Sample records for barium sulfate precipitation

  1. Effect of gas and liquid flowrates on the size distribution of barium sulfate nanoparticles precipitated in a two phase flow capillary microreactor

    Microsoft Academic Search

    D. Jeevarathinam; A. K. Gupta; B. Pitchumani; Ratan Mohan

    2011-01-01

    Production of fine particles by precipitation is a relatively simple process but the control of product particle size distribution can be difficult. In recent years microreactors are being seen as effective devices to achieve this aim and in that the two-phase flow microreactor is a promising alternative. In the present work, fine (nano\\/micro) particles of barium sulfate have been produced

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

    USGS Publications Warehouse

    Hannon, Janet E.; Bohlke, Johnkarl F.; Mroczkowski, Stanley J.

    2008-01-01

    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.

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

    USGS Publications Warehouse

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

    2008-01-01

    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.

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

    PubMed

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

    2009-06-01

    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

  5. Laboratory and prediction of barium sulfate scaling at high-barium formation water

    Microsoft Academic Search

    Amer Badr BinMerdhah; Abu Azam Mohd Yassin; Mazen Ahmed Muherei

    2010-01-01

    Scale formation in surface and subsurface oil and gas production equipment has been recognized to be a major operational problem. It has been also recognized as major causes of formation damage either in injection or producing wells. This study was conducted to investigate the permeability reduction caused by deposition of barium sulfate in sandstone cores from mixing of injected seawater

  6. 59 FR- Barium Sulfate; Toxic Chemical Release Reporting; Community Right-To-Know

    Federal Register 2010, 2011, 2012, 2013, 2014

    1994-06-28

    ...of the statement regarding the water solubility of barium sulfate and how it relates...with the commenters that, at the water solubility of 2.4 mg/ L (2.4 ppm) at 25...However, due to its limited water solubility, barium sulfate is not expected...

  7. Solubility and solubility constant of barium sulfate in aqueous sodium sulfate solutions between 0 and 80°C

    Microsoft Academic Search

    Chengfa Jiang

    1996-01-01

    The solubilities of barium sulfate in aqueous solutions of sodium sulfate were studied at ionic strengths from 0.0005 to 0.02 mol-kg-1 and at 0, 20, 40, 60, and 80°C. The solubility data were used to calculate the solubility constants using an extrapolation method. The solubility constant obtained were in good agreement with literature data. The mean activity coefficients of barium

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

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

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

  9. 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,...

  10. Application of an intensified narrow channel reactor to the aqueous phase precipitation of barium sulphate

    Microsoft Academic Search

    E. D. McCarthy; W. A. E. Dunk; K. V. K. Boodhoo

    2007-01-01

    A homogeneous liquid phase reaction between barium chloride (BaCl2) and sodium sulphate (Na2SO4) was conducted in a narrow channel reactor to produce barium sulphate (BaSO4) precipitate. The effects of channel dimensions and channel residence times on crystal size, crystal size distribution, nucleation rates, crystal morphology and conversion of reactants were investigated at different levels of reactant supersaturation ratio. Our results

  11. EPR dosimetric properties of nano-barium sulfate

    NASA Astrophysics Data System (ADS)

    Aboelezz, E.; Hassan, G. M.; Sharaf, M. A.; El-Khodary, A.

    2015-01-01

    Nano/micro BaSO4 were prepared through the co-precipitation method to measure ionizing radiation doses using electron paramagnetic resonance (EPR). The nano-BaSO4 sample was characterized using X-ray diffraction (XRD), and transmission electron microscopy (TEM) techniques. The dose response and fading properties of nano- and micro-phase BaSO4 were compared in EPR spectra. The prepared nano- and micro-BaSO4 samples have the same hole and electron centers, which may be attributed to SO4- and SO3-, respectively. The dosimetric signals for prepared nano- and micro-BaSO4 have spectroscopic splitting factor (g) with values 2.0025±0.0006 and 2.0027±0.0006, respectively. The nanocrystalline sample has a linear ?-ray dose response over the range 0.4 Gy-1 kGy. The performance parameters which including detection limit and critical level calculated from weighted and unweighted least-squares fitting. The sensitivity of nano-BaSO4 to ?-ray is one and a half times more than alanine. The lifetime and activation energy for nano-BaSO4 were estimated by conducting a thermal stability study, and were 5.7±1.1×104 years and 0.73±0.14 eV, respectively. The combined and expanded uncertainties accompanying measurements were ±3.89% and ±7.78%, respectively.

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

    NASA Technical Reports Server (NTRS)

    Zaplatynsky, I.

    1979-01-01

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

  13. Ethanol-sensing characteristics of barium stannate prepared by chemical precipitation

    Microsoft Academic Search

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

    2000-01-01

    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

  14. Oilfield scales: controls on precipitation and crystal morphology of barite (barium sulphate)

    NASA Astrophysics Data System (ADS)

    Stark, A. I. R.; Wogelius, R. A.; Vaughan, D. J.

    2003-04-01

    The precipitation and subsequent build up of barite (barium sulphate) inside extraction tubing presents a costly problem for off shore oil wells which use seawater to mobilize oil during hydrocarbon recovery. Mixing of reservoir formation water containing Ba2+ ions and seawater containing SO_42- ions results in barite precipitation within the reservoir well-bore region and piping. Great effort has been expended in designing strategies to minimize scale formation but details of the reaction mechanism and sensitivity to thermodynamic variables are poorly constrained. Furthermore, few detailed studies have been carried out under simulated field conditions. Hence an experimental programme was designed to study barite formation under environmentally relevant conditions with control of several system variables during the precipitation reaction. Synthetic sea-water and formation-water brines containing sodium sulphate and barium chloride, respectively, were mixed to induce BaSO_4 precipitation. Experiments were carried out at high temperature (100^oC) and high pressure (500 bars) in double rocking autoclave bombs. Barite formation as a function of the addition of calcium, magnesium, and a generic phosphonate based scale inhibitor was investigated whilst maintaining constant pH, temperature and ionic strength (0.5159). Additional experiments were performed at ambient conditions for comparison. Data concerning nucleation, growth rates, and crystal morphology were obtained. ICP-AES data from the supernatant product solutions showed considerable variation in quantity of barium sulphate precipitated as a function of the listed experimental variables. For example, ESEM analysis of barium sulphate crystals showed a dramatic shift in crystal habit from the typical tabular habit produced in control experiments; experiments performed in the presence of foreign cations produced more equant crystals, while those experiments completed in the presence of the phosphonate scale inhibitor produced precipitates with distorted anhedral shapes. Based on these preliminary results, further experiments which monitor rate and morphology as a function of Ba/Ca ratio, ionic strength, and ion activity product for barite will also be completed.

  15. Aqueous hafnium sulfate chemistry: structures of crystalline precipitates.

    PubMed

    Kalaji, Ali; Soderholm, L

    2014-10-20

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

  16. Sulfate-reducing bacteria release barium and radium from naturally occurring radioactive material in oil-field barite

    USGS Publications Warehouse

    Phillips, E.J.P.; Landa, E.R.; Kraemer, T.; Zielinski, R.

    2001-01-01

    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 226 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 bacteria Desulfovibrio sp., Str LZKI, isolated from an oil-field brine pond. However, Ba release was not stoichiometric with sulfide production in oil-field samples, and <0.1% of the Ba was released. Potential for the release of 226Ra was demonstrated, and the 226 Ra release associated with sulfate-reducing activity was predictable from the amount of Ba released. As with Ba, only a fraction of the 226Ra expected from the amount of sulfide produced was released, and most of the Ra remained associated with the solid material.

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

    PubMed

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

    2010-01-01

    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

  18. X-ray Induced Luminescence Spectroscopy of Samarium Doped Barium Sulfate Prepared by Sintering Method

    NASA Astrophysics Data System (ADS)

    Kumeda, T.; Maeda, K.; Shirano, Y.; Fujiwara, K.; Sakai, K.; Ikari, T.

    2015-06-01

    X-ray induced luminescence (XL) properties of phosphor materials made of samarium doped barium sulfate have been investigated. The samples were prepared by sintering method heated at 900-1250 °C for 3 hours in air from the mixture of BaSO4 and Sm2O3. The concentration of Sm were prepared from 0.01-6 at.%. In as-prepared sample, the Sm3+ was detected by photoluminescence (PL). The PL intensity is maximum about 2 at.% with Sm, and then starts decreasing. The PL intensity showed concentration quenching. The XL observed Sm2+ and Sm3+ ions. The XL was shown from the sample sintered up to 1200 °C. The XL intensity increased with Sm concentration up to 1 at.%. The intensity was almost constant larger than 1 at.% Sm. These concentration dependences is different since the X-ray energy absorbed to the host material at once, and the energy transferred to both Sm3+ and Sm2+ ions. Sm doped BaSO4 is found a host for XL phosphor materials.

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

    SciTech Connect

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

    2010-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  1. Application of an intensified narrow channel reactor to the aqueous phase precipitation of barium sulphate.

    PubMed

    McCarthy, E D; Dunk, W A E; Boodhoo, K V K

    2007-01-01

    A homogeneous liquid phase reaction between barium chloride (BaCl(2)) and sodium sulphate (Na(2)SO(4)) was conducted in a narrow channel reactor to produce barium sulphate (BaSO(4)) precipitate. The effects of channel dimensions and channel residence times on crystal size, crystal size distribution, nucleation rates, crystal morphology and conversion of reactants were investigated at different levels of reactant supersaturation ratio. Our results indicate that the smallest particle sizes are favoured when supersaturation ratios and channel velocities are high. The minimum average particle diameter observed was approximately 0.2 microm in a channel of hydraulic diameter 0.5 mm and length 20 cm at an initial supersaturation ratio of 4483 (0.1 M), which correspond to conditions giving rise to the highest nucleation rates. It has also been observed that particle size depends on the conversion to product, the smallest particles being formed when conversion lies within the range of 30 to 40%. Conversions in excess of 60% have been reached but there is a detectable limiting effect with increased supersaturation and reduced residence times. Experiments conducted at similar levels of supersaturation under stirred tank conditions showed that particle size was consistently larger and particle size distribution was much broader than that achieved in the narrow channel reactor. Scanning electron microscopy (SEM) images of the crystals formed in the narrow channels show that spherical particles dominate in the smallest channels at high velocities whilst coarse, tabular crystals are obtained in the larger channels. Greater tendency to agglomerate is also observed at high supersaturation ratios, after one minute of reaction. PMID:17064716

  2. Use of 24 kHz ultrasound to improve sulfate precipitation from wastewater.

    PubMed

    Davies, Lisa A; Dargue, Andrew; Dean, John R; Deary, Michael E

    2015-03-01

    Elevated sulfate concentrations in industrial effluent can lead to a number of significant problems, the most serious of which is the corrosion of concrete sewers as a result of hydrogen sulfide induced biogenic sulfuric acid attack; hydrogen sulfide can also create odor nuisance problems. The most common treatment process for sulfate removal from wastewaters is to precipitate it as gypsum using lime addition. Nevertheless, meeting discharge consent limits for sulfate can often present practical challenges due to the solubility of gypsum and so there is a need to investigate technological solutions that might provide for more consistent sulfate removal. This paper reports on the application of ultrasound during the sulfate precipitation process. We show that with as little as 10 s sonication at 24 kHz, significant increases in the rate of sulfate precipitation are observed. Particle size analysis, pH profiles and SEM micrographs, suggest that the likely mode of action is disaggregation of the calcium hydroxide particles, giving a greater solid-liquid interface, thus resulting in a faster dissolution rate and more readily available calcium ions. A range of experimental variables are studied, including the duration and power of sonication, as well as initial sulfate concentration and the effect of changing the time at which sonication is applied. For both sonicated and non-sonicated samples, precipitation commences almost immediately that the lime is added and so induction time is not an issue in this system. PMID:25218769

  3. THE EFFECT OF SULFATE ION ON THE CRYSTAL SIZE OF PRECIPITATED RARE EARTH OXALATES

    Microsoft Academic Search

    A. Glasner; M. Steinberg; E. Levy

    1959-01-01

    In separating rare earths from other cations in the form of insoluble ; oxalatess it was found that well grown crystals were precipitated from solutions ; due to the effect of the sulfate ion. lt is pointed out that the precipitate from ; HNOâ solution is a collection of aggregates of small crystals, while those ; obtained from the sulfuric

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

    EPA Science Inventory

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

  5. Spontaneous precipitation of calcium carbonate in the presence of chondroitin sulfate

    NASA Astrophysics Data System (ADS)

    Manoli, F.; Dalas, E.

    2000-08-01

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

  6. Evaluation of Radiation Dose Reduction during CT Scans Using Oxide Bismuth and Nano-Barium Sulfate Shields

    E-print Network

    Seoung, Youl-Hun

    2015-01-01

    The purpose of the present study was to evaluate radiation dose reduction and image quality during CT scanning by using a new dose reduction fiber sheet (DRFS) with commercially available bismuth shields. These DRFS were composed of nano-barium sulfate (BaSO4), filling the gaps left by the large oxide bismuth (Bi2O3) particle sizes. The radiation dose was measured five times at directionss of 12 o'clock from the center of the polymethyl methacrylate (PMMA) head phantom to calculate an average value using a CT ionization chamber. The image quality measured CT transverse images of the PMMA head phantom depending on X-ray tube voltages and the type of shielding. Two regions of interest in CT transverse images were chosen from the right and left areas under the surface of the PMMA head phantom and from ion chamber holes located at directions of 12 o'clock from the center of the PMMA head phantom. The results of this study showed that the new DRFS shields could reduce dosages to 15.61%, 23.05%, and 22.71% more in ...

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

    PubMed

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

    2006-11-01

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

  8. Sulfate adsorption and surface precipitation on a volcanic ash soil (allophanic andisol).

    PubMed

    Ishiguro, Munehide; Makino, Tomoyuki; Hattori, Yasunobu

    2006-08-15

    Sulfate strongly adsorbs on metal oxides and soils with variable charges. However, its surface precipitation has not been clearly evaluated and its adsorption mechanism has been in dispute. In the present study, an allophanic andisol, a typical volcanic ash soil having both negative and positive variable charges, was used to identify the adsorption mechanism of sulfate. Sulfate adsorption isotherms were obtained by a batch method at pH values of 4, 5, 6, and 7 in a wide range of concentrations in an Na-H-SO(4)-OH system. Theoretical isotherms were applied to the measured values for the evaluation. The surface precipitation was detected by the measured adsorption isotherms, and the BET isotherm confirmed the presence of multilayer adsorption. Stronger and weaker adsorption sites were suggested by using the Langmuir isotherm for the monolayer adsorption. The adsorption energies obtained from the Langmuir equation and recent spectroscopic analysis suggested that the stronger adsorption corresponded to an inner-sphere surface complex and that the weaker adsorption corresponded to outer-sphere surface complexation. The BET and Langmuir equations showed three types of adsorption mechanisms for the sulfate adsorption on the soil. PMID:16750540

  9. Proteomic analysis of Helicobacter pylori cellular proteins fractionated by ammonium sulfate precipitation.

    PubMed

    Park, Jeong-Won; Lee, Seung-Gyu; Song, Jae-Young; Joo, Jung-Soo; Chung, Mi-Ja; Kim, Sam-Cheol; Youn, Hee-Shang; Kang, Hyung-Lyun; Baik, Seung-Chul; Lee, Woo-Kon; Cho, Myung-Je; Rhee, Kwang-Ho

    2008-07-01

    Among 1590 ORFs in the Helicobacter pylori genome, >250 have been identified as authentic genes by proteomic analysis. Low-abundance proteins need to be enriched to a minimal amount for MALDI-TOF analysis and salt precipitation has generally been used for protein enrichment. Here, a whole-cell extract of H. pylori strain 26695 was subjected to protein fractionation with stepwise concentrations of ammonium sulfate and the proteins were displayed by 2-DE. The protein spots were quantified using PDQUEST software and identified by peptide fingerprinting. The 2-DE profiles and intensities of individual protein spots differed among the protein fractions. Out of the 98 identified proteins, 61 were found in the stepwise ammonium sulfate fractions but not in the whole-cell extract. Out of these, 37 proteins, including KdsA, were found exclusively in a single fraction. In contrast, GroEL, UreA, UreB, TrxA, NapA, and FldA were ubiquitously present in all fractions. Iron-containing proteins such as NapA, SodB, CeuE, and Pfr were found predominantly in the 100% saturated ammonium sulfate precipitate. Additionally, 29 proteins were newly identified in this study. These data will facilitate the preparation of significant H. pylori proteins, as well as provide information about low-abundance proteins. PMID:18546177

  10. Precipitation method for barium metaborate (BaB{sub 2}O{sub 4}) synthesis from borax solution

    SciTech Connect

    Ak?ener, Eymen; Figen, Aysel Kantürk; Pi?kin, Sabriye [Yildiz Technical University, Chem. Eng. Dept., Davutpasa Campus, 34210, Istanbul (Turkey)

    2013-12-16

    In this study, barium metaborate (BaB{sub 2}O{sub 4}, BMB) synthesis from the borax solution was carried out. BMB currently is used in production of ceramic glazes, luminophors, oxide cathodes as well as additives to pigments for aqueous emulsion paints and also ??BaB{sub 2}O{sub 4} single crystals are the best candidate for fabrication of solid-state UV lasers operating at a wavelength of 200 nm due to excellent nonlinear optical properties. In the present study, synthesis was carried out from the borax solution (Na{sub 2}B{sub 4}O{sub 7?}10H{sub 2}O, BDH) and barium chloride (BaCI{sub 2?}2H{sub 2}O, Ba) in the glass-batch reactor with stirring. The effect of, times (5-15 min), molar ratio [stoich.ration (1.0:2.0), 1.25:2.0, 1.5:2.0, 2.5:2:0, 3.0:2.0, 3.5:2.0,4.0:2.0, 5.0:2.0] and also crystallization time (2-6 hour) on the BMB yield (%) was investigated at 80 °C reaction temperature. It is found that, BMB precipitation synthesis with 90 % yield can be performed from 0.50 molar ration (BDH:Ba), under 80 °C, 15 minute, and 6 hours crystallization time. The structural properties of BMB powders were characterized by using XRD, FT-IR and DTA-TG instrumental analysis technique.

  11. Centrifugal precipitation chromatography: principle, apparatus, and optimization of key parameters for protein fractionation by ammonium sulfate precipitation.

    PubMed

    Ito, Y

    2000-01-01

    A novel chromatographic system introduced here internally generates a concentration gradient of ammonium sulfate (AS) through a long separation channel under a centrifugal force field. Protein samples are exposed to a gradually increasing AS concentration and precipitated along the channel. Then, chromatographic elution is initiated by gradually decreasing the AS concentration in the gradient which causes the proteins to repeat dissolution and precipitation through the channel. Consequently, they are eluted out in the order of their solubility in the AS solution. The separation column consists of a pair of disks equipped with mutually mirror-imaged spiral grooves. A dialysis membrane is sandwiched between the disks to form two identical channels partitioned by the membrane. The disk assembly is mounted on the sealless continuous-flow centrifuge. When a concentrated AS solution is eluted through one channel and water through the other channel in an opposite direction, an exponential AS gradient is formed through the water channel. A series of basic experiments was performed to study the rates of AS transfer and osmosis through the membrane, and the operational parameters including elution time, revolution speed, inclination of gradient, and sample size were optimized using stable protein samples. Preliminary applications were successful in purification of monoclonal antibody from cell culture supernatant and an affinity separation of recombinant ketosteroid isomerase from a crude Escherichia coli lysate. PMID:10610699

  12. Biodegradation of BTEX and Other Petroleum Hydrocarbons by Enhanced and Controlled Sulfate Reduction

    SciTech Connect

    Song Jin

    2007-07-01

    High concentrations of sulfide in the groundwater at a field site near South Lovedale, OK, were inhibiting sulfate reducing bacteria (SRB) that are known to degrade contaminants including benzene, toluene, ethylbenzene, and m+p-xylenes (BTEX). Microcosms were established in the laboratory using groundwater and sediment collected from the field site and amended with various nutrient, substrate, and inhibitor treatments. All microcosms were initially amended with FeCl{sub 2} to induce FeS precipitation and, thereby, reduce sulfide concentrations. Complete removal of BTEX was observed within 39 days in treatments with various combinations of nutrient and substrate amendments. Results indicate that elevated concentration of sulfide is a limiting factor to BTEX biodegradation at this site, and that treating the groundwater with FeCl{sub 2} is an effective remedy to facilitate and enhance BTEX degradation by the indigenous SRB population. On another site in Moore, OK, studies were conducted to investigate barium in the groundwater. BTEX biodegradation by SRB is suspected to mobilize barium from its precipitants in groundwater. Data from microcosms demonstrated instantaneous precipitation of barium when sulfate was added; however, barium was detected redissolving for a short period and precipitating eventually, when active sulfate reduction was occurring and BTEX was degraded through the process. SEM elemental spectra of the evolved show that sulfur was not present, which may exclude BaSO{sub 4} and BaS as a possible precipitates. The XRD analysis suggests that barium probably ended in BaS complexing with other amorphous species. Results from this study suggest that SRB may be able to use the sulfate from barite (BaSO{sub 4}) as an electron acceptor, resulting in the release of free barium ions (Ba{sup 2+}), and re-precipitate it in BaS, which exposes more toxicity to human and ecological health.

  13. Evidence for Aqueously Precipitated Sulfates in Northeast Meridiani Using THEMIS and TES Data

    NASA Technical Reports Server (NTRS)

    Lane, Melissa D.

    2005-01-01

    Recently aqueously deposited sulfate-rich bedrock was found at the MER-B Meridiani landing site [1]. Additional sulfate was observed from orbit by the Mars Express OMEGA instrument [2]. In this work, I present midinfrared spectral evidence (using THEMIS and TES) for sulfate in and around a channel deposit that lies to the northeast of the hematite- strewn plains of Meridiani at approx.2degN, 1degW (Fig. 1).

  14. Selective Precipitation and Purification of Monovalent Proteins Using Oligovalent Ligands and Ammonium Sulfate

    E-print Network

    Weitz, David

    Selective Precipitation and Purification of Monovalent Proteins Using Oligovalent Ligands and purification of a monovalent protein (carbonic anhydrase is used as a demonstration) from cellular lysate using to predict protein solubility in an experimental context,2 the purification of proteins by precipitation

  15. Metabolic Engineering of an Aerobic Sulfate Reduction Pathway and Its Application to Precipitation of Cadmium on the Cell Surface

    Microsoft Academic Search

    CLIFFORD L. WANG; PRIYA D. MARATUKULAM; AMY M. LUM; DOUGLAS S. CLARK; J. D. Keasling

    2000-01-01

    The conversion of sulfate to an excess of free sulfide requires stringent reductive conditions. Dissimilatory sulfate reduction is used in nature by sulfate-reducing bacteria for respiration and results in the conversion of sulfate to sulfide. However, this dissimilatory sulfate reduction pathway is inhibited by oxygen and is thus limited to anaerobic environments. As an alternative, we have metabolically engineered a

  16. Protamine sulfate precipitation method depletes abundant plant seed-storage proteins: A case study on legume plants.

    PubMed

    Kim, Yu Ji; Wang, Yiming; Gupta, Ravi; Kim, So Wun; Min, Chul Woo; Kim, Yong Chul; Park, Ki Hun; Agrawal, Ganesh Kumar; Rakwal, Randeep; Choung, Myoung-Gun; Kang, Kyu Young; Kim, Sun Tae

    2015-05-01

    Depletion of abundant proteins is one of the effective ways to improve detection and identification of low-abundance proteins. Our previous study showed that protamine sulfate precipitation (PSP) method can deplete abundant ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) from leaf proteins and is suitable for their in-depth proteome investigation. In this study, we provide evidence that the PSP method can also be effectively used for depletion of abundant seed-storage proteins (SSPs) from the total seed proteins of diverse legume plants including soybean, broad bean, pea, wild soybean, and peanut. The 0.05% protamine sulfate (PS) was sufficient to deplete major SSPs from all legumes tested except for peanut where 0.1% PS was required. SDS-PAGE, Western blotting and 2DE analyses of PS-treated soybean and peanut seed proteins showed enriched spots in PS-supernatant than total proteins. Coefficient of variation percentage (%CV) and principal component analysis of 2DE spots support the reproducibility, suitability, and efficacy of the PSP method for quantitative and comparative seed proteome analysis. MALDI-TOF-TOF successfully identified some protein spots from soybean and peanut. Hence, this simple, reproducible, economical PSP method has a broader application in depleting plant abundant proteins including SSPs in addition to RuBisCO, allowing discussion for comprehensive proteome establishment and parallel comparative studies in plants. PMID:25641780

  17. 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 ...

  18. Trends in cation, nitrogen, sulfate and hydrogen ion concentrations in precipitation in the United States

    E-print Network

    Kurapov, Alexander

    reductions in base cation inputs in precipitation could lessen the effect of air pollution control that although the overall efforts of developed countries to reduce air pollution and acid rain by the mid among Euro- pean countries and the United States. We also expected that control of particulate versus

  19. Dissolution-precipitation processes in tank experiments for testing numerical models for reactive transport calculations: Experiments and modelling

    NASA Astrophysics Data System (ADS)

    Poonoosamy, Jenna; Kosakowski, Georg; Van Loon, Luc R.; Mäder, Urs

    2015-06-01

    In the context of testing reactive transport codes and their underlying conceptual models, a simple 2D reactive transport experiment was developed. The aim was to use simple chemistry and design a reproducible and fast to conduct experiment, which is flexible enough to include several process couplings: advective-diffusive transport of solutes, effect of liquid phase density on advective transport, and kinetically controlled dissolution/precipitation reactions causing porosity changes. A small tank was filled with a reactive layer of strontium sulfate (SrSO4) of two different grain sizes, sandwiched between two layers of essentially non-reacting quartz sand (SiO2). A highly concentrated solution of barium chloride was injected to create an asymmetric flow field. Once the barium chloride reached the reactive layer, it forced the transformation of strontium sulfate into barium sulfate (BaSO4). Due to the higher molar volume of barium sulfate, its precipitation caused a decrease of porosity and lowered the permeability. Changes in the flow field were observed with help of dye tracer tests. The experiments were modelled using the reactive transport code OpenGeosys-GEM. Tests with non-reactive tracers performed prior to barium chloride injection, as well as the density-driven flow (due to the high concentration of barium chloride solution), could be well reproduced by the numerical model. To reproduce the mineral bulk transformation with time, two populations of strontium sulfate grains with different kinetic rates of dissolution were applied. However, a default porosity permeability relationship was unable to account for measured pressure changes. Post mortem analysis of the strontium sulfate reactive medium provided useful information on the chemical and structural changes occurring at the pore scale at the interface that were considered in our model to reproduce the pressure evolution with time.

  20. Dissolution-precipitation processes in tank experiments for testing numerical models for reactive transport calculations: Experiments and modelling.

    PubMed

    Poonoosamy, Jenna; Kosakowski, Georg; Van Loon, Luc R; Mäder, Urs

    2015-01-01

    In the context of testing reactive transport codes and their underlying conceptual models, a simple 2D reactive transport experiment was developed. The aim was to use simple chemistry and design a reproducible and fast to conduct experiment, which is flexible enough to include several process couplings: advective-diffusive transport of solutes, effect of liquid phase density on advective transport, and kinetically controlled dissolution/precipitation reactions causing porosity changes. A small tank was filled with a reactive layer of strontium sulfate (SrSO4) of two different grain sizes, sandwiched between two layers of essentially non-reacting quartz sand (SiO2). A highly concentrated solution of barium chloride was injected to create an asymmetric flow field. Once the barium chloride reached the reactive layer, it forced the transformation of strontium sulfate into barium sulfate (BaSO4). Due to the higher molar volume of barium sulfate, its precipitation caused a decrease of porosity and lowered the permeability. Changes in the flow field were observed with help of dye tracer tests. The experiments were modelled using the reactive transport code OpenGeosys-GEM. Tests with non-reactive tracers performed prior to barium chloride injection, as well as the density-driven flow (due to the high concentration of barium chloride solution), could be well reproduced by the numerical model. To reproduce the mineral bulk transformation with time, two populations of strontium sulfate grains with different kinetic rates of dissolution were applied. However, a default porosity permeability relationship was unable to account for measured pressure changes. Post mortem analysis of the strontium sulfate reactive medium provided useful information on the chemical and structural changes occurring at the pore scale at the interface that were considered in our model to reproduce the pressure evolution with time. PMID:25805363

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

    PubMed

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

    2011-04-15

    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

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

    NASA Astrophysics Data System (ADS)

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

    2010-05-01

    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.

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

    SciTech Connect

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

    1996-08-01

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

  4. Studies of aged OH-Al solutions using kinetics of Al-ferron reactions and sulfate precipitation

    Microsoft Academic Search

    P. P. Tsai; P. H. Hsu

    2009-01-01

    A series of OH-Al solutions (0.02M in Al, NaOH\\/Al molar ratio = 1, slow neutralization) aged from 10 d to 55 months were all clear and had similar pH values and monomeric Al concentrations but reacted differently with sodium sulfate and ferron. The addition of sodium sulfate yielded three kinds of basic aluminum sulfates: tetrahedral crystals of composition Na\\/sub 0.08\\/Al(OH)\\/sub

  5. Evaluation of feed COD\\/sulfate ratio as a control criterion for the biological hydrogen sulfide production and lead precipitation

    Microsoft Academic Search

    Antonio Velasco; Martha Ram ´ õrez; Tania Volke-Sep ´ ulveda; Armando Gonzalez-S; Sergio Revah

    The ability of sulfate-reducing bacteria to produce hydrogen sulfide and the high affinity of sulfide to react with divalent metallic cations represent an excellent option to remove heavy metals from wastewater. Different parameters have been proposed to control the hydrogen sulfide production by anaerobic bacteria, such as the organic and sulfate loading rates and the feed COD\\/SO42? ratio. This work

  6. Extraction and characterization of lignin from oil palm biomass via ionic liquid dissolution and non-toxic aluminium potassium sulfate dodecahydrate precipitation processes.

    PubMed

    Mohtar, S S; Tengku Malim Busu, T N Z; Md Noor, A M; Shaari, N; Yusoff, N A; Bustam Khalil, M A; Abdul Mutalib, M I; Mat, H B

    2015-09-01

    The objective of this study is to extract and characterize lignin from oil palm biomass (OPB) by dissolution in 1-butyl-3-methylimidazolium chloride ([bmim][Cl]), followed by the lignin extraction through the CO2 gas purging prior to addition of aluminum potassium sulfate dodecahydrate (AlK(SO4)2·12H2O). The lignin yield, YL (%wt.) was found to be dependent of the types of OPB observed for all precipitation methods used. The lignin recovery, RL (%wt.) obtained from CO2-AlK(SO4)2·12H2O precipitation was, however dependent on the types of OPB, which contradicted to that of the acidified H2SO4 and HCl solutions of pH 0.7 and 2 precipitations. Only about 54% of lignin was recovered from the OPB. The FTIR results indicate that the monodispersed lignin was successfully extracted from the OPT, OPF and OPEFB having a molecular weight (MW) of 1331, 1263 and 1473g/mol, and degradation temperature of 215, 207.5 and 272°C, respectively. PMID:26038325

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

    USGS Publications Warehouse

    Szabo, B. J.; Joensuu, O.

    1967-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Bibi, Irshad; Singh, Balwant; Silvester, Ewen

    2011-11-01

    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.

  9. Radioactive mineral spring precipitates, their analytical and statistical data and the uranium connection

    USGS Publications Warehouse

    Cadigan, R.A.; Felmlee, J.K.

    1982-01-01

    Major radioactive mineral springs are probably related to deep zones of active metamorphism in areas of orogenic tectonism. The most common precipitate is travertine, a chemically precipitated rock composed chiefly of calcium carbonate, but also containing other minerals. The mineral springs are surface manifestations of hydrothermal conduit systems which extend downward many kilometers to hot source rocks. Conduits are kept open by fluid pressure exerted by carbon dioxide-charged waters rising to the surface propelled by heat and gas (CO2 and steam) pressure. On reaching the surface, the dissolved carbon dioxide is released from solution, and calcium carbonate is precipitated. Springs also contain sulfur species (for example, H2S and HS-), and radon, helium and methane as entrained or dissolved gases. The HS- ion can react to form hydrogen sulfide gas, sulfate salts, and native sulfur. Chemical salts and native sulfur precipitate at the surface. The sulfur may partly oxidize to produce detectable sulfur dioxide gas. Radioactivity is due to the presence of radium-226, radon-222, radium-228, and radon-220, and other daughter products of uranium-238 and thorium-232. Uranium and thorium are not present in economically significant amounts in most radioactive spring precipitates. Most radium is coprecipitated at the surface with barite. Barite (barium sulfate) forms in the barium-containing spring water as a product of the oxidation of sulfur species to sulfate ions. The relatively insoluble barium sulfate precipitates and removes much of the radium from solution. Radium coprecipitates to a lesser extent with manganese-barium- and iron-oxy hydroxides. R-mode factor analysis of abundances of elements suggests that 65 percent of the variance of the different elements is affected by seven factors interpreted as follows: (1) Silica and silicate contamination and precipitation; (2) Carbonate travertine precipitation; (3) Radium coprecipitation; (4) Evaporite precipitation; (5) Hydrous limonite precipitation and coprecipitated elements including uranium; (6) Rare earth elements deposited with detrital contamination (?); (7) Metal carbonate adsorption and precipitation. Economically recoverable minerals occurring at some localities in spring precipitates are ores of iron, manganese, sulfur, tungsten and barium and ornamental travertine. Continental radioactive mineral springs occur in areas of crustal thickening caused by overthrusting of crustal plates, and intrusion and metamorphism. Sedimentary rocks on the lower plate are trapped between the plates and form a zone of metamorphism. Connate waters, carbonate rocks and organic-carbon-bearing rocks react to extreme pressure and temperature to produce carbon dioxide, and steam. Fractures are forced open by gas and fluid pressures. Deep-circulating meteoric waters then come in contact with the reactive products, and a hydrothermal cell forms. When hot mineral-charged waters reach the surface they form the familiar hot mineral springs. Hot springs also occur in relation to igneous intrusive action or volcanism both of which may be products of the crustal plate overthrusting. Uranium and thorium in the sedimentary rocks undergoing metamorphism are sometimes mobilized, but mobilization is generally restricted to an acid hydrothermal environment; much is redeposited in favorable environments in the metamorphosed sediments. Radium and radon, which are highly mobile in both acid and alkaline aqueous media move upward into the hydrothermal cell and to the surface.

  10. 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

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

    2006-01-01

    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

  11. Current perspectives in colon radiography: the postendoscopy and postbiopsy barium enema.

    PubMed

    Lappas, J C; Maglinte, D D

    1985-01-01

    Controversy prevails regarding the same-day performance of barium enema examinations and endoscopy. Concerns focus upon the diagnostic quality of the postendoscopy barium enema and the risk of perforation if colorectal biopsy is performed during the endoscopy. Results of a study of 295 patients support that rigid or fiberoptic sigmoidoscopy can be performed the same day as single- or double-contrast barium enemas without adversely affecting the quality or interpretation of the barium examination. Animal studies suggest that a barium enema may be performed safely immediately after a superficial biopsy of a nondiseased colon and 6 days after a deep biopsy. Barium sulfate appears to have no deleterious effect on the healing of colorectal biopsy sites. These findings have important implications when considering health care logistics and cost containment. PMID:3896653

  12. Glucosamine sulfate

    MedlinePLUS

    ... Sulphate, Glucosamine Sulphate KCl, Glucosamine-6-Phosphate, GS, Mono-Sulfated Saccharide, Poly-(1->3)-N-Acetyl-2- ... Beta-D-Glucopyranurosyl-4-(or 6-) Sul, Saccharide Mono-Sulfaté, Saccharide Sulfaté, Sulfate de Glucosamine, Sulfate de ...

  13. Isotopic Zonation Within Sulfate Evaporite Mineral Crystals Reveal Quantitative Paleoenvironment Details

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

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

  14. Barium bright and heavy

    NASA Astrophysics Data System (ADS)

    Fromm, Katharina M.

    2013-02-01

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

  15. Electron donors for biological sulfate reduction

    Microsoft Academic Search

    Warounsak Liamleam; Ajit P. Annachhatre

    2007-01-01

    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

  16. Determination of sulfates in diesel particulates

    SciTech Connect

    Schuetzle, D.; Skewes, L.M.; Fisher, G.E.; Levine, S.P.; Gorse, R.A. Jr.

    1981-05-01

    Analytical techniques for the determination of total sulfates in diesel particulates are described utilizing the techniques of total combustion/nondispersive infrared (NDIR) detection and modified extraction/barium perchlorate-thorin titration (BPT). The combustion technique utilizes a commercially available sulfur analyzer (LECO-IR32) that requires less than 15 min for triplicate analysis and has a precision and accuracy of better than +- 5% for filter samples containing from 100 to 10,000 ..mu..g of sulfate. The combustion technique measures soluble and insoluble sulfate such as BaSO/sub 4/ and is not affected by the presence of large quantities of carbon in the particulate sample. The extraction efficiency for sulfates in diesel particulates using standard procedures was found to average 67% for samples containing only trace quantities of anions and 59% for samples containing stoichiometric levels of barium. These procedures have been modified to include ultrasonication with 2-proponal/water in order to overcome the problem of incomplete sulfate extraction. Extracted sulfate samples are then analyzed by using the BPT method. The extraction/BPT method showed an average recovery of 1.02 +- 0.12 (1 sigma) when compared to the combustion technique. ESCA studies showed that the chemical state of the surface sulfur species for the diesel particulates average 93 +- 3% sulfate and 7 +- 3% elemental sulfur.

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

    ERIC Educational Resources Information Center

    Hazen, Jeffery L.; Cleary, David A.

    2014-01-01

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

  18. Semiconducting barium titanate

    Microsoft Academic Search

    W. Heywang

    1971-01-01

    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

  19. Silicosis in barium miners.

    PubMed Central

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

    1986-01-01

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

  20. Properties of Semiconductive Barium Titanates

    Microsoft Academic Search

    Osamu Saburi

    1959-01-01

    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.

  1. Barium Vanadate Microspheres

    NASA Astrophysics Data System (ADS)

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

    2009-11-01

    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.

  2. An Inhibitor of the ?PKC Interaction with the d Subunit of F1Fo ATP Synthase Reduces Cardiac Troponin I Release from Ischemic Rat Hearts: Utility of a Novel Ammonium Sulfate Precipitation Technique

    PubMed Central

    Ogbi, Mourad; Obi, Ijeoma; Johnson, John A.

    2013-01-01

    We have previously reported protection against hypoxic injury by a cell-permeable, mitochondrially-targeted ?PKC-d subunit of F1Fo ATPase (dF1Fo) interaction inhibitor [NH2-YGRKKRRQRRRMLA TRALSLIGKRAISTSVCAGRKLALKTIDWVSFDYKDDDDK-COOH] in neonatal cardiac myo-cytes. In the present work we demonstrate the partitioning of this peptide to the inner membrane and matrix of mitochondria when it is perfused into isolated rat hearts. We also used ammonium sulfate ((NH4)2SO4) and chloroform/methanol precipitation of heart effluents to demonstrate reduced card-iac troponin I (cTnI) release from ischemic rat hearts perfused with this inhibitor. 50% (NH4)2SO4 saturation of perfusates collected from Langendorff rat heart preparations optimally precipitated cTnI, allowing its detection in Western blots. In hearts receiving 20 min of ischemia followed by 30, or 60 min of reperfusion, the Mean±S.E. (n?=?5) percentage of maximal cTnI release was 30±7 and 60±17, respectively, with additional cTnI release occurring after 150 min of reperfusion. Perfusion of hearts with the ?PKC-dF1Fo interaction inhibitor, prior to 20 min of ischemia and 60–150 min of reperfusion, reduced cTnI release by 80%. Additionally, we found that when soybean trypsin inhibitor (SBTI), was added to rat heart effluents, it could also be precipitated using (NH4)2SO4 and detected in western blots. This provided a convenient method for normalizing protein recoveries between groups. Our results support the further development of the ?PKC-dF1Fo inhibitor as a potential therapeutic for combating cardiac ischemic injury. In addition, we have developed an improved method for the detection of cTnI release from perfused rat hearts. PMID:23936451

  3. Barium uranyl diphosphonates

    SciTech Connect

    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

    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.

