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Sample records for barium sulfate particles

  1. Barium Sulfate

    Science.gov (United States)

    Barium sulfate is used to help doctors examine the esophagus (tube that connects the mouth and stomach), ... dimensional pictures of the inside of the body). Barium sulfate is in a class of medications called ...

  2. Barium Sulfate

    Science.gov (United States)

    ... using x-rays or computed tomography (CAT scan, CT scan; a type of body scan that uses ... be clearly seen by x-ray examination or CT scan. ... more times before an x-ray examination or CT scan.If you are using a barium sulfate ...

  3. Recrystallization of 223Ra with barium sulfate

    International Nuclear Information System (INIS)

    In this work, the kinetics of barium sulfate recrystallization has been studied in acidic 0.01 mol dm-3 sodium sulfate solution using 223Ra and 133Ba tracers at very low total radium concentration, i.e. less than 10-13 mol dm-3. It was found that the system follows the homogeneous recrystallization model and that recrystallization rates, inferred by the decrease of 223Ra and 133Ba in the aqueous solution, are fast. Therefore, even at very low concentrations, below the solubility limit, radium will be retained by barium sulfate-a mineral present in the deep underground repository. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, S.; Patrick, G.

    1987-06-01

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

  5. Economically dissolving barium sulfate scale with a chelating agent

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, E.A.; Scheuerman, R.E.

    1977-06-21

    A composition is described for dissolving a barium sulfate scale from a subterranean or other relatively remote location into which fluid can be flowed. Fluid is flow-flowed into the remote location so that a stream of fluid contacts and flows along the surface of the scale. The composition and flow rate of the fluid are adjusted so that (1) the scale is contacted by a stream of aqueous solution in which each portion contains enough dissolved aminopolyacetic acid salt chelating agent to dissolve barium sulfate, and (2) substantially all upstream portions of the scale are contacted by a succession of portions of the aqueous liquid which are substantially unsaturated with respect to dissolved barium-chelant complex. (5 claims)

  6. The adhesiometer: a simple device to measure adherence of barium sulfate to intestinal mucosa.

    Science.gov (United States)

    Salomonowitz, E; Frick, M P; Cragg, A H; Lund, G

    1984-04-01

    A simple, inexpensive device assessing barium sulfate adherence to alimentary tract mucosa was tested in an animal study using pigs and dogs. Interaction of gastric, intestinal, and colonic mucosal lining with three different barium preparations was studied. In both pigs and dogs, barium adherence to gastric mucosa was significantly stronger when compared with colonic mucosa. PMID:6608230

  7. Barium sulfate suspension as a negative oral contrast agent for MR imaging

    International Nuclear Information System (INIS)

    Proton spectroscopy with linewidth measurements and MR imaging were performed on various commercially available barium sulfate suspensions as well as inorganic sulfates and barium salts. Approximately 500 mL of 20%, 40%, 60%, and 70% wt/wt single-contrast oral barium sulfate suspensions were administered to four normal volunteers, and MR imaging was performed with both a 1.5-T and a 0.15-T MR imager. As much as 80% of the small bowel and the entire colon were well visualized with the 60% or 70% wt/wt single-contrast barium sulfate suspensions. The authors conclude that barium sulfate suspensions are useful as oral MR contrast agents

  8. EPR dosimetric properties of nano-barium sulfate

    International Nuclear Information System (INIS)

    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 γ-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 γ-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. - Highlights: • Preparation of nano-BaSO4 using the co-precipitation method. • Study of the dosimetric properties of nano-barium sulfate using the EPR technique. • Comparison between a new EPR dosimeter using nano-materials and standard alanine. • Calculation of the uncertainty budget for nano-BaSO4

  9. Morphologies, mechanical properties and thermal stability of poly(lactic acid) toughened by precipitated barium sulfate

    Science.gov (United States)

    Yang, Jinian; Wang, Chuang; Shao, Kaiyun; Ding, Guoxin; Tao, Yulun; Zhu, Jinbo

    2015-11-01

    Poly(lactic acid) (PLA)-based composites were prepared by blending PLA with precipitated barium sulfate (BaSO4) modified with stearic acid. The morphologies, mechanical properties and thermal stability of samples with increased mass fraction of BaSO4 were investigated. Results showed that PLA was toughened and reinforced simultaneously by incorporation of precipitated BaSO4 particles. The highest impact toughness and elongation at break were both achieved at 15% BaSO4, while the elastic modulus increased monotonically with increasing BaSO4 loading. Little effect of BaSO4 on the thermal behavior of PLA was observed in the present case. However, the thermal stability of PLA/BaSO4 composites at high temperature was enhanced.

  10. The Precipitation Process of Liquid Wastes Containing Contaminant Am withBarium Sulfate

    International Nuclear Information System (INIS)

    The investigated of the reduction volume liquid wastes containing ofAmericium nuclide contaminant has been done. The reduction volume was done byadding barium sulfate coagulant. The experimental procedure that has beendone by adding regent of barium nitrate and natrium sulfate to the wasteswith its preadjusted pH, then by utilizing the jar test equipment was carriedout the fast stirring speed for 5 minutes and the gentle agitation for 30minutes, therefor its floc and supernatant will be formed. The resultedbarium sulfate floc will trap radionuclide in the wastes. The Variableinvestigated were: the concentration of barium sulfate, pH of the wastes, theflash mixing rate, the gentle agitation rate. The investigated barium sulfateconcentration variable was started from 100 ppm up to 800 ppm. Theinvestigated pH variable was started from pH 7 up to pH 13. The investigatedflash mixing rate were 75, 100, 125, 150, 175, 200, 225, 250 rpm. Theinvestigated gentle agitation variable were 20, 30, 40, 50 rpm. The bestresult which was represented by decontaminating factor (DF) was found frombarium sulfate concentration of 300 ppm and pH 11, and the flash mixing rateof 200 rpm and the gentle agitation rate of 20 rpm, with the separationefficiency = 97.2 %. (author)

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

    OpenAIRE

    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...

  12. Barium

    International Nuclear Information System (INIS)

    Present article is devoted to barium content in fluoride. In order to obtain the comprehensive view on barium distribution in fluorite 303 mono mineral fractions of various geologic deposits and ores of Kazakhstan, Uzbekistan, Tajikistan and some geologic deposits of Russia were analyzed. The barium content in fluorite of geologic deposits of various mineralogical and genetic type was defined. The basic statistical estimation of barium distribution in fluorite were evaluated.

  13. HYBRID AND CHARACTERISTIC OF POLYANILINE- BARIUM TITANATE NANOCOMPOSITE PARTICLES

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Polyaniline-barium titanate (PAn-BaTiO3) ultrafine composite particles were prepared by the oxidative polymerization of aniline with H2O2 while barium titanate nanoparticles were synthesized with a sol-gel method. The infrared spectrogram shows that the polymerization of PAn in the hybrid process of PAn-BaTiO3 is similar with the polymeric process of pure aniline, and there is interaction of PAn and BaTiO3 in the PAn-BaTiO3. SEM and TEM results show that the average diameter of the composite particles is 1.50 μm and the diameters of BaTiO3 nanoparticles are 5-15 nm in the composite particle. The electrical conductivity of the ultrafine composite particles is transformable from 100 to 10-11S/cm by equilibrium doping or dedoping method using various concentration of HCl or NaOH solutions.

  14. Preparation and Characterization of Nano-particle Substituted Barium Hexaferrite

    OpenAIRE

    Atassi, Yomen; Darwich, Iyad Seyd; Tally, Mohammad

    2014-01-01

    High density magnetic recording requires high coercivity magnetic media and small particle size. Barium hexaferrite has been considered as a leading candidate material because of its chemical stability, fairly large crystal anisotropy and suitable magnetic characteristics. In this work, we present the preparation of the hexagonal ferrite BaFe12O19 and one of its derivative; the Zn-Sn substituted hexaferrite by the chemical co-precipitation method. The main advantage of this method on the conv...

  15. Barium enema

    Science.gov (United States)

    Barium enema is a special x-ray of the large intestine, which includes the colon and rectum. ... to a bag that holds a liquid containing barium sulfate. This is a contrast material that highlights ...

  16. Measurement of microbic contamination rate in the dispensing process making suspension of barium sulfate powder

    International Nuclear Information System (INIS)

    The purpose of this study is to investigate the contamination rate of barium sulfate suspension made in the exposed state in usual circumstances. This study was performed in four university hospital using the contrast media by barium sulfate powder. The specimen were detected at dispensing water, agitator and mixing tank. We also classified the suspension into general bacteria, mycete and Bacillus coli infection. The tap water were used to dispense water in the all hospitals. Bacillus coli were not detected in the all. General bacteria and mycete were not detected in the one specimen, but detected in two specimen over defined value. In the contamination rate of agitator, mixing tank, and the manufactured. Bacillus coli were not detected in all. However, general bacteria and mycete were detected too numberous to count. In conclusion, the refined water must be used in dispensing water in manufacturing suspension. The disinfectant is also used in washing the agitator and mixing tank for sterilization. Hand washing is indispensable to manufacturing suspension for preventing from infection

  17. Contrast radiography in small bowel obstruction. A randomized trial of barium sulfate and a nonionic low-osmolar contrast medium

    International Nuclear Information System (INIS)

    Thirty-six adult patients clinically suspected of small bowel obstruction underwent small bowel contrast radiography with either barium sulfate or a nonionic low-osmolar contrast medium after randomization. Films were taken after 2, 4, and 8 hours and later when needed. No difference as regards visualization and diagnostic quality was found between the 2 media. It is concluded that a nonionic low-osmolar contrast medium is an alternative to barium sulfate for small bowel contrast radiography where small bowel obstruction is suspected. (orig.)

  18. Preparation and Characterization of Nano-particle Substituted Barium Hexaferrite

    CERN Document Server

    Atassi, Yomen; Tally, Mohammad

    2014-01-01

    High density magnetic recording requires high coercivity magnetic media and small particle size. Barium hexaferrite has been considered as a leading candidate material because of its chemical stability, fairly large crystal anisotropy and suitable magnetic characteristics. In this work, we present the preparation of the hexagonal ferrite BaFe12O19 and one of its derivative; the Zn-Sn substituted hexaferrite by the chemical co-precipitation method. The main advantage of this method on the conventional glass-ceramic one, resides in providing a small enough particle size for magnetic recording. We demonstrate using the X-ray diffraction patterns that the particle size decreases when substituting the hexaferrite by the Zn-Sn combination. This may improve the magnetic properties of the hexaferrite as a medium for HD magnetic recording

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

    CERN Document Server

    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 ...

  20. Evaluation of radiation dose reduction during CT scans by using bismuth oxide and nano-barium sulfate shields

    Science.gov (United States)

    Seoung, Youl-Hun

    2015-07-01

    The purpose of the present study was to evaluate the radiation dose reduction and the 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 bismuth oxide (Bi2O3) particles. The radiation dose was measured five times at a direction of 12 o'clock from the center of the polymethyl methacrylate (PMMA) head phantom by using a CT ionization chamber to calculate an average value. The image quality of measured CT transverse images of the PMMA head phantom depended on the X-ray tube voltage and the type of shielding. Two regions of interest in the CT transverse images were chosen, one from the right area and the other from the left area under the surface of the PMMA head phantom and at a distance of ion chamber holes located in a direction 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 the dosages by 15.61%, 23.05%, and 22.71% at 90 kVp, 120 kVp, and 140 kVp, respectively, than with these of a conventional bismuth shield of the same thickness while maintaining image quality. In addition, the DRFSs produced were about 25% thinness than conventional bismuth. We conclude, therefore, that a DRFS can replace conventional bismuth as a new shield.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. Experimental design: application to the development of a treatment to inhibit the deposition of barium sulfate liable to be formed in enhanced oil recovery by waterflooding

    Energy Technology Data Exchange (ETDEWEB)

    Messaoudene, N. (Sonatrach, Boumerdes (Algeria)); Puech-Costes, E.; Maurette, M.T. (Toulouse-3 Univ., 31 (France)); Girou, A. (Institut National des Sciences Appliquees (INSA), 31 - Toulouse (France)); Roque, C. (Institut Francais du Petrole (IFP), 92 - Rueil-Malmaison (France))

    For technical and economic reasons, waterflooding is the most widely-used method in enhanced oil recovery. In many situations, unfortunately, the formation water is incompatible with the injection water. The deposits and corrosion induced by the various reactions of this incompatibility cause irreversible damage, which is especially dangerous for the reservoir rock and the downhole and surface production facilities. This study is concerned exclusively with barium sulfate deposits liable to occur in surface production facilities by the mixing of injection water loaded with sulfate (1300 mg.l[sup -1]) with a formation water with a high barium concentration (1200 mg.l[sup -1]). 6 refs., 6 figs., 7 tabs.

  3. Barium and strontium sulfate solid solution formation in relation to North Sea scaling problems

    International Nuclear Information System (INIS)

    This paper presents the results of laboratory experiments carried out to investigate barium sulphate and strontium sulphate solid solution formation in multi-pressure tapped cores. Two brines, one barium and strontium rich and the other sulphate rich, were mixed in a core plug. Pressure differentials were measured and the changing permeability distribution along the length of the core calculated. The morphology and chemical analysis of scaling crystals are presented based on Scanning electron Microsocpy (SEM) and Energy Dispersive X-ray Analysis (EDAX). The results show the large extent of permeability damage caused by (Ba, SR) SO/sub 4/ solid solution depositing on the rock pore surface. The rock permeability decline and morphology and size of the scaling crystals indicate the influence of the supersaturations of BaSO/sub 4/ and SrSO/sub 4/ as well as the concentration ratio of barium ions to strontium ions

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

    Science.gov (United States)

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

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

    International Nuclear Information System (INIS)

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

  6. Effects of barium sulfate as a contrast medium to enterocutaneous fistulas

    International Nuclear Information System (INIS)

    Fistulation following thoracic and epigastric interventions are conservatively treated, as a rule, because of the high rate of complications expected from reoperation. With properly functioning anastomotic transit, insufficiencies usually undergo spontaneous healing, within four to six weeks. Enterocutaneous fistulae developed in 29 of 271 patients with intrathoracic oesophagastric or oesophagojejunal anastomosis. Syringeal ramification into pleural or abdominal cavities were eliminated by means of an absorbable contrast medium, before barium sulphate was orally administered to all patients. Thoracic fistulae were closed after 21.8 days on average, while 20.3 days was the average period required for closure of epigastric fistulae. Barium sulphate was found to stimulate fistular tissue granulation, so that obliteration of the fistular system occurred much sooner, as compared to conservative treatment. The patient's quality of life can thus be improved, and hospitalisation can be shortened. Neither locally delimited nor systemic complications were observed in any of the cases described. (author)

  7. Numerical investigation of the influence of kinetics and shape factor on barium sulfate precipitation in a continuous stirred tank

    Institute of Scientific and Technical Information of China (English)

    Zheng WANG; ZaiSha MAO; Chao YANG; Qinghua ZHANG; Jingcai CHENG

    2009-01-01

    The effect of kinetics and shape factor on barium sulfate precipitation in a continuous stirred tank has been investigated numerically through solving the standard momentum and mass transport equations in combination with the moment equations for crystal population balance. The numerical method was validated with the literature data. The simulated results include the distribution of the local supersaturation ratio in the reactor, the mean crystal size, and the coefficient of variation. The simulation results show that the value of shape factor used in the model affected greatly the mean crystal size and the moments of the crystal size distribution. The influence of the kinetic expressions on the simulation is also analyzed. It is important to investigate the relationship of the shape factor with the precipitator type and other operation conditions to obtain reliable simulation results and suitable kinetic equations of crystal nucleation and growth rates.

  8. Direct large-scale synthesis of perovskite barium strontium titanate nano-particles from solutions

    International Nuclear Information System (INIS)

    This paper reports a wet chemical synthesis technique for large-scale fabrication of perovskite barium strontium titanate nano-particles near room temperature and under ambient pressure. The process employs titanium alkoxide and alkali earth hydroxides as starting materials and involves very simple operation steps. Particle size and crystallinity of the particles are controllable by changing the processing parameters. Observations by X-ray diffraction, scanning electron microscopy and transmission electron microscopy TEM indicate that the particles are well-crystallized, chemically stoichiometric and ∼50nm in diameter. The nanoparticles can be sintered into ceramics at 1150 deg. C and show typical ferroelectric hysteresis loops

  9. BARIUM RECOVERY PROCESS

    Science.gov (United States)

    Blanco, R.E.

    1959-07-21

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

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

    OpenAIRE

    Monnin, Christophe; Balleur, Sabine; Goffé, Bruno

    2003-01-01

    We have used a new thermodynamic model of barium and calcium sulfate solubilities in multicomponent electrolyte solutions (Monnin, 1999) to investigate the stabilities of barite and anhydrite in seawater or in marine sediment porewaters at high temperature and pressure. As a further test supplementing those previously carried out during model development, we have calculated the temperature at which standard seawater becomes saturated with respect to anhydrite. The model predicts that, upon he...

  11. Determination of carbon in amorphous carbon and uranium monocarbide by oxidation with lead(IV) oxide, copper(II) oxide or barium sulfate in an inert atmosphere

    International Nuclear Information System (INIS)

    Oxidation behavior was studied on amorphous carbon and carbon in uranium monocarbide when lead(IV) oxide, copper(II) oxide and barium sulfate were used as the oxidizing fluxes in helium. The amorphous carbon and the carbon in the carbide were completely extracted with lead oxide in 5 min at 10000C and in 8 min at 700 and 5000C, respectively. Carbon in two samples was quantitatively extracted at 10000C with copper oxide in 8 and 5 min, and with barium sulfate in 7 and 5 min, respectively. The rate of extraction of carbon with copper oxide decreased with decreasing temperature. It was found that the mixing ratio of the oxidizing flux to the amorphous carbon or carbide gave effect on the recovery of carbon. The conventional capillary-trap method which is used for the determination of carbon has a disadvantage that, when carbon dioxide is caught in a cold trap (liquid nitrogen), oxygen is also trapped. This disadvantage was eliminated when a stream of helium was used in place of oxygen. Carbon in the sample can be determined with lead oxide, copper oxide or barium sulfate by extracting carbon dioxide at 10000C for 10 min. (auth.)

  12. Influence of fuel ratios on auto combustion synthesis of barium ferrite nano particles

    Indian Academy of Sciences (India)

    D Bahadur; S Rajakumar; Ankit Kumar

    2006-01-01

    Single-domain barium ferrite nano particles have been synthesized with narrow particle-size distribution using an auto combustion technique. In this process, citric acid was used as a fuel. Ratios of cation to fuel were maintained variously at 1 : 1, 1 : 2 and 1 : 3. The pH was 7 in all cases. Of all three cases, a cation to citric acid ratio of 1 : 2 gives better yield in the formation of crystalline and single domain particles with a narrow range of size distribution. Most particles are in the range of 80 to 100 nm. Maximum magnetization and coercivity values are also greater for 1 : 2 ratios. These values measured at room temperature are found to be 55 emu/gram and 5000 Oe respectively. XPS and ESR studies support the results.

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

    Science.gov (United States)

    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 δ18O 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 δ18O values of the H2O, NO, and SO. Typical δ18O 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 δ17O and Δ17O. 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 δ18O 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.

  14. Curie temperature and magnetic properties of aluminum doped barium ferrite particles prepared by ball mill method

    International Nuclear Information System (INIS)

    Barium ferrite has attracted considerable interest in the fields of permanent magnets and perpendicular magnetic recording due to its strong uniaxial anisotropy and high Curie temperature (Tc). We prepared aluminum doped barium ferrite ceramics (BaAlxFe12−xO19, 0≤x≤6) by the ball mill method. The powder was milled for 96 h, and after forming pellets, annealed for 48 h in air at 1000 °C. The X-ray diffraction (XRD) data show that there are only single hexagonal phases in the samples without any impurity phase. The crystal lattice constants, a and c, were calculated by Cohen's method. Both a and c decrease with increasing x, ranging from 0.588 nm and 2.318 nm to 0.573 nm and 2.294 nm, respectively. A Vibrating Sample Magnetometer (VSM) and Superconducting Quantum Interference Device (SQUID) were used to investigate Tc and magnetic properties of BaFe12−xAlxO19. It is found that Tc decreases with increasing x, from 425 °C to 298 °C. It is also found that the saturated magnetization (4πMs) decreases with increasing x, while the coercivity (Hc) increases with the increase in x. The anisotropy field was also determined from the SQUID measurement. - Highlights: • The Curie temperature and magnetic properties of aluminum doped barium ferrite particles were studied systemically. • The relation between 4πMs and composition x at 50 K (both experimental value and theoretical calculation) was revealed. • Occupation number for spin up and spin down as a function of temperature was shown. • The relation between 4πMs and composition x from 50 K to room temperature was revealed

  15. Curie temperature and magnetic properties of aluminum doped barium ferrite particles prepared by ball mill method

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Daming [Center for Magnetism and Magnetic Nanostructures, University of Colorado at Colorado Springs, 1420 Austin Bluffs Pkwy, Colorado Springs, Colorado 80918 (United States); College of Materials and Chemical Engineering, Hainan University, Haikou 570228, Hainan (China); Harward, Ian; Baptist, Joshua; Goldman, Sara; Celinski, Zbigniew [Center for Magnetism and Magnetic Nanostructures, University of Colorado at Colorado Springs, 1420 Austin Bluffs Pkwy, Colorado Springs, Colorado 80918 (United States)

    2015-12-01

    Barium ferrite has attracted considerable interest in the fields of permanent magnets and perpendicular magnetic recording due to its strong uniaxial anisotropy and high Curie temperature (T{sub c}). We prepared aluminum doped barium ferrite ceramics (BaAl{sub x}Fe{sub 12−x}O{sub 19}, 0≤x≤6) by the ball mill method. The powder was milled for 96 h, and after forming pellets, annealed for 48 h in air at 1000 °C. The X-ray diffraction (XRD) data show that there are only single hexagonal phases in the samples without any impurity phase. The crystal lattice constants, a and c, were calculated by Cohen's method. Both a and c decrease with increasing x, ranging from 0.588 nm and 2.318 nm to 0.573 nm and 2.294 nm, respectively. A Vibrating Sample Magnetometer (VSM) and Superconducting Quantum Interference Device (SQUID) were used to investigate T{sub c} and magnetic properties of BaFe{sub 12−x}Al{sub x}O{sub 19}. It is found that T{sub c} decreases with increasing x, from 425 °C to 298 °C. It is also found that the saturated magnetization (4πM{sub s}) decreases with increasing x, while the coercivity (H{sub c}) increases with the increase in x. The anisotropy field was also determined from the SQUID measurement. - Highlights: • The Curie temperature and magnetic properties of aluminum doped barium ferrite particles were studied systemically. • The relation between 4πM{sub s} and composition x at 50 K (both experimental value and theoretical calculation) was revealed. • Occupation number for spin up and spin down as a function of temperature was shown. • The relation between 4πM{sub s} and composition x from 50 K to room temperature was revealed.

  16. A study of the Arrhenius behavior of the co-precipitation of radium, barium and strontium sulfate

    International Nuclear Information System (INIS)

    Co-precipitation of radium, barium and strontium is an important process in many contexts, such as uranium mining, oil extraction and in the safety assessment of a final repository for used nuclear fuel. Co-precipitation to a solid solution is possible since radium, barium and strontium act as chemical analogues. In this work the co-precipitation of radium, barium and strontium was studied and the kinetic behavior of the co-precipitation process was investigated. It was shown that radium, barium and strontium co-precipitate congruently and that the precipitation followed an Arrhenius behavior and the Arrhenius parameters for the systems was determined. When studying the differences of the Arrhenius constants by using a student t test (95 % confidence interval) it was observed that the only significant difference in the activation energy, Ea, is between radium and barium and between radium and strontium respectively, the pure strontium having the larger activation energy in comparison. This is most likely coupled to the metal ion size; since the hydration waters are more strongly bound, which leads to them having a slower exchange rate, which in turn effects the rate of co-precipitation to the metal these reactions will be slower. (author)

  17. A Simple Method Based on the Application of a CCD Camera as a Sensor to Detect Low Concentrations of Barium Sulfate in Suspension

    Science.gov (United States)

    de Sena, Rodrigo Caciano; Soares, Matheus; Pereira, Maria Luiza Oliveira; da Silva, Rogério Cruz Domingues; do Rosário, Francisca Ferreira; da Silva, Joao Francisco Cajaiba

    2011-01-01

    The development of a simple, rapid and low cost method based on video image analysis and aimed at the detection of low concentrations of precipitated barium sulfate is described. The proposed system is basically composed of a webcam with a CCD sensor and a conventional dichroic lamp. For this purpose, software for processing and analyzing the digital images based on the RGB (Red, Green and Blue) color system was developed. The proposed method had shown very good repeatability and linearity and also presented higher sensitivity than the standard turbidimetric method. The developed method is presented as a simple alternative for future applications in the study of precipitations of inorganic salts and also for detecting the crystallization of organic compounds. PMID:22346607

  18. A Simple Method Based on the Application of a CCD Camera as a Sensor to Detect Low Concentrations of Barium Sulfate in Suspension

    Directory of Open Access Journals (Sweden)

    Joao Francisco Cajaiba da Silva

    2011-01-01

    Full Text Available The development of a simple, rapid and low cost method based on video image analysis and aimed at the detection of low concentrations of precipitated barium sulfate is described. The proposed system is basically composed of a webcam with a CCD sensor and a conventional dichroic lamp. For this purpose, software for processing and analyzing the digital images based on the RGB (Red, Green and Blue color system was developed. The proposed method had shown very good repeatability and linearity and also presented higher sensitivity than the standard turbidimetric method. The developed method is presented as a simple alternative for future applications in the study of precipitations of inorganic salts and also for detecting the crystallization of organic compounds.

  19. Fundamental study of positive contrast media of hepatic CT by micro-barium sulphate particles

    International Nuclear Information System (INIS)

    Hepatic computed tomography (CT) values associated with iv injection of micro-barium sulphate particles (BSP) were examined. Two ml/kg of 10 % solution of BSP 0.3 μ and 1.2 μ in size was iv injected into ten rats. The mean hepatic CT values immediately after injection of 0.3 and 1.2 μ BSP were 2.3 and 2.7 times higher, respectively, than those before that. The subsequent CT values decreased with time. The CT values 30 and 120 days after injection decreased to one half and one fifth of those immediately after that. Histological study of the liver found the enhancement of hepatic CT to be due to increased phagocytic activity of Kupffer cells in the periportal region. In addition, it should be suggested that CT values would decrease with decreasing not only BSP release from Kupffer cells into the extracellular space but also the number of Kupffer cells themselves. (Namekawa, K.)

  20. Rapid determination of sodium sulfate content in tannin extract desulfurization solution by barium magnesium method%钡镁法快速测定栲胶脱硫液中硫酸钠的含量

    Institute of Scientific and Technical Information of China (English)

    李琼

    2011-01-01

    采用GB/T10535--1997仲裁法分析栲胶脱硫液中Na2SO。含量需3h。采用钡镁法以过量已知浓度钡镁混合液与Na2SO4作用生成硫酸钡沉淀,过量钡镁溶液用EDTA标准溶液回滴,只需0.5h,可快速测定硫酸钠含量:该法准确度、精密度也可满足生产要求。%The arbitration method of GB/T 10535--1997 for determination of sodium sulfate content in tannin extract desulfurization solutions needs 3 hours. By using excess known concentrations barium magnesium solutions and sodium sulfate to produce barium sulfate precipitation, and using EDTA to titrate the excessive barium magnesium solutions, the rapid determination of sodium sulfate content only needs 30 minutes. The accuracy and precision can also meet the production requirements.

  1. An Instrument to Measure Aircraft Sulfate Particle Emissions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Aerodyne is developing a sulfate detection instrument, based on the Tunable Infrared Laser Differential Absorption Spectrophotometer (TILDAS) technology and...

  2. MR Colonography with fecal tagging: Barium vs. barium ferumoxsil

    DEFF Research Database (Denmark)

    Achiam, M.P.; Chabanova, E.; Logager, V.B.; Thomsen, H.S.; Rosenberg, J.

    2008-01-01

    . Materials and Methods. Twenty patients referred to CC underwent dark lumen MRC prior to the colonoscopy. Two groups of patients received two different oral contrast agents (barium sulfate and barium sulfate/ferumoxsil) as a laxative-free fecal tagging prior to the MRC. After MRC, the contrast agent was...... rated qualitatively (with the standard method using contrast-to-wall ratio) and subjectively (using a visual analog scale [VAS]) by three different blinded observers. Results. Evaluated both qualitatively and subjectively, the tagging efficiency of barium sulfate/ferumoxsil was significantly better (P...... <.05) than barium sulfate alone. The VAS method for evaluating the tagging efficiency of contrast agents showed a high correlation (observer 11, r = 0.91) to the standard method using contrast-to-wall ratio and also a high interclass correlation (observer 11 and III = 0.89/0.85). MRC found I of 22 (5...

  3. Formation of solid particles from aqueous solutions of palladium sulfate and of palladium sulfate-silver sulfate by gamma ray irradiation

    International Nuclear Information System (INIS)

    Aqueous solutions containing (a) palladium sulfate (b) palladium sulfate and silver sulfate, and (c) silver sulfate saturated with nitrogen were irradiated with cobalt 60 gamma radiations (dose rate, 2.35 and 11.2 kGy/h; temperature: 10 and 29-45degC). The pH's of the most solutions were 1.43 or 0.43. Formation of fine particles was studied from the decrease of optical absorption of the metal ions, and from mass measurement of solid precipitate. It was found that (1) palladium ion decreased with dose in the solutions (a) and (b) with appearance of continuum spectra from 200-700nm range due to solid particles, and (2) silver ion decreased with increasing dose in solution (b) while it did not decrease in solution (c), and (3) electric conductive precipitate was formed in solution (a) and solution (b), but no precipitate was found in solution (c) by the irradiation. The results indicate that (1) palladium ion was reduced to form metallic precipitate in any condition studied, but (b) silver ion was reduced only in the presence of palladium ion, and (3) bimetallic particles were formed in solution (b). The amounts of the precipitates recovered from the irradiated solutions were 57% for solution (a) and 97% for (b) of the amounts of ions reacted. (author)

  4. An Instrument to Measure Aircraft Sulfate Particle Emissions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Aircraft particle emissions contribute a modest, but growing, portion of the overall particle emissions budget. Characterizing aircraft particle emissions is...

  5. Template-Engaged Solid-State Synthesis of Barium Magnesium Silicate Yolk@Shell Particles and Their High Photoluminescence Efficiency.

    Science.gov (United States)

    Chen, Xuncai; Kim, Woo-Sik

    2016-05-17

    This study presents a new synthetic method for fabricating yolk@shell-structured barium magnesium silicate (BMS) particles through a template-engaged solid-state reaction. First, as the core template, (BaMg)CO3 spherical particles were prepared based on the coprecipitation of Ba(2+) and Mg(2+) . These core particles were then uniformly shelled with silica (SiO2 ) by using CTAB as the structure-directing template to form (BaMg)CO3 @SiO2 particles with a core@shell structure. The (BaMg)CO3 @SiO2 particles were then converted to yolk@shell barium magnesium silicate (BMS) particles by an interfacial solid-state reaction between the (BaMg)CO3 (core) and the SiO2 (shell) at 750 °C. During this interfacial solid-state reaction, Kirkendall diffusion contributed to the formation of yolk@shell BMS particles. Thus, the synthetic temperature for the (BaMg)SiO4 :Eu(3+) phosphor is significantly reduced from 1200 °C with the conventional method to 750 °C with the proposed method. In addition, the photoluminescence intensity of the yolk@shell (BaMg)SiO4 :Eu(3+) phosphor was found to be 9.8 times higher than that of the conventional (BaMg)SiO4 :Eu(3+) phosphor. The higher absorption of excitation light by the structure of the yolk@shell phosphor is induced by multiple light-reflection and -scattering events in the interstitial void between the yolk and the shell. When preparing the yolk@shell (BaMg)SiO4 :Eu(3+) phosphor, a hydrogen environment for the solid-state reaction results in higher photoluminescence efficiency than nitrogen and air environments. The proposed synthetic method can be easily extended to the synthesis of other yolk@shell multicomponent metal silicates. PMID:27059894

  6. In-cloud sulfate addition to single particles resolved with sulfur isotope analysis during HCCT-2010

    Science.gov (United States)

    Harris, E.; Sinha, B.; van Pinxteren, D.; Schneider, J.; Poulain, L.; Collett, J.; D'Anna, B.; Fahlbusch, B.; Foley, S.; Fomba, K. W.; George, C.; Gnauk, T.; Henning, S.; Lee, T.; Mertes, S.; Roth, A.; Stratmann, F.; Borrmann, S.; Hoppe, P.; Herrmann, H.

    2014-04-01

    In-cloud production of sulfate modifies aerosol size distribution, with important implications for the magnitude of indirect and direct aerosol cooling and the impact of SO2 emissions on the environment. We investigate which sulfate sources dominate the in-cloud addition of sulfate to different particle classes as an air parcel passes through an orographic cloud. Sulfate aerosol, SO2 and H2SO4 were collected upwind, in-cloud and downwind of an orographic cloud for three cloud measurement events during the Hill Cap Cloud Thuringia campaign in autumn 2010 (HCCT-2010). Combined SEM and NanoSIMS analysis of single particles allowed the δ34S of particulate sulfate to be resolved for particle size and type. The most important in-cloud SO2 oxidation pathway at HCCT-2010 was aqueous oxidation catalysed by transition metal ions (TMI catalysis), which was shown with single particle isotope analyses to occur primarily in cloud droplets nucleated on coarse mineral dust. In contrast, direct uptake of H2SO4 (g) and ultrafine particulate were the most important sources modifying fine mineral dust, increasing its hygroscopicity and facilitating activation. Sulfate addition to "mixed" particles (secondary organic and inorganic aerosol) and coated soot was dominated by in-cloud aqueous SO2 oxidation by H2O2 and direct uptake of H2SO4 (g) and ultrafine particle sulfate, depending on particle size mode and time of day. These results provide new insight into in-cloud sulfate production mechanisms, and show the importance of single particle measurements and models to accurately assess the environmental effects of cloud processing.

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

    Science.gov (United States)

    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.

  8. Heterogeneous Nucleation and Growth of Barium Sulfate at Organic–Water Interfaces: Interplay between Surface Hydrophobicity and Ba 2+ Adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Chong; Stack, Andrew G.; Koishi, Ayumi; Fernandez-Martinez, Alejandro; Lee, Sang Soo; Hu, Yandi

    2016-05-31

    Barium sulfate (BaSO4) is a common scale-forming mineral in natural and engineered systems, yet the rates and mechanisms of heterogeneous BaSO4 nucleation are not understood. To address these, we created idealized interfaces on which to study heterogeneous nucleation rates and mechanisms, which also are good models for organic–water interfaces: self-assembled thin films terminated with different functional groups (i.e., -COOH, -SH, or mixed -SH & COOH) coated on glass slides. BaSO4 precipitation on coatings from Barite-supersaturated solutions (saturation index, SI, = 1.1) was investigated using grazing-incidence small-angle X-ray scattering. After reaction for 1 h, a little amount of BaSO4 formed on hydrophilic bare and -COOH coated glasses. Meanwhile, BaSO4 nucleation was significantly promoted on hydrophobic -SH and mixed -SH & COOH coatings. This is because substrate hydrophobicity likely affected the interfacial energy and hence thermodynamic favorability of heterogeneous nucleation. The heterogeneous BaSO4 nucleation and growth kinetics were found to be affected by the amount of Ba2+ adsorption onto the substrate and incipient BaSO4 nuclei. The importance of Ba2+ adsorption was further corroborated by the finding that precipitation rate increased under [Ba2+]/[SO42–] concentration ratios >1. These observations suggest that thermodynamic favorability for nucleation is governed by substrate–water interfacial energy, while given favorable thermodynamics, the rate is governed by ion attachment to substrates and incipient nuclei.

  9. Eu-doped barium strontium silicate phosphor particles prepared from spray solution containing NH4Cl flux by spray pyrolysis

    International Nuclear Information System (INIS)

    Eu-doped barium strontium silicate phosphor particles with high photoluminescence intensity under long wavelength ultraviolet were prepared from the spray solution containing NH4Cl flux by spray pyrolysis. It was found that the addition of NH4Cl to the spray solution makes it possible to greatly improve the photoluminescence intensity of Ba1.488Sr0.5SiO4:Eu0.012 phosphor particles under long wavelength ultraviolet of 410 nm. The highest photoluminescence intensity, which was achieved when the NH4Cl content was 5 wt.%, was about 150% of Ba1.488Sr0.5SiO4:Eu0.012 particles prepared from the spray solution without flux material at the post-treatment temperature of 1050 deg. C. The particle size of Ba1.488Sr0.5SiO4:Eu0.012 phosphor particles were enlarged by using the NH4Cl flux in the spray solution because of the large grain growth which was identified from the sharpening of the XRD peaks. Adding the NH4Cl flux into the spray solution was found to lower the optimal post-treatment temperature at which the Ba1.488Sr0.5SiO4:Eu0.012 phosphor particles are fully crystallized and have the maximum photoluminescence intensity. The phosphor particles prepared from spray solution containing 5 wt.% NH4Cl flux had the maximum photoluminescence intensity at post-treatment temperature of 1100 deg. C

  10. An experimental study on barium peritonitis in rats

    International Nuclear Information System (INIS)

    Barium sulfate is universally used contrast media in gastrointestinal roentgenology, and spillage of barium into peritoneal cavity can occur. The references on effect of barium sulfate in the peritoneal cavity have been scattered and the results are varied. In 80 rats, body weight of 130 gm to 150 gm, sterile pure barium, sterile commercial barium, intestinal content, and mixed pure barium and intestinal content were experimentally injected into the peritoneal cavity. Consecutive weekly laparotomy and microscopic examination were done for 4 weeks. The results are as followings: 1. Mind inflammatory reaction and mild adhesion after sterile pure barium injection. 2. Mild inflammatory reaction and moderate adhesion after sterile commercial barium injection. 3. Acute peritonitis and abscess formation after intestinal content injection. 4. High mortality due to severe acute peritonitis, and severe adhesion in survivors after injection of both pure barium and intestinal content.

  11. Internally mixed soot, sulfates, and organic matter in aerosol particles from Mexico City

    Science.gov (United States)

    Adachi, K.; Buseck, P. R.

    2008-05-01

    Soot particles are major aerosol constituents that result from emissions of burning of fossil fuel and biomass. Because they both absorb sunlight and contribute to cloud formation, they are an influence on climate on local, regional, and global scales. It is therefore important to evaluate their optical and hygroscopic properties and those effects on the radiation budget. Those properties commonly change through reaction with other particles or gases, resulting in complex internal mixtures. Using transmission electron microscopy, we measured ~8000 particles (25 samples) with aerodynamic diameters from 0.05 to 0.3 μm that were collected in March 2006 from aircraft over Mexico City (MC) and adjacent areas. More than 50% of the particles consist of internally mixed soot, organic matter, and sulfate. Imaging combined with chemical analysis of individual particles show that many are coated, consist of aggregates, or both. Coatings on soot particles can amplify their light absorption, and coagulation with sulfates changes their hygroscopic properties, resulting in shorter lifetime. Our results suggest that a mixture of materials from multiple sources such as vehicles, power plants, and biomass burning occurs in individual particles, thereby increasing their complexity. Through changes in their optical and hygroscopic properties, internally mixed soot particles have a greater effect on the regional climate than uncoated soot particles. Moreover, soot occurs in more than 60% of all particles in the MC plumes, suggesting its important role in the formation of secondary aerosol particles.

