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Sample records for barium phosphates

  1. Barium hydrogen phosphate/gelatin composites versus gelatin-free barium hydrogen phosphate: synthesis and characterization of properties.

    PubMed

    Gashti, Mazeyar Parvinzadeh; Burgener, Matthias; Stir, Manuela; Hulliger, Jürg

    2014-10-01

    Recently, attention has been spent on crystal growth of phosphate compounds in gels for studying the mechanism of in vitro crystallization processes. Here, we present a gel-based approach for the synthesis of barium hydrogen phosphate (BHP) crystals using single and double diffusion techniques in gelatin. The composite crystals were compared with analytical grade BHP powder, single and polycrystalline BHP materials using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), scanning pyroelectric microscopy (SPEM), optical microscopy (OM), thermal gravimetric analysis (TGA) and X-ray diffraction (XRD). FTIR spectra showed surface adsorption of gelatin molecules by using BHP stacked sheets due to CH2 stretching, CH2 bending and amide I vibrations are found in a gelatin content of about 2% determined by dissolution. SEM shows various crystal morphologies of the BHP/gelatin composites forming bundled micro-flakes to irregular bundled needles and spheres different from gel-free crystals. The variety in morphology depends on the ion concentration, pH of gel as well as the method of crystal growth. SPEM investigation of BHP/gelatin aggregates revealed polar domains showing alteration of the polarization. Moreover, BHP/gelatin composite crystals showed a higher thermal stability in comparison with analytical grade BHP or/and BHP single crystals due to strong interactions between gelatin and BHP. The XRD diffraction analysis demonstrated that the single and double diffusion techniques in gelatin led to the formation of orthorhombic BHP. This study demonstrates that gelatin is a useful high molecular weight biomacromolecule for controlling the crystallization of a composite material by producing a variety of morphological forms.

  2. Effect of CaF{sub 2} addition on optical properties of barium phosphate glasses

    SciTech Connect

    Kumar, N. Manoj Rao, G. Venkateswara Akhila, B. E. Shashikala, H. D.

    2014-04-24

    Ternary barium phosphate glasses, (50−X)BaO−XCaF{sub 2}−50P{sub 2}O{sub 5} have been prepared by adding 0-10 mol% of CaF{sub 2} to binary barium phosphate glasses. The amorphous nature of the prepared glasses was confirmed by X-ray diffraction technique. The UV-Visible absorption spectra have been recorded, optical band gap energy Eopt and Urbach energy Etail were determined. Shift in Eopt and Etail with increase in concentration of CaF{sub 2} is noted. FTIR analysis was carried out to investigate the short and intermediate-range orders in glasses. Shift of (P-O-P) band to higher wave number with the substitution of BaO with CaF{sub 2} shows the shortening of the phosphate chains. Hardness and density of glass samples were measured and correlated with the composition of glasses.

  3. Prospective, randomized comparison of castor oil and sodium phosphate preparation for barium enema.

    PubMed

    Apisarnthanarak, Piyaporn; Rotjanaaree, Benjaporn; Komoltri, Chulalak; Charoensak, Aphinya; Apisarnthanarak, Anucha; Hargrove, Narumol Srisuthapan

    2009-02-01

    To compare castor oil and sodium phosphate preparation (Swiff) in patients' satisfaction, efficacy for colon cleanness, side effects, and prices. One hundred patients referred for barium enema were randomized to receive castor oil (n = 50) and sodium phosphate preparation (n = 50). They graded their satisfaction using a 5-point scale (easy, acceptable, slightly difficult, extremely difficult, and unacceptable). The efficacy for colon cleanness was graded by two radiologists using a 5-point scale (excellent, easy for evaluation, acceptable, difficult for evaluation, and unacceptable). Side effects were evaluated by patients' vital signs, total number of bowel frequency, and 10 associated symptoms. Both preparations revealed no difference in patients' satisfaction (p = 0.882) and efficacy of colon cleanness (p = 0.130). Sodium phosphate preparation was more expensive (79 vs. 10 Baht) and caused higher number of bowel frequency (p < 0.001). With a cheaper price, castor oil was comparable with sodium phosphate preparation in patients' satisfaction and efficacy of colon cleanness.

  4. The chemistry of the phosphates of barium and tetravalent cations in the 1:1 stoichiometry

    SciTech Connect

    Popa, Karin Bregiroux, Damien; Konings, Rudy J.M.; Gouder, Thomas; Popa, Aurelian F.; Geisler, Thorsten; Raison, Philippe E.

    2007-08-15

    The chemistry of phosphates of barium and tetravalent cations [BaM{sup IV}(PO{sub 4}){sub 2}] is reviewed. Such phosphates crystallise in the C2/m space group for M{sup IV}=Ti, Zr, Hf, Ge, Sn, and Mo, and in the P2{sub 1}/n space group for BaTh(PO{sub 4}){sub 2}. The existence of BaM{sup IV}(PO{sub 4}){sub 2} in which M{sup IV}=Pb, Ce, and U is further evaluated. Several aspects, such as phase transitions in the compounds with yavapaiite structure, solid solutions of BaM{sup IV}(PO{sub 4}){sub 2} compounds and practical applications are briefly discussed. - Graphical abstract: Graphical representation of the variation of the unit-cell volume of BaM{sup IV}(PO{sub 4}){sub 2} as a function of the ionic radii of M{sup IV} cations. Such phosphates crystallise in the C2/m space group for M{sup IV}=Ti, Zr, Hf, Ge, Sn, and Mo, and in the P2{sub 1}/n space group for BaTh(PO{sub 4}){sub 2}. The 'BaCe(PO{sub 4}){sub 2}' phosphate previously reported does not exist, as demonstrated in the present paper. Taking into account the present evidence, it can be concluded at this stage that the existence of other Ce(IV) phosphates obtained at high temperature and reported into the literature becomes doubtful. Display Omitted.

  5. Studies on various properties of pure and Li-doped Barium Hydrogen Phosphate (BHP) single crystals

    NASA Astrophysics Data System (ADS)

    Nallamuthu, D.; Selvarajan, P.; Freeda, T. H.

    2010-12-01

    Single crystals of pure and Li-doped barium hydrogen phosphate (BHP) were grown by solution method with gel technique. Various properties of the harvested crystals were studied by carrying out single crystal and powder XRD, FTIR, TG/DTA, microhardness and dielectric studies. Atomic absorption study was carried out for Li-doped BHP crystal to check the presence of Li dopants. Unit cell dimensions and diffracting planes of the grown crystals have been identified from XRD studies. Functional groups of the title compounds have been identified from FTIR studies. Density of the grown crystals was calculated using the XRD data. Thermal stability of the samples was checked by TG/DTA studies. Mechanical and dielectric characterizations of the harvested pure and Li-doped BHP crystals reveal the mechanical strength and ferroelectric transition. The observed results are reported and discussed.

  6. Preparation, characterization, biological activity, and transport study of polystyrene based calcium-barium phosphate composite membrane.

    PubMed

    Khan, Mohammad Mujahid Ali; Rafiuddin

    2013-10-01

    Calcium-barium phosphate (CBP) composite membrane with 25% polystyrene was prepared by co-precipitation method. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transformed infrared (FTIR), and Thermogravimetric analysis (TGA) were used to characterize the membrane. The membrane was found to be crystalline in nature with consistent arrangement of particles and no indication of visible cracks. The electrical potentials measured across the composite membrane in contact with univalent electrolytes (KCl, NaCl and LiCl), have been found to increase with decrease in concentrations. Thus the membrane was found to be cation-selective. Transport properties of developed membranes may be utilized for the efficient desalination of saline water and more importantly demineralization process. The antibacterial study of this composite membrane shows good results for killing the disease causing bacteria along with waste water treatment. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Selective and effective adsorption of methyl blue by barium phosphate nano-flake.

    PubMed

    Zhang, Fan; Zhao, Zongshan; Tan, Ruiqin; Guo, Yanqun; Cao, Lujie; Chen, Liang; Li, Jia; Xu, Wei; Yang, Ye; Song, Weijie

    2012-11-15

    We report the synthesis of barium phosphate (BP) nano-flake and its adsorption behavior to methyl blue (MB) in aqueous solution. The as-obtained BP nano-flake revealed pure rhombohedral crystal structure. The adsorption capacity of MB onto BP reached 1500 mg g(-1). The adsorption equilibrium results fitted well with the Freundlich isotherm model. The adsorption process took less than 30 min to reach equilibrium. The adsorption kinetics was elucidated by the pseudo-second-order kinetic equation. It followed 2-stage and 3-stage intra-particle diffusion models for the low and high concentration of dye solutions, respectively. The adsorption of MB using the BP nano-flake was highly selective, compared with the adsorption of other dyes. The interactions between MB and BP were mainly the ionic interaction and hydrogen bonds, which were confirmed by the X-ray photoelectron spectroscopic results and the density functional theory calculations. The BP nano-flake revealed less than 5% decrease in adsorption amount when it was recycled and reused five times. The present work shows that the BP nano-flake is promising for practical applications in MB removal from aqueous solutions.

  8. Cobalt phosphate-modified barium-doped tantalum nitride nanorod photoanode with 1.5% solar energy conversion efficiency.

    PubMed

    Li, Yanbo; Zhang, Li; Torres-Pardo, Almudena; González-Calbet, Jose M; Ma, Yanhang; Oleynikov, Peter; Terasaki, Osamu; Asahina, Shunsuke; Shima, Masahide; Cha, Dongkyu; Zhao, Lan; Takanabe, Kazuhiro; Kubota, Jun; Domen, Kazunari

    2013-01-01

    Spurred by the decreased availability of fossil fuels and global warming, the idea of converting solar energy into clean fuels has been widely recognized. Hydrogen produced by photoelectrochemical water splitting using sunlight could provide a carbon dioxide lean fuel as an alternative to fossil fuels. A major challenge in photoelectrochemical water splitting is to develop an efficient photoanode that can stably oxidize water into oxygen. Here we report an efficient and stable photoanode that couples an active barium-doped tantalum nitride nanostructure with a stable cobalt phosphate co-catalyst. The effect of barium doping on the photoelectrochemical activity of the photoanode is investigated. The photoanode yields a maximum solar energy conversion efficiency of 1.5%, which is more than three times higher than that of state-of-the-art single-photon photoanodes. Further, stoichiometric oxygen and hydrogen are stably produced on the photoanode and the counter electrode with Faraday efficiency of almost unity for 100 min.

  9. Non-laxative CT colonography with barium-based faecal tagging: is additional phosphate enema beneficial and well tolerated?

    PubMed

    Davis, W; Nisbet, P; Hare, C; Cooke, P; Taylor, S A

    2011-02-01

    The purpose of this study was to investigate the efficacy and tolerance of an additional phosphate enema prior to non-laxative CT colonography (CTC). 71 patients (mean age 80 years, 28 male, 43 female) underwent non-laxative CTC following 4 oral doses of diluted 2% w/w barium sulphate. Patients were invited to self-administer a phosphate enema 2 h before CTC. An experienced observer graded the volume of retained stool (1 (nil) to 4 (>75% bowel circumference coated)), retained fluid ((1 (nil) to 4 (>50% circumference obscured)), retained stool tagging quality (1 (untagged) to 5 (≥75% to 100%) tagged) and confidence a polyp ≥6 mm could be excluded (yes/no) for each of six colonic segments. Tolerance of the enema was assessed via questionnaire. Data were analysed between those using and not using the enema by Mann-Whitney and Fisher's exact test. 18/71 patients declined the enema. There was no reduction in residual stool volume with enema use compared with non-use either overall (mean score 2.6 vs 2.7, p = 0.76) or in the left colon (mean 2.3 vs 2.4, p = 0.47). Overall tagging quality was no different (mean score 4.4 vs 4.3, p = 0.43). There was significantly more retained left colonic fluid post enema (mean score 1.9 vs 1.1, p<0.0001), and diagnostic confidence in excluding polyps was significantly reduced (exclusion not possible in 35% segments vs 21% without enema, p = 0.006). Of 53 patients, 30 (56%) found the enema straightforward to use, but 4 (8%) found it unpleasant. Phosphate enema use prior to non-laxative CTC leads to greater retained fluid, reducing diagnostic confidence, and is not recommended.

  10. Two S = 1/2 one-dimensional barium copper phosphates showing antiferromagnetic and ferromagnetic intrachain interactions.

    PubMed

    Yang, Ming; Cui, Meiyan; Zhang, Suyun; Xiang, Hongping; Guo, Wenbin; He, Zhangzhen

    2016-02-28

    Two barium copper phosphates, BaCu2(PO4)2(H2O) (1) and Ba2Cu(HPO4)(PO4)(OH) (2), were synthesized under mild hydrothermal conditions. The Cu cation in 1 adopts a CuO4(H2O) square pyramidal coordination configuration, forming alternating chains along the b axis through alternative corner and edge sharing, while the geometry of the Cu center in 2 is a CuO4(OH)2 octahedron which further connects each other by edge sharing to constitute uniform chains along the b axis. Magnetic behaviors of both compounds were analyzed by susceptibility, magnetization and heat capacity measurements. The dominant intrachain couplings are antiferromagnetic in 1 with a long-range ordering at 14 K and ferromagnetic in 2 without long-range ordering above 2 K. The first principles calculations indicate that the intrachain ferromagnetic couplings in 2 originate from Cu(1)-O(7)H-Cu(1) dpσ correlation superexchanges. The susceptibility data of compounds 1 and 2 are fitted by using suitable antiferromagnetic chain and ferromagnetic chain models, respectively. In addition, we report the results of the infrared and thermal measurements of both the compounds.

  11. Optimized Photorefractive Barium Titanate

    DTIC Science & Technology

    1992-03-11

    potassium dihydrogen phosphate (KDP), 6 and barium sodium niobate Ba2 NaNbsO%1 ,7 were examined. Unfortu- nately, the high optical intensities required for...Phys. Lett., 15, 210 (1969) 14. J. J. Amodei. D. L. Staebler. and A. W. Stephens, "Holographic Storage in Doped Barium Sodium Niobate ". Appl. Phys...equipped with precise computer control of the pulling and rotation system. The cylindrical furnace was found to be susceptible to cracking due to

  12. Barium enema

    MedlinePlus

    Lower gastrointestinal series; Lower GI series; Colorectal cancer - lower GI series; Colorectal cancer - barium enema; Crohn disease - lower GI series; Crohn disease - barium enema; Intestinal blockage - lower GI series; Intestinal blockage - ...

  13. Tantalum oxide and barium sulfate as radiopacifiers in injectable calcium phosphate-poly(lactic-co-glycolic acid) cements for monitoring in vivo degradation.

    PubMed

    Hoekstra, Jan Willem M; van den Beucken, Jeroen J J P; Leeuwenburgh, Sander C G; Bronkhorst, Ewald M; Meijer, Gert J; Jansen, John A

    2014-01-01

    Monitoring the degradation of calcium phosphate-based bone substitute materials in vivo by means of noninvasive techniques (e.g., radiography) is often a problem due to the chemical resemblance of those substitutes with the mineral phase of bone. In the view of that, the present study aimed at enhancing the radiopacity of calcium phosphate cement enriched with poly(lactic-co-glycolic acid) (CPC-PLGA) microspheres, by adding tantalum oxide (Ta2O5) or the more traditional radiopacifier barium sulfate (BaSO4). The radiopacifying capacity of these radiopacifiers was first evaluated in vitro by microcomputed tomography (μCT). Thereafter, both radiopacifiers were tested in vivo using a distal femoral condyle model in rabbits, with subsequent ex vivo μCT analysis in parallel with histomorphometry. Addition of either one of the radiopacifiers proved to enhance radiopacity of CPC-PLGA in vitro. The in vivo experiment showed that both radiopacifiers did not induce alterations in biological performance compared to plain CPC-PLGA, hence both radiopacifiers can be considered safe and biocompatible. The histomorphometrical assessment of cement degradation and bone formation showed similar values for the three experimental groups. Interestingly, μCT analysis showed that monitoring cement degradation becomes feasible upon incorporation of either type of radiopacifier, albeit that BaSO4 showed more accuracy compared to Ta2O5. Copyright © 2013 Wiley Periodicals, Inc., a Wiley Company.

  14. Barium cyanide

    Integrated Risk Information System (IRIS)

    Barium cyanide ; CASRN 542 - 62 - 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 Ef

  15. BARIUM RECOVERY PROCESS

    DOEpatents

    Blanco, R.E.

    1959-07-21

    A method of separating barium from nuclear fission products is described. In accordance with the invention, barium may be recovered from an acidic solution of neutron-irradiated fissionable material by carrying ihe barium cut of solution as a sulfate with lead as a carrier and then dissolving the barium-containing precipitate in an aqueous solution of an aliphatic diamine chelating reagent. The barium values together with certain other metallic values present in the diamine solution are then absorbed onto a cation exchange resin and the barium is selectively eluted from the resin bed with concentrated nitric acid.

  16. Barium enema (image)

    MedlinePlus

    A barium enema is performed to examine the walls of the colon. During the procedure, a well lubricated enema tube is inserted gently into the rectum. The barium, a radiopaque (shows up on X-ray) contrast ...

  17. Nucleation reduction strategy of BaNH{4}MgHPO{4} (barium ammonium magnesium hydrogen phosphate, in vitro approach-1) crystals grown in silica gel medium and its characterization studies

    NASA Astrophysics Data System (ADS)

    Suresh, P.; Kanchana, G.; Sundaramoorthi, P.

    2009-02-01

    Kidney stones consist of various organic, inorganic and semi-organic compounds. Mineral oxalate monohydrate and di-hydrate is the main inorganic constituent of kidney stones. However, the mechanisms for the formation of crystal mineral oxalate are not clearly understood. In this field of study there are many hypothesis including nucleation, crystal growth and or aggregation of formation of AOMH (ammonium oxalate monohydrate) and AODH (ammonium oxalate di-hydrate) crystals. The effect of some urinary species such as ammonium oxalates, calcium, citrate, proteins and trace mineral elements have been previously reported by the author. The kidney stone constituents are grown in the kidney environments, the sodium meta silica gel medium (SMS) provides the necessary growth simulation (in vitro). In the artificial urinary stone growth process, growth parameters within the different chemical environments are identified. The author has reported the growth of urinary crystals such as CHP, SHP, BHP and AHP. In the present study, BaNH{4}MgHPO{4} (barium ammonium magnesium hydrogen phosphate) crystals have been grown in three different growth faces to attain the total nucleation reductions. As an extension of this research, many characterization studies have been carried out and the results are reported.

  18. Two new barium indium phosphates with intersecting tunnel structures: BaIn{sub 2}P{sub 4}O{sub 14}, and Ba{sub 3}In{sub 2}P{sub 4}O{sub 16}

    SciTech Connect

    Zhang, Wei-Long; Chai, Guo-Liang; Zhang, Hao; Lin, Chen-Sheng; He, Chang-Zhen; Cheng, Wen-Dan

    2010-12-15

    Two new barium indium phosphates BaIn{sub 2}P{sub 4}O{sub 14} and Ba{sub 3}In{sub 2}P{sub 4}O{sub 16} were synthesized by high temperature solution growth method and structurally characterized by single crystal X-ray diffraction analysis. They represent first compounds in the Ba-In-P-O systems. BaIn{sub 2}P{sub 4}O{sub 14} and Ba{sub 3}In{sub 2}P{sub 4}O{sub 16} display different types of 3D architectures. The projections of both structures concern about the existence of the intersecting tunnels. In compound BaIn{sub 2}P{sub 4}O{sub 14}, the tunnels are built up of the corner-sharing InO{sub 6} octahedra and P{sub 2}O{sub 7} groups, whereas in compound Ba{sub 3}In{sub 2}P{sub 4}O{sub 16}, they are formed by corner sharing of PO{sub 4} tetrahedra and InO{sub 6} octahedra. The electronic band structure calculations of two compounds have been performed with the density functional theory method. The study of calculations and optical diffuse reflectance experimental results show both compounds are insulators with direct band-gap.

  19. Barium release system

    NASA Technical Reports Server (NTRS)

    Lewis, B. W.; Stokes, C. S.; Smith, E. W.; Murphy, W. J. (Inventor)

    1973-01-01

    A chemical system is described for releasing a good yield of free barium neutral atoms and barium ions in the upper atmosphere and interplanetary space for the study of the geophysical properties of the medium. The barium is released in the vapor phase so that it can be ionized by solar radiation and also be excited to emit resonance radiation in the visible range. The ionized luminous cloud of barium becomes a visible indication of magnetic and electrical characteristics in space and allows determination of these properties over relatively large areas at a given time.

  20. Barium bright and heavy

    NASA Astrophysics Data System (ADS)

    Fromm, Katharina M.

    2013-02-01

    Katharina M. Fromm relates how barium and its ores went from a magical, glowing species that attracted witches and alchemists to components in a variety of compounds that are key parts of modern life.

  1. Modeling and minimization of barium sulfate scale

    Treesearch

    Alan W. Rudie; Peter W. Hart

    2006-01-01

    The majority of the barium present in the pulping process exits the digester as barium carbonate. Barium carbonate dissolves in the bleach plant when the pH drops below 7 and, if barium and sulfate concentrations are too high, begins to precipitate as barium sulfate. Barium is difficult to control because a mill cannot avoid this carbonate-to-sulfate transition using...

  2. Observed Barium Emission Rates

    NASA Technical Reports Server (NTRS)

    Stenbaek-Nielsen, H. C.; Wescott, E. M.; Hallinan, T. J.

    1993-01-01

    The barium releases from the CRRES satellite have provided an opportunity for verifying theoretically calculated barium ion and neutral emission rates. Spectra of the five Caribbean releases in the summer of 1991 were taken with a spectrograph on board a U.S. Air Force jet aircraft. Because the line of sight release densities are not known, only relative rates could be obtained. The observed relative rates agree well with the theoretically calculated rates and, together with other observations, confirm the earlier detailed theoretical emission rates. The calculated emission rates can thus with good accuracy be used with photometric observations. It has been postulated that charge exchange between neutral barium and oxygen ions represents a significant source for ionization. If so. it should be associated with emissions at 4957.15 A and 5013.00 A, but these emissions were not detected.

  3. Barium and Compounds

    Integrated Risk Information System (IRIS)

    Barium and Compounds ; CASRN 7440 - 39 - 3 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 Noncarcinog

  4. Barium Peritonitis in Small Animals

    PubMed Central

    KO, Jae Jin; MANN, F. A. (Tony)

    2014-01-01

    ABSTRACT Barium peritonitis is extremely rare, but is difficult to treat and may be life-threatening. Barium suspension leakage from the gastrointestinal tract into the abdominal cavity has a time-dependent and synergistically deleterious effect in patients who have generalized bacterial peritonitis. The severity of barium peritonitis is dependent on the quantity of barium in the abdominal cavity. Barium sulfate leakage results in hypovolemia and hypoproteinemia by worsening the exudation of extracellular fluid and albumin. Abdominal fluid analysis is a useful and efficient method to diagnose barium peritonitis. Serial radiographs may not be a reliable or timely diagnostic technique. Initial aggressive fluid resuscitation and empirical broad-spectrum antibiotic treatment should be instituted promptly, followed quickly by celiotomy. During exploratory surgical intervention, copious irrigation and direct wiping with gauze are employed to remove as much barium as possible. Omentectomy should be considered when needed to expedite barium removal. Despite aggressive medical and surgical treatments, postoperative prognosis is guarded to poor due to complications, such as acute vascular shock, sepsis, diffuse peritonitis, hypoproteninemia, electrolyte imbalance, cardiac arrest, small bowel obstruction related to progression of granulomas and adhesions in the abdominal cavity. Therefore, intensive postoperative monitoring and prompt intervention are necessary to maximize chances for a positive outcome. For those that do survive, small bowel obstruction is a potential consequence due to progression of abdominal adhesions. PMID:24430662

  5. Barium uranyl diphosphonates

    SciTech Connect

    Nelson, Anna-Gay D.; Alekseev, Evgeny V.; Ewing, Rodney C.; Albrecht-Schmitt, Thomas E.

    2012-08-15

    Three Ba{sup 2+}/UO{sub 2}{sup 2+} methylenediphosphonates have been prepared from mild hydrothermal treatment of uranium trioxide, methylendiphosphonic acid (C1P2) with barium hydroxide octahydrate, barium iodate monohydrate, and small aliquots of HF at 200 Degree-Sign C. These compounds, Ba[UO{sub 2}[CH{sub 2}(PO{sub 3}){sub 2}]{center_dot}1.4H{sub 2}O (Ba-1), Ba{sub 3}[(UO{sub 2}){sub 4}(CH{sub 2}(PO{sub 3}){sub 2}){sub 2}F{sub 6}]{center_dot}6H{sub 2}O (Ba-2), and Ba{sub 2}[(UO{sub 2}){sub 2}(CH{sub 2}(PO{sub 3}){sub 2})F{sub 4}]{center_dot}5.75H{sub 2}O (Ba-3) all adopt layered structures based upon linear uranyl groups and disphosphonate molecules. Ba-2 and Ba-3 are similar in that they both have UO{sub 5}F{sub 2} pentagonal bipyramids that are bridged and chelated by the diphosphonate moiety into a two-dimensional zigzag anionic sheet (Ba-2) and a one-dimensional ribbon anionic chain (Ba-3). Ba-1, has a single crystallographically unique uranium metal center where the C1P2 ligand solely bridges to form [UO{sub 2}[CH{sub 2}(PO{sub 3}){sub 2}]{sup 2-} sheets. The interlayer space of the structures is occupied by Ba{sup 2+}, which, along with the fluoride ion, mediates the structure formed and maintains overall charge balance. - Graphical abstract: Illustration of the stacking of the layers in Ba{sub 3}[(UO{sub 2}){sub 4}(CH{sub 2}(PO{sub 3}){sub 2}){sub 2})F{sub 6}]{center_dot}6H{sub 2}O viewed along the c-axis. The structure is constructed from UO{sub 7} pentagonal bipyramidal units, U(1)O{sub 7}=gray, U(2)O{sub 7}=yellow, barium=blue, phosphorus=magenta, fluorine=green, oxygen=red, carbon=black, and hydrogen=light peach. Highlights: Black-Right-Pointing-Pointer The polymerization of the UO{sub 2}{sup 2+} sites to form uranyl dimers leads to structural variations in compounds. Black-Right-Pointing-Pointer Barium cations stitch uranyl diphosphonate anionic layers together, and help mediate structure formation. Black-Right-Pointing-Pointer HF acts as both a

  6. Constraining the oceanic barium cycle with stable barium isotopes

    NASA Astrophysics Data System (ADS)

    Cao, Zhimian; Siebert, Christopher; Hathorne, Ed C.; Dai, Minhan; Frank, Martin

    2016-01-01

    The distribution of barium (Ba) concentrations in seawater resembles that of nutrients and Ba has been widely used as a proxy of paleoproductivity. However, the exact mechanisms controlling the nutrient-like behavior, and thus the fundamentals of Ba chemistry in the ocean, have not been fully resolved. Here we present a set of full water column dissolved Ba (DBa) isotope (δ137BaDBa) profiles from the South China Sea and the East China Sea that receives large freshwater inputs from the Changjiang (Yangtze River). We find pronounced and systematic horizontal and depth dependent δ137BaDBa gradients. Beyond the river influence characterized by generally light signatures (0.0 to + 0.3 ‰), the δ137BaDBa values in the upper water column are significantly higher (+ 0.9 ‰) than those in the deep waters (+ 0.5 ‰). Moreover, δ137BaDBa signatures are essentially constant in the entire upper 100 m, in which dissolved silicon isotopes are fractionated during diatom growth resulting in the heaviest isotopic compositions in the very surface waters. Combined with the decoupling of DBa concentrations and δ137BaDBa from the concentrations of nitrate and phosphate this implies that the apparent nutrient-like fractionation of Ba isotopes in seawater is primarily induced by preferential adsorption of the lighter isotopes onto biogenic particles rather than by biological utilization. The subsurface δ137BaDBa distribution is dominated by water mass mixing. The application of stable Ba isotopes as a proxy for nutrient cycling should therefore be considered with caution and both biological and physical processes need to be considered. Clearly, however, Ba isotopes show great potential as a new tracer for land-sea interactions and ocean mixing processes.

  7. On Barium Oxide Solubility in Barium-Containing Chloride Melts

    NASA Astrophysics Data System (ADS)

    Nikolaeva, Elena V.; Zakiryanova, Irina D.; Bovet, Andrey L.; Korzun, Iraida V.

    2016-08-01

    Oxide solubility in chloride melts depends on temperature and composition of molten solvent. The solubility of barium oxide in the solvents with barium chloride content is essentially higher than that in molten alkali chlorides. Spectral data demonstrate the existence of oxychloride ionic groupings in such melts. This work presents the results of the BaO solubility in two molten BaCl2-NaCl systems with different barium chloride content. The received data together with earlier published results revealed the main regularities of BaO solubility in molten BaO-BaCl2-MCl systems.

  8. Abundance analysis of barium and mild barium stars

    NASA Astrophysics Data System (ADS)

    Smiljanic, R.; Porto de Mello, G. F.; da Silva, L.

    2007-06-01

    Aims:We compare and discuss abundances and trends in normal giants, mild barium, and barium stars, searching for differences and similarities between barium and mild barium stars that could help shed some light on the origin of these similar objects. Also, we search for nucleosynthetic effects possibly related to the s-process that were observed in the literature for elements like Cu in other types of s-process enriched stars. Methods: High signal to noise, high resolution spectra were obtained for a sample of normal, mild barium, and barium giants. Atmospheric parameters were determined from the Fe i and Fe ii lines. Abundances for Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Y, Zr, Ba, La, Ce, Nd, Sm, Eu, and Gd, were determined from equivalent widths and model atmospheres in a differential analysis, with the red giant ɛ Vir as the standard star. Results: The different levels of s-process overabundances of barium and mild barium stars were earlier suggested to be related to the stellar metallicity. Contrary to this suggestion, we found in this work no evidence of barium and mild barium having a different range in metallicity. However, comparing the ratio of abundances of heavy to light s-process elements, we found some evidence that they do not share the same neutron exposure parameter. The exact mechanism controlling this difference is still not clear. As a by-product of this analysis we identify two normal red giants misclassified as mild barium stars. The relevance of this finding is discussed. Concerning the suggested nucleosynthetic effects possibly related to the s-process, for elements like Cu, Mn, V and Sc, we found no evidence for an anomalous behavior in any of the s-process enriched stars analyzed here. However, further work is still needed since a clear [Cu/Fe] vs. [Ba/Fe] anticorrelation exists for other s-process enriched objects. Observations collected at ESO, La Silla, Chile, within the ON/ESO agreements. Tables 8-10 are only

  9. CH Stars and Barium Stars

    NASA Astrophysics Data System (ADS)

    Bond, H.; Sion, E.; Murdin, P.

    2000-11-01

    The classical barium (or `Ba II') stars are RED GIANT STARS whose spectra show strong absorption lines of barium, strontium and certain other heavy elements, as well as strong features due to carbon molecules. Together with the related class of CH stars, the Ba II stars were crucial in establishing the existence of neutron-capture reactions in stellar interiors that are responsible for the synt...

  10. Barium light source method and apparatus

    NASA Technical Reports Server (NTRS)

    Curry, John J. (Inventor); MacDonagh-Dumler, Jeffrey (Inventor); Anderson, Heidi M. (Inventor); Lawler, James E. (Inventor)

    2002-01-01

    Visible light emission is obtained from a plasma containing elemental barium including neutral barium atoms and barium ion species. Neutral barium provides a strong green light emission in the center of the visible spectrum with a highly efficient conversion of electrical energy into visible light. By the selective excitation of barium ionic species, emission of visible light at longer and shorter wavelengths can be obtained simultaneously with the green emission from neutral barium, effectively providing light that is visually perceived as white. A discharge vessel contains the elemental barium and a buffer gas fill therein, and a discharge inducer is utilized to induce a desired discharge temperature and barium vapor pressure therein to produce from the barium vapor a visible light emission. The discharge can be induced utilizing a glow discharge between electrodes in the discharge vessel as well as by inductively or capacitively coupling RF energy into the plasma within the discharge vessel.

  11. Interaction between Barium Oxide and Barium Containing Chloride Melt

    NASA Astrophysics Data System (ADS)

    Nikolaeva, Elena V.; Zakiryanova, Irina D.; Korzun, Iraida V.; Bovet, Andrey L.; Antonov, Boris D.

    2015-05-01

    Thermal analysis was applied to determine the liquidus temperatures in the NaCl-KCl-BaCl2-BaO system, with BaO concentration varied from 0 to 6 mole%. The temperature dependence of the BaO solubility in the NaCl-KCl-BaCl2 eutectic melt was investigated; the thermodynamic parameters of BaO dissolution were calculated. The caloric effects of melting of the NaCl-KCl-BaCl2 eutectic with barium oxide and barium oxychloride additions were studied. The type, morphology, and composition of oxychloride ionic groupings in the melt were determined in situ using Raman spectroscopy.

  12. Barium Stars and Thermohaline Mixing

    SciTech Connect

    Husti, Laura

    2008-01-24

    Barium stars are formed in binary systems through mass transfer from the carbon and s-element rich primary in the AGB phase, to the secondary star which is in a less evolved evolutionary stage. The mixing of the accreted material from the AGB donor with the envelope of the secondary results in a dilution of the s-element abundances. Dilution in red giants is explained by the occurence of the first dredge up, while in case of dwarfs thermohaline mixing would determine it. A comparison between the theoretical predictions of the AGB stellar models and the spectroscopical observations of a large sample of barium stars has been made. Dilution due to thermohaline mixing was taken into account when searching for best fits of the observational data. The importance of thermohaline mixing in barium dwarfs is discussed.

  13. 75 FR 33824 - Barium Chloride From China

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-15

    ... COMMISSION Barium Chloride From China Determination On the basis of the record\\1\\ developed in the subject... order on barium chloride from China would be likely to lead to continuation or recurrence of material... Barium Chloride from China: Investigation No. 731-TA-149 (Third Review). By order of the Commission...

  14. Barium hexaferrite (M-phase) exhibiting superstructure

    SciTech Connect

    Ganapathi, L.; Gopalakrishnan, J.; Rao, C.N.R.

    1984-05-01

    Barium hexaferrite (M-phase) prepared by the flux method is found to exhibit a ..sqrt..3a x ..sqrt..3a superstructure similar to barium hexaaluminate. Morgan and Shaw as well as Iyi et al have recently reported the formation of a barium-rich phase of barium hexaaluminate possessing a ..sqrt..3a x ..sqrt..3a superstructure of the magnetoplumbite structure. In view of the similarities between the layer structures of ..beta..-aluminas and the corresponding ferrites the authors have been carrying out electron microscopic investigations of potassium ..beta..-alumina and BaA1/sub 12/O/sub 19/ along with ferrites of similar compositions. They have obtained electron diffraction patterns of barium hexaaluminate identical to those obtained by Morgan and Shaw and Iyi et al, but more interestingly, they have found a phase of barium hexaferrite (M-phase) exhibiting the ..sqrt..3a x ..sqrt..3a superstructure.

  15. The problem of the barium stars

    NASA Technical Reports Server (NTRS)

    Bohm-Vitense, E.; Nemec, J.; Proffitt, C.

    1984-01-01

    Ultraviolet observations of barium stars and other cool stars with peculiar element abundances are reported. Those observations attempted to find hot white dwarf companions. Among six real barium stars studied, only Zeta Cap was found to have a white dwarf companion. Among seven mild, or marginal, barium stars studied, at least three were found to have hot subluminous companions. It is likely that all of them have white dwarf companions.

  16. Barium Depletion in Hollow Cathode Emitters

    NASA Technical Reports Server (NTRS)

    Polk, James E.; Capece, Angela M.; Mikellides, Ioannis G.; Katz, Ira

    2009-01-01

    The effect of tungsten erosion, transport and redeposition on the operation of dispenser hollow cathodes was investigated in detailed examinations of the discharge cathode inserts from an 8200 hour and a 30,352 hour ion engine wear test. Erosion and subsequent re-deposition of tungsten in the electron emission zone at the downstream end of the insert reduces the porosity of the tungsten matrix, preventing the ow of barium from the interior. This inhibits the interfacial reactions of the barium-calcium-aluminate impregnant with the tungsten in the pores. A numerical model of barium transport in the internal xenon discharge plasma shows that the barium required to reduce the work function in the emission zone can be supplied from upstream through the gas phase. Barium that flows out of the pores of the tungsten insert is rapidly ionized in the xenon discharge and pushed back to the emitter surface by the electric field and drag from the xenon ion flow. This barium ion flux is sufficient to maintain a barium surface coverage at the downstream end greater than 0.6, even if local barium production at that point is inhibited by tungsten deposits. The model also shows that the neutral barium pressure exceeds the equilibrium vapor pressure of the impregnant decomposition reaction over much of the insert length, so the reactions are suppressed. Only a small region upstream of the zone blocked by tungsten deposits is active and supplies the required barium. These results indicate that hollow cathode failure models based on barium depletion rates in vacuum dispenser cathodes are very conservative.

  17. Processing science of barium titanate

    NASA Astrophysics Data System (ADS)

    Aygun, Seymen Murat

    Barium titanate and barium strontium titanate thin films were deposited on base metal foils via chemical solution deposition and radio frequency magnetron sputtering. The films were processed at elevated temperatures for densification and crystallization. Two unifying research goals underpin all experiments: (1) To improve our fundamental understanding of complex oxide processing science, and (2) to translate those improvements into materials with superior structural and electrical properties. The relationships linking dielectric response, grain size, and thermal budget for sputtered barium strontium titanate were illustrated. (Ba 0.6Sr0.4)TiO3 films were sputtered on nickel foils at temperatures ranging between 100-400°C. After the top electrode deposition, the films were co-fired at 900°C for densification and crystallization. The dielectric properties were observed to improve with increasing sputter temperature reaching a permittivity of 1800, a tunability of 10:1, and a loss tangent of less than 0.015 for the sample sputtered at 400°C. The data can be understood using a brick wall model incorporating a high permittivity grain interior with low permittivity grain boundary. However, this high permittivity value was achieved at a grain size of 80 nm, which is typically associated with strong suppression of the dielectric response. These results clearly show that conventional models that parameterize permittivity with crystal diameter or film thickness alone are insufficiently sophisticated. Better models are needed that incorporate the influence of microstructure and crystal structure. This thesis next explores the ability to tune microstructure and properties of chemically solution deposited BaTiO3 thin films by modulation of heat treatment thermal profiles and firing atmosphere composition. Barium titanate films were deposited on copper foils using hybrid-chelate chemistries. An in-situ gas analysis process was developed to probe the organic removal and the

  18. Barium granuloma of the transverse colon.

    PubMed Central

    McKee, P. H.; Cameron, C. H.

    1978-01-01

    A case of barium sulphate granuloma of the transverse colon following gunshot wounds to the abdomen has been described. Scanning electron microscopy with electron probe microanalysis was used to confirm the presence of barium sulphate and the absence of lead or other elements related to the gunshot wounds. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:740599

  19. Phosphate salts

    MedlinePlus

    ... taken by mouth or used as enemas. Indigestion. Aluminum phosphate and calcium phosphate are FDA-permitted ingredients ... Phosphate salts containing sodium, potassium, aluminum, or calcium are LIKELY SAFE for most people when taken by mouth short-term, when sodium phosphate is inserted into the ...

  20. Radium/Barium Waste Project

    SciTech Connect

    McDowell, Allen K.; Ellefson, Mark D.; McDonald, Kent M.

    2015-06-25

    The treatment, shipping, and disposal of a highly radioactive radium/barium waste stream have presented a complex set of challenges requiring several years of effort. The project illustrates the difficulty and high cost of managing even small quantities of highly radioactive Resource Conservation and Recovery Act (RCRA)-regulated waste. Pacific Northwest National Laboratory (PNNL) research activities produced a Type B quantity of radium chloride low-level mixed waste (LLMW) in a number of small vials in a facility hot cell. The resulting waste management project involved a mock-up RCRA stabilization treatment, a failed in-cell treatment, a second, alternative RCRA treatment approach, coordinated regulatory variances and authorizations, alternative transportation authorizations, additional disposal facility approvals, and a final radiological stabilization process.

  1. Influence of Barium Hexaferrite on Magnetic Properties of Hydroxyapatite Ceramics.

    PubMed

    Jarupoom, P; Jaita, P

    2015-11-01

    Hydroxyapatite (HA) powders was derived from natural bovine bone by sequence of thermal processes. The barium hexaferrite (BF) find magnetic powders were added into HA powders in ratio of 1-3 vol.%. The HA-BF ceramics were prepared by a solid state reaction method and sintered at 1250 degrees C for 2 h. Effects of BF additive on structural, physical and magnetic properties of HA ceramics were investigated. X-ray diffraction revealed that all HA-BF samples showed a main phase of high purity hydroxyapatite [Ca10(PO4)6(OH)2] with calcium and phosphate molar ratio of 1.67. The addition of BF into HA inhibited grain growth and caused an improvement of mechanical properties. The M-H hysteresis loops also showed an improvement in magnetic behavior for higher content of BF. Moreover, in vitro bioactivity test indicated that the 2-3 vol.% sample may be suitable for biological applications.

  2. Barium Isotopes in Single Presolar Grains

    NASA Technical Reports Server (NTRS)

    Pellin, M. J.; Davis, A. M.; Savina, M. R.; Kashiv, Y.; Clayton, R. N.; Lewis, R. S.; Amari, S.

    2001-01-01

    Barium isotopic compositions of single presolar grains were measured by laser ablation laser resonant ionization mass spectrometry and the implications of the data for stellar processes are discussed. Additional information is contained in the original extended abstract.

  3. Barium Isotopes in Single Presolar Grains

    NASA Technical Reports Server (NTRS)

    Pellin, M. J.; Davis, A. M.; Savina, M. R.; Kashiv, Y.; Clayton, R. N.; Lewis, R. S.; Amari, S.

    2001-01-01

    Barium isotopic compositions of single presolar grains were measured by laser ablation laser resonant ionization mass spectrometry and the implications of the data for stellar processes are discussed. Additional information is contained in the original extended abstract.

  4. Acute barium nitrate intoxication treated by hemodialysis.

    PubMed

    Bahlmann, H; Lindwall, R; Persson, H

    2005-01-01

    A 22-year-old male was admitted to hospital with diarrhea and vomiting, cardiac arrhythmias, severe hypokalemia and gradual onset of muscular weakness. A potassium infusion was started, but for several hours serum potassium remained low. Evidence of toxic ingestion was initially lacking. When it became clear -- after a considerable delay -- that the patient had ingested barium nitrate, hemodialysis was started. This resulted in rapid clinical improvement with correction of hypokalemia and restored muscular function. Intoxication with barium causes hypokalemia, arrhythmias, muscular weakness and paralysis, often requiring respiratory support. This patient presented with symptoms typical of severe barium intoxication, non-responsive to potassium supplementation. There are few published reports on the use of hemodialysis in barium poisoning. This case confirms the possible benefit of hemodialysis in severe cases, where potassium supplementation alone is insufficient.

  5. Barium compatibility of insulator material systems

    NASA Astrophysics Data System (ADS)

    Merrill, John M.; Zee, Ralph; Schuller, Michael

    1997-01-01

    The compatibility of insulator material systems in a barium environment was investigated. This work is part of an ongoing program to identify weaknesses in insulator/braze/refractory metal materials systems which provide electrical insulation in alkali-metal enhanced thermionic devices and other alkali-metal thermal-to-electric converters. Test articles consisting of alumina or sapphire insulators brazed to molybdenum via a nominal Cu-30% Ni braze, were exposed to barium vapor to ascertain possible reactions and/or failure mechanisms. The test matrix consisted of eight samples; 5 with a sapphire insulator, 3 with an alumina insulator. Each sample was exposed to a different combination of insulator/braze region temperature (1000 K or 1100 K) and partial pressure of barium (10-3 or 10-2 torr) for approximately 750 hours. Initial analysis indicated that the ceramic portions were free from corrosion and that the braze material was the weak link in the material system. Evidence of formation of a Cu-Ba intermetallic at the braze region was visible. Further analysis indicated that in some cases Al2O3 was being reduced by the Barium. The results of this research imply that use of Al2O3 based ceramics in a barium environment may be suspect to failures in the long term and that Cu-Ni brazes are not suitable for the barium environment.

  6. Thermochemical hydrogen production via a cycle using barium and sulfur - Reaction between barium sulfide and water

    NASA Technical Reports Server (NTRS)

    Ota, K.; Conger, W. L.

    1977-01-01

    The reaction between barium sulfide and water, a reaction found in several sulfur based thermochemical cycles, was investigated kinetically at 653-866 C. Gaseous products were hydrogen and hydrogen sulfide. The rate determining step for hydrogen formation was a surface reaction between barium sulfide and water. An expression was derived for the rate of hydrogen formation.

  7. Thermochemical hydrogen production via a cycle using barium and sulfur - Reaction between barium sulfide and water

    NASA Technical Reports Server (NTRS)

    Ota, K.; Conger, W. L.

    1977-01-01

    The reaction between barium sulfide and water, a reaction found in several sulfur based thermochemical cycles, was investigated kinetically at 653-866 C. Gaseous products were hydrogen and hydrogen sulfide. The rate determining step for hydrogen formation was a surface reaction between barium sulfide and water. An expression was derived for the rate of hydrogen formation.

  8. Sulphate removal from sodium sulphate-rich brine and recovery of barium as a barium salt mixture.

    PubMed

    Vadapalli, Viswanath R K; Zvimba, John N; Mulopo, Jean; Motaung, Solly

    2013-01-01

    Sulphate removal from sodium sulphate-rich brine using barium hydroxide and recovery of the barium salts has been investigated. The sodium sulphate-rich brine treated with different dosages of barium hydroxide to precipitate barium sulphate showed sulphate removal from 13.5 g/L to less than 400 mg/L over 60 min using a barium to sulphate molar ratio of 1.1. The thermal conversion of precipitated barium sulphate to barium sulphide achieved a conversion yield of 85% using coal as both a reducing agent and an energy source. The recovery of a pure mixture of barium salts from barium sulphide, which involved dissolution of barium sulphide and reaction with ammonium hydroxide resulted in recovery of a mixture of barium carbonate (62%) and barium hydroxide (38%), which is a critical input raw material for barium salts based acid mine drainage (AMD) desalination technologies. Under alkaline conditions of this barium salt mixture recovery process, ammonia gas is given off, while hydrogen sulfide is retained in solution as bisulfide species, and this provides basis for ammonium hydroxide separation and recovery for reuse, with hydrogen sulfide also recoverable for further industrial applications such as sulfur production by subsequent stripping.

  9. Chemical abundances and kinematics of barium stars

    NASA Astrophysics Data System (ADS)

    de Castro, D. B.; Pereira, C. B.; Roig, F.; Jilinski, E.; Drake, N. A.; Chavero, C.; Sales Silva, J. V.

    2016-07-01

    In this paper, we present an homogeneous analysis of photospheric abundances based on high-resolution spectroscopy of a sample of 182 barium stars and candidates. We determined atmospheric parameters, spectroscopic distances, stellar masses, ages, luminosities and scaleheight, radial velocities, abundances of the Na, Al, α-elements, iron-peak elements, and s-process elements Y, Zr, La, Ce, and Nd. We employed the local thermodynamic equilibrium model atmospheres of Kurucz and the spectral analysis code MOOG. We found that the metallicities, the temperatures and the surface gravities for barium stars cannot be represented by a single Gaussian distribution. The abundances of α-elements and iron peak elements are similar to those of field giants with the same metallicity. Sodium presents some degree of enrichment in more evolved stars that could be attributed to the NeNa cycle. As expected, the barium stars show overabundance of the elements created by the s-process. By measuring the mean heavy-element abundance pattern as given by the ratio [s/Fe], we found that the barium stars present several degrees of enrichment. We also obtained the [hs/ls] ratio by measuring the photospheric abundances of the Ba-peak and the Zr-peak elements. Our results indicated that the [s/Fe] and the [hs/ls] ratios are strongly anticorrelated with the metallicity. Our kinematical analysis showed that 90 per cent of the barium stars belong to the thin disc population. Based on their luminosities, none of the barium stars are luminous enough to be an asymptotic giant branch star, nor to become self-enriched in the s-process elements. Finally, we determined that the barium stars also follow an age-metallicity relation.

  10. Surface treatment of barium gallogermanate laser glass

    NASA Astrophysics Data System (ADS)

    Yang, Gang; Qian, Qi; Yang, Zhongmin

    2011-01-01

    The surface of barium gallogermanate glass is modified through HCl solution etching to remove the surface defects and contaminations. The etching process and mechanism for barium gallogermanate glass in hydrochloric acid are investigated, and its optimum conditions are determined. However, the HCl etching induces the insoluble etch product containing minute crystal particles on glass surface. By heating BGG glass at the optical fiber drawing temperature, the deposited surface layer turned to be amorphous again and results in the increase of the transmittance of glass. The results indicated that the HCl etching combined with subsequent high-temperature heat treatment is an effective approach to improve the surface quality of barium gallogermanate glass, which would reduce the optical loss of the final optical fiber.

  11. Barium iodide single-crystal scintillator detectors

    NASA Astrophysics Data System (ADS)

    Cherepy, Nerine J.; Hull, Giulia; Niedermayr, Thomas R.; Drobshoff, Alexander; Payne, Stephen A.; Roy, Utpal N.; Cui, Yunlong; Bhattacharaya, Ajanta; Harrison, Melissa; Guo, Mingsheng; Groza, Michael; Burger, Arnold

    2007-09-01

    We find that the high-Z crystal Barium Iodide is readily growable by the Bridgman growth technique and is less prone to crack compared to Lanthanum Halides. We have grown Barium Iodide crystals: undoped, doped with Ce 3+, and doped with Eu 2+. Radioluminescence spectra and time-resolved decay were measured. BaI II(Eu) exhibits luminescence from both Eu 2+ at 420 nm (~450 ns decay), and a broad band at 550 nm (~3 μs decay) that we assign to a trapped exciton. The 550 nm luminescence decreases relative to the Eu 2+ luminescence when the Barium Iodide is zone refined prior to crystal growth. We also describe the performance of BaI II(Eu) crystals in experimental scintillator detectors.

  12. Improved spectrophotometric analysis of barium styphnate

    SciTech Connect

    Brown, N E; Blasi, J A

    1983-01-01

    A spectrophotometric procedure to determine the purity of barium styphnate monohydrate based upon the absorbance of the styphnate ion at 326 and 413.3 nm has been developed. The purity is determined by comparing the absorbance of the styphnate ion in barium styphnate and in styphnic acid. Our investigation has shown that the molar absorptivity and lambda maxima of the styphnate ion are quite pH dependent; therefore, the pH is buffered to 6.8 to 7.0 with ammonium acetate. Under these conditions the molar absorptivity is 1.6 x 10/sup 4/ L/mol-cm. Analyses following the procedure in the Navy specification WS13444A using water were found to give low molar absorptivities (1.3 x 10/sup 4/ L/mol-cm) for the styphnic acid calibration resulting in erroneous values for barium styphnate purity.

  13. Kinetics of photoplasma of dense barium vapour

    SciTech Connect

    Kosarev, N I

    2015-03-31

    Barium vapour ionisation under laser photoexcitation of the resonance line at a wavelength of λ = 553.5 nm is studied numerically. Seed electrons, arising due to the associative ionisation of atoms, gain energy in superelastic collisions and lead to electron avalanche ionisation of the medium. The influence of radiative transfer in a cylindrical gas volume on the excitation kinetics of barium atoms, absorption dynamics of laser radiation and oscillation of ionisation-brightening wave under competition between ionising and quenching collisions of electrons with excited atoms is studied. (interaction of laser radiation with matter)

  14. 75 FR 20625 - Barium Chloride From China

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-20

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Barium Chloride From China AGENCY: United States International Trade Commission. ACTION: Revised schedule for the subject review. DATES: Effective Date: April 9, 2010. FOR FURTHER INFORMATION CONTACT: Amy...

  15. 75 FR 19657 - Barium Chloride From China

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-15

    ... Chloride From China AGENCY: United States International Trade Commission. ACTION: Notice of Commission... China. SUMMARY: The Commission hereby gives notice that it will proceed with a full review pursuant to... antidumping duty order on barium chloride from China would be likely to lead to continuation or recurrence of...

  16. Barium Transport Process in Impregnated Dispenser Cathodes.

    DTIC Science & Technology

    1982-01-25

    Distribution of Autoelectronic Emission from Single Crystal Metal Points. II. The Adsorption, Migration and Evaporation of Thorium, Barium, and Sodium on...1966, Alkaline Earth Tungstate : Equilibrium Instability in the M-W-O Systems, J. Am. Ceram. Soc. 49, p. 385. 26 LABORAT)RY OPIRATI JS The Labratory

  17. Effects of Different Fabrication Techniques on the Yttrium-Barium-Copper Oxide High Temperature Superconductor

    DTIC Science & Technology

    1988-12-01

    lanthanum -barium-copper oxide, with a Tc of 35 K (9:1134), which was followed by a similar capound in which the lanthanum was replaced by yttrium, with a Tc...barium acetate, barium hydroxide, and barium fluoride . Barium oxide was not selected because it is not stable in air. Barium acetate was not used because...these two precursors could not be used in identical fabrication techniques. Barium fluoride was not selected because it only reacts at talperatures

  18. A detailed analysis of five barium stars

    NASA Astrophysics Data System (ADS)

    Kovacs, N.

    1985-09-01

    A model-atmosphere analysis of five barium stars is carried out, and a previous analysis of two others extended. The sample comprises types Ba 1, Ba 2, Ba 3, and Ba 5. High-resolution Reticon spectra recorded with the ESO Coude Echelle Spectrometer serve to determine abundances relative to the sun for typically 16 elements. The use of Reticon spectra improves the accuracy compared to previous analyses. Enhancements of s-process elements relative to iron by factors of 2 (HD 139195) to 30 (HD 92626) are found; neutron exposures span at least the range tau of about 0.06-0.6/mb. In the more extreme barium stars the C/O ratio is enhanced with respect to normal red giants by a factor 2.5 to 30.

  19. Nanoparticles of barium induce apoptosis in human phagocytes

    PubMed Central

    Mores, Luana; França, Eduardo Luzia; Silva, Núbia Andrade; Suchara, Eliane Aparecida; Honorio-França, Adenilda Cristina

    2015-01-01

    Purpose Nutrients and immunological factors of breast milk are essential for newborn growth and the development of their immune system, but this secretion can contain organic and inorganic toxins such as barium. Colostrum contamination with barium is an important issue to investigate because this naturally occurring element is also associated with human activity and industrial pollution. The study evaluated the administration of barium nanoparticles to colostrum, assessing the viability and functional activity of colostral mononuclear phagocytes. Methods Colostrum was collected from 24 clinically healthy women (aged 18–35 years). Cell viability, superoxide release, intracellular Ca2+ release, and phagocyte apoptosis were analyzed in the samples. Results Treatment with barium lowered mononuclear phagocyte viability, increased superoxide release, and reduced intracellular calcium release. In addition, barium increased cell death by apoptosis. Conclusion These data suggest that nanoparticles of barium in colostrum are toxic to cells, showing the importance of avoiding exposure to this element. PMID:26451108

  20. Rapid barium removal in the Delaware estuary

    SciTech Connect

    Stecher, H.A. III |; Kogut, M.B.

    1999-04-01

    Six profiles of dissolved barium covering the entire salinity range of the Delaware River and Bay estuary from March through September 1996 were collected and analyzed. The profiles are similar to one another in both shape and magnitude except for one attribute. A sudden ({le} 24 days), nearly complete (>90%) removal of dissolved Ba in midestuary occurs in mid-May followed by an 80% recovery in early June. This removal appears to be temporally and spatially coupled to the end of the spring bloom. Based on such episodic behavior, and on recent work with flocculation of diatom exudates, the authors conclude that the Ba depletion is caused by barite precipitation in the estuary during the late stages of the bloom. This would imply that lower estuary and inner coastal margin sediments associated with eutrophic estuaries receive a seasonal pulse of barite. The suddenness of this event also implies that sedimentary barite is strongly influenced by high productivity events. Comparison of the riverine Ba concentration with the effective riverine end member after desorptive barium release yields an estimated 30--40 nM Ba available from the suspended sediments as they enter the estuary. This estimate is supported by excess barium in unfiltered samples over filtered samples taken from the river and also by calculations done elsewhere.

  1. Barium hexaferrite suspensions for electrophoretic deposition.

    PubMed

    Ovtar, Simona; Lisjak, Darja; Drofenik, Miha

    2009-09-15

    In this investigation we have looked at the preparation of barium hexaferrite suspensions, with the stability of the magnetic barium hexaferrite particles being increased by the addition of a surfactant, dodecylbenzylsulfonic acid (DBSA). The influence of the solubility DBSA in different solvents and its adsorption onto the surfaces of particles with different sizes were determined from zeta-potential measurements. The most suitable and stable suspensions of barium hexaferrite particles, regardless of their sizes, were obtained in 1-butanol, and these were then used for a subsequent electrophoretic deposition. The microstructures of the deposits were examined with electron microscopy. The thickness and density of the deposits as a function of the electric field, the zeta-potential, the particle size, and the separation distance between the electrodes were investigated. The thickness of the deposits was found to increase with the increasing zeta-potential of the suspension and with the increasing separation distance between the electrodes. Denser deposits were obtained from the suspensions of smaller particles that had narrower particle size distributions.

  2. Creating unstable velocity-space distributions with barium injections

    NASA Technical Reports Server (NTRS)

    Pongratz, M. B.

    1983-01-01

    Ion velocity-space distributions resulting from barium injections from orbiting spacecraft and shaped charges are discussed. Active experiments confirm that anomalous ionization processes may operate, but photoionization accounts for the production of the bulk of the barium ions. Pitch-angle diffusion and/or velocity-space diffusion may occur, but observations of barium ions moving upwards against gravity suggests that the ions retain a significant enough fraction of their initial perpendicular velocity to provide a mirror force. The barium ion plasmas should have a range of Alfven Mach numbers and plasma betas. Because the initial conditions can be predicted these active experiments should permit testing plasma instability hypotheses.

  3. Lanthanide doped strontium-barium cesium halide scintillators

    DOEpatents

    Bizarri, Gregory; Bourret-Courchesne, Edith; Derenzo, Stephen E.; Borade, Ramesh B.; Gundiah, Gautam; Yan, Zewu; Hanrahan, Stephen M.; Chaudhry, Anurag; Canning, Andrew

    2015-06-09

    The present invention provides for a composition comprising an inorganic scintillator comprising an optionally lanthanide-doped strontium-barium, optionally cesium, halide, useful for detecting nuclear material.

  4. Binding and leakage of barium in alginate microbeads.

    PubMed

    Mørch, Yrr A; Qi, Meirigeng; Gundersen, Per Ole M; Formo, Kjetil; Lacik, Igor; Skjåk-Braek, Gudmund; Oberholzer, Jose; Strand, Berit L

    2012-11-01

    Microbeads of alginate crosslinked with Ca(2+) and/or Ba(2+) are popular matrices in cell-based therapy. The aim of this study was to quantify the binding of barium in alginate microbeads and its leakage under in vitro and accumulation under in vivo conditions. Low concentrations of barium (1 mM) in combination with calcium (50 mM) and high concentrations of barium (20 mM) in gelling solutions were used for preparation of microbeads made of high-G and high-M alginates. High-G microbeads accumulated barium from gelling solution and contained higher concentrations of divalent ions for both low- and high-Ba exposure compared with high-G microbeads exposed to calcium solely and to high-M microbeads for all gelling conditions. Although most of the unbound divalent ions were removed during the wash and culture steps, leakage of barium was still detected during storage. Barium accumulation in blood and femur bone of mice implanted with high-G beads was found to be dose-dependent. Estimated barium leakage relevant to transplantation to diabetic patients with islets in alginate microbeads showed that the leakage was 2.5 times lower than the tolerable intake value given by WHO for high-G microbeads made using low barium concentration. The similar estimate gave 1.5 times higher than is the tolerable intake value for the high-G microbeads made using high barium concentration. To reduce the risk of barium accumulation that may be of safety concern, the microbeads made of high-G alginate gelled with a combination of calcium and low concentration of barium ions is recommended for islet transplantation.

  5. 40 CFR 721.10011 - Barium calcium manganese strontium oxide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Barium calcium manganese strontium... Specific Chemical Substances § 721.10011 Barium calcium manganese strontium oxide. (a) Chemical substance... manganese strontium oxide (PMN P-00-1124; CAS No. 359427-90-0) is subject to reporting under this section...

  6. 40 CFR 721.10011 - Barium calcium manganese strontium oxide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Barium calcium manganese strontium... Specific Chemical Substances § 721.10011 Barium calcium manganese strontium oxide. (a) Chemical substance... manganese strontium oxide (PMN P-00-1124; CAS No. 359427-90-0) is subject to reporting under this section...

  7. 40 CFR 721.10011 - Barium calcium manganese strontium oxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Barium calcium manganese strontium... Specific Chemical Substances § 721.10011 Barium calcium manganese strontium oxide. (a) Chemical substance... manganese strontium oxide (PMN P-00-1124; CAS No. 359427-90-0) is subject to reporting under this section...

  8. 40 CFR 721.10011 - Barium calcium manganese strontium oxide.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Barium calcium manganese strontium... Specific Chemical Substances § 721.10011 Barium calcium manganese strontium oxide. (a) Chemical substance... manganese strontium oxide (PMN P-00-1124; CAS No. 359427-90-0) is subject to reporting under this...

  9. Acute barium intoxication following ingestion of ceramic glaze.

    PubMed

    Thomas, M; Bowie, D; Walker, R

    1998-09-01

    A case of deliberate overdose of barium sulphide in a psychiatric setting is presented, with resulting flaccid paralysis, malignant arrhythmia, respiratory arrest and severe hypokalaemia, but ultimately with complete recovery. The degree of paralysis appears to be related directly to serum barium levels. The value of early haemodialysis, particularly with respiratory paralysis and hypokalaemia, is emphasised.

  10. Barium strontium titanate powder obtained by polymeric precursor method

    SciTech Connect

    Ries, A.; Simoes, A.Z.; Cilense, M.; Zaghete, M.A.; Varela, J.A

    2003-03-15

    Pure barium strontium titanate powder, with Ba/Sr ratio of 80/20 was prepared by the polymeric precursor method (also called Pechini process). The powder was obtained after a calcination at 800 deg. C for 8 h and characterized by XRD, IR, BET and SEM. The requirements to avoid barium carbonate as a secondary phase are presented and discussed in detail.

  11. 40 CFR 721.10011 - Barium calcium manganese strontium oxide.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Barium calcium manganese strontium... Specific Chemical Substances § 721.10011 Barium calcium manganese strontium oxide. (a) Chemical substance... manganese strontium oxide (PMN P-00-1124; CAS No. 359427-90-0) is subject to reporting under this...

  12. Production of translationally cold barium monohalide ions

    NASA Astrophysics Data System (ADS)

    DePalatis, M. V.; Chapman, M. S.

    2013-08-01

    We have produced sympathetically cooled barium monohalide ions BaX+ (X=F, Cl, Br) by reacting trapped, laser-cooled Ba+ ions with room-temperature gas-phase neutral halogen-containing molecules. Reaction rates for two of these (SF6 and CH3Cl) have been measured and were found to be in agreement with classical models. BaX+ ions are promising candidates for cooling to the rovibrational ground state, and our method presents a straightforward way to produce these polar molecular ions.

  13. Anisotropic thermal expansion of strontium barium niobate

    NASA Astrophysics Data System (ADS)

    Qadri, Syed B.; Bellotti, Jeffrey A.; Garzarella, Anthony; Wu, Dong Ho

    2005-06-01

    Strontium barium niobate is a tungsten-bronze ferroelectric crystal having a tetragonal unit cell. Low-temperature x-ray diffraction studies were performed on a single crystal of Sr0.75Ba0.25Nb2O6 to determine the thermal expansivity along the a- and c-axes. Negative thermal expansion was observed along the c direction while a positive thermal expansion was measured along the a axis. The anisotropic thermal expansion behavior is explained as arising due to the geometry of the crystal structure.

  14. Short-cavity squeezing in barium

    NASA Technical Reports Server (NTRS)

    Hope, D. M.; Bachor, H-A.; Manson, P. J.; Mcclelland, D. E.

    1992-01-01

    Broadband phase sensitive noise and squeezing were experimentally observed in a system of barium atoms interacting with a single mode of a short optical cavity. Squeezing of 13 +/- 3 percent was observed. A maximum possible squeezing of 45 +/- 8 percent could be inferred for out experimental conditions, after correction for measured loss factors. Noise reductions below the quantum limit were found over a range of detection frequencies 60-170 MHz and were best for high cavity transmission and large optical depths. The amount of squeezing observed is consistent with theoretical predictions from a full quantum statistical model of the system.

  15. Europium-doped barium bromide iodide

    SciTech Connect

    Gundiah, Gautam; Hanrahan, Stephen M.; Hollander, Fredrick J.; Bourret-Courchesne, Edith D.

    2009-10-21

    Single crystals of Ba0.96Eu0.04BrI (barium europium bromide iodide) were grown by the Bridgman technique. The title compound adopts the ordered PbCl2 structure [Braekken (1932). Z. Kristallogr. 83, 222-282]. All atoms occupy the fourfold special positions (4c, site symmetry m) of the space group Pnma with a statistical distribution of Ba and Eu. They lie on the mirror planes, perpendicular to the b axis at y = +-0.25. Each cation is coordinated by nine anions in a tricapped trigonal prismatic arrangement.