  4. Chondroitin sulfate

    MedlinePLUS

    ... with other products, including manganese ascorbate, glucosamine sulfate, glucosamine hydrochloride, or N-acetyl glucosamine. Research from a couple ... Early evidence suggests that chondroitin, with or without glucosamine hydrochloride, can reduce pain in people with Kashin-Beck ...

  5. Electron donors for biological sulfate reduction.

    PubMed

    Liamleam, Warounsak; Annachhatre, Ajit P

    2007-01-01

    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

  6. Barium uranyl diphosphonates

    NASA Astrophysics Data System (ADS)

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

    2012-08-01

    Three Ba2+/UO22+ methylenediphosphonates have been prepared from mild hydrothermal treatment of uranium trioxide, methylendiphosphonic acid (C1P2) with barium hydroxide octahydrate, barium iodate monohydrate, and small aliquots of HF at 200 °C. These compounds, Ba[UO2[CH2(PO3)2]·1.4H2O (Ba-1), Ba3[(UO2)4(CH2(PO3)2)2F6]·6H2O (Ba-2), and Ba2[(UO2)2(CH2(PO3)2)F4]·5.75H2O (Ba-3) all adopt layered structures based upon linear uranyl groups and disphosphonate molecules. Ba-2 and Ba-3 are similar in that they both have UO5F2 pentagonal bipyramids that are bridged and chelated by the diphosphonate moiety into a two-dimensional zigzag anionic sheet (Ba-2) and a one-dimensional ribbon anionic chain (Ba-3). Ba-1, has a single crystallographically unique uranium metal center where the C1P2 ligand solely bridges to form [UO2[CH2(PO3)2]2- sheets. The interlayer space of the structures is occupied by Ba2+, which, along with the fluoride ion, mediates the structure formed and maintains overall charge balance.

  7. Removal of Sulfate Ion From AN-107 by Evaporation

    SciTech Connect

    GJ Lumetta; GS Klinger; DE Kurath; RL Sell; LP Darnell; LR Greenwood; CZ Soderquist; MJ Steele; MW Urie; JJ Wagner

    2000-08-02

    Hanford low-activity waste solutions contain sulfate, which can cause accelerated corrosion of the vitrification melter and unacceptable operating conditions. A method is needed to selectively separate sulfate from the waste. An experiment was conducted to evaluate evaporation for removing sulfate ion from Tank AN-107 low-activity waste. Two evaporation steps were performed. In the first step, the volume was reduced by 55% while in the second step, the liquid volume was reduced another 22%. Analysis of the solids precipitated during these evaporations revealed that large amounts of sodium nitrate and nitrite co-precipitated with sodium sulfate. Many other waste components precipitated as well. It can be concluded that sulfate removal by precipitation is not selective, and thus, evaporation is not a viable option for removing sulfate from the AN-107 liquid.

  8. Discovery of the Barium Isotopes

    E-print Network

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

    2009-08-13

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

  9. Barium light source method and apparatus

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

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

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

    PubMed Central

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

    2013-01-01

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

  11. Barium and iron abundances in red giants

    SciTech Connect

    Fernandez-Villacanas, J.L.; Rego, M.; Cornide, M. (Madrid Universidad Complutense (Spain))

    1990-06-01

    An intermediate-dispersion abundance analysis has been carried out on a sample of 21 barium and 14 comparison stars. The excess of barium over iron has been used as the most representative indicator of peculiarity. These excesses are higher in the peculiar stars than in the nonpeculiar stars. Particularly interesting is the case of HD 67447, included in the comparison stars, with an excess Ba/Fe abundance = 1.61, probably a new barium star. A trend indicating a possible anticorrelation between barium overabundance and metallicity favors the suggestion that the barium strong group is older than the barium weak one. 36 refs.

  12. Optimized photorefractive barium titanate

    NASA Astrophysics Data System (ADS)

    Warde, Cardinal; Jenssen, Hans P.

    1992-03-01

    The goal of this research program was to investigate new and modified crystal-growth techniques that would lead to high-optical-quality BaTiO3 with increased photorefractive speed and sensitivity. The research program consisted of four parts: (1) feed material purification; (2) crystal growth by the top-seeded-solution technique as well as by a barium borate flux technique; (3) new furnace design studies; and (4) photorefractive characterization experiments. Iron and nickel-doped BaTiO3 crystals were grown under the program. BaTiO3 is a promising photorefractive material due to its large electrooptic coefficient and excellent self-pumped phase conjugation. Our furnaces were limited by certain design and operating characteristics, and crystals grown in these furnaces were easily contaminated by the furnace itself. Two new furnaces, cylindrical and octagonal furnaces, were developed with commercially available parts that are cleaner, more mechanically reproducible, more uniform in temperature and more responsive to control action through reduced thermal mass. The two furnaces are equipped with precise computer control of the pulling and rotation system. The cylindrical furnace was found to be susceptible to cracking due to expansion when heated and to shrinkage after heating. To prevent cracking, expansion joints were provided and the insulation set was made of flat plates set up in an octagonal pattern.

  13. Process for precipitating heavy metals from wastewater

    SciTech Connect

    Hallberg, R.O.

    1982-10-19

    A process is given for precipitating heavy metals from wastewater containing sulfate ions by treatment of the water with sulfate-reducing bacteria. Said bacteria will reduce the sulfate ions to hydrogen sulfide which in its turn will precipitate the metal ions in the form of metal sulfides. According to the invention the bacteria are cultured in one or more culturing vessels in the presence of a nutritive solution and a portion of the wastewater, and the resulting aqueous solution containing hydrogen sulfide produced by the bacteria is introduced into a precipitation vessel together with the remaining major portion of the wastewater.

  14. Preparation of a metalorganic deposition precursor for barium titanate

    SciTech Connect

    Apblett, A.W.; Georgieva, G.D.; Raygoza-Maceda, I. [Tulane Univ., New Orleans, LA (United States)

    1994-12-31

    A new, facile preparative route for BaTiO(Ox){sub 2} has been developed (Ox=oxalate). This involves passing a solution of K{sub 2}TiO(Ox){sub 2} through an ion-exchange resin to convert it to the proteo-derivative, H{sub 2}TiO(Ox){sub 2}. Treatment of the latter with BaCl{sub 2} results in precipitation of BaTiO(Ox){sub 2} with a ratio of barium:titanium of 1:1.009. Finally, reaction of BaTiO(Ox){sub 2} with refluxing methoxyacetic acid produces an alcohol and chlorocarbon soluble ceramic precursor that may be used to prepare thin films of barium titanate by metalorganic deposition.

  15. Interaction between Barium Oxide and Barium Containing Chloride Melt

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

  16. Barium Stars and Thermohaline Mixing

    SciTech Connect

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

    2008-01-24

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

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

    USGS Publications Warehouse

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

    1984-01-01

    High concentrations of dissolved barium have been found in ground water from bedrock wells on the Seneca Nation of Indians Reservation on Cattaraugus Creek in southwestern New York. Concentrations in 1982 were as high as 23.0 milligrams per liter , the highest found reported from any natural ground-water system in the world. The highest concentrations are in a bedrock aquifer and in small lenses of saturated gravel between bedrock and the overlying till. The bedrock aquifer is partly confined by silt, clay, and till. The high barium concentrations are attributed to dissolution of the mineral barite (BaSO4), which is present in the bedrock and possibly in overlying silt, clay, or till. The dissolution of barite seems to be controlled by action of sulfate-reducing bacteria, which alter the BaSO4 equilibrium by removing sulfate ions and permitting additional barite to dissolve. Ground water from the surficial, unconsolidated deposits and surface water in streams contain little or no barium. Because barium is chemically similar to calcium, it probably could be removed by cation exchange or treatments similar to those used for water softening. (USGS)

  18. Magnetic properties of barium ferrite synthesized using a microemulsion mediated process

    NASA Astrophysics Data System (ADS)

    Pillai, Vinod; Kumar, Promod; Shah, D. O.

    1992-10-01

    Ultrafine barium ferrite particles have been synthesized using a microemulsion mediated process. The aqueous cores (typically 10-25 nm in size) of water-in-oil microemulsions were used as constrained microreactors for the precipitation of precursor carbonates of Ba 2+ and Fe 3+. These precursors (5-15 nm in size) when heated at 950°C, transformed to the hexagonal ferrite BaFe 12O 19 as confirmed by X-ray diffraction. This barium ferrite powder had an intrinsic coercivity of 5089 Oe and a saturation magnetization of 60.1 emu/g.

  19. Chinese hamster ovary cell mutants defective in heparan sulfate biosynthesis

    SciTech Connect

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

    1987-05-01

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

  20. 40 CFR 721.10011 - Barium calcium manganese strontium oxide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 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...

  1. 40 CFR 721.10011 - Barium calcium manganese strontium oxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...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...

  2. 40 CFR 721.10011 - Barium calcium manganese strontium oxide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 2011-07-01 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...

  3. 40 CFR 721.10011 - Barium calcium manganese strontium oxide.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 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...

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

    NASA Technical Reports Server (NTRS)

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

    1975-01-01

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

  5. Barium in planktonic foraminifera

    SciTech Connect

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

    1991-11-01

    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.

  6. Sulfate Formation on Mars by Volcanic Aerosols: A New Look

    NASA Astrophysics Data System (ADS)

    Blaney, D. L.

    1996-03-01

    Sulfur was measured at both Viking Lander sites in abundances of 5-9 wt % SO3. Because the sulfur was more concentrated in clumps which disintegrated and the general oxidized nature of the Martian soil, these measurements led to the assumption that a sulfate duricrust existed. Two types of models for sulfate formation have been proposed. One is a formation by upwardly migrating ground water. The other is the formation of sulfates by the precipitation of volcanic aerosols. Most investigators have tended to favor the ground water origin of sulfates on Mars. However, evidence assemble since Viking may point to a volcanic aerosol origin.

  7. REMOVAL OF BARIUM AND RADIUM FROM GROUNDWATER

    EPA Science Inventory

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

  8. Quantum manipulation on the Barium quadrupolar transition

    E-print Network

    Blatt, Rainer

    and stabilization of a new fiber laser system to ma- nipulate the Barium quadrupolar transition, with the aim . . . . . . . . . . . . . . . 55 6 Spectroscopy and sideband cooling on a single 138 Ba+ 58 6.1 Quantum jumps using the fiber laser . . . . . . . . . . . . .Quantum manipulation on the Barium quadrupolar transition A diploma thesis in physics submitted

  9. pH control of the structure, composition, and catalytic activity of sulfated zirconia

    SciTech Connect

    Ivanov, Vladimir K. [Kurnakov Institute of General and Inorganic Chemistry of Russian Academy of Sciences, Leninsky ave., 31, Moscow 119991 (Russian Federation) [Kurnakov Institute of General and Inorganic Chemistry of Russian Academy of Sciences, Leninsky ave., 31, Moscow 119991 (Russian Federation); Materials Science Department, Moscow State University, Moscow 119991 (Russian Federation); Baranchikov, Alexander Ye., E-mail: a.baranchikov@yandex.ru [Kurnakov Institute of General and Inorganic Chemistry of Russian Academy of Sciences, Leninsky ave., 31, Moscow 119991 (Russian Federation); Department of Chemistry, Moscow State University, Moscow 119991 (Russian Federation); Kopitsa, Gennady P. [Petersburg Nuclear Physics Institute, Orlova Roscha, Gatchina 188300 (Russian Federation)] [Petersburg Nuclear Physics Institute, Orlova Roscha, Gatchina 188300 (Russian Federation); Lermontov, Sergey A.; Yurkova, Lyudmila L. [Institute of Physiologically Active Compounds of the Russian Academy of Sciences, Chernogolovka 142432 (Russian Federation)] [Institute of Physiologically Active Compounds of the Russian Academy of Sciences, Chernogolovka 142432 (Russian Federation); Gubanova, Nadezhda N. [Kurnakov Institute of General and Inorganic Chemistry of Russian Academy of Sciences, Leninsky ave., 31, Moscow 119991 (Russian Federation) [Kurnakov Institute of General and Inorganic Chemistry of Russian Academy of Sciences, Leninsky ave., 31, Moscow 119991 (Russian Federation); Petersburg Nuclear Physics Institute, Orlova Roscha, Gatchina 188300 (Russian Federation); Ivanova, Olga S.; Lermontov, Anatoly S. [Kurnakov Institute of General and Inorganic Chemistry of Russian Academy of Sciences, Leninsky ave., 31, Moscow 119991 (Russian Federation)] [Kurnakov Institute of General and Inorganic Chemistry of Russian Academy of Sciences, Leninsky ave., 31, Moscow 119991 (Russian Federation); Rumyantseva, Marina N. [Department of Chemistry, Moscow State University, Moscow 119991 (Russian Federation)] [Department of Chemistry, Moscow State University, Moscow 119991 (Russian Federation); Vasilyeva, Larisa P. [Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka 142432 (Russian Federation)] [Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka 142432 (Russian Federation); Sharp, Melissa; Pranzas, P. Klaus [GKSS Forschungszentrum, Geesthacht 21502 (Germany)] [GKSS Forschungszentrum, Geesthacht 21502 (Germany); Tretyakov, Yuri D. [Materials Science Department, Moscow State University, Moscow 119991 (Russian Federation)] [Materials Science Department, Moscow State University, Moscow 119991 (Russian Federation)

    2013-02-15

    We report a detailed study of structural and chemical transformations of amorphous hydrous zirconia into sulfated zirconia-based superacid catalysts. Precipitation pH is shown to be the key factor governing structure, composition and properties of amorphous sulfated zirconia gels and nanocrystalline sulfated zirconia. Increase in precipitation pH leads to substantial increase of surface fractal dimension (up to {approx}2.7) of amorphous sulfated zirconia gels, and consequently to increase in specific surface area (up to {approx}80 m{sup 2}/g) and simultaneously to decrease in sulfate content and total acidity of zirconia catalysts. Complete conversion of hexene-1 over as synthesized sulfated zirconia catalysts was observed even under ambient conditions. - Graphical abstract: Surface fractal dimension of amorphous sulfated zirconia and specific surface area and catalytic activity of crystalline sulfated zirconia as a function of precipitation pH. Highlights: Black-Right-Pointing-Pointer Structural transformation of amorphous hydrous zirconia into sulfated zirconia is studied. Black-Right-Pointing-Pointer Precipitation pH controls surface fractal dimension of amorphous zirconia gels. Black-Right-Pointing-Pointer Precipitation pH is the key factor governing properties of sulfated zirconia.

  10. Crystallization of Chicken Egg White Lysozyme from Sulfate Salts

    NASA Technical Reports Server (NTRS)

    Forsythe, Elizabeth; Pusey, Marc

    1998-01-01

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

  11. Lead removal and toxicity reduction from industrial wastewater through biological sulfate reduction process

    Microsoft Academic Search

    Paphungkorn Teekayuttasakul; Ajit P. Annachhatre

    2008-01-01

    The practicability of lead removal from sulfate-rich wastewater through biological sulfate reduction process with hydrogen as electron donor was investigated. Sulfide, which was converted from sulfate by a sulfate-reducing bacteria (SRB) in a gas-lift reactor, was used to remove lead as lead sulfide precipitate. Furthermore, the toxicity of wastewater in terms of whole effluent toxicity (WET) before and after treatment

  12. Sulfate Reduction at pH 4.0 for Treatment of Process and Wastewaters

    Microsoft Academic Search

    Martijn F. M. Bijmans; Erik de Vries; Chun-Hui Yang; Cees J. N. Buisman; Piet N. L. Lens; Mark Dopson

    2010-01-01

    Acidic industrial process and wastewaters often contain high sulfate and metal concentrations and their direct biological treatment is thus far not possible as biological processes at pH < 5 have been neglected. Sulfate-reducing bacteria convert sulfate to sulfide that can subsequently be used to recover metals as metal-sulfides precipitate. This study reports on high-rate sulfate reduction with a mixed microbial

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

    E-print Network

    Patton, Carl

    Electric field tunable 60 GHz ferromagnetic resonance response in barium ferrite-barium strontium barium strontium titanate films on Nb-doped strontium titanate substrates were capped with an unbonded comprised of a nominal 7 m thick yttrium iron garnet YIG film in contact with a 500 m thick barium strontium

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

    DOEpatents

    Zaromb, S.; Lawson, D.B.

    1994-02-15

    A process for recovering zinc-rich and iron-rich fractions from the baghouse dust that is generated in various metallurgical operations, especially in steel-making and other iron-making plants, comprises the steps of leaching the dust by hot concentrated sulfuric acid so as to generate dissolved zinc sulfate and a precipitate of iron sulfate, separating the precipitate from the acid by filtration and washing with a volatile liquid, such as methanol or acetone, and collecting the filtered acid and the washings into a filtrate fraction. The volatile liquid may be recovered by distillation, and the zinc may be removed from the filtrate by alternative methods, one of which involves addition of a sufficient amount of water to precipitate hydrated zinc sulfate at 10 C, separation of the precipitate from sulfuric acid by filtration, and evaporation of water to regenerate concentrated sulfuric acid. The recovery of iron may also be effected in alternative ways, one of which involves roasting the ferric sulfate to yield ferric oxide and sulfur trioxide, which can be reconverted to concentrated sulfuric acid by hydration. The overall process should not generate any significant waste stream. 1 figure.

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

    DOEpatents

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

    1994-01-01

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

  16. Preparation and characterization of uniform particles of flufenamic acid and its calcium and barium salts.

    PubMed

    Mohamed, Amr Ali; Matijevi?, Egon

    2012-09-01

    Uniform fully dispersed particles of flufenamic acid, a widely used anti-inflammatory drug, were prepared by two different methods. In the first one, the drug solution in organic solvents was added to a non-solvent (water or aqueous solutions of stabilizers); while in the second procedure the drug was precipitated by acidifying its basic aqueous solutions. In addition calcium and barium salts of uniform spherical particles were obtained by precipitation in aqueous basic solutions of the drug. These salts are supposed to improve the drug reactivity. The prepared dispersions of the drug and its salts were examined by scanning electron microscopy, X-ray diffractometry and electrophoresis. PMID:22703985

  17. Methods for sulfate removal in liquid-phase catalytic hydrothermal gasification of biomass

    DOEpatents

    Elliott, Douglas C; Oyler, James

    2013-12-17

    Processing of wet biomass feedstock by liquid-phase catalytic hydrothermal gasification must address catalyst fouling and poisoning. One solution can involve heating the wet biomass with a heating unit to a pre-treatment temperature sufficient for organic constituents in the feedstock to decompose, for precipitates of inorganic wastes to form, for preheating the wet feedstock in preparation for subsequent removal of soluble sulfate contaminants, or combinations thereof. Processing further includes reacting the soluble sulfate contaminants with cations present in the feedstock material to yield a sulfate-containing precipitate and separating the inorganic precipitates and/or the sulfate-containing precipitates out of the wet feedstock. Having removed much of the inorganic wastes and the sulfate contaminants that can cause poisoning and fouling, the wet biomass feedstock can be exposed to the heterogenous catalyst for gasification.

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

    SciTech Connect

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

    1985-01-01

    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.

  19. Barium ions for quantum computation

    NASA Astrophysics Data System (ADS)

    Dietrich, Matthew

    Barium ion is investigated as a hyperfine qubit. 137Ba + is trapped in a linear Paul trap and laser cooled. Isotope selective photoionization is employed to improve trapping from an isotopically inpure source. Optical pumping into the magnetically insensitive 2S 1/2(F=2) mF = 0 state is shown, and readout by electron shelving into the 2D5/2 is demonstrated both directly and by adiabatic passage. Rabi flops between the 2S1/2 F=1 and F=2 states is accomplished by exposure to 8.037 GHz microwave radiation. Several methods of locking the cooling lasers have been attempted and are discussed. Stabilization of the infrared laser used to drive the D 5/2 ? S1/2 transition is of particular interest, and several novel technologies are tested in this purpose.

  20. Barium Ions for Quantum Computation Matthew Dietrich

    E-print Network

    Blinov, Boris

    Barium Ions for Quantum Computation Matthew Dietrich A dissertation submitted in partial for Quantum Computation Matthew Dietrich Chair of the Supervisory Committee: Assistant Professor Boris Blinov trap and laser cooled. Isotope selective photoionization is employed to improve trapping from

  1. Dielectric and Piezoelectric Properties of Barium Titanate

    Microsoft Academic Search

    Shepard Roberts

    1947-01-01

    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

  2. Piezoresistive ceramic sensor based on PTCR barium titanate

    SciTech Connect

    Capurso, J.S.; Schulze, W.A.; Alles, A.B. [Alfred Univ., NY (United States)

    1994-12-31

    High purity, chemically prepared barium titanate was doped with 0.3 atom% La and 0.04 atom% Mn by precipitation. Using standard techniques, tape-cast sheets of the PTCR composition as well as the base insulating powder were made. A three-layer sensor was laminated with the upper and lower PTCR layers separated by an insulating BaTiO{sub 3} layer. After binder burnout, the device was sintered at 1350{degrees}C in flowing N{sub 2} followed by cooling in flowing O{sub 2} at 300{degrees}C/hour. The sensor was loaded using a standard four-point bend test configuration. The change in resistivity with increasing load was observed to the linear, with positive and negative piezoresistive coefficients for the PTCR layers under compression and tension, respectively. These trends are in general agreement with the Heywang-Jonker model of grain boundary potential barriers.

  3. Assessment of Barium Sulphate Formation and Inhibition at Surfaces with Synchrotron X-ray Diffraction (SXRD)

    SciTech Connect

    E Mavredaki; A Neville; K Sorbie

    2011-12-31

    The precipitation of barium sulphate from aqueous supersaturated solutions is a well-known problem in the oil industry often referred to as 'scaling'. The formation and growth of barite on surfaces during the oil extraction process can result in malfunctions within the oil facilities and serious damage to the equipment. The formation of barium sulphate at surfaces remains an important topic of research with the focus being on understanding the mechanisms of formation and means of control. In situ synchrotron X-ray diffraction (SXRD) was used to investigate the formation of barium sulphate on a stainless steel surface. The effect of Poly-phosphinocarboxylic acid (PPCA) and Diethylenetriamine-penta-methylenephosphonic acid (DETPMP) which are two commercial inhibitors for barium sulphate was examined. The in situ SXRD measurements allowed the identification of the crystal faces of the deposited barite in the absence and presence of the two inhibitors. The preferential effect of the inhibitors on some crystal planes is reported and the practical significance discussed.

  4. An ultrafine barium ferrite powder of high coercivity from water-in-oil microemulsion

    NASA Astrophysics Data System (ADS)

    Liu, Xiangyuan; Wang, John; Gan, Leong-Ming; Ng, Sen-Choon; Ding, Jun

    1998-05-01

    An ultrafine barium ferrite powder of high coercivity and high saturation magnetization has been successfully prepared from an inverse water-in-oil microemulsion consisting of cyclohexane, NP5/NP9, and an aqueous solution of mixed ferric nitrate and barium nitrate. An ammonium hydroxide solution was used as the precipitant to obtain the hydroxide precursor of particle size in the range of 10-30 nm from the microemulsion. The resulting precursor is characterized using techniques such as thermogravimetric analysis (TGA), differential thermal analysis (DTA) and a FT-IR analyzer. It was then calcined at various temperatures ranging from 600 to 950°C in order to develop the designed barium ferrite phase. Phase development in the precursor at each calcination temperature was monitored using X-ray diffractometer and a 57Fe-Mössbauer spectrometer analyzer. The particle size and size distribution of the calcined powders were determined using light scattering technique, scanning electron microscope and a transmission electron microscope. A high purity barium ferrite was obtained when the precursor was calcined at 950°C for 4 h. It exhibits an intrinsic coercivity ( iHc) of 5639 Oe and a saturation magnetization ( Ms) of 69.7 emu/g, when characterized using a vibrating sample magnetometer (VSM).

  5. Iron availability in mixed cultures of sulfate-reducing bacteria

    SciTech Connect

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

    1986-01-01

    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.

  6. Barium isotope fractionation during experimental formation of the double carbonate BaMn[CO3](2) at ambient temperature.

    PubMed

    Böttcher, Michael E; Geprägs, Patrizia; Neubert, Nadja; von Allmen, Katja; Pretet, Chloé; Samankassou, Elias; Nägler, Thomas F

    2012-09-01

    In this study, we present the first experimental results for stable barium (Ba) isotope ((137)Ba/(134)Ba) fractionation during low-temperature formation of the anhydrous double carbonate BaMn[CO(3)](2). This investigation is part of an ongoing work on Ba fractionation in the natural barium cycle. Precipitation at a temperature of 21±1°C leads to an enrichment of the lighter Ba isotope described by an enrichment factor of-0.11±0.06‰ in the double carbonate than in an aqueous barium-manganese(II) chloride/sodium bicarbonate solution, which is within the range of previous reports for synthetic pure BaCO (3) (witherite) formation. PMID:22462732

  7. Plagioclase dissolution during CO?-SO? cosequestration: effects of sulfate.

    PubMed

    Min, Yujia; Kubicki, James D; Jun, Young-Shin

    2015-02-01

    Geologic CO2 sequestration (GCS) is one of the most promising methods to mitigate the adverse impacts of global climate change. The performance of GCS can be affected by mineral dissolution and precipitation induced by injected CO2. Cosequestration with acidic gas such as SO2 can reduce the high cost of GCS, but it will increase the sulfate's concentration in GCS sites, where sulfate can potentially affect plagioclase dissolution/precipitation. This work investigated the effects of 0.05 M sulfate on plagioclase (anorthite) dissolution and subsequent mineral precipitation at 90 °C, 100 atm CO2, and 1 M NaCl, conditions relevant to GCS sites. The adsorption of sulfate on anorthite, a Ca-rich plagioclase, was examined using attenuated total reflectance Fourier-transform infrared spectroscopy and then simulated using density functional theory calculations. We found that the dissolution rate of anorthite was enhanced by a factor of 1.36 by the formation of inner-sphere monodentate complexes between sulfate and the aluminum sites on anorthite surfaces. However, this effect was almost completely suppressed in the presence of 0.01 M oxalate, an organic ligand that can exist in GCS sites. Interestingly, sulfate also inhibited the formation of secondary mineral precipitation through the formation of aluminum-sulfate complexes in the aqueous phase. This work, for the first time, reports the surface complexation between sulfate and plagioclase that can occur in GCS sites. The results provide new insights for obtaining scientific guidelines for the proper amount of SO2 coinjection and finally for evaluating the economic efficiency and environmental safety of GCS operations. PMID:25549263

  8. Heparan Sulfate Proteoglycans

    PubMed Central

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

    2011-01-01

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

  9. Precipitation Rate

    NSDL National Science Digital Library

    climvis.org

    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.

  10. Temperature-dependent coherent oscillation in photorefractive relaxor strontium barium

    E-print Network

    Osnabrück, Universität

    Temperature-dependent coherent oscillation in photorefractive relaxor strontium barium niobate M of the photorefractive light-induced scattering (beam fanning) in Sr0.61Ba0.39Nb2O6 (strontium barium niobate) doped

  11. Preparation and Properties of Barium Titanate Nanopowder\\/Epoxy Composites

    Microsoft Academic Search

    J. Chandradass; Dong-sik Bae

    2008-01-01

    This article is focused on the preparation of barium titanate nanopowder\\/epoxy composites and studying the effect of barium titanate nanopowder on improving mechanical and thermal characteristics of the epoxy polymer. Composites are prepared by dispersing barium titanate nanopowder in epoxy resin and, subsequently, cross-linking by using diamino diphenyl methane (DDM) curing agents. Synthesis of barium titanate nanopowder\\/epoxy composites is carried

  12. Wnts, Signaling and Sulfates

    NSDL National Science Digital Library

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

    2001-09-25

    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.

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

    SciTech Connect

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

    1984-05-01

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

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

    PubMed

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

    2013-01-15

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

  15. Removal of sulfate from high-strength wastewater by crystallisation.

    PubMed

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

    2009-02-01

    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

  16. Improved spectrophotometric analysis of barium styphnate

    SciTech Connect

    Brown, N E; Blasi, J A

    1983-01-01

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

  17. Precipitation Recycling

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

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

  18. Acid Precipitation

    NSDL National Science Digital Library

    Tyser, Jim

    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.

  19. Kinetics of photoplasma of dense barium vapour

    NASA Astrophysics Data System (ADS)

    Kosarev, N. I.

    2015-03-01

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

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

    PubMed

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

    2012-07-11

    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

  1. Uranium Immobilization by Sulfate-reducing Biofilms

    SciTech Connect

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

    2004-04-01

    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.

  2. Acid precipitation in Norway: effects on aquatic fauna

    Microsoft Academic Search

    G. R. Hendrey; R. F. Wright

    1976-01-01

    The effects of acid precipitation on the aquatic fauna of Norwegian lakes and streams are reviewed. Among subjects discussed are the effects on water chemistry, especially pH, sulfate, nitrate, and phosphate concentration. Acid precipitation has resulted in severe damage to fish populations of all kinds especially salmonids. Massive fish kills are observed particularly in the spring. The acidification of the

  3. Acidic precipitation: Considerations for an air quality standard

    Microsoft Academic Search

    Lance S. Evans; George R. Hendrey; Gary J. Stensland; Dale W. Johnson; A. J. Francis

    1981-01-01

    Acidic precipitation, wet or frozen precipitation with a H+ concentration greater than 2.5 µeq l-1, is a significant air pollution problem in the United States. The chief anions accounting for the H+ in rainfall are nitrate and sulfate. Agricultural systems may derive greater net nutritional benefits from increasing inputs of acidic rain than do forest systems when soils alone are

  4. Immunoaffinity centrifugal precipitation chromatography.

    PubMed

    Qi, Lin; Ito, Yoichiro

    2007-06-01

    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

  5. Effect of antiscalants on precipitation of an RO concentrate: metals precipitated and particle characteristics for several water compositions.

    PubMed

    Greenlee, Lauren F; Testa, Fabrice; Lawler, Desmond F; Freeman, Benny D; Moulin, Philippe

    2010-04-01

    Inland brackish water reverse osmosis (RO) is economically and technically limited by the large volume of salty waste (concentrate) produced. The use of a controlled precipitation step, followed by solid/liquid separation (filtration), has emerged as a promising side-stream treatment process to treat reverse osmosis concentrate and increase overall system recovery. The addition of antiscalants to the RO feed prevents precipitation within the membrane system but might have a deleterious effect on a concentrate treatment process that uses precipitation to remove problematic precipitates. The effects of antiscalant type and concentration on salt precipitation and precipitate particle morphology were evaluated for several water compositions. The primary precipitate for the synthetic brackish waters tested was calcium carbonate; the presence of magnesium, sulfate, minor ions, and antiscalant compounds affected the amount of calcium precipitated, as well as the phases of calcium carbonate formed during precipitation. Addition of antiscalant decreased calcium precipitation but increased incorporation of magnesium and sulfate into precipitating calcium carbonate. Antiscalants prevented the growth of nucleated precipitates, resulting in the formation of small (100-200 nm diameter) particles, as well as larger (6-10 microm) particles. Elemental analysis revealed changes in composition and calcium carbonate polymorph with antiscalant addition and antiscalant type. Results indicate that the presence of antiscalants does reduce the extent of calcium precipitation and can worsen subsequent filtration performance. PMID:20172582

  6. Hydrazine Sulfate (PDQ®)

    Cancer.gov

    Expert-reviewed information summary about the use of hydrazine sulfate as a treatment for people with cancer. Note: The information in this summary is no longer being updated and is provided for reference purposes only.

  7. Numerical simulation of cementitious materials degradation under external sulfate attack

    Microsoft Academic Search

    S. Sarkar; S. Mahadevan; J. C. L. Meeussen; H. van der Sloot; D. S. Kosson

    2010-01-01

    A numerical methodology is proposed in this paper to simulate the degradation of cementitious materials under external sulfate attack. The methodology includes diffusion of ions in and out of the structure, chemical reactions which lead to dissolution and precipitation of solids, and mechanical damage accumulation using a continuum damage mechanics approach. Diffusion of ions is assumed to occur under a

  8. Recognition and prevention of barium enema complications.

    PubMed

    Williams, S M; Harned, R K

    1991-01-01

    The barium enema is a safe and accurate diagnostic study of the colon but, in rare cases, complications may result. Many of these can be prevented by proper equipment and careful attention to technique. When a complication does occur, prompt recognition and management is vital in decreasing morbidity and mortality. Perforation of the bowel is the most frequent serious complication, occurring in approximately 0.02% to 0.04% of patients. Rarely the colon may burst due to excessive transmural pressure alone. However, a colon weakened by iatrogenic trauma or disease is more likely to perforate during an enema than is a normal healthy bowel. Injury to the rectal mucosa or anal canal due to the enema tip or retention balloon is probably the most common traumatic cause of barium enema perforation. Inflation of a retention balloon within a stricture, neoplasm, inflamed rectum, or colostomy stoma is particularly hazardous. Recent deep biopsy or polypectomy with electrocautery makes the bowel more vulnerable to rupture. The tensile strength of the bowel wall is impaired in elderly patients, patients receiving long-term steroid therapy, and in disease states including neoplasm, diverticulitis, inflammatory bowel disease, and ischemia. Intraperitoneal perforation leads to a severe, acute peritonitis with intravascular volume depletion. The ensuing shock may be rapidly fatal. Prompt fluid replacement and laparotomy are essential. If the patient survives the initial shock and sepsis, later complications caused by dense intraperitoneal adhesions may develop. Extraperitoneal perforation is usually less catastrophic but may result in pain, sepsis, cellulitis, abscess, rectal stricture, or fistula. Intramural extravasation often forms a persistent submucosal barium granuloma which may ulcerate or be mistaken for a neoplasm. The most dramatic complication of barium enema is venous intravasation of barium. Fortunately, this is quite rare as it may be immediately lethal. Most cases have been attributed to trauma from the enema tip or retention balloon, mucosal inflammation, or misplacement of the tip in the vagina. Bacteremia has been found in as many as 23% of patients following barium enema and, in rare cases, may cause symptomatic septicemia. Other less common complications include barium impaction, water intoxication, allergic reactions, and cardiac arrhythmias. Preparatory laxatives and cleansing enemas have been implicated in some instances of dehydration, rectal trauma, water intoxication, and perforation. Careful review of the indications for examination, previous radiographs, and clinical history will identify many of the patients at greater risk for complications so that appropriate precautions may be observed.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:1889235

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

    SciTech Connect

    Lovera, P.; Bescop, P. le; Adenot, F. [CEA Centre de`Etudes de Saclay, Gif/Yvette (France)] [CEA Centre de`Etudes de Saclay, Gif/Yvette (France); Li, G. [CEA Centre d`Etudes de Saclay, Gif/Yvette (France)] [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)] [Japan Nuclear Fuel Ltd., Tokyo (Japan); Owaki, E. [Taisei Corp., Yokohama (Japan). Technology Research Center] [Taisei Corp., Yokohama (Japan). Technology Research Center

    1997-10-01

    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.

  10. Sulfate Transport and Release in Technogenic Soil Substrates: Experiments and Numerical Modeling

    NASA Astrophysics Data System (ADS)

    Schonsky, H.; Peters, A.; Lang, F.; Mekiffer, B.; Wessolek, G.

    2012-04-01

    In Berlin and many other cities technogenic soil substrates from World War II and building and construction debris in general play an important role for soil formation and solute transport in the vadose zone. The largest debris landfill in Berlin is the Teufelsberg. Sulfate release from the landfill poses threats for groundwater quality. The scope of this study is to determine the processes controlling sulfate release from soils containing rubble. Column leaching experiments were conducted to analyze sulfate mobilization from Teufelsberg topsoil material. Flow interruptions of one and seven days were introduced. Sulfate release was modeled using a geochemical simulation tool (HP1). The model considered water flux, solute transport and precipitation/dissolution with first order kinetics. Sulfate release increased after flow interruptions, although bromide breakthrough indicated physical equilibrium of transport processes. The model was applicable for qualitative description of our experimental results. The estimated equilibrium concentrations of sulfate were one to two orders of magnitude smaller than expected according to the equilibrium constant of gypsum. It is assumed that the mobilization of sulfate from calcite/gypsum co-precipitates determines the sulfate concentrations in the soil solution of the studied soils. If Sulfate release and transport from soils containing debris is modeled with literature values, sulfate concentrations will be overestimated by one to two orders of magnitude.

  11. Processing and Characterization of Proton Conducting Yttrium Doped Barium Zirconate for Solid Oxide Fuel Cell Applications

    NASA Astrophysics Data System (ADS)

    Babilo, Peter

    To address the wide range of reported conductivities in literature and investigate the viability of yttrium-doped barium zirconate (BaZr 1-xYxO3-delta) as a membrane in electrochemical devices, the factors governing the protonic transport properties have been explored, with the aim of attaining reproducible proton conductivity in well-densified samples. It was found that a small initial particle size and high temperature sintering in the presence of excess barium were essential. By this procedure, BaZr0.8Y0.2O3 with 93-99% of theoretical density and high total (bulk plus grain boundary) conductivity could be reliably prepared. Samples sintered in the absence of excess barium displayed yttria precipitates and a bulk conductivity that was reduced by more than two orders of magnitude. Hydrogen transport across grain boundaries has been explored and the specific conductivity found to be two orders of magnitude lower than the bulk. Microstructural optimization of the total grain boundary conductivity included both decreasing total grain boundary density as well as improving intrinsic grain boundary properties. To investigate the influence of defect chemistry on stability, proton solubility, and proton mobility; samples with yttrium dopant concentration of 30 and 40 mol % were prepared in addition to the 20 Y mol %. Lattice parameters obtained suggests the solubility of yttrium in barium zirconate to be at least 40 mol %. Thermogravimetric analysis of the barium zirconate system showed excellent chemical stability under CO2 and protonic defects to be approaching theoretical hydrogen concentration for 20, 30, and 40 Y mol %. Significant hydroxyl-dopant associations were observed, especially at lower temperatures, which trap protons and impede transport. To simplify processing procedures, the influence of transitional metal oxides additives (especially zinc oxide) on the densification and electrical properties of doped barium zirconate have been examined. With the use of zinc oxide as a sintering aid, BaZr0.85Y0.15O3 was readily sintered to above 93% of theoretical density at 1300 °C. SEM investigations showed Zn accumulation in the intergranular regions. Electromotive force measurements of BaZr0.8Y0.2O3 showed the ionic transference number under fuel cell conditions to be at least 0.92 at 600 °C. Fuel cells based on BYZ20 were prepared and characterized.

  12. Densities of liquid metals: calcium, strontium, barium

    Microsoft Academic Search

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

    1977-01-01

    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

  13. PhotoElastic Effect in Barium Nitrate

    Microsoft Academic Search

    S. Bhagavantam; D. Suryanarayana

    1948-01-01

    DURING the course of our investigations on photo-elasticity, we have found that single crystals of barium nitrate behave in many respects in an exceptional manner. Differences between the stress-optical constants as determined by a Babinet compensator are (q11 - q12) = - 23.81 × 10-13, (q11 - q13) = - 18.06 × 10-13 and q44 = - 1.62 × 10-13

  14. Acidic precipitation

    SciTech Connect

    Martin, H.C.