  12. Internally mixed soot, sulfates, and organic matter in aerosol particles from Mexico City

    Directory of Open Access Journals (Sweden)

    K. Adachi

    2008-05-01

    Full Text Available Soot particles are major aerosol constituents that result from emissions of burning of fossil fuel and biomass. Because they both absorb sunlight and contribute to cloud formation, they are an influence on climate on local, regional, and global scales. It is therefore important to evaluate their optical and hygroscopic properties and those effects on the radiation budget. Those properties commonly change through reaction with other particles or gases, resulting in complex internal mixtures. Using transmission electron microscopy, we measured ~8000 particles (25 samples with aerodynamic diameters from 0.05 to 0.3 μm that were collected in March 2006 from aircraft over Mexico City (MC and adjacent areas. More than 50% of the particles consist of internally mixed soot, organic matter, and sulfate. Imaging combined with chemical analysis of individual particles show that many are coated, consist of aggregates, or both. Coatings on soot particles can amplify their light absorption, and coagulation with sulfates changes their hygroscopic properties, resulting in shorter lifetime. Our results suggest that a mixture of materials from multiple sources such as vehicles, power plants, and biomass burning occurs in individual particles, thereby increasing their complexity. Through changes in their optical and hygroscopic properties, internally mixed soot particles have a greater effect on the regional climate than uncoated soot particles. Moreover, soot occurs in more than 60% of all particles in the MC plumes, suggesting its important role in the formation of secondary aerosol particles.

  13. Effect of sulfate and carbonate minerals on particle-size distributions in arid soils

    Science.gov (United States)

    Goossens, Dirk; Buck, Brenda J.; Teng, Yuazxin; Robins, Colin; Goldstein, Harland L.

    2014-01-01

    Arid soils pose unique problems during measurement and interpretation of particle-size distributions (PSDs) because they often contain high concentrations of water-soluble salts. This study investigates the effects of sulfate and carbonate minerals on grain-size analysis by comparing analyses in water, in which the minerals dissolve, and isopropanol (IPA), in which they do not. The presence of gypsum, in particular, substantially affects particle-size analysis once the concentration of gypsum in the sample exceeds the mineral’s solubility threshold. For smaller concentrations particle-size results are unaffected. This is because at concentrations above the solubility threshold fine particles cement together or bind to coarser particles or aggregates already present in the sample, or soluble mineral coatings enlarge grains. Formation of discrete crystallites exacerbates the problem. When soluble minerals are dissolved the original, insoluble grains will become partly or entirely liberated. Thus, removing soluble minerals will result in an increase in measured fine particles. Distortion of particle-size analysis is larger for sulfate minerals than for carbonate minerals because of the much higher solubility in water of the former. When possible, arid soils should be analyzed using a liquid in which the mineral grains do not dissolve, such as IPA, because the results will more accurately reflect the PSD under most arid soil field conditions. This is especially important when interpreting soil and environmental processes affected by particle size.

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

    International Nuclear Information System (INIS)

    Full text: 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.

  15. Barium aluminate cement: its application

    International Nuclear Information System (INIS)

    The technology of manufacturing barium aluminate cement from barium sulfate and alumina, using a rotary kiln for firing the clinker is described. The method of granulation of the homogenized charge was used. Conditions of using the ''to mud'' method in industry were indicated. The physical and chemical properties of barium aluminate cement are determined and the quality of several batches of cement prepared on a semi-industrial scale and their suitability for making highly refractory concretes are tested. The optimal composition of the concretes is determined as a function of the mixing water and barium aluminate cement contents. Several experimental batches of concretes were used in the linings of furnaces in the steel industry. The suitability of these cements for use in fields other than steelmaking is examined. It is established that calcium aluminate cement has certain limited applications

  16. Beta-delayed particle emission from neutron-deficient tellurium, iodine, xenon, cesium and barium isotopes

    International Nuclear Information System (INIS)

    Using 58Ni, 63Cu(58Ni, xp yn) reactions and on-line mass separation the β-delayed proton and α-particle emission from neutron-deficient isotopes with 52113Xe, (protons), 114Cs (protons and α-particles) and 117Ba (protons). Coincidences between positons and β-delayed protons were recorded for 113Xe and 114Cs, yielding Qsub(EC)-Ssub(p) values of 7.92(15) and 8.73(15) MeV, respectively. The results are discussed within the statistical model. (orig.)

  17. Suppression in droplet growth kinetics by the addition of organics to sulfate particles

    Science.gov (United States)

    Wong, Jenny P. S.; Liggio, John; Li, Shao-Meng; Nenes, Athanasios; Abbatt, Jonathan P. D.

    2014-11-01

    Aerosol-cloud interactions are affected by the rate at which water vapor condenses onto particles during cloud droplet growth. Changes in droplet growth rates can impact cloud droplet number and size distribution. The current study investigated droplet growth kinetics of acidic and neutral sulfate particles which contained various amounts and types of organic compounds, from model compounds (carbonyls) to complex mixtures (α-pinene secondary organic aerosol and diesel engine exhaust). In most cases, the formed droplet size distributions were shifted to smaller sizes relative to control experiments (pure sulfate particles), due to suppression in droplet growth rates in the cloud condensation nuclei counter. The shift to smaller droplets correlated with increasing amounts of organic material, with the largest effect observed for acidic seed particles at low relative humidity. For all organics incorporated onto acidic particles, formation of high molecular weight compounds was observed, probably by acid-catalyzed Aldol condensation reactions in the case of carbonyls. To test the reversibility of this process, carbonyl experiments were conducted with acidic particles exposed to higher relative humidity. High molecular weight compounds were not measured in this case and no shift in droplet sizes was observed, suggesting that high molecular weight compounds are the species affecting the rate of water uptake. While these results provide laboratory evidence that organic compounds can slow droplet growth rates, the modeled mass accommodation coefficient of water on these particles (α > 0.1) indicates that this effect is unlikely to significantly affect cloud properties, consistent with infrequent field observations of slower droplet growth rates.

  18. Sulfated fucan from marine alga inhibits HeLa cells infection by HTLV-1 free particles: semi-quantitative analysis

    Directory of Open Access Journals (Sweden)

    Maria T. V. Romanos

    2011-04-01

    Full Text Available A sulfated fucan from Laminaria abyssalis marine alga prevented the interaction of HTLV-1 particles, purified from the MT-2 cell line, with HeLa cells. The infection obtained using a concentrated virus suspension was detected only by amplification of the newly synthesized HTLV-1 proviral cDNA by the nested-polymerase chain reaction (PCR. The sulfated polysaccharide was not toxic to the cells at a concentration of 100 µg/mL and prevented infection by the viral particles when added to the cell monolayers. The proviral cDNA was only detected when the sulfated polysaccharide was added to the cells three hours post-infection, indicating that the inhibitory activity occurred in the initial stages of virus-cell interaction. Our results demonstrate, for the first time, the ability of a sulfated fucan from marine algae to inhibit virus transmission through free virus particles.

  19. Surface reaction characteristics at low temperature synthesis BaTiO 3 particles by barium hydroxide aqueous solution and titanium tetraisopropoxide

    Science.gov (United States)

    Zeng, Min

    2011-05-01

    Well-crystallized cubic phase BaTiO 3 particles were prepared by heating the mixture of barium hydroxide aqueous solution and titania derived from the hydrolysis of titanium isopropoxide (TTIP) at 328 K, 348 K or 368 K for 24 h. The morphology and size of obtained particles depended on the reaction temperature and the Ba(OH) 2/TTIP molar ratio. By the direct hydrolytic reaction of titanium tetraisopropoxide, the high surface area titania (TiO 2) was obtained. The surface adsorption characteristics of the titania particles had been studied with different electric charges OH - ions or H + ions. The formation mechanism and kinetics of BaTiO 3 were examined by measuring the concentration of [Ba 2+] ions in the solution during the heating process. The experimental results showed that the heterogeneous nucleation of BaTiO 3 occurred on the titania surface, according to the Avrami's equation.

  20. Surface modification to produce hydrophobic nano-silica particles using sodium dodecyl sulfate as a modifier

    Science.gov (United States)

    Qiao, Bing; Liang, Yong; Wang, Ting-Jie; Jiang, Yanping

    2016-02-01

    Hydrophobic silica particles were prepared using the surfactant sodium dodecyl sulfate (SDS) as a modifier by a new route comprising three processes, namely, aqueous mixing, spray drying and thermal treatment. Since SDS dissolves in water, this route is free of an organic solvent and gave a perfect dispersion of SDS, that is, there was excellent contact between SDS and silica particles in the modification reaction. The hydrophobicity of the modified surface was verified by the contact angle of the nano-sized silica particles, which was 107°. The SDS grafting density reached 1.82 nm-2, which is near the highest value in the literature. The optimal parameters of the SDS/SiO2 ratio in the aqueous phase, process temperature and time of thermal treatment were determined to be 20%, 200 °C and 30 min, respectively. The grafting mechanism was studied by comparing the modification with that on same sized TiO2 particles, which indicated that the protons of the Brønsted acid sites on the surface of SiO2 reacted with SDS to give a carbocation which then formed a Si-O-C structure. This work showed that the hydrophilic surface of silica can be modified to be a hydrophobic surface by using a water soluble modifier SDS in a new modification route.

  1. Impact of organic coating on growth of ammonium sulfate particles: light extinction measurements relevant for the direct effect

    Science.gov (United States)

    Robinson, C. B.; Zarzana, K. J.; Hasenkopf, C. A.; Tolbert, M. A.

    2012-12-01

    Light extinction by particles is strongly dependent on chemical composition, particle size, and water uptake. Relative humidity affects extinction by causing changes in refractive index and particle size due to hygroscopic growth. The ability of particles to take up water depends on their composition and structure. In both laboratory and field studies, inorganic salts completely covered by an organic coating have been observed. The impact of this coating on water uptake is uncertain, and a systematic study that examines water uptake as a function of relative humidity is highly desirable. These data are critical to evaluate the aerosol direct effect on climate, which is one of the most uncertain aspects of future climate change. In this study, we probe the connection between aerosol composition, size and light extinction directly by measuring fRHext, the ratio of the extinction coefficient for humidified particles to the extinction coefficient for dry particles. Particles were composed of 1,2,6-hexanetriol and ammonium sulfate, a system that forms organic coatings around the inorganic core. A cavity ring-down aerosol extinction spectrometer at 532 nm is used to measure the optical growth factor as a function of relative humidity. The fRHext values for a range of %RH for pure ammonium sulfate, pure 1,2,6-hexanetriol, and ammonium sulfate particles with 1,2,6-hexanetriol coatings were measured. The coated particles are created using a method of liquid-liquid separation, where the particles are exposed to water vapor creating a RH% above their deliquescence RH%. The particles are then dried with a Nafion dryer to a RH% that is below the point where liquid-liquid phase separation is observed, but above the efflorescence RH%. Pure 1,2,6-hexanetriol takes up little water over the observed RH range of 45-65%, and therefore fRHext ~ 1. With pure ammonium sulfate for the same RH% range, the fRHext varied from 1.5 - 2, depending on the RH% and the particle size. For the

  2. Cloud droplet activation of mixed organic-sulfate particles produced by the photooxidation of isoprene

    Directory of Open Access Journals (Sweden)

    S. M. King

    2010-04-01

    Full Text Available The cloud condensation nuclei (CCN properties of ammonium sulfate particles mixed with organic material condensed during the hydroxyl-radical-initiated photooxidation of isoprene (C5H8 were investigated in the continuous-flow Harvard Environmental Chamber. CCN activation curves were measured for organic particle mass concentrations of 0.5 to 10.0 μg m−3, NOx concentrations from under 0.4 ppbv up to 38 ppbv, particle mobility diameters from 70 to 150 nm, and thermodenuder temperatures from 25 to 100 °C. At 25 °C, the observed CCN activation curves were accurately described by a Köhler model having two internally mixed components, namely ammonium sulfate and secondary organic material. The modeled physicochemical parameters of the organic material were equivalent to an effective hygroscopicity parameter κORG of 0.10±0.03, regardless of the C5H8:NOx concentration ratio for the span of >200:0.4 to 50:38 (ppbv:ppbv. The volatilization curves (i.e., plots of the residual organic volume fraction against temperature were also similar for the span of investigated C5H8:NOx ratios, suggesting a broad similarity of particle chemical composition. This suggestion was supported by limited variance at 25 °C among the particle mass spectra. For example, the signal intensity at m/z 44 (which can result from the fragmentation of oxidized molecules believed to affect hygroscopicity and CCN properties varied weakly from 6 to 9% across the range of investigated conditions. In contradistinction to the results for 25 °C, conditioning up to 100 °C in the thermodenuder significantly reduced CCN activity. The altered CCN activity might be explained by chemical reactions (e.g., decomposition or oligomerization of the secondary organic material at elevated temperatures. The study's results at 25 °C, in conjunction with the results of

  3. Radioactive Barium Ion Trap Based on Metal-Organic Framework for Efficient and Irreversible Removal of Barium from Nuclear Wastewater.

    Science.gov (United States)

    Peng, Yaguang; Huang, Hongliang; Liu, Dahuan; Zhong, Chongli

    2016-04-01

    Highly efficient and irreversible capture of radioactive barium from aqueous media remains a serious task for nuclear waste disposal and environmental protection. To address this task, here we propose a concept of barium ion trap based on metal-organic framework (MOF) with a strong barium-chelating group (sulfate and sulfonic acid group) in the pore structures of MOFs. The functionalized MOF-based ion traps can remove >90% of the barium within the first 5 min, and the removal efficiency reaches 99% after equilibrium. Remarkably, the sulfate-group-functionalized ion trap demonstrates a high barium uptake capacity of 131.1 mg g(-1), which surpasses most of the reported sorbents and can selectively capture barium from nuclear wastewater, whereas the sulfonic-acid-group-functionalized ion trap exhibits ultrafast kinetics with a kinetic rate constant k2 of 27.77 g mg(-1) min(-1), which is 1-3 orders of magnitude higher than existing sorbents. Both of the two MOF-based ion traps can capture barium irreversibly. Our work proposes a new strategy to design barium adsorbent materials and provides a new perspective for removing radioactive barium and other radionuclides from nuclear wastewater for environment remediation. Besides, the concrete mechanisms of barium-sorbent interactions are also demonstrated in this contribution. PMID:26999358

  4. Medical radiation shielding effect by composition of barium compounds

    International Nuclear Information System (INIS)

    Highlight: ► Radiation shielding sheet was manufactured using BaSO4 and a combination of tourmaline, tungsten, silicon and rubber polymer. ► The particle packing of barium tends to be related to the tensile strength. ► The tensile strength was most excellent in the sheets containing rubber. ► The shielding ability of the tungsten and silicon combination with BaSO4 was the same as that of a 0.3 mm lead equivalent. - Abstract: Shielding aprons were manufactured from barium sulfate as a potential substitute for the lead aprons used most commonly for medical radiation shielding. Six types of radiation shielding sheets made from a combination of tungsten, molybdenum, rubber and silicon with a barium sulfate base were manufactured, and their transmission doses were compared with those of a lead standard. In the process of producing the radiation shielding sheets, the particle packing and porosity of the materials, appropriate weight-average molecular weight to number-average molecular weight ratio and tensile strength were investigated to determine the optimal mixing process. The transmission dose was measured by applying a lead equivalent test method () of X-ray protective supplies in the Korea Industrial Standard. The transmission doses of the lead standard with a thickness of 0.05, 0.1, 0.15, 0.2, 0.25, 0.3 and 0.35 mm, as well as the six types of radiation shielding sheet were obtained at a tube voltage of 50, 80, 100, 120 and 150 kVp. According to the results, the combination of barium, tungsten, molybdenum and silicon recorded a dose of a 0.3 mm lead equivalent and its particle packing and porosity were 28–36% and 12–22%, respectively. Nevertheless, satisfactory shielding ability could be obtained with a porosity >20% and particle packing of 30%. Therefore, it is a potential replacement for lead sheet and can be considered a proper medical radiation shielding sheet with good economic feasibility.

  5. The enhancement of photoluminescence characteristics of Eu-doped barium strontium silicate phosphor particles by co-doping materials

    International Nuclear Information System (INIS)

    Green light emitting (Ba,Sr)2SiO4:Eu phosphor particles with high photoluminescence intensity under long wavelength ultraviolet (UV) were prepared by spray pyrolysis from colloidal spray solution. Yttrium, cerium and holmium components were introduced as co-doping materials to improve the photoluminescence characteristics of (Ba,Sr)2SiO4:Eu phosphor particles in the spray pyrolysis. The photoluminescence intensities of co-doped (Ba,Sr)2SiO4:Eu phosphor particles were about 120∼143% of (Ba,Sr)2SiO4:Eu phosphor particles without co-dopant. The highest photoluminescence intensity was achieved when the doping concentration of yttrium was about 1.7 times of the doping concentration of europium. The photoluminescence intensity of the sieved phosphor particles using 20 μm sieve was comparable to that of the original (Ba,Sr)2SiO4:Eu phosphor particles

  6. Quantitative Analysis of Sulfate in Water by Indirect EDTA Titration

    Science.gov (United States)

    Belle-Oudry, Deirdre

    2008-01-01

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

  7. Barium enema (image)

    Science.gov (United States)

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

  8. Liquid-liquid phase separation and morphology of internally mixed dicarboxylic acids/ammonium sulfate/water particles

    OpenAIRE

    Song, M.; Marcolli, C.; U. K. Krieger; A. Zuend; Peter, T

    2012-01-01

    Knowledge of the physical state and morphology of internally mixed organic/inorganic aerosol particles is still largely uncertain. To obtain more detailed information on liquid-liquid phase separation (LLPS) and morphology of the particles, we investigated complex mixtures of atmospherically relevant dicarboxylic acids containing 5–7 carbon atoms (C5, C6 and C7) having oxygen-to-carbon atomic ratios (O:C) of 0.80, 0.67, and 0.57, respectively, mixed with ammonium sulfate (AS). With mi...

  9. Doped barium titanate nanoparticles

    Indian Academy of Sciences (India)

    T K Kundu; A Jana; P Barik

    2008-06-01

    We have synthesized nickel (Ni) and iron (Fe) ion doped BaTiO3 nanoparticles through a chemical route using polyvinyl alcohol (PVA). The concentration of dopant varies from 0 to 2 mole% in the specimens. The results from X-ray diffractograms and transmission electron micrographs show that the particle diameters in the specimen lie in the range 24–40 nm. It is seen that the dielectric permittivity in doped specimens is enhanced by an order of magnitude compared to undoped barium titanate ceramics. The dielectric permittivity shows maxima at 0.3 mole% doping of Fe ion and 0.6 mole% of Ni ion. The unusual dielectric behaviour of the specimens is explained in terms of the change in crystalline structure of the specimens.

  10. Effects of the physical state of tropospheric ammonium-sulfate-nitrate particles on global aerosol direct radiative forcing

    Directory of Open Access Journals (Sweden)

    S. T. Martin

    2004-01-01

    Full Text Available The effect of aqueous versus crystalline sulfate-nitrate-ammonium tropospheric particles on global aerosol direct radiative forcing is assessed. A global three-dimensional chemical transport model predicts sulfate, nitrate, and ammonium aerosol mass. An aerosol thermodynamics model is called twice, once for the upper side (US and once for lower side (LS of the hysteresis loop of particle phase. On the LS, the sulfate mass budget is 40% solid ammonium sulfate, 12% letovicite, 11% ammonium bisulfate, and 37% aqueous. The LS nitrate mass budget is 26% solid ammonium nitrate, 7% aqueous, and 67% gas-phase nitric acid release due to increased volatility upon crystallization. The LS ammonium budget is 45% solid ammonium sulfate, 10% letovicite, 6% ammonium bisulfate, 4% ammonium nitrate, 7% ammonia release due to increased volatility, and 28% aqueous. LS aerosol water mass partitions as 22% effloresced to the gas-phase and 78% remaining as aerosol mass. The predicted US/LS global fields of aerosol mass are employed in a Mie scattering model to generate global US/LS aerosol optical properties, including scattering efficiency, single scattering albedo, and asymmetry parameter. Global annual average LS optical depth and mass scattering efficiency are, respectively, 0.023 and 10.7 m2 (g SO4-2-1, which compare to US values of 0.030 and 13.9 m2 (g SO4-2-1. Radiative transport is computed, first for a base case having no aerosol and then for the two global fields corresponding to the US and LS of the hysteresis loop. Regional, global, seasonal, and annual averages of top-of-the-atmosphere aerosol radiative forcing on the LS and US (FL and FU, respectively, in W m-2 are calculated. Including both anthropogenic and natural emissions, we obtain global annual averages of FL=-0.750, FU=-0.930, and DFU,L=24% for full sky calculations without clouds and FL=-0.485, FU=-0.605, and DFU,L=25% when clouds are included. Regionally, DFU,L=48% over the USA, 55% over Europe

  11. Synthesis and magnetic properties of barium-calcium hexaferrite particles prepared by sol-gel and microemulsion techniques

    Science.gov (United States)

    Jotania, R. B.; Khomane, R. B.; Chauhan, C. C.; Menon, S. K.; Kulkarni, B. D.

    The preparation of W-type hexaferrite particles with the composition BaCa 2Fe 16O 27 by microemulsion and a stearic acid sol-gel method with and without surfactant has been investigated at various sintering temperatures. The structural and magnetic characteristics have been studied by X-ray diffraction (XRD), a vibrating sample magnetometer (VSM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetric (DSC) and Fourier transform infrared (FTIR) techniques. The effect of sintering temperature on the properties of BaCa 2Fe 16O 27 hexaferrites has been studied. The value of saturation magnetization ( Ms) depends on types of surfactant used. The sample prepared in the presence of polyoxyethylene (20) sorbitan monooleat (Tween 80) shows low saturation magnetization ( Ms=15.10 emu/g), whereas the other sample prepared in the presence of a surfactant cetyltrimethylammonium bromide (CTAB) exhibits high saturation magnetization ( Ms=24.60 emu/g) compared to the normal sample.

  12. Radioisotope analyzer of barium

    International Nuclear Information System (INIS)

    Principle of operation and construction of radioisotope barium sulphate analyzer type MZB-2 for fast determination of barium sulphate content in barite ores and enrichment products are described. The gauge equipped with Am-241 and a scintillation detector enables measurement of barium sulphate content in prepared samples of barite ores in the range 60% - 100% with the accuracy of 1%. The gauge is used in laboratories of barite mine and ore processing plant. 2 refs., 2 figs., 1 tab. (author)

  13. Synthesis and magnetic properties of barium-calcium hexaferrite particles prepared by sol-gel and microemulsion techniques

    Energy Technology Data Exchange (ETDEWEB)

    Jotania, R.B. [Department of Physics, Gujarat University, Ahmedabad 380 009, Gujarat (India)], E-mail: rbjotania@gmail.com; Khomane, R.B. [Chemical Engineering Division, National Chemical Laboratory, Pune 411008, Maharastra (India); Chauhan, C.C. [Department of Physics, Gujarat University, Ahmedabad 380 009, Gujarat (India); Menon, S.K. [Department of Chemistry, Gujarat University, Ahmedabad 380 009, Gujarat (India); Kulkarni, B.D. [Chemical Engineering Division, National Chemical Laboratory, Pune 411008, Maharastra (India)

    2008-03-15

    The preparation of W-type hexaferrite particles with the composition BaCa{sub 2}Fe{sub 16}O{sub 27} by microemulsion and a stearic acid sol-gel method with and without surfactant has been investigated at various sintering temperatures. The structural and magnetic characteristics have been studied by X-ray diffraction (XRD), a vibrating sample magnetometer (VSM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetric (DSC) and Fourier transform infrared (FTIR) techniques. The effect of sintering temperature on the properties of BaCa{sub 2}Fe{sub 16}O{sub 27} hexaferrites has been studied. The value of saturation magnetization (M{sub s}) depends on types of surfactant used. The sample prepared in the presence of polyoxyethylene (20) sorbitan monooleat (Tween 80) shows low saturation magnetization (M{sub s}=15.10 emu/g), whereas the other sample prepared in the presence of a surfactant cetyltrimethylammonium bromide (CTAB) exhibits high saturation magnetization (M{sub s}=24.60 emu/g) compared to the normal sample.

  14. Preparation of functional composite particles of salbutamol sulfate using a 4-fluid nozzle spray-drying technique.

    Science.gov (United States)

    Chen, Richer; Okamoto, Hirokazu; Danjo, Kazumi

    2008-03-01

    A previous study on spray-drying demonstrated that it could promote the solubility of poorly water-soluble drugs using water-soluble polymers. Here, the preparation of composite particles of salbutamol sulfate (Sb) with water-insoluble polymers, such as Eudragit RS (RS) or Eudragit RL (RL) as a carrier, was examined. Despite the water insolubility of both polymers, the permeability of water was low in the former but high in the latter. We attempted to prepare controlled release composite particles by exploiting the characteristics of these carriers. The composite particles of the three components (Sb, RS, and RL) were prepared using a 4-fluid nozzle spray-dryer, and their physico-chemical and dissolution properties were compared with physical mixtures. Examination of particle morphology by scanning electron microscopy (SEM) revealed that the particles from the spray-drying process had atomized to several microns and were spherical. Analysis by X-ray diffraction and differential scanning calorimetry revealed that diffraction peaks and heat of fusion of Sb in the spray-dried samples decreased, indicating that the drug was amorphous and formed a solid dispersion. FT-IR analysis suggested that the amino group of Sb and a carbonyl group of the polymers formed a hydrogen bond. A dissolution test of Sb-RS-RL particles prepared using the 4-fluid nozzle spray-drying method showed that release rates were depressed significantly compared to the physical mixture at pH 1.2 and 6.8, and the depression was greater when RS was used instead of RL, presumably because of the permeability difference. The compression of these particles into tablets revealed that desirable controlled released dosage forms could be prepared. In addition, Sb was used to simulate an anti-asthmatic drug. For this an Andersen cascade impactor for dry powder inhalers was used to investigate delivery to the lungs. PMID:18310932

  15. Mortality Risk Associated with Short-Term Exposure to Traffic Particles and Sulfates

    OpenAIRE

    Maynard, Dan; Gryparis, Alexandros; Coull, Brent Andrew; Schwartz, Joel David

    2007-01-01

    Background: Many studies have shown that airborne particles are associated with increased risk of death, but attention has more recently focused on the differential toxicity of particles from different sources. Geographic information system (GIS) approaches have recently been used to improve exposure assessment, particularly for traffic particles, but only for long-term exposure. Objectives: We analyzed approximately 100,000 deaths from all, cardiovascular, and respiratory causes for the year...

  16. Acidic gases and nitrate and sulfate particles in the atmosphere in the city of Guadalajara, México.

    Science.gov (United States)

    Saldarriaga-Noreña, Hugo; Waliszewski, Stefan; Murillo-Tovar, Mario; Hernández-Mena, Leonel; de la Garza-Rodríguez, Iliana; Colunga-Urbina, Edith; Cuevas-Ordaz, Rosalva

    2012-05-01

    Atmospheric concentrations of nitrous acid, nitric acid, nitrate and sulfate particles were obtained in this study from April to June 2008 in the center of the city of Guadalajara, while concentrations of ozone, sulfur dioxide, nitrogen dioxide and meteorological parameters (temperature and relative humidity), were acquired by the Secretaría del Medio Ambiente para el Desarrollo Sustentable del Estado de Jalisco (SEMADES). The results showed that nitric acid (2.7 μg m(-3)) was 2.7 times higher than nitrous acid (1.0 μg m(-3)). The sulfur dioxide (SO(2)) concentration indicated an opposite trend to sulfate (SO(4) (2-)), with the average concentration of SO(2) (6.9 μg m(-3)) higher in almost the entire period of study. The sulfur conversion ratio (Fs, 24.9%) and nitrogen conversion ratio (Fn, 6.2%), were revealed to be similar to that reported in other urban areas during warm seasons. It is also noted that ozone is not the main oxidizer of nitrogen dioxide and sulfur dioxide. This determination was made by taking into account the slightly positively correlation determined for Fn (r(2) = 0.084) and Fs (r(2) = 0.092) with ozone that perhaps suggests there are other oxidizing species such as the radical OH, which are playing an important role in the processes of atmospheric oxidation in this area. PMID:22358115

  17. The high-temperature sulphation behavior of barium-based sorbents during coal combustion

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, J.; Li, N.; Zhou, J.; Cao, X.; Liu, J.; Zhao, X.; Cen, K.

    2000-07-01

    In order to promote the sulfur removal efficiency during coal combustion, the high-temperature sulfation behavior of barium-based sorbents was studied. The sulfation product BaSO{sub 4} which did not decompose until 1,580 C had much better thermal stability than CaSO{sub 4} which rapidly decomposed at about 1,300 C. The desulfurization effect of barium salt Ba{sup 2+} was much better than calcium salt Ca{sup 2+} during coal combustion at about 1,200{approximately}1,300 C. The sulfur removal efficiency of barium-based sorbents could achieve 35.5% in industrial grate furnace.

  18. On the regulation of climate: a sulfate particle feedback loop involving deep convection

    International Nuclear Information System (INIS)

    The authors propose a climate stabilizing feedback loop involving biogenic sulfur. The mechanism is similar to the CLAW hypothesis (Charlson et al., 1987) but does not require the active participation of the ocean biota. The magnitude of the feedback response in this loop is derived by convective transport of biogenic sulfur over tropical oceans into the middle and high troposphere. Once aloft, the sulfur is oxidized into low-volatile species which nucleate new particles that later subside back into the subtropical marine boundary layer (MBL) and serve as cloud condensation nuclei (CCN). The MBL clouds are susceptible to albedo modification by changes in CCN concentrations (Platnick and Twomey, 1995). The authors envision that as global temperatures rise the sea surface warms, convective mass transport of sulfur will rise and the increased mass of sulfur in the upper troposphere will lead to higher numbers of particles or a shift in the particle size distribution to larger sizes. In either case, there is an increase in the number of particles large enough to act as CCN in the air subsiding back into the MBL. The increase in CCN increases the cloud albedo, decreases the solar input to the surface and the temperature decreases. More measurements are needed to confirm whether the magnitude of increased sulfur carried through the loop as a function of increased sea surface temperature is sufficient to close the loop and regulate the climate. 45 refs., 1 fig

  19. Tailored Barium Swallow Study

    Science.gov (United States)

    ... View Denver Pollen Count You are here: Programs & Services > Tests We Offer > Imaging Tests Tailored Barium Swallow Study The TBS is a special study that is completed in radiology. The test evaluates the mouth and the throat ...

  20. Liquid-liquid phase separation and morphology of internally mixed dicarboxylic acids/ammonium sulfate/water particles

    Directory of Open Access Journals (Sweden)

    M. Song

    2012-03-01

    Full Text Available Knowledge of the physical state and morphology of internally mixed organic/inorganic aerosol particles is still largely uncertain. To obtain more detailed information on liquid-liquid phase separation (LLPS and morphology of the particles, we investigated complex mixtures of atmospherically relevant dicarboxylic acids containing 5, 6, and 7 carbon atoms (C5, C6 and C7 having oxygen-to-carbon atomic ratios (O:C of 0.80, 0.67, and 0.57, respectively, mixed with ammonium sulfate (AS. With micrometer-sized particles of C5/AS/H2O, C6/AS/H2O and C7/AS/H2O as model systems deposited on a hydrophobically coated substrate, laboratory experiments were conducted for various organic-to-inorganic dry mass ratios (OIR using optical microscopy and Raman spectroscopy. When exposed to cycles of relative humidity (RH, each system showed significantly different phase transitions. While the C5/AS/H2O particles showed no LLPS with OIR = 2:1, 1:1 and 1:4 down to 20% RH, the C6/AS/H2O and C7/AS/H2O particles exhibit LLPS upon drying at RH 50 to 85% and ~90%, respectively, via spinodal decomposition, growth of a second phase from the particle surface or nucleation-and-growth mechanisms depending on the OIR. This suggests that LLPS commonly occurs within the range of O:C < 0.7 in tropospheric organic/inorganic aerosols. To support the comparison and interpretation of the experimentally observed phase transitions, thermodynamic equilibrium calculations were performed with the AIOMFAC model. For the C7/AS/H2O and C6/AS/H2O systems, the calculated phase diagrams agree well with the observations while for the C5/AS/H2O system LLPS is predicted by the model at RH below 60% and higher AS concentration, but was not observed in the experiments. Both core-shell structures and partially engulfed structures were observed for the investigated particles, suggesting that such

  1. Liquid-liquid phase separation and morphology of internally mixed dicarboxylic acids/ammonium sulfate/water particles

    Directory of Open Access Journals (Sweden)

    M. Song

    2011-10-01

    Full Text Available Knowledge of the physical state and morphology of internally mixed organic/inorganic aerosol particles is still largely uncertain. To obtain more detailed information on liquid-liquid phase separation (LLPS and morphology of the particles, we investigated complex mixtures of atmospherically relevant dicarboxylic acids containing 5–7 carbon atoms (C5, C6 and C7 having oxygen-to-carbon atomic ratios (O:C of 0.80, 0.67, and 0.57, respectively, mixed with ammonium sulfate (AS. With micrometer-sized particles of C5/AS/H2O, C6/AS/H2O and C7/AS/H2O as model systems deposited on a hydrophobically coated substrate, laboratory experiments were conducted for various organic-to-inorganic dry mass ratios (OIR using optical microscopy and Raman spectroscopy. When exposed to cycles of relative humidity (RH, each system showed significantly different phase transitions. While the C5/AS/H2O particles showed no LLPS with OIR = 2:1, 1:1 and 1:4 down to 20% RH, the C6/AS/H2O and C7/AS/H2O particles exhibit LLPS upon drying at RH 50% to 85% and ~90%, respectively, via spinodal decomposition, growth of a second phase from the particle surface or nucleation-and-growth mechanisms depending on the OIR. This suggests that LLPS commonly occurs within the range of O:C<0.7 in tropospheric organic-inorganic aerosols. To support the comparison and interpretation of the experimentally observed phase transitions, thermodynamic equilibrium calculations were performed with the AIOMFAC model. For the C7/AS/H2O and C6/AS/H2O systems, the calculated phase diagrams agree well with the observations while for the C5/AS/H2O system LLPS is predicted by the model at RH below 60% and higher AS concentration, but was not observed in the experiments. Both core-shell structures and partially engulfed structures were observed for the investigated particles, suggesting that such morphologies

  2. Effects of particle size and acid addition on the remediation of chromite ore processing residue using ferrous sulfate.

    Science.gov (United States)

    Jagupilla, Santhi Chandra; Moon, Deok Hyun; Wazne, Mahmoud; Christodoulatos, Christos; Kim, Min Gyu

    2009-08-30

    A bench-scale treatability study was conducted to assess the effects of particle size and acid addition on the remediation of chromite ore processing residue (COPR) using ferrous sulfate. The remediation scheme entailed the chemical reduction of hexavalent chromium [Cr(VI)] and the mitigation of swell potential. Leaching tests and the EQ3/6 geochemical model were used to estimate the acid dosage required to destabilize Cr(VI)-bearing and swell-causing minerals. The model predicted greater acid dosage than that estimated from the batch leaching tests. This indicated that mass transfer limitation may be playing a significant role in impeding the dissolution of COPR minerals following acid addition and hence hindering the remediation of COPR. Cr(VI) concentrations determined by alkaline digestion for the treated samples were less than the current NJDEP standard. However, Cr(VI) concentrations measured by X-ray absorption near edge structure (XANES) were greater than those measured by alkaline digestion. Greater Cr(VI) percentages were reduced for acid pretreated and also for smaller particle size COPR samples. Upon treatment, brownmillerite content was greatly reduced for the acid pretreated samples. Conversely, ettringite, a swell-causing mineral, was not observed in the treated COPR. PMID:19272700

  3. Infrared Turbidimetric Titration Method for Sulfate Ions in Brackish Water

    OpenAIRE

    Benabadji Nouredine; Kherici Samira; Benouali Djillali

    2012-01-01

    In this work an infrared turbidimetric titration method is described for the determination of sulfate ions in brackish water. A suspension of barium sulfate is produced in an aqueous solution and/or brackish water sample by the addition of barium chloride solution and the turbidity is monitored with the help of an immersed infrared sensor. The developed sensor utilizes an optical system to measure the evolution of turbidity during the titration. This sensor is a simple device designed in th...

  4. Formation of fine palladium particles from palladium sulfate aqueous solution by gamma-ray irradiation as observed by electronic absorption spectroscopy and dynamic light scattering

    International Nuclear Information System (INIS)

    To find a way of probing the coagulation of metal particles formed by the irradiation of metallic ion solution without surfactant, palladium sulfate aqueous solution was irradiated with gamma rays (11.2kGy/h, 10kGy) and turbidity change of the solution after irradiation was followed by optical density at 700nm using a UV-visible spectrophotometer. The particle diameter distribution was monitored by dynamic light scattering. The results indicate that the turbidity decreased monotonously, and that there are major peaks in the distributions, one with diameters in the 400-800nm region and the other with diameters in the 1500-2500nm. The density of the particles seems to be smaller than that of bulk palladium metal. Similar experiments were carried out on palladium-silver sulfate solution. (author)

  5. Lower GI Series (Barium Enema)

    Science.gov (United States)

    ... barium into a bedpan or nearby toilet. A health care professional may give you an enema to flush out the rest of the barium. An x-ray technician and a radiologist perform a lower gastrointestinal (GI) series at a ...

  6. Physicochemical characteristics, oxidative capacities and cytotoxicities of sulfate-coated, 1,4-NQ-coated and ozone-aged black carbon particles

    Science.gov (United States)

    Li, Qian; Shang, Jing; Liu, Jia; Xu, Weiwei; Feng, Xiang; Li, Rui; Zhu, Tong

    2015-02-01

    Black carbon (BC) particles play important roles in climate change, visibility impairment, atmospheric reaction process, and health effect. The aging processes of BC alter not only atmospheric composition, but also the physicochemical characteristics of BC itself, thus impacting the environment and health effects. Here, three types of BC including sulfate-coated, 1,4-naphthoquinone (1,4-NQ)-coated, and O3-aged BC are presented. The morphologies, structures, extraction components, the amount of water-soluble organic carbon (WSOC) and free radical intensities of the three types of BC particles are examined by transmission electron microscopy, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), ultraviolet-visible spectrophotometry, total organic carbon detector and electron paramagnetic resonance, respectively. Dithiothreitol (DTT) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide assays are utilized to assess the changes in oxidative capacity and cytotoxicity towards murine alveolar macrophage cells. The orders of DTT activities and cytotoxicities of the particles are both arranged as follows: BC/1,4-NQ > BC/O3 > BC > BC/sulfate, mainly because 1,4-NQ owned high oxidative potential and cytotoxicity, while sulfate did not exhibit oxidative capacity and cytotoxicity. The insoluble components of particles contribute most of the total DTT activity, whereas either water or methanol extract is minor contributor. DTT activity was positively correlated with both WSOC content and free radical intensity, with the correlation between DTT activity and WSOC content was stronger than that between DTT activity and free radical intensity.

  7. Observed Barium Emission Rates

    Science.gov (United States)

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

    1993-01-01

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

  8. Chondroitin sulfate

    Science.gov (United States)

    ... in combination with glucosamine sulfate, shark cartilage, and camphor. Some people also inject chondroitin sulfate into the ... in combination with glucosamine sulfate, shark cartilage, and camphor seems to reduce arthritis symptoms. However, any symptom ...

  9. Rare Isotope Insights into Supereruptions: Rare Sulfur and Triple Oxygen Isotope Geochemistry of Stratospheric Sulfate Aerosols Absorbed on Volcanic Ash Particles

    Science.gov (United States)

    Bindeman, I. N.; Eiler, J.; Wing, B.; Farquhar, J.

