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1

Barium Sulfate  

MedlinePLUS

... uses a computer to put together x-ray images to create cross-sectional or three dimensional pictures of the inside of the body). Barium sulfate is in a class of medications called radiopaque contrast media. It works by coating the esophagus, stomach, or ...

2

The effect of calcium cations on the precipitation of barium sulfate 2: calcium ions in the presence of organic additives  

NASA Astrophysics Data System (ADS)

Calcium ions have been implicated in changing the precipitation of barium sulfate when organic additives are present, although whether it inhibits or promotes nucleation and/or growth has been disputed in the literature. We conducted a thorough investigation into the effect of calcium when additives are present and show that calcium cations do indeed promote nucleation of barium sulfate particles when compared to the appropriate control. This result is independent of the analytical method (conductivity or turbidity) used to assess precipitation. The nucleation promotion produces no change in the crystal morphology, thus morphology is not always a good indicator of nucleation or growth behavior. The extent of nucleation promotion depends on the functional group of the additive.

Jones, F.; Oliviera, A.; Parkinson, G. M.; Rohl, A. L.; Stanley, A.; Upson, T.

2004-10-01

3

Effects of nitrate and water on the oxygen isotopic analysis of barium sulfate precipitated from solution  

USGS Publications Warehouse

BaSO4 precipitated from mixed salt solutions by common techniques for SO isotopic analysis may contain quantities of H2O and NOthat introduce errors in O isotope measurements. Experiments with synthetic solutions indicate that ?18O values of CO produced by decomposition of precipitated BaSO4 in a carbon reactor may be either too low or too high, depending on the relative concentrations of SO and NO and the ?18O values of the H2O, NO, and SO. Typical ?18O errors are of the order of 0.5 to 1‰ in many sample types, and can be larger in samples containing atmospheric NO, which can cause similar errors in ?17O and ?17O. These errors can be reduced by (1) ion chromatographic separation of SO from NO, (2) increasing the salinity of the solutions before precipitating BaSO4 to minimize incorporation of H2O, (3) heating BaSO4 under vacuum to remove H2O, (4) preparing isotopic reference materials as aqueous samples to mimic the conditions of the samples, and (5) adjusting measured ?18O values based on amounts and isotopic compositions of coexisting H2O and NO. These procedures are demonstrated for SO isotopic reference materials, synthetic solutions with isotopically known reagents, atmospheric deposition from Shenandoah National Park, Virginia, USA, and sulfate salt deposits from the Atacama Desert, Chile, and Mojave Desert, California, USA. These results have implications for the calibration and use of O isotope data in studies of SOsources and reaction mechanisms.

Janet E Hannon;Johnkarl F Bohlke;Stanley J Mroczkowski

2008-01-01

4

Barium isotope fractionation in the global barium cycle: Evidence from barium minerals and precipitation experiments  

NASA Astrophysics Data System (ADS)

In this study, we present first results from an ongoing investigation on the stable barium (Ba) isotope fractionation in the natural barium cycle. Stable Ba isotope signatures of international IAEA reference materials (synthetic barium sulfate and barium carbonate), and terrestrial Ba gangue minerals have been analyzed as a first approach to evaluate potential discriminating processes in the global geochemical barium cycle. Measurements were carried out on a multi-collector ICP-MS applying a 130Ba/135Ba double spike. Data are given as per mil deviations from a laboratory Ba nitrate standard solution in the d137/134Ba notation (external 2s stdev < 0.1 per mil). Whereas the various synthetic solid standards and p.a. quality synthetic barium chloride show very similar isotope results close to the nitrate standard solution, the terrestrial barium gangue minerals (four barites, one norsethite [BaMg(CO3)2]) were depleted in the heavy isotope (d137/134Ba values between 0 and -0.2 per mil). A natural barite, from an unknown Chinese locality, gave an isotope value of -0.4 per mil. Also measured high 34S/32S and 18O/16O ratios in this sample indicate that this barite has been formed under influence of microbial sulfate reduction, probably in a marine diagenetic environment. The observed natural discriminations are by far larger than the analytical uncertainty of the isotope measurements, indicating isotope discrimination in the natural barium cycle. Precipitation experiments from aqueous barium chloride solutions at temperatures of 20° and 80°C indicate that the light Ba isotope is enriched in pure barium carbonate or barium sulfate compared to the aqueous solution. A maximum isotope fractionation of -0.3 per mil is observed, for both barium carbonate and sulfate, that seems to be influenced by precipitation rate (BaCO3) and/or the aqueous speciation, but less by temperature.

von Allmen, Katja; Böttcher, Michael E.; Samankassou, Elias; Nägler, Thomas F.

2010-05-01

5

Effects of nitrate and water on the oxygen isotopic analysis of barium sulfate precipitated from water samples.  

PubMed

BaSO(4) precipitated from mixed salt solutions by common techniques for SO(4) (2-) isotopic analysis may contain quantities of H(2)O and NO(3) (-) that introduce errors in O isotope measurements. Experiments with synthetic solutions indicate that delta(18)O values of CO produced by decomposition of precipitated BaSO(4) in a carbon reactor may be either too low or too high, depending on the relative concentrations of SO(4) (2-) and NO(3) (-) and the delta(18)O values of the H(2)O, NO(3) (-), and SO(4) (2-). Typical delta(18)O errors are of the order of 0.5 to 1 per thousand in many sample types, and can be larger in samples containing atmospheric NO(3) (-), which can cause similar errors in delta(17)O and Delta(17)O. These errors can be reduced by (1) ion chromatographic separation of SO(4) (2-) from NO(3) (-), (2) increasing the salinity of the solutions before precipitating BaSO(4) to minimize incorporation of H(2)O, (3) heating BaSO(4) under vacuum to remove H(2)O, (4) preparing isotopic reference materials as aqueous samples to mimic the conditions of the samples, and (5) adjusting measured delta(18)O values based on amounts and isotopic compositions of coexisting H(2)O and NO(3) (-). These procedures are demonstrated for SO(4) (2-) isotopic reference materials, synthetic solutions with isotopically known reagents, atmospheric deposition from Shenandoah National Park, Virginia, USA, and sulfate salt deposits from the Atacama Desert, Chile, and Mojave Desert, California, USA. These results have implications for the calibration and use of O isotope data in studies of SO(4) (2-) sources and reaction mechanisms. PMID:19021238

Hannon, Janet E; Böhlke, John Karl; Mroczkowski, Stanley J

2008-12-01

6

Effects of nitrate and water on the oxygen isotopic analysis of barium sulfate precipitated from water samples  

USGS Publications Warehouse

BaSO4 precipitated from mixed salt solutions by common techniques for SO42- isotopic analysis may contain quantities of H2O and NO3- that introduce errors in O isotope measurements. Experiments with synthetic solutions indicate that ??18O values of CO produced by decomposition of precipitated BaSO4 in a carbon reactor may be either too low or too high, depending on the relative concentrations of SO42- and NO3- and the ??18O values of the H2O, NO3-, and SO42-. Typical ??18O errors are of the order of 0.5 to 1??? in many sample types, and can be larger in samples containing atmospheric NO 3-, which can cause similar errors in ?? 17O and ??17O. These errors can be reduced by (1) ion chromatographic separation of SO42- from NO 3-, (2) increasing the salinity of the solutions before precipitating BaSO4 to minimize incorporation of H2O, (3) heating BaSO4 under vacuum to remove H2O, (4) preparing isotopic reference materials as aqueous samples to mimic the conditions of the samples, and (5) adjusting measured ??18O values based on amounts and isotopic compositions of coexisting H2O and NO 3-. These procedures are demonstrated for SO 42- isotopic reference materials, synthetic solutions with isotopically known reagents, atmospheric deposition from Shenandoah National Park, Virginia, USA, and sulfate salt deposits from the Atacama Desert, Chile, and Mojave Desert, California, USA. These results have implications for the calibration and use of O isotope data in studies of SO42- sources and reaction mechanisms.

Hannon, J. E.; Bohlke, J. K.; Mroczkowski, S. J.

2008-01-01

7

Coprecipitation of radium with barium sulfate from calcium-containing solutions  

Microsoft Academic Search

Precipitation of radium with barium sulfate from solutions obtained on treatment of thorium-containing industrial wastes has been studied by stepwise regressive analysis. The mathematical model of the process selected on an Elektronika-DZ-28 computer made it possible to prove that, unlike calcium-free solutions, coprecipitation of radium with barium sulfate from solutions highly concentrated in calcium depends on the ratio of the

A. V. Belkin; Yu. P. Kudryavskii; S. A. Anferov

1988-01-01

8

Co-precipitation of radium with barium and strontium sulfate and its impact on the fate of radium during treatment of produced water from unconventional gas extraction.  

PubMed

Radium occurs in flowback and produced waters from hydraulic fracturing for unconventional gas extraction along with high concentrations of barium and strontium and elevated salinity. Radium is often removed from this wastewater by co-precipitation with barium or other alkaline earth metals. The distribution equation for Ra in the precipitate is derived from the equilibrium of the lattice replacement reaction (inclusion) between the Ra(2+) ion and the carrier ions (e.g., Ba(2+) and Sr(2+)) in aqueous and solid phases and is often applied to describe the fate of radium in these systems. Although the theoretical distribution coefficient for Ra-SrSO4 (Kd = 237) is much larger than that for Ra-BaSO4 (Kd = 1.54), previous studies have focused on Ra-BaSO4 equilibrium. This study evaluates the equilibria and kinetics of co-precipitation reactions in Ra-Ba-SO4 and Ra-Sr-SO4 binary systems and the Ra-Ba-Sr-SO4 ternary system under varying ionic strength (IS) conditions that are representative of brines generated during unconventional gas extraction. Results show that radium removal generally follows the theoretical distribution law in binary systems and is enhanced in the Ra-Ba-SO4 system and restrained in the Ra-Sr-SO4 system by high IS. However, the experimental distribution coefficient (Kd') varies widely and cannot be accurately described by the distribution equation, which depends on IS, kinetics of carrier precipitation and does not account for radium removal by adsorption. Radium removal in the ternary system is controlled by the co-precipitation of Ra-Ba-SO4, which is attributed to the rapid BaSO4 nucleation rate and closer ionic radii of Ra(2+) with Ba(2+) than with Sr(2+). Carrier (i.e., barite) recycling during water treatment was shown to be effective in enhancing radium removal even after co-precipitation was completed. Calculations based on experimental results show that Ra levels in the precipitate generated in centralized waste treatment facilities far exceed regulatory limits for disposal in municipal sanitary landfills and require careful monitoring of allowed source term loading (ASTL) for technically enhanced naturally occurring materials (TENORM) in these landfills. Several alternatives for sustainable management of TENORM are discussed. PMID:24670034

Zhang, Tieyuan; Gregory, Kelvin; Hammack, Richard W; Vidic, Radisav D

2014-04-15

9

Precipitation of Calcium, Magnesium, Strontium and Barium in Tissues of Four Acacia Species (Leguminosae: Mimosoideae)  

PubMed Central

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

He, Honghua; Bleby, Timothy M.; Veneklaas, Erik J.; Lambers, Hans; Kuo, John

2012-01-01

10

Barium sulfate suspension as a negative oral MRI contrast agent: in vitro and human optimization studies.  

PubMed

In vitro proton spectroscopy with line-width measurements and MR imaging were performed on various concentrations of commercially available single contrast (SC), double contrast, oral and rectal barium sulfate suspensions, as well as potassium sulfate, barium chloride, barium hydroxide, and 97% pure barium sulfate suspensions. Approximately 500 ml of 20%, 40%, 60%, and 70% w/w suspensions of SC oral barium sulfate suspensions were administered to four normal volunteers, respectively, and MR images were obtained at both 1.5 T and 0.15 T. Subsequently, 500 ml of 60% w/w suspensions of SC oral barium sulfate suspensions were administered to five normal volunteers and imaged at 1.5 T. All of the inert suspensions produced line-width broadening but the SC oral barium sulfate suspension at 50% and 70% stayed in suspension even after hours of standing undisturbed. As much as 80% of the small bowel and the entire colon were well visualized using the combination of 60% or 70% w/w SC barium sulfate suspensions with SE 550/22 and FISP pulse sequences. The effect was less at 0.15 T and also with the SE 2000/45/90 pulse sequences. We conclude that barium sulfate suspensions are useful as oral MRI contrast agents. PMID:2034046

Li, K C; Tart, R P; Fitzsimmons, J R; Storm, B L; Mao, J; Rolfes, R J

1991-01-01

11

Uncertainties in the oxygen isotopic composition of barium sulfate induced by coprecipitation of nitrate.  

PubMed

Coprecipitation of nitrate and sulfate by barium has probably resulted in significant error in numerous studies dealing with the oxygen isotopic composition of natural sulfates using chemical/thermal conversion of BaSO(4) and analysis by isotope ratio mass spectrometry. In solutions where NO(3) (-)/SO(4) (2-) molar ratios are above 2 the amount of nitrate coprecipitated with BaSO(4) reaches a maximum of approximately 7% and decreases roughly linearly as the molar ratio decreases. The fraction of coprecipitated nitrate appears to increase with decreasing pH and is also affected by the nature of the cations in the precipitating solution. The size of the oxygen isotope artifact in sulfate depends both on the amount of coprecipitated nitrate and the delta(18)O and Delta(17)O values of the nitrate, both of which can be highly variable. The oxygen isotopic composition of sulfate extracted from atmospheric aerosols or rain waters are probably severely biased because photochemical nitrate is usually also present and it is highly enriched in (18)O (delta(18)O approximately 50-90 per thousand) and has a large mass-independent isotopic composition (Delta(17)O approximately 20-32 per thousand). The sulfate delta(18)O error can be 2-5 per thousand with Delta(17)O artifacts reaching as high as 4.0 per thousand. PMID:18763262

Michalski, Greg; Kasem, Michelle; Rech, Jason A; Adieu, Sabine; Showers, William S; Genna, Bernie; Thiemens, Mark

2008-10-01

12

Dielectric properties of cobalt substituted M-type barium hexaferrite prepared by co-precipitation  

Microsoft Academic Search

Barium hexaferrite was synthesised via the co-precipitation method using high purity nitrates, oxides and carbonates of iron\\u000a (III), barium (II) and ammonium hydroxide. Once a phase pure sample of barium hexaferrite was obtained, it was doped, by weight,\\u000a with 1, 2, 3, 5, 10, 15, 20 and 30% cobalt oxide (Co3O4). The addition of cobalt to the BaM had the

Philip Shepherd; Kajal K. Mallick; Roger J. Green

2007-01-01

13

Sulfate ion sensing based on a quartz-crystal microbalance immobilized with barium sulfate crystals grown on a self-assembled monolayer of phosphorylated 11-mercapto-1-undecanol  

Microsoft Academic Search

A self-assembly monolayer (SAM) of phosphorylated 11-mercapto-1-undecanol (MUD) on a quartz-crystal microbalance (QCM) gold electrode was served as an interfacial layer for subsequent adhesion of barium sulfate crystals. The subsequent process of anchoring barium sulfate crystals on the phosphorylated MUD organic film was followed using X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The atomic concentration measured by XPS

Heesoo Eun; Yoshio Umezawa

1998-01-01

14

SOURCE ASSESSMENT: MAJOR BARIUM CHEMICALS  

EPA Science Inventory

This report summarizes data on air emissions from the production of major barium chemicals. Compounds studied include barium sulfide, barium carbonate, barium chloride, barium hydroxide, and barium sulfate. In order to evaluate potential environmental effects the source severity,...

15

Barium sulphate precipitation in a pipe — an experimental study and CFD modelling  

Microsoft Academic Search

Precipitation of barium sulphate in an unpremixed feed two-dimensional tubular precipitator is studied experimentally and interpreted theoretically using a closure procedure proposed previously by the authors. The closure employs the presumed beta PDF of the inert type composition variables formed with the local values of Ba2+ and SO42? concentrations and the turbulent mixer model. The flow field is computed using

Jerzy Ba?dyga; Wojciech Orciuch

2001-01-01

16

Preparation of nanosized barium zirconate powder by thermal decomposition of urea in an aqueous solution containing barium and zirconium, and by calcination of the precipitate  

Microsoft Academic Search

The synthesis of barium zirconate was initiated by urea induced homogeneous precipitation followed by a “low temperature” thermal treatment. The kinetic of the reaction and the optimum urea\\/cation ratio have been determined by means of X-ray diffraction and Inductive Coupled Plasma analyses. It has been demonstrated that an amorphous zirconium hydrated oxide starts to precipitate followed by the precipitation of

F. Boschini; B. Robertz; A. Rulmont; R. Cloots

2003-01-01

17

Selective removal of keratan sulfate in chondroitin sulfate samples by sequential precipitation with ethanol.  

PubMed

Keratan sulfate (KS) is present as a contaminant in chondroitin sulfate (CS) mainly extracted from shark cartilage. We report a selective removal procedure of KS in CS samples by means of sequential precipitation with ethanol. Purified shark CS containing approximately 10% to 15% KS was subjected to a precipitation procedure in the presence of increasing percentages of saturated ethanol. In contrast to other solvents, 1.0 volume of ethanol was able to selectively purify CS, with a purity of approximately 100%, from KS. The current selective and simple procedure appears to be a reliable industrial preparation of CS devoid of large amounts of the residual KS. PMID:24291704

Galeotti, Fabio; Maccari, Francesca; Volpi, Nicola

2014-03-01

18

Reactions of calcium orthosilicate and barium zirconate with oxides and sulfates of various elements  

NASA Technical Reports Server (NTRS)

Calcium orthosilicate and barium zirconate were evaluated as the insulation layer of thermal barrier coatings for air cooled gas turbine components. Their reactions with various oxides and sulfates were studied at 1100 C and 1300 C for times ranging up to 400 and 200 hours, respectively. These oxides and sulfates represent potential impurities or additives in gas turbine fuels and in turbine combustion air, as well as elements of potential bond coat alloys. The phase compositions of the reaction products were determined by X-ray diffraction analysis. BaZrO3 and 2CaO-SiO2 both reacted with P2O5, V2O5, Cr2O3, Al2O3, and SiO2. In addition, 2CaO-SiO2 reacted with Na2O, BaO, MgO, and CoO and BaZrO3 reacted with Fe2O3.

Zaplatynsky, I.

1979-01-01

19

doi:10.1016/S0016-7037(03)00177-7 A thermodynamic investigation of barium and calcium sulfate stability in sediments at an  

E-print Network

doi:10.1016/S0016-7037(03)00177-7 A thermodynamic investigation of barium and calcium sulfate) Abstract--We have used a new thermodynamic model of barium and calcium sulfate solubilities- ters (Chang et al., 1996). Its occurrence is reported in altered sediments and mineral deposits forming

Paris-Sud XI, Université de

20

A new precipitation pathway for calcium sulfate dihydrate (gypsum) via amorphous and hemihydrate intermediates.  

PubMed

This work investigates the early stages of precipitation of calcium sulfate from aqueous solution at room temperature and shows for the first time that amorphous calcium sulfate (ACS) and calcium sulfate hemihydrate are sequentially precipitated prior to calcium sulfate dihydrate (gypsum). PMID:21971526

Wang, Yun-Wei; Kim, Yi-Yeoun; Christenson, Hugo K; Meldrum, Fiona C

2012-01-14

21

Aqueous hafnium sulfate chemistry: structures of crystalline precipitates.  

PubMed

Crystalline precipitates resulting from the hydrolysis and subsequent condensation of Hf(IV) aqueous acidic solutions at 60-95 °C are examined and compared. By varying the concentrations of the acid and sulfate source, a variety of complex hafnium-oxo-hydroxo-sulfate clusters are isolated and structures accessed. Four novel compounds were discovered, while the structures of two known compounds, an 18-mer and a planar hexamer, were updated. In total, the compounds described herein each contain one of four cluster architectures: 18-mer, 11-mer, nonamer, and planar hexamer. In addition, one compound contains small amounts of 19-mers together with 18-mers. As well as examining the individual structure of each complex cluster, we relate them to one another, as well as to the dense phases of HfO2, to gain an understanding of their formation and stability. Finally, the solution conditions under which each cluster forms are identified by plotting the crystallization regions of each cluster against acidity and sulfate concentration. Most clusters form under slightly acidic conditions, in decreasing size as the sulfate concentration is raised. The flat hexamer is the single exception; it appears to require more acidic solutions. The degree of hydroxo- versus oxo-bridges with changing solution conditions is assessed within the broader context of the condensates. Of specific interest is the identification of these products as they relate to the use of hydrolysis reactions in designing new materials. PMID:25299984

Kalaji, Ali; Soderholm, L

2014-10-20

22

Quantitative Analysis of Sulfate in Water by Indirect EDTA Titration  

ERIC Educational Resources Information Center

The determination of sulfate concentration in water by indirect EDTA titration is an instructive experiment that is easily implemented in an analytical chemistry laboratory course. A water sample is treated with excess barium chloride to precipitate sulfate ions as BaSO[subscript 4](s). The unprecipitated barium ions are then titrated with EDTA.…

Belle-Oudry, Deirdre

2008-01-01

23

Fabrication and surface properties of hydrophobic barium sulfate aggregates based on sodium cocoate modification  

NASA Astrophysics Data System (ADS)

Hydrophobic barium sulfate aggregates were fabricated by the direction of cocoate anions. At 30 °C, when the weight ratio of sodium cocoate to BaSO4 particles was 2.0 wt.%, the active ratio of the product reached 99.43% and the contact angle was greater than 120°. This method could not only simplify the complex modification process, but reduce energy consumption. The surface morphology, chemical structure and composition of BaSO4 aggregates were characterized by SEM, XRD, and FTIR. The results indicated that the as-synthesized BaSO4 particles were almond-liked and were composed of many interconnected nanoballs and that their surfaces were affected by cocoate anions. The adsorption of cocoate anions reversed the charge and weakened the surface polarity of BaSO4 particles, driving the formation of aggregates. And cocoate anions induced a change of the BaSO4 particles surface from hydrophilic to hydrophobic by a self-assembly and transformation process. Due to the self-assembled structure and the surface hydrophobicity, when adding the hydrophobic BaSO4 into PVC, the mechanical properties of PVC composite materials were significantly improved.

Hu, Linna; Wang, Guangxiu; Cao, Rong; Yang, Chun; Chen, Xi

2014-10-01

24

Mineral leaching, iron precipitation, and the sulfate requirement for chemolithotrophic iron oxidation  

Microsoft Academic Search

The leaching of pyrite by Thiobacillus ferrooxidans results in formation of an aqueous Fe(III) sulfato complex that leaches pyrite and precipitates excess iron sulfate. However, until recently most general texts stated that the deposits formated by bacterial leaching of pyrite consited of ferric hydroxide, implying that the massive presence of sulfate played no role in the oxidation or precipitation of

Norman Lazaroff

1997-01-01

25

Precipitation of barium flouride microcrystals from electrolytic solutions: The influence of the composition of the precipitating solutions  

NASA Astrophysics Data System (ADS)

The composition, shape and size of the particles obtained by precipitation in aqueous solutions of various barium salts (chloride, nitrate and acetate) with various fluorides (ammonium, sodium and hydrogen) have been studied by X-ray powder diffraction analysis and scanning electron microscopy. From Ba(NO 3) 2 in combination with NH 4F or NaF and from Ba(C 2H 3O 2) 2 in combination with NH 4F, NaF or HF, precipitates of pure cubic-BaF 2 (?-BaF 2) are obtained. The shape and size of ?-BaF 2 particles depend on the combination of the compounds used for the precipitation and their concentrations. It appears that only when (equal volumes of) solutions of Ba(NO 3) 2 (0.125 mol dm -3) or Ba(C 2H 3O 2) 2 (0.125 and 0.150 mol dm -3) and NH 4F (0.250 or 0.300 mol dm -3) are mixed particles are formed as more or less regular cubes with smooth faces. These crystals are suitable to be used in studies of the transport of ions from crystals to the solution and vice versa with the aid of radioactive tracers ("heterogeneous isotopic exchange" studies).

Kolar, Z.; Binsma, J. J. M.; Suboti?, B.

1984-02-01

26

Nature and spatial distribution of sulfur species in a sulfated barium-based commercial lean NOx trap catalyst  

SciTech Connect

We report observations of the nature and spatial distribution of sulfur species on a sulfated Ba-based commercial lean NO{sub x} trap (LNT) catalyst. The monolithic catalyst was sulfated in a bench flow reactor during 60/4-s NO{sub x} storage/reduction cycling to achieve a total sulfur loading of 3.4 g L{sup -1} of catalyst. Washcoat composition, structure and sulfur distribution were analyzed with electron probe microanalysis, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and temperature-programmed reduction. The most significant washcoat elements of catalytic relevance were Pt, Pd, Rh, Ba, Ce, Zr, Mg, Al, and these were present mainly in four distinct domains; Mg/Al mixed oxide with Pt, Ce; Al oxide with Rh, Pd; Ce/Zr mixed oxide with Pt, Pd, Ba (high Ba content); Ce/Zr mixed oxide with Pt, Pd, Ba (lower Ba content). Sulfur was present in the form of sulfates that decreased in concentration along the LNT axis from front to back. Barium showed the highest sulfur affinity leading to a plug-like axial progression of its sulfation. The sulfation of AI, Mg/Al, and Ce/Zr oxides was less vigorous with a more axially dispersed and less penetrating front.

Choi, Jae-Soon [ORNL; Partridge Jr, William P [ORNL; Lance, Michael J [ORNL; Walker, Larry R [ORNL; Pihl, Josh A [ORNL; Toops, Todd J [ORNL; FINNEY, Charles E A [ORNL; Daw, C Stuart [ORNL

2010-01-01

27

Precipitation method for barium metaborate (BaB2O4) synthesis from borax solution  

NASA Astrophysics Data System (ADS)

In this study, barium metaborate (BaB2O4, BMB) synthesis from the borax solution was carried out. BMB currently is used in production of ceramic glazes, luminophors, oxide cathodes as well as additives to pigments for aqueous emulsion paints and also ?-BaB2O4 single crystals are the best candidate for fabrication of solid-state UV lasers operating at a wavelength of 200 nm due to excellent nonlinear optical properties. In the present study, synthesis was carried out from the borax solution (Na2B4O7?10H2O, BDH) and barium chloride (BaCI2?2H2O, Ba) in the glass-batch reactor with stirring. The effect of, times (5-15 min), molar ratio [stoich.ration (1.0:2.0), 1.25:2.0, 1.5:2.0, 2.5:2:0, 3.0:2.0, 3.5:2.0,4.0:2.0, 5.0:2.0] and also crystallization time (2-6 hour) on the BMB yield (%) was investigated at 80 °C reaction temperature. It is found that, BMB precipitation synthesis with 90 % yield can be performed from 0.50 molar ration (BDH:Ba), under 80 °C, 15 minute, and 6 hours crystallization time. The structural properties of BMB powders were characterized by using XRD, FT-IR and DTA-TG instrumental analysis technique.

Ak?ener, Eymen; Figen, Aysel Kantürk; Pi?kin, Sabriye

2013-12-01

28

Magnetic and structural properties of M-type barium hexaferrite prepared by co-precipitation  

NASA Astrophysics Data System (ADS)

Stoichiometric and single-phase barium hexaferrite (BaM) has been synthesized by co-precipitation and an additional solid state preparative method using high-purity nitrates, oxides and carbonates of iron (III), barium (II) and ammonium hydroxide. The isochronally and isothermally measured permeability and magnetic loss tangents over 1 MHz-1 GHz in frequency remained moderately constant until a sintering temperature of 1300 °C where relative permeability of 1.3 and loss tangent of 0.06 at 1 GHz, indicate high-frequency magnetic characteristics for BaM. TGA/DTA studies showed the hexaferrite formation temperature was found to be 1050 °C. The apparent densities before and after each firing cycle showed a monotonic increase. X-ray diffraction studies established the presence of a single phase with the theoretical space group P63/mmc, and computed cell parameters of a= b=5.895 Å and c=23.199 Å. The samples exhibited a Curie point ( Tc) of 452 °C and displayed ferromagnetic resonance characteristics centred on a frequency of 500 MHz.

Shepherd, Philip; Mallick, Kajal K.; Green, Roger J.

2007-04-01

29

BARIUM BIOAVAILABILITY AS THE CHLORIDE, SULFATE, OR CARBONATE SALT IN THE RAT  

EPA Science Inventory

This study was conducted to determine how the bioavailability of a low concentration of barium (Ba) in drinking water is affected by anion speciation. Male Sprague Dawley rats weighing 250-300 grams were maintained on a diet of less than 1 mg Ba/kg of food for at least 1 month pr...

30

Structural and optical properties of Er3+/Yb3+ doped barium titanate phosphor prepared by co-precipitation method.  

PubMed

In the present work we have synthesized the Er(3+)/Yb(3+) codoped barium titanate phosphor via co-precipitation method and studied its upconversion emission properties. The prepared BaTiO3 powder was found in cubic phase as a major component and having good crystallinity revealed by the XRD analysis. Optical band gap of the cubic barium titanate was calculated using the diffuse reflectance absorption spectrum. Good green upconversion emission is observed from the samples when excited by 980 nm diode laser. The variation in upconversion emission intensity is studied with the increase in excitation power as well as temperature of the sample. It is found that the emission bands centred at 524 and 548 nm are thermally coupled and can act as a temperature sensor in the 300-480 K temperature range. PMID:24495836

Mahata, Manoj Kumar; Kumar, Kaushal; Rai, Vineet Kumar

2014-04-24

31

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

SciTech Connect

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

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

1999-10-21

32

Influence of polyethylenimine on the precipitation process of lead sulfate crystals  

Microsoft Academic Search

Crystals of lead sulfate were precipitated in a solution of polyethylenimine (PEI) using a double-jet crystallizer. PEI controlled both the nucleation rate and the growth rate, and enabled to produce fine monodispersed crystals. This effect is considered to be due to a complexation between PEI and lead ion. The on-line measurement of the variation in the lead ion concentration indicated

Akio Katayama; Takahiro Sakuma; Izumi Hirasawa

2004-01-01

33

PRIMARY SULFATE EMISSION FACTORS FOR THE NAPAP (NATIONAL ACID PRECIPITATION ASSESSMENT PROGRAM) EMISSIONS INVENTORY  

EPA Science Inventory

The report gives results of an estimation of primary sulfate emission factors for use in the 1980 and 1985 National Acid Precipitation Assessment Program (NAPAP) emissions inventories. The estimates were developed from an assessment of existing measurements data for source catego...

34

Spontaneous precipitation of calcium carbonate in the presence of chondroitin sulfate  

NASA Astrophysics Data System (ADS)

The kinetics of spontaneous precipitation of vaterite (CaCO 3) from an aqueous solution in the presence of chondroitin sulfates (CSA, CSB, CSC) was investigated by the constant composition method. The presence of chondroitin sulfate in the supersaturated solution resulted in a reduction of the crystal growth rate by 23-65%. Induction times preceding vaterite precipitation were inversely proportional to the solution's supersaturation and a surface energy of 52 mJ m -2 was calculated according to the classical nucleation theory. Chondroitin sulfate influences the particle size distribution of the vaterite crystals formed and stabilizing this mineral phase, preventing the transformation to calcite. The apparent order found from kinetics data was n>2, thus suggesting a surface nucleation mechanism.

Manoli, F.; Dalas, E.

2000-08-01

35

Calcium sulfate precipitation in the presence of water-soluble polymers.  

PubMed

The effect of four different polymers on the precipitation of calcium sulfate was investigated in the present work. The degree of inhibition was estimated from measurements of the calcium ion activity and from specific solution conductivity measurements in the supersaturated solutions during the course of the precipitation process. The effects of polyacrylic acid (PAA, three different polymers with average molecular weight 2000, 50,000, and 240,000, respectively) and of a co-polymer of PAA with polystyrene sulfonic acid (PSA, average molecular weight<20,000) were investigated with respect to their effect on the kinetics of spontaneous precipitation of calcium sulfate salts. The results of the kinetics experiments suggested that the spontaneous precipitation from supersaturated calcium sulfate solutions at 25 degrees C yielded exclusively calcium sulfate dihydrate (gypsum) both in the absence and in the presence of the polymeric additives. The induction times, preceding the formation of the solid increased in all cases in the presence of the polymeric additives. Polymer concentrations as low as 2.0 ppm increased induction time from practically zero to 10 min. The rates of precipitation were reduced according to the solutions content in the polymers added and precipitation was completely suppressed in the presence of 6.0 ppm of the polymers tested, depending on their molecular weight. The lower the molecular weight of PAA, the more efficient was the threshold inhibition and the stronger the reduction of the rates of spontaneous precipitation. PSA yielded the poorest inhibition efficiency in comparison with the PAA, possibly because of the relatively lower affinity of the sulfonate groups for the calcium ions of the surface of the solid forming. The kinetics results analysis assuming Langmuir-type adsorption of the polymeric molecules on the growing supercritical gypsum nuclei showed different affinity for the polymers tested in agreement with the respective inhibition efficiency, in the order: PAA1>PAA2>PSA>PAA3. The presence of the polymers in the supersaturated solutions resulted in modification of the precipitated gypsum crystals morphology. PMID:16920136

Lioliou, Maria G; Paraskeva, Christakis A; Koutsoukos, Petros G; Payatakes, Alkiviades C

2006-11-01

36

COMPARISON OF WET CHEMICAL AND INSTRUMENTAL METHODS FOR MEASURING AIRBORNE SULFATE  

EPA Science Inventory

Four techniques for determination of water soluble sulfate in atmospheric samples were compared including the barium sulfate turbidimetric method, the Brosset (barium-Thorin) method, the automated barium-methylthymol blue procedure and a microchemical (barium-dinitro-sulfanazo II...

37

Radiographic anatomy and barium sulfate contrast transit time of the gastrointestinal tract of bearded dragons (Pogona vitticeps).  

PubMed

The positive contrast gastrointestinal study is a common non-invasive diagnostic technique that does not require anesthesia and enables good visualization of the digestive tract. Radiographic anatomy and reference intervals for gastrointestinal contrast transit time in inland bearded dragons (Pogona vitticeps) were established using seven animals administered 15 ml/kg of a 35% w/v suspension of barium by esophageal gavage. Dorso-ventral and lateral radiographic views were performed at 0, 15, 30 min, 1, 2, 4, 6, 8, 12 h, and then every 12 h up to 96 h after barium administration. Gastric emptying was complete at a median time of 10 h (range 4-24 h). Median jejunum and small intestinal emptying times were 1 h (range 30 min-2 h) and 29 h (range 24-48 h), respectively. Median transit time for cecum was 10 h (range 8-12 h). Median time for contrast to reach the colon was 31 h (range 12-72 h) after administration. Results were compared to those obtained in other reptilian species. This technique appeared safe in fasted bearded dragons and would be clinically applicable in other lizard species. PMID:24945023

Grosset, Claire; Daniaux, Lise; Guzman, David Sanchez-Migallon; Weber, Ernest Scott; Zwingenberger, Allison; Paul-Murphy, Joanne

2014-01-01

38

Influence of semi-batch operation on the precipitation of natrojarosite particles from sulfate solutions  

NASA Astrophysics Data System (ADS)

The precipitation of natrojarosite from iron sodium sulfate solutions has been investigated at temperatures close to the atmospheric boiling point, in batch and semi-batch conditions. Semi-batch conditions make it possible to maintain a weaker iron concentration in the stirred reactor, leading to lower supersaturations, closer to those in continuous and possibly seeded MSMPRs or tanks—in series units. In these reactors, primary and secondary nucleations are few, allowing the growth of pure mono-crystalline particles of controlled size and size dispersion. Both modi operandi lead to agglomerates made of crystals of cubic habit. The surface of cauliflower-like particles from the batch modus operandi displays overlaying crystals, of size between 100 and 400 nm. The particles from the semi-batch mode, with moderate iron addition, are rougher and show bigger intergrown constitutive crystals of size up to a few microns, which denotes lesser secondary nucleation and more growth. A model is developed to characterize iron(III) and sulfate speciation with non-ideal behavior in the mother solution. It is used to compare the variations of supersaturation in the reactor between the batch and the semi-batch conditions. During the first 500 min, the supersaturation resulting from a moderate addition of iron is 10,000-10 times lower than during batch kinetics, which agrees with the reduction of secondary nucleation suggested by scanning electron micrographs. The semi-batch technique, which can be combined with the addition of support particles, is worth further work, aiming to reduce secondary nucleation and to determine the crystallite growth rate expression of natrojarosite as a function of supersaturation, using the model of solution developed in this work.

Sandré, Anne-Laure; Gaunand, Alain

2012-03-01

39

Short-term trends in sulfate deposition at selected bulk precipitation stations in New York  

USGS Publications Warehouse

Trends in rainfall-adjusted sulfate concentration were assessed for 5-yr subrecords of the 14.5-17 yr of monthly bulk-deposition data from five stations in New York by using the seasonal Kendall test. For the 5-yr subrecord from 1978 to 1982, the trends for the bulk deposition were similar to those for weekly wet-only deposition for adjacent stations of the National Atmospheric Deposition Program (NADP). The long-term trend at each of the bulk-precipitation sites was downward and statistically significant at P < 0.02, whereas 26% of the 69 subrecords had trends that were statistically significant only at P <0.2. Of these statistically significant subrecord trends, 10% were positive (opposite to the long-term trend). Furthermore, the slopes of the subrecord trends tended to be much steeper than those of the whole record. These 5-yr trends, consequently, are poor indicators of the trends that occur over much longer periods in the same record.Trends in rainfall-adjusted sulfate concentration were assessed for 5-yr subrecords of the 14. 5-17 yr of monthly bulk-deposition data from five stations in New York by using the seasonal Kendall test. For the 5-yr subrecord from 1978 to 1982, the trends for the bulk deposition were similar to those for weekly wet-only deposition for adjacent stations of the National Atmosheric Deposition Program (NADP). The long-term trend at each of the bulk-precipitation sites was downward and statistically significant at p less than 0. 02, whereas 26 percent of the 69 subrecords had trends that were statistically significant only at P less than 0. 2. Of these statistically significant subrecord trends, 10 percent were positive (opposite to the long-term trend). Furthermore, the slopes of the subrecord trends tended to be much steeper than those of the whole record. These 5-yr trends, consequently, are poor indicators of the trends that occur over much longer periods in the same record.

Hirsch, R.M.; Peters, N.E.

1988-01-01

40

Total and non-seasalt sulfate and chloride measured in bulk precipitation samples from the Kilauea Volcano area, Hawaii  

USGS Publications Warehouse

Six-month cumulative precipitation samples provide estimates of bulk deposition of sulfate and chloride for the southeast part of the Island of Hawaii during four time periods: August 1991 to February 1992, February 1992 to September 1992, March 1993 to September 1993, and September 1993 to February 1994. Total estimated bulk deposition rates for sulfate ranged from 0.12 to 24 grams per square meter per 180 days, and non-seasalt sulfate deposition ranged from 0.06 to 24 grams per square meter per 180 days. Patterns of non-seasalt sulfate deposition were generally related to prevailing wind directions and the proximity of the collection site to large sources of sulfur gases, namely Kilauea Volcano's summit and East Rift Zone eruption. Total chloride deposition from bulk precipitation samples ranged from 0.01 to 17 grams per square meter per 180 days. Chloride appeared to be predominantly from oceanic sources, as non- seasalt chloride deposition was near zero for most sites.

Scholl, M.A.; Ingebritsen, S.E.

1995-01-01

41

Low density barium and bentonite mixture versus high density barium: A comparative study to optimize negative gastrointestinal contrast agents for MRI  

Microsoft Academic Search

The purpose of this study was to compare the patient tolerance and efficacy, as magnetic resonance imaging negative oral contrast agents, of a mixture of clay compound bentonite and low density barium sulfate suspension with that of higher density barium sulfate. Twenty patients were randomized into two groups: 10 patients receiving a mixture of low concentration 60% wv barium sulfate

Mark R. Paley; Ana I. Nicolas; Patricia J. Mergo; Gladys M. Torres; Sharon S. Burton; Pablo R. Ros

1997-01-01

42

Biologically-induced precipitation of sphalerite-wurtzite nanoparticles by sulfate-reducing bacteria: implications for acid mine drainage treatment.  

PubMed

Several experiments were conducted to evaluate zinc-tolerance of sulfate-reducing bacteria (SRB) obtained from three environmental samples, two inocula from sulfide-mining districts and another inoculum from a wastewater treatment plant. The populations of SRB resisted zinc concentrations of 260 mg/L for 42 days in a sulfate-rich medium. During the experiments, sulfate was reduced to sulfide and concentrations in solution decreased. Zinc concentrations also decreased from 260 mg/L to values below detection limit. Both decreases were consistent with the precipitation of newly-formed sphalerite and wurtzite, two polymorphs of ZnS, forming <2.5-?m-diameter spherical aggregates identified by microscopy and synchrotron-?-XRD. Sulfate and zinc are present in high concentrations in acid mine drainage (AMD) even after passive treatments based on limestone dissolution. The implementation of a SRB-based zinc removal step in these systems could completely reduce the mobility of all metals, which would improve the quality of stream sediments, water and soils in AMD-affected landscapes. PMID:22414495

Castillo, Julio; Pérez-López, Rafael; Caraballo, Manuel A; Nieto, José M; Martins, Mónica; Costa, M Clara; Olías, Manuel; Cerón, Juan C; Tucoulou, Rémi

2012-04-15

43

A Mathematical Process Model for Cadmium Precipitation by Sulfate-Reducing Bacterial Biofilms  

Microsoft Academic Search

Sulfate-reducing bacterial (SRB) biofilms were grown in a flowcell in which the biofilm was grown on a fixed area of support which was supplied with recirculating medium of defined composition, volume and circulation rate. Utilization rates for substrates, production rates for products and material mass-balances for substrates and Cd were determined and a mathematical model constructed based on theoretical considerations

Christopher White; John S. Dennis; Geoffrey M. Gadd

2003-01-01

44

Stable sulfur isotopes of sulfate in precipitation and stream solutions in a northern hardwood watershed  

Microsoft Academic Search

Stable S isotopes of SO4(2-) in precipitation, throughfall, and stream water solutions in a northern hardwood watershed (Bear Brook Watershed, Maine) were examined to determine sources of stream SO4(2-) and to identify watershed processes that may affect atmospherically deposited SO4(2-) prior to reaching the streams. Similarity among temporal pattern in Delta(34)S of precipitation, throughfall, stream SO4(2-) (range: +3.4 to 9.4%),

A. C. Stam; M. J. Mitchell; H. R. Krouse; J. S. Kahl

1992-01-01

45

Structure and reactivity of zinc sulfide precipitates formed in the presence of sulfate-reducing bacteria  

Microsoft Academic Search

The biologically mediated formation of metal sulfide precipitates in anoxic sediments represents a potentially important mechanism for the sequestration of toxic metals. Current knowledge of the structure and reactivity of these biogenic metal sulfides is scarce, limiting the ability to effectively assess contaminant sequestration in, and remobilization from, these solids. In this study, SO4-reducing bacteria (Desulfovibrio sp.) were grown for

Edward Peltier; Pavan Ilipilla; David Fowle

2011-01-01

46

Preparative Separation of Proteins Using Centrifugal Precipitation Chromatography Based on Solubility in Ammonium Sulfate Solution  

Microsoft Academic Search

A preparative modification of the centrifugal precipitation chromatography (CPC) is described. The sample?loading capacity is improved in the present system by the use of convoluted tubing containing dialysis tubing instead of a dialysis membrane placed between a pair of disks equipped with mirror?imaged spiral grooves as in the original design. The system uses, basically, the same principle of as the

Henry Yu; Yoichiro Ito

2004-01-01

47

Anthropogenic sulfate aerosol and the southward shift of tropical precipitation in the late 20th century  

NASA Astrophysics Data System (ADS)

In this paper, we demonstrate a global scale southward shift of the tropical rain belt during the latter half of the 20th century in observations and global climate models (GCMs). In rain gauge data, the southward shift maximizes in the 1980s and is associated with signals in Africa, Asia, and South America. A southward shift exists at a similar time in nearly all CMIP3 and CMIP5 historical simulations, and occurs on both land and ocean, although in most models the shifts are significantly less than in observations. Utilizing a theoretical framework based on atmospheric energetics, we perform an attribution of the zonal mean southward shift of precipitation across a large suite of CMIP3 and CMIP5 GCMs. Our results suggest that anthropogenic aerosol cooling of the Northern Hemisphere is the primary cause of the consistent southward shift across GCMs, although other processes affecting the atmospheric energy budget also contribute to the model-to-model spread.

