources of contaminated groundwater in settings with significant livestock and/or oil production

  17. Irradiation as a disinfestation method - update on methyl bromide phase out, regulatory action and emerging opportunities

    International Nuclear Information System (INIS)

    Methyl bromide (MeBr), is the most widely used agricultural fumigant in the world for the control of pests and plant diseases. It is used to control pests and diseases in food, agricultural and forestry commodities after harvest, before or during storage or transportation and/or at time of import to control quarantine or storage pests. Knowing MeBr will be phased out has spurred a search for alternative treatments and products, and has placed pressure on regulatory authorities to approve alternatives. Some of methyl bromide use could be replaced with irradiation. Methyl bromide is also used for soil and structural fumigation, and although there is some use of irradiation for packaged soil or greenhouse products, in general, these uses can not be replaced by irradiation. Some radiation processing facilities have either seen increased business to disinfest commodities, or have experienced more inquiries for service. There are many other processes and products competing for this market and irradiation will not win its share of the business without an improved regulatory picture, improved marketing to methyl bromide users and improved information to answer questions from commodity sectors. The United Nations Environment Program - Methyl Bromide Technical Options Committee (MBTOC) provides a venue for the publication or information about the use and availability of irradiation as an alternative to methyl bromide. It provides the technical base to the Montreal Protocol contributing to the setting of phase out dates; this committee is actively researching and assessing all alternatives and needs information about irradiation. The author is a member of the MBTOC committee

  18. Higher boron rejection with a new TFC forward osmosis membrane

    KAUST Repository

    Valladares Linares, Rodrigo

    2014-07-17

    Due to the stringent limits for boron in drinking and irrigation water, water treatment facilities have to incur additional treatment to remove boron down to a safe concentration. Forward osmosis (FO) is a membrane technology that may reduce the energy required to remove boron present in seawater. In direct FO desalination hybrid systems, fresh water is recovered from seawater using a recoverable draw solution, FO membranes are expected to show high boron rejection. This study focuses on determining the boron rejection capabilities of a new generation thin-film composite (TFC) FO membrane compared to a first generation cellulose triacetate (CTA) FO membrane. The effects of water permeate flux, membrane structure, draw solute charge, and reverse solute flux on boron rejection were determined. For TFC and CTA FO membranes, experiments showed that when similar operating conditions are applied (e.g. membrane type and draw solute type) boron rejection decreases with increase in permeate flux. Reverse draw solute flux and membrane fouling have no significant impact on boron rejection. Compared to the first generation CTA FO membrane operated at the same conditions, the TFC FO membrane showed a 40% higher boron rejection capability and a 20% higher water flux. This demonstrates the potential for boron removal for new generation TFC FO membranes. © 2014 © 2014 Balaban Desalination Publications. All rights reserved.

  19. Boron removal from aqueous solution by direct contact membrane distillation

    International Nuclear Information System (INIS)

    The removal of boron from aqueous solution by direct contact membrane distillation (DCMD) was studied with self-prepared polyvinylidene fluoride (PVDF) hollow fiber membranes in the present work. The effect of pH, boron concentration, temperature and salt concentration of the feed solution on the boron rejection was investigated. The experimental results indicated that boron rejection was less dependent on the feed pH and salt concentration. DCMD process had high boron removal efficiency (>99.8%) and the permeate boron was below the maximum permissible level even at feed concentration as high as 750 mg/L. Although the permeate flux was enhanced exponentially with the feed temperature increasing, the influence of feed temperature on the boron rejection could be neglected. Finally, the natural groundwater sample containing 12.7 mg/L of boron was treated by DCMD process. The permeate boron kept below 20 μg/L whether the feed was acidified or not, but pre-acidification was helpful to maintain the permeate flux stability. All the experimental results indicated that DCMD could be efficiently used for boron removal from aqueous solution.

  20. ISOBORDAT: An Online Data Base on Boron Isotopes

    International Nuclear Information System (INIS)

    From 1986, boron isotope data in natural substances increased sharply in scientific publications. Analytical difficulties derived from complex geochemical matrices have been faced and interlaboratory calibrations reported in the boron literature. Boron isotopes are nowdays applied to investigate boron origin and migration in natural waters, sources of boron contamination, water-rock interactions and also contribute to water resource management. This is especially important in those areas where boron content exceeds the local regulations for drinking water supply and boron sources need to be identified. ISOBORDAT, an interactive database on boron isotope composition and content in natural waters is presented to the wider community of boron isotope users. The database's structure, scope and applications are reported, along with a discussion on δ11B values obtained in Italian waters. In the database boron data are structured in the following categories: rainwater, rivers, lakes, groundwater and potential contaminants. New categories (medium and high enthalpy fluids from volcanic and geothermal areas) are anticipated. ISOBORDAT aims to be as interactive as possible and will be developed taking into account information and suggestions received. The database is continually undergoing revision to keep pace with continuous data publication. Indications of data that are missing at present are greatly appreciated. (author)

  1. Synthesis and characterization of ammonium phosphate fertilizers with boron

    Directory of Open Access Journals (Sweden)

    ANGELA MAGDA

    2010-07-01

    Full Text Available The concentration of boron, an essential micronutrient for plants, presents a narrow range between deficiency and toxicity. In order to provide the boron requirement for plants, and to avoid toxicity problems, boron compounds are mixed with basic fertilizers. Sodium borate pentahydrate was used as a boron source. Ammonium orthophosphates fertilizers with boron were prepared by neutralizing phosphoric acid with ammonia and addition of variable amounts of sodium tetraborate pentahydrate to the reaction mixture at a NH3:H3PO4 molar ratio of 1.5. The fertilizers obtained with boron contents ranging from 0.05 to 1 % (w/w were fully characterized by chemical analysis, thermal analysis, X-ray diffraction and infrared spectrophotometry. The studies showed that up to 500 °C, regardless of the boron content, no significant changes concerning thermal stability and nutritional properties occurred. Above 500 °C, an increase of thermal stability with an increase of the boron content was observed. X-Ray diffraction of a heat-treated sample containing 5 % (w/w boron indicated the appearance of boron orthophosphate, BPO4, as a new crystalline phase, and the disappearance of the previous structures above 500 °C, which explains the increase in thermal stability.

  2. Structure and single-phase regime of boron carbides

    Science.gov (United States)

    Emin, David

    1988-09-01

    The boron carbides are composed of twelve-atom icosahedral clusters which are linked by direct covalent bonds and through three-atom intericosahedral chains. The boron carbides are known to exist as a single phase with carbon concentrations from about 8 to about 20 at. %. This range of carbon concentrations is made possible by the substitution of boron and carbon atoms for one another within both the icosahedra and intericosahedral chains. The most widely accepted structural model for B4C (the boron carbide with nominally 20% carbon) has B11C icosahedra with C-B-C intericosahedral chains. Here, the free energy of the boron carbides is studied as a function of carbon concentration by considering the effects of replacing carbon atoms within B4C with boron atoms. It is concluded that entropic and energetic considerations both favor the replacement of carbon atoms with boron atoms within the intericosahedral chains, C-B-C-->C-B-B. Once the carbon concentration is so low that the vast majority of the chains are C-B-B chains, near B13C2, subsequent substitutions of carbon atoms with boron atoms occur within the icosahedra, B11C-->B12. Maxima of the free energy occur at the most ordered compositions: B4C,B13C2,B14C. This structural model, determined by studying the free energy, agrees with that previously suggested by analysis of electronic and thermal transport data. These considerations also provide an explanation for the wide single-phase regime found for boron carbides. The significant entropies associated with compositional disorder within the boron carbides, the high temperatures at which boron carbides are formed (>2000 K), and the relatively modest energies associated with replacing carbon atoms with boron atoms enable the material's entropy to be usually important in determining its composition. As a result, boron carbides are able to exist in a wide range of compositions.

  3. Improved light olefin yield from methyl bromide coupling over modified SAPO-34 molecular sieves.

    Science.gov (United States)

    Zhang, Aihua; Sun, Shouli; Komon, Zachary J A; Osterwalder, Neil; Gadewar, Sagar; Stoimenov, Peter; Auerbach, Daniel J; Stucky, Galen D; McFarland, Eric W

    2011-02-21

    As an alternative to the partial oxidation of methane to synthesis gas followed by methanol synthesis and the subsequent generation of olefins, we have studied the production of light olefins (ethylene and propylene) from the reaction of methyl bromide over various modified microporous silico-aluminophosphate molecular-sieve catalysts with an emphasis on SAPO-34. Some comparisons of methyl halides and methanol as reaction intermediates in their conversion to olefins are presented. Increasing the ratio of Si/Al and incorporation of Co into the catalyst framework improved the methyl bromide yield of light olefins over that obtained using standard SAPO-34. PMID:21203621

  4. Kinetics of bromide catalysed oxidation of dextrose by cerium (IV) in aqueous sulphuric acid solution

    International Nuclear Information System (INIS)

    Kinetics of bromide catalysed oxidation of dextrose by CeIV in aqueous sulphuric acid medium show first order dependence each in dextrose and cerium(IV). The reaction rate decreases on increasing the concentration of hydrogen ion. The increase in [HSO4-] or [SO42-] decreases the rate. The bromide ion shows positive catalytic effect on the reaction rate. The value of activation energy has been calculated and a suitable mechanism confirming to the kinetic data is proposed. (author). 3 refs., 3 tabs

  5. COMPARISON OF ROCURONIUM BROMIDE AND SUCCINYLCHOLINE CHLORIDE FOR USE DURING RAPID SEQUENCE INTUBATION IN ADULTS

    Directory of Open Access Journals (Sweden)

    Ch. Penchalaiah

    2015-08-01

    Full Text Available BACKGROUND AND OBJECTIVE : The goal of rapid sequence intubation is to secure the patients airway smoothly and quickly, minimizing the chances of regurgitation and aspiration of gastric contents. Traditionally succinylcholine chloride has been the neuromuscular blocking drug of choi ce for use in rapid sequence intubation because of its rapid onset of action and profound relaxation. Succinylcholine chloride remains unsurpassed in providing ideal intubating conditions. However the use of succinylcholine chloride is associated with many side effects like muscle pain, bradycardia, hyperkalaemia and rise in intragastric and intraocular pressure. Rocuronium bromide is the only drug currently available which has the rapidity of onset of action like succinylcholine chloride. Hence the present study was undertaken to compare rocuronium bromide with succinylcholine chloride for use during rapid sequence intubation in adult patients. METHODOLOGY : The study population consisted of 90 patients aged between 18 - 60 years posted for various elective su rgeries requiring general anaesthesia . S tudy population was randomly divided into 3 groups with 30 patients in each sub group. 1. Group I : Intubated with 1 mg kg - 1 of succinylcholine chloride (n=30 . 2. Grou p II : Intubated with rocuronium bromide 0.6 mg kg - 1 (n=30 . 3. Group III : Intubated with rocuronium bromide 0.9 mg kg - 1 (n=30 . Intubating conditions were assessed at 60 seconds based on the scale adopted by Toni Magorian et al. 1993. The haemodynamic para meters in the present study were compared using p - value obtained from student t - test . RESULTS : It was noted that succinylcholine chloride 1 mg kg - 1 body weight produced excellent intubating conditions in all patients. Rocuronium bromide 0.6 mg kg - 1 body we ight produced excellent intubating conditions in 53.33% of patients but produced good to excellent intubating conditions in 96.67% of patients. Rocuronium bromide 0.9 mg kg - 1

  6. Photochemical reactions involving nitrosylpentacyanoferrate (II) - bromide system using cadmium sulphide as semiconductor

    International Nuclear Information System (INIS)

    Sodium nitroprusside contains cyanide ligands that are not easily replaced chemically. An effort has been made to substitute this ligand by another anionic ligand like bromide. The rate of this photochemical reaction has been observed spectrophotometrically in the presence of cadmium sulphide as a semiconductor. The effect of different parameters like pH, intensity of light, concentration of sodium nitroprusside and bromide ion on the rate of this substitution reaction has been studied. The product was isolated and characterized by different analytical methods. A tentative mechanism for this photochemical substitution has been proposed. (Author)

  7. Cesium Enhances Long-Term Stability of Lead Bromide Perovskite-Based Solar Cells

    OpenAIRE

    Kulbak, Michael; Gupta, Satyajit; Kedem, Nir; Levine, Igal; Bendikov, Tatyana; Hodes, Gary; Cahen, David

    2015-01-01

    Direct comparison between perovskite-structured hybrid organic-inorganic - methyl ammonium lead bromide (MAPbBr3) and all-inorganic cesium lead bromide (CsPbBr3), allows identifying possible fundamental differences in their structural, thermal and electronic characteristics. Both materials possess a similar direct optical band-gap, but CsPbBr3 demonstrates a higher thermal stability than MAPbBr3. In order to compare device properties we fabricated solar cells, with similarly synthesized MAPbB...

  8. Well-Defined Copper(I) Fluoroalkoxide Complexes for Trifluoroethoxylation of Aryl and Heteroaryl Bromides

    KAUST Repository

    Huang, Ronglu

    2015-03-17

    © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Copper(I) fluoroalkoxide complexes bearing dinitrogen ligands were synthesized and the structure and reactivity of the complexes toward trifluoroethoxylation, pentafluoropropoxylation, and tetrafluoropropoxylation of aryl and heteroaryl bromides were investigated. Efficiency drive: A series of copper(I) fluoroalkoxide complexes bearing N,N ligands have been prepared and structurally characterized. These well-defined complexes serve as efficient reagents for the fluoroalkoxylation of aryl and heteroaryl bromides to produce a wide range of trifluoroethyl, pentafluoropropyl, and tetrafluoropropyl (hetero)aryl ethers in good to excellent yields.

  9. Replacing Conventional Carbon Nucleophiles with Electrophiles: Nickel-Catalyzed Reductive Alkylation of Aryl Bromides and Chlorides

    OpenAIRE

    Everson, Daniel A.; Jones, Brittany A.; Weix, Daniel J.

    2012-01-01

    A general method is presented for the synthesis of alkylated arenes by the chemoselective combination of two electrophilic carbons. Under the optimized conditions, a variety of aryl and vinyl bromides are reductively coupled with alkyl bromides in high yields. Under similar conditions, activated aryl chlorides can also be coupled with bromoalkanes. The protocols are highly functional-group tolerant (−OH, −NHTs, −OAc, −OTs, −OTf, −COMe, −NHBoc, −NHCbz, −CN, −SO2Me), and the reactions are assem...

  10. Evaluating 10B-enriched Boric Acid, Bromide, and Heat as Tracers of Recycled Groundwater Flow near MAR Operations

    Science.gov (United States)

    Becker, T.; Clark, J. F.

    2012-12-01

    County, CA, USA) has been in progress since September 6, 2011, following injection of boric acid enriched in boron-10 (10B) and bromide (Br-) tracers. Tracer concentrations are collected at 9 monitoring wells that have pre-experiment estimated travel times between 0.5 to 180 days. Results indicate that 10B-enriched boric acid is an effective deliberate tracer at MAR sites; however, the ion's movement is slightly retarded relative to bromide by the substrate. 10B/Br- travel time ratios range from 1 to 1.4. In addition to the two deliberate geochemical tracers, heat is being evaluated as a possible intrinsic tracer at MAR sites. At the time of the experiment (late summer), reclaimed water was significantly warmer (~20°F) than the native groundwater as it entered the system. Time series are developed from loggers outfitted at each monitoring well, with measurements recorded hourly accurate to one thousandth of a degree. Results are similar to 10B & Br- travel times and validate the potential of heat as an intrinsic tracer.

  11. Potential of using boric acid as a boron drug for boron neutron capture therapy for osteosarcoma

    International Nuclear Information System (INIS)

    Osteosarcoma is a malignant tumor commonly found in human and animals. The ability of boric acid (BA) to accumulate in osteosarcoma due to the mechanism of the bone formation of cancer cells would make boron neutron capture therapy (BNCT) an alternative therapy for osteosarcoma. This study evaluated the feasibility of using BA as the boron drug for BNCT of bone cancer. The cytotoxicity of BA to L929 cells exceeded that of UMR-106 cells. With 25 μg 10B/mL medium of BA treatment, the boron concentration in UMR-106 cells was higher than that in L929 cells. The biodistribution and pharmacokinetics of BA in Sprague–Dawley (SD) rats were studied by administrating 25 mg 10B/kg body weight to SD rats. Blood boron level decreased rapidly within one hour after BA injection. Boron concentration in the long bone was 4–6 time higher than that of blood. Results of this study suggest that BA may be a potential drug for BNCT for osteosarcoma.

  12. Diffusion Boronizing of H11 Hot Work Tool Steel

    Science.gov (United States)

    Jurči, Peter; Hudáková, Mária

    2011-10-01

    The H11 hot work tool steel was boronized at various processing parameters, austenitized, quenched, and tempered to a core hardness of 47-48 HRC. Microstructure, phase constitution, and microhardness of boronized layers were investigated. Effect of boronized region on the bulk properties was determined by the Charpy impact test. Structure of boronized regions is formed by the compound layers and diffusion inter-layer. The compound layers consisted of only (Fe,Cr)2B phase, but in the case of longer processing time, they contained also of the (Fe,Cr)B-phase. The inter-layer contained enhanced portion of carbides, formed due to carbon diffusion from the boride compounds toward the substrate. Microhardness of boronized layers exceeded considerably 2000 HV 0.1. However, boronizing led to a substantial lowering of the Charpy impact toughness of the material.

  13. Boron Rich Solids Sensors, Ultra High Temperature Ceramics, Thermoelectrics, Armor

    CERN Document Server

    Orlovskaya, Nina

    2011-01-01

    The objective of this book is to discuss the current status of research and development of boron-rich solids as sensors, ultra-high temperature ceramics, thermoelectrics, and armor. Novel biological and chemical sensors made of stiff and light-weight boron-rich solids are very exciting and efficient for applications in medical diagnoses, environmental surveillance and the detection of pathogen and biological/chemical terrorism agents. Ultra-high temperature ceramic composites exhibit excellent oxidation and corrosion resistance for hypersonic vehicle applications. Boron-rich solids are also promising candidates for high-temperature thermoelectric conversion. Armor is another very important application of boron-rich solids, since most of them exhibit very high hardness, which makes them perfect candidates with high resistance to ballistic impact. The following topical areas are presented: •boron-rich solids: science and technology; •synthesis and sintering strategies of boron rich solids; •microcantileve...

  14. Boron carbide whisker and platelet reinforced ceramic matrix composites

    International Nuclear Information System (INIS)

    Boron carbide whisker and platelet-reinforced alumina and boron-carbide-whisker-reinforced silicon carbide composites were prepared by hot-pressing. The mechanical properties of hot-pressed boron carbide platelet and whisker-reinforced composites are better than the inherent ceramic matrix. A maximum fracture toughness, K(lc), of 9.5 MPa sq rt m is achieved for alumina/boron carbide whisker composites, 8.6 MPa sq rt m is achieved for alumina/boron carbide platelet composites, and 3.8 MPa sq rt m is achieved for silicon carbide/boron carbide whisker composites. The fracture toughness is dependent on the volume fraction of the platelets and whiskers. 12 refs

  15. Van Hove singularities of some icosahedral boron-rich solids by differential reflectivity spectra

    Science.gov (United States)

    Werheit, Helmut

    2015-09-01

    Differential reflectivity spectra of some icosahedral boron rich solids, β-rhombohedral boron, boron carbide and YB66-type crystals, were measured. The derivatives yield the van Hove singularities, which are compared with results obtained by other experimental methods.

  16. Once-daily glycopyrronium bromide (Seebri Breezhaler(®)) for the treatment of chronic obstructive pulmonary disease (COPD)

    DEFF Research Database (Denmark)

    Ulrik, Charlotte Suppli

    2015-01-01

    also on health status. Furthermore, glycopyrronium bromide also has beneficial effects on dynamic hyperinflation and, probably by that, exercise tolerance. Glycopyrronium bromide has been shown to reduce the rate of exacerbations in patients with moderate to severe COPD, although as a secondary outcome...

  17. Nickel-catalyzed Kumada cross-coupling reactions of tertiary alkylmagnesium halides and aryl bromides/triflates.

    Science.gov (United States)

    Joshi-Pangu, Amruta; Wang, Chao-Yuan; Biscoe, Mark R

    2011-06-01

    We report a Ni-catalyzed process for the cross-coupling of tertiary alkyl nucleophiles and aryl bromides. This process is extremely general for a wide range of electrophiles and generally occurs with a ratio of retention to isomerization >30:1. The same procedure also accommodates the use of aryl triflates, vinyl chlorides, and vinyl bromides as the electrophilic component. PMID:21553878

  18. Multidimensional boron transport modeling in subchannel approach

    International Nuclear Information System (INIS)

    The main objective of this study is to implement a solute tracking model into the subchannel code CTF for simulations of boric acid transients. Previously, three different boron tracking models have been implemented into CTF and based on the applied analytical and nodal sensitivity studies the Modified Godunov Scheme approach with a physical diffusion term has been selected as the most accurate and best estimate solution. This paper will present the implementation of a multidimensional boron transport modeling with Modified Godunov Scheme within a thermal-hydraulic code based on a subchannel approach. Based on the cross flow mechanism in a multiple-subchannel rod bundle geometry, heat transfer and lateral pressure drop effects will be discussed in deboration and boration case studies. (author)

  19. Synthesis and characterization of boron nitrides nanotubes

    International Nuclear Information System (INIS)

    This paper presents a new synthesis for the production of boron nitride nanotubes (BNNT) from boron powder, ammonium nitrate and hematite tube furnace CVD method. The samples were subjected to some characterization techniques as infrared spectroscopy, thermal analysis, X-ray diffraction and scanning electron microscopy and transmission. By analyzing the results can explain the chemical reactions involved in the process and confirm the formation of BNNT with several layers and about 30 nanometers in diameter. Due to excellent mechanical properties and its chemical and thermal stability this material is promising for various applications. However, BNNT has received much less attention than carbon nanotubes, it is because of great difficulty to synthesize appreciable quantities from the techniques currently known, and this is one of the main reasons this work.(author)

  20. Microadditions of boron and vanadium in ADI

    Directory of Open Access Journals (Sweden)

    Rzychoń T.