    2006-12-01

    We present analyses of stable isotopic ratios of 17O/16O, 18O/16O, 34S/32S, and 33S/32S, 36S/32S of sulfate leached from volcanic ash of a series of well-known volcanic eruptions. This list covers much of the diversity of sizes and the character of volcanic eruptions. Particular emphasis is paid to the Lava Creek Tuff of Yellowstone and we present wide geographic sample coverage for this unit. This global dataset spans a significant range in δ34S, δ18O, and Δ17O of sulfate (29, 30 and 3.3 permil respectively) with oxygen isotopes recording mass-independent fractionation and sulfur isotopes exhibiting mass-dependent behavior. These ranges are defined by the isotopic compositions of products of large caldera forming eruptions. Proximal ignimbrites and coarse ash typically do not contain sulfate. The presence of sulfate with Δ17O > 0.2 permil is characteristic of small distal ash particles, suggesting that sulfate aerosols were scavenged after they underwent atmospheric photochemical reactions. Additionally, sediments that embed ash layers either do not contain sulfate or contain minor sulfate with Δ17O near 0 permil, suggesting that the observed sulfate in ash is of volcanic origin. Mass-dependent sulfur isotopic compositions suggest that sulfate-forming reactions did not involve photolysis of SO2, unlike the situation inferred for some pre-2.3 Ga sulfates or hypothesized to occur during the formation of sulfate associated with plinian eruptions that pierce the ozone layer. However, sulfate in the products of caldera-forming eruptions display a large δ34S range and fractionation relationships that do not follow equilibrium slopes of 0.515 and 1.90 for 33S/32S vs. 34S/32S and 36S/32S vs. 34S/32S, respectively. This implies that the sulfur isotopic characteristics of these sulfates were not set by a single stage, high-temperature equilibrium process in the volcanic plum. The data presented here are consistent with a single stage kinetic fractionation of sulfur

  10. Experimental Design: Application to the Development of a Treatment to Inhibit the Deposition of Barium Sulfate Liable to Be Formed in Enhanced Oil Recovery by Waterflooding Planification d'expériences : application à la mise au point d'un traitement inhibiteur du depôt de sulfate de baryum susceptible de se former en récupération assistée du pétrole par injection d'eau

    Directory of Open Access Journals (Sweden)

    Roque C.

    2006-11-01

    Full Text Available For technical and economic reasons, waterflooding is the most widely-used method in enhanced oil recovery [1]. In many situations, unfortunately, the formation water is incompatible with the injection water. The deposits and corrosion induced by the various reactions of this incompatibility cause irreversible damage, which is especially dangerous for the reservoir rock and the downhole and surface production facilities. This study is concerned exclusively with barium sulfate deposits liable to occur in surface production facilities by the mixing of injection water loaded with sulfate (1300 mg. 1 to the power of (-1 with a formation water with a high barium concentration (1200 mg. 1 to the power of (-1 [2]. Pour des raisons techniques et économiques, l'injection d'eau dans les réservoirs est la méthode la plus employée dans la récupération du pétrole. Malheureusement, dans bien des cas, l'eau en place dans le gisement est incompatible avec l'eau injectée. Les dépôts et les corrosions causés par les diverses réactions physico-chimiques de cette incompatibilité provoquent des dégradations irréversibles particulièrement dangereuses pour les installations de production de fond comme de surface et quelquefois pour la roche réservoir elle-même. Dans le cadre des travaux de recherche relatifs à l'inhibition des dépôts de sulfate sur le champ algérien de Tin Fouyé Tabankort, cette étude a eu pour objectif de sélectionner et d'adapter aux conditions spécifiques de la production un traitement de prévention des dépôts par injection d'un agent inhibiteur. Elle concerne exclusivement les dépôts de sulfate de baryum pouvant apparaître dans les installations de production par mélange d'eau d'injection très chargée en ion sulfate (1300 mg. 1 puissance(-1 avec une eau de gisement très concentrée en élément baryum (1200 mg. 1 puissance(-1. Une méthode expérimentale au laboratoire, faisant appel à des mesures de type

  11. New barium tantalum sulphides

    International Nuclear Information System (INIS)

    The authors discuss a new barium tantalum sulphide, Ba3Ta2S8, prepared by sulphurization of a mixture of BaCO3 and Ta2O5. The electron and powder X-ray diffraction patterns of the compound are indexed on the basis of a monoclinic cell with lattice constants. A structure model is proposed. The refinement based on the powder X-ray diffraction intensities is performed

  12. Barium calcium hydroxyapatite solid solutions

    International Nuclear Information System (INIS)

    The replacement of calcium by barium in the hydroxyapatite structure by solid-state reaction at different temperatures and by precipitation from an aqueous system has been investigated by X-ray diffraction and i.r. absorption analyses. The products obtained by solid-state reaction at 1200 deg C are solid solutions over the range of barium concentration 60 to 100 atom %. The lattice dimensions and the i.r. frequencies of the solid solutions vary linearly with the atom % of barium. Only small amounts of barium can be incorporated in hydroxyapatite by precipitation from the aqueous system. (author)

  13. Direct shortwave forcing of climate by anthropogenic sulfate aerosol: Sensitivity to particle size, composition, and relative humidity

    Energy Technology Data Exchange (ETDEWEB)

    Nemesure, S.; Wagener, R.; Schwartz, S.E. [Brookhaven National Lab., Upton, New York (United States)

    1996-04-01

    Recent estimates of global or hemispheric average forcing of climate by anthropogenic sulfate aerosol due to scattering of shortwave radiation are uncertain by more than a factor of 2. This paper examines the sensitivity of forcing to these microphysical properties for the purposes of obtaining a better understanding of the properties required to reduce the uncertainty in the forcing.

  14. Glucosamine sulfate

    Science.gov (United States)

    ... to control arthritis pain. These creams usually contain camphor and other ingredients in addition to glucosamine. Glucosamine ... in combination with chondroitin sulfate, shark cartilage, and camphor for up to 8 weeks. Glucosamine sulfate can ...

  15. Barium zirconate base ceramics

    International Nuclear Information System (INIS)

    The chemical corrosion at high temperatures is a serious problem in the refractory materials field, leading to degradation and bath contamination by elements of the refractory. The main objective of this work was to search for ceramics that could present higher resistance to chemical attack by aggressive molten oxides. The general behaviour of a ceramic material based on barium zirconate (Ba Zr O3) with the addition of different amounts of liquid phase former was investigated. The densification behaviour occurred during different heat treatments, as well as the microstructure development, as a function of the additives and their reactions with the main phase, were observed and are discussed. (author)

  16. Sulfation of CaO particles in a carbonation/calcination loop to capture CO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Grasa, G.S.; Alonso, M.; Abanades, J.C. [CSIC, Zaragoza (Spain)

    2008-03-15

    CaO is being proposed as a regenerable sorbent of CO{sub 2} via a carbonation/calcination loop. It is well known that natural sorbents lose their capacity to capture CO{sub 2} with the number of cycles due to textural degradation. In coal combustion systems, reaction with the SO{sub 2} present in flue gases also causes sorbent deactivation. This work investigates the effect of partial sorbent sulfation on the amount of CaO used in systems where both carbonation and sulfation reactions are competing. We have found that SO{sub 2} reacts with the deactivated CaO resulting from repetitive calcination/carbonation reactions. Therefore, the deactivation of CaO as a result of the presence of SO{sub 2} is lower than one would expect if one assumes that SO{sub 2} reacts only with active CaO. This work shows that changes in the texture of the sorbent due to repetitive carbonation/calcination cycles tend to increase the sulfation capacity of the sorbents tested. This suggests that the purge of deactivated CaO obtained from a CO{sub 2} capture loop could be a more effective sorbent of SO{sub 2} than fresh CaO.

  17. Barium hexaferrite nanoparticles: Synthesis and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Martirosyan, K.S., E-mail: karen.martirosyan@utb.edu [Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77204 (United States); Texas Center for Superconductivity, University of Houston, Houston, TX 77204 (United States); Department of Electrical and Computer Engineering, University of Houston, Houston, TX 77204 (United States); Galstyan, E. [Texas Center for Superconductivity, University of Houston, Houston, TX 77204 (United States); Hossain, S.M.; Wang Yiju [Department of Electrical and Computer Engineering, University of Houston, Houston, TX 77204 (United States); Litvinov, D. [Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77204 (United States); Texas Center for Superconductivity, University of Houston, Houston, TX 77204 (United States); Department of Electrical and Computer Engineering, University of Houston, Houston, TX 77204 (United States)

    2011-01-15

    Carbon combustion synthesis is applied to rapid and energy efficient fabrication of crystalline barium hexaferrite nanoparticles with the average particle size of 50-100 nm. In this method, the exothermic oxidation of carbon nanoparticles with an average size of 5 nm with a surface area of 80 m{sup 2}/g generates a self-propagating thermal wave with maximum temperatures of up to 1000 deg. C. The thermal front rapidly propagates through the mixture of solid reactants converting it to the hexagonal barium ferrite. Carbon is not incorporated in the product and is emitted from the reaction zone as a gaseous CO{sub 2}. The activation energy for carbon combustion synthesis of BaFe{sub 12}O{sub 19} was estimated to be 98 kJ/mol. A complete conversion to hexagonal barium ferrite is obtained for carbon concentration exceeding 11 wt.%. The magnetic properties H{sub c}{approx}3000 Oe and M{sub s}{approx}50.3 emu/g of the compact sintered ferrites compare well with those produced by other synthesis methods.

  18. Barium hexaferrite nanoparticles: Synthesis and magnetic properties

    International Nuclear Information System (INIS)

    Carbon combustion synthesis is applied to rapid and energy efficient fabrication of crystalline barium hexaferrite nanoparticles with the average particle size of 50-100 nm. In this method, the exothermic oxidation of carbon nanoparticles with an average size of 5 nm with a surface area of 80 m2/g generates a self-propagating thermal wave with maximum temperatures of up to 1000 deg. C. The thermal front rapidly propagates through the mixture of solid reactants converting it to the hexagonal barium ferrite. Carbon is not incorporated in the product and is emitted from the reaction zone as a gaseous CO2. The activation energy for carbon combustion synthesis of BaFe12O19 was estimated to be 98 kJ/mol. A complete conversion to hexagonal barium ferrite is obtained for carbon concentration exceeding 11 wt.%. The magnetic properties Hc∼3000 Oe and Ms∼50.3 emu/g of the compact sintered ferrites compare well with those produced by other synthesis methods.

  19. New barium tantalum sulphides

    International Nuclear Information System (INIS)

    A new barium tantalum sulphide has been synthesized by the reaction of CS2 with a mixture of BaCO3 and Ta2O5. The chemical analysis of the compound was performed for 3 components (Ba, Ta and S), and the chemical composition was found to be BaTa2S5. The powder X-ray diffraction peaks were indexable on the basis of a hexagonal cell with lattices constants of a=3.32A, c=25.13A. However, the electron diffraction measurements show that the structure is more complex than that observed by powder X-ray diffraction. The compound indicates metallic behavior and Pauli paramagnetism

  20. NANOSCALE BARIUM HYDROSILICATES: CHOOSING THE SYNTHESIS TECHNOLOGY

    Directory of Open Access Journals (Sweden)

    GRISHINA Anna Nikolaevna

    2013-08-01

    Full Text Available Cement concretes are the most used materials in modern civil engineering. Due to that such materials draw great attention both in the Russian Federation and abroad. The possibility to enhance the manufacturability and operational properties of concretes results in significant reduction of overall operating costs. Many enhancement methods have been elaborated. Among them there is one based on introduction of calcium hydrosilicates into construction composition. The authors set up a hypothesis that similarity between properties and structures of different hydrosilicates (for example, alkaline earth metals and metals of the second group will provide similar increased operational characteristics. The specialists of Research and Educational Center «Nanotechnology» are developing cement composites nanomodification methods which include introduction of nanodimensional barium hydrosilicates particles. The synthesis of barium hydrosilicates particles can be done with the use of many technologies, different by energy consumption or performing complexity. Taking into account both these factors, one can assume that low-temperature sol-gel synthesis from diluted water solutions is the proper technology. The present paper shows that this assumption is correct. The selection of certain technology is made by the means of multiobjective optimization, which is in turn is performed by the means of linear scalarization. This method, while not always giving the Pareto optimal solutions, can be easily implemented. The particle size distribution is taken into consideration during selection of objectives and weights. It is shown that selected technology allows manufacturing nanoparticles with median size about 30 nm.

  1. Abundance analysis of barium and mild barium stars

    CERN Document Server

    Smiljanic, R; Silva, L

    2007-01-01

    High signal to noise, high resolution spectra were obtained for a sample of normal, mild barium, and barium giants. Atmospheric parameters were determined from the FeI and FeII lines. Abundances for Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Y, Zr, Ba, La, Ce, Nd, Sm, Eu, and Gd, were determined from equivalent widths and model atmospheres in a differential analysis, with the red giant Eps Vir as the standard star. The different levels of s-process overabundances of barium and mild barium stars were earlier suggested to be related to the stellar metallicity. Contrary to this suggestion, we found in this work no evidence for barium and mild barium to have a different range in metallicity. However, comparing the ratio of abundances of heavy to light s-process elements, we found some evidence that they do not share the same neutron exposure parameter. The exact mechanism controlling this difference is still not clear. As a by-product of this analysis we identify two normal red giants misclass...

  2. Ice nucleation by surrogates for atmospheric mineral dust and mineral dust/sulfate particles at cirrus temperatures

    Directory of Open Access Journals (Sweden)

    C. M. Archuleta

    2005-01-01

    Full Text Available This study examines the potential role of some types of mineral dust and mineral dust with sulfuric acid coatings as heterogeneous ice nuclei at cirrus temperatures. Commercially-available nanoscale powder samples of aluminum oxide, alumina-silicate and iron oxide were used as surrogates for atmospheric mineral dust particles, with and without multilayer coverage of sulfuric acid. A sample of Asian dust aerosol particles was also studied. Measurements of ice nucleation were made using a continuous-flow ice-thermal diffusion chamber (CFDC operated to expose size-selected aerosol particles to temperatures between -45 and -60°C and a range of relative humidity above ice-saturated conditions. Pure metal oxide particles supported heterogeneous ice nucleation at lower relative humidities than those required to homogeneously freeze sulfuric acid solution particles at sizes larger than about 50 nm. The ice nucleation behavior of the same metal oxides coated with sulfuric acid indicate heterogeneous freezing at lower relative humidities than those calculated for homogeneous freezing of the diluted particle coatings. The effect of soluble coatings on the ice activation relative humidity varied with the respective uncoated core particle types, but for all types the heterogeneous freezing rates increased with particle size for the same thermodynamic conditions. For a selected size of 200 nm, the natural mineral dust particles were the most effective ice nuclei tested, supporting heterogeneous ice formation at an ice relative humidity of approximately 135%, irrespective of temperature. Modified homogeneous freezing parameterizations and theoretical formulations are shown to have application to the description of heterogeneous freezing of mineral dust-like particles with soluble coatings.

  3. Barium ferrite nanoparticles prepared by self-propagating low-temperature combustion method and its characterization

    Indian Academy of Sciences (India)

    P M Prithviraj Swamy; S Basavaraja; Vijayanand Havanoor; N V Srinivas Rao; R Nijagunappa; A Venkataraman

    2011-12-01

    The barium ferrite particles were prepared using a self-propagating low-temperature combustion method using polyethylene glycol (PEG) as a fuel. The process was investigated with simultaneous thermogravimetric-differential thermal analysis (TG–DTA). The crystalline structure, morphology and the magnetic properties of the barium ferrite particles were studied by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and SQUID susceptometer. The results show that the ignition temperature of PEG is lower compared with other combustion methods and gives nanocrystalline barium ferrite.

  4. Discovery of the Barium Isotopes

    OpenAIRE

    SHORE, A.; A. Fritsch; Ginepro, J. Q.; Heim, M.; Schuh, A.; Thoennessen, M

    2009-01-01

    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.

  5. Kinetics of thermal decomposition of barium zirconyl oxalate

    International Nuclear Information System (INIS)

    Kinetics of the thermal decomposition of anhydrous barium zirconyl oxalate and a carbonate intermediate have been studied. Decomposition of the anhydrous oxalate, though it could be explained based on a contracting-cube model, is quite complex. Kinetics of decomposition of the intermediate carbonate Ba2Zr2O5CO3 is greatly influenced by thermal effects during its formation. (α-t) curves are sigmoidal and obey a power law equation followed by first order decay. Presence of carbon in the vacuum-prepared carbonate has a strong deactivating effect. Decomposition of the carbonate is accompanied by growth in particle size of the product barium zirconate. (Author)

  6. In vitro investigations for the development of a high-density contrast medium for double contrast barium enema

    International Nuclear Information System (INIS)

    Electron microscope and phantom imaging studies showed, that from microparticle barium sulfate a high-density contrast medium can be produced for double-contrast investigations of the colon. As stabilizing agent a substance with the same physical and chemical action like 0.6 g CMC (sodium carboxymethyl cellulose) per 100 g barium sulfate are to be used. With second stabilizer, having the same effect as mixed pectine, the thickness of the contrast film can be modified, while the flow time of the contrast medium remains constant. Flow curves lead to the conclusion, that a maximum concentration of 140% of weight can be used for the patients. The measurement of density and flow time of the suspension allow to check the high density and low viscosity requirements. The density of the barium sulfates used for investigation was 4,000 g/l. (author)

  7. Barium light source method and apparatus

    Science.gov (United States)

    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.

  8. Preparation of Nanoparticles of Barium Ferrite from Precipitation in Microemulsions

    International Nuclear Information System (INIS)

    Magnetic nanoparticles of barium ferrite (BaFe12O19) have been synthesized using a microemulsion mediated process. The aqueous cores of water-in-oil microemulsions were used as constrained microreactors for the precipitation of precursor carbonate and hydroxide particles. These precursors were then calcined at 925 deg. C for 12 h, during which time they were transformed to the hexagonal ferrite. The pH of reaction was varied between 5 and 12, and it was found that the fraction of non-magnetic hematite (α-Fe2O3) in the particles varied with the pH of reaction, thus affecting the magnetic properties of the particles. The same precursor particles were also prepared by bulk co-precipitation reaction for comparison. It was found that the microemulsion derived nanoparticles of barium ferrite had both higher intrinsic coercivity (Hc) and saturation magnetization (σs) than the particles derived from bulk co-precipitation. Particles were analyzed by electron microscopy, X-ray diffraction, differential thermal analysis (DTA), thermogravimetric analysis (TGA) and vibrating sample magnetometry (VSM). The best barium ferrite particles produced by the microemulsion synthesis method yielded an intrinsic coercivity of 4310 Oe and a saturation magnetization of 60.48 emu/g

  9. Barium hexaferrite ferrofluids - preparation and physical properties

    Science.gov (United States)

    Müller, R.; Hiergeist, R.; Steinmetz, H.; Ayoub, N.; Fujisaki, M.; Schüppel, W.

    1999-07-01

    Barium hexaferrite BaFe 12-2 xTi xCo xO 19 ferrofluids have been prepared for the first time using oleic acid as surfactant and Isopar M ® as carrier liquid. The initial susceptibility versus temperature for zero-field cooling of the ferrofluid was obtained by a vibrating sample magnetometer. TEM pictures of the fluid show isolated particles and only small agglomerates and a mean particle diameter of approx. 8 nm. Numerical calculations of the magneto-viscous effect, based on the local-equilibrium magnetic state model, clearly show the benefit for Ba-ferrite ferrofluids resulting from the high uniaxial anisotropy compared to magnetite ferrofluids. Rheological measurements were performed with a rotational-type viscometer with magnetic field perpendicular to the hydrodynamic vortex axis.

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

    Directory of Open Access Journals (Sweden)

    Carlos Shuler Nin

    2013-12-01

    Full Text Available 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.

  11. Reaction sintering of a zirconia-containing barium feldspar ceramic

    International Nuclear Information System (INIS)

    Zircon (ZrSiO4) is a natural mineral resource known to react with certain oxides to produce a dispersion of zirconia particles within ceramic or glass-ceramic matrices. Barium aluminosilicates, particularly the celsian polymorphs of BaO- Al2O3 2SiO2 display oxidation resistance and refractory characteristics commensurate with the properties required of high temperature materials. Such properties, coupled with the high melting point of ZrO2 (2680 deg C), suggest that barium aluminosilicates and zirconia are an ideal combination from which to fabricate high temperature materials. A recent study has indicated that a barium aluminosilicate containing up to 40mol% ZrO2 can be prepared via a sol-gel process. However, the desire to utilise a natural resource in the form of zircon in the present work has led to the choice of reaction sintering as an alternative processing route. The current work was undertaken to investigate the possibility of forming a zirconia-containing barium feldspar composite material using the reaction sintering of zircon and assuming the following stoichiometric reaction: 2ZrSiO4 + BaCO3 + Al2O3 → 2ZrO2 + BaO-Al2O3-2SiO2 + CO2 ↑. The reaction sintering of zircon with alumina and barium carbonate produces a composite material comprising distributed ZrO2 in a continous barium feldspar matrix. Yttria added during processing allows a significant fraction of the ZrO2 to be retained as tetragonal phase to room temperature and thus the potential for a measure of transformation toughening

  12. Reaction sintering of a zirconia-containing barium feldspar ceramic

    Energy Technology Data Exchange (ETDEWEB)

    Nordmann, A.; Cheng, Y-B.; Muddle, B. C. [Monash Univ., Clayton, VIC (Australia). Dept. of Materials Engineering

    1996-12-31

    Zircon (ZrSiO{sub 4}) is a natural mineral resource known to react with certain oxides to produce a dispersion of zirconia particles within ceramic or glass-ceramic matrices. Barium aluminosilicates, particularly the celsian polymorphs of BaO- Al{sub 2}O{sub 3} 2SiO{sub 2} display oxidation resistance and refractory characteristics commensurate with the properties required of high temperature materials. Such properties, coupled with the high melting point of ZrO{sub 2} (2680 deg C), suggest that barium aluminosilicates and zirconia are an ideal combination from which to fabricate high temperature materials. A recent study has indicated that a barium aluminosilicate containing up to 40mol% ZrO{sub 2} can be prepared via a sol-gel process. However, the desire to utilise a natural resource in the form of zircon in the present work has led to the choice of reaction sintering as an alternative processing route. The current work was undertaken to investigate the possibility of forming a zirconia-containing barium feldspar composite material using the reaction sintering of zircon and assuming the following stoichiometric reaction: 2ZrSiO{sub 4} + BaCO{sub 3} + Al{sub 2}O{sub 3} {yields} 2ZrO{sub 2} + BaO-Al{sub 2}O{sub 3}-2SiO{sub 2} + CO{sub 2} {up_arrow}. The reaction sintering of zircon with alumina and barium carbonate produces a composite material comprising distributed ZrO{sub 2} in a continous barium feldspar matrix. Yttria added during processing allows a significant fraction of the ZrO{sub 2} to be retained as tetragonal phase to room temperature and thus the potential for a measure of transformation toughening. 14 refs., 2 tabs., 6 figs.

  13. Magnetic and structural investigations on barium hexaferrite ferrofluids

    Science.gov (United States)

    Müller, R.; Hiergeist, R.; Gawalek, W.; Hoell, A.; Wiedenmann, A.

    2002-11-01

    Barium hexaferrite BaFe 12-2 xTi xCo xO 19 ferrofluids have been prepared using oleic acid as surfactant and Isopar M ® or dodecane as carrier liquid. The ferrite particles were prepared by glass crystallization. Hysteresis parameters, the initial susceptibility versus temperature and the magnetic particle size were obtained by VSM. Ferrofluids with a partly deuterated carrier liquid were investigated by small angle neutron scattering (SANS). SANS curves lead to a bimodal size distribution consisting of single magnetic particles with an organic shell and aggregated particles with an incomplete organic layer.

  14. A Comparative Study on Magnetostructural Properties of Barium Hexaferrite Powders Prepared by Polyethylene Glycol

    Directory of Open Access Journals (Sweden)

    Zehra Durmus

    2014-01-01

    Full Text Available Nanocrystalline particles of barium hexaferrite were synthesized by a sol-gel combustion route using nitrate-citrate gels prepared from metal nitrates and citric acid solutions with Fe/Ba molar ratio 12. The present paper aims to study the effect of addition of polyethylene glycol (PEG solutions with different molecular weights (MW: 400, 2000, and 10.000 g/mol on magnetostructural properties of barium hexaferrite. The formation of the barium hexaferrite was inspected using X-ray diffraction (XRD analysis, Fourier transform infrared (FT-IR analysis, thermogravimetric (TGA analysis, scanning electron microscopy (SEM analysis and vibrating sample magnetometer (VSM analysis for magnetic measurements.

  15. Barium sulphate preparations for use in double contrast examination of the upper gastrointestinal tract

    International Nuclear Information System (INIS)

    Physical properties relevant to upper gastrointestinal radiology have been compared for five barium sulphate preparations and related to radiographic results. Evaluation of particles (size and stability) and whole suspension (dispersibility and fluidity) resulted in ranking of the preparations generally in accord with that based on radiological experience in double contrast examinations of the stomach. Experiments with extirpated pig stomach revealed a tendency for large particles in a low viscosity barium sulphate suspension to settle in mucosal grooves. This is believed to contribute to good radiographic definition of both the areae gastricae and small lesions. Particle size is therefore important and susceptibility to flocculation, a possible cause of random change in size during use, was assessed by measuring particle electrophoretic mobility under varying conditions; quantitative differences in suspension flow and dispersibility were also demonstrated. Fluidity and dispersibility together with rapid sedimentation of suitably sized particles resistant to flocculation underlie the successful use of low viscosity high density barium sulphate suspensions. (U.K.)

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

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Nyoung Keun; Park, Chang Min; Kang, Chang Hyun; Jeon, Yoon Kyung; Choo, Ji Yung; Lee, Hyun Ju; Goo, Jin Mo [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2012-11-15

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

  17. Effect of Sodium Dodecyl Sulfate Adsorption on the Behavior of Water inside Single Walled Carbon Nanotubes with Dissipative Particle Dynamics Simulation.

    Science.gov (United States)

    Vo, Minh D; Papavassiliou, Dimitrios V

    2016-01-01

    Dissipative particle dynamics (DPD) simulations were utilized to investigate the ability of sodium dodecyl sulfate (SDS) to adsorb inside a single-walled, arm-chair carbon nanotube (SWCNT), as well as the effect of surfactant on the properties of water inside the SWCNT. The diameter of the SWCNT varied from 1 to 5 nm. The radial and axial density profiles of water inside the SWCNTs were computed and compared with published molecular dynamics results. The average residence time and diffusivity were also calculated to show the size effect on mobility of water inside the SWCNT. It was found that nanotubes with diameter smaller than 3 nm do not allow SDS molecules to enter the SWCNT space. For larger SWCNT diameter, SDS adsorbed inside and outside the nanotube. When SDS was adsorbed in the hollow part of the SWCNT, the behavior of water inside the nanotube was found to be significantly changed. Both radial and axial density profiles of water inside the SWCNT fluctuated strongly and were different from those in bulk phase. In addition, SDS molecules increased the retention of water beads inside SWCNT (d ≥ 3nm) while water diffusivity was decreased. PMID:27092476

  18. Effect of Sodium Dodecyl Sulfate Adsorption on the Behavior of Water inside Single Walled Carbon Nanotubes with Dissipative Particle Dynamics Simulation

    Directory of Open Access Journals (Sweden)

    Minh D. Vo

    2016-04-01

    Full Text Available Dissipative particle dynamics (DPD simulations were utilized to investigate the ability of sodium dodecyl sulfate (SDS to adsorb inside a single-walled, arm-chair carbon nanotube (SWCNT, as well as the effect of surfactant on the properties of water inside the SWCNT. The diameter of the SWCNT varied from 1 to 5 nm. The radial and axial density profiles of water inside the SWCNTs were computed and compared with published molecular dynamics results. The average residence time and diffusivity were also calculated to show the size effect on mobility of water inside the SWCNT. It was found that nanotubes with diameter smaller than 3 nm do not allow SDS molecules to enter the SWCNT space. For larger SWCNT diameter, SDS adsorbed inside and outside the nanotube. When SDS was adsorbed in the hollow part of the SWCNT, the behavior of water inside the nanotube was found to be significantly changed. Both radial and axial density profiles of water inside the SWCNT fluctuated strongly and were different from those in bulk phase. In addition, SDS molecules increased the retention of water beads inside SWCNT (d ≥ 3nm while water diffusivity was decreased.

  19. Sulfur Isotopic Compositions of Individual Aerosol Particles from Below and Within Stratocumulus Clouds over the Southeast Pacific Ocean During VOCALS

    Science.gov (United States)

    Bose, M.; Anderson, J. R.; Twohy, C. H.; Williams, P.

    2012-12-01

    The VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-Rex) was a large multi-national field experiment that collected data and samples from a region of the southeast Pacific with the world's largest stratocumulus cloud systems. Samples examined here are residues of cloud droplets and ambient particles from below the clouds collected during flights of the NCAR C-130 off the coast of Chile. Selected samples were studied using scanning electron microscopy (SEM) and secondary ion mass spectrometry (SIMS) in order to contribute to the understanding of the source of non-sea-salt sulfate in this region. Particles in the size range from 0.2 to 1μm diameter on holey and lacey carbon were characterized by SEM combined with energy dispersive spectrometry (EDS), thus identifying sulfur-containing particles. Subsequently, sulfur ion imaging of identified sea salt, ammonium sulfate and sodium sulfate particles was done with the Cameca Ametek NanoSIMS 50L at Arizona State University. A electrons were collected simultaneously at high mass resolution (m/Δm>10000). Each measurement typically consists of 5 to 8 frames (~5.4 min/frame). NIST barium sulfate and ammonium sulfate particles were used as isotopic standards. Preliminary analyses on a small pool of VOCALS individual particles show a wide range in sulfur isotopic compositions (δ34S = -56 to +41‰). In addition, the in-cloud particles are enriched in 32S, while the ambient particles exhibit 34S excesses. Isotopic data on a large inventory of particles is being currently acquired, which will be presented at the meeting. Data will be used to investigate sulfur sources (marine vs. continental) and the processing of aerosols through sulfate formation.

  20. Microstructure and magnetic properties of commercial barium ferrite powders

    Directory of Open Access Journals (Sweden)

    R. Nowosielski

    2007-01-01

    Full Text Available Purpose: Microstructural and magnetic properties analysis of commercial barium ferrite powder BaFe12O19.Design/methodology/approach: The X-ray diffraction methods were utilized not only for qualitative andquantitative phase analysis of studied powder sample, but also for the determination of lattice parameters, crystallitesize and the lattice distortion. The Rietveld method was used in the verification of the qualitative phase compositionand in the determination of phase abundance. Hill and Howard procedure was applied for quantitative phaseanalysis. The parameters of the individual diffraction line profiles were determined by PRO-FIT Toraya procedure.The morphology of barium ferrite powders was analyzed using the scanning electron miroscopy (SEM method.The distribution of powder particles was determined by a laser particle analyzer. Moreover, the magnetic hysteresisloop of examined powder material were measured by resonance vibrating sample magnetometer (R-VSM.Findings: The X-ray diffraction analysis revealed the presence of hexagonal BaFe12O19 and rhombohedralFe2O3 phases in examined powder samples. The barium ferrite phase appeared to be the main component of thesamples (97.8 wt.%. The crystallite size of BaFe12O19 phase is above 100 nm. The size of studied powders isin the range from 0.2 μm to 40.5 μm. The arithmetic mean diameter of BaFe12O19 powders population is 10.335μm. The SEM images showed irregular shape and size of powder particles. The coercive force (HC obtainedfrom hysteresis loop has a value about 159 kA/m.Practical implications: Structure analysis of commercial barium ferrite powder is helpful to prepare thismaterial by laboratory methods.Originality/value: The obtained results of investigations by different methods of structure characterizationconfirm their utility in the microstructure analysis of powder materials.

  1. The problem of the barium stars

    Science.gov (United States)

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

    1984-01-01

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

  2. Radioisotope barium sulphate gauge MZB-2

    International Nuclear Information System (INIS)

    A method and the gauge for measuring content of barium sulphate are described. The gauge is intended for fast determination of barium sulphate in barite ore and in output products of the enrichment process. The measuring range 60-100% of BaSO4, accuracy ±1% and measuring time 60 s were reached. The barium sulphate gauge is used in barite mine ''Boguszow'' in Poland. (author)

  3. ONE CASE REPORT OF ACUTE POISONING BY BARIUM CARBONATE

    Institute of Scientific and Technical Information of China (English)

    GE Qin-min; BIAN Fan; WANG Shu-yun; SHEN Sheng-hui

    2009-01-01

    @@ Most barium poisoning cases were caused by oral intake by mistake. Recent years, barium carbonate poisoning has been rare to be reported. Here we reported a case of acute barium carbonate toxication taken orally on purpose.

  4. Barium ferrite powders prepared by milling and annealing

    Directory of Open Access Journals (Sweden)

    R. Nowosielski

    2007-05-01

    Full Text Available Purpose: Microstructure and magnetic properties analysis of barium ferrite powder obtained by milling and heat treatment.Design/methodology/approach: The milling process was carried out in a vibratory mill, which generated vibrations of the balls and milled material inside the container during which their collisions occur. After milling process the powders were annealed in electric chamber furnace. The X-ray diffraction methods were used for qualitative phase analysis of studied powder samples. The distribution of powder particles was determined by a laser particle analyzer. The magnetic hysteresis loops of examined powder material were measured by resonance vibrating sample magnetometer (R-VSM.Findings: The milling process of iron oxide and barium carbonate mixture causes decrease of the crystallite size of involved phases. The X-ray investigations of tested mixture milled for 30 hours and annealed at 950 °C enabled the identification of hard magnetic BaFe12O19 phase and also the presence of Fe2O3 phase in examined material. The Fe2O3 phase is a rest of BaCO3 dissociation in the presence of Fe2O3, which forms a compound of BaFe12O19. The best coercive force (HC for mixture of powders annealed at 950 °C for 10, 20 and 30 hours is 349 kA/m, 366 kA/m and 364 kA/m, respectively. The arithmetic mean of diameter of Fe2O3 and BaCO3 mixture powders after 30 hours of milling is about 6.0 μm.Practical implications: The barium ferrite powder obtained by milling and annealing can be suitable components to produce sintered and elastic magnets with polymer matrix.Originality/value: The results of tested barium ferrite investigations by different methods confirm their utility in the microstructure and magnetic properties analysis of powder materials.

  5. Barium Depletion in Hollow Cathode Emitters

    Science.gov (United States)

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

    2009-01-01

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

  6. Preparation of porous nano barium ferrite and its adsorption properties on uranium

    International Nuclear Information System (INIS)

    The porous nano barium ferrite was made of Fe(NO3)3 and Ba(NO3)2 as raw materials, CTAB as surfactant by method of sol-gel and self-propagating combustion. The composition, morphology and magnetic properties of nano-rod barium ferrite were characterized by XRD, SEM and vibrating sample magnetometer. The adsorption properties of porous nano barium ferrite on uranium were studied with static adsorption and the effects of pH, adsorption temperature and oscillation time on adsorption properties were discussed. The results indicate that the average particle size of porous nano barium ferrite is 45-65 nm, the saturation magnetization and coercivity are 62.83 emu/g and 5481.0 Oe, respectively. Under the condition of the porous nano barium ferrite amount of 0.02 g, pH of 6, adsorption temperature of 25℃ and oscillation time of 30 min, the adsorption capacity of uranium on the porous nano barium ferrite reaches 921 μg/g. (authors)

  7. Processing science of barium titanate

    Science.gov (United States)

    Aygun, Seymen Murat

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

  8. Barium methylphosphonates: synthesis, characterization and mutual interconversions

    Czech Academy of Sciences Publication Activity Database

    Beneš, L.; Melánová, Klára; Svoboda, Jan; Zima, Vítězslav

    Strasbourg: University of Strasbourg, Francie, 2015. P64. [ISIC18 International Symposium on Intercalation Compounds. 31.05.2015-04.06.2015, Strasbourg] R&D Projects: GA ČR(CZ) GA14-13368S Institutional support: RVO:61389013 Keywords : hydrates of barium methylphosphonate * barium hydrogen methylphosphonate * powder X-ray diffraction Subject RIV: CA - Inorganic Chemistry

  9. Fabrication and electrical characterization of 15% yttrium-doped barium zirconate-nitrate freeze drying method combined with vacuum heating

    International Nuclear Information System (INIS)

    Research highlights: → Very fine 15% yttrium-doped barium zirconate powder of particle size about 30 nm was obtained by synthesizing at 500 deg. C in vacuum from powder mixed by the nitrate freeze-drying method. → Large and homogeneous grains of 15% yttrium-doped barium zirconate were easily obtained using the synthesized powder. → Grain boundary resistance was not inversely proportional to the grain size as theoretically expected. → Specific grain boundary conductivity varies with samples because impurities and/or evaporation loss of barium oxide might affect the grain-boundary resistance in 15% yttrium-doped barium zirconate. - Abstract: We applied a nitrate freeze-drying method to obtain a fine synthesized powder of 15% yttrium-doped barium zirconate. Fine 15% yttrium-doped barium zirconate powder of particle size about 30 nm was obtained by synthesizing at 500 deg. C in vacuum from a powder mixed by the nitrate freeze-drying method. However, we could not obtain such fine powder by synthesizing in air. Using the powder synthesized in vacuum, large and homogeneous grains of 15% yttrium-doped barium zirconate were easily obtained after sintering. Then, the bulk and grain boundary resistance were evaluated by AC 2-terminal measurement of sample in the form of bar and pellet and DC 4-terminal measurement of bar-shape sample. The grain boundary resistance was not inversely proportional to the grain size as theoretically expected. We concluded that specific grain boundary conductivity varies with samples. Some impurities, evaporation loss of barium oxide and/or other unexpected reasons might affect the grain boundary resistance in 15% yttrium-doped barium zirconate.

  10. Ultrasonic de-agglomeration of barium titanate powder.

    Science.gov (United States)

    Marković, S; Mitrić, M; Starcević, G; Uskoković, D

    2008-01-01

    BaTiO3 (BT) powder, with average particle size of 1.4 microm, was synthesized by solid-state reaction. A high-intensity ultrasound irradiation (ultrasonication) was used to de-agglomerate micro-sized powder to nano-sized one. The crystal structure, crystallite size, morphology, particle size, particle size distribution, and specific surface area of the BT powder de-agglomerated for different ultrasonication times (0, 10, 60, and 180 min) were determined. It was found that the particles size of the BT powder was influenced by ultrasonic treatment, while its tetragonal structure was maintained. Therefore, ultrasonic irradiation can be proposed as an environmental-friendly, economical, and effective tool for the de-agglomeration of barium titanate powders. PMID:17845864

  11. A new double contrast barium enema

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jun Sang; Cho, Won Sik; Lee, Sung Woo; Lee, Mun Gyu; Jeon, Jeong Dong; Jaun, Woo Ki; Han, Chung Yul [Inje College Paik Hospital, Pusan (Korea, Republic of)

    1987-12-15

    A new technic of the barium enema was proposed for the better colonic double contrast study with the average 204ml of 50w/v% barium, applied to 109 serial patients. The barium was introduced to sigmoid colon, and then pushed to a mid transverse colon by the air insufflation through an enema syringe, a new device. An advance to cecum is accomplished by the air insufflation and/or the position change of the patient. The barium transfer method was developed for the best spot film exposure, through colon, by the position change of the patient, the tilting of the x-ray table and the air insufflation with the enema syringe. The mean angle of the x-ray table tilted was -10 .deg. at the beginning the barium enema till the barium sent past the splenic flexure, -15 . deg. for the best lateral view of rectum and -18 .deg. for the bet prone PA view of rectosigmoid colon. This was a simple, better and economic double contrast barium enema for the cooperative patients.

  12. Synthesis of barium titanium oxide from barium sulphate and anatase. Study of equimolar mixtures under different atmospheres

    International Nuclear Information System (INIS)

    To enable the ceramization of a barium sulphate-rich radioactive waste the synthesis of barium titanium oxide is studied by using anatase and barium sulphate. As a function of the calcination atmosphere, helium (or air) and Ar/H2, two reactions are studied. A mechanism of barium titanium oxide synthesis in helium (or in air) is proposed

  13. Magnetoresistance studies on barium doped nanocrystalline manganite

    International Nuclear Information System (INIS)

    An energetically attractive, simple, fast and a novel low temperature (300 deg. C) solution combustion route for the synthesis of crystalline and homogeneous nanoparticles of lanthanum barium manganese oxide La0.9Ba0.1MnO3+δ (LBMO) is reported. Formation and homogeneity of the solid solutions have been confirmed by powder X-ray diffraction (PXRD) and energy dispersive X-ray analysis (EDS) respectively. The Rietveld analysis shows both as-formed as well as calcined samples are in cubic phase with space group pm3m. The microstructure and agglomerated particle size of the compounds are examined by scanning electron microscope. Infrared spectroscopy revealed that both Mn-O-Mn bending mode and Mn-O stretching mode are influenced by calcination temperature. The magnetoresistance measurement on sintered LBMO pellet exhibits a broad metal-insulator transition (TM-I) at around 228 K. At 1 T applied magnetic field, LBMO shows magnetoresistance (MR) of 10%, whereas for 4 and 7 T, the negative magnetoresistance values are in the range 51 and 59% respectively at TM-I. The experimental resistivity data of the present investigation are fitted to a simple empirical equation in order to understand conduction mechanism in this compound

  14. Double contrast barium meal and acetylcysteine

    International Nuclear Information System (INIS)

    In a prospective double blind study, acetylcysteine, a local and systemic respiratory tract mucolytic agent, or a placebo, were given to 100 patients prior to a double contrast barium meal to decrease the gastric mucus viscosity and to make the mucus layer thinner, in order to permit barium to outline the furrows surrounding the areae gastricae instead of the overlying thick mucus. However, acetylcysteine failed to improve either visualization of the areae gastricae or the general quality of the double contrast barium meal. (orig.)