  16. Vacancy ordering in reduced barium titanate

    NASA Astrophysics Data System (ADS)

    Woodward, David I.; Reaney, Ian M.; Yang, Gaiying Y.; Dickey, Elizabeth C.; Randall, Clive A.

    2004-06-01

    A crystal structure is proposed for reduced barium titanate, BaTiO3-δ, δ≈0.33, formed during the degradation of Ni-BaTiO3 X7R multilayer ceramic capacitors. High-resolution transmission electron microscopy and selected-area electron diffraction have been used in combination with computer simulations to show that oxygen vacancies accrete on every third pseudocubic {111} plane, resulting in a cell with space group P3m1. Additionally, from electron energy loss spectroscopy, it is proposed that Ti4+ is reduced to Ti3+ as a mechanism of charge compensation within oxygen-deficient octahedra.

  17. Barium appendicitis: A single institution review in Japan

    PubMed Central

    Katagiri, Hideki; Lefor, Alan Kawarai; Kubota, Tadao; Mizokami, Ken

    2016-01-01

    AIM To review clinical experience with barium appendicitis at a single institution. METHODS A retrospective review of patients admitted with a diagnosis of acute appendicitis, from January 1, 2013 to December 31, 2015 was performed. Age, gender, computed tomography (CT) scan findings if available, past history of barium studies, pathology, and the presence of perforation or the development of complications were reviewed. If the CT scan revealed high density material in the appendix, the maximum CT scan radiodensity of the material is measured in Hounsfield units (HU). Barium appendicitis is defined as: (1) patients diagnosed with acute appendicitis; (2) the patient has a history of a prior barium study; and (3) the CT scan shows high density material in the appendix. Patients who meet all three criteria are considered to have barium appendicitis. RESULTS In total, 396 patients were admitted with the diagnosis of acute appendicitis in the study period. Of these, 12 patients (3.0%) met the definition of barium appendicitis. Of these 12 patients, the median CT scan radiodensity of material in the appendix was 10000.8 HU, ranging from 3066 to 23423 HU (± 6288.2). In contrast, the median CT scan radiodensity of fecaliths in the appendix, excluding patients with barium appendicitis, was 393.1 HU, ranging from 98 to 2151 HU (± 382.0). The CT scan radiodensity of material in the appendices of patients with barium appendicitis was significantly higher than in patients with nonbarium fecaliths (P < 0.01). CONCLUSION Barium appendicitis is not rare in Japan. Measurement of the CT scan radiodensity of material in the appendix may differentiate barium appendicitis from routine appendicitis. PMID:27721929

  18. Barium sulfate aspiration: Severe chemical pneumonia induced by a massive reflux of contrast medium during small bowel barium enema.

    PubMed

    Zhang, Lin; Yang, Yi; Zhang, Ji; Zhou, Xiaowei; Dong, Hongmei; Zhou, Yiwu

    2015-08-01

    Barium contrast radiography is a conventional procedure aimed at revealing lesions of the alimentary tract using barium sulfate on X-ray irradiation. Although it is widely used in clinics, adverse effects and complications are observed, such as anaphylaxis, granuloma, fecalithes, abdomen-leaking, embolism, bacterial contamination, and aspiration. We report a case of death due to a massive barium sulfate aspiration resulted from an air-barium double contrast enema radiography. A 25-year-old female patient was hospitalized with symptoms of abdominal distention, nausea, vomiting and diarrhea for three days. A progressive respiratory distress presented only 1h after a small bowel air-barium double contrast enema. The patient died 11h later. The result of autopsy revealed the cause of death to be severe chemical pneumonitis induced by gastric fluid which was aspirated into her lungs. Barium sulfate is generally recognized to be chemically inert for the respiratory system, but a mixture of barium sulfate with gastric contents is fatal. Here we intend to suggest that, when determining the potential cause of death, medical examiners should consider a patient's status quo as well as the possible adverse effects and complications caused by the barium sulfate preparation during gastrointestinal radiography.

  19. Barium toxicity effects in soybean plants.

    PubMed

    Suwa, Ryuichi; Jayachandran, Krish; Nguyen, Nguyen Tran; Boulenouar, Abdellah; Fujita, Kounosuke; Saneoka, Hirofumi

    2008-10-01

    Barium (Ba)-induced phytotoxicity at 100, 1000, or 5000 microM Ba in soybean plants (Glycine max) was investigated under hydroponic culture conditions. Soybean growth and leaf photosynthetic activity were significantly inhibited by all three levels of Ba treatments. In the case of photosynthetic activity, 5000 microM Ba treatment shutdown stomatal opening and perturbed carbon fixation metabolism and translocation. However, 100 and 1000 microM Ba treatments shut down stomatal opening and inhibited carbon fixation, but without perturbation of leaf carbon fixation-related metabolism. Potassium (K) absorption by soybean roots was also reduced in all three Ba treatments. This decreased K absorption reduced K localization at guard cells. Barium accumulation in guard cells also inhibited K transport from epidermal cells to guard cells. This lack of K in guard cells resulted in stomatal closure. As a result of inhibition of K transport into guard cells and stomatal shutdown, photosynthetic activity and plant productivity were inhibited. Our experiment indicates that Ba has phytotoxic effects on soybean plants by inhibiting photosynthesis.

  20. Deflocculants for Tape Casting Barium Titanate.

    DTIC Science & Technology

    1983-07-01

    acid . In terms of Bronsted - Lowry acid - base reactions, the phosphate ester donates a proton and is...potentiometric non- aqueous titration of the acid by a base was considered feasible. 0 However, the equilibrium concentration of the acid proved to be too...addition of the phosphate ester. Dissociation can be represented by a Lewis acid - base reaction. - 30 O H PHOSPHORIC ACID ON OR OR HO 11 -R

  1. Do all barium stars have a white dwarf companion?

    NASA Technical Reports Server (NTRS)

    Dominy, J. F.; Lambert, D. L.

    1983-01-01

    International Ultraviolet Explorer short-wavelength, low-dispersion spectra were analyzed for four barium, two mild barium, and one R-type carbon star in order to test the hypothesis that the barium and related giants are produced by mass transfer from a companion now present as a white dwarf. An earlier tentative identification of a white dwarf companion to the mild barium star Zeta Cyg is confirmed. For the other stars, no ultraviolet excess attributable to a white dwarf is seen. Limits are set on the bolometric magnitude and age of a possible white dwarf companion. Since the barium stars do not have obvious progenitors among main-sequence and subgiant stars, mass transfer must be presumed to occur when the mass-gaining star is already on the giant branch. This restriction, and the white dwarf's minimum age, which is greater than 8 x 10 to the 8th yr, determined for several stars, effectively eliminates the hypothesis that mass transfer from an asymptotic giant branch star creates a barium star. Speculations are presented on alternative methods of producing a barium star in a binary system.

  2. Hygienic importance of increased barium content in some fresh waters.

    PubMed

    Havlík, B; Hanusová, J; Rálková, J

    1980-01-01

    In surface waters of the mining and processing areas of uranium ore there is an increased content of free and bound barium ions due to the use of barium salts for the treatment of waste and mine waters containing radium. In model experiments with the algae Ankistrodesmus falcatus, Chlorella kessleri and Scenedesmus obliquus, we studied the effect of Ba2+ on the accumulation of 226Ra. It was found that the accumulation of radium by algae is negatively influenced with barium concentrations higher than 1 mg.l-1. The accumulation of barium of organisms of primary production was studied using 133BaCl2. At a barium content in the medium of 4.0, 0.46 and 0.04 mu. l-1, the algae accumulated 30-60% of the added amount of barium during an exposure of 15 days. Biochemical analyses showed that barium is bound to the cellular membrane and to other components of the algal cell that cannot be extracted with water or alcohol.

  3. Microstructure and magnetism in barium strontium titanate (BSTO)-barium hexaferrite (BaM) multilayers

    SciTech Connect

    Frey, N.A.; Heindl, R.; Srinath, S.; Srikanth, H. . E-mail: sharihar@cas.usf.edu; Dudney, N.J.

    2005-08-11

    High quality multilayers of barium ferrite (BaM) and barium strontium titanate (BSTO) were grown in optimized conditions on thermally oxidized Si(1 0 0) and Al{sub 2}O{sub 3} substrates using magnetron sputtering. As-grown films were amorphous and different annealing procedures were explored to stabilize crystalline phases. BSTO and BaM phases were identified using X-ray diffraction and cross-sectional scanning electron micrographs showed sharp interfaces between BSTO and BaM layers. Magnetic hysteresis loops obtained at various temperatures and field orientations showed a large coercivity ({approx}2500 Oe) consistent with the hard magnetic hexaferrite component. Hysteresis loops also revealed the distinct influence of magnetocrystalline and shape anisotropies at different temperature ranges.

  4. Proton conductivity of potassium doped barium zirconates

    SciTech Connect

    Xu Xiaoxiang; Tao Shanwen; Irvine, John T.S.

    2010-01-15

    Potassium doped barium zirconates have been synthesized by solid state reactions. It was found that the solubility limit of potassium on A-sites is between 5% and 10%. Introducing extra potassium leads to the formation of second phase or YSZ impurities. The water uptake of barium zirconates was increased even with 5% doping of potassium at the A-site. The sintering conditions and conductivity can be improved significantly by adding 1 wt% ZnO during material synthesis. The maximum solubility for yttrium at B-sites is around 15 at% after introducing 1 wt% zinc. The conductivity of Ba{sub 0.95}K{sub 0.05}Zr{sub 0.85}Y{sub 0.11}Zn{sub 0.04}O{sub 3-{delta}} at 600 deg. C is 2.2x10{sup -3} S/cm in wet 5% H{sub 2}. The activation energies for bulk and grain boundary are 0.29(2), 0.79(2) eV in wet 5% H{sub 2} and 0.31(1), 0.74(3) eV in dry 5% H{sub 2}. A power density of 7.7 mW/cm{sup 2} at 718 deg. C was observed when a 1 mm thick Ba{sub 0.95}K{sub 0.05}Zr{sub 0.85}Y{sub 0.11}Zn{sub 0.04}O{sub 3-{delta}} pellet was used as electrolyte and platinum electrodes. - Graphical abstract: Potassium doped barium zirconates have been synthesized by solid state reactions. It was found that the solubility limit of potassium on A-sites is between 5% and 10 %. The sintering conditions and conductivity can be improved significantly by adding 1 wt% ZnO during material synthesis. Five percent doping of potassium at A-site can double the total conductivity.

  5. A high-altitude barium radial injection experiment

    NASA Technical Reports Server (NTRS)

    Wescott, E. M.; Stenbaek-Nielsen, H. C.; Hallinan, T. J.; Deehr, C. S.; Romick, G. J.; Olson, J. V.; Roederer, J. G.; Sydora, R.

    1980-01-01

    A rocket launched from Poker Flat, Alaska, carried a new type of high-explosive barium shaped charge to 571 km, where detonation injected a thin disk of barium vapor with high velocity nearly perpendicular to the magnetic field. The TV images of the injection are spectacular, revealing three major regimes of expanding plasma which showed early instabilities in the neutral gas. The most unusual effect of the injection is a peculiar rayed barium-ion structure lying in the injection plane and centered on a 5 km 'black hole' surrounding the injection point. Preliminary electrostatic computer simulations show a similar rayed development.

  6. Metallurgical Properties and Phase Transformations of Barium-Strontium Modifier

    NASA Astrophysics Data System (ADS)

    Platonov, M. A.; Sulimova, I. S.; Rozhikhina, I. D.; Dmitrienko, V. I.; Horoshun, G. V.

    2016-04-01

    Metallurgical properties and phase transformations of barium-strontium modifier were tested in laboratory conditions resembling steel processing in furnace and ladle. When heating barium-strontium modifier start of melting, kinetics of decomposition, phase and structure transformation were studied. The concentrate under consideration has been revealed to be a complex mineral compound containing barytocalcite, calcite, calciostrontianite, dolomite and siderite. The reaction kinetics of decomposing mineral components of barium-strontium modifier to oxides does not considerably affect slag formation in conditions of out-of-furnace steel processing.

  7. Short-term effects of intratracheal installations of yttrium barium copper oxide

    SciTech Connect

    London, J.E.; Newkirk, L.R.; Lehnert, B.E.

    1990-12-01

    Inhalation exposures to the new high-temperature ({Tc}) superconductor (SC) materials can occur during manufacturing and fabrication processes. In this exploratory study, we examined the pulmonary response to the deposition of an yttrium barium copper oxide SC powder. Groups of Sprague-Dawley rats were intratracheally instilled with either 10 mg or 20 mg of SC in phosphate-buffered saline (PBS) or with PBS only. The animals were sacrificed 60 days later for histopathologic assessments of their lungs. Lung lesions in the 10-mg SC group were found mainly in alveolar ducts and proximal alveoli. The lesions consisted of variably sized foci of interstitial thickening involving accumulations of macrophages. These interstitial aggregates were often times centered around one or more extracellular crystals, which, presumably, were retained SC product. Trichome stains also demonstrated the presence of fibrosis in the walls of alveoli surrounding the granulomas. Similar interstitial-macrophage accumulations and fibrosis were observed in rats instilled with 20 mg of SC. However, alveolus like structures lined by ciliated cuboidal epithelium near interstitial granulomas were additionally found in the lungs of some of the animals in this latter group. These results suggest SC material of the yttrium barium copper oxide type may represent a potential exposure hazard to the lung.

  8. Barium carbonate catalysis of carbon gasification

    SciTech Connect

    Ersolmaz, C.; Falconer, J.L.

    1985-01-01

    The interaction of barium carbonate with carbon black was studied to understand catalyzed CO/sub 2/ gasification of carbon. Temperature-programmed reaction with isotopic labeling of the carbonate and the carbon showed that carbon dramatically accelerated with rate of BaCO/sub 3/ decomposition to form BaO and CO/sub 2/, which rapidly gasified carbon to form CO. Pure BaCO/sub 3/ was observed to exchange carbon dioxide with the gas-phase, and the exchange rate was significantly increased by carbon at higher temperatures, due to formation of a carbon-carbonate complex. The interaction of BaCO/sub 3/ and C to form a complex occurred well below gasification temperatures, and BaCO/sub 3/ did not decompose until after gasification began and the gas phase CO/sub 2/ concentration was low.

  9. Solar Twins and the Barium Puzzle

    NASA Astrophysics Data System (ADS)

    Reddy, Arumalla B. S.; Lambert, David L.

    2017-08-01

    Several abundance analyses of Galactic open clusters (OCs) have shown a tendency for Ba but not for other heavy elements (La-Sm) to increase sharply with decreasing age such that Ba was claimed to reach [Ba/Fe] ≃ +0.6 in the youngest clusters (ages < 100 Myr) rising from [Ba/Fe] = 0.00 dex in solar-age clusters. Within the formulation of the s-process, the difficulty to replicate higher Ba abundance and normal La-Sm abundances in young clusters is known as the barium puzzle. Here, we investigate the barium puzzle using extremely high-resolution and high signal-to-noise spectra of 24 solar twins and measured the heavy elements Ba, La, Ce, Nd, and Sm with a precision of 0.03 dex. We demonstrate that the enhanced Ba ii relative to La-Sm seen among solar twins, stellar associations, and OCs at young ages (<100 Myr) is unrelated to aspects of stellar nucleosynthesis but has resulted from overestimation of Ba by standard methods of LTE abundance analysis in which the microturbulence derived from the Fe lines formed deep in the photosphere is insufficient to represent the true line broadening imposed on Ba ii lines by the upper photospheric layers from where the Ba ii lines emerge. Because the young stars have relatively active photospheres, Ba overabundances most likely result from the adoption of a too low value of microturbulence in the spectrum synthesis of the strong Ba ii lines but the change of microturbulence in the upper photosphere has only a minor affect on La-Sm abundances measured from the weak lines.

  10. A triangular heterometallic siloxide containing barium

    SciTech Connect

    Coan, P.S.; Streib, W.E.; Caulton, K.G. )

    1991-12-25

    Reaction of KOSiPh[sub 3] with Ba[sub 3](OSiPh[sub 3])[sub 6](THF) in THF displaces barium from the triangular reagent to yield a colorless solid. Recrystallization in the presence of MeOC[sub 2]H[sub 4]OMe(DME) yields KBa[sub 2](OSiPh[sub 3])[sub 5](DME)[sub 2], characterized by [sup 1]H and [sup 29]Si NMR spectroscopy and X-ray diffraction. The molecule contains a triangular KBa[sub 2]([mu][sub 3]-OSiPh[sub 3])[sub 2]([mu][sub 2]-OSiPh[sub 3])[sub 3] core with [eta][sup 1] and [eta][sup 2]-DME ligation on each barium. The benzene-soluble molecule is fluxional in solution at both the OSiPh[sub 3] and the DME groups. At -70C in CH[sub 2]Cl[sub 2]/C[sub 6]D[sub 6], both [eta][sup 1]-DME/[eta][sup 2]-DME site exchange and intramolecular siloxide migration have been slowed, and the spectra are in agreement with retention of the solid-state structure in solution. Crystallographic data for KBa[sub 2](OSiPh[sub 3])[sub 5](DME)[sub 2] (-159C): a = 15.474 (3) [angstrom], b = 26.466 (6) [angstrom], c = 23.783 (5) [angstrom], [beta] = 99.80 (1)[degree] with Z = 4 in space group P2[sub 1]/n.

  11. Phased surgical treatment of barium enema-induced rectal injury and retention of barium in the pelvic floor space

    PubMed Central

    Yang, Xuefei; Xia, Ligang; Huang, Jun; Wang, Jianping

    2014-01-01

    Iatrogenic injuries caused by barium enema are rarely reported. Following a phased surgical protocol for up to one year, we have successfully treated a patient with rectal injury and severe infection of the pelvic floor space complicated with retention of large amounts of barium and vaginal fistula. In this article, the phased surgery planning for the treatment of rectal injury complicated with vaginal fistula is discussed in terms of the pros and cons, and the observed effect and evolution of barium retained in the pelvic floor space are described. PMID:25405155

  12. Upper gastrointestinal barium evaluation of duodenal pathology: A pictorial review

    PubMed Central

    Gupta, Pankaj; Debi, Uma; Sinha, Saroj Kant; Prasad, Kaushal Kishor

    2014-01-01

    Like other parts of the gastrointestinal tract (GIT), duodenum is subject to a variety of lesions both congenital and acquired. However, unlike other parts of the GIT viz. esophagus, rest of the small intestine and large intestine, barium evaluation of duodenal lesions is technically more challenging and hence not frequently reported. With significant advances in computed tomography technology, a thorough evaluation including intraluminal, mural and extramural is feasible in a single non-invasive examination. Notwithstanding, barium evaluation still remains the initial and sometimes the only imaging study in several parts of the world. Hence, a thorough acquaintance with the morphology of various duodenal lesions on upper gastrointestinal barium examination is essential in guiding further evaluation. We reviewed our experience with various common and uncommon barium findings in duodenal abnormalities. PMID:25170399

  13. Study of the photovoltaic effect in thin film barium titanate

    NASA Technical Reports Server (NTRS)

    Grannemann, W. W.; Dharmadhikari, V. S.

    1983-01-01

    The feasibility of making non-volatile digital memory devices of barium titanate, BaTiO3, that are integrated onto a silicon substrate with the required ferroelectric film produced by processing, compatible with silicon technology was examined.

  14. Calculated emission rates for barium releases in space

    NASA Technical Reports Server (NTRS)

    Stenbaek-Nielsen, H. C.

    1989-01-01

    The optical emissions from barium releases in space are caused by resonance and fluorescent scattering of sunlight. Emission rates for the dominant ion and neutral lines are calculated assuming the release to be optically thin and the barium to be in radiative equilibrium with the solar radiation. The solar spectrum has deep Fraunhofer absorption lines at the primary barium ion resonances. A velocity component toward or away from the sun will Doppler shift the emission lines relative to the absorption lines and the emission rates will increase many-fold over the rest value. The Doppler brightening is important in shaped charge or satellite releases where the barium is injected at high velocities. Emission rates as a function of velocity are calculated for the 4554, 4934, 5854, 6142 and 6497 A ion emission lines and the dominant neutral line at 5535 A. Results are presented for injection parallel to the ambient magnetic field, B, and for injection at an angle to B.

  15. Synthesis, photoluminescence and magnetic properties of barium vanadate nanoflowers

    SciTech Connect

    Xu, Jing; Hu, Chenguo; Xi, Yi; Peng, Chen; Wan, Buyong; He, Xiaoshan

    2011-06-15

    Graphical abstract: The flower-shaped barium vanadate was obtained for the first time. The photoluminescence and magnetic properties of the barium vanadate nanoflowers were investigated at room temperature. Research highlights: {yields} In the paper, the flower-shaped barium vanadate were obtained for the first time. The CHM method used here is new and simple for preparation of barium vanadate. {yields} The photoluminescence and magnetic properties of the barium vanadate nanoflowers were investigated at room temperature. The strong bluish-green emission was observed. {yields} The ferromagnetic behavior of the barium vanadate nanoflowers was found with saturation magnetization of about 83.50 x 10{sup -3} emu/g, coercivity of 18.89 Oe and remnant magnetization of 4.63 x 10{sup -3} emu/g. {yields} The mechanisms of PL and magnetic property of barium vanadate nanoflowers have been discussed. -- Abstract: The flower-shaped barium vanadate has been obtained by the composite hydroxide mediated (CHM) method from V{sub 2}O{sub 5} and BaCl{sub 2} at 200 {sup o}C for 13 h. XRD and XPS spectrum of the as-synthesized sample indicate it is hexagonal Ba{sub 3}V{sub 2}O{sub 8} with small amount of Ba{sub 3}VO{sub 4.8} coexistence. Scan electron microscope and transmission electron microscope display that the flower-shaped crystals are composed of nanosheets with thickness of {approx}20 nm. The UV-visible spectrum shows that the barium vanadate sample has two optical gaps (3.85 eV and 3.12 eV). Photoluminescence spectrum of the barium vanadate flowers exhibits a visible light emission centered at 492 and 525 nm which might be attributed to VO{sub 4} tetrahedron with T{sub d} symmetry in Ba{sub 3}V{sub 2}O{sub 8}. The ferromagnetic behavior of the barium vanadate nanoflowers has been found with saturation magnetization of about 83.50 x 10{sup -3} emu/g, coercivity of 18.89 Oe and remnant magnetization of 4.63 x 10{sup -3} emu/g, which is mainly due to the presence of a non

  16. Coastal barium cycling at the West Antarctic Peninsula

    NASA Astrophysics Data System (ADS)

    Pyle, K. M.; Hendry, K. R.; Sherrell, R. M.; Meredith, M. P.; Venables, H.; Lagerström, M.; Morte-Ródenas, A.

    2017-05-01

    Barium cycling in the ocean is associated with a number of processes, including the production and recycling of organic matter, freshwater fluxes, and phenomena that affect alkalinity. As a result, the biogeochemical cycle of barium offers insights into past and present oceanic conditions, with barium currently used in various forms as a palaeoproxy for components of organic and inorganic carbon storage, and as a quasi-conservative water mass tracer. However, the nature of the oceanic barium cycle is not fully understood, particularly in cases where multiple processes may be interacting simultaneously with the dissolved and particulate barium pools. This is particularly the case in coastal polar regions such as the West Antarctic Peninsula, where biological drawdown and remineralisation occur in tandem with sea ice formation and melting, glacial meltwater input, and potential fluxes from shelf sediments. Here, we use a high-precision dataset of dissolved barium (Bad) from a grid of stations adjacent to the West Antarctic Peninsula in conjunction with silicic acid (Si(OH)4), the oxygen isotope composition of water, and salinity measurements, to determine the relative control of various coastal processes on the barium cycle throughout the water column. There is a strong correlation between Bad and Si(OH)4 present in deeper samples, but nevertheless persists significantly in surface waters. This indicates that the link between biogenic opal and barium is not solely due to barite precipitation and dissolution at depth, but is supplemented by an association between Bad and diatom tests in surface waters, possibly due to barite formation within diatom-dominated phytodetritus present in the photic zone. Sea-ice meltwater appears to exert a significant secondary control on barium concentrations, likely due to non-conservative biotic or abiotic processes acting as a sink for Bad within the sea ice itself, or sea-ice meltwater stimulating non-siliceous productivity that acts

  17. A search for technetium (Tc II) in barium stars

    NASA Technical Reports Server (NTRS)

    Little-Marenin, Irene R.; Little, Stephen J.

    1987-01-01

    The authors searched without success for the lines of Tc II at 2647.02, 2610.00 and 2543.24 A in IUE spectra of the barium stars HR 5058, Omicron Vir, and Zeta Cap. The lack of Tc II implies that the observed s-process enhancements were produced more than half a million years ago and supports the suggestion that the spectral peculiarities of barium stars are probably related to the binary nature of the stars.

  18. Solar eclipse sign of intussusception on barium enema.

    PubMed

    Raveenthiran, V

    2002-01-01

    The colographic appearance of intussusception is variously described as a claw sign, pincer defect, shouldering effect, and coiled-spring pattern. This report adds a new radiographic sign to the list. An end-on view of an intussusception on barium enema shows a ring of contrast resembling a solar eclipse. Familiarity with this bizarre appearance is desirable, lest it may be mistaken for spillage of barium due to a colonic perforation.

  19. 'Skidding' of the CRRES G-9 barium release

    NASA Technical Reports Server (NTRS)

    Huba, J. D.; Mitchell, H. G.; Fedder, J. A.; Bernhardt, P. A.

    1992-01-01

    A simulation study and experimental data of the CRRES G-9 ionospheric barium release are presented. The simulation study is based on a 2D electrostatic code that incorporates time-dependent coupling to the background plasma. It is shown that the densest portion of the barium ion cloud 'skids' about 15 km within the first three seconds following the release, consistent with the optical data analyses.

  20. Fatal barium chloride poisoning: four cases report and literature review.

    PubMed

    Ananda, Sunnassee; Shaohua, Zhu; Liang, Liu

    2013-06-01

    Barium is an alkaline earth metal which has a variety of uses including in the manufacturing industry and in medicine. However, adverse health effects and fatalities occur due to absorption of soluble barium compounds, notably the chloride, nitrate, and hydroxide, which are toxic to humans. Although rare, accidental and suicidal modes of poisoning are sporadically reported in the literature.We describe 4 cases of poisoning due to barium chloride in China. In witnessed cases, severe gastrointestinal symptoms, hypokalemia leading to muscle weakness, cardiac arrhythmias, and respiratory failure were noted. Autopsy showed some nonspecific but common findings, such as subendocardial hemorrhage in the ventricles, visceral petechiae, and fatty changes in the liver. Interestingly, microscopic examination showed degenerative changes and amorphous, flocculent foamy materials in the renal tubules. Toxicology was relevant for barium in blood and tissues. Three of the cases were accidental and 1 homicidal in nature. A round-up of relevant literature on fatal barium compounds poisoning is also provided. Forensic pathologists should be aware of the clinical presentations of barium compound poisoning and especially look for any evidence of hypokalemia. Still, postmortem toxicological and histological studies are essential for an accurate identification of the cause of death.

  1. Anastomotic stenosis of the descending colon caused by barium granuloma formation following barium peritonitis: report of a case.

    PubMed

    Kitajima, Toshihiro; Tomizawa, Kenji; Hanaoka, Yutaka; Toda, Shigeo; Matoba, Shuichiro; Kuroyanagi, Hiroya; Oota, Yasunori

    2014-11-01

    Anastomotic stricture reportedly often recurs following barium peritonitis, regardless of whether the anastomotic diameter is initially sufficient. However, the causes of repetitive stricture have not been clarified. We report a case that suggests the pathophysiology of recurrent anastomotic strictures following barium peritonitis. The patient was a 39-year-old Japanese man with idiopathic perforation of the descending colon after undergoing an upper gastrointestinal barium contrast study. After emergency peritoneal lavage and diverting colostomy, created using the perforated region, the patient recovered uneventfully and 3 months later, the colostomy was closed and the perforated colon was resected. However, 7 months after colostomy closure, abdominal distention gradually developed, and colonoscopy revealed an anastomotic stricture. The patient was referred to our hospital where he underwent resection of the anastomotic stricture. The surgical specimen exhibited barium granulomas not only in the subserosa of the entire specimen, but also in the submucosa and lamina propria localized in the anastomotic site. These findings suggest that barium was embedded in the submucosa and lamina propria with manipulation of the stapled anastomosis and that the barium trapped in the anastomotic site caused persistent inflammation, resulting in an anastomotic stricture.

  2. Barium determination in gastric contents, blood and urine by inductively coupled plasma mass spectrometry in the case of oral barium chloride poisoning.

    PubMed

    Łukasik-Głębocka, Magdalena; Sommerfeld, Karina; Hanć, Anetta; Grzegorowski, Adam; Barałkiewicz, Danuta; Gaca, Michał; Zielińska-Psuja, Barbara

    2014-01-01

    A serious case of barium intoxication from suicidal ingestion is reported. Oral barium chloride poisoning with hypokalemia, neuromuscular and cardiac toxicity, treated with intravenous potassium supplementation and hemodialysis, was confirmed by the determination of barium concentrations in gastric contents, blood, serum and urine using the inductively coupled plasma mass spectrometry method. Barium concentrations in the analyzed specimens were 20.45 µg/L in serum, 150 µg/L in blood, 10,500 µg/L in urine and 63,500 µg/L in gastric contents. Results were compared with barium levels obtained from a non-intoxicated person.

  3. High pressure FAST of nanocrystalline barium titanate

    SciTech Connect

    Fraga, Martin B.; Delplanque, Jean -Pierre; Yang, Nancy; Lavernia, Enrique J.; Monson, Todd C.

    2016-06-01

    Here, this work studies the microstructural evolution of nanocrystalline (<1 µm) barium titanate (BaTiO3), and presents high pressure in field-assisted sintering (FAST) as a robust methodology to obtain >100 nm BaTiO3 compacts. Using FAST, two commercial ~50 nm powders were consolidated into compacts of varying densities and grain sizes. Microstructural inhomogeneities were investigated for each case, and an interpretation is developed using a modified Monte Carlo Potts (MCP) simulation. Two recurrent microstructural inhomogeneities are highlighted, heterogeneous grain growth and low-density regions, both ubiqutously present in all samples to varying degrees. In the worst cases, HGG presents an area coverage of 52%. Because HGG is sporadic but homogenous throughout a sample, the catalyst (e.g., the local segregation of species) must be, correspondingly, distributed in a homogenous manner. MCP demonstrates that in such a case, a large distance between nucleating abnormal grains is required—otherwise abnormal grains prematurely impinge on each other, and their size is not distinguishable from that of normal grains. Compacts sintered with a pressure of 300 MPa and temperatures of 900 °C, were 99.5% dense and had a grain size of 90±24 nm. These are unprecedented results for commercial BaTiO3 powders or any starting powder of 50 nm particle size—other authors have used 16 nm lab-produced powder to obtain similar results.

  4. High pressure FAST of nanocrystalline barium titanate

    DOE PAGES

    Fraga, Martin B.; Delplanque, Jean -Pierre; Yang, Nancy; ...

    2016-06-01

    Here, this work studies the microstructural evolution of nanocrystalline (<1 µm) barium titanate (BaTiO3), and presents high pressure in field-assisted sintering (FAST) as a robust methodology to obtain >100 nm BaTiO3 compacts. Using FAST, two commercial ~50 nm powders were consolidated into compacts of varying densities and grain sizes. Microstructural inhomogeneities were investigated for each case, and an interpretation is developed using a modified Monte Carlo Potts (MCP) simulation. Two recurrent microstructural inhomogeneities are highlighted, heterogeneous grain growth and low-density regions, both ubiqutously present in all samples to varying degrees. In the worst cases, HGG presents an area coverage ofmore » 52%. Because HGG is sporadic but homogenous throughout a sample, the catalyst (e.g., the local segregation of species) must be, correspondingly, distributed in a homogenous manner. MCP demonstrates that in such a case, a large distance between nucleating abnormal grains is required—otherwise abnormal grains prematurely impinge on each other, and their size is not distinguishable from that of normal grains. Compacts sintered with a pressure of 300 MPa and temperatures of 900 °C, were 99.5% dense and had a grain size of 90±24 nm. These are unprecedented results for commercial BaTiO3 powders or any starting powder of 50 nm particle size—other authors have used 16 nm lab-produced powder to obtain similar results.« less

  5. High H- ionic conductivity in barium hydride

    NASA Astrophysics Data System (ADS)

    Verbraeken, Maarten C.; Cheung, Chaksum; Suard, Emmanuelle; Irvine, John T. S.

    2015-01-01

    With hydrogen being seen as a key renewable energy vector, the search for materials exhibiting fast hydrogen transport becomes ever more important. Not only do hydrogen storage materials require high mobility of hydrogen in the solid state, but the efficiency of electrochemical devices is also largely determined by fast ionic transport. Although the heavy alkaline-earth hydrides are of limited interest for their hydrogen storage potential, owing to low gravimetric densities, their ionic nature may prove useful in new electrochemical applications, especially as an ionically conducting electrolyte material. Here we show that barium hydride shows fast pure ionic transport of hydride ions (H-) in the high-temperature, high-symmetry phase. Although some conductivity studies have been reported on related materials previously, the nature of the charge carriers has not been determined. BaH2 gives rise to hydride ion conductivity of 0.2 S cm-1 at 630 °C. This is an order of magnitude larger than that of state-of-the-art proton-conducting perovskites or oxide ion conductors at this temperature. These results suggest that the alkaline-earth hydrides form an important new family of materials, with potential use in a number of applications, such as separation membranes, electrochemical reactors and so on.

  6. Prospects for Barium Tagging in Gaseous Xenon

    SciTech Connect

    Sinclair, D.; Rollin, E.; Smith, J.; Mommers, A.; Ackerman, N.; Aharmim, B.; Auger, M.; Barbeau, P.S.; Benitez-Medina, C.; Breidenbach, M.; Burenkov, A.; Cook, S.; Coppens, A.; Daniels, T.; DeVoe, R.; Dobi, A.; Dolinski, M.J.; Donato, K.; Fairbank, W., Jr.; Farine, J.; Giroux, G.; /Bern U., LHEP /Carleton U. /Stanford U., Phys. Dept. /Carleton U. /Laurentian U. /Carleton U. /SLAC /Indiana U. /Indiana U., CEEM /Korea U. /Stanford U., Phys. Dept. /SLAC /Alabama U. /Colorado State U. /Stanford U., Phys. Dept. /Alabama U. /SLAC /Stanford U., Phys. Dept. /Alabama U. /Massachusetts U., Amherst /SLAC /Alabama U. /SLAC /Maryland U. /Moscow, ITEP /Stanford U., Phys. Dept. /Maryland U. /Bern U., LHEP /Laurentian U. /SLAC /Maryland U.

    2012-05-03

    Tagging events with the coincident detection of a barium ion would greatly reduce the background for a neutrino-less double beta decay search in xenon. This paper describes progress towards realizing this goal. It outlines a source that can produce large quantities of Ba++ in gas, shows that this can be extracted to vacuum, and demonstrates a mechanism by which the Ba++ can be efficiently converted to Ba+ as required for laser identification. It is clear from this study that electrospray is a convenient mechanism for producing Ba++ is gas at atmospheric pressure. It is likely that the source will perform just as effectively at higher pressures. Even though the source region has water vapour and methanol vapour at the 0.3% level, there is no evidence for molecular formation. The use of TEA offers an effective method to achieve the charge state conversion. The overall design of the ion extraction from high pressure to vacuum is very similar to the scheme proposed for the final detector and this appears to work well although the efficiency is not yet determined.

  7. High pressure FAST of nanocrystalline barium titanate

    SciTech Connect

    Fraga, Martin B.; Delplanque, Jean -Pierre; Yang, Nancy; Lavernia, Enrique J.; Monson, Todd C.

    2016-06-01

    Here, this work studies the microstructural evolution of nanocrystalline (<1 µm) barium titanate (BaTiO3), and presents high pressure in field-assisted sintering (FAST) as a robust methodology to obtain >100 nm BaTiO3 compacts. Using FAST, two commercial ~50 nm powders were consolidated into compacts of varying densities and grain sizes. Microstructural inhomogeneities were investigated for each case, and an interpretation is developed using a modified Monte Carlo Potts (MCP) simulation. Two recurrent microstructural inhomogeneities are highlighted, heterogeneous grain growth and low-density regions, both ubiqutously present in all samples to varying degrees. In the worst cases, HGG presents an area coverage of 52%. Because HGG is sporadic but homogenous throughout a sample, the catalyst (e.g., the local segregation of species) must be, correspondingly, distributed in a homogenous manner. MCP demonstrates that in such a case, a large distance between nucleating abnormal grains is required—otherwise abnormal grains prematurely impinge on each other, and their size is not distinguishable from that of normal grains. Compacts sintered with a pressure of 300 MPa and temperatures of 900 °C, were 99.5% dense and had a grain size of 90±24 nm. These are unprecedented results for commercial BaTiO3 powders or any starting powder of 50 nm particle size—other authors have used 16 nm lab-produced powder to obtain similar results.

  8. Barium Tagging for nEXO

    NASA Astrophysics Data System (ADS)

    Fudenberg, Daniel; Brunner, Thomas; Varentsov, Victor; Devoe, Ralph; Dilling, Jens; Gratta, Giorgio; nEXO Collaboration

    2015-10-01

    nEXO is a next-generation experiment designed to search for 0 νββ -decay of Xe-136 in a liquid xenon time projection chamber. Positive observation of this decay would determine the neutrino to be a Majorana particle In order to greatly reduce background contributions to this search, the collaboration is developing several ``barium tagging'' techniques to recover and identify the decay daughter, Ba-136. ``Tagging'' may be available for a 2nd phase of nEXO and will push the sensitivity beyond the inverted neutrino-mass hierarchy. Tagging methods in testing for this phase include Ba-ion capture on a probe with identification by resonance ionization laser spectroscopy, and Ba capture in solid xenon on a cold probe with identification by fluorescence. In addition, Ba tagging for a gas-phase detector, appropriate for a later stage, is being tested. Here efficient ion extraction from heavy carrier gases is key. Detailed gas-dynamic and ion transport calculations have been performed to optimize for ion extraction. An apparatus to extract Ba ions from up to 10 bar xenon gas into vacuum using an RF-only funnel has been constructed and demonstrates extraction of ions from noble gases. We will present this system's status along with results of this R&D program.

  9. Acceleration of barium ions near 8000 km above an aurora

    NASA Technical Reports Server (NTRS)

    Stenbaek-Nielsen, H. C.; Hallinan, T. J.; Wescott, E. M.; Foeppl, H.

    1984-01-01

    A barium shaped charge, named Limerick, was released from a rocket launched from Poker Flat Research Range, Alaska, on March 30, 1982, at 1033 UT. The release took place in a small auroral breakup. The jet of ionized barium reached an altitude of 8100 km 14.5 min after release, indicating that there were no parallel electric fields below this altitude. At 8100 km the jet appeared to stop. Analysis shows that the barium at this altitude was effectively removed from the tip. It is concluded that the barium was actually accelerated upward, resulting in a large decrease in the line-of-sight density and hence the optical intensity. The parallel electric potential in the acceleration region must have been greater than 1 kV over an altitude interval of less than 200 km. The acceleration region, although presumably auroral in origin, did not seem to be related to individual auroral structures, but appeared to be a large-scale horizontal structure. The perpendicular electric field below, as deduced from the drift of the barium, was temporally and spatially very uniform and showed no variation related to individual auroral structures passing through.

  10. Preparation of barium hexaferrite powders using oxidized steel scales waste

    NASA Astrophysics Data System (ADS)

    Septiani, Ardita; Idayanti, Novrita; Kristiantoro, Tony

    2016-02-01

    Research on preparation of barium hexaferrite powders has been done using Hot Strip Mill scales as raw materials. Hot Strip Mill scales are oxidized steel scales waste from steel industrial process. The method used for preparing the barium hexaferrite powders was solid state reaction method. Oxidized steel scales were milled using ball mill for 10 hours, then screened through a 250 mesh sieve to obtain powders with maximum size of 63 µm. Powders were roasted at 600°C temperature for 4 hours to obtain hematite (Fe2O3) phase. Roasted powders were then mixed with barium carbonate, and were subsequently milled for 16 hours. After mixing, powders were calcined with an increasing rate of 10°C/min and maintained at 1100°C for 3 hours. Calcination process was performed to acquire barium hexaferrite phase. X-ray Diffraction (XRD) characterization in conjunction with RIR analysis showed that 85 wt. % of barium hexaferrite is formed. The magnetic properties of powders were characterized using Permagraph. It is found the value of remanent induction is 1.09 kG, coercivity of 2.043 kOe, and the maximum energy product of 0.25 MGOe.

  11. Barium Depletion in the NSTAR Discharge Cathode After 30,000 Hours of Operation

    NASA Technical Reports Server (NTRS)

    Polk, James E.; Capece, Angela M.; Mikellides, Ioannis G.; Katz, Ira

    2010-01-01

    Dispenser hollow cathodes rely on a consumable supply of barium released by impregnant materials in the pores of a tungsten matrix to maintain a low work function surface. Examinations of cathode inserts from long duration ion engine tests show deposits of tungsten at the downstream end that appear to block the flow of barium from the interior. In addition, a numerical model of barium transport in the insert plasma indicates that the barium partial pressure in the insert may exceed the equilibrium vapor pressure of the dominant barium-producing reaction, and it was postulated previously that this would suppress barium loss in the upstream part of the insert. New measurements of the depth of barium depletion from a cathode insert operated for 30,352 hours reveal that barium loss is confined to a narrow region near the downstream end, confirming this hypothesis.

  12. Barium Depletion in the NSTAR Discharge Cathode After 30,000 Hours of Operation

    NASA Technical Reports Server (NTRS)

    Polk, James E.; Capece, Angela M.; Mikellides, Ioannis G.; Katz, Ira

    2010-01-01

    Dispenser hollow cathodes rely on a consumable supply of barium released by impregnant materials in the pores of a tungsten matrix to maintain a low work function surface. Examinations of cathode inserts from long duration ion engine tests show deposits of tungsten at the downstream end that appear to block the flow of barium from the interior. In addition, a numerical model of barium transport in the insert plasma indicates that the barium partial pressure in the insert may exceed the equilibrium vapor pressure of the dominant barium-producing reaction, and it was postulated previously that this would suppress barium loss in the upstream part of the insert. New measurements of the depth of barium depletion from a cathode insert operated for 30,352 hours reveal that barium loss is confined to a narrow region near the downstream end, confirming this hypothesis.

  13. Rocket having barium release system to create ion clouds in the upper atmosphere

    NASA Technical Reports Server (NTRS)

    Lewis, B. W.; Stokes, C. S.; Smith, E. W.; Murphy, W. J. (Inventor)

    1974-01-01

    A chemical system for releasing a good yield of free barium atoms and barium ions to create ion clouds in the upper atmosphere and interplanetary space for the study of the geophysical properties of the medium is presented.

  14. Regulation of serum phosphate

    PubMed Central

    Lederer, Eleanor

    2014-01-01

    The regulation of serum phosphate, an acknowledged risk factor for chronic kidney disease and cardiovascular mortality, is poorly understood. The discovery of fibroblast growth factor 23 (FGF23) as a key regulator of renal phosphate handling and activation of vitamin D has revolutionized our comprehension of phosphate homeostasis. Through as yet undetermined mechanisms, circulating and dietary phosphate appear to have a direct effect on FGF23 release by bone cells that, in turn, causes renal phosphate excretion and decreases intestinal phosphate absorption through a decrease in vitamin D production. Thus, the two major phosphaturic hormones, PTH and FGF23, have opposing effects on vitamin D production, placing vitamin D at the nexus of phosphate homeostasis. While our understanding of phosphate homeostasis has advanced, the factors determining regulation of serum phosphate level remain enigmatic. Diet, time of day, season, gender, age and genetics have all been identified as significant contributors to serum phosphate level. The effects of these factors on serum phosphate have major implications for what is understood as ‘normal’ and for studies of phosphate homeostasis and metabolism. Moreover, other hormonal mediators such as dopamine, insulin-like growth factor, and angiotensin II also affect renal handling of phosphate. How the major hormone effects on phosphate handling are regulated and how the effect of these other factors are integrated to yield the measurable serum phosphate are only now beginning to be studied. PMID:24973411

  15. Platinum in phosphate laser glasses

    NASA Astrophysics Data System (ADS)

    Click, Carol Ann

    The platinum concentration in phosphate laser glasses has been characterized as a function of composition, melting time and temperature. The highest measured ionic platinum concentration is 2042 ppmw in a potassium-alumino-metaphosphate glass after 24 hours of melting at 900°C. The maximum platinum concentration in a given composition decreases with increasing temperature. The time, temperature and composition dependent platinum concentration in the melt depends on the relative rates of the platinum dissolution from the crucible wall into and platinum oxide volatilization out of the glass melt. As such, the platinum concentration in the melt can be seen to decrease with increasing time under some conditions. The local environment of the ionic platinum in these glasses has been investigated using optical spectroscopy. The ionic platinum is incorporated as Pt4+ ions in a distorted octahedral symmetry. This platinum is characterized by optical absorption occurring at wavelengths less than 500nm (energy > 20,000 cm-1) due to d-d electronic transitions. The addition of chlorine to the system results in an electronic transition shift to greater wavelengths in barium free glasses, which indicates that the chlorine is coordinating to the platinum in the barium free glasses. The effect of platinum on the Nd3+ 4F 3/2 → 4I11/2 fluorescence decay rate in a commercial laser glass has been investigated, and the effect is negligible. However, the effects of hydroxyl concentration and Nd2O3 concentration on the fluorescence decay rate are substantial and have been investigated in potassium-magnesium-aluminometaphosphate glasses with Nd 2O3 contents ranging from 0.5 to 8.0 weight%. The hydroxyl concentration ranged from ˜3 to 43 cm-1 at 3.33 mum, corresponding to hydroxyl concentrations of ˜300 to 4300 ppm. The fluorescence quenching rate of the Nd3+ ions by hydroxyls increases linearly with Nd atomic concentration, and when extrapolated to zero Nd concentration, has a value

  16. Barium Levels in Soils and Centella asiatica

    PubMed Central

    Ong, Ghim Hock; Yap, Chee Kong; Mahmood, Maziah; Tan, Soon Guan; Hamzah, Suhaimi

    2013-01-01

    In this study, Centella asiatica and surface soils were collected from 12 sampling sites in Peninsular Malaysia, and the barium (Ba) concentrations were determined. The Ba concentration [μg/g dry weight (dw)] was 63.72 to 382.01 μg/g in soils while in C. asiatica, Ba concentrations ranged from 5.05 to 21.88 μg/g for roots, 3.31 to 11.22 μg/g for leaves and 2.37 to 6.14 μg/g for stems. In C. asiatica, Ba accumulation was found to be the highest in roots followed by leaves and stems. The correlation coefficients (r) of Ba between plants and soils were found to be significantly positively correlated, with the highest correlation being between roots-soils (r=0.922, p<005), followed by leaves-soils (r=0.890, p<005) and stems-soils (r=0.848, p<005). This indicates that these three parts of C. asiatica are good biomonitors of Ba pollution. For the transplantation study, four sites were selected as unpolluted [(Universiti Putra Malaysia (UPM)], semi-polluted (Seri Kembangan and Balakong) and polluted sites (Juru). Based on the transplantation study under experimental field and laboratory conditions, Ba concentrations in C. asiatica were significantly (p<0.05) higher after three weeks of exposure at Seri Kembangan, Balakong and Juru. Thus, these experimental findings confirm that the leaves, stems and roots of C. asiatica can reflect the Ba levels in the soils where this plant is found. Three weeks after back transplantation to clean soils, the Ba levels in C. asiatica were still higher than the initial Ba level even though Ba elimination occurred. In conclusion, the leaves, stems and roots of C. asiatica are good biomonitors of Ba pollution. PMID:24575242

  17. Barium Levels in Soils and Centella asiatica.

    PubMed

    Ong, Ghim Hock; Yap, Chee Kong; Mahmood, Maziah; Tan, Soon Guan; Hamzah, Suhaimi

    2013-08-01

    In this study, Centella asiatica and surface soils were collected from 12 sampling sites in Peninsular Malaysia, and the barium (Ba) concentrations were determined. The Ba concentration [μg/g dry weight (dw)] was 63.72 to 382.01 μg/g in soils while in C. asiatica, Ba concentrations ranged from 5.05 to 21.88 μg/g for roots, 3.31 to 11.22 μg/g for leaves and 2.37 to 6.14 μg/g for stems. In C. asiatica, Ba accumulation was found to be the highest in roots followed by leaves and stems. The correlation coefficients (r) of Ba between plants and soils were found to be significantly positively correlated, with the highest correlation being between roots-soils (r=0.922, p<005), followed by leaves-soils (r=0.890, p<005) and stems-soils (r=0.848, p<005). This indicates that these three parts of C. asiatica are good biomonitors of Ba pollution. For the transplantation study, four sites were selected as unpolluted [(Universiti Putra Malaysia (UPM)], semi-polluted (Seri Kembangan and Balakong) and polluted sites (Juru). Based on the transplantation study under experimental field and laboratory conditions, Ba concentrations in C. asiatica were significantly (p<0.05) higher after three weeks of exposure at Seri Kembangan, Balakong and Juru. Thus, these experimental findings confirm that the leaves, stems and roots of C. asiatica can reflect the Ba levels in the soils where this plant is found. Three weeks after back transplantation to clean soils, the Ba levels in C. asiatica were still higher than the initial Ba level even though Ba elimination occurred. In conclusion, the leaves, stems and roots of C. asiatica are good biomonitors of Ba pollution.

  18. Selectivity in biomineralization of barium and strontium.

    PubMed

    Krejci, Minna R; Wasserman, Brian; Finney, Lydia; McNulty, Ian; Legnini, Daniel; Vogt, Stefan; Joester, Derk

    2011-11-01

    The desmid green alga Closterium moniliferum belongs to a small number of organisms that form barite (BaSO(4)) or celestite (SrSO(4)) biominerals. The ability to sequester Sr in the presence of an excess of Ca is of considerable interest for the remediation of (90)Sr from the environment and nuclear waste. While most cells dynamically regulate the concentration of the second messenger Ca(2+) in the cytosol and various organelles, transport proteins rarely discriminate strongly between Ca, Sr, and Ba. Herein, we investigate how these ions are trafficked in C. moniliferum and how precipitation of (Ba,Sr)SO(4) crystals occurs in the terminal vacuoles. Towards this goal, we simultaneously visualize intracellular dynamics of multiple elements using X-ray fluorescence microscopy (XFM) of cryo-fixed/freeze-dried samples. We correlate the resulting elemental maps with ultrastructural information gleaned from freeze-fracture cryo-SEM of frozen-hydrated cells and use micro X-ray absorption near edge structure (micro-XANES) to determine sulfur speciation. We find that the kinetics of Sr uptake and efflux depend on external Ca concentrations, and Sr, Ba, and Ca show similar intracellular localization. A highly ion-selective cross-membrane transport step is not evident. Based on elevated levels of sulfate detected in the terminal vacuoles, we propose a "sulfate trap" model, where the presence of dissolved barium leads to preferential precipitation of (Ba,Sr)SO(4) due to its low solubility relative to SrSO(4) and CaSO(4). Engineering the sulfate concentration in the vacuole may thus be the most direct way to increase the Sr sequestered per cell, an important consideration in using desmids for phytoremediation of (90)Sr.

  19. Barium recovery by crystallization in a fluidized-bed reactor: effects of pH, Ba/P molar ratio and seed.

    PubMed

    Su, Chia-Chi; Reano, Resmond L; Dalida, Maria Lourdes P; Lu, Ming-Chun

    2014-06-01

    The effects of process conditions, including upward velocity inside the column, the amount of added seed and seed size, the pH value of the precipitant or the phosphate stream and the Ba/P molar ratio in a fluidized-bed reactor (FBR) were studied with a view to producing BaHPO₄ crystals of significant size and maximize the removal of barium. XRD were used to identify the products that were collected from the FBR. Experimental results show that an upward velocity of 48 cmmin(-1) produced the largest BaHPO₄ crystals with a size of around 0.84-1.0mm. The addition of seed crystals has no effect on barium removal. The use of a seed of a size in the ranges unseeded<0.149-0.29 mm<0.149 mm<0.29-0.42 mm produced increasing amounts of increasingly large crystals. The largest BaHPO₄ crystals were obtained at pH 8.4-8.8 with a Ba/P molar ratio of 1.0. In the homogeneous and heterogeneous processes, around 98% of barium was removed at pH 8.4-8.6 and [Ba]/[P]=1.0. The XRD results show that a significant amount of barium phosphate (Ba₃(PO₄)₂) was obtained at pH 11. The compounds BaHPO₄ and BaO were present at a pH of below 10. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Emission spectrographic determination of barium in sea water using a cation exchange concentration procedure

    USGS Publications Warehouse

    Szabo, B. J.; Joensuu, O.

    1967-01-01

    A concentration technique employing Dowex 50W cation exchange resin is described for the determination of barium in sea water. The separated barium is precipitated as fluoride together with calcium and strontium and measured by emission spectrographic analysis. The vertical distribution of barium in sea water has been measured in the Caribbean Sea and the Atlantic Ocean. The barium content varied between 7 and 23 ??g. per liter; in two profiles, the lowest concentrations were at a depth of about 1000 meters.

  1. Barium-borate-flyash glasses: As radiation shielding materials

    NASA Astrophysics Data System (ADS)

    Singh, Sukhpal; Kumar, Ashok; Singh, Devinder; Thind, Kulwant Singh; Mudahar, Gurmel S.

    2008-01-01

    The attenuation coefficients of barium-borate-flyash glasses have been measured for γ-ray photon energies of 356, 662, 1173 and 1332 keV using narrow beam transmission geometry. The photon beam was highly collimated and overall scatter acceptance angle was less than 3°. Our results have an uncertainty of less than 3%. These coefficients were then used to obtain the values of mean free path (mfp), effective atomic number and electron density. Good agreements have been observed between experimental and theoretical values of these parameters. From the studies of the obtained results it is reported here that from the shielding point of view the barium-borate-flyash glasses are better shields to γ-radiations in comparison to the standard radiation shielding concretes and also to the ordinary barium-borate glasses.

  2. White dwarf kicks and implications for barium stars

    NASA Astrophysics Data System (ADS)

    Izzard, R. G.; Church, R. P.; Dermine, T.

    The barium stars have caused much grief in the field of binary stellar evolution. They are often eccentric when they should be circular and are not found to have periods longer than 104 days even though wind accretion should still be efficient at such separations. We address both these problems by introducing a kick to white dwarfs when they are born, thus solving the eccentricity problem, and imposing strong orbital angular momentum loss to shrink barium-star binaries down to the observed periods. Whilst our angular momentum prescription is hard to justify for the barium stars it shows that strong angular momentum loss is necessary to reproduce the observed period-eccentricity distribution. We are investigating whether this can be obtained from a circumbinary disc.

  3. Prompt ionization in the CRIT II barium releases

    NASA Astrophysics Data System (ADS)

    Torbert, R. B.; Kletzing, C. A.; Liou, K.; Rau, D.

    1992-05-01

    Observations of electron and ion distributions inside a fast neutral barium jet in the ionosphere show significant fluxes within 4 km of release, presumably related to beam plasma instability processes involved in the Critical Ionization Velocity (CIV) effect. Electron fluxes exceeding 5 x 10 exp 12/sq cm-str-sec-keV were responsible for ionizing both the streaming barium and ambient oxygen. Resulting ion fluxes seem to be consistent with 1-2 percent ionization of the fast barium, as reported by optical observations, although the extended spatial distribution of the optically observed ions is difficult to reconcile with the in situ observations. When the perpendicular velocity of the neutrals falls below critical values, these processes shut off. Although these observations resemble the earlier Porcupine experimental results (Haerendel, 1982), theoretical understanding of the differences between these data and that of earlier negative experiments is still lacking.

  4. Multiphoton laser ionization for energy conversion in barium vapor

    NASA Astrophysics Data System (ADS)

    Makdisi, Y.; Kokaj, J.; Afrousheh, K.; Mathew, J.; Nair, R.; Pichler, G.

    2013-03-01

    We have studied the ion detection of barium atoms in special heated ovens with a tungsten rod in the middle of the stainless steel tube. The tungsten rod was heated indirectly by the oven body heaters. A bias voltage between the cell body and the tungsten rod of 9 V was used to collect electrons, after the barium ions had been created. However, we could collect the electrons even without the bias voltage, although with ten times less efficiency. We studied the conditions for the successful bias-less thermionic signal detection using excimer/dye laser two-photon excitation of Rydberg states below and above the first ionization limit (two-photon wavelength at 475.79 nm). We employed a hot-pipe oven and heat-pipe oven (with inserted mesh) in order to generate different barium vapor distributions inside the oven. The thermionic signal increased by a factor of two under heat-pipe oven conditions.

  5. Electro-optical polycrystalline barium lanthanum titanium niobate

    SciTech Connect

    Mehrotra, A.K.

    1991-02-19

    This patent describes a transparent electro-optic article. It comprises: of a barium lanthanum titanium niobate wherein substantially all grains are of a grain size between about 2 and about 20 micron, the article has a pore volume of less than about 1 percent, and the article has a grain size of between about 2 and about 20 microns. This patent also describes a method of forming transparent electro-optical barium lanthanum titanium niobate. It comprises: providing particles of barium carbonate, lanthanum oxide, titanium oxide, and niobium oxide, calcining the particles, sintering the calcined particles at a temperature of between about 1200{degrees} C and 1300{degrees} C. and a vacuum of between about 10{sup {minus}3} and 10{sup {minus}4} torr while under pressure to form a sintered mass, cooling the sintered mass, slicing the mass to form wafers, heating the wafers in an oxidizing atmosphere.

  6. Acute barium toxicity from ingestion of "snake" fireworks.

    PubMed

    Rhyee, Sean H; Heard, Kennon

    2009-12-01

    Ingestion of fireworks has been infrequently reported in the medical literature. We describe a case of acute barium poisoning following firework ingestion. A 35-year-old male with a history of severe mental retardation presented with vomiting and diarrhea following ingestion of 16 small fireworks ("color snakes" and "black snakes"). His condition rapidly deteriorated and he developed obtundation, wide complex dysrhythmias, and respiratory failure. Approximately 12 hours following ingestion, his serum potassium level was 1.5 mmol/L with a serum barium level of 20,200 microg/mL (reference range <200 microg/L). The patient eventually recovered with ventilatory support and potassium supplementation. Although firework ingestion is uncommon, clinicians should be prepared for potentially severe complications. In the case of barium poisoning, treatment consists of potassium supplementation, along with respiratory and hemodynamic support.

  7. Compact pulse forming line using barium titanate ceramic material

    NASA Astrophysics Data System (ADS)

    Kumar Sharma, Surender; Deb, P.; Shukla, R.; Prabaharan, T.; Shyam, A.

    2011-11-01

    Ceramic material has very high relative permittivity, so compact pulse forming line can be made using these materials. Barium titanate (BaTiO3) has a relative permittivity of 1200 so it is used for making compact pulse forming line (PFL). Barium titanate also has piezoelectric effects so it cracks during high voltages discharges due to stresses developed in it. Barium titanate is mixed with rubber which absorbs the piezoelectric stresses when the PFL is charged and regain its original shape after the discharge. A composite mixture of barium titanate with the neoprene rubber is prepared. The relative permittivity of the composite mixture is measured to be 85. A coaxial pulse forming line of inner diameter 120 mm, outer diameter 240 mm, and length 350 mm is made and the composite mixture of barium titanate and neoprene rubber is filled between the inner and outer cylinders. The PFL is charged up to 120 kV and discharged into 5 Ω load. The voltage pulse of 70 kV, 21 ns is measured across the load. The conventional PFL is made up of oil or plastics dielectrics with the relative permittivity of 2-10 [D. R. Linde, CRC Handbook of Chemistry and Physics, 90th ed. (CRC, 2009); Xia et al., Rev. Sci. Instrum. 79, 086113 (2008); Yang et al., Rev. Sci. Instrum. 81, 43303 (2010)], which increases the length of PFL. We have reported the compactness in length achieved due to increase in relative permittivity of composite mixture by adding barium titanate in neoprene rubber.

  8. Diagnosis of anastomotic leak: electrolyte detection versus barium fluoroscopy.

    PubMed

    DeArmond, Daniel T; Carswell, Aimee; Louden, Christopher L; Simmons, Jeremy D; Bayer, Johanna; Das, Nitin A; Johnson, Scott B

    2013-06-15

    We recently described a new method of diagnosing anastomotic leak using the detection of electrical changes induced by electrolyte extravasation from a surgically created gastric leak site in experimental rats. We sought to compare the sensitivity and specificity of anastomotic leak detection for this method to that of upper gastrointestinal (GI) barium fluoroscopy. Experimental rats with a surgically created gastric leak site and controls were interrogated as to the presence of leak using either the electrolyte-gated leak detection method or upper GI barium fluoroscopy. The sensitivity and specificity of leak detection for the two methods were compared. The sensitivity and specificity of electrolyte-gated leak detection were both 100% (95% confidence interval 69-100%). Barium upper GI fluoroscopy misidentified one leak as a control and one control as a leak, for a sensitivity and specificity of 80% each (95% confidence interval 37-97%). No statistically significant difference was seen between electrolyte-gated leak detection and barium upper GI fluoroscopy in terms of the sensitivity and specificity of anastomotic leak detection. Electrolyte-gated leak detection was similarly sensitive and specific for anastomotic leak detection as upper GI barium fluoroscopy, the current standard. The electrolyte-gated method has the advantages of an inert contrast agent (normal saline) and the possibility of performing leak interrogation at the bedside. Electrolyte-gated leak detection might represent a plausible alternative to upper GI barium fluoroscopy for routine postoperative anastomotic leak surveillance after esophagectomy or other foregut surgery. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. 40 CFR 721.10010 - Barium manganese oxide (BaMnO3).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Barium manganese oxide (BaMnO3). 721... Substances § 721.10010 Barium manganese oxide (BaMnO3). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as barium manganese oxide (BaMnO3) (PMN P-00...

  10. 40 CFR 721.10010 - Barium manganese oxide (BaMnO3).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Barium manganese oxide (BaMnO3). 721... Substances § 721.10010 Barium manganese oxide (BaMnO3). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as barium manganese oxide (BaMnO3) (PMN P-00...

  11. 40 CFR 721.10010 - Barium manganese oxide (BaMnO3).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Barium manganese oxide (BaMnO3). 721... Substances § 721.10010 Barium manganese oxide (BaMnO3). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as barium manganese oxide (BaMnO3) (PMN P-00...

  12. 40 CFR 721.10010 - Barium manganese oxide (BaMnO3).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Barium manganese oxide (BaMnO3). 721... Substances § 721.10010 Barium manganese oxide (BaMnO3). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as barium manganese oxide (BaMnO3) (PMN P-00...

  13. 40 CFR 721.10010 - Barium manganese oxide (BaMnO3).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Barium manganese oxide (BaMnO3). 721... Substances § 721.10010 Barium manganese oxide (BaMnO3). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as barium manganese oxide (BaMnO3) (PMN...

  14. Phenotypic and behavioral defects caused by barium exposure in nematode Caenorhabditis elegans.

    PubMed

    Wang, D-Y; Wang, Y

    2008-04-01

    To examine the possible phenotypic defects from barium exposure, a model organism, Caenorhabditis elegans, was chosen to analyze the multiple toxicities in barium-exposed animals. Endpoints of life span, body size, brood size, generation time, head thrash, and body bend were selected for the assessment of barium toxicity. High concentrations (75 microM and 200 microM) of barium exposure caused severe life-span defects. Body sizes of exposed animals were markedly reduced compared to the controls, and high concentrations of barium exposure (75 microM and 200 microM) caused the appearance of vulva abnormality. In addition, barium exposure resulted in severe defects in reproductive capacity and reproductive speed. Body bends and head thrashes were also severely impaired after barium exposure. Furthermore, the stress responses to barium exposure suggest severe barium toxicity. The observed severe locomotion behavior and life-span defects in nematodes might be largely due to the deposition of barium toxicity in the muscle and intestine systems, respectively. Our data suggest that barium exposure could cause multiple biological defects by affecting the life span, development, reproduction, and locomotion behaviors. These multiple biological defects provide a new evaluation system to monitor the toxicity from barium exposure.

  15. Volatile Barium Beta-Diketonate Polyether Adducts. Synthesis, Characterization and Metalorganic Chemical Vapor Deposition

    DTIC Science & Technology

    1991-05-31

    Volatile Barium 13- Diketonate Polyether Adducts.... Synthesis , Characterization and Metalorganic Chemical Vapor Deposition by Robin A. Gardiner...has been approved for public release and sale: its distribution is unlimited. Volatile, Barium B- Diketonate Polyether Adducts. Synthesis ...NO. NO. INO. ACCESSION NO. Arlington, VA 22217 II 11. TITLE (include Security Classification) Volatile Barium B- Diketonate Polyether Adducts

  16. Phosphate Uptake by Phosphate-Starved Euglena

    PubMed Central

    BLUM, J. J.