    2007-01-01

    Full Text Available In the second part of the study, describing the role of vanadium and boron microadditions in the process of structure formation in heavy-walled castings made from ADI, the results of own investigations were presented. Within this study two series of melts of the ductile iron were made, introducing microadditions of the above mentioned elements to both unalloyed ductile iron and the ductile iron containing high levels of nickel and copper (the composition typical of ADI. Melts were conducted with iron-nickel-magnesium master alloy. Thermal analysis of the solidification process of the cast keel blocks was conducted, the heat treatment of the alloys was carried out, and then the effect of the introduced additions of boron and vanadium on the hardenability of the investigated cast iron was examined and evaluated.

  1. The spectrophotometric determination of boron in tourmalines

    Directory of Open Access Journals (Sweden)

    LJILJANA JAKSIC

    2005-02-01

    Full Text Available A procedure for the spectrophotometric determination of macro amounts of boron in tourmaline with azomethine H is described. The used tourmaline concentrate was obtained by magnetic separation and heavy-liquids purification of the schorl zone of pegmatite or granite aplite. The samples of tourmaline were decomposed by fusion with anhydrous sodium carbonate and taken up in dilute hydrochloric acid. The interfering effects of iron and aluminium were eliminated by masking with an EDTA – NTA solution. After pH adjustment, the boron was reacted with azomethine H and the absorbance of the obtained coloured complex was measured at 415 nm. The results are compared with those obtained by other procedures. The relative error of the determination was less than 3 %.

  2. Facile Synthesis of Ternary Boron Carbonitride Nanotubes

    Directory of Open Access Journals (Sweden)

    Luo Lijie

    2009-01-01

    Full Text Available Abstract In this study, a novel and facile approach for the synthesis of ternary boron carbonitride (B–C–N nanotubes was reported. Growth occurred by heating simple starting materials of boron powder, zinc oxide powder, and ethanol absolute at 1150 °C under a mixture gas flow of nitrogen and hydrogen. As substrate, commercial stainless steel foil with a typical thickness of 0.05 mm played an additional role of catalyst during the growth of nanotubes. The nanotubes were characterized by SEM, TEM, EDX, and EELS. The results indicate that the synthesized B–C–N nanotubes exhibit a bamboo-like morphology and B, C, and N elements are homogeneously distributed in the nanotubes. A catalyzed vapor–liquid–solid (VLS mechanism was proposed for the growth of the nanotubes.

  3. Boron-10 ABUNCL Models of Fuel Testing

    Energy Technology Data Exchange (ETDEWEB)

    Siciliano, Edward R.; Lintereur, Azaree T.; Kouzes, Richard T.; Ely, James H.

    2013-10-01

    The Department of Energy Office of Nuclear Safeguards and Security (NA-241) is supporting the project Coincidence Counting With Boron-Based Alternative Neutron Detection Technology at Pacific Northwest National Laboratory (PNNL) for the development of a 3He proportional counter alternative neutron coincidence counter. The goal of this project is to design, build and demonstrate a system based upon 10B-lined proportional tubes in a configuration typical for 3He-based coincidence counter applications. This report provides results from MCNP simulations of the General Electric Reuter-Stokes Alternative Boron-Based Uranium Neutron Coincidence Collar (ABUNCL) active configuration model with fuel pins previously measured at Los Alamos National Laboratory. A comparison of the GE-ABUNCL simulations and simulations of 3He based UNCL-II active counter (the system for which the GE-ABUNCL was targeted to replace) with the same fuel pin assemblies is also provided.

  4. Behavior of Disordered Boron Carbide under Stress

    Science.gov (United States)

    Fanchini, Giovanni; McCauley, James W.; Chhowalla, Manish

    2006-07-01

    Gibbs free-energy calculations based on density functional theory have been used to determine the possible source of failure of boron carbide just above the Hugoniot elastic limit (HEL). A range of B4C polytypes is found to be stable at room pressure. The energetic barrier for shock amorphization of boron carbide is by far the lowest for the B12(CCC) polytype, requiring only 6GPa≈P(HEL) for collapse under hydrostatic conditions. The results clearly demonstrate that the collapse of the B12(CCC) phase leads to segregation of B12 and amorphous carbon in the form of 2 3 nm bands along the (113) lattice direction, in excellent agreement with recent transmission electron microscopy results.

  5. Investigation of boron segregation in low carbon steel

    OpenAIRE

    J. Lis; Lis, A; Kolan, C.

    2011-01-01

    Traces of born in the range 0,002-0,009 % are usually added to many grades of steel. The effect of boron on phase transformations and hardenability of low carbon low alloy steels depends on the form of its behavior in solid solution either in segregations or in precipitations. Temperature and cooling rate determine the existence of boron segregations on grain boundaries. In present paper simulations of boron concentrations were calculated with computer programme DICTRA for low carbon 0,08 %C ...

  6. Boron/aluminum shelf for shuttle orbiter

    International Nuclear Information System (INIS)

    Boron/aluminum skins and channels were used in the fabrication of a prototype honeycomb sandwich avionics shelf. The avionic shelves are stiffness-critical and must be vibration tolerant. In conjunction with the shelf mounting system, they must isolate the avionics equipment from the severe vibration of the primary and secondary structure nearby. Design rationale, fabrication procedures, vibration test criteria and test results are presented. (9 fig) (U.S.)

  7. Boron Nitride Nanosheets for Metal Protection

    OpenAIRE

    Li, Lu Hua; Xing, Tan; Chen, Ying; Jones, Rob

    2015-01-01

    Although the high impermeability of graphene makes it an excellent barrier to inhibit metal oxidation and corrosion, graphene can form a galvanic cell with the underlying metal that promotes corrosion of the metal in the long term. Boron nitride (BN) nanosheets which have a similar impermeability could be a better choice as protective barrier, because they are more thermally and chemically stable than graphene and, more importantly, do not cause galvanic corrosion due to their electrical insu...

  8. Anomalous thermal conductivity of monolayer boron nitride

    Science.gov (United States)

    Tabarraei, Alireza; Wang, Xiaonan

    2016-05-01

    In this paper, we use nonequilibrium molecular dynamics modeling to investigate the thermal properties of monolayer hexagonal boron nitride nanoribbons under uniaxial strain along their longitudinal axis. Our simulations predict that hexagonal boron nitride shows an anomalous thermal response to the applied uniaxial strain. Contrary to three dimensional materials, under uniaxial stretching, the thermal conductivity of boron nitride nanoribbons first increases rather than decreasing until it reaches its peak value and then starts decreasing. Under compressive strain, the thermal conductivity of monolayer boron nitride ribbons monolithically reduces rather than increasing. We use phonon spectrum and dispersion curves to investigate the mechanism responsible for the unexpected behavior. Our molecular dynamics modeling and density functional theory results show that application of longitudinal tensile strain leads to the reduction of the group velocities of longitudinal and transverse acoustic modes. Such a phonon softening mechanism acts to reduce the thermal conductivity of the nanoribbons. On the other hand, a significant increase in the group velocity (stiffening) of the flexural acoustic modes is observed, which counteracts the phonon softening effects of the longitudinal and transverse modes. The total thermal conductivity of the ribbons is a result of competition between these two mechanisms. At low tensile strain, the stiffening mechanism overcomes the softening mechanism which leads to an increase in the thermal conductivity. At higher tensile strain, the softening mechanism supersedes the stiffening and the thermal conductivity slightly reduces. Our simulations show that the decrease in the thermal conductivity under compressive strain is attributed to the formation of buckling defects which reduces the phonon mean free path.

  9. Formation and Structure of Boron Nitride Nanotubes

    Institute of Scientific and Technical Information of China (English)

    Jiang ZHANG; Zongquan LI; Jin XU

    2005-01-01

    Boron nitride (BN) nanotubes were simply synthesized by heating well-mixed boric acid, urea and iron nitrate powders at 1000℃. A small amount of BN nanowires was also obtained in the resultants. The morphological and structural characters of the BN nanostructures were studied using transmission electron microscopy. Other novel BN nanostructures, such as Y-junction nanotubes and bamboo-like nanotubes, were simultaneously observed. The growth mechanism of the BN nanotubes was discussed briefly.

  10. Thermal conductivity of nanostructured boron nitride materials.

    Science.gov (United States)

    Tang, Chengchun; Bando, Yoshio; Liu, Changhong; Fan, Shoushan; Zhang, Jun; Ding, Xiaoxia; Golberg, Dmitri

    2006-06-01

    We have measured the thermal conductivity of bulky pellets made of various boron nitride (BN)-based nanomaterials, including spherical nanoparticles, perfectly structured, bamboo-like nanotubes, and collapsed nanotubes. The thermal conductivity strongly depends on the morphology of the BN nanomaterials, especially on the surface structure. Spherical BN particles have the lowest thermal conductivity while the collapsed BN nanotubes possess the best thermoconductive properties. A model was proposed to explain the experimental observations based on the heat percolation passage considerations. PMID:16722739

  11. Channeling of boron ions into silicon

    Energy Technology Data Exchange (ETDEWEB)

    Lecrosnier, D.; Paugam, J.; Gallou, J.

    1977-04-01

    Channeled and random distributions of boron ions implanted over the energy range 50 keV--1.8 MeV into silicon have been measured using the differential capacitance technique. When implantations are performed along the <110> or <111> axis, profiles exhibit a strong orientation dependance. The best channeled profiles shows that more than 70% of the implanted dose is in the channeled peak.

  12. Boron content of the Freetown drinking water

    International Nuclear Information System (INIS)

    A method is described for the analyses of water samples in the Freetown area of Sierra Leone for their boron concentrations. The method involves alpha counting during thermal neutron irradiation of the samples utilising the 10Ba(n,α)7Li reaction. The alpha counting is via a liquid scintillator which also incorporates the water samples. A detailed outline of the experimental setup is given and the results obtained from measurement on water samples presented. (author)

  13. Boron carbide synthesis by plasma spray process

    Czech Academy of Sciences Publication Activity Database

    Ctibor, Pavel; Brožek, Vlastimil; Hofman, R.

    Bari : Department of Chemistry, University of Bari, 2003 - (d'Agostino, R.; Favia, P.; Fracassi, F.; Palumbo, F.), s. - [International Symposium on Plasma Chemistry/16th./. Taormina (IT), 22.06.2003-27.06.2003] R&D Projects: GA ČR GA104/01/0149 Institutional research plan: CEZ:AV0Z2043910 Keywords : boron carbide , plasma spray, synthesis Subject RIV: BL - Plasma and Gas Discharge Physics

  14. Plasma Spray Deposition of Boron Carbide

    Czech Academy of Sciences Publication Activity Database

    Brožek, Vlastimil; Hofman, R.; Ctibor, Pavel; Hrabovský, Milan

    Praha : MAXDORF, s.r.o., 2002 - (Nitsch, K.; Rodová, M.). s. 11-12 [Development of Materials Science in Research and Education.. 10.09.2002-12.09.2002, Ostravice] R&D Projects: GA ČR GA104/01/0149; GA ČR GA202/01/1563 Institutional research plan: CEZ:AV0Z2043910 Keywords : plasma spray, boron carbide Subject RIV: BL - Plasma and Gas Discharge Physics

  15. Electron-Spin Resonance in Boron Carbide

    Science.gov (United States)

    Wood, Charles; Venturini, Eugene L.; Azevedo, Larry J.; Emin, David

    1987-01-01

    Samples exhibit Curie-law behavior in temperature range of 2 to 100 K. Technical paper presents studies of electron-spin resonance of samples of hot pressed B9 C, B15 C2, B13 C2, and B4 C. Boron carbide ceramics are refractory solids with high melting temperatures, low thermal conductives, and extreme hardnesses. They show promise as semiconductors at high temperatures and have unusually large figures of merit for use in thermoelectric generators.

  16. Functionalized boron-dipyrromethenes and their applications

    OpenAIRE

    M. Ravikanth, M; Vellanki,Lakshmi; Sharma,Ritambhara

    2016-01-01

    Vellanki Lakshmi, Ritambhara Sharma, Mangalampalli Ravikanth Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, IndiaAbstract: Boron-dipyrromethenes/BF2-dipyrrins (BODIPYs) are highly fluorescent dyes with a wide range of applications in various fields because of their attractive photophysical properties. One of the salient features of BODIPYs is that the properties of the BODIPY can be fine-tuned at will by selectively introducing the substituent(s) at the desired locati...

  17. Amorphous Carbon-Boron Nitride Nanotube Hybrids

    Science.gov (United States)

    Kim, Jae Woo (Inventor); Siochi, Emilie J. (Inventor); Wise, Kristopher E. (Inventor); Lin, Yi (Inventor); Connell, John (Inventor)

    2016-01-01

    A method for joining or repairing boron nitride nanotubes (BNNTs). In joining BNNTs, the nanotube structure is modified with amorphous carbon deposited by controlled electron beam irradiation to form well bonded hybrid a-C/BNNT structures. In repairing BNNTs, the damaged site of the nanotube structure is modified with amorphous carbon deposited by controlled electron beam irradiation to form well bonded hybrid a-C/BNNT structures at the damage site.

  18. Clinical aspects of boron neutron capture therapy

    International Nuclear Information System (INIS)

    Boron neutron capture therapy is potentially useful in treating malignant tumors of the central nervous system and is technically possible. Additional in vitro and in vivo testing is required to determine toxicities, normal tissue tolerances and tissue responses to treatment parameters. Adequate tumor uptake of the capture agent can be evaluated clinically prior to implementation of a finalized treatment protocol. Phase I and Phase II protocol development, clinical pharmacokinetic studies and neutron beam development

  19. Application of Cycloaddition Reactions to the Syntheses of Novel Boron Compounds

    OpenAIRE

    John A. Maguire; Hosmane, Narayan S; Yinghuai Zhu; Xiao Siwei

    2010-01-01

    This review covers the application of cycloaddition reactions in forming the boron-containing compounds such as symmetric star-shaped boron-enriched dendritic molecules, nano-structured boron materials and aromatic boronic esters. The resulting boron compounds are potentially important reagents for both materials science and medical applications such as in boron neutron capture therapy (BNCT) in cancer treatment and as drug delivery agents and synthetic intermediates for carbon-carbon cross-c...

  20. Electrochemical oxidation of oxalic acid in the presence of halides at boron doped diamond electrode

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Huitle, C.A. [University of Milan, Milan (Italy). Dept. of Analytical Chemistry]. E-mail: Carlos.Martinez@unimi.it; Ferro, S.; Battisti, A. de [University of Ferrara (Italy). Dept. of Chemistry. Lab. of Electrochemistry; Reyna, S.; Cerro-Lopez, M.; Quiroz, M.A. [Universidad de las Americas-Puebla, Puebla (Mexico). Dept. de Quimica y Biologia. Lab. de Electroquimica]. E-mail: marcoa.quiroz@udlap.mx

    2008-07-01

    Aim of this work is to discuss the electrochemical oxidation of oxalic acid (OA), analyzing the influence of NaCl and NaBr. Experiments were carried out at boron-doped diamond (BDD) electrodes, in alkaline media. BDD electrodes have a poor superficial adsorptivity so their great stability toward oxidation allows the reaction to take place with reactants and intermediates in a non-adsorbed state. The process is significantly accelerated by the presence of a halogen salt in solution; interestingly, the mediated process does not depend on applied current density. Based on the results, bromide was selected as a suitable mediator during OA oxidation at BDD. Br{sup -} primarily acts in the volume of the solution, with the formation of strong oxidants; while Cl{sup -} action has shown lower improvements in the OA oxidation rate at BDD respect to the results reported using Pt electrode. Finally, the parameters of removal efficiency and energy consumption for the electrochemical incineration of OA were calculated. (author)

  1. Considerations for boron neutron capture therapy studies

    International Nuclear Information System (INIS)

    Radiotherapy is indispensable as a mean to eradicate deeply or infiltrating tumor tissue that can not be removed surgically. Therefore, it is not selective and may also kill the surrounding health tissue. The principle of BNCT (Boron Neutron Capture Therapy) consist in targeting a tumor selectively with a boron-10 compound. This nuclide has a large capture cross section for thermal neutrons and the nuclear reaction and the delivered energy in locus will selective the tumor. Since its initial proposal in 1963 BNCT has made much progress, however it is not used in a routine treatment. In this work it was approached some complex procedures, as the obtention of selective boron compounds, the adequate set up of neutron beams, the biodistribution, the in vivo and in vitro studies, and also human patients treatments. This work provide fundamentals about BNCT to professional of different areas of knowledge since it comprises multidisciplinary study. It includes appendixes for the ones not related to the field for a better comprehension of the many aspects involved. It is also presented a glossary containing technical and basic aspects involved. It is also presented a glossary containing technical and basic terms referred in the work. (author). 174 refs, 1 fig, 12 apps

  2. Boron impregnation treatment of Eucalyptus grandis wood.

    Science.gov (United States)

    Dhamodaran, T K; Gnanaharan, R

    2007-08-01

    Eucalyptus grandis is suitable for small timber purposes, but its wood is reported to be non-durable and difficult to treat. Boron compounds being diffusible, and the vacuum-pressure impregnation (VPI) method being more suitable for industrial-scale treatment, the possibility of boron impregnation of partially dry to green timber was investigated using a 6% boric acid equivalent (BAE) solution of boric acid and borax in the ratio 1:1.5 under different treatment schedules. It was found that E. grandis wood, even in green condition, could be pressure treated to desired chemical dry salt retention (DSR) and penetration levels using 6% BAE solution. Up to a thickness of 50mm, in order to achieve a DSR of 5 kg/m(3) boron compounds, the desired DSR level as per the Indian Standard for perishable timbers for indoor use, it was found that neither the moisture content of wood nor the treatment schedule posed any problem as far as the treatability of E. grandis wood was concerned. PMID:17046244

  3. Analysis of heterogeneous boron dilution sequences

    International Nuclear Information System (INIS)

    In the scope of the international SETH project (focused on boron dilution sequences), the Spanish Nuclear Regulatory Commission (CSN) and the electric energy industry of Spain (UNESA) have promoted in Spain a national project for the analysis and application of the SETH results to the Spanish nuclear power plants. As part of this project, our team has performed a review and analysis of the different sequences that could lead to a boron dilution in the primary circuit of a pressurized water reactor (PWR). On a first stage of the project we have analyzed the different sequences and the phenomenologies that could lead to inadvertent boron dilution in the primary system (about twenty different sequences are described in the literature), the core damage frequency of each one, the projects and experiments carried out on several experimental facilities and the modifications performed in order to avoid or to mitigate this kind of sequences. On a second one we have reviewed the relation between the operating procedures, Westinghouse design reactors, and this kind of sequences. Finally we have analyzed the simulation problems of these kind of sequences and performed several numerical simulations with the TRAC-M (TRACE) code applied to numerical benchmarks and also to a 3D vessel model. (author)

  4. Boron-containing nuclear safety materials

    International Nuclear Information System (INIS)

    As insurance against reactor runaway or other unplanned excursions, gas-cooled, graphite-moderated reactors are provided with a secondary shut-down mechanism which serves as a back-up to the primary control rod system. This back-up includes a hopper located above fuel channels in the core, equipped with a quick discharge mechanism, which is filled with boron-containing spheres. In an emergency, this hopper discharges the spheres which then cascade down the channels and ''poison'' the uranium fission reaction by absorbing thermal neutrons - the propagators of the chain reaction. Within six months time, a process was successfully developed based on silicon carbide reaction-bonding, which yielded a strong, hard, oxidation-resistant, boron-containing shut-down ball. Test materials were exposed to water saturated argon for three hours at each of several temperatures. While normal boron carbide-graphite balls were completely vaporized, the Cerashield balls remained basically unaffected. Had the reactor at Chernobyl been outfitted with Cerashield shut-down balls, it might never have become famous

  5. Boron dose enhancement for Cf-252 brachytherapy

    International Nuclear Information System (INIS)

    Full text: Monte Carlo modelling of a Cf-252 source in water and in tissue has shown that there is a significant therapeutic advantage obtained if B-10 is present in the tumour cells. This study analyses the advantage in terms of therapeutic margin, defined as the distance from the border of the treatment volume where boron-loaded tumour cells will receive a therapeutic dose. Calculations were made with MCNP version 4a on a Pentium 60 MHz computer. Large voxel sizes allowed 70 minute runs to achieve statistical uncertainties of 5% or less for 100,000 source neutrons. Later runs with smaller voxels confirmed the accuracy of the initial calculations. Calculations were made for treatment volume radii up to 11 cm and 30 ppm boron-10. The therapeutic margin for radii in the range 3-9 cm is approximately 10% of the tumour radius. This results in a 30% increase in the volume inside which peripheral tumour cells may receive a therapeutic dose. The median therapeutic ratio within the therapeutic margin varied from 1.05 at 3 cm up to 1.25 at 10 cm. Thus there is little benefit for less advanced tumours with thickness less than 3 cm. However, cervical cancer frequently presents in an advanced state in Southeast Asia and in Aboriginal communities in Australia, partially attributable to low Pap smear screening rates. These conclusions support the development and testing of boron compounds in in vitro and in vivo models for cervical cancer

  6. Boron removal from molten silicon using sodium-based slags

    Institute of Scientific and Technical Information of China (English)

    Yin Changhao; Hu Bingfeng; Huang Xinming

    2011-01-01

    Slag refining,as an important option for boron removal to produce solar grade silicon (SOG-Si) from metallurgical grade silicon (MG-Si),has attracted increasing attention.In this paper,Na2CO3-SiO2 systems were chosen as the sodium-based refining slag materials for boron removal from molten silicon.Furthermore,the effect of Al2O3 addition for boron removal was studied in detail,which showed that an appropriate amount of Al2O3 can help retention of the basicity of the slags,hence improving the boron removal rate.