  15. Barium adsorption on the (110) and (111) molybdenum faces

    Energy Technology Data Exchange (ETDEWEB)

    Azizov, U.V.; Sabirov, S.T.; Dzhalilov, S.T. (Tashkentskij Gosudarstvennyj Univ. (USSR))

    1982-07-01

    Barium adsorption on Mo faces (110) and (111) was investigated by thermoemission and Cs surface ionization methods to obtain a more broad representation of barium adsorption at higher temperatures of cathode. Experiments show that the substrate temperature increase at a constant barium concentration results in the formation of small barium islands. At that, barium is under similar energy conditions in the small islands formed on the face (110) independent of relative areas of the islands.

  16. Barium strontium titanate powders prepared by spray pyrolysis

    International Nuclear Information System (INIS)

    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 were submicronic, consisting of spherical, polycrystalline particles, with internal nanocrystalline structure. Crystallite size of 10 nm, calculated using Rietveld refinement, is in a good agreement with results of HRTEM

  17. Studies on characterization, microstructures and magnetic properties of nano-size barium hexa-ferrite prepared through a hydrothermal precipitation-calcination route

    International Nuclear Information System (INIS)

    An attempt was made to prepare nano-size barium hexa-ferrite particles following a hydrothermal precipitation-calcination route using barium and iron nitrate solutions. During hydrothermal treatment at 180 deg. C (2 h precipitation time) barium carbonate and hematite phases were formed. This precursor was calcined at 800, 1000 and 1200 deg. C to determine the conditions for obtaining barium hexa-ferrite. The characterization studies on calcined products revealed that up to 800 deg. C, the major crystalline phases (barium carbonate and hematite) of the precursor were retained. At 1000 deg. C, formation of barium hexa-ferrite started and at 1200 deg. C, though most of the major peaks of X-ray diffractogram corresponded to barium hexa-ferrite, a number of peaks corresponding to hematite were also present. Some low intensity peaks for barium carbonate were observed. The average particle size was 40 nm. Saturation magnetization, remanence magnetization and coercivity were found to be 40.0, 21.6 emu g-1 and 2.87 kOe, respectively. The values obtained both for coercivity and magnetization for the present sample were lower than the reported bulk values which could be due to the fact that the sample prepared through the present technique was not mono-phasic

  18. Barium Isotopes in Single Presolar Grains

    Science.gov (United States)

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

    2001-01-01

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

  19. The structural properties of barium cobalt hexaferrite powder prepared by a simple heat treatment method

    Science.gov (United States)

    Chauhan, Chetna; Jotania, Rajshree

    2016-05-01

    The W-type barium hexaferrite was prepared using a simple heat treatment method. The precursor was calcinated at 650°C for 3 hours and then slowly cooled to room temperature in order to obtain barium cobalt hexaferrite powder. The prepared powder was characterised by different experimental techniques like XRD, FTIR and SEM. The X-ray diffractogram of the sample shows W-and M phases. The particle size calculated by Debye Scherrer formula. The FTIR spectra of the sample was taken at room temperature by using KBr pallet method which confirms the formation of hexaferrite phase. The morphological study on the hexaferrite powder was carried out by SEM analysis.

  20. Solvothermal synthesis and Curie temperature of monodispersed barium titanate nanoparticles

    International Nuclear Information System (INIS)

    Barium titanate (BaTiO3) nanoparticles with various particle sizes were prepared by a solvothermal method. X-ray powder diffraction (XRPD) patterns show that the as-prepared powders are of pure perovskite BaTiO3. Scanning electron microscopy (SEM) reveals that all the particles of BaTiO3 with different sizes are dispersed homogenously and have uniform size. The room temperature and in situ high temperature XRD analyses indicate that both the proportion of the tetragonal phase and the Curie temperature of BaTiO3 increase with increasing particles size. The effects of the reaction parameters, such as the concentration of reactants, the polarity of solvent, the reaction temperature and the amount of surfactant, on the size, morphology and uniformity of BaTiO3 nanoparticles are studied in detail.

  1. Unexpected finding of barium sulphate on the surface of a microspinal catheter

    International Nuclear Information System (INIS)

    During a study with a scanning electron microscope to evaluate the structure of microspinal catheter after its removal from subarachnoid space, we found an unusual case. The observation with the microscope of the tip of a catheter removed at the end of an operation for hip replacement in a old female showed the presence of grounded particles with a crystal shape covering the outer surface. Further analysis of this material with an Energy-Dispersive Spectrometer (EDS) showed that it was barium. The patient performed a large bowel barium enema 8 months earlier for a painful syndrome to the lower abdomen. Authors rule out the contamination from the skin and suggest two possible mechanisms of passage of barium from blood to cerebrospinal fluid (CSF) and so to the surface of the catheter

  2. Bacterial Reduction Of Barium Sulphate By Sulphate-Reducing Bacteria

    Directory of Open Access Journals (Sweden)

    Luptáková Alena

    2015-12-01

    Full Text Available Acid mine drainage (AMD is a worldwide problem leading to contamination of water sources. AMD are characterized by low pH and high content of heavy metals and sulphates. The barium salts application presents one of the methods for the sulphates removing from AMD. Barium chloride, barium hydroxide and barium sulphide are used for the sulphates precipitation in the form of barium sulphate. Because of high investment costs of barium salts, barium sulphide is recycled from barium sulphate precipitates. It can be recycled by thermic or bacterial reduction of barium sulphate. The aim of our study was to verify experimentally the possibility of the bacterial transformation of BaSO4 to BaS by sulphate-reducing bacteria. Applied BaSO4 came from experiments of sulphates removal from Smolnik AMD using BaCl2.

  3. Venous barium embolization, a rare, potentially fatal complication of barium enema: 2 case reports

    International Nuclear Information System (INIS)

    Venous embolization of barium has been recognized for 4 decades as one of the most dreaded complications of barium enema. Fortunately, the condition is extremely rare. In this report, the radiographic findings in 2 cases of venous embolization (one involving the portal vein and one systematic) are described, and ways to decrease the risk of this complication are discussed. (author)

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

    Science.gov (United States)

    Ota, K.; Conger, W. L.

    1977-01-01

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

  5. Formation of the natural sulfate aerosol

    Energy Technology Data Exchange (ETDEWEB)

    Kerminen, V.M.; Hillamo, R.; Maekinen, M.; Virkkula, A.; Maekelae, T.; Pakkanen, T. [Helsinki Univ. (Finland). Dept. of Physics

    1996-12-31

    Anthropogenic sulfate aerosol, together with particles from biomass burning, may significantly reduce the climatic warming due to man-made greenhouse gases. The radiative forcing of aerosol particles is based on their ability to scatter and absorb solar radiation (direct effect), and on their influences on cloud albedos and lifetimes (indirect effect). The direct aerosol effect depends strongly on the size, number and chemical composition of particles, being greatest for particles of 0.1-1 {mu}m in diameter. The indirect aerosol effect is dictated by the number of particles being able to act as cloud condensation nuclei (CCN). For sulfate particles, the minimum CCN size in tropospheric clouds is of the order of 0.05-0.2 {mu}m. To improve aerosol parameterizations in future climate models, it is required that (1) both primary and secondary sources of various particle types will be characterized at a greater accuracy, and (2) the influences of various atmospheric processes on the spatial and temporal distribution of these particles and their physico-chemical properties are known much better than at the present. In estimating the climatic forcing due to the sulfate particles, one of the major problems is to distinguish between sulfur from anthropogenic sources and that of natural origin. Global emissions of biogenic and anthropogenic sulfate pre-cursors are comparable in magnitude, but over regional scales either of these two source types may dominate. The current presentation is devoted to discussing the natural sulfate aerosol, including the formation of sulfur-derived particles in the marine environment, and the use of particulate methanesulfonic acid (MSA) as a tracer for the natural sulfate

  6. Synthesis of barium mercaptides and application of antimony/barium mercaptides

    Institute of Scientific and Technical Information of China (English)

    瞿龙; 张露露; 舒万艮

    2001-01-01

    Mercaptoacetic acid, isooctyl thioglycolate and barium hydroxide used as start materials, barium bis (2-ethylhexyl thioglycolate) (Ba(2EHTG)2), barium thioglycolate (Ba(TG)) and barium bisthioglycolate (Ba(TG)2) were synthesized. Their optimum synthetic techniques were discussed, and some physicochemical data were reported. Infrared spectroscopy and elemental analysis methods were used to identify the structures. They were put into PVC plastic products together with antimony tris (2-ethylhexyl thioglycolate) (Sb(2EHTG)3) under the suitable compounding, and their heat stability to PVC was studied. It is shown that these barium mercaptides have remarkable synergisms with antimony mercaptides and the long-term stabilizing effect of organoantimony stabilizer can be effectively improved, reducing the amount of antimony compounds so as to avoid the decrease of its stabilizing effect.

  7. Chemical abundances and kinematics of barium stars

    Science.gov (United States)

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

    2016-04-01

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

  8. Chemical abundances and kinematics of barium stars

    Science.gov (United States)

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

    2016-07-01

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

  9. Spherical barium ferrite nanoparticles and hexaferrite single crystals for information data storage and RF devices

    Science.gov (United States)

    Jalli, Jeevan Prasad

    Since their discovery in the early 1950's hexagonal ferrites or hexaferrites have been studied for a long time because of their technological applications, such as microwave devices and high density magnetic recording media. In this dissertation efforts have been made to address these two applications by developing nanosized spherical barium ferrite particles for advanced magnetic recording media, and hexaferrite single crystals for low loss RF devices. Accordingly, this dissertation consists of two parts; part one spherical barium ferrite nanoparticles for information data storage media, and part two hexaferrite single crystals for RF devices. Part I. Spherical Barium Ferrite Nanoparticles Hexagonal barium ferrite (H-BaFe) nanoparticles are good candidates for particulate recording media due to their high uniaxial magnetocrystalline anisotropy, excellent chemical stability, and narrow switching field distribution. One major disadvantage of using H-BaFe particles for particulate recording media is their poor dispersion and a high degree of stacking that deteriorate the recording capability by creating large media noise and surface roughness. One way to solve and improve the recording performance of H-BaFe media is employing substantially nanosized spherical barium ferrite (S­BaFe) particles. Spherical shaped particles have low aspect ratio and only form a point-to-point contact, unlike the H-BaFe particles. Therefore, using S-BaFe particles not only decrease the degree of magnetic interaction between the particles but also can substantially increases the recording performance by improving the dispersion and SNR of the particles in the magnetic media. In this dissertation, two different approaches were employed successfully to synthesize S-BaFe nanoparticles in the range of 20-45 nm. Part II. Hexaferrite Single Crystals As wireless communication systems are flourishing, and the operating frequencies are increasing, there is a great demand for RF devices such as

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

    International Nuclear Information System (INIS)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Jeet, Suninder, E-mail: suninder.jeet@thapar.edu; Pandey, O. P., E-mail: oppandey@thapar.edu [School of Physics and Materials Science, Thapar University, Patiala (147003), Punjab (India); Sharma, Manoj, E-mail: manojnarad@sggswu.org [Department of Nanotechnology, Sri Guru Granth Sahib World University, Fatehgarh Sahib(146406), Punjab (India)

    2015-05-15

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

  12. Microstructure of polymer composite with barium ferrite powder

    Directory of Open Access Journals (Sweden)

    R. Nowosielski

    2008-12-01

    Full Text Available Purpose: The aim of the paper is the microstructure characterization of commercial BaFe12O19 powder and its composite material in polymer matrix; XRD (X-Ray Diffraction and SEM (Scanning Electron Microscopy methods were applied.Design/methodology/approach: The Rietveld method appeared to be very useful in the verification of the qualitative phase composition and in the determination of phase abundance. Hill and Howard procedure was applied for quantitative phase analysis. The parameters of the individual diffraction line profiles were determined by PRO-FIT Toraya procedure. The morphology of barium ferrite powders and a fracture surface of the examined composite material was analyzed using the scanning electron microscope.Findings: The X-ray diffraction analysis enabled the identification of BaFe12O19 and Fe2O3 phases in examined material. Basing on Rietveld and Toraya methods the determination of lattice parameters, crystallite size and the lattice distortion was performed. Distribution of powders of barium ferrite in polymer matrix is irregular and powder particles are of irregular shapes and different sizes.Research limitations/implications: Maked researches are limited only to characterization the microstructure of commercial material, because obtained results will be helpful to prepare barium ferrite powders by mechanical alloying and subsequent annealing in the future. As prepared BaFe12O19 powders will be used as the starting material for magnets bonded with polymer material.Originality/value: The obtained results of investigations by different methods of structure analysis confirm their useful in the microstructure analysis of powder materials.

  13. Fe and S K-edge XAS determination of iron-sulfur species present in a range of acid sulfate soils: Effects of particle size and concentration on quantitative XANES determinations

    Science.gov (United States)

    Morgan, Kate E.; Burton, Edward D.; Cook, Perran; Raven, Mark D.; Fitzpatrick, Robert W.; Bush, Richard; Sullivan, Leigh A.; Hocking, Rosalie K.

    2009-11-01

    Acid sulfate soils (ASS) are soils and soft sediments in which sulfuric acid may be produced from iron sulfides or have been produced leaving iron oxyhydroxysulfates in amounts that have a long lasting effect on soil characteristics. If soil material is exposed to rotting vegetation or other reducing material, the Fe-oxyhydroxysulfates can be bacterially reduced to sulfides including disulfides (pyrite and marcasite), and Monosulfidic Black Ooze (MBO) a poorly characterised material known to be a mixture of iron sulfides (especially mackinawite) and organic matter. The chemistry of these environments is strongly affected by Fe and S cycling processes and herein we have sought to identify key differences in environments that occur as a function of Fe and S concentration. In addition to our chemical results, we have found that the effects of particle size on self absorption in natural sediments play an important role in the spectroscopic identification of the relative proportions of different species present.

  14. Fe and S K-edge XAS determination of iron-sulfur species present in a range of acid sulfate soils: Effects of particle size and concentration on quantitative XANES determinations

    International Nuclear Information System (INIS)

    Acid sulfate soils (ASS) are soils and soft sediments in which sulfuric acid may be produced from iron sulfides or have been produced leaving iron oxyhydroxysulfates in amounts that have a long lasting effect on soil characteristics. If soil material is exposed to rotting vegetation or other reducing material, the Fe-oxyhydroxysulfates can be bacterially reduced to sulfides including disulfides (pyrite and marcasite), and Monosulfidic Black Ooze (MBO) a poorly characterised material known to be a mixture of iron sulfides (especially mackinawite) and organic matter. The chemistry of these environments is strongly affected by Fe and S cycling processes and herein we have sought to identify key differences in environments that occur as a function of Fe and S concentration. In addition to our chemical results, we have found that the effects of particle size on self absorption in natural sediments play an important role in the spectroscopic identification of the relative proportions of different species present.

  15. 40 CFR 721.10011 - Barium calcium manganese strontium oxide.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Barium calcium manganese strontium... Specific Chemical Substances § 721.10011 Barium calcium manganese strontium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as barium...

  16. Coprecipitation of iron and silver with barium fluoride

    International Nuclear Information System (INIS)

    Distribution of trace contaminants of iron and silver at coprecipitation of barium fluoride is studied in present work. It is defined that iron almost completely coprecipitated with barium fluoride in wide range of ph 5.5-12. Silver coprecipitated with barium fluoride in ph range 4-7. The value of coprecipitation varies from 94% to 100%.

  17. Printed Barium Strontium Titanate capacitors on silicon

    International Nuclear Information System (INIS)

    In this paper, we show that Barium Strontium Titanate (BST) films can be prepared by inkjet printing of sol–gel precursors on platinized silicon substrate. Moreover, a functional variable capacitor working in the GHz range has been made without any lithography or etching steps. Finally, this technology requires 40 times less precursors than the standard sol–gel spin-coating technique. - Highlights: • Inkjet printing of Barium Strontium Titanate films • Deposition on silicon substrate • Inkjet printed silver top electrode • First ever BST films thinner than 1 μm RF functional variable capacitor that has required no lithography

  18. Printed Barium Strontium Titanate capacitors on silicon

    Energy Technology Data Exchange (ETDEWEB)

    Sette, Daniele [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054 Grenoble (France); Luxembourg Institute of Science and Technology LIST, Materials Research and Technology Department, L-4422 Belvaux (Luxembourg); Kovacova, Veronika [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054 Grenoble (France); Defay, Emmanuel, E-mail: emmanuel.defay@list.lu [Univ. Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054 Grenoble (France); Luxembourg Institute of Science and Technology LIST, Materials Research and Technology Department, L-4422 Belvaux (Luxembourg)

    2015-08-31

    In this paper, we show that Barium Strontium Titanate (BST) films can be prepared by inkjet printing of sol–gel precursors on platinized silicon substrate. Moreover, a functional variable capacitor working in the GHz range has been made without any lithography or etching steps. Finally, this technology requires 40 times less precursors than the standard sol–gel spin-coating technique. - Highlights: • Inkjet printing of Barium Strontium Titanate films • Deposition on silicon substrate • Inkjet printed silver top electrode • First ever BST films thinner than 1 μm RF functional variable capacitor that has required no lithography.

  19. Study of barium bismuth titanate prepared by mechanochemical synthesis

    Directory of Open Access Journals (Sweden)

    Lazarević Z.Ž.

    2009-01-01

    Full Text Available Barium-bismuth titanate, BaBi4Ti4O15 (BBT, a member of Aurivillius bismuth-based layer-structure perovskites, was prepared from stoichiometric amounts of barium titanate and bismuth titanate obtained via mechanochemical synthesis. Mechanochemical synthesis was performed in air atmosphere in a planetary ball mill. The reaction mechanism of BaBi4Ti4O15 and the preparation and characteristics of BBT ceramic powders were studied using XRD, Raman spectroscopy, particle analysis and SEM. The Bi-layered perovskite structure of BaBi4Ti4O15 ceramic forms at 1100 °C for 4 h without a pre-calcination step. The microstructure of BaBi4Ti4O15 exhibits plate-like grains typical for the Bi-layered structured material and spherical and polygonal grains. The Ba2+ addition leads to changes in the microstructure development, particularly in the change of the average grain size.

  20. Microstructure of composite material with powders of barium ferrite

    Directory of Open Access Journals (Sweden)

    R. Nowosielski

    2006-04-01

    Full Text Available Purpose: The aim of the present work is the microstructure characterization of commercial powder BaFe12O19 (as-prepared and composite material with BaFe12O19 powders and polymer matrix, using XRD (X-Ray Diffraction and SEM (Scanning Electron Microscopy methods.Design/methodology/approach: The morphology of barium ferrite powders and a fracture surface of the examined composite material was realized by using the scanning electron microscope. The methods of X-ray diffraction were used for the qualitative phase analysis. The parameters of diffraction line profiles were determined by PRO-FIT Toraya procedure.Findings: The X-ray diffraction analysis permitted on identification the BaFe12O19 and Fe2O3 phases in an examined material. Basing on Toraya method is determination of: lattice parameters, crystallite size (D and the lattice distortion (. Distribution of powders of barium ferrite in polymer matrix is irregular and powder particles have irregular shapes and dimensions.Research limitations/implications: For future research the X-ray analysis should be performed by the Rietveld method, which allows to characterization the microstructure of tested material and verification of its qualitative phase composition.Originality/value: The applied Toraya method of structure analysis appeared to be very useful in the microstructure analysis.

  1. An assessment of the redistribution of Barium during diagenesis of Marcellus Shale

    Science.gov (United States)

    Renock, D.; Symcox, C.; Lanids, J. D.; Sharma, M.

    2012-12-01

    Produced water from the hydrofracturing of Marcellus Shale have been reported to contain barium at concentrations >4000 ppm (Gregory et al, 2011). Understanding the reactions responsible for the leaching of Ba into produced water is important for improving the economic viability of gas extraction and to mitigate environmental concerns. Core samples of Marcellus Shale from New York and Pennsylvania were shown to contain Ba in the range of 400-2200 μg/g. In some of these samples, barite (BaSO4) grains are shown to be partially replaced by pyrite (massive and framboidal varieties) suggesting that Ba is remobilized in the zone of sulfate reduction sometime after sedimentation. Sequential extraction experiments show Ba being released into buffered acetic acid (carbonate fraction), aqua regia (sulfide fraction), and hydrofluoric acid (silicate fraction) extractions despite ~50% of the barium remaining undissolved as barite. Laser ablation ICP-MS showed negligible concentrations of Ba in calcite veins and elevated concentrations in areas of the shale that are predominantly clay + organics. These results suggest that some of the Ba is associated with the clay fraction of the shale (e.g., sorbed to clay surfaces as a result of the anoxic dissolution of barite). These results may inform future strategies for mitigating the release of barium into produced water.

  2. Sulfated glycans in inflammation.

    Science.gov (United States)

    Pomin, Vitor H

    2015-03-01

    Sulfated glycans such as glycosaminoglycans on proteoglycans are key players in both molecular and cellular events of inflammation. They participate in leukocyte rolling along the endothelial surface of inflamed sites; chemokine regulation and its consequential functions in leukocyte guidance, migration and activation; leukocyte transendothelial migration; and structural assembly of the subendothelial basement membrane responsible to control tissue entry of cells. Due to these and other functions, exogenous sulfated glycans of various structures and origins can be used to interventionally down-regulate inflammation processes. In this review article, discussion is given primarily on the anti-inflammatory functions of mammalian heparins, heparan sulfate, chondroitin sulfate, dermatan sulfate and related compounds as well as the holothurian fucosylated chondroitin sulfate and the brown algal fucoidans. Understanding the underlying mechanisms of action of these sulfated glycans in inflammation, helps research programs involved in developing new carbohydrate-based drugs aimed to combat acute and chronic inflammatory disorders. PMID:25576741

  3. Enterogastroesophageal reflux during barium enema: Report of a case

    International Nuclear Information System (INIS)

    Enterogastric reflux during barium enema examination has been ascribed to various causes including incompetence of the ilepcecal valve, shunt, fistula, excessive barium etc. Recently we have encountered a case of complete enterogastroesphageal regurgitation during barium enema examination performed for the reduction of the ileocolic intuosusception in 6 months old baby. The regurgitation occurred only in the first of two barium enema examinations conducted at one month interval for recurring intussusception. The barium-saline solution used in the present study was not more than 350 ml in quantity. No organic or physical causes of such a complete regurgitation could be determined

  4. Infrared Turbidimetric Titration Method for Sulfate Ions in Brackish Water

    Directory of Open Access Journals (Sweden)

    Benabadji Nouredine

    2012-12-01

    Full Text Available In this work an infrared turbidimetric titration method is described for the determination of sulfate ions in brackish water. A suspension of barium sulfate is produced in an aqueous solution and/or brackish water sample by the addition of barium chloride solution and the turbidity is monitored with the help of an immersed infrared sensor. The developed sensor utilizes an optical system to measure the evolution of turbidity during the titration. This sensor is a simple device designed in the laboratory, consisting of two infrared diodes (LED, the first is an emitter and the second is used as detector (receiver. The data acquisition system is made with the help of a dataloger made on the basis of the microcontroller 16F877/874 accompanied with adaptable software both of them are self made. Concentration over 60 µg/mL of sulfate expressed as, SO42- can be measured with high reproducibility, by this method without a preliminary treatment or dilution of the sample. The method determines SO42 - concentration of brackish water with RSD of < 1.2%.

  5. 75 FR 19657 - Barium Chloride From China

    Science.gov (United States)

    2010-04-15

    ... Commission found that the domestic interested party group response to its notice of institution (74 FR 31757... COMMISSION Barium Chloride From China AGENCY: United States International Trade Commission. ACTION: Notice of Commission determination to conduct a full five-year review concerning the antidumping duty order on...

  6. Impurities in barium titanate posistor ceramics

    Czech Academy of Sciences Publication Activity Database

    Korniyenko, S. M.; Bykov, I. P.; Glinchuk, M. J.; Laguta, V. V.; Belous, A. G.; Jastrabík, Lubomír

    2000-01-01

    Roč. 239, - (2000), s. 1209-1218. ISSN 0015-0193 Institutional research plan: CEZ:AV0Z1010914 Keywords : barium titanate phase transition * ESR * positive temperature coefficient of resistivity Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.547, year: 2000

  7. 75 FR 20625 - Barium Chloride From China

    Science.gov (United States)

    2010-04-20

    ... established a schedule for the conduct of this review (74 FR 62587, November 30, 2010). Subsequently, counsel... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Barium Chloride From China AGENCY: United States International Trade Commission. ACTION:...

  8. Thermal decomposition of barium valerate in argon

    DEFF Research Database (Denmark)

    Torres, P.; Norby, Poul; Grivel, Jean-Claude

    2015-01-01

    The thermal decomposition of barium valerate (Ba(C4H9CO2)(2)/Ba-pentanoate) was studied in argon by means of thermogravimetry, differential thermal analysis, IR-spectroscopy, X-ray diffraction and hot-stage optical microscopy. Melting takes place in two different steps, at 200 degrees C and 280...

  9. Development and Demonstration of a Sulfate Precipitation Process for Hanford Waste Tank 241-AN-107

    International Nuclear Information System (INIS)

    A series of precipitation experiments were conducted on Hanford waste tank 241-AN-107 samples in an effort to remove sulfate from the matrix. Calcium nitrate was added directly to AN-107 sub-samples to yield several combinations of Ca:CO3 mole ratios spanning a range of 0:1 to 3:1 to remove carbonate as insoluble CaCO3. Similarly barium nitrate was added directly to the AN-107 aliquots, or to the calcium pretreated AN-107 aliquots, giving of Ba:SO4 mole ratios spanning a range of 1:1 to 5:1 to precipitate sulfate as BaSO4. Initial bulk carbonate removal was required for successful follow-on barium sulfate precipitation. A ge 1:1 mole ratio of Ca:CO3 was found to lower the carbonate concentration such that Ba would react preferentially with the sulfate. A follow-on 1:1 mole ratio of Ba:SO4 resulted in 70% sulfate removal. The experiment was scaled up with a 735-mL aliquot of AN-107 for more complete testing. Calcium carbonate and barium sulfate settling rates were determined and fates of selected cations, anions, and radionuclides were followed through the various process steps. Seventy percent of the sulfate was removed in the scale-up test while recovering 63% of the filtrate volume. Surprisingly, during the scale-up test a sub-sample of the CaCO3/241-AN-107 slurry was found to lose fluidity upon standing for le 2 days. Metathesis with BaCO3 at ambient temperature was also evaluated using batch contacts at various BaCO3:SO4 mole ratios with no measurable success

  10. Study of structural, ferromagnetic and ferroelectric properties of nanostructured barium doped Bismuth Ferrite

    International Nuclear Information System (INIS)

    Nanostructured multiferroic Bi(1−x)BaxFeO3x=0.0, 0.1, 0.2 were prepared by hydrothermal technique. All samples belonged to the rhombohedrally distorted perovskite structure. The morphology of the particles changed with the doping of barium. Effect of barium doping on the dielectric constant was studied over a wide frequency range of 1000 Hz–1 MHz. The activation energy due to relaxation and due to conduction was measured from the Cole Cole plot and the AC conductivity versus frequency plot respectively. The activation energy estimated from both the studies was close to each other. The activation energy also enhanced with the increase in the barium content. The magnetization at the highest available field (∼1.6 T) increased from 0.05 emu/g for the sample with x=0.0–12 emu/g for the sample with x=0.2. The magnetic measurements show a significant increase in magnetization around 400 °C. Remnant polarization for x=0.0 was negligible and it increased to 0.06 µC/cm2 for x=0.2. - Highlights: • Bismuth Ferrite nanostructures were synthesized by the hydrothermal technique. • Barium was doped in Bismuth site. • Morphology changed with doping. • Ferromagnetic, Ferroelectric and Dielectric properties enhanced with doping. • An unreported magnetic transition due to spin canting was observed near 550 °C

  11. Characterisation of Ba(OH)(2)-Na2SO4-blast furnace slag cement-like composites for the immobilisation of sulfate bearing nuclear wastes

    OpenAIRE

    Mobasher, N.; Bernal, S. A.; Hussain, O.H.; Apperley, D.C.; Kinoshita, H.; Provis, J.L.

    2014-01-01

    Soluble sulfate ions in nuclear waste can have detrimental effects on cementitious wasteforms and disposal facilities based on Portland cement. As an alternative, Ba(OH)2–Na2SO4–blast furnace slag composites are studied for immobilisation of sulfate-bearing nuclear wastes. Calcium aluminosilicate hydrate (C–A–S–H) with some barium substitution is the main binder phase, with barium also present in the low solubility salts BaSO4 and BaCO3, along with Ba-substituted calcium sulfoaluminate hydrat...

  12. Structural and functional characterization of barium zirconium titanate / epoxy composites

    Directory of Open Access Journals (Sweden)

    Filiberto González Garcia

    2011-12-01

    Full Text Available The dielectric behavior of composite materials (barium zirconium titanate / epoxy system was analyzed as a function of ceramic concentration. Structure and morphologic behavior of the composites was investigated by X-ray Diffraction (XRD, Fourier transformed infrared spectroscopy (FT-IR, Raman spectroscopy, field emission scanning electron microscopy (FE-SEM and transmission electron microscopy (TEM analyses. Composites were prepared by mixing the components and pouring them into suitable moulds. It was demonstrated that the amount of inorganic phase affects the morphology of the presented composites. XRD revealed the presence of a single phase while Raman scattering confirmed structural transitions as a function of ceramic concentration. Changes in the ceramic concentration affected Raman modes and the distribution of particles along into in epoxy matrix. Dielectric permittivity and dielectric losses were influenced by filler concentration.

  13. Barium carbonate as an agent to improve the electrical properties of neodymium-barium-copper system at high temperature

    International Nuclear Information System (INIS)

    Specialized ceramics are manufactured under special conditions and contain specific elements. They possess unique electrical and thermal properties and are frequently used by the electronics industry. Ceramics containing neodymium-barium-copper (NBC) exhibit high conductivities at low temperatures. NBC-based ceramics are typically combined with oxides, i.e., NBCo produced from neodymium oxide, barium oxide and copper oxide. This study presents NBC ceramics that were produced with barium carbonate, copper oxide and neodymium oxide (NBCa) as starting materials. These ceramics have good electrical conductivities at room temperature. Their conductivities are temperature dependent and related to the starting amount of barium carbonate (w%). - Highlights: • The new crystalline structure were obtained due presence of the barium carbonate. • The NBCa compound has excellent electrical conductivity at room temperature. • The grain crystalline morphology was modified by presence of the barium carbonate. • New Phases α and β were introduced by carbonate barium in the NBC compound

  14. Barium carbonate as an agent to improve the electrical properties of neodymium-barium-copper system at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, J.P. [Post-Graduate Program in Chemical Engineering, Universidade Federal de Santa Catarina (UFSC), Florianópolis, SC, 88040-900 (Brazil); Duarte, G.W. [Post-Graduate Program in Chemical Engineering, Universidade Federal de Santa Catarina (UFSC), Florianópolis, SC, 88040-900 (Brazil); Research Group in Technology and Information, Centro Universitário Barriga Verde (UNIBAVE), Santa Catarina, SC (Brazil); Caldart, C. [Post-Graduate Program in Science and Materials Engineering, Universidade do Extremo Sul Catarinense (UNESC), Criciúma, SC, 88806-000 (Brazil); Kniess, C.T. [Post-Graduate Program in Professional Master in Management, Universidade Nove de Julho, São Paulo, SP (Brazil); Montedo, O.R.K.; Rocha, M.R. [Post-Graduate Program in Science and Materials Engineering, Universidade do Extremo Sul Catarinense (UNESC), Criciúma, SC, 88806-000 (Brazil); Riella, H.G. [Post-Graduate Program in Chemical Engineering, Universidade Federal de Santa Catarina (UFSC), Florianópolis, SC, 88040-900 (Brazil); Fiori, M.A., E-mail: fiori@unochapeco.edu.br [Post-Graduate Program in Environmental Science, Universidade Comunitária da Região de Chapecó (UNOCHAPECÓ), Chapecó, SC, 89809-000 (Brazil); Post-Graduate Program in Technology and Management of the Innovation, Universidade Comunitária da Região de Chapecó (UNOCHAPECÓ), Chapecó, SC, 89809-000 (Brazil)

    2015-11-15

    Specialized ceramics are manufactured under special conditions and contain specific elements. They possess unique electrical and thermal properties and are frequently used by the electronics industry. Ceramics containing neodymium-barium-copper (NBC) exhibit high conductivities at low temperatures. NBC-based ceramics are typically combined with oxides, i.e., NBCo produced from neodymium oxide, barium oxide and copper oxide. This study presents NBC ceramics that were produced with barium carbonate, copper oxide and neodymium oxide (NBCa) as starting materials. These ceramics have good electrical conductivities at room temperature. Their conductivities are temperature dependent and related to the starting amount of barium carbonate (w%). - Highlights: • The new crystalline structure were obtained due presence of the barium carbonate. • The NBCa compound has excellent electrical conductivity at room temperature. • The grain crystalline morphology was modified by presence of the barium carbonate. • New Phases α and β were introduced by carbonate barium in the NBC compound.

  15. Hybrid Nd-Fe-B/barium ferrite magnetic materials with epoxy matrix

    OpenAIRE

    Stajčić Aleksandar P.; Stajić-Trošić Jasna T.; Aleksić Radoslav R.; Žák Tomáš; Lazić Nada L.; Stijepović Mirko Z.; Grujić Aleksandar S.

    2012-01-01

    Lately a great attention has been paid to the research of bonded hybrid composites with improved dynamic mechanical capacities capable of replacing bonded Nd-Fe-B magnetic materials, by using the cheaper (ferrite) materials instead of the Nd-Fe-B powder while retaining the satisfying values of the maximal magnetic energy. The objective of this study is to assess how different contents of Nd-Fe-B and/or barium ferrite particles can affect morphological, dynamic mechanical and magnetic pr...

  16. Comparison of barium titanate thin films prepared by inkjet printing and spin coating

    OpenAIRE

    Jelena Vukmirović; Djordjije Tripković; Branimir Bajac; Sanja Kojić; Goran M. Stojanović; Vladimir V. Srdić

    2015-01-01

    In this paper, barium titanate films were prepared by different deposition techniques (spin coating, office Epson inkjet printer and commercial Dimatix inkjet printer). As inkjet technique requires special rheological properties of inks the first part of the study deals with the preparation of inks, whereas the second part examines and compares structural characteristics of the deposited films. Inks were synthesized by sol-gel method and parameters such as viscosity, particle size and surface...

  17. Human Papillomavirus Infection Requires Cell Surface Heparan Sulfate

    OpenAIRE

    Giroglou, Tzenan; Florin, Luise; Schäfer, Frank; Streeck, Rolf E.; Sapp, Martin

    2001-01-01

    Using pseudoinfection of cell lines, we demonstrate that cell surface heparan sulfate is required for infection by human papillomavirus type 16 (HPV-16) and HPV-33 pseudovirions. Pseudoinfection was inhibited by heparin but not dermatan or chondroitin sulfate, reduced by reducing the level of surface sulfation, and abolished by heparinase treatment. Carboxy-terminally deleted HPV-33 virus-like particles still bound efficiently to heparin. The kinetics of postattachment neutralization by antis...

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

    International Nuclear Information System (INIS)

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

  19. A study of the microchemistry of nanocrystalline barium titanate with tetragonal and pseudocubic room temperature symmetries

    Science.gov (United States)

    Lacey, Robert A.

    The investigation of possible effects of undesired surface species on barium titanate, one of the most utilized ferroelectric ceramics, constitutes the focus of this work. Six commercial barium titanate powders from three manufacturers representing two different synthesis processes, with average particle sizes from 40 nm to 470 nm, were analyzed in this study. Four of the nanopowders exhibited pseudocubic room temperature symmetry. Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectroscopic analysis of the nanopowders was conducted in ambient atmosphere at room temperature. High temperature DRIFT followed incorporating four avenues of analysis: moisture adsorption studies, deuterium oxide exchange studies, carbon dioxide adsorption studies, and high temperature analysis under dry air and UHP nitrogen atmospheres. At the highest temperature used in this study, 1173K, moisture and the accompanying incorporated protonic impurities were still present. The powders readily readsorbed moisture during rapid cooling, 170K/minute, to room temperature. The smallest powder, as received, formed spherical agglomerates up to 10 mum diameter. These sintered as separate units attaining diameters up to 60 mum during intermediate stage sintering. X-ray photoelectron spectroscopy indicated a surface contamination layer of 10 A to 18 A; 50--70% of which was barium carbonate, the balance being atmospheric adsorbed species. Samples cooled at 3K/minute after an 1173K calcine retained cubic symmetry as indicated with high temperature X-ray diffraction. However, spectral evidence was obtained indicating that upon the rapid cooling from the 1173K calcine, a reorientation to the room temperature tetragonal symmetry was observed. Further, SEM and TEM supported this finding with visual evidence of interfacial rearrangement including corroborating electron diffraction analysis. This data, therefore, substantiated the hypothesis that the cause of the room temperature pseudocubic

  20. Synthesis and characterization of hard magnetic composite photocatalyst-Barium ferrite/silica/titania

    International Nuclear Information System (INIS)

    Hard magnetic composite photocatalytic particles-barium ferrite (magnetic core)/silica (intermediate layer)/titania (photoactive shell) (B/S/T) were prepared by wet-chemical methods. Anatase titania nanoparticles were directly coated on the silica-coated barium ferrite forming photoactive titania shell by hydrolysis and condensation of titanium n-butoxide. The prepared hard magnetic composite photocatalyst can be magnetically fluidized and recovered by an applied magnetic field enhancing both the separation and mixing efficiency for remediating fluids. The prepared composite particles were characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution TEM (HRTEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), BET specific surface area measurement and inductively coupled plasma (ICP) spectroscopy. The photocatalytic activity of the synthesized composite particles was tested by photodegradation of Procion red MX-5B dye under UV illumination (302 nm) and compared with that of titania nanoparticles. The as-prepared composite particles were photoactive, with enhanced photocatalytic activity after the heat-treatment at 500 deg. C for 1 h. The reusability of the composite photocatalytic particles was also tested and the recycled composite particles presented the photocatalytic activity comparable to the fresh composite particles

  1. High-Jc YBCO films using precursors with barium concentration gradient in film thickness by TFA-MOD process

    International Nuclear Information System (INIS)

    YBa2Cu3O7-δ (YBCO) films were grown by using precursor films with barium concentration gradient in film thickness by an advanced metal organic deposition process using trifluoroacetates (TFA-MOD). We have reported previously that a lot of non-reacted particles such as Y- and Cu-oxides were remained for the YBCO film surface grown by the precursors using a starting solution with barium-poor (cation ratio as Y:Ba:Cu 1:1.5:3). Then, the barium concentration was increased in the film surface to complete the reaction among these Y and Cu residues and Ba and to increase the Y123 growth thickness for realizing higher Jc performance. Transmission electron microscopy (TEM) observation showed the increase of film thickness of YBCO grown by the precursors with barium concentration gradient in film thickness, indicating that the reaction between these Y and Cu-oxides and Ba proceeded to form Y123 phase. Consequently, higher Jc was obtained for the YBCO film by the precursors mentioned above than that of the YBCO film by the precursors with a constant concentration. Effects of barium concentration gradient in the precursors on the superconducting properties and microstructures in the YBCO film were discussed.

