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1

Reduced discrete population balance model for precipitation of barium sulfate nanoparticles in non-ionic microemulsions  

Microsoft Academic Search

A discrete population balance model is formulated in order to analyze the precipitation process of barium sulfate nanoparticles taking place in the droplets of a water-in-oil microemulsion. The model accounts for the distribution of reactants over the droplet population in terms of discrete numbers of the reacting ionic species (Ba2+, SO42?), as well as for the nucleation and growth of

Björn Niemann; Kai Sundmacher

2008-01-01

2

Precipitation of barium sulfate: Experimental investigation about the influence of supersaturation and free lattice ion ratio on particle formation  

Microsoft Academic Search

The precipitation of barium sulfate from aqueous solutions of barium chloride and sodium sulfate was investigated experimentally in a continuous Y-Mixer to avoid any mixing influence. Initial supersaturation and the initial ratio R=cBafree2+\\/cSO4,free2? of the free lattice ions after complete educt mixing were varied over a broad range. The variation of the free lattice ions has a strong influence on

Martin Kucher; Danijel Babic; Matthias Kind

2006-01-01

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  

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

6

BETA RADIATION SELF ABSORPTION OF PRECIPITATES COLLECTED ON FILTER PAPER STUDIES WITH S³⁵-BARIUM SULFATE  

Microsoft Academic Search

In determining the specific activity of S³⁵ precipitated as ry to ; make corrections for absorption and scattering of beta emission. Different ; yields of precipitate and different types of self-absorption curves were obtained ; when S³⁵ was precipitated as BaSOâ in the presence and absence of ; salt. An equation was derived for expressing the self absorption of precipitates

R. G. Gottschalk; H. Hoch; G. H. Stidworthy

1962-01-01

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

Hierarchically nanostructured barium sulfate fibers.  

PubMed

BaSO(4) nanostructures with controlled morphologies were successfully produced via one-step process through precipitation of BaSO(4) in aqueous and organic media. The synthesis is carried out by mixing solutions of BaCl(2) and Na(2)SO(4) in presence of EDTA (disodium ethylenediaminetetraacetic acid) at room temperature. The influence of the reaction conditions such as initial reactants concentration, pH, EDTA/[Ba(2+)] ratio and aging on the BaSO(4) nanoparticles organization is studied. Using EDTA in aqueous media, spherical secondary particles of 500 nm diameter are obtained, which are formed by 4 nm size primary particles. With dimethyl sulfoxide and small amounts of water (5%) and EDTA, the aging process allows the production of long homogeneous fibers, related to hierarchical organization of BaSO(4) nanoparticles. Direct observation of self-assembling of primary particles by HRTEM allows proposing a mechanism for fiber formation, which is based on multipolar attractions that lead to a brick-by-brick organization along a preferential orientation. Results evidence the role of EDTA as controlling agent of the morphology and primary and secondary mean particle size. PMID:20055367

Romero-Ibarra, Issis C; Rodríguez-Gattorno, Geonel; García-Sánchez, Mario F; Sánchez-Solís, Antonio; Manero, Octavio

2010-05-18

9

Coprecipitation of radium with barium sulfate from salt solutions  

Microsoft Academic Search

Coprecipitation of radium with barium sulfate from highly concentrated NaCl solutions is studied, including the effects of\\u000a the initial solution composition, alkaline reagent (CaO, NaOH), supporting electrolyte (NaCl) concentration, and pH. The process\\u000a is promoted by high NaCl concentration in the initial solution, which is due to structural transformation and change in the\\u000a sorption activity of the BaSO4 precipitate in

Yu. P. Kudryavskii; O. V. Rakhimova

2007-01-01

10

Coprecipitation of uranium and thorium with barium sulfate  

Microsoft Academic Search

The coprecipitation behaviour of uranium or thorium with barium sulfate is investigated from the variation of yields with uranium or thorium concentration, acid and acidity, and amount of sodium and\\/or potassium sulfate. Uranium or thorium in quantities less than 1.5 mg is quantitatively coprecipitated with barium (5.9 mg) sulfate when using an optimum conditions. The chemical form of uranium in

T. Kimura; Y. Kobayashi

1985-01-01

11

Coprecipitation of radium with barium sulfate from calcium-containing solutions  

SciTech Connect

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 amount of sulfuric acid to the sum of the amounts of barium, calcium, and magnesium, the influence of this factor on the degree of radium precipitation being negative: the radioactivity of the filtrate intensifies. This deviation from the mechanisms of radium coprecipitation in pure solutions has been explained by the phenomenon of blocking of the carrier surface by the calcium sulfate crystals.

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

1988-11-01

12

Modeling and minimization of barium sulfate scale  

Treesearch

Barium carbonate dissolves in the bleach plant when the pH drops below 7 and, if barium and ... at higher pH, but this will work only in mills where calcium scales are not a concern. A third option is to use crystal modifiers (scale inhibitors).

13

Radiation dose in mass screening for gastric cancer with high-concentration barium sulfate compared with moderate-concentration barium sulfate.  

PubMed

Recently, high-concentration barium sulfate has been developed and is used in many medical facilities. This study compared radiation dose using high-concentration and moderate-concentration barium sulfate. The dose was evaluated with an experimental method using a gastric phantom and with a clinical examination. In the former, the dose and X-ray tube load were measured on the phantom with two concentrations of barium sulfate. In the latter, the fluoroscopic dose-area product (DAP), the radiographic DAP and their sum, the total DAP, were investigated in 150 subjects (112 males, 38 females) treated with both concentrations of barium sulfate. The effective dose was calculated by the software of PCXMC in every case. The results of the experimental evaluation indicated that the effective dose and X-ray tube load were greater with high-concentration barium sulfate than with moderate-concentration barium sulfate (p < 0.05). The results of the clinical evaluation indicated that the fluoroscopic DAP was greater with moderate-concentration barium sulfate than with high-concentration barium sulfate (p < 0.05), but the radiographic DAP was quite the reverse, so the total DAP and effective dose were almost same with both concentrations of barium sulfate. We conclude that high-concentration barium sulfate does not increase radiation dose in mass screening for gastric cancer. PMID:19623859

Yamamoto, K; Azuma, M; Kuroda, C; Kubo, T; Yabunaka, K; Yamazaki, H; Katsuda, T; Takeda, Y

2009-06-01

14

Sorption of strontium-90 from fresh waters during sulfate modification of barium manganite  

Microsoft Academic Search

Recovery of strontium-90 with barium manganite from fresh waters (natural fresh waters of open basins) can be increased by adding agents that contain sulfate ions and thus modify the sorbent and chemically bind the sorbate. The treatment results in a heterogeneous anion-exchange transformation of barium manganite into barium sulfate-manganese dioxide and in simultaneous absorptive coprecipitation of strontium sulfate (microcomponent).

Yu. V. Egorov

1995-01-01

15

Sorption of strontium-90 from fresh waters during sulfate modification of barium manganite  

SciTech Connect

Recovery of strontium-90 with barium manganite from fresh waters (natural fresh waters of open basins) can be increased by adding agents that contain sulfate ions and thus modify the sorbent and chemically bind the sorbate. The treatment results in a heterogeneous anion-exchange transformation of barium manganite into barium sulfate-manganese dioxide and in simultaneous absorptive coprecipitation of strontium sulfate (microcomponent).

Ryzhen`kov, A.P.; Egorov, Yu.V. [Ural State Technical Univ., Ekaterinburg (Russian Federation)

1995-11-01

16

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.

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

2012-01-01

17

Precipitation of calcium, magnesium, strontium and barium in tissues of four Acacia species (Leguminosae: Mimosoideae).  

PubMed

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

2012-07-25

18

Role of Polyelectrolytes in Barium Sulphate Precipitation.  

National Technical Information Service (NTIS)

In the last decades, the use of additives in precipitation processes to improve process efficiency as well as product performance became more and more common practice. Additives alter the surface properties of the crystals which leads to changes in nuclea...

M. C. van der Leeden

1991-01-01

19

Nickel hydroxide precipitation from aqueous sulfate media  

NASA Astrophysics Data System (ADS)

Hydrometallurgical processing of laterite ores constitutes a major industrial and R&D activity in extractive metallurgy. In some of the process flowsheets, nickel hydroxide precipitation is incorporated. For these operations, the optimization of nickel hydroxide precipitation is important to assure efficiency and product quality. The main objective of this investigation was to study and improve the precipitation characteristics of Ni(OH)2 in a sulfate system using supersaturation controlled precipitation.

Sist, Cinziana; Demopoulos, George P.

2003-08-01

20

The Performance of Barium Sulfate Nanoparticles/polypropylene Hybrid Multifilament  

NASA Astrophysics Data System (ADS)

Nanosize barium sulfate (BaSO4) particles prepared with dodecyl benzene sulfonic acid (DBSA) in ethanol-water reaction system are used to prepare BaSO4/polypropylene (PP) nanocomposites by melt mixing method. It is then made into hybrid fibers by melt spinning and subsequent drawing with different ratios. The hybrid fibers are characterized by rheology, morphology, thermal stability and mechanical properties, respectively. The results indicate that the DBSA-modified BaSO4 can improve the spinnability of BaSO4/PP hybrid multifilament even at high BaSO4 nanoparticles concentration. DBSA can be used as compatibilizer to enhance the interface interaction of BaSO4/PP nanocomposites, because DBSA contains both hydrophobicity long alkyl chain and hydrophilic sulfonic group. Therefore, it can improve the performances of BaSO4/PP hybrid multifilament.

Li, Ying; Wang, Xuanjun; Mu, Xiaoxi; Zhang, Shujuan

2012-12-01

21

High Dispersion Barium Sulfate Nanoparticles Prepared with Dodecyl Benzene Sulfonic Acid  

NASA Astrophysics Data System (ADS)

Production of nanoparticles by precipitation is a relatively simple process but the control of product particle size distribution is difficult. In this paper, nanosize barium sulfate (BaSO4) particles are prepared with dodecyl benzene sulfonic acid (DBSA) in ethanol-water reaction system at room temperature. The BaSO4 nanoparticles are characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), powder X-ray diffraction (XRD), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FT-IR) and thermo gravimetric analysis (TGA), respectively. The results indicated that the average diameter of spherical BaSO4 is about 46 nm modified with 5 wt.% DBSA, which have good dispersion in the presence of a certain concentration NH3 ? H2O. It suggests that the high dispersion is attributed to presence of a thin layer of barium alkyl sulfate, which is formed and coated onto the surface of BaSO4 particles during the reaction process. The thin films on the surface of the BaSO4 effectively modified the surface and properties, which also control the particle size and morphology.

Li, Ying; Wang, Xuanjun; Cui, Yibin; Ma, Wenxin; Guo, Heng

2012-12-01

22

Characterization of dielectric barium titanate powders prepared by homogeneous precipitation chemical reaction for embedded capacitor applications  

Microsoft Academic Search

Various articles have reported that a highly pure and uniform form of barium titanate can be prepared by homogeneous precipitation. However, most of these works emphasize the mechanism of thermal decomposition of barium titanyl oxalate tetrahydrate, and only a few have discussed morphology or particle size. The morphology and particles size of barium titanyl oxalate tetrahydrate are governed by reaction

Jyh-Ming Hwu; Wen-Huai Yu; Wei-Chun Yang; Yu-Wen Chen; Yeh-Yu Chou

2005-01-01

23

CoPrecipitation of Radium and Barium Salts as a Function of Temperature and Acidity  

Microsoft Academic Search

Co-precipitation of radium and barium salts which accompanies the cooling of a solution results in the deposition of a percentage of radium largely in excess of that of barium. Under similar conditions of cooling the relative amounts of radium and barium deposited have been determined at different temperatures throughout the cooling process and curves have been plotted. Determinations of the

W. B. Pietenpol

1942-01-01

24

Comparison of the reflectance characteristics of polytetrafluoroethylene and barium sulfate paints  

NASA Astrophysics Data System (ADS)

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

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

1984-04-01

25

Nanofunctionalized zirconia and barium sulfate particles as bone cement additives  

PubMed Central

Zirconia (ZrO2) and barium sulfate (BaSO4) particles were introduced into a methyl methacrylate monomer (MMA) solution with polymethyl methacrylate (PMMA) beads during polymerization to develop the following novel bone cements: bone cements with unfunctionalized ZrO2 micron particles, bone cements with unfunctionalized ZrO2 nanoparticles, bone cements with ZrO2 nanoparticles functionalized with 3-(trimethoxysilyl)propyl methacrylate (TMS), bone cements with unfunctionalized BaSO4 micron particles, bone cements with unfunctionalized BaSO4 nanoparticles, and bone cements with BaSO4 nanoparticles functionalized with TMS. Results demonstrated that in vitro osteoblast (bone-forming cell) densities were greater on bone cements containing BaSO4 ceramic particles after four hours compared to control unmodified bone cements. Osteoblast densities were also greater on bone cements containing all of the ceramic particles after 24 hours compared to unmodified bone cements, particularly those bone cements containing nanofunctionalized ceramic particles. Bone cements containing ceramic particles demonstrated significantly altered mechanical properties; specifically, under tensile loading, plain bone cements and bone cements containing unfunctionalized ceramic particles exhibited brittle failure modes whereas bone cements containing nanofunctionalized ceramic particles exhibited plastic failure modes. Finally, all bone cements containing ceramic particles possessed greater radio-opacity than unmodified bone cements. In summary, the results of this study demonstrated a positive impact on the properties of traditional bone cements for orthopedic applications with the addition of unfunctionalized and TMS functionalized ceramic nanoparticles.

Gillani, Riaz; Ercan, Batur; Qiao, Alex; Webster, Thomas J

2010-01-01

26

Source Assessment: Major Barium Chemicals.  

National Technical Information Service (NTIS)

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 eff...

H. D. Troy R. B. Rezink

1978-01-01

27

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,...

28

Electron microscope investigation of the thermal aging of barium sulphate precipitates.  

PubMed

Barium sulphate precipitates, formed by four different analytical methods, dried and ignited at different temperatures, have been examined with an electron microscope. The study of the dissolution of precipitates has been found useful for the investigation of thermal aging. On heating the precipitates, diffusion, which takes place at temperatures depending on structure, permits structural changes such as reordering to take place. Consequently, the structure of the ignited precipitates approaches the ideal arrangement. PMID:18959931

Buzágh-Gere, E; Paulik, F; Erdey, L

1966-05-01

29

Jet-pump crystallizers in reaction-crystallization processes with solid reagent–barium sulphate precipitation study  

Microsoft Academic Search

The research results concerning barium sulphate precipitation from the concentrated water solutions of barium chloride by means of crystalline ammonium sulphate addition are presented. The experiments were carried out in a continuous laboratory DTM crystallizer with inner circulation of suspension. A liquid jet-pump device generating ascending\\/descending flow of medium in a mixing chamber was used. Influences of barium chloride concentration

K. Piotrowski; J. Koralewska; A. Matynia

2010-01-01

30

MDCT appearance of the appendix: how does the low-density barium sulfate oral contrast agent affect it?  

Microsoft Academic Search

We compared the effect of low-density barium sulfate neutral oral contrast agent on the diameter of normal appendix and its\\u000a luminal content versus that of water on multidetector-row CT. CT scans of 24 patients who had been imaged on two separate\\u000a occasions for the evaluation of pancreatic pathology, once with water and subsequently with low-density barium sulfate as\\u000a the neutral

Vahid Yaghmai; Anahita Aghaei-Lasboo; Warren M. Brandwein; Sandra Tochetto; John N. Mafi; Frank H. Miller; Paul Nikolaidis

2011-01-01

31

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

32

Ethanol-sensing characteristics of barium stannate prepared by chemical precipitation  

Microsoft Academic Search

Perovskite-type oxide BaSnO3 has been prepared at reduced temperature. The cubic BaSnO3 phase forms at 400°C when a precipitation method is applied. Thermal analysis indicates that the decomposition temperature of BaSn(OH)6 is below 600°C. The trace amounts of BaCO3 in the precipitate are due to the reaction of barium ions with the atmospheric CO2 in a strong basic solution. Conductance

Shanwen Tao; Feng Gao; Xingqin Liu; Ole Toft Sørensen

2000-01-01

33

Acid precipitation and sulfate deposition in Florida  

SciTech Connect

The acidity of rainfall in Florida has increased markedly in the past 25 years, and the average sulfate and nitrate concentrations have increased by factors of 1.6 and 4.5, respectively, over the period. Annual average pH values below 4.7 now occur over the northern three quarters of the state. Summer rainfall has average pH values 0.2 to 0.3 unit lower than winter rainfall, and sulfate concentrations at most sites are higher in summer. The annual deposition of H+ (about 300 to 500 equivalents per hectare) in northern Florida is a third to a half of the deposition in the heavily impacted northeastern United States; comparable figures for excess sulfate (derived from sulfur dioxide) are 7 to 11 kilograms of sulfur per hectare or 50 to 90 percent of the sulfate deposition rates at Hubbard Brook, New Hampshire.

Brezonik, P.L.; Edgerton, E.S.; Hendry, C.D.

1980-05-30

34

Concentration of Rift Valley Fever and Chikungunya Viruses by Precipitation with Ammonium Sulfate and Potassium Aluminum Sulfate.  

National Technical Information Service (NTIS)

A simple and efficient method for concentrating Rift Valley fever and chikungunya viruses is described. Ammonium sulfate and potassium aluminum sulfate are used as precipitating agents, and the precipitate is resuspended to volumes suitable for further pr...

F. Klein B. G. Mahlandt R. R. Cockey R. Lincoln

1970-01-01

35

Sulfate-Reducing Bacteria Release Barium and Radium from Naturally Occurring Radioactive Material in Oil-Field Barite  

Microsoft Academic Search

Scale and sludge deposits formed during oil production can contain elevated levels of Ra, often coprecipitated with barium sulfate (barite). The potential for sulfate-reducing bacteria to release Ra and Ba (a Ra analog) from oil-field barite was evaluated. The concentration of dissolved Ba increased when samples containing pipe scale, tank sludge, or oil-field brine pond sediment were incubated with sulfate-reducing

2001-01-01

36

Improvement of the magnetic properties of barium hexaferrite nanopowders using modified co-precipitation method  

NASA Astrophysics Data System (ADS)

Barium hexaferrite BaFe12O19 powders have been synthesized using the modified co-precipitation method. Modification was performed via the ultrasonication of the precipitated precursors at room temperature for 1 h and the additions of the 2% KNO3, surface active agents and oxalic acid. The results revealed that single phase magnetic barium hexaferrite was formed at a low annealing temperature of 800 °C for 2 h with the Fe3+/Ba2+ molar ratio 8. The microstructure of the powders appeared as a homogeneous hexagonal platelet-like structure using 2% KNO3 as the crystal modifier. A saturation magnetization (60.4 emu/g) was achieved for the BaFe12O19 phase formed at 1000 °C for 2 h with Fe3+/Ba2+ molar ratio 8 using 5 M NaOH solution at pH 10 in the presence of 2% KNO3. Moreover, the saturation magnetization was 52.2 emu/g for the precipitated precursor at Fe3+/Ba2+ molar ratio 12 in was achieved for the precipitated precursor ultrasonicated for 1 h and then annealed at 1200 °C for 2 h. Coercivities from 956.9 to 4558 Oe were obtained at different synthesis conditions.

Rashad, M. M.; Ibrahim, I. A.

2011-08-01

37

Novel Sulfated Glucomannan-Barium-Alginate Microcapsules in Islet Transplantation: Significantly Decreased the Secretion of Monocyte Chemotactic Protein 1 and Improved the Activity of Islet in Rats  

Microsoft Academic Search

The sulfated glucomannan can be used to filter the heparin-binding properties of cytokines. In this study, novel sulfated glucomannan-barium-alginate (SGA) microcapsules were prepared to encapsulate islets with barium-alginate (ABa) and calcium alginate-poly-l-lysine (APA) microcapsules as controls. SD rat islets were purified as donor cells to Lewis rats that had been treated with streptozotocin. Intraperitoneal transplantation was performed with about 3000

X. Chen; L. Zhang; Z. Qi; B. Guo; L. Zhong; B. Shen; Z. Yan; J. Zhang

2009-01-01

38

Chromium determination in pharmaceutical grade barium sulfate by solid sampling electrothermal atomic absorption spectrometry with Zeeman-effect background correction  

Microsoft Academic Search

A procedure for chromium (Cr) determination in pharmaceutical grade barium sulfate by direct solid sampling electrothermal atomic absorption spectrometry (DSS-ET AAS) with Zeeman-effect background correction was developed. Operational conditions for the proposed procedure and the use of citric acid, ammonium phosphate, palladium and magnesium nitrate as chemical modifiers were evaluated. Pyrolysis and atomization temperatures were set at 1500 and 2400°C,

Rodrigo Cordeiro Bolzan; Luis Frederico Rodrigues; Júlio Cezar Paz de Mattos; Valderi Luiz Dressler; Érico Marlon de Moraes Flores

2007-01-01

39

Comparison of Gastrografin to barium sulfate as a gastrointestinal contrast agent in red-eared slider turtles (Trachemys scripta elegans).  

PubMed

Red-eared slider turtles (Trachemys scripta elegans) commonly develop intestinal obstruction. The gastrointestinal transit time in turtles tends to be longer than in other animals, making a rapid diagnosis of obstruction difficult. Fifteen red-eared sliders were given either Gastrografin or 30% w/v barium sulfate orally to compare ease of administration, transit time, and image quality. Each contrast medium was easy to administer but barium sulfate had to be administered more slowly (mean = 40s) than Gastrografin (mean = 20s) to prevent regurgitation. The mean transit and emptying time of Gastrografin was at least 9 h faster than barium sulfate at all time points except gastric transit. Both contrast media had a smooth, uniform appearance that outlined the mucosa with well-defined margins within the stomach and proximal small intestine. Dilution of Gastrografin occurred as it progressed through the intestines, resulting in decreased opacity in the distal small intestine and colon. Pre-administration packed cell volume and total serum protein levels of four turtles receiving Gastrografin were compared with levels at 24-, 96-, and 168-hours postadministration as well as to four control turtles not receiving contrast medium. Packed cell volume and total serum protein levels did not significantly differ among the Gastrografin and control group. From a clinical perspective, administration of Gastrografin allows for quicker results with only minor hematologic changes in red-eared sliders, but visualization of this contrast medium in the lower gastrointestinal tract may be insufficient for an accurate diagnosis. PMID:20166392

Long, Charles Tyler; Page, Richard B; Howard, Antwain M; McKeon, Gabriel P; Felt, Stephen A

40

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

41

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

42

Preparation and Characterization of Barium Sulfate Particles as Contrast Materials for Surgery  

NASA Astrophysics Data System (ADS)

Barium sulfate particles were prepared from BaCl2 and Na2SO4 under various conditions to explore their potential application as contrast material in endovascular surgery. Ethanol was added for the stabilization of the suspension obtained. Particle characteristics of the samples were determined by SEM and light scattering, while the stability of the suspensions was characterized by sedimentation experiments. Particle characteristics were shown to depend very much on reaction conditions. Particles were obtained in spherical and plate like shape and in a variety of sizes. Primary particles of nanometer size formed aggregates in most cases. Some of the samples had bimodal particle size distribution. Particle characteristics determined from SEM micrographs, by laser light scattering measurements and calculated from sedimentation experiments often differed from each other. The discrepancy could be explained by the dissimilar behavior of various fractions and the different sensitivity of the measurements to them. Some of the samples showed aging phenomena in DMSO leading either to the formation of larger particles or to the break down of aggregates.

Figyelmesi, Árpád; Pukánszky, Béla, Jr.; Bagdi, Kristóf; Tóvölgyi, Zsuzsa; Varga, József; Botz, Lajos; Hudak, Stephan; Dóczi, Tamás; Pukánszky, Béla

43

The Effects of Iron and Thorium Ions on the Kinetics of Precipitation of BaSO4.  

National Technical Information Service (NTIS)

The Coulter Counter has been used to record in situ growth and aging curves for the precipitation of barium sulfate. Teflon was found to catalyze the nucleation of barium sulfate, and iron and thorium were found to alter the mechanism of precipitation by ...

C. E. Bricker D. J. Myers

1969-01-01

44

A thermodynamic investigation of barium and calcium sulfate stability in sediments at an oceanic ridge axis (Juan de Fuca, ODP legs 139 and 169)  

NASA Astrophysics Data System (ADS)

We have used a new thermodynamic model of barium and calcium sulfate solubilities in multicomponent electrolyte solutions (Monnin, 1999) to investigate the stabilities of barite and anhydrite in seawater or in marine sediment porewaters at high temperature and pressure. As a further test supplementing those previously carried out during model development, we have calculated the temperature at which standard seawater becomes saturated with respect to anhydrite. The model predicts that, upon heating at 500 bars, standard seawater becomes saturated with respect to anhydrite at 147 ± 5°C, which compares well with the literature value of 150°C (Bishoff and Seyfried, 1978). At 20 bars the calculated saturation temperature is 117 ± 3°C. This points to a non negligible pressure effect even at moderate pressures. We have calculated the barite and anhydrite saturation indices for the in situ temperatures and pressures, from the composition of porewaters collected at ODP Sites 855, 856, 857, 858, 1035 and 1036 during ODP Legs 139 and 169 (Juan de Fuca and Gorda ridges, NE Pacific). Calculated saturation indices for porewater samples collected at depths corresponding to temperatures between 70° and 110-120°C at an in situ pressure of about 260 bars yield equilibrium values for anhydrite and barite. Saturation indices of samples collected at depths where the temperature exceeds 110-120°C, however, yield values indicating supersaturation with respect to anhydrite and undersaturation with respect to barite. This result is consistent with the redissolution of anhydrite during cooling, leading to the well documented sampling artifact affecting porewater compositions in high temperature marine sediments: anhydrite dissolution increases the porewater sulfate content, which in turn induces a loss of barium from solution through barite precipitation (the common ion effect). We postulate that this redissolution occurs in sediment samples for which the in situ temperature exceeds 110-120°C: below this limit anhydrite remains at equilibrium or does not have time to significantly dissolve before porewaters are sampled.

Monnin, Christophe; Balleur, Sabine; Goffe, Bruno

2003-08-01

45

Formation of shaped barium sulfate-dye hybrids: waste dye utilization for eco-friendly treatment of wastewater  

Microsoft Academic Search

Purpose  Owing to the present complexity and difficulty of concentrated dye wastewater treatment, this work aimed to synthesize a reproducible\\u000a waste-sorbing material for the treatment of wastewater by forming the dye-conjugating complex hybrid.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  The inorganic\\/organic hybridization was applied to prepare the objective material by immobilizing waster dye-Mordant blue\\u000a 9 (MB) with barium sulfate (BaSO4). The composition and pattern of the formed

Hong-Wen Gao; Jing Lin; Wei-Ying Li; Zhang-Jun Hu; Ya-Lei Zhang

2010-01-01

46

Histological and radiographic evaluation of polymethylmethacrylate with two different concentrations of barium sulfate in a sheep vertebroplasty model.  

PubMed

Percutaneous vertebral augmentation with PMMA has been widely performed and usually provides good pain relief and stabilization of fractured vertebrae. Adequate visualization of PMMA during injection is desirable to minimize cement extravasation, so contrast agents such as barium sulfate are commonly added to the PMMA. The aim of this study was to evaluate the differences of histology and radiographic visualization when different concentrations of barium sulfate are mixed with PMMA. Six sheep were utilized in this study. Three vertebrae of each animal were exposed via retroperitoneal approach, and a cavity was created and then filled with either 10% or 30% BaSO4/PMMA, or left empty. Vertebrae were harvested and analyzed radiographically and histologically 12 and 90 days after surgery. Average CT value of the 30% BaSO4/PMMA group was 2.4-fold higher than that of the 10% BaSO4/PMMA group. Foreign-body giant cells were recognized around BaSO4particles at 90 days in the 30% BaSO4 group, whereas few particles were recognized in the 10% group at 90 days, or in either group at 12 days. A very mild giant-cell reaction is induced by a higher concentration of BaSO4 in PMMA, but the marked improvement in cement visualization by increased BaSO4 may be important to minimize more serious complications of cement extravasation during PMMA injection. PMID:16037940

Kobayashi, Naomi; Togawa, Daisuke; Fujishiro, Takaaki; Powell, Kimberly A; Turner, A Simon; Seim, Howard B; Bauer, Thomas W

2005-10-01

47

Alkaline precipitation and aging of Cu(II) in the presence of sulfate  

Microsoft Academic Search

The effect of several operating parameters (reagents concentration, molar ratio, mixing protocol) on the composition and aging of the precipitates obtained by mixing cupric sulfate solutions with NaOH solutions was studied. The precipitate was characterized with chemical analysis (SO4\\/Cu molar ratio), scanning electron microscopy, and X-ray diffraction. pH, free cupric ion activity, and sulfate concentration were measured in the soluble

D. Marani; J. W. Patterson; P. R. Anderson

1995-01-01

48

Spectroscopic study on the precipitation of sodium alkyl sulfate with cetylpyridinium chloride.  

PubMed

The precipitation of sodium alkyl sulfate with cetylpyridinium chloride was obtained under optimized conditions. The conditions for the most efficient formation of precipitates were obtained as longer alkyl chain length of alkyl sulfate (C(14)), higher pH (pH 12), 1.5 M NaCl, and equimolar ratio between anionic and cationic surfactants. The structures and physical properties of surfactant precipitates were investigated with SEM, UV-vis, and FT-IR spectroscopy and light scattering. The precipitate of sodium alkyl sulfate with cetylpyridinium chloride was studied with the pressure-area isotherm at the air/water interface. In addition, the surface morphology of the Langmuir-Blodgett film of surfactant precipitate was observed with atomic force microscopy. PMID:17603067

Song, Hwan Young; Oh, Sun Wha; Moon, Sung Doo; Kang, Young Soo

2007-07-02

49

Barium borosilicate glass a potential matrix for immobilization of sulfate bearing high-level radioactive liquid waste  

NASA Astrophysics Data System (ADS)

Borosilicate glass formulations adopted worldwide for immobilization of high-level radioactive liquid waste (HLW) is not suitable for sulphate bearing HLW, because of its low solubility in such glass. A suitable glass matrix based on barium borosilicate has been developed for immobilization of sulphate bearing HLW. Various compositions based on different glass formulations were made to examine compatibility with waste oxide with around 10 wt% sulfate content. The vitrified waste product obtained from barium borosilicate glass matrix was extensively evaluated for its characteristic properties like homogeneity, chemical durability, glass transition temperature, thermal conductivity, impact strength, etc. using appropriate techniques. Process parameters like melt viscosity and pour temperature were also determined. It is found that SB-44 glass composition (SiO2: 30.5 wt%, B2O3: 20.0 wt%, Na2O: 9.5 wt% and BaO: 19.0 wt%) can be safely loaded with 21 wt% waste oxide without any phase separation. The other product qualities of SB-44 waste glass are also found to be on a par with internationally adopted waste glass matrices. This formulation has been successfully implemented in plant scale.

Kaushik, C. P.; Mishra, R. K.; Sengupta, P.; Kumar, Amar; Das, D.; Kale, G. B.; Raj, Kanwar

2006-11-01

50

Barium appendicitis 1 month after a barium meal.  

PubMed

Abstract Because barium sulfate (BaSO(4)) is not harmful to the mucosa, it is widely used for gastrointestinal imaging. Barium appendicitis is a very rare complication of barium meals and barium enema. We report a case of acute appendicitis associated with retained appendiceal barium. A 47-year-old man presented with right lower abdominal pain after upper gastrointestinal imaging was performed using barium 1 month earlier. The abdominal plain roentgenogram showed an area of retained barium in the right lower quadrant. Multiplanar reconstruction of computed tomography scans showed barium retention in the appendix. Emergency appendectomy was performed. A cross section of the specimen revealed the barium mass. Barium-associated appendicitis is a very rare clinical entity but we should be cautious of this uncommon disease when we encounter barium deposits in the appendix after barium examination. This report is significant because barium was identified both macroscopically and microscopically. PMID:23294068

Urade, Masaaki; Shinbo, Toshihumi

51

Barium Appendicitis 1 Month After a Barium Meal  

PubMed Central

Because barium sulfate (BaSO4) is not harmful to the mucosa, it is widely used for gastrointestinal imaging. Barium appendicitis is a very rare complication of barium meals and barium enema. We report a case of acute appendicitis associated with retained appendiceal barium. A 47-year-old man presented with right lower abdominal pain after upper gastrointestinal imaging was performed using barium 1 month earlier. The abdominal plain roentgenogram showed an area of retained barium in the right lower quadrant. Multiplanar reconstruction of computed tomography scans showed barium retention in the appendix. Emergency appendectomy was performed. A cross section of the specimen revealed the barium mass. Barium-associated appendicitis is a very rare clinical entity but we should be cautious of this uncommon disease when we encounter barium deposits in the appendix after barium examination. This report is significant because barium was identified both macroscopically and microscopically.

Urade, Masaaki; Shinbo, Toshihumi

2012-01-01

52

Behavior of radium and barium in a system including uranium mine waste waters and adjacent surface waters  

Microsoft Academic Search

The effect of a large-scale purification of uranium mine wastewaters, using ion exchange resins or precipitation of barium sulfate, on the concentration of dissolved and suspended forms of radium and barium was studied. Results indicate a variable efficiency of purification, mainly due to uneven operation of ion exchange equipment. The main factors regulating radionuclide forms and concentrations in adjacent surface

Ferdinand. Sebesta; Petr. Benes; Josef. Sedlacek; Jan. John; Roman. Sandrik

1981-01-01

53

Performance of a non-phosphorus antiscalant on inhibition of calcium-sulfate precipitation.  

PubMed

The aim of this study is to report on the performance of a novel non-phosphorus antiscalant, acrylic acid (AA)-allylpolyethoxy carboxylate (APEC), being developed for calcium-sulfate scale inhibition in industrial water systems. The performance of AA-APEC on calcium-sulfate scale inhibition was compared with that of the two commercial inhibitors, polyamino polyether methylene phosphonates (PAPEMP) and polyacrylic acid (PAA), containing the same polyethylene glycol segments or carboxyl functional groups as AA-APEC. The study indicated that AA-APEC could act as a highly effective calcium sulfate inhibitor, having strong ability to inhibit the precipitation of calcium sulfate at a dosage of 2 mg L(-1), showing approximately 83.6% inhibition. The results also showed that AA-APEC dosage, the solution pH, inhibiting temperature, concentration of Ca(2+), and SO(4)(2-) all play important roles in inhibiting calcium-sulfate precipitation. The precipitation thermodynamics and kinetics at different temperatures were also discussed. X-ray diffractometer (XRD) and scanning electron microscope (SEM) analysis showed that AA-APEC strongly affected the texture and the morphology of the deposited calcium sulfate. Calcium sulfate has been inhibited through stabilization by adsorption onto crystal growth sites of nascent crystals altering their morphology. PMID:22678218

Xue, Xiaoxu; Fu, Change; Li, Na; Zheng, Fangfang; Yang, Weiben; Yang, Xiaodi

2012-01-01

54

Preparation of immunoglobulin Y from egg yolk using ammonium sulfate precipitation and ion exchange chromatography.  

PubMed

The objective of this study was to develop an economical, simple, and large-scale separation method for IgY from egg yolk. Egg yolk diluted with 9 volumes of cold water was centrifuged after adjusting the pH to 5.0. The supernatant was added with 0.01% charcoal or 0.01% carrageenan and centrifuged at 2,800 x g for 30 min. The supernatant was filtered through a Whatman no. 1 filter paper and then the filtrate was concentrated to 20% original volume using ultrafiltration. The concentrated solution was further purified using either cation exchange chromatography or ammonium sulfate precipitation. For the cation exchange chromatography method, the concentrated sample was loaded onto a column equilibrated with 20 mM citrate-phosphate buffer at pH 4.8 and eluted with 200 mM citrate-phosphate buffer at pH 6.4. For the ammonium sulfate precipitation method, the concentrated sample was twice precipitated with 40% ammonium sulfate solution at pH 9.0. The yield and purity of IgY were determined by ELISA and electrophoresis. The yield of IgY from the cation exchange chromatography method was 30 to 40%, whereas that of the ammonium sulfate precipitation was 70 to 80%. The purity of IgY from the ammonium sulfate method was higher than that of the cation exchange chromatography. The cation exchange chromatography could handle only a small amount of samples, whereas the ammonium sulfate precipitation could handle a large volume of samples. This suggests that ammonium sulfate precipitation was a more efficient and useful purification method than cation exchange chromatography for the large-scale preparation of IgY from egg yolk. PMID:17234857

Ko, K Y; Ahn, D U

2007-02-01

55

Role of temperature in the spontaneous precipitation of calcium sulfate dihydrate  

SciTech Connect

The spontaneous precipitation of calcium sulfate in supersaturated solutions over the temperature range between 25.0 and 80.0 C was investigated by monitoring the solution specific conductivity during desupersaturation. From measurements of the induction times preceding the onset of precipitation the surface energy of the forming solid, identified as gypsum, was found between ca. 12 and 25 mJ/m{sup 2} for the temperature range between 80.0 and 25.0 C, respectively. Kinetics analysis showed that over 50 C it is possible that anhydrous calcium sulfate is forming as a transient phase converting into the more stable calcium sulfate dihydrate. The linear dependence of the rates of precipitation on the relative solution supersaturation suggested a mechanism according to which the growth units are integrated into the active sites of the supercritical nuclei by surface diffusion. According to the morphological examination of the crystals it is possible that crystal growth occurs by the advancement of steps.

Klepetsanis, P.G.; Dalas, E.; Koutsoukos, P.G. [Univ. of Patras (Greece)

1999-02-16

56

Features of ferric sulfate precipitates formed by different cultivations of Acidithiobacillus ferrooxidans  

Microsoft Academic Search

This study focused on the ferric sulfate precipitates formed during the culture of Acidithiobacillus ferrooxidans (A. ferrooxidans) in a modified 9K medium by applying a potential control on the electrode. X-ray diffraction (XRD), environmental scanning\\u000a electron microscope (ESEM), Raman spectroscopy (Raman) and Fourier Transform Infrared spectroscopy (FTIR) were carried out\\u000a to characterize and identify the precipitates which were formed, respectively,

Xin Wang; Anhuai Lu; Changqiu Wang

2010-01-01

57

PROCESS USING POTASSIUM LANTHANUM SULFATE FOR FORMING A CARRIER PRECIPITATE FOR PLUTONIUM VALUES  

DOEpatents

A process is presented for recovering plutonium values in an oxidation state not greater than +4 from fluoride-soluble fission products. The process consists of adding to an aqueous acidic solution of such plutonium values a crystalline potassium lanthanum sulfate precipitate which carries the plutonium values from the solution.

Angerman, A.A.

1958-10-21

58

A comparison of the dodecyl sulfate-induced precipitation of the myelin basic protein with other water-soluble proteins  

Microsoft Academic Search

The interactions of sodium dodecyl sulfate with a number of proteins were examined at a variety of pH values ranging from 4.8 to 11.6 The dodecyl sulfate-induced precipitation of some of these proteins was observed within a relatively limited range of total dodecyl sulfate concentration. Most of the basic proteins precipitated at low pH but as the isoelectric point of

John E. Moskaitis; Anthony T. Campagnoni

1986-01-01

59

Sulfate reduction and copper precipitation by a Citrobacter sp. isolated from a mining area.  

PubMed

A strain of sulfate-reducing bacteria, designated strain 'DBM', was isolated from sediments of a mining area. Phylogenetic analysis of the 16S rRNA gene sequence of the isolate revealed that it was related to members of the genus Citrobacter, with C. AzoR-4, C. freundii, C. braakii and C. werkmanii being the most closely related species (sequence similarity up to 98%). Few studies have been done on sulfate reduction ability in Citrobacter. Electron microscopy studies showed that the morphology of the strain DBM was rod-shaped. Strain DBM reduced 10mM of sulfate completely to sulfide within 7d, and it recovered its sulfate reduction ability after 7d of aerobic growth. Furthermore, strain DBM effectively precipitated 0.40 mM copper during its growth. Elemental composition of the resulting microbial precipitate was studied using electro-dispersive X-ray spectroscopy, and it was found that the ratio of S:Cu was 1.07. The result was consistent with the formation of copper sulfide. Heavy metal precipitation by Citrobacter sp. strain DBM was a phenomenon that may be useful in the bioremediation of acid mine drainage. PMID:18977087

Qiu, Rongliang; Zhao, Benliang; Liu, Jinling; Huang, Xiongfei; Li, Qingfei; Brewer, Eric; Wang, Shizhong; Shi, Ning

2008-09-19

60

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

Microsoft Academic Search

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,

Anne-Laure Sandré; Alain Gaunand

61

Short-Range Dissolution-Precipitation Crystallization of Hydrothermal Barium Titanate  

SciTech Connect

A modified autoclave was used to investigate the crystallization mechanism of BaTiO3 during the hydrothermal reaction of Ba(OH)2 and TiO2 anatase. An uneven distribution of the crystallized BaTiO3 particles was observed: more than 99 wt% of total BaTiO3 articles remained where the precursor TiO2 was put; less than 1 wt% was collected from the areas away from the TiO2. According to the experimental observations in this work and proofs reported in the literature, we propose that the crystallization mechanism is dissolution-precipitation in nature, but the soluble Ti4+ species can only redisperse in a short distance away from TiO2 particles before precipitation. In another words, the nucleation of hydrothermal BaTiO3 starts at a low concentration of Ti4+. The mechanism of the Ba(OH)2-Ti(OH)4 reaction is a fast dehydration process.

Qi, Lai; Lee, Burtrand I.; Badheka, Prerak; Yoon, Dang-Hyok; Samuels, William D.; Exarhos, Gregory J.

2004-07-01

62

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...

63

Linked Redox Precipitation of Sulfur and Selenium under Anaerobic Conditions by Sulfate-Reducing Bacterial Biofilms  

PubMed Central

A biofilm-forming strain of sulfate-reducing bacteria (SRB), isolated from a naturally occurring mixed biofilm and identified by 16S rDNA analysis as a strain of Desulfomicrobium norvegicum, rapidly removed 200 ?M selenite from solution during growth on lactate and sulfate. Elemental selenium and elemental sulfur were precipitated outside SRB cells. Precipitation occurred by an abiotic reaction with bacterially generated sulfide. This appears to be a generalized ability among SRB, arising from dissimilatory sulfide biogenesis, and can take place under low redox conditions and in the dark. The reaction represents a new means for the deposition of elemental sulfur by SRB under such conditions. A combination of transmission electron microscopy, environmental scanning electron microscopy, and cryostage field emission scanning electron microscopy were used to reveal the hydrated nature of SRB biofilms and to investigate the location of deposited sulfur-selenium in relation to biofilm elements. When pregrown SRB biofilms were exposed to a selenite-containing medium, nanometer-sized selenium-sulfur granules were precipitated within the biofilm matrix. Selenite was therefore shown to pass through the biofilm matrix before reacting with bacterially generated sulfide. This constitutes an efficient method for the removal of toxic concentrations of selenite from solution. Implications for environmental cycling and the fate of sulfur and selenium are discussed, and a general model for the potential action of SRB in selenium transformations is presented.

Hockin, Simon L.; Gadd, Geoffrey M.

2003-01-01

64

Barium borosilicate glass – a potential matrix for immobilization of sulfate bearing high-level radioactive liquid waste  

Microsoft Academic Search

Borosilicate glass formulations adopted worldwide for immobilization of high-level radioactive liquid waste (HLW) is not suitable for sulphate bearing HLW, because of its low solubility in such glass. A suitable glass matrix based on barium borosilicate has been developed for immobilization of sulphate bearing HLW. Various compositions based on different glass formulations were made to examine compatibility with waste oxide

C. P. Kaushik; R. K. Mishra; P. Sengupta; Amar Kumar; D. Das; G. B. Kale; Kanwar Raj

2006-01-01

65

A method for evaluation of acidic sulfate and nitrate in precipitation  

Microsoft Academic Search

A simple method is presented and used to estimate the portions of SOinf4sup2-and NOinf-sup3that contribute to the strong acidity in weekly precipitation samples collected at three NADP sites in the eastern United States. The method assumes that, in general, the difference between SOinf4sup2-and NHinf+sup4represents acidic sulfate and the difference between NOinf-sup3and soil-derived materials (the sum of Ca2+, Mg2+, and K+)

D. L. Sisterson

1989-01-01

66

Treatment of spent brine from a nitrate exchange process using combined biological denitrification and sulfate precipitation.  

PubMed

A combined biological denitrification and sulfate precipitation process was developed to treat and reuse the spent brine produced by a nitrate exchange system. Although the spent brine contained a relatively high salt concentration, more than 80% of NO3(-)-N fed into the denitrification reactors was removed at a nitrate-N loading rate of 2.2 g NO3(-)-N/l x day, regardless of the presence or absence of sulfate up to 8,000 mg/l. Sulfate present in the spent brine was successfully removed by the addition of BaCl2 and the settling velocity of BaSO4 suspension was remarkably enhanced by FeCl3 coagulation. Since most of the chloride consumed in regenerating the exhausted resins was replaced during chemical treatment with BaCl2 and FeCl3, it was possible to reuse the treated spent brine as a regenerant after compensating for the small amount of unreplaced NaCl. PMID:15137452

Bae, B U; Kim, C H; Kim, Y I

2004-01-01

67

Three-dimensional current flow and particle precipitation in a westward travelling surge (observed during the barium-GEOS rocket experiment)  

SciTech Connect

During the Barium-GEOS rocket experiment on September 24, 1979 the passage of a westward travelling surge (WTS) was observed over Scandinavia. Extended instrument networks in that area, viz., the Scandinavian Magnetometer Array, the STARE radars, all-sky cameras, and riometers, allowed simultaneous observation of the two-dimensional character of magnetic and electric field disturbances and particle precipitation associated with the auroral feature. By combination of the different datasets and additional information from particle and electric field measurements aboard the Barium-GEOS rocket it was possible to derive the two-dimensional distribution of ionospheric electric fields and conductivities and to model the three-dimensional current flow in the vicinity of the westward travelling surge. The main feature of the resulting model current system is the presence of a localized upward field-aligned current directed out of the head of the surge and fed by a westward electrojet, which is composed of both Hall and Pedersen currents. Secondary ionospheric currents, e.g. a counterclockwise loop of mainly Hall currents around the leading edge of the surge, are found to be responsible for most of the transient effects observed by ground-based magnetometers as the WTS passed overhead. The most energetic particle precipitation as inferred from cosmic noise absorption measurements and triangulation of auroral arc altitudes is found to be confined to the leading part and central regions of the surge and to travel westward with the visual auroral form.

Opgenoorth, H.J.; Pellinen, R.J.; Baumjohann, W.; Nielsen, E.; Marklund, G.; Eliasson, L.

1983-04-01

68

Synthesis and analyses of thermal decomposition and microstructure of Sr-doped barium titanate alkoxide derived precipitates and thin films  

Microsoft Academic Search

The structure and thermal decomposition process of Ba0.8Sr0.2TiO3 (BST) powders and thin films, which were prepared from a precursor of Sr-doped barium titanate alkoxides, were investigated by means of differential thermal\\/thermogravimetric analyses (DTA\\/TGA), X-ray diffractometer (XRD), AFM, and Fourier transform infrared spectroscopy (FTIR) measurements. From the FTIR spectra, it has been possible to observe that gel powders pyrolyzed and crystallized

Hu-Yong Tian; Wei-Gen Luo; Xing-Hua Pu; Ping-Sun Qiu; Xi-Yun He; Ai-li Ding

2000-01-01

69

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

70

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

71

Effect of unintentionally extruded calcium hydroxide paste including barium sulfate as a radiopaquing agent in treatment of teeth with periapical lesions: report of a case.  

PubMed

Calcium hydroxide [Ca(OH)2] has been widely used as short- or long-term intracanal antibacterial dressing material after endodontic treatment. In general when used in endodontics, Ca(OH)2 paste is composed of the powder, a vehicle, and a radiopacifier. To provide radiopacity, barium sulfate (BaSO4) powder is usually added to the paste. In this case report, BaSO4:Ca(OH)2 powders (ratio 1:8) and distilled water were mixed and applied as dressing material after root canals of mandibular left canine and premolar teeth with periapical lesions. However, the prepared paste was unintentionally extruded into the periapical lesion during application. The patient was seen 12 and 36 months later, at which point periapical healing was evaluated. At this time, it was observed that the periapical lesion had disappeared, but white radiopaque spots were seen at the place where calcium hydroxide remnants had originally been present. The presented case report reveals that when Ca(OH)2 paste that included BaSO4 was applied as an intracanal dressing and extruded through the periapical lesion associated with pulpless teeth, it had no detrimental effect. However, healing might take longer when Ca(OH)2 paste including BaSO4 is used, so deliberate overextension is not advocated. PMID:18571001

Orucoglu, Hasan; Cobankara, Funda Kont

2008-05-22

72

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

PubMed

Monitoring the degradation of calcium phosphate-based bone substitute materials in vivo by means of noninvasive techniques (e.g., radiography) is often a problem due to the chemical resemblance of those substitutes with the mineral phase of bone. In the view of that, the present study aimed at enhancing the radiopacity of calcium phosphate cement enriched with poly(lactic-co-glycolic acid) (CPC-PLGA) microspheres, by adding tantalum oxide (Ta2 O5 ) or the more traditional radiopacifier barium sulfate (BaSO4 ). The radiopacifying capacity of these radiopacifiers was first evaluated in vitro by microcomputed tomography (?CT). Thereafter, both radiopacifiers were tested in vivo using a distal femoral condyle model in rabbits, with subsequent ex vivo ?CT analysis in parallel with histomorphometry. Addition of either one of the radiopacifiers proved to enhance radiopacity of CPC-PLGA in vitro. The in vivo experiment showed that both radiopacifiers did not induce alterations in biological performance compared to plain CPC-PLGA, hence both radiopacifiers can be considered safe and biocompatible. The histomorphometrical assessment of cement degradation and bone formation showed similar values for the three experimental groups. Interestingly, ?CT analysis showed that monitoring cement degradation becomes feasible upon incorporation of either type of radiopacifier, albeit that BaSO4 showed more accuracy compared to Ta2 O5 . © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013. PMID:23613219

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

2013-04-24

73

Assessment of sulfate sources in high-elevation Asian precipitation using stable sulfur isotopes.  

PubMed

Stable sulfur isotope measurements (delta34S) made on samples collected from a 2 m snowpit on the Inilchek Glacier, Tien Shan Mountains (42.16 degrees N, 80.25 degrees E, 5100 m) are used to estimate sources of sulfate (SO4(2-)) in high-elevation Central Asian precipitation. Comparison of snowpit oxygen isotope (delta18O) data with previous work constrains the age of the snowpit samples to the summer season during which they were retrieved (1999). Delta34S measurements were made at 10 cm resolution (20 samples total), with delta34S values ranging from 0.4/1000 during background ([SO4(2-)] < 1 microequiv L(-1)) periods to 19.4/1000 during a single high [SO4(2-)] event. On the basis of the significant correlation (r = 0.87) between [SO4(2-)] and delta34S values, coupled with major ion concentration time series and concentration ratios, we suggest a two-component mixing system consisting of evaporite dust and anthropogenic SO4(2-) to explain the observed delta34S values. Using a regression model, we estimate that during the 1999 summer season 60% of the deposited SO4(2-) was from an evaporite dust source, while 40% of the SO4(2-) was from anthropogenic sources. Due to the potentially large and unconstrained range of delta34S values for both evaporite and anthropogenic SO4(2-) sources in Asia, the error in our estimates is difficult to assess. However, the delta34S data from the 1999 Tien Shan snowpit provide the first unambiguous identification of evaporite and anthropogenic SO4(2-) in high-elevation Asian precipitation, and future ice core studies using improved analysis techniques and source delta34S values can provide detailed information on sulfur biogeochemistry and anthropogenic impacts in Asian alpine regions. PMID:15487779

Pruett, Lee E; Kreutz, Karl J; Wadleigh, Moire; Aizen, Vladimir

2004-09-15

74

Evidence for Aqueously Precipitated Sulfates in Northeast Meridiani Using Themis and Tes Data.  

National Technical Information Service (NTIS)

Recently aqueously deposited sulfate- rich bedrock was found at the MER-B Meridiani landing site. Additional sulfate was observed from orbit by the Mars Express OMEGA instrument. In this work, I present midinfrared spectral evidence (using THEMIS and TES)...

M. D. Lane

2005-01-01

75

The role of non-precipitating clouds in producing ambient sulfate during summer: Results from simulations with the Acid Deposition and Oxidant Model (ADOM)  

NASA Astrophysics Data System (ADS)

A comprehensive acid deposition model was used to investigate the importance of non-precipitating stratus clouds for the production of ambient sulfate. A comparison of model estimates of ambient sulfate and SO 2 concentrations with corresponding observations for an episode in the summer of 1988 showed that the model underestimated ambient sulfate concentrations and overestimated ambient SO 2 concentrations when non-precipitating stratus clouds were ignored in the model formulation. When the model was modified to include non-precipitating stratus clouds, a distinct improvement in model performance was obtained.

Karamchandani, Prakash; Venkatram, Akula

76

Determination of HDL 2 cholesterol by precipitation with dextran sulfate and magnesium chloride: Establishing optimal conditions for rat plasma  

Microsoft Academic Search

Optimal conditions for analyzing HDL2 cholesterol in small amounts of rat plasma have been studied using different concentrations of dextran sulfate and MgCl2 to precipitate lipoproteins containing apolipoprotein B and\\/or apo E. When the MgCl2 level was 91 mM, the supernate cholesterol was rather constant at a level of about 50–60% of the total plasma cholesterol\\u000a concentration. Immunochemical determination of

Linnea Sjoblom; Anders Eklund

1989-01-01

77

Precipitation of monodispersed basic iron(III) sulfate (sodium jarosite) particles  

Microsoft Academic Search

Uniform sodium jarosite particles were obtained by forced hydrolysis of ferric salt solutions to which copper sulfate, sodium\\u000a sulfate, and sodium nitrate were added. It was found that at the same concentrations of ferric and sulfate ions the particle\\u000a size and yield decreased with the lowering of the concentration of sodium ions, but the morphology remained the same. At a

I. Sondi; S. Shi; E. Matijevic´

2001-01-01

78

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

2012-03-11

79

Influence of sodium dodecyl sulfate and static magnetic field on the properties of freshly precipitated calcium carbonate.  

PubMed

Properties of calcium carbonate precipitated from aqueous solutions of CaCl(2) and Na(2)CO(3) in the presence of sodium dodecyl sulfate (SDS) and S-S 0.1 T magnetic field (MF) were studied. The nucleation and precipitation processes of CaCO(3) were investigated by pH and zeta potential measurements at 20 +/- 1 degrees C up to 2 h after mixing the solutions. Also the amounts of calcium carbonate deposited on the glass surfaces and its structure were examined. It was found that SDS influences the kinetics of precipitation, crystallographic forms, and crystal size of CaCO(3). The SDS effects are more pronounced in MF presence. A small amount of SDS accelerates transformation of vaterite into calcite, whereas increasing surfactant concentration moderates such a transformation. On the other hand, in all the systems, MF in the presence of SDS causes a slower transformation of vaterite into calcite. These effects are reflected in pH and zeta potential changes, although there is no clear dependence between the SDS amount present during the precipitation and changes of the parameters investigated. It seems that MF effect is most significant at a defined optimal SDS concentration. The results, however, do not allow suggestion of any detailed mechanism of the field interaction. PMID:16114911

Chibowski, Emil; Szczes, Aleksandra; Holysz, Lucyna

2005-08-30

80

ACID PRECIPITATION: EFFECTS OF SULFUR DIOXIDE AND SULFATE AEROSOL PARTICLES ON HUMAN HEALTH  

EPA Science Inventory

While human health impairment has been attributed to pollution by sulfur dioxide (SO2), data from inhalation studies in animals show that its oxidation products are more irritating. Population surveys in which suspended sulfate was a co-variant suggest that certain health paramet...

81

Intramural extravasation of barium simulating carcinoma of the rectum  

Microsoft Academic Search

This report describes two patients found to have barium granuloma of the rectum. The lesions appeared as indurated, ulcerated\\u000a rectal masses that resembled carcinoma on endoscopic examination. Deep mucosal biopsy results demonstrated no malignancy and\\u000a barium sulfate crystals in tissue macrophages. Radiographs showed persistent soft-tissue barium in the rectum. Past reports\\u000a of barium granuloma have described ulcerated or polypoid masses

John E. Phelps; Robert A. Sanowski; Richard A. Kozarek

1981-01-01

82

Recovery of copper sulfate after treating As-containing wastewater by precipitation method  

Microsoft Academic Search

The solid sodium hydroxide neutralized acidic As-containing wastewater till pH value was 6. Green copper arsenite was prepared\\u000a after copper sulfate was added into the neutralized wastewater when the molar ratio of Cu to As was 2:1 and pH value of the\\u000a neutralized wastewater was adjusted to 8.0 by sodium hydroxide. The arsenious acid solution and red residue were produced

Ya-jie Zheng; Yong Wang; Fa-xin Xiao; Yuan Luo

2009-01-01

83

The crystal chemistry of a naturally occurring magnesium hydroxide sulfate hydrate, a precipitate of heated seawater  

Microsoft Academic Search

The crystal chemistry of a naturally occurring magnesium hydroxide sulfate hydrate, MgSO 4 · 1\\/3 Mg ( OH 2 ) · 1\\/3 H 2 O (designated MHSH(2\\/3)), and a number of existing and predicted compounds which are structurally related to MHSH(2\\/3) are discussed. An x-ray diffraction powder pattern for MHSH(2\\/3) is calculated from single crystal data to aid in the

Michael F. Hochella Jr.; Keith D. Keefer; Bernard H. W. S. Dejong

1983-01-01

84

Acridine Orange, a precipitant for sulfated glycosaminoglycans, causes mucopolysaccharidosis in cultured fibroblasts  

Microsoft Academic Search

The purpose of the present investigation was to examine whether or not a di-cationic amphiphilic compound that is known (1) to be accumulated in lysosomes and (2) to form insoluble complexes with sulfated glycosaminoglycans (sGAG) in vitro, is able to interfere with the lysosomal degradation of sGAG, thus causing mucopolysaccharidosis (MPS) in cultured cells. Acridine Orange (AO) was chosen for

R. Liillmann-Rauch; M. Ziegenhagen

1991-01-01

85

STABLE SULFUR ISOTOPES OF SULFATE IN PRECIPITATION AND STREAM SOLUTIONS IN A NORTHERN HARDWOODS WATERSHED  

EPA Science Inventory

table 5 isotopes of 5042 in precipitation and stream solutions in a northern hardwoods watershed (Bear Brooks Watershed, Maine) were examined to determine sources of stream S042- and to identify watershed processes that may affect atmospherically deposited S042 prior to reaching ...

86

In vivo rheologic effects of lipid apheresis techniques: comparison of dextran sulfate LDL adsorption and heparin induced LDL precipitation.  

PubMed

The effects of two different LDL apheresis techniques, heparin-induced LDL precipitation (HELP) and dextran sulfate LDL adsorption (DSA), were compared in six patients with familial hypercholesterolemia. Total and LDL cholesterol were effectively lowered with both techniques. The reduction of serum triglycerides was more pronounced with DSA, whereas the reduction of HDL cholesterol was more pronounced with HELP. Single sessions using both techniques immediately reduced whole blood and plasma viscosity, as well as erythrocyte aggregation. Serum fibrinogen decreased by 62% (HELP) and 11% (DSA). Maintenance lipid apheresis administered 1 time per week resulted in a sustained reduction of total and LDL cholesterol and was associated with a sustained improvement in blood flow properties. Data suggest that besides serum fibrinogen, serum lipoproteins may adversely effect the rheologic characteristics of blood. PMID:2252691

Grützmacher, P; Landgraf, H; Esser, R; Okon, J; Vlachojannis, J; Ehrly, A M; Schoeppe, W

87

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

88

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).

89

Expulsion of Barium and Methane at Mud Volcanoes in the Gulf of Mexico  

NASA Astrophysics Data System (ADS)

Submarine mud volcanoes and cold-seeps along continental margins transfer methane from gas-charged marine sediments to the water column. Such methane venting is dynamic and may provide an important and variable supply of carbon to the ocean and atmosphere through time. Barite mounds and chimneys have been found around some modern mud volcanoes and seeps, and similar structures can be identified in the geological record (e.g., bedded barite deposits). These observations suggest that expelled methane-rich fluids are greatly enriched in dissolved barium. However, there are very few analyses of barium concentrations in these systems. Here, we examine the dissolved barium of pore fluids from a series of shallow piston cores across two submarine mud volcanoes in the Gulf of Mexico. Dissolved barium concentrations at 1.5 m below the seafloor at the Garden Bank volcano range from 18200 ? M at the center of the feature to 0.56 ? M on its flanks approximately 1 km away. Similarly, dissolved barium concentrations at the Mississippi Canyon volcano range from 15600 ? M to 0.50 ? M. Thus, the concentrations in the cores of the mud volcanoes are nominally 5 orders of magnitude greater than in mean ocean water ( ˜0.1 ? M). Anaerobic oxidation of upward flowing methane consumes sulfate, which leads to the dissolution of barite and release of barium to pore fluids. Because this mechanism alone cannot explain the extreme concentrations in the mud volcanoes, a deep source of barium may exist in the Gulf of Mexico strata. Our current work is focused on quantifying the fluxes and sedimentary fate of expelled barium at these locations. However, even if a large fraction of the barium precipitates adjacent to the sites of methane venting, fluid expulsion at mud volcanoes must significantly impact the barium cycle in the Gulf of Mexico. Conceivably, submarine mud volcanoes and cold-seeps along continental margins are a major source of barium to the deep ocean, a concept that has profound implications with respect to certain paleoceanographic reconstructions.

Castellini, D. G.; Dickens, G. R.; Snyder, G. T.; Gilhooly, W. P.; Ruppel, C. D.

2003-12-01

90

Selectivity in biomineralization of barium and strontium.  

PubMed

The desmid green alga Closterium moniliferum belongs to a small number of organisms that form barite (BaSO(4)) or celestite (SrSO(4)) biominerals. The ability to sequester Sr in the presence of an excess of Ca is of considerable interest for the remediation of (90)Sr from the environment and nuclear waste. While most cells dynamically regulate the concentration of the second messenger Ca(2+) in the cytosol and various organelles, transport proteins rarely discriminate strongly between Ca, Sr, and Ba. Herein, we investigate how these ions are trafficked in C. moniliferum and how precipitation of (Ba,Sr)SO(4) crystals occurs in the terminal vacuoles. Towards this goal, we simultaneously visualize intracellular dynamics of multiple elements using X-ray fluorescence microscopy (XFM) of cryo-fixed/freeze-dried samples. We correlate the resulting elemental maps with ultrastructural information gleaned from freeze-fracture cryo-SEM of frozen-hydrated cells and use micro X-ray absorption near edge structure (micro-XANES) to determine sulfur speciation. We find that the kinetics of Sr uptake and efflux depend on external Ca concentrations, and Sr, Ba, and Ca show similar intracellular localization. A highly ion-selective cross-membrane transport step is not evident. Based on elevated levels of sulfate detected in the terminal vacuoles, we propose a "sulfate trap" model, where the presence of dissolved barium leads to preferential precipitation of (Ba,Sr)SO(4) due to its low solubility relative to SrSO(4) and CaSO(4). Engineering the sulfate concentration in the vacuole may thus be the most direct way to increase the Sr sequestered per cell, an important consideration in using desmids for phytoremediation of (90)Sr. PMID:21871966

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

2011-08-17

91

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

92

Low-Sulfate Seawater Injection into Oil Reservoir to Avoid Scaling Problem  

NASA Astrophysics Data System (ADS)

This study presents the results of laboratory experiments carried out to investigate the formation of calcium, strontium and barium sulfates from mixing Angsi seawater or low sulfate seawater with the following sulfate contents (75, 50, 25, 5 and 1%) and formation water contain high concentration of calcium, strontium and barium ions at various temperatures (40-90°C) and atmospheric pressure. The knowledge of solubility of common oil field scale formation and how their solubilities are affected by changes in salinity and temperatures is also studied. Results show a large of precipitation occurred in all jars containing seawater while the amount of precipitation decreased when the low sulfate seawater was used. At higher temperatures the mass of precipitation of CaSO4 and SrSO4 scales increases and the mass of precipitation of BaSO4 scale decreases since the solubilities of CaSO4 and SrSO4 scales decreases and the solubility of BaSO4 increases with increasing temperature. It can be concluded that even at sulfate content of 1% there may still be a scaling problem.

Merdhah, Amer Badr Bin; Mohd Yassin, Abu Azam

93

Experimental analysis of arsenic precipitation during microbial sulfate and iron reduction in model aquifer sediment reactors  

NASA Astrophysics Data System (ADS)

Microbial SO 42- reduction limits accumulation of aqueous As in reducing aquifers where the sulfide that is produced forms minerals that sequester As. We examined the potential for As partitioning into As- and Fe-sulfide minerals in anaerobic, semi-continuous flow bioreactors inoculated with 0.5% (g mL -1) fine-grained alluvial aquifer sediment. A fluid residence time of three weeks was maintained over a ca. 300-d incubation period by replacing one-third of the aqueous phase volume of the reactors with fresh medium every seven days. The medium had a composition comparable to natural As-contaminated groundwater with slightly basic pH (7.3) and 7.5 ?M aqueous As(V) and also contained 0.8 mM acetate to stimulate microbial activity. Medium was delivered to a reactor system with and without 10 mmol L -1 synthetic goethite (?-FeOOH). In both reactors, influent As(V) was almost completely reduced to As(III). Pure As-sulfide minerals did not form in the Fe-limited reactor. Realgar (As 4S 4) and As 2S 3(am) were undersaturated throughout the experiment. Orpiment (As 2S 3) was saturated while sulfide content was low (˜50 to 150 ?M), but precipitation was likely limited by slow kinetics. Reaction-path modeling suggests that, even if these minerals had formed, the dissolved As content of the reactor would have remained at hazardous levels. Mackinawite (Fe 1 + xS; x ? 0.07) formed readily in the Fe-bearing reactor and held dissolved sulfide at levels below saturation for orpiment and realgar. The mackinawite sequestered little As (<0.1 wt.%), however, and aqueous As accumulated to levels above the influent concentration as microbial Fe(III) reduction consumed goethite and mobilized adsorbed As. A relatively small amount of pyrite (FeS 2) and greigite (Fe 3S 4) formed in the Fe-bearing reactor when we injected a polysulfide solution (Na 2S 4) to a final concentration of 0.5 mM after 216, 230, 279, and 286 days. The pyrite, and to a lesser extent the greigite, that formed did sequester As from solution, containing 0.84 and 0.23 wt.% As on average, respectively. Our results suggest that As precipitation during Fe-sulfide formation in nature occurs mainly in conjunction with pyrite formation. Our findings imply that the effectiveness of stimulating microbial SO 42- reduction to remediate As contamination may be limited by the rate and extent of pyrite formation and the solubility of As-sulfides.

Kirk, Matthew F.; Roden, Eric E.; Crossey, Laura J.; Brealey, Adrian J.; Spilde, Michael N.

2010-05-01

94

Precipitation in solutions containing mixtures of synthetic anionic surfactant and soap. I. Effect of sodium octanoate on hardness tolerance of sodium dodecyl sulfate  

Microsoft Academic Search

The effect of sodium octanoate (SO) and pH on the precipitation of sodium dodecyl sulfate (SDS) with calcium (hardness tolerance)\\u000a in water was investigated. SO can exist as octanoate anion (O?) or as the protonated nonionic fatty acid (HO) with the HO\\/O? ratio increasing with decreasing pH. At intermediate pH levels, SO or SO\\/SDS systems are composed of mixtures of

Cheryl H. Rodriguez; Chanin Chintanasathien; John F. Scamehorn; Chintana Saiwan; Sumaeth Chavadej

1998-01-01

95

Novel thermally stable poly(vinyl chloride) composites for sulfate removal.  

PubMed

BaCO(3) 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 synthesize barium carbonate-loaded silica aero-gels-polyvinyl chloride (PVC) polymer composites. The PVC composites were characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray mapping, X-ray diffraction (XRD), thermogravimetric analysis (TGA) and inductively coupled plasma mass spectrometry (ICP-MS) analysis. The method has advantages over conventional sulfate precipitation (sulfate removal process) using BaCO(3) wherein clogging of the filter can be avoided. The method is environmentally friendly and does not interfere with natural organic matter as the conventional resin does. Some of the composites were thermally more stable as compared with the pure PVC discussed in the literature. PMID:21277679

Nadagouda, Mallikarjuna N; Pressman, Jonathan; White, Colin; Speth, Thomas F; McCurry, Daniel L

2011-01-12

96

Acidity, valency and third-ion effects on the precipitation of scorodite from mixed sulfate solutions under atmospheric-pressure conditions  

NASA Astrophysics Data System (ADS)

The present study is focused on the precipitation of scorodite from mixed sulfate media at 95 °C under atmospheric pressure. In particular, this study explores the effects of acidity (pH), valency [Fe(II)/Fe(III), As(III)/As(V)], and solution composition (third cation/anion) on the yield, crystallinity, and stability (leachability) of scorodite precipitates. Thus, it was found that the precipitation of crystalline scorodite can be achieved without stringent pH control once the precipitation has started. Nonetheless, the selection of the initial pH is critical to avoid the formation of an amorphous precipitate. A leachability as low as 0.5 mg/L As at pH 5 and 22 °C (TCLP-like test) is obtained when the initial molar ratio Fe(III):As(V) is increased to 3:1, but the precipitation yield is very low. When Fe(II) is used as excess iron, the precipitate solubility drops to 0.2 mg/L As with a yield exceeding 80 pct in 2.5 hours. The stability of the product is not measurably affected by the presence of Cu2+, Zn2+, Ni2+, Co2+, Mn2+, SO{4/2-}, and NO{3/-}. The presence of PO{4/3-}, however, leads to the formation of crystalline phosphate-containing scorodite precipitates of somewhat reduced stability. In most cases, the TCLP leachability of the precipitate was found to be between 1 and 3 mg/L As, and never exceeded the regulatory limit of 5 mg/L As.

Singhania, Shalabh; Wang, Qiankun; Filippou, Dimitrios; Demopoulos, George P.

2006-04-01

97

Microemulsion-assisted precipitation of particles: Experimental and model-based process analysis  

Microsoft Academic Search

The technical-scale production of nanoparticles with tailored properties is of particular interest due to the increasing demand from industry. This study provides the basis for the scale-up of the synthesis route in water-in-oil (w\\/o)-microemulsion droplets by a detailed experimental and theoretical analysis of the precipitation of calcium carbonate (CaCO3) and barium sulfate (BaSO4). The used w\\/o-microemulsion system consists of water,

B. Niemann; F. Rauscher; D. Adityawarman; A. Voigt; K. Sundmacher

2006-01-01

98

Microbial dolomite precipitation using sulfate reducing and halophilic bacteria: Results from Qinghai Lake, Tibetan Plateau, NW China  

Microsoft Academic Search

Past studies have revealed the important roles of certain types of microbes in precipitating dolomite in coastal hypersaline lakes and lagoons, and marine sediments, however, it is still poorly known if other types of microbes can precipitate dolomite in low-salinity lakes without any marine influence. The objective of this study was therefore to expand the microbial dolomite precipitation model by

Shicai Deng; Hailiang Dong; Guo Lv; Hongchen Jiang; Bingsong Yu; Michael E. Bishop

2010-01-01

99

The dynamics of calcium phosphate precipitation studied with a new polyacrylamide steady state matrix-model: influence of pyrophosphate collagen and chondroitin sulfate.  

PubMed

A novel steady-state gel-matrix model system is described which facilitates the quantitative kinetic study of the influence of media and matrix composition on a precipitation process. The potentialities of the system are illustrated in experiments in which the precipitation of calcium phosphate in a polyacrylamide film is studied as a function of the calcium and phosphate concentration in the solutions flowing along opposite sides of the film. Addition of pyrophosphate to the reactant solutions was found to diminish the (calcium) x (phosphate) millimolar product at which precipitation starts, indicating a positive effect on nucleation. The slope of the curve was found to decrease, which points to a negative influence of pyrophosphate on the crystal growth process. Incorporation of collagen in the matrix did not change the curve, but incorporation of chondroitin sulfate decreased the formation product since the intercept of the curve was reduced. The usefulness of the system compared with test-tube and non-steady state gel experiments for calcium phosphate precipitation studies and its significance for the study of in vitro and in vivo precipitation processes in general, are discussed. PMID:6244132

de Jong, A S; Hak, T J; van Duijn, P

1980-01-01

100

Factors influencing the recovery of dopamine sulfate in the assay of phenol sulfotransferase  

SciTech Connect

Phenol sulfotransferase activity is often measured by incubating dopamine with a source of the enzyme and the sulfate donor /sup 35/S-3'-phosphoadensine-5'-phosphosulfate and then separating the product, /sup 35/S-dopamine sulfate, from the substrates using precipitation with barium hydroxide and zinc sulfate. Using dopamine sulfate standards and high performance liquid chromatography with dual-electrode electrochemical detection, the authors investigated the effects of several parameters on product recovery obtained with this procedure. Amounts of precipitants needed to produce maximal sample-to-blank ratios were determined using crude enzyme preparations from rat brain and human platelets incubated under conditions generating approximately 3 nM dopamine sulfate. Under these conditions, recovery of /sup 3/H-DAS standards was 70-80%. Increasing either the concentration of dopamine sulfate or the amounts of precipitants used resulted in concentration-dependent decreases in dopamine sulfate recovery. These data indicate that the recovery of product in this assay may vary with assay conditions, and should be carefully monitored and optimized. Caution should be exercised when using substrates other than dopamine in this assay procedure, since similar factors might also contribute to variable recovery of other produces. 14 references, 4 figures, 2 tables.

Toth, L.A.; Kao, G.; Elchisak, M.A.

1987-02-02

101

Temperature and seeding effects on the precipitation of scorodite from sulfate solutions under atmospheric-pressure conditions  

Microsoft Academic Search

Arsenic is a major contaminant in the nonferrous extractive metallurgy. In the past 20 years, many studies have shown that\\u000a it can be precipitated as relatively stable crystalline scorodite (FeAsO42H2O) by precipitation under ambient or elevated pressures. In the present study, an extensive program of scorodite precipitation\\u000a tests under ambient pressure has shown that the rate of scorodite formation increases

Shalabh Singhania; Qiankun Wang; Dimitrios Filippou; George P. Demopoulos

2005-01-01

102

Thermal decomposition of (BaTi) citrates into barium titanate  

Microsoft Academic Search

From aqueous solutions of barium and titanium citrates two different (BaTi) citrate salts can be precipitated, depending on the pH of the solution. The ratio of barium to titanium in the salts is either 1 : 1 or 2 : 1. The thermal decomposition of the salts was investigated by means of DTA, TGA, infrared spectroscopy, and X-ray diffraction. At

D. Hennings; W. Mayr

1978-01-01

103

Barium enema (image)  

MedlinePLUS

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

104

Radar and satellite studies of the impact of mesoscale convective precipitation and wind systems on visibility, sulfates, and oxidants during persistent elevated pollution episodes  

SciTech Connect

The results are consistent and supportive, but certainly not conclusive, of a hypothesis suggesting that PBL sulfate mass removal into the free troposphere are on the order of several times that deposited on the surface during convective rainfalls. Thus, given the highly episodic nature of wet deposition and the potential major contribution of a single event to a season's total, a need exists to better understand the contributions of the various MCPS types to visibility improvement and sulfate removal, both to the surface and especially into the free atmosphere. Few projects are cited in the literature in which the precipitation chemistry data were even crudely stratified into major storm types though Raynor and Hayes did find significantly higher surface deposition during frontal thunderstorms and squall lines. Hales and Dana suggest the importance of designing an experiment to achieve an accurate closure of species mass balance within the entire domain of a convective storm. In noting the extreme variability in species washout over a region, they speculate that the bulk of the variability within and between storms must occur by superposition of the effects of inhomogeneous storm features, as well as source characteristics. Grant stated that a definitive characterization of individual storm dynamics and trajectories must be performed before long-term trends can be established with certainty. From the viewpoint of a severe storms meteorologist, much of the effort ongoing to understand regional wet deposition, sulfate, ozone, and visibility patterns, is subject to large errors of interpretation unless an attempt is made to better understand the highly different ways in which various precipitation systems, convective and stratiform, impact the PBL.

Lyons, W.A.; Calby, R.H.

1983-06-01

105

Rapid synthesis of submicron crystalline barium zirconate BaZrO 3 by precipitation in aqueous basic solution below 100 °C  

Microsoft Academic Search

Pure crystalline BaZrO3 powders can be produced by precipitation in highly basic aqueous solution. The influence of several synthesis parameters is studied. At high OH? concentration ([NaOH]=20mol\\/l), it is possible to obtain the well-crystallized stoichiometric perovskite phase at relatively low temperature (?80°C), after a short reaction time (15min) and without requiring any precaution to avoid the presence of CO2. This

Frédéric Boschini; André Rulmont; Rudi Cloots; Bénédicte Vertruyen

2009-01-01

106

Ultrafine Barium Titanate Powders via Microemulsion Processing Routes  

Microsoft Academic Search

Three processing routes have been used to prepare barium titanate powders, namely conventional coprecipitation, single-microemulsion coprecipitation using diether oxalate as the precipitant, and double-microemulsion coprecipita- tion using oxalic acid as the precipitant. A single-phase perovskite barium titanate was obtained when the double- microemulsion-derived oxalate precursor was calcined for 2 h at a temperature of as low as 550°C, compared to

John Wang; Jiye Fang; Ser-Choon Ng; Leong-Ming Gan; Chwee-Har Chew; Xianbin Wang; Zexiang Shen

2004-01-01

107

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

108

Barium Granuloma of the Rectum: An Uncommon Complication of Barium Enema  

PubMed Central

Barium sulfate granuloma of the rectum may develop when this contrast material is forced through a discontinuity in the rectal mucosa. The ensuing mass may be confused with carcinoma. Preoperative biopsy and attention to plain films will prevent unnecessary inappropriate surgery. ImagesFig. 1.Fig. 2.Fig. 3a.Fig. 3b.

Lewis, Joseph W.; Kerstein, Morris D.; Koss, Neal

1975-01-01

109

HDL cholesterol quantitation by phosphotungstate-Mg2+ and by dextran sulfate-Mn2+-polyethylene glycol precipitation, both with enzymic cholesterol assay compared with the lipid research method.  

PubMed

Two methods using commercial kits for high density lipoprotein (HDL) cholesterol quantitation were compared with the Lipid Research Clinics (LRC) procedures. HDL cholesterol quantitations on 50 patient specimens by the Lancer HDL cholesterol Rapid Stat Kit (Lancer) with phosphotungstate-Mg2+ precipitation and enzymic cholesterol assay averaged 424 mg/L, and by a method with dextran sulfate-Mn2+-polyethylene glycol (dextran sulfate) precipitation and enzymic cholesterol assay averaged 474 mg/L. By comparison, the LRC method (heparin-Mn2+ precipitation combined with a Liebermann-Burchard reagent cholesterol assay) averaged 478 mg/L. Supernates obtained by the three precipitation methods had similar cholesterol values when analyzed by the LRC assay, suggesting that the observed differences were primarily due to differences between the cholesterol assays. Results were consistent with underestimation by the enzymic assay of cholesterol in the supernates, offset by a positive interference of Mn2+ in the dextran sulfate-produced supernates. Among-day CVs of 4-5% were observed for the Lancer method, and 6-7% for the dextran sulfate method. Sedimentation of precipitates in hypertriglyceridemic specimens was excellent by both methods. PMID:6182791

Warnick, G R; Mayfield, C; Benderson, J; Chen, J S; Albers, J J

1982-11-01

110

Akaganéite (?-FeOOH) precipitation in inland acid sulfate soils of south-western New South Wales (NSW), Australia  

NASA Astrophysics Data System (ADS)

The prevalence of sulphidic sediments in inland wetlands has been only recently recognized in many parts of the world, including Australia. The exposure of sulphidic sediments in these wetlands due to natural and human induced drying events has resulted in the oxidation of iron sulfide minerals, the formation of secondary iron minerals characteristic of acid sulfate soils and the release of highly acidic solutions. The objective of this study was to determine the mineralogy and morphology of sediments collected from the oxidized surface horizon (0-5 cm) of an inland acid sulfate soil located in south-western New South Wales (NSW), Australia. Random powder X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning transmission electron microscopy combined with energy dispersive X-ray spectroscopy (STEM-EDS) techniques were used to characterize the minerals present in these sediments. Akaganéite was identified as the major mineral phase in the sediments; K-jarosite was also determined in small amounts in some sediments. The XRD patterns of sequentially washed (E-pure® water-0.01 M HCl-0.01 M EDTA) sediment samples showed all akaganéite peaks; the Rietveld refinement of these patterns also revealed a predominance of akaganéite. The chemical analyses of the original and washed sediments using STEM-EDS clearly showed the presence of akaganéite as a pure mineral phase with an average Fe/Cl mole ratio of 6.7 and a structural formula of Fe 8O 8(OH) 6.8(Cl) 1.2. These findings show that the extreme saline-acidic solutions (pH ˜ 2, EC = 216 dS/m) at the Bottle Bend lagoon provide ideal conditions for the crystallization of this rarely forming mineral.

Bibi, Irshad; Singh, Balwant; Silvester, Ewen

2011-11-01

111

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

112

Drinking Water Criteria Document for Sulfate.  

National Technical Information Service (NTIS)

Sulfate is a common divalent anion found in a number of minerals in the environment. Sulfate salts of sodium ion, potassium ion, or magnesium ion are soluble in water, whereas salts of calcium ion, barium ion and other heavy metals are poorly soluble or i...

1990-01-01

113

Barium and Radium Radiopolarography.  

National Technical Information Service (NTIS)

Radiopolarography has been applied to the study of two elements (barium and radium) which is difficult by classical polarography because of their strong electropositivity. Various parameters have been considered: nature, concentration and pH of supporting...

B. Fourest

1979-01-01

114

Column experiments to assess the effects of electron donors on the efficiency of in situ precipitation of Zn, Cd, Co and Ni in contaminated groundwater applying the biological sulfate removal technology  

Microsoft Academic Search

Background, Aims and Scope  In a previous study, we explored the use of acetate, lactate, molasses, Hydrogen Release Compound (HRC®, which is based on\\u000a a biodegradable poly-lactate ester), methanol and ethanol as carbon source and electron donor to promote bacterial sulfate\\u000a reduction in batch experiments, this with regards to applying an in situ metal precipitation (ISMP) process as a remediation tool

Joke Geets; Karolien Vanbroekhoven; Brigitte Borremans; Jaco Vangronsveld; Ludo Diels; Daniel van der Lelie

2006-01-01

115

Lower GI Series (Barium Enema)  

MedlinePLUS

... because the large intestine is filled with barium liquid. The barium liquid coats the lining of the large intestine and ... bowel prep instructions. Generally, patients follow a clear liquid diet for 1 to 3 days before the ...

116

X-ray diffraction studies on aluminum-substituted barium hexaferrite  

Microsoft Academic Search

Effect of aluminum substitution in barium hexaferrite was studied following the hydrothermal precipitation–calcination techniques. It was attempted to prepare aluminum-substituted barium hexaferrites with compositions BaAlxFe12?xO19 having x=2,4, 6, 8 and 10. The precursors were prepared by using stoichiometric amounts of Ba, Al and Fe3+ nitrate solutions with urea as the precipitating agent. The hydrothermally prepared precursors were calcined at temperatures

D. Mishra; S. Anand; R. K. Panda; R. P. Das

2004-01-01

117

Chondroitin sulfate  

MedlinePLUS

... contain chondroitin sulfate, in combination with glucosamine sulfate, shark cartilage, and camphor. But as far as we ... containing chondroitin sulfate in combination with glucosamine sulfate, shark cartilage, and camphor seems to reduce arthritis symptoms. ...

118

Glucosamine sulfate  

MedlinePLUS

... Glucosamine Potassium Sulfate, Glucosamine Sulfate 2KCl, Glucosamine Sulfate-Potassium Chloride, Glucosamine Sulphate, Glucosamine Sulphate KCl, Glucosamine-6-Phosphate, GS, Mono-Sulfated Saccharide, Poly-(1->3)-N- ...

119

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

120

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

121

Sulfate, nitrate declines noted  

NASA Astrophysics Data System (ADS)

An analysis of more than 4000 samples of precipitation that were collected weekly from 1978 through 1983 at 19 sites in 13 states showed no clear pattern of changes in overall acidity, according to a recent report by the U.S. Geological Survey (USGS) of the Department of the Interior. The analysis did, however, reveal significant declines in sulfate and nitrate concentrations during that 5-year period.USGS hydrologists said that sulfate and nitrate, sometimes used as indirect indicators of the acidity of precipitation, showed widespread and substantial downward trends in the eastern United States. (All but three of the 19 stations are located east of the Mississippi River.) At the five stations in Ohio, Pennsylvania, and West Virginia, for example, sulfate concentrations declined 25% to 40% during the 5-year period. Only two of those five stations showed statistically significant trends in pH; these were decreases in acidity comparable to the decreases in sulfate.

122

Necrotizing proctitis caused by injection of barium into the wall of the rectum  

Microsoft Academic Search

Conclusion  It is the authors’ belief that when the barium enema was administered inflation forced the tip of the Bardex catheter into\\u000a the rectal mucosa. Rand8 believes that inflation causes high intraluminal pressure by preventing the escape of contrast media through the anus.\\u000a \\u000a Apparently, this is the first reported case in which accidental introduction of barium sulfate suspension into the wall

John A. Altobelli; TAKEO YAMASI-HTA; Guy L. Kratzer

1970-01-01

123

Rapid barium removal in the Delaware estuary  

SciTech Connect

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

Stecher, H.A. III [Univ. of Delaware, Lewes, DE (United States). College of Marine Studies]|[Univ. of Delaware, Newark, DE (United States). Dept. of Geology; Kogut, M.B. [Univ. of Washington, Seattle, WA (United States). School of Oceanography

1999-04-01

124

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

125

Barium carbonate intoxication  

Microsoft Academic Search

A 22-year-old man attempted to commit suicide by swallowing an unknown amount of barium carbonate dissolved in hydrochloric acid. Shortly after ingestion, he developed crampy abdominal pain and generalized muscle weakness. About 2 h later, respiratory failure ensued necessitating orotracheal intubation and mechanical ventilation. Concomitantly, life-threatening arrhythmias including ventricular fibrillation occurred, and he had to be resuscitated for 45 min.

Th. F. Schorn; Ch. Olbricht; A. Schüler; A. Franz; K. Wittek; H.-J. Balks; E. Hausmann; H.-H. Wellhoener

1991-01-01

126

A Meteorology-Based Approach to Detecting the Relationship between Changes in SO2 Emission Rates and Precipitation Concentrations of Sulfate  

Microsoft Academic Search

In this paper, the authors present an analysis of correlations between SO2 emissions and wet SO24 concentrations over eastern North America that includes adjustments for the impact of meteorological variability. The approach uses multiple-regression models and readily available meteorological information to analyze precipitation chemistry data collected from 1979 to 1986 at six Utility Acid Precipitation Study Program site. On an

Jeffrey R. Brook; Perry J. Samson; Sanford Sillman

1994-01-01

127

Barium Vanadate Microspheres  

NASA Astrophysics Data System (ADS)

It has been found that many glass powders can form micro- or nanospheres when heated in a flame or by a laser. Much of the research in this area of microspheres has concentrated on making hollow spheres, called microballoons, of silica and borosilicate glasses. Our aim was to create highly porous barium vanadate microspheres for possible future applications in material storage. The surface area of porous spheres would provide a greater amount of bonding surface area for dopants than hollow spheres. Barium vanadate glass with a molar fraction of 0.4 to 0.6 barium oxide was used because this glass is stable and has a low Tg. Size distributions of the spheres were quantified and the extent of sphere formation and porosity was examined using a scanning electron microscope. The size of spheres formed is affected by powder size, dropping method, and flame position. The porosity of the microspheres is affected by flame temperature, time spent in flame, and the material onto which the spheres fall. The greatest porosity was achieved by first heating the glass powder at a low temperature and then immediately sending it through the flames of two MAPP gas torches at approximately 2100^oC onto a metal sheet.

Yosinski, Shari; Tweeton, Landon; Feller, Steve; Affatigato, Mario

2009-11-01

128

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

129

75 FR 33824 - Barium Chloride From China  

Federal Register 2010, 2011, 2012, 2013

...731-TA-149 (Third Review)] Barium Chloride From China Determination On the basis...the antidumping duty order on barium chloride from China would be likely to lead to...4157 (June 2010), entitled Barium Chloride from China: Investigation No....

2010-06-15

130

75 FR 19657 - Barium Chloride From China  

Federal Register 2010, 2011, 2012, 2013

...731-TA-149 (Third Review)] Barium Chloride From China AGENCY: United States International...the antidumping duty order on barium chloride from China...the antidumping duty order on barium chloride from China would be likely to lead...

2010-04-15

131

Concentration of Rift Valley Fever and Chikungunya Viruses by Precipitation.  

National Technical Information Service (NTIS)

Simple and efficient methods for concentrating Rift Valley fever (RVF) virus and chikungunya (CHIK) virus are described. Ammonium sulfate, potassium sulfate, or alcohol was used as a precipitating agent and the precipitate was resuspended to volumes suita...

B. G. Manlandt F. Klein R. E. Lincoln R. R. Cockey

1970-01-01

132

Morphine Sulfate  

Center for Drug Evaluation (CDER)

Text Version... Contains Nonbinding Recommendations Draft Guidance on Morphine Sulfate This ... Drugs. Active ingredient: Morphine Sulfate ... More results from www.fda.gov/downloads/drugs/guidancecomplianceregulatoryinformation

133

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

134

Sulfate washout ratios in winter storms  

Microsoft Academic Search

Washout ratios for sulfate were computed from simultaneous measurements of sulfate in precipitation and in the air below cloud base. Stratification of the data according to predominant mode of precipitation growth (growth primarily by accretion of liquid cloud droplets versus growth primarily by vapor deposition onto ice particles) illustrated that for cases of accretional growth, the washout ratio was 10--50

B. C. Scott

1981-01-01

135

Effects of composition and calcination temperature on morphology and structure of barium modified zirconia nanoparticles  

Microsoft Academic Search

Co-precipitation of zirconyl chloride and barium chloride followed by supercritical ethanol drying was used to synthesize the barium modified zirconia nanoparticles. BET surface area, X-ray diffraction (XRD) and atomic force microscopy (AFM) measurements were employed for structural and morphological characterization. Crystallite particles of ?10 to 50nm in size with cross-linking boundaries were formed during heat treatment. Results show that the

Aiguo Liu; Kafui Nyavor; Zhimin Li; Nosa O Egiebor

2004-01-01

136

Discovery of the barium isotopes  

SciTech Connect

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

Shore, A.; Fritsch, A.; Ginepro, J.Q.; Heim, M.; Schuh, A. [National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Thoennessen, M., E-mail: thoennessen@nscl.msu.ed [National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)

2010-11-15

137

Suicidal poisoning with barium chloride.  

PubMed

A 49-year-old male pharmacist suffering from depression phoned the emergency services telling of how he had ingested barium chloride. He was found semicomatose in bed and resuscitation attempts were to no avail and he died at the scene. A white plastic container labelled "Barium chloride... Poison", and a book with a writing on a blank page... "give sulphate... SO(4)" were found. At autopsy, 1l of whitish-yellow fluid was found in the stomach. Autopsy barium levels were: blood 9.9mg/l; bile 8.8mg/l; urine 6.3mg/l; gastric 10.0g/l. Cause of death was given as cardiorespiratory arrest due to barium chloride poisoning. The issue of barium toxicity in a variety of itatrogenic and non itatrogenic situation is discussed together with the two only other cases of suicidal barium ingestion, and the feasibility of early intervention at the scene by an emergency team. PMID:11376995

Jourdan, S; Bertoni, M; Sergio, P; Michele, P; Rossi, M

2001-06-15

138

Monohydroxylation of unsaturated oils: I. Sulfation-hydrolysis and sultone-formation  

Microsoft Academic Search

Hydroxy unsaturated glycerides were sought from safflower and linseed oils by partial sulfation with sulfuric acid, followed\\u000a by hydrolysis of sulfate to hydroxy groups. Sulfation of oleicrich oils or their fatty acids and subsequent hydrolysis (effected\\u000a conveniently with acidified barium chloride) yielded hydroxy products corresponding to 50–70% of the monoene content. Sulfation\\u000a of a mixture of methyl oleate and linoleate

G. Venkateswara Rao; K. T. Achaya

1970-01-01

139

Sources of sulfate supporting anaerobic metabolism in a contaminated aquifer  

USGS Publications Warehouse

Field and laboratory techniques were used to identify the biogeochemical factors affecting sulfate reduction in a shallow, unconsolidated alluvial aquifer contaminated with landfill leachate. Depth profiles of 35S-sulfate reduction rates in aquifer sediments were positively correlated with the concentration of dissolved sulfate. Manipulation of the sulfate concentration in samples revealed a Michaelis-Menten-like relationship with an apparent Km and Vmax of approximately 80 and 0.83 ??M SO4-2??day-1, respectively. The concentration of sulfate in the core of the leachate plume was well below 20 ??M and coincided with very low reduction rates. Thus, the concentration and availability of this anion could limit in situ sulfate-reducing activity. Three sulfate sources were identified, including iron sulfide oxidation, barite dissolution, and advective flux of sulfate. The relative importance of these sources varied with depth in the alluvium. The relatively high concentration of dissolved sulfate at the water table is attributed to the microbial oxidation of iron sulfides in response to fluctuations of the water table. At intermediate depths, barite dissolves in undersaturated pore water containing relatively high concentrations of dissolved barium (???100 ??M) and low concentrations of sulfate. Dissolution is consistent with the surface texture of detrital barite grains in contact with leachate. Laboratory incubations of unamended and barite-amended aquifer slurries supported the field observation of increasing concentrations of barium in solution when sulfate reached low levels. At a deeper highly permeable interval just above the confining bottom layer of the aquifer, sulfate reduction rates were markedly higher than rates at intermediate depths. Sulfate is supplied to this deeper zone by advection of uncontaminated groundwater beneath the landfill. The measured rates of sulfate reduction in the aquifer also correlated with the abundance of accumulated iron sulfide in this zone. This suggests that the current and past distributions of sulfate-reducing activity are similar and that the supply of sulfate has been sustained at these sites.

Ulrich, G. A.; Breit, G. N.; Cozzarelli, I. M.; Suflita, J. M.

2003-01-01

140

Barium Geochemistry of a Marginal Cold-seep Basin: Abundance and Provenance of Total Barium and Barite in the San Clemente Basin.  

NASA Astrophysics Data System (ADS)

Barium in marine sediments is found in various solid phases including barite, aluminosilicates, carbonates, organic material and oxyhydroxides. Barite, the dominant Ba-bearing solid phase in pelagic settings, is of particular interest as it has the potential for use as a tracer for paleoproductivity and past isotopic and rare earth element composition of seawater. Barite crystals form by abiotic precipitation in supersaturated microenvironments of decaying organic material in the water column and then settle as aggregates to the sediments. In areas of cold seep activity, discharge of barium-rich seep fluid also results in large in situ barite deposits at the seafloor. Transport of particles from these deposits leads to significantly increased barium concentrations in surrounding sediments. The San Clemente basin located about 100km off the coast of San Diego, is one such location where massive barite deposits have been observed in association with cold seep activity along the San Clemente fault that transects the basin. Analysis of surface sediments from the San Clemente basin has shown total barium enrichment of up to 140% higher than surface sediments from the neighboring Santa Catalina basin. Cold seeps are not present in the latter location, where the major source of barite is likely to be that associated with biogenic material. The significant input of barium from authigenic barite deposits to surrounding sediments affects global barium geochemistry and could possibly be used to provide a paleorecord for cold seep activity.

McQuay, E. L.; Torres, M. E.; Collier, R.; Huh, C.; Newell, S.

2004-12-01

141

Deflocculants for Tape Casting Barium Titanate.  

National Technical Information Service (NTIS)

The dispersion properties of disperants with barium titanate were studied. Rheological, settling, volume and adsorption isotherms were obtained for barium titanate in MEK-ethanol using a phosphate ester dispersant. Effects of storage conditions, dispersan...

W. R. Cannon

1983-01-01

142

Barium hexaferrite (M-phase) exhibiting superstructure  

Microsoft Academic Search

Barium hexaferrite (M-phase) prepared by the flux method is found to exhibit a ..sqrt..3a x ..sqrt..3a superstructure similar to barium hexaaluminate. Morgan and Shaw as well as Iyi et al have recently reported the formation of a barium-rich phase of barium hexaaluminate possessing a ..sqrt..3a x ..sqrt..3a superstructure of the magnetoplumbite structure. In view of the similarities between the layer

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

1984-01-01

143

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

144

[Speciation and characterization of interaction of PACls with sulfate].  

PubMed

The interaction of sulfate with various PACl was investigated by using Ferron assay, chemical analysis and SEM. The experimental results showed that the basicity (B = [OH]/[Al]) exhibited significant role in the PACl-sulfate reaction. It indicated different species in various PACl under different reaction pathway with sulfate. The Alc formed precipitation quickly with sulfate, while Alb underwent slowly crystalization. The decrease of Ala resulted in the limit of ferron method. The different speciation component in PACls formed different crystal morphology and chemical composition with sulfate. Increase the basicity, the content of sulfate in precipitate decreased from 0.45 to 0.30. PMID:14551960

Jiang, Huaming; Wang, Dongsheng; Wang, Lianjun

2003-07-01

145

Study on the Structure and Mechanical Properties of Dental Barium Glass Particles Surface Modification with Silane Coupling Reagent  

Microsoft Academic Search

The surface-modified dental barium glass with silane coupling reagent KH-570 was studied. The prepared samples before and after modification were characterized by static precipitation, angle of contact, transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared ray, and thermo-gravimetric analysis. Research showed that the KH-570 was bound on the surface of barium glass, a firm chemical bonding of KH-570 to

Xie Chao; Wang Zhong-Yi; He Hui-Ming; Han Ying; Gu Jun-Wei

2008-01-01

146

Computer modelling of barium titanate  

Microsoft Academic Search

Barium titanate is an important material for both scientific and industrial applications. Much of the interest centres around its ferroelectric properties, since it is structurally the most simple in this class. In addition rare-earth doped ceramics are found to exhibit a very steep positive temperature coefficient of resistance (PTCR) above the Curie point. The theory of this PTCR effect is

G. V. Lewis; C. R. A. Catlow

1983-01-01

147

The Vapor Pressure of Barium.  

National Technical Information Service (NTIS)

The vapor pressure and the heat of vaporization of barium were measured using the Knudsen target technique. A recording microbalance was used to measure both the effusion rate and the recoil force exerted by the beam onto the target. The measured vapor pr...

P. D. Zavitsanos

1968-01-01

148

CT-Guided Percutaneous Transthoracic Localization of Pulmonary Nodules Prior to Video-Assisted Thoracoscopic Surgery Using Barium Suspension  

PubMed Central

Objective To describe our initial experience with CT-guided percutaneous barium marking for the localization of small pulmonary nodules prior to video-assisted thoracoscopic surgery (VATS). Materials and Methods From October 2010 to April 2011, 10 consecutive patients (4 men and 6 women; mean age, 60 years) underwent CT-guided percutaneous barium marking for the localization of 10 small pulmonary nodules (mean size, 7.6 mm; range, 3-14 mm): 6 pure ground-glass nodules, 3 part-solid nodules, and 1 solid nodule. A 140% barium sulfate suspension (mean amount, 0.2 mL; range, 0.15-0.25 mL) was injected around the nodules with a 21-gauge needle. The technical details, surgical findings and pathologic features associated with barium localizations were evaluated. Results All nodules were marked within 3 mm (mean distance, 1.1 mm; range, 0-3 mm) from the barium ball (mean diameter, 9.6 mm; range, 8-16 mm) formed by the injected barium suspension. Pneumothorax occurred in two cases, for which one needed aspiration. However, there were no other complications. All barium balls were palpable during VATS and visible on intraoperative fluoroscopy, and were completely resected. Both the whitish barium balls and target nodules were identifiable in the frozen specimens. Pathology revealed one invasive adenocarcinoma, five adenocarcinoma-in-situ, two atypical adenomatous hyperplasias, and two benign lesions. In all cases, there were acute inflammations around the barium balls which did not hamper the histological diagnosis of the nodules. Conclusion CT-guided percutaneous barium marking can be an effective, convenient and safe pre-operative localization procedure prior to VATS, enabling accurate resection and diagnosis of small or faint pulmonary nodules.

Lee, Nyoung Keun; Kang, Chang Hyun; Jeon, Yoon Kyung; Choo, Ji Yung; Lee, Hyun-Ju; Goo, Jin Mo

2012-01-01

149

21 CFR 82.3 - Definitions.  

Code of Federal Regulations, 2013 CFR

...term blanc fixe means a suspension in water of precipitated barium sulfate. (i) The term gloss white means a suspension in water of co-precipitated aluminum hydroxide and barium sulfate. (j) The term mixed oxides means the...

2013-04-01

150

Barium uptake and adsorption in diatoms  

NASA Astrophysics Data System (ADS)

Using trace metal-defined culture conditions, we measured the cellular barium concentration in cultures of the diatom Thalassiosira weissflogii. In cultures with low Fe concentration, at a typical surface seawater Ba concentration of 35 to 40 nmol/L, the cellular Ba was 0.5 ?mol/mol P (˜0.04 ?g/g dw), much below all previously published values for phytoplankton. When the Fe concentration in the growth medium was increased, the measured "cellular" Ba increased proportionally to the particulate Fe. Under conditions of ferric hydroxide precipitation, similar particulate Ba concentrations were measured in the absence and the presence of cells for a given concentration of particulate Fe. Thus, the bulk of the particulate Ba in such experiments was not truly intracellular but adsorbed on precipitated Fe hydroxides associated with the cell surface. A similar mechanism likely explains the high cellular Ba concentrations reported by previous investigators who utilized relatively high ratios of Fe to EDTA concentrations in the growth medium, resulting in Fe precipitation. On the basis of our results, it seems highly unlikely that intracellular uptake by living phytoplankton explains the vertical flux of Ba in oceanic waters. But the adsorption of Ba on Fe hydroxides that is seen in laboratory experiments must also occur in the oceans and contribute to Ba transport in the upper part of the water column. To be significant, however, such a mechanism would require that the particles that transport Ba out of the surface have a markedly lower Ba/Fe ratio than is measured in the average suspended material.

Sternberg, Erika; Tang, Degui; Ho, Tung-Yuan; Jeandel, Catherine; Morel, François M. M.

2005-06-01

151

STUDIES ON ALKALINE-EARTH METAL POLYMETAPHOSPHATES PREPARED BY PRECIPITATION AND DEHYDRATION  

Microsoft Academic Search

Barium, strontium, calcium and magnesium polymetaphosphate hydrate powders were prepared by precipitation from aqueous solution and their dehydrations to amorphous anhydrous powders were studied in detail by a variety of physico-chemical methods. Anhydrous barium and strontium polymetaphosphates were formed through two dehydration processes whereas calcium and magnesium polymetaphosphates were formed through dehydration, hydrolysis (with depolymerisation) and repolymerisation processes, over the

A. Packter; W. O. S. Doherty

1983-01-01

152

Electron donors for biological sulfate reduction.  

PubMed

Biological sulfate reduction is widely used for treating sulfate-containing wastewaters from industries such as mining, tannery, pulp and paper, and textiles. In biological reduction, sulfate is converted to hydrogen sulfide as the end product. The process is, therefore, ideally suited for treating metal-containing wastewater from which heavy metals are simultaneously removed through the formation of metal sulfides. Metal sulfide precipitates are more stable than metal hydroxides that are sensitive to pH change. Theoretically, conversion of 1 mol of sulfate requires 0.67 mol of chemical oxygen demand or electron donors. Sulfate rich wastewaters are usually deficient in electron donors and require external addition of electron donors in order to achieve complete sulfate reduction. This paper reviews various electron donors employed in biological sulfate reduction. Widely used electron donors include hydrogen, methanol, ethanol, acetate, lactate, propionate, butyrate, sugar, and molasses. The selection criteria for suitable electron donors are discussed. PMID:17572039

Liamleam, Warounsak; Annachhatre, Ajit P

2007-05-17

153

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

154

Fate of sulfate during the thermophilic methane fermentation process  

Microsoft Academic Search

The reactor design utilized was the suspended growth thermophilic anaerobic contact system. The experimental program was divided into four separate investigations which included sulfate interaction in continuously fed contact reactors, sulfide-pH speciation effects, metal control of sulfide precipitation, and maximum kinetic measurements. During continuous fermenter operation, negligible effluent sulfate levels indicated that complete reduction of sulfate occurred with influent loadings

McFarland

1987-01-01

155

Bacteremia during barium enema study.  

PubMed

The occurrence of bacteremia was studied in patients undergoing barium enema. Blood cultures were done on 34 patients before, during, and after the procedure using two schedules. Cultures were obtained once during the procedure in the first schedule and four times in the second. None of the cultures were positive by the first schedule, while 23% of patients studied by the second schedule had one or more positive cultures. Organisms isolated were anaerobes. The bacteremia was transient and self-limited, without serious clinical sequelae. The incidence of bacteremia during barium enema examination was statistically indistinguishable from bacteremia previously reported during colonscopy. It is concluded that antibiotic prophylaxis is not indicated in most patients undergoing colonic diagnostic procedures. Prophylaxis in selected high-risk patients requires further study. PMID:416682

Butt, J; Hentges, D; Pelican, G; Henstorf, H; Haag, T; Rolfe, R; Hutcheson, D

1978-04-01

156

Barium in planktonic foraminifera  

SciTech Connect

Reconstructions of Ba distributions in ancient oceanic surface waters could provide new insight into paleoceanographic change. Calcite shells of planktonic foraminifera potentially provide a means of reconstructing such paleo-Ba distributions if lattice-bound Ba can be determined on shells recovered from deep-sea cores. Planktonic foraminifera shells from a series of cores were purified of non-lattice-bound Ba associated with organic or sedimentary phases by a combination of physical agitation, oxidative-reductive steps, acid leaches, and a novel alkaline-DTPA step to dissolve barite. A sequential dissolution of a large sample of cleaned shells of the planktonic foraminifer Globigerinoides conglobatus indicates homogeneous distribution of Ba in the shell material. Comparison of shells from sediments, sediment traps, and plankton tows indicates no significant differences in the Ba content of the purified shells. Variation in foraminiferal Ba contents between the Pacific, Atlantic, and Mediterranean Sea is consistent with the trend in surface seawater Ba. The calculated distribution coefficient for Ba incorporation in five species based on these data is 0.19 {plus minus} 0.05. Several species of the non-spinose planktonic foraminifera Globorotalia have Ba/Ca ratios ranging from 2 to 13 {mu}mol; these high Ba contents might be explained by differences in the way these foraminifera precipitate their shells. A temporal record of Ba/Ca in samples of Globigerinoides and Orbulina from a core in the northwest Atlantic suggests that the Ba concentration of surface waters at this site has not changed by more than 20% over the last 14 kyr.

Lea, D.W.; Boyle, E.A. (Massachusetts Inst. of Tech., Cambridge (United States))

1991-11-01

157

Yttrium and barium in open clusters  

NASA Astrophysics Data System (ADS)

Based on the VLT high-resolution spectra for stars of five open clusters: Ruprecht 4, Ruprecht 7, Berkeley 25, Berkeley 73, and Berkeley 75 (G. Carraro et al., 2007) we determined the yttrium and barium abundances using the synthetic-spectrum method. Barium abundance was calculated under a non-LTE approximation. We analyzed the correlation between yttrium and barium abundances and the ages of open clusters and stars of the Galactic thin disk.

Mishenina, T. V.; Korotin, S. A.; Yegorova, I. A.; Kovtukh, V. V.; Carraro, G.

2013-06-01

158

40 CFR 721.10011 - Barium calcium manganese strontium oxide.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Barium calcium manganese strontium oxide. ...Chemical Substances § 721.10011 Barium calcium manganese strontium oxide. ...The chemical substance identified as barium calcium manganese strontium...

2010-07-01

159

40 CFR 721.10011 - Barium calcium manganese strontium oxide.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false Barium calcium manganese strontium oxide. ...Chemical Substances § 721.10011 Barium calcium manganese strontium oxide. ...The chemical substance identified as barium calcium manganese strontium...

2009-07-01

160

40 CFR 721.10011 - Barium calcium manganese strontium oxide.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Barium calcium manganese strontium oxide. 721.10011...Chemical Substances § 721.10011 Barium calcium manganese strontium oxide. (a...chemical substance identified as barium calcium manganese strontium oxide (PMN...

2013-07-01

161

75 FR 20625 - Barium Chloride From China  

Federal Register 2010, 2011, 2012, 2013

...INTERNATIONAL TRADE COMMISSION [Investigation No. 731-TA-149 (Third Review)] Barium Chloride From China AGENCY: United States International Trade Commission. ACTION: Revised schedule for the subject...

2010-04-20

162

Redox processes in highly yttrium-doped barium titanate  

NASA Astrophysics Data System (ADS)

The changes of microstructure occurring during oxidation of the reduced form of yttrium-doped barium titanate (Ba1-xYxTi1-x4+Tix3+O3) have been studied. Samples were sintered under reduction conditions at PO2=10-4Pa and oxidized by annealing at high temperatures (1150 and 1350 °C) in air. Depending on yttrium concentration, the oxidation of the reduced form of the yttrium-doped BaTiO3 caused precipitation of the phase Ba6Ti17O40 or the phases Ba6Ti17O40 and Y2Ti2O7. The precipitates had well-defined orientational relationships with the perovskite matrix. Oxidation of the reduced form of doped barium titanate results in formation of the phase Ba1-xYxTi1-x/44+(VTi'''')x/4O3 responsible for increase in the resistance of outer grain layers, which lie between grain boundaries and grain.

Belous, Anatolii; v'Yunov, Oleg; Kovalenko, Leonid; Makovec, Darko

2005-05-01

163

Redox processes in highly yttrium-doped barium titanate  

SciTech Connect

The changes of microstructure occurring during oxidation of the reduced form of yttrium-doped barium titanate (Ba{sub 1-x}Y{sub x}{sup ?}Ti{sub 1-x}{sup 4+}Ti{sub x}{sup 3+}O{sub 3}) have been studied. Samples were sintered under reduction conditions at P{sub O{sub 2}}=10{sup -4}Pa and oxidized by annealing at high temperatures (1150 and 1350 deg. C) in air. Depending on yttrium concentration, the oxidation of the reduced form of the yttrium-doped BaTiO{sub 3} caused precipitation of the phase Ba{sub 6}Ti{sub 17}O{sub 40} or the phases Ba{sub 6}Ti{sub 17}O{sub 40} and Y{sub 2}Ti{sub 2}O{sub 7}. The precipitates had well-defined orientational relationships with the perovskite matrix. Oxidation of the reduced form of doped barium titanate results in formation of the phase Ba{sub 1-x}Y{sub x}{sup ?}Ti{sub 1-x/4}{sup 4+}(V{sub Ti}{sup -}bar ){sub x/4}O{sub 3} responsible for increase in the resistance of outer grain layers, which lie between grain boundaries and grain.

Belous, Anatolii [Department of Solid State Chemistry, V.I. Vernadskii Institute of General and Inorganic Chemistry, Ukrainian National Academy of Sciences, Institute of General and Inorganic Chemistry, 32/42, Palladin Ave, 03680 Kyiv 142 (Ukraine); V'yunov, Oleg [Department of Solid State Chemistry, V.I. Vernadskii Institute of General and Inorganic Chemistry, Ukrainian National Academy of Sciences, Institute of General and Inorganic Chemistry, 32/42, Palladin Ave, 03680 Kyiv 142 (Ukraine)]. E-mail: vyunov@ionc.kar.net; Kovalenko, Leonid [Department of Solid State Chemistry, V.I. Vernadskii Institute of General and Inorganic Chemistry, Ukrainian National Academy of Sciences, Institute of General and Inorganic Chemistry, 32/42, Palladin Ave, 03680 Kyiv 142 (Ukraine); Makovec, Darko [Jozef Stefan Institute, Ljubljana (Slovenia)

2005-05-15

164

New barium ferrite particles: Spherical shape  

NASA Astrophysics Data System (ADS)

Pure and ZnTi-doped spherical barium ferrite particles were prepared using two different methods: semicoprecipitation and ultrasonic spray pyrolysis. The ultrasonic spray pyrolysis method was more effective in controlling particle shape. Particle size was in between 0.27 and 0.3 ?m. Coercivity and saturation magnetization were in the range of 1000 to 5000 Oe and 49 to 53 emu/g, respectively. Crystallization of amorphous Ba-Fe-O spherical precursors occurs at a lower temperature than Ba-Fe-Zn-Ti-O precursors. ?M measurement shows that magnetic interaction in spherical barium ferrite tape is weaker than hexagonal platelet barium ferrite.

Hong, Y. K.; Jung, H. S.

1999-04-01

165

New pressure flow cell to monitor BaSO4 precipitation using synchrotron in situ angle-dispersive X-ray diffraction.  

PubMed

A flow cell has been commissioned to monitor in situ precipitation reactions under non-ambient conditions. The majority of high-pressure systems use anvils and presses to obtain high pressures around a small reaction area; however, this prototype is unique in that solutions may be examined as they flow through the cell under pressure. The cell is made of single-crystal silicon, which is capable of withstanding the high pressures created by liquid flow within the cell. With the capability of reaching pressures of up to 4 x 10(7) Pa, the cell is ideal for work on geological and oilfield systems. Here it is used to examine the formation of barium sulfate scale in situ under non-ambient conditions using angle-dispersive XRD on beamline X17b1 at the NSLS. PMID:12200578

Hennessy, Alison; Graham, Gordon; Hastings, Jerry; Siddons, D Peter; Zhong, Zhong

2002-08-31

166

Broad band absorbance of barium hexaferrite thick films in the 8-12 GHz frequency spectrum  

Microsoft Academic Search

Screen printed barium hexaferrite thick films on alumina with broad band absorbance in the X band were fabricated. BaFe12O19 was synthesized using a cost effective low temperature co-precipitation method with varying Fe\\/Ba molar ratio and pH. The\\u000a thick film showed increased grain size for higher Fe\\/Ba molar ratio. The complex permittivity and permeability of these thick\\u000a films showed wavelike behavior

D. C. Kulkarni; Vijaya Puri

2011-01-01

167

Oxidation of alkaline earth sulfides to sulfates: Thermodynamic aspects  

Microsoft Academic Search

The emf of the galvanic cell, Pt, Ni + NiO\\/(CaO) ZrO2\\/MS + MSO4, Ir, Pt, where M is calcium, strontium, or barium, has been measured in the temperature range 850 to 1100 K. From these measurements\\u000a the Gibbs’ energy changes for the oxidation of sulfides of alkaline earth metals to their respective sulfates have been calculated.\\u000a The results are compared

K. T. Jacob; G. N. K. Iyengar

1982-01-01

168

Freezing Precipitation.  

National Technical Information Service (NTIS)

This technical note discusses three advection patterns favorable for freezing precipitation. Two graphs were developed based on 503 freezing precipitation occurrences during the past 11 years- a 1000- to 500-mb thickness graph and an 850-mb temperature gr...

E. M. Weber

1998-01-01

169

Removal of Barium and Radium from Groundwater.  

National Technical Information Service (NTIS)

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 fr...

V. L. Snoeyink C. C. Chambers C. K. Schmidt R. F. Manner A. G. Myers

1987-01-01

170

Deflocculants for Tape Casting Barium Titanate Dielectrics.  

National Technical Information Service (NTIS)

The tape casting slip composition barium titanate powder, MEK-Ethanol solvent, phosphate ester dispersant, acrylic binder, PEG and butyl-benzyl-phthalate plasticizers and cyclohexanone was studied. The nature of the dispersion mechanism for the phosphate ...

W. R. Cannon

1985-01-01

171

Dielectric and Piezoelectric Properties of Barium Titanate  

Microsoft Academic Search

The dielectric constant and loss of barium titanate and barium-strontium titanate have been measured at biasing field strengths from 0 to 5 megavolts per meter, at temperatures from -50°C to +135°C and at frequencies from 0.1 to 25 megacycles. The measurements versus temperature indicate the expected agreement with the Curie-Weiss law at temperatures above the Curie point. Measurements versus field

Shepard Roberts

1947-01-01

172

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

173

Biological sulfate removal in an upflow packed-bed reactor  

SciTech Connect

A biological process for the removal of sulfate, using molasses as organic carbon source, is described. Sulfate is converted to sulfur via sulfide, and molasses to bicarbonate. The process is accompanied by the precipitation of calcium carbonate and heavy-metal sulfides. Sulfate reduction follows zero-order kinetics with respect to both reactants and products. The reduction of 1 g sulfate consumes 1,2 ml molasses and requires 6 h for completion. The Darcian minimum upflow velocity for sulfate reduction in an anaerobic packed-bed reactor was found to be 1,3 m/h and the optimum temperature 31 C.

Maree, J.P.; Strydom, W.F.

1984-01-01

174

The rise and phalli of barium stars  

NASA Astrophysics Data System (ADS)

Barium stars are thought to be formed by accretion of material from the wind of an s-process-rich asymptotic giant branch star onto a main sequence star in a binary system. The accretor then evolves up the giant branch and, as it cools, absorption lines of barium are prominent in its spectrum. This is the barium star we see today. Barium stars are excellent probes of binary-star physics because orbital periods and eccentricities are known for nearly all of them, i.e. the sample set is complete. Binary-star theory predicts that barium stars with periods shorter than a few thousand days should circularise by tidal interaction, but the observed stars are often highly eccentric. We investigate a potential source of their eccentricity: white dwarf kicks. We can reproduce the observed period-eccentricity distribution if we introduce a moderate kick speed of a few km/s together with efficient angular momentum loss in stellar winds and efficient common-envelope ejection. Many open questions remain which are key to the wind-accretion mechanism by which barium stars and other chemically-peculiar binaries such as CH and carbon-enhanced metal-poor (CEMP) stars form.

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

175

Analysis of precipitation chemistry at a central Pennsylvania site  

NASA Astrophysics Data System (ADS)

As part of the multistate atmospheric power production pollution study precipitation chemistry network, precipitation has been sampled on a storm-by-storm basis at a rural central Pennsylvania site operated by Pennsylvania State University since October 1976. These precipitation data have been analyzed for sulfate, nitrate, ammonium, and hydronium ions for the years 1977 and 1978, and both years exhibit the same general behavior with respect to these chemical species: (1) sulfate concentration in precipitation varies with season, with high values in the summer and low values in the winter, (2) sulfate ion is the major determinant of precipitation acidity, though sulfate alone does not account for the total H3O+ concentration, (for snow and other frozen precipitation the relation between sulfate and H3O+ is less pronounced), (3) nitrate ion of concentrations similar to those of sulfate does not correlate well with hydronium ion in liquid precipitation but does correlate with H3O+ in snow and frozen precipitation, and (4) ammonium ion concentrations in precipitation can be explained by assuming an equilibrium state between the cloud water and gas phase ammonia.

Bowersox, Van C.; de Pena, Rosa G.

1980-10-01

176

Diacetamidinium sulfate  

PubMed Central

In the crystal structure of the title compound, 2C2H7N2 +·SO4 2?, which contains four cations and two anions in the asymmetric unit, the ions are inter­connected by an extensive hydrogen-bonding system whereby two of the O atoms of sulfate ion are hydrogen-bonded to the amidinium H atoms of two cations, leading to the formation of two eight-membered rings. The two remaining O atoms inter­connect two H atoms of acetamidinium cations, forming an infinite chain. The C?N separations within the H2N?C?NH2 moieties are similar, with an average value of 1.305?(2)?Å, which is in good agreement with a delocalization model.

Jalovy, Zdenek; Ruzicka, Ales

2010-01-01

177

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

National Technical Information Service (NTIS)

This study examines how several different parameters were changed in the yttrium-barium-copper oxide superconductor when the fabrication techniques were altered by using different barium precursors, including barium peroxide and barium carbonate; sinterin...

P. A. Rhea

1988-01-01

178

Barium Cycling During the Paleocene-Eocene Thermal Maximum: Evidence From Ba/Ca in Foraminifera  

NASA Astrophysics Data System (ADS)

The Paleocene-Eocene thermal maximum (PETM) around 55 Ma reflects short-term, rapid climate change during a period of intense greenhouse climate. This interval is characterized by a negative carbon isotopic shift, interpreted as a release of methane from seafloor gas hydrate reservoirs. This perturbation of the carbon cycle is accompanied by significantly greater rates of euhedral barite accumulation in deep sea sediment commonly believed to be a reflection of elevated primary productivity in surface waters. An interpretation of higher productivity during the PETM, however, is contrary to microfossil assemblage data which indicates a decrease in primary productivity. It has also been suggested that the increase in barite accumulation during the PETM may have been the result of an increase in dissolved barium concentrations in the deep ocean coeval with methane release. This supposition has support from the fact that modern gas hydrate reservoirs are surrounded by pore waters with dissolved barium concentrations considerably higher than that of seawater. This investigation utilizes the barium content of foraminifera as a proxy to reconstruct changes in the barium concentration of the ocean. At 55 Ma, Ba/Ca decreases between 25 to 28% in the planktic foraminifer \\textit{Morozovella velascoensis}, indicating a decrease in the barium concentration of the surface ocean. These results bolster the theory that there was increased biogenic barite precipitation during the PETM. Changes in surface water temperature and pH may have altered species assemblages such that celestite (SrSO4) precipitating organisms enriched in barium as BaSO4 (possibly acantharia) were dominant, modifying the barite precipitation pathways, which affected water column barite cycling. Ba/Ca and Cd/Ca measurements on benthic foraminifera show a positive correlation with Mn/Ca, indicating contamination of manganese oxide coatings. This contamination is in part due to the greater surface to volume ratio of benthic foraminifera, which are smaller than planktic species. Additionally, smaller quantities of benthics were available for analysis, which limited the intensity of pre-treatment to remove these coatings. After correcting for this coating contamination, no significant change in benthic Ba/Ca could be discerned through this interval. Taken together, the planktic and benthic foraminiferal Ba/Ca data suggests that enhanced biogenic barite accumulation during the PETM was primarily due to increased export from the surface waters.

Hall, J. M.; Zachos, J. C.; Turekian, K. K.

2004-12-01

179

Elemental sulfur dynamics in acid sulfate soil landscapes  

Microsoft Academic Search

The precipitation and dissolution of iron and sulfur minerals has a primary influence on water quality of acid sulfate affected landscapes (Fanning et al. 2002; Nordstrom 2000). The two key processes involved are the microbially mediated reduction and oxidation of sulfate and iron (Peine et al. 2000), which drive the geochemical store and flux of acidity. Iron sulfide minerals are

Richard T Bush; Edward D Burton; Leigh A Sullivan; Salirian R Claff

2006-01-01

180

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...

181

Effects of barium chlorine treatment of uranium ore on /sup 222/Rn emanation and /sup 226/Ra leachability from mill tailings  

SciTech Connect

The purpose of this laboratory study was to investigate the effectiveness of barium chloride treatment of uranium ore on /sup 222/Rn emanation from mill tailings, /sup 226/Ra level in waste-water, and the leachability of radium from tailings. It has been shown that barium sulfate is an excellent carrier for radium and that barium sulfate crystals have high retention capacity for radon gas produced by radium trapped within the lattice. Ground uranium ore from a mine in Wyoming was mixed with water to form a 1:1 ratio before barium and potassium chlorides were added at concentrations of 0, 10, 25, 50, and 100 mg per liter of slurry. The ore was then subjected to a simulated mill process using sulfuric acid leaching. The liquid representing tailings pond water was separated and analyzed for /sup 226/Ra and the solid fraction, representing mill tailings, was tested for radon emanation and the leachability of radium by deionized water. This study suggests that barium treatment of uranium ore prior to sulfuric acid leaching could be effective in reducing radon emanation from tailings and also in reducing the /sup 226/Ra concentration of waste-water. Leachability of radium from treated tailings was markedly reduced.

Ibrahim, S.A.; Church, S.L.; Whicker, F.W.

1985-01-01

182

Trends in pH, calcium, and sulfate of rivers in Atlantic Canada  

Microsoft Academic Search

Acid precipitation is affecting the chemistry of rivers in Atlantic Canada. Long term records for pH, calcium, and sulfate from 11 rivers were fitted using time series models. Decreases in pH over time were found, but the results for calcium and sulfate were not consistent with the predicted model. The conceptual models used to understand the effects of acid precipitation

THOMAS A. CLAIR; PAUL H. WHITFIELD

1983-01-01

183

Sulfate Removal from Water  

Microsoft Academic Search

Sulfate occurs naturally in groundwater. Concerns regarding the health effects from sulfate in drinking water have been raised because of reports that diarrhea may be associated with water that contains high levels of sulfate. In the live- stock production industry, there is a concern that high levels of sulfate in water can adversely affect productivity. Different methods can be used

ASHREF DARBI; THIRUVENKATACHARI VIRARAGHAVAN; YEE-CHUNG JIN; LARRY BRAUL; DARRELL CORKAL

184

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

185

Precipitation research  

Microsoft Academic Search

Major flood events during the past 4 yr in the United States have focused attention on the need for additional research relating to the measurement and estimation of areal distribution of precipitation. The characteristics of the precipitation associated with the storms that produced the major floods varied widely. Major flooding occurred over a large area of the lower Mississippi River

Eugene L. Peck

1975-01-01

186

Precipitation Rate  

NSDL National Science Digital Library

A GIF or Flash animation displays the actual monthly amount of precipitation (mm) reaching the surface. Focus on seasonal changes in precipitation associated with the north-south movement of the Intertropical Convergence Zone (ITC) in Africa and monsoonal patterns on the Indian subcontinent. In the Flash format, the animation can easily be rewound or paused to stress important points.

Climvis.org

187

Effects of solution sulfate, hydroxide, and potassium concentrations on the crystallization of alunite, basaluminite, and gibbsite from dilute aluminum solutions  

Microsoft Academic Search

Solution experiments were conducted in which basic aluminum sulfates were precipitated from dilute solutions of various concentrations of sulfate and potassium at different pHs. Aging of precipitates at 50°C for 18 weeks resulted in crystalline precipitates of gibbsite, basaluminite, alunite, or mixtures of these minerals. The results suggest that sulfate in acid soil solutions will react in a similar manner

FRED ADAMS; B. F. Hajek

1978-01-01

188

Bioremediation of acid mine water using facultatively methylotrophic metal-tolerant sulfate-reducing bacteria  

Microsoft Academic Search

A microbial process is proposed for the decontamination of acid uranium mine water high in sulfates and metals. Sulfate reducers are suitable for such a process. Anaerobic reduction of sulfate results in the formation of H2S which leads to an increase in pH and the precipitation of the metals. As cheap an readily available carbon and energy source methanol was

Barbara C. Hard; S. Friedrich; W. Babel

1997-01-01

189

Particulate barium fluxes and their relationships to biological productivity  

Microsoft Academic Search

To understand better the processes that control the transport of particulate barium through the water column and its preservation in marine sediments, we measured particulate barium fluxes along an equatorial transect at 140°W using moored sediment traps. The fluxes of barium correlate strongly with the fluxes of organic carbon; however, this relationship is non-linear—higher carbon fluxes have proportionately less associated

Jack Dymond; Robert Collier

1996-01-01

190

Precipitation Protocols  

NSDL National Science Digital Library

The purpose of this activity is to determine the amount of moisture input to the local environment by measuring rain and snowfall and to measure the pH of precipitation. To do so students use a rain gauge and a snowboard to measure the daily amount of precipitation. Special pH measuring techniques for precipitation are used to determine the pH of rain and melted snow. Intended outcomes are that students will understand that precipitation is measured in depth and this depth is assumed to apply to a large area, that precipitation has a pH that can vary, and that snow is an input of water to the surface just like rain and each snowfall is equivalent to some amount of rainfall. Supporting background materials for both student and teacher are included.

The GLOBE Program, UCAR (University Corporation for Atmospheric Research)

2003-08-01

191

Barium titanate fabricated from fur-fibres  

Microsoft Academic Search

Long-fibrous barium titanate (BaTiO3) particles were prepared by a hydrothermal reaction of potassium titanate hydrate (2K2O·11TiO2·3H2O) and barium hydroxide (Ba(OH)2). Effects of preparation conditions on crystal structure and powder morphology were examined. Fur-fibres of K2O·4TiO2, 1–10 mm long and 1–100 ?m in diameter, were obtained by heating a mixture of K2CO3 and TiO2 powders at 1000 ‡C for 100 h.

Yoshinobu Ohara; Masaru Miyayama; Tadao Shimizu; Hiroaki Yanagida

1996-01-01

192

STABILIZED BARIUM TITANATE CERAMICS FOR CAPACITOR DIELECTRICS  

Microsoft Academic Search

The effects of additions of LaâOâ and LaâOâ--; 3TiOâ on the electronic properties of barium titanate were investigated. ; It was found that small additions of the components markedly increase the ; lifetime of the material subjected to d-c fields of 50 v per mil at 200 l ; C. (auth);

J. B. MacChesney; P. K. Gallagher; F. V. DiMarcello

1963-01-01

193

Prospects for Barium Tagging in Gaseous Xenon  

Microsoft Academic Search

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

D. Sinclair; E. Rollin; J. Smith; A. Mommers; N. Ackerman; B. Aharmim; M. Auger; P. S. Barbeau; C. Benitez-Medina; M. Breidenbach; A. Burenkov; S. Cook; A. Coppens; T. Daniels; R. DeVoe; A. Dobi; M. J. Dolinski; K. Donato; Fairbank W. Jr; J. Farine; G. Giroux

2012-01-01

194

Low Temperature Thermal Expansion of Barium Ferrite.  

National Technical Information Service (NTIS)

The linear thermal expansion of polycrystalline barium ferrite, BaFe12O19, was measured from 76 to 293 K both parallel and perpendicular to the magnetization direction. An anisotropy of about 15-20% was observed. The results match well the available data ...

A. F. Clark W. M. Haynes V. A. Deason R. J. Trapani

1975-01-01

195

Deflocculants for Tape Casting Barium Titanate Dielectrics.  

National Technical Information Service (NTIS)

The first part of this study has been directed towards understanding the mechanisms of dispersion for barium titanate in a methylathyl ketone-ethanol system using a commercial phosphate ester dispersant. The dispersant was found to be very effective in lo...

W. R. Cannon

1986-01-01

196

Deflocculants for Tape Casting Barium Titanate Dielectrics.  

National Technical Information Service (NTIS)

A typical nonaqueous tape casting system based on a commercial acrylic binder was studied to understand the system in more depth. The following conclusions were drawn: The best surfactants for dispersing barium titanate in the MEK-ethanol solvent system a...

W. R. Cannon

1988-01-01

197

Acid Precipitation  

NSDL National Science Digital Library

Acid precipitation will be defined. At different points in the lesson students will write balanced reactions for the formation acid precipitation from atmospheric sulfur and nitrogen oxides and the neutralization of acids by limestone. Students will determine which states are most at risk from acid precipitation and assess how that risk has changed from 1996 to 2006. Sources of atmospheric sulfur (burning of high-sulfur coal) and nitrogen oxides (automobile exhaust) will be listed. The buffering effect of limestone soils and its mitigating effect on acid precipitation will be discussed. Students will correlate these areas with sulfur and nitrogen oxide production, population, composition of coal fields, and soil composition. This resource includes both a teaching guide and student worksheets.

Tyser, Jim

2011-09-15

198

Treatment of recycled ammonium sulfate-bisulfate solution  

Microsoft Academic Search

Ammonium sulfate-bisulfate solution contaminated with metal and other ash producing contaminants is treated by adjusting the pH of the solution to the range that produces a precipitate of the contaminant by the addition of ammonia or ammonium hydroxide; cooled to at least the temperature at which a precipitate is produced; removing the precipitate from the solution; the pH of the

Benedict

1980-01-01

199

Effect of Chondroitin 6-Sulfate on the Quaternary Structure of Collagen and on Its Reaction with Platelets.  

National Technical Information Service (NTIS)

The effect of addition of chondroitin 6-sulfate on the quaternary structure of the collagen fibrils precipitated from the dispersed state was studied. Transmission electron microscopy of collagen fibrils precipitated by a variety of procedures clearly sho...

I. V. Yannas F. H. Silver E. W. Salzman

1977-01-01

200

STRONTIUM PRECIPITATION  

DOEpatents

A process is given for improving the precipitation of strontium from an aqueous phosphoric-acid-containing solution with nickel or cobalt ferrocyanide by simultaneously precipitating strontium or calcium phosphate. This is accomplished by adding to the ferrocyanide-containing solution calcium or strontium nitrate in a quantity to yield a concentration of from 0.004 to 0.03 and adjusting the pH of the solution to a value of above 8.

McKenzie, T.R.

1960-09-13

201

Microcapsules with intrinsic barium radiopacity for immunoprotection and X-ray/CT imaging of pancreatic islet cells.  

PubMed

Microencapsulation is a commonly used technique for immunoprotection of engrafted therapeutic cells. We investigated a library of capsule formulations to determine the most optimal formulation for pancreatic beta islet cell transplantation, using barium as the gelating ion and clinical-grade protamine sulfate (PS) as a new cationic capsule cross-linker. Barium-gelated alginate/PS/alginate microcapsules (APSA, diameter = 444 ± 21 ?m) proved to be mechanically stronger and supported a higher cell viability as compared to conventional alginate/poly-l-lysine/alginate (APLLA) capsules. Human pancreatic islets encapsulated inside APSA capsules, gelated with 20 mm barium as optimal concentration, exhibited a sustained morphological integrity, viability, and functionality for at least 3-4 weeks in vitro, with secreted human C-peptide levels of 0.2-160 pg/ml/islet. Unlike APLLA capsules that are gelled with calcium, barium-APSA capsules are intrinsically radiopaque and, when engrafted into mice, could be readily imaged in vivo with micro-computed tomography (CT). Without the need of adding contrast agents, these capsules offer a clinically applicable alternative for simultaneous immunoprotection and real-time, non-invasive X-ray/CT monitoring of engrafted cells during and after in vivo administration. PMID:22444642

Arifin, Dian R; Manek, Sameer; Call, Emma; Arepally, Aravind; Bulte, Jeff W M

2012-03-22

202

PRECIPITATION METHOD OF SEPARATING PLUTONIUM FROM CONTAMINATING ELEMENTS  

DOEpatents

S>A method is described for separating plutonium, in a valence state of less than five, from an aqueous solution in which it is dissolved. The niethod consists in adding potassium and sulfate ions to such a solution while maintaining the solution at a pH of less than 7.1, and isolating the precipitate of potassium plutonium sulfate thus formed.

Duffield, R.B.

1959-02-24

203

Immunoaffinity centrifugal precipitation chromatography.  

PubMed

Purification of proteins based on immunoaffinity has been performed using a solid support coated with antibody against the target proteins. The method requires immobilizing the antibody onto the solid support using protein A or G, and has a risk of adsorptive loss of target proteins onto the solid support. Centrifugal precipitation chromatography has been successfully used to purify enzymes, such as ketosteroid isomerase and hyaluronidase without the use of solid support. The purpose of this study is to demonstrate that immunoaffinity centrifugal precipitation chromatography is capable of isolating an antigen by exploiting antigen-antibody binding. The separation was initiated by filling both channels with 40% saturated ammonium sulfate (AS) of pH 4-4.5 followed by loading 20 microl of human plasma (National Institutes of Health blood bank) mixed with 2 mg of rabbit anti-HSA (human serum protein) antibody (Sigma). Then, the sample channel was eluted with water at 0.03 ml/min and AS channel with 40% AS solution of pH 4-4.5 at 1 ml/min until all non-binding components were eluted. Then, the releasing reagent (50% AS solution containing 0.5 M glycine and 10% ammonium hydroxide at pH 10) was introduced through the AS channel to release the target protein (HSA). The retained antibody was recovered by eluting the sample channel with water at 1 ml/min. A hollow fiber membrane device at the outlet (MicroKros, Spectrum, New Brunswick, NJ, USA) was provided on-line dialysis of the eluent before fractions were collected, so that the fractions could be analyzed by SDS-PAGE (sodium dodecyl sulfate - polyacrylamide gel electrophoresis) without further dialysis. The current method does not require immobilizing the antibody onto a matrix, which is used by the conventional immunoaffinity chromatography. This method ensures full recovery of the antigen and antibody, and it may be applied to purification of other proteins. PMID:17416378

Qi, Lin; Ito, Yoichiro

2007-03-30

204

High-field conduction in barium titanate  

NASA Astrophysics Data System (ADS)

We present current-voltage studies of very thin (~77 nm) barium titanate single crystals up to 1.3 GV/m applied field. These show that the mechanism of leakage current at high fields is that of space charge limited conduction (SCLC) in a regime with a continuous distribution of traps, according to the original model of Rose [Phys. Rev. 97, 1538 (1955)]. This study represents a factor of ×5 in field compared with the early studies of BaTiO3 conduction [A. Branwood et al., Proc. Phys. Soc. London 79, 1161 (1962)]. Comparison is also given with ceramic multilayer barium titanate capacitors, and with variable range hopping [B. I. Shklovskii, Sov. Phys. Semicond. 6, 1964 (1973)], reported in SrTiO3 films [D. Fuchs, M. Adam, and R. Schneider, J. Phys. IV France 11, 71 (2001)].

Morrison, F. D.; Zubko, P.; Jung, D. J.; Scott, J. F.; Baxter, P.; Saad, M. M.; Bowman, R. M.; Gregg, J. M.

2005-04-01

205

A self-sustaining acid-base reaction in semi-aqueous media for synthesis of barium titanyl oxalate leading to BaTiO 3 powders  

Microsoft Academic Search

A self-sustaining controlled acid–base reaction between oxalotitanic acid [H2TiO(C2O4)2] (HTO) and barium hydroxide [Ba(OH)2·8H2O] at room temperature is utilized for the quantitative precipitation of barium titanyl oxalate (BTO). For this purpose, an intermediate soluble oxalotitanic acid precursor is generated by reacting 0.1 M solution of titanium tetrabutoxide in isopropanol (IPA) with 0.2 M solution of oxalic acid in IPA. Equimolar

Y. B Khollam; A. S Deshpande; H. S Potdar; S. B Deshpande; S. K Date; A. J Patil

2002-01-01

206

Electrical properties of polycrystalline PTCR barium titanate  

Microsoft Academic Search

Semiconducting n-type barium titanate with a positive temperature coefficient of resistance (PTCR) has been made by doping BaTiO3 with 0.4 mol% Ho2O3. The d.c. resistivity, a.c. resistivity (1.2 kHz) and relative permittivity (1.2 kHz) at different temperatures between room temperature and 523 K have been measured. The high relative permittivity and the PTCR effect are attributed to the existence of

M. A. A. Issa

1992-01-01

207

Densities of liquid metals: calcium, strontium, barium  

Microsoft Academic Search

We report a method of measuring the densities of liquids at intermediate temperatures which employs Archimedes' Principle in a two-sinker arrangement. This method is then used to measure the densities of pure liquid calcium, strontium, and barium. We find ?(Ca) = 1.4931 ? 1.37 × 10 T(°C) from 850 ? 950°C, ?(Sr) = 2.5547 ? 2.83 × 10 T(°C) from

S. Hiemstra; D. Prins; G. Gabrielse; J. B. Van Zytveld

1977-01-01

208

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

209

Electrical properties of barium-borosilicate glasses  

Microsoft Academic Search

Bulk and thin-blown films of barium-borosilicate glass were prepared and their electrical conduction properties at high and\\u000a low fields were measured as functions of temperature. The electrical conductivity is an exponential function of inverse temperature\\u000a at high temperatures with an activation energy in the range 1.0 to 1.4 eV, depending on composition. The conduction process\\u000a is believed to involve polarons

G. R. Moridi; A. Nouruzi; C. A. Hogarth

1991-01-01

210

Aqueous processing of barium titanate powders  

Microsoft Academic Search

In many modern electronic devices, multi-layer ceramic capacitors (MLCCs) are used in large quantities. For a greater volume efficiency of MLCCs, current efforts include thinner dielectric layers and a larger number of layers in a given volume, togethe r with embedded-capacitor design. All of these require a smaller particle size of the raw ceramic material, barium titanate (BaTiO3) powders, with

B. I. Lee; M. Wang; D. Yoon; M. Hu

2003-01-01

211

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

212

Electrostatic precipitator  

Microsoft Academic Search

An electrostatic precipitator is described that has a rotor supported for rotation within a housing containing inlet and outlet openings adjacent the opposite ends. The rotor is formed by a plurality of ringlike collector plates which are fixedly connected in axially spaced relationship. One end of the rotor, as disposed adjacent the outlet opening, is closed by a support plate.

Ahlrich

1978-01-01

213

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

214

Development of barium tagging technology for EXO  

NASA Astrophysics Data System (ADS)

The Enriched Xenon Observatory (EXO) is a series of experiments designed to search for the neutrinoless double beta decay of Xenon-136. The first experiment, known as EXO-200, is comprised of a liquid xenon TPC containing 200 kg of xenon enriched to 80% in Xenon-136 and is nearing completion. To suppress possible radioactive backgrounds, the EXO collaboration is also pursuing the development of a new technique to identify the production of the barium daughter ions produced by double beta decay. For this purpose, a linear radio-frequency ion trap has been constructed. Individual barium ions are trapped in this helium or argon buffer gas-filled trap and observed with a high signal-to-noise ratio by resonance fluorescence. Furthermore, two ion transfer methods are under parallel development, both involving the capture and transport of the ions on the surface of a specially designed tip. This talk will present the results obtained in the trapping of single buffer gas-cooled barium ions and the transfer of ions using a cryogenic tip, and our plans for an ion transfer tip using resonance ionization spectroscopy.

Montero Diez, Maria

2008-04-01

215

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

216

Chemistry of precipitation in north-central Florida  

Microsoft Academic Search

Chemical analyses of atmospheric precipitation collected during 1976-1977, at locations in north-central Florida, indicate that the atmosphere is a significant source of elements to terrestrial and aquatic ecosystems. On an average weighted concentration basis which takes into account the amount of precipitation as well as the ionic concentration, sulfate, chloride, and nitrate were the predominant anions, comprising 52 percent, 27

Hendry; C. D. Jr

1977-01-01

217

Iron availability in mixed cultures of sulfate-reducing bacteria  

SciTech Connect

Postgate's medium C was found to be unsuitable for quantitative studies of mixed microbial cultures containing sulfate-reducing bacteria. Equilibrium calculations of iron concentration, along with the experimental observations show that precipitation of iron occurs in Postgate's medium, despite the presence of citrate and yeast extract. The often ascribed inhibitory effect of sulfide on the growth of sulfate-reducing bacteria may be largely due to the reduced availability of iron, as a result of the precipitation of ferrous sulfide. Because it is essential to clearly define the growth limiting nutrient when carrying out quantitative bacterial growth studies, yeast extract should be excluded from the culture medium. Single-phase, exponential growth was observed for mixed cultures containing sulfate-reducing bacteria, using a chemically defined medium that incorporated the metal complexing agent EDTA. When carrying out quantitative kinetic studies of sulfate-reducing bacteria, a chemically defined medium incorporating EDTA is recommended.

Hauser, J.Y.; Holder, G.A.

1986-01-01

218

Method of treating lake water with aluminum hydroxide sulfate  

US Patent & Trademark Office Database

A method of treating lake water to remove suspended solids and to precipitate and inactivate phosphorus comprises adding aluminum hydroxide sulfate to the water in a concentration such that the pH of the water is maintained at a level of greater than 6.0 and precipitation of suspended solids and precipitation and inactivation of phosphorus occurs. This invention is advantageous in that it provides a method of removing suspended solids as well as precipitating and inactivating phosphorus in water while simultaneously preventing the solublizing of toxic amounts of aluminum into the water with subsequent detrimental effects to aquatic life.

Conover; Brett R. (Switzerland, FL)

1991-08-13

219

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

220

Effect of Barium Loading on the Desulfation of Pt-BaO/Al2O3 Studied by H2 TPRX, TEM, Sulfur K-edge XANES, and in Situ TR-XRD  

SciTech Connect

Desulfation processes were investigated over sulfated Pt BaO/Al2O3 with different barium loading (8 wt% and 20 wt%) by using H2 temperature programmed reaction (TPRX), transmission electron microscope (TEM) with energy dispersive spectroscopy (EDS), sulfur K-edge X-ray absorption near-edge spectroscopy (XANES), and in situ time-resolved X-ray diffraction (TR-XRD) techniques. Both sulfated samples (8 wt% and 20 wt%) form sulfate species (primarily BaSO4) as evidenced by S K-edge XANES and in situ TR-XRD. However, the desulfation behavior is strongly dependant on the barium loading. Sulfated Pt BaO(8)/Al2O3, consisting predominantly of surface BaO/BaCO3 species, displays more facile desulfation by H2 at lower temperatures than sulfated Pt BaO(20)/Al2O3, a material containing primarily bulk BaO/BaCO3 species. Therefore, after desulfation with H2 up to 1073 K, the amount of the remaining sulfur species on the former, mostly as BaS, is much less than on the latter. This suggests that the initial morphology differences between the two samples play a crucial role in determining the extent of desulfation and the temperature at which it occurs. It is concluded that the removal of sulfur is significantly easier at lower barium loading. This finding can potentially be important in developing more sulfur resistant LNT catalyst systems.

Kim, Do Heui; Szanyi, Janos; Kwak, Ja Hun; Szailer, Tamas; Hanson, Jonathan; Wang, Chong M.; Peden, Charles HF

2006-06-01

221

Effect of barium loading on the desulfation of Pt-BaO/Al2O3 studied by H2 TPRX, TEM, sulfur K-edge XANES, and in situ TR-XRD.  

PubMed

Desulfation processes were investigated over sulfated Pt-BaO/Al2O3 with different barium loading (8 and 20 wt %) by using H2 temperature programmed reaction (TPRX), transmission electron microscope (TEM) with energy dispersive spectroscopy (EDS), sulfur K-edge X-ray absorption near-edge spectroscopy (XANES), and in situ time-resolved X-ray diffraction (TR-XRD) techniques. Both sulfated samples (8 and 20 wt %) form sulfate species (primarily BaSO4) as evidenced by S K-edge XANES and in situ TR-XRD. However, the desulfation behavior is strongly dependent on the barium loading. Sulfated Pt-BaO8/Al2O3, consisting predominantly of surface BaO/BaCO3 species, displays more facile desulfation by H2 at lower temperatures than sulfated Pt-BaO20/Al2O3, a material containing primarily bulk BaO/BaCO3 species. Therefore, after desulfation with H2 up to 1073 K, the amount of the remaining sulfur species on the former, mostly as BaS, is much less than that on the latter. This suggests that the initial morphology differences between the two samples play a crucial role in determining the extent of desulfation and the temperature at which it occurs. It is concluded that the removal of sulfur is significantly easier at lower barium loading. This finding can potentially be important in developing more sulfur resistant LNT catalyst systems. PMID:16722751

Kim, Do Heui; Szanyi, Janos; Kwak, Ja Hun; Szailer, Tamas; Hanson, Jonathan; Wang, Chong Min; Peden, Charles H F

2006-06-01

222

Roles of Pt and BaO in the Sulfation of Pt/BaO/Al2O3 Lean NOx Trap Materials: Sulfur K-edge XANES and Pt Llll XAFS Studies  

SciTech Connect

The roles of barium oxide and platinum during the sulfation of Pt-BaO/Al2O3 lean NOx trap catalysts were investigated by S K edge XANES (X-ray absorption near-edge spectroscopy) and Pt LIII XAFS (X-ray absorption fine structure). All of the samples studied [Al2O3, BaO(x; x = 8 or 20 wt %)/Al2O3, Pt(2.5 wt %)/Al2O3, and Pt(2 wt %)-BaO(x; x = 8 or 20 wt %)/Al2O3] were pre-sulfated prior to the X-ray absorption measurements. It was found that barium oxide itself has the ability to directly form barium sulfate even in the absence of Pt and gas-phase oxygen. In the platinum-containing samples, the presence of Pt-O species plays an important role in the formation of sulfate species. For the case of the BaO(8)/Al2O3 sample, where the barium coverage is about 0.26 ML, both baria and alumina phases are available for sulfation. S XANES results show that barium sulfates are formed preferentially over aluminum sulfates. When oxygen is absent from the gas phase, the sulfation route that involves Pt-O is eliminated after the initially present Pt-O species are completely consumed. In this case, formation of sulfates is suppressed unless barium oxide is also present. Pt LIII XAFS results show that the first coordination sphere around the Pt atoms in the Pt particles is dependent upon the gas mixture used during the sulfation process. Sulfation under reducing environments (e.g., SO2/H2) leads to formation of Pt-S bonds, while oxidizing conditions (e.g., SO2/O2) continue to show the presence of Pt-O bonds. In addition, a reducing environment was found to cause Pt sintering in greater extent than an oxidizing one. This result explains why samples sulfated under reducing conditions had lower NOx uptakes than those sulfated under oxidizing conditions. Therefore, our results provide needed information for the development of optimum practical operation conditions (e.g., sulfation or desulfation) for lean NOx trap catalysts that minimize deactivation by sulfur.

Kim,D.; Kwak, J.; Szanyi, J.; Cho, S.; Peden, C.

2008-01-01

223

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

224

Stoichiometry : PrecipYield (3 Variations)  

NSDL National Science Digital Library

In a laboratory experiment to determine accurately the amount of barium in solution, aqueous sulfuric acid was added to the solution to precipitate barium sulfate, which was then filtered and weighed. In this experiment it is MOST important that ...

225

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

226

Composition and structure measurements in an ionospheric barium cloud  

NASA Astrophysics Data System (ADS)

A 48 kg barium payload was launched from Eglin Air Force Base, Florida on 12 December 1980 at 2311 GMT and detonated at 183.7 km. At 2342:50.25 GMT, a second rocket, instrumented with an ion mass spectrometer and pulsed plasma probes, was fired to traverse the barium cloud. Composition, ion density, and structure measurements were acquired up to 241.2 km in both the natural and disturbed ionosphere. The rocket penetrated the barium cloud between 147 and 184 km. In addition to the Ba+, Ba++ produced by H Lyman alpha ionization, and Ca+, an impurity in the barium were detected in the cloud. A peak barium ion concentration of about 6,000,000 ions cu cm was measured at 161 km where the ionospheric NO+ and O2+ ions were essentially eliminated by large recombination loss. The bottom side of the barium cloud had a relatively smooth structure while the top side showed significant density fluctuations. The first experimental evidence of a theoretically predicted E region 'image cloud' was found in the form of an enhanced NO+ layer just below the barium cloud. Unexplained wave-like density variations in O+, NO+, and O2(+) also were seen above the barium cloud to 195 km. A quantitative estimate of the outgassing water vapor concentrations near the payload's surface was made using the fast change transfer rate coefficient for O+ + H2O yields H2O+ + O that created the observed water vapor ions.

Narcisi, R.; Tracinski, E.; Federico, G.; Wlodyka, L.; Bench, P.

1981-12-01

227

A study of positional disorder in strontium barium niobate  

Microsoft Academic Search

The first systematic examination of trends in the site occupancies of strontium and barium ions in strontium barium niobate (SBN) at three compositions across the phase range is presented. X-ray powder diffraction and Rietveld structure refinement were used to obtain refined structures for SBN. Some problems were encountered in the structure refinement due to the domain structure in the material.

M. P. Trubelja; E. Ryba; D. K. Smith

1996-01-01

228

Acute barium intoxication following ingestion of ceramic glaze.  

PubMed Central

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

Thomas, M.; Bowie, D.; Walker, R.

1998-01-01

229

SEPARATION OF RADIUM AND BARIUM BY ION EXCHANGE ELUTION  

Microsoft Academic Search

Radium can be separated from barium-radium mixtures in ratios as high as ; 4440to 1 by a single elution from a cation exchange resin. Bariuim elution ; characteristics from Dowex 50 resin, position of elution maxima, and maximum ; barium loadings are correlated with citrate concentration and pH by the use of ; citrate complex equilibria, Ammonium citrate, 0.32M at

W. H. Power; H. W. Kirby; W. C. McCluggage; G. D. Nelson; J. H. Jr. Payne

1959-01-01

230

Barium in Teeth as Indicator of Body Burden.  

National Technical Information Service (NTIS)

A study was conducted to determine the biological availability of naturally occurring barium in a municipal drinking water by the analysis of barium in deciduous teeth of children. The grade school children of two Illinois towns were chosen for the study....

R. G. Miller J. D. B. Featherstone M. E. J. Curzon T. S. Mills C. P. Shields

1985-01-01

231

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

232

Barium silicate films for integrated optical circuits.  

PubMed

This paper describes the preparation and properties of rf sputtered barium silicate films that are suitable for use as transmission media in integrated optical circuits. It is shown that the films, which can be produced with a wide range of refractive indices by suitable selection of the ratio of the target constituents, exhibit low optical attenuation. The techniques used to deposit the films and the effect on loss of a number of parameters including pressure, film thickness, and substrate bias are discussed. PMID:20125380

Goell, J E

1973-04-01

233

Scattering lengths of calcium and barium isotopes  

SciTech Connect

We have calculated the s-wave scattering length of all the even isotopes of calcium (Ca) and barium (Ba) in order to investigate the prospect of Bose-Einstein condensation (BEC). For Ca we have used an accurate molecular potential based on detailed spectroscopic data. Our calculations show that Ca does not provide other isotopes alternative to the recently Bose condensed {sup 40}Ca that suffers strong losses because of a very large scattering length. For Ba we show by using a model potential that the even isotopes cover a broad range of scattering lengths, opening the possibility of BEC for at least one of the isotopes.

Dammalapati, U.; Willmann, L.; Knoop, S. [Kernfysisch Versneller Instituut (KVI), University of Groningen, Zernikelaan 25, 9747 AA Groningen (Netherlands); LaserLaB Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam (Netherlands)

2011-11-15

234

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

235

How to Perform and Interpret Timed Barium Esophagogram  

PubMed Central

Timed barium esophagogram (TBE) is a simple and objective method for assessing the esophageal emptying. The technique of TBE is similar to usual barium swallow with some modifications, which include taking multiple sequential films at pre-decided time interval after a single swallow of a fixed volume of a specific density barium solution. While many authors have used height and width of the barium column to assess the esophageal emptying, others have used the area of the barium column. TBE is being used in patients with suspected or confirmed achalasia and to follow-up those who have been treated with pneumatic dilation or myotomy. This review discusses technique of performing TBE, interpretation and its utility in clinical practice.

Gupta, Mahesh; Ghoshal, Uday C

2013-01-01

236

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

237

Removal of sulfate from high-strength wastewater by crystallisation.  

PubMed

Sulfate causes considerable problems in anaerobic digesters, related to generation of sulfides, loss of electrons (and hence methane), and contamination of gas streams. Removal of sulfides is generally expensive, and still results in methane losses. In this paper, we evaluate the use of precipitation for low-cost sulfate removal, in highly contaminated streams (>1 gS L(-1)). The main precipitate assessed is calcium sulfate (gypsum), though the formation of complex precipitates such as jarosite and ettringite to remove residual sulfate is also evaluated. The four main concerns in contaminated wastewater are:- high solubility, caused by high ion activity and ion pairing; slow kinetics; inhibition of nucleation; and poisoning of crystals by impurities, rendering product unsuitable for reuse as seed. These concerns were addressed through batch experiments on a landfill wastewater with a similar composition to other sulfate rich industrial wastewaters (high levels of organic and inorganic contaminants). Crystallisation rates were rapid and comparable to what is observed by others for pure solutions (2-5 h). The kinetics of crystallisation showed a 2nd order dependence on supersaturation, which have implications for crystalliser design, as discussed in the paper. No spontaneous nucleation was observed (seed was required). Seed poisoning did not occur, and product crystals were as effective as pure seed. Solubility was increased by an order of magnitude compared to a pure solution (2.6x10(-3) M2 vs. 0.22x10(-3) M2). As evaluated using equilibrium modelling, this was caused equally by non-specific ion activity, and specific ion pairing. Jarosite and ettringite could not be formed at reasonable pH and temperature levels. Given the lack of complex precipitates, and relatively high solubility, gypsum crystallisation cannot practically be used to remove sulfate to very low levels, and gas-sulfide treatment will likely still be required. It can however, be used for low-cost bulk removal of sulfate. PMID:19059623

Tait, Stephan; Clarke, William P; Keller, Jurg; Batstone, Damien J

2008-11-21

238

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

239

Trends in pH, calcium, and sulfate of rivers in Atlantic Canada  

SciTech Connect

Acid precipitation is affecting the chemistry of rivers in Atlantic Canada. Long term records for pH, calcium, and sulfate from 11 rivers were fitted using time series models. Decreases in pH over time were found, but the results for calcium and sulfate were not consistent with the predicted model. The conceptual models used to understand the effects of acid precipitation on water chemistry did not adequately explain the observed changes.

Clair, T.A. (Environment Canada, Moncton, New Brunswick); Whitfield, P.H.

1983-01-01

240

In situ immobilization of heavy metals associated with uranium leach mines by bacterial sulfate reduction  

Microsoft Academic Search

Laboratory experiments with mixed populations of sulfate-reducing bactreria were shown to mediate the removal of milligrams\\/liter concentrations of uranium, selenium, arsenic and vanadium from aqueous solution via reduction, precipitation and adsorption. Results of laboratory experiments with active sulfidogenic biomass suggest that injection of sulfate and a source of carbon could enhance anaerobic microbial activity in and around uranium leach mines

John L. Uhrie; James I. Drever; Patricia J. S. Colberg; Carl C. Nesbitt

1996-01-01

241

Distinguishing solid bitumens formed by thermochemical sulfate reduction and thermal chemical alteration  

Microsoft Academic Search

Insoluble solid bitumens are organic residues that can form by the thermal chemical alteration (TCA) or thermochemical sulfate reduction (TSR) of migrated petroleum. TCA may actually encompass several low temperature processes, such as biodegradation and asphaltene precipitation, followed by thermal alteration. TSR is an abiotic redox reaction where petroleum is oxidized by sulfate. It is difficult to distinguish solid bitumens

Simon R. Kelemen; Clifford C. Walters; Peter J. Kwiatek; Mobae Afeworki; Michael Sansone; Howard Freund; Robert J. Pottorf; Hans G. Machel; Tongwei Zhang; Geoffrey S. Ellis; Yongchun Tang; Kenneth E. Peters

2008-01-01

242

Microbial sulfate reduction and its potential utility as an acid mine water pollution abatement procedure  

Microsoft Academic Search

The presence of high concentrations of sulfate, iron, and hydrogen (acid) ions in drainage from coal mines and other areas containing waste pyritic materials is a serious water pollution problem. Sulfate can be removed from solution by microbial reduction to sulfide and subsequent precipitation as FeS. A mixed culture of microorganisms degraded wood dust cellulose, and the degradation products served

J. H. Tuttle; P. R. Dugan; C. I. Randles

1969-01-01

243

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

2012-06-06

244

Iron Reduction and Carbonate Precipitation by Shewanella oneidensis  

NASA Astrophysics Data System (ADS)

This study is to contribute to better understanding of how Archean microbes induced carbonate diagenesis in mats and stromatolites. Previous studies showed sulfate reduction, a common promoter of carbonate precipitation in modern mats[1], is likely to have been less effective in Archean mats in marine fluids lower in sulfate[2]. Alternatively, iron reduction produces far more alkalinity per unit carbon respired than sulfate reduction. Therefore, we hypothesize iron reduction can promote much more carbonate precipitation than sulfate reduction. Our study might also have some relevance to banded iron formation on which microbial iron reduction played a potential role[3]. To test our hypothesis, Shewanella oneidensis MR-1, a dissimilatory iron reducing bacterium will be cultured anaerobically (79%N2, 20%CO2 and 1%H2) in basal medium to trigger iron reduction. Lactate will be used as electron donor, and the electron acceptor will be fresh ferrihydrite. Culture medium will be added with various metal ions, such as Ca2+ and Mg2+, to obtain potential carbonate precipitate. Escherichia coli (with fumarate added as an electron acceptor) will be used to provide a comparison to live but non-iron- reduction cells. After 20 days incubation, precipitate will be collected, washed and identified by X-ray diffraction (XRD). Besides, iron reduction rate (ferrozine assay)[4], PH and amount of precipitate (carbonate and oxidize fractions)[5] will be measured over time to well understand how S. oneidensis drives carbonate precipitation.

Zeng, Z.; Tice, M. M.

2011-12-01

245

Proton conductivity of potassium doped barium zirconates  

SciTech Connect

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

Xu Xiaoxiang [School of Chemistry, University of St. Andrews, Fife KY16 9ST (United Kingdom); Tao Shanwen, E-mail: s.tao@hw.ac.u [School of Chemistry, University of St. Andrews, Fife KY16 9ST (United Kingdom); Department of Chemistry, Heriot-Watt University, Edinburgh EH14 4AS (United Kingdom); Irvine, John T.S. [School of Chemistry, University of St. Andrews, Fife KY16 9ST (United Kingdom)

2010-01-15

246

Precipitation chemistry in central Amazonia  

NASA Astrophysics Data System (ADS)

Rain samples from three sites in central Amazonia were collected over a period of 6 weeks during the 1987 wet season and analyzed for ionic species and dissolved organic carbon. A continuous record of precipitation chemistry and amount was obtained at two of these sites, which were free from local or regional pollution, for a time period of over 1 month. The volume-weighted mean concentrations of most species were found to be about a factor of 5 lower during the wet season compared with previous results from the dry season. Only sodium, potassium, and chloride showed similar concentrations in both seasons. When the seasonal difference in rainfall amount is taken into consideration, the deposition fluxes are only slightly lower for most species during the wet season than during the dry season, again with the exception of chloride, potassium, and sodium. Sodium and chloride are present in the same ratio as in sea salt; rapid advection of air masses of marine origin to the central Amazon Basin during the wet season may be responsible for the observed higher deposition flux of these species. Statistical analysis suggests that sulfate is, to a large extent, of marine (sea salt and biogenic) origin, but that long-range transport of combustion-derived aerosols also makes a significant contribution to sulfate and nitrate levels in Amazonian rain. Organic acid concentrations in rain were responsible for a large fraction of the observed precipitation acidity; their concentration was strongly influenced by gas/liquid interactions.

Andreae, M. O.; Talbot, R. W.; Berresheim, H.; Beecher, K. M.

1990-09-01

247

Spontaneous Oxidation of Barium Tin(II) Chloride Fluorides  

NASA Astrophysics Data System (ADS)

Covalently bonded BaSnF4, BaSn2F6 and new barium tin(II) chloride fluorides BaSn2Cl2F4, BaSnClF3.0.8H2O, and non-stoichiometric Ba1-xSnxCl1+yF1-y were prepared and their stability upon long time storage in air was studied, with respect to tin(II) oxidation to tin(IV). The materials containing covalently bonded tin(II), i.e., all the stoichiometric phases, were found to passivate well due to particle coverage by a thin layer of SnO2 and/or kinetic stabilization of hybridized tin(II), and they show a very minimal increase of tin(IV) signal with increasing storage time. At high temperature, passivation breaks down, then self restores. In contrast, the Ba1-xSnxCl1+yF1-y solid solution is not as well passivated. The rate of increase of tin(IV) Mössbauer signal is significantly higher for the precipitated solid solution, and was found to be inversely related to the amount of tin(IV) already present in the young sample. For the solid solution prepared in dry conditions, the ratio of tin oxidation was found to be higher at positive y values (Cl:F>1) and to decrease with increasing x (tin rich solid solution). In the solid solution, the bond type and strength vary widely with x and y, and so does the rate of oxidation. ``Unprotected'' Sn2+, weakly bound to the lattice, oxidizes much faster than covalently bonded tin(II).

Dénès, Georges; Muntasar, Abdualhafed

248

Remediation of Acid Mine Drainage with Sulfate Reducing Bacteria  

ERIC Educational Resources Information Center

|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…

Hauri, James F.; Schaider, Laurel A.

2009-01-01

249

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

250

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 120 h and at 150 °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.

2006-08-01

251

A high-altitude barium radial injection experiment  

NASA Astrophysics Data System (ADS)

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.

1980-12-01

252

Synthesis and characterization of barium hexagonal ferrite  

NASA Astrophysics Data System (ADS)

Barium Hexagonal ferrite (BaFe12O19) was synthesized by a two step process, first by high-energy ball milling and then sintering the milled powder subsequently at 950°C. The phase formation and morphology studies were carried out using X-ray Diffraction (XRD) and High Resolution Scanning Electron Microscopy (HRSEM) respectively. XRD results clearly show the phase purity and the good crystalline nature of BaFe12O19. The mean particle size was found to be 80 nm from the SEM image. The magnetic properties such as saturation magnetization and coercive field were calculated from the magnetization curve, which was obtained using Vibrating Sample Magnetometer (VSM). A possible relation between the magnetic hysteresis curve and the microstructure of the sintered sample has been investigated.

Manikandan, M.; Venkateswaran, C.

2013-02-01

253

PRECIPITATION METHOD OF SEPARATION OF NEPTUNIUM  

DOEpatents

A process is described for the separation of neptunium from plutonium in an aqueous solution containing neptunium ions in a valence state not greater than +4, plutonium ioms in a valence state not greater than +4, and sulfate ions. The Process consists of adding hypochlorite ions to said solution in order to preferentially oxidize the neptunium and then adding lanthanum ions and fluoride ions to form a precipitate of LaF/sub 3/ carrying the plutonium, and thereafter separating the supernatant solution from the precipitate.

Magnusson, L.B.

1958-07-01

254

Physico-chemical transformations of sulfated compounds during the leaching of highly sulfated cemented wastes  

SciTech Connect

Cementation of sulfated evaporator concentrates leads to highly sulfated low level wastes, (ca. 25% w/w sodium sulfate solution as mix water), which exhibit the presence of U-phase, a sodium-bearing calcium monosulfphoaluminate-like phase. During the leaching of simulated highly sulfated OPC/BFS cements, cured at room temperature and containing U-phase, sodium sulfate, and ettringite, physico-chemical transformations have been pointed out (transformation of U-phase into ettringite). Samples having the same chemical composition, but cured at high temperature (maximal temperature during curing: 120 C), do not contain ettringite initially, but secondary ettringite is formed during leaching. XRD spectra point out the existence of precipitation fronts (or of phase formation fronts) varying linearly versus the square root of time. The analysis of leaching solutions has provided complementary data used in a code, the aim of which is to assess cement degradation, based on coupling between transport by diffusion and chemical reactions (DIFFUZON code). The U-phase-ettringite transformation is confirmed.

Lovera, P.; Bescop, P. le; Adenot, F. [CEA Centre de`Etudes de Saclay, Gif/Yvette (France); Li, G. [CEA Centre d`Etudes de Saclay, Gif/Yvette (France)]|[Ecole Normale Superieure de Cachan (France). Lab. de Mecanique et de Technologie; Tanaka, Y. [Japan Nuclear Fuel Ltd., Tokyo (Japan); Owaki, E. [Taisei Corp., Yokohama (Japan). Technology Research Center

1997-10-01

255

Glycopeptide Sulfation Evades Resistance  

PubMed Central

The incidence of antibiotic resistance among pathogenic microorganisms is increasing at an alarming rate. Resistance against front-line therapeutics such as the glycopeptide antibiotic vancomycin has emerged and has spread to highly virulent pathogens, including Staphylococcus aureus. Glycopeptide antibiotics are natural products from the Actinomycetes that have a characteristic heptapeptide core. The chemical diversity of the class is achieved through glycosylation, halogenation, methylation, and acylation of the core, modifications that are implicated in improved solubility, stability, or activity of the molecule. Sulfation is yet another modification observed infrequently in glycopeptides, but its role is not known. Although glycopeptide sulfotransferases are found in the environmental metagenome and must therefore serve an evolutionary purpose, all previous studies have reported decreased antibiotic activity with sulfation. We report that sulfation of glycopeptides has little effect on the compound's ability to bind its target, the d-Ala-d-Ala peptidoglycan precursors of the bacterial cell wall. However, sulfation does impact glycopeptide dimerization, and importantly, sulfated glycopeptides are significantly less potent inducers of the resistance gene cluster vanHAX in actinomycetes. Our results begin to unravel the mystery of the biological role of glycopeptide sulfation and offer a potential new strategy for the development of new antibiotics that avoid resistance.

Kalan, Lindsay; Perry, Julie; Koteva, Kalinka; Thaker, Maulik

2013-01-01

256

Microscopic Theory of the Phonon Frequencies in bcc Barium.  

National Technical Information Service (NTIS)

The phonon dispersion frequencies are calculated from first principles for bbc barium using a resonance pseudopotential model which incorporates the effect of s-d hybridization. It was also possible using this scheme to account for the anomalous feature o...

B. A. Oli

1988-01-01

257

Calculated emission rates for barium releases in space  

NASA Astrophysics Data System (ADS)

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.

1989-11-01

258

A systematic morphosynthesis of barium sulfate in the presence of phosphonate inhibitor.  

PubMed

A systematic study of the influence of various experimental parameters on the morphology and size of BaSO4 crystals after crystallization from water in the presence of diethylenetriamine penta (methylphosphonic acid) (DETPMP) was presented. Depending on the experimental conditions, there are various crystal morphologies including flowers, ellipsoids, spheres, or conjoined spheres. The results indicated that the experimental parameters, such as the concentration of the inhibitor, the pH of solution, the aging of the particle growth, and the ratio [Ba2+]/[SO4(2-)], are important for the morphology and size of BaSO4. The morphogenesis of BaSO4 is controlled by the chelation of DETPMP with Ba2+ at the nucleation and the surface adsorption inhibition of crystal growth. PMID:16054640

Wang, Fang; Xu, Guiying; Zhang, Zhiqing; Song, Shue; Dong, Shuli

2005-07-28

259

Composition and structure measurements in an ionospheric barium cloud  

Microsoft Academic Search

A 48 kg barium payload was launched from Eglin Air Force Base, Florida on 12 December 1980 at 2311 GMT and detonated at 183.7 km. At 2342:50.25 GMT, a second rocket, instrumented with an ion mass spectrometer and pulsed plasma probes, was fired to traverse the barium cloud. Composition, ion density, and structure measurements were acquired up to 241.2 km

R. Narcisi; E. Tracinski; G. Federico; L. Wlodyka; P. Bench

1981-01-01

260

The problem of heavy-element synthesis in barium stars  

NASA Astrophysics Data System (ADS)

An abundance analysis of the atmospheres of 33 stars, barium and normal G-K giants, is carried out using the differential model atmosphere method. Twenty barium stars which reveal a considerable enhancement of s-process elements exhibit slight depletions (about 0.2 dex) of Na, Mg, Mn, and Co; solar abundances for Si to Ni; and enhanced abundances (up to 1.5 dex) for Y to Eu. Mean parameters of the atmospheres are determined.

Zacs, L.

1991-07-01

261

Investigations on surface composition and microstructure of sintered barium titanate  

Microsoft Academic Search

The paper describes studies on surface atomic composition, microstructure and microarea elemental distribution in sintered\\u000a undoped as well as donor or acceptor doped polycrystalline barium titanate ceramics. The specimens examined are derived from\\u000a barium titanate powders synthesized by two different wet chemical procedures namely oxalate precursor route and gel-to-crystallite\\u000a conversion. The compositional analysis is carried out by backscattering spectrometry (BS)

Sanjiv Kumar; V. S. Raju; T. R. N. Kutty

2007-01-01

262

Catalytic combustion of methane on substituted barium hexaaluminates  

Microsoft Academic Search

A sol–gel method using metallic barium, aluminum alkoxides and metal nitrates has been used to synthesize barium hexaaluminate partially substituted by either manganese, iron or both metal ions. The ?-alumina structure was obtained by calcination under oxygen at 1200°C. X-ray analysis revealed that formation of a pure single phase BaMxAl12?xO19 occurred up to x=4 for Fe, x=3 for Mn and

P Artizzu-Duart; J. M Millet; N Guilhaume; E Garbowski; M Primet

2000-01-01

263

Synthesis of nanocomposites comprising iron and barium hexaferrites  

Microsoft Academic Search

Composites of nanometre-sized ?-iron and barium hexaferrite phases, respectively, have been synthesized by the ceramic processing route. Pure barium hexaferrite (BaO·6Fe2O3) was first of all prepared by calcinations of the precursor oxides at a maximum temperature of 1200°C for 4h. By subjecting the resulting powder having particle size of the order of 1?m to a reduction treatment in the temperature

M. Pal; S. Bid; S. K Pradhan; B. K Nath; D. Das; D. Chakravorty

2004-01-01

264

Use of Oxygen Isotopy in the Study of SO sub 2 to Sulfates in the Atmosphere.  

National Technical Information Service (NTIS)

Previous experimental results have indicated that the exp 18 O/ exp 16 O ratios in water vapor, precipitation water, and sulfate contained in precipitation water vary seasonally (higher in summer, lower in winter), while the exp 18 0/ exp 16 0 ratio in at...

B. D. Holt P. T. Cunningham R. Kumar

1979-01-01

265

Sulfation in dog.  

PubMed

Sulfation has been thoroughly studied in several species including e.g. man and rat. However, one important species often used for pharmacological drug studies is the dog. Here we describe recent advances as well as older data in the field of dog sulfation. Species differences in sulfation have been reported. Stereoselectivity, inhibition by pentachlorophenol, bioactivation of DNA binding species, and gender differences have also been observed for canine sulfotransferases (SULTs). Several drugs are being sulfated in vivo in dog, e.g. xamoterol, 4'-hydroxypropanolol, paracetamol and salicylamide. However, studies have shown that also e.g. canine hepatocytes and liverslices will sulfate substrates e.g. paracetamol and 7-hydroxycoumarin in in vitro experiments. Recently, three different enzymes have been cloned and characterized from canine liver, cSULT1A1, cSULT1B1 and cSULT1D1. cSULT1A1 being very similar to the human ortholog in terms of substrate specificity and is also ubiquitously expressed in canine tissues. The cSULT1B1 enzyme is also very similar in both distribution pattern as well as substrate preference compared to the human ortholog. The third enzyme, cSULT1D1, sulfates dopamine with high efficiency and it has no counterpart in man since it is found as a pseudogene. The importance of amino acid residue 247 in cSULT1D1 will be discussed since it can alter the ratio of sulfation of dopamine versus para-nitrophenol. In addition, the phenomenon of the high expression of the canine enzymes in colon is discussed. PMID:15975044

Tsoi, C; Swedmark, S

2005-06-01

266

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

PubMed

Calcium-barium phosphate (CBP) composite membrane with 25% polystyrene was prepared by co-precipitation method. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transformed infrared (FTIR), and Thermogravimetric analysis (TGA) were used to characterize the membrane. The membrane was found to be crystalline in nature with consistent arrangement of particles and no indication of visible cracks. The electrical potentials measured across the composite membrane in contact with univalent electrolytes (KCl, NaCl and LiCl), have been found to increase with decrease in concentrations. Thus the membrane was found to be cation-selective. Transport properties of developed membranes may be utilized for the efficient desalination of saline water and more importantly demineralization process. The antibacterial study of this composite membrane shows good results for killing the disease causing bacteria along with waste water treatment. PMID:23910337

Khan, Mohammad Mujahid Ali; Rafiuddin

2013-06-21

267

Gastrointestinal tract labeling for MDCT of abdomen: Comparison of low density barium and low density barium in combination with water  

Microsoft Academic Search

The purpose of the study was to compare the quality of stomach and small bowel marking\\/labeling using 1,350 ml of low-density\\u000a barium alone (VoLumen) with 900 ml of low-density barium and 450 ml of water for 16-MDCT scans of the abdomen and pelvis and\\u000a assess cost benefits with the two protocols. In this IRB approved study, 80 consecutive patients scheduled for routine CECT

Kavita Gulati; Zarine K. Shah; Nisha Sainani; Raul Uppot; Dushyant V. Sahani

2008-01-01

268

Determination of Cremophor® EL in plasma after sample preparation with solid phase extraction and plasma protein precipitation  

Microsoft Academic Search

The non-ionic emulsifier Cremophor® EL can be quantified using a special potentiometric titration technique with barium chloride activation and precipitation with sodium tetraphenylborate. The end point of the titration is indicated by an ionsensitive coated wire electrode which responds to an excess of tetraphenylborate ions. Sample preparation is necessary to quantify the excipient in plasma of patients receiving ciclosporin formulations

Th Meyer; J Böhler; A. W Frahm

2001-01-01

269

Measurements of the artificially stimulated precipitation of electrons from the inner radiation belt in the experiment 'Spolokh-2'  

NASA Astrophysics Data System (ADS)

Artificial ionospheric disturbances, resulting from a barium shaped charge release from Spolokh-2 rocket payload, launched on June 29, 1978, are described. Geiger counters were used to detect the stimulated fluxes of the precipitated electrons with energies greater than 40 keV. The spectral analysis of the counter data was used to find the short- and long-term charges of the electron fluxes after the charge explosion. Artificial precipitation of electrons was observed more than 100 s after the explosion.

Zhulin, I. A.; Kostin, V. M.; Pimenov, I. A.; Ruzhin, Iu. Ia.; Skomarovskii, V. S.; Zhuchenko, Iu. M.; Romanovskii, Iu. A.

270

Influence of Operating Conditions on BaSO4 Crystal Size and Morphology in a Continuous Couette Precipitator  

Microsoft Academic Search

Precipitation of a sparingly soluble salt in the annular gap of a continuous Couette reactor with two unpremixed feeds has\\u000a been experimentally investigated. Barium chloride and sodium sulphate in stoichiometric ratio are fed at different flow rate\\u000a in the lower part of the reactor; different feeding modes have been considered. The dependence of precipitation yield, mean\\u000a crystal size and particle

S. Pagliolico; D. Marchisio; A. A. Barresi

1999-01-01

271

Crystallization of calcium sulfate dihydrate and calcium sulfite hemihydrate from synthetic flue gas desulfurization solutions: Final report  

SciTech Connect

The precipitation of calcium sulfate dihydrate (CaSO/sub 4/.2H/sub 2/O) and calcium sulfite hemihydrate (CaSO/sub 3/.1/2H/sub 2/O) from high, up to 240,000 mg/L, total dissolved solids (TDS) solutions was studied at 50/sup 0/C. The solutions were selected to cover a range of solution compositions of magnesium, calcium, sodium, chloride, and sulfate. Precipitation rates along with crystal habit and size changes were measured to determine the effects of these dissolved species as compared to dilute solution conditions. Calcium sulfate dihydrate (gypsum) precipitation rate was accelerated in the high TDS solutions, especially those containing chloride ion. Alternatively, calcium sulfite hemihydrate precipitation rate was found to be faster in high sulfate ion containing solutions. Sodium ion appears to produce gypsum crystals more columnar in habit while solutions containing high amounts of calcium produced very lamellar gypsum crystals. Solutions containing magnesium produced acicular gypsum crystals. Calcium sulfite hemihydrate solids precipitated from solutions containing high sulfate concentrations were rod shaped and globular as compared to the lamellar calcium sulfite hemihydrate crystals precipitated from high chloride and dilute solution liquors. Calcium sulfate-calcium sulfite solid solutions were characterized using infrared spectroscopy. Ion scavenging of Na, Mg, and Cl by gypsum and calcium sulfite solids precipitated from these high TDS solutions was also investigated. 10 refs., 21 figs., 13 tabs.

Trofe, T.W.; Fishman, V.A.; Meserole, F.B.

1986-10-01

272

The Effect of Iron and Sulfate Levels on the Transition from Iron to Sulfate Reduction during Biostimulation  

NASA Astrophysics Data System (ADS)

During biostimulation of microbial iron reduction for the purpose of U(VI) removal at the Rifle Integrated Field Challenge (IFC) site, the onset of sulfate reduction is usually observed within 20 to 30 days of biostimulation. A series of flow-through sediment column experiments were performed to determine if the onset of sulfate reducing conditions occurs while bioavailable Fe(III) is still present, if it the onset of sulfate reduction can be delayed by increasing the amount of bioavailable Fe(III), and to determine how the bioreduction of uranium is affected by the switch from iron-dominated to sulfate-dominated reducing conditions. The experiment also focused on the changes in the microbial population and how it is affected by varying the iron content in the sediment. For this purpose a set of column experiments was conducted using Rifle site sediments and two levels of sulfate in the inflow, while a second set of experiments was conducted with Rifle sediments augmented with small amounts of Fe-57 goethite. Fe-57 goethite was used in this experiment to track minute Fe(III) changes in augmented goethite via Mössbauer spectroscopy before and after the onset of sulfate reduction. Columns were sacrificed at regular intervals to determine extractable Fe(II) and Fe(III), precipitated U(IV), and analyze for the changes in biomass composition. The results showed that under low sulfate levels, iron reduction could be maintained for over two-hundred days, while in the presence of high sulfate levels, sulfate reduction was observed within thirty days, indicating that during biostimulation sulfate reduction can commence even though a significant pool of bioavailable Fe(III) is still present. The rate of U(VI) reduction was not negatively affected by the commencement of sulfate reducing conditions, an observation that differs from field results where U(VI) reduction has been observed to decrease after the onset of sulfate reduction. The addition of goethite to the sediments did not affect the time for the onset of sulfate reduction but appears to slightly suppress the amount of sulfate reduced. The sediment-attached microbial population is dominated by 6 TRFLP peaks. Three of these peaks have been identified, a Desulfovibrio-like clone, a Rhodoferax-like clone, and a Geobacter-like clone, totaling 14.5%, 26%, and 3.1% of the overall community profile, respectively. Addition of the goethite to the sediment had a noticeable effect on the overall composition of the microbial population.

Jaffe, P. R.; Kerkhoff, L.; Komlos, J.; Kukkadapu, R. K.; Long, P. E.; McGuinness, L.; Moon, H. S.

2008-12-01

273

Barium studies for detecting esophagopharyngeal reflux events.  

PubMed

Esophagopharyngeal reflux (EPR) is among the factors involved in the supraesophageal complications of reflux disease, and is diagnosed by the regurgitation of barium from the upper third of the esophagus into the pharynx in the absence of swallow during a videofluoroscopic swallowing study. EPR is detected in approximately 20% of patients undergoing these studies, and occurs in different clinical groups without disease-specific associations. The vast majority of patients with EPR show esophageal motor abnormalities on swallowing studies. Notably, prolonged esophageal clearing time is independently and strongly associated with EPR. Our data suggest that the oropharyngeal phase of deglutition is impaired in >50% of patients with both gastroesophageal reflux disease and EPR. In the subset of patients with EPR, oral abnormalities are mostly related to tongue function. Based on the data emerging from our videofluoroscopic swallowing studies, it seems plausible that EPR occurs as a result of an underlying esophageal motor dysfunction facilitated by an impaired oral deglutition. As a consequence, when examining patients for EPR, both esophageal and oropharyngeal abnormalities should be sought. PMID:12928088

Torrico, Silvia; Corazziari, Enrico; Habib, Fortunée Irene

2003-08-18

274

PRECIPITATION OF PLUTONOUS PEROXIDE  

DOEpatents

A precipitation process for recovering plutonium values contained in an aqueous solution is described. In the process for precipitating plutonium as plutonous peroxide, hydroxylamine or hydrazine is added to the plutoniumcontaining solution prior to the addition of peroxide to precipitate plutonium. The addition of hydroxylamine or hydrazine increases the amount of plutonium precipitated as plutonous peroxide. (AEC)

Barrick, J.G.; Manion, J.P.

1961-08-15

275

PRECIPITATION OF PLUTONOUS PEROXIDE  

Microsoft Academic Search

A precipitation process for recovering plutonium values contained in an ; aqueous solution is described. In the process for precipitating plutonium as ; plutonous peroxide, hydroxylamine or hydrazine is added to the ; plutoniumcontaining solution prior to the addition of peroxide to precipitate ; plutonium. The addition of hydroxylamine or hydrazine increases the amount of ; plutonium precipitated as plutonous

J. G. Barrick; J. P. Manion

1961-01-01

276

ELECTRODE POTENTIALS IN MOLTEN LITHIUM SULFATE-POTASSIUM SULFATE EUTECTIC  

Microsoft Academic Search

The lithium sulfate --potassium sulfate eutectic (80% lithium sulfate by ; mole; melting point 535 deg ) was shown to be an adequate molten solvent for ; electrochemical investigations at 625 deg . A procedure for preparing the ; eutectic melt was established. The silver(I) --silver(0) system was found to be ; a satisfactory reference electrode in this melt. The

C. H. Liu

1962-01-01

277

Crystallization of CaCO3 in the presence of sulfate and additives: experimental and molecular dynamics simulation studies.  

PubMed

The effects of sulfate and BHTPMP (Bis (hexamethylene) triaminepentakis (methylene phosphonic acid)) on the crystallization rate, phase composition and morphology of calcium carbonate have been studied. It was observed that sulfate reduces the nucleation rate and favors the formation of aragonite form in the calcium carbonate precipitate. Moreover, in the presence of sulfate the rhombohedral morphology of the calcite crystals is modified, and during the formation of calcite, the development of {104} faces are more significantly prohibited than {110} faces. In the presence of sulfate together with BHTPMP, the crystallization process is inhibited and the modified morphology and the dominant calcite form are observed in the solid. The results from molecular dynamics simulations show the more strong combination of sulfate with calcite surface, in particular the {104} face, in comparison with the aragonite surface. The strong interaction of BHTPMP with sulfate and the aragonite surface favors the formation of the dominant calcite phase in the precipitate. PMID:22487230

Tang, Yongming; Zhang, Fan; Cao, Ziyi; Jing, Wenheng; Chen, Yizhong

2012-03-23

278

Stratospheric Sulfate Aerosol  

Microsoft Academic Search

The purpose of this research is to explore the spatial and temporal variability of the stratospheric sulfate layer, its chemical composition, and mode of formation. In addition, trace chemical concentrations in the natural stratosphere are provided as reference values before extensive use of the stratosphere for aircraft travel. EXPERIMENTAL This research comprises a systematic study of the stable constituents of

A. L. Lazrus; B. W. Gandrud

1974-01-01

279

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

280

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

281

21 CFR 524.960 - Flumethasone, neomycin sulfate, and polymyxin B sulfate ophthalmic solutions.  

Code of Federal Regulations, 2010 CFR

...Flumethasone, neomycin sulfate, and polymyxin B sulfate ophthalmic solutions...Flumethasone, neomycin sulfate, and polymyxin B sulfate ophthalmic solutions...base), and 10,000 units of polymyxin B sulfate, with or without...

2009-04-01

282

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

Code of Federal Regulations, 2010 CFR

... false Neomycin sulfate and polymyxin B sulfate ophthalmic solution...1484e Neomycin sulfate and polymyxin B sulfate ophthalmic solution...base), and 10,000 Units of polymyxin B sulfate. (b) Sponsor....

2009-04-01

283

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

Code of Federal Regulations, 2010 CFR

... false Neomycin sulfate and polymyxin B sulfate ophthalmic solution...1484e Neomycin sulfate and polymyxin B sulfate ophthalmic solution...base), and 10,000 Units of polymyxin B sulfate. (b) Sponsor....

2010-04-01

284

21 CFR 524.960 - Flumethasone, neomycin sulfate, and polymyxin B sulfate ophthalmic solutions.  

Code of Federal Regulations, 2010 CFR

...Flumethasone, neomycin sulfate, and polymyxin B sulfate ophthalmic solutions...Flumethasone, neomycin sulfate, and polymyxin B sulfate ophthalmic solutions...base), and 10,000 units of polymyxin B sulfate, with or without...

2010-04-01

285

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

286

Acceleration of barium ions near 8000 km above an aurora  

NASA Astrophysics Data System (ADS)

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.

1984-12-01

287

Crystallization of calcium sulfate dihydrate and calcium sulfite hemihydrate from synthetic flue gas desulfurization solutions: Final report  

Microsoft Academic Search

The precipitation of calcium sulfate dihydrate (CaSOâ.2HâO) and calcium sulfite hemihydrate (CaSOâ.1\\/2HâO) from high, up to 240,000 mg\\/L, total dissolved solids (TDS) solutions was studied at 50°C. The solutions were selected to cover a range of solution compositions of magnesium, calcium, sodium, chloride, and sulfate. Precipitation rates along with crystal habit and size changes were measured to determine the effects

T. W. Trofe; V. A. Fishman; F. B. Meserole

1986-01-01

288

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

289

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

PubMed

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 H2 35SO4) 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. PMID:3561145

Dallam, R D

1987-03-23

290

Relationship between microbial sulfate reduction rates and sulfur isotopic fractionation  

NASA Astrophysics Data System (ADS)

Sulfate reduction is one of the common processes to obtain energy for certain types of microorganisms.They use hydrogen gas or organic substrates as electron donor and sulfates as electron acceptor, and reduce sulfates to sulfides. Sulfate reducing microbes extend across domains Archea and Bacteria, and are believed to be one of the earliest forms of terrestrial life (Shen 2004). The origin of 34S-depleted (light) sulfide sulfur, especially ?34S < -30 ‰, around hydrothermal vents or beneath the sea-floor is speculated to be the products of sulfate reducers. But laboratory experiments using sulfate reducers fail to produce such light sulfur, and many models were proposed to explain the discrepancy. Canfield et al. (2006) proposed so-called "standard model" based on previous studies. The standard model explained the reason for the large fractionation by temperature dependence of sulfur isotopic fractionation factor and rate of sulfate reduction, which indicated the growth conditions of microbes. However, they failed to prove their model by their other experiments (Canfield et al., 2006). In this study, I performed laboratory culture experiment of sulfate reducing bacteria (SRB) to explain the 34S-depleted sulfide sulfur. [Experiments] To compare the result with Canfield et al. (2006), I used Desulfovibrio desulfuricans for my laboratory culture experiment. D. desulfuricans was inoculated into glass vials, which contain 40ml of liquid culture media slightly modified from DSMZ #63 medium.Excess amount of Fe (II) is added to the DSMZ#63 medium to precipitate sulfide as iron sulfide. The vials were incubated at 25°C, 30°C, and 37°C, respectively. 21 vials were used for one temperature and sulfide and sulfate was collected from each three glass vials at every 12 hours from 72 hours to 144 hours after start of incubation. The sulfide was precipitated as iron sulfide and the sulfate was precipitated as barite. Sulfur isotope compositions of sulfate and sulfide were measured by standard method using Delta Plus mass-spectrometer. [Results and Discussion] The fractionation between sulfide and sulfate ranged from 2.7 to 11.0. The fractionation values varied among the different incubation temperature and growth phase of D. desulfuricans. The maximum fractionation values of three incubation temperatures were 9.9, 11.0, and 9.7, for 25 °C, 30°C, and 37°C, respectively. These results were different from standard model and Canfield et al. (2006). I could not find the clear correlation between ?34S values and incubation temperatures in this experiment. The measured fractionation values during the incubation varied with incubation stage. The fractionation values clearly increased with incubation time at every temperature, and at 25°C ?34S value was 3.6 at the 72h and it increased to 7.9 at 144 hours. This indicated the difference of sulfate reduction rate due to the growth phase of SRB. In the early logarithmic growth phase, metabolic activity of SRB is high and sulfate reduction rate is fast. In contrast at the stationary phase, SRB stop growing and sulfate reduction rate get slower. My result suggested that the sulfur isotopic fractionation is controlled by growth phase of SRB and lighter sulfide would be produced by the stationary phase or half-dormant SRB in natural environment.

Matsu'Ura, F.

2009-12-01

291

Effects of Iron Sulfate Dosage on the Water Flea ( Daphnia magna Straus) and Early Development of Carp ( Cyprinus carpio L.)  

Microsoft Academic Search

Adult water fleas, Daphnia magna Straus, and the early life stages of carp, Cyprinus carpio L., were exposed to river water near an iron sulfate dosage installation to determine the effects of phosphate precipitation\\u000a with iron(II)sulfate. Tests were conducted during two consecutive dosage periods of 3,000 and 5,000 kg\\/day iron sulfate (520\\u000a and 620 ?g\\/L total Fe respectively) at the

F. A. T. Spanings; A. H. Knol; J. A. van der Velden; S. E. Wendelaar Bonga

2002-01-01

292

Degree of supersaturation and precipitation of organogenic dolomite  

SciTech Connect

This paper integrates the degree of carbonate saturation into a general model for the origin of dolomite in organic-rich marine sediments. Degradation of organic matter by sulfate-reducing bacteria promotes early dolomite precipitation by simultaneously increasing the carbonate alkalinity and lowering the sulfate ion concentration to near zero. The interstitial water in organic-rich sediments of several Deep Sea Drilling Project sites where dolomite is believed to be precipitating is up to 10/sup 3/ times supersaturated with respect to near-ideal dolomite and up to 10 times supersaturated with respect to calcite. The highly supersaturated interstitial waters appear to overcome low-temperature kinetic barriers to precipitate a nonideal, fine-grained calcian dolomite. The degree of supersaturation with respect to dolomite decreases, and the interstitial water approaches carbonate equilibrium with increasing burial depth at several of these sites. Removal of sulfate ion is important because sulfate ion may inhibit dolomite precipitation. A calcareous sediment is not required, but the presence of calcite or aragonite appears to greatly enhance dolomitization by providing an additional source of Ca and carbonate ions.

Compton, J.S.

1988-04-01

293

SPATIAL AND TEMPORAL PATTERNS OF ACID PRECIPITATION AND THEIR INTERPRETATION  

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. Geographic patterns of concentration and deposition are characterized using isopleth m...

294

METHOD OF IMPROVING THE CARRIER PRECIPITATION OF PLUTONIUM  

DOEpatents

Plutonium values can be recovered from acidic solutlons by adding lead nitrate, hydrogen fluoride, lantha num nitrate, and sulfurlc acid to the solution to form a carrler preclpitate. The lead sulfate formed improves the separatlon characteristics of the lanthanum fluoride carrier precipitate,

Kamack, H.J.; Balthis, J.H.

1958-12-01

295

Process of precipitating zirconium or hafnium from spent pickling solutions  

SciTech Connect

This patent describes a process for regenerating a spent, fluoride-containing pickle solution used in the pickling of zirconium or hafnium metal or their alloys. It comprises adding to the spent pickle solution a sufficient amount of sodium sulfate to precipitate sodium zirconium or hafnium fluoride.

Aguilar, C.L.; Walker, R.G.

1991-12-31

296

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

297

Barium-borate-flyash glasses: As radiation shielding materials  

NASA Astrophysics Data System (ADS)

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

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

2008-01-01

298

White dwarf kicks and implications for barium stars  

NASA Astrophysics Data System (ADS)

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

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

299

A high-altitude barium radial injection experiment  

NASA Astrophysics Data System (ADS)

On 16 March 1980 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 purpose of the experiment, named ``King Crab,'' was to advance knowledge of the instabilities, waves, and optical and magnetic effects produced. The TV images of the injection are spectacular, revealing three major regimes of expanding material 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 computer simulations show a similar rayed structure development due to an electrostatic instability.

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

300

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

301

The use of antispasmodic drugs during barium enemas.  

PubMed

In 1958, Welin recommended the routine use of atropine before a barium enema to reduce mucus secretion and make the examination more comfortable. Currently, many radiologists believe that smooth-muscle spasmolysis is a useful adjunct during a barium enema and use such a spasmolytic agent. One survey found that spasmolytic agents were administered more frequently in 1987 than in 1976. The use of glucagon had increased 20% between 1976 and 1987. Among 34 foreign institutions responding to the survey, 37% used glucagon and 45% used scopolamine butylbromide (Buscopan). Nevertheless, it is still controversial whether spasmolytic agents play a significant role in the performance and interpretation of a barium enema. Some radiologists routinely use a spasmolytic agent; others do so only selectively. PMID:8191992

Skucas, J

1994-06-01

302

Design of a vapor source for cesium-barium thermionic converters  

Microsoft Academic Search

A simple and reliable combined cesium-barium source containing pure barium and a multilayer cesium + pyrographite compound is designed for thermionic converters. The source can regulate the cesium and barium vapor pressures at a single point in the converter chamber; if necessary, the cesium concentration in the pyrographite can be changed so as to make the cesium vapor pressure P(Cs)

I. G. Gverdtsiteli; A. G. Kaladarishvili; V. G. Kashiia

1985-01-01

303

Mass barium carbonate poisoning with fatal outcome, lessons learned: a case series  

Microsoft Academic Search

INTRODUCTION: Barium, a heavy divalent alkaline metal, has long been known to cause human toxicity. The common mode is accidental ingestion and the common compound is Barium carbonate. Here we report an incident of food poisoning in 27 law enforcement personnel with rapidly developing sequelae and a high mortality due to ingestion of Barium carbonate contaminated flour. CASE PRESENTATION: One

Aniruddha Ghose; Abdullah Abu Sayeed; Amir Hossain; Ridwanur Rahman; Abul Faiz; Gofranul Haque

2009-01-01

304

40 CFR 721.10010 - Barium manganese oxide (BaMnO3).  

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false Barium manganese oxide (BaMnO3). 721.10010...Chemical Substances § 721.10010 Barium manganese oxide (BaMnO3 ). (a...The chemical substance identified as barium manganese oxide (BaMnO3 )...

2009-07-01

305

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...Chemical Substances § 721.10010 Barium manganese oxide (BaMnO3). (a...The chemical substance identified as barium manganese oxide (BaMnO3 )...

2010-07-01

306

21 CFR 201.304 - Tannic acid and barium enema preparations.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Tannic acid and barium enema preparations. 201.304 Section...Products § 201.304 Tannic acid and barium enema preparations. (a) It has...practice for tannic acid to be added to barium enemas to improve X-ray...

2010-04-01

307

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...Chemical Substances § 721.10010 Barium manganese oxide (BaMnO3 ). (a...The chemical substance identified as barium manganese oxide (BaMnO3 )...

2013-07-01

308

21 CFR 201.304 - Tannic acid and barium enema preparations.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 false Tannic acid and barium enema preparations. 201.304 Section...Products § 201.304 Tannic acid and barium enema preparations. (a) It has...practice for tannic acid to be added to barium enemas to improve X-ray...

2013-04-01

309

Discrete barite particles and barium as tracers of paleoproductivity in South Atlantic sediments  

Microsoft Academic Search

Geochemical analyses as well as X ray diffraction measurements were carried out on five sediment cores from the eastern Angola Basin and the equatorial divergence of the South Atlantic. Barite concentrations were calculated from total barium concentrations by subtracting the estimated barium background supplied by ``nonbarite'' barium carriers. Barite concentrations assessed by this geochemical method show a good correspondence to

Franz Gingele; Andreas Dahmke

1994-01-01

310

49 CFR 173.182 - Barium azide-50 percent or more water wet.  

Code of Federal Regulations, 2010 CFR

... 2010-10-01 2010-10-01 false Barium azide-50 percent or more water wet. 173...Other Than Class 1 and Class 7 § 173.182 Barium azideâ50 percent or more water wet. Barium azideâ50 percent or more water wet,...

2010-10-01

311

21 CFR 201.304 - Tannic acid and barium enema preparations.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 false Tannic acid and barium enema preparations. 201.304 Section...Products § 201.304 Tannic acid and barium enema preparations. (a) It has...practice for tannic acid to be added to barium enemas to improve X-ray...

2009-04-01

312

49 CFR 173.182 - Barium azide-50 percent or more water wet.  

Code of Federal Regulations, 2010 CFR

... 2009-10-01 2009-10-01 false Barium azide-50 percent or more water wet. 173...Other Than Class 1 and Class 7 § 173.182 Barium azideâ50 percent or more water wet. Barium azideâ50 percent or more water wet,...

2009-10-01

313

Predictive value of a diagnosis of colonic polyp on the double-contrast barium enema  

Microsoft Academic Search

The positive predictive value of a diagnosis of colonic polyp on the double-contrast barium enema was determined by analyzing 160 polypoid lesions reported in 105 patients. Of the 160 polyps, 139 were confirmed by endoscopy, surgery, or repeat barium enema for a positive predictive value of 87%. Twenty-one lesions were not confirmed despite repeat endoscopy, repeat barium enema, review of

David J. Ott; Deborah S. Ablin; David W. Gelfand; Isadore Meschan

1983-01-01

314

Modifications of Pt\\/alumina combustion catalysts by barium addition I. Properties of fresh catalysts  

Microsoft Academic Search

Platinum was deposited onto pure alumina as well as on alumina modified by addition of 7 and 15 wt.-% barium. The alumina hydroxyl groups were neutralized by barium addition and the surface of the modified support had a basic character. The introduction of barium decreased the accessible platinum area because of a sintering of the metal particles associated with a

Valérie Labalme; Nathalie Benhamou; Nolven Guilhaume; Edouard Garbowski; Michel Primet

1995-01-01

315

Determination of Barium in Bottled Drinking Water by Graphite Furnace Atomic Absorption Spectrometry  

Microsoft Academic Search

In relation to the wide environmental spread of barium and to its cardiovascular effects, barium levels were determined by graphite furnace atomic absorption spectrometry in 60 different brands of bottled water marketed in Italy.Matrix interferences were investigated in order to evaluate the use of an analytical calibration function rather than the much more time consuming addition technique.The barium content ranged

F. Fagioli; C. Locatelli; E. Lanciotti; G. Vallone; D. Mazzotta; A. Mugelli

1988-01-01

316

The biological production of marine suspended barite and the barium cycle in the Western Mediterranean Sea  

Microsoft Academic Search

Suspended particulate barium was measured in the Western Mediterranean along 4 profiles sampled during the PHYCEMED 1 cruise in 1981. The non-terrigenous fraction of particulate barium (i.e. excess Ba; Baxs) can account for up to 96% of total barium. This fraction follows the barite settling and dissolution rate model we described earlier for the Atlantic Ocean, confirming barite as the

F. DEHAIRSI; C. E. Lambert; R. Chesselet; N. Risler

1987-01-01

317

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

318

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

Microsoft Academic Search

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

R Dallam

1987-01-01

319

Ten years trends (1984-1993) in the precipitation chemistry in central Austria  

NASA Astrophysics Data System (ADS)

Since 1984, wet precipitation samples have been collected from five sampling sites in the eastern Alpine region of Austria. The chemical analysis performed included pH, NH 4+, Na +, K +, Ca 2+, Mg 2+, Cl -, NO 3- SO 42- and precipitation amount. These data were used to determine the 10 years (1984-1993) trends in precipitation chemistry and deposition for all major ions. The statistical data treatment by the use of least-squares linear regression revealed a significant decrease of sulfate and hydrogen ion concentrations and depositions at all sites in consideration (above 65% for hydrogen ion and over 33% for sulfate concentration and 40% for hydrogen and 36% for sulfate deposition). An effort is made to explain the acidity decrease not only by the parallel decrease of sulfate concentration but by the participation of the other constituents of the wet precipitation events. It has been found that when the hydrogen ion concentration decrease is stronger than that of sulfate ion concentrations a compensation mainly by ammonium ion concentration increase is achieved. On the contrary, when the hydrogen ion concentration decrease is weaker than sulfate concentration decrease, a calcium ion concentration decrease is present for the sites in consideration. The results obtained indicate that the precipitation chemistry in Central Austria follows the global trends of controlled reduction of atmospheric acidity.

Puxbaum, H.; Simeonov, V.; Kalina, M. F.

320

Treatment of cotton textile wastewater using lime and ferrous sulfate.  

PubMed

This technical note summarizes the results of a textile wastewater treatment process aiming at the destruction of the wastewater's color by means of coagulation/flocculation techniques using ferrous sulfate and/or lime. All the experiments were run in a pilot plant that simulated an actual industrial wastewater treatment plant. Treatment with lime alone proved to be very effective in removing the color (70-90%) and part of the COD (50-60%) from the textile wastewater. Moreover, the treatment with ferrous sulfate regulating the pH in the range 9.0+/-0.5 using lime was equally effective. Finally, the treatment with lime in the presence of increasing doses of ferrous sulfate was tested successfully, however; it proved to be very costly mainly due to the massive production of solids that precipitated. PMID:12691912

Georgiou, D; Aivazidis, A; Hatiras, J; Gimouhopoulos, K

2003-05-01

321

Effects of different fabrication techniques on the Yttrium-Barium-Copper oxide high temperature superconductor  

NASA Astrophysics Data System (ADS)

This study examines how several different parameters were changed in the yttrium-barium-copper oxide superconductor when the fabrication techniques were altered by using different barium precursors, including barium peroxide and barium carbonate; sintering at different temperatures, including 850, 900, 950 C; and annealing in an above ambient oxygen environment. Twelve different pellets were fabricated, and measurements were taken on them which included density, X-ray diffraction, critical temperature, critical current density, and magnetic susceptibility. The results showed that the barium peroxide derived samples had higher densities, better critical current densities and lower resistivities in the normal state.

Rhea, Paul A.

1988-12-01

322

Separation of lanthanum, hafnium, barium and radiotracers yttrium-88 and barium-133 using crystalline zirconium phosphate and phosphonate compounds as prospective materials for a Ra223 radioisotope generator  

Microsoft Academic Search

Crystalline hybrid organic\\/inorganic ion exchangers based on zirconium phosphate and phosphonate compounds were evaluated for application in radium-223 generator for radiopharmaceutical applications. Various compositions were synthesized and the selectivity of these materials was determined for inactive lanthanum, hafnium and barium, and radiotracers yttrium-88 and barium-133. The hybrid materials show very efficient lanthanum\\/barium separation; the response for zirconium phosphate was even

Teresia Möller; Naima Bestaoui; Melissa Wierzbicki; Todd Adams; Abraham Clearfield

2011-01-01

323

Separation of barium and lantanium on aluminium oxide  

Microsoft Academic Search

Lanthanum 140 having a short period of half-decay is sufficient to be used as a radioactive indicator in chemistry investigations of lanthanides and actinides. Preparates based on lanthanum 140 allow one to carry out studies to determine rare-earth elements in technological products and raw materials. This work was devoted to the study of the separations of lanthanum 140 from barium

S. Khuzaev; N. A. Mirzaeva; A. Sultanov

1993-01-01

324

Geochemistry of Barium in Sediments of the Western Black Sea  

Microsoft Academic Search

During two cruises with RV POSEIDON and RV METEOR to the western Black Sea (west of Crimean Peninsula) in 2004 and 2007, respectively, sediment cores were taken along a transect from 500 to 1700 m water depth. Pore water and solid phase investigations aimed at unraveling the geochemical behaviour of barium in this anoxic water column and sedimentary environment. In

S. Kasten; K. Bogus; M. Jones; S. Henkel; C. Maerz; K. Pfeifer; R. Seifert

2008-01-01

325

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 ...

326

Barium Cloud Growth and Striation in a Conducting Background  

Microsoft Academic Search

Previous calculations of barium cloud growth did not give reasonable estimates of Striation scale size and onset time because they assumed either no ionospheric end shorting or no ion diffusion (all modes unstable) or strong shorting (all modes stable). We derive a set of equations that includes both finite end shorting and ion diffusion and solve by a new numerical

J. N. Shiau; A. Simon

1974-01-01

327

Dielectric Behavior of Nano Barium Titanate Filled Polymeric Composites  

NASA Astrophysics Data System (ADS)

Rapid growth of electronic industry requires development of new materials that combine the high dielectric constant intrinsic to ferroelectric ceramic materials with easy processing characteristics of polymers. Ceramic-polymeric composites possess interesting properties for a variety of electronic applications including passive electronic devices. In fact, polymer-ceramic materials have drawn lot attention for use in microelectronic packaging, because they can give higher performance with lower cost, size and weight. In this work, attempts are made to prepare ceramic polymer composites followed by characterization of dielectric properties. The Barium Titanate ceramic powders are synthesized using the hydrothermal process. Crystal structure and crystallite size of particles are determined using X-ray diffraction. Silane treatment is carried out on Barium Titanate powder to increase its compatibility with polymer, followed with preparation of ceramic polymer composites. Epoxy and polyvinyledene fluoride (PVDF) polymers are used as matrices for preparation of the composites. The proportion of nanopowder is varied from 60 to 90 wt%. Dielectric properties such as volume resistivity, dielectric constant, dissipation factor are evaluated. Results indicate that the dielectric constant and dissipation factor vary between 18 -140 and 0.01 to 0.09, respectively as the relative ratio of polymer and silane modified Barium Titanate is varied. Specifically, at 90 wt% of 0.1 wt% silane modified Barium Titanate, the highest dielectric constant of 140 along with dissipation factor of 0.07 is obtained in the epoxy based system.

Pratap, A.; Joshi, N. J.; Rakshit, P. B.; Grewal, G. S.; Shrinet, V.

328

Permittivity of Solid Solutions of Barium and Lead Titanate.  

National Technical Information Service (NTIS)

An investigation was made of the effect on the dielectric properties of barium titanate (BaTiO3) by the addition of small percentages (0 to 10 percent) of lead titanate (PbTiO3). Measurements were made at 1 kc/s within the temperature range 0 to 200C. Inc...

G. W. Marks L. A. Monson

1967-01-01

329

Study of Barium Strontium Titanate Thin Film Doped by Indium  

Microsoft Academic Search

We have developed Barium Strontium Tinanate (BST) doped by Indium as soft dopant on Pt\\/Si substrate using chemical solution deposition method followed by spin coating. The specimen is then examined by XRF to identify the chemical content, SEM to study the morphology of the films, XRD to calculate the grain size, and electrometer Keithley 6517A to obtain the hysteresis curves.

M. Hikam; B. Soegijono; Y. Iriani; I. Mudzakir; D. Fasquelle

2009-01-01

330

How does sodium sulfate crystallize? Implications for the decay and testing of building materials  

Microsoft Academic Search

The fundamental behavior of sodium sulfate crystallization and induced decay in concrete and other building materials is still poorly understood, resulting in some misinterpretation and controversy. We experimentally show that under real world conditions, both thenardite (Na2SO4) and mirabilite (Na2SO4·10H2O) precipitate directly from a saturated sodium sulfate solution at room temperature (20°C). With decreasing relative humidity (RH) and increasing evaporation

Carlos Rodriguez-Navarro; Eric Doehne; Eduardo Sebastian

2000-01-01

331

Preparation and Structure Analysis of Chondroitin Sulfate from Pig Laryngeal Cartilage  

Microsoft Academic Search

The chondroitin sulfate with high purity was extracted by papain hydrolysis, isolated and purified by tricloroacetic acid, alcohol precipitation, dialysis and DEAE-Sepharose Fast Flow ion exchange column chromatography. The structure was identified by biological enzymolysis and spectral analysis. GC data exhibited that neutral monosaccharide in chondroitin sulfate only included 0.84% of xylose and 1.28% of galactose. IR data showed that

Anlin Li; Shuangli Xiong

2010-01-01

332

Recovery of fission product rare earth sulfates from Purex 1WW  

Microsoft Academic Search

Cerium-144 and promethium-147, accompanied by rare earths resulting from fission or decay can be removed from Purex 1WW in >90% yield as an insoluble, crystalline sodium-rare earth double sulfate. Precipitation is initiated by a one-to-three hour equilibration at 90°C and centrifugation at 90°C to take advantage of the lower solubility of the double sulfate salt at a higher temperature. The

E. J. Wheelwright; W. H. Swift

1961-01-01

333

Organic Substrates in Bioremediation of Acidic Saline Drainage Waters by Sulfate-Reducing Bacteria  

Microsoft Academic Search

Deep drains used to manage shallow saline water tables in the Western Australian agricultural region discharge acidic, saline\\u000a drainage water with high concentrations of metals. The activity of sulfate-reducing bacteria can treat these waters by generating\\u000a alkalinity in the form of bicarbonate and by generating sulfide, which removes metals from solution as sulfide precipitates.\\u000a Bacterial sulfate reduction was strongly influenced

Talitha C. Santini; Brad P. Degens; Andrew W. Rate

2010-01-01

334

Can drying and re-wetting of magnesium sulfate salts lead to damage of stone?  

Microsoft Academic Search

Magnesium sulfate salts have been linked to the decay of stone in the field and in laboratory experiments, but the mechanism\\u000a of damage is still poorly understood. Thermomechanical analysis shows that expansion of stone contaminated with magnesium\\u000a sulfate salts occurs during drying, followed by relaxation of the stress during dehydration of the precipitated salts. We\\u000a applied thermogravimetric analysis and X-ray

Enrica Balboni; Rosa M. Espinosa-Marzal; Eric Doehne; George W. Scherer

2011-01-01

335

Chemoenzymatic Design of Heparan Sulfate Oligosaccharides*  

PubMed Central

Heparan sulfate is a sulfated glycan that exhibits essential physiological functions. Interrogation of the specificity of heparan sulfate-mediated activities demands a library of structurally defined oligosaccharides. Chemical synthesis of large heparan sulfate oligosaccharides remains challenging. We report the synthesis of oligosaccharides with different sulfation patterns and sizes from a disaccharide building block using glycosyltransferases, heparan sulfate C5-epimerase, and sulfotransferases. This method offers a generic approach to prepare heparan sulfate oligosaccharides possessing predictable structures.

Liu, Renpeng; Xu, Yongmei; Chen, Miao; Weiwer, Michel; Zhou, Xianxuan; Bridges, Arlene S.; DeAngelis, Paul L.; Zhang, Qisheng; Linhardt, Robert J.; Liu, Jian

2010-01-01

336

Chemoenzymatic design of heparan sulfate oligosaccharides.  

PubMed

Heparan sulfate is a sulfated glycan that exhibits essential physiological functions. Interrogation of the specificity of heparan sulfate-mediated activities demands a library of structurally defined oligosaccharides. Chemical synthesis of large heparan sulfate oligosaccharides remains challenging. We report the synthesis of oligosaccharides with different sulfation patterns and sizes from a disaccharide building block using glycosyltransferases, heparan sulfate C(5)-epimerase, and sulfotransferases. This method offers a generic approach to prepare heparan sulfate oligosaccharides possessing predictable structures. PMID:20729556

Liu, Renpeng; Xu, Yongmei; Chen, Miao; Weïwer, Michel; Zhou, Xianxuan; Bridges, Arlene S; DeAngelis, Paul L; Zhang, Qisheng; Linhardt, Robert J; Liu, Jian

2010-08-21

337

Sulfate Ions in Titania Polymorphs  

Microsoft Academic Search

Sol-gel titania was sulfated by using sulfuric acid as hydrolysis catalyst, or by impregnating with ammonium sulfate fresh samples prepared with nitric acid or ammonium hydroxide as hydrolysis catalyst. Samples were characterized with X-ray powder diffraction, infrared spectroscopy, thermogravimetry and atomic absorption spectroscopy. Sulfate ions were found anchored to brookite and anatase phases, because they have short O—O atomic bond

X. Bokhimi; A. Morales; E. Ortíz; T. López; R. Gómez; J. Navarrete

2004-01-01

338

Barium partitioning in coccoliths of Emiliania huxleyi  

NASA Astrophysics Data System (ADS)

The coccolithophore Emiliania huxleyi was grown in seawater under different Ba concentrations. The relationship of coccolith Ba/Ca ratio and seawater Ba/Ca ratio was found to be linear. The linear regression yields the apparent Ba exchange coefficient of 0.10. Our data support a recently proposed generic model (Langer G., Gussone N., Nehrke G., Riebesell U., Eisenhauer A., Kuhnert H., Rost B., Trimborn S., and Thoms S. (2006) Coccolith strontium to calcium ratios in Emiliania huxleyi: the dependence on seawater strontium and calcium concentrations. Limnol. Oceanogr.51, 310-320.) developed for explaining apparent exchange coefficients of metabolically inert divalent trace metals, such as Sr, in E. huxleyi. This model represents the first approach combining cell physiological processes and data from inorganic precipitation experiments, which quantitatively explains coccolith apparent Sr and Ba exchange coefficients.

Langer, Gerald; Nehrke, Gernot; Thoms, Silke; Stoll, Heather

2009-05-01

339

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

340

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?

2009-01-22

341

Mixture of sulfate and nitrate in coastal atmospheric aerosols: individual particle studies in Qingdao (36°04?N, 120°21?E), China  

Microsoft Academic Search

Atmospheric aerosol particles were collected at Qingdao (36°04?N, 120°21?E) in October 1996 in order to investigate the characteristics of aerosols in coastal areas of China. Morphologies and element compositions of individual particles were analyzed using a transmission electron microscope and an energy dispersive X-ray spectrometer. Particulate sulfate and nitrate were detected with nitron and barium chloride films pre-coated on the

Daizhou Zhang; Guang-Yu Shi; Yasunobu Iwasaka; Min Hu

2000-01-01

342

Spectral identification of hydrated sulfates on Mars and comparison with acidic environments on Earth  

NASA Astrophysics Data System (ADS)

We interpret recent spectral data of Mars collected by the Mars Exploration Rovers to contain substantial evidence of sulfate minerals and aqueous processes. We present visible/near-infrared (VNIR), mid-IR and Mössbauer spectra of several iron sulfate minerals and two acid mine drainage (AMD) samples collected from the Iron Mountain site and compare these combined data with the recent spectra of Mars. We suggest that the sulfates on Mars are produced via aqueous oxidation of sulfides known to be present on Mars from Martian meteorites. The sulfate-rich rock outcrops observed in Meridiani Planum may have formed in an acidic environment similar to AMD environments on Earth. Because microorganisms are typically involved in the oxidation of sulfides to sulfates in terrestrial AMD sites, sulfate-rich rock outcrops on Mars may be a good location to search for evidence of life on that planet. Whether or not life evolved on Mars, following the trail of sulfate minerals is likely to lead to aqueous processes and chemical weathering. Our results imply that sulfate minerals formed in Martian soils via chemical weathering, perhaps over very long time periods, and that sulfate minerals precipitated following aqueous oxidation of sulfides to form the outcrop rocks at Meridiani Planum.

Bishop, Janice L.; Darby Dyar, M.; Lane, Melissa D.; Banfield, Jillian F.

2004-10-01

343

Application of Biostimulation for Remediation of Sulfate-Contaminated Groundwater at a Mining Site  

NASA Astrophysics Data System (ADS)

There is growing concern regarding sulfate contamination of groundwater. One innovative in-situ remediation option under investigation is biostimulation through addition of electron-donor amendments to enhance sulfate reduction. Two pilot-scale ethanol-injection tests were conducted at a former uranium mining site that is contaminated with sulfate and nitrate (with a lack of heavy metals), and for which there appears to be minimal natural attenuation of sulfate. The first test was a push-pull test that had a limited zone of influence, while the second test was a single-well injection test in which additional downgradient wells were monitored. For both tests, sulfate concentrations began to decline within a few weeks of injection, after nitrate concentrations were significantly reduced. Concomitantly, aqueous concentrations of manganese, iron, and hydrogen sulfide increased from background. Monitoring over many months revealed that the declines in sulfate concentration conformed to exponential decay, with first-order decay rates of approximately 0.01 /d. Analysis of sulfur stable isotope data indicated that the decrease in sulfate concentrations was microbially mediated. The results also indicated that sulfides formed during sulfate reduction may have undergone partial re-oxidation. This study illustrates the feasibility of using ethanol injection for remediation of sulfate-contaminated groundwater. However, re-oxidation of sulfides (both metal sulfide precipitates and hydrogen sulfide gas) is a potential issue of significance that would need to be addressed.

Miao, Z.; Carroll, K. C.; Carreon, C.; Brusseau, M. L.

2011-12-01

344

Sulfation of fucoidin in focus embryos: III. Required for localization in the rhizoid wall  

PubMed Central

Zygotes of the brown alga Fucus distichus L. Powell accumulate a sulfated polysaccharide (fucoidin) in the cell wall at the site of rhizoid formation. Previous work indicated that zygotes grown in seawater minus sulfate do not sulfate the preformed fucan (an unsulfated fucoidin) but form rhizoids. Under these conditions, we determined whether sulfation of the fucan is required for its localization in the rhizoid wall. This was accomplished by developing a specific stain for both the fucan and fucoidin. Using a precipitin assay, we demonstrated in vitro that the lectin ricin (RCA(I)) specifically complexes with both the sulfated and desulfated polysaccharide. No precipitate is observed when either is incubated in 0.1 M D-galactose or when RCA(I) is mixed with laminarin or alginic acid, the other major polysaccharides in Fucus. RCA(I) conjugated with fluorescein isothiocyanate (FITC) is also shown to bind specifically to fucoidin using a filter paper (DE81) assay. When added to zygotes, RCA(I)-FITC binds only to the site of fucoidin localization, i.e., the rhizoid cell wall. However, RCA(I)-FITC is not observed in the rhizoid wall of zygotes grown in the absence of sulfate. This observation is not due to inability of RCA(I)-FITC to bind to the fucan in vivo. Chemically desulfated cell walls that contained fucoidin in the rhizoid wall bind RCA(I)-FITC only in the rhizoid region. Also, the concentration of fucose-containing polymers and polysaccharides that form precipitates with RCA(I) is the same in embryos grown in the presence or absence of sulfate. If sulfate is added back to cultures of zygotes grown without sulfate, fucoidin is detected at the rhizoid tip by RCA(I)-FITC several hours later. These results support the conclusion that the enzymatic sulfation of the fucan is a modification of the polysaccharide required for its localization and/or assembly into a specific region of the cell wall.

Hogsett, WE; Quatrano, RS

1978-01-01

345

Mechanisms of sulfate removal from subsurface calcium chloride brines: Heletz-Kokhav oilfields, Israel  

NASA Astrophysics Data System (ADS)

The evolution of the Ca-chloride brines in the Heletz Formation, Lower Cretaceous, in the southern coastal plain of Israel was reconstructed through the study of its sulfate concentration and isotopic composition. Particular emphasis was given to the brine-oil interaction in the oilfields and to the sulfate depletion and lower SO 4 /Cl ratio in brines in contact with hydrocarbons (oil brines) relative to "oil-free" from dry wells in the same oilfields. A method is presented for a calculation of the amount of sulfate removed from the original seawater in the various stages of its evolution to Ca-chloride brine. These stages include evaporation, dolomitization, and sulfate reduction in different stages of its evolution, from early diagenetic processes to the contact with crude oil. In the present study, based on the 34 S SO 4 and SO 4 /Cl ratio, it was found that in the Heletz brines most of the sulfate (80-94%) was removed from the original seawater prior to their interaction with the hydrocarbons and only a negligible fraction of few percent of the sulfate was removed during the crude oil-water contact. The Ca-chloride brines evolved from Messinian (Upper Miocene) seawater that underwent evaporation during the desiccation of the Mediterranean. Sulfate was removed from Messinian lagoon (s) during gypsum precipitation due to evaporation and dolomitization. Bacterial sulfate reduction further depleted the brine in sulfate and changed its isotopic composition, from its original Miocene seawater composition of 34 S SO 4 ~ 20%o, 26%o. Overall, some 50% of the original sulfate, as normalized to chloride, was removed from the original lagoon through the above processes, mostly by gypsum precipitation. Eastward migration of the Messinian Ca-Chloride brine into the Heletz Formation was accompanied by dolomitization of the country rock. Final depletion of sulfate from the brines took place, and possibly still occurs, in the presence of crude oil in the oilfields. The two oil-producing fields, Heletz and Kokhav, occupy different areas on a Rayleigh distillation diagram. Sulfate depletion in both fields is accompanied by an increase in 34 S SO 4 , which reaches a maximum value of 59%o. The above correlation is explained by bacterial sulfate reduction facilitated by the contact with the crude. Samples collected from the same boreholes at time intervals of several months show two opposing trends: sulfate concentration decrease accompanied by increase in 34 S SO 4 , and vice versa. While the first can be explained as in situ bacterial sulfate reduction, the latter attest to subsurface brine migration, as would be expected in oil-producing fields.

Gavrieli, Ittai; Starinsky, Avraham; Spiro, Baruch; Aizenshtat, Zeev; Nielsen, Heimo

1995-09-01

346

Preliminary assessment of potential health hazards associated with barium leached from glazed ceramicware.  

PubMed

Ceramic glazes contain several elements which have the potential to leach into food or beverages that are held or stored in ceramicware. Recently, barium salts have been investigated as one of the alternatives to lead in frit formulations for glazes. This preliminary evaluation addresses the potential health hazards associated with barium at levels that might leach from glazed ceramicware. A set of specialty ceramicware, consisting of five teacups and a pitcher, was examined for extractable barium. Exposure to barium that adults (18-44 years) might encounter using the vessels for coffee, tea, or orange juice was estimated. The exposure estimate was derived from values for intakes of the beverages and for the barium migration from glazed ceramicware test samples. An established reference dose (RfD) for barium exposure for the critical effect of hypertension was identified. The potential hazard associated with the leaching of barium from glazed ceramicware varied with the level of use. Consuming beverages in amounts up to the 95th percentile would not result in total barium intake in amounts that exceed the RfD; consuming large quantities (> 95th percentile) of beverages such as tea or coffee from glazed vessels might. This suggests that for a small portion of the population of users, intake of barium may be in quantities that warrant further consideration as a potential health hazard. Analyses of a broad sample of ceramicware and study of barium leaching behaviour under actual use conditions are needed to assess further the significance of these findings. PMID:9328533

Assimon, S A; Adams, M A; Jacobs, R M; Bolger, P M

1997-07-01

347

Precipitation Type Applet  

NSDL National Science Digital Library

This applet provides a simulation of the type of precipitation that results from adjusting the temperature (dry bulb and wet bulb) at different altitudes. An updraft in the cloud can be produced in order to see its influence on precipitation. The precipitation types that are simulated include snowflakes/ice crystals, supercooled droplets, raindrops, drizzle, sleet, snow grains, and freezing rain or drizzle on the ground.

Whittaker, Tom

348

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

349

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.

Spangler, Tim

2005-06-24

350

Evaporation, Condensation, and Precipitation  

NSDL National Science Digital Library

After completion of this project students should have an understanding of evaporation, condensation, and precipitation in the water cycle. Use the websites provided to answer the questions. Record your answers on the spreadsheet provided. Do you understand how the water cycle works? Begin by watching this short video about the water cycle.water cycle video Use the website to define condensation, precipitation, and evaporation?water cycle List the different types of precipitation from the site.types of precipitation Follow the directions to the experiment on this website to get a better understanding of how evaporation takes ...

Brown, Miss

2009-10-21

351

Precipitation of relativistic electrons  

NASA Astrophysics Data System (ADS)

Precipitation of relativistic electrons observed in Earth's auroral zone occurs on the morning and evening local hours. The morning precipitation is impulsive with durations of about 0.25s (microbursts). The evening precipitation is relatively smooth with variations on minute time scales. Mechanisms for the relativistic electron precipitation remain unknown. Microbursts with relativistic energies come from polar orbiting satellites and they have not been seen on balloon-borne detectors. Relativistic electrons on the evening hours are detected by balloonborne detectors and have not been reported by satellites. We anticipate the upcoming missions could resolve this dilemma.

Parks, G. K.; Lee, J. J.; Lee, E. S.; Sample, J.; McCarthy, M.

2012-11-01

352

Integral membrane heparan sulfate proteoglycans  

Microsoft Academic Search

Heparan sulfate is a regulatory polysac- charide. It modulates specific growth factor-receptor in- teractions, accelerates the formation of specific proteinase- proteinase inhibitor complexes, and mediates interactions of the cell surface with several enzymes and structural proteins. It abounds on the surfaces of embryonic cells, respecting or outlining morphogenetic rather than histo- logical boundaries. This cell surface-associated heparan sulfate is implanted

GUIDO DAVID

1993-01-01

353

Prospective comparison of double contrast barium enema plus flexible sigmoidoscopy v colonoscopy in rectal bleeding: barium enema v colonoscopy in rectal bleeding.  

PubMed Central

Rectal bleeding often heralds serious colonic disease. The literature suggests that colonoscopy is superior to barium enema plus sigmoidoscopy, although no good comparative studies exist. Seventy one patients with overt rectal bleeding had prospectively flexible sigmoidoscopy, double contrast barium enema and colonoscopy completed independently. Against the gold standard, the sensitivity and specificity of colonoscopy were 0.69 and 0.78 respectively for a spectrum of colonic lesions, while for combined flexible sigmoidoscopy and double contrast barium enema these values were 0.80 and 0.56, respectively. When assessing adenoma or carcinoma, colonoscopy was more sensitive at 0.82 v 0.73, while flexible sigmoidoscopy plus double contrast barium enema was superior for detecting diverticular disease. The positive predictive value for colonoscopy was 0.87 against 0.81 for flexible sigmoidoscopy and double contrast barium enema. This study confirms that colonoscopy should be a first line investigation in subjects likely to require biopsy or therapeutic intervention.

Irvine, E J; O'Connor, J; Frost, R A; Shorvon, P; Somers, S; Stevenson, G W; Hunt, R H

1988-01-01

354

Sulfation of von Willebrand factor  

SciTech Connect

von Willebrand factor (vWF) is a multimeric adhesive glycoprotein essential for normal hemostasis. We have discovered that cultured human umbilical vein endothelial cells incorporate inorganic sulfate into vWF. Following immunoisolation and analysis by polyacrylamide or agarose gel electrophoresis, metabolically labeled vWF was found to have incorporated (35S)-sulfate into all secreted multimer species. The time course of incorporation shows that sulfation occurs late in the biosynthesis of vWF, near the point at which multimerization occurs. Quantitative analysis suggests the presence, on average, of one molecule of sulfate per mature vWF subunit. Virtually all the detectable sulfate is released from the mature vWF subunit by treatment with endoglycosidases that remove asparagine-linked carbohydrates. Sulfated carbohydrate was localized first to the N-terminal half of the mature subunit (amino acids 1 through 1,365) by partial proteolytic digestion with protease V8; and subsequently to a smaller fragment within this region (amino acids 273 through 511) by sequential digestions with protease V8 and trypsin. Thus, the carbohydrate at asparagine 384 and/or 468 appears to be the site of sulfate modification. Sodium chlorate, an inhibitor of adenosine triphosphate-sulfurylase, blocks sulfation of vWF without affecting either the ability of vWF to assemble into high molecular weight multimers or the ability of vWF multimers to enter Weible-Palade bodies. The stability of vWF multimers in the presence of an endothelial cell monolayer also was unaffected by the sulfation state. Additionally, we have found that the cleaved propeptide of vWF is sulfated on asparagine-linked carbohydrate.

Carew, J.A.; Browning, P.J.; Lynch, D.C. (Harvard Medical School, Boston, MA (USA))

1990-12-15

355

Formation of yttrium barium cuprate powder at low temperatures  

SciTech Connect

Yttrium barium cuprate can be formed at temperatures below 800{degrees}C from mixed oxides and carbonate if a low-oxygen-pressure atmosphere is used. This eliminates the formation of a high-oxygen-content nonsuperconducting phase which has been previously shown to form at lower temperatures. Reaction of barium carbonate and the oxides of copper and yttrium at temperatures as low as 750{degrees}C in reducing atmospheres is shown to form tetragonal YBa{sub 2}Cu{sub 3}O{sub x} with x about 6. This compound can then be oxidized by cooling in an oxidizing atmosphere to obtain the desired x value of about 7.

Lay, K.W. (Research and Development Center, General Electric Co., Schenectady, NY (US))

1989-04-01

356

Oxygen tracer diffusion in donor doped barium titanate  

NASA Astrophysics Data System (ADS)

Oxygen exchange with the ambient atmosphere and oxygen diffusion are assumed to play a decisive role in the re-oxidation process of positive temperature coefficient (PTC) resistors based on donor doped barium titanate. 18O tracer experiments with subsequent time-of-flight secondary ion mass spectrometry (ToF-SIMS) measurements were thus carried out to investigate the oxygen diffusion properties of donor doped barium titanate. Fast grain boundary diffusion was found at temperatures between 750 °C and 900 °C. Moreover, evidence is given for a position dependent diffusion coefficient close to the surface. The secondary phase developing during the production process is shown to be Ti-rich and hardly any oxygen tracer exchange with this secondary phase could be observed. This suggests that grain boundary diffusion does not take place via such secondary phases. Rather, evidence of diffusion along an oxygen vacancy enriched space charge region is found.

Frömling, T.; Hou, J.; Preis, W.; Sitte, W.; Hutter, H.; Fleig, J.

2011-08-01

357

Photoionization and photoelectric loading of barium ion traps  

SciTech Connect

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

Steele, A. V.; Churchill, L. R.; Griffin, P. F.; Chapman, M. S. [School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430 (United States)

2007-05-15

358

Spectroscopy of barium attached to superfluid helium clusters  

NASA Astrophysics Data System (ADS)

To complement the data on absorption spectra of alkaline earth atoms attached to superfluid helium clusters we are reporting on barium atoms attached to 4HeN. The absorption spectrum of the lowest singlet transition is blue-shifted and strongly broadened compared to the corresponding unperturbed Ba (6s6p1Po1?6s21S0) transition in accord with the observations on Sr and Ca added to HeN [F. Stienkemeier, F. Meier, and H.O. Lutz: J. Chem. Phys. 107(24), 10816 (1997)]. Moreover, we compare the asymptotic values of shift and width of the excitation spectrum with increasing helium cluster size He ( 1000 up to 10000) to those found for barium atoms in bulk liquid helium.

Stienkemeier, F.; Meier, F.; Lutz, H. O.

359

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

360

Influence of oxygen precipitation on copper precipitation in Czochralski silicon  

NASA Astrophysics Data System (ADS)

The influence of oxygen precipitation on copper precipitation in Czochralski silicon was investigated by means of defect etching, optical microscopy, and Fourier transform infrared spectrometer. It was found that the density, distribution, and morphology of copper precipitation can be influenced by oxygen precipitate sequence significantly. The spherelike copper precipitates uniformly distributed along the whole cross section were generated only in the specimens oxygen precipitation at the very beginning of the heating treatment. While in the specimens, copper precipitation firstly, the large star-like precipitate colonies was generated due to the repeated nucleation mechanism. Additionally, the bulk microdefects (BMDs) density of the latter was higher than the former. The influence of oxygen precipitation nuclei, which was formed during 750 °C for 8 h annealing, on copper precipitation was similar to that of oxygen precipitation, indicated that the initial density and distribution of oxygen precipitation nuclei were the main factors to decided copper precipitation.

Xu, Jin; Wang, Nating; Yang, Deren

2012-05-01

361

Oriented barium ferrite straight-field focusing structure  

Microsoft Academic Search

An oriented barium ferrite straight-field structure for focusing the electron beam of a klystron has been designed and successfully manufactured. The structure is a hollow tapered hexagon, circumscribed about a9frac{3}{4}-inch outside diameter and3frac{7}{8}-inch inside diameter. The overall height, including pole pieces, is9frac{3}{8}inches. The peak axial field strength, before field shaping, is 1000 gauss, and transverse fields are held to 1

I. Wagner

1970-01-01

362

Separation of barium and lantanium on aluminium oxide  

SciTech Connect

Lanthanum 140 having a short period of half-decay is sufficient to be used as a radioactive indicator in chemistry investigations of lanthanides and actinides. Preparates based on lanthanum 140 allow one to carry out studies to determine rare-earth elements in technological products and raw materials. This work was devoted to the study of the separations of lanthanum 140 from barium 140 utilizing inorganic sorbents.

Khuzaev, S.; Mirzaeva, N.A.; Sultanov, A.

1993-12-31

363

Analysis of the sixth spectrum of barium: Ba VI  

Microsoft Academic Search

The spectrum of barium was photographed in the 300 Å-1240 Å wavelength region on a 3-m normal incidence spectrograph at the Antigonish laboratory. The source used was a triggered spark. All five levels of the ground configuration 5s25p3 and 42 of 44 levels of the 5s5p4 + 5s25p25d + 5s25p26s configurations of Ba VI have been established. One hundred and

A. Tauheed; Y. N. Joshi

1994-01-01

364

Substrate effects on the crystalline orientation of barium hexaferrite films  

Microsoft Academic Search

Insitu crystallized barium hexaferrite films have been deposited with a target-facing sputtering system under previously optimized conditions on four different substrates which are: SiO2, ZnO, Gd3Ga5O12, and Al2O3. By using several structural and magnetic characterizations different growth mechanisms were put forward according to the chosen substrate. On amorphous silica there is an important Ba affinity for SiO2, resulting in the

E. Lacroix; P. Gerard; G. Marest; M. Dupuy

1991-01-01

365

Texture and Microstructural Development in Gelcast Barium Hexaferrite  

SciTech Connect

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

Hovis, David B. [Northwestern University, Evanston; Faber, Katherine T. [Northwestern University, Evanston; Kenik, Edward A [ORNL

2008-01-01

366

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

367

The positive temperature coefficient of resistivity in barium titanate  

Microsoft Academic Search

Positive temperature coefficient of resistivity (PTCR) materials have become very important components, and among these materials\\u000a barium titanate compounds make up the most important group. When properly processed these compounds show a high PTCR at the\\u000a Curie temperature (the transition temperature from the ferroelectric tetragonal phase to the paraelectric cube phase). In\\u000a the first half of this paper literature related

B. Huybrechts; K. Ishizaki; M. Takata

1995-01-01

368

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

369

Preparation and microwave absorption properties of barium ferrite nanorods  

Microsoft Academic Search

Barium hexaferrite nanorods were successfully prepared using a sol–gel technique with polymethylmethacrylate as a template. The magnetic nanorods with diameters about 60nm and lengths about 300nm are visible from FESEM images. The electromagnetic parameters of BaFe12O19 with different shapes were measured with vector network analyzer at 5–15GHz. The results show that the microwave absorption properties of rod-shaped BaFe12O19 are better

Guohong Mu; Na Chen; Xifeng Pan; Haigen Shen; Mingyuan Gu

2008-01-01

370

AC Conducitivity in Bismuth-Substituted Barium Hexaferrites  

Microsoft Academic Search

Bismuth substituted barium hexaferrites in the composition series BaO·(6-x) Fe2 O3·x Bi2 O3 with 0

M. Pal; P. Brahma; D. Chakravorty

1994-01-01

371

Absolute ionisation functions for electron impact with barium  

Microsoft Academic Search

Absolute ionisation functions sigma n+(E)(n=1,2,3,4) and the total ionisation function sigma tot(E) for electron impact with barium have been determined for energies up to 600 eV. Modified crossed-beam techniques were applied using the excitation function of the light from the resonance transition as a reference standard for the cross sections. A time-of-flight device was used to separate ions with different

J.-M. Dettmann; F. Karstensen

1982-01-01

372

Acute barium intoxication following ingestion of soap water solution.  

PubMed

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

2012-10-01

373

The Electrical Conductivity of Strontium-Barium Niobate  

NASA Astrophysics Data System (ADS)

We propose an explanation for the high electrical conductivity of the ferroelectric strontium-barium niobate. As the temperature T approaches the ferroelectric transition T c, the static dielectric constant \\varepsilon(0) diverges when a soft mode occurs. This divergence of \\varepsilon(0) reduces the donor binding energy, and increases the effective Bohr radius of the donor. The electrons bound to the donors become unbound, and the material becomes conductive.

Mahan, G. D.; Sofo, J. O.

2013-07-01

374

The distribution of rubidium, cesium and barium in the oceans  

Microsoft Academic Search

Rubidium, cesium and barium have been determined in several oceanic profiles by a neutron activation procedure based on the extraction of salt from 100 ml. samples by freeze-drying. Assuming a constant strontium-chlorinity ratio of 0.0425, strontium was used as an internal flux monitor. For 19.0% chlorinity the average concentrations of these three elements are 125 g Rb\\/1. (10 samples), 0.30

Ernst Bolter; Karl K. Turekian; Donald F. Schutz

1964-01-01

375

Light Scattering Investigations of Phase Transitions in Barium-Sodium  

Microsoft Academic Search

Barium sodium niobate, Ba_2NaNb _5O_{15} (BSN) possesses an incommensurate (IC) phase between an IC transition at T_1 = 300^circ C and a partial lock-in transition at T _{L} = 270^circ C. In addition, a few BSN crystals of the proper stoichiometry exhibit a reentrant phase transition at T_sp{1}{'} = 105 K to a phase with the same higher point group

William Franklin Oliver III

1988-01-01

376

Barium peritonitis: a rare complication of upper gastrointestinal contrast investigation.  

PubMed Central

Contrast examination of the gastrointestinal tract is rarely complicated by perforation. The colon and rectum are most commonly affected, with many perforations limited to the retroperitoneum. Generalised peritonitis is therefore rare, but is life-threatening and difficult to treat. We present two analogous cases in which extravasation of barium sulphate complicated contrast meal investigation. These cases illustrate important aspects in the management of this unusual occurrence. Images Figure

Karanikas, I. D.; Kakoulidis, D. D.; Gouvas, Z. T.; Hartley, J. E.; Koundourakis, S. S.

1997-01-01

377

Liberation of sulfate from sulfate esters by soils.  

PubMed

When incubated with acid, alkaline, and neutral soils, a variety of synthetic sulfate esters representing the various classes of these compounds was hydrolyzed by enzymes, probably of microbial origin. The appearance of sulfate in the soil water occurred immediately after introduction into the soils with some esters, whereas with others it occurred only after lag periods. Heat treatment destroyed the hydrolytic acitivity in the soils. The ester sulfate groups present in humic acid extracted from the soil appeared to be resistant to hydrolysis by a variety of sulfohydrolases extracted from bacteria and other organisms. PMID:938044

Houghton, C; Rose, R A

1976-06-01

378

Liberation of sulfate from sulfate esters by soils.  

PubMed Central

When incubated with acid, alkaline, and neutral soils, a variety of synthetic sulfate esters representing the various classes of these compounds was hydrolyzed by enzymes, probably of microbial origin. The appearance of sulfate in the soil water occurred immediately after introduction into the soils with some esters, whereas with others it occurred only after lag periods. Heat treatment destroyed the hydrolytic acitivity in the soils. The ester sulfate groups present in humic acid extracted from the soil appeared to be resistant to hydrolysis by a variety of sulfohydrolases extracted from bacteria and other organisms. Images

Houghton, C; Rose, R A

1976-01-01

379

Method of precipitating ADU  

Microsoft Academic Search

A process is disclosed for improving the quality of an ammonium diuranate (ADU) precipitate. Ammonium hydroxide is added to a solution of uranyl fluoride in the presence of a polymer such as polyacrylic acid, polyacrylonitrile, or polyacrylamide. The presence of the polymer reduces the particle size of the precipitate and increases its settling rate. A reduced particle size provides an

Chiang

1981-01-01

380

PRECIPITATION OF PROTACTINIUM  

DOEpatents

An lmprovement in the separation of protactinium from aqueous nitric acid solutions is described. 1t covers the use of lead dioxide and tin dioxide as carrier precipitates for the protactinium. In carrying out the process, divalent lead or divalent tin is addcd to the solution and oxidized, causing formation of a carrier precipitate of lead dioxide or stannic oxide, respectively.

Moore, R.L.

1958-07-15

381

Freezing precipitation in Canada  

Microsoft Academic Search

Renewed interest in freezing precipitation processes and their cause have resulted in a requirement for an updated, detailed climatology of freezing precipitation in Canada. Previous work in this area was very limited in terms of the period of record and the extent of the analysis.In this study national maps were prepared of occurrence frequencies of freezing rain, freezing drizzle and

R. A. Stuart; G. A. Isaac

1999-01-01

382

Atoms in crossed fields: calculations for barium and hydrogen  

NASA Astrophysics Data System (ADS)

A method previously developed by Halley et al for non-hydrogenic atoms in laboratory strength static electric and magnetic fields (treated separately, and in a parallel geometry combination) has been extended to also handle crossed fields. Stimulated by results from recent experiments by Connerade et al at Imperial College, London, we have used the method to calculate the crossed field 0953-4075/30/16/004/img6 and 0953-4075/30/16/004/img7 barium photoabsorption spectra measured in these experiments. The calculated results are found to be in excellent agreement with those from experiment. Moreover, calculation complementing experiment has allowed the experimental magnetic field strength to be identified to better than 0.3% and barium field-free quantum defects to be determined to better than 0.01% (modulo unity). The corresponding photoabsorption spectra have also been calculated for hydrogen. Comparing calculated spectra and wavefunctions for the two atoms has identified the non-hydrogenic behaviour of barium, especially at longer wavelengths, to be due to the anomalous spectral locations, at near-zero electric field, of a small number of `seed' states. These `seed' states remain in their anomalous locations but grow in oscillator strength as the electric field strength is increased, thus giving rise to significant, localized, non-hydrogenic photoabsorption features. For progressively shorter wavelengths we reach a point where `seed' states can no longer be identified, and a much more uniform distribution of oscillator strength in the spectrum results.

Rao, Jianguo; Taylor, K. T.

1997-08-01

383

Orbital barium CRRES injection - effective source of ionospheric wavelike disturbances  

NASA Astrophysics Data System (ADS)

Spectral analysis of artificial wavelike disturbances (WD) in ionospheric parameters is presented. The sources of WD are barium clouds injections in Combined Release and Radiation Effects Satellite (CRRES) perigee experiments. Plasma concentration pulsations are found in the ionospheric F2 layer maximum over Havana (Cuba) at distances 1500-2500 km from the barium injection. It was found that for the spectral component with 10 min period, the delay (relative to injection moment) corresponded to WD propagation velocity in 323-390 m/s band and depended on the specific injection conditions. It was shown that in every experiment the WD effective propagation velocity in the terminator region correlated with the sunlit part of the trajectory from the injection point to Havana. When comparing this WD type with WD's of other origins (from earthquakes, high-altitude explosions and solar terminator), it was shown that purposeful injection in the ionosphere of even a small barium quantity with orbital velocity in terminator region might be the effective means for generation or amplification of natural WD.

Ruzhin, Yu. Ya.; Oraevsky, V. N.; Depueva, A. Kh.; Perez, H.; Palasio, L.

384

Barium thiolates and selenolates: syntheses and structural principles.  

PubMed

The synthesis and structural characterization of a family of barium thiolates and selenolates is described. The thiolates were synthesized by metallation of thiols, the selenolates by reductive insertion of the metal into the selenium-selenium bond of diorganodiselenides. Both reaction sequences were carried out by using barium metal dissolved in ammonia; this afforded barium thiolates and selenolates in good yield and purity. The structural principles displayed in the target compounds span a wide range of solid-state formulations, including monomeric and dimeric species, and separated ion triples, namely [Ba(thf)4(SMes*)2] (1; Mes* = 2,4,6-tBU3C6H2), [Ba(thf)4(SeMes*)2] (2), [Ba([18]crown-6)(hmpa)2][(SeMes*)2] (3), the dimeric [(Ba(py)3(thf)(SeTrip)2)2] (4; py = pyridine, Trip = 2,4.6-iPr3C6H2), and [Ba([18]crown-6)(SeTrip)2] (5). The full range of association modes is completed by [Ba([18]crown-6)(hmpa)SMes*][SMes*] (6) communicated earlier by this group. In the solid state, this compound displays an intermediate ion coordination mode: one anion is bound to the metal, while the second one is unassociated. Together these compounds provide structural information about all three different association modes for alkaline earth metal derivatives. This collection of structural data allows important conclusions about the influence of solvation and ligation on structural trends. PMID:11151839

Ruhlandt-Senge, K; Englich, U

2000-11-17

385

The effect of acid rain and altitude on concentration, ? 34S, and ? 18O of sulfate in the water from Sudety Mountains, Poland  

Microsoft Academic Search

The analyses of sulfate content, ?34S and ?18O of dissolved sulfate, and ?18O of water were carried out in a 14 km2 crystalline massif located in the Sudety Mountains (SW Poland) to 1) assess the amount of the sulfate delivered to the surface and groundwater systems by modern atmospheric precipitation, 2) determine the effect of altitude on these parameters, and 3)

Anna Szynkiewicz; Magdalena Modelska; Mariusz Orion J?drysek; Maria Mastalerz

2008-01-01

386

CLOUD AND CHEMICAL PATHWAY CHARACTERIZATION OF THE NONLINEAR RESPONSE OF SULFUR DEPOSITION AND SULFATE AIR CONCENTRATIONS TO CHANGES IN SO2 EMISSIONS IN THE RADM  

EPA Science Inventory

The aqueous-phase chemistry that occurs in both precipitating and nonprecipitating clouds provides a major mechanism for the conversion of S02 to sulfate in the troposphere. ccording to the Regional Acid Deposition Model (RADM), cloud production of sulfate dominates over gas-phas...

387

Exopolymeric substances of sulfate-reducing bacteria: Interactions with calcium at alkaline pH and implication for formation of carbonate minerals  

Microsoft Academic Search

Sulfate-reducing bacteria (SRB) have been recognized as key players in the precipitation of calcium carbonate in lithifying microbial communities. These bacteria increase the alkalinity by reducing sulfate ions, and consuming organic acids. SRB also produce copious amounts of exopolymeric substances (EPS). All of these processes influence the morphology and mineralogy of the carbonate minerals. Interactions of EPS with metals, calcium

O. BRAISSANT; A. W. DECHO; C. DUPRAZ; C. GLUNK; K. M. PRZEKOP; P. T. VISSCHER

2007-01-01

388

Synthesis of barium titanate films by plasma electrolytic oxidation at room electrolyte temperature  

Microsoft Academic Search

Crystalline barium titanate films were directly synthesized onto Ti plates by plasma electrolytic oxidation at room temperature using barium acetate and 2 M NaOH as electrolytes. The effect of the concentration of barium acetate ranging from 0.05 M to 0.5 M on the synthesis of BaTiO3 was investigated. XRD results showed that the formation of BaTiO3 required a minimum of

Chu-Tsun Wu; Fu-Hsing Lu

2005-01-01

389

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

390

Determination of silicon, barium, and titanium in fresnoite single crystals and raw materials for them  

SciTech Connect

Single crystals of fresnoite show good electroptic parameters and high resistance to laser radiation, and are being examined for use in acoustoelectronics and optoelectronics. This paper investigates simple and reliable methods of determining silicon, barium, and titanium without preliminary separation. The authors examined the effects of large amounts of titanium and barium on the determination of silicon; it was found that titanium interferes. Barium does not interfere with the determination of silicon. Barium and titanium were determined by EDTA titration. The relative standard deviation in determining each of the elements did not exceed 6 x 10/sup -3/.

Sizonenko, N.T.; Egorova, L.A.; Gaiduk, O.V.; Khukhryanskii, A.K.

1985-09-01

391

Method for flue gas conditioning with the decomposition products of ammonium sulfate or ammonium bisulfate  

Microsoft Academic Search

This patent describes a method for conditioning flue gas containing suspended fly ash. It comprises: diverting a slipstream of flue gas from a main flue gas stream at a point upstream from an air preheater located directly upstream of an electrostatic precipitator; introducing an aqueous solution of ammonium sulfate or ammonium bisulfate into the diverted flue gas slipstream thereby effecting

R. F. Altman; J. P. Gooch; E. B. Dismukes; E. C. Jr. Landham

1989-01-01

392

LONG-RANGE TRANSPORT AND TRANSFORMATION OF SO2 AND SULFATE  

EPA Science Inventory

Technical descriptions and computer programs are presented for two models that calculate long-range transport, diffusion, transformation of SO2 to sulfate, and dry and precipitation deposition of initially emitted SO2. One model treats the mixing layer height as constant; the oth...

393

Reduction of Iron Oxides Enhanced by a Sulfate-Reducing Bacterium and Biogenic H2S  

Microsoft Academic Search

Interactions between bacteria and minerals at low temperatures often lead to accelerated alteration and transformation of mineral phases through dissolution and precipitation. Here we report the reductive dissolution of ferrihydrite, goethite, hematite, and magnetite by the sulfate-reducing bacterium Desulfovibrio desulfuricans strain G-20. The goal of this study was: (1) to investigate iron reduction by G-20 using iron as the sole

Yi-Liang Li; Hojatollah Vali; John Yang; Tommy J. Phelps; Chuanlun L. Zhang

2006-01-01

394

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

395

Diel cycles in dissolved barium, lead, iron, vanadium, and nitrite in a stream draining a former zinc smelter site near Hegeler, Illinois  

USGS Publications Warehouse

Diel variations in the concentrations of a number of constituents have the potential to substantially affect the appropriate sampling regimen in acidic streams. Samples taken once during the course of the day cannot adequately reflect diel variations in water quality and may result in an inaccurate understanding of biogeochemical processes, ecological conditions, and of the threat posed by the water to human health and the associated wildlife. Surface water and groundwater affected by acid drainage were sampled every 60 to 90. min over a 48-hour period at a former zinc smelter known as the Hegeler Zinc Superfund Site, near Hegeler, Illinois. Diel variations related to water quality in the aquifer were not observed in groundwater. Diel variations were observed in the temperature, pH, and concentration of dissolved oxygen, nitrite, barium, iron, lead, vanadium, and possibly uranium in surface water. Temperature, dissolved oxygen, nitrite, barium, lead, and uranium generally attained maximum values during the afternoon and minimum values during the night. Iron, vanadium, and pH generally attained minimum values during the afternoon and maximum values during the night. Concentrations of dissolved oxygen were affected by the intensity of photosynthetic activity and respiration, which are dependent upon insolation. Nitrite, an intermediary in many nitrogen reactions, may have been formed by the oxidation of ammonium by dissolved oxygen and converted to other nitrogen species as part of the decomposition of organic matter. The timing of the pH cycles was distinctly different from the cycles found in Midwestern alkaline streams and likely was the result of the photoreduction of Fe3+ to Fe 2+ and variations in the intensity of precipitation of hydrous ferric oxide minerals. Diel cycles of iron and vanadium also were primarily the result of variations in the intensity of precipitation of hydrous ferric oxide minerals. The diel variation in the concentrations of lead, uranium, and barium may have been affected by competition with Fe+2 for sorption sites on hydrous ferric oxide minerals. ?? 2010.

Kay, R. T.; Groschen, G. E.; Cygan, G.; Dupre, David, H. , D. H.

2011-01-01

396

Separation of lanthanum, hafnium, barium and radiotracers yttrium-88 and barium-133 using crystalline zirconium phosphate and phosphonate compounds as prospective materials for a Ra-223 radioisotope generator.  

PubMed

Crystalline hybrid organic/inorganic ion exchangers based on zirconium phosphate and phosphonate compounds were evaluated for application in radium-223 generator for radiopharmaceutical applications. Various compositions were synthesized and the selectivity of these materials was determined for inactive lanthanum, hafnium and barium, and radiotracers yttrium-88 and barium-133. The hybrid materials show very efficient lanthanum/barium separation; the response for zirconium phosphate was even better. A small-scale column loaded with pelletized zirconium phosphate compound demonstrated excellent retention of (88)Y and release of (133)Ba. PMID:21421323

Möller, Teresia; Bestaoui, Naima; Wierzbicki, Melissa; Adams, Todd; Clearfield, Abraham

2011-02-26

397

Sulfate decomposition by bacterial leaching  

Microsoft Academic Search

Sulfate disposal is the main problem of many industrial effluents, such as excess sulfuric acid, gypsum, coal desulfurization\\u000a byproducts, acid-mine waters, and general metallurgical effluents. It has been established that sulfate present in wastes\\u000a can be converted to elemental sulfur by bacterial mutualism. This study presents the results of an investigation of the industrial\\u000a feasibility of utilizing a biological system

Nuran Deveci; Cüneyt Göktug Delaloglu

1995-01-01

398

[Antiviral action of sulfated polysaccharides].  

PubMed

The literature data on the structure and biological spectrum of sulfated polysaccharides (fucoidans) from the sea brown algae are presented. The review includes the data on the experimental studies and the results of the author's researches on the sulfated polysaccharides inhibitory action on virus adsorption on eukaryotic cells. Mechanisms of the antiviral action of the fucoidans from the sea brown algae are discussed. PMID:19499720

Makarenkova, I D; Besednova, N N; Zaporozhets, T S

2009-01-01

399

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

2006-02-20

400

Acid Precipitation: A Bibliography.  

National Technical Information Service (NTIS)

This bibliography contains 3197 references to information on various aspects of acid precipitation that have been included in the Department of Energy's Energy Data Base through February 1983. The references cover research reports, journal articles, books...

P. S. Blackburn

1983-01-01

401

Cerium Oxalate Precipitation.  

National Technical Information Service (NTIS)

Cerium, a nonradioactive, common stand-in for plutonium in development work, has been used to simulate several plutonium precipitation processes at the Savannah River Laboratory. There are similarities between the plutonium trifluoride and the cerium oxal...

T. P. Chang

1987-01-01

402

PLUTONIUM PEROXIDE PRECIPITATION  

Microsoft Academic Search

Precipitation of the hexagonal structure of plutomium peroxide is an ; excellent concentration and purification step in plutouium metal preparation. ; Formation of an undesirable cubic structure is avoided by proper control of ; process variables. (auth);

J. A. Leary; A. N. Morgan; W. J. Maraman

1959-01-01

403

Porphyria Precipitated by Fasting.  

National Technical Information Service (NTIS)

Acute intermittent porphyria is associated with an increase of the rate controlling enzyme of porphyrin biosynthesis, delta-aminolevulinic acid synthetase. Several chemotherapeutic agents may induce a marked increase of this synthetase and precipitate the...

K. B. Knudsen M. Sparberg F. Lecocq

1968-01-01

404

PRECIPITATION OF NEPTUNIUM PEROXIDE  

Microsoft Academic Search

Optimum conditions were determined for the precipitation of ;\\u000a neptunium(IV) peroxide from nitric acid solutions. The results indicate that the ;\\u000a precipitation could be applied successfully on a plant scale. Data are presented ;\\u000a for the solubility of neptunium peroxide in solutions of nitric acid and hydrogen ;\\u000a peroxide. The solubility is less than 10⁻⁴M in 1.5 to 2.5M nitric

G. A. Burney; E. K. Dukes

2010-01-01

405

Participation of the Pennsylvania State University in the MAP3S precipitation chemistry network. Final report  

SciTech Connect

Precipitation in central Pennsylvania was collected for more than 14 years on behalf of the Multistate Atmospheric Power Production Pollution Study (MAP3S). The MAP3S protocol, based on the sampling of precipitation from individual meteorological events over a long period of time, has allowed both for the development of a chemical climatology of precipitation in the eastern region of the United States and for a vastly improved understanding of the atmospheric processes responsible for wet acidic deposition. The precipitation chemistry data from the Penn State MAP3S site provide evidence of links to the anthropogenic emissions of sulfur dioxide and oxidant precursors. There is now little doubt that the free acidity in the precipitation of the region is due to the presence of unneutralized sulfate in the aqueous phase. In the absence of significant sources of this sulfur species and in view of supplemental enrichment studies, it is concluded that the sulfate enters cloud and rain water primarily through the aqueous-phase oxidation of sulfur dioxide emitted into the air within the geographical region of deposition. Within the source region the local abundances of sulfur dioxide often exceed those of the oxidants, so the depositions of sulfate and free acidity tend to be modulated by the availability of the strong oxidants. As a consequence, the deposition of sulfate exhibits a very strong seasonal dependence and little response to changes in the emissions of sulfur dioxide.

Lamb, D.; de Pena, R.G.

1992-04-01

406

Participation of the Pennsylvania State University in the MAP3S precipitation chemistry network  

SciTech Connect

Precipitation in central Pennsylvania was collected for more than 14 years on behalf of the Multistate Atmospheric Power Production Pollution Study (MAP3S). The MAP3S protocol, based on the sampling of precipitation from individual meteorological events over a long period of time, has allowed both for the development of a chemical climatology of precipitation in the eastern region of the United States and for a vastly improved understanding of the atmospheric processes responsible for wet acidic deposition. The precipitation chemistry data from the Penn State MAP3S site provide evidence of links to the anthropogenic emissions of sulfur dioxide and oxidant precursors. There is now little doubt that the free acidity in the precipitation of the region is due to the presence of unneutralized sulfate in the aqueous phase. In the absence of significant sources of this sulfur species and in view of supplemental enrichment studies, it is concluded that the sulfate enters cloud and rain water primarily through the aqueous-phase oxidation of sulfur dioxide emitted into the air within the geographical region of deposition. Within the source region the local abundances of sulfur dioxide often exceed those of the oxidants, so the depositions of sulfate and free acidity tend to be modulated by the availability of the strong oxidants. As a consequence, the deposition of sulfate exhibits a very strong seasonal dependence and little response to changes in the emissions of sulfur dioxide.

Lamb, D.; de Pena, R.G.

1992-04-01

407

Participation of the Pennsylvania State University in the MAP3S precipitation chemistry network  

SciTech Connect

The Meteorology Department of the Pennsylvania State University collected precipitation in central Pennsylvania for more than 14 years on behalf of the Multistate Atmospheric Power Production Pollution Study (MAP3S). The MAP3S protocol, based on the sampling of precipitation from individual meteorological events over a long period of time, has allowed both for the development of a chemical climatology of precipitation in the eastern region of the United States and for a vastly improved understanding of the atmospheric processes responsible for wet acidic deposition. The precipitation chemistry data from the Penn State MAP3S site provide evidence of links to the anthropogenic emissions of sulfur dioxide and oxidant precursors. There is now little doubt that the free acidity in the precipitation of the region is due to the presence of unneutralized sulfate in the aqueous phase. In the absence of significant sources of this sulfur species and in view of supplemental enrichment studies, it is concluded that the sulfate enters cloud and rain water primarily through the aqueous-phase oxidation of sulfur dioxide emitted into the air within the geographical region of deposition. Within the source region the local abundances of sulfur dioxide often exceed those of the oxidants, so the depositions of sulfate and free acidity tend to be modulated by the availability of the strong oxidants. As a consequence, the deposition of sulfate exhibits a very strong seasonal dependence and little response to changes in the emissions of sulfur dioxide.

Lamb, D.; de Pena, R.G.