    1966-01-01

    Phosphate-deprived Euglena acquire the ability to rapidly in-corporate added phosphate and, also, synthesize an induced acid phosphatase localized in the pellicle. The phosphate uptake system is saturated at low concentrations of phosphate and is inhibited by dinitrophenol, by low temperature, by K+, Li+, and Na+ ions, and competitively by arsenate. The orthophosphate incorporated into the cell is rapidly converted into organic forms but enough remains unesterified to suggest that the uptake is an active transport process. The data do not rule out the possibility that the induced phosphatase is involved in the transport process. PMID:5924104

  17. Deflocculants for Tape Casting Barium Titanate Dielectrics.

    DTIC Science & Technology

    1985-07-01

    Angela Karas, Richard Hill and Robert MacNiven. 4 ~~~~~~~. . .-..-....-...-.-.-,..-.. .. .... .... ,,.....,. •. ......... °,.,• : . 1 II. RiDerimental...consideration of work done by Wiersema, Loeb, and Overbeek (9) and Obrien and White (10). Electrophoretic velocities were measured as a function of phosphate...Henry, D.C., Proc. Ray. Soc., 1 (1931) 106. 9. Wiersema, P.H. Loeb, A.L., and Overbeek , J. Th., J. Colloid Interface Sci., 22 (1966) 78-99. 10. O’brien

  18. Study of the photovoltaic effect in thin film barium titanate

    NASA Technical Reports Server (NTRS)

    Grannemann, W. W.; Dharmadhikari, V. S.

    1981-01-01

    The photoelectric effect in structures consisting of metal deposited barium titanate film silicon is described. A radio frequency sputtering technique is used to deposit ferroelectric barium titantate films on silicon and quartz. Film properties are measured and correlated with the photoelectric effect characteristics of the films. It was found that to obtain good quality pin hole free films, it is necessary to reduce the substrate temperature during the last part of the deposition. The switching ability of the device with internal applied voltage is improved when applied with a ferroelectric memory device.

  19. Methods for producing monodispersed particles of barium titanate

    DOEpatents

    Hu, Zhong-Cheng

    2001-01-01

    The present invention is a low-temperature controlled method for producing high-quality, ultrafine monodispersed nanocrystalline microsphere powders of barium titanate and other pure or composite oxide materials having particles ranging from nanosized to micronsized particles. The method of the subject invention comprises a two-stage process. The first stage produces high quality monodispersed hydrous titania microsphere particles prepared by homogeneous precipitation via dielectric tuning in alcohol-water mixed solutions of inorganic salts. Titanium tetrachloride is used as an inorganic salt precursor material. The second stage converts the pure hydrous titania microsphere particles into crystalline barium titanate microsphere powders via low-temperature, hydrothermal reactions.

  20. Fatal Liver Damage After Barium Enemas Containing Tannic Acid

    PubMed Central

    Lucke, Hans H.; Hodge, Kenneth E.; Patt, Norman L.

    1963-01-01

    Tannic acid contained in the barium enema was found to have been the sole known potential hepatotoxin in four of the five cases of fulminating fatal liver failure that occurred in a 213-bed hospital over a period of 27 months. In the other case halothane anesthesia had also been administered. Autopsies (performed on four of the cases) did not suggest viral hepatitis but showed substantially indentical hepatic changes, not unlike those reported in the past following tannic acid exposure. Proof is not claimed that tannic acid was the cause of these deaths, but further investigation regarding the safety of its administration in barium enemas is advocated. ImagesFig. 1 PMID:14079135

  1. Ionization and expansion of barium clouds in the ionosphere

    NASA Technical Reports Server (NTRS)

    Ma, T.-Z.; Schunk, R. W.

    1993-01-01

    A recently envelope 3D model is used here to study the motion of the barium clouds released in the ionosphere, including the ionization stage. The ionization and the expansion of the barium clouds and the interaction between the clouds and the background ions are investigated using three simulations: a cloud without a directional velocity, a cloud with an initial velocity of 5 km/s across the B field, and a cloud with initial velocity components of 2 km/s both along and across the B field.

  2. Enhancement of the crystallinity of barium titanate by using a uniform barium-carbonate surface coating

    NASA Astrophysics Data System (ADS)

    Chung, Nak-Kwan; Yun, Ju-Young; Kim, Jin-Tae; Park, Jiho

    2017-05-01

    In this work, we modified the surfaces of BaTiO3 particles by using barium acetate and ammonium bicarbonate, and we studied the characteristics and sintering behaviors of the coated BaTiO3 particles. Transmission electron microscopy showed that the resultant coating layer was smooth and uniform without agglomerates. X-ray photoemission spectroscopy analysis also revealed that the surface coating layer was composed of BaCO3. After calcination at 950 °C for 5 hours, the c/ a ratio of the coated particles was found to have increased without size growth while the uncoated particles showed size growth. We finally found that the BaCO3 layer acted as a barrier to inhibit particle growth during calcination.

  3. Ferroelastic domains in lead-free barium zirconate titanate - barium calcium titanate piezoceramics

    NASA Astrophysics Data System (ADS)

    Ehmke, Matthias Claudius

    Piezoelectricity was first discovered by Pierre and Jaque Curie in the year 1880. Nowadays, piezoelectric materials are used in many application such as high voltage generation in gas igniters, actuation in micro-positioning devices, generation and detection of acoustic waves, emitters and receivers for sonar technology, ultrasonic cleaning, ultrasound medical therapy, and micropumps for ink-jet printers. The most commonly used piezoelectric material since the 1950's is the solid solution system lead zirconate titanate (PZT) that offers high piezoelectric performance under a large range of operating conditions. However, the toxicity of lead requires the replacement of PZT. The studied lead-free alternatives are commonly based on potassium sodium niobate (KNN) and bismuth sodium titanate (BNT), and more recently zirconium and calcium substituted barium titanate (BZT-BCT). The BZT-BCT system exhibits large piezoelectric coefficients that can exceed even those of most PZT compositions under certain conditions. Piezoelectricity was first discovered by Pierre and Jaque Curie in the year 1880. Nowadays, piezoelectric materials are used in many application such as high voltage generation in gas igniters, actuation in micro-positioning devices, generation and detection of acoustic waves, emitters and receivers for sonar technology, ultrasonic cleaning, ultrasound medical therapy, and micropumps for ink-jet printers. The most commonly used piezoelectric material since the 1950's is the solid solution system lead zirconate titanate (PZT) that offers high piezoelectric performance under a large range of operating conditions. However, the toxicity of lead requires the replacement of PZT. The studied lead-free alternatives are commonly based on potassium sodium niobate (KNN) and bismuth sodium titanate (BNT), and more recently zirconium and calcium substituted barium titanate (BZT-BCT). The BZT-BCT system exhibits large piezoelectric coefficients that can exceed even those of

  4. Phosphate homeostasis and disorders.

    PubMed

    Manghat, P; Sodi, R; Swaminathan, R

    2014-11-01

    Recent studies of inherited disorders of phosphate metabolism have shed new light on the understanding of phosphate metabolism. Phosphate has important functions in the body and several mechanisms have evolved to regulate phosphate balance including vitamin D, parathyroid hormone and phosphatonins such as fibroblast growth factor-23 (FGF23). Disorders of phosphate homeostasis leading to hypo- and hyperphosphataemia are common and have clinical and biochemical consequences. Notably, recent studies have linked hyperphosphataemia with an increased risk of cardiovascular disease. This review outlines the recent advances in the understanding of phosphate homeostasis and describes the causes, investigation and management of hypo- and hyperphosphataemia.

  5. Microbial solubilization of phosphate

    DOEpatents

    Rogers, R.D.; Wolfram, J.H.

    1993-10-26

    A process is provided for solubilizing phosphate from phosphate containing ore by treatment with microorganisms which comprises forming an aqueous mixture of phosphate ore, microorganisms operable for solubilizing phosphate from the phosphate ore and maintaining the aqueous mixture for a period of time and under conditions operable to effect the microbial solubilization process. An aqueous solution containing soluble phosphorus can be separated from the reacted mixture by precipitation, solvent extraction, selective membrane, exchange resin or gravity methods to recover phosphate from the aqueous solution. 6 figures.

  6. Microbial solubilization of phosphate

    DOEpatents

    Rogers, Robert D.; Wolfram, James H.

    1993-01-01

    A process is provided for solubilizing phosphate from phosphate containing ore by treatment with microorganisms which comprises forming an aqueous mixture of phosphate ore, microorganisms operable for solubilizing phosphate from the phosphate ore and maintaining the aqueous mixture for a period of time and under conditions operable to effect the microbial solubilization process. An aqueous solution containing soluble phosphorous can be separated from the reacted mixture by precipitation, solvent extraction, selective membrane, exchange resin or gravity methods to recover phosphate from the aqueous solution.

  7. Structure and properties of barium tin boro-phosphate glass systems with very low photoelastic constant

    NASA Astrophysics Data System (ADS)

    Itadani, M.; Tricot, G.; Doumert, B.; Takebe, H.; Saitoh, A.

    2017-08-01

    Glasses in the BaO-SnO-P2O5-B2O3 system were prepared and evaluated in order to formulate preform glasses suitable for the fabrication of fiber cores with a very low photoelastic constant. A first glass system (I: xBaO-(60-x)SnO-40P2O5) was designed with a constant P2O5 content and various BaO contents (0-40 mol. %). Introduction of 3 mol. % of B2O3 to enhance the glass stability leads to the second glass system (II: x'BaO-(57-x')SnO-40P2O5-3B2O3) with 33-38 mol. % BaO. The structure of both systems was investigated by 1D/2D magic-angle spinning nuclear magnetic resonance, Raman, and Fourier transform infrared spectroscopic techniques. 31P NMR showed the presence of Q2 and Q1 units in the first system and correlation 11B/31P NMR indicated that boron enters into the network as B(OP)4 structural units. The photoelastic constant was determined and the stability of the best formulations as well as their refractive index dispersion was established. The drawing temperature and isothermal heating time (without crystal precipitation) parameters were also accurately measured by using experimental time-temperature-transition. Considering that the refractive indices of the core and the cladding materials must match, detailed core and cladding compositions for a fiber enabling single-mode waveguide transmission were proposed.

  8. Effective adsorption of malachite green using magnetic barium phosphate composite from aqueous solution

    NASA Astrophysics Data System (ADS)

    Zhang, Fan; Wei, Zhong; Zhang, Wanning; Cui, Haiyan

    2017-07-01

    Magnetic Ba3(PO4)2/Fe3O4-nanoparticle (called BPFN) was prepared, characterized, and developed as a low-cost adsorbent for malachite green (MG) from aqueous solution. Factors such as adsorption temperature, pH of solution, dosage of adsorbent, adsorption kinetics and isotherms were investigated. The maximum adsorption capacity obtained in this work was 1639 mg g- 1 at 45 °C and pH 6. The adsorption process fitted the pseudo-first-order kinetic model and Langmuir isotherm model. Evidences from zeta potential, Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) data revealed that the adsorption process was driven by electrostatic attraction, the interaction between Lewis base sbnd N(CH3)2 in MG and Lewis acid Ba sites of BPFN. In addition, the BPFN could be easily regenerated by a magnet and the adsorption capacity maintained at 70% after five cycles. The present study suggests that the BPFN had high potential of removing MG from wastewater.

  9. Status of barium studies in the present era of oncology: Are they a history?

    PubMed Central

    Mahajan, Abhishek; Desai, Subash; Sable, Nilesh Pandurang; Thakur, Meenakshi Haresh

    2016-01-01

    With the advent of the modern imaging technologies, the present era of oncology is seeing steady decline in requests for barium studies due to the many reasons. It is prudent to mention here, that, barium examinations cannot be made obsolete! Our aim to preserve the age old technique of barium studies not only to keep it going on but also for the betterment and appropriate management of the patient. Our goal is not to “save” barium studies simply to keep this technology alive, per se, but rather to preserve barium radiology for the quality in patient care. PMID:28144086

  10. Glucose-6-phosphate dehydrogenase

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/003671.htm Glucose-6-phosphate dehydrogenase test To use the sharing features on this page, please enable JavaScript. Glucose-6-phosphate dehydrogenase (G6PD) is a protein that ...

  11. SEPARATION OF BARIUM VALUES FROM URANYL NITRATE SOLUTIONS

    DOEpatents

    Tompkins, E.R.

    1959-02-24

    The separation of radioactive barium values from a uranyl nitrate solution of neutron-irradiated uranium is described. The 10 to 20% uranyl nitrate solution is passed through a flrst column of a cation exchange resin under conditions favoring the adsorption of barium and certain other cations. The loaded resin is first washed with dilute sulfuric acid to remove a portion of the other cations, and then wash with a citric acid solution at pH of 5 to 7 to recover the barium along with a lesser amount of the other cations. The PH of the resulting eluate is adjusted to about 2.3 to 3.5 and diluted prior to passing through a smaller second column of exchange resin. The loaded resin is first washed with a citric acid solution at a pH of 3 to elute undesired cations and then with citric acid solution at a pH of 6 to eluts the barium, which is substantially free of undesired cations.

  12. PROPOSED ORAL REFERENCE DOSE (RFD) FOR BARIUM AND COMPOUNDS

    EPA Science Inventory

    The Integrated Risk Information System (IRIS) is a database of EPA's consensus opinion of the human health effects that may result from exposure to various substances found in the environment. A Toxicological Review and IRIS Summary were prepared for barium and compounds in 1998 ...

  13. Dynamics of a barium release in the magnetospheric tail

    NASA Technical Reports Server (NTRS)

    Mende, S. B.; Swenson, G. R.; Geller, S. P.; Doolittle, J. H.; Haerendel, G.

    1989-01-01

    The late time behavior of the May 13, 1985 magnetotail barium cloud is examined. The bulk dynamics of the cloud are studied based on triangulated data and data from Fabry-Perot Doppler velocity measurements. The changes in cloud morphology in relation to the in situ measurements made by the Ion Release Module satellite are discussed.

  14. Synthesis of phase pure praseodymium barium copper iron oxide.

    PubMed

    Konne, Joshua L; Davis, Sean A; Glatzel, Stefan; Hall, Simon R

    2013-06-18

    The control of crystallization of praseodymium barium copper iron oxide, an intermediate temperature solid oxide fuel cell cathode material, has been demonstrated for the first time using a biotemplated sol-gel synthesis technique. The results obtained showed significant improvement in purity, synthesis time, surface area and simplicity over that previously reported.

  15. Stabilization of arsenic- and barium-rich glass manufacturing waste

    SciTech Connect

    Fuessle, R.W.; Taylor, M.A.

    2000-03-01

    Effective solidification/stabilization (S/S) of arsenic- and barium-containing D004/D005 waste was accomplished by using a binder of cement with 40% class C fly ash and either ferrous sulfate or ferric sulfate as an additive. Addition of iron salts improves arsenic solidification/stabilization (S/S). Barium may be encapsulated within the stabilized matrix as barium sulfate. Recommended mole ratios for iron/arsenic and barium/sulfate are at least 6 and 1.2, respectively. A binder/waste ratio of 0.15 is volume efficient, but the mix design must be carefully controlled to achieve adequate S/S. In practice, the heterogeneity of waste and large-scale mix operations may preclude close control of reagent dosages, so a binder/waste ratio of 0.40 is preferable. Ferrous sulfate additive is preferable for arsenic S/S because it is effective over a wider range of mix designs and over a long-term curing period. Toxicity characteristic leaching procedure results degraded with long curing time for some mix designs with ferric sulfate additive.

  16. Effects of light exposure on irradiated barium fluoride crystals

    SciTech Connect

    Wuest, C.R.; Mauger, G.J.

    1993-04-20

    Small barium fluoride crystals have been irradiated using cobalt-60 gamma rays under various illumination conditions to establish the effect of photo-bleaching of the radiation-induced color centers. This paper describes results of a few different experiments conducted at LLNL over the past few weeks.

  17. Heavy ion recoil spectrometry of barium strontium titanate films

    NASA Astrophysics Data System (ADS)

    Stannard, W. B.; Johnston, P. N.; Walker, S. R.; Bubb, I. F.; Scott, J. F.; Cohen, D. D.; Dytlewski, N.; Martin, J. W.

    1995-05-01

    Thin films of barium strontium titanate have been analysed using heavy ion recoil spectrometry with 77 and 98 MeV 127I ions at the new heavy ion recoil facility at ANSTO, Lucas Heights. New calibration procedures have been developed for quantitative analysis. Energy spectra for each of the elements present reveal interdiffusion that was not previously known.

  18. Synthesis and surface properties of submicron barium sulfate particles

    NASA Astrophysics Data System (ADS)

    Zhang, Ming; Zhang, Bao; Li, Xinhai; Yin, Zhoulan; Guo, Xueyi

    2011-10-01

    Barium sulfate particles were synthesized in the presence of EDTA at room temperature. X-ray diffractometry (XRD), Fourier transform infrared resonance (FTIR) and scanning electron microscopy (SEM) were used to characterize the structure and morphology of BaSO 4 particles. The effect of the preparation parameters on the particle size distribution and morphology was investigated. The conditional formation constants of Ba-EDTA at different pH values were calculated. The results show that the size and morphology of BaSO 4 particles can be effectively controlled by adding EDTA in the precipitation process. Among all the operation conditions, the pH value has significant effect on the particle size. The obtained barium sulfate particles are spherical and well dispersed at pH = 9-10. Zeta potentials of BaSO 4 were measured at different pH. The isoelectric point (IEP) of barium sulfate colloid appears at pH 6.92. The model of the solid-solution interface at a particle of BaSO 4 was presented. The FTIR result indicates that the surface of the prepared BaSO 4 absorbs the functional groups of EDTA, which lower the IEP of the barium sulfate particles.

  19. Dose audit and evaluation of work practices during barium procedures using digital radiography techniques.

    PubMed

    Livingstone, Roshan S; Augustine, Philomina; Aparna, I; Raj, D Victor

    2004-10-01

    Effective dose and organ doses during barium procedures performed using digital radiography machines were estimated and the related work practices were evaluated. Measured values of dose area product (DAP) were used for the calculation of effective doses. One hundred and thirty eight patients undergoing barium procedures were included in the study. The use of additional 0.2 mm copper filter during barium procedures effectively reduced patient doses. The effective dose during barium swallow procedure varied from 0.03 mSv to 3.5 mSv; during barium meal it varied from 0.18 mSv to 2.62 mSv; and during barium enema it varied from 0.56 mSv to 4.24 mSv. Dose auditing was done on the basis of patient doses, imaging techniques and image quality. Selection of optimized exposure factors imparted lower dose to patients during barium procedures.

  20. Preliminary study of the CRRES magnetospheric barium releases

    NASA Technical Reports Server (NTRS)

    Huba, J. D.; Bernhardt, P. A.; Lyon, J. G.

    1992-01-01

    Preliminary theoretical and computational analyses of the Combined Release and Radiation Effects Satellite (CRRES) magnetospheric barium releases are presented. The focus of the studies is on the evolution of the diamagnetic cavity which is formed by the barium ions as they expand outward, and on the structuring of the density and magnetic field during the expansion phase of the releases. Two sets of simulation studies are discussed. The first set is based upon a 2D ideal MHD code and provides estimates of the time and length scales associated with the formation and collapse of the diamagnetic cavity. The second set uses a nonideal MHD code; specifically, the Hall term is included. This additional term is critical to the dynamics of sub-Alfvenic plasma expansions, such as the CRRES barium releases, because it leads to instability of the expanding plasma. Detailed simulations of the G4 and G10 releases were performed. In both cases the expanding plasma rapidly structured: the G4 release structured at time t less than about 3 s and developed scale sizes of about 1-2 km, while the G10 release structured at time t less than about 22 s and developed scale sizes of about 10-15 km. It is also found that the diamagnetic cavity size is reduced from those obtained from the ideal MHD results because of the structure. On the other hand, the structuring allows the formation of plasma blobs which appear to free stream across the magnetic field; thus, the barium plasma can propagate to larger distances traverse to the magnetic field than the case where no structuring occurs. Finally, a new normal mode of the system was discovered which may be excited at the leading edge of the expanding barium plasma.

  1. Why nature chose phosphates.

    PubMed

    Westheimer, F H

    1987-03-06

    Phosphate esters and anhydrides dominate the living world but are seldom used as intermediates by organic chemists. Phosphoric acid is specially adapted for its role in nucleic acids because it can link two nucleotides and still ionize; the resulting negative charge serves both to stabilize the diesters against hydrolysis and to retain the molecules within a lipid membrane. A similar explanation for stability and retention also holds for phosphates that are intermediary metabolites and for phosphates that serve as energy sources. Phosphates with multiple negative charges can react by way of the monomeric metaphosphate ion PO3- as an intermediate. No other residue appears to fulfill the multiple roles of phosphate in biochemistry. Stable, negatively charged phosphates react under catalysis by enzymes; organic chemists, who can only rarely use enzymatic catalysis for their reactions, need more highly reactive intermediates than phosphates.

  2. Phosphate, inositol and polyphosphates.

    PubMed

    Livermore, Thomas M; Azevedo, Cristina; Kolozsvari, Bernadett; Wilson, Miranda S C; Saiardi, Adolfo

    2016-02-01

    Eukaryotic cells have ubiquitously utilized the myo-inositol backbone to generate a diverse array of signalling molecules. This is achieved by arranging phosphate groups around the six-carbon inositol ring. There is virtually no biological process that does not take advantage of the uniquely variable architecture of phosphorylated inositol. In inositol biology, phosphates are able to form three distinct covalent bonds: phosphoester, phosphodiester and phosphoanhydride bonds, with each providing different properties. The phosphoester bond links phosphate groups to the inositol ring, the variable arrangement of which forms the basis of the signalling capacity of the inositol phosphates. Phosphate groups can also form the structural bridge between myo-inositol and diacylglycerol through the phosphodiester bond. The resulting lipid-bound inositol phosphates, or phosphoinositides, further expand the signalling potential of this family of molecules. Finally, inositol is also notable for its ability to host more phosphates than it has carbons. These unusual organic molecules are commonly referred to as the inositol pyrophosphates (PP-IPs), due to the presence of high-energy phosphoanhydride bonds (pyro- or diphospho-). PP-IPs themselves constitute a varied family of molecules with one or more pyrophosphate moiety/ies located around the inositol. Considering the relationship between phosphate and inositol, it is no surprise that members of the inositol phosphate family also regulate cellular phosphate homoeostasis. Notably, the PP-IPs play a fundamental role in controlling the metabolism of the ancient polymeric form of phosphate, inorganic polyphosphate (polyP). Here we explore the intimate links between phosphate, inositol phosphates and polyP, speculating on the evolution of these relationships. © 2016 Authors; published by Portland Press Limited.

  3. Design, testing, fabrication and launch support of a liquid chemical barium release payload (utilizing the liquid fluorine-barium salt/hydrazine system)

    NASA Technical Reports Server (NTRS)

    Stokes, C. S.; Smith, E. W.; Murphy, W. J.

    1972-01-01

    A payload was designed which included a cryogenic oxidizer tank, a fuel tank, and burner section. Release of 30 lb of chemicals was planned to occur in 2 seconds at the optimum oxidizer to fuel ratio. The chemicals consisted of 17 lb of liquid fluorine oxidizer and 13 lb of hydrazine-barium salt fuel mixture. The fuel mixture was 17% barium chloride, 16% barium nitrate, and 67% hydrazine, and contained 2.6 lb of available barium. Two significant problem areas were resolved during the program: explosive valve development and burner operation. The release payload was flight tested, from Wallops Island, Virginia. The release took place at an altitude of approximately 260 km. The release produced a luminous cloud which expanded very rapidly, disappearing to the human eye in about 20 seconds. Barium ion concentration slowly increased over a wide area of sky until measurements were discontinued at sunrise (about 30 minutes).

  4. Surface studies of barium and barium oxide on tungsten and its application to understanding the mechanism of operation of an impregnated tungsten cathode

    NASA Technical Reports Server (NTRS)

    Forman, R.

    1976-01-01

    Surface studies have been made of multilayer and monolayer films of barium and barium oxide on a tungsten substrate. The purpose of the investigation was to synthesize the surface conditions that exist on an activated impregnated tungsten cathode and obtain a better understanding of the mechanism of operation of such cathodes. The techniques employed in these measurements were Auger spectroscopy and work-function measurements. The results of this study show that the surface of an impregnated cathode is identical to that observed for a synthesized monolayer or partial monolayer of barium on oxidized tungsten by evaluating Auger spectra and work-function measurements. Data obtained from desorption studies of barium monolayers on a tungsten substrate in conjunction with Auger and work-function results have been interpreted to show that throughout most of its life an impreganated cathode has a partial monolayer, rather than a monolayer, of barium on its surface.

  5. Surface studies of barium and barium oxide on tungsten and its application to understanding the mechanism of operation of an impregnated tungsten cathode

    NASA Technical Reports Server (NTRS)

    Forman, R.

    1976-01-01

    Surface studies have been made of multilayer and monolayer films of barium and barium oxide on a tungsten substrate. The purpose of the investigation was to synthesize the surface conditions that exist on an activated impregnated tungsten cathode and obtain a better understanding of the mechanism of operation of such cathodes. The techniques employed in these measurements were Auger spectroscopy and work-function measurements. The results of this study show that the surface of an impregnated cathode is identical to that observed for a synthesized monolayer or partial monolayer of barium on oxidized tungsten by evaluating Auger spectra and work-function measurements. Data obtained from desorption studies of barium monolayers on a tungsten substrate in conjunction with Auger and work-function results have been interpreted to show that throughout most of its life an impreganated cathode has a partial monolayer, rather than a monolayer, of barium on its surface.

  6. Phosphate taxis in Pseudomonas aeruginosa.

    PubMed

    Kato, J; Ito, A; Nikata, T; Ohtake, H

    1992-08-01

    Pseudomonas aeruginosa was shown to be attracted to phosphate. The chemotactic response was induced by phosphate starvation. The specificity of chemoreceptors for phosphate was high so that no other tested phosphorus compounds elicited a chemotactic response as strong as that elicited by phosphate. Competition experiments showed that the chemoreceptors for phosphate appeared to be different from those for the common amino acids. Mutants constitutive for alkaline phosphatase showed the chemotactic response to phosphate regardless of whether the cells were starved for phosphate.

  7. Study of the photovoltaic effect in thin film barium titanate

    NASA Technical Reports Server (NTRS)

    Grannemann, W. W.; Dharmadhikari, V. S.

    1982-01-01

    Ferroelectric films of barium titanate were synthesized on silicon and quartz substrates, and the photoelectric effect in the structure consisting of metal deposited ferroelectric barium titanate film silicon was studied. A photovoltage with polarity that depends on the direction of the remanent polarization was observed. The deposition of BaTiO3 on silicon and fused quartz substrates was accomplished by an rf sputtering technique. A series of experiments to study the growth of ferroelectric BaTiO3 films on single crystal silicon and fused quartz substrates were conducted. The ferroelectric character in these films was found on the basis of evidence from the polarization electric field hysteresis loops, capacitance voltage and capacitance temperature techniques and from X-ray diffraction studies.

  8. Barium titanate nanoparticles: promising multitasking vectors in nanomedicine

    NASA Astrophysics Data System (ADS)

    Graziana Genchi, Giada; Marino, Attilio; Rocca, Antonella; Mattoli, Virgilio; Ciofani, Gianni

    2016-06-01

    Ceramic materials based on perovskite-like oxides have traditionally been the object of intense interest for their applicability in electrical and electronic devices. Due to its high dielectric constant and piezoelectric features, barium titanate (BaTiO3) is probably one of the most studied compounds of this family. Recently, an increasing number of studies have been focused on the exploitation of barium titanate nanoparticles (BTNPs) in the biomedical field, owing to the high biocompatibility of BTNPs and their peculiar non-linear optical properties that have encouraged their use as nanocarriers for drug delivery and as label-free imaging probes. In this review, we summarize all the recent findings about these ‘smart’ nanoparticles, including the latest, most promising potential as nanotransducers for cell stimulation.

  9. Numerical simulation of a radially injected barium cloud

    NASA Technical Reports Server (NTRS)

    Swift, D. W.; Wescott, E. M.

    1981-01-01

    Electrostatic two-dimensional numerical simulations of a radially symmetric barium injection experiment demonstrate that ions created by solar UV irradiation are electrostatically bound to the electrons which remain tied to the field lines on which they are created. Two possible instabilities are identified, but neither of them causes the barium plasma cloud to polarize in a way that would permit the plasma to keep up with the neutrals. In a second model, the velocity of the neutrals is allowed to be a function of the azimuthal angle. Here, a portion of the cloud does polarize in a way that allows a portion of the plasma to detach and move outward at the approximate speed of the neutrals. No rapid detachment is found when only the density of the neutrals is given an azimuthal asymmetry.

  10. Observations and theory of the AMPTE magnetotail barium releases

    NASA Technical Reports Server (NTRS)

    Bernhardt, P. A.; Roussel-Dupre, R. A.; Pongratz, M. B.; Haerendel, G.; Valenzuela, A.

    1987-01-01

    The barium releases in the magnetotail during the Active Magnetospheric Particle Tracer Explorers (AMPTE) operation were monitored by ground-based imagers and by instruments on the Ion Release Module. After each release, the data show the formation of a structured diamagnetic cavity. The cavity grows until the dynamic pressure of the expanding ions balances the magnetic pressure on its surface. The magnetic field inside the cavity is zero. The barium ions collect on the surface of the cavity, producing a shell. Plasma irregularities form along magnetic field lines draped over the surface of the cavity. The scale size of the irregularities is nearly equal to the thickness of the shell. The evolution and structuring of the diamagnetic cavity are modeled using magnetohydrodynamics theory.

  11. The Skylab barium plasma injection experiments. I - Convection observations

    NASA Technical Reports Server (NTRS)

    Wescott, E. M.; Stenbaek-Nielsen, H. C.; Davis, T. N.; Peek, H. M.

    1976-01-01

    Two barium-plasma injection experiments were carried out during magnetically active periods in conjunction with the Skylab 3 mission. The high-explosive shaped charges were launched near dawn on November 27 and December 4, 1973, UT. In both cases, the AE index was near 400 gammas, and extensive pulsating auroras covered the sky. The first experiment, Skylab Alpha, occurred in the waning phase of a 1000-gamma substorm, and the second, Skylab Beta, occurred in the expansive phase of an 800-gamma substorm. In both, the convection was generally magnetically eastward, with 100-km-level electric fields near 40 mV/m. However, in the Alpha experiment the observed orientation of the barium flux tube fit theoretical field lines having no parallel current, but the Beta flux-tube orientation indicated a substantial upward parallel sheet current.

  12. Redox processes in highly yttrium-doped barium titanate

    NASA Astrophysics Data System (ADS)

    Belous, Anatolii; V'yunov, Oleg; Kovalenko, Leonid; Makovec, Darko

    2005-05-01

    The changes of microstructure occurring during oxidation of the reduced form of yttrium-doped barium titanate (BaYxrad Ti1-x4+Tix3+O) have been studied. Samples were sintered under reduction conditions at P=10 Pa and oxidized by annealing at high temperatures (1150 and 1350 °C) in air. Depending on yttrium concentration, the oxidation of the reduced form of the yttrium-doped BaTiO 3 caused precipitation of the phase Ba 6Ti 17O 40 or the phases Ba 6Ti 17O 40 and Y 2Ti 2O 7. The precipitates had well-defined orientational relationships with the perovskite matrix. Oxidation of the reduced form of doped barium titanate results in formation of the phase BaYxrad Ti1-x/44+(VTi⁗)O responsible for increase in the resistance of outer grain layers, which lie between grain boundaries and grain.

  13. NASA/Max Planck Institute Barium Ion Cloud Project.

    NASA Technical Reports Server (NTRS)

    Brence, W. A.; Carr, R. E.; Gerlach, J. C.; Neuss, H.

    1973-01-01

    NASA and the Max Planck Institute for Extraterrestrial Physics (MPE), Munich, Germany, conducted a cooperative experiment involving the release and study of a barium cloud at 31,500 km altitude near the equatorial plane. The release was made near local magnetic midnight on Sept. 21, 1971. The MPE-built spacecraft contained a canister of 16 kg of Ba CuO mixture, a two-axis magnetometer, and other payload instrumentation. The objectives of the experiment were to investigate the interaction of the ionized barium cloud with the ambient medium and to deduce the properties of electric fields in the proximity of the release. An overview of the project is given to briefly summarize the organization, responsibilities, objectives, instrumentation, and operational aspects of the project.

  14. Photoionization and photoelectric loading of barium ion traps

    SciTech Connect

    Steele, A. V.; Churchill, L. R.; Griffin, P. F.; Chapman, M. S.

    2007-05-15

    Simple and effective techniques for loading barium ions into linear Paul traps are demonstrated. Two-step photoionization of neutral barium is achieved using a weak intercombination line (6s{sup 2} {sup 1}S{sub 0}{r_reversible}6s6p {sup 3}P{sub 1}, {lambda}=791 nm) followed by excitation above the ionization threshold using a nitrogen gas laser ({lambda}=337 nm). Isotopic selectivity is achieved by using a near Doppler-free geometry for excitation of the triplet 6s6p {sup 3}P{sub 1} state. Additionally, we report a particularly simple and efficient trap loading technique that employs an inexpensive uv epoxy curing lamp to generate photoelectrons.

  15. Dielectric function for doped graphene layer with barium titanate

    NASA Astrophysics Data System (ADS)

    Martinez Ramos, Manuel; Garces Garcia, Eric; Magana, Fernado; Vazquez Fonseca, Gerardo Jorge

    2015-03-01

    The aim of our study is to calculate the dielectric function for a system formed with a graphene layer doped with barium titanate. Density functional theory, within the local density approximation, plane-waves and pseudopotentials scheme as implemented in Quantum Espresso suite of programs was used. We considered 128 carbon atoms with a barium titanate cluster of 11 molecules as unit cell with periodic conditions. The geometry optimization is achieved. Optimization of structural configuration is performed by relaxation of all atomic positions to minimize their total energies. Band structure, density of states and linear optical response (the imaginary part of dielectric tensor) were calculated. We thank Dirección General de Asuntos del Personal Académico de la Universidad Nacional Autónoma de México, partial financial support by Grant IN-106514 and we also thank Miztli Super-Computing center the technical assistance.

  16. Synthesis and characterization of barium ferrite–silica nanocomposites

    SciTech Connect

    Aguilar-González, M.A.; Mendoza-Suárez, G.; Padmasree, K.P.

    2013-10-15

    In this work, we prepared barium ferrite-silica (BaM-SiO{sub 2}) nanocomposites of different molar ratios by high-energy ball milling, followed by heat-treatment at different temperatures. The microstructure, morphology and magnetic properties were characterized for different synthesis conditions by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). The results indicate that 15 h of milling was enough to avoid the generation of hematite phase and to get a good dispersion of barium ferrite particles in the ceramic matrix. For milling periods beyond 15 h and heat treatment above 900 °C, the XRD patterns showed the presence of hematite phase caused by the decomposition of BaM. The agglomerate size observed through SEM analysis was around 150 nm with a good BaM dispersion into the SiO{sub 2} matrix. The highest saturation magnetization (Ms) value obtained was 43 emu/g and the corresponding coercivity (Hc) value of 3.4 kOe for the composition 60BaM-40SiO{sub 2} milled for 15 h and heat treated at 900 °C. This coercivity value is acceptable for the application in magnetic recording media. Highlights: • Barium ferrite–silica nanocomposites were prepared by high energy ball milling. • Optimal processing time is 15 h milling and heat treatment at 900 °C. • This is enough to avoid the generation of hematite phase. • Obtain good dispersion of barium ferrite particles in the ceramic matrix • Above this processing time shows the presence of increased amount of hematite.

  17. Acute barium intoxication following ingestion of soap water solution.

    PubMed

    Joshi, Nandita; Sharma, Chhavi Sarabpreert; Sai; Sharma, Jai Prakash

    2012-10-01

    We present a rare case in which a young girl ingested a solution of a hair-removing soap. The ingestion resulted in profound hypokalemia and severe acidosis leading to flaccid paralysis, respiratory arrest and ventricular arrhythmias. Ultimately the patient made complete recovery. The soapwas found to contain barium sulfide. The degree of paralysis and acidosis appeared to be directly related to serum potassium levels.

  18. Acute barium intoxication following ingestion of soap water solution

    PubMed Central

    Joshi, Nandita; Sharma, Chhavi Sarabpreert; Sai; Sharma, Jai Prakash

    2012-01-01

    We present a rare case in which a young girl ingested a solution of a hair-removing soap. The ingestion resulted in profound hypokalemia and severe acidosis leading to flaccid paralysis, respiratory arrest and ventricular arrhythmias. Ultimately the patient made complete recovery. The soapwas found to contain barium sulfide. The degree of paralysis and acidosis appeared to be directly related to serum potassium levels. PMID:23559738

  19. Complex Impedance Studies of Optically Excited Strontium Barium Niobate

    DTIC Science & Technology

    2007-11-02

    has a tetragonal tungsten - bronze structure. The unit cell for this structure, illustrated below in Fig. 2.1, consists of ten oxygen octahedra joined...4 Kittel, pp. 373-374. 5 P. B. Jamieson, et al, “Ferroelectric Tungsten Bronze -Type Crystal Structures. I. Barium Strontium Niobate...Oxford, 1987). 2. C. Kittel, Introduction to Solid State Physics, (Wiley, New York, 1986). 3. P. B. Jamieson, et al, “Ferroelectric Tungsten

  20. Barium borohydride chlorides: synthesis, crystal structures and thermal properties.

    PubMed

    Grube, Elisabeth; Olesen, Cathrine H; Ravnsbæk, Dorthe B; Jensen, Torben R

    2016-05-10

    Here we report the synthesis, mechanism of formation, characterization and thermal decomposition of new barium borohydride chlorides prepared by mechanochemistry and thermal treatment of MBH4-BaCl2, M = Li, Na or K in ratios 1 : 1 and 1 : 2. Initially, orthorhombic barium chloride, o-BaCl2 transforms into o-Ba(BH4)xCl2-x, x ∼ 0.15. Excess LiBH4 leads to continued anion substitution and a phase transformation into hexagonal barium borohydride chloride h-Ba(BH4)xCl2-x, which accommodates higher amounts of borohydride, possibly x ∼ 0.85 and resembles h-BaCl2. Thus, two solid solutions are in equilibrium during mechano-chemical treatment of LiBH4-BaCl2 (1 : 1) whereas LiBH4-BaCl2 (2 : 1) converts to h-Ba(BH4)0.85Cl1.15. Upon thermal treatment at T > ∼200 °C, h-Ba(BH4)0.85Cl1.15 transforms into another orthorhombic barium borohydride chloride compound, o-Ba(BH4)0.85Cl1.15, which is structurally similar to o-BaBr2. The samples with M = Na and K have lower reactivity and form o-Ba(BH4)xCl2-x, x ∼ 0.1 and a solid solution of sodium chloride dissolved in solid sodium borohydride, Na(BH4)1-xClx, x = 0.07. The new compounds and reaction mechanisms are investigated by in situ synchrotron radiation powder X-ray diffraction (SR-PXD), Fourier transform infrared spectroscopy (FT-IR) and simultaneous thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), mass spectroscopy (MS) and temperature programmed photographic analysis (TPPA).

  1. Barium hexaferrite based on the waste products from electroplating processes

    SciTech Connect

    Vlasov, A.S.; Stepanchikova, I.G.; Makarov, S.V.; Zaitsev, V.A.; Danilov, A.S.

    1987-11-01

    The authors assess the possibility of simultaneously treating and using waste electroplating slurries containing large amounts of iron hydroxides for obtaining barium hexaferrite ceramics. Differential thermal analysis was employed to determine the processing and recovery parameters and the resulting hexaferrites were tested, mechanically and by x-ray diffraction, for their mechanical and magnetic properties as well as for their phase composition and structure. The consequences of the process on pollution abatement are also evaluated.

  2. Texture and Microstructural Development in Gelcast Barium Hexaferrite

    SciTech Connect

    Hovis, David B.; Faber, Katherine T.; Kenik, Edward A

    2008-01-01

    The development of texture in barium hexaferrite by templated grain growth was studied as a function of the Fe2O3/BaCO3 ratio, B2O3 additions in the starting materials, and sintering temperature. A magnetic field was used to orient the template particles during the gelcasting process. Excess BaCO3 resulted in abnormal grain growth and maximized texture, while B2O3 additions promoted coarsening, but no abnormal grain growth.

  3. Barium isotopes in chondritic meteorites: implications for planetary reservoir models.

    PubMed

    Ranen, Michael C; Jacobsen, Stein B

    2006-11-03

    High-precision barium isotope measurements yielded differences of up to 25 parts per million in the 137Ba/136Ba ratio and 60 parts per million in the 138Ba/136Ba ratio between chondrites and Earth. These differences probably arose from incomplete mixing of nucleosynthetic material in the solar nebula. Chondritic meteorites have a slight excess of supernova-derived material as compared to Earth, demonstrating that the solar nebula was not perfectly homogenized upon formation.

  4. Barium isotopes reveal role of ocean circulation on barium cycling in the Atlantic

    NASA Astrophysics Data System (ADS)

    Bates, Stephanie L.; Hendry, Katharine R.; Pryer, Helena V.; Kinsley, Christopher W.; Pyle, Kimberley M.; Woodward, E. Malcolm S.; Horner, Tristan J.

    2017-05-01

    We diagnose the relative influences of local-scale biogeochemical cycling and regional-scale ocean circulation on Atlantic barium cycling by analysing four new depth profiles of dissolved Ba concentrations and isotope compositions from the South and tropical North Atlantic. These new profiles exhibit systematic vertical, zonal and meridional variations that reflect the influence of both local-scale barite cycling and large-scale ocean circulation. Epipelagic decoupling of dissolved Ba and Si reported previously in the tropics is also found to be associated with significant Ba isotope heterogeneity. As such, we contend that this decoupling originates from the depth segregation of opal and barite formation but is exacerbated by weak vertical mixing. Zonal influence from isotopically-'heavy' water masses in the western North Atlantic evidence the advective inflow of Ba-depleted Upper Labrador Sea Water, which is not seen in the eastern basin or the South Atlantic. Meridional variations in Atlantic Ba isotope systematics below 2000 m appear entirely controlled by conservative mixing. Using an inverse isotopic mixing model, we calculate the Ba isotope composition of the Ba-poor northern end-member as +0.45 ‰ and the Ba-rich southern end-member +0.26 ‰, relative to NIST SRM 3104a. The near-conservative behaviour of Ba below 2000 m indicates that Ba isotopes can serve as an independent tracer of the provenance of northern- versus southern-sourced water masses in the deep Atlantic Ocean. This finding may prove useful in palaeoceanographic studies, should appropriate sedimentary archives be identified, and offers new insights into the processes that cycle Ba in seawater.

  5. Life Model of Hollow Cathodes Using a Barium Calcium Aluminate Impregnated Tungsten Emitter

    NASA Technical Reports Server (NTRS)

    Kovaleski, S. D.; Burke, Tom (Technical Monitor)

    2001-01-01

    Hollow cathodes with barium calcium aluminate impregnated tungsten emitters for thermionic emission are widely used in electric propulsion. These high current, low power cathodes are employed in ion thrusters, Hall thrusters, and on the International Space Station in plasma contactors. The requirements on hollow cathode life are growing more stringent with the increasing use of electric propulsion technology. The life limiting mechanism that determines the entitlement lifetime of a barium impregnated thermionic emission cathode is the evolution and transport of barium away from the emitter surface. A model is being developed to study the process of barium transport and loss from the emitter insert in hollow cathodes. The model accounts for the production of barium through analysis of the relevant impregnate chemistry. Transport of barium through the approximately static gas is also being treated. Finally, the effect of temperature gradients within the cathode are considered.

  6. The Tordo 1 polar cusp barium plasma injection experiment

    NASA Technical Reports Server (NTRS)

    Wescott, E. M.; Stenbaek-Nielsen, H. C.; Davis, T. N.; Jeffries, R. A.; Roach, W. H.

    1978-01-01

    In January 1975, two barium plasma injection experiments were carried out with rockets launched into the upper atmosphere where field lines from the dayside cusp region intersect the ionosphere. The Tordo 1 experiment took place near the beginning of a worldwide magnetic storm. It became a polar cap experiment almost immediately as convection perpendicular to the magnetic field moved the fluorescent plasma jet away from the cusp across the polar cap in an antisunward direction. Convection across the polar cap with an average velocity of more than 1 km/s was observed for nearly 40 min until the barium flux tubes encountered large electron fields associated with a poleward bulge of the auroral oval near Greenland. Prior to the encounter with the aurora near Greenland there is evidence of upward acceleration of the barium ions while they were in the polar cap. The three-dimensional observations of the plasma orientation and motion give an insight into convection from the cusp region across the polar cap, the orientation of the polar cap magnetic field lines out to several earth radii, the causes of polar cap magnetic perturbations, and parallel acceleration processes.

  7. Barium thiolates and selenolates: syntheses and structural principles.

    PubMed

    Ruhlandt-Senge, K; Englich, U

    2000-11-17

    The synthesis and structural characterization of a family of barium thiolates and selenolates is described. The thiolates were synthesized by metallation of thiols, the selenolates by reductive insertion of the metal into the selenium-selenium bond of diorganodiselenides. Both reaction sequences were carried out by using barium metal dissolved in ammonia; this afforded barium thiolates and selenolates in good yield and purity. The structural principles displayed in the target compounds span a wide range of solid-state formulations, including monomeric and dimeric species, and separated ion triples, namely [Ba(thf)4(SMes*)2] (1; Mes* = 2,4,6-tBU3C6H2), [Ba(thf)4(SeMes*)2] (2), [Ba([18]crown-6)(hmpa)2][(SeMes*)2] (3), the dimeric [(Ba(py)3(thf)(SeTrip)2)2] (4; py = pyridine, Trip = 2,4.6-iPr3C6H2), and [Ba([18]crown-6)(SeTrip)2] (5). The full range of association modes is completed by [Ba([18]crown-6)(hmpa)SMes*][SMes*] (6) communicated earlier by this group. In the solid state, this compound displays an intermediate ion coordination mode: one anion is bound to the metal, while the second one is unassociated. Together these compounds provide structural information about all three different association modes for alkaline earth metal derivatives. This collection of structural data allows important conclusions about the influence of solvation and ligation on structural trends.

  8. Barium as a potential indicator of phosphorus in agricultural runoff.

    PubMed

    Ahlgren, Joakim; Djodjic, Faruk; Wallin, Mats

    2012-01-01

    In many catchments, anthropogenic input of contaminants, and in particular phosphorus (P), into surface water is a mixture of agricultural and sewage runoff. Knowledge about the relative contribution from each of these sources is vital for mitigation of major environmental problems such as eutrophication. In this study, we investigated whether the distribution of trace elements in surface waters can be used to trace the contamination source. Water from three groups of streams was investigated: streams influenced only by agricultural runoff, streams influenced mainly by sewage runoff, and reference streams. Samples were collected at different flow regimes and times of year and analyzed for 62 elements using ICP-MS. Our results show that there are significant differences between the anthropogenic sources affecting the streams in terms of total element composition and individual elements, indicating that the method has the potential to trace anthropogenic impact on surface waters. The elements that show significant differences between sources are strontium (p < 0.001), calcium (p < 0.004), potassium (p < 0.001), magnesium (p < 0.001), boron (p < 0.001), rhodium (p = 0.001), and barium (p < 0.001). According to this study, barium shows the greatest potential as a tracer for an individual source of anthropogenic input to surface waters. We observed a strong relationship between barium and total P in the investigated samples (R(2) = 0.78), which could potentially be used to apportion anthropogenic sources of P and thereby facilitate targeting of mitigation practices.

  9. Toward remote ion-ion entanglement with barium

    NASA Astrophysics Data System (ADS)

    Noel, Thomas W.; Auchter, Carolyn; Chou, Chen-Kuan; Blinov, Boris B.

    2015-03-01

    We present work toward remote entanglement of barium ions in traps separated by a few meters. A new version of an ion trap specialized for remote entanglement is introduced. The new trap allows for highly efficient collection of ion fluorescence while simultaneously minimizing ion micromotion and aligning the trap position precisely to the focus of an in-vacuum parabolic mirror by using a set of bias electrodes and a piezoelectric micro-positioning system. The success rate of the remote entanglement procedure depends strongly on the efficiency with which ion fluorescence can be coupled into an optical fiber. Characterization of our system in terms of ion fluorescence collection and fiber coupling efficiency is presented. Results demonstrating entanglement between a single barium ion and single spontaneously emitted photons are shown. The entanglement fidelity of the ion-photon state is measured to be 0.84(1) and a CHSH Bell signal of 2.303(36) finds violation of the CHSH version of the Bell inequality by over eight standard deviations. Barium's relatively long wavelength transitions make it an ideal candidate for our longer term goal of remote entanglement of ions separated by a kilometer or more. Such long distance remote entanglement should allow for a loophole-free verification of the violation of the Bell inequality.

  10. Optical, mechanical, and thermal properties of barium borate

    NASA Astrophysics Data System (ADS)

    Eimerl, D.; Davis, L.; Velsko, S.; Graham, E. K.; Zalkin, A.

    1987-09-01

    We report measurements of all the material constants necessary to fully characterize barium borate as a nonlinear optical material. All data was taken on crystals supplied by Professor Chuangtien Chen, Fuzhou, People's Republic of China. We have determined the crystal structure, the optical absorption, the refractive indices from the UV to the near IR, the thermo-optic coefficients, the nonlinear optical or coefficients, the resistance to laser damage, the elastic constants, the thermal expansion, thermal conductivity and dielectric constants, and the fracture toughness. This data is used to evaluate barium borate for a variety of applications. We find that, in general, barium borate has a low acceptance angle, and that despite its higher optical nonlinearity, it is therefore not significantly more efficient than other commonly available materials, except in the UV below 250 nm. On the other hand, it has a high damage threshold, it is physically robust, it has good UV and IR transparency, and it has excellent average power capability. It permits deep UV generation, and has great potential for generating tunable visible and IR light as an optical parametric amplifier.

  11. Zinc phosphate conversion coatings

    DOEpatents

    Sugama, T.

    1997-02-18

    Zinc phosphate conversion coatings for producing metals which exhibit enhanced corrosion prevention characteristics are prepared by the addition of a transition-metal-compound promoter comprising a manganese, iron, cobalt, nickel, or copper compound and an electrolyte such as polyacrylic acid, polymethacrylic acid, polyitaconic acid and poly-L-glutamic acid to a phosphating solution. These coatings are further improved by the incorporation of Fe ions. Thermal treatment of zinc phosphate coatings to generate {alpha}-phase anhydrous zinc phosphate improves the corrosion prevention qualities of the resulting coated metal. 33 figs.

  12. Zinc phosphate conversion coatings

    DOEpatents

    Sugama, Toshifumi

    1997-01-01

    Zinc phosphate conversion coatings for producing metals which exhibit enhanced corrosion prevention characteristics are prepared by the addition of a transition-metal-compound promoter comprising a manganese, iron, cobalt, nickel, or copper compound and an electrolyte such as polyacrylic acid, polymethacrylic acid, polyitaconic acid and poly-L-glutamic acid to a phosphating solution. These coatings are further improved by the incorporation of Fe ions. Thermal treatment of zinc phosphate coatings to generate .alpha.-phase anhydrous zinc phosphate improves the corrosion prevention qualities of the resulting coated metal.

  13. Atomic force microscopy studies of twins in yttrium-doped barium titanate

    NASA Astrophysics Data System (ADS)

    Gheno, Simoni Maria; Hasegawa, Haroldo Lhou; Filho, Pedro Iris Paulin

    2006-11-01

    Barium titanate is the main constituent of PTC materials and their electric properties are sensitive to microstructure and defects, in atomic scale, that are significantly affected by processing parameters. The microstructure of barium titanate doped with yttrium was investigated using topographic images obtained by AFM in contact mode. The AFM images of barium titanate doped with yttrium showed the effect of large grains with double twins at different (1 1 1) planes.

  14. Thermochemical decomposition of water based on reactions of chromium and barium compounds.

    PubMed

    Bamberger, C E; Richardson, D M; Bredig, M A; Cheng, K

    1975-08-29

    A potentially useful thermochemical cycle developed for the production of hydrogen and oxygen from water consists of three chemical reactions that take place in the temperature range from 400 degrees to 1200 degrees K. The oxidation and reduction of chromium compounds by barium hydroxide and the hydrolytic disproportionation of barium chromate(IV) and barium chromate(V), the reactions which constitute the proposed cycle, have been demonstrated.

  15. Radiation losses in microwave Ku region by conducting pyrrole/barium titanate and barium hexaferrite based nanocomposites

    NASA Astrophysics Data System (ADS)

    Kaur, Talwinder; Kumar, Sachin; Narang, S. B.; Srivastava, A. K.

    2016-12-01

    Nanocomposites of substituted barium hexaferrite and barium titanate embedded in a polymer were synthesized via emulsion polymerization. The study was performed by using X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, electron spin resonance spectroscopy, a vibrating sample magnetometer and a vector network analyzer. It is found that maximum radiation loss occur at 16.09 GHz (-14.23 dB) frequency owing to the combined effect of conducting polymer, suitable dielectric and magnetic material. This suggests that prepared material is suitable for radiation losses. Micro structural study reveals the presence of all the phases of the compounds comprises composite. Benzene ring absorption band (at 1183 cm-1) in FT-IR spectra illustrates the presence of polymer. Surface morphology reveals the presence of array of particles encapsulated by the polymer.

  16. Electric field tunable 60 GHz ferromagnetic resonance response in barium ferrite-barium strontium titanate multiferroic heterostructures

    NASA Astrophysics Data System (ADS)

    Song, Young-Yeal; Das, Jaydip; Krivosik, Pavol; Mo, Nan; Patton, Carl E.

    2009-05-01

    A magnetic-ferroelectric film heterostructure with a large electric field tuning of the ferromagnetic resonance (FMR) mode was fabricated. Pulse laser deposited 30 nm thick Pt electrodes and 3 μm thick barium strontium titanate films on Nb-doped strontium titanate substrates were capped with an unbonded 200 μm thick single crystal in-plane c-axis barium hexaferrite slab. The structure gives a 60 GHz FMR frequency shift of 16 MHz at a bias of 29 V, for an average response of 0.55 MHz/V. The maximum incremental tuning response at 29 V was 1.3 MHz/V. This is a hundredfold improvement over previous results.

  17. Sponge-associated bacteria mineralize arsenic and barium on intracellular vesicles

    PubMed Central

    Keren, Ray; Mayzel, Boaz; Lavy, Adi; Polishchuk, Iryna; Levy, Davide; Fakra, Sirine C.; Pokroy, Boaz; Ilan, Micha

    2017-01-01

    Arsenic and barium are ubiquitous environmental toxins that accumulate in higher trophic-level organisms. Whereas metazoans have detoxifying organs to cope with toxic metals, sponges lack organs but harbour a symbiotic microbiome performing various functions. Here we examine the potential roles of microorganisms in arsenic and barium cycles in the sponge Theonella swinhoei, known to accumulate high levels of these metals. We show that a single sponge symbiotic bacterium, Entotheonella sp., constitutes the arsenic- and barium-accumulating entity within the host. These bacteria mineralize both arsenic and barium on intracellular vesicles. Our results indicate that Entotheonella sp. may act as a detoxifying organ for its host. PMID:28233852

  18. CADMIUM PHOSPHATE GLASS

    DOEpatents

    Carpenter, H.W.; Johnson, P.D.

    1963-04-01

    A method of preparing a cadmium phosphate glass that comprises providing a mixture of solid inorganic compounds of cadmuim and phosphate having vaporizable components and heating the resulting composition to a temperature of at least 850 un. Concent 85% C is presented. (AEC)

  19. A review of the health impacts of barium from natural and anthropogenic exposure.

    PubMed

    Kravchenko, Julia; Darrah, Thomas H; Miller, Richard K; Lyerly, H Kim; Vengosh, Avner

    2014-08-01

    There is an increasing public awareness of the relatively new and expanded industrial barium uses which are potential sources of human exposure (e.g., a shale gas development that causes an increased awareness of environmental exposures to barium). However, absorption of barium in exposed humans and a full spectrum of its health effects, especially among chronically exposed to moderate and low doses of barium populations, remain unclear. We suggest a systematic literature review (from 1875 to 2014) on environmental distribution of barium, its bioaccumulation, and potential and proven health impacts (in animal models and humans) to provide the information that can be used for optimization of future experimental and epidemiological studies and developing of mitigative and preventive strategies to minimize negative health effects in exposed populations. The potential health effects of barium exposure are largely based on animal studies, while epidemiological data for humans, specifically for chronic low-level exposures, are sparse. The reported health effects include cardiovascular and kidney diseases, metabolic, neurological, and mental disorders. Age, race, dietary patterns, behavioral risks (e.g., smoking), use of medications (those that interfere with absorbed barium in human organism), and specific physiological status (e.g., pregnancy) can modify barium effects on human health. Identifying, evaluating, and predicting the health effects of chronic low-level and moderate-level barium exposures in humans is challenging: Future research is needed to develop an understanding of barium bioaccumulation in order to mitigate its potential health impacts in various exposured populations. Further, while occupationally exposed at-risk populations exist, it is also important to identify potentially vulnerable subgroups among non-occupationally exposed populations (e.g., elderly, pregnant women, children) who are at higher risk of barium exposure from drinking water and food.

  20. Tungsten and barium transport in the internal plasma of hollow cathodes

    NASA Astrophysics Data System (ADS)

    Polk, James E.; Mikellides, Ioannis G.; Katz, Ira; Capece, Angela M.

    2009-06-01

    The effect of tungsten erosion, transport, and redeposition on the operation of dispenser hollow cathodes was investigated in detailed examinations of the discharge cathode inserts from 8200 h and 30 352 h ion engine wear tests. Erosion and subsequent redeposition of tungsten in the electron emission zone at the downstream end of the insert reduce the porosity of the tungsten matrix, preventing the flow of barium from the interior. This inhibits the interfacial reactions of the barium-calcium-aluminate impregnant with the tungsten in the pores. A numerical model of barium transport in the internal xenon discharge plasma shows that the barium required to reduce the work function in the emission zone can be supplied from upstream through the gas phase. Barium that flows out of the pores of the tungsten insert is rapidly ionized in the xenon discharge and pushed back to the emitter surface by the electric field and drag from the xenon ion flow. This barium ion flux is sufficient to maintain a barium surface coverage at the downstream end greater than 0.6, even if local barium production at that point is inhibited by tungsten deposits. The model also shows that the neutral barium pressure exceeds the equilibrium vapor pressure of the impregnant decomposition reaction over much of the insert length, so the reactions are suppressed. Only a small region upstream of the zone blocked by tungsten deposits is active and supplies the required barium. These results indicate that hollow cathode failure models based on barium depletion rates in vacuum dispenser cathodes are very conservative.

  1. PHOSPHATE MANAGEMENT: FY2010 RESULTS OF PHOSPHATE PRECIPITATION TESTS

    SciTech Connect

    Hay, M.; King, W.

    2011-04-04

    The Phosphate Management program seeks to develop treatment options for caustic phosphate solutions resulting from the caustic leaching of the bismuth phosphate sludge. The SRNL subtask investigated the precipitation of phosphate salts from caustic solutions through addition of fluoride and by crystallization. The scoping tests examined the: precipitation of phosphate by the addition of sodium fluoride to form the sodium fluorophosphate double salt, Na{sub 7}F(PO{sub 4}){sub 2} {center_dot} 19H{sub 2}O, crystallization of phosphate by reducing the temperature of saturated phosphate solutions, and combinations of precipitation and crystallization. A simplified leachate simulant was used in the study produced by dissolving sodium phosphate in 1 M to 3.5 M sodium hydroxide solutions. The results show that all three processes; precipitation with sodium fluoride, crystallization, and combined precipitation/crystallization can be effective for removing large amounts of phosphate from solution. The combined process of precipitation/crystallization showed >90% removal of phosphate at all hydroxide concentrations when cooling a non-saturated phosphate solution from 65 C to 25 C. Based on the measured solubility of sodium phosphate, pH adjustment/caustic addition will also remove large amounts of phosphate from solution (>80%). For all three processes, the phosphate concentration in the caustic solution must be managed to keep the phosphate from becoming too concentrated and thereby potentially forming a solid mass of sodium phosphate after an effective phosphate removal process.

  2. The effect of barium on perceptions of taste intensity and palatability

    PubMed Central

    Dietsch, Angela M.; Solomon, Nancy Pearl; Steele, Catriona M.; Pelletier, Cathy A.

    2015-01-01

    Purpose Barium may affect the perception of taste intensity and palatability. Such differences are important considerations in the selection of dysphagia assessment strategies and interpretation of results. Methods Eighty healthy women grouped by age (younger, older) and genetic taste status (supertaster, non-taster) rated intensity and palatability for seven tastants prepared in deionized water with and without 40% w/v barium: non-carbonated and carbonated water, diluted ethanol, and high concentrations of citric acid (sour), sodium chloride (salty), caffeine (bitter) and sucrose (sweet). Mixed model analyses explored the effects of barium, taster status, and age on perceived taste intensity and acceptability of stimuli. Results Barium was associated with lower taste intensity ratings for sweet, salty, and bitter tastants, higher taste intensity in carbonated water, and lower palatability in water, sweet, sour, and carbonated water. Older subjects reported lower palatability (all barium samples, sour) and higher taste intensity scores (ethanol, sweet, sour) compared to younger subjects. Supertasters reported higher taste intensity (ethanol, sweet, sour, salty, bitter) and lower palatability (ethanol, salty, bitter) than non-tasters. Refusal rates were highest for younger subjects and supertasters, and for barium (regardless of tastant), bitter, and ethanol. Conclusions Barium suppressed the perceived intensity of some tastes and reduced palatability. These effects are more pronounced in older subjects and supertasters, but younger supertasters are least likely to tolerate trials of barium and strong tastant solutions. PMID:24037100

  3. Lack of effect of drinking water barium on cardiovascular risk factors.

    PubMed

    Wones, R G; Stadler, B L; Frohman, L A

    1990-04-01

    Higher cardiovascular mortality has been associated in a single epidemiological study with higher levels of barium in drinking water. The purpose of this study was to determine whether drinking water barium at levels found in some U.S. communities alters the known risk factors for cardiovascular disease. Eleven healthy men completed a 10-week dose-response protocol in which diet was controlled (600 mg cholesterol; 40% fat, 40% carbohydrate, 20% protein; sodium and potassium controlled at the subject's pre-protocol estimated intake). Other aspects of the subjects' lifestyles known to affect cardiac risk factors were controlled, and the barium content (as barium chloride) of the drinking water (1.5 L/day) was varied from 0 (first 2 weeks), to 5 ppm (next 4 weeks), to 10 ppm (last 4 weeks). Multiple blood and urine samples, morning and evening blood pressure measurements, and 48-hr electrocardiographic monitoring were performed at each dose of barium. There were no changes in morning or evening systolic or diastolic blood pressures, plasma cholesterol or lipoprotein or apolipoprotein levels, serum potassium or glucose levels, or urine catecholamine levels. There were no arrhythmias related to barium exposure detected on continuous electrocardiographic monitoring. A trend was seen toward increased total serum calcium levels with exposure to barium, which was of borderline statistical significance and of doubtful clinical significance. In summary, drinking water barium at levels of 5 and 10 ppm did not appear to affect any of the known modifiable cardiovascular risk factors.

  4. Lack of effect of drinking water barium on cardiovascular risk factors

    SciTech Connect

    Wones, R.G.; Stadler, B.L.; Frohman, L.A. )

    1990-04-01

    Higher cardiovascular mortality has been associated in a single epidemiological study with higher levels of barium in drinking water. The purpose of this study was to determine whether drinking water barium at levels found in some U.S. communities-alters the known risk factors for cardiovascular disease. Eleven healthy men completed a 10-week dose-response protocol in which diet was controlled. Other aspects of the subjects' lifestyles known to affect cardiac risk factors were controlled, and the barium content (as barium chloride) of the drinking water was varied from 0, to 5 ppm, to 10 ppm. Multiple blood and urine samples, morning and evening blood pressure measurements, and 48-hr electrocardiographic monitoring were performed at each dose of barium. There were no changes in morning or evening systolic or diastolic blood pressures, plasma cholesterol or lipoprotein or apolipoprotein levels, serum potassium or glucose levels, or urine catecholamine levels. There were no arrythmias related to barium exposure detected on continuous electrocardiographic monitoring. A trend was seen toward increased total serum calcium levels with exposure to barium, which was of borderline statistical significance and of doubtful clinical significance. In summary, drinking water barium at levels of 5 and 10 ppm did not appear to affect any of the known modifiable cardiovascular risk factors.

  5. Replacement of SR 4990 by Barium Styphnate in the Mk 24 Actuator

    DTIC Science & Technology

    the SR-4990 in the Mk 24 Actuator. Experimental work was performed with barium styphnate , lead mononitroresorcinate, and two manufactured powders...Candidate materials were first screened using a pressure bomb. Final testing was performed in the Mk 24 Actuator design. Test results showed that of the four candidates, barium styphnate is the best material for the Actuator Mk 24.