  2. Sulfate metabolism in mycobacteria.

    Science.gov (United States)

    Schelle, Michael W; Bertozzi, Carolyn R

    2006-10-01

    Pathogenic bacteria have developed numerous mechanisms to survive inside a hostile host environment. The human pathogen Mycobacterium tuberculosis (M. tb) is thought to control the human immune response with diverse biomolecules, including a variety of exotic lipids. One prevalent M. tb-specific sulfated metabolite, termed sulfolipid-1 (SL-1), has been correlated with virulence though its specific biological function is not known. Recent advances in our understanding of SL-1 biosynthesis will help elucidate the role of this curious metabolite in M. tb infection. Furthermore, the study of SL-1 has led to questions regarding the significance of sulfation in mycobacteria. Examples of sulfated metabolites as mediators of interactions between bacteria and plants suggest that sulfation is a key modulator of extracellular signaling between prokaryotes and eukaryotes. The discovery of novel sulfated metabolites in M. tb and related mycobacteria strengthens this hypothesis. Finally, mechanistic and structural data from sulfate-assimilation enzymes have revealed how M. tb controls the flux of sulfate in the cell. Mutants with defects in sulfate assimilation indicate that the fate of sulfur in M. tb is a critical survival determinant for the bacteria during infection and suggest novel targets for tuberculosis drug therapy. PMID:16933356

  3. The ceric sulfate dosimeter

    DEFF Research Database (Denmark)

    Bjergbakke, Erling

    The process employed for the determination of absorbed dose is the reduction of ceric ions to cerous ions in a solution of ceric sulfate and cerous sulfate in 0.8N sulfuric acid: Ce4+→Ce 3+ The absorbed dose is derived from the difference in ceric ion concentration before and after irradiation. The...

  4. Prospects for Barium Tagging in Gaseous Xenon

    International Nuclear Information System (INIS)

    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.

  5. Production of translationally cold barium monohalide ions

    OpenAIRE

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

    2013-01-01

    We have produced sympathetically cooled barium monohalide ions BaX$^+$ (X = F, Cl, Br) by reacting trapped, laser cooled Ba$^+$ ions with room temperature gas phase neutral halogen-containing molecules. Reaction rates for two of these (SF$_6$ and CH$_3$Cl) have been measured and are in agreement with classical models. BaX$^+$ ions are promising candidates for cooling to the rovibrational ground state, and our method presents a straightforward way to produce these polar molecular ions.

  6. Monte Carlo estimation for pediatric barium meal procedures

    International Nuclear Information System (INIS)

    Fluoroscopic barium meal (BM) series involve an X-ray examination of the esophagus, stomach, and duodenum, by the use of a contrast media – the barium sulfate (BaSO4). They are widely used to observe digestive functions or to diagnose abnormalities such as ulcers; tumors; inflammation of the esophagus, stomach, and duodenum; malrotations; vascular rings; and gastroesophageal reflux disease (a common ailment in children). However, this procedure uses long fluoroscopy times and multiple radiographies, resulting in high effective doses to pediatric patients, whose radiosensitivity and life expectancy are higher than in adults. Based on those data, the aims of the current study are to: determine the PK,A (kerma-area product) values, on the patient chest area, and the effective doses to 5 and 10 years old children. Thirty-seven different pediatric patients were studied and stratified into two group sizes: 5 and 10 years old. For each procedure, the following data was recorded: sex, age and upper chest thickness, from the patients; technical parameters of the procedure (kV, fluoroscopy time and number of radiographies); distances (focus-detector and focus-table) and field size on the examination table. Three pairs of LiF:Mg,Ti thermoluminescent dosimeters were positioned at the center of the child´s sternum. After that, upper chest thickness was subtracted from focus-table distance, so focus-patient distance was obtained. Using the field size on the table and applying similar triangles concepts, the field size on the patient was measured, which was multiplied by the mean kerma (from the dosimeters), so that PK,A could be determined. To estimate the effective dose, PK,A and technical parameters of the procedure (kV, total filtration, focus-detector distance and field size on the patient) were written in a Monte Carlo software simulation. The results of PK,A and effective doses were higher than studies used for comparison, which shows the importance of an optimization

  7. Chemical abundances and kinematics of barium stars

    CERN Document Server

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

    2016-01-01

    In this paper we present an homogeneous analysis of photospheric abundances based on high-resolution spectroscopy of a sample of 182 barium stars and candidates. We determined atmospheric parameters, spectroscopic distances, stellar masses, ages, luminosities and scale height, radial velocities, abundances of the Na, Al, $alpha$-elements, iron-peak elements, and s-process elements Y, Zr, La, Ce, and Nd. We employed the local-thermodynamic-equilibrium model atmospheres of Kurucz and the spectral analysis code {\\sc moog}. We found that the metallicities, the temperatures and the surface gravities for barium stars can not be represented by a single gaussian distribution. The abundances of $alpha$-elements and iron peak elements are similar to those of field giants with the same metallicity. Sodium presents some degree of enrichment in more evolved stars that could be attributed to the NeNa cycle. As expected, the barium stars show overabundance of the elements created by the s-process. By measuring the mean heav...

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

    Directory of Open Access Journals (Sweden)

    FarrokhTakin E

    2013-06-01

    Full Text Available Elmira FarrokhTakin,1,2 Gianni Ciofani,1 Gian Luigi Puleo,1 Giuseppe de Vito,3,4 Carlo Filippeschi,1 Barbara Mazzolai,1 Vincenzo Piazza,3 Virgilio Mattoli1 1Center for Micro-BioRobotics @SSSA, Fondazione Istituto Italiano di Tecnologia, Pontedera, Pisa, Italy; 2The Biorobotics Institute, Scuola Superiore Sant'Anna, Pontedera, Pisa, Italy; 3Center for Nanotechnology Innovation @NEST, Fondazione Istituto Italiano di Tecnologia, Pisa, Italy; 4NEST, Scuola Normale Superiore, Pisa, Italy Abstract: The development of new tools and devices to aid in treating cancer is a hot topic in biomedical research. The practice of using heat (hyperthermia to treat cancerous lesions has a long history dating back to ancient Greece. With deeper knowledge of the factors that cause cancer and the transmissive window of cells and tissues in the near-infrared region of the electromagnetic spectrum, hyperthermia applications have been able to incorporate the use of lasers. Photothermal therapy has been introduced as a selective and noninvasive treatment for cancer, in which exogenous photothermal agents are exploited to achieve the selective destruction of cancer cells. In this manuscript, we propose applications of barium titanate core–gold shell nanoparticles for hyperthermia treatment against cancer cells. We explored the effect of increasing concentrations of these nanoshells (0–100 µg/mL on human neuroblastoma SH-SY5Y cells, testing the internalization and intrinsic toxicity and validating the hyperthermic functionality of the particles through near infrared (NIR laser-induced thermoablation experiments. No significant changes were observed in cell viability up to nanoparticle concentrations of 50 µg/mL. Experiments upon stimulation with an NIR laser revealed the ability of the nanoshells to destroy human neuroblastoma cells. On the basis of these findings, barium titanate core–gold shell nanoparticles resulted in being suitable for hyperthermia treatment

  9. Lanthanide doped strontium-barium cesium halide scintillators

    Science.gov (United States)

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

    2015-06-09

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

  10. Spasmolytic effect of peppermint oil in barium during double-contrast barium enema compared with Buscopan

    Energy Technology Data Exchange (ETDEWEB)

    Asao, T.; Kuwano, H.; Ide, M.; Hirayama, I.; Nakamura, J.-I.; Fujita, K.-I.; Horiuti, R

    2003-04-01

    AIM: To evaluate the efficacy of peppermint oil in barium as a spasmolytic agent during a double-contrast barium enema (DCBE). MATERIALS AND METHODS: A total of 383 DCBEs with positive results from occult blood tests were assessed. Patients were assigned to one of four groups: peppermint in barium (n=91), peppermint in tube (n=90), Buscopan (n=105), or no treatment (n=97). After a screening sigmoidoscopy, the DCBEs were performed using air as a distending gas. In the Buscopan group, the DCBE was performed with an intramuscular injection of 20 mg Buscopan at the start of the examination. Patients in the no-treatment group underwent DCBE without any spasmolytic agent. A peppermint oil preparation (30 ml) was mixed in the barium solution for patients in the peppermint-in-barium group, and the same dose of peppermint oil was included in the enema tube in the peppermint-in-tube group. The presence of spasm on a series of spot films was evaluated without information about the type of spasmolytic agent used. RESULTS: The percentage of patients in the four groups (no treatment, Buscopan, peppermint in tube, and peppermint in barium) with absence of spasm in the entire colon on the series of spot films was 13.4, 38.1, 41.8, and 37.8%, respectively. In the group using peppermint oil or Buscopan, the rate of patients with non-spasm examination was higher than that in no-treatment group (p<0.0005). Peppermint oil had the same spasmolytic effect as the systemic administration of Buscopan in the transverse and descending colon. Peppermint oil had a stronger effect in the caecum and the ascending colon than a Buscopan injection (p<0.005). There was no advantage to placing peppermint oil in the enema tube over mixing it in the barium solution. A total of 157 polyps were found during the DCBE procedures, and no differences were observed in the number of lesions among the four groups. Peppermint oil did not impair image quality. CONCLUSION: Barium solution mixed with peppermint oil

  11. Barium hexaferrite/graphene oxide: controlled synthesis and characterization and investigation of its magnetic properties

    Science.gov (United States)

    Maddahfar, Mahnaz; Ramezani, Majid; Mostafa Hosseinpour-Mashkani, S.

    2016-08-01

    In the present study, barium hexaferrite nanocrystals (BaFe12O19) were successfully synthesized through the two-step sol-gel method in an aqueous solution in the presence of barium nitrate and iron (III) nitrate. Besides, the effect of the molar ratio of graphene oxide on the particle size and magnetic properties of final product was investigated. In this research, glucose plays a role as capping and chelating agent in the synthesis of BaFe12O19/graphene oxide. Moreover, it was found that the size, morphology, and magnetic properties of the final products could be greatly influenced by the molar ratio of graphene oxide. BaFe12O19/graphene oxide was characterized by using X-ray diffraction, scanning electron microscope, Fourier transform infrared spectroscopy, vibrating sample magnetometer, and energy-dispersive spectrometry.

  12. The evaporation residue in the fission state of Barium nuclei within relativistic mean-field theory

    CERN Document Server

    Bhuyan, M; Gupta, Raj K

    2013-01-01

    The evaporation residue of Barium isotopes are investigated in a microscopic study using relativistic mean field theory. The investigation includes the isotopes of Barium from the valley of stability to exotic proton-rich region. The ground as well as neck configurations for these nuclei are generated from their total nucleonic density distributions of the corresponding state. We have estimated the constituents (number of nucleons) in the elongated neck region of the fission state. We found the $\\alpha$-particle as the constituent of neck of Ba-isotopes, referred to as the evaporated residue in heavy-ion reaction studies. A strong correlation between the neutron and proton is observed throughout the isotopic chain.

  13. Study on the preparation and formation mechanism of barium sulphate nanoparticles modified by different organic acids

    Indian Academy of Sciences (India)

    Yuhua Shen; Chuanhao Li; Xuemei Zhu; Anjian Xie; Lingguang Qiu; Jinmiao Zhu

    2007-07-01

    This paper reports a simple method to prepare barium sulphate nanoparticles by use of tetradecanoic acid, hexadecanoic acid and stearic acid as modifier. The barium sulphate nanoparticles obtained are characterized by using Fourier transform infra-red spectroscopy (FT-IR), powder X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic laser light scatter (DLLS) and thermogravimetric analysis (TGA), respectively. The results show that the BaSO4 particles are all spherical and in the nano-scale. Our method has a better dispersion and controllable diameter dependent on the length of the chain of organic acid and the pH value of the system. A possible mechanism is also discussed.

  14. Nanocrystalline barium zirconate titanate synthesized at low temperature by an aqueous co-precipitation technique

    International Nuclear Information System (INIS)

    Single-phase nanocrystalline powder of barium zirconium titanate, Ba(Zr xTi1-x)O3 (BZT), x = 0.10, 0.20 and 0.30, was synthesized at low-temperature using an aqueous co-precipitation technique. X-ray diffraction (XRD) of the as-precipitated powder showed single-phase BZT formation. The decrease in precipitant concentration resulted in impurity barium carbonate phase formation. Transmission electron microscopy studies of as-prepared powders showed an average particle size of 30 nm and the crystallite size from XRD was estimated to be 13 nm. The microstructural studies of sintered bodies showed an average grain size of 4 μm and the dielectric and ferroelectric behaviour of BZT with 10 mol.% Zr is reported

  15. Investigation of neutron-deficient isotopes in the barium-region

    International Nuclear Information System (INIS)

    Bombarding targets of 106Cd, 108Cd and 110Cd with 16O ions of 52.5-66.0 MeV neutron deficient barium, cesium and xenon isotopes were produced and have been studied using excitation functions and neutron-gamma, proton-gamma, alpha-gamma and gamma-gamma coincidence measurements. Partial level schemes for 123Ba and 121Ba were proposed. A number of gamma transitions was assigned to the different product nuclei. The measured particle emission probabilities from the compound nuclei are compared with different evaporation models. The models mostly underestimate neutron emission and often overestimate the emission of alpha particles. (orig.)

  16. Synthesis of Barium Lithium Fluoride Nanocrystals Using Reverse Micelles as Microemulsion

    Institute of Scientific and Technical Information of China (English)

    Rui Nian HUA; De Min XIE; Chun Shan SHI

    2004-01-01

    Barium lithium fluoride nanocrystals were synthesized in cetyltrimethylammonium bromide (CTAB)/ 2-octanol/ water microemulsion systems. The impurity peaks in XRD patterns were not determined. The result of SEM confirmed that the average sizes and shape of the BaLiF3 nanocrystals. The formation of BaLiF3 and particles size were strongly affected by water content. With increasing water content and reaction times, the size of the particle increases. Meanwhile, the solvent was also found to play a key role in the synthesis of the BaLiF3 nanocrystals.

  17. Heparan sulfate biosynthesis

    DEFF Research Database (Denmark)

    Multhaupt, Hinke A B; Couchman, John R

    2012-01-01

    Heparan sulfate is perhaps the most complex polysaccharide known from animals. The basic repeating disaccharide is extensively modified by sulfation and uronic acid epimerization. Despite this, the fine structure of heparan sulfate is remarkably consistent with a particular cell type. This suggests...... apparatus has not been carried out in a detailed way using high-resolution microscopy. We have begun this process, using well-known markers for the various Golgi compartments, coupled with the use of characterized antibodies and cDNA expression. Laser scanning confocal microscopy coupled with line scanning...

  18. Holothurian Fucosylated Chondroitin Sulfate

    Directory of Open Access Journals (Sweden)

    Vitor H. Pomin

    2014-01-01

    Full Text Available Fucosylated chondroitin sulfate (FucCS is a structurally distinct glycosaminoglycan found in sea cucumber species. It has the same backbone composition of alternating 4-linked glucuronic acid and 3-linked N-acetyl galactosamine residues within disaccharide repeating units as regularly found in mammalian chondroitin sulfates. However, FucCS has also sulfated fucosyl branching units 3-O-linked to the acid residues. The sulfation patterns of these branches vary accordingly with holothurian species and account for different biological actions and responses. FucCSs may exhibit anticoagulant, antithrombotic, anti-inflammatory, anticancer, antiviral, and pro-angiogenic activities, besides its beneficial effects in hemodialysis, cellular growth modulation, fibrosis and hyperglycemia. Through an historical overview, this document covers most of the science regarding the holothurian FucCS. Both structural and medical properties of this unique GAG, investigated during the last 25 years, are systematically discussed herein.

  19. Direct Sulfation of Limestone

    DEFF Research Database (Denmark)

    Hu, Guilin; Dam-Johansen, Kim; Wedel, Stig

    2007-01-01

    %) becomes negligible. In the temperature interval from 723 K to 973 K, an apparent activation energy of about 104 kJ/mol is observed for the direct sulfation of limestone. At low temperatures and low conversions, the sulfation process is most likely under mixed control by chemical reaction and solid......The direct sulfation of limestone was studied in a laboratory fixed-bed reactor. It is found that the direct sulfation of limestone involves nucleation and crystal grain growth of the solid product (anhydrite). At 823 K and at low-conversions (less than about 0.5 %), the influences of SO2, O-2 and...... CO2 on the direct sulfation of limestone corresponds to apparent reaction orders of about 0.2, 0.2 and -0.5, respectively. Water is observed to promote the sulfation reaction and increase the apparent reaction orders of SO2 and O-2. The influence of O-2 at high O-2 concentrations (> about 15...

  20. Barium enema findings of milk allergy in infants

    International Nuclear Information System (INIS)

    We wanted to evaluate the barium enema findings of milk allergy in infants. Retrospective evaluation of the plain abdominal radiography and barium enema findings was performed in fifteen young infants suffering with milk allergy. The presence of gaseous distension, rectal gas, paralytic ileus and mechanical obstruction was evaluated on the plain radiography. The presence of spasm, a transitional zone, a reversed rectosigmoid index and mucosal irregularity was analyzed on the barium enema; the presence of barium retention was also evaluated on 24-hour-delayed plain radiography. Paralytic ileus was the most common finding on the plain radiography (93%). On the barium enema, continuous spasm of the colon, ranging from the rectum to the descending colon, was revealed in ten infants (67%). A transitional zone was observed in one infant and a reversed rectosigmoid index was revealed in four. Mucosal irregularity was observed in two infants. Barium retention was demonstrated in 11 of fifteen cases: throughout the entire colon (n = 3), from the rectum to the descending colon (n = 7), and up to the transverse colon (n = 1). The most common barium enema finding of milk allergy in infants was spasm of the distal colon. The other findings were a transitional zone, a reversed rectosigmoid index, mucosal irregularity and barium retention

  1. Synthesis of double perxenate of lanthanum and barium

    International Nuclear Information System (INIS)

    Synthesis of double perxenate of lanthanum and barium on the basis of sodium perxenate and lanthanum and barium acetates, is described. The obtained compound is characterized by means of element analysis, x-ray-electron-, IR- and RS-spectroscopy. Its thermal stability and water solubility are determined

  2. BARIUM IN TEETH AS INDICATOR OF BODY BURDEN

    Science.gov (United States)

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

  3. Colour centres in barium hexaaluminate (phase I)

    International Nuclear Information System (INIS)

    Colour centres produced by X-ray irradiation of barium hexaaluminate (phase I) with β-alumina structure are studied by electron paramagnetic resonance, optical absorption, and thermally stimulated luminescence. It is shown that in addition to the F+ centres characteristic of β-alumina phases, this compound presents other colour centres such as F, O-, and possibly V-type centres. The stability of these defects is investigated by means of thermal bleaching experiments and thermally stimulated luminescence. An alternative model to the generally accepted one is proposed, for the F+ centres, together with a mechanism of defect formation. (author)

  4. Short-cavity squeezing in barium

    Science.gov (United States)

    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.

  5. Duodenal diverticula demonstrated by barium examination

    Energy Technology Data Exchange (ETDEWEB)

    Christiansen, T.; Thommesen, P.

    An investigation for biliary tract calculi and food-stimulated gastro-oesophageal reflux was carried out in 37 patients with duodenal diverticula demonstrated by barium examination. Sixty per cent of the diverticula were located in the descending part of the duodenum. Biliary tract calculi were demonstrated in 38 per cent and food-stimulated gastro-oesophageal reflux in 81 per cent of the patients. The detection of a duodenal diverticulum should result in a supplementary investigation for gallstones and gastrooesophageal reflux and its sequelae.

  6. Barium dithionate as an EPR dosemeter.

    Science.gov (United States)

    Baran, M P; Bugay, O A; Kolesnik, S P; Maksimenko, V M; Teslenko, V V; Petrenko, T L; Desrosiers, M F

    2006-01-01

    Electron paramagnetic resonance (EPR) dosimetry is growing in popularity and this success has encouraged the search for other dosimetric materials. Previous studies of gamma-irradiated barium dithionate (BaS(2)O(6) x 2H(2)O) have shown promise for its use as a radiation dosemeter. This work studies in greater detail several essential attributes of the system. Special attention has been directed to the study of EPR response dependences on microwave power, irradiation temperature, minimum detectable dose and post-irradiation stability. PMID:16565205

  7. Scattering lengths of calcium and barium isotopes

    OpenAIRE

    Dammalapati, U.; Willmann, L.; 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 ...

  8. Influência do sulfato de bário nas características de cerâmica vermelha incorporada com resíduo oleoso inertizado Influence of barium sulfate on the characteristics of red ceramic incorporated with oily waste

    Directory of Open Access Journals (Sweden)

    F. A. N. Silva

    2006-03-01

    scanning electron microscopy (SEM. This was done to make it possible the identification of chemical elements as well as second phase particles. The results showed that the incorporation of this encapsulated petroleum waste induced changes in both, the chemical composition and the microstructure of the ceramic material.

  9. Barium cardiotoxicity: Relationship between ultrastructural damage and mechanical effects.

    Science.gov (United States)

    Delfino, G; Amerini, S; Mugelli, A

    1988-01-01

    The ultrastructural damage in guinea-pig ventricular strips caused by barium was analysed. At a concentration of 1 mmol/litre, barium chloride caused a dramatic increase in the developed tension associated with the onset of automaticity. The ultrastructural analysis demonstrated that barium caused notable and consistent alterations which affected most myocyte components. Various degenerative aspects were observed in mitochondria and in the contractile apparatus. Glycogen deposits were completely depleted. Preparations driven at 4 Hz (i.e. the rate of spontaneous firing of barium-treated preparations) showed moderate ultrastructural alterations, thus demonstrating that the increase in the rate of beating is not the only determinant of the observed damage. These results suggest that the myocardial toxicity of barium is due not only to the well-known modifications in membrane permeability, but possibly also to alterations in cell function. PMID:20702358

  10. Barium and radium migration in unconsolidated Canadian geological materials

    International Nuclear Information System (INIS)

    This report describes the results of laboratory studies on the distribution coefficients of radium and barium in samples of unconsolidated geologic materials. Graphs of Ksub(d) versus solution concentration for the respective elements showed constant Ksub(d) values in the low concentration range suggesting that, at low concentrations, a distribution coefficient is a valid means of representing the geochemical reactions of both barium and radium. The Ksub(d) values for barium range between 60 and 3500 ml/g. The values appear to be influenced by the amount of barium occurring naturally in the soil materials and thus there is little possiblility of using barium as an analog of radium in laboratory experiments. The Ksub(d) values of radium vary from 50 to 1000 ml/g indicating that a wide range of geological materials have a substantial capacity to retard the migration of radium

  11. Structure and properties of barium ferrite powders prepared by milling and annealing

    Directory of Open Access Journals (Sweden)

    J. Wron

    2007-12-01

    Full Text Available Purpose: Microstructure and magnetic properties analysis of barium ferrite powder obtained by milling and heat treatmentDesign/methodology/approach: The milling process was carried out in a vibratory mill, which generated vibrations of the balls and milled material inside the container. After milling process the powders were annealed in electric chamber furnace. The X-ray diffraction methods were used for qualitative phase analysis of studied powder samples. The morphology of Fe2O3 and BaCO3 powders after milling was analyzed using the scanning electron microscopy (SEM method. The distribution of powder particles was determined by a laser particle analyzer. The magnetic hysteresis loops of examined powder material were measured by resonance vibrating sample magnetometer (R-VSM.Findings: The milling process of iron oxide and barium carbonate mixture causes decrease of the crystallite size of involved phases and leads to increase the content of Fe2O3 phase and decrease of BaCO3 content. Milling process causes enriching of surface layer of powder particles by Fe2O3. The X-ray investigations of tested mixture milled for 30 hours and annealed at 950°C enabled the identification of hard magnetic BaFe12O19 phase and also the presence of Fe2O3 phase in examined material. The Fe2O3 phase is a rest of BaCO3 dissociation in the presence of Fe2O3, which forms a compound of BaFe12O19. The best coercive force for the mixture of powders annealed at 950°C for 10, 20 and 30 hours is 349 kA/m, 366 kA/m and 364 kA/m, respectively. From morphology images and distribution of powder particle size it can be concluded, that the size of tested powder particles increases with increasing time of milling process. The increase of milling time up to 20 hours leads to joining of smaller particles in bigger ones; agglomerates are formed.Practical implications: The barium ferrite powder obtained by milling and annealing can be suitable component to produce sintered and

  12. Preparation of precipitated barium sulphate from Egyptian barytes ore and its application in paints

    International Nuclear Information System (INIS)

    Precipitated barium sulphate (Blank fixe) was prepared and evaluated as an extender pigment, making use of the naturally occurring Egyptian barytes ore. X-ray diffraction patterns, transmission electron microscope, thermal gravimetric analysis, color measurements, specific gravity, oil absorption, bulking value, bleed resistance, hydrogen ion concentration, permanence for light and heat and chemical resistance were different methods used for characterization and evaluation of the prepared pigment. Medium oil alkyd resin, melamine-alkyd and epoxy resin were used as different binding media for the application and testing of the prepared pigments as an extender- in some paint formulations, this was done in comparison with a commercial imported blank fixe sample and the Egyptian barytes ore that it was prepared from. It was found that; a white bright fine powder of precipitated barium sulfate could be successfully prepared from the locally abundant Egyptian barytes ore. It has a suitable properties as an extender pigment. Paints pigmented with blank fixe offered favourable rheological and protective properties exceeding that of the imported commercial sample and the ore that was prepared from

  13. Radium and barium removal through blending hydraulic fracturing fluids with acid mine drainage.

    Science.gov (United States)

    Kondash, Andrew J; Warner, Nathaniel R; Lahav, Ori; Vengosh, Avner

    2014-01-21

    Wastewaters generated during hydraulic fracturing of the Marcellus Shale typically contain high concentrations of salts, naturally occurring radioactive material (NORM), and metals, such as barium, that pose environmental and public health risks upon inadequate treatment and disposal. In addition, fresh water scarcity in dry regions or during periods of drought could limit shale gas development. This paper explores the possibility of using alternative water sources and their impact on NORM levels through blending acid mine drainage (AMD) effluent with recycled hydraulic fracturing flowback fluids (HFFFs). We conducted a series of laboratory experiments in which the chemistry and NORM of different mix proportions of AMD and HFFF were examined after reacting for 48 h. The experimental data combined with geochemical modeling and X-ray diffraction analysis suggest that several ions, including sulfate, iron, barium, strontium, and a large portion of radium (60-100%), precipitated into newly formed solids composed mainly of Sr barite within the first ∼ 10 h of mixing. The results imply that blending AMD and HFFF could be an effective management practice for both remediation of the high NORM in the Marcellus HFFF wastewater and beneficial utilization of AMD that is currently contaminating waterways in northeastern U.S.A. PMID:24367969

  14. Correlation of double-contrast high-density barium enema, colonoscopy, and histology in children with special attention to disparities

    International Nuclear Information System (INIS)

    Colonscopic and double-contrast high-density barium enema (DCBE) findings were correlated in 68 patients (39 boys and 29 girls) aged 6 months to 18 years (mean 11.6 years) evaluated over a 24-month period. There was excellent correlation in 53 patients (78.0%) and good correlation in another 3 (4.4%) who had identical diagnoses and only slightly differing extent of disease reported. In 2 of these, DCBE showed more extensive disease, confirmed histologically in 1. Distal colitis seen on colonoscopy as reddening and neovascularity was missed on DCBE in 6 patients. Colonoscopy and DEBE failed to show a polyp in 1 patient each. One patient who had a normal DCBE and colonoscopy demonstrated a histological abnormality, and 1 patient with an abnormality on histology and DCBE was normal on colonscopy. A disparity resulted from the time between procedures in 1 patient and observer error in another. This high correlation is far better than any previously reported in children, supporting the use of high-density barium sulfate and double-contrast barium enemas in pediatric patients. (orig.)

  15. The Novel Formation of Barium Titanate Nanodendrites

    Directory of Open Access Journals (Sweden)

    Chien-Jung Huang

    2014-01-01

    Full Text Available The barium titanate (BaTiO3 nanoparticles with novel dendrite-like structures have been successfully fabricated via a simple coprecipitation method, the so-called BaTiO3 nanodendrites (BTNDs. This method was remarkable, fast, simple, and scalable. The growth solution is prepared by barium chloride (BaCl2, titanium tetrachloride (TiCl4, and oxalic acid. The shape and size of BaTiO3 depend on the amount of added BaCl2 solvent. To investigate the influence of amount of BaCl2 on BTNDs, the amount of BaCl2 was varied in the range from 3 to 6 mL. The role of BaCl2 is found to have remarkable influence on the morphology, crystallite size, and formation of dendrite-like structures. The thickness and length of the central stem of BTND were ~300 nm and ~20 μm, respectively. The branchings were found to occur at irregular intervals along the main stem. Besides, the formation mechanism of BTND is proposed and discussed.

  16. High resolution studies of barium Rydberg states

    International Nuclear Information System (INIS)

    The subtle structure of Rydberg states of barium with orbital angular momentum 0, 1, 2 and 3 is investigated. Some aspects of atomic theory for a configuration with two valence electrons are reviewed. The Multi Channel Quantum Defect Theory (MQDT) is concisely introduced as a convenient way to describe interactions between Rydberg series. Three high-resolution UV studies are presented. The first two, presenting results on a transition in indium and europium serve as an illustration of the frequency doubling technique. The third study is of hyperfine structure and isotope shifts in low-lying p states in Sr and Ba. An extensive study of the 6snp and 6snf Rydberg states of barium is presented with particular emphasis on the 6snf states. It is shown that the level structure cannot be fully explained with the model introduced earlier. Rather an effective two-body spin-orbit interaction has to be introduced to account for the observed splittings, illustrating that high resolution studies on Rydberg states offer an unique opportunity to determine the importance of such effects. Finally, the 6sns and 6snd series are considered. The hyperfine induced isotope shift in the simple excitation spectra to 6sns 1S0 is discussed and attention is paid to series perturbers. It is shown that level mixing parameters can easily be extracted from the experimental data. (Auth.)

  17. Coprecipitation of europium with barium sulphate

    International Nuclear Information System (INIS)

    The distribution behaviour of the trivalent europium ion at a micro-component scale, between barium sulphate and aqueous solution, was studied at ambient temperature. Experiments were carried out using radioactive tracers. Results indicate an enrichment of the micro component in the solid phase relative to the solution. The effects of the concentrations of the micro and macro-elements on the coprecipitation have been examined. Europium distribution coefficient DEu increases from 1.1 ± 0.2 to 3.2 ± 0.4 when initial europium concentration decreases from more than 17 x 10-5 to 1.4 x 10-5 M, in sulphuric media with SO42- in excess or CBa2+/CSO42- Eu. The coprecipitation of europium with barium sulphate as a heterovalent solid-solution is described by heterogeneous model obeying the Doerner and Hoskins logarithmic partition law. The weaker partition coefficients lower than unity (λ = 0.25 when CEu(III) ∼ 1.4 x 10-5 M and λ = 0.13 when CBa2+/CSO42- -5 ≤ CEu(III) = 153.5 x 10-5 M) lead to crystals increasingly enriched in the trace element. (orig.)

  18. Photon attenuation characteristics of barium enriched cement

    International Nuclear Information System (INIS)

    Nuclear radiations are widely used in several applications of nuclear sciences, medicine and industry. In the design and construction of installations housing high intensity radioactive sources and other radiation generating equipment, a variety of shielding materials are used to minimise the exposure to the individuals. Among the materials used, lead is best known for radiation shielding due to its high density and atomic number. However, in construction of radiation facilities, lead in the form of bricks or slabs cannot be substituted for cement as building material. As an alternative, barium enriched cement, which apart from better compressive strength, smoother surface finish and high abrasive resistance, offers adequate shielding to gamma radiations. In the present work, attenuation properties of commercial as well as barium enriched cements have been studied and compared with that of lead for photons of 662 and 1250 keV emitted from 137Cs and 60Co, respectively. Although photon attenuation data can be obtained by mixture rule theoretically, it is necessary to determine this data experimentally before use

  19. Mine water treatment with limestone for sulfate removal.

    Science.gov (United States)

    Silva, Adarlêne M; Lima, Rosa M F; Leão, Versiane A

    2012-06-30

    Limestone can be an option for sulfate sorption, particularly from neutral mine drainages because calcium ions on the solid surface can bind sulfate ions. This work investigated sulfate removal from mine waters through sorption on limestone. Continuous stirred-tank experiments reduced the sulfate concentration from 588.0mg/L to 87.0mg/L at a 210-min residence time. Batch equilibrium tests showed that sulfate loading on limestone can be described by the Langmuir isotherm, with a maximum loading of 23.7mg/g. Fixed-bed experiments were utilized to produce breakthrough curves at different bed depths. The Bed Depth Service Time (BDST) model was applied, and it indicated sulfate loadings of up to 20.0gSO(4)(2-)/L-bed as the flow rate increased from 1 to 10mL/min. Thomas, Yoon-Nelson and dose-response models, predicted a maximum particle loading of 19mg/g. Infrared spectrometry indicated the presence of sulfate ions on the limestone surface. Sulfate sorption on limestone seems to be an alternative to treating mine waters with sulfate concentrations below the 1200-2000mg/L range, where lime precipitation is not effective. In addition, this approach does not require alkaline pH values, as in the ettringite process. PMID:22541641

  20. Sulfate attack expansion mechanisms

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-10-15

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

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

    Science.gov (United States)

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

    1983-01-01

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

  2. Epitaxial growth and spectroscopic investigation of hexavalent manganese in barium sulfate

    OpenAIRE

    Pollnau, M.; Ehrentraut, D.; KÜck, S.

    2002-01-01

    We investigate the influence of active-ion distributions on energy-transfer upconversion (ETU) in a static upconversion regime in which energy migration is inactive and the active local environment is important for the dynamics of ETU. Neodymium is used as the probe ion. In oxide and fluoride host materials, Nd3+ possesses only one metastable excited state (4F3/2) from which strong ETU occurs. The levels excited by ETU emit weak visible luminescence, possess short (multiphonon-quenched) lifet...

  3. Designed microstructures in textured barium hexaferrite

    Science.gov (United States)

    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

  4. Intermediate milling energy optimization to enhance the characteristics of barium hexaferrite magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Hodaei, A.; Ataie, A., E-mail: aataie@ut.ac.ir; Mostafavi, E.

    2015-08-15

    Highlights: • Nano-sized BaFe{sub 12}O{sub 19} was successfully synthesized via a solid-state reaction. • Intermediate milling energy was optimized to improve BaFe{sub 12}O{sub 19} properties. • Minimum total energy of 93.7 kJ/g was necessary for formation of BaFe{sub 12}O{sub 19}. • Deviation from the optimum milling energy deteriorates the magnetic properties. - Abstract: Nano-sized barium hexaferrite particles were synthesized by mechanical activation of BaCO{sub 3} and Fe{sub 2}O{sub 3} powders mixture as starting materials. The effects of mechanical milling energy on the phase composition, morphology, thermal behavior and magnetic properties of the samples were systematically investigated by employing X-ray diffractometer, field emission scanning electron microscopy, differential thermal/thermo gravimetry analysis and vibrating sample magnetometer, respectively. The milling energy was calculated at five different levels using collision model. It was found that there is an optimum milling energy value for obtaining barium hexaferrite phase. The results revealed that applying a minimum total milling energy of 93.7 kJ/g was necessary for formation of almost single barium hexaferrite at a relatively low calcination temperature of 800 °C. FESEM micrograph of the above sample exhibited nano-size particles with a mean particle size of 80 nm. Further increase in milling energy leads to dramatic decrease in phase purity as well as magnetic characteristics of the samples. By increasing the milling energy from 93.7 to 671.9 kJ/g, saturation magnetization (M{sub s}) decreased from 22.5 to 0.39 emu/g, and also coercivity (H{sub c}) decreased from 4.28 to 1.46 kOe.

  5. Intermediate milling energy optimization to enhance the characteristics of barium hexaferrite magnetic nanoparticles

    International Nuclear Information System (INIS)

    Highlights: • Nano-sized BaFe12O19 was successfully synthesized via a solid-state reaction. • Intermediate milling energy was optimized to improve BaFe12O19 properties. • Minimum total energy of 93.7 kJ/g was necessary for formation of BaFe12O19. • Deviation from the optimum milling energy deteriorates the magnetic properties. - Abstract: Nano-sized barium hexaferrite particles were synthesized by mechanical activation of BaCO3 and Fe2O3 powders mixture as starting materials. The effects of mechanical milling energy on the phase composition, morphology, thermal behavior and magnetic properties of the samples were systematically investigated by employing X-ray diffractometer, field emission scanning electron microscopy, differential thermal/thermo gravimetry analysis and vibrating sample magnetometer, respectively. The milling energy was calculated at five different levels using collision model. It was found that there is an optimum milling energy value for obtaining barium hexaferrite phase. The results revealed that applying a minimum total milling energy of 93.7 kJ/g was necessary for formation of almost single barium hexaferrite at a relatively low calcination temperature of 800 °C. FESEM micrograph of the above sample exhibited nano-size particles with a mean particle size of 80 nm. Further increase in milling energy leads to dramatic decrease in phase purity as well as magnetic characteristics of the samples. By increasing the milling energy from 93.7 to 671.9 kJ/g, saturation magnetization (Ms) decreased from 22.5 to 0.39 emu/g, and also coercivity (Hc) decreased from 4.28 to 1.46 kOe

  6. On-line ultrasonic characterisation of barium doped lanthanum perovskites

    International Nuclear Information System (INIS)

    Perovskite manganite samples La1−xBaxMnO3 with the composition of x=0.30, 0.33 and 0.36 were prepared by employing solid state reaction technique. The X-ray diffraction (XRD) patterns confirmed the rhombhedral structure with R3c space group of the samples. The obtained energy dispersive analysis X-rays (EDX) spectra of the samples have confirmed the elemental composition of the samples. The scanning electron microscope (SEM) images of the samples were used to find out the size of the particles. In-situ ultrasonic measurements were carried out on the samples by through transmission method. The temperature dependence of the ultrasonic parameters revealed interesting features of the samples. The observed ultrasonic velocities and attenuation both in longitudinal and shear mode are related to the paramagnetic (PM) to ferromagnetic (FM) phase transition in the prepared samples. The results confirmed that an increase in the barium content in the sample leads to an increase in the phase transition temperature TC

  7. Removal of uranyl ions from aqueous solutions using barium titanate

    International Nuclear Information System (INIS)

    Remediation of water sources contaminated with radioactive waste products is a major environmental issue that demands new and more efficient technologies. For this purpose, we report a highly efficient ion-exchange material for the removal of radioactive nuclides from aqueous solutions. The kinetic characteristics of adsorption of uranyl ions on the surface of barium titanate were investigated using a spectrophotometric method under a wide range of conditions. By controlling the pH it was possible to exert fine control over the speciation of uranium, and by optimizing the temperature and grain size of the exchanger, almost total removal was achieved in a matter of just hours. The highest efficiency (>90 % removal) was realized at high temperature (80 deg C). Moreover, the effect of competitive ion adsorption from a range of different cations and anions was quantified. Adsorption was found to follow first-order kinetics and both Freundlich and Langmuir isotherms could be applied to this system. The results of a mathematical treatment of the kinetic data combined with the observation that adsorption was independent of stirring speed and dependent on the ion-exchanger grain size, indicate that the dominant mechanism influencing adsorption is particle spreading. The adsorption behavior was not influenced by exposure to high-intensity gamma radiation, indicating potential for use of this ion-exchanger in systems containing radioactive material. These results will be of use in the development of uranium extraction systems for contaminated water sources. (author)

  8. On-line ultrasonic characterisation of barium doped lanthanum perovskites

    Energy Technology Data Exchange (ETDEWEB)

    Thamilmaran, P.; Arunachalam, M. [Department of Physics, Sri SRNM College, Sattur 626203, Tamil Nadu (India); Research scholars in Physics, Manonmanium Sundaranar University, Tirunelveli 627012 Tamil Nadu (India); Sankarrajan, S. [Department of Physics, Unnamalai Institute of Technology, Kovilpatti 628503, Tamil Nadu (India); Sakthipandi, K., E-mail: sakthipandi@gmail.com [Department of Physics, Sethu Institute of Technology, Kariapatti 626115, Tamil Nadu (India)

    2015-06-15

    Perovskite manganite samples La{sub 1−x}Ba{sub x}MnO{sub 3} with the composition of x=0.30, 0.33 and 0.36 were prepared by employing solid state reaction technique. The X-ray diffraction (XRD) patterns confirmed the rhombhedral structure with R3c space group of the samples. The obtained energy dispersive analysis X-rays (EDX) spectra of the samples have confirmed the elemental composition of the samples. The scanning electron microscope (SEM) images of the samples were used to find out the size of the particles. In-situ ultrasonic measurements were carried out on the samples by through transmission method. The temperature dependence of the ultrasonic parameters revealed interesting features of the samples. The observed ultrasonic velocities and attenuation both in longitudinal and shear mode are related to the paramagnetic (PM) to ferromagnetic (FM) phase transition in the prepared samples. The results confirmed that an increase in the barium content in the sample leads to an increase in the phase transition temperature T{sub C}.