    1987-01-01

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

  15. Elaboration and characterization of barium silicate thin films.

    PubMed

    Genevès, T; Domenichini, B; Imhoff, L; Potin, V; Heintz, O; Peterlé, P M; Bourgeois, S

    2008-12-01

    Room temperature depositions of barium on a thermal silicon oxide layer were performed in ultra high vacuum (UHV). In-situ X-ray photoelectron spectroscopy (XPS) analyses were carried out as well after exposure to air as after subsequent annealings. These analyses were ex-situ completed by secondary ion mass spectrometry (SIMS) profiles and transmission electron microscopy (TEM) cross-sectional images. The results showed that after air exposure, the barium went carbonated. Annealing at sufficient temperature permitted to decompose the carbonate to benefit of a barium silicate. The silicate layer was formed by interdiffusion of barium with the initial SiO2 layer. PMID:18603436

  16. The role of barium esophagography in an endoscopy world.

    PubMed

    Katzka, David A

    2014-10-01

    Barium esophagography, although an old test, remains important to the understanding of esophageal physiology and diagnosis of esophageal disorders. It provides additive and/or confirmatory information to endoscopy and is the more accurate means of yielding diagnosis. Barium esophagography allows correlation of symptoms with barium findings and with varied textures substances. It allows, particularly for oropharyngeal dysfunction, implementation therapeutic maneuvers and instructions while testing. The caveat to maintaining the benefits of barium esophagography is continuing to promote and support expertise from our radiologists in performing these studies, which has been challenged by our cost-efficient and high-tech medical society. PMID:25216903

  17. Sulfate could mediate the therapeutic effect of glucosamine sulfate

    Microsoft Academic Search

    L. John Hoffer; Ludmila N. Kaplan; Mazen J. Hamadeh; Ariadna C. Grigoriu; Murray Baron

    2001-01-01

    Glucosamine sulfate is a controversial osteoarthritis remedy that is presumed to stimulate articular cartilage glycosaminoglycan synthesis by increasing glucosamine concentrations in the joint space. However, this is not plausible because even large oral doses of the product have no effect on serum glucosamine concentrations. We propose instead that sulfate could mediate the clinical benefit attributed to this treatment. Sulfate is

  18. Polymorphic change from vaterite to aragonite under influence of sulfate: The "morning star" habit

    NASA Astrophysics Data System (ADS)

    Wagterveld, R. M.; Yu, M.; Miedema, H.; Witkamp, G. J.

    2014-02-01

    The presence of sulfate in reverse osmosis drinking water concentrate and its effect on calcium carbonate precipitation was studied, notably the overall kinetics of CaCO3 formation and the types of polymorphs formed. CaCO3 formation slows down with increasing sulfate concentration and the preferential polymorph shifts from vaterite to aragonite with increasing sulfate concentration. With this polymorphic change, a new combined habit is observed where aragonite spikes grow on top of vaterite ("morning star" habit). The presence of a moderate magnesium concentration results in the shift of vaterite to aragonite at relatively low sulfate concentrations; where sulfate and magnesium appear to have an additive effect. Without magnesium, spikes on top of vaterite were also observed, but only at relatively high sulfate concentration. Without the presence of magnesium, single crystals of aragonite were not found.

  19. Aluminum Sulfate 18 Hydrate

    ERIC Educational Resources Information Center

    Young, Jay A.

    2004-01-01

    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.

  20. The performance, kinetics and microbiology of sulfidogenic fluidized-bed treatment of acidic metal- and sulfate-containing wastewater

    Microsoft Academic Search

    A. H. Kaksonen; J. J. Plumb; W. J. Robertson; M. Riekkola-Vanhanen; P. D. Franzmann; J. A. Puhakka

    2006-01-01

    A sulfidogenic fluidized-bed reactor (FBR) process was developed for treating acidic metal- and sulfate-containing wastewater. The process operating parameters were determined and the bacterial diversity of the FBR was described. The process was based on sulfate reduction by sulfate-reducing bacteria (SRB), precipitation of metals as sulfides with the biogenic H2S and neutralization of the water with biologically produced bicarbonate alkalinity.

  1. Precipitation chemistry in central Amazonia

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

    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.

  2. Novel membrane potentiometric sulfate ion sensor based on zinc-phthalocyanine for the quick determination of trace amounts of sulfate.

    PubMed

    Ganjali, Mohammad Reza; Pourjavid, Mohammad Reza; Shamsipur, Mojtaba; Poursaeri, Taherh; Rezapour, Morteza; Javanbakht, Mehran; Sharghi, Hashem

    2003-07-01

    Poly(vinyl chloride) (PVC) based membranes of zinc-phthalocyanine (ZPC) with hexadecyltrimethylammonium bromide (HTAB) as a cation excluder, and dibutyl phthalate (DBP) and benzyl acetate (BA) as plasticizing solvent mediators were prepared and investigated as a SO4(2-) selective electrode. The best performance was observed with a membrane having a composition of ZPC-PVC-HTAB-BA in a ratio of 5%:32%:3%:60%, which works well over a wide concentration range (1.0 x 10(-2) - 1.0 x 10(-6) M) with a Nemstian slope of -29.2 mV per decade of activity, between the pH values of 2.0 to 7.0. This sensor shows a very fast response time of 10 s, and can be used over a period of 2 months with good reproducibility. The proposed sensor displays excellent selectivity for SO4(2-) over a large number of common inorganic anions. The sensor has been successfully applied for the direct and indirect determination of sulfate and zinc in zinc sulfate tablets, respectively. It was also used as an indicator electrode in the potentiometric titration of sulfate ions with barium ions. PMID:12880081

  3. APPLICATION OF NONINVASIVE PREGNANCY DIAGNOSIS IN BACTRIAN CAMELS (CAMELUS BACTRIANUS) USING CUBONI REACTION AND BARIUM CHLORIDE TEST.

    PubMed

    Fedorova, Tamara; Brandlová, Karolína; Lukešová, Daniela

    2015-06-01

    Pregnancy diagnoses in half-tamed animals are often very complicated. This study aimed to examine the alternative noninvasive and cheap methods of pregnancy diagnosis from urine in domestic Bactrian camels ( Camelus bactrianus ). Urine from 14 female camels kept in four European zoologic gardens was collected and tested by two chemical tests-Cuboni reaction and barium chloride test. The Cuboni reaction was significantly (P < 0.01) affected by the pregnancy status of female camels. The total accuracy of the Cuboni reaction was 70.5% but it increased significantly (P < 0.05) in the time leading up to parturition. The accuracy was 100% in the 3rd third of pregnancy. Urine of nonpregnant females did not react with a solution of barium chloride while, contrary to other studies, white precipitates formed mostly (80 to 100%) in urine of pregnant females. This study concluded that the Cuboni reaction is applicable for pregnancy diagnosis in camels. PMID:26056893

  4. The first barium tin(II) bromide fluoride

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

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

  5. Excessive barium and radium 226 in Illinois drinking water

    Microsoft Academic Search

    Calabrese

    1977-01-01

    The Illinois EPA has found 16 cities with drinking water containing barium concentrations exceeding the current state and federal drinking water standard of 1 mg\\/l. In addition, the presence of varying amounts of alpha activity reveal traces of radium-226 in many Illinois water wells. Increased levels of radium and barium are concurrent with a rise in cancer rates in the

  6. PHOTOSENSITIVE CENTERS AND CHARGE TRANSFER PROCESSES IN BARIUM CALCIUM TITANATE

    E-print Network

    Malovichko, Galina

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

  7. Integrated Salts Precipitation and Nano Filtration as Pretreatment of Multi Stage Flash Desalination System

    Microsoft Academic Search

    Aiman E. Al-Rawajfeh; Hassan E. S. Fath; A. A. Mabrouk

    2011-01-01

    In this paper, the effect of salts precipitators (SP) and Nano Filtration (NF) on the scale deposits of Multi Stage Flash (MSF) has been studied using Skillman index for estimating the likelihood of calcium sulfate scaling. The analysis was carried out to study the sulfate scale potential for seawater with 0 to 100% pre-treated make-up in MSF reference plant. The

  8. Integrated Salts Precipitation and NanoFiltration as Pretreatment of Multistage Flash Desalination System

    Microsoft Academic Search

    Aiman E. Al-Rawajfeh; Hassan E. S. Fath; A. A. Mabrouk

    2012-01-01

    In this paper, the effect of salts precipitators (SP) and nano-filtration (NF) on the scale deposits of multistage flash (MSF) is studied using the Skillman index for estimating the likelihood of calcium sulfate scaling. The analysis was carried out to study the sulfate scale potential for seawater with 0 to 100% pretreated make-up in an MSF reference plant. The results

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

    SciTech Connect

    Sugumaran, G.; Silbert, J.E.

    1988-04-05

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

  10. Barium Enhancement in NGC 6819 Blue Stragglers

    NASA Astrophysics Data System (ADS)

    Milliman, Katelyn; Mathieu, Robert D.; Schuler, Simon C.

    2015-01-01

    Possible formation pathways for blue straggler stars include mergers in hierarchical triple systems, stellar collisions during dynamical encounters, and mass transfer from a giant companion. Extensive work on the blue stragglers in the old open cluster NGC 188 (7 Gyr) has led to exciting discoveries including a binary secondary mass distribution peaked at 0.5 MSolar and the detection of three young white dwarf binary companions. These indicate that mass transfer from an asymptotic giant branch star is the dominant mechanism for blue straggler formation in open clusters. Such mass transfer events should pollute the surface abundance of the blue straggler with nucleosynthesis products from the evolved donor. The other formation pathways, mergers and collisions, are predicted to produce no such enhancements. In an effort to move beyond NGC 188 and into other open clusters we present the first results of a surface abundance study of the blue stragglers in the intermediate-aged open cluster NGC 6819 (2.5 Gyr) using the Hydra multi-object spectrograph on the WIYN 3.5 m telescope. This part of our study centers on the s-process element barium as a tracer of formation via mass transfer. We compare the blue straggler surface abundance of barium to that of a sample of main-sequence stars in NGC 6819 and find multiple blue stragglers with anomalous abundances. Surprising, most of the blue stragglers with barium anomalies show no radial-velocity evidence for a companion. We gratefully acknowledge funding from the National Science Foundation under grant AST- 0908082 and the Wisconsin Space Grant Consortium.

  11. Scattering lengths of calcium and barium isotopes

    E-print Network

    U. Dammalapati; L. Willmann; S. Knoop

    2011-10-25

    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 40Ca 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.

  12. Scattering lengths of calcium and barium isotopes

    E-print Network

    Dammalapati, U; Knoop, S

    2011-01-01

    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 40Ca 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.

  13. Short-cavity squeezing in barium

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

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

  14. Effect of hydrothermal synthesis environment on the particle morphology, chemistry and magnetic properties of barium hexaferrite

    Microsoft Academic Search

    A. Ataie; M. R. Piramoon; I. R. Harris; C. B. Ponton

    1995-01-01

    Barium nitrate and iron nitrate have been used as precursors in the hydrothermal synthesis of barium hydroxide, iron oxide and barium hexaferrite sols under specified standard synthesis conditions (temperature, time, stirring, alkali concentration, amount of water and heating rate) as a function of the base species used during synthesis. The hydrothermal synthesis of barium hydroxide and iron oxide has been

  15. Processing of yttrium-doped barium zirconate for high proton conductivity

    E-print Network

    Processing of yttrium-doped barium zirconate for high proton conductivity Peter Babilo Materials the transport properties of yttrium-doped barium zirconate (BYZ) have been explored, with the aim of attaining. INTRODUCTION Doped perovskites, such as barium cerate (BaCeO3), strontium cerate (SrCeO3), and barium zirconate

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

    E-print Network

    Michalski, Greg

    sulfur species and results in the formation of acid rain.3,4 The pioneering work of Holt and Kumar,5) and indirect (cloud formation) aerosol effect. It is also the main end product of the oxidation of reduced

  17. Antithrombin activity and disaccharide composition of dermatan sulfate from different bovine tissues.

    PubMed

    Osborne, Simone A; Daniel, Robyn A; Desilva, Kirthi; Seymour, Robert B

    2008-03-01

    Dermatan sulfate is a glycosaminoglycan that selectively inhibits the action of thrombin through interaction with heparin cofactor II. Unlike heparin it does not interact with other coagulation factors and is able to inhibit thrombin associated with clots. This property has made dermatan sulfate an attractive candidate as an antithrombotic drug. Previous studies have showed that dermatan sulfate derived from porcine/bovine intestinal mucosa/skin or marine invertebrates is capable of stimulating heparin cofactor II-mediated thrombin inhibition in vitro. This biological activity is reported for the first time in this study using dermatan sulfate derived from mammalian tissues other than intestinal mucosa or skin. Ten different bovine tissues including the aorta, diaphragm, eyes, large and small intestine, esophagus, skin, tendon, tongue, and tongue skin were used to prepare dermatan sulfate-enriched fractions by anion exchange chromatography and acetone precipitation. Heparin cofactor II/dermatan sulfate-mediated thrombin inhibition measured in vitro revealed activity comparable to or higher than the commercial standard with 2-fold differences observed between some tissues. Analysis of the extracted dermatan sulfate using fluorophore-assisted carbohydrate electrophoresis revealed significant differences in the relative percentage of all the mono-sulfated disaccharides, in particular the predominant mammalian disaccharide uronic acid-->N-acetyl-D-galactosamine-4-O-sulfate, confirming previous reports regarding variations in sulfation in dermatan sulfate from different tissues. Overall, these findings demonstrate that dermatan sulfate extracted from a range of bovine tissues exhibits in vitro antithrombin activity equivalent to or higher than that observed for porcine intestinal mucosa, identifying additional sources of dermatan sulfate as potential antithrombotic agents. PMID:18156656

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

    SciTech Connect

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

    1997-12-31

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

  19. Recovery of fission product rare earth sulfates from Purex 1WW

    Microsoft Academic Search

    E. J. Wheelwright; W. H. Swift

    1961-01-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

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

    Microsoft Academic Search

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

    2010-01-01

    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

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

    NASA Technical Reports Server (NTRS)

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

    1983-01-01

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

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

    SciTech Connect

    Frey, N.A. [Materials Physics Laboratory, Physics Department, University of South Florida, 4202 East Fowler Avenue, Tampa, FL 33620 (United States); Heindl, R. [Materials Physics Laboratory, Physics Department, University of South Florida, 4202 East Fowler Avenue, Tampa, FL 33620 (United States); Srinath, S. [Materials Physics Laboratory, Physics Department, University of South Florida, 4202 East Fowler Avenue, Tampa, FL 33620 (United States); Srikanth, H. [Materials Physics Laboratory, Physics Department, University of South Florida, 4202 East Fowler Avenue, Tampa, FL 33620 (United States)]. E-mail: sharihar@cas.usf.edu; Dudney, N.J. [Solid State Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2005-08-11

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

  5. A high-altitude barium radial injection experiment

    NASA Technical Reports Server (NTRS)

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

    1980-01-01

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

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

    SciTech Connect

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

    1996-11-01

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

  7. Designed microstructures in textured barium hexaferrite

    NASA Astrophysics Data System (ADS)

    Hovis, David Brian

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

  8. Homogeneous precipitation of alumina precursors via enzymatic decomposition of urea

    Microsoft Academic Search

    Hidero Unuma; Shinichi Kato; Toshitaka Ota; Minoru Takahashi

    1998-01-01

    A modified homogeneous precipitation technique involving enzymatic decomposition of urea was proposed and was applied to the synthesis of alumina precursors. Spherical aluminum hydroxide aggregates were prepared at 298 K from aqueous solutions containing aluminum sulfate, urea and urease. In contrast to the conventional technique involving thermally induced decomposition of urea, the resultant aggregates were amorphous with no trace of

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

    SciTech Connect

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

    2000-08-23

    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.

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

    PubMed Central

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

    2014-01-01

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

  11. Magnetic properties of substituted barium ferrite powders

    SciTech Connect

    Gruskova, A. [Slovak Univ. of Technology, Bratislava (Slovakia). Dept. of Electrotechnology] [Slovak Univ. of Technology, Bratislava (Slovakia). Dept. of Electrotechnology

    1994-03-01

    Hexagonal barium ferrites were prepared using the citrate method. Cobalt and titanium were added in the amounts x from 0.2 to 1.1 ion/f.u. related to the formula BaCo{sub x}Ti{sub x}Fe{sub 12{minus}2x}O{sub 19}. The heat treatment has been applied in three steps of 550 C/5 hrs, 850 C/2 hrs and 1,100 C/2 hrs. The following magnetic properties have been achieved: H{sub c} {approximately} 80 kA/m, J{sub s} {approximately} 120 {times} 10{sup {minus}6} Tkg{sup {minus}1} m{sup 3}, and J{sub r} {approximately} 60 {times} 10{sup {minus}6} Tkg{sup {minus}1} m{sup 3} in the composition for which x is equal to 0.5 ion/f.u. The magnetic parameters have been measured by the vibration magnetometer.

  12. Determination of trace elements in triglycine sulfate solutions

    NASA Technical Reports Server (NTRS)

    Tadros, Shawky H.

    1993-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1983-01-01

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

  14. Calculated emission rates for barium releases in space

    NASA Technical Reports Server (NTRS)

    Stenbaek-Nielsen, H. C.

    1989-01-01

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

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

    PubMed Central

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

    2014-01-01

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

  16. Prompt ionization in the CRIT II barium releases

    Microsoft Academic Search

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

    1992-01-01

    Observations of electron and ion distributions inside a fast neutral barium jet in the ionosphere show significant fluxes within 4 km of release, presumably related to beam plasma instability processes involved in the Critical Ionization Velocity (CIV) effect. Electron fluxes exceeding 5 x 10 exp 12\\/sq cm-str-sec-keV were responsible for ionizing both the streaming barium and ambient oxygen. Resulting ion

  17. Molecular Structure of Sulfate ion

    NSDL National Science Digital Library

    2002-09-11

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

  18. Carbonate Associated Sulfate in a Stromatolite from the Eocene Green River Formation

    NASA Astrophysics Data System (ADS)

    Frantz, C.; Dawson, K.; Gleeson, D.; Denson, J.; Corsetti, F.; Berelson, W.; Hanselmann, K.; Spear, J.; Dawson, S.; de la Torre, J.; Johnson, H.; Stevenson, B. S.; 2008, G.

    2008-12-01

    We measured the carbonate associated sulfate (CAS: sulfate trapped in the carbonate crystal lattice at the time of precipitation) in a ~51 myo stromatolite from the Tipton-Wilkins Peak contact in the Greater Green River Basin in southern Wyoming. The 8-cm-thick microdigitate stromatolite contained two alternating microstructures: a precipitated carbonate fan fabric and a micritic fabric (including trapped detrital grains). CAS values for the precipitated layers clustered narrowly between 392-431ppm; given the precipitated fabric, we suggest that CAS reflects lake chemistry at the time of formation. Adjacent micritic layers, on the other hand, had much greater variation (321-3479ppm) and substantially higher average values per layer (519- 1170ppm); we hypothesize that these values probably may not represent actual lake evaporative environments, the likely source of the micrite. We used average CAS values in the precipitated layers to estimate sulfate concentrations in the Greater Green River Basin at the time of carbonate formation using a CAS vs. sulfate concentration relationship established in a modern analog system at Walker Lake, Nevada. Our analysis suggests that lake sulfate was ~1.5mM, implying a moderate level of sulfate. Better constraints on the rate of carbonate formation and the depth-to-volume relationships of the lake basin are required before quantitative lake depth fluctuation calculations can be done. In lakes where this information is well-constrained, CAS could be used to determine lake volume fluctuations on relatively fine timescales. However, care is required to ensure that grains tested are representative of the in situ environment (e.g. not detrital or shell material).

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

    PubMed

    ?ukasik-G??bocka, Magdalena; Sommerfeld, Karina; Han?, Anetta; Grzegorowski, Adam; Bara?kiewicz, Danuta; Gaca, Micha?; Zieli?ska-Psuja, Barbara

    2014-01-01

    A serious case of barium intoxication from suicidal ingestion is reported. Oral barium chloride poisoning with hypokalemia, neuromuscular and cardiac toxicity, treated with intravenous potassium supplementation and hemodialysis, was confirmed by the determination of barium concentrations in gastric contents, blood, serum and urine using the inductively coupled plasma mass spectrometry method. Barium concentrations in the analyzed specimens were 20.45 µg/L in serum, 150 µg/L in blood, 10,500 µg/L in urine and 63,500 µg/L in gastric contents. Results were compared with barium levels obtained from a non-intoxicated person. PMID:24794066

  20. Intestinal and Renal Effects of Low-Volume Phosphate and Sulfate Cathartic Solutions Designed for Cleansing the Colon: Pathophysiological Studies in Five Normal Subjects

    Microsoft Academic Search

    Viralkumar Patel; Michael Nicar; Michael Emmett; John Asplin; John A Maguire; Carol A Santa Ana; John S Fordtran

    2009-01-01

    OBJECTIVES:Ingestion of a concentrated low-volume phosphate solution produces copious diarrhea, which cleanses the colon, but it occasionally causes renal failure due to calcium phosphate precipitation in renal tubules. We hypothesized that a concentrated low-volume sulfate solution would be an equally effective cathartic, and that urine produced after sulfate would have less tendency to precipitate calcium salts than urine produced after

  1. Sulfur isotope signatures in gypsiferous sediments of the Estancia and Tularosa Basins as indicators of sulfate sources, hydrological processes, and microbial activity

    Microsoft Academic Search

    Anna Szynkiewicz; Craig H. Moore; Mihaela Glamoclija; Lisa M. Pratt

    2009-01-01

    In order to reconstruct paleo-environmental conditions for the saline playa lakes of the Rio Grande Rift, we investigated sediment sulfate sources using sulfur isotope compositions of dissolved SO42- ions in modern surface water, groundwater, and SO42- precipitated in the form of gypsum sediments deposited during the Pleistocene and Holocene in the Tularosa and Estancia Basins. The major sulfate sources are

  2. Glycosaminoglycan sulfation in murine splenocytes

    SciTech Connect

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

    1986-05-01

    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.

  3. Electrooptic and piezoelectric measurements in photorefractive barium titanate and strontium barium niobate

    SciTech Connect

    Ducharme, S.; Feinberg, J.; Neurgaonkar, R.R.

    1987-12-01

    The authors measured the low-frequency (''unclamped'') electrooptic and piezoelectric coefficients in undoped BaTiO/sub 3/ and Sr/sub x/Ba/sub 1-x/Nb/sub 2/O/sub 6/ (chi - 0.61) crystals using interferometric techniques. The contribution of the piezoelectric effect to the Pockels measurement is discussed. For an applied ac electric field in the range 0.1-200 V/cm, the electrooptic and piezoelectric effects are linear in the magnitude of of the applied field and independent of its frequency in the range of 10 Hz-100 kHz. The unclamped electrooptic coefficients of poled BaTiO/sub 3/ single crystals are r/sub 13/ = 19.5 +- 1 pm/V and r/sub 33/ = 97 +- 7 pm/V, and for strontium barium niobate are r/sub 13/ = 47 +- 5 pm/V and r/sub 33/ = 235 +- 21 pm/V, all measured at a wavelength of 514.5 nm and at T = 23/sup 0/C. For the barium titanate samples the measured Pockels coefficient r/sub c/ identical to r/sub 33/ - (n/sub 1//n/sub 3/)/sup 3/r/sub 13/ = 79 +- 6 pm/V in good agreement with the value r/sub c/ = 76 +- 7 pm/V computed from the above values of r/sub 13/ and r/sub 33/, where n/sub 1/ and n/sub 3/ are the ordinary and extraordinary indexes of refraction, respectively. The measured piezoelectric coefficient is d/sub 23/ = +28.7 +- 2 pm/V for barium titanate, and is d/sub 23/ = +24.6 +- 2 pm/V for strontium barium niobate. They also measured the photoreflective coupling of two optical beams in the crystals, and they show that the dependence of the coupling strength on beam polarization is in fair agreement with the measured values of the Pockels coefficients.

  4. Inhibition of sulfate-reducing and methanogenic activities of anaerobic sewer biofilms by ferric iron dosing.

    PubMed

    Zhang, Lishan; Keller, Jürg; Yuan, Zhiguo

    2009-09-01

    Ferric iron is commonly used for sulfide precipitation in sewers, thus achieving corrosion and odour control. Its impact on the activities of sulfate-reducing bacteria and methanogens in anaerobic sewer biofilms is investigated in this study. Two lab-scale rising main sewer systems fed with real sewage were operated for 8 months. One received Fe(3+) dosage (experimental system) and the other was used as a control. In addition to precipitating sulfide from bulk water, Fe(3+) dosage was found to significantly inhibit sulfate reduction and methane production by sewer biofilms. The experimental reactor discharged an effluent containing a higher concentration of sulfate and a lower concentration of methane in comparison with the reference reactor. Batch experiments showed that the addition of ferric ions reduced the sulfate reduction and methane production rates of the sewer biofilms by 60% and 80%, respectively. The batch experiments further showed that Fe(3+) dosage changed the final products of sulfate reduction with sulfide accounting for only 54% of the sulfate reduced. The other products could not be confirmed, but were not dissolved inorganic sulfur species such as sulfite or thiosulfate. The results suggest the addition of Fe(3+) at upstream locations would minimize the ferric salts required for achieving the same level of sulfide removal. Fe(3+) dosing could also substantially reduce the formation of methane, a potent greenhouse gas, in sewers. PMID:19576610

  5. 21 CFR 184.1261 - Copper sulfate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...Drugs 3 2010-04-01 2009-04-01 true Copper sulfate. 184.1261 Section 184.1261 Food...Specific Substances Affirmed as GRAS § 184.1261 Copper sulfate. (a) Copper sulfate (cupric sulfate, CuSO4 ·5H2...

  6. Dynamical influences on the distribution and loading of SO2 and sulfate over North America, the

    E-print Network

    for secondary sulfate, intermittent production associated with aqueous-phase reaction in clouds, and intermittent removal, mainly by precipitation. We have used a chemical transport and transformation model, and interpret the temporal evolution in terms of the controlling meteorological phenomena as discerned from

  7. 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...

  8. High H? ionic conductivity in barium hydride.

    PubMed

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

    2015-01-01

    With hydrogen being seen as a key renewable energy vector, the search for materials exhibiting fast hydrogen transport becomes ever more important. Not only do hydrogen storage materials require high mobility of hydrogen in the solid state, but the efficiency of electrochemical devices is also largely determined by fast ionic transport. Although the heavy alkaline-earth hydrides are of limited interest for their hydrogen storage potential, owing to low gravimetric densities, their ionic nature may prove useful in new electrochemical applications, especially as an ionically conducting electrolyte material. Here we show that barium hydride shows fast pure ionic transport of hydride ions (H(-)) in the high-temperature, high-symmetry phase. Although some conductivity studies have been reported on related materials previously, the nature of the charge carriers has not been determined. BaH2 gives rise to hydride ion conductivity of 0.2 S cm(-1) at 630 °C. This is an order of magnitude larger than that of state-of-the-art proton-conducting perovskites or oxide ion conductors at this temperature. These results suggest that the alkaline-earth hydrides form an important new family of materials, with potential use in a number of applications, such as separation membranes, electrochemical reactors and so on. PMID:25485988

  9. Chemical compositions of four barium stars

    E-print Network

    Liang, Y C; Chen, Y Q; Qiu, H M; Zhang, B

    2003-01-01

    Chemical compositions of four barium stars HD 26886, HD 27271, HD 50082 and HD 98839 are studied based on high resolution, high signal-to-noise Echelle spectra. Results show that all of them are disk stars. Their \\alpha and iron peak elements are similar to the solar abundances. The neutron-capture process elements are overabundant relative to the Solar. The heavy-element abundances of the strong Ba star HD 50082 are higher than those of other three mild Ba stars. Its mass is 1.32Msun (+0.28,-0.22Msun), and is consistent with the average mass of strong Ba stars (1.5Msun). For mild Ba star HD 27271 and HD 26886, the derived masses are 1.90Msun (+0.25,-0.20Msun) and 2.78Msun (+0.75,-0.78M_sun), respectively, which are consistent with the average mass of mild Ba stars. We also calculate the theoretical abundances of Ba stars by combining the AGB stars nucleosynthesis and wind accretion formation scenario of Ba binary systems. The comparisons between the observed abundance patterns of the sample stars with the th...

  10. Enhancement of Beam Fanning in Barium Titanate

    NASA Astrophysics Data System (ADS)

    Smith, Neil; Yarrison-Rice, Jan

    2001-10-01

    We have made initial measurements of the temporal evolution of beam fanning in photorefractive crystals with and without the use of a diffuser at the sample's input plane. Beam fanning is initiated through two beam coupling between the incident radiation and the light which scatters from impurities at or near the input plane of the crystal. An index of refraction grating is formed between input beam and the scattered beams in the +c-axis direction due to the electro-optic effect. As the index grating grows in strength more light is diverted into the scattered beams' direction. The result is a beam fan that is collected via a series of lenses and is imaged unto a CCD camera that records the build up as a function of time. A diffusing plate placed at the entrance face of the barium titanate increases the scattering of the incident beam. This allows more energy to be diverted from the propagating beam into the scattered beams and thus into the beam fan. The diffuser has been characterized with AFM measurements and typical width and heights of surface features are recorded. An imaging software package provides a method of analyzing the total intensity of the beam fan as it develops and times to steady state are determined. We find that beam fanning efficiency is enhanced with the diffuser.

  11. Prospects for Barium Tagging in Gaseous Xenon

    SciTech Connect

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

    2012-05-03

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

  12. Pyroelectric properties of barium strontium titanate films: Effect of thermal M. W. Cole,2

    E-print Network

    Alpay, S. Pamir

    Pyroelectric properties of barium strontium titanate films: Effect of thermal stresses J. Zhang,1 M pyroelectric properties of 001 -textured polycrystalline barium strontium titanate BaxSr1-xTiO3, BST films

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

    E-print Network

    Alpay, S. Pamir

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

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

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

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

  15. Volumetric determination of uranium titanous sulfate as reductant before oxidimetric titration

    USGS Publications Warehouse

    Wahlberg, J.S.; Skinner, D.L.; Rader, L.F., Jr.

    1957-01-01

    Need for a more rapid volumetric method for the routine determination of uranium in uranium-rich materials has led to the development of a method that uses titanous sulfate as a reductant before oxidimetric titration. Separation of the hydrogen sulfide group is not necessary. Interfering elements precipitated by cupferron are removed by automatic filtrations made simultaneously rather than by the longer chloroform extraction method. Uranium is reduced from VI to IV by addition of an excess of titanous sulfate solution, cupric ion serving as an indicator by forming red metallic copper when reduction is complete. The copper is reoxidized by addition of mercuric perchlorate. The reduced uranium is then determined by addition of excess ferric sulfate and titration with ceric sulfate. The method has proved to be rapid, accurate, and economical.

  16. L = 1.24 Conjugate Magnetic Field Line Tracing Experiments With Barium Shaped Charges

    Microsoft Academic Search

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

    1974-01-01

    Barium ions are well suited for tracing out magnetic field lines, because they resonantly scatter sunlight in several visible wavelengths and because ions are constrained to spiral about magnetic field lines while traveling freely parallel to the field. By use of high explosive shaped charges with hollow conical liners of barium metal, detonated above 500-km altitude, jets of barium plasma

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

    Microsoft Academic Search

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

    2004-01-01

    The purpose of this study was to perform CT colonography (CTC) without cathartic colon cleansing. Four groups of 3 patients were prepared the day before CTC with a dedicated low residue diet, a hydration control allowing 2 liters of fluid intake and barium as tagging agent. Four different barium regimens were investigated. Groups 1 and 3 ingested barium over 1

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

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2012-04-01 false Tannic acid and barium enema preparations. 201...Specific Drug Products § 201.304 Tannic acid and barium enema preparations. (a) It has become a widespread practice for tannic acid to be added to barium enemas to...

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

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Tannic acid and barium enema preparations. 201...Specific Drug Products § 201.304 Tannic acid and barium enema preparations. (a) It has become a widespread practice for tannic acid to be added to barium enemas to...

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

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Tannic acid and barium enema preparations. 201...Specific Drug Products § 201.304 Tannic acid and barium enema preparations. (a) It has become a widespread practice for tannic acid to be added to barium enemas to...

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

    E-print Network

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

  2. Optimization of High Tunability Barium Strontium Titanate Thin Films Grown by RF Magnetron

    E-print Network

    York, Robert A.

    Optimization of High Tunability Barium Strontium Titanate Thin Films Grown by RF Magnetron Abstract-- Barium strontium titanate is a solid solution perovskite with a field-dependent permittivity.7 MV/cm. I. INTRODUCTION In recent years there has been much interest in thin-film barium strontium

  3. Spectroscopy of Eu3+ ions in congruent strontium barium niobate crystals

    E-print Network

    Osnabrück, Universität

    Spectroscopy of Eu3+ ions in congruent strontium barium niobate crystals Ä. Andresen, A.-N. Bahar properties of single crystals of strontium barium niobate, grown from the congruently melting composition, electro-optic, pho- torefractive, and dielectric properties, the solid solution strontium barium niobate

  4. Introduction Strontium Barium Niobate k-Space Spectroscopy Results Conclusions Unraveling Relaxor Phase Transitions by

    E-print Network

    Osnabrück, Universität

    Introduction Strontium Barium Niobate k-Space Spectroscopy Results Conclusions Unraveling Relaxor 2009 WILLIAMSBURG WORKSHOP ON FUNDAMENTAL PHYSICS OF FERROELECTRICS #12;Introduction Strontium Barium ferroelectrics Introduction Strontium Barium Niobate k-Space Spectroscopy Results Conclusions SBN ­ SrxBa1-xNb2O6

  5. High tunability barium strontium titanate thin films for rf circuit applications

    E-print Network

    York, Robert A.

    High tunability barium strontium titanate thin films for rf circuit applications N. K. Pervez,a) P) Large variations in the permittivity of rf magnetron sputtered thin-film barium strontium titanate have/cm. © 2004 American Institute of Physics. [DOI: 10.1063/1.1818724] Barium strontium titanate (BST) is a solid

  6. Dielectric tunability of graded barium strontium titanate multilayers: Effect of thermal strains

    E-print Network

    Alpay, S. Pamir

    Dielectric tunability of graded barium strontium titanate multilayers: Effect of thermal strains M TEC of a multilayered barium strontium titanate Ba1-ySryTiO3 BST ferroelectric heterostructure such as barium strontium titanate Ba1-ySryTiO3 BST have emerged as leading candidates for such applications due

  7. Noncollinear Optical Frequency Doubling in Strontium Barium Niobate Arthur R. Tunyagi, Michael Ulex, and Klaus Betzler*

    E-print Network

    Osnabrück, Universität

    Noncollinear Optical Frequency Doubling in Strontium Barium Niobate Arthur R. Tunyagi, Michael Ulex of a novel noncollinear optical second-harmonic generation mechanism is reported. In strontium barium niobate mechanism which we detected in crystals of strontium barium niobate (SBN)--cone-shaped second

  8. Optimization of the tunability of barium strontium titanate films via epitaxial stresses

    E-print Network

    Alpay, S. Pamir

    Optimization of the tunability of barium strontium titanate films via epitaxial stresses Z.-G. Ban The tunability of epitaxial barium strontium titanate films is analyzed theoretically using a phenomenological.1063/1.1524310 I. INTRODUCTION Thin films of barium strontium titanate (BaxSr1 xTiO3, BST have long been recognized

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

    E-print Network

    Aksay, Ilhan A.

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

  10. 21 CFR 201.304 - Tannic acid and barium enema preparations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Tannic acid and barium enema preparations. 201...Specific Drug Products § 201.304 Tannic acid and barium enema preparations. (a) It has become a widespread practice for tannic acid to be added to barium enemas to...

  11. 21 CFR 201.304 - Tannic acid and barium enema preparations.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Tannic acid and barium enema preparations. 201...Specific Drug Products § 201.304 Tannic acid and barium enema preparations. (a) It has become a widespread practice for tannic acid to be added to barium enemas to...

  12. Cation non-stoichiometry in yttrium-doped barium zirconate: phase behavior, microstructure, and proton conductivity

    E-print Network

    Cation non-stoichiometry in yttrium-doped barium zirconate: phase behavior, microstructure as the predominant secondary phase and the barium zirconate reverting to an undoped composition. From the relative conductivity. Barium zirconate, specifically yttrium-doped BaZrO3, has attracted particular attention amongst

  13. Enhanced Sintering of Yttrium-Doped Barium Zirconate by Addition of ZnO

    E-print Network

    Haile, Sossina M.

    Enhanced Sintering of Yttrium-Doped Barium Zirconate by Addition of ZnO Peter Babilo and Sossina M properties of doped barium zirconate have been examined. With the use of zinc ox- ide as a sintering aid, Ba of the material under flowing CO2 showed ZnO-modified barium zirconate to exhibit excellent chemical stability

  14. Defect Chemistry of Yttrium-Doped Barium Zirconate: A Thermodynamic Analysis of Water Uptake

    E-print Network

    Defect Chemistry of Yttrium-Doped Barium Zirconate: A Thermodynamic Analysis of Water Uptake-based SOFCs.3 Of known proton conducting oxides, yttrium-doped barium zirconate (BYZ) is particularly mobile species. Doping with trivalent yttrium onto the tetravalent zirconium in barium zirconate

  15. Protamine precipitation of two reovirus particle types from polluted waters.

    PubMed Central

    Adams, D J; Ridinger, D N; Spendlove, R S; Barnett, B B

    1982-01-01

    Two forms of virus particle are released from reovirus-infected cell cultures, infectious reovirus and potentially infectious reovirus (PIV). PIV particle forms have a complete outer coat and are not infectious until the outer coat is altered or removed. The PIV concentration in polluted waters, however, has not been determined. Protamine sulfate precipitation, using 0.25% fetal bovine serum and 0.005% protamine sulfate for the first precipitation of the sample and 0.0025% for the second, was employed to concentrate infectious reovirus and PIV from water and sewage. Infectious reovirus and PIV particles were concentrated over 500-fold from river water inoculated with virus, and virus recoveries of between 80 and 100% were achieved. Virus precipitates stored at -20 degrees C as a protamine-virus concentrate showed a 5% loss of PIV after 14 days. Virus preparations were assayed, before and after treatment, with 200 micrograms of chymotrypsin per ml, using a fluorescent-antibody procedure. Protamine sulfate precipitation and fluorescent-antibody detection are effective ways to recover and assay reoviruses present in raw sewage. PMID:7138002

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

    SciTech Connect

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

    2011-05-15

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

  17. Prompt ionization in the CRIT II barium releases

    NASA Astrophysics Data System (ADS)

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

    1992-05-01

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

  18. Growth of Sulfate-Reducing Bacteria in Sulfate Brines and the Astrobiological Implications for Mars

    NASA Astrophysics Data System (ADS)

    Marnocha, C. L.; Chevrier, V. F.; Ivey, D. M.

    2011-03-01

    We suggest sulfate-reducing bacteria as a model for life on Mars, as sulfate brines have been shown to be stable in martian conditions. We have performed experiments to determine the survivability of these bacteria in high sulfate concentrations.