  6. Comparison of standardized bariums with varying rheological parameters on swallowing kinematics in males.

    PubMed

    Hind, Jacqueline; Divyak, Elizabeth; Zielinski, Jill; Taylor, Andrew; Hartman, Michael; Gangnon, Ronald; Robbins, Joanne

    2012-01-01

    This study measured dose-response of a range of commercially available liquid barium materials designed for use in videofluoroscopic oropharyngeal swallowing assessments, particularly as they relate to the necessity of adding a thickening agent for swallow safety. A group of 25 adult males representing various medical diagnoses consented to participate, with 16 qualifying to complete a videofluoroscopic swallowing assessment with liquid barium materials of three viscosities (nectar: 300 cP, thin honey: 1,500 cP, thick honey: 3,000 cP). Outcome measures included airway invasion (Penetration-Aspiration score), postswallow residue, and patient preference. Penetration-Aspiration and residue scores did not significantly differ between thin honey and thick honey bariums. Significantly more severe airway invasion was observed with nectar boluses than with two levels of honey boluses (p < 0.001). Significantly more residue was observed in the oral cavity (p < 0.002) and valleculae (p < 0.001) with thin and thick honey bariums than with nectar barium. Thin honey was rated as "easy" or "average" to drink by 67% of subjects, compared with 54% for thick honey. This study supports the use of thin honey barium over thick honey barium during videofluoroscopic swallowing assessments because the two honey bariums were comparable in terms of airway protection and postswallow residue in the oropharynx and the thin honey was preferred by patients.

  7. Barium versus nonbarium stimuli: differences in taste intensity, chemesthesis, and swallowing behavior in healthy adult women.

    PubMed

    Nagy, Ahmed; Steele, Catriona M; Pelletier, Cathy A

    2014-06-01

    The authors examined the impact of barium on the perceived taste intensity of 7 different liquid tastant stimuli and the modulatory effect that these differences in perceived taste intensity have on swallowing behaviors. Participants were 80 healthy women, stratified by age group (<40; >60) and genetic taste status (supertasters; nontasters). Perceived taste intensity and chemesthetic properties (fizziness; burning-stinging) were rated for 7 tastant solutions (each prepared with and without barium) using the general Labeled Magnitude Scale. Tongue-palate pressures and submental surface electromyography (sEMG) were simultaneously measured during swallowing of these same randomized liquids. Path analysis differentiated the effects of stimulus, genetic taste status, age, barium condition, taste intensity, and an effortful saliva swallow strength covariate on swallowing. Barium stimuli were rated as having reduced taste intensity compared with nonbarium stimuli. Barium also dampened fizziness but did not influence burning-stinging sensation. The amplitudes of tongue-palate pressure or submental sEMG did not differ when swallowing barium versus nonbarium stimuli. Despite impacting taste intensity, the addition of barium to liquid stimuli does not appear to alter behavioral parameters of swallowing. Barium solutions can be considered to elicit behaviors that are similar to those used with nonbarium liquids outside the assessment situation.

  8. Radium and barium in the Amazon River system

    SciTech Connect

    Moore, W.S.; Edmond, J.M.

    1984-03-20

    Data for /sup 226/Ra and /sup 228/Ra in the Amazon River system show that the activity of each radium isotope is strongly correlated with barium concentrations. Two trends are apparent, one for rivers which drain shield areas and another for all other rivers. These data suggest that there has been extensive fractionation of U, Th, and Ba during weathering in the Amazon basin. The /sup 226/Ra data fit a flux model for the major ions indicating that /sup 226/Ra behaves conservatively along the main channel of the Amazon River.

  9. Strain engineered barium strontium titanate for tunable thin film resonators

    SciTech Connect

    Khassaf, H.; Khakpash, N.; Sun, F.; Sbrockey, N. M.; Tompa, G. S.; Kalkur, T. S.; Alpay, S. P.

    2014-05-19

    Piezoelectric properties of epitaxial (001) barium strontium titanate (BST) films are computed as functions of composition, misfit strain, and temperature using a non-linear thermodynamic model. Results show that through adjusting in-plane strains, a highly adaptive rhombohedral ferroelectric phase can be stabilized at room temperature with outstanding piezoelectric response exceeding those of lead based piezoceramics. Furthermore, by adjusting the composition and the in-plane misfit, an electrically tunable piezoelectric response can be obtained in the paraelectric state. These findings indicate that strain engineered BST films can be utilized in the development of electrically tunable and switchable surface and bulk acoustic wave resonators.

  10. Dielectric behavior of barium modified strontium bismuth titanate ceramic

    NASA Astrophysics Data System (ADS)

    Nayak, P.; Badapanda, T.; Anwar, S.; Panigrahi, S.

    2014-04-01

    Barium Modified Strontium Bismuth Titanate(SBT) ceramic with general formula Sr1-xBaxBi4Ti4O15 is prepared by solid state reaction route. The structural analysis of the ceramics was done by X-ray diffraction technique. The X-ray patterns show that all the compositions are of single phase with orthorhombic structure. The temperature dependent dielectric behavior shows that the transition temperature decreases with Ba content but the maximum dielectric constant increases. The decreases of the transition with increase in Ba2+ ion, may be due to the decrease of orthorhombicity by the incorporation of Ba2+ ion in SBT lattice.

  11. The barium ion jet experiments of the Porcupine project

    NASA Astrophysics Data System (ADS)

    Haerendel, G.

    1980-06-01

    The injection of a barium plasma from a sounding rocket by the shaped charge technique offers several possibilities that cannot be achieved by conventional releases. This is due to high initial velocities of the atoms of up to 14 km/sec. Most of the the applications are related to the great heights that the ions can reach, but some depend directly on the initial momentum. Typical applications are: tracing at high altitudes, modifications, and alternate Ionization processes. Project Porcupine contributions in this field are summarized.

  12. Enhanced flexoelectricity through residual ferroelectricity in barium strontium titanate

    SciTech Connect

    Garten, Lauren M. Trolier-McKinstry, Susan

    2015-03-07

    Residual ferroelectricity is observed in barium strontium titanate ceramics over 30 °C above the global phase transition temperature, in the same temperature range in which anomalously large flexoelectric coefficients are reported. The application of a strain gradient leads to strain gradient-induced poling or flexoelectric poling. This was observed by the development of a remanent polarization in flexoelectric measurements, an induced d{sub 33} piezoelectric response even after the strain gradient was removed, and the production of an internal bias of 9 kV m{sup −1}. It is concluded that residual ferroelectric response considerably enhances the observed flexoelectric response.

  13. On the nature of striae in strontium barium niobate

    NASA Astrophysics Data System (ADS)

    Monchamp, R. R.; Mihalik, G. B.; Franks, L. A.

    1994-08-01

    Strontium barium niobate crystals were grown by the Czochralski technique. These crystals were 15-20 mm in diameter and 25 to 75 mm long. Two types of striae, designated as coarse and fine, were characterized. The coarse striae are optically dense and are spaced by 100 to 500 microns apart; the fine striae are optically less dense and spaced 5-50 microns apart. The origins of the striae are attributed to thermal fluctuations in the melt related to the control system and to rotation of the growing crystal in non-isothermal radial gradients. Analysis of the crystals indicated that the coarse striae may contain increased concentrations of sodium.

  14. Co,Ti,Mn-precipitated barium hexaferrite powders

    SciTech Connect

    Michalikova, M.; Gruskova, A.; Vicen, R.; Lipka, J.; Slama, J.

    1994-03-01

    Barium ferrites substituted Co, Ti, Mn, produced by the citrate method have been studied. The substitution x in BaCo{sub x}Ti{sub x}Mn{sub y}Fe{sub 12{minus}2x{minus}y}O{sub 19} has been varied from 0.2--2.0 i./f.u. and the substitution of Mn y = 0.1 i./f.u.. Magnetic parameters were measured by the vibration magnetometer. The mechanism of hexagonal structure formation has been checked by Moessbauer spectroscopy.

  15. Evidence against barium in the mushroom Trogia venenata as a cause of sudden unexpected deaths in Yunnan, China.

    PubMed

    Zhang, Ying; Li, Yanchun; Wu, Gang; Feng, Bang; Yoell, Shanze; Yu, Zefen; Zhang, Keqin; Xu, Jianping

    2012-12-01

    This study examined barium concentrations in the mushroom Trogia venenata, the leading culprit for sudden unexpected deaths in Yunnan, southwest China. We found that barium concentrations in T. venenata from Yunnan were low and comparable to other foods, inconsistent with barium concentrations in this mushroom as a significant contributor to these deaths.

  16. Evaluation of gastrointestinal tract transit times using barium-impregnated polyethylene spheres and barium sulfate suspension in a domestic pigeon (Columba livia) model.

    PubMed

    Bloch, Rebecca A; Cronin, Kimberly; Hoover, John P; Pechman, Robert D; Payton, Mark E

    2010-03-01

    Barium impregnated polyethylene spheres (BIPS) are used in small animal medicine as an alternative to barium sulfate for radiographic studies of the gastrointestinal tract. To determine the usefulness of BIPS as an alternative to barium suspension in measuring gastrointestinal (GI) transit time for avian species, ventrodorsal radiographs were used to follow the passage of BIPS and 30% barium sulfate suspension through the GI tracts of domestic pigeons (Columba livia). Gastrointestinal transit times of thirty 1.5-mm BIPS administered in moistened gelatin capsules and 30% barium sulfate suspension gavaged into the crop were compared in 6 pigeons. Although the barium suspension passed out of the GI tract of all pigeons within 24 hours, the 1.5-mm BIPS remained in the ventriculus for 368.0 +/- 176.8 hours and did not clear the GI tract for 424.0 +/- 204.6 hours. Although the times for passage of BIPS and 30% barium sulfate suspension from the crop into the ventriculus were not significantly different (P = .14), the times for passage of BIPS from the ventriculus into the large intestine-cloaca and for clearance from the GI tract of the pigeons were significantly longer (P < .001) than for the 30% barium sulfate suspension. From the results of this study, we conclude that BIPS are not useful for radiographically evaluating GI transit times in pigeons and are unlikely to be useful in other avian species that have a muscular ventriculus. BIPS may or may not be useful for evaluating GI transit times in species that lack a muscular ventriculus.

  17. Centrifugal Jet Spinning for Highly Efficient and Large-scale Fabrication of Barium Titanate Nanofibers

    PubMed Central

    Ren, Liyun; Kotha, Shiva P.

    2014-01-01

    The centrifugal jet spinning (CJS) method has been developed to enable large-scale synthesis of barium titanate nanofibers. Barium titanate nanofibers with fiber diameters down to 50 nm and grain sizes around 25 nm were prepared with CJS by spinning a sol-gel solution of barium titanate and poly(vinylpyrrolidone) with subsequent heat treatment at 850 °C. XRD and FTIR analysis demonstrated high purity and tetragonal perovskite structured barium titanate nanofibers. SEM and TEM images confirm the continuous high aspect ratio structure of barium titanate nanofibers after heat treatment. It is demonstrated that the CJS technique offers a highly efficient method for large-scale fabrication of ceramic nanofibers at production rates of up to 0.3 gram/minute. PMID:24563566

  18. Acute phosphate nephropathy.

    PubMed

    Monfared, Ali; Habibzadeh, Seyed Mahmoud; Mesbah, Seyed Alireza

    2014-05-01

    We present acute phosphate nephropathy in a 28-year-old man, which was developed after a car accident due to rhabdomyolysis. Treatment of acute kidney injury was done with administration of sodium bicarbonate.

  19. Phosphate Mines, Jordan

    NASA Image and Video Library

    2008-04-21

    Jordan leading industry and export commodities are phosphate and potash, ranked in the top three in the world. These are used to make fertilizer. This image was acquired by NASA Terra satellite on September 17, 2005.

  20. Metal-phosphate binders

    DOEpatents

    Howe, Beth Ann [Lewistown, IL; Chaps-Cabrera, Jesus Guadalupe [Coahuila, MX

    2009-05-12

    A metal-phosphate binder is provided. The binder may include an aqueous phosphoric acid solution, a metal-cation donor including a metal other than aluminum, an aluminum-cation donor, and a non-carbohydrate electron donor.

  1. Phosphate control in dialysis

    PubMed Central

    Cupisti, Adamasco; Gallieni, Maurizio; Rizzo, Maria Antonietta; Caria, Stefania; Meola, Mario; Bolasco, Piergiorgio

    2013-01-01

    Prevention and correction of hyperphosphatemia is a major goal of chronic kidney disease–mineral and bone disorder (CKD–MBD) management, achievable through avoidance of a positive phosphate balance. To this aim, optimal dialysis removal, careful use of phosphate binders, and dietary phosphate control are needed to optimize the control of phosphate balance in well-nourished patients on a standard three-times-a-week hemodialysis schedule. Using a mixed diffusive–convective hemodialysis tecniques, and increasing the number and/or the duration of dialysis tecniques are all measures able to enhance phosphorus (P) mass removal through dialysis. However, dialytic removal does not equal the high P intake linked to the high dietary protein requirement of dialysis patients; hence, the use of intestinal P binders is mandatory to reduce P net intestinal absorption. Unfortunately, even a large dose of P binders is able to bind approximately 200–300 mg of P on a daily basis, so it is evident that their efficacy is limited in the case of an uncontrolled dietary P load. Hence, limitation of dietary P intake is needed to reach the goal of neutral phosphate balance in dialysis, coupled to an adequate protein intake. To this aim, patients should be informed and educated to avoid foods that are naturally rich in phosphate and also processed food with P-containing preservatives. In addition, patients should preferentially choose food with a low P-to-protein ratio. For example, patients could choose egg white or protein from a vegetable source. Finally, boiling should be the preferred cooking procedure, because it induces food demineralization, including phosphate loss. The integrated approach outlined in this article should be actively adapted as a therapeutic alliance by clinicians, dieticians, and patients for an effective control of phosphate balance in dialysis patients. PMID:24133374

  2. Phosphate control in dialysis.

    PubMed

    Cupisti, Adamasco; Gallieni, Maurizio; Rizzo, Maria Antonietta; Caria, Stefania; Meola, Mario; Bolasco, Piergiorgio

    2013-10-04

    Prevention and correction of hyperphosphatemia is a major goal of chronic kidney disease-mineral and bone disorder (CKD-MBD) management, achievable through avoidance of a positive phosphate balance. To this aim, optimal dialysis removal, careful use of phosphate binders, and dietary phosphate control are needed to optimize the control of phosphate balance in well-nourished patients on a standard three-times-a-week hemodialysis schedule. Using a mixed diffusive-convective hemodialysis tecniques, and increasing the number and/or the duration of dialysis tecniques are all measures able to enhance phosphorus (P) mass removal through dialysis. However, dialytic removal does not equal the high P intake linked to the high dietary protein requirement of dialysis patients; hence, the use of intestinal P binders is mandatory to reduce P net intestinal absorption. Unfortunately, even a large dose of P binders is able to bind approximately 200-300 mg of P on a daily basis, so it is evident that their efficacy is limited in the case of an uncontrolled dietary P load. Hence, limitation of dietary P intake is needed to reach the goal of neutral phosphate balance in dialysis, coupled to an adequate protein intake. To this aim, patients should be informed and educated to avoid foods that are naturally rich in phosphate and also processed food with P-containing preservatives. In addition, patients should preferentially choose food with a low P-to-protein ratio. For example, patients could choose egg white or protein from a vegetable source. Finally, boiling should be the preferred cooking procedure, because it induces food demineralization, including phosphate loss. The integrated approach outlined in this article should be actively adapted as a therapeutic alliance by clinicians, dieticians, and patients for an effective control of phosphate balance in dialysis patients.

  3. Tungsten and Barium Transport in the Internal Plasma of Hollow Cathodes

    NASA Technical Reports Server (NTRS)

    Polk, James E.; Mikellides, Ioannis G.; Katz, Ira; Capece, Angela M.

    2008-01-01

    The effect of tungsten erosion, transport and redeposition on the operation of dispenser hollow cathodes was investigated in detailed examinations of the discharge cathode inserts from an 8200 hour and a 30,352 hour ion engine wear test. Erosion and subsequent re-deposition of tungsten in the electron emission zone at the downstream end of the insert reduces the porosity of the tungsten matrix, preventing the flow of barium from the interior. This inhibits the interfacial reactions of the barium-calcium-aluminate impregnant with the tungsten in the pores. A numerical model of barium transport in the internal xenon discharge plasma shows that the barium required to reduce the work function in the emission zone can be supplied from upstream through the gas phase. Barium that flows out of the pores of the tungsten insert is rapidly ionized in the xenon discharge and pushedback to the emitter surface by the electric field and drag from the xenon ion flow. Thisbarium ion flux is sufficient to maintain a barium surface coverage at the downstream endgreater than 0.6, even if local barium production at that point is inhibited by tungsten deposits. The model also shows that the neutral barium pressure exceeds the equilibrium vapor pressure of the impregnant decomposition reaction over much of the insert length,so the reactions are suppressed. Only a small region upstream of the zone blocked by tungsten deposits is active and supplies the required barium. These results indicate that hollowcathode failure models based on barium depletion rates in vacuum dispenser cathodes are very conservative.

  4. Endotrophic Calcium, Strontium, and Barium Spores of Bacillus megaterium and Bacillus cereus1

    PubMed Central

    Foerster, Harold F.; Foster, J. W.

    1966-01-01

    Foerster, Harold F. (The University of Texas, Austin), and J. W. Foster. Endotrophic calcium, strontium, and barium spores of Bacillus megaterium and Bacillus cereus. J. Bacteriol. 91:1333–1345. 1966.—Spores were produced by washed vegetative cells suspended in deionized water supplemented with CaCl2, SrCl2, or BaCl2. Normal, refractile spores were produced in each case; a portion of the barium spores lost refractility and darkened. Thin-section electron micrographs revealed no apparent anatomical differences among the three types of spores. Analyses revealed that the different spore types were enriched specifically in the metal to which they were exposed during sporogenesis. The calcium content of the strontium and the barium spores was very small. From binary equimolar mixtures of the metal salts, endotrophic spores accumulated both metals to nearly the same extent. Viability of the barium spores was considerably less than that of the other two types. Strontium and barium spores were heat-resistant; however, calcium was essential for maximal heat resistance. Significant differences existed in the rates of germination; calcium spores germinated fastest, strontium spores were slower, and barium spores were slowest. Calcium-barium and calcium-strontium spores germinated readily. Endotrophic calcium and strontium spores germinated without the prior heat activation essential for growth spores. Chemical germination of the different metal-type spores with n-dodecylamine took place at the same relative rates as physiological germination. Heat-induced release of dipicolinic acid occurred much faster with barium and strontium spores than with calcium spores. The washed “coat fraction” from disrupted spores contained little of the spore calcium but most of the spore barium. The metal in this fraction was released by dilute acid. The demineralized coats reabsorbed calcium and barium at neutral pH. Images PMID:4956334

  5. Effects of chemesthetic stimuli mixtures with barium on swallowing apnea duration.

    PubMed

    Todd, J Tee; Butler, Susan G; Plonk, Drew P; Grace-Martin, Karen; Pelletier, Cathy A

    2012-10-01

    This study tested the hypotheses that swallowing apnea duration (SAD) will increase given barium versus water, chemesthetic stimuli (i.e., water < ethanol, acid, and carbonation) mixed with barium, age (older > younger), and genetic taste differences (supertasters > nontasters). Prospective group design. University Medical Center. Eighty healthy women were identified as nontasters and supertasters, equally comprising two age groups: 18 to 35 years and 60+ years. The KayPentax Swallowing Signals Lab was used to acquire SAD via nasal cannula during individually randomized swallows of 5 mL barium, 2.7% w/v citric acid with barium, carbonation with barium, and 50:50 diluted ethanol with barium. Data were analyzed using path analysis, with the mediator of chemesthetic perception, adjusted for repeated measures. Significant main effects of age (P = .012) and chemesthetic stimuli (P = .014) were found, as well as a significant interaction between chemesthetic stimuli and age (P = .028). Older women had a significantly longer SAD than younger women. Post hoc analyses revealed that barium mixed with ethanol elicited a significantly longer SAD than other bolus conditions, regardless of age group. There were no significant differences in SAD between barium and water conditions, and no significant effect of chemesthetic perception (P > .05). Ethanol added to barium elicited longer SAD compared to plain barium, but not the other chemesthetic conditions. Older women had a longer SAD than younger women in all conditions. These findings may influence design of future studies examining effects of various stimuli on SAD. Copyright © 2012 The American Laryngological, Rhinological, and Otological Society, Inc.

  6. Tungsten and Barium Transport in the Internal Plasma of Hollow Cathodes

    NASA Technical Reports Server (NTRS)

    Polk, James E.; Mikellides, Ioannis G.; Katz, Ira; Capece, Angela M.

    2008-01-01

    The effect of tungsten erosion, transport and redeposition on the operation of dispenser hollow cathodes was investigated in detailed examinations of the discharge cathode inserts from an 8200 hour and a 30,352 hour ion engine wear test. Erosion and subsequent re-deposition of tungsten in the electron emission zone at the downstream end of the insert reduces the porosity of the tungsten matrix, preventing the flow of barium from the interior. This inhibits the interfacial reactions of the barium-calcium-aluminate impregnant with the tungsten in the pores. A numerical model of barium transport in the internal xenon discharge plasma shows that the barium required to reduce the work function in the emission zone can be supplied from upstream through the gas phase. Barium that flows out of the pores of the tungsten insert is rapidly ionized in the xenon discharge and pushedback to the emitter surface by the electric field and drag from the xenon ion flow. Thisbarium ion flux is sufficient to maintain a barium surface coverage at the downstream endgreater than 0.6, even if local barium production at that point is inhibited by tungsten deposits. The model also shows that the neutral barium pressure exceeds the equilibrium vapor pressure of the impregnant decomposition reaction over much of the insert length,so the reactions are suppressed. Only a small region upstream of the zone blocked by tungsten deposits is active and supplies the required barium. These results indicate that hollowcathode failure models based on barium depletion rates in vacuum dispenser cathodes are very conservative.

  7. Multi-colony calibrations of coral Ba/Ca with a contemporaneous in situ seawater barium record

    NASA Astrophysics Data System (ADS)

    LaVigne, Michèle; Grottoli, Andréa G.; Palardy, James E.; Sherrell, Robert M.

    2016-04-01

    The coral skeleton barium to calcium ratio (Ba/Cacoral), a proxy for seawater barium concentrations (BaSW), has been interpreted as a tracer of upwelling based on the characteristic "nutrient like" depth profile of BaSW. However, in some tropical regions, such as the Gulf of Panamá, substantial influence of terrestrial runoff inputs and differences between the vertical distribution of BaSW and that of the major nutrients (nitrate and phosphate) in the upper water column can complicate the interpretation of Ba/Cacoral as an upwelled nutrient proxy. In the Gulf of Panamá, contemporaneous Ba/Cacoral records from multiple colonies of Porites lobata, Pavona gigantea, and Pavona clavus corals record a nearly twofold change in surface water BaSW as a 20-70% increase in skeletal Ba/Ca with excellent correlation among Ba/Ca records from co-located colonies (r = 0.86-0.99). These results provide, for the first time, an absolute calibration of the coral Ba proxy with a contemporaneous BaSW record. Compiling the Ba/Cacoral records from three co-located colonies of each species into taxon-specific composite regressions reveals strong statistically significant correlations with the BaSW time-series record (p < 0.001). Differences among taxa in regression slope, y-intercept, and average distribution coefficient, as well as a demonstration of the application of the P. clavus calibration to a previously published Ba/Cacoral record, emphasize the necessity of using taxon-specific calibrations to reconstruct changes in BaSW with accuracy. These results support the application of Ba/Cacoral to reconstruct past changes in absolute BaSW concentrations, adding an important tool to the collection of geochemical proxies for reconstructing surface ocean biogeochemical processes in the past.

  8. Structural and optical study of tellurite-barium glasses

    NASA Astrophysics Data System (ADS)

    Grelowska, I.; Reben, M.; Burtan, B.; Sitarz, M.; Cisowski, J.; Yousef, El Sayed; Knapik, A.; Dudek, M.

    2016-12-01

    The goal of this work was to determine the effect of barium oxide on the structural, thermal and optical properties of the TeO2-BaO-Na2O (TBN) and TeO2-BaO-WO3 (TBW) glass systems. Raman spectra allow relating the glass structure and vibration properties (i.e. vibrational frequencies and Raman intensities) with the glass composition. Raman spectra show the presence of TeO4 and TeO3+1/TeO3 units that conform with the glass matrix. Differential thermal analysis DTA, XRD measurements have been considered in term of BaO addition. The spectral dependence of ellipsometric angles of the tellurite-barium glass has been studied. The optical measurements were conducted on Woollam M2000 spectroscopic ellipsometer in spectral range of 190-1700 nm. The reflectance and transmittance measurements have been done on spectrophotometer Perkin Elmer, Lambda 900 in the range of 200-2500 nm (UV-VIS-NIR). From the transmittance spectrum, the energy gap was determined.

  9. Plasma waves associated with the first AMPTE magnetotail barium release

    NASA Technical Reports Server (NTRS)

    Gurnett, D. A.; Anderson, R. R.; Bernhardt, P. A.; Luehr, H.; Haerendel, G.

    1986-01-01

    Plasma waves observed during the March 21, 1985, AMPTE magnetotail barium release are described. Electron plasma oscillations provided local measurements of the plasma density during both the expansion and decay phases. Immediately after the explosion, the electron density reached a peak of about 400,000/cu cm, and then started decreasing approximately as t to the -2.4 as the cloud expanded. About 6 minutes after the explosion, the electron density suddenly began to increase, reached a secondary peak of about 240/cu cm, and then slowly decayed down to the preevent level over a period of about 15 minutes. The density increase is believed to be caused by the collapse of the ion cloud into the diamagnetic cavity created by the initial expansion. The plasma wave intensities observed during the entire event were quite low. In the diamagnetic cavity, electrostatic emissions were observed near the barium ion plasma frequency, and in another band at lower frequencies. A broadband burst of electrostatic noise was also observed at the boundary of the diamagnetic cavity. Except for electron plasma oscillations, no significant wave activity was observed outside of the diamagnetic cavity.

  10. Monte Carlo calculations of the microstructure of barium ferrite dispersions

    NASA Astrophysics Data System (ADS)

    Walmsley, N. S.; Coverdale, G. N.; Chantrell, R. W.; Parker, D. A.; Bissell, P. R.

    1998-07-01

    A Monte Carlo (MC) model has been developed to investigate the influences of the volume packing fraction and applied field on the equilibrium microstructure of a dispersion of barium ferrite particles. We accounted for magnetostatic interaction effects by using a surface charge model which allows the calculation of the energy term required for the Metropolis-type MC algorithm. In addition to single particle moves, the model employs a clustering algorithm, based on particle proximity, in order to take into account the cooperative behaviour of the particles bound by magnetostatic energy. The stacks which are thought to be characteristic of barium ferrite systems are an example of this type of binding. Our study provides strong evidence, in agreement with experiment, for the formation of stacks both in the zero field and in the applied field equilibrium configurations. The simulation also predicts, by considering the effects of the packing density, that the dispersion properties are strongly affected by the mobility of these stacks. The equilibrium particle configurations have been investigated using a correlation function and visualized by computer graphics. The magnetic behaviour has been investigated by calculation of the magnetization curve.

  11. Barium titanate core – gold shell nanoparticles for hyperthermia treatments

    PubMed Central

    FarrokhTakin, Elmira; Ciofani, Gianni; Puleo, Gian Luigi; de Vito, Giuseppe; Filippeschi, Carlo; Mazzolai, Barbara; Piazza, Vincenzo; Mattoli, Virgilio

    2013-01-01

    The development of new tools and devices to aid in treating cancer is a hot topic in biomedical research. The practice of using heat (hyperthermia) to treat cancerous lesions has a long history dating back to ancient Greece. With deeper knowledge of the factors that cause cancer and the transmissive window of cells and tissues in the near-infrared region of the electromagnetic spectrum, hyperthermia applications have been able to incorporate the use of lasers. Photothermal therapy has been introduced as a selective and noninvasive treatment for cancer, in which exogenous photothermal agents are exploited to achieve the selective destruction of cancer cells. In this manuscript, we propose applications of barium titanate core–gold shell nanoparticles for hyperthermia treatment against cancer cells. We explored the effect of increasing concentrations of these nanoshells (0–100 μg/mL) on human neuroblastoma SH-SY5Y cells, testing the internalization and intrinsic toxicity and validating the hyperthermic functionality of the particles through near infrared (NIR) laser-induced thermoablation experiments. No significant changes were observed in cell viability up to nanoparticle concentrations of 50 μg/mL. Experiments upon stimulation with an NIR laser revealed the ability of the nanoshells to destroy human neuroblastoma cells. On the basis of these findings, barium titanate core–gold shell nanoparticles resulted in being suitable for hyperthermia treatment, and our results represent a promising first step for subsequent investigations on their applicability in clinical practice. PMID:23847415

  12. Results of magnetospheric barium ion cloud experiment of 1971

    NASA Technical Reports Server (NTRS)

    Adamson, D.; Fricke, C. L.; Long, S. A. T.

    1975-01-01

    The barium ion cloud experiment involved the release of about 2 kg of barium at an altitude of 31 482 km, a latitude of 6.926 N., and a longitude of 74.395 W. Significant erosion of plasma from the main ion core occurred during the initial phase of the ion cloud expansion. From the motion of the outermost striational filaments, the electric field components were determined to be 0.19 mV/m in the westerly direction and 0.68 mV/m in the inward direction. The differences between these components and those measured from balloons flown in the proximity of the extremity of the field line through the release point implied the existence of potential gradients along the magnetic field lines. The deceleration of the main core was greater than theoretically predicted. This was attributed to the formation of a polarization wake, resulting in an increase of the area of interaction and resistive dissipation at ionospheric levels. The actual orientation of the magnetic field line through the release point differed by about 10.5 deg from that predicted by magnetic field models that did not include the effect of ring current.

  13. Brillouin function characteristics for La-Co substituted barium hexaferrites

    NASA Astrophysics Data System (ADS)

    Wu, Chuanjian; Yu, Zhong; Yang, Yan; Sun, Ke; Guo, Rongdi; Jiang, Xiaona; Lan, Zhongwen

    2015-09-01

    La-Co substituted barium hexaferrites with the chemical formula of Ba1-xLaxFe12-xCoxO19 (x = 0.0, 0.1, 0.3, and 0.5), prepared by a conventional ceramic method, were systematically investigated by Raman spectra, X-ray photoelectron spectroscopy, Rietveld refinement of X-ray diffraction patterns, and vibrating sample magnetometer. The result manifests that all the compounds are crystallized in magnetoplumbite hexagonal structure. Trivalent cobalt ions prevailingly occupy the 2a, 4f1, and 12k sites. According to Néel model of collinear-spin ferrimagnetism, the molecular-field coefficients ωbf2, ωkf1, ωaf1, ωkf2, and ωbk of La-Co substituted barium hexaferrites have been calculated using the nonlinear fitting method, and the magnetic moment of five sublattices (2a, 2b, 4f1, 4f2, and 12k) versus temperature T has been also investigated. The fitting results are coincided well with the experimental data. Moreover, with the increase of La-Co substitution amount x, the molecular-field coefficients ωbf2 and ωaf1 decrease constantly, while the molecular-field coefficients ωkf1, ωkf2, and ωbk show a slight change.

  14. Barium titanate core--gold shell nanoparticles for hyperthermia treatments.

    PubMed

    FarrokhTakin, Elmira; Ciofani, Gianni; Puleo, Gian Luigi; de Vito, Giuseppe; Filippeschi, Carlo; Mazzolai, Barbara; Piazza, Vincenzo; Mattoli, Virgilio

    2013-01-01

    The development of new tools and devices to aid in treating cancer is a hot topic in biomedical research. The practice of using heat (hyperthermia) to treat cancerous lesions has a long history dating back to ancient Greece. With deeper knowledge of the factors that cause cancer and the transmissive window of cells and tissues in the near-infrared region of the electromagnetic spectrum, hyperthermia applications have been able to incorporate the use of lasers. Photothermal therapy has been introduced as a selective and noninvasive treatment for cancer, in which exogenous photothermal agents are exploited to achieve the selective destruction of cancer cells. In this manuscript, we propose applications of barium titanate core-gold shell nanoparticles for hyperthermia treatment against cancer cells. We explored the effect of increasing concentrations of these nanoshells (0-100 μg/mL) on human neuroblastoma SH-SY5Y cells, testing the internalization and intrinsic toxicity and validating the hyperthermic functionality of the particles through near infrared (NIR) laser-induced thermoablation experiments. No significant changes were observed in cell viability up to nanoparticle concentrations of 50 μg/mL. Experiments upon stimulation with an NIR laser revealed the ability of the nanoshells to destroy human neuroblastoma cells. On the basis of these findings, barium titanate core-gold shell nanoparticles resulted in being suitable for hyperthermia treatment, and our results represent a promising first step for subsequent investigations on their applicability in clinical practice.

  15. Synthesis of Barium Titanate Using Deep Eutectic Solvents.

    PubMed

    Boston, Rebecca; Foeller, Philip Y; Sinclair, Derek C; Reaney, Ian M

    2017-01-03

    Novel synthetic routes to prepare functional oxides at lower temperatures are an increasingly important area of research. Many of these synthetic routes, however, use water as the solvent and rely on dissolution of the precursors, precluding their use with, for example, titanates. Here we present a low-cost solvent system as a means to rapidly create phase-pure ferroelectric barium titanate using a choline chloride-malonic acid deep eutectic solvent. This solvent is compatible with alkoxide precursors and allows for the rapid synthesis of nanoscale barium titanate powders at 950 °C. The phase and morphology were determined, along with investigation of the synthetic pathway, with the reaction proceeding via BaCl2 and TiO2 intermediates. The powders were also used to create sintered ceramics, which exhibit a permittivity maximum corresponding to a tetragonal-cubic transition at 112 °C, as opposed to the more conventional temperature of ∼120 °C. The lower-than-expected value for the ferro- to para-electric phase transition is likely due to undetectable levels of contaminants.

  16. Prospects for the ORNL/TAMU Barium Fluoride Array

    NASA Astrophysics Data System (ADS)

    Townsend, Austin; McIntosh, Alan; Youngs, Mike; Mosby, Shea; Varner, Robert

    2016-09-01

    Understanding the symmetry energy in the nuclear equation of state is essential to understanding properties such as the structure of a neutron star or its gravitational collapse, leading to supernovae. It has been suggested that to better constrain the symmetry energy one can use the bremmstrahlung gamma rays emitted from the hot, dense nuclear matter in the early stages of heavy ion collisions. These gamma rays have the potential to provide a cleaner probe than the more traditional hadronic probes. To measure these bremmstrahlung photons, barium fluoride scintillation crystals were chosen for their ability to detect photons across a large energy range and for their inherent pulse shape discrimination properties. This summer, the detectors of the TAMU/ORNL barium fluoride array were tested in preparation for such an experiment. Signals from each detector were recorded individually for cosmic rays and radioactive source events. The full waveforms were digitized with flash ADCs. A selected set of detectors was assembled and tested with beam from the K500 cyclotron. With this in-beam data, waveform integration parameters may be optimized. Results from the testing of these detectors with flash digitizers will be presented. Department of Energy, National Science Foundation, Cyclotron Institute.

  17. Liquid-Phase Processing of Barium Titanate Thin Films

    NASA Astrophysics Data System (ADS)

    Harris, David Thomas

    Processing of thin films introduces strict limits on the thermal budget due to substrate stability and thermal expansion mismatch stresses. Barium titanate serves as a model system for the difficulty in producing high quality thin films because of sensitivity to stress, scale, and crystal quality. Thermal budget restriction leads to reduced crystal quality, density, and grain growth, depressing ferroelectric and nonlinear dielectric properties. Processing of barium titanate is typically performed at temperatures hundreds of degrees above compatibility with metalized substrates. In particular integration with silicon and other low thermal expansion substrates is desirable for reductions in costs and wider availability of technologies. In bulk metal and ceramic systems, sintering behavior has been encouraged by the addition of a liquid forming second phase, improving kinetics and promoting densification and grain growth at lower temperatures. This approach is also widespread in the multilayer ceramic capacitor industry. However only limited exploration of flux processing with refractory thin films has been performed despite offering improved dielectric properties for barium titanate films at lower temperatures. This dissertation explores physical vapor deposition of barium titanate thin films with addition of liquid forming fluxes. Flux systems studied include BaO-B2O3, Bi2O3-BaB2O 4, BaO-V2O5, CuO-BaO-B2O3, and BaO-B2O3 modified by Al, Si, V, and Li. Additions of BaO-B2O3 leads to densification and an increase in average grain size from 50 nm to over 300 nm after annealing at 900 °C. The ability to tune permittivity of the material improved from 20% to 70%. Development of high quality films enables engineering of ferroelectric phase stability using residual thermal expansion mismatch in polycrystalline films. The observed shifts to TC match thermodynamic calculations, expected strain from the thermal expansion coefficients, as well as x-ray diffract measurements

  18. Barium zirconate-titanate/barium calcium-titanate ceramics via sol-gel process: novel high-energy-density capacitors

    NASA Astrophysics Data System (ADS)

    Sreenivas Puli, Venkata; Kumar, Ashok; Chrisey, Douglas B.; Tomozawa, M.; Scott, J. F.; Katiyar, Ram S.

    2011-10-01

    Lead-free barium zirconate-titanate/barium calcium-titanate, [(BaZr0.2Ti0.80)O3]1-x-[(Ba0.70Ca0.30)TiO3]x (x = 0.10, 0.15, 0.20) (BZT-BCT) ceramics with high dielectric constant, low dielectric loss and moderate electric breakdown field were prepared by the sol-gel synthesis technique. X-ray diffraction patterns revealed tetragonal crystal structure and this was further confirmed by Raman spectra. Well-behaved ferroelectric hysteresis loops and moderate polarizations (spontaneous polarization, Ps ~ 3-6 µC cm-2) were obtained in these BZT-BCT ceramics. Frequency-dependent dielectric spectra confirmed that ferroelectric diffuse phase transition (DPT) exists near room temperature. Scanning electron microscope images revealed monolithic grain growth in samples sintered at 1280 °C. 1000/ɛ versus (T) plots revealed ferroelectric DPT behaviour with estimated γ values of ~1.52, 1.51 and 1.88, respectively, for the studied BZT-BCT compositions. All three compositions showed packing-limited breakdown fields of ~47-73 kV cm-1 with an energy density of 0.05-0.6 J cm-3 for thick ceramics (>1 mm). Therefore these compositions might be useful in Y5V-type capacitor applications.

  19. Sodium phosphate-derived calcium phosphate cements

    SciTech Connect

    Sugama, T.; Carciello, N.R. )

    1995-01-01

    Calcium phosphate cements (CPC) were synthesized by the acid-base reaction between sodium phosphate, NaH[sub 2]PO[sub 4] or -(-NaPO[sub 3]-)-[sub n], as the acid solution, and calcium aluminate cements (CAC) as the base reactant at 25 C. The extent of reactivity of -(-NaPO[sub 3]-)-[sub n] with CAC was much higher than that of NaH[sub 2]PO[sub 4], thereby resulting in a compressive strength of > 20 MPa. Sodium calcium orthophosphate (SCOP) salts as amorphous reaction products were responsible for the development of this strength. When this CPC specimen as exposed in an autoclave, in-situ amorphous [r arrow] crystal conversions, such as SCOP [r arrow] hydroxyapatite (HOAp), and Al[sub 2]O[sub 3] [center dot] xH[sub 2]O [r arrow] [gamma]-AlOOH, occurred at [approx] 100 C, while the rate of reaction of the residual CAC with the phosphate reactant was increasingly accelerated by hydrothermal catalysis. Based upon this information, the authors prepared lightweight CPC specimens by hydrothermally treating a low-density cement slurry (1.28 g/cc) consisting of CAC powder, -(-NaPO[sub 3]-)-[sub n] solution, and mullite-hollow microspheres. The characteristics of the autoclaved lightweight specimens were a compressive strength of > 9.0 MPa, water permeability of [approx] 5.0 [times] 10[sup [minus]3] milli darcy, and a low rate of alkali carbonation. The reasons for such a low carbonation rate reflected the presence of a minimum amount of residual CAC, in conjunction with the presence of HOAp and [gamma]-AlOOH phases that are unsusceptible to wet carbonation.

  20. [beta]-BaV[sub 2](P[sub 2]O[sub 7])[sub 2]: A new polymorph of barium vanadium (III) pyrophosphate characterized by intersecting tunnels

    SciTech Connect

    Hwu, Shiou-Jyh; Carroll, R.I.; Serra, D.L. )

    1994-06-01

    Investigation into the synthesis of reduced vanadium phosphate has led to the formation of a new form of the barium vanadium (III) pyrophosphate compound [beta]-BaV[sub 2](P[sub 2]O[sub 7])[sub 2]. It is a polymorph of the previously known BaV[sub 2](P[sub 2]O[sub 7])[sub 2], which is now labeled as the [alpha]-phase. The title compound crystallizes in the P-1 (No. 2) space group with a = 6.269 (1) [angstrom], b = 7.864 (3) [angstrom], c = 6.1592 (9) [angstrom], [alpha] = 101.34 (2)[degree], [beta] = 105.84 (1)[degree], and [gamma] = 96.51 (2)[degree]. The structure consists of corner-shared VO[sub 6] octahedra and PO[sub 4] tetrahedra that are connected in V-O-P-O-V and V-O-P-O-P-O-V bonding arrangements. This interesting three-dimensional framework is characterized by seven types of intersecting tunnels, three of which are occupied by the barium cation, while the others are empty. It is important to know that one of the empty tunnels has a relatively large window with a minimum diagonal distance of 4.4 [angstrom], which facilitates a possible framework for a lithium ion insertion reaction. The barium atom has a 10-coordination sphere, BaO[sub 10], in which the oxygen atoms can be viewed as forming two intersecting pseudohexagonal planes. [beta]-BaV[sub 2](P[sub 2]O[sub 7])[sub 2] appears to form at a relatively higher temperature than its polymorph, [alpha]-BaV[sub 2](P[sub 2]O[sub 7])[sub 2]. A detailed structural analysis and structural comparison with the [alpha]-phase, as well as a brief comparison with SrV[sub 2](P[sub 2]O[sub 7])[sub 2], are presented.

  1. Intoxication by large amounts of barium nitrate overcome by early massive K supplementation and oral administration of magnesium sulphate.

    PubMed

    Payen, Christine; Dellinger, Arnaud; Pulce, Corine; Cirimele, Vincent; Carbonnel, Vincent; Kintz, Pascal; Descotes, Jacques

    2011-01-01

    Suicide by ingestion of barium is exceptionally rare. Adverse health effects depend on the solubility of the barium compound. Severe hypokalemia, which generally occurs within 2 hours after ingestion, is the predominating feature of acute barium toxicity, subsequently leading to adverse effects on muscular activity and cardiac automaticity. We report one case of acute poisoning with barium nitrate, a soluble barium compound. A 75-year-old woman was hospitalized after suicidal ingestion of a burrow mole fumigant containing 12.375 g of barium nitrate. About 1 hour post-ingestion, she was only complaining of abdominal pain. The ECG recording demonstrated polymorphic ventricular premature complexes (VPCs). Laboratory data revealed profound hypokalemia (2.1 mmol/L). She made a complete and uneventful recovery after early and massive potassium supplementation combined with oral magnesium sulphate to prevent barium nitrate absorption.

  2. The Evolving Mixture of Barium Isotopes in Milky Way Halo Stars

    NASA Astrophysics Data System (ADS)

    Choudhury, Zareen; Kirby, E. N.; Guhathakurta, P.

    2014-01-01

    Heavy metals in stars form through one of two types of neutron capture processes: the rapid r-process or slower s-process. The fraction of odd and even barium isotopes in stars can indicate which process predominantly contributed to a star’s heavy metals, since odd barium isotopes predominantly form through the r-process and even barium isotopes through the s-process. The “stellar model” predicts that older stars contain comparable amounts of odd and even barium isotopes, while the “classical model” states that they almost exclusively contain odd isotopes. This study investigated these competing models by analyzing high-resolution spectra of twelve Milky Way stars. These spectra were analyzed for the first time in this study. To quantify r- and s-process enrichment, we measured the odd barium isotope fraction in the stars by fitting models to the stars’ spectra. Generating models involved measuring the stars’ Doppler shift, resolution, and barium abundance. To reduce error margins we optimized resolution and barium abundance measurements by enhancing existing techniques through several rounds of revisions. Our results support the stellar model of heavy metal enrichment, and our proposed optimizations will enable future researchers to obtain a deeper understanding of chemical enrichment in the Universe. This research was supported by the Science Internship Program at the University of California Santa Cruz, Lick Observatory, and the National Science Foundation.

  3. Fabrication and characterization of cerium-doped barium titanate inverse opal by sol-gel method

    SciTech Connect

    Jin Yi; Zhu Yihua Yang Xiaoling; Li Chunzhong; Zhou Jinghong

    2007-01-15

    Cerium-doped barium titanate inverted opal was synthesized from barium acetate contained cerous acetate and tetrabutyl titanate in the interstitial spaces of a polystyrene (PS) opal. This procedure involves infiltration of precursors into the interstices of the PS opal template followed by hydrolytic polycondensation of the precursors to amorphous barium titanate and removal of the PS opal by calcination. The morphologies of opal and inverse opal were characterized by scanning electron microscope (SEM). The pores were characterized by mercury intrusion porosimetry (MIP). X-ray photoelectron spectroscopy (XPS) investigation showed the doping structure of cerium, barium and titanium. And powder X-ray diffraction allows one to observe the influence of doping degree on the grain size. The lattice parameters, crystal size and lattice strain were calculated by the Rietveld refinement method. The synthesis of cerium-doped barium titanate inverted opals provides an opportunity to electrically and optically engineer the photonic band structure and the possibility of developing tunable three-dimensional photonic crystal devices. - Graphical abstract: Cerium-doped barium titanate inverted opal was synthesized from barium acetate acid contained cerous acetate and tetrabutyl titanate in the interstitial spaces of a PS opal, which involves infiltration of precursors into the interstices of the PS opal template and removal of the PS opal by calcination.

  4. Bio-based barium alginate film: Preparation, flame retardancy and thermal degradation behavior.

    PubMed

    Liu, Yun; Zhang, Chuan-Jie; Zhao, Jin-Chao; Guo, Yi; Zhu, Ping; Wang, De-Yi

    2016-03-30

    A bio-based barium alginate film was prepared via a facile ionic exchange and casting approach. Its flammability, thermal degradation and pyrolysis behaviors, thermal degradation mechanism were studied systemically by limiting oxygen index (LOI), vertical burning (UL-94), microscale combustion calorimetry (MCC), thermogravimetric analysis (TGA) coupled with Fourier transform infrared analysis (FTIR) and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS). It showed that barium alginate film had much higher LOI value (52.0%) than that of sodium alginate film (24.5%). Moreover, barium alginate film passed the UL-94 V-0 rating, while the sodium alginate film showed no classification. Importantly, peak of heat release rate (PHRR) of barium alginate film in MCC test was much lower than that of sodium alginate film, suggested that introduction of barium ion into alginate film significantly decreased release of combustible gases. TG-FTIR and Py-GC-MS results indicated that barium alginate produced much less flammable products than that of sodium alginate in whole thermal degradation procedure. Finally, a possible degradation mechanism of barium alginate had been proposed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Magnetic properties of Ni substituted Y-type barium ferrite

    SciTech Connect

    Won, Mi Hee; Kim, Chul Sung

    2014-05-07

    Y-type barium hexaferrite is attractive material for various applications, such as high frequency antennas and RF devices, because of its interesting magnetic properties. Especially, Ni substituted Y- type hexaferrites have higher magnetic ordering temperature than other Y-type. We have investigated macroscopic and microscopic properties of Y-type barium hexaferrite. Ba{sub 2}Co{sub 2−x}Ni{sub x}Fe{sub 12}O{sub 22} (x = 0, 0.5, 1.0, 1.5, and 2.0) samples are prepared by solid-state reaction method and studied by X-ray diffraction (XRD), vibrating sample magnetometer, and Mössbauer spectroscopy, as well as a network analyzer for high frequency characteristics. The XRD pattern is analyzed by Rietveld refinement method and confirms the hexagonal structure with R-3m. The hysteresis curve shows ferrimagnetic behavior. Saturation magnetization (M{sub s}) decreases with Ni contents. Ni{sup 2+}, which preferentially occupies the octahedral site with up-spin sub-lattice, has smaller spin value S of 1 than Co{sup 2+} having S = 3/2. The zero-field-cooled (ZFC) measurement of Ba{sub 2}Co{sub 1.5}Ni{sub 0.5}Fe{sub 12}O{sub 22} shows that Curie and spin transition temperatures are found to be 718 K and 209 K, respectively. The Curie temperature T{sub C} is increased with Ni contents, while T{sub S} is decreased with Ni. The Mössbauer spectra were measured at various temperatures and fitted by using a least-squares method with six sextet of six Lorentzian lines for Fe sites, corresponding to the 3b{sub VI}, 6c{sub IV}*, 6c{sub VI}, 18h{sub VI}, 6c{sub IV}, and 3a{sub IV} sites at below T{sub C}. From Mössbauer measurements, we confirmed the spin state of Fe ion to be Fe{sup 3+} and obtained the isomer shift (δ), magnetic hyperfine field (H{sub hf}), and the occupancy ratio of Fe ions at six sub-lattices. The complex permeability and permittivity are measured between 100 MHz and 4 GHz, suggesting that Y-type barium hexaferrite is promising for antenna

  6. Magnetic properties of Ni substituted Y-type barium ferrite

    NASA Astrophysics Data System (ADS)

    Won, Mi Hee; Kim, Chul Sung

    2014-05-01

    Y-type barium hexaferrite is attractive material for various applications, such as high frequency antennas and RF devices, because of its interesting magnetic properties. Especially, Ni substituted Y- type hexaferrites have higher magnetic ordering temperature than other Y-type. We have investigated macroscopic and microscopic properties of Y-type barium hexaferrite. Ba2Co2-xNixFe12O22 (x = 0, 0.5, 1.0, 1.5, and 2.0) samples are prepared by solid-state reaction method and studied by X-ray diffraction (XRD), vibrating sample magnetometer, and Mössbauer spectroscopy, as well as a network analyzer for high frequency characteristics. The XRD pattern is analyzed by Rietveld refinement method and confirms the hexagonal structure with R-3m. The hysteresis curve shows ferrimagnetic behavior. Saturation magnetization (Ms) decreases with Ni contents. Ni2+, which preferentially occupies the octahedral site with up-spin sub-lattice, has smaller spin value S of 1 than Co2+ having S = 3/2. The zero-field-cooled (ZFC) measurement of Ba2Co1.5Ni0.5Fe12O22 shows that Curie and spin transition temperatures are found to be 718 K and 209 K, respectively. The Curie temperature TC is increased with Ni contents, while TS is decreased with Ni. The Mössbauer spectra were measured at various temperatures and fitted by using a least-squares method with six sextet of six Lorentzian lines for Fe sites, corresponding to the 3bVI, 6cIV*, 6cVI, 18hVI, 6cIV, and 3aIV sites at below TC. From Mössbauer measurements, we confirmed the spin state of Fe ion to be Fe3+ and obtained the isomer shift (δ), magnetic hyperfine field (Hhf), and the occupancy ratio of Fe ions at six sub-lattices. The complex permeability and permittivity are measured between 100 MHz and 4 GHz, suggesting that Y-type barium hexaferrite is promising for antenna applications in UHF band.

  7. Improved Manganese Phosphate Coatings

    DTIC Science & Technology

    1975-04-01

    Conversion coatings 3 . Phosphating bath 20 AGrjC onln odd*. ta It .. c..soMV midP 1J.,alft. by block noc.mb) Work was conducted to determine the mechanism by...34 TABULAR DATA Table I Analyses of Solution and Coating for Phosphating Baths 4 of Di-ferlng Compositions 11 Atomic Absorption...manganese and iron phosphate coating: k * a. Mn(H 2PO4) 2 Nn-P0 4 + H3PO0 k2 k) b. 3MnHPO4 - Mn3 (P04) 2 + H3i’O4 k4 k5 c. Fe(H 2PO4) 2 -01 FeHPO4

  8. Codeine dihydrogen phosphate hemihydrate.

    PubMed

    Langes, Christoph; Gelbrich, Thomas; Griesser, Ulrich J; Kahlenberg, Volker

    2009-08-01

    The cation of the title structure [systematic name: (5alpha,6alpha)-6-hydroxy-7,8-didehydro-4,5-epoxy-3-methoxy-17-methylmorphinanium dihydrogen phosphate hemihydrate], C18H22NO3+.H2PO4-.0.5H2O, has a T-shaped conformation. The dihydrogen phosphate anions are linked by O-H...O hydrogen bonds to give an extended ribbon chain. The codeine cations are linked together by O-H...O hydrogen bonds into a zigzag chain. There are also N-H...O bonds between the two types of hydrogen-bonded units. Additionally, they are connected to one another via O...H-O-H...O bridging water molecules. The asymmetric unit contains two codeine hydrogen cations, two dihydrogen phosphate anions and one water molecule. This study shows that the water molecules are firmly bound within a complex three-dimensional hydrogen-bonded framework.

  9. Phosphate Mines, Jordan

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Jordan's leading industry and export commodities are phosphate and potash, ranked in the top three in the world. These are used to make fertilizer. The Jordan Phosphate Mines Company is the sole producer, having started operations in 1935. In addition to mining activities, the company produces phosphoric acid (for fertilizers, detergents, pharmaceuticals), diammonium phosphate (for fertilizer), sulphuric acid (many uses), and aluminum fluoride (a catalyst to make aluminum and magnesium).

    The image covers an area of 27.5 x 49.4 km, was acquired on September 17, 2005, and is located near 30.8 degrees north latitude, 36.1 degrees east longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  10. Fundamentals of phosphate transfer.

    PubMed

    Kirby, Anthony J; Nome, Faruk

    2015-07-21

    Historically, the chemistry of phosphate transfer-a class of reactions fundamental to the chemistry of Life-has been discussed almost exclusively in terms of the nucleophile and the leaving group. Reactivity always depends significantly on both factors; but recent results for reactions of phosphate triesters have shown that it can also depend strongly on the nature of the nonleaving or "spectator" groups. The extreme stabilities of fully ionised mono- and dialkyl phosphate esters can be seen as extensions of the same effect, with one or two triester OR groups replaced by O(-). Our chosen lead reaction is hydrolysis-phosphate transfer to water: because water is the medium in which biological chemistry takes place; because the half-life of a system in water is an accepted basic index of stability; and because the typical mechanisms of hydrolysis, with solvent H2O providing specific molecules to act as nucleophiles and as general acids or bases, are models for reactions involving better nucleophiles and stronger general species catalysts. Not least those available in enzyme active sites. Alkyl monoester dianions compete with alkyl diester monoanions for the slowest estimated rates of spontaneous hydrolysis. High stability at physiological pH is a vital factor in the biological roles of organic phosphates, but a significant limitation for experimental investigations. Almost all kinetic measurements of phosphate transfer reactions involving mono- and diesters have been followed by UV-visible spectroscopy using activated systems, conveniently compounds with good leaving groups. (A "good leaving group" OR* is electron-withdrawing, and can be displaced to generate an anion R*O(-) in water near pH 7.) Reactivities at normal temperatures of P-O-alkyl derivatives-better models for typical biological substrates-have typically had to be estimated: by extended extrapolation from linear free energy relationships, or from rate measurements at high temperatures. Calculation is free

  11. On the nature of striae in strontium barium niobate

    SciTech Connect

    Monchamp, R.R.; Mihalik, G.B.; Franks, L.A.

    1993-12-31

    Strontium barium niobate crystals were grown by the Czochralski technique. These crystals were 15--20 mm in diameter and 25 to 75 mm long. Two types stride, designated as coarse and fine, were characterized. The coarse stride are optically dense and are spaced by 100 to 500 {mu}m apart; the fine striae are optically less dense and spaced 5--50 {mu}m apart. The origins of the stride are attributed to thermal fluctuations in the melt related to the control system and to rotation of the growing crystal in non-isothermal radial gradients. Analysis of the crystals would indicated that the coarse striae may contain increased concentrations of sodium.

  12. Nonlinear optical properties of calcium barium niobate epitaxial thin films.

    PubMed

    Bancelin, Stéphane; Vigne, Sébastien; Hossain, Nadir; Chaker, Mohammed; Légaré, François

    2016-07-25

    We investigate the potential of epitaxial calcium barium niobate (CBN) thin film grown by pulsed laser deposition for optical frequency conversion. Using second harmonic generation (SHG), we analyze the polarization response of the generated signal to determine the ratios d15 / d32 and d33 / d32 of the three independent components of the second-order nonlinear susceptibility tensor in CBN thin film. In addition, a detailed comparison to the signal intensity obtained in a y-cut quartz allows us to measure the absolute value of these components in CBN thin film: d15 = 5 ± 2 pm / V, d32 = 3.1 ± 0.6 pm / V and d33 = 9 ± 2 pm / V.

  13. Impact of vanadium ions in barium borate glass.

    PubMed

    Abdelghany, A M; Hammad, Ahmed H

    2015-02-25

    Combined optical and infrared spectral measurements of prepared barium borate glasses containing different concentrations of V2O5 were carried out. Vanadium containing glasses exhibit extended UV-visible (UV/Vis.) bands when compared with base binary borate glass. UV/Vis. spectrum shows the presence of an unsymmetrical strong UV broad band centered at 214 nm attributed to the presence of unavoidable trace iron impurities within the raw materials used for the preparation of such glass. The calculated direct and indirect optical band gaps are found to decrease with increasing the vanadium content (2.9:137 for indirect and 3.99:2.01 for direct transition). This change was discussed in terms of structural changes in the glass network. Infrared absorption spectra of the glasses reveal the appearance of both triangular and tetrahedral borate units. Electron spin resonance analyses indicate the presence of unpaired species in sufficient quantity to be identified and to confirm the spectral data.

  14. Synthesis and optical study of barium magnesium aluminate blue phosphors

    SciTech Connect

    Jeet, Suninder Pandey, O. P.; Sharma, Manoj

    2015-05-15

    Europium doped barium magnesium aluminate (BaMgAl{sub 10}O{sub 17}:Eu{sup 2+}) phosphor was prepared via solution combustion method at 550°C using urea as a fuel. Morphological and optical properties of the prepared sample was studied by X-ray diffraction (XRD), Transmission electron microscopy (TEM) and Photoluminescence spectroscopy (PL). XRD result showed the formation of pure phase BaMgAl{sub 10}O{sub 17}(JCPDS 26-0163) along with an additional phase BaAl{sub 2}O{sub 4}(JCPDS 01-082-1350). TEM image indicated the formation of faceted particles with average particle size 40 nm. From PL spectra, a broad emission band obtained at about 450 nm attributes to 4f{sup 6} 5d → 4f{sup 7} transition of Eu{sup 2+} which lies in the blue region of the visible spectrum.

  15. Microwave dielectric properties of graded barium strontium titanate films

    NASA Astrophysics Data System (ADS)

    Cole, M. W.; Weiss, C. V.; Ngo, E.; Hirsch, S.; Coryell, L. A.; Alpay, S. P.

    2008-05-01

    Compositionally graded barium strontium titanate (BaxSr1-xTiO3 or BST) multilayers (5mol% MgO doped and undoped) were prepared via metallo-organic solution deposition on Pt-Si substrates and characterized electrically at 0.5, 5, and 10GHz. For the undoped BST multilayers, the small-signal dielectric response, tunability, and the loss tangent at 10GHz were 261, 25% at 1778kV/cm, and 0.078, respectively. On the other hand, the Mg-doped BST multilayers displayed a significant improvement in the loss characteristics at 10GHz (0.039) but the dielectric response and its tunability were lower (189 and 15%, respectively, at 1778kV/cm).

  16. Dynamics of the CRRES barium releases in the magnetosphere

    NASA Technical Reports Server (NTRS)

    Fuselier, S. A.; Mende, S. B.; Geller, S. P.; Miller, M.; Hoffman, R. A.; Wygant, J. R.; Pongratz, M.; Meredith, N. P.; Anderson, R. R.

    1994-01-01

    The Combined Release and Radiation Effects Satellite (CRRES) G-2, G-3, and G-4 ionized and neutral barium cloud positions are triangulated from ground-based optical data. From the time history of the ionized cloud motion perpendicular to the magnetic field, the late time coupling of the ionized cloud with the collisionless ambient plasma in the magnetosphere is investigated for each of the releases. The coupling of the ionized clouds with the ambient medium is quantitatively consistent with predictions from theory in that the coupling time increases with increasing distance from the Earth. Quantitative comparison with simple theory for the couping time also yields reasonable agreement. Other effects not predicted by the theory are discussed in the context of the observations.

  17. Pulsating aurora induced by upper atmospheric barium releases

    NASA Technical Reports Server (NTRS)

    Deehr, C.; Romick, G.

    1977-01-01

    The paper reports the apparent generation of pulsating aurora by explosive releases of barium vapor near 250 km altitude. This effect occurred only when the explosions were in the path of precipitating electrons associated with the visible aurora. Each explosive charge was a standard 1.5 kg thermite mixture of Ba and CuO with an excess of Ba metal which was vaporized and dispersed by the thermite explosion. Traces of Sr, Na, and Li were added to some of the charges, and monitoring was achieved by ground-based spectrophotometric observations. On March 28, 1976, an increase in emission at 5577 A and at 4278 A was observed in association with the first two bursts, these emissions pulsating with roughly a 10 sec period for approximately 60 to 100 sec after the burst.

  18. Impact of vanadium ions in barium borate glass

    NASA Astrophysics Data System (ADS)

    Abdelghany, A. M.; Hammad, Ahmed H.

    2015-02-01

    Combined optical and infrared spectral measurements of prepared barium borate glasses containing different concentrations of V2O5 were carried out. Vanadium containing glasses exhibit extended UV-visible (UV/Vis.) bands when compared with base binary borate glass. UV/Vis. spectrum shows the presence of an unsymmetrical strong UV broad band centered at 214 nm attributed to the presence of unavoidable trace iron impurities within the raw materials used for the preparation of such glass. The calculated direct and indirect optical band gaps are found to decrease with increasing the vanadium content (2.9:137 for indirect and 3.99:2.01 for direct transition). This change was discussed in terms of structural changes in the glass network. Infrared absorption spectra of the glasses reveal the appearance of both triangular and tetrahedral borate units. Electron spin resonance analyses indicate the presence of unpaired species in sufficient quantity to be identified and to confirm the spectral data.

  19. Coralline barium records temporal variability in equatorial Pacific upwelling

    NASA Astrophysics Data System (ADS)

    Lea, David W.; Shen, Glen T.; Boyle, Edward A.

    1989-08-01

    LATTICE-BOUND cadmium in scleractinian corals has been shown to be a sensitive tracer of historical changes in the nutrient content of surface waters1,2. Barium also substitutes into the lattice of aragonite reef-building corals because there is solid solution between orthorhombic BaCO3 (witherite) and CaCO3(aragonite)3. It is expected that the substitution should be proportional to the Ba content of sea water, which increases from low values in warm surface waters to higher values in cold deep waters. Here we present a high-resolution coralline Ba record from the Galapagos Islands spanning the period 1965-1978. Coralline Ba/Ca tracks historical sea surface temperatures, reflecting the vertical displacement of warm nutrient-poor surface waters by cold, nutrient-rich source waters. Differences between coralline Ba and Cd records may be due to preferential uptake of Cd by phytoplankton during times of lower surface nutrients.

  20. A buffer gas cooled beam of barium monohydride

    NASA Astrophysics Data System (ADS)

    Iwata, Geoffrey; Tarallo, Marco; Zelevinsky, Tanya

    2016-05-01

    Significant advances in direct laser cooling of diatomic molecules have opened up a wide array of molecular species to precision studies spanning many-body physics, quantum collisions and ultracold dissociation. We present a cryogenic beam source of barium monohydride (BaH), and study laser ablation of solid precursor targets as well as helium buffer gas cooling dynamics. Additionally, we cover progress towards a molecular magneto-optical trap, with spectroscopic studies of relevant cooling transitions in the B2 Σ <--X2 Σ manifold in laser ablated molecules, including resolution of hyperfine structure and precision measurements of the vibrational Frank-Condon factors. Finally, we examine the feasibility of photo dissociation of trapped BaH molecules to yield optically accessible samples of ultracold hydrogen.

  1. Strontium and barium iodide high light yield scintillators

    NASA Astrophysics Data System (ADS)

    Cherepy, Nerine J.; Hull, Giulia; Drobshoff, Alexander D.; Payne, Stephen A.; van Loef, Edgar; Wilson, Cody M.; Shah, Kanai S.; Roy, Utpal N.; Burger, Arnold; Boatner, Lynn A.; Choong, Woon-Seng; Moses, William W.

    2008-02-01

    Europium-doped strontium and barium iodide are found to be readily growable by the Bridgman method and to produce high scintillation light yields. SrI2(Eu ) emits into the Eu2+ band, centered at 435nm, with a decay time of 1.2μs and a light yield of ˜90000photons/MeV. It offers energy resolution better than 4% full width at half maximum at 662keV, and exhibits excellent light yield proportionality. BaI2(Eu ) produces >30000photons/MeV into the Eu2+ band at 420nm (<1μs decay). An additional broad impurity-mediated recombination band is present at 550nm (>3μs decay), unless high-purity feedstock is used.

  2. Spectroscopic study of Er:Sm doped barium fluorotellurite glass.

    PubMed

    Bahadur, A; Dwivedi, Y; Rai, S B

    2010-09-15

    In this paper, we report the physical and spectroscopic properties of Er(3+), Sm(3+) and Er(3+):Sm(3+) ions codoped barium fluorotellurite (BFT) glasses. Different Stokes and anti-Stokes emissions were observed under 532 nm and 976 nm laser excitations. Energy transfer from Er(3+) ion to Sm(3+) ion was confirmed on the basis of luminescence intensity variation and decay curve analysis in both the cases. Under green (532 nm) excitation emission intensity of Sm(3+) ion bands improves whereas on NIR (976 nm) excitation new emission bands of Sm(3+) ions were observed in Er:Sm codoped samples. Ion interactions and the different energy transfer parameters were also calculated. Copyright 2010 Elsevier B.V. All rights reserved.