Hwang, Yen-Ting; Frierson, Dargan M. W.; Kang, Sarah M.

2013-06-01

48

Analysis of ambient, precipitation-weighted, and lake sulfate concentrations in the Adirondack region of New York.  

PubMed

AbstractIt is well known that many ecosystems in the eastern United States, including the Adirondack Mountain region of New York, are particularly sensitive to acidic deposition because the soils and lakes in the region tend to have low values of base saturation and acid neutralizing capacity, respectively [e.g. Environ Sci Policy, 1 (1998), 185]. To facilitate tracking the impacts of anthropogenic emissions on air quality, acidic deposition, and surface water quality, the National Atmospheric Deposition Program, New York State Department of Environmental Conservation, and Adirondack Lake Survey Corporation have been monitoring ambient sulfur dioxide and aerosol sulfate levels, and anion and cation concentrations in wet deposition and lake water over the past few decades. In this paper, we discuss the seasonality and year-to-year variability, and illustrate some of the complexities in estimating temporal trends in these data. The periods of analysis extended through 2000, beginning in 1991 for the ambient air quality data, 1978 for the wet deposition data, and 1982 for the lake water quality data. While the lake water SO4(2-) concentrations appear to be decreasing gradually, the air concentration data appear to have changed abruptly in the 1990s and the precipitation-weighted concentrations exhibited both gradual and sharp decreases during the same period. PMID:12667761

Civerolo, Kevin; Brankov, Elvira; Rao, S Trivikrama; Roy, Karen; Lewis, Preston; Galvin, Philip

2003-01-01

49

Precipitation  

NSDL National Science Digital Library

The representation describes precipitation. It includes a diagram of mountains, ocean, clouds and rain with an accompanying short explanation. Within the explanation the words rain, snow, hail, sleet and freezing rain are links to another screen with information and a photograph. The resource also includes a description of extremes (desert as compared with rainforest) and geographic variability of precipitation).

50

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

PubMed

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. PMID:23485244

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

2013-01-01

51

Prevention and control of sulfate scaling in the Namorado field, Campos Basin, Brazil  

SciTech Connect

Precipitation inhibitor squeeze treatments have been performed in the last 5 years in the Namorado field to avoid barium sulfate and strontium sulfate scaling in the producing tubing. This paper describes the laboratory tests conducted to select inhibitor and to simulate the squeeze operation in porous media. Based on these tests a polyacrylic acid product was used in the squeeze operations. The squeeze operation design is described as well as the strategy for analytical monitoring of the produced waters to select the wells with high precipitation potential for the prevention treatment. This paper describes the occurrence of spherical precipitated material (with morphology similar to ooids formed in natural environments) at the bottom of the well NA-C. The analysis of the ooids, associated with the production parameters, allowed the determination of the effectiveness of the squeeze treatment and the understanding of the precipitation mechanisms.

Bezerra, M.C.M.; Rosario, F.F. do; Khalil, C.N.; Milanez, P.V.A.; Souza, R.S. de [Cidade Univ., Rio de Janeiro (Brazil). Petrobras Research and Development Center

1996-08-01

52

Bacterial sulfate reduction and salinity: two controls on dolomite precipitation in Lagoa Vermelha and Brejo do Espinho (Brazil)  

Microsoft Academic Search

The hydrological system of Lagoa Vermelha, a dolomite-precipitating lagoon in Brazil, was investigated using hydrogen and oxygen stable isotopic composition of the water collected during an annual cycle (1996–1997). These data demonstrated that dolomite formed in May–June during high saline conditions. High salinity apparently provides the ions and saturation state necessary for dolomite precipitation. Ion concentrations in the lagoon water

Y. van Lith; C. Vasconcelos; R. Warthmann; J. C. F. Martins; J. A. McKenzie

2002-01-01

53

The effects of pH regulation upon the release of sulfate from ferric precipitates formed in acid mine drainage  

Microsoft Academic Search

`Batch experiments' (25:1 v:w) were used to test the effects of pH upon the release of SO?24 from ferric precipitates formed in acid mine drainage (AMD) in southeastern Kentucky. Analytical grade CaO [`quicklime'], Ca(OH)2 [hydrated lime] and CaCO3 [referred to as `limestone'] were used as alkalinity generating agents and were mixed with ferric precipitates composed of amorphous iron oxyhydroxides, jarosite

Seth Rose; W. Crawford Elliott

2000-01-01

54

Production of a Pseudomonas lipase in n-alkane substrate and its isolation using an improved ammonium sulfate precipitation technique.  

PubMed

Among the various lipidic and non-lipidic substances, normal alkanes within the chain lengths of C-12 to C-20 served as the best carbon substrates for the production of extracellular lipase by Pseudomonas species G6. Maximum lipase production of 25 U/ml of the culture broth was obtained by using n-hexadecane as the sole carbon substrate. The optimum pH of 8 and temperature of 34 + 1 degrees C were demonstrated for the production of lipase in n-hexadecane substrate. The optimum concentration of iron, which played a critical role on the lipase production, was found to be 0.25 mg/l. Lipase production could be enhanced to nearly 2.4-fold by using tributyrin at a concentration of 0.05% (v/v) in the culture medium. High recovery of the lipase protein (83%) from the culture broth was achieved by treating the culture supernatant with Silicone 21 Defoamer followed by ammonium sulfate (60% saturation) fractionation. PMID:12118695

Kanwar, Lambit; Gogoi, Binod Kumar; Goswami, Pranab

2002-09-01

55

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

USGS Publications Warehouse

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.

Szabo, B. J.; Joensuu, O.

1967-01-01

56

Precipitation and Characterization of Arsenate Phases from Calcium-Copper-Iron-Arsenic Oxide-Sulfate Hydrothermal Systems  

NASA Astrophysics Data System (ADS)

The scope of this thesis is the study of three Fe(III)-As(V) hydrothermal systems. The first one is the Fe(III)-AsO4-SO 4 system and crystalline phases that are produced under high temperature (150-225°C); this was studied to clear up previous contradicting information on this system in relation to industrial arsenic products that are formed during the autoclave processing of arsenical sulphide gold feedstocks and asses their arsenic stability. The second system studied was Cu(II)-Fe(III)-AsO 4-SO4 system at 150°C; this was investigated due to its relevance to industrial pressure leaching of copper concentrates. This system was studied in order to examine the possible effect of copper on the precipitation of scorodite. Finally, the structural and molecular examination of two members of the Ca(II)-Fe(III)-AsO4 system, namely yukonite (synthetic and natural and arseniosiderite was undertaken due to their relatively unknown nature and the potential role play in controlling arsenic release in tailings.

Gomez, Mario Alberto

57

Microbial sulfate reduction within the Iheya North subseafloor hydrothermal system constrained by quadruple sulfur isotopes  

NASA Astrophysics Data System (ADS)

Subseafloor hydrothermal system may host active and abundant microbial community. Sulfate reduction may be one of the dominant microbial metabolisms among the subseafloor ecosystem. In order to demonstrate and quantify the potential sulfate reducing activity, we analyzed sulfur isotopes (32S/33S/34S/36S) of pore water sulfate extracted from core samples at the Iheya North hydrothermal system in the Okinawa drilled by CHIKYU, 2009 (IODP Leg 331). After drilling, core samples were divided into several sections. Then, pore water was extracted on board, and stored with cadmium chloride for fixing hydrogen sulfide. In our laboratory, the samples were first divided into sulfide precipitate and supernatant liquid by centrifugation. Then, dissolved sulfate was precipitated as BaSO4 by addition of barium chloride into the supernatant liquid. After weighing, the barium sulfate was converted into silver sulfide and subsequently sulfur hexafluoride, which was purified by GC and then introduced into mass spectrometer (MAT253) through newly developed microvolume inlet for precisely determining quadruple sulfur isotopic composition. Based on pore water chemistry and temperature profile, the subseafloor environment are divided into Unit-1, -2 and -3 with depth below surface. In Unit-1 (0-10 mbsf), fresh seawater is circulated, whereas in Unit-3 (>40 mbsf), hot hydrothermal fluid (>150 degrees Celsius) is stored below anhydrite cap. The Unit-2 is the mixing zone between the hydrothermal fluid and seawater. We found that the ?34S value of sulfate in the mixing zone was higher than those expected by simple mixing between seawater sulfate in Unit-1 (-20‰) and the hydrothermal component in Unit-3 (-16‰). The observed 34S-enrichment and decreased sulfate concentration suggest sulfate reduction took place in this hydrothermal system. Based on our model calculation assuming the mixing and reduction, apparent isotope effect for 33?, 34? and 36? are estimated to be -16.5‰, -32.2‰ and -62.5‰, respectively. These large fractionations together with slight D33S enrichment and D36S depletion all suggest that the sulfate reduction is microbial and not thermochemical process. Our numerical simulation also indicates that the sulfate is reduced before mixing with high temperature fluid, probably within the recharge zone of seawater. Based on these results, we will discuss microbial sulfur cycling in this subseafloor environment.

Aoyama, S.; Nishizawa, M.; Takai, K.; Ueno, Y.

2012-12-01

58

Sulfate reducing bacteria in microbial mats: Changing paradigms, new discoveries  

E-print Network

: Sulfate-reducing bacteria; Biofilms; Carbonate precipitation; Lithification; Stromatolites; Microbial mats's 4.6 Ga history (Shen and Buick, 2004). Isotopic evidence indicates that sulfate reduction evolved

59

Barium titanium glycolate: A new barium titanate powder precursor  

SciTech Connect

This paper describes the synthesis and structure of a barium titanium glycolate complex and the calcination into barium titanate preceramic powders that sinter into polycrystalline, tetragonal barium titanate having good dielectric properties.

Day, V.W.; Klemperer, W.G.; Payne, D.A. [Univ. of Nebraska, Lincoln, NE (United States)] [and others] [Univ. of Nebraska, Lincoln, NE (United States); and others

1996-02-01

60

Long term performance of an AMD treatment bioreactor using chemolithoautotrophic sulfate reduction and ferrous iron precipitation under in situ groundwater conditions.  

PubMed

Chemolithoautotrophic sulfate reduction (CSR) was tested to treat natural acid mine drainage influenced groundwaters. The long term behavior was studied for more than 3 years under groundwater conditions (10 °C, autochthonous sulfate reducing bacteria (SRB)) without biomass replenishment in a 190 L bench scale reactor. The process produces water with alkalinity >10 mM. pH can be controlled by p(CO(2)) for all expectable water qualities. SRB were immobilized using an expanded clay bed. After 1.3 years of operation, a constant biomass content and sulfate reduction rate of 0.25-0.30 mmol(so)?(Lh)?¹ were established. The sulfate reduction rate was limited by biomass content. Most of the electrons were used for sulfate reduction (98%). The hydrogen turn over in competing processes like methanogenesis and homoacetogenesis was successfully suppressed by adjusting the sulfate concentration to be >2 mM in the runoff. PMID:22133606

Bilek, F; Wagner, S

2012-01-01

61

Barium release system  

NASA Technical Reports Server (NTRS)

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.

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

1973-01-01

62

Molecular Structure of Barium Chloride  

NSDL National Science Digital Library

Barium Chloride was the byproduct of the discovery of radium by Madame Curie. When refining radium, the final separation resulted in barium chloride and radium chloride. Electrophoresis of barium chloride produces small-scale amounts of barium atom. This can be used for obtaining barium for commercial uses. Applications of barium chloride include stimulating the heart and other muscles for medicinal purposes, and also for softening water. Other uses of barium chloride include the manufacturing of barium salts, as pesticide, pigments, boiler detergent, in purifying sugar, as mordant in dyeing and printing textiles, and in the manufacture of caustic soda, polymers, and stabilizers.

2002-08-15

63

[Determination of the sulfate ion content in antibiotic sulfate salts by a complexometric titration method].  

PubMed

A possibility of assaying antibiotic sulfates, such as gentamicin, kanamycin, monomycin, neomycin, ristomycin, streptomycin, florimycin and polymyxin M sulfates for sulfate ions by titration with barium chloride in the presence of chlorphosphonaso-III, a metal indicator immediately in the salt solutions or after elimination of the cation by means of ion exchange (sulfocation exchange resins in H+-form) was tested. The procedure was shown to be adequate to the classical weight method. PMID:7469396

Kartseva, V D; Lokshin, G B; Libinson, G S; Kruzhkova, N G

1980-12-01

64

Sulfate scale dissolution  

SciTech Connect

This patent describes a method for removing barium sulfate scale. It comprises contacting the scale with an aqueous solution having a pH of about 8 to about 14 and consisting essentially of a chelating agent comprising a polyaminopolycarboxylic acid or salt of such an acid in a concentration of 0.1 to 1.0 M, and anions of a monocarboxylic acid selected form mercaptoacetic acid, hydroxyacetic acid, aminoacetic acid, or salicyclic acid in a concentration of 0.1 to 1.0 M and which is soluble in the solution under the selected pH conditions, to dissolve the scale.

Morris, R.L.; Paul, J.M.

1992-01-28

65

Study of the Mechanisms of Interaction between the Hydrolysis Products of Titanyl Sulfate and Sulfate Lignin  

Microsoft Academic Search

Hydrolysis products of TiOSO4 · 2?2? depending on pH was shown to differently affect an aggregation stability of sulfate lignin. Within the acidic region, these products cause coagulation effect with respect to sulfate lignin, whereas within alkaline region sulfate lignin is the stabilizer preventing the formation and precipitation of the hydrolysis products of titanyl sulfate.

Yu. M. Chernoberezhskii; D. Yu. Mineev; A. B. Dyagileva; A. V. Lorentsson

2002-01-01

66

Tailored Barium Swallow Study  

MedlinePLUS

Tailored Barium Swallow Study The TBS is a special study that is completed in radiology. The test evaluates the mouth and ... where foods and liquids go when a person swallows. It helps clinicians to identify the reasons for ...

67

Beta barium borate (BBO)  

Microsoft Academic Search

The paper contains a review of crystallographic, optical and nonlinear optical properties of beta barium borate (ß-BaB2O4 or BBO) crystal and presents a description of its typical applications in nonlinear optics and quantum electronics.

D. N. Nikogosyan

1991-01-01

68

Barium bright and heavy  

NASA Astrophysics Data System (ADS)

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.

Fromm, Katharina M.

2013-02-01

69

Isotopic Zonation Within Sulfate Evaporite Mineral Crystals Reveal Quantitative Paleoenvironment Details  

NASA Astrophysics Data System (ADS)

Isotopic variations measured within a single crystal of hydrated magnesium sulfate are greater than 30 permil for delta 2-H, almost 10 permil for ?18O in water of hydration; and greater than 3 permil in sulfate oxygen. These results are interpreted to indicate the relative humidity of the system during evaporation (15 to 20 percent in this test case) and constrain the volume of water involved. The theoretical basis of this system is the isotopic fractionation between the species in solution and those precipitated as evaporite salts. Precipitation preferentially accumulates more of the heavy isotopes of sulfur and oxygen in mineral sulfate, relative to sulfate in solution. During the course of mineral growth this leads to successive depletion of the respective heavier isotopes in the residual brine reflected in a parallel trend in successive precipitates or even in successive zones within a single crystal. The change in isotopic composition at any one time during the process, relative to the initial value, can be described by an isotopic version of the Rayleigh Fractionation equation, depending only on the extent of the completion of the process and the relevant fractionation factor. Evaporation preferentially removes isotopically lighter hydrogen and oxygen leading to successive extents of enrichment in the respective heavier isotopes in the residual water. However, the relative effects on hydrogen and oxygen isotopes differs as function of relative humidity [1]. ALL OF THESE CHANGES ARE PRESERVED IN THE MINERAL ISOTOPE COMPOSITIONS. We precipitated barium sulfate from epsomite or gypsum samples, which was reduced at 1450°C in the presence of graphite and glassy carbon in a Finnigan TC/EA to produce CO for O isotopic analysis in a Finnigan 253 mass spectrometer, while a separate subsample was oxidized to SO2 in a Costech Elemental Analyzer. However, to make progress with this approach we needed to make a large number of measurements of hydration water and so we developed a new analytical method [2]. We use a modification of the standard TC/EA continuous-flow protocol to measure both hydrogen and oxygen of water of hydration from the same small sample. We have proved the concept of this new approach by analyzing zones within crystals and individual grains, growing epsomite (magnesium sulfate heptahydrate) in the laboratory and by analysis of natural gypsum evaporites. We are now exploring the effects of varying the controlling parameters. Eventual application to Martian sulfates will reveal amount of water involved in sulfate formation, its isotopic composition(s) and details of the paleo-atmospheric humidity. [1] Gat JR and Gonfiantini R, (Eds) (1981) IAEA Technical Report Series. [2] Rohrssen MK, Brunner B Mielke RE and Coleman M (2008) Analyt. Chem. (in press).

Coleman, M.; Rhorssen, M.; Mielke, R. E.

2008-12-01

70

Monitoring Long-term Trends in Sulfate and Ammonium in US Precipitation: Results from the National Atmospheric Deposition Program\\/National Trends Network  

Microsoft Academic Search

Data from the National Atmospheric Deposition Program\\/National Trends Network (NADP\\/NTN) indicate significant changes have\\u000a occurred in precipitation chemistry and the chemical climate in the United States (US). A Seasonal Kendall Trend (SKT) analysis\\u000a shows statistically significant increases in precipitation ammonium concentrations at 64% of 159 continental US NADP\\/NTN sites\\u000a evaluated from Winter 1985 to Fall 2004 (Dec. 1984 – Nov.

Christopher M. B. Lehmann; Van C. Bowersox; Robert S. Larson; Susan M. Larson

71

Direct reduction of sulfates to sulfur dioxide for isotopic analysis  

Microsoft Academic Search

Direct Reduction of Sulfates to Sulfur Dioxide for Isotopic Analysis I\\/sub n\\/ a previously published method, sulfur dioxide for isotopic analysis was prepared from barium sulfate by thermal decomposition. System has been modified by the addition of a furnace with copper turnings at 600°C. The sulfate is mixed with cuprous oxide and silica, system is evacuated and sample is reduced

Max L. Coleman; Michael P. Moore

1978-01-01

72

Aspiration of barium contrast.  

PubMed

The aspiration of barium contrast is a rare complication that may occur during studies of the digestive tract. Barium is an inert material that can cause anywhere from an asymptomatic mechanical obstruction to serious symptoms of respiratory distress that can result in patient death. We present the case of a 79-year-old male patient in whom we observed the presence of contrast medium residue in the lung parenchyma as an incidental finding during hospitalization. When the patient's medical file was reviewed, images were found of a barium swallow study that the patient had undergone months earlier, and we were able to observe the exact moment of the aspiration of the contrast material. The patient had been asymptomatic since the test. PMID:25309769

Fuentes Santos, Cristina; Steen, Bárbara

2014-01-01

73

Aspiration of Barium Contrast  

PubMed Central

The aspiration of barium contrast is a rare complication that may occur during studies of the digestive tract. Barium is an inert material that can cause anywhere from an asymptomatic mechanical obstruction to serious symptoms of respiratory distress that can result in patient death. We present the case of a 79-year-old male patient in whom we observed the presence of contrast medium residue in the lung parenchyma as an incidental finding during hospitalization. When the patient's medical file was reviewed, images were found of a barium swallow study that the patient had undergone months earlier, and we were able to observe the exact moment of the aspiration of the contrast material. The patient had been asymptomatic since the test. PMID:25309769

Fuentes Santos, Cristina; Steen, Barbara

2014-01-01

74

Observed Barium Emission Rates  

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

75

Spatial and temporal variability of precipitation for selected regions of New York State and relationship to variability in sulfate deposition measurements  

SciTech Connect

The preliminary results are presented of a study aimed at quantifying the variability in precipitation data and its role in the modeling of acidic deposition processes. The character of this variability for various regions of New York State is assessed over a 30-year period, with emphasis on the Adirondack region. Spatial and temporal means as well as coefficients of variation are presented. Of the five regions where precipitation data are investigated, the Adirondacks have the greatest overall variability, around 23 percent, while Long Island has the least, about 17 percent. A proportionality factor, based on the coefficient of variation, is suggested to account for the precipitation variability in achieving targeted wet deposition threshold values.

Pagnotti, V.; Rao, S.T.

1986-04-01

76

Semiconducting barium titanate  

Microsoft Academic Search

Barium titanate, which is well known as a basic ferroelectric material, is also of interest when doped because of the interaction between semiconductivity and ferroelectricity. The resistance of blocking layers at surfaces and grain-boundaries is governed mainly by the ferroelectric properties, so that a resistance jump of four decades is observed on heating above the Curie temperature. A survey of

W. Heywang

1971-01-01

77

Yielding Unexpected Results: Precipitation of Ba[subscript3](PO[subscript4])[subscript2] and Implications for Teaching Solubility Principles in the General Chemistry Curriculum  

ERIC Educational Resources Information Center

Precipitation of barium phosphate from aqueous solutions of a barium salt and a phosphate salt forms the basis for a number of conclusions drawn in general chemistry. For example, the formation of a solid white precipitate is offered as evidence that barium phosphate is insoluble. Furthermore, analysis of the supernatant is used to illustrate the…

Hazen, Jeffery L.; Cleary, David A.

2014-01-01

78

Methods for producing monodispersed particles of barium titanate  

DOEpatents

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.

Hu, Zhong-Cheng (Knoxville, TN)

2001-01-01

79

An agarose gel electrophoretic method for analysis of sulfated glycosaminoglycans of cultured cells.  

PubMed

Agarose disc gel electrophoresis has been adapted to achieve the separation of the major sulfated glycosaminoglycans produced by cells in culture. By use of buffers containing barium ion, mixtures of chondroitin sulfate, dermatan sulfate, and heparan sulfate are well resolved into discrete bands. The technique can be used preparatively as well as analytically to separate quantities of glycosaminoglycans up to a milligram in a 6-mm diameter gel. PMID:9762132

Funderburgh, J L; Chandler, J W

1978-12-01

80

Silicosis in barium miners.  

PubMed Central

Four men who mined barytes in Scotland and who developed pneumoconiosis are described. Three developed progressive massive fibrosis, from which two died; and one developed a nodular simple pneumoconiosis after leaving the industry. The radiological and pathological features of the men's lungs were those of silicosis and high proportions of quartz were found in two of them post mortem. The quartz was inhaled from rocks associated with the barytes in the mines. The features of silicosis in barium miners are contrasted with the benign pneumoconiosis, baritosis, that occurs in workers exposed to crushed and ground insoluble barium salts. Diagnostic difficulties arise when silicosis develops in workers mining minerals known to cause a separate and benign pneumoconiosis. These difficulties are compounded when, as not infrequently happens, the silicotic lesions develop or progress after exposure to quartz has ceased. Images PMID:3787542

Seaton, A; Ruckley, V A; Addison, J; Brown, W R

1986-01-01

81

Properties of Semiconductive Barium Titanates  

Microsoft Academic Search

The resistivity of barium titanate which is usually of the order of 109˜1012 ohm-cm, may be remarkably reduced with suitable control in valency. The valency-controlled barium titanate, whose resistivity is of the order of 10˜104 ohm-cm at room temperature, shows anomalous positive character in the temperature dependency of the resistivity. For example, the resistivity of barium titanate containing 0.1 mol.

Osamu Saburi

1959-01-01

82

Barium uranyl diphosphonates  

SciTech Connect

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 mineralizing agent and a ligand.

Nelson, Anna-Gay D., E-mail: nelsoa@umich.edu [Department of Civil Engineering and Geological Sciences and Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556 (United States); Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109-1005 (United States); Alekseev, Evgeny V. [Institute of Energy and Climate Research (IEK-6), Forschungszentrum Juelich Wilhelm-Johnen-Strasse, Juelich 52428 (Germany); Ewing, Rodney C. [Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109-1005 (United States); Albrecht-Schmitt, Thomas E. [Department of Civil Engineering and Geological Sciences and Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556 (United States)

2012-08-15

83

Removal of carbon dioxide by reactive crystallization in a scrubber—kinetics of barium carbonate crystals  

Microsoft Academic Search

A bubble column scrubber was utilized to remove simulated CO2 waste gas under a constant pH value. Using barium chloride solution as an absorbent reacting with CO2-gas in the scrubber under an alkaline solution condition, precipitates of barium carbonate were formed during the operation. Measured crystal size distributions at a given time were used to calculate the growth rate of

Pao-Chi Chen; K. L. Kou; H. K. Tai; S. L. Jin; C. L. Lye; C. Y. Lin

2002-01-01

84

Barium uranyl diphosphonates  

NASA Astrophysics Data System (ADS)

Three Ba2+/UO22+ 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 °C. These compounds, Ba[UO2[CH2(PO3)2]·1.4H2O (Ba-1), Ba3[(UO2)4(CH2(PO3)2)2F6]·6H2O (Ba-2), and Ba2[(UO2)2(CH2(PO3)2)F4]·5.75H2O (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 UO5F2 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 [UO2[CH2(PO3)2]2- sheets. The interlayer space of the structures is occupied by Ba2+, which, along with the fluoride ion, mediates the structure formed and maintains overall charge balance.

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

2012-08-01

85

[Regulation of sulfates, hydrogen sulfide and heavy metals in technogenic reservoirs by sulfate-reducing bacteria].  

PubMed

Sulfate-reducing bacteria Desulfovibrio desulfuricans Ya-11 in the presence of sulfates and organic compounds in the medium reduce sulfates to hydrogen sulfide (dissimilatory sulfate reduction). Heavy metals in concentration over 2 mM inhibit this process. Pb2+, Zn2+, Ni2+, Co2+, Fe2+ and Cd2+ ions in concentration 1-1.5 mM display insignificant inhibiting effect on sulfate reduction process, and metals precipitate in the form of sulfides. At concentrations of heavy metals 2-3 mM one can observe a decrease of sulfates reduction intensity, and a percent of metals binding does not exceed 72%. Obtained results give reason to confirm, that sulfate-reducing bacteria play an important role in regulation of the level of sulfates, hydrogen sulfide and heavy metals in reservoirs and they may be used for purification of water environment from these compounds. PMID:21598657

Hudz', S P; Peretiatko, T B; Moroz, O M; Hnatush, S O; Klym, I R

2011-01-01

86

Single atom barium sources for EXO barium tagging development  

NASA Astrophysics Data System (ADS)

Barium tagging, the extraction and identification of the ^136 Xe double beta decay daughter product, would allow the Enriched Xenon Observatory (EXO) experiment to eliminate almost all backgrounds. The collaboration has made much progress in developing an ion probe to extract a barium ion from either liquid or gas xenon and an ion trap to identify a single barium ion. Yet the true efficiencies of these methods cannot be known until a source of single barium ions is available. I will talk about the Ba source R&D efforts of the EXO collaboration; they include 1) using the alpha recoil of ^148Gd on a thin layer of BaF2, 2) using an electrostatic gate to select single atoms from a Ba ion beam, and 3) using chemistry to isolate ^ 137Cs which then beta decays to Ba^+. )

Yen, Yung-Ruey

2010-02-01

87

Discovery of the Barium Isotopes  

E-print Network

Thirty-eight barium isotopes have so far been observed; the discovery of these isotopes is discussed. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented.

A. Shore; A. Fritsch; J. Q. Ginepro; M. Heim; A. Schuh; M. Thoennessen

2009-08-13

88

Barium light source method and apparatus  

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

89

The Exotic Barium Bismuthates  

NASA Astrophysics Data System (ADS)

We review the remarkable properties, including superconductivity, charge-density-wave ordering and metal-insulator transitions, of lead- and potassium-doped barium bismuthate. We will discuss some of the early theoretical studies of these systems. Our recent theoretical work, on the negative-U, extended-Hubbard model for these systems, will also be described. Both the large- and intermediate-U regimes of this model were examined, using mean-field and random-phase approximations, particularly with a view to fitting various experimental properties of these bismuthates. On the basis of our studies, we point out possibilities for exotic physics in these systems. We also emphasize the different consequences of electronic and phonon-mediated mechanisms for the negative U. We show that, for an electronic mechanism, the semiconducting phases of these bismuthates must be unique, with their transport properties dominated by charge ±2e Cooperon bound states. This can explain the observed difference between the optical and transport gaps. We propose other experimental tests for this novel mechanism of charge transport and comment on the effects of disorder.

Taraphder, A.; Pandit, Rahul; Krishnamurthy, H. R.; Ramakrishnan, T. V.

90

Barium Stars and Thermohaline Mixing  

SciTech Connect

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.

Husti, Laura [Dipartimento di Fisica Generale, Universita di Torino, Via Pietro Giuria 1, 10125 Turin (Italy)

2008-01-24

91

Observations on the histochemistry of barium  

Microsoft Academic Search

The histochemistry of barium was investigated with particular reference to the use of sodium rhodizonate. It was found that not all batches of sodium rhodizonate were able to effect satisfactory visualisation of barium deposits. None of the other histological parameters considered gave a consistent indication of the presence of barium.

A. J. Chaplin; E. L. T. Turner

1983-01-01

92

Refractory concrete based on barium aluminate–barium zirconate cements for steel-making industries  

Microsoft Academic Search

Five refractory cement mixes were prepared from different proportions of barite, zirconia and calcined alumina by sintering at 1500–1550°C for 3h. The obtained cements were composed of barium aluminate and barium zirconate minerals in addition to comparable proportions of di-barium silicate.Cement mix prepared from 70wt.% barite, 10wt.% zirconia and 20wt.% alumina and containing comparable proportions of barium aluminate and barium

N. M. Khalil

2005-01-01

93

Arsenious oxide — a primary standard for the iodometric estimation of lead and barium  

Microsoft Academic Search

A volumetric method for the estimation of lead and barium, based on precipitation of the respective metal chromate and subsequent iodometric titration of the chromic acid against standard As2O3 solution in a suitably adjustedph range, is described. Estimation of Ag, Sr and Tl on similar lines is suggested.

B. R. Sant

1955-01-01

94

Distribution and source of barium in ground water at Cattaraugus Indian Reservation, southwestern New York  

USGS Publications Warehouse

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)

Moore, R.B.; Staubitz, W.W.

1984-01-01

95

Chinese hamster ovary cell mutants defective in heparan sulfate biosynthesis  

SciTech Connect

The authors have isolated Chinese hamster ovary cell mutants defective in proteoglycan synthesis by radiographic screening for cells unable to incorporate TVSO4 into acid-precipitable material. Some mutants did not incorporate TVSO4 into acid-precipitable material, whereas others incorporated about 3-fold less radioactivity. HPLC anion exchange chromatographic analysis of radiolabelled glycosaminoglycans isolated from these mutants revealed many are defective in heparan sulfate biosynthesis. Mutants 803 and 677 do not synthesize heparan sulfate, although they produce chondroitin sulfate: strain 803 makes chondroitin sulfate normally, whereas 677 overaccumulates chondroitin sulfate by a factor of three. These mutants fall into the same complementation group, suggesting that the mutations are allelic. A second group of heparan sulfate biosynthetic mutants, consisting of cell lines 625, 668 and 679, produce undersulfated heparan sulfate and normal chondroitin sulfate. Treatment of the chains with nitrous acid should determine the position of the sulfate groups along the chain. These mutants may define a complementation group that is defective in the enzymes which modify the heparan sulfate chain. To increase the authors repertoire of heparan sulfate mutants, they are presently developing an in situ enzyme assay to screen colonies replica plated on filter discs for sulfotransferase defects.

Bame, K.J.; Kiser, C.S.; Esko, J.D.

1987-05-01

96

Rapid variablity of Cenozoic weawater sulfate concentrations  

NASA Astrophysics Data System (ADS)

Fluid inclusion data suggest that the composition of major elements in seawater changes slowly over geological time scales. This view contrasts with high resolution isotope data that imply more rapid fluctuations of seawater chemistry. We use a non-steady state box model of the global sulfur cycle to show that the marine S-isotope record can be explained by variable marine sulfate concentrations triggered by basin scale evaporite precipitation/dissolution events. We propose that the deep time evolution of seawater sulfate concentrations is best characterized by long phases of stasis, punctuated by short intervals of rapid change. This has far reaching implications as sulfate concentrations affect several important biological processes including carbonate mineralogy, microbially mediated organic matter remineralization, sedimentary phosphorous regeneration, and nitrogen fixation. These changes are likely to impact ocean productivity, and the the global carbon cycle. Moreover, because the ocean is a major source for sulfate aerosols, lower marine sulfate concentrations could have affected atmospheric aerosol chemistry as well. Thus, times of high sulfate concentrations correlate with an increased aerosol load and global cooling, whereas times of low marine sulfate concentrations correspond with greenhouse periods. Specifically, the rapid rise of the marine sulfate concentrations during the Early Eocene likely increased the aerosol load in the atmosphere, which may have contributed to the demise of the Eocene Climatic Optimum and the onset of the longterm Cenozoic cooling trend.

Wortmann, U. G.; Paytan, A.

2012-12-01

97

Novel Thermally Stable Poly (vinyl chloride) Composites for Sulfate Removal  

EPA Science Inventory

BaCO3 dispersed PVC composites were prepared through a polymer re-precipitation method. The composites were tested for sulfate removal using rapid small scale column test (RSSCT) and found to significantly reduce sulfate concentration. The method was extended to synthe...

98

40 CFR 721.10011 - Barium calcium manganese strontium oxide.  

...2014-07-01 false Barium calcium manganese strontium oxide. 721.10011 Section...Substances § 721.10011 Barium calcium manganese strontium oxide. (a) Chemical substance...substance identified as barium calcium manganese strontium oxide (PMN...

2014-07-01

99

The L equals 6.7 quiet time barium shaped charge injection experiment 'Chachalaca'  

NASA Technical Reports Server (NTRS)

Near dawn on October 9, 1972, UT, a barium plasma injection experiment was carried out from Poker Flat, Alaska, during quiet magnetic conditions (Kp equals 1+). The visible plasma flux tube produced was more diffuse than the flux tubes in previous experiments, but it could be tracked for 30 min out to an altitude of 2.5 earth radii. The flux tube remained integral for about 20 min, when a single striation separated from the main streak. Comparisons of the observed flux tube orientation with theoretical field models show no significant deviations ascribable to field-aligned currents. Cross-field drift rates of the foot of the flux tube indicate an E field of approximately 7 mV/m at 200-km altitude. Although an attempt was made via a jet aircraft flight, barium ions were not detected in the southern conjugate region. No energetic particle precipitation phenomena were observed which could be ascribed to the barium plasma injection.

Wescott, E. M.; Stenbaek-Nielsen, H. C.; Davis, T. N.; Rieger, E. P.; Peek, H. M.; Bottoms, P. J.

1975-01-01

100

Improved spectrophotometric analysis of barium styphnate  

Microsoft Academic Search

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

N. E. Brown; J. A. Blasi

1983-01-01

101

Improved spectrophotometric analysis of barium styphnate  

Microsoft Academic Search

A spectrophotometric procedure to determine the purity of barium styphnate monohydrate based upon the absorbance of the styphnate ion at 326 and 413 nm has been developed. The purity is determined by comparing the absorbance of the styphnate ion in barium styphnate and styphnic acid at pH 6.8. Our investigation has shown that the molar absorptivities and maxima of the

Norman E. Brown; Jane A. Blasi

1985-01-01

102

Barium granuloma of the transverse colon.  

PubMed Central

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

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

1978-01-01

103

REMOVAL OF BARIUM AND RADIUM FROM GROUNDWATER  

EPA Science Inventory

A research project was undertaken to investigate processes for removing barium and radium from drinking water. Special emphasis was placed on ion exchange processes that can be used without adding large concentrations of sodium to the water. The wastes from radium and barium remo...

104

Sulfate in fetal development  

Microsoft Academic Search

Sulfate (SO42?) is an important nutrient for human growth and development, and is obtained from the diet and the intra-cellular metabolism of sulfur-containing amino acids, including methionine and cysteine. During pregnancy, fetal tissues have a limited capacity to produce sulfate, and rely on sulfate obtained from the maternal circulation. Sulfate enters and exits placental and fetal cells via transporters on

Paul A. Dawson

2011-01-01

105

Crystallization of Chicken Egg White Lysozyme from Sulfate Salts  

NASA Technical Reports Server (NTRS)

It has been "known" that chicken egg white lysozyme does not crystallize from sulfate, particularly ammonium sulfate, salts, but instead gives amorphous precipitates. This has been the basis of several studies using lysozyme comparing macromolecule crystal nucleation and amorphous precipitation. Recently Ries-Kautt et al (Acta Cryst D50, (1994) 366) have shown that purified isoionic CEWL could be crystallized from low concentrations of sulfate at basic pH, and we subsequently showed that in fact CEWL could be purified in both the tetragonal and orthorhombic forms using ammonium sulfate over the pH range 4.0 to 7.8 (Acta Cryst D53, (1997) 795). We have now extended these observations to include a range of common sulfate salts, specifically sodium, potassium, rubidium, magnesium, and manganese sulfates. In all cases but the manganese sulfates both the familiar tetragonal and orthorhombic forms were obtained, with unit cell dimensions close to those known for the "classic" sodium chloride crystallized forms. Manganese sulfate has only yielded orthorhombic crystals to date. All crystallizations were carried out using low (typically less than or equal to 6 M) salt and high (greater than approximately 90 mg/ml) protein concentrations. As with ammonium sulfate, the tetragonal - orthorhombic phase shift appears to be a function of both the temperature and the protein concentration, with higher temperatures and concentrations favoring the orthorhombic and lower the tetragonal form. The phase change range is somewhat reduced for the sulfate salts, depending upon conditions being typically between approximately 15 - 20 C. Both the magnesium and manganese sulfates gave crystals at salt concentrations over 0.6 M as well, with magnesium sulfate giving a very slowly nucleating and growing hexagonal form. A triclinic crystal form, characterized by aggressively small crystals (typically 0.1 mm in size) has been occasionally obtained from ammonium sulfate. Finally, preliminary spot solubility determinations have suggested that in some cases the solubility increases with increasing salt concentrations.

Forsythe, Elizabeth; Pusey, Marc

1998-01-01

106

Sulfate Adsorption on Goethite.  

PubMed

Recent spectroscopic work has suggested that only one surface species of sulfate is dominant on hematite. Sulfate is therefore a very suitable anion to test and develop adsorption models for variable charge minerals. We have studied sulfate adsorption on goethite covering a large range of sulfate concentrations, surface coverages, pH values, and electrolyte concentrations. Four different techniques were used to cover the entire range of conditions. For characterization at low sulfate concentrations, below the detection limit of sulfate with ICP-AES, we used proton-sulfate titrations at constant pH. Adsorption isotherms were studied for the intermediate sulfate concentration range. Acid-base titrations in sodium sulfate and electromobility were used for high sulfate concentrations. All the data can be modeled with one adsorbed species if it is assumed that the charge of adsorbed sulfate is spatially distributed in the interface. The charge distribution of sulfate follows directly from modeling the proton-sulfate adsorption stoichiometry since this stoichiometry is independent of the intrinsic affinity constant of sulfate. The charge distribution can be related to the structure of the surface complex by use of the Pauling bond valence concept and is in accordance with the microscopic structure found by spectroscopy. The intrinsic affinity constant follows from the other measurements. Modeling of the proton-ion stoichiometry with the commonly used 2-pK models, where adsorbed ions are treated as point charges, is possible only if at least two surface species for sulfate are used. Copyright 1999 Academic Press. PMID:10502384

Rietra; Hiemstra; van Riemsdijk WH

1999-10-15

107

Hydrometallurgical process for recovering iron sulfate and zinc sulfate from baghouse dust  

SciTech Connect

A process for recovering zinc/rich and iron-rich fractions from the baghouse dust that is generated in various metallurgical operations, especially in steel-making and other iron-making plants, comprises the steps of leaching the dust by hot concentrated sulfuric acid so as to generate dissolved zinc sulfate and a precipitate of iron sulfate, separating the precipitate from the acid by filtration and washing with a volatile liquid, such as methanol or acetone, and collecting the filtered acid and the washings into a filtrate fraction. The volatile liquid may be recovered distillation, and the zinc may be removed from the filtrate by alternative methods, one of which involves addition of a sufficient amount of water to precipitate hydrated zinc sulfate at 10.degree. C., separation of the precipitate from sulfuric acid by filtration, and evaporation of water to regenerate concentrated sulfuric acid. The recovery of iron may also be effected in alternative ways, one of which involves roasting the ferric sulfate to yield ferric oxide and sulfur trioxide, which can be reconverted to concentrated sulfuric acid by hydration. The overall process should not generate any significant waste stream.

Zaromb, Solomon (95706 William Dr., Hinsdale, IL 60521); Lawson, Daniel B. (925 Putnam Dr., Lockport, IL 60441)

1994-01-01

108

Acute barium nitrate intoxication treated by hemodialysis.  

PubMed

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. PMID:15675995

Bahlmann, H; Lindwall, R; Persson, H

2005-01-01

109

Barium Isotopes in Single Presolar Grains  

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

110

Sulfate in fetal development.  

PubMed

Sulfate (SO(4)(2-)) is an important nutrient for human growth and development, and is obtained from the diet and the intra-cellular metabolism of sulfur-containing amino acids, including methionine and cysteine. During pregnancy, fetal tissues have a limited capacity to produce sulfate, and rely on sulfate obtained from the maternal circulation. Sulfate enters and exits placental and fetal cells via transporters on the plasma membrane, which maintain a sufficient intracellular supply of sulfate and its universal sulfonate donor 3'-phosphoadenosine 5'-phosphosulfate (PAPS) for sulfate conjugation (sulfonation) reactions to function effectively. Sulfotransferases mediate sulfonation of numerous endogenous compounds, including proteins and steroids, which biotransforms their biological activities. In addition, sulfonation of proteoglycans is important for maintaining normal structure and development of tissues, as shown for reduced sulfonation of cartilage proteoglycans that leads to developmental dwarfism disorders and four different osteochondrodysplasias (diastrophic dysplasia, atelosteogenesis type II, achondrogenesis type IB and multiple epiphyseal dysplasia). The removal of sulfate via sulfatases is an important step in proteoglycan degradation, and defects in several sulfatases are linked to perturbed fetal bone development, including mesomelia-synostoses syndrome and chondrodysplasia punctata 1. In recent years, interest in sulfate and its role in developmental biology has expanded following the characterisation of sulfate transporters, sulfotransferases and sulfatases and their involvement in fetal growth. This review will focus on the physiological roles of sulfate in fetal development, with links to human and animal pathophysiologies. PMID:21419855

Dawson, Paul A

2011-08-01

111

Small barium rail gun for plasma injection.  

PubMed

A small rail gun with a barium electrode can be operated at higher than one shot per second to produce more than 2x10(16) barium ions with energy 10-20 eV. The operation of the gun takes advantage of the external magnetic field for cross-field plasma injection into a trap. Up to 7 kG of the magnetic field examined, the gun performance improves with the increased magnetic field strength. PMID:18647050

Kiwamoto, Y

1980-03-01

112

Pulsating aurora induced by upper atmospheric barium releases  

NASA Technical Reports Server (NTRS)

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.

Deehr, C.; Romick, G.

1977-01-01

113

Heparan Sulfate Proteoglycans  

PubMed Central

Heparan sulfate proteoglycans are found at the cell surface and in the extracellular matrix, where they interact with a plethora of ligands. Over the last decade, new insights have emerged regarding the mechanism and biological significance of these interactions. Here, we discuss changing views on the specificity of protein–heparan sulfate binding and the activity of HSPGs as receptors and coreceptors. Although few in number, heparan sulfate proteoglycans have profound effects at the cellular, tissue, and organismal level. PMID:21690215

Sarrazin, Stephane; Lamanna, William C.; Esko, Jeffrey D.

2011-01-01

114

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

NASA Technical Reports Server (NTRS)

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.

Ota, K.; Conger, W. L.

1977-01-01

115

The use of stable sulfur and oxygen isotope ratios for interpreting the mobility of sulfate in aerobic forest soils  

Microsoft Academic Search

The isotope compositions of sulfate in bulk precipitation near Munich (Germany) and of seepage water and soil sulfate in five acid forest soils representative of southern Germany were determined in order to ascertain the sources and dynamics of sulfur. While the ?34 S-values of inorganic sulfate in soil solution and solid phases were found to be nearly identical to those

H. R. Krouse; P FRITZ; J PRIETZEL

1995-01-01

116

Degradation process of lead chromate in paintings by Vincent van Gogh studied by means of spectromicroscopic methods. 4. Artificial aging of model samples of co-precipitates of lead chromate and lead sulfate.  