  19. Chemical compositions of four barium stars

    E-print Network

    Y. C. Liang; G. Zhao; Y. Q. Chen; H. M. Qiu; B. Zhang

    2003-12-15

    Chemical compositions of four barium stars HD 26886, HD 27271, HD 50082 and HD 98839 are studied based on high resolution, high signal-to-noise Echelle spectra. Results show that all of them are disk stars. Their \\alpha and iron peak elements are similar to the solar abundances. The neutron-capture process elements are overabundant relative to the Solar. The heavy-element abundances of the strong Ba star HD 50082 are higher than those of other three mild Ba stars. Its mass is 1.32Msun (+0.28,-0.22Msun), and is consistent with the average mass of strong Ba stars (1.5Msun). For mild Ba star HD 27271 and HD 26886, the derived masses are 1.90Msun (+0.25,-0.20Msun) and 2.78Msun (+0.75,-0.78M_sun), respectively, which are consistent with the average mass of mild Ba stars. We also calculate the theoretical abundances of Ba stars by combining the AGB stars nucleosynthesis and wind accretion formation scenario of Ba binary systems. The comparisons between the observed abundance patterns of the sample stars with the theoretical results show that wind accretion scenario can explain the abundance patterns of HD 50082 and HD 27271 well, but fail to explain the abundances of HD 26886. It means that the mild Ba star HD 26886, with shorter orbital period (P11000 d), may be either a star with the heavy elements enriched by itself or a "true Ba" star.

  20. Timed barium esophagram in achalasia types.

    PubMed

    Zanoni, A; Rice, T W; Lopez, R; Birgisson, S; Shay, S S; Thota, P N; Baker, M E; Raymond, D P; Blackstone, E H

    2015-01-01

    Relationships of timed barium esophagram (TBE) findings to achalasia types defined by high-resolution manometry (HRM) have not been elucidated. Therefore, we correlated preoperative TBE and HRM measurements in achalasia types and related these to patient symptoms and prior treatments. From 2006 to 2013, 248 achalasia patients underwent TBE and HRM before Heller myotomy. TBE height and width were recorded at 1 and 5 minutes; HRM measured lower esophageal sphincter mean basal pressure, integrated relaxation pressure (IRP), and mean esophageal body contraction amplitude. Achalasia was classified into types I (25%), II (65%), and III (9.7%). TBE height at 5 minutes was higher for I (median 8 cm; interquartile range 6-12) and II (8 cm; 8-11) than for III (1 cm; 0-7). TBE width at 5 minutes was widest (3 cm; 2-4), narrower in II (2 cm; 2-3), and narrowest in I (1 cm; 0-2), P < 0.001. Volume remaining at 1 and 5 minutes was lower in III (1 m(2) ; 0-16) than I (42 m(2) ; 17-106) and II (39 m(2) ; 15-60), highlighting poorer emptying of I and II. Increasing TBE width correlated with deteriorating morphology and function from III to II to I. Symptoms poorly correlated with TBE and HRM. Prior treatment was associated with less regurgitation, faster emptying, and lower IRP. Although TBE and HRM are correlated in many respects, the wide range of their measurements observed in this study reveals a spectrum of morphology and dysfunction in achalasia that is best characterized by the combination of these studies. PMID:24649871

  1. Barium Levels in Soils and Centella asiatica.

    PubMed

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

    2013-08-01

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

  2. Barium Tagging from nEXO Using Resonance Ionization Spectroscopy

    NASA Astrophysics Data System (ADS)

    Twelker, K.; Kravitz, S.

    nEXO is a 5-ton liquid enriched-xenon time projection chamber (TPC) to search for neutrinoless double-beta decay, designed to have the sensitivity to completely probe the inverted mass hierarchy of Majorana neutrinos. The detector will accommodate-as a background reduction technique-a system to recover and identify the barium decay product. This upgrade will allow a background-free measurement of neutrinoless double-beta decay and increase the half-life sensitivity of the experiment by at least one order of magnitude. Ongoing research and development includes a system to test barium extraction from liquid xenon using surface adsorption and Resonance Ionization Spectroscopy (RIS).

  3. Tunable dielectric properties of lead barium zirconate niobate films

    NASA Astrophysics Data System (ADS)

    Kuo, Ya-Ling; Wu, Jenn-Ming

    2006-09-01

    The effect of substitution of niobium for zirconium on tunable behavior of lead barium zirconate (PBZ) films was investigated. Lead barium zirconate niobate films were grown on Pt /Ti/SiO2/Si substrates using chemical solution deposition method. The substitution of Nb for Zr enhances tunable properties of PBZ films. The dielectric tunabilities are excellent, all higher than 45% with a maximum=60%. The substitution of Nb for Zr raises values of figure of merit (FOM) of films. The maximum FOM takes place at 5mol% Nb with a value of 90, which is about three times that of the corresponding PBZ film.

  4. Stability of Magnesium Sulfate Minerals in Martian Environments

    NASA Technical Reports Server (NTRS)

    Marion, G. M.; Kargel, J. S.

    2005-01-01

    Viking Lander, Pathfinder, and Mars Exploration Rover missions to Mars have found abundant sulfur in surface soils and rocks, and the best indications are that magnesium sulfates are among the key hosts. At Meridiani Planum, MgSO4 salts constitute 15 to 40 wt.% of sedimentary rocks. Additional S is hosted by gypsum and jarosite. Reflectance and thermal emission spectroscopy is consistent with the presence of kieserite (MgSO4 H2O) and epsomite (MgSO4*7H2O). Theoretically, the dodecahydrate (MgSO4*12H2O) should also have precipitated. We first examine theoretically which MgSO4 minerals should have precipitated on Mars, and then how dehydration might have altered these minerals.

  5. Maximizing recovery of water-soluble proteins through acetone precipitation.

    PubMed

    Crowell, Andrew M J; Wall, Mark J; Doucette, Alan A

    2013-09-24

    Solvent precipitation is commonly used to purify protein samples, as seen with the removal of sodium dodecyl sulfate through acetone precipitation. However, in its current practice, protein loss is believed to be an inevitable consequence of acetone precipitation. We herein provide an in depth characterization of protein recovery through acetone precipitation. In 80% acetone, the precipitation efficiency for six of 10 protein standards was poor (ca. ?15%). Poor recovery was also observed for proteome extracts, including bacterial and mammalian cells. As shown in this work, increasing the ionic strength of the solution dramatically improves the precipitation efficiency of individual proteins, and proteome mixtures (ca. 80-100% yield). This is obtained by including 1-30 mM NaCl, together with acetone (50-80%) which maximizes protein precipitation efficiency. The amount of salt required to restore the recovery correlates with the amount of protein in the sample, as well as the intrinsic protein charge, and the dielectric strength of the solution. This synergistic approach to protein precipitation in acetone with salt is consistent with a model of ion pairing in organic solvent, and establishes an improved method to recover proteins and proteome mixtures in high yield. PMID:24016582

  6. Biosynthesis of 3-O-sulfated heparan sulfate: unique substrate specificity of heparan sulfate 3-O-sulfotransferase isoform 5

    Microsoft Academic Search

    Jinghua Chen; Michael B. Duncan; Kevin Carrick; R. Marshall Pope; Jian Liu

    2003-01-01

    Heparan sulfate 3-O-sulfotransferase transfers sulfate to the 3-OH position of a glucosamine to generate 3-O-sulfated heparan sulfate (HS), which is a rare component in HS from natural sources. We previously reported that 3-O- sulfotransferase isoform 5 (3-OST-5) generates both an antithrombin-binding site to exhibit anticoagulant activity and a binding site for herpes simplex virus 1 glycoprotein D to serve as

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

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

    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).

  8. Volumetric determination of uranium using titanous sulfate as reductant before oxidimetric titration

    USGS Publications Warehouse

    Wahlberg, James S.; Skinner, Dwight L.; Rader, Lewis F.

    1956-01-01

    A new method for determining uranium in samples containing 0.05 percent or more U3O8, using titanous sulfate as reducing agent, is much shorter, faster, and has fewer interferences than conventional methods using reductor columns. The sample is dissolved with sulfuric, nitric, perchloric, and hydrofluoric acids. Elements that would otherwise form insoluble fluorides are kept in solution by complexing the fluoride ion with boric acid. A precipitation is made with cupferron to remove interfering elements. The solution is filtered to remove the precipitated cupferrates instead of extracting them with chloroform as is usually done. Filtration is preferred to extraction because any niobium that may be in solution forms an insoluble cupferrate that may be removed by filtering but is very difficult to extract with chloroform. Excess cupferron is destroyed by oxidizing with nitric and perchloric acids, and evaporating to dense fumes of sulfuric acid. The uranium is reduced to U(IV) by the addition of titanous sulfate, with cupric sulfate used as an indicator of the completeness of the reduction. Metallic copper is formed when all the uranium is reduced. The reduced copper is then reoxidized by the addition of mercuric perchlorate, an excess of ferric sulfate added, and the solution titrated immediately with standard ceric sulfate with ferroin as an indicator. Precision of the method compared favorable with methods in common use, both for uranium ores and for most types of uranium-rich materials.

  9. HEALTH EFFECTS OF HUMAN EXPOSURE TO BARIUM IN DRINKING WATER

    EPA Science Inventory

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

  10. Barium strontium titanate powders prepared by spray pyrolysis

    Microsoft Academic Search

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

    2005-01-01

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

  11. Original article Response to barium selenate supplementation in sheep

    E-print Network

    Boyer, Edmond

    group did not receive any supplement of Se and/or vitamin E. The two groups were managed under the sameOriginal article Response to barium selenate supplementation in sheep kept at pasture supplements in the prevention of dis- orders related to Se deficiency in sheep maintained at pasture

  12. REMOVING BARIUM AND RADIUM THROUGH CALCIUM CATION EXCHANGE

    EPA Science Inventory

    The removal of barium (Ba) and radium (Ra), which are found in many groundwater sources, was achieved in laboratory studies with an ion exchange process. In the studies, a strong acid resin in the calcium form effectively removed Ba(+2) and Ra (+2) to meet standards. The resin wa...

  13. BARIUM AND RADIUM REMOVAL FROM GROUNDWATER BY ION EXCHANGE

    EPA Science Inventory

    The primary objective of this study was to determine the applicability of weak acid exchange resin in the hydrogen form for removal of hardness, barium and radium from groundwater. Weak acid resin in the hydrogen form eliminates the addition of sodium to drinking water. The capac...

  14. 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 ...

  15. Ultra-low temperature processing of barium tellurate dielectrics

    NASA Astrophysics Data System (ADS)

    Kwon, Do-Kyun

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

  16. Acidic precipitation: considerations for an air-quality standard

    Microsoft Academic Search

    L. S. Evans; G. R. Hendrey; G. J. Stensland; D. W. Johnson; A. J. Francis

    1980-01-01

    Acidic precipitation, wet or frozen deposition with a hydrogen ion concentration greatern than 2.5 ..mu..eq l⁻¹ is a significant air pollution problem in the United States. The chief anions accounting for the hydrogen ions in rainfall are nitrate and sulfate. Agricultural systems are more likely to derive net nutritional benefits from increasing inputs of acidic rain than are forest systems

  17. Rock Star Precipitation

    NSDL National Science Digital Library

    In this lesson, the student will play the role of a famous musician planning a world tour with performances in outdoor amphitheaters in Chile, Venezuela, Greenland, and Maine (USA). Based on Monthly Precipitation Data for 2006 from MyNASAData website, the student will evaluate changes in monthly precipitation levels, draw conclusions about how precipitation data will determine dates for a world tour and infer locations and months best for performing live outdoor concert.

  18. Effect of the sulfide concentration on zinc bio-precipitation in a single stage sulfidogenic bioreactor at pH 5.5

    Microsoft Academic Search

    Martijn F. M. Bijmans; Pieter-Jan van Helvoort; Cees J. N. Buisman; Piet N. L. Lens

    2009-01-01

    Dissolved zinc is present in natural waters and process streams generated by the mining and metallurgical industry. These streams usually have a low pH. By using sulfate reducing bacteria, sulfide can be produced that precipitates with zinc as zinc sulfide (sphalerite), which can be easily separated from the wastewater and even reused as zinc concentrate. In this study, a sulfate

  19. Sulfate reduction and methanogenesis in marine sediments

    NASA Technical Reports Server (NTRS)

    Oremland, R. S.; Taylor, B. F.

    1978-01-01

    Methanogenesis and sulfate-reduction were followed in laboratory incubations of sediments taken from tropical seagrass beds. Methanogenesis and sulfate-reduction occurred simultaneously in sediments incubated under N2, thereby indicating that the two processes are not mutually exclusive. Sediments incubated under an atmosphere of H2 developed negative pressures due to the oxidation of H2 by sulfate-respiring bacteria. H2 also stimulated methanogenesis, but methanogenic bacteria could not compete for H2 with the sulfate-respiring bacteria.

  20. 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,...

  1. Status of copper sulfate - 2007

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A brief overview of the Technical Sections completed and being worked on for the New Animal Drug Application (NADA) for copper sulfate will be presented. Various aspects of these technical sections will be open for discussion. The update will include information and dates for both the initial labe...

  2. Phosphate, Nitrate, and Sulfate Biosensors

    Microsoft Academic Search

    Aziz Amine; Giuseppe Palleschi

    2004-01-01

    Construction and assembly of phosphate, nitrate, and sulfate biosensors has been reviewed to give readers up?to?date information on the state of the art in this area which is becoming more and more important for the solution of practical problems faced in the monitoring of food safety and the environment. Special attention was paid concerning the papers published during the last

  3. Status of copper sulfate - 2008

    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,...

  4. Evaporation, Condensation, and Precipitation

    NSDL National Science Digital Library

    Miss Brown

    2009-10-21

    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 ...

  5. Sulfate reduction below the sulfate-methane transition in Black Sea sediments

    NASA Astrophysics Data System (ADS)

    Holmkvist, Lars; Kamyshny, Alexey, Jr.; Vogt, Christoph; Vamvakopoulos, Kyriakos; Ferdelman, Timothy G.; Jørgensen, Bo Barker

    2011-05-01

    A sudden increase in salinity about 7000 years ago caused a shift in the deposited sediments of the Black Sea from limnic to brackish-marine. Due to the development of an anoxic deep water basin and a relatively high sulfate concentration, organic matter is mineralized primarily through sulfate reduction in modern Black Sea sediments. Earlier studies showed that sulfate-reducing bacteria are abundant within the limnic sub-surface sediment in spite of extremely low concentrations of sulfate and organic carbon. A main objective of the present study was therefore to understand the depth distribution of sulfate reduction across the different sediment units, even deep below the sulfate-methane transition. Our study combined experimental measurements of sulfate reduction using 35S radiotracer with analyses of sulfur and iron geochemistry in pore water and sediment. Potential sulfate reduction rates were measured with 35S in sediment samples that were amended with sulfate and organic substrates and incubated in time-series up to 48 h. Sulfate reduction could thereby be detected and quantified at depths where concentrations of sulfate were otherwise too low to enable calculation of the rates. The results demonstrate that sulfate-reducing bacteria are active several meters below the sulfate-methane transition in Black Sea sediments. The cryptic sulfate reduction below the sulfate-methane transition may be driven by sulfate produced from re-oxidation of reduced sulfur species with oxidized iron minerals buried in the deep limnic sediment.

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

    SciTech Connect

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

    1992-04-01

    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.

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

    SciTech Connect

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

    1992-04-01

    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.

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

    SciTech Connect

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

    1991-04-01

    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.

  9. Sulfate-selective PVC membrane electrode based on a strontium Schiff's base complex.

    PubMed

    Ganjali, Mohammad Reza; Norouzi, Parviz; Gol-Mohammadi, Mahmood; Mizani, Farhang; Poursaberi, Tahereh; Salavati-Niasari, Masoud; Shamsipur, Mojtaba; Hosseini, Morteza; Javanbakht, Mehran

    2003-01-01

    A strontium Schiff's base complex (SS) can be used as a suitable ionophore to prepare a sulfate-selective PVC-based membrane electrode. The use of oleic acid (OA) and hexadecyltrimethylammonium bromide (HTAB), as additives, and nitrobenzen (NB), dibutyl phthalate (DBP) and benzyl acetate (BA) as solvent mediators, were investigated. The best performance was observed with a membrane composition PVC: NB: SS: HTAB of 30%: 62%: 5%: 3% ratio. The resulting sensor works well over a wide concentration range (1.0 x 10(-2)-1.0 x 10(-6) M) with a Nernstian slope of -29.2 mV per decade of sulfate activity over a pH range 4.0-7.0. The limit of detection of the electrode is 5 x 10(-7) M. The proposed sensor shows excellent discriminating ability toward SO4(2-) ions with regard to many anions. It has a fast response time of about 15 s. The membrane electrode was used to the determination of zinc in zinc sulfate tablets. The sensor was also used as an indicator electrode in the potentiometric titration of SO4(2-) against barium ion. PMID:12940601

  10. The anaerobic treatment of sulfate containing wastewater

    Microsoft Academic Search

    A. Visser

    1995-01-01

    In the anaerobic treatment of sulfate containing wastewater sulfate reducing bacteria (SRB) will compete with methanogenic- (MB) and acetogenic bacteria (AB) for the available substrates such as hydrogen, acetate, propionate and butyrate. The outcome of this competition will determine the endproduct of the anaerobic mineralisation proces: methane or sulfide.The occurrence of the sulfate reduction proces is often considered unwanted due

  11. Conversion of alkali metal sulfate to the carbonate

    DOEpatents

    Sheth, Atul C. (Woodridge, IL)

    1982-01-01

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

  12. Crystallization of Chicken Egg White Lysozyme from Assorted Sulfate Salts

    NASA Technical Reports Server (NTRS)

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

    1998-01-01

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

  13. In-situ transmission electron microscopy crystallization studies of sol-gel-derived barium titanate thin films

    SciTech Connect

    Gust, M.C.; Mecartney, M.L. [Univ. of California, Irvine, CA (United States). Dept. of Chemical and Biochemical Engineering; Evans, N.D. [Oak Ridge Inst. for Science and Education, TN (United States); Momoda, L.A. [Hughes Research Lab., Malibu, CA (United States)

    1997-11-01

    Barium titanate (BaTiO{sub 3}) thin films that were derived from methoxypropoxide precursors were deposited onto (100) Si, Pt/Ti/SiO{sub 2}/(100) Si, and molecular-beam-epitaxy-grown (MBE-grown) (100) BaTiO{sub 3} on (100) Si substrates by spin coating. The crystallization behavior of the amorphous-gel films was characterized using in-situ transmission electron microscopy heating experiments, glancing-angle X-ray diffraction, and differential thermal analysis/thermogravimetric analysis. Amorphous-gel films crystallized at a temperature of {approximately}600 C to an intermediate nanoscale (5--10 nm) barium titanium carbonate phase, presumably BaTiO{sub 2}CO{sub 3}, that subsequently transformed to nanocrystalline (20--50 nm) BaTiO{sub 3}. Random nucleation in the bulk of the gel film was observed on all substrates. In addition, oriented growth of BaTiO{sub 3} was concurrently observed on MBE-grown BaTiO{sub 3} on (100) Si. High-temperature decomposition of the intermediate carbonate phase contributed to nanometer-scale residual porosity in the films. High concentrations of water of hydrolysis inhibited the formation of the intermediate carbonate phase; however, these sols precipitated and were not suitable for spin coating.

  14. Reduction of Np(V) and precipitation of Np(IV) by an anaerobic microbial consortium.

    PubMed

    Rittmann, Bruce E; Banaszak, James E; Reed, Donald T

    2002-01-01

    A combination of experimental, analytical, and modeling investigations shows that an anaerobic, sulfate-reducing consortium reduced Np(V) to Np(IV), with subsequent precipitation of a Np(IV) solid. Precipitation of Np(IV) during growth on pyruvate occurred before sulfate reduction began. H2 stimulated precipitation of Np(IV) when added alone to growing cells, but it slowed precipitation when added along with pyruvate. Increasing concentrations of pyruvate also retarded precipitation. Accumulation of an intermediate pyruvate-fermentation product--probably succinate--played a key role in retarding Np(IV) precipitation by complexing the Np(IV). Hydrogen appears to have two roles in controlling Np precipitation: donating electrons for Np(V) reduction and modulating intermediate levels. That Np(V) is microbially reduced and subsequently precipitated under anaerobic conditions has likely beneficial implications for the containment of Np on lands contaminated by radionuclides, but complexation by fermentation intermediates can prevent immobilization by precipitation. PMID:12688585

  15. Comportement des materiaux cimentaires: Actions des sulfates et de la temperature

    NASA Astrophysics Data System (ADS)

    Barbarulo, Remi

    The research work presented in this Ph.D. thesis is related to the nuclear waste underground repository concept. Concrete could be used in such a repository, and would be subjected to variations of temperature in presence of sulfate, a situation that could induce expansion of concrete. The research was lead in three parts: an experimental study of the possibility of an internal sulfate attack on mortars; an experimental study and modeling of the chemical equilibriums of the CaO-SiO2-Al2O 3-SO-H2O system; and a modeling of the mechanisms of internal and external sulfate attacks, and the effect of temperature. The results show that mortars can develop expansions after a steam-cure during hydration, but also when a long steam-cure is applied to one-year-old mortars, which is a new point. Ettringite precipitation can be considered as responsible for these expansions. The experimental study of the CaO-SiO2-Al2O 3-SO3-H2O system clarified the role of Calcium Silicate Hydrates (C-S-H) on chemical equilibriums of cementitious materials. Sulfate sorption on C-S-H has been studied in detail. The quantity of sulfate bound to the C-S-H mainly depends on the sulfate concentration in solution, on the Ca/Si ratio of the C-S-H and is not significantly influenced by temperature. Aluminium inclusion in the C-S-H seems to be a significant phenomenon. Temperature increases the calcium sulfoaluminate solubilities and thus increases sulfates concentration in solution. A modeling of the chemical system is proposed. Simulations of external sulfate attack (15 mmol/L of Na2SO 4) predict ettringite precipitation at 20 and 85°C. Simulation of internal sulfate attack was performed at a local scale (a hydrated cement grain). An initial inhomogeneity can lead, after a thermal curing at 85°C, to ettringite precipitation in zones originally free from ettringite. This new-formed ettringite could be the origin of the expansions.

  16. Removal of sulfide, sulfate and sulfite ions by electro coagulation.

    PubMed

    Murugananthan, M; Raju, G Bhaskar; Prabhakar, S

    2004-06-18

    The removal of various species of sulfur from beamhouse of tannery wastewater and also from synthetic samples was studied by electro-flotation technique. Consumable anodes of iron and aluminum and insoluble anode of titanium were tested as anodes. It was found that iron and aluminum anodes were effective for the removal of suspended solids, sulfide, sulfite and sulfate. Progress of simultaneous coagulation of suspended solids during electro-flotation was measured using particle size analysis. Coagulation was found to be essential for effective flotation of suspended solids. Metal ions generated in situ by electrolytic oxidation of anode were found to react with dissolved sulfide ions. Metal sulfides thus formed as colloidal suspension were coagulated and floated simultaneously by hydrogen bubbles generated from cathode. Simultaneous occurrence of precipitation, coagulation and flotation was observed during electro-flotation. X-ray diffraction studies were conducted to identify the nature of sulfide phase formed during electrolytic precipitation. The effect of pH, current density and initial concentration of pollutants was studied and the results are discussed. The removal of sulfite and sulfate ions is explained by zeta-potential measurements. PMID:15177743

  17. Influence of oxygen precipitation on copper precipitation in Czochralski silicon

    NASA Astrophysics Data System (ADS)

    Xu, Jin; Wang, Nating; Yang, Deren

    2012-05-01

    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.

  18. Sulfated polysaccharides purified from two species of padina improve collagen and epidermis formation in the rat.

    PubMed

    Kordjazi, Moazameh; Shabanpour, Bahareh; Zabihi, Ebrahim; Faramarzi, Mohammad Ali; Feizi, Farideh; Ahmadi Gavlighi, Hassan; Feghhi, Mohammad Amin; Hosseini, Seyed Abbas

    2013-01-01

    Sulfated polysaccharides have shown promising effects on wound healing processes along with many other biological activities. The sulfated polysaccharides extracted from two algae species habitats in Persian Gulf were studied in vivo for their effects on collagen formation and epidermal regeneration. The polysaccharides were purified from aqueous extracts of P. tetrastromatica and P. boergesenii using CaCl2 and ethanol precipitation. The sulfate content of each polysaccharide was determined. Two identical wounds (either burn or excision) were made on the back of 4 groups of male Wistar rats (10 rats per group) under anesthesia. The algal polysaccharide ointments (2%) were applied twice daily on one side and the other wound was treated with Eucerin (as control). The rats were sacrificed on day 7 or 14, and then the wound samples were examined for epidermal thickness by light microscope. Furthermore, hydroxyproline content (as a marker of collagen formation) was spectro-photometrically measured. The polysaccharides purified from P. boergesenii had higher sulfate content (32.6±1%) compared to P. tetrastromatica (19±1%). Both algal polysaccharides showed some improvements in collagen formation (hydroxyproline content) and epidermal thickness in both wound models compared to the vehicle. The sulfated polysaccharides purified from P. tetrastromatica and P. boergesenii seaweeds are able to induce collagen formation and epidermal regeneration in the two wound models. The superior healing properties of P. boergesenii polysaccharides might be correlated to its higher sulfate content. Both algal polysaccharides are good candidates for wound healing clinical trials. PMID:24551807

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

    PubMed

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

    2014-06-16

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

  20. Effect of COD\\/Sulfate Ratios on Batch Anaerobic Digestion Using Sulfate-Reduction Bacteria

    Microsoft Academic Search

    Heng-heng Cao; Hong-guo Zhang; Ding-gui Luo; Yong-heng Chen

    2011-01-01

    A study on effects of the COD\\/sulfate ratio on characteristics of sulfate-reduction bacteria (SRB) in activated sludge of a UASB reactor was performed in batch anaerobic digestion experiment. Changes of pH in samples were 7.22~8.17 which was beneficial to the growth of SRB with high sulfate removal efficiency. Sulfate reduction efficiencies of COD\\/sulfate ratios from 0.43 to 3.03 were 18.7(R1),

  1. Infrared Study of Superconductivity: Grating Coupled Plasmons in Yttrium BARIUM(2) COPPER(3) OXYGEN(7) and Gap Features in BARIUM(1-X) Potassium(x) Bismuth OXYGEN(3)

    Microsoft Academic Search

    Franklin John Dunmore

    1995-01-01

    The electrodynamic properties of two different superconductors, Barium Potassium Bismuth Oxide (BKBO) and Yttrium Barium Copper Oxide (YBCO) have been studied using the technique of transmission Fourier transform spectroscopy with liquid helium temperature bolometric detection. Plasmon resonances have been observed in far infrared transmission measurements on superconducting YBCO films. An Aluminum\\/Nichrome grating is used to couple infrared radiation to collective

  2. Global Precipitation Measurement Poster

    NASA Technical Reports Server (NTRS)

    Azarbarzin, Art

    2010-01-01

    This poster presents an overview of the Global Precipitation Measurement (GPM) constellation of satellites which are designed to measure the Earth's precipitation. It includes the schedule of launches for the various satellites in the constellation, and the coverage of the constellation, It also reviews the mission capabilities, and the mission science objectives.

  3. Fabrication of alumina nanofibers by precipitation reaction combined with heterogeneous azeotropic distillation process

    Microsoft Academic Search

    Xun Liu; Zhiguo Wu; Tianyou Peng; Ping Cai; Hongjin Lv; Wenlong Lian

    2009-01-01

    ?-Alumina nanofibers have been prepared from a precipitation reaction between aluminum ammonium sulfate and Baker's salt solutions followed by a heterogeneous azeotropic distillation process with N-butanol and calcination at 1173K. Experimental results indicate that the terminal pH value of the reaction mixture should be kept at 7.00–8.00 in order to obtain ?-Al2O3 nanofibers. The resulting spherical aluminum hydrate precipitates are

  4. Arsenic stabilization of calcium arsenate waste by hydrothermal precipitation of arsenical natroalunite

    Microsoft Academic Search

    J. Viñals; A. Sunyer; P. Molera; M. Cruells; N. Llorca

    2010-01-01

    The stabilisation of calcium arsenate waste from a copper smelter by precipitation of arsenical natroalunite has been investigated. This procedure could solve the problem of arsenical gypsum production because it is transformed into arsenic-free anhydrite. Natroalunite precipitation was studied at 180-200°C from the slurry obtained after H2SO4-leaching and ozonation of the original waste - using sodium and aluminum sulfates as

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

    NASA Technical Reports Server (NTRS)

    Forman, R.

    1976-01-01

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

  6. Chemical quality of precipitation at Greenville, Maine

    USGS Publications Warehouse

    Smath, J.A.; Potter, T.L.

    1987-01-01

    Weekly composite precipitation samples were collected at a rural site located in Greenville, Maine for analysis of trace metals and organic compounds. Samples collected during February 1982, through May 1984, were analyzed for cadmium, chromium, copper, lead, mercury, nickel, and zinc and during February 1982, through March 1983, for chlorinated hydrocarbon pesticides, pthalate ester plasticizers, and polychlorinated biphenyls. Deposition rates were computed. Data reported by the NADP (National Atmospheric Deposition Program) was used to evaluate the general chemical quality of the precipitation. The precipitation had relatively high concentrations of hydrogen ions, sulfate, and nitrate, compared to other constituents. Of the trace metals included for analysis, only copper, lead, and zinc were consistently detected. Lead concentrations exceeded the U.S. EPA recommended limit for domestic water supply in three samples. High deposition rates for some of the metals were episodic. Alpha-hexachlorocyclohexane was the only organic compound that was consistently detected (maximum 120 nanograms/L). None of the other organic compounds were detected in any of the samples. (Author 's abstract)

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

    SciTech Connect

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

    1990-03-01

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

  8. Historical and Short-Term Controls on Sulfate Reduction and Alkalinity Generation in Three Aquatic Ecosystems of

    E-print Network

    Vallino, Joseph J.

    precipitation, pyrite, sediments #12;Introduction First described as acid rain in 1852 by Scottish chemist Angus.19 to 13.47 mEq m-2 y-1 in freshwater sediments. Keywords: Sulfate reduction, alkalinity, acid Smith, all forms of atmospheric acid deposition continue to be an environmental problem faced

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

    EPA Science Inventory

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

  10. Relationships between sulfate and nitrate ion concentrations and rainfall pH for use in modeling applications

    NASA Astrophysics Data System (ADS)

    McNaughton, Daniel J.

    Precipitation chemistry data for the north-east United States are analysed to test relationships between anthropogenic sulfate and nitrate ion contributions and rainfall pH. Results are presented and an application of a derived regression equation is made to estimate rainfall pH values from long-range transport model deposition predictions.

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

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1976-01-01

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

  13. Dielectric function for doped graphene layer with barium titanate

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  14. Interactions between chloride and sulfate or silica removals from wastewater using an advanced lime-aluminum softening process: equilibrium modeling.

    PubMed

    Abdel-Wahab, Ahmed; Batchelor, Bill

    2007-05-01

    Interactions among chloride, sulfate, and silica removals from recycled industrial wastewater using an ultra-high lime with aluminum process (UHLA) were studied. An equilibrium model that is able to accurately predict the chemical behavior and interactions between chloride and sulfate or silica with UHLA at various initial conditions and chemical reagents was developed. X-ray diffraction (XRD) analysis was conducted to identify the precipitated solids formed in the UHLA process. Model predictions indicated that simultaneous removal of sulfate and chloride can be best described by the formation of a solid solution containing calcium chloroaluminate, calcium sulfoaluminate (ettringite), calcium monosulfate, tricalcium hydroxyaluminate, and tetracalcium hydroxyaluminate. However, simultaneous removal of silica and chloride can be best described by precipitation of calcium silicate and calcium aluminosilicate in addition to a solid solution containing calcium chloroaluminate, tricalcium hydroxyaluminate, and tetracalcium hydroxyaluminate. The XRD results indicated the presence of the same solids assumed by the equilibrium model. PMID:17571843

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

    Microsoft Academic Search

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

    2007-01-01

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

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

    Microsoft Academic Search

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

    2007-01-01

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

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

    Microsoft Academic Search

    Chu-Tsun Wu; Fu-Hsing Lu

    2005-01-01

    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

  18. Precipitation of mixtures of anionic and cationic surfactants; 3: Effect of added nonionic surfactant

    SciTech Connect

    Shiau, B.J.; Harwell, J.H.; Scamehorn, J.F. (Univ. of Oklahoma, Norman, OK (United States). Inst. for Applied Surfactant Research)

    1994-10-15

    The precipitation of an anionic surfactant by a cationic surfactant in the presence of a nonionic surfactant is examined. The precipitation domains for sodium dodecyl sulfate/dodecyl-pyridinium chloride were measured over a wide range of surfactant concentrations as a function of nonylphenol polyethoxylate concentration. Increasing the nonylphenol polyethoxylate concentration decreases the tendency for precipitation to occur. A model for predicting precipitation domains in ternary surfactant mixtures has been developed and verified experimentally. The model allows the nonionic surfactant to affect the precipitation behavior only by lowering the critical micelle concentration of the mixture. Small deviations between theory and experiments along part of the anionic-rich micelle boundary result from adsorption of SDS on the precipitate which gives the microcrystals a negative charge and prevents their growth to a visible size.

  19. The positive temperature coefficient of resistivity in barium titanate

    Microsoft Academic Search

    B. Huybrechts; K. Ishizaki; M. Takata

    1995-01-01

    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

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

    Microsoft Academic Search

    Jay L. Benson; Walter H. Johnson

    1966-01-01

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

  1. Elastic and Piezoelectric Coefficients of Single-Crystal Barium Titanate

    Microsoft Academic Search

    Don Berlincourt; Hans Jaffe

    1958-01-01

    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

  2. Luminescence of re 2+ (re = Sm, Yb) in barium octoborate

    Microsoft Academic Search

    Qinghua Zeng; Zhiwu Pei; Shubing Wang; Qiang Su; Shaozhe Lu

    1999-01-01

    The reduction process from trivalent to divalent state for Sm3+ and Yb3+ ions in barium borates (BaB8O13) prepared in air was observed. The luminescence properties of these divalent rare-earth ions were studied. Yb2+ shows an f-d broad emission band, due to the 4f14 ? 4f135d transition, while the Sm2+ ion shows an f ? f transition. From the spectra of

  3. Anomalous permittivity in fine-grain barium titanate

    Microsoft Academic Search

    Steven Paul Ostrander

    1997-01-01

    Fine-grain barium titanate capacitors exhibit anomalously large permittivity. It is often observed that these materials will double or quadruple the room temperature permittivity of a coarse-grain counterpart. However, aside from a general consensus on this permittivity enhancement, the properties of the fine-grain material are poorly understood. This thesis examines the effect of grain size on dielectric properties of a self-consistent

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

    SciTech Connect

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

    2001-01-14

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

  5. Cementation of ILW ion exchange resins: Impact of sulfate ions released by radiolysis on hydrated matrix

    NASA Astrophysics Data System (ADS)

    Frizon, F.; Cau-dit-Coumes, C.

    2006-12-01

    Some of the ion exchange resins used during treatment of spent nuclear fuels are intermediate level radioactive wastes which may be damaged by radiolysis process, releasing sulfate ions directly into the cement-based encapsulating material. This work consists in an experimental study of the resulting sulfate attack on the properties of the hydrated matrix: dimensional stability, mineralogy and microstructure of the samples, as well as variations in the chemical composition of the curing solution, were studied during six months. Three sites of delayed ettringite formation were detected: into the cement matrix near the surface exposed to solution, localized in the interfacial transition zone between cement matrix and resins, or progressively replacing the portlandite that initially fulfilled the cracks of anionic resins. During the experiment period, the ettringite precipitation and the expansion detected were moderate, and did not lead to cracking. The material involved was considered as having a good resistance to sulfate attack.

  6. Composite nanoplatelets combining soft-magnetic iron oxide with hard-magnetic barium hexaferrite

    NASA Astrophysics Data System (ADS)

    Primc, D.; Makovec, D.

    2015-01-01

    By coupling two different magnetic materials inside a single composite nanoparticle, the shape of the magnetic hysteresis can be engineered to meet the requirements of specific applications. Sandwich-like composite nanoparticles composed of a hard-magnetic Ba-hexaferrite (BaFe12O19) platelet core in between two soft-magnetic spinel iron oxide maghemite (?-Fe2O3) layers were synthesized using a new, simple and inexpensive method based on the co-precipitation of Fe3+/Fe2+ ions in an aqueous suspension of hexaferrite core nanoparticles. The required close control of the supersaturation of the precipitating species was enabled by the controlled release of the Fe3+ ions from the nitrate complex with urea ([Fe((H2N)2C&z.dbd;O)6](NO3)3) and by using Mg(OH)2 as a solid precipitating agent. The platelet Ba-hexaferrite nanoparticles of different sizes were used as the cores. The controlled coating resulted in an exclusively heterogeneous nucleation and the topotactic growth of the spinel layers on both basal surfaces of the larger hexaferrite nanoplatelets. The direct magnetic coupling between the core and the shell resulted in a strong increase of the energy product |BH|max. Ultrafine core nanoparticles reacted with the precipitating species and homogeneous product nanoparticles were formed, which differ in terms of the structure and composition compared to any other compound in the BaO-Fe2O3 system.By coupling two different magnetic materials inside a single composite nanoparticle, the shape of the magnetic hysteresis can be engineered to meet the requirements of specific applications. Sandwich-like composite nanoparticles composed of a hard-magnetic Ba-hexaferrite (BaFe12O19) platelet core in between two soft-magnetic spinel iron oxide maghemite (?-Fe2O3) layers were synthesized using a new, simple and inexpensive method based on the co-precipitation of Fe3+/Fe2+ ions in an aqueous suspension of hexaferrite core nanoparticles. The required close control of the supersaturation of the precipitating species was enabled by the controlled release of the Fe3+ ions from the nitrate complex with urea ([Fe((H2N)2C&z.dbd;O)6](NO3)3) and by using Mg(OH)2 as a solid precipitating agent. The platelet Ba-hexaferrite nanoparticles of different sizes were used as the cores. The controlled coating resulted in an exclusively heterogeneous nucleation and the topotactic growth of the spinel layers on both basal surfaces of the larger hexaferrite nanoplatelets. The direct magnetic coupling between the core and the shell resulted in a strong increase of the energy product |BH|max. Ultrafine core nanoparticles reacted with the precipitating species and homogeneous product nanoparticles were formed, which differ in terms of the structure and composition compared to any other compound in the BaO-Fe2O3 system. Electronic supplementary information (ESI) available: Synthesis (ESI #1) and properties (ESI #2) of the barium hexaferrite core nanoparticles, TEM of the nanoparticles synthesized under an excessive supersaturation (ESI #3), and magnetic properties of physical mixtures of the hard-magnetic hexaferrite and the soft-magnetic spinel ferrite (ESI #4). See DOI: 10.1039/c4nr05854b

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

    PubMed

    Ahlgren, Joakim; Djodjic, Faruk; Wallin, Mats

    2012-01-01

    In many catchments, anthropogenic input of contaminants, and in particular phosphorus (P), into surface water is a mixture of agricultural and sewage runoff. Knowledge about the relative contribution from each of these sources is vital for mitigation of major environmental problems such as eutrophication. In this study, we investigated whether the distribution of trace elements in surface waters can be used to trace the contamination source. Water from three groups of streams was investigated: streams influenced only by agricultural runoff, streams influenced mainly by sewage runoff, and reference streams. Samples were collected at different flow regimes and times of year and analyzed for 62 elements using ICP-MS. Our results show that there are significant differences between the anthropogenic sources affecting the streams in terms of total element composition and individual elements, indicating that the method has the potential to trace anthropogenic impact on surface waters. The elements that show significant differences between sources are strontium (p < 0.001), calcium (p < 0.004), potassium (p < 0.001), magnesium (p < 0.001), boron (p < 0.001), rhodium (p = 0.001), and barium (p < 0.001). According to this study, barium shows the greatest potential as a tracer for an individual source of anthropogenic input to surface waters. We observed a strong relationship between barium and total P in the investigated samples (R(2) = 0.78), which could potentially be used to apportion anthropogenic sources of P and thereby facilitate targeting of mitigation practices. PMID:22218189

  8. Toward remote ion-ion entanglement with barium

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  9. Structural properties of barium strontium titanate films grown under different technological conditions

    NASA Astrophysics Data System (ADS)

    Tumarkin, A. V.; Al'myashev, V. I.; Razumov, S. V.; Gaidukov, M. M.; Gagarin, A. G.; Altynnikov, A. G.; Kozyrev, A. B.