  9. Chemical composition of Eu2+ luminescence in the barium hexaaluminates

    International Nuclear Information System (INIS)

    This paper consists of two parts. In the first part the chemical composition of two kinds of barium hexaaluminate (one poor and one rich in barium) is explained using the local electroneutrality concept. In the second part a reinvestigation of the Eu2+ luminescence in these compounds is reported. The emission spectrum of each of the two compounds shows a blue and a green emission bank. The blue emission bank is ascribed to Eu2+ ions at barium sites, whereas the green emission band is identified with Eu2+ ions incorporated at aluminum sites within spinel blocks of the structure

  10. Magic Wavelength of an Optical Clock Transition of Barium

    International Nuclear Information System (INIS)

    Similar to most of the other alkaline earth elements, barium atoms can be candidates for optical clocks, thus the magic wavelength for an optical lattice is important for the clock transition. We calculate the magic wavelength of a possible clock transition between 6s21S0 and 6s5d3 D2 states of barium atoms. Our theoretical result shows that there are three magic wavelengths 615.9nm, 641.2nm and 678.8nm for a linearly polarized optical lattice laser for barium. (atomic and molecular physics)

  11. Low temperature preparation of nanocrystalline solid solution of strontium barium niobate by chemical process

    Indian Academy of Sciences (India)

    Asit B Panda; Amita Pathak; Panchanan Pramanik

    2002-11-01

    SrBa1–Nb2O6 (with = 0.4, 0.5 and 0.6) powders have been prepared by thermolysis of aqueous precursor solutions consisting of triethanolamine (TEA), niobium tartarate and, EDTA complexes of strontium and barium ions. Complete evaporation of the precursor solution by heating at ∼ 200°C, yields in a fluffy, mesoporous carbon rich precursor material, which on calcination at 750°C/2 h has resulted in the pure SBN powders. The crystallite and average particle sizes are found to be around 15 nm and 20 nm, respectively.

  12. Comparison of barium titanate thin films prepared by inkjet printing and spin coating

    Directory of Open Access Journals (Sweden)

    Jelena Vukmirović

    2015-09-01

    Full Text Available In this paper, barium titanate films were prepared by different deposition techniques (spin coating, office Epson inkjet printer and commercial Dimatix inkjet printer. As inkjet technique requires special rheological properties of inks the first part of the study deals with the preparation of inks, whereas the second part examines and compares structural characteristics of the deposited films. Inks were synthesized by sol-gel method and parameters such as viscosity, particle size and surface tension were measured. Deposited films were examined by optical and scanning electron microscopy, XRD analysis and Raman spectroscopy. The findings consider advantages and disadvantages of the particular deposition techniques.

  13. A novel barium polymeric membrane sensor for selective determination of barium and sulphate ions based on the complex ion associate barium(II)-Rose Bengal as neutral ionophore

    Energy Technology Data Exchange (ETDEWEB)

    Othman, A.M. [Genetic Engineering and Biotechnology Research Institute (GEBRI), Minufiya University, Sadat City (Egypt); El-Shahawi, M.S. [Chemistry Department, Faculty of Science at Damiatta, Mansoura University, Damiatta, Dumyat 34517 (Egypt)]. E-mail: mohammad_el_shahawi@yahoo.co.uk; Abdel-Azeem, M. [Chemistry Department, Faculty of Science at Damiatta, Mansoura University, Damiatta, Dumyat 34517 (Egypt)

    2006-01-12

    A simple, long life, rapid response and sensitive barium(II)-PVC membrane sensor that typically follows Nernstian behavior has been developed for the assay of barium(II) ions. The developed sensor has been made by incorporating the complex ion associate of barium(II)-Rose Bengal (Ba-RB) as an ionophore into a plasticized PVC matrix. The sensor is stable and exhibited fast potential response of 20 s and gave a good linear response with a Nernstian slope of 28.5 {+-} 0.4 mV/decade of activity within the concentration range 5 x 10{sup -5} to 10{sup -1} M over a wide range of pH 4.5-10.0 for barium(II) ions. The developed sensor showed comparatively good selectivity for barium(II) ions with respect to other alkali, alkaline earth, transition and heavy metal ions. The plasticizer o-nitrophenyloctyl ether controlled significantly the calibration slope and the lifetime of the fabricated sensor. The proposed sensor was used successfully for the analysis of barium(II) ions in wastewater samples and in lithophone pigment with excellent recovery percentages in the range 98.9-99.8 {+-} 1.6%. The determination of sulphate in fresh and potable water samples with the developed sensor has been also achieved successfully. The described sensor provides a reliable means with good correlation with the data obtained by atomic absorption spectrometry (AAS) and other spectrophotometric methods for the analysis of trace amounts of barium(II) and/or sulphate ions in different matrices.

  14. A novel barium polymeric membrane sensor for selective determination of barium and sulphate ions based on the complex ion associate barium(II)-Rose Bengal as neutral ionophore

    International Nuclear Information System (INIS)

    A simple, long life, rapid response and sensitive barium(II)-PVC membrane sensor that typically follows Nernstian behavior has been developed for the assay of barium(II) ions. The developed sensor has been made by incorporating the complex ion associate of barium(II)-Rose Bengal (Ba-RB) as an ionophore into a plasticized PVC matrix. The sensor is stable and exhibited fast potential response of 20 s and gave a good linear response with a Nernstian slope of 28.5 ± 0.4 mV/decade of activity within the concentration range 5 x 10-5 to 10-1 M over a wide range of pH 4.5-10.0 for barium(II) ions. The developed sensor showed comparatively good selectivity for barium(II) ions with respect to other alkali, alkaline earth, transition and heavy metal ions. The plasticizer o-nitrophenyloctyl ether controlled significantly the calibration slope and the lifetime of the fabricated sensor. The proposed sensor was used successfully for the analysis of barium(II) ions in wastewater samples and in lithophone pigment with excellent recovery percentages in the range 98.9-99.8 ± 1.6%. The determination of sulphate in fresh and potable water samples with the developed sensor has been also achieved successfully. The described sensor provides a reliable means with good correlation with the data obtained by atomic absorption spectrometry (AAS) and other spectrophotometric methods for the analysis of trace amounts of barium(II) and/or sulphate ions in different matrices

  15. Theoretical isotope shifts in neutral barium

    CERN Document Server

    Nazé, Cédric; Godefroid, Michel

    2015-01-01

    The present work deals with a set of problems in isotope shifts of neutral barium spectral lines. Some well known transitions ($6s^2~^1S_0-6s6p~^{1,3}P^o_1$ and $6s^2~^1S_0-6p^2~^3P_0$) are first investigated. Values of the changes in the nuclear mean-square charge radius are deduced from the available experimental isotope shifts using our ab initio electronic factors. The three sets $\\{ \\delta\\langle r^2\\rangle^{A,A'}\\} $ obtained from these lines are consistent with each other. The combination of the available nuclear mean-square radii with our electronic factors for the $6s5d~^3D_{1,2} -6s6p~^{1}P^o_1$ transitions produces isotope shift values in conflict with the laser spectroscopy measurements of Dammalapati et al. (Eur. Phys. J. D 53, 1 (2009)).

  16. Chemical abundance analysis of 19 barium stars

    CERN Document Server

    Yang, G C; Spite, M; Chen, Y Q; Zhao, G; Zhang, B; Liu, G Q; Liu, Y J; Liu, N; Deng, L C; Spite, F; Hill, V; Zhang, C X

    2016-01-01

    We aim at deriving accurate atmospheric parameters and chemical abundances of 19 barium (Ba) stars, including both strong and mild Ba stars, based on the high signal-to-noise ratio and high resolution Echelle spectra obtained from the 2.16 m telescope at Xinglong station of National Astronomical Observatories, Chinese Academy of Sciences. The chemical abundances of the sample stars were obtained from an LTE, plane-parallel and line-blanketed atmospheric model by inputting the atmospheric parameters (effective temperatures, surface gravities, metallicity and microturbulent velocity) and equivalent widths of stellar absorption lines. These samples of Ba stars are giants indicated by atmospheric parameters, metallicities and kinematic analysis about UVW velocity. Chemical abundances of 17 elements were obtained for these Ba stars. Their light elements (O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn and Ni) are similar to the solar abundances. Our samples of Ba stars show obvious overabundances of neutron-capture (n-ca...

  17. Analysis of europium doped luminescent barium thioaluminate

    Institute of Scientific and Technical Information of China (English)

    张东璞; 喻志农; 薛唯; 章婷; 丁瞾; 王武育

    2010-01-01

    Europium-doped barium thioaluminate sputtering target was synthesized by powder sintering method and thin film was deposited by radio frequency(RF) sputtering.X-ray diffractometer(XRD) pattern indicated that the main compound of the target was BaAl4S7.Oxygen was the main impurity which led to the formation of BaAl2O4.It was shown that both BaAl4S7 and BaAl2S4 were contained in the as-grown thin films and a 471.7 nm emission peak in the PL spectra appeared due to a combination of BaAl4S7:Eu2+ and BaAl2S4:Eu2...

  18. Crystal structure of tris­(piperidinium) hydrogen sulfate sulfate

    OpenAIRE

    Lukianova, Tamara J.; Kinzhybalo, Vasyl; Pietraszko, Adam

    2015-01-01

    A novel mixed hydrogen sulfate–sulfate piperidinium salt comprises three protonated piperidinium cations, one hydrogen sulfate anion and one sulfate anion in the asymmetric unit. Strong hydrogen bonds exist between the cations and the anions giving rise to a three-dimensional structure.

  19. Radar absorption properties of doped barium hexaferrite

    International Nuclear Information System (INIS)

    Full text: Since the 1950s, it has been known that barium hexaferrite exhibits a ferrimagnetic resonance at about 48 GHz. Early research was directed at finding dopants that would increase this frequency to enable the preparation of lossless waveguide components. However, more recent efforts have explored the potential of doped barium hexaferrite as a radar absorbing material in the low GHz frequency range. In particular, Nedkov et al demonstrated that partial substitution of the iron with cobalt-titanium, to give Ba(Co0.5Ti0.5)xFe11.9-xMn0.1O19 with x = 1.6, could reduce the ferrimagnetic resonance frequency to 15 GHz. The small amount of manganese was included 'to improve the dielectric properties' of the material. In this work we increased the doping to x = 2.2 to arrive at a resonance frequency of just 1.35 GHz, which lies within the operational frequency range of typical airborne early warning and control (AEWAC) radar systems. An increase in the resonance signal at this concentration is believed to be associated with the onset of a switch from axial to planar magnetocrystalline anisotropy, as reported by Kreisel et al . It is uncertain why our resonance frequency for x = 2.2 is significantly lower than the value of 2.56 GHz reported elsewhere for a Mn-free specimen with x = 2.6. Chromium was also tested as a new dopant material but proved unsuccessful in reducing the resonant frequency below 40 GHz, the upper limit of the microwave network analyser that was employed. All specimens were prepared using solid state reaction of stoichiometric amounts of oxides and carbonates, and characterised using x-ray powder diffraction and 57Fe Moessbauer spectroscopy

  20. The Karlsruhe 4π barium fluoride detector

    International Nuclear Information System (INIS)

    A new experimental approach has been implemented for accurate measurements of neutron capture cross sections in the energy range from 5 to 200 keV. The Karlsruhe 4π Barium Fluoride Detector consists of 42 crystals shaped as hexagonal and pentagonal truncated pyramids forming a spherical shell with 10 cm inner radius and 15 cm thickness. All crystals are supplied with reflector and photomultiplier, thus representing independent gamma-ray detectors. Each detector module covers the same solid angle with respect to a gamma-ray source located in the centre. The energy resolution of the 4π detector is 14% at 662 keV and 7% at 2.5 MeV gamma-ray energy, the overall time reslution is 500 ps and the peak efficiency 90% at 1 MeV. The detector allows to register capture cascades with 95% probability above a threshold energy of 2.5 MeV in the sum energy spectrum. Neutrons are produced via the 7Li(p,n)7Be reaction using the pulsed proton beam of a Van de Graaff accelerator. The neutron spectrum can be taylored according to the experimental requirements in an energy range from 5 to 200 keV by choosing appropriate proton energies. A collimated neutron beam is passing through the detector and hits the sample in the centre. The energy of captured neutrons is determined via time of flight, the primary flight path being 77 cm. The combination of short primary flight path, a 10 cm inner radius of the spherical BaF2 shell, and the low capture cross section of barium allows to discriminate background due to capture of sample scattered neutrons in the scintillator by time of flight, leaving part of the neutron energy range completely undisturbed. (orig./HSI)

  1. Hydrazine Sulfate (PDQ)

    Science.gov (United States)

    ... use of hydrazine sulfate as a complementary or alternative treatment for cancer? It has been known since the early 1900s ... of CAM therapies originally considered to be purely alternative approaches are finding a place in cancer treatment—not as cures, but as complementary therapies that ...

  2. Aluminum Sulfate 18 Hydrate

    Science.gov (United States)

    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.

  3. FY-15 Progress Report on Cleanup of irradiated SHINE Target Solutions Containing 140g-U/L Uranyl Sulfate

    International Nuclear Information System (INIS)

    During FY 2012 and 2013, a process was developed to convert the SHINE Target Solution (STS) of irradiated uranyl sulfate (140 g U/L) to uranyl nitrate. This process is necessary so that the uranium solution can be processed by the UREX (Uranium Extraction) separation process, which will remove impurities from the uranium so that it can be recycled. The uranyl sulfate solution must contain <0.02 M SO42- so that the uranium will be extractable into the UREXsolvent. In addition, it is desired that the barium content be below 0.0007 M, as this is the limit in the Resource Conservation and Recovery Act (RCRA).

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

    International Nuclear Information System (INIS)

    Sulfur is the major component of polluted air in industrialized societies. Atmospheric sulfur is converted to sulfuric acid through a series of chemical reactions which can eventually reenter many ecosystems. When edible plants are grown in soils containing varying amounts of sulfate, the roots take up and transport inorganic sulfate to the stems and leaves. The sulfate taken up by the roots and the amount transported to the stem and leaves was found to be a function of the concentration of sulfate in the soil. Inorganic sulfate taken up by a corn plant seedling can be rapidly converted to organic sulfate by the root system. Nine days after one of a pair of pea plants was inoculated with artificial acid rain sulfate (dilute H235SO4) it was found that the sulfate was translocated not only in the inoculated plant, but also to the uninoculated pea plant in the same container. Also, when the leaves of a mature potato plant were inoculated with artificial acid rain sulfate it was found that the sulfate was translocated into the edible potatoes. Fractionation of the potatoes showed that most of the sulfate was water soluble of which 30% was inorganic sulfate and 70% was in the form of organic sulfur. One third of the non-water soluble translocated acid rain sulfate was equally divided between lipid and non-lipid organic sulfur of the potato. 9 references, 2 figures, 5 tables

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

    Institute of Scientific and Technical Information of China (English)

    Pankaj; Gupta; Uma; Debi; Saroj; Kant; Sinha; 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.

  6. Liquid-phase-deposited barium titanate thin films on silicon

    International Nuclear Information System (INIS)

    Using a mixture of hexafluorotitanic acid, barium nitrate and boric acid, high refractive index (1.54) barium titanate films can be deposited on silicon substrates. The deposited barium titanate films have featureless surfaces. The deposition temperature is near room temperature (800C). However, there are many fluorine and silicon incorporations in the films. The refractive index of the as-deposited film is 1.54. By current-voltage measurement, the leakage current of the as-deposited film with a thickness of 1000 A is about 9.48x10-7 A cm-2 at the electrical field intensity of 0.3 MV cm-1. By capacitance-voltage measurement, the effective oxide charge of the liquid-phase-deposited barium titanate film is 3.06x1011 cm-2 and the static dielectric constant is about 22. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jing [Department of Applied Physics, Chongqing University, 174 Shapingba Street, Chongqing 400044 (China); Chongqing University of Science and Technology, Chongqing 401331 (China); Hu, Chenguo, E-mail: hucg@cqu.edu.cn [Department of Applied Physics, Chongqing University, 174 Shapingba Street, Chongqing 400044 (China); Xi, Yi [Department of Applied Physics, Chongqing University, 174 Shapingba Street, Chongqing 400044 (China); Peng, Chen [School of Physical Science and Technology, Southwest University, Chongqing 400715 (China); Wan, Buyong; He, Xiaoshan [Department of Applied Physics, Chongqing University, 174 Shapingba Street, Chongqing 400044 (China)

    2011-06-15

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

  8. Hydrothermal Synthesis and Processing of Barium Titanate Nanoparticles Embedded in Polymer Films.

    Science.gov (United States)

    Toomey, Michael D; Gao, Kai; Mendis, Gamini P; Slamovich, Elliott B; Howarter, John A

    2015-12-30

    Barium titanate nanoparticles embedded in flexible polymer films were synthesized using hydrothermal processing methods. The resulting films were characterized with respect to material composition, size distribution of nanoparticles, and spatial location of particles within the polymer film. Synthesis conditions were varied based on the mechanical properties of the polymer films, ratio of polymer to barium titanate precursors, and length of aging time between initial formulations of the solution to final processing of nanoparticles. Block copolymers of poly(styrene-co-maleic anhydride) (SMAh) were used to spatially separate titanium precursors based on specific chemical interactions with the maleic anhydride moiety. However, the glassy nature of this copolymer restricted mobility of the titanium precursors during hydrothermal processing. The addition of rubbery butadiene moieties, through mixing of the SMAh with poly(styrene-butadiene-styrene) (SBS) copolymer, increased the nanoparticle dispersion as a result of greater diffusivity of the titanium precursor via higher mobility of the polymer matrix. Additionally, an aminosilane was used as a means to retard cross-linking in polymer-metalorganic solutions, as the titanium precursor molecules were shown to react and form networks prior to hydrothermal processing. By adding small amounts of competing aminosilane, excessive cross-linking was prevented without significantly impacting the quality and composition of the final barium titanate nanoparticles. X-ray diffraction and X-ray photoelectron spectroscopy were used to verify nanoparticle compositions. Particle sizes within the polymer films were measured to be 108 ± 5 nm, 100 ± 6 nm, and 60 ± 5 nm under different synthetic conditions using electron microscopy. Flexibility of the films was assessed through measurement of the glass transition temperature using dynamic mechanical analysis. Dielectric permittivity was measured using an impedance analyzer. PMID

  9. Lifetime Measurement for 6snp Rydberg States of Barium

    Institute of Scientific and Technical Information of China (English)

    SHEN Li; WANG Lei; YANG Hai-Feng; LIU Xiao-Jun; LIU Hong-Ping

    2011-01-01

    @@ We present a simple and efficient method for measuring the atomic lifetimes in order of tens of microseconds and demonstrate it in the lifetime determination of barium Rydberg states.This method extracts the lifetime information from the time-of-flight spectrum directly, which is much more efficient than other methods such as the time-delayed field ionization and the traditional laser induced fluorescence.The lifetimes determined with our method for barium Rydberg 6snp(n=37-59)series are well coincident with the values deduced from the absolute oscillator strengths of barium which were given in the literature [J.Phys.B 14(1981)4489, 29(1996)655]on experiments.%We present a simple and efficient method for measuring the atomic lifetimes in order of tens of microseconds and demonstrate it in the lifetime determination of barium Rydberg states. This method extracts the lifetime information from the time-of-flight spectrum directly, which is much more efficient than other methods such as the time-delayed field ionization and the traditional laser induced fluorescence. The lifetimes determined with our method for barium Rydberg 6snp (n=37-59) series are well coincident with the values deduced from the absolute oscillator strengths of barium which were given in the literature [J. Phys. B 14 (1981) 4489, 29 (1996) 655] onexperiments.

  10. Effect of additive particles on mechanical, thermal, and cell functioning properties of poly(methyl methacrylate cement

    Directory of Open Access Journals (Sweden)

    Khandaker M

    2014-05-01

    Full Text Available Morshed Khandaker,1 Melville B Vaughan,2 Tracy L Morris,3 Jeremiah J White,1 Zhaotong Meng1 1Department of Engineering and Physics, 2Department of Biology, 3Department of Mathematics and Statistics, University of Central Oklahoma, Edmond, OK, USA Abstract: The most common bone cement material used clinically today for orthopedic surgery is poly(methyl methacrylate (PMMA. Conventional PMMA bone cement has several mechanical, thermal, and biological disadvantages. To overcome these problems, researchers have investigated combinations of PMMA bone cement and several bioactive particles (micrometers to nanometers in size, such as magnesium oxide, hydroxyapatite, chitosan, barium sulfate, and silica. A study comparing the effect of these individual additives on the mechanical, thermal, and cell functional properties of PMMA would be important to enable selection of suitable additives and design improved PMMA cement for orthopedic applications. Therefore, the goal of this study was to determine the effect of inclusion of magnesium oxide, hydroxyapatite, chitosan, barium sulfate, and silica additives in PMMA on the mechanical, thermal, and cell functional performance of PMMA. American Society for Testing and Materials standard three-point bend flexural and fracture tests were conducted to determine the flexural strength, flexural modulus, and fracture toughness of the different PMMA samples. A custom-made temperature measurement system was used to determine maximum curing temperature and the time needed for each PMMA sample to reach its maximum curing temperature. Osteoblast adhesion and proliferation experiments were performed to determine cell viability using the different PMMA cements. We found that flexural strength and fracture toughness were significantly greater for PMMA specimens that incorporated silica than for the other specimens. All additives prolonged the time taken to reach maximum curing temperature and significantly improved cell

  11. Validation of an in situ solidification/stabilization technique for hazardous barium and cyanide waste for safe disposal into a secured landfill.

    Science.gov (United States)

    Vaidya, Rucha; Kodam, Kisan; Ghole, Vikram; Surya Mohan Rao, K

    2010-09-01

    The aim of the present study was to devise and validate an appropriate treatment process for disposal of hazardous barium and cyanide waste into a landfill at a Common Hazardous Waste Treatment Storage Disposal Facility (CHWTSDF). The waste was generated during the process of hardening of steel components and contains cyanide (reactive) and barium (toxic) as major contaminants. In the present study chemical fixation of the contaminants was carried out. The cyanide was treated by alkali chlorination with calcium hypochlorite and barium by precipitation with sodium sulfate as barium sulfate. The pretreated mixture was then solidified and stabilized by binding with a combination of slag cement, ordinary Portland cement and fly ash, molded into blocks (5 x 5 x 5 cm) and cured for a period of 3, 7 and 28 days. The final experiments were conducted with 18 recipe mixtures of waste + additive:binder (W:B) ratios. The W:B ratios were taken as 80:20, 70:30 and 50:50. The optimum proportions of additives and binders were finalized on the basis of the criteria of unconfined compressive strength and leachability. The leachability studies were conducted using the Toxicity Characteristic Leaching Procedure. The blocks were analyzed for various physical and leachable chemical parameters at the end of each curing period. Based on the results of the analysis, two recipe mixtures, with compositions - 50% of [waste + (120 g Ca(OCl)(2) + 290 g Na(2)SO(4)) kg(-1) of waste] + 50% of binders, were validated for in situ stabilization into a secured landfill of CHWTSDF. PMID:20430516

  12. Radioimmunoassay of dehydroepiandrosterone sulfate

    International Nuclear Information System (INIS)

    The development of a radioimmunological method for the measurement of dehydroepiandrosterone sulfate in serum is described. For the immunization of rabbits, a DHA-3-hemissuccinate-bovine serum albumin conjugate was synthetized and a highly specific anti-serum was produced. The method developed requires only simple dilution prior to assay and the normal values for the different age groups were determined in 146 normal individuals. (Author)

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

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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 = 230C. 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

  15. Optical properties of calcium barium niobate

    International Nuclear Information System (INIS)

    We report on optical measurements on the novel tungsten bronze type calcium barium niobate. [001]-oriented transparent and colorless single crystals were grown by the Czochralski method with dimensions of 12 mm in diameter and about 80 mm in length. With its relatively high Curie temperature of about 538 K for the congruently melting composition of 28.1 mole% calcium and its high nonlinear coefficients, CBN is a promising material for future applications. Recent experiments revealed, that the application of an external electric field of several kV/cm to CBN at room temperature leads to an increasing opacity of the sample. This might be a drawback considering the future usability of CBN in optical systems. We present investigations on the transmittance behaviour of CBN under external electric fields, demonstrating the erasement of the clouding without affecting the polarization. Experiments have been performed at temperatures ranging from room temperature to approximately 480 K. When heating up the sample, its colorless appearance changes to a light yellow, which can be attributed to a shift of the band edge to longer wavelengths with increasing temperature. To further investigate the transmittance properties of CBN, measurements of the band edge under various temperatures up to the ferroelectric phase transition have been performed.

  16. Leachability of barium-radium sulphate sludges

    International Nuclear Information System (INIS)

    This paper presents results from the first phase of a research program designed to examine the leachability of radium-226 from barium-radium sulphate sludges. Batch leaching tests were performed. Results showed that liquid:solid contact time was relatively unimportant; radium in the sludge was stable in the presence of deionized water with a slight increase in the amount leached per gram of sludge occurring at higher liquid:solid ratios. Not unexpectedly, low and high values of leachant pH increased radium leaching. Both monovalent and divalent salt solutions also increased leaching; however, dissolved radium-226 activity levels in the leachate decreased as leachant molarity increased. For divalent salts this can be explained by the common ion effect; for monovalent salts it is opposite to results expected from solubility considerations. The interpretation of all results is complicated by the fact that in most tests, the amount of radium-226 present in the leachate was lower than the calculated contribution from the mother liquour present with the sludge. This apparent ability of the sludge to absorb radium from solution may be related to dissolution and reprecipitation of the sludge during the leaching tests

  17. Chemical compositions of four barium stars

    CERN Document Server

    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...

  18. The diagnostic value of barium enema in acute appendicitis

    International Nuclear Information System (INIS)

    Acute appendicitis is the most common acute surgical condition of the abdomen. When the clinical presentation is atypical, barium enema has proven to be safe and useful in confirming the diagnosis and reducing the negative surgical exploration. However, the performance of barium enema in acute appendicitis has known contraindication primarily because of fear of leakage by perforation of the inflamed appendix. This study using barium enema as a diagnostic aid in acute appendicitis with atypical clinical presentation was performed to further support the previously noted efficacy and safety of this procedure. The results were as followings: 1. In case of acute appendicitis with atypical clinical presentation, the use of barium enema as a diagnostic aid increased the accuracy of diagnosis and decreased the negative surgical exploration. In women between 11 to 50 years old age, especially, it played important role differentiating appendicitis from nonsurgical acute abdomen. 2. The results of the study were 92.31% in sensitivity, 7.69% in false positive, 6.9% in false negative, and 10.26% in negative appendectomy. 3. None of case of leakage of barium by perforation of the inflamed appendix was noted, therefore, barium enema was thought to be safe as a diagnostic aid in acute appendicitis. 4. A simple partial or non filling of appendix without other associated positive finding could not exclude appendicitis, therefore, close clinical observation was necessary. 5. The positive findings of barium enema and their sensitivity were as followings: 1. Non filling of appendix: 90% 2. Partial filling of appendix: 91.7% 3. Displacement or a local impression on terminal ileum: 100%

  19. Enhanced sulfate reduction with acidogenic sulfate-reducing bacteria

    International Nuclear Information System (INIS)

    Sulfate reduction in a continuous flow, acidogenic reactor using molasses wastewater as the carbon source was studied at varying chemical oxygen demand/sulfate (COD/SO42-) ratios. At a critical COD/SO42- ratio of 2.7, neither COD nor sulfate were in excess for extra production of ethanol or acetate in the reactor. An acetic-type microbial metabolism was established with sulfate-reducing bacteria (SRB) significantly consuming hydrogen and volatile fatty acids produced by acidogenic bacteria and hydrogen producing acetogens in degrading COD, thereby yielding sulfate removal rate >94.6%. A low critical COD/SO42- ratio of 1.6 was also observed with the enriched ASRB population in reactor which overcomes the barrier to the treatment capability of sulfate-laden wastewater treatment with limited COD supply

  20. Influence of the preparation methods on the structure and magnetic properties of nanosized Al-substituted barium hexaferrite powders

    Science.gov (United States)

    Peneva, P.; Koutzarova, T.; Kolev, S.; Ghelev, Ch.; Vertruyen, B.; Henrist, C.; Closet, R.; Cloots, R.; Zaleski, A.

    2016-03-01

    We report studies on the correlation between the method of preparation, microstructure and magnetic properties of nanosized monodomain Al-substituted barium hexaferrite (BaAlFe11O19) powders. The powders were obtained by the co-precipitation and single microemulsion methods. The particles in the samples had a size between 80 nm and 135 nm depending on the synthesis conditions. The value of the saturation magnetization Ms measured was very high, namely, 66.12 emu/g. The hysteresis loop was very narrow, with the coercivity Hc being 163 Oe, which indicated that the particles were in a near-superparamagnetic state.

  1. Characterization of trace metals on soot aerosol particles with the SP-AMS: detection and quantification

    Science.gov (United States)

    Carbone, S.; Onasch, T.; Saarikoski, S.; Timonen, H.; Saarnio, K.; Sueper, D.; Rönkkö, T.; Pirjola, L.; Häyrinen, A.; Worsnop, D.; Hillamo, R.

    2015-11-01

    A method to detect and quantify mass concentrations of trace metals on soot particles by the Aerodyne soot-particle aerosol mass spectrometer (SP-AMS) was developed and evaluated in this study. The generation of monodisperse Regal black (RB) test particles with trace amounts of 13 different metals (Na, Al, Ca, V, Cr, Mn, Fe, Ni, Cu, Zn, Rb, Sr and Ba) allowed for the determination of the relative ionization efficiency of each metal relative to black carbon (RIEmeas). The observed RIEmeas / RIEtheory values were larger than unity for Na, Rb, Ca, Sr and Ba due to thermal surface ionization (TSI) on the surface of the laser-heated RB particles. Values closer to unity were obtained for the transition metals Zn, Cu, V and Cr. Mn, Fe, and Ni presented the lowest RIEmeas / RIEtheory ratios and highest deviation from unity. The latter discrepancy is unexplained; however it may be related to problems with our calibration method and/or the formation of metal complexes that were not successfully quantified. The response of the metals to the laser power was investigated and the results indicated that a minimum pump laser current of 0.6 A was needed in order to vaporize the metals and the refractory black carbon (rBC). Isotopic patterns of metals were resolved from high-resolution mass spectra, and the mass-weighted size distributions for each individual metal ion were obtained using the high-resolution particle time-of-flight (HR-PToF) method. The RIEmeas values obtained in this study were applied to the data of emission measurements in a heavy-fuel-oil-fired heating station. Emission measurements revealed a large number of trace metals, including evidence for metal oxides and metallic salts, such as vanadium sulfate, calcium sulfate, iron sulfate and barium sulfate, which were identified in the SP-AMS high-resolution mass spectra. SP-AMS measurements of Ba, Fe, and V agreed with ICP-MS analyzed filter samples within a factor of 2 when emitted rBC mass loadings were elevated.

  2. Crystal structure of tris­(piperidinium) hydrogen sulfate sulfate

    OpenAIRE

    Tamara J. Lukianova; Vasyl Kinzhybalo; Adam Pietraszko

    2015-01-01

    In the title molecular salt, 3C5H12N+·HSO4−·SO42−, each cation adopts a chair conformation. In the crystal, the hydrogen sulfate ion is connected to the sulfate ion by a strong O—H...O hydrogen bond. The packing also features a number of N—H...O hydrogen bonds, which lead to a three-dimensional network structure. The hydrogen sulfate anion accepts four hydrogen bonds from two cations, whereas the sulfate ion, as an acceptor, binds to five separate piperidinium cations, forming seven hydrogen ...

  3. Calibration and measurement uncertainties of a continuous-flow cloud condensation nuclei counter (DMT-CCNC: CCN activation of ammonium sulfate and sodium chloride aerosol particles in theory and experiment

    Directory of Open Access Journals (Sweden)

    D. Rose

    2007-06-01

    Full Text Available Experimental and theoretical uncertainties in the measurement of cloud condensation nuclei (CCN with a continuous-flow thermal-gradient CCN counter from Droplet Measurement Technologies (DMT-CCNC have been assessed by model calculations and calibration experiments with ammonium sulfate and sodium chloride aerosol particles in the diameter range of 20–220 nm. Experiments have been performed in the laboratory and during field measurement campaigns, extending over a period of more than one year and covering a wide range of operating conditions (650–1020 hPa ambient pressure, 0.5–1.0 L min−1 aerosol flow rate, 20–30°C inlet temperature, 4–34 K m−1 temperature gradient. For each set of conditions, the effective water vapor supersaturation (Seff in the CCNC was determined from the measured CCN activation spectra and Köhler model calculations.

    High measurement precision was achieved under stable laboratory conditions, where relative variations of Seff in the CCNC were generally less than ±2%. During field measurements, however, the relative variability increased up to ±5–7%, which can be mostly attributed to variations of the CCNC column top temperature with ambient temperature.

    To assess the accuracy of the Köhler models used to calculate Seff, we have performed a comprehensive comparison and uncertainty analysis of the various Köhler models and thermodynamic parameterizations commonly used in CCN studies. For the relevant supersaturation range (0.05–2%, the relative deviations between different modeling approaches were as high as 25% for (NH42SO4 and 16% for NaCl. The deviations were mostly caused by the different parameterizations for the activity of water in aqueous solutions of (NH42SO4 and NaCl (activity parameterization, osmotic coefficient, and van't Hoff

  4. Binding of heparan sulfate to Staphylococcus aureus.

    OpenAIRE

    Liang, O D; Ascencio, F; Fransson, L A; Wadström, T

    1992-01-01

    Heparan sulfate binds to proteins present on the surface of Staphylococcus aureus cells. Binding of 125I-heparan sulfate to S. aureus was time dependent, saturable, and influenced by pH and ionic strength, and cell-bound 125I-heparan sulfate was displaced by unlabelled heparan sulfate or heparin. Other glycosaminoglycans of comparable size (chondroitin sulfate and dermatan sulfate), highly glycosylated glycoprotein (hog gastric mucin), and some anionic polysaccharides (dextran sulfate and RNA...

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

    Science.gov (United States)

    Septiani, Ardita; Idayanti, Novrita; Kristiantoro, Tony

    2016-02-01

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

  6. Nanosized barium hexaferrite in novolac phenolic resin as microwave absorber for X-band application

    International Nuclear Information System (INIS)

    Nanosized barium ferrite (BaFe12O19) with Novolac phenolic resin (NPR) is developed as a magnetic absorber for application in the frequency range 8.2–12.4 GHz. The absorption is studied by modifying the microstructural properties of the ferrite inclusion with annealing temperature and its content in the composite. Transmission electron microscopy and X-ray diffraction pattern confirms the formation of hexagonal structure of barium ferrite. The crystallite size of the barium ferrite particles is in nano-range and increases with annealing temperature. The BaFe12O19/NPR composite is prepared with different weight percentage of ferrite inclusions. The complex permittivity and complex permeability is measured at X-band and found to increase with annealing temperature and contents of ferrite inclusion. Theoretical study of reflection loss gives that 2 mm absorber samples are showing the best results for X-band application. Reflection loss measurement of the samples shows absorption peak of −24.61 dB at 10.26 GHz for 30 wt%, −28.39 dB at 9.98 GHz for 40 wt% and −37.06 dB at 9.5 GHz for 50 wt% of BaFe12O19 in NPR matrix. - Highlights: • BaFe12O19/NPR composite is developed as microwave absorbing material. • The maximal absorption is optimized with thickness using TLM. • Calculated reflection loss of 50 wt% for 2 mm thickness is 41.05 dB at 9.95 GHz. • Measured reflection loss of 50 wt% for 2 mm thickness is 37.06 dB at 9.5 GHz

  7. Nanosized barium hexaferrite in novolac phenolic resin as microwave absorber for X-band application

    Energy Technology Data Exchange (ETDEWEB)

    Ozah, S.; Bhattacharyya, N.S., E-mail: nidhisbhatta@gmail.com

    2013-09-15

    Nanosized barium ferrite (BaFe{sub 12}O{sub 19}) with Novolac phenolic resin (NPR) is developed as a magnetic absorber for application in the frequency range 8.2–12.4 GHz. The absorption is studied by modifying the microstructural properties of the ferrite inclusion with annealing temperature and its content in the composite. Transmission electron microscopy and X-ray diffraction pattern confirms the formation of hexagonal structure of barium ferrite. The crystallite size of the barium ferrite particles is in nano-range and increases with annealing temperature. The BaFe{sub 12}O{sub 19}/NPR composite is prepared with different weight percentage of ferrite inclusions. The complex permittivity and complex permeability is measured at X-band and found to increase with annealing temperature and contents of ferrite inclusion. Theoretical study of reflection loss gives that 2 mm absorber samples are showing the best results for X-band application. Reflection loss measurement of the samples shows absorption peak of −24.61 dB at 10.26 GHz for 30 wt%, −28.39 dB at 9.98 GHz for 40 wt% and −37.06 dB at 9.5 GHz for 50 wt% of BaFe{sub 12}O{sub 19} in NPR matrix. - Highlights: • BaFe{sub 12}O{sub 19}/NPR composite is developed as microwave absorbing material. • The maximal absorption is optimized with thickness using TLM. • Calculated reflection loss of 50 wt% for 2 mm thickness is 41.05 dB at 9.95 GHz. • Measured reflection loss of 50 wt% for 2 mm thickness is 37.06 dB at 9.5 GHz.