PubMed

Previous investigations about the darkening of chrome yellow pigments revealed that this form of alteration is attributable to a reduction of the original Cr(VI) to Cr(III), and that the presence of sulfur-containing compounds, most often sulfates, plays a key role during this process. We recently demonstrated that different crystal forms of chrome yellow pigments (PbCrO(4) and PbCr(1-x)S(x)O(4)) are present in paintings by Vincent van Gogh. In the present work, we show how both the chemical composition and the crystalline structure of lead chromate-based pigments influence their stability. For this purpose, oil model samples made with in-house synthesized powders of PbCrO(4) and PbCr(1-x)S(x)O(4) were artificially aged and characterized. We observed a profound darkening only for those paint models made with PbCr(1-x)S(x)O(4), rich in SO(4)(2-) (x ? 0.4), and orthorhombic phases (>30 wt %). Cr and S K-edge micro X-ray absorption near edge structure investigations revealed in an unequivocal manner the formation of up to about 60% of Cr(III)-species in the outer layer of the most altered samples; conversely, independent of the paint models' chemical composition, no change in the S-oxidation state was observed. Analyses employing UV-visible diffuse reflectance and Fourier transform infrared spectroscopy were performed on unaged and aged model samples in order to obtain additional information on the physicochemical changes induced by the aging treatment. PMID:23051631

Monico, Letizia; Janssens, Koen; Miliani, Costanza; Van der Snickt, Geert; Brunetti, Brunetto Giovanni; Cestelli Guidi, Mariangela; Radepont, Marie; Cotte, Marine

2013-01-15

117

Wnts, Signaling and Sulfates  

NSDL National Science Digital Library

Questions remain about the signaling pathways that control pattern formation during development. Blair describes how sulfated glycosaminoglycans affect several developmentally important signaling pathways, including Wnt-Wingless, Fibroblast growth factor, Hedgehog, and Bone morphogenetic protein-4 signaling. A new secreted sulfatase, Qsulf1, regulates the sensitivity of vertebrate cells to Wnts, possibly by modifying the sulfation of glycosaminoglycans.

Seth S. Blair (University of Wisconsin;Department of Zoology REV)

2001-09-25

118

Cholesterol, Sulfate, and Heart Disease  

E-print Network

Cholesterol, Sulfate, and Heart Disease Stephanie Seneff Wise Tradi0ons Workshop, London." -- Orville Wright #12;Outline · Introduc0on · Cholesterol sulfate · Blood clots #12;· Cholesterol sulfate supplies

Seneff, Stephanie

119

Bacterial sulfate reduction limits natural arsenic contamination in groundwater  

NASA Astrophysics Data System (ADS)

Natural arsenic contamination of groundwater, increasingly recognized as a threat to human health worldwide, is characterized by arsenic concentrations that vary sharply over short distances. Variation in arsenic levels in the Mahomet aquifer system, a regional glacial aquifer in central Illinois, appears to arise from variable rates of bacterial sulfate reduction in the subsurface, not differences in arsenic supply. Where sulfate-reducing bacteria are active, the sulfide produced reacts to precipitate arsenic, or coprecipitate it with iron, leaving little in solution. In the absence of sulfate reduction, methanogenesis is the dominant type of microbial metabolism, and arsenic accumulates to high levels.

Kirk, Matthew F.; Holm, Thomas R.; Park, Jungho; Jin, Qusheng; Sanford, Robert A.; Fouke, Bruce W.; Bethke, Craig M.

2004-11-01

120

Sulfur isotopes as indicators of amended bacterial sulfate reduction processes influencing field scale uranium bioremediation.  

PubMed

Aqueous uranium (U(VI)) concentrations in a contaminated aquifer in Rifle Colorado have been successfully lowered through electron donor amended bioreduction. Samples collected during the acetate amendment experiment were analyzed for aqueous concentrations of Fe(ll), sulfate, sulfide, acetate, U(VI), and delta(34)S of sulfate and sulfide to explore the utility of sulfur isotopes as indicators of in situ acetate amended sulfate and uranium bioreduction processes. Enrichment of up to 7% per hundred in delta(34)S of sulfate in down-gradient monitoring wells indicates a transition to elevated bacterial sulfate reduction. A depletion in Fe(II), sulfate, and sulfide concentrations atthe height of sulfate reduction, along with an increase in the delta(34)S of sulfide to levels approaching the delta(34)S values of sulfate, indicates sulfate limited conditions concurrent with a rebound in U(VI) concentrations. Upon cessation of acetate amendment, sulfate and sulfide concentrations increased, while delta(34)S values of sulfide returned to less than -20% per hundred and sulfate delta(34)S decreased to near-background values, indicating lower levels of sulfate reduction accompanied by a corresponding drop in U(VI). Results indicate a transition between electron donor and sulfate-limited conditions at the height of sulfate reduction and suggest stability of biogenic FeS precipitates following the end of acetate amendment. PMID:19031870

Druhan, Jennifer L; Conrad, Mark E; Williams, Kenneth H; N'Guessan, Lucie; Long, Philip E; Hubbard, Susan S

2008-11-01

121

On the suppression of superconducting phase formation in YBCO materials by templated synthesis in the presence of a sulfated biopolymer  

NASA Astrophysics Data System (ADS)

The use of biopolymers as templates to control superconductor crystallization is a recent phenomenon and is generating a lot of interest both from the superconductor community and in materials chemistry circles. This work represents a critical finding in the use of such biopolymers, in particular the contraindicatory nature of sulfur when attempting to affect a morphologically controlled synthesis. Synthesis of superconducting nanoparticles was attempted using carrageenan as a morphological template. Reactive sulfate groups on the biopolymer prevent this, producing instead significant quantities of barium sulfate nanotapes. By substituting the biopolymer for structurally analogous, non-sulfated agar, we show that superconducting nanoparticles could be successfully synthesized.

Smith, Elliott; Schnepp, Zoe; Wimbush, Stuart C.; Hall, Simon R.

2008-11-01

122

Precipitation Recycling  

NASA Technical Reports Server (NTRS)

The water cycle regulates and reflects natural variability in climate at the regional and global scales. Large-scale human activities that involve changes in land cover, such as tropical deforestation, are likely to modify climate through changes in the water cycle. In order to understand, and hopefully be able to predict, the extent of these potential global and regional changes, we need first to understand how the water cycle works. In the past, most of the research in hydrology focused on the land branch of the water cycle, with little attention given to the atmospheric branch. The study of precipitation recycling which is defined as the contribution of local evaporation to local precipitation, aims at understanding hydrologic processes in the atmospheric branch of the water cycle. Simply stated, any study on precipitation recycling is about how the atmospheric branch of the water cycle works, namely, what happens to water vapor molecules after they evaporate from the surface, and where will they precipitate?

Eltahir, Elfatih A. B.; Bras, Rafael L.

1996-01-01

123

Improved spectrophotometric analysis of barium styphnate  

SciTech Connect

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.

Brown, N E; Blasi, J A

1983-01-01

124

CARBONATION OF BARIUM SULFIDE IN A FOAM-BED REACTOR  

Microsoft Academic Search

Carbonation of barium sulfide to barium carbonate has been experimentally investigated in a foam-bed reactor. The variables studied are height of foam bed, initial concentration of barium sulfide in aqueous solution, gas flow rate, concentration of carbon dioxide in mixture with nitrogen, and surfactant concentration in the aqueous solution. The results indicate that the conversion in the reactor increases with

Amit A. Gaikwad; Niyantha Challapalli; Ashok N. Bhaskarwar

2010-01-01

125

Incorporation of /sup 35/S-sulfate and /sup 3/H-glucosamine into heparan and chondroitin sulfates during the cell cycle of B16-F10 cells  

SciTech Connect

Changes in glycosaminoglycan composition occurring during the cell cycle were determined in B16-F10 cells sorted flow cytometrically with respect to DNA content. Incorporation of /sup 35/S-sulfate into heparan sulfate and chondroitin sulfate of unsorted and G1,S, and G2 +M sorted cells was determined following chondroitinase ABC or nitrous acid treatment; the incorporation into surface material was measured as the difference between the radioactivity of control and trypsin-treated cells. Incorporation of /sup 35/S-sulfate and /sup 3/H-glucosamine into cetyl pyridinium chloride (CPC)-precipitable material was characterized before and after chondroitinase or nitrous acid treatment by Sephadex G50 chromatography. Long-term (48 h) and short-term (1 h) labeling studies demonstrate that (a) the amount of total cellular chondroitin sulfate is greater than that of heparan sulfate, with larger amounts of unsulfated heparan than chondroitin being present; (b) the rate of turnover of heparan sulfate is greater than that of chondroitin sulfate; (c) greatest short-term incorporation of 3H-glucosamine into CPC-precipitable material occurs during S phase; and (d) the rate of turnover of both heparan sulfate and chondroitin sulfate is decreased in S phase relative to G1 and G2 + M.

Blair, O.C.; Sartorelli, A.C.

1984-05-01

126

Gas hydrate decomposition and migration of the sulfate/methane transition zone recorded by authigenic barite in cold seep sediments  

NASA Astrophysics Data System (ADS)

After deposition of sediments a whole suite of geochemical/biogeochemical and transport processes - subsumed under the term early diagenesis - can potentially alter the primary sediment composition. Post-depositional overprint is not only restricted to the topmost part of the sediment but well extends into more deeply buried sediments. A biogeochemical reaction front which is of particular importance for deep post-depositional alteration is the so-called sulfate/methane transition zone (SMTZ) where the anaerobic oxidation of methane (AOM) by sulfate occurs. This front is often located several meters to several tens of meters within the sediment and can heavily impact a number of sedimentary components and attributes - like carbonates, barite, iron oxide and iron sulfide minerals as well as rock magnetic properties (e.g., magnetic susceptibility). In this way the primary sediment composition is distinctly altered several thousands to tens of thousands of years after deposition. Identifying and quantifying such diagenetic overprint is of the utmost importance to accurately interpret the sedimentary record. In marine environments affected by hydrocarbon seepage and/or the presence of gas hydrates the geochemical zonation is often significantly condensed and the sulfate/methane transition zone is typically located close to the sediment surface - in this way impacting the initial sediment composition at relatively shallow depth. While the process of AOM induces the destruction of several primary sediment components it also goes along with the diagenetic formation of secondary signals. One of these diagenetically formed compounds is authigenic barite which precipitates slightly above the SMTZ. We demonstrate that - following the approach of Dickens (2001) - authigenic barite can be a valuable geochemical proxy to trace the downward migration of the SMTZ over time as a result of the decomposition of gas hydrates and/or a decrease in the upward flux of hydrocarbons. Reference Dickens, G.R. (2001) Sulfate profiles and barium fronts in sediment on the Blake Ridge: Present and past methane fluxes through a large gas hydrate reservoir. Geochim. Cosmochim. Acta, 65, 529-543.

Kasten, S.; Hensen, C.; Spiess, V.; Blumenberg, M.; Schneider, R. R.

2010-12-01

127

Uranium Immobilization by Sulfate-reducing Biofilms  

SciTech Connect

Hexavalent uranium [U(VI)] was immobilized using biofilms of the sulfate-reducing bacterium (SRB) Desulfovibrio desulfuricans G20. The biofilms were grown in flat-plate continuous-flow reactors using lactate as the electron donor and sulfate as the electron acceptor. U(VI) was continuously fed into the reactor for 32 weeks at a concentration of 126 íM. During this time, the soluble U(VI) was removed (between 88 and 96% of feed) from solution and immobilized in the biofilms. The dynamics of U immobilization in the sulfate-reducing biofilms were quantified by estimating: (1) microbial activity in the SRB biofilm, defined as the hydrogen sulfide (H2S) production rate and estimated from the H2S concentration profiles measured using microelectrodes across the biofilms; (2) concentration of dissolved U in the solution; and (3) the mass of U precipitated in the biofilm. Results suggest that U was immobilized in the biofilms as a result of two processes: (1) enzymatically and (2) chemically, by reacting with microbially generated H2S. Visual inspection showed that the dissolved sulfide species reacted with U(VI) to produce a black precipitate. Synchrotron-based U L3-edge X-ray absorption near edge structure (XANES) spectroscopy analysis of U precipitated abiotically by sodium sulfide indicated that U(VI) had been reduced to U(IV). Selected-area electron diffraction pattern and crystallographic analysis of transmission electron microscope lattice-fringe images confirmed the structure of precipitated U as being that of uraninite.

Beyenal, Haluk; Sani, Rajesh K.; Peyton, Brent M.; Dohnalkova, Alice; Amonette, James E.; Lewandowski, Zbigniew

2004-04-01

128

59 FR- Drinking Water; National Primary Drinking Water Regulations Sulfate; National Primary Drinking...  

Federal Register 2010, 2011, 2012, 2013

...fossil fuels are transformed to sulfuric acid in the atmosphere. Through precipitation (i.e., acid rain), sulfuric acid can enter surface waters, lowering the pH and raising sulfate levels. III....

1994-12-20

129

Precipitation chemistry at Turrialba, Costa Rica  

SciTech Connect

Bulk precipitation samples were collected weekly at Turrialba, Costa Rica, from March 1979 through March 1981. The samples were analyzed for pH, conductivity, major cations and anions, nutrient N and P species and 12 trace metals. Precipitation was found to contain low levels of minerals, nutrients and acidity. During the spring period of low rainfall and increased agricultural activity, high levels of chemical constituents were observed. Low rainfall rates at this time resulted in relatively low depositions. The volume weighted pH over the 2 year period was 5.34 and ranged from 4.81 to 6.35. On the basis of equivalent ratios, excess sulfate was determined to be the principal acidic anion. Excess sulfate comprised 85% of the total sulfate and may result from long-range transport, biogenic emission, or sulfurous emission from nearby volcanic fumaroles. 27 references, 5 figures, 3 tables.

Hendry, C.D.; Berish, C.W.; Edgerton, E.S.

1984-11-01

130

Selective total encapsulation of the sulfate anion by neutral nano-jars.  

PubMed

Nano-sized toroidal copper(II)-hydroxide/pyrazolate assemblies, lined by H-bond donors on the inside and hydrophobic on the outside, selectively extract sulfate from mixtures with nitrate or perchlorate. Tetrabutylammonium "lids" seal the "nano-jars" and render the encapsulated sulfate anion completely buried and inaccessible, so that it is not precipitated by Ba(2+) ions. PMID:22669223

Fernando, Isurika R; Surmann, Stuart A; Urech, Alexander A; Poulsen, Alexander M; Mezei, Gellert

2012-07-11

131

Improved Spectrophotometric Analysis of Barium Styphnate.  

National Technical Information Service (NTIS)

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 bari...

J. A. Blasi, N. E. Brown

1983-01-01

132

Barium Additives As Diesel Smoke Suppressants  

Microsoft Academic Search

The body of information presented in this paper is directed to those individuals concerned with the emission of smoke from diesel engines. A series of tests was performed on a Petter Type AA1 diesel engine using barium smoke suppressant additives. An Andersen cascade type sampler was used to collect samples and thus study the effect of the additive upon the

C. David Turley; David L. Brenchley; Robert R. Landolt

1973-01-01

133

Observations on a Fully Ionized Barium Plasma  

Microsoft Academic Search

A series of spectroscopic measurements in a fully ionized barium plasma column is described and discussed. The plasma was generated in the Q-1 device in a manner similar to that used to make alkali-metal plasmas. The observations show that the density contours and the temperature profiles in the body of the plasma were strongly influenced by conditions at the end

N. Rynn; E. Hinnov; L. C. Johnson

1965-01-01

134

Quantum manipulation on the Barium quadrupolar transition  

E-print Network

and stabilization of a new fiber laser system to ma- nipulate the Barium quadrupolar transition, with the aim . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 3 Trapped ion coupled to a laser field 18 3.1 Light-matter interaction . . . . . . . . . . . . . . . 55 6 Spectroscopy and sideband cooling on a single 138 Ba+ 58 6.1 Quantum jumps using the fiber laser . . . . . . . . . . . . .

Blatt, Rainer

135

Strength and toughness of barium titanate ceramics  

Microsoft Academic Search

The effect of processing variables on the mechanical and electrical properties of holmium-doped barium titanate ceramics with a positive temperature coefficient of resistance has been investigated. This paper contains details of the tests used to measure the mechanical properties of ceramics prepared using four compositional mixes. Two methods of measuring strength were used: diametral compression of disc samples and four-point

J. M. Blamey; T. V. Parry

1993-01-01

136

Precipitation Matters  

ERIC Educational Resources Information Center

Although weather, including its role in the water cycle, is included in most elementary science programs, any further examination of raindrops and snowflakes is rare. Together rain and snow make up most of the precipitation that replenishes Earth's life-sustaining fresh water supply. When viewed individually, raindrops and snowflakes are quite…

McDuffie, Thomas

2007-01-01

137

Sulfate attack expansion mechanisms  

SciTech Connect

A specially constructed stress cell was used to measure the stress generated in thin-walled Portland cement mortar cylinders caused by external sulfate attack. The effects of sulfate concentration of the storage solution and C{sub 3}A content of the cement were studied. Changes in mineralogical composition and pore size distribution were investigated by X-ray diffraction and mercury intrusion porosimetry, respectively. Damage is due to the formation of ettringite in small pores (10–50 nm) which generates stresses up to 8 MPa exceeding the tensile strength of the binder matrix. Higher sulfate concentrations and C{sub 3}A contents result in higher stresses. The results can be understood in terms of the effect of crystal surface energy and size on supersaturation and crystal growth pressure.

Müllauer, Wolfram, E-mail: wolf_m@gmx.at; Beddoe, Robin E.; Heinz, Detlef

2013-10-15

138

The Use of Seaweed and Sugarcane Bagasse for the Biological Treatment of Metal-contaminated Waters Under Sulfate-reducing Conditions  

Microsoft Academic Search

When wetlands reach maximum treatment capacity to remove heavy metals, removal can still take place through precipitation as sulfide because of the biological reduction of sulfate. To achieve this goal, anaerobic conditions must be attained, a sulfate source must exist, and an adequate substrate for sulfate-reducing bacteria (SRB) is also required. In the present work, two ligneous-cellulosic materials, a brown

Márcia Monteiro Machado Gonçalves; Luiz Antonio Oliveira de Mello; Antonio Carlos Augusto da Costa

2008-01-01

139

Acidic precipitation  

SciTech Connect

At the International Symposium on Acidic Precipitation, over 400 papers were presented, and nearly 200 of them are included here. They provide an overview of the present state of the art of acid rain research. The Conference focused on atmospheric science (monitoring, source-receptor relationships), aquatic effects (marine eutrophication, lake acidification, impacts on plant and fish populations), and terrestrial effects (forest decline, soil acidification, etc.).

Martin, H.C.

1987-01-01

140

Measuring Precipitation  

NSDL National Science Digital Library

Students will design, build and then test a rain gauge to measure precipitation. By sharing their results, they will recognize the need for standardization and precision in scientific tools. All background information, student worksheets and images/photographs/data are included in these downloadable sections: Teacherâs Guide, Student Capture Sheet and PowerPoint Presentation. This activity uses the 5E instructional model and is part of the Survivor Earth series of one-hour lessons.

141

Precipitation Matters  

NSDL National Science Digital Library

Although weather, including its role in the water cycle, is included in most elementary science programs, any further examination of raindrops and snowflakes is rare. Together rain and snow make up most of the precipitation that replenishes Earth's life-sustaining fresh water supply. When viewed individually, raindrops and snowflakes are quite varied either in size or shape and provide surprising hints about the atmospheric conditions in which they formed.

Mcduffie, Thomas

2007-07-01

142

Precipitation Events: Probability of Precipitation Bias Statistics.  

National Technical Information Service (NTIS)

Bias statistics were generated for four big precipitation events which occurred between January 1 and February 10, 2008. Big events were defined to be periods when the National Precipitation Verification Unit (NPVU) precipitation analysis indicated that p...

D. Hazen

2008-01-01

143

Gaseous calcium, strontium, and barium phosphites  

Microsoft Academic Search

The authors investigated the composition of the vapor over calcium, strontium, and barium orthophosphates in the temperature range of 1900-2500°K. The study was carried out on an MS-1301 mass spectrometer; the vaporization was carried out from molybdenum Knudsen chambers. The heating was carried out by electron bombardment, and the temperature was measured with an EOP-66 optical pyrometer. The ions Me\\/sup

S. I. Lopatin; G. A. Semenov

1986-01-01

144

Prospects for Barium Tagging in Gaseous Xenon  

NASA Astrophysics Data System (ADS)

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.

Sinclair, D.; Rollin, E.; Smith, J.; Mommers, A.; Ackeran, N.; Aharmin, 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.; Gornea, G.; Graham, K.; Gratta, G.; Green, M.; Hagemann, C.; Hall, C.; Hall, K.; Hallman, D.; Hargrove, C.; Herrin, S.; Kaufman, L. K.; Leonard, D. S.; LePort, F.; Mackay, D.; MacLennan, R.; Mong, B.; Montero Díez, M.; Müller, A. R.; Neilson, R.; Niner, E.; Odian, A.; O'Sullivan, K.; Ouellet, C.; Piepke, A.; Pocar, A.; Prescott, C. Y.; Pushkin, K.; Rowson, P. C.; Slutsky, S.; Stekhanov, V.; Twelker, K.; Voskanian, N.; Vuilleumier, J.-L.; Wichoski, U.; Wodin, J.; Yang, L.; Yen, Y.-R.

2011-08-01

145

Aluminum Sulfate 18 Hydrate  

ERIC Educational Resources Information Center

A chemical laboratory information profile (CLIP) of the chemical, aluminum sulfate 18 hydrate, is presented. The profile lists physical and harmful properties, exposure limits, reactivity risks, and symptoms of major exposure for the benefit of teachers and students using the chemical in the laboratory.

Young, Jay A.

2004-01-01

146

PIMLUCK KIJJANAPANICH SULFATE REDUCTION  

E-print Network

Metals from Acid Mine Drainage 37 3.1 Introduction 38 3.2 Material and Methods 39 3.2.1 Acid mine drainage (AMD) 39 3.2.2 Sulfate reducing bacteria (SRB) inoculums 40 3.2.3 Organic substrates 40 3 Reduction in Gypsiferous Mine Soils from Nakhon Si Tham

Paris-Sud XI, Université de

147

Prolonged Intraocular Pressure Reduction Following Intravitreal Barium Injection in Rabbits  

Microsoft Academic Search

The isolated ciliary epithelium contains barium-inhibitable potassium channels. The present study was aimed at testing the in vivo effects of barium on aqueous humor dynamics in rabbits. BaCl2was administered to one eye by topical delivery or intravitreal injection. Dynamic measurements included intraocular pressure, outflow facility, episcleral venous pressure and aqueous flow (fluorophotometry). Barium dynamics were studied using133Ba. Intraocular pressure was

THEODORE KRUPIN; ABBAS HYDERI; DIANE KARALEKAS; MARK J. FRITZ

1996-01-01

148

Sulfates and phyllosilicates in Aureum Chaos, Mars  

NASA Astrophysics Data System (ADS)

Many Martian regions show a hydrated mineralogy indicating that aqueous processes played a major role in the planet's past. This study combines short wave infrared data, imagery and elevation data to identify these minerals in an equatorial chaotic terrain region and to find out their stratigraphy and geological context. Local Interior Layered Deposits (ILD) display three stratigraphic units: The lowest unit shows massive and also layered, monohydrated sulfate (MHS, best matching kieserite; 20-650 m thick), intercalated hydroxylated ferric sulfates (HFS, best matching jarosite) and ferric oxides. The overlying polyhydrated sulfate (PHS) is commonly layered (20-40 m thick), smooth to heavily fractured, partially with ferric oxides. Spectrally neutral, distinctly layered, bumpy cap rock (40-300 m thick) forms the top. Units are spectrally and morphologically similar to deposits of Aram Chaos (PHS, MHS, ferric oxides; texture of ILD and cap rock) and Juventae Chasma (HFS). Here, the phyllosilicate nontronite is found attributed to chaotic terrain as a light-toned fractured exposure but also within dark, smooth mantling. Coexisting sulfates and phyllosilicates demonstrate geochemical variations in the aqueous environment. Conversions between sulfates and iron oxides are considered, since we might be looking at alteration products instead of the parent rock material. Here, PHS occurs along mantling edges and flat surfaces of MHS without showing textural differences; making it a potential alteration product of MHS (e.g. due to surface exposure). Since the facies and timing of sulfate formation remain undefined, two different formation models are considered: contemporaneous ILD and PHS deposition with diagenetic sulfate conversion due to overburden (into MHS, iron oxides) later on; and groundwater evaporation. The first is less likely since a (sharp) PHS-MHS boundary is required that would indicate a diagenetic formation. The second is more consistent with our observations concerning the potential anhydrous cap rock. Groundwater would have penetrated into a pre-existing sulfate-free ILD whose permeability and porosity would have defined the rate of water absorption and sulfate precipitation that finally lead to its cementation. The surface ages of chaotic terrain (late Hesperian) and mantling deposits (mid to late Amazonian) further constrain the ILD age and potentially the emplacement of sulfates. We suggest that phyllosilicates in the mantling are allochthonous. In contrast, determining the deposition of in-situ phyllosilicates is theoretical; they could be Noachian (excavated material, following the 'phyllosian' era), or instead late Hesperian or even younger (syn- or post-chaotic). Alternatives, as known from Australian saline lakes, combine groundwater alteration with the observed mineralogy. There, close spatial and temporal associations of both mineral groups are explained by vertically separated geochemical environments (phyllosilicates in deep-, sulfates in shallow evaporitic facies). The preservation of nontronite, HFS and MHS displays that since their deposition a relatively dry environment with intermittent aqueous activity must have prevailed.

Sowe, M.; Wendt, L.; McGuire, P. C.; Neukum, G.

2012-12-01

149

Creating unstable velocity-space distributions with barium injections  

NASA Technical Reports Server (NTRS)

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.

Pongratz, M. B.

1983-01-01

150

Effects of barium concentration on oropharyngeal swallow timing measures.  

PubMed

Videofluoroscopy is commonly used for evaluating oropharyngeal swallowing but requires radiopaque contrast (typically barium). Prior studies suggest that some aspects of swallowing, including timing measures of oral and pharyngeal bolus transit, vary depending on barium concentration. The aim of our study was to identify timing differences in healthy swallowing between "thin" (40 % w/v concentration) and "ultrathin" (22 % w/v concentration) barium solutions. Twenty healthy adults (Ten women; mean age = 31 years) each performed a series of three noncued 5-ml swallows each of ultrathin and thin liquid barium solutions in videofluoroscopy. Timing measures were compared between barium concentrations using a mixed-model ANOVA. The measures of interest were stage transition duration, pharyngeal transit time, and duration of upper esophageal sphincter opening. Significant differences were observed in the timing measures of swallowing with respect to barium concentration. In all cases, longer durations were seen with the higher barium concentration. Barium concentration influences timing parameters in healthy swallowing, even between ultrathin and thin concentrations. Clinicians need to understand and control for the impact of different barium stimuli on swallowing physiology. PMID:24045851

Stokely, Shauna L; Molfenter, Sonja M; Steele, Catriona M

2014-02-01

151

Experimental study of acid-sulfate alteration of basalt and implications for sulfate deposits on Mars  

NASA Astrophysics Data System (ADS)

Acid-sulfate alteration of basalt by SO2-bearing volcanic vapors has been proposed as one possible origin for sulfate-rich deposits on Mars. To better define mineralogical signatures of acid-sulfate alteration, laboratory experiments were performed to investigate alteration pathways and geochemical processes during reaction of basalt with sulfuric acid. Pyroclastic cinders composed of phenocrysts including plagioclase, olivine, and augite embedded in glass were reacted with sulfuric acid at 145 °C for up to 137 days at a range of fluid : rock ratios. During the experiments, the phenocrysts reacted rapidly to form secondary products, while the glass was unreactive. Major products included amorphous silica, anhydrite, and Fe-rich natroalunite, along with minor iron oxides/oxyhydroxides (probably hematite) and trace levels of other sulfates. At the lowest fluid : rock ratio, hexahydrite and an unidentified Fe-silicate phase also occurred as major products. Reaction-path models indicated that formation of the products required both slow dissolution of glass and kinetic inhibitions to precipitation of a number of minerals including phyllosilicates and other aluminosilicates as well as Al- and Fe-oxides/oxyhydroxides. Similar models performed for Martian basalt compositions predict that the initial stages of acid-sulfate alteration of pyroclastic deposits on Mars should result in formation of amorphous silica, anhydrite, Fe-bearing natroalunite, and kieserite, along with relict basaltic glass. In addition, analysis of the experimental products indicates that Fe-bearing natroalunite produces a Mössbauer spectrum closely resembling that of jarosite, suggesting that it should be considered an alternative to the component in sulfate-rich bedrocks at Meridiani Planum that has previously been identified as jarosite.

McCollom, Thomas M.; Robbins, Mark; Moskowitz, Bruce; Berquó, Thelma S.; Jöns, Niels; Hynek, Brian M.

2013-04-01

152

Sulfate metabolism. I. Sulfate uptake and redistribution of acid rain sulfate by edible plants  

SciTech Connect

Sulfur is the major component of polluted air in industrialized societies. Atmospheric sulfur is converted to sulfuric acid through a series of chemical reactions which can eventually reenter many ecosystems. When edible plants are grown in soils containing varying amounts of sulfate, the roots take up and transport inorganic sulfate to the stems and leaves. The sulfate taken up by the roots and the amount transported to the stem and leaves was found to be a function of the concentration of sulfate in the soil. Inorganic sulfate taken up by a corn plant seedling can be rapidly converted to organic sulfate by the root system. Nine days after one of a pair of pea plants was inoculated with artificial acid rain sulfate (dilute H/sub 2//sup 35/SO/sub 4/) it was found that the sulfate was translocated not only in the inoculated plant, but also to the uninoculated pea plant in the same container. Also, when the leaves of a mature potato plant were inoculated with artificial acid rain sulfate it was found that the sulfate was translocated into the edible potatoes. Fractionation of the potatoes showed that most of the sulfate was water soluble of which 30% was inorganic sulfate and 70% was in the form of organic sulfur. One third of the non-water soluble translocated acid rain sulfate was equally divided between lipid and non-lipid organic sulfur of the potato. 9 references, 2 figures, 5 tables.

Dallam, R.D.

1987-03-23

153

Ferric sulfates on Mars: Surface Explorations and Laboratory Experiments  

NASA Astrophysics Data System (ADS)

Recent results from missions to Mars have reinforced the importance of sulfates for Mars science. They are the hosts of water, the sinks of acidity, and maybe the most active species in the past and current surface/near-surface processes on Mars. Fe-sulfate was found frequently by Spirit and Opportunity rovers: jarosite in Meridiani Planum outcrops and a less specific "ferric sulfate" in the salty soils excavated by Spirit at Gusev Crater. Pancam spectral analysis suggests a variety of ferric sulfates in these soils, i.e. ferricopiapite, jarosite, fibroferrite, and rhomboclase. A change in the Pancam spectral features occurred in Tyrone soils after ~ 190 sols of exposure to surface conditions. Dehydration of ferric sulfate is a possible cause. We synthesized eight ferric sulfates and conducted a series of hydration/dehydration experiments. Our goal was to establish the stability fields and phase transition pathways of these ferric sulfates. In our experiments, water activity, temperature, and starting structure are the variables. No redox state change was observed. Acidic, neutral, and basic salts were used. Ferric sulfate sample containers were placed into relative humidity buffer solutions that maintain static relative humidity levels at three temperatures. The five starting phases were ferricopiapite (Fe4.67(SO4)6(OH)2.20H2O), kornelite (Fe2(SO4)3.7H2O), rhomboclase (FeH(SO4)2.4H2O), pentahydrite (Fe2(SO4)3.5H2O), and an amorphous phase (Fe2(SO4)3.5H2O). A total of one hundred fifty experiments have been running for nearly ten months. Thousands of coupled Raman and gravimetric measurements were made at intermediate steps to monitor the phase transitions. The first order discovery from these experiments is the extremely large stability field of ferricopiapite. Ferricopiapite is the major ferric sulfate to precipitate from a Fe3+-S-rich aqueous solution at mid-low temperature, and it has the highest H2O/Fe ratio (~ 4.3). However, unlike the Mg-sulfate with highest hydration state (epsomite, at mid-low temperature), which would dehydrate readily at low relative humidity, ferricopiapite remains unchanged over ten months under extremely dry conditions. On the other hand, amorphous ferric sulfate which forms easily from solutions at dry conditions, is similar to the amorphous magnesium sulfate in stability field, thus can potentially be a very important phase in the phase transition pathways of ferric sulfates on Mars.

Wang, A.; Ling, Z.; Freeman, J. J.

2008-12-01

154

Calcium sulfate crystallization along citrus root channels in a Florida soil exhibiting acid sulfate properties  

SciTech Connect

The authors observed euhedral crystals in Manatee soil in a citrus grove in St. Lucie County, Florida. The material was identified as gypsum (CaSO/sub 4/ /times/ 2H/sub 2/O) using x-ray diffraction and infrared spectra. Photomicrography and scanning electron microscopy revealed that gypsum accumulated both in old root channels and within citrus root tissue of the Btg horizon. The subsurface horizons had elevated sulfate levels, a low initial pH, a drop (0.5 unit) in pH upon air-drying. Electrical conductivity paralleled the concentration of water-soluble sulfate. High levels of calcium and sulfate occurred for horizons above the water table. This accumulation is attributed to groundwater bearing these ions and subsequently discharging them to the overlying soil. Dead citrus roots appear to act as wicks to aid water transfer from lower to higher horizons. The roots and their empty channels provide spaces in which the gypsum can precipitate if the concentrations of calcium and sulfate in the evaporating groundwater exceed the solubility product of gypsum.

Syslo, S.K.; Myhre, D.L.; Harris, W.G.

1988-02-01

155

Mechanism of flocculation of sulfate lignin by polydimethyldiallylammonium chloride  

SciTech Connect

This paper investigates the influence of the molecular weight of the cationic flocculant polydimethyldiallylammonium chloride (PC), which has a high positive charge density, on the flocculation efficiency, electrokinetic behavior, and kinetics of precipitation of sulfate lignin (SL) over a wide range of pH. Studies have been performed in the adsorption of PC on the SL particles, as influenced by the molecular weight of the flocculant. The studies were performed with the airm of finding the optimal conditins for utilization of PC in the process of decolorizing caustic-containing wastewater from sulfate pulp and paper production, the color of which is 90% due to the presence of SL.

Chernoberezhskii, A.Yu.; Semenov, V.P.

1986-04-10

156

Sulfation of chondroitin. Specificity, degree of sulfation, and detergent effects with 4-sulfating and 6-sulfating microsomal systems  

SciTech Connect

Microsomal preparations from chondroitin 6-sulfate-producing chick embryo epiphyseal cartilage, and from chondroitin 4-sulfate-producing mouse mastocytoma cells, were incubated with UDP-(14C)glucuronic acid and UDP-N-acetylgalactosamine to form non-sulfated proteo(14C)chondroitin. Aliquots of the incubations were then incubated with 3'-phosphoadenylylphosphosulfate (PAPS) in the presence or absence of various detergents. In the absence of detergents, there was good sulfation of this endogenous proteo(14C)chondroitin by the original microsomes from both sources. Detergents, with the exception of Triton X-100, markedly inhibited sulfation in the mast cell system but not in the chick cartilage system. These results indicate that sulfation and polymerization are closely linked on cell membranes and that in some cases this organization can be disrupted by detergents. When aliquots of the original incubation were heat inactivated, and then reincubated with new microsomes from chick cartilage and/or mouse mastocytoma cells plus PAPS, there was no significant sulfation of this exogenous proteo(14C) chondroitin with either system unless Triton X-100 was added. Sulfation of exogenous chondroitin and chondroitin hexasaccharide was compared with sulfation of endogenous and exogenous proteo(14C)chondroitin. Sulfate incorporation into hexasaccharide and chondroitin decreased as their concentrations (based on uronic acid) approached that of the proteo(14C)chondroitin. At the same time, the degree of sulfation in percent of substituted hexosamine increased. However, the degree of sulfation did not reach that of the endogenous proteo(14C)chondroitin. Hexasaccharide and chondroitin sulfation were stimulated by the presence of Triton X-100. However, in contrast to the exogenous proteo(14C)chondroitin, there was some sulfation of hexasaccharide and chondroitin in the absence of this detergent.

Sugumaran, G.; Silbert, J.E.

1988-04-05

157

Migration and escape of barium atoms in a thermionic cathode  

Microsoft Academic Search

A quantitative study of the physical processes on a thermionic cathode that are crucial to both cathode life and noise are investigated. Of particular interest are the transport of the barium atoms from the cathode interior to the cathode surface and beyond. To investigate these physical processes, a model of barium migration to the surface and its subsequent removal by

Kevin L. Jensen; Y. Y. Lau; B. Levush

2000-01-01

158

PHOTOSENSITIVE CENTERS AND CHARGE TRANSFER PROCESSES IN BARIUM CALCIUM TITANATE  

E-print Network

PHOTOSENSITIVE CENTERS AND CHARGE TRANSFER PROCESSES IN BARIUM CALCIUM TITANATE G.MALOVICHKO, V calcium titanate crystals, Ba0.77Ca0.23TiO3, in the temperature range between 4.2 K and 300 K are reported of crystals from barium titanate (BT) family make them promising candidates for various applications

Malovichko, Galina

159

Barium Tagging for the Enriched Xenon Observatory (EXO)  

NASA Astrophysics Data System (ADS)

The EXO experiment is designed to search for zero-neutrino double beta decay of the isotope Xe^136, in order to better understand the nature of neutrinos. Since the daughter of this decay is barium (Ba^136), detecting the presence of Ba^136 at a decay site (called ``barium tagging'') is the best way to reject backgrounds in the search for this decay. It is hopeful that barium tagging will be implemented in the next phase of EXO. One proposed barium tagging method is to trap the barium ion in a solid xenon matrix (by freezing the liquid xenon surrounding the decay), and move it to another location to do laser-induced fluorescence spectroscopy counting. Our group at CSU is researching the detection of single barium ions and atoms within a solid xenon matrix. A barium ion beam is used to implant the ions into freezing xenon, where laser spectroscopy is then performed. We demonstrate successful detection of very small numbers, and are nearing single-barium detection.

Walton, Timothy

2012-10-01

160

Cardiotoxic and bronchoconstrictor effects of industrial metal fumes containing barium.  

PubMed

For certain metal arc-welding and other metal processing operations, compounds of barium are used as flux components. Airborne fumes generated by welding with electrodes using barium fluoride or carbonate fluxes may contain 15-30% of barium in readily water-soluble form (Dare et al. 1984). Urine of welders inhaling such fumes was shown to contain elevated levels of barium ions (up to 234 micrograms/l). To assess the possible hazards of such exposure, the toxic potencies of fume samples, expressed in terms of their water-soluble barium ion contents, were compared with effects of solutions of barium salts in anaesthetised guinea-pigs. Dose-effect relationships were established and it was verified that acute toxic effects of inhaled aerosols or of intravenous bolus administration correlated with the barium contents of various forms of welding fumes. Bronchopulmonary reactivity to the barium was observed as marked increases in resistance to ventilatory air-flow, indicating bronchoconstriction. Simultaneously, marked pressor effects on blood pressure occurred. ECG abnormalities indicated myocardial hyperexcitability. Effects were modified by nifedipine and propranolol pretreatments. PMID:3468925

Hicks, R; Caldas, L Q; Dare, P R; Hewitt, P J

1986-01-01

161

Experiments with remote entanglement using single barium ions Nathan Kurz  

E-print Network

Experiments with remote entanglement using single barium ions Nathan Kurz A dissertation submitted This is to certify that I have examined this copy of a doctoral dissertation by Nathan Kurz and have found entanglement using single barium ions Nathan Kurz Chair of the Supervisory Committee: Dr. Boris B. Blinov

Blinov, Boris

162

Barium strontium titanate powder obtained by polymeric precursor method  

SciTech Connect

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.

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

2003-03-15

163

Preparation of dye waste-barium sulfate hybrid adsorbent and application in organic wastewater treatment.  

PubMed

A new hybrid material was developed by the template-free hybridization of weak acidic pink red B (APRB, C.I. 18073) with BaSO(4). The composition and structure of the material were determined and characterized. In contrast to conventional sorbents, the hybrid material has a specific surface area of 0.89 m(2)/g, but it contains lots of negative charges and lipophilic groups as the basis of specific adsorption. The efficient removal of cationic dyes and persistent organic pollutants (POPs) indicates that it has an improved adsorption capacity and selectivity with a short removal time less than 2 min; while the hybrid sorbents fit the Langmuir isotherm model, and follow the octanol-water partition law. Instead of using APRB reagent, an APRB-producing wastewater was reused to prepare the cost-effective sorbent, and the equilibrium adsorption capacities of which reached 222 and 160 mg/g for EV and BPR, respectively. The sorbents was then used to treat three wastewater samples with satisfactory results of over 97% decolonization and 88% COD-decreasing. In addition, the hybrid sorbent was regenerated from sludge over five cycles, and its adsorption capacity was not appreciably changed. This work has developed a simple and eco-friendly method for synthesizing a practical and efficient sorbent. PMID:19850409

Hu, Zhang-Jun; Xiao, Yan; Zhao, Dan-Hua; Shen, Yu-Lin; Gao, Hong-Wen

2010-03-15

164

Current-voltage characteristics of barium polymethacrylate  

SciTech Connect

In this paper current-voltage characteristics of Barium Polymethacrylate (BaPMA) in the form of Al-BaPMA-Al structures are studied. The currents are measured in the voltage range 10 V-1 kV. At low voltages an ohmic relation is observed and at higher voltages the Poole-Frenkel mechanism is proposed. The mechanism of conduction has been explained on the basis of different current-voltage and current-temperature curves. The activation energy values calculated using Arrhenius relation fall in the range 0.25-2 eV, suggesting a sequence of trapping levels.

Chohan, M.H. (Lab. for Electrical Characterization of Polymers, Dept. of Electronics, Quaid-i-Azam Univ., Islamabad (PK)); Zulfiqar, M.; Sapra, Z.H.; Husain, R.; Zulfiqar, S. (Dept. of Chemistry, Quaid-i-Azam Univ., Islamabad (PK))

1992-06-30

165

Barium dierbium(III) tetra-sulfide.  

PubMed

Barium dierbium(III) tetra-sulfide, BaEr2S4, crystallizes with four formula units in the ortho-rhom-bic space group Pnma in the CaFe2O4 structure type. The asymmetric unit contains two Er, one Ba, and four S atoms, each with .m. site symmetry. The structure consists of channels formed by corner- and edge-sharing ErS6 octa-hedra in which Ba atoms reside. The resultant coordination of Ba is that of a bicapped trigonal prism. PMID:23476480

Mesbah, Adel; Stojko, Wojciech; Ibers, James A

2013-03-01

166

Barium dierbium(III) tetra-sulfide  

PubMed Central

Barium dierbium(III) tetra­sulfide, BaEr2S4, crystallizes with four formula units in the ortho­rhom­bic space group Pnma in the CaFe2O4 structure type. The asymmetric unit contains two Er, one Ba, and four S atoms, each with .m. site symmetry. The structure consists of channels formed by corner- and edge-sharing ErS6 octa­hedra in which Ba atoms reside. The resultant coordination of Ba is that of a bicapped trigonal prism. PMID:23476480

Mesbah, Adel; Stojko, Wojciech; Ibers, James. A

2013-01-01

167

Europium-doped barium bromide iodide  

SciTech Connect

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.

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

2009-10-21

168

Dielectric properties of barium titanate supramolecular nanocomposites.  

PubMed

Nanostructured dielectric composites can be obtained by dispersing high permittivity fillers, barium titanate (BTO) nanocubes, within a supramolecular framework. Thin films of BTO supramolecular nanocomposites exhibit a dielectric permittivity (?r) as high as 15 and a relatively low dielectric loss of ?0.1 at 1 kHz. These results demonstrate a new route to control the dispersion of high permittivity fillers toward high permittivity dielectric nanocomposites with low loss. Furthermore, the present study shows that the size distribution of nanofillers plays a key role in their spatial distribution and local ordering and alignment within supramolecular nanostructures. PMID:24584569

Lee, Keun Hyung; Kao, Joseph; Parizi, Saman Salemizadeh; Caruntu, Gabriel; Xu, Ting

2014-04-01

169

Production of translationally cold barium monohalide ions  

NASA Astrophysics Data System (ADS)

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.