    2015-03-01

    The structural properties of ferroelectric barium strontium titanate films with different compositions prepared under different deposition conditions have been investigated. It has been shown that the deposition temperature directly affects the phase and component compositions of the films, crystal lattice parameters, and crystallite sizes. At a deposition temperature of approximately 600°C, impurity phases of strontium polytitanates are formed in addition to the barium strontium titanate phase. An increase in the deposition temperature to 880°C leads to a barium deficiency as compared to the sputtering target. The deposition temperature providing a stoichiometric transfer of the component composition of the target into the barium strontium titanate film has been estimated.

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

    SciTech Connect

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

    1988-01-01

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

  11. Linking Microbial Ecology to Geochemistry in Sulfate Reducing Systems

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  12. Modeling the crystal distribution of lead-sulfate in lead-acid batteries with 3D spatial resolution

    NASA Astrophysics Data System (ADS)

    Huck, Moritz; Badeda, Julia; Sauer, Dirk Uwe

    2015-04-01

    For the reliability of lead-acid batteries it is important to have an accurate prediction of its response to load profiles. A model for the lead-sulfate growth is presented, which is embedded in a physical-chemical model with 3D spatial resolution is presented which is used for analyzing the different mechanism influencing the cell response. One import factor is the chemical dissolution and precipitation of lead-sulfate, since its dissolution speed limits the charging reaction and the accumulation of indissolvable of lead-sulfate leads to capacity degradation. The cell performance/behavior is not only determined by the amount of the sulfate but also by the radii and distribution of the crystals. The presented model can be used to for an improved understanding of the interaction of the different mechanisms.

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

    Microsoft Academic Search

    Jörg Lewandowski; Inke Schauser; Michael Hupfer

    2003-01-01

    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).

  14. 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...

  15. FORMATION PROCESSES AND CONSEQUENCES OF REACTIVE AND NON-REACTIVE MINERAL PRECIPITATES IN PERMEABLE REACTIVE BARRIERS

    EPA Science Inventory

    Mineral precipitates in zero-valent iron PRBs can be classified by formation processes into three groups: 1) those that result from changes in chemical conditions (i.e., change in pH, e.g., calcite); 2) those that are a consequence of microbial activity (i.e., sulfate reduction, ...

  16. THE RECOVERY OF FISSION PRODUCT RARE EARTH SULFATES FROM PUREX 1WW

    Microsoft Academic Search

    E. J. Wheelwright; W. H. Swift

    1961-01-01

    Cerium- and 144 promethium-147, accompanied by rare earths resulting ;\\u000a from fission or decay can be removed from Purex 1WW in>90% yield as an ;\\u000a insoluble, crystalline sodium-rare earth double sulfate. Precipitation is ;\\u000a initiated by a one-to-three hour equilibration at 90 deg C and centrifugation at ;\\u000a 90 deg C to take advantage of the lower solubility of the

  17. Manganese and Sulfate Removal from a Synthetic Mine Drainage Through Pilot Scale Bioreactor Batch Experiments

    Microsoft Academic Search

    A. D. KarathanasisJ; J. D. Edwards; C. D. Barton

    2010-01-01

    Mine drainage is a significant problem in the Appalachian Plateau due to elevated metal and solute concentrations. Most metals\\u000a may be removed by oxidation\\/precipitation or natural buffering, but Mn is more difficult to remove due to its higher solubility.\\u000a Some mine drainages in southeastern Kentucky have average sulfate and Mn concentrations exceeding 1,300 and 30 mg L?1, respectively. Manganese does not readily

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

    Microsoft Academic Search

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

    1999-01-01

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

  19. INCORPORATION OF SULFATE INTO THE CAPSULAR POLYSACCHARIDE OF THE RED ALGA PORPHYRIDIUM

    Microsoft Academic Search

    J. Ramus; S. T. GROVES

    1972-01-01

    The accumulauon of sulfate-~sS by Porphyndzum aerug~neum cells and subsequent appearance of solubilized capsular polysaccharide-35S in the growth medium were examined The up- take of labeI by the cells was largely hght dependent. Pulse-chase experiments using log phase ceils revealed a iapid labeling of solubihzed capsular polysaccharide, recovered from the medium as the cetylpyridinium chloride precipitate Polyacwlamide gel electrophoresis of

  20. Inhibition of sulfate-reducing and methanogenic activities of anaerobic sewer biofilms by ferric iron dosing

    Microsoft Academic Search

    Lishan Zhang; Jürg Keller; Zhiguo Yuan

    2009-01-01

    Ferric iron is commonly used for sulfide precipitation in sewers, thus achieving corrosion and odour control. Its impact on the activities of sulfate-reducing bacteria and methanogens in anaerobic sewer biofilms is investigated in this study. Two lab-scale rising main sewer systems fed with real sewage were operated for 8 months. One received Fe3+ dosage (experimental system) and the other was

  1. Map Maker - Precipitation

    USGS Multimedia Gallery

    The National Atlas offered the Federal government's first on-line interactive Map Maker in 1997. A regional map of annual precipitation center on Oregon is shown. This image is simply a screen shot. Its source is listed below....

  2. Chemisorption And Precipitation Reactions

    EPA Science Inventory

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

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

    SciTech Connect

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

    1998-07-01

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

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

    Microsoft Academic Search

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

    2005-01-01

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

  5. 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

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

    2011-07-01

    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

  6. Integrated Spectroscopic Studies of Hydrous Sulfate Minerals

    NASA Technical Reports Server (NTRS)

    Dyar, M. D.; Lane, M. D.; Bishop, J. L.; OConnor, V.; Cloutis, E.; Hiroi, T.

    2005-01-01

    Sulfate minerals have been identified in Martian meteorites and on Mars using a suite of instruments aboard the MER rovers. These results have confirmed previous groundbased observations and orbital measurements that suggested their presence. The orbiting OMEGA instrument on Mars Express is also finding evidence for sulfate. In order to better interpret remote-sensing data, we present here the results of a coordinated visible/near infrared (VNIR) reflectance, Moussbauer (MB), and thermal emittance study of wellcharacterized hydrous sulfate minerals.

  7. Biotechnological Treatment of Sulfate-Rich Wastewaters

    Microsoft Academic Search

    P. N. L. Lens; A. Visser; A. J. H. Janssen; L. W. Hulshoff Pol; G. Lettinga

    1998-01-01

    Sulfate-rich wastewaters are generated by many industrial processes that use sulfuric acid or sulfate-rich feed stocks (e.g., fermentation or sea food processing industry). Also, the use of reduced sulfur compounds in industry, that is, sulfide (tanneries, kraft pulping), sulfite (sulfite pulping), or thiosulfate (pulp bleaching, fixing of photographs), contaminates wastewaters with sulfate. A major problem for the biological treatment of

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

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

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

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

    PubMed Central

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

    2011-01-01

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

  10. Functionalized synchrotron in-line phase-contrast computed tomography: a novel approach for simultaneous quantification of structural alterations and localization of barium-labelled alveolar macrophages within mouse lung samples.

    PubMed

    Dullin, Christian; dal Monego, Simeone; Larsson, Emanuel; Mohammadi, Sara; Krenkel, Martin; Garrovo, Chiara; Biffi, Stefania; Lorenzon, Andrea; Markus, Andrea; Napp, Joanna; Salditt, Tim; Accardo, Agostino; Alves, Frauke; Tromba, Giuliana

    2015-01-01

    Functionalized computed tomography (CT) in combination with labelled cells is virtually non-existent due to the limited sensitivity of X-ray-absorption-based imaging, but would be highly desirable to realise cell tracking studies in entire organisms. In this study we applied in-line free propagation X-ray phase-contrast CT (XPCT) in an allergic asthma mouse model to assess structural changes as well as the biodistribution of barium-labelled macrophages in lung tissue. Alveolar macrophages that were barium-sulfate-loaded and fluorescent-labelled were instilled intratracheally into asthmatic and control mice. Mice were sacrificed after 24 h, lungs were kept in situ, inflated with air and scanned utilizing XPCT at the SYRMEP beamline (Elettra Synchrotron Light Source, Italy). Single-distance phase retrieval was used to generate data sets with ten times greater contrast-to-noise ratio than absorption-based CT (in our setup), thus allowing to depict and quantify structural hallmarks of asthmatic lungs such as reduced air volume, obstruction of airways and increased soft-tissue content. Furthermore, we found a higher concentration as well as a specific accumulation of the barium-labelled macrophages in asthmatic lung tissue. It is believe that XPCT will be beneficial in preclinical asthma research for both the assessment of therapeutic response as well as the analysis of the role of the recruitment of macrophages to inflammatory sites. PMID:25537601

  11. Collapsin response mediator proteins of neonatal rat brain interact with chondroitin sulfate.

    PubMed

    Franken, Sebastian; Junghans, Ulrich; Rosslenbroich, Volker; Baader, Stephan L; Hoffmann, Ralf; Gieselmann, Volkmar; Viebahn, Christoph; Kappler, Joachim

    2003-01-31

    Chondroitin sulfate proteoglycans are structurally and functionally important components of the extracellular matrix of the central nervous system. Their expression in the developing mammalian brain is precisely regulated, and cell culture experiments implicate these proteoglycans in the control of cell adhesion, neuron migration, neurite formation, neuronal polarization, and neuron survival. Here, we report that a monoclonal antibody against chondroitin sulfate-binding proteins from neonatal rat brain recognizes collapsin response mediator protein-4 (CRMP-4), which belongs to a family of proteins involved in collapsin/semaphorin 3A signaling. Soluble CRMPs from neonatal rat brain bound to chondroitin sulfate affinity columns, and CRMP-specific antisera co-precipitated chondroitin sulfate. Moreover, chondroitin sulfate and CRMP-4 were found to be localized immuno-histochemically in overlapping distributions in the marginal zone and the subplate of the cerebral cortex. CRMPs are released to culture supernatants of NTera-2 precursor cells and of neocortical neurons after cell death, and CRMP-4 is strongly expressed in the upper cortical plate of neonatal rat where cell death is abundant. Therefore, naturally occurring cell death is a plausible mechanism that targets CRMPs to the extracellular matrix at certain stages of development. In summary, our data indicate that CRMPs, in addition to their role as cytosolic signal transduction molecules, may subserve as yet unknown functions in the developing brain as ligands of the extracellular matrix. PMID:12444086

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

    SciTech Connect

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

    2009-01-01

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

  13. Promotion of Ni2+ removal by masking toxicity to sulfate-reducing bacteria: addition of citrate.

    PubMed

    Qian, Junwei; Zhu, Xiaoyu; Tao, Yong; Zhou, Yan; He, Xiaohong; Li, Daping

    2015-01-01

    The sulfate-reducing bioprocess is a promising technology for the treatment of heavy metal-containing wastewater. This work was conducted to investigate the possibility of promoting heavy metal removal by the addition of citrate to mask Ni2+ toxicity to sulfate-reducing bacteria (SRB) in batch reactors. SRB growth was completely inhibited in Ni2+-containing medium (1 mM) when lactate served as the sole carbon resource, leading to no sulfate reduction and Ni2+ removal. However, after the addition of citrate, SRB grew well, and sulfate was quickly reduced to sulfide. Simultaneously, the Ni-citrate complex was biodegraded to Ni2+ and acetate. The NiS precipitate was then formed, and Ni2+ was completely removed from the solution. It was suggested that the addition of citrate greatly alleviates Ni2+ toxicity to SRB and improves the removal of Ni2+, which was confirmed by quantitative real-time PCR targeting dissimilatory sulfite reductase (dsrAB) genes. Analysis of the carbon metabolism indicated that lactate instead of acetate served as the electron donor for sulfate reduction. This study offers a potential approach to increase the removal of heavy metals from wastewater in the single stage SRB-based bioprocess. PMID:25860948

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

    E-print Network

    of magnesium sulfate. Characteristic and distinct Raman spectral patterns were observed for each of the 11 distinct hydrates of magnesium sulfates, crystalline and non-crystalline. The unique Raman spectral magnesium sulfates from the raw Raman spectra of mixtures. Using these Raman spectral features, we have

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

    Microsoft Academic Search

    Jinan Feng; Yuch Ping Hsieh

    1998-01-01

    Elevated sulfate and organic C loadings in freshwater wetlands could stimulate dissimilatory sulfate reduction that oxidizes organic C, produces hydrogen sulfide and alkalinity, and sequesters trace metals. The authors determined the extent of sulfate reduction in two freshwater wetland soils, that is black gum (Nyssa biflona) swamp soils and titi (Cliftonia monophylla) swamp soils, in northern Florida. They also investigated

  16. Barium geochemistry in sediment pore waters and formation waters of the oceanic crust on the eastern flank of the Juan de Fuca Ridge (ODP Leg 168)

    NASA Astrophysics Data System (ADS)

    Monnin, Christophe; Wheat, C. Geoffrey; Dupre, Bernard; Elderfield, Henry; Mottl, Mike M.

    2001-01-01

    Sediment pore waters collected on the eastern flank of the Juan de Fuca Ridge at 10 sites drilled during Ocean Drilling Program (ODP) Leg 168 and basement fluids discharging at the seafloor on a basaltic outcrop called Baby Bare located at ˜100 km east of the Juan de Fuca Ridge were analyzed for barium. The data show an overall symmetrical behavior between Ba and sulfate, suggesting that the pore water Ba content is controlled by equilibrium with barium sulfate. Barite saturation indices calculated with a thermodynamic model of the Na-K-Ca-Mg-Ba-Sr-Cl-SO4-H2O system show that barite does not equilibrate with the pore waters at the shipboard conditions (20°C, 1 bar) but reflects an overall equilibrium between pore waters and barite at in situ temperatures and pressures, for depths below ˜20 m below the seafloor. Barite supersaturation is found for conditions in the upper 20 m of the sediment column. Ba concentrations in pore waters at the base of the sediment section exceed those in the underlying formation fluids, based on the direct sampling of these fluids in the open borehole at ODP Sites 1026 and the hydrothermal springs at Baby Bare. This suggests that Ba is supplied to basement by the sediment. Despite this, the formation fluids are undersaturated with respect to barite. These fluids, which contain ˜2-3 times more Ba than bottom seawater, vent at the seafloor resulting in a net flux of Ba to bottom seawater. The calculated flux from warm (63°C) ridge flank hydrothermal systems is insignificant to the oceanic budget for Ba, but the flux associated from cool (less than 25°C) ridge flank hydrothermal systems, which dispense most of the heat and fluid flux through the oceanic crust, is unconstrained.

  17. Seawater sulfate reduction and sulfur isotope fractionation in basaltic systems: interaction of seawater with fayalite and magnetite at 200–350°C

    USGS Publications Warehouse

    Shanks, Wayne C., III; Bischoff, James L.; Rosenbauer, Robert J.

    1981-01-01

    Systematics of sulfur isotopes in the 250 and 350°C experiments indicate that isotopic equilibrium is reached, and can be modeled as a Rayleigh distillation process. Isotopic composition of hydrothermally produced H2S in natural systems is strongly dependent upon the seawater/basalt ratio in the geothermal system, which controls the relative sulfide contributions from the two important sulfur sources, seawater sulfate and sulfide phases in basalt. Anhydrite precipitation during geothermal heating severely limits sulfate ingress into high temperature interaction zones. Quantitative sulfate reduction can thus be accomplished without producing strongly oxidized rocks and resultant sulfide sulfur isotope values represent a mixture of seawater and basaltic sulfur.

  18. Acid Sulfate Weathering on Mars: Results from the Mars Exploration Rover Mission

    NASA Technical Reports Server (NTRS)

    Ming, Douglas W.; Morris, R. V.; Golden, D. C.

    2006-01-01

    Sulfur has played a major role in the formation and alteration of outcrops, rocks, and soils at the Mars Exploration Rover landing sites on Meridiani Planum and in Gusev crater. Jarosite, hematite, and evaporite sulfates (e.g., Mg and Ca sulfates) occur along with siliciclastic sediments in outcrops at Meridiani Planum. The occurrence of jarosite is a strong indicator for an acid sulfate weathering environment at Meridiani Planum. Some outcrops and rocks in the Columbia Hills in Gusev crater appear to be extensively altered as suggested by their relative softness as compared to crater floor basalts, high Fe(3+)/FeT, iron mineralogy dominated by nanophase Fe(3+) oxides, hematite and/or goethite, corundum-normative mineralogies, and the presence of Mg- and Casulfates. One scenario for aqueous alteration of these rocks and outcrops is that vapors and/or fluids rich in SO2 (volcanic source) and water interacted with rocks that were basaltic in bulk composition. Ferric-, Mg-, and Ca-sulfates, phosphates, and amorphous Si occur in several high albedo soils disturbed by the rover's wheels in the Columbia Hills. The mineralogy of these materials suggests the movement of liquid water within the host material and the subsequent evaporation of solutions rich in Fe, Mg, Ca, S, P, and Si. The presence of ferric sulfates suggests that these phases precipitated from highly oxidized, low-pH solutions. Several hypotheses that invoke acid sulfate weathering environments have been suggested for the aqueous formation of sulfate-bearing phases on the surface of Mars including (1) the oxidative weathering of ultramafic igneous rocks containing sulfides; (2) sulfuric acid weathering of basaltic materials by solutions enriched by volcanic gases (e.g., SO2); and (3) acid fog (i.e., vapors rich in H2SO4) weathering of basaltic or basaltic-derived materials.

  19. as the Strengthening Precipitates

    NASA Astrophysics Data System (ADS)

    Lu, Qi; Xu, Wei; van der Zwaag, Sybrand

    2014-12-01

    Generally, Laves phase and M23C6 are regarded as undesirable phases in creep-resistant steels due to their very high-coarsening rates and the resulting depletion of beneficial alloying elements from the matrix. In this study, a computational alloy design approach is presented to develop martensitic steels strengthened by Laves phase and/or M23C6, for which the coarsening rates are tailored such that they are at least one order of magnitude lower than those in existing alloys. Their volume fractions are optimized by tuning the chemical composition in parallel. The composition domain covering 10 alloying elements at realistic levels is searched by a genetic algorithm to explore the full potential of simultaneous maximization of the volume fraction and minimization of the precipitates coarsening rate. The calculations show that Co and W can drastically reduce the coarsening rate of Laves and M23C6 and yield high-volume fractions of precipitates. Mo on the other hand was shown to have a minimal effect on coarsening. The strengthening effects of Laves phase and M23C6 in the newly designed alloys are compared to existing counterparts, showing substantially higher precipitation-strengthening contributions especially after a long service time. New alloys were designed in which both Laves phase and M23C6 precipitates act as strengthening precipitates. Successfully combining MX and M23C6 was found to be impossible.

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

    Microsoft Academic Search

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

    1992-01-01

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

  1. Differential pulse anodic stripping voltammetry of barium and lead in gunshot residues

    Microsoft Academic Search

    Curt A. Woolever; Howard D. Dewald

    2001-01-01

    Differential pulse anodic stripping voltammetry (DPASV) has been applied for characterization and quantitative detection of barium and lead from gunshot residues (GSR). Previous electrochemical techniques have detected antimony and lead from GSR, however barium has never been detected. This technique allows for simultaneous detection of Ba and Pb that is simple, fast, and nondestructive.

  2. Electric fields and plasma waves resulting from a barium injection experiment

    Microsoft Academic Search

    H. C. Koons; Morris B. Pongratz

    1981-01-01

    A shaped-charge, barium plasma injection experiment was performed in June 1976 from the DOE Kauai test facility. The rocket payload contained seven shaped charges, a sevenfold larger package than the typical payloads employed in previous barium plasma injections conducted in this program. An attitude control system oriented the injection perpendicular to the local geomagnetic field. The injection altitude was 450

  3. Electron emitting barium-calcium aluminate obtained from chemical solution techniques

    Microsoft Academic Search

    C. Higashi; N. B. de Lima; J. R. Matos; C. Giovedi; C. C. Motta

    2005-01-01

    This paper reports a chemical technique to obtain barium-calcium aluminates used in impregnated thermionic cathodes. This procedure has been employed to improve the thermionic emission characteristics of the cathodes and to facilitate the preparation process of the emitting material. The crystallized powders were obtained using a mixed solution that contains barium, calcium, and aluminum in their chemical formula. Thermogravimetry and

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

    PubMed Central

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

    2015-01-01

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

  5. Vanadium doping effects on microstructure and dielectric properties of barium titanate ceramics

    Microsoft Academic Search

    Wei Cai; Chunlin Fu; Zebin Lin; Xiaoling Deng

    2011-01-01

    V-doped barium titante ceramics were prepared by conventional solid state reaction method. XRD patterns show that V5+ ions have entered into the tetragonal perovskite structure of solid solution to substitute for Ti4+ ions on the B sites. Addition of vanadium accelerates grain growth of BTO ceramics and there is abnormal grain growth of barium titanate ceramics with higher vanadium concentration.

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

    Microsoft Academic Search

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

    1997-01-01

    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

  7. Dielectric properties of MgO-doped compositionally graded multilayer barium strontium titanate films

    E-print Network

    Alpay, S. Pamir

    Dielectric properties of MgO-doped compositionally graded multilayer barium strontium titanate shifters and filters operat- ing in the microwave regime.1­4 Ferroelectrics FEs such as barium strontium in monolithic BST films especially with low strontium content, although the addition of MgO causes a reduction

  8. Impact of thermal strain on the dielectric constant of sputtered barium strontium titanate thin films

    E-print Network

    York, Robert A.

    Impact of thermal strain on the dielectric constant of sputtered barium strontium titanate thin, California 93106 Received 6 November 2001; accepted for publication 10 January 2002 Barium strontium titanate: magnesium oxide, strontium titanate, sapphire, silicon, and vycor glass. These substrates were chosen

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

    E-print Network

    Guo, John Zhanhu

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

  10. IEEE TRANSACTIONS ON MAGNETICS, VOL. 37, NO. 4, JULY 2001 2589 Barium and Strontium Ferrite Perpendicular Thin

    E-print Network

    Laughlin, David E.

    IEEE TRANSACTIONS ON MAGNETICS, VOL. 37, NO. 4, JULY 2001 2589 Barium and Strontium FerriteAlSi) as the soft magnetic underlayer for hexagonal barium ferrite (BaM) and strontium ferrite (SrM) was studied--Barium ferrite, multi-layer, sendust, soft under- layer, strontium ferrite, textured growth. I. INTRODUCTION M

  11. AlGaN/GaN metal-oxide-semiconductor heterostructure field-effect transistors using barium strontium titanate

    E-print Network

    York, Robert A.

    AlGaN/GaN metal-oxide-semiconductor heterostructure field-effect transistors using barium strontium-effect transistors have been formed by incorporating barium strontium titanate (BST) deposited by rf magnetron in increased leakage. Due to its large dielectric constant, barium strontium ti- tanate [Ba1-xSrxTiO3, (BST

  12. The effect of biaxial texture on the effective electromechanical constants of polycrystalline barium titanate and lead titanate thin films

    E-print Network

    Atwater, Harry

    barium titanate and lead titanate thin films Jennifer L. Ruglovsky a,*, Jiangyu Li b , Kaushik to an enhanced piezoelectric effect for barium titanate films, but not for lead titanate. Twist texturing about for a polycrystalline film. We explore tetragonal 4MM materials, and give specific results for barium titanate and lead

  13. Environmental monitoring of offshore oil and gas drilling discharges—A caution on the use of barium as a tracer

    Microsoft Academic Search

    John P. Hartley

    1996-01-01

    Commonly used methods for extracting barium from marine sediments are inefficient when high concentrations of barium sulphate are present in samples. Comparative data on sea-bed barium concentrations around a single exploration well are presented to highlight the influence of different extraction methods which can result in 2–3 order of magnitude differences in levels recorded. This suggests that in many monitoring

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

    PubMed Central

    Ren, Liyun; Kotha, Shiva P.

    2014-01-01

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

  15. Setting process of lime-based conservation mortars with barium hydroxide

    SciTech Connect

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

    2007-06-15

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

  16. Wideband and enhanced microwave absorption performance of doped barium ferrite

    NASA Astrophysics Data System (ADS)

    Meng, Pingyuan; Xiong, Kun; Ju, Kui; Li, Shengnan; Xu, Guangliang

    2015-07-01

    To achieve stronger microwave attenuation and larger bandwidth in electromagnetic absorber, the nickel ions (Ni2+) and manganese ions (Mn2+) were employed to partially replace the cobalt ions (Co2+) in BaCoTiFe10O19, and the doped barium hexaferrite (Ba(MnNi)0.2Co0.6TiFe10O19 and Ba(MnNi)0.25Co0.5TiFe10O19) powders were synthesized via the sol-gel combustion method. Subsequently, the microwave absorbing composites were prepared by mixing the ferrite powders with the paraffin. The X-ray diffraction (XRD) patterns of the doped ferrites confirmed the formation of the M-type barium ferrite, and no other types of barium ferrite could be found. Based on the electromagnetic parameters measured by the vector net-analyzer, it was found that the composite (Ba(MnNi)0.2Co0.6TiFe10O19) possessed a minimum reflection loss of -52.8 dB at 13.4 GHz with a matching thickness of 1.8 mm and the bandwidth below -15 dB was 5.8 GHz. Moreover, the maximum attenuation of Ba(MnNi)0.25Co0.5TiFe10O19 could reach -69 dB when its thickness was 1.8 mm, and also the bandwidth less than -20 dB was ranging from 13.2 GHz to 18 GHz. Thus, Ba(MnNi)0.2Co0.6TiFe10O19 and Ba(MnNi)0.25Co0.5TiFe10O19 could be the good microwave absorbers, which have great potentials to be applied in the high frequency fields of the microwave absorbing materials.

  17. Crystallization of Chicken Egg White Lysozyme from Assorted Sulfate Salts

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

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

  18. Temporal trends in the acidity of precipitation and surface waters of New York

    USGS Publications Warehouse

    Peters, Norman E.; Schroeder, Roy A.; Troutman, David E.

    1982-01-01

    Statistical analyses of precipitation data from a nine-station monitoring network indicate little change in pH from 1965-78 within New York State as a whole but suggest that pH of bulk precipitation has decreased in the western part of the State by approximately 0.2 pH units since 1965 and increased in the eastern part by a similar amount. This trend is equivalent to an annual change in hydrogen-ion concentration of 0.2 microequivalents per liter. An average annual increase in precipitation quantity of 2 to 3 percent since 1965 has resulted in an increased acid load in the western and central parts of the State. During 1965-78, sulfate concentration in precipitation decreased an average of 1-4 percent annually. In general, no trend in nitrate was detected. Calculated trends in hydrogen-ion concentration do not correlate with measured trends of sulfate and nitrate, which suggests variable neutralization of hydrogen ion, possibly by particles from dry deposition. Neutralization has produced an increase of about 0.3 pH units in nonurban areas and 0.7 pH units in urban areas. Statistical analyses of chemical data from several streams throughout New York suggest that sulfate concentrations decreased an average of 1 to 4 percent per year. This decrease is comparable to the sulfate decrease in precipitation during the same period. In most areas of the State, chemical contributions from urbanization and farming, as well as the neutralizing effect of carbonate soils, conceal whatever effects acid precipitation may have on pH of streams.

  19. Formation of a Precipitate

    NSDL National Science Digital Library

    2010-01-01

    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.

  20. A Geochemical and Mineralogical Model for Formation of Layered Sulfate Deposits at Meridiani Planum by Hydrothermal Acid-sulfate Alteration of Pyroclastic Basalt

    NASA Astrophysics Data System (ADS)

    McCollom, T. M.; Hynek, B. M.

    2012-12-01

    The Mars Exploration Rover (MER) Opportunity has extensively characterized sulfate-rich, hematite-bearing bedrock exposed at Meridiani Planum, Mars. Based on various measurements, the mineral composition of the bedrocks has been interpreted to include: amorphous silica/glass/phyllosilicates, Mg-, Ca-, and Fe-bearing sulfates including jarosite, minor amounts of igneous phases including plagioclase, pyroxene, olivine, and magnetite, and hematite [1,2]. Chemically, the bedrocks closely resemble the composition of pristine martian basalt with addition of S and O, and minor variations of Mg and Cl with depth [3,4]. Based on these and other observations, the MER team has proposed that the bedrocks represent chemically altered siliciclastic sediments combined with sulfate salts formed by evaporation of sulfate-bearing fluids, modified by transport and multiple stages of infiltrating groundwater [3,5]. Several alternative scenarios have been proposed for the origin of the rocks including large impacts [6], evaporating glacial deposits [7], acid-fog alteration [8], and hydrothermal acid-sulfate alteration of basalt [4]. In order to further evaluate the potential contribution of hydrothermal proceeses to the deposits, we performed numerical geochemical models of acid-sulfate alteration of martian basalt based on constraints provided by recent laboratory experiments. Experimental studies of alteration of basalt conducted in our lab [9] indicate that the initial stages of acid-sulfate alteration of pyroclastic basalt are characterized by rapid decomposition of igneous crystalline phases including plagioclase, pyroxene, and olivine, while the glass (and igneous phases protected within the glass) remain unreactive. Elements released by dissolving minerals are precipitated primarily as amorphous silica and Ca-, Al-, Fe- and Mg-bearing sulfates, while precipitation of phyllosilicates and Fe-oxides/oxyhydroxides (FeOx) is kinetically inhibited. Based on these constraints, models of acid-sulfate alteration of martian pyroclastic basalt predict that the early stages of alteration will produce amorphous silica, anhydrite (or gypsum at lower temperature), Fe-bearing natroalunite, and kieserite as predominant secondary phases, along with relict glass and silicates protected within the glass. Hematite may form with continued heating through partial decomposition of Fe-bearing natroalunite [9], and some of the glass phase may partially devitrify to form minor phyllosilicates such as nontronite and nanophase Fe oxides. The resulting rock would have a chemical and mineralogical composition closely resembling that observed at Meridiani Planum. We conclude that hydrothermal acid-sulfate alteration of pyroclastic basalt provides the most parsimonious explanation for the composition of the sulfate deposits. References: [1] Glotch et al., JGR (2006). [2] Klingelhöfer et al. Science (2004). [3] McLennan et al., EPSL (2005). [4] McCollom & Hynek, Nature (2005). [5] Squyres et al. Science (2006). [6] Knauth et al. Nature (2005). [7] Niles & Michalski, Nat. Geosci. (2009). [8] Berger et al. Am. Mineral. (2009). [9] McCollom et al. JGR-Planets (submitted ms.)

  1. 40 CFR 721.2420 - Alkoxylated dialkyldiethylenetriamine, alkyl sulfate salt.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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  2. 40 CFR 721.2420 - Alkoxylated dialkyldiethylenetriamine, alkyl sulfate salt.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

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  3. 40 CFR 721.2420 - Alkoxylated dialkyldiethylenetriamine, alkyl sulfate salt.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...dialkyldiethylenetriamine, alkyl sulfate salt. 721.2420 Section 721.2420 ...dialkyldiethylenetriamine, alkyl sulfate salt. (a) Chemical substance and significant...dialkyldiethylenetriamine, alkyl sulfate salt (PMN P-91-288) is subject to...

  4. 40 CFR 721.2420 - Alkoxylated dialkyldiethylenetriamine, alkyl sulfate salt.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...dialkyldiethylenetriamine, alkyl sulfate salt. 721.2420 Section 721.2420 ...dialkyldiethylenetriamine, alkyl sulfate salt. (a) Chemical substance and significant...dialkyldiethylenetriamine, alkyl sulfate salt (PMN P-91-288) is subject to...

  5. 40 CFR 721.2420 - Alkoxylated dialkyldiethylenetriamine, alkyl sulfate salt.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...dialkyldiethylenetriamine, alkyl sulfate salt. 721.2420 Section 721.2420 ...dialkyldiethylenetriamine, alkyl sulfate salt. (a) Chemical substance and significant...dialkyldiethylenetriamine, alkyl sulfate salt (PMN P-91-288) is subject to...

  6. 21 CFR 582.1127 - Aluminum ammonium sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Aluminum ammonium sulfate. 582.1127 Section...General Purpose Food Additives § 582.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate. (b) Conditions...

  7. 21 CFR 582.1131 - Aluminum sodium sulfate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

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  8. 21 CFR 582.1127 - Aluminum ammonium sulfate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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  9. 21 CFR 582.1127 - Aluminum ammonium sulfate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

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  10. 21 CFR 182.1127 - Aluminum ammonium sulfate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

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  11. 21 CFR 182.1127 - Aluminum ammonium sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

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  12. 21 CFR 182.1131 - Aluminum sodium sulfate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

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  13. 21 CFR 582.1127 - Aluminum ammonium sulfate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

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  14. 21 CFR 182.1129 - Aluminum potassium sulfate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

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  15. 21 CFR 182.1129 - Aluminum potassium sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

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  16. 21 CFR 182.1131 - Aluminum sodium sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

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  17. 21 CFR 582.1131 - Aluminum sodium sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

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  18. 21 CFR 182.1127 - Aluminum ammonium sulfate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

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  19. 21 CFR 182.1129 - Aluminum potassium sulfate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

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  20. 21 CFR 182.1127 - Aluminum ammonium sulfate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Aluminum ammonium sulfate. 182.1127 Section...Purpose GRAS Food Substances § 182.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate. (b) Conditions...

  1. 21 CFR 582.1131 - Aluminum sodium sulfate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

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

  2. 21 CFR 182.1131 - Aluminum sodium sulfate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Aluminum sodium sulfate. 182.1131 Section 182...Purpose GRAS Food Substances § 182.1131 Aluminum sodium sulfate. (a) Product. Aluminum sodium sulfate. (b) Conditions of...

  3. 21 CFR 182.1131 - Aluminum sodium sulfate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 2010-04-01 2009-04-01 true Aluminum sodium sulfate. 182.1131 Section 182...Purpose GRAS Food Substances § 182.1131 Aluminum sodium sulfate. (a) Product. Aluminum sodium sulfate. (b) Conditions of...

  4. 21 CFR 182.1127 - Aluminum ammonium sulfate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 2010-04-01 2009-04-01 true Aluminum ammonium sulfate. 182.1127 Section...Purpose GRAS Food Substances § 182.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate. (b) Conditions...

  5. 21 CFR 582.1127 - Aluminum ammonium sulfate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Aluminum ammonium sulfate. 582.1127 Section...General Purpose Food Additives § 582.1127 Aluminum ammonium sulfate. (a) Product. Aluminum ammonium sulfate. (b) Conditions...

  6. 21 CFR 582.1131 - Aluminum sodium sulfate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Aluminum sodium sulfate. 582.1131 Section 582...General Purpose Food Additives § 582.1131 Aluminum sodium sulfate. (a) Product. Aluminum sodium sulfate. (b) Conditions of...

  7. 21 CFR 182.1131 - Aluminum sodium sulfate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

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

  8. 21 CFR 182.1129 - Aluminum potassium sulfate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2012-04-01 false Aluminum potassium sulfate. 182.1129 Section...Purpose GRAS Food Substances § 182.1129 Aluminum potassium sulfate. (a) Product. Aluminum potassium sulfate. (b) Conditions...

  9. 21 CFR 582.1131 - Aluminum sodium sulfate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Aluminum sodium sulfate. 582.1131 Section 582...General Purpose Food Additives § 582.1131 Aluminum sodium sulfate. (a) Product. Aluminum sodium sulfate. (b) Conditions of...

  10. 21 CFR 522.1204 - Kanamycin sulfate injection.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Kanamycin sulfate injection. 522.1204...NEW ANIMAL DRUGS § 522.1204 Kanamycin sulfate injection. (a) Specifications . Each milliliter of kanamycin sulfate injection veterinary...

  11. 21 CFR 522.1204 - Kanamycin sulfate injection.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Kanamycin sulfate injection. 522.1204...NEW ANIMAL DRUGS § 522.1204 Kanamycin sulfate injection. (a) Specifications . Each milliliter of kanamycin sulfate injection veterinary...

  12. 21 CFR 520.1044a - Gentamicin sulfate oral solution.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

  13. 21 CFR 520.1044a - Gentamicin sulfate oral solution.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

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

  14. 21 CFR 522.62 - Aminopentamide hydrogen sulfate injection.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 false Aminopentamide hydrogen sulfate injection. 522.62 Section...ANIMAL DRUGS § 522.62 Aminopentamide hydrogen sulfate injection. (a) Chemical...Dimethylamino)-2,2-diphenylvaleramide hydrogen sulfate. (b)...

  15. Nanodielectric system for cryogenic applications: Barium titanate filled polyvinyl alcohol

    SciTech Connect

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

    2008-01-01

    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.

  16. The barium ion jet experiments of the Porcupine project

    NASA Astrophysics Data System (ADS)

    Haerendel, G.

    1980-06-01

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

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

    SciTech Connect

    Khassaf, H.; Khakpash, N. [Department of Materials Science and Engineering and Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269 (United States); Sun, F. [Department of Physics, University of Connecticut, Storrs, Connecticut 06269 (United States); Sbrockey, N. M.; Tompa, G. S. [Structured Materials Industries, Inc., Piscataway, New Jersey 08854 (United States); Kalkur, T. S. [Department of Electrical and Computer Engineering, University of Colorado at Colorado Springs, Colorado Springs, Colorado 80918 (United States); Alpay, S. P., E-mail: p.alpay@ims.uconn.edu [Department of Materials Science and Engineering and Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269 (United States); Department of Physics, University of Connecticut, Storrs, Connecticut 06269 (United States)

    2014-05-19

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  19. Dielectric behavior of barium modified strontium bismuth titanate ceramic

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

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

  20. Laser Raman Spectrum of Triglycine Sulfate

    Microsoft Academic Search

    Armen Galustian

    1973-01-01

    The laser Raman spectrum of ferroelectric triglycine sulfate has been determined by the use of an argon ion gas laser. The observed Raman lines are compared with reported assignments in the literature by Taurel and Krishnan, Determination of depolarization ratio of the sulfate line at 980 cm shows that the Raman band is highly polarizable and the molecular vibration is

  1. Sulfate induced heave in lime stabilized soil 

    E-print Network

    Bredenkamp, Sanet

    1994-01-01

    The addition of hydrated lime to clay soils is one of the most common methods of soil stabilization. However, when sulfates are present in the soil, the calcium in the lime reacts with the sulfates to form ettringite, an expandable mineral...

  2. Sulfate-reducing bacteria and their activities in oil production

    SciTech Connect

    Cord-Ruwisch, R.; Kleinitz, W.; Widdell, F.

    1987-01-01

    This paper presents an overview of the microbiology of sulfate-reducing bacteria (SRB) and their detrimental effects in oil technology and summarizes a study on SRB in an oil field. SRB are a group of specialized microorganisms that occur in aqueous environments in the absence of oxygen. The main nutrients for SRB are simple organic acids and molecular hydrogen (H/sub 2/) from decomposing natural organic matter. The nutrients are oxidized, with sulfate being reduced to sulfide (hydrogen sulfide, H/sub 2/S). The formed H/sub 2/S is the principal agent in the disastrous effects caused by SRB. It contaminates gas and stored oil, precipitates ferrous sulfide that plugs injection wells, and promotes corrosion of iron and steel in the absence of oxygen (anaerobic corrosion). Another principal mechanism by which SRB are involved in corrosion is their ability to depolarize iron surfaces by consumption of cathodically formed hydrogen. The postulate mechanisms in anaerobic corrosion are briefly explained. As an example for a microbiological study of SRB in oil technology, examination of an oil treater in a field in northern Germany is presented. On the basis of measured growth characteristics of the SRB, possibilities for controlling their activity are discussed.

  3. Passive abatement of acid rock drainage by sulfate reducing bacteria

    SciTech Connect

    Thompson, D.N.; Sayer, R.L.; Noah, K.S. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

    1996-10-01

    Passive treatment systems for Acid Rock Drainage (ARD) using wetland technology have been in development at eastern coal mines since the mid 1980s. Due to the high altitudes, remoteness, lack of large flat areas, and/or heavy metal levels at western mine sites, application of this technology has been lacking. This research explored whether pine sawdust can be used as sole carbon source in a smaller volume system for ARD remediation which can handle high throughputs. The technology utilizes sulfate reducing bacteria (SRB) to precipitate metal sulfides from their sulfates, while raising pH due to net consumption of H{sup +}. Laboratory results indicate that indigenous SRB are present in mud obtained from a northern Idaho mine site. With partially degraded lodgepole pine sawdust as carbon source, 50-99% reduction of various metals, and pH increases from 3 to about 7 were attained in ARD collected from mine seeps. Thus, this system appears promising as a long term, low cost/maintenance technology for ARD remediation at remote western mines.

  4. Gaseous Sulfate Solubility in Glass: Experimental Method

    SciTech Connect

    Bliss, Mary

    2013-11-30

    Sulfate solubility in glass is a key parameter in many commercial glasses and nuclear waste glasses. This report summarizes key publications specific to sulfate solubility experimental methods and the underlying physical chemistry calculations. The published methods and experimental data are used to verify the calculations in this report and are expanded to a range of current technical interest. The calculations and experimental methods described in this report will guide several experiments on sulfate solubility and saturation for the Hanford Waste Treatment Plant Enhanced Waste Glass Models effort. There are several tables of sulfate gas equilibrium values at high temperature to guide experimental gas mixing and to achieve desired SO3 levels. This report also describes the necessary equipment and best practices to perform sulfate saturation experiments for molten glasses. Results and findings will be published when experimental work is finished and this report is validated from the data obtained.

  5. Microbial sulfate reduction and metal attenuation in pH 4 acid mine water

    USGS Publications Warehouse

    Church, C.D.; Wilkin, R.T.; Alpers, C.N.; Rye, R.O.; Blaine, R.B.

    2007-01-01

    Sediments recovered from the flooded mine workings of the Penn Mine, a Cu-Zn mine abandoned since the early 1960s, were cultured for anaerobic bacteria over a range of pH (4.0 to 7.5). The molecular biology of sediments and cultures was studied to determine whether sulfate-reducing bacteria (SRB) were active in moderately acidic conditions present in the underground mine workings. Here we document multiple, independent analyses and show evidence that sulfate reduction and associated metal attenuation are occurring in the pH-4 mine environment. Water-chemistry analyses of the mine water reveal: (1) preferential complexation and precipitation by H2S of Cu and Cd, relative to Zn; (2) stable isotope ratios of 34S/32S and 18O/16O in dissolved SO4 that are 2-3 ??? heavier in the mine water, relative to those in surface waters; (3) reduction/oxidation conditions and dissolved gas concentrations consistent with conditions to support anaerobic processes such as sulfate reduction. Scanning electron microscope (SEM) analyses of sediment show 1.5-micrometer, spherical ZnS precipitates. Phospholipid fatty acid (PLFA) and denaturing gradient gel electrophoresis (DGGE) analyses of Penn Mine sediment show a high biomass level with a moderately diverse community structure composed primarily of iron- and sulfate-reducing bacteria. Cultures of sediment from the mine produced dissolved sulfide at pH values near 7 and near 4, forming precipitates of either iron sulfide or elemental sulfur. DGGE coupled with sequence and phylogenetic analysis of 16S rDNA gene segments showed populations of Desulfosporosinus and Desulfitobacterium in Penn Mine sediment and laboratory cultures. ?? 2007 Church et al; licensee BioMed Central Ltd.

  6. Microbial sulfate reduction and metal attenuation in pH 4 acid mine water

    PubMed Central

    Church, Clinton D; Wilkin, Richard T; Alpers, Charles N; Rye, Robert O; McCleskey, R Blaine

    2007-01-01

    Sediments recovered from the flooded mine workings of the Penn Mine, a Cu-Zn mine abandoned since the early 1960s, were cultured for anaerobic bacteria over a range of pH (4.0 to 7.5). The molecular biology of sediments and cultures was studied to determine whether sulfate-reducing bacteria (SRB) were active in moderately acidic conditions present in the underground mine workings. Here we document multiple, independent analyses and show evidence that sulfate reduction and associated metal attenuation are occurring in the pH-4 mine environment. Water-chemistry analyses of the mine water reveal: (1) preferential complexation and precipitation by H2S of Cu and Cd, relative to Zn; (2) stable isotope ratios of 34S/32S and 18O/16O in dissolved SO4 that are 2–3 ‰ heavier in the mine water, relative to those in surface waters; (3) reduction/oxidation conditions and dissolved gas concentrations consistent with conditions to support anaerobic processes such as sulfate reduction. Scanning electron microscope (SEM) analyses of sediment show 1.5-micrometer, spherical ZnS precipitates. Phospholipid fatty acid (PLFA) and denaturing gradient gel electrophoresis (DGGE) analyses of Penn Mine sediment show a high biomass level with a moderately diverse community structure composed primarily of iron- and sulfate-reducing bacteria. Cultures of sediment from the mine produced dissolved sulfide at pH values near 7 and near 4, forming precipitates of either iron sulfide or elemental sulfur. DGGE coupled with sequence and phylogenetic analysis of 16S rDNA gene segments showed populations of Desulfosporosinus and Desulfitobacterium in Penn Mine sediment and laboratory cultures. PMID:17956615

  7. Immunoaffinity centrifugal precipitation chromatography

    Microsoft Academic Search

    Lin Qi; Yoichiro Ito

    2007-01-01

    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

  8. Testing Precipitation Gage

    USGS Multimedia Gallery

    During August 2013, the Beaver Creek wildfire burned more than 114,000 acres near the south-central Idaho communities of Sun Valley, Ketchum, and Hailey. Partnering with Blaine County, the USGS installed a network of real-time precipitation gages in the burn area. Real-time information from the gage...

  9. 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...

  10. Installing Precipitation Gage

    USGS Multimedia Gallery

    During August 2013, the Beaver Creek wildfire burned more than 114,000 acres near the south-central Idaho communities of Sun Valley, Ketchum, and Hailey. Partnering with Blaine County, the USGS installed a network of real-time precipitation gages in the burn area. Real-time information from the gage...

  11. Total Precipitable Water

    SciTech Connect

    None

    2012-01-01

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

  12. Sulfation patterns of glycosaminoglycans encode molecular recognition and activity

    E-print Network

    Hsieh-Wilson, Linda

    to access homogeneous glycosaminoglycan structures. Here, we assembled well-defined chondroitin sulfate such an approach and provide evidence that chondroitin sulfate (CS) glycosaminoglycans encode functional

  13. Full-scale implementation of the sodium sulfide/ferrous sulfate treatment process. Final report, October 1987-March 1989

    SciTech Connect

    Beller, J.M.; Carpenter, G.S.; McAtee, R.E.; Pryfogle, P.A.; Suciu, D.F.

    1989-09-01

    In Phase I, jar and dynamic testing showed that the sodium sulfide/ferrous sulfate process was a viable method for reducing hexavalent chromium and removing heavy metals from the Tinker AFB industrial wastewater with a significant decrease in sludge production and treatment costs. In Phase II pilot-plant field verification studies were conducted to evaluate the chemical and physical parameters of the chromium reduction process, the precipitation and clarification process, and the activated sludge system. Sludge production was evaluated and compared to the sulfuric acid/sulfur dioxide/lime process. The impact of and procedure for change-over to the sodium sulfide/ferrous sulfate process were also investigated.

  14. Microbial Preservation in Sulfates in the Haughton Impact Structure Suggests Target in Search for Life on Mars

    NASA Technical Reports Server (NTRS)

    Parnell, J.; Osinski, G. R.; Lee, P.; Cockell, C. S.

    2005-01-01

    Microbes in Haughton Crater Sulfates: Impact craters are of high interest in planetary exploration because they are viewed as possible sites for evidence of life [1]. Hydrothermal systems in craters are particularly regarded as sites where primitive life could evolve. Evidence from the Miocene Haughton impact structure shows that crater hydrothermal deposits may also be a preferred site for subsequent colonization and hence possible extant life: Hydrothermal sulfates at Haughton are colonized by viable cyanobacteria [2]. The Haughton impact structure, Devon Island, Canadian High Arctic, is a 24 km-diameter crater of mid-Tertiary age. The structure preserves an exceptional record of impact-induced hydrothermal activity, including sulfide, and sulfate mineralization [3]. The target rocks excavated at the site included massive gypsum-bearing carbonate rocks of Ordovician age. Impact-remobilized sulfates occur as metre-scale masses of intergrown crystals of the clear form of gypsum selenite in veins and cavity fillings within the crater s impact melt breccia deposits [4]. The selenite is part of the hydrothermal assemblage as it was precipitated by cooling hot waters that were circulating as a result of the impact. Remobilization of the sulfate continues to the present day, such that it occurs in soil crusts (Fig. 1) including sandy beds with a gypsum cement. The sulfate-cemented beds make an interesting comparison with the sulfate-bearing sandy beds encountered by the Opportunity MER [5]. The selenite crystals are up to 0.3 m in width, of high purity, and transparent. They locally exhibit frayed margins where cleavage surfaces have separated. This exfoliation may be a response to freeze-thaw weathering. The selenite contains traces of rock detritus, newly precipitated gypsum, and microbial colonies. The rock detritus consists of sediment particles which penetrated the opened cleavages by up to 2cm from the crystal margins. Some of the detritus is cemented into place by gypsum, which must have been dissolved and reprecipitated from the host selenite.

  15. Evaluating enhanced sulfate reduction and optimized volatile fatty acids (VFA) composition in anaerobic reactor by Fe (III) addition.

    PubMed

    Liu, Yiwen; Zhang, Yaobin; Ni, Bing-Jie

    2015-02-17

    Anaerobic reactors with ferric iron addition have been experimentally demonstrated to be able to simultaneously improve sulfate reduction and organic matter degradation during sulfate-containing wastewater treatment. In this work, a mathematical model is developed to evaluate the impact of ferric iron addition on sulfate reduction and organic carbon removal as well as the volatile fatty acids (VFA) composition in anaerobic reactor. The model is successfully calibrated and validated using independent long-term experimental data sets from the anaerobic reactor with Fe (III) addition under different operational conditions. The model satisfactorily describes the sulfate reduction, organic carbon removal and VFA production. Results show Fe (III) addition induces the microbial reduction of Fe (III) by iron reducing bacteria (IRB), which significantly enhances sulfate reduction by sulfate reducing bacteria (SRB) and subsequently changes the VFA composition to acetate-dominating effluent. Simultaneously, the produced Fe (II) from IRB can alleviate the inhibition of undissociated H2S on microorganisms through iron sulfide precipitation, resulting in further improvement of the performance. In addition, the enhancement on reactor performance by Fe (III) is found to be more significantly favored at relatively low organic carbon/SO4(2-) ratio (e.g., 1.0) than at high organic carbon/SO4(2-) ratio (e.g., 4.5). The Fe (III)-based process of this work can be easily integrated with a commonly used strategy for phosphorus recovery, with the produced sulfide being recovered and then deposited into conventional chemical phosphorus removal sludge (FePO4) to achieve FeS precipitation for phosphorus recovery while the required Fe (III) being acquired from the waste ferric sludge of drinking water treatment process, to enable maximum resource recovery/reuse while achieving high-rate sulfate removal. PMID:25606811

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

    PubMed

    Jayaranjan, Madawala Liyanage Duminda; Annachhatre, Ajit P

    2013-01-01

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

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

    PubMed Central

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

    2013-01-01

    The development of new tools and devices to aid in treating cancer is a hot topic in biomedical research. The practice of using heat (hyperthermia) to treat cancerous lesions has a long history dating back to ancient Greece. With deeper knowledge of the factors that cause cancer and the transmissive window of cells and tissues in the near-infrared region of the electromagnetic spectrum, hyperthermia applications have been able to incorporate the use of lasers. Photothermal therapy has been introduced as a selective and noninvasive treatment for cancer, in which exogenous photothermal agents are exploited to achieve the selective destruction of cancer cells. In this manuscript, we propose applications of barium titanate core–gold shell nanoparticles for hyperthermia treatment against cancer cells. We explored the effect of increasing concentrations of these nanoshells (0–100 ?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

  18. The Global Precipitation Climatology Project (GPCP) Combined Precipitation Dataset

    Microsoft Academic Search

    George J. Huffman; Robert F. Adler; Philip Arkin; Alfred Chang; Ralph Ferraro; Arnold Gruber; John Janowiak; Alan McNab; Bruno Rudolf; Udo Schneider

    1997-01-01

    The Global Precipitation Climatology Project (GPCP) has released the GPCP Version 1 Combined Precipitation Data Set, a global, monthly precipitation dataset covering the period July 1987 through December 1995. The primary product in the dataset is a merged analysis incorporating precipitation estimates from low-orbit-satellite microwave data, geosynchronous-orbit-satellite infrared data, and rain gauge observations. The dataset also contains the individual input

  19. Liquid-Phase Processing of Barium Titanate Thin Films

    NASA Astrophysics Data System (ADS)

    Harris, David Thomas

    Processing of thin films introduces strict limits on the thermal budget due to substrate stability and thermal expansion mismatch stresses. Barium titanate serves as a model system for the difficulty in producing high quality thin films because of sensitivity to stress, scale, and crystal quality. Thermal budget restriction leads to reduced crystal quality, density, and grain growth, depressing ferroelectric and nonlinear dielectric properties. Processing of barium titanate is typically performed at temperatures hundreds of degrees above compatibility with metalized substrates. In particular integration with silicon and other low thermal expansion substrates is desirable for reductions in costs and wider availability of technologies. In bulk metal and ceramic systems, sintering behavior has been encouraged by the addition of a liquid forming second phase, improving kinetics and promoting densification and grain growth at lower temperatures. This approach is also widespread in the multilayer ceramic capacitor industry. However only limited exploration of flux processing with refractory thin films has been performed despite offering improved dielectric properties for barium titanate films at lower temperatures. This dissertation explores physical vapor deposition of barium titanate thin films with addition of liquid forming fluxes. Flux systems studied include BaO-B2O3, Bi2O3-BaB2O 4, BaO-V2O5, CuO-BaO-B2O3, and BaO-B2O3 modified by Al, Si, V, and Li. Additions of BaO-B2O3 leads to densification and an increase in average grain size from 50 nm to over 300 nm after annealing at 900 °C. The ability to tune permittivity of the material improved from 20% to 70%. Development of high quality films enables engineering of ferroelectric phase stability using residual thermal expansion mismatch in polycrystalline films. The observed shifts to TC match thermodynamic calculations, expected strain from the thermal expansion coefficients, as well as x-ray diffract measurements . Our system exhibits flux-film-substrate interactions that can lead to dramatic changes to the microstructure. This effect is especially pronounced onc -sapphire, with Al diffusion from the substrate leading to formation of an epitaxial BaAl2O4 second phase at the substrate-film interface. The formation of this second phase in the presence of a liquid phase seeds {111} twins that drive abnormal grain growth. The orientation of the sapphire substrate determines the BaAl2O 4 morphology, enabling control the abnormal grain growth behavior. CuO additions leads to significant grain growth at 900 °C, with average grain size approaching 500 nm. The orthorhombic-tetragonal phase transition is clearly observable in temperature dependent measurements and both linear and nonlinear dielectric properties are improved. All films containing CuO are susceptible to aging. A number of other systems were investigated for efficacy at temperatures below 900 °C. Pulsed laser deposition was used to study flux + BaTiO 3 targets, layered flux films, and in situ liquids. RF-magnetron sputtering using a dual-gun approach was used to explore integration on flexible foils with Ba1-xSrxTiO3. Many of these systems were based on the BaO-B2O3 system, which has proven effective in thin films, multilayer ceramic capacitors, and bulk ceramics. Modifiers allow tailoring of the microstructure at 900 °C, however no compositions were found, and no reports exist in the open literature, that provide significant grain growth or densification below 900 °C. Liquid phase fluxes offer a promising path forward for low temperature processing of barium titanate, with the ultimate goal of integration with metalized silicon substrates. This work demonstrates significant improvements to dielectric properties and the necessity of understanding interactions in the film-flux-substrate system.

  20. Precipitation Indices Low Countries

    NASA Astrophysics Data System (ADS)

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

    2009-09-01

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

  1. Benzene oxidation coupled to sulfate reduction

    USGS Publications Warehouse

    Lovley, D.R.; Coates, J.D.; Woodward, J.C.; Phillips, E.J.P.

    1995-01-01

    Highly reduced sediments from San Diego Bay, Calif., that were incubated under strictly anaerobic conditions metabolized benzene within 55 days when they were exposed initially to I ??M benzene. The rate of benzene metabolism increased as benzene was added back to the benzene-adapted sediments. When a [14C]benzene tracer was included with the benzene added to benzene-adapted sediments, 92% of the added radioactivity was recovered as 14CO2. Molybdate, an inhibitor of sulfate reduction, inhibited benzene uptake and production of 14CO2 from [14C]benzene. Benzene metabolism stopped when the sediments became sulfate depleted, and benzene uptake resumed when sulfate was added again. The stoichiometry of benzene uptake and sulfate reduction was consistent with the hypothesis that sulfate was the principal electron acceptor for benzene oxidation. Isotope trapping experiments performed with [14C]benzene revealed that there was no production of such potential extracellular intermediates of benzene oxidation as phenol, benzoate, p-hydroxybenzoate, cyclohexane, catechol, and acetate. The results demonstrate that benzene can be oxidized in the absence of O2, with sulfate serving as the electron acceptor, and suggest that some sulfate reducers are capable of completely oxidizing benzene to carbon dioxide without the production of extracellular intermediates. Although anaerobic benzene oxidation coupled to chelated Fe(III) has been documented previously, the study reported here provides the first example of a natural sediment compound that can serve as an electron acceptor for anaerobic benzene oxidation.

  2. Ion scattering spectroscopy studies of barium and oxygen on tungsten and tungsten-based dispenser cathodes

    NASA Astrophysics Data System (ADS)

    Marrian, C. R. K.; Shih, A.; Haas, G. A.

    1985-12-01

    In order to use Ion Scattering Spectroscopy (ISS) for studies of tungsten dispenser cathodes, the relevant ISS sensitivities must be measured. Calibrations have been made using a polycrystalline tungsten ribbon with controlled coverages of oxygen, barium and combinations thereof. Auger Electron Spectroscopy (AES) was used to monitor these controlled surfaces and the escape depths of the tungsten Auger electrons in barium and oxygen have been measured. The absolute ISS sensitivities of all three elements were found to be strongly dependent on the barium coverage of the tungsten surface. This effect has been attributed to the lowering of the work function of the tungsten surface caused by the barium adsorption. However, the relative ISS sensitivities of the three elements are not affected in this way when both barium and oxygen (or oxygen alone) are present on the tungsten surface. ISS spectra of such surfaces have been analyzed quantitatively and found to be in reasonable agreement with AES measurements. The analysis has also been applied to ISS spectra of uncoated tungsten matrix dispenser cathodes in an active state and following exposure to oxygen. Compared to AES, these spectra indicate less oxygen on the active cathode surfaces as a result of the oxygen (associated with barium) not contributing to the oxygen ISS signal. Comparisons of the spectra from the active and oxygen poisoned cathodes suggest that oxygen adsorbed during the oxygen exposure sits on the topmost barium layer whereas the oxygen on the active cathode surface does not.

  3. Anthropogenic Osmium in Precipitation

    NASA Astrophysics Data System (ADS)

    Chen, C.; Sedwick, P. N.; Sharma, M.

    2007-12-01

    Here we report the Os isotopic composition for precipitation from Hanover (NH), Soda Springs (CA) and the Ross Sea (Antarctica) as determined by negative thermal ionization mass spectrometry. All samples yielded non- radiogenic Os isotopic compositions. Snow and rain samples from Hanover, NH had Os concentrations of 0.8 - 12.2 fg/g (1 fg/g = 1E-15 g/g) and 187Os/188Os from 0.16 - 0.24. Snowpack from the high Sierra Nevada (Central Sierra Snow Laboratory, Soda Springs, CA) yielded Os concentration and isotopic composition of 3.6 fg/g and 0.21, respectively; Antarctic snow deposited above first year pack ice had [Os] = 0.8 fg/g and 187Os/188Os = 0.42. The isotopic ratios indicate that potential natural sources of Os to the atmosphere, such as continental mineral aerosols (187Os/188Os = 1.26) and seawater (187Os/188Os = 1.05) do not contribute bulk of Os to the precipitation. Instead, the isotopic ratios are identical to the platinum ores from the Merensky Reef in the Bushveld Igneous Complex, South Africa and Noril'sk Ni-Cu sulfide deposit associated with the Siberian Flood Basalts, Russia. These two deposits produce greater than 95 percent of the total Pt, Pd and Rh consumed annually primarily by the automotive industry. We infer that anthropogenic Os contribution dominates the isotopic composition of precipitation. The similar and non-radiogenic Os isotopic compositions observed in precipitation from disparate locations suggest that contamination of the troposphere with anthropogenic Os may be global in scale. We think that processing of ore to extract Pt, Pd, and Rh from PGE ores (PGE: group of six closely related elements Os, Ir, Pt, Pd, Rh, and Ru), which involves smelting and converting at high temperature and in the presence of oxygen, releases the volatile, toxic compound OsO4 into the troposphere, where it is mixed and then scavenged by precipitation, thus explaining both the non-radiogenic isotopic composition and the high and variable Os concentrations of Os in the precipitation. The magnitude of this contamination is likely sufficient to alter the global Os cycle and impact the isotopic composition of Os in the surface ocean.

  4. Studies of Sulfate Utilization by Algae

    PubMed Central

    Hodson, Robert C.; Schiff, Jerome A.; Mather, Jennie P.

    1971-01-01

    Seven mutants of Chlorella pyrenoidosa (Emerson strain 3) impaired for sulfate utilization have been isolated after treatment of the wild-type organism with nitrosoguanidine by replica plating on media containing thiosulfate and l-methionine. These mutants fall into three classes based on their ability to grow on sulfate, accumulate compounds labeled from sulfate-35S, and reduce adenosine 3?-phosphate 5?-phosphosulfate-35S (PAPS-35S) to thiosulfate-35S. Mutant Sat2? cannot grow on sulfate, but it accumulates thiosulfate-35S and homocysteic acid-35S from sulfate-35S in vivo. In addition, extracts of mutant Sat2? reduce PAPS-35S to thiosulfate-35S, indicating the possession of enzyme fractions S and A, both of which are required for thiosulfate formation. Mutants Sat1?, Sat3?, Sat4?, Sat5?, and Sat6? cannot grow on sulfate, and their extracts lack the ability to reduce PAPS-35S to thiosulfate-35S. Mutant Sat7?R1, a probable revertant, can grow on sulfate but still lacks the ability to reduce PAPS-35S to thiosulfate-35S in vitro. Complementation experiments in vitro show that the block in formation of acid-volatile radioactivity in every case is due to the absence of activity associated with fraction S. All mutants can grow on thiosulfate and all possess the activating enzymes which convert sulfate to PAPS. Through a comparison of nutritional and enzymatic characteristics, the first outlines of a branched and complicated pathway for sulfate reduction in Chlorella are beginning to emerge. PMID:16657613

  5. Heparan sulfate in skeletal muscle development

    SciTech Connect

    Noonan, D.M.

    1985-01-01

    In this study, chick breast skeletal muscle cells developing in vitro from myoblasts to myotubes were found to synthesize heparan sulfate (HS), chrondroitin-6-sulfate, chrondroitin-4-sulfate, dermatan sulfate, unsulfated chrondroitin and hyaluronic acid in both the substratum attached material (SAM) and the cellular fraction. SAM was found to contain predominantly chrondroitin-6-sulfate and relatively little HS whereas the cellular fraction contained relatively higher levels of HS and lower levels of chrondroitin-6-sulfate. Hyaluronic acid was also a major component in both fractions with the other glycosaminoglycan isomers present as minor components. Muscle derived fibroblast cultures had higher levels of dermatan sulfate in the cell layer and higher levels of HS in the SAM fraction than did muscle cultures. The structure of the proteoglycans were partially characterized in /sup 35/SO/sub 4//sup 2 -/ radio-labeled cultures which indicated an apparent increase in the hydrodynamic size of the cell fraction heparan sulfate proteoglycan (HS PG). Myotubes incorporated /sup 35/SO/sub 4//sup 2 -/ into HS PG at a rate 3 times higher than myoblasts. The turnover rate of HS in the cellular fraction was the same for myoblasts and myotubes, with a t/sub 1/2/ of approximately 5 hours. Fibroblasts in culture synthesized the smallest HS PG, and incorporated /sup 35/SO/sub 4//sup 2 -/ into HS PG at a rate lower than that of myotubes. Studies in which fusion was reversibly inhibited with decreased medium (Ca/sup + +/) closely linked the increased synthesis of cell fraction, but not SAM fraction, HS with myotube formation. However, decreasing medium calcium appeared to cause significant alterations in the metabolism of inorganic sulfate.

  6. Storm-wide precipitation retrievals

    E-print Network

    Loparo, Jessica A. (Jessica Ann), 1980-

    2004-01-01

    The monitoring of precipitation is important for scientific purposes, such as the study of world weather patterns, the development of global precipitation maps, and the tracking of seasonal and diurnal variations in ...

  7. Chlorate: a reversible inhibitor of proteoglycan sulfation

    SciTech Connect

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

    1988-07-15

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

  8. Sulfate attack in lime-treated subbases

    SciTech Connect

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

    1995-06-01

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

  9. Sulfate attack on hardened cement paste

    SciTech Connect

    Wang, J.G. (Shenzhen Univ. (China). Dept. of Applied Chemistry)

    1994-01-01

    Hardened cement paste specimens made with different cement types and varying water-cement ratios (w/c) were immersed in 5% sodium sulfate solution maintained at constant pH value of 6. The distribution curves for ettringite, gypsum, and portlandite phases were obtained by using layer by layer XRD analysis and interpreted in terms of material damage due to sulfate attack. The mechanism of sulfate attack is evaluated in regard to the leaching of Ca(OH)[sub 2] and formation of gypsum and ettringite.

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

  11. Leaching of /sup 226/Ra from U mill tailings by sulfate-reducing bacteria

    SciTech Connect

    Landa, E.R.; Miller, C.L.; Updegraff, D.M.

    1986-10-01

    Relatively insoluble sulfate precipitates appear to be a major host for Ra in sulfuric acid-treated, U mill tailings. The dissolution of such precipitates by natural processes, such as metabolism by sulfate-reducing bacteria (SRB), creates the potential for release of Ra to contacting waters. Significant leaching of Ra by SRB was achieved in the laboratory during the anaerobic incubation (1 to 119 days) of U mill tailings with pure cultures of Desulfovibrio desulfuricans and mixed cultures containing SRB isolated from the tailings, all grown on a lactate medium at room temperature. While the maximum /sup 226/Ra concentration reached in a sterile media control was 0.44 Bq/L (12 pCi/L), that in the SRB systems was 61 Bq/L (1640 pCi/L) or about 20% of the total Ra inventory in the original tailings sample. The leaching of Ra in SRB systems was accompanied by a decrease in soluble sulfate concentration, an increase in total sulfide concentration, and an increase in the number of SRB. The observed leaching effect does not appear to be due to the action of microbial chelates or to binding to cell walls. Potential implications of these findings to the management of U mill tailings and other radioactive wastes are discussed.

  12. Estimation of continental precipitation recycling

    Microsoft Academic Search

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

    1993-01-01

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

  13. Effects of Stratospheric Sulfate Geoengineering on Food Supply in China

    NASA Astrophysics Data System (ADS)

    Xia, L.; Robock, A.

    2010-12-01

    Possible food supply change is one of the most important concerns in the discussion of stratospheric geoengineering. In regions with high population density, climate changes such as precipitation reduction spurred by stratospheric sulfate injection may cause drought, reduce crop yield, and affect the food supply for hundreds of millions of people. Therefore, as part of the research into the benefits and risks of stratospheric geoengineering, it is necessary to fully investigate its effects on the regional climate system and crop yields, which is the goal of this study. In particular, we focus on China, not only because of its high risk to experience severe regional climate change after stratospheric geoengineering, but also because of its high vulnerability due to a large share of its population living on agriculture. To examine the effects of climate changes induced by geoengineering on Chinese agriculture, we use the DSSAT and CLICROP agricultural simulation models. We first evaluate these models by forcing them with daily weather data and management practices for the period 1978-2008 for all the provinces in China, and compare the results to observations of the yields of major crops in China (early season paddy, double crop paddy, spring wheat, winter wheat, corn, sorghum and soybean). Overall, there is a strong upward trend in both yield and fertilizer use, but interannual variations can be associated with temperature and precipitation variations. Using climate model simulations with the NASA GISS general circulation model forced by both a standard global warming scenario (A1B) and A1B combined with stratospheric geoengineering, we then apply scenarios of changes of precipitation and temperature from these runs to examine their effects on Chinese agricultural production. Compared to global warming only, the geoengineering runs produced summer precipitation reductions in northeastern China but precipitation increases in the Yangtze River region. Without changes of agricultural technology, stratospheric geoengineering reduces the yields and productions of major crops in China, especially northeastern China, where the frequency of drought increases. Fertilizer and irrigation both increase crop yields significantly. However, irrigation increases are more important than the fertilizer increases, because the irrigation system can efficiently redistribute water resources during drought and flood. In summary, agricultural technology (e.g., fertilizer and irrigation) largely compensates the effects of stratospheric geoengineering on Chinese agriculture, except in some extreme climate events.

  14. Hydrazine Sulfate–for health professionals (PDQ®)

    Cancer.gov

    Expert-reviewed information summary about the use of hydrazine sulfate as a treatment for people with cancer. Note: The information in this summary is no longer being updated and is provided for reference purposes only.

  15. 21 CFR 558.364 - Neomycin sulfate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

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

  16. 21 CFR 558.364 - Neomycin sulfate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

  17. Ferric sulfate montmorillonites as Mars soil analogs

    NASA Technical Reports Server (NTRS)

    Bishop, J. L.; Pieters, C. M.; Burns, R. G.

    1993-01-01

    Spectroscopic analyses have shown that Fe(3+)-doped smectites prepared in the laboratory exhibit important similarities to the soils on Mars. Ferrihydrite in these smectites has features in the visible to near-infrared region that resemble the energies and band-strengths of features in reflectance spectra observed for several bright regions on Mars. Ferric - sulfate - montmorillonite samples have been prepared more recently because they are a good compositional match with the surface material on Mars as measured by Viking. Reflectance spectra of montmorillonite doped with ferric sulfate in the interlayer regions include a strong 3 micron band that persists under dry conditions. This is in contrast to spectra of similarly prepared ferric-doped montmorillonites, which exhibit a relatively weaker 3 micron band under comparable dry environmental conditions. Presented here are reflectance spectra of a suite of ferric-sulfate exchanged montmorillonites prepared with variable ferric sulfate concentrations and variable pH conditions.

  18. Precipitation and Transformation of Secondary Fe Oxyhydroxides in a Histosol Impacted by Runoff from a Lead Smelter

    Microsoft Academic Search

    Xiaodong Gao; Darrell G. Schulze

    2010-01-01

    Secondary Fe(III) oxyhydroxides play a key role in controlling the mobility and bioavailability of trace metals in acidic, sulfate-rich soils, such as mining and smelter sites. Schwertmannite, jarosite, goethite, and ferrihydrite are the most common mineral phases identified in such soils. A good understanding of the precipitation and transformation of these minerals in soils is very important for predicting the

  19. Preparation of polyethylene sacks for collection of precipitation samples for chemical analysis

    USGS Publications Warehouse

    Schroder, L.J.; Bricker, A.W.

    1985-01-01

    Polyethylene sacks are used to collect precipitation samples. Washing polyethylene with acetone, hexane, methanol, or nitric acid can change the adsorptive characteristics of the polyethylene. In this study, simulated precipitation at pH 4.5 was in contact with the polyethylene sacks for 21 days; subsamples were removed for chemical analysis at 7, 14, and 21 days after intitial contact. Sacks washed with acetone adsorbed iron and lithium; sacks washed with hexane adsorbed barium, iron , and lithium; sacks washed with methanol adsorbed calcium and iron; and sacks washed with 0.30 N nitric acid adsorbed iron. Leaching the plastic sacks with 0.15 N nitric acid did not result in 100-percent recovery of any of the adsorbed metals. Washing polyethylene sacks with dilute nitric acid caused the pH of the simulated precipitation to be decreased by 0.2 pH unit after 1 week of contact with the polyethylene. The specific conductance increased by 10 microsiemens per centimeter. Contamination of precipitation samples by lead was determined to be about 0.1 microgram per liter from contact with precleaned polyethylene sacks. No measurable contamination of precipitation samples by zinc occurred. (USGS)

  20. Precipitation Estimates, Part 1: Measurement

    NSDL National Science Digital Library

    COMET

    2009-06-03

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

  1. Climate forcing by carbonaceous and sulfate aerosols

    Microsoft Academic Search

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

    1998-01-01

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

  2. Supported sulfated zirconia catalysts and their properties

    Microsoft Academic Search

    Hillary A. Prescott; Martin Wloka; Erhard Kemnitz

    2004-01-01

    Sulfated zirconia (SZ), SO4\\/ZrO2, was supported by SiO2, ?-Al2O3, and K-10. Aspects of preparation, such as ZrO2 precursor, sulfur contents, sulfating agent, and calcination conditions, were studied. The pure supports and catalysts were characterized with XRD, BET, FTIR photoacoustic spectroscopy (pyridine adsorption), NH3-TPD, and tested for the benzoylation of anisole with benzoyl chloride. The support strongly affects the catalytic activity;

  3. Sulfation in lead–acid batteries

    Microsoft Academic Search

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

    2004-01-01

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

  4. Plant sulfate assimilation genes: redundancy versus specialization

    Microsoft Academic Search

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

    2009-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Lazaroff, Norman; Jollie, John; Dugan, Patrick R.

    1998-07-01

    Chemolithotrophic iron oxidation by Thiobacillus ferrooxidans and other iron oxidizing thiobacilli produce an Fe(III) sulfato complex that polymerizes as x-ray amorphous filaments approximately 40 nm in diameter. The precursor complex in solutionis seen by ATR-FTIR spectroscopy to have a sulfate spectrum resembling the v(subscript 3) and v(subscript 1) vibrational modes of the precipitated polymer. Chemically similar precipitates prepared by oxidation of acid ferrous sulfate with hydrogen peroxide have a different micromorphology, higher iron/sulfur ratio and acid solubility than the bacterial product. They possess coalescing globular microstructures composed of compacted micro-fibrils. Scanning electron microscopy and diffuse reflectance FTIR show the formation of iron polymer on the surface of immobilized cells of T. ferrooxidans, oxidizing iron during the corrosion of steel. Although spatially separated form the steel coupons by a membrane filter, the cell walls become covered with tufts of amorphous hydrated Fe(III) sulfate. The metastable polymer is converted to crystalline goethite, lepidocrocite, and magnetite in that order, as the pH rises due to proton reduction at cathodic sites on the steel. The instability of the iron polymer to changes in pH is also evidenced by the loss of sulfate when washed with lithium hydroxide solution at pH 8. Under those conditions there is little change in micromorphology, but restoration of sulfate with sulfuric acid at pH 2.5, fails to re-establish the original chemical structure. Adding sulfate salts of appropriate cations to solutions of the Fe(III) sulfato complex or suspensions of its precipitated polymer in dilute sulfuric acid, result in dissociation of the metastable complex followed by crystallization of ferric ions and sulfate in jarosites. Jarosites and other derivatives of iron precipitation by iron oxidizing thiobacilli, form conspicuous deposits in areas of natural pyrite leaching. The role of iron oxidizing thiobacilli in pyrite leaching, biohydrometallurgy, acid mine drainage, and the cycle of iron and sulfur in nature, has been studied for nearly 50 years. The manifestation of those activities, so widespread on Earth, can be a clue for seeking evidence of life elsewhere.

  6. Phase structures and stability in barium titanate ferroelectric ultrathin films

    NASA Astrophysics Data System (ADS)

    Zhang, Jian; Yin, Zhen; Zhang, Ming-Sheng

    2003-04-01

    Under taking into account both stress and surface effects, an extended Landau-Devonshire theory is developed to investigate the phase structures and ferroelectric stability in barium titanate ultrathin films. The phase diagrams of temperature-stress, film thickness-stress and polarization-film thickness are calculated. For the surface polarization smaller than the bulk, the paraelectric phase starts at temperature below the bulk Curie temperature under small stresses and the ferroelectric phases can be stabilized in the ultrathin films under large stresses. For the surface polarization larger than the bulk, the paraelectric phase appears at temperature above the bulk Curie temperature and the ferroelectricity can be sustained in the ultrathin films by the “superpolarized” surface layer.

  7. Coralline barium records temporal variability in equatorial Pacific upwelling

    NASA Astrophysics Data System (ADS)

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

    1989-08-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

  9. Barium titanate nanocomposite capacitor FY09 year end report.

    SciTech Connect

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

    2009-11-01

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

  10. Barium strontium oxide coated carbon nanotubes as field emitters

    NASA Astrophysics Data System (ADS)

    Jin, Feng; Liu, Yan; Day, Christopher M.

    2007-04-01

    The authors report a field emitter structure based on oxide coated carbon nanotubes (CNTs). This emitter consists of a thin tungsten ribbon with CNTs on the surface and a thin layer of low work function barium strontium oxide coating on the CNTs. This oxide coated CNT emitter was designed to combine the benefits of the high field enhancement factor from CNTs and the low work function from the emissive oxide coating. The field emission properties of the emitters were characterized. A field enhancement factor of 467 and a work function of 1.9eV were obtained for the oxide coated CNTs. Compared to the uncoated CNTs, the field emission from the oxide coated CNTs increased by a factor of 2-3. At 4.4V/?m, the field emission current of 23.6?A was obtained from an emitting surface of 0.012cm2.

  11. Impact of vanadium ions in barium borate glass

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

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

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaohang; Drabbels, Marcel

    2012-08-01

    The solvation of Ba+ ions created by the photoionization of barium atoms located on the surface of helium nanodroplets has been investigated. The excitation spectra corresponding to the 6p 2P1/2 ? 6s 2S1/2 and 6p 2P3/2 ? 6s 2S1/2 transitions of Ba+ are found to be identical to those recorded in bulk He II [H. J. Reyher, H. Bauer, C. Huber, R. Mayer, A. Schafer, and A. Winnacker, Phys. Lett. A 115, 238 (1986)], indicating that the ions formed at the surface of the helium droplets become fully solvated by the helium. Time-of-flight mass spectra suggest that following the excitation of the solvated Ba+ ions, these are being ejected from the helium droplets either as bare Ba+ ions or as small Ba+Hen (n < 20) complexes.

  13. Conoscopic study of strontium-barium niobate single crystals

    NASA Astrophysics Data System (ADS)

    Kolesnikov, Aleksandr; Grechishkin, Rostislav; Malyshkina, Olga; Malyshkin, Yury; Dec, Jan; ?ukasiewicz, Tadeusz; Ivanova, Aleksandra

    2013-12-01

    Optically transparent single crystals of strontium-barium niobate, SrxBa1-xNb2O6, of different compositions (x = 0.26...0.7) were examined with the aid of conoscopic light interference figures. A regular change of the isochrome concentric ring number and diameters consistent with the temperature variation of the value of birefringence is demonstrated by direct observations of polar cuts of optically uniaxial samples. Anomalous violations of the conventional (uniaxial) interference patterns occur occasionaly in some samples being indicative of the existence of biaxial trait in their behaviour even though no voltage is applied. These features may depend on annealing treatments at elevated temperatures. The results of the study show that conoscopic images may serve as a sensitive indicator of the structural state of SBN crystals related to the effects of stress-induced change of optical anisotropy and temperature dependent birefringence parameters.

  14. Supercritical fluid route for synthesizing crystalline Barium Strontium Titanate nanoparticles.

    PubMed

    Reverón, H; Elissalde, C; Aymonier, C; Bidault, O; Maglione, M; Cansell, F

    2005-10-01

    Pure and well-crystallized Barium Strontium Titanate (BST) nanoparticles with controlled Ba/Sr ratio have been successfully synthesized under supercritical conditions using a continuous-flow reactor in the temperature range of 150-380 degrees C at 26 MPa. To synthesize the Ba0.6Sr0.4TiO3 composition, alkoxides, ethanol and water were used. The resulting nanopowder consists of fine particles with an average particle size of 23 nm. The results show that the Ba/Sr ratio of this powder can be accurately controlled from the composition of precursor. The characterization of the as-synthesized Ba0.6Sr0.4TiO3 solid-solution and the dielectric properties of the sintered ceramics are here reported. PMID:16245539

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

  16. Renal handling of phosphate and sulfate.

    PubMed

    Biber, J; Murer, H; Mohebbi, N; Wagner, C A

    2014-04-01

    In the kidney, both anions, phosphate and sulfate, are almost freely filtered and afterwards reclaimed (reabsorbed) to a large extent from tubular fluid along the proximal tubules. Under normal dietary conditions, fractional excretion of these anions is approximately 10%. Reabsorption of both anions occurs along the proximal tubules by active, saturable, and regulated transepithelial processes. Most of the transporters involved in renal handling of phosphate and sulfate have been identified and their transport functions as well as their cellular localizations have been described in detail. The role of these transporters in the renal handling of phosphate and sulfate has been investigated by the use of several mice knock out models and also by analysis of several inherited human diseases. Numerous hormonal and nonhormonal factors, have been described that alter renal excretion of phosphate or sulfate by mechanisms that alter the abundance of known phosphate/sulfate transporters and consequently renal excretion. These mechanisms contribute to the homeostasis of the extracellular concentrations of phosphate and sulfate. PMID:24715567

  17. Remedial actions for acidic sulfate corrosion

    SciTech Connect

    Baum, A.J. (Westinghouse Electric Corp., Pittsburgh, PA (United States). Nuclear Services Div.)

    1992-08-01

    Objectives were to identify a reference acid sulfate environment which produced accelerated intergranular corrosion of Alloy 600 tubing under typical steam generator operating conditions and to identify inhibitors capable of limiting the progression of the corrosion. A background report summarized the occurrences of corrosion in operating steam generators attributed to acid sulfate environments and reviewed the laboratory corrosion tests performed in these environments. Although the corrosion in several operating plants is thought to be caused by acid sulfate environments, and previous laboratory testing his produced corrosion of Alloy 600 tubing in the presence of acid sulfates, the testing performed in this program did not produce accelerated intergranular corrosion. In some cases, the tests produced accelerated localized wastage, but this is not representative of the most relevant plant experience. Testing with more oxidizing conditions was found to reduce the aggressiveness of the corrosion. Given the range of test conditions addressed in the testing, it is concluded that the occurrence of intergranular corrosion with acid sulfate bulk chemistries is confined to a narrower range of operating variables than is typically thought to be the case for intergranular corrosion produced in alkaline environments. Zinc oxide and homologous and substituted derivatives of ethylene-diamine and propylene-diamine were identified as candidate inhibitors for acid sulfate-induced corrosion. They may also have corrosion inhibition capabilities in other crevice environments.

  18. Deriving a History of Deposition and Alteration from Phyllosilicate-Sulfate Associations at Gale Crater

    NASA Astrophysics Data System (ADS)

    Vaniman, D. T.

    2011-12-01

    Gale Crater, field site for the 2011 Mars Science Laboratory rover Curiosity, is located in one of the most chlorine- and sulfur-rich areas detected by Odyssey gamma-ray spectroscopy (GRS) along the dichotomy boundary between Mars' southern cratered highlands and the northern plains. Comparably elevated chlorine and sulfur abundances occur in Arabia Terra, where modeling and MER Opportunity observations suggest that groundwater upwelling led to evaporite salt precipitation. In a deep crater such as Gale upwelling may have produced playa systems. High GRS sulfur at Gale Crater is supported by visible-infrared spectra in Gale's central mound consistent with Mg-sulfates (kieserite and polyhydrated), interstratified with smectite. There is a significant (~20 m) section with abundant nontronite and little or no evidence of hydrated sulfate in the lower mound. Mineral stratification at Gale promises the possibility of capturing a transition in sedimentary environment between phyllosilicate- and sulfate-dominated deposition. Sedimentary fabrics, textures, and mineralogy all bear on determining sedimentary history and Gale will provide an exceptionally detailed history through Curiosity's instrument suite. Should the clay minerals at Gale be limited to nontronite and other smectites, with little evidence of chlorite or mixed layer chlorite/smectite, limits can be placed on the extent of interaction with Mg-sulfate solutions. Gale has evidence of being at one time completely filled and a lack of chloritic forms would be particularly limiting on occurrence and composition of paleo-groundwater. Complete infilling of Gale would likely result in past burial temperatures, at the deep elevation of the landing site, favoring chloritization of smectite if concentrated Mg-sulfate groundwater were present. Sedimentary history at Gale may be further constrained by absence or presence of Ca-sulfates, which should form by cation exchange between smectite and Mg-enriched brines if the two were in communication. Since Mg-sulfate solutions are implicated by presence of Mg-sulfates at Gale, absence or presence of Ca-sulfates may be a measure of hydrologic isolation or interaction, respectively, within and between stratigraphic horizons. The forms in which Ca-sulfates may occur (gypsum, bassanite, or anhydrite) would provide further constraints on Gale's history of deposition and alteration. The high solubility of Mg-sulfates can also place limits on interpretations of post-depositional alteration by groundwater, wherein preservation of primary depositional structure, fabric, and mineralogy will be an especially sensitive marker of deposits undisturbed by such alteration. Groundwater, snowmelt, and surface water are all capable of attacking Mg-sulfate (and potential halide) deposits at Gale but so too will elevated water vapor pressure that may lead to deliquescence or efflorescence, effects that may be expected if episodes of high obliquity allowed prolonged frost or ice accumulation in Gale Crater. Among the concerns of Curiosity will be identification and sampling of sedimentary strata that are as pristine as possible. The sensitivity of phyllosilicate-sulfate associations to transformation promises that evidence of alteration will be identifiable.

  19. Sulfite exchange dominates oxygen isotope compositions of sulfate produced from abiotic pyrite oxidation

    NASA Astrophysics Data System (ADS)

    Kohl, I. E.; Bao, H.

    2009-12-01

    The oxidation of reduced sulfur compounds (solid, liquid and gas phase) is of primary importance when attempting to understand the global sulfur and oxygen cycles as preserved in sulfate minerals. It has long been known that O2, H2O, and Fe3+ all play an important role during this oxidation process, especially during the oxidation of sulfide minerals. The exact role of each oxidant and/or oxygen source has yet to be experimentally determined for oxidation in aqueous solutions over a range of pH values. In addition, the reported air O2 signal being incorporated in product sulfate appears to be highly variable (9-60%), which could be due to the presence of multiple oxidation pathways or the inability of the traditional ?18O label to differentiate kinetic effects on the degree of oxygen exchange. Here we test the affect of pH dependent sulfite-water oxygen exchange rate and precipitation of ferric hydroxides on the produced sulfate’s O2/H2O ratio. Our experiments utilize a ?17O isotope label in the solutions, enabling a quantitative determination of oxygen source ratios (O2 vs. H2O) in the produced sulfate. We oxidized crushed pyrite grains aerobically in sterile, buffered solutions at pH=2,7,9,10, and 11. A duplicate set was spiked with Fe3+. The results from the reactors indicate that despite the pH dependency of sulfite-water exchange rate, fast at low pH and slow at high pH, the stability of intermediates, thiosulfate and especially sulfite, in alkaline solutions allows the exchange to proceed to equilibrium. This resulted in sulfate produced above pH=9 to contain 21-24% air O2 signal, indicating the last oxidation step, producing sulfate from sulfite, proceeded with direct incorporation of dissolved air O2 as represented by equation (1). The role of Fe3+ under alkaline conditions was observed to be negligible. SO32- + 1/2O2 ? SO42- (1) In the pH=2 reactor, the O2% in the produced sulfate was 21% with the addition of Fe3+, but was 28-29% without the Fe3+ addition. A similar ~25% O2 signal is measured for sulfate produced in circum-neutral solutions. These results indicate that sulfite-water oxygen exchange determines the O2 signal in sulfate produced from oxidation of pyrite for all pH conditions examined. In alkaline conditions, although the exchange rate of sulfur-oxyanion species with water is slow, their stability in solution offsets the low exchange rate. The final oxidation of sulfite to sulfate as depicted by reaction (1) results in a consistent O2% (21-29) incorporation in sulfate. Our results suggest that abiotic oxidative weathering of pyrite produces sulfate with 25±4% air O2 oxygen, a much smaller range than previously proposed with the use of ?18O labels. This provides important constraints on pyrite oxidation mechanisms and interpreting the anomalous 17O signals found in Marinoan barite (BaSO4) deposits, which are believed to come from atmospheric O2 at a time when global glaciation resulted in unique atmospheric conditions.

  20. Raman scattering study of barium borate glasses and melts

    NASA Astrophysics Data System (ADS)

    Osipov, Armenak A.; Osipova, Leyla M.

    2013-07-01

    Glasses and melts of xBaO-(100-x)B2O3 (x=20, 25, 30, 35, 40, 45, 50, 55, 60 and 67 mol%) composition have been prepared and studied using high-temperature Raman spectroscopy. It was shown that the structure of the glassy and molten samples with relatively low concentrations of barium oxide (x=20-35 mol%) consists of [B?4]- charged tetrahedra (? is a bridging oxygen atom), B?2O- asymmetric triangles (O- is a non-bridging oxygen atom) and B?3 neutral units. The concentration of [B?4]- tetrahedra (N4) monotonously decreases with increasing BaO content in the melts structure, whereas N4 demonstrates a maximum at x?40 mol% in the glassy samples. B?O22- pyroborate units appear at x?40 mol%, and BO33- orthoborate anions are also formed in the melts structure when x=60 and 67 mol%. The dominant mechanisms for the structural reorganizations generated by changes in temperature depend on the melt composition. The changes in the short range order (SRO) structures can be described by the [B?4]-?B?2O- isomerization reaction at 2550 is most likely described by the 2B?2O?B?O22-+B?3 disproportionation reaction. In both cases, the equilibrium shifts to the right with an increase in temperature. Significant changes in the local structures of melts with a low concentration of barium oxide (x?20 mol%) were not found.

  1. 21 CFR 524.154 - Bacitracin or bacitracin zinc-neomycin sulfate-polymyxin B sulfate ophthalmic ointment.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 false Bacitracin or bacitracin zinc-neomycin sulfate-polymyxin B sulfate... § 524.154 Bacitracin or bacitracin zinc-neomycin sulfate-polymyxin B sulfate...each gram contains 400 units of bacitracin zinc, 3.5 milligrams of neomycin, and...

  2. 21 CFR 524.155 - Bacitracin zinc-polymyxin B sulfate-neomycin sulfate-hydrocortisone or hydrocortisone acetate...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Bacitracin zinc-polymyxin B sulfate-neomycin sulfate-hydrocortisone...ANIMAL DRUGS § 524.155 Bacitracin zinc-polymyxin B sulfate-neomycin sulfate-hydrocortisone...ointment contains 400 units of bacitracin zinc, 10,000 units of polymyxin B...

  3. 21 CFR 524.154 - Bacitracin or bacitracin zinc-neomycin sulfate-polymyxin B sulfate ophthalmic ointment.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 false Bacitracin or bacitracin zinc-neomycin sulfate-polymyxin B sulfate... § 524.154 Bacitracin or bacitracin zinc-neomycin sulfate-polymyxin B sulfate...each gram contains 400 units of bacitracin zinc, 3.5 milligrams of neomycin, and...

  4. 21 CFR 524.154 - Bacitracin or bacitracin zinc-neomycin sulfate-polymyxin B sulfate ophthalmic ointment.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 false Bacitracin or bacitracin zinc-neomycin sulfate-polymyxin B sulfate... § 524.154 Bacitracin or bacitracin zinc-neomycin sulfate-polymyxin B sulfate...each gram contains 400 units of bacitracin zinc, 3.5 milligrams of neomycin, and...

  5. Use of Bisacodyl in Preparation of the Bowels for a Barium Enema

    Microsoft Academic Search

    J. G. Sowerbutts

    1960-01-01

    This account of a new and successful technique in preparing patients for a barium enema examination will interest clinicians, for its eventual adoption by radiologists would greatly reduce the discomfort of this invaluable but disagreeable investigation.

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

    NASA Technical Reports Server (NTRS)

    Swift, D. W.

    1985-01-01

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

  7. Chronic barium intoxication disrupts sulphated proteoglycan synthesis: a hypothesis for the origins of multiple sclerosis.

    PubMed

    Purdey, Mark

    2004-01-01

    High level contamination by natural and industrial sources of the alkali earth metal, barium (Ba) has been identified in the ecosystems/workplaces that are associated with high incidence clustering of multiple sclerosis (MS) and other neurodegenerative diseases such as the transmissible spongiform encephalopathies (TSEs) and amyotrophic lateral sclerosis (ALS). Analyses of ecosystems supporting the most renowned MS clusters in Saskatchewan, Sardinia, Massachusetts, Colorado, Guam, NE Scotland demonstrated consistently elevated levels of Ba in soils (mean: 1428 ppm) and vegetation (mean: 74 ppm) in relation to mean levels of 345 and 19 ppm recorded in MS-free regions adjoining. The high levels of Ba stemmed from local quarrying for Ba ores and/or use of Ba in paper/foundry/welding/textile/oil and gas well related industries, as well as from the use of Ba as an atmospheric aerosol spray for enhancing/refracting the signalling of radio/radar waves along military jet flight paths, missile test ranges, etc. It is proposed that chronic contamination of the biosystem with the reactive types of Ba salts can initiate the pathogenesis of MS; due to the conjugation of Ba with free sulphate, which subsequently deprives the endogenous sulphated proteoglycan molecules (heparan sulfates) of their sulphate co partner, thereby disrupting synthesis of S-proteoglycans and their crucial role in the fibroblast growth factor (FGF) signalling which induces oligodendrocyte progenitors to maintain the growth and structural integrity of the myelin sheath. Loss of S-proteoglycan activity explains other key facets of MS pathogenesis; such as the aggregation of platelets and the proliferation of superoxide generated oxidative stress. Ba intoxications disturb the sodium-potassium ion pump--another key feature of the MS profile. The co-clustering of various neurodegenerative diseases in these Ba-contaminated ecosystems suggests that the pathogenesis of all of these diseases could pivot upon a common disruption of the sulphated proteoglycan-growth factor mediated signalling systems. Individual genetics dictates which specific disease emerges at the end of the day. PMID:15082100

  8. Sulfate reduction at low pH to remediate acid mine drainage.

    PubMed

    Sánchez-Andrea, Irene; Sanz, Jose Luis; Bijmans, Martijn F M; Stams, Alfons J M

    2014-03-30

    Industrial activities and the natural oxidation of metallic sulfide-ores produce sulfate-rich waters with low pH and high heavy metals content, generally termed acid mine drainage (AMD). This is of great environmental concern as some heavy metals are highly toxic. Within a number of possibilities, biological treatment applying sulfate-reducing bacteria (SRB) is an attractive option to treat AMD and to recover metals. The process produces alkalinity, neutralizing the AMD simultaneously. The sulfide that is produced reacts with the metal in solution and precipitates them as metal sulfides. Here, important factors for biotechnological application of SRB such as the inocula, the pH of the process, the substrates and the reactor design are discussed. Microbial communities of sulfidogenic reactors treating AMD which comprise fermentative-, acetogenic- and SRB as well as methanogenic archaea are reviewed. PMID:24444599

  9. Synthetic effect between iron oxide and sulfate mineral on the anaerobic transformation of organic substance.

    PubMed

    Chen, Tian-Hu; Wang, Jin; Zhou, Yue-Fei; Yue, Zheng-Bo; Xie, Qiao-Qin; Pan, Min

    2014-01-01

    Synthetic effect between sulfate minerals (gypsum) and iron oxide (hematite) on the anaerobic transformation of organic substance was investigated in the current study. The results showed that gypsum was completely decomposed while hematite was partially reduced. The mineral phase analysis results showed that FeS and CaCO3 was the major mineralization product. Methane generation process was inhibited and inorganic carbon contents in the precipitates were enhanced compared to the control without hematite and gypsum. The inorganic carbon content increased with the increasing of hematite dosages. Co-addition of sulfate minerals and iron oxide would have a potential application prospect in the carbon sequestration area and reduction of the greenhouse gas release. The results would also reveal the role of inorganic mineral in the global carbon cycle. PMID:24189378

  10. Sulfation of sialyl N-acetyllactosamine oligosaccharides and fetuin oligosaccharides by keratan sulfate Gal-6-sulfotransferase.

    PubMed

    Torii, T; Fukuta, M; Habuchi, O

    2000-02-01

    We have previously cloned keratan sulfate Gal-6-sulfotransferase (KSGal6ST), which transfers sulfate from 3'-phosphoadenosine 5'-phosphosulfate to position 6 of Gal residue of keratan sulfate. In this study, we examined whether KSGal6ST could transfer sulfate to sialyl N -acetyllactosamine oligosaccharides or fetuin oligo-saccharides. KSGal6ST expressed in COS-7 cells catalyzed transfer of sulfate to NeuAcalpha2-3Galbeta1-4GlcNAc (3'SLN), NeuAcalpha2-3Galbeta1-4GlcNAcbeta1-3Galbeta1-4Gl cNAc (SL1L1), NeuAcalpha2-3Galbeta1-4(6-sulfo)GlcNAcbeta1-3(6-sulfo) Galbeta1-4(6-su lfo)GlcNAc (SL2L4), and their desialylated derivatives except for Galbeta1-4GlcNAc, but not to NeuAcalpha2-3Galbeta1-4(Fucalpha1-3)GlcNAc (SLex). When the sulfated product formed from 3'SLN was degraded with neuraminidase and reduced with NaBH(4), the resulting sulfated disaccharide alditol showed the same retention time in SAX-HPLC as that of [(3)H]Gal(6SO(4))beta1-4GlcNAc-ol. KSGal6ST also catalyzed sulfation of fetuin. When the sulfated oligosaccharides released from the sulfated fetuin after sequential digestion with proteinase and neuraminidase were subjected to a reaction sequence of hydrazin-olysis, deaminative cleavage and NaBH(4)reduction, the major product was co-eluted with [(3)H]Gal(6SO(4))beta1-4anhydromannitol in SAX-HPLC. These observations show that KSGal6ST is able to sulfate position 6 of Gal residue of 3'SLN and fetuin oligosaccharides. The relative rates of the sulfation of SL2L4 was much higher than the rate of the sulfation of keratan sulfate. These results suggest that KSGal6ST may function in the sulfation of sialyl N -acetyllactosamine oligosaccharide chains attached to glycoproteins. PMID:10642612

  11. N-sulfation of heparan sulfate regulates early branching events in the developing mammary gland.

    PubMed

    Bush, Kevin T; Crawford, Brett E; Garner, Omai B; Nigam, Kabir B; Esko, Jeffrey D; Nigam, Sanjay K

    2012-12-01

    Branching morphogenesis, a fundamental process in the development of epithelial organs (e.g. breast, kidney, lung, salivary gland, prostate, pancreas), is in part dependent on sulfation of heparan sulfate proteoglycans. Proper sulfation is mediated by biosynthetic enzymes, including exostosin-2 (Ext2), N-deacetylase/N-sulfotransferases and heparan sulfate O-sulfotransferases. Recent conditional knockouts indicate that whereas primary branching is dependent on heparan sulfate, other stages are dependent upon selective addition of N-sulfate and/or 2-O sulfation (Crawford, B .E., Garner, O. B., Bishop, J. R., Zhang, D. Y., Bush, K. T., Nigam, S. K., and Esko, J. D. (2010) PLoS One 5, e10691; Garner, O .B., Bush, K. T., Nigam, S .K., Yamaguchi, Y., Xu, D., Esko, J. D., and Nigam, S. K. (2011) Dev. Biol. 355, 394-403). Here, we analyzed the effect of deleting both Ndst2 and Ndst1. Whereas deletion of Ndst1 has no major effect on primary or secondary branching, deletion of Ndst2 appears to result in a mild increase in branching. When both genes were deleted, ductal growth was variably diminished (likely due to variable Cre-recombinase activity), but an overabundance of branched structures was evident irrespective of the extent of gland growth or postnatal age. "Hyperbranching" is an unusual phenotype. The effects on N-sulfation and growth factor binding were confirmed biochemically. The results indicate that N-sulfation or a factor requiring N-sulfation regulates primary and secondary branching events in the developing mammary gland. Together with previous work, the data indicate that different stages of ductal branching and lobuloalveolar formation are regulated by distinct sets of heparan sulfate biosynthetic enzymes in an appropriate growth factor context. PMID:23060443

  12. Barium isotopes in Allende meteorite: evidence against an extinct superheavy element

    Microsoft Academic Search

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

    1983-01-01

    Carbon and chromite fractions from the Allende meteorite that contain isotopically anomalous xenon-131 to xenon-136 (carbonaceous chondrite fission or CCF xenon) at up to 5 x 10¹¹ atoms per gram show no detectable isotopic anomalies in barium-130 to barium-138. This rules out the possibility that the CCF xenon was formed by in situ fission of an extinct superheavy element. Apparently

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

    NASA Technical Reports Server (NTRS)

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

    1983-01-01

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

  14. Dynamic Release of Vitamin B2 from Floating Barium Alginate Beads for Gastric Delivery

    Microsoft Academic Search

    S. K. Bajpai; Seema Dubey

    2007-01-01

    The present study is focused on the development of floating barium alginate beads, which after oral administration, are intended to prolong the gastric residence time and increase the drug bioavailability. Out of three different barium alginate bead samples prepared using NaHCO3 as porogen, the beads prepared with 4 and 5 percent solutions of sodium alginate and with 1.5% content of

  15. Barium isotopes in allende meteorite: evidence against an extinct superheavy element.

    PubMed

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

    1983-12-01

    Carbon and chromite fractions from the Allende meteorite that contain isotopically anomalous xenon-131 to xenon-136 (carbonaceous chondrite fission or CCF xenon) at up to 5 x 10(11) atoms per gram show no detectable isotopic anomalies in barium-130 to barium-138. This rules out the possibility that the CCF xenon was formed by in situ fission of an extinct superheavy element. Apparently the CCF xenon and its carbonaceous carrier are relics from stellar nucleosynthesis. PMID:17776244

  16. Experimental investigations on barium titanate nanocomposite thin films as an opto-electronic humidity sensor

    Microsoft Academic Search

    Nidhi Verma; Satyendra Singh; B. C. Yadav

    2012-01-01

    This article reports the synthesis and characterisation of Barium titanate (BaTiO3) nanocomposite and its application as opto-electronic humidity sensor. Titanium tetrachloride and barium hydroxide were mixed in molar ratio 1?:?1 in deionised water under continuous stirring at room temperature. Later, sodium hydroxide solution was added to above solution with continuous stirring. Finally, BaTiO3 gel was obtained. The synthesised nano-composite material

  17. Highly aluminium doped barium and strontium ferrite nanoparticles prepared by citrate auto-combustion synthesis

    Microsoft Academic Search

    Neil J.. Shirtcliffe; Simon Thompson; Eoin S. O’Keefe; Steve Appleton; Carole C.. Perry

    2007-01-01

    Aluminium doped barium and strontium hexaferrite nanoparticles BaAlxFe(12?x)O19 and SrAlxFe(12?x)O19 were synthesised via a sol–gel route using citric acid to complex the ions followed by an auto-combustion reaction. This method shows promise for the synthesis of complex ferrite powders with small particle size. It was found that around half of the iron could be substituted for aluminium in the barium

  18. Ammonia fuel cell using doped barium cerate proton conducting solid electrolytes

    Microsoft Academic Search

    L. Pelletier; A. McFarlan; N. Maffei

    2005-01-01

    Proton-conducting solid electrolytes composed of gadolinium-doped barium cerate (BCG) or gadolinium and praseodymium-doped barium cerate (BCGP) were tested in an intermediate-temperature fuel cell in which hydrogen or ammonia was directly fed. At 700°C, BCG electrolytes with porous platinum electrodes showed essentially no loss in performance in pure hydrogen. Under direct ammonia at 700°C, power densities were only slightly lower compared

  19. The role of barium swallow in the management of the globus pharyngeus

    Microsoft Academic Search

    A. Alaani; S. Vengala; M. N. Johnston

    2007-01-01

    Globus pharyngeus is a common benign condition with controversial management. Patients with globus pharyngeus are usually\\u000a investigated to exclude the possibility of upper aerodiagestive malignancies. There is a great debate about the role of barium\\u000a swallow in the management of this condition. Review of 1,145 barium swallow repourts of patients presented with globus pharyngeus\\u000a between 1999 and 2004 has failed

  20. [Glucagon-based cleansing enemas prior to a double-contrast barium enema].

    PubMed

    Pietilä, J A

    1992-01-01

    The cleansing effect of large-volume enemas supported or unsupported by glucagon was studied in 20 each outpatients before a double-contrast barium enema. There was no statistically significant difference in respect of the remaining rests of faeces and the contrast medium coat. Patients suffering from intestinal spasms and anal insufficiency experience a feeling of relief by the intramuscular administration of glucagon during the preparatory enema; the quality of the double-contrast barium enema is not affected. PMID:1547292

  1. Measurement of Global Precipitation

    NASA Technical Reports Server (NTRS)

    Flaming, Gilbert Mark

    2004-01-01

    The Global Precipitation Measurement (GPM) Program is an international cooperative effort whose objectives are to (a) obtain increased understanding of rainfall processes, and (b) make frequent rainfall measurements on a global basis. The National Aeronautics and Space Administration (NASA) of the United States and the Japanese Aviation and Exploration Agency (JAXA) have entered into a cooperative agreement for the formulation and development of GPM. This agreement is a continuation of the partnership that developed the highly successful Tropical Rainfall Measuring Mission (TRMM) that was launched in November 1997; this mission continues to provide valuable scientific and meteorological information on rainfall and the associated processes. International collaboration on GPM from other space agencies has been solicited, and discussions regarding their participation are currently in progress. NASA has taken lead responsibility for the planning and formulation of GPM, Key elements of the Program to be provided by NASA include a Core satellite bus instrumented with a multi-channel microwave radiometer, a Ground Validation System and a ground-based Precipitation Processing System (PPS). JAXA will provide a Dual-frequency Precipitation Radar for installation on the Core satellite and launch services. Other United States agencies and international partners may participate in a number of ways, such as providing rainfall measurements obtained from their own national space-borne platforms, providing local rainfall measurements to support the ground validation activities, or providing hardware or launch services for GPM constellation spacecraft. This paper will present an overview of the current planning for the GPM Program, and discuss in more detail the status of the lead author's primary responsibility, development and acquisition of the GPM Microwave Imager.

  2. Dynamics of Bacterial Sulfate Reduction in a Eutrophic Lake

    PubMed Central

    Ingvorsen, K.; Zeikus, J. G.; Brock, T. D.

    1981-01-01

    Bacterial sulfate reduction in the surface sediment and the water column of Lake Mendota, Madison, Wis., was studied by using radioactive sulfate (35SO42?). High rates of sulfate reduction were observed at the sediment surface, where the sulfate pool (0.2 mM SO42?) had a turnover time of 10 to 24 h. Daily sulfate reduction rates in Lake Mendota sediment varied from 50 to 600 nmol of SO42? cm?3, depending on temperature and sampling date. Rates of sulfate reduction in the water column were 103 times lower than that for the surface sediment and, on an areal basis, accounted for less than 18% of the total sulfate reduction in the hypolimnion during summer stratification. Rates of bacterial sulfate reduction in the sediment were not sulfate limited at sulfate concentrations greater than 0.1 mM in short-term experiments. Although sulfate reduction seemed to be sulfate limited below 0.1 mM, Michaelis-Menten kinetics were not observed. The optimum temperature (36 to 37°C) for sulfate reduction in the sediment was considerably higher than in situ temperatures (1 to 13°C). The response of sulfate reduction to the addition of various electron donors metabolized by sulfate-reducing bacteria in pure culture was investigated. The degree of stimulation was in this order: H2 > n-butanol > n-propanol > ethanol > glucose. Acetate and lactate caused no stimulation. PMID:16345898

  3. ENZYMATIC BASIS FOR ASSIMILATORY AND DISSIMILATORY SULFATE REDUCTION

    PubMed Central

    Peck, H. D.

    1961-01-01

    Peck, H. D., Jr. (Oak Ridge National Laboratory, Oak Ridge, Tenn.). Enzymatic basis for assimilatory and dissimilatory sulfate reduction. J. Bacteriol. 82: 933–939. 1961.—Two pathways for the reduction of sulfate to sulfite in bacteria have been previously described. The substrate for sulfate reduction by extracts of yeast is 3?-phosphoadenosine-5?-phosphosulfate (PAPS) and, in contrast, the substrate for sulfate reduction in extracts of Desulfovibrio desulfuricans is adenosine-5?-phosphosulfate (APS). The enzymes catalyzing these reductions have been termed PAPS-reductase and APS-reductase, respectively. Since yeasts are “assimilatory sulfate reducers”, i.e., reduce only enough sulfate to satisfy nutritional requirements for sulfur, and D. desulfuricans is a “dissimilatory sulfate reducer”, i.e., utilizes sulfate as its terminal electron acceptor in anaerobic respiration, the pathway of sulfate reduction was determined in 25 microorganisms to ascertain whether there is a correlation between the pathway of sulfate reduction and the physiological role of sulfate in the metabolism of bacteria. Assimilatory sulfate reducers reduced sulfate in the form of PAPS, and, with one exception, APS-reductase was found only in dissimilatory sulfate reducers. APS-reductase was also found in the Thiobacilli in high specific activity and is involved in the oxidation of reduced sulfur compounds to sulfate. PMID:14484818

  4. Basement membrane heparan sulfate proteoglycan is the main proteoglycan synthesized by glomerular epithelial cells in culture.

    PubMed Central

    Stow, J. L.; Soroka, C. J.; MacKay, K.; Striker, L.; Striker, G.; Farquhar, M. G.

    1989-01-01

    The production and distribution of basement membrane-type heparan sulfate proteoglycans (BM HSPG) were investigated in a mouse glomerular epithelial cell line. Confluent cell monolayers were radiolabeled with [35S]sulfate or [35S]cysteine. Proteoglycans were isolated from the medium and cell layers by ion exchange chromatography and their nature determined by enzyme digestion (chondroitinase ABC) or degradative treatment (nitrous acid). It was found that more than 80% of the proteoglycans in both the cell layer and medium were heparan sulfate proteoglycans (HSPG) based on their susceptibility to nitrous acid degradation. More than half of the HSPG in the cell layer could be precipitated with an antiserum that specifically recognizes BM HSPG; only 10% of those released into the medium were precipitated with this antiserum. When immunoprecipitates of [35S] sulfate-labeled proteoglycans were analyzed by SDS-PAGE, the mature proteoglycans ran as a broad band at the top of the gel. When immunoprecipitates of [35S]cysteine-labeled proteoglycans were similarly analyzed, a 250 kd precursor core protein band was seen in addition to the mature proteoglycan. When BM HSPG were localized by immunofluorescence and immunoelectron microscopy (immunoperoxidase), they were found intracellularly in biosynthetic compartments (ER and Golgi cisternae) and extracellularly in deposits of basement membrane-like matrix located beneath and between the cells. These results indicate that l) BM HSPG are the predominant type of proteoglycans made by glomerular epithelial cells in culture; 2) these HSPG are assembled into a loosely organized matrix that is deposited beneath and between the cells; and 3) this cell type produces a higher proportion of BM HSPG than other cultured epithelial cells studied previously. Images Figure 6 Figure 1 Figure 5 PMID:2529772

  5. The Global Precipitation Climatology Project (GPCP) Combined Precipitation Dataset

    NASA Technical Reports Server (NTRS)

    Huffman, George J.; Adler, Robert F.; Arkin, Philip; Chang, Alfred; Ferraro, Ralph; Gruber, Arnold; Janowiak, John; McNab, Alan; Rudolf, Bruno; Schneider, Udo

    1997-01-01

    The Global Precipitation Climatology Project (GPCP) has released the GPCP Version 1 Combined Precipitation Data Set, a global, monthly precipitation dataset covering the period July 1987 through December 1995. The primary product in the dataset is a merged analysis incorporating precipitation estimates from low-orbit-satellite microwave data, geosynchronous-orbit -satellite infrared data, and rain gauge observations. The dataset also contains the individual input fields, a combination of the microwave and infrared satellite estimates, and error estimates for each field. The data are provided on 2.5 deg x 2.5 deg latitude-longitude global grids. Preliminary analyses show general agreement with prior studies of global precipitation and extends prior studies of El Nino-Southern Oscillation precipitation patterns. At the regional scale there are systematic differences with standard climatologies.

  6. Plasma deposition of thin layers containing titanium and barium with the use of DBD

    NASA Astrophysics Data System (ADS)

    Majdak, Ma?gorzata; Opali?ska, Teresa; Wn?k, Bart?omiej; Konarski, Piotr

    2013-02-01

    Two different methods of deposition of thin layers containing titanium and barium with the use of dielectric barrier discharge were investigated. The first was carried out in two stages. The first stage consisted in transferring compounds containing titanium and barium from the vapor of the organic precursor to the copper substrate, while the second stage involved the etching of the organic layer in oxygen. The second method consisted in transferring titanium and barium to the copper substrate from the ceramic plate made of barium titanate, which was one of the electrodes during the plasma process. The results of analysis obtained by SIMS showed directly that both methods gave a positive result in the deposition of the thin layers containing a certain amount of titanium and barium on the surface of the copper plate. However, more effective method was that involving the properties of reaction with the metallorganic precursor. FTIR study of the layers prepared from the organic precursor indirectly showed that layers deposited on the copper plate contained compounds of barium and titanium. FTIR study also revealed that during the process of etching in oxygen, the organic layer was decreased, but it was not completely removed. Contribution to the Topical Issue "13th International Symposium on High Pressure Low Temperature Plasma Chemistry (Hakone XIII)", Edited by Nicolas Gherardi, Henryca Danuta Stryczewska and Yvan Ségui.

  7. Spatial Distribution of Sulfate and the Formation of Ettringite in Lime-Amended Soils of Central Texas

    NASA Astrophysics Data System (ADS)

    Kuo, L.; Markley, C. T.; Herbert, B. E.; Little, D. N.

    2004-12-01

    During road construction, the use of calcium-based stabilizers, such as calcium oxide (lime), in sulfate-bearing clay soils has historically lead to distress and heave due to the formation of ettringite and possibly thaumasite. Ettringite (Ca6(Al(OH)6)2(SO4)3*26H2O) is a hydrous calcium alumino-sulfate mineral that precipitates in environments with high pH and high sulfate activity. Field surveys of soil conductivity quantified using electromagnetics (EM31), geochemical characterization of soils, geochemical modeling of ettringite precipitation in lime-amended soils, and landscape characterization using existing geospatial databases were coupled to prediction the potential for ettringite formation along the SH 130 corridor, a new toll road being constructed in central Texas. Electromagnetic surveys of soil conductivities were conducted at two sites near HWY 290 and HWY 79, in the SH 130 corridor. Soil conductivities at the two sites were correlated extractable SO42- and other soil properties (extractable Al, Ca, and Mg) quantified by water extracts at two pHs (pH 8-9 and 12). At the HWY 290 site, the soil conductivity ranged from 111 to 184 ms/m, while the conductivity ranged from 34-48 ms/m at the HWY 79 site. The concentration of extractable SO42- in HWY 290 and HWY 79 sites are up to 7269 mg/kg and 406 mg/kg, respectively. Soils at these sites are dominated by smectitic clay with relatively high amounts of carbonate. Information from STATSGO, the USDA soil database, and the comparisons between the results of the field surveys and laboratory soil analyses show that variations in sulfate levels at the two sites are strongly influenced by topography. The HWY 79 site is fairly level and there are only very weak trends in the sulfate composition of the soils. The HWY 290 site, on the other hand, is fairly hilly, with a dry stream channel, whose soil and sediments exhibited very high sulfate concentrations. The strong topographic slope influences hydrologic flow, including both surface runoff and subsurface flow, which transports sulfate down slope. In addition, evapotranspiration during the dry season would also help accumulate sulfate in low-lying areas due to solute transport from near-surface ground waters. This study demonstrates that electromagnetics can be used for in-situ, field-scale survey of sulfates. Coupled with the application of geochemical speciation models, we assess the potential of ettringite formation in the SH 130 corridor.

  8. Recent advances in the structural biology of chondroitin sulfate and dermatan sulfate

    Microsoft Academic Search

    Kazuyuki Sugahara; Tadahisa Mikami; Toru Uyama; Souhei Mizuguchi; Kazuya Nomura; Hiroshi Kitagawa

    2003-01-01

    Recent glycobiology studies have suggested fundamental biological functions for chondroitin, chondroitin sulfate and dermatan sulfate, which are widely distributed as glycosaminoglycan sidechains of proteoglycans in the extracellular matrix and at cell surfaces. They have been implicated in the signaling functions of various heparin-binding growth factors and chemokines, and play critical roles in the development of the central nervous system. They

  9. The effect of sulfate on aluminum concentrations in natural waters: some stability relations in the system Al2O3-SO3-H2O at 298 K

    USGS Publications Warehouse

    Nordstrom, D.K.

    1982-01-01

    While gibbsite and kaolinite solubilities usually regulate aluminum concentrations in natural waters, the presence of sulfate can dramatically alter these solubilities under acidic conditions, where other, less soluble minerals can control the aqueous geochemistry of aluminum. The likely candidates include alunogen, Al2(SO4)3 ?? 17H2O, alunite, KAl3(SO4)2(OH)6, jurbanite, Al(SO4)(OH) ?? 5H2O, and basaluminite, Al4(SO4)(OH)10 ?? 5H2O. An examination of literature values shows that the log Ksp = -85.4 for alunite and log Ksp = -117.7 for basaluminite. In this report the log Ksp = -7.0 is estimated for alunogen and log Ksp = -17.8 is estimated for jurbanite. The solubility and stability relations among these four minerals and gibbsite are plotted as a function of pH and sulfate activity at 298 K. Alunogen is stable only at pH values too low for any natural waters (<0) and probably only forms as efflorescences from capillary films. Jurbanite is stable from pH < 0 up to the range of 3-5 depending on sulfate activity. Alunite is stable at higher pH values than jurbanite, up to 4-7 depending on sulfate activity. Above these pH limits gibbsite is the most stable phase. Basaluminite, although kinetically favored to precipitate, is metastable for all values of pH and sulfate activity. These equilibrium calculations predict that both sulfate and aluminum can be immobilized in acid waters by the precipitation of aluminum hydroxysulfate minerals. Considerable evidence supports the conclusion that the formation of insoluble aluminum hydroxy-sulfate minerals may be the cause of sulfate retention in soils and sediments, as suggested by Adams and Rawajfih (1977), instead of adsorption. ?? 1982.

  10. Computer simulation of deep sulfate reduction in sediments of the Amazon Fan

    NASA Astrophysics Data System (ADS)

    Adler, M.; Hensen, C.; Kasten, S.; Schulz, H. D.

    Pore water concentration profiles of sediments at a site on the Amazon Fan were investigated and simulated with the numerical model CoTReM (column transport and reaction model) to reveal the biogeochemical processes involved. The pore water profiles for gravity core GeoB 4417-7 showed a distinct sulfate-methane transition zone in which deep sulfate reduction occurs. Only a small sulfide peak could be observed at the reaction zone. Due to high amounts of iron minerals, the produced sulfide is instantaneously precipitated in form of iron sulfides. We present a simulation which starts from a steady state system with respect to pore water profiles for methane and sulfate. Furthermore, sulfide, iron, pH, pE, calcium and total inorganic carbon (TIC) were included in the simulation. The program calculated mineral equilibria to mackinawite, iron sulfides (more stable than mackinawite), iron hydroxides and calcite via saturation indices (SI) by a module incorporating the program PHREEQC (Parkhurst 1995). The measured sulfide and iron profiles are obtained in the simulation output by using a constant SI (=0) for mackinawite and calcite, while a depth dependent SI distribution is applied for the PHREEQC phases ``Pyrite'' and ``Fe(OH)3(a)'', representing a composition and the kinetics of different iron sulfides and iron hydroxides. These SI distributions control the results of sulfide and iron pore water profiles, especially conserving the sulfide profile at the reaction zone during the simulation. The results suggest that phases of iron hydroxides are dissolved, mackinawite is precipitated within, and other iron sulfides are precipitated below the reaction zone. The chemical reactivity of iron hydroxides corresponds to the rate of sulfide production. The system H2O-CO2-CaCO3 is generally successfully maintained during the simulation. Deviations to the measured pH profile suggest that further processes are active which are not included in the simulation yet.

  11. Enzymatic iron and uranium reduction by sulfate-reducing bacteria

    USGS Publications Warehouse

    Lovley, D.R.; Roden, E.E.; Phillips, E.J.P.; Woodward, J.C.

    1993-01-01

    The potential for sulfate-reducing bacteria (SRB) to enzymatically reduce Fe(III) and U(VI) was investigated. Five species of Desulfovibrio as well as Desulfobacterium autotrophicum and Desulfobulbus propionicus reduced Fe(III) chelated with nitrilotriacetic acid as well as insoluble Fe(III) oxide. Fe(III) oxide reduction resulted in the accumulation of magnetite and siderite. Desulfobacter postgatei reduced the chelated Fe(III) but not Fe(III) oxide. Desulfobacter curvatus, Desulfomonile tiedjei, and Desulfotomaculum acetoxidans did not reduce Fe(III). Only Desulfovibrio species reduced U(VI). U(VI) reduction resulted in the precipitation of uraninite. None of the SRB that reduced Fe(III) or U(VI) appeared to conserve enough energy to support growth from this reaction. However, Desulfovibrio desulfuricans metabolized H2 down to lower concentrations with Fe(III) or U(VI) as the electron acceptor than with sulfate, suggesting that these metals may be preferred electron acceptors at the low H2 concentrations present in most marine sediments. Molybdate did not inhibit Fe(III) reduction by D. desulfuricans. This indicates that the inability of molybdate to inhibit Fe(III) reduction in marine sediments does not rule out the possibility that SRB are important catalysts for Fe(III) reduction. The results demonstrate that although SRB were previously considered to reduce Fe(III) and U(VI) indirectly through the production of sulfide, they may also directly reduce Fe(III) and U(VI) through enzymatic mechanisms. These findings, as well as our recent discovery that the So-reducing microorganism Desulfuromonas acetoxidans can reduce Fe(III), demonstrate that there are close links between the microbial sulfur, iron, and uranium cycles in anaerobic marine sediments. ?? 1993.

  12. Sulfur pollution from coal combustion: effect of the mineral components of coal on the thermal stabilities of sulfated ash and calcium sulfate

    Microsoft Academic Search

    Daniel C. Baker; Amir Attar

    1981-01-01

    The rate and mechanisms of the decomposition of sulfated coal ashes, calcium sulfate, and calcium sulfate mixed with coal and with minerals were investigated. Sulfated ashes were less stable than pure calcium sulfate\\/ however, their rate of decomposition was less sensitive to the addition of minerals. Release of sulfur oxides from calcium sulfate mixed with coal stopped after a very

  13. Theoretical determination of O and S isotope fractionations between gypsum and aqueous sulfate

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Bao, H.

    2009-12-01

    Some non-labile oxyanions, such as sulfate (SO42-) or nitrate (NO3-), do not exchange O atoms readily with O in water at ambient temperatures. They often behave like a single atom during mineral precipitation, dissolution, adsorption, and even microbial transport. Considering the many different isotopologues these oxyanions usually possess, for example, SO42- has 32-16-16-16-16, 34-16-16-16-16, 32-18-16-16-16, 34-18-16-16-16, …, etc., the behaviour of isotope fractionation for different elements in the oxyanions (e.g., O and S) may lead to certain degrees of coupling during different physical, chemical, and biological processes. Here, we use an aqueous sulfate - solid gypsum (CaSO4-2H2O) system to illustrate a first-principle approach to calculating the isotope fractionation factors and their coupling for O and S in sulfate during gypsum precipitation. Using Urey model or Bigeleisen-Mayer equation in combination with quantum chemistry calculations (at B3LYP/6-311+G(2df,p) level), we have calculated equilibrium isotope fractionation factors ?18 and ?34 for tens of isotopologues of SO42-. We use a time-consuming yet explicit solvent model (i.e. “water-droplet”) to precisely evaluate solvation effects for aqueous sulfate species. A large and partially fixed cluster model is used for simulating gypsum mineral surface. Our results show that the equilibrium fractionations at 25°C between solid gypsum and aqueous sulfate are ~ 2.5 and 1.6 ‰ for the ??18O and ??34S, respectively. Without considering ion-pair effect on sulfate anion in solution, however, the corresponding ??18O and ??34S become ~ 4.4 and 2.8 ‰, respectively. Our work presents a new approach to predicting isotope fractionation behaviour for no-labile species at equilibrium and lays the ground for evaluating kinetic effects. The results also shed lights on the mechanism and model for gypsum crystal growth at molecular level.

  14. Precipitation extremes under climate change

    E-print Network

    O'Gorman, Paul A

    2015-01-01

    The response of precipitation extremes to climate change is considered using results from theory, modeling, and observations, with a focus on the physical factors that control the response. Observations and simulations with climate models show that precipitation extremes intensify in response to a warming climate. However, the sensitivity of precipitation extremes to warming remains uncertain when convection is important, and it may be higher in the tropics than the extratropics. Several physical contributions govern the response of precipitation extremes. The thermodynamic contribution is robust and well understood, but theoretical understanding of the microphysical and dynamical contributions is still being developed. Orographic precipitation extremes and snowfall extremes respond differently from other precipitation extremes and require particular attention. Outstanding research challenges include the influence of mesoscale convective organization, the dependence on the duration considered, and the need to...

  15. Acetate production from oil under sulfate-reducing conditions in bioreactors injected with sulfate and nitrate.

    PubMed

    Callbeck, Cameron M; Agrawal, Akhil; Voordouw, Gerrit

    2013-08-01

    Oil production by water injection can cause souring in which sulfate in the injection water is reduced to sulfide by resident sulfate-reducing bacteria (SRB). Sulfate (2 mM) in medium injected at a rate of 1 pore volume per day into upflow bioreactors containing residual heavy oil from the Medicine Hat Glauconitic C field was nearly completely reduced to sulfide, and this was associated with the generation of 3 to 4 mM acetate. Inclusion of 4 mM nitrate inhibited souring for 60 days, after which complete sulfate reduction and associated acetate production were once again observed. Sulfate reduction was permanently inhibited when 100 mM nitrate was injected by the nitrite formed under these conditions. Pulsed injection of 4 or 100 mM nitrate inhibited sulfate reduction temporarily. Sulfate reduction resumed once nitrate injection was stopped and was associated with the production of acetate in all cases. The stoichiometry of acetate formation (3 to 4 mM formed per 2 mM sulfate reduced) is consistent with a mechanism in which oil alkanes and water are metabolized to acetate and hydrogen by fermentative and syntrophic bacteria (K. Zengler et al., Nature 401:266-269, 1999), with the hydrogen being used by SRB to reduce sulfate to sulfide. In support of this model, microbial community analyses by pyrosequencing indicated SRB of the genus Desulfovibrio, which use hydrogen but not acetate as an electron donor for sulfate reduction, to be a major community component. The model explains the high concentrations of acetate that are sometimes found in waters produced from water-injected oil fields. PMID:23770914

  16. Dissolved sulfide-catalyzed precipitation of disordered dolomite: Implications for the formation mechanism of sedimentary dolomite

    NASA Astrophysics Data System (ADS)

    Zhang, Fangfu; Xu, Huifang; Konishi, Hiromi; Kemp, Joshua M.; Roden, Eric E.; Shen, Zhizhang

    2012-11-01

    Dolomite is a common mineral in the rock record. However, the rarity of modern dolomite and the notorious difficulty in synthesizing dolomite abiotically under normal Earth-surface conditions result in the long-standing “dolomite problem” in sedimentary geology. Some modern dolomites are associated with sediments where microbial sulfate reduction is active; however, the role of sulfate-reducing bacteria in dolomite formation is still under debate. In this study, we tested the effect of dissolved sulfide on the precipitation of Ca-Mg carbonates, which has been never explored before although dissolved sulfide is one of the major products of microbial sulfate reduction. Our results demonstrated that dissolved sulfide with a concentration of as low as several millimoles can enhance the Mg2+ incorporation into the calcitic structure, and promote the crystallization of high magnesian calcite and disordered dolomite. We also conducted seeded precipitation in experimental solutions containing dissolved sulfide, which showed that calcite seeds can inhibit the precipitation of aragonite and monohydrocalcite (CaCO3·H2O), and induce more Mg2+ incorporation. We propose that accumulated dissolved sulfide in pore waters in organic-rich sediments may trigger the precipitation of disordered dolomite which can be considered as a precursor of some sedimentary dolomite. Our adsorption experiments revealed a strong adsorption of dissolved sulfide onto calcite faces. We suggest that adsorbed dissolved sulfide can lower the energy barrier to the dehydration of Mg2+-water complexes on the growing carbonate surfaces. This study sheds new light on understanding the role of sulfate-reducing bacteria in dolomite formation and the formation mechanism of sedimentary dolomite.

  17. Theoretical determination of O and S isotope fractionations between gypsum and aqueous sulfate

    Microsoft Academic Search

    Y. Liu; H. Bao

    2009-01-01

    Some non-labile oxyanions, such as sulfate (SO42-) or nitrate (NO3-), do not exchange O atoms readily with O in water at ambient temperatures. They often behave like a single atom during mineral precipitation, dissolution, adsorption, and even microbial transport. Considering the many different isotopologues these oxyanions usually possess, for example, SO42- has 32-16-16-16-16, 34-16-16-16-16, 32-18-16-16-16, 34-18-16-16-16, ..., etc., the behaviour

  18. Immunobiological behaviour of rabbit precipitating and non-precipitating (co-precipitating) antibodies.

    PubMed

    Margni, R A; Perdigón, G; Abatángelo, C; Gentile, T; Binaghi, R A

    1980-11-01

    Complement fixing capacity, antibody-dependent cell cytotoxicity and in vivo opsonic function of rabbit anti-DNP precipitating and co-precipitating antibodies were analysed. Precipitating antibody activated the complement system, but co-precipitating antibody did not. Both antibody preparations behaved similarly in antibody-dependent cytotoxicity reactions. When chicken erythrocytes were employed as target cells, both antibodies were inactive with homologous (rabbit) lymphocytes as effector cells but were active with heterologous lymphoid effector cells (human, guinea-pig). Clearance of antigen from the blood of mice was accelerated following injection of an optimal dose of precipitating antibody but co-precipitating antibody was ineffective even at different doses. Competition between precipitating and co-precipitating antibodies in complement fixation and antigen elimination following interaction with antigen successively or at the same time was investigated. In these tests, both antibodies competed with antigen by mass but not by affinity. The possibility exists that co-precipitating antibody has one high and one low affinity binding site and thus acts as an univalent blocking antibody and is therefore not able to form active complexes with antigen. The possible role of co-precipitating antibody in some humoral and cellular immune mechanisms is discussed. PMID:7461708

  19. Artifactual Sulfation of Silver-stained Proteins

    PubMed Central

    Gharib, Marlene; Marcantonio, Maria; Lehmann, Sylvia G.; Courcelles, Mathieu; Meloche, Sylvain; Verreault, Alain; Thibault, Pierre

    2009-01-01

    Sulfation and phosphorylation are post-translational modifications imparting an isobaric 80-Da addition on the side chain of serine, threonine, or tyrosine residues. These two post-translational modifications are often difficult to distinguish because of their similar MS fragmentation patterns. Targeted MS identification of these modifications in specific proteins commonly relies on their prior separation using gel electrophoresis and silver staining. In the present investigation, we report a potential pitfall in the interpretation of these modifications from silver-stained gels due to artifactual sulfation of serine, threonine, and tyrosine residues by sodium thiosulfate, a commonly used reagent that catalyzes the formation of metallic silver deposits onto proteins. Detailed MS analyses of gel-separated protein standards and Escherichia coli cell extracts indicated that several serine, threonine, and tyrosine residues were sulfated using silver staining protocols but not following Coomassie Blue staining. Sodium thiosulfate was identified as the reagent leading to this unexpected side reaction, and the degree of sulfation was correlated with increasing concentrations of thiosulfate up to 0.02%, which is typically used for silver staining. The significance of this artifact is discussed in the broader context of sulfation and phosphorylation site identification from in vivo and in vitro experiments. PMID:18936056

  20. [Study on adsorption behavior of nanosized barium-strontium titanate powder for lead ion in water using FAAS].

    PubMed

    Zhang, Dong; Su, Hui-Dong; Gao, Hong

    2008-01-01

    Nanosized barium-stroutium titanate (BST) powder, a double salt sorbent, was prepared from BaCl2, SrCl2 and TiCl4 by using oxalate co-precipitate method, and characterized by using transmission electron microscope (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectrophotometer (FTIR). By means of determination with flame atomic absorption spectrometry (FAAS), the adsorption characteristic of lead on the BST powder w as investigated. The results showed that theforms of the BST powders are clubbed, highly pure perovskite, and the average particle diameter is 36 nm. Lead can be adsorbed strongly on nanosized BST. The adsorption capacity of BST nanoparticle towards lead was found to be 13 mg x g(-1) when the pH is 6.0, and 0.5 mol x L(-1) HNO3 is sufficient for complete elution. A new method for the determination of trace lead based on BST nanoparticle separation/preconcentration and FAAS determination was proposed. The detection limit of this method for lead ion is 11 microg x L(-1), and the relative standard deviation is 2.6%. The method has been applied to the determination of trace lead in water samples with satisfactory results. PMID:18422157

  1. Impacts of Stratospheric Sulfate Geoengineering on Chinese Agricultural Production

    NASA Astrophysics Data System (ADS)

    Xia, L.; Robock, A.

    2012-12-01

    Possible food supply change is one of the most important concerns in the discussion of stratospheric sulfate geoengineering. In China, the high population density and strong summer monsoon influence on agriculture make this region sensitive to climate changes, such as reductions of precipitation, temperature, and solar radiation spurred by stratospheric sulfate injection. We used results from the Geoengineering Model Intercomparison Project G2 scenario to force the Decision Support System for Agrotechnology Transfer (DSSAT) crop model to predict crop yield changes from rice, maize, and winter wheat. We first evaluated the DSSAT model by forcing it with daily observed weather data and management practices for the period 1978-2008 for all the provinces in China, and compared the results to observations of the yields of the three major crops in China. We then created two 50-year sets of climate anomalies using the results from eight climate models, for 1%/year increase of CO2 and for G2 (1%/year increase of CO2 balanced by insolation reduction), and compared the resulting agricultural responses. Considering that geoengineering could happen in the future, we used two geoengineering starting years, 2020 and 2060. For 2020, we increased the mean temperature by 1°C and started the CO2 concentration at 410 ppm. For 2060, we increased temperature by 2°C and started the CO2 concentration at 550 ppm. Without changing agriculture technology, we find that compared to the control run, geoengineering with the G2 scenario starting in 2020 or 2060 would both moderately increase rice and winter wheat production due to the CO2 fertilization effect, but the increasing rates are different. However, as a C4 crop, without a significant CO2 fertilization effect, maize production would decrease slightly because of regional drought. Compared to the reference run, the three crops all have less heat stress in southern China and their yields increase, but in northern China cooler temperatures cause yields to decrease, especially for winter wheat. Therefore after deploying geoengineering (G2), there are positive effects from temperature reduction, but regions with precipitation reduction may be harmful for agriculture activity. In addition, the starting year of geoengineering would affect its impacts on agriculture.

  2. Quaternary liquid/liquid equilibria of sodium sulfate, sodium sulfite and water with two solvents: Acetone and 2-propanol

    SciTech Connect

    Schiozer, A.L.

    1994-03-01

    Aqueous solutions of sodium sulfate and sodium sulfite are produced from sodium carbonate in flue-gas scrubbers; recovery of these salts often requires multi-effect evaporators; however, a new energy-efficient unit operation called extractive crystallization has been shown to have reduced energy costs. In this process, an organic solvent is added to the aqueous salt solution to precipitate salt. Acetone is a suitable solvent for this process, better than 2-propanol. Liquid/liquid/solid equilibria for ternary systems containing a salt, water, and an organic solvent were measured. Systems investigated were sodium sulfite/water/acetone and sodium sulfite/water/2-propanol. Experiments were conducted at salt saturation covering a temperature range between the lower consolute temperature and 48.6{degrees}C. In the attempt to improve the extractive crystallization process for recovery of sodium sulfate from flue-gas scrubbers, attention was given to a feed containing a mixture of sodium sulfite and sodium sulfate. Liquid-liquid equilibria for quaternary systems containing two salts, water, and an organic solvent were experimentally determined at 35{degrees}C. The systems investigated were sodium sulfate/sodium sulfite/water/acetone and sodium sulfate/sodium sulfite/water/2propanol. The systems were studied at three salt ratios. For each salt ratio, experiments were conducted starting at saturation, water was then added until the one-phase region was reached. Mixtures of the two salts proved to have a small disadvantage relative to the 100 % sulfate feed process. Therefore, a sulfate-based extractive crystallization process is recommended.

  3. Method of increasing the sulfation capacity of alkaline earth sorbents

    DOEpatents

    Shearer, J.A.; Turner, C.B.; Johnson, I.

    1980-03-13

    A system and method for increasing the sulfation capacity of alkaline earth carbonates to scrub sulfur dioxide produced during the fluidized bed combustion of coal in which partially sulfated alkaline earth carbonates are hydrated in a fluidized bed to crack the sulfate coating and convert the alkaline earth oxide to the hydroxide. Subsequent dehydration of the sulfate-hydroxide to a sulfate-oxide particle produces particles having larger pore size, increased porosity, decreased grain size and additional sulfation capacity. A continuous process is disclosed.

  4. Method of increasing the sulfation capacity of alkaline earth sorbents

    DOEpatents

    Shearer, John A. (Chicago, IL); Turner, Clarence B. (Shorewood, IL); Johnson, Irving (Clarendon Hills, IL)

    1982-01-01

    A system and method for increasing the sulfation capacity of alkaline earth carbonates to scrub sulfur dioxide produced during the fluidized bed combustion of coal in which partially sulfated alkaline earth carbonates are hydrated in a fluidized bed to crack the sulfate coating and convert the alkaline earth oxide to the hydroxide. Subsequent dehydration of the sulfate-hydroxide to a sulfate-oxide particle produces particles having larger pore size, increased porosity, decreased grain size and additional sulfation capacity. A continuous process is disclosed.

  5. Controls on the precipitation of barite (BaSO 4) crystals in calcite travertine at Twitya Spring, a warm sulphur spring in Canada's Northwest Territories

    NASA Astrophysics Data System (ADS)

    Bonny, Sandy M.; Jones, Brian

    2008-01-01

    Twitya Spring discharges warm (24 °C), anoxic, sulphide-, calcium- (65 ppm) and barium- (? 0.78 ppm) rich spring water to a steep flow path that is inhabited by streamer and mat-forming microbes ( Thiothrix, Beggiatoa, Oscillatoria, Spirulina, diatoms, rod shaped bacteria). Oxidation and CO 2 degassing drive precipitation of elemental sulphur, barite, opaline silica, and calcite. A mound of travertine at the base of the flow path, dominantly composed of bedded barium-enriched crystallographic and noncrystallographic dendritic calcite crystals and calcite cements, hosts three types of barite crystals: type 1 (T1) intergrown tabular crystals that formed in solution, type 2 (T2) tabular and rhombic crystals that nucleated on calcite, and type 3 (T3) subhedral and anhedral microcrystals that nucleated on microbial cell surfaces and in microbial extracellular polymeric substances. The formation and distribution of T1, T2, and T3 barite in the Twitya Spring flow path are controlled by physiochemical gradients, calcite precipitation rates, and adsorption of barium to microbial biomass, all of which vary seasonally and episodically at Twitya Spring. The complex physiochemical and biological controls on barite formation at Twitya Spring both suggest that the classification of biogenic or inorganic sedimentary barite on the basis of crystal size and morphology may be oversimplified. There is also the potential that primary and authigenic barite crystals hosted in carbonates may yield information about the microbial ecology and ambient physiochemistry of their depositional environments.

  6. Raman microscopy study of basic aluminum sulfate

    Microsoft Academic Search

    J. T. Kloprogge; R. L. Frost

    1999-01-01

    The tridecameric aluminum polymer [AlO4Al12(OH)24(H2O)12]7+ was prepared by forced hydrolysis of Al3+ up to an OH\\/Al molar ratio of 2.2. Upon addition of sulfate the tridecamer crystallised as the monoclinic basic aluminum sulfate Na0.1[AlO4Al12(OH)12(H2O)12](SO4)3.55. These crystals have been studied using FT-Raman microscopy and compared to the basic aluminum nitrate, Na2SO4·xH2O and Al2(SO4)3·xH2O. The Raman spectrum of basic aluminum sulfate is

  7. Integrated hydrogeological and geochemical processes in swelling clay-sulfate rocks

    NASA Astrophysics Data System (ADS)

    Schweizer, Daniel; Butscher, Christoph; Blum, Philipp

    2015-04-01

    The swelling of clay-sulfate rocks is a well-known problem in tunnel engineering where it poses a severe threat to important infrastructure. However, recently it was also encountered in an entirely different setting: The inaccurate implementation of geothermal installations in the town Staufen, Germany, led to water inflow into clay-sulfate rocks, resulting in heavy swelling. The swelling caused uplift rates of the ground surface exceeding 1 cm month-1, and severely damaged over 250 houses. The underlying processes of clay-sulfate rock swelling are complex and not yet sufficiently understood. In particular, hydraulic and geochemical processes in the zone of swelling are difficult to assess and the additional impact of constructional measures, such as borehole drilling, remains mostly unknown. The transformation of anhydrite into gypsum as a result of water influx is considered to be the main mechanism contributing to the swelling process, leading to an increase in volume of up to 60 %. This transformation process is decoupled: Anhydrite is dissolved and the pore-water concentration of sulfate increases; the dissolved sulfate may be transported with groundwater flow and finally precipitates as gypsum. Hence, groundwater flow and geochemistry of the pore-water play an essential role in the swelling processes. In fact, the swelling of clay-sulfate rocks is likely initiated by a change in geochemistry brought about by a change in hydraulic conditions. Thus, the main objective of this project is to quantify groundwater flux and geochemical reactions within swelling zones influenced by engineering activities, such as geothermal drillings. Additionally, reaction rates of anhydrite dissolution and gypsum precipitation at the field scale are to be compared with reaction rates determined in laboratory experiments. This study investigates the significance of (1) the local geological setting, (2) hydrology and geochemistry of the swelling zone and (3) their modification upon human activities (drillings), as well as (4) the reaction kinetics of the anhydrite-gypsum-water system at the field scale. It incorporates 3D geological modelling, reactive transport modelling and model validation, with a focus on the reactive transport model. The models are based on the case study of Staufen, which provides an excellent data set for model development and comparison of the model results to the actual observed swelling processes in the field. Forward modelling with validation via iterative calibration is chosen as a methodological approach. The validated models represent the geological, hydrological and geochemical conditions which cause the swelling of the clay-sulfate rocks. They also quantify the reaction kinetics, characterizing the anhydrite dissolution and gypsum precipitation during the swelling process under field conditions. In this contribution, the extensive datasets from the test site of town Staufen and their relevance for the individual model development steps are presented. They comprise geological, geophysical, hydrological, geochemical, geomechanical and geodetic information providing an excellent data basis. Furthermore, a conceptual overview of the methodology for the geological and reactive transport model, as well as model validation using the presented data, is outlined. The expected results of the study will lead to a better understanding of the hydrological and geological processes that trigger the swelling of clay-sulfate rocks.

  8. Color, organic matter and sulfate removal from textile effluents by anaerobic and aerobic processes.

    PubMed

    Amaral, F M; Kato, M T; Florêncio, L; Gavazza, S

    2014-07-01

    An upflow anaerobic sludge blanket (UASB)-submerged aerated biofilter (SAB) system was evaluated to remove color and chemical oxygen demand (COD) from real textile effluent. The system was operated for 335 days in three phases (P-1, P-2, P-3) with total hydraulic retention time varying from 21 h to 14 h. The results showed that high sulfate levels (>300 mg SO4(2-)/L) impaired the dye reduction. The best color removal efficiencies of 30% and 96% for the UASB and the reactor system, respectively, were obtained in P-1; the SAB higher efficiency was associated with adsorption. The best COD removal efficiency of 71% for the reactor system was obtained in P-2. Precipitation of some material composed mostly of sulfur (98%) and some metals occurred in the UASB. However, the precipitated sulfur was again oxidized in the SAB. The system also showed an effective toxicity reduction in tests (Daphnia magna) with the treated effluent. PMID:24813565

  9. Measurement of chemical leaching potential of sulfate from landfill disposed sulfate containing wastes.

    PubMed

    Sun, Wenjie; Barlaz, Morton A

    2015-02-01

    A number of sulfate-containing wastes are disposed in municipal solid wastes (MSW) landfills including residues from coal, wood, and MSW combustion, and construction and demolition (C&D) waste. Under anaerobic conditions that dominate landfills, the sulfate can be reduced to hydrogen sulfide which is problematic for several reasons including its low odor threshold, toxicity, and corrosive nature. The overall objective of this study was to evaluate existing protocols for the quantification of total leachable sulfate from solid samples and to compare their effectiveness and efficiency with a new protocol described in this study. Methods compared include two existing acid extraction protocols commonly used in the U.S., a pH neutral protocol that requires multiple changes of the leaching solution, and a new acid extraction method. The new acid extraction method was shown to be simple and effective to measure the leaching potential of sulfate from a range of landfill disposed sulfate-containing wastes. However, the acid extraction methods do not distinguish between sulfate and other forms of sulfur and are thus most useful when sulfate is the only form of sulfur present. PMID:25499684

  10. EVALUATION OF SULFATE-REDUCING BACTERIA TO PRECIPITATE MERCURY FROM CONTAMINATED GROUNDWATER

    EPA Science Inventory

    Several regions in the Republic of Kazakhstan are contaminated with mercury as a result of releases from industrial plants. Operations at an old chemical plant, "Khimprom", which produced chlorine and alkali in the 1970s - 1990s, resulted in significant pollution of groundwater ...

  11. On the evaporation of ammonium sulfate solution

    SciTech Connect

    Drisdell, Walter S.; Saykally, Richard J.; Cohen, Ronald C.

    2009-07-16

    Aqueous evaporation and condensation kinetics are poorly understood, and uncertainties in their rates affect predictions of cloud behavior and therefore climate. We measured the cooling rate of 3 M ammonium sulfate droplets undergoing free evaporation via Raman thermometry. Analysis of the measurements yields a value of 0.58 {+-} 0.05 for the evaporation coefficient, identical to that previously determined for pure water. These results imply that subsaturated aqueous ammonium sulfate, which is the most abundant inorganic component of atmospheric aerosol, does not affect the vapor-liquid exchange mechanism for cloud droplets, despite reducing the saturation vapor pressure of water significantly.

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

    USGS Publications Warehouse

    Wang, A.; Freeman, J.J.; Jolliff, B.L.; Chou, I.-Ming

    2006-01-01

    The martian orbital and landed surface missions, OMEGA on Mar Express and the two Mars Explorations Rovers, respectively, have yielded evidence pointing to the presence of magnesium sulfates on the martian surface. In situ identification of the hydration states of magnesium sulfates, as well as the hydration states of other Ca- and Fe- sulfates, will be crucial in future landed missions on Mars in order to advance our knowledge of the hydrologic history of Mars as well as the potential for hosting life on Mars. Raman spectroscopy is a technique well-suited for landed missions on the martian surface. In this paper, we report a systematic study of the Raman spectra of the hydrates of magnesium sulfate. Characteristic and distinct Raman spectral patterns were observed for each of the 11 distinct hydrates of magnesium sulfates, crystalline and non-crystalline. The unique Raman spectral features along with the general tendency of the shift of the position of the sulfate ??1 band towards higher wavenumbers with a decrease in the degree of hydration allow in situ identification of these hydrated magnesium sulfates from the raw Raman spectra of mixtures. Using these Raman spectral features, we have started the study of the stability field of hydrated magnesium sulfates and the pathways of their transformations at various temperature and relative humidity conditions. In particular we report on the Raman spectrum of an amorphous hydrate of magnesium sulfate (MgSO4??2H2O) that may have specific relevance for the martian surface. ?? 2006 Elsevier Inc. All rights reserved.

  13. Novel processes for anaerobic sulfate production from elemental sulfur by sulfate-reducing bacteria.

    PubMed

    Lovley, D R; Phillips, E J

    1994-07-01

    Sulfate reducers and related organisms which had previously been found to reduce Fe(III) with H(2) or organic electron donors oxidized S to sulfate when Mn(IV) was provided as an electron acceptor. Organisms catalyzing this reaction in washed cell suspensions included Desulfovibrio desulfuricans, Desulfomicrobium baculatum, Desulfobacterium autotrophicum, Desulfuromonas acetoxidans, and Geobacter metallireducens. These organisms produced little or no sulfate from S with Fe(III) as a potential electron acceptor or in the absence of an electron acceptor. In detailed studies with Desulfovibrio desulfuricans, the stoichiometry of sulfate and Mn(II) production was consistent with the reaction S + 3 MnO(2) + 4H-->SO(4) + 3Mn(II) + 2H(2)O. None of the organisms evaluated could be grown with S as the sole electron donor and Mn(IV) as the electron acceptor. In contrast to the other sulfate reducers evaluated, Desulfobulbus propionicus produced sulfate from S in the absence of an electron acceptor and Fe(III) oxide stimulated sulfate production. Sulfide also accumulated in the absence of Mn(IV) or Fe(III). The stoichiometry of sulfate and sulfide production indicated that Desulfobulbus propionicus disproportionates S as follows: 4S + 4H(2)O-->SO(4) + 3HS + 5 H. Growth of Desulfobulbus propionicus with S as the electron donor and Fe(III) as a sulfide sink and/or electron acceptor was very slow. The S oxidation coupled to Mn(IV) reduction described here provides a potential explanation for the Mn(IV)-dependent sulfate production that previous studies have observed in anoxic marine sediments. Desulfobulbus propionicus is the first example of a pure culture known to disproportionate S. PMID:16349323

  14. Novel processes for anaerobic sulfate production from elemental sulfur by sulfate-reducing bacteria

    USGS Publications Warehouse

    Lovley, D.R.; Phillips, E.J.P.

    1994-01-01

    Sulfate reducers and related organisms which had previously been found to reduce Fe(III) with H2 or organic electron donors oxidized S0 to sulfate when Mn(IV) was provided as an electron acceptor. Organisms catalyzing this reaction in washed cell suspensions included Desulfovibrio desulfuricans, Desulfomicrobium baculatum. Desulfobacterium autotrophicum, Desulfuromonas acetoxidans, and Geobacter metallireducens. These organisms produced little or no sulfate from S0 with Fe(III) as a potential electron acceptor or in the absence of an electron acceptor. In detailed studies with Desulfovibrio desulfuricans, the stoichiometry of sulfate and Mn(II) production was consistent with the reaction S0 + 3 MnO2 + 4H+ ???SO42- + 3Mn(II) + 2H2O. None of the organisms evaluated could be grown with S0 as the sole electron donor and Mn(IV) as the electron acceptor. In contrast to the other sulfate reducers evaluated, Desulfobulbus propionicus produced sulfate from S0 in the absence of an electron acceptor and Fe(III) oxide stimulated sulfate production. Sulfide also accumulated in the absence of Mn(IV) or Fe(III). The stoichiometry of sulfate and sulfide production indicated that Desulfobulbus propionicus disproportionates S0 as follows: 4S0 + 4H2O???SO42- + 3HS- + 5 H+. Growth of Desulfobulbus propionicus with S0 as the electron donor and Fe(III) as a sulfide sink and/or electron acceptor was very slow. The S0 oxidation coupled to Mn(IV) reduction described here provides a potential explanation for the Mn(IV)-dependent sulfate production that previous studies have observed in anoxic marine sediments. Desulfobulbus propionicus is the first example of a pure culture known to disproportionate S0.

  15. Aerosol induced reduction in modeled precipitation in China in the late twentieth century

    NASA Astrophysics Data System (ADS)

    Folini, Doris; Wild, Martin

    2015-04-01

    We examine ensembles of transient (1870 - 2005) sensitivity experiments with the global climate model ECHAM5-HAM with particular focus on aerosol induced reduction of precipitation in eastern China in the late twentieth century. In the model employed, the microphysics of stratiform clouds directly couples to aerosols, but not the microphysics of convective clouds. Increasing anthropogenic aerosol emissions in the model result in a reduction of precipitation that is mostly stronger than what is observed. Only in summer increasing aerosol emissions can improve the agreement between modeled and observed trends. The modeled drying is dominated by a decrease in convective precipitation. For the fraction of convective to total precipitation we find a decrease of about 4% to 6% per decade (2% for stratiform precipitation). These percentages are robust against model resolution. Not robust against model resolution are trends of precipitation anomalies (total, convective, or stratiform), which tend to be stronger for lower model resolution. Regarding the relative importance of different aerosols, our simulations suggest sulfate to be more relevant for the precipitation reduction than black and organic carbon.

  16. Acidic precipitation: considerations for an air-quality standard

    SciTech Connect

    Evans, L.S.; Hendrey, G.R.; Stensland, G.J.; Johnson, D.W.; Francis, A.J.

    1980-01-01

    Acidic precipitation, wet or frozen deposition with a hydrogen ion concentration greatern than 2.5 ..mu..eq l/sup -1/ is a significant air pollution problem in the United States. The chief anions accounting for the hydrogen ions in rainfall are nitrate and sulfate. Agricultural systems are more likely to derive net nutritional benefits from increasing inputs of acidic rain than are forest systems when soils alone are considered. Agricultural soils may benefit because of the high N and S requirements of agricultural plants. Detrimental effects to forest soils may result if atmospheric H/sup +/ inputs significantly add to or exceed H/sup +/ production by soils. Acidification of fresh waters of southern Scandinavia, southwestern Scotland, southeastern Canada, and northeastern United States is caused by acid deposition. Areas of these regions in which this acidification occurs have in common, highly acidic precipitation with volume weighted mean annual H/sup +/ concentrations of 25 ..mu..eq l/sup -1/ or higher and slow weathering granitic or precambrian bedrock with thin soils deficient in minerals which would provide buffer capacity. Biological effects of acidification of fresh waters are detectable below pH 6.0. As lake and stream pH levels decrease below pH. 6.0, many species of plants, invertebrates, and vertebrates are progressively eliminated. Generally, fisheries are impacted below pH 5.0 and are completely destroyed below pH 4.8. There are few studies that document effects of acidic precipitation on terrestrial vegetation to establish an air quality standard. It must be demonstrated that current levels of precipitation acidity alone significantly injure terrestrial vegetation. In terms of documented damanges, current research indicates that establishing a standard for precipitation for the volume weighted annual H/sup +/ concentration at 25 ..mu..eq l/sup -1/ may protect the most sensitive areas from permanent lake acidification.

  17. Conditional Generation of Monthly Precipitation

    Microsoft Academic Search

    U. Kim; J. J. Kaluarachchi

    2006-01-01

    Monthly precipitation models can be used in basin-wide modeling to develop long-term strategies for water resources planning and management and to estimate the change of water yield due to climate change. Such precipitation models are especially important for effective management of river basins in developing countries such as the upper Blue Nile River basin of Ethiopia where the water resource

  18. Resistivity Problems in Electrostatic Precipitation

    ERIC Educational Resources Information Center

    White, Harry J.

    1974-01-01

    The process of electrostatic precipitation has ever-increasing application in more efficient collection of fine particles from industrial air emissions. This article details a large number of new developments in the field. The emphasis is on high resistivity particles which are a common cause of poor precipitator performance. (LS)

  19. S-band variable time delay circuit on barium tetratitanate

    NASA Astrophysics Data System (ADS)

    Bellacicco, R. F.

    1981-12-01

    The performance requirements for a variable time delay circuit for use in a phased array antenna are given - time delay from 1/2 to 16 nsec, 3 GHz operating frequency, 20% bandwidth, temperature compensation, and compact size. A brief description is presented of various types of devices which could meet these requirements. In the research for the electrical structure of this time delay circuit, two design types were investigated. The first, a tapped transmission line, yielded poor results on a test circuit - high insertion loss (2-22 db) and high VSWR. The second design was that of a 5-bit network. Test circuit results showed this to be a relatively good design insertion loss of 0.7 - 5.0 db and VSWR of 1.8 and 2.5. A complete time delay circuit design was produced using a 4-bit structure for the RF transmission line (1/2 to 8 nsec in 1/2 nsec increments) and a loaded switched-line structure for selection of the amount of time delay. For temperature compensation, the circuit design was dimensioned for a barium tetratitinate microstrip substrate. Due to small substrate size, the maximum time delay was 8 nsec instead of 16 nsec.

  20. UV integrated optics devices based on beta-barium borate

    NASA Astrophysics Data System (ADS)

    Poberaj, Gorazd; Degl'Innocenti, Riccardo; Medrano, Carolina; Günter, Peter

    2009-05-01

    We report on our recent progress in development of ultraviolet (UV) integrated optics devices based on beta-barium borate (BBO). Planar optical waveguides with a thickness of a few micrometers have been formed by the implantation of He + ions with energies of around 2 MeV. Two alternative methods based on the femtosecond-laser assisted micromachining and lithographic structuring for the fabrication of ridge-type channel optical waveguides in implanted BBO crystals have been developed, and the transmission properties of the obtained waveguides have been studied. We demonstrate a big potential of the fabricated channel waveguides for the second harmonic generation of continuous-wave deep-UV laser light with a power of the order of 1 mW, exploiting the nonlinear optical properties of BBO crystal. In addition, a low-voltage electro-optic waveguide modulator for the deep-UV light (half-wave voltage times electrode length V? × l = 43 V cm at 257 nm) was realized for the first time.