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

    Science.gov (United States)

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

    2010-01-01

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

  9. Studies of hexacelsian and celsian barium aluminosilicates

    Science.gov (United States)

    Lee, Kuo-Tong

    1998-09-01

    The first part of this work (chapter 3) describes the reaction paths leading to the formation of BaAlsb2Sisb2Osb8 (BAS) from a mixture of gamma-BaCOsb3,\\ alpha-Alsb2Osb3, and amorphous SiOsb2 powders. Heat treatments conducted from 600 to 1200sp°C in air were used to transform the powder mixtures into hexacelsian BAS. The phase evolution to BAS was examined by x-ray diffraction. Several experiments were designed to microscopically reproduce the solid-solid interfaces expected during the synthesis of BAS and enabled the author to describe the different stages of the reaction. There exist two reaction paths in formation of BAS in this study: (1) formation of a series of barium silicates leading to BaO*2SiOsb2 (BSsb2) which then reacts with Alsb2Osb3 to form BAS and (2) formation of BaO*Alsb2Osb3 (BA) which then reacts with SiOsb2 to form BAS. The kinetics of the latter is slower than that of the former because the reaction between BaO*Alsb2Osb3 and SiOsb2 to form BAS includes a bond breaking process. The second part (chapter 4) of this research was undertaken to study the role of additives on the kinetics of the transformation of hexacelsian to celsian. Pre-synthesized hexacelsian powders doped with various additives were heated at temperatures ranging from 850 to 1400sp°C for 4 hrs. Semi-quantitative analysis of XRD was used to determine the extent of the hexacelsian-to-celsian transformation. This work was extended further to investigate the mechanisms involved in the transformation. Defect structures developed in the additive-containing celsian provide insights about the sites occupied by the cations added. Experimental results indicate that the doping of ˜0.99A cations in promoting the conversion of hexacelsian to celsian is by forming an interstitial solid solution in hexacelsian and ˜0.66A cations form a substitutional solid solution. In a kinetic study on the CaO- or MgO-enhanced transformation, values of rate constant, k, and Avlami constant, n, at

  10. Occupational doses in pediatric barium meal procedures

    International Nuclear Information System (INIS)

    Ionizing radiation has become an indispensable tool when it comes to diagnosis and therapy. However, its use should happen in a rational manner, taking into account the risks to which the staff is being exposed. Barium meal (BM), or upper gastrointestinal (GI) studies, using fluoroscopy, are widely used for gastroesophageal reflux disease diagnostic in children and professionals are required to stay inside the examination room to position and immobilize pediatric patients during the procedure. Therefore, it is very important that proffessionals strictly follow the technical standards of radiation protection. According to the ICRP and the NCRP recommendations, the annual limit equivalent doses for eyes, thyroid and hands are, espectively, 20 mSv, 150 mSv and 500 mSv. Based on those data, the aim of the current study is to estimate the annual equivalent dose for eyes, thyroid and hands of professionals who perform BM procedures in children. This was done using properly package LiF:Mg,Cu,P thermoluminescent dosimeters in 37 procedures; 2 pairs were positioned near each staff´s eye, 2 pairs on each professional´s neck (on and under the lead protector) and 2 pairs on both staff´s hands. The range of the estimative annual equivalent doses, for eyes, thyroid and hands, are, respectively: 14 – 36 mSv, 7 – 22 mSv and 14 – 58 mSv. Only the closest staff to the patient exceeded the annual equivalent doses in the eyes (around 80% higher than the limit set by ICRP). However, the results from this study, for hands and thyroid, compared to similar studies, show higher values. Therefore, the optimization implementation is necessary, so that the radiation levels can be reduced. (authors)

  11. Method for the extraction chromatographic separation of barium from other elements with dibenzo-18-crown-6

    International Nuclear Information System (INIS)

    A method has been developed for the extraction chromatographic separation of barium from 0.01 M picric acid solution with dibenzo-18-crown-6 coated on hydrophobic silica gel as the stationary phase. Various mineral acids can be used as stripping agents. Barium was separated from other elements by selective extraction and the separation of barium from alkali and alkaline earth metals, uranium, thorium and lead was achieved. The method was applied to the determination of barium in real samples. (author)

  12. Electron microscopy of barium bismuth titanate multilayer ceramics

    International Nuclear Information System (INIS)

    For a number of years bismuth containing compounds have been used with pre-calcined barium titanate to reduce the sintering temperature of the capacitor formulations. As reported earlier the backscattered electron (BSE) SEM micrographs of the bismuth containing barium titanate ceramic reveal that the grains having an average size of 1.2μm consist of a two phase structure consisting of relatively pure barium titanate grain cores surrounded by bismuth rich grain shells. The TEM and STEM studies along with the EDS analyses show that the bismuth concentration increases sharply as one steps towards the grain boundary with a maximum bismuth content at the grain boundary. It is the purpose of this work to investigate the distribution of bismuth in these formulations including the bismuth content, if any, at the ceramic metal interface as affected by the sintering temperature. The subsequent effect on the electrical resistivity of these ceramics in the multilayer configuration is reported

  13. Barium titanate thick films prepared by screen printing technique

    Directory of Open Access Journals (Sweden)

    Mirjana M. Vijatović

    2010-06-01

    Full Text Available The barium titanate (BaTiO3 thick films were prepared by screen printing technique using powders obtained by soft chemical route, modified Pechini process. Three different barium titanate powders were prepared: i pure, ii doped with lanthanum and iii doped with antimony. Pastes for screen printing were prepared using previously obtained powders. The thick films were deposited onto Al2O3 substrates and fired at 850°C together with electrode material (silver/palladium in the moving belt furnace in the air atmosphere. Measurements of thickness and roughness of barium titanate thick films were performed. The electrical properties of thick films such as dielectric constant, dielectric losses, Curie temperature, hysteresis loop were reported. The influence of different factors on electrical properties values was analyzed.

  14. Compact pulse forming line using barium titanate ceramic material

    Science.gov (United States)

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

    2011-11-01

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

  15. Compact pulse forming line using barium titanate ceramic material.

    Science.gov (United States)

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

    2011-11-01

    Ceramic material has very high relative permittivity, so compact pulse forming line can be made using these materials. Barium titanate (BaTiO(3)) has a relative permittivity of 1200 so it is used for making compact pulse forming line (PFL). Barium titanate also has piezoelectric effects so it cracks during high voltages discharges due to stresses developed in it. Barium titanate is mixed with rubber which absorbs the piezoelectric stresses when the PFL is charged and regain its original shape after the discharge. A composite mixture of barium titanate with the neoprene rubber is prepared. The relative permittivity of the composite mixture is measured to be 85. A coaxial pulse forming line of inner diameter 120 mm, outer diameter 240 mm, and length 350 mm is made and the composite mixture of barium titanate and neoprene rubber is filled between the inner and outer cylinders. The PFL is charged up to 120 kV and discharged into 5 Ω load. The voltage pulse of 70 kV, 21 ns is measured across the load. The conventional PFL is made up of oil or plastics dielectrics with the relative permittivity of 2-10 [D. R. Linde, CRC Handbook of Chemistry and Physics, 90th ed. (CRC, 2009); Xia et al., Rev. Sci. Instrum. 79, 086113 (2008); Yang et al., Rev. Sci. Instrum. 81, 43303 (2010)], which increases the length of PFL. We have reported the compactness in length achieved due to increase in relative permittivity of composite mixture by adding barium titanate in neoprene rubber. PMID:22129008

  16. 49 CFR 173.182 - Barium azide-50 percent or more water wet.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Barium azide-50 percent or more water wet. 173.182 Section 173.182 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS... Class 1 and Class 7 § 173.182 Barium azide—50 percent or more water wet. Barium azide—50 percent or...

  17. 21 CFR 201.304 - Tannic acid and barium enema preparations.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Tannic acid and barium enema preparations. 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 improve X-ray pictures. Tannic acid is capable of causing diminished...

  18. 40 CFR 721.10010 - Barium manganese oxide (BaMnO3).

    Science.gov (United States)

    2010-07-01

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

  19. Esophageal intramural pseudodiverticulosis characterized by barium esophagography: a case report

    LENUS (Irish Health Repository)

    O'Connor, Owen J

    2010-05-21

    Abstract Introduction Esophageal intramural pseudodiverticulosis is a rare condition characterized by the dilatation of the submucosal glands. Case presentation We present a case of esophageal intramural pseudodiverticulosis in a 72-year-old Caucasian man who presented with dysphagia and with a background history of alcohol abuse. An upper gastrointestinal endoscopy of our patient showed an esophageal stricture with abnormal mucosal appearances, but no malignant cells were seen at biopsy. Appearances on a barium esophagram were pathognomonic for esophageal intramural pseudodiverticulosis. Conclusion We demonstrate the enduring usefulness of barium esophagography in the characterization of abnormal mucosal appearances at endoscopy.

  20. Photoionization and Photoelectric Loading of Barium Ion Traps

    CERN Document Server

    Steele, A V; Churchill, L R; Griffin, P F

    2007-01-01

    Simple and effective techniques for loading barium ions into linear Paul traps are demonstrated. Two-step photoionization of neutral barium is achieved using a weak intercombination line (6s2 1S0 6s6p 3P1, 791 nm) followed by excitation above the ionization threshold using a nitrogen gas laser (337 nm). Isotopic selectivity is achieved by using a near Doppler-free geometry for excitation of the triplet 6s6p 3P1 state. Additionally, we report a particularly simple and efficient trap loading technique that employs an in-expensive UV epoxy curing lamp to generate photoelectrons.

  1. Photoionization and Photoelectric Loading of Barium Ion Traps

    OpenAIRE

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

    2007-01-01

    Simple and effective techniques for loading barium ions into linear Paul traps are demonstrated. Two-step photoionization of neutral barium is achieved using a weak intercombination line (6s2 1S0 6s6p 3P1, 791 nm) followed by excitation above the ionization threshold using a nitrogen gas laser (337 nm). Isotopic selectivity is achieved by using a near Doppler-free geometry for excitation of the triplet 6s6p 3P1 state. Additionally, we report a particularly simple and efficient trap loading t...

  2. Equations of state for barium in high-pressure phases

    International Nuclear Information System (INIS)

    The universal equation of state with an arbitrary reference point presented by the author (Fang Zheng-Hua 1998 Phys. Rev. B 50 16 238) is applied successfully to the analysis of the experimental compression data of barium in different structural phases (I, II, and V). The comparison given in this paper shows that this equation suits for the isothermal compression behaviour of barium in the high-pressure phases (II and V) better than the Birch-Murnaghan equation. The applicability of equations of state for solids in high-pressure phases is also discussed. (author)

  3. Synthesis of nanosized barium titanate/epoxy resin composites and measurement of microwave absorption

    Indian Academy of Sciences (India)

    M Murugan; V K Kokate; M S Bapat; A M Sapkal

    2010-12-01

    Barium titanate/epoxy resin composites have been synthesized and tested for microwave absorption/transmission. Nanocrystalline barium titanate (BaTiO3 or BT) was synthesized by the hydrothermal method and the composites of BT/epoxy resin were fabricated as thin solid slabs of four different weight ratios. BT was obtained in the cubic phase with an average particle size of 21 nm, deduced from the X-ray diffraction data. The reflection loss (RL) and transmission loss (TL) of the composite materials were measured by the reflection/transmission method using a vector network analyser R&S: ZVA40, in the frequency range 8.0–18.5 GHz (X and Ku-bands). The RL was found to be better than −10 dB over wide frequency bands. The higher RL for lower concentration of BT could be due to increase in impedance matching effects. Low TL values indicate that the absorption by BT is quite low. This could be due to formation of BT in the cubic paraelectric phase.

  4. Influence of Nanocrystalline Ferrite Particles on Properties of Magnetic Systems

    Science.gov (United States)

    Mueller, Robert; Habisreuther, Tobias; Hiergeist, Robert; Steinmetz, Hanna; Zeisberger, Matthias; Gawalek, Wolfgang

    Nanocrystalline mainly superparamagnetic ferrite particles ≈ 10 nm are used for the preparation of magnetic fluids. Barium hexaferrite BaFe12-2xTixCoxO19 powders with mean particle sizes Isopar M or dodecane as carrier liquid. Small Angle Neutron Scattering curves lead to a bimodal size distribution consisting of single magnetic particles and aggregated magnetic particles. Particle size investigations were done by TEM.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

  6. Chemical abundance analysis of 19 barium stars

    Science.gov (United States)

    Yang, Guo-Chao; Liang, Yan-Chun; Spite, Monique; Chen, Yu-Qin; Zhao, Gang; Zhang, Bo; Liu, Guo-Qing; Liu, Yu-Juan; Liu, Nian; Deng, Li-Cai; Spite, Francois; Hill, Vanessa; Zhang, Cai-Xia

    2016-01-01

    We aim at deriving accurate atmospheric parameters and chemical abundances of 19 barium (Ba) stars, including both strong and mild Ba stars, based on the high signal-to-noise ratio and high resolution Echelle spectra obtained from the 2.16 m telescope at Xinglong station of National Astronomical Observatories, Chinese Academy of Sciences. The chemical abundances of the sample stars were obtained from an LTE, plane-parallel and line-blanketed atmospheric model by inputting the atmospheric parameters (effective temperatures Teff, surface gravities log g, metallicity [Fe/H] and microturbulence velocity ξt) and equivalent widths of stellar absorption lines. These samples of Ba stars are giants as indicated by atmospheric parameters, metallicities and kinematic analysis about UVW velocity. Chemical abundances of 17 elements were obtained for these Ba stars. Their Na, Al, α- and iron-peak elements (O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Ni) are similar to the solar abundances. Our samples of Ba stars show obvious overabundances of neutron-capture (n-capture) process elements relative to the Sun. Their median abundances of [Ba/Fe], [La/Fe] and [Eu/Fe] are 0.54, 0.65 and 0.40, respectively. The Y I and Zr I abundances are lower than Ba, La and Eu, but higher than the α- and iron-peak elements for the strong Ba stars and similar to the iron-peak elements for the mild stars. There exists a positive correlation between Ba intensity and [Ba/Fe]. For the n-capture elements (Y, Zr, Ba, La), there is an anti-correlation between their [X/Fe] and [Fe/H]. We identify nine of our sample stars as strong Ba stars with [Ba/Fe] >0.6 where seven of them have Ba intensity Ba=2-5, one has Ba=1.5 and another one has Ba=1.0. The remaining ten stars are classified as mild Ba stars with 0.17<[Ba/Fe] <0.54.

  7. Preparation of meta-stable phases of barium titanate by Sol-hydrothermal method

    International Nuclear Information System (INIS)

    Two low-cost chemical methods of sol–gel and the hydrothermal process have been strategically combined to fabricate barium titanate (BaTiO3) nanopowders. This method was tested for various synthesis temperatures (100 °C to 250 °C) employing barium dichloride (BaCl2) and titanium tetrachloride (TiCl4) as precursors and sodium hydroxide (NaOH) as mineralizer for synthesis of BaTiO3 nanopowders. The as-prepared BaTiO3 powders were investigated for structural characteristics using x-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The overall analysis indicates that the hydrothermal conditions create a gentle environment to promote the formation of crystalline phase directly from amorphous phase at the very low processing temperatures investigated. XRD analysis showed phase transitions from cubic - tetragonal - orthorhombic - rhombohedral with increasing synthesis temperature and calculated grain sizes were 34 – 38 nm (using the Scherrer formula). SEM and TEM analysis verified that the BaTiO3 nanopowders synthesized by this method were spherical in shape and about 114 - 170 nm in size. The particle distribution in both SEM and TEM shows that as the reaction temperature increases from 100 °C to 250 °C, the particles agglomerate. Selective area electron diffraction (SAED) shows that the particles are crystalline in nature. The study shows that choosing suitable precursor and optimizing pressure and temperature; different meta-stable (ferroelectric) phases of undoped BaTiO3 nanopowders can be stabilized by the sol-hydrothermal method

  8. Preparation of meta-stable phases of barium titanate by Sol-hydrothermal method

    Directory of Open Access Journals (Sweden)

    Mahalakshmi Selvaraj

    2015-11-01

    Full Text Available Two low-cost chemical methods of sol–gel and the hydrothermal process have been strategically combined to fabricate barium titanate (BaTiO3 nanopowders. This method was tested for various synthesis temperatures (100 °C to 250 °C employing barium dichloride (BaCl2 and titanium tetrachloride (TiCl4 as precursors and sodium hydroxide (NaOH as mineralizer for synthesis of BaTiO3 nanopowders. The as-prepared BaTiO3 powders were investigated for structural characteristics using x-ray diffraction (XRD, scanning electron microscopy (SEM and transmission electron microscopy (TEM. The overall analysis indicates that the hydrothermal conditions create a gentle environment to promote the formation of crystalline phase directly from amorphous phase at the very low processing temperatures investigated. XRD analysis showed phase transitions from cubic - tetragonal - orthorhombic - rhombohedral with increasing synthesis temperature and calculated grain sizes were 34 – 38 nm (using the Scherrer formula. SEM and TEM analysis verified that the BaTiO3 nanopowders synthesized by this method were spherical in shape and about 114 - 170 nm in size. The particle distribution in both SEM and TEM shows that as the reaction temperature increases from 100 °C to 250 °C, the particles agglomerate. Selective area electron diffraction (SAED shows that the particles are crystalline in nature. The study shows that choosing suitable precursor and optimizing pressure and temperature; different meta-stable (ferroelectric phases of undoped BaTiO3 nanopowders can be stabilized by the sol-hydrothermal method.

  9. Preparation of meta-stable phases of barium titanate by Sol-hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Selvaraj, Mahalakshmi [Department of Physics, R.D. Govt. Arts College, Tamilnadu, Sivaganga - 630561 (India); Department of Material Science, School of Chemistry, Madurai Kamaraj University, Tamilnadu Madurai-625 021 (India); Venkatachalapathy, V. [Department of Physics/Centre for Materials Science and Nanotechnology, University of Oslo, P.O Box 1048 Blindern, NO-0316 Oslo (Norway); Mayandi, J., E-mail: pearce@mtu.edu, E-mail: jeyanthinath@yahoo.co.in [Department of Material Science, School of Chemistry, Madurai Kamaraj University, Tamilnadu Madurai-625 021 (India); Department of Materials Science & Engineering, Michigan Technological University (United States); Karazhanov, S. [Department of Solar Energy, Institute for Energy Technology, P.O. Box 40, NO-2027 Kjeller (Norway); Pearce, J. M., E-mail: pearce@mtu.edu, E-mail: jeyanthinath@yahoo.co.in [Department of Materials Science & Engineering, Michigan Technological University (United States); Department of Electrical & Computer Engineering, Michigan Technological University (United States)

    2015-11-15

    Two low-cost chemical methods of sol–gel and the hydrothermal process have been strategically combined to fabricate barium titanate (BaTiO{sub 3}) nanopowders. This method was tested for various synthesis temperatures (100 °C to 250 °C) employing barium dichloride (BaCl{sub 2}) and titanium tetrachloride (TiCl{sub 4}) as precursors and sodium hydroxide (NaOH) as mineralizer for synthesis of BaTiO{sub 3} nanopowders. The as-prepared BaTiO{sub 3} powders were investigated for structural characteristics using x-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The overall analysis indicates that the hydrothermal conditions create a gentle environment to promote the formation of crystalline phase directly from amorphous phase at the very low processing temperatures investigated. XRD analysis showed phase transitions from cubic - tetragonal - orthorhombic - rhombohedral with increasing synthesis temperature and calculated grain sizes were 34 – 38 nm (using the Scherrer formula). SEM and TEM analysis verified that the BaTiO{sub 3} nanopowders synthesized by this method were spherical in shape and about 114 - 170 nm in size. The particle distribution in both SEM and TEM shows that as the reaction temperature increases from 100 °C to 250 °C, the particles agglomerate. Selective area electron diffraction (SAED) shows that the particles are crystalline in nature. The study shows that choosing suitable precursor and optimizing pressure and temperature; different meta-stable (ferroelectric) phases of undoped BaTiO{sub 3} nanopowders can be stabilized by the sol-hydrothermal method.

  10. Acid Sulfate Alteration in Gusev Crater, Mars

    Science.gov (United States)

    Morris, R. V.; Ming, D. W.; Catalano, J. G.

    2016-01-01

    The Mars Exploration Rover (MER) Spirit landed on the Gusev Crater plains west of the Columbia Hills in January, 2004, during the Martian summer (sol 0; sol = 1 Martian day = 24 hr 40 min). Spirit explored the Columbia Hills of Gusev Crater in the vicinity of Home Plate at the onset on its second winter (sol approximately 900) until the onset of its fourth winter (sol approximately 2170). At that time, Spirit became mired in a deposit of fined-grained and sulfate-rich soil with dust-covered solar panels and unfavorable pointing of the solar arrays toward the sun. Spirit has not communicated with the Earth since sol 2210 (January, 2011). Like its twin rover Opportunity, which landed on the opposite side of Mars at Meridiani Planum, Spirit has an Alpha Particle X-Ray Spectrometer (APXS) instrument for chemical analyses and a Moessbauer spectrometer (MB) for measurement of iron redox state, mineralogical speciation, and quantitative distribution among oxidation (Fe(3+)/sigma Fe) and coordination (octahedral versus tetrahedral) states and mineralogical speciation (e.g., olivine, pyroxene, ilmenite, carbonate, and sulfate). The concentration of SO3 in Gusev rocks and soils varies from approximately 1 to approximately 34 wt%. Because the APXS instrument does not detect low atomic number elements (e.g., H and C), major-element oxide concentrations are normalized to sum to 100 wt%, i.e., contributions of H2O, CO2, NO2, etc. to the bulk composition care not considered. The majority of Gusev samples have approximately 6 plus or minus 5 wt% SO3, but there is a group of samples with high SO3 concentrations (approximately 30 wt%) and high total iron concentrations (approximately 20 wt%). There is also a group with low total Fe and SO3 concentrations that is also characterized by high SiO2 concentrations (greater than 70 wt%). The trend labeled "Basaltic Soil" is interpreted as mixtures in variable proportions between unaltered igneous material and oxidized and SO3-rich basaltic

  11. Enhanced transdermal delivery of salbutamol sulfate via ethosomes

    OpenAIRE

    Bendas, Ehab R.; Tadros, Mina I.

    2007-01-01

    The main objective of the present work was to compare the transdermal delivery of salbutamol sulfate (SS), a hydrophilic drug used as a bronchodilator, from ethosomes and classic liposomes containing different cholesterol and dicetylphosphate concentrations. All the systems were characterized for shape, particle size, and entrapment efficiency percentage, by image analysis optical microscopy or transmission electron microscopy, laser diffraction, and ultracentrifugation, respectively. In vitr...

  12. Zirconia doped barium titanate induced electroactive β polymorph in PVDF-HFP: high energy density and dielectric properties

    International Nuclear Information System (INIS)

    Zirconium-doped barium titanate (BZT-08, Ba(Ti0.92 Zr0.08)O3) particles were synthesized and PVDF-HFP-based composites were prepared by melt mixing to design materials with tunable dielectric and ferroelectric properties. Composites of PVDF-HFP and barium titanate (BT) particles were also prepared to realize the exceptional properties associated with the BZT-08-like stabilization of two ferroelectric phases, i.e. tetragonal and orthorhombic at room temperature. To facilitate the uniform dispersion and interfacial adhesion with the matrix, the particles were modified with (3-aminopropyl) triethoxysilane. The dependence of the dielectric and ferroelectric properties of the as-prepared composites were systematically investigated in this study with respect to a wide range of frequencies. The composites with BZT-08 exhibited the significantly high dielectric permittivity of ca. 26 (at 100 Hz) and a high energy density (2.7 J cm−3 measured on 100 μm thick film) at room temperature with respect to the control PVDF-HFP and PVDF-HFP/BT composites. Interestingly, the BZT-08 particles facilitated the electroactive β polymorph in the PVDF-HFP and enhanced polarization in the composites, leading to improved ferroelectric properties in the composites. (paper)

  13. BARIUM AND RADIUM REMOVAL FROM GROUNDWATER BY ION EXCHANGE

    Science.gov (United States)

    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

    Science.gov (United States)

    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. Barium titanate inverted opals-synthesis, characterization, and optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Soten, I.; Miguez, H.; Yang, S.M.; Petrov, S.; Coombs, N.; Tetreault, N.; Ozin, G.A. [Toronto Univ., ON (Canada). Dept. of Chemistry; Matsuura, N.; Ruda, H.E. [Toronto Univ., ON (Canada). Dept. of Metallurgy and Materials Science

    2002-01-01

    The engineering of cubic or tetragonal polymorphs of nanocrystalline barium titanate inverted opals has been achieved by thermally induced transformations. Optical characterization demonstrated photonic crystal behavior of the opals. The tuning of the ferroelectric-paraelectric transition around the Curie temperature is shown in this paper. (orig.)

  16. Nanocrystals formation on Ho3+ doped strontium barium niobate glass

    International Nuclear Information System (INIS)

    The study of two different methods to obtain strontium barium niobate nanocrystals immersed in a glass matrix has been carried out. Ho2O3-doped SrO-BaO-Nb2O5-B2O3 glasses were fabricated using the melt quenching method. Glass ceramic samples were obtained from the precursor glass by thermal treatment in a furnace and by laser irradiation. These glass ceramic samples are formed by a glassy phase and a crystalline phase of strontium barium niobate nanocrystals. This structure was confirmed by X-ray diffraction and Atomic Force Microscope images. The incorporation of Ho3+ ions in the strontium barium niobate nanocrystals were corroborated by optical measurements, which produced an increment in the luminescence intensity compared to the precursor glass. - Research Highlights: →Ho doped strontium barium niobate nanocrystals have been obtained. →XRD, AFM and optical measurements corroborate the formation of SBN. →A laser irradiation technique has been carried out successfully.

  17. Removal of barium and radium from groundwater. Environmental research brief

    International Nuclear Information System (INIS)

    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 removal processes were also characterized, and processes suitable for treatment of ion-exchange brines were evaluated. The report discusses two ion-exchange processes that can be used for barium and radium removal accompanied by either partial or no hardness removal. The calcium-form, strong-acid ion-exchange resin can be used for barium and radium removal without significant change in hardness or the concentration of other salts. This resin can be regenerated with CaC12 brine. The radium-selective complexer (RSC) will remove radium without altering hardness or other salt concentration. The capacity of this resin for waters with low total dissolved solids (TDS) (<1000 to 2000 mg/L TDS) is in excess of 30,000 pCi/dry g; however, if the TDS is increased to about 40,000 mg/L, the capacity drops to 200 to 300 pCi/dry g. Thus using this resin to remove radium from spent brine does not appear feasible

  18. CNO and F abundances in the barium star HD 123396

    CERN Document Server

    Alves-Brito, Alan; Yong, David; Meléndez, Jorge; Vásquez, Sergio

    2011-01-01

    [Abridged] Barium stars are moderately rare chemically peculiar objects which are believed to be the result of the pollution of an otherwise normal star by material from an evolved companion on the asymptotic giant branch (AGB). We aim to derive carbon, nitrogen, oxygen, and fluorine abundances for the first time from infrared spectra of the barium red giant star HD 123396 to quantitatively test AGB nucleosynthesis models for producing barium stars via mass accretion. High-resolution and high S/N infrared spectra were obtained using the Phoenix spectrograph mounted at the Gemini South telescope. The abundances were obtained through spectrum synthesis of individual atomic and molecular lines, using the MOOG stellar line analysis program together with Kurucz's stellar atmosphere models. The analysis was classical, using 1D stellar models and spectral synthesis under the assumption of local thermodynamic equilibrium. We confirm that HD 123396 is a metal-deficient barium star ([Fe/H] = -1.05), with A(C) = 7.88, A...

  19. Ultra-low temperature processing of barium tellurate dielectrics

    Science.gov (United States)

    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

  20. Biogenic, anthropogenic and sea salt sulfate size-segregated aerosols in the Arctic summer

    Science.gov (United States)

    Ghahremaninezhad, Roghayeh; Norman, Ann-Lise; Abbatt, Jonathan P. D.; Levasseur, Maurice; Thomas, Jennie L.

    2016-04-01

    Size-segregated aerosol sulfate concentrations were measured on board the Canadian Coast Guard Ship (CCGS) Amundsen in the Arctic during July 2014. The objective of this study was to utilize the isotopic composition of sulfate to address the contribution of anthropogenic and biogenic sources of aerosols to the growth of the different aerosol size fractions in the Arctic atmosphere. Non-sea-salt sulfate is divided into biogenic and anthropogenic sulfate using stable isotope apportionment techniques. A considerable amount of the average sulfate concentration in the fine aerosols with a diameter 63 %), which is higher than in previous Arctic studies measuring above the ocean during fall ( 30 %) (Norman et al., 1999). The anthropogenic sulfate concentration was less than that of biogenic sulfate, with potential sources being long-range transport and, more locally, the Amundsen's emissions. Despite attempts to minimize the influence of ship stack emissions, evidence from larger-sized particles demonstrates a contribution from local pollution. A comparison of δ34S values for SO2 and fine aerosols was used to show that gas-to-particle conversion likely occurred during most sampling periods. δ34S values for SO2 and fine aerosols were similar, suggesting the same source for SO2 and aerosol sulfate, except for two samples with a relatively high anthropogenic fraction in particles Ocean during the productive summer months.

  1. Multistage Tandem Mass Spectrometry of Chondroitin Sulfate and Dermatan Sulfate

    OpenAIRE

    Bielik, Alicia M.; Zaia, Joseph

    2011-01-01

    Chondroitin/dermatan sulfate (CS/DS) is a glycosaminoglycan (GAG) found in abundance in extracellular matrices. In connective tissue, CS/DS proteoglycans play structural roles in maintaining viscoelasticity through the large number of immobilized sulfate groups on CS/DS chains. CS/DS chains also bind protein families including growth factors and growth factor receptors. Through such interactions, CS/DS chains play important roles in neurobiochemical processes, connective tissue homeostasis, c...

  2. The impact of dust on sulfate aerosol, CN and CCN during an East Asian dust storm

    Directory of Open Access Journals (Sweden)

    P. T. Manktelow

    2010-01-01

    Full Text Available A global model of aerosol microphysics is used to simulate a large East Asian dust storm during the ACE-Asia experiment. We use the model together with size resolved measurements of aerosol number concentration and composition to examine how dust modified the production of sulfate aerosol and the particle size distribution in East Asian outflow. Simulated size distributions and mass concentrations of dust, sub- and super-micron sulfate agree well with observations from the C-130 aircraft. Modeled mass concentrations of fine sulfate (Dp<1.3 μm decrease by ~10% due to uptake of sulfur species onto super-micron dust. We estimate that dust enhanced the mass concentration of coarse sulfate (Dp>1.0 μm by more than an order of magnitude, but total sulfate concentrations increase by less than 2% because decreases in fine sulfate have a compensating effect. Our analysis shows that the sulfate associated with dust can be explained largely by the uptake of H2SO4 rather than reaction of SO2 on the dust surface, which we assume is suppressed once the particles are coated in sulfate. We suggest that many previous model investigations significantly overestimated SO2 oxidation on East Asian dust, possibly due to the neglect of surface saturation effects. We extend previous model experiments by examining how dust modified existing particle concentrations in Asian outflow. Total particle concentrations (condensation nuclei, CN modeled in the dust-pollution plume are reduced by up to 20%, but we predict that dust led to less than 10% depletion in particles large enough to act as cloud condensation nuclei (CCN. Our analysis suggests that E. Asian dust storms have only a minor impact on sulfate particles present at climate-relevant sizes.

  3. The impact of dust on sulfate aerosol, CN and CCN during an East Asian dust storm

    Directory of Open Access Journals (Sweden)

    P. T. Manktelow

    2009-07-01

    Full Text Available A global model of aerosol microphysics is used to simulate a large East Asian dust storm during the ACE-Asia experiment. We use the model together with size resolved measurements of aerosol number concentration and composition to examine how dust modified the production of sulfate aerosol and the particle size distribution in East Asian outflow. Simulated size distributions and mass concentrations of dust, sub- and super-micron sulfate agree well with observations from the C-130 aircraft. Modelled mass concentrations of fine sulfate (Dp<1.3 μm decrease by ~10% due to uptake of sulfur species onto super-micron dust. We estimate that dust enhanced the mass concentration of coarse sulfate (Dp<1.0 μm by more than an order of magnitude, but total sulfate concentrations increase by less than 2% because decreases in fine sulfate have a compensating effect. Our analysis shows that the sulfate associated with dust can be explained largely by the uptake of H2SO4 rather than reaction of SO2 on the dust surface, which we assume is suppressed once the particles are coated in sulfate. We suggest that many previous model investigations significantly overestimated SO2 oxidation on East Asian dust, possibly due to the neglect of surface saturation effects. We extend previous model experiments by examining how dust modified existing particle concentrations in Asian outflow. Total particle concentrations modelled in the dust-pollution plume are reduced by up to 20%, but we predict that dust led to less than 10% depletion in particles large enough to act as cloud condensation nuclei. Our analysis suggests that E. Asian dust storms have only a minor impact on sulfate particles present at climate-relevant sizes.

  4. Biological sulfate removal from acrylic fiber manufacturing wastewater using a two-stage UASB reactor

    Institute of Scientific and Technical Information of China (English)

    Jin Li; Jun Wang; Zhaokun Luan; Zhongguang Ji; Lian Yu

    2012-01-01

    A two-stage UASB reactor was employed to remove sulfate from acrylic fiber manufacturing wastewater.Mesophilic operation (35±0.5℃) was performed with hydraulic retention time (HRT) varied between 28 and 40 hr.Mixed liquor suspended solids (MLSS)in the reactor was maintained about 8000 mg/L.The results indicated that sulfate removal was enhanced with increasing the ratio of COD/SO42-.At low COD/SO42-,the growth of the sulfate-reducing bacteria (SRB) was carbon-limited.The optimal sulfate removal efficiencies were 75% when the HRT was no less than 38 hr.Sulfidogenesis mainly happened in the sulfate-reducing stage,while methanogenesis in the methane-producing stage.Microbes in sulfate-reducing stage performed granulation better than that in methaneproducing stage.Higher extracellular polymeric substances (EPS) content in sulfate-reducing stage helped to adhere and connect the flocculent sludge particles together.SRB accounted for about 31% both in sulfate-reducing stage and methane-producing stage at COD/SO42- ratio of 0.5,while it dropped dramatically from 34% in sulfate-reducing stage to 10% in methane-producing stage corresponding to the COD/SO42- ratio of 4.7.SRB and MPA were predominant in sulfate-reducing stage and methane-producing stage respectively.

  5. Preparation, characterization, and manipulation of iron platinum, barium titanate, and vanadium oxide nanoparticles

    Science.gov (United States)

    Morris, William Homer, III

    2008-12-01

    New synthesis strategies for preparation of FePt, BaTiO 3, VO2, V2O3, V2O5 , and V6O13 nanoparticles are presented in this thesis. Electron microscopy, diffraction, elemental analysis, and physical property measurement studies confirm the composition and structure of the synthesized material. Also reported is size-selection of ferromagnetic nanoparticles by binding PEG (2000 MW) ligand to particle surfaces and fractionally precipitating more narrowed size cuts. Large (30--100 nm) ferromagnetic nanoparticles are prepared by employing vesicle templates. Barium titanate nanoparticles with an average diameter of 3.8 nm have been synthesized within inverse micelles. A variety of vanadium oxide compositions within the nanometer size regime have been prepared using sol-gel chemistry.

  6. Synthesis and Characterization of Barium Titanate Powders by Sol-Gel Method

    International Nuclear Information System (INIS)

    BaTiO3 powders were prepared by the sol gel method starting from soluble precursors of barium and titanium. The synthesized powders were calcined for 2 h at different temperatures ranges from 800 to 1000 degree Celsius. Phase formation, crystal structure and crystallite size of the calcined powders were investigated using the x-ray diffraction (XRD). A scanning electron microscope (SEM) equipped with energy-dispersive x-ray spectroscopy (EDX) was used for determination of morphology and elemental composition. The XRD results showed that BaTiO3 transformed from the (pseudo)cubic to the ferroelectric tetragonal phase with increasing calcination temperature. The purity and crystallite size of BaTiO3 powders were found to increase with increasing calcination temperature in the range of 32 nm to 140 nm. Higher temperatures led to the particle growth and agglomeration. (author)

  7. Nonaqueous cold extrusion as a route for yttrium barium copper oxide wires

    International Nuclear Information System (INIS)

    Yttrium barium copper oxide (YBCO) superconducting wires of diameter 0.2 to 1 mm in the form of spirals up to 50 cm long were made by a novel nonaqueous cold extrusion technique. Finely ground YBCO powder having a set particle size distribution was intimately mixed with a polypropylene compound and extruded manually into wires which were heat-treated at controlled rates followed by oxygen annealing at 940 C for 10 h. These wires are superconducting with a Tc of 89.5 K, the XRD pattern exhibiting an orthorhombic single phase. Current density at zero field was measured to be 223 A/cm2. The surface morphology of the extruded wires and microstructure of the polished cross section of the sintered wires are also presented

  8. Poly (vinylidene fluoride-trifluoroethylene/barium titanate nanocomposite for ferroelectric nonvolatile memory devices

    Directory of Open Access Journals (Sweden)

    Uvais Valiyaneerilakkal

    2013-04-01

    Full Text Available The effect of barium titanate (BaTiO3 nanoparticles (particle size <100nm on the ferroelectric properties of poly (vinylidenefluoride-trifluoroethylene P(VDF-TrFE copolymer has been studied. Different concentrations of nanoparticles were added to P(VDF-TrFE using probe sonication, and uniform thin films were made. Polarisation - Electric field (P-E hysteresis analysis shows an increase in remnant polarization (Pr and decrease in coercive voltage (Vc. Piezo-response force microscopy analysis shows the switching capability of the polymer composite. The topography and surface roughness was studied using atomic force microscopy. It has been observed that this nanocomposite can be used for the fabrication of non-volatile ferroelectric memory devices.

  9. Properties of composition sinter prepared from fibrous barium titanate and nanometer zirconia

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Fibrous Batium Titanate particles,30-50 μm long,prepared by a hydrothermal reaction,and the monoclinic phase and nanometer Zirconia,11.6 nm long were prepared by citric acid reaction respectively.Then,the two were composite sintered to produce a new functional material by making full use of crystal-axis orientation of fibers and the activity of nanometer powder.The analydid of composition and microstructure of the new material in terms of XRD and SEM.shows that the solid solution was formed between fibers and nanometer powder,and the distance between lattice(d value)of Barium Titanate changed.But the crystal-axis orientations of fibers remain unchanged.

  10. Barium fluoride whispering-gallery-mode disk-resonator with one billion quality-factor

    CERN Document Server

    Lin, Guoping; Henriet, Rémi; Jacquot, Maxime; Chembo, Yanne K

    2015-01-01

    We demonstrate a monolithic optical whispering gallery mode resonator fabricated with barium fluoride (BaF$_2$) with an ultra-high quality ($Q$) factor above $10^9$ at $1550$ nm, and measured with both the linewidth and cavity-ring-down methods. Vertical scanning optical profilometry shows that the root mean square surface roughness of $2$ nm is achieved for our mm-size disk. To the best of our knowledge, we show for the first time that one billion $Q$-factor is achievable by precision polishing in relatively soft crystals with mohs hardness of ~$3$. We show that complex thermo-optical dynamics can take place in these resonators. Beside usual applications in nonlinear optics and microwave photonics, high energy particle scintillation detection utilizing monolithic BaF$_2$ resonators potentially becomes feasible.

  11. Barium fluoride whispering-gallery-mode disk-resonator with one billion quality-factor.

    Science.gov (United States)

    Lin, Guoping; Diallo, Souleymane; Henriet, Rémi; Jacquot, Maxime; Chembo, Yanne K

    2014-10-15

    We demonstrate a monolithic optical whispering-gallery-mode resonator fabricated with barium fluoride (BaF₂) with an ultra-high quality (Q) factor above 10⁹ at 1550 nm, and measured with both the linewidth and cavity-ring-down methods. Vertical scanning optical profilometry shows that the root mean square surface roughness of 2 nm is achieved for our mm-size disk. To the best of our knowledge, we show for the first time that one billion Q-factor is achievable by precision polishing in relatively soft crystals with mohs hardness of 3. We show that complex thermo-optical dynamics can take place in these resonators. Beside usual applications in nonlinear optics and microwave photonics, high-energy particle scintillation detection utilizing monolithic BaF₂ resonators potentially becomes feasible. PMID:25361142

  12. Radiation damage in barium fluoride detector materials

    Energy Technology Data Exchange (ETDEWEB)

    Levey, P.W.; Kierstead, J.A.; Woody, C.L.

    1988-01-01

    To develop radiation hard detectors, particularly for high energy physics studies, radiation damage is being studied in BaF/sub 2/, both undoped and doped with La, Ce, Nd, Eu, Gd and Tm. Some dopants reduce radiation damage. In La doped BaF/sub 2/ they reduce the unwanted long lifetime luminescence which interferes with the short-lived fluorescence used to detect particles. Radiation induced coloring is being studied with facilities for making optical measurements before, during and after irradiation with /sup 60/C0 gamma rays. Doses of 10/sup 6/ rad, or less, create only ionization induced charge transfer effects since lattice atom displacement damage is negligible at these doses. All crystals studied exhibit color center formation, between approximately 200 and 800 nm, during irradiation and color center decay after irradiation. Thus only measurements made during irradiation show the total absorption present in a radiation field. Both undoped and La doped BaF/sub 2/ develop damage at minimum detectable levels in the UV---which is important for particle detectors. For particle detector applications these studies must be extended to high dose irradiations with particles energetic enough to cause lattice atom displacement damage. In principle, the reduction in damage provided by dopants could apply to other applications requiring radiation damage resistant materials.

  13. Barium Doped Li2FeSiO4 Cathode Material for Li-Ion Secondary Batteries.

    Science.gov (United States)

    Kim, Cheong; Yoo, Gi Won; Son, Jong Tae

    2015-11-01

    Barium-doped Li2Fe(1-x)Ba(x)SiO4 (x = 0, 0.01) cathode materials were synthesized by the sol-gel and electrospinning processes. The structures of the samples were confirmed by X-ray diffraction and Fourier transform infrared spectroscopy. The sizes and the morphologies of the particles and nanofibers were observed by field emission scanning electron microscopy and atomic force microscopy. The initial discharge capacity of Li2FeSiO4 particles was 28 mAh/g, Li2FeSiO4 nanofibers and barium (Ba)-doped Li2FeSiO4 nanofibers showed the discharge capacities of 78 and 85 mAh/g, respectively. The lithium-ion diffusion coefficients of Li2FeSiO4 particles, Li2FeSiO4 nanofibers and Ba-doped Li2FeSiO4 nanofibers were calculated 5.15 x 10-(16), 3.52 x 10(-16), and 2.27 x 10(-15) cm2/s, respectively. The Ba-doped Li2FeSiO4 cathode material showed the highest lithium-ion diffusion coefficient, and its electrochemical properties were better than that of the pristine material. PMID:26726598

  14. Study of the Influence Between Barium Ions and Calcium Ions on Morphology and Size of Coprecipitation in Microemulsion

    Science.gov (United States)

    Wang, Nong; Meng, Qing Luo

    2015-03-01

    In this paper, we systematically drew a series of inverse-microemulsion quasi-ternary system phase diagrams of OP-10+C8H17OH+C6H12+brine (CaCl2/BaCl2) by adjusting the ratio of CaCl2 and BaCl2. On this basis, microemulsions have been prepared with seven different molar ratios of Ca2+/Ba2+, and calcium carbonate and barium carbonate coprecipitation products were obtained by reaction with an equimolar amount of sodium carbonate. The influence of barium ion to morphology and composition of nanometer calcium carbonate were studied. These samples were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The SEM photographs indicated that when the content of Ca2+ was higher, some incomplete large cube of coprecipitation particles were formed in solution, but with the content of Ba2+ increased gradually, they formed a large number of small spherical particles, with the further increase of Ba2+ concentration, the particles mainly had structures of irregular polyhedron eventually. The measurement results of FTIR and XRD indicated that CaCO3 coprecipitation products gradually changed from calcite to the vaterite, eventually turned into being aragonite with the further increase of Ba2+ concentration.

  15. Dielectric properties of lead zirconate titanate thin films seeded with barium strontium titanate nanoparticles

    International Nuclear Information System (INIS)

    A low temperature synthetic method recently proposed by the authors was applied to the fabrication of lead zirconate titanate (PZT) thin films containing crystalline seeds of barium strontium titanate (BST) nanoparticles. PZT precursor and the BST particles were prepared with complex alkoxide methods. Precursor solution suspending the BST particles was spin-coated on Pt/Ti/SiO2/Si substrate to film thickness of 500-800 nm at particle concentrations of 0-25.1 mol%, and annealed at various temperatures. Seeding of BST particles prevented the formation of pyrochlore phases, which appeared at temperatures above 400 deg. C in unseeded PZT films, and induced crystallization of PZT into perovskite structures at 420 deg. C, which was more than 100 deg. C below the crystallization temperature of the unseeded PZT films. Measurement of dielectric properties at 1 kHz showed that the 25.1 mol% BST-seeded PZT films annealed at 450 deg. C had a dielectric constant as high as 300 with a dissipation factor of 0.05. Leakage current density of the film was less than 1x10-6 A/cm2 at applied electric field from 0 to 64 kV/cm

  16. Sulfated compounds from marine organisms.

    Science.gov (United States)

    Kornprobst, J M; Sallenave, C; Barnathan, G

    1998-01-01

    More than 500 sulfated compounds have been isolated from marine organisms so far but most of them originate from two phyla only, Spongia and Echinodermata. The sulfated compounds are presented according to the phyla they have been identified from and to their chemical structures. Biological activities, when available, are also given. Macromolecules have also been included in this review but without structural details. PMID:9530808

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    1972-01-01

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

  19. Electromagnetic properties of photodefinable barium ferrite polymer composites

    Directory of Open Access Journals (Sweden)

    Olusegun Sholiyi

    2014-07-01

    Full Text Available This article reports the magnetic and microwave properties of a Barium ferrite powder suspended in a polymer matrix. The sizes for Barium hexaferrite powder are 3–6 μm for coarse and 0.8–1.0 μm for the fine powder. Ratios 1:1 and 3:1 (by mass of ferrite to SU8 samples were characterized and analyzed for predicting the necessary combinations of these powders with SU8 2000 Negative photoresist. The magnetization properties of these materials were equally determined and were analyzed using Vibrating Sample Magnetometer (VSM. The Thru, Reflect, Line (TRL calibration technique was employed in determining complex relative permittivity and permeability of the powders and composites with SU8 between 26.5 and 40 GHz.

  20. Barium titanate nanoparticles: promising multitasking vectors in nanomedicine

    Science.gov (United States)

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

    2016-06-01

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

  1. Thermophysical properties of americium-containing barium plutonate

    International Nuclear Information System (INIS)

    Polycrystalline specimens of americium-containing barium plutonate have been prepared by mixing the appropriate amounts of (Pu0.91Am0.09)O2 and BaCO3 powders followed by reacting and sintering at 1600 K under the flowing gas atmosphere of dry-air. The sintered specimens had a single phase of orthorhombic perovskite structure and were crack-free. Elastic moduli were determined from longitudinal and shear sound velocities. Debye temperature was also determined from sound velocities and lattice parameter measurements. Thermal conductivity was calculated from measured density at room temperature, literature values of heat capacity and thermal diffusivity measured by laser flash method in vacuum. Thermal conductivity of americium-containing barium plutonate was roughly independent of temperature and registered almost the same magnitude as that of BaPuO3 and BaUO3. (author)

  2. Barium titanate nanoparticles: promising multitasking vectors in nanomedicine.

    Science.gov (United States)

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

    2016-06-10

    Ceramic materials based on perovskite-like oxides have traditionally been the object of intense interest for their applicability in electrical and electronic devices. Due to its high dielectric constant and piezoelectric features, barium titanate (BaTiO3) is probably one of the most studied compounds of this family. Recently, an increasing number of studies have been focused on the exploitation of barium titanate nanoparticles (BTNPs) in the biomedical field, owing to the high biocompatibility of BTNPs and their peculiar non-linear optical properties that have encouraged their use as nanocarriers for drug delivery and as label-free imaging probes. In this review, we summarize all the recent findings about these 'smart' nanoparticles, including the latest, most promising potential as nanotransducers for cell stimulation. PMID:27145888

  3. Role of intensive milling in the processing of barium ferrite/magnetite/iron hybrid magnetic nano-composites via partial reduction of barium ferrite

    International Nuclear Information System (INIS)

    In this research a mixture of barium ferrite and graphite was milled for different periods of time and then heat treated at different temperatures. The effects of milling time and heat treatment temperature on the phase composition, thermal behavior, morphology and magnetic properties of the samples have been investigated using X-ray diffraction, differential thermal analysis, high resolution transmission electron microscopy and vibrating sample magnetometer techniques, respectively. X-ray diffraction results revealed that BaFe12O19/Fe3O4 nanocomposites form after a 20 h milling due to the partial reduction of BaFe12O19. High resolution transmission electron microscope images of a 40 h milled sample showed agglomerated structure consisting of nanoparticles with a mean particle size of 30 nm. Thermal analysis of the samples via differential thermal analysis indicated that for un-milled samples, heat treatment up to 900 °C did not result in α-Fe formation, while for a 20 h milled sample heat treatment at 700 °C resulted in reduction process progress to the formation of α-Fe. Wustite was disappeared in an X-ray diffraction pattern of a heat treated sample at 850 °C, by increasing the milling time from 20 to 40 h. By increasing the milling time, the structure of heat treated samples becomes magnetically softer due to an increase in saturation magnetization and a decrease in coercivity. Saturation magnetization and coercivity of a sample milled for 20 h and heat treated at 850 °C were 126.3 emu/g and 149.5 Oe which by increasing the milling time to 40 h, alter to 169.1 emu/g and 24.3 Oe, respectively. High coercivity values of milled and heat treated samples were attributed to the nano-scale formed iron particles. - Graphical abstract: Display Omitted - Highlights: • Barium ferrite and graphite were treated mechano-thermally. • Increasing milling time increases reduction progress after heat treatment. • Composites including iron nano-crystals forms by

  4. 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

    Energy Technology Data Exchange (ETDEWEB)

    Dullin, Christian, E-mail: christian.dullin@med.uni-goettingen.de [University Medical Center Göttingen, Robert Koch Strasse 40, 37075 Göttingen (Germany); Monego, Simeone dal [Cluster in Biomedicine, AREA Science Park Basovizza, Trieste (Italy); Larsson, Emanuel [Elettra Sincrotrone Trieste, Strada Statale 14, km 163.5 in AREA Science Park, 34149 Basovizza (Trieste) (Italy); University of Trieste, Trieste (Italy); Linköping University, SE-581 83 Linkoeping (Sweden); Mohammadi, Sara [Elettra Sincrotrone Trieste, Strada Statale 14, km 163.5 in AREA Science Park, 34149 Basovizza (Trieste) (Italy); Krenkel, Martin [University of Göttingen, Göttingen (Germany); Garrovo, Chiara; Biffi, Stefania [IRCCS Burlo Garofolo, Trieste (Italy); Lorenzon, Andrea [Cluster in Biomedicine, AREA Science Park Basovizza, Trieste (Italy); Markus, Andrea [University Medical Center Göttingen, Robert Koch Strasse 40, 37075 Göttingen (Germany); Napp, Joanna [University Medical Center Göttingen, Robert Koch Strasse 40, 37075 Göttingen (Germany); Max Planck Institute for Experimental Medicine, Hermann-Rein-Strasse 3, 37075 Göttingen (Germany); University Medical Center Göttingen, Robert Koch Strasse 40, 37075 Göttingen (Germany); Salditt, Tim [University of Göttingen, Göttingen (Germany); Accardo, Agostino [University of Trieste, Trieste (Italy); Alves, Frauke [University Medical Center Göttingen, Robert Koch Strasse 40, 37075 Göttingen (Germany); Max Planck Institute for Experimental Medicine, Hermann-Rein-Strasse 3, 37075 Göttingen (Germany); University Medical Center Göttingen, Robert Koch Strasse 40, 37075 Göttingen (Germany); Tromba, Giuliana [Elettra Sincrotrone Trieste, Strada Statale 14, km 163.5 in AREA Science Park, 34149 Basovizza (Trieste) (Italy)

    2015-01-01

    This study presents an approach to increase the sensitivity of lung computed tomography (CT) imaging by utilizing in-line phase contrast CT in combination with single-distance phase-retrieval algorithms and a dedicated image-processing regime. As demonstrated here, functional CT imaging can be achieved for the assessment of both structural alterations in asthmatic mouse lung tissue and the accumulation pattern of instilled barium-sulfate-labelled macrophages in comparison with healthy controls. 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.

  5. 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

    International Nuclear Information System (INIS)

    This study presents an approach to increase the sensitivity of lung computed tomography (CT) imaging by utilizing in-line phase contrast CT in combination with single-distance phase-retrieval algorithms and a dedicated image-processing regime. As demonstrated here, functional CT imaging can be achieved for the assessment of both structural alterations in asthmatic mouse lung tissue and the accumulation pattern of instilled barium-sulfate-labelled macrophages in comparison with healthy controls. 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

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

    Science.gov (United States)

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

    2016-05-10

    Here we report the synthesis, mechanism of formation, characterization and thermal decomposition of new barium borohydride chlorides prepared by mechanochemistry and thermal treatment of MBH4-BaCl2, M = Li, Na or K in ratios 1 : 1 and 1 : 2. Initially, orthorhombic barium chloride, o-BaCl2 transforms into o-Ba(BH4)xCl2-x, x ∼ 0.15. Excess LiBH4 leads to continued anion substitution and a phase transformation into hexagonal barium borohydride chloride h-Ba(BH4)xCl2-x, which accommodates higher amounts of borohydride, possibly x ∼ 0.85 and resembles h-BaCl2. Thus, two solid solutions are in equilibrium during mechano-chemical treatment of LiBH4-BaCl2 (1 : 1) whereas LiBH4-BaCl2 (2 : 1) converts to h-Ba(BH4)0.85Cl1.15. Upon thermal treatment at T > ∼200 °C, h-Ba(BH4)0.85Cl1.15 transforms into another orthorhombic barium borohydride chloride compound, o-Ba(BH4)0.85Cl1.15, which is structurally similar to o-BaBr2. The samples with M = Na and K have lower reactivity and form o-Ba(BH4)xCl2-x, x ∼ 0.1 and a solid solution of sodium chloride dissolved in solid sodium borohydride, Na(BH4)1-xClx, x = 0.07. The new compounds and reaction mechanisms are investigated by in situ synchrotron radiation powder X-ray diffraction (SR-PXD), Fourier transform infrared spectroscopy (FT-IR) and simultaneous thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), mass spectroscopy (MS) and temperature programmed photographic analysis (TPPA). PMID:27109871

  7. Thermoelectric power of barium up to 8 GPa

    Energy Technology Data Exchange (ETDEWEB)

    Ramani, G.; Divakar, C.; Singh, A.K.

    1987-01-15

    The present measurements indicate that the thermoelectric power (TEP) of barium at room temperature and pressure is 15 ..mu..V K/sup -1/, and decreases with increasing pressure, reaching about 4 ..mu..V K/sup -1/ just before the bcc..-->..hcp transition. The TEP shows a discontinuous increase at the bcc..-->..hcp transition beyond which it continues to decrease with increasing pressure.

  8. Effect of Silver Coating on Barium Titanium Oxide Nanoparticle Toxicity

    OpenAIRE

    Obregon, Isidro D.; Betts-Obregon, Brandi S.; Yust, Brian; Pedraza, Francisco; Ortiz, Alexandra; Sardar, Dhiraj; Tsin, Andrew T.

    2013-01-01

    Nanoparticles are presently being studied for optical and biomedical applications such as medical imaging and drug delivery. Nanoparticles impact the cellular environment due to many variables such as size, shape, and composition. How these factors affect cell viability is not fully understood. The purpose of this study is to test the toxicity effects of silver coating (Ag@) Barium Titanium Oxide (BaTiO3) nanoparticles on Rhesus Monkey Retinal Endothelial cells (RhREC’s) in culture. The addit...

  9. Dielectric Properties of Barium Titanate Prepared by Spark Plasma Sintering

    Czech Academy of Sciences Publication Activity Database

    Ctibor, Pavel; Sedláček, J.; Dopita, M.; Pala, Zdeněk

    Bratislava: Slovak Expert Group of Solid State Chemistry and Physics , 2011 - (Koman, M.; Mikloš, D.), s. 68-69 ISBN 978-80-8134-002-4. [Joint Seminar – Development of materials science in research and education (DMRSE)/21.th./. Kežmarské Žlaby (SK), 29.08.2011-02.09.2011] Institutional research plan: CEZ:AV0Z20430508 Keywords : spark plasma sintering * barium titanate * dielectric properties Subject RIV: JK - Corrosion ; Surface Treatment of Materials

  10. Microwave-hydrothermal synthesis of barium strontium titanate nanoparticles

    International Nuclear Information System (INIS)

    Research highlights: → Barium strontium titanate nanoparticles were obtained by the Hydrothemal microwave technique (HTMW) → This is a genuine technique to obtain nanoparticles at low temperature and short times → Barium strontium titanate free of carbonates with tetragonal structure was grown at 130 oC. - Abstract: Hydrothermal-microwave method (HTMW) was used to synthesize crystalline barium strontium titanate (Ba0.8Sr0.2TiO3) nanoparticles (BST) in the temperature range of 100-130 oC. The crystallization of BST with tetragonal structure was reached at all the synthesis temperatures along with the formation of BaCO3 as a minor impurity at lower syntheses temperatures. Typical FT-IR spectra for tetragonal (BST) nanoparticles presented well defined bands, indicating a substantial short-range order in the system. TG-DTA analyses confirmed the presence of lattice OH- groups, commonly found in materials obtained by HTMW process. FE/SEM revealed that lower syntheses temperatures led to a morphology that consisted of uniform grains while higher syntheses temperature consisted of big grains isolated and embedded in a matrix of small grains. TEM has shown BST nanoparticles with diameters between 40 and 80 nm. These results show that the HTMW synthesis route is rapid, cost effective, and could serve as an alternative to obtain BST nanoparticles.

  11. Role of hexadecapole interaction in proton rich barium isotopes

    International Nuclear Information System (INIS)

    From the systematic analysis of the experimental data on proton rich barium isotopes, it is observed that nuclei in the region z ≥ 50 and N≤82 are the transitional nuclei as they show a shape transition from spherical to deformed shape. An interesting feature of the observed yrast spectra in barium isotopic mass chain is the systematic variation of E2+, E4+ and E6+ excitation energy states from 120Ba to 136Ba. It is observed that these states follow a systematic decreasing trend as move away from 136Ba towards 120Ba. The isotopes 120-128Ba can be taken to be quasi-deformed nuclei having E4+/E2+ ratio larger than 2.7. Based on the systematics of low-lying states and the experimental data of quadrupole moments and B(E2) transition probabilities, the stable barium isotopes range from the approximately spherical 138Ba to l30Ba which is close to the deformed 120-128Ba isotopes. The purpose of the paper is to determine the importance of octupole-octupole and hexadecapole- hexadecapole parts of the two body interaction in reproducing the observed nuclear structure properties of 120-136Ba isotopes

  12. CT and barium features of gastrointestinal and peritoneal tuberculosis

    Directory of Open Access Journals (Sweden)

    Makanjuola Dorothy

    1997-01-01

    Full Text Available The radiological features in barium gastrointestinal studies and computed tomographic (CT examinations of 22 consecutive cases of proven peritoneal and/or intestinal tuberculosis were analyzed in order to highlight the radiological features which could provide ready identification of the disease. There were 15 cases of intestinal tuberculosis and 7 cases of peritoneal tuberculosis and 3 patients had both. The commonest location of intestinal tuberculosis was the ileocecal region (N=10 which occurred in association with colonic or ilea] disease. Bowel wall thickening in CT was largely asymmetrical but minimal and symmetrical wall thickening occurred with peritonitis. Luminal narrowing with or without mucosal tethering were seen in both CT and Barium studies. Peritoneal TB had either high density ascites with smudge or nodular omental surface with a thickened omental lining. Also detected was fibrinous dry peritonitis with thickened mesenteric tissue. Lymphadenopathy in the peripancreatic, mesenteric or paracaval were common to both intestinal or peritoneal tuberculosis (21 out of 22. Fifty percent of the patients showed some lymph nodes with necrotic centers. The differential diagnosis included malignant peritonitis and intestinal or mesenteric carcinoid. The study shows that a combination of barium gastrointestinal study and computed tomography can provide distinct features which could strongly suggest the diagnosis of intestinal or peritoneal tuberculosis.

  13. Scanning electron and tunneling microscopy of palladium-barium emitters

    International Nuclear Information System (INIS)

    The results of study of metal-alloyed palladium-barium emitters' of modern very high frequency high-powered electronic vacuum tubes by scanning electron microscopy (SEM) and scanning tunneling microscopy/spectroscopy (STM/STS) are presented. Since the Pd/Ba foil surface is fairly smooth and is not oxidized in air STM/STS investigations are carried out in air in normal laboratory environment. SEM and STM images show that the emitter surface has a complex porous structure. The cathode surface study by STS in tunneling gap modulation mode allowed to take a map of phase distribution with various work function values and high lateral resolution. Obtained images demonstrate the presence of three phases on the Pd/Ba emitter surface, viz. barium-oxygen compounds, intermetallic, and palladium. As it is seen from presented STS image the phase with a low work function value (barium oxides) is concentrated along boundaries of the substance inclusions with work function corresponding to the intemetallic compound Pd5Ba. This supports the model of low work function areas obtained via Ba segregation from the intermetallic compound and oxidation. The presented methods may be used in the Pd/Ba cathode manufacturing process for increasing the yield of electronic devices in microwave tube production and optimize the emitters' characteristics

  14. Early colon cancer : findings on double contrast barium enema

    International Nuclear Information System (INIS)

    The purpose of this study is to describe the radiologic findings of early colon cancer on double-contrast barium enema. We retrospectively reviewed the double-contrast barium enemas of eight patients (M:F = 6:2; mean age : 67 yrs; range : 48-77 yrs) who were pathologically proven to be early colon cancer. The location, size and gross morphology of lesions was evaluated using double-contrast barium enema, while depth of invasion, degree of differentiation, precancerous lesions and lymph node metastasis were evaluated histopathologically. Early colon cancer was found in the rectum (n=4), sigmoid colon (n=3) and ascending colon (n=1). The size of mass ranged from 2.3 ∼ 8.3 (mean, 4.6) cm. And the polypoid type was most common (n=7); this was subdivided into sessile (Is, n=5), semipedunculated (Isp, n=1) and pedunculated type (Ip, n=1). Another mass was a sessile polypoid combined with a flat depressed lesion. In eight cases, four cancers were confined to the mucosa, while the remaining four had infiltrated the submucosa. Most cancers arose from villous and villotubular adenoma. All cases were well-differentiated adenocarcinoma and no metastasis to lymph nodes had occurred. In early colon cancer, lesions were mainly polypoid and large. Most arose from villous and villotubular adenoma. (author). 19 refs., 1 tab., 3 figs

  15. Bioengineered heparins and heparan sulfates.

    Science.gov (United States)

    Fu, Li; Suflita, Matthew; Linhardt, Robert J

    2016-02-01

    Heparin and heparan sulfates are closely related linear anionic polysaccharides, called glycosaminoglycans, which exhibit a number of important biological and pharmacological activities. These polysaccharides, having complex structures and polydispersity, are biosynthesized in the Golgi of animal cells. While heparan sulfate is a widely distributed membrane and extracellular glycosaminoglycan, heparin is found primarily intracellularly in the granules of mast cells. While heparin has historically received most of the scientific attention for its anticoagulant activity, interest has steadily grown in the multi-faceted role heparan sulfate plays in normal and pathophysiology. The chemical synthesis of these glycosaminoglycans is largely precluded by their structural complexity. Today, we depend on livestock animal tissues for the isolation and the annual commercial production of hundred ton quantities of heparin used in the manufacture of anticoagulant drugs and medical device coatings. The variability of animal-sourced heparin and heparan sulfates, their inherent impurities, the limited availability of source tissues, the poor control of these source materials and their manufacturing processes, suggest a need for new approaches for their production. Over the past decade there have been major efforts in the biotechnological production of these glycosaminoglycans, driven by both therapeutic applications and as probes to study their natural functions. This review focuses on the complex biology of these glycosaminoglycans in human health and disease, and the use of recombinant technology in the chemoenzymatic synthesis and metabolic engineering of heparin and heparan sulfates. PMID:26555370

  16. Simplified assessment of segmental gastrointestinal transit time with orally small amount of barium

    International Nuclear Information System (INIS)

    Objective: To determine the effectiveness and advantage of small amount of barium in the measurement of gastrointestinal transmission function in comparison with radio-opaque pallets. Methods: Protocal 1: 8 healthy volunteers (male 6, female 2) with average age 40 ± 6.1 were subjected to the examination of radio-opaque pellets and small amount of barium with the interval of 1 week. Protocol 2: 30 healthy volunteers in group 1 (male 8, female 22) with average age 42.5 ± 8.1 and 50 patients with chronic functional constipation in group 2 (male 11, female 39) with average age 45.7 ± 7.8 were subjected to the small amount of barium examination. The small amount of barium was made by 30 g barium dissolved in 200 ml breakfast. After taking breakfast which contains barium, objectives were followed with abdominal X-ray at 4, 8, 12, 24, 48, 72, 96 h until the barium was evacuated totally. Results: Small amount of barium presented actual chyme or stool transit. The transit time of radio-opaque pallets through the whole gastrointestinal tract was significantly shorter than that of barium (37 ± 8 h vs. 47 ± 10 h, P < 0.05) in healthy people. The transit times of barium in constipation patients were markedly prolonged in colon (61.1 ± 22 vs. 37.3 ± 11, P < 0.01) and rectum (10.8 ± 3.7 vs. 2.3 ± 0.8 h, P < 0.01) compared with unconstipated volunteers. Transit times in individual gastrointestinal segments were also recorded by using small amount of barium, which allowed identifying the subtypes of constipation. Conclusion: The small amount barium examination is a convenient and low cost method to provide the most useful and reliable information on the transmission function of different gastrointestinal segments and able to classify the subtypes of slow transit constipation

  17. Effect of dispersant on preparation of barium-strontium titanate powders through oxalate co-precipitation method

    International Nuclear Information System (INIS)

    The quantitative precipitation of barium-strontium titanyl oxalate: (Ba0.6Sr0.4TiO(C2O4)2.4H2O, BSTO) precursor powders were successfully prepared through oxalate co-precipitation method. The pyrolysis of BSTO at 800 deg. C/4 h produced the barium-strontium titanate (Ba0.6Sr0.4TiO3, BST) powders. Two kinds of dispersants namely ammonium salt of poly mathacrylic acid (PMAA-NH4) and polyethylene glycol (PEG) were added respectively during the co-precipitation procedure. The powders were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), etc. Experimental results show that the addition of the dispersants reduced the productive rate of BST powders. The BSTO and BST powders obtained by aforementioned technique without dispersants were homogeneous with quasi-orbicular morphology. The particles grew into spindle shape with the effect of PEG. The morphology homogeneity was broke with small grains as well as large agglomerated particles concurrent when PMAA-NH4 was added. The mechanism of the effect of the two dispersants was investigated in detail

  18. Barium and Tc-poor S stars: Binary masqueraders among carbon stars

    OpenAIRE

    Jorissen, A; Van Eck, S.

    1997-01-01

    The current understanding of the origin of barium and S stars is reviewed, based on new orbital elements and binary frequencies. The following questions are addressed: (i) Is binarity a necessary condition to produce a barium star? (ii) What is the mass transfer mode (wind accretion or RLOF?) responsible for their formation? (iii) Do barium stars form as dwarfs or as giants? (iv) Do barium stars evolve into Tc-poor S stars? (v) What is the relative frequency of Tc-rich and Tc-poor S stars?

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

    Science.gov (United States)

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

    1984-03-01

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

  20. Barium can replace calcium in calmodulin-dependent contractions of skinned renal arteries of the rabbit.

    Science.gov (United States)

    Kreye, V A; Hofmann, F; Mühleisen, M

    1986-03-01

    Renal arteries of the rabbit were chemically skinned using Triton X-100. In EGTA-buffered solutions containing calmodulin and ATP, small strips of the skinned preparations were found to develop contractile force which was dependent on the concentrations of either free calcium or of free barium. However, a 220 times greater concentration of barium than of calcium was necessary for comparable effects. Quantitatively, the response to barium was dependent on the concentration of calmodulin added to the test solutions. The contractile effect of barium was partly antagonized by the calmodulin antagonist, trifluoperazine. PMID:3960707

  1. High Resolution Computed Tomography Appearences of late sequelae of Barium Aspiration in an asymptomatic young child

    International Nuclear Information System (INIS)

    Barium aspiration is a well-known complication of upper gastro-intestinal studies. Consequences of aspiration are generally insignificant and leave no permanent changes in the lung parenchyma. However, large quantities of high density barium, if aspirated, lead to silent interstitial changes and fibrosis. High-resolution computed tomography HRCT appearances of lung changes have been demonstrated in adults; few such reports are available in the pediatric literature. We report a case of a child who aspirated barium 3 months before this presentation. The HRCT appearances of barium aspiration are presented with a review of the literature. (author)

  2. Tris(diisopropylammonium hydrogensulfate sulfate

    Directory of Open Access Journals (Sweden)

    Gholamhossein Sh. Mohammadnezhad

    2008-08-01

    Full Text Available The cations and anions of the title salt, 3C6H16N+·HSO4−·SO42−, are linked by N—H...O and O—H...O hydrogen bonds into a three-dimensional network. The hydrogensulfate ion, with a single S—O(H bond of 1.563 (2 Å, forms a short O—H...O hydrogen bond [O...O = 2.609 (2 Å] to the sulfate ion. The hydrogensulfate ion accepts two hydrogen bonds from two cations, whereas the sulfate ion, as an acceptor, binds to four cations. The sulfate ion is disordered approximately equally over two sites related by rotation around one of the O—S bonds.

  3. Suppression of the exaggerated growth of barium ferrite nanoparticles from solution using a partial substitution of Sc3+ for Fe3+

    International Nuclear Information System (INIS)

    The effect of the substitution of Sc3+ for Fe3+ in barium ferrite on the size of the resulting nanoparticles was studied. These nanoparticles, with the nominal compositions BaFe12O19 and BaFe11.5Sc0.5O19, were synthesized hydrothermally at 90–240 °C or by coprecipitation under reflux at 140 °C. The precursors were obtained using (co)precipitation at room temperature. The sizes and morphologies of the precursors and nanoparticles were inspected with transmission electron microscopy, while their structures were confirmed with a combination of X-ray powder and electron diffraction. The samples’ compositions were analyzed with energy-dispersive X-ray spectroscopy. The evolution of the particle size and its distribution with the synthesis temperature and time were studied in pure and Sc-substituted barium ferrite and correlated with the evolution of the magnetic properties. The Sc substitution in the barium ferrite results in the formation of magnetic nanoparticles with applicable magnetic properties and in a significant reduction of the exaggerated particle growth. This was explained on the basis of the reaction kinetics

  4. Suppression of the exaggerated growth of barium ferrite nanoparticles from solution using a partial substitution of Sc{sup 3+} for Fe{sup 3+}

    Energy Technology Data Exchange (ETDEWEB)

    Lisjak, Darja, E-mail: darja.lisjak@ijs.si; Bukovec, Mitja [Jožef Stefan Institute, Department for Materials Synthesis (Slovenia); Zupan, Klementina [University of Ljubljana, Faculty for Chemistry and Chemical Technology (Slovenia)

    2016-02-15

    The effect of the substitution of Sc{sup 3+} for Fe{sup 3+} in barium ferrite on the size of the resulting nanoparticles was studied. These nanoparticles, with the nominal compositions BaFe{sub 12}O{sub 19} and BaFe{sub 11.5}Sc{sub 0.5}O{sub 19}, were synthesized hydrothermally at 90–240 °C or by coprecipitation under reflux at 140 °C. The precursors were obtained using (co)precipitation at room temperature. The sizes and morphologies of the precursors and nanoparticles were inspected with transmission electron microscopy, while their structures were confirmed with a combination of X-ray powder and electron diffraction. The samples’ compositions were analyzed with energy-dispersive X-ray spectroscopy. The evolution of the particle size and its distribution with the synthesis temperature and time were studied in pure and Sc-substituted barium ferrite and correlated with the evolution of the magnetic properties. The Sc substitution in the barium ferrite results in the formation of magnetic nanoparticles with applicable magnetic properties and in a significant reduction of the exaggerated particle growth. This was explained on the basis of the reaction kinetics.

  5. Influence of La-Co substitution on the structure and magnetic properties of low-temperature sintered M-type barium ferrites

    Institute of Scientific and Technical Information of China (English)

    李颉; 张怀武; 李强; 李元勋; 郁国良

    2013-01-01

    La-Co substituted M-type barium ferrites (BaM) were prepared by traditional solid state method and sintered at low tem-perature (1173 K). X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM) were employed to investigate the influence of La-Co on the structure and magnetic properties of the samples. By sintering at 1173 K for 6 h in air, single phase M-type barium ferrites with chemical composition of Ba(LaCo)xFe12-2xO19 (x=0.0-0.5) were formed. M-H curves showed that the magnetic properties of barium ferrites were obviously effected by La-Co substitution. The saturation magnetization (Ms) and coercivity (Hc) reached the maximum value of 65.15 Am2/kg and 4165 Oe, respectively. This behavior was attributed to the sites of La-Co substitutions and the particles size. SEM revealed that the shape of ferrite particles was influenced by La-Co substitution.

  6. Study on Suface Modification of Barium Carbonate Powders with Stearic Acid%硬脂酸对碳酸钡表面改性的研究

    Institute of Scientific and Technical Information of China (English)

    刘铭; 霍冀川; 刘树信

    2011-01-01

    采用硬脂酸对碳酸钡进行表面改性,研究改性剂用量、改性温度和改性时间等因素对碳酸钡表面改性的影响.采用粒度分析、红外光谱、热重分析、扫描电镜、X射线衍射及润湿性实验对改性前后的碳酸钡进行表征.结果表明:在硬脂酸用量为1.5%(质量分数),改性温度为80℃,改性时间为30 min的条件下制备的产品性能优良,活化指数达99.2%.碳酸钡经硬脂酸改性后,粒度由4.56 μm减小至4.19 μm;硬脂酸在碳酸钡表面发生吸附键合,形成新的化学键;改性后的碳酸钡表面性质由亲水变为疏水.%The surface modification of barium carbonate powders by stearic acid was investigated. The impact of modifier dosage, modification temperature and modification time on the surface modification of barium carbonate powders were studied. The unmodified and modified barium carbonate were both tested with the particle size distribution, FTIR, TG-DSC, SEM, XRD and the experiments of wettability. The results showed that the products with excellent modification effect as well as 99.2% activation exponential were prepared in the conditions of 80 ℃, with 1.5% stearic acid added (mass fraction) and stirring for 30 min. The particle size of barium carbonate reduced from 4.56 u.m to 4.19 μm. The stearic acid molecules occurred adsorbing bond on the surface of barium carbonate, forming new chemical bonds, and the surface property of barium carbonatemodified with stearic acid was changed from hydrophilicity tohydrophobicity.

  7. Nanofibers obtained by electrospinning of BaTiO3 particles dispersed in polyvinyl alcohol and ethylcellulose

    Energy Technology Data Exchange (ETDEWEB)

    Avila, Humar A.; Reboredo, Maria M.; Castro, Miriam; Parra, Rodrigo, E-mail: havila@fi.mdp.edu.ar [Instituto de Investigaciones en Ciencia y Tecnologia de Materiales - INTEMA, Consejo Nacional de Investigaciones Cientificas y Tecnicas - CONICET, Universidad Nacional de Mar del Plata - UNMdP, Mar del Plata (Argentina)

    2013-11-01

    Barium titanate particles (100-300 nm) synthesized by hydrothermal method were dispersed in both polyvinyl alcohol (PVA) and ethylcellulose (EC) solutions. These suspensions were processed by electrospinning. When no particles were added, homogeneous polymeric nanofibers were obtained. Under certain conditions, polymeric suspensions of barium titanate particles were electrospun generating polymeric fibers with BT particles. The effect of a surfactant was also assessed over the formation of nanofibers. The BaTiO{sub 3} particles synthesized by hydrothermal method were characterized by X-Ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and Raman spectroscopy. Fibers were characterized by scanning electron microscopy (SEM). (author)

  8. Sulfate reduction in freshwater peatlands

    International Nuclear Information System (INIS)

    This text consist of two parts: Part A is a literature review on microbial sulfate reduction with emphasis on freshwater peatlands, and part B presents the results from a study of the relative importance of sulfate reduction and methane formation for the anaerobic decomposition in a boreal peatland. The relative importance of sulfate reduction and methane production for the anaerobic decomposition was studied in a small raised bog situated in the boreal zone of southern Sweden. Depth distribution of sulfate reduction- and methane production rates were measured in peat sampled from three sites (A, B, and C) forming an minerotrophic-ombrotrophic gradient. SO42- concentrations in the three profiles were of equal magnitude and ranged from 50 to 150 μM. In contrast, rates of sulfate reduction were vastly different: Maximum rates in the three profiles were obtained at a depth of ca. 20 cm below the water table. In A it was 8 μM h-1 while in B and C they were 1 and 0.05 μM h-1, respectively. Methane production rates, however, were more uniform across the three nutrient regimes. Maximum rates in A (ca. 1.5 μg d-1 g-1) were found 10 cm below the water table, in B (ca. 1.0 μg d-1 g-1) in the vicinity of the water table, and in C (0.75 μg d-1 g-1) 20 cm below the water table. In all profiles both sulfate reduction and methane production rates were negligible above the water table. The areal estimates of methane production for the profiles were 22.4, 9.0 and 6.4 mmol m-2 d-1, while the estimates for sulfate reduction were 26.4, 2.5, and 0.1 mmol m-2 d-1, respectively. The calculated turnover times at the sites were 1.2, 14.2, and 198.7 days, respectively. The study shows that sulfate reducing bacteria are important for the anaerobic degradation in the studied peatland, especially in the minerotrophic sites, while methanogenic bacteria dominate in ombrotrophic sites Examination paper. 67 refs, 6 figs, 3 tabs

  9. Acid Sulfate Alteration on Mars

    Science.gov (United States)

    Ming, D. W.; Morris, R. V.

    2016-01-01

    A variety of mineralogical and geochemical indicators for aqueous alteration on Mars have been identified by a combination of surface and orbital robotic missions, telescopic observations, characterization of Martian meteorites, and laboratory and terrestrial analog studies. Acid sulfate alteration has been identified at all three landing sites visited by NASA rover missions (Spirit, Opportunity, and Curiosity). Spirit landed in Gusev crater in 2004 and discovered Fe-sulfates and materials that have been extensively leached by acid sulfate solutions. Opportunity landing on the plains of Meridiani Planum also in 2004 where the rover encountered large abundances of jarosite and hematite in sedimentary rocks. Curiosity landed in Gale crater in 2012 and has characterized fluvial, deltaic, and lacustrine sediments. Jarosite and hematite were discovered in some of the lacustrine sediments. The high elemental abundance of sulfur in surface materials is obvious evidence that sulfate has played a major role in aqueous processes at all landing sites on Mars. The sulfate-rich outcrop at Meridiani Planum has an SO3 content of up to 25 wt.%. The interiors of rocks and outcrops on the Columbia Hills within Gusev crater have up to 8 wt.% SO3. Soils at both sites generally have between 5 to 14 wt.% SO3, and several soils in Gusev crater contain around 30 wt.% SO3. After normalization of major element compositions to a SO3-free basis, the bulk compositions of these materials are basaltic, with a few exceptions in Gusev crater and in lacustrine mudstones in Gale crater. These observations suggest that materials encountered by the rovers were derived from basaltic precursors by acid sulfate alteration under nearly isochemical conditions (i.e., minimal leaching). There are several cases, however, where acid sulfate alteration minerals (jarosite and hematite) formed in open hydrologic systems, e.g., in Gale crater lacustrine mudstones. Several hypotheses have been suggested for the

  10. Impacts of Sulfate Seed Acidity and Water Content on Isoprene Secondary Organic Aerosol Formation.

    Science.gov (United States)

    Wong, Jenny P S; Lee, Alex K Y; Abbatt, Jonathan P D

    2015-11-17

    The effects of particle-phase water and the acidity of pre-existing sulfate seed particles on the formation of isoprene secondary organic aerosol (SOA) was investigated. SOA was generated from the photo-oxidation of isoprene in a flow tube reactor at 70% relative humidity (RH) and room temperature in the presence of three different sulfate seeds (effloresced and deliquesced ammonium sulfate and ammonium bisulfate) under low NOx conditions. High OH exposure conditions lead to little isoprene epoxydiol (IEPOX) SOA being generated. The primary result is that particle-phase water had the largest effect on the amount of SOA formed, with 60% more SOA formation occurring with deliquesced ammonium sulfate seeds as compared to that on effloresced ones. The additional organic material was highly oxidized. Although the amount of SOA formed did not exhibit a dependence on the range of seed particle acidity examined, perhaps because of the low amount of IEPOX SOA, the levels of high-molecular-weight material increased with acidity. While the uptake of organics was partially reversible under drying, the results nevertheless indicate that particle-phase water enhanced the amount of organic aerosol material formed and that the RH cycling of sulfate particles may mediