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Sample records for acrylonitrile stanniciv tungstate

  1. Acrylonitrile

    Integrated Risk Information System (IRIS)

    Acrylonitrile ; CASRN 107 - 13 - 1 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Eff

  2. Acrylonitrile butadiene rubber (NBR)/manganous tungstate (MnWO4) nanocomposites: Characterization, mechanical and electrical properties

    NASA Astrophysics Data System (ADS)

    Ramesan, M. T.; Abdu Raheem V., P.; Jayakrishnan, P.; Pradyumnan, P. P.

    2014-10-01

    Nanocomposites of NBR with manganous-tungstate nanoparticles were prepared through vulcanization process. The extent of interaction of nanoparticles with the polymer was studied by FTIR, SEM, XRD, TGA and AC conductivity. FTIR and XRD ascertain the interaction of NBR with MnWO4 nanoparticles. SEM analysis established that the nanopartilces were well dispersed in the macromolecular chain of NBR. The mechanical properties of the nanocomposites were studied as a function of filler loading. The nanocomposites exhibited enhanced thermal stability as seen in TGA. Conductivity and dielectric properties of nanocomposites increase with increase in concentration of MnWO4 nanoparticles (7phr) and thereafter the value decreases.

  3. Mutagenic studies with acrylonitrile.

    PubMed

    Milvy, P; Wolff, M

    1977-07-01

    The mutagenicity of acrylonitrile (vinyl cyanide, propenenitrile) has been demonstrated in the Ames Salmonella typhimurium/liver microsome assay system. Acrylonitrile, in the presence of a mouse liver homogenate produced mutations in the TA 1535, TA 1538 and TA 1978 strains. Exposure of the bacteria was achieved by spotting the acrylonitrile on a "lawn" of salmonella, by shaking a reaction mixture consisting of bacteria, liver homogenate and acrylonitrile, and by exposing the homogenate and bacteria to an atmosphere containing the acrylonitrile. Mutagenesis by this latter method was observed at exposures as low as 57 ppm, less than three times the TLV of 20 ppm that is designated in the United States.

  4. Vanadate, molybdate and tungstate for orthomolecular medicine.

    PubMed

    Matsumoto, J

    1994-09-01

    Recent studies indicate that oxyanions, such as vanadate (V) or vanadyl (IV), cause insulin-like effects on rats by stimulating the insulin receptor tyrosine kinase. Tungstate (VI) and molybdate (VI) show the same effects on rat adipocytes and hepatocytes. Results of uncontrolled trials on volunteers accumulated in Japan also suggest that tungstate effectively regulates diabetes mellitus without detectable side effects. Since these oxyanions naturally exist in organisms, oxyanion therapy, the oral administration of vanadate, vanadyl, molybdate, or tungstate, can be considered to be orthomolecular medicine. Therefore, these oxyanions may provide a viable alternative to chemotherapy. Many diseases in addition to diabetes mellitus might also be treated since the implication of these results is that tyrosine kinases are involved in a variety of diseases. PMID:7815975

  5. Morphology Tuning of Strontium Tungstate Nanoparticles

    SciTech Connect

    Joseph, S.; George, T.; George, K. C.; Sunny, A. T.; Mathew, S.

    2007-08-22

    Strontium tungstate nanocrystals in two different morphologies are successfully synthesized by controlled precipitation in aqueous and in poly vinyl alcohol (PVA) medium. Structural characterizations are carried out by XRD and SEM. The average particle size calculated for the SrWO4 prepared in the two different solvents ranges 20-24 nm. The SEM pictures show that the surface morphologies of the SrWO4 nanoparticles in aqueous medium resemble mushroom and the SrWO4 nanoparticles in PVA medium resemble cauliflower. Investigations on the room temperature luminescent properties of the strontium tungstate nanoparticles prepared in aqueous and PVA medium shows strong emissions around 425 nm.

  6. Ion-Molecule Association in Acrylonitrile

    NASA Technical Reports Server (NTRS)

    Wilson, Paul F.; Milligan, Daniel B.; McEwan, Murray J.

    1997-01-01

    Acrylonitrile (propernenitrile or vinyl cyanide) polymerizes readily via a radical mechanism in solution at room temparature. The propensity to polymerize is sufficiently strong that it is usual to add a radical scavenger to the solution to prevent polymerization when oxygen (an inhibitor) is removed. Polymerization of acrylonitrile is also know to occur via nucleophilic addition of an anion by a michael-type reaction.

  7. 40 CFR 721.505 - Halogenated acrylonitrile.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.505 Halogenated acrylonitrile. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as halogenated acrylonitrile, (PMN P-90-299)...

  8. 40 CFR 721.505 - Halogenated acrylonitrile.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.505 Halogenated acrylonitrile. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as halogenated acrylonitrile, (PMN P-90-299)...

  9. 21 CFR 181.32 - Acrylonitrile copolymers and resins.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Acrylonitrile copolymers and resins. 181.32...-Sanctioned Food Ingredients § 181.32 Acrylonitrile copolymers and resins. (a) Acrylonitrile copolymers and resins listed in this section, containing less than 30 percent acrylonitrile and complying with...

  10. Synthesis, structure characterization and catalytic activity of nickel tungstate nanoparticles

    NASA Astrophysics Data System (ADS)

    Pourmortazavi, Seied Mahdi; Rahimi-Nasrabadi, Mehdi; Khalilian-Shalamzari, Morteza; Zahedi, Mir Mahdi; Hajimirsadeghi, Seiedeh Somayyeh; Omrani, Ismail

    2012-12-01

    Taguchi robust design was applied to optimize experimental parameters for controllable, simple and fast synthesis of nickel tungstate nanoparticles. NiWO4 nanoparticles were synthesized by precipitation reaction involving addition of nickel ion solution to the tungstate aqueous reagent and then formation of nickel tungstate nucleolus which are insoluble in aqueous media. Effects of various parameters such as nickel and tungstate concentrations, flow rate of reagent addition and reactor temperature on diameter of synthesized nickel tungstate nanoparticles were investigated experimentally by the aid of orthogonal array design. The results for analysis of variance (ANOVA) showed that particle size of nickel tungstate can be effectively tuned by controlling significant variables involving nickel and tungstate concentrations and flow rate; while, temperature of the reactor has a no considerable effect on the size of NiWO4 particles. The ANOVA results proposed the optimum conditions for synthesis of nickel tungstate nanoparticles via this technique. Also, under optimum condition nanoparticles of NiWO4 were prepared and their structure and chemical composition were characterized by means of EDAX, XRD, SEM, FT-IR spectroscopy, UV-vis spectroscopy, and photoluminescence. Finally, catalytic activity of the nanoparticles in a cycloaddition reaction was examined.

  11. 21 CFR 181.32 - Acrylonitrile copolymers and resins.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Acrylonitrile copolymers and resins. 181.32 Section... Ingredients § 181.32 Acrylonitrile copolymers and resins. (a) Acrylonitrile copolymers and resins listed in... of the vinyl chloride resin) resin—for use only in contact with oleomargarine. (iv)...

  12. 21 CFR 181.32 - Acrylonitrile copolymers and resins.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) PRIOR-SANCTIONED FOOD INGREDIENTS Specific Prior-Sanctioned Food Ingredients § 181.32 Acrylonitrile copolymers and resins. (a) Acrylonitrile copolymers and... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Acrylonitrile copolymers and resins....

  13. 21 CFR 181.32 - Acrylonitrile copolymers and resins.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) PRIOR-SANCTIONED FOOD INGREDIENTS Specific Prior-Sanctioned Food Ingredients § 181.32 Acrylonitrile copolymers and resins. (a) Acrylonitrile copolymers and... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Acrylonitrile copolymers and resins....

  14. IRIS Toxicological Review of Acrylonitrile (External Review Draft)

    EPA Science Inventory

    [UPDATE] New Schedule for IRIS Acrylonitrile Assessment

    In May 2012, EPA developed a new schedule for completing the IRIS acrylonitrile assessment. Acrylonitrile is primarily used in the manufacture of acrylic and modacrylic fibers, plastics, and nitrile rubbers. It ...

  15. 29 CFR 1915.1045 - Acrylonitrile.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 7 2011-07-01 2011-07-01 false Acrylonitrile. 1915.1045 Section 1915.1045 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) OCCUPATIONAL SAFETY AND HEALTH STANDARDS FOR SHIPYARD EMPLOYMENT Toxic and Hazardous...

  16. 29 CFR 1915.1045 - Acrylonitrile.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Acrylonitrile. 1915.1045 Section 1915.1045 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) OCCUPATIONAL SAFETY AND HEALTH STANDARDS FOR SHIPYARD EMPLOYMENT Toxic and Hazardous...

  17. In situ growth of epitaxial cerium tungstate (100) thin films.

    PubMed

    Skála, Tomáš; Tsud, Nataliya; Orti, Miguel Ángel Niño; Menteş, Tevfik Onur; Locatelli, Andrea; Prince, Kevin Charles; Matolín, Vladimír

    2011-04-21

    The deposition of ceria on a preoxidized W(110) crystal at 870 K has been studied in situ by photoelectron spectroscopy and low-energy electron diffraction. Formation of an epitaxial layer of crystalline cerium tungstate Ce(6)WO(12)(100), with the metals in the Ce(3+) and W(6+) chemical states, has been observed. The interface between the tungsten substrate and the tungstate film consists of WO suboxide. At thicknesses above 0.89 nm, cerium dioxide grows on the surface of Ce(6)WO(12), favoured by the limited diffusion of tungsten from the substrate. PMID:21399780

  18. Synchrotron-based far-infrared spectroscopy of nickel tungstate

    NASA Astrophysics Data System (ADS)

    Kalinko, A.; Kuzmin, A.; Roy, P.; Evarestov, R. A.

    2016-07-01

    Monoclinic antiferromagnetic NiWO4 was studied by far-infrared (30-600 cm-1) absorption spectroscopy in the temperature range of 5-300 K using the synchrotron radiation from SOLEIL source. Two isomorphous CoWO4 and ZnWO4 tungstates were investigated for comparison. The phonon contributions in the far-infrared range of tungstates were interpreted using the first-principles spin-polarized linear combination of atomic orbital calculations. No contributions from magnetic excitations were found in NiWO4 and CoWO4 below their Neel temperatures down to 5 K.

  19. ABSORPTION OF CO2 IN HIGH ACRYLONITRILE CONTENT COPOLYMERS: DEPENDENCE ON ACRYLONITRILE CONTENT. (R829555)

    EPA Science Inventory

    In continuation of our goal to determine the ability of CO2 to plasticize acrylonitrile (AN) copolymers and facilitate melt processing at temperatures below the onset of thermal degradation, a systematic study has been performed to determine the influence of AN cont...

  20. 21 CFR 177.1480 - Nitrile rubber modified acrylonitrile-methyl acrylate copolymers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Nitrile rubber modified acrylonitrile-methyl... Nitrile rubber modified acrylonitrile-methyl acrylate copolymers. Nitrile rubber modified acrylonitrile... rubber modified acrylonitrile-methyl acrylate copolymers consist of basic copolymers produced by...

  1. 21 CFR 177.1480 - Nitrile rubber modified acrylonitrile-methyl acrylate copolymers.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Nitrile rubber modified acrylonitrile-methyl... Nitrile rubber modified acrylonitrile-methyl acrylate copolymers. Nitrile rubber modified acrylonitrile... rubber modified acrylonitrile-methyl acrylate copolymers consist of basic copolymers produced by...

  2. 21 CFR 177.1480 - Nitrile rubber modified acrylonitrile-methyl acrylate copolymers.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Nitrile rubber modified acrylonitrile-methyl... Nitrile rubber modified acrylonitrile-methyl acrylate copolymers. Nitrile rubber modified acrylonitrile... rubber modified acrylonitrile-methyl acrylate copolymers consist of basic copolymers produced by...

  3. 21 CFR 177.1480 - Nitrile rubber modified acrylonitrile-methyl acrylate copolymers.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Nitrile rubber modified acrylonitrile-methyl... Nitrile rubber modified acrylonitrile-methyl acrylate copolymers. Nitrile rubber modified acrylonitrile... rubber modified acrylonitrile-methyl acrylate copolymers consist of basic copolymers produced by...

  4. Elasto-optic effect anisotropy in calcium tungstate crystals.

    PubMed

    Demyanyshyn, N M; Mytsyk, B G; Kost, Y P; Solskii, I M; Sakharuk, O M

    2015-03-20

    The anisotropy of piezo- and elasto-optic effects in calcium tungstate CaWO4 crystals was studied by the indicatory surfaces method. On the basis of the maximum surfaces of the elasto-optic effect, the geometry of acousto-optic interaction with maximum efficiency was found. PMID:25968520

  5. [Migrants from disposable gloves and residual acrylonitrile].

    PubMed

    Wakui, C; Kawamura, Y; Maitani, T

    2001-10-01

    Disposable gloves made from polyvinyl chloride with and without di(2-ethylhexyl) phthalate (PVC-DEHP, PVC-NP), polyethylene (PE), natural rubber (NR) and nitrile-butadiene rubber (NBR) were investigated with respect to evaporation residue, migrated metals, migrants and residual acrylonitrile. The evaporation residue found in n-heptane was 870-1,300 ppm from PVC-DEHP and PVC-NP, which was due to the plasticizers. Most of the PE gloves had low evaporation residue levels and migrants, except for the glove designated as antibacterial, which released copper and zinc into 4% acetic acid. For the NR and NBR gloves, the evaporation residue found in 4% acetic acid was 29-180 ppm. They also released over 10 ppm of calcium and 6 ppm of zinc into 4% acetic acid, and 1.68-8.37 ppm of zinc di-ethyldithiocarbamate and zinc di-n-butyldithiocarbamate used as vulcanization accelerators into n-heptane. The acrylonitrile content was 0.40-0.94 ppm in NBR gloves. PMID:11775358

  6. Growth of transition metals on cerium tungstate model catalyst layers

    NASA Astrophysics Data System (ADS)

    Skála, T.; Tsud, N.; Stetsovych, V.; Mysliveček, J.; Matolín, V.

    2016-10-01

    Two model catalytic metal/oxide systems were investigated by photoelectron spectroscopy and scanning tunneling microscopy. The mixed-oxide support was a cerium tungstate epitaxial thin layer grown in situ on the W(1 1 0) single crystal. Active particles consisted of palladium and platinum 3D islands deposited on the tungstate surface at 300 K. Both metals were found to interact weakly with the oxide support and the original chemical state of both support and metals was mostly preserved. Electronic and morphological changes are discussed during the metal growth and after post-annealing at temperatures up to 700 K. Partial transition-metal coalescence and self-cleaning from the CO and carbon impurities were observed.

  7. Growth of transition metals on cerium tungstate model catalyst layers.

    PubMed

    Skála, T; Tsud, N; Stetsovych, V; Mysliveček, J; Matolín, V

    2016-10-01

    Two model catalytic metal/oxide systems were investigated by photoelectron spectroscopy and scanning tunneling microscopy. The mixed-oxide support was a cerium tungstate epitaxial thin layer grown in situ on the W(1 1 0) single crystal. Active particles consisted of palladium and platinum 3D islands deposited on the tungstate surface at 300 K. Both metals were found to interact weakly with the oxide support and the original chemical state of both support and metals was mostly preserved. Electronic and morphological changes are discussed during the metal growth and after post-annealing at temperatures up to 700 K. Partial transition-metal coalescence and self-cleaning from the CO and carbon impurities were observed. PMID:27494195

  8. EFFECT OF TUNGSTATE ON THE UPTAKE AND FUNCTION OF MOLYBDATE IN AZOTOBACTER AGILIS

    PubMed Central

    Bulen, William A.

    1961-01-01

    Bulen, William A. (Charles F. Kettering Foundation, Yellow Springs, Ohio). Effect of tungstate on the uptake and function of molybdate in Azotobacter agilis. J. Bacteriol. 82:130–134. 1961.—The reported competitive inhibition of molybdate by tungstate was investigated in an effort to elucidate molybdenum functions associated with nitrogen fixation by Azotobacter agilis (A. vinelandii). Growth, respiration, and N215-incorporation experiments with normal and molybdenum-deficient cells indicated that tungstate inhibits the uptake of molybdate but does not compete with the metabolically functional molybdenum of cells metabolizing N2. Neither a molybdenum requirement nor a tungstate inhibition was observed with cells metabolizing urea. PMID:16561910

  9. Structure and thermal behavior of zirconium tungstate under heating

    NASA Astrophysics Data System (ADS)

    Dedova, E. S.; Shutilova, E. S.; Geber, R.; Gomze, L. A.; Kulkov, S. N.

    2016-07-01

    The morphology and properties of powders ZrW2O7(OH)2·2H2O and ZrW2O8, obtained under the conditions of hydrothermal synthesis was studied. Using the high-temperature X-ray analysis, the mechanism of formation of zirconium tungstate was established. The influence of temperature on the structure and properties of materials was studied using shadow-casting method.

  10. A functional leptin system is essential for sodium tungstate antiobesity action.

    PubMed

    Canals, Ignasi; Carmona, María C; Amigó, Marta; Barbera, Albert; Bortolozzi, Analía; Artigas, Francesc; Gomis, Ramon

    2009-02-01

    Sodium tungstate is a novel agent in the treatment of obesity. In diet-induced obese rats, it is able to reduce body weight gain by increasing energy expenditure. This study evaluated the role of leptin, a key regulator of energy homeostasis, in the tungstate antiobesity effect. Leptin receptor-deficient Zucker fa/fa rats and leptin-deficient ob/ob mice were treated with tungstate. In lean animals, tungstate administration reduced body weight gain and food intake and increased energy expenditure. However, in animals with deficiencies in the leptin system, treatment did not modify these parameters. In ob/ob mice in which leptin deficiency was restored through adipose tissue transplantation, treatment restored the tungstate-induced body weight gain and food intake reduction as well as energy expenditure increase. Furthermore, in animals in which tungstate administration increased energy expenditure, changes in the expression of key genes involved in brown adipose tissue thermogenesis were detected. Finally, the gene expression of the hypothalamic neuropeptides, Npy, Agrp, and Cart, involved in the leptin regulation of energy homeostasis, was also modified by tungstate in a leptin-dependent manner. In summary, the results indicate that the effectiveness of tungstate in reducing body weight gain is completely dependent on a functional leptin system.

  11. Acrylonitrile characterization and high energetic photochemistry at Titan temperatures

    NASA Astrophysics Data System (ADS)

    Toumi, A.; Piétri, N.; Chiavassa, T.; Couturier-Tamburelli, I.

    2016-05-01

    Laboratory infrared spectra of amorphous and crystalline acrylonitrile (C2H3CN) ices were recorded between 4000 and 650 cm-1. Heating up the acrylonitrile sample to 160 K shows details on the transition between amorphous and crystalline ice at ∼94 K. This molecule can be used as an indicator of the surface temperature of Titan since it is known also to be ∼94 K. The desorption energy of acrylonitrile was determined using two methods (IRTF and mass spectrometries) to be around 35 kJ mol-1. Solid phase acrylonitrile was irradiated with vacuum ultraviolet (VUV) light at low temperatures (20, 70, 95 and 130 K) using a microwave-discharge hydrogen flow lamp. Isoacrylonitrile, cyanoacetylene (HC3N), isocyanoacetylene (HC2NC), acetylene (C2H2) and hydrogen cyanide (HCN) were identified as photoproducts by using FTIR spectroscopy. The branching ratio of each pathway has been calculated for the different temperatures. We have estimated the acrylonitrile, HCN and HC3N νCtbnd N stretching band strengths to be respectively A = 3.98 ×10-18 , A = 1.38 ×10-18 and A = 2.92 ×10-18cmmolecule-1 .

  12. Molecular mechanisms of tungstate-induced pancreatic plasticity: a transcriptomics approach

    PubMed Central

    Altirriba, Jordi; Barbera, Albert; Del Zotto, Héctor; Nadal, Belen; Piquer, Sandra; Sánchez-Pla, Alex; Gagliardino, Juan J; Gomis, Ramon

    2009-01-01

    Background Sodium tungstate is known to be an effective anti-diabetic agent, able to increase beta cell mass in animal models of diabetes, although the molecular mechanisms of this treatment and the genes that control pancreas plasticity are yet to be identified. Using a transcriptomics approach, the aim of the study is to unravel the molecular mechanisms which participate in the recovery of exocrine and endocrine function of streptozotocin (STZ) diabetic rats treated with tungstate, determining the hyperglycemia contribution and the direct effect of tungstate. Results Streptozotocin (STZ)-diabetic rats were treated orally with tungstate for five weeks. Treated (STZ)-diabetic rats showed a partial recovery of exocrine and endocrine function, with lower glycemia, increased insulinemia and amylasemia, and increased beta cell mass achieved by reducing beta cell apoptosis and raising beta cell proliferation. The microarray analysis of the pancreases led to the identification of three groups of differentially expressed genes: genes altered due to diabetes, genes restored by the treatment, and genes specifically induced by tungstate in the diabetic animals. The results were corroborated by quantitative PCR. A detailed description of the pathways involved in the pancreatic effects of tungstate is provided in this paper. Hyperglycemia contribution was studied in STZ-diabetic rats treated with phloridzin, and the direct effect of tungstate was determined in INS-1E cells treated with tungstate or serum from untreated or treated STZ-rats, observing that tungstate action in the pancreas takes places via hyperglycemia-independent pathways and via a combination of tungstate direct and indirect (through the serum profile modification) effects. Finally, the MAPK pathway was evaluated, observing that it has a key role in the tungstate-induced increase of beta cell proliferation as tungstate activates the mitogen-activated protein kinase (MAPK) pathway directly by increasing p42/p44

  13. 21 CFR 177.1480 - Nitrile rubber modified acrylonitrile-methyl acrylate copolymers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Nitrile rubber modified acrylonitrile-methyl... Components of Single and Repeated Use Food Contact Surfaces § 177.1480 Nitrile rubber modified acrylonitrile-methyl acrylate copolymers. Nitrile rubber modified acrylonitrile-methyl acrylate copolymers...

  14. A study on the properties of lead tungstate crystals

    NASA Astrophysics Data System (ADS)

    Y. Zhu, R.; Ma, D. A.; Newman, H. B.; Woody, C. L.; Kierstead, J. A.; Stoll, S. P.; Levy, P. W.

    1996-07-01

    This report summarizes the results of a study on the properties of five large and five small size lead tungstate (PbWO4) crystals. Data are presented on the longitudinal optical transmittance and light attenuation length, light yield and response uniformity, emission spectra and decay time. The radiation resistance of large crystals and possible curing with optical bleaching are discussed. The result of an in depth materials study, including trace impurities analysis, are also presented. The general conclusion from this investigation is that further research and development is needed to develop fast, radiation-hard PbWO4 crystals for the CMS experiment at the CERN LHC.

  15. The magnetic properties of potassium holmium double tungstate

    NASA Astrophysics Data System (ADS)

    Borowiec, M. T.; Dyakonov, V. P.; Khatsko, E. N.; Zayarnyuk, T.; Zubov, E. E.; Szewczyk, A.; Gutowska, M. U.; Rykova, A. I.; Pietosa, J.; Majchrowski, A.; Michalski, E.; Hoffmann, J.-U.; Prokes, K.; Woźniak, K.; Dobrzycki, Ł.; Barański, M.; Domukhovski, V.; Shtyrkhunova, V.; Żmija, J.; Szymczak, H.

    2011-08-01

    The magnetic investigations of potassium holmium double tungstate KHo(WO4)2 have been performed. The results of measurements of magnetic susceptibility and magnetization as a function of temperature (T from 0.3 K up to 100 K) and magnetic field (up to 1.5 T) are presented. A strong anisotropy of magnetic properties was found. The magnetic measurements data were used to calculate the interaction energy. It was shown that the interactions between nearest neighbors Ho3+ ions have antiferromagnetic character.

  16. Optical and dielectric studies on tin(iv) tungstate nanoparticles

    NASA Astrophysics Data System (ADS)

    B, Beena; S, Manoj

    2015-02-01

    Tin(IV) tungstate nanoparticles in the form of disc were synthesized by a novel chemical coprecipitation method. Surface morphology and particle size of the synthesized materials were analysed using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). SEM image shows disc like appearance of the nanoparticles. The particle size obtained was found to be ~20nm. Optical absorption for this material arises due to O2p → W5d charge transfer in the tungstate structure. The energy band gap determined using optical absorption spectrum shows that it is a direct band gap semiconductor. The extent of disorder determined using Urbach plot was found to be 0.00176 meV. The material showed intrinsic Photoluminescence around 468nm when excited by UV light of 275nm. The variation of dielectric permittivity in the frequency range 316 Hz to 3.16 MHz was studied. The temperature dependence of dielectric permittivity was also studied in the frequency range 10Hz and 32 MHz. The compound exhibit a high dielectric constant at room temperature (ε1>103) for frequencies 10Hz and (ε1 > 105) for frequencies 3.2×107 Hz. It posses lower dielectric loss ie, ~0.1 at 10 Hz to ~3 at 3.2×107 Hz. The material is very attractive for potential application provides its losses can be minimized.

  17. Toxicity of sodium tungstate to earthworm, oat, radish, and lettuce.

    PubMed

    Bamford, Josie E; Butler, Alicia D; Heim, Katherine E; Pittinger, Charles A; Lemus, Ranulfo; Staveley, Jane P; Lee, K Brian; Venezia, Carmen; Pardus, Michael J

    2011-10-01

    Due to unknown effects of the potential exposure of the terrestrial environment to tungsten substances, a series of toxicity studies of sodium tungstate (Na(2) WO(4) ) was conducted. The effect on earthworm (Eisenia fetida) survival and reproduction was examined using Organisation for Economic Co-operation and Development (OECD) Guideline 222. No effect on either endpoint was seen at the highest concentration tested, resulting in a 56-d no-observed-effect concentration (NOEC) of ≥586 mg tungsten/kg dry soil (nominal concentrations). The effect of sodium tungstate on emergence and growth of plant species was examined according to OECD Guideline 208: oat (Avena sativa), radish (Raphanus sativus), and lettuce (Lactuca sativa). No effects on emergence, shoot height, and dry shoot weight were observed in oats exposed to the highest concentration, resulting in a 21-d NOEC of ≥586 mg tungsten/kg dry soil. The NOECs for radish and lettuce were 65 and 21.7 mg tungsten/kg dry soil (nominal concentrations), respectively. Respective 21-d median effective concentration values (EC50) for radish and lettuce were >586 and 313 mg tungsten/kg dry soil (based on shoot height) (confidence level [CL] -8.5-615); EC25 values were 152 (CL 0-331) and 55 (CL 0-114) mg tungsten/kg dry soil. Results are consistent with the few other tungsten substance terrestrial toxicity studies in the literature.

  18. Femtosecond laser ablation of cadmium tungstate for scintillator arrays

    NASA Astrophysics Data System (ADS)

    Richards, S.; Baker, M. A.; Wilson, M. D.; Lohstroh, A.; Seller, P.

    2016-08-01

    Ultrafast pulsed laser ablation has been investigated as a technique to machine CdWO4 single crystal scintillator and segment it into small blocks with the aim of fabricating a 2D high energy X-ray imaging array. Cadmium tungstate (CdWO4) is a brittle transparent scintillator used for the detection of high energy X-rays and γ-rays. A 6 W Yb:KGW Pharos-SP pulsed laser of wavelength 1028 nm was used with a tuneable pulse duration of 10 ps to 190 fs, repetition rate of up to 600 kHz and pulse energies of up to 1 mJ was employed. The effect of varying the pulse duration, pulse energy, pulse overlap and scan pattern on the laser induced damage to the crystals was investigated. A pulse duration of ≥500 fs was found to induce substantial cracking in the material. The laser induced damage was minimised using the following operating parameters: a pulse duration of 190 fs, fluence of 15.3 J cm-2 and employing a serpentine scan pattern with a normalised pulse overlap of 0.8. The surface of the ablated surfaces was studied using scanning electron microscopy, energy dispersive X-ray spectroscopy, atomic force microscopy and X-ray photoelectron spectroscopy. Ablation products were found to contain cadmium tungstate together with different cadmium and tungsten oxides. These laser ablation products could be removed using an ammonium hydroxide treatment.

  19. 21 CFR 181.32 - Acrylonitrile copolymers and resins.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Acrylonitrile copolymers and resins. 181.32 Section 181.32 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) PRIOR-SANCTIONED FOOD INGREDIENTS Specific Prior-Sanctioned Food Ingredients §...

  20. IRIS Toxicological Review of Acrylonitrile (Interagency Science Consultation Draft)

    EPA Science Inventory

    On June 30, 2011, the draft Toxicological Review of Acrylonitrile and the charge to external peer reviewers were released for external peer review and public comment. The Toxicological Review and charge were reviewed internally by EPA and by other federal agencies and White House...

  1. Theoretical calculations of emission of wolframite and scheelite-type tungstate crystals

    SciTech Connect

    Nikolaenko, T.; Hizhnyi, Y.; Nedilko, S.

    2009-01-21

    Tungstate crystals AWO{sub 4} (A = Zn,Cd,Pb) are well-known scintillation materials for various applications in science and technology. In recent years the optical properties of these crystals were intensively studied experimentally and theoretically. However, the origin of luminescence in lead, cadmium and zinc tungstates is still the subject of discussion. According to generally accepted view, the centers of luminescence in AWO{sub 4} crystals are in some or other way related to the tungstate anionic groups. We developed a cluster approach in theoretical investigation of the electronic structure of AWO{sub 4} tungstate crystals based on the configuration interaction (CI) computation in which the lattice vibrations were taken into account.

  2. Large-scale synthesis and photoluminescence of cobalt tungstate nanowires

    NASA Astrophysics Data System (ADS)

    Zhang, Cuiling; Guo, Donglin; Hu, Chenguo; Chen, Yanxue; Liu, Hong; Zhang, Hulin; Wang, Xue

    2013-01-01

    Single-crystalline wolframite-type monoclinic structure cobalt tungstate (CoWO4) nanowires were obtained by a solvothermal method at 180 °C for 24 h with a width of 20 nm and length of 200 to 400 nm. Besides the strong blue-green light emission at 10-250 K, we found much stronger and broader near-infrared emission ranging from 700-1000 nm at about 300 K under the excitation wavelength of 325 nm. The emission and the dependence of emission intensity on temperature are discussed by introducing the effect of Co vacancies. This near-infrared emission material might have potential applications in infrared detection or stealth technology.

  3. The specific heat of potassium holmium double tungstate

    NASA Astrophysics Data System (ADS)

    Borowiec, M. T.; Dyakonov, V. P.; Szewczyk, A.; Gutowska, M. U.; Zayarnyuk, T.; Zubov, E. E.; Majchrowski, A.; Michalski, E.; Hoffmann, J.-U.; Prokes, K.; Woźniak, K.; Dobrzycki, Ł.; Khatsko, E. N.; Rykova, A. I.; Domukhovski, V.; Barański, M.; Shtyrkhunova, V.; Żmija, J.; Szymczak, H.

    2011-11-01

    The results of measurements of thermal properties (specific heat) of potassium holmium double tungstate KHo(WO4)2 as a function of temperature (from 0.5 to 300 K) and magnetic field (up to 2 T) are presented. The total specific heat without the phonon and Schottky contributions is found to have the anomaly with maximum at T SPT ∼ 5 K. This anomaly is likely related with the structural phase transition (SPT) caused by the cooperative Jahn-Teller effect. The increase of specific heat at very low temperatures and its shift towards high temperatures with increasing magnetic field are observed. The origin of this behaviour can be connected with possible magnetic phase transition induced by magnetic field.

  4. Optical properties of doped potassium gadolinium tungstate single crystals

    NASA Astrophysics Data System (ADS)

    Michalski, E.; Zmija, Jozef; Mierczyk, Zygmunt; Majchrowski, Andrzej; Kopczynski, Krzysztof; Cichowski, S.; Wojtanowski, J.

    2001-08-01

    Single crystals of double tungstates find applications as laser materials having very good parameters. One of the intensively investigated material sis KGD(WO4)2 doped with rare earth elements. Single crystal of KGd(WO4)2 were grown with the use of Top Seeded Solution Growth technique from K2W2O7 solvent. The crystals have low absorption loses and show high lasing efficiency. Optical investigations of as grown KGW:Nd single crystal confirmed their good optical quality and high absorption coefficient near 810 nm, what in connection with strong luminescence near 1067 nm allows fabrication of diode pumped microchip lasers working both in CW and giant pulse regime. Absorption and luminescence spectra of Nd3+ doped KGW single crystals are presented. Laser action was obtained in form of 128.5 kHz train of 100 ns giant pluses due to YAG:Cr4+ passive Q-switch.

  5. 40 CFR 721.9840 - Tungstate (W12(OH)2O386-) hexasodium (9CI).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...(OH)2O386-) hexasodium (9CI) (PMN P-96-1177; CAS No. 12141-67-2) is subject to reporting under this... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Tungstate (W12(OH)2O386-) hexasodium... Specific Chemical Substances § 721.9840 Tungstate (W12(OH)2O386-) hexasodium (9CI). (a) Chemical...

  6. 40 CFR 721.9840 - Tungstate (W12(OH)2O386-) hexasodium (9CI).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...(OH)2O386-) hexasodium (9CI) (PMN P-96-1177; CAS No. 12141-67-2) is subject to reporting under this... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Tungstate (W12(OH)2O386-) hexasodium... Specific Chemical Substances § 721.9840 Tungstate (W12(OH)2O386-) hexasodium (9CI). (a) Chemical...

  7. 40 CFR 721.9840 - Tungstate (W12(OH)2O386-) hexasodium (9CI).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...(OH)2O386-) hexasodium (9CI) (PMN P-96-1177; CAS No. 12141-67-2) is subject to reporting under this... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Tungstate (W12(OH)2O386-) hexasodium... Specific Chemical Substances § 721.9840 Tungstate (W12(OH)2O386-) hexasodium (9CI). (a) Chemical...

  8. 40 CFR 721.9840 - Tungstate (W12(OH)2O386-) hexasodium (9CI).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...(OH)2O386-) hexasodium (9CI) (PMN P-96-1177; CAS No. 12141-67-2) is subject to reporting under this... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Tungstate (W12(OH)2O386-) hexasodium... Specific Chemical Substances § 721.9840 Tungstate (W12(OH)2O386-) hexasodium (9CI). (a) Chemical...

  9. 40 CFR 721.9840 - Tungstate (W12(OH)2O386-) hexasodium (9CI).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...(OH)2O386-) hexasodium (9CI) (PMN P-96-1177; CAS No. 12141-67-2) is subject to reporting under this... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Tungstate (W12(OH)2O386-) hexasodium... Specific Chemical Substances § 721.9840 Tungstate (W12(OH)2O386-) hexasodium (9CI). (a) Chemical...

  10. Effect of sodium tungstate on visual evoked potentials in diabetic rats

    PubMed Central

    Bulut, Mehmet; Dönmez, Barış Özgür; Öztürk, Nihal; Başaranlar, Göksun; Kencebay Manas, Ceren; Derin, Narin; Özdemir, Semir

    2016-01-01

    AIM To evaluate the effect of sodium tungstate on visual evoked potentials (VEPs) in diabetic rats. METHODS Wistar rats were randomly divided into three groups as normal control, diabetic control and diabetic rats treated with sodium tungstate. Diabetes was induced by single intraperitoneal injection of streptozotocin (50 mg/kg). Sodium tungstate [40 mg/(kg·d)] was administered for 12wk and then VEPs were recorded. Additionally, thiobarbituric acid reactive substance (TBARS) levels were measured in brain tissues. RESULTS The latencies of P1, N1, P2, N2 and P3 waves were significantly prolonged in diabetic rats compared with control group. Diabetes mellitus caused an increase in the lipid peroxidation process that was accompanied by changes in VEPs. However, prolonged latencies of VEPs for all components returned to control levels in sodium tungstate-treated group. The treatment of sodium tungstate significantly decreased brain TBARS levels and depleted the prolonged latencies of VEP components compared with diabetic control group. CONCLUSION Sodium tungstate shows protective effects on visual pathway in diabetic rats, and it can be worthy of further study for potential use. PMID:27275420

  11. Phosphorylation events implicating p38 and PI3K mediate tungstate-effects in MIN6 beta cells

    SciTech Connect

    Piquer, Sandra; Gomis, Ramon . E-mail: rgomis@clinic.ub.es

    2007-06-29

    Oral administration of sodium tungstate is an effective treatment for diabetes in animal models. Several lines of evidence indicate the pancreatic beta cell as one of the targets of tungstate action. Here, we examined the molecular mechanism by which this compound exerts its effects on the beta cell line MIN6. Tungstate treatment induced phosphorylation and subsequent activation of p38 and PI3K which in turn are implicated in tungstate PDX-1 nuclear localization and activation. Although no effect was observed in glucose-induced insulin secretion we found that tungstate activates basal insulin release, a process driven, at least in part, by activation of p38. These results show a direct involvement of p38 and PI3K phosphorylation in the mechanism of action of tungstate in the beta cell.

  12. Radiation initiated copolymerization of allyl alcohol with acrylonitrile

    NASA Astrophysics Data System (ADS)

    Şolpan, Dilek; Güven, Olgun

    1996-07-01

    Copolymerization of allyl alcohol (AA) with acrylonitrile (AN) initiated by γ-rays has been investigated to determine the respective reactivity ratios. Three different experimental techniques, namely Fourier Transform Infrared (FTIR), Ultraviolet (UV/vis) and elemental analysis (EA) have been used for the determination of copolymer compositions. Fineman-Ross (FR), Kelen-Tüdös (KT), Non-Linear Least Square (NLLS) Analysis and Q-e methods have been applied to the three sets of experimental data. It has been concluded that data obtained from elemental analysis as applied to the Non-Linear Least Square approach gave the most reliable reactivity ratios as 2.09 and 0.40 for acrylonitrile and allyl alcohol, respectively.

  13. Tungstate-Targeting of BKαβ1 Channels Tunes ERK Phosphorylation and Cell Proliferation in Human Vascular Smooth Muscle

    PubMed Central

    Fernández-Mariño, Ana Isabel; Cidad, Pilar; Zafra, Delia; Nocito, Laura; Domínguez, Jorge; Oliván-Viguera, Aida; Köhler, Ralf; López-López, José R.; Pérez-García, María Teresa; Valverde, Miguel Ángel; Guinovart, Joan J.; Fernández-Fernández, José M.

    2015-01-01

    Despite the substantial knowledge on the antidiabetic, antiobesity and antihypertensive actions of tungstate, information on its primary target/s is scarce. Tungstate activates both the ERK1/2 pathway and the vascular voltage- and Ca2+-dependent large-conductance BKαβ1 potassium channel, which modulates vascular smooth muscle cell (VSMC) proliferation and function, respectively. Here, we have assessed the possible involvement of BKαβ1 channels in the tungstate-induced ERK phosphorylation and its relevance for VSMC proliferation. Western blot analysis in HEK cell lines showed that expression of vascular BKαβ1 channels potentiates the tungstate-induced ERK1/2 phosphorylation in a Gi/o protein-dependent manner. Tungstate activated BKαβ1 channels upstream of G proteins as channel activation was not altered by the inhibition of G proteins with GDPβS or pertussis toxin. Moreover, analysis of Gi/o protein activation measuring the FRET among heterologously expressed Gi protein subunits suggested that tungstate-targeting of BKαβ1 channels promotes G protein activation. Single channel recordings on VSMCs from wild-type and β1-knockout mice indicated that the presence of the regulatory β1 subunit was essential for the tungstate-mediated activation of BK channels in VSMCs. Moreover, the specific BK channel blocker iberiotoxin lowered tungstate-induced ERK phosphorylation by 55% and partially reverted (by 51%) the tungstate-produced reduction of platelet-derived growth factor (PDGF)-induced proliferation in human VSMCs. Our observations indicate that tungstate-targeting of BKαβ1 channels promotes activation of PTX-sensitive Gi proteins to enhance the tungstate-induced phosphorylation of ERK, and inhibits PDGF-stimulated cell proliferation in human vascular smooth muscle. PMID:25659150

  14. Amorphous tungstate precursor route to nanostructured tungsten oxide film with electrochromic property.

    PubMed

    Jeon, Ie-Rang; Kang, Joo-Hee; Paek, Seung-Min; Hwang, Seong-Ju; Choy, Jin-Ho

    2011-07-01

    Electrochromic tungsten oxide (WO3) films on ITO glass were fabricated by spin-coating with a tungsten peroxy acid solution, which was prepared by adding an equivolume mixture of hydrogen peroxide and glacial acetic acid to tungsten metal powder. The structural evolution of the tungstate precursor upon heat treatment was studied by X-ray diffraction (XRD) and X-ray absorption near edge structure (XANES) analyses, which indicated that the as-synthesized tungstate transformed into nanocrystalline WO3 upon heating. It is, therefore, quite clear that as-synthesized tungstate can be a good precursor for electrochromic WO3 films. A series of WO3 thin films were prepared on ITO glass by spin-coating with different concentrations of tungsten peroxy acid solution and then post-annealing at various temperatures. Depending on the concentration of the tungstate coating solution (200-500 mg mL(-1)) and the annealing temperature (100-300 degrees C), the thickness and WO3 content as well as the electrochromic properties of WO3 films can be controlled. As a result, the optimum fabrication conditions were determined to be a tungstate solution concentration of 300-400 mg mL(-1) and a post-annealing temperature of 200 degrees C. Finally, an inorganic-inorganic hybrid electrochromic device (ECD) composed of optimized WO3 and Prussian Blue (PB) with desirable coloration efficiency was successfully developed. PMID:22121748

  15. Synthesis and Characterization of Zirconium Tungstate Ultra-Thin Fibers

    SciTech Connect

    Zhang, Lifeng; Howe, Jane Y; Fong, Hao; Zhang, Yan

    2009-01-01

    This study reports an innovative method of electrospinning followed by pyrolysis to synthesize zirconium tungstate (ZrW2O8), a material with negative coefficient of thermal expansion (CTE), in ultra-thin fiber form. Morphologies and microstructures of the as-electrospun precursor fibers, the heat-treated intermediate fibers, and the final ZrW2O8 ultra-thin fibers were characterized by SEM, XRD, and TEM. The ZrW2O8 ultra-thin fibers had diameters in the sub-micrometer range with aspect ratios larger than 100; these fibers were polycrystalline, and consisted of single crystalline ZrW2O8 crystallites with sizes of 30-50 nm and surface roughness of several nanometers. The ZrW2O8 ultra-thin fibers are expected to outperform spherically, cylindrically, and/or irregularly shaped polycrystalline ZrW2O8 particles for the development of composites with precisely controlled CTEs. Additionally, this reported method could be utilized as a general approach to convert nano-scaled inorganic particles into fibers.

  16. 21 CFR 177.1020 - Acrylonitrile/butadiene/sty-rene co-polymer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Acrylonitrile/butadiene/sty-rene co-polymer. 177... SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances.../butadiene/sty-rene co-polymer. Acrylonitrile/butadiene/styrene copolymer identified in this section may...

  17. 21 CFR 177.1020 - Acrylonitrile/butadiene/sty-rene co-polymer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Acrylonitrile/butadiene/sty-rene co-polymer. 177... SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances.../butadiene/sty-rene co-polymer. Acrylonitrile/butadiene/styrene copolymer identified in this section may...

  18. 21 CFR 177.1020 - Acrylonitrile/butadiene/sty-rene co-polymer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Acrylonitrile/butadiene/sty-rene co-polymer. 177... SERVICES (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1020 Acrylonitrile/butadiene/sty-rene co-polymer....

  19. 76 FR 77267 - Acrylonitrile Standard; Extension of the Office of Management and Budget's (OMB) Approval of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-12

    ... Acrylonitrile (AN) Standard protect workers from the adverse health effects that may result from their exposure... approved collection. Title: Acrylonitrile Standard (29 CFR 1910.1045). OMB Control Number: 1218-0126... submitting personal information, such as Social Security numbers and dates of birth. Although all...

  20. 21 CFR 177.1030 - Acrylonitrile/butadiene/styrene/methyl methacrylate copolymer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... as determined by a method titled “Analysis of Cycopac Resin for Residual β-(2-Hydroxyethylmercapto... the range of 13.0 to 16.0 percent as determined by Micro-Kjeldahl analysis. (2) Residual acrylonitrile... a gas chromatographic method titled “Determination of Residual Acrylonitrile and Styrene...

  1. 21 CFR 177.1020 - Acrylonitrile/butadiene/sty-rene co-polymer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Acrylonitrile/butadiene/sty-rene co-polymer. 177... SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances.../butadiene/sty-rene co-polymer. Acrylonitrile/butadiene/styrene copolymer identified in this section may...

  2. 21 CFR 177.1020 - Acrylonitrile/butadiene/sty-rene co-polymer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Acrylonitrile/butadiene/sty-rene co-polymer. 177... SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances.../butadiene/sty-rene co-polymer. Acrylonitrile/butadiene/styrene copolymer identified in this section may...

  3. 21 CFR 177.1040 - Acrylonitrile/styrene copoly-mer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... temperature for 2 h.1 Minimum 10 pct solution viscosity at 25 °C (77 °F) is 10cP. 1 3. Acrylonitrile/styrene... average molecular weight, and solution viscosity, titled: “Determination of Residual Acrylonitrile and Styrene Monomers-Gas Chromatographic Internal Standard Method”; “Infrared Spectrophotometric...

  4. 21 CFR 177.1040 - Acrylonitrile/styrene copoly-mer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... temperature for 2 h.1 Minimum 10 pct solution viscosity at 25 °C (77 °F) is 10cP. 1 3. Acrylonitrile/styrene... average molecular weight, and solution viscosity, titled: “Determination of Residual Acrylonitrile and Styrene Monomers-Gas Chromatographic Internal Standard Method”; “Infrared Spectrophotometric...

  5. Kinetic and equilibrium studies of acrylonitrile binding to cytochrome c peroxidase and oxidation of acrylonitrile by cytochrome c peroxidase compound I

    SciTech Connect

    Chinchilla, Diana Kilheeney, Heather Vitello, Lidia B. Erman, James E.

    2014-01-03

    Highlights: •Cytochrome c peroxidase (CcP) binds acrylonitrile in a pH-independent fashion. •The spectrum of the CcP/acrylonitrile complex is that of a 6c–ls ferric heme. •The acrylonitrile/CcP complex has a K{sub D} value of 1.1 ± 0.2 M. •CcP compound I oxidizes acrylonitrile with a maximum turnover rate of 0.61 min{sup −1}. -- Abstract: Ferric heme proteins bind weakly basic ligands and the binding affinity is often pH dependent due to protonation of the ligand as well as the protein. In an effort to find a small, neutral ligand without significant acid/base properties to probe ligand binding reactions in ferric heme proteins we were led to consider the organonitriles. Although organonitriles are known to bind to transition metals, we have been unable to find any prior studies of nitrile binding to heme proteins. In this communication we report on the equilibrium and kinetic properties of acrylonitrile binding to cytochrome c peroxidase (CcP) as well as the oxidation of acrylonitrile by CcP compound I. Acrylonitrile binding to CcP is independent of pH between pH 4 and 8. The association and dissociation rate constants are 0.32 ± 0.16 M{sup −1} s{sup −1} and 0.34 ± 0.15 s{sup −1}, respectively, and the independently measured equilibrium dissociation constant for the complex is 1.1 ± 0.2 M. We have demonstrated for the first time that acrylonitrile can bind to a ferric heme protein. The binding mechanism appears to be a simple, one-step association of the ligand with the heme iron. We have also demonstrated that CcP can catalyze the oxidation of acrylonitrile, most likely to 2-cyanoethylene oxide in a “peroxygenase”-type reaction, with rates that are similar to rat liver microsomal cytochrome P450-catalyzed oxidation of acrylonitrile in the monooxygenase reaction. CcP compound I oxidizes acrylonitrile with a maximum turnover number of 0.61 min{sup −1} at pH 6.0.

  6. Vibrations of acrylonitrile in N 1s excited states

    NASA Astrophysics Data System (ADS)

    Ilakovac, V.; Carniato, S.; Gallet, J.-J.; Kukk, E.; Horvatić, D.; Ilakovac, A.

    2008-01-01

    The N 1s near edge x-ray absorption fine structure spectra of acrylonitrile gas are accurately reproduced by a complete ab initio multidimensional vibrational analysis. The role of π∗ -orbital localization and hybridization on vibrations accompanying core excitation is discussed. Transition to the π⊥∗(C=C-C≡N) delocalized orbital excites mostly stretching vibrations of the whole spinal column of the molecule. Promoting a core electron to the localized π∥∗(C≡N) produces C≡N stretching vibration combined with two strong bending modes of the C-C≡N end of the molecule, related to the change of carbon hybridization.

  7. Kinetic and equilibrium studies of acrylonitrile binding to cytochrome c peroxidase and oxidation of acrylonitrile by cytochrome c peroxidase compound I.

    PubMed

    Chinchilla, Diana; Kilheeney, Heather; Vitello, Lidia B; Erman, James E

    2014-01-01

    Ferric heme proteins bind weakly basic ligands and the binding affinity is often pH dependent due to protonation of the ligand as well as the protein. In an effort to find a small, neutral ligand without significant acid/base properties to probe ligand binding reactions in ferric heme proteins we were led to consider the organonitriles. Although organonitriles are known to bind to transition metals, we have been unable to find any prior studies of nitrile binding to heme proteins. In this communication we report on the equilibrium and kinetic properties of acrylonitrile binding to cytochrome c peroxidase (CcP) as well as the oxidation of acrylonitrile by CcP compound I. Acrylonitrile binding to CcP is independent of pH between pH 4 and 8. The association and dissociation rate constants are 0.32±0.16 M(-1) s(-1) and 0.34±0.15 s(-1), respectively, and the independently measured equilibrium dissociation constant for the complex is 1.1±0.2 M. We have demonstrated for the first time that acrylonitrile can bind to a ferric heme protein. The binding mechanism appears to be a simple, one-step association of the ligand with the heme iron. We have also demonstrated that CcP can catalyze the oxidation of acrylonitrile, most likely to 2-cyanoethylene oxide in a "peroxygenase"-type reaction, with rates that are similar to rat liver microsomal cytochrome P450-catalyzed oxidation of acrylonitrile in the monooxygenase reaction. CcP compound I oxidizes acrylonitrile with a maximum turnover number of 0.61 min(-1) at pH 6.0. PMID:24291498

  8. Kinetic and equilibrium studies of acrylonitrile binding to cytochrome c peroxidase and oxidation of acrylonitrile by cytochrome c peroxidase compound I

    PubMed Central

    Chinchilla, Diana; Kilheeney, Heather; Vitello, Lidia B.; Erman, James E.

    2013-01-01

    Ferric heme proteins bind weakly basic ligands and the binding affinity is often pH dependent due to protonation of the ligand as well as the protein. In an effort to find a small, neutral ligand without significant acid/base properties to probe ligand binding reactions in ferric heme proteins we were led to consider the organonitriles. Although organonitriles are known to bind to transition metals, we have been unable to find any prior studies of nitrile binding to heme proteins. In this communication we report on the equilibrium and kinetic properties of acrylonitrile binding to cytochrome c peroxidase (CcP) as well as the oxidation of acrylonitrile by CcP compound I. Acrylonitrile binding to CcP is independent of pH between pH 4 and 8. The association and dissociation rate constants are 0.32 ± 0.16 M−1s−1 and 0.34 ± 0.15 s−1, respectively, and the independently measured equilibrium dissociation constant for the complex is 1.1 ± 0.2 M. We have demonstrated for the first time that acrylonitrile can bind to a ferric heme protein. The binding mechanism appears to be a simple, one-step association of the ligand with the heme iron. We have also demonstrated that CcP can catalyze the oxidation of acrylonitrile, most likely to 2-cyanoethylene oxide in a “peroxygenase”-type reaction, with rates that are similar to rat liver microsomal cytochrome P450-catalyzed oxidation of acrylonitrile in the monooxygenase reaction. CcP compound I oxidizes acrylonitrile with a maximum turnover number of 0.61 min−1 at pH 6.0. PMID:24291498

  9. Kinetic and equilibrium studies of acrylonitrile binding to cytochrome c peroxidase and oxidation of acrylonitrile by cytochrome c peroxidase compound I.

    PubMed

    Chinchilla, Diana; Kilheeney, Heather; Vitello, Lidia B; Erman, James E

    2014-01-01

    Ferric heme proteins bind weakly basic ligands and the binding affinity is often pH dependent due to protonation of the ligand as well as the protein. In an effort to find a small, neutral ligand without significant acid/base properties to probe ligand binding reactions in ferric heme proteins we were led to consider the organonitriles. Although organonitriles are known to bind to transition metals, we have been unable to find any prior studies of nitrile binding to heme proteins. In this communication we report on the equilibrium and kinetic properties of acrylonitrile binding to cytochrome c peroxidase (CcP) as well as the oxidation of acrylonitrile by CcP compound I. Acrylonitrile binding to CcP is independent of pH between pH 4 and 8. The association and dissociation rate constants are 0.32±0.16 M(-1) s(-1) and 0.34±0.15 s(-1), respectively, and the independently measured equilibrium dissociation constant for the complex is 1.1±0.2 M. We have demonstrated for the first time that acrylonitrile can bind to a ferric heme protein. The binding mechanism appears to be a simple, one-step association of the ligand with the heme iron. We have also demonstrated that CcP can catalyze the oxidation of acrylonitrile, most likely to 2-cyanoethylene oxide in a "peroxygenase"-type reaction, with rates that are similar to rat liver microsomal cytochrome P450-catalyzed oxidation of acrylonitrile in the monooxygenase reaction. CcP compound I oxidizes acrylonitrile with a maximum turnover number of 0.61 min(-1) at pH 6.0.

  10. The effects of tungstate on skin lesions caused by PPD in rats.

    PubMed

    Lee, Sang-Hee; Cho, Hyun-Gug; Lee, Sang-Il

    2008-04-01

    P-phenylenediamine (PPD) has been used as one of the ingredients in hair dye. The purpose of this study is to investigate the skin toxicity of PPD application in a tungstate-induced xanthine oxidase (XO) deficient animal model. PPD (2.5% PPD in 2% NH4OH) was applied to rat skin (25 mg/16.5 cm2) five times every other day in rats fed a standard diet (SD) or a tungstate supplemented diet (TD). The skin structure in the SD and the TD group was intact, whereas XO activity was not detected in the TD group during experimental periods. Furthermore, there were no differences between the SD and the TD group in dermal reactive oxygen species (ROS) scavenging enzymes. In these experimental conditions, although XO activity was not detected in the applied PPD rats fed a tungstate supplemented diet (PTD) group, it showed more severe tissue damage compared with the applied PPD rats fed a standard diet (PSD) group. In addition, the PTD group showed higher increased rates of ROS scavenging enzyme activity and lipid peroxide (LPO) content, and decreased glutathione (GSH) content than in the PSD group. In conclusion, the increase of PPD dermal toxicity in tungstate-induced XO deficient animals may be due to excessive ROS via ROS imbalance during PPD skin application. PMID:18379062

  11. Zirconium tungstate hydroxide hydrate revisited: Crystallization dependence on halide and hydronium ions

    SciTech Connect

    Colin, Julie A. Camper, DeMarco V.; Gates, Stacy D.; Simon, Monty D. Witker, Karen L. Lind, Cora

    2007-12-15

    The formation of zirconium tungstate hydroxide hydrate, a precursor to the negative thermal expansion material cubic zirconium tungstate, shows a strong dependence on hydrothermal reaction conditions. It was found that not only the acid concentration, but also the acid counterion plays a significant role in the crystallization of ZrW{sub 2}O{sub 7}(OH){sub 2}.2H{sub 2}O. High temperatures, high acid concentrations, and the presence of chloride or bromide ions promote the formation of well-crystallized ZrW{sub 2}O{sub 7}(OH){sub 2}.2H{sub 2}O. For low acid concentrations, a new zirconium tungstate hydrate polymorph is observed, which transforms to tetragonal ZrW{sub 2}O{sub 7}(OH){sub 2}.2H{sub 2}O at longer reaction times. A study of crystallization kinetics in hydrochloric acid is presented. - Graphical abstract: The formation of ZrW{sub 2}O{sub 7}(OH){sub 2}.2H{sub 2}O shows a strong dependence on reaction conditions. Both acid concentration and acid counterion play a significant role in the crystallization. High temperatures, high acid concentrations, and the presence of chloride or bromide ions promote the formation of well-crystallized ZrW{sub 2}O{sub 7}(OH){sub 2}.2H{sub 2}O. For low acid concentrations, a new zirconium tungstate hydrate polymorph is observed.

  12. In vivo comet assay of acrylonitrile, 9-aminoacridine hydrochloride monohydrate and ethanol in rats.

    PubMed

    Nakagawa, Yuzuki; Toyoizumi, Tomoyasu; Sui, Hajime; Ohta, Ryo; Kumagai, Fumiaki; Usumi, Kenji; Saito, Yoshiaki; Yamakage, Kohji

    2015-07-01

    As part of the Japanese Center for the Validation of Alternative Methods (JaCVAM)-initiative international validation study of the in vivo rat alkaline comet assay, we examined the ability of acrylonitrile, 9-aminoacridine hydrochloride monohydrate (9-AA), and ethanol to induce DNA damage in the liver and glandular stomach of male rats. Acrylonitrile is a genotoxic carcinogen, 9-AA is a genotoxic non-carcinogen, and ethanol is a non-genotoxic carcinogen. Positive results were obtained in the liver cells of male rats treated with known genotoxic compounds, acrylonitrile and 9-AA.

  13. Radical-initiated controlled synthesis of homo- and copolymers based on acrylonitrile

    NASA Astrophysics Data System (ADS)

    Grishin, D. F.; Grishin, I. D.

    2015-07-01

    Data on the controlled synthesis of polyacrylonitrile and acrylonitrile copolymers with other (meth)acrylic and vinyl monomers upon radical initiation and metal complex catalysis are analyzed. Primary attention is given to the use of metal complexes for the synthesis of acrylonitrile-based (co)polymers with defined molecular weight and polydispersity in living mode by atom transfer radical polymerization. The prospects for using known methods of controlled synthesis of macromolecules for the preparation of acrylonitrile homo- and copolymers as carbon fibre precursors are estimated. The major array of published data analyzed in the review refers to the last decade. The bibliography includes 175 references.

  14. Application of control technology developed in the polyvinyl chloride industry to polymerization processes using acrylonitrile.

    PubMed

    Schoultz, K S; Gideon, J A; Bochinski, J H

    1979-02-01

    Polymerization processes for PVC are sufficiently similar to acrylonitrile polymerization processes to allow a significant transfer of control technology. This transfer should be of value to manufacturers of polyacrylonitrile, ABS/SAN resins, nitrile elastomer and latex who will need to install extensive additional controls to comply with the new permanent standard for acrylonitrile scheduled to be issued by OSHA in late 1978. Control strategies and individual controls developed to limit worker exposure in the PVC industry are described and evaluated relative to applicability to acrylonitrile polymerization processes. PMID:495444

  15. New family of tungstate-responsive transcriptional regulators in sulfate-reducing bacteria.

    PubMed

    Kazakov, Alexey E; Rajeev, Lara; Luning, Eric G; Zane, Grant M; Siddartha, Kavya; Rodionov, Dmitry A; Dubchak, Inna; Arkin, Adam P; Wall, Judy D; Mukhopadhyay, Aindrila; Novichkov, Pavel S

    2013-10-01

    The trace elements molybdenum and tungsten are essential components of cofactors of many metalloenzymes. However, in sulfate-reducing bacteria, high concentrations of molybdate and tungstate oxyanions inhibit growth, thus requiring the tight regulation of their homeostasis. By a combination of bioinformatic and experimental techniques, we identified a novel regulator family, tungstate-responsive regulator (TunR), controlling the homeostasis of tungstate and molybdate in sulfate-reducing deltaproteobacteria. The effector-sensing domains of these regulators are similar to those of the known molybdate-responsive regulator ModE, while their DNA-binding domains are homologous to XerC/XerD site-specific recombinases. Using a comparative genomics approach, we identified DNA motifs and reconstructed regulons for 40 TunR family members. Positional analysis of TunR sites and putative promoters allowed us to classify most TunR proteins into two groups: (i) activators of modABC genes encoding a high-affinity molybdenum and tungsten transporting system and (ii) repressors of genes for toluene sulfonate uptake (TSUP) family transporters. The activation of modA and modBC genes by TunR in Desulfovibrio vulgaris Hildenborough was confirmed in vivo, and we discovered that the activation was diminished in the presence of tungstate. A predicted 30-bp TunR-binding motif was confirmed by in vitro binding assays. A novel TunR family of bacterial transcriptional factors controls tungstate and molybdate homeostasis in sulfate-reducing deltaproteobacteria. We proposed that TunR proteins participate in protection of the cells from the inhibition by these oxyanions. To our knowledge, this is a unique case of a family of bacterial transcriptional factors evolved from site-specific recombinases.

  16. Photolysis of astrophysically relevant acrylonitrile: a matrix experimental study.

    PubMed

    Toumi, A; Couturier-Tamburelli, I; Chiavassa, T; Piétri, N

    2014-04-01

    This report documents the photochemical study of H2C ═ C(H)CN (acrylonitrile) trapped in low-temperature argon matrices and irradiated with a microwave-discharge hydrogen-flow lamp (λ > 120 nm). We succeeded in identifying H2C ═ C(H)NC (isoacrylonitrile) as a photoproduct. HC3N (cyanoacetylene), C2H2:HCN (acetylene:hydrogen cyanide), and C2H2:HNC (acetylene:hydrogen isocyanide) complexes, which are molecules detected in molecular clouds or in the Titan atmosphere, were also identified. No imine product was observed, but other compounds coming from the HC3N photolysis have been found. Fourier transform infrared measurements and (2)H substitution experiments coupled with density functional theory calculations (B3LYP/6-31G**) were performed to confirm the spectral assignments of the photochemical products and intermediate species.

  17. Neurobehavioral alterations in rats exposed to acrylonitrile in drinking water.

    PubMed

    Rongzhu, L; Suhua, W; Guangwei, X; Fangan, H; Ziqiang, C; Fusheng, J; Kacew, S

    2007-03-01

    This study was carried out on rodents, to explore the neurobehavioral effects of acrylonitrile (AN) administered in drinking water. Thirty, male, Sprague-Dawley rats were randomly divided into three groups: two exposure groups (50 and 200 ppm AN), and one control group (tap water without AN). Three tests, including the open field test, rotarod test and spatial water maze, were applied to evaluate locomotor activities, motor co-ordination and learning and memory, respectively, prior to initiation of the treatment, and at Week 4, 8 and 12 postexposure. There were no consistent changes in the open field test, except for locomotion and grooming episodes. In the rotarod test, AN significantly decreased the latencies to fall in a dose and time-dependent manner. In the spatial water maze test, rats exposed to AN for 12 weeks had significantly more training times and longer escape latencies than control animals. These findings indicate that oral exposure to AN induces neurobehavioral alterations in rats.

  18. Hydrolyzed Poly(acrylonitrile) Electrospun Ion-Exchange Fibers

    PubMed Central

    Jassal, Manisha; Bhowmick, Sankha; Sengupta, Sukalyan; Patra, Prabir K.; Walker, Douglas I.

    2014-01-01

    Abstract A potential ion-exchange material was developed from poly(acrylonitrile) fibers that were prepared by electrospinning followed by alkaline hydrolysis (to convert the nitrile group to the carboxylate functional group). Characterization studies performed on this material using X-ray photoelectron spectroscopy, scanning electron microscopy, Fourier-Transform infra-red spectroscopy, and ion chromatography confirmed the presence of ion-exchange functional group (carboxylate). Optimum hydrolysis conditions resulted in an ion-exchange capacity of 2.39 meq/g. Ion-exchange fibers were used in a packed-bed column to selectively remove heavy-metal cation from the background of a benign, competing cation at a much higher concentration. The material can be efficiently regenerated and used for multiple cycles of exhaustion and regeneration. PMID:24963270

  19. Hydration of acrylonitrile to produce acrylamide using biocatalyst in a membrane dispersion microreactor.

    PubMed

    Li, Jiahui; Chen, Jie; Wang, Yujun; Luo, Guangsheng; Yu, Huimin

    2014-10-01

    In this work, a membrane dispersion microreactor was utilized for the hydration of acrylonitrile to produce acrylamide. Through observation using a microscopy, it was found that the acrylonitrile was dispersed into the continuous phase (the aqueous phase contains nitrile hydratase (NHase)) as droplets with a diameter ranged from 25 to 35 μm, hence the mass transfer specific surface area was significantly increased, and the concentration of acrylamide reached 52.5 wt% within 50 min. By contrast, in stirred tanks, the concentration of acrylamide only got 39.5 wt% within 245 min. Moreover, only a few amounts of acrylonitrile were accumulated in this microreactor system. Through optimizing the flow rate, the concentration of acrylamide reached 45.8 wt% within 35 min, the short reaction time greatly weakened the inhibition of acrylonitrile and acrylamide on the enzyme activity, which is suitable for prolonging the life of free cell.

  20. The Rotational Spectrum of Acrylonitrile to 1.67 THz

    NASA Astrophysics Data System (ADS)

    Kisiel, Zbigniew; Pszczółkowski, Lech; Drouin, Brian J.; Brauer, Carolyn S.; Yu, Shanshan; Pearson, John C.

    2009-06-01

    Acrylonitrile (vinyl cyanide) is an astrophysical molecule of sufficient abundance for detection of its ^{13}C isotopologues. In fact this molecule has been identified as one of the 'weed' species, that will contribute a plethora of lines in broadband submillimetre spectra from the new tools of radioastronomy, such as the Herschel Space Observatory or ALMA. We presently report the first stage in extending the knowledge of the rotational spectrum of acrylonitrile well into the THz region. The spectrum was recorded with the jpl cascaded harmonic multiplication instrument in the form of several broadband segments covering 390-540, 818-930, 967-1160, and 1576-1669 GHz. The analysis of the ground state spectrum has been extended up to J=128, K_a=29, and a combined data set of over 3000 fitted lines. It is found that transitions in all measurable vibrational states, inclusive of the ground state, show evidence of perturbations with other states. Several different perturbations between the ground state and v_{11}=1 at 228 cm^{-1} were identified and have been successfully fitted, resulting in E_{11}=228.29994(3) cm^{-1}, to compare with a direct far-infrared value of 228.83(18) cm^{-1}. H.S.P.Müller et al., J. Mol. Spectrosc., 251, 319-325 (2008). B.J.Drouin, F.W.Maiwald, J.C.Pearson, Rev. Sci. Instrum., 76, 093113-1-10 (2005). A.R.H.Cole, A.A.Green, J. Mol. Spectrosc., 48, 246-253 (1973).

  1. Time- and energy-efficient solution combustion synthesis of binary metal tungstate nanoparticles with enhanced photocatalytic activity.

    PubMed

    Thomas, Abegayl; Janáky, Csaba; Samu, Gergely F; Huda, Muhammad N; Sarker, Pranab; Liu, J Ping; van Nguyen, Vuong; Wang, Evelyn H; Schug, Kevin A; Rajeshwar, Krishnan

    2015-05-22

    In the search for stable and efficient photocatalysts beyond TiO2 , the tungsten-based oxide semiconductors silver tungstate (Ag2 WO4 ), copper tungstate (CuWO4 ), and zinc tungstate (ZnWO4 ) were prepared using solution combustion synthesis (SCS). The tungsten precursor's influence on the product was of particular relevance to this study, and the most significant effects are highlighted. Each sample's photocatalytic activity towards methyl orange degradation was studied and benchmarked against their respective commercial oxide sample obtained by solid-state ceramic synthesis. Based on the results herein, we conclude that SCS is a time- and energy-efficient method to synthesize crystalline binary tungstate nanomaterials even without additional excessive heat treatment. As many of these photocatalysts possess excellent photocatalytic activity, the discussed synthetic strategy may open sustainable materials chemistry avenues to solar energy conversion and environmental remediation.

  2. Oral tungstate (Na2WO4) exposure reduces adaptive immune responses in mice after challenge.

    PubMed

    Osterburg, Andrew R; Robinson, Chad T; Mokashi, Vishwesh; Stockelman, Michael; Schwemberger, Sandy J; Chapman, Gail; Babcock, George F

    2014-01-01

    Tungstate (WO²⁻₄) has been identified as a ground water contaminant at military firing ranges and can be absorbed by ingestion. In this study, C57BL6 mice were exposed to sodium tungstate (Na2WO4·2H2O) (0, 2, 62.5, 125, and 200 mg/kg/day) in their drinking water for an initial 28-day screen and in a one-generation (one-gen) model. Twenty-four hours prior to euthanasia, mice were intraperitoneally injected with Staphylococcal enterotoxin B (SEB) (20 μg/mouse) or saline as controls. After euthanasia, splenocytes and blood were collected and stained with lymphocyte and/or myeloid immunophenotyping panels and analyzed by flow cytometry. In the 28-day and one-gen exposure, statistically significant reductions were observed in the quantities of activated cytotoxic T-cells (TCTL; CD3(+)CD8(+)CD71(+)) and helper T-cells (TH; CD3(+)CD4(+)CD71(+)) from spleens of SEB-treated mice. In the 28-day exposures, CD71(+) TCTL cells were 12.87 ± 2.05% (SE) in the 0 tungstate (control) group compared to 4.44 ± 1.42% in the 200 mg/kg/day (p < 0.001) group. TH cells were 4.85 ± 1.23% in controls and 2.76 ± 0.51% in the 200 mg/kg/day (p < 0.003) group. In the one-gen exposures, TCTL cells were 7.98 ± 0.49% and 6.33 ± 0.49% for P and F1 mice after 0 mg/kg/day tungstate vs 1.58 ± 0.23% and 2.52 ± 0.25% after 200 mg/kg/day of tungstate (p < 0.001). Similarly, TH cells were reduced to 6.21 ± 0.39% and 7.20 ± 0.76%, respectively, for the 0 mg/kg/day P and F1 mice, and 2.28 ± 0.41% and 2.85 ± 0.53%, respectively, for the 200 mg/kg/day tungstate P and F1 groups (p < 0.001). In delayed-type hypersensitivity Type IV experiments, tungstate exposure prior to primary and secondary antigen challenge significantly reduced footpad swelling at 20 and 200 mg/kg/day. These data indicate that exposure to tungstate can result in immune suppression that may, in turn, reduce host defense against

  3. MOF-Derived Tungstated Zirconia as Strong Solid Acids toward High Catalytic Performance for Acetalization.

    PubMed

    Wang, Peng; Feng, Jian; Zhao, Yupei; Wang, Shaobin; Liu, Jian

    2016-09-14

    A strong solid acid, tungstated zirconia (WZ), has been prepared first using tungstate immobilized UiO-66 as precursors through a "double-solvent" impregnation method under mild calcination temperature. With moderate W contents, the as-synthesized WZ catalysts possess a high density of acid sites, and the proper heat treatment also has facilely led to a bunch of oligomeric tungsten clusters on stabilized tetragonal ZrO2. The resultant solid acids show an improved catalytic performance toward the benzaldehyde's acetalization in comparison with traditional zirconium hydroxide-prepared WZ. Notably, due to large surface area and additionally introduced strong acid sites, the MOF-derived WZ catalysts afforded conversion up to 86.0%. The facile method endows the WZ catalysts with superior catalytic activities and excellent recyclability, thus opening a new avenue for preparation of metal oxide-based solid superacids and superbases. PMID:27557351

  4. One-step synthesis and luminescence properties of tetragonal double tungstates nanocrystals.

    PubMed

    Wang, Z J; Zhang, Y L; Zhong, J P; Yao, H H; Wang, J; Wu, M M; Meijerink, A

    2016-08-25

    A versatile one-step thermolysis protocol is demonstrated to produce a uniform dispersion of tetragonal double tungstates NaRE(WO4)2 (RE = rare earth) nanocrystals (NCs). Oriented attachment in the [001] direction occurred. Doping with luminescent RE(3+) ions resulted in highly luminescent NCs showing characteristic line emission of the dopant as well as a blue emission assigned to surface adsorbed organic species. PMID:27524472

  5. A photon calorimeter using lead tungstate crystals for the CEBAF HAll A Compton polarimeter

    SciTech Connect

    D. Neyret; T. Pussieux; T. Auger; M. Baylac; E. Burtin; C. Cavata; R. Chipaux; S. Escoffier; N. Falletto; J. Jardillier; S. Kerhoas; D. Lhuillier; F. Marie; C. Veyssiere; J. Ahrens; R. Beck; M. Lang

    2000-05-01

    A new Compton polarimeter is built on the CEBAF Hall A electron beam line. Performances of 10% resolution and 1% calibration are required for the photon calorimeter of this polarimeter. This calorimeter is built with lead tungstate scintillators coming from the CMS electromagnetic calorimeter R&D. Beam tests of this detector have been made using the tagged photon beam line at MAMI, Mainz, and a resolution of 1.76%+2.75%/v+0.41%/E has been measured.

  6. Recycling of Chrome Tanned Leather Dust in Acrylonitrile Butadiene Rubber

    NASA Astrophysics Data System (ADS)

    El-Sabbagh, Salwa H.; Mohamed, Ola A.

    2010-06-01

    Concerns on environmental waste problem caused by chrome tanned leather wastes in huge amount have caused an increasing interest in developing this wastes in many composite formation. This leather dust was used as filler in acrylonitrile butadiene rubber (NBR) before treatment and after treatment with ammonia solution and sod. formate. Different formulations of NBR/ leather dust (untreated-treated with ammonia solution—treated with sod. formate) composites are prepared. The formed composite exhibit a considerable improvement in some of their properties such as rheometric characteristics especially with composites loaded with treated leather dust. Tensile strength, modulus at 100% elongation, hardness and youngs modulus were improved then by further loading start to be steady or decrease. Cross linking density in toluene were increased by incorporation of leather dust treated or untreated resulting in decreases in equilibrium swelling. Distinct increase in the ageing coefficient of both treated and untreated leather with drop in NBR vulcanizates without leather dust. Addition of leather dust treated or untreated exhibit better thermal stability.

  7. Coagulation pretreatment of highly concentrated acrylonitrile wastewater from petrochemical plants.

    PubMed

    Zheng, Dongju; Qin, Lin; Wang, Tao; Ren, Xiaojing; Zhang, Zhongguo; Li, Jiding

    2014-01-01

    Acrylonitrile (AN) wastewater is a heavily polluted and a likely hazardous liquid that is generated during the production of AN. Several chemical methods for the pretreatment of AN wastewater are available in laboratory scale. However, the harsh reaction conditions and high operational cost make these methods undesirable. Until now, four-effect evaporation is the only pretreatment method used for AN wastewater in industry despite its huge energy consumption and high cost. It is difficult to find an energy-saving pretreatment technique from the perspective of industrial application. In this study, a safe and low-cost coagulation technique was developed for the pretreatment of AN wastewater. Three types of inorganic coagulant and three types of polymer coagulant were investigated for the coagulation treatment of highly concentrated AN wastewater from petrochemical plants. The effects of coagulant type, dosage, and coagulation conditions on the pretreatment efficiency of AN wastewater were investigated. The results show that a combination of inorganic and polymer coagulants is effective for the pretreatment of AN wastewater.

  8. Lactoperoxidase catalyzes in vitro activation of acrylonitrile to cyanide.

    PubMed

    Nasralla, Sherry N; Ghoneim, Asser I; Khalifa, Amani E; Gad, Mohamed Z; Abdel-Naim, Ashraf B

    2009-12-15

    Acrylonitrile (ACN) is a widely used industrial chemical. Although it is a well reported animal carcinogen, its current designation to humans is "possibly carcinogenic". The present study aimed at investigating the ability of LPO enzyme system to oxidize ACN to cyanide (CN(-)) in vitro. Detection of CN(-) served as a marker for the possible generation of free radical intermediates implicated in ACN induced toxicity in the activation process. Optimum conditions for the oxidation of ACN to CN(-) were characterized with respect to pH, temperature and time of incubation as well as ACN, LPO and H(2)O(2) concentrations in incubation mixtures. Maximum reaction velocity (V(max)) and Michaelis-Menten constant (K(m)) were assessed. Addition of nitrite (NO(2)(-)) salts to the reaction mixtures significantly enhanced the rate of the reaction. Free radical scavengers (quercetin and trolox C), LPO enzyme inhibitor (resorcinol) and competitors for LPO binding (sodium azide and indomethacin) were found to reduce the rate of CN(-) production. Inclusion of the sulfhydryl compounds glutathione (GSH), NAC (N-acetylcysteine), D-penicillamine or L-cysteine enhanced the rate of ACN oxidation. The present results demonstrate the ability of LPO enzyme system to oxidize ACN to CN(-) and provide insight for the elucidation of ACN chronic toxicity.

  9. Acrylonitrile is a multisite carcinogen in male and female B6C3F1 mice.

    PubMed

    Ghanayem, Burhan I; Nyska, Abraham; Haseman, Joseph K; Bucher, John R

    2002-07-01

    Acrylonitrile is a heavily produced unsaturated nitrile, which is used in the production of synthetic fibers, plastics, resins, and rubber. Acrylonitrile is a multisite carcinogen in rats after exposure via gavage, drinking water, or inhalation. No carcinogenicity studies of acrylonitrile in a second animal species were available. The current studies were designed to assess the carcinogenicity of acrylonitrile in B6C3F1 mice of both sexes. Acrylonitrile was administered by gavage at 0, 2.5, 10, or 20 mg/kg/day, 5 days per week, for 2 years. Urinary thiocyanate and N-acetyl-S-(2-cyanoethyl)-L-cysteine were measured as markers of exposure to acrylonitrile. In general, there were dose-related increases in urinary thiocyanate and N-acetyl-S-(2-cyanoethyl)-L-cysteine concentrations in all dosed groups of mice and at all time points. Survival was significantly (p < 0.001) reduced in the top dose (20 mg/kg) group of male and female mice relative to controls. The incidence of forestomach papillomas and carcinomas was increased in mice of both sexes in association with an increase in forestomach epithelial hyperplasia. The incidence of Harderian gland adenomas and carcinomas was also markedly increased in the acrylonitrile-dosed groups. In female mice, the incidence of benign or malignant granulosa cell tumors (combined) in the ovary in the 10 mg/kg dose group was greater than that in the vehicle control group, but because of a lack of dose response, this was considered an equivocal finding. In addition, the incidences of atrophy and cysts in the ovary of the 10 and 20 mg/kg dose groups were significantly increased. The incidences of alveolar/bronchiolar adenoma or carcinoma (combined) were significantly increased in female mice treated with acrylonitrile at 10 mg/kg/day for 2 years. This was also considered an equivocal result. In conclusion, these studies demonstrated that acrylonitrile causes multiple carcinogenic effects after gavage administration to male and female B6

  10. An experimental Raman and theoretical DFT study on the self-association of acrylonitrile.

    PubMed

    Alía, Jose M; Edwards, Howell G M; Fawcett, W Ronald; Smagala, Thomas G

    2007-02-01

    The liquid structure of acrylonitrile (propenenitrile) has been investigated using Raman spectroscopy and density functional theory (DFT) ab initio calculations with the 6-311++G** basis set. Two different and complementary experimental approaches were undertaken: FT-Raman spectra of 13 acrylonitrile solutions in carbon tetrachloride (concentration range=0.25-12.0 mol.L-1) were studied in detail including principal component analysis (PCA) of the CN stretching band. Furthermore, dispersive Raman spectra of neat acrylonitrile were obtained at eight different temperatures from 238 up to 343 K. The complex and asymmetric acrylonitrile Raman CN stretching band can be decomposed into two components attributed to monomeric and self-associated forms. Ab initio results fully support this assignment and suggest that the self-associated complex is a nonplanar trimer held together by dipole-dipole interactions. At ambient temperature, the composition of acrylonitrile can be expressed as a mixture of 25% monomers and 75% trimers. Close to the boiling point, trimers still represent 65% of the liquid composition. The corresponding enthalpy of association was estimated to be -22+/-2 kJ.mol-1.

  11. CNS tumors and exposure to acrylonitrile: inconsistency between experimental and epidemiology studies.

    PubMed Central

    Collins, J. J.; Strother, D. E.

    1999-01-01

    Acrylonitrile is a potent CNS tumorigen in rats leading to concern that it may be a tumorigen in humans. There have been 12 epidemiology studies of 37,352 workers exposed to acrylonitrile which evaluate CNS cancers. We summarize and evaluate these epidemiology studies for CNS cancers using the methods of meta-analysis. Our analyses indicate that workers with acrylonitrile exposure have null findings for CNS cancer (relative risk = 1.1, 95% confidence interval 0.8-1.5), which are in stark contrast to the projected risk to humans using the rat findings (relative risk = 3.5, 95% confidence interval 3.0-4.0). We discuss several explanations for the inconsistency between animal and human findings, including the possibility that the acrylonitrile-induced rat CNS tumors may not be relevant to humans. Given the rarity of CNS tumors in humans and a lack of understanding of the causal mechanisms of these tumors in rats, however, a more definitive conclusion will have to await additional experimental and observational data. Nevertheless, the epidemiology evidence indicates that acrylonitrile is not a potent CNS tumorigen. PMID:11550315

  12. Tungstate-induced color-pattern modifications of butterfly wings are independent of stress response and ecdysteroid effect.

    PubMed

    Otaki, Joji M; Ogasawara, Tsuyoshi; Yamamoto, Haruhiko

    2005-06-01

    Systemic injections of sodium tungstate, a protein-tyrosine phosphatase (PTPase) inhibitor, to pupae immediately after pupation have been shown to efficiently produce characteristic color-pattern modifications on the wings of many species of butterflies. Here we demonstrated that the tungstate-induced modification pattern was entirely different from other chemically-induced ones in a species of nymphalid butterfly Junonia (Precis) orithya. In this species, the systemic injections of tungstate produced characteristic expansion of black area and shrinkage of white area together with the move of parafocal elements toward the wing base. Overall, pattern boundaries became obscure. In contrast, an entirely different modification pattern, overall darkening of wings, was observed by the injections of stress-inducing chemicals, thapsigargin, ionomycin, or geldanamycin, to pupae under the rearing conditions for the adult summer form. On the ventral wings, this darkening was due to an increase of the proportion of peppered dark scales, which was reminiscent of the natural fall form of this species. Under the same rearing conditions, the injections of ecdysteroid, which is a well-known hormone being responsible for the seasonal polyphenism of nymphalid butterflies, yielded overall expansion of orange area especially around eyespots. Taken together, we conclude that the tungstate-induced modifications are clearly distinguishable from those of stress response and ecdysteroid effect. This conclusion then suggests that the putative PTPase signaling pathway that is sensitive to tungstate uniquely contributes to the wing-wide color-pattern development in butterflies. PMID:15988157

  13. Tungstate-induced color-pattern modifications of butterfly wings are independent of stress response and ecdysteroid effect.

    PubMed

    Otaki, Joji M; Ogasawara, Tsuyoshi; Yamamoto, Haruhiko

    2005-06-01

    Systemic injections of sodium tungstate, a protein-tyrosine phosphatase (PTPase) inhibitor, to pupae immediately after pupation have been shown to efficiently produce characteristic color-pattern modifications on the wings of many species of butterflies. Here we demonstrated that the tungstate-induced modification pattern was entirely different from other chemically-induced ones in a species of nymphalid butterfly Junonia (Precis) orithya. In this species, the systemic injections of tungstate produced characteristic expansion of black area and shrinkage of white area together with the move of parafocal elements toward the wing base. Overall, pattern boundaries became obscure. In contrast, an entirely different modification pattern, overall darkening of wings, was observed by the injections of stress-inducing chemicals, thapsigargin, ionomycin, or geldanamycin, to pupae under the rearing conditions for the adult summer form. On the ventral wings, this darkening was due to an increase of the proportion of peppered dark scales, which was reminiscent of the natural fall form of this species. Under the same rearing conditions, the injections of ecdysteroid, which is a well-known hormone being responsible for the seasonal polyphenism of nymphalid butterflies, yielded overall expansion of orange area especially around eyespots. Taken together, we conclude that the tungstate-induced modifications are clearly distinguishable from those of stress response and ecdysteroid effect. This conclusion then suggests that the putative PTPase signaling pathway that is sensitive to tungstate uniquely contributes to the wing-wide color-pattern development in butterflies.

  14. Analytical method for the determination of acrylonitrile in rat plasma at the nanograms per milliliter level.

    PubMed

    Freshour, N L; Melcher, R G

    1983-01-01

    A method is described for the determination of acrylonitrile (propenenitrile, vinyl cyanide, AN) in rat plasma at the ng/mL level by gas chromatography (GC) utilizing a modified delayed injection technique (DIT) and a nitrogen-phosphorus detector. The method was developed to determine the acrylonitrile plasma profile following administration of various dose levels of AN via different routes. A remote injection apparatus was placed in-line with the purge gas to the precolumn of the DIT. Using this arrangement, matrix interferences in rat plasma samples normally incurred during GC analysis were overcome, while a high sensitivity for acrylonitrile was maintained. The ability to analyze 20-microL samples made serial kills unnecessary and duplicate injections possible with an analysis time of approximately 10 min/sample. The average detection limit for the entire study (3 x background) was 2.0 ng/mL.

  15. Atmospheric chemistry of toxic contaminants. 3. Unsaturated aliphatics: Acrolein, acrylonitrile, maleic anhydride

    SciTech Connect

    Grosjean, D. )

    1990-12-01

    Detailed mechanisms are outlined for the chemical reactions that contribute to in-situ formation and atmospheric removal of the unsaturated aliphatic contaminants acrolein, acrylonitrile, and maleic anhydride. In-situ formation of small amounts of acrolein and maleic anhydride may involve the reaction of OH (and O{sub 3}) with 1,3-dienes and the reaction of OH with aromatic hydrocarbons, respectively. There is no known pathway for in-situ formation of acrylonitrile. Rapid removal of acrolein (half-life = less than one day) and of maleic anhydride (half-life = several hours) is expected from their rapid reactions with OH (major), O{sub 3}, and NO{sub 3}. These reactions lead to formaldehyde and glyoxal from acrolein and to dicarbonyls from maleic anhydride. Acrylonitrile is removed at a slower rate (half-life = 2-7 days) by reaction with OH, leading to formaldehyde and formyl cyanide.

  16. Reaction between CH2 and HCCN: a theoretical approach to acrylonitrile formation in the interstellar medium.

    PubMed

    Shivani; Misra, Alka; Tandon, Poonam

    2014-04-01

    Acrylonitrile (CH2CHCN) was first detected in dense molecular cloud SgrB2. The synthesis of this interstellar molecule is reported to be quite difficult. Therefore, in the present work an attempt has been made to explore the possibility of formation of acrylonitrile from some simple molecules and radicals detected in interstellar space by radical-radical interaction scheme, both in the gas phase and in the icy grains. All calculations are performed using quantum chemical methods with density functional theory (DFT) at the B3LYP/6-311G (d,p) level and Møller-Plesset perturbation theory at the MP2/6-311G (d,p) level. In the discussed chemical pathway, the reaction is found to be totally exothermic and barrier less giving rise to a high probability of acrylonitrile formation in Interstellar space. PMID:25416678

  17. Precision machining, polishing and measurement of mechanical and toxicological properties of lead tungstate crystals for the CMS electromagnetic calorimeter

    SciTech Connect

    Wuest, C.R.; Fuchs, B.A.; Shi, X.

    1995-08-01

    We have developed new machining and polishing techniques that have previously been applied to large scintillating crystal arrays for high energy physics experiments such as the Barium Fluoride Electromagnetic Calorimeter for the GEM Detector at SSCL, the LCsI Electromagnetic Calorimeter for the BaBar Detector at PEP-II B Factory at SLAC and the 110,000 crystal CMS Lead Tungstate Electromagnetic Calorimeter at LHC at CERN. We discuss earlier results achieved with diamond machining and polishing methods and present new results on diamond machining of lead tungstate crystals. Additionally we present new results on mechanical properties of lead tungstate including toxicological data important for the safe handling and processing of this material.

  18. Effect of thermal annealing on the phase evolution of silver tungstate in Ag/WO₃ films.

    PubMed

    Bose, R Jolly; Sreedharan, R Sreeja; Krishnan, R Resmi; Reddy, V R; Gupta, Mukul; Ganesan, V; Sudheer, S K; Pillai, V P Mahadevan

    2015-06-15

    Silver/tungsten oxide multi-layer films are deposited over quartz substrates by RF magnetron sputtering technique and the films are annealed at temperatures 200, 400 and 600°C. The effect of thermal annealing on the phase evolution of silver tungstate phase in Ag/WO3 films is studied extensively using techniques like X-ray diffraction, micro-Raman analysis, atomic force microscopy and photoluminescence studies. The XRD pattern of the as-deposited film shows only the peaks of cubic phase of silver. The film annealed at 200°C shows the presence of XRD peaks corresponding to orthorhombic phase of Ag2WO4 and peaks corresponding to cubic phase of silver with reduced intensity. It is found that, as annealing temperature increases, the volume fraction of Ag decreases and that of Ag2WO4 phase increases and becomes highest at a temperature of 400°C. When the temperature increases beyond 400°C, the volume fraction of Ag2WO4 decreases, due to its decomposition into silver and oxygen deficient phase Ag2W4O13. The micro-Raman spectra of the annealed films show the characteristic bands of tungstate phase which is in agreement with XRD analysis. The surface morphology of the films studied by atomic force microscopy reveals that the particle size and r.m.s roughness are highest for the sample annealed at 400°C. In the photoluminescence study, the films with silver tungstate phase show an emission peak in blue region centered around the wavelength 441 nm (excitation wavelength 256 nm).

  19. TupA: A Tungstate Binding Protein in the Periplasm of Desulfovibrio alaskensis G20

    PubMed Central

    Otrelo-Cardoso, Ana Rita; Nair, Rashmi R.; Correia, Márcia A. S.; Rivas, Maria G.; Santos-Silva, Teresa

    2014-01-01

    The TupABC system is involved in the cellular uptake of tungsten and belongs to the ABC (ATP binding cassette)-type transporter systems. The TupA component is a periplasmic protein that binds tungstate anions, which are then transported through the membrane by the TupB component using ATP hydrolysis as the energy source (the reaction catalyzed by the ModC component). We report the heterologous expression, purification, determination of affinity binding constants and crystallization of the Desulfovibrio alaskensis G20 TupA. The tupA gene (locus tag Dde_0234) was cloned in the pET46 Enterokinase/Ligation-Independent Cloning (LIC) expression vector, and the construct was used to transform BL21 (DE3) cells. TupA expression and purification were optimized to a final yield of 10 mg of soluble pure protein per liter of culture medium. Native polyacrylamide gel electrophoresis was carried out showing that TupA binds both tungstate and molybdate ions and has no significant interaction with sulfate, phosphate or perchlorate. Quantitative analysis of metal binding by isothermal titration calorimetry was in agreement with these results, but in addition, shows that TupA has higher affinity to tungstate than molybdate. The protein crystallizes in the presence of 30% (w/v) polyethylene glycol 3350 using the hanging-drop vapor diffusion method. The crystals diffract X-rays beyond 1.4 Å resolution and belong to the P21 space group, with cell parameters a = 52.25 Å, b = 42.50 Å, c = 54.71 Å, β = 95.43°. A molecular replacement solution was found, and the structure is currently under refinement. PMID:24992597

  20. Analysis of solid solutions stability in scheelite-type molybdates and tungstates

    SciTech Connect

    Zhuravlev, V.D.; Reznitskikh, O.G.; Velikodnyi, Yu.A.; Patrusheva, T.A.; Sivtsova, O.V.

    2011-10-15

    Mutual solubility of bivalent metal molybdates and tungstates with scheelite structure was theoretically estimated by calculating formation enthalpies and the maximal decomposition temperatures of solid solutions at different temperatures. The theoretical stability of continuous solid solutions in binary systems of bivalent metal molybdates and tungstates was found to be higher than reported literature data. After cooling down continuous substitution solid solution should remain in following systems: CaMoO{sub 4}-CdMoO{sub 4}, SrMoO{sub 4}-MMoO{sub 4} (M=Ba, Pb), BaMoO{sub 4}-PbMoO{sub 4}, SrWO{sub 4}-MWO{sub 4} (M=Ca, Pb), and BaWO{sub 4}-PbWO{sub 4}. There is a probability that at room temperature in systems CaMoO{sub 4}-SrMoO{sub 4,} CaWO{sub 4}-PbWO{sub 4}, and BaWO{sub 4}-SrWO{sub 4} the single homogeneity region may decompose to limited solid solutions. It was shown experimentally that a continuous series of scheelite-structure solid solutions M{sub 1-x}M{sup I}{sub x}TO{sub 4} can be formed via citrate synthesis at temperatures below 500 deg. S. - Graphical abstract: Calculated boundaries of solid solutions in BaWO{sub 4}-CaWO{sub 4} (1) and PbMoO{sub 4}-CaMoO{sub 4} (2) systems. Highlights: > Stability of solid solutions molybdates and tungstates has been investigated. > The ionic model for isovalent substitutions was used. > In 'polyhedral substitution model' enthalphies of mixing were calculated. > Most of the examined series of solid solutions is stable at room temperatures. > Solid solutions M{sub 1-x}M{sup I}{sub x}Mo(W)O{sub 4} (x=0-1) were formed via citrate synthesis below 500 S.

  1. Thulium channel waveguide laser in a monoclinic double tungstate with 70% slope efficiency.

    PubMed

    van Dalfsen, K; Aravazhi, S; Grivas, C; García-Blanco, S M; Pollnau, M

    2012-03-01

    Laser experiments were performed on buried, ridge-type channel waveguides in an 8 at. % thulium-doped, yttrium-gadolinium-lutetium codoped monoclinic double tungstate. A maximum slope efficiency of 70% and output powers up to 300 mW about 2.0 μm were obtained in a mirrorless laser resonator, by pumping with a Ti:sapphire laser near 800 nm. To the best of our knowledge, this result represents the most efficient 2 μm channel waveguide laser to date. Lasing is obtained at various wavelengths between 1810 nm and 2037 nm.

  2. Comparison of radiation damage in lead tungstate crystals under pion and gamma irradiation

    SciTech Connect

    Batarin, V.A.; Butler, J.; Davidenko, A.M.; Derevschikov, A.A.; Goncharenko, Y.M.; Grishin, V.N.; Kachanov, V.A.; Khodyrev, V.Y.; Konstantinov, A.S.; Kravtsov, V.I.; Kubota, Y.; Lukanin, V.S.; Matulenko, Y.A.; Melnick, Y.M.; Meschanin, A.P.; Mikhalin, N.E.; Minaev, N.G.; Mochalov, V.V.; Morozov, D.A.; Nogach, L.V.; Ryazantsev, A.V.; /Serpukhov, IHEP /Fermilab /Minnesota U. /Syracuse U. /Nanjing U.

    2003-12-01

    Studies of the radiation hardness of lead tungstate crystals produced by the Bogoroditsk Techno-Chemical Plant in Russia and the Shanghai Institute of Ceramics in China have been carried out at IHEP, Protvino. The crystals were irradiated by a 40 GeV pion beam. After full recovery, the same crystals were irradiated using a {sup 137}Cs {gamma}-ray source. The dose rate profiles along the crystal length were observed to be quite similar. We compare the effects of the two types of radiation on the crystals light output.

  3. ABSORPTION OF CO2 AND SUBSEQUENT VISCOSITY REDUCTION OF AN ACRYLONITRILE COPOLYMER. (R829555)

    EPA Science Inventory

    Acrylonitrile (AN) copolymers (AN content greater than about 85 mol%) are traditionally solution processed to avoid a cyclization and crosslinking reaction that takes place at temperatures where melt processing would be feasible. It is well known that carbon dioxide (CO

  4. 21 CFR 177.1040 - Acrylonitrile/styrene copoly-mer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... viscosity, titled: “Determination of Residual Acrylonitrile and Styrene Monomers-Gas Chromatographic... deionized water or reagent grade n-heptane at reflux temperature for 2 h.1 Minimum 10 pct solution viscosity... Copolymers,” and “Analytical Method for 10% Solution Viscosity of Tyril,” which are incorproated by...

  5. A combined theoretical and experimental study of the electrochemically induced chemisorption of acrylonitrile on nickel, copper, and zinc

    NASA Astrophysics Data System (ADS)

    Fredriksson, C.; Lazzaroni, R.; Brédas, J. L.; Mertens, M.; Jérôme, R.

    1996-08-01

    We report a combined theoretical and experimental study of the interaction between a series of transition metals (Ni, Cu, Zn) and acrylonitrile. We demonstrate experimentally that the transition metal has a selective role in the grafting of electropolymerized acrylonitrile. Nickel and copper substrates support the formation of a polyacrylonitrile film, while zinc does not. Quantum chemical calculations indicate that acrylonitrile molecules form π-d bonds with Ni and Cu atoms, but do not react chemically with a Zn atom, in qualitative agreement with the experiment. Computational results also show that the electron affinity is significantly increased upon chemisorption, promoting radical anion species at the metal surface as initiators for polymerization.

  6. Deposition of Highly Luminescent Zinc Tungstate Thin Films on Various Substrates

    NASA Astrophysics Data System (ADS)

    Farrakhan, Rashad

    Zinc tungstate films have promising applications in small form factor backscatter electron detectors. We are developing a multistep technology for synthesis of these films. Zinc and tungsten were co-sputtered onto substrates through the process of magnetron sputtering. The metallic films were oxidized in a vacuum sealed tube furnace in controlled flow of argon and oxygen at 800 °C. The chemical composition of the film was characterized by Energy-Dispersive X-Ray Spectroscopy (EDS). The structure of the film was investigated by Raman Spectroscopy. The photoluminescence quantum efficiency of the films was found to be 60%. Process parameters for obtaining the desired 1-1 ratio of zinc to tungsten in the film is explored through varying factors such as: the composition of the target used in the sputtering, the power and or voltage used in the sputtering process. Our experiments show that zinc tungstate thin films can be deposited on various substrates with good adhesion and mechanical integrity, and still be efficient light emitters.

  7. Adsorptional removal of methylene blue by guar gum-cerium (IV) tungstate hybrid cationic exchanger.

    PubMed

    Gupta, V K; Pathania, Deepak; Singh, Pardeep; Kumar, Amit; Rathore, B S

    2014-01-30

    Guar gum-cerium (IV) tungstate nanocomposite (GG/CTNC) cationic exchanger was synthesized using simple sol gel method. The GG/CTNC was characterized using X-ray diffraction (XRD), Fourier transmission infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive X-ray spectrophotometer (EDX). The XRD studies confirmed amorphous and fibrous in nature of GG/CTNC. The high percentage of oxygen in the nanocomposite material confirmed the functionality tungstate (WO4(-)). The ion exchange capacity of GG/CTNC for Na(+) ion was observed to be 1.30 mequivg(-1). The hybrid exchanger was used as potential adsorbent for the removal of methylene blue (MB) from aqueous system. The correlation coefficients value indicated a good fit of monolayer Langmuir model to the adsorption of methylene blue onto GG/CTNC. The adsorption kinetic study revealed that the adsorption process followed the pseudo second order kinetic. The Gibbs free energy (ΔG) values confirmed the spontaneous nature of adsorption process.

  8. Compton profiles and electronic structure of monoclinic zinc and cadmium tungstates

    NASA Astrophysics Data System (ADS)

    Meena, B. S.; Heda, N. L.; Mund, H. S.; Ahuja, B. L.

    2015-12-01

    We report the first ever Compton scattering study of ZnWO4 and CdWO4 using 20 Ci 137Cs Compton spectrometer at momentum resolution of 0.34 a.u. To compare the experimental Compton profiles, we have also deduced the momentum densities using density functional theory (DFT) within linear combination of atomic orbitals (LCAO) methods. It is seen that the experimental Compton profiles of both the tungstates give a better agreement with LCAO-DFT calculations within generalized gradient approximation (GGA) employing Perdew-Becke-Ernzerhof (PBE) exchange and correlation energies than other approximations included in the present work. Further, energy bands, density of states (DOS) and band gaps have also been calculated using LCAO-DFT-GGA-PBE scheme and full potential linearized augmented plane wave method. Both the computational schemes show a semiconducting nature of both the tungstates, with a direct band gap at Y point of Brillouin zone. Further, a relative nature of bonding on equal-valence-electron-density scale shows more covalent character in ZnWO4 than CdWO4 which reconciles with the conclusions drawn using integrated DOS and Mulliken's population data.

  9. Metal tungstates at the ultimate two-dimensional limit: fabrication of a CuWO₄ nanophase.

    PubMed

    Denk, Martin; Kuhness, David; Wagner, Margareta; Surnev, Svetlozar; Negreiros, Fabio R; Sementa, Luca; Barcaro, Giovanni; Vobornik, Ivana; Fortunelli, Alessandro; Netzer, Falko P

    2014-04-22

    Metal tungstates (with general formula MWO4) are functional materials with a high potential for a diverse set of applications ranging from low-dimensional magnetism to chemical sensing and photoelectrocatalytic water oxidation. For high level applications, nanoscale control of film growth is necessary, as well as a deeper understanding and characterization of materials properties at reduced dimensionality. We succeeded in fabricating and characterizing a two-dimensional (2-D) copper tungstate (CuWO4). For the first time, the atomic structure of an ultrathin ternary oxide is fully unveiled. It corresponds to a CuWO4 monolayer arranged in three sublayers with stacking O-W-O/Cu from the interface. The resulting bidimensional structure forms a robust framework with localized regions of anisotropic flexibility. Electronically it displays a reduced band gap and increased density of states close to the Fermi level with respect to the bulk compound. These unique features open a way for new applications in the field of photo- and electrocatalysis, while the proposed synthesis method represents a radically new and general approach toward the fabrication of 2-D ternary oxides.

  10. Crystal structure and magnetic properties of potassium erbium double tungstate KEr(WO4)2

    NASA Astrophysics Data System (ADS)

    Borowiec, M. T.; Dyakonov, V. P.; Wozniak, K.; Dobrzycki, L.; Berkowski, M.; Zubov, E. E.; Michalski, E.; Szewczyk, A.; Gutowska, M. U.; Zayarnyuk, T.; Szymczak, H.

    2007-02-01

    Results of structural, magnetic and specific heat investigations of the potassium erbium double tungstate, KEr(WO4)2, are presented. Potassium erbium double-tungstate KEr(WO4)2 single crystals have been grown by the top-seeded solution growth method (TSSG) and modified Czochralski techniques. It crystallizes in the monoclinic crystal structure (C 2/c space group). The unit cell contains four formula units and is described by parameters a = 10.615(2) Å, b = 10.316(2) Å, c = 7.534(2) Å, β = 130.73(3)°. From the x-ray diffraction measurements the fractional atomic coordinates, displacement parameters and interatomic distances have been determined. The specific heat C(T) of the KEr(WO4)2 crystal has been measured over a temperature range of 0.6-300 K. The susceptibility has been studied at T = 0.25-4.0 K. The magnetic phase transition was observed at a temperature of 0.48 K. The magnetization has been measured in the temperature region from 4.2 to 60 K and in magnetic field up to 1.6 T. A strong anisotropy of magnetic properties was found. The temperature and field dependences of susceptibility and magnetization data were used for both elucidation of character of the magnetic ordering and calculation of the exchange and dipole-dipole interaction energies as well as for determination of the possible magnetic structure of KEr(WO4)2.

  11. Two-Dimensional Iron Tungstate: A Ternary Oxide Layer With Honeycomb Geometry

    PubMed Central

    2016-01-01

    The exceptional physical properties of graphene have sparked tremendous interests toward two-dimensional (2D) materials with honeycomb structure. We report here the successful fabrication of 2D iron tungstate (FeWOx) layers with honeycomb geometry on a Pt(111) surface, using the solid-state reaction of (WO3)3 clusters with a FeO(111) monolayer on Pt(111). The formation process and the atomic structure of two commensurate FeWOx phases, with (2 × 2) and (6 × 6) periodicities, have been characterized experimentally by combination of scanning tunneling microscopy (STM), low-energy electron diffraction (LEED), X-ray photoelectron spectroscopy (XPS), and temperature-programmed desorption (TPD) and understood theoretically by density functional theory (DFT) modeling. The thermodynamically most stable (2 × 2) phase has a formal FeWO3 stoichiometry and corresponds to a buckled Fe2+/W4+ layer arranged in a honeycomb lattice, terminated by oxygen atoms in Fe–W bridging positions. This 2D FeWO3 layer has a novel structure and stoichiometry and has no analogues to known bulk iron tungstate phases. It is theoretically predicted to exhibit a ferromagnetic electronic ground state with a Curie temperature of 95 K, as opposed to the antiferromagnetic behavior of bulk FeWO4 materials. PMID:27110319

  12. Simultaneous speciation analysis of chromate, molybdate, tungstate and vanadate in welding fume alkaline extracts by HPLC-ICP-MS.

    PubMed

    Ščančar, Janez; Berlinger, Balázs; Thomassen, Yngvar; Milačič, Radmila

    2015-09-01

    A novel analytical procedure was developed for the simultaneous speciation analysis of chromate, molybdate, tungstate and vanadate by anion-exchange high performance liquid chromatography hyphenated to inductively coupled plasma mass spectrometry (HPLC-ICP-MS). Linear gradient elution from 100% water to 100% 0.7 M NaCl was applied for chromatographic separation of metal species. In standard aqueous solution at neutral pH molybdate, tungstate and vanadate exist in several aqueous species, while chromate is present as a single CrO4(2-) species. Consequently, only chromate can be separated from this solution in a sharp chromatographic peak. For obtaining sharp chromatographic peaks for molybdate, tungstate and vanadate, the pH of aqueous standard solutions was raised to 12. At highly alkaline conditions single CrO4(2-), MoO4(2-) and WO4(2-) are present and were eluted in sharp chromatographic peaks, while VO4(3-) species, which predominates at pH 12 was eluted in slightly broaden peak. In a mixture of aqueous standard solutions (pH 12) chromate, molybdate, tungstate and vanadate were eluted at retention times from 380 to 420 s, 320 to 370 s, 300 to 350 s and 240 to 360 s, respectively. Eluted species were simultaneously detected on-line by ICP-MS recording m/z 52, 95, 182 and 51. The developed procedure was successfully applied to the analysis of leachable concentrations of chromate, molybdate, tungstate and vanadate in alkaline extracts (2% NaOH+3% Na2CO3) of manual metal arc (MMA) welding fumes loaded on filters. Good repeatability and reproducibility of measurement (RSD±3.0%) for the investigated species were obtained in both aqueous standard solutions (pH 12) and in alkaline extracts of welding fumes. Low limits of detection (LODs) were found for chromate (0.02 ng Cr mL(-1)), molybdate (0.1 ng Mo mL(-1)), tungstate (0.1 ng W mL(-1)) and vanadate (0.2 ng V mL(-1)). The accuracy of analytical procedure for the determination of chromate was checked by analysis of

  13. Simultaneous speciation analysis of chromate, molybdate, tungstate and vanadate in welding fume alkaline extracts by HPLC-ICP-MS.

    PubMed

    Ščančar, Janez; Berlinger, Balázs; Thomassen, Yngvar; Milačič, Radmila

    2015-09-01

    A novel analytical procedure was developed for the simultaneous speciation analysis of chromate, molybdate, tungstate and vanadate by anion-exchange high performance liquid chromatography hyphenated to inductively coupled plasma mass spectrometry (HPLC-ICP-MS). Linear gradient elution from 100% water to 100% 0.7 M NaCl was applied for chromatographic separation of metal species. In standard aqueous solution at neutral pH molybdate, tungstate and vanadate exist in several aqueous species, while chromate is present as a single CrO4(2-) species. Consequently, only chromate can be separated from this solution in a sharp chromatographic peak. For obtaining sharp chromatographic peaks for molybdate, tungstate and vanadate, the pH of aqueous standard solutions was raised to 12. At highly alkaline conditions single CrO4(2-), MoO4(2-) and WO4(2-) are present and were eluted in sharp chromatographic peaks, while VO4(3-) species, which predominates at pH 12 was eluted in slightly broaden peak. In a mixture of aqueous standard solutions (pH 12) chromate, molybdate, tungstate and vanadate were eluted at retention times from 380 to 420 s, 320 to 370 s, 300 to 350 s and 240 to 360 s, respectively. Eluted species were simultaneously detected on-line by ICP-MS recording m/z 52, 95, 182 and 51. The developed procedure was successfully applied to the analysis of leachable concentrations of chromate, molybdate, tungstate and vanadate in alkaline extracts (2% NaOH+3% Na2CO3) of manual metal arc (MMA) welding fumes loaded on filters. Good repeatability and reproducibility of measurement (RSD±3.0%) for the investigated species were obtained in both aqueous standard solutions (pH 12) and in alkaline extracts of welding fumes. Low limits of detection (LODs) were found for chromate (0.02 ng Cr mL(-1)), molybdate (0.1 ng Mo mL(-1)), tungstate (0.1 ng W mL(-1)) and vanadate (0.2 ng V mL(-1)). The accuracy of analytical procedure for the determination of chromate was checked by analysis of

  14. Fascinating and challenging role of tungstate promoted vanadium phosphate towards solvent free esterification of oleic acid.

    PubMed

    Behera, Gobinda Chandra; Parida, K M

    2012-01-28

    A novel solid acid catalyst has been extensively used for the esterification reaction. Herein, tungstate promoted vanadium phosphate material is fabricated from its precursor, VOHPO(4)·0.5H(2)O and its catalytic activities and structure are investigated in detail. This kind of catalyst is, for the first time, applied for the effective production of biodiesel from fatty acids. Although vanadium phosphate has been extensively used in gas phase oxidation reactions, it has not drawn much attention for its application in liquid phase reactions. Our recent results indicate that vanadium phosphate is an effective, minimally polluting and re-usable catalyst that is highly suited to the production of biodiesel from fatty acids. This work extends the possibility of using VPO in other liquid phase reactions.

  15. Synergistic inhibitive effect of tartarate and tungstate in preventing steel corrosion in aqueous media

    NASA Astrophysics Data System (ADS)

    Jabeera, B.; Shibli, S. M. A.; Anirudhan, T. S.

    2006-03-01

    The inhibitive effect of tartarate was studied as a coinhibitor with tungstate in preventing carbon steel corrosion in aqueous solutions. Open circuit potential measurements, weight-loss measurements and polarization studies were conducted to understand the domains of corrosion and passivation. Tartarate ions, even at low concentration, showed excellent synergistic corrosion inhibition characteristics. A mixture of 500 ppm each of the inhibitors was found to be optimum inhibitor combination. This inhibitor combination showed inhibition efficiency as high as 98%. Tartarate in the synergistic inhibitor combination did not reveal any dominant role in shifting the surface potential, even though it showed substantial passivation effect. The present study explores and evaluates the synergistic combination as a potential inhibitor system in combating corrosion on carbon steel surface.

  16. Scintillation of lead tungstate crystal studied with single-electron beam from KUFEL

    SciTech Connect

    Rizwan, Mohamad Uozumi, Yusuke; Matsuo, Kazuki; Ohgaki, Hideaki; Kii, Toshiteru; Zen, Heishun; Tsamalaidze, Zviadi; Evtoukhovitch, Petr; Valentin, Samoilov

    2015-04-29

    Lead tungstate (PWO) crystal has a very fast response, high atomic density and high radiation hardness. Therefore, they are suitable to be used for high-energy nuclear data measurements under high-background circumstances. Although a good electron-ion separation with a pulse shape analysis technique is essential, scintillation pulse shapes have not been observed with electron beams of a wide energy range. A single-electron beam technique has been developed at Kyoto University Free Electron Laser (KUFEL), and electron beams of 4-38 MeV are available. During the experiments, single electron beams bombarded a PWO crystal. By using oscilloscope we observed scintillation pulses of a PWO crystal coupled with a photomultiplier tube. Measured spectra were compared with the simulation code of EGS5 to analyze scattering effects. As the result, the pulse amplitudes show good linearity and the pulse shapes are almost constant in the observed energy range.

  17. Pathogenesis of neurotoxicity of acrylates acrylonitrile and acrylamide: from cell to organism.

    PubMed

    Tarskikh, M M; Klimatskaya, L G; Kolesnikov, S I

    2013-08-01

    The incubation of 10 mM acrylamide (in vitro) with rat brain homogenate was followed by a decrease in catalase activity by 48% as soon as 5 min after addition of acrylate to the incubation medium. Activity of this enzyme remained low 30 min after the start of the experiment. Acute poisoning with this acrylate was accompanied by LPO activation in rat brain 24 h after injection. Exposure to acrylonitrile during occupational contacts with this monomer was followed by accumulation of adducts of acrylate with erythrocytic hemoglobin in human blood. In accordance with previously observed data, modern scheme of neurotropic effects of acrylonitrile and acrylamide was proposed. This scheme explained specific features of clinical syndromes induced by acute and chronic exposure to these toxic agents. PMID:24143365

  18. Detection of acrolein and acrylonitrile with a pulsed room temperature quantum cascade laser

    NASA Astrophysics Data System (ADS)

    Manne, J.; Jäger, W.; Tulip, J.

    2010-06-01

    We investigated the use of a pulsed, distributed feedback quantum cascade laser centered at 957 cm-1 in combination with an astigmatic Herriot cell with 250 m path length for the detection of acrolein and acrylonitrile. These molecules have been identified as hazardous air-pollutants because of their adverse health effects. The spectrometer utilizes the intra-pulse method, where a linear frequency down-chirp, that is induced when a top-hat current pulse is applied to the laser, is used for sweeping across the absorption line. Up to 450 ns long pulses were used for these measurements which resulted in a spectral window of ~2.2 cm-1. A room temperature mercury-cadmium-telluride detector was used, resulting in a completely cryogen free spectrometer. We demonstrated detection limits of ~3 ppb for acrylonitrile and ~6 ppb for acrolein with ~10 s averaging time. Laser characterization and optimization of the operational parameters for sensitivity improvement are discussed.

  19. Preparation and characterization of zinc sulphide nanocomposites based on acrylonitrile butadiene rubber

    NASA Astrophysics Data System (ADS)

    Ramesan, M. T.; Nihmath, A.; Francis, Joseph

    2013-06-01

    Rubber composite based on acrylonitrile butadiene rubber (NBR) reinforced with nano zinc sulphide (ZnS) have been prepared via vulcanization process and characterized by several techniques. Processing characteristics such as scorch time, optimum cure time decreases with increase in concentration of nano filler in acrylonitrile butadiene rubber. Mechanical properties such as tensile and tear strength increases with increase in concentration of nano filler up to 7 phr of loading thereafter the value decreases, whereas hardness, and flame resistance increases with the dosage of fillers. These enhanced properties are due to the homogenous dispersion of nano fillers in NBR matrix, which is evidenced from the structure that evaluated using X-ray diffraction (XRD) and scanning electron microscopy (SEM).

  20. BK channel activation by tungstate requires the β1 subunit extracellular loop residues essential to modulate voltage sensor function and channel gating.

    PubMed

    Fernández-Mariño, Ana I; Valverde, Miguel A; Fernández-Fernández, José M

    2014-07-01

    Tungstate, a compound with antidiabetic, antiobesity, and antihypertensive properties, activates the large-conductance voltage- and Ca(2+)-dependent K(+) (BK) channel containing either β1 or β4 subunits. The BK activation by tungstate is Mg(2+)-dependent and promotes arterial vasodilation, but only in precontracted mouse arteries expressing β1. In this study, we further explored how the β1 subunit participates in tungstate activation of BK channels. Activation of heterologously expressed human BKαβ1 channels in inside-out patches is fully dependent on the Mg(2+) sensitivity of the BK α channel subunit even at high (10 μM) cytosolic Ca(2+) concentration. Alanine mutagenesis of β1 extracellular residues Y74 or S104, which destabilize the active voltage sensor, greatly decreased the tungstate-induced left-shift of the BKαβ1 G-V curves in either the absence or presence of physiologically relevant cytosolic Ca(2+) levels (10 μM). The weakened tungstate activation of the BKαβ1Y74A and BKαβ1S104A mutant channels was not related to decreased Mg(2+) sensitivity. These results, together with previously published reports, support the idea that the putative binding site for tungstate-mediated BK channel activation is located in the pore-forming α channel subunit, around the Mg(2+) binding site. The role of β1 in tungstate-induced channel activation seems to rely on its interaction with the BK α subunit to modulate channel activity. Loop residues that are essential for the regulation of voltage sensor activation and gating of the BK channel are also relevant for BK activation by tungstate.

  1. Lasing properties of new Nd 3+-doped tungstate, molybdate, and fluoride materials under selective optical pumping

    NASA Astrophysics Data System (ADS)

    Šulc, Jan; Jelínkova, Helena; Basiev, Tolstoban T.; Doroschenko, Maxim E.; Ivleva, Ludmila I.; Osiko, Vyacheslav V.; Zverev, Peter G.

    2006-02-01

    The purpose of this work was to determine the relative efficiencies of new Nd 3+-doped laser active/Raman - tungstate, molybdate, and fluoride - materials (SrWO 4, PbWO 4, BaWO 4, SrMoO 4, PbMoO 4, SrF II, and LaF 3) under selective longitudinal optical pumping by the alexandrite (~750nm), or diode (~800nm) laser. Crystals with various length, orientations and active ions concentrations were tested. To optimize the output of the tested lasers a set of input dichroic and output dielectric mirrors with different reflectivities were used. For realized lasers operating at pulsed free-running regime, threshold energy, slope efficiency, emission wavelength, and radiation polarization were determined. For each crystal, fluorescence lifetime and absorption coefficient under given pumping were established. The slope efficiency in case of Nd 3+:PbMoO 4 laser at wavelength 1054nm was measured to be 54.3% with total efficiency of 46% which is the best result obtained for all new tested crystals. For Nd 3+ doped SrWO 4, PbWO 4, and BaWO 4 crystals simultaneous laser and self-Raman emission were demonstrated in Q-switched regime. Thus newly proposed laser Raman crystals demonstrate high efficiency for Nd 3+ laser oscillations comparable with well known and widely used Nd:KGW crystal. Further improvement in the quality of tungstate and molybdate type crystals should result in further increase in lasing efficiency at 1.06μm wavelength. Self Raman frequency conversion of Nd 3+-laser oscillations in these crystals should result in high efficient pulse shortening, high peak power and new wavelengths in 1.2-1.5μm wavelength region.

  2. Biomonitoring following a chemical incident with acrylonitrile and ethylene in 2008.

    PubMed

    Leng, Gabriele; Gries, Wolfgang

    2014-12-15

    The analytical determination of hemoglobin adducts was used as an effective biomonitoring tool after a fire outbrake at a chemical plant close to Cologne/Germany in 2008. More than 1000 people (e.g. fire-men, police officers, and workers) were potentially exposed to acrylonitrile and ethylene. Air monitoring in the surrounding was performed, and acrylonitrile was measured in concentrations up to 20 ppm, the mean value being 7 ppm (time range: 8 h). As many people were concerned about their individual body burden, biomonitoring was recommended for all people involved. 816 persons took advantage of this opportunity and came for blood sampling to the occupational health department of our company. Regarding the lifespan of erythrocytes up to 3 months, it was possible to analyze hemoglobin adducts of acrylonitrile and ethylene during and after the accident. In case of acrylonitrile the hemoglobin adduct N-(2-cyanoethyl) valine and regarding ethylene, N-(2-hydroxyethyl) valine was determined. As a result, the body burden was in nearly all cases within our internal adduct reference values (CyEtVal<15 μg/L blood or <612 pmol/g globin; HyEtVal<15 μg/L blood or 646 pmol/g globin). In about 1% of the cases, the adduct concentrations were slightly above these reference values. This means that the body burden measured by biomonitoring turned out to be far lower than the one expected from the air data. Therefore, following chemical incidents, in case biomonitoring is meaningful, it is highly recommended beside of air monitoring.

  3. Cobalt-mediated radical polymerization of acrylonitrile: kinetics investigations and DFT calculations.

    PubMed

    Debuigne, Antoine; Michaux, Catherine; Jérôme, Christine; Jérôme, Robert; Poli, Rinaldo; Detrembleur, Christophe

    2008-01-01

    The successful controlled homopolymerization of acrylonitrile (AN) by cobalt-mediated radical polymerization (CMRP) is reported for the first time. As a rule, initiation of the polymerization was carried out starting from a conventional azo-initiator (V-70) in the presence of bis(acetylacetonato)cobalt(II) ([Co(acac)(2)]) but also by using organocobalt(III) adducts. Molar concentration ratios of the reactants, the temperature, and the solvent were tuned, and the effect of these parameters on the course of the polymerization is discussed in detail. The best level of control was observed when the AN polymerization was initiated by an organocobalt(III) adduct at 0 degrees C in dimethyl sulfoxide. Under these conditions, poly(acrylonitrile) with a predictable molar mass and molar mass distribution as low as 1.1 was prepared. A combination of kinetic data, X-ray analyses, and DFT calculations were used to rationalize the results and to draw conclusions on the key role played by the solvent molecules in the process. These important mechanistic insights also permit an explanation of the unexpected "solvent effect" that allows the preparation of well-defined poly(vinyl acetate)-b-poly(acrylonitrile) by CMRP.

  4. Alteration of Acrylonitrile-Methylacrylate-Butadiene Terpolymer by Nocardia rhodochrous and Penicillium notatum†

    PubMed Central

    Antoine, A. D.; Dean, A. V.; Gilbert, S. G.

    1980-01-01

    [14C]Barex-210, a terpolymer of acrylonitrile, methylacrylate, and butadiene, was tested for bioconversion. Powdered samples of polymer, each specifically 14C labeled at different carbon atoms of the polymer, were incubated with either Nocardia rhodochrous or Penicillium notatum in an enriched growth medium for various periods of time. After 6 months of incubation, the 14C-labeled polymer was transformed from a high-molecular-weight material completely soluble in dimethyl formamide (DMF) into both a lower-molecular-weight form still soluble in DMF and a second form that was no longer soluble in DMF. The amount of 14C-labeled carbon atoms converted into DMF-insoluble material was 8% of the backbone carbon-carbon atoms and 12% of the side-chain nitrile and acrylate atoms from the acrylonitrile-methylacrylate copolymer and 60% of the elastomer (acrylonitrile-butadiene copolymer) atoms. Metabolism of the polymer was not established from measurements of metabolic 14CO2. Evolution of 14CO2 amounted to only 0.3, 0.6, 1.8, and 3.3% of these four fractions, respectively. Although the transformation of high-molecular-weight polymer into DMF-insoluble material was rapid in the early stages of microbial growth, the accompanying CO2 evolution was much slower. Further evidence of polymer alteration was indicated by the infrared spectrum of the insoluble material, which showed a disappearance of the nitrile and methylacrylate peaks. PMID:16345541

  5. Acrylonitrile polymerization by Cy3PCuMe and (Bipy)2FeEt2.

    PubMed

    Schaper, Frank; Foley, Stephen R; Jordan, Richard F

    2004-02-25

    Cy(3)PCuMe (1) undergoes reversible ligand redistribution at low temperature in solution to form the tight ion pair [Cu(PCy(3))(2)][CuMe(2)] (3). The structure of 3 was assigned on the basis of (i) the stoichiometry of the 1 = 3 equilibrium, (ii) the observation of a triplet for the PCy(3) C1 (13)C NMR resonance due to virtual coupling to two (31)P nuclei, and (iii) reverse synthesis of 1 by combining separately generated Cu(PCy(3))(2)(+) and CuMe(2)(-) ions. Complex 1 and [Cu(PCy(3))(2)][PF(6)] (5) coordinate additional PCy(3) to form (Cy(3)P)(2)CuMe and [Cu(PCy(3))(3)][PF(6)], respectively, while 3 does not. Complex 1, free PCy(3), and (bipy)(2)FeEt(2) (2) each initiate the polymerization of acrylonitrile. In each case, the polyacrylonitrile contains branches that are characteristic of an anionic polymerization mechanism. The major initiator in acrylonitrile polymerization by 1 is PCy(3), which is liberated from 1. A transient iron hydride complex is proposed to initiate acrylonitrile polymerization by 2. PMID:14971946

  6. Toward a mid-infrared femtosecond laser system with suspended-core tungstate-tellurite glass fibers.

    PubMed

    Anashkina, E A; Andrianov, A V; Dorofeev, V V; Kim, A V

    2016-06-10

    A simple design of a fiber laser system for generating high-quality pulses with a duration of order 100 fs with ultrabroad wavelength tunability in the 2-5 μm range is discussed. This design incorporates conventional fs near-IR lasers and specially developed tungstate-tellurite fibers with two zero-dispersion wavelengths (ZDW) and relies on nonlinear wavelength conversion via either soliton self-frequency shift (SSFS) or red-shifted dispersive wave (DW) generation. The fiber parameters needed for such optical conversion have been scanned numerically and showed a possibility of SSFS beyond 4 μm and of DW generation beyond 5 μm. We have also studied and prepared tungstate-tellurite glasses and preforms that are highly stable against crystallization, exhibit extremely low level of hydroxyl groups absorption, and from which the suspended-core two-ZDW fibers can be manufactured. PMID:27409007

  7. On the nature of defect states in tungstate nanoflake arrays as promising photoanodes in solar fuel cells.

    PubMed

    Mohamed, Aya M; Amer, Ahmad W; AlQaradawi, Siham Y; Allam, Nageh K

    2016-08-10

    An electrochemical method is presented to study the nature of the defect states in sub-stoichiometric tungsten oxide nanoflake photoanodes used in water splitting. First, stoichiometric/sub-stoichiometric tungstate nanoflake arrays were deliberately developed via annealing under different atmospheres (air, O2, and H2) in different sequences. UV-Vis diffuse reflectance spectra and Tauc analysis indicated the presence of oxygen vacancies, which was also confirmed via XRD and Raman analysis, with samples annealed in an air/O2 sequence resulting in the most stoichiometric monoclinic structures. A defect sensitivity factor was proposed to explain the nature of defects whether they are deep or shallow. Mott-Schottky analysis was used to confirm the expected defect donor densities, as well as to confirm the nature of the developed oxygen vacancy defect states. The tungstate photoanodes were tested in photoelectrochemical water splitting cells and their photoconversion efficiency was demonstrated and discussed in detail. PMID:27453354

  8. Polyol-mediated low-temperature synthesis of crystalline tungstate nanoparticles MWO4 (M = Mn, Fe, Co, Ni, Cu, Zn)

    NASA Astrophysics Data System (ADS)

    Ungelenk, Jan; Speldrich, Manfred; Dronskowski, Richard; Feldmann, Claus

    2014-05-01

    A polyol-mediated synthesis is presented as a general access to nanoscaled transition-metal tungstates MWO4 (M = Mn, Fe, Co, Ni, Cu, Zn). Using simple inorganic salts as starting materials, uniform and readily crystalline nanoparticles are prepared under mild conditions (T < 220 °C). The nanoparticles are of high quality in terms of small diameter (<20 nm), high surface area (up to 200 m2 g-1), phase purity and yield (>85%). Size, morphology and composition can be adjusted by precise variation of the reaction parameters, including type of starting material, duration and temperature of reaction. The transition-metal tungstate nanoparticles are fully functional, exhibiting typical properties of this class of materials, for instance, superparamagnetism (CoWO4), luminescence (ZnWO4) and photocatalytic activity (CuWO4).

  9. Assessing the performance under ionising radiation of lead tungstate scintillators for EM calorimetry in the CLAS12 Forward Tagger

    NASA Astrophysics Data System (ADS)

    Fegan, S.; Auffray, E.; Battaglieri, M.; Buchanan, E.; Caiffi, B.; Celentano, A.; Colaneri, L.; D`Angelo, A.; De Vita, R.; Dormenev, V.; Fanchini, E.; Lanza, L.; Novotny, R. W.; Parodi, F.; Rizzo, A.; Sokhan, D.; Tarasov, I.; Zonta, I.

    2015-07-01

    The well-established technology of electromagnetic calorimetry using Lead Tungstate crystals has recently seen an upheaval, with the closure of one of the most experienced large-scale suppliers of such crystals, the Bogoroditsk Technical Chemical Plant (BTCP), which was instrumental in the development of mass production procedures for PWO-II, the current benchmark for this scintillator. Obtaining alternative supplies of Lead Tungstate crystals matching the demanding specifications of contemporary calorimeter devices now presents a significant challenge to detector research and development programmes. In this paper we describe a programme of assessment carried out for the selection, based upon the performance under irradiation, of Lead Tungstate crystals for use in the Forward Tagger device, part of the CLAS12 detector in Hall B at Jefferson Lab. The crystals tested were acquired from SICCAS, the Shanghai Institute of Ceramics, Chinese Academy of Sciences. The tests performed are intended to maximise the performance of the detector within the practicalities of the crystal manufacturing process. Results of light transmission, before and after gamma ray irradiation, are presented and used to calculate dk, the induced radiation absorption coefficient, at 420 nm, the peak of the Lead Tungstate emission spectrum. Results for the SICCAS crystals are compared with identical measurements carried out on Bogoroditsk samples, which were acquired for the Forward Tagger development program before the closure of the facility. Also presented are a series of tests performed to determine the feasibility of recovering radiation damage to the crystals using illumination from an LED, with such illumination available in the Forward Tagger from a light monitoring system integral to the detector.

  10. Steady-state Raman gain coefficients of potassium-gadolinium tungstate at the wavelength of 532 nm

    NASA Astrophysics Data System (ADS)

    Chulkov, R.; Markevich, V.; Orlovich, V.; El-Desouki, M.

    2015-12-01

    Stokes generation has been considered under the Fourier-limited nanosecond pulse excitation to find Raman gain coefficients in potassium-gadolinium tungstate. Data of numerical simulation under spontaneous Stokes initiation, light diffraction, and optical feedback have been compared with experimental results to reveal coefficient values of 14 ± 3 and 11 ± 3 cm/GW for the p[mm]p and p[gg]p sample orientations, respectively, at 532 nm wavelength.

  11. Comparative studies on the removal of heavy metals ions onto cross linked chitosan-g-acrylonitrile copolymer.

    PubMed

    Shankar, P; Gomathi, Thandapani; Vijayalakshmi, K; Sudha, P N

    2014-06-01

    The graft copolymerization of acrylonitrile onto cross linked chitosan was carried out using ceric ammonium nitrate as an initiator. The prepared cross linked chitosan-g-acrylonitrile copolymer was characterized using FT-IR and XRD studies. The adsorption behavior of chromium(VI), copper(II) and nickel(II) ions from aqueous solution onto cross linked chitosan graft acrylonitrile copolymer was investigated through batch method. The efficiency of the adsorbent was identified from the varying the contact time, adsorbent dose and pH. The results evident that the adsorption of metal ions increases with the increase of shaking time and metal ion concentration. An optimum pH was found to be 5.0 for both Cr(VI) and Cu(II), whereas the optimum pH is 5.5 for the adsorption of Ni(II) onto cross linked chitosan-g-acrylonitrile copolymer. The Langmuir and Freundlich adsorption models were applied to describe the isotherms and isotherm constants. Adsorption isothermal data could be well interpreted by the Freundlich model. The kinetic experimental data properly correlated with the second-order kinetic model. From the above results it was concluded that the cross linked chitosan graft acrylonitrile copolymer was found to be the efficient adsorbent for removing the heavy metals under optimum conditions.

  12. Characterisation of recycled acrylonitrile-butadiene-styrene and high-impact polystyrene from waste computer equipment in Brazil.

    PubMed

    Hirayama, Denise; Saron, Clodoaldo

    2015-06-01

    Polymeric materials constitute a considerable fraction of waste computer equipment and polymers acrylonitrile-butadiene-styrene and high-impact polystyrene are the main thermoplastic polymeric components found in waste computer equipment. Identification, separation and characterisation of additives present in acrylonitrile-butadiene-styrene and high-impact polystyrene are fundamental procedures to mechanical recycling of these polymers. The aim of this study was to evaluate the methods for identification of acrylonitrile-butadiene-styrene and high-impact polystyrene from waste computer equipment in Brazil, as well as their potential for mechanical recycling. The imprecise utilisation of symbols for identification of the polymers and the presence of additives containing toxic elements in determinate computer devices are some of the difficulties found for recycling of acrylonitrile-butadiene-styrene and high-impact polystyrene from waste computer equipment. However, the considerable performance of mechanical properties of the recycled acrylonitrile-butadiene-styrene and high-impact polystyrene when compared with the virgin materials confirms the potential for mechanical recycling of these polymers.

  13. Decrease of reduced glutathione in isolated rat hepatocytes caused by acrolein, acrylonitrile, and the thermal degradation products of styrene copolymers.

    PubMed

    Zitting, A; Heinonen, T

    1980-01-01

    Decrease of reduced glutathione (GSH) was induced in isolated rat hepatocytes by incubation with acrolein or acrylonitrile for 120 min or exposure to the products of oxidative thermal degradation of acrylonitrile-butadiene-styrene copolymer (ABS), styrene-acrylonitrile copolymer (SAN), and high impact polystyrene (SB). The decrease of GSH by acrolein was rapid but the cells soon recovered at acrolein concentrations of 0.025--0.25 mM. 0.5 mM acrolein depleted the cells of GSH and they were uncapable of further GSH synthesis. At concentrations of 0.25--0.5 mM concomitant lipid peroxidation impaired the integrity of the cell membranes. Also acrylonitrile induced a dose dependent GSH decrease at concentrations of 0.05--1 mM. Neither membrane damage nor lipid peroxidation was detected during 120-min incubations at these acrylonitrile concentrations. The thermal degradation products of ABS, SAN and SB caused a decrease of GSH in hepatocytes. The extent of the decrease depended on the degradation temperature and the type of the plastic. The membrane integrity was impaired in the cases where GSH was depleted almost completely; ABS degraded at 350 degrees C and SB at 250 degrees C. The measurements of lipid peroxidation by the thiobarbituric acid and the diene conjugation methods were impossible because the degradation products contained compounds which interfered with these tests.

  14. Sequential shape-selective adsorption and photocatalytic transformation of acrylonitrile production wastewater.

    PubMed

    Dai, Yunrong; Song, Yonghui; Tu, Xiang; Jiang, Yanpeng; Yuan, Yu

    2015-11-15

    Acrylonitrile production wastewater has been widely recognized as one type of refractory organic wastewater because of its complicated composition and low bioavailability. It usually contains plenty of micromolecular nitrile and pyridine, resulting in high chemical oxygen demand (CODCr), total organic carbon (TOC) and total nitrogen (TN) concentrations. In this study, a novel microporous zeolite, CS-Z1, was developed as an adsorbent for rapidly shape-selective adsorption of the micromolecular pollutants from the acrylonitrile production wastewater, and a visible light-driven Ti-β-Bi2O3 photocatalysis was introduced to sequentially treat the residual macromolecular pollutants for complete purification. The adsorption processes by CS-Z1 were mostly achieved within the first 5 min, and the equilibrium was reached quickly after 30 min, where the CODCr, TOC and TN removal efficiencies of the wastewater were as high as 93.5%, 92.2% and 96.8%, respectively, much higher than those by other adsorbents. Furthermore, the adsorption efficiencies of CS-Z1 were barely affected by the variation of pH value and temperature, which was mainly attributed to the shape-selective adsorption mechanism of the CS-Z1 zeolite. The Ti-β-Bi2O3 photocatalysis could remove more than 95% of the residual macromolecular pollutants in the wastewater, where a synergistic mechanism of reduction-oxidation/polymerization was proposed. In a 108 h of CS-Z1 adsorption and Ti-β-Bi2O3 photocatalysis sequential process, the CODCr, TOC and TN concentrations was reduced to below 20, 7 and 5 mg L(-1), respectively, demonstrating the excellent practical potential of the sequential treatment system for acrylonitrile production wastewater.

  15. Deposition of acrylonitrile cluster ions on solid substrates: thin film formation by intracluster polymerization products.

    PubMed

    Yoshida, Hiroyuki; Sato, Naoki

    2006-03-01

    Cluster anions of acrylonitrile (AN), known to give intracluster anionic polymerization products, were deposited on solid substrates. The obtained films were examined by using infrared absorption spectroscopy, X-ray photoemission spectroscopy, and gel permeation chromatography with the aid of quantum chemical calculations. The acquired spectroscopic data are similar to those of polyacrylonitrile (PAN), while the normal polymerization of AN or reactions related to PAN seemed not to occur noticeably. On the contrary, the product analysis shows that most of the constituent molecules of the films are formed via cyclohexane-1,3,5-tricarbonitrile (CHTCN), a dominant product of the intracluster polymerization of AN, accompanied by fragmentation and dimerization. PMID:16509718

  16. Detection of hydrogen dissolved in acrylonitrile butadiene rubber by 1H nuclear magnetic resonance

    NASA Astrophysics Data System (ADS)

    Nishimura, Shin; Fujiwara, Hirotada

    2012-01-01

    Rubber materials, which are used for hydrogen gas seal, can dissolve hydrogen during exposure in high-pressure hydrogen gas. Dissolved hydrogen molecules were detected by solid state 1H NMR of the unfilled vulcanized acrylonitrile butadiene rubber. Two signals were observed at 4.5 ppm and 4.8 ppm, which were assignable to dissolved hydrogen, in the 1H NMR spectrum of NBR after being exposed 100 MPa hydrogen gas for 24 h at room temperature. These signals were shifted from that of gaseous hydrogen molecules. Assignment of the signals was confirmed by quantitative estimation of dissolved hydrogen and peak area of the signals.

  17. Photocatalytic generation of syngas using combustion-synthesized silver bismuth tungstate.

    PubMed

    de Tacconi, Norma R; Timmaji, Hari Krishna; Chanmanee, Wilaiwan; Huda, Muhammad N; Sarker, Pranab; Janáky, Csaba; Rajeshwar, Krishnan

    2012-08-27

    Silver bismuth tungstate (AgBiW(2)O(8)) nanoparticles were prepared for the first time by solution combustion synthesis by using the corresponding metal nitrates as the precursor and urea as the fuel. These nanoparticles were subsequently modified with Pt catalyst islands using a photocatalytic procedure and used for the photogeneration of syngas (CO+H(2)). Formic acid was used for this purpose for the in situ generation of CO(2) and its subsequent reduction to CO. In the absence of Pt modification, H(2) was not obtained in the gas products evolved. These results were compared with those obtained with acetic acid in place of formic acid. The combustion process was simulated by thermogravimetry and the synthesized powder was characterized using transmission electron microscopy, diffuse reflectance UV/Vis spectroscopy, X-ray diffraction, surface area measurements, and X-ray photoelectron spectroscopy. Tauc plots derived from the diffuse reflectance data yielded an optical band gap of 2.74 eV. The photocatalytic activity of these nanoparticles was superior to a sample prepared by solid-state synthesis. Mechanistic aspects are finally presented, as are structural models and electronic calculations, using density functional theory (DFT).

  18. Studying radiation hardness of a cadmium tungstate crystal based radiation detector

    NASA Astrophysics Data System (ADS)

    Shtein, M. M.; Smekalin, L. F.; Stepanov, S. A.; Zatonov, I. A.; Tkacheva, T. V.; Usachev, E. Yu

    2016-06-01

    The given article considers radiation hardness of an X-ray detector used in production of non-destructive testing instruments and inspection systems. In the course of research, experiments were carried out to estimate radiation hardness of a detector based on cadmium tungstate crystal and its structural components individually. The article describes a layout of an experimental facility that was used for measurements of radiation hardness. The radiation dose dependence of the photodiode current is presented, when it is excited by a light flux of a scintillator or by an external light source. Experiments were carried out to estimate radiation hardness of two types of optical glue used in detector production; they are based on silicon rubber and epoxy. With the help of a spectrophotometer and cobalt gun, each of the glue samples was measured for a relative light transmission factor with different wavelengths, depending on the radiation dose. The obtained data are presented in a comprehensive analysis of the results. It was determined, which of the glue samples is most suitable for production of detectors working under exposure to strong radiation.

  19. Zirconium tungstate/epoxy nanocomposites: effect of nanoparticle morphology and negative thermal expansivity.

    PubMed

    Wu, Hongchao; Rogalski, Mark; Kessler, Michael R

    2013-10-01

    The ability to tailor the coefficient of thermal expansion (CTE) of a polymer is essential for mitigating thermal residual stress and reducing microcracks caused by CTE mismatch of different components in electronic applications. This work studies the effect of morphology and thermal expansivity of zirconium tungstate nanoparticles on the rheological, thermo-mechanical, dynamic-mechanical, and dielectric properties of ZrW2O8/epoxy nanocomposites. Three types of ZrW2O8 nanoparticles were synthesized under different hydrothermal conditions and their distinct properties were characterized, including morphology, particle size, aspect ratio, surface area, and CTE. Nanoparticles with a smaller particle size and larger surface area led to a more significant reduction in gel-time and glass transition temperature of the epoxy nanocomposites, while a higher initial viscosity and significant shear thinning behavior was found in prepolymer suspensions containing ZrW2O8 with larger particle sizes and aspect ratios. The thermo- and dynamic-mechanical properties of epoxy-based nanocomposites improved with increasing loadings of the three types of ZrW2O8 nanoparticles. In addition, the introduced ZrW2O8 nanoparticles did not negatively affect the dielectric constant or the breakdown strength of the epoxy resin, suggesting potential applications of ZrW2O8/epoxy nanocomposites in the microelectronic insulation industry.

  20. Synthesis of bismuth tungstate (Bi2WO6) nanoflakes and their field emission investigation

    NASA Astrophysics Data System (ADS)

    Kolhe, P. S.; Bankar, P. K.; Gavhane, D. S.; Sonawane, K. M.; Maiti, N.; More, M. A.

    2016-05-01

    The nanoflakes of Bismuth Tungstate (Bi2WO6) were successfully synthesized by a one-step facile hydrothermal route without using any templates or surfactants and field emission investigations of the Bi2WO6 nanoflakes emitter are reported. Structural and morphological analysis of as-synthesized Bi2WO6 nanoflakes has been carried out using X-ray diffraction (XRD) and scanning electron microscope (SEM). Moreover, the field emission characteristics of the Bi2WO6 nanoflakes are found to be superior to the other semiconductor emitters. The synthesized Bi2WO6 nanoflakes emitter delivers current density of ~222.35 μA/cm2 at an applied electric field of ~7.2 V/μm. The emission current stability investigated at pre-set value of ~2 μA is observed to be fairly good. These observed results demonstrate potential candidate of the Bi2WO6 cathode as an electron source for practical applications in vacuum microelectronic device.

  1. ROLE OF TUNGSTEN IN THE AQUEOUS PHASE HYDRODEOXYGENATION OF ETHYLENE GLYCOL ON TUNGSTATED ZIRCONIA SUPPORTED PALLADIUM

    SciTech Connect

    Marin-Flores, Oscar G.; Karim, Ayman M.; Wang, Yong

    2014-11-15

    The focus of the present work was specifically on the elucidation of the role played by tungsten on the catalytic activity and selectivity of tungstated zirconia supported palladium (Pd-mWZ) for the aqueous phase hydrodeoxygenation (APHDO) of ethylene glycol (EG). Zirconia supported palladium (Pd-mZ) was used as reference. The catalysts were prepared via incipient wet impregnation and characterized using X-ray diffraction (XRD), temperature-programmed reduction (TPR), CO pulse chemisorption, CO-DRIFTS, ammonia temperature-programmed desorption (NH3-TPD) and pyridine adsorption. The presence of W results in larger Pd particles on supported Pd catalysts, i.e., 0.9 and 6.1 nm Pd particles are for Pd-mZ and Pd-mWZ, respectively. For comparison purposes, the activity of the catalytic materials used in this work was obtained using a well-defined set of operating conditions. The catalytic activity measurements show that the overall intrinsic activity of Pd particles on mWZ is 1.9 times higher than on mZ. APHDO process appears to be highly favored on Pd-mWZ whereas Pd-mZ exhibits a higher selectivity for reforming. This difference in terms of selectivity seems to be related to the high concentration of Brønsted acid sites and electron-deficient Pd species present on Pd-mWZ.

  2. Vapour phase dehydration of glycerol to acrolein over tungstated zirconia catalysts

    NASA Astrophysics Data System (ADS)

    Rao Ginjupalli, Srinivasa; Mugawar, Sowmya; Rajan N., Pethan; Kumar Balla, Putra; Chary Komandur, V. R.

    2014-08-01

    Tetragonal (TZ) and monoclinic (MZ) polymorphs of zirconia supports were synthesised by sol-gel method followed by variation of the calcination temperature. Tungstated (10 wt% WO3) supported on the zirconia polymorphs were prepared by impregnation method by using ammonium metatungstate precursor. The physico-chemical properties of the calcined catalysts were characterised by X-ray diffraction, UV-vis diffused reflectance spectroscopy, X-ray photoelectron spectroscopy (XPS), surface area and pore size distribution measurements to gain insight into the effect of morphology of the catalyst textural properties, and structure. The surface acidic properties have been determined by NH3 TPD method and also with FT-IR spectra of pyridine adsorption. Vapour phase dehydration of glycerol to acrolein was employed to investigate the catalytic functionalities. Glycerol conversion and acrolein selectivity was mainly dependent on the fraction of moderate acid sites with majority of them are due to Brønsted acidic sites. Monoclinic zirconia based catalysts have shown the highest activity and acrolein selectivity compared to the corresponding tetragonal zirconia catalysts.

  3. Compton profiles and Mulliken's populations of cobalt, nickel and copper tungstates: Experiment and theory

    NASA Astrophysics Data System (ADS)

    Meena, B. S.; Heda, N. L.; Kumar, Kishor; Bhatt, Samir; Mund, H. S.; Ahuja, B. L.

    2016-03-01

    We present the first ever studies on Compton profiles of AWO4 (A=Co, Ni and Cu) using 661.65 keV γ-rays emitted by 137Cs source. The experimental momentum densities have been employed to validate exchange and correlation potentials within linear combination of atomic orbitals (LCAO) method. Density functional theory (DFT) with local density approximation and generalized gradient approximation and also the hybridization of Hartree-Fock and DFT (B3LYP and PBE0) have been considered under LCAO scheme. The LCAO-B3LYP scheme is found to be in better agreement with the experimental data than other approximations considered in this work, suggesting applicability of B3LYP approach in predicting the electronic properties of these tungstates. The Mulliken's population (MP) data show charge transfer from Co/Ni/Cu and W to O atoms. The experimental profiles when normalized to same area show almost similar localization of 3d electrons (in real space) of Ni and Cu which is lower than that of Co in their AWO4 environment.

  4. Numerical simulation of photonic-crystal tellurite-tungstate glass fibres used in parametric fibre devices

    SciTech Connect

    Sokolov, V O; Plotnichenko, V G; Nazaryants, V O; Dianov, Evgenii M

    2006-01-31

    Using the MIT Photonic-Bands Package to calculate fully vectorial definite-mode eigenmodes of Maxwell's equations with periodic boundary conditions in a plane-wave basis, light propagation is simulated in fibres formed by point defects in two-dimensional periodic lattices of cylindrical holes in a glass or of glass tubes. The holes and gaps between tubes are assumed filled with air. Single-site hexagonal and square lattices are considered, which were most often studied both theoretically and experimentally and are used to fabricate silica photonic-crystal fibres. As a defect, a single vacancy is studied - the absent lattice site (one hole in a glass or one of the tubes are filled with the same glass) and a similar vacancy with nearest neighbours representing holes of a larger diameter. The obtained solutions are analysed by the method of effective mode area. The dependences of the effective refractive index and dispersion of the fundamental mode on the geometrical parameters of a fibre are found. The calculations are performed for tellurite-tungstate 80TeO{sub 2}-20WO{sub 3} glass fibres taking into account the frequency dispersion of the refractive index. (optical fibres)

  5. Investigation of oxygen vacancy and photoluminescence in calcium tungstate nanophosphors with different particle sizes

    SciTech Connect

    Li, Yezhou; Wang, Zhaofeng; Sun, Luyi; Wang, Zhilong; Wang, Shiqin; Liu, Xiong; Wang, Yuhua

    2014-02-01

    Highlights: • CaWO{sub 4} nanophosphors with different particle sizes were prepared by hydrothermal processes through controlling the concentration of surfactant. • Green emission band of oxygen vacancy in CaWO{sub 4} nanophosphor was clearly observed upon the irradiation of 350 nm excitation. • The concentration of oxygen vacancy in CaWO{sub 4} nanophosphor could be increased by reducing its size. - Abstract: Calcium tungstate (CaWO{sub 4}) nanophosphors with the particle sizes from 35 to 90 nm were synthesized by a hydrothermal process through exactly controlling the pre-treated conditions. The influence of particle size on oxygen vacancy and photoluminescence properties in CaWO{sub 4} nanophosphors was investigated and discussed. The crystal structure of the CaWO{sub 4} nanophosphors presented a certain level of distortion due to the high concentration of oxygen vacancy. Under 350 nm excitation, a clear green emission aroused by oxygen vacancy was observed. The possible luminescence processes for the matrix and oxygen vacancy were proposed. The luminescence spectra of the nanophosphors revealed that the emission and absorption intensity aroused by oxygen vacancy were both enhanced when the size is decreased. On the basis of the above results, the essential relationship between particle size and oxygen vacancy in CaWO{sub 4} nanophosphors was concluded that the concentration of oxygen vacancy could be increased by reducing its size, which was further confirmed by decay lifetimes.

  6. Photocatalytic generation of syngas using combustion-synthesized silver bismuth tungstate.

    PubMed

    de Tacconi, Norma R; Timmaji, Hari Krishna; Chanmanee, Wilaiwan; Huda, Muhammad N; Sarker, Pranab; Janáky, Csaba; Rajeshwar, Krishnan

    2012-08-27

    Silver bismuth tungstate (AgBiW(2)O(8)) nanoparticles were prepared for the first time by solution combustion synthesis by using the corresponding metal nitrates as the precursor and urea as the fuel. These nanoparticles were subsequently modified with Pt catalyst islands using a photocatalytic procedure and used for the photogeneration of syngas (CO+H(2)). Formic acid was used for this purpose for the in situ generation of CO(2) and its subsequent reduction to CO. In the absence of Pt modification, H(2) was not obtained in the gas products evolved. These results were compared with those obtained with acetic acid in place of formic acid. The combustion process was simulated by thermogravimetry and the synthesized powder was characterized using transmission electron microscopy, diffuse reflectance UV/Vis spectroscopy, X-ray diffraction, surface area measurements, and X-ray photoelectron spectroscopy. Tauc plots derived from the diffuse reflectance data yielded an optical band gap of 2.74 eV. The photocatalytic activity of these nanoparticles was superior to a sample prepared by solid-state synthesis. Mechanistic aspects are finally presented, as are structural models and electronic calculations, using density functional theory (DFT). PMID:22431409

  7. Characterization of CALET prototype TASC lead tungstate calorimeter using CERN beam test data

    NASA Astrophysics Data System (ADS)

    Javaid, Amir

    2013-04-01

    The CALorimetric Electron Telescope (CALET) is a high-energy cosmic ray experiment that will be placed on the International Space Station in 2014. The primary goals of CALET are to measure the cosmic ray electron spectra from 1 GeV to 20 TeV, gamma rays from 10 GeV to 10 TeV, and protons and nuclei from 10 GeV up to 1000 TeV. The detector consists of three main components: a Charge Detector (CHD), Imaging Calorimeter (IMC), and Total Absorption Calorimeter (TASC). The TASC consists of 192 lead tungstate (PbWO4) logs arranged in 12 layers. An understanding of the major characteristics of the TASC is important for accurately determining the incident particle shower energy deposition. In September 2012, a prototype CALET detector was exposed to electron, muon, and proton beams from the Super Proton Synchrotron (SPS) at CERN. Muon beams can be used to determine the detector response to minimum ionizing particles (MIP). In the present paper, we discuss the response of the TASC logs to muon beams as a function of position, and signal attenuation during propagation. Included is a discussion of parameterizations of position-dependent muon energy deposition and signal attenuation functions for the TASC logs based on the CERN beam test data.

  8. Hydrothermal synthesis of bi-functional nanostructured manganese tungstate catalysts for selective oxidation.

    PubMed

    Li, Xuan; Lunkenbein, Thomas; Kröhnert, Jutta; Pfeifer, Verena; Girgsdies, Frank; Rosowski, Frank; Schlögl, Robert; Trunschke, Annette

    2016-07-01

    The mechanism of C-H activation in selective oxidation reactions of short-chain alkane molecules over transition metal oxides is critically affected by the balance of acid-base and redox sites at the surface of the catalyst. Using the example of manganese tungstate we discuss how the relative abundance of these sites can be controlled via synthetic techniques. Phase-pure catalysts composed of the thermodynamic stable monoclinic MnWO4 phase have been prepared using hydrothermal synthesis. Variation of the initial pH value resulted in rod-shaped nano-crystalline MnWO4 catalysts composed of particles with varying aspect ratio. The synthesis products have been analysed using transmission electron microscopy, X-ray diffraction, infrared, and photoelectron spectroscopy. In situ Raman spectroscopy was used to investigate the dissolution-re-crystallization processes occurring under hydrothermal conditions. Ethanol oxidation was applied to probe the surface functionalities in terms of acid-base and redox properties. Changes in the aspect ratio of the primary catalyst particles are reflected in the product distribution induced by altering the fraction of acid-base and redox sites exposed at the surface of the catalysts in agreement with the proposed mechanism of particle growth by re-crystallization during ageing under hydrothermal conditions. PMID:27076100

  9. Theoretical study on the gas phase reaction of acrylonitrile with a hydroxyl radical.

    PubMed

    Sun, Jingyu; Wang, Rongshun; Wang, Baoshan

    2011-10-01

    The mechanism and kinetics of the reaction of acrylonitrile (CH(2)=CHCN) with hydroxyl (OH) has been investigated theoretically. This reaction is revealed to be one of the most significant loss processes of acrylonitrile. BHandHLYP and M05-2X methods are employed to obtain initial geometries. The reaction mechanism conforms that OH addition to C[double bond, length as m-dash]C double bond or C atom of -CN group to form the chemically activated adducts, 1-IM1(HOCH(2)=CHCN), 2-IM1(CH(2)=HOCHCN), and 3-IM1(CH(2)=CHCOHN) via low barriers, and direct hydrogen abstraction paths may also occur. Temperature- and pressure-dependent rate constants have been evaluated using the Rice-Ramsperger-Kassel-Marcus theory. The calculated rate constants are in good agreement with the experimental data. At atmospheric pressure with N(2) as bath gas, 1-IM1(OHCH(2)=CHCN) formed by collisional stabilization is the major product in the temperature range of 200-1200 K. The production of CH(2)CCN and CHCHCN via hydrogen abstractions becomes dominant at high temperatures (1200-3000 K).

  10. Sensitive detection of acrolein and acrylonitrile with a pulsed quantum-cascade laser

    NASA Astrophysics Data System (ADS)

    Manne, J.; Lim, A.; Tulip, J.; Jäger, W.

    2012-05-01

    We report on spectroscopic measurements of acrolein and acrylonitrile at atmospheric pressure using a pulsed distributed feedback quantum-cascade laser in combination with intra- and inter-pulse techniques and compare the results. The measurements were done in the frequency region around 957 cm-1. In the inter-pulse technique, the laser is excited with short current pulses (5-10 ns), and the pulse amplitude is modulated with an external current ramp resulting in a ˜2.3 cm-1 frequency scan. In the intra-pulse technique, a linear frequency down-chirp during the pulse is used for sweeping across the absorption line. Long current pulses up to 500 ns were used for these measurements which resulted in a spectral window of ˜2.2 cm-1 during the down-chirp. These comparatively wide spectral windows facilitated the measurements of the relatively broad absorption lines (˜1 cm-1) of acrolein and acrylonitrile. The use of a room-temperature mercury-cadmium-telluride detector resulted in a completely cryogen-free spectrometer. We demonstrate ppb level detection limits within a data acquisition time of ˜10 s with these methodologies.

  11. Two-dimensional spectra of electron collisions with acrylonitrile and methacrylonitrile reveal nuclear dynamics

    SciTech Connect

    Regeta, K. Allan, M.

    2015-05-14

    Detailed experimental information on the motion of a nuclear packet on a complex (resonant) anion potential surface is obtained by measuring 2-dimensional (2D) electron energy loss spectra. The cross section is plotted as a function of incident electron energy, which determines which resonant anion state is populated, i.e., along which normal coordinate the wave packet is launched, and of the electron energy loss, which reveals into which final states each specific resonant state decays. The 2D spectra are presented for acrylonitrile and methacrylonitrile, at the incident energy range 0.095-1.0 eV, where the incoming electron is temporarily captured in the lowest π{sup ∗} orbital. The 2D spectra reveal selectivity patterns with respect to which vibrations are excited in the attachment and de-excited in the detachment. Further insight is gained by recording 1D spectra measured along horizontal, vertical, and diagonal cuts of the 2D spectrum. The methyl group in methacrylonitrile increases the resonance width 7 times. This converts the sharp resonances of acrylonitrile into boomerang structures but preserves the essence of the selectivity patterns. Selectivity of vibrational excitation by higher-lying shape resonances up to 8 eV is also reported.

  12. Structural and optical characterization of metal tungstates (MWO4; M=Ni, Ba, Bi) synthesized by a sucrose-templated method

    PubMed Central

    2013-01-01

    Background Metal tungstates have attracted much attention due to their interesting structural and photoluminescence properties. Depending on the size of the bivalent cation present, the metal tungstates will adopt structures with different phases. In this work, three different phases of metal tungstates MWO4 (M= Ba, Ni and Bi) were synthesized via the sucrose templated method. Results The powders of BaWO4 (tetragonal), NiWO4 (monoclinic) and Bi2WO6 (orthorhombic) formed after calcination temperatures of 750, 650 and 600°C for 4 h respectively are found to be crystalline and exist in their pure phase. Based on Scherrer estimation, their crystallite size are of nanosized. BET results showed NiWO4 has the highest surface area. BaWO4 exhibited less Raman vibrations than the NiWO4 because of the increased lattice symmetry but Bi2WO6 showed almost the same Raman vibrations as BaWO4. From the UV-vis spectra, the band gap transition of the metal tungstates are of the order of BaWO4 > Bi2WO6 > NiWO4. Broad blue-green emission peaks were detected in photoluminescence spectra and the results showed the great dependence on morphology, crystallinity and size of the metal tungstates. Conclusion Three different phases of metal tungstates of BaWO4 (scheelite), NiWO4 (wolframite) and Bi2WO6 (perovskite layer) in their pure phase were successfully prepared by the simple and economical sucrose-templated method. The highest surface area is exhibited by NiWO4 while largest band gap is shown by BaWO4. These materials showed promising optical properties. PMID:23634962

  13. Cation–cation interactions and cation exchange in a series of isostructural framework uranyl tungstates

    SciTech Connect

    Balboni, Enrica; Burns, Peter C.

    2014-05-01

    treatments. The framework of these compounds is robust to cation exchange and heat. (yellow polyhedra=uranium pentagonal bipyramids; blue polyhedra=tungsten octahedral, purple balls=K; yellow balls=Na; grey balls=Tl). - Highlights: • Five isostructural uranyl tungstates compounds were synthesized hydrothermally. • The structures consist of a chains of uranium and tungstate polyhedral. • Chains are connected into a framework by cation–cation interactions. • Cation exchange does not alter the structural integrity of the compounds. • Cation exchange was successful at room temperature and mild hydrothermal conditions.

  14. Ultrasonic velocity and absorption study of binary mixtures of cyclohexane with acrylonitrile by interferometric method at different frequencies

    NASA Astrophysics Data System (ADS)

    Pawar, N. R.; Chimankar, O. P.; Bhandakkar, V. D.; Padole, N. N.

    2012-12-01

    The ultrasonic velocity (u), absorption (α), density (ρ), and viscosity (η) has been measured at different frequencies (1MHz to 10MHz) in the binary mixtures of cyclohexane with acrylonitriile over the entire range of composition at temperature 303K. Vander Waal's constant (b), adiabatic compressibility (βa), acoustic impedance (Z), molar volume (V), free length (Lf), free volume, internal pressure, intermolecular radius and relative association have been also calculated. A special application for acrylonitrile is in the manufacture of carbon fibers. These are produced by paralysis of oriented poly acrylonitrile fibers and are used to reinforce composites for high-performance applications in the aircraft, defense and aerospace industries. Other applications of acrylonitrile are in the production of fatty amines, ion exchange resins and fatty amine amides used in cosmetics, adhesives, corrosion inhibitors and water-treatment resins. Cyclohexane derivatives can be used for the synthesis of pharmaceuticals, dyes, herbicides, plant growth regulator, plasticizers, rubber chemicals, nylon, cyclamens and other organic compounds. In the view of these extensive applications of acrylonitrile and cyclohexane in the engineering process, textile and pharmaceutical industries present study provides qualitative information regarding the nature and strength of interaction in the liquid mixtures through derive parameters from ultrasonic velocity and absorption measurement.

  15. Monocrystal Elastic Constants of the Negative-Thermal-Expansion Compound Zirconium Tungstate (ZrW2O8)

    NASA Astrophysics Data System (ADS)

    Drymiotis, F. R.; Ledbetter, H.; Betts, J. B.; Kimura, T.; Lashley, J. C.; Migliori, A.; Ramirez, A. P.; Kowach, G. R.; van Duijn, J.

    2004-07-01

    We measured zirconium tungstate's elastic constants Cij. This compound shows relatively soft, nearly isotropic elastic constants with normal Poisson ratios and no approach to Born instability. ZrW2O8 shows normal ambient-temperature elastic constants Cij, but remarkable dCij/dT that show dominant low-frequency acoustic-vibration modes. From the bulk modulus, we estimated the total ambient-temperature thermodynamic Grüneisen parameter as γ=-1.2. The dB/dT slope gives a Grüneisen parameter γ=-7. The 300 0K bulk-modulus increase (40%) seems unprecedented and breaks Birch's law of corresponding states.

  16. Surface Raman excitation and enhancement profiles for chromate, molybdate, and tungstate on colloidal silver

    SciTech Connect

    Feilchenfeld, H.; Siiman, O.

    1986-05-08

    The surface-enhanced Raman scattering (SERS) excitation profiles of chromate, molybdate, and tungstate ions on colloidal silver were obtained by using excitation wavelengths between 457.9 and 676.4 nm. The intensity of the strongest SERS band between 800 and 900 cm/sup -1/, assignable to nu/sub s/(M-O), was in each case referenced to the 1020-cm/sup -1/ band of the internal standard, methanol, in silver hydrosols. These relative SERS intensities were compared against similar intensity ratios for each oxo anion in solution and then appropriately scaled for the concentration of MO/sub 4//sup 2 -/ in solution and on the surface of the silver particles in the sols. Peak SERS enhancements occurred at 560 nm for CrO/sub 4//sup 2 -/ and at 600 nm for both MoO/sub 4//sup 2 -/ and WO/sub 4//sup 2 -/. The latter peak positions matched the secondary absorption band maxima that originate from aggregates of silver particles in the sols. The numerical values of the SERS enhancements were 5 x 10/sup 4/-l x 10/sup 5/ for CrO/sub 4//sup 2 -/, 9 x 10/sup 5/ for MoO/sub 4//sup 2 -/, and about 2 x 10/sup 5/ for WO/sub 4//sup 2 -/ on colloidal silver. The somewhat lower SERS enhancements for the chromophoric adsorbate, CrO/sub 4//sup 2 -/, which adsorbs maximally at 370 nm in aqueous solution, are attributed to a lower degree of aggregation for the sols with added CrO/sub 4//sup 2 -/, rather than to partial quenching of its resonant excited state on the heavy metal (silver) surface. 34 references, 4 figures, 5 tables.

  17. Performance characterization of a MVCT scanner using multislice thick, segmented cadmium tungstate-photodiode detectors

    SciTech Connect

    Kirvan, P. F.; Monajemi, T. T.; Fallone, B. G.; Rathee, S.

    2010-01-15

    Purpose: Megavoltage computed tomography (MVCT) and megavoltage cone beam computed tomography (MVCBCT) can be used for visualizing anatomical structures prior to radiation therapy treatments to assist in patient setup and target localization. These systems are less susceptible to metal artifacts and provide better CT number linearity than conventional CT scanners. However, their contrast is limited by the properties of the megavoltage photons and the low detective quantum efficiency (DQE) of flat panel detector systems currently available. By using higher DQE, thick, segmented cadmium tungstate detectors, the authors can improve the low contrast detectability of a MVCT system. This in turn would permit greater soft tissue visualization for a given radiation dose, allowing MVCT to be used in more clinical situations. Methods: This article describes the evaluation of our prototype system that uses thick, segmented detectors. In order to create images using a dose that would be acceptable for day to day patient imaging, the authors evaluated their system using the low intensity bremsstrahlung component of a 6 MeV electron beam. The system was evaluated for its uniformity, high contrast resolution, low contrast detectability, signal to noise ratio, contrast to noise ratio, and CT number linearity. Results: The prototype system was found to have a high contrast spatial resolution of about 5 line pairs per cm, and to be able to visualize a 15 mm 1.5% contrast target with 2 cGy of radiation dose delivered. SNR{sup 2} vs radiation dose and mean pixel value vs electron density curves were linear. Conclusions: This prototype system shows a large improvement in low contrast detectability over current MVCBCT systems.

  18. In-situ growth of zinc tungstate nanorods on graphene for enhanced photocatalytic performance

    SciTech Connect

    Rao, Lei; Xu, Junling; Ao, Yanhui; Wang, Peifang

    2014-09-15

    Graphical abstract: Graphene/ZnWO{sub 4} (G–ZnWO{sub 4}) nanorod composite photocatalysts were prepared by a simple one-step method. Namely, the reduction of graphene oxide and the growth of ZnWO{sub 4} nanorod occurred simultaneously in one single process. An enhancement in the photocatalytic activities were observed in G–ZnWO{sub 4} composites compared with pure ZnWO{sub 4} under UV light irradiation. - Highlights: • Graphene–ZnWO{sub 4} composite photocatalyst was prepared for the first time. • The as-prepared composite photocatalysts show high activity for dye degradation. • Effect of graphene amount on the photocatalytic activity was investigated. - Abstract: Graphene–zinc tungstate (G–ZnWO{sub 4}) hybrid photocatalysts were prepared by an in-situ growth method in which the reduction of graphene oxide (GO) and the growth of ZnWO{sub 4} crystals occurred simultaneously. The materials were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV–vis diffuse reflectance spectroscopy and X-ray photoelectron spectroscopy. The photocatalytic activity was investigated by the degradation of dye methylene blue (MB). An enhancement in the photocatalytic activity was observed for G–ZnWO{sub 4} hybrids compared with pure ZnWO{sub 4} under UV light. This improvement was attributed to the following two reasons: increased migration efficiency of photo-induced electrons and increased adsorption activity for dye molecules. The effect of the amount of graphene on the photocatalytic activity was also investigated. Results showed that there was an optimum amount of 2%.

  19. Structural, microstructural and vibrational analyses of the monoclinic tungstate BiLuWO{sub 6}

    SciTech Connect

    Ait Ahsaine, H.; Taoufyq, A.; Patout, L.; Ezahri, M.; Benlhachemi, A.; Bakiz, B.; Villain, S.; Guinneton, F.; Gavarri, J.-R.

    2014-10-15

    The bismuth lutetium tungstate phase BiLuWO{sub 6} has been prepared using a solid state route with stoichiometric mixtures of oxide precursors. The obtained polycrystalline phase has been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy. In the first step, the crystal structure has been refined using Rietveld method: the crystal cell was resolved using monoclinic system (parameters a, b, c, β) with space group A2/m. SEM images showed the presence of large crystallites with a constant local nominal composition (BiLuW). TEM analyses showed that the actual local structure could be better represented by a superlattice (a, 2b, c, β) associated with space groups P2 or P2/m. The Raman spectroscopy showed the presence of vibrational bands similar to those observed in the compounds BiREWO{sub 6} with RE=Y, Gd, Nd. However, these vibrational bands were characterized by large full width at half maximum, probably resulting from the long range Bi/Lu disorder and local WO{sub 6} octahedron distortions in the structure. - Graphical abstract: The average structure of BiLuWO{sub 6} determined from X-ray diffraction data can be represented by A2/m space group. Experimental Electron Diffraction patterns along the [0vw] zone axes of the monoclinic structure and associated simulated patterns show the existence of a monoclinic superstructure with space group P2 or P2/m. - Highlights: • A new monoclinic BiLuWO{sub 6} phase has been elaborated from solid-state reaction. • The space group of the monoclinic disordered average structure should be A2/m. • Transmission electron microscopy leads to a superlattice with P2/m space group. • Raman spectroscopy suggests existence of local disorder.

  20. Prevention of acrylonitrile-induced gastrointestinal bleeding by sulfhydryl compounds, atropine and cimetidine

    SciTech Connect

    Ghanayem, B.I.; Ahmed, A.E.

    1986-07-01

    We have recently demonstrated that acrylonitrile (VCN) causes acute gastric hemorrhage and mucosal erosions. The current studies were undertaken to investigate the effects of the sulfhydryl-containing compounds, cysteine and cysteamine, the cholinergic blocking agent atropine and the histamine H2 receptor antagonist, cimetidine on the VCN-induced gastrointestinal (GI) bleeding in rats. Our data shows that pretreatment with L-cysteine, cysteamine, atropine or cimetidine has significantly protected rats against the VCN-induced GI bleeding. A possible mechanism of the VCN-induced GI bleeding may involve the interaction of VCN with critical sulfhydryl groups that, in turn, causes alteration of acetylcholine muscarinic receptors to lead to gastric hemorrhagic lesions and bleeding.

  1. Studies of plastic crystal gel polymer electrolytes based on poly(vinylidene chloride-co-acrylonitrile)

    NASA Astrophysics Data System (ADS)

    Hambali, D.; Zainuddin, Z.; Supa'at, I.; Osman, Z.

    2016-02-01

    In this work, we have prepared systems of poly(vinylidene chloride-co-acrylonitrile) (PVdC-co-AN) based gel polymer electrolytes (GPEs) which are single plasticized-GPEs and double plasticized-GPEs. Both systems comprised plastic crystal succinonitrile SN to form plastic crystal gel polymer electrolyte (PGPE) films. The ionic conductivity of the PGPE films were analysed by means of a.c. impedance spectroscopy at room temperature as well as at the temperature range of 303 K to 353 K. The temperature dependence ionic conductivity was found to obey the VTF rule. To study the interactions among the constituents in the PGPEs, Fourier Transform Infrared Spectroscopy (FTIR) was carried out and hence, the complexation between them has also been confirmed.

  2. Preparing cellulose nanocrystal/acrylonitrile-butadiene-styrene nanocomposites using the master-batch method.

    PubMed

    Ma, Libo; Zhang, Yang; Meng, Yujie; Anusonti-Inthra, Phuriwat; Wang, Siqun

    2015-07-10

    The master-batch method provides a simple way to apply cellulose nanocrystal (CNC) as reinforcement in a hydrophobic matrix. The two-stage process includes making high-CNC content (70 wt%) master batch pellets, then mixing acrylonitrile-butadiene-styrene (ABS) and maleic anhydride grafted polyethylene with the master batch pellets to prepare the ABS/CNC nanocomposite in extruder. SEM image indicates that self-assembled CNC nanosheets disperse evenly throughout the polymer matrix. The improved mechanical properties shown in tensile and DMA tests reveal that the CNC combines well with the ABS. TGA results show that the thermal degradation temperature of CNC in the master batch increases because of the protection of the ABS coating. This approach not only improves the dispersion ability and the thermal stability of CNC, but it is also applicable to use with other hydrophobic thermoplastics in industrial scale production.

  3. Gloves against mineral oils and mechanical hazards: composites of carboxylated acrylonitrile-butadiene rubber latex.

    PubMed

    Krzemińska, Sylwia; Rzymski, Władysław M; Malesa, Monika; Borkowska, Urszula; Oleksy, Mariusz

    2016-09-01

    Resistance to permeation of noxious chemical substances should be accompanied by resistance to mechanical factors because the glove material may be torn, cut or punctured in the workplace. This study reports on glove materials, protecting against mineral oils and mechanical hazards, made of carboxylated acrylonitrile-butadiene rubber (XNBR) latex. The obtained materials were characterized by a very high resistance of the produced materials to oil permeation (breakthrough time > 480 min). The mechanical properties, and especially tear resistance, of the studied materials were improved after the addition of modified bentonite (nanofiller) to the XNBR latex mixture. The nanocomposite meets the requirements in terms of parameters characterizing tear, abrasion, cut and puncture resistance. Therefore, the developed material may be used for the production of multifunctional protective gloves. PMID:26757889

  4. Chemical characterization of CTBN (carboxyl-terminated butadiene/acrylonitrile) and its epoxy adduct

    SciTech Connect

    Smith, R.E.

    1990-01-01

    This report describes the analysis of carbonxyl-terminated butadiene (CTB), carboxyl-terminated butadiene/acrylonitrile (CTBN), and a CTBN adduct prepared by reaction with Epon 828. Data from gel permeation chromatography, nuclear magnetic resonance spectroscopy, high performance liquid chromatography, and ion chromatography are presented and discussed. Quantitative methods based on carbon-13 and proton NMR for analyzing CTBN are described. Proton NMR was found to be useful in identifying lots that have an abnormal amount of CTBN protons. One such lot exhibited a phase separation of a polybutadiene impurity. Carbon-13 NMR was found to be capable of determining nitrile content directly. Carbon-13 NMR had a relative standard deviation of 8.3% and a proton NMR of 3.9%. Proton NMR was found to be useful in identifying lots that have 5% more CTBN protons than other lots. 3 refs., 11 figs., 4 tabs.

  5. Synthesis and flocculation properties of gum ghatti and poly(acrylamide-co-acrylonitrile) based biodegradable hydrogels.

    PubMed

    Mittal, Hemant; Jindal, Rajeev; Kaith, Balbir Singh; Maity, Arjun; Ray, Suprakas Sinha

    2014-12-19

    This article reports the development of biodegradable flocculants based on graft co-polymers of gum ghatti (Gg) and a mixture of acrylamide and acrylonitrile co-monomers (AAm-co-AN). The hydrogel polymer exhibited an excellent swelling capacity of 921% in neutral medium at 60°C. The polymer was used to remove saline water from various petroleum fraction-saline water emulsions. The flocculation characteristics of the hydrogel polymer were studied in turbid kaolin solution as a function of the amount of polymer and the solution temperature and pH. Biodegradation studies of hydrogel polymer were conducted using the soil composting method, and the degradation process was constantly monitored using scanning electron microscopy and Fourier transform infrared spectroscopy techniques. The results demonstrated an 89.47% degradation of the polymer after 60 days. Finally, the hydrogel polymer adsorbed 98% of cationic dyes from the aqueous solutions.

  6. Dielectric Relaxation Behavior of Poly(acrylonitrile-co-methacrylonitrile) Microcapsules Dispersed in a Silicone Matrix

    NASA Technical Reports Server (NTRS)

    Park, Taigyoo; OBrien, Emmett; Lizotte, Jeremy R.; Glass, Thomas E.; Ward, Thomas C.; Long, Timothy E.; Leo, Donald J.

    2006-01-01

    The dielectric relaxation behavior of poly(acrylonitrile-co-methacrylonitrile) dispersed in a cured polydimethyl siloxane (PDMS) matrix as microcapsules was investigated over multiple thermal cycles and at varying concentrations. The copolymer microcapsules contained an isopentane core. In the PDMS matrix this copolymer displayed a pronounced relaxation signal at temperatures above the glass transition of the copolymers due to Maxwell-Wagner-Sillars (MWS) relaxation. The mechanism of MWS relaxation interpreted by the Havriliak-Negami and Kohlrausch-Williams-Watts relaxation functions was found to be very similar to previous studies of neat polyacrylonitrile and its copolymer. The activation energy of the relaxation decreased over successive thermal cycling coincident with a decreasing strength of the relaxation. These observations were attributed to the decreasing concentration of nitrile groups due to intramolecular cyclizations.

  7. Synthesis, characterization, and antimicrobial activity of poly(acrylonitrile-co-methyl methacrylate) with silver nanoparticles.

    PubMed

    El-Aassar, M R; Hafez, Elsayed E; Fouda, Moustafa M G; Al-Deyab, Salem S

    2013-10-01

    Nanotechnology is expected to open some new aspects to fight and prevent diseases using atomic-scale tailoring of materials. The main aim of this study is to biosynthesize silver nanoparticles (AgNPs) using Trichoderma viride (HQ438699); the metabolite of this fungus will help either in reduction of the silver nitrate-adding active materials which will be loaded on the surface of the produced AgNPs. Poly(acrylonitrile-co-methyl methacrylate) copolymer (poly (AN-co-MMA)) was grafted with the prepared AgNPs. The poly(AN-co-MMA)/AgNPs were examined against ten different pathogenic bacterial strains, and the result was compared with another four different generic antibiotics. The produced poly(AN-co-MMA)/AgNPs showed high antibacterial activity compared with the four standard antibiotics. Moreover, the grafting of these AgNPs into the copolymer has potential application in the biomedical field. PMID:23873643

  8. Experimental study on behaviors of dielectric elastomer based on acrylonitrile butadiene rubber

    NASA Astrophysics Data System (ADS)

    An, Kuangjun; Chuc, Nguyen Huu; Kwon, Hyeok Yong; Phuc, Vuong Hong; Koo, Jachoon; Lee, Youngkwan; Nam, Jaedo; Choi, Hyouk Ryeol

    2010-04-01

    Previously, the dielectric elastomer based on Acrylonitrile Butadiene Rubber (NBR), called synthetic elastomer has been reported by our group. It has the advantages that its characteristics can be modified according to the requirements of performances, and thus, it is applicable to a wide variety of applications. In this paper, we address the effects of additives and vulcanization conditions on the overall performance of synthetic elastomer. In the present work, factors to have effects on the performances are extracted, e.g additives such as dioctyl phthalate (DOP), barium titanium dioxide (BaTiO3) and vulcanization conditions such as dicumyl peroxide (DCP), cross-linking times. Also, it is described how the performances can be optimized by using DOE (Design of Experiments) technique and experimental results are analyzed by ANOVA (Analysis of variance).

  9. Synthesis and flocculation properties of gum ghatti and poly(acrylamide-co-acrylonitrile) based biodegradable hydrogels.

    PubMed

    Mittal, Hemant; Jindal, Rajeev; Kaith, Balbir Singh; Maity, Arjun; Ray, Suprakas Sinha

    2014-12-19

    This article reports the development of biodegradable flocculants based on graft co-polymers of gum ghatti (Gg) and a mixture of acrylamide and acrylonitrile co-monomers (AAm-co-AN). The hydrogel polymer exhibited an excellent swelling capacity of 921% in neutral medium at 60°C. The polymer was used to remove saline water from various petroleum fraction-saline water emulsions. The flocculation characteristics of the hydrogel polymer were studied in turbid kaolin solution as a function of the amount of polymer and the solution temperature and pH. Biodegradation studies of hydrogel polymer were conducted using the soil composting method, and the degradation process was constantly monitored using scanning electron microscopy and Fourier transform infrared spectroscopy techniques. The results demonstrated an 89.47% degradation of the polymer after 60 days. Finally, the hydrogel polymer adsorbed 98% of cationic dyes from the aqueous solutions. PMID:25263897

  10. Preparing cellulose nanocrystal/acrylonitrile-butadiene-styrene nanocomposites using the master-batch method.

    PubMed

    Ma, Libo; Zhang, Yang; Meng, Yujie; Anusonti-Inthra, Phuriwat; Wang, Siqun

    2015-07-10

    The master-batch method provides a simple way to apply cellulose nanocrystal (CNC) as reinforcement in a hydrophobic matrix. The two-stage process includes making high-CNC content (70 wt%) master batch pellets, then mixing acrylonitrile-butadiene-styrene (ABS) and maleic anhydride grafted polyethylene with the master batch pellets to prepare the ABS/CNC nanocomposite in extruder. SEM image indicates that self-assembled CNC nanosheets disperse evenly throughout the polymer matrix. The improved mechanical properties shown in tensile and DMA tests reveal that the CNC combines well with the ABS. TGA results show that the thermal degradation temperature of CNC in the master batch increases because of the protection of the ABS coating. This approach not only improves the dispersion ability and the thermal stability of CNC, but it is also applicable to use with other hydrophobic thermoplastics in industrial scale production. PMID:25857992

  11. A flexible Li polymer primary cell with a novel gel electrolyte based on poly(acrylonitrile)

    NASA Astrophysics Data System (ADS)

    Akashi, Hiroyuki; Tanaka, Ko-ichi; Sekai, Koji

    The performance of a Li polymer primary cell with fire-retardant poly(acrylonitrile) (PAN)-based gel electrolytes is reported. By optimizing electrodes, electrolytes, the packaging material, and the structural design of the polymer cell, we succeeded in developing a "film-like" Li polymer primary cell with sufficient performance for practical use. The cell is flexible and less than 0.5 mm thick, which makes it suitable for a power source for some smart devices, such as an IC card. Fast cation conduction in the gel electrolyte minimizes the drop of the discharge capacity even at -20 °C. The high chemical stability of the gel electrolytes and the new packaging material allow the self-discharge rate to be limited to under 4.3%, which is equivalent to that of conventional coin-shaped or cylindrical Li-MnO 2 cells.

  12. Improved procedure for determination of acrylonitrile in foods and its application to meat.

    PubMed

    Page, B D; Charbonneau, C F

    1985-01-01

    The previously described headspace-gas chromatographic procedure for the determination of acrylonitrile (AN) in several foods, with N/P selective detection, has been modified to include packaged luncheon meats. The loss of AN during equilibration at 100 degrees C in meat samples as well as the previously described loss in cold pack cheese and peanut butter has been studied. The loss of AN could be prevented by the addition of 10% phosphoric acid, which increases the acidity of the food-acid-salt slurry to pH 1.2-1.5. This acidification permits detection of AN at 2 ppb (5% FSD at 16 X 10(-2) amp/mV) in all foods studied. AN was not detected in 10 samples of luncheon meat packaged in AN-based plastic which contained up to 2.6 ppm AN.

  13. Selection and preliminary evaluation of three structures as potential solid conductors of alkali ions: Two hollandites, a titanate, and a tungstate

    NASA Technical Reports Server (NTRS)

    Singer, J.; Kautz, H. E.; Fielder, W. L.; Fordyce, J. S.

    1973-01-01

    Utilization of crystal-chemical criteria has suggested three structure types in which alkali ions may be mobile: (1)hollandites K(x)Mg(x/2)Ti(8-x/2)O16 and K(x)Al(x)Ti(8-x)O16 for 1.6 less than or equal to x less than or equal to 2.0 tungstate K2W4013; and (3) sodium hexatitante Na2Ti6O13. Each is a tunnel structure. An electrical screening procedure, previously tested on beta-alumina, has indicated high K(+) ion mobility in the hollandites and in the tungstate, but not in the hexatitanate. Specimens were polycrystalline disks near 90 percent of theoretical density. The ac conductivity calculated from dielectric and capacitance measurements has been attributed to ion mobility. This ac conductivity was up to 0.01/ohm-cm for hollandites and about 0.0001/ohm-cm for the tungstate, with approximate activation energies of 21 to 25 and 16 kJ/mole (5 to 6 and 4 kcal/mole), respectively. Electronic conduction and chemical reactivity have eliminated the tungstate from further consideration. The hollandites have been considered worthy of further development and evaluation.

  14. Perinatal Toxicity and Carcinogenicity Studies of Styrene –Acrylonitrile Trimer, A Ground Water Contaminant

    PubMed Central

    Behl, Mamta; Elmore, Susan A.; Malarkey, David E.; Hejtmancik, Milton R.; Gerken, Diane K.; Chhabra, Rajendra S.

    2015-01-01

    Styrene Acrylonitrile (SAN) Trimer is a by-product in the production of acrylonitrile styrene plastics. Following a report of a childhood cancer cluster in the Toms River section of Dover Township, New Jersey, SAN Trimer was identified as one of the groundwater contaminants at Reich Farm Superfund site in the township. The contaminants from the Reich Farm site’s ground water plume impacted two wells at the Parkway well field. The National Toxicology Program (NTP) studied the toxicity and carcinogenicity of SAN Trimer in rats exposed during their perinatal developmental period and adulthood. The chronic toxicity and carcinogenicity studies in F344/N rats were preceded by 7- and 18-week perinatal toxicity studies to determine the exposure concentrations for the 2-year studies. Subsequently, Fisher 344 pregnant dams were exposed to SAN Trimer containing diet at 400, 800, or 1600 ppm concentrations during gestation, nursing and weaning periods of offspring followed by two year of adult exposures to both male and female pups. There was no statistically significant evidence of carcinogenic activity following SAN-Trimer exposure; however, rare neoplasms in the brain and spinal cord were observed in males and to lesser extent in female rats. These incidences were considered within the range of historical background in the animal model used in the current studies. Therefore, the presence of a few rarely occurring CNS tumors in the treated groups were not judged to be associated with the SAN Trimer exposure. The major finding was a dose-related peripheral neuropathy associated with the sciatic nerves in females and spinal nerve roots in males and females thereby suggesting that SAN trimer is potentially a nervous system toxicant. PMID:24060431

  15. Photoinitiated decomposition of substituted ethylenes: The photodissociation of vinyl chloride and acrylonitrile at 193 nm

    SciTech Connect

    Blank, D.A.; Suits, A.G.; Lee, Y.T.

    1997-04-01

    Ethylene and its substituted analogues (H{sub 2}CCHX) are important molecules in hydrogen combustion. As the simplest {pi}-bonded hydrocarbons these molecules serve as prototypical systems for understanding the decomposition of this important class of compounds. The authors have used the technique of photofragment translational spectroscopy at beamline 9.0.2.1 to investigate the dissociation of vinyl chloride (X=Cl) and acrylonitrile (X=CN) following absorption at 193 nm. The technique uses a molecular beam of the reactant seeded in helium which is crossed at 90 degrees with the output of an excimer laser operating on the ArF transition, 193.3 nm. The neutral photoproducts which recoil out of the molecular beam travel 15.1 cm where they are photoionized by the VUV undulator radiation, mass selected, and counted as a function of time. The molecular beam source is rotatable about the axis of the dissociation laser. The authors have directly observed all four of the following dissociation channels for both systems: (1) H{sub 2}CCHX {r_arrow} H + C{sub 2}H{sub 2}X; (2) H{sub 2}CCHX {r_arrow} X + C{sub 2}H{sub 3}; (3) H{sub 2}CCHX {r_arrow} H{sub 2} + C{sub 2}HX; and (4) H{sub 2}CCHX {r_arrow} HX + C{sub 2}H{sub 2}. They measured translational energy distributions for all of the observed channels and measured the photoionization onset for many of the photoproducts which provided information about their chemical identity and internal energy content. In the case of acrylonitrile, selective product photoionization provided the ability to discriminate between channels 2 and 4 which result in the same product mass combination.

  16. Covalent immobilization of glucose oxidase onto new modified acrylonitrile copolymer/silica gel hybrid supports.

    PubMed

    Godjevargova, Tzonka; Nenkova, Ruska; Dimova, Nedyalka

    2005-08-12

    New polymer/silica gel hybrid supports were prepared by coating high surface area of silica gel with modified acrylonitrile copolymer. The concentrations of the modifying agent (NaOH) and the modified polymer were varied. GOD was covalently immobilized on these hybrid supports and the relative activity and the amount of bound protein were determined. The highest relative activity and sufficient amount of bound protein of the immobilized GOD were achieved in 10% NaOH and 2% solution of modified acrylonitrile copolymer. The influence of glutaraldehyde concentration and the storage time on enzyme efficiency were examined. Glutaraldehyde concentration of 0.5% is optimal for the immobilized GOD. It was shown that the covalently bound enzyme (using 0.5% glutaraldehyde) had higher relative activity than the activity of the adsorbed enzyme. Covalently immobilized GOD with 0.5% glutaraldehyde was more stable for four months in comparison with the one immobilized on pure silica gel, hybrid support with 10% glutaraldehyde and the free enzyme. The effect of the pore size on the enzyme efficiency was studied on four types of silica gel with different pore size. Silica with large pores (CPC-Silica carrier, 375 A) presented higher relative activity than those with smaller pore size (Silica gel with 4, 40 and 100 A). The amount of bound protein was also reduced with decreasing the pore size. The effect of particle size was studied and it was found out that the smaller the particle size was, the greater the activity and the amount of immobilized enzyme were. The obtained results proved that these new polymer/silica gel hybrid supports were suitable for GOD immobilization. PMID:16080168

  17. (Z)-3-(1H-Indol-3-yl)-2-(3-thienyl)acrylonitrile and (Z)-3-[1-(4-tert-butylbenzyl)-1H-indol-3-yl]-2-(3-thienyl)acrylonitrile.

    PubMed

    Sonar, Vijayakumar N; Parkin, Sean; Crooks, Peter A

    2005-02-01

    (Z)-3-(1H-Indol-3-yl)-2-(3-thienyl)acrylonitrile, C15H10N2S, (I), and (Z)-3-[1-(4-tert-butylbenzyl)-1H-indol-3-yl]-2-(3-thienyl)acrylonitrile, C26H24N2S, (II), were prepared by base-catalyzed reactions of the corresponding indole-3-carboxaldehyde with thiophene-3-acetonitrile. 1H/13C NMR spectral data and X-ray crystal structures of compounds (I) and (II) are presented. The olefinic bond connecting the indole and thiophene moieties has Z geometry in both cases, and the molecules crystallize in space groups P2(1)/c and C2/c for (I) and (II), respectively. Slight thienyl ring-flip disorder (ca 5.6%) was observed and modeled for (I).

  18. Enhanced photorefractive performance in CdSe quantum-dot-dispersed poly(styrene-co-acrylonitrile) polymers

    SciTech Connect

    Li Xiangping; Embden, Joel van; Chon, James W. M.; Gu Min; Evans, Richard A.

    2010-06-21

    This paper reports on the enhanced photorefractive behavior of a CdSe quantum-dot-dispersed less expensive polymer of poly(styrene-co-acrylonitrile). The capability of CdSe quantum dots used as photosensitizers and the associated photorefractive performance are characterized through a photocurrent experiment and a two-beam coupling experiment, respectively. An enhanced two-beam coupling gain coefficient of 12.2 cm{sup -1} at 46 V/mum was observed owning to the reduced potential barrier. The photorefractive performance per CdSe quantum dot is three orders of magnitude higher than that in the sample sensitized by trinitrofluorenone in poly(styrene-co-acrylonitrile), and almost ten times higher than that in the CdSe quantum-dot-sensitized poly(N-vinylcarbazole) polymers.

  19. Antibacterial activity of poly(vinyl alcohol)-b-poly(acrylonitrile) based micelles loaded with silver nanoparticles.

    PubMed

    Bryaskova, Rayna; Pencheva, Daniela; Kyulavska, Mariya; Bozukova, Dimitriya; Debuigne, Antoine; Detrembleur, Christophe

    2010-04-15

    A new amphiphilic poly(vinyl alcohol)-b-poly(acrylonitrile) (PVOH-b-PAN) copolymer obtained by selective hydrolysis of well-defined poly(vinyl acetate)-b-poly(acrylonitrile) copolymer synthesized by cobalt mediated radical polymerization was used for the preparation of PVOH-b-PAN based micelles with embedded silver nanoparticles. The successful formation of silver loaded micelles has been confirmed by UV-vis, DLS and TEM analysis and their antibacterial activity against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa) and spore solution of Bacillus subtilis (B. subtilis) has been studied. PVOH-b-PAN based micelles with embedded silver nanoparticles showed a strong bactericidal effect against E. coli, S. aureus and P. aeruginosa and the minimum bactericidal concentration for each system (MBC) has been determined.

  20. Morphology and Dynamic Mechanical Properties of Diglycidyl Ether of Bisphenol-A Toughened with Carboxyl-Terminated Butadiene-Acrylonitrile

    NASA Technical Reports Server (NTRS)

    Hong, S. D.; Chung, S. Y.; Fedors, R. F.; Moacanin, J.; Gupta, A.

    1984-01-01

    The fracture toughness of an incorporation of a carboxyl-terminated butadiene acrylonitrile (CTBN) elastomer in diglycidyl ether bisphenol A (DGEBA) resin was investigated. Measurements of dynamic mechanical properties, scanning electron microscopy and small-angle X-ray scattering were carried out to characterize the state of cure, morphology and particle size and size distribution of the neat resins and their graphite fiber reinforced composites.

  1. Nanostructured Synthetic Carbons Obtained by Pyrolysis of Spherical Acrylonitrile/Divinylbenzene Copolymers

    PubMed Central

    Malik, Danish J.; Trochimczuk, Andrzej W.; Ronka, Sylwia

    2012-01-01

    Novel carbon materials have been prepared by the carbonization of acrylonitrile (AN)/divinylbenzene (DVB) suspension porous copolymers having nominal crosslinking degrees in the range of 30–70% and obtained in the presence of various amounts of porogens. The carbons were obtained by pre-oxidation of AN/DVB copolymers at 250−350°C in air followed by pyrolysis at 850°C in an N2 atmosphere. Both processes were carried out in one furnace and the resulting material needed no further activation. Resulting materials were characterized by XPS and low temperature nitrogen adsorption/desorption. It was found that maximum pyrolysis yield was ca. 50% depending on the oxidation conditions but almost independent of the crosslinking degree of the polymers. Porous structure of the carbons was characterized for the presence of micropores and macropores, when obtained from highly crosslinked polymers or polymers oxidized at 350°C and meso- and macropores in all other cases. The latter pores are prevailing in the structure of carbons obtained from less porous AN/DVB resins. Specific surface area (BET) of polymer derived carbons can vary between 440 m2/g and 250 m2/g depending on the amount of porogen used in the synthesis of the AN/DVB polymeric precursors. PMID:22916245

  2. An investigation on chloroprene-compatibilized acrylonitrile butadiene rubber/high density polyethylene blends.

    PubMed

    Ahmed, Khalil

    2015-11-01

    Blends of acrylonitrile butadiene rubber/high density polyethylene (NBR/HDPE) compatibilized by Chloroprene rubber (CR) were prepared. A fixed quantity of industrial waste such as marble waste (MW, 40 phr) was also included. The effect of the blend ratio and CR on cure characteristics, mechanical and swelling properties of MW-filled NBR/HDPE blends was investigated. The results showed that the MW-filled NBR/HDPE blends revealed an increase in tensile strength, tear, modulus, hardness and cross-link density for increasing weight ratio of HDPE. The minimum torque (M L) and maximum torque (M H) of blends increased with increasing weight ratio of HDPE while scorch time (ts2) cure time (tc90), compression set and abrasion loss of blends decreased with increasing weight ratio of HDPE. The blends also showed a continuous reduction in elongation at break as well as swelling coefficient with increasing HDPE amount in blends. MW filled blends based on CR provided the most encouraging balance values of overall properties. PMID:26644917

  3. Acrylonitrile Butadiene Styrene (ABS) plastic based low cost tissue equivalent phantom for verification dosimetry in IMRT.

    PubMed

    Kumar, Rajesh; Sharma, S D; Deshpande, Sudesh; Ghadi, Yogesh; Shaiju, V S; Amols, H I; Mayya, Y S

    2009-12-17

    A novel IMRT phantom was designed and fabricated using Acrylonitrile Butadiene Styrene (ABS) plastic. Physical properties of ABS plastic related to radiation interaction and dosimetry were compared with commonly available phantom materials for dose measurements in radiotherapy. The ABS IMRT phantom has provisions to hold various types of detectors such as ion chambers, radiographic/radiochromic films, TLDs, MOSFETs, and gel dosimeters. The measurements related to pre-treatment dose verification in IMRT of carcinoma prostate were carried out using ABS and Scanditronics-Wellhoffer RW3 IMRT phantoms for five different cases. Point dose data were acquired using ionization chamber and TLD discs while Gafchromic EBT and radiographic EDR2 films were used for generating 2-D dose distributions. Treatment planning system (TPS) calculated and measured doses in ABS plastic and RW3 IMRT phantom were in agreement within +/-2%. The dose values at a point in a given patient acquired using ABS and RW3 phantoms were found comparable within 1%. Fluence maps and dose distributions of these patients generated by TPS and measured in ABS IMRT phantom were also found comparable both numerically and spatially. This study indicates that ABS plastic IMRT phantom is a tissue equivalent phantom and dosimetrically it is similar to solid/plastic water IMRT phantoms. Though this material is demonstrated for IMRT dose verification but it can be used as a tissue equivalent phantom material for other dosimetry purposes in radiotherapy.

  4. The physical and degradation properties of starch-graft-acrylonitrile/carboxylated nitrile butadiene rubber latex films.

    PubMed

    Misman, M A; Azura, A R; Hamid, Z A A

    2015-09-01

    Starch-graft-acrylonitrile (ANS) is compounded with carboxylated nitrile butadiene rubber (XNBR) latex. The control XNBR and the ANS/XNBR latex films were prepared through a coagulant dipping process. The films were subjected to ageing and soil burial procedures. For the biodegradation experiment, the surface of the film was assessed after the 2nd, 4th and 8th week of soil burial. The ANS, XNBR, and ANS/XNBR colloidal stability were determined with a Malvern Zetasizer. For the dipped latex films, the mechanical, morphological and thermal properties were analyzed. The addition of ANS into the XNBR latex increased the stability of the colloidal dispersions, decreased the latex film tensile strength, but increased the elongation at break due to the bipolar interaction of the ANS and XNBR particles. The ANS/XNBR latex films aged faster than the control films while the morphological analysis showed the existence of a starch crystal region and the formation of microbial colonies on the surfaces of the films. Based on the TGA-DTA curves, a higher ΔT was observed for the ANS/XNBR latex films signifying high thermal energy needed for the film to thermally degrade. PMID:26005134

  5. Design and testing of digitally manufactured paraffin Acrylonitrile-butadiene-styrene hybrid rocket motors

    NASA Astrophysics Data System (ADS)

    McCulley, Jonathan M.

    This research investigates the application of additive manufacturing techniques for fabricating hybrid rocket fuel grains composed of porous Acrylonitrile-butadiene-styrene impregnated with paraffin wax. The digitally manufactured ABS substrate provides mechanical support for the paraffin fuel material and serves as an additional fuel component. The embedded paraffin provides an enhanced fuel regression rate while having no detrimental effect on the thermodynamic burn properties of the fuel grain. Multiple fuel grains with various ABS-to-Paraffin mass ratios were fabricated and burned with nitrous oxide. Analytical predictions for end-to-end motor performance and fuel regression are compared against static test results. Baseline fuel grain regression calculations use an enthalpy balance energy analysis with the material and thermodynamic properties based on the mean paraffin/ABS mass fractions within the fuel grain. In support of these analytical comparisons, a novel method for propagating the fuel port burn surface was developed. In this modeling approach the fuel cross section grid is modeled as an image with white pixels representing the fuel and black pixels representing empty or burned grid cells.

  6. Synthesis and evaluation of a series of benzothiophene acrylonitrile analogs as anticancer agents

    PubMed Central

    Penthala, Narsimha Reddy; Sonar, Vijayakumar, N.; Horn, Jamie; Leggas, Markos; Yadlapalli, Jai Shankar K. B.; Crooks, Peter A.

    2013-01-01

    A new library of small molecules with structural features resembling combretastatin analogs was synthesized and evaluated for anticancer activity against a panel of 60 human cancer cell lines. Three novel acrylonitrile analogs (5, 6 and 13) caused a significant reduction in cell growth in almost all the cell lines examined, with GI50 values generally in the range 10–100 nM. Based on the structural characteristics of similar drugs, we hypothesized that the cytotoxic activity was likely due to interaction with tubulin. Furthermore, these compounds appeared to overcome cell-associated P-glycoprotein (P-gp)-mediated resistance, since they were equipotent in inhibiting OVCAR8 and NCI/ADR-Res cell growth. Given that antitubulin drugs are among the most effective agents for the treatment of advanced prostate cancer we sought to validate the results from the 60 cell panel by studying the representative analog 6 utilizing prostate cancer cell lines, as well as exploring the molecular mechanism of the cytotoxic action of this analog. PMID:23956835

  7. Nanocomposites prepared from acrylonitrile butadiene rubber and organically modified montmorillonite with vinyl groups

    NASA Astrophysics Data System (ADS)

    Han, Mijeong; Kim, Hoonjung; Kim, Eunkyoung

    2006-01-01

    Nanocomposites were prepared from acrylonitrile-butadiene rubber (NBR), vinyl groups containing organically modified montmorillonite and additives, such as zinc oxide, stearic acid, and sulfur. The organically modified montmorillonites used in these nanocomposites were prepared by ion exchange reactions of N,N'-dimethylalkyl-(p-vinylbenzyl)-ammonium chlorides (DAVBAs, alkyl = octyl, dodecyl, and octadecyl) with sodium montmorillonite (Na+-MMT). NBR nanocomposites were obtained by controlling both the mixing and vulcanization conditions, by using a Brabender mixer and hot-press process. X-ray diffraction (XRD) analysis shows that, depending on the amount of montmorillonite that is added, both exfoliated and intercalated nanocomposite structures are formed. The NBR/DAVBA-MMT nanocomposites exhibit much higher mechanical properties (e.g., tensile strength, Young's modulus, 300% modulus, and hardness) as well as gas barrier properties as compared to NBR Na+-MMT or NBR composites generated from modified montmorillonites without vinyl groups. Consistent with the results of XRD, transmission electron microscopy (TEM) reveals that the intercalation and exfoliation structures of the nanocomposites coexist and that the DAVBA-MMT layers are well dispersed in NBR.

  8. Hg(II) adsorption using amidoximated porous acrylonitrile/itaconic copolymers prepared by suspended emulsion polymerization.

    PubMed

    Ji, Chunnuan; Qu, Rongjun; Chen, Hou; Liu, Xiguang; Sun, Changmei; Ma, Caixia

    2016-01-01

    Initially, porous acrylonitrile/itaconic acid copolymers (AN/IA) were prepared by suspended emulsion polymerization. Successively, the cyano groups in AN/IA copolymers were converted to amidoxime (AO) groups by the reaction with hydroxylamine hydrochloride. The structures of the AN/IA and amidoximated AN/IA (AO AN/IA) were characterized by infrared spectroscopy, scanning electron microscopy, and porous structural analysis. The adsorption properties of AO AN/IA for Hg(II) were investigated. The results show that AO AN/IA has mesopores and macropores, and surface area of 11.71 m(2) g(-1). It was found that AO AN/IA has higher affinity for Hg(II), with the maximum adsorption capacity of 84.25 mg g(-1). The AO AN/IA also can effectively remove Hg(II) from different binary metal ion mixture systems. Furthermore, the adsorption kinetics and thermodynamics were studied in detail. The adsorption equilibrium can quickly be achieved in 4 h determined by an adsorption kinetics study. The adsorption process is found to belong to the second-order model, and can be described by the Freundlich model. PMID:27054744

  9. Method for the separation of high impact polystyrene (HIPS) and acrylonitrile butadiene styrene (ABS) plastics

    DOEpatents

    Jody, Bassam J.; Arman, Bayram; Karvelas, Dimitrios E.; Pomykala, Jr., Joseph A.; Daniels, Edward J.

    1997-01-01

    An improved method is provided for separating acrylonitrile butadiene styrene (ABS) and high impact polystyrene (HIPS) plastics from each other. The ABS and HIPS plastics are shredded to provide a selected particle size. The shredded particles of the ABS and HIPS plastics are applied to a solution having a solution density in a predefined range between 1.055 gm/cm.sup.3 and 1.07 gm/cm.sup.3, a predefined surface tension in a range between 22 dynes/cm to 40 dynes/cm and a pH in the range of 1.77 and 2.05. In accordance with a feature of the invention, the novel method is provided for separating ABS and HIPS, two solid thermoplastics which have similar densities by selectively modifying the effective density of the HIPS using a binary solution with the appropriate properties, such as pH, density and surface tension, such as a solution of acetic acid and water or a quaternary solution having the appropriate density, surface tension, and pH.

  10. Phenomena affecting morphology of microporous poly(acrylonitrile) prepared via phase separation from solution

    SciTech Connect

    Legasse, R.R.; Weagley, R.J.; Leslie, P.K.; Schneider, D.A.

    1990-01-01

    This paper is concerned with controlling the morphology of microporous polymers prepared via thermal demixing of solutions. 2 wt % solutions of poly(acrylonitrile) in maleic anhydride, a poor solvent, are first cooled to produce separated polymer-rich and solvent-rich phases. Removing the solvent by freeze drying then produces a microporous material having a density of 33 mg/cm{sup 3}, a void fraction of 97%, and a pore size of about 10 {mu}m. We find that the morphology cannot be explained by existing models, which focus on phase diagrams and kinetics of phase transformations during cooling of the solution. In conflict with those models, we find that two radically different morphologies can be produced even when the polymer concentration and cooling path are held strictly constant. A hypothesis that polymer degradation causes the different morphologies is not supported by GPC, {sup 13}C NMR, and FTIR experiments. Instead, we offer evidence that the different microporous morphologies are caused by different polymer conformations in solutions having the same concentration and temperature. 11 refs., 3 figs.

  11. Design, synthesis, and anti-melanogenic effects of (E)-2-benzoyl-3-(substituted phenyl)acrylonitriles

    PubMed Central

    Yun, Hwi Young; Kim, Do Hyun; Son, Sujin; Ullah, Sultan; Kim, Seong Jin; Kim, Yeon-Jeong; Yoo, Jin-Wook; Jung, Yunjin; Chun, Pusoon; Moon, Hyung Ryong

    2015-01-01

    Background Tyrosinase is the most prominent target for inhibitors of hyperpigmentation because it plays a critical role in melaninogenesis. Although many tyrosinase inhibitors have been identified, from both natural and synthetic sources, there remains a considerable demand for novel tyrosinase inhibitors that are safer and more effective. Methods (E)-2-Benzoyl-3-(substituted phenyl)acrylonitriles (BPA analogs) with a linear β-phenyl-α,β-unsaturated carbonyl scaffold were designed and synthesized as potential tyrosinase inhibitors. We evaluated their effects on cellular tyrosinase activity and melanin biosynthesis in murine B16F10 melanoma cells and their ability to inhibit mushroom tyrosinase activity. Results BPA analogs exhibited inhibitory activity against mushroom tyrosinase. In particular, BPA13 significantly suppressed melanin biosynthesis and inhibited cellular tyrosinase activity in B16F10 cells in a dose-dependent manner. A docking study revealed that BPA13 had higher binding affinity for tyrosinase than kojic acid. Conclusion BPA13, which possesses a linear β-phenyl-α,β-unsaturated carbonyl scaffold, is a potential candidate skin-whitening agent and treatment for diseases associated with hyperpigmentation. PMID:26347064

  12. An investigation on chloroprene-compatibilized acrylonitrile butadiene rubber/high density polyethylene blends

    PubMed Central

    Ahmed, Khalil

    2014-01-01

    Blends of acrylonitrile butadiene rubber/high density polyethylene (NBR/HDPE) compatibilized by Chloroprene rubber (CR) were prepared. A fixed quantity of industrial waste such as marble waste (MW, 40 phr) was also included. The effect of the blend ratio and CR on cure characteristics, mechanical and swelling properties of MW-filled NBR/HDPE blends was investigated. The results showed that the MW-filled NBR/HDPE blends revealed an increase in tensile strength, tear, modulus, hardness and cross-link density for increasing weight ratio of HDPE. The minimum torque (ML) and maximum torque (MH) of blends increased with increasing weight ratio of HDPE while scorch time (ts2) cure time (tc90), compression set and abrasion loss of blends decreased with increasing weight ratio of HDPE. The blends also showed a continuous reduction in elongation at break as well as swelling coefficient with increasing HDPE amount in blends. MW filled blends based on CR provided the most encouraging balance values of overall properties. PMID:26644917

  13. Cobalt-Mediated Radical Polymerization of Vinyl Acetate and Acrylonitrile in Supercritical Carbon Dioxide.

    PubMed

    Kermagoret, Anthony; Chau, Ngoc Do Quyen; Grignard, Bruno; Cordella, Daniela; Debuigne, Antoine; Jérôme, Christine; Detrembleur, Christophe

    2016-03-01

    Cobalt-mediated radical polymerization (CMRP) of vinyl acetate (VAc) is successfully achieved in supercritical carbon dioxide (scCO2). CMRP of VAc is conducted using an alkyl-cobalt(III) adduct that is soluble in scCO2. Kinetics studies coupled to visual observations of the polymerization medium highlight that the melt viscosity and PVAc molar mass (Mn) are key parameters that affect the CMRP in scCO2. It is noticed that CMRP is controlled for Mn up to 10 000 g mol(-1), but loss of control is progressively observed for higher molar masses when PVAc precipitates in the polymerization medium. Low molar mass PVAc macroinitiator, prepared by CMRP in scCO2, is then successfully used to initiate the acrylonitrile polymerization. PVAc-b-PAN block copolymer is collected as a free flowing powder at the end of the process although the dispersity of the copolymer increases with the reaction time. Although optimization is required to decrease the dispersity of the polymer formed, this CMRP process opens new perspectives for macromolecular engineering in scCO2 without the utilization of fluorinated comonomers or organic solvents.

  14. Effects of acrylonitrile on lymphocyte lipid rafts and RAS/RAF/MAPK/ERK signaling pathways.

    PubMed

    Li, X J; Li, B; Huang, J S; Shi, J M; Wang, P; Fan, W; Zhou, Y L

    2014-09-26

    Acrylonitrile (ACN) is a widely used chemical in the production of plastics, resins, nitriles, acrylic fibers, and synthetic rubber. Previous epidemiological investigations and animal studies have confirmed that ACN affects the lymphocytes and spleen. However, the immune toxicity mechanism is unknown. Lipid rafts are cell membrane structures that are rich in cholesterol and involved in cell signal transduction. The B cell lymophoma-10 (Bcl10) protein is a joint protein that is important in lymphocyte development and signal pathways. This study was conducted to examine the in vitro effects of ACN. We separated lipid rafts, and analyzed Bcl10 protein and caveolin. Western blotting was used to detect mitogen-activated protein kinase (MAPK) and phosphorylated MAPK levels. The results indicated that with increasing ACN concentration, the total amount of Bcl10 remained stable, but was concentrated mainly in part 4 to part 11 in electrophoretic band district which is high density in gradient centrifugation. Caveolin-1 was evaluated as a lipid raft marker protein; caveolin-1 content and position were relatively unchanged. Western blotting showed that in a certain range, MAPK protein was secreted at a higher level. At some ACN exposure levels, MAPK protein secretion was significantly decreased compared to the control group (P < 0.05). These results indicate that ACN can cause immune toxicity by damaging lipid raft structures, causing Bcl10 protein and lipid raft separation and restraining Ras-Raf-MAPK-extracellular signal-regulated kinase signaling pathways.

  15. High-Energy-Density Poly(styrene-co-acrylonitrile) Thin Films

    NASA Astrophysics Data System (ADS)

    Wen, Fei; Xu, Zhuo; Xia, Weimin; Ye, Hongjun; Wei, Xiaoyong; Zhang, Zhicheng

    2013-12-01

    The dielectric response of poly(styrene-co-acrylonitrile) (PSAN) thin films fabricated by a solution casting process was investigated in this work. Linear dielectric behavior was obtained in PSAN films under an electric field at frequencies from 100 Hz to 1 MHz and temperature of -50°C to 100°C. The polymer films exhibited an intermediate dielectric permittivity of 4 and low dielectric loss (tan δ) of 0.027. Under 400 MV/m, the energy density of the PSAN films was 6.8 J/cm3, which is three times higher than that of biaxially oriented polypropylene (BOPP) (about 1.6 J/cm3). However, their charge-discharge efficiency (about 90%) was rather close to that of BOPP. The calculated effective dielectric permittivity of the PSAN films under high electric field was as high as 9, which may be attributed to the improved displacement of the cyanide groups (-CN) polarized at high electric fields. These high-performance features make PSAN attractive for high-energy-density capacitor applications.

  16. Synthesis and evaluation of a series of benzothiophene acrylonitrile analogs as anticancer agents.

    PubMed

    Penthala, Narsimha Reddy; Sonar, Vijayakumar N; Horn, Jamie; Leggas, Markos; Yadlapalli, Jai Shankar K B; Crooks, Peter A

    2013-07-01

    A new library of small molecules with structural features resembling combretastatin analogs was synthesized and evaluated for anticancer activity against a panel of 60 human cancer cell lines. Three novel acrylonitrile analogs (5, 6 and 13) caused a significant reduction in cell growth in almost all the cell lines examined, with GI50 values generally in the range 10-100 nM. Based on the structural characteristics of similar drugs, we hypothesized that the cytotoxic activity was likely due to interaction with tubulin. Furthermore, these compounds appeared to overcome cell-associated P-glycoprotein (P-gp)-mediated resistance, since they were equipotent in inhibiting OVCAR8 and NCI/ADR-Res cell growth. Given that antitubulin drugs are among the most effective agents for the treatment of advanced prostate cancer we sought to validate the results from the 60 cell panel by studying the representative analog 6 utilizing prostate cancer cell lines, as well as exploring the molecular mechanism of the cytotoxic action of this analog.

  17. Effects of acrylonitrile on lymphocyte lipid rafts and RAS/RAF/MAPK/ERK signaling pathways.

    PubMed

    Li, X J; Li, B; Huang, J S; Shi, J M; Wang, P; Fan, W; Zhou, Y L

    2014-01-01

    Acrylonitrile (ACN) is a widely used chemical in the production of plastics, resins, nitriles, acrylic fibers, and synthetic rubber. Previous epidemiological investigations and animal studies have confirmed that ACN affects the lymphocytes and spleen. However, the immune toxicity mechanism is unknown. Lipid rafts are cell membrane structures that are rich in cholesterol and involved in cell signal transduction. The B cell lymophoma-10 (Bcl10) protein is a joint protein that is important in lymphocyte development and signal pathways. This study was conducted to examine the in vitro effects of ACN. We separated lipid rafts, and analyzed Bcl10 protein and caveolin. Western blotting was used to detect mitogen-activated protein kinase (MAPK) and phosphorylated MAPK levels. The results indicated that with increasing ACN concentration, the total amount of Bcl10 remained stable, but was concentrated mainly in part 4 to part 11 in electrophoretic band district which is high density in gradient centrifugation. Caveolin-1 was evaluated as a lipid raft marker protein; caveolin-1 content and position were relatively unchanged. Western blotting showed that in a certain range, MAPK protein was secreted at a higher level. At some ACN exposure levels, MAPK protein secretion was significantly decreased compared to the control group (P < 0.05). These results indicate that ACN can cause immune toxicity by damaging lipid raft structures, causing Bcl10 protein and lipid raft separation and restraining Ras-Raf-MAPK-extracellular signal-regulated kinase signaling pathways. PMID:25299088

  18. Carbon nanotube buckypaper reinforced acrylonitrile-butadiene-styrene composites for electronic applications.

    PubMed

    Díez-Pascual, Ana M; Gascón, David

    2013-11-27

    Novel acrylonitrile-butadiene-styrene (ABS) nanocomposites reinforced with pristine or functionalized single- or multiwalled carbon nanotube buckypaper (BP) sheets were manufactured via hot-compression and vacuum infiltration. Their morphology, thermal, mechanical, and electrical properties were comparatively investigated. Scanning electron microscopy and thermogravimetric analysis showed that the infiltration process leads to better BP impregnation than the hot-press technique. BPs made from functionalized or short nanotubes form compact networks that hamper the penetration of the matrix chains, whereas those composed of pristine tubes possess large pores that facilitate the polymer flow, resulting in composites with low degree of porosity and improved mechanical performance. Enhanced thermal and electrical properties are found for samples incorporating functionalized BPs since dense networks lead to more conductive pathways, and a stronger barrier effect to the diffusion of degradation products, thus better thermal stability. According to dynamic mechanical analysis these composites exhibit the highest glass transition temperatures, suggesting enhanced filler-matrix interactions as corroborated by the Raman spectra. The results presented herein demonstrate that the composite performance can be tailored by controlling the BP architecture and offer useful insights into the structure-property relationships of these materials to be used in electronic applications, particularly for EMI shielding and packaging of integrated circuits. PMID:24171494

  19. Determination of acrylonitrile in foods by headspace gas-liquid chromatography with nitrogen-phosphorus detection.

    PubMed

    Page, B D; Charbonneau, C F

    1983-09-01

    A general procedure is described for the determination of acrylonitrile (AN) in foods such as margarine, honey butter, cold-pack cheese, and peanut butter, which are likely to be packaged in AN-based plastic. The entire sample is blended with water and salt at less than 5 degrees C, aliquots are sealed in crimp-top vials, and the vials are equilibrated in a boiling water bath. The headspace is sampled by using a heated syringe, and AN is determined by gas chromatography with a nitrogen-phosphorus selective detector. The inclusion of propionitrile as an internal standard allows quantitation of AN with detection at 4,4, and 10 ppb for margarine, honey butter, and cold-pack cheese, respectively. A peak corresponding to about 5 ppb apparent AN in all non-AN-packaged peanut butter samples examined limits detection in peanut butter to about 15 ppb. The coefficients of variation at 20 ppb for margarine, honey butter, cold-pack cheese, and peanut butter were 7.5, 8.3, 7.3, and 10.2%, respectively.

  20. Modification of fiber properties through grafting of acrylonitrile to rayon by chemical and radiation methods.

    PubMed

    Kaur, Inderjeet; Sharma, Neelam; Kumari, Vandna

    2013-11-01

    Fibrous properties of rayon has been modified through synthesis of graft copolymers of rayon with acrylonitrile (AN) by chemical method using ceric ammonium nitrate (CAN/HNO3) as a redox initiator and gamma radiation mutual method. Percentage of grafting (Pg) was determined as a function of initiator concentration, monomer concentration, irradiation dose, temperature, time of reaction and the amount of water. Maximum percentage of grafting (160.01%) using CAN/HNO3 was obtained at [CAN] = 22.80 × 10(-3) mol/L, [HNO3] = 112.68 × 10(-2) mol/L and [AN] = 114.49 × 10(-2) mol/L in 20 mL of water at 45 °C within 120 min while in case of gamma radiation method, maximum Pg (90.24%) was obtained at an optimum concentration of AN of 76.32 × 10(-2) mol/L using 10 mL of water at room temperature with total dose exposure of 3.456 kGy/h. The grafted fiber was characterized by FTIR, SEM, TGA and XRD studies. Swelling behavior of grafted rayon in different solvents such as water, methanol, ethanol, DMF and acetone was studied and compared with the unmodified rayon. Dyeing behavior of the grafted fiber was also investigated.

  1. Optical properties of polycarbonate/styrene-co-acrylonitrile blends: effects of molecular weight of the matrix.

    PubMed

    Yi, Ping; Xiong, Ying; Guo, Shaoyun

    2015-12-01

    In this paper, the effects of the molecular weight of a polycarbonate (PC) matrix on the phase morphology and optical properties of a PC/styrene-co-acrylonitrile (SAN) blend were investigated. A scanning electron microscope is used to analyze the phase morphology of the blends, and Mie scattering theory is used to analyze the changing laws of the optical properties of PC/SAN blends with the increasing of PC molecular weight. Results show that the average particle diameter is not strongly changed with different PC molecular weight because the values of the viscosity ratios are very close to each other. But it is obvious that the number of large particles gradually reduced while small particles (especially d<2  μm) significantly increased with the increasing of PC molecular weight. And the increase in small particles will result in an increase in backward scattering so the transmittance of PC/SAN blends decreases with the increase of PC molecular weight. However, the balance of the scattering coefficients and the number concentration of particles eventually lead to the haze of the blends being very close, despite having different PC molecular weights. Meanwhile, the photographs of scattering patterns indicate that the PC/SAN blends whose component weight ratios are fixed at 70:30 have excellent antiglare properties, despite the changes in molecular weight of the PC matrix.

  2. Lasing properties of sodium-gadolinium tungstate NaGd(WO{sub 4}){sub 2} crystals doped with Tm{sup 3+} ions

    SciTech Connect

    Zharikov, Evgeny V; Lis, Denis A; Popov, A V; Subbotin, Kirill A; Ushakov, S N; Shestakov, A V; Razdobreev, I M

    2006-06-30

    Lasing is obtained in Tm{sup 3+}-doped sodium-gadolinium tungstate NaGd(WO{sub 4}){sub 2} crystals longitudinally pumped by pulses from a laser diode bar. The slope lasing efficiency is 16%. Lasing was observed at wavelengths of 1957, 1944, 1936, and 1901 nm for the transmission coefficients of the output mirror T{sub out} = 0.3%, 1.4%, 3.3%, and 8.5%, respectively. (lasers)

  3. Local pharmacological effects of tungstate on the color-pattern determination of butterfly wings: a possible relationship between the eyespot and parafocal element.

    PubMed

    Dhungel, Bidur; Otaki, Joji M

    2009-11-01

    Butterfly wing color patterns can be changed by the application of a temperature shock or pharmacological agents such as tungstate, producing a distinctive type of elemental modification called the TS (temperature shock) type. Heterochronic uncoupling between the signaling and reception steps during the color-pattern determination process has been proposed as a mechanism for TS-type changes. As an extension of this hypothesis, both the parafocal element (PFE) and the eyespot in the same wing compartment are considered to be determined by morphogenic signal(s) emitted from the same eyespot focus. However, these models need to be examined with additional experimental data. Furthermore, there is controversy as to whether the action of tungstate on wing color patterns is direct or Indirect. Using a species of nymphalid butterfly (Junonia orithya), we have devised a simple method for the local application of pharmacological agents directly on developing wings of pupae. Local tungstate application resulted in reduced eyespots and circular dislocated PFEs in the eyespot-less compartments only on the treated wing, demonstrating that tungstate directly induces color-pattern changes on wings. We further examined the eyespot-PFE relationship in normal and cold-shocked Individuals, showing that an eyespot can be superimposed on a PFE and vice versa, probably depending on the timing of their fate determination. Taken together, we propose a two-morphogen model for the normal color-pattern determination, in which the morphogenic signals for the eyespot and PFE are different from each other despite their Identical origin. This two-morphogen model is compatible with the heterochronic uncoupling model for TS-type changes. PMID:19877835

  4. Local pharmacological effects of tungstate on the color-pattern determination of butterfly wings: a possible relationship between the eyespot and parafocal element.

    PubMed

    Dhungel, Bidur; Otaki, Joji M

    2009-11-01

    Butterfly wing color patterns can be changed by the application of a temperature shock or pharmacological agents such as tungstate, producing a distinctive type of elemental modification called the TS (temperature shock) type. Heterochronic uncoupling between the signaling and reception steps during the color-pattern determination process has been proposed as a mechanism for TS-type changes. As an extension of this hypothesis, both the parafocal element (PFE) and the eyespot in the same wing compartment are considered to be determined by morphogenic signal(s) emitted from the same eyespot focus. However, these models need to be examined with additional experimental data. Furthermore, there is controversy as to whether the action of tungstate on wing color patterns is direct or Indirect. Using a species of nymphalid butterfly (Junonia orithya), we have devised a simple method for the local application of pharmacological agents directly on developing wings of pupae. Local tungstate application resulted in reduced eyespots and circular dislocated PFEs in the eyespot-less compartments only on the treated wing, demonstrating that tungstate directly induces color-pattern changes on wings. We further examined the eyespot-PFE relationship in normal and cold-shocked Individuals, showing that an eyespot can be superimposed on a PFE and vice versa, probably depending on the timing of their fate determination. Taken together, we propose a two-morphogen model for the normal color-pattern determination, in which the morphogenic signals for the eyespot and PFE are different from each other despite their Identical origin. This two-morphogen model is compatible with the heterochronic uncoupling model for TS-type changes.

  5. Analysis of acrylonitrile, 1,3-butadiene, and related compounds in acrylonitrile-butadiene-styrene copolymers for kitchen utensils and children's toys by headspace gas chromatography/mass spectrometry.

    PubMed

    Ohno, Hiroyuki; Kawamura, Yoko

    2010-01-01

    A headspace gas chromatography/mass spectrometry method was developed for the simultaneous determination of the residual levels of acrylonitrile (AN), 1,3-butadiene (1,3-BD), and their related compounds containing propionitrile (PN) and 4-vinyl-1-cyclohexene (4-VC) in acrylonitrile-butadiene-styrene (ABS) copolymers for kitchen utensils and children's toys. A sample was cut into small pieces, then N,N-dimethylacetamide and an internal standard were added in a sealed headspace vial. The vial was incubated for 1 h at 90 degrees C and the headspace gas was analyzed by gas chromatography/mass spectrometry. The recovery rates of the analytes were 93.3-101.8% and the coefficients of variation were 0.3-6.5%. In ABS copolymers, the levels were 0.3-50.4 microg/g for AN, ND-4.5 microg/g for PN, 0.06-1.58 microg/g for 1,3-BD, and 1.1-295 microg/g for 4-VC. The highest level was found for 4-VC, which is a dimer of 1,3-BD, and the next highest was for AN, which is one of the monomers of the ABS copolymer. Furthermore, the method was also applied to acrylonitrile-styrene (AS) copolymers and polystyrenes (PS) for kitchen utensils, and nitrile-butadiene rubber (NBR) gloves. In AS copolymers, AN and PN were detected at 16.8-54.5 and 0.8-6.9 microg/g, respectively. On the other hand, the levels in PS and NBR samples were all low. PMID:21313827

  6. Analysis of acrylonitrile, 1,3-butadiene, and related compounds in acrylonitrile-butadiene-styrene copolymers for kitchen utensils and children's toys by headspace gas chromatography/mass spectrometry.

    PubMed

    Ohno, Hiroyuki; Kawamura, Yoko

    2010-01-01

    A headspace gas chromatography/mass spectrometry method was developed for the simultaneous determination of the residual levels of acrylonitrile (AN), 1,3-butadiene (1,3-BD), and their related compounds containing propionitrile (PN) and 4-vinyl-1-cyclohexene (4-VC) in acrylonitrile-butadiene-styrene (ABS) copolymers for kitchen utensils and children's toys. A sample was cut into small pieces, then N,N-dimethylacetamide and an internal standard were added in a sealed headspace vial. The vial was incubated for 1 h at 90 degrees C and the headspace gas was analyzed by gas chromatography/mass spectrometry. The recovery rates of the analytes were 93.3-101.8% and the coefficients of variation were 0.3-6.5%. In ABS copolymers, the levels were 0.3-50.4 microg/g for AN, ND-4.5 microg/g for PN, 0.06-1.58 microg/g for 1,3-BD, and 1.1-295 microg/g for 4-VC. The highest level was found for 4-VC, which is a dimer of 1,3-BD, and the next highest was for AN, which is one of the monomers of the ABS copolymer. Furthermore, the method was also applied to acrylonitrile-styrene (AS) copolymers and polystyrenes (PS) for kitchen utensils, and nitrile-butadiene rubber (NBR) gloves. In AS copolymers, AN and PN were detected at 16.8-54.5 and 0.8-6.9 microg/g, respectively. On the other hand, the levels in PS and NBR samples were all low.

  7. Uncertainty and variability in the exposure reconstruction of chemical incidents--the case of acrylonitrile.

    PubMed

    Huizer, Daan; Ragas, Ad M J; Oldenkamp, Rik; van Rooij, Joost G M; Huijbregts, Mark A J

    2014-12-15

    The application of human physiologically based pharmacokinetic (PBPK) modeling combined with measured biomonitoring data, has a great potential to backtrack external exposure to chemicals during chemical incidents. So far, an important shortcoming of 'reversed dosimetry' is that uncertainty and variability in the model predictions are often neglected. The aim of this paper is to characterize the variation in predicted environmental air concentrations by means of reversed dosimetry as a result of uncertainty in chemical-specific input data and variability in physiological parameters. Human biomonitoring data (N-2-cyanoethylvaline in blood) from a chemical incident with acrylonitrile (ACN) combined with the BioNormtox PBPK model are used as a case to reconstruct the air concentration and uncertainty thereof at the time of the incident. The influence of uncertainty in chemical-specific properties and exposure duration, and interindividual variability in physiological parameters on the reconstructed air exposure concentrations were quantified via nested Monte Carlo simulation. The range in the reconstructed air concentrations of ACN during the incident was within a factor of 3. Uncertainty in the exact exposure duration directly after the chemical accident was found to have a dominant influence on the model outcomes. It was also shown that uncertainty can be further reduced by collecting human biomonitoring data as soon as possible after the incident. Finally, the collection of specific information about individual physiological parameters from the victims, such as body weight, may further reduce the variation by 5 to 20% in our case study. Future research should include the comparison of reversed dosimetry model outcomes with measured air and biological concentrations to further increase the confidence in the model approach and its implementation in practice.

  8. Modification of fiber properties through grafting of acrylonitrile to rayon by chemical and radiation methods.

    PubMed

    Kaur, Inderjeet; Sharma, Neelam; Kumari, Vandna

    2013-11-01

    Fibrous properties of rayon has been modified through synthesis of graft copolymers of rayon with acrylonitrile (AN) by chemical method using ceric ammonium nitrate (CAN/HNO3) as a redox initiator and gamma radiation mutual method. Percentage of grafting (Pg) was determined as a function of initiator concentration, monomer concentration, irradiation dose, temperature, time of reaction and the amount of water. Maximum percentage of grafting (160.01%) using CAN/HNO3 was obtained at [CAN] = 22.80 × 10(-3) mol/L, [HNO3] = 112.68 × 10(-2) mol/L and [AN] = 114.49 × 10(-2) mol/L in 20 mL of water at 45 °C within 120 min while in case of gamma radiation method, maximum Pg (90.24%) was obtained at an optimum concentration of AN of 76.32 × 10(-2) mol/L using 10 mL of water at room temperature with total dose exposure of 3.456 kGy/h. The grafted fiber was characterized by FTIR, SEM, TGA and XRD studies. Swelling behavior of grafted rayon in different solvents such as water, methanol, ethanol, DMF and acetone was studied and compared with the unmodified rayon. Dyeing behavior of the grafted fiber was also investigated. PMID:25685464

  9. Modification of fiber properties through grafting of acrylonitrile to rayon by chemical and radiation methods

    PubMed Central

    Kaur, Inderjeet; Sharma, Neelam; Kumari, Vandna

    2013-01-01

    Fibrous properties of rayon has been modified through synthesis of graft copolymers of rayon with acrylonitrile (AN) by chemical method using ceric ammonium nitrate (CAN/HNO3) as a redox initiator and gamma radiation mutual method. Percentage of grafting (Pg) was determined as a function of initiator concentration, monomer concentration, irradiation dose, temperature, time of reaction and the amount of water. Maximum percentage of grafting (160.01%) using CAN/HNO3 was obtained at [CAN] = 22.80 × 10−3 mol/L, [HNO3] = 112.68 × 10−2 mol/L and [AN] = 114.49 × 10−2 mol/L in 20 mL of water at 45 °C within 120 min while in case of gamma radiation method, maximum Pg (90.24%) was obtained at an optimum concentration of AN of 76.32 × 10−2 mol/L using 10 mL of water at room temperature with total dose exposure of 3.456 kGy/h. The grafted fiber was characterized by FTIR, SEM, TGA and XRD studies. Swelling behavior of grafted rayon in different solvents such as water, methanol, ethanol, DMF and acetone was studied and compared with the unmodified rayon. Dyeing behavior of the grafted fiber was also investigated. PMID:25685464

  10. Design of poly(acrylonitrile)-based gel electrolytes for high-performance lithium ion batteries.

    PubMed

    Wang, Shih-Hong; Kuo, Ping-Lin; Hsieh, Chien-Te; Teng, Hsisheng

    2014-11-12

    The use of polyacrylonitrile (PAN) as a host for gel polymer electrolytes (GPEs) commonly produces a strong dipole-dipole interaction with the polymer. This study presents a strategy for the application of PAN in GPEs for the production of high performance lithium ion batteries. The resulting gel electrolyte GPE-AVM comprises a poly(acrylonitrile-co-vinyl acetate) copolymer blending poly(methyl methacrylate) as a host, which is swelled using a liquid electrolyte (LE) of 1 M LiPF6 in carbonate solvent. Vinyl acetate and methacrylate groups segregate the PAN chains in the GPE, which produces high ionic conductivity (3.5 × 10 (-3) S cm(-1) at 30 °C) and a wide electrochemical voltage range (>6.5 V) as well as an excellent Li(+) transference number of 0.6. This study includes GPE-AVM in a full-cell battery comprising a LiFePO4 cathode and graphite anode to promote ion motion, which reduced resistance in the battery by 39% and increased the specific power by 110%, relative to the performance of batteries based on LE. The proposed GPE-based battery has a capacity of 140 mAh g(-1) at a discharge rate of 0.1 C and is able to deliver 67 mAh g(-1) of electricity at 17 C. The proposed GPE-AVM provides a robust interface with the electrodes in full-cell batteries, resulting in 93% capacity retention after 100 charge-discharge cycles at 17 C and 63% retention after 1000 cycles.

  11. Modeling contaminant transport and remediation at an acrylonitrile spill site in Turkey.

    PubMed

    Sengör, S Sevinç; Unlü, Kahraman

    2013-07-01

    The August 1999 earthquake in Turkey damaged three acrylonitrile (AN) storage tanks at a plant producing synthetic fiber by polymerization. A numerical modeling study was carried out to analyze the groundwater flow and contaminant (AN) transport at the spill site. This study presents the application of a numerical groundwater model to determine the hydrogeological parameters of the site, where such data were not available during the field surveys prior to the simulation studies. The two- and three-dimensional transient flow and transport models were first calibrated using the first 266days of observed head and concentration data and then verified using the remaining 540-day observed data set. Off-site migration of the contaminant plume was kept under control within the site boundaries owing to the favorable geology of the site, the characteristics of the local groundwater flow regime and the pumping operations. As expected, the applied pump-and-treat system was effective at high-permeability zones, but not fully effective at low-permeability zones. The results of long-term simulations for unconfined aquifer showed that the size of the plume in the high permeability zone shrank significantly due to the dilution by natural recharge. However, in the low permeability zone, it was not significantly affected. The study showed that accurate and sufficient data regarding the source characteristics, concentration and groundwater level measurements, groundwater pumping rates and their durations at each of the extraction points involved in the pump-and-treat system along with the hydrogeological site characterization are the key parameters for successful flow and transport model calibrations.

  12. Mechanistic diversity of the van Leusen reaction applied to 6-ketomorphinans and synthetic potential of the resulting acrylonitrile substructures.

    PubMed

    Schütz, Johannes; Windisch, Petra; Kristeva, Elka; Wurst, Klaus; Ongania, Karl-Hans; Horvath, Ulrike E I; Schottenberger, Herwig; Laus, Gerhard; Schmidhammer, Helmut

    2005-06-24

    Tosylmethyl isocyanide was used to convert 7,8-didehydro-6-ketomorphinans to 6,7-didehydromorphinan-6-carbonitriles with retainment of the 4,5-epoxy ring. However, ring opening occurred in the presence of NaH giving 5,6,7,8-tetradehydromorphinan-6-carbonitriles. Addition of nucleophiles such as Li diisopropylamide or Grignard reagents to the acrylonitrile substructure yielded ring-opened 5,6-didehydro products. Seven products were characterized by X-ray crystal structure analysis and revealed insight into the mechanistic diversity of the van Leusen reaction.

  13. Pre-irradiation induced emulsion co-graft polymerization of acrylonitrile and acrylic acid onto a polyethylene nonwoven fabric

    NASA Astrophysics Data System (ADS)

    Liu, Hanzhou; Yu, Ming; Ma, Hongjuan; Wang, Ziqiang; Li, Linfan; Li, Jingye

    2014-01-01

    A pre-irradiation induced emulsion co-graft polymerization method was used to introduce acrylonitrile and acrylic acid onto a PE nonwoven fabric. The use of acrylic acid is meant to improve the hydrophilicity of the modified fabric. The kinetics of co-graft polymerization were studied. The existence of polyacrylonitrile (PAN) and poly(acrylic acid) (PAAc) graft chains was proven by Fourier transform infrared spectroscopy (FTIR) analysis. The existence of the nitrile groups in the graft chains indicates that they are ready for further amidoximation and adsorption of heavy metal ions.

  14. A correlation study applied to biomarkers of internal and effective dose for acrylonitrile and 4-aminobiphenyl in smokers

    PubMed Central

    Scherer, Gerhard; Newland, Kirk; Papadopoulou, Ermioni

    2014-01-01

    The urinary metabolites 2-cyanoethylmercapturic acid and 4-aminobiphenyl have been correlated with tobacco smoke exposure. Similarly, 2-cyanoethylvaline and 4-aminobiphenyl haemoglobin adducts have been used as biomarkers of effective dose for the exposure to acrylonitrile and 4-aminobiphenyl, respectively. Each pair of biomarkers is derived from the same parent chemical; however, the correlation between the urinary and the haemoglobin biomarkers has not been investigated. Using clinical study samples, we report a weak correlation between urinary and haemoglobin biomarkers due to different accumulation and elimination rates. Time course analysis showed that a reduction in exposure was paralleled by a delayed reduction in haemoglobin adducts. PMID:24754403

  15. Lasing properties of selectively pumped Raman-active Nd{sup 3+}-doped molybdate and tungstate crystals

    SciTech Connect

    Basiev, Tasoltan T; Doroshenko, Maxim E; Ivleva, Lyudmila I; Osiko, Vyacheslav V; Kosmyna, M B; Komar', V K; Sulc, J; Jelinkova, H

    2006-08-31

    The lasing efficiency of Nd{sup 3+} ions is studied in laser materials capable of self-Raman frequency conversion. The lasing properties of tungstate and molybdate crystals with the scheelite structure (SrWO{sub 4}, BaWO{sub 4}, PbWO{sub 4}, SrMoO{sub 4}, PbMoO{sub 4}) activated with neodymium ions are investigated upon longitudinal pumping by a 750-nm alexandrite laser or a 800-nm diode laser. The slope lasing efficiency obtained for a Nd{sup 3+}:PbMoO{sub 4} laser emitting at 1054 nm is 54.3% for the total lasing efficiency of 46%, which is the best result for all the crystals with the scheelite structure studied so far. The simultaneous Q-switched lasing and self-Raman frequency conversion were demonstrated in neodymium-doped SrWO{sub 4}, PbWO{sub 4}, and BaWO{sub 4} crystals. (papers devoted to the 90th anniversary of a.m.prokhorov)

  16. Effects of Molybdate, Tungstate, and Selenium Compounds on Formate Dehydrogenase and Other Enzyme Systems in Escherichia coli1

    PubMed Central

    Enoch, Harry G.; Lester, Robert L.

    1972-01-01

    The role of selenium and molybdenum in the metabolism of Escherichia coli was explored by growing cells in a simple salts medium and examining the metabolic consequences of altering the concentration of molybdenum and selenium compounds in the medium. The addition of tungstate increased the molybdate deficiency of this medium, as reflected by lowered levels of enzyme systems previously recognized to require compounds of molybdenum and selenium for their formation [formate-dependent oxygen reduction, formate dehydrogenase (FDH) (EC 1.2.2.1), and nitrate reductase (EC 1.9.6.1)]. The requirement for selenium and molybdenum appears to be unique to the enzymes of formate and nitrate metabolism since molybdate- and selenite-deficient medium had no effect on the level of several dehydrogenase and oxidase systems, for which the electron donors were reduced nicotinamide adenine dinucleotide, succinate, d- or l-lactate, and glycerol. In addition, no effect was observed on the growth rate or cell yield with any carbon source tested (glucose, glycerol, dl-lactate, acetate, succinate, and l-malate) when the medium was deficient in molybdenum and selenium. dl-Selenocystine was about as effective as selenite in stimulating the formation of formate dehydrogenase, whereas dl-selenomethionine was only 1% as effective. In aerobic cells, an amount of FDH was formed such that 3,200 or 3,800 moles of formate were oxidized per min per mole of added selenium (added as dl-selenocystine or selenite, respectively). PMID:4555402

  17. Zirconium(IV) tungstate nanoparticles prepared through chemical co-precipitation method and its function as solid acid catalyst

    NASA Astrophysics Data System (ADS)

    Sadanandan, Manoj; Bhaskaran, Beena

    2014-08-01

    In this paper, we report the synthesis of zirconium(IV) tungstate nanoparticles, a new and efficient catalyst for the oxidation of benzyl alcohol and esterification of acetic acid with various alcohols. The nanoparticle catalyst was prepared using the room temperature chemical co-precipitation method. The catalyst was characterized with thermogravimetric and differential thermal analysis, elemental analysis, X-ray diffraction analysis (XRD), fourier transform infrared spectroscopy (FT-IR), high-resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM) and the Brunauer-Emmett-Teller (BET) surface area. The crystallite size was found to be ~20 nm as revealed by XRD, HRTEM and AFM. The Na+ exchange capacity was found to be 2.76 meq g-1 and the surface area of the compound measured using BET method was found to be 250-265 m2 g-1. The high value of ion exchange capacity indicates the presence of surface hydroxyl groups. The prepared nanoparticles have proven to be excellent catalysts for both oxidation and ester synthesis under mild reaction conditions. The mechanism of the catalytic reaction was studied as well.

  18. Spectroscopy and structural characteristics of Eu3+-activated perovskite tungstate Ba2La2ZnW2O12

    NASA Astrophysics Data System (ADS)

    Yang, Li; Huang, Yanlin; Cheng, Han; Seo, Hyo Jin

    2015-11-01

    Eu3+-doped tungstate Ba2La2ZnW2O12 was prepared by the high-temperature solid-state reaction method. The x-ray powder diffraction (XRD) patterns indicate that the matrix has a perovskite structure. The samples were characterized by the scanning electron microscope (SEM), by optical diffuse reflection, photoluminescence (PL) spectra and by their decay curves. Eu3+-activated Ba2La2ZnW2O12 shows red luminescence under the excitation of near-ultraviolet and blue light. Laser site-selective excitation and emission spectroscopy technology was applied to investigate the spectroscopic and microstructural properties. The excitation spectra were tested by monitoring the emission from 5D0  →  7F0-4 transitions. Accordingly the emission spectra and decay curves (lifetime) were measured by the excitation in the 5D0  →  7F0 wavelength region using a pulsed, tunable, and narrow-band dye laser. We have detected two Eu3+ sites in Ba2La2ZnW2O12 with the temperature region ranging from 10 K to below 300 K. On the spectra data of the site-selective emission and decay, the Stark energy levels of Eu3+ at two different sites were determined. The lifetimes of Eu3+ ions at the two sites were compared. The energy transfer and crystallographic assignments for the Eu3+ sites were discussed.

  19. Fabrication of Acrylonitrile-Butadiene-Styrene Nanostructures with Anodic Alumina Oxide Templates, Characterization and Biofilm Development Test for Staphylococcus epidermidis.

    PubMed

    Desrousseaux, Camille; Cueff, Régis; Aumeran, Claire; Garrait, Ghislain; Mailhot-Jensen, Bénédicte; Traoré, Ousmane; Sautou, Valérie

    2015-01-01

    Medical devices can be contaminated by microbial biofilm which causes nosocomial infections. One of the strategies for the prevention of such microbial adhesion is to modify the biomaterials by creating micro or nanofeatures on their surface. This study aimed (1) to nanostructure acrylonitrile-butadiene-styrene (ABS), a polymer composing connectors in perfusion devices, using Anodic Alumina Oxide templates, and to control the reproducibility of this process; (2) to characterize the physico-chemical properties of the nanostructured surfaces such as wettability using captive-bubble contact angle measurement technique; (3) to test the impact of nanostructures on Staphylococcus epidermidis biofilm development. Fabrication of Anodic Alumina Oxide molds was realized by double anodization in oxalic acid. This process was reproducible. The obtained molds present hexagonally arranged 50 nm diameter pores, with a 100 nm interpore distance and a length of 100 nm. Acrylonitrile-butadiene-styrene nanostructures were successfully prepared using a polymer solution and two melt wetting methods. For all methods, the nanopicots were obtained but inside each sample their length was different. One method was selected essentially for industrial purposes and for better reproducibility results. The flat ABS surface presents a slightly hydrophilic character, which remains roughly unchanged after nanostructuration, the increasing apparent wettability observed in that case being explained by roughness effects. Also, the nanostructuration of the polymer surface does not induce any significant effect on Staphylococcus epidermidis adhesion.

  20. Fabrication of Acrylonitrile-Butadiene-Styrene Nanostructures with Anodic Alumina Oxide Templates, Characterization and Biofilm Development Test for Staphylococcus epidermidis

    PubMed Central

    Desrousseaux, Camille; Cueff, Régis; Aumeran, Claire; Garrait, Ghislain; Mailhot-Jensen, Bénédicte; Traoré, Ousmane; Sautou, Valérie

    2015-01-01

    Medical devices can be contaminated by microbial biofilm which causes nosocomial infections. One of the strategies for the prevention of such microbial adhesion is to modify the biomaterials by creating micro or nanofeatures on their surface. This study aimed (1) to nanostructure acrylonitrile-butadiene-styrene (ABS), a polymer composing connectors in perfusion devices, using Anodic Alumina Oxide templates, and to control the reproducibility of this process; (2) to characterize the physico-chemical properties of the nanostructured surfaces such as wettability using captive-bubble contact angle measurement technique; (3) to test the impact of nanostructures on Staphylococcus epidermidis biofilm development. Fabrication of Anodic Alumina Oxide molds was realized by double anodization in oxalic acid. This process was reproducible. The obtained molds present hexagonally arranged 50 nm diameter pores, with a 100 nm interpore distance and a length of 100 nm. Acrylonitrile-butadiene-styrene nanostructures were successfully prepared using a polymer solution and two melt wetting methods. For all methods, the nanopicots were obtained but inside each sample their length was different. One method was selected essentially for industrial purposes and for better reproducibility results. The flat ABS surface presents a slightly hydrophilic character, which remains roughly unchanged after nanostructuration, the increasing apparent wettability observed in that case being explained by roughness effects. Also, the nanostructuration of the polymer surface does not induce any significant effect on Staphylococcus epidermidis adhesion. PMID:26284922

  1. Acrylonitrile potentiates hearing loss and cochlear damage induced by moderate noise exposure in rats

    SciTech Connect

    Pouyatos, BenoIt . E-mail: benoit.pouyatos@med.va.gov; Gearhart, Caroline A.; Fechter, Laurence D.

    2005-04-01

    The diversity of chemical and drugs that can potentiate noise-induced hearing loss (NIHL) has impeded efforts to predict such interactions. We have hypothesized that chemical contaminants that disrupt intrinsic antioxidant defenses hold significant risk for potentiating NIHL. If this is true, then acrylonitrile (ACN) would be expected to potentiate NIHL. ACN, one of the 50 most commonly used chemicals in the United States, is metabolized via two pathways that are likely to disrupt intrinsic reactive oxygen species (ROS) buffering systems: (1) it conjugates glutathione, depleting this important antioxidant rapidly; (2) a second pathway involves the formation of cyanide, which can inhibit superoxide dismutase. We hypothesized that moderate noise exposure, that does not produce permanent hearing loss by itself, could initiate oxidative stress and that ACN could render the inner ear more sensitive to noise by disrupting intrinsic antioxidant defenses. Temporary and persistent effects of ACN alone (50 mg/kg, sc 5 days), noise alone (95 or 97 dB octave band noise, 4 h/day for 5 days), or ACN in combination with noise were determined using distortion product otoacoustic emissions (DPOAEs) and compound action potential (CAP) amplitudes. Histopathological damage to hair cells resulting from these treatments was also investigated using surface preparations of the organ of Corti. Individually, neither ACN nor noise exposures caused any permanent hearing or hair cell loss; only a reversible temporary threshold shift was measured in noise-exposed animals. However, when given in combination, ACN and noise induced permanent threshold shifts (13-16 dB between 7 and 40 kHz) and a decrease in DPOAE amplitudes (up to 25 dB at 19 kHz), as well as significant outer hair cell (OHC) loss (up to 20% in the first row between 13 and 47 kHz). This investigation demonstrates that ACN can potentiate NIHL at noise levels that are realistic in terms of human exposure, and that the OHCs are the

  2. Artifact-free measurement of residual dipolar couplings in DMSO by the use of cross-linked perdeuterated poly(acrylonitrile) as alignment medium.

    PubMed

    Kummerlöwe, Grit; Behl, Marc; Lendlein, Andreas; Luy, Burkhard

    2010-11-21

    Perdeuterated poly(acrylonitrile) is introduced as a practically proton-free alignment medium for the measurement of anisotropic NMR parameters; its use in conventional glass tubes and in a Kalrez® 8002 UP-based stretching device with resulting spectra of astonishing quality are demonstrated.

  3. Accurate quantification of the mercapturic acids of acrylonitrile and its genotoxic metabolite cyanoethylene-epoxide in human urine by isotope-dilution LC-ESI/MS/MS.

    PubMed

    Schettgen, T; Bertram, J; Kraus, T

    2012-08-30

    Acrylonitrile is a highly important industrial chemical with a high production volume worldwide, especially in the plastics industry. It is classified as a possible human carcinogen by the International Agency for Research on Cancer (IARC group 2B). During metabolism of acrylonitrile, the genotoxic metabolite cyanoethylene-epoxide is formed. The urinary mercapturic acids of acrylonitrile, namely N-acetyl-S-(2-cyanoethyl)-L-cysteine (CEMA) and cyanoethylene-epoxide, namely N-acetyl-S-(1-cyano-2-hydroxyethyl)-L-cysteine (CHEMA) are specific biomarkers for the determination of individual internal exposure to acrylonitrile and its highly reactive metabolite. We have developed and validated a sensitive method for the accurate determination of CEMA and CHEMA in human urine with a multidimensional LC/MS/MS-method using deuterium-labelled analogues for both analytes as internal standards. Analytes were stripped from urinary matrix by online extraction on a restricted access material, transferred to the analytical column and determined by tandem mass spectrometry. The limit of quantification (LOQ) for CEMA and CHEMA was 1 μg/L urine and allowed to quantify the background exposure of the (smoking) general population. Precision within and between series for CHEMA ranged from 2.6 to 8.0% at four concentrations ranging from 8.3 to 86 μg/L urine, mean accuracy was between 94 and 100%. For CEMA, precision within and between series ranged from 2.4 to 14.5% at four concentrations ranging from 15.1 to 196 μg/L urine, mean accuracy was between 91 and 104%. We applied the method to spot urine samples of 83 subjects of the general population with no known occupational exposure to acrylonitrile. Median levels (range) for CEMA and CHEMA in urine samples of non-smokers (n=47) were 1.9 μg/L (<1-16.4 μg/L) and<1 μg/L (<1-3 μg/L), while in urine samples of smokers (n=36), median levels were 184 μg/L (2-907 μg/L) and 29.3 μg/L (<1-147 μg/L), respectively. Smokers showed a

  4. Immunotoxic effects of sodium tungstate dihydrate on female B6C3F1/N mice when administered in drinking water.

    PubMed

    Frawley, Rachel P; Smith, Matthew J; White, Kimber L; Elmore, Susan A; Herbert, Ron; Moore, Rebecca; Staska, Lauren M; Behl, Mamta; Hooth, Michelle J; Kissling, Grace E; Germolec, Dori R

    2016-09-01

    Tungsten is a naturally occurring, high-tensile strength element that has been used in a number of consumer products. Tungsten has been detected in soil, waterways, groundwater, and human tissue and body fluids. Elevated levels of tungsten in urine were reported for populations exposed to tungstate in drinking water in areas where natural tungsten formations were prevalent. Published reports indicated that sodium tungstate may modulate hematopoiesis, immune cell populations, and immune responses in rodent models. The objective of this study was to assess potential immunotoxicity of sodium tungstate dihydrate (STD), a drinking water contaminant. Female B6C3F1/N mice received 0-2000 mg STD/L in their drinking water for 28 d, and were evaluated for effects on immune cell populations in spleen and bone marrow, and humoral-mediated, cell-mediated, and innate immunity. Three different parameters of cell-mediated immunity were similarly affected at 1000 mg STD/L. T-cell proliferative responses against allogeneic leukocytes and anti-CD3 were decreased 32%, and 21%, respectively. Cytotoxic T-lymphocyte activity was decreased at all effector:target cell ratios examined. At 2000 mg STD/L, the absolute numbers of CD3(+) T-cell progenitor cells in bone marrow were increased 86%, but the alterations in B-lymphocyte and other progenitor cells were not significant. There were no effects on bone marrow DNA synthesis or colony forming capabilities. STD-induced effects on humoral-mediated immunity, innate immunity, and splenocyte sub-populations were limited. Enhanced histopathology did not detect treatment-related lesions in any of the immune tissues. These data suggest exposure to STD in drinking water may adversely affect cell-mediated immunity. PMID:27223060

  5. Immunotoxic effects of sodium tungstate dihydrate on female B6C3F1/N mice when administered in drinking water.

    PubMed

    Frawley, Rachel P; Smith, Matthew J; White, Kimber L; Elmore, Susan A; Herbert, Ron; Moore, Rebecca; Staska, Lauren M; Behl, Mamta; Hooth, Michelle J; Kissling, Grace E; Germolec, Dori R

    2016-09-01

    Tungsten is a naturally occurring, high-tensile strength element that has been used in a number of consumer products. Tungsten has been detected in soil, waterways, groundwater, and human tissue and body fluids. Elevated levels of tungsten in urine were reported for populations exposed to tungstate in drinking water in areas where natural tungsten formations were prevalent. Published reports indicated that sodium tungstate may modulate hematopoiesis, immune cell populations, and immune responses in rodent models. The objective of this study was to assess potential immunotoxicity of sodium tungstate dihydrate (STD), a drinking water contaminant. Female B6C3F1/N mice received 0-2000 mg STD/L in their drinking water for 28 d, and were evaluated for effects on immune cell populations in spleen and bone marrow, and humoral-mediated, cell-mediated, and innate immunity. Three different parameters of cell-mediated immunity were similarly affected at 1000 mg STD/L. T-cell proliferative responses against allogeneic leukocytes and anti-CD3 were decreased 32%, and 21%, respectively. Cytotoxic T-lymphocyte activity was decreased at all effector:target cell ratios examined. At 2000 mg STD/L, the absolute numbers of CD3(+) T-cell progenitor cells in bone marrow were increased 86%, but the alterations in B-lymphocyte and other progenitor cells were not significant. There were no effects on bone marrow DNA synthesis or colony forming capabilities. STD-induced effects on humoral-mediated immunity, innate immunity, and splenocyte sub-populations were limited. Enhanced histopathology did not detect treatment-related lesions in any of the immune tissues. These data suggest exposure to STD in drinking water may adversely affect cell-mediated immunity.

  6. Development and validation of personal monitoring methods for low levels of acrylonitrile in workplace atmosphere. II. Thermal desorption and field validation

    SciTech Connect

    Borders, R.A.; Gluck, S.J.; Sowle, W.F.; Melcher, R.G.

    1986-03-01

    Thermal desorption is a more sensitive alternative to solvent desorption for the determination of acrylonitrile in air. A dual-bed collection tube (Tenax GC and Carbosieve B) was developed for collecting and concentrating low levels of acrylonitrile. Two thermal desorption techniques were evaluated for the recovery of acrylonitrile collected on the dual-bed tubes over a concentration range from 0.05 to 5 ppm. A commercially-available system, the Century Programmable Thermal Desorption Unit, was easy to operate, allowed for multiple injections of the sample and had a recovery of 82 +/- 12% (RSD). Sampled were stored for up to two months without affecting the recovery and there was not an observable effect from humidity or from the presence of other organic compounds. This system was found to have limitations at acrylonitrile concentrations above 1 ppm. A field validation study tested the sampling and analytical methods developed for monitoring low levels of acrylonitrile in the workplace. Three methods employing Pittsburgh Coconut-Base activated charcoal, Ambersorb XE-348 and Tenax-GC and Carbosieve B sampling mediums were validated for concentrations ranging from 0.05 to 5 ppm and confirmed in the field from 0.02 to 3 ppm in tests conducted at plant sites. These field studies were run over varying humidity and temperature conditions. The overall absolute recoveries and relative standard deviations found for these methods found during the field trials are 90 +/- 18% for charcoal; 85 +/- 11% for Ambersorb XE-348; and 90 +/- 19% for the Century dual-bed sorbent. These values were in quite good agreement with the 91 +/- 10%, 88 +/- 8%, and 82 +/- 12% determined in laboratory studies.

  7. Development of radiopure cadmium tungstate crystal scintillators from enriched {sup 106}Cd and {sup 116}Cd to search for double beta decay

    SciTech Connect

    Danevich, F. A.; Boiko, R. S.; Chernyak, D. M.; Kobychev, V. V.; Kropivyansky, B. N.; Mokina, V. M.; Nikolaiko, A. S.; Poda, D. V.; Podviyanuk, R. B.; Tretyak, V. I.; Barabash, A. S.; Konovalov, S. I.; Umatov, V. I.; Belli, P.; Bernabei, R.; D'Angelo, S.; Brudanin, V. B.; Cappella, F.; Incicchitti, A.; Caracciolo, V.; and others

    2013-08-08

    Cadmium tungstate crystal scintillators enriched in {sup 106}Cd up to 66% ({sup 106}CdWO{sub 4}) and in {sup 116}Cd up to 82% ({sup 116}CdWO{sub 4}) have been developed. The low radioactive contamination of the crystals measured on the level of ≤ 1.5 mBq/kg ({sup 40}K), ≤ 0.005 - 0.012 mBq/kg ({sup 226}Ra), 0.04 - 0.07 mBq/kg ({sup 228}Th) allows to carry out high sensitivity experiments to search for double beta processes in {sup 106}Cd and {sup 116}Cd.

  8. Kinetic approach to evaluate the energy and entropy of activation for the exchange of alkaline earth metal ions on tin(IV) tungstate cation exchanger

    SciTech Connect

    Varshney, K.G.; Khan, A.A.; Varshney, K.; Agrawal, S.

    1984-01-01

    A new approach based on the Nernst-Planck equations has been applied to study the reaction kinetics on the surface of tin(IV) tungstate for the Mg(II)-H(I), Ca(II)-H(I), Sr(II)-H(I) and Ba(II)-H(I) exchanges under the conditions favouring a particle diffusion phenomenon. On the basis of these studies the various physical parameters such as the effective diffusion coefficients, activation energies and entropies of activation have been evaluated which give some informations regarding the mechanism of ion-exchange on the surface of inorganic materials. 25 references, 3 figures, 3 tables.

  9. The potential reproductive, neurobehavioral and systemic effects of soluble sodium tungstate exposure in Sprague-Dawley rats

    SciTech Connect

    McInturf, S.M.; Bekkedal, M.Y.V.; Wilfong, E.; Arfsten, D.; Chapman, G.; Gunasekar, P.G.

    2011-07-15

    The debate on tungsten (W) is fostered by its continuous usage in military munitions. Reports demonstrate W solubilizes in soil and can migrate into drinking water supplies and, therefore, is a potential health risk to humans. This study evaluated the reproductive, systemic and neurobehavioral effects of sodium tungstate (NaW) in rats following 70 days of daily pre-and postnatal exposure via oral gavage to 5, 62.5 and 125 mg/kg/day of NaW through mating, gestation and weaning (PND 0-20). Daily administration of NaW produced no overt evidence of toxicity and had no apparent effect on mating success or offspring physical development. Distress vocalizations were elevated in F{sub 1} offspring from the high dose group, whereas righting reflex showed unexpected sex differences where males demonstrated faster righting than females; however, the effects were not dose-dependent. Locomotor activity was affected in both low and high-dose groups of F{sub 1} females. Low-dose group showed increased distance traveled, more time in ambulatory movements and less time in stereotypic behavior than controls or high dose animals. The high-dose group had more time in stereotypical movements than controls, and less time resting than controls and the lowest exposure group. Maternal retrieval was not affected by NaW exposure. Tungsten analysis showed a systemic distribution of NaW in both parents and offspring, with preferential uptake within the immune organs, including the femur, spleen and thymus. Histopathological evidence suggested no severe chronic injury or loss of function in these organs. However, the heart showed histological lesions, histiocytic inflammation from minimal to mild with cardiomyocyte degeneration and necrosis in several P{sub 0} animals of 125 mg NaW dose group. The result of this study suggests that pre and postnatal exposure to NaW may produce subtle neurobehavioral effects in offspring related to motor activity and emotionality.

  10. Effect of reactive compatibilization on the morphology and physical properties of bisphenol-A-polycarbonate/acrylonitrile-butadiene-styrene blends

    NASA Astrophysics Data System (ADS)

    Wildes, Gregg Stephen

    1998-11-01

    An amine functional styrene-acrylonitrile (SAN-amine) polymer is proposed as a reactive compatibilizer for bisphenol-A-polycarbonate/acrylonitrile-butadiene-styrene (PC/ABS) blends. This polymer is miscible with the styrene/acrylonitrile (SAN) copolymer matrix of ABS materials, and the pendant secondary amine groups react with PC at the carbonate linkage to form a SAN-g-PC copolymer. The graft copolymer molecules reside at the PC/ABS interface and provide improved morphological stability at elevated temperatures by suppressing phase coalescence. The synthesis of this reactive compatibilizer and its reaction with carbonate moieties is described. Characterization of this reaction was done by NMR and GPC using model secondary amine and carbonate containing compounds. A technique was developed for the quantitative measurement of the kinetics of dispersed phase particle coalescence in these blends; the morphology was examined using TEM. While uncompatibilized PC/SAN blends showed an increase in particle size from approximately 1 mum to 2 mum (depending on PC viscosity) in less than five minutes at 270sp°C; compatibilized blends containing as little as 1% SAN-amine exhibited no change in morphology after 20 minutes. The effects of dispersed phase concentration, viscosity ratio and interfacial compatibilization using the SAN-amine compatibilizer on the process induced morphology of PC/SAN blends were also examined. Dispersed phase particle size increased significantly with SAN concentration and, although the morphology of uncompatibilized PC/SAN blends mixed in a Brabender mixer, single and twin screw extruders were quite similar, the twin screw extruder produced significantly finer morphologies in blends containing SAN-amine. The average particle size for blends compatibilized with the SAN-amine polymer was approximately half that of uncompatibilized blends and was relatively independent of viscosity ratio and dispersed phase composition. The fracture of thin (3.18 mm

  11. Copolymers of acrylonitrile with quaternizable thiazole and triazole side-chain methacrylates as potent antimicrobial and hemocompatible systems.

    PubMed

    Tejero, Rubén; Gutiérrez, Beatriz; López, Daniel; López-Fabal, Fátima; Gómez-Garcés, José L; Fernández-García, Marta

    2015-10-01

    A series of six copolymeric families, P(AN-co-MTAs) with various molar fractions of acrylonitrile (fAN) and methacrylates (fMTA) based on 1,3-thiazole and 1,2,3-triazole pendant groups with several spacers of different length and nature (alkyl or succinic), have been synthesized by conventional radical polymerization. The molar fraction of acrylonitrile in the copolymers (FAN) was determined by CHNS elemental analysis. The copolymers were also characterized by ATR-FTIR and molecular weights were determined by size exclusion chromatography (SEC). Due to the nucleophilic nature of the azole heterocycles the copolymers have been easily modified by N-alkylation reaction with butyl iodide leading to polyelectrolytes of diverse amphiphilic balance, P(AN-co-MTAs-BuI). The degree of quaternization (DQ) was quantitative in all instances and was determined by (1)H NMR spectroscopy. Dynamic light scattering (DLS) measurements were performed in order to determine the particle size and the charge density of the systems. The antimicrobial activity of the copolymers was studied in terms of minimal inhibitory concentration (MIC) against the Gram-positive bacteria Staphylococcus aureus, the Gram-negative Pseudomonas aeruginosa and the yeast Candida parapsilosis, as well as the cytotoxic activity toward human red blood cells (RBCs). These types of amphiphilic copolycations presented high selectivity (>300) maintaining moderate to good antimicrobial activity (MIC=4-64 μg/mL) and being non-hemolytic even at high molar fractions of AN in the copolymers compared to PMTAs-BuI homopolymers. Moreover, two examples of acrylonitrile-enriched copolymers (FAN=0.6) presented an excellent time-killing efficiency against microorganisms with 99.9% of killing ranging from 5 to 30 min. Besides, important changes in the morphology of the cell envelop of the microorganisms after treatment with P(AN-co-MTAs) were observed by Field Emission Scanning Electron Microscopy (FE-SEM) compared to untreated

  12. Use of Yb-based catalyst for AGET ATRP of acrylonitrile to simultaneously control molecular mass distribution and tacticity.

    PubMed

    Ma, Jing; Chen, Hou; Zhang, Min; Wang, Chunhua; Zhang, Ying; Qu, Rongjun

    2012-08-01

    Yb-based catalyst was used for the first time for atom transfer radical polymerization using activators generated by electron transfer (AGET ATRP) of acrylonitrile (AN) with 2-bromopropionitrile (BPN) as initiator, 2, 2'-bipyridine (bipy) as ligand, and tisn(II) bis(2-ethylhexanoate) (Sn(EH)2) as reducing agent in the presence of air. With respect to AGET ATRP of AN catalyzed by CuBr2, an evident increase of polymer tacticity was observed for AGET ATRP of AN. The increase of syndiotacticity became more and more pronounced than the increase of isotacticity of polyacrylonitrile (PAN) along with YbBr3 content. The block copolymer PAN-b-PMMA with molecular weight at 60,000 and polydispersity at 1.36 was successfully prepared. PMID:24364980

  13. Dynamics of phase separation in poly(acrylonitrile-butadiene-styrene)-modified epoxy/DDS system: kinetics and viscoelastic effects.

    PubMed

    Jyotishkumar, P; Özdilek, Ceren; Moldenaers, Paula; Sinturel, Christophe; Janke, Andreas; Pionteck, Jürgen; Thomas, Sabu

    2010-10-28

    The dynamics of phase separation and final morphologies of poly(acrylonitrile-butadiene-styrene) (ABS)-modified epoxy system based on diglycidyl ether of bisphenol A (DGEBA) cured with 4,4'-diaminodiphenylsulfone (DDS) have been monitored in situ throughout the entire curing process by using optical microscopy (OM), differential scanning calorimetry (DSC), rheometry, and small-angle laser light scattering (SALLS). The evolution of phase separation and final morphologies with substructures were explored by OM. The final morphologies of the blend cured at 150 and 165 °C are of phase-inverted type and are quite different from the final morphologies of the same blend cured at 180 °C, in which the final morphologies are cocontinuous. AFM observations of the fully cured sample confirmed the existence of three different phases, the epoxy continuous phase, SAN (styrene/acrylonitrile) continuous phase, and PB droplets at the interface, with a strong tendency to stay at SAN continuous phase. Furthermore, the continuous epoxy phase contains SAN particles and the continuous SAN phase contains epoxy particles. Cure kinetics and rheological results correspond well with the viscoelastic phase separation revealed by OM. The SALLS results display clearly that the phase separation takes place according to nucleation and growth mechanism followed by spinodal decomposition. The development of light scattering patterns during the second stage phase separation follows the Cahn-Hilliard model of spinodal demixing. Furthermore, the evolution of the scattering vector follows a Maxwell-type relaxation equation establishing the viscoelastic behavior of phase separation. The relaxation time of phase separation can be described by the Williams-Landel-Ferry equation for viscoelasticity. As a whole, the dependence of phase separation on cure temperature and the development of final morphologies and the associated mechanisms were explored in detail for the complex epoxy/ABS system. PMID

  14. Environmentally benign electroless nickel plating using supercritical carbon-dioxide on hydrophilically modified acrylonitrile-butadiene-styrene

    NASA Astrophysics Data System (ADS)

    Tengsuwan, Siwach; Ohshima, Masahiro

    2014-08-01

    Electroless Ni-P plating using supercritical carbon dioxide (scCO2) in conjunction with copolymer-based hydrophilic modification was applied to an acrylonitrile-butadiene-styrene (ABS) substrate. The surface of ABS substrate was hydrophilically modified by blending with a multi-block copolymer, poly(ether-ester-amide)s (PEEA), in injection molding process. The substrate was then impregnated with Pd(II)-hexafluoroacetylacetonate, Pd(hfa)2, using scCO2, followed by the electroless plating reaction. ABS/PEEA substrates with different PEEA to ABS blend ratios and different volume ratios of butadiene to the styrene-acrylonitrile copolymer (SAN) matrix were prepared to investigate how the dispersed PEEA and butadiene domains affected the blend morphology and the adhesive strength of the plating metal-to-polymer contact. Increasing the PEEA copolymer to ABS blend ratio increased the mass transfer rate of the plating solution in the ABS substrate. Consequently, the metal-polymer composite layer became thicker, which increased the adhesive strength of the metal-to-polymer contact because of the anchoring effect. The butadiene domains appeared to attract the Pd catalyst precursor, and thus, the proportion of butadiene in the ABS matrix also affected the adhesive strength of the contact between the metal layer and the substrate. The ABS substrate was successfully plated with a Ni-P metal layer with an average adhesive strength of 9.1 ± 0.5 N cm-1 by choosing appropriate ABS/PEEA blend ratios and a Pd(hfa)2 concentration.

  15. Theoretical and experimental investigations of the 2-(4-chlorophenyl)-3-{[5-(2-cyano-2-phenylethenyl)]furan-2-yl}acrylonitrile molecule as a potential acceptor in organic solar cells

    NASA Astrophysics Data System (ADS)

    Kazici, Mehmet; Bozar, Sinem; Aydin Yuksel, Sureyya; Ongul, Fatih; Gokce, Halil; Gunes, Serap; Yorur Goreci, Cigdem

    2016-06-01

    A novel soluble asymmetric acrylonitrile derivative, 2-(4-Chlorophenyl)-3-{[5-(2-cyano-2-phenylethenyl)]furan-2-yl}acrylonitrile (CPCPFA, 3) was synthesized in three steps by Knoevenagel condensation. The structure of the CPCPFA was characterized using UV-vis, FTIR, 1H NMR, 13C NMR, and LC-MS. CPCPFA was evaluated as an electron acceptor in bulk heterojunction organic solar cells. Its optical and electronic properties as well as photovoltaic performance were investigated.

  16. Development and validation of personal monitoring methods for low levels of acrylonitrile in workplace atmosphere. I. Test atmosphere generation and solvent desorption methods

    SciTech Connect

    Melcher, R.G.; Borders, R.A.; Coyne, L.B.

    1986-03-01

    The purpose of this study was to optimize monitoring methods and to investigate new technology for the determination of low levels of acrylonitrile (0.05 to 5 ppm) in workplace atmospheres. In the first phase of the study, a dynamic atmosphere generation system was developed to produce low levels of acrylonitrile in simulated workplace atmospheres. Various potential sorbents were investigated in the second phase, and the candidate methods were compared in a laboratory validation study over a concentration range from 0.05 to 5 ppm acrylonitrile in the presence of potential interferences and under relative humidity conditions from 30% to 95% RH. A collection tube containing 600 mg Pittsburgh coconut base charcoal was found to be the optimum tube for sampling for a full 8 -hr shift. No breakthrough was observed over the concentrations and humidities tested. The recovery was 91.3% with a total relative precision of +/-21% over the test range, and the recovery was not affected by storage for up to five weeks.

  17. Acute and chronic effects of sodium tungstate on an aquatic invertebrate (Daphnia magna), green alga (Pseudokirchneriella subcapitata), and zebrafish (Danio rerio).

    PubMed

    Clements, Leslie N; Lemus, Ranulfo; Butler, Alicia D; Heim, Kate; Rebstock, Matthew R; Venezia, Carmen; Pardus, Michael

    2012-10-01

    Although aquatic toxicity data exists for tungstate substances, insufficient data of high quality and relevancy are available for conducting an adequate risk assessment. Therefore, a series of acute and chronic toxicity tests with sodium tungstate (Na(2)WO(4)) were conducted on an aquatic invertebrate (Daphnia magna), green alga (Pseudokirchneriella subcapitata), and zebrafish (Danio rerio). Collectively, the data from these studies suggest that sodium tungstate exhibits a relatively low toxicity to these taxa under these test conditions. All studies were conducted in the same laboratory under good laboratory practice standards using Organisation for Economic Co-operation and Development guidelines with the same stock of test material and the same analytical methods. All results are reported as mg W/L. The following toxicity values were based on mean measured concentrations. For D. magna, the 21 day test no-observable effect concentration (NOEC) was 25.9 mg W/L, and the 48-h median effective concentration (EC(50)) from the acute test was >95.5 mg W/L (the highest concentration tested). The P. subcapitata test yielded an ErC(50) of 31 mg W/L. A 38-day test with zebrafish resulted in an NOEC ≥5.74 mg W/L with no effects at any concentration. The 96-h LC(50) from the acute test with zebrafish was >106 mg W/L. The results of the current acute study for daphnids and fish are consistent with published literature, whereas the algae results are different from previously reported values. Transformation/dissolution (T/D) studies, which were conducted according to United Nations Globally Harmonized System of Classification and Labelling of Chemicals protocol, confirmed that the WO (4) (-2) anion accounted for most of the tungsten in solution. For classification purposes, the algae ecotoxity reference value was then compared with T/D data and would not classify Na(2)WO(4) as an aquatic toxicant under the European Union Classification, Labelling and Packaging scheme. PMID

  18. Acute and chronic effects of sodium tungstate on an aquatic invertebrate (Daphnia magna), green alga (Pseudokirchneriella subcapitata), and zebrafish (Danio rerio).

    PubMed

    Clements, Leslie N; Lemus, Ranulfo; Butler, Alicia D; Heim, Kate; Rebstock, Matthew R; Venezia, Carmen; Pardus, Michael

    2012-10-01

    Although aquatic toxicity data exists for tungstate substances, insufficient data of high quality and relevancy are available for conducting an adequate risk assessment. Therefore, a series of acute and chronic toxicity tests with sodium tungstate (Na(2)WO(4)) were conducted on an aquatic invertebrate (Daphnia magna), green alga (Pseudokirchneriella subcapitata), and zebrafish (Danio rerio). Collectively, the data from these studies suggest that sodium tungstate exhibits a relatively low toxicity to these taxa under these test conditions. All studies were conducted in the same laboratory under good laboratory practice standards using Organisation for Economic Co-operation and Development guidelines with the same stock of test material and the same analytical methods. All results are reported as mg W/L. The following toxicity values were based on mean measured concentrations. For D. magna, the 21 day test no-observable effect concentration (NOEC) was 25.9 mg W/L, and the 48-h median effective concentration (EC(50)) from the acute test was >95.5 mg W/L (the highest concentration tested). The P. subcapitata test yielded an ErC(50) of 31 mg W/L. A 38-day test with zebrafish resulted in an NOEC ≥5.74 mg W/L with no effects at any concentration. The 96-h LC(50) from the acute test with zebrafish was >106 mg W/L. The results of the current acute study for daphnids and fish are consistent with published literature, whereas the algae results are different from previously reported values. Transformation/dissolution (T/D) studies, which were conducted according to United Nations Globally Harmonized System of Classification and Labelling of Chemicals protocol, confirmed that the WO (4) (-2) anion accounted for most of the tungsten in solution. For classification purposes, the algae ecotoxity reference value was then compared with T/D data and would not classify Na(2)WO(4) as an aquatic toxicant under the European Union Classification, Labelling and Packaging scheme.

  19. Melt-processable hydrophobic acrylonitrile-based copolymer systems with adjustable elastic properties designed for biomedical applications.

    PubMed

    Cui, J; Trescher, K; Kratz, K; Jung, F; Hiebl, B; Lendlein, A

    2010-01-01

    Acrylonitrile-based polymer systems (PAN) are comprehensively explored as versatile biomaterials having various potential biomedical applications, such as membranes for extra corporal devices or matrixes for guided skin reconstruction. The surface properties (e.g. hydrophilicity or charges) of such materials can be tailored over a wide range by variation of molecular parameters such as different co-monomers or their sequence structure. Some of these materials show interesting biofunctionalities such as capability for selective cell cultivation. So far, the majority of AN-based copolymers, which were investigated in physiological environments, were processed from the solution (e.g. membranes), as these materials are thermo-sensitive and might degrade when heated. In this work we aimed at the synthesis of hydrophobic, melt-processable AN-based copolymers with adjustable elastic properties for preparation of model scaffolds with controlled pore geometry and size. For this purpose a series of copolymers from acrylonitrile and n-butyl acrylate (nBA) was synthesized via free radical copolymerisation technique. The content of nBA in the copolymer varied from 45 wt% to 70 wt%, which was confirmed by 1H-NMR spectroscopy. The glass transition temperatures (Tg) of the P(AN-co-nBA) copolymers determined by differential scanning calorimetry (DSC) decreased from 58 degrees C to 20 degrees C with increasing nBA-content, which was in excellent agreement with the prediction of the Gordon-Taylor equation based on the Tgs of the homopolymers. The Young's modulus obtained in tensile tests was found to decrease significantly with rising nBA-content from 1062 MPa to 1.2 MPa. All copolymers could be successfully processed from the melt with processing temperatures ranging from 50 degrees C to 170 degrees C, whereby thermally induced decomposition was only observed at temperatures higher than 320 degrees C in thermal gravimetric analysis (TGA). Finally, the melt processed P

  20. Synthesis, structural and vibrational studies on mixed alkali metal gadolinium double tungstate, K1-xNaxGd(WO4)2

    NASA Astrophysics Data System (ADS)

    Durairajan, A.; Thangaraju, D.; Moorthy Babu, S.

    2013-02-01

    Mixed alkali double tungstates K1-xNaxGd(WO4)2 (KNGW) (0 ⩽ x ⩽ 1) were synthesized by solid state reaction using sodium doped monoclinic KGd(WO4)2 (KGW). Synthesized KNGW powders were characterized using powder X-ray diffraction (XRD), differential thermal analysis (DTA), scanning electron microscopy (SEM) and Raman analysis. DTA analysis confirms that the melting point of the KGW matrix increases from 1063 °C to 1255 °C with increasing sodium content. The Powder XRD analyses reveal that mixed phases were observed up to 40 wt.% of Na in the KGW matrix above that percentage there is domination of scheelite structure in the synthesized powder. Polyhedral type, bi-pyramidal shape and spheroid shape morphology was observed for KGW, NKGW and NGW powders respectively. The Raman analysis was carried out to understand the vibrational characteristic changes with mixing of sodium ions in the KGW matrix.

  1. Synthesis and characterization of a novel hybrid nano composite cation exchanger poly-o-toluidine Sn(IV) tungstate: Its analytical applications as ion-selective electrode

    NASA Astrophysics Data System (ADS)

    Khan, Asif Ali; Shaheen, Shakeeba

    2013-02-01

    A novel organic-inorganic nano composite cation exchanger poly-o-toluidine Sn(IV) tungstate has been synthesized by incorporation of a polymer material into inorganic precipitate. The material is a class of hybrid ion-exchanger with good ion-exchange properties, reproducibility, stability and good selectivity for heavy metals. The physico-chemical properties of this nano composite material were characterized by using XRD, TGA, FTIR, SEM and TEM. The ion-exchange capacity, pH titrations, elution behavior and chemical stability were also carried out to study ion-exchange properties of the material. Distribution studies for various metal ions revealed that the nano composite is highly selective for Cd(II). An ion-selective membrane electrode was fabricated using this material for the determination of Cd(II) ions in solutions. The analytical utility of this electrode was established by employing it as an indicator electrode in electrometric titrations.

  2. Morphological evolution and visible light-induced degradation of Rhodamine 6G by nanocrystalline bismuth tungstate prepared using a template-based approach

    NASA Astrophysics Data System (ADS)

    Silva, Raissa Mendes; Batista Barbosa, Diego Augusto; de Jesus Silva Mendonça, Caritas; de Oliveira Lima, José Renato; Silva, Fernando Carvalho; Longo, Elson; Maciel, Adeilton Pereira; de Araujo Paschoal, Carlos William; Almeida, Marcio Aurélio Pinheiro

    2016-09-01

    The cleaning of water contaminated with organic dyes is a crucial problem nowadays. The search for good catalysts is intense, and bismuth tungstates have attracted a lot of attention because of their catalytic properties which are related to their crystal structure and morphology. In this study, we show that Bi2WO6 (BWO) crystals synthesized by the surfactant-assisted hydrothermal method create a different morphology than non-assisted crystals. With the assistance of the PVP surfactant, even the BWO crystalline structure could change, crystallizing into a high-symmetry metastable phase. These changes in morphology imply a decrease in BWO catalytic activity, which shows that insightful control of BWO synthesis is necessary to improve the BWO properties.

  3. PAPERS DEVOTED TO THE 90TH ANNIVERSARY OF A.M.PROKHOROV: Lasing properties of selectively pumped Raman-active Nd3+-doped molybdate and tungstate crystals

    NASA Astrophysics Data System (ADS)

    Basiev, Tasoltan T.; Doroshenko, Maxim E.; Ivleva, Lyudmila I.; Osiko, Vyacheslav V.; Kosmyna, M. B.; Komar', V. K.; Sulc, J.; Jelinkova, H.

    2006-08-01

    The lasing efficiency of Nd3+ ions is studied in laser materials capable of self-Raman frequency conversion. The lasing properties of tungstate and molybdate crystals with the scheelite structure (SrWO4, BaWO4, PbWO4, SrMoO4, PbMoO4) activated with neodymium ions are investigated upon longitudinal pumping by a 750-nm alexandrite laser or a 800-nm diode laser. The slope lasing efficiency obtained for a Nd3+:PbMoO4 laser emitting at 1054 nm is 54.3% for the total lasing efficiency of 46%, which is the best result for all the crystals with the scheelite structure studied so far. The simultaneous Q-switched lasing and self-Raman frequency conversion were demonstrated in neodymium-doped SrWO4, PbWO4, and BaWO4 crystals.

  4. Tungsten bronze-based nuclear waste form ceramics. Part 2: Conversion of granular microporous tungstate polyacrylonitrile (PAN) composite adsorbents to leach resistant ceramics

    NASA Astrophysics Data System (ADS)

    Griffith, Christopher S.; Sebesta, Ferdinand; Hanna, John V.; Yee, Patrick; Drabarek, Elizabeth; Smith, Mark E.; Luca, Vittorio

    2006-11-01

    Conversion of a granular molybdenum-doped, hexagonal tungsten bronze (MoW-HTB)-polyacrylonitrile (PAN) composite adsorbent to a leach resistant ceramic waste form capable of immobilizing adsorbed Cs + and Sr 2+ has been achieved by heating in air at temperatures in the range 600-1200 °C. Thermal treatment of the Cs- and Sr-loaded composite material at 1000 °C was sufficient to invoke a 60% reduction in volume of the composite while still retaining its spherical morphology. Cs-133 MAS NMR studies of this sample suite at 9.4 T and 14.1 T showed that multiple Cs sites are present throughout the entire thermal treatment range. Scanning electron microscopy investigations of the phase assemblages resulting from thermal treatment demonstrated that the full complement of Cs, and the majority of Sr, partitions into HTB phases (A 0.16-0.3MO 3; A = Cs +, Sr 2+ and Na +; M = Mo, W). The potentially reducing conditions resulting from the removal of the PAN matrix or the presence of high concentrations of Na + relative to either Cs + or Sr 2+ does not retard the formation of the high temperature HTB phases. The fraction of Cs + and Sr 2+ leached from the tungstate phase assemblages was superior or comparable with cesium hollandite (Cs 0.8Ba 0.4Ti 8O 18; f = ≈8 × 10 -5; rate = <1.2 × 10 -4 g/m 2/day) and strontium titanate (SrTiO 3; f = 3.1 × 10 -3; rate = 2.63 × 10 -4 g/m 2/day), respectively, using a modified PCT test in Millipore water at 90 °C. Furthermore, where aggressive leaching conditions were employed (0.1 M HNO 3; 150 °C; 4 days), the tungstate phase assemblages displayed leach resistance almost two orders of magnitude greater than the reference phases.

  5. Separation of polycarbonate and acrylonitrile-butadiene-styrene waste plastics by froth flotation combined with ammonia pretreatment.

    PubMed

    Wang, Chong-Qing; Wang, Hui; Liu, Qun; Fu, Jian-Gang; Liu, You-Nian

    2014-12-01

    The objective of this research is flotation separation of polycarbonate (PC) and acrylonitrile-butadiene-styrene (ABS) waste plastics combined with ammonia pretreatment. The PC and ABS plastics show similar hydrophobicity, and ammonia treatment changes selectively floatability of PC plastic while ABS is insensitive to ammonia treatment. The contact angle measurement indicates the dropping of flotation recovery of PC is ascribed to a decline of contact angle. X-ray photoelectron spectroscopy demonstrates reactions occur on PC surface, which makes PC surface more hydrophilic. Separation of PC and ABS waste plastics was conducted based on the flotation behavior of single plastic. At different temperatures, PC and ABS mixtures were separated efficiently through froth flotation with ammonia pretreatment for different time (13 min at 23 °C, 18 min at 18 °C and 30 min at 23 °C). For both PC and ABS, the purity and recovery is more than 95.31% and 95.35%, respectively; the purity of PC and ABS is up to 99.72% and 99.23%, respectively. PC and ABS mixtures with different particle sizes were separated effectively, implying that ammonia treatment possesses superior applicability.

  6. Radiolytic preparation and characterization of hydrophilic poly(acrylonitrile-co-vinylsulfonate)-grafted porous poly(tetrafluoroethylene) substrates

    NASA Astrophysics Data System (ADS)

    Park, Byeong-Hee; Sohn, Joon-Yong; Shin, Junhwa

    2016-01-01

    In this study, a hydrophilic copolymer of acrylonitrile (AN) and sodium vinylsulfonate (SVS) was grafted into a highly hydrophobic porous poly(tetrafluoroethylene) (PTFE) substrate using a gamma-ray irradiation method and the grafted substrate was used as a substrate for impregnating a hydrophilic ionomer, Nafion. The results of FT-IR and TGA analysis of the prepared substrate showed that the SVS/AN monomers were successfully grafted into the porous PTFE film. The results of degree of grafting, elemental analyzer, and contact angle analysis showed that the hydrophilicity of the prepared PTFE-g-P(AN-co-VS) substrate was increased with an increase in the amount of SVS/AN graft copolymers. Also, the results of FE-SEM and Gurley number measurement showed that the pores in the substrate were reduced as the amount of SVS/AN copolymers grafted into the substrate increased. The prepared porous PTFE-g-P(AN-co-VS) substrate at an irradiation dose of 70 kGy was found to impregnate Nafion ionomer effectively compared to the original porous PTFE substrate. These results suggest that the prepared PTFE-g-P(AN-co-VS) substrate can be effectively used for the impregnation of polymer electrolyte (Nafion) to prepare a reinforced composite membrane.

  7. Isolation of the epsilon-caprolactam denitrifying bacteria from a wastewater treatment system manufactured with acrylonitrile-butadiene-styrene resin.

    PubMed

    Wang, Chun-Chin; Lee, Chi-Mei

    2007-06-25

    epsilon-Caprolactam has high COD and toxicity, so its discharge to natural water and soil systems may lead to an adverse environmental effect on water quality, endangering public health and welfare. This investigation attempts to isolate epsilon-caprolactam denitrifying bacteria from a wastewater treatment system manufactured with acrylonitrile-butadiene-styrene (ABS) resin. The goal is to elucidate the effectiveness of isolated pure strain and ABS mixed strains in treating epsilon-caprolactam from synthetic wastewater. The results reveal that Paracoccus versutus MDC-3 was isolated from the wastewater treatment system manufactured with ABS resin. The ABS mixed strains and P. versutus MDC-3 can consume up to 1539mg/l epsilon-caprolactam to denitrify from synthetic wastewater. Complete epsilon-caprolactam removal depended on the supply of sufficient electron acceptors (nitrate). Strain P. versutus MDC-3, Hyphomicrobium sp. HM, Methylosinus pucelana and Magnetospirillum sp. CC-26 are related closely, according to the phylogenetic analyses of 16S rDNA sequences. PMID:17161908

  8. Reclamation of post-consumer plastics for development of polycarbonate and acrylonitrile butadiene styrene based nanocomposites with nanoclay

    NASA Astrophysics Data System (ADS)

    Zicans, Janis; Meri, Remo Merijs; Ivanova, Tatjana; Berzina, Rita; Saldabola, Ruuta; Maksimov, Robert

    2016-05-01

    Suitability of recycled acrylonitrile-butadiene-styrene (R-ABS) and recycled polycarbonate (R-PC) for the development of polymer matrix nanocomposites with organically modified nanoclay (OMMT) is evaluated in comparison to virgin polymers (V-ABS and V-PC) based systems. The influence of OMMT content on the structure as well as calorimetric, mechanical and thermal properties of virgin and recycled polymers containing systems is revealed. Increase in stiffness and strength of virgin and recycled polymers based systems is observed along with rising nanoclay content. However, it is observed that reinforcing efficiency of clays on the R-ABS containing systems is reduced to certain extent in comparison to those, based on virgin polymers. It is shown, that in the presence of OMMT approximation of glass transition temperatures of both polymeric components is observed, which can testify about certain improvement of compatibility between PC and ABS. Increment of the modulus of elasticity and yield strength of the nanocomposites is associated with anisodiametric shape of OMMT, as well as with intercalation of polymer within the interlaminar space of the clay nanoparticles. It is also demonstrated that addition of nanoclay improves thermogravimetric behavior of the investigated compositions. Consequently, it is suggested that nanoclays can be used as promising functional additives and replace halogenated flame-retardants, without reducing mechanical properties of the composites.

  9. Molecular mechanism of gelation upon the addition of water to a solution of poly(acrylonitrile) in dimethylsulfoxide

    NASA Astrophysics Data System (ADS)

    Vettegren, V. I.; Kulik, V. B.; Savitskii, A. V.; Fetisov, O. I.; Usov, V. V.

    2010-05-01

    The solidification of a solution of poly(acrylonitrile) (PAN) in dimethylsulfoxide (DMSO) upon introduction of water into the solution is studied by Raman spectroscopy. In the absence of water, DMSO molecules are found to produce dipole-dipole bonds with PAN molecules. Upon the introduction of water, DMSO molecules produce hydrogen bonds with it and bands at 1005 and 1015 cm-1 appear in the Raman spectrum, which are assigned to the valence vibrations of S=O bonds involved in the hydrogen bonds. Simultaneously, water molecules produce hydrogen bonds with PAN molecules: R-C≡N...H-O-H...N≡C-R, where R is the carbon skeleton of a PAN molecule. Accordingly, a band at 2250 cm-1 arises in the Raman spectrum, which is assigned to the valence vibrations of C≡N bonds producing hydrogen bonds with a water molecule. When the water content is low and the DMSO concentration is high, the length of the hydrogen bonds varies in wide limits and the band at 2250 cm-1 is wide. As the water content rises, DMSO molecules come out of PAN, the variation of the hydrogen bond length in it decreases (the band at 2250 cm-1 narrows), and a high-viscosity system (gel) arises that consists of PAN molecules bonded to water molecules via “equally strong” hydrogen bonds.

  10. Highly porous acrylonitrile-based submicron particles for UO2(2+) absorption in an immunosensor assay.

    PubMed

    Sahiner, Nurettin; Yu, Haini; Tan, Grace; He, Jibao; John, Vijay T; Blake, Diane A

    2012-01-01

    Our laboratory has previously reported an antibody-based assay for hexavalent uranium (UO(2)(2+)) that could be used on-site to rapidly assess uranium contamination in environmental water samples (Melton, S. J.; et al. Environ. Sci. Technol. 2009, 43, 6703-6709). To extend the utility of this assay to less-characterized sites of uranium contamination, we required a uranium-specific adsorbent that would rapidly remove the uranium from groundwater samples, while leaving the concentrations of other ions in the groundwater relatively unaltered. This study describes the development of hydrogel particles containing amidoxime groups that can rapidly and selectively facilitate the uptake of uranyl ions. A miniemulsion polymerization technique using SDS micelles was employed for the preparation of the hydrogel as linked submicrometer particles. In polymerization, acrylonitrile was used as the initial monomer, ethylene glycol dimethacrylate as the crosslinker and 2-hydroxymethacrylate, 1-vinyl-2-pyrrolidone, acrylic acid, or methacrylic acid were added as co-monomers after the initial seed polymerization of acrylonitrle. The particles were characterized by transmission electron spectroscopy, scanning electron microscopy (SEM) and cryo-SEM. The amidoximated particles were superior to a commercially available resin in their ability to rapidly remove dissolved UO(2)(2+) from spiked groundwater samples.

  11. Correlation Between Miscibility and Rheological Characteristics of the Polystyrene (PS) and Poly(styrene-co-acrylonitrile) (PSAN) Blends

    NASA Astrophysics Data System (ADS)

    Marwat, Zafrullah Khan; Baloch, Musa Kaleem

    2016-11-01

    Rheological measurement has been an effective technique to characterize the miscibility of polymer blends. This article investigates the viscoelastic behavior of poly(styrene) (PS) and poly(styrene-co-acrylonitrile) (PSAN) binary solutions in tetrahydrofuran (THF) relative to PS/PSAN/THF ternary solutions mainly reporting the findings of the authors involving the correlation between the miscibility and rheological behavior. Rheological properties, such as shear viscosity, and shear stress as a function of shear rate were investigated for different blend compositions. Moreover, complex viscosity, loss and storage moduli were also investigated as functions of both the frequency and blend composition. The criterion of miscibility based on the rule of mixture has been discussed. The present study revealed very small window of miscibility as only composition, 50/50 showed values close to the additivity rule or intermediate to those of the neat polymers, thereby indicating very weak interactions between the blend components. On the basis of various findings during the rheological investigation, the blend under study is classified almost immiscible. Moreover, the obtained results also suggested that the miscibility depends on the blend composition and frequency.

  12. Accurate ab initio prediction of propagation rate coefficients in free-radical polymerization: Acrylonitrile and vinyl chloride

    NASA Astrophysics Data System (ADS)

    Izgorodina, Ekaterina I.; Coote, Michelle L.

    2006-05-01

    A systematic methodology for calculating accurate propagation rate coefficients in free-radical polymerization was designed and tested for vinyl chloride and acrylonitrile polymerization. For small to medium-sized polymer systems, theoretical reaction barriers are calculated using G3(MP2)-RAD. For larger systems, G3(MP2)-RAD barriers can be approximated (to within 1 kJ mol -1) via an ONIOM-based approach in which the core is studied at G3(MP2)-RAD and the substituent effects are modeled with ROMP2/6-311+G(3df,2p). DFT methods (including BLYP, B3LYP, MPWB195, BB1K and MPWB1K) failed to reproduce the correct trends in the reaction barriers and enthalpies with molecular size, though KMLYP showed some promise as a low cost option for very large systems. Reaction rates are calculated via standard transition state theory in conjunction with the one-dimensional hindered rotor model. The harmonic oscillator approximation was shown to introduce an error of a factor of 2-3, and would be suitable for "order-of-magnitude" estimates. A systematic study of chain length effects indicated that rate coefficients had largely converged to their long chain limit at the dimer radical stage, and the inclusion of the primary substituent of the penultimate unit was sufficient for practical purposes. Solvent effects, as calculated using the COSMO model, were found to be relatively minor. The overall methodology reproduced the available experimental data for both of these monomers within a factor of 2.

  13. Removal of As(V), Cr(III) and Cr(VI) from aqueous environments by poly(acrylonitril-co-acrylamidopropyl-trimethyl ammonium chloride)-based hydrogels.

    PubMed

    Dudu, Tuba Ersen; Sahiner, Mehtap; Alpaslan, Duygu; Demirci, Sahin; Aktas, Nahit

    2015-09-15

    Cationic poly(Acrylonitril-co-Acrylamidopropyl-trimethyl Ammonium Chloride) (p(AN-co-APTMACl)) hydrogels in bulk were synthesized by using acrylonitrile (AN) and 3-acrylamidopropyl-trimethyl ammonium chloride (APTMACl) as monomers. The prepared hydrogels were exposed to amidoximation reaction to replace hydrophobic nitrile groups with hydrophilic amidoxime groups that have metal ion binding ability. Those replacements were increased the hydrogels absorption capacity for As(V) and Cr(VI). Langmuir and Freundlich isotherms equations were utilized to obtain the best-fitted isotherm model for the absorption of the ions at different metal ion concentrations. The absorption data of As(V) ion were fitted well to Freundlich isotherm while those of Cr(VI) and Cr(III) ions were fitted well to Langmuir isotherm. The maximum absorption of poly(3-acrylamidopropyl-trimethyl ammonium chloride (p(APTMACl)) and amid-p(AN-co-APTMACl) macro gels were 22.39 mg and 21.83 mg for As(V), and 30.65 mg and 18.16 mg for Cr(VI) ion per unit gram dried gel, respectively. Kinetically, the absorption behaviors of Cr(III) and Cr(VI) ions were fitted well to a pseudo 2nd-order kinetic model and those of As(V) ions were fitted well to a pseudo 1st order kinetic model.

  14. LCST and UCST in One: Double Thermoresponsive Behavior of Block Copolymers of Poly(ethylene glycol) and Poly(acrylamide-co-acrylonitrile).

    PubMed

    Käfer, Florian; Liu, Fangyao; Stahlschmidt, Ullrich; Jérôme, Valérie; Freitag, Ruth; Karg, Matthias; Agarwal, Seema

    2015-08-18

    The change in thermoresponsive behavior from a single phase transition of upper critical solution temperature (UCST)-type of an acrylamide-acrylonitrile copolymer (AAm-co-AN) to a double responsive behavior (LCST-UCST-type (LCST, lower critical solution temperature)) in water by the introduction of a poly(ethylene glycol) (PEG) block is highlighted in the present work. The polymer is synthesized in a simple way by free-radical polymerization of acrylamide and acrylonitrile using a poly(ethylene glycol) (PEG) macro-azoinitiator. The dual thermoresponsive behavior was observed in a wide range of concentrations repeatable for many cycles with very small hysteresis depending upon the ratio of AAm, AN and PEG. Static light scattering (SLS) and dynamic light scattering (DLS) together with turbidity photometry and transmission electron microscopy confirmed a unique phase transition behavior due to the temperature dependent change in the morphology from micelles to agglomerates. The low cytotoxicity and two-in-one thermoresponsive behavior makes the polymer promising for biomedical applications in the future. PMID:26202833

  15. Tunable quasi-cw two-micron lasing in diode-pumped crystals of mixed Tm{sup 3+}-doped sodium - lanthanum - gadolinium molybdates and tungstates

    SciTech Connect

    Bol'shchikov, F A; Ryabochkina, P A; Zharikov, Evgeny V; Lis, Denis A; Subbotin, Kirill A; Zakharov, N G; Antipov, Oleg L

    2010-12-09

    Two-micron lasing is obtained for the first time on the {sup 3}F{sub 4} {yields} {sup 3}H{sub 6} transition of Tm{sup 3+} ions in diode-pumped crystals of mixed sodium - lanthanum - gadolinium tungstate Tm:NaLa{sub 1/2}Gd{sub 1/2}(WO{sub 4}){sub 2} (C{sub Tm} = 3.6 at %) (3.6Tm : NLGW) and molybdate Tm:NaLa{sub 1/3}Gd{sub 2/3}(MoO{sub 4}){sub 2} (C{sub Tm} = 4.8 at %) (4.8Tm : NLGM). For the 3.6Tm : NLGW crystal, the quasi-cw laser output power exceeded 200 mW and the slope efficiency (with respect to absorbed pump power) for the {pi}- and {sigma}-polarisations at wavelengths of 1908 and 1918 nm was 34% and 30%, respectively. The laser wavelength of this crystal was continuously tuned within the spectral range of 1860 - 1935 nm. For the 4.8Tm : NLGM crystal, the slope efficiency for the {pi}- and {sigma}-polarisations at wavelengths of 1910 and 1918 nm was 27% and 23%, respectively, and the laser wavelength was tunable within the spectral range of 1870 - 1950 nm. (lasers)

  16. Acrylonitrile has Distinct Hormetic Effects on Acetyl-Cholinesterase Activity in Mouse Brain and Blood that are Modulated by Ethanol.

    PubMed

    Yuanqing, He; Suhua, Wang; Guangwei, Xing; Chunlan, Ren; Hai, Qian; Wenrong, Xu; Rongzhu, Lu; Aschner, Michael; Milatovic, Dejan

    2013-01-01

    Acrylonitrile(AN) is a neurotoxin both in animals and humans, but its effects on acetylcholinesterase (AChE) activity remain controversial. This study aimed to determine the dose-response effects of AN on AChE activity and the modulatory role of ethanol pre-treatment. A total of 144 Kunming mice were randomly divided into 18 groups: nine groups received 5% ethanol in their drinking water, and the remaining nine groups received regular tap water. One week later, both the ethanol and tap water only groups were given an intraperitoneal injection of AN at the following doses: 0 (control), 0.156, 0.3125, 0.625, 1.25, 2.5, 5, 10 or 20 mg AN/kg body weight. AChE activity was determined on whole blood and brain 24 h later. Blood AChE activity was higher in AN-injected mice than in controls at all doses. AChE activity in blood increased in a dose-dependent manner, peaking at 0.156 mg/kg, after which a gradual decrease ensued, displaying a β-typed dose-response relationship. In contrast, brain AChE activity, following a single AN injection, was consistently lower than in control mice, and continued to fall up to a dose of 0.313 mg/kg, and thereafter increased gradually with higher doses. Mice receiving a 20 mg/kg dose of AN exhibited AChE brain activity indistinguishable from that of control mice, demonstrating a typical U-typed dose-response relationship. The activity of AChE in the blood and brain of the AN + ethanol-treated groups displayed a shift to the right, and the magnitude of the decrease in AChE activity induced by AN was attenuated relative to the AN-only group. These results suggest that AN affects AChE activity in both mouse blood and brain in a hormetic manner. Pretreatment with ethanol modifies the effect of AN on AChE, indicating that parent AN has a more prominent role than its metabolites in modulating enzyme activity. PMID:23550232

  17. Ion-solvent and ion-ion interactions of sodium molybdate and sodium tungstate in mixtures of acetonitrile and water at 298.15, 308.15, and 318.15 K

    NASA Astrophysics Data System (ADS)

    Sarkar, B. K.; Sinha, B.; Roy, M. N.

    2008-06-01

    The apparent molar volumes ( V ϕ) and viscosity B-coefficients of sodium molybdate and sodium tungstate in aqueous binary mixtures of acetonitrile were determined from solution density and viscosity measurements at 298.15, 308.15 and 318.15 K and various electrolyte concentrations. The experimental density and viscosity data were evaluated by the Masson and Jones-Dole equations, respectively, and the parameters derived were interpreted in terms of ion-solvent and ion-ion interactions. The activation parameters of viscous flow were also determined and discussed using transition state theory.

  18. Inelastic neutron scattering studies of phonon spectra, and simulations of pressure-induced amorphization in tungstates A W O4 (A =Ba ,Sr ,Ca , and Pb )

    NASA Astrophysics Data System (ADS)

    Goel, Prabhatasree; Gupta, M. K.; Mittal, R.; Rols, S.; Achary, S. N.; Tyagi, A. K.; Chaplot, S. L.

    2015-03-01

    Lattice dynamics and high-pressure phase transitions in A W O4 (A =Ba ,Sr ,Ca , and Pb ) have been investigated using inelastic neutron scattering experiments, ab initio density functional theory calculations, and extensive molecular dynamics simulations. The vibrational modes that are internal to W O4 tetrahedra occur at the highest energies consistent with the relative stability of W O4 tetrahedra. The neutron data and the ab initio calculations are found to be in excellent agreement. The neutron and structural data are used to develop and validate an interatomic potential model. The model is used for classical molecular dynamics simulations to study their response to high pressure. We have calculated the enthalpies of the scheelite and fergusonite phases as a function of pressure, which confirms that the scheelite to fergusonite transition is second order in nature. With increase in pressure, there is a gradual change in the A O8 polyhedra, while there is no apparent change in the W O4 tetrahedra. We found that all the four tungstates amorphize at high pressure. This is in good agreement with available experimental observations which show amorphization at around 45 GPa in BaW O4 and 40 GPa in CaW O4 . Further molecular dynamics simulations at high pressure and high temperature indicate that application of pressure at higher temperature hastens the process of amorphization. On amorphization, there is an abrupt increase in the coordination of the W atom while the bisdisphenoids around the A atom are considerably distorted. The pair-correlation functions of the various atom pairs corroborate these observations. Our observations aid in predicting the pressure of amorphization in SrW O4 and PbW O4 .

  19. Acrylonitrile grafted to PVDF

    DOEpatents

    Yang, Jin; Eitouni, Hany Basam

    2015-03-31

    PVDF-g-PAN has been synthesized by grafting polyacrylonitrile onto polyvinylidene fluoride using an ATRP/AGET method. The novel polymer is ionically conducive and has much more flexibility than PVDF alone, making it especially useful either as a binder in battery cell electrodes or as a polymer electrolyte in a battery cell.

  20. Synchrotron-based FTIR microspectroscopy for the mapping of photo-oxidation and additives in acrylonitrile-butadiene-styrene model samples and historical objects.

    PubMed

    Saviello, Daniela; Pouyet, Emeline; Toniolo, Lucia; Cotte, Marine; Nevin, Austin

    2014-09-16

    Synchrotron-based Fourier transform infrared micro-spectroscopy (SR-μFTIR) was used to map photo-oxidative degradation of acrylonitrile-butadiene-styrene (ABS) and to investigate the presence and the migration of additives in historical samples from important Italian design objects. High resolution (3×3 μm(2)) molecular maps were obtained by FTIR microspectroscopy in transmission mode, using a new method for the preparation of polymer thin sections. The depth of photo-oxidation in samples was evaluated and accompanied by the formation of ketones, aldehydes, esters, and unsaturated carbonyl compounds. This study demonstrates selective surface oxidation and a probable passivation of material against further degradation. In polymer fragments from design objects made of ABS from the 1960s, UV-stabilizers were detected and mapped, and microscopic inclusions of proteinaceous material were identified and mapped for the first time.

  1. The influence of nano silica particles on gamma-irradiation ageing of elastomers based on chlorosulphonated polyethylene and acrylonitrile butadiene rubber

    NASA Astrophysics Data System (ADS)

    Marković, G.; Marinović-Cincović, M.; Tanasić, Lj.; Jovanović, V.; Samaržija-Jovanović, S.; Vukić, N.; Budinski-Simendić, J.

    2011-12-01

    The goal of this work was to study gamma irradiation ageing of rubber blends based on acrylonitrile butadiene rubber (NBR) and chlorosulphonated polyethylene rubber (CSM) reinforced by silica nano particles. The NBR/CSM compounds (50: 50, w/w) filled with different content of filler (0-100 phr) were crosslinked by sulfur. The vulcanization characteristics were assessed using the rheometer with an oscillating disk. The vulcanizates were prepared in a hydraulic press. The obtained materials were exposed to the different irradiation doses (100, 200, 300 and 400 kGy). The mechanical properties (hardness, modulus at 100% elongation, tensile strength and elongation at break) and swelling numbers were assessed before and after gamma irradiation ageing.

  2. Molecularly imprinted films of acrylonitrile/methyl methacrylate/acrylic acid terpolymers: influence of methyl methacrylate in the binding performance of L-ephedrine imprinted films.

    PubMed

    Brisbane, Carrie; McCluskey, Adam; Bowyer, Michael; Holdsworth, Clovia I

    2013-05-01

    Molecularly imprinted polymeric films (MIPFs) highly selective to 1R,2S(-)ephedrine (L-ephedrine, EPD) were produced by phase inversion post-polymerization imprinting on poly(acrylonitrile-co-methyl methacrylate-co-acrylic acid) (PAMA) terpolymers. The inclusion of methyl methacrylate (MMA) to the polymer formulation resulted in enhanced EPD selectivity which appears to be dictated by polymer composition to achieve the necessary balance between polymer rigidity and porosity. Substitution of MMA with methyl acrylate, ethyl acrylate and n-butyl acrylate resulted in a loss of EPD selectivity and EPD entrapment within the polymer matrix not observed in PAMA MIPFs. MMA, by virtue of its methyl group, is able to provide the scaffolding and rigidity necessary for stability and preservation of imprinted cavities within the PAMA MIPF leading to high EPD selectivity.

  3. Modification on liquid retention property of cassava starch by radiation grafting with acrylonitrile. I. Effect of γ-irradiation on grafting parameters

    NASA Astrophysics Data System (ADS)

    Kiatkamjornwong, S.; Chvajarernpun, J.; Nakason, C.

    1993-07-01

    Radiation modification on liquid retention properties of native cassava starch, gelatinized at 85°C, by graft copolymerization with acrylonitrile was carried out by mutual irradiation to gamma-rays. A thin aluminum foil was used to cover the inner wall of the reaction vessel, so that the homopolymer concentration was reduced to be less than 1.0% with a distilled water retention value of 665 g/g of the dry weight of the saponified grafted product. Confirmation of graft copolymerization and saponification reactions was made by the infrared spectrophotometric technique. The combined effect of radiation parameters in terms of an irradiation time and a dose rate to the total dose on the extent of the grafting reaction expressed in terms of grafting parameters which directly influenced liquid retention values was evaluated in conjunction with statistical analysis.

  4. The individual and cumulative effect of brominated flame retardant and polyvinylchloride (PVC) on thermal degradation of acrylonitrile-butadiene-styrene (ABS) copolymer.

    PubMed

    Brebu, Mihai; Bhaskar, Thallada; Murai, Kazuya; Muto, Akinori; Sakata, Yusaku; Uddin, Md Azhar

    2004-08-01

    Acrylonitrile-butadiene-styrene (ABS) copolymers without and with a polybrominated epoxy type flame retardant were thermally degraded at 450 degrees C alone (10 g) and mixed with polyvinylchloride (PVC) (8 g/2 g). Gaseous and liquid products of degradation were analysed by various gas chromatographic methods (GC with TCD, FID, AED, MSD) in order to determine the individual and cumulative effect of bromine and chlorine on the quality and quantity of degradation compounds. It was found that nitrogen, chlorine, bromine and oxygen are present as organic compounds in liquid products, their quantity depends on the pyrolysed polymer or polymer mixture. Bromophenol and dibromophenols were the main brominated compounds that come from the flame retardant. 1-Chloroethylbenzene was the main chlorine compound observed in liquid products. It was also determined that interactions appear at high temperatures during decomposition between the flame retardant, PVC and the ABS copolymer.

  5. Molecular structures of n-type semiconducting material 2,5-difluoro-1,4-phenylene-3,3‧-bis{2-[(4-trifluoromethyl)phenyl]acrylonitrile} and its photo dimerization product

    NASA Astrophysics Data System (ADS)

    Moriguchi, Tetsuji; Kitou, Naoya; Jalli, Venkataprasad; Yoza, Kenji; Nagamatsu, Shuichi; Okauchi, Tatsuo; Tsuge, Akihiko; Takashima, Wataru

    2016-08-01

    The absolute molecular structure of air stable n-type semiconducting material 2,5-difluoro-1,4-phenylene-3,3‧-bis{2-[(4-trifluoromethyl)phenyl]acrylonitrile} was determined by using twin crystal treatment X-ray diffraction analysis. The compound was readily dimerized in solution via irradiating of UV or Sun light. The exact molecular structure of the dimer also determined by X-ray analysis.

  6. A method for the quantification of biomarkers of exposure to acrylonitrile and 1,3-butadiene in human urine by column-switching liquid chromatography-tandem mass spectrometry.

    PubMed

    Schettgen, T; Musiol, A; Alt, A; Ochsmann, E; Kraus, T

    2009-02-01

    1,3-Butadiene and acrylonitrile are important industrial chemicals that have a high production volume and are ubiquitous environmental pollutants. The urinary mercapturic acids of 1,3-butadiene and acrylonitrile-N-acetyl-S-(3,4-dihydroxybutyl)cysteine (DHBMA) and MHBMA (an isomeric mixture of N-acetyl-S-((1-hydroxymethyl)-2-propenyl)cysteine and N-acetyl-S-((2-hydroxymethyl)-3-propenyl)cysteine) for the former and N-acetyl-S-2-cyanoethylcysteine (CEMA) for the latter-are specific biomarkers for the determination of individual internal exposure to these chemicals. We have developed and validated a fast, specific, and very sensitive method for the simultaneous determination of DHBMA, MHBMA, and CEMA in human urine using an automated multidimensional LC/MS/MS method that requires no additional sample preparation. Analytes are stripped from urinary matrix by online extraction on a restricted access material, transferred to the analytical column, and subsequently determined by tandem mass spectrometry using labeled internal standards. The limits of quantification (LOQs) for DHBMA, MHBMA, and CEMA were 10 microg/L, 2 microg/L, and 1 microg/L urine, respectively, and were sufficient to quantify the background exposure of the general population. Precision within series and between series for all analytes ranged from 5.4 to 9.9%; mean accuracy was between 95 and 115%. We applied the method on spot urine samples from 210 subjects from the general population with no occupational exposure to 1,3-butadiene or acrylonitrile. A background exposure of the general population to acrylonitrile was discovered that is basically influenced by individual exposure to passive smoke as well as active smoking habits. Smokers showed a significantly higher excretion of MHBMA, whereas DHBMA levels did not differ significantly. Owing to its automation, our method is well suited for application in occupational or environmental studies.

  7. Co-recycling of acrylonitrile-butadiene-styrene waste plastic and nonmetal particles from waste printed circuit boards to manufacture reproduction composites.

    PubMed

    Sun, Zhixing; Shen, Zhigang; Zhang, Xiaojing; Ma, Shulin

    2015-01-01

    This study investigated the feasibility of using acrylonitrile-butadiene-styrene (ABS) waste plastic and nonmetal particles from waste printed circuit boards (WPCB) to manufacture reproduction composites (RC), with the aim of co-recycling these two waste resources. The composites were prepared in a twin-crew extruder and investigated by means of mechanical testing, in situ flexural observation, thermogravimatric analysis, and dimensional stability evaluation. The results showed that the presence of nonmetal particles significantly improved the mechanical properties and the physical performance of the RC. A loading of 30 wt% nonmetal particles could achieve a flexural strength of 72.6 MPa, a flexural modulus of 3.57 GPa, and an impact strength of 15.5 kJ/m2. Moreover, it was found that the application of maleic anhydride-grafted ABS as compatilizer could effectively promote the interfacial adhesion between the ABS plastic and the nonmetal particles. This research provides a novel method to reuse waste ABS and WPCB nonmetals for manufacturing high value-added product, which represents a promising way for waste recycling and resolving the environmental problem.

  8. Three-dimensional Printed Acrylonitrile Butadiene Styrene Framework Coated with Cu-BTC Metal-organic Frameworks for the Removal of Methylene Blue

    NASA Astrophysics Data System (ADS)

    Wang, Zongyuan; Wang, Jiajun; Li, Minyue; Sun, Kaihang; Liu, Chang-Jun

    2014-08-01

    Three-dimensional (3D) printing was applied for the fabrication of acrylonitrile butadiene styrene (ABS) framework. Functionalization of the ABS framework was then performed by coating of porous Cu-BTC (BTC = benzene tricarboxylic acid) metal-organic frameworks on it using a step-by-step in-situ growth. The size of the Cu-BTC particles on ABS was ranged from 200 nm to 900 nm. The Cu-BTC/ABS framework can take up most of the space of the tubular reactor that makes the adsorption effective with no need of stirring. Methylene blue (MB) can be readily removed from aqueous solution by this Cu-BTC/ABS framework. The MB removal efficiency for solutions with concentrations of 10 and 5 mg/L was 93.3% and 98.3%, respectively, within 10 min. After MB adsorption, the Cu-BTC/ABS composite can easily be recovered without the need for centrifugation or filtration and the composite is reusable. In addition the ABS framework can be recovered for subsequent reuse. A significant advantage of 3D-printed frameworks is that different frameworks can be easily fabricated to meet the needs of different applications. This is a promising strategy to synthesize new frameworks using MOFs and polymers to develop materials for applications beyond adsorption.

  9. Three-dimensional printed acrylonitrile butadiene styrene framework coated with Cu-BTC metal-organic frameworks for the removal of methylene blue.

    PubMed

    Wang, Zongyuan; Wang, Jiajun; Li, Minyue; Sun, Kaihang; Liu, Chang-jun

    2014-01-01

    Three-dimensional (3D) printing was applied for the fabrication of acrylonitrile butadiene styrene (ABS) framework. Functionalization of the ABS framework was then performed by coating of porous Cu-BTC (BTC = benzene tricarboxylic acid) metal-organic frameworks on it using a step-by-step in-situ growth. The size of the Cu-BTC particles on ABS was ranged from 200 nm to 900 nm. The Cu-BTC/ABS framework can take up most of the space of the tubular reactor that makes the adsorption effective with no need of stirring. Methylene blue (MB) can be readily removed from aqueous solution by this Cu-BTC/ABS framework. The MB removal efficiency for solutions with concentrations of 10 and 5 mg/L was 93.3% and 98.3%, respectively, within 10 min. After MB adsorption, the Cu-BTC/ABS composite can easily be recovered without the need for centrifugation or filtration and the composite is reusable. In addition the ABS framework can be recovered for subsequent reuse. A significant advantage of 3D-printed frameworks is that different frameworks can be easily fabricated to meet the needs of different applications. This is a promising strategy to synthesize new frameworks using MOFs and polymers to develop materials for applications beyond adsorption. PMID:25089616

  10. Heat shrinkable behavior, physico-mechanical and structure properties of electron beam cross-linked blends of high-density polyethylene with acrylonitrile-butadiene rubber

    NASA Astrophysics Data System (ADS)

    Reinholds, Ingars; Kalkis, Valdis; Merijs-Meri, Remo; Zicans, Janis; Grigalovica, Agnese

    2016-03-01

    In this study, heat-shrinkable composites of electron beam irradiated high-density polyethylene (HDPE) composites with acrylonitrile-butadiene rubber (NBR) were investigated. HDPE/NBR blends at a ratio of components 100/0, 90/10, 80/20, 50/50 and 20/80 wt% were prepared using a two-roll mill. The compression molded films were irradiated high-energy (5 MeV) accelerated electrons up to irradiation absorbed doses of 100-300 kGy. The effect of electron beam induced cross-linking was evaluated by the changes of mechanical properties, gel content and by the differences of thermal properties, detected by differential scanning calorimetry. The thermo-shrinkage forces were determined as the kinetics of thermorelaxation and the residual shrinkage stresses of previously oriented (stretched up to 100% at above melting temperature of HDPE and followed by cooling to room temperature) specimens of irradiated HDPE/NBR blends under isometric heating-cooling mode. The compatibility between the both components was enhanced due to the formation of cross-linked sites at amorphous interphase. The results showed increase of mechanical stiffness of composites with increase of irradiation dose. The values of gel fraction compared to thermorelaxation stresses increased with the growth of irradiation dose level, as a result of formation cross-linked sites in amorphous PP/NBR interphase.

  11. Microwave absorption properties of lightweight absorber based on Fe50Ni50-coated poly(acrylonitrile) microspheres and reduced graphene oxide composites

    NASA Astrophysics Data System (ADS)

    Zhang, Bin; Wang, Jun; Wang, Junpeng; Huo, Siqi; Zhang, Bin; Tang, Yushan

    2016-09-01

    In this paper, we proposed a facile method to obtain the lightweight composites consisting of surface modified Fe50Ni50-coated poly(acrylonitrile) microspheres (PANS@SMF), reduced graphene oxide (RGO) and epoxy resin. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometry (VSM) and vector network analyzer (VNA). Impedance matching condition and electromagnetic wave attenuation characteristic were used for the reflection loss (RL) performance of the composites. Compared with pure PANS@SMF and RGO composites, the -10 dB absorption bandwidth and the minimum RL of the hybrid composites were enhanced. The bandwidth less than -10 dB was almost 4.5 GHz in the range of 10 GHz to 14.5 GHz, with a matching thickness of 2.5 mm. The density of the hybrid composites was in the range of 0.25-0.34 g/cm3. Therefore, the hybrid composite can be considered as a potential lightweight microwave absorber.

  12. Effects of aminopropyltriethoxysilane (γ-APS) on tensile properties and morphology of polypropylene (PP), recycle acrylonitrile butadiene rubber (NBRr) and sugarcane bagasse (SCB) composites

    NASA Astrophysics Data System (ADS)

    Santiagoo, Ragunathan; Omar, Latifah; Zainal, Mustaffa; Ting, Sam Sung; Ismail, Hanafi

    2015-07-01

    The performance of sugarcane baggase (SCB) treated with γ-APS filled polypropylene (PP)/recycled acrylonitrile butadiene rubber (NBRr) biocomposites were investigated. The composites with different filler loading ranging from 5 to 30 wt % were prepared using heated two roll mill by melt mixing at temperature of 180 °C. Tensile properties of the PP/NBRr/SCB composites which is tensile strength, Young Modulus and elongation at break were investigated. Increasing of treated SCB filler loading in PP/NBRr/SCB composites have increased the Young modulus however decreased the tensile strength and elongation at break of the PP/NBRr/SCB composites. From the results, γ-APS treated SCB composites shown higher tensile strength and Young Modulus but lower elongation at break when compared to the untreated SCB composites. This is due to the stronger bonding between γ-APS treated SCB with PP/NBRr matrices. These findings was supported by micrograph pictures from morphological study. SCB filler treated with γ-APS has improved the adhesion as well as gave strong interfacial bonding between SCB filler and PP/NBRr matrices which results in good tensile strength of PP/NBRr/SCB composites.

  13. A poly(acrylonitrile)-functionalized porous aromatic framework synthesized by atom-transfer radical polymerization for the extraction of uranium from seawater

    DOE PAGESBeta

    Yue, Yanfeng; Zhang, Chenxi; Tang, Qing; Mayes, Richard T.; Liao, Wei -Po; Liao, Chen; Tsouris, Costas; Stankovich, Joseph J.; Chen, Jihua; Hensley, Dale K.; et al

    2015-10-30

    In order to ensure a sustainable reserve of fuel for nuclear power generation, tremendous research efforts have been devoted to developing advanced sorbent materials for extracting uranium from seawater. In this work, a porous aromatic framework (PAF) was surface-functionalized with poly(acrylonitrile) through atom-transfer radical polymerization (ATRP). Batches of this adsorbent were conditioned with potassium hydroxide (KOH) at room temperature or 80 °C prior to contact with a uranium-spiked seawater simulant, with minimal differences in uptake observed as a function of conditioning temperature. A maximum capacity of 4.81 g-U/kg-ads was obtained following 42 days contact with uranium-spiked filtered environmental seawater, whichmore » demonstrates a comparable adsorption rate. A kinetic investigation revealed extremely rapid uranyl uptake, with more than 80% saturation reached within 14 days. Furthermore, relying on the semiordered structure of the PAF adsorbent, density functional theory (DFT) calculations reveal cooperative interactions between multiple adsorbent groups yield a strong driving force for uranium binding.« less

  14. A poly(acrylonitrile)-functionalized porous aromatic framework synthesized by atom-transfer radical polymerization for the extraction of uranium from seawater

    SciTech Connect

    Yue, Yanfeng; Zhang, Chenxi; Tang, Qing; Mayes, Richard T.; Liao, Wei -Po; Liao, Chen; Tsouris, Costas; Stankovich, Joseph J.; Chen, Jihua; Hensley, Dale K.; Abney, Carter W.; Jiang, De-en; Brown, Suree; Dai, Sheng

    2015-10-30

    In order to ensure a sustainable reserve of fuel for nuclear power generation, tremendous research efforts have been devoted to developing advanced sorbent materials for extracting uranium from seawater. In this work, a porous aromatic framework (PAF) was surface-functionalized with poly(acrylonitrile) through atom-transfer radical polymerization (ATRP). Batches of this adsorbent were conditioned with potassium hydroxide (KOH) at room temperature or 80 °C prior to contact with a uranium-spiked seawater simulant, with minimal differences in uptake observed as a function of conditioning temperature. A maximum capacity of 4.81 g-U/kg-ads was obtained following 42 days contact with uranium-spiked filtered environmental seawater, which demonstrates a comparable adsorption rate. A kinetic investigation revealed extremely rapid uranyl uptake, with more than 80% saturation reached within 14 days. Furthermore, relying on the semiordered structure of the PAF adsorbent, density functional theory (DFT) calculations reveal cooperative interactions between multiple adsorbent groups yield a strong driving force for uranium binding.

  15. Covalent immobilization of redox enzyme on electrospun nonwoven poly(acrylonitrile-co-acrylic acid) nanofiber mesh filled with carbon nanotubes: a comprehensive study.

    PubMed

    Wang, Zhen-Gang; Ke, Bei-Bei; Xu, Zhi-Kang

    2007-07-01

    In this work, novel conductive composite nanofiber mesh possessing reactive groups was electrospun from solutions containing poly(acrylonitrile-co-acrylic acid) (PANCAA) and multi-walled carbon nanotubes (MWCNTs) for redoxase immobilization, assuming that the incorporated MWCNTs could behave as electrons transferor during enzyme catalysis. The covalent immobilization of catalase from bovine liver on the neat PANCAA nanofiber mesh or the composite one was processed in the presence of EDC/NHS. Results indicated that both the amount and activity retention of bound catalase on the composite nanofiber mesh were higher than those on the neat PANCAA nanofiber mesh, and the activity increased up to 42%. Kinetic parameters, K(m) and V(max), for the catalases immobilized on the composite nanofiber mesh were lower and higher than those on the neat one, respectively. This enhanced activity might be ascribed to either promoted electron transfer through charge-transfer complexes and the pi system of carbon nanotubes or rendered biocompatibility by modified MWCNTs. Furthermore, the immobilized catalases revealed much more stability after MWCNTs were incorporated into the polymer nanofiber mesh. However, there was no significant difference in optimum pH value and temperature, thermal stability and operational stability between these two immobilized preparations, while the two ones appeared more advantageous than the free in these properties. The effect of MWCNTs incorporation on another redox enzyme, peroxidase, was also studied and it was found that the activity increased by 68% in comparison of composite one with neat preparation. PMID:17171660

  16. Zinc oxide nanorod assisted rapid single-step process for the conversion of electrospun poly(acrylonitrile) nanofibers to carbon nanofibers with a high graphitic content

    NASA Astrophysics Data System (ADS)

    Nain, Ratyakshi; Singh, Dhirendra; Jassal, Manjeet; Agrawal, Ashwini K.

    2016-02-01

    The effect of incorporation of rigid zinc oxide (ZnO) nanostructures on carbonization behavior of electrospun special acrylic fiber grade poly(acrylonitrile) (PAN-SAF) nanofibers was investigated. ZnO nanorods with high aspect ratios were incorporated into a PAN-N,N-dimethylformamide system and the composite nanofibers reinforced with aligned ZnO rods up to 50 wt% were successfully electrospun, and subsequently, carbonized. The morphology and the structural analysis of the resultant carbon nanofibers revealed that the rigid ZnO nanorods, present inside the nanofibers, possibly acted as scaffolds (temporary support structures) for immobilization of polymer chains and assisted in uniform heat distribution. This facilitated rapid and efficient conversion of the polymer structure to the ladder, and subsequently, the graphitized structure. At the end of the process, the ZnO nanorods were found to completely separate from the carbonized fibers yielding pure carbon nanofibers with a high graphitic content and surface area. The approach could be used to eliminate the slow, energy intensive stabilization step and achieve fast conversion of randomly laid carbon nanofiber webs in a single step to carbon nanofibers without the application of external tension or internal templates usually employed to achieve a high graphitic content in such systems.The effect of incorporation of rigid zinc oxide (ZnO) nanostructures on carbonization behavior of electrospun special acrylic fiber grade poly(acrylonitrile) (PAN-SAF) nanofibers was investigated. ZnO nanorods with high aspect ratios were incorporated into a PAN-N,N-dimethylformamide system and the composite nanofibers reinforced with aligned ZnO rods up to 50 wt% were successfully electrospun, and subsequently, carbonized. The morphology and the structural analysis of the resultant carbon nanofibers revealed that the rigid ZnO nanorods, present inside the nanofibers, possibly acted as scaffolds (temporary support structures) for

  17. Improvement in the etching performance of the acrylonitrile-butadiene-styrene resin by MnO2-H3PO4-H2SO4 colloid.

    PubMed

    Zhao, Wenxia; Ding, Jie; Wang, Zenglin

    2013-05-21

    The present study aimed to evaluate the surface etching of the acrylonitrile-butadiene-styrene (ABS) resin in the MnO2-H3PO4-H2SO4 colloid. To enhance the soluble Mn(IV) ion concentration and improve the etching performance of ABS resin, H3PO4 was added as a complexing agent into the MnO2-H2SO4 etching system. The effects of the H2SO4 concentration and etching time on the surface topography, surface roughness, adhesion strength, and the surface chemistry of the ABS substrates were investigated. The optimal oxidation potentials of MnO2 in the colloids decreased from 1.426 to 1.369 V with the addition of H3PO4. Though the etching conditions changed from 70 °C for 20 min to 60 °C for 10 min, the adhesion strength between the ABS substrates and electroless copper film increased from 1.19 to 1.33 KN/m after etching treatment. This could be attributed to the significant increase of the soluble Mn(IV) ion concentration in the MnO2-H3PO4-H2SO4 colloid. The surface chemistry results demonstrated that the oxidation reaction of -C═C- bonds in the polybutadiene phase was accelerated in the etching process by the addition of H3PO4, and the abundant -COOH and -OH groups were formed rapidly on the ABS surface with the etching treatment. These results were in agreement with the results of surface scanning electron microscopic observations and adhesion strength measurement. The results suggested that the MnO2-H3PO4-H2SO4 colloid was an effective surface etching system for the ABS surface roughness. PMID:23611532

  18. Copper-catalyzed retro-aldol reaction of β-hydroxy ketones or nitriles with aldehydes: chemo- and stereoselective access to (E)-enones and (E)-acrylonitriles.

    PubMed

    Zhang, Song-Lin; Deng, Zhu-Qin

    2016-07-26

    A copper-catalyzed transfer aldol type reaction of β-hydroxy ketones or nitriles with aldehydes is reported, which enables chemo- and stereoselective access to (E)-α,β-unsaturated ketones and (E)-acrylonitriles. A key step of the in situ copper(i)-promoted retro-aldol reaction of β-hydroxy ketones or nitriles is proposed to generate a reactive Cu(i) enolate or cyanomethyl intermediate, which undergoes ensuing aldol condensation with aldehydes to deliver the products. This reaction uses 1.2 mol% Cu(IPr)Cl (IPr denotes 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) as the catalyst in the presence of 6.0 mol% NaOtBu cocatalyst at room temperature or 70 °C. A range of aryl and heteroaryl aldehydes as well as acrylaldehydes are compatible with many useful functional groups being tolerated. Under the mild and weakly basic conditions, competitive Cannizzaro-type reaction of benzaldehydes and side reactions of base-sensitive functional groups can be effectively suppressed, which show synthetic advantages of this reaction compared to classic aldol reactions. The synthetic potential of this reaction is further demonstrated by the one-step synthesis of biologically active quinolines and 1,8-naphthyridine in excellent yields (up to 91%). Finally, a full catalytic cycle for this reaction has been constructed using DFT computational studies in the context of a retro-aldol/aldol two-stage mechanism. A rather flat reaction energy profile is found indicating that both stages are kinetically facile, which is consistent with the mild reaction conditions.

  19. Excited state dynamics of acrylonitrile: Substituent effects at conical intersections interrogated via time-resolved photoelectron spectroscopy and ab initio simulation

    NASA Astrophysics Data System (ADS)

    MacDonell, Ryan J.; Schalk, Oliver; Geng, Ting; Thomas, Richard D.; Feifel, Raimund; Hansson, Tony; Schuurman, Michael S.

    2016-09-01

    We report a joint experimental and theoretical study on the photoinitiated ultrafast dynamics of acrylonitrile (AN) and two methylated analogs: crotonitrile (CrN) and methacrylonitrile (MeAN). Time-resolved photoelectron spectroscopy (TRPES) and ab initio simulation are employed to discern the conical intersection mediated vibronic dynamics leading to relaxation to the ground electronic state. Each molecule is pumped with a femtosecond pulse at 200 nm and the ensuing wavepackets are probed by means of one and two photon ionization at 267 nm. The predominant vibrational motions involved in the de-excitation process, determined by ab initio trajectory simulations, are an initial twisting about the C=C axis followed by pyramidalization at a carbon atom. The decay of the time-resolved photoelectron signal for each molecule is characterized by exponential decay lifetimes for the passage back to the ground state of 60 ± 10, 86 ± 11, and 97 ± 9 fs for AN, CrN, and MeAN, respectively. As these results show, the excited state dynamics are sensitive to the choice of methylation site and the explanation for the observed trend may be found in the trajectory simulations. Specifically, since the pyramidalization motion leading to the conical intersection with the ground state is accompanied by the development of a partial negative charge at the central atom of the pyramidal group, the electron donation of the cyano group ensures that this occurs exclusively at the medial carbon atom. In this way, the donated electron density from the cyano group "directs" the wavepacket to a particular region of the intersection seam. The excellent agreement between the experimental and simulated TRPES spectra, the latter determined by employing trajectory simulations, demonstrates that this mechanistic picture is consistent with the spectroscopic results.

  20. Copper-catalyzed retro-aldol reaction of β-hydroxy ketones or nitriles with aldehydes: chemo- and stereoselective access to (E)-enones and (E)-acrylonitriles.

    PubMed

    Zhang, Song-Lin; Deng, Zhu-Qin

    2016-07-26

    A copper-catalyzed transfer aldol type reaction of β-hydroxy ketones or nitriles with aldehydes is reported, which enables chemo- and stereoselective access to (E)-α,β-unsaturated ketones and (E)-acrylonitriles. A key step of the in situ copper(i)-promoted retro-aldol reaction of β-hydroxy ketones or nitriles is proposed to generate a reactive Cu(i) enolate or cyanomethyl intermediate, which undergoes ensuing aldol condensation with aldehydes to deliver the products. This reaction uses 1.2 mol% Cu(IPr)Cl (IPr denotes 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) as the catalyst in the presence of 6.0 mol% NaOtBu cocatalyst at room temperature or 70 °C. A range of aryl and heteroaryl aldehydes as well as acrylaldehydes are compatible with many useful functional groups being tolerated. Under the mild and weakly basic conditions, competitive Cannizzaro-type reaction of benzaldehydes and side reactions of base-sensitive functional groups can be effectively suppressed, which show synthetic advantages of this reaction compared to classic aldol reactions. The synthetic potential of this reaction is further demonstrated by the one-step synthesis of biologically active quinolines and 1,8-naphthyridine in excellent yields (up to 91%). Finally, a full catalytic cycle for this reaction has been constructed using DFT computational studies in the context of a retro-aldol/aldol two-stage mechanism. A rather flat reaction energy profile is found indicating that both stages are kinetically facile, which is consistent with the mild reaction conditions. PMID:27397647

  1. Laser transmission welding of Acrylonitrile-Butadiene-Styrene (ABS) using a tailored high power diode-laser optical fiber coupled system

    NASA Astrophysics Data System (ADS)

    Rodríguez-Vidal, E.; Quintana, I.; Etxarri, J.; Otaduy, D.; González, F.; Moreno, F.

    2012-06-01

    Laser transmission welding (LTW) of polymers is a direct bonding technique which is already used in different industrial applications sectors such as automobile, microfluidic, electronic and biomedicine. This technique offers several advantages over conventional methods, especially when a local deposition of energy and minimum thermal distortions are required. In LTW one of the polymeric materials needs to be transparent to the laser wavelength and the second part needs to be designed to be absorbed in IR spectrum. This report presents a study of laser weldability of ABS (acrylonitrile/butadiene/styrene) filled with two different concentrations of carbon nanotubes (0.01% and 0.05% CNTs). These additives are used as infrared absorbing components in the laser welding process, affecting the thermal and optical properties of the material and, hence, the final quality of the weld seam. A tailored laser system has been designed to obtain high quality weld seams with widths between 0.4 and 1.0mm. It consists of two diode laser bars (50W per bar) coupled into an optical fiber using a non-imaging solution: equalization of the beam quality factor (M2) in the slow and fast axes by a pair of micro step-mirrors. The beam quality factor has been analyzed at different laser powers with the aim to guarantee a coupling efficiency to the multimode optical fiber. The power scaling is carried out by means of multiplexing polarization technique. The analysis of energy balance and beam quality is performed in two linked steps: first by means ray tracing simulations (ZEMAX®) and second, by validation. Quality of the weld seams is analyzed in terms of the process parameters (welding speed, laser power and clamping pressure) by visual and optical microscope inspections. The optimum laser power range for three different welding speeds is determinate meanwhile the clamping pressure is held constant. Additionally, the corresponding mechanical shear tests were carried out to analyze the

  2. Comparative metabolism of methacrylonitrile and acrylonitrile to cyanide using cytochrome P4502E1 and microsomal epoxide hydrolase-null mice

    SciTech Connect

    El Hadri, L.; Chanas, B.; Ghanayem, B.I. . E-mail: ghanayem@niehs.nih.gov

    2005-06-01

    Methacrylonitrile (MAN) and acrylonitrile (AN) are metabolized via glutathione (GSH) conjugation or epoxide formation. We have recently shown that CYP2E1 is essential for AN epoxidation and subsequent cyanide liberation. Current studies were designed to compare the enzymatic basis of MAN vs. AN metabolism to cyanide using wild-type (WT), CYP2E1-, and mEH-null mice. Mice received a single gavage dose of 0.047, 0.095, 0.19, or 0.38 mmol/kg of MAN or AN, and blood cyanide was measured at 1 or 3 h later. Blood cyanide levels in WT mice treated with AN or MAN were dose and time dependent. At equimolar doses, significantly higher levels of cyanide were detected in the blood of MAN- vs. AN-treated mice. Further, while significant reduction in blood cyanide levels occurred in MAN-treated CYP2E1-null vs. WT mice, AN metabolism to cyanide was largely abolished in CYP2E1-null mice. Pretreatment of mice with 1-aminobenzotriazole (ABT, CYP inhibitor) demonstrated that CYPs other than CYP2E1 also contribute to MAN metabolism to cyanide. Blood cyanide levels in mEH-null mice treated with aliphatic nitriles are generally lower than levels in similarly treated WT mice. Western blot analysis showed that expression of sEH was greater in male vs. female mice. The role of various epoxide hydrolases (EHs) in the production of cyanide from aliphatic nitriles is apparently structure and dose dependent. Regardless of genotype, significantly higher levels of cyanide were measured in the blood of male vs. female mice treated with MAN or AN. In conclusion, these data showed that (1) at equimolar doses, higher blood cyanide levels were detected in mice treated with MAN vs. AN; (2) while CYP2E1 is the only enzyme responsible for AN metabolism to cyanide, other CYPs also contribute to MAN metabolism; and (3) significantly higher levels of cyanide were measured in the blood of male vs. female treated with either nitrile. Higher blood cyanide levels in male vs. female mice and in MAN- vs. AN

  3. Local Structure of Proton-Conducting Lanthanum Tungstate La28-xW4+xO54+δ: a Combined Density Functional Theory and Pair Distribution Function Study

    SciTech Connect

    Kalland, Liv-Elisif; Magrasó, Anna; Mancini, Alessandro; Tealdi, Cristina; Malavasi, Lorenzo

    2013-10-02

    Lanthanum tungstate (La28–xW4+xO54+δ) is a good proton conductor and exhibits a complex fluorite-type structure. To gain further understanding of the short-range order in the structure we correlate the optimized configurations obtained by density functional theory (DFT) with the experimental atomic pair distribution function analysis (PDF) of time-of-flight neutron and synchrotron X-ray data, collected at room temperature. The local atomic arrangements cannot be described by means of any average symmetric structure. Tungsten forms WO6 octahedra in alternating directions, La1 is mainly 8-fold coordinated in relatively symmetric cubes, and La2 is coordinated with 6 or 7 oxygens in heavily distorted cubes. Both DFT and PDF confirm that the excess tungsten (x) is incorporated in La2 (1/4, 1/4, 1/4) sites in the La27W5O55.5 composition. This additional tungsten can be considered as a donor self-dopant in the material and has implications to the conducting properties and the defect structure.

  4. Effect of Mixed Glass Former on Ionic Conductivity of Silver Boro Tungstate glass system x[0.75AgI:0.25AgCl]: (1-x) [Ag2O-{B2O3:WO3}

    NASA Astrophysics Data System (ADS)

    Dehariya, Harsha; Kumar, R.; Polu, A. R.

    2012-05-01

    The idea to explore new 'Superionic Electrolytes', "Fast ionic conductors" is due to their tremendous potential applications in solid state electrochemical devices viz. solid state batteries, fuel cells, sensors, super capacitors. Superionic glasses have attracted great deal of attention due to their several advantageous over their crystalline counterparts such as high ionic conductivity, easy preparation, wide selection of compositions, isotropic properties and high stability etc [4-7]. Large numbers of silver ion based glasses have been reported in the literature for the glassy system of AgI:Ag2O: MxOy (MxOy = B2O3, SiO2, P2O5, GeO2, V2O5, As2O5, CrO3, SeO2, MoO3 & TeO3 etc many of them shows high silver ion conductivity [8]. Ion transport behavior of Silver Boro Tungstate glass system x[0.75AgI:0.25AgCl]: (1-x) [Ag2O{B2O3:WO3}], where 0 <= x <= 1 in molar wt% prepared by melt quench technique were reported. The new host [0.75AgI:0.25AgCl] was used as a better alternate in place of conventional host salt AgI. Conductivity measurement were carried out on this glass system as a function of frequency from 50 Hz to 5 MHz, over a temperature range of 27°C to 200°C, for different compositions by Impedance spectroscopy. The composition 0.7[0.75AgI:0.25AgCl]: 0.3[Ag2O{B2O3:WO3}] shows the highest conductivity of the order of σrt ~ 2.76 × 10-2 S/cm, referred to as the Optimum Conducting Composition (OCC). The enhancement in the conductivity has been obtained by mixed former effect. XRD result shows that the system is completely amorphous. Temperature dependence of conductivity of all compositions were studied & reported. Activation energies (Ea) were also evaluated from the slope of .Log(σ) vs 1000/T, Arrhenius plots.

  5. Poly(methyl methacrylate-acrylonitrile-ethyl acrylate) terpolymer based gel electrolyte for LiNi0.5Mn1.5O4 cathode of high voltage lithium ion battery

    NASA Astrophysics Data System (ADS)

    Sun, Ping; Liao, Youhao; Xie, Huili; Chen, Tingting; Rao, Mumin; Li, Weishan

    2014-12-01

    A novel gel polymer electrolyte (GPE), based on poly(methyl methacrylate-acrylonitrile-ethyl acrylate) (P(MMA-AN-EA)) terpolymer, is designed to match LiNi0.5Mn1.5O4 cathode of 5 V lithium ion battery. The performances of the synthesized P(MMA-AN-EA) terpolymer and the corresponding membrane and GPE are investigated by scanning electron microscope, energy dispersive spectroscopy, nuclear magnetic resonance spectra, Fourier transform infrared spectra, thermogravimetric analyzer, electrochemical impedance spectroscopy, linear sweep voltammetry, and charge/discharge test. It is found that the pore structure of P(MMA-AN-EA) membrane is affected by the dose of pore forming agent, polyethylene glycol (PEG400). The membrane with 3 wt% PEG400 presents the best pore structure, in which pores are dispersed uniformly and interconnected, and exhibits the largest electrolyte uptake, resulting in the highest ionic conductivity of 3.82 × 10-3 S cm-1 for the corresponding GPE at room temperature. The GPE has improved compatibility with lithium anode and is electrochemically stable up to 5.2 V (vs. Li/Li+). The high voltage LiNi0.5Mn1.5O4 cathode using the resulting GPE exhibits excellent cyclic stability, maintaining 97.9% of its initial discharge capacity after 100 cycles compared to that of 79.7% for the liquid electrolyte at 0.5 C.

  6. Preparation and Characterization of Facilitated Transport Membranes Composed of Chitosan-Styrene and Chitosan-Acrylonitrile Copolymers Modified by Methylimidazolium Based Ionic Liquids for CO₂ Separation from CH₄ and N₂.

    PubMed

    Otvagina, Ksenia V; Mochalova, Alla E; Sazanova, Tatyana S; Petukhov, Anton N; Moskvichev, Alexandr A; Vorotyntsev, Andrey V; Afonso, Carlos A M; Vorotyntsev, Ilya V

    2016-06-09

    CO₂ separation was found to be facilitated by transport membranes based on novel chitosan (CS)-poly(styrene) (PS) and chitosan (CS)-poly(acrylonitrile) (PAN) copolymer matrices doped with methylimidazolium based ionic liquids: [bmim][BF₄], [bmim][PF₆], and [bmim][Tf₂N] (IL). CS plays the role of biodegradable film former and selectivity promoter. Copolymers were prepared implementing the latest achievements in radical copolymerization with chosen monomers, which enabled the achievement of outstanding mechanical strength values for the CS-based membranes (75-104 MPa for CS-PAN and 69-75 MPa for CS-PS). Ionic liquid (IL) doping affected the surface and mechanical properties of the membranes as well as the gas separation properties. The highest CO₂ permeability 400 Barrers belongs to CS-b-PS/[bmim][BF₄]. The highest selectivity α (CO₂/N₂) = 15.5 was achieved for CS-b-PAN/[bmim][BF₄]. The operational temperature of the membranes is under 220 °C.

  7. Important role of molecular packing and intermolecular interactions in two polymorphs of (Z)-2-phenyl-3-(4-(pyridin-2-yl)phenyl)acrylonitrile. Preparation, structures, and optical properties

    NASA Astrophysics Data System (ADS)

    Percino, M. Judith; Cerón, Margarita; Ceballos, Paulina; Soriano-Moro, Guillermo; Castro, M. Eugenia; Chapela, Víctor M.; Bonilla-Cruz, José; Reyes-Reyes, Marisol; López-Sandoval, Román; Siegler, Maxime A.

    2014-12-01

    The novel compound Z-2-phenyl-3-(4-(pyridin-2-yl)phenyl)acrylonitrile (PPyPAN) was synthesized from the condensation reaction between phenylacetonitrile and 4-(pyridin-2-yl)benzaldehyde. This compound crystallizes in two forms: polymorph I (triclinic, P - 1, Z‧ = 2) and polymorph II (orthorhombic, Pbc21, Z‧ = 2). The molecular structures and optical properties of the two polymorphs have been characterized via1H NMR, EI, FTIR, UV-Vis spectroscopy, DSC, single-crystal and XRPD. The molecular structure, packing properties, and intermolecular interactions were examined for both polymorphs of PPyPAN in order to interpret the emission properties. A subtle change in the molecular conformation (e.g., a rotation around single Csbnd C bonds) found for both polymorph plays an important role in their solid-state properties. The structure and optical properties of the new structures were well characterized and showed unique features for both polymorphic phases. For phase I, we observed an excitation spectrum with an λex at 325-346 nm, which is the maximum excitation or absorption wavelength for the lowest So → S1 transition, which is characteristic to the π-π* transition, and an emission spectrum with an λemmax at 454 nm. For phase II, the excitation spectrum showed an λexmax at 325 nm, whereas the λemmax showed a red-shift to 492 nm.

  8. Preparation and Characterization of Facilitated Transport Membranes Composed of Chitosan-Styrene and Chitosan-Acrylonitrile Copolymers Modified by Methylimidazolium Based Ionic Liquids for CO2 Separation from CH4 and N2

    PubMed Central

    Otvagina, Ksenia V.; Mochalova, Alla E.; Sazanova, Tatyana S.; Petukhov, Anton N.; Moskvichev, Alexandr A.; Vorotyntsev, Andrey V.; Afonso, Carlos A. M.; Vorotyntsev, Ilya V.

    2016-01-01

    CO2 separation was found to be facilitated by transport membranes based on novel chitosan (CS)–poly(styrene) (PS) and chitosan (CS)–poly(acrylonitrile) (PAN) copolymer matrices doped with methylimidazolium based ionic liquids: [bmim][BF4], [bmim][PF6], and [bmim][Tf2N] (IL). CS plays the role of biodegradable film former and selectivity promoter. Copolymers were prepared implementing the latest achievements in radical copolymerization with chosen monomers, which enabled the achievement of outstanding mechanical strength values for the CS-based membranes (75–104 MPa for CS-PAN and 69–75 MPa for CS-PS). Ionic liquid (IL) doping affected the surface and mechanical properties of the membranes as well as the gas separation properties. The highest CO2 permeability 400 Barrers belongs to CS-b-PS/[bmim][BF4]. The highest selectivity α (CO2/N2) = 15.5 was achieved for CS-b-PAN/[bmim][BF4]. The operational temperature of the membranes is under 220 °C. PMID:27294964

  9. Morphology, mechanical, cross-linking, thermal, and tribological properties of nitrile and hydrogenated nitrile rubber/multi-walled carbon nanotubes composites prepared by melt compounding: The effect of acrylonitrile content and hydrogenation

    NASA Astrophysics Data System (ADS)

    Likozar, Blaž; Major, Zoltan

    2010-11-01

    The purpose of this work was to prepare nanocomposites by mixing multi-walled carbon nanotubes (MWCNT) with nitrile and hydrogenated nitrile elastomers (NBR and HNBR). Utilization of transmission electronic microscopy (TEM), scanning electron microscopy (SEM), and small- and wide-angle X-ray scattering techniques (SAXS and WAXS) for advanced morphology observation of conducting filler-reinforced nitrile and hydrogenated nitrile rubber composites is reported. Principal results were increases in hardness (maximally 97 Shore, type A), elastic modulus (maximally 981 MPa), tensile strength (maximally 27.7 MPa), elongation at break (maximally 216%), cross-link density (maximally 7.94 × 1028 m-3), density (maximally 1.16 g cm-3), and tear strength (11.2 kN m-1), which were clearly visible at particular acrylonitrile contents both for unhydrogenated and hydrogenated polymers due to enhanced distribution of carbon nanotubes (CNT) and their aggregated particles in the applied rubber matrix. Conclusion was that multi-walled carbon nanotubes improved the performance of nitrile and hydrogenated nitrile rubber nanocomposites prepared by melt compounding.

  10. Scandium tungstate above 2.5 GPa

    NASA Astrophysics Data System (ADS)

    Cetinkol, Mehmet; Wilkinson, Angus P.; Chapman, Karena W.

    2008-12-01

    Synchrotron x-ray powder diffraction was used to study Sc 2W 3O 12 in a diamond anvil cell up to 6.2 GPa in order to better characterize the second high pressure phase observed in earlier in-situ diffraction studies. Two crystalline-to-crystalline phase transitions were observed, in line with the earlier work. Above 2.7 GPa, Sc 2W 3O 12 adopted a monoclinic structure with probable space group P2 1/n, that is distinct from the monoclinic phase existing between 0.3 GPa and 2.7 GPa. The bulk modulous (K0) for this second high pressure phase was estimated to be 90(3) GPa using a Birch-Murnaghan equation of state with Kp fixed at 4. Refining Kp resulted in K0=72(3) GPa and Kp=12(1). The transition at ˜2.7 GPa on compression involved a unit cell volume reduction of almost 18% and was not reversible on decompression to atmospheric pressure at ambient temperature, suggesting that changes in bonding occur at the phase transition. Linear compressibility values for this high pressure monoclinic phase were estimated to be βa=3.6(1)×10-3 GPa, βb=3.7(2)×10-3 GPa, βc=2.0(1)×10-3 GPa by straight line fits to the lattice constants over the range 0-6.2 GPa.

  11. Stability improvement of gel-state dye-sensitized solar cells by utilization the co-solvent effect of propionitrile/acetonitrile and 3-methoxypropionitrile/acetonitrile with poly(acrylonitrile-co-vinyl acetate)

    NASA Astrophysics Data System (ADS)

    Venkatesan, Shanmugam; Su, Song-Chuan; Kao, Shon-Chen; Teng, Hsisheng; Lee, Yuh-Lang

    2015-01-01

    Propionitrile (PPN) or 3-methoxypropionitrile (MPN) is mixed with acetonitrile (ACN) to prepare ACN/PPN and ACN/MPN co-solvents and used to fabricate polymer gel electrolytes (PGEs) of dye-sensitized solar cells (DSSCs), aiming at improving the stability of gel-state DSSCs. Co-solvents with various ratios are utilized to prepare PGEs using poly(acrylonitrile-co-vinyl acetate) (PAN-VA) as the gelator. The ratio effects of the co-solvents on the properties of PGEs and the performances of the corresponding DSSCs are studied. The results show that in-situ gelation of the gel-electrolytes can still be performed at the presence of 40% PPN or 30% MPN. However, increasing the composition of PPN and MPN in the co-solvents triggers a decrease in the diffusivity and conductivity of the PGEs, but an increase in the viscosity. Therefore, the energy conversion efficiencies of the cells decrease as a result. However, the introduction of PPN and MPN elevates the gel-to-liquid transition temperature (Tp) of the PGEs which significantly increases the stability of the gel-state DSSCs. Comparing between the effects of the two co-solvents, PPN and MPN have similar effect on elevation of Tp, but the conductivity of PGEs and the corresponding cell efficiency are higher for the ACN/PPN system, attributed to its lower viscosity compared with ACN/MPN system. By using the ACN/PPN (60/40) co-solvent at the presence of TiO2 fillers, gel-state cell with an efficiency of 8.3% can be achieved, which is even higher than that obtained by the liquid state cell (8%). After 500 h test at 60 °C, the cell can retain 95.4% of its initial efficiency.

  12. Performance improvement of gel- and solid-state dye-sensitized solar cells by utilization the blending effect of poly (vinylidene fluoride-co-hexafluropropylene) and poly (acrylonitrile-co-vinyl acetate) co-polymers

    NASA Astrophysics Data System (ADS)

    Venkatesan, Shanmugam; Obadja, Nesia; Chang, Ting-Wei; Chen, Li-Tung; Lee, Yuh-Lang

    2014-12-01

    Poly (vinylidene fluoride-co-hexafluropropylene) (PVDF-HFP) and poly (acrylonitrile-co-vinyl acetate) (PAN-VA) are used as gelator to prepare gel- and solid-state polymer electrolytes for dye sensitized solar cells (DSSCs) applications. The electrolytes prepared using PVDF-HFP have higher conductivities than those prepared using PAN-VA. In blended polymers, the conductivities of the electrolytes increase with increasing composition of PVDF-HFP; at 75% PVDF-HFP, conductivity of the blended polymer surpassed that of pure polymers. It is also found that the viscosity of the electrolyte prepared by PAN-VA (1.2 kPaS) is much lower than that by PVDF-HFP (11 kPaS). Therefore, increasing PAN-VA composition can decrease the viscosity of the electrolyte, improving the penetration of electrolytes in the TiO2 matrix. By controlling the ratio of PVDF-HFP/PAN-VA, the conductivity and viscosity of the electrolyte can be regulated and an optimal ratio based on the conversion efficiency of the gel- and solid state DSSCs is obtained at the ratio of 3/1. The highest efficiency achieved by the gel- and solid-state cells using the blending polymers are 6.3% and 4.88%, respectively, which are higher than those prepared using pure polymers (5.53% and 4.56%, respectively). The introduction of TiO2 fillers to the solid electrolyte can further increase the cell efficiency to 5.34%.

  13. Comparison of sodium naphthenate and air-ionization corona discharge as surface treatments for the ethylene-tetrafluoroethylene polymer (ETFE) to improve adhesion between ETFE and acrylonitrile-butadiene-styrene polymer (ABS) in the presence of a cyanoacrylate adhesive (CAA)

    NASA Astrophysics Data System (ADS)

    Lucía Johanning-Solís, Ana; Stradi-Granados, Benito A.

    2014-09-01

    This study compares two ethylene-tetrafluoroethylene (ETFE) surface activation treatments, namely chemical attack with a solution of sodium naphthenate and plasma erosion via air-ionization corona discharge in order to improve the adhesive properties of the ETFE. An experimental design was prepared for both treatments in order to assess the effect of the treatment characteristics on the tensile load needed to break the bond between the ETFE and the acrylonitrile-butadiene-styrene polymer (ABS) formed with a cyanoacrylate adhesive (CAA) applied between them. The reason for the selection of this problem is that both polymers are frequently used in the biomedical industry for their properties, and they need to be joined firmly in biomedical devices, and the cyanoacrylate adhesive is the adhesive traditionally used for fluoropolymers, in this case the ETFE, and the same CAA has also shown good adhesion with ABS. However, the strength of the bond for the triplet ETFE-CAA-ABS has not been reported and the improvement of the strength of the bond with surface treatments is not found in scholarly journals for modern medical devices such as stents and snares. Both treatments were compared based on the aforementioned design of experiments. The case where ETFE receives no surface treatment serves as the reference. The results indicated that the three factors evaluated (initial drying of the material, temperature of the chemical bath, and immersion time), and their interactions have no significant effect over the tensile load at failure (tensile strength) of the adhesive bond being evaluated. For the air-ionization corona discharge treatment, two factors were evaluated: discharge exposition time and air pressure. The results obtained from this experimental design indicate that there is no significant difference between the levels of the factors evaluated. These results were unexpected as the ranges used were representative of the maximum ranges permissible in manufacturing

  14. 21 CFR 180.22 - Acrylonitrile copolymers.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... equilibrium at 120 °F with food-simulating solvents appropriate to the intended conditions of use. (2) In the... container when extracted to equilibrium at 120 °F with food-simulating solvents appropriate to the intended... quantitative migration values at the time of equilibrium extractions, utilizing solvents and...

  15. 21 CFR 180.22 - Acrylonitrile copolymers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... equilibrium at 120 °F with food-simulating solvents appropriate to the intended conditions of use. (2) In the... container when extracted to equilibrium at 120 °F with food-simulating solvents appropriate to the intended... quantitative migration values at the time of equilibrium extractions, utilizing solvents and...

  16. 21 CFR 180.22 - Acrylonitrile copolymers.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... equilibrium at 120 °F with food-simulating solvents appropriate to the intended conditions of use. (2) In the... container when extracted to equilibrium at 120 °F with food-simulating solvents appropriate to the intended... quantitative migration values at the time of equilibrium extractions, utilizing solvents and...

  17. 21 CFR 180.22 - Acrylonitrile copolymers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...—0.003 milligram/square inch when extracted to equilibrium at 120 °F with food-simulating solvents... calculated on the basis of the volume of the container when extracted to equilibrium at 120 °F with food... use. (2) Qualitative and quantitative migration values at the time of equilibrium...

  18. 21 CFR 180.22 - Acrylonitrile copolymers.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... equilibrium at 120 °F with food-simulating solvents appropriate to the intended conditions of use. (2) In the... container when extracted to equilibrium at 120 °F with food-simulating solvents appropriate to the intended... quantitative migration values at the time of equilibrium extractions, utilizing solvents and...

  19. 29 CFR 1910.1045 - Acrylonitrile.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... provide to employees, the appropriate respirators specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134. (ii) For escape, provide employees with any organic vapor respirator or any self-contained breathing...) of this section, the facilities required by 29 CFR 1910.141, including clean change rooms and...

  20. 29 CFR 1910.1045 - Acrylonitrile.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... provide to employees, the appropriate respirators specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134. (ii) For escape, provide employees with any organic vapor respirator or any self-contained breathing...) of this section, the facilities required by 29 CFR 1910.141, including clean change rooms and...

  1. 29 CFR 1910.1045 - Acrylonitrile.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... provide to employees, the appropriate respirators specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134. (ii) For escape, provide employees with any organic vapor respirator or any self-contained breathing...) of this section, the facilities required by 29 CFR 1910.141, including clean change rooms and...

  2. 29 CFR 1910.1045 - Acrylonitrile.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... provide to employees, the appropriate respirators specified in paragraph (d)(3)(i)(A) of 29 CFR 1910.134. (ii) For escape, provide employees with any organic vapor respirator or any self-contained breathing...) of this section, the facilities required by 29 CFR 1910.141, including clean change rooms and...

  3. 29 CFR 1910.1045 - Acrylonitrile.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... per million parts of air (2 ppm) as an eight (8)-hour time-weighted average. (ii) Ceiling limit. The... shall be made from air samples that are representative of each employee's exposure to AN over an eight... covers each employee required by this section to use a respirator. (ii) If air-purifying...

  4. Catalyst for propylene ammoxidation to acrylonitrile

    SciTech Connect

    Paparizos, C.; Shaw, W.G.

    1992-07-28

    This patent describes a catalyst composition. It comprises: a complex of the catalytic oxides of molybdenum, bismuth, iron, cobalt, nickel, chromium, one or more of phosphorus and antimony, one or more of the group comprising alkali metals, and optionally one or more of an alkaline earth metal, a rare earth metal, niobium, thallium, arsenic, magnesium, zinc, cadmium, vanadium, boron, calcium, tin, germanium, manganese, tungsten, and/or tellurium having he formula: Mo[sub a]Bi[sub b]Fe[sub c]Co[sub d]Ni[sub e]Cr[sub f]X[sub g]Z[sub j]O[sub x].

  5. Synthesis of Compositionally Defined Single-Crystalline Eu 3+ -Activated Molybdate–Tungstate Solid-Solution Composite Nanowires and Observation of Charge Transfer in a Novel Class of 1D CaMoO 4 –CaWO 4 :Eu 3+ –0D CdS/CdSe QD Nanoscale Heterostructures

    DOE PAGESBeta

    Han, Jinkyu; McBean, Coray; Wang, Lei; Jaye, Cherno; Liu, Haiqing; Fischer, Daniel A.; Wong, Stanislaus S.

    2015-02-10

    As a first step, we have synthesized and optically characterized a systematic series of one-dimensional (1D) single-crystalline Eu³⁺-activated alkaline-earth metal tungstate/molybdate solid solution composite CaW₁₋xMoxO₄ (0 ≤ ‘x’ ≤ 1) nanowires of controllable chemical composition using a modified template-directed methodology under ambient room-temperature conditions. Extensive characterization of the resulting nanowires has been performed using X-ray diffraction, electron microscopy, and optical spectroscopy. The crystallite size and single crystallinity of as-prepared 1D CaW₁₋xMoxO₄: Eu³⁺ (0 ≤ ‘x’ ≤ 1) solid solution composite nanowires increase with increasing Mo component (‘x’). We note a clear dependence of luminescence output upon nanowire chemical composition withmore » our 1D CaW₁₋xMoxO₄: Eu³⁺ (0 ≤ ‘x’ ≤ 1) evincing the highest photoluminescence (PL) output at ‘x’ = 0.8, amongst samples tested. Subsequently, coupled with either zero-dimensional (0D) CdS or CdSe quantum dots (QDs), we successfully synthesized and observed charge transfer processes in 1D CaW1-xMoxO4: Eu3+ (‘x’ = 0.8) – 0D QD composite nanoscale heterostructures. Our results show that CaW₁₋xMoxO₄: Eu³⁺ (‘x’ = 0.8) nanowires give rise to PL quenching when CdSe QDs and CdS QDs are anchored onto the surfaces of 1D CaW₁₋xMoxO₄: Eu³⁺ nanowires. The observed PL quenching is especially pronounced in CaW₁₋xMoxO₄: Eu³⁺ (‘x’ = 0.8) – 0D CdSe QD heterostructures. Conversely, the PL output and lifetimes of CdSe and CdS QDs within these heterostructures are not noticeably altered as compared with unbound CdSe and CdS QDs. The difference in optical behavior between 1D Eu³⁺ activated tungstate and molybdate solid solution nanowires and the semiconducting 0D QDs within our heterostructures can be correlated with the relative positions of their conduction and valence energy band levels. We propose that

  6. Synthesis of Compositionally Defined Single-Crystalline Eu 3+ -Activated Molybdate–Tungstate Solid-Solution Composite Nanowires and Observation of Charge Transfer in a Novel Class of 1D CaMoO 4 –CaWO 4 :Eu 3+ –0D CdS/CdSe QD Nanoscale Heterostructures

    SciTech Connect

    Han, Jinkyu; McBean, Coray; Wang, Lei; Jaye, Cherno; Liu, Haiqing; Fischer, Daniel A.; Wong, Stanislaus S.

    2015-02-10

    As a first step, we have synthesized and optically characterized a systematic series of one-dimensional (1D) single-crystalline Eu³⁺-activated alkaline-earth metal tungstate/molybdate solid solution composite CaW₁₋xMoxO₄ (0 ≤ ‘x’ ≤ 1) nanowires of controllable chemical composition using a modified template-directed methodology under ambient room-temperature conditions. Extensive characterization of the resulting nanowires has been performed using X-ray diffraction, electron microscopy, and optical spectroscopy. The crystallite size and single crystallinity of as-prepared 1D CaW₁₋xMoxO₄: Eu³⁺ (0 ≤ ‘x’ ≤ 1) solid solution composite nanowires increase with increasing Mo component (‘x’). We note a clear dependence of luminescence output upon nanowire chemical composition with our 1D CaW₁₋xMoxO₄: Eu³⁺ (0 ≤ ‘x’ ≤ 1) evincing the highest photoluminescence (PL) output at ‘x’ = 0.8, amongst samples tested. Subsequently, coupled with either zero-dimensional (0D) CdS or CdSe quantum dots (QDs), we successfully synthesized and observed charge transfer processes in 1D CaW1-xMoxO4: Eu3+ (‘x’ = 0.8) – 0D QD composite nanoscale heterostructures. Our results show that CaW₁₋xMoxO₄: Eu³⁺ (‘x’ = 0.8) nanowires give rise to PL quenching when CdSe QDs and CdS QDs are anchored onto the surfaces of 1D CaW₁₋xMoxO₄: Eu³⁺ nanowires. The observed PL quenching is especially pronounced in CaW₁₋xMoxO₄: Eu³⁺ (‘x’ = 0.8) – 0D CdSe QD heterostructures. Conversely, the PL output and lifetimes of CdSe and CdS QDs within these heterostructures are not noticeably altered as compared with unbound CdSe and CdS QDs. The difference in optical behavior between 1D Eu³⁺ activated tungstate and molybdate solid solution nanowires and the semiconducting 0D QDs within our

  7. Buffing dust as a filler of carboxylated butadiene-acrylonitrile rubber and butadiene-acrylonitrile rubber.

    PubMed

    Chronska, K; Przepiorkowska, A

    2008-03-01

    Buffing dust from chrome tanned leather is one of the difficult tannery wastes to manage. It is also hazardous to both human health and the environment. The scientific literature rarely reports studies on dust management, especially on its utilization as a filler for elastomers. In this connection we have made an attempt to use this leather waste as a filler for rubbers such as XNBR and NBR. The addition of the buffing dust to rubber mixes brought improvement in mechanical properties, and increase in resistance to thermal ageing as well as in electric conductivity and crosslink density of vulcalizates. PMID:17629616

  8. Synthesis, characterization, and properties of reduced europium molybdates and tungstates

    SciTech Connect

    Abeysinghe, Dileka; Gerke, Birgit; Morrison, Gregory; Hsieh, Chun H.; Smith, Mark D.; Pöttgen, Rainer; Makris, Thomas M.; Loye, Hans-Conrad zur

    2015-09-15

    Single crystals of K{sub 0.094}Eu{sub 0.906}MoO{sub 4}, K{sub 0.097}Eu{sub 0.903}WO{sub 4}, EuWO{sub 4}, and EuMoO{sub 4} were grown from molten chloride fluxes contained in vacuum-sealed fused silica and structurally characterized via single crystal X-ray diffraction. The in situ reduction of Eu{sup 3+} to Eu{sup 2+} was carried out using Mo, W, and Zn as metal reducing agents. All four compounds crystallize in the tetragonal space group of I4{sub 1}/a and adopt the scheelite (CaWO{sub 4}) structure type. The magnetic susceptibility of the reported compounds shows paramagnetic behavior down to 2 K. {sup 151}Eu Mössbauer spectroscopy was used to analyze the relative Eu{sup 2+} and Eu{sup 3+} content of the samples. All the compounds were further characterized by EPR, and UV-vis spectroscopy. - Graphical abstract: TOC Caption Two new reduced europium containing quaternary oxides, K{sub 0.094}Eu{sub 0.906}MoO{sub 4} and K{sub 0.097}Eu{sub 0.903}WO{sub 4}, and two previously reported ternary reduced oxides, EuWO{sub 4} and EuMoO{sub 4}, were synthesized via an in situ reduction of Eu{sup 3+} to Eu{sup 2+} under flux method using Mo, W, and Zn as metal reducing agents. {sup 151}Eu Mössbauer spectroscopy was used to analyze the relative Eu{sup 2+} and Eu{sup 3+} content of the samples. - Highlights: • K{sub 0.094}Eu{sub 0.906}MoO{sub 4}, K{sub 0.097}Eu{sub 0.903}WO{sub 4}, EuWO{sub 4}, and EuMoO{sub 4} have been synthesized and characterized. • The in situ reduction of Eu{sup 3+} to Eu{sup 2+} was carried out using Mo, W, and Zn as metal reducing agents. • Magnetic susceptibility data were collected. • {sup 151}Eu Mössbauer spectroscopy was used to analyze Eu{sup 2+} and Eu{sup 3+} content.

  9. Negative thermal expansion materials related to cubic zirconium tungstate

    NASA Astrophysics Data System (ADS)

    Lind, Cora

    2001-12-01

    A non-hydrolytic sol-gel method for the preparation of ZrW2O 8 was developed. A new trigonal polymorph was discovered, which is structurally related to trigonal ZrMO2O8 and MnRe2O 8 as evidenced by powder x-ray diffraction and EXAFS studies. Seeding of the starting mixtures with cubic ZrW2O8 promoted crystallization of the cubic phase instead of trigonal material. Dehydration of ZrW2O7(OH)2·2H 2O gave cubic ZrW2O8 at 650°C, and a modification of this route led to the discovery of the new NTE materials cubic ZrMo 2O8 and HfMo2O8. These compounds crystallize in the same temperature range as the more stable trigonal AMo2O 8 polymorphs. To facilitate preparation of phase pure cubic molybdates, the influence of precursor chemistry on the crystallization behavior was investigated. The synthesis was extended to the solid solution system ZrxHf 1-xMoyW2-yO8 (0 ≤ x ≤ 1, 0 ≤ y ≤ 2). All compounds showed negative thermal expansion between 77 and 573 K. High-pressure in situ diffraction experiments were conducted on several AM2O8 polymorphs. With the exception of monoclinic ZrMo2O8, all materials underwent at least one pressure induced phase transition. Quasi-hydrostatic experiments on cubic AMo 2O8 led to a reversible transition to a new high-pressure structure, while low-pressure amorphization was observed under non-hydrostatic conditions. Isothermal kinetic studies of the cubic to trigonal transformation for ZrMo2O8 were carried out on four samples. Apparent activation energies of 170--290 kJ/mol were obtained using an Avrami model in combination with an Arrhenius analysis. This corresponds to 5% conversion levels after one year at temperatures between 220 and 315°C. Ex situ studies showed that the conversion at lower temperatures was considerably slower than what would be expected from extrapolation of the kinetic data. Drop solution calorimetry was carried out on several polymorphs of ZrMo 2O8, HfMo2O8 and ZrW2O 8. Only monoclinic ZrMo2O8 was enthalpically stabilized with respect to the binary oxides. For all other polymorphs, the differences in enthalpies of formation from the binary oxides for each AM2O 8 system (A = Zr, Hf; M = Mo, W) were small. Attempts to synthesize new materials MIIRe2O 8 (M = Mg, Zn, Mn, Co) with the cubic ZrW2O8 structure from a hydrate precursor were not successful.

  10. The improved scintillation crystal lead tungstate scintillation for PET

    NASA Astrophysics Data System (ADS)

    Wan, Youbao; WU, Rurong; Xiao, Linrong; Zhang, Jianxin; Yang, Peizhi; Yan, Hui

    2009-07-01

    As a valuable material for the detecting of γ-ray, PbWO4 and BaF2:PbWO4 crystals were grown by a novel multi-crucible temperature gradient system developed by ourselves. Utilizing a topical partial heating method, this system can form a topical partial high temperature in its hearth. Thus this system could melt raw materials in step by step as requirement. The advantage of this method is that there would be solid obstruct left on the melt in the procedure of the crystal growing up. The left obstruct could prevent the volatilization of the component in the melt. Hence it is helpful for the composition homogenization in the crystal. The system also offers a sustaining device for multi-crucibles and thus it can grow many crystals simultaneity. The optical properties and scintillation properties of the crystals were studied. The results reveal that the ions doping improves the scintillation properties of the crystal. The transmittance spectra show that the transmittance of BaF2:PbWO4 crystals are better than that of PbWO4 crystals. For the PbWO4 crystals, their absorption edge is at 325nm, and their maximum transmittance is 68%. For the BaF2:PbWO4 crystals, their absorption edge is at 325nm and their maximum transmittance is upto76%. The X-ray excited luminescence spectra shows that the luminescence peak is at 420nm for the samples of PbWO4 crystal while the peak is at 430nm for the samples of BaF2:PbWO4 crystal respectively. The luminescence intensity of the samples of BaF2:PbWO4 crystal is about two times than that of PbWO4 crystal. And their peak shape is different for the two kind of crystal. The light yield of BaF2:PbWO4 crystals is about 2.9 times than that of PbWO4 crystal Analyzing these scintillation properties, we find that the VPb 3+ and VO- defects do harm for the optical properties of the crystal. Ions doping method could reduce the defect concentration and improving its illumination performance of the crystal. Specially, the doped F- ions in O2- site can induce the aberrance of the [WO4]2- tetrahedron and form [WO3F]- tetrahedron which has more active blue light yield, thus improve the light yield of the crystal. The improved light yield of BaF2:PbWO4 crystals is valuable for the medical diagnosing instrument PET and CT with high resolving power

  11. Tin Tungstate Nanoparticles: A Photosensitizer for Photodynamic Tumor Therapy.

    PubMed

    Seidl, Carmen; Ungelenk, Jan; Zittel, Eva; Bergfeldt, Thomas; Sleeman, Jonathan P; Schepers, Ute; Feldmann, Claus

    2016-03-22

    The nanoparticulate inorganic photosensitizer β-SnWO4 is suggested for photodynamic therapy (PDT) of near-surface tumors via reiterated 5 min blue-light LED illumination. β-SnWO4 nanoparticles are obtained via water-based synthesis and comprise excellent colloidal stability under physiological conditions and high biocompatibility at low material complexity. Antitumor and antimetastatic effects were investigated with a spontaneously metastasizing (4T1 cells) orthotopic breast cancer BALB/c mouse model. Besides protamine-functionalized β-SnWO4 (23 mg/kg of body weight, in PBS buffer), chemotherapeutic doxorubicin was used as positive control (2.5 mg/kg of body weight, in PBS buffer) and physiological saline (DPBS) as a negative control. After 21 days, treatment with β-SnWO4 resulted in a clearly inhibited growth of the primary tumor (all tumor volumes below 3 cm(3)) as compared to the doxorubicin and DPBS control groups (volumes up to 6 cm(3)). Histological evaluations of lymph nodes and lungs as well as the volume of ipsilateral lymph nodes show a remarkable antimetastatic effect being similar to chemotherapeutic doxorubicin but-according to blood counts-at significantly reduced side effects. On the basis of low material complexity, high cytotoxicity under blue-light LED illumination at low dark and long-term toxicity, β-SnWO4 can be an interesting addition to PDT and the treatment of near-surface tumors, including skin cancer, esophageal/gastric/colon tumors as well as certain types of breast cancer. PMID:26894966

  12. DISPERSION POLYMERIZATION OF ACRYLONITRILE IN SUPERCRITICAL CARBON DIOXIDE. (R826115)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  13. Solubility parameter of poly(styrene-co-acrylonitrile)

    NASA Astrophysics Data System (ADS)

    Wohlfarth, Ch.

    This document is part of Subvolume D2 'Polymer Solutions - Physical Properties and their Relations I (Thermodynamic Properties: PVT -Data and miscellaneous Properties of polymer Solutions) of Volume 6 `Polymers' of Landolt-Börnstein - Group VIII `Advanced Materials and Technologies'.

  14. Catalyst for the manufacture of acrylonitrile and methacrylonitrile

    SciTech Connect

    Grasselli, R.K.; Miller, A.F.; Hardman, H.F.

    1989-09-05

    This patent describes a catalyst composition. It consists of the catalytic oxides of iron, bismuth, molybdenum and magnesium as essential components and optionally the oxides of cobalt, nickel, phosphorus and arsenic.

  15. Luminescence properties of europium?terbium double activated calcium tungstate phosphor*1

    NASA Astrophysics Data System (ADS)

    Nazarov, M. V.; Jeon, D. Y.; Kang, J. H.; Popovici, E.-J.; Muresan, L.-E.; Zamoryanskaya, M. V.; Tsukerblat, B. S.

    2004-08-01

    Double incorporation of Eu 3+ and Tb 3+ ions into a CaWO 4 crystalline lattice modifies the luminescence spectrum due to the formation of new emission centers. Depending on the activators concentration and nature, as well as on the interaction between the activators themselves, the luminescence color can be varied within the entire range of the visible spectrum. Variable luminescence was obtained when CaWO 4:Eu,Tb phosphors with 0-5 mol% activator ions were exposed to relatively low excitation energies as UV (365 and 254 nm). Under high energy excitation such as VUV (147 nm) radiation or electron beam, white light has been observed. This material with controlled properties seems to be promising for the applications in fluorescent lamps, colored lightning for advertisement industries, and other optoelectronic devices.

  16. Lead Tungstate and Silicon Photomultipliers for Transmission Z-spectroscopy in Cargo Inspection Systems

    NASA Astrophysics Data System (ADS)

    Langeveld, Willem G. J.; Janecek, Martin

    The bremsstrahlung X-ray spectrum in high-energy, high-intensity X-ray cargo inspection systems is attenuated and modified by cargo materials depending on the cargo atomic number (Z). Spectroscopy of transmitted x rays is thus useful to measure the approximate Z of the cargo. Due to the broad features of the energy spectrum, excellent energy resolution is not required. Such "Z-Spectroscopy" (Z-SPEC) is possible at low enough count rates. A statistical approach, Z-SCAN (Z-determination by Statistical Count-rate ANalysis), can also be used, complementing Z-SPEC at high count rates. Both approaches require fast X-ray detectors and fast digitizers. Z-SPEC, in particular, benefits from very fast scintillators, in order to avoid signal pile-up.Preferentially, Z-SPEC, Z-SCAN and cargo imaging are implemented in a single detector array to reduce system cost, weight, and complexity. To preserve good spatial resolution of the imaging subsystem, dense scintillators are required. Previously, we studied ZnO, BaF2 and PbWO4, as well as suitable photo-detectors, read-out electronics and digitizers. ZnO is not suitable because it self-absorbs its scintillation light. BaF2 emits in the UV, either requiring fast wavelength shifters or UV-sensitive solid state read-out devices, and it also has a long decay time component. PbWO4 is currently the most attractive choice because it does not have these problems, but it is significantly slower and has low light output. There is thus a need for alternative fast high-density scintillators that emit visible light. Alternatively, there is a need for a fast solid-state read-out device that is sensitive to UV light for use with BaF2, or other UV-emitting scintillators. Here, we present results of tests performed with PbWO4 crystals, reflector materials and silicon photomultipliers.

  17. Synthesis of zirconium tungstate-zirconia core-shell composite particles

    SciTech Connect

    Khazeni, Nasser; Mavis, Bora; Guenduez, Guengoer; Colak, Uner

    2011-11-15

    Highlights: {yields} ZrW{sub 2}O{sub 8}-ZrO{sub 2} core-shell particles to offer solutions for sintering problems. {yields} Core synthesis by a precursor based on tungstic acid and zirconium acetate. {yields} Shell phase by urea hydrolysis in the presence of zirconium ions. {yields} [Urea]/[ZrOCl{sub 2}] ratio controls the rate of shell precursor precipitation. -- Abstract: In this work, ZrW{sub 2}O{sub 8}-ZrO{sub 2} core-shell composite particles were synthesized. ZrW{sub 2}O{sub 8} that was used in the core is a material with negative coefficient of thermal expansion, and it was synthesized from a high-pH precursor based on use of tungstic acid and zirconium acetate. Shell layer was composed of ZrO{sub 2} nanocrystallites and precipitated from an aqueous solution by urea hydrolysis. While volume of the shell was effectively controlled by the initial zirconium ion concentration in the solutions, the rate of precipitation was a function of the ratio of initial concentrations of urea to zirconium ions. It is hypothesized that isolation of the ZrW{sub 2}O{sub 8} within a layer of ZrO{sub 2}, will be a key element in solving problems associated with reactivity of ZrW{sub 2}O{sub 8} towards other components in sintering of ceramic-ceramic composites with tuned or zero thermal expansion coefficient.

  18. Copper-zirconium tungstate composites exhibiting low and negative thermal expansion influenced by reinforcement phase transformations

    NASA Astrophysics Data System (ADS)

    Balch, Dorian K.; Dunand, David C.

    2004-03-01

    A fully-dense Cu-75 vol pct ZrW2O8 metal matrix composite was fabricated by hot isostatic pressing of Cu-coated ZrW2O8 particles. A small amount of the high-pressure γ-ZrW2O8 phase was created during the cooldown and depressurization following densification; near complete transformation to γ-ZrW2O8 was achieved by subsequent cold isostatic pressing. The thermal expansion behavior of the composite between 25°C and 325°C was altered by the cold isostatic pressing treatment, and also depended on the length of time that had passed between thermal cycles. The measured thermal expansion coefficients within specific temperature ranges varied from -6·10-6 K-1 to far above the thermal expansion coefficient of the copper matrix. The complex temperature-dependent expansion/contraction behavior could be justified by considering the evolution of phase transformations taking place in the ZrW2O8 phase, which were observed by in-situ synchrotron X-ray diffraction measurements.

  19. Polishing procedure and surface characterization lead tungstate crystal scintillator Road No. 723 and No. 754

    SciTech Connect

    Kellam, M

    1996-05-01

    Step by step procedures are given for polishing the scintillator rods. A Strasbaugh spindle polishing machine was used along with visual inspection and hand polishing. Extensive data is given on pre-polish surface characterization, profilometry, microphotography, and interferometry.

  20. Pressure-induced elastic softening of monocrystalline zirconium tungstate at 300K

    NASA Astrophysics Data System (ADS)

    Pantea, C.; Migliori, A.; Littlewood, P. B.; Zhao, Y.; Ledbetter, H.; Lashley, J. C.; Kimura, T.; van Duijn, J.; Kowach, G. R.

    2006-06-01

    The elastic tensor of monocrystalline ZrW2O8 was determined near 300K as a function of pressure, using pulse-echo ultrasound in a large-volume moissanite anvil cell. An unusual decrease in bulk modulus with increased pressure was observed. A framework-solid-based nonlinear model with many degrees of freedom predicts the observed behavior. We also observe that ReO3 , a similar framework solid but lacking the necessary degrees of freedom, fails to display softening. Additionally, the pressure-induced phase transition from α-ZrW2O8 (cubic) to γ-ZrW2O8 (orthorhombic) is found to take place at ≈0.5GPa , a result confirmed by Raman spectroscopy.

  1. Formation of tungsten monocarbide from a molten tungstate-halide phase by gas sparging

    SciTech Connect

    Gomes, J.M.; Raddatz, A.E.; Baglin, E.G.

    1988-02-23

    A process for preparation of tungsten monocarbide is described comprising: (a) providing a molten composition comprising an alkali metal halide and an oxygen compound of tungsten; (b) sparging the composition with a gas comprising a gaseous hydrocarbon which is selected from the group consisting of natural gas, methane, ethane, acetylene, propane, butane, mixtures thereof, and admixtures of these gases with H/sub 2/ or CO, at a temperature of about 900/sup 0/ to 1100/sup 0/C for a sufficient time for the tungsten compound to be substantially converted to tungsten carbide; and (c) decanting the molten halide from the tungsten carbide product.

  2. Tungstate sharpening: A versatile method for extending the profile of ultra sharp tungsten probes

    NASA Astrophysics Data System (ADS)

    Stone, R.; Rosamond, M.; Coleman, K.; Petty, M.; Kolosov, O.; Bowen, L.; Dubrovskii, V.; Zeze, D.

    2013-03-01

    The benefits of a new electrochemical etching method for the controlled sharpening of sub-micron tungsten probes are demonstrated. The proposed technique only utilizes the insulating effect of the WO42- by-product which offers more practical ways of controlling the process parameters. The electrosharpening method was fully automated through the analysis of the process current, bulk coulometry, shadowgraphs, and time lapse microscopy. Tip radii smaller than 15 nm were maintained over a wide range of controlled lengths up to 4.5 mm with conic angles of less than 1°.

  3. Polypyrrole-encapsulated iron tungstate nanocomposites: a versatile platform for multimodal tumor imaging and photothermal therapy

    NASA Astrophysics Data System (ADS)

    Xiao, Zhiyin; Peng, Chen; Jiang, Xiaohong; Peng, Yuxuan; Huang, Xiaojuan; Guan, Guoqiang; Zhang, Wenlong; Liu, Xiaoming; Qin, Zongyi; Hu, Junqing

    2016-06-01

    A versatile nanoplatform of FeWO4@Polypyrrole (PPy) core/shell nanocomposites, which was facilely fabricated by first hydrothermal synthesis of FeWO4 nanoparticles and subsequent surface-coating of polypyrrole shell, was developed as an effective nanotheranostic agent of cancer. The as-prepared nanocomposites demonstrated excellent dispersion in saline, long-term colloidal storage, outstanding photo-stability and high photothermal efficiency in solution. In particular, FeWO4@PPy exhibited efficient performance for hyperthermia-killing of cancer cells under the irradiation of an 808 nm laser, accompanied with multimodal contrast capabilities for magnetic resonance imaging, X-ray computed tomography and infrared thermal imaging in vitro and in vivo. Furthermore, the nanocomposites presented impactful tumor growth inhibition and good biocompability in animal experiments. Blood circulation and biodistribution of the nanocomposites were also investigated to understand their in vivo behaviours. Our results verified the platform of FeWO4@PPy nanocomposites as a promising photothermal agent for imaging-guided cancer theranostics.A versatile nanoplatform of FeWO4@Polypyrrole (PPy) core/shell nanocomposites, which was facilely fabricated by first hydrothermal synthesis of FeWO4 nanoparticles and subsequent surface-coating of polypyrrole shell, was developed as an effective nanotheranostic agent of cancer. The as-prepared nanocomposites demonstrated excellent dispersion in saline, long-term colloidal storage, outstanding photo-stability and high photothermal efficiency in solution. In particular, FeWO4@PPy exhibited efficient performance for hyperthermia-killing of cancer cells under the irradiation of an 808 nm laser, accompanied with multimodal contrast capabilities for magnetic resonance imaging, X-ray computed tomography and infrared thermal imaging in vitro and in vivo. Furthermore, the nanocomposites presented impactful tumor growth inhibition and good biocompability in animal experiments. Blood circulation and biodistribution of the nanocomposites were also investigated to understand their in vivo behaviours. Our results verified the platform of FeWO4@PPy nanocomposites as a promising photothermal agent for imaging-guided cancer theranostics. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr03336a

  4. Single Unit Cell Bismuth Tungstate Layers Realizing Robust Solar CO2 Reduction to Methanol.

    PubMed

    Liang, Liang; Lei, Fengcai; Gao, Shan; Sun, Yongfu; Jiao, Xingchen; Wu, Ju; Qamar, Shaista; Xie, Yi

    2015-11-16

    Solar CO2 reduction into hydrocarbons helps to solve the global warming and energy crisis. However, conventional semiconductors usually suffer from low photoactivity and poor photostability. Here, atomically-thin oxide-based semiconductors are proposed as excellent platforms to overcome this drawback. As a prototype, single-unit-cell Bi2WO6 layers are first synthesized by virtue of a lamellar Bi-oleate intermediate. The single-unit-cell thickness allows 3-times larger CO2 adsorption capacity and higher photoabsorption than bulk Bi2WO6. Also, the increased conductivity, verified by density functional theory calculations and temperature-dependent resistivities, favors fast carrier transport. The carrier lifetime increased from 14.7 to 83.2 ns, revealed by time-resolved fluorescence spectroscopy, which accounts for the improved electron-hole separation efficacy. As a result, the single-unit-cell Bi2WO6 layers achieve a methanol formation rate of 75 μmol g(-1) h(-1), 125-times higher than that of bulk Bi2WO6. The catalytic activity of the single-unit-cell layers proceeds without deactivation even after 2 days. This work will shed light on designing efficient and robust photoreduction CO2 catalysts.

  5. Studies of lead tungstate crystals for the ALICE electromagnetic calorimeter PHOS

    NASA Astrophysics Data System (ADS)

    Ippolitov, M.; Beloglovsky, S.; Bogolubsky, M.; Burachas, S.; Erin, S.; Klovning, A.; Kuriakin, A.; Lebedev, V.; Lobanov, M.; Maeland, O.; Manko, V.; Nikulin, S.; Nyanin, A.; Odland, O. H.; Punin, V.; Sadovsky, S.; Samoilenko, V.; Sibiriak, Yu.; Skaali, B.; Tsvetkov, A.; Vinogradov, Yu.; Vasiliev, A.

    2002-06-01

    Full-size (22×22×180 mm 3) A LICE crystals were delivered by "North Crystals" company, Apatity, Russia. These crystals were tested with test benches, specially built for measurements of the crystals optical transmission and light yield. Beam-test results of different sets of 3×3 matrices with Hamamatsu APD light readout are presented. Data were taken at electron momenta from 600 MeV/ c up to 10 GeV/ c. Energy resolution and linearity curves are measured. The tests were carried out at the C ERN PS and SPS secondary beam-lines.

  6. Characterization of Lead Tungstate for Neutral Particle Spectrometer at 12 GeV JLab

    NASA Astrophysics Data System (ADS)

    Runyon, Christian

    2015-10-01

    Precision measurements of the deeply-virtual Compton scattering cross section at different beam energies to extract the real part of the Compton form factor, measurements to push the energy scale of real Compton scattering, and measurements of the basic semi-inclusive neutral-pion cross section in a kinematical region where the QCD factorization scheme is expected to hold all have something in common: the need for detecting neutral particles with high precision and high luminosity. The Neutral Particle Spectrometer (NPS) is a crystal electromagnetic calorimeter preceded by a sweeping magnet to sweep away charged particles. In this presentation I will show the results of PbWO4 crystal quality studies for the NPS. PbWO4 is optimal for the NPS due to its small Moliere radius and radiation hardness. The critical aspect for crystal quality, and thus resolution/precision, is the combination of high light output and radiation hardness, which depend strongly on the manufacturing process. We have tested the performance of PbWO4 crystals, and in particular, measured their light yield, optical transmission, and uniformity and radiation hardness. The homogeneity of the crystal was investigated based on the variation of the transverse optical transmission. Supported in part by NSF-PHY-1306227.

  7. Random lasing in Nd{sup 3+} doped potassium gadolinium tungstate crystal powder

    SciTech Connect

    Moura, André L.; Fewo, Serge I.; Carvalho, Mariana T.; Gomes, Anderson S. L.; Araújo, Cid B. de; Kuzmin, Andrey N.; Prasad, Paras N.

    2015-02-28

    Random laser (RL) emission in Nd{sup 3+} doped potassium gadolinium tungstate—KGd(WO{sub 4}){sub 2}:Nd{sup 3+}—crystal powder is demonstrated. The powder was excited at 813 nm in resonance with the Nd{sup 3+} transition {sup 4}I{sub 9/2}→{sup 4}F{sub 5/2}. RL emission at 1067 nm due to the {sup 4}F{sub 3/2}→{sup 4}I{sub 11/2} transition was observed and characterized. An intensity threshold dependent on the laser spot area and bandwidth narrowing from ≈2.20 nm to ≈0.40 nm were observed and measured. For a beam spot area of 0.4 mm{sup 2}, a RL threshold of 6.5 mJ/mm{sup 2} (90 MW/cm{sup 2}) was determined. For excitation intensity smaller than the RL threshold, only spontaneous emission from level {sup 4}F{sub 3/2} with decay time in the tens microsecond range was observed, but for excitation above the RL threshold, significant shortening of excited level lifetime, characteristic of a stimulated process was found. The overall characteristics measured show that KGd(WO{sub 4}){sub 2}:Nd{sup 3+} is an efficient material for operation of solid state RLs in the near-infrared.

  8. Evaluation of lanthanum tungstates as electrolytes for proton conductors Solid Oxide Fuel Cells

    NASA Astrophysics Data System (ADS)

    Zayas-Rey, M. J.; dos Santos-Gómez, L.; Porras-Vázquez, J. M.; Losilla, E. R.; Marrero-López, D.

    2015-10-01

    La27W4NbO55-δ (LWNO) has been tested as electrolyte for proton conductor Solid Oxide Fuel Cells (PC-SOFCs). For this purpose, different electrodes and composite electrodes are considered, including: La0.8Sr0.2MnO3-δ, La0.6Sr0.4Co1-xFexO3-δ, La0.75Sr0.25Cr0.5Mn0.5O3-δ, SrFe0.75Nb0.25O3-δ and NiO. Chemical compatibility between the cell components is investigated by X-ray powder diffraction (XRPD) and energy dispersive spectroscopy (EDS). Furthermore, area specific resistance (ASR) for the different electrodes is determined in symmetrical cells by impedance spectroscopy. XRPD and EDS analysis does not reveal significant bulk reactivity between most of these electrodes and LWNO electrolyte in the typical operating temperature range of an SOFC (600-900 °C). However, minor interdiffusion of elements at the electrolyte/electrode interface has negative effects on both the ohmic losses and electrode polarization of the cells. ASR values are significantly improved by using a porous buffer layer of Ce0.8Gd0.2O1.9 (CGO), deposited between the electrolyte and electrode materials, to prevent reactivity. A single cell with a 350 μm-thick electrolyte, NiO-CGO and La0.6Sr0.4Co0.8Fe0.2O3-δ-CGO composite as anode and cathode, respectively, generates maximum power densities of 140 and 18 mWcm-2 at 900 and 650 °C, respectively.

  9. Structural and optical studies of cerium doped lead tungstate nano phosphor

    NASA Astrophysics Data System (ADS)

    Tawde, Dharmendra V.

    The rapidly expanding oil sands of western Canada, the third largest reserves in the world, are creating serious challenges, such as ecological harm, labour shortages, and extensive natural gas consumption. This thesis develops three practical real options models to evaluate the feasibility of oil sands projects and to estimate the optimal rate of oil sands expansion, while accounting for the stated concerns. (Abstract shortened by UMI.).

  10. Polypyrrole-encapsulated iron tungstate nanocomposites: a versatile platform for multimodal tumor imaging and photothermal therapy.

    PubMed

    Xiao, Zhiyin; Peng, Chen; Jiang, Xiaohong; Peng, Yuxuan; Huang, Xiaojuan; Guan, Guoqiang; Zhang, Wenlong; Liu, Xiaoming; Qin, Zongyi; Hu, Junqing

    2016-07-14

    A versatile nanoplatform of FeWO4@Polypyrrole (PPy) core/shell nanocomposites, which was facilely fabricated by first hydrothermal synthesis of FeWO4 nanoparticles and subsequent surface-coating of polypyrrole shell, was developed as an effective nanotheranostic agent of cancer. The as-prepared nanocomposites demonstrated excellent dispersion in saline, long-term colloidal storage, outstanding photo-stability and high photothermal efficiency in solution. In particular, FeWO4@PPy exhibited efficient performance for hyperthermia-killing of cancer cells under the irradiation of an 808 nm laser, accompanied with multimodal contrast capabilities for magnetic resonance imaging, X-ray computed tomography and infrared thermal imaging in vitro and in vivo. Furthermore, the nanocomposites presented impactful tumor growth inhibition and good biocompability in animal experiments. Blood circulation and biodistribution of the nanocomposites were also investigated to understand their in vivo behaviours. Our results verified the platform of FeWO4@PPy nanocomposites as a promising photothermal agent for imaging-guided cancer theranostics. PMID:27303912

  11. Quantitative analysis of (styrene/acrylonitrile/methyl methacrylate) co-polymer systems by infrared resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    Jalbout, Abraham F.; Jiang, Tao; Fengqi, Liu; Ding, C.; Darwish, Abdalla M.

    2002-02-01

    A detailed careful analysis of the infrared resonance (IR) spectra of polystyrene (PSt), polymethyl methacrylate (PMMA), polyacrylonitrile (PAN) and their co-mixtures were performed. Through this study the absorption peak area to weight ratios as well as working curves were obtained to test for their reliability as well as their suitability. Satisfactory results were achieved and these working curves were then used to measure the polymerized components of binary and ternary co-polymers. By investigating the acquired data we conclude that the monomer preferential polymeric sequence is St>MMA>AN. A quantitative method to measure P (St/AN/MMA) concentrations by IR spectroscopy is proposed in this work.

  12. 21 CFR 177.1040 - Acrylonitrile/styrene copoly-mer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as...: Substances Limitation Condensation polymer of toluene sulfonamide and formaldehyde 0.15 pct maximum. (c... Sieve No. 10 is extracted with 250 mil of deionized water or reagent grade n-heptane at...

  13. 21 CFR 177.1040 - Acrylonitrile/styrene copoly-mer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as...: Substances Limitation Condensation polymer of toluene sulfonamide and formaldehyde 0.15 pct maximum. (c... Sieve No. 10 is extracted with 250 mil of deionized water or reagent grade n-heptane at...

  14. 21 CFR 177.1030 - Acrylonitrile/butadiene/styrene/methyl methacrylate copolymer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... acetic acid, 50 percent ethanol, and n-heptane for 10 days at 120 °F. (2) The finished food-contact... to distilled water, 3 percent acetic acid and n-heptane at 190 °F for 2 hours, cooled to 120 °F...

  15. 21 CFR 177.1030 - Acrylonitrile/butadiene/styrene/methyl methacrylate copolymer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... acetic acid, 50 percent ethanol, and n-heptane for 10 days at 120 °F. (2) The finished food-contact... to distilled water, 3 percent acetic acid and n-heptane at 190 °F for 2 hours, cooled to 120 °F...

  16. 21 CFR 177.1030 - Acrylonitrile/butadiene/styrene/methyl methacrylate copolymer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... acetic acid, 50 percent ethanol, and n-heptane for 10 days at 120 °F. (2) The finished food-contact... to distilled water, 3 percent acetic acid and n-heptane at 190 °F for 2 hours, cooled to 120 °F...

  17. 21 CFR 177.1030 - Acrylonitrile/butadiene/styrene/methyl methacrylate copolymer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    .../federal_register/code_of_federal_regulations/ibr_locations.html. (d) Extractive limitations. (1) Total... regulations in this part, and the following: Substances Limitations 2-Mercaptoethanol The finished copolymer..., call 202-741-6030, or go to:...

  18. Coconut shell powder as cost effective filler in copolymer of acrylonitrile and butadiene rubber.

    PubMed

    Keerthika, B; Umayavalli, M; Jeyalalitha, T; Krishnaveni, N

    2016-08-01

    Filler is one of the major additives in rubber compounds to enhance the physical properties. Even though numerous benefits obtained from agricultural by products like coconut shell, rice husk etc., still they constitute a large source of environmental pollution. In this investigation, one of the agricultural bye product coconut shell powder (CSP) is used as filler in the compounding KNB rubber. It shows the positive and satisfied result was achieved only by the use of filler Fast Extrusion Furnace (FEF) and coconut shell powder (CSP) which was used 50% in each. The effect of these fillers on the mechanical properties of a rubber material at various loading raging from 0 to 60PHP was studied. Mercaptodibanzothiazole disulphide (MBTS) was used as an accelerator. The result shows that presence of 25% and 50% of the composites has better mechanical properties like Hardness, Tensile strength, Elongation at break and Specific gravity when compared with other two combinations. Even though both 25% and 50% of composites shows good mechanical properties, 50% of CSP have more efficient than 25% of CSP. PMID:27060197

  19. Synthesis and biological evaluation of sulfonyl acrylonitriles as novel inhibitors to peritoneal carcinomatosis.

    PubMed

    Zificsak, Craig A; Shen, Yi; Lisko, Joseph G; Theroff, Jay P; Lao, Xuegang; Bollt, Oana; Li, Xiufen; Dorsey, Bruce D; Kuwada, Scott K

    2012-03-01

    The vast majority of cancer patients die from metastasis, the process by which cancer cells spread to secondary tissues through body fluids. Peritoneal carcinomatosis is a type of metastasis in which cancer cells gain access to the intra-abdominal cavity and then implant in the peritoneum, the thin tissue that lines the abdominal wall and internal organs. Unfortunately, peritoneal carcinomatosis can occur following surgical resection of intra-abdominal malignancies. We previously reported proapoptotic activity of (2E)-3-[[4-(1,1-dimethylethyl)phenyl]sulfonyl]-2-propenenitrile (BAY 11-7085, 1) on colon and pancreatic cancer cells during adhesion and demonstrated that this compound could significantly inhibit peritoneal carcinomatosis in mice.(1,2) In order to determine the chemical basis of the anti-metastatic properties of BAY 11-7085, a series of analogs were synthesized and evaluated for their ability to induce apoptosis in pancreatic and ovarian cancer cells during adhesion to mesothelial cells, which line the surface of the peritoneum. The co-culture assay results were validated using a murine peritoneal carcinomatosis model. These analogs may greatly benefit patients undergoing surgical resections of colorectal, pancreatic, and ovarian cancers depending on their tolerability.

  20. 76 FR 54228 - Draft Toxicological Review of Acrylonitrile: In Support of Summary Information on the Integrated...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-31

    ... (76 FR 38387) for the external review draft human health assessment titled, ``Toxicological Review of... INFORMATION section of the previous Federal Register Notice (76 FR 38387). Additional Information: For... Risk Information System (IRIS) AGENCY: Environmental Protection Agency (EPA). ACTION: Notice...

  1. 76 FR 38387 - Draft Toxicological Review of Acrylonitrile: In Support of Summary Information on the Integrated...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-30

    ... Risk Information System (IRIS) AGENCY: Environmental Protection Agency (EPA). ACTION: Notice of public... (IRIS)'' (EPA/ 635/R-08/013A). The draft assessment was prepared by the National Center for... technical comments on draft IRIS health assessments to EPA and other interested parties attending...

  2. Structure and activity of tellurium/molybdenum oxide acrylonitrile catalysts. [Ammoxidation

    SciTech Connect

    Bart, J.C.J.; Giordano, N.

    1980-08-01

    The tellurium/molybdenum mixed oxides ((TeMo)O) catalyst system was investigated as part of the development of an industrial cerium/tellurium/molybdenum mixed oxides catalyst for propylene ammoxidation Catalysts containing 25% active phase on silica were prepared, characterized by BET surface area measurement, mercury porosimetry, X-ray diffraction, and optical microscopy, and tested for the ammoxidation of propylene at 400/sup 0/-460/sup 0/C in a flow reactor. The results suggested that Te/sub 2/MoO/sub 7/ is the active phase. The mechanism probably involves activation of propylene on a tellurium site and oxygen insertion at isolated and highly distorted MoO/sub 6/ octahedral sites. The addition of cerium to the binary catalyst prevents the reductive degradation of (TeMo)O which occurs under reactor flow conditions by a phase-separation process.

  3. The photodissociation mechanisms of acrylonitrile: Ab initio calculations on reaction channels and surface intersections

    SciTech Connect

    Du Weina; Luo Cheng; Li Zesheng

    2008-11-07

    The dissociations of CH{sub 2}CHCN into CH{sub 2}CH+CN and CH{sub 2}C+HCN in the S{sub 0}, T{sub 1}, and {sup 1}{pi}{sub 2}{pi}{sub C{identical_to}}{sub N}* (definitions of {pi} orbitals can refer to computational details) states, have been explored at the complete active space self-consistent field level of theory employing the Dunning correlation consistent triple-zeta basis set. The lowest energy points of the surface crossing seams have been searched. Two conical intersections, from {sup 1}{pi}{sub C{identical_to}}{sub N}{pi}{sub 1}* to {sup 1}{pi}{sub 2}{pi}{sub 1}* (CI{sub 1}) and from {sup 1}{pi}{sub 2}{pi}{sub 1}* to S{sub 0} (CI{sub 2}), and one intersystem crossing point (T{sub 1}/S{sub 0}) have been located. The energies of all critical points have been recomputed with the multiconfigurational second-order perturbation method. At each conical intersection, derivative coupling and unscaled gradient difference vectors have been analyzed to determine the relaxation channels that the molecule may evolve in after nonradiative decay. Once the molecule is photoexcited to the {sup 1}{pi}{sub 2}{pi}{sub 1}* or {sup 1}{pi}{sub C{identical_to}}{sub N}{pi}{sub 1}* state, it would relax along the similar pathway: funneling through CI{sub 1} and then CI{sub 2}, and finally populate the ground state. Our results show that upon 193 nm photoexcitation, the most probable reaction channel is the ground-state HCN elimination following radiationless decays from excited states through surface crossings, which consists with experimental results J. Chem. Phys. 108, 5784 (1998). The investigated dissociation channels on the {sup 1}{pi}{sub 2}{pi}{sub C{identical_to}}{sub N}* surface, which are inaccessible upon 193 nm photoexcitation, may provide information for reactions induced by higher energy excitations.

  4. A comparison of the characteristics of excimer and femtosecond laser ablation of acrylonitrile butadiene styrene (ABS)

    NASA Astrophysics Data System (ADS)

    See, Tian Long; Liu, Zhu; Li, Lin; Zhong, Xiang Li

    2016-02-01

    This paper presents an investigation on the ablation characteristics of excimer laser (λ = 248 nm, τ = 15 ns) and femtosecond laser (λ = 800 nm, τ = 100 fs) on ABS polymer sheets. The laser-material interaction parameters (ablation threshold, optical penetration depth and incubation factor) and the changes in material chemical properties were evaluated and compared between the two lasers. The work shows that the ablation threshold and effective optical penetration depth values are dependent on the wavelength of laser beam (photon energy) and the pulse width. The ablation threshold value is lower for the excimer laser ablation of ABS (Fth = 0.087 J/cm2) than that for the femtosecond laser ablation of ABS (Fth = 1.576 J/cm2), demonstrating a more dominating role of laser wavelength than the pulse width in influencing the ablation threshold. The ablation depth versus the logarithmic scale of laser fluence shows two linear regions for the fs laser ablation, not previously known for polymers. The effective optical penetration depth value is lower for excimer laser ablation (α-1 = 223 nm) than that for femtosecond laser ablation (α-1 = 2917 nm). The ablation threshold decreases with increasing number of pulses (NOP) due to the chain scission process that shortens the polymeric chains, resulting in a weaker polymeric configuration and the dependency is governed by the incubation factor. Excimer laser treatment of ABS eliminates the Cdbnd C bond completely through the chain scission process whereas Cdbnd C bond is partially eliminated through the femtosecond laser treatment due to the difference in photon energy of the two laser beams. A reduction in the Cdbnd C bond through the chain scission process creates free radical carbons which then form crosslinks with each other or react with oxygen, nitrogen and water in air producing oxygen-rich (Csbnd O and Cdbnd O bond) and nitrogen-rich (Csbnd N) functional groups.

  5. Highly active magnetic bismuth tungstate/magnetite composite under visible light irradiation in the presence of hydrogen peroxide.

    PubMed

    Shan, Guoqiang; Fu, Yu; Chu, Xiaolong; Chang, Chun; Zhu, Lingyan

    2015-04-15

    Bi2WO6/Fe3O4 composites were synthesized using hydrothermal method and their photocatalytic activity to degrade rhodamine B (RhB) under visible light irradiation assisted with H2O2 and underlying mechanisms were investigated. The composites were 3D flower-like microspheres constructed by 2D Bi2WO6 nanosheets loaded with spherical Fe3O4 nanoparticles. The composited photocatalysts could be easily harvested from the reaction solution by an external magnetic field. In the presence of H2O2, a large amount of hydroxyl radicals (·OHs) were produced by H2O2 reacting with photogenerated electrons. Fe3O4 not only promoted the separation of hole-electron pairs but also acted as a Fenton-like reagent, expediting the production of ·OH. Thus, the composites in the presence of H2O2 displayed much higher photocatalytic efficiency to degrade RhB than pure Bi2WO6. 98% of RhB (initial concentration 10 mg/L) was degraded in 2 h visible irradiation and 60% of total organic carbon (TOC) was removed in 3 h by 0.5 g/L Bi2WO6/Fe3O4 (5:1). The composite displayed high photodegradation efficiency at pH 3-9. Our study suggests that a visible light driven and highly active magnetic photocatalyst-Fenton coupling oxidation system may have potential application in water treatment and environmental cleaning. PMID:25594803

  6. Structural, thermal, optical properties and simulation of white light of titanium-tungstate-tellurite glasses doped with dysprosium

    SciTech Connect

    Jyothi, L.; Upender, G.; Kuladeep, R.; Rao, D. Narayana

    2014-02-01

    Graphical abstract: CIE coordinate diagram of different concentrations of the Dy{sup 3+}-doped TTWD glasses with coordinates in the white light region. - Highlights: • Radiative lifetime of {sup 4}F{sub 9/2} level of Dy{sup 3+} ions is longer in the tellurite glass. • Quantum efficiency is found to be high. • These glasses are suitable materials for generating white light. - Abstract: Structural, thermal, optical properties and simulation of white light of Dy{sup 3+}-doped tellurite glasses of composition TTWD: (75 − x)TeO{sub 2} − 10TiO{sub 2} − 15WO{sub 3} − xDy{sub 2}O{sub 3} (x = 0, 0.1, 0.5, 1.0 and 2.0 mol%) were investigated. Raman spectra revealed that the glass contains TeO{sub 4}, TeO{sub 3}, WO{sub 4} and WO{sub 6} units. Differential scanning calorimetry (DSC) measurements were carried out to measure the glass transition temperature of all the glasses. From the optical absorption spectra, luminescence spectra and using the Judd–Ofelt (JO) analysis, we estimated the radiative transition probabilities, emission cross-sections, branching ratios and radiative lifetimes. The decay curves at lower concentrations are exponential while they show a non-exponential behavior at higher concentrations (≥0.5 mol%) due to energy transfer processes. The effective lifetime for the {sup 4}F{sub 9/2} level decreases with increase in Dy{sub 2}O{sub 3} concentration for the glasses under investigation. The non-exponential decay curves could fit well to the Inokuti–Hirayama (IH) model with S = 6, indicating that the nature of interaction responsible for energy transfer is of dipole–dipole type. Simulation of white light is examined with varying concentration and the results indicate that these glasses are suitable for white light emitting diode applications.

  7. Tungsten bronze-based nuclear waste form ceramics. Part 1. Conversion of microporous tungstates to leach resistant ceramics

    NASA Astrophysics Data System (ADS)

    Luca, Vittorio; Griffith, Christopher S.; Drabarek, Elizabeth; Chronis, Harriet

    2006-11-01

    The effective immobilization of Cs + and/or Sr 2+ sorbed on hexagonal tungsten oxide bronze (HTB) adsorbent materials has been achieved by heating in air at temperatures in the range 500-1000 °C. Crystalline powdered HTB materials formed by heating at 800 °C displayed leach characteristics comparable to Cs-containing hot-pressed hollandites in the pH range from 0 to 12. If the Cs-loaded HTB sorbents were pressed into pellets prior to calcination, ceramic monoliths could be prepared with negligible Cs volatilization losses. Heating to temperatures in excess of 1250 °C under dynamic air flow resulted in the melting of the sorbent to form phase assemblages consisting of millimetre-sized crystals of bronzoid phases. Up to 5 wt% mass loss was observed for small scale samples of melted materials under dynamic air flow. Both the calcined and melted bronzoid waste forms are multiphase ceramics in which Cs + remains bound within, and appears to stabilize, the hexagonal bronze phase, even after complete melting at 1300 °C. The leachability of Sr from the phases prepared by heating appears to be somewhat worse than that of Cs. Saturation of the HTB adsorbents with lanthanide elements (Nd, La, Ce) gave rise to cubic bronze phases in which we propose that the lanthanides substitute at the tungsten or molybdenum sites rather than the tunnel positions. The lanthanides were rather easily leached from the calcined phases in 0.1 M HNO 3 at 150 °C.

  8. (Z)-3-(Benzo[b]thiophen-2-yl)-2-(3,4,5-trimethoxyphenyl)acrylonitrile and (E)-3-(benzo[b]thiophen-2-yl)-2-(3,4-dimethoxyphenyl)acrylonitrile. [corrected].

    PubMed

    Sonar, Vijayakumar N; Parkin, Sean; Crooks, Peter A

    2007-12-01

    The title compounds, C20H17NO3S, (I), and C19H15NO2S, (II), were prepared by the reaction of benzo[b]thiophene-2-carbaldehyde with (3,4,5-trimethoxyphenyl)acetonitrile and (3,4-dimethoxyphenyl)acetonitrile, respectively, in the presence of methanolic potassium hydroxide. In (I), the C=C bond linking the benzo[b]thiophene and the 3,4,5-trimethoxyphenyl units has E geometry, with dihedral angles between the plane of the bridging unit and the planes of the two adjacent ring systems of 5.2 (3) and 13.1 (2) degrees, respectively. However, in (II), the C=C bond has Z geometry, with dihedral angles between the plane of the bridging unit and the planes of the adjacent benzo[b]thiophene and 3,4-dimethoxyphenyl units of 4.84 (17) and 76.09 (7) degrees, respectively. There are no significant intermolecular hydrogen-bonding interactions in the packing of (I) and (II). The packing is essentially stabilized via van der Waals forces.

  9. Conformational and Molecular Structures of α,β-Unsaturated Acrylonitrile Derivatives: Photophysical Properties and Their Frontier Orbitals.

    PubMed

    Percino, María Judith; Cerón, Margarita; Rodríguez, Oscar; Soriano-Moro, Guillermo; Castro, María Eugenia; Chapela, Víctor M; Siegler, Maxime A; Pérez-Gutiérrez, Enrique

    2016-03-28

    We report single crystal X-ray diffraction (hereafter, SCXRD) analyses of derivatives featuring the electron-donor N-ethylcarbazole or the (4-diphenylamino)phenyl moieties associated with a -CN group attached to a double bond. The compounds are (2Z)-3-(4-(diphenylamino)-phenyl)-2-(pyridin-3-yl)prop-2-enenitrile (I), (2Z)-3-(4-(diphenylamino)phenyl)-2-(pyridin-4-yl)-prop-2-enenitrile (II) and (2Z)-3-(9-ethyl-9H-carbazol-3-yl)-2-(pyridin-2-yl)enenitrile (III). SCXRD analyses reveal that I and III crystallize in the monoclinic space groups P2/c with Z' = 2 and C2/c with Z' = 1, respectively. Compound II crystallized in the orthorhombic space group Pbcn with Z' = 1. The molecular packing analysis was conducted to examine the pyridine core effect, depending on the ortho, meta- and para-positions of the nitrogen atom, with respect to the optical properties and number of independent molecules (Z'). It is found that the double bond bearing a diphenylamino moiety introduced properties to exhibit a strong π-π-interaction in the solid state. The compounds were examined to evaluate the effects of solvent polarity, the role of the molecular structure, and the molecular interactions on their self-assembly behaviors. Compound I crystallized with a cell with two conformers, anti and syn, due to interaction with solvent. DFT calculations indicated the anti and syn structures of I are energetically stable (less than 1 eV). Also electrochemical and photophysical properties of the compounds were investigated, as well as the determination of optimization calculations in gas and different solvent (chloroform, cyclohexane, methanol, ethanol, tetrahydrofuran, dichloromethane and dimethyl sulfoxide) in the Gaussian09 program. The effect of solvent by PCM method was also investigated. The frontier HOMO and LUMO energies and gap energies are reported.

  10. 21 CFR 177.1050 - Acrylonitrile/styrene copoly-mer modified with butadiene/styrene elastomer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ..., DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as...), Food and Drug Administration, 5100 Paint Branch Pkwy., College Park, MD 20740, or available for... Paint Branch Pkwy., College Park, MD 20740, or available for inspection at the National Archives...

  11. Recycling cycle of materials applied to acrylonitrile-butadiene-styrene/policarbonate blends with styrene-butadiene-styrene copolymer addition

    NASA Astrophysics Data System (ADS)

    Cândido, L. H. A.; Ferreira, D. B.; Júnior, W. Kindlein; Demori, R.; Mauler, R. S.

    2014-05-01

    The scope of this research is the recycling of polymers from mobile phones hulls discarded and the performance evaluation when they are submitted to the Recycling Cycle of Materials (RCM). The studied material was the ABS/PC blend in a 70/30 proportion. Different compositions were evaluated adding virgin material, recycled material and using the copolymer SBS as impact modifier. In order to evaluate the properties of material's composition, the samples were characterized by TGA, FTIR, SEM, IZOD impact strength and tensile strength tests. At the first stage, the presented results suggest the composition containing 25% of recycled material and 5% of SBS combines good mechanical performance to the higher content of recycled material and lower content of impact modifier providing major benefits to recycling plans. Five cycles (RCM) were applied in the second stage; they evidenced a decrease trend considering the impact strength. At first and second cycle the impact strength was higher than reference material (ABS/PC blend) and from the fourth cycle it was lower. The superiority impact strength in the first and second cycles can be attributed to impact modifier effect. The thermal tests and the spectrometry didn't show the presence of degradation process in the material and the TGA curves demonstrated the process stability. The impact surface of each sample was observed at SEM. The microstructures are not homogeneous presenting voids and lamellar appearance, although the outer surface presents no defects, demonstrating good moldability. The present work aims to assess the life cycle of the material from the successive recycling processes.

  12. (Z)-3-(1-Methyl-1H-indol-3-yl)-2-(thiophen-3-yl)acrylonitrile.

    PubMed

    Sonar, Vijayakumar N; Parkin, Sean; Crooks, Peter A

    2004-03-01

    The title compound, C16H12N2S, has been synthesized by base-catalyzed condensation of 1-methylindole-3-carboxaldehyde with thiophene-3-acetonitrile. The product assumes an approximately planar Z configuration. The molecule has a thienyl-ring flip disorder.

  13. Effect of winding layer and speed on kenaf/glass fiber hybrid reinforced acrylonitrile butadiene styrene (ABS) composites

    NASA Astrophysics Data System (ADS)

    Khoni, Norizzahthul Ainaa Abdul; Sharifah Shahnaz S., B.; Ghazali, Che Mohd Ruzaidi

    2016-07-01

    The usage of natural fiber is becoming significant in composite industries due to their good performance. Single and continuous natural fibers have relatively high mechanical properties; especially their young modulus can be as high as glass fibers. Filament winding is a method to produce technically aligned composites which have high fibers content. The properties of filament winding can be tailored to meet the end product requirements. This research studied the compression properties of kenaf/glass fibers hybrid reinforced composites. Kenaf/glass fibers hybrid composite samples were fabricated by filament winding technique and their properties were compared with the properties of neat kenaf fiber and glass fibers composites. The kenaf/glass fiber hybrid composites exhibited higher strength compared to the neat glass fibers composites. Composites of helical pattern, which produced at low winding speed showed better compression resistance than hoop pattern winding, which produced at high winding speed. As predicted, kenaf composite showed highest water absorption; followed by kenaf/glass fiber hybrid composites while neat glass fiber has lowest water absorption capability.

  14. Conformational and Molecular Structures of α,β-Unsaturated Acrylonitrile Derivatives: Photophysical Properties and Their Frontier Orbitals.

    PubMed

    Percino, María Judith; Cerón, Margarita; Rodríguez, Oscar; Soriano-Moro, Guillermo; Castro, María Eugenia; Chapela, Víctor M; Siegler, Maxime A; Pérez-Gutiérrez, Enrique

    2016-01-01

    We report single crystal X-ray diffraction (hereafter, SCXRD) analyses of derivatives featuring the electron-donor N-ethylcarbazole or the (4-diphenylamino)phenyl moieties associated with a -CN group attached to a double bond. The compounds are (2Z)-3-(4-(diphenylamino)-phenyl)-2-(pyridin-3-yl)prop-2-enenitrile (I), (2Z)-3-(4-(diphenylamino)phenyl)-2-(pyridin-4-yl)-prop-2-enenitrile (II) and (2Z)-3-(9-ethyl-9H-carbazol-3-yl)-2-(pyridin-2-yl)enenitrile (III). SCXRD analyses reveal that I and III crystallize in the monoclinic space groups P2/c with Z' = 2 and C2/c with Z' = 1, respectively. Compound II crystallized in the orthorhombic space group Pbcn with Z' = 1. The molecular packing analysis was conducted to examine the pyridine core effect, depending on the ortho, meta- and para-positions of the nitrogen atom, with respect to the optical properties and number of independent molecules (Z'). It is found that the double bond bearing a diphenylamino moiety introduced properties to exhibit a strong π-π-interaction in the solid state. The compounds were examined to evaluate the effects of solvent polarity, the role of the molecular structure, and the molecular interactions on their self-assembly behaviors. Compound I crystallized with a cell with two conformers, anti and syn, due to interaction with solvent. DFT calculations indicated the anti and syn structures of I are energetically stable (less than 1 eV). Also electrochemical and photophysical properties of the compounds were investigated, as well as the determination of optimization calculations in gas and different solvent (chloroform, cyclohexane, methanol, ethanol, tetrahydrofuran, dichloromethane and dimethyl sulfoxide) in the Gaussian09 program. The effect of solvent by PCM method was also investigated. The frontier HOMO and LUMO energies and gap energies are reported. PMID:27043499

  15. 21 CFR 177.1050 - Acrylonitrile/styrene copoly-mer modified with butadiene/styrene elastomer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... viscosity of the matrix copolymer in butyrolactone is not less than 0.5 deciliter/gram at 35 °C, as determined by the method titled “Molecular Weight of Matrix Copolymer by Solution Viscosity,” which is... copolymer articles is not more than 11 ppm as determined by a gas chromatographic method...

  16. 21 CFR 177.1050 - Acrylonitrile/styrene copoly-mer modified with butadiene/styrene elastomer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... viscosity of the matrix copolymer in butyrolactone is not less than 0.5 deciliter/gram at 35 °C, as determined by the method titled “Molecular Weight of Matrix Copolymer by Solution Viscosity,” which is... copolymer articles is not more than 11 ppm as determined by a gas chromatographic method...

  17. 21 CFR 177.1050 - Acrylonitrile/styrene copoly-mer modified with butadiene/styrene elastomer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... viscosity of the matrix copolymer in butyrolactone is not less than 0.5 deciliter/gram at 35 °C, as determined by the method titled “Molecular Weight of Matrix Copolymer by Solution Viscosity,” which is... copolymer articles is not more than 11 ppm as determined by a gas chromatographic method...

  18. 21 CFR 177.1050 - Acrylonitrile/styrene copoly-mer modified with butadiene/styrene elastomer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... viscosity of the matrix copolymer in butyrolactone is not less than 0.5 deciliter/gram at 35 °C, as determined by the method titled “Molecular Weight of Matrix Copolymer by Solution Viscosity,” which is... copolymer articles is not more than 11 ppm as determined by a gas chromatographic method...

  19. Copper(ii) tungstate nanoflake array films: sacrificial template synthesis, hydrogen treatment, and their application as photoanodes in solar water splitting

    NASA Astrophysics Data System (ADS)

    Hu, Dianyi; Diao, Peng; Xu, Di; Xia, Mengyang; Gu, Yue; Wu, Qingyong; Li, Chao; Yang, Shubin

    2016-03-01

    We report the preparation of CuWO4 nanoflake (NF) array films by using a solid phase reaction method in which WO3 NFs were employed as sacrificial templates. The SEM, TEM and XRD results demonstrated that the obtained CuWO4 films possessed a network structure that was composed of single crystalline NFs intersected with each other. The CuWO4 NF films showed superior photoelectrochemical (PEC) activity to other CuWO4 photoanodes reported recently for the oxygen evolution reaction (OER). We attributed the high activity to the unique morphological and crystalline structure of the CuWO4 film, which enhanced the photoactivity by providing a large specific area, a short hole transport distance from the inside of CuWO4 to the CuWO4/solution interface, and a low grain boundary density. Hydrogen treatment by annealing the CuWO4 NF film in mixed gases of H2 and Ar could further enhance the photoactivity, as hydrogen treatment significantly increased the electron density of CuWO4 by generating oxygen vacancy in the lattice. The photocurrent density for OER obtained on the hydrogen-treated (H-treated) CuWO4 NF film is the largest ever reported on CuWO4 photoanodes in the literature. Moreover, the CuWO4 photoanodes exhibit good stability in weak alkaline solution, while the H-treated CuWO4 photoanodes exhibit acceptable stability. This work not only reveals the potential of CuWO4 as a photoanode material for solar water splitting but also shows that the construction of nanostructured CuWO4 photoanodes is a promising method to achieve high PEC activity toward OER.We report the preparation of CuWO4 nanoflake (NF) array films by using a solid phase reaction method in which WO3 NFs were employed as sacrificial templates. The SEM, TEM and XRD results demonstrated that the obtained CuWO4 films possessed a network structure that was composed of single crystalline NFs intersected with each other. The CuWO4 NF films showed superior photoelectrochemical (PEC) activity to other CuWO4 photoanodes reported recently for the oxygen evolution reaction (OER). We attributed the high activity to the unique morphological and crystalline structure of the CuWO4 film, which enhanced the photoactivity by providing a large specific area, a short hole transport distance from the inside of CuWO4 to the CuWO4/solution interface, and a low grain boundary density. Hydrogen treatment by annealing the CuWO4 NF film in mixed gases of H2 and Ar could further enhance the photoactivity, as hydrogen treatment significantly increased the electron density of CuWO4 by generating oxygen vacancy in the lattice. The photocurrent density for OER obtained on the hydrogen-treated (H-treated) CuWO4 NF film is the largest ever reported on CuWO4 photoanodes in the literature. Moreover, the CuWO4 photoanodes exhibit good stability in weak alkaline solution, while the H-treated CuWO4 photoanodes exhibit acceptable stability. This work not only reveals the potential of CuWO4 as a photoanode material for solar water splitting but also shows that the construction of nanostructured CuWO4 photoanodes is a promising method to achieve high PEC activity toward OER. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr09210h

  20. High-resolution measurement and mapping of tungstate in waters, soils and sediments using the low-disturbance DGT sampling technique.

    PubMed

    Guan, Dong-Xing; Williams, Paul N; Xu, Hua-Cheng; Li, Gang; Luo, Jun; Ma, Lena Q

    2016-10-01

    Increasing tungsten (W) use for industrial and military applications has resulted in greater W discharge into natural waters, soils and sediments. Risk modeling of W transport and fate in the environment relies on measurement of the release/mobilization flux of W in the bulk media and the interfaces between matrix compartments. Diffusive gradients in thin-films (DGT) is a promising passive sampling technique to acquire such information. DGT devices equipped with the newly developed high-resolution binding gels (precipitated zirconia, PZ, or ferrihydrite, PF, gels) or classic/conventional ferrihydrite slurry gel were comprehensively assessed for measuring W in waters. (Ferrihydrite)DGT can measure W at various ionic strengths (0.001-0.5molL(-1) NaNO3) and pH (4-8), while (PZ)DGT can operate across slightly wider environmental conditions. The three DGT configurations gave comparable results for soil W measurement, showing that typically W resupply is relatively poorly sustained. 1D and 2D high-resolution W profiling across sediment-water and hotspot-bulk media interfaces from Lake Taihu were obtained using (PZ)DGT coupled with laser ablation ICP-MS measurement, and the apparent diffusion fluxes across the interfaces were calculated using a numerical model. PMID:27209520

  1. Poly (vinylidene fluoride) / Poly (acrylonitrile)–based Superior Hydrophobic Piezoelectric Solid Derived by Aligned Carbon Nanotube in Electrospinning: Fabrication, the Phase Conversion and Surface Energy

    PubMed Central

    Aqeel, Salem M.; Than, Lisa; Sreenivasulu, Gollapudi

    2015-01-01

    Multifunctional materials have attracted many interests from both fundamental and practical aspects, such as field–effect transistor, electric protection, transducers and biosensor. Here we demonstrated the first superior hydrophobic piezoelectric surface based on the polymer blend of polyvinylidene fluoride (PVDF)–polyacrilonitrile (PAN) assisted with functionalized multiwalled nanotubes (MWNTs), by a modified electrospinning method. Typically the β–phase polyvinylidene fluoride (PVDF) was considered as the excellent piezoelectric and pyroelectric materials. However, polar β–phase of PVDF exhibited a natural high hydrophilicity. As a well–known fact, the wettability of the surface is dominated by two major factors: surface composition and surface roughness. The significant conversions derived by the incorporation of MWNTs, from nonpolar α–phase to highly polar β–phase of PVDF, were confirmed by FTIR. Meanwhile, the effects of MWNTs on the improvement of the roughness and the hydrophobicity of polymer blend were evaluated by atomic force microscopy (AFM) and contact angle (CA). Molar free energy of wetting of the polymer nanocomposite decreases with increasing the wt.% of MWNTs. All molar free energy of wetting of PVDF–PAN/MWNTs were negative, which means the non–wettability of film. The combination of surface roughness and low–surface–energy modification in nanostructured composites leads to high hydrophobicity. Particularly, fabrication of superior hydrophobic surfaces not only has fundamental interest but also various possible functional applications in micro– and nano–materials and devices. PMID:26989486

  2. 23Na magic-angle spinning nuclear magnetic resonance of central and satellite transitions in the characterization of the anhydrous, dihydrate, and mixed phases of sodium molybdate and tungstate.

    PubMed

    Skibsted, J; Jakobsen, H J

    1994-02-01

    23Na Magic-angle spinning nuclear magnetic resonance (MAS NMR) spectra of pure phases for Na2MoO4, Na2MoO4 x 2H2O, Na2WO4, and Na2WO4 x 2H2O have led to the determination of accurate values for the quadrupole coupling parameters and isotropic chemical shifts for all Na sites. The analysis of the spectra involves a combination of simulations of the line shapes for the central transitions and the manifold of spinning sidebands for the satellite transitions. The spectral parameters for the pure phases represent a prerequisite for a correct assignment and quantitative evaluation of 23Na MAS spectra at different magnetic field strengths observed for mixtures of the anhydrous and dihydrate phases. Such phase mixtures are observed, for example, for some commercial samples of Na2MoO4 or may be generated by (i) exposure of the anhydrous phases to a humid atmosphere or (ii) gently heating the dihydrates. The quadrupole coupling parameters for the two Na sites in the dihydrates are tentatively assigned to the two crystallographically distinct Na atoms in the asymmetric unit by calculations of an approximate dependency of the electric field gradient tensor on the local geometry for the Na sites.

  3. Study of two tungstates Ca0.5 Cd0.5 WO4 and Ca0.2 Cd0.8 WO4 by transmission electron microscopy.

    PubMed

    Taoufyq, A; Patout, L; Guinneton, F; Benlhachemi, A; Bakiz, B; Villain, S; Lyoussi, A; Nolibe, G; Gavarri, J-R

    2015-01-01

    To better understand the role of crystal structures and local disorder in the photonic properties of the system (1 - x)CaWO4  - xCdWO4 with 0 < x < 1, two specific phases with compositions x = 0.5 (scheelite phase) and 0.8 (wolframite phase) have been studied by scanning and transmission electron microscopies. High-resolution electron microscopy images and image simulations, associated with X-ray diffraction data, allowed confirming the lattices and space groups I41 /a and P2/c of the two scheelite and wolframite phases, at the local scale. The electron microscopy data show the existence of a high degree of crystallization associated with statistical distribution of Ca or Cd atoms on a Ca1- x Cdx site in each lattice. PMID:26372831

  4. Ethyl-enedi-ammonium sodium tetra-kis-[bis-(ethyl-enedi-amine-κ(2) N,N')(oxalato-κ(2) O (1),O (2))cobalt(III)] [penta-hydrogen di(phosphato-octa-deca-tungstate)] tetra-deca-hydrate.

    PubMed

    Zhang, Shuzhuo; Wang, Jing; Xu, Yun

    2013-10-16

    The title compound, Na(C2H10N2)[Co(C2O4)(C2H8N2)2]4[H5(P2W18O62)2]·14H2O, prepared under hydro-thermal conditions, consists of two Dawson-type [P2W18O62](6-) anions, four isolated [Co(en)2(ox)](+) cations (en = ethyl-enedi-amine and ox = oxalate), one Na(+) cation, one [H2en](2+) cation, and a number of ordered (14) and disordered solvent water mol-ecules. The [P2W18O62](6-) polyoxidometalate anion has site symmetry 1 and contains two structurally distinct types of W atoms: viz. six W atoms on vertical pseudo-mirror planes grouped in two sets of three, and 12 equatorial W atoms that do not lie in the pseudo-mirror planes grouped in two sets of six. In each [Co(en)2(ox)](+) cation, the Co(III) ion is coordinated by four N atoms from two en ligands and two O atoms from the ox ligands, completing a distorted octa-hedral structure. The sodium cation lies on an inversion centre and additionally links the complex cations and anions. In the crystal, the various units are linked by N-H⋯O and O-H⋯O hydrogen bonds, which together with C-H⋯O hydrogen bonds form a three-dimensional structure. The contribution of a region of disordered electron density, possibly highly disordered solvent water mol-ecules, to the scattering was removed with the SQUEEZE option of PLATON [Spek (2009 ▶). Acta Cryst. D65, 148-155]. To equilibrate the charges five H(+) ions have been added to the polyoxidometalate. These H(+) ions and the disordered solvent contribution were not included in the reported mol-ecular weight and density. PMID:24454036

  5. 40 CFR Table 7 to Subpart Vvvvvv... - Partially Soluble HAP

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    .... Acrolein 107028 15. Acrylonitrile 107131 16. Allyl chloride 107051 17. Benzene 71432 18. Benzyl chloride.... Tetrachloroethylene (per- chloroethylene) 127184 51. Tetrachloromethane (carbon tetrachloride) 56235 52....

  6. 24 CFR Appendix I to Subpart C of... - Specific Hazardous Substances

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    .... Hazardous Liquids Acetic Acid Acetic Anhydride Acetone Acrylonitrile Amyl Acetate Amyl Alcohol Benzene Butyl... Butane Ethene Ethylene Ethylene Oxide Hydrogen Liquefied Natural Gas (LNG) Liquefied Petroleum Gas...

  7. 24 CFR Appendix I to Subpart C of... - Specific Hazardous Substances

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    .... Hazardous Liquids Acetic Acid Acetic Anhydride Acetone Acrylonitrile Amyl Acetate Amyl Alcohol Benzene Butyl... Butane Ethene Ethylene Ethylene Oxide Hydrogen Liquefied Natural Gas (LNG) Liquefied Petroleum Gas...

  8. Melt processing and property testing of a model system of plastics contained in waste from electrical and electronic equipment.

    PubMed

    Triantou, Marianna I; Tarantili, Petroula A; Andreopoulos, Andreas G

    2015-05-01

    In the present research, blending of polymers used in electrical and electronic equipment, i.e. acrylonitrile-butadiene-styrene terpolymer, polycarbonate and polypropylene, was performed in a twin-screw extruder, in order to explore the effect process parameters on the mixture properties, in an attempt to determine some characteristics of a fast and economical procedure for waste management. The addition of polycarbonate in acrylonitrile-butadiene-styrene terpolymer seemed to increase its thermal stability. Also, the addition of polypropylene in acrylonitrile-butadiene-styrene terpolymer facilitates its melt processing, whereas the addition of acrylonitrile-butadiene-styrene terpolymer in polypropylene improves its mechanical performance. Moreover, the upgrading of the above blends by incorporating 2 phr organically modified montmorillonite was investigated. The prepared nanocomposites exhibit greater tensile strength, elastic modulus and storage modulus, as well as higher melt viscosity, compared with the unreinforced blends. The incorporation of montmorillonite nanoplatelets in polycarbonate-rich acrylonitrile-butadiene-styrene terpolymer/polycarbonate blends turns the thermal degradation mechanism into a two-stage process. Alternatively to mechanical recycling, the energy recovery from the combustion of acrylonitrile-butadiene-styrene terpolymer/polycarbonate and acrylonitrile-butadiene-styrene terpolymer/polypropylene blends was recorded by measuring the gross calorific value. Comparing the investigated polymers, polypropylene presents the higher gross calorific value, followed by acrylonitrile-butadiene-styrene terpolymer and then polycarbonate. The above study allows a rough comparative evaluation of various methodologies for treating plastics from waste from electrical and electronic equipment.

  9. 40 CFR 63.1103 - Source category-specific applicability, definitions, and requirements.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Enclosure” in 40 CFR 52.741, appendix B. (iii) The enclosure may have permanent or temporary openings to... acrylonitrile emission rate determination. For an owner or operator electing to comply with paragraph (b)(3)(ii) of this section, the facility acrylonitrile emission rate must be determined using the...

  10. 40 CFR 68.130 - List of substances.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... name CAS No. Threshold quantity (lbs) Basis for listing Acrolein 107-02-8 5,000 b Acrylonitrile 107-13... Acrolein 5,000 b 107-11-9 Allylamine 10,000 b 107-12-0 Propionitrile 10,000 b 107-13-1 Acrylonitrile...

  11. 40 CFR 68.130 - List of substances.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... name CAS No. Threshold quantity (lbs) Basis for listing Acrolein 107-02-8 5,000 b Acrylonitrile 107-13... Acrolein 5,000 b 107-11-9 Allylamine 10,000 b 107-12-0 Propionitrile 10,000 b 107-13-1 Acrylonitrile...

  12. 40 CFR 68.130 - List of substances.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... name CAS No. Threshold quantity (lbs) Basis for listing Acrolein 107-02-8 5,000 b Acrylonitrile 107-13... Acrolein 5,000 b 107-11-9 Allylamine 10,000 b 107-12-0 Propionitrile 10,000 b 107-13-1 Acrylonitrile...

  13. Multiple reuses of Rhodococcus ruber TH3 free cells to produce acrylamide in a membrane dispersion microreactor.

    PubMed

    Li, Jiahui; Liu, Junqi; Chen, Jie; Wang, Yujun; Luo, Guangsheng; Yu, Huimin

    2015-01-01

    In this work, multiple reuses of Rhodococcus ruber TH3 free cells for the hydration of acrylonitrile to produce acrylamide in a membrane dispersion microreactor were carried out. Through using a centrifuge, the reactions reached 39.9, 39.5, 38.6 and 38.0wt% of the final acrylamide product concentration respectively within 35min in a four cycle reuse of free cells. In contrast, using a stirring tank, free cells could only be used once with the same addition speed of acrylonitrile with a microreactor. Through observing the dissolution behavior of acrylonitrile microdroplets in a free cell solution using a coaxial microfluidic device and microscope, it was found that the acrylonitrile microdroplets with a diameter of 75μm were rarely observed within a length of 2cm channel within 10s, which illustrated that the microreactor can intensify the reaction rate to reduce the inhibition of acrylonitrile and acrylamide.

  14. UV-VUV synchrotron radiation spectroscopy of NiWO4

    NASA Astrophysics Data System (ADS)

    Kuzmin, A.; Pankratov, V.; Kalinko, A.; Kotlov, A.; Shirmane, L.; Popov, A. I.

    2016-07-01

    Photoluminescence and excitation spectra of microcrystalline and nanocrystalline nickel tungstate (NiWO4) were measured using UV-VUV synchrotron radiation source. The origin of the bands is interpreted using comparative analysis with isostructural ZnWO4 tungstate and based on the results of recent first-principles band structure calculations. The influence of the local atomic structure relaxation and of Ni2+ intra-ion d-d transitions on the photoluminescence band intensity are discussed.

  15. Road asphalt modifiers based on oil-resistant rubbers and products of thermal transformations of coals

    SciTech Connect

    Sharypov, V.I.; Kiselev, V.P.; Beregovtsova, N.G.; Bugaenko, M.B.; Kuznetsov, B.N.

    2008-07-15

    The properties of asphalt binder modifiers prepared by dissolving butadiene-acrylonitrile rubbers and their production waste in liquid products of heat treatment of various brands of coal were studied.

  16. Phosphonic acid based ion exchange resins

    DOEpatents

    Horwitz, E.P.; Alexandratos, S.D.; Gatrone, R.C.; Chiarizia, R.

    1994-01-25

    An ion exchange resin is described for extracting metal ions from a liquid waste stream. An ion exchange resin is prepared by copolymerizing a vinylidene diphosphonic acid with styrene, acrylonitrile and divinylbenzene. 9 figures.

  17. MW-assisted synthesis of carboxymethyl tamarind kernel polysaccharide-g-polyacrylonitrile: optimization and characterization.

    PubMed

    Meenkashi; Ahuja, Munish; Verma, Purnima

    2014-11-26

    Microwave-assisted synthesis of graft copolymer of carboxymethyl tamarind seed polysaccharide and polyacrylonitrile was carried out. The effect of formulation and process variables on grafting efficiency of carboxymethyl tamarind kernel polysaccharide-g-poly(acrylonitrile) was studied using response surface methodology. The results revealed that the significant factors affecting grafting efficiency were concentrations of ammonium persulphate, acrylonitrile and interaction effects of ammonium persulphate and acrylonitrile concentrations. The optimal calculated parameters were found to be microwave exposure time-99.48 s, microwave exposure power-160 W, concentration of acrylonitrile-0.10% (w/v), concentration of ammonium persulphate--40 mmol/l, which provided graft copolymer with grafting efficiency of 96%. The formation of graft copolymer was confirmed by FT-IR studies and validated by scanning electron micrographs. Thermogravimetric analysis indicated higher thermal stability of graft copolymer and X-ray diffraction study revealed increase in crystallinity on graft polymerization. Further, the graft copolymer showed pH dependant swelling.

  18. Phosphonic acid based exchange resins

    DOEpatents

    Horwitz, E.P.; Alexandratos, S.D.; Gatrone, R.C.; Chiarizia, R.

    1995-09-12

    An ion exchange resin is described for extracting metal ions from a liquid waste stream. An ion exchange resin is prepared by copolymerizing a vinylidene diphosphonic acid with styrene, acrylonitrile and divinylbenzene. 10 figs.

  19. Phosphonic acid based ion exchange resins

    DOEpatents

    Horwitz, E.P.; Alexandratos, S.D.; Gatrone, R.C.; Chiarizia, R.

    1996-07-23

    An ion exchange resin is described for extracting metal ions from a liquid waste stream. An ion exchange resin is prepared by copolymerizing a vinylidene diphosphonic acid with styrene, acrylonitrile and divinylbenzene. 10 figs.

  20. Recycling of engineering plastics from waste electrical and electronic equipments: influence of virgin polycarbonate and impact modifier on the final performance of blends.

    PubMed

    Ramesh, V; Biswal, Manoranjan; Mohanty, Smita; Nayak, Sanjay K

    2014-05-01

    This study is focused on the recovery and recycling of plastics waste, primarily polycarbonate, poly(acrylonitrile-butadiene-styrene) and high impact polystyrene, from end-of-life waste electrical and electronic equipments. Recycling of used polycarbonate, acrylonitrile-butadiene-styrene, polycarbonate/acrylonitrile-butadiene-styrene and acrylonitrile-butadiene-styrene/high impact polystrene material was carried out using material recycling through a melt blending process. An optimized blend composition was formulated to achieve desired properties from different plastics present in the waste electrical and electronic equipments. The toughness of blended plastics was improved with the addition of 10 wt% of virgin polycarbonate and impact modifier (ethylene-acrylic ester-glycidyl methacrylate). The mechanical, thermal, dynamic-mechanical and morphological properties of recycled blend were investigated. Improved properties of blended plastics indicate better miscibility in the presence of a compatibilizer suitable for high-end application. PMID:24695435

  1. 21 CFR 175.365 - Vinylidene chloride copolymer coatings for polycarbonate film.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... or both sides of a base film produced from polycarbonate resins complying with § 177.1580 of this... vinylidene chloride with acrylonitrile, methyl acrylate, and acrylic acid. The finished copolymers contain...

  2. 21 CFR 175.365 - Vinylidene chloride copolymer coatings for polycarbonate film.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... or both sides of a base film produced from polycarbonate resins complying with § 177.1580 of this... vinylidene chloride with acrylonitrile, methyl acrylate, and acrylic acid. The finished copolymers contain...

  3. 21 CFR 175.365 - Vinylidene chloride copolymer coatings for polycarbonate film.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... or both sides of a base film produced from polycarbonate resins complying with § 177.1580 of this... vinylidene chloride with acrylonitrile, methyl acrylate, and acrylic acid. The finished copolymers contain...

  4. Poly(N-cyanoethylethyleneimine): a new nanoscale template for biomimetic silicification.

    PubMed

    Noda, Daisuke; Arai, Yoshiaki; Souma, Daiki; Nagashima, Hideo; Jin, Ren-Hua

    2014-09-25

    Poly(N-cyanoethylethyleneimine) (PCEI) obtained by Michael addition of linear poly(ethyleneimine) (LPEI) with acrylonitrile provided novel nanocrystalline entities which could serve as catalytic templates affording nanosheet-based structured silica under mild conditions.

  5. Phosphonic acid based exchange resins

    DOEpatents

    Horwitz, E. Philip; Alexandratos, Spiro D.; Gatrone, Ralph C.; Chiarizia, Ronato

    1995-01-01

    An ion exchange resin for extracting metal ions from a liquid waste stream. An ion exchange resin is prepared by copolymerizing a vinylidene diphosphonic acid with styrene, acrylonitrile and divinylbenzene.

  6. Phosphonic acid based ion exchange resins

    DOEpatents

    Horwitz, E. Philip; Alexandratos, Spiro D.; Gatrone, Ralph C.; Chiarizia, Ronato

    1994-01-01

    An ion exchange resin for extracting metal ions from a liquid waste stream. An ion exchange resin is prepared by copolymerizing a vinylidene disphosphonic acid with styrene, acrylonitrile and divinylbenzene.

  7. Phosphonic acid based ion exchange resins

    DOEpatents

    Horwitz, E. Philip; Alexandratos, Spiro D.; Gatrone, Ralph C.; Chiarizia, Ronato

    1996-01-01

    An ion exchange resin for extracting metal ions from a liquid waste stream. An ion exchange resin is prepared by copolymerizing a vinylidene diphosphonic acid with styrene, acrylonitrile and divinylbenzene.

  8. Recycling of engineering plastics from waste electrical and electronic equipments: influence of virgin polycarbonate and impact modifier on the final performance of blends.

    PubMed

    Ramesh, V; Biswal, Manoranjan; Mohanty, Smita; Nayak, Sanjay K

    2014-05-01

    This study is focused on the recovery and recycling of plastics waste, primarily polycarbonate, poly(acrylonitrile-butadiene-styrene) and high impact polystyrene, from end-of-life waste electrical and electronic equipments. Recycling of used polycarbonate, acrylonitrile-butadiene-styrene, polycarbonate/acrylonitrile-butadiene-styrene and acrylonitrile-butadiene-styrene/high impact polystrene material was carried out using material recycling through a melt blending process. An optimized blend composition was formulated to achieve desired properties from different plastics present in the waste electrical and electronic equipments. The toughness of blended plastics was improved with the addition of 10 wt% of virgin polycarbonate and impact modifier (ethylene-acrylic ester-glycidyl methacrylate). The mechanical, thermal, dynamic-mechanical and morphological properties of recycled blend were investigated. Improved properties of blended plastics indicate better miscibility in the presence of a compatibilizer suitable for high-end application.

  9. Uniformly microsized luminescent materials obtained through a solid state reaction of WO{sub 3} with Ln{sup 3+}-exchanged zeolite L at 700 °C

    SciTech Connect

    Wang, Yige; Fang, Yi; Zhang, Wenjun; Zhang, Li; Chen, Yuhuan; Yu, Xiaoyan

    2013-06-01

    Graphical abstract: We have reported the modification of Ln3+/ZL microcrystals by the tungstate-oxygen species via a solid state reaction of WO{sub 3} and Ln{sup 3+}-exchanged zeolite L at 700 °C. Highlights: ► Luminescent materials were obtained from zeolite L crystals. ► The materials show characteristic luminescence of Eu{sup 3+} and Tb{sup 3+} ions. ► The framework of zeolite L crystals has been kept during the annealing process. ► Energy transfer from tungstate-oxygen species to lanthanide was confirmed. - Abstract: In this work, we report the uniformly microsized luminescent materials prepared by a solid state reaction of WO{sub 3} and Ln{sup 3+}-exchanged zeolite L at 700 °C. The obtained materials were investigated by SEM, XRD and photoluminescence spectroscopy. The influence of tungstate-oxygen species on the morphology and luminescence of the materials were discussed in detail. Energy transfer from the tungstate-oxygen species to Eu{sup 3+} and Tb{sup 3+} ions have been demonstrated by the photoluminescence spectra, implying the loading of tungstate-oxygen species into the nanochannels of the crystals and the close proximity of which to Eu{sup 3+} ions.

  10. Anthocyanins facilitate tungsten accumulation in Brassica

    SciTech Connect

    Hale, K.L.

    2002-11-01

    Accumulation of molybdenum in Brassica was recently found to be correlated with anthocyanin content, involving the formation of a blue complex. Here the role of anthocyanins in tungsten sequestration was investigated using three species of Brassica: B. rapa (cv. Fast plants), B. juncea (Indian mustard) and B. oleracea (red cabbage). Seedlings of B. rapa and B. juncea turned blue when supplied with colourless tungstate. The blue compound co-localized with anthocyanins in the peripheral cell layers, and the degree of blueness was correlated with anthocyanin content. The direct involvement of anthocyanins in the blue coloration was evident when purified anthocyanins showed a colour change from pink to blue in vitro upon addition of tungstate, over a wide pH range. Anthocyanin production was upregulated 3-fold by W in B. juncea, possibly reflecting a function for anthocyanins in W tolerance or sequestration. The presence of anthocyanins facilitated W accumulation in B. rapa: anthocyanin-containing seedlings accumulated 3-fold more W than an anthocyaninless mutant. There was no correlation between anthocyanin content and W tolerance under these conditions. The nature of the interaction between anthocyanins and tungstate was investigated. X-ray absorption spectroscopy showed no change in the local chemical environment of Wupon uptake of tungstate by the plant; HPLC analysis of purified anthocyanin with or without tungstate showed no peak shift after metal treatment.

  11. Classification of a Haemophilus influenzae ABC Transporter HI1470/71 through Its Cognate Molybdate Periplasmic Binding Protein, MolA

    SciTech Connect

    Tirado-Lee, Leidamarie; Lee, Allen; Rees, Douglas C.; Pinkett, Heather W.

    2014-10-02

    molA (HI1472) from H. influenzae encodes a periplasmic binding protein (PBP) that delivers substrate to the ABC transporter MolB{sub 2}C{sub 2} (formerly HI1470/71). The structures of MolA with molybdate and tungstate in the binding pocket were solved to 1.6 and 1.7 {angstrom} resolution, respectively. The MolA-binding protein binds molybdate and tungstate, but not other oxyanions such as sulfate and phosphate, making it the first class III molybdate-binding protein structurally solved. The {approx}100 {mu}M binding affinity for tungstate and molybdate is significantly lower than observed for the class II ModA molybdate-binding proteins that have nanomolar to low micromolar affinity for molybdate. The presence of two molybdate loci in H. influenzae suggests multiple transport systems for one substrate, with molABC constituting a low-affinity molybdate locus.

  12. Development of a new electrolyte matrix for MCFC

    SciTech Connect

    Nagashima, I.; Higaki, K.; Terada, S.; Suemitsu, T.

    1996-12-31

    To prolong the life of cell is one of the most important issues for MCFC to be brought into actual application. In this respect, investigators have been proposing the addition of tungstate salt such as K2WO4 into MCFC electrolyte, which is supposed effectively to reduce the sintering of anode probably by precipitates formed through the reduction of tungstate with dissolved hydrogen near the anode surface. In this research, such effect upon sintering of anode was quantitatively examined by out-of-cell tests and the validity of above assumption for the mechanism was confirmed. Also other effects of tungstate salt addition into electrolyte, such upon corrosion of separator, solubility of cathode, stability of matrix substrates (LiAlO{sub 2}) were investigated.

  13. Research study for gel precursors as glass and ceramic starting materials for space processing applications research

    NASA Technical Reports Server (NTRS)

    Downs, R. L.; Miller, W. J.

    1983-01-01

    The development of techniques for the preparation of glass and ceramic starting materials that will result in homogeneous glasses or ceramic products when melted and cooled in a containerless environment is described. Metal-organic starting materials were used to make compounds or mixtures which were then decomposed by hydrolysis reactions to the corresponding oxides. The sodium tungstate system was chosen as a model for a glass with a relatively low melting temperature. The alkoxide tungstates also have interesting optical properties. For all the compositions studied, comparison samples were prepared from inorganic starting materials and submitted to the same analyses.

  14. Polyoxometalates for radioactive waste treatment. Annual progress report, June 15, 1996--September 30, 1997

    SciTech Connect

    Pope, M.T.

    1997-01-01

    'Four areas of research have been investigated during the first year of this project: (1) Selective separations of Ln{sup 3+} and An{sup 4+}; (2) Very large tungstate complexes of Ln{sup 3+}; (3) U{sup 4+} and UO{sub 2}{sup 2+} polytungstate complexes; (4) Rhenium (technetium) polyoxometalates. Progress in each of these areas is summarized.'

  15. Molybdenum Incorporation in Tungsten Aldehyde Oxidoreductase Enzymes from Pyrococcus furiosus▿ †

    PubMed Central

    Sevcenco, Ana-Maria; Bevers, Loes E.; Pinkse, Martijn W. H.; Krijger, Gerard C.; Wolterbeek, Hubert T.; Verhaert, Peter D. E. M.; Hagen, Wilfred R.; Hagedoorn, Peter-Leon

    2010-01-01

    The hyperthermophilic archaeon Pyrococcus furiosus expresses five aldehyde oxidoreductase (AOR) enzymes, all containing a tungsto-bispterin cofactor. The growth of this organism is fully dependent on the presence of tungsten in the growth medium. Previous studies have suggested that molybdenum is not incorporated in the active site of these enzymes. Application of the radioisotope 99Mo in metal isotope native radioautography in gel electrophoresis (MIRAGE) technology to P. furiosus shows that molybdenum can in fact be incorporated in all five AOR enzymes. Mo(V) signals characteristic for molybdopterin were observed in formaldehyde oxidoreductase (FOR) in electron paramagnetic resonance (EPR)-monitored redox titrations. Our finding that the aldehyde oxidation activity of FOR and WOR5 (W-containing oxidoreductase 5) correlates only with the residual tungsten content suggests that the Mo-containing AORs are most likely inactive. An observed W/Mo antagonism is indicative of tungstate-dependent negative feedback of the expression of the tungstate/molybdate ABC transporter. An intracellular selection mechanism for tungstate and molybdate processing has to be present, since tungsten was found to be preferentially incorporated into the AORs even under conditions with comparable intracellular concentrations of tungstate and molybdate. Under the employed growth conditions of starch as the main carbon source in a rich medium, no tungsten- and/or molybdenum-associated proteins are detected in P. furiosus other than the high-affinity transporter, the proteins of the metallopterin insertion machinery, and the five W-AORs. PMID:20562313

  16. An Inexpensive Device for Studying Electrochromism

    ERIC Educational Resources Information Center

    Ibanez, Jorge G.; Puente-Caballero, Rodrigo; Torres-Perez, Jonatan; Bustos, Daniel; Carmona-Orbezo, Aranzazu; Sevilla, Fortunato B., III

    2012-01-01

    A novel procedure for the preparation of electrochromic WO[subscript 3] films from readily available materials is presented. It is based on the electrochemical preparation of potassium tungstate from tungsten filaments of incandescent light bulbs in a potassium hydroxide solution. Tungstic acid is then produced by proton exchange using a…

  17. Particle-matrix interfacial bonding: Effect on the fracture properties of rubber-modified epoxy polymers

    SciTech Connect

    Huang, Y.; Kinloch, A.J.; Bertsch, R.J.; Siebert, A.R.

    1993-12-31

    This study employed various butadiene-acrylonitrile rubbers and showed that both the functionality of the end groups and the acrylonitrile content have a strong influence on the microstructure and the interfacial bonding that are observed in the resulting rubber-toughened epoxy. For the rubbers examined, significant toughening is recorded only when the rubber forms a separate phase in the epoxy matrix with a particle size on the order of micrometers. These microstructural features are affected by both the functionality of the end groups and the acrylonitrile content of the rubber employed. However, once phase separation of the rubber has been achieved to give particles on the order of micrometers in size, then the interfacial bonding between the rubber particles and the epoxy matrix has only a small effect on the fracture properties of the rubber-toughened epoxy polymers. 28 refs., 6 figs., 3 tabs.

  18. Electrically Conducting Polymer-Copper Sulphide Composite Films, Preparation by Treatment of Polymer-Copper (2) Acetate Composites with Hydrogen Sulfide

    NASA Technical Reports Server (NTRS)

    Yamamoto, Takakazu; Kamigaki, Takahira; Kubota, Etsuo

    1988-01-01

    Polymer copper sulfide composite films were prepared by treatment of polymer poly(vinyl chloride), poly(acrylonitrile), copolymer of vinyl chloride and vinyl acetate (90:10), and ABS resin copper (2) acetate composites with hydrogen sulfide. The films showed electrical conductivity higher than 0.015 S/cm when they contained more than 20 wt percent of copper sulfide. A poly(acrylonitrile)-copper sulfide composite film containing 40 to 50 wt percent of copper sulfide showed electrical conductivity of 10 to 150.0 S/cm and had relatively high mechanical strength to be used in practical purposes.

  19. Low pour crude oil compositions

    SciTech Connect

    Motz, K.L.; Latham, R.A.; Statz, R.J.

    1990-05-22

    This patent describes and improvement in the process of transporting waxy crude oils through a pipeline. It comprises: incorporating into the crude oil an effective pour point depressant amount of an additive comprising a polymer selected from the group consisting of copolymers of ethylene and acrylonitrile, and terpolymers of ethylene, acrylonitrile and a third monomer selected from the group consisting of vinyl acetate, carbon monoxide, alkyl acrylates, alkyl methacrylates, alkyl vinyl ethers, vinyl chloride, vinyl fluoride, acrylic acid, and methacrylic acid, wherein the amount of third monomer in the terpolymer ranges from about 0.1 to about 10.0 percent by weight.

  20. Effect of heating rate on toxicity of pyrolysis gases from some elastomers

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Kosola, K. L.; Solis, A. N.

    1977-01-01

    The effect of heating rate on the toxicity of the pyrolysis gases from six elastomers was investigated, using a screening test method. The elastomers were polyisoprene (natural rubber), styrene-butadiene rubber (SBR), ethylene propylene diene terpolymer (EPDM), acrylonitrile rubber, chlorosulfonated polyethylene rubber, and polychloroprene. The rising temperature and fixed temperature programs produced exactly the same rank order of materials based on time to death. Acrylonitrile rubber exhibited the greatest toxicity under these test conditions, and carbon monoxide was not found in sufficient concentrations to be the primary cause of death.

  1. Morphology of a silver/polyacrylonitrile nanocomposite

    NASA Astrophysics Data System (ADS)

    Kudryashov, M. A.; Mashin, A. I.; Tyurin, A. S.; Fedosov, A. E.; Chidichimo, G.; De Filpo, G.

    2011-01-01

    Silver/polyacrylonitrile (Ag/PAN) nanocomposites are synthesized at the stage of simultaneous acrylonitrile polymerization and the reduction of silver ions from a mixture of silver nitrate AgNO3, acrylonitrile, and a photoinitiator. The synthesized films are transparent in the visible region and are characterized by a uniform dispersion of silver nanoparticles in a PAN matrix without any macroscopic agglomeration. The effects of the metal salt and photoinitiator concentrations on the size and density of metal nanoparticles in a composite are revealed.

  2. Preparation and photoelectrocatalytic activity of a nano-structured WO{sub 3} platelet film

    SciTech Connect

    Yagi, Masayuki Maruyama, Syou; Sone, Koji; Nagai, Keiji; Norimatsu, Takayoshi

    2008-01-15

    A tungsten trioxide (WO{sub 3}) film was prepared by calcination from a precursor paste including suspended ammonium tungstate and polyethylene glycol (PEG). The ammonium tungstate suspension was yielded by an acid-base reaction of tungstic acid and an ammonium solution followed by deposition with ethanol addition. Thermogravimetric (TG) analysis showed that the TG profile of PEG is significantly influenced by deposited ammonium tungstate, suggesting that PEG is interacting strongly with deposited ammonium tungstate in the suspension paste. X-ray diffraction (XRD) data indicated that the WO{sub 3} film is crystallized by sintering over 400 deg. C. The scanning electron microscopic (SEM) measurement showed that the film is composed of the nano-structured WO{sub 3} platelets. The semiconductor properties of the film were examined by Mott-Schottky analysis to give flat band potential E{sub FB}=0.30 V vs. saturated calomel reference electrode (SCE) and donor carrier density N{sub D}=2.5x10{sup 22} cm{sup -3}, latter of which is higher than previous WO{sub 3} films by two orders of magnitude. The higher N{sub D} was explained by the large interfacial heterojunction area caused by the nano-platelet structure, which apparently increases capacitance per a unit electrode area. The WO{sub 3} film sintered at 550 deg. C produced 3.7 mA cm{sup -2} of a photoanodic current at 1.2 V vs. SCE under illumination with a 500 W xenon lamp due to catalytic water oxidation. This photocurrent was 4.5-12.8 times higher than those for the other control WO{sub 3} films prepared by similar but different procedures. The high catalytic activity could be explained by the nano-platelet structure. The photocurrent was generated on illumination of UV and visible light below 470 nm, and the maximum incident photon-to-current conversion efficiency (IPCE) was 47% at 320 nm at 1.2 V. Technically important procedures for preparation of nano-structured platelets were discussed. - Graphical abstract: A

  3. 40 CFR Appendix G to Part 403 - Pollutants Eligible for a Removal Credit

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (or carbon monoxide) in subpart E in 40 CFR part 503 are met when sewage sludge is fired in a sewage sludge incinerator: Acrylonitrile, ldrin/Dieldrin(total), Benzene, Benzidine, Benzo(a)pyrene, Bis(2... Unlined 1 Lined 2 I Arsenic 3 100 Aldrin/Dieldrin (Total) 2.7 Benzene 3 16 140 3400 Benzo(a)pyrene 15...

  4. 40 CFR Appendix G to Part 403 - Pollutants Eligible for a Removal Credit

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (or carbon monoxide) in subpart E in 40 CFR part 503 are met when sewage sludge is fired in a sewage sludge incinerator: Acrylonitrile, ldrin/Dieldrin(total), Benzene, Benzidine, Benzo(a)pyrene, Bis(2... Unlined 1 Lined 2 I Arsenic 3 100 Aldrin/Dieldrin (Total) 2.7 Benzene 3 16 140 3400 Benzo(a)pyrene 15...

  5. A method for the production of weakly acidic cation exchange resins

    NASA Astrophysics Data System (ADS)

    Heller, H.; Werner, F.; Mitschker, A.; Diehl, H. V.; Schaefer, A.

    1991-12-01

    The invention relates to a nonpolluting method for the production of weakly acidic cation exchange resins by saponification of cross-linked acrylonitrile bead polymers, with an alkaline saponification agent at elevated temperature, according to which method the bead polymer and alkaline saponification agent are jointly added only at elevated temperature.

  6. 40 CFR 180.960 - Polymers; exemptions from the requirement of a tolerance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... specified for defining a low-risk polymer in 40 CFR 723.250, as an inert ingredient in a pesticide chemical... weight (in amu), 1,200 None Acrylonitrile-butadiene copolymer conforming to 21 CFR 180.22, minimum... 25086-29-7 Editorial Note: For Federal Register citations affecting § 180.960, see the List of...

  7. 40 CFR 180.960 - Polymers; exemptions from the requirement of a tolerance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... specified for defining a low-risk polymer in 40 CFR 723.250, as an inert ingredient in a pesticide chemical... weight (in amu), 1,200 None Acrylonitrile-butadiene copolymer conforming to 21 CFR 180.22, minimum... Federal Register citations affecting § 180.960, see the List of CFR Sections Affected, which appears...

  8. Vapor-liquid equilibria of copolymer + solvent and homopolymer + solvent binaries: New experimental data and their correlation

    SciTech Connect

    Gupta, R.B.; Prausnitz, J.M.

    1995-07-01

    Sixty-four isothermal data sets for vapor-liquid equilibria (VLE) for polymer + solvent binaries have been obtained using a gravimetric sorption technique, in the range of 23.5--80 C. Solvents studied were acetone, acetonitrile, 1-butanol, 1,2-dichloroethane, chloroform, cyclohexane, hexane, methanol, octane, pentane, and toluene. Copolymers studied were poly(acrylonitrile-co-butadiene), poly(styrene-co-acrylonitrile), poly(styrene-co-butadiene), poly(styrene-co-butyl methacrylate), poly(vinyl acetate-co-ethylene), and poly(vinyl acetate-co-vinyl chloride). All copolymers were random copolymers. Some homopolymers were also studied: polyacrylonitrile, polybutadiene, poly(butyl methacrylate), poly(ethylene oxide), polystyrene, and poly(vinyl acetate). The composition of the copolymer may have a surprising effect on VLE. Normally, deviation from ideal behavior lies between those of the constituent homopolymers, according to the copolymer composition, as observed for cyclohexane + poly(ethylene-co-vinyl acetate) and chloroform + poly(styrene-co-butyl methacrylate). However, the strong nonideal behavior observed for systems containing hydrocarbons and poly(butadiene-co-acrylonitrile) shows that the effect of acrylonitrile is in excess of that expected form the copolymer composition. The perturbed hard-sphere chain (PHSC) equation of state was used to represent VLE of the copolymer solutions studied here.

  9. 21 CFR 175.360 - Vinylidene chloride copolymer coatings for nylon film.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... is applied as a continuous film over one or both sides of a base film produced from nylon resins... produced by copolymerizing vinylidene chloride with one or more of the monomers acrylic acid, acrylonitrile, ethyl acrylate, methacrylic acid, methyl acrylate, methyl methacrylate (CAS Reg. No. 80-62-6;...

  10. Industrial Organic Electrosynthesis.

    ERIC Educational Resources Information Center

    Wagenknecht, John H.

    1983-01-01

    Four examples of industrial electrochemical synthesis of organic compounds are described. These include acrylonitrile dimerization, tetramethyl lead, electrochemical fluorination, and production of diacetone-2-keto-L-gulonic acid. Additional examples are also cited, including the production of several compounds by the BASF company of Germany. (JN)

  11. 40 CFR 180.960 - Polymers; exemptions from the requirement of a tolerance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... specified for defining a low-risk polymer in 40 CFR 723.250, as an inert ingredient in a pesticide chemical... weight (in amu), 1,200 None Acrylonitrile-butadiene copolymer conforming to 21 CFR 180.22, minimum... Federal Register citations affecting § 180.960, see the List of CFR Sections Affected, which appears...

  12. 40 CFR 180.960 - Polymers; exemptions from the requirement of a tolerance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... specified for defining a low-risk polymer in 40 CFR 723.250, as an inert ingredient in a pesticide chemical... Acrylonitrile-butadiene copolymer conforming to 21 CFR 180.22, minimum average molecular weight (in amu), 1,000... Federal Register citations affecting § 180.960, see the List of CFR Sections Affected, which appears...

  13. 40 CFR 180.960 - Polymers; exemptions from the requirement of a tolerance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... specified for defining a low-risk polymer in 40 CFR 723.250, as an inert ingredient in a pesticide chemical... weight (in amu), 1,200 None Acrylonitrile-butadiene copolymer conforming to 21 CFR 180.22, minimum... Federal Register citations affecting § 180.960, see the List of CFR Sections Affected, which appears...

  14. 40 CFR Table 6 to Subpart Jjj of... - Known Organic HAP Emitted From the Production of Thermoplastic Products

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 12 2013-07-01 2013-07-01 false Known Organic HAP Emitted From the... 63—Known Organic HAP Emitted From the Production of Thermoplastic Products Thermoplastic product/Subcategory Organic HAP/chemical name(CAS No.) Acet-aldehyde (75-07-0) Acrylo-nitrile (107-13-1) 1,3...

  15. Polymeric Additives For Graphite/Epoxy Composites

    NASA Technical Reports Server (NTRS)

    Kourtides, D. A.; Nir, Z.

    1990-01-01

    Report describes experimental studies of properties of several graphite/epoxy composites containing polymeric additives as flexibilizing or toughening agents. Emphasizes effects of brominated polymeric additives (BPA's) with or without carboxy-terminated butadiene acrylonitrile rubber. Reviews effects of individual and combined additives on fracture toughnesses, environmental stabilities, hot/wet strengths, thermomechanical behaviors, and other mechanical properties of composites.

  16. 40 CFR Table 5 to Subpart U of... - Known Organic HAP Emitted From the Production of Elastomer Products

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR.../subcategory BR EPI EPR HYP NEO NBL NBR PBR/SBRS PSR SBL SBRE Acrylonitrile (107131) X X 1,3 Butadiene (106990) X X X X X Carbon Disulfide X X X X X Carbon Tetrachloride (56235) X Chlorobenzene......

  17. 40 CFR 433.11 - Specialized definitions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Specialized definitions. The definitions set forth in 40 CFR part 401 and the chemical analysis methods set forth in 40 CFR part 136 are both incorporated here by reference. In addition, the following definitions... following toxic organics: Acenaphthene Acrolein Acrylonitrile Benzene Benzidine Carbon...

  18. 40 CFR 433.11 - Specialized definitions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... definitions. The definitions set forth in 40 CFR part 401 and the chemical analysis methods set forth in 40 CFR part 136 are both incorporated here by reference. In addition, the following definitions apply to... toxic organics: Acenaphthene Acrolein Acrylonitrile Benzene Benzidine Carbon...

  19. 40 CFR 433.11 - Specialized definitions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... definitions. The definitions set forth in 40 CFR part 401 and the chemical analysis methods set forth in 40 CFR part 136 are both incorporated here by reference. In addition, the following definitions apply to... toxic organics: Acenaphthene Acrolein Acrylonitrile Benzene Benzidine Carbon...

  20. 40 CFR 433.11 - Specialized definitions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Specialized definitions. The definitions set forth in 40 CFR part 401 and the chemical analysis methods set forth in 40 CFR part 136 are both incorporated here by reference. In addition, the following definitions... following toxic organics: Acenaphthene Acrolein Acrylonitrile Benzene Benzidine Carbon...

  1. 40 CFR 413.02 - General definitions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... to the definitions set forth in 40 CFR part 401 and the chemical analysis methods set forth in 40 CFR... part: (a) The term CN,A shall mean cyanide amenable to chlorination as defined by 40 CFR 136. (b) The... liter for the following toxic organics: Acenaphthene Acrolein Acrylonitrile Benzene Benzidine...

  2. 40 CFR 261.32 - Hazardous wastes from specific sources.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... stream from the wastewater stripper in the production of acrylonitrile (R, T) K013 Bottom stream from the... streams generated from nitrobenzene/aniline production (T) K105 Separated aqueous stream from the reactor... that is permitted under Subtitle C, or an onsite combustion unit that is permitted under the Clean...

  3. 40 CFR 261.33 - Discarded commercial chemical products, off-specification species, container residues, and spill...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-Propenenitrile U152 126-98-7 2-Propenenitrile, 2-methyl- (I,T) U008 79-10-7 2-Propenoic acid (I) U113 140-88-5 2...-10-7 2-Propenoic acid (I) U009 107-13-1 Acrylonitrile U009 107-13-1 2-Propenenitrile U010...

  4. 40 CFR 261.33 - Discarded commercial chemical products, off-specification species, container residues, and spill...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-Propenenitrile U152 126-98-7 2-Propenenitrile, 2-methyl- (I,T) U008 79-10-7 2-Propenoic acid (I) U113 140-88-5 2...-10-7 2-Propenoic acid (I) U009 107-13-1 Acrylonitrile U009 107-13-1 2-Propenenitrile U010...

  5. 40 CFR Appendix Vii to Part 261 - Basis for Listing Hazardous Waste

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., acetonitrile, hydrocyanic acid. K013 Hydrocyanic acid, acrylonitrile, acetonitrile. K014 Acetonitrile..., trichlorofluoromethane. F003 N.A. F004 Cresols and cresylic acid, nitrobenzene. F005 Toluene, methyl ethyl ketone, carbon... -tetrachlorophenols and their chlorophenoxy derivative acids, esters, ethers, amine and other salts. F021 Penta-...

  6. 40 CFR Appendix Vii to Part 261 - Basis for Listing Hazardous Waste

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., acetonitrile, hydrocyanic acid. K013 Hydrocyanic acid, acrylonitrile, acetonitrile. K014 Acetonitrile..., trichlorofluoromethane. F003 N.A. F004 Cresols and cresylic acid, nitrobenzene. F005 Toluene, methyl ethyl ketone, carbon... -tetrachlorophenols and their chlorophenoxy derivative acids, esters, ethers, amine and other salts. F021 Penta-...

  7. MW-assisted synthesis of carboxymethyl tamarind kernel polysaccharide-g-polyacrylonitrile: optimization and characterization.

    PubMed

    Meenkashi; Ahuja, Munish; Verma, Purnima

    2014-11-26

    Microwave-assisted synthesis of graft copolymer of carboxymethyl tamarind seed polysaccharide and polyacrylonitrile was carried out. The effect of formulation and process variables on grafting efficiency of carboxymethyl tamarind kernel polysaccharide-g-poly(acrylonitrile) was studied using response surface methodology. The results revealed that the significant factors affecting grafting efficiency were concentrations of ammonium persulphate, acrylonitrile and interaction effects of ammonium persulphate and acrylonitrile concentrations. The optimal calculated parameters were found to be microwave exposure time-99.48 s, microwave exposure power-160 W, concentration of acrylonitrile-0.10% (w/v), concentration of ammonium persulphate--40 mmol/l, which provided graft copolymer with grafting efficiency of 96%. The formation of graft copolymer was confirmed by FT-IR studies and validated by scanning electron micrographs. Thermogravimetric analysis indicated higher thermal stability of graft copolymer and X-ray diffraction study revealed increase in crystallinity on graft polymerization. Further, the graft copolymer showed pH dependant swelling. PMID:25256516

  8. Morita–Baylis–Hillman reaction of acrylamide with isatin derivatives

    PubMed Central

    Singh, Radhey Mohan; Tiwari, Dharmendra Kumar

    2014-01-01

    Summary The Morita–Baylis–Hillman reaction of acrylamide, as an activated alkene, has seen little development due to its low reactivity. We have developed the reaction using isatin derivatives with acrylamide, DABCO as a promoter and phenol as an additive in acetonitrile. The corresponding aza version with acrylate and acrylonitrile has also been developed resulting in high product yields. PMID:25550764

  9. 40 CFR 63.1312 - Definitions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... continuous phase with dispersed butadiene derived rubber. Acrylonitrile styrene acrylate resin (ASA) means a... monomer(s) is dispersed in droplets throughout the water phase with the aid of an emulsifying agent such... styrene. MABS is prepared by dissolving or dispersing polybutadiene rubber in a mixture of...

  10. 40 CFR 63.1312 - Definitions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... continuous phase with dispersed butadiene derived rubber. Acrylonitrile styrene acrylate resin (ASA) means a... monomer(s) is dispersed in droplets throughout the water phase with the aid of an emulsifying agent such... styrene. MABS is prepared by dissolving or dispersing polybutadiene rubber in a mixture of...

  11. 40 CFR 63.1312 - Definitions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... continuous phase with dispersed butadiene derived rubber. Acrylonitrile styrene acrylate resin (ASA) means a... monomer(s) is dispersed in droplets throughout the water phase with the aid of an emulsifying agent such... styrene. MABS is prepared by dissolving or dispersing polybutadiene rubber in a mixture of...

  12. 40 CFR 63.1312 - Definitions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... copolymer continuous phase with dispersed butadiene derived rubber. Acrylonitrile styrene acrylate resin.... Emulsion process means a process where the monomer(s) is dispersed in droplets throughout the water phase... styrene. MABS is prepared by dissolving or dispersing polybutadiene rubber in a mixture of...

  13. 40 CFR 63.11397 - What General Provisions apply to this subpart?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... apply to this subpart? (a) You must meet the requirements of the General Provisions in 40 CFR part 63... requirements of 40 CFR part 60, subpart Kb for each tank that stores acrylonitrile.” (4) This certification of... malfunction plan in accordance with the requirements of 40 CFR 63.6(e)(3).” (c) If you own or operate a...

  14. 40 CFR 63.11397 - What General Provisions apply to this subpart?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... apply to this subpart? (a) You must meet the requirements of the General Provisions in 40 CFR part 63... requirements of 40 CFR part 60, subpart Kb for each tank that stores acrylonitrile.” (4) This certification of... malfunction plan in accordance with the requirements of 40 CFR 63.6(e)(3).” (c) If you own or operate a...

  15. 40 CFR 63.11397 - What General Provisions apply to this subpart?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... apply to this subpart? (a) You must meet the requirements of the General Provisions in 40 CFR part 63... requirements of 40 CFR part 60, subpart Kb for each tank that stores acrylonitrile.” (4) This certification of... malfunction plan in accordance with the requirements of 40 CFR 63.6(e)(3).” (c) If you own or operate a...

  16. 40 CFR 63.11397 - What General Provisions apply to this subpart?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... apply to this subpart? (a) You must meet the requirements of the General Provisions in 40 CFR part 63... requirements of 40 CFR part 60, subpart Kb for each tank that stores acrylonitrile.” (4) This certification of... malfunction plan in accordance with the requirements of 40 CFR 63.6(e)(3).” (c) If you own or operate a...

  17. 40 CFR 63.11397 - What General Provisions apply to this subpart?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... apply to this subpart? (a) You must meet the requirements of the General Provisions in 40 CFR part 63... requirements of 40 CFR part 60, subpart Kb for each tank that stores acrylonitrile.” (4) This certification of... malfunction plan in accordance with the requirements of 40 CFR 63.6(e)(3).” (c) If you own or operate a...

  18. Preparation and characterization of magnetic thermoplastic-based nanocomposites

    NASA Astrophysics Data System (ADS)

    Thu, T. V.; Takamura, T.; Tsetserukou, D.; Sandhu, A.

    2014-02-01

    We developed a facile method for the preparation of magnetic nanocomposites based on the popular thermoplastic, acrylonitrile butadiene styrene (ABS). The nanocomposites were produced by liquid blending of ABS and Ni nanorods (NRs), followed by solvent evaporation. The characterizations showed that the nanocomposites were magnetic and Ni NRs were uniformly distributed in polymer matrix.

  19. Towards developing an efficient sensitive element for trinitrotoluene detection: TiO2 thin films functionalized with molecularly imprinted copolymer films

    NASA Astrophysics Data System (ADS)

    Lazau, Carmen; Iordache, Tanta-Verona; Florea, Ana-Mihaela; Orha, Corina; Bandas, Cornelia; Radu, Anita-Laura; Sarbu, Andrei; Rotariu, Traian

    2016-10-01

    In this study, TiO2 films were successfully grown in-situ onto a FTO substrate by a hydrothermal method, using TiCl4 as Ti precursor, and further on functionalized with a 2,4,6-trinitrotoluene-molecularly imprinted polymer (TNT-MIP) film as a preliminary step in developing a trinitrotoluene (TNT) reusable sensor to overcome the international security issues. For investigating the TiO2 film thickness, crystalline structure and morphology, the films were autoclaved at 200 °C at different times. The X-ray diffraction showed that TiO2 films possessed a rutile structure, with no cracks visible by atomic force microscopy (AFM), and the films morphology observed by scanning electron microscopy (SEM) was highly dependent upon the hydrothermal treatment time. Yet, the TiO2 films with a more porous surface were more suitable for TNT-MIP film deposit. Rheology of precursor polymer film solutions, based on poly (acrylonitrile-co-acrylic acid), poly (acrylonitrile-co-methacrylic acid) or poly (acrylonitrile- co-itaconic acid), and the structure and adherence of TNT-MIP films were investigated in order to establish the correct recipe of the MIP. The removal yield of TNT from the imprinted films, the thickness, the porosity and the compatibility with the inorganic TiO2 film were adequate for the poly (acrylonitrile-co-acrylic acid) system with an acrylonitrile: acrylic acid practical ratio of 86.1:13.9 (wt./wt.). Farmore, AFM morphology corroborated with SEM results highlighted the effect of TNT imprinting in the copolymer matrix as the surface of the imprinted layer was quite different from that of the non-imprinted layer.

  20. Activation of Inactive Nitrogenase by Acid-Treated Component I

    PubMed Central

    Nagatani, H. H.; Shah, Vinod K.; Brill, Winston J.

    1974-01-01

    When Azotobacter vinelandii was derepressed for nitrogenase synthesis in a N-free medium containing tungstate instead of molybdate, an inactive component I was synthesized. Although this inactive component I could be activated in vivo upon addition of molybdate to the medium, it could not be activated in vitro when molybdate was added to the extracts. Activation occurred, however, when an acid-treated component I was added to extracts of cells derepressed in medium containing tungstate. Acid treatment completely abolished component I activity. Mutant strains UW45 and UW10 were unable to fix N2. Both strains synthesized normal levels of component II but produced inactive component I. Acid-treated component I activated inactive component I in extracts of mutant strain UW45 but not mutant strain UW10. This activating factor could be obtained from N2-fixing Klebsiella pneumoniae, Clostridium pasteurianum, and Rhodospirillum rubrum. PMID:4218230

  1. First test of an enriched ^{116}CdWO_4 scintillating bolometer for neutrinoless double-beta-decay searches

    NASA Astrophysics Data System (ADS)

    Barabash, A. S.; Danevich, F. A.; Gimbal-Zofka, Y.; Giuliani, A.; Mancuso, M.; Konovalov, S. I.; de Marcillac, P.; Marnieros, S.; Nones, C.; Novati, V.; Olivieri, E.; Poda, D. V.; Shlegel, V. N.; Tretyak, V. I.; Umatov, V. I.; Zolotarova, A. S.

    2016-09-01

    For the first time, a cadmium tungstate crystal scintillator enriched in ^{116}Cd has been succesfully tested as a scintillating bolometer. The measurement was performed above ground at a temperature of 18 mK. The crystal mass was 34.5 g and the enrichment level ˜ 82 %. Despite a substantial pile-up effect due to above-ground operation, the detector demonstrated high energy resolution (2-7 keV FWHM in 0.2-2.6 MeV γ energy range and 7.5 keV FWHM at the ^{116}Cd double-beta decay transition energy of 2813 keV), a powerful particle identification capability and a high level of internal radio-purity. These results prove that cadmium tungstate is a promising detector material for a next-generation neutrinoless double-beta decay bolometric experiment, like that proposed in the CUPID project (CUORE Upgrade with Particle IDentification).

  2. The textural properties and microstructure of konjac glucomannan - tungsten gels induced by DC electric fields.

    PubMed

    Wang, Lixia; Zhuang, Yuanhong; Li, Jingliang; Pang, Jie; Liu, Xiangyang

    2016-12-01

    Konjac glucomannan - tungsten (KGM-T) gels were successfully prepared under DC electric fields, in the presence of sodium tungstate. The textural properties and microstructure of the gels were investigated by Texture Analyzer, Rheometer and SEM. Based on the response surface methodology (RSM) results, the optimum conditions for KGM-T gel springiness is 0.32% sodium tungstate concentration, 0.54% KGM concentration, 24.66V voltage and 12.37min treatment time. Under these conditions, the maximum springiness value of KGM-T gel is 1.21mm. Steady flow measurement indicated that KGM-T gel showed characteristic non-Newtonian pseudoplastic behaviour, with low flow behaviour indexes in the shear thinning region. SEM demonstrated the porosity of the freeze-dried samples. These findings may pave the way to use DC electric fields for the design and development of KGM gels and to apply KGM gels for practical applications. PMID:27374531

  3. Catalytic conversion of cellulosic biomass to ethylene glycol: Effects of inorganic impurities in biomass.

    PubMed

    Pang, Jifeng; Zheng, Mingyuan; Sun, Ruiyan; Song, Lei; Wang, Aiqin; Wang, Xiaodong; Zhang, Tao

    2015-01-01

    The effects of typical inorganic impurities on the catalytic conversion of cellulose to ethylene glycol (EG) were investigated, and the mechanism of catalyst deactivation by certain impurities were clarified. It was found that most impurities did not affect the EG yield, but some non-neutral impurities or Ca and Fe ions greatly decreased the EG yield. Conditional experiments and catalyst characterization showed that some impurities changed the pH of the reaction solution and affected the cellulose hydrolysis rate; Ca and Fe cations reacted with tungstate ions and suppressed the retro-aldol condensation. To obtain a high EG yield, the pH of the reaction solution and the concentration of tungstate ions should be respectively adjusted to 5.0-6.0 and higher than 187ppm. For raw biomass conversion, negative effects were eliminated by suitable pretreatments, and high EG yields comparable to those from pure cellulose were obtained. PMID:25459851

  4. Passively mode-locked Yb:KLu(WO4)2 oscillators.

    PubMed

    Griebner, U; Rivier, S; Petrov, V; Zorn, M; Erbert, G; Weyers, M; Mateos, X; Aguiló, M; Massons, J; Díaz, F

    2005-05-01

    We demonstrate passive mode locking based on the novel monoclinic double tungstate crystal Yb:KLu(WO4)2. We report the shortest pulses ever produced with an Yb-doped tungstate laser using a semiconductor saturable absorber. A pulse duration of 81 fs has been achieved for an average power of 70 mW at 1046 nm. We compare the performance of the polarization oriented parallel to the Nm- and Np-crystallo-optic axes. Results in the femtosecond and picosecond regime are presented applying either Ti:sapphire or diode laser pumping. The great potential of Yb:KLu(WO4)2 as an active medium for ultrashort pulses is demonstrated for the first time, to our knowledge.

  5. Precipitation Synthesis, Characterization, Morphological Control, and Photocatalyst Application of ZnWO4 Nanoparticles

    NASA Astrophysics Data System (ADS)

    Hosseinpour-Mashkani, S. Mostafa; Maddahfar, Mahnaz; Sobhani-Nasab, Ali

    2016-07-01

    Zinc tungstate nanoparticles have been successfully synthesized by a precipitation method in the presence of different polymeric surfactants. This study aimed to investigate the effect of different solvents and polymeric surfactants such as carboxymethyl cellulose, polyethylene glycol, and polyvinyl alcohol on the morphology, particle size, and crystal structure of the final product. The as-synthesized products were characterized by powder x-ray diffraction analysis, scanning electron microscopy, ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, transmission electron microscopy, and energy-dispersive x-ray spectroscopy techniques. Furthermore, the hysteresis loop of the zinc tungstate nanoparticles at room temperature revealed paramagnetic behavior. Photocatalysis results revealed that maximum methyl orange decolorization of 85% was achieved with ZnWO4 nanoparticles in 240 min under visible-light irradiation. The saturation magnetization, remanent magnetization, and coercivity of the ZnWO4 nanoparticles were 0.003 emu/g, 0.0005 emu/g, and 110 Oe, respectively.

  6. The textural properties and microstructure of konjac glucomannan - tungsten gels induced by DC electric fields.

    PubMed

    Wang, Lixia; Zhuang, Yuanhong; Li, Jingliang; Pang, Jie; Liu, Xiangyang

    2016-12-01

    Konjac glucomannan - tungsten (KGM-T) gels were successfully prepared under DC electric fields, in the presence of sodium tungstate. The textural properties and microstructure of the gels were investigated by Texture Analyzer, Rheometer and SEM. Based on the response surface methodology (RSM) results, the optimum conditions for KGM-T gel springiness is 0.32% sodium tungstate concentration, 0.54% KGM concentration, 24.66V voltage and 12.37min treatment time. Under these conditions, the maximum springiness value of KGM-T gel is 1.21mm. Steady flow measurement indicated that KGM-T gel showed characteristic non-Newtonian pseudoplastic behaviour, with low flow behaviour indexes in the shear thinning region. SEM demonstrated the porosity of the freeze-dried samples. These findings may pave the way to use DC electric fields for the design and development of KGM gels and to apply KGM gels for practical applications.

  7. A comparative evaluation of rare-earth screen-film systems. System speed, contrast, sensitometry, RMS noise, square-wave response function, and contrast-dose-detail analysis.

    PubMed

    Fearon, T; Vucich, J; Hoe, J; McSweeney, W J; Potter, B M

    1986-08-01

    We evaluated the physical characteristics and contrast-dose-detail performance of 11 rare-earth and three calcium tungstate screen-film systems. Measurements included system speed, contrast, sensitometry, RMS noise, square-wave response function, and contrast-dose-detail analysis. The major differences in physical characteristics among systems were system speed and RMS noise. Square-wave response differences were more subtle. For contrast-dose-detail analysis, the rare-earth screen-film systems and the calcium tungstate system responses were significant over a limited subject contrast range as a function of detail diameter. Relative dose efficiency in the noise-limited region is a function of the properties of the screen only and is independent of the film. PMID:3744739

  8. Advanced selective non-invasive ketone body detection sensors based on new ionophores

    NASA Astrophysics Data System (ADS)

    Sathyapalan, A.; Sarswat, P. K.; Zhu, Y.; Free, M. L.

    2014-12-01

    New molecules and methods were examined that can be used to detect trace level ketone bodies. Diseases such as type 1 diabetes, childhood hypo-glycaemia-growth hormone deficiency, toxic inhalation, and body metabolism changes are linked with ketone bodies concentration. Here we introduce, selective ketone body detection sensors based on small, environmentally friendly organic molecules with Lewis acid additives. Density functional theory (DFT) simulation of the sensor molecules (Bromo-acetonaphthone tungstate (BANT) and acetonaphthophenyl ether propiono hydroxyl tungstate (APPHT)), indicated a fully relaxed geometry without symmetry attributes and specific coordination which enhances ketone bodies sensitivity. A portable sensing unit was made in which detection media containing ketone bodies at low concentration and new molecules show color change in visible light as well as unique irradiance during UV illumination. RGB analysis, electrochemical tests, SEM characterization, FTIR, absorbance and emission spectroscopy were also performed in order to validate the ketone sensitivity of these new molecules.

  9. Differential Light Induction of Nitrate Reductases in Greening and Photobleached Soybean Seedlings 1

    PubMed Central

    Kakefuda, Genichi; Duke, Stanley H.; Duke, Stephen O.

    1983-01-01

    Soybean (Glycine max [L.] Merr.) seeds were imbibed and germinated with or without NO3−, tungstate, and norflurazon (San 9789). Norflurazon is a herbicide which causes photobleaching of chlorophyll by inhibiting carotenoid synthesis and which impairs normal chloroplast development. After 3 days in the dark, seedlings were placed in white light to induce extractable nitrate reductase activity. The induction of maximal nitrate reductase activity in greening cotyledons did not require NO3− and was not inhibited by tungstate. Induction of nitrate reductase activity in norflurazon-treated cotyledons had an absolute requirement for NO3− and was completely inhibited by tungstate. Nitrate was not detected in seeds or seedlings which had not been treated with NO3−. The optimum pH for cotyledon nitrate reductase activity from norflurazon-treated seedlings was at pH 7.5, and near that for root nitrate reductase activity, whereas the optimum pH for nitrate reductase activity from greening cotyledons was pH 6.5. Induction of root nitrate reductase activity was also inhibited by tungstate and was dependent on the presence of NO3−, further indicating that the isoform of nitrate reductase induced in norflurazon-treated cotyledons is the same or similar to that found in roots. Nitrate reductases with and without a NO3− requirement for light induction appear to be present in developing leaves. In vivo kinetics (light induction and dark decay rates) and in vitro kinetics (Arrhenius energies of activation and NADH:NADPH specificities) of nitrate reductases with and without a NO3− requirement for induction were quite different. Km values for NO3− were identical for both nitrate reductases. PMID:16663185

  10. [Activity of digestive enzymes during intraperitoneal intake of metal compounds].

    PubMed

    Zdol'nik, T D

    2001-01-01

    Digestive function was studied when three compounds from Group VIB of the Mendeleev periodic system of elements were intraperitoneally administered during 100 days. Potassium bichromate, ammonium molybdate in a dose of 0.2 mg/kg and sodium tungstate in a dose of 5.0 mg/kg (in terms of metal) were found to have a resorptive effect on pancreatic function and a local effect on the small intestinal mucosa.

  11. Effect of molybdenum and tungsten on synthesis and composition of formate dehydrogenase in Methanobacterium formicicum.

    PubMed Central

    May, H D; Patel, P S; Ferry, J G

    1988-01-01

    The influence of sodium molybdate and sodium tungstate on formate dehydrogenase activity was studied in H2-CO2-grown cultures of Methanobacterium formicicum. Depletion of molybdate from the growth medium resulted in a 75-fold decrease of intracellular molybdenum and a 35-fold decrease in enzyme activity; however, growth rate and cell yields were not influenced. By using an indirect enzyme-linked immunoassay, the amount of formate dehydrogenase approximated 3% of the total protein in cells grown in the presence of molybdate. Molybdenum-starved cells contained approximately 15-fold less formate dehydrogenase protein; Western blot (immunoblot) analysis revealed that both subunits of the enzyme were synthesized. Molybdenum starvation resulted in an increase in the amount of mRNA that hybridized to fdh-specific DNA. The results indicated an inverse relationship between the amount of transcript and the amount of formate dehydrogenase protein detected in response to molybdenum starvation. The addition of 1 mM tungstate to molybdate-containing media resulted in nearly complete loss of enzyme activity and decreased the intracellular concentration of molybdenum 10-fold. Cells grown in the presence of tungstate synthesized high amounts of inactive formate dehydrogenase and contained mRNA that hybridized to fdh-specific DNA in amounts similar to that in cells grown with sufficient molybdate. Inactive formate dehydrogenase, purified from cells grown in the presence of tungstate, had the same subunit composition and contained amounts of molybdopterin cofactor, albeit metal-free, comparable to those in the active enzyme. Images PMID:2457011

  12. Deeply Virtual Compton Scattering with CLAS

    SciTech Connect

    F.X. Girod

    2007-12-17

    The beam spin asymmetries of the reaction ep -> epg in the Bjorken regime were measured over a wide kinematical domain using the CLAS detector and a new lead-tungstate calorimeter. Through the interference of the Bethe-Heitler process with Deeply Virtual Compton Scattering, those asymmetries provide constraints for the nucleon Generalized Parton Distributions models. The observed shapes are in agreement with twist-2 dominance predictions.

  13. CMS electromagnetic calorimeter readout

    SciTech Connect

    Denes, P.; Wixted, R.

    1997-12-31

    The CMS Electromagnetic Calorimeter will consist of 109,008 crystals of Lead Tungstate (PbWO{sub 4}) arranged in a barrel (92880 crystals) and 2 endcaps (8064 crystals each). The crystals will be 25 radiation lengths long and cut in tapered shapes to make a hermetic calorimeter. The scintillation light from the crystals is captured by a photodetector, amplified and digitized. The properties of PbWO4, which is a new crystal still very much under development.

  14. Extended X-ray absorption fine structure studies of the anion complexes of FeZn uteroferrin.

    PubMed

    Wang, X; Que, L

    1998-05-26

    Molybdate and tungstate are strong inhibitors of the purple acid phosphatases. The binding modes of these anions to the FeZn derivative of uteroferrin, the purple acid phosphatase from porcine uterus (FeZnUf), have been characterized by X-ray absorption spectroscopy at both the iron and zinc K-edges. Pre-edge data show that both FeZnUf.MoO4 and FeZnUf.WO4 have six-coordinate iron sites. Analysis of the EXAFS regions shows that the iron sites of both molybdate and tungstate complexes are best simulated by a shell of three O or N atoms at 2.08-2.09 A and a shell of two O or N atoms at 1.93-1.95 A. On the other hand, the zinc sites have shells of five O or N atoms at approximately 2.1 A and one O or N atom at approximately 2.5 A. Because of the higher resolution of the FeZnUf. MoO4 data, the main shell at approximately 2.1 A can be further split into shells of four O or N at 2.04 A and one O or N at 2.22 A, the latter being associated with a molybdate oxygen. Outer-sphere EXAFS analysis indicates an Fe-Zn separation of approximately 3.4 A for both FeZnUf.MoO4 and FeZnUf.WO4, Fe-Mo/W distances of 3.2 A, and Zn-Mo/W distances of 3.6-3.7 A. Thus, molybdate and tungstate bridge the FeZn active site like phosphate, but do so unsymmetrically. The asymmetric bidentate bridging mode of molybdate and tungstate helps explain the effect of these anions on the redox properties of the diiron uteroferrin.

  15. Performance and operation of the CMS electromagnetic calorimeter

    NASA Astrophysics Data System (ADS)

    CMS Collaboration

    2010-03-01

    The operation and general performance of the CMS electromagnetic calorimeter using cosmic-ray muons are described. These muons were recorded after the closure of the CMS detector in late 2008. The calorimeter is made of lead tungstate crystals and the overall status of the 75 848 channels corresponding to the barrel and endcap detectors is reported. The stability of crucial operational parameters, such as high voltage, temperature and electronic noise, is summarised and the performance of the light monitoring system is presented.

  16. Polymerized Complex Sol-Gel Synthesis, Structural and Optical Properties of Monoclinic Eu3+ Doped KGd(WO4)2 Crystalline Red Phosphors

    NASA Astrophysics Data System (ADS)

    Thangaraju, D.; Durairajan, A.; Babu, S. Moorthy; Hayakawa, Y.

    2011-10-01

    1% Eu3+ doped KGd(WO4)2 (KGW) was synthesized through Pechini sol-gel process and crystallized by subsequent annealing at high temperature. Potassium nitrate, gadolinium nitrate and ammonium para tungstate precursors were mixed with citric acid and ethylene glycol to synthesis the polymerizable complex gel. The gel was heated to 250 °C for decomposition of polymer, which after the brownish white powder was used to synthesis the pure form of 1% Eu:KGW. The pre-fired powder was further heated at high temperature/s (550, 600, 650 and 700 °C) for calcination. The properties of heat treated samples were characterized by powder XRD, FT-IR, Raman, FESEM and fluorescence analysis to understand the crystallinity, organic liberation, tungstate ribbon formation, surface morphology and emission nature, respectively. Phase evaluation from the amorphous pre-fired sample to well crystalline KGW powder formation was confirmed with powder XRD analysis. Powders calcined at 600 °C show the appearance of monoclinic phase of KGW. Crystalline peaks without intermediate compound peaks were observed for samples calcined at 700 °C. Gel degradation and formation of double tungstate was clearly seen in the FT-IR spectrum. FT-IR spectrum of synthesized gel also, confirms the citrate formation and etherification. FESEM analysis reveals the size and morphology of the powder. Double tungstate formation from the amorphous powder was analyzed using laser Raman spectral analysis. The emission property of the europium doped KGW was analyzed using fluorescence. Changes in emission intensity was observed for samples calcined at different temperatures.

  17. Molybdate binding by ModA, the periplasmic component of the Escherichia coli mod molybdate transport system.

    PubMed

    Imperial, J; Hadi, M; Amy, N K

    1998-03-13

    ModA, the periplasmic-binding protein of the Escherichia coli mod transport system was overexpressed and purified. Binding of molybdate and tungstate to ModA was found to modify the UV absorption and fluorescence emission spectra of the protein. Titration of these changes showed that ModA binds molybdate and tungstate in a 1:1 molar ratio. ModA showed an intrinsic fluorescence emission spectrum attributable to its three tryptophanyl residues. Molybdate binding caused a conformational change in the protein characterized by: (i) a shift of tryptophanyl groups to a more hydrophobic environment; (ii) a quenching (at pH 5.0) or enhancement (at pH 7.8) of fluorescence; and (iii) a higher availability of tryptophanyl groups to the polar quencher acrylamide. The tight binding of molybdate did not allow an accurate estimation of the binding constants by these indirect methods. An isotopic binding method with 99MoO42- was used for accurate determination of KD (20 nM) and stoichiometry (1:1 molar ratio). ModA bound tungstate with approximately the same affinity, but did not bind sulfate or phosphate. These KDs are 150- to 250-fold lower than those previously reported, and compatible with the high molybdate transport affinity of the mod system. The affinity of ModA for molybdate was also determined in vivo and found to be similar to that determined in vitro.

  18. Anion binding in biological systems

    NASA Astrophysics Data System (ADS)

    Feiters, Martin C.; Meyer-Klaucke, Wolfram; Kostenko, Alexander V.; Soldatov, Alexander V.; Leblanc, Catherine; Michel, Gurvan; Potin, Philippe; Küpper, Frithjof C.; Hollenstein, Kaspar; Locher, Kaspar P.; Bevers, Loes E.; Hagedoorn, Peter-Leon; Hagen, Wilfred R.

    2009-11-01

    We compare aspects of biological X-ray absorption spectroscopy (XAS) studies of cations and anions, and report on some examples of anion binding in biological systems. Brown algae such as Laminaria digitata (oarweed) are effective accumulators of I from seawater, with tissue concentrations exceeding 50 mM, and the vanadate-containing enzyme haloperoxidase is implicated in halide accumulation. We have studied the chemical state of iodine and its biological role in Laminaria at the I K edge, and bromoperoxidase from Ascophyllum nodosum (knotted wrack) at the Br K edge. Mo is essential for many forms of life; W only for certain archaea, such as Archaeoglobus fulgidus and the hyperthermophilic archaeon Pyrococcus furiosus, and some bacteria. The metals are bound and transported as their oxo-anions, molybdate and tungstate, which are similar in size. The transport protein WtpA from P. furiosus binds tungstate more strongly than molybdate, and is related in sequence to Archaeoglobus fulgidus ModA, of which a crystal structure is known. We have measured A. fulgidus ModA with tungstate at the W L3 (2p3/2) edge, and compared the results with the refined crystal structure. XAS studies of anion binding are feasible even if only weak interactions are present, are biologically relevant, and give new insights in the spectroscopy.

  19. Aerobic Hydrogen Production via Nitrogenase in Azotobacter vinelandii CA6.

    PubMed

    Noar, Jesse; Loveless, Telisa; Navarro-Herrero, José Luis; Olson, Jonathan W; Bruno-Bárcena, José M

    2015-07-01

    The diazotroph Azotobacter vinelandii possesses three distinct nitrogenase isoenzymes, all of which produce molecular hydrogen as a by-product. In batch cultures, A. vinelandii strain CA6, a mutant of strain CA, displays multiple phenotypes distinct from its parent: tolerance to tungstate, impaired growth and molybdate transport, and increased hydrogen evolution. Determining and comparing the genomic sequences of strains CA and CA6 revealed a large deletion in CA6's genome, encompassing genes related to molybdate and iron transport and hydrogen reoxidation. A series of iron uptake analyses and chemostat culture experiments confirmed iron transport impairment and showed that the addition of fixed nitrogen (ammonia) resulted in cessation of hydrogen production. Additional chemostat experiments compared the hydrogen-producing parameters of different strains: in iron-sufficient, tungstate-free conditions, strain CA6's yields were identical to those of a strain lacking only a single hydrogenase gene. However, in the presence of tungstate, CA6 produced several times more hydrogen. A. vinelandii may hold promise for developing a novel strategy for production of hydrogen as an energy compound.

  20. Cathodoluminescence studies of commercial and nano-structured scintillators

    NASA Astrophysics Data System (ADS)

    McDoanld, Warren; McKinney, George; Tzolov, Marian

    2014-03-01

    Scintillators have applications in fundamental research and in consumer products, e.g. detectors, scanners, and televisions. This research focused on analyzing the cathodoluminescence of different single-crystal scintillators with an originally developed method for evaluation of their performance, which allows for a direct comparison of different scintillators. We have studied yttrium aluminum garnet (YAG), yttrium aluminum perovskite (YAP) scintillators, zinc oxide single crystal, zinc tungstate single crystal, zinc oxide nanowires, and zinc tungstate film. The commercial scintillators are covered with conductive film which prevents low energy electrons from effectively interacting with the scintillator. We have varied the voltage accelerating the electrons with the intention of finding the threshold below which this effect will impact the performance of the scintillators. The same procedure was followed for the nanowires and zinc tungstate film which have enough conductivity and don't require a top conducting film. The threshold was established to be around 3 kV for the YAG and there is no threshold for the films, which perform much better at these low voltages. This property of the films has the potential for application in desktop scanning electron microscopes, where the accelerating voltage is low. The voltage dependence of the cathodoluminescence intensity follows an exponential trend and we present a model explaining it.

  1. Tungsten toxicity, bioaccumulation, and compartmentalization into organisms representing two trophic levels.

    PubMed

    Kennedy, Alan J; Johnson, David R; Seiter, Jennifer M; Lindsay, James H; Boyd, Robert E; Bednar, Anthony J; Allison, Paul G

    2012-09-01

    Metallic tungsten has civil and military applications and was considered a green alternative to lead. Recent reports of contamination in drinking water and soil have raised scrutiny and suspended some applications. This investigation employed the cabbage Brassica oleracae and snail Otala lactea as models to determine the toxicological implications of sodium tungstate and an aged tungsten powder-spiked soil containing monomeric and polymeric tungstates. Aged soil bioassays indicated cabbage growth was impaired at 436 mg of W/kg, while snail survival was not impacted up to 3793 mg of W/kg. In a dermal exposure, sodium tungstate was more toxic to the snail, with a lethal median concentration of 859 mg of W/kg. While the snail significantly bioaccumulated tungsten, predominately in the hepatopancreas, cabbage leaves bioaccumulated much higher concentrations. Synchrotron-based mapping indicated the highest levels of W were in the veins of cabbage leaves. Our results suggest snails consuming contaminated cabbage accumulated higher tungsten concentrations relative to the concentrations directly bioaccumulated from soil, indicating the importance of robust trophic transfer investigations. Finally, synchrotron mapping provided evidence of tungsten in the inner layer of the snail shell, suggesting potential use of snail shells as a biomonitoring tool for metal contamination.

  2. The nitrate reductase inhibitor, tungsten, disrupts actin microfilaments in Zea mays L.

    PubMed

    Adamakis, Ioannis-Dimosthenis S; Panteris, Emmanuel; Eleftheriou, Eleftherios P

    2014-05-01

    Tungsten is a widely used inhibitor of nitrate reductase, applied to diminish the nitric oxide levels in plants. It was recently shown that tungsten also has heavy metal attributes. Since information about the toxic effects of tungsten on actin is limited, and considering that actin microfilaments are involved in the entry of tungsten inside plant cells, the effects of tungsten on them were studied in Zea mays seedlings. Treatments with sodium tungstate for 3, 6, 12 or 24 h were performed on intact seedlings and seedlings with truncated roots. Afterwards, actin microfilaments in meristematic root and leaf tissues were stained with fluorescent phalloidin, and the specimens were examined by confocal laser scanning microscopy. While the actin microfilament network was well organized in untreated seedlings, in tungstate-treated ones it was disrupted in a time-dependent manner. In protodermal root cells, the effects of tungsten were stronger as cortical microfilaments were almost completely depolymerized and the intracellular ones appeared highly bundled. Fluorescence intensity measurements confirmed the above results. In the meristematic leaf tissue of intact seedlings, no depolymerization of actin microfilaments was noticed. However, when root tips were severed prior to tungstate application, both cortical and endoplasmic actin networks of leaf cells were disrupted and bundled after 24 h of treatment. The differential response of root and leaf tissues to tungsten toxicity may be due to differential penetration and absorption, while the effects on actin microfilaments could not be attributed to the nitric oxide depletion by tungsten.

  3. Dopant and excitation wavelength dependent color-tunable white light-emitting Ln(3+):Y2WO6 materials (Ln(3+) = Sm, Eu, Tb, Dy).

    PubMed

    Van Deun, Rik; Ndagsi, Dorine; Liu, Jing; Van Driessche, Isabel; Van Hecke, Kristof; Kaczmarek, Anna M

    2015-09-01

    Microstructured Y2WO6 materials were prepared in a hydrothermal synthesis in the presence of glycerol, which was employed as both a solvent and a structure directing agent, after which they were heat treated at 1100 °C. These materials, similar to other previously reported Y2WO6 as well as other rare-earth tungstate structures, showed interesting luminescence properties. Six Ln(3+) doped or co-doped samples, which showed white light emission, are described in this paper. It was observed that the doping ion(s)/doping percentage, heat treatment of the material, as well as the chosen excitation wavelength could be used to tune the emission color of the samples to obtain white light with a warmer or colder undertone. The luminescence lifetimes, quantum yields, CIE coordinates and correlated color temperatures for these samples were determined. Additionally, for the co-doped Y2WO6 samples the energy transfer mechanisms were proposed because a significant change in the luminescence properties was observed after heat treatment. This can be linked to the conversion from distorted tungstate groups in the precursor material to regular tungstate groups in the heat treated material. PMID:26228995

  4. Aerobic Hydrogen Production via Nitrogenase in Azotobacter vinelandii CA6

    PubMed Central

    Noar, Jesse; Loveless, Telisa; Navarro-Herrero, José Luis; Olson, Jonathan W.

    2015-01-01

    The diazotroph Azotobacter vinelandii possesses three distinct nitrogenase isoenzymes, all of which produce molecular hydrogen as a by-product. In batch cultures, A. vinelandii strain CA6, a mutant of strain CA, displays multiple phenotypes distinct from its parent: tolerance to tungstate, impaired growth and molybdate transport, and increased hydrogen evolution. Determining and comparing the genomic sequences of strains CA and CA6 revealed a large deletion in CA6's genome, encompassing genes related to molybdate and iron transport and hydrogen reoxidation. A series of iron uptake analyses and chemostat culture experiments confirmed iron transport impairment and showed that the addition of fixed nitrogen (ammonia) resulted in cessation of hydrogen production. Additional chemostat experiments compared the hydrogen-producing parameters of different strains: in iron-sufficient, tungstate-free conditions, strain CA6's yields were identical to those of a strain lacking only a single hydrogenase gene. However, in the presence of tungstate, CA6 produced several times more hydrogen. A. vinelandii may hold promise for developing a novel strategy for production of hydrogen as an energy compound. PMID:25911479

  5. Trichoderma harzianum Produces a New Thermally Stable Acid Phosphatase, with Potential for Biotechnological Application

    PubMed Central

    Souza, Amanda Araújo; Leitão, Vanessa Oliveira; Ramada, Marcelo Henrique; Mehdad, Azadeh; Georg, Raphaela de Castro; Ulhôa, Cirano José; de Freitas, Sonia Maria

    2016-01-01

    Acid phosphatases (ACPases) are produced by a variety of fungi and have gained attention due their biotechnological potential in industrial, diagnosis and bioremediation processes. These enzymes play a specific role in scavenging, mobilization and acquisition of phosphate, enhancing soil fertility and plant growth. In this study, a new ACPase from Trichoderma harzianum, named ACPase II, was purified and characterized as a glycoprotein belonging to the acid phosphatase family. ACPase II presents an optimum pH and temperature of 3.8 and 65°C, respectively, and is stable at 55°C for 120 min, retaining 60% of its activity. The enzyme did not require metal divalent ions, but was inhibited by inorganic phosphate and tungstate. Affinity for several phosphate substrates was observed, including phytate, which is the major component of phosphorus in plant foods. The inhibition of ACPase II by tungstate and phosphate at different pH values is consistent with the inability of the substrate to occupy its active site due to electrostatic contacts that promote conformational changes, as indicated by fluorescence spectroscopy. A higher affinity for tungstate rather than phosphate at pH 4.0was observed, in accordance with its highest inhibitory effect. Results indicate considerable biotechnological potential of the ACPase II in soil environments. PMID:26938873

  6. Trichoderma harzianum Produces a New Thermally Stable Acid Phosphatase, with Potential for Biotechnological Application.

    PubMed

    Souza, Amanda Araújo; Leitão, Vanessa Oliveira; Ramada, Marcelo Henrique; Mehdad, Azadeh; Georg, Raphaela de Castro; Ulhôa, Cirano José; de Freitas, Sonia Maria

    2016-01-01

    Acid phosphatases (ACPases) are produced by a variety of fungi and have gained attention due their biotechnological potential in industrial, diagnosis and bioremediation processes. These enzymes play a specific role in scavenging, mobilization and acquisition of phosphate, enhancing soil fertility and plant growth. In this study, a new ACPase from Trichoderma harzianum, named ACPase II, was purified and characterized as a glycoprotein belonging to the acid phosphatase family. ACPase II presents an optimum pH and temperature of 3.8 and 65 °C, respectively, and is stable at 55 °C for 120 min, retaining 60% of its activity. The enzyme did not require metal divalent ions, but was inhibited by inorganic phosphate and tungstate. Affinity for several phosphate substrates was observed, including phytate, which is the major component of phosphorus in plant foods. The inhibition of ACPase II by tungstate and phosphate at different pH values is consistent with the inability of the substrate to occupy its active site due to electrostatic contacts that promote conformational changes, as indicated by fluorescence spectroscopy. A higher affinity for tungstate rather than phosphate at pH 4.0 was observed, in accordance with its highest inhibitory effect. Results indicate considerable biotechnological potential of the ACPase II in soil environments. PMID:26938873

  7. Novel pseudo-morphotactic synthesis and characterization of tungsten nitride nanoplates

    SciTech Connect

    Chen Deliang; Wen Hejing; Li Tao; Yin Li; Fan Bingbing; Wang Hailong; Zhang Rui; Li Xinjian; Xu Hongliang; Lu Hongxia; Yang Daoyuan; Sun Jing; Gao Lian

    2011-02-15

    A novel pseudo-morphotactic transformation route was developed to synthesize polycrystalline {beta}-W{sub 2}N nanoplates by thermally treating tungstate-based inorganic-organic hybrid nanobelts with a lamellar microstructure in an NH{sub 3} flow. The tungstate-based hybrid nanobelts were formed in a water-in-oil-microemulsion-like 'commercial H{sub 2}WO{sub 4} powders/n-octylamine/heptane' reaction system. The as-obtained hybrid nanobelts were thermally treated in an NH{sub 3} atmosphere at 650-800 {sup o}C for 2 h to form cubic {beta}-W{sub 2}N nanoplates. XRD, SEM, TEM, FT-IR and TG-DTA were used to characterize the precursors and their final products. The polycrystalline {beta}-W{sub 2}N nanoplates derived from hybrid nanobelts, with side lengths of several hundred nanometers, consist of small nanocrystals with an average grain size of 3.2 nm. The formation of {beta}-W{sub 2}N nanoplates involved two steps: decomposing tungstate-based hybrid nanobelts into WO{sub y} and W species and then nitridizing the active W-containing species to {beta}-W{sub 2}N nanocrystals in an NH{sub 3} flow. The platelike morphology of the {beta}-W{sub 2}N nanocrystals was inherited from the precursor of tungstate-based inorganic-organic hybrid nanobelts. -- A novel pseudo-morphotactic transformation route was developed to synthesize {beta}-W{sub 2}N nanoplates by thermally treating tungstate-based inorganic-organic hybrid nanobelts, the morphology of which was inherited to the {beta}-W{sub 2}N nanocrystals. Research highlights: {yields} We synthesize {beta}-W{sub 2}N nanoplates using inorganic-organic hybrid nanobelts as precursors. {yields} {beta}-W{sub 2}N nanoplates are formed at 650-800 {sup o}C for 2 h in an NH{sub 3} flow. {yields} {beta}-W{sub 2}N nanoplates consist of small nanocrystals. {yields} The plate-like morphology of {beta}-W{sub 2}N is inherited from its hybrid precursor. {yields} The pseudo-morphotactic transformation route is suitable for large-scale synthesis.

  8. The polymer-like organic material in the Orgueil meteorite

    NASA Technical Reports Server (NTRS)

    Bandurski, E. L.; Nagy, B.

    1976-01-01

    Results are reported for analysis of polymeric organic material contained in powder from the Orgueil chondrite, using a stepwise high-vacuum pyrolysis-gas chromatography-mass spectrometry technique. Pyrolysis products obtained include a series of alkanes and alkenes to C8, an extensive series of alkylbenzene isomers, thiophene, alkylthiophenes, benzothiophene, acetonitrile, acrylonitrile, benzonitrile, acetone, and phenol. Most of these products are shown to be similar both qualitatively and quantitatively to those previously obtained from solvent-extracted Allende powder, indicating a basically aromatic and heteroaromatic polymer matrix with short aliphatic bridges or side chains. The production of acrylonitrile, acetonitrile, and benzonitrile (common breakdown products of amino acids) from the insoluble organic material is taken to suggest that amino acids exist in an insoluble form, perhaps as peptides, in the meteorite's polymeric component. Similarities between the structure of the Orgueil polymeric material and terrestrial kerogen are discussed which raise the possibility that both might have been produced in part by similar reactions.

  9. Enzymatic degradation of aliphatic nitriles by Rhodococcus rhodochrous BX2, a versatile nitrile-degrading bacterium.

    PubMed

    Fang, Shumei; An, Xuejiao; Liu, Hongyuan; Cheng, Yi; Hou, Ning; Feng, Lu; Huang, Xinning; Li, Chunyan

    2015-06-01

    Nitriles are common environmental pollutants, and their removal has attracted increasing attention. Microbial degradation is considered to be the most acceptable method for removal. In this work, we investigated the biodegradation of three aliphatic nitriles (acetonitrile, acrylonitrile and crotononitrile) by Rhodococcus rhodochrous BX2 and the expression of their corresponding metabolic enzymes. This organism can utilize all three aliphatic nitriles as sole carbon and nitrogen sources, resulting in the complete degradation of these compounds. The degradation kinetics were described using a first-order model. The degradation efficiency was ranked according to t1/2 as follows: acetonitrile>trans-crotononitrile>acrylonitrile>cis-crotononitrile. Only ammonia accumulated following the three nitriles degradation, while amides and carboxylic acids were transient and disappeared by the end of the assay. mRNA expression and enzyme activity indicated that the tested aliphatic nitriles were degraded via both the inducible NHase/amidase and the constitutive nitrilase pathways, with the former most likely preferred.

  10. Novel nanosized water soluble fluorescent micelles with embedded perylene diimide fluorophores for potential biomedical applications: cell permeability, localization and cytotoxicity.

    PubMed

    Bryaskova, Rayna; Georgiev, Nikolai I; Dimov, Stefan M; Tzoneva, Rumiana; Detrembleur, Christophe; Asiri, Abdullah M; Alamry, Khalid A; Bojinov, Vladimir B

    2015-06-01

    Novel biocompatible water-soluble fluorescent micelles with embedded perylene diimides (PDI) for intracellular applications have been prepared by self assembling of amphiphilic poly(vinyl alcohol)-b-poly(acrylonitrile) (PVA-b-PAN) copolymers in the presence of synthesized fluorophores. Amphiphilic PVA-b-PAN copolymers were obtained by selective hydrolysis of well-defined poly(vinyl acetate)-b-poly(acrylonitrile) (PVAc-b-PAN) copolymer. The preparation of the novel fluorescence micelles consisting of PVA hydrophilic shell and PAN hydrophobic core with incorporated PDI fluorophores has been confirmed by DLS and TEM analysis. The cytotoxicity of the water-soluble fluorophores and their internalization into living cells depending on the micellar concentration have been tested. It was shown that they could successfully enter in living cells without destroying their morphology. The results obtained indicate that the novel water-soluble fluorescent micelles with embedded PDI fluorophores would be suitable for potential intracellular biomedical applications.

  11. Final response to BDAT related comments document. F025, K002-K008, K011, K013-15, K046, K061, K069. volume 1-k

    SciTech Connect

    Rosengrant, L.; Craig, R.

    1990-05-01

    The contents of this article include the following: wastes from production of chlorinated aliphatics (treatment standard); inorganic pigments (support standard, background document corrections, and sampling frequency); acrylonitrile (wastewater definition, acrylonitrile standard, performance data, numerical standard vs. wet air oxidation method, and data request); still bottoms from benzal chloride (nickel standard and organic standards); spent antimony catalyst (no comments were received for this waste code); ww treatment sludges from manufacturing, formulating, and loading of lead-based initiating compounds (treatment standard, stabilization technology, deactivation technology, waste minimization, and analytical data); ammonia still lime sludge (no comments were recieved for this waste code); electric arc furnace dust (wastewater treatment standard, high temperature metals recovery and residuals, treatment technologies for nonwastewaters, and availability of high temperature metals recovery); and emission control dust/sludge from secondary lead smelting (treatment standard).

  12. Polybenzoxazole-filled nitrile butadiene rubber compositions

    NASA Technical Reports Server (NTRS)

    Gajiwala, Himansu M. (Inventor); Guillot, David G. (Inventor)

    2008-01-01

    An insulation composition that comprises at least one nitrile butadiene rubber (NBR) having an acrylonitrile content that ranges from approximately 26% by weight to approximately 35% by weight and polybenzoxazole (PBO) fibers. The NBR may be a copolymer of acrylonitrile and butadiene and may be present in the insulation composition in a range of from approximately 45% by weight to approximately 56% by weight of a total weight of the insulation composition. The PBO fibers may be present in a range of from approximately 3% by weight to approximately 10% by weight of a total weight of the insulation composition. A rocket motor including the insulation composition and a method of insulating a rocket motor are also disclosed.

  13. Design of reversible, cysteine-targeted Michael acceptors guided by kinetic and computational analysis.

    PubMed

    Krishnan, Shyam; Miller, Rand M; Tian, Boxue; Mullins, R Dyche; Jacobson, Matthew P; Taunton, Jack

    2014-09-10

    Electrophilic probes that covalently modify a cysteine thiol often show enhanced pharmacological potency and selectivity. Although reversible Michael acceptors have been reported, the structural requirements for reversibility are poorly understood. Here, we report a novel class of acrylonitrile-based Michael acceptors, activated by aryl or heteroaryl electron-withdrawing groups. We demonstrate that thiol adducts of these acrylonitriles undergo β-elimination at rates that span more than 3 orders of magnitude. These rates correlate inversely with the computed proton affinity of the corresponding carbanions, enabling the intrinsic reversibility of the thiol-Michael reaction to be tuned in a predictable manner. We apply these principles to the design of new reversible covalent kinase inhibitors with improved properties. A cocrystal structure of one such inhibitor reveals specific noncovalent interactions between the 1,2,4-triazole activating group and the kinase. Our experimental and computational study enables the design of new Michael acceptors, expanding the palette of reversible, cysteine-targeted electrophiles.

  14. Toughening reinforced epoxy composites with brominated polymeric additives

    NASA Technical Reports Server (NTRS)

    Nir, Z. (Inventor); Gilwee, W. J., Jr. (Inventor)

    1985-01-01

    Cured polyfunctional epoxy resins including tris(hydroxyphenyl)methane triglycidyl ether are toughened by addition of polybrominated polymeric additives having an EE below 1500 to the pre-cure composition. Carboxy-terminated butadiene-acrylonitrile rubber is optionally present in the pre-cure mixture as such or as a pre-formed copolymer with other reactants. Reinforced composites, particularly carbon-reinforced composites, of these resins are disclosed and shown to have improved toughness.

  15. Toughening reinforced epoxy composites with brominated polymeric additives

    NASA Technical Reports Server (NTRS)

    Nir, Z.; Gilwee, W. J., Jr. (Inventor)

    1985-01-01

    Cured polyfunctional epoxy resins including tris (hydroxyphenyl) methane triglycidyl ether are toughened by addition of polybrominated polymeric additives having an EE below 1500 to the pre-cure composition. Carboxy terminated butadiene acrylonitrile rubber is optionally present in the precure mixture as such or as a pre-formed copolymer with other reactants. Reinforced composites, particularly carbon reinforced composites, of these resins are disclosed and shown to have improved toughness.

  16. Study on some new water-soluble copolymers and polymer blends used for exploitation of oil field

    SciTech Connect

    Xu, X.; He, Q.; Zhuo, Q.; Mao, W.

    1982-01-01

    Some water-soluble polymers used for oil recovery were prepared by copolymerizing acrylamide and acrylonitrile using ammonium persulfate as initiator. The properties of the mixed aqueous solution of carboxymethly cellulose and partially hydrolyzed polyacrylamide were modified by ultrasonic technique. In addition, the gel characteristics of several etherified polyvinyl alcohols and their blends were studied and some new applications of polyvinyl were exploited. 6 refs.

  17. Toxicity of Pyrolysis Gases from Elastomers

    NASA Technical Reports Server (NTRS)

    Hilado, Carlos J.; Kosola, Kay L.; Solis, Alida N.; Kourtides, Demetrius A.; Parker, John A.

    1977-01-01

    The toxicity of the pyrolysis gases from six elastomers was investigated. The elastomers were polyisoprene (natural rubber), styrene-butadiene rubber (SBR), ethylene propylene diene terpolymer (EPDM), acrylonitrile rubber, chlorosulfonated polyethylene rubber, and polychloroprene. The rising temperature and fixed temperature programs produced exactly the same rank order of materials based on time to death. Acryltonitrile rubber exhibited the greatest toxicity under these test conditions; carbon monoxide was not found in sufficient concentrations to be the primary cause of death.

  18. Vapor-liquid equilibria for copolymer+solvent systems: Effect of intramolecular repulsion

    SciTech Connect

    Gupta, R.B.; Prausnitz, J.M.

    1995-03-01

    Role of intramolecular interactions in blend miscibility is well documented for polymer+copolymer mixtures. Some copolymer+polymer mixtures are miscible although their corresponding homopolymers are not miscible; for example, over a range of acrylonitrile content, styrene/acrylonitrile copolymers are miscible with poly(methyl methacrylate) but neither polystyrene nor polyacrylonitrile is miscible with poly(methyl methacrylate). Similarly, over a composition range, butadiene/acrylonitrile copolymers are miscible with poly(vinyl chloride) while none of the binary combinations of the homopolymers [polybutadiene, polyacrylonitrile, and poly(vinyl chloride)] are miscible. This behavior has been attributed to ``intramolecular repulsion`` between unlike copolymer segments. We have observed similar behavior in vapor-liquid equilibria (VLE) of copolymer+solvent systems. We find that acrylonitrile/butadiene copolymers have higher affinity for acetonitrile solvent than do polyacrylonitrile or polybutadiene. We attribute this non-intuitive behavior to ``intramolecular repulsion`` between unlike segments of the copolymer. This repulsive interaction is weakened when acetonitrile molecules are in the vicinity of unlike copolymer segments, favoring copolymer+solvent miscibility. We find similar behavior when acetonitrile is replaced by methyl ethyl ketone. To best knowledge, this effect has not been reported previously for VLE. We have obtained VLE data for mixtures containing a solvent and a copolymer as a function of copolymer composition. It appears that, at a given solvent partial pressure, there may be copolymer composition that yields maximum absorption of the solvent. This highly non-ideal VLE phase behavior may be useful for optimum design of a membrane for a separation process.

  19. 40 CFR Table 37 to Subpart G of... - Default Biorates for List 1 Compounds

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 10 2014-07-01 2014-07-01 false Default Biorates for List 1 Compounds.... 63, Subpt. G, Table 37 Table 37 to Subpart G of Part 63—Default Biorates for List 1 Compounds Compound name Biorate, K1L/g MLVSS-hr Acetonitrile 0.100 Acetophenone 0.538 Acrylonitrile 0.750 Biphenyl...

  20. 40 CFR Table 37 to Subpart G of... - Default Biorates for List 1 Compounds

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 10 2012-07-01 2012-07-01 false Default Biorates for List 1 Compounds.... 63, Subpt. G, Table 37 Table 37 to Subpart G of Part 63—Default Biorates for List 1 Compounds Compound name Biorate, K1L/g MLVSS-hr Acetonitrile 0.100 Acetophenone 0.538 Acrylonitrile 0.750 Biphenyl...

  1. 40 CFR Table 37 to Subpart G of... - Default Biorates for List 1 Compounds

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 10 2013-07-01 2013-07-01 false Default Biorates for List 1 Compounds.... 63, Subpt. G, Table 37 Table 37 to Subpart G of Part 63—Default Biorates for List 1 Compounds Compound name Biorate, K1L/g MLVSS-hr Acetonitrile 0.100 Acetophenone 0.538 Acrylonitrile 0.750 Biphenyl...

  2. Fluoro-Julia Olefination as a Mild, High-Yielding Route to α-Fluoro Acrylonitriles†

    PubMed Central

    del Solar, Maria; Ghosh, Arun K.; Zajc, Barbara

    2009-01-01

    Synthesis of a novel, stable reagent (1,3-benzothiazol-2-ylsulfonyl)fluoroacetonitrile from readily available ethyl α-(1,3-benzothiazol-2-ylsulfanyl)- α-fluoroacetate is reported. Aldehydes undergo condensations with (1,3-benzothiazol-2-ylsulfonyl)fluoroacetonitrile in the presence of DBU leading to α-fluoro acrylonitriles in high yields and with good Z-stereoselectivity. Lowering of reaction temperature increases the Z selectivity. PMID:18841918

  3. Investigation of the oxidative ammonolysis of propylene on oxide catalysts containing molybdenum and using the response method

    SciTech Connect

    Gadzhiev, K.N.; Adzhamov, K.Y.; Alkhazov, T.G.; Khanmamedova, A.K.

    1985-07-01

    The response method has been used to study the oxidative ammonolysis of propylene on MoO/sub 3/ and molybdenum oxide systems containing bismuth, silicon, and phosphorous ions. The response curves obtained for ammonia, propylene, CO/sub 2/, acrolein, acrylonitrile in these systems are discussed and compared with individual molybdenum trioxide. It has been shown that the modifying action of ammonia on the catalyst surfaces determines the direction of the oxidative conversion of the propylene.

  4. Surface intermediates in selective olefin oxidation and ammoxidation

    SciTech Connect

    Burrington, J.D.; Kartisek, C.T.; Grasselli, R.K.

    1983-02-01

    An investigation of the mechanism of the oxidation and ammoxidation of propylene was made. The products of the above reactions were acrylonitrile and acrolein for ammoxidation and oxidation, respectively. Also, the ammoxidation and oxidation of allyl alcohol, allyl amine, and their allylic deuterium substituted analogues was studied. It was concluded that oxidation and ammoxidation of propylene have the same rate determining step. Other conclusions about the reaction intermediates were also made.

  5. The relative fire resistance of select thermoplastic materials. [for aircraft interiors

    NASA Technical Reports Server (NTRS)

    Kourtides, D. A.; Parker, J. A.

    1978-01-01

    The relative thermal stability, flammability, and related thermochemical properties of some thermoplastic materials currently used in aircraft interiors as well as of some candidate thermoplastics were investigated. Currently used materials that were evaluated include acrylonitrile butadiene styrene, bisphenol A polycarbonate, polyphenylene oxide, and polyvinyl fluoride. Candidate thermoplastic materials evaluated include: 9,9-bis(4-hydroxyphenyl)fluorene polycarbonate-poly(dimethylsiloxane) block polymer, chlorinated polyvinylchloride homopolymer, phenolphthalein polycarbonate, polyethersulfone, polyphenylene sulfide, polyarylsulfone, and polyvinylidene fluoride.

  6. Enhancement of the grafting performance and of the water absorption of cassava starch graft copolymer by gamma radiation

    NASA Astrophysics Data System (ADS)

    Kiatkamjornwong, Suda; Meechai, Nispa

    1997-06-01

    Enhancement of the gamma radiation grafting of acrylonitrile onto gelatinized cassava starch was investigated. Infrared spectrometry was used to follow the chemical changes in the grafting reaction and from saponification. The saponified starch- g-PAN (HSPAN) was then characterized in terms of grafting parameters to provide a guide for the optimum total dose (kGy) and the appropriate ratio of starch/acrylonitrile for a fixed dose rate of 2.5 × 10 -1 kGy/min. Other dose rates were also carried out to obtain the appropriate result of grafting copolymerization and of water absorption. A thin aluminium foil, covering the inner wall of the reaction vessel, was found to be far more effective than any other metal films in the enhancement of the grafting reaction and the water absorption as well. Nitric acid in the medium increases the grafting yield and the water absorption. Methyl ether hydroquinone inhibitor was evaluated for its ability to increase homopolymerization and decrease graft reaction. When styrene was used as a comonomer, it hampered the grafting of acrylonitrile onto starch backbone. The water absorption capacity was improved by freeze-drying the HSPAN. The treatment of the HSPAN with aluminium trichloride hexahydrate was found to enhance the degree of wicking, but to decrease the water absorbency.

  7. A study of the influence of micro and nano phase morphology on the mechanical properties of a rubber-modified epoxy resin

    NASA Astrophysics Data System (ADS)

    Russell, Bobby Glenn

    Epoxy resins are thermosets with extraordinary adhesion; high strength; good resistance to creep, heat, and chemicals; and they have low shrinkage. Conversely, these polymers are brittle, they are sensitive to moisture, and they exhibit poor toughness. To improve their toughness, they are often modified by introducing dispersed rubber particles in the primary phase. In this study, the epoxy resin was modified with carboxyl-terminated butadiene acrylonitrile (CTBN), liquid-reactive rubbers. The initiator concentration, percent acrylonitrile in the CTBN rubber, and cure temperatures were altered to give varying materials properties. Statistical analysis of the morphology data showed that the percentage of rubber acrylonitrile had an effect on both the rubber particle size and volume fraction. The cure temperature had an effect on the rubber particle volume and modulus. Plots of the rubber particle size, volume fraction, and modulus versus bulk elastic storage modulus and fracture toughness revealed that rubber particle size had no effect on bulk properties, volume fraction and rubber particle modulus had an effect on both the bulk storage elastic modulus and fracture toughness.

  8. Detection of pseudouridine and other modifications in tRNA by cyanoethylation and MALDI mass spectrometry

    PubMed Central

    Mengel-Jørgensen, Jonas; Kirpekar, Finn

    2002-01-01

    Mass spectrometry plays a central role in the characterisation of modified nucleotides, but pseudouridine is a mass-silent post-transcriptional modification and hence not detectable by direct mass spectrometric analysis. We show by the use of matrix-assisted laser desorption/ionisation (MALDI) mass spectrometry that pseudouridines in tRNA can be specifically cyanoethylated by acrylonitrile without affecting the uridines. The tRNA was cyanoethylated and then subjected to digestion with either RNase A or RNase T1. Cyanoethylated digestion fragments were identified by mass spectrometric comparison of untreated and acrylonitrile-treated samples, where the addition of one acrylonitrile resulted in a mass increment of 53.0 Da. The exact modified nucleotide could be identified by tandem mass spectrometry on the cyanoethylated digestion fragment. The methodology was used to identify additional one 4-thiouridine and one pseudouridine in tRNATyrII from Escherichia coli. Furthermore, we observed that RNase A is highly tolerant towards nucleotide modifications, only being inhibited by 2′-O-methylation, whereas RNase T1 cleavage is affected by most nucleotide modifications. PMID:12466567

  9. Growth inhibition by tungsten in the sulfur-oxidizing bacterium Acidithiobacillus thiooxidans.

    PubMed

    Negishi, Atsunori; Muraoka, Tadashi; Maeda, Terunobu; Takeuchi, Fumiaki; Kanao, Tadayoshi; Kamimura, Kazuo; Sugio, Tsuyoshi

    2005-11-01

    Growth of five strains of sulfur-oxidizing bacteria Acidithiobacillus thiooxidans, including strain NB1-3, was inhibited completely by 50 microM of sodium tungstate (Na(2)WO(4)). When the cells of NB1-3 were incubated in 0.1 M beta-alanine-SO(4)(2-) buffer (pH 3.0) with 100 microM Na(2)WO(4) for 1 h, the amount of tungsten bound to the cells was 33 microg/mg protein. Approximately 10 times more tungsten was bound to the cells at pH 3.0 than at pH 7.0. The tungsten binding to NB1-3 cells was inhibited by oxyanions such as sodium molybdenum and ammonium vanadate. The activities of enzymes involved in elemental sulfur oxidation of NB1-3 cells such as sulfur oxidase, sulfur dioxygenase, and sulfite oxidase were strongly inhibited by Na(2)WO(4). These results indicate that tungsten binds to NB1-3 cells and inhibits the sulfur oxidation enzyme system of the cells, and as a result, inhibits cell growth. When portland cement bars supplemented with 0.075% metal nickel and with 0.075% metal nickel and 0.075% calcium tungstate were exposed to the atmosphere of a sewage treatment plant containing 28 ppm of H(2)S for 2 years, the weight loss of the portland cement bar with metal nickel and calcium tungstate was much lower than the cement bar containing 0.075% metal nickel.

  10. The Catalytic Scaffold fo the Haloalkanoic Acid Dehalogenase Enzyme Superfamily Acts as a Mold for the Trigonal Bipyramidal Transition State

    SciTech Connect

    Lu,Z.; Dunaway-Mariano, D.; Allen, K.

    2008-01-01

    The evolution of new catalytic activities and specificities within an enzyme superfamily requires the exploration of sequence space for adaptation to a new substrate with retention of those elements required to stabilize key intermediates/transition states. Here, we propose that core residues in the large enzyme family, the haloalkanoic acid dehalogenase enzyme superfamily (HADSF) form a 'mold' in which the trigonal bipyramidal transition states formed during phosphoryl transfer are stabilized by electrostatic forces. The vanadate complex of the hexose phosphate phosphatase BT4131 from Bacteroides thetaiotaomicron VPI-5482 (HPP) determined at 1.00 Angstroms resolution via X-ray crystallography assumes a trigonal bipyramidal coordination geometry with the nucleophilic Asp-8 and one oxygen ligand at the apical position. Remarkably, the tungstate in the complex determined to 1.03 Angstroms resolution assumes the same coordination geometry. The contribution of the general acid/base residue Asp-10 in the stabilization of the trigonal bipyramidal species via hydrogen-bond formation with the apical oxygen atom is evidenced by the 1.52 Angstroms structure of the D10A mutant bound to vanadate. This structure shows a collapse of the trigonal bipyramidal geometry with displacement of the water molecule formerly occupying the apical position. Furthermore, the 1.07 Angstroms resolution structure of the D10A mutant complexed with tungstate shows the tungstate to be in a typical 'phosphate-like' tetrahedral configuration. The analysis of 12 liganded HADSF structures deposited in the protein data bank (PDB) identified stringently conserved elements that stabilize the trigonal bipyramidal transition states by engaging in favorable electrostatic interactions with the axial and equatorial atoms of the transferring phosphoryl group.

  11. Nitrate reductase-mediated NO production enhances Cd accumulation in Panax notoginseng roots by affecting root cell wall properties.

    PubMed

    Kan, Qi; Wu, Wenwei; Yu, Wenqian; Zhang, Jiarong; Xu, Jin; Rengel, Zed; Chen, Limei; Cui, Xiuming; Chen, Qi

    2016-04-01

    Panax notoginseng (Burk) F. H. Chen is a traditional medicinal herb in China. However, the high capacity of its roots to accumulate cadmium (Cd) poses a potential risk to human health. Although there is some evidence for the involvement of nitric oxide (NO) in mediating Cd toxicity, the origin of Cd-induced NO and its function in plant responses to Cd remain unknown. In this study, we examined NO synthesis and its role in Cd accumulation in P. notoginseng roots. Cd-induced NO production was significantly decreased by application of the nitrate reductase inhibitor tungstate but not the nitric oxide synthase inhibitor L-NAME (N(G)-methyl-l-arginine acetate), indicating that nitrate reductase is the major contributor to Cd-induced NO production in P. notoginseng roots. Under conditions of Cd stress, sodium nitroprusside (SNP, an NO donor) increased Cd accumulation in root cell walls but decreased Cd translocation to the shoot. In contrast, the NO scavenger cPTIO (2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) and tungstate both significantly decreased NO-increased Cd retention in root cell walls. The amounts of hemicellulose 1 and pectin, together with pectin methylesterase activity, were increased with the addition of SNP but were decreased by cPTIO and tungstate. Furthermore, increases or decreases in hemicellulose 1 and pectin contents as well as pectin methylesterase activity fit well with the increased or decreased retention of Cd in the cell walls of P. notoginseng roots. The results suggest that nitrate reductase-mediated NO production enhances Cd retention in P. notoginseng roots by modulating the properties of the cell wall.

  12. Properties of the periplasmic ModA molybdate-binding protein of Escherichia coli.

    PubMed

    Rech, S; Wolin, C; Gunsalus, R P

    1996-02-01

    The modABCD operon, located at 17 min on the Escherichia coli chromosome, encodes the protein components of a high affinity molybdate uptake system. Sequence analysis of the modA gene (GenBank L34009) predicts that it encodes a periplasmic binding protein based on the presence of a leader-like sequence at its N terminus. To examine the properties of the ModA protein, the modA structural gene was overexpressed, and its product was purified. The ModA protein was localized to the periplasmic space of the cell, and it was released following a gentle osmotic shock. The N-terminal sequence of ModA confirmed that a leader region of 24 amino acids was removed upon export from the cell. The apparent size of ModA is 31.6 kDa as determined by gel sieve chromatography, whereas it is 22.5 kDa when examined by SDS-polyacrylamide gel electrophoresis. A ligand-dependent protein mobility shift assay was devised using a native polyacrylamide gel electrophoresis protocol to examine binding of molybdate and other anions to the ModA periplasmic protein. Whereas molybdate and tungstate were bound with high affinity (approximately 5 microM), sulfate, chromate, selenate, phosphate, and chlorate did not bind even when tested at 2 mM. A UV spectral assay revealed apparent Kd values of binding for molybdate and tungstate of 3 and 7 microM, respectively. Strains defective in the modA gene were unable to transport molybdate unless high levels of the anion were supplied in the medium. Therefore the modA gene product is essential for high affinity molybdate uptake by the cell. Tungstate interference of molybdate acquisition by the cell is apparently due in part to the high affinity of the ModA protein for this anion.

  13. Crystal structures of spinel-type Na2MoO4 and Na2WO4 revisited using neutron powder diffraction.

    PubMed

    Fortes, A Dominic

    2015-06-01

    Time-of-flight neutron powder diffraction data have been collected from Na2MoO4 and Na2WO4 to a resolution of sin (θ)/λ = 1.25 Å(-1), which is substanti-ally better than the previous analyses using Mo Kα X-rays, providing roughly triple the number of measured reflections with respect to the previous studies [Okada et al. (1974 ▶). Acta Cryst. B30, 1872-1873; Bramnik & Ehrenberg (2004 ▶). Z. Anorg. Allg. Chem. 630, 1336-1341]. The unit-cell parameters are in excellent agreement with literature data [Swanson et al. (1962 ▶). NBS Monograph No. 25, sect. 1, pp. 46-47] and the structural parameters for the molybdate agree very well with those of Bramnik & Ehrenberg (2004 ▶). However, the tungstate structure refinement of Okada et al. (1974 ▶) stands apart as being conspicuously inaccurate, giving significantly longer W-O distances, 1.819 (8) Å, and shorter Na-O distances, 2.378 (8) Å, than are reported here or in other simple tungstates. As such, this work represents an order-of-magnitude improvement in precision for sodium molybdate and an equally substantial improvement in both accuracy and precision for sodium tungstate. Both compounds adopt the spinel structure type. The Na(+) ions have site symmetry .-3m and are in octa-hedral coordination while the transition metal atoms have site symmetry -43m and are in tetra-hedral coordination.

  14. A passion for physics: Essays in honor of Geoffrey Chew

    SciTech Connect

    DeTar, C.; Finkelstein, J.; Tan, C.I.

    1985-01-01

    This book contains papers presented at a conference at tunable solid state lasers. Topics covered include: recent advances in transitional-metal-doped lasers; laser action in Cr-doped garnets and tungstates; alexandrite laser systems; an overview of NASA requirements for tunable solid state laser systems; laser pumped single pass gain; cuprous iron doped crystals for tunable laser systems; growth of fluoride laser host crystals; energy transfer in vibronic laser materials; theoretical methods for study of transition metals in crystals; and electron-phonon interaction and defect processes in laser materials.

  15. Ab-initio structure determination of β-La 2WO 6

    NASA Astrophysics Data System (ADS)

    Chambrier, M.-H.; Kodjikian, S.; Ibberson, R. M.; Goutenoire, F.

    2009-02-01

    The structure of the low-temperature form of β-La 2WO 6 has been determined from laboratory X-ray, neutron time-of-flight and electron diffraction data. This tungstate crystallizes in the non-centrosymmetric orthorhombic space group (no. 19) P2 12 12 1, with Z=8, a=7.5196(1) Å, b=10.3476(1) Å, c=12.7944(2) Å, and a measured density 7.37(1) g cm -3. The structure consists of tungsten [WO 6] octahedra and tetrahedral [OLa 4]. Tungsten polyhedra are connected such that [W 2O 11] 10- units are formed.

  16. Efficient 2-μm laser oscillation of 5% Tm{sup 3+} : KLu(WO{sub 4}){sub 2} disks and 5% Tm{sup 3+} : KLu(WO{sub 4}){sub 2}/KLu(WO{sub 4}){sub 2} composite structures

    SciTech Connect

    Vatnik, S M; Vedin, I A; Kurbatov, P F; Pavlyuk, A A

    2014-11-30

    The spectral and lasing characteristics of active disk elements made of double potassium – lutetium tungstates 5% Tm : KLuW and 5% Tm : KLuW/KLuW composite structures are comparatively studied. Laser power of about 5 W in the cw regime at a wavelength of 1.85 μm was achieved in a composite sample with the active layer thickness of 250 μm. Under quasi-cw pumping, the slope efficiency of all the studied samples exceeded 50%. It is experimentally shown that the internal stresses in the composite structures strongly affect the spectral characteristics of the laser radiation. (lasers)

  17. Role of solid acid catalysts in bio diesel production.

    PubMed

    Shivayogimath, C B; Sunita, G; Manoj Kumar, B

    2009-07-01

    Biodiesel is gaining importance as an alternate source of attractive fuel because of depleting fossil fuel resources. It is produced by trans-esterification, in which oil or fat reacts with a monohydric alcohol in presence of a catalyst. In the present work, trans-esterification of sunflower oil with methanol is carried out by using zirconia supported isopoly and heteropoly tungstates (HPAs) as catalysts. Effects of reaction parameters, such as catalyst types and its concentration, molar ratio of sunflower oil to methanol, reaction temperature and time, have been optimized to get higher conversion of sunflower oil and the product distribution of fatty acid methyl esters (FAME) in the trans-esterfication reaction.

  18. Nanocomposite scintillator, detector, and method

    DOEpatents

    Cooke, D. Wayne; McKigney, Edward A.; Muenchausen, Ross E.; Bennett, Bryan L.

    2009-04-28

    A compact includes a mixture of a solid binder and at least one nanopowder phosphor chosen from yttrium oxide, yttrium tantalate, barium fluoride, cesium fluoride, bismuth germanate, zinc gallate, calcium magnesium pyrosilicate, calcium molybdate, calcium chlorovanadate, barium titanium pyrophosphate, a metal tungstate, a cerium doped nanophosphor, a bismuth doped nanophosphor, a lead doped nanophosphor, a thallium doped sodium iodide, a doped cesium iodide, a rare earth doped pyrosilicate, or a lanthanide halide. The compact can be used in a radiation detector for detecting ionizing radiation.

  19. The CMS Electromagnetic Calorimeter

    NASA Astrophysics Data System (ADS)

    Ryan, M.

    2008-06-01

    The CMS experiment at the CERN Large Hadron Collider has placed great emphasis on precise calorimetry. The electromagnetic calorimeter (ECAL) contains 75000 scintillating lead tungstate crystals that are read out using sophisticated electronics; this paper describes these technologies and how they were implemented in the calorimeter. The results of pre-calibration measurements for the detector modules are detailed. Installation of the ECAL into the underground cavern has commenced and the commissioning process and its status are discussed. The experiment is scheduled to start in 2008 and prospects for the first year of operation and running are given.

  20. Automatic photometric titrations of calcium and magnesium in carbonate rocks

    USGS Publications Warehouse

    Shapiro, L.; Brannock, W.W.

    1955-01-01

    Rapid nonsubjective methods have been developed for the determination of calcium and magnesium in carbonate rocks. From a single solution of the sample, calcium is titrated directly, and magnesium is titrated after a rapid removal of R2O3 and precipitation of calcium as the tungstate. A concentrated and a dilute solution of disodium ethylenediamine tetraacetate are used as titrants. The concentrated solution is added almost to the end point, then the weak solution is added in an automatic titrator to determine the end point precisely.