  7. Boron distribution in normal and impaired vascular tissue

    International Nuclear Information System (INIS)

    The microdistribution of boron compounds and the response to Boron Neutron Capture Therapy (BNCT) in normal or impaired vascular structures have not been fully investigated. In this study, we measured the boron concentrations in rat normal vascular tissue for a potential application of BNCT to prevent restenosis following carotid stenting. Male inbred Wistar rats, 6 weeks of age, were used. After intravenous administration of boron compounds (BSH, BPA, or boron porphyrins), rats were killed at either 1, 2, or 3 hours, and the aortic arch, vena cava, blood, liver, kidney, muscle, skin, and brain were collected for measuring boron concentrations in the sample. Boron concentrations in vascular structures, although dependent on the time after administration, are higher than those in blood and surrounding tissue such as muscle or skin. Given that boron compounds such as boron porphyrins are incorporated into arterial tissues, and more into impaired than in normal intima, BNCT might be effective in inhibiting restenosis following carotid artery stenting or coronary artery stenting. (author)

  8. Boron isotope fractionation during brucite deposition from artificial seawater

    OpenAIRE

    J. Xiao; Xiao, Y. K.; Liu, C. Q.; Z. D. Jin

    2011-01-01

    Experiments involving boron incorporation into brucite (Mg(OH)2) from magnesium-free artificial seawater with pH values ranging from 9.5 to 13.0 were carried out to better understand the incorporation behavior of boron into brucite and the influence of it on Mg/Ca-SST proxy and δ11B-pH proxy. The results show that both the concentration of boron in deposited brucite ([B]d) and its boron partition coefficient (

  9. Boron isotope fractionation during brucite deposition from artificial seawater

    OpenAIRE

    J. Xiao; Xiao, Y. K.; Liu, C. Q.; Z. D. Jin

    2011-01-01

    Experiments involving boron incorporation into brucite (Mg(OH)2) from magnesium-free artificial seawater with pH values ranging from 9.5 to 13.0 were carried out to better understand the incorporation behavior of boron into brucite and the influence of it on Mg/Ca-SST proxy and δ11B-pH proxy. The results show that both the concentration of boron in deposited brucite ([B]d) and its boron partition coefficient (Kd) between deposited brucite and final seawater are control...

  10. Combustion synthesis of boron carbide - a spectroscopic studies

    International Nuclear Information System (INIS)

    Boron Carbide is one of the hardest materials known, ranking third behind diamond and cubic boron nitride. It is the hardest material produced in tonnage quantities. Boron carbide (BxCx) enriched in the 10B isotope is used as a control rod material in the nuclear industry due to its high neutron absorption cross section and other favorable physico-chemical properties. Conventional methods of preparation of boron carbide are energy intensive processes accompanied by huge loss of boron. Attempts were made at IGCAR Kalpakkam to develop energy efficient and cost effective methods to prepare boron carbide. Nuclear applications of boron carbide include shielding, control rod and shut down pellets. Within control rods, boron carbide is often powdered, to increase its surface area. The products of the gel combustion and microwave synthesis experiments were characterized for phase purity by X-ray diffraction (XRD). The carbide formation was ascertained using finger-print spectroscopy of Fourier transform infrared (FTIR). Samples of pyrolized/microwave heated powder were characterized for surface morphology using electron microscope (SEM). The present work shows the recent advances in understanding of structural and chemical variation in boron carbide and their influence on morphology, optical and vibrational property result discussed in details. (author)

  11. Dosage of boron traces in graphite, uranium and beryllium oxide

    International Nuclear Information System (INIS)

    The problem of the dosage of the boron in the materials serving to the construction of nuclear reactors arises of the following way: to determine to about 0,1 ppm close to the quantities of boron of the order of tenth ppm. We have chosen the colorimetric analysis with curcumin as method of dosage. To reach the indicated contents, it is necessary to do a previous separation of the boron and the materials of basis, either by extraction of tetraphenylarsonium fluoborate in the case of the boron dosage in uranium and the beryllium oxide, either by the use of a cations exchanger resin of in the case of graphite. (M.B.)

  12. Doping Silicon Wafers with Boron by Use of Silicon Paste

    Institute of Scientific and Technical Information of China (English)

    Yu Gao; Shu Zhou; Yunfan Zhang; Chen Dong; Xiaodong Pi; Deren Yang

    2013-01-01

    In this work we introduce recently developed silicon-paste-enabled p-type doping for silicon.Boron-doped silicon nanoparticles are synthesized by a plasma approach.They are then dispersed in solvents to form silicon paste.Silicon paste is screen-printed at the surface of silicon wafers.By annealing,boron atoms in silicon paste diffuse into silicon wafers.Chemical analysis is employed to obtain the concentrations of boron in silicon nanoparticles.The successful doping of silicon wafers with boron is evidenced by secondary ion mass spectroscopy (SIMS) and sheet resistance measurements.

  13. ADSORPTION POTENTIAL OF UNMODIFIED RICE HUSK FOR BORON REMOVAL

    OpenAIRE

    Hasfalina Che Man,; Wei Hong Chin,; Maryam Rahmati Zadeh,; Mohd Rashid Mohd Yusof

    2012-01-01

    A batch study of boron removal from aqueous solutions by adsorption using rice husk was carried out. The effect of selected parameters such as particle size, pH, adsorbent dosage, and initial concentration of adsorbate on boron removal was investigated in the study. Results showed that the maximum boron removal was obtained with the rice husk particle size between 0.425 mm and 1.0 mm at pH 5. Boron removal was increased with an increasing amount of adsorbent dosage but decreased as the initia...

  14. Molecular structure of the complex of octano-8-lactam with magnesium bromide

    Czech Academy of Sciences Publication Activity Database

    Kříž, Jaroslav; Dybal, Jiří; Kurková, Dana; Prokopová, I.; Hroch, Z.

    2001-01-01

    Roč. 202, č. 17 (2001), s. 3371-3378. ISSN 1022-1352 R&D Projects: GA AV ČR KSK2050602; GA ČR GA106/98/0699 Institutional research plan: CEZ:AV0Z4050913 Keywords : anionic polymerization * coordination * magnesium bromide Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.629, year: 2001

  15. Microwave-Enhanced Cross-Coupling Reactions Involving Alkynyltrifluoroborates with Aryl Bromides

    Directory of Open Access Journals (Sweden)

    George W. Kabalka

    2013-01-01

    Full Text Available Palladium-catalyzed alkynylation has emerged as one of the most reliable methods for the synthesis of alkynes which are often used in natural product syntheses and material science. An efficient method for coupling alkynyltrifluoroborates with various aryl bromides in the presence of a palladium catalyst has been developed using microwave irradiation. The microwave reactions are rapid and efficient.

  16. Reduced rates and alternatives to methyl bromide for snapdragon production in Florida

    Science.gov (United States)

    A field trial was conducted to evaluate soil solarization, Midas™ (iodomethane:chloropicrin 50:50, Arysta LifeScience Corp., Cary, NC) and different rates and formulations of methyl bromide under standard and metalized films for the production of snapdragon (Antirrhinum majus) in Martin County, Flor...

  17. Effect of increasing bromide concentration on toxicity in treated drinking water.

    Science.gov (United States)

    Sawade, Emma; Fabris, Rolando; Humpage, Andrew; Drikas, Mary

    2016-04-01

    Research is increasingly indicating the potential chronic health effects of brominated disinfection by-products (DBPs). This is likely to increase with elevated bromide concentrations resulting from the impacts of climate change, projected to include extended periods of drought and the sudden onset of water quality changes. This will demand more rigorous monitoring throughout distribution systems and improved water quality management at water treatment plants (WTPs). In this work the impact of increased bromide concentration on formation of DBPs following conventional treatment and chlorination was assessed for two water sources. Bioanalytical tests were utilised to determine cytotoxicity of the water post disinfection. Coagulation was shown to significantly reduce the cytotoxicity of the water, indicating that removal of natural organic matter DBP precursors continues to be an important factor in drinking water treatment. Most toxic species appear to form within the first half hour following disinfectant addition. Increasing bromide concentration across the two waters was shown to increase the formation of trihalomethanes and shifted the haloacetic acid species distribution from chlorinated to those with greater bromine substitution. This correlated with increasing cytotoxicity. This work demonstrates the challenges faced by WTPs and the possible effects increasing levels of bromide in source waters could have on public health. PMID:27105403

  18. Iodine transfer through mother´s milk: the influence of bromide

    Czech Academy of Sciences Publication Activity Database

    Pavelka, Stanislav

    Oxford : Academic Press, 2009 - (Preedy, V.; Burrow, G.; Watson, R.), s. 199-206 ISBN 978-0-12-374135-6 Grant ostatní: EC(XE) LSHG-CT-2004-511978 Institutional research plan: CEZ:AV0Z50110509 Keywords : bromide * iodine * mother’s milk Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition

  19. Effects of intraoperative magnetic resonance imaging on the neuromuscular blockade of vecuronium bromide in neurosurgery

    International Nuclear Information System (INIS)

    The effects of intraoperative magnetic resonance (iMR) imaging on the neuromuscular blockade of vecuronium bromide were investigated in neurosurgery. Fifty patients with American Society of Anesthesiologists grades I-II scheduled for craniotomy operation were divided into two groups (n=25 each) with no difference in demographic data: the iMR imaging group and control group. Train-of-four (TOF) stimulation through an accelerometer was used to monitor onset, maintenance, and recovery of muscle relaxation caused by vecuronium. Vecuronium bromide was intravenously injected after anesthesia induction. The dosage of vecuronium bromide in the iMR imaging group was larger than in the control group, but not significantly. Duration of vecuronium bromide administration and operation time were significantly longer in the iMR imaging group than in the control group. Time from drug discontinuation to operation termination, and to return to neurosurgery intensive care unit were not different. Time taken by first twitch (T1) in response to TOF stimulation to recover by 25%, and muscle relaxant recovery index were significantly greater in the control group than in the iMR imaging group. The body temperature of the patients increased gradually in the iMR imaging group but decreased in the control group. iMR imaging can prolong the operation time, increase the body temperature of the patient, and remarkably shorten the clinical action time and muscle relaxation recovery index of vecuronium. (author)

  20. Efficient loading of primary alcohols onto a solid phase using a trityl bromide linker

    DEFF Research Database (Denmark)

    Crestey, François; Ottesen, Lars Korsgaard; Jaroszewski, Jerzy Witold;

    2008-01-01

    The Letter describes an improved, rapid and mild strategy for the loading of primary alcohols onto a polystyrene trityl resin via a highly reactive trityl bromide linker. This protocol facilitates an efficient resin loading even of acid-sensitive or heat-labile alcohols, which otherwise require...

  1. 76 FR 29238 - Methyl Bromide; Cancellation Order for Registration Amendments To Terminate Certain Soil Uses

    Science.gov (United States)

    2011-05-20

    ... provided, EPA received no comments in response to the February 9, 2011, Federal Register notice (76 FR 7200... AGENCY Methyl Bromide; Cancellation Order for Registration Amendments To Terminate Certain Soil Uses... for the amendments to terminate soil uses, voluntarily requested by the registrants and accepted...

  2. Strontium and bromide as tracers in X-ray microanalysis of biological tissue

    International Nuclear Information System (INIS)

    Since energy dispersive X-ray microanalysis cannot distinguish between isotopes of the same element, alternative methods have to be used to get information similar to that obtained in experiments with radioactive tracers. In the present study, strontium was used as a tracer for calcium, and bromide as a tracer for chloride. Rats were injected with strontium chloride in vivo, and the uptake of strontium in the acinar cells of the submandibular gland was studied. Eventually a Sr/Ca ratio of 0.3 was reached. In some animals, secretion of mucus had been elicited by stimulation with isoproterenol 4 h prior to injection of strontium chloride. Exchange of calcium for strontium was enhanced by prior injection with isoproterenol. In a second experiment, rats were injected with sodium bromide, and the uptake of bromide by the submandibular acinar cells was followed in time, both in pilocarpine-stimulated and unstimulated glands. Under the experimental conditions, bromide was rapidly taken up by the cells, and the cellular Br/Cl ratio was close to that found in serum. Submandibular glands take up Br somewhat faster than other tissues (liver, heart muscle, skeletal muscle). The uptake of Br in pancreatic acinar cells was studied in vitro. These experiments showed a 1:1 ratio (molar) exchange of Cl for Br

  3. COMPARISON OF ONSET TIME, DURATION OF ACTION AND INTUBATING CONDITION SACHIEVED WITH SUXAMETHONIUM AND ROCURONIUM BROMIDE

    OpenAIRE

    Ajit P; Alok P; Devendra Singh

    2013-01-01

    Adverse event profile ofSuxamethonium which is still the relaxant of choice to facilitate tracheal intubation inspired us to conduct a study in which we compared Onset time, Duration of Action and Intubating Conditions Achieved with Suxametho nium and Rocuronium Bromide with the Help of TOF Guard. AIMS : W e compared the onset of relaxation time, intubating condition, and duration of action, the ...

  4. Hydrophobic Ion-Pairing of Low Molecular Weight Heparin with Cetyltrimethylammonium Bromide

    OpenAIRE

    Nermin E. Eleraky; Mohamed, Dina F; Mohamed A. Attia; Pauletti, Giovanni M.

    2015-01-01

    Purpose: Unfavorable physicochemical properties of low molecular weight heparin (LMWH) restrict membrane permeation of this therapeutic macromolecule to paracellular passive diffusion. To augment LMWH flux across biological membranes using contributions of transcellular transport mechanisms, this study explored formation of electrostatically stabilized association complexes via ion-pairing with the lipophilic cetyltrimethylammonium bromide (CTAB). Methods: LMWH/CTAB interactions were assessed...

  5. Ozone decomposition under the irradiation of 253.7 nm in the presence of methyl bromide

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this paper the mechanism and kinetic of ozone decomposition under the irradiation of 253.7 nm UV-light were studied.The quantum yield of the ozone depletion in the presence of methyl bromide is further determined and a reaction model is provided to explain the experimental fact.

  6. The stereoselective synthesis of dienes through dehalogenative homocoupling of terminal alkenyl bromides on Cu(110).

    Science.gov (United States)

    Sun, Qiang; Cai, Liangliang; Ma, Honghong; Yuan, Chunxue; Xu, Wei

    2016-05-21

    We have successfully achieved the stereoselective synthesis of a specific cis-diene moiety through a dehalogenative homocoupling of alkenyl bromides on the Cu(110) surface, where the formation of a cis-form organometallic intermediate is the key to such a stereoselectivity as determined by DFT calculations. PMID:27063567

  7. Combinatorial electrochemistry using metal nanoparticles: from proof-of-concept to practical realisation for bromide detection.

    Science.gov (United States)

    Sljukić, Biljana; Baron, Ronan; Salter, Chris; Crossley, Alison; Compton, Richard G

    2007-05-01

    Principles and practical application of combinatorial electrochemistry in search for new electroactive materials in electroanalysis have been explored. Nanoparticles of three different metals: silver, gold and palladium have been independently synthesized on the glassy carbon spherical powder surface by electroless deposition process and characterized using both spectroscopic and electrochemical techniques. These three materials were then combined together onto basal plane pyrolytic graphite electrode surface and the application of the combinatorial approach to find the electrode material for bromide detection as model target analyte was demonstrated. The component electroactive for bromide detection was next identified and it was found that silver nanoparticles were the active ones. A composite electrode based on silver nanoparticle modified glassy carbon powder and epoxy resin was then fabricated and it was found to allow accurate determination of bromide. The electroactivity for the bromide determination of the composite electrode was compared with that of a bulk silver electrode and it was shown that the composite electrode is very efficient with a comparable electroactivity with only a portion of precious metals being used for its construction. PMID:17416224

  8. Palladium-catalyzed carbonylative sonogashira coupling of aryl bromides using near stoichiometric carbon monoxide

    DEFF Research Database (Denmark)

    Neumann, Karoline T.; Laursen, Simon R.; Lindhardt, Anders T.;

    2014-01-01

    A general procedure for the palladium-catalyzed carbonylative Sonogashira coupling of aryl bromides is reported, using near stoichiometric amounts of carbon monoxide. The method allows a broad substrate scope in moderate to excellent yields. The formed alkynone motive serves as a platform for...

  9. Once-daily glycopyrronium bromide, a long-acting muscarinic antagonist, for chronic obstructive pulmonary disease

    DEFF Research Database (Denmark)

    Ulrik, Charlotte Suppli

    2012-01-01

    Long-acting bronchodilators are central in the pharmacological management of patients with chronic obstructive pulmonary disease (COPD). The aim of this systematic review is to provide an overview of the studies evaluating the safety and clinical efficacy of inhaled glycopyrronium bromide, a nove...

  10. Palladium-Catalyzed Carbonylation of Aryl Bromides with N-Substituted Cyanamides

    DEFF Research Database (Denmark)

    Lian, Zhong; Friis, Stig D.; Lindhardt, Anders T.;

    2014-01-01

    The palladium(0)-catalyzed three-component coupling reaction of aryl bromides, carbon monoxide, and N-alkyl cyan­amides has been developed employing a two-chamber system with ex situ generation of carbon monoxide from a silacarboxylic acid. The reactions proceeded well and were complete with a...

  11. Use of Br-82 and I-131 radionuclides in studies of goitrogenic effects of exogenous bromide

    Czech Academy of Sciences Publication Activity Database

    Pavelka, Stanislav

    2012-01-01

    Roč. 291, č. 2 (2012), s. 379-383. ISSN 0236-5731 R&D Projects: GA ČR(CZ) GA304/08/0256 Institutional research plan: CEZ:AV0Z50110509 Keywords : bromide * goitrogenic effect * iodine radionuclides * thyroid hormone Subject RIV: ED - Physiology Impact factor: 1.467, year: 2012

  12. Radioiodine tracers as useful tools in studies of thyrotoxic effects of exogenous bromide and perchlorate ions

    Czech Academy of Sciences Publication Activity Database

    Pavelka, Stanislav

    2012-01-01

    Roč. 291, č. 2 (2012), s. 405-408. ISSN 0236-5731 R&D Projects: GA ČR(CZ) GA304/08/0256 Institutional research plan: CEZ:AV0Z50110509 Keywords : bromide * perchlorate * radioiodine tracer * thyroid hormone Subject RIV: ED - Physiology Impact factor: 1.467, year: 2012

  13. Methyl Bromide Alternatives Area-Wide Pest Management Project - South Atlantic Progress Report

    Science.gov (United States)

    Protocols and Standard Operational Procedures (SOPs) were developed for collecting environmental and soil edaphic information during and after application of methyl bromide alternatives. Parameters measured included soil moisture, soil bulk density, percent moisture at field capacity (-0.3 bars wat...

  14. Bromate formation from bromide oxidation by the UV/persulfate process.

    Science.gov (United States)

    Fang, Jing-Yun; Shang, Chii

    2012-08-21

    Bromate formation from bromide oxidation by the UV/persulfate process was investigated, along with changes in pH, persulfate dosages, and bromide concentrations in ultrapure water and in bromide-spiked real water. In general, the bromate formation increased with increasing persulfate dosage and bromide concentration. The bromate formation was initiated and primarily driven by sulfate radicals (SO(4)(•-)) and involved the formation of hypobromous acid/hypobromite (HOBr/OBr(-)) as an intermediate and bromate as the final product. Under the test conditions, the rate of the first step driven by SO(4)(•-) is slower than that of the second step. Direct UV photolysis of HOBr/OBr(-) to form bromate and the photolysis of bromate are insignificant. The bromate formation was similar for pH 4-7 but decreased over 90% with increasing pH from 7 to above 9. Less bromate was formed in the real water sample than in ultrapure water, which was primarily attributable to the presence of natural organic matter that reacts with bromine atoms, HOBr/OBr(-) and SO(4)(•-). The extent of bromate formation and degradation of micropollutants are nevertheless coupled processes unless intermediate bromine species are consumed by NOM in real water. PMID:22831804

  15. Critical Range of Soil Boron for Prognosis of Boron Deficiency in Oilseed Rape

    Institute of Scientific and Technical Information of China (English)

    WEIYOUZHANG

    2001-01-01

    Relationships between seed yields of oilseed rape(Brassica napus L.) and extractable boron concen-trations in three soil layers(A,P and W) were investigated through ten experiments on three types of soils(Alluvic Entisols,Udic Ferrisols and Sagnic Anthrosols) in northern,Western and middle Zhejing Province.Among several mathematical models used to described the relationships,the polynomial equation,y=a+bx+cx2+dx3,where y is the yield of oilseed rape seed and x the extractable boron concentration in P layer of soil,was the best one.The critical range of the concentrations corresponding to 90% of the maximum oilseed rape yield was 0.40-0.52 mg kg-1,The extractable boron concentration of the P layers of the soils was the most stable,The critical range determined was verified through the production practices of oilseed rape in Zhejiang and Anhui provinces.

  16. Critical Range of Soil Boron for Prognosis of Boron Deficiency in Oilseed Rape

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Relationships between seed yields of oilseed rape (Brassica napus L.) and extractable boron concen- trations in three soil layers (A, P and W) were investigated through ten experiments on three types of soils (Alluvic Entisols, Udic Ferrisols and Stagnic Anthrosols) in northern, western and middle Zhejiang Province. Among several mathematical models used to described the relationships, the polynomial equation, y = a + bx + cx2 + dx3, where y is the yield of oilseed rape seed and x the extractable boron concentration in P layer of soil, was the best one. The critical range of the concentrations corresponding to 90% of the maximum oilseed rape yield was 0.40~0.52 mg kg-1. The extractable boron concentration of the P layers of the soils was the most stable. The critical range determined was verified through the production practices of oilseed rape in Zhejiang and Anhui provinces.

  17. Mechanisms of the boron carbide and boron nitride preferred sputtering by low energy ions bombardment

    International Nuclear Information System (INIS)

    The ion irradiation of BN and B4C leads to enriching of the materials with the lighter component - borons as the experiment shows . With a view to explain this effect sputtering of BN and B4C under the irradiation by the He+ and Ar+ ions with the energy E0=0,5-5 keV has been calculated with computer modelling and the real structure of BN has been considered. In the case of B4C the calculations have been carried with Monte-Carlo code. It was shown that enriching of BN by boron may be accounted for building up the molecules N2 on the irradiated surface and their desorbing. The enriching of B4C with boron results from the difference of the binding energy of the B and C atoms. (author). 10 refs., 5 tabs

  18. Production process for boron carbide coated carbon material and boron carbide coated carbon material obtained by the production process

    International Nuclear Information System (INIS)

    A boron carbide coated carbon material is used for a plasma facing material of a thermonuclear reactor. The surface of a carbon material is chemically reacted with boron oxide to convert it into boron carbide. Then, it is subjected to heat treatment at a temperature of not lower than 1600degC in highly evacuated or inactive atmosphere to attain a boron carbide coated carbon material. The carbon material used is an artificial graphite or a carbon fiber reinforced carbon composite material. In the heat treatment, when the atmosphere is in vacuum, it is highly evacuated to less than 10Pa. Alternatively, in a case of inactive atmosphere, argon or helium gas each having oxygen and nitrogen content of not more than 20ppm is used. With such procedures, there can be obtained a boron carbide-coated carbon material with low content of oxygen and nitrogen impurities contained in the boron carbide coating membrane thereby hardly releasing gases. (I.N.)

  19. Lateral gas phase diffusion length of boron atoms over Si/B surfaces during CVD of pure boron layers

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadi, V., E-mail: V.Mohammadi@tudelft.nl; Nihtianov, S. [Department of Microelectronics, Delft University of Technology, Mekelweg 4, 2628 CD, Delft (Netherlands)

    2016-02-15

    The lateral gas phase diffusion length of boron atoms, L{sub B}, along silicon and boron surfaces during chemical vapor deposition (CVD) using diborane (B{sub 2}H{sub 6}) is reported. The value of L{sub B} is critical for reliable and uniform boron layer coverage. The presented information was obtained experimentally and confirmed analytically in the boron deposition temperature range from 700 °C down to 400 °C. For this temperature range the local loading effect of the boron deposition is investigated on the micro scale. A L{sub B} = 2.2 mm was determined for boron deposition at 700 °C, while a L{sub B} of less than 1 mm was observed at temperatures lower than 500 °C.

  20. Removal of bromide and iodide anions from drinking water by silver-activated carbon aerogels.

    Science.gov (United States)

    Sánchez-Polo, M; Rivera-Utrilla, J; Salhi, E; von Gunten, U

    2006-08-01

    The aim of this study is to analyze the use of Ag-doped activated carbon aerogels for bromide and iodide removal from drinking water and to study how the activation of Ag-doped aerogels affects their behavior. It has been observed that the carbonization treatment and activation process of Ag-doped aerogels increased the surface area value ( [Formula: see text] ), whereas the volume of meso-(V(2)) and macropores (V(3)) decreased slightly. Chemical characterization of the materials revealed that carbonization and especially activation process considerably increased the surface basicity of the sample. Original sample (A) presented acidic surface properties (pH(PZC)=4.5) with 21% surface oxygen, whereas the sample that underwent activation showed mainly basic surface chemical properties (pH(PZC)=9.5) with only 6% of surface oxygen. Carbonization and especially, activation process considerable increased the adsorption capacity of bromide and iodide ions. This would mainly be produced by (i) an increase in the microporosity of the sample, which increases Ag-adsorption sites available to halide anions, and (ii) a rise of the basicity of the sample, which produces an increase in attractive electrostatic interactions between the aerogel surface, positively charged at the working pH (pH(solution)water treatment, adsorption of bromide and iodide was studied under dynamic conditions using waters from Lake Zurich. Results obtained showed that the carbonization and activation processes increased the adsorptive capacity of the aerogel sample. However, results showed that the adsorption capacity of the aerogel samples studied was considerably lower in water from Lake Zurich. Results showed X(0.02) (amount adsorbed to initial breakthrough) values of 0.1 and 4.3 mg/g for chloride anion and dissolved organic carbon (DOC), respectively, during bromide adsorption process in water from Lake Zurich. This indicates that the adsorptive capacity reduction observed may be due to (i) blocking

  1. Suppression of IL-8 production from airway cells by tiotropium bromide in vitro

    Directory of Open Access Journals (Sweden)

    Suzaki I

    2011-09-01

    Full Text Available Isao Suzaki1, Kazuhito Asano2, Yusuke Shikama3, Taisuke Hamasaki1, Ayako Kanei1, Harumi Suzaki11Department of Otorhinolaryngology, School of Medicine, Showa University, Tokyo, Japan; 2Division of Physiology, School of Nursing and Rehabilitation Sciences, Showa University, Yokohama, Japan; 3Department of Respiratory Diseases, Showa University Northern Yokohama Hospital, Yokohama, JapanBackground: COPD is characterized by persistent and progressive airway inflammation. Although neutrophilic airway inflammation is generally accepted to be a major factor in the pathogenesis of COPD, the influence of the agents used for the treatment of COPD on neutrophil functions such as chemotaxis is not fully understood.Purpose: The present study aimed to examine the influence of tiotropium bromide on the production of interleukin (IL-8 from human airway epithelial cells and lung fibroblasts (LFs after lipopolysaccharide (LPS stimulation in vitro.Methods: BEAS-2B cells, human bronchial epithelial cell line, and LFs, at a concentration of 5 × 105 cells/mL, were stimulated with LPS in the presence of various concentrations of tiotropium bromide. IL-8 in culture supernatants was examined by enzyme-linked immunosorbent assay (ELISA. IL-8 messenger ribonucleic acid (mRNA expression was examined by real-time polymerase chain reaction. The influence of tiotropium bromide on LPS-induced signaling pathways was also analyzed by examining nuclear factor-kappa (NF-κB activation and signaling protein phosphorylation by ELISA.Results: Tiotropium bromide at >15 pg/mL inhibited IL-8 production from both BEAS-2B cells and LFs after LPS stimulation. Tiotropium bromide also suppressed IL-8 mRNA expression through the inhibition of NF-κB activation and signaling protein, extracellular-signal-regulated kinase 1/2, and c-Jun N-terminal kinase, phosphorylation.Conclusion: The present results strongly suggest that tiotropium bromide exerts the inhibitory effect on neutrophilic

  2. Characterization of soluble bromide measurements and a case study of BrO observations during ARCTAS

    Directory of Open Access Journals (Sweden)

    J. Liao

    2012-02-01

    Full Text Available A focus of the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS mission was examination of bromine photochemistry in the spring time high latitude troposphere based on aircraft and satellite measurements of bromine oxide (BrO and related species. The NASA DC-8 aircraft utilized a chemical ionization mass spectrometer (CIMS to measure BrO and a mist chamber (MC to measure soluble bromide. We have determined that the MC detection efficiency to molecular bromine (Br2, hypobromous acid (HOBr, bromine oxide (BrO, and hydrogen bromide (HBr as soluble bromide (Br was 0.9±0.1, 1.06+0.30/−0.35, 0.4±0.1, and 0.95±0.1, respectively. These efficiency factors were used to estimate soluble bromide levels along the DC-8 flight track of 17 April 2008 from photochemical calculations constrained to in situ BrO measured by CIMS. During this flight, the highest levels of soluble bromide and BrO were observed and atmospheric conditions were ideal for the space-borne observation of BrO. The good agreement (R2 = 0.76; slope = 0.95; intercept = −3.4 pmol mol−1 between modeled and observed soluble bromide, when BrO was above detection limit (>2 pmol mol−1 under unpolluted conditions (NO<10 pmol mol−1, indicates that the CIMS BrO measurements were consistent with the MC soluble bromide and that a well characterized MC can be used to derive mixing ratios of some reactive bromine compounds. Tropospheric BrO vertical column densities (BrOVCD derived from CIMS BrO observations compare well with BrOTROPVCD from OMI on 17 April 2008.

  3. Determination of isotopic composition of boron in boron carbide by TIMS and PIGE: an inter-comparison study

    International Nuclear Information System (INIS)

    The paper reports a comparison of results on the determination of isotopic composition of boron in boron carbide (B4C) samples by Thermal Ionisation Mass Spectrometry (TIMS) and Particle Induced Gamma ray Spectrometry (PIGE). B4C samples having varying boron isotopic composition (natural, enriched with respect to 10B) and their synthetic mixtures) have been analysed by both the techniques. The 10B atom% was found to be in the range of 20-67%. (author)

  4. Structure and local chemical properties of boron-terminated tetravacancies in hexagonal boron nitride.

    Science.gov (United States)

    Cretu, Ovidiu; Lin, Yung-Chang; Koshino, Masanori; Tizei, Luiz H G; Liu, Zheng; Suenaga, Kazutomo

    2015-02-20

    Imaging and spectroscopy performed in a low-voltage scanning transmission electron microscope are used to characterize the structure and chemical properties of boron-terminated tetravacancies in hexagonal boron nitride. We confirm earlier theoretical predictions about the structure of these defects and identify new features in the electron energy-loss spectra of B atoms using high resolution chemical maps, highlighting differences between these areas and pristine sample regions. We correlate our experimental data with calculations which help explain our observations. PMID:25763963

  5. Determination of boron in graphite, boron carbide and glass by ICP-MS, ICP-OES and conventional wet chemical methods

    International Nuclear Information System (INIS)

    Boron is an important element of interest in nuclear reactor materials due to its high neutron absorption cross section (σ0 =3837 barns for 10B). In the present paper, R and D work and routinely used methods have been described for the analysis of case samples (1) Graphite where boron is present at trace levels, (2) Boron Carbide having boron concentration of about 80% and (3) Glass containing 4-6 % boron. (author)

  6. [Effectiveness of pinaverium bromide therapy on colonic motility disorders in irritable bowel syndrome].

    Science.gov (United States)

    Wittmann, T; Fehér, A; Rosztóczy, A; Jánosi, J

    1999-02-28

    The special patterns of the slow wave activity in irrittable bowel syndrome by means of surface electromyography were examined and the effect of pinaverium bromide on the symptoms and on the colonic motility in this disease was estimated. Twenty two patients with irritable bowel syndrome and 7 healthy controls were selected to the study. The clinical symptoms were abdominal pain and bloating in all patients, constipation in 9, and diarrhoea in 6 cases. Surface electromyography was carried out before and on the 14th day of the treatment with pinaverium bromide (50 mg t. i. d). The colonic motility was analysed in a 2 hour fasting and a 2 hour postprandial period following a standard (800 kCal) meal. The slow wave frequency of 0.01-0.04 Hz were selected and analysed. The mean frequency of activity peaks (n/10 min) and power-index (area under curve, microV 10 min) were measured. For statistical analysis Student's t-test was applied. Electromyogram of patients with irritable bowel syndrome showed a significant increase of the measured colonic motility parameters both in fasting and postprandial states. Fourteen days of pinaverium bromide treatment was able to significantly reduce the intensity of the colonic motor activity. Administration of pinaverium bromide completely released in 6 and significantly improved the abdominal pain in other 12 patients, while the bloating disappeared in 12 and was significantly improved in 5 from 22 patients. Pinaverium bromide was able to normalise the stool frequency: the weekly number of stools was decreased from 16 to 7 in the patients complaining diarrhoea ant it was increased from 2 to 6 in the patients with constipation. PMID:10204402

  7. Cosmis Lithium-Beryllium-Boron Story

    Science.gov (United States)

    Vangioni-Flam, E.; Cassé, M.

    Light element nucleosynthesis is an important chapter of nuclear astrophysics. Specifically, the rare and fragile light nuclei Lithium, Beryllium and Boron (LiBeB) are not generated in the normal course of stellar nucleosynthesis (except Lithium-7) and are, in fact, destroyed in stellar interiors. This characteristic is reflected in the low abundance of these simple species. Up to recently, the most plausible interpretation was that galactic cosmic rays (GCR) interact with interstellar CNO to form LiBeB. Other origins have been also identified, primordial and stellar (Lithium-7) and supernova neutrino spallation (Lithium-7 and Boron-11). In contrast, Beryllium-9, Boron-10 and Lithium-6 are pure spallative products. This last isotope presents a special interest since the Lithium-7/Lithium-6 ratio has been measured in a few halo stars offering a new constraint on the early galactic evolution. However, in the nineties, new observations prompted astrophysicists to reassess the question. Optical measurements of the beryllium and boron abundances in halo stars have been achieved by the 10 meters KECK telescope and the Hubble Space Telescope. These observations indicate a quasi linear correlation between Be and B vs Fe, at least at low metallicity, unexpected on the basis of GCR scenario, predicting a quadratic relationship. As a consequence, the origin and the evolution of the LiBeB nuclei has been revisited. This linearity implies the acceleration of C and O nuclei freshly synthesized and their fragmentation on the the interstellar Hydrogen and Helium. Wolf-Rayet stars and supernovae via the shock waves induced, are the best candidates to the acceleration of their own material enriched into C and O; so LiBeB is produced independently of the Interstellar Medium chemical composition. Moreover, neutrinos emitted by the newly born neutron stars interacting with the C layer of the supernova could produce specifically Lithium-7 and Boron-11. This process is supported by the

  8. Synovectomy by neutron capture in boron

    International Nuclear Information System (INIS)

    The rheumatoid arthritis is an illness which affect approximately at 3% of the World population. This illness is characterized by the inflammation of the joints which reduces the quality of life and the productivity of the patients. Since, it is an autoimmune illness, the inflammation is due to the overproduction of synovial liquid by the increase in the quantity of synoviocytes. The rheumatoid arthritis does not have a definitive recovery and the patients have three options of treatment: the use of drugs, the surgery and the radio synovectomy. The synovectomy by neutron capture in Boron is a novel proposal of treatment of the rheumatoid arthritis that consists in using a charged compound with Boron 10 that is preferently incorporated in the synoviocytes and to a less extent in the rest of surrounding tissues of the joint. Then, the joint is exposed to a thermal neutron field that induces the reaction (n, α) in the 10 B. the products of this reaction place their energy inside synoviocytes producing their reduction and therefore the reduction of the joint inflammation. Since it is a novel procedure, the synovectomy by neutron capture in boron has two problems: the source design and the design of the adequate drug. In this work it has been realized a Monte Carlo study with the purpose to design a moderating medium that with a 239 Pu Be source in its center, produces a thermal neutron field. With the produced neutron spectra, the neutrons spectra and neutron doses were calculated in different sites inside a model of knee joint. In Monte Carlo studies it is necessary to know the elemental composition of all the joint components, for the case of synovia and the synovial liquid this information does not exist in such way that it is supposed that its composition is equal than the water. In this work also it has been calculated the kerma factors by neutrons of synovia and the synovial liquid supposing that their elemental composition are similar to the blood tissue

  9. Implementation of Low Boron Core for APR1400 Initial Cycle

    International Nuclear Information System (INIS)

    Low boron capability of a nuclear power plant is rather a qualitative specification requiring the nuclear power plant to be shut down by control rods alone at any time of a plant cycle according to EUR. The reduction of soluble boron is beneficial since it gives the reduction of the corrosive effects in the plant system and improves plant safety giving more negative MTC. Thus, it is necessary to reduce the amount of soluble boron for the criticality to achieve the low boron capability. However, the reduction of soluble boron has its own set of specific challenges that must be overcome. There are two methods to enable the reduction of soluble boron without modifying plant system significantly. The goal of this study is to investigate the loading pattern to achieve the soluble boron reduction for Shin-Kori Unit 5 APR1400 initial core using the low and high content gadolinia burnable absorbers with standard fuel rod enrichment and to verify the feasibility of low boron core with conventional gadolinia burnable absorbers only. For this study, KARMA has been employed to solve 2-D Transport equation, and ASTRA is used for full core analysis. It was possible to achieve the low boron core for APR1400 Cycle 1 using extended usage of two types of gadolinia burnable absorbers sacrificing fuel cycle economy a little bit while enhancing plant safety significantly. Gd rod patterns within an assembly were optimized through geometrical weighting and loading pattern was developed based on these patterns. The amount of soluble boron reduction achieved is 45.4%. The improvement in plant safety is significant resulting in the reduction of least negative best-estimate MTC by about 4 pcm. Also shutdown margin is increased slightly for low boron core. However, the behavior of axial power shape turns out to be undesirable showing a relatively large fluctuation caused by the more negative MTC. It was found that the low boron core might impose kind of operational difficulty. It is usually

  10. Boron Removal in Radioactive Liquid Waste by Forward Osmosis Membrane

    International Nuclear Information System (INIS)

    These wastes contain about 0.3-0.8 wt% boric acid and have been concentrated through an evaporation treatment. Boric acid tends to crystallize owing to its solubility, and to plug the evaporator. The volume reduction obtained through evaporation is limited by the amount of boric acid in the waste. As an emerging technology, forward osmosis (FO) has attracted growing interest in wastewater treatment and desalination. FO is a membrane process in which water flows across a semi-permeable membrane from a feed solution of lower osmotic pressure to a draw solution of higher osmotic pressure. However, very few studies on the removal of boron by FO have been performed. The objective of this study is to evaluate the possibility of boron separation in radioactive liquid waste by FO. In this study, the performance of FO was investigated to separate boron in the simulated liquid waste under the factors such as pH, osmotic pressure, ionic strength of the solution, and membrane characteristic. The boron separation in radioactive borate liquid waste was investigated with an FO membrane. When the feed solution containing boron is treated by the FO membrane, the boron permeation depends on the type of membrane, membrane orientation, pH of the feed solution, salt and boron concentration in the feed solution, and osmotic pressure of the draw solution. The boron flux begins to decline from pH 7, and increases with an increase in the osmotic driving force. The boron flux of the CTA-ES and ALFD membrane orientation is higher than those of the CTA-NW and ALFF orientation, respectively. The boron permeation rate is constant regardless of the osmotic pressure and membrane orientation. The boron flux decreases slightly with the salt concentration, but it is not heavily influenced at a low salt concentration

  11. Boron Removal in Radioactive Liquid Waste by Forward Osmosis Membrane

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Dooseong; Choi, Hei Min; Lee, Kune Woo; Moon Jeikwon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    These wastes contain about 0.3-0.8 wt% boric acid and have been concentrated through an evaporation treatment. Boric acid tends to crystallize owing to its solubility, and to plug the evaporator. The volume reduction obtained through evaporation is limited by the amount of boric acid in the waste. As an emerging technology, forward osmosis (FO) has attracted growing interest in wastewater treatment and desalination. FO is a membrane process in which water flows across a semi-permeable membrane from a feed solution of lower osmotic pressure to a draw solution of higher osmotic pressure. However, very few studies on the removal of boron by FO have been performed. The objective of this study is to evaluate the possibility of boron separation in radioactive liquid waste by FO. In this study, the performance of FO was investigated to separate boron in the simulated liquid waste under the factors such as pH, osmotic pressure, ionic strength of the solution, and membrane characteristic. The boron separation in radioactive borate liquid waste was investigated with an FO membrane. When the feed solution containing boron is treated by the FO membrane, the boron permeation depends on the type of membrane, membrane orientation, pH of the feed solution, salt and boron concentration in the feed solution, and osmotic pressure of the draw solution. The boron flux begins to decline from pH 7, and increases with an increase in the osmotic driving force. The boron flux of the CTA-ES and ALFD membrane orientation is higher than those of the CTA-NW and ALFF orientation, respectively. The boron permeation rate is constant regardless of the osmotic pressure and membrane orientation. The boron flux decreases slightly with the salt concentration, but it is not heavily influenced at a low salt concentration.

  12. Boron isotope fractionation during brucite deposition from artificial seawater

    Directory of Open Access Journals (Sweden)

    J. Xiao

    2011-03-01

    Full Text Available Experiments involving boron incorporation into brucite (Mg(OH2 from magnesium-free artificial seawater with pH values ranging from 9.5 to 13.0 were carried out to better understand the incorporation behavior of boron into brucite. The results show that both concentration of boron in deposited brucite ([B]d and its boron partition coefficient (Kd between deposited brucite and final seawater are controlled by pH of the solution. The incorporation capacity of boron into brucite is much stronger than that into oxides and clay minerals. The isotopic compositions of boron in deposited brucite (δ11Bd are higher than those in the associated artificial seawater (δ11Bisw with fractionation factors ranging between 1.0177 and 1.0569, resulting from the preferential incorporation of B(OH3 into brucite. Both boron adsorptions onto brucite and precipitation reaction of H3BO3 with brucite exist during deposition of brucite from artificial seawater. The simultaneous occurrence of both processes determines the boron concentration and isotopic fractionation of brucite. The isotopic fractionation behaviors and mechanisms of boron incorporated into brucite are different from those into carbonates. Furthermore, the isotopic compositions of boron in modern corals might be affected by the existence of brucite in madrepore and the preferential incorporation of B(OH3 into brucite. An exploratory study for the influence of brucite on the boron isotopic composition in modern corals is justifiable.

  13. Influence of Boron on transformation behavior during continuous cooling of low alloyed steels

    Energy Technology Data Exchange (ETDEWEB)

    Terzic, A., E-mail: Adnan.Terzic@imf.tu-freiberg.de [Technische Universität Bergakademie Freiberg, Institute of Metal Forming, Bernhard-von-Cotta-Str. 4, 09596 Freiberg (Germany); Calcagnotto, M. [Salzgitter Mannesmann Forschung GmbH, Eisenhüttenstr. 99, 38239 Salzgitter (Germany); Guk, S. [Technische Universität Bergakademie Freiberg, Institute of Metal Forming, Bernhard-von-Cotta-Str. 4, 09596 Freiberg (Germany); Schulz, T. [Salzgitter Mannesmann Forschung GmbH, Eisenhüttenstr. 99, 38239 Salzgitter (Germany); Kawalla, R. [Technische Universität Bergakademie Freiberg, Institute of Metal Forming, Bernhard-von-Cotta-Str. 4, 09596 Freiberg (Germany)

    2013-11-01

    Abstracts: The phase transformation behavior during continuous cooling of low-carbon (LC) Boron-treated steels was studied. Furthermore, the influence of combining Boron with Nb or Ti or V on transformation kinetics was investigated. Additions of Boron to LC steels have a strong influence on the ferrite transformation. By adding 30 ppm Boron to a Boron-free reference alloy the suppressing effect on the ferrite transformation is most pronounced, whereas 10 ppm Boron has almost no effect and 50 ppm Boron the same effect as 30 ppm Boron. Thereby the critical Boron concentration for transformation kinetics in this alloying concept is 30 ppm. The combination of Boron with Ti shifts the phase fields to shorter times and increase the ferrite start temperature, whereas the combination of B+V and B+Nb only affects the ferrite start temperature. Hardness values are mostly influenced by the presence of Boron and strongly depend on the cooling rate.

  14. Determination of bromine contents in blood and hair of workers exposed to methyl by radioactivation analysis method bromide

    International Nuclear Information System (INIS)

    The bromine contained in blood and hair samples obtained from workers exposed to methyl bromide was analyzed by nondestructive activation analysis. The samples were irradiated for 1 min in pneumatic irradiation facility of Kyoto University research reactor with an estimated thermal neutron flux density at 2 x 1013 n.cm-2.sec-1. The irradiation was counted with Ge(Li) detector. The duration of measurement of radionuclide bromine in blood and hair was 200 sec within 2 - 10 min after irradiation. The bromine content of serum sample obtained from a worker suspected of methyl bromide poisoning was found to be 412 μg/g on 13 days apart from exposure to methyl bromide. The biological half-life of bromine in this case was found to be about 16 days. Then bromine contents in serum and hair samples obtained from workers exposed to methyl bromide were found to be 1.7 and 2.6 times higher respectively than those of nonexposed workers. Any correlations of bromine contents were not observed between serum and hair samples obtained from workers exposed to methyl bromide, nor between bromine amount in the serum of workers exposed to methyl bromide and the terms exposed to it, but statistically significant positive correlation was observed between bromine amount in the hair of workers exposed to methyl bromide and the terms exposed to it. (author)

  15. BORON NITRIDE CAPACITORS FOR ADVANCED POWER ELECTRONIC DEVICES

    Energy Technology Data Exchange (ETDEWEB)

    N. Badi; D. Starikov; C. Boney; A. Bensaoula; D. Johnstone

    2010-11-01

    This project fabricates long-life boron nitride/boron oxynitride thin film -based capacitors for advanced SiC power electronics with a broad operating temperature range using a physical vapor deposition (PVD) technique. The use of vapor deposition provides for precise control and quality material formation.

  16. The investigation of parameters affecting boron removal by electrocoagulation method

    International Nuclear Information System (INIS)

    Boron removal from wastewaters by electrocoagulation using aluminum electrode material was investigated in this paper. Several working parameters, such as pH, current density, boron concentration and type and concentration of supporting electrolyte were studied in an attempt to achieve a higher removal capacity. The experiments were carried out by keeping the pH of solution constant and optimum pH of solution was determined 8.0 for the aluminum electrode. Although energy consumption increased with decreasing boron concentration, which conductivity of these solutions were low, boron removal efficiency was higher at 100 mg/L than that of 1000 mg/L. Current density was an important parameter affecting removal efficiency. Boron removal efficiency and energy consumption increased with increasing current density from 1.2 to 6.0 mA/cm2. The types of different supporting electrolyte were experimented in order to investigate to this parameter effect on boron removal. The highest boron removal efficiency, 97%, was found by CaCl2. Added CaCl2 increased more the conductivity of solution according to other supporting electrolytes, but decreased energy consumption. The results showed to have a high effectiveness of the electrocoagulation method in removing boron from aqueous solutions

  17. Determination of boron in silicates after ion exchange separation

    Science.gov (United States)

    Kramer, H.

    1955-01-01

    Existing methods for the determination of boron in silicates are not entirely satisfactory. Separation as the methyl ester is lengthy and frequently erratic. An accurate and rapid method applicable to glass, mineral, ore, and water samples uses ion exchange to remove interfering cations, and boron is determined titrimetrically in the presence of mannitol, using a pH meter to indicate the end point.

  18. Low-dimensional boron structures based on icosahedron B12

    Science.gov (United States)

    Kah, C. B.; Yu, M.; Tandy, P.; Jayanthi, C. S.; Wu, S. Y.

    2015-10-01

    One-dimensional icosahedral boron chains and two-dimensional icosahedral boron sheets (icosahedral α, δ6, and δ4 sheets) that contain icosahedra B12 as their building units have been predicted in a computer simulation study using a state-of-the-art semi-empirical Hamiltonian. These novel low-dimensional icosahedral structures exhibit interesting bonding and electronic properties. Specifically, the three-center, two-electron bonding between icosahedra B12 of the boron bulk (rhombohedral boron) transforms into a two-center bonding in these new allotropes of boron sheets. In contrast to the previously reported stable buckled α and triangular boron monolayer sheets, these new allotropes of boron sheets form a planar network. Calculations of electronic density of states (DOS) reveal a semiconducting nature for both the icosahedral chain and the icosahedral δ6 and δ4 sheets, as well as a nearly gapless (or metallic-like) feature in the DOS for the icosahedral α sheet. The results for the energy barrier per atom between the icosahedral δ6 and α sheets (0.17 eV), the icosahedral δ6 and δ4 sheets (0.38 eV), and the icosahedral α and δ4 sheets (0.27 eV), as indicated in the respective parentheses, suggest that these new allotropes of boron sheets are relatively stable.

  19. Adsorption characteristics of arsenic and boron by soil

    Energy Technology Data Exchange (ETDEWEB)

    Sakata, M.

    1986-01-01

    In order to obtain baseline data concerning the surface and ground water pollution caused by coal ash disposal, adsorption characteristics of arsenic (III) and boron by soil have been studied through laboratory experiments. The main results are as follows: (1) Arsenic (III) and boron adsorption on soil was strongly dependent on pH with adsorption maxima at pH 8 and 8-9, respectively. (2) Arsenic (III) and boron adsorption on soil over the entire concentration ranges investigated could be described by the Langmuir adsorption isotherm and the Freundlich adsorption isotherm, respectively. The Henry adsorption isotherm was also applicable over the lower concentration ranges of arsenic (III) and boron (As (III): < 0.1 deltag/ml; B: < 5deltag/ml.) (3) Arsenic (III) and boron adsorption on soil is controlled mainly by the contents of extractable Fe oxide and hydroxide for arsenic (III) and by the contents of extractable Al hydroxide and allophane (amorphous aluminium silicates) for boron. (4) Adsorption and movement of arsenic (III) and boron during the infiltration of coal ash leachate in soil layer were investigated by means of the unsteady-state, one-dimensional convective-diffusive mass transport model. This model is very useful for evaluation and prediction of the contamination of ground water by trace elements such as arsenic (III) and boron leached at coal ash disposal site.

  20. Design, Fabrication and Performance of Boron-Carbide Control Elements

    International Nuclear Information System (INIS)

    A control blade design, incorporating boron-carbide (B4C) in stainless-steel tubes, was introduced into service in boiling water reactors in April 1961. Since that time this blade has become the standard reference control element in General Electric boiling-water reactors, replacing the 2% boron-stainless-steel blades previously used. The blades consist of a sheathed, cruciform array of small vertical stainless-steel tubes filled with compácted boron-carbide powder. The boron-carbide powder is confined longitudinally into several independent compartments by swaging over ball bearings located inside the tubes. The development and use of boron-carbide control rods is discussed in five phases: 1. Summary of experience with boron-steel blades and reasons for transition to boron-carbide control; 2. Design of the boron-carbide blade, beginning with developmental experiments, including early measurements performed in the AEC ''Control Rod Material and Development Program'' at the Vallecitos Atomic Laboratory, through a description of the final control blade configuration; 3. Fabrication of the blades and quality control procedures; 4. Results of confirmatory pre-operational mechanical and reactivity testing; and 5. Post-operational experience with the blades, including information on the results of mechanical inspection and reactivity testing after two years of reactor service. (author)

  1. The investigation of parameters affecting boron removal by electrocoagulation method

    Energy Technology Data Exchange (ETDEWEB)

    Yilmaz, A. Erdem [Department of Environmental Engineering, Atatuerk University, Faculty of Engineering, Erzurum (Turkey)]. E-mail: aerdemy@atauni.edu.tr; Boncukcuoglu, Recep [Department of Environmental Engineering, Atatuerk University, Faculty of Engineering, Erzurum (Turkey); Kocakerim, M. Muhtar [Department of Chemical Engineering, 25240, Atatuerk University, Faculty of Engineering Erzurum (Turkey); Keskinler, Buelent [Department of Environmental Engineering, Gebze Institute of Technology, Gebze/Kocaeli 41400 (Turkey)

    2005-10-17

    Boron removal from wastewaters by electrocoagulation using aluminum electrode material was investigated in this paper. Several working parameters, such as pH, current density, boron concentration and type and concentration of supporting electrolyte were studied in an attempt to achieve a higher removal capacity. The experiments were carried out by keeping the pH of solution constant and optimum pH of solution was determined 8.0 for the aluminum electrode. Although energy consumption increased with decreasing boron concentration, which conductivity of these solutions were low, boron removal efficiency was higher at 100 mg/L than that of 1000 mg/L. Current density was an important parameter affecting removal efficiency. Boron removal efficiency and energy consumption increased with increasing current density from 1.2 to 6.0 mA/cm{sup 2}. The types of different supporting electrolyte were experimented in order to investigate to this parameter effect on boron removal. The highest boron removal efficiency, 97%, was found by CaCl{sub 2}. Added CaCl{sub 2} increased more the conductivity of solution according to other supporting electrolytes, but decreased energy consumption. The results showed to have a high effectiveness of the electrocoagulation method in removing boron from aqueous solutions.

  2. Finite Element Analysis Of Boron Diffusion In Wood

    DEFF Research Database (Denmark)

    Krabbenhøft, Kristian; Hoffmeyer, Preben; Bechgaard, Carl; Damkilde, Lars

    The coupled heat and mass transfer equations for air, water and heat transfer are supplemented with a conservation equation for an additional species representing the concentration of boron in wood. Boundary conditions for wood-air. wood-soil and wood-boron interfaces arc discussed and finally th...

  3. Brazed boron-silicon carbide/aluminum structural panels

    Science.gov (United States)

    Arnold, W. E., Jr.; Bales, T. T.; Brooks, T. G.; Lawson, A. G.; Mitchell, P. D.; Royster, D. M.; Wiant, R.

    1978-01-01

    Fluxless brazing process minimizes degradation of mechanical properties composite material of silicon carbide coated boron fibers in an aluminum matrix. Process is being used to fabricate full-scale Boron-Silicon Carbide/Aluminum-Titanium honeycomb core panels for flight testing and ground testing.

  4. Highly thermal conductive carbon fiber/boron carbide composite material

    International Nuclear Information System (INIS)

    In a composite member for use in walls of a thermonuclear reactor, if carbon fibers and boron carbide are mixed, since they are brought into contact with each other directly, boron is reacted with the carbon fibers to form boron carbide to lower thermal conductivity of the carbon fibers. Then, in the present invention, graphite or amorphous carbon is filled between the carbon fibers to provide a fiber bundle of not less than 500 carbon fibers. Further, the surface of the fiber bundle is coated with graphite or amorphous carbon to suppress diffusion or solid solubilization of boron to carbon fibers or reaction of them. Then, lowering of thermal conductivity of the carbon fibers is prevented, as well as the mixing amount of the carbon fiber bundles with boron carbide, a sintering temperature and orientation of carbon fiber bundles are optimized to provide a highly thermal conductive carbon fiber/boron carbide composite material. In addition, carbide or boride type short fibers, spherical graphite, and amorphous carbon are mixed in the boron carbide to prevent development of cracks. Diffusion or solid solubilization of boron to carbon fibers is reduced or reaction of them if the carbon fibers are bundled. (N.H.)

  5. Does boron affect hormone levels of barley cultivars?

    Directory of Open Access Journals (Sweden)

    Muavviz Ayvaz

    2012-11-01

    Full Text Available Background: When mineral nutrients are present in excess or in inadequate amounts, their effects can be severe in plants and can be considered as abiotic stress. In this study, we report how hormonal levels in barley cultivars respond to the toxic effect of boron, an essential plant micronutrient. Material and methods: Two different barley (Hordeum vulgare cultivars (Vamik Hoca and Efes 98 were used as a study material. Boron was applied in three different concentrations (0, 10, 20 ppm to plants that had grown from seeds for four weeks. Plants were harvested, stem-root length and stem-root dry-fresh weight content were determined. For further analysis, chlorophyll, total protein, endogenic IAA and ABA content analyses were carried out. Results: According to the data obtained, plant growth and development decreased with increasing boron concentrations. With increasing boron concentrations, soluble total protein increased in both cultivars. Boron application led to increased endogenic IAA content in both cultivars. 10 and 20 ppm boron application led to increased endogenic ABA content in Vamik Hoca cultivar whereas endogenic ABA content decreased in Efes 98. Absence of boron application led to increased endogenic IAA and ABA content in both cultivars. Conclusion: As a result, the response to boron is different in the two cultivars and Efes 98 may be more resistant to the toxicity than Vamik Hoca cultivar.

  6. Composition and microhardness of CAE boron nitride films

    International Nuclear Information System (INIS)

    The paper deals with boron nitride produced by cathodic arc evaporation techniques.The films were applied on titanium and cemented carbide substrates. Their characterization was carried out using X-ray diffraction and Knoop microhardness tests. Demonstrated are the high properties of two-phase films, containing β (cubic) and γ (wurtzitic) modifications of boron nitride. (author). 7 refs., 1 fig., 3 tabs

  7. Boron compounds as potential HIV-1 protease inhibitors

    Czech Academy of Sciences Publication Activity Database

    Plešek, Jaromír; Grüner, Bohumír; Král, V.; Cígler, Petr; Kožíšek, Milan; Prejdová, Jana; Pokorná, Jana; Kräusslich, H. G.; Bodem, J.; Konvalinka, Jan

    Tohoku: Graduate School of Science, 2005, s. 46. [International Conference on Boron Chemistry /12./. Sendai (JP), 11.09.2005-15.09.2005] R&D Projects: GA MŠk(CZ) LC523 Institutional research plan: CEZ:AV0Z40320502 Keywords : boron cluster compounds Subject RIV: CA - Inorganic Chemistry

  8. Eleventh international conference on boron chemistry. Programme and abstracts

    International Nuclear Information System (INIS)

    Abstracts of reports at the Eleventh International Conference on Boron Chemistry are presented. Born chemistry as a connecting bridge between many fields maintains one of the leading positions in modern chemistry. Methods of synthesis of different boron compounds, properties of the compounds, their use in other regions of chemistry and medicine are widely presented in reports

  9. Boron Speciation in Soda-Lime Borosilicate Glasses Containing Zirconium

    International Nuclear Information System (INIS)

    Boron speciation was investigated in soda-lime borosilicate glass containing zirconium. In such compositions, competition between charge compensators (here, sodium and calcium) can occur for the compensation of tetrahedral boron or octahedral zirconium units. 11B MAS NMR is particularly suitable for obtaining data on preferential compensation behavior that directly affects the boron coordination number. In addition to the classical proportions of tri- and tetrahedral boron, additional data can be obtained on the contributions involved in these two coordination numbers. An approach is described here based on simultaneous MAS spectrum analysis of borosilicate glass with variable Zr/Si and Ca/Na ratios at two magnetic field strengths (11. 7 and 18. 8 T), with constraints arising from MQMAS spectroscopy, detailed analysis of satellite transitions, and spin-echo experiments. New possibilities of 11B NMR were presented for improving the identification and quantification of the different contributions involved in tri- and tetrahedral boron coordination. Both NMR and Raman revealed a trend of decreased tetrahedral boron proportion with the increase of Ca/Na ratio or the Zr/Si ratio. This strongly suggests that zirconium compensation takes preference over boron compensation, and that zirconium and boron are both compensated mainly by sodium rather than calcium. (authors)

  10. Predicted phase diagram of boron-carbon-nitrogen

    Science.gov (United States)

    Zhang, Hantao; Yao, Sanxi; Widom, Michael

    2016-04-01

    Noting the structural relationships between phases of carbon and boron carbide with phases of boron nitride and boron subnitride, we investigate their mutual solubilities using a combination of first-principles total energies supplemented with statistical mechanics to address finite temperatures. Thus we predict the solid-state phase diagram of boron-carbon-nitrogen (B-C-N). Owing to the large energy costs of substitution, we find that the mutual solubilities of the ultrahard materials diamond and cubic boron nitride are negligible, and the same for the quasi-two-dimensional materials graphite and hexagonal boron nitride. In contrast, we find a continuous range of solubility connecting boron carbide to boron subnitride at elevated temperatures. An electron-precise ternary compound B13CN consisting of B12 icosahedra with NBC chains is found to be stable at all temperatures up to melting. It exhibits an order-disorder transition in the orientation of NBC chains at approximately T =500 K. We also propose that the recently discovered binary B13N2 actually has composition B12.67N2 .

  11. Safety assessment of boron in aquatic and terrestrial environments.

    Science.gov (United States)

    Butterwick, L; de Oude, N; Raymond, K

    1989-06-01

    Boron is a naturally occurring material and is used in industrial and domestic products. Its major release into the environment is through weathering processes and wastewater discharge. Boron is an essential nutrient for plants, but can above certain concentrations be toxic to aquatic and terrestrial organisms. This paper assesses the ecotoxicology and environmental safety of boron. It draws together the data for toxicological effects of boron and compares these with environmental concentrations of boron, measured in Europe and the U.S.A. Generally, environmental concentrations of boron found in surface water are below levels identified as toxic to aquatic organisms. Concentrations high enough to produce toxic effects in laboratory tests are found in areas where weathering of boron-rich formations and deposits occurs, such as in the southwestern United States. However, reproducing populations of the most sensitive species, rainbow trout, have been observed in surface waters in these regions, indicating no cause for concern. The prime concern for effects on terrestrial plants centers on the use of irrigation water with elevated levels of boron. At present, there is no evidence of widespread damage to crops resulting from this practice. In some areas, wastewater is used for irrigation and crops grown under these conditions are generally confined to those relatively insensitive to boron toxicity. Good irrigation practices will be necessary, however, in arid regions with high evapotranspiration rates and care will be needed when using wastewater, particularly in areas with naturally high boron levels. It is not anticipated that there will be any significant increase in the discharge of boron to the environment in the foreseeable future. The use of boron-containing products is expected to increase, but glass will remain the dominant market and the use of boron in detergents in Europe is expected to decrease due to the introduction of bleach activators and liquid

  12. Comparative microvascular exchange kinetics of [{sup 77}Br]bromide and {sup 99m}Tc-DTPA in humans

    Energy Technology Data Exchange (ETDEWEB)

    Cousins, Claire [Department of Clinical Radiology, Addenbrooke' s Hospital, Cambridge (United Kingdom); Skehan, Stephen J.; Rolph, Susan M.; Flaxman, Mary E.; Ballinger, James R.; Bird, Nicholas J.; Barber, Robert W.; Peters, Michael A. [Department of Nuclear Medicine, Addenbrooke' s Hospital, Cambridge (United Kingdom)

    2002-05-01

    The plasma clearance curves of small hydrophilic solutes comprise three exponentials, consistent with a three-compartmental distribution model. A previous comparison between inulin and diethylene triamine penta-acetic acid (DTPA) suggested that these three compartments are in series, the first being plasma and the second and third representing compartments within the extravascular space. Moreover, whilst the total distribution volumes of these two indicators were similar, the volume of the second compartment was higher for DTPA. The purpose of the current study was to investigate whether a solute smaller than DTPA, namely bromide, fits the hypothesis that the second space volume is an inverse function of the size of the solute. Two groups of subjects were studied: group A comprised eight patients undergoing routine diagnostic arteriography and group B, eight patients referred for routine measurement of glomerular filtration rate plus two normal volunteers. {sup 99m}Tc-DTPA and sodium [{sup 77}Br]bromide were intravenously administered simultaneously. In group A, frequent arterial samples were obtained up to 40 min after injection, and antecubital venous samples 30 s after each arterial sample. In group B, frequent venous samples were obtained up to 280 min after injection. Volume measurements based on bromide were corrected for erythrocyte bromide accumulation. In both subject groups, the normalised venous concentration ratio of bromide to DTPA, corrected for red cell bromide uptake, was significantly less than unity in the earliest blood samples, being 0.56 (SD 0.08) at 1 min, consistent with faster diffusion of bromide from plasma to interstitial fluid. Furthermore, the extraction fraction of bromide from plasma to interstitial fluid in the forearm was about 0.6, higher than that of DTPA (about 0.5) in spite of red cell bromide accumulation which equilibrated with plasma bromide within 20 s and resulted in a red cell to plasma concentration ratio of 0.51 (0

  13. Cobalt-Catalyzed Cross-Coupling of Grignards with Allylic and Vinylic Bromides: Use of Sarcosine as a Natural Ligand.

    Science.gov (United States)

    Frlan, Rok; Sova, Matej; Gobec, Stanislav; Stavber, Gaj; Časar, Zdenko

    2015-08-01

    Sarcosine was discovered to be an excellent ligand for cobalt-catalyzed carbon-carbon cross-coupling of Grignard reagents with allylic and vinylic bromides. The Co(II)/sarcosine catalytic system is shown to perform efficiently when phenyl and benzyl Grignards are coupled with alkenyl bromides. Notably, previously unachievable Co-catalyzed coupling of allylic bromides with Grignards to linearly coupled α-products was also realized with Co(II)/sarcosine catalyst. This method was used for efficient preparation of the key intermediate in an alternative synthesis of the antihyperglycemic drug sitagliptin. PMID:26158563

  14. Depletion modeling of integral burnable absorbers containing enriched boron

    International Nuclear Information System (INIS)

    Depletion modeling of fuel assembly with different integral fuel burnable absorber loadings containing enriched boron has been performed by WIMSD transport code. Equivalent boron concentration that represents depletion of the integral fuel burnable absorbers containing enriched boron has been calculated using modified PSU/LEOPARD code. The calculated equivalent boron concentrations have been introduced into FUMACS computer code package master files, upgrading the code package with new global calculation feature for core modeling with different integral fuel burnable absorber loadings containing enriched boron. This new feature of FUMACS/FEEC2001 code package has been verified and validated on 12-month and 18-month operating cycle core loading patterns of NPP Krsko.(author)

  15. The sorption capacity of boron on anionic-exchange resin

    International Nuclear Information System (INIS)

    Boron sorption capacities on anionic-exchange resins vary with temperature, concentration, and resin cross-linkage. A semiempirical correlation, developed from boron solution chemistry, is presented to account for these variations. The relationship, based on boron chemistry and changes in Gibb's energy, can be stated approximately as Q = a1CBa2Za3 exp[-(a4T + a5T2 + a6Z0.5)]. Correlation parameters, which vary with resin type, are evaluated experimentally. Parameter values for macroporous resin Diaion PA 300 and for gel-type resins Diaion SA10 and Amberlite IRN 78LC are presented. The resulting expression is used to determine boron sorption and desorption limitations on ion exchangers at various temperatures and concentrations, and to determine the interfacial boron concentration in equilibrium and rate models

  16. Investigation of boron segregation in low carbon steel

    Directory of Open Access Journals (Sweden)

    J. Lis

    2011-04-01

    Full Text Available Traces of born in the range 0,002-0,009 % are usually added to many grades of steel. The effect of boron on phase transformations and hardenability of low carbon low alloy steels depends on the form of its behavior in solid solution either in segregations or in precipitations. Temperature and cooling rate determine the existence of boron segregations on grain boundaries. In present paper simulations of boron concentrations were calculated with computer programme DICTRA for low carbon 0,08 %C steel with 0,006 % boron. Investigations were carried out for temperature 1300 – 700°C and cooling rates from 1°C/s to 100°C/s. The changes of boron concentrations in austenite and ferrite after commencement of γ→α phase transformation were established.

  17. Boronization during the first plasma operation on EAST

    International Nuclear Information System (INIS)

    Both ion cyclotron rf and glow discharge boronization have been successfully used for wall conditioning on EAST tokamak device. The whole process is monitored continuously by residual gas analyzer and film thickness monitor. These diagnostics provide detailed information about the boronization. High hydrogen inventory level observed after boronization maybe due to the boronization material used (C2B10H12). Ion cyclontron rf conditioning is proved to be an efficient wall conditioning method for superconducting device because it could be carried out under toroidal magnetic field. In this paper, the procedure of boronization is described, and subsequently sample analysis and the effect on plasma operation are introduced. Conclusion is given at the end

  18. Steam oxidation of boron carbide–stainless steel liquid mixtures

    International Nuclear Information System (INIS)

    In the framework of nuclear reactor core meltdown accidents studies, the oxidation kinetics of boron carbide–stainless steel liquid mixtures exposed to argon/steam atmospheres was investigated at temperatures up to 1527 °C. A B–Cr–Si–O liquid protective layer forms on the surface of the mixtures in contact with steam. This protective layer gradually transforms into a Cr2O3-rich slag. Important quantities of liquid can be projected from the melt during oxidation. These projections are favoured by high B4C contents in the melt, high steam partial pressures and low temperatures. In addition to stainless steel–boron carbide melts, simpler compositions (pure 304L stainless steel, iron–boron, iron–boron carbide and stainless steel–boron) were studied, in order to identify the basic oxidation mechanisms.

  19. Synthesis and photoluminescence property of boron carbide nanowires

    International Nuclear Information System (INIS)

    Large scale, high density boron carbide nanowires have been synthesized by using an improved carbothermal reduction method with B/B2O3/C powder precursors under an argon flow at 1100°C. The boron carbide nanowires are 5–10 μm in length and 80–100 nm in diameter. Transmission electron microscopy (TEM) and selected area electron diffraction (SAED) characterizations show that the boron carbide nanowire has a B4C rhombohedral structure with good crystallization. The Raman spectrum of the as-grown boron carbide nanowires is consistent with that of a B4C structure consisting of B11C icosahedra and C-B-C chains. The room temperature photoluminescence spectrum of the boron carbide nanowires exhibits a visible range of emission centred at 638 nm. (condensed matter: structure, thermal and mechanical properties)

  20. Enhanced surface hardness by boron implantation in Nitinol alloy.

    Science.gov (United States)

    Lee, D H; Park, B; Saxena, A; Serene, T P

    1996-10-01

    Boron implantation into Nitinol alloy has a potential for developing improved Nitinol root canal instruments with excellent cutting properties, without affecting their superelastic bulk-mechanical properties. The surface hardness of nickel-titanium (NiTi) alloy, also known as "Nitinol" (50 atm% nickel+50 atm% titanium), has been improved by ion-beam surface modification. With an implantation dose of 4.8 x 10(17) boron/cm2, a high concentration of boron (30 atm%) is incorporated into NiTi alloy by 110 keV boron ions at room temperature (25 degrees C). Boron-implanted and unimplanted (pure) Nitinol alloys show surface hardness of 7.6 +/- 0.2 and 3.2 +/- 0.2 GPa, respectively, at the nanoindentation depth of 0.05 micron. The ion-beam-modified NiTi alloy exceeds the surface hardness of stainless steel. PMID:9198443

  1. Advancements in Tumor Targeting Strategies for Boron Neutron Capture Therapy.

    Science.gov (United States)

    Luderer, Micah John; de la Puente, Pilar; Azab, Abdel Kareem

    2015-09-01

    Boron neutron capture therapy (BNCT) is a promising cancer therapy modality that utilizes the nuclear capture reaction of epithermal neutrons by boron-10 resulting in a localized nuclear fission reaction and subsequent cell death. Since cellular destruction is limited to approximately the diameter of a single cell, primarily only cells in the neutron field with significant boron accumulation will be damaged. However, the emergence of BNCT as a prominent therapy has in large part been hindered by a paucity of tumor selective boron containing agents. While L-boronophenylalanine and sodium borocaptate are the most commonly investigated clinical agents, new agents are desperately needed due to their suboptimal tumor selectivity. This review will highlight the various strategies to improve tumor boron delivery including: nucleoside and carbohydrate analogs, unnatural amino acids, porphyrins, antibody-dendrimer conjugates, cationic polymers, cell-membrane penetrating peptides, liposomes and nanoparticles. PMID:26033767

  2. APPLICATION OF BORON MODIFIED SILICA SOL ON RETENTION AND DRAINAGE

    Institute of Scientific and Technical Information of China (English)

    JinxiaMa; YuxiuPeng; ZhongzhengLi

    2004-01-01

    In this paper it was studied that these dosage effectsof CPAM, cationic starch,boron modified silica sol(BMS), A12(SO4)3, pH value and electrolyte on theretention and drainage of different microparticulatesystems including CPAM, cationic starch and boronsilica sol. The research results indicated that CPAMhad no good retention when used with boron silicasol. The best retention efficiency was the micropar-ticulate system of CPAM + cationic starch withboron modified silica sol; Secondly was that ofcationic starch with boron modified silica sol; Theworst was that of CPAM with boron modified silicasol. The retention efficiency had no relation with theaddition order between CPAM and cationic starch. Itwas also found that the microparticulate retentionsystem of boron modified silica sol could be used inalum-rosin sizing and in acidity, neutral or alkalinepapermaking conditions. This system also could beused with close circulate water so that it could reducethe water pollution and waste.

  3. Optical characteristic analysis of the boronization process by using carborane

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Wonwook; Park, Kyungdeuk; Choi, Youngsun; Oh, Chahwan [Hanyang University, Seoul (Korea, Republic of)

    2014-09-15

    Boronization with carborane (C{sub 2}B{sub 10}H{sub 12}) was achieved in a vacuum vessel coupled to a filament discharge system. Optical emission spectroscopy was employed to characterize the boronization process. The Balmer lines of hydrogen and deuterium were measured, and the boronization process was analyzed by using the intensity ratio of the H{sub α} to the D{sub α} line (I{sub H}/I{sub D}). The relation between the pressure and the intensity ratio was investigated, and the thickness of the deposited boron film was predicted. Also, the dilution ratio H/(H + D) of the boron film was analyzed and compared with the one predicted from an optical analysis of the emission spectrum.

  4. Ion implantation of boron in germanium

    Energy Technology Data Exchange (ETDEWEB)

    Jones, K.S.

    1985-05-01

    Ion implantation of /sup 11/B/sup +/ into room temperature Ge samples leads to a p-type layer prior to any post implant annealing steps. Variable temperature Hall measurements and deep level transient spectroscopy experiments indicate that room temperature implantation of /sup 11/B/sup +/ into Ge results in 100% of the boron ions being electrically active as shallow acceptor, over the entire dose range (5 x 10/sup 11//cm/sup 2/ to 1 x 10/sup 14//cm/sup 2/) and energy range (25 keV to 100 keV) investigated, without any post implant annealing. The concentration of damage related acceptor centers is only 10% of the boron related, shallow acceptor center concentration for low energy implants (25 keV), but becomes dominant at high energies (100 keV) and low doses (<1 x 10/sup 12//cm/sup 2/). Three damage related hole traps are produced by ion implantation of /sup 11/B/sup +/. Two of these hole traps have also been observed in ..gamma..-irradiated Ge and may be oxygen-vacancy related defects, while the third trap may be divacancy related. All three traps anneal out at low temperatures (<300/sup 0/C). Boron, from room temperature implantation of BF/sub 2//sup +/ into Ge, is not substitutionally active prior to a post implant annealing step of 250/sup 0/C for 30 minutes. After annealing additional shallow acceptors are observed in BF/sub 2//sup +/ implanted samples which may be due to fluorine or flourine related complexes which are electrically active.

  5. Boron-nitride coated nuclear fuels

    Energy Technology Data Exchange (ETDEWEB)

    Guenduez, G. [Orta Dogu Teknik Univ., Ankara (Turkey); Uslu, I. [Tuerkiye Atom Enerjisi Kurumu, Ankara (Turkey); Durmazucar, H.H. [Cumhuriyet Univ., Sivas (Turkey)

    1996-10-01

    Pure urania- and urania-gadolinia-containing fuel pellets were coated with boron nitride (BN) to improve the physical and neutronic properties of the fuel. The BN coating seems to have a technological advantage over zirconium-diboride coating. The BN is chemically inert, corrosion resistant, withstands rapid temperature changes, and has a high thermal conductivity. Since gadolinia fuel has low thermal conductivity. Since gadolinia fuel has low thermal conductivity, the gadolinia content can be lowered in the fuel by coating it with BN. In fact, the existence of two burnable absorbers in a fuel introduces desired nuclear properties since gadolinia is a fast-burning and boron a slow-burning element. The BN was deposited on fuel from two different sources, (a) from the reaction of boron trichloride (BCl{sub 3}) and ammonia (NH{sub 3}) at 875 K and (b) from the decomposition of trimethylamine borate complex at 1200 K. The infrared and X-ray diffraction (XRD) spectra of BN from both precursors agreed with the available data in the literature. However BN powder from borane complex had a shifted XRD peak due to the presence of carbonaceous material in the structure. The BN powder-coated fuels were heated to 1400, 1525, and 1600 K to sinter the BN. The examination under scanning electron microscope showed that grainy, rod-shaped and layered BN coatings were achieved. Rod-shaped structures were usually seen on gadolinia fuels. The increased thickness of coating favors the formation of a glassy looking layer. The BN from a borane complex seems to form a layered structure more easily than the BN from BCl{sub 3}. The BN coated the surface of the fuels, and it did not penetrate into the fuels.

  6. Boron-nitride coated nuclear fuels

    International Nuclear Information System (INIS)

    Pure urania- and urania-gadolinia-containing fuel pellets were coated with boron nitride (BN) to improve the physical and neutronic properties of the fuel. The BN coating seems to have a technological advantage over zirconium-diboride coating. The BN is chemically inert, corrosion resistant, withstands rapid temperature changes, and has a high thermal conductivity. Since gadolinia fuel has low thermal conductivity. Since gadolinia fuel has low thermal conductivity, the gadolinia content can be lowered in the fuel by coating it with BN. In fact, the existence of two burnable absorbers in a fuel introduces desired nuclear properties since gadolinia is a fast-burning and boron a slow-burning element. The BN was deposited on fuel from two different sources, (a) from the reaction of boron trichloride (BCl3) and ammonia (NH3) at 875 K and (b) from the decomposition of trimethylamine borate complex at 1200 K. The infrared and X-ray diffraction (XRD) spectra of BN from both precursors agreed with the available data in the literature. However BN powder from borane complex had a shifted XRD peak due to the presence of carbonaceous material in the structure. The BN powder-coated fuels were heated to 1400, 1525, and 1600 K to sinter the BN. The examination under scanning electron microscope showed that grainy, rod-shaped and layered BN coatings were achieved. Rod-shaped structures were usually seen on gadolinia fuels. The increased thickness of coating favors the formation of a glassy looking layer. The BN from a borane complex seems to form a layered structure more easily than the BN from BCl3. The BN coated the surface of the fuels, and it did not penetrate into the fuels

  7. Ballistic thermoelectric properties in boron nitride nanoribbons

    Science.gov (United States)

    Xie, Zhong-Xiang; Tang, Li-Ming; Pan, Chang-Ning; Chen, Qiao; Chen, Ke-Qiu

    2013-10-01

    Ballistic thermoelectric properties (TPs) in boron nitride nanoribbons (BNNRs) are studied using the nonequilibrium Green's function atomistic simulation of electron and phonon transport. A comparative analysis for TPs between BNNRs and graphene nanoribbons (GNRs) is made. Results show that the TPs of BNNRs are better than those of GNRs stemming from the higher power factor and smaller thermal conductance of BNNRs. With increasing the ribbon width, the maximum value of ZT (ZTmax) of BNNRs exhibits a transformation from the monotonic decrease to nonlinear increase. We also show that the lattice defect can enhance the ZTmax of these nanoribbons strongly depending on its positions and the edge shape.

  8. Magnesium doping of boron nitride nanotubes

    Science.gov (United States)

    Legg, Robert; Jordan, Kevin

    2015-06-16

    A method to fabricate boron nitride nanotubes incorporating magnesium diboride in their structure. In a first embodiment, magnesium wire is introduced into a reaction feed bundle during a BNNT fabrication process. In a second embodiment, magnesium in powder form is mixed into a nitrogen gas flow during the BNNT fabrication process. MgB.sub.2 yarn may be used for superconducting applications and, in that capacity, has considerably less susceptibility to stress and has considerably better thermal conductivity than these conventional materials when compared to both conventional low and high temperature superconducting materials.

  9. Boron nitride nanomaterials for thermal management applications.

    Science.gov (United States)

    Meziani, Mohammed J; Song, Wei-Li; Wang, Ping; Lu, Fushen; Hou, Zhiling; Anderson, Ankoma; Maimaiti, Halidan; Sun, Ya-Ping

    2015-05-18

    Hexagonal boron nitride nanosheets (BNNs) are analogous to their two-dimensional carbon counterparts in many materials properties, in particular, ultrahigh thermal conductivity, but also offer some unique attributes, including being electrically insulating, high thermal stability, chemical and oxidation resistance, low color, and high mechanical strength. Significant recent advances in the production of BNNs, understanding of their properties, and the development of polymeric nanocomposites with BNNs for thermally conductive yet electrically insulating materials and systems are highlighted herein. Major opportunities and challenges for further studies in this rapidly advancing field are also discussed. PMID:25652360

  10. Boron Pile v-bar Measurements

    International Nuclear Information System (INIS)

    Accurate absolute measurements of v, the average number of neutrons per fission, have been made with the boron pile. The experimental method is described and results are presented of the v values obtained for the thermal-neutron-induced fission of U233, U235, Pu239 and Pu241, the spontaneous fission of Pu240 and Cf252, and the fast neutron-induced fission of U235 in the energy range 100 keV to 2.6 MeV. (author)

  11. Low-dimensional boron nitride nanomaterials

    Directory of Open Access Journals (Sweden)

    Amir Pakdel

    2012-06-01

    Full Text Available In this review, a concise research history of low-dimensional boron nitride (BN nanomaterials followed by recent developments in their synthesis, morphology, properties, and applications are presented. Seventeen years after the initial synthesis of BN nanotubes, research on BN nanomaterials has developed far enough to establish them as one of the most promising inorganic nanosystems. In this regard, it is envisaged that the unique properties of low-dimensional BN systems, such as superb mechanical stiffness, high thermal conductivity, wide optical bandgap, strong ultraviolet emission, thermal stability and chemical inertness will play a key role in prospective developments.

  12. Boron-containing neutron shielding building ceramics

    International Nuclear Information System (INIS)

    The data are presented on the composition of raw materials as well as on the properties and chemical composition of finished products of ceramics intended for neutron shielding. It is shown that 0.8 % content of B2O3 in bricks of ceramic mass proposed halves neutron radiation from the source of 106 neutr·s-1 close rate compared to bricks of boron free ceramic mass. Results of tests on water absorption and compression strength make it possible to recommend new ceramics to be used as tiles and facade building materials

  13. Salinity’s influence on boron toxicity in broccoli: II. Impacts on boron uptake, uptake mechanisms and tissue ion relations.

    Science.gov (United States)

    Limited research has been conducted on the interactive effects of salinity and boron stresses on plants despite their common occurrence in natural systems. The purpose of this research was to determine and quantify the interactive effects of salinity, salt composition and boron on broccoli (Brassica...