1991-04-01

408

Participation of the Pennsylvania State University in the MAP3S precipitation chemistry network. Final report  

SciTech Connect

The Meteorology Department of the Pennsylvania State University collected precipitation in central Pennsylvania for more than 14 years on behalf of the Multistate Atmospheric Power Production Pollution Study (MAP3S). The MAP3S protocol, based on the sampling of precipitation from individual meteorological events over a long period of time, has allowed both for the development of a chemical climatology of precipitation in the eastern region of the United States and for a vastly improved understanding of the atmospheric processes responsible for wet acidic deposition. The precipitation chemistry data from the Penn State MAP3S site provide evidence of links to the anthropogenic emissions of sulfur dioxide and oxidant precursors. There is now little doubt that the free acidity in the precipitation of the region is due to the presence of unneutralized sulfate in the aqueous phase. In the absence of significant sources of this sulfur species and in view of supplemental enrichment studies, it is concluded that the sulfate enters cloud and rain water primarily through the aqueous-phase oxidation of sulfur dioxide emitted into the air within the geographical region of deposition. Within the source region the local abundances of sulfur dioxide often exceed those of the oxidants, so the depositions of sulfate and free acidity tend to be modulated by the availability of the strong oxidants. As a consequence, the deposition of sulfate exhibits a very strong seasonal dependence and little response to changes in the emissions of sulfur dioxide.

Lamb, D.; de Pena, R.G.

1991-04-01

409

Composition and structure measurements in an ionospheric barium cloud. Final report  

SciTech Connect

A 48 kg barium payload was launched from Eglin Air Force Base, Florida on 12 December 1980 at 2311 GMT and detonated at 183.7 km. At 2342:50.25 GMT, a second rocket, instrumented with an ion mass spectrometer and pulsed plasma probes, was fired to traverse the barium cloud. Composition, ion density, and structure measurements were acquired up to 241.2 km in both the natural and disturbed ionosphere. The rocket penetrated the barium cloud between 147 and 184 km. In addition to the Ba+, Ba++ produced by H Lyman alpha ionization, and Ca+, an impurity in the barium were detected in the cloud. A peak barium ion concentration of about 6,000,000 ions cu cm was measured at 161 km where the ionospheric NO+ and O2+ ions were essentially eliminated by large recombination loss. The bottom side of the barium cloud had a relatively smooth structure while the top side showed significant density fluctuations. The first experimental evidence of a theoretically predicted E region 'image cloud' was found in the form of an enhanced NO+ layer just below the barium cloud. Unexplained wave-like density variations in O+, NO+, and O2(+) also were seen above the barium cloud to 195 km. A quantitative estimate of the outgassing water vapor concentrations near the payload's surface was made using the fast change transfer rate coefficient for O+ + H2O yields H2O+ + O that created the observed water vapor ions.

Narcisi, R.; Trzcinski, E.; Federico, G.; Wlodyka, L.; Bench, P.

1981-12-23

410

Primary lymphoma of the colon and rectum: CT and barium enema correlation  

Microsoft Academic Search

This paper presents the computed tomographic (CT) and barium enema (BE) findings in seven patients with proven primary lymphoma of the colon and rectum. CT and BE examination are complimentary studies in the evaluation of primary lymphoma of the colorectum, and certain relevant findings may be missed when radiographic evaluation does not include both modalities. Both CT and barium studies

Susan H. Wyatt; Elliot K. Fishman; Bronwyn Jones

1993-01-01

411

Rapid detection of myrosinase-producing fungi: a plate method based on opaque barium sulphate formation  

Microsoft Academic Search

A simple and rapid technique to assess the capability of fungi to produce myrosinase is reported. This was carried out by growing the tested fungi in sinigrin–barium agar plates. Strains capable of producing myrosinase were indicated by an opaque barium sulphate zone forming underneath and\\/or surrounding their colonies. This simple test has been confirmed by determination of myrosinase activity in

P. Sakorn; N. Rakariyatham; H. Niamsup; P. Nongkunsarn

2002-01-01

412

H? production in a small multicusp ion source with addition of barium  

Microsoft Academic Search

The effect on H? production by adding barium to a hydrogen discharge, in a small magnetically filtered multicusp ion source, has been investigated. It is found that the addition of barium can increase the H? output by a factor of 30. A strong dependence of H? output on the temperature of the ion source wall has also been observed.

S. R. Walther; K. N. Leung; W. B. Kunkel

1989-01-01

413

H - production in a small multicusp ion source with addition of barium  

Microsoft Academic Search

The effect on H⁻ production by adding barium to a hydrogen discharge, in a small magnetically filtered multicusp ion source, has been investigated. It is found that the addition of barium can increase the H⁻ output by a factor of 30. A strong dependence of H⁻ output on the temperature of the ion source wall has also been observed.

S. R. Walther; K. N. Leung; W. B. Kunkel

1989-01-01

414

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

415

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...

416

Epitaxial bismuth telluride layers grown on (111) barium fluoride substrates suitable for MQW-growth  

Microsoft Academic Search

Multi quantum wells and superlattices are discussed as suitable tools for increasing ZT. Best layer quality should be expected only for lattice matched growth. Therefore (111) barium fluoride should be most suitable compared to other common substrates like mica and sapphire, although up to now epitaxial growth of bismuth telluride on (111) barium fluoride with atomically flatness was not achieved.

J. Nurnus; H. Bottner; H. Beyer; A. Lambrecht

1999-01-01

417

Colonoscopy without premedication versus barium enema: a comparison of patient discomfort  

Microsoft Academic Search

Background: Colonoscopy is considered a painful procedure requiring routine intravenous sedation. We investigated whether unsedated colonoscopy causes more discomfort than barium enema. Methods: Procedure-related discomfort was determined in 100 consecutive patients undergoing colonoscopy without premedication and in an equal number of patients referred for sigmoidoscopy and barium enema. All patients underwent such examinations for the first time and had no

Volker F. Eckardt; Gerd Kanzler; Dieter Willems; Alexander J. Eckardt; Gudrun Bernhard

1996-01-01

418

Lack of effect of drinking water barium on cardiovascular risk factors  

SciTech Connect

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

Wones, R.G.; Stadler, B.L.; Frohman, L.A. (Univ. of Cincinnati College of Medicine, OH (USA))

1990-04-01

419

QUANTITATIVE RADIOCHEMICAL ANALYSIS BY ION EXCHANGE. V. CALCIUM, STRONTIUM, AND BARIUM  

Microsoft Academic Search

A procedure was developed for the separation of calcium, strontiums and ; barium from the rare earths and from each other. This is similar to the ion-; exchange method of Baerg and Bartholomew which elutes cerium, lanthanums ; strontiums and barium sequentially from a Dowex-50 Xl2, 87 deg C column using ; solutions of ammonium alpha -hydroxyisobutyrate. By lowering the

Wish

1959-01-01

420

Synthesis and properties of barium titanate solid solution thin films deposited on copper substrates  

Microsoft Academic Search

Barium titanate thin films were deposited via chemical solution deposition using a hybrid-chelate chemistry directly on copper foil substrates. A process was developed to crystallize and densify the ferroelectric films at 900°C by using a reductive atmosphere containing nitrogen, hydrogen, water vapor, and oxygen impurities such that film constituents were oxidized to form barium titanate and the foil substrate remained

Jon Fredrick Ihlefeld

2006-01-01

421

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...

422

Nanocrystalline structure and magnetic properties of barium ferrite particles prepared via glycine as a fuel  

Microsoft Academic Search

The barium ferrite particles were prepared using a self-propagating combustion method with glycine as a fuel. The process was investigated with differential scanning calorimeter and thermogravimetric analysis. The effects of the pH value of the precursor solution, the glycine dosage and calcination temperature on the morphology, the crystalline structure and the magnetic properties of the barium ferrite particles were studied

Jianxun Qiu; Le Liang; Mingyuan Gu

2005-01-01

423

Observation and theory of the barium releases from the CRRES satellite  

Microsoft Academic Search

The relationship between releases of barium from the NASA Combined Release and Radiation Effects Satellite (CRRES) and enhanced auroral activity is discussed with reference to observational data. Barium releases were conducted at a variety of altitudes and injection velocities, and plasma irregularities are reported as a result of the interactions. Auroral activity increased within 5 min of each release, and

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

1992-01-01

424

Acute barium toxicity from ingestion of “snake” fireworks  

Microsoft Academic Search

Introduction  Ingestion of fireworks has been infrequently reported in the medical literature. We describe a case of acute barium poisoning\\u000a following firework ingestion.\\u000a \\u000a \\u000a \\u000a Case Report  A 35-year-old male with a history of severe mental retardation presented with vomiting and diarrhea following ingestion of\\u000a 16 small fireworks (“color snakes” and “black snakes”). His condition rapidly deteriorated and he developed obtundation, wide\\u000a complex dysrhythmias,

Sean H. Rhyee; Kennon Heard

2009-01-01

425

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

426

Analysis of the sixth spectrum of barium: Ba VI  

NASA Astrophysics Data System (ADS)

The spectrum of barium was photographed in the 300 Å-1240 Å wavelength region on a 3-m normal incidence spectrograph at the Antigonish laboratory. The source used was a triggered spark. All five levels of the ground configuration 5s25p3 and 42 of 44 levels of the 5s5p4 + 5s25p25d + 5s25p26s configurations of Ba VI have been established. One hundred and twenty-seven lines have been classified. The parametric least-squaresfitted calculations involving configuration interaction amongst even parity configurations were carried out to interpret the observed spectrum satisfactorily.

Tauheed, A.; Joshi, Y. N.

1994-03-01

427

Agglomeration behavior of solid nickel on polycrystalline barium titanate  

SciTech Connect

This letter describes the phenomenon that takes place between nickel/barium titanate couples when heated under conditions employed in multilayer ceramic capacitor manufacturing practice: a 4hr, 1300°C isothermal anneal in 1% H2 – 99% N2. Dense, sputtered nickel films were observed to dewet the titanate and agglomerate into discrete or interconnected islands via a solid-state process. Up to a critical film thickness value of ~1.4?m, the degree of agglomeration was found to display an exponential dependence on the thickness of the original nickel film.

Weil, K. Scott; Mast, Eric S.; Sprenkle, Vince

2007-11-01

428

Nanodielectric system for cryogenic applications: Barium titanate filled polyvinyl alcohol  

SciTech Connect

In the current study the focus is on dielectric properties (as a function of frequency and temperature) of a polymeric composite system composed of polyvinyl alcohol and barium titanate nano powder. In the investigations, the temperature range is between 50-295 K, and the frequency range is between $20\\ \\hertz-1\\ \\mega\\hertz$. Polarization and conduction processes are investigated in the linear regime. Dielectric breakdown strengths of samples are also reported. The materials presented have potential to be implemented in cryogenic capacitor or field grading applications.

Tuncer, Enis [ORNL; Sauers, Isidor [ORNL; James, David Randy [ORNL; Ellis, Alvin R [ORNL; Duckworth, Robert C [ORNL

2008-01-01

429

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

430

The barium ion jet experiments of the Porcupine project  

NASA Astrophysics Data System (ADS)

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

Haerendel, G.

1980-06-01

431

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.

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

2012-01-01

432

High resolution imaging of barium ions and atoms near the sampling cone of an inductively coupled plasma mass spectrometer  

Microsoft Academic Search

Planar laser-induced fluorescence was used to map density distributions of ground state barium atoms, ground state barium ions, and excited-state barium ions in the region between the load coil and the sampling cone of an inductively coupled plasma mass spectrometer. The effects of power, nebulizer gas flow rate, and the addition of lithium to the sample on the distributions were

Andrew A. Mills; Jeffrey H. Macedone; Paul B. Farnsworth

2006-01-01

433

Recovery of Co Ions from Aqueous Solutions by Froth Flotation. Part II. CoS Precipitation  

Microsoft Academic Search

Cobalt ions have been recovered from aqueous solutions by dispersed-air flotation in acidic conditions. The preliminary step of precipitation as cobalt sulfide using Na2S is kinetically limited, with only approximately 70% of the cobalt ions being recovered. Recoveries increase considerably under alkaline conditions, where Co(OH)2 is also precipitated. Several collectors have been tested: cetyl trimethyl ammonium bromide, sodium dodecyl sulfate.

M. M. Koutlemani; P. Mavros; A. I. Zouboulis

1995-01-01

434

Fabrication of yttrium aluminum garnet transparent ceramics from yttria nanopowders synthesized by carbonate precipitation  

Microsoft Academic Search

Nanocrystalline yttria powders have been successfully synthesized by using yttrium nitrate as starting salt and ammonium hydrogen\\u000a carbonate as precipitant. It was found that a small amount of ammonia sulfate in the yttrium nitrate solution can effectively\\u000a reduce the agglomeration and the resultant powders display good dispersion. Pure cubic phase yttria powders were prepared\\u000a by calcining the precipitate at 1100 °C

Hua Gong; Dingyuan Tang; Hui Huang; Jan Ma

2009-01-01

435

Precipitation Composition in the Ohio River Valley: Spatial Variability and Temporal Trends  

Microsoft Academic Search

Sulfate (SO4\\u000a 2?), nitrate (NO3\\u000a ?) and ammonium (NH4\\u000a +) concentrations in precipitation as measured at NADP sites within the Ohio River Valley of the Midwestern USA between 1985\\u000a and 2002 are quantified and temporal trends attributed to changes\\/ variations in (i) the precipitation regime, (ii) emission\\u000a patterns and (iii) air mass trajectories. The results indicate that mean SO4\\u000a 2?

K. F. Kvale; S. C. Pryor

2006-01-01

436

Fabrication of barium/strontium carbonate coated amorphous carbon nanotubes as an improved field emitter  

NASA Astrophysics Data System (ADS)

Amorphous carbon nanotubes (aCNTs) were synthesized by a chemical reaction between ferrocene and ammonium chloride at a temperature ˜250 ?C in an air furnace. As-synthesized aCNTs were coated with the barium/strontium carbonate through a simple chemical process. The coating of barium/strontium carbonate was confirmed by a high resolution transmission electron microscopy, X-ray diffraction, and Fourier transformed infrared spectroscopy. Morphology of the as-prepared samples was studied by field emission scanning electron microscopy. Thermal gravimetric analysis showed that barium/strontium carbonate coated aCNTs are more stable than the pristine aCNTs. As-prepared barium/strontium carbonate coated aCNTs showed significantly improved field emission properties with a turn-on field as low as 2.5 V/?m. The variation of field emission characteristics of the barium/strontium carbonate coated aCNTs with interelectrode distances was also studied.

Maity, S.; Jha, A.; Das, N. S.; Chattopadhyay, K. K.

2013-02-01

437

Temperature dependence dielectric properties of modified barium titanate-PVB composites  

NASA Astrophysics Data System (ADS)

In this work, attempts are made to prepare ceramic polymer-composite followed by characterization of dielectric properties. The Barium Titanate ceramic powders are synthesized using the hydrothermal process. Silane treatment is carried out on Barium Titanate powder to increase its compatibility with polymer, followed with preparation of ceramic-polymer composite. Polyvinyl Butyral (PVB) is used as matrix for preparation of the composites and the concentration of Barium Titanate is increased from 60 to 90 wt%. Dielectric properties such as volume resistivity, dielectric constant, dissipation factor are evaluated. Results indicate that the dielectric constant and dissipation factor vary between 52 to 120 and 0.01 to 0.07; respectively as the relative ratio of polymer and silane modified Barium Titanate is varied. Specifically, at 90 wt% of silane modified Barium Titanate, the highest dielectric constant of 123 along with dissipation factor of 0.07 is obtained.

Joshi, N. J.; Rakshit, P. B.; Grewal, G. S.; Shrinet, V.; Pratap, A.

2013-06-01

438

METHOD OF FORMING PLUTONIUM-BEARING CARRIER PRECIPITATES AND WASHING SAME  

DOEpatents

An improvement of the lanthanum fluoride carrier precipitation process for the recovery of plutonium is presented. In this process the plutonium is first segregated in the LaF/su precipitate and this precipitate is later dissolved and the plutonium reprecipitated as the peroxide. It has been found that the loss of plutonium by its remaining in the supernatant liquid associated with the peroxide precipitate is greatly reduced if, before dissolution, the LaF/ sub 3/ precipitate is subjected to a novel washing step which constitutes the improvement of this patent. The step consists in intimately contactifng the LaF/ sub 3/ precipitate with a 4 to 10 percent solution of sodium hydrogen sulfate at a temperature between 10 and 95 deg C for 1/2 to 3 hours.

Faris, B.F.

1959-02-24

439

Effect of sulfide removal on sulfate reduction at pH 5 in a hydrogen fed gas-lift bioreactor.  

PubMed

Biotechnological treatment of sulfate- and metal-ionscontaining acidic wastewaters from mining and metallurgical activities utilizes sulfate-reducing bacteria to produce sulfide that can subsequently precipitate metal ions. Reducing sulfate at a low pH has several advantages above neutrophilic sulfate reduction. This study describes the effect of sulfide removal on the reactor performance and microbial community in a high-rate sulfidogenic gas-lift bioreactor fed with hydrogen at a controlled internal pH of 5. Under sulfide removal conditions, 99% of the sulfate was converted at a hydraulic retention time of 24 h, reaching a volumetric activity as high as 51 mmol sulfate/l/d. Under nonsulfide removal conditions, <25% of the sulfate was converted at a hydraulic retention time of 24 h reaching volumetric activities of <13mmol sulfate/l/d. The absence of sulfide removal at a hydraulic retention time of 24 h resulted in an average H2S concentration of 18.2 mM (584 mg S/l). The incomplete sulfate removal was probably due to sulfide inhibition. Molecular phylogenetic analysis identified 11 separate 16S rRNA bands under sulfide stripping conditions, whereas under nonsulfide removal conditions only 4 separate 16S rRNA bands were found. This shows that a less diverse population was found in the presence of a high sulfide concentration. PMID:19047826

Bijmans, Martijn F M; Dopson, Mark; Ennin, Frederick; Lens, Piet N L; Buisman, Cees J N

2008-11-01

440

Low-frequency Electrical Response to Microbial Induced Sulfide Precipitation  

SciTech Connect

We investigated the sensitivity of low-frequency electrical measurements to microbeinduced metal sulfide precipitation. Three identical sand-packed monitoring columns were used; a geochemical column, an electrical column and a control column. In the first experiment, continuous upward flow of nutrients and metals in solution was established in each column. Cells of Desulfovibrio vulgaris (D. vulgaris) were injected into the center of the geochemical and electrical columns. Geochemical sampling and post-experiment destructive analysis showed that microbial induced sulfate reduction led to metal precipitation on bacteria cells, forming motile biominerals. Precipitation initially occurred in the injection zone, followed by chemotactic migration of D. vulgaris and ultimate accumulation around the nutrient source at the column base.

Ntarlagiannis, Dimitrios; Williams, Kenneth H.; Slater, Lee D.; Hubbard, Susan S.

2005-11-19

441

Can barium enema indicate when colonoscopy will be difficult?  

PubMed

The barium enemas of 48 consecutive patients, who were technically difficult to intubate at colonoscopy, were compared to those of 46 patients who were not. Measurements were taken of colonic length and mobility, and an assessment made of diverticular disease. Rectosigmoid length (mean difficult group = 61 cm, mean control = 54 cm, P = 0.01) and total colonic length (mean difficult group = 157 cm, mean control = 140 cm, P < 0.0001) were greater in the difficult colonoscopy group as were transverse colon mobility (mean difficult group = 10 cm, mean control = 7 cm, P = 0.003) or redundancy (transverse colon reaching the true pelvis on the erect film); 65% difficult group vs 17% control group, P < 0.0001. The presence of moderate or severe diverticular disease was also greater in the difficult (23%) compared to the control (4%) group, P = 0.02. When available, assessment of a previous barium enema is a useful guide to probable technical difficulty of colonscopy. It may allow appropriate allocation of potentially difficult cases to specialist endoscopy lists. PMID:7743720

Saunders, B P; Halligan, S; Jobling, C; Fukumoto, M; Moussa, M E; Williams, C B; Bartram, C I

1995-05-01

442

Indentation size effect in barium titanate with spherical tipped nanoindenters  

NASA Astrophysics Data System (ADS)

Nanoindentation tests in an 90°-ac-domain area of an {001} orientated barium titanate single crystal were performed using four different indenters (two with cube corner and two with spherical shape) with tip radii from 61 nm to 1.9 ?m. Extensive calibrations of the tips on fused quartz and sapphire defined the penetration depth range for approximately spherical contact prior to indentation of barium titanate (BaTiO3). The measured elastic modulus is independent of the different indenters. The measurements showed plastic deformation after ``pop-in''. The calculated mean pressure remained constant for each indenter, but clearly depends upon the indenter radius. The indenter radius dependence of the hardness support the concept of ``geometrically necessary dislocations'', proposed by W. D. Nix and H. Gao [J. Mech. Phys. Sol., 46, 411 (1998)] and its extension to spherical tipped indenters [J. G. Swadener, E. P. George, G. M. Pharr, J. Mech. Phys. Solids, 50, 681 (2002)]. The results show this concept fits the data generated with indenter radii which are at least an order of magnitude lower than investigated by Swadener. Furthermore, the results agree with estimates of the statistically stored dislocation density determined for BaTiO3.

Scholz, T.; Muñoz-Saldaña, J.; Swain, M. V.; Schneider, G. A.

2006-02-01

443

Proton trapping in yttrium-doped barium zirconate  

NASA Astrophysics Data System (ADS)

The environmental benefits of fuel cells have been increasingly appreciated in recent years. Among candidate electrolytes for solid-oxide fuel cells, yttrium-doped barium zirconate has garnered attention because of its high proton conductivity, particularly in the intermediate-temperature region targeted for cost-effective solid-oxide fuel cell operation, and its excellent chemical stability. However, fundamental questions surrounding the defect chemistry and macroscopic proton transport mechanism of this material remain, especially in regard to the possible role of proton trapping. Here we show, through a combined thermogravimetric and a.c. impedance study, that macroscopic proton transport in yttrium-doped barium zirconate is limited by proton–dopant association (proton trapping). Protons must overcome the association energy, 29?kJ?mol?1, as well as the general activation energy, 16?kJ?mol?1, to achieve long-range transport. Proton nuclear magnetic resonance studies show the presence of two types of proton environment above room temperature, reflecting differences in proton–dopant configurations. This insight motivates efforts to identify suitable alternative dopants with reduced association energies as a route to higher conductivities.

Yamazaki, Yoshihiro; Blanc, Frédéric; Okuyama, Yuji; Buannic, Lucienne; Lucio-Vega, Juan C.; Grey, Clare P.; Haile, Sossina M.

2013-07-01

444

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

PubMed

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

2013-06-28

445

FORMATION OF URANIUM PRECIPITATES  

DOEpatents

A method is described for precipitation of uranium peroxide from uranium- containing solutions so as to obtain larger aggregates which facilitates washings decantations filtrations centrifugations and the like. The desired larger aggregate form is obtained by maintaining the pH of the solution in the approximate range of 1 to 3 and the temperature at about 25 deg C or below while carrytng out the precipitation. Then prior to removal of the precipitate a surface active sulfonated bicarboxyacids such as di-octyl sodium sulfo-succinates is incorporated in an anount of the order of 0.01 to 0.05 percent by weights and the slurry is allowed to ripen for about one-half hour at a temperatare below 10 deg C.

Googin, J.M. Jr.

1959-03-17

446

URANIUM PRECIPITATION PROCESS  

DOEpatents

A method for the recovery of uranium from sulfuric acid solutions is described. In the present process, sulfuric acid is added to the uranium bearing solution to bring the pH to between 1 and 1.8, preferably to about 1.4, and aluminum metal is then used as a reducing agent to convert hexavalent uranium to the tetravalent state. As the reaction proceeds, the pH rises amd a selective precipitation of uranium occurs resulting in a high grade precipitate. This process is an improvement over the process using metallic iron, in that metallic aluminum reacts less readily than metallic iron with sulfuric acid, thus avoiding consumption of the reducing agent and a raising of the pH without accomplishing the desired reduction of the hexavalent uranium in the solution. Another disadvantage to the use of iron is that positive ferric ions will precipitate with negative phosphate and arsenate ions at the pH range employed.

Thunaes, A.; Brown, E.A.; Smith, H.W.; Simard, R.

1957-12-01

447

Sulfate deposition to surface waters  

SciTech Connect

Critical loads are the highest deposition of strong acid anions in surface waters that will not cause harmful biological effects on populations, such as declines in or extinctions of fish. Our analysis focuses on sulfate deposition because in glaciated regions sulfate is conservative in soils, whereas nitrate in biologically cycled. Sulfate also is the dominant anion in acidic deposition and in most acidic lakes. This analysis, represents the first evaluation of certain data available from Norway and the eastern United States, with an emphasis on the data from Scandinavia. The concept of dose-response is widely used in connection with water pollution. Any lake system subjected to an external dose of pollutants will have an internal resistance (or buffer capacity) to the change. The response of the lake system will depend on the relative magnitudes of the dose and the resistance parameters.

Henriksen, A.; Brakke, D.F.

1988-01-01

448

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

449

Effects of different fabrication techniques on the yttrium-barium-copper oxide high-temperature superconductor. Master's thesis  

SciTech Connect

This study examines how several different parameters were changed in the yttrium-barium-copper oxide superconductor when the fabrication techniques were altered by using different barium precursors, including barium peroxide and barium carbonate; sintering at different temperatures, including 850, 900, and 950 C; and annealing in an above ambient oxygen environment. Twelve different pellets were fabricated, and measurements were taken on them which included density, x-ray diffraction, critical temperature, critical current density, and magnetic susceptibility. Results showed that the barium perioxide derived samples had higher densities, better critical current densities and lower resistivities in the normal state.

Rhea, P.A.

1988-12-01

450

Mineralogy and Organic Geochemistry of Acid Sulfate Environments from Valles Caldera, New Mexico: Habitability, Weathering and Biosignatures  

NASA Astrophysics Data System (ADS)

We report on the mineralogy, organic preservation potential and habitability of sulfate deposits in acid sulfate volcanic settings at Valles Caldera, New Mexico. Fumaroles and acidic springs are potential analogs for aqueous environments on Mars and may offer insights into habitability of sulfate deposits such as those at Meridiani Planum. Sulfates recently detected on Mars are posited to have formed from fluids derived from basaltic weathering and igneous volatile input, ultimately precipitating from acidic brines subjected to desiccation and freeze-thaw cycles (McClennan and Grotzinger, 2008). Key issues concerning martian sulfate deposits are their relationship to aqueous clay deposits, and whether or not specific sulfates deposits represent former habitable environments (see Soderblum and Bell, 2008; Tosca et al., 2008). Modern terrestrial volcanic fumaroles and hot springs precipitate various Ca-, Mg- and Fe- sulfates along with clays, and can help clarify whether certain acid sulfate mineral assemblages reflect habitable environments. Valles caldera is a resurgent caldera last active in the Pleistocene (1.4 - 1.0 Ma) that hosts several active fumaroles and over 40 geothermal exploration wells (see Goff, 2009). Fumaroles and associated mudpots and springs at Valles range from pH < 1 to 3, and affect argillic alteration upon rhylolitic tuffs and sedimentary deposits (Charles et al., 1986). We identified assemblages containing gypsum, quartz, Al-sulfates, elemental sulfur, clays and other minerals using XRD and SEM-EDS. Our previous research has shown that sulfates from different marine depositional environments display textural and morphological traits that are indicative of biological influence, or specific conditions in the depositional environments (Vogel et al., 2009). Gypsum crystals that develop in the presence of microbial biofilms in marine environments may have distorted crystal morphologies, biofilm - associated dissolution features, and accessory carbonate minerals. Gypsum from Valles Caldera fumaroles develops in the absence of microbial biofilms and differs from biologically influenced marine gypsum in terms of is highly prismatic morphology, lack of texture, and association with clays, and other sulfates. Studies of Valles gypsum crystals therefore support the uniqueness of the putative morphological biosignatures in marine gypsum. We also assayed organic matter from fumarole encrustations to understand how low pH and sulfate content may discriminate against or enhance preservation of specific classes of organic compounds in acid sulfate environments. Similar to gypsiferous marine environments, organics are characterized by abundant organosulfur complexes. Long chain alkanes (> nC22) are abundant from acid sulfate environments. As with hypersaline marine depositional environments, sulfidation appears to be a major diagenetic pathway for organic matter in acid sulfate environments.

Vogel, M. B.; Des Marais, D. J.; Jahnke, L. L.; Kubo, M.

2009-12-01

451

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

452

Static and fatigue mechanical behavior of bone cement with elevated barium sulfate content for treatment of vertebral compression fractures  

Microsoft Academic Search

The use of bone cement to treat vertebral compression fractures in a percutaneous manner requires placement of the cement under fluoroscopic image guidance. To enhance visualization of the flow during injection and to monitor and prevent leakage beyond the confines of the vertebral body, the orthopedic community has described increasing the amount of radiopacifier in the bone cement. In this

S. M. Kurtz; M. L. Villarraga; K. Zhao; A. A. Edidin

2005-01-01

453

Long-term retention of /sup 133/Ba in the rat trachea following local administration as barium sulfate particles  

SciTech Connect

Long-term retention of /sup 133/Ba in the trachea from intratracheally administered BaSO/sub 4/ particles was determined by both serial sacrifice and external scanning methods up to 6 months after injection. The amount of /sup 133/Ba retained 1 week after injection in the caudal region of the trachea, where the tip of the cannula had been at injection, was 0.41% of the initial dose. Thereafter the /sup 133/Ba was cleared exponentially with a mean half-time of 88 days, as determined from the autopsy samples. The cranial region of the trachea, including the site of the tracheostomy, contained /sup 133/Ba at 10 times the level in the caudal region 1 week after injection and was cleared with a half-time of 66 days. These clearance rates were confirmed by repeated external scanning over the trachea. The 133Ba was drained to the lymph nodes not only in the thoracic cavity but also in the cervical region, suggesting the possibility of lymphatic drainage from the trachea to the cervical lymph nodes.

Takahashi, S.; Patrick, G.

1987-06-01

454

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...

455

Orogenic propagating precipitation systems  

NASA Astrophysics Data System (ADS)

Organized propagating systems in the lee of mountains make an important contribution to convective precipitation in midlatitudes (e.g., US during the warm season) and in the tropics throughout the year. These systems display a high degree of variability in regard to the thermodynamic state (i.e., temperature and moisture distribution) and kinetic state (i.e., vertical shear) of the atmosphere. However, propagating precipitation systems are absent from climate models and are inadequately represented in global numerical weather prediction (NWP) models, if they are present at all. The reason is simple. Firstly, traditional cumulus parameterizations do not represent interactions between latent heating, rain evaporation and wind-shear which are fundamental to the mesoscale convective dynamics. Secondly, the spatial resolution of climate models is too coarse to permit explicit mesoscale convective organization. This has practical implications for quantitative precipitation prediction and fundamental implications for the Earth's water cycle and its variability. This talk will describe issues regarding the parameterization of organized convection for climate models, its explicit representation by cloud-system resolving models (CRMs, and hybrid representation for high-resolution NWP models. Also described will be new methodologies for representing propagating precipitation systems in climate models: i)superparameterization whereby traditional convective parameterization is replaced by CRMs; ii) hybrid parametric representation of stratiform heating, mesoscale downdrafts, and organized momentum transport associated with propagating systems.

Moncrieff, Mitchell; Pritchard, Mike

2010-05-01

456

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

SciTech Connect

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

Jin Yi [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials, Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Zhu Yihua [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials, Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China)], E-mail: yhzhu@ecust.edu.cn; Yang Xiaoling [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials, Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Li Chunzhong [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials, Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Zhou Jinghong [UNILAB, State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237 (China)

2007-01-15

457

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...

458

Long term effects of phosphorus precipitations with alum in hypereutrophic Lake Süsser See (Germany)  

Microsoft Academic Search

Precipitation and inactivation of phosphorus (P) by the addition of aluminum (Al) is a widely applied lake restoration measure. Many studies about short-term effects are reported, but little is known about long-term effects. To reduce this lack of knowledge we investigated the German hardwater lake, Süsser See, which was treated almost annually from 1977 to 1992 with aluminum sulfate (alum).

Jörg Lewandowski; Inke Schauser; Michael Hupfer

2003-01-01

459

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...

460

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

Lazaroff, Norman; Sigal, Warren; Wasserman, Andrew

1982-01-01

461

Classification of chondroitin sulfate A, chondroitin sulfate C, glucosamine hydrochloride and glucosamine 6 sulfate using chemometric techniques  

Microsoft Academic Search

Chondroitin sulfate A, chondroitin sulfate C, glucosamine hydrochloride and glucosamine sulfate are natural products that are becoming increasingly popular in the treatment of arthritis. They belong to a class of compounds known as glycosaminoglycans (GAGs). They are available over the counter as nutritional supplements. However, increasing use has led to increasing scrutiny of the quality of products on the market.

M. Foot; M. Mulholland

2005-01-01

462

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

463

Status of Copper Sulfate - 2010  

Technology Transfer Automated Retrieval System (TEKTRAN)

This is brief overview of the Technical Sections completed and being worked on for the New Animal Drug Application (NADA) for copper sulfate. Initial Label Claim (Ich on catfish): 1) Human Food Safety - Complete for all fin fish - February 2004. This includes human intestinal microflora issues,...

464

Natural Relationships among Sulfate-Reducing Eubacteria.  

National Technical Information Service (NTIS)

Phylogenetic relationships among 20 nonsporeforming and two endospore-forming species of sulfate-reducing eubacteria were inferred from comparative 16S rRNA sequencing. All genera of mesophilic sulfate-reducing eubacteria except the new genus Desulfomicro...

R. Devereux M. Delaney F. Widdel D. A. Stahl

1989-01-01

465

21 CFR 184.1315 - Ferrous sulfate.  

Code of Federal Regulations, 2013 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...

2013-04-01

466

21 CFR 182.8997 - Zinc sulfate.  

Code of Federal Regulations, 2013 CFR

...HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients § 182.8997 Zinc sulfate. (a) Product. Zinc sulfate. (b) Conditions of use. This substance is...

2013-04-01

467

21 CFR 582.5315 - Ferrous sulfate.  

Code of Federal Regulations, 2013 CFR

...AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5315 Ferrous sulfate. (a) Product. Ferrous sulfate. (b)...

2013-04-01

468

21 CFR 582.5443 - Magnesium sulfate.  

Code of Federal Regulations, 2013 CFR

...AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5443 Magnesium sulfate. (a) Product. Magnesium sulfate. (b)...

2013-04-01

469

21 CFR 582.5230 - Calcium sulfate.  

Code of Federal Regulations, 2013 CFR

...AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5230 Calcium sulfate. (a) Product. Calcium sulfate. (b)...

2013-04-01

470

21 CFR 582.5997 - Zinc sulfate.  

Code of Federal Regulations, 2013 CFR

...AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5997 Zinc sulfate. (a) Product. Zinc sulfate. (b) Conditions of...

2013-04-01

471

Active ingredient: Abacavir Sulfate and Lamivudine Form ...  

Center for Drug Evaluation (CDER)

Text VersionContains Nonbinding Recommendations Draft Guidance on Abacavir Sulfate and Lamivudine ... Active ingredient: Abacavir Sulfate and Lamivudine ... More results from www.fda.gov/downloads/drugs/guidancecomplianceregulatoryinformation

472

Infrared Spectroscopy of Amorphous Sulfate Phases  

NASA Astrophysics Data System (ADS)

Stability experiments have indicated that amorphous sulfate phases may be important constituents of martian surface materials. IR spectral properties of X-ray amorphous Mg- and Fe-sulfate phases are described and compared with their crystalline counterparts.

Rogers, A. D.; Reeder, R. J.; Glotch, T. D.

2009-03-01

473

Stability Constants for Sulfate Complexation of Yttrium and the Rare Earth Elements  

NASA Astrophysics Data System (ADS)

In natural waters, yttrium and the rare earth elements (YREE) are mostly complexed with inorganic anions such as carbonate and chloride. YREE complexation with sulfate is minor (<5%) in seawater and generally negligible in fresh waters, yet it can be quite important in situations where oxidation of pyrite leads to high dissolved sulfate concentrations. The development of a consensus pattern of stability constants for YREE monosulfato-complexes has a quite convoluted history. It is based on a 1974 'compilation' that was derived from a much older, somewhat questionable, dataset, by adding interpolations and omitting a few elements. During subsequent transcriptions, some errors were introduced and the omitted data were interpolated rather than replaced with the original values. All this has resulted in a consensus pattern that is essentially flat, without any structure or fractionation between light and heavy REE. It is widely quoted and has been used to argue that sulfate complexation does not cause YREE fractionation. Conversely, flat YREE patterns in natural waters have been taken as evidence for substantial complexation of the YREE with sulfate. We have taken a new approach to measuring the stability constants of all YREE monosulfato-complexes with the greatest possible precision. Stability constants were determined by comparing the solubility of barium sulfate in YREE chloride solutions and in an ammonium chloride reference solution, all at the ionic strength of seawater. The reference solution and solutions of individual YREE chlorides were equilibrated with a small amount of high purity barium sulfate at t = 25°C for at least one week. The equilibrated solutions were then filtered and analyzed for concentrations of YREE and Ba (ICP-MS), chloride and sulfate (ion chromatography), and pH (glass electrode). A simple model was used to determine the stability constants from these measurements. Averaged results from four experiments, two with and two without added sulfate, have standard deviations of 0.03 log units or less. Within this precision, the pattern of stability constants is not flat, as has been assumed, but has a very distinct shape. The pattern is nearly flat from La to Gd, possibly with a slight maximum at Eu. From Gd to Lu it shows a gradual and almost linear decrease, with the stability constant of Lu being more than 0.2 log units below that of La. The stability constant of Y is close to that of Er. Our pattern is in broad agreement with several careful earlier studies that have been largely ignored in the recent literature. Comparison with the substantial body of existing work also indicates that our stability constants are well within the published range for individual YREE. This revised pattern may have significant consequences for the interpretation of YREE patterns in high-sulfate environments such as runoff from mine tailings and certain groundwaters.

Schijf, J.; Byrne, R. H.

2002-12-01

474

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 mixtur