  3. Synthesis, microstructure and dielectric properties of zirconium doped barium titanate

    SciTech Connect

    Kumar, Rohtash; Asokan, K.; Patnaik, S.; Birajdar, Balaji

    2016-05-23

    We report on synthesis, microstructural and relaxor ferroelectric properties of Zirconium(Zr) doped Barium Titanate (BT) samples with general formula Ba(Ti{sub 1-x}Zr{sub x})O{sub 3} (x=0.20, 0.35). These lead-free ceramics were prepared by solid state reaction route. The phase transition behavior and temperature dependent dielectric properties and composition dependent ferroelectric properties were investigated. XRD analysis at room temperature confirms phase purity of the samples. SEM observations revealed retarded grain growth with increasing Zr mole fraction. Dielectric properties of BZT ceramics is influenced significantly by small addition of Zr mole fraction. With increasing Zr mole fraction, dielectric constant decreases while FWHM and frequency dispersion increases. Polarization vs electric field hysteresis measurements reveal ferroelectric relaxor phase at room temperature. The advantages of such substitution maneuvering towards optimizing ferroelectric properties of BaTiO{sub 3} are discussed.

  4. Dielectric behavior of barium modified strontium bismuth titanate ceramic

    SciTech Connect

    Nayak, P.; Badapanda, T.; Anwar, S.; Panigrahi, S.

    2014-04-24

    Barium Modified Strontium Bismuth Titanate(SBT) ceramic with general formula Sr1−xBaxBi4Ti4O15 is prepared by solid state reaction route. The structural analysis of the ceramics was done by X-ray diffraction technique. The X-ray patterns show that all the compositions are of single phase with orthorhombic structure. The temperature dependent dielectric behavior shows that the transition temperature decreases with Ba content but the maximum dielectric constant increases. The decreases of the transition with increase in Ba{sup 2+} ion, may be due to the decrease of orthorhombicity by the incorporation of Ba{sup 2+} ion in SBT lattice.

  5. Niobium and rubidium in the barium star Zeta Capricorni

    NASA Astrophysics Data System (ADS)

    Smith, V. V.; Lambert, D. L.

    1984-03-01

    An abundance analysis of the elements Rb to Nb (relative to the G-giant standard ɛ Vir) has been carried out for the barium star ζ Cap using low-noise, high-resolution Digicon and Reticon spectra. Tech's (1971) low abundance of Nb in ζ Cap suggests that the s-process ceased less than about a million years ago. The authors' improved analysis finds a higher Nb abundance consistent with the complete decay of 93Zr to 93Nb; i.e., more than 3×106 years have elapsed since the principal phase of s-processing. The abundance of Rb suggests a neutron density of N(n) ≡ 107cm-3 for the s-process site at the close of s-processing.

  6. Barium titanate nanocomposite capacitor FY09 year end report.

    SciTech Connect

    Stevens, Tyler E.; DiAntonio, Christopher Brian; Yang, Pin; Chavez, Tom P.; Winter, Michael R.; Monson, Todd C.; Roesler, Alexander William; Fellows, Benjamin D.

    2009-11-01

    This late start RTBF project started the development of barium titanate (BTO)/glass nanocomposite capacitors for future and emerging energy storage applications. The long term goal of this work is to decrease the size, weight, and cost of ceramic capacitors while increasing their reliability. Ceramic-based nanocomposites have the potential to yield materials with enhanced permittivity, breakdown strength (BDS), and reduced strain, which can increase the energy density of capacitors and increase their shot life. Composites of BTO in glass will limit grain growth during device fabrication (preserving nanoparticle grain size and enhanced properties), resulting in devices with improved density, permittivity, BDS, and shot life. BTO will eliminate the issues associated with Pb toxicity and volatility as well as the variation in energy storage vs. temperature of PZT based devices. During the last six months of FY09 this work focused on developing syntheses for BTO nanoparticles and firing profiles for sintering BTO/glass composite capacitors.

  7. Small polarons and point defects in barium cerate

    NASA Astrophysics Data System (ADS)

    Swift, Michael; Janotti, Anderson; Van de Walle, Chris G.

    2015-12-01

    Barium cerate (BaCeO3) is a well-known ionic conductor of both hydrogen and oxygen. In applications, it is frequently doped (for instance with Y) to increase stability and promote diffusion. However, the effects of doping and native defects are not fully understood. Computational studies have been stymied by the nature of the conduction band, which is made up of cerium 4 f states. These states present a challenge to ab initio techniques based on density functional theory within the standard approximations for exchange and correlation. Using a hybrid functional, we investigate the effects of hydrogen impurities and native defects on the electrical and optical properties of BaCeO3. We discuss the tendency of excess electrons or holes to localize in the form of small polarons. We also explore the interactions of polarons with hydrogen impurities and oxygen vacancies, and their impact on luminescence properties.

  8. A new type of microphone using flexoelectric barium strontium titnate

    NASA Astrophysics Data System (ADS)

    Kwon, Seol ryung; Huang, Wenbin; Zhang, Shujun; Yuan, Fuh-Gwo; Jiang, Xiaoning

    2014-03-01

    A flexoelectric bridge-structured microphone using bulk barium strontium titanate (Ba0.65Sr0.35TiO3 or BST) ceramic was investigated in this study. The flexoelectric microphone was installed in an anechoic box and exposed to the sound pressure emitted from a loud speaker. Charge sensitivity of the flexoelectric microphone was measured and calibrated using a reference microphone. The 1.5 mm×768 μm×50 μm micro-machined bridge-structured flexoelectric microphone has a sensitivity of 0.92 pC/Pa, while its resonance frequency was calculated to be 98.67 kHz. The analytical and experimental results show that the flexoelectric microphone has both high sensitivity and broad bandwidth, indicating that flexoelectric microphones are potential candidates for many applications.

  9. Synthesis and optical study of barium magnesium aluminate blue phosphors

    NASA Astrophysics Data System (ADS)

    Jeet, Suninder; Sharma, Manoj; Pandey, O. P.

    2015-05-01

    Europium doped barium magnesium aluminate (BaMgAl10O17:Eu2+) phosphor was prepared via solution combustion method at 550°C using urea as a fuel. Morphological and optical properties of the prepared sample was studied by X-ray diffraction (XRD), Transmission electron microscopy (TEM) and Photoluminescence spectroscopy (PL). XRD result showed the formation of pure phase BaMgAl10O17(JCPDS 26-0163) along with an additional phase BaAl2O4(JCPDS 01-082-1350). TEM image indicated the formation of faceted particles with average particle size 40 nm. From PL spectra, a broad emission band obtained at about 450 nm attributes to 4f6 5d → 4f7 transition of Eu2+ which lies in the blue region of the visible spectrum.

  10. Preparation and magnetic properties of barium hexaferrite nanorods

    SciTech Connect

    Mu Guohong Pan Xifeng; Chen Na; Gan Keke; Gu Mingyuan

    2008-06-03

    The barium hexaferrite nanorods were successfully prepared by sol-gel technique combined with polymethylmethacrylate as template. The crystal structure, morphology and magnetic properties of BaFe{sub 12}O{sub 19} with different shape were investigated with X-ray diffraction, field emission scanning electron microscope and vibrating sample magnetometry. The results show that diameters and lengths of magnetic nanorods are about 60 nm and 300 nm, respectively. The coercivity of rod-shaped BaFe{sub 12}O{sub 19} is increased to 5350 Oe, in comparison with 4800 Oe with plate-shape. The formation mechanism of BaFe{sub 12}O{sub 19} nanorods and reasons resulting in high coercivity are discussed.

  11. Dissociation behavior of protons incorporated in yttrium doped barium zirconate

    NASA Astrophysics Data System (ADS)

    Ishiyama, T.; Kishimoto, H.; Develos-Bagarinao, K.; Yamaji, K.; Yamaguchi, T.; Fujishiro, Y.

    2017-08-01

    The dissociation behavior of protons incorporated in yttrium-doped barium zirconate (BZY20) was investigated via combination of in-situ diffuse reflectance Fourier transform infrared spectroscopy (FT-IR) and evolved gas analysis. The vicinities of dopant or host ions were considered as sites of proton dissolution. The temperature dependence of the dissociation of protons from each site was evaluated. Protons which were considered to have dissolved in the vicinity of dopant ions were easily removed and dissociated as water. On the other hand, those which dissolved in the vicinity of host ions were dissociated as hydrogen at high temperatures. Such dissociation behavior was also detected after using D2O saturated gas for pre-treatment. These results suggest that some protons which dissolved in the perovskite oxide could dissociate as hydrogen without forming oxygen vacancies. (131words)

  12. Analysis of barium hydroxide and calcium hydroxide slurry carbonation reactors

    SciTech Connect

    Patch, K.D.; Hart, R.P.; Schumacher, W.A.

    1980-05-01

    The removal of CO/sub 2/ from air was investigated by using a continuous-agitated-slurry carbonation reactor containing either barium hydroxide (Ba(OH)/sub 2/) or calcium hydroxide (Ca(OH)/sub 2/). Such a process would be applied to scrub /sup 14/CO/sub 2/ from stack gases at nuclear-fuel reprocessing plants. Decontamination factors were characterized for reactor conditions which could alter hydrodynamic behavior. An attempt was made to characterize reactor performance with models assuming both plug flow and various degrees of backmixing in the gas phase. The Ba(OH)/sub 2/ slurry enabled increased conversion, but apparently the process was controlled under some conditions by phenomena differing from those observed for carbonation by Ca(OH)/sub 2/. Overall reaction mechanisms are postulated.

  13. Brillouin function characteristics for La-Co substituted barium hexaferrites

    SciTech Connect

    Wu, Chuanjian E-mail: ksun@uestc.edu.cn; Yu, Zhong; Sun, Ke E-mail: ksun@uestc.edu.cn; Guo, Rongdi; Jiang, Xiaona; Lan, Zhongwen; Yang, Yan

    2015-09-14

    La-Co substituted barium hexaferrites with the chemical formula of Ba{sub 1−x}La{sub x}Fe{sub 12−x}Co{sub x}O{sub 19} (x = 0.0, 0.1, 0.3, and 0.5), prepared by a conventional ceramic method, were systematically investigated by Raman spectra, X-ray photoelectron spectroscopy, Rietveld refinement of X-ray diffraction patterns, and vibrating sample magnetometer. The result manifests that all the compounds are crystallized in magnetoplumbite hexagonal structure. Trivalent cobalt ions prevailingly occupy the 2a, 4f{sub 1}, and 12k sites. According to Néel model of collinear-spin ferrimagnetism, the molecular-field coefficients ω{sub bf2}, ω{sub kf1}, ω{sub af1}, ω{sub kf2}, and ω{sub bk} of La-Co substituted barium hexaferrites have been calculated using the nonlinear fitting method, and the magnetic moment of five sublattices (2a, 2b, 4f{sub 1}, 4f{sub 2}, and 12k) versus temperature T has been also investigated. The fitting results are coincided well with the experimental data. Moreover, with the increase of La-Co substitution amount x, the molecular-field coefficients ω{sub bf2} and ω{sub af1} decrease constantly, while the molecular-field coefficients ω{sub kf1}, ω{sub kf2}, and ω{sub bk} show a slight change.

  14. BD-21 3873: another yellow-symbiotic barium star.

    NASA Astrophysics Data System (ADS)

    Smith, V. V.; Cunha, K.; Jorissen, A.; Boffin, H. M. J.

    1997-08-01

    An abundance analysis of the yellow symbiotic system BD-21 3873 reveals it to be a metal-poor K-giant ([Fe/H]=-1.3) which is enriched in the heavy s-process elements. In that respect, this star appears to be a twin of AG Dra, another yellow symbiotic system analyzed in a previous paper (Smith et al., 1996A&A...315..179S). The heavy-element abundance distributions of AG Dra and BD-21 3873 are almost identical, and are best reproduced by a s-process with a neutron exposure parameter of 1.2-1.3mb^-1^ and a neutron density logN_n_=8.3 (as derived from the Rb/Zr ratio). These two systems thus link the symbiotic stars to the binary barium and CH stars which are also s-process enriched. These binary systems, which exhibit overabundances of the heavy elements, owe their abundance peculiarities to mass transfer from thermally-pulsing asymptotic giant branch stars, which have since evolved to become white-dwarf companions of the cool stars we now view as the chemically-peculiar primaries. The spectroscopic orbits of BD-21 3873 (derived from CORAVEL measurements) and AG Dra are similar to those of barium and CH stars. With an orbital period of 281.6d, BD-21 3873 is one of the closest systems in these families, and its light curve indeed suggests that variations due to reflection and ellipticity effects are present. The amplitude of the ellipsoidal variations indicates that the giant must be close to filling its Roche lobe. However, no acceptable solution simultaneously satisfies the constraints from the light curve, the orbital elements and the evolutionary tracks in the framework of the standard Roche lobe geometry. We suggest that this discrepancy may be resolved by taking into account the deformation of the Roche lobe caused by the force driving the large mass loss of the giant.

  15. Barium tagging in solid xenon for the EXO experiment

    NASA Astrophysics Data System (ADS)

    Mong, Brian

    2011-07-01

    Neutrinoless double beta decay experiments are searching for rare decay modes never before observed to uncover the absolute mass of the neutrino, as well as to discover if it is a Majorana fermion. Detection of the daughter nucleus can help provide positive identification of this event over most radioactive backgrounds. The goal of the Enriched Xenon Observatory (EXO) is to measure the rate of 0nubetabeta decay in 136Xe, incorporating 136Ba daughter identification by laser induced fluorescence spectroscopy. Here, we investigate a technique in which the 136Ba daughter is grabbed with a cryogenic probe by freezing it in solid xenon ice, and detected directly in the solid xenon. The absorption and fluorescence spectra of barium in solid xenon were observed for the first time in this work. Identification of the 6s 2 1S0 → 6s6p 1P 1 transition in both absorption (558 nm) and emission spectra (594 nm) were made. Additional blue absorption and emission lines were observed, but their transitions were not identified. Saturation of the 6s2 1S0 → 6s6p 1P1 transition was not observed with increased excitation rates using resonance excitation at 558˜nm. From this a limit on the metastable decay rate was deduced to be greater than 104 s-1. Finally a fluorescence spectrum was obtained from a sample with only 20,000 atoms in the laser beam. With potential improvements of 107 in detection efficiency, single barium atom detection seems possible in solid xenon. A fiber probe detector based on a bare single mode fiber was also constructed and tested with fluorescing dye molecules. Successful detection of a few dye molecules in solution at the probe tip was demonstrated.

  16. DIAGNOSTIC ACCURACY OF BARIUM ENEMA FINDINGS IN HIRSCHSPRUNG'S DISEASE.

    PubMed

    Peyvasteh, Mehran; Askarpour, Shahnam; Ostadian, Nasrollah; Moghimi, Mohammad-Reza; Javaherizadeh, Hazhir

    2016-01-01

    Hirschsprung's disease is the most common cause of pediatric intestinal obstruction. Contrast enema is used for evaluation of the patients with its diagnosis. To evaluate sensitivity, specificity, positive predictive value, and negative predictive value of radiologic findings for diagnosis of Hirschsprung in patients underwent barium enema. This cross sectional study was carried out in Imam Khomeini Hospital for one year starting from 2012, April. Sixty patients were enrolled. Inclusion criteria were: neonates with failure to pass meconium, abdominal distention, and refractory constipation who failed to respond with medical treatment. Transitional zone, delay in barium evacuation after 24 h, rectosigmoid index (maximum with of the rectum divided by maximum with of the sigmoid; abnormal if <1), and irregularity of mucosa (jejunization) were evaluated in barium enema. Biopsy was obtained at three locations apart above dentate line. PPV, NPV, specificity , and sensitivity was calculated for each finding. Mean age of the cases with Hirschsprung's disease and without was 17.90±18.29 months and 17.8±18.34 months respectively (p=0.983). It was confirmed in 30 (M=20, F=10) of cases. Failure to pass meconium was found in 21(70%) cases. Sensitivity, specificity, PPV, and NPV were 90%, 80%, 81.8% and 88.8% respectively for transitional zone in barium enema. Sensitivity, specificity, PPV, and NPV were 76.7%, 83.3%, 78.1% and 82.1% respectively for rectosigmoid index .Sensitivity, specificity, PPV, and NPV were 46.7%, 100%, 100% and 65.2% respectively for irregular contraction detected in barium enema. Sensitivity, specificity, PPV, and NPV were 23.3%, 100%, 100% and 56.6% respectively for mucosal irregularity in barium enema. The most sensitive finding was transitional zone. The most specific findings were irregular contraction, mucosal irregularity, and followed by cobblestone appearance. A doença de Hirschsprung é a causa mais comum de obstrução intestinal pedi

  17. Domestic phosphate deposits

    USGS Publications Warehouse

    McKelvey, V.E.; Cathcart, J.B.; Altschuler, Z.S.; Swanson, R.W.; Lutz, Katherine

    1953-01-01

    Most of the worlds phosphate deposits can be grouped into six types: 1) igneous apatite deposits; 2) marine phosphorites; 3) residual phosphorites; 4) river pebble deposits; 5) phosphatized rock; and 6) guano. The igneous apatites and marine phosphorites form deposits measurable in millions or billions of tons; the residual deposits are measurable in thousands or millions; and the other types generally only in thousands of tons. Igneous apatite deposits have been mined on a small scale in New York, New Jersey, and Virginia. Marine phosphorites have been mined in Montana, Idaho, Utah, Wyoming, Arkansas, Tennessee, North Carolina, South Carolina, Georgia, and Florida. Residual phosphorites have been mined in Tennessee, Pennsylvania, and Florida. River pebble has been produced in South Carolina and Florida; phosphatized rock in Tennessee and Florida; and guano in New Mexico and Texas. Present production is limited almost entirely to Florida, Tennessee, Montana, Idaho, and Wyoming. Incomplete but recently partly revised estimates indicate the presence of about 5 billion tons of phosphate deposits in the United States that is minable under present economic conditions. Deposits too lean in quality or thickness to compete with those in the western and southeastern fields probably contain tens of billions of tons.

  18. 21 CFR 201.304 - Tannic acid and barium enema preparations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... added to barium enemas to improve X-ray pictures. Tannic acid is capable of causing diminished liver... use in enemas. Tannic acid for rectal use to enhance X-ray visualization is regarded as a new...

  19. 21 CFR 201.304 - Tannic acid and barium enema preparations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... added to barium enemas to improve X-ray pictures. Tannic acid is capable of causing diminished liver... use in enemas. Tannic acid for rectal use to enhance X-ray visualization is regarded as a new...

  20. 21 CFR 201.304 - Tannic acid and barium enema preparations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... added to barium enemas to improve X-ray pictures. Tannic acid is capable of causing diminished liver... use in enemas. Tannic acid for rectal use to enhance X-ray visualization is regarded as a new...

  1. 21 CFR 201.304 - Tannic acid and barium enema preparations.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... added to barium enemas to improve X-ray pictures. Tannic acid is capable of causing diminished liver... use in enemas. Tannic acid for rectal use to enhance X-ray visualization is regarded as a new...

  2. Comparison of flow-controlled calcium and barium carbonate precipitation patterns

    NASA Astrophysics Data System (ADS)

    Schuszter, G.; De Wit, A.

    2016-12-01

    Various precipitation patterns can be obtained in flow conditions when injecting a solution of sodium carbonate in a confined geometry initially filled with a solution of either barium or calcium chloride. We compare here the barium and calcium carbonate precipitate structures as a function of initial concentrations and injection flow rate. We show that, in some part of the parameter space, the patterns are similar and feature comparable properties indicating that barium and calcium behave similarly in the related flow-controlled precipitation conditions. For other values of parameters though, the precipitate structures are different indicating that the cohesive and microscopic properties of barium versus calcium carbonate are then important in shaping the pattern in flow conditions.

  3. Numberical simulation of the effects of radially injected barium plasma in the ionosphere

    NASA Technical Reports Server (NTRS)

    Swift, D. W.

    1985-01-01

    The morphology of the ion cloud in the radial shaped charge barium injection was studied. The shape of the ion cloud that remains after the explosive products and neutral barium clears away was examined. The ion cloud which has the configuration of a rimless wagon wheel is shown. The major features are the 2.5 km radius black hole in the center of the cloud, the surrounding ring of barium ion and the spokes of barium ionization radiating away from the center. The cloud shows no evolution after it emerges from the neutral debris and it is concluded that it is formed within 5 seconds of the event. A numerical model is used to calculate the motion of ions and electrons subject to the electrostatic and lorenz forces.

  4. Severe acute cholangitis after endoscopic sphincterotomy induced by barium examination: A case report.

    PubMed

    Zhang, Zhen-Hai; Wu, Ya-Guang; Qin, Cheng-Kun; Su, Zhong-Xue; Xu, Jian; Xian, Guo-Zhe; Wu, Shuo-Dong

    2012-10-21

    Endoscopic sphincterotomy (EST) is considered as a possible etiological factor for severe cholangitis. We herein report a case of severe cholangitis after endoscopic sphincterotomy induced by barium examination. An adult male patient presented with epigastric pain was diagnosed as having choledocholithiasis by ultrasonography. EST was performed and the stone was completely cleaned. Barium examination was done 3 d after EST and severe cholangitis appeared 4 h later. The patient was recovered after treated with tienam for 4 d. Barium examination may induce severe cholangitis in patients after EST, although rare, barium examination should be chosen cautiously. Cautions should be also used when EST is performed in patients younger than 50 years to avoid the damage to the sphincter of Oddi.

  5. 21 CFR 201.304 - Tannic acid and barium enema preparations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... added to barium enemas to improve X-ray pictures. Tannic acid is capable of causing diminished liver... use in enemas. Tannic acid for rectal use to enhance X-ray visualization is regarded as a new drug...

  6. The value of the preoperative barium-enema examination in the assessment of pelvic masses

    SciTech Connect

    Gedgaudas, R.K.; Kelvin, F.M.; Thompson, W.M.; Rice, R.P.

    1983-03-01

    The value of the barium-enema examination in the assessment of pelvic masses was studied in 44 patients. Findings from those barium-enema examinations and from pathological specimens from 37 patients who had malignant tumors and seven patients who had endometriosis were retrospectively analyzed to determine if the barium-enema examination is useful in differentiating extrinsic lesions with and without invasion of the colon. None of the 12 patients who had extrinsic lesions had any of the criteria that indicated bowel-wall invasion. These criteria included fixation and serrations of the bowel wall in all patients with invasion, and ulceration and fistulizaton in those patients who had complete transmural invasion. In patients with pelvic masses, the preoperative barium-enema examination may be useful to the surgeon in planning surgery and in preparing the patient for the possibility of partial colectomy or colostomy.

  7. Sponge-associated bacteria mineralize arsenic and barium on intracellular vesicles

    DOE PAGES

    Keren, Ray; Mayzel, Boaz; Lavy, Adi; ...

    2017-02-24

    Arsenic and barium are ubiquitous environmental toxins that accumulate in higher trophic-level organisms. Whereas metazoans have detoxifying organs to cope with toxic metals, sponges lack organs but harbour a symbiotic microbiome performing various functions. Here we examine the potential roles of microorganisms in arsenic and barium cycles in the sponge Theonella swinhoei, known to accumulate high levels of these metals. We show that a single sponge symbiotic bacterium, Entotheonella sp., constitutes the arsenic- and barium-accumulating entity within the host. These bacteria mineralize both arsenic and barium on intracellular vesicles. Our results indicate that Entotheonella sp. may act as a detoxifyingmore » organ for its host.« less

  8. 75 FR 36629 - Barium Chloride From the People's Republic of China: Continuation of Antidumping Duty Order

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-28

    ... China: Final Results of Expedited Third Sunset Review of Antidumping Duty Order, 74 FR 55814 (October 29... the order is barium chloride, a chemical compound having the formulas BaCl 2 or BaCl 2 - 2H 2...

  9. Evaluation of Manganese Phosphate Coatings.

    DTIC Science & Technology

    1984-02-01

    84003 _____________ 4 . TTLE and -bitle)5. TYPE OF REPORT & PERIOD COVERED EVALUATION OF MANGANESE PHOSPHATE COATINGS Final 6. PERFORMING ORG. REPORT...rosion resistance of the Endurion phosphate was significantly superior to the 4 . basic manganese phosphate . Endurion phosphate with a Supplementary...OF CONTENTS Page STATEMENT OF THE PROBLEM 1 BACKGROUND 1 APPROACH TO THE PROBLEM 3 RESULTS 4 CONCLUSIONS 7 TABLES I. Falex Wear Life Test Procedure 8

  10. Barium isotopes in Allende meteorite - Evidence against an extinct superheavy element

    NASA Technical Reports Server (NTRS)

    Lewis, R. S.; Anders, E.; Shimamura, T.; Lugmair, G. W.

    1983-01-01

    Carbon and chromite fractions from the Allende meteorite that contain isotopically anomalous xenon-131 to xenon-136 (carbonaceous chondrite fission or CCF xenon) at up to 5 x 10 to the 11th atoms per gram show no detectable isotopic anomalies in barium-130 to barium-138. This rules out the possibility that the CCF xenon was formed by in situ fission of an extinct superheavy element. Apparently the CCF xenon and its carbonaceous carrier are relics from stellar nucleosynthesis.

  11. Calculations of energy levels and lifetimes of low-lying states of barium and radium

    SciTech Connect

    Dzuba, V. A.; Ginges, J. S. M.

    2006-03-15

    We use the configuration-interaction method and many-body perturbation theory to perform accurate calculations of energy levels, transition amplitudes, and lifetimes of low-lying states of barium and radium. Calculations for radium are needed for the planning of measurements of parity- and time-invariance-violating effects which are strongly enhanced in this atom. Calculations for barium are used to control the accuracy of the calculations.

  12. Elevated Z line: a new sign of Barrett's esophagus on double-contrast barium esophagograms.

    PubMed

    Levine, Marc S; Ahmad, Nuzhat A; Rubesin, Stephen E

    2015-01-01

    We describe an elevated Z line as a new radiographic sign of Barrett's esophagus characterized by a transversely oriented, zigzagging, barium-etched line extending completely across the circumference of the midesophagus. An elevated Z line is rarely seen in other patients, so this finding should be highly suggestive of Barrett's esophagus on double-contrast barium esophagograms. If the patient is a potential candidate for surveillance, endoscopy and biopsy should be performed to confirm the presence of Barrett's esophagus.

  13. Comparison of the reflectance characteristics of polytetrafluoroethylene and barium sulfate paints

    NASA Technical Reports Server (NTRS)

    Butner, C. L.; Schutt, J. B.; Shai, M. C.

    1984-01-01

    Preliminary results are presented of the directional reflectance measurements taken on two tetrafluorethylene (TFE) paints formulated with silicone binders. Both paints are found to be more Lambertian than barium sulfate paint and pressed powder, although the pigment to binder ratios for barium sulfate and TFE paints are about 133 and 3.3 to 1, respectively. The TFE paints exhibit total visible reflectances above 90 percent and offer surfaces that are not significantly affected by water.

  14. Role of Barium Swallow in Diagnosing Clinically Significant Anastomotic Leak following Esophagectomy

    PubMed Central

    Roh, Simon; Iannettoni, Mark D.; Keech, John C.; Bashir, Mohammad; Gruber, Peter J.; Parekh, Kalpaj R.

    2016-01-01

    Background Barium swallow is performed following esophagectomy to evaluate the anastomosis for detection of leaks and to assess the emptying of the gastric conduit. The aim of this study was to evaluate the reliability of the barium swallow study in diagnosing anastomotic leaks following esophagectomy. Methods Patients who underwent esophagectomy from January 2000 to December 2013 at our institution were investigated. Barium swallow was routinely done between days 5–7 to detect a leak. These results were compared to clinically determined leaks (defined by neck wound infection requiring jejunal feeds and or parenteral nutrition) during the postoperative period. The sensitivity and specificity of barium swallow in diagnosing clinically significant anastomotic leaks was determined. Results A total of 395 esophagectomies were performed (mean age, 62.2 years). The indications for the esophagectomy were as follows: malignancy (n=320), high-grade dysplasia (n=14), perforation (n=27), benign stricture (n=7), achalasia (n=16), and other (n=11). A variety of techniques were used including transhiatal (n=351), McKeown (n=35), and Ivor Lewis (n=9) esophagectomies. Operative mortality was 2.8% (n=11). Three hundred and sixty-eight patients (93%) underwent barium swallow study after esophagectomy. Clinically significant anastomotic leak was identified in 36 patients (9.8%). Barium swallow was able to detect only 13/36 clinically significant leaks. The sensitivity of the swallow in diagnosing a leak was 36% and specificity was 97%. The positive and negative predictive values of barium swallow study in detecting leaks were 59% and 93%, respectively. Conclusion Barium swallow is an insensitive but specific test for detecting leaks at the cervical anastomotic site after esophagectomy. PMID:27066433

  15. Kubelka-Munk optical properties of a barium sulfate white reflectance standard.

    PubMed

    Patterson, E M; Shelden, C E; Stockton, B H

    1977-03-01

    We have measured the Kubelka-Munk scattering and absorption coefficients for a barium sulfate white reflectance standard. These measurements have been based on measurements of the absolute reflectance for the particular barium sulfate samples whose scattering and absorption coefficients were measured. This method gives results that are different from earlier measurements; the differences are significant for measurements of the optical properties of atmospheric aerosols.

  16. Barium swallow study in routine clinical practice: a prospective study in patients with chronic cough*,**

    PubMed Central

    Nin, Carlos Shuler; Marchiori, Edson; Irion, Klaus Loureiro; Paludo, Artur de Oliveira; Alves, Giordano Rafael Tronco; Hochhegger, Daniela Reis; Hochhegger, Bruno

    2013-01-01

    OBJECTIVE: To assess the routine use of barium swallow study in patients with chronic cough. METHODS: Between October of 2011 and March of 2012, 95 consecutive patients submitted to chest X-ray due to chronic cough (duration > 8 weeks) were included in the study. For study purposes, additional images were obtained immediately after the oral administration of 5 mL of a 5% barium sulfate suspension. Two radiologists systematically evaluated all of the images in order to identify any pathological changes. Fisher's exact test and the chi-square test for categorical data were used in the comparisons. RESULTS: The images taken immediately after barium swallow revealed significant pathological conditions that were potentially related to chronic cough in 12 (12.6%) of the 95 patients. These conditions, which included diaphragmatic hiatal hernia, esophageal neoplasm, achalasia, esophageal diverticulum, and abnormal esophageal dilatation, were not detected on the images taken without contrast. After appropriate treatment, the symptoms disappeared in 11 (91.6%) of the patients, whereas the treatment was ineffective in 1 (8.4%). We observed no complications related to barium swallow, such as contrast aspiration. CONCLUSIONS: Barium swallow improved the detection of significant radiographic findings related to chronic cough in 11.5% of patients. These initial findings suggest that the routine use of barium swallow can significantly increase the sensitivity of chest X-rays in the detection of chronic cough-related etiologies. PMID:24473762

  17. Technical development: CT colonography without cathartic cleansing and with barium as the sole tagging agent

    NASA Astrophysics Data System (ADS)

    Lefere, Philippe; Gryspeerdt, Stefaan; Baekelandt, Marc; Van Holsbeeck, Bartel

    2004-04-01

    The purpose of this study was to perform CT colonography (CTC) without cathartic colon cleansing. Four groups of 3 patients were prepared the day before CTC with a dedicated low residue diet, a hydration control allowing 2 liters of fluid intake and barium as tagging agent. Four different barium regimens were investigated. Groups 1 and 3 ingested barium over 1 day at different concentrations and groups 2 and 4 over 2 days. The barium volume to drink the day before CTC was 750 ml in groups 1 and 2 and 50 ml in groups 3 and 4. The fluid, density measurements of the fecal residue and tagging efficacy were evaluated. All fecal residue with densities >= 150 H.U. was electronically labeled. Per segment a visual labeling score (0, 25, 50, 75, 100%) was performed. The fluid was evaluated according to its proportion to the maximum anteroposterior diameter of the colonic segment where it was detected. No significant differences in densities of tagged residue were detected. The visual labeling scores varied between 90 and 100% in all segments. There were 6 fluid levels: 5 covering < 10% and one covering 50% of the colonic lumen. The lowest density of the fluid was 360 H.U. In this preliminary study we could conclude that CTC without cathartic cleansing and with barium produced efficient labeling of fecal residue. The barium intake could be reduced to one day and to 50 ml.

  18. Comparison of Calcium and Barium Microcapsules as Scaffolds in the Development of Artificial Dermal Papillae

    PubMed Central

    Liu, Yang; Lin, Changmin; Zeng, Yang; Li, Haihong; Cai, Bozhi; Huang, Keng; Yuan, Yanping; Li, Yu

    2016-01-01

    This study aimed to develop and evaluate barium and calcium microcapsules as candidates for scaffolding in artificial dermal papilla. Dermal papilla cells (DPCs) were isolated and cultured by one-step collagenase treatment. The DPC-Ba and DPC-Ca microcapsules were prepared by using a specially designed, high-voltage, electric-field droplet generator. Selected microcapsules were assessed for long-term inductive properties with xenotransplantation into Sprague-Dawley rat ears. Both barium and calcium microcapsules maintained xenogenic dermal papilla cells in an immunoisolated environment and induced the formation of hair follicle structures. Calcium microcapsules showed better biocompatibility, permeability, and cell viability in comparison with barium microcapsules. Before 18 weeks, calcium microcapsules gathered together, with no substantial immune response. After 32 weeks, some microcapsules were near inflammatory cells and wrapped with fiber. A few large hair follicles were found. Control samples showed no marked changes at the implantation site. Barium microcapsules were superior to calcium microcapsules in structural and mechanical stability. The cells encapsulated in hydrogel barium microcapsules exhibited higher short-term viability. This study established a model to culture DPCs in 3D culture conditions. Barium microcapsules may be useful in short-term transplantation study. Calcium microcapsules may provide an effective scaffold for the development of artificial dermal papilla. PMID:27123456

  19. Comparison of Calcium and Barium Microcapsules as Scaffolds in the Development of Artificial Dermal Papillae.

    PubMed

    Liu, Yang; Lin, Changmin; Zeng, Yang; Li, Haihong; Cai, Bozhi; Huang, Keng; Yuan, Yanping; Li, Yu

    2016-01-01

    This study aimed to develop and evaluate barium and calcium microcapsules as candidates for scaffolding in artificial dermal papilla. Dermal papilla cells (DPCs) were isolated and cultured by one-step collagenase treatment. The DPC-Ba and DPC-Ca microcapsules were prepared by using a specially designed, high-voltage, electric-field droplet generator. Selected microcapsules were assessed for long-term inductive properties with xenotransplantation into Sprague-Dawley rat ears. Both barium and calcium microcapsules maintained xenogenic dermal papilla cells in an immunoisolated environment and induced the formation of hair follicle structures. Calcium microcapsules showed better biocompatibility, permeability, and cell viability in comparison with barium microcapsules. Before 18 weeks, calcium microcapsules gathered together, with no substantial immune response. After 32 weeks, some microcapsules were near inflammatory cells and wrapped with fiber. A few large hair follicles were found. Control samples showed no marked changes at the implantation site. Barium microcapsules were superior to calcium microcapsules in structural and mechanical stability. The cells encapsulated in hydrogel barium microcapsules exhibited higher short-term viability. This study established a model to culture DPCs in 3D culture conditions. Barium microcapsules may be useful in short-term transplantation study. Calcium microcapsules may provide an effective scaffold for the development of artificial dermal papilla.

  20. Thermal conversions of the yttrium-barium-copper salt of carboxylated cellulose and the synthesis of yttrium barium cuprate from it

    SciTech Connect

    Kaputskii, F.N.; Bashmakov, I.A.; Novikov, V.P.

    1994-09-20

    Thermal solid-phase conversions of the yttrium-barium-copper salt of tricarboxycellulose (TCC) with a 1-2-3 cation stoichiometry, respectively, have been considered. Yttrium barium cuprate is the end product of the thermal treatment of the triple salt. According to the data of X-ray analysis the onset of 1-2-3 phase formation is noticeable at 750-800{degrees}C. The temperature 875{degrees}C (with a duration of heating of 12 h) is sufficient for practically complete conversion of the Y-Ba-Cu salt of TCC into YBa{sub 2}Cu{sub 3}O{sub 7-{delta}}.

  1. Calcium Phosphates and Human Beings

    NASA Astrophysics Data System (ADS)

    Dorozhkin, Sergey V.

    2006-05-01

    This article describes the general importance of calcium phosphates for human beings. The basic information on the structure and chemical properties of the biologically relevant calcium phosphates is summarized. Basic facts on the natural occurrence and the industrial use of natural calcium phosphates are discussed. Fundamental details on the presence of calcium phosphates in major calcified tissues (bones and teeth) of humans and mammals, as well as on biomaterials made of calcium phosphates are discussed. The article will be of value for chemistry teachers for expansion of their general background and point the students' attention to the rapidly growing topic of bone-substituting biomaterials.

  2. 21 CFR 184.1434 - Magnesium phosphate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Magnesium phosphate. 184.1434 Section 184.1434 Food... Specific Substances Affirmed as GRAS § 184.1434 Magnesium phosphate. (a) Magnesium phosphate includes both magnesium phosphate, dibasic, and magnesium phosphate, tribasic. Magnesium phosphate, dibasic (MgHPO4·3H2O...

  3. 21 CFR 184.1434 - Magnesium phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Magnesium phosphate. 184.1434 Section 184.1434... GRAS § 184.1434 Magnesium phosphate. (a) Magnesium phosphate includes both magnesium phosphate, dibasic, and magnesium phosphate, tribasic. Magnesium phosphate, dibasic (MgHPO4·3H2O, CAS Reg. No. 7782-0975...

  4. 21 CFR 184.1434 - Magnesium phosphate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Magnesium phosphate. 184.1434 Section 184.1434... Listing of Specific Substances Affirmed as GRAS § 184.1434 Magnesium phosphate. (a) Magnesium phosphate includes both magnesium phosphate, dibasic, and magnesium phosphate, tribasic. Magnesium phosphate, dibasic...

  5. 21 CFR 184.1434 - Magnesium phosphate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Magnesium phosphate. 184.1434 Section 184.1434... Listing of Specific Substances Affirmed as GRAS § 184.1434 Magnesium phosphate. (a) Magnesium phosphate includes both magnesium phosphate, dibasic, and magnesium phosphate, tribasic. Magnesium phosphate, dibasic...

  6. 21 CFR 184.1434 - Magnesium phosphate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Magnesium phosphate. 184.1434 Section 184.1434... Listing of Specific Substances Affirmed as GRAS § 184.1434 Magnesium phosphate. (a) Magnesium phosphate includes both magnesium phosphate, dibasic, and magnesium phosphate, tribasic. Magnesium phosphate, dibasic...

  7. Defect Chemistry and Microstructure of Complex Perovskite Barium Zinc Niobate

    NASA Astrophysics Data System (ADS)

    Peng, Ping

    1991-02-01

    This dissertation presents a systematic study of the characterization of the phase transitions, microstructures, defects and transport properties of undoped and doped complex perovskite barium zinc niobate (BZN). Complex perovskite BZN is a paraelectric material while its parent material barium titanate is ferroelectric. With codoping of (Zn + 2Nb) into Ti site, BaTiO_3 shows three distinguished features. First, the Curie temperature is lowered; second, the three phase transitions (cubic-tetragonal-orthorhombic-rhombohedral) coalesce; and lastly, the transition becomes diffuse showing a typical 2nd order phase transition compared with 1st order in undoped BaTiO_3. Complex microchemical ordering is another characteristic of BZN. Stoichiometric BZN shows a mixture of two types of ordering schemes. 1:1, 1:2 ordered microdomains and the disordered matrix co-exist. The 1:1 type ordering involves an internal charge imbalance which inhibits the growth of 1:1 type of ordered microdomains. The 1:2 type ordering is consistent with the chemical composition of BZN. These ordering patterns can be modified by either adjustment of the Zn/Nb ratio or by doping. The defect structure of the stoichiometric BZN is closely related to that of BaTiO_3. Stoichiometric BZN is an insulator with wide band gap (~ 3.70 eV). Undoped BZN has a high oxygen vacancy concentration which comes from three possible sources, such as unavoidable acceptor impurities, due to their natural abundance, Zn/Nb ratio uncertainty due to processing limitations, and high temperature ZnO loss due to sintering process. The oxygen vacancy concentration for undoped BZN lays in the neighborhood of 1500 ppm (atm.). The compensation defects for various dopants have also been identified. Both electrons and holes conduct by a small polaron mechanism. Various thermodynamic parameters, such as enthalpies of oxidation and reduction, mass action constants for intrinsic electronic disorder, oxidation and reduction have been

  8. Supramolecular curcumin-barium prodrugs for formulating with ceramic particles.

    PubMed

    Kamalasanan, Kaladhar; Anupriya; Deepa, M K; Sharma, Chandra P

    2014-10-01

    A simple and stable curcumin-ceramic combined formulation was developed with an aim to improve curcumin stability and release profile in the presence of reactive ceramic particles for potential dental and orthopedic applications. For that, curcumin was complexed with barium (Ba(2+)) to prepare curcumin-barium (BaCur) complex. Upon removal of the unbound curcumin and Ba(2+) by dialysis, a water-soluble BaCur complex was obtained. The complex was showing [M+1](+) peak at 10,000-20,000 with multiple fractionation peaks of MALDI-TOF-MS studies, showed that the complex was a supramolecular multimer. The (1)H NMR and FTIR studies revealed that, divalent Ba(2+) interacted predominantly through di-phenolic groups of curcumin to form an end-to-end complex resulted in supramolecular multimer. The overall crystallinity of the BaCur was lower than curcumin as per XRD analysis. The complexation of Ba(2+) to curcumin did not degrade curcumin as per HPLC studies. The fluorescence spectrum was blue shifted upon Ba(2+) complexation with curcumin. Monodisperse nanoparticles with size less than 200dnm was formed, out of the supramolecular complex upon dialysis, as per DLS, and upon loading into pluronic micelles the size was remaining in similar order of magnitude as per DLS and AFM studies. Stability of the curcumin was improved greater than 50% after complexation with Ba(2+) as per UV/Vis spectroscopy. Loading of the supramloecular nanoparticles into pluronic micelles had further improved the stability of curcumin to approx. 70% in water. These BaCur supramolecule nanoparticles can be considered as a new class of prodrugs with improved solubility and stability. Subsequently, ceramic nanoparticles with varying chemical composition were prepared for changing the material surface reactivity in terms of the increase in, degradability, surface pH and protein adsorption. Further, these ceramic particles were combined with curcumin prodrug formulations and optimized the curcumin release

  9. The first barium tin(II) bromide fluoride

    NASA Astrophysics Data System (ADS)

    Dénès, Georges; Merazig, Hocine; Muntasar, Abdualhafeed; Porterfield, Robyn

    2014-04-01

    In an effort to prepare barium tin(II) bromide fluorides for the first time, possibly similar to the chloride fluorides obtained earlier in our laboratory, precipitation reactions were carried out by mixing aqueous solutions of SnF2 and of BaBr2.2H2O. In contrast with the chloride fluoride system, a single powdered phase was obtained throughout the SnF2 - BaBr2 system, with the yield being maximum at X ≈ 0.25, where X is the molar fraction of barium bromide in the reaction mixture. Phase identification with the JCPDS database failed to produce a match, confirming that a new phase had been produced. The exact chemical composition of the new compound has not been obtained yet. Based on the X value for the maximum yield, the Sn/Ba ratio is likely to be 3/1 or 2/1. The Mössbauer spectrum at ambient conditions shows that bonding to tin(II) is covalent, therefore with the tin lone pair being stereoactive. The Mössbauer parameters ( δ = 3.68 mm/s, Δ = 0.99 mm/s) are similar to those of SnBrF and of Sn2BrF5, thereby showing that tin is bonded to both fluorine and bromine. The larger isomer shift and lower quadrupole splitting than in tin(II) fluorides show that the stereoactivity of the tin lone pair is lower than in the fluorides. The Mössbauer parameters fit well the linear correlation of the quadrupole splitting versus the isomer shift" that has been shown to be present in other series of tin(II) compounds. The linear decrease on this correlation shows that the contribution of non-spherical orbitals ( p and d) to the lone pair is a much larger contributor to the quadrupole splitting than lattice distortions. The structure is likely made of Ba2+ cations and tin(II) fluoride bromide polyatomic anions, with covalent bonding withinthe anions.

  10. Biomediated continuous release phosphate fertilizer

    DOEpatents

    Goldstein, A.H.; Rogers, R.D.

    1999-06-15

    A composition is disclosed for providing phosphate fertilizer to the root zone of plants. The composition comprises a microorganism capable of producing and secreting a solubilization agent, a carbon source for providing raw material for the microorganism to convert into the solubilization agent, and rock phosphate ore for providing a source of insoluble phosphate that is solubilized by the solubilization agent and released as soluble phosphate. The composition is provided in a physical form, such as a granule, that retains the microorganism, carbon source, and rock phosphate ore, but permits water and soluble phosphate to diffuse into the soil. A method of using the composition for providing phosphate fertilizer to plants is also disclosed. 13 figs.

  11. Biomediated continuous release phosphate fertilizer

    SciTech Connect

    Goldstein, Alan H.; Rogers, Robert D.

    1999-01-01

    A composition is disclosed for providing phosphate fertilizer to the root zone of plants. The composition comprises a microorganism capable of producing and secreting a solubilization agent, a carbon source for providing raw material for the microorganism to convert into the solubilization agent, and rock phosphate ore for providing a source of insoluble phosphate that is solubilized by the solubilization agent and released as soluble phosphate. The composition is provided in a physical form, such as a granule, that retains the microorganism, carbon source, and rock phosphate ore, but permits water and soluble phosphate to diffuse into the soil. A method of using the composition for providing phosphate fertilizer to plants is also disclosed.

  12. Renal phosphate handling: Physiology

    PubMed Central

    Prasad, Narayan; Bhadauria, Dharmendra

    2013-01-01

    Phosphorus is a common anion. It plays an important role in energy generation. Renal phosphate handling is regulated by three organs parathyroid, kidney and bone through feedback loops. These counter regulatory loops also regulate intestinal absorption and thus maintain serum phosphorus concentration in physiologic range. The parathyroid hormone, vitamin D, Fibrogenic growth factor 23 (FGF23) and klotho coreceptor are the key regulators of phosphorus balance in body. PMID:23961477

  13. Active experiments in space in conjunction with Skylab. [barium plasma injection experiment and magnetic storm of March 7, 1972

    NASA Technical Reports Server (NTRS)

    Wescott, E. M.

    1974-01-01

    Two papers are presented which relate to the Skylab barium shaped charge experiments. The first describes the L=6.6 OOSIK barium plasma injection experiment and magnetic storm of March 7, 1972. Rocket payload, instrumentation, data reduction methods, geophysical environment at the time of the experiment, and results are given. The second paper presents the observation of an auroral Birkeland current which developed from the distortion of a barium plasma jet during the above experiment.

  14. Barium from a mini r-process in supernovae

    NASA Technical Reports Server (NTRS)

    Heymann, D.

    1983-01-01

    McCulloch and Wasserburg (1978) have reported nonlinear isotopic anomalies in barium for two Ca-Al-rich inclusions of the Allende carbonaceous chondrite, known as EK-1-4-1 and C-1. In an attempt to account for these anomalies, it has been proposed that Ba from an r-process of nucleosynthesis, containing Ba-135 and Ba-137, was injected into the primeval color system but was not totally homogenized. Questions arise in connection with the relations of Xe isotopes in carbonaceous chondrites. This has prompted Heymann and Dziczkaniec (1979, 1980, 1981) to study the formation of r-Xe, r-Kr, and r-Te by the mini r-process which is thought to occur in the O, Ne-rich shells of Type II supernovae. Lee et al. (1979) have studied the formation of r-Ba, r-Nd, and r-Sm by the same process. Certain differences regarding the approaches used by Lee et al. and by Heymann and Dziczkaniec make it necessary to restudy the work of Lee et al. Attention is given to the survival probabilities of nuclear species of interest, taking into accounts the elements Cs, Ba, I, and Xe.

  15. Review on dielectric properties of rare earth doped barium titanate

    SciTech Connect

    Ismail, Fatin Adila; Osman, Rozana Aina Maulat; Idris, Mohd Sobri

    2016-07-19

    Rare earth doped Barium Titanate (BaTiO{sub 3}) were studied due to high permittivity, excellent electrical properties and have wide usage in various applications. This paper reviewed on the electrical properties of RE doped BaTiO{sub 3} (RE: Lanthanum (La), Erbium (Er), Samarium (Sm), Neodymium (Nd), Cerium (Ce)), processing method, phase transition occurred and solid solution range for complete study. Most of the RE doped BaTiO{sub 3} downshifted the Curie temperature (T{sub C}). Transition temperature also known as Curie temperature, T{sub C} where the ceramics had a transition from ferroelectric to a paraelectric phase. In this review, the dielectric constant of La-doped BaTiO{sub 3}, Er-doped BaTiO{sub 3}, Sm-doped BaTiO{sub 3}, Nd-doped BaTiO{sub 3} and Ce-doped BaTiO{sub 3} had been proved to increase and the transition temperature or also known as T{sub C} also lowered down to room temperature as for all the RE doped BaTiO{sub 3} except for Er-doped BaTiO{sub 3}.

  16. Properties of barium strontium titanate at millimeter wave frequencies

    SciTech Connect

    Osman, Nurul; Free, Charles

    2015-04-24

    The trend towards using higher millimetre-wave frequencies for communication systems has created a need for accurate characterization of materials to be used at these frequencies. Barium Strontium Titanate (BST) is a ferroelectric material whose permittivity is known to change as a function of applied electric field and have found varieties of application in electronic and communication field. In this work, new data on the properties of BST characterize using the free space technique at frequencies between 145 GHz and 155 GHz for both thick film and bulk samples are presented. The measurement data provided useful information on effective permittivity and loss tangent for all the BST samples. Data on the material transmission, reflection properties as well as loss will also be presented. The outcome of the work shows through practical measurement, that BST has a high permittivity with moderate losses and the results also shows that BST has suitable properties to be used as RAM for high frequency application.

  17. Hydrogen diffusion in lead zirconate titanate and barium titanate

    NASA Astrophysics Data System (ADS)

    Alvine, K. J.; Vijayakumar, M.; Bowden, M. E.; Schemer-Kohrn, A. L.; Pitman, S. G.

    2012-08-01

    Hydrogen is a potential clean-burning, next-generation fuel for vehicle and stationary power. Unfortunately, hydrogen is also well known to have serious materials compatibility issues in metals, polymers, and ceramics. Piezoelectric actuator materials proposed for low-cost, high efficiency high-pressure hydrogen internal combustion engines (HICE) are known to degrade rapidly in hydrogen. This limits their potential use and poses challenges for HICE. Hydrogen-induced degradation of piezoelectrics is also an issue for low-pressure hydrogen passivation in ferroelectric random access memory. Currently, there is a lack of data in the literature on hydrogen species diffusion in piezoelectrics in the temperature range appropriate for the HICE as charged via a gaseous route. We present 1HNMR quantification of the local hydrogen species diffusion within lead zirconate titanate and barium titanate on samples charged by exposure to high-pressure gaseous hydrogen ˜32 MPa. Results are discussed in context of theoretically predicted interstitial hydrogen lattice sites and aqueous charging experiments from existing literature.

  18. Sintering and foaming of barium silicate glass powder compacts

    NASA Astrophysics Data System (ADS)

    Mueller, Ralf; Reinsch, Stefan; Agea-Blanco, Boris

    2016-10-01

    The manufacture of sintered glasses and glass-ceramics, glass matrix composites and glass-bounded ceramics or pastes is often affected by gas bubble formation. Against this background, we studied sintering and foaming of barium silicate glass powders used as SOFC sealants using different powder milling procedures. Sintering was measured by means of heating microscopy backed up by XPD, DTA, Vacuum Hot Extraction (VHE) and optical and electron microscopy. Foaming increased significantly as milling progressed. For moderately milled glass powders, subsequent storage in air could also promote foaming. Although the powder compacts were uniaxially pressed and sintered in air, the milling atmosphere sig¬ni¬ficantly affected foaming. The strength of this effect increased in the order Ar ? N2 < air < CO2. Conformingly, VHE studies revealed that the pores of foamed samples predominantly encapsulated CO2, even for powders milled in Ar and N2. Results of this study thus indicate that foaming is caused by carbonaceous species trapped on the glass powder surface. Foaming could be substantially reduced by milling in water and 10 wt% HCl.

  19. Communication: Barium ions and helium nanodroplets: Solvation and desolvation

    SciTech Connect

    Zhang Xiaohang; Drabbels, Marcel

    2012-08-07

    The solvation of Ba{sup +} ions created by the photoionization of barium atoms located on the surface of helium nanodroplets has been investigated. The excitation spectra corresponding to the 6p {sup 2}P{sub 1/2} Leftwards-Arrow 6s {sup 2}S{sub 1/2} and 6p {sup 2}P{sub 3/2} Leftwards-Arrow 6s {sup 2}S{sub 1/2} transitions of Ba{sup +} are found to be identical to those recorded in bulk He II [H. J. Reyher, H. Bauer, C. Huber, R. Mayer, A. Schafer, and A. Winnacker, Phys. Lett. A 115, 238 (1986)], indicating that the ions formed at the surface of the helium droplets become fully solvated by the helium. Time-of-flight mass spectra suggest that following the excitation of the solvated Ba{sup +} ions, these are being ejected from the helium droplets either as bare Ba{sup +} ions or as small Ba{sup +}He{sub n} (n < 20) complexes.

  20. Beta Decay Studies of Short Lived Barium Isotopes

    NASA Astrophysics Data System (ADS)

    Bendall, Charles Skipwith

    The half-lives and relative intensities of several short lived neutron rich isotopes, with atomic numbers between 54 and 57, produced in the spontaneous fission of californium-252 were determined. This was accomplished from the study of the time variation of the K X-ray yields of these isotopes. A transport system which allowed us to study isotopes with half-lives less than 10 seconds was developed. Mass assignments were made by comparing the experimental values of the half-lives with known values. A beta K X-ray coincidence technique was used to obtain the barium beta spectrum in coincidence with lanthanum K X -rays. A Kurie plot was performed on the spectrum to determine the beta groups. The probable origin of each beta group was determined through a comparison of the relative intensities of the isotopes and beta groups. Four beta groups probably from the decay of Ba-145 were revealed. The end point energies of these beta groups are 3870 (+OR-) 432 keV, 2772 (+OR-) 112 keV, 1894 (+OR-) 58 keV, and 746 (+OR-) 38 keV. The three lowest energy groups have not been observed before.

  1. Two new barium sulfonates with pillared layered structures

    NASA Astrophysics Data System (ADS)

    Yang, Jin; Li, Li; Ma, Jian-Fang; Liu, Ying-Ying; Ma, Ji-Cheng

    2006-05-01

    The reactions of BaCl 2·2H 2O with NaHL a and K 3L b (H 2L a=4-hydroxybenzenesulfonic acid, H 3L b=4-hydroxy-5-nitro-1,3-benzenedisulfonic acid) gave two pillared layered coordination polymers: Ba(HL a)(Cl) 1 and KBaL b(H 2O) 32, respectively. The crystal structures were determined by X-ray diffraction method and refined by full-matrix least-squares methods to R=0.0509 and wR=0.1216 using 1455 reflections with I>2 σ( I) for 1; and R=0.0288 and wR=0.0727 using 2661 reflections with I>2 σ( I) for 2. The interesting feature of compound 1 is the coordination actions of chloride anions, which help to form the polymeric layers by bridging barium cations. In compound 2 the Lb3- anion acts as an unusual dodecadente ligand to form a coordination polymer with pillared layered structure.

  2. Two new barium sulfonates with pillared layered structures

    NASA Astrophysics Data System (ADS)

    Yang, Jin; Li, Li; Ma, Jian-Fang; Liu, Ying-Ying; Ma, Ji-Cheng

    2006-08-01

    The reactions of BaCl 2·2H 2O with NaHL a and K 3L b (H 2L a=4-hydroxybenzenesulfonic acid, H 3L b=4-hydroxy-5-nitro-1,3-benzenedisulfonic acid) gave two pillared layered coordination polymers: Ba(HL a)(Cl) 1 and KBaL b(H 2O) 32, respectively. The crystal structures were determined by X-ray diffraction method and refined by full-matrix least-squares methods to R=0.0509 and wR=0.1216 using 1455 reflections with I>2 σ( I) for 1; and R=0.0288 and wR=0.0727 using 2661 reflections with I>2 σ( I) for 2. The interesting feature of compound 1 is the coordination actions of chloride anions, which help to form the polymeric layers by bridging barium cations. In compound 2 the Lb3- anion acts as an unusual dodecadente ligand to form a coordination polymer with pillared layered structure.

  3. Enhanced photocatalytic hydrogen generation from barium tantalate composites.

    PubMed

    Marschall, Roland; Soldat, Julia; Busser, G Wilma; Wark, Michael

    2013-04-01

    (111)-layered Ba5Ta4O15 photocatalysts were synthesised by a solid state reaction route and a citrate synthesis route, and their structural and electronic properties were investigated. After citrate route preparation, the presence of a second phase, namely Ba3Ta5O15, was determined by X-ray powder diffraction and absorption spectroscopy. The existence of this phase had a profound effect on the photocatalytic activity of this Ba5Ta4O15/Ba3Ta5O15 composite in comparison to the pure Ba5Ta4O15 materials. The photocatalytic performance of the barium tantalates was evaluated by investigating the capability in ˙OH radical formation and hydrogen generation. Strongly increased hydrogen evolution rates for the Ba5Ta4O15/Ba3Ta5O15 composite, up to 160% higher than for the pure Ba5Ta4O15, were determined, and only very small amounts of Rh co-catalyst, deposited on the photocatalysts by stepwise reductive photo-deposition, were needed to achieve these results.

  4. Dielectric and Impedance Spectroscopy of Barium Bismuth Vanadate Ferroelectrics

    NASA Astrophysics Data System (ADS)

    Sutar, B. C.; Choudhary, R. N. P.; Das, Piyush R.

    2014-07-01

    Structural, micro-structural and electrical properties of barium bismuth vanadate Ba(Bi0.5V0.5)O3 ceramics were investigated. X-ray diffraction (XRD) analysis of the prepared material confirmed the formation of the compound with monoclinic crystal system. Scanning electron microscopy (SEM) of the compound exhibits well-defined grains that are uniformly distributed throughout the surface of the sample. Dielectric properties of the compound were studied as a function of temperature at different frequencies. An observation of dielectric anomaly at 295 °C is due to ferroelectric phase transition that was later confirmed by the appearance of hysteresis loop. Detailed studies of complex impedance spectroscopy have provided a better understanding of the relaxation process and correlations between the microstructure-electrical properties of the materials. The nature of frequency dependence of ac conductivity obeys the Debye power law. The dc conductivity, calculated from the ac conductivity spectrum, shows the negative temperature coefficient of resistance behavior similar to that of a semiconductor.

  5. Review on dielectric properties of rare earth doped barium titanate

    NASA Astrophysics Data System (ADS)

    Ismail, Fatin Adila; Osman, Rozana Aina Maulat; Idris, Mohd Sobri

    2016-07-01

    Rare earth doped Barium Titanate (BaTiO3) were studied due to high permittivity, excellent electrical properties and have wide usage in various applications. This paper reviewed on the electrical properties of RE doped BaTiO3 (RE: Lanthanum (La), Erbium (Er), Samarium (Sm), Neodymium (Nd), Cerium (Ce)), processing method, phase transition occurred and solid solution range for complete study. Most of the RE doped BaTiO3 downshifted the Curie temperature (TC). Transition temperature also known as Curie temperature, TC where the ceramics had a transition from ferroelectric to a paraelectric phase. In this review, the dielectric constant of La-doped BaTiO3, Er-doped BaTiO3, Sm-doped BaTiO3, Nd-doped BaTiO3 and Ce-doped BaTiO3 had been proved to increase and the transition temperature or also known as TC also lowered down to room temperature as for all the RE doped BaTiO3 except for Er-doped BaTiO3.

  6. The chemical composition of the mild barium star HD 202109

    NASA Astrophysics Data System (ADS)

    Yushchenko, A. V.; Gopka, V. F.; Kim, C.; Liang, Y. C.; Musaev, F. A.; Galazutdinov, G. A.

    2004-01-01

    We present chemical abundances of the mild barium star HD 202109 (\\zeta Cyg) determined from the analysis of a spectrum obtained by using the 2-m telescope at the Peak Terskol Observatory and a high-resolution spectrometer with R=80 000, signal to noise ratio >100. We also present the atmospheric parameters of the star determined using various methods including iron-line abundance analysis. For line identifications, we use whole-range synthetic spectra computed from Kurucz's database and the latest lists of spectral lines. Among the determined abundances of 51 elements, those of P, S, K, Cu, Zn, Ge, Rb, Sr, Nb, Mo, Ru, Rh, Pd, In, Sm, Gd, Tb, Dy, Er, Tm, Hf, Os, Ir, Pt, Tl, and Pb were not investigated previously. Assuming that the overabundance pattern of Ba stars is due to binary accretion, the observed abundance pattern of the neutron-capture process elements in HD 202109 can be explained by combining the AGB star nucleosynthesis and the wind accretion scenario. Based on observations obtained at the 2-m telescope of Peak Terskol observatory near Mt. Elbrus, Northern Caucasus, Russia - International Center for Astronomical, Medical and Ecological Research (ICAMER), Ukraine & Russia.

  7. Barium oxide, calcium oxide, magnesia, and alkali oxide free glass

    DOEpatents

    Lu, Peizhen Kathy; Mahapatra, Manoj Kumar

    2013-09-24

    A glass composition consisting essentially of about 10-45 mole percent of SrO; about 35-75 mole percent SiO.sub.2; one or more compounds from the group of compounds consisting of La.sub.2O.sub.3, Al.sub.2O.sub.3, B.sub.2O.sub.3, and Ni; the La.sub.2O.sub.3 less than about 20 mole percent; the Al.sub.2O.sub.3 less than about 25 mole percent; the B.sub.2O.sub.3 less than about 15 mole percent; and the Ni less than about 5 mole percent. Preferably, the glass is substantially free of barium oxide, calcium oxide, magnesia, and alkali oxide. Preferably, the glass is used as a seal in a solid oxide fuel/electrolyzer cell (SOFC) stack. The SOFC stack comprises a plurality of SOFCs connected by one or more interconnect and manifold materials and sealed by the glass. Preferably, each SOFC comprises an anode, a cathode, and a solid electrolyte.

  8. Exchange bias in barium ferrite/magnetite nanocomposites

    NASA Astrophysics Data System (ADS)

    Molaei, M. J.; Ataie, A.; Raygan, S.; Picken, S. J.

    2017-06-01

    Exchange bias which accompanies a magnetic hysteresis loop shift along field axis or increase in coercivity, occurs due to exchange interactions between ferromagnetic (FM) and antiferromagnetic (AFM) or in ferrimagnetic nanoparticles/nanolayers systems. Mixture of barium ferrite (BaFe12O19) and graphite was mechanically milled for different times. Phase analysis, particles morphology, magnetic properties at room temperature and magnetic properties after field cooling at 4 k were measured via XRD, HRTEM, VSM and SQUID, respectively. A nanocomposite of BaFe12O19/Fe3O4 forms after 20 and 40 h of milling. HRTEM images revealed that the nanocomposite consists of crystallites of both phases in intimate contact with crystallite sizes below 20 nm after 20 h milling. Field cooling of the 20- and 40-h milled samples up to 4 k resulted in exchange bias phenomenon. The shift in hysteresis loop for 20- and 40-h milled samples was 204 and 254 Oe, respectively. In spite of the mostly observed exchange coupling systems being ferromagnetic/antiferromagnetic systems, in this research the exchange coupling occurred between ferrimagnetic phases. The large difference between coercivity values at 300 and 4 k revealed that superparamagnetic particles constitute a large volume fraction of the milled nanocomposites.

  9. Calcium, Strontium and Barium Homogeneous Catalysts for Fine Chemicals Synthesis.

    PubMed

    Sarazin, Yann; Carpentier, Jean-François

    2016-12-01

    The large alkaline earths (Ae), calcium, strontium and barium, have in the past 15 years yielded a brand new generation of heteroleptic molecular catalysts for the production of fine chemicals. However, the integrity of these complexes is often plagued by ligand redistribution equilibria in solution. This personal account retraces the paths followed in our research group towards the design of stable heteroleptic alkalino-earth complexes, including the use of intramolecular noncovalent Ae···H-Si and Ae···F-C interactions. Their implementation as homogenous precatalysts for reactions such as the intramolecular and intermolecular hydroamination and hydrophosphination of activated alkenes, the hydrophosphonylation of ketones, and the dehydrogenative coupling of amines and hydrosilanes that enable the efficient and controlled formations of CP, CN, or SiN σ-bonds, is presented in a synthetic perspective that highlights their overall outstanding catalytic performance. © 2016 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Thin film barium strontium titanate ferroelectric varactors for microwave applications

    NASA Astrophysics Data System (ADS)

    Yue, Hailing; Spatz, Devin; Wang, Shu; Shin, Eunsung; Subramanyam, Guru

    2015-11-01

    Analog phase shifters are investigated with a periodic structure that includes Barium Strontium Titanate ferroelectric thin film varactors in shunt or serial connection to the coplanar waveguide transmission line. The phase shift is achieved by applying a DC bias to the varactors and changing the reactance in the circuit. The goal of this paper is to characterize the shunt capacitive varactors regarding the voltage dependence of the capacitance, loss tangent, and insertion losses at different bias voltages. Quality factor analysis is also conducted taking the parasitic effects into account. Repeated measurements show that the capacitance of a single cell is tuned from 0.8pF to 0.2pF under a DC bias of 0-10V while the loss tangent is kept under 0.01 in the frequency range of 0-40GHz. Insertion loss is tuned from -4dB to less than -0.6dB from 0 to 10V with a Figure of Merit of 14 degrees/dB at 10GHz and the total quality factor of the unit cell is around 6.7 to 10 at 10GHz with matched port impedance. By cascading 10-25 single unit cells, the phase shift is expected to reach 360 degrees with minimum insertion loss.

  11. Abundance analysis of s-process enhanced barium stars

    NASA Astrophysics Data System (ADS)

    Mahanta, Upakul; Karinkuzhi, Drisya; Goswami, Aruna; Duorah, Kalpana

    2016-12-01

    Detailed chemical composition studies of stars with enhanced abundances of neutron-capture elements can provide observational constraints for neutron-capture nucleosynthesis studies and clues for understanding their contribution to the Galactic chemical enrichment. We present abundance results from high-resolution spectral analyses of a sample of four chemically peculiar stars characterized by s-process enhancement. High-resolution spectra (R ˜ 42 000) of these objects spanning a wavelength range from 4000 to 6800 Å are taken from the ELODIE archive. We have estimated the stellar atmospheric parameters, the effective temperature Teff, the surface gravity log g and metallicity [Fe/H] from local thermodynamic equilibrium analysis using model atmospheres. We report estimates of elemental abundances for several neutron-capture elements, Sr, Y, Zr, Ba, La, Ce, Pr, Nd, Sm, Eu and Dy. While HD 49641 and HD 58368 show [Ba/Fe] ≥ 1.16, the other two objects HD 119650 and HD 191010 are found to be mild barium stars with [Ba/Fe] ˜ 0.4. The derived abundances of the elements are interpreted on the basis of existing theories for understanding their origin and evolution.

  12. High-pressure phase transition observed in barium hydride

    NASA Astrophysics Data System (ADS)

    Smith, Jesse S.; Desgreniers, Serge; Tse, John S.; Klug, Dennis D.

    2007-08-01

    The pressure-dependent structural and vibrational properties of barium hydride have been studied up to 22 GPa at room temperature by means of powder x-ray diffraction, Raman spectroscopy, and first-principles calculations. At ambient conditions, BaH2 crystallizes in the cotunnite structure (Pnma). A reversible, first-order structural phase transition is observed at 1.6 GPa. The high-pressure phase can be indexed by a hexagonal unit cell with a proposed Ni2In structure (P63/mmc), with the Ba and H atoms in special positions. The experimental volume compression of the high-pressure phase yields an isothermal bulk modulus B0=24(1) GPa (B0' fixed at 4.13). This compares favorably with the results of the first-principles calculations, which reproduce the first-order nature of the transition. The relevance of these results is discussed in the contexts of metal hydrides in particular and ionic AX2(A =metal) compounds in general.

  13. Facile growth of barium oxide nanorods: structural and optical properties.

    PubMed

    Ahmad, Naushad; Wahab, Rizwan; Alam, Manawwer

    2014-07-01

    This paper reports a large-scale synthesis of barium oxide nanorods (BaO-NRs) by simple solution method at a very low-temperature of - 60 degrees C. The as-grown BaO-NRs were characterized in terms of their morphological, structural, compositional, optical and thermal properties. The morphological characterizations of as-synthesized nanorods were done by scanning electron microscopy (SEM) which confirmed that the synthesized products are rod shaped and grown in high density. The nanorods exhibits smooth and clean surfaces throughout their lengths. The crystalline property of the material was analyzed with X-ray diffraction pattern (XRD). The compositional and thermal properties of synthesized nanorods were observed via Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis which confirmed that the synthesized nanorods are pure BaO and showed good thermal stability. The nanorods exhibited good optical properties as was confirmed from the room-temperature UV-vis spectroscopy. Finally, a plausible mechanism for the formation of BaO-NRs is also discussed in this paper.

  14. Small Polarons and Point Defects in Barium Cerate

    NASA Astrophysics Data System (ADS)

    Swift, Michael; Janotti, Anderson; van de Walle, Chris G.

    2015-03-01

    Barium cerate (BaCeO3) is a well-known proton-conducting material. In applications, it is frequently doped (for instance with yttrium) to increase stability and promote hydrogen uptake. However, the microscopic mechanisms of ionic conductivity and the effects of doping and native defects are still not fully understood. Many of the obstacles to the theoretical study of this material stem from the nature of the conduction band, which is made up of cerium 4 f states. These states present a challenge to first-principles techniques based on density functional theory within the standard approximations for exchange and correlation. Using a hybrid functional, we investigate the effects of hydrogen impurities and native defects on the electrical and optical properties of BaCeO3. We discuss the tendency of excess electrons or holes to localize in the form of small polarons. We also explore the interactions of polarons with hydrogen impurities and oxygen vacancies, and their impact on luminescence properties. This work was supported by the DOE and ARO.

  15. Hydrogen diffusion in lead zirconate titanate and barium titanate

    SciTech Connect

    Alvine, K. J.; Vijayakumar, M.; Bowden, M. E.; Schemer-Kohrn, A. L.; Pitman, S. G.

    2012-08-28

    Hydrogen is a potential clean-burning, next-generation fuel for vehicle and stationary power. Unfortunately, hydrogen is also well known to have serious materials compatibility issues in metals, polymers, and ceramics. Piezoelectric actuator materials proposed for low-cost, high efficiency high-pressure hydrogen internal combustion engines (HICE) are known to degrade rapidly in hydrogen. This limits their potential use and poses challenges for HICE. Hydrogen-induced degradation of piezoelectrics is also an issue for low-pressure hydrogen passivation in ferroelectric random access memory. Currently, there is a lack of data in the literature on hydrogen species diffusion in piezoelectrics in the temperature range appropriate for the HICE as charged via a gaseous route. We present 1HNMR quantification of the local hydrogen species diffusion within lead zirconate titanate and barium titanate on samples charged by exposure to high-pressure gaseous hydrogen ~32 MPa. We discuss results in the context of theoretically predicted interstitial hydrogen lattice sites and aqueous charging experiments from existing literature.

  16. Barium inhibits arsenic-mediated apoptotic cell death in human squamous cell carcinoma cells.

    PubMed

    Yajima, Ichiro; Uemura, Noriyuki; Nizam, Saika; Khalequzzaman, Md; Thang, Nguyen D; Kumasaka, Mayuko Y; Akhand, Anwarul A; Shekhar, Hossain U; Nakajima, Tamie; Kato, Masashi

    2012-06-01

    Our fieldwork showed more than 1 μM (145.1 μg/L) barium in about 3 μM (210.7 μg/L) arsenic-polluted drinking well water (n = 72) in cancer-prone areas in Bangladesh, while the mean concentrations of nine other elements in the water were less than 3 μg/L. The types of cancer include squamous cell carcinomas (SCC). We hypothesized that barium modulates arsenic-mediated biological effects, and we examined the effect of barium (1 μM) on arsenic (3 μM)-mediated apoptotic cell death of human HSC-5 and A431 SCC cells in vitro. Arsenic promoted SCC apoptosis with increased reactive oxygen species (ROS) production and JNK1/2 and caspase-3 activation (apoptotic pathway). In contrast, arsenic also inhibited SCC apoptosis with increased NF-κB activity and X-linked inhibitor of apoptosis protein (XIAP) expression level and decreased JNK activity (antiapoptotic pathway). These results suggest that arsenic bidirectionally promotes apoptotic and antiapoptotic pathways in SCC cells. Interestingly, barium in the presence of arsenic increased NF-κB activity and XIAP expression and decreased JNK activity without affecting ROS production, resulting in the inhibition of the arsenic-mediated apoptotic pathway. Since the anticancer effect of arsenic is mainly dependent on cancer apoptosis, barium-mediated inhibition of arsenic-induced apoptosis may promote progression of SCC in patients in Bangladesh who keep drinking barium and arsenic-polluted water after the development of cancer. Thus, we newly showed that barium in the presence of arsenic might inhibit arsenic-mediated cancer apoptosis with the modulation of the balance between arsenic-mediated promotive and suppressive apoptotic pathways.

  17. High pressure–low temperature phase diagram of barium: Simplicity versus complexity

    SciTech Connect

    Desgreniers, Serge; Tse, John S.; Matsuoka, Takahiro; Ohishi, Yasuo

    2015-11-30

    Barium holds a distinctive position among all elements studied upon densification. Indeed, it was the first example shown to violate the long-standing notion that high compression of simple metals should preserve or yield close-packed structures. From modest pressure conditions at room temperature, barium transforms at higher pressures from its simple structures to the extraordinarily complex atomic arrangements of the incommensurate and self-hosting Ba-IV phases. By a detailed mapping of the pressure/temperature structures of barium, we demonstrate the existence of another crystalline arrangement of barium, Ba-VI, at low temperature and high pressure. The simple structure of Ba-VI is unlike that of complex Ba-IV, the phase encountered in a similar pressure range at room temperature. First-principles calculations predict Ba-VI to be stable at high pressure and superconductive. The results illustrate the complexity of the low temperature-high pressure phase diagram of barium and the significant effect of temperature on structural phase transformations.

  18. Chromospherically active stars. 6: Giants with compact hot companions and the barium star scenario

    NASA Technical Reports Server (NTRS)

    Fekel, Francis C.; Henry, Gregory W.; Busby, Michael R.; Eitter, Joseph J.

    1993-01-01

    We have determined spectroscopic orbits for three chromospherically active giants that have hot compact companions. They are HD 160538 (K0 III + wd, P = 904 days), HD 165141 (G8 III + wd, P approximately 5200 days), and HD 185510 (K0 III + sdB, P = 20.6619 days). By fitting an IUE spectrum with theoretical models, we find the white dwarf companion of HD 165141 has a temperature of about 35000 K. Spectral types and rotational velocities have been determined for the three giants and distances have been estimated. These three systems and 39 Ceti are compared with the barium star mass-transfer scenario. The long-period mild barium giant HD 165141 as well as HD 185510 and 39 Ceti, which have relatively short periods and normal abundance giants, appear to be consistent with this scenario. The last binary, HD 160538, a system with apparently near solar abundances, a white dwarf companion, and orbital characteristics similar to many barium stars, demonstrates that the existence of a white-dwarf companion is insufficient to produce a barium star. The paucity of systems with confirmed white-dwarf companions makes abundance analyses of HD 160538 and HD 165141 of great value in examining the role of metallicity in barium star formation.

  19. Barium Tagging in Solid Xenon for the nEXO Experiment

    NASA Astrophysics Data System (ADS)

    Chambers, Christopher; Craycraft, Adam; Walton, Timothy; Fairbank, William; nEXO Collaboration

    2016-09-01

    The proposed nEXO experiment utilizes a tonne-scale liquid xenon time projection chamber to search for neutrinoless double beta decay in xenon-136. Positive observation of this decay would determine the nature of the neutrino to be a MAJORANA particle, as well as measure the absolute neutrino mass scale. A critical concern for any rare decay search is reducing or eliminating backgrounds that cannot be distinguished from signal. A powerful background discrimination technique is positive identification of the daughter atom of the decay, in this case barium. This technique, called ``barium tagging'' may be available for a second phase of nEXO operation, allowing for neutrino mass sensitivity beyond the inverted mass hierarchy. Development is underway on a scheme to capture the barium daughter in solid xenon with a cryogenic probe and detect the barium by laser-induced fluorescence inside the solid xenon sample. This presentation reports results on imaging of single barium atoms frozen in a solid xenon matrix, as well as the progress on the freezing and removal of a solid xenon sample from liquid xenon. Graduated.

  20. Chromospherically active stars. 11: Giant with compact hot companions and the barium star scenario

    NASA Technical Reports Server (NTRS)

    Fekel, Francis C.; Henry, Gregory W.; Busby, Michael R.; Eitter, Joseph J.

    1993-01-01

    We have determined spectroscopic orbits for three chromsopherically active giants that have hot compact companions. They are HD 160538 (KO III + wd, P = 904 days), HD 165141 (G8 III + wd, P approximately 5200 days), and HD 185510 (KO III + sdB, P = 20.6619 days). By fitting an IUE spectrum with theoretical models, we find the white dwarf companion of HD 165141 has a temperature of about 35,000 K. Spectral types and rotational velocities have been determined for the three giants and distances have been estimated. These three systems and 39 Ceti are compared with the barium star mass-transfer scenario. The long-period mild barium giant HD 165141 as well as HD 185510 and 39 Ceti, which have relatively short periods and normal abundance giants, appear to be consistent with this scenario. The last binary, HD 160538, a system with apparently near solar abundances, a white dwarf companion, and orbital characteristics similar to many barium stars, demonstrates that the existence of a white dwarf companion is insufficient to produce a barium star. The paucity of systems with confirmed white dwarf companions makes abundance analyses of HD 160538 and HD 165141 of great value in examining the role of metallicity in barium star formation.

  1. [Comparative analysis chest CT 3D reconstruction and esophagus barium swallow in esophagus foreign body].

    PubMed

    Xu, Kai; Chu, Hanqi; Huang, Xiaowen; Cui, Yonghua

    2010-06-01

    To compare the diagnosis and therapeutic between chest computed tomography three-dimensional reconstruction and esophagus barium swallow in esophagus foreign body. retrospective analyze one hundred and thirty six patients who suffered from esophagus foreign body in our hospital, 97 cases using esophagus barium swallow, 17 cases using chest computed tomography three-dimensional reconstruction, 15 cases using both. The patients who showed positive of esophagus foreign body in esophagus barium swallow or chest computed tomography three-dimensional reconstruction, 91.8% (89/97) cases or 88.2% (15/17) cases found esophagus foreign bodies finally. All cases successfully took out the esophagus foreign bodies only through one operation which used chest computed tomography three-dimensional reconstruction as primary examination, while only 91.0% for those used esophagus barium swallow as primary examination. Both chest computed tomography three-dimensional reconstruction and esophagus barium swallow showed high diagnostic efficiency on esophagus foreign body. Chest computed tomography three-dimensional reconstruction had advantages in patients with one of following conditions: (1) esophagus foreign body located in the middle of the esophagus, especially complicated with esophagus perforation; (2) with fever, high white blood count, presence of abscess surrounding the esophagus was suspected; (3) with dyspnea; (4) with a history of esophagus foreign body longer than 5 days; (5) younger than 6 years old.

  2. Cadmium, zinc, copper, and barium in foraminifera tests

    NASA Astrophysics Data System (ADS)

    Boyle, Edward A.

    1981-03-01

    The concentrations of cadmium, zinc, copper and barium have been determined on 2-mg samples of single-species foraminifera populations. Cleaning techniques were tested using North Atlantic core tops, and followed by a detailed downcore study for the last 30,000 years in South Atlantic core V22-174. Raw foram tests cleaned by crushing followed by ultrasonic removal of fine-grained material, and dissolved in a pH 5.5 acetate buffer, contain appreciable amounts of trace elements associated with ferromanganese and alumino-silicate contaminants. A reductive/complexing cleaning treatment reduces ferromanganese contamination by 1-2 orders of magnitude. Acetate buffers at pH 5.5 complex iron and raise the solubility of ferromanganese oxides; these buffers are unsuitable for separating carbonate lattice-bound trace elements from the fraction associated with ferromanganese phases. Improved mechanical and ultrasonic reductive cleaning combined with a mild dissolution in distilled water under 1 atm. P CO 2 reduces contaminant levels another order of magnitude. The Cd and Zn concentrations (order 10 -8 mole Cd/mole Ca and 10 -5 mole Zn/mole Ca) of species with low surface area show an increase with decreasing isotopic temperatures. This increase is consistent with the increasing concentrations of these metals from low values in surface waters to higher values at depth. The variance of Cd and Zn over the last 30,000 years in the central South Atlantic is consistent with the probable variability of the dissolved trace elements at the calcification levels of the species analyzed. Cu and Ba are irreproducible and probably sensitive to residual contaminant phases. The trace element content of the tests differs from levels observed in a recent coprecipitation study. Foraminifera may be a significant vector in zinc cycling in the ocean.

  3. Relaxor properties of barium titanate crystals grown by Remeika method

    NASA Astrophysics Data System (ADS)

    Roth, Michel; Tiagunov, Jenia; Dul'kin, Evgeniy; Mojaev, Evgeny

    2017-06-01

    Barium titanate (BaTiO3, BT) crystals have been grown by the Remeika method using both the regular KF and mixed KF-NaF (0.6-0.4) solvents. Typical acute angle ;butterfly wing; BT crystals have been obtained, and they were characterized using x-ray diffraction, scanning electron microscopy (including energy dispersive spectroscopy), conventional dielectric and acoustic emission methods. A typical wing has a triangular plate shape which is up to 0.5 mm thick with a 10-15 mm2 area. The plate has a (001) habit and an atomically smooth outer surface. Both K+ and F- solvent ions are incorporated as dopants into the crystal lattice during growth substituting for Ba2+ and O2- ions respectively. The dopants' distribution is found to be inhomogeneous, their content being almost an order of magnitude higher (up to 2 mol%) at out surface of the plate relatively to the bulk. A few μm thick surface layer is formed where a multidomain ferroelectric net is confined between two≤1 μm thick dopant-rich surfaces. The layer as a whole possess relaxor ferroelectric properties, which is apparent from the appearance of additional broad maxima, Tm, in the temperature dependence of the dielectric permittivity around the ferroelectric phase transition. Intense acoustic emission responses detected at temperatures corresponding to the Tm values allow to observe the Tm shift to lower temperatures at higher frequencies, or dispersion, typical for relaxor ferroelectrics. The outer surface of the BT wing can thus serve as a relaxor thin film for various electronic application, such as capacitors, or as a substrate for BT-based multiferroic structure. Crystals grown from KF-NaF fluxes contain sodium atoms as an additional impurity, but the crystal yield is much smaller, and while the ferroelectric transition peak is diffuse it does not show any sign of dispersion typical for relaxor behavior.

  4. TWO BARIUM STARS IN THE OPEN CLUSTER NGC 5822

    SciTech Connect

    Katime Santrich, O. J.; Pereira, C. B.; De Castro, D. B. E-mail: claudio@on.br

    2013-08-01

    Open clusters are very useful examples to explain the constraint of the nucleosynthesis process with the luminosities of stars because the distances of the clusters are better known than those of field stars. We carried out a detailed spectroscopic analysis to derive the chemical composition of two red giants in the young open cluster NGC 5822, NGC 5822-2, and NGC 5822-201. We obtained abundances of C, N, O, Na, Mg, Al, Ca, Si, Ti, Ni, Cr, Y, Zr, La, Ce, and Nd. The atmospheric parameters of the studied stars and their chemical abundances were determined using high-resolution optical spectroscopy. We employed the local thermodynamic equilibrium model atmospheres of Kurucz and the spectral analysis code MOOG. The abundances of the light elements were derived using the spectral synthesis technique. We found that NGC 5822-2 and -201 have, respectively, a mean overabundance of the elements created by the s-process, ''s'', with the notation [s/Fe] of 0.77 {+-} 0.12 and 0.83 {+-} 0.05. These values are higher than those for field giants of similar metallicity. We also found that NGC 5822-2 and -201 have, respectively, luminosities of 140 L{sub Sun} and 76 L{sub Sun }, which are much lower than the luminosity of an asymptotic giant branch star. We conclude that NGC 5822-2 and NGC 5822-201 are two new barium stars first identified in the open cluster NGC 5822. The mass transfer hypothesis is the best scenario to explain the observed overabundances.

  5. Strontium barium niobate single crystals, growth and ferroelectric properties

    NASA Astrophysics Data System (ADS)

    Lukasiewicz, T.; Swirkowicz, M. A.; Dec, J.; Hofman, W.; Szyrski, W.

    2008-04-01

    Single crystals of strontium-barium niobate Sr xBa 1-xNb 2O 6 (SBN) undoped and doped with Ce or Cr were grown by the Czochralski method. The inductive heating system was used. In order to improve conditions of growth, a crucible-base cooling was introduced. Single crystals of the following nominal compositions have been obtained: Sr 0.4Ba 0.6Nb 2O 6, Sr 0.5Ba 0.5Nb 2O 6, Sr 0.61Ba 0.39Nb 2O 6 (congruent melting) and Sr 0.75Ba 0.25Nb 2O 6, designated hereafter as SBN40, SBN50, SBN61 and SBN75. They were up to 22 mm in diameter and 40 mm in length with characteristic 24 faces, free from striations and other extended defects. All the crystals were grown in the [0 0 1] direction. The dopants (Ce or Cr) were added to the SBN61 composition. By use of ICP-OES method, the chemical compositions were checked. Etch pit density was also measured. In the case of the undoped single crystals, it was found to be 2.4×10 2-5.6×10 3 cm -2 but in the case of Ce or Cr doping, it increased up to 3.6×10 4-1.8×10 5 cm -2. Investigations of the linear dielectric response measured within 10 0⩽ f⩽10 5 Hz along the polar c-axis of four obtained single-crystalline SBN compounds revealed a gradual crossover from conventional ferroelectric (SBN40) to extreme relaxor (SBN75) behavior.

  6. Electrical properties of niobium doped barium bismuth-titanate ceramics

    SciTech Connect

    Bobić, J.D.; Vijatović Petrović, M.M.; Banys, J.; Stojanović, B.D.

    2012-08-15

    Highlights: ► Pure and doped BaBi{sub 4}Ti{sub 4}O{sub 15} were prepared via the solid-state reaction method. ► The grain size was suppressed in Nb-doped samples. ► The diffuseness of the dielectric peak increased with dopant concentration. ► Niobium affected on relaxor behavior of barium bismuth titanate ceramics. ► The conductivity change was noticed in doped samples. -- Abstract: BaBi{sub 4}Ti{sub 4–5/4x}Nb{sub x}O{sub 15} (BBNTx, x = 0, 0.05, 0.15, 0.30) ceramics have been prepared by solid state method. XRD data indicate the formation of single-phase-layered perovskites for all compositions. SEM micrographs suggest that the grain size decreases with Nb doping. The effect of niobium doping on the dielectric and relaxor behavior of BaBi{sub 4}Ti{sub 4}O{sub 15} ceramics was investigated in a wide range of temperatures (20–777 °C) and frequencies (1.21 kHz to 1 MHz). Nb doping influences T{sub c} decrease as well as the decrease of dielectric permittivity at Curie temperature. At room temperature, undoped BaBi{sub 4}Ti{sub 4}O{sub 15} exhibits dielectric constant of ∼204 at 100 kHz, that slightly increases with Nb doping. The conductivity of BBNT5 ceramics is found to be lower than that of other investigated compositions. The value of activation energy of σ{sub DC} was found to be 0.89 eV, 1.01 eV, 0.93 eV and 0.71 eV for BBT, BBNT5, BBNT15 and BBNT30, respectively.

  7. Evaluation of antibacterial properties of Barium Zirconate Titanate (BZT) nanoparticle.

    PubMed

    Mohseni, Simin; Aghayan, Mahdi; Ghorani-Azam, Adel; Behdani, Mohammad; Asoodeh, Ahmad

    2014-01-01

    So far, the antibacterial activity of some organic and inorganic compounds has been studied. Barium zirconate titanate [Ba(ZrxTi₁-x)O₃] (x = 0.05) nanoparticle is an example of inorganic materials. In vitro studies have provided evidence for the antibacterial activity of this nanoparticle. In the current study, the nano-powder was synthesized by sol-gel method. X-ray diffraction showed that the powder was single-phase and had a perovskite structure at the calcination temperature of 1000 °C. Antibacterial activity of the desired nanoparticle was assessed on two gram-positive (Staphylococcus aureus PTCC1431 and Micrococcus luteus PTCC1625) and two gram-negative (Escherichia coli HP101BA 7601c and clinically isolated Klebsiella pneumoniae) bacteria according to Radial Diffusion Assay (RDA). The results showed that the antibacterial activity of BZT nano-powder on both gram-positive and gram-negative bacteria was acceptable. The minimum inhibitory concentration of this nano-powder was determined. The results showed that MIC values for E. coli, K. pneumoniae, M. luteus and S. aureus were about 2.3 μg/mL, 7.3 μg/mL, 3 μg/mL and 12 μg/mL, respectively. Minimum bactericidal concentration (MBC) was also evaluated and showed that the growth of E. coli, K. pneumoniae, M. luteus and S. aureus could be decreased at 2.3, 14, 3 and 18 μg/mL of BZT. Average log reduction in viable bacteria count in time-kill assay ranged between 6 Log₁₀ cfu/mL to zero after 24 h of incubation with BZT nanoparticle.

  8. Evaluation of antibacterial properties of Barium Zirconate Titanate (BZT) nanoparticle

    PubMed Central

    Mohseni, Simin; Aghayan, Mahdi; Ghorani-Azam, Adel; Behdani, Mohammad; Asoodeh, Ahmad

    2014-01-01

    So far, the antibacterial activity of some organic and inorganic compounds has been studied. Barium zirconate titanate [Ba(ZrxTi1-x)O3] (x = 0.05) nanoparticle is an example of inorganic materials. In vitro studies have provided evidence for the antibacterial activity of this nanoparticle. In the current study, the nano-powder was synthesized by sol-gel method. X-ray diffraction showed that the powder was single-phase and had a perovskite structure at the calcination temperature of 1000 °C. Antibacterial activity of the desired nanoparticle was assessed on two gram-positive (Staphylococcus aureus PTCC1431 and Micrococcus luteus PTCC1625) and two gram-negative (Escherichia coli HP101BA 7601c and clinically isolated Klebsiella pneumoniae) bacteria according to Radial Diffusion Assay (RDA). The results showed that the antibacterial activity of BZT nano-powder on both gram-positive and gram-negative bacteria was acceptable. The minimum inhibitory concentration of this nano-powder was determined. The results showed that MIC values for E. coli, K. pneumoniae, M. luteus and S. aureus were about 2.3 μg/mL, 7.3 μg/mL, 3 μg/mL and 12 μg/mL, respectively. Minimum bactericidal concentration (MBC) was also evaluated and showed that the growth of E. coli, K. pneumoniae, M. luteus and S. aureus could be decreased at 2.3, 14, 3 and 18 μg/mL of BZT. Average log reduction in viable bacteria count in time-kill assay ranged between 6 Log10 cfu/mL to zero after 24 h of incubation with BZT nanoparticle. PMID:25763046

  9. Dominant toughening mechanisms in barium aluminosilicate (BAS) glass-ceramics

    NASA Astrophysics Data System (ADS)

    Griggs, Jason Alan

    The purpose of this study was to develop a barium aluminosilicate (BAS) glass-ceramic with improved strength and fracture toughness by controlling the morphology of the constituent phases through a series of thermal crystallization treatments. The specific objectives of this study were to (1) determine which toughening mechanisms are active in the BAS system, (2) provide quantitative estimates of the relative contributions of those mechanisms, and (3) identify the processing conditions that correspond to a glass-ceramic with optimal fracture toughness. The BAS system was chosen for this study because of its potential applications in CAD-CAM production of dental prostheses. It is concluded that load sharing and crack deflection are the only major sources of toughening in the BAS system. Theoretical predictions for toughening increases due to load sharing and crack deflection are insufficient to account for 100% of the increases observed. The excess increase in fracture toughness is produced by thermal mismatch between and crystal and glass phases. The strength and fracture toughness of BAS glass-ceramics are shown to increase with increasing crystal growth time over the entire range of treatments studied. The strength and fracture toughness increased from 63 ± 8 MPa and 0.89 ± 0.05 MPa*msp{1/2}, respectively for BAS glass to 141 ± 8 MPa and 1.87 ± 0.07 MPa*msp{1/2} respectively for a glass-ceramic treated for 256 h at 975sp°C. Fracture toughness was also shown to increase with increasing mean crystal size. A non-stoichiometric glass composition results in thermal compatibility between the glass and crystal phases, eliminating the weakening at large crystal sizes that can be associated with a spontaneous microcracking mechanism.

  10. Sputtered Modified Barium Titanate for Thin-Film Capacitor Applications

    PubMed Central

    Reynolds, Glyn J.; Kratzer, Martin; Dubs, Martin; Felzer, Heinz; Mamazza, Robert

    2012-01-01

    New apparatus and a new process for the sputter deposition of modified barium titanate thin-films were developed. Films were deposited at temperatures up to 900 °C from a Ba0.96Ca0.04Ti0.82Zr0.18O3 (BCZTO) target directly onto Si, Ni and Pt surfaces and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Film texture and crystallinity were found to depend on both deposition temperature and substrate: above 600 °C, the as-deposited films consisted of well-facetted crystallites with the cubic perovskite structure. A strongly textured Pt (111) underlayer enhanced the (001) orientation of BCZTO films deposited at 900 °C, 10 mtorr pressure and 10% oxygen in argon. Similar films deposited onto a Pt (111) textured film at 700 °C and directly onto (100) Si wafers showed relatively larger (011) and diminished intensity (00ℓ) diffraction peaks. Sputter ambients containing oxygen caused the Ni underlayers to oxidize even at 700 °C: Raising the process temperature produced more diffraction peaks of NiO with increased intensities. Thin-film capacitors were fabricated using ~500 nm thick BCZTO dielectrics and both Pt and Ni top and bottom electrodes. Small signal capacitance measurements were carried out to determine capacitance and parallel resistance at low frequencies and from these data, the relative permittivity (εr) and resistivity (ρ) of the dielectric films were calculated; values ranged from ~50 to >2,000, and from ~104 to ~1010 Ω∙cm, respectively. PMID:28816997

  11. FIRST DIRECT EVIDENCE THAT BARIUM DWARFS HAVE WHITE DWARF COMPANIONS

    SciTech Connect

    Gray, R. O.; McGahee, C. E.; Griffin, R. E. M.; Corbally, C. J. E-mail: cmcgahe@g.clemson.edu E-mail: corbally@as.arizona.edu

    2011-05-15

    Barium II (Ba) stars are chemically peculiar F-, G-, and K-type objects that show enhanced abundances of s-process elements. Since s-process nucleosynthesis is unlikely to take place in stars prior to the advanced asymptotic giant branch (AGB) stage, the prevailing hypothesis is that each present Ba star was contaminated by an AGB companion which is now a white dwarf (WD). Unless the initial mass ratio of such a binary was fairly close to unity, the receiving star is thus at least as likely to be a dwarf as a giant. So although most known Ba stars appear to be giants, the hypothesis requires that Ba dwarfs be comparably plentiful and moreover that they should all have WD companions. However, despite dedicated searches with the IUE satellite, no WD companions have been directly detected to date among the classical Ba dwarfs, even though some 90% of those stars are spectroscopic binaries, so the contamination hypothesis is therefore presently in some jeopardy. In this paper, we analyze recent deep, near-UV and far-UV Galaxy Evolution Explorer (GALEX) exposures of four of the brightest of the class (HD 2454, 15360, 26367, and 221531), together with archived GALEX data for two newly recognized Ba dwarfs: HD 34654 and HD 114520 (which also prove to be spectroscopic binaries). The GALEX observations of the Ba dwarfs as a group show a significant far-UV excess compared to a control sample of normal F-type dwarfs. We suggest that this ensemble far-UV excess constitutes the first direct evidence that Ba dwarfs have WD companions.

  12. Kinetic analysis of barium currents in chick cochlear hair cells.

    PubMed Central

    Zidanic, M; Fuchs, P A

    1995-01-01

    Inward barium current (IBa) through voltage-gated calcium channels was recorded from chick cochlear hair cells using the whole-cell clamp technique. IBa was sensitive to dihydropyridines and insensitive to the peptide toxins omega-agatoxin IVa, omega-conotoxin GVIa, and omega-conotoxin MVIIC. Changing the holding potential over a -40 to -80 mV range had no effect on the time course or magnitude of IBa nor did it reveal any inactivating inward currents. The activation of IBa was modeled with Hodgkin-Huxley m2 kinetics. The time constant of activation, tau m, was 550 microseconds at -30 mV and gradually decreased to 100 microseconds at +50 mV. A Boltzmann fit to the activation curve, m infinity, yielded a half activation voltage of -15 mV and a steepness factor of 7.8 mV. Opening and closing rate constants, alpha m and beta m, were calculated from tau m and m infinity, then fit with modified exponential functions. The H-H model derived by evaluating the exponential functions for alpha m and beta m not only provided an excellent fit to the time course of IBa activation, but was predictive of the time course and magnitude of the IBa tail current. No differences in kinetics or voltage dependence of activation of IBa were found between tall and short hair cells. We conclude that both tall and short hair cells of the chick cochlea predominantly, if not exclusively, express noninactivating L-type calcium channels. These channels are therefore responsible for processes requiring voltage-dependent calcium entry through the basolateral cell membrane, such as transmitter release and activation of Ca(2+)-dependent K+ channels. PMID:7787021

  13. Cathode temperature reduction by addition of Barium in high power Lithium plasma thrusters

    NASA Astrophysics Data System (ADS)

    Polk, James; Tikhonov, Viktor; Semenikhin, Sergei; Kim, Vladimir

    2000-01-01

    Lithium Lorentz Force Accelerators (LFA's) are capable of processing very high power levels and are therefore applicable to a wide range of challenging missions. The cathode in these coaxial discharge devices operates at a very high temperature to supply the required current and appears to be the primary life-limiting component. One potential method for lowering the cathode temperature is to add a small amount of barium to the lithium propellant. An analytical model of the surface kinetics of this system shows that a relatively small partial pressure of barium can dramatically reduce the cathode operating temperature. Preliminary experiments with a lithium-fuelled thruster demonstrated temperature reductions of 350-400 K with barium addition. .

  14. The review of various synthesis methods of barium titanate with the enhanced dielectric properties

    SciTech Connect

    More, S. P.; Topare, R. J.

    2016-05-06

    The Barium Titanate is a very well known dielectric ceramic belongs to perovskite structure. It has very wide applications in the field of electronic, electro ceramic, electromechanical and electro-optical applications. Barium Titanate has very high dielectric constant as well as low dielectric loss. Substituted dielectrics are one of the most important technological compounds in modern electro ceramics. Its electrical properties can be tuned flexibly by a simple substitution technique. This has encouraged researchers to select a typical cation to be substituted at cationic sites. In the present paper, the review of various synthesis methods of Barium Titanate compound with the effect of different dopants, the grain size on the dielectric properties at various temperatures is discussed.

  15. Observation and theory of the barium releases from the CRRES satellite

    NASA Technical Reports Server (NTRS)

    Bernhardt, P. A.; Huba, J. D.; Scales, W. A.; Wescott, E. M.; Stenbaek-Nielsen, H. C.

    1992-01-01

    The relationship between releases of barium from the NASA Combined Release and Radiation Effects Satellite (CRRES) and enhanced auroral activity is discussed with reference to observational data. Barium releases were conducted at a variety of altitudes and injection velocities, and plasma irregularities are reported as a result of the interactions. Auroral activity increased within 5 min of each release, and references are made to the effects on diamagnetic cavities, bulk ion motion, and stimulated electron and ion precipitation. Artificially created structured diamagnetic cavities are noted for each release, plasma waves are generated by the high-speed ion clouds, and enhanced ionization is found in the critical ionization-velocity process. Barium releases are effective in stimulating electron precipitation, and the observed irregularities are related to cycloid bunching of the initial ion distributions.

  16. SAD phasing with in-house cu Ka radiation using barium as anomalous scatterer.

    PubMed

    Dhanasekaran, V; Velmurugan, D

    2011-12-01

    Phasing of lysozyme crystals using co-crystallized barium ions was performed using single-wavelength anomalous diffraction (SAD) method using Cu Ka radiation with in-house source of data collection. As the ion binding sites vary with respect to the pH of the buffer during crystallization, the highly isomorphic forms of lysozyme crystals grown at acidic and alkaline pH were used for the study. Intrinsic sulphur anomalous signal was also utilized with anomalous signal from lower occupancy ions for phasing. The study showed that to solve the structure by SAD technique, 2.8-fold data redundancy was sufficient when barium was used as an anomalous marker in the in-house copper X-ray radiation source for data collection. Therefore, co-crystallization of proteins with barium containing salt can be a powerful tool for structure determination using lab source.

  17. Highly aligned arrays of high aspect ratio barium titanate nanowires via hydrothermal synthesis

    SciTech Connect

    Bowland, Christopher C.; Zhou, Zhi; Malakooti, Mohammad H.; Sodano, Henry A.

    2015-06-01

    We report on the development of a hydrothermal synthesis procedure that results in the growth of highly aligned arrays of high aspect ratio barium titanate nanowires. Using a multiple step, scalable hydrothermal reaction, a textured titanium dioxide film is deposited on titanium foil upon which highly aligned nanowires are grown via homoepitaxy and converted to barium titanate. Scanning electron microscope images clearly illustrate the effect the textured film has on the degree of orientation of the nanowires. The alignment of nanowires is quantified by calculating the Herman's Orientation Factor, which reveals a 58% improvement in orientation as compared to growth in the absence of the textured film. The ferroelectric properties of barium titanate combined with the development of this scalable growth procedure provide a powerful route towards increasing the efficiency and performance of nanowire-based devices in future real-world applications such as sensing and power harvesting.

  18. Plasma irregularities caused by cycloid bunching of the CRRES G-2 barium release

    NASA Technical Reports Server (NTRS)

    Bernhardt, P. A.; Huba, J. D.; Pongratz, M. B.; Simons, D. J.; Wolcott, J. H.

    1993-01-01

    The Combined Release and Radiation Effects Satellite (CRRES) spacecraft carried a number of barium thermite canisters for release into the upper atmosphere. The barium release labeled G-2 showed evidence of curved irregularities not aligned with the ambient magnetic field B. The newly discovered curved structures can be explained by a process called cycloid bunching. Cycloid bunching occurs when plasma is created by photoionization of a neutral cloud injected at high velocity perpendicular to B. If the injection velocity is much larger than the expansion speed of the cloud, the ion trail will form a cycloid that has irregularities spaced by the product of the perpendicular injection speed and the ion gyroperiod, Images of the solar-illuminated barium ions are compared with the results of a three-dimensional kinetic simulation. Cycloid bunching is shown to be responsible for the rapid generation of both curved and field-aligned irregularities in the CRRES G-2 experiment.

  19. Barium isotopes in individual presolar silicon carbide grains from the Murchison meteorite.

    SciTech Connect

    Savina, M. R.; Davis, A. M.; Tripa, C. E.; Pellin, M. J.; Clayton, R. N.; Lewis, R. S.; Amari, S.; Gallino, R.; Lugaro, M.; Univ. of Chicago; Washington Univ.; Univ. di Torino; Cambridge Univ.

    2003-09-01

    Barium isotopic compositions of single 2.3-5.3 {mu}m presolar SiC grains from the Murchison meteorite were measured by resonant ionization mass spectrometry. Mainstream SiC grains are enriched in s-process barium and show a spread in isotopic composition from solar to dominantly s-process. In the relatively coarse grain size fraction analyzed, there are large grain-to-grain variations of barium isotopic composition. Comparison of single grain data with models of nucleosynthesis in asymptotic giant branch (AGB) stars indicates that the grains most likely come from low mass carbon-rich AGB stars (1.5 to 3 solar masses) of about solar metallicity and with approximately solar initial proportions of r- and s-process isotopes. Measurements of single grains imply a wide variety of neutron-to-seed ratios, in agreement with previous measurements of strontium, zirconium and molybdenum isotopic compositions of single presolar SiC grains.

  20. Prompt ionization in the CRIT II barium releases. [Critical Ionization Tests

    NASA Technical Reports Server (NTRS)

    Torbert, R. B.; Kletzing, C. A.; Liou, K.; Rau, D.

    1992-01-01

    Observations of electron and ion distributions inside a fast neutral barium jet in the ionosphere show significant fluxes within 4 km of release, presumably related to beam plasma instability processes involved in the Critical Ionization Velocity (CIV) effect. Electron fluxes exceeding 5 x 10 exp 12/sq cm-str-sec-keV were responsible for ionizing both the streaming barium and ambient oxygen. Resulting ion fluxes seem to be consistent with 1-2 percent ionization of the fast barium, as reported by optical observations, although the extended spatial distribution of the optically observed ions is difficult to reconcile with the in situ observations. When the perpendicular velocity of the neutrals falls below critical values, these processes shut off. Although these observations resemble the earlier Porcupine experimental results (Haerendel, 1982), theoretical understanding of the differences between these data and that of earlier negative experiments is still lacking.

  1. Phase transition studies in barium and strontium titanates at microwave frequencies

    NASA Technical Reports Server (NTRS)

    Dahiya, Jai N.

    1993-01-01

    The objectives were the following: to understand the phase transformations in barium and strontium titanates as the crystals go from one temperature to the other; and to study the dielectric behavior of barium and strontium titanate crystals at a microwave frequency of 9.12 GHz and as a function of temperature. Phase transition studies in barium and strontium titanate are conducted using a cylindrical microwave resonant cavity as a probe. The cavity technique is quite successful in establishing the phase changes in these crystals. It appears that dipole relaxation plays an important role in the behavior of the dielectric response of the medium loading the cavity as phase change takes place within the sample. The method of a loaded resonant microwave cavity as applied in this work has proven to be sensitive enough to monitor small phase changes of the cavity medium.

  2. Observation and theory of the barium releases from the CRRES satellite

    SciTech Connect

    Bernhardt, P.A.; Huba, J.D.; Scales, W.A.; Wescott, E.M.; Stenbaek-Nielsen, H.C. Alaska, University, Fairbanks )

    1992-01-01

    The relationship between releases of barium from the NASA Combined Release and Radiation Effects Satellite (CRRES) and enhanced auroral activity is discussed with reference to observational data. Barium releases were conducted at a variety of altitudes and injection velocities, and plasma irregularities are reported as a result of the interactions. Auroral activity increased within 5 min of each release, and references are made to the effects on diamagnetic cavities, bulk ion motion, and stimulated electron and ion precipitation. Artificially created structured diamagnetic cavities are noted for each release, plasma waves are generated by the high-speed ion clouds, and enhanced ionization is found in the critical ionization-velocity process. Barium releases are effective in stimulating electron precipitation, and the observed irregularities are related to cycloid bunching of the initial ion distributions. 38 refs.

  3. Spectroscopy of Ba and Ba+ deposits in solid xenon for barium tagging in nEXO

    NASA Astrophysics Data System (ADS)

    Mong, B.; Cook, S.; Walton, T.; Chambers, C.; Craycraft, A.; Benitez-Medina, C.; Hall, K.; Fairbank, W.; Albert, J. B.; Auty, D. J.; Barbeau, P. S.; Basque, V.; Beck, D.; Breidenbach, M.; Brunner, T.; Cao, G. F.; Cleveland, B.; Coon, M.; Daniels, T.; Daugherty, S. J.; DeVoe, R.; Didberidze, T.; Dilling, J.; Dolinski, M. J.; Dunford, M.; Fabris, L.; Farine, J.; Feldmeier, W.; Fierlinger, P.; Fudenberg, D.; Giroux, G.; Gornea, R.; Graham, K.; Gratta, G.; Heffner, M.; Hughes, M.; Jiang, X. S.; Johnson, T. N.; Johnston, S.; Karelin, A.; Kaufman, L. J.; Killick, R.; Koffas, T.; Kravitz, S.; Krücken, R.; Kuchenkov, A.; Kumar, K. S.; Leonard, D. S.; Licciardi, C.; Lin, Y. H.; Ling, J.; MacLellan, R.; Marino, M. G.; Moore, D.; Odian, A.; Ostrovskiy, I.; Piepke, A.; Pocar, A.; Retiere, F.; Rowson, P. C.; Rozo, M. P.; Schubert, A.; Sinclair, D.; Smith, E.; Stekhanov, V.; Tarka, M.; Tolba, T.; Twelker, K.; Vuilleumier, J.-L.; Walton, J.; Weber, M.; Wen, L. J.; Wichoski, U.; Yang, L.; Yen, Y.-R.; Zhao, Y. B.; nEXO Collaboration

    2015-02-01

    Progress on a method of barium tagging for the nEXO double beta decay experiment is reported. Absorption and emission spectra for deposits of barium atoms and ions in solid xenon matrices are presented. Excitation spectra for prominent emission lines, temperature dependence, and bleaching of the fluorescence reveal the existence of different matrix sites. A regular series of sharp lines observed in Ba+ deposits is identified with some type of barium hydride molecule. Lower limits for the fluorescence quantum efficiency of the principal Ba emission transition are reported. Under current conditions, an image of fewer than or equal to 104 Ba atoms can be obtained. Prospects for imaging single Ba atoms in solid xenon are discussed.

  4. Solvothermal synthesis and characterization of two inorganic-organic hybrid materials based on barium.

    PubMed

    Abdollahian, Yashar; Hauser, Jesse L; Rogow, David L; Oliver, Allen G; Oliver, Scott R J

    2012-10-28

    Two metal-organic frameworks containing barium were synthesized hydrothermally and investigated for their catalytic properties. Ba(2)F(2)[O(3)SC(2)H(4)SO(3)] has barium fluoride layers linked by organic 1,2-ethanedisulfonate molecules. Ba[O(3)SC(2)H(4)SO(3)] has discrete barium centers arranged in layers and connected covalently by ethanedisulfonate bridges. Thermogravimetric analysis showed that Ba(2)F(2)[O(3)SC(2)H(4)SO(3)] is stable to ca. 325 °C and Ba[O(3)SC(2)H(4)SO(3)] to ca. 375 °C. These materials expand the metal-organic frameworks available for group II metals bound to organodisulfonate linkers and are potentially useful for a range of heterogeneous acid catalysis reactions.

  5. Observation of a barium xenon exciplex within a large argon cluster.

    PubMed

    Briant, M; Gaveau, M-A; Mestdagh, J-M

    2010-07-21

    Spectroscopic measurements provide fluorescence and excitation spectra of a single barium atom codeposited with xenon atoms on argon clusters of average size approximately 2000. The spectra are studied as a function of the number of xenon atoms per cluster. The excitation spectrum with approximately 10 xenon atoms per cluster is qualitatively similar to that observed when no xenon atom is present on the cluster. It consists of two bands located on each side of the 6s6p (1)P-6s(2) (1)S resonance line of the free barium. In contrast, the fluorescence spectrum differs qualitatively since a barium-xenon exciplex is observed, which has no counterpart in xenon free clusters. In particular an emission is observed, which is redshifted by 729 cm(-1) with respect to the Ba(6s6p (1)P-6s(2) (1)S) resonance line.

  6. Oral peppermint oil is a useful antispasmodic for double-contrast barium meal examination.

    PubMed

    Mizuno, Shigeaki; Kato, Kimitoshi; Ono, Yoshiki; Yano, Kiyoshi; Kurosaka, Hanzo; Takahashi, Atsuhiko; Abeta, Hiromi; Kushiro, Toshio; Miyamoto, Syunpachi; Kurihara, Ryuichi; Hiki, Naoki; Kaminishi, Michio; Iwasaki, Ariyoshi; Arakawa, Yasuyuki

    2006-08-01

    Intraluminally administered peppermint oil (PO) is reportedly a safe and useful antispasmodic for gastroscopy, colonoscopy and double-contrast barium enema. The aim of this study was to examine the efficacy of oral PO for double-contrast barium meal examination (DCBM) without other antispasmodics. Two hundred and five randomly chosen subjects (PO group) and 215 sex- and age-matched controls were enrolled. All participants underwent DCBM. The PO group was orally administered PO and a barium suspension mixture at the start of DCBM. Radiographs were blindly evaluated for spasm and overlapping with barium-filled duodenal loops (scored 0-3, indicating none to severe). The quality of barium coating of the mucosa and overall diagnostic quality (scored 0-3, indicating not acceptable to excellent) were also evaluated. There was no significant difference in subject acceptance between PO group and controls, and no adverse effects in either group. Scores for spasm at the esophagus, lower stomach and duodenal bulb were significantly lower in the PO than in the control group (P < 0.001). Scores for overlapping at the lower stomach and duodenal bulb were significantly lower in the PO than in the control group (P < 0.05, P < 0.01, respectively). Scores for overall diagnostic quality at the esophagus, lower stomach and duodenal bulb were significantly higher in the PO than in the control group (P < 0.001). Oral PO reduces spasm of the esophagus, lower stomach and duodenal bulb, inhibits barium flow to the distal duodenum, and improves diagnostic quality without other antispasmodics. Oral PO is a safe, easy to use and effective antispasmodic for DCBM.

  7. Individual-specific transgenerational marking of fish populations based on a barium dual-isotope procedure.

    PubMed

    Huelga-Suarez, Gonzalo; Moldovan, Mariella; Garcia-Valiente, America; Garcia-Vazquez, Eva; Alonso, J Ignacio Garcia

    2012-01-03

    The present study focuses on the development and evaluation of an individual-specific transgenerational marking procedure using two enriched barium isotopes, (135)Ba and (137)Ba, mixed at a given and selectable molar ratio. The method is based on the deconvolution of the isotope patterns found in the sample into four molar contribution factors: natural xenon (Xe nat), natural barium (Ba nat), Ba135, and Ba137. The ratio of molar contributions between Ba137 and Ba135 is constant and independent of the contribution of natural barium in the sample. This procedure was tested in brown trout ( Salmo trutta ) kept in captivity. Trout were injected with three different Ba137/Ba135 isotopic signatures ca. 7 months and 7 days before spawning to compare the efficiency of the marking procedure at long and short term, respectively. The barium isotopic profiles were measured in the offspring by means of inductively coupled plasma mass spectrometry. Each of the three different isotopic signatures was unequivocally identified in the offspring in both whole eggs and larvae. For 9 month old offspring, the characteristic barium isotope signatures could also be detected in the otoliths even in the presence of a high and variable amount of barium of natural isotope abundance. In conclusion, it can be stated that the proposed dual-isotope marking is inheritable and can be detected after both long-term and short-term marking. Furthermore, the dual-isotope marking can be made individual-specific, so that it allows identification of offspring from a single individual or a group of individuals within a given fish group.

  8. Imaging assessment of the modified double contrast barium enema using carboxymethylcellulose on radiography and ultrasonography in dogs.

    PubMed

    Choi, Mihyun; Lee, Namsoon; Kim, Junyoung; Yi, Kangjae; Jung, Joohyun; Yoon, Junghee; Choi, Mincheol

    2011-01-01

    A modified double contrast barium enema using carboxymethylcellulose was evaluated in beagle dogs and compared with dogs receiving a conventional barium enema. The experimental group was divided into three groups (1, 2, and 3) and given 30 ml/kg of different volume ratios of a barium vs. carboxymethylcellulose mixture. Each group underwent sonography following radiography. The volume ratio of one part barium to three parts carboxymethylcellulose was judged to be the optimal mixture, resulting in a general distribution of contrast and bowel radiolucency on radiographs and adequate postradiography sonography. The modified barium enema using carboxymethylcellulose is useful for assessing the general morphology and mucosal layers of the colon simultaneously on radiographs and ultrasonographs.

  9. Histopathological and microanalytical study of zirconium dioxide and barium sulphate in bone cement.

    PubMed Central

    Keen, C. E.; Philip, G.; Brady, K.; Spencer, J. D.; Levison, D. A.

    1992-01-01

    AIMS: To report the appearances of zirconium dioxide and barium sulphate in interface membranes, synovium, and other tissues around joint prostheses. METHODS: Histological sections from 23 specimens were reviewed by light microscopy and polarisation. Scanning electron microscopy and x ray microanalysis were performed on routinely processed paraffin wax sections. RESULTS: Polyethylene, metals, and polymethylmethacrylate cement debris were easily recognisable. Almost all the cement remnants contained either zirconium dioxide or barium sulphate, confirmed by microanalysis. The contrast media had characteristic light microscopic appearances. Zirconium was identified in macrophages away from cement remnants. CONCLUSION: The presence of radiographic contrast media in tissues around prosthetic joints is common but not widely recognised. Images PMID:1452794

  10. ION-EXCHANGE METHOD FOR SEPARATING RADIUM FROM RADIUM-BARIUM MIXTURES

    DOEpatents

    Fuentevilla, M.E.

    1959-06-30

    An improved process is presented for separating radium from an aqueous feed solution containing radium and barium values and a complexing agent for these metals. In this process a feed solutlon containing radium and barium ions and a complexing agent for said ions ls cycled through an exchange zone in resins. The radiumenriched resin is then stripped of radium values to form a regeneration liquid, a portion of which is collected as an enriched product, the remaining portion being recycled to the exchange zone to further enrich the ion exchange resin in radium.

  11. Precipitation of Barite by Myxococcus xanthus: Possible Implications for the Biogeochemical Cycle of Barium

    PubMed Central

    González-Muñoz, Maria Teresa; Fernández-Luque, Belén; Martínez-Ruiz, Francisca; Ben Chekroun, Kaoutar; Arias, José María; Rodríguez-Gallego, Manuel; Martínez-Cañamero, Magdalena; de Linares, Concepción; Paytan, Adina

    2003-01-01

    Bacterial precipitation of barite (BaSO4) under laboratory conditions is reported for the first time. The bacterium Myxococcus xanthus was cultivated in a solid medium with a diluted solution of barium chloride. Crystallization occurred as a result of the presence of live bacteria and the bacterial metabolic activity. A phosphorous-rich amorphous phase preceded the more crystalline barite formation. These experiments may indicate the involvement of bacteria in the barium biogeochemical cycle, which is closely related to the carbon cycle. PMID:12957970

  12. Synthesis and assembly of barium-doped iron oxide nanoparticles and nanomagnets.

    PubMed

    Wu, Liheng; Shen, Bo; Sun, Shouheng

    2015-10-21

    A facile organic-phase synthesis of monodisperse barium-doped iron oxide (Ba-Fe-O) nanoparticles (NPs) is reported. The Ba-Fe-O NPs can be converted into hexagonal barium ferrite NPs at 700 °C, showing strong ferromagnetic properties with H(c) reaching 5260 Oe and M(s) at 54 emu g(-1). Moreover, the Ba-Fe-O NPs can be assembled into densely packed magnetic arrays, providing a unique model system for studying nanomagnetism and for nanomagnetic applications.

  13. The structural properties of barium cobalt hexaferrite powder prepared by a simple heat treatment method

    NASA Astrophysics Data System (ADS)

    Chauhan, Chetna; Jotania, Rajshree

    2016-05-01

    The W-type barium hexaferrite was prepared using a simple heat treatment method. The precursor was calcinated at 650°C for 3 hours and then slowly cooled to room temperature in order to obtain barium cobalt hexaferrite powder. The prepared powder was characterised by different experimental techniques like XRD, FTIR and SEM. The X-ray diffractogram of the sample shows W-and M phases. The particle size calculated by Debye Scherrer formula. The FTIR spectra of the sample was taken at room temperature by using KBr pallet method which confirms the formation of hexaferrite phase. The morphological study on the hexaferrite powder was carried out by SEM analysis.

  14. Physical Property of Magnesium Doped Barium Hexaferrite Particles By Citrate Precursor Route In Presence Of Surfactants

    SciTech Connect

    Paladiya, Snehal; Chauhan, C. C.; Jotania, R. B.

    2010-12-01

    M-type Barium Magnesium hexaferrite with the composition BaMg{sub 2}Fe{sub 10}O{sub 19} was successfully prepared with and without surfactant by using a citrate precursor route. The obtained precursors were calcined at various temperatures. The crystalline structure, phase analysis and particle size were investigated by using X-ray diffraction (XRD), Fourier Transform infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM) techniques. It is observed that the surfactant addition controls the microstructure of the formed Barium Magnesium hexaferrite particles and the type of surfactant plays a crucial role in deciding the morphology of particles.

  15. The structural properties of barium cobalt hexaferrite powder prepared by a simple heat treatment method

    SciTech Connect

    Chauhan, Chetna; Jotania, Rajshree

    2016-05-06

    The W-type barium hexaferrite was prepared using a simple heat treatment method. The precursor was calcinated at 650°C for 3 hours and then slowly cooled to room temperature in order to obtain barium cobalt hexaferrite powder. The prepared powder was characterised by different experimental techniques like XRD, FTIR and SEM. The X-ray diffractogram of the sample shows W-and M phases. The particle size calculated by Debye Scherrer formula. The FTIR spectra of the sample was taken at room temperature by using KBr pallet method which confirms the formation of hexaferrite phase. The morphological study on the hexaferrite powder was carried out by SEM analysis.

  16. Potassium, rubidium, strontium, barium, and rare-Earth concentrations in lunar rocks and separated phases.

    PubMed

    Philpotts, J A; Schnetzler, C C

    1970-01-30

    Concentrations of potassium, rubidium, strontium, barium, and rareearth elements have been determined by mass spectrometric isotope dilution for eight Apollo 11 lunar samples and for some separated phases. Potassiumn and ritbidium are at chondritic levels, strontium at 15 times, and barium and rare earths at 30 to 100 times chondritic levels. There are trace element similarities between the lunar samples and basaltic achondrites, terrestrial dredge basalts and the bulk earth. The trace element data appear to be consistent with these lunar samples being the result of limited partial fusion of some material similar to the brecciated eucrite meteorites.

  17. Physical states and properties of barium titanate films in a plane electric field

    NASA Astrophysics Data System (ADS)

    Shirokov, V. B.; Kalinchuk, V. V.; Shakhovoi, R. A.; Yuzyuk, Yu. I.

    2016-07-01

    The influence of a plane electric field on the phase states of barium titanate thin films under the conditions of forced deformation has been studied. The field dependence of a complete set of material constants has been taken in the region of the c-phase, where polarization losses are absent. The material constants are calculated using equations of the piezoelectric effect derived by linearizing the nonlinear equations of state from the phenomenological; theory for barium titanate. It has been shown that there is a critical value of the field at which the electromechanical coupling coefficient reaches a maximum.

  18. Inositol phosphates in the environment.

    PubMed Central

    Turner, Benjamin L; Papházy, Michael J; Haygarth, Philip M; McKelvie, Ian D

    2002-01-01

    The inositol phosphates are a group of organic phosphorus compounds found widely in the natural environment, but that represent the greatest gap in our understanding of the global phosphorus cycle. They exist as inositols in various states of phosphorylation (bound to between one and six phosphate groups) and isomeric forms (e.g. myo, D-chiro, scyllo, neo), although myo-inositol hexakisphosphate is by far the most prevalent form in nature. In terrestrial environments, inositol phosphates are principally derived from plants and accumulate in soils to become the dominant class of organic phosphorus compounds. Inositol phosphates are also present in large amounts in aquatic environments, where they may contribute to eutrophication. Despite the prevalence of inositol phosphates in the environment, their cycling, mobility and bioavailability are poorly understood. This is largely related to analytical difficulties associated with the extraction, separation and detection of inositol phosphates in environmental samples. This review summarizes the current knowledge of inositol phosphates in the environment and the analytical techniques currently available for their detection in environmental samples. Recent advances in technology, such as the development of suitable chromatographic and capillary electrophoresis separation techniques, should help to elucidate some of the more pertinent questions regarding inositol phosphates in the natural environment. PMID:12028785

  19. Templated, layered manganese phosphate

    DOEpatents

    Thoma, Steven G.; Bonhomme, Francois R.

    2004-08-17

    A new crystalline maganese phosphate composition having an empirical formula: O). The compound was determined to crystallize in the trigonal space group P-3c1 with a=8.8706(4) .ANG., c=26.1580(2) .ANG., and V (volume)=1783 .ANG..sup.3. The structure consists of sheets of corner sharing Mn(II)O.sub.4 and PO.sub.4 tetrahedra with layers of (H.sub.3 NCH.sub.2 CH.sub.2).sub.3 N and water molecules in-between. The pronated (H.sub.3 NCH.sub.2 CH.sub.2).sub.3 N molecules provide charge balancing for the inorganic sheets. A network of hydrogen bonds between water molecules and the inorganic sheets holds the structure together.

  20. Light weight phosphate cements

    DOEpatents

    Wagh, Arun S.; Natarajan, Ramkumar,; Kahn, David

    2010-03-09

    A sealant having a specific gravity in the range of from about 0.7 to about 1.6 for heavy oil and/or coal bed methane fields is disclosed. The sealant has a binder including an oxide or hydroxide of Al or of Fe and a phosphoric acid solution. The binder may have MgO or an oxide of Fe and/or an acid phosphate. The binder is present from about 20 to about 50% by weight of the sealant with a lightweight additive present in the range of from about 1 to about 10% by weight of said sealant, a filler, and water sufficient to provide chemically bound water present in the range of from about 9 to about 36% by weight of the sealant when set. A porous ceramic is also disclosed.

  1. 21 CFR 184.1301 - Ferric phosphate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... GRAS § 184.1301 Ferric phosphate. (a) Ferric phosphate (ferric orthophosphate, iron (III) phosphate, Fe... ferric chloride or ferric citrate. (b) The ingredient meets the specifications of the Food Chemicals...

  2. Phosphate nutrition: improving low-phosphate tolerance in crops.

    PubMed

    López-Arredondo, Damar Lizbeth; Leyva-González, Marco Antonio; González-Morales, Sandra Isabel; López-Bucio, José; Herrera-Estrella, Luis

    2014-01-01

    Phosphorus is an essential nutrient that is required for all major developmental processes and reproduction in plants. It is also a major constituent of the fertilizers required to sustain high-yield agriculture. Levels of phosphate--the only form of phosphorus that can be assimilated by plants--are suboptimal in most natural and agricultural ecosystems, and when phosphate is applied as fertilizer in soils, it is rapidly immobilized owing to fixation and microbial activity. Thus, cultivated plants use only approximately 20-30% of the applied phosphate, and the rest is lost, eventually causing water eutrophication. Recent advances in the understanding of mechanisms by which wild and cultivated species adapt to low-phosphate stress and the implementation of alternative bacterial pathways for phosphorus metabolism have started to allow the design of more effective breeding and genetic engineering strategies to produce highly phosphate-efficient crops, optimize fertilizer use, and reach agricultural sustainability with a lower environmental cost. In this review, we outline the current advances in research on the complex network of plant responses to low-phosphorus stress and discuss some strategies used to manipulate genes involved in phosphate uptake, remobilization, and metabolism to develop low-phosphate-tolerant crops, which could help in designing more efficient crops.

  3. Crystallization of calcium phosphate in polyacrylamide hydrogels containing phosphate ions

    NASA Astrophysics Data System (ADS)

    Yokoi, Taishi; Kawashita, Masakazu; Kikuta, Koichi; Ohtsuki, Chikara

    2010-08-01

    Calcium phosphate crystals were formed in polyacrylamide (PAAm) hydrogels containing phosphate ions by diffusion of calcium ions from calcium nitrate (Ca(NO 3) 2) solutions covering the gels. Changes in crystalline phases and crystal morphology of calcium phosphate, and in ion concentrations of the Ca(NO 3) 2 solutions were investigated as a function of reaction time. Single or two coexisting crystalline phases of calcium phosphate, hydroxyapatite (HAp), HAp/dicalcium phosphate dihydrate (DCPD) or octacalcium phosphate (OCP)/DCPD were formed in the gels. HAp crystals are formed near the surface of the gels. The dense HAp layer and HAp/DCPD layer prevented diffusion of calcium ions from the Ca(NO 3) 2 solution, thus formation of calcium phosphate in the gel phase was inhibited. Formation of DCPD was observed to follow the formation of OCP or HAp. The size of the OCP crystals gradually increased with reaction time, while changes in size of HAp crystals were not observed. The reaction time required for DCPD formation depended on the degree of supersaturation with respect to DCPD in the systems. DCPD formed within 1 day under high supersaturation conditions, whereas it formed at 10 days in low supersaturation conditions.

  4. Vibrational spectroscopic characterization of the phosphate mineral kulanite Ba(Fe2+,Mn2+,Mg)2(Al,Fe3+)2(PO4)3(OH)3

    NASA Astrophysics Data System (ADS)

    Frost, Ray L.; López, Andrés; Xi, Yunfei; Granja, Amanda; Scholz, Ricardo

    2013-11-01

    The mineral kulanite BaFe2Al2(PO4)3(OH)3, a barium iron aluminum phosphate, has been studied by using a combination of electron microscopy and vibrational spectroscopy. Scanning electron microscopy with EDX shows the mineral is homogenous with no other phases present. The Raman spectrum is dominated by an intense band at 1022 cm-1 assigned to the PO43- ν1 symmetric stretching mode. Low intensity Raman bands at 1076, 1110, 1146, 1182 cm-1 are attributed to the PO43 - ν3 antisymmetric stretching vibrations. The infrared spectrum shows a complex spectral profile with overlapping bands. Multiple phosphate bending vibrations supports the concept of a reduction in symmetry of the phosphate anion. Raman spectrum at 3211, 3513 and 3533 cm-1 are assigned to the stretching vibrations of the OH units. Vibrational spectroscopy enables aspects on the molecular structure of kulanite to be assessed.

  5. Growth rate controlled barium partitioning in calcite and aragonite

    NASA Astrophysics Data System (ADS)

    Goetschl, Katja Elisabeth; Mavromatis, Vasileios; Baldermann, Andre; Purgstaller, Bettina; Dietzel, Martin

    2016-04-01

    The barium (Ba) content and the Ba/Ca molar ratios in biogenic and abiotic carbonates have been widely used from the scientific community as a geochemical proxy especially in marine and early diagenetic settings. The Ba content of carbonate minerals has been earlier associated to changes in oceanic circulation that may have been caused by upwelling, changes in weathering regimes and river-runoff as well as melt water discharge. The physicochemical controls of Ba ion incorporation in the two most abundant CaCO3 polymorphs found in Earth's surface environments, i.e. calcite and aragonite, have adequately been studied only for calcite. These earlier studies (i.e. [1]) suggest that at increasing growth rate, Ba partitioning in calcite is increasing as well. In contrast, to date the effect of growth rate on the partitioning of Ba in aragonite remains questionable, despite the fact that this mineral phase is the predominant carbonate-forming polymorph in shallow marine environments. To shed light on the mechanisms controlling Ba ion uptake in carbonates in this study we performed steady-state Ba co-precipitation experiments with calcite and aragonite at 25°C. The obtained results for the partitioning of Ba in calcite are in good agreement with those reported earlier by [1], whereas those for aragonite indicate a reduction of Ba partitioning at elevated aragonite growth rates, with the partitioning coefficient value between solid and fluid to be approaching the unity. This finding is good agreement with the formation of a solid solution in the aragonite-witherite system, owing to the isostructural crystallography of the two mineral phases. Moreover, our data set provides new insights that are required for reconstructing the evolution of the Ba content of pristine marine versus diagenetically altered carbonate minerals commonly occurring in marine subfloor settings, as the thermodynamically less stable aragonite will transform to calcite enriched in Ba, whilst affecting

  6. Rapid ray motions in barium plasma clouds and auroras

    SciTech Connect

    Wescott, E.M.; Hallinan, T.J.; Stenbaek-Nielsen, H.C.; Swift, D.W.; Wallis, D.D. )

    1993-03-01

    Barium plasma clouds released at high latitudes characteristically become striated with many field-aligned rays. The rays which often resemble auroral features usually drift as a whole with the E [times] B/B[sup 2] drift of the cloud and alter position only slowly (order or tens of seconds). On two evenings in 1968, in releases from Andoya, Norway, anomalous field-aligned brightenings or emission enhancements of up to 3X were observed to move rapidly (10-20 km/s) through three different Ba[sup +] clouds. Similar effects were observed in Ba[sup +] clouds released from rockets launched from Poker Flat, Alaska: On March 21, 1973, in two Ba thermite releases and on March 22, 1980, in the Ba-shaped charge experiment Miss Peggy.' On these occasions, auroras on or near the Ba[sup +] L shell, also exhibited active rapid ray motions. This leads to the assumption that the two phenomena are related and the expectation that an explanation of the rapid ray motions in the Ba[sup +] clouds would lead to a better understanding of the physics of auroral ray motions and the auroral ionosphere. Seven possible mechanisms to produce the observed moving emission enhancements are discussed. Direct motion of an isolated Ba[sup +] ray past the other rays by E [times] B/B[sup 2] motion seems very unlikely due to the observed variations in the enhancements and the large E field required (> 500 mV/m). Compressional waves do not seem to be of sufficient amplitude or velocity. Absorption or radiation of Doppler shifted Ba[sup +] emissions by ions gyrating or moving at a few kilometers per second seems to be the most promising mechanism for producing the enhancements. The observations provide compelling evidence for the existence of transient electric fields of order 100 mV/m at altitudes as low as 200 km during active aurora with rapid ray motions. The affected regions have dimensions of order a few kilometers across B and move eastward at 10-20 km/s. 36 refs., 10 figs., 1 tab.

  7. Regeneration of barium carbonate from barium sulphide in a pilot-scale bubbling column reactor and utilization for acid mine drainage.

    PubMed

    Mulopo, J; Zvimba, J N; Swanepoel, H; Bologo, L T; Maree, J

    2012-01-01

    Batch regeneration of barium carbonate (BaCO(3)) from barium sulphide (BaS) slurries by passing CO(2) gas into a pilot-scale bubbling column reactor under ambient conditions was used to assess the technical feasibility of BaCO(3) recovery in the Alkali Barium Calcium (ABC) desalination process and its use for sulphate removal from high sulphate Acid Mine Drainage (AMD). The effect of key process parameters, such as BaS slurry concentration and CO(2) flow rate on the carbonation, as well as the extent of sulphate removal from AMD using the recovered BaCO(3) were investigated. It was observed that the carbonation reaction rate for BaCO(3) regeneration in a bubbling column reactor significantly increased with increase in carbon dioxide (CO(2)) flow rate whereas the BaS slurry content within the range 5-10% slurry content did not significantly affect the carbonation rate. The CO(2) flow rate also had an impact on the BaCO(3) morphology. The BaCO(3) recovered from the pilot-scale bubbling column reactor demonstrated effective sulphate removal ability during AMD treatment compared with commercial BaCO(3).

  8. Chromium determination in pharmaceutical grade barium sulfate by solid sampling electrothermal atomic absorption spectrometry with Zeeman-effect background correction.

    PubMed

    Bolzan, Rodrigo Cordeiro; Rodrigues, Luis Frederico; Mattos, Júlio Cezar Paz de; Dressler, Valderi Luiz; Flores, Erico Marlon de Moraes

    2007-11-15

    A procedure for chromium (Cr) determination in pharmaceutical grade barium sulfate by direct solid sampling electrothermal atomic absorption spectrometry (DSS-ET AAS) with Zeeman-effect background correction was developed. Operational conditions for the proposed procedure and the use of citric acid, ammonium phosphate, palladium and magnesium nitrate as chemical modifiers were evaluated. Pyrolysis and atomization temperatures were set at 1500 and 2400 degrees C, respectively and the use of matrix modifiers did not improve these conditions. Graphite platform presented high degradation rate, but minima changes were observed in the sensitivity or signal profile. Samples (0.3-1 mg) were weighted and introduced into the furnace using a manual solid sampling system. The linear concentration range of the calibration curve was from 100 to 1800 pg (R(2)>0.995). The characteristic mass was 7.7 pg and the limit of detection was 2.4 pg. Chromium concentration in commercial samples ranged from 0.45 to 1.06 microg g(-1) and these results were confirmed by standard addition method. The mean reproducibility was 12% (n=20 in a 3-day period) and repeatability was less than 9%. Results obtained using inductively coupled plasma optical emission spectrometry and conventional electrothermal atomic absorption spectrometry after extraction with HNO3 were around 20% lower than those obtained by the proposed procedure. It was assumed that the low results were due to incomplete extraction even using hard conditions related to temperature and pressure. The proposed procedure by DSS-ET AAS provided some advantages related to recommended pharmacopoeias methodology, as lower risks of contamination and analyte losses, higher specificity, accuracy and sensitivity, no toxic or unstable reagents are required, and calibration with aqueous standards was feasible.

  9. Structure of iron phosphate glasses modified by alkali and alkaline earth additions: neutron and x-ray diffraction studies.

    PubMed

    Bingham, P A; Barney, E R

    2012-05-02

    The structure of iron phosphate glasses modified by additions of K(2)O and BaO, with nominal molar compositions [(1 - x)(0.6P(2)O(5)-0.4Fe(2)O(3))]xMe(y)O, where x = 0-0.4 in increments of 0.1; Me=K or Ba; and y = 1 or 2, has been investigated using neutron diffraction and x-ray diffraction techniques. Fitted coordination numbers for P-O and Fe-O showed a notable change in the P-O(NBO) and P-O(BO) contributions at greater than 20 mol% modifier addition, with barium producing a markedly larger increase in P-O(NBO) contribution than potassium. Fitting of T(N)(r) and T(X)(r) provided average n(BaO) = 9 and n(KO) = 6. Iron occurs in a range of coordination sites in these glasses: ([6])Fe(2+), ([4])Fe(3+), ([5])Fe(3+) and ([6])Fe(3+). The partitioning between these sites gives average n(FeO) = 5.2-5.8, with barium-doped glasses exhibiting higher average n(FeO) than potassium-doped glasses. The stronger depolymerizing effect of Ba(2+) than K(+) on the phosphate network, coupled with its greater ionic charge and higher Me-O, Fe-O and O···O coordination numbers, explain previously observed divergences in physical properties between the barium-doped and the potassium-doped glasses.

  10. Proposed Oral Reference Dose (RfD) for Barium and Compounds (Final Report, 2004)

    EPA Science Inventory

    This document is the final report from the 2004 external peer review of the Proposed Oral Reference Dose (RfD) for Barium and Compounds, prepared by the U.S. Environmental Protection Agency (EPA), National Center for Environmental Assessment (NCEA), for the Integrated Risk...

  11. Low temperature phase barium borate: A new optical limiter in continuous wave and nano pulsed regime

    NASA Astrophysics Data System (ADS)

    Babeela, C.; Girisun, T. C. Sabari

    2015-11-01

    Low temperature phase barium borate was synthesized by hydrothermal method. XRD analysis confirms the formation of γ-BBO or hydrated barium polyborate (Ba3B6O9(OH)6) which crystallizes in monoclinic system in the P2/c space group. The molecular structure analysis shows the presence of dominant BO4 unit and the hydrated nature of material. γ-BBO exhibits sharp absorption edge at 202 nm and highly transparency in the UV-Visible-NIR region. The peak at 347 nm in the emission spectrum is due to the presence of self-trapped exciton. The third order nonlinear optical properties and limiting behavior of low temperature barium borate in both pulsed and continuous wave regime were studied. The effective 2PA absorption coefficient of γ-BBO under ns pulse excitation is estimated to be 0.38 × 10-10 m/W. The nonlinear absorption coefficient, refractive index and optical susceptibility of the material in cw regime were found to be in the order of 10-5 m W-1, 10-12 m2 W-1, 10-6 esu respectively. In both regimes, low temperature phase barium borate exhibits better optical limiting properties than high temperature phase β-BBO.

  12. Demonstrating the potential of yttrium-doped barium zirconate electrolyte for high-performance fuel cells

    NASA Astrophysics Data System (ADS)

    Bae, Kiho; Jang, Dong Young; Choi, Hyung Jong; Kim, Donghwan; Hong, Jongsup; Kim, Byung-Kook; Lee, Jong-Ho; Son, Ji-Won; Shim, Joon Hyung

    2017-02-01

    In reducing the high operating temperatures (>=800 °C) of solid-oxide fuel cells, use of protonic ceramics as an alternative electrolyte material is attractive due to their high conductivity and low activation energy in a low-temperature regime (<=600 °C). Among many protonic ceramics, yttrium-doped barium zirconate has attracted attention due to its excellent chemical stability, which is the main issue in protonic-ceramic fuel cells. However, poor sinterability of yttrium-doped barium zirconate discourages its fabrication as a thin-film electrolyte and integration on porous anode supports, both of which are essential to achieve high performance. Here we fabricate a protonic-ceramic fuel cell using a thin-film-deposited yttrium-doped barium zirconate electrolyte with no impeding grain boundaries owing to the columnar structure tightly integrated with nanogranular cathode and nanoporous anode supports, which to the best of our knowledge exhibits a record high-power output of up to an order of magnitude higher than those of other reported barium zirconate-based fuel cells.

  13. Double contrast barium meal examination - a comparison of techniques for introducing gas.

    PubMed

    James, W B; McCreath, G; Sutherland, G R; McDonald, M

    1976-01-01

    A comparison made between five techniques for introducing additional gas to the stomach for double contrast barium examination showed effervescent tablets to be associated with significant improvement in gastric mucosal coating with significantly less bubble formation. A proprietary effervescent health salt on the other hand was associated with significantly greater bubble formation.

  14. Barium borosilicate glass as a matrix for the uptake of dyes.

    PubMed

    Ramkumar, Jayshree; Chandramouleeswaran, S; Sudarsan, V; Mishra, R K; Kaushik, C P; Raj, Kanwar; Tyagi, A K

    2009-12-15

    Barium borosilicate (BBS) and sodium borosilicate (SBS) glass samples, prepared by the conventional melt-quench method, were used for the uptake of Rhodamine 6G dye from aqueous solution. The experimental conditions were optimized to get maximum uptake and was found to be 0.4 mg of dye per gram of BBS glass sample. For the same network former to modifier ratio, barium borosilicate glasses are found to have improved extent of uptake for the dye molecules from aqueous solutions compared to sodium borosilicate glasses. Based on 29Si MAS NMR studies on these glasses, it is inferred that significantly higher number of non-bridging oxygen atoms present in barium borosilicate glasses compared to sodium borosilicate glasses is responsible for its improved uptake of Rhodamine 6G dye. 11B MAS NMR studies have confirmed the simultaneous existence of boron in BO3 and BO4 configurations in both barium borosilicate and sodium borosilicate glasses. The luminescence studies have established that the dye molecule is incorporated into the glass matrix through ion exchange mechanism by replacing the exchangeable ions like Na+/Ba2+ attached with the non-bridging oxygen atoms present in the glass.

  15. Deposition barium titanate (BaTiO3) doped lanthanum with chemical solution deposition

    NASA Astrophysics Data System (ADS)

    Iriani, Y.; Jamaludin, A.; Nurhadi, N.

    2016-11-01

    Deposition of Barium Titanate (BaTiO3) thin films used Chemical Solution Deposition (CSD) method and prepared with spin coater. BaTiO3 is doped with lanthanum, 1%, 2%, and 3%. The thermal process use annealing temperature 900°C and holding time for 3 hours. The result of characterization with x-ray diffraction (XRD) equipment show that the addition of La3+ doped on Barium Titanate caused the change of angle diffraction.The result of refine with GSAS software shows that lanthanum have been included in the structure of BaTiO3. Increasing mol dopant La3+ cause lattice parameter and crystal volume become smaller. Characterization result using Scanning Electron Microscopy (SEM) equipment show that grain size (grain size) become smaller with increasing mole dopant (x) La3+. The result of characterization using Sawyer Tower methods show that all the samples (Barium Titanante and Barium Titanate doped lanthanum) are ferroelectric material. Increasing of mole dopant La3+ cause smaller coercive field and remanent polarization increases.

  16. Barium versus Nonbarium Stimuli: Differences in Taste Intensity, Chemesthesis, and Swallowing Behavior in Healthy Adult Women

    ERIC Educational Resources Information Center

    Nagy, Ahmed; Steele, Catriona M.; Pelletier, Cathy A.

    2014-01-01

    Purpose: The authors examined the impact of barium on the perceived taste intensity of 7 different liquid tastant stimuli and the modulatory effect that these differences in perceived taste intensity have on swallowing behaviors. Method: Participants were 80 healthy women, stratified by age group (<40; >60) and genetic taste status…

  17. Surface composition and barium evaporation rate of ``pedigreed'' impregnated tungsten dispenser cathodes during accelerated life testing

    NASA Astrophysics Data System (ADS)

    Tomich, D. H.; Mescher, J. A.; Grant, J. T.

    1987-03-01

    A study has been made of the surface composition and barium evaporation rate of "pedigreed" impregnated tungsten dispenser cathodes. The effect of air exposure on coated cathodes was examined and was found to have no significant effect on barium evaporation rate although in some cases longer reactivation times were required. No changes in surface topography were apparent following air exposure and reactivation. Life testing was done at 100°C above the typical operating temperature for the cathode, where the typical operating temperature was taken to be 950°C for coated cathodes and 1050°C for uncoated cathodes. The cathodes were examined at different stages of life testing, up to 1200 h. Significant decreases in barium evaporation rates were found after as few as 500 h of life testing. After 1000 h the evaporation rate had decreased more than an order of magnitude. Changes in surface composition were also found. The effects of tungsten particle size, used in manufacture of the billet, on barium evaporation rate were also studied but no correlation was found.

  18. Inconceivable Hypokalemia: A Case Report of Acute Severe Barium Chloride Poisoning

    PubMed Central

    Man, Yanru; Shi, Xiaoyuan; Zhu, Jun; Pan, Hang; Qin, Qin

    2016-01-01

    Barium is a heavy divalent alkaline earth metal that has been known as a muscle poison. Barium can cause human toxicity, which may lead to significant hypokalemia and have serious consequences. This paper reports a case of unprecedented barium intoxication in which the patient, who suffered from depression, swallowed at least 3.0 g barium chloride to commit suicide. On admission, the patient presented with nausea, vomiting, stomach burning feeling, dizziness, and weakness. Emergency biochemical testing showed that the patient was suffering from severe hypokalemia (K+ 1.7 mmol/L). His electrocardiogram (ECG) prompted atrioventricular blocking, ventricular tachycardia, prolongation of PR interval, ST segment depression with U waves, and T wave inversion. Intravenous potassium supplements were given immediately to correct hypokalemia and regular monitoring of vital signs and fluid balance was arranged. After all-out rescue of our hospital personnel, the condition of the patient is currently stable and he is gradually recovering. This case exemplifies the weaknesses of the management of toxic substances and the lack of mental health education for young people. We hope to get more attention for the supervision of toxic substances and the healthy development of young people. PMID:27840643

  19. Demonstrating the potential of yttrium-doped barium zirconate electrolyte for high-performance fuel cells.

    PubMed

    Bae, Kiho; Jang, Dong Young; Choi, Hyung Jong; Kim, Donghwan; Hong, Jongsup; Kim, Byung-Kook; Lee, Jong-Ho; Son, Ji-Won; Shim, Joon Hyung

    2017-02-23

    In reducing the high operating temperatures (≥800 °C) of solid-oxide fuel cells, use of protonic ceramics as an alternative electrolyte material is attractive due to their high conductivity and low activation energy in a low-temperature regime (≤600 °C). Among many protonic ceramics, yttrium-doped barium zirconate has attracted attention due to its excellent chemical stability, which is the main issue in protonic-ceramic fuel cells. However, poor sinterability of yttrium-doped barium zirconate discourages its fabrication as a thin-film electrolyte and integration on porous anode supports, both of which are essential to achieve high performance. Here we fabricate a protonic-ceramic fuel cell using a thin-film-deposited yttrium-doped barium zirconate electrolyte with no impeding grain boundaries owing to the columnar structure tightly integrated with nanogranular cathode and nanoporous anode supports, which to the best of our knowledge exhibits a record high-power output of up to an order of magnitude higher than those of other reported barium zirconate-based fuel cells.

  20. Growth and optical property characterization of textured barium titanate thin films for photonic applications

    NASA Astrophysics Data System (ADS)

    Dicken, Matthew J.; Diest, Kenneth; Park, Young-Bae; Atwater, Harry A.

    2007-03-01

    We have investigated the growth of barium titanate thin films on bulk crystalline and amorphous substrates utilizing biaxially oriented template layers. Ion beam-assisted deposition was used to grow thin, biaxially textured, magnesium oxide template layers on amorphous and silicon substrates. Growth of highly oriented barium titanate films on these template layers was achieved by molecular beam epitaxy using a layer-by-layer growth process. Barium titanate thin films were grown in molecular oxygen and in the presence of oxygen radicals produced by a 300 W radio frequency plasma. We used X-ray and in situ reflection high-energy electron diffraction (RHEED) to analyze the structural properties and show the predominantly c-oriented grains in the films. Variable angle spectroscopic ellipsometry was used to analyze and compare the optical properties of the thin films grown with and without oxygen plasma. We have shown that optical quality barium titanate thin films, which show bulk crystal-like properties, can be grown on any substrate through the use of biaxially oriented magnesium oxide template layers.

  1. Effects of barium and cadmium on the population development of the marine nematode Rhabditis (Pellioditis) marina.

    PubMed

    Lira, V F; Santos, G A P; Derycke, S; Larrazabal, M E L; Fonsêca-Genevois, V G; Moens, T

    2011-10-01

    Offshore oil and gas drilling often involves the use of fluids containing barium and traces of other heavy metals. These may affect the environment, but information on their toxicity to benthic biota remains scant. Here, we present results of a 10-day bioassay with the marine nematode Rhabditis (Pellioditis) marina at different loads of barium (0-10 ,000 ppm nominal concentrations) and cadmium (0-12 ppm) in the range of concentrations reported from drilling-impacted sediments. Barium did not affect the fitness and population development of R. (P.) marina at concentrations up to 300 ppm, but did cause a decrease in population abundance and an increase in development time from concentrations of 400-2000 ppm onwards. Increased mortality occurred at 4800 ppm Ba. For cadmium, LOEC and EC₅₀ values for total population abundance were 2.95 and 8.82 ppm, respectively. Cd concentrations as low as 2.40 to 2.68 caused a decrease in the abundance of adult nematodes, indicating that assays covering more generations would likely demonstrate yet more pronounced population-level effects. Our results indicate that oil and gas drilling activities may potentially have important implications for the meiobenthos through the toxicity of barium and associated metals like cadmium. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. A surface-chemistry study of barium ferrite nanoplates with DBSa-modified surfaces

    NASA Astrophysics Data System (ADS)

    Lisjak, Darja; Ovtar, Simona; Kovač, Janez; Gregoratti, Luca; Aleman, Belen; Amati, Matteo; Fanetti, Mattia; Makovec, Darko

    2014-06-01

    Barium ferrite (BaFe12O19) is a ferrimagnetic oxide with a high magnetocrystalline anisotropy that can be exploited in magnetically aligned ceramics or films for self-biased magnetic applications. Magnetic alignment of the films can be achieved by the directed assembly of barium ferrite nanoplates. In this investigation the nanoplates were synthesized hydrothermally and suspended in 1-butanol using dodecylbenzene sulphonic acid (DBSa) as a surfactant. They were then deposited in an electric or magnetic field on flat substrates and exhibited a significant preferential alignment in the plane of the substrate, allowing a differentiation between the analysis of their basal and side planes using scanning photoelectron microscopy with a lateral resolution down to 100 nm. The surface chemistry of the nanoplates was additionally studied with X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry. For a comparison, bare barium ferrite nanoplates were also analyzed after decomposing the DBSa at 460 °C. The deviation of the surface chemistry from the stoichiometric composition was observed and the adsorption of the DBSa molecules on the nanoplates was confirmed with all three methods. Different types of bonding (physi- or chemisorption) were possible and considered with respect to the assembly of the barium ferrite nanoplates into anisotropic magnetic films.

  3. Preparation and characterization of Fe-Mn-doped Barium Hexaferrite permanent magnet

    NASA Astrophysics Data System (ADS)

    Kurniawan, C.; Nainggolan, M. M.; Sebayang, K.; Ginting, M.; Sebayang, P.

    2017-04-01

    Barium Hexaferrite-based permanent magnets (BaFe12O19) was known for its high magnetic anisotropy and suitability in broad applications. Some dopants and atomic substitutions have been utilized to improve its properties for special purposes. In this paper, the Fe-Mn system was used as a dopant for preparing Fe-Mn-doped barium hexaferrite permanent magnet using mechanical alloying method. The physical properties of the samples, such as bulk density, and porosity were examined to study the effect of the dopant. In addition, the crystal structure and magnetic properties of the samples were analyzed using X-Ray Diffractometer (XRD) and Vibrating Sample Magnetometer (VSM), respectively. It is found that the addition of Fe-Mn into barium hexaferrite contributes on the appearance of minor phases such as iron oxide-based magnetite and hematite. In addition, the XRD peak shifted to smaller angle which is likely due to Mn ion substitution and lattice strain within the hexaferrite crystal. It is also observed that the magnetic properties of Fe-Mn-doped barium hexaferrite was inferior to that of the undoped samples. It means that the formation of magnetite and hematite from Fe-Mn dopant during the sintering process is dominant and results to the reduction of hard magnetic properties of the samples.

  4. Barium in southern california coastal waters: a potential indicator of marine drilling contamination.

    PubMed

    Chow, T J

    1976-07-02

    The present barium content of Southern California coastal waters was determined to be 11 to 22 micrograms per kilogram of seawater. These values may be used as base-line concentrations to monitor marine contamination during future off-shore oil and gas explorations.

  5. Structural and luminescent studies on nanosized cerium doped strontium barium niobate

    NASA Astrophysics Data System (ADS)

    John, Nuja; Nandakumar, K.

    2017-06-01

    The nanosized cerium doped Strontium Barium Niobate ceramic powder system have been synthesized by sol-gel technique. The X-ray diffraction measurement confirmed the structure of cerium doped Strontium Barium Niobate ceramic powder system. The absorption peaks were analysed by FTIR spectroscopy. Particle morphology and size of the powder were examined using SEM and TEM. Crystal quality and structure were also examined by micro raman spectra. The transmission electron microscopy image of cerium doped Strontium Barium Niobate nano powder system consist of particles with average size of 20 nm. A band gap of the system was measured by optical absorption spectra. Photoluminescence data were recorded at room temperature. The emission peaks were detected under excitation at 305 nm wavelength. The peaks are assigned to the cerium electron transition from lowest 5d level to 2F5/2 and 2F7/2 of 4f, respectively. The decay time were also measured for cerium doped Strontium Barium Niobate powder system.

  6. Thermochemical process for the production of hydrogen using chromium and barium compound

    DOEpatents

    Bamberger, Carlos E.; Richardson, Donald M.

    1977-01-25

    Hydrogen is produced by a closed cyclic process involving the reduction and oxidation of chromium compounds by barium hydroxide and the hydrolytic disproportionation of Ba.sub.2 CrO.sub.4 and Ba.sub.3 (CrO.sub.4).sub.2.

  7. High quality transparent conductive Ag-based barium stannate multilayer flexible thin films.

    PubMed

    Wu, Muying; Yu, Shihui; He, Lin; Yang, Lei; Zhang, Weifeng

    2017-12-01

    Transparent conductive multilayer thin films of silver (Ag)-embedded barium stannate (BaSnO3) structures have been deposited onto flexible polycarbonate substrates by magnetron sputtering at room temperature to develop an indium free transparent flexible electrode. The effect of thicknesses of Ag mid-layer and barium stannate layers on optical and electrical properties were investigated, and the mechanisms of conduction and transmittance were discussed. The highest value of figure of merit is 25.5 × 10(-3) Ω(-1) for the BaSnO3/Ag/BaSnO3 multilayer flexible thin films with 9 nm thick silver mid-layer and 50 nm thick barium stannate layers, while the average optical transmittance in the visible range from 380 to 780 nm is above 87%, the resistivity is 9.66 × 10(-5) Ω · cm, and the sheet resistance is 9.89 Ω/sq. The change rate of resistivity is under 10% after repeated bending of the multilayer flexible thin films. These results indicate that Ag-based barium stannate multilayer flexible thin films can be used as transparent flexible electrodes in various flexible optoelectronic devices.

  8. Distribution and source of barium in ground water at Cattaraugus Indian Reservation, southwestern New York

    USGS Publications Warehouse

    Moore, R.B.; Staubitz, W.W.

    1984-01-01

    High concentrations of dissolved barium have been found in ground water from bedrock wells on the Seneca Nation of Indians Reservation on Cattaraugus Creek in southwestern New York. Concentrations in 1982 were as high as 23.0 milligrams per liter , the highest found reported from any natural ground-water system in the world. The highest concentrations are in a bedrock aquifer and in small lenses of saturated gravel between bedrock and the overlying till. The bedrock aquifer is partly confined by silt, clay, and till. The high barium concentrations are attributed to dissolution of the mineral barite (BaSO4), which is present in the bedrock and possibly in overlying silt, clay, or till. The dissolution of barite seems to be controlled by action of sulfate-reducing bacteria, which alter the BaSO4 equilibrium by removing sulfate ions and permitting additional barite to dissolve. Ground water from the surficial, unconsolidated deposits and surface water in streams contain little or no barium. Because barium is chemically similar to calcium, it probably could be removed by cation exchange or treatments similar to those used for water softening. (USGS)

  9. Co-Ti co-substitution of M-type hexagonal barium ferrite

    NASA Astrophysics Data System (ADS)

    Li, Jie; Zhang, Huaiwu; Liu, Yinong; Liao, Yulong; Ma, Guokun; Yang, Hong

    2015-04-01

    This paper reports a study of Co-Ti equiatomic co-substitution of M-type hexagonal barium ferrites Ba(CoTi)xFe12-2xO19, with the objective to adjust coercivity to meet different application requirements. The ferrites, with x = 0.00-1.30, all exhibited the single-phase M-type barium ferrite structure. At x = 1.30, the saturation magnetization (MS) decreased by 27.7% to 47.5 Am2 kg-1 and the coercivity (HC) decreased from 4047 to 171 Oe, providing a wide control range of coercivity. Complex magnetic permeability (μ‧ and μ″) was measured to be μ‧max = 25 and μ″max = 1.5 (at 10 MHz). The value of μ‧ is much higher than that of un-doped barium ferrite (x = 0.00). Co-Ti substitution reduced the coercivity whilst increased magnetic permeability. These improvements in magnetic properties are attributed to Co and Ti occupancies at different sites in the barium ferrite crystalline structure. Substitution is preferred at 4f2, 2b and 2a sites at x < 0.50, but 2a and 4f1 sites at x < 1.15. In addition, the bulk density (ρ) of the sintered compound was found to increase with increasing Co-Ti substitution.

  10. Dietary intake of barium, bismuth, chromium, lithium, and strontium in a Spanish population (Canary Islands, Spain).

    PubMed

    González-Weller, Dailos; Rubio, Carmen; Gutiérrez, Ángel José; González, Gara Luis; Caballero Mesa, José María; Revert Gironés, Consuelo; Burgos Ojeda, Antonio; Hardisson, Arturo

    2013-12-01

    The aim of this study was to analyze barium, bismuth, chromium, lithium, and strontium contents in food and beverages consumed by the population of the Canary Islands (Spain) as well as determine dietary intake of these metals in the archipelago as a whole and in its individual islands. To this end, 440 samples were analyzed by ICP-OES and GFAAS. Barium concentrations ranged from 5.210 ± 2.117 mg/kg in nuts to 0.035 ± 0.043 mg/L in water. Viscera exhibited the highest levels of bismuth (38.07 ± 36.80 mg/kg). The cold meat and sausages group stood out for its high chromium concentrations (0.494 ± 0.257 mg/kg). The highest concentration of lithium and strontium came out in nuts (8.761 ± 5.368 mg/kg and 9.759 ± 5.181 mg/kg, respectively). The total intakes of barium, bismuth, chromium, lithium, and strontium were 0.685, 1.274, 0.087, 3.674, and 1.923 mg/day, respectively. Cereals turned out to contribute most to the dietary intake of barium, bismuth, chromium, and lithium in the Canary Islands, while fruit contributes most to the strontium intake. We also performed a metal intake study by age and sex of the population and compared the outcome with data from other regions, both national and international.

  11. Barium versus Nonbarium Stimuli: Differences in Taste Intensity, Chemesthesis, and Swallowing Behavior in Healthy Adult Women

    ERIC Educational Resources Information Center

    Nagy, Ahmed; Steele, Catriona M.; Pelletier, Cathy A.

    2014-01-01

    Purpose: The authors examined the impact of barium on the perceived taste intensity of 7 different liquid tastant stimuli and the modulatory effect that these differences in perceived taste intensity have on swallowing behaviors. Method: Participants were 80 healthy women, stratified by age group (<40; >60) and genetic taste status…

  12. Assessment of Barium Sulphate Formation and Inhibition at Surfaces with Synchrotron X-ray Diffraction (SXRD)

    SciTech Connect

    E Mavredaki; A Neville; K Sorbie

    2011-12-31

    The precipitation of barium sulphate from aqueous supersaturated solutions is a well-known problem in the oil industry often referred to as 'scaling'. The formation and growth of barite on surfaces during the oil extraction process can result in malfunctions within the oil facilities and serious damage to the equipment. The formation of barium sulphate at surfaces remains an important topic of research with the focus being on understanding the mechanisms of formation and means of control. In situ synchrotron X-ray diffraction (SXRD) was used to investigate the formation of barium sulphate on a stainless steel surface. The effect of Poly-phosphinocarboxylic acid (PPCA) and Diethylenetriamine-penta-methylenephosphonic acid (DETPMP) which are two commercial inhibitors for barium sulphate was examined. The in situ SXRD measurements allowed the identification of the crystal faces of the deposited barite in the absence and presence of the two inhibitors. The preferential effect of the inhibitors on some crystal planes is reported and the practical significance discussed.

  13. Model NSR catalysts: Fabrication and reactivity of barium oxide layers on Cu(1 1 1)

    NASA Astrophysics Data System (ADS)

    Tsami, A.; Grillo, F.; Bowker, M.; Nix, R. M.

    2006-09-01

    The growth of barium oxide on a Cu(1 1 1) substrate, formed by the deposition of barium and its subsequent oxidation, yields stable BaO films which expose predominantly the BaO(1 0 0) surface. The interaction of the oxide films with common components of motor-vehicle exhaust gases (CO 2, H 2O, NO x) has been studied using surface analytical techniques, including X-ray photoelectron spectroscopy (XPS), temperature programmed desorption (TPD) and reflection IR spectroscopy (RAIRS). The spectroscopic identification of Ba(OH) 2, BaCO 3 and Ba(NO 2) 2 phases is discussed, and the relative stabilities and decomposition mechanisms of these materials when supported on Cu(1 1 1) is revealed by a combination of TPD and XPS. BaO is shown to be resistant to reaction with pure NO and NO/O 2 mixtures, but exposure to NO 2 leads to the rapid formation of barium nitrite. The formation of the nitrite is proposed to be the first-step in the production of barium nitrate, which has previously been shown to be the main phase involved in NO x storage and reduction (NSR) catalysis.

  14. Demonstrating the potential of yttrium-doped barium zirconate electrolyte for high-performance fuel cells

    PubMed Central

    Bae, Kiho; Jang, Dong Young; Choi, Hyung Jong; Kim, Donghwan; Hong, Jongsup; Kim, Byung-Kook; Lee, Jong-Ho; Son, Ji-Won; Shim, Joon Hyung

    2017-01-01

    In reducing the high operating temperatures (≥800 °C) of solid-oxide fuel cells, use of protonic ceramics as an alternative electrolyte material is attractive due to their high conductivity and low activation energy in a low-temperature regime (≤600 °C). Among many protonic ceramics, yttrium-doped barium zirconate has attracted attention due to its excellent chemical stability, which is the main issue in protonic-ceramic fuel cells. However, poor sinterability of yttrium-doped barium zirconate discourages its fabrication as a thin-film electrolyte and integration on porous anode supports, both of which are essential to achieve high performance. Here we fabricate a protonic-ceramic fuel cell using a thin-film-deposited yttrium-doped barium zirconate electrolyte with no impeding grain boundaries owing to the columnar structure tightly integrated with nanogranular cathode and nanoporous anode supports, which to the best of our knowledge exhibits a record high-power output of up to an order of magnitude higher than those of other reported barium zirconate-based fuel cells. PMID:28230080

  15. [Measurement of the absorption coefficient of barium using cavity ringdown spectroscopy].

    PubMed

    Zhao, H; Liu, X; Zhan, M

    2001-06-01

    An apparatus for cavity ringdown spectroscopy was constructed and used for atomic absorption measurement. The transition probability for 6s6p1P1<--6s6s1S0 transition of barium atoms was obtained in the self-made apparatus. The relation between atomic absorption coefficient and atomic oven temperature was also analysed.

  16. Periodate salts as pyrotechnic oxidizers: development of barium- and perchlorate-free incendiary formulations.

    PubMed

    Moretti, Jared D; Sabatini, Jesse J; Chen, Gary

    2012-07-09

    In a flash: pyrotechnic incendiary formulations with good stabilities toward various ignition stimuli have been developed without the need for barium or perchlorate oxidizers. KIO(4) and NaIO(4) were introduced as pyrotechnic oxidizers and exhibited excellent pyrotechnic performance. The periodate salts may garner widespread use in military and civilian fireworks because of their low hygroscopicities and high chemical reactivities.

  17. Use of barium-strontium carbonatite for flux welding and surfacing of mining machines

    NASA Astrophysics Data System (ADS)

    Kryukov, R. E.; Kozyrev, N. A.; Usoltsev, A. A.

    2017-09-01

    The results of application of barium-strontium carbonatite for modifying and refining iron-carbon alloys, used for welding and surfacing in ore mining and smelting industry, are generalized. The technology of manufacturing a flux additive containing 70 % of barium-strontium carbonatite and 30 % of liquid glass is proposed. Several compositions of welding fluxes based on silicomanganese slag were tested. The flux additive was introduced in an amount of 1, 3, 5 %. Technological features of welding with the application of the examined fluxes are determined. X-ray spectral analysis of the chemical composition of examined fluxes, slag crusts and weld metal was carried out, as well as metallographic investigations of welded joints. The principal possibility of applying barium-strontium carbonatite as a refining and gas-protective additive for welding fluxes is shown. The use of barium-strontium carbonatite reduces the contamination of the weld seam with nonmetallic inclusions: non-deforming silicates, spot oxides and brittle silicates, and increases the desulfurizing capacity of welding fluxes.

  18. Multipronged mapping to the dynamics of a barium atom deposited on argon clusters.

    PubMed

    Awali, S; Gaveau, M-A; Briant, M; Mestdagh, J-M; Soep, B; Gobert, O; Maksimenka, R; Poisson, L

    2016-11-30

    The dynamics of an electronically excited barium atom deposited at the surface of an Ar≈500 cluster was explored in a multipronged approach which associates information from frequency-resolved nanosecond experiments and information from femtosecond time-resolved experiments. In both types of experiments, the dynamics is monitored by photoelectron and photoion spectroscopy.

  19. Dynamics of highly excited barium atoms deposited on large argon clusters. I. General trends.

    PubMed

    Masson, A; Poisson, L; Gaveau, M-A; Soep, B; Mestdagh, J-M; Mazet, V; Spiegelman, F

    2010-08-07

    Ba(Ar)(approximately 750) clusters were generated by associating the supersonic expansion and the pick-up techniques. A femtosecond pump (266.3 nm)-probe (792 or 399.2 nm) experiment was performed to document the dynamics of electronically excited barium within the very multidimensional environment of the argon cluster. Barium was excited in the vicinity of the 6s9p (1)P state and probed by ionization. The velocity imaging technique was used to monitor the energy distribution of photoelectrons and photoions as a function of the delay time between the pump and the probe pulses. A complex dynamics was revealed, which can be interpreted as a sequence/superposition of elementary processes, one of which is the ejection of barium out of the cluster. The latter has an efficiency, which starts increasing 5 ps after the pump pulse, the largest ejection probability being at 10 ps. The ejection process lasts at a very long time, up to 60 ps. A competing process is the partial solvation of barium in low lying electronic states. Both processes are preceded by a complex electronic relaxation, which is not fully unraveled here, the present paper being the first one in a series.

  20. Magnetic studies of cobalt doped barium hexaferrite nanoparticles prepared by modified sol-gel method

    NASA Astrophysics Data System (ADS)

    Shalini, M. Govindaraj; Sahoo, Subasa C.

    2016-05-01

    M-type barium hexaferrite (BaFe12O19) and cobalt doped barium hexaferrite (BaFe11CoO19) nanopowders were synthesized by modified sol-gel auto-combustion technique and were annealed at 900°C in air for 4 hours. The annealed powders were studied in the present work and X-ray diffraction studies showed pure phase formation after annealing. The average grain size in the nanopowder sample was decreased after doping. Magnetization value of 60 emu/g was observed at 300K for the barium hexaferrite and was reduced to 54 emu/g after doping. The coercivity of 5586 Oe was observed at 300K for the undoped sample and was found to be decreased in the doped sample. As the measurement temperature was decreased from 300K to 60K, magnetization value was increased in both the samples compared to those at 300K. The coercivity of the undoped sample was found to decrease whereas it was increased for the doped sample at 60K. The observed magnetic properties may be understood on the basis of modified exchange interaction and anisotropy in the doped sample compared to that of pure barium hexaferrite.

  1. Effect of additions of praseodymium and bismuth oxides on the properties of barium hexaferrites

    SciTech Connect

    Kirichok, P.P.; Garmash, V.Y.; Verezhak, O.F.; Voronina, N.B.

    1985-08-01

    Among oxide permanent magnets, of greatest practical interest are those made of barium hexaferrite. Because of its high constant of uniaxial anisotropy, a barium ferrite can be employed for producing permanent magnets of large coercive force. The formation of important technical properties in barium ferrites is strongly affected by their production technology, in particular, the addition of oxides, such as those or bismuth and some rare-earth elements. The goal of this work was to study the effect of bismuth and praseodymium on the parameters of the static hysteresis loop, magnetic microstructure, and electronic configuration of iron ions in the BaO.nFe/sub 2/O/sub 3/ (5.0 less than or equal tonless than or equal to6.0) system. It is determined that the changes induced in the crystallostructural parameters, magnetic microstructure, and electronic spectrum of a barium ferrite by the addition of praseodymium and bismuth oxides to the ferrite powder charge control to a large extent the formation of the magnetic energy level.

  2. Proposed Oral Reference Dose (RfD) for Barium and Compounds (Final Report, 2004)

    EPA Science Inventory

    This document is the final report from the 2004 external peer review of the Proposed Oral Reference Dose (RfD) for Barium and Compounds, prepared by the U.S. Environmental Protection Agency (EPA), National Center for Environmental Assessment (NCEA), for the Integrated Risk...

  3. Magnetic studies of cobalt doped barium hexaferrite nanoparticles prepared by modified sol-gel method

    SciTech Connect

    Shalini, M. Govindaraj; Sahoo, Subasa C.

    2016-05-06

    M-type barium hexaferrite (BaFe{sub 12}O{sub 19}) and cobalt doped barium hexaferrite (BaFe{sub 11}CoO{sub 19}) nanopowders were synthesized by modified sol-gel auto-combustion technique and were annealed at 900°C in air for 4 hours. The annealed powders were studied in the present work and X-ray diffraction studies showed pure phase formation after annealing. The average grain size in the nanopowder sample was decreased after doping. Magnetization value of 60 emu/g was observed at 300 K for the barium hexaferrite and was reduced to 54 emu/g after doping. The coercivity of 5586 Oe was observed at 300 K for the undoped sample and was found to be decreased in the doped sample. As the measurement temperature was decreased from 300 K to 60 K, magnetization value was increased in both the samples compared to those at 300 K. The coercivity of the undoped sample was found to decrease whereas it was increased for the doped sample at 60 K. The observed magnetic properties may be understood on the basis of modified exchange interaction and anisotropy in the doped sample compared to that of pure barium hexaferrite.

  4. Mass barium carbonate poisoning with fatal outcome, lessons learned: a case series

    PubMed Central

    2009-01-01

    Introduction Barium, a heavy divalent alkaline metal, has long been known to cause human toxicity. The common mode is accidental ingestion and the common compound is Barium carbonate. Here we report an incident of food poisoning in 27 law enforcement personnel with rapidly developing sequelae and a high mortality due to ingestion of Barium carbonate contaminated flour. Case presentation One midnight, 27 adult males were rushed to emergency department of Chittagong Medical College Hospital with abdominal pain, vomiting, loose motion, cramps and generalized paraesthesia. The ailment started 1-2 hours after Iftar (evening meal to break day long fast during Ramadan) which included fried vegetables coated with a flour paste. On admission, twenty of them were restless, agitated. 22 reported weakness of limbs and were unable to walk. 10 had hypotension. 22 had rapid and shallow respiration. 5 had carpopedal spasm. Different grades of limb weakness were noted with loss of tendon jerks. Ten (N12) patients had hypokalaemia, three had hypoglycaemia, 4 patients had high creatine kinase. ECG showed flat ST with U waves in 4 patients. Potassium containing intravenous fluid and Oxygen was administered. Due to limited availability of mechanical ventilators patients were put on artificial respiration using Ambu bag; manually maintained by doctors, paramedics and attendants. Four patients were transferred to another hospital for mechanical ventilation. A total of 12 patients died over next 16 hours, 4 within 3 hrs. Other patients gradually improved. Chemical analysis of the vomitus, blood and flour used for preparation of meal revealed the presence of Barium. It was assumed that the flour was contaminated with the similar looking Barium carbonate powder which was kept in the kitchen as a rodenticide. Conclusion This event exemplifies the weakness of usual health care facility in resource poor settings to cope with this kind of massive poisoning event. The multiple reported

  5. Mass barium carbonate poisoning with fatal outcome, lessons learned: a case series

    PubMed Central

    2009-01-01

    Introduction Barium, a heavy divalent alkaline metal, has long been known to cause human toxicity. The common mode is accidental ingestion and the common compound is Barium carbonate. Here we report an incident of food poisoning in 27 law enforcement personnel with rapidly developing sequelae and a high mortality due to ingestion of Barium carbonate contaminated flour. Case presentation One midnight, 27 adult males were rushed to emergency department of Chittagong Medical College Hospital with abdominal pain, vomiting, loose motion, cramps and generalized paraesthesia. The ailment started 1-2 hours after Iftar (evening meal to break day long fast during Ramadan) which included fried vegetables coated with a flour paste. On admission, twenty of them were restless, agitated. 22 reported weakness of limbs and were unable to walk. 10 had hypotension. 22 had rapid and shallow respiration. 5 had carpopedal spasm. Different grades of limb weakness were noted with loss of tendon jerks. Ten (N12) patients had hypokalaemia, three had hypoglycaemia, 4 patients had high creatine kinase. Electrocardiogram showed flat ST with U waves in 4 patients. Potassium containing intravenous fluid and Oxygen was administered. Due to limited availability of mechanical ventilators patients were put on artificial respiration using Ambu bag; manually maintained by doctors, paramedics and attendants. Four patients were transferred to another hospital for mechanical ventilation. A total of 12 patients died over next 16 hours, 4 within 3 hrs. Other patients gradually improved. Chemical analysis of the vomitus, blood and flour used for preparation of meal revealed the presence of Barium. It was assumed that the flour was contaminated with the similar looking Barium carbonate powder which was kept in the kitchen as a rodenticide. Conclusion This event exemplifies the weakness of usual health care facility in resource poor settings to cope with this kind of massive poisoning event. The multiple

  6. 1,2,4-Diazaphospholide complexes of barium: mechanism of formation and crystallographic characterization.

    PubMed

    Pi, Chengfu; Wan, Li; Liu, Weiping; Pan, Zaifu; Wu, Haoyu; Wang, Yunhua; Zheng, Wenjun; Weng, Linhong; Chen, Zhenxia; Wu, Limin

    2009-04-06

    A number of barium 1,2,4-diazaphospholide (dp(-)) complexes have been prepared by protonolysis of barium bis[bis(trimethylsilyl)]amide (Ba[N(SiMe(3))(2)](2)(THF)(2)) and the corresponding 1,2,4-diazaphospholes. The bis(3,5-diphenyl-1,2,4-diazaphospholide)-tetrakis(tetrahydrofuran)barium [eta(2)(N,N)-3,5-Ph(2)dp)(2)Ba(THF)(4)] (1) and bis(3,5-diphenyl-1,2,4-diazaphospholide)-tetrakis(dimethylsulfoxide)barium [eta(2)(N,N)-3,5-Ph(2)dp)(2)Ba(DMSO)(4)] (2) were prepared by the reactions of Ba[N(SiMe(3))(2)](2)(THF)(2) and 3,5-diphenyl-1,2,4-diazaphosphole (H[3,5-Ph(2)dp]) in tetrahydrofuran (THF) or dimethylsulfoxide (DMSO), respectively, while the bis(3,5-disubstituted-1,2,4-diazaphospholide)-(18-crown-6) barium complexes [trans-eta(2)(N,N)-dp)(2)Ba(18-crown-6)] (3), [cis-eta(2)(N,N)-tBu(2)dp)(2)Ba(18-crown-6)] (4), [trans-eta(2)(N,N)-tBu(2)dp)(2)Ba(18-crown-6)] (5), [cis-eta(2)(N,N)-Ph(2)dp)(2)Ba(18-crown-6)] (6), and [trans-eta(2)(N,N)-Ph(2)dp)(2)Ba(18-crown-6)] (7) were synthesized by the reaction of Ba[N(SiMe(3))(2)](2)(THF)(2) and the corresponding 1,2,4-diazaphospholes in the presence of 18-crown-6 in THF or DMSO. Complexes 1, 2, 3, 4, and 7 have been structurally characterized. Complex 4 is the first structurally characterized barium complex in which the two organic ligands are located on the same side of 18-crown-6 (cis conformation). The (31)P{(1)H} NMR spectra suggested a partial dissociation of the barium 1,2,4-diazaphospholides 2, 4, and 7 into the corresponding ion associated complexes in solutions.

  7. SALT reveals the barium central star of the planetary nebula Hen 2-39

    NASA Astrophysics Data System (ADS)

    Miszalski, B.; Boffin, H. M. J.; Jones, D.; Karakas, A. I.; Köppen, J.; Tyndall, A. A.; Mohamed, S. S.; Rodríguez-Gil, P.; Santander-García, M.

    2013-12-01

    Classical barium stars are binary systems which consist of a late-type giant enriched in carbon and slow neutron capture (s-process) elements and an evolved white dwarf (WD) that is invisible at optical wavelengths. The youngest observed barium stars are surrounded by planetary nebulae (PNe), ejected soon after the wind accretion of polluted material when the WD was in its preceding asymptotic giant branch (AGB) phase. Such systems are rare but powerful laboratories for studying AGB nucleosynthesis as we can measure the chemical abundances of both the polluted star and the nebula ejected by the polluter. Here, we present evidence for a barium star in the PN Hen 2-39 (PN G283.8-04.2) as one of only a few known systems. The polluted giant is very similar to that found in WeBo 1 (PN G135.6+01.0). It is a cool (Teff = 4250 ± 150 K) giant enhanced in carbon ([C/H] = 0.42 ± 0.02 dex) and barium ([Ba/Fe] = 1.50 ± 0.25 dex). A spectral type of C-R3 C24 nominally places Hen 2-39 amongst the peculiar early R-type carbon stars; however, the barium enhancement and likely binary status mean that it is more likely to be a barium star with similar properties, rather than a true member of this class. An AGB star model of initial mass 1.8 M⊙ and a relatively large carbon pocket size can reproduce the observed abundances well, provided mass is transferred in a highly conservative way from the AGB star to the polluted star (e.g. wind Roche lobe overflow). It also shows signs of chromospheric activity and photometric variability with a possible rotation period of ˜5.5 d likely induced by wind accretion. The nebula exhibits an apparent ring morphology in keeping with the other PNe around barium stars (WeBo 1 and A 70) and shows a high degree of ionization implying the presence of an invisible hot pre-WD companion that will require confirmation with UV observations. In contrast to A 70, the nebular chemical abundance pattern is consistent with non-Type I PNe, in keeping with the

  8. A water setting tetracalcium phosphate-dicalcium phosphate dihydrate cement.

    PubMed

    Burguera, E F; Guitián, F; Chow, L C

    2004-11-01

    The development of a calcium phosphate cement, comprising tetracalcium phosphate (TTCP) and dicalcium phosphate dihydrate (DCPD), that hardens in 14 min with water as the liquid or 6 min with a 0.25 mol/L sodium phosphate solution as the liquid, without using hydroxyapatite (HA) seeds as setting accelerator, is reported. It was postulated that reduction in porosity would increase cement strength. Thus, the effects of applied pressure during the initial stages of the cement setting reaction on cement strength and porosity were studied. The cement powder comprised an equimolar mixture of TTCP and DCPD (median particle sizes 17 and 1.7 microm, respectively). Compressive strengths (CS) of samples prepared with distilled water were 47.6 +/- 2.4 MPa, 50.7 +/- 4.2 MPa, and 52.9 +/- 4.7 MPa at applied pressures of 5 MPa, 15 MPa, and 25 MPa, respectively. When phosphate solution was used, the CS values obtained were 41.5 +/- 2.3 MPa, 37.9 +/- 1.7 MPa, and 38.1 +/- 2.3 MPa at the same pressure levels. Statistical analysis of the results showed that pressure produced an improvement in CS when water was used as liquid but not when the phosphate solution was used. Compared to previously reported TTCP-DCPD cements, the greater CS values and shorter setting times together with a simplified formulation should make the present TTCP-DCPD cement a useful material as a bone substitute for clinical applications.

  9. Calcium Phosphate Nanoparticle Adjuvant

    PubMed Central

    He, Qing; Mitchell, Alaina R.; Johnson, Stacy L.; Wagner-Bartak, Claus; Morcol, Tulin; Bell, Steve J. D.

    2000-01-01

    Vaccination to protect against human infectious diseases may be enhanced by using adjuvants that can selectively stimulate immunoregulatory responses. In a murine model, a novel nanoparticulate adjuvant composed of calcium phosphate (CAP) was compared with the commonly used aluminum (alum) adjuvants for its ability to induce immunity to herpes simplex virus type 2 (HSV-2) and Epstein-Barr virus (EBV) infections. Results indicated that CAP was more potent as an adjuvant than alum, elicited little or no inflammation at the site of administration, induced high titers of immunoglobulin G2a (IgG2a) antibody and neutralizing antibody, and facilitated a high percentage of protection against HSV-2 infection. Additional benefits of CAP include (i) an insignificant IgE response, which is an important advantage over injection of alum compounds, and (ii) the fact that CAP is a natural constituent of the human body. Thus, CAP is very well tolerated and absorbed. These studies were performed with animal models. By virtue of the potency of this CAP adjuvant and the relative absence of side effects, we believe that this new CAP formulation has great potential for use as an adjuvant in humans. PMID:11063495

  10. Piperaquine phosphate: reproduction studies.

    PubMed

    Longo, Monica; Pace, Silvia; Messina, Monica; Ferraris, Laura; Brughera, Marco; Ubben, David; Mazuè, Guy

    2012-12-01

    In embryofetal studies in rat and rabbit Piperaquine phosphate (PQP) was not teratogenic at the maximal tolerated dose, even in presence of fetal exposure. In peri- post-natal study in rat, PQP did not interfere with the course of delivery at the dose of 5 mg/kg/day (treatment Gestation Day(GD)6-Lactation Day(LD)21) as well as up to the dose of 20 mg/kg/day (treatment GD6-17 and LD1-21). PQP at the dose of 80 mg/kg, induced prolonged gestation, dystocic delivery and increase perinatal mortality both with interruption of treatment (GD6 to GD17 and LD1-21) and with continuous dosing (GD19-LD21). PQP did not interfere with lactation and pup growth and development, in presence of clear exposure during suckling period, irrespective of the dose and treatment schedules. It was not possible to identify the mechanism leading to the delivery delay. In a comparative study using other antimalarials, only Mefloquine gave similar findings to PQP. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. Barium sulfate micro- and nanoparticles as bioinert reference material in particle toxicology.

    PubMed

    Loza, Kateryna; Föhring, Isabell; Bünger, Jürgen; Westphal, Götz A; Köller, Manfred; Epple, Matthias; Sengstock, Christina

    2016-12-01

    The inhalation of particles and their exposure to the bronchi and alveoli constitute a major public health risk. Chemical as well as particle-related properties are important factors for the biological response but are difficult to separate from each other. Barium sulfate is a completely inert chemical compound, therefore it is ideally suited to separate these two factors. The biological response of rat alveolar macrophages (NR8383) was analyzed after exposure to barium sulfate particles with three different diameters (40 nm, 270 nm, and 1.3 μm, respectively) for 24 h in vitro (particle concentrations from 12.5 to 200 μg mL(-)(1)). The particles were colloidally stabilized as well as fluorescently-labeled by carboxymethylcellulose, conjugated with 6-aminofluorescein. All kinds of barium sulfate particles were efficiently taken up by NR8383 cells and found inside endo-lysosomes, but never in the cell nucleus. Neither an inflammatory nor a cytotoxic response was detected by the ability of dHL-60 and NR8383 cells to migrate towards a chemotactic gradient (conditioned media of NR8383 cells) and by the release of inflammatory mediators (CCL2, TNF-α, IL-6). The particles neither caused apoptosis (up to 200 μg mL(-)(1)) nor necrosis (up to 100 μg mL(-)(1)). As only adverse reaction, necrosis was found at a concentration of 200 μg mL(-)(1) of the largest barium sulfate particles (1.3 μm). Barium sulfate particles are ideally suited as bioinert control to study size-dependent effects such as uptake mechanisms of intracellular distributions of pure particles, especially in nanotoxicology.

  12. Recent advances in phosphate biosensors.

    PubMed

    Upadhyay, Lata Sheo Bachan; Verma, Nishant

    2015-07-01

    A number of biosensors have been developed for phosphate analysis particularly, concerning its negative impact within the environmental and biological systems. Enzymatic biosensors comprising either a single or multiple enzymatic system have been extensively used for the direct and indirect analysis of phosphate ions. Furthermore, some non-enzymatic biosensors, such as affinity-based biosensors, provide an alternative analytical approach with a higher selectivity. This article reviews the recent advances in the field of biosensor developed for phosphate estimation in clinical and environmental samples, concerning the techniques involved, and the sensitivity toward phosphate ions. The biosensors have been classified and discussed on the basis of the number of enzymes used to develop the analytical system, and a comparative analysis has been performed.

  13. Toxicological review of inorganic phosphates.

    PubMed

    Weiner, M L; Salminen, W F; Larson, P R; Barter, R A; Kranetz, J L; Simon, G S

    2001-08-01

    Inorganic phosphate salts are widely used as food ingredients and in a variety of commercial applications. The United States Food and Drug Administration (FDA) considers inorganic phosphates "Generally Recognized As Safe" (GRAS) (FDA, 1973a, 1979) [FDA: Food and Drug Administration 1973a. GRAS (Generally Recognized as Safe) food ingredients-phosphates. NTIS PB-221-224, FDA, Food and Drug Administration, 1979. Phosphates; Proposed Affirmation of and Deletion From GRAS Status as Direct and Human Food Ingredients. Federal Register 44 (244). 74845-74857, 18 December (1979)] and the European Union (EU) allows inorganic phosphates to be added directly to food (EU Directive 95/2/EC as amended by 98/72/EC). In this review, data on the acute, subchronic and chronic toxicity, genotoxicity, teratogenicity and reproductive toxicity from the published literature and from unpublished studies by the manufacturers are reviewed. Based on the toxicity data and similar chemistry, the inorganic phosphates can be separated into four major classes, consisting of monovalent salts, divalent salts, ammonium salts and aluminum salts. The proposed classification scheme supports the use of toxicity data from one compound to assess the toxicity of another compound in the same class. However, in the case of eye and skin irritation, the proposed classification scheme cannot be used because a wide range of responses exists within each class. Therefore, the eye and skin hazards associated with an individual inorganic phosphate should be assessed on a chemical-by-chemical basis. A large amount of toxicity data exists for all four classes of inorganic phosphates. The large and comprehensive database allows an accurate assessment of the toxicity of each class of inorganic phosphate. Overall, all four classes of inorganic phosphates exhibit low oral, inhalation and dermal toxicities. Based on these data, humans are unlikely to experience adverse effects when the daily phosphorus consumption remains

  14. 21 CFR 137.175 - Phosphated flour.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 2 2014-04-01 2014-04-01 false Phosphated flour. 137.175 Section 137.175 Food and... CONSUMPTION CEREAL FLOURS AND RELATED PRODUCTS Requirements for Specific Standardized Cereal Flours and Related Products § 137.175 Phosphated flour. Phosphated flour, phosphated white flour, and...

  15. 21 CFR 137.175 - Phosphated flour.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 2 2013-04-01 2013-04-01 false Phosphated flour. 137.175 Section 137.175 Food and... CONSUMPTION CEREAL FLOURS AND RELATED PRODUCTS Requirements for Specific Standardized Cereal Flours and Related Products § 137.175 Phosphated flour. Phosphated flour, phosphated white flour, and...

  16. 21 CFR 137.175 - Phosphated flour.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 2 2012-04-01 2012-04-01 false Phosphated flour. 137.175 Section 137.175 Food and... CONSUMPTION CEREAL FLOURS AND RELATED PRODUCTS Requirements for Specific Standardized Cereal Flours and Related Products § 137.175 Phosphated flour. Phosphated flour, phosphated white flour, and...

  17. Role of isovalent substitution of strontium for barium in the superconducting properties of cuprates with thallium monolayers

    SciTech Connect

    Maignan, A.; Martin, C.; Huve, M.; Michel, C.; Hervieu, M.; Raveau, B. )

    1993-04-01

    The isovalent substitution of strontium for barium in thallium monolayer cuprates is studied; three series of oxides have been isolated and characterized by X-ray diffraction: the 1201 phases TlBa[sub 1.2][sub [minus

  18. Barium adsorption on Si(100)-(2×1) at room temperature: a bi-polar scanning tunneling microscopy study

    NASA Astrophysics Data System (ADS)

    Hu, X.; Yao, X.; Peterson, C. A.; Sarid, D.; Yu, Z.; Wang, J.; Marshall, D. S.; Curless, J. A.; Ramdani, J.; Droopad, R.; Hallmark, J. A.; Ooms, W. J.

    2000-06-01

    The initial stages of barium adsorption on Si(100)-(2×1) at room temperature has been studied by ultrahigh vacuum scanning tunneling microscopy (STM) under both positive and negative sample-bias imaging conditions. Two distinct adsorption sites have been identified by the high-resolution STM images. It was found that, with the substrate held at room temperature, barium atoms can occupy both valley-bridge sites in the trough between silicon dimers and silicon-vacancy sites. It is possible to image the barium atoms at valley-bridge sites with both negative and positive sample bias, revealing filled and empty surface states, respectively. For barium atoms adsorbed at vacancy sites, however, it is only possible to obtain filled-state images, and imaging with positive sample bias will induce the removal of the atom, possibly transferred to the tip, revealing a missing silicon dimer below.

  19. First-principles study of thermodynamic stability and the electronic properties of intrinsic vacancy defects in barium hafnate.

    PubMed

    Alay-e-Abbas, S M; Shaukat, A

    2014-10-29

    The formation of intrinsic vacancy defects in barium hafnate, BaHfO3 and their corresponding electronic structures have been investigated using first-principles calculations. The thermodynamics of pristine and vacancy defects containing barium hafnate have been analyzed. Formation energies for neutral and fully charged Ba, Hf and O vacancies have been evaluated for determining their stability with respect to different chemical environments. From the calculated electronic structure and density of states, it is found that cation deficient barium hafnate is hole-doped, while the incorporation of oxygen vacancy retains the insulating nature of this material. The defect reaction energies for partial and full Schottky reactions are also computed, which controls the properties of non-stoichiometric barium hafnate.

  20. Barium Cycling During the Paleocene-Eocene Thermal Maximum: Evidence From Ba/Ca in Foraminifera

    NASA Astrophysics Data System (ADS)

    Hall, J. M.; Zachos, J. C.; Turekian, K. K.

    2004-12-01

    The Paleocene-Eocene thermal maximum (PETM) around 55 Ma reflects short-term, rapid climate change during a period of intense greenhouse climate. This interval is characterized by a negative carbon isotopic shift, interpreted as a release of methane from seafloor gas hydrate reservoirs. This perturbation of the carbon cycle is accompanied by significantly greater rates of euhedral barite accumulation in deep sea sediment commonly believed to be a reflection of elevated primary productivity in surface waters. An interpretation of higher productivity during the PETM, however, is contrary to microfossil assemblage data which indicates a decrease in primary productivity. It has also been suggested that the increase in barite accumulation during the PETM may have been the result of an increase in dissolved barium concentrations in the deep ocean coeval with methane release. This supposition has support from the fact that modern gas hydrate reservoirs are surrounded by pore waters with dissolved barium concentrations considerably higher than that of seawater. This investigation utilizes the barium content of foraminifera as a proxy to reconstruct changes in the barium concentration of the ocean. At 55 Ma, Ba/Ca decreases between 25 to 28% in the planktic foraminifer \\textit{Morozovella velascoensis}, indicating a decrease in the barium concentration of the surface ocean. These results bolster the theory that there was increased biogenic barite precipitation during the PETM. Changes in surface water temperature and pH may have altered species assemblages such that celestite (SrSO4) precipitating organisms enriched in barium as BaSO4 (possibly acantharia) were dominant, modifying the barite precipitation pathways, which affected water column barite cycling. Ba/Ca and Cd/Ca measurements on benthic foraminifera show a positive correlation with Mn/Ca, indicating contamination of manganese oxide coatings. This contamination is in part due to the greater surface to volume

  1. Effect of barium ion on p-aminohippurate transport in basolateral membrane vesicles isolated from rat kidney cortex.

    PubMed

    Hori, M; Gemba, M

    1985-06-01

    To clarify the cause of the stimulation of p-aminohippurate (PAH) accumulation in rat kidney cortical slices by barium, an experiment was carried out with basolateral membrane vesicles isolated from rat kidney cortex. The effect of barium on PAH uptake by the membrane vesicles was compared with that of verapamil which also stimulated PAH accumulation in the slices. The enzyme marker for basolateral membrane, (Na+ + K+)- ATPase, was enriched 15-fold and the brushborder enzyme marker, alkaline phosphatase, was 1.3-fold in our membrane preparation. Contamination in this preparation by lysosomes, mitochondria and cytosol was also low but that by endoplasmic reticulum was slightly high as judged by the enzyme markers. PAH uptake by the membrane vesicles possessed the usual characteristics, i.e., sodium-dependence and probenecid-sensitivity. PAH uptake by the membrane vesicles was enhanced by barium, but not by verapamil. On the other hand, barium did not affect tetraethylammonium (TEA) uptake by the vesicles, and verapamil strongly inhibited it. Manganese also stimulated PAH uptake to the same extent as did barium, but calcium and strontium did not affect the uptake. Barium did not act on sodium transport in the membrane vesicles. An 'anion-sensitively transported lipophilic cation', triphenylmethylphosphonium iodide (TPMP), uptake was depressed by barium. These results suggest that barium stimulates selectively PAH uptake in basolateral membrane vesicles. Its stimulatory action may contribute at least partly to an increase in PAH accumulation in rat kidney cortical slices by this ion and may prove useful in an analysis of the mechanism of PAH transport system in renal basolateral membranes.

  2. Thiosulfate Reduces Calcium Phosphate Nephrolithiasis

    PubMed Central

    Asplin, John R.; Donahue, Susan E.; Lindeman, Christina; Michalenka, Anne; Strutz, Kelly Laplante; Bushinsky, David A.

    2009-01-01

    An uncontrolled trial reported that sodium thiosulfate reduces formation of calcium kidney stones in humans, but this has not been established in a controlled human study or animal model. Using the genetic hypercalciuric rat, an animal model of calcium phosphate stone formation, we studied the effect of sodium thiosulfate on urine chemistries and stone formation. We fed genetic hypercalciuric rats normal food with or without sodium thiosulfate for 18 wk and measured urine chemistries, supersaturation, and the upper limit of metastability of urine. Eleven of 12 untreated rats formed stones compared with only three of 12 thiosulfate-treated rats (P < 0.002). Urine calcium and phosphorus were higher and urine citrate and volume were lower in the thiosulfate-treated rats, changes that would increase calcium phosphate supersaturation. Thiosulfate treatment lowered urine pH, which would lower calcium phosphate supersaturation. Overall, there were no statistically significant differences in calcium phosphate supersaturation or upper limit of metastability between thiosulfate-treated and control rats. In vitro, thiosulfate only minimally affected ionized calcium, suggesting a mechanism of action other than calcium chelation. In summary, sodium thiosulfate reduces calcium phosphate stone formation in the genetic hypercalciuric rat. Controlled trials testing the efficacy and safety of sodium thiosulfate for recurrent kidney stones in humans are needed. PMID:19369406

  3. Uranium endowments in phosphate rock.

    PubMed

    Ulrich, Andrea E; Schnug, Ewald; Prasser, Horst-Michael; Frossard, Emmanuel

    2014-04-15

    This study seeks to identify and specify the components that make up the prospects of U recovery from phosphate rock. A systems approach is taken. The assessment includes i) reviewing past recovery experience and lessons learned; ii) identifying factors that determine recovery; and iii) establishing a contemporary evaluation of U endowments in phosphate rock reserves, as well as the available and recoverable amounts from phosphate rock and phosphoric acid production. We find that in the past, recovery did not fulfill its potential and that the breakup of the Soviet Union worsened then-favorable recovery market conditions in the 1990s. We find that an estimated 5.7 million tU may be recoverable from phosphate rock reserves. In 2010, the recoverable tU from phosphate rock and phosphoric acid production may have been 15,000 tU and 11,000 tU, respectively. This could have filled the world U supply-demand gap for nuclear energy production. The results suggest that the U.S., Morocco, Tunisia, and Russia would be particularly well-suited to recover U, taking infrastructural considerations into account. We demonstrate future research needs, as well as sustainability orientations. We conclude that in order to promote investment and production, it seems necessary to establish long-term contracts at guaranteed prices, ensuring profitability for phosphoric acid producers. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Enhanced constitutive invasion activity in human nontumorigenic keratinocytes exposed to a low level of barium for a long time.

    PubMed

    Thang, Nguyen D; Yajima, Ichiro; Ohnuma, Shoko; Ohgami, Nobutaka; Kumasaka, Mayuko Y; Ichihara, Gaku; Kato, Masashi

    2015-02-01

    We have recently demonstrated that exposure to barium for a short time (≤4 days) and at a low level (5 µM = 687 µg/L) promotes invasion of human nontumorigenic HaCaT cells, which have characteristics similar to those of normal keratinocytes, suggesting that exposure to barium for a short time enhances malignant characteristics. Here we examined the effect of exposure to low level of barium for a long time, a condition mimicking the exposure to barium through well water, on malignant characteristics of HaCaT keratinocytes. Constitutive invasion activity, focal adhesion kinase (FAK) protein expression and activity, and matrix metalloproteinase 14 (MMP14) protein expression in primary cultured normal human epidermal keratinocytes, HaCaT keratinocytes, and HSC5 and A431 human squamous cell carcinoma cells were augmented following an increase in malignancy grade of the cells. Constitutive invasion activity, FAK phosphorylation, and MMP14 expression levels of HaCaT keratinocytes after treatment with 5 µM barium for 4 months were significantly higher than those of control untreated HaCaT keratinocytes. Taken together, our results suggest that exposure to a low level of barium for a long time enhances constitutive malignant characteristics of HaCaT keratinocytes via regulatory molecules (FAK and MMP14) for invasion.

  5. Fabrication and Characterization of Carbonized Rice Husk/Barium Titanate Nanocomposites

    NASA Astrophysics Data System (ADS)

    Melvin, G. J. H.; Wang, Z.; Ni, Q.-Q.; Siambun, N. J.; Rahman, M. M.

    2017-09-01

    Carbon materials were prepared by carbonizing rice husk (RHs) at 2500°C. Few- and multi-layer graphene were obtained from this carbonization process. Barium titanate (BTO) nanoparticles were fabricated by using sol-gel method. Then, the BTO nanoparticles were grafted onto the surface of carbonized rice husk (CRH) to fabricate CRH/BTO nanocomposites. The nanocomposites were characterized using scanning transmission electron microscopy (STEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman measurement, and X-ray photoelectron spectroscopy (XPS). Based on the broadening of (1 1 0) peak from XRD result, the average crystalline size of BTO nanoparticles were calculated to be 16.5 nm. Coexistence of cubic and tetragonal phase of BTO nanoparticles is expected, based on the XRD and Raman results. From XPS result, carbon, barium, titanium, and oxygen peaks were also observed. The combination of CRH with BTO can integrate the properties of these two components to form nanocomposites for broad applications.

  6. Gamma-ray shielding and structural properties of barium-bismuth-borosilicate glasses

    NASA Astrophysics Data System (ADS)

    Bootjomchai, Cherdsak; Laopaiboon, Jintana; Yenchai, Chadet; Laopaiboon, Raewat

    2012-07-01

    The attenuation coefficients of barium-bismuth-borosilicate glasses have been measured for gamma-ray photon energies of 662, 1173 and 1332 keV using a narrow beam transmission geometry. These coefficients were then used to obtain the values of mass attenuation coefficients, effective atomic number, effective electron density and mean free path. Good agreement has been observed between experimental and theoretical values of these parameters. From the obtained results it is reported here that from the barium-bismuth-borosilicate glasses are better shields to gamma-radiations in comparison to the standard radiation shielding concretes from the shielding point of view. The molar volume, FTIR and acoustic investigations have been used to study the structural properties of the prepared glass system. The obtained results reveal that the formation of non-bridging oxygens occurs at higher concentration of Bi2O3.

  7. Self-assembly of a tetrahedral 58-nuclear barium vanadium oxide cluster.

    PubMed

    Kastner, Katharina; Puscher, Bianka; Streb, Carsten

    2013-01-07

    We report the synthesis and characterization of a molecular barium vanadium oxide cluster featuring high nuclearity and high symmetry. The tetrameric, 2.3 nm cluster H(5)[Ba(10)(NMP)(14)(H(2)O)(8)[V(12)O(33)](4)Br] is based on a bromide-centred, octahedral barium scaffold which is capped by four previously unknown [V(12)O(33)](6-) clusters in a tetrahedral fashion. The compound represents the largest polyoxovanadate-based heterometallic cluster known to date. The cluster is formed in organic solution and it is suggested that the bulky N-methyl-2-pyrrolidone (NMP) solvent ligands allow the isolation of this giant molecule and prevent further condensation to a solid-state metal oxide. The cluster is fully characterized using single-crystal XRD, elemental analysis, ESI mass spectrometry and other spectroscopic techniques.

  8. Mechanisms of laser induced modification of lead and barium vanadate glasses

    NASA Astrophysics Data System (ADS)

    Dongol, Ruhil; Tweeton, Landon; Faris, Cory; Feller, Steve; Affatigato, Mario

    2011-01-01

    We report on our investigations on the mechanisms for structural and morphological change in lead and barium vanadate glasses modified by 785 nm laser irradiation. The fundamental process is thermal in nature, leading to phase decomposition, phase changes, and mass transport in the center of the irradiated region, as well as the formation of lead-or barium-rich debris zones. Crystallization is also a consequence of the exposure to the laser light. We further report on preirradiation experiments in which low-power exposure above a determined energy threshold results in structural changes that bridge the gap between the amorphous state and the ultimate crystalline arrangement. Finally, we discuss the application of the laser irradiation in the making of vanadate microspheres.

  9. Barium hexaferrite/graphene oxide: controlled synthesis and characterization and investigation of its magnetic properties

    NASA Astrophysics Data System (ADS)

    Maddahfar, Mahnaz; Ramezani, Majid; Mostafa Hosseinpour-Mashkani, S.

    2016-08-01

    In the present study, barium hexaferrite nanocrystals (BaFe12O19) were successfully synthesized through the two-step sol-gel method in an aqueous solution in the presence of barium nitrate and iron (III) nitrate. Besides, the effect of the molar ratio of graphene oxide on the particle size and magnetic properties of final product was investigated. In this research, glucose plays a role as capping and chelating agent in the synthesis of BaFe12O19/graphene oxide. Moreover, it was found that the size, morphology, and magnetic properties of the final products could be greatly influenced by the molar ratio of graphene oxide. BaFe12O19/graphene oxide was characterized by using X-ray diffraction, scanning electron microscope, Fourier transform infrared spectroscopy, vibrating sample magnetometer, and energy-dispersive spectrometry.

  10. Elimination of barium sulphate from acrylic bone cements. Use of two iodine-containing monomers.

    PubMed

    Artola, A; Gurruchaga, M; Vázquez, B; San Román, J; Goñi, I

    2003-10-01

    The aim of this work is to present a new approach to joint arthroplasty failure related to bone cement mantle. As barium sulphate is considered one of the main causes of mechanical weakness in the cement, we substituted this inorganic radiopacifier of the solid component for radiopaque monomers in the liquid component. We obtained two different cements, one containing 5 vol% 2-[2',3',5'-triiodobenzoyl] ethyl methacrylate (TIBMA) and the other containing 3,5-diiodine salicylic methacrylate (DISMA). In both cases, the mechanical properties of these new cements were better than those of the barium sulphate-containing cement. The radiopacity obtained was comparable to that of the aforementioned cement and all the samples showed good biocompatibility.

  11. The electric field structure of auroral arcs as determined from barium plasma injection experiments

    NASA Technical Reports Server (NTRS)

    Wescott, E. M.

    1981-01-01

    Barium plasma injection experiments have revealed a number of features of electric fields in and near auroral forms extending from a few hundred to many thousands of km in altitude. There is evidence for V-type potential structures over some auroras, but not in others. For some auroral arcs, large E fields are found at ionospheric altitudes outside the arc but the E field inside the arc is near zero. In a few other auroras, most recently one investigated in an experiment conducted from Poker Flat on March 22, 1980, large, rapidly fluctuating E fields were detected by barium plasma near 600 km altitude. These E fields suggest that the motion of auroral rays can be an effect of low-altitude electric fields, or that V-type potential structures may be found at low altitudes.

  12. The CAMEO barium release - E/parallel/ fields over the polar cap

    NASA Technical Reports Server (NTRS)

    Heppner, J. P.; Miller, M. L.; Pongratz, M. B.; Smith, G. M.; Smith, L. L.; Mende, S. B.; Nath, N. R.

    1981-01-01

    Four successive thermite barium releases at an altitude of 965 km over polar cap invariant latitudes 84 to 76 deg near magnetic midnight were conducted from the orbiting second stage of the vehicle that launched Nimbus 7; the releases were made as part of the CAMEO (Chemically Active Material Ejected in Orbit) program. This was the first opportunity to observe the behavior of conventional barium release when conducted at orbital velocity in the near-earth magnetic field. The principal unexpected characteristic in the release dynamics was the high, 1.4 to 2.6 km/s, initial Ba(+) expansion velocity relative to an expected velocity of 0.9 km/s. Attention is also given to neutral cloud expansion, initial ion cloud expansion, convective motion, and the characteristics of field-aligned motion. The possibility of measuring parallel electric fields over the polar cap by observing perturbations in the motion of the visible ions is assessed.

  13. Characterization of individual barium titanate nanorods and their assessment as building blocks of new circuit architectures.

    PubMed

    Zagar, Kristina; Hernandez-Ramirez, Francisco; Prades, Joan Daniel; Morante, Joan Ramon; Rečnik, Aleksander; Ceh, Miran

    2011-09-23

    In this work, we report on the integration of individual BaTiO(3) nanorods into simple circuit architectures. Polycrystalline BaTiO(3) nanorods were synthesized by electrophoretic deposition (EPD) of barium titanate sol into aluminium oxide (AAO) templates and subsequent annealing. Transmission electron microscopy (TEM) observations revealed the presence of slabs of hexagonal polymorphs intergrown within cubic grains, resulting from the local reducing atmosphere during the thermal treatment. Electrical measurements performed on individual BaTiO(3) nanorods revealed resistivity values between 10 and 100 Ω cm, which is in good agreement with typical values reported in the past for oxygen-deficient barium titanate films. Consequently the presence of oxygen vacancies in their structure was indirectly validated. Some of these nanorods were tested as proof-of-concept humidity sensors. They showed reproducible responses towards different moisture concentrations, demonstrating that individual BaTiO(3) nanorods may be integrated in complex circuit architectures with functional capacities.

  14. Barium permeability of neuronal nicotinic receptor alpha 7 expressed in Xenopus oocytes.

    PubMed Central

    Sands, S B; Costa, A C; Patrick, J W

    1993-01-01

    The rat alpha 7 neuronal nicotinic acetylcholine receptor was expressed and studied in Xenopus oocytes. The magnitude and reversal potential of instantaneous whole cell currents were examined in solutions containing varying concentrations of either calcium or barium, and in the presence or absence of the intracellular calcium chelator BAPTA. In external barium, application of nicotine elicits an inwardly rectifying response; in calcium the response is larger and has a linear IV relation. Pretreatment of oocytes with BAPTA-AM could not prevent activation of calcium-dependent chloride channels in external Ringer containing calcium. Using an extended GHK equation, the permeability ratio PBa/PNa of the alpha 7 receptor was determined to be about 17. Our results suggest that alpha 7 nicotinic receptors are highly permeable to divalent cations. PMID:8312496

  15. Realization of hexagonal barium ferrite thick films on Si substrates using a screen printing technique

    NASA Astrophysics Data System (ADS)

    Chen, Yajie; Smith, Ian; Geiler, Anton L.; Vittoria, Carmine; Zagorodnii, Volodymyr; Celinski, Zbigniew; Harris, Vincent G.

    2008-05-01

    Hexagonal barium ferrite thick films (50-200 µm) have been deposited on Si and Al2O3/Si substrates using a screen printing technique. X-ray diffractometry, scanning electron microscopy and magnetometry were used to characterize and correlate the ferrite films' microstructure and magnetic properties. The experiments indicated that an Al2O3 underlayer was effective in preventing silicon diffusion into the barium ferrite films during a final sintering treatment at temperatures above 1100 °C. A two-stage sintering process allowed a reasonable tradeoff between mechanical and magnetic properties. This work reveals the feasibility of fabrication of thick ferrite films on large substrates (up to 25 mm in diameter) for future planar microwave devices compatible with semiconductor integrated circuits processing.

  16. Effect of Mg-Zr substitution and microwave processing on magnetic properties of barium hexaferrite

    NASA Astrophysics Data System (ADS)

    Sharma, Manju; Kashyap, Subhash C.; Gupta, H. C.

    2014-09-01

    The effect of substitution of Mg-Zr for Fe in M-type barium hexaferrite (BHF) and of processing technique on the magnetic properties and microstructure has been reported in the present paper. Significant changes in magnetic properties have been observed on substituting Fe ions by Mg and Zr ions in M-type barium hexaferrite, i.e. BaFe12O19 as well as by single mode microwave processing. The single mode microwave processing of the undoped sample reduced the coercivity to nearly 25% of the value for the sintered sample along with the enhancement in magnetization, thereby making it suitable for memory devices. The improvement in magnetic properties is explained on the basis of microstructure. The addition of substituents, though assisted in the formation of single phase, it, however, degraded the magnetization besides decreasing the coercivity, possibly due to substitution at the octahedral sites.

  17. CORRELATED STRONTIUM AND BARIUM ISOTOPIC COMPOSITIONS OF ACID-CLEANED SINGLE MAINSTREAM SILICON CARBIDES FROM MURCHISON

    SciTech Connect

    Liu, Nan; Savina, Michael R.; Gallino, Roberto; Davis, Andrew M.; Bisterzo, Sara; Gyngard, Frank; Käppeler, Franz; Cristallo, Sergio; Dauphas, Nicolas; Pellin, Michael J.; Dillmann, Iris

    2015-04-08

    We present strontium, barium, carbon, and silicon isotopic compositions of 61 acid-cleaned presolar SiC grains from Murchison. Comparison with previous data shows that acid washing is highly effective in removing both strontium and barium contamination. For the first time, by using correlated Sr-88/Sr-86 and Ba-138/Ba-136 ratios in mainstream SiC grains, we are able to resolve the effect of C-13 concentration from that of C-13-pocket mass on s-process nucleosynthesis, which points toward the existence of large C-13 pockets with low C-13 concentrations in asymptotic giant branch stars. The presence of such large C-13 pockets with a variety of relatively low C-13 concentrations seems to require multiple mixing processes in parent asymptotic giant branch stars of mainstream SiC grains.

  18. CORRELATED STRONTIUM AND BARIUM ISOTOPIC COMPOSITIONS OF ACID-CLEANED SINGLE MAINSTREAM SILICON CARBIDES FROM MURCHISON

    SciTech Connect

    Liu, Nan; Davis, Andrew M.; Dauphas, Nicolas; Pellin, Michael J.; Savina, Michael R.; Gallino, Roberto; Bisterzo, Sara; Gyngard, Frank; Käppeler, Franz; Cristallo, Sergio; Dillmann, Iris

    2015-04-10

    We present strontium, barium, carbon, and silicon isotopic compositions of 61 acid-cleaned presolar SiC grains from Murchison. Comparison with previous data shows that acid washing is highly effective in removing both strontium and barium contamination. For the first time, by using correlated {sup 88}Sr/{sup 86}Sr and {sup 138}Ba/{sup 136}Ba ratios in mainstream SiC grains, we are able to resolve the effect of {sup 13}C concentration from that of {sup 13}C-pocket mass on s-process nucleosynthesis, which points toward the existence of large {sup 13}C pockets with low {sup 13}C concentrations in asymptotic giant branch stars. The presence of such large {sup 13}C pockets with a variety of relatively low {sup 13}C concentrations seems to require multiple mixing processes in parent asymptotic giant branch stars of mainstream SiC grains.

  19. A critical velocity interaction between fast barium and strontium atoms and the terrestial ionospheric plasma

    NASA Technical Reports Server (NTRS)

    Deehr, C. S.; Wescott, E. M.; Stenbaek-Nielsen, H.; Romick, G. J.; Hallinan, T. J.; Foeppl, H.

    1982-01-01

    A disk of barium and strontium vapor traveling radially outward, perpendicular to the geomagnetic field lines, may be created by the detonation of a high-explosive, radially shaped charge with a liner composed of the two metals in the upper atmosphere. Because of solar radiation resonance, both the barium and the strontium may be optically tracked. Observations indicate the early formation of the metal ions thus evolved into a disk-shaped, stellate structure with a dark hole at the center of a radial structure. The results of these experiments indicate that the process could occur on a cosmic scale, and that unconfirmed aspects of the theory relating to this process could be determined through variation of the parameters in future radial rocket experiments.

  20. Characterization of individual barium titanate nanorods and their assessment as building blocks of new circuit architectures

    NASA Astrophysics Data System (ADS)

    Žagar, Kristina; Hernandez-Ramirez, Francisco; Prades, Joan Daniel; Morante, Joan Ramon; Rečnik, Aleksander; Čeh, Miran

    2011-09-01

    In this work, we report on the integration of individual BaTiO3 nanorods into simple circuit architectures. Polycrystalline BaTiO3 nanorods were synthesized by electrophoretic deposition (EPD) of barium titanate sol into aluminium oxide (AAO) templates and subsequent annealing. Transmission electron microscopy (TEM) observations revealed the presence of slabs of hexagonal polymorphs intergrown within cubic grains, resulting from the local reducing atmosphere during the thermal treatment. Electrical measurements performed on individual BaTiO3 nanorods revealed resistivity values between 10 and 100 Ω cm, which is in good agreement with typical values reported in the past for oxygen-deficient barium titanate films. Consequently the presence of oxygen vacancies in their structure was indirectly validated. Some of these nanorods were tested as proof-of-concept humidity sensors. They showed reproducible responses towards different moisture concentrations, demonstrating that individual BaTiO3 nanorods may be integrated in complex circuit architectures with functional capacities.

  1. Microwave assisted synthesis and characterization of barium titanate nanoparticles for multi layered ceramic capacitor applications.

    PubMed

    Thirumalai, Sundararajan; Shanmugavel, Balasivanandha Prabu

    2011-01-01

    Barium titanate is a common ferroelectric electro-ceramic material having high dielectric constant, with photorefractive effect and piezoelectric properties. In this research work, nano-scale barium titanate powders were synthesized by microwave assisted mechano-chemical route. Suitable precursors were ball milled for 20 hours. TGA studies were performed to study the thermal stability of the powders. The powders were characterized by XRD, SEM and EDX Analysis. Microwave and Conventional heating were performed at 1000 degrees C. The overall heating schedule was reduced by 8 hours in microwave heating thereby reducing the energy and time requirement. The nano-scale, impurity-free and defect-free microstructure was clearly evident from the SEM micrograph and EDX patterns. LCR meter was used to measure the dielectric constant and dielectric loss values at various frequencies. Microwave heated powders showed superior dielectric constant value with low dielectric loss which is highly essential for the fabrication of Multi Layered Ceramic Capacitors.

  2. Surface-initiated polymerization from barium titanate nanoparticles for hybrid dielectric capacitors.

    PubMed

    Paniagua, Sergio A; Kim, Yunsang; Henry, Katherine; Kumar, Ritesh; Perry, Joseph W; Marder, Seth R

    2014-03-12

    A phosphonic acid is used as a surface initiator for the growth of polystyrene and polymethylmethacrylate (PMMA) from barium titanate (BTO) nanoparticles through atom transfer radical polymerization with activators regenerated by electron transfer. This results in the barium titanate cores embedded in the grafted polymer. The one-component system, PMMA-grafted-BTO, achieves a maximum extractable energy density of 2 J/cm(3) at a field strength of ∼220 V/μm, which exhibits a 2-fold increase compared to that of the composite without covalent attachment or the neat polymer. Such materials have potential applications in hybrid capacitors due to the high permittivity of the nanoparticles and the high breakdown strength, mechanical flexibility, and ease of processability due to the organic polymer. The synthesis, processing, characterization, and testing of the materials in capacitors are discussed.

  3. Neck evaluation with barium-enhanced radiographs and CT scans after supraglottic subtotal laryngectomy.

    PubMed

    Niemeyer, J H; Balfe, D M; Hayden, R E

    1987-02-01

    Supraglottic subtotal laryngectomy (SSL) is a radical, yet voice-conserving, surgical procedure commonly performed for carcinoma of the supraglottic larynx. The pharyngograms and computed tomographic (CT) scans of 35 patients obtained after SSL were evaluated retrospectively. These examinations reliably demonstrated the changes in anatomy caused by removal of the epiglottis, aryepiglottic folds, and false vocal cords. Fourteen patients had documented recurrence of cancer; five mucosal, nine extramucosal. Three of five macroscopic mucosal recurrences in the larynx/pharynx were detected on the barium pharyngograms; the two mucosal lesions not seen were in the base of the tongue and tonsillar fossa. CT enabled detection of five of five recurrences and was superior to pharyngography in demonstrating the soft-tissue extent of disease. CT findings mimicking recurrence were seen in two patients: one with diffuse histiocytic lymphoma; the second, with benign hyperkeratosis. Barium and CT examinations are useful adjuncts to the clinical examination in detecting recurrent squamous cell carcinoma in patients following SSL.

  4. Analysis of the magnetic properties nanoscale barium hexaferrite (BHF) prepared by milling and ultrasonic method

    NASA Astrophysics Data System (ADS)

    Novizal; Edie, Sasito; Manawan, Mykel. T. E.

    2016-11-01

    Barium hexaferrite (BHF) is well established material which widely used respectively as permanent magnets. In this research, we report our recent investigation on magnetic properties analysis of barium hexaferrite (BHF) compounds with a ratio of Fe/Ba: 11 prepared by a mechanical alloying process and high power ultrasonic destruction to promote the soft magnetic properties. The investigation carried out by Scanning Electron Microscope (SEM) shows the grain size between 500-1500 nm, it indicates that each grain is composed of several crystallites or polycrystalline. By mean of X-ray diff raction revealed the phase composition and the mean crystallite size <70 nm. The Characterization of the magnetic properties of the effects of downsizing the particle size of ∼ 200 nm to ∼ 50 nm by the ultasonik method provide saturation value of 0.35 T, remanent 0.24 T and the coercivity is 115 kA / m.

  5. Detergent phosphate bans and eutrophication

    SciTech Connect

    Lee, G.F.; Jones, R.A.

    1986-04-01

    The Vollenweider-OECD eutrophication model has been expanded to approximately 400 lakes. It is possible to make a quantitative prediction of the effects of a detergent phosphate ban and thereby to ascertain the potential benefits of such a ban. In order to assess the effect of a detergent phosphate ban on water quality it is necessary to know the percentage of phosphorus in the domestic waste water that enters the water body, either directly or indirectly, and the percentage of the total phosphorus load that is derived from domestic wastewater. Although detergent phosphate bans generally will not result in an overall improvement to water quality, there may be some situations in which eutrophication-related water quality would be improved by a ban. 8 references, 1 figure, 1 table.

  6. Effect of chloride incorporation on the crystallization of zirconium-barium-lanthanum-aluminum fluoride glass

    NASA Technical Reports Server (NTRS)

    Neilson, G. F.; Smith, G. L.; Weinberg, M. C.

    1985-01-01

    One aspect of the influence of preparation procedure on the crystallization behavior of a zirconium-barium-lanthanum-aluminum fluoride glass was studied. The crystallization pattern of this glass may be affected by the chlorine concentration within it. In particular, when such glasses are heated at low temperatures, the alpha-Ba-Zr-F6 crystalline phase forms only in those glasses which contain chloride.

  7. Dielectric and structural study of polymer composites based on polyethylene and barium titanate

    NASA Astrophysics Data System (ADS)

    Castro, R. A.; Kononov, A. A.; Dao, T. H.; Dolginsev, D. M.

    2017-07-01

    Structural and dielectric properties of polymeric composites on the basis of polyethylene and a titanate of barium are investigated. It is shown that the studied system can be considered as the composite including electrically isolated spherical particles of filler in a polymeric matrix. Emergence of a maximum of dielectric permeability and loss factor is connected with strengthening of interaction between polar groups of a polymeric matrix and the polarized particles of ferroelectric ceramic BaTiO3.

  8. High-frequency magnetic properties and attenuation characteristics for barium ferrite composites

    NASA Astrophysics Data System (ADS)

    Li, Z. W.; Lin, G. Q.; Wu, Y. P.; Kong, L. B.

    2009-04-01

    High-frequency magnetic properties and attenuation characteristics for barium-ferrite/epoxy composites have been studied. The methods for increasing μ' and μ″ and controlling fR, including ion substitution, doping of small amount of oxides, effect of damping, as well as the modification of particle sizes and shapes, are introduced. The results show that the composites are potential candidates for use as electromagnetic (EM) attenuation materials with low reflectivity and broad bandwidth at 2-18 GHz.

  9. Neutron beam test of barium fluoride crystal for dark matter direct detection

    NASA Astrophysics Data System (ADS)

    Guo, C.; Ma, X. H.; Wang, Z. M.; Bao, J.; Dai, C. J.; Guan, M. Y.; Liu, J. C.; Li, Z. H.; Ren, J.; Ruan, X. C.; Yang, C. G.; Yu, Z. Y.; Zhong, W. L.

    2016-10-01

    In order to test the capabilities of Barium Fluoride (BaF2) crystal for dark matter direct detection, nuclear recoils are studied with mono-energetic neutron beam. The energy spectra of nuclear recoils, quenching factors for elastic scattering neutrons and discrimination capability between neutron inelastic scattering events and γ events are obtained for various recoil energies of the F content in BaF2.

  10. Modification of gray iron produced by induction melting with barium strontium

    NASA Astrophysics Data System (ADS)

    Modzelevskaya, G.; Feoktistov, A. V.; Selyanin, I. F.; Kutsenko, A. I.; Kutsenko, A. A.

    2016-09-01

    The article provides analysis of results of gray iron experimental melts in induction furnace and the following melt modification with barium-strontium carbonate (BSC-2). It is shown that modification positively affects mechanical and casting properties and as-cast iron structure. It was established that BSC-2 granulated immediately prior to use has greater impact on melt than BSC-2 of the same faction, supplied by the manufacturer.

  11. The effect of cathode geometry on barium transport in hollow cathode plasmas

    SciTech Connect

    Polk, James E. Mikellides, Ioannis G.; Katz, Ira; Capece, Angela M.

    2014-05-14

    The effect of barium transport on the operation of dispenser hollow cathodes was investigated in numerical modeling of a cathode with two different orifice sizes. Despite large differences in cathode emitter temperature, emitted electron current density, internal xenon neutral and plasma densities, and size of the plasma-surface interaction region, the barium transport in the two geometries is qualitatively very similar. Barium is produced in the insert and flows to the surface through the porous structure. A buildup of neutral Ba pressure in the plasma over the emitter surface can suppress the reactions supplying the Ba, restricting the net production rate. Neutral Ba flows into the dense Xe plasma and has a high probability of being ionized at the periphery of this zone. The steady state neutral Ba density distribution is determined by a balance between pressure gradient forces and the drag force associated with collisions between neutral Ba and neutral Xe atoms. A small fraction of the neutral Ba is lost upstream. The majority of the neutral Ba is ionized in the high temperature Xe plasma and is pushed back to the emitter surface by the electric field. The steady state Ba{sup +} ion density distribution results from a balance between electrostatic and pressure forces, neutral Xe drag and Xe{sup +} ion drag with the dominant forces dependent on location in the discharge. These results indicate that hollow cathodes are very effective at recycling Ba within the discharge and therefore maintain a high coverage of Ba on the emitter surface, which reduces the work function and sustains high electron emission current densities at moderate temperatures. Barium recycling is more effective in the cathode with the smaller orifice because the Ba is ionized in the dense Xe plasma concentrated just upstream of the orifice and pushed back into the hollow cathode. Despite a lower emitter temperature, the large orifice cathode has a higher Ba loss rate through the orifice

  12. Nanoparticles for cultural heritage conservation: calcium and barium hydroxide nanoparticles for wall painting consolidation.

    PubMed

    Giorgi, Rodorico; Ambrosi, Moira; Toccafondi, Nicola; Baglioni, Piero

    2010-08-16

    Nanotechnology provides new concepts and materials for the consolidation and protection of wall paintings. In particular, humble calcium and barium hydroxide nanoparticles offer a versatile and highly efficient tool to combat the main degradation processes altering wall paintings. Clear example of the efficacy and potentiality of nanotechnology is represented by the conservation in situ of Maya wall paintings in the archaeological area in Calakmul (Mexico).

  13. Effect of chloride incorporation on the crystallization of zirconium-barium-lanthanum-aluminum fluoride glass

    NASA Technical Reports Server (NTRS)

    Neilson, G. F.; Smith, G. L.; Weinberg, M. C.

    1985-01-01

    One aspect of the influence of preparation procedure on the crystallization behavior of a zirconium-barium-lanthanum-aluminum fluoride glass was studied. The crystallization pattern of this glass may be affected by the chlorine concentration within it. In particular, when such glasses are heated at low temperatures, the alpha-Ba-Zr-F6 crystalline phase forms only in those glasses which contain chloride.

  14. Preliminary experiments on phase conjugation for flow visualization. [barium titanate single crystals

    NASA Technical Reports Server (NTRS)

    Weimer, D.; Howes, W. L.

    1984-01-01

    Barium titanate single crystals are discussed in the context of: the procedure for polarizing a crystal; a test for phase conjugation; transients in the production of phase conjugation; real time readout by a separate laser of a hologram induced within the crystal, including conjugation response times to on-off switching of each beam; and a demonstration of a Twyman-Green interferometer utilizing phase conjugation.

  15. Establishment of a protocol for determining gastrointestinal transit time in mice using barium and radiopaque markers.

    PubMed

    Myagmarjalbuu, Bolormaa; Moon, Myeong Ju; Heo, Suk Hee; Jeong, Seo In; Park, Jong-Seong; Jun, Jae Yeoul; Jeong, Yong Yeon; Kang, Heoung Keun

    2013-01-01

    The purpose of this study was to establish a minimally invasive and reproducible protocol for estimating the gastrointestinal (GI) transit time in mice using barium and radiopaque markers. Twenty 5- to 6-week-old Balb/C female mice weighing 19-21 g were used. The animals were divided into three groups: two groups that received loperamide and a control group. The control group (n = 10) animals were administered physiological saline (1.5 mL/kg) orally. The loperamide group I (n = 10) and group II (n = 10) animals were administered 5 mg/kg and 10 mg/kg loperamide orally, respectively. Thirty minutes after receiving the saline or loperamide, the mice was administered 80 µL of barium solution and six iron balls (0.5 mm) via the mouth and the upper esophagus by gavage, respectively. Afterwards, the mice were continuously monitored with fluoroscopic imaging in order to evaluate the swallowing of the barium solution and markers. Serial fluoroscopic images were obtained at 5- or 10-min intervals until all markers had been excreted from the anal canal. For analysis, the GI transit times were subdivided into intestinal transit times (ITTs) and colon transit times (CTTs). The mean ITT was significantly longer in the loperamide groups than in the control group (p < 0.05). The mean ITT in loperamide group II (174.5 ± 32.3) was significantly longer than in loperamide group I (133.2 ± 24.2 minute) (p < 0.05). The mean CTT was significantly longer in loperamide group II than in the control group (p < 0.05). Also, no animal succumbed to death after the experimental procedure. The protocol for our study using radiopaque markers and barium is reproducible and minimally invasive in determining the GI transit time of the mouse model.

  16. Establishment of a Protocol for Determining Gastrointestinal Transit Time in Mice Using Barium and Radiopaque Markers

    PubMed Central

    Myagmarjalbuu, Bolormaa; Moon, Myeong Ju; Heo, Suk Hee; Jeong, Seo In; Park, Jong-Seong; Jun, Jae Yeoul; Kang, Heoung Keun

    2013-01-01

    Objective The purpose of this study was to establish a minimally invasive and reproducible protocol for estimating the gastrointestinal (GI) transit time in mice using barium and radiopaque markers. Materials and Methods Twenty 5- to 6-week-old Balb/C female mice weighing 19-21 g were used. The animals were divided into three groups: two groups that received loperamide and a control group. The control group (n = 10) animals were administered physiological saline (1.5 mL/kg) orally. The loperamide group I (n = 10) and group II (n = 10) animals were administered 5 mg/kg and 10 mg/kg loperamide orally, respectively. Thirty minutes after receiving the saline or loperamide, the mice was administered 80 µL of barium solution and six iron balls (0.5 mm) via the mouth and the upper esophagus by gavage, respectively. Afterwards, the mice were continuously monitored with fluoroscopic imaging in order to evaluate the swallowing of the barium solution and markers. Serial fluoroscopic images were obtained at 5- or 10-min intervals until all markers had been excreted from the anal canal. For analysis, the GI transit times were subdivided into intestinal transit times (ITTs) and colon transit times (CTTs). Results The mean ITT was significantly longer in the loperamide groups than in the control group (p < 0.05). The mean ITT in loperamide group II (174.5 ± 32.3) was significantly longer than in loperamide group I (133.2 ± 24.2 minute) (p < 0.05). The mean CTT was significantly longer in loperamide group II than in the control group (p < 0.05). Also, no animal succumbed to death after the experimental procedure. Conclusion The protocol for our study using radiopaque markers and barium is reproducible and minimally invasive in determining the GI transit time of the mouse model. PMID:23323030

  17. Phase conjugation, isotropic and anisotropic higher order diffraction generation, and image correlation using photorefractive barium titanate

    NASA Astrophysics Data System (ADS)

    Buranasiri, Prathan

    2005-04-01

    Using barium titanate as the photorefractive material, we demonstrate phase conjugation, beam coupling, higher diffraction order generation. At small incident angles less than 0.015 radian, both codirectional isotropic self-diffraction (CODIS) and contradirectional isotropic self-diffraction (CONDIS) are generated simultaneously. At bigger incident angles approximately more than 0.2094 radian, only codirectional anisotropic-self diffraction (CODAS) are generated. On going imaging correlation is also showing.

  18. Phosphate-Bonded Fly Ash.

    DTIC Science & Technology

    1994-12-09

    FCODE OC ______________ ARLINGTON VA 22217-5660 - dis~bu~i.19~ 3 B Navy Case No. 75,787 PATENTS PHOSPHATE -BONDED FLY ASH IN’NA G. TALMY DEBORAH A. HAUGHT...2 3 , CaO. MgO, etc. with which the H.PO4 reacts to form the polymer-like phosphate bonds which hold the fly ash particles together. In the second...conventional means. The moisture (water) content of the aqueous HP0 4 /fly ash mixture is preferably from about 3 to about 5 weight percent for semidry

  19. Single molecule fluorescence imaging as a technique for barium tagging in neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Jones, B. J. P.; McDonald, A. D.; Nygren, D. R.

    2016-12-01

    Background rejection is key to success for future neutrinoless double beta decay experiments. To achieve sensitivity to effective Majorana lifetimes of ~ 1028 years, backgrounds must be controlled to better than 0.1 count per ton per year, beyond the reach of any present technology. In this paper we propose a new method to identify the birth of the barium daughter ion in the neutrinoless double beta decay of 136Xe. The method adapts Single Molecule Fluorescent Imaging, a technique from biochemistry research with demonstrated single ion sensitivity. We explore possible SMFI dyes suitable for the problem of barium ion detection in high pressure xenon gas, and develop a fiber-coupled sensing system with which we can detect the presence of bulk Ba++ ions remotely. We show that our sensor produces signal-to-background ratios as high as 85 in response to Ba++ ions when operated in aqueous solution. We then describe the next stage of this R&D program, which will be to demonstrate chelation and fluorescence in xenon gas. If a successful barium ion tag can be developed using SMFI adapted for high pressure xenon gas detectors, the first essentially zero background, ton-scale neutrinoless double beta decay technology could be realized.

  20. Accidental embryo irradiation during barium enema examinations: An estimation of absorbed dose

    SciTech Connect

    Damilakis, J.; Perisinakis, K.; Grammatikakis, J.

    1996-04-01

    The purpose of this report is to investigate the possibility of an embryo to receive a dose of more than 10 cGy, the threshold of malformation induction in embryos reported by the International Commission on Radiological Protection, during barium enema examinations. Thermoluminescent dosimeters were place in a phantom to calculate the depth-to-skin conversion coefficient needed for dose estimation at the average embryo depth in patients. Barium enema examinations were performed in 20 women of childbearing age with diagnostic problems demanding longer fluoroscopy times. Doses at 6 cm, the average embryo depth, were determined by measurements at the patients` skin followed by dose calculation at the site of interest. The range of doses estimated at embryo depth for patients was 1.9 to 8.2 cGy. The dose always exceeded 5 cGy when fluoroscopy time was longer than 7 minutes. The dose at the embryo depth never exceeded 10 cGy. This study indicates that fluoroscopy time should not exceed 7 minutes in childbearing-age female patients undergoing barium enema examinations. 6 refs., 1 fig., 2 tabs.

  1. Computer modelling of the reduction of rare earth dopants in barium aluminate

    SciTech Connect

    Rezende, Marcos V. dos S; Valerio, Mario E.G.; Jackson, Robert A.

    2011-08-15

    Long lasting phosphorescence in barium aluminates can be achieved by doping with rare earth ions in divalent charge states. The rare earth ions are initially in a trivalent charge state, but are reduced to a divalent charge state before being doped into the material. In this paper, the reduction of trivalent rare earth ions in the BaAl{sub 2}O{sub 4} lattice is studied by computer simulation, with the energetics of the whole reduction and doping process being modelled by two methods, one based on single ion doping and one which allows dopant concentrations to be taken into account. A range of different reduction schemes are considered and the most energetically favourable schemes identified. - Graphical abstract: The doping and subsequent reduction of a rare earth ion into the barium aluminate lattice. Highlights: > The doping of barium aluminate with rare earth ions reduced in a range of atmospheres has been modelled. > The overall solution energy for the doping process for each ion in each reducing atmosphere is calculated using two methods. > The lowest energy reduction process is predicted and compared with experimental results.

  2. Patient experiences of colonoscopy, barium enema and CT colonography: a qualitative study.

    PubMed

    Von Wagner, C; Knight, K; Halligan, S; Atkin, W; Lilford, R; Morton, D; Wardle, J

    2009-01-01

    Previous studies of patient experience with bowel screening tests, in particular CT colonography (CTC), have superimposed global rating scales and not explored individual experience in detail. To redress this, we performed qualitative interviews in order to characterize patient expectations and experiences in depth. Following ethical permission, 16 patients undergoing CTC, 18 undergoing colonoscopy and 15 undergoing barium enema agreed to a semi-structured interview by a health psychologist. Interviews were recorded, responses transcribed and themes extracted with the aim of assimilating individual experiences to facilitate subsequent development and interpretation of quantitative surveys of overall satisfaction with each diagnostic test. Transcript analysis identified three principal themes: physical sensations, social interactions and information provision. Physical sensations differed for each test but were surprisingly well tolerated overall. Social interactions with staff were perceived as very important in colouring the whole experience, particularly in controlling the feelings of embarrassment, which was critical for all procedures. Information provision was also an important determinant of experience. Verbal feedback was most common during colonoscopy and invariably reassuring. However, patients undergoing CTC received little visual or verbal feedback and were often confused regarding the test outcome. Barium enema had no specific advantage over other tests. Qualitative interviews provided important perspectives on patient experience. Our data demonstrated that models describing the quality of medical encounters are applicable to single diagnostic episodes. Staff interactions and information provision were particularly important. We found advantages specific to both CTC and colonoscopy but none for barium enema. CTC could benefit greatly from improved information provision following examination.

  3. Precipitation of Calcium, Magnesium, Strontium and Barium in Tissues of Four Acacia Species (Leguminosae: Mimosoideae)

    PubMed Central

    He, Honghua; Bleby, Timothy M.; Veneklaas, Erik J.; Lambers, Hans; Kuo, John

    2012-01-01

    Precipitation of calcium in plants is common. There are abundant studies on the uptake and content of magnesium, strontium and barium, which have similar chemical properties to calcium, in comparison with those of calcium in plants, but studies on co-precipitation of these elements with calcium in plants are rare. In this study, we compared morphologies, distributional patterns, and elemental compositions of crystals in tissues of four Acacia species grown in the field as well as in the glasshouse. A comparison was also made of field-grown plants and glasshouse-grown plants, and of phyllodes of different ages for each species. Crystals of various morphologies and distributional patterns were observed in the four Acacia species studied. Magnesium, strontium and barium were precipitated together with calcium, mainly in phyllodes of the four Acacia species, and sometimes in branchlets and primary roots. These elements were most likely precipitated in forms of oxalate and sulfate in various tissues, including epidermis, mesophyll, parenchyma, sclerenchyma (fibre cells), pith, pith ray and cortex. In most cases, precipitation of calcium, magnesium, strontium and barium was biologically induced, and elements precipitated differed between soil types, plant species, and tissues within an individual plant; the precipitation was also related to tissue age. Formation of crystals containing these elements might play a role in regulating and detoxifying these elements in plants, and protecting the plants against herbivory. PMID:22848528

  4. BARIUM SURFACE ABUNDANCES OF BLUE STRAGGLERS IN THE OPEN CLUSTER NGC 6819

    SciTech Connect

    Milliman, Katelyn E.; Mathieu, Robert D.; Schuler, Simon C.

    2015-09-15

    We present a barium surface abundance of 12 blue stragglers (BSs) and 18 main-sequence (MS) stars in the intermediate-age open cluster NGC 6819 (2.5 Gyr) based on spectra obtained from the Hydra Multi-object Spectrograph on the WIYN 3.5 m telescope. For the MS stars we find [Fe/H] = +0.05 ± 0.04 and [Ba/Fe] = −0.01 ± 0.10. The majority of the BS stars are consistent with these values. We identify five BSs with significant barium enhancement. These stars most likely formed through mass transfer from an asymptotic giant branch star that polluted the surface of the BS with the nucleosynthesis products generated during thermal pulsations. This conclusion aligns with the results from the substantial work done on the BSs in old open cluster NGC 188 that identifies mass transfer as the dominant mechanism for BS formation in that open cluster. However, four of the BSs with enhanced barium show no radial-velocity evidence for a companion. The one star that is in a binary is a double-lined system, meaning the companion is not a white dwarf and not the remnant of a prior AGB star. In this paper we attempt to develop a consistent scenario to explain the origin of these five BSs.

  5. Quantitative measurements of vaporization, burst ionization, and emission characteristics of shaped charge barium releases

    NASA Technical Reports Server (NTRS)

    Hoch, Edward L.; Hallinan, Thomas J.; Stenbaek-Nielsen, Hans C.

    1994-01-01

    Intensity-calibrated color video recordings of three barium-shaped charge injections in the ionopshere were used to determine the initial ionization, the column density corresponding to unity optical depth, and the yield of vaporized barium in the fast jet. It was found that the initial ionization at the burst was less than 1% and that 0% burst ionization was consistent with the observations. Owing to the Doppler shift, the column density for optical thickness in the neutral barium varies somewhat according to the velocity distribution. For the cases examined here, the column density was 2-5 x 10(exp 10) atoms/sq cm. This value, which occurred 12 to 15 s after release, should be approximately valid for most shaped charge experiments. The yield was near 30% (15% in the fast jet) for two of the releases and was somewhat lower in the third, which also had a lower peak velocity. This study also demonstrated the applicability of the computer simulation code developed for chemical releases by Stenbaek-Nielsen and provided experimental verification of the Doppler-corrected emission rates calculated b Stenbaek-Nielsen (1989).

  6. Comparison of the barium test meal and the gamma camera scanning technic in measuring gastric emptying

    SciTech Connect

    Perkel, M.S.; Fajman, W.A.; Hersh, T.

    1981-09-01

    In 21 patients with nonresected stomachs and symptoms of delayed gastric emptying, obstruction was excluded by upper gastrointestinal series and upper endoscopy; all had abnormal results of barium test meal (BTM) study. Each had repeat BTM after the administration of 10 mg of metoclopramide. Each patient also had two gamma camera studies after a technetium Tc 99m sulfur colloid labeled meal; normal saline or metoclopramide was administered before each test in a blinded and random manner. Half-time (T 1/2) and percentage of isotope remaining at six hours (GC6) were recorded. Ten asymptomatic controls had a gamma camera scanning study, and seven of these had a BTM. Nine of 19 patients had a T 1/2 in the normal range, and in 12 of 19 patients the GC6 was in the normal range. The magnitude of retention of barium at six hours on the BTM did not correlate with the T 1/2 (r = 0.076) or the GC6 (r = 0.296). Thus, these tests were not comparable in this study. By regression analysis, a significant reduction was shown in the amount of retained food and barium (P < .01), the T 1/2 (P < .01), and the GC6 (P < .01) after intramuscular administration of metoclopramide, indicating that both tests were able to evaluate the effects of this drug.

  7. Comparison of the barium test meal and the gamma camera scanning technic in measuring gastric emptying

    SciTech Connect

    Perkel, M.S.; Fajman, W.A.; Hersh, T.; Moore, C.; Davidson, E.D.; Haun, C.

    1981-09-01

    In 21 patients with nonresected stomachs and symptoms of delayed gastric emptying, obstruction was excluded by upper gastrointestinal series and upper endoscopy; all had abnormal results of barium test meal (BTM) study. Each had repeat BTM after the administration of 10 mg of metoclopramide. Each patient also had two gamma camera studies after a technetium Tc 99m sulfur colloid labeled meal; normal saline or metoclopramide was administered before each test in a blinded and random manner. Half-time (T1/2) and percentage of isotope remaining at six hours (GC6) were recorded. Ten asymptomatic controls had a gamma camera scanning study, and seven of these had a BTM. Nine of 19 patients had a T1/2 in the normal range, and in 12 of 19 patients the GC6 was in the normal range. The magnitude of retention of barium at six hours on the BTM did not correlate with the T1/2 (r . 0.076) or the GC6 (r. 0.296). Thus, these tests were not comparable in this study. By regression analysis, a significant reduction was shown in the amount of retained food and barium (P less than .01), the T1/2 (P less than .01), and the GC6 (P less than .01) after intramuscular administration of metoclopramide, indicating that both tests were able to evaluate the effects of this drug.

  8. Properties of strontium doped barium titanate powder prepared by solid state reaction

    NASA Astrophysics Data System (ADS)

    Jamaluddin, A.; Suwarni; Supriyanto, A.; Iriani, Y.

    2016-11-01

    Strontium doping material has been successfully doped to produce Barium Strontium Titanate (Ba1-xSrxTiO3) with variation in the percentage of moles of strontium 1%, 2%, 3%, 4% and 5% that processed by the solid state reaction method. Firstly, Ingredients (Barium carbonate, strontium carbonate and titanium oxide) have been mixed, milled during 6 hours to form solid powders. Then, sample pellets were pressed by mold machine which have been sintered in a furnace at 1100 °C during 2 hours. The properties of sample were observed using X-Ray Diffraction (XRD) for analyzing crystalline structure, Scanning Electron Microscopy (SEM) for showing morphological properties, RCL meter for dielectric constant. The XRD results indicated that the diffraction pattern is Ba1-xSrxTiO3 (BST) pattern. In addition, the results of General Structure Analysis System (GSAS) refinement with the Rietveld method showed that strontium doping has entered into Barium Titanate (BaTiO3). Increasing the number of moles of strontium has changed the lattice parameter and tertagonality of crystal BST. It affected the grain size and dielectric constant of BST too.

  9. Nanosized barium hexaferrite in novolac phenolic resin as microwave absorber for X-band application

    NASA Astrophysics Data System (ADS)

    Ozah, S.; Bhattacharyya, N. S.

    2013-09-01

    Nanosized barium ferrite (BaFe12O19) with Novolac phenolic resin (NPR) is developed as a magnetic absorber for application in the frequency range 8.2-12.4 GHz. The absorption is studied by modifying the microstructural properties of the ferrite inclusion with annealing temperature and its content in the composite. Transmission electron microscopy and X-ray diffraction pattern confirms the formation of hexagonal structure of barium ferrite. The crystallite size of the barium ferrite particles is in nano-range and increases with annealing temperature. The BaFe12O19/NPR composite is prepared with different weight percentage of ferrite inclusions. The complex permittivity and complex permeability is measured at X-band and found to increase with annealing temperature and contents of ferrite inclusion. Theoretical study of reflection loss gives that 2 mm absorber samples are showing the best results for X-band application. Reflection loss measurement of the samples shows absorption peak of -24.61 dB at 10.26 GHz for 30 wt%, -28.39 dB at 9.98 GHz for 40 wt% and -37.06 dB at 9.5 GHz for 50 wt% of BaFe12O19 in NPR matrix.

  10. Low-Temperature Cofired Co/Zr-Cosubstituted M-Type Barium Ferrite

    NASA Astrophysics Data System (ADS)

    Qiu, Tianhui; Li, Jie; Gan, Gongwen; Yu, Ximeng; Zhang, Huaiwu; Liu, Yingli; Jing, Yulan

    2017-02-01

    We report a study of low-temperature cofired Co/Zr-cosubstituted M-type barium ferrite, Ba(CoZr) x Fe12-2 x O19, with the objective of adjusting the saturation magnetization and coercivity to meet different application requirements. After low-temperature cofiring at 920°C, all the ferrite materials, with x = 0.00 to 1.00, exhibited single-phase M-type barium ferrite structure. Bi2O3-H3BO3-SiO2-ZnO (BBSZ) glass additive was effective in lowering the sintering temperature. Co/Zr substitution endowed barium ferrite with a wide range of saturation magnetization ( M s) and coercivity ( H c) values. M s first increased from 56.4 A m2/kg ( x = 0.0) to 57.7 A m2/kg ( x = 0.4), then decreased to 46.3 A m2/kg ( x = 1.0). H c decreased from 3931 Oe to 380 Oe as x was increased from 0.0 to 1.0. As the amount of Co/Zr substitution was increased, the magnetic permeability ( μ) increased from about 7 ( x = 0.0) to 9.5 ( x = 0.8), then decreased to about 9 ( x = 1.0).

  11. [Determination of trace barium in soil and sediment by Zeeman graphite AAS with coated graphite tube].

    PubMed

    Ji, Hai-Bing; Liu, Jin-Song; Pang, Xiao-Lu

    2007-11-01

    The sample was decomposed by HNO3-HF-HClO4. Using a tungsten-coated graphite tube, trace barium in soil and sediment was determined by Zeeman graphite AAS. To avoid producing carbide, the graphite tube was coated with tungsten. Tungsten and carbon in the surface layer of graphite tube became tungsten carbide. Tungsten carbide prevented barium and carbon from forming barium carbide, which in turn not only led to a long service life for the tube, but also increased greatly the sensitivity and precision of the determination Ba. Tungsten carbide belongs to internal filled type and can give reduction environment. To some extent, the common interfering elements co-existing in the soil and sediment had little chance to form oxides to interfere the determination of Ba in the atomization period. The method was easy and sensitive. The detection limit of Ba was 4.2 x 10(-10) g x g(-1). The relative standard deviation (RSD) was in the range of 2.0%-6.5% (n = 4). The relative deviations from the certificated values of standard soils were under 5%.

  12. Prediction of the physical properties of barium titanates using an artificial neural network

    NASA Astrophysics Data System (ADS)

    Al-Jabar, Ahmed Jaafar Abed; Al-dujaili, Mohammed Assi Ahmed; Al-hydary, Imad Ali Disher

    2017-04-01

    Barium titanate is one of the most important ceramics amongst those that are widely used in the electronic industry because of their dielectric properties. These properties are related to the physical properties of the material, namely, the density and the porosity. Thus, the prediction of these properties is highly desirable. The aim of the current work is to develop models that can predict the density, porosity, firing shrinkage, and the green density of barium titanate BaTiO3. An artificial neural network was used to fulfill this aim. The modified pechini method was used to prepare barium titanate powders with five different particle size distributions. Eighty samples were prepared using different processing parameters including the pressing rate, pressing pressure, heating rate, sintering temperature, and soaking time. In the artificial neural network (ANN) model, the experimental data set consisted of these 80 samples, 70 samples were used for training the network and 10 samples were employed for testing. A comparison was made between the experimental and the predicted data. Good performance of the ANN model was achieved, in which the results showed that the mean error for the density, porosity, shrinkage, and green density are 0.02, 0.06, 0.04, and 0.002, respectively.

  13. Radium-226 and barium as tracers of water masses in the North Atlantic (GA01-GEOTRACES)

    NASA Astrophysics Data System (ADS)

    Le Roy, Emilie; Sanial, Virginie; Charette, Matthew; Henderson, Paul; Jacquet, Stéphanie; García-Ibáñez, Maribel; Pérez, Fiz; Lherminer, Pascale; Souhaut, Marc; Jeandel, Catherine; Lacan, François; van Beek, Pieter

    2017-04-01

    In this study, we report concentrations of radium-226 (226Ra, t1/2=1602 y) and barium determined along the GEOVIDE section conducted in the North Atlantic (May-July 2014; Portugal-Greenland-Canda) in the framework of the international GEOTRACES program. A high vertical resolution (up to 22 depths per station) was achieved by analyzing small volumes (˜10 L) of seawater for 226Ra using a radon emanation technique. We will present the distribution of 226Ra activities and barium concentrations in contrasting biogeochemical regions of the North Atlantic (Iberian margin, West European Basin, Reykjanes Ridge, Irminger Sea, Greenland margin and Labrador Sea). These regions strongly differ in terms of boundary inputs, biogeochemistry and deep water formation. We observe a linear correlation between 226Ra and barium along the GEOVIDE section, which results from the dominantly conservative behavior of the two tracers. However, deviations from the linear correlation between 226Ra and Ba are found in several places. The potential causes for such deviations are investigated. Optimum multi-parameter (OMP) analysis was thus used to distinguish the relative importance of physical transport (i.e., water mass mixing) from non-conservative processes (sedimentary, river or hydrothermal inputs; uptake by particles) on the 226Ra and Ba distribution in the North Atlantic.

  14. [Discussion on barium sulfate turbidity as arbitration inspection method for sulfate in drinking water].

    PubMed

    Wei, Bin; Wang, Qin; He, Yi; Wang, Yang; Wang, Min; Liu, Yueyue

    2013-09-01

    To evaluate the suitability of barium sulfate turbidity in Standard examination methods for drinking water (GB/T 5750.5-2006) as arbitration inspection method of sulfate in drinking water by evaluation of uncertainty. The expanded uncertainty of determination result for the unknown water sample was given by evaluating all uncertainty components in process of determination of barium sulfate turbidity. The determination result of the unknown water sample is 250 mg/L , with the expanded uncertainty of 42 mg/L (kappa = 2). This method could not accurately determine the amount of sulfate which is close to health standard limited in drinking water, at the same time, it' s unsuitable as arbitration inspection method of sulfate in drinking water. Because the expanded uncertainty of determination results of the unknown water sample by barium sulfate turbidity is so big, with the confidence regions of sulfate of 208-292 mg/L. So, evaluating uncertainty of the determination results is helpful to choose the suitable arbitration inspection method.

  15. Femtosecond laser enhanced current in a thermionic diode with barium vapor

    NASA Astrophysics Data System (ADS)

    Makdisi, Y.; Kokaj, J.; Afrousheh, K.; Mathew, J.; Nair, R.; Pichler, G.

    2014-11-01

    We studied the signal from a thermionic diode when a femtosecond laser beam was spatially overlapped by an excimer pumped dye laser beam. The nanosecond dye laser was scanned from 435 to 438 nm in order to excite the autoionizing levels of barium by two photon absorption. The broadband ultrashort laser light was centered at 427 nm, which is also above the first ionization limit of barium. The bias voltage between the cell body and the tungsten rod (set at either 9 or 0 V) was used to collect electrons after the barium ions had been created by multiphoton (auto) ionization. The overall background of the thermionic signal was appreciably elevated due to the two photon ionization by the broadband femtosecond laser. We measured the thermionic signal with and without femtosecond laser overlap, and with a biasless and biased thermionic diode. The effect of the femtosecond laser was appreciable enhancement of the background ionization continuum. This was especially visible in the presence of noble gases at pressure of 50 mbar. Argon produced the largest and helium produced the smallest enhancement in the background continuum. In addition, we observed a few broad spectral features of a presumably collision induced nature.

  16. Bioavailability of barium to plants and invertebrates in soils contaminated by barite.

    PubMed

    Lamb, Dane T; Matanitobua, Vitukawalu P; Palanisami, Thavamani; Megharaj, Mallavarapu; Naidu, Ravi

    2013-05-07

    Barium (Ba) is a nonessential element to terrestrial organisms and is known to be toxic at elevated concentrations. In this study, the bioavailability and toxicity of Ba in barite (BaSO4) contaminated soils was studied using standard test organisms (Lactuca sativa L. "Great Lakes", Eisenia fetida). Contamination resulted from barite mining activities. Barium concentrations in contaminated soils determined by X-ray fluorescence were in the range 0.13-29.2%. Barite contaminated soils were shown to negatively impact both E. fetida and L. sativa relative to control soil. For E. fetida, pore-water concentrations and acid extractable Ba were linearly related to % body weight loss. In L. sativa, pore-water Ba and exchangeable Ba were both strongly related to shoot Ba and shoot biomass production. A negative linear relationship was observed between shoot Ba content and shoot weight (P < 0.0004, R(2) = 0.39), indicating that Ba accumulation is likely to have induced phytotoxicity. Plant weights were correlated to % weight loss in earthworm (r = -0.568, P = 0.028). Barium concentrations in pore-water were lower than predicted from barite solubility estimates but strongly related to exchangeable Ba, indicating an influence of ion exchange on Ba solubility and toxicity to E. fetida and L. sativa.

  17. ARE THERE ANY STARS LACKING NEUTRON-CAPTURE ELEMENTS? EVIDENCE FROM STRONTIUM AND BARIUM

    SciTech Connect

    Roederer, Ian U.

    2013-01-01

    The cosmic dispersion in the abundances of the heavy elements strontium and barium in halo stars is well known. Strontium and barium are detected in most cool, metal-poor giants, but are these elements always detectable? To identify stars that could be considered probable candidates for lacking these elements, I examine the stellar abundance data available in the literature for 1148 field stars and 226 stars in dwarf galaxies, 776 of which have metallicities lower than [Fe/H] <-2.0. Strontium or barium have been detected in all field, globular cluster, and dwarf galaxy environments studied. All upper limits are consistent with the lowest detected ratios of [Sr/H] and [Ba/H]. The frequent appearance of these elements raises the intriguing prospect that at least one kind of neutron-capture reaction operates as often as the nucleosynthesis mechanisms that produce lighter elements, such as magnesium, calcium, or iron, although the yields of heavy elements may be more variable.

  18. Estimation of effective dose and radiation risk in pediatric barium studies procedures.

    PubMed

    Sulieman, A; Elhag, B; Alkhorayef, M; Babikir, E; Theodorou, K; Kappas, C; Bradley, D

    2017-07-21

    The objectives of this study are to assess pediatric radiation exposure in certain barium studies and to quantify the organ and effective doses and radiation risk resultant from patients' irradiation. A total of 69 pediatric barium studies for upper and lower gastrointestinal tract. Patients' radiation dose was quantified in terms of Entrance surface air kerma (ESAKs) using exposure parameters and DosCal software. Organ and effective doses (E) were extrapolated using national Radiological Protection Board software (NRPB-R279). The mean ± (SD) and the range of patient doses per procedure were 3.7 ± 0.4 (1.0-13.0)mGy, 7.4 ± 1.7(5.5-8.0)mGy and 1.4 ± 0.9 (0.5-3.6)mGy for barium meal, swallow and enema, respectively. The mean effective doses were 0.3 ± 0.03 (0.08-1.1)mSv, 0.2 ± 1.6 (0.44-0.7)mSv and 0.3 ± 0.9 (0.1-0.8)mSv at the same order. The radiation dose were higher compared to previous studies. Therefore, pediatrics are exposed to avoidable radiation exposure. Certain optimization measures are recommended along with establishing national diagnostic reference level (DRL) to reduce the radiation risk. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Physiologic Studies of the Pulmonary Capillary Bed after Barium Sulfate Embolization*

    PubMed Central

    Daly, Walter J.; Waldhausen, John A.

    1967-01-01

    22 anesthetized dogs were given a barium sulfate suspension intravenously in a dose sufficient to double mean pulmonary artery pressure. 10 sec breath-holding carbon monoxide diffusing capacity (DLCO10) was measured before and after this standard embolization in each dog. No post-embolic decrease in DLCO10 was observed. In the study of this apparent paradox, it was found that the potential for further increase in DLCO10 during exercise remained after embolization. During rest prolongation of breath holding to 60 sec decreased CO absorption significantly more in the embolized than in the nonembolized dogs. While DLCO10 was not affected by standard barium embolization, oxygen diffusing capacity was clearly decreased. The bronchial collateral circulation did not participate in preventing a DLCO10 decrease after embolization since surgical interruption of the bronchial circulation did not alter the response to barium. Microscopic examination of lung sections taken after standard embolization showed plugging of precapillary vessels in the 40-50 μ range. These studies suggest that acute precapillary embolic obstruction of vessels of this size interferes remarkably little with CO absorption over short periods of time, probably because of continued CO absorption in portions of the capillary net distal to the sites of impaction. The remarkable anastomotic nature of this capillary network with multiple sources of access possibly provides the anatomic basis for this observation. This study demonstrates a clear dissociation between acute changes in pulmonary vascular resistance and DLCO10—both during rest and exercise. Images PMID:6061739

  20. Stimulation of the insulin secretory mechanism following barium accumulation in pancreatic beta-cells.

    PubMed

    Berggren, P O; Andersson, B; Hellman, B

    1982-06-08

    Electrothermal atomic absorption spectroscopy was employed for measuring barium in beta-cell-rich pancreatic islets microdissected from ob/ob-mice. Both the uptake and efflux of barium displayed two distinct phases. There was a 4-fold accumulation of barium into intracellular stores when its extracellular concentration was 0.26 mM. Unlike divalent cations with more extensive intracellular accumulation, the washout of Ba2+ was not inhibited by D-glucose. Ba2+ served as a substitute for Ca2+ both in maintaining the glucose metabolism after removal of extracellular Ca2+ and making it possible for glucose to stimulate insulin release. Furthermore, Ba2+ elicited insulin release in the absence of glucose and other secretagogues. The latter effect was reversible and was markedly potentiated under conditions known to increase the beta-cell content of cyclic AMP. It is likely that the observed actions of Ba2+ are mediated by Ca2+, since Ca2+ -dependent regulatory proteins, such as calmodulin, apparently cannot bind Ba2+ specifically.