  14. Continued biological investigations of boron-rich oligomeric phosphate diesters (OPDs). Tumor-selective boron agents for BNCT

    International Nuclear Information System (INIS)

    Clinical success of Boron Neutron Capture Therapy will rely on the selective intracellular delivery of high concentrations of boron-10 to tumor tissue. In order for a boron agent to facilitate clinical success, the simultaneous needs of obtaining a high tumor dose, high tumor selectivity, and low systemic toxicity must be realized. Boron-rich oligomeric phosphate diesters (OPDs) are a class of highly water-soluble compounds containing up to 40% boron by weight. Previous work in our groups demonstrated that once placed in the cytoplasm of tumor cells, OPDs quickly accumulate within the cell nucleus. The objective of the current study was to determine the biodistribution of seven different free OPDs in BALB/c mice bearing EMT6 tumors. Fructose solutions containing between 1.4 and 6.4 micrograms of boron per gram of tissue were interveinously injected in mice seven to ten days after tumor implantation. At intervals during the study, animals were euthanized and samples of tumor, blood, liver, kidney, brain and skin were collected and analyzed for boron content using ICP-AES. Tumor boron concentrations of between 5 and 29 ppm were achieved and maintained over the 72-hour time course of each experiment. Several OPDs demonstrated high tumor selectivity with one oligomer exhibiting a tumor to blood ratio of 35:1. The apparent toxicity of each oligomer was assessed through animal behavior during the experiment and necropsy of each animal upon sacrifice. (author)

  15. Boron carbide particles formed from an amorphous boron/graphite powder mixture using a shock-wave technique

    International Nuclear Information System (INIS)

    Boron carbide (B4C) particles with filamental, distorted ellipsoidal, platelike, and polyhedral shapes were formed from vapor generated from an amorphous boron/graphite powder mixture with 14% starting density using a cylindrical shock-wave technique. The crystal phases of shocked compact and microstructures of the B4C particles were characterized by X-ray diffractometry and electron microscopy, respectively

  16. Thorium electrode potentials in equimolar melt of potassium and sodium bromides

    International Nuclear Information System (INIS)

    The equilibrium electrode potentials of thorium in an equimolar mixture of potassium and sodium bromides are measured for 700, 800 and 900 deg C within the concentration range from 0.3 to 3.0 molar %. Th. The bi - and tetravalent ions are found to dominate in equilibrium with the metal. Temperature dependence of the equilibrium constant of reaction Th(solid) + Th4+(melt) reversible 2 Th2+(melt) is obtained and the conventional standard thorium electrode potentials with respect to its bi - and tetravalent ions are measured. Upon replacement of chlorine aniones by bromine ones the reaction shifted to the right hand side. Experimental data enabled to estimate the thermodynamics of mixing liquid thorium tetrabromide with the melted mixture of potassium and sodium bromides

  17. Indirect complexometric determination of mercury(II) using potassium bromide as selective masking agent

    International Nuclear Information System (INIS)

    A complexometric method for the determination of mercury in presence of other metal ions based on the selective masking ability of potassium bromide towards mercury is described. Mercury(II) present in a given sample solution is first complexed with a known excess of EDTA and the surplus EDTA is titrated against zinc sulfate solution at pH 5-6 using xylenol orange as the indicator. A known excess of 10 % solution of potassium bromide is then added and the EDTA released from Hg-EDTA complex is titrated against standard zinc sulfate solution. Reproducible and accurate results are obtained for 8 mg to 250 mg of mercury(II) with a relative error ±0.28 % and standard deviations /leg 0.5 mg. The interference of various ions is studied. This method was applied to the determination of mercury(II) in its alloys. (author)

  18. Plasma fluoride and bromide concentrations during occupational exposure to enflurane or halothane

    Energy Technology Data Exchange (ETDEWEB)

    Carlsson, P.; Ekstrand, J.; Hallen, B.

    1985-10-01

    The plasma fluoride and bromide concentrations were studied in operating theatre personnel. When enflurane was used, the increase in plasma fluoride concentration could not be distinguished from normal individual variations, but the plasma bromide concentration increased significantly when halothane was used. Seven patients were exposed to enflurane in a concentration of 200 parts per million for 4 h. A significant increase in the plasma concentration of fluoride was observed. The peak concentrations of fluoride occurred during exposure and the increase lasted less than 12 h. The increase in fluoride concentration was larger at this trace concentration than reported after anesthetic concentrations. Cerebrospinal fluid (CSF) fluoride concentration was also studied; a smaller and delayed increase was found in CSF compared to plasma.

  19. Study of the corrosion resistance of metals in a lithium bromide solution

    Energy Technology Data Exchange (ETDEWEB)

    Mel' nik, V.V.; Spivak, R.Sh.; Sokolov, V.V.; Trofimenko, A.G.

    1988-07-01

    Results are reported of a study of the corrosion resistance of the stainless steels 12Kh19N10T, 10Kh17N13M3T, 08Kh17N15M3T, 10Kh21N6M2T, and 06KhI28MDT, cupronickel MNZhMts 30-1-1, nickel NP-2, and titanium alloys VT1-0, PT-1M, and PT-3V in a solution of lithium bromide for purposes of assessing these alloys for use in absorption-type refrigerating units using the bromide as an absorbent. The uniform corrosion rate was determined from the weight loss; the nonuniform corrosion rate was determined by measuring the maximum depth of the pits under a microscope. Results are comparatively evaluated.

  20. Study of the isotope effect in hydrogen exchange reactions in liquid hydrogen bromide and liquid ammonia

    International Nuclear Information System (INIS)

    The subject of the investigation was the thermodynamic isotope effects in naphthalene-hydrogen bromide and benzene-ammonia systems in the presence of potassium amide acting as a catalyst. Protium, deuterium and tritium atoms were present in the system during the experiments. In the experiments on direct and ''reverse'' exchange, the kinetic isotope effects of hydrogen were measured in the liquid-phase systems hydrogen bromide-diphenvl and benzene-ammonia. The mechanisms of exchange reactions of aromatic hydrocarbons with HBr and NH3 are considered with regard to the findings of kinetic experiments. There is a brief description of the methods of preparation in which deuterized and tritiated compounds are used. For tritium counting a scintillation coincidence system was used; and spectroscopic and mass spectrometric methods were used for the isotopic analysis of deuterized substances. (author)

  1. Apparent molal volumes of symmetrical and asymmetrical isomers of tetrabutylammonium bromide in water at several temperatures

    International Nuclear Information System (INIS)

    Highlights: • Apparent molal volumes of five isomers of Bu4NBr in water have been measured. • The structural effect of branched and linear chains is discussed. • The structural contributions to the ionic volume were calculated. -- Abstract: Apparent molal volumes of a series of differently substituted quaternary ammonium bromides, namely tetra-iso-butyl-, tetra-sec-butyl-, tetra-n-butyl-, di-n-butyl-di-sec-butyl- and di-n-butyl-di-iso-butylammonium bromide have been determined as a function of molal concentration at (298.15, 303.15 and 308.15) K. Partial molar volumes at infinite dilution and ionic molar volumes of these quaternary ammonium cations were determined. Structural volume contributions to the ionic molar volume were also calculated. The symmetric and asymmetric quaternary ammonium cations are “structure making” ions. The contribution of the branched butyl chains predominates over the linear butyl chains in the asymmetric cations

  2. Facile Synthesis of Heterocycles via 2-Picolinium Bromide and Antimicrobial Activities of the Products

    Directory of Open Access Journals (Sweden)

    Elham S. Darwish

    2008-05-01

    Full Text Available The 2-picolinium N-ylide 4, generated in situ from the N-acylmethyl-2-picolinium bromide 3, underwent cycloaddition to N-phenylmaleimide or carbon disulfideto give the corresponding cycloadducts 6 and 8, respectively similar reactions ofcompound 3 with some electron-deficient alkenes in the presence of MnO2 yielded theproducts 11 and 12. In addition, reaction of 4 with arylidene cyanothioacetamide andmalononitrile derivatives afforded the thiophene and aniline derivatives 15 and 17,respectively. Heating of picolinium bromide 3 with triethylamine in benzene furnished 2-(2-thienylindolizine (18. The structures of the isolated products were confirmed byelemental analysis as well as by 1H- and 13C-NMR, IR, and MS data. Both thestereochemistry and the regioselectivity of the studied reactions are discussed. Thebiological activity of the newly synthesized compounds was examined and showedpromising results.

  3. A novel model-based approach for dose determination of glycopyrronium bromide in COPD

    Directory of Open Access Journals (Sweden)

    Arievich Helen

    2012-12-01

    Full Text Available Abstract Background Glycopyrronium bromide (NVA237 is an inhaled long-acting muscarinic antagonist in development for treatment of COPD. This study compared the efficacy and safety of once-daily (OD and twice-daily (BID glycopyrronium bromide regimens, using a novel model-based approach, in patients with moderate-to-severe COPD. Methods Double-blind, randomized, dose-finding trial with an eight-treatment, two-period, balanced incomplete block design. Patients (smoking history ≥10 pack-years, post-bronchodilator FEV1 ≥30% and 1/FVC 1 at Day 28. Results 385 patients (mean age 61.2 years; mean post-bronchodilator FEV1 53% predicted were randomized; 88.6% completed. All OD and BID dosing regimens produced dose-dependent bronchodilation; at Day 28, increases in mean trough FEV1 versus placebo were statistically significant for all regimens, ranging from 51 mL (glycopyrronium bromide 12.5 μg OD to 160 mL (glycopyrronium bromide 50 μg BID. Pharmacodynamic steady-state was reached by Day 7. There was a small separation (≤37 mL between BID and OD dose–response curves for mean trough FEV1 at steady-state in favour of BID dosing. Over 24 hours, separation between OD and BID regimens was even smaller (FEV1 AUC0-24h maximum difference for equivalent daily dose regimens: 8 mL. Dose–response results for FEV1 at 12 hours, FEV1 AUC0-12h and FEV1 AUC0-4h at steady-state showed OD regimens provided greater improvement over placebo than BID regimens for total daily doses of 25 μg, 50 μg and 100 μg, while the reverse was true for OD versus BID regimens from 12–24 hours. The 12.5 μg BID dose produced a marginally higher improvement in trough FEV1 versus placebo than 50 μg OD, however, the response at 12 hours over placebo was suboptimal (74 mL. Glycopyrronium bromide was safe and well tolerated at all doses. Conclusions Glycopyrronium bromide 50 μg OD provides significant bronchodilation over a 24 hour period

  4. The Adhesion Improvement of Cubic Boron Nitride Film on High Speed Steel Substrate Implanted by Boron Element

    Institute of Scientific and Technical Information of China (English)

    CAI Zhi-hai; ZHANG Ping; TAN Jun

    2005-01-01

    Cubic boron nitride(c-BN) films were deposited on W6Mo5Cr4V2 high speed steel(HSS) substrate implanted with boron ion by RF-magnetron sputtering. The films were analyzed by the bending beam method, scratch test, XPS and AFM. The experimental results show that the implantation of boron atom can reduce the in ternal stress and improve the adhesion strength of the films. The critical load of scratch test rises to 27.45 N, compared to 1.75 N of c-BN film on the unimplanted HSS. The AFM shows that the surface of the c-BN film on the implanted HSS is low in roughness and small in grain size. Then the composition of the boron implanted layer was analyzed by the XPS. And the influence of the boron implanted layer on the internal stress and adhesion strength of c-BN films were investigated.

  5. Exploiting the enantioselectivity of Baeyer-Villiger monooxygenases via boron oxidation

    NARCIS (Netherlands)

    Brondani, Patricia B.; Dudek, Hanna; Reis, Joel S.; Fraaije, Marco W.; Andrade, Leandro H.

    2012-01-01

    The enantioselective carbon-boron bond oxidation of several chiral boron-containing compounds by Baeyer-Villiger monooxygenases was evaluated. PAMO and M446G PAMO conveniently oxidized 1-phenylethyl boronate into the corresponding 1-(phenyl)ethanol (ee = 82-91%). Cyclopropyl boronic esters were also

  6. Synthesis of Dimethyl Aryl Acylsulfonium Bromides from Aryl Methyl Ketones in a DMSO-HBr System

    OpenAIRE

    Zhiling Cao; Dahua Shi; Yingying Qu; Chuanzhou Tao; Weiwei Liu; Guowei Yao

    2013-01-01

    A new, simplified method for the synthesis of dimethyl aryl acylsulfonium salts has been developed. A series of dimethyl aryl acylsulfonium bromides were prepared by the reaction of aryl methyl ketones with hydrobromic acid and dimethylsulfoxide (DMSO). This sulfonium salt confirms that bromine production and the bromination reaction take place in the DMSO-HBr oxidation system. What’s more, it is also a key intermediate for the synthesis of arylglyoxals.

  7. The Challenge of Research and Extension to Define and Implement Alternatives to Methyl Bromide

    OpenAIRE

    Noling, J. W.; Becker, J. O.

    1994-01-01

    Over the past 30 years, methyl bromide (MBr), a broad spectrum fumigant, has been used extensively for soilborne disease and pest control in the production of many fruit, vegetable, turf, and nursery crops. Recently, agricultural emissions of MBr were implicated as a potentially significant contributor to stratospheric ozone depletion. As a precautionary measure for global ozone protection, the U.S. Environmental Protection Agency has enforced federal legislation which mandates a complete pha...

  8. Comparison of injection drotaverine and injection valethamate bromide on duration and course of labor

    OpenAIRE

    Pradnya Rajendra Changede

    2016-01-01

    Background: Numerous drugs have been used to shorten the active phase of labor. How rationale is it to use these drugs to shorten the active phase of labor? Do they really shorten the duration of labor? What adverse effects do they have on the baby and the mother? These questions were the basis to perform the present study of comparing two of such drugs, injection drotaverine and injection Valethamate bromide with control subjects. Methods: This was a prospective study conducted in a terti...

  9. Ethidium Bromide MIC Screening for Enhanced Efflux Pump Gene Expression or Efflux Activity in Staphylococcus aureus▿

    OpenAIRE

    Patel, Diixa; Kosmidis, Christos; Seo, Susan M.; Kaatz, Glenn W.

    2010-01-01

    Multidrug resistance efflux pumps contribute to antimicrobial and biocide resistance in Staphylococcus aureus. The detection of strains capable of efflux is time-consuming and labor-intensive using currently available techniques. A simple and inexpensive method to identify such strains is needed. Ethidium bromide is a substrate for all but one of the characterized S. aureus multidrug-resistant (MDR) efflux pumps (NorC), leading us to examine the utility of simple broth microtiter MIC determin...

  10. Effect of Impeller Agitation on Preparation of Tetra-n-Butyl Ammonium Bromide Semiclathrate Hydrate Slurries

    OpenAIRE

    Yoshiro Inoue; Kazunari Ohgaki; Shunsuke Hashimoto; Hiroyuki Ito

    2012-01-01

    The slurries-containing tetra-n-butyl ammonium bromide (TBAB) solution and its semiclathrate hydrate have attracted a lot of interest as latent heat transport media. These hydrate slurries contain some microparticles of crystal, and the size and shape of these hydrate particles could affect the mobility of slurries. Hence, it is essential to investigate the efficient hydrate-slurry preparation methods and the effect of hydrate particles on the fluid property of slurries for the application to...

  11. Mechanism of HERG potassium channel inhibition by tetra-n-octylammonium bromide and benzethonium chloride

    Energy Technology Data Exchange (ETDEWEB)

    Long, Yan; Lin, Zuoxian [Key Laboratory of Regenerative Biology, Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530 (China); Xia, Menghang; Zheng, Wei [National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD 20892 (United States); Li, Zhiyuan, E-mail: li_zhiyuan@gibh.ac.cn [Key Laboratory of Regenerative Biology, Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530 (China)

    2013-03-01

    Tetra-n-octylammonium bromide and benzethonium chloride are synthetic quaternary ammonium salts that are widely used in hospitals and industries for the disinfection and surface treatment and as the preservative agent. Recently, the activities of HERG channel inhibition by these compounds have been found to have potential risks to induce the long QT syndrome and cardiac arrhythmia, although the mechanism of action is still elusive. This study was conducted to investigate the mechanism of HERG channel inhibition by these compounds by using whole-cell patch clamp experiments in a CHO cell line stably expressing HERG channels. Tetra-n-octylammonium bromide and benzethonium chloride exhibited concentration-dependent inhibitions of HERG channel currents with IC{sub 50} values of 4 nM and 17 nM, respectively, which were also voltage-dependent and use-dependent. Both compounds shifted the channel activation I–V curves in a hyperpolarized direction for 10–15 mV and accelerated channel activation and inactivation processes by 2-fold. In addition, tetra-n-octylammonium bromide shifted the inactivation I–V curve in a hyperpolarized direction for 24.4 mV and slowed the rate of channel deactivation by 2-fold, whereas benzethonium chloride did not. The results indicate that tetra-n-octylammonium bromide and benzethonium chloride are open-channel blockers that inhibit HERG channels in the voltage-dependent, use-dependent and state-dependent manners. - Highlights: ► Tetra-n-octylammonium and benzethonium are potent HERG channel inhibitors. ► Channel activation and inactivation processes are accelerated by the two compounds. ► Both compounds are the open-channel blockers to HERG channels. ► HERG channel inhibition by both compounds is use-, voltage- and state dependent. ► The in vivo risk of QT prolongation needs to be studied for the two compounds.

  12. Tiotropium bromide in the routine care of GOLD stage II COPD patients: a pharmaeconomic evaluation

    OpenAIRE

    Orietta Zaniolo; Michela Carsi; Sergio Iannazzo

    2011-01-01

    Background: a secondary pre-specified analysis of the UPLIFT cohort demonstrated that the inclusion of tiotropium bromide in the routine care of GOLD stage II (moderate) chronic obstructive pulmonary disease (COPD) patients is associated with stronger improvements of survival, quality of life, and exacerbation rate than those shown in the total cohort; in this subgroup, tiotropium furthermore induces a significant reduction in the rate of FEV1 decline.Objective: to adapt the Spiriva® model, o...

  13. Matrix Metalloproteinase-9 and -2 Expression in the Olfactory Bulb Following Methyl Bromide Gas Exposure

    OpenAIRE

    Bakos, Stephen R.; Schwob, James E.; Costanzo, Richard M.

    2010-01-01

    Matrix metalloproteinase-9 (MMP-9) and MMP-2 are important for recovery following direct traumatic injury within the central nervous system (CNS). However, most CNS injury models include both direct trauma and neuronal deafferentation. This limits the ability to determine if these MMPs are important to one or both components of injury. To establish if MMPs play a role in the deafferentation processes, we investigated MMP-9 and MMP-2 in the olfactory bulb following methyl bromide gas exposure....

  14. Linear free energy relationship in reactions between diphenyl amine and benzyl bromides

    Indian Academy of Sciences (India)

    S Ranga Reddy; P Manikyamba

    2006-05-01

    Rate of reaction between benzyl bromide and diphenyl amine is retarded by electron-donating groups and enhanced by electron-withdrawing groups present on the benzene ring of the substrate. Hammett's reaction constant of the reaction decreases with increase in temperature according to the equation, \\rho = -11.92 + 3.54/ T. Minimal structural effects observed are attributed to the fact that the isokinetic temperature of the reaction is close to the reaction temperature.

  15. Laboratory Evaluation of Drop-in Solvent Alternatives to n-Propyl Bromide for Vapor Degreasing

    Science.gov (United States)

    Mitchell, Mark A.; Lowrey, Nikki M.

    2012-01-01

    Based on this limited laboratory study, solvent blends of trans-1,2 dichloroethylene with HFEs, HFCs, or PFCs appear to be viable alternatives to n-propyl bromide for vapor degreasing. The lower boiling points of these blends may lead to greater solvent loss during use. Additional factors must be considered when selecting a solvent substitute, including stability over time, VOC, GWP, toxicity, and business considerations.

  16. High resolution single strand conformation polymorphism analysis using formamide and ethidium bromide staining

    OpenAIRE

    Xie, T.; Ho, SL; Ma, OCK

    1997-01-01

    Single strand conformation polymorphism (SSCP) analysis using ethidium bromide can be improved by adding formamide as the denaturant. This gives higher resolution than previous SSCP methods; it had 100% sensitivity in the discrimination of 14 PCR samples from two different genes, even for a long fragment close to the upper limit of 250 base pairs. This modified procedure is a rapid, simple, safe, and yet highly sensitive method for detecting structural differences in DNA fragments.

  17. Use of Br-82 and I-131 radionuclides in studies of thyrotoxic effects of exogenous bromide

    Czech Academy of Sciences Publication Activity Database

    Pavelka, Stanislav

    Vol.3. Kolkata: Saha Institute of Nuclear Physics, 2010 - (Lahiri, S.; Maiti, M.; Das, S.), s. 342-344 ISSN 0973-256X. [Application of Radiotracers in Chemical, Environmental and Biological Sciences. Kolkata (IN), 07.11.2010-13.11.2010] R&D Projects: GA ČR(CZ) GA304/08/0256 Institutional research plan: CEZ:AV0Z50110509 Keywords : bromide * metabolism of iodine * thyrotoxic Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition

  18. Interference of exogenous bromide with the metabolism of thyroid hormones in the rat

    Czech Academy of Sciences Publication Activity Database

    Pavelka, Stanislav

    České Budějovice: -, 2008. s. 205-205. ISBN 80-86313-21-2. [Biochemický sjezd /21./. 14.09.2008-17.09.2008, České Budějovice] Grant ostatní: GA AV ČR(CZ) KJB401630701 Institutional research plan: CEZ:AV0Z50110509 Keywords : spo2 * bromide * metabolism * thyroid hormone Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition

  19. Radiometric quantification of thyrotoxic and goitrogenic effects of exogenous bromide and perchlorate ions

    Czech Academy of Sciences Publication Activity Database

    Pavelka, Stanislav

    Bratislava: Slovenská technická univerzita, 2012, s. 152-156. ISBN 978-80-227-3722-7. [Priemyselná toxikológia 2012 /32./. Svit, Vysoké Tatry (SK), 20.06.2012-22.06.2012] R&D Projects: GA ČR(CZ) GA304/08/0256 Institutional research plan: CEZ:AV0Z50110509 Keywords : bromide * perchlorate * radiometric assay * thyroid peroxidase Subject RIV: ED - Physiology

  20. Synthesis of Dimethyl Aryl Acylsulfonium Bromides from Aryl Methyl Ketones in a DMSO-HBr System

    Directory of Open Access Journals (Sweden)

    Zhiling Cao

    2013-12-01

    Full Text Available A new, simplified method for the synthesis of dimethyl aryl acylsulfonium salts has been developed. A series of dimethyl aryl acylsulfonium bromides were prepared by the reaction of aryl methyl ketones with hydrobromic acid and dimethylsulfoxide (DMSO. This sulfonium salt confirms that bromine production and the bromination reaction take place in the DMSO-HBr oxidation system. What’s more, it is also a key intermediate for the synthesis of arylglyoxals.

  1. Tetrabutylammonium Bromide (TBABr)-Based Deep Eutectic Solvents (DESs) and Their Physical Properties

    OpenAIRE

    Rizana Yusof; Emilia Abdulmalek; Kamaliah Sirat; Mohd. Basyaruddin Abdul Rahman

    2014-01-01

    Density, viscosity and ionic conductivity data sets of deep eutectic solvents (DESs) formed by tetrabutylammonium bromide (TBABr) paired with ethlyene glycol, 1,3-propanediol, 1,5-pentanediol and glycerol hydrogen bond donors (HBDs) are reported. The properties of DES were measured at temperatures between 303 K and 333 K for HBD percentages of 66.7% to 90%. The effects of HBDs under different temperature and percentages are systematically analyzed. As expected, the measured density and viscos...

  2. Tryptophan modification by 2-hydroxy-5-nitrobenzyl bromide studied by MALDI-TOF mass spectrometry

    Czech Academy of Sciences Publication Activity Database

    Strohalm, M.; Kodíček, M.; Pechar, Michal

    2003-01-01

    Roč. 312, č. 3 (2003), s. 811-816. ISSN 0006-291X R&D Projects: GA ČR GA203/02/0922; GA AV ČR KSK4055109 Institutional research plan: CEZ:AV0Z4050913 Keywords : MALDI-TOF mass spectrometry * 2-hydroxy-5-nitrobenzyl bromide * Koshland reagent Subject RIV: CE - Biochemistry Impact factor: 2.836, year: 2003

  3. Replacing conventional carbon nucleophiles with electrophiles: nickel-catalyzed reductive alkylation of aryl bromides and chlorides.

    Science.gov (United States)

    Everson, Daniel A; Jones, Brittany A; Weix, Daniel J

    2012-04-11

    A general method is presented for the synthesis of alkylated arenes by the chemoselective combination of two electrophilic carbons. Under the optimized conditions, a variety of aryl and vinyl bromides are reductively coupled with alkyl bromides in high yields. Under similar conditions, activated aryl chlorides can also be coupled with bromoalkanes. The protocols are highly functional-group tolerant (-OH, -NHTs, -OAc, -OTs, -OTf, -COMe, -NHBoc, -NHCbz, -CN, -SO(2)Me), and the reactions are assembled on the benchtop with no special precautions to exclude air or moisture. The reaction displays different chemoselectivity than conventional cross-coupling reactions, such as the Suzuki-Miyaura, Stille, and Hiyama-Denmark reactions. Substrates bearing both an electrophilic and nucleophilic carbon result in selective coupling at the electrophilic carbon (R-X) and no reaction at the nucleophilic carbon (R-[M]) for organoboron (-Bpin), organotin (-SnMe(3)), and organosilicon (-SiMe(2)OH) containing organic halides (X-R-[M]). A Hammett study showed a linear correlation of σ and σ(-) parameters with the relative rate of reaction of substituted aryl bromides with bromoalkanes. The small ρ values for these correlations (1.2-1.7) indicate that oxidative addition of the bromoarene is not the turnover-frequency determining step. The rate of reaction has a positive dependence on the concentration of alkyl bromide and catalyst, no dependence upon the amount of zinc (reducing agent), and an inverse dependence upon aryl halide concentration. These results and studies with an organic reductant (TDAE) argue against the intermediacy of organozinc reagents. PMID:22463689

  4. Boron nitride - boron hybrid coating on uranium dioxide-gadolinium oxide fuel. Final report for the period 1 November 1996 - 1 November 1997

    International Nuclear Information System (INIS)

    The report describes work to develop laboratory-scale technology of the deposition of hybrid boron nitrate-metallic boron coating onto the surface of uranium dioxide ore uranium dioxide - gadolinia dioxide fuel pellets. Methods of chemical vapour deposition and plasma enhanced chemical vapour deposition were used in the Department of Chemical Engineering of the Middle East Technical University, Ankara, Turkey. An excellent adherence of boron onto the boron nitrate layer and boron nitrate layer onto the fuel pellet surface was demonstrated. Fine grain-type structure of boron coating and its excellent adherence are good indices for integrated fuel burnable absorber fuels

  5. Crystallography, semiconductivity, thermoelectricity, and other properties of boron and its compounds, especially B6O

    Science.gov (United States)

    Slack, G. A.; Morgan, K. E.

    2015-09-01

    Electron deficient and non-deficient boron compounds are discussed as potential thermoelectric generator materials. Particular attention is paid to carbon-doped beta-boron, high-carbon boron carbide, and the alpha-boron derivative compound boron suboxide. Stoichiometric B6O shows some promise, and may have a higher ZT than the other two compounds. Carbon saturated beta-boron appears to have a higher ZT than undoped samples. Carbon saturated boron carbide at B12C3 does exist. Its thermoelectric behavior is unknown.

  6. Efficient boron-carbon-nitrogen nanotube formation via combined laser-gas flow levitation

    Energy Technology Data Exchange (ETDEWEB)

    Whitney, R Roy; Jordan, Kevin; Smith, Michael W

    2015-03-24

    A process for producing boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula B.sub.xC.sub.yN.sub.z. The process utilizes a combination of laser light and nitrogen gas flow to support a boron ball target during heating of the boron ball target and production of a boron vapor plume which reacts with nitrogen or nitrogen and carbon to produce boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula B.sub.xC.sub.yN.sub.z.

  7. Efficient boron nitride nanotube formation via combined laser-gas flow levitation

    Energy Technology Data Exchange (ETDEWEB)

    Whitney, R. Roy; Jordan, Kevin; Smith, Michael

    2014-03-18

    A process for producing boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula B.sub.xC.sub.yN.sub.z. The process utilizes a combination of laser light and nitrogen gas flow to support a boron ball target during heating of the boron ball target and production of a boron vapor plume which reacts with nitrogen or nitrogen and carbon to produce boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula B.sub.xC.sub.yN.sub.z.

  8. Efficient Boron-Carbon-Nitrogen Nanotube Formation Via Combined Laser-Gas Flow Levitation

    Science.gov (United States)

    Whitney, R. Roy (Inventor); Jordan, Kevin (Inventor); Smith, Michael W. (Inventor)

    2015-01-01

    A process for producing boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula BxCyNz. The process utilizes a combination of laser light and nitrogen gas flow to support a boron ball target during heating of the boron ball target and production of a boron vapor plume which reacts with nitrogen or nitrogen and carbon to produce boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula BxCyNz.

  9. Efficient Boron Nitride Nanotube Formation via Combined Laser-Gas Flow Levitation

    Science.gov (United States)

    Whitney, R. Roy (Inventor); Jordan, Kevin (Inventor); Smith, Michael W. (Inventor)

    2014-01-01

    A process for producing boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula B(sub x)C(sub y)N(sub z) The process utilizes a combination of laser light and nitrogen gas flow to support a boron ball target during heating of the boron ball target and production of a boron vapor plume which reacts with nitrogen or nitrogen and carbon to produce boron nitride nanotubes and/or boron-carbon-nitrogen nanotubes of the general formula B(sub x)C(sub y)N(sub z).

  10. Application of Cycloaddition Reactions to the Syntheses of Novel Boron Compounds

    Directory of Open Access Journals (Sweden)

    John A. Maguire

    2010-12-01

    Full Text Available This review covers the application of cycloaddition reactions in forming the boron-containing compounds such as symmetric star-shaped boron-enriched dendritic molecules, nano-structured boron materials and aromatic boronic esters. The resulting boron compounds are potentially important reagents for both materials science and medical applications such as in boron neutron capture therapy (BNCT in cancer treatment and as drug delivery agents and synthetic intermediates for carbon-carbon cross-coupling reactions. In addition, the use of boron cage compounds in a number of cycloaddition reactions to synthesize unique aromatic species will be reviewed briefly.

  11. Ethidium Bromide MIC Screening for Enhanced Efflux Pump Gene Expression or Efflux Activity in Staphylococcus aureus▿

    Science.gov (United States)

    Patel, Diixa; Kosmidis, Christos; Seo, Susan M.; Kaatz, Glenn W.

    2010-01-01

    Multidrug resistance efflux pumps contribute to antimicrobial and biocide resistance in Staphylococcus aureus. The detection of strains capable of efflux is time-consuming and labor-intensive using currently available techniques. A simple and inexpensive method to identify such strains is needed. Ethidium bromide is a substrate for all but one of the characterized S. aureus multidrug-resistant (MDR) efflux pumps (NorC), leading us to examine the utility of simple broth microtiter MIC determinations using this compound in identifying efflux-proficient strains. Quantitative reverse transcription-PCR identified the increased expression of one or more MDR efflux pump genes in 151/309 clinical strains (49%). Ethidium bromide MIC testing was insensitive (48%) but specific (92%) in identifying strains with gene overexpression, but it was highly sensitive (95%) and specific (99%) in identifying strains capable of ethidium efflux. The increased expression of norA with or without other genes was most commonly associated with efflux, and in the majority of cases that efflux was inhibited by reserpine. Ethidium bromide MIC testing is a simple and straightforward method to identify effluxing strains and can provide accurate predictions of efflux prevalence in large strain sets in a short period of time. PMID:20855743

  12. Transport of bromide measured by soil coring, suction plates, and lysimeters under transient flow conditions.

    Science.gov (United States)

    Kasteel, R.; Pütz, Th.; Vereecken, H.

    2003-04-01

    Lysimeter studies are one step within the registration procedure of pesticides. Flow and transport in these free-draining lysimeters do not reflect the field situation mainly because of the occurence of a zone of local saturation at the lower boundary (seepage face). The objective of this study is to evaluate the impact of flow and transport behaviour of bromide detected with different measuring devices (lysimeters, suction plates, and soil coring) by comparing experimental results with numerical simulations in heterogeneous flow domains. We applied bromide as a small pulse to the bare soil surface (Orthic Luvisol) of the three devices and the displacement of bromide was regurlarly sampled for three years under natural wheather conditions. Based on the mean breakthrough curves we observe experimentally that lysimeters have a lower effective pore-water velocity and exhibit more solute spreading resulting in a larger dispersivity than the suction plates. This can be ascribed to the artefact of the lower boundary. We performed numerical transport simulations in 2-D heterogeneous flow fields (scaling approach) choosing appropriate boundary conditions for the various devices. The simulations allow to follow the temporal evolution of flow and transport processes in the various devices and to gain additional process understanding. We conclude that the model is essentially capable to reproduce the main experimental findings only if we account for the spatial correlation structure of the hydraulic properties, i.e. soil heterogeneity.

  13. A bio-product as alternative to methyl bromide for replant disease control on strawberry

    Institute of Scientific and Technical Information of China (English)

    Yu ZHANG; Tongle HU; Lijing JI; Keqiang CAO

    2008-01-01

    Pre-plant soil fumigation with methyl bromide (MB) is a standard practice for controlling soil-borne diseases especially for strawberry diseases. However, the application of MB will be forbidden in China in the year 2015. For this reason, a bio-product named Kangdi 3 was tested as an alternative to MB in strawberry greenhouses in Mancheng (Hebei Province) and Donggang (Liaoning province), China in 2005 and 2006. Methyl bromide at a normal dosage of 500 kg/hm2 and Kangdi 3 at three dosages of 750, 1500 and 2250 kg/hm2 were tested. Plots without any treatment were used as the control. During the growing stage, assessments were made on fungal communities in rhizosphere, growth status of strawberry, the disease levels on roots as well as the yields. Results showed that Kangdi 3 significantly reduced the quantity of fungi and the disease index, while enhancing strawberry growth and the yields compared with the untreated control. Therefore, Kangdi 3 is a great potential substitute for methyl bromide to control replant diseases in strawberry.

  14. Recent trends in atmospheric methyl bromide: analysis of post-Montreal Protocol variability

    Directory of Open Access Journals (Sweden)

    S. A. Yvon-Lewis

    2009-03-01

    Full Text Available The atmospheric methyl bromide (CH3Br burden has declined in recent years, in response to the phaseout of agricultural and structural fumigation consumption under the amendments to the Montreal Protocol. The timing and magnitude of this decrease represents an opportunity to examine our current understanding of the CH3Br budget, the phaseout schedule, and recent estimates of interannual variability in biomass burning and global OH. In this study, simulations obtained from a time-dependent global model of atmospheric CH3Br emissions and uptake are compared to observations from the NOAA flask network. The model includes an updated global methyl bromide source inventory that includes biofuel combustion emissions estimated at 6.1±3 Gg yr−1 globally. The phaseout of CH3Br production for agricultural uses began in 1998, concurrent with the pulse in biomass burning associated with the 1998 El Niño. The combined effects of three factors (biomass burning, global OH, and anthropogenic phaseout appear to explain most of the observed atmospheric methyl bromide trend over the 1997–2005 period. The global budget remains imbalanced, with a large missing source. These results suggest that more than 80% of the missing source does not exhibit significant interannual variability during the phaseout period and, therefore, does not result from underestimating agricultural CH3Br emissions.

  15. Preparation and optical characteristics of layered perovskite-type lead-bromide-incorporated azobenzene chromophores

    Energy Technology Data Exchange (ETDEWEB)

    Sasai, Ryo, E-mail: rsasai@riko.shimane-u.ac.jp [Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, F3-3(250), Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Shinomura, Hisashi [Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, F3-3(250), Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

    2013-02-15

    Lead bromide-based layered perovskite powders with azobenzene derivatives were prepared by a homogeneous precipitation method. From the diffuse reflectance (DR) and photoluminescence (PL) spectra of the hybrid powder materials, the present hybrids exhibited sharp absorption and PL peaks originating from excitons produced in the PbBr{sub 4}{sup 2-} layer. When the present hybrid powder was irradiated with UV light at 350 nm, the absorption band from the trans-azobenzene chromophore, observed around 350 nm, decreased, while the absorption band from the cis-azobenzene chromophore, observed around 450 nm, increased. These results indicate that azobenzene chromophores in the present hybrid materials exhibit reversible photoisomerization. Moreover, it was found that the PL intensity from the exciton also varied due to photoisomerization of the azobenzene chromophores in the present hybrid. Thus, for the first time we succeeded in preparing the azobenzene derivative lead-bromide-based layered perovskite with photochromism before and after UV light irradiation. - Graphical abstract: For the first time, we succeeded in preparing the azobenzene derivative lead-bromide-based layered perovskite with photochromism before and after UV light irradiation. Highlights: Black-Right-Pointing-Pointer PbBr-based layered perovskite with azobenezene derivatives could be synthesized by a homogeneous precipitation method. Black-Right-Pointing-Pointer Azobenzene derivatives incorporated the present hybrid that exhibited reversible photoisomerization under UV and/or visible light irradiation. Black-Right-Pointing-Pointer PL property of the present hybrid could also be varied by photoisomerization.

  16. Preparation and optical characteristics of layered perovskite-type lead-bromide-incorporated azobenzene chromophores

    International Nuclear Information System (INIS)

    Lead bromide-based layered perovskite powders with azobenzene derivatives were prepared by a homogeneous precipitation method. From the diffuse reflectance (DR) and photoluminescence (PL) spectra of the hybrid powder materials, the present hybrids exhibited sharp absorption and PL peaks originating from excitons produced in the PbBr42− layer. When the present hybrid powder was irradiated with UV light at 350 nm, the absorption band from the trans-azobenzene chromophore, observed around 350 nm, decreased, while the absorption band from the cis-azobenzene chromophore, observed around 450 nm, increased. These results indicate that azobenzene chromophores in the present hybrid materials exhibit reversible photoisomerization. Moreover, it was found that the PL intensity from the exciton also varied due to photoisomerization of the azobenzene chromophores in the present hybrid. Thus, for the first time we succeeded in preparing the azobenzene derivative lead-bromide-based layered perovskite with photochromism before and after UV light irradiation. - Graphical abstract: For the first time, we succeeded in preparing the azobenzene derivative lead-bromide-based layered perovskite with photochromism before and after UV light irradiation. Highlights: ► PbBr-based layered perovskite with azobenezene derivatives could be synthesized by a homogeneous precipitation method. ► Azobenzene derivatives incorporated the present hybrid that exhibited reversible photoisomerization under UV and/or visible light irradiation. ► PL property of the present hybrid could also be varied by photoisomerization.

  17. Continuous Inhalation of Ipratropium Bromide for Acute Asthma Refractory to β2-agonist Treatment.

    Science.gov (United States)

    Koumbourlis, Anastassios C; Mastropietro, Christopher

    2015-01-01

    To present the case of a patient with persistent bronchospasm, refractory to treatment with β2-agonists, that resolved promptly with continuous inhalation of large dose (1000 mcg/hr) ipratropium bromide, and to discuss the possibility of tolerance to β2-agonists as the cause for his failure to respond to adrenergic medications. The patient had received multiple doses of albuterol, as well as subcutaneous terbutaline (0.3 mg), intravenous magnesium sulfate (1 g) and intravenous dexamethasone (10 mg) prior to his admission to the intensive care unit. He remained symptomatic despite systemic intravenous steroids, continuous intravenous terbutaline (up to 0.6 mcg/kg/min), and continuous nebulized albuterol (up to 20 mg/hr for 57 hr) followed by 49 hours of continuous levalbuterol (7 mg/hr). Due to the lack of response, all β2-agonists were discontinued at 106 hours post-admission, and he was started on large dose ipratropium bromide (1000 mcg/hr) by continuous nebulization. Clinical improvement was evident within 1 hour and complete resolution of his symptoms within 4 hours. Continuous inhalation of large dose ipratropium bromide may be an effective regimen for the treatment of patients hospitalized with acute asthma who are deemed to be nonresponsive and/or tolerant to β2-agonist therapy. PMID:25859173

  18. Managing opioid-induced constipation in advanced illness: focus on methylnaltrexone bromide

    Directory of Open Access Journals (Sweden)

    Katri Elina Clemens

    2010-02-01

    Full Text Available Katri Elina Clemens1,2, Eberhard Klaschik11Department of Science and Research, Centre for Palliative Medicine, University of Bonn, Germany; 2Department of Palliative Medicine and Pain Therapy, Malteser Hospital Bonn/Rhein-Sieg, GermanyAbstract: Constipation is a common symptom in palliative care patients which can generate considerable suffering. There is uncertainty about the choice of treatment options from varying recommendations for management of constipation and a varying clinical practice in palliative care settings. The purpose of the review was to evaluate the current recommendations of therapy guidelines for the management of opioid-induced constipation in palliative care patients with a focus on methylnaltrexone bromide. Recent findings in the literature and related information on the opioid-induced gastrointestinal disorders in patients with advanced illness, as well as information on the opioid-antagonist methylnaltrexone, are discussed. Knowledge of the role of definitions, the causes of constipation and the pathophysiology of opioid-induced constipation must be given high priority in the treatment of patients receiving opioids. Diagnosis and therapy of constipation, therefore, should relate to findings in clinical investigation. Opioid-induced constipation and its adequate treatment is an important issue for patients with advanced illness and also poses therapeutic challenge for clinicians in daily routine. Methylnaltrexone bromide may represent an important therapeutic option for palliative care patients who are suffering from opioid-induced constipation with failure of conventional prophylactic oral laxative treatment.Keywords: opioid-induced constipation, palliative care, opioids, methylnaltrexone bromide

  19. Room temperature synthesis of silver nanowires from tabular silver bromide crystals in the presence of gelatin

    International Nuclear Information System (INIS)

    Long silver nanowires were synthesized at room temperature by a simple and fast process derived from the development of photographic films. A film consisting of an emulsion of tabular silver bromide grains in gelatin was treated with a photographic developer (4-(methylamino)phenol sulfate (metol), citric acid) in the presence of additional aqueous silver nitrate. The silver nanowires have lengths of more than 50 μm, some even more than 100 μm, and average diameters of about 80 nm. Approximately, 70% of the metallic silver formed in the reduction consists of silver nanowires. Selected area electron diffraction (SAED) results indicate that the silver nanowires grow along the [111] direction. It was found that the presence of gelatin, tabular silver bromide crystals and silver ions in solution are essential for the formation of the silver nanowires. The nanowires appear to originate from the edges of the silver bromide crystals. They were characterized by transmission electron microscopy (TEM), SAED, scanning electron microscopy (SEM), and powder X-ray diffraction (XRD)

  20. Flight Experiment to Study Double-Diffusive Instabilities in Silver-Doped Lead Bromide Crystals

    Science.gov (United States)

    Singh, N. B.; Rosch, W. R.; Suhre, D. R.; Coriell, S. R.; Duval, W. M. B.

    1999-01-01

    A detailed study on the effect of convection on crystal quality was carried out by growing lead bromide crystals in transparent Bridgman furnace. Direct observations were made on the solid-liquid interface and a new kind of instability was observed. This could be explained on the basis of toroidal flow in the AgBr-doped lead bromide sample. With the increasing translation velocity, the interface changed from flat to depressed, and then formed a cavity in the center of the growth tube. The crystal grown at the lowest thermal Rayleigh number showed the highest quality and crystal grown at the largest thermal Rayleigh number showed the worst quality. Numerical studies were carried out to provide a framework for interpreting the observed convective and morphological instabilities, and to determine the critical (limiting) concentration of dopant for a particular growth velocity and gravity level. Theoretical instability diagrams were compared with data obtained from the experimental studies. These studies provided basic data on convective behavior in doped lead bromide crystals grown by the commercially important Bridgman process.