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

2013-08-01

170

Short-cavity squeezing in barium  

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

171

Evaluation of barium hydroxide treatment efficacy on a dolomitic marble.  

PubMed

The Arch of Peace, by Luigi Cagnola, is one of the most famous neoclassical monuments in Milan. It has been subjected to conservative intervention in 1998. In the present paper the efficacy of the consolidation by means of barium hydroxide has been evaluated. The stone material showed severe degradation phenomena as: erosion, pulverisation, exfoliation. The analytical data acquired through X-ray diffraction (XRD), infrared spectrophotometry (FTIR) and scanning electron microscopy (SEM-EDX), allowed to compare the conditions of stone before and after the treatment with barium hydroxide. The presence of barium has been put in evidence mainly on the surface as barium sulphate, whereas barium is only sporadically present within the thickness of the decayed material. The treatment was judged not satisfying and its inefficacy is, most probably, due to a not suitable cleaning procedure carried out before the consolidation. PMID:11836959

Toniolo, L; Colombo, C; Realini, M; Peraio, A; Positano, M

2001-01-01

172

Does peppermint oil relieve spasm during barium enema?  

PubMed

The effectiveness of topical peppermint oil added to barium sulphate suspension in relieving colonic muscle spasm during double contrast barium enema examination was assessed in a double blind study. 141 patients were randomized either to a control group (71 patients) examined with standard barium suspension or to the treatment group which received peppermint oil mixed with the barium preparation. No residual spasm was evident in a significant proportion of patients in the treated group (60%) compared with the control group (35%) (p < 0.001). The patients' acceptability of the procedure was good and there were no adverse effects on the overall quality of the examination. In conclusion, the addition of peppermint oil to the barium suspension seems to reduce the incidence of colonic spasm during the examination. The technique is simple, safe, cheap and it may lessen the need for intravenous administration of spasmolytic agents. PMID:7551780

Sparks, M J; O'Sullivan, P; Herrington, A A; Morcos, S K

1995-08-01

173

Indirect determination of cyclamate by an on-line continuous precipitation-dissolution flow system  

Microsoft Academic Search

A continuous-flow procedure is proposed for the indirect determination of sodium cyclamate by an atomic absorption spectrometric method in artificial sweeteners mixtures and soft drinks. Sulfamic group is oxidized to sulfate and it is continuously precipited with lead ion in a flow manifold. The lead sulfate formed is retained on a filter, washed with diluted ethanol and dissolved in ammonium

M. C Yebra; P Bermejo

1998-01-01

174

Remediation of acid mine drainage with sulfate reducing bacteria  

SciTech Connect

Sulfate reducing bacteria have been shown to be effective at treating acid mine drainage through sulfide production and subsequent precipitation of metal sulfides. In this laboratory experiment for undergraduate environmental chemistry courses, students design and implement a set of bioreactors to remediate acid mine drainage and explain observed changes in dissolved metal concentrations and pH. Using synthetic acid mine drainage and combinations of inputs, students monitor their bioreactors for decreases in dissolved copper and iron concentrations.

Hauri, J.F.; Schaider, L.A. [Assumption College, Worcester, MA (USA)

2009-02-15

175

Sulfate in acid rain data - do the patterns make sense?  

SciTech Connect

A high quality national record of precipitation chemistry is being collected through the operation of the National Atmospheric Deposition Program/National Trends Network (NADP/NTN). This network began in 1978 with less than 20 sites and by the mid 1980`s had grown to about 200 sites which is about the number of sites currently in operation. Lynch et al. have been reporting time trend results for this data, with their most recent analysis showing that sulfate in NADP/NTN decreased dramatically in 1995 which agrees with the substantial decrease in sulfur dioxide emissions. The various network data available before NADP/NTN have been reported to have a variety of problems, especially related to the effect on pH of the elevated levels of base cations. The sulfate and nitrate data may be more useable. This paper reassesses the sulfate data available from the Junge network to see if these data can be used to extend the comparison of sulfate in precipitation and sulfur dioxide emissions back to the mid 1950`s.

Stensland, G.J. [Illinois State Water Survey, Champaign, IL (United States)

1997-12-31

176

Electrodeposition of titania and barium titanate thin films for high dielectric applications  

NASA Astrophysics Data System (ADS)

In order to address the requirement of a low-temperature low-cost cost processing for depositing high dielectric constant ceramic films for applications in embedded capacitor and flexible electronics technology, two different chemical bath processes, namely, thermohydrolytic deposition (TD) and cathodic electrodeposition (ED) have been exploited to generate titania thin films. In thermohydrolytic deposition technique, titania films were generated from acidic aqueous solution of titanium chloride on F: SnO2 coated glass and Si substrates by temperature assisted hydrolysis mechanism. On the other hand, in cathodic electrodeposition, in-situ electro-generation of hydroxyl ions triggered a fast deposition of titania on conductive substrates such as copper and F: SnO2 coated glass from peroxotitanium solution at low temperatures (˜0°C). In both techniques, solution compositions affected the morphology and crystallinity of the films. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques have been employed to perform such characterization. As both processes utilized water as solvent, the as-deposited films contained hydroxyl ligand or physically adsorbed water molecules in the titania layer. Besides that, electrodeposited films contained peroxotitanium bonds which were characterized by FTIR studies. Although as-electrodeposited titania films were X-ray amorphous, considerable crystallinity could be generated by heat treatment. The films obtained from both the processes showed v moderately high dielectric constant (ranging from 9-30 at 100 kHz) and high breakdown voltage (0.09-0.15 MV/cm) in electrical measurements. To further improve the dielectric constant, electrodeposited titania films were converted to barium titanate films in high pH barium ion containing solution at 80-90°C. The resultant film contained cubic crystalline barium titanate verified by XRD analysis. Simple low-temperature hydrothermal technique of conversion worked perfect for F:SnO2 coated glass substrates, but in this process, high pH precursor caused corrosion in copper substrates and deposition of copper oxide in the final films. To overcome this, an innovative technique, which incorporates an electrochemical protection of substrates by application of cathodic potential in addition to common hydrothermal conversion, has been adopted. Films generated by common hydrothermal technique on F:SnO 2/glass substrates and via electrochemical-hydrothermal technique on Cu substrates showed promising dielectric behavior. Apart from the experimental studies, this report also includes various thermodynamic studies related to hydrolysis and precipitation of titanium ion, protection of copper during titania deposition and barium titanate conversion. Gibbs free energy based model and speciation studies were used to understand supersaturation which is a controlling factor in thermohydrolytic deposition. Similar approaches were utilized to understand the possibilities of barium titanate formation at different Ba2+ concentrations with different pH conditions. Possibilities of atmospheric carbon dioxide incorporation to generate barium carbonate instead of barium titanate formation were also determined by mathematical calculations. Whenever relevant, results of such theoretical analysis were utilized to design the experiment or to explain the experimental observations.

Roy, Biplab Kumar

177

Effects on aqueous barium titanate tape properties of passivation of barium ion leaching by using dispersants  

Microsoft Academic Search

To passivate a barium titanate (BaTiO3) ceramic powder surface from Ba2+ ion leaching in water, passivation agent layer (PAL) was formed by drying the slurry after adding a commercial polymeric dispersant. By following the several characteristic steps of actual MLCC production process, slip and green properties were compared for two different polymer-adding modes; one is the PAL and the other

Dang-Hyok Yoon; Burtrand I. Lee

2004-01-01

178

Designed microstructures in textured barium hexaferrite  

NASA Astrophysics Data System (ADS)

It is a fundamental principle of materials science that the microstructure of a material defines its properties and ultimately its performance for a given application. A prime example of this can be found in the large conch shell Strombus gigas, which has an intricate microstructure extending across five distinct length scales. This microstructure gives extraordinary damage tolerance to the shell. The structure of Strombus gigas cannot be replicated in a modern engineering ceramic with any existing processing technique, so new processing techniques must be developed to apply this structure to a model material. Barium hexaferrite was chosen as a model material to create microstructures reminiscent of Strombus gigas and evaluate its structure-property relations. This work describes novel processing methods to produce textured barium hexaferrite with no coupling between the sample geometry and the texture direction. This technique, combining magnetic field-assisted gelcasting with templated grain growth, also allows multilayer samples to be fabricated with different texture directions in adjacent layers. The effects of adding either B2O3 or excess BaCO 3 on the densification and grain growth of barium hexaferrite was studied. The texture produced using this technique was assessed using orientation imaging microscopy (OIM) at Oak Ridge National Laboratory. These measurements showed peak textures as high as 60 MRD and sharp interfaces between layers cast with different texture directions. The effect of oxygen on the quality of gelcasting is also discussed, and it is shown that with proper mold design, it is possible to gelcast multiple layers with differing texture directions without delamination. Monolithic and multilayer samples were produced and tested in four point bending to measure the strength and work of fracture. Modulus measurements, made with the ultrasonic pulse-echo technique, show clear signs of microcracking in both the isotropic and textured samples. Both the strength and work of fracture were shown to be affected by the texture direction. The multilayer samples did not show significant improvements in either strength or work of fracture, but they did show much less variability than the monolithic samples.

Hovis, David Brian

179

21 CFR 524.1484e - Neomycin sulfate and polymyxin B sulfate ophthalmic solution.  

Code of Federal Regulations, 2011 CFR

...false Neomycin sulfate and polymyxin B sulfate ophthalmic solution. 524.1484e Section 524.1484e Food and Drugs ...1484e Neomycin sulfate and polymyxin B sulfate ophthalmic solution. (a) Specifications. Each milliliter of the...

2011-04-01

180

Migration and redistribution of oxygen vacancy in barium titanate ceramics  

NASA Astrophysics Data System (ADS)

Degradation of barium titanate based multilayer capacitor mainly results from migration and redistribution of oxygen vacancy. For barium titanate ceramics, the authors observe an internal friction relaxation peak around 70°C due to oxygen vacancy, and its relaxation strength differs greatly for specimen aged at 85°C for 120h and at 150°C for 5h. Two possible explanations are proposed, one based on symmetry-conforming short-range order while the other on the interaction between oxygen vacancy and domain wall during aging process. In any case, relaxation thermodynamics is a powerful tool to investigate the migration and redistribution of oxygen vacancy in barium titanate ceramics.

Chen, L.; Xiong, X. M.; Meng, H.; Lv, P.; Zhang, J. X.

2006-08-01

181

Migration and redistribution of oxygen vacancy in barium titanate ceramics  

SciTech Connect

Degradation of barium titanate based multilayer capacitor mainly results from migration and redistribution of oxygen vacancy. For barium titanate ceramics, the authors observe an internal friction relaxation peak around 70 deg. C due to oxygen vacancy, and its relaxation strength differs greatly for specimen aged at 85 deg. C for 120 h and at 150 deg. C for 5 h. Two possible explanations are proposed, one based on symmetry-conforming short-range order while the other on the interaction between oxygen vacancy and domain wall during aging process. In any case, relaxation thermodynamics is a powerful tool to investigate the migration and redistribution of oxygen vacancy in barium titanate ceramics.

Chen, L.; Xiong, X. M.; Meng, H.; Lv, P.; Zhang, J. X. [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-Sen University, Guangzhou 510275 (China)

2006-08-14

182

A high-altitude barium radial injection experiment  

NASA Technical Reports Server (NTRS)

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.

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

183

Sulfur isotopes in sulfate in the inputs and outputs of a Canadian Shield watershed  

Microsoft Academic Search

The isotopic composition of sulfur in sulfate from precipitation, stream inflows and outflow of the Lake 239 watershed at the Experimental Lakes Area, northwestern Ontario, was monitored for four years, 1982–1985. Rainfall had ?34S of 3–9and a three year mean value weighted by the mass of sulfate of 4.8‰ Sulfur in streams ranged from 5–15 and displayed a pronounced seasonal

R. H. Hesslein; M. J. Capel; D. E. Fox

1988-01-01

184

Natural or anthropogenic? On the origin of atmospheric sulfate deposition in the Andes of southeastern Ecuador  

NASA Astrophysics Data System (ADS)

Atmospheric sulfur deposition above certain limits can represent a threat to tropical forests, causing nutrient imbalances and mobilizing toxic elements that impact biodiversity and forest productivity. Atmospheric sources of sulfur deposited by precipitation have being roughly identified in only a few lowland tropical forests. Even scarcer are these type of studies in tropical mountain forests, many of them megadiversity hotspots and especially vulnerable to acidic deposition. Here, the topographic complexity and related streamflow condition the origin, type, and intensity of deposition. Furthermore, in regions with a variety of natural and anthropogenic sulfur sources, like active volcanoes and biomass-burning, no source-emission data has been used for determining the contribution of each of them to the deposition. The main goal of the current study is to evaluate sulfate (SO4-) deposition by rain and occult precipitation at two topographic locations in a tropical mountain forest of southern Ecuador, and to trace back the deposition to possible emission sources applying back trajectory modeling. To link upwind natural (volcanic) and anthropogenic (urban/industrial and biomass-burning) sulfur emissions and observed sulfate deposition, we employed state of the art inventory and satellite data, including volcanic passive degassing as well. We conclude that biomass-burning sources generally dominate sulfate deposition at the evaluated sites. Minor sulfate transport occurs during the shifting of the predominant winds to the north and west. Occult precipitation sulfate deposition and likely rain sulfate deposition are mainly linked to biomass-burning emissions from the Amazon lowlands. Volcanic and anthropogenic emissions from the north and west contribute to occult precipitation sulfate deposition at the mountain crest Cerro del Consuelo meteorological station and to rain-deposited sulfate at the upriver mountain-pass El Tiro meteorological station.

Makowski Giannoni, S.; Rollenbeck, R.; Trachte, K.; Bendix, J.

2014-05-01

185

Natural or anthropogenic? On the origin of atmospheric sulfate deposition in the Andes of southeastern Ecuador  

NASA Astrophysics Data System (ADS)

Atmospheric sulfur deposition above certain limits can represent a threat to tropical forests, causing nutrient imbalances and mobilizing toxic elements that impact biodiversity and forest productivity. Atmospheric sources of sulfur deposited by precipitation have been roughly identified in only a few lowland tropical forests. Even scarcer are studies of this type in tropical mountain forests, many of them mega-diversity hotspots and especially vulnerable to acidic deposition. In these places, the topographic complexity and related streamflow conditions affect the origin, type, and intensity of deposition. Furthermore, in regions with a variety of natural and anthropogenic sulfur sources, like active volcanoes and biomass burning, no source emission data has been used for determining the contribution of each source to the deposition. The main goal of the current study is to evaluate sulfate (SO4- deposition by rain and occult precipitation at two topographic locations in a tropical mountain forest of southern Ecuador, and to trace back the deposition to possible emission sources applying back-trajectory modeling. To link upwind natural (volcanic) and anthropogenic (urban/industrial and biomass-burning) sulfur emissions and observed sulfate deposition, we employed state-of-the-art inventory and satellite data, including volcanic passive degassing as well. We conclude that biomass-burning sources generally dominate sulfate deposition at the evaluated sites. Minor sulfate transport occurs during the shifting of the predominant winds to the north and west. Occult precipitation sulfate deposition and likely rain sulfate deposition are mainly linked to biomass-burning emissions from the Amazon lowlands. Volcanic and anthropogenic emissions from the north and west contribute to occult precipitation sulfate deposition at the mountain crest Cerro del Consuelo meteorological station and to rain-deposited sulfate at the upriver mountain pass El Tiro meteorological station.

Makowski Giannoni, S.; Rollenbeck, R.; Trachte, K.; Bendix, J.

2014-10-01

186

Physico-chemical and in vitro biological study of zinc-doped calcium sulfate bone substitute.  

PubMed

In the present study, series of Zn incorporated calcium sulfate bone cements, with different amounts of doped Zn(0, 0.74, 1.97, 3.05, 4.21 wt %) were prepared by mixing a calcium sulfate hemihydrate powder and solutions of zinc sulfate, and the effect of zinc-doping on some physical, physico-chemical, and biological properties of the cements were investigated. Pure calcium sulfate cement was also made as control, with the mentioned powder and distilled water as liquid phase. The initial setting time and compressive strength of the cement significantly changed from 17 min and 3.2 MPa for the pure calcium sulfate to 6 min and 6 MPa for the Zn-added calcium sulfate, respectively. Compared to pure calcium sulfate, more gypsum precipitates were formed in the zinc sulfate added samples with a morphology of thin, elongated, and rod-shaped crystals. The biological properties of the samples were analyzed in the terms of cell viability and cell activity on human osteosarcoma (G-292) using MTT assay and alkaline phosphatase (ALP) activity in the cell culture medium. The best increased cell density and ALP activity were achieved for the calcium sulfate cement with a content of 0.74 wt % Zn, whereas a toxic behavior was observed for the samples with Zn concentrations more than 1.97%. PMID:19358260

Hesaraki, Saeed; Nemati, Roghayeh; Nazarian, Hamid

2009-10-01

187

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

PubMed Central

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

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

2014-01-01

188

Molecular Structure of Sulfate ion  

NSDL National Science Digital Library

Sulfate is a naturally occurring substance that is found in minerals and rocks, and in soil it is one of the most predominant anions. This substance results from the oxidation of elemental sulfur, sulfides, or organic sulfur. While sulfate is one of the least toxic anions, it is monitored under the Safe Drinking Water Act (SDWA). The anion is used in mining, pulping, metal and plating industries, water and sewage treatment, leather processing and in the manufacture of numerous chemicals, dyes, glass, soaps, textiles, fungicides, insecticides, astringents, and emetics. Various sulfate salts are used in foods, the estimated daily intake of sulfate from the consumption of food is approximately 453 milligrams (mg). Sulfate can have a cathartic effect on humans which results in the purgation of the alimentary canal, when 1000-2000 mg is ingested.

2002-09-11

189

Activated sludge as substrate for sulfate-reducing bacteria in acid mine drainage treatment  

SciTech Connect

Acid mine drainage (AMD), characterized by high concentrations of sulfates and heavy metals and low pH, presents a potential hazard to the environment.Several treatment processes (chemical precipitation, ion exchange, reverse osmosis, electrodialysis and electrolytic recovery) are available, but these are often too expensive. Biological treatment of AMD, mediated by sulfate-reducing bacteria (SRB), seems promising. The objective of this study was to use activated sludge as a carbon source for the SRB and determine the most effective COD/sulfate ratio and hydraulic retention time (HRT) for reducing sulfate. Such information would be useful for the application of the proposed two-stage system to AMD treatment. Since the aim of this study was to obtain sulfate reduction and to avoid methane production, it was decided to operate the digesters initially at low COD/SO{sub 4}{sup 2{minus}} ratios of 1.0, 1.5, and 2.0.

Al-Ani, W.A.G.; Henry, J.G.; Prasad, D. [Univ. of Toronto, Ontario (Canada)

1996-11-01

190

Study of the photovoltaic effect in thin film barium titanate  

NASA Technical Reports Server (NTRS)

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.

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

1983-01-01

191

Calculated emission rates for barium releases in space  

NASA Technical Reports Server (NTRS)

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.

Stenbaek-Nielsen, H. C.

1989-01-01

192

Characterization of Jarosite Formed upon Bacterial Oxidation of Ferrous Sulfate in a Packed-Bed Reactor †  

PubMed Central

A packed-bed bioreactor with activated-carbon particles as a carrier matrix material inoculated with Thiobacillus ferrooxidans was operated at a pH of 1.35 to 1.5 to convert ferrous sulfate to ferric sulfate. Despite the low operating pH, trace amounts of precipitates were produced in both the reactor and the oxidized effluent. X-ray diffraction and chemical analyses indicated that the precipitates were well-ordered potassium jarosite. The chemical analyses also revealed a relative deficiency of Fe and an excess of S in the reactor sample compared with the theoretical composition of potassium jarosite. Images PMID:16347799

Grishin, Sergei I.; Bigham, Jerry M.; Tuovinen, Olli H.

1988-01-01

193

Determination of trace elements in triglycine sulfate solutions  

NASA Technical Reports Server (NTRS)

Ten elements were divided into 2 groups. The elements in the first group included iron, nickel, chromium, manganese, copper, and gold. The elements in the second group included zinc, cobalt, lead, cadmium, and gold. Five ppm of each element in each group was spiked in a 1 percent triglycine sulfate (TGS) solution. Glycine was removed with 1-naphthyl isocyanate in ether medium. The glycine derivative 1-naphthyl isocyanate glycine was removed by filtration, and the filtrates were analyzed for the different elements. Analysis of these elements was performed by using the 5100 Perkin-Elmer Atomic Absorption Spectrophotometer. The result of these experiments was the observation that there was a decrease in the concentration of chromium and gold, which was interpreted to be due to the chelation of these elements by the derivative 1-naphthyl isocyanate glycine. Further research is needed to determine the concentration of other elements in triglycine sulfate (TGS) solutions. These elements will include lithium, sodium, rubidium, magnesium, calcium, strontium, barium, aluminum, and silicon. These are the most likely elements to be found in the sulfuric acid used in manufacturing the TGS crystal. Moreover, we will extend our research to investigate the structural formula of the violet colored chelated compounds, which had been formed by interaction of the derivative 1-naphthyl isocyanate glycine with the different elements, such as gold, chromium.

Tadros, Shawky H.

1993-01-01

194

Solar eclipse sign of intussusception on barium enema.  

PubMed

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. PMID:11793074

Raveenthiran, V

2002-01-01

195

Thermal expansion of nitrates of lead, barium and strontium  

Microsoft Academic Search

The expansion coefficients of barium, strontium and lead nitrates have been studied above room temperatures. Lead nitrate\\u000a decomposes rapidly beyond 200° C. while crystals of barium nitrate crack above 270° C. Strontium nitrate exhibited no such\\u000a phenomena till 550° C.\\u000a \\u000a These crystals are isomorphous. The expansion coefficients of lead and strontium nitrates are nearly equal; they also possess\\u000a the same

R. Srinivasan

1955-01-01

196

'Skidding' of the CRRES G-9 barium release  

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

197

Ion Exchange Studies for Removal of Sulfate from Hanford Tank Waste Envelope C (241-AN-107) Using SuperLig 655 Resin  

SciTech Connect

BNFL Inc. is evaluating various pretreatment technologies to mitigate the impacts of sulfate on the LAW vitrification system. One pretreatment technology for separating sulfate from LAW solutions involves the use of SuperLig{reg_sign} 655 (SL-655), a proprietary ion exchange material developed and supplied by IBC Advanced Technologies, Inc., American Fork, UT. This report describes testing of SL-655 with diluted ([Na] {approximately} 5 M) waste from Hanford Tank 241-AN-107 at Battelle, Pacific Northwest Division. Batch contact studies were conducted from 4 to 96 hours to determine the sulfate distribution coefficient and reaction kinetics. A small-scale ion exchange column test was conducted to evaluate sulfate removal, loading, breakthrough, and elution from the SL-655. In all of these tests, an archived 241-AN-107 tank waste sample (pretreated to remove Cs, Sr, and transuranics elements) was used. The experimental details and results are described in this report. Under the test conditions, SL-655 was found to have no significant ion exchange affinity for sulfate in this matrix. The batch contact study resulted in no measurable difference in the aqueous sulfate concentration following resin contact (K{sub d} {approximately} 0). The column test also demonstrated SL-655 had no practical affinity for sulfate in the tested matrix. Within experimental error, the sulfate concentration in the column effluent was equal to the concentration in the feed after passing 3 bed volumes of sample through the columns. Furthermore, some, if not all, of the decreased sulfate concentration in these first three column volumes of effluent can be ascribed to mixing and dilution of the 241-AN-107 feed with the interstitial liquid present in the column at the start of the loading cycle. Finally, ICP-AES measurements on the eluate solutions showed the presence of barium as soon as contact with the feed solution is completed. Barium is a metal not detected in the feed solution. Should the loss of barium be correlated with the resin's ability to selectively complex sulfate, then maintaining even the current limited resin characteristics for sulfate complexation over multiple cycles becomes questionable.

DE Kurath; JR Bontha; DL Blanchard; SK Fiskum; BM Rapko

2000-08-23

198

Glycosaminoglycan sulfation in murine splenocytes  

SciTech Connect

The authors have studied the incorporation of /sup 35/sulfate into glycosaminoglycans (GAG) in splenocytes incubated in medium RPMI 1640 containing 3..mu..M sulfate. Addition of Concanavalin A (Con A) and phorbol 12-myristate 13-acetate (PMA) caused within 24 hr a 10- to 20-fold increase in incorporation into secreted GAG and a 2- to 4-fold increase in cell-retained GAG. PMA added alone caused only 2- to 4-fold increases in both fractions. Between 0 and 3 h however, PMA either alone or with Con A caused a substantial decrease in the incorporation of sulfate into the cellular GAG fraction, suggesting that an immediate effect of these agents is to cause the clearance of nascent GAG chains from the Golgi. The composition of newly sulfated lymphocyte GAG has been found to be approximately 75% chondroitin sulfate and 25% heparan sulfates in both secreted and non-secreted GAG irrespective of the presence of Con A and PMA. Amino column HPLC analysis of disaccharides released by chondroitinase ABC digestion indicates that both ..delta.. Di-4S and ..delta.. Di-6S are produced with the proportion of the latter increasing gradually from initially low levels such that at 24 h, equal proportions of the two are found. Possible mechanisms for this change in the position of sulfation will be discussed.

Rider, C.C.; Hart, G.W.

1986-05-01

199

Relation of precipitation quality to storm type, and deposition of dissolved chemical constituents from precipitation in Massachusetts, 1983-85  

USGS Publications Warehouse

Precipitation samples were collected for 83 storms at a rural inland site in Princeton, Mass., and 73 storms at a rural coastal site in Truro, Mass., to examine the quality of precipitation from storms and relate quality to three storm types (oceanic cyclone, continental cyclone, and cold front). At the inland site, Princeton, ranked-means of precipitation depth, storm duration, specific conductance, and concentrations and loads of hydrogen, sulfate, aluminum, bromide, and copper ions were affected by storm type. At the coastal site, Truro, ranked means of precipitation depth, storm duration, and concentrations and loads of calcium, chloride, magnesium, potassium, and sodium ions were affected by storm type. Precipitation chemistry at the coastal site was 85 percent oceanic in orgin, whereas precipitation 72 kilometers inland was 60 percent hydrogen, nitrate, and sulfate ions, reflecting fossil-fuel combustion. Concentrations and loads for specific conductance and 9 chemical constituents on an annual and seasonal basis were determined from National Atmospheric Deposition Program data for spring 1983 through winter 1985 at Quabbin (rural, inland), Waltham (suburban, inland) and Truro (rural, coastal), Massachusetts. Concentrations of magnesium, potassium, sodium, and chloride concentrations were highest at the coast and much lower inland, with very little difference between Waltham and Quabbin. Loads of ammonium, nitrate, sulfate, and hydrogen are highest at Quabbin and are about equal at Waltham and Truro. About twice as much nitrate and hydrogen and about 35 percent more sulfate is deposited at Quabbin than at Waltham or Truro; this pattern indicates that the interior of Massachusetts receives more acidic precipitation than do the eastern or the coastal areas of Massachusetts.

Gay, F.B.; Melching, C.S.

1995-01-01

200

Mesospheric sulfate aerosol layer  

NASA Astrophysics Data System (ADS)

We investigate the heretofore unstudied role of volcanic and nonvolcanic sulfur aerosols and gases in the mesosphere. Two-dimensional microphysical calculations show that sulfur may be an important source of particles below the cold summer mesopause. Observed increases in SO2 with altitude in the upper stratosphere had previously suggested ultraviolet destruction of H2SO4, discounting its survival in the mesosphere. Laboratory measurements have now ruled out ultraviolet photolysis of H2SO4, however, and a recent proposal of visible and near-infrared photolysis of H2SO4 explains the SO2 observations. Our calculations show that enough H2SO4 survives this weak photolysis mechanism to produce significant sulfate aerosol surface area in the mesosphere. Neutralization of H2SO4 by metals on the surfaces of meteoritic dust is modeled and affects the mesospheric aerosol negligibly. We discuss the possible implications for this new class of particles for the formation of polar mesospheric summer echoes and polar mesospheric clouds in volcanically quiescent and active periods.

Mills, Michael J.; Toon, Owen B.; Thomas, Gary E.

2005-12-01

201

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

PubMed

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 BaHPO? 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 BaHPO? 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 BaHPO? 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 (Ba?(PO?)?) was obtained at pH 11. The compounds BaHPO? and BaO were present at a pH of below 10. PMID:24462085

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

2014-06-01

202

Development of additives in negative active-material to suppress sulfation during high-rate partial-state-of-charge operation of lead–acid batteries  

Microsoft Academic Search

Additives in the negative active-material of lead–acid batteries were examined to determine whether they could prevent progressive accumulation of lead sulfate (PbSO4) in negative plates during high-rate partial-state-of-charge (HRPSoC) operation. This phenomenon is caused by progressive growth of PbSO4 particles and a lack of conductive paths near these PbSO4 particles.Barium sulfate (BaSO4) particles in various sizes and synthetic lignin were

Ken Sawai; Takayuki Funato; Masashi Watanabe; Hidetoshi Wada; Kenji Nakamura; Masaaki Shiomi; Shigeharu Osumi

2006-01-01

203

Co-doped Barium Phosphate Glass  

NASA Astrophysics Data System (ADS)

Co-doping of a P2O5:BaO glass matrix with divalent tin and trivalent samarium ions has been realized by the melt-quenching technique with the purpose of investigating the material's luminescent properties. Photoluminescence excitation spectra obtained by monitoring Sm3+ 4G5/2 emission showed a broad excitation band around 290 nm (absent in a Sm3+-doped reference), typical of donor/acceptor energy transfer. Under such excitation, the material exhibits a reddish-white emission. Time-resolved spectra recorded under the 290-nm excitation (non-resonant with Sm3+ excitation peaks) exposed a broad blue-white band characteristic of twofold-coordinated Sn centers and orange-red emission bands of Sm3+ ions, which appeared well separated in time in accord with their emission decay dynamics. Consequently, the data indicate that light absorption occurs at Sn centers (donors) followed by energy transfer to samarium ions (acceptors) which results in populating the 4G5/2 emitting state in Sm3+. Energy transfer pathways likely resulting in the sensitization of Sm3+ photoluminescence are discussed. Results are put into context in terms of the potential of SnO and rare-earth co-doped barium phosphate glasses for use in white light-emitting devices.

Jiménez, J. A.

2014-09-01

204

The Use of Seaweed and Sugarcane Bagasse for the Biological Treatment of Metal-contaminated Waters Under Sulfate-reducing Conditions  

Microsoft Academic Search

When wetlands reach maximum treatment capacity to remove heavy metals, removal can still take place through precipitation\\u000a as sulfide because of the biological reduction of sulfate. To achieve this goal, anaerobic conditions must be attained, a\\u000a sulfate source must exist, and an adequate substrate for sulfate-reducing bacteria (SRB) is also required. In the present\\u000a work, two ligneous-cellulosic materials, a brown

Márcia Monteiro Machado Gonçalves; Luiz Antonio de Oliveira Mello; Antonio Carlos Augusto da Costa

2008-01-01

205

The Use of Seaweed and Sugarcane Bagasse for the Biological Treatment of Metal-contaminated Waters Under Sulfate-reducing Conditions  

Microsoft Academic Search

When wetlands reach maximum treatment capacity to remove heavy metals, removal can still take place through precipitation\\u000a as sulfide because of the biological reduction of sulfate. To achieve this goal, anaerobic conditions must be attained, a\\u000a sulfate source must exist, and an adequate substrate for sulfate-reducing bacteria (SRB) is also required. In the present\\u000a work, two ligneous-cellulosic materials, a brown

Márcia Monteiro Machado Gonçalves; Luiz Antonio de Oliveira Mello; Antonio Carlos Augusto Costa

206

Meteorological impacts on urban sulfate levels  

Microsoft Academic Search

The effects of various meteorological conditions on ambient sulfate levels in Boston, Mass., are evaluated. Two-hour average samples of total sulfate and total suspended particulate were collected at three urban sites. Meteorological data including barometric pressure, absolute humidity, and wind direction were obtained for each sampling interval. High correlations between sulfate levels and the meteorological variables are noted. A sulfate

W. A. Turner; C. J. Gregory

1980-01-01

207

Affinity Chromatography Media CellufineTM Sulfate  

E-print Network

, chondroitin sulfate or heparin. Matrex Cellufine Sulfate consists of a rigid spherical cellulose matrix of 3Affinity Chromatography Media Matrex® CellufineTM Sulfate For Concentration, Purification and viral or microbial antigens. Matrex Cellufine Sulfate affinity media is a simple, rapid and effective

Lebendiker, Mario

208

Creating unstable velocity-space distributions with barium injections  

SciTech Connect

Large Debye lengths relative to detector dimensions and the absence of confining walls makes space an attractive laboratory for studying fundamental theories of plasma instabilities. However, natural space plasmas are rarely found displaced from equilibrium enough to permit isolation and diagnosis of the controlling parameters and driving conditions. Furthermore, any plasma or field response to the departure from equilibrium can be masked by noise in the natural system. Active experiments provide a technique for addressing the chicken or egg dilemma. Early thermite barium releases were generally conducted at low altitudes from sounding rockets to trace electric fields passively or to study configuration-space instabilities. One can also study velocity-space instabilities with barium releases. Neutral barium vapor releases wherein a typical speed greatly exceeds the thermal speed can be used to produce barium ion velocity-space distributions that should be subject to a number of microinstabilities. We examine the ion velocity-space distributions resulting from barium injections from orbiting spacecraft and shaped-charges.

Pongratz, M.B.

1983-01-01

209

Acceleration of barium ions near 8000 km above an aurora  

NASA Technical Reports Server (NTRS)

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.

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

1984-01-01

210

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

NASA Technical Reports Server (NTRS)

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.

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

1974-01-01

211

Enhanced dielectric properties from barium strontium titanate films with strontium titanate buffer layers  

E-print Network

Enhanced dielectric properties from barium strontium titanate films with strontium titanate buffer in their PE state. One of the leading material candidates for tunable materials is barium strontium titanate

Alpay, S. Pamir

212

Precipitation chemistry in Croatia during the period 1981-2006.  

PubMed

The spatial, temporal changes and trends changes in precipitation chemistry in Croatia during the period 1981-2006 were analysed using data from 27 sampling sites. The origins of air masses that arrived over Croatia were evaluated by the sector analysis of two-dimensional back trajectories. The distribution per sector of the volume-weighted concentrations of the main ions (sulfate, nitrate, chloride, ammonium, calcium, magnesium, sodium, and potassium) and the pH were also inspected. The trend in the annual volume-weighted concentrations of the major ions in precipitation and pH was tested using the nonparametric Mann-Kendall test and Sen's slope estimator. The sulfate and nitrate ion concentrations significantly decreased for the majority of sites. The main decline of the sulfate ion concentration occurred after 1990. Changes in the anthropogenic sulfur emission patterns over Europe in the last two decades resulted in different acidity and sulfate ion concentrations related to a particular sector compared to earlier times. In addition, precipitation chemistry in Croatia was also influenced by geographical and climatological diversity. Finally, the war and post-war activities were identified as possible anthropogenic sources of some base cations, i.e., potassium and calcium. PMID:19557239

Cani?, Kornelija Spoler; Vidic, Sonja; Klai?, Zvjezdana Benceti?

2009-04-01

213

Eos, Vol. 87, No. 49, 5 December 2006 Abundant sulfates appear to exist on the  

E-print Network

that the sul- fate minerals there, particularly acid sulfates such as jarosite, precipitated from high con and have commonly been attributed to a planet-wide volcanogenic `acid fog'--where clouds of acid mist react- centrations of sulfuric acid in flowing and standing water and groundwater. However, such explanations

214

Calcium Sulfate Characterized by ChemCam/Curiosity at Gale Crater, Mars  

NASA Astrophysics Data System (ADS)

Within Gale crater an assemblage of veins were observed, mainly into Yellowknife Bay region. The ChemCam instrument was able to demonstrate they consist of Ca-sulfate veins. We interpret them as a precipitation posterior to the sediments they cross.

Nachon, M.; Clegg, S. M.; Mangold, N.; Schröder, S.; Kah, L. C.; Dromart, G.; Olilla, A.; Johnson, J. R.; Oehler, D. Z.; Bridges, J. C.; Le Mouélic, S.; Forni, O.; Wiens, R. C.; Rapin, W.; Anderson, R. B.; Blaney, D. L.; Bell, J. F.; Clark, B.; Cousin, A.; Dyar, M. D.; Ehlmann, B.; Fabre, C.; Gasnault, O.; Grotzinger, J.; Lasue, J.; Lewin, E.; Léveillé, R.; McLennan, S.; Maurice, S.; Meslin, P.-Y.; Rice, M.; Squyres, S. W.; Stack, K.; Sumner, D. Y.; Vaniman, D.; Wellington, D.

2014-07-01

215

Phenotypic and Behavioral Defects Caused by Barium Exposure in Nematode Caenorhabditis elegans  

Microsoft Academic Search

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,\\u000a generation time, head thrash, and body bend were selected for the assessment of barium toxicity. High concentrations (75 ?M\\u000a and 200 ?M) of barium exposure caused severe life-span defects. Body

D.-Y. Wang; Y. Wang

2008-01-01

216

Barium Levels in Soils and Centella asiatica  

PubMed Central

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 [?g/g dry weight (dw)] was 63.72 to 382.01 ?g/g in soils while in C. asiatica, Ba concentrations ranged from 5.05 to 21.88 ?g/g for roots, 3.31 to 11.22 ?g/g for leaves and 2.37 to 6.14 ?g/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

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

2013-01-01

217

Barium Levels in Soils and Centella asiatica.  

PubMed

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 [?g/g dry weight (dw)] was 63.72 to 382.01 ?g/g in soils while in C. asiatica, Ba concentrations ranged from 5.05 to 21.88 ?g/g for roots, 3.31 to 11.22 ?g/g for leaves and 2.37 to 6.14 ?g/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

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

2013-08-01

218

[The evaluation of the presumed mutagenic activity of barium nitrate].  

PubMed

Barium nitrate, which is used in industry in the production of green signal lights, to remove gases from vacuum tubes, and in the production of barium oxide, was assayed to assess the possible mutagenic effects using both the Ames test (S. typhimurium TA 1535, TA 1537, TA 1538, TA 97a, TA 98, TA 100, TA 102c), with and without metabolic activation with the plate incorporation assay and pre-incubation assay methods, and using the mitotic crossing over test, the mitotic genic conversion test, and the retromutation test in Saccharomyces cerevisiae, D7 strain, with and without metabolic activation. In the experimental conditions of the study, at various gradually increasing concentrations, barium nitrate gave negative results. PMID:1803207

Monaco, M; Dominici, R; Barisano, P; Di Palermo, G

1991-01-01

219

Electro-optical polycrystalline barium lanthanum titanium niobate  

SciTech Connect

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.

Mehrotra, A.K.

1991-02-19

220

Appendicitis in children. Accuracy of the barium enema.  

PubMed

The barium enema (BE) may be useful in the diagnosis of atypical appendicitis in children. We analyzed our experience with 18 children in whom appendicitis was suspected and BE was performed. All of the children underwent surgical exploration. Nonfilling of the appendix with cecal indentation, extravasation of barium from the appendix, or both, were considered positive signs of an inflamed appendix on BE. Using these criteria, 12 of 14 cases of proved appendicitis were true positive and two were equivocal. Four children were proved not to have appendicitis; one of these patients had a true-negative BE, two had equivocal BEs, and there was one false-positive BE (Schönlein-Henoch purpura). Extravasation of barium into the peritoneal cavity was noted in one patient; this was a rare complication. PMID:3687874

Garcia, C; Rosenfield, N S; Markowitz, R I; Seashore, J H; Touloukian, R J; Cicchetti, D V

1987-12-01

221

Multiphoton laser ionization for energy conversion in barium vapor  

NASA Astrophysics Data System (ADS)

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.

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

2013-03-01

222

Enzyme precipitate coatings of lipase on polymer nanofibers.  

PubMed

Lipase (LP) was immobilized on electrospun and ethanol-dispersed polystyrene-poly(styrene-co-maleic anhydride) (PS-PSMA) nanofibers (EtOH-NF) in the form of enzyme precipitate coatings (EPCs). LP precipitate coatings (EPCs-LP) were prepared in a three-step process, consisting of covalent attachment, LP precipitation, and crosslinking of precipitated LPs onto the covalently attached LPs via glutaraldehyde treatment. The LP precipitation was performed by adding various concentrations of ammonium sulfate (20-50%, w/v). EPCs-LP improved the LP activity and stability when compared to covalently attached LPs (CA-LP) and the enzyme coatings of LPs (EC-LP) without the LP precipitation. For example, the use of 40% (w/v) ammonium sulfate resulted in EPC40-LP with the highest activity, which was 4.0 and 3.6 times higher than those of CA-LP and EC-LP, respectively. After 165-day incubation under rigorous shaking at 200 rpm, the residual activities of EPC50-LP were 0.5 ?M/min mg of EtOH-NF, representing 113 and 75 times higher than those of CA-LP and EC-LP, respectively. When LP was partially purified via a simple ammonium sulfate precipitation and dialysis, both activities and stabilities of EC-LP and EPC-LP could be marginally improved. It is anticipated that the improved LP activity and stability in the form of EPCs would allow for their potential applications in various bioconversion processes such as biodiesel production and ibuprofen resolution. PMID:21409450

An, Hyo Jin; Lee, Hye-Jin; Jun, Seung-Hyun; Hwang, Sang Youn; Kim, Byoung Chan; Kim, Kwanghee; Lee, Kyung-Mi; Oh, Min-Kyu; Kim, Jungbae

2011-09-01

223

The Contact Difference of Potential Between Barium and Zinc The External Work Function of Zinc  

Microsoft Academic Search

The methods of contact potential measurement described in previous reports of this series have been extended to zinc, for which the published work function data are discordant. Measurement was by the retarding potential method with variable anode, in tubes sealed from the pumps and gettered with vaporized barium. Barium was the reference metal and the measured surfaces of both barium

Paul A. Anderson

1940-01-01

224

Sputtering of a hydrogenated barium surface in a negative ion surface conversion source  

Microsoft Academic Search

Both the production of negative hydrogen ions on a barium surface and surface sputtering under low energy (~ 200 eV) intense particle bombardment is studied in the FOM Surface Conversion Experiment. We have observed a decrease in barium sputter-yield when a barium surface is exposed to an intense positive hydrogen or deuterium ion flux, extracted from a plasma. This effect

R. M. A. Heeren; D. Ciric; S. Yagura; H. J. Hopman; A. W. Kleyn

1992-01-01

225

Barium Titanate Nanoparticles in Block Copolymer Tu Lee,*,, Nan Yao, Hiroaki Imai,, and Ilhan A. Aksay,  

E-print Network

Barium Titanate Nanoparticles in Block Copolymer Tu Lee,*,, Nan Yao, Hiroaki Imai,, and Ilhan A-polybutadiene-polystyrene (Kraton D1102). The barium titanated Kraton thin film had remnants of the cylindrical morphology of a plain Kraton thin film with an interdomain spacing of 23 nm. The procedure of barium titanation

Aksay, Ilhan A.

226

Discrete Barium Strontium Titanate (BST) Thin-Film Interdigital Varactors on Alumina: Design, Fabrication, Characterization, and  

E-print Network

Discrete Barium Strontium Titanate (BST) Thin-Film Interdigital Varactors on Alumina: Design, Raleigh, NC-27695-7914, USA. Email:jayeshnath@ieee.org Abstract -- Discrete Barium Strontium Titanate (BST, capacitors, BST, ferroelectric, thin-film, barium strontium titanate, bandpass filter, IP3, ACPR, temperature

227

40 CFR 721.10010 - Barium manganese oxide (BaMnO3).  

...2014-07-01 2014-07-01 false Barium manganese oxide (BaMnO3). 721.10010 Section...Chemical Substances § 721.10010 Barium manganese oxide (BaMnO3 ). (a) Chemical...chemical substance identified as barium manganese oxide (BaMnO3 ) (PMN...

2014-07-01

228

40 CFR 721.10010 - Barium manganese oxide (BaMnO3).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Barium manganese oxide (BaMnO3). 721.10010 Section...Chemical Substances § 721.10010 Barium manganese oxide (BaMnO3 ). (a) Chemical...chemical substance identified as barium manganese oxide (BaMnO3 ) (PMN...

2013-07-01

229

40 CFR 721.10010 - Barium manganese oxide (BaMnO3).  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Barium manganese oxide (BaMnO3). 721.10010 Section...Chemical Substances § 721.10010 Barium manganese oxide (BaMnO3). (a) Chemical...chemical substance identified as barium manganese oxide (BaMnO3 ) (PMN...

2010-07-01

230

40 CFR 721.10010 - Barium manganese oxide (BaMnO3).  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Barium manganese oxide (BaMnO3). 721.10010 Section...Chemical Substances § 721.10010 Barium manganese oxide (BaMnO3). (a) Chemical...chemical substance identified as barium manganese oxide (BaMnO3 ) (PMN...

2011-07-01

231

40 CFR 721.10010 - Barium manganese oxide (BaMnO3).  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Barium manganese oxide (BaMnO3). 721.10010 Section...Chemical Substances § 721.10010 Barium manganese oxide (BaMnO3 ). (a) Chemical...chemical substance identified as barium manganese oxide (BaMnO3 ) (PMN...

2012-07-01

232

Compact pulse forming line using barium titanate ceramic material  

NASA Astrophysics Data System (ADS)

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 ? 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.

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

2011-11-01

233

Isotope evidence for secondary sulfide precipitation along the Marsyandi River, Nepal, Himalayas  

NASA Astrophysics Data System (ADS)

We present sulfur and oxygen isotope data from 41 samples of dissolved riverine sulfate from along 65 km of the Marsyandi River in the Northern Himalayas. Coupled sulfur and oxygen isotopic composition of riverine sulfate (?34S and ?18O respectively) yield unique constraints on the source of sulfur to the river system. The headwaters of the Marsyandi River have light ?34S and ?18O, which requires that the source of sulfate to the river is through the anoxic weathering of pyrite (likely via Fe3+). The ?34S and ?18O of sulfate in tributaries to the Marsyandi increase downstream, which could result either from inputs from evaporites or bacterial sulfate reduction with subsequent sulfide precipitation in warmer and wetter catchments; either of these processes could result in heavy ?34S and ?18O of the residual river sulfate. Elemental ratios such as Sr/Ca and Ca/SO4 suggest, as previous studies have also concluded, that evaporite weathering is not important in the Marsyandi River. We conclude that the isotope data is most consistent with the onset of bacterial sulfate reduction and secondary sulfide precipitation in the soils in the warmer and wetter downstream catchments. Our results have implications for understanding the source of sulfate to the ocean as well as the redox and acidity budget within rapidly eroding catchments.

Turchyn, Alexandra V.; Tipper, Edward T.; Galy, Albert; Lo, Jun-Kai; Bickle, Mike J.

2013-07-01

234

Study of the photovoltaic effect in thin film barium titanate  

NASA Technical Reports Server (NTRS)

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.

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

1981-01-01

235

Ionization and expansion of barium clouds in the ionosphere  

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

236

Could binary mixture of Nd-Ni ions control the electrical behavior of strontium-barium M-type hexaferrite nanoparticles?  

SciTech Connect

Research highlights: {yields} Strontium-barium hexaferrites (Sr{sub 0.5}Ba{sub 0.5}Fe{sub 12}O{sub 19}) in single magnetoplumbite phase solid structure are synthesized by the co-precipitation method. {yields} Structural and electrical properties of Nd-Ni substituted ferrites are investigated. {yields} These ferrite materials possess high electrical resistivity (108 {Omega} cm) that is essential to curb the eddy current loss, which is pre-requisite for surface mount devices. -- Abstract: Cationic substitution in M-type hexaferrites is considered to be an important tool for modification of their electrical properties. This work is part of our comprehensive study on the synthesis and characterization of Nd-Ni doped strontium-barium hexaferrite nanomaterials of nominal composition Sr{sub 0.5}Ba{sub 0.5-x}Nd{sub x}Fe{sub 12-y}Ni{sub y}O{sub 19} (x = 0.00-0.10; y = 0.00-1.00). Doping with this binary mixture modulates the physical and electrical properties of strontium-barium hexaferrite nanoparticles. Structural and electrical properties of the co-precipitated ferrites are investigated using state-of-the-art techniques. The results of X-ray diffraction analysis reveal that the lattice parameters and cell volume are inversely related to the dopant content. Temperature dependent DC-electrical resistivity measurements infer that resistivity of strontium-barium hexaferrites decreases from 1.8 x 10{sup 10} to 2.0 x 10{sup 8} {Omega} cm whereas the drift mobility, dielectric constant and dielectric loss tangent are directly related to the Nd-Ni content. The results of the study demonstrate a relationship between the modulation of electrical properties of substituted ferrites and nature of cations and their lattice site occupancy.

Iqbal, Muhammad Javed, E-mail: mjiqauchem@yahoo.com [Surface and Solid State Chemistry Laboratory, Department of Chemistry, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Farooq, Saima [Surface and Solid State Chemistry Laboratory, Department of Chemistry, Quaid-i-Azam University, Islamabad 45320 (Pakistan)] [Surface and Solid State Chemistry Laboratory, Department of Chemistry, Quaid-i-Azam University, Islamabad 45320 (Pakistan)

2011-05-15

237

Early Triassic seawater sulfate drawdown  

NASA Astrophysics Data System (ADS)

The marine sulfur cycle is intimately linked to global carbon fluxes, atmospheric composition, and climate, yet relatively little is known about how it responded to the end-Permian biocrisis, the largest mass extinction of the Phanerozoic. Here, we analyze carbonate-associated-sulfate (CAS) from three Permo-Triassic sections in South China in order to document the behavior of the C-S cycle and its relationship to marine environmental changes during the mass extinction and its aftermath. We find that ?34SCAS varied from +9‰ to +44‰ at rates up to 100‰ Myr-1 during the Griesbachian-Smithian substages of the Early Triassic. We model the marine sulfur cycle to demonstrate that such rapid variation required drawdown of seawater sulfate concentrations to ?4 mM and a reduction in its residence time to ?200 kyr. This shorter residence time resulted in positive covariation with ?13Ccarb due to strong coupling of the organic carbon and pyrite burial fluxes. Carbon and sulfur isotopic shifts were associated with contemporaneous changes in climate, marine productivity, and microbial sulfate reduction rates, with negative shifts in ?13Ccarb and ?34SCAS linked to warming, decreased productivity, and reduced sulfate reduction. Sustained cooling during the Spathian re-invigorated oceanic overturning circulation, reduced marine anoxia, and limited pyrite burial. As seawater sulfate built to higher concentrations during the Spathian, the coupling of the marine C and S cycles came to an end and a general amelioration of marine environmental conditions set the stage for a recovery of invertebrate faunas. Variation in seawater sulfate during the Early Triassic was probably controlled by climate change, possibly linked to major eruptive phases of the Siberian Traps.

Song, Huyue; Tong, Jinnan; Algeo, Thomas J.; Song, Haijun; Qiu, Haiou; Zhu, Yuanyuan; Tian, Li; Bates, Steven; Lyons, Timothy W.; Luo, Genming; Kump, Lee R.

2014-03-01

238

Wastewater treatment using ferrous sulfate  

SciTech Connect

Treatment of industrial wastewater with coagulants is used extensively in the thorough removal of emulsified tars and oils. The central plant laboratory at the Zhdanov Coke Works conducted investigations of the treatment of wastewater, subsequently used for quenching coke, with ferrous sulfate. Laboratory tests and subsequent industrial tests demonstrated the efficiency of the method. In order to further intensify the wastewater treatment process we conducted laboratory tests with the addition of certain quantities of other coagulation reagents, for example polyacrylamide (PAA) and caustic soda, in addition to the ferrous sulfate. The combined use of polyacrylamide and ferrous sulfate permits instant coagulation of the sludge and very rapid (5 to 10 min) clarification of the water. In addition, in this case the degree of purification of the water is less dependent on the initial concentration of impurities. The purification is also improved when caustic soda is added, raising the pH. From the data it is apparent that an identical degree of purification of the water may be achieved either by increasing the consumption of ferrous sulfate, or by adding PAA or NaOH. During industrial tests of the purification of wastewater with ferrous sulfate, we also investigated the resulting sludge. The use of ferrous sulfate causes a significant increase in its quantity (by a factor of 1.5 to 1.8) and in its oil content (by a factor of 2 to 2.5). The water content in the sludge decreases. The sludge (in the quantity of 0.6% of the charge) may be added to the coking charge.

Boetskaya, K.P.; Ioffe, E.M.

1980-01-01

239

Aerobic sulfate reduction in microbial mats  

NASA Technical Reports Server (NTRS)

Measurements of bacterial sulfate reduction and dissolved oxygen (O2) in hypersaline bacterial mats from Baja California, Mexico, revealed that sulfate reduction occurred consistently within the well-oxygenated photosynthetic zone of the mats. This evidence that dissimilatory sulfate reduction can occur in the presence of O2 challenges the conventional view that sulfate reduction is a strictly anaerobic process. At constant temperature, the rates of sulfate reduction in oxygenated mats during daytime were similar to rates in anoxic mats at night: thus, during a 24-hour cycle, variations in light and O2 have little effect on rates of sulfate reduction in these mats.

Canfield, Donald E.; Des Marais, David J.

1991-01-01

240

Precipitate in Magnesium  

NASA Astrophysics Data System (ADS)

We performed molecular dynamics simulations and investigated interactions between a Mg17Al12 precipitate and a basal dislocation in magnesium. Modified embedded-atom method potentials for multiple-component systems were used in our simulations. The simulation results show that the basal dislocation is able to shear through the matrix and the precipitate/matrix interface, without creating a loop around the precipitate. The precipitate is only elastically deformed by the external shear strain. This interaction can be considered an extreme case of the Orowan mechanism when the strength of the precipitate/matrix interface is weak. Cross slip of the basal dislocation was observed when the precipitate size was 3.0 nm. The dislocation changed its slip plane to another basal plane via the prismatic and the pyramidal planes, creating jogs on these non-basal planes. The jogs had low mobility and debris was created when the jogs were dragged forward by the Shockley partial dislocations.

Liao, Min; Li, B.; Horstemeyer, M. F.

2014-07-01

241

COMPLEXOMETRIC TITRATION OF RARE EARTH ELEMENTS. DISSOLUTION OF THE RARE EARTH OXALATE WITH ETHYLENEDIAMINETETRAACETIC ACID AND BACK TITRATION WITH MAGNESIUM SULFATE  

Microsoft Academic Search

The processes for dissolution of the oxalate and complexometry to ; determine the small amounts of rare earth rapidly and accurately, were studied. ; Crystalline rare earth oxalate was precipitated and filtered. The precipitate ; was dissolved completely with EDTA in alkaline solution and the excess of EDTA in ; solution was back titrated with standard magnesium sulfate solution. By

Seizo Misumi; Tomitsugu Taketatsu

1959-01-01

242

Chiral Crystallization of Ethylenediamine Sulfate  

ERIC Educational Resources Information Center

The optimal conditions for the crystallization of achiral ethylenediamine sulfate into large chiral crystals that are ideal for polarimetry studies and observation using Polaroid sheets are presented. This experiment is an ideal undergraduate experiment, which clearly demonstrates the chiral crystallization of an achiral molecule.

Koby, Lawrence; Ningappa, Jyothi B.; Dakesssian, Maria; Cuccia, Louis A.

2005-01-01

243

DYNAMICS OF AUTOMOTIVE SULFATE EMISSIONS  

EPA Science Inventory

A preliminary assessment of the potential environmental impact of automotive sulfuric acid (or sulfate) aerosol has been made by analyzing the aerosol dynamics. This analysis leads to the prediction of ambient automotive sulfuric acid aerosol concentrations over and around a larg...

244

Microbial sulfation of 8-prenylnaringenin.  

PubMed

Out of 24 fungal strains tested for their ability to transform 8-prenylnaringenin, Syncephalastrum racemosum was found to convert this phytoestrogen to a sulfate derivative. The conjugation with sulfuric acid observed in this study is paralleled in mammals indicating that microbes can be used to mimic mammalian metabolism. PMID:23923620

Bartma?ska, Agnieszka; Tronina, Tomasz; Huszcza, Ewa

2013-01-01

245

High average power generation in barium nitrate Raman laser  

NASA Astrophysics Data System (ADS)

The generation of low divergent ( M 2?1.5) first and third Stokes radiation in a barium nitrate Raman laser with average powers of 11 W and 5 W, respectively, was demonstrated. The quantum conversion efficiency was up to 21%. The possibility of thermal lens compensation in such Raman lasers was shown.

Lisinetskii, V. A.; Riesbeck, T.; Rhee, H.; Eichler, H. J.; Orlovich, V. A.

2010-04-01

246

Patient and occupational dosimetry in double contrast barium enema examinations  

Microsoft Academic Search

A new and relatively simple method is presented to distribute total dose-area product (DAP) over a number of projections that model exposure during double contrast barium enema (DCBE) examinations. In addition, hitherto unavailable entrance and effective doses to the physician performing the DCBE examination have been determined. DAP, fluoroscopy time, number of images as well as some patient data were

G J KEMERINK; A C W BORSTLAP; M J FRANTZEN; F W SCHULTZ; J ZOETELIEF; JMA VAN ENGELSHOVEN

247

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 ...

248

HEALTH EFFECTS OF HUMAN EXPOSURE TO BARIUM IN DRINKING WATER  

EPA Science Inventory

The overall objective of this study was to examine by epidemiologic and supportive laboratory studies, the human health effects associated with ingestion of barium in drinking water exceeding the U.S. drinking water standard of 1.0 mg/l. The incidence of cardiovascular mortality ...

249

Barium strontium titanate powders prepared by spray pyrolysis  

Microsoft Academic Search

Ultasonic spray pyrolysis (SP) has been investigated for the production of the barium strontium titanate (BST) powders from the polymeric precursors. The processing parameters, such as flux of aerosol and temperature profile inside the furnace, were optimized to obtain single phase BST. The powders were characterized by the methods of X-ray diffraction analysis, SEM, EDS and TEM. The obtained powders

G. Brankovi?; Z. Brankovi?; M. S. Góes; C. O. Paiva-Santos; M. Cilense; J. A. Varela; E. Longo

2005-01-01

250

Dynamics of a barium release in the magnetospheric tail  

NASA Technical Reports Server (NTRS)

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.

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

1989-01-01

251

BARIUM AND RADIUM IN WATER TREATMENT PLANT WASTES  

EPA Science Inventory

Water treatment plants at nine locations (10 plants) in Illinois and Iowa were studied to determine the characteristics and disposal practices for the sludge, brine, and backwash water containing radium (Ra) and/or barium (Ba). The treatment processes in these ten plants include ...

252

Barium-140 from irradiated uranium-233 without a carrier  

SciTech Connect

The optimum conditions for uranium-233 irradiation have been selected to obtain barium-140. The latter has been isolated without a carrier in a chromatographic column packed with KRS-8 cation-exchange resin (sulfocationite) with a yield of 83 +/- 6% and a radiochemical purity of 99.7% by its elutriation with ammonium acetate solution and subsequent sublimation.

Bulatenkov, Yu.V.; Gedeonov, A.D.; Mozzhukhin, A.V.

1987-09-01

253

Adsorption of oxygen on clean and barium covered copper surfaces: an XPS, UPS and AES study  

NASA Astrophysics Data System (ADS)

XPS studies of oxygen on barium covered copper surface show two types of dissociatively chemisorbed species, viz. O x- (529.5 eV) and Oy- (531.6 eV) ( x) < y < 2). This is supported by He II spectra which show two peaks at 6 and 9.2 eV below EF. While dissociatively chemisorbed oxygen on clean copper seen at 530 eV is strongly held even up to 700 K, the oxygen on barium covered surface starts desorbing at 450 K. The surface stoichiometry of oxygen to barium has been estimated both as functions of barium coverage and of temperature for a given barium concentration. The Cu(L 3VV)/Cu(L 3M 23M 23) Auger ratio technique has been employed to show charge transfer from barium to copper on the barium covered surface and from copper to oxygen on subsequent oxygen adsorption.

Ayyoob, M.; Hegde, M. S.

1984-11-01

254

Urban impacts on precipitation  

NASA Astrophysics Data System (ADS)

Weather and climate changes caused by human activities (e.g., greenhouse gas emissions, deforestation, and urbanization) have received much attention because of their impacts on human lives as well as scientific interests. The detection, understanding, and future projection of weather and climate changes due to urbanization are important subjects in the discipline of urban meteorology and climatology. This article reviews urban impacts on precipitation. Observational studies of changes in convective phenomena over and around cities are reviewed, with focus on precipitation enhancement downwind of cities. The proposed causative factors (urban heat island, large surface roughness, and higher aerosol concentration) and mechanisms of urban-induced and/or urban-modified precipitation are then reviewed and discussed, with focus on downwind precipitation enhancement. A universal mechanism of urban-induced precipitation is made through a thorough literature review and is as follows. The urban heat island produces updrafts on the leeward or downwind side of cities, and the urban heat island-induced updrafts initiate moist convection under favorable thermodynamic conditions, thus leading to surface precipitation. Surface precipitation is likely to further increase under higher aerosol concentrations if the air humidity is high and deep and strong convection occurs. It is not likely that larger urban surface roughness plays a major role in urbaninduced precipitation. Larger urban surface roughness can, however, disrupt or bifurcate precipitating convective systems formed outside cities while passing over the cities. Such urban-modified precipitating systems can either increase or decrease precipitation over and/or downwind of cities. Much effort is needed for in-depth or new understanding of urban precipitation anomalies, which includes local and regional modeling studies using advanced numerical models and analysis studies of long-term radar data.

Han, Ji-Young; Baik, Jong-Jin; Lee, Hyunho

2014-01-01

255

21 CFR 184.1315 - Ferrous sulfate.  

Code of Federal Regulations, 2010 CFR

... O, CAS Reg. No. 7782-63-0) is prepared by the action of sulfuric acid on iron. It occurs as pale, bluish-green crystals or granules. Progressive heating of ferrous sulfate heptahydrate produces ferrous sulfate (dried). Ferrous...

2010-04-01

256

21 CFR 184.1315 - Ferrous sulfate.  

... O, CAS Reg. No. 7782-63-0) is prepared by the action of sulfuric acid on iron. It occurs as pale, bluish-green crystals or granules. Progressive heating of ferrous sulfate heptahydrate produces ferrous sulfate (dried). Ferrous...

2014-04-01

257

21 CFR 186.1797 - Sodium sulfate.  

Code of Federal Regulations, 2010 CFR

...RECOGNIZED AS SAFE Listing of Specific Substances Affirmed as GRAS § 186.1797 Sodium sulfate. (a) Sodium sulfate (Na2 SO4 , CAS Reg. No. 7757-82-6), also known as Glauber's salt, occurs naturally and exists as colorless...

2010-04-01

258

Sulfite-sulfide-sulfate-carbonate equilibria with applications to Mars  

NASA Astrophysics Data System (ADS)

Mars volcanic SO2 and H2S gas emissions are likely the dominant source of martian sulfate, and the source of sulfuric acid. Until this work, the FREZCHEM model lacked SO2 and H2S gases and associated sulfite and sulfide minerals. The specific objectives of this paper were to add these components and associated sulfite and sulfide minerals and phases into FREZCHEM, and to explore some possible roles of these chemistries on Mars. New solid phases added included the sulfites: Na2SO3·7H2O, K2SO3, (NH4)2SO3·H2O, MgSO3·6H2O, CaSO3·0.5H2O, and FeSO3·1.5H2O, and the sulfide: FeS2. The lowest eutectic of these minerals was K2SO3 (= 6.57 m) at 228 K. Because sulfurous acid is stronger than carbonic acid, this causes a much larger fraction of S(IV) to exist as sulfite (SO32-) at acidic to mildly alkaline pH, whereas almost none of the C is present as carbonate anion. Model calculations show that small quantities of SO2 in an early CO2-rich martian atmosphere suppressed formation of carbonates because SO2 is much more water soluble than CO2 and a stronger acid, which may be a major reason why sulfates are much more common than carbonates on Mars. Also, perhaps equally important are low temperatures that favor sulfite mineral precipitation, the oxidation of which leads to sulfate minerals. Another potentially important factor that favors sulfite/sulfide mineral formation is low pH values that cannot allow carbonate minerals, but can allow sulfide minerals such as pyrite (FeS2). The presence of pyrite, highly insoluble, would lead to sulfate minerals when oxygen becomes available in acidic environments. Major cations for both sulfites (or sulfates) and carbonates (Ca and Mg) can limit carbonates. Sulfite-sulfide volcanism on a cold, lower pH, Mars are the primary causes of high sulfate minerals (e.g., Ca and Mg sulfates), compared to volcanism on a warm, higher pH, Earth that led to more abundant carbonate minerals (e.g., Ca and Mg carbonates).

Marion, G. M.; Kargel, J. S.; Crowley, J. K.; Catling, D. C.

2013-07-01

259

Mesoscale Banded Precipitation  

NSDL National Science Digital Library

Precipitation frequently falls and accumulates in discrete bands with accumulations that vary markedly over short distances. This module examines several mechanisms that result in mesoscale banded precipitation, focusing primarily on processes at work in midlatitude cyclones. The module starts with a review of the Norwegian and conveyor belt cyclone models. Then several banding processes are examined in detail, including deformation/frontogenesis, the Trowal (Trough of Warm Air Aloft), frontal merger, CSI/slantwise convection, and melting/evaporation-induced circulations. The module concludes with discussions of the representation of banded precipitation by NWP models and the detection of banded precipitation with satellite sensors.

Comet

2005-06-24

260

Uncertainties in Arctic precipitation  

NASA Astrophysics Data System (ADS)

Precipitation is an essential and highly variable component of the freshwater budget, and solid precipitation in particular, has a major impact on the local and global climate. The impacts of snow on the surface energy balance are tremendous, as snow has a higher albedo than any other naturally occurring surface condition. Documenting the instrumentally observed precipitation climate records presents its own challenges since the stations themselves undergo many changes in the course of their operation.Though it is crucial to accurately measure precipitation as a means to predict change in future water budgets, estimates of long-term precipitation are riddled with measurement biases. Some of the challenges facing reliable measurement of solid precipitation include missing data, gage change, discontinued stations, trace precipitation, blizzards, wetting losses when emptying the gage, and evaporation between the time of event and the time of measurement. Rain measurements likewise face uncertainties such as splashing of rain out of the gage, evaporation, and extreme events, though the magnitude of these impacts on overall measurement is less than that faced by solid precipitation. In all, biases can be so significant that they present major problems for the use of precipitation data in climate studies.

Majhi, Ipshita; Alexeev, Vladimir; Cherry, Jessica; Groisman, Pasha; Cohen, Judah

2013-04-01

261

Global Precipitation Measurement  

NASA Technical Reports Server (NTRS)

This chapter begins with a brief history and background of microwave precipitation sensors, with a discussion of the sensitivity of both passive and active instruments, to trace the evolution of satellite-based rainfall techniques from an era of inference to an era of physical measurement. Next, the highly successful Tropical Rainfall Measuring Mission will be described, followed by the goals and plans for the Global Precipitation Measurement (GPM) Mission and the status of precipitation retrieval algorithm development. The chapter concludes with a summary of the need for space-based precipitation measurement, current technological capabilities, near-term algorithm advancements and anticipated new sciences and societal benefits in the GPM era.

Hou, Arthur Y.; Skofronick-Jackson, Gail; Kummerow, Christian D.; Shepherd, James Marshall

2008-01-01

262

Ultra-low temperature processing of barium tellurate dielectrics  

NASA Astrophysics Data System (ADS)

Ceramics, metals and polymers have unique electrical properties that are combined for electronic devices and systems. It necessitates lower processing temperatures for ceramics to be compatible with metal and polymer systems. In this thesis, the synthesis, crystal structure, and dielectric properties of barium tellurate are studied for temperatures between 500 and 900°C. Barium tellurate dielectric ceramics (BaTe4O9, BaTe 2O5, BaTe2O6, BaTeO3, BaTeO 4, and Ba2TeO5) are extensively investigated as new LTCC (Low-Temperature Cofired Ceramics) dielectric systems integrated with low resistivity metal electrodes such as silver and aluminum for microwave application. Studies on the phase formation and crystal structure through thermal analyses (Differential Scanning Calorimetry and Thermogravimetric Analysis, DSC-TGA) and X-ray diffraction phase analysis attest that barium tellurates are formed in the temperature range of 500 ˜ 900°C, through the sequential phase formations from Te-rich to Ba-rich phases. The oxygen coordination of the tellurium ion progresses from TeO4 to TeO6 via TeO 3+1 and TeO3 with increasing barium content as confirmed by structural analysis using infrared spectroscopy. High density barium tellurate ceramics are achieved at temperatures as low as 550°C, which provides the potential to be co-fired with low-melting aluminum metal electrodes in LTCC processing. Dielectric permittivity, loss, and temperature stability of barium tellurate dielectric ceramics were measured from 100 Hz to 13 GHz. Barium tellurate ceramics exhibit excellent microwave dielectric properties with intermediate dielectric permittivities and high quality factors (Q). The dielectric properties at microwave frequencies are epsilonr = 17.5, Qxf = 54700 GHz, TCf = -90 ppm/°C for BaTe4O9, epsilonr = 21, Qxf = 50300 GHz, TCf = -51 ppm/°C for BaTe2O6, epsilonr = 10, Qxf = 34000 GHz, TCf = -54 ppm/°C for BaTeO3, and epsilonr = 17, Qx f = 49600 GHz, TCf = -124 ppm/°C for Ba 2TeO5. Co-firing studies of barium tellurate ceramics with metal electrodes establish new LTCC systems for microwave devices. Chemical compatibility of barium tellurates with silver electrodes was achieved in the barium rich compositions. Ba2TeO5 was found to be covetable with silver electrodes at 850°C by adding CuO and B2O3 as fluxing agents. During the co-firing, a thin interfacial layer of AgTe is metastable according to the thermodynamic equilibrium between the Ba2TeO5-Ag/Ag 2O pseudo-binary system. A breakthrough LTCC technology with aluminum is based upon the ultra-low processing temperature and chemical compatibility of BaTe4O 9, which enables co-firing and fabrication of multilayer ceramic capacitors (MLCCs) with aluminum inner electrodes. The aluminum base metal electrode (BME) BaTe4O9 MLCCs provide good dielectric properties of epsilonr = 17.5, TCepsilon = 100 ppm/°C, and tan delta = 2.1 x 10-3 (Q ? 500) at 1 MHz, which are suitable for the class-1 MLCCs. Aluminum microstrip ring resonators on the BaTe4O9 substrates realized good electromagnetic performance of the new materials at microwave frequency exhibiting resonant frequency of 2.97 GHz and Q factor of 278.

Kwon, Do-Kyun

263

Recalibrating the concentration of Precambrian seawater sulfate  

Microsoft Academic Search

The isotopic offset between sulfate sulfur and sulfide sulfur (delta34Ssulfate-sulfide) is widely used in the Precambrian as a paleo-indicator of seawater sulfate concentrations. Popularized by experimental work proposing an increase in seawater sulfate at the Archean - Proterozoic boundary, the concept of using a calibrated physiological process (dissimilatory sulfate reduction) to extract environmental information holds the potential to unlock numerous

D. T. Johnston; A. S. Bradley; A. Hoarfrost; P. R. Girguis

2010-01-01

264

FT Raman investigation of sodium cellulose sulfate  

Microsoft Academic Search

FT Raman investigation of sodium cellulose sulfates (NaCS) was reported. Different NaCS were prepared by two diverse sulfation\\u000a methods and their total degrees of substitution (DS) of sulfate groups were determined through either 13C-NMR spectroscopy or elemental analysis. Subsequently, these NaCS were characterized with FT Raman spectroscopy. The caused\\u000a bands through the introduction of the sulfate groups in cellulose chain

Kai Zhang; Erica Brendler; Steffen Fischer

2010-01-01

265

Meteorological impacts on urban sulfate levels  

SciTech Connect

The effects of various meteorological conditions on ambient sulfate levels in Boston, Mass., are evaluated. Two-hour average samples of total sulfate and total suspended particulate were collected at three urban sites. Meteorological data including barometric pressure, absolute humidity, and wind direction were obtained for each sampling interval. High correlations between sulfate levels and the meteorological variables are noted. A sulfate prediction model based on multiple linear regression is presented. (4 graphs, 19 references, 2 tables)

Turner, W.A.; Gregory, C.J.

1980-04-01

266

Benzene Oxidation Coupled to Sulfate Reduction  

Microsoft Academic Search

(14C)benzene tracer was included with the benzene added to benzene-adapted sediments, 92% of the added radioactivity was recovered as 14CO2. Molybdate, an inhibitor of sulfate reduction, inhibited benzene uptake and production of 14CO2from ( 14 C)benzene. Benzene metabolism stopped when the sediments became sulfate depleted,andbenzeneuptakeresumedwhensulfatewasaddedagain.Thestoichiometryofbenzeneuptakeand sulfate reduction was consistent with the hypothesis that sulfate was the principal electron acceptor for

DEREK R. LOVLEY; JOHN D. COATES; JOAN C. WOODWARD; ANDELIZABETH J. P. PHILLIPS

1995-01-01

267

Preliminary study of the CRRES magnetospheric barium releases  

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

268

[Detergents and precipitation of serum lipoproteins by antisera (author's transl)].  

PubMed

By using gel diffusion methods, it was shown that during immunoelectrophoresis and double diffusion in two dimensions, anionic detergents (sodium oleate, sodium desoxycholate, sodium lauryl-sulfate and sodium decyl-sulfate), added to human serum at the final concentration of 0.5%, do not prevent the formation of an insoluble antigen-antibody complex (precipitation line) when specific antibodies react with serum lipoproteins: LDL, HDL and VLDL. In spite of the presence of anionic detergents, the antigen-antibody interaction in gel occurs even if the amount of lipoproteins in serum was highly reduced. On the contrary, the non ionic detergent tween 80, has a strong inhibitory effect on the specific precipitation of lipoproteins, especially in the case of HDL. PMID:823526

Burstein, M; Legmann, P

1976-01-01

269

Sulfates on Mars: A systematic Raman spectroscopic study of hydration states of magnesium sulfates  

E-print Network

Sulfates on Mars: A systematic Raman spectroscopic study of hydration states of magnesium sulfates of magnesium sulfates on the martian surface. In situ identification of the hydration states of magnesium of magnesium sulfate. Characteristic and distinct Raman spectral patterns were observed for each of the 11

270

Efflorescence as a source of hydrated sulfate minerals in valley settings on Mars  

NASA Astrophysics Data System (ADS)

A distinctive sulfur cycle dominates many geological processes on Mars and hydrated sulfate minerals are found in numerous topographic settings with widespread occurrences on the Martian surface. However, many of the key processes controlling the hydrological transport of sulfur, including sulfur sources, climate and the depositional history that led to precipitation of these minerals, remain unclear. In this paper, we use a model for the formation of sulfate efflorescent salts (Mg-Ca-Na sulfates) in the Rio Puerco watershed of New Mexico, a terrestrial analog site from the semiarid Southwest U.S., to assess the origin and environmental conditions that may have controlled deposition of hydrated sulfates in Valles Marineris on Mars. Our terrestrial geochemical results (?S34 of -36.0 to +11.1‰) show that an ephemeral arid hydrological cycle that mobilizes sulfur present in the bedrock as sulfides, sulfate minerals, and dry/wet atmospheric deposition can lead to widespread surface accumulations of hydrated sulfate efflorescences. Repeating cycles of salt dissolution and reprecipitation appear to be major processes that migrate sulfate efflorescences to sites of surface deposition and ultimately increase the aqueous SO42- flux along the watershed (average 41,273 metric tons/yr). We suggest that similar shallow processes may explain the occurrence of hydrated sulfates detected on the scarps and valley floors of Valles Marineris on Mars. Our estimates of salt mass and distribution are in accord with studies that suggest a rather short-lived process of sulfate formation (minimum rough estimate ?100 to 1000 years) and restriction by prevailing arid conditions on Mars.

Szynkiewicz, Anna; Borrok, David M.; Vaniman, David T.

2014-05-01

271

Reducing Phosphorus in Dairy Effluent Wastewater through Flocculation and Precipitation  

E-print Network

such as diallyl-dimethyl ammonium chloride (DADMAC) and polyacrylamide (PAM) are widely used in the treatment of wastewater. Use of 4 polymeric flocculants eliminates many of the undesirable consequences associated with use of aluminum sulfate (Rout et al... of the report as our flocculant. The flocculant was used to remove the organic particles from the effluent. Ammonium hydroxide was used to raise the pH of the effluent to facilitate precipitation of phosphates. Other bases could have been used...

Bragg, A.

2003-01-01

272

Conversion of alkali metal sulfate to the carbonate  

DOEpatents

A process for converting potassium sulfate to potassium carbonate in which a mixture of potassium sulfate and calcium oxide are reacted at a temperature in the range of between about 700.degree. C. and about 800.degree. C. with a gaseous mixture having a minor amount of hydrogen and/or carbon monoxide in a diluent with the calcium oxide being present in an amount not greater than about 20 percent by weight of the potassium sulfate to produce an aqueous mixture of potassium sulfide, potassium bisulfide, potassium hydroxide and calcium sulfide and a gaseous mixture of steam and hydrogen sulfide. The potassium and calcium salts are quenched to produce an aqueous slurry of soluble potassium salts and insoluble calcium salts and a gaseous mixture of steam and hydrogen sulfide. The insoluble calcium salts are then separated from the aqueous solution of soluble potassium salts. The calcium salts are dried to produce calcium sulfide, calcium bisulfide and steam, and then, the calcium sulfide and calcium bisulfide are converted to the oxide and recycled. The soluble potassium salts are carbonated to produce potassium carbonate which is concentrated and the precipitated crystals separated. The sulfur-containing compounds are further treated.

Sheth, Atul C. (Woodridge, IL)

1982-01-01

273

Crystallization of Chicken Egg White Lysozyme from Assorted Sulfate Salts  

NASA Technical Reports Server (NTRS)

Chicken egg white lysozyme has been found to crystallize from ammonium, sodium, potassium, rubidium, magnesium, and manganese sulfates at acidic and basic pH, with protein concentrations from 60 to 190 mg/ml. Four different crystal morphologies have been obtained, depending upon the temperature, protein concentration, and precipitating salt employed, Crystals grown at 15 C were generally tetragonal, with space group P43212. Crystallization at 20 C typically resulted in the formation of orthorhombic crystals, space group P21212 1. The tetragonal much less than orthorhombic morphology transition appeared to be a function of both the temperature and protein concentration, occurring between 15 and 20 C and between 100 and 125 mg/ml protein concentration. Crystallization from 0.8 -1.2M magnesium sulfate at pH 7.6 - 8.0 gave a hexagonal (trigonal) crystal form, space group P3121, which diffracted to 2.8 A. Ammonium sulfate was also found to result in a monoclinic form, space group C2. Small twinned monoclinic crystals of approx. 0.2 mm on edge were grown by dialysis followed by seeded sitting drop crystallization.

Forsythe, Elizabeth L.; Snell, Edward H.; Malone, Christine C.; Pusey, Marc L.

1998-01-01

274

Antarctic polar stratospheric aerosols: The roles of nitrates, chlorides and sulfates  

NASA Technical Reports Server (NTRS)

Nitric and hydrochloric acids have been postulated to condense in the winter polar stratosphere to become an important component of polar stratospheric clouds. One implication is that the removal of NO(y) from the gas phase by this mechanism allows high Cl(x) concentrations to react with O3, because the formation of ClNO3 is inhibited. Contributions of NO3 and Cl to the stratospheric aerosol were determined during the 1987 Airborne Antarctic Ozone Experiment by testing for the presence of nitrates and chlorides in the condensed phase. Aerosol particles were collected on four 500 micron diameter gold wires, each pretreated differently to give results that were specific to certain physical and chemical aerosol properties. One wire was carbon-coated for concentration and size analyses by scanning electron microscopy; X-ray energy dispersive analyses permitted the detection of S and Cl in individual particles. Three more wires were coated with Nitron, barium chloride and silver nitrate, respectively, to detect nitrate, sulfate and chloride in aerosol particles. All three ions, viz., sulfates, nitrates and chlorides were detected in the Antarctic stratospheric aerosol. In terms of number concentrations, the aerosol was dominated by sulfates, followed by chlorides and nitrates. An inverse linear regression can be established between nitrate concentrations and ozone mixing ratio, and between temperature and nitrates.

Pueschel, R. F.; Snetsinger, K. G.; Goodman, J. K.; Ferry, G. V.; Oberbeck, V. R.; Verma, S.; Fong, W.

1988-01-01

275

Changes in precipitation chemistry in Lithuania for 1981-2004.  

PubMed

This paper considers the spatial and temporal variability in concentrations of the potentially acidifying ions in precipitation in Lithuania during the 1981-2004 period. Chemical analysis of precipitation included measurements of pH, conductivity, sulfate (SO4(2-)), nitrate (NO3-), chloride (Cl-), ammonium (NH4+), sodium (Na+), potassium (K+), and calcium (Ca2+). Temporal trends in the potentially acidifying ion concentrations in precipitation and wet deposition were evaluated using the non-parametric Mann-Kendall test and Sen's slope estimator. A statistically significant decline was observed in non-sea salt sulfate (nssSO4(2-)) and hydrogen (H+) ions concentrations (82% and 79%, respectively) and wet depositions (88% and 74%, respectively). Temporal trends both in concentration and wet deposition of nitrate and ammonium were not as pronounced as trends in sulfate concentration. Analysis of air mass backward trajectories was applied to reveal the influence of air mass originating in different regions on wet deposition of acidifying species in Lithuania. Sector analysis clearly showed that wet deposition of sulfur and nitrogen in Lithuania is to a large extent anthropogenic and the main source regions of acidifying species contributing to wet deposition in Lithuania are in South and Central Europe. PMID:16528418

Sopauskiene, Dalia; Jasineviciene, Dalia

2006-03-01

276

Sulfates on Mars: Indicators of Aqueous Processes  

NASA Technical Reports Server (NTRS)

Recent analyses by MER instruments at Meridiani Planum and Gusev crater and the OMEGA instrument on Mars Express have provided detailed information about the presence of sulfates on Mars [1,2,3]. We are evaluating these recent data in an integrated multi-disciplinary study of visible-near-infrared, mid-IR and Mossbauer spectra of several sulfate minerals and sulfate-rich analog sites. Our analyses suggest that hydrated iron sulfates may account for features observed in Mossbauer and mid-IR spectra of Martian soils [4]. The sulfate minerals kieserite, gypsum and other hydrated sulfates have been identified in OMEGA spectra in the layered terrains in Valles Marineris and Terra Meridiani [2]. These recent discoveries emphasize the importance of studying sulfate minerals as tracers of aqueous processes. The sulfate-rich rock outcrops observed in Meridiani Planum may have formed in an acidic environment similar to acid rock drainage environments on Earth [5]. Because microorganisms typically are involved in the oxidation of sulfides to sulfates in terrestrial sites, sulfate-rich rock outcrops on Mars may be a good location to search for evidence of past life on that planet. Whether or not life evolved on Mars, following the trail of sulfate minerals will lead to a better understanding of aqueous processes and chemical weathering.

Bishop, Janice L.; Lane, Melissa D.; Dyar, M. Darby; Brown, Adrian J.

2006-01-01

277

Bioaccumulation of gold by sulfate-reducing bacteria cultured in the presence of gold(I)-thiosulfate complex  

Microsoft Academic Search

A sulfate-reducing bacterial (SRB) enrichment, from the Driefontein Consolidated Gold Mine, Witwatersrand Basin, Republic of South Africa, was able to destabilize gold(I)-thiosulfate complex (Au(S2O3)23-) and precipitate elemental gold. The precipitation of gold was observed in the presence of active (live) SRB due to the formation and release of hydrogen sulfide as an end-product of metabolism, and occurred by three possible

Maggy Lengke; Gordon Southam

2006-01-01

278

Amphorous hydrated Fe(III) sulfate: metastable product and bio-geochemical marker of iron oxidizing thiobacilli  

Microsoft Academic Search

Chemolithotrophic iron oxidation by Thiobacillus ferrooxidans and other iron oxidizing thiobacilli produce an Fe(III) sulfato complex that polymerizes as x-ray amorphous filaments approximately 40 nm in diameter. The precursor complex in solutionis seen by ATR-FTIR spectroscopy to have a sulfate spectrum resembling the v(subscript 3) and v(subscript 1) vibrational modes of the precipitated polymer. Chemically similar precipitates prepared by oxidation

Norman Lazaroff; John Jollie; Patrick R. Dugan

1998-01-01

279

Hydrazine sulfate: A current perspective  

Microsoft Academic Search

Hydrazine sulfate is an anticachexia agent which interrupts host energy wasting as a result of the malignant process. An inhibitor of gluconeogenesis at the phosphoenolpyruvate carboxykinase (PEP CK) reaction, this agent has been shown in randomized, placebo?controlled, double?blind trials to improve glucose tolerance, reduce glucose turnover, increase caloric intake, and increase or stabilize weight; in single?arm controlled trials, this agent

Joseph Gold

1987-01-01

280

Barium Titanate and Bismuth Oxide Nanocomposites Barium titanate, BaTiO3, and bismuth oxide Bi2O3 are transparent materials with  

E-print Network

(23), 5697 (2004). 22. "Comparative Study of Lead Borate and Bismuth Lead Borate Glass Systems as RadiationBarium Titanate and Bismuth Oxide Nanocomposites Barium titanate, BaTiO3, and bismuth oxide Bi2O3, Condensed Matter, Vol. 15, 8927 (2003). 21. "Highly Nonlinear Bismuth-Oxide Fiber for Smooth Supercontinuun

Harmon, Julie P.

281

Changing hafnium speciation in aqueous sulfate solutions: a high-energy X-ray scattering study.  

PubMed

The relationship of solution speciation and the structures of corresponding precipitates is examined for an aqueous Hf(4+) sulfate series. High-energy X-ray scattering (HEXS) and Raman spectroscopy data are used to probe atomic correlations in solutions. Hf(4+) in acidic perchlorate solution shows no evidence of a mononuclear metal species but instead has a peak in the pair-distribution function (PDF), generated from the HEXS data, at 3.55 Å, indicating Hf(4+)-Hf(4+) solution correlations. The peak intensity is consistent with clusters that are, on average, larger than the tetramic unit [M4(OH)8(H2O)16](8+) usually attributed to Zr(4+) and Hf(4+) solution speciation under these conditions. Addition of sulfate results in a breakup of hydroxo-bridged oligomers into sulfate-capped dimers and, for higher concentrations, Hf-sulfate monomers. The bidentate coordination mode of sulfate dominates the dissolved precursors, although it is not found in the structure of the final crystallized product, which instead is comprised of bridging-bidentate sulfate ligation. Neither the PDF patterns nor the Raman spectra show any evidence of the larger oligomers, such as the octadecameric metal clusters, found in similar Zr(4+) solutions. The oligomeric units found in solution provide insights into possible assembly routes for crystallization. In addition to expanding our understanding of synthesis science this study also reveals differences in the aqueous chemistries between Hf and Zr, two elements with ostensibly very similar chemical behavior. PMID:24871556

Kalaji, Ali; Skanthakumar, S; Kanatzidis, Mercouri G; Mitchell, John F; Soderholm, L

2014-06-16

282

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)

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).

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

1972-01-01

283

Cloud and Precipitation Radar  

NASA Astrophysics Data System (ADS)

Precipitation or weather radar is an essential tool for research, diagnosis, and nowcasting of precipitation events like fronts or thunderstorms. Only with weather radar is it possible to gain insights into the three-dimensional structure of thunderstorms and to investigate processes like hail formation or tornado genesis. A number of different radar products are available to analyze the structure, dynamics and microphysics of precipitation systems. Cloud radars use short wavelengths to enable detection of small ice particles or cloud droplets. Their applications differ from weather radar as they are mostly orientated vertically, where different retrieval techniques can be applied.

Hagen, Martin; Höller, Hartmut; Schmidt, Kersten

284

Pyroelectricity in alternating ultrathin organized molecular films incorporating barium ions  

NASA Astrophysics Data System (ADS)

Pyroelectric properties in alternating DAEP/NC Langmuir-Blodgett (LB) films and effects of incorporating the barium cations on pyroelectric behaviors have been investigated. Its pyroelectric coefficient measured is found to be 58?C m-2 K-1at 300K. The dielectric properties have been measured and used to determine the figures of merit in thermal devices. Relative permittivity ?r and dielectric loss values tan? of pyroelectric films (in the range of 1KHz - 100KHz) are 2.34~1.96 and 0.08~0.04, respectively. These data give a maximum pyroelectric figure of merit of 150?C m-2 K-1 in the alternating LB films incorporating barium ions. The effects of different deposition on pyroelectric properties are also discussed in this paper. It is indicated that the alternating LB films is promising in the field of pyroelectricity and pyroelectric infrared detector.

Ma, Shihong; Li, Shuhong; Lu, Xingze; Wang, Wencheng; Wang, Genshui; Liu, Pulin; Guo, Shaoling; Chu, Junhao

2002-12-01

285

Numerical simulation of a radially injected barium cloud  

NASA Technical Reports Server (NTRS)

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.

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

1981-01-01

286

Observations and theory of the AMPTE magnetotail barium releases  

NASA Technical Reports Server (NTRS)

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.

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

1987-01-01

287

Study of the photovoltaic effect in thin film barium titanate  

NASA Technical Reports Server (NTRS)

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.

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

1982-01-01

288

The crystal growth of barium flouride in aqueous solution  

NASA Astrophysics Data System (ADS)

The kinetics of growth of barium flouride seed crystals were investigated in aqueous solution at 25°C using a constant composition method, in which the supersaturation and ionic strength were maintained constant by the addition of titrants consisting of barium nitrate and potassium flouride solutions. The rates of reaction, studied over a range of supersaturation (? ? 0.4 to 1.0), were interpreted in terms of crystal growth models. A spiral growth mechanism best describes the data, and scanning electron microscopy indicates a three-dimensional growth. In the presence of inorganic additives such as phosphate, however, induction periods precede a morphological two-dimensional crystallization. Coulter Counter results show little crystal agglomeration.

Barone, J. P.; Svrjcek, D.; Nancollas, G. H.

1983-06-01

289

NASA/Max Planck Institute Barium Ion Cloud Project.  

NASA Technical Reports Server (NTRS)

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.

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

1973-01-01

290

Relationship of pheasant occurrence to barium in Illinois soils.  

PubMed

Distribution of the ring-necked pheasant (Phasianus colchicus) is nearly co-extensive with the boundary of Wisconsinan glaciation; this is an area of base-rich soils that are mostly developed in calcareous tills. Anderson and Stewart (1973) speculated that barium in the diet might be a factor limiting the pheasant establishment in habitats adjacent to areas of long-term sustaining populations in Illinois. Total Ba was calculated for soils of 74 conterminous counties for which there were pheasant population data. Barium over the range of about 480 to 700 mg kg(-1) soil was unrelated to pheasant occurrence or to population indeces. The selective eating of iron-manganese concretions that are enriched in Ba might present a unique pathway for Ba loading. PMID:24197899

Jones, R L

1992-04-01

291

The Skylab barium plasma injection experiments. I - Convection observations  

NASA Technical Reports Server (NTRS)

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.

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

1976-01-01

292

Isotopic Masses of Hydrogen, Chlorine, Barium, Cerium, and Neodymium  

Microsoft Academic Search

The 16-in. double-focusing mass spectrometer at the University of Minnesota has been employed to measure the atomic mass of H1 and the atomic masses and isotopic mass differences of chlorine, barium, cerium, and neodymium. Recent improvements in instrumentation have increased the precision of both narrow and wide doublet measurements. The doublet C11H22-C12H10 was used to relate the H1 mass directly

Jay L. Benson; Walter H. Johnson

1966-01-01

293

Photoionization of the 4d subshell of barium  

Microsoft Academic Search

The photoionization cross section and angular distribution asymmetry parameter of the 4d10 subshell of atomic barium have been calculated using many-body perturbation theory and the relativistic random-phase approximation modified to include relaxation effects. Our main purpose is to determine whether relaxation and polarization effects can account for the large difference between recent 4d photoemission experiments and total absorption experiments. Polarization

M Kutzner; V Radojevi?; H P Kelly; Z Altun

1990-01-01

294

Photoionization of atomic barium including effects of relaxation and polarization  

Microsoft Academic Search

The photoionization cross sections of the 4d10, 5s2, 5p6, and 6s2 subshells of atomic barium and the angular distribution asymmetry parameters for the 4d10 and 5p6 subshells have been calculated using many-body perturbation theory. Our main purpose is to determine whether relaxation and polarization effects can account for the large difference between recent 4d photoemission experiments and total absorption experiments.

Mickey Kutzner; Zikri Altun; Hugh P. Kelly

1990-01-01

295

Domain Size Effect on Dielectric Properties of Barium Titanate Ceramics  

Microsoft Academic Search

Barium titanate (BaTiO3) ceramics with various grain sizes were prepared by a conventional sintering method and a two-step sintering method. The permittivity of the ceramics increased with decreasing the grain size down to 1.1 mum on average. The BaTiO3 ceramics with an average grain size of 1.1 mum had a high permittivity of 7,700. The transmission electron microscopy (TEM) observation

Takuya Hoshina; Kayo Takizawa; Jianyong Li; Takeshi Kasama; Hirofumi Kakemoto; Takaaki Tsurumi

2008-01-01

296

Ultrasonic Investigation on Nanocrystalline Barium Borate (BBO) Glass Ceramics  

Microsoft Academic Search

Barium Borate (BBO) glasses containing different compositions of BaO and B2O3 with BaF2, Cr2O3 and TiO2 have been prepared by normal melting and annealing technique. The prepared bulk BBO glasses have been subjected to heat?treatment. The heat?treated BBO glasses produce nanophase BBO crystals in its structure. The existence of nanophase structure of the BBO crystals have been studied through XRD

A. V. Gayathri Devi; V. Rajendran; K. Jeyasubramanian; N. Suresh Kumar

2006-01-01

297

Negative-U extended Hubbard model for doped barium bismuthates  

Microsoft Academic Search

We present detailed mean-field and random-phase-approximation studies of the negative-U, extended Hubbard model with a view to understanding the properties of the doped barium bismuthates. In particular, we obtain the phase diagram, the excitation spectrum, and the optical conductivity in the semiconducting phase of the bismuthates. We show by explicit calculations how this model leads to a natural explanation for

A. Taraphder; H. R. Krishnamurthy; Rahul Pandit; T. V. Ramakrishnan

1995-01-01

298

Light yield and surface treatment of barium fluoride crystals  

Microsoft Academic Search

We report on a study of the light yield and surface treatment of barium fluoride (BaF2) scintillation crystals. Using a bialkali photocathode the photoelectron (p.e.) yield of BaF2 crystals was measured to be 130 p.e.\\/MeV for the fast components and 700 p.e.\\/MeV for the slow component. A somewhat hygroscopic nature for the BaF2 is found. Teflon film was found to

Z. Y. Wei; R. Y. Zhu; H. Newman; Z. W. Yin

1991-01-01

299

Elastic and Piezoelectric Coefficients of Single-Crystal Barium Titanate  

Microsoft Academic Search

Mechanical resonance and antiresonance frequencies were measured on barium titanate single-crystal elements maintained under electric dc bias from -50°C to +150°C. A complete set of elastic, piezoelectric, and dielectric constants of the tetragonal modification at 25°C is obtained. The elastic compliances show substantial deviation from cubic symmetry. Measurements in the orthorhombic state show longitudinal compliance four times higher than in

Don Berlincourt; Hans Jaffe

1958-01-01

300

Adequacy of preparation for barium enema among elderly outpatients.  

PubMed Central

OBJECTIVE: To determine whether outpatients 75 years of age or older have a higher rate of inadequate bowel preparation for barium enema and of complications associated with the preparation and the test than patients aged 55 to 74 years. DESIGN: Cross-sectional survey. SETTING: Radiology department in a teaching hospital. PATIENTS: Patients 55 years or older referred for a barium enema from March to August 1988. OUTCOME MEASURES: All films were reviewed independently by a study radiologist blind to the staff radiologist's report. Patients were interviewed by telephone within several days after the test to assess the occurrence of problems during the preparation or the test. MAIN RESULTS: Of the 213 patients assessed 72 were excluded: 43 refused to participate or could not be contacted, 16 had previously undergone colonic surgery, and 13 were excluded for other reasons. The remaining 141 patients were separated into three age groups: those 55 to 64 years (46 patients), those 65 to 74 (47) and those 75 or older (48). In 104 cases (74%) the bowel had been prepared adequately; there was no significant difference between the three groups with regard to the adequacy of preparation. The incidence of problems reported by the patients did not differ significantly between the groups. CONCLUSIONS: Outpatients aged 75 years or more are no more likely than those aged 55 to 74 to have problems with bowel preparation or the barium enema itself. Age should not be a criterion for exclusion from barium enema. To try to lower the rate of poor bowel preparation clinicians and radiologists should consider counselling patients more carefully about the importance of proper preparation. Also, the current method of preparation could be examined to determine whether simple changes would significantly improve colon cleanliness. PMID:2025821

Grad, R M; Clarfield, A M; Rosenbloom, M; Perrone, M

1991-01-01

301

Acute barium intoxication following ingestion of soap water solution  

PubMed Central

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

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

2012-01-01

302

Radium and barium in the Amazon River system  

Microsoft Academic Search

Data for ²²⁶Ra and ²²⁸Ra 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

Willard S. Moore; John M. Edmond

1984-01-01

303

Relationship of pheasant occurrence to barium in Illinois soils  

Microsoft Academic Search

Distribution of the ring-necked pheasant (Phasianus colchicus) is nearly co-extensive with the boundary of Wisconsinan glaciation; this is an area of base-rich soils that are mostly developed in calcareous tills. Anderson and Stewart (1973) speculated that barium in the diet might be a factor limiting the pheasant establishment in habitats adjacent to areas of long-term sustaining populations in Illinois. Total

Robert L. Jones

1992-01-01

304

Synthesis of YAG:Ce phosphor via different aluminum sources and precipitation processes  

Microsoft Academic Search

Ce3+-doped yttrium aluminum garnet (YAG:Ce) phosphors were synthesized by the four different precipitating processes, in which aluminum nitrate or aluminum ammonium sulfate was used as the aluminum source. Pure YAG:Ce powder can be obtained by using aluminum nitrate combine normal strike precipitation method as calcined at 850°C for 2h. The property of YAG powder is affected by the cation homogeneity

C. C. Chiang; M. S. Tsai; C. S. Hsiao; M. H. Hon

2006-01-01

305

Chemoenzymatic synthesis of heparan sulfate and heparin.  

PubMed

Covering: up to May 2014Heparan sulfate is a polysaccharide that plays essential physiological functions in the animal kingdom. Heparin, a highly sulfated form of heparan sulfate, is a widely prescribed anticoagulant drug worldwide. The heparan sulfate and heparin isolated from natural sources are highly heterogeneous mixtures differing in their polysaccharide chain lengths and sulfation patterns. The access to structurally defined heparan sulfate and heparin is critical to probe the contribution of specific sulfated saccharide structures to the biological functions as well as for the development of the next generation of heparin-based anticoagulant drugs. The synthesis of heparan sulfate and heparin, using a purely chemical approach, has proven extremely difficult, especially for targets larger than octasaccharides having a high degree of site-specific sulfation. A new chemoenzymatic method has emerged as an effective alternative approach. This method uses recombinant heparan sulfate biosynthetic enzymes combined with unnatural uridine diphosphate-monosaccharide donors. Recent examples demonstrate the successful synthesis of ultra-low molecular weight heparin, low-molecular weight heparin and bioengineered heparin with unprecedented efficiency. The new method provides an opportunity to develop improved heparin-based therapeutics. PMID:25197032

Liu, Jian; Linhardt, Robert J

2014-12-01

306

Internal hemorrhoids: diagnosis with double-contrast barium enema examinations.  

PubMed

The authors retrospectively studied 43 patients suspected of having internal hemorrhoids at double-contrast barium enema examination. At endoscopy, 24 patients (56%) had internal hemorrhoids, four (9%) had other pathologic lesions in the rectum without evidence of hemorrhoids, and 15 (35%) had no reported abnormalities in the rectum. Internal hemorrhoids were found at endoscopy in 10 of 20 patients (50%) with lobulated folds extending 3 cm or less from the anorectal junction and 10 of 13 patients (77%) with multiple submucosal nodules. However, no patients with these characteristic radiographic findings were found to have other pathologic lesions in the rectum that had been mistaken for hemorrhoids at barium enema examination. Conversely, three of four patients with lobulated folds extending more than 3 cm from the anorectal junction and one of six patients with solitary nodules had proctitis or rectal neoplasms. Thus, specific criteria are suggested for the diagnosis of internal hemorrhoids on double-contrast barium enema examinations. Suspected hemorrhoids that do not fulfill these criteria should be evaluated endoscopically to rule out other more serious pathologic lesions in the rectum. PMID:2399313

Levine, M S; Kam, L W; Rubesin, S E; Ekberg, O

1990-10-01

307

Chemisorption And Precipitation Reactions  

EPA Science Inventory

The transport and bioavailability of chemical components within soils is, in part, controlled by partitioning between solids and solution. General terms used to describe these partitioning reactions include chemisorption and precipitation. Chemisorption is inclusive of the suit...

308

Quantitative Precipitation Forecasting Overview  

NSDL National Science Digital Library

In this module, Wes Junker, retired Senior Branch Forecaster at NCEP/HPC provides an introduction to Quantitative Precipitation Forecasting. This presentation assumes a familiarity with basic meteorological processes.

Comet

2007-11-01

309

Macrophage secretory products selectively stimulate dermatan sulfate proteoglycan production in cultured arterial smooth muscle cells  

SciTech Connect

Arterial dermatan sulfate proteoglycan has been shown to increase with atherosclerosis progression, but factors responsible for this increase are unknown. To test the hypothesis that smooth muscle cell proteoglycan synthesis may be modified by macrophage products, pigeon arterial smooth muscle cells were exposed to the media of either cholesteryl ester-loaded pigeon peritoneal macrophages or a macrophage cell line P388D1. Proteoglycans radiolabeled with (35S)sulfate and (3H)serine were isolated from culture media and smooth muscle cells and purified following precipitation with 1-hexadecylpyridinium chloride and chromatography. Increasing concentrations of macrophage-conditioned media were associated with a dose-response increase in (35S)sulfate incorporation into secreted proteoglycans, but there was no change in cell-associated proteoglycans. Incorporation of (3H)serine into total proteoglycan core proteins was not significantly different (5.2 X 10(5) dpm and 5.5 X 10(5) disintegrations per minute (dpm) in control and conditioned media-treated cultures, respectively), but selective effects were observed on individual proteoglycan types. Twofold increases in dermatan sulfate proteoglycan and limited degradation of chondroitin sulfate proteoglycan were apparent based on core proteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Immunoinhibition studies indicated that interleukin-1 was involved in the modulation of proteoglycan synthesis by macrophage-conditioned media. These data provide support for the role of macrophages in alteration of the matrix proteoglycans synthesized by smooth muscle cells and provide a mechanism to account for the reported increased dermatan sulfate/chondroitin sulfate ratios in the developing atherosclerotic lesion.

Edwards, I.J.; Wagner, W.D.; Owens, R.T. (Wake Forest Univ., Winston-Salem, NC (USA))

1990-03-01

310

Inhibition of synthesis of heparan sulfate by selenate: Possible dependence on sulfation for chain polymerization  

SciTech Connect

Selenate, a sulfation inhibitor, blocks the synthesis of heparan sulfate and chondroitin sulfate by cultured endothelial cells. In contrast, selenate does not affect the production of hyaluronic acid, a nonsulfated glycosaminoglycan. No differences in molecular weight, ({sup 3}H)glucosamine/({sup 35}S)sulfuric acid ratios, or disaccharide composition were observed when the heparan sulfate synthesized by selenate-treated cells was compared with that of control cells. The absence of undersulfated chains in preparations from cultures exposed to selenate supports the concept that, in the intact cell, the polymerization of heparan sulfate might be dependent on the sulfation of the saccharide units added to the growing glycosaminoglycan chain.

Dietrich, C.P.; Nader, H.B. (Paulist School of Medicine, Sao Paulo (Brazil)); Buonassisi, V.; Colburn, P. (W. Alton Jones Cell Science Center, Lake Placid, NY (USA))

1988-01-01

311

Absorbing properties and structural design of microwave absorbers based on carbonyl iron and barium ferrite  

Microsoft Academic Search

Carbonyl iron and barium ferrite powder (BaZn1.5Co0.5Fe16O27) were prepared in this work. The complex permittivity and permeability spectra for rubber radar absorbing materials employing carbonyl iron and barium ferrite powders were measured. A database describing the frequency dependence of the permittivities and permeabilities of the carbonyl iron and barium ferrite microwave absorbers with various powder percentage compositions in 2 18

Y. B. Feng; T. Qiu; C. Y. Shen

2007-01-01

312

Absorbing properties and structural design of microwave absorbers based on carbonyl iron and barium ferrite  

Microsoft Academic Search

Carbonyl iron and barium ferrite powder (BaZn1.5Co0.5Fe16O27) were prepared in this work. The complex permittivity and permeability spectra for rubber radar absorbing materials employing carbonyl iron and barium ferrite powders were measured. A database describing the frequency dependence of the permittivities and permeabilities of the carbonyl iron and barium ferrite microwave absorbers with various powder percentage compositions in 2–18GHz was

Y. B. Feng; T. Qiu; C. Y. Shen

2007-01-01

313

CORRECTING RADM'S SULFATE UNDERPREDICTION: DISCOVERY AND CORRECTION OF MODEL ERRORS AND TESTING THE CORRECTIONS THROUGH COMPARISONS AGAINST FIELD DATA  

EPA Science Inventory

A serious underprediction of ambient sulfate (SO2-4) by two comprehensive, Eulerian models of acid deposition, the Regional Acid Deposition Model (RADM) and the Acid Deposition and Oxidant Model (ADOM), was found in the National Acid Precipitation Assessment Program phase of the ...

314

The influence of cut off lows on sulfate burdens over the North Atlantic during April, 1987  

SciTech Connect

The authors have presented examples from a modeling study of the development of sulfur burdens over North America, the North Atlantic Ocean and Europe during April, 1987 using observation-derived meteorological data to represent the actual conditions for this period, focusing on the influence of cut-off lows on SO{sub 2} and sulfate column burdens over the North Atlantic Ocean. The analysis demonstrates that these systems can serve either as sources or sinks of sulfate, and that the major factor governing their resulting effect is the position during its formative stages relative to (a) sources of moisture, and (b) sulfur emissions, which regulates the availability of sulfur, cloud liquid water for sulfur oxidation, and the amount of precipitation for sulfate removal produced in the later stages of the life cycle.

Benkovitz, C.M.; Miller, M.A.; Schwartz, S.E.; Kwon, O.U.

2001-01-14

315

Mechanism of action of barium ion on rat aortic smooth muscle.  

PubMed

The mechanism of action of barium ion on the aortic smooth muscle of the normal rat was investigated using in vitro calcium-depleted aortic strips. Aortic strips were depleted of calcium by repeated exposure to norepinephrine in a calcium-free bathing solution. Although calcium depletion abrogated the response of strips to catecholamines and depolarizing agents, the response to barium chloride remained quantitatively intact. The calcium influx blocker D 600 prevented the contractile response to barium but not to catecholamines, whereas phentolamine prevented the response to catecholamines but not barium. The strip response to barium was depressed by a twofold increase in extracellular magnesium concentration whether the strip was intact or calcium depleted. Although increased concentrations of calcium in the extracellular medium inhibited the contractile response to potassium ion, increases in barium merely potentiated the potassium contracture. These findings indicate that barium produces its contractile effect on vascular smooth muscle by a direct intracellular interaction with the contractile or regulatory proteins. Barium enters these cells via calcium influx channels and is probably not sequestered in a physiologically releasable pool. Unlike calcium, barium does not stabilize the smooth muscle sarcolemma when present in high concentration. PMID:6703038

Hansen, T R; Dineen, D X; Petrak, R

1984-03-01

316

Sulfate reduction in freshwater wetland soils and the effects of sulfate and substrate loading  

SciTech Connect

Elevated sulfate and organic C loadings in freshwater wetlands could stimulate dissimilatory sulfate reduction that oxidizes organic C, produces hydrogen sulfide and alkalinity, and sequesters trace metals. The authors determined the extent of sulfate reduction in two freshwater wetland soils, that is black gum (Nyssa biflona) swamp soils and titi (Cliftonia monophylla) swamp soils, in northern Florida. They also investigated the potential of sulfate reduction in the wetland soils by adding sulfate, organic substrate, and lime. Sulfate reduction was found to be an active process in both swamp soils without any amendment, where the pore water pH was as low as 3.6 and sulfate concentration was as low as 5 mg L{sup {minus}1}. Without amendment, 11 to 14% of organic C was oxidized through sulfate reduction in the swamp soils. Sulfate loading, liming, and substrate addition significantly increased sulfate reduction in the black gum swamp soil, but none of those treatments increase sulfate reduction in the titi swamp soil. The limiting factor for sulfate reduction in the titi swamp soil were likely texture and soil aggregate related properties. The results suggested that wastewater loading may increase sulfate reduction in some freshwater wetlands such as the black swamps while it has no stimulating effect on other wetlands such as the titi swamps.

Feng, J.; Hsieh, Y.P. [Florida A and M Univ., Tallahassee, FL (United States)

1998-07-01

317

Linking Microbial Ecology to Geochemistry in Sulfate Reducing Systems  

NASA Astrophysics Data System (ADS)

Sulfate reducing bioreactors (SRBRs) can serve as passive treatment systems for mining influenced waters (MIW). An enhanced understanding of the biogeochemistry and efficacy of SRBRs can be achieved by combining molecular biological and geochemical techniques in both field and column settings. To this end, a spatial and temporal sequence of eight pilot-scale columns were analyzed employing a multidisciplinary approach using ICP-AES, next-generation sequencing, and SEM-EDX to explore the effects of variable substrate on community structure and performance (measured by Zn removal). All pilot scale reactors contained 30% limestone by mass, 7 of the 8 had variable amounts of woodchips, sawdust, and alfalfa hay, and an 8th column where the only carbon source was walnut shells. High throughput sequencing of DNA extracted from liquid in pilot-scale columns reveals, similarly to an analogous field system in Arizona, a dominance of Proteobacteria. However, after the first pore volume, performance differences between substrate permutations emerged, where columns containing exclusively walnut shells or sawdust exhibited a more effective startup and metal removal than did columns containing exclusively woodchips or alfalfa hay. SEM-EDX analysis revealed the initial formation of gypsum (CaSO4) precipitates regardless of substrate. Zn was observed in the presence of Ca, S, and O in some column samples, suggesting there was co-precipitation of Zn and CaSO4. This is congruent with micro-XAS analysis of field data suggesting iron sulfides were co-precipitating with gypsum. A SEM-EDX analysis from a subsequent sampling event (8 months into operation) indicated that precipitation may be shifting to ZnS and ZnCO3. Biplots employing Canonical Correspondence Analysis (CCA) describe how diversity scales with performance and substrate selection, and how community shifts may result in differential performance and precipitation in response to selective pressure of bioreactor material on community composition. CCA of Shannon diversity data after one pore volume revealed that zinc removal, walnut shell content, and abundance of delta-Proteobacteria (sulfate reducing organisms) were all corresponding elements. However, after several pore volumes, the walnut shell column was no longer removing Zn as effectively, and community shifts were observed throughout the columns. Analysis of field and laboratory scale microbiological and geochemical shifts, in parallel, gives insight into key biogeochemical variables linked to the performance of passive remediation systems used for the treatment of contaminated MIW, while also providing further insight into metal immobilization at the microbe-mineral interface.

Drennan, D. M.; Lee, I.; Landkamer, L.; Almstrand, R.; Figueroa, L. A.; Sharp, J. H.

2013-12-01

318

Solar-thermal decomposition of zinc sulfate  

NASA Astrophysics Data System (ADS)

Experimental decomposition of zinc sulfate in a rotary kiln which was heated in the White Sands Solar Furnace is described. The main findings are: the zinc sulfate sulfate decomposed after 1 to 5 minutes of solar exposure when the front thermocouple indicated 7000 C and kiln was being rapidly heated with a flux of 9 to 14 kW; or the front thermocouple was above 8500 C and the kiln was maintained at temperature with a minimal flux. It is found that there is a problem with zinc sulfate agglomeration above approximately 8000 C. The agglomeration problem interfered significantly with testing, and it prevented the acquisition of quantitative data on the rate and extent of zinc sulfate decomposition. The agglomeration problem solved either by physically breaking apart the agglomerate by chains or by mixing inert compounds with the zinc sulfate to prevent the particles from sticking to each other. The rotary kiln performed satisfactorily and there were no problems with the window.

Shell, P. K.; Ruiz, R.; Yu, C. M.

1983-01-01

319

Depolymerization of sulfated polysaccharides under hydrothermal conditions.  

PubMed

Fucoidan and chondroitin sulfate, which are well known sulfated polysaccharides, were depolymerized under hydrothermal conditions (120-180°C, 5-60min) as a method for the preparation of sulfated polysaccharides with controlled molecular weights. Fucoidan was easily depolymerized, and the change of the molecular weight values depended on the reaction temperature and time. The degree of sulfation and IR spectra of the depolymerized fucoidan did not change compared with those of untreated fucoidan at reaction temperatures below 140°C. However, fucoidan was partially degraded during depolymerization above 160°C. Nearly the same depolymerization was observed for chondroitin sulfate. These results indicate that hydrothermal treatment is applicable for the depolymerization of sulfated polysaccharides, and that low molecular weight products without desulfation and deformation of the initial glycan structures can be obtained under mild hydrothermal conditions. PMID:24361592

Morimoto, Minoru; Takatori, Masaki; Hayashi, Tetsuya; Mori, Daiki; Takashima, Osamu; Yoshida, Shinichi; Sato, Kimihiko; Kawamoto, Hitoshi; Tamura, Jun-ichi; Izawa, Hironori; Ifuku, Shinsuke; Saimoto, Hiroyuki

2014-01-30

320

Protein sulfation analysis--A primer.  

PubMed

The aim of this review is to present an overview of protein sulfation in the context of 'modificomics', i.e. post-translational modification-specific proteome research. In addition to a short introduction to the biology of protein sulfation (part 1), we will provide detailed discussion regarding (i) methods and tools for prediction of protein tyrosine sulfation sites (part 2), (ii) biochemical techniques used for protein sulfation analysis (part 3.1), and (iii) mass spectrometric strategies and methods applied to protein sulfation analysis (part 3.2). We will highlight strengths and limitations of different strategies and approaches (including references), providing a primer for newcomers to protein sulfation analysis. PMID:16952486

Monigatti, Flavio; Hekking, Brian; Steen, Hanno

2006-12-01

321

Semi-synthesis of chondroitin sulfate-E from chondroitin sulfate-A  

PubMed Central

Chondroitin sulfate-E (chondroitin-4, 6-disulfate) was prepared from chondroitin sulfate-A (chondroitin-4 - sulfate) by regioselective sulfonation, performed using trimethylamine sulfur trioxide in formamide under argon. The structure of semi-synthetic chondroitin sulfate-E was analyzed by PAGE, 1H NMR, 13C NMR, 2D NMR and disaccharide analysis and compared with natural chondroitin sulfate-E. Both semi-synthetic and natural chondroitin sulfate-E were each biotinylated and immobilized on BIAcore SA biochips and their interactions with fibroblast growth factors displayed very similar binding kinetics and binding affinities. The current semi-synthesis offers an economical approach for the preparation of the rare chondroitin sulfate-E from the readily available chondroitin sulfate-A. PMID:22140285

Cai, Chao; Solakyildirim, Kemal; Yang, Bo; Beaudet, Julie M.; Weyer, Amanda; Linhardt, Robert J.; Zhang, Fuming

2011-01-01

322

Recovery of Kraft Lignin from Aqueous Solutions with Oxotitanium Sulfate, Aluminum Sulfate, and Their Mixture  

Microsoft Academic Search

Coagulation recovery of kraft lignin from aqueous solutions with oxotitanium sulfate, aluminum sulfate, and a composite coagulant based on their mixture was studied in a wide range of coagulant concentrations and solution pH values.

Yu. M. Chernoberezhskii; D. Yu. Mineev; A. B. Dyagileva; A. V. Lorentsson; Yu. V. Belova

2002-01-01

323

Fluidized Bed Selective Oxidation-Sulfation Roasting of Nickel Sulfide Concentrate: Part II. Sulfation Roasting  

NASA Astrophysics Data System (ADS)

The fluidized bed sulfation roasting process followed by water leaching was investigated as an alternative process to treat nickel sulfide concentrate for nickel production. The effects of several roasting parameters, such as the sulfation gas flow rate, roasting temperature, the addition of Na2SO4, and the roasting time, were studied. 79 pct Ni, 91 pct Cu, and 95 pct Co could be recovered with minimal dissolution of Fe of 4 pct by water leaching after two-stage oxidation-sulfation roasting under optimized conditions. The sulfation roasting mechanism was investigated, showing that the outermost layer of sulfate melt and the porous iron oxide layer create a favorable sulfation environment with high partial pressure of SO3. Sulfation of the sulfide core was accompanied by the conversion of the sulfide from Ni1- x S to Ni7S6 as well as inward diffusion of the sulfation gas.

Yu, Dawei; Utigard, Torstein A.; Barati, Mansoor

2014-04-01

324

Inhibiting sulfate-reducing bacteria in biofilms on steel with antimicrobial peptides generated in situ  

Microsoft Academic Search

In batch and continuous fermentations, the reduction in corrosion of SAE 1018 mild steel and 304 stainless steel caused by\\u000a inhibition of the reference sulfate-reducing bacterium (SRB) Desulfovibrio vulgaris by a protective, antimicrobial-producing Bacillus brevis biofilm was investigated. The presence of D. vulgaris produced a thick black precipitate on mild steel and a higher corrosion rate in batch cultures than

A. Jayaraman; P. J. Hallock; R. M. Carson; C.-C. Lee; F. B. Mansfeld; T. K. Wood

1999-01-01

325

Modeling in-situ uranium(VI) bioreduction by sulfate-reducing bacteria  

Microsoft Academic Search

We present a travel-time based reactive transport model to simulate an in-situ bioremediation experiment for demonstrating enhanced bioreduction of uranium(VI). The model considers aquatic equilibrium chemistry of uranium and other groundwater constituents, uranium sorption and precipitation, and the microbial reduction of nitrate, sulfate and U(VI). Kinetic sorption\\/desorption of U(VI) is characterized by mass transfer between stagnant micro-pores and mobile flow

Jian Luo; Frank-Andreas Weber; Olaf A. Cirpka; Wei-Min Wu; Jennifer L. Nyman; Jack Carley; Philip M. Jardine; Craig S. Criddle; Peter K. Kitanidis

2007-01-01

326

Sulfate aerosol and climatic change  

SciTech Connect

The predicted Earth warming based on recent increases in concentrations of greenhouse gases is slightly more than the observed warming of the atmosphere. In addition, the warming trend in North America does not appear to follow the global pattern. What might account for these and other deviations of fact from theory The answer is ironic. In all probability, aerosols primarily composed of sulfates, themselves the result of commercial activity, enhance the ability of the atmosphere to reflect sunlight back into space before it can reach the planet's surface and participate in the warming process. The sulfate particles, about 0.1 to one micron in diameter, are particularly concentrated over the industrial area of the Northern Hemisphere. Their capacity to cool by scattering sunlight has become a recognized force in climatic change only recently. Clearly, both the cooling effects of aerosols and the warming caused by greenhouse gases must be taken into account if we are to attain accurate climate models and effective industrial policies. 4 refs., 6 figs.

Charlson, R.J. (Univ. of Washington, WA (United States)); Wigley, T.M.L. (University Corporation for Atmospheric Research, Boulder, CO (United States))

1994-02-01

327

Changes in vascular pattern of chicken chorioallantois after cartilaginous extract, chondroitin sulfate and dextran sulfate treatment.  

PubMed

Cartilaginous extract, chondroitin sulfate C as well as dextran sulfate in gelatin pellets have an inhibitory effect on the development of fine capillaries, in contrast to pure gelatin pellets or pellets with sucrose. These results suggest an unspecific inhibitory effect of anionic saccharidic polymers on the development of chorioallantoic membrane vessels, because the chemical structure of dextran sulfate is (except anionic groups) different from chondroitin sulfate in the pure form or in the form of proteoglycans (in cartilaginous extract). PMID:8348985

Klepácek, I; Smetana, K; Stol, M

1993-01-01

328

ASSESSING MINE DRAINAGE WATER QUALITY FROM THE COLOR AND SPECTRAL REFLECTANCE OF CHEMICAL PRECIPITATES  

EPA Science Inventory

The pH and dissolved sulfate concentrations of mine impacted waters were estimated on the basis of the spectral reflectance of resident sediments composed mostly of chemical precipitates. Mine drainage sediments were collected from sites in the Anthracite Region of eastern Pe...

329

Iron Oxidation and Precipitation of Ferric Hydroxysulfates by Resting Thiobacillus ferrooxidans Cells.  

PubMed

The oxidation of ferrous ions, in acid solution, by resting suspensions of Thiobacillus ferrooxidans produced sediments consisting of crystalline jarosites, amorphous ferric hydroxysulfates, or both. These products differed conspicuously in chemical composition and infrared spectra from precipitates formed by abiotic oxidation under similar conditions. The amorphous sediments, produced by bacterial oxidation, exhibited a distinctive fibroporous microstructure when examined by scanning electron microscopy. Infrared spectra indicated outer-sphere coordination of Fe(III) by sulfate ions, as well as inner-sphere coordination by water molecules and bridging hydroxo groups. In the presence of excess sulfate and appropriate monovalent cations, jarosites, instead of amorphous ferric hydroxysulfates, precipitated from bacterially oxidized iron solutions. It is proposed that the jarositic precipitates result from the conversion of outer-sphere (T(d)) sulfate, present in a soluble polymeric Fe(III) complex, to inner-sphere (C(3v)) bridging sulfate. The amorphous precipitates result from the further polymerization of hydroxo-linked iron octahedra and charge stabilized aggregation of the resulting iron complexes in solution. This view was supported by observations that bacterially oxidized iron solutions gave rise to either amorphous or jarositic sediments in response to ionic environments imposed after oxidation had been completed and the bacteria had been removed by filtration. PMID:16345996

Lazaroff, N; Sigal, W; Wasserman, A

1982-04-01

330

Iron Oxidation and Precipitation of Ferric Hydroxysulfates by Resting Thiobacillus ferrooxidans Cells  

PubMed Central

The oxidation of ferrous ions, in acid solution, by resting suspensions of Thiobacillus ferrooxidans produced sediments consisting of crystalline jarosites, amorphous ferric hydroxysulfates, or both. These products differed conspicuously in chemical composition and infrared spectra from precipitates formed by abiotic oxidation under similar conditions. The amorphous sediments, produced by bacterial oxidation, exhibited a distinctive fibroporous microstructure when examined by scanning electron microscopy. Infrared spectra indicated outer-sphere coordination of Fe(III) by sulfate ions, as well as inner-sphere coordination by water molecules and bridging hydroxo groups. In the presence of excess sulfate and appropriate monovalent cations, jarosites, instead of amorphous ferric hydroxysulfates, precipitated from bacterially oxidized iron solutions. It is proposed that the jarositic precipitates result from the conversion of outer-sphere (Td) sulfate, present in a soluble polymeric Fe(III) complex, to inner-sphere (C3v) bridging sulfate. The amorphous precipitates result from the further polymerization of hydroxo-linked iron octahedra and charge stabilized aggregation of the resulting iron complexes in solution. This view was supported by observations that bacterially oxidized iron solutions gave rise to either amorphous or jarositic sediments in response to ionic environments imposed after oxidation had been completed and the bacteria had been removed by filtration. Images PMID:16345996

Lazaroff, Norman; Sigal, Warren; Wasserman, Andrew

1982-01-01

331

ACID PRECIPITATION PATTERNS AND TRENDS IN EASTERN NORTH AMERICA, 1980-1984  

EPA Science Inventory

Using data compiled from seven nationwide precipitation chemistry networks in the U.S. and Canada, the spatial distribution of hydrogen, sulfate, and nitrate ions in North America is discussed. eographic patterns of concentration and deposition are characterized using isopleth ma...

332

Chemical composition of precipitation and its sources in Hangzhou, China.  

PubMed

To understand the origin and chemical characteristics of precipitation in Hangzhou, rainwater samples were collected from June 2006 to May 2008. All samples were analyzed for pH, electrical conductivity, and major ions (NH??, Ca²?, Mg²?, Na?, K?, SO?²?, NO??, F?, and Cl?). Acidification of precipitation in Hangzhou was serious with volume-weighted mean pH value of 4.5, while frequency of acid rain was 95%. The calculated SO?²?/NO?? ratio in Hangzhou precipitation was 2.87, which indicated that the precipitation of Hangzhou belonged to sulfate-based acid rain. The results of acid neutralization analysis showed that not all the acidity in the precipitation of Hangzhou was neutralized by alkaline constituents. The results of sea salt contribution analysis showed that nearly all SO?²?, Ca²?, and Mg²? and 33.7% of K? were of non-sea origins, while all Na? and Cl? and 66.3% of K? originated from sea sources. The principal component analysis which was used to analyze the sources of various ions indicated that chemical compositions of precipitation in Hangzhou mainly came from terrestrial sources, factory emissions, fuel wood burning, and marine sources. PMID:21380918

Xu, Hong; Bi, Xiao-Hui; Feng, Yin-Chang; Lin, Feng-Mei; Jiao, Li; Hong, Sheng-Mao; Liu, Wen-Gao; Zhang, Xiao-Yong

2011-12-01

333

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

PubMed

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. PMID:24844320

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

2014-08-01

334

Kinetic comparison of microbial assemblages for the anaerobic treatment of wastewater with high sulfate and heavy metal contents.  

PubMed

Mixed-microbial assemblages enriched from a septic tank, coastal sediment samples, the digester sludge of a brewery wastewater treatment plant and acidic sulfate soil samples were compared on the basis of growth rate, waste and sulfate reduction rate under sulfate reducing conditions at 30 degrees C. The specific growth rate of various cultures was in the range 0.0013-0.0022 hr(-1). Estimates of waste and sulfate reduction rate were obtained by fitting substrate depletion and sulfate reduction data with the Michaelis-Menten equation. The waste reduction rates were in the range 4x10(-8)-1x10(-7) I mg(-1) hr(-1) and generally increased in the presence of copper, likely by copper sulfide precipitation that reduced sulfide and copper toxicity and thus protected the anaerobic microbes. Anaerobic microorganisms from a brewery digester sludge were found to be the most appropriate culture for the treatment of wastewater with high sulfate and heavy metal content due to their growth rate, and waste and sulfate reduction rate. PMID:20112857

Sinbuathong, Nusara; Sirirote, Pramote; Liengcharernsit, Winai; Khaodhiar, Sutha; Watts, Daniel J

2009-01-01

335

Molecular Monitoring of SRB Community Structure and Dynamics in Batch Experiments to Examine the Applicability of in situ Precipitation of Heavy Metals for Groundwater Remediation (15 pp)  

Microsoft Academic Search

Background, Aims and Scope. Sulfate-reducing bacteria (SRB) are known for their capacity to reduce and precipitate heavy metals (HM) as metal sulfides, offering the opportunity to create an in situ reactive zone for the treatment of heavy metalcontaminated groundwater, a process called in situ metal precipitation (ISMP). The applicability of the ISMP technology first has to be investigated at a

Joke Geets; Brigitte Borremans; Jaco Vangronsveld; Ludo Diels; Daniël van der Lelie

2005-01-01

336

Formation of a Precipitate  

NSDL National Science Digital Library

Sometimes when two liquids combine, a solid forms and falls to the bottom of the liquid. This solid is a new substance, called a precipitate, and is evidence that a chemical reaction has occurred. Soap scum, a common example of a precipitate, forms when certain minerals in hard water react with soap molecules. In this activity, students will compare the bubbling of soap-scum-in-water to the bubbling of soap-in-water to show that the soap scum that formed is a different substance than soap.

2010-01-01

337

Interactions of sulfates of divalent metals in nickel-sulfate-sensitive patients.  

PubMed

70 nickel-sensitive subjects who previously gave positive patch test response to 10 microliters of nickel sulfate 0.1 M, were patch tested to 10 microliters of mixed aqueous solutions containing nickel sulfate 0.1 M+magnesium sulfate 0.3 M, nickel sulfate 0.1 M+zinc sulfate, 0.3 and 0.5 M, respectively, nickel sulfate 0.1 M+ manganese sulphate 0.3 and 0.5 M, respectively nickel sulphate 0.1 M+ cadmium sulfate 0.1 and 0.3 M, respectively, nickel sulfate 0.1 M+iron sulfate (III) 0.1 and 0.3 M, respectively, and to 10 microliters of aq. cadmium sulfate 0.1 M, aq. cadmium sulfate 0.3 M, aq. iron sulfate 0.1 M, aq. iron sulfate 0.3 M. The results showed that, whilst sulfates of divalent metals with similar size and redox properties (Mg, Zn and Mn) were able to reduce or to suppress, in a dose-dependent way, the majority (75%) of nickel reactions, those with large radius and different oxidation state(Fe III), generally gave an increase in the reactions. In about 15% of the tested subjects, an increase in all the positive reactions to the mixed solutions was found. The findings seem to demonstrate that in only a majority but not all of nickel sulfate allergic reactions, is Ni(II) able to substitute for divalent ions with similar properties at the ion sites of some proteins. This tendency reproduces the results of experimental systems, in which nickel toxicity and cancerogenity are considered responsible. In contrast, in about 15% of the tested subjects, there was a general enhancement of the reactions. In these cases, either the occurrence of a "hyper-irritable" skin caused by the adopted test system or, more likely, the formation of Ni complexes with different geometries, is hypothesized. PMID:8734915

Santucci, B; Cannistraci, C; Cristaudo, A; Picardo, M

1996-04-01

338

The Effects of Black Carbon and Sulfate Aerosols in ChinaRegions on East Asia Monsoons  

SciTech Connect

In this paper we examine the direct effects of sulfate and black carbon aerosols in China on East Asia monsoons and its precipitation processes by using the CAM3.0 model. It is demonstrated that sulfate and black carbon aerosols in China both have the effects to weaken East Asia monsoons in both summer and winter seasons. However, they certainly differ from each other in affecting vertical structures of temperature and atmospheric circulations. Their differences are expected because of their distinct optical properties, i.e., scattering vs. absorbing. Even for a single type of aerosol, its effects on temperature structures and atmospheric circulations are largely season-dependent. Applications of T-test on our results indicate that forcing from black carbon aerosols over China is relatively weak and limited. It is also evident from our results that the effects of synthetic aerosols (sulfate and black carbon together) on monsoons are not simply a linear summation between these two types of aerosols. Instead, they are determined by their integrated optical properties. Synthetic aerosols to a large degree resemble effects of sulfate aerosols. This implies a likely scattering property for the integration of black carbon and sulfate aerosols in China.

Yang, Bai [ORNL; Liu, Yu [Chinese Academy of Meteorological Sciences, Beijing, China; Sun, Jiaren [South China Institute of Environmental Sciences, Guangzhou, China

2009-01-01

339

Venous intravasation of barium into the inferior mesenteric vein mimicking a coloureteral fistula: a case report and literature review.  

PubMed

Venous intravasation of barium following a barium enema is a rare event. We report a case of barium venous intravasation into the inferior mesenteric vein. Because of the close proximity to the course of the left ureter, this condition was interpreted initially as a coloureteral fistula. After further analysis of the original films, and left retrograde pyelography the true diagnosis was established. A literature review of barium intravasation is presented. PMID:2642308

Baer, H M; Siegelbaum, M H; Seidmon, E J; Kendall, A R

1989-01-01

340

4-Acetyl-pyridinium hydrogen sulfate  

PubMed Central

The crystal structure of the title compound, C7H8NO+·HSO4 ?, consists of O—H?Ohydrogen-bonded extended chains of hydrogen sulfate anions. Each hydrogen sulfate anion is furthermore connected to one 4-acetyl­pyridinium cation via a hydrogen bond of the N—H?O type. PMID:21577849

Fu, Xue-qun

2009-01-01

341

Integrated Spectroscopic Studies of Anhydrous Sulfate Minerals  

NASA Technical Reports Server (NTRS)

Sulfates have been identified in Martian soils and bedrock and are emerging as an important indicator for aqueous activity on Mars. Sulfate minerals can form in a variety of low-temperature (evaporitic; chemical-weathering) and high-temperature (volcanic/fumarolic; hydrothermal) environments and their formational environments can range from alkaline to acidic. Although sulfates generally form in the presence of water, not all sulfates are hydrous or contain water in their structures. Many of these anhydrous sulfates (Dana group 28; Strunz class 67A) are minerals that form as accompanying phases to the main minerals in ore deposits or as replacement deposits in sedimentary rocks. However, some form from thermal decomposition of OH or H2O-bearing sulfates, such as from the reaction [1]: jarosite = yavapaiite + Fe2O3 + H2O. Where known, the stability fields of these minerals all suggest that they would be stable under martian surface conditions [2]. Thus, anhydrous sulfate minerals may contribute to martian surface mineralogy, so they must be well-represented in spectral libraries used for interpretation of the Martian surface. We present here the preliminary results of an integrated study of emittance, reflectance, and Mossbauer spectroscopy of a suite of wel-lcharacterized anhydrous sulfates.

Lane, M. D.; Bishop, J. L.; Dyar, M. D.; Cloutis, E.; Forray, F. L.; Hiroi, T.

2005-01-01

342

Reactivity of calcium sulfate from FBC systems  

Microsoft Academic Search

A relative estimate of the reactivity of calcium sulfate in a number of coal combustion ash samples was obtained, using the rate of solution in water as a parameter. Measurements were also performed on standard samples of calcium sulfate prepared in different ways, for comparison. The temperature of previous treatment appeared as the most important factor determining the reactivity of

Agripanea P. Iribarne; Julio V. Iribarne; Edward J. Anthony

1997-01-01

343

Sulfation phenomena in fluidized bed combustion systems  

Microsoft Academic Search

Fluidized bed combustors (FBCs) are noted for their ability to capture SO2 in situ via direct reaction with Ca-based sorbents. However, despite more than 30 years of intensive study of sulfation processes in atmospheric FBC boilers and numerous laboratory studies, there are still many uncertainties and disagreements on the subject. In particular, the mechanisms of the sulfation reaction are still

E. J. Anthony; D. L. Granatstein

2001-01-01

344

LACK OF EFFECT OF DRINKING WATER BARIUM ON CARDIOVASCULAR RISK FACTORS  

EPA Science Inventory

Higher cardiovascular mortality has been associated in a single epidemiological study with higher levels of barium in drinking water. he 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...

345

Influence of the nature of dopant oxides on the properties of semiconducting barium titanate  

SciTech Connect

This paper presents a thermochemical assessment of the process of doping barium titanate with yttrium, lanthanum, and cerium sesquioxides and their doing capabilities were compared. The thermochemical approach permits the chemical individuality of dopant oxides to be appraised. Yttrium doping of barium titanate is preferable to lanthanum or cerium doping.

Kostikov, Y.P.; Leikina, B.B.

1986-04-01

346

Effect of calcination on characteristics, surface texture and sinterability of chemically prepared barium titanate  

Microsoft Academic Search

Highly pure and finely divided barium titanate powders have been obtained by the pyrolysis of barium titanyl oxalate. The effect of time and temperature of calcination on the degree of crystallinity, fineness, and surface texture of the powders obtained have been demonstrated. The densification properties of the sintered bodies are discussed in relation to the characteristics of the calcined materials.

N. M. Ghoneim; S. Hanafi; Th. Salem

1990-01-01

347

308 Brain Research, 498 (1989) 308-314 Potassium conductance block by barium in amphibian  

E-print Network

.5 to 50.4 MS'2.At corresponding Ba2÷ concentrations, the resistance of cells in situ was somewhat lower). Barium, when applied to the retina, blocks the slow Pill potential3'2°, supporting a M~iller cell origin the effective- ness of Mfiller cells in regulating extracellular K÷ concentration ([K÷]o) in the retina. Barium

Newman, Eric A.

348

Underlayer and substrate effects in RF-magnetron sputtered barium ferrite thin film media  

Microsoft Academic Search

The effect of employing various sputtered underlayers and commercially available substrates in order to optimize the characteristics of barium ferrite (BaM) thin films for magnetic recording media have been studied. Our results show that the choice of underlayer or substrate controls the resultant surface morphology and magnetic properties of the BaM film. In particular, it was found that barium ferrite

A. T. A. Wee; J. P. Wang; A. C. H. Huan; L. P. Tan; R. Gopalakrishnan; K. L. Tan

1997-01-01

349

Relative sensitivity of colonoscopy and barium enema for detection of colorectal cancer in clinical practice  

Microsoft Academic Search

BACKGROUND & AIMS: The relative sensitivities of barium enema and colonoscopy for colorectal cancer are still debated. The aim of this study was to determine the relative sensitivity of barium enema and colonoscopy in general clinical practice. METHODS: Medical records of 2193 consecutive colorectal cancer cases identified in 20 central Indiana hospitals were reviewed. All procedures performed within 3 years

DK Rex; EY Rahmani; JH Haseman; GT Lemmel; S Kaster; JS Buckley

1997-01-01

350

Charge and polarization distributions at the 90 domain wall in barium titanate ferroelectric  

E-print Network

Charge and polarization distributions at the 90° domain wall in barium titanate ferroelectric on quantum mechanics studies to provide a first-principles description of the 90° domain wall in barium in previous analyses, which have suggested domain walls ranging from 100 nm to 1 nm. These results should

Goddard III, William A.

351

Fabrication, characterization and microwave properties of polyurethane nanocomposites reinforced with iron oxide and barium titanate  

E-print Network

with iron oxide and barium titanate nanoparticles Z. Guo a,*, S.-E. Lee a , H. Kim a , S. Park a , H.T. Hahn titanate nanoparticles fabricated by the surface-initiated-polymerization approach were investigated the introduction of the dielectric barium titanate nanoparticle into Fe2O3/PU nanocomposites. The permeability

Guo, John Zhanhu

352

SHORT TERM TOXICITY (1 AND 10 DAY GAVAGE) OF BARIUM CHLORIDE IN MALE AND FEMALE RATS  

EPA Science Inventory

To assess adverse effects that might be caused by an event resulting in high levels of barium in drinking water, rats were gavaged with barium chloride (BaCl2 at dosage levels of 30,100, and 300 rng/kg in a 1-day study and at 100,145,209, and 300 rng/kg for 10 days, and the effec...

353

Bis(chlorido)(dimethyl-sulfoxide-?O)barium(II)  

PubMed Central

The title compound, [BaCl2(C2H6SO)], forms a Ba6Cl9 cluster in which the BaCl2 units are connected via dimethyl­sulfoxide (DMSO) and chloride bridges. The central Cl atom of the Ba6Cl9 cluster is located on a threefold inversion axis and is coordinated octa­hedrally to six barium cations. In the crystal, the clusters are arranged in rows, which are inter­connected by the DMSO mol­ecules, forming a three-dimensional network. PMID:23284316

Gschwind, Fabienne; Jansen, Martin

2012-01-01

354

Atomic Mass and Nuclear Binding Energy for Ba-171 (Barium)  

NASA Astrophysics Data System (ADS)

This document is part of the Supplement containing the complete sets of data of Subvolume B `Nuclei with Z = 55 - 100' of Volume 22 `Nuclear Binding Energies and Atomic Masses' of Landolt-Börnstein - Group I `Elementary Particles, Nuclei and Atoms', and additionally including data for nuclei with Z = 101 - 130. It provides atomic mass, mass excess, nuclear binding energy, nucleon separation energies, Q-values, and nucleon residual interaction parameters for atomic nuclei of the isotope Ba-171 (Barium, atomic number Z = 56, mass number A = 171).

Sukhoruchkin, S. I.; Soroko, Z. N.

355

Dielectric behavior of barium modified strontium bismuth titanate ceramic  

NASA Astrophysics Data System (ADS)

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.

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

2014-04-01

356

Radiation doses to children during modified barium swallow studies  

Microsoft Academic Search

Background  There are minimal data on radiation doses to infants and children undergoing a modified barium swallow (MBS) study.\\u000a \\u000a \\u000a \\u000a Objective  To document screening times, dose area product (DAP) and effective doses to children undergoing MBS and to determine factors\\u000a associated with increased screening times and effective dose.\\u000a \\u000a \\u000a \\u000a Materials and methods  Fluoroscopic data (screening time, DAP, kVp) for 90 consecutive MBS studies using pulse

Kelly A. Weir; Sandra M. McMahon; Gillian Long; Judith A. Bunch; Nirmala Pandeya; Kerry S. Coakley; Anne B. Chang

2007-01-01

357

Development of an RIS probe for barium tagging for EXO  

NASA Astrophysics Data System (ADS)

Resonance Ionization Spectroscopy (RIS) has been shown to be a highly efficient method of selective ionization. We are investigating RIS as part of a high-efficiency single ion transport method to retrieve barium ions produced in double beta decay of xenon-136 and inject them in a ion trap where they are identified via optical spectroscopy. Highly efficient Ba-tagging would substantially reduce the background due to radioactive impurities in very large double-beta decay experiments, which limits the current generation of experiments. RIS is used to re-ionize the Ba atoms after they are desorbed from the substrate on which they had been captured.

Twelker, Karl

2010-11-01

358

Barium alginate cell-delivery systems: correlation between technological parameters.  

PubMed

The most recent trends for the development of several in vitro cell cultures have been oriented towards the cell immobilisation in 3-dimensional scaffolds and cell encapsulation. In fact, an important requirement of cell survival is self-assembly in functional communities, in the presence of an artificial extracellular matrix. In our research, a previously described technique for spermatozoa encapsulation was applied to obtain capsules loaded with an opaque agent as a model, and to perform a formulative study. A process variable, barium ion concentration, was correlated to some capsule properties, such as weight, gel thickness, total and core diameter. Ion concentration can be modified to obtain capsules with predictable characteristics. PMID:12176286

Torre, M L; Faustini, M; Norberti, R; Maggi, L; Maffeo, G; Conte, U; Vigo, D

2002-08-21

359

Radium and barium in the Amazon River system  

SciTech Connect

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.

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

1984-03-20

360

Evidence against Barium in the Mushroom Trogia venenata as a Cause of Sudden Unexpected Deaths in Yunnan, China  

PubMed Central

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. PMID:23042168

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

2012-01-01

361

Scintillation properties of lead sulfate  

SciTech Connect

We report on the scintillation properties of lead sulfate (PbSO{sub 4}), a scintillator that show promise as a high energy photon detector. It physical properties are well suited for gamma detection, as its has a density of 6.4 gm/cm{sup 3}, a 1/e attenuation length for 511 keV photons of 1.2 cm, is not affected by air or moisture, and is cut and polished easily. In 99.998% pure PbSO{sub 4} crystals at room temperature excited by 511 keV annihilation photons, the fluorescence decay lifetime contains significant fast components having 1.8 ns (5%) and 19 ns (36%) decay times, but with longer components having 95 ns (36%) and 425 ns (23%) decays times. The peak emission wavelength is 335 nm, which is transmitted by borosilicate glass windowed photomultiplier tubes. The total scintillation light output increases with decreasing temperature fro 3,200 photons/MeV at +45{degrees}C to 4, 900 photons/MeV at room temperature (+25{degrees}C) and 68,500 photons/MeV at {minus}145{degrees}C. In an imperfect, 3 mm cube of a naturally occurring mineral form of PbSO{sub 4} (anglesite) at room temperature, a 511 keV photopeak is seen with a total light output of 60% that BGO. There are significant sample to sample variations of the light output among anglesite samples, so the light output of lead sulfate may improve when large synthetic crystals become available. 10 refs.

Moses, W.W.; Derenzo, S.E. [Lawrence Berkeley Lab., CA (United States); Shlichta, P.J. [Crystal Research, San Pedro, CA (United States)

1991-11-01

362

Crystallization of Chicken Egg White Lysozyme from Assorted Sulfate Salts  

NASA Technical Reports Server (NTRS)

Chicken egg white lysozyme has been found to crystallize from ammonium, sodium, potassium, rubidium, magnesium, and manganese sulfates at acidic and basic pH, with protein concentrations from 60 to 190 mg/ml. Crystals have also been grown at 4 C in the absence of any other added salts using isoionic lysozyme which was titrated to pH 4.6 with dilute sulfuric acid. Four different crystal forms have been obtained, depending upon the temperature, protein concentration, and precipitating salt employed. Crystals grown at 15 C were generally tetragonal, with space group P4(sub 3)2(sub 1)2. Crystallization at 20 C typically resulted in the formation of orthorhombic crystals, space group P2(sub 1)2(sub 1)2(sub 1). The tetragonal reversible reaction orthorhombic transition appeared to be a function of both the temperature and protein concentration, occurring between 15 and 20 C and between 100 and 125 mg/ml protein concentration. Crystallization from 1.2 M magnesium sulfate at pH 7.8 gave a trigonal crystal, space group P3(sub 1)2(sub 1), a = b = 87.4, c = 73.7, gamma = 120 deg, which diffracted to 2.8 A. Crystallization from ammonium sulfate at pH 4.6, generally at lower temperatures, was also found to result in a monoclinic form. space group C2, a = 65.6, b = 95.0, c = 41.2, beta = 119.2 deg. A crystal of approximately 0.2 x 0.2 x 0.5 mm grown from bulk solution diffracted to approximately 3.5 A.

Forsythe, Elizabeth L.; Snell, Edward H.; Malone, Christine C.; Pusey, Marc L.

1999-01-01

363

Setting process of lime-based conservation mortars with barium hydroxide  

SciTech Connect

This paper presents the effect of barium hydroxide on the setting mechanism of lime-based conservation mortars, when used as an additive material. The study focuses on the monitoring of the setting process and the identification of the mineral phases formed, which are essential for furthering the study of the durability of barium mixtures against chemical degradation. X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and thermal analysis (DTA-TG) were used to monitor the setting processes of these mixtures and identify new phases formed. The results suggest that barium hydroxide is evenly distributed within the lime and produces a homogeneous binding material, consisting of calcite (CaCO{sub 3}), witherite (BaCO{sub 3}) and barium-calcium carbonate [BaCa(CO{sub 3}){sub 2}]. Finally, it was found that barium carbonate can be directly bonded to calcitic aggregates and therefore increases its chemical compatibility with the binding material.

Karatasios, Ioannis [Institute of Materials Science, NCSR Demokritos, Aghia Paraskevi, 153 10 Athens (Greece)]. E-mail: ikarat@ims.demokritos.gr; Kilikoglou, Vassilis [Institute of Materials Science, NCSR Demokritos, Aghia Paraskevi, 153 10 Athens (Greece); Colston, Belinda [Department of Forensic and Biomedical Sciences, University of Lincoln, Lincoln, LN6 7TS (United Kingdom); Theoulakis, Panagiotis [Department of Conservation of Antiquities and Works of Art, TEI of Athens, Athens, 122 10 (Greece); Watt, David [Hutton and Rostron Environmental Investigations Limited/Centre for Sustainable Heritage, University College London (United Kingdom)

2007-06-15

364

Photometric Calibration of the Barium Cloud Image in a Space Active Experiment: Determining the Release Efficiency  

NASA Astrophysics Data System (ADS)

The barium release experiment is an effective method to explore the near-earth environment and to study all kinds of space physics processes. The first space barium release experiment in China was successfully carried out by a sounding rocket on April 5, 2013. This work is devoted to calculating the release efficiency of the barium release by analyzing the optical image observed during the experiment. First, we present a method to calibrate the images grey value of barium cloud with the reference stars to obtain the radiant fluxes at different moments. Then the release efficiency is obtained by a curve fitting with the theoretical evolution model of barium cloud. The calculated result is basically consistent with the test value on ground.

Xie, Liang-Hai; Li, Lei; Wang, Jing-Dong; Tao, Ran; Cheng, Bing-Jun; Zhang, Yi-Teng

2014-01-01

365

21 CFR 182.1127 - Aluminum ammonium sulfate.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Aluminum ammonium sulfate. 182.1127 Section...Purpose GRAS Food Substances § 182.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate. (b) Conditions...

2012-04-01

366

21 CFR 582.1127 - Aluminum ammonium sulfate.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Aluminum ammonium sulfate. 582.1127 Section...General Purpose Food Additives § 582.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate. (b) Conditions...

2012-04-01

367

21 CFR 182.1131 - Aluminum sodium sulfate.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Aluminum sodium sulfate. 182.1131 Section 182...Purpose GRAS Food Substances § 182.1131 Aluminum sodium sulfate. (a) Product. Aluminum sodium sulfate. (b) Conditions of...

2012-04-01

368

21 CFR 582.1131 - Aluminum sodium sulfate.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Aluminum sodium sulfate. 582.1131 Section 582...General Purpose Food Additives § 582.1131 Aluminum sodium sulfate. (a) Product. Aluminum sodium sulfate. (b) Conditions of...

2012-04-01

369

21 CFR 522.62 - Aminopentamide hydrogen sulfate injection.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 false Aminopentamide hydrogen sulfate injection. 522.62 Section...ANIMAL DRUGS § 522.62 Aminopentamide hydrogen sulfate injection. (a) Chemical...Dimethylamino)-2,2-diphenylvaleramide hydrogen sulfate. (b)...

2012-04-01

370

21 CFR 520.1044a - Gentamicin sulfate oral solution.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Gentamicin sulfate oral solution. 520.1044a Section 520.1044a...520.1044a Gentamicin sulfate oral solution. (a) Specifications. Each milliliter of aqueous solution contains gentamicin sulfate...

2011-04-01

371

21 CFR 529.1044b - Gentamicin sulfate solution.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 false Gentamicin sulfate solution. 529.1044b Section 529.1044b...DRUGS § 529.1044b Gentamicin sulfate solution. (a) Specifications. Each milliliter of solution contains gentamicin sulfate...

2011-04-01

372

21 CFR 520.1044a - Gentamicin sulfate oral solution.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Gentamicin sulfate oral solution. 520.1044a Section 520.1044a...520.1044a Gentamicin sulfate oral solution. (a) Specifications. Each milliliter of aqueous solution contains gentamicin sulfate...

2010-04-01

373

Physiology of multiple sulfur isotope fractionation during microbial sulfate reduction  

E-print Network

Microbial sulfate reduction (MSR) utilizes sulfate as an electron acceptor and produces sulfide that is depleted in heavy isotopes of sulfur relative to starting sulfate. The fractionation of S-isotopes is commonly used ...

Sim, Min Sub

2012-01-01

374

The Global Precipitation Mission  

NASA Technical Reports Server (NTRS)

The Global Precipitation Mission (GPM), expected to begin around 2006, is a follow-up to the Tropical Rainfall Measuring Mission (TRMM). Unlike TRMM, which primarily samples the tropics, GPM will sample both the tropics and mid-latitudes. The primary, or core, satellite will be a single, enhanced TRMM satellite that can quantify the 3-D spatial distributions of precipitation and its associated latent heat release. The core satellite will be complemented by a constellation of very small and inexpensive drones with passive microwave instruments that will sample the rainfall with sufficient frequency to be not only of climate interest, but also have local, short-term impacts by providing global rainfall coverage at approx. 3 h intervals. The data is expected to have substantial impact upon quantitative precipitation estimation/forecasting and data assimilation into global and mesoscale numerical models. Based upon previous studies of rainfall data assimilation, GPM is expected to lead to significant improvements in forecasts of extratropical and tropical cyclones. For example, GPM rainfall data can provide improved initialization of frontal systems over the Pacific and Atlantic Oceans. The purpose of this talk is to provide information about GPM to the USWRP (U.S. Weather Research Program) community and to discuss impacts on quantitative precipitation estimation/forecasting and data assimilation.

Braun, Scott; Kummerow, Christian

2000-01-01

375

Precipitation probes intercomparison  

Microsoft Academic Search

Two versions of precipitation probes were mounted on a C-130 E aircraft. Correlation flights, simultaneous aircraft, and radar measurements were made over Kwajalein in September and October, 1974. The two probes differed primarily in their resolution and the maximum measurable crystal size. The narrow-arm version of the probes had a 150 micrometer size resolution and was able to measure crystals

E. S. Lobl

1978-01-01

376

EFFECTS OF ACID PRECIPITATION  

EPA Science Inventory

Recent reviews of available data indicate that precipitation in a large region of North America is highly acidic when its pH is compared with the expected pH value of 5.65 for pure rain water in equilibrium with CO2. A growing body of evidence suggests that acid rain is responsib...

377

Wet electrostatic precipitators  

Microsoft Academic Search

The precipitator includes main sections each having a plurality of spaced parallel collection plates with discharge electrodes being interposed between the collection plates. The plates extend in the direction of flow of a gaseous medium. Sprays of water are continuously directed against the collection plates. The gas enters through a diverging inlet section in which there are arranged several sets

Bakke

1978-01-01

378

Global precipitation measurement (GPM)  

NASA Astrophysics Data System (ADS)

The National Aeronautics and Space Administration (NASA) is studying options for future space-based missions for the EOS Follow-on Era (post 2003), building upon the measurements made by Pre-EOS and EOS First Series Missions. One mission under consideration is the Global Precipitation Measurement (GPM), a cooperative venture of NASA, Japan, and other international partners. GPM will capitalize on the experience of the highly successful Tropical Rainfall Measurement Mission (TRMM). Its goal is to extend the measurement of rainfall to high latitudes with high temporal frequency, providing a global data set every three hours. A reference concept has been developed consisting of an improved TRMM-like primary satellite with precipitation radar and microwave radiometer to make detailed and accurate estimates of the precipitation structure and a constellation of small satellites flying compact microwave radiometers to provide the required temporal sampling of highly variable precipitation systems. Considering that DMSP spacecraft equipped with SSMIS microwave radiometers, successor NPOESS spacecraft equipped with CMIS microwave radiometers, and other relevant international systems are expected to be in operation during the timeframe of the reference concept, the total number of small satellites required to complete the constellation will be reduced. A nominal plan is to begin implementation in FY'03 with launches in 2007. NASA is presently engaged in advanced mission studies and advanced instrument technology development related to the mission.

Neeck, Steven P.; Flaming, Gilbert M.; Adams, W. James; Smith, Eric A.

2001-12-01

379

Total Precipitable Water  

SciTech Connect

The simulation was performed on 64K cores of Intrepid, running at 0.25 simulated-years-per-day and taking 25 million core-hours. This is the first simulation using both the CAM5 physics and the highly scalable spectral element dynamical core. The animation of Total Precipitable Water clearly shows hurricanes developing in the Atlantic and Pacific.

None

2012-01-01

380

High Rates of Sulfate Reduction in a Low-Sulfate Hot Spring Microbial Mat Are Driven by a Low Level of Diversity of Sulfate-Respiring Microorganisms  

Microsoft Academic Search

The importance of sulfate respiration in the microbial mat found in the low-sulfate thermal outflow of Mushroom Spring in Yellowstone National Park was evaluated using a combination of molecular, microelec- trode, and radiotracer studies. Despite very low sulfate concentrations, this mat community was shown to sustain a highly active sulfur cycle. The highest rates of sulfate respiration were measured close

Jesse G. Dillon; Susan Fishbain; Scott R. Miller; Brad M. Bebout; Kirsten S. Habicht; Samuel M. Webb; David A. Stahl

2007-01-01

381

Bacterial transport of sulfate, molybdate, and related oxyanions  

Microsoft Academic Search

Sulfur is an essential element for microorganisms and it can be obtained from varied compounds, sulfate being the preferred\\u000a source. The first step for sulfate assimilation, sulfate uptake, has been studied in several bacterial species. This article\\u000a reviews the properties of different bacterial (and archaeal) transporters for sulfate, molybdate, and related oxyanions. Sulfate\\u000a uptake is carried out by sulfate permeases

Esther Aguilar-Barajas; César Díaz-Pérez; Martha I. Ramírez-Díaz; Héctor Riveros-Rosas; Carlos Cervantes

2011-01-01

382

Precipitation Indices Low Countries  

NASA Astrophysics Data System (ADS)

Since 1995, KNMI published a series of books(1), presenting an annual reconstruction of weather and climate in the Low Countries, covering the period AD 763-present, or roughly, the last millennium. The reconstructions are based on the interpretation of documentary sources predominantly and comparison with other proxies and instrumental observations. The series also comprises a number of classifications. Amongst them annual classifications for winter and summer temperature and for winter and summer dryness-wetness. The classification of temperature have been reworked into peer reviewed (2) series (AD 1000-present) of seasonal temperatures and temperature indices, the so called LCT (Low Countries Temperature) series, now incorporated in the Millennium databases. Recently we started a study to convert the dryness-wetness classifications into a series of precipitation; the so called LCP (Low Countries Precipitation) series. A brief outline is given here of the applied methodology and preliminary results. The WMO definition for meteorological drought has been followed being that a period is called wet respectively dry when the amount of precipitation is considerable more respectively less than usual (normal). To gain a more quantitative insight for four locations, geographically spread over the Low Countries area (De Bilt, Vlissingen, Maastricht and Uccle), we analysed the statistics of daily precipitation series, covering the period 1900-present. This brought us to the following definition, valid for the Low Countries: A period is considered as (very) dry respectively (very) wet if over a continuous period of at least 60 days (~two months) cq 90 days (~three months) on at least two out of the four locations 50% less resp. 50% more than the normal amount for the location (based on the 1961-1990 normal period) has been measured. This results into the following classification into five drought classes hat could be applied to non instrumental observations: Very wet period (+2): Wide scale river flooding, marshy acres and meadows.-Farmers cope with poor harvests of hay, grains, fruit etc. resulting in famines.-Late grape harvests, poor yield quantity and quality of wine. Wet period (+1): High water levels cq discharges of major rivers, tributaries and brooks, local river floodings, marshy acres and meadows in the low lying areas.-Wearisome and hampered agriculture. Normal (0) Dry period (-1): Low water levels cq discharges of major rivers, tributaries and brooks. Some brooks may dry up.-Summer half year: local short of yield of grass, hay and other forage.-Summer half year: moor-, peat- and forest fires. Very dry period (-2): Very low water levels cq discharges of major rivers and tributaries. Brooks and wells dry up. Serious shortage of drinking water; especially in summer.-Major agricultural damage, shortage of water, mortality stock of cattle. Shortage of grain. Flour can not be produced due to water mills running out of water, shortage of bread, bread riots, famines.-Large scale forest and peat areas, resulting in serious air pollution. Town fires. By verifying the historical evidence on these criterions, a series of 5 step indices ranging from very dry to very wet for summer and winter half year of the Low Countries was obtained. Subsequently these indices series were compared with the instrumentally observed seasonal precipitation sums for De Bilt (1735-2008), which is considered to be representative for the Central Netherlands. For winter (Oct-March) and summer half year (Apr.-Sept.) the accumulated precipitation amounts are calculated; these amounts are approximately normally distributed. Based on this distribution, the cumulative frequency distribution is calculated. By tabulating the number of summers in the pre-instrumental period 1201-1750 for each of the drought classes, a distribution is calculated which is then related to the modern accumulated precipitation distribution. Assuming that the accumulated precipitation amount has not been below (above) the mean precipitation minus (plus) three standard deviations for

van Engelen, A. F. V.; Ynsen, F.; Buisman, J.; van der Schrier, G.

2009-09-01

383

Plasma waves associated with the first AMPTE magnetotail barium release  

NASA Technical Reports Server (NTRS)

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.

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

1986-01-01

384

Results of magnetospheric barium ion cloud experiment of 1971  

NASA Technical Reports Server (NTRS)

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.

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

1975-01-01

385

Barium titanate core - gold shell nanoparticles for hyperthermia treatments  

PubMed Central

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 ?g/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 ?g/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

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

2013-01-01

386

Revisiting the dissimilatory sulfate reduction pathway.  

PubMed

Sulfur isotopes in the geological record integrate a combination of biological and diagenetic influences, but a key control on the ratio of sulfur isotopes in sedimentary materials is the magnitude of isotope fractionation imparted during dissimilatory sulfate reduction. This fractionation is controlled by the flux of sulfur through the network of chemical reactions involved in sulfate reduction and by the isotope effect associated with each of these chemical reactions. Despite its importance, the network of reactions constituting sulfate reduction is not fully understood, with two principle networks underpinning most isotope models. In this study, we build on biochemical data and recently solved crystal structures of enzymes to propose a revised network topology for the flow of sulfur through the sulfate reduction metabolism. This network is highly branched and under certain conditions produces results consistent with the observations that motivated previous sulfate reduction models. Our revised network suggests that there are two main paths to sulfide production: one that involves the production of thionate intermediates, and one that does not. We suggest that a key factor in determining sulfur isotope fractionation associated with sulfate reduction is the ratio of the rate at which electrons are supplied to subunits of Dsr vs. the rate of sulfite delivery to the active site of Dsr. This reaction network may help geochemists to better understand the relationship between the physiology of sulfate reduction and the isotopic record it produces. PMID:21884365

Bradley, A S; Leavitt, W D; Johnston, D T

2011-09-01

387

Direct Precipitation of Spinel-Type Zn(Fe, Ga) 2O 4 Solid Solutions from Aqueous Solutions at 90°C: Influence of Iron Valence of Starting Salt on Their Crystallite Growth  

Microsoft Academic Search

Spinel-type solid solutions in the whole range of compositions between ZnGa2O4 and ZnFe2O4 were directly precipitated as nanoparticles by dropping the starting mixed solutions of zinc sulfate, gallium sulfate, and either divalent iron chloride or trivalent iron nitrate into aqueous ammonia at 90°C. Direct precipitation of nanosized spinel-type Zn(Ga,Fe)O4 solid solutions was also achieved by aging the mixed solutions in

Masanori Hirano; Shiro Okumura; Yasunori Hasegawa; Michio Inagaki

2002-01-01

388

Annual variations in chemical composition of atmospheric precipitation, eastern North Carolina and southeastern Virginia  

USGS Publications Warehouse

A 2-year study of precipitation composition over eastern North Carolina and southeastern Virginia has been completed. Chemical analyses were made of the major ions in monthly rainfall samples from each of 12 sampling locations. Areal and seasonal distributions were determined for chloride, calcium, magnesium, sodium, potassium, sulfate, and nitrate. Annual changes in loads and in geographical distribution of sulfate and of nitrate are small. Yearly rainfall sulfate loads amount to approximately 7 tons per square mile, whereas deposition of nitrate is about 2 tons per square mile per year in the interior of the network and less near the coast. Areal patterns of chloride content are consistent with the assumption that the ocean is the only major source of rainfall chloride in the area. Chloride loads were 2.1 and 1.8 tons per square mile per year; the difference can be attributed to meteorological conditions. Cation concentrations in network precipitation appear to depend on localized sources, probably soil dust. Annual loads of the major cations are approximately 2 tons per square mile of calcium, 1.8 tons per square mile of sodium, 0.5 ton per square mile of magnesium, and 0.3 ton per square mile of potassium; considerable year-to-year differences were noted in these values. Bicarbonate and hydrogen ion in network rainfall are closely related to the relative concentrations of sulfate and calcium. Apparently, reaction of an acidic sulfur-containing aerosol with an alkaline calcium source is one of the principal controls on precipitation alkalinity and pH. Ions in precipitation contribute substantially to the quality of surface water in the network area. Comparisons between precipitation input and stream export of ions for four North Carolina rivers show that rainfall sulfate is equal to sulfate discharged, whereas nitrate in rain slightly exceeds stream nitrate. Contributions of cations to the streams by way of precipitation range from about 20 percent for potassium to almost 50 percent for calcium. Chloride deposited by precipitation amounts to about one-fourth of the stream load. Additions of manufactured salt may account for much of the remainder of the surface-water load.

Fisher, Donald W.

1967-01-01

389

Sulfate attack in lime-treated subbases  

SciTech Connect

Sulfate-induced heave or buckling in pavements is the phenomenon that occurs when the calcium in various lime-based stabilizers combines with the alumina and sulfate present in clay to form calcium sulfoaluminate, or ettringite. Ettringite, a crystal, can grow between clay particles, pushing them apart and causing swelling in the soil. When this happens in pavement subbases, the resulting heaving may cause the pavement to rupture and fail, sometimes in a dramatic way. In this paper the authors examine the mechanism of sulfate attack, review some of the work done on this problem, and present some examples of pavement failures.

Day, D.C.; Salami, M.R. [North Carolina A and T State Univ., Greensboro, NC (United States). Dept. of Civil Engineering; Rollings, R.S. [Army Engineering Waterways Experiment Station, Vicksburg, MS (United States). Pavement Div.

1995-06-01

390

Chlorate: a reversible inhibitor of proteoglycan sulfation  

SciTech Connect

Bovine aorta endothelial cells were cultured in medium containing (/sup 3/H)glucosamine, (/sup 35/S)sulfate, and various concentrations of chlorate. Cell growth was not affected by 10 mM chlorate, while 30 mM chlorate had a slight inhibitory effect. Chlorate concentrations greater than 10 mM resulted in significant undersulfation of chondroitin. With 30 mM chlorate, sulfation of chondroitin was reduced to 10% and heparan to 35% of controls, but (/sup 3/H)glucosamine incorporation on a per cell basis did not appear to be inhibited. Removal of chlorate from the culture medium of cells resulted in the rapid resumption of sulfation.

Humphries, D.E.; Silbert, J.E.

1988-07-15

391

Topics in Precipitation Type Forecasting  

NSDL National Science Digital Library

This module presents an overview of various aspects of precipitation type forecasting. It includes sections on microphysics and the ice crystal process, application of partial thickness analysis, application precipitation type analysis.

Spangler, Tim

2005-09-27

392

Improved methodology for bioremoval of black crusts on historical stone artworks by use of sulfate-reducing bacteria.  

PubMed

An improved methodology to remove black crusts from stone by using Desulfovibrio vulgaris subsp. vulgaris ATCC 29579, a sulfate-reducing bacterium, is presented. The strain removed 98% of the sulfates of the crust in a 45-h treatment. Precipitation of black iron sulfide was avoided using filtration of a medium devoid of iron. Among three cell carriers, Carbogel proved to be superior to both sepiolite and Hydrobiogel-97, as it allowed an easy application of the bacteria, kept the system in a state where microbial activity was maintained, and allowed easy removal of the cells after the treatment. PMID:16672524

Cappitelli, Francesca; Zanardini, Elisabetta; Ranalli, Giancarlo; Mello, Emilio; Daffonchio, Daniele; Sorlini, Claudia

2006-05-01

393

A precipitation sampler intercomparison  

Microsoft Academic Search

A three month experimental study to evaluate the relative performance of three different designs of ‘event’ precipitation chemistry samplers was carried out at Woodbridge, Ontario beginning in August 1979. The samplers evaluated were an automatic Aerochem Metrics, ‘wet-only’ type (A), a funnel-and-bottle type (F), and a large-mouth plastic bucket with a specially-fabricated polyethylene bag insert (S). Each sampler was run

Walter H. Chan; Maris A. Lusis; R. D. Samuel Stevens; Robert J. Vet

1984-01-01

394

Precipitation hardening austenitic superalloys  

DOEpatents

Precipitation hardening, austenitic type superalloys are described. These alloys contain 0.5 to 1.5 weight percent silicon in combination with about 0.05 to 0.5 weight percent of a post irradiation ductility enhancing agent selected from the group of hafnium, yttrium, lanthanum and scandium, alone or in combination with each other. In addition, when hafnium or yttrium are selected, reductions in irradiation induced swelling have been noted.

Korenko, Michael K. (Wexford, PA)

1985-01-01

395

Uncertainties in Arctic Precipitation  

NASA Astrophysics Data System (ADS)

Arctic precipitation is riddled with measurement biases; to address the problem is imperative. Our study focuses on comparison of various datasets and analyzing their biases for the region of Siberia and caution that is needed when using them. Five sources of data were used ranging from NOAA's product (RAW, Bogdanova's correction), Yang's correction technique and two reanalysis products (ERA-Interim and NCEP). The reanalysis dataset performed better for some months in comparison to Yang's product, which tends to overestimate precipitation, and the raw dataset, which tends to underestimate. The sources of bias vary from topography, to wind, to missing data .The final three products chosen show higher biases during the winter and spring season. Emphasis on equations which incorporate blizzards, blowing snow and higher wind speed is necessary for regions which are influenced by any or all of these factors; Bogdanova's correction technique is the most robust of all the datasets analyzed and gives the most reasonable results. One of our future goals is to analyze the impact of precipitation uncertainties on water budget analysis for the Siberian Rivers.

Majhi, I.; Alexeev, V. A.; Cherry, J. E.; Cohen, J. L.; Groisman, P. Y.

2012-12-01

396

Inhibition of bacterial oxidation of ferrous iron by lead nitrate in sulfate-rich systems  

USGS Publications Warehouse

Inhibition of bacterial oxidation of ferrous iron (Fe(II)) by Pb(NO3)2 was investigated with a mixed culture of Acidithiobacillus ferrooxidans. The culture was incubated at 30 °C in ferrous-sulfate medium amended with 0–24.2 mM Pb(II) added as Pb(NO3)2. Anglesite (PbSO4) precipitated immediately upon Pb addition and was the only solid phase detected in the abiotic controls. Both anglesite and jarosite (KFe3(SO4)2(OH)6) were detected in inoculated cultures. Precipitation of anglesite maintained dissolved Pb concentrations at 16.9–17.6 ?M regardless of the concentrations of Pb(NO3)2 added. Fe(II) oxidation was suppressed by 24.2 mM Pb(NO3)2 addition even when anglesite was removed before inoculation. Experiments with 0–48 mM KNO3 demonstrated that bacterial Fe(II) oxidation decreased as nitrate concentration increased. Therefore, inhibition of Fe(II) oxidation at 24.2 mM Pb(NO3)2 addition resulted from nitrate toxicity instead of Pb addition. Geochemical modeling that considered the initial precipitation of anglesite to equilibrium followed by progressive oxidation of Fe(II) and the precipitation of jarosite and an amorphous iron hydroxide phase, without allowing plumbojarosite to precipitate were consistent with the experimental time-series data on Fe(II) oxidation under biotic conditions. Anglesite precipitation in mine tailings and other sulfate-rich systems maintains dissolved Pb concentrations below the toxicity threshold of A. ferrooxidans.

Wang, Hongmei; Gong, Linfeng; Cravotta, Charles A.; Yang, Xiaofen; Tuovinen, Olli H.; Dong, Hailiang; Fu, Xiang

2013-01-01

397

Precipitation of heavy metals from coal ash leachate using biogenic hydrogen sulfide generated from FGD gypsum.  

PubMed

Investigations were undertaken to utilize flue gas desulfurization (FGD) gypsum for the treatment of leachate from the coal ash (CA) dump sites. Bench-scale investigations consisted of three main steps namely hydrogen sulfide (H(2)S) production by sulfate reducing bacteria (SRB) using sulfate from solubilized FGD gypsum as the electron acceptor, followed by leaching of heavy metals (HMs) from coal bottom ash (CBA) and subsequent precipitation of HMs using biologically produced sulfide. Leaching tests of CBA carried out at acidic pH revealed the existence of several HMs such as Cd, Cr, Hg, Pb, Mn, Cu, Ni and Zn. Molasses was used as the electron donor for the biological sulfate reduction (BSR) process which produced sulfide rich effluent with concentration up to 150 mg/L. Sulfide rich effluent from the sulfate reduction process was used to precipitate HMs as metal sulfides from CBA leachate. HM removal in the range from 40 to 100% was obtained through sulfide precipitation. PMID:23168629

Jayaranjan, Madawala Liyanage Duminda; Annachhatre, Ajit P

2013-01-01

398

Effect of precipitation on low frequency electrical properties of zerovalent iron columns.  

PubMed

We conducted column studies to investigate the application of a noninvasive electrical method to monitor precipitation in Fe0 columns using (a) Na2SO4 (0.01 M, dissolved oxygen (DO) = 8.8 ppm), and (b) Na2CO3 (0.01 M, DO = 2.3 ppm) solutions. An increase in complex conductivity terms (maximum 40% in sulfate column and 23% in carbonate column) occurred over 25 days. Scanning electron microscopy (SEM) identified mineral surface alteration, with greater changes in the high DO sulfate column relative to the low DO carbonate column. X-ray diffractometry (XRD) identified reduced amounts of hematite/maghemite in both columns, precipitation of goethite/akaganeite in the sulfate column, and precipitation of siderite in the carbonate column. Nitrogen adsorption measurements showed increases in specific surface area of iron minerals (27.5% for sulfate column and 8.2% for carbonate column). As variations in electrolytic conductivity and porosity were minimal, electrical changes are attributed to (1) higher complex interfacial conductivity due to increased surface area and mineralogical alteration and (2) increased electronic conduction due to enhanced electron transfer across the iron-fluid interface. Our results show that electrical measurements are a proxy indicator of Fe0 surface alteration. PMID:16382942

Wu, Yuxin; Slater, Lee D; Korte, Nic

2005-12-01

399

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

PubMed

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. PMID:20354061

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

2011-01-01

400

The Evolving Mixture of Barium Isotopes in Milky Way Halo Stars  

NASA Astrophysics Data System (ADS)

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.

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

2014-01-01

401

Estimation of continental precipitation recycling  

Microsoft Academic Search

The total amount of water that precipitates on large continental regions is supplied by two mechanisms: (1) advection from the surrounding areas external to the region and (2) evaporation and transpiration from the land surface within the region. The latter supply mechanism is tantamount to the recycling of precipitation over the Continental area. The degree to which regional precipitation is

Kaye L. Brubaker; Dara Entekhabi; P. S. Eagleson

1993-01-01

402

4, 23232360, 2007 Extreme precipitation  

E-print Network

HESSD 4, 2323­2360, 2007 Extreme precipitation and extreme streamflow W. Wang et al. Title Page are under open-access review for the journal Hydrology and Earth System Sciences Extreme precipitation Correspondence to: W. Wang (w.wang@126.com) 2323 #12;HESSD 4, 2323­2360, 2007 Extreme precipitation and extreme

Boyer, Edmond

403

REGIONAL ANALYSIS OF EXTREME PRECIPITATION  

E-print Network

REGIONAL ANALYSIS OF EXTREME PRECIPITATION EVENTS IN THE CZECH REPUBLIC Jan Kyselý1 , Jan Picek2: - daily precipitation amounts measured at 78 stations covering the Czech Republic (area of 78 864 square the period of 1961-2000; there are no missing values in this dataset. Extreme precipitation events: - maximum

Jureckova, Jana

404

Duskside relativistic electron precipitation  

NASA Astrophysics Data System (ADS)

On August 20, 1996, a balloon-borne X-ray pinhole camera and a high resolution germanium X-ray spectrometer observed an intense X-ray event near Kiruna, Sweden, at 1835 MLT, on an L-shell of 5.8. This X-ray event consisted of seven bursts spaced 100-200 seconds apart, with smaller 10-20 second variations observed within individual bursts. The energy spectra of these bursts show the presence of X-rays with energies greater than 1 MeV, which are best accounted for by atmospheric bremsstrahlung from mono-energetic 1.7 MeV precipitating electrons. The X-ray imager observed no significant motion or small-scale spatial structure in the event, implying that the bursts were temporal in nature. Ultra- violet images from the Polar satellite and energetic particle data from the Los Alamos geosynchronous satellites show a small magnetospheric substorm onset about 24 minutes before the start of the relativistic precipitation event. Since the balloon was south of the auroral oval and there was no associated increase in relativistic electron flux at geosynchronous altitude, the event must be the result of some mechanism selectively precipitating ambient relativistic electrons from the radiation belts. The balloon X-ray observations are analyzed in a magnetospheric context, in order to determine which of several mechanisms for selective precipitation of relativistic electrons can account for the event. Resonance with electromagnetic ion cyclotron mode waves on the equator is the most likely candidate. The drift of substorm-injected warm protons is calculated using input from the geosynchronous satellites. Wave growth in the model is driven by temperature anisotropies in the warm proton population. A numerical solution of the wave dispersion relation shows that electromagnetic ion cyclotron waves can be excited in high-density duskside regions such as the plasmasphere or detached plasma regions. These waves can selectively precipitate relativistic electrons of energy 1.7 MeV in regions of density greater than 10 cm-3 , given the appropriate warm proton temperature, density, and anisotropy. The model is used to investigate the effects of variations in these free parameters, and shows that only a narrow range of values can produce waves that interact with 1.7 MeV electrons.

Lorentzen, Kirsten Ruth

1999-10-01

405

Enrichment method of sulfated glycopeptides by a sulfate emerging and ion exchange chromatography.  

PubMed

Sulfated glycoproteins are of growing importance for biomarker discovery, as well as for investigating molecular recognition processes. Mass spectrometry (MS) has become a powerful technique for the characterization of glycans and glycoproteins. However, characterization and detection of sulfated glycopeptides by MS is difficult because of the low abundance and low ionization efficiency of these molecules. To overcome this problem, we developed a novel enrichment procedure for sulfated glycopeptides. The procedure consists of anion exchange chromatography and a sulfate emerging (SE) method which controls the net charge of peptides by utilizing limited proteolyzes and modification with acetohydrazide. Using this procedure, we are able to enrich and characterize the sulfated glycopeptides of bovine luteinizing hormone (bLH). Furthermore, we demonstrate the enrichment and detection of sulfated glycopeptides from a complex mixture comprising human serum spiked with bLH at a concentration of 0.1%. PMID:19572564

Toyoda, Masaaki; Narimatsu, Hisashi; Kameyama, Akihiko

2009-08-01

406

Clays and Sulfates in a Potential Lacustrine Evaporite Sequence at Columbus Crater, Mars  

NASA Astrophysics Data System (ADS)

From orbit, phyllosilicates and hydrated sulfates on Mars have typically been observed in distinct geographic locales and are thought to record different types of ancient aqueous environments [1]. However, these two mineral classes have recently been found in close association in each of two large impact craters in the Terra Sirenum region of the Southern highlands [2, 3]. In one of these, the D~100 km crater Columbus, CRISM observations show that a polyhydrated non-Fe sulfate is the spatially dominant phase, whereas other distinct layers have spectra consistent with the iron sulfates jarosite and szomolnokite, respectively. Another distinct spectral unit may contain hydrated chloride, or a different non-Fe sulfate. A kaolin group clay is the most commonly detected phyllosilicate, occurring in all CRISM scenes that show the polyhydrated sulfate, but Fe/Mg-phyllosilicates are also seen in small exposures. The polyhydrated sulfate occurs in a light-toned, finely layered, indurated deposit that extends around ~270 degrees of the inner crater wall. The kaolinite unit is commonly stratigraphically beneath the polyhydrated sulfate unit, but some interbedding of the two materials is tentatively observed. Hydrated materials are also present in strata exposed on the crater floor. Kaolinite, sulfates, and chlorides are observed precipitating out of terrestrial acid-saline lakes and ground waters [4], which may be analogs for the environment that deposited the materials in Columbus crater. The overall structure of the deposit is reminiscent of terrestrial "bathtub ring" evaporite deposits. Alternatively, the exposed ring could be part of a preexisting subsurface layer exposed by the impact event; however, the mineral assemblage seen here (kaolinite and polyhydrated sulfate) has not yet been observed in any other craters or intercrater bedrock exposures in the region. Further imaging and topographic data will be used to test the evaporite hypothesis by carefully examining the stratigraphic relationship between the hydrated deposits and crater wall slump blocks. The acidity and salinity implied by the observed mineral assemblage would have posed significant challenges to Martian life here, but fossils preserved in terrestrial acid-saline lake evaporites [5] suggest that sediments in Columbus may also be capable of preserving potential biosignatures until the present day. [1] Bibring, J.-P., et al. (2006), Science 312, 400-404. [2] Wray, J. J., et al. (2008), DPS 40, #03.04. [3] Swayze, G. A., et al. (2008), this conference. [4] Benison, K. C., et al. (2007), J. Sed. Res. 77, 366-388. [5] Benison, K. C., et al. (2008), Astrobiology, in press.

Wray, J. J.; Milliken, R. E.; Murchie, S. L.; Swayze, G. A.; Dundas, C. M.; Seelos, F. P.; Squyres, S. W.

2008-12-01

407

New insights into the early stages of silica-controlled barium carbonate crystallisation.  

PubMed

Recent work has demonstrated that the dynamic interplay between silica and carbonate during co-precipitation can result in the self-assembly of unusual, highly complex crystal architectures with morphologies and textures resembling those typically displayed by biogenic minerals. These so-called biomorphs were shown to be composed of uniform elongated carbonate nanoparticles that are arranged according to a specific order over mesoscopic scales. In the present study, we have investigated the circumstances leading to the continuous formation and stabilisation of such well-defined nanometric building units in these inorganic systems. For this purpose, in situ potentiometric titration measurements were carried out in order to monitor and quantify the influence of silica on both the nucleation and early growth stages of barium carbonate crystallisation in alkaline media at constant pH. Complementarily, the nature and composition of particles occurring at different times in samples under various conditions were characterised ex situ by means of high-resolution electron microscopy and elemental analysis. The collected data clearly evidence that added silica affects carbonate crystallisation from the very beginning (i.e. already prior to, during, and shortly after nucleation), eventually arresting growth on the nanoscale by cementation of BaCO3 particles within a siliceous matrix. Our findings thus shed light on the fundamental processes driving bottom-up self-organisation in silica-carbonate materials and, for the first time, provide direct experimental proof that silicate species are responsible for the miniaturisation of carbonate crystals during growth of biomorphs, hence confirming previously discussed theoretical models for their formation mechanism. PMID:25362999

Eiblmeier, Josef; Schürmann, Ulrich; Kienle, Lorenz; Gebauer, Denis; Kunz, Werner; Kellermeier, Matthias

2014-12-21

408

21 CFR 184.1143 - Ammonium sulfate.  

Code of Federal Regulations, 2010 CFR

...sulfate ((NH4 )2 SO4 , CAS Reg. No. 7783-20-2) occurs naturally and consists of colorless or white, odorless crystals or granules. It is prepared by the neutralization of sulfuric acid with ammonium hydroxide. (b) The...

2010-04-01

409

21 CFR 184.1143 - Ammonium sulfate.  

...sulfate ((NH4 )2 SO4 , CAS Reg. No. 7783-20-2) occurs naturally and consists of colorless or white, odorless crystals or granules. It is prepared by the neutralization of sulfuric acid with ammonium hydroxide. (b) The...

2014-04-01

410

21 CFR 184.1461 - Manganese sulfate.  

...manganese dioxide in sulfuric acid, and the roasting of pyrolusite (MnO2 ) ore with solid ferrous sulfate and coal, followed by leaching and crystallization. (b) The ingredient meets the specifications of the Food Chemicals Codex, 3d Ed....

2014-04-01

411

21 CFR 184.1461 - Manganese sulfate.  

Code of Federal Regulations, 2013 CFR

...manganese dioxide in sulfuric acid, and the roasting of pyrolusite (MnO2 ) ore with solid ferrous sulfate and coal, followed by leaching and crystallization. (b) The ingredient meets the specifications of the Food Chemicals Codex, 3d Ed....

2013-04-01

412

21 CFR 558.364 - Neomycin sulfate.  

Code of Federal Regulations, 2013 CFR

... Cattle, swine, sheep, and goats. For treatment and control of colibacillosis (bacterial enteritis) caused by Escherichia coli susceptible to neomycin. To provide 10 milligrams (mg) of neomycin sulfate per pound...

2013-04-01

413

21 CFR 558.364 - Neomycin sulfate.  

... Cattle, swine, sheep, and goats. For treatment and control of colibacillosis (bacterial enteritis) caused by Escherichia coli susceptible to neomycin. To provide 10 milligrams (mg) of neomycin sulfate per pound...

2014-04-01

414

21 CFR 558.364 - Neomycin sulfate.  

Code of Federal Regulations, 2011 CFR

... Cattle, swine, sheep, and goats. For treatment and control of colibacillosis (bacterial enteritis) caused by Escherichia coli susceptible to neomycin. To provide 10 milligrams (mg) of neomycin sulfate per pound...

2011-04-01

415

21 CFR 558.364 - Neomycin sulfate.  

Code of Federal Regulations, 2012 CFR

... Cattle, swine, sheep, and goats. For treatment and control of colibacillosis (bacterial enteritis) caused by Escherichia coli susceptible to neomycin. To provide 10 milligrams (mg) of neomycin sulfate per pound...

2012-04-01

416

Magnetic properties of Ni substituted Y-type barium ferrite  

NASA Astrophysics Data System (ADS)

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 (?), 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.

Won, Mi Hee; Kim, Chul Sung

2014-05-01

417

Remediation of acid mine drainage within strip mine spoil by sulfate reduction using waste organic matter  

SciTech Connect

Many treatment options for AMD, like wetlands and anoxic limestone drains, are limited by acidity, metal loadings, flow rate or areal requirements so as to be inapplicable at many sites. In-situ bacterial sulfate reduction is proposed as a solution for certain settings. Requirements for successful in-situ bacterial sulfate reduction include dissolved sulfate, an organic substrate, permanent anaerobic conditions, a mixed culture of bacteria, appropriate nutrients, and a sufficient AMD contact time. These requirements can be provided within mine spoil by injection of waste organic matter into an extensive zone of saturated spoil. Laboratory experiments on cheese whey, lactate, non-degraded sawdust, partially degraded sawdust, pulped newspaper and mushroom compost have all yielded sulfate reduction, increased alkalinity and iron sulfide precipitate in AMD with pH < 4.0. The addition of a small amount of dolomite to the organic matter creates alkaline microenvironments that facilitate the initiation of sulfate reduction. The rates of sulfate reduction using cellulose materials are slow but the rate for milk products is much more rapid. A field test utilizing partially degraded sawdust is underway. A total of 11.3 tons of sawdust mixed with 5% dolomite, 5% sewage sludge and a mixed bacterial culture was successfully injected into 4 drill holes in mine spoil as 13% w/v suspension, The spoil had enough coarse porosity for injection into the saturated subsurface at about 300 L/min, Data on in-situ SO{sub 4} reduction rates and water quality are being collected in preparation for a full remediation program at the site, which has an extensive zone of saturated spoil 10-20 m thick.

Stalker, J.; Rose, A.W.; Michaud, L.H. [Pennsylvania State Univ., University Park, PA (United States)

1996-12-31

418

Infrared determination of barium, strontium, sodium and potassium sulphates by the pellet technique.  

PubMed

Methods are proposed for the infrared determination of barium, strontium, sodium and potassium sulphates by the pellet technique. The semimicro sample is mixed with 300 mg of potassium bromide, the pellet is formed, and the peak heights are determined at the appropriate peak. Barium and strontium sulphates are measured at 983 and 993 cm(-1), respectively. Sodium and potassium sulphates are both measured at 619 cm(-1). Barium and strontium sulphates can be determined in the presence of each other in ratios from 1:20 to 20:1 from the measurements at 983 and 993 cm(-1). Carbonates or nitrates do not interfere with any of the procedures. PMID:18960911

Chasan, D E; Norwitz, G

1971-05-01

419

Using Barium Ions for Heavy-Atom Derivatization and Phasing of Xylanse ll from Trichoderma longibrachiatum  

SciTech Connect

This paper describes the use of barium chloride to produce a heavy-atom derivative of xylanase II crystals from Trichoderma longibrachiatum, which was obtained either by cocrystallization or soaking. SAD phasing led to interpretable electron-density maps that allowed unambiguous chain tracing. In the best case, with a data set collected at 9.5 keV, 88% of the residues were built, with 83% of the side chains assigned. The barium ions are found to mainly interact with main-chain carbonyl groups and water molecules. It is suggested that barium ions could also be used as a potential anomalous scatterer in the quick cryosoaking procedure for phasing.

Moiseeva,N.; Allaire, M.

2007-01-01

420

Plant sulfate assimilation genes: redundancy versus specialization  

Microsoft Academic Search

Sulfur is an essential nutrient present in the amino acids cysteine and methionine, co-enzymes and vitamins. Plants and many\\u000a microorganisms are able to utilize inorganic sulfate and assimilate it into these compounds. Sulfate assimilation in plants\\u000a has been extensively studied because of the many functions of sulfur in plant metabolism and stress defense. The pathway is\\u000a highly regulated in a

Stanislav Kopriva; Sarah G. Mugford; Colette Matthewman; Anna Koprivova

2009-01-01

421

Sulfation in lead–acid batteries  

Microsoft Academic Search

Virtually, all military land vehicle systems use a lead–acid battery to initiate an engine start. The maintainability of these batteries and as a consequence, system readiness, has suffered from a lack of understanding of the reasons for battery failure. Often, the term most commonly heard for explaining the performance degradation of lead–acid batteries is the word, sulfation.Sulfation is a residual

Henry A. Catherino; Fred F. Feres; Francisco Trinidad

2004-01-01

422

Sulfate induced heave in lime stabilized soil  

E-print Network

Bo Conchsion Ccnctrsicn Sulfates other salts InterreUve conctertons Figure 1 Schematic Outline of Testing and Reporting Procedure CHAPTER II LITERATURE REVIEW Introduction The thesis of this study is that electrical conductivity of soils can be related...Bo Conchsion Ccnctrsicn Sulfates other salts InterreUve conctertons Figure 1 Schematic Outline of Testing and Reporting Procedure CHAPTER II LITERATURE REVIEW Introduction The thesis of this study is that electrical conductivity of soils can be related...

Bredenkamp, Sanet

2012-06-07

423

Climate forcing by carbonaceous and sulfate aerosols  

Microsoft Academic Search

An atmospheric general circulation model is coupled to an atmospheric chemistry model to calculate the radiative forcing\\u000a by anthropogenic sulfate and carbonaceous aerosols. The latter aerosols result from biomass burning as well as fossil fuel\\u000a burning. The black carbon associated with carbonaceous aerosols is absorbant and can decrease the amount of reflected radiation\\u000a at the top-of-the-atmosphere. In contrast, sulfate aerosols

J. E. Penner; C. C. Chuang; K. Grant

1998-01-01

424

Calcium sulfate veins characterized by ChemCam/Curiosity at Gale crater, Mars  

NASA Astrophysics Data System (ADS)

Curiosity rover has analyzed abundant light-toned fracture-fill material within the Yellowknife Bay sedimentary deposits. The ChemCam instrument, coupled with Mastcam and ChemCam/Remote Micro Imager images, was able to demonstrate that these fracture fills consist of calcium sulfate veins, many of which appear to be hydrated at a level expected for gypsum and bassanite. Anhydrite is locally present and is found in a location characterized by a nodular texture. An intricate assemblage of veins crosses the sediments, which were likely formed by precipitation from fluids circulating through fractures. The presence of veins throughout the entire ~5 m thick Yellowknife Bay sediments suggests that this process occurred well after sedimentation and cementation/lithification of those sediments. The sulfur-rich fluids may have originated in previously precipitated sulfate-rich layers, either before the deposition of the Sheepbed mudstones or from unrelated units such as the sulfates at the base of Mount Sharp. The occurrence of these veins after the episodes of deposition of fluvial sediments at the surface suggests persistent aqueous activity in relatively nonacidic conditions.

Nachon, M.; Clegg, S. M.; Mangold, N.; Schröder, S.; Kah, L. C.; Dromart, G.; Ollila, A.; Johnson, J. R.; Oehler, D. Z.; Bridges, J. C.; Le Mouélic, S.; Forni, O.; Wiens, R. C.; Anderson, R. B.; Blaney, D. L.; Bell, J. F.; Clark, B.; Cousin, A.; Dyar, M. D.; Ehlmann, B.; Fabre, C.; Gasnault, O.; Grotzinger, J.; Lasue, J.; Lewin, E.; Léveillé, R.; McLennan, S.; Maurice, S.; Meslin, P.-Y.; Rapin, W.; Rice, M.; Squyres, S. W.; Stack, K.; Sumner, D. Y.; Vaniman, D.; Wellington, D.

2014-09-01

425

Precipitation Estimates, Part 1: Measurement  

NSDL National Science Digital Library

This is part one of a two-module series on estimation of observed precipitation. Through use of rich illustrations, animations, and interactions, this module provides an overview of the science of precipitation estimation using various measuring platforms. First, we define quantitative precipitation estimation (QPE) and examine technologies for remote sensing of QPE, including radar and satellite and the strengths and limitations of each. That is followed by an examination of the use of rain gauges for precipitation estimation and important issues to consider with rain gauge measurement. Finally we provide an introduction to the strengths and limitations of using precipitation climatology for QPE including PRISM.

Comet

2009-06-03

426

Distribution of sulfate between phases in Portland cement clinkers  

Microsoft Academic Search

Sulfate can occur in Portland cement clinkers as alkali sulfates, potassium calcium sulfate (calcium langbeinite), anhydrite, and as a substituent in the major phases, especially alite and belite. Data for the contents in alite and belite are reviewed and relations to bulk clinker composition are discussed. Evidence on sulfate distribution from extraction procedures is similarly considered. A procedure for predicting

H. F. W. Taylor; H. F. W

1999-01-01

427

Inactivation of Thrombin by a Fucosylated Chondroitin Sulfate from Echinoderm  

Microsoft Academic Search

A polysaccharide extracted from the sea cucumber body wall has the same backbone structure as the mammalian chondroitin sulfate, but some of the glucuronic acid residues display sulfated fucose branches. These branches confer high anticoagulant activity to the polysaccharide. Since the sea cucumber chondroitin sulfate has analogy in structure with mammalian glycosaminoglycans and sulfated fucans from brown algae, we compared

Paulo A. S Mourão; Catherine Boisson-Vidal; Jacqueline Tapon-Bretaudière; Bruno Drouet; Andrée Bros; Anne-Marie Fischer

2001-01-01

428

Raman study of barium titanate with oxygen vacancies  

NASA Astrophysics Data System (ADS)

Barium titanate (BaTiO 3) crystal samples with different distribution of oxygen vacancies were prepared through different thermal treatment processes. The influences of oxygen vacancies on the Raman spectra and X-ray photoelectron spectroscopy (XPS) spectra of BaTiO 3 single crystals were studied comparatively. Raman measurements of fast-cooled BaTiO 3, which annealed in vacuum and then cooled in air showed many different spectroscopic results comparing with as-received BaTiO 3 sample. Raman measurements of slow-cooled BaTiO 3, which annealed in vacuum and then cooled in tube furnace exhibited few spectroscopic differences. XPS measurements of as-received BaTiO 3 sample and fast-cooled BaTiO 3 sample confirmed that this discrepancy resulted from the surface phase of oxygen vacancy in BaTiO 3.

Zhang, W. H.; Chen, L.; Tao, Y. T.; Zhang, W. H.; Chen, J.; Zhang, J. X.

2011-12-01

429

Calcium barium niobate ridge waveguide on silicon substrate  

NASA Astrophysics Data System (ADS)

A novel optical ridge waveguide using calcium barium niobate (CBN) with a high electro-optic coefficient on silicon substrate is proposed for the design and realization of the next-generation hybrid modulators with short length and low driving voltage. To overcome the etching difficulty of CBN, the design of a waveguide, including an elevated CBN layer based on etched silicon dioxide, is presented. Fabrication of a thick 2.5-?m CBN layer is performed using pulsed laser deposition. Deposited silicon dioxide on the sides and top of the CBN reduces the waveguide loss as low as 3.44 dB/cm, measured using a cutback method. Good agreement between the mode profiles of the simulation and measurement is obtained.

Mortazy, Ebrahim; Stateikina, Irina; Tehranchi, Amirhossein; Delprat, Sébastien; Chaker, Mohamed; Wu, Ke

2010-07-01

430

Dynamics of the CRRES barium releases in the magnetosphere  

NASA Technical Reports Server (NTRS)

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.

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

431

Nonlinear spectroscopy of barium in parallel electric and magnetic fields  

NASA Astrophysics Data System (ADS)

We report on the experimental spectral observations of barium in parallel electric and magnetic fields. The laser pulse is linearly polarized along or perpendicular to the fields, leading to the states m = 0 and the states m = ±1 populated, respectively, by one photon excitation. By sweeping the electric field, we observe the linear and nonlinear splitting of the diamagnetic spectrum as the electric field increases. The spectral anticrossing is induced by the atomic core effect. The Stark spectrum also shows an obvious nonlinear quadratic behavior when the applied magnetic field varies strongly. All spectra are well explained by the full quantum calculation after taking the quantum defect effects of the channel ns up to nf into account.

Yang, Hai-Feng; Gao, Wei; Cheng, Hong; Liu, Hong-Ping

2014-10-01

432

Negative-U extended Hubbard model for doped barium bismuthates  

NASA Astrophysics Data System (ADS)

We present detailed mean-field and random-phase-approximation studies of the negative-U, extended Hubbard model with a view to understanding the properties of the doped barium bismuthates. In particular, we obtain the phase diagram, the excitation spectrum, and the optical conductivity in the semiconducting phase of the bismuthates. We show by explicit calculations how this model leads to a natural explanation for the two, well-separated transport and optical gaps observed in the semiconducting phases of the bismuthates. We fix the parameters in our model by fitting these experimentally observed gaps; and with these parameter values we compute other properties of these systems. We also show how metallic screening and disorder can decrease the superconducting Tc dramatically. Our theory leads to an exotic charge-transport mechanism, dominated by charge +/-2e bosons (cooperons), in the semiconducting phases of these systems.

Taraphder, A.; Krishnamurthy, H. R.; Pandit, Rahul; Ramakrishnan, T. V.

1995-07-01

433

Barium titanate nanocomposite capacitor FY09 year end report.  

SciTech Connect

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.

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

434

Studies on immobilization of thorium in barium borosilicate glass  

NASA Astrophysics Data System (ADS)

The barium borosilicate glass (BBS) matrix has shown considerable solubility of ThO 2 at 1000 °C. As seen by X-ray diffractometry (XRD) and Electron probe micro analysis (EPMA) up to 15.86 wt% of ThO 2 could be dissolved in this matrix. The homogeneity of thoria loaded glass was convincingly ascertained by EPMA. Attempts to load more than 16 wt% ThO 2 led to the phase separation of crystalline phases identified as major phase of ThO 2 and minor percentage of ThSiO 4 phase with altogether different morphologies, as seen by XRD. Interestingly, the back scattered images of thorite crystals point towards the presence of chemical zoning. The results being reported in this paper are of interest especially with respect to immobilization of other actinides in borosilicate glass matrix.

Mishra, R. K.; Sengupta, Pranesh; Kaushik, C. P.; Tyagi, A. K.; Kale, G. B.; Raj, Kanwar

2007-02-01

435

A new type of microphone using flexoelectric barium strontium titnate  

NASA Astrophysics Data System (ADS)

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 ?m×50 ?m 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.

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

2014-03-01

436

Communication: Barium ions and helium nanodroplets: Solvation and desolvation  

NASA Astrophysics Data System (ADS)

The solvation of Ba+ 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 2P1/2 ? 6s 2S1/2 and 6p 2P3/2 ? 6s 2S1/2 transitions of Ba+ 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+ ions, these are being ejected from the helium droplets either as bare Ba+ ions or as small Ba+Hen (n < 20) complexes.

Zhang, Xiaohang; Drabbels, Marcel

2012-08-01

437

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

NASA Astrophysics Data System (ADS)

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.

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

1997-08-01

438

SBN60, strontium-barium niobate at 100?K  

PubMed Central

The title compound, Sr0.6Ba0.4Nb2O6 (strontium barium niobium oxide), belongs to the group of strontium–barium niobates with varying composition of Sr and Ba. Their general formula can be written as SrxBa1 - xNb2O6. Below the Curie temperature, T c, these materials indicate ferroelectric properties. The Curie temperature for SBN60 is equal to 346±0.5?K so the structure is in the ferroelectric phase at the measurement temperature of 100?K. Characteristic for this family of compounds is the packing along the z-axis. The NbO6 corner-sharing octa­hedra surround three types of vacancy tunnels with penta­gonal, square and triangular shapes. The Sr2+ ions partially occupy two unique sites, the first one located inside the penta­gon and the second one in the square tunnels. Consequently, they are situated on the mirror plane and the inter­section of two glide planes, respectively. The site inside the penta­gonal tunnel is additionally disordered so that the same position is shared by Ba2+ and Sr2+ ions whereas another part of the Ba2+ ion occupies a different position (relative occupancies 0.43:0.41:0.16). One of the NbV atoms and three of the O2? ions occupy general positions. The second NbV atom is located on the inter­section of the mirror planes. Two remaining O2? ions are located on the same mirror plane. Only the NbV atom and one of the O2? ions which is located on the mirror plane are not disordered. Each of the remaining O2? ions is split between two sites, with relative occupancies of 0.52:0.48 (O2? ions in general positions) and 0.64:0.36 (O2? ion on the mirror plane). PMID:24098159

Stachowicz, Marcin; Gawryszewska, Olga; Swirkowicz, Marek A.; Lukasiewicz, Tadeusz

2013-01-01

439

Precipitation of Dolomite in Aerobic Culture Experiments Using Halophilic Bacteria  

NASA Astrophysics Data System (ADS)

The study of carbonate biomineralization in hypersaline environments provides information about the key role microorganisms have played in global carbon cycling, especially in the Precambrian. Recently, a microbial dolomite model was proposed based on the study of a hypersaline coastal lagoon, Lagoa Vermelha, Rio de Janeiro (Brazil). This model suggests that sulfate-reducing bacteria mediate dolomite precipitation by increasing pH and removing the sulfate inhibitor. The anoxic conditions of this system may not, however, apply to all ancient dolomite formation. Dolomite is an abundant carbonate mineral found widespread in the geological record in a variety of environmental settings. Thus, a single microbial dolomite model probably cannot explain its widespread distribution and a broad spectrum of conditions may be linked with its formation. In contrast to Lagoa Vermelha, Brejo do Espinho, a shallow hypersaline lagoon located in the same region, is a dolomite-forming environment with oxic bottom conditions. The sediment comprises primarily high Mg-calcite and Ca-dolomite. Heterotrophic microorganisms have been isolated from algal mats growing in Brejo do Espinho, and biomineralization experiments have been conducted at variable temperatures (15, 20, 25, 30, 35 and 40° C) and salinities (sea water and 2x seawater) to simulate the natural environmental conditions. After a 20-day incubation period, several aerobic culture experiments have crystal growth of Ca-dolomite and high Mg-calcite. Our study demonstrates that, under aerobic conditions, heterotrophic microorganisms can mediate dolomite precipitation. These results indicate that microbial dolomite precipitation is not necessarily linked to any particular group of organisms or specific metabolic processes or even a specific environment, i.e., it is not exclusively an anoxic mineral but can be precipitated in the presence of oxygen. This has implications for the distribution of dolomite in the geologic record.

Roman, M. S.; Vasconcelos, C.; McKenzie, J. A.

2003-12-01

440

A novel electrostatic precipitator  

NASA Astrophysics Data System (ADS)

ESP (Electrostatic Precipitation) has been widely used in the mining, building materials, metallurgy and power industries. Dust particles or other harmful particles from the airstream can be precipitated by ESP with great collecting efficiency. Because of its' large size, high cost and energy consumption, the scope of application of ESP has been limited to a certain extent. By means of the theory of electrostatics and fluid dynamics, a corona assembly with a self-cleaning function and a threshold voltage automatic tracking technology has been developed and used in ESP. It is indicated that compared with conventional ESP, the electric field length has been reduced to 1/10 of the original, the current density on the collecting electrode increased 3-5 times at the maximum, the approach speed of dust particles in the electric field towards the collecting electrode is 4 times that in conventional ESP and the electric field wind speed may be enhanced by 2-3 times the original. Under the premise of ESP having a high efficiency of dust removal, equipment volume may be actually reduced to 1/5 to 1/10 of the original volume and energy consumption may be reduced by more than 50%.

Tang, Minkang; Wang, Liqian; Lin, Zhigui

2013-03-01

441

The Global Precipitation Climatology Project (GPCP) Combined Precipitation Dataset  

NASA Technical Reports Server (NTRS)

The Global Precipitation Climatology Project (GPCP) has released the GPCP Version 1 Combined Precipitation Data Set, a global, monthly precipitation dataset covering the period July 1987 through December 1995. The primary product in the dataset is a merged analysis incorporating precipitation estimates from low-orbit-satellite microwave data, geosynchronous-orbit -satellite infrared data, and rain gauge observations. The dataset also contains the individual input fields, a combination of the microwave and infrared satellite estimates, and error estimates for each field. The data are provided on 2.5 deg x 2.5 deg latitude-longitude global grids. Preliminary analyses show general agreement with prior studies of global precipitation and extends prior studies of El Nino-Southern Oscillation precipitation patterns. At the regional scale there are systematic differences with standard climatologies.

Huffman, George J.; Adler, Robert F.; Arkin, Philip; Chang, Alfred; Ferraro, Ralph; Gruber, Arnold; Janowiak, John; McNab, Alan; Rudolf, Bruno; Schneider, Udo

1997-01-01

442

The Global Precipitation Climatology Project (GPCP) combined precipitation dataset  

SciTech Connect

The Global Precipitation Climatology Project (GPCP) has released the GPCP Version 1 Combined Precipitation Data Set, a global, monthly precipitation dataset covering the period July 1987 through December 1995. The primary product in the dataset is a merged analysis incorporating precipitation estimates from low-orbit-satellite microwave data, geosynchronous-orbit-satellite microwave data, geosynchronous-orbit-satellite infrared data, and rain gauge observations. The dataset also contains the individual input fields, a combination of the microwave and infrared satellite estimates, and error estimates for each field. The data are provided on 2.5{degrees} x 2.5{degrees} latitude-longitude global grids. Preliminary analyses show general agreement with prior studies of global precipitation and extends prior studies of El Nino-Southern Oscillation precipitation patterns. At the regional scale there are systematic differences with standard climatologies.

Huffman, G.J. [NASA/GSFC Laboratory for Atmospheres, Greenbelt, MD (United States)] [NASA/GSFC Laboratory for Atmospheres, Greenbelt, MD (United States); [Science Systems and Applications, Inc., Greenbelt, MD (United States); Arkin, P.; Janowiak, J. [NASA/GSFC Laboratory for Atmospheres, Greenbelt, MD (United States)] [and others] [NASA/GSFC Laboratory for Atmospheres, Greenbelt, MD (United States); and others

1997-01-01

443

Growth, Characterization and Applications of Beta-Barium Borate and Related Crystals.  

National Technical Information Service (NTIS)

Emphasis of our program during the past year has been on improving the size and quality of beta-barium borate (BBO) crystal, develop the growth recipe for lithium triborate crystal (LBO), characterization of LBO, develop BBO optical parametric oscillators...

C. L. Tang

1991-01-01

444

Barium Titanate Nanoparticles as Exogenous Contrast Agents in Second Harmonic Optical Coherence Tomography  

E-print Network

I propose and demonstrate a method by which barium titanate nanoparticle clusters can be used as exogenous contrast agents in Second Harmonic Optical Coherence Tomography imaging systems to localize and highlight desired regions of tissue. SH...

Pearson, Jeremy T

2013-05-06

445

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

NASA Technical Reports Server (NTRS)

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.

Swift, D. W.

1985-01-01

446

Deriving a History of Deposition and Alteration from Phyllosilicate-Sulfate Associations at Gale Crater  

NASA Astrophysics Data System (ADS)

Gale Crater, field site for the 2011 Mars Science Laboratory rover Curiosity, is located in one of the most chlorine- and sulfur-rich areas detected by Odyssey gamma-ray spectroscopy (GRS) along the dichotomy boundary between Mars' southern cratered highlands and the northern plains. Comparably elevated chlorine and sulfur abundances occur in Arabia Terra, where modeling and MER Opportunity observations suggest that groundwater upwelling led to evaporite salt precipitation. In a deep crater such as Gale upwelling may have produced playa systems. High GRS sulfur at Gale Crater is supported by visible-infrared spectra in Gale's central mound consistent with Mg-sulfates (kieserite and polyhydrated), interstratified with smectite. There is a significant (~20 m) section with abundant nontronite and little or no evidence of hydrated sulfate in the lower mound. Mineral stratification at Gale promises the possibility of capturing a transition in sedimentary environment between phyllosilicate- and sulfate-dominated deposition. Sedimentary fabrics, textures, and mineralogy all bear on determining sedimentary history and Gale will provide an exceptionally detailed history through Curiosity's instrument suite. Should the clay minerals at Gale be limited to nontronite and other smectites, with little evidence of chlorite or mixed layer chlorite/smectite, limits can be placed on the extent of interaction with Mg-sulfate solutions. Gale has evidence of being at one time completely filled and a lack of chloritic forms would be particularly limiting on occurrence and composition of paleo-groundwater. Complete infilling of Gale would likely result in past burial temperatures, at the deep elevation of the landing site, favoring chloritization of smectite if concentrated Mg-sulfate groundwater were present. Sedimentary history at Gale may be further constrained by absence or presence of Ca-sulfates, which should form by cation exchange between smectite and Mg-enriched brines if the two were in communication. Since Mg-sulfate solutions are implicated by presence of Mg-sulfates at Gale, absence or presence of Ca-sulfates may be a measure of hydrologic isolation or interaction, respectively, within and between stratigraphic horizons. The forms in which Ca-sulfates may occur (gypsum, bassanite, or anhydrite) would provide further constraints on Gale's history of deposition and alteration. The high solubility of Mg-sulfates can also place limits on interpretations of post-depositional alteration by groundwater, wherein preservation of primary depositional structure, fabric, and mineralogy will be an especially sensitive marker of deposits undisturbed by such alteration. Groundwater, snowmelt, and surface water are all capable of attacking Mg-sulfate (and potential halide) deposits at Gale but so too will elevated water vapor pressure that may lead to deliquescence or efflorescence, effects that may be expected if episodes of high obliquity allowed prolonged frost or ice accumulation in Gale Crater. Among the concerns of Curiosity will be identification and sampling of sedimentary strata that are as pristine as possible. The sensitivity of phyllosilicate-sulfate associations to transformation promises that evidence of alteration will be identifiable.

Vaniman, D. T.

2011-12-01

447

Chronic barium intoxication disrupts sulphated proteoglycan synthesis: a hypothesis for the origins of multiple sclerosis.  

PubMed

High level contamination by natural and industrial sources of the alkali earth metal, barium (Ba) has been identified in the ecosystems/workplaces that are associated with high incidence clustering of multiple sclerosis (MS) and other neurodegenerative diseases such as the transmissible spongiform encephalopathies (TSEs) and amyotrophic lateral sclerosis (ALS). Analyses of ecosystems supporting the most renowned MS clusters in Saskatchewan, Sardinia, Massachusetts, Colorado, Guam, NE Scotland demonstrated consistently elevated levels of Ba in soils (mean: 1428 ppm) and vegetation (mean: 74 ppm) in relation to mean levels of 345 and 19 ppm recorded in MS-free regions adjoining. The high levels of Ba stemmed from local quarrying for Ba ores and/or use of Ba in paper/foundry/welding/textile/oil and gas well related industries, as well as from the use of Ba as an atmospheric aerosol spray for enhancing/refracting the signalling of radio/radar waves along military jet flight paths, missile test ranges, etc. It is proposed that chronic contamination of the biosystem with the reactive types of Ba salts can initiate the pathogenesis of MS; due to the conjugation of Ba with free sulphate, which subsequently deprives the endogenous sulphated proteoglycan molecules (heparan sulfates) of their sulphate co partner, thereby disrupting synthesis of S-proteoglycans and their crucial role in the fibroblast growth factor (FGF) signalling which induces oligodendrocyte progenitors to maintain the growth and structural integrity of the myelin sheath. Loss of S-proteoglycan activity explains other key facets of MS pathogenesis; such as the aggregation of platelets and the proliferation of superoxide generated oxidative stress. Ba intoxications disturb the sodium-potassium ion pump--another key feature of the MS profile. The co-clustering of various neurodegenerative diseases in these Ba-contaminated ecosystems suggests that the pathogenesis of all of these diseases could pivot upon a common disruption of the sulphated proteoglycan-growth factor mediated signalling systems. Individual genetics dictates which specific disease emerges at the end of the day. PMID:15082100

Purdey, Mark

2004-01-01

448

Preparation of polyethylene sacks for collection of precipitation samples for chemical analysis  

USGS Publications Warehouse

Polyethylene sacks are used to collect precipitation samples. Washing polyethylene with acetone, hexane, methanol, or nitric acid can change the adsorptive characteristics of the polyethylene. In this study, simulated precipitation at pH 4.5 was in contact with the polyethylene sacks for 21 days; subsamples were removed for chemical analysis at 7, 14, and 21 days after intitial contact. Sacks washed with acetone adsorbed iron and lithium; sacks washed with hexane adsorbed barium, iron , and lithium; sacks washed with methanol adsorbed calcium and iron; and sacks washed with 0.30 N nitric acid adsorbed iron. Leaching the plastic sacks with 0.15 N nitric acid did not result in 100-percent recovery of any of the adsorbed metals. Washing polyethylene sacks with dilute nitric acid caused the pH of the simulated precipitation to be decreased by 0.2 pH unit after 1 week of contact with the polyethylene. The specific conductance increased by 10 microsiemens per centimeter. Contamination of precipitation samples by lead was determined to be about 0.1 microgram per liter from contact with precleaned polyethylene sacks. No measurable contamination of precipitation samples by zinc occurred. (USGS)

Schroder, L.J.; Bricker, A.W.

1985-01-01

449

Amphorous hydrated Fe(III) sulfate: metastable product and bio-geochemical marker of iron oxidizing thiobacilli  

NASA Astrophysics Data System (ADS)

Chemolithotrophic iron oxidation by Thiobacillus ferrooxidans and other iron oxidizing thiobacilli produce an Fe(III) sulfato complex that polymerizes as x-ray amorphous filaments approximately 40 nm in diameter. The precursor complex in solutionis seen by ATR-FTIR spectroscopy to have a sulfate spectrum resembling the v(subscript 3) and v(subscript 1) vibrational modes of the precipitated polymer. Chemically similar precipitates prepared by oxidation of acid ferrous sulfate with hydrogen peroxide have a different micromorphology, higher iron/sulfur ratio and acid solubility than the bacterial product. They possess coalescing globular microstructures composed of compacted micro-fibrils. Scanning electron microscopy and diffuse reflectance FTIR show the formation of iron polymer on the surface of immobilized cells of T. ferrooxidans, oxidizing iron during the corrosion of steel. Although spatially separated form the steel coupons by a membrane filter, the cell walls become covered with tufts of amorphous hydrated Fe(III) sulfate. The metastable polymer is converted to crystalline goethite, lepidocrocite, and magnetite in that order, as the pH rises due to proton reduction at cathodic sites on the steel. The instability of the iron polymer to changes in pH is also evidenced by the loss of sulfate when washed with lithium hydroxide solution at pH 8. Under those conditions there is little change in micromorphology, but restoration of sulfate with sulfuric acid at pH 2.5, fails to re-establish the original chemical structure. Adding sulfate salts of appropriate cations to solutions of the Fe(III) sulfato complex or suspensions of its precipitated polymer in dilute sulfuric acid, result in dissociation of the metastable complex followed by crystallization of ferric ions and sulfate in jarosites. Jarosites and other derivatives of iron precipitation by iron oxidizing thiobacilli, form conspicuous deposits in areas of natural pyrite leaching. The role of iron oxidizing thiobacilli in pyrite leaching, biohydrometallurgy, acid mine drainage, and the cycle of iron and sulfur in nature, has been studied for nearly 50 years. The manifestation of those activities, so widespread on Earth, can be a clue for seeking evidence of life elsewhere.

Lazaroff, Norman; Jollie, John; Dugan, Patrick R.

1998-07-01

450

Estimating historical in-lake alkalinity generation from sulfate reduction and its relationship to lake chemistry as inferred from algal microfossils  

Microsoft Academic Search

Sediment cores were used to estimate in-lake alkalinity generation resulting from sulfate reduction relative to inferred changes in lakewater pH and trophic status over the last century in three Connecticut lakes. Despite being situated in geological settings with crystalline bedrock and thin, poorly buffered soils, and being impacted with high rates of acidic precipitation, none of the study lakes have

Peter A. Siver; Richard Ricard; Richard Goodwin; Anne E. Giblin

2003-01-01

451

Oxygen isotopic fractionation during bacterial sulfate reduction  

NASA Astrophysics Data System (ADS)

Sulfur isotope fractionation during bacterial sulfate reduction (BSR) is understood to depend on a variety of environmental parameters, such as sulfate concentration, temperature, cell specific sulfate reduction rates, and the carbon substrate. What controls oxygen isotope fractionation during BSR is less well understood. Some studies have suggested that carbon substrate is important, whereas others concluded that there is a stoichiometric relationship between the fractionations of sulfur and oxygen during BSR. Studies of oxygen fractionation are complicated by isotopic equilibration between sulfur intermediates, particularly sulfite, and water. This process can modify the isotopic composition of the extracellular sulfate pool (?18OSO4 ). Given this, the challenge is to distinguish between this isotopic equilibration and fractionations linked to the kinetic effects of the intercellular enzymes and the incorporation of sulfate into the bacterial cell. The ?18OSO4 , in concert with the sulfur isotope composition of sulfate (?34SSO4), could be a powerful tool for understanding the pathways and environmental controls of BSR in natural systems. We will present ?18OSO4 data measured from batch culture growth of 14 different species of sulfate reducing bacteria for which sulfur isotope data were previously published. A general observation is that ?18OSO4 shows little isotopic change (<4‰) even when the ?34SSO4 varies by up to 30 to 50‰ over the course of the experiment. This disparity could reflect little to no kinetic effect during BSR and/or equilibration between sulfur intermediates and the isotopically light water (~-5‰) of the growth medium. Our present batch culture data do not allow us to convincingly isolate the magnitude and the controlling parameters of the kinetic isotope effect for oxygen. However, ongoing growth of mutant bacteria missing enzymes critical in the different steps of BSR may assist in this mission.

Balci, N.; Turchyn, A. V.; Lyons, T.; Bruchert, V.; Schrag, D. P.; Wall, J.

2006-12-01

452

Diurnal precipitation cycle in Austria  

NASA Astrophysics Data System (ADS)

A back-trajectory clustering method was developed to identify synoptic patterns associated with heavy precipitation in Austria. Extending this work from daily precipitation sums to accumulation intervals from 12 to 48 hours, an unexpected problem was encountered related to the observation schedule of data. To modify available data to our specific needs, evening precipitation falling between 19 and 21 LT (Local Time) was studied. Hourly precipitation data for the period of 1950 to 2005 from 132 weather stations over Austria were used. It was found that the evening precipitation fraction has its maxima in the central Alps in all seasons, except in autumn when maxima shift more towards the south of the Alps. These results encouraged us to analyse the variation of diurnal precipitation for different seasons in Austria as well. A total of 119 stations with sixteen years (1990-2005) of data were used for this purpose. Mean hourly precipitation values were calculated, which were then normalised, smoothed and were finally clustered to find regions with homogeneous diurnal cycles. The diurnal cycles of precipitation of the centres exhibit systematic patterns and seasonal cycles, reflecting intensity and timing of convective activity over these regions. The winter season is relatively dry and summer is associated with the highest precipitation. The areas inside the Alps receive higher amplitudes of precipitation in summer. Interesting features such as bimodal distributions, nocturnal maxima and early morning maxima were also observed in many regions.

Yaqub, Asma; Seibert, Petra; Formayer, Herbert

2011-01-01

453

Preparation, characterization and magnetic properties of the doped barium hexaferrites BaFe12-2xCox/2Znx/2SnxO19, x=0.0-2.0  

NASA Astrophysics Data System (ADS)

A series of powders of M-typed barium hexaferrites doped with Co, Zn and Sn of general formula BaFe12-2xCox/2Znx/2SnxO19 (x=0-2.0) were prepared by the co-precipitation/molten salt method. The structures, particle morphology and magnetic properties of the products were characterized by X-ray powder diffraction, vibrating sample magnetometer and ESEM/EDX. The results show that the crystallinity of the samples decreases with increase in the doping amount x. When x is less than 0.6, it is possible to obtain perfectly crystallized hexagonal BaFe12-2xCox/2Znx/2SnxO19, where the diameters of the particles are around 500 nm. The saturation magnetization of pure barium ferrite BaFe12O19 produced with this method is 71.9 A m2 kg-1 at room temperature and the intrinsic coercivity (Hc) is 367.8 kA m-1. The doped barium hexaferrite powder obtained when x is between 0.3 and 0.4 exhibits high saturation magnetization and a temperature dependence of coercivity close to zero.

Liu, Ying; Drew, Michael G. B.; Liu, Yue; Wang, Jingping; Zhang, Milin

2010-04-01

454

A revised isotope fractionation model for dissimilatory sulfate reduction in sulfate reducing bacteria  

Microsoft Academic Search

Sulfur isotope fractionation during dissimilatory sulfate reduction has been conceptually described by the widely accepted Rees model as related to the stepwise reduction of sulfate to sulfide within the cells of bacteria. The magnitude of isotope fractionation is determined by the interplay between different reduction steps in a chain of reactions. Here we present a revision of Rees’ model for

Benjamin Brunner; Stefano M. Bernasconi

2005-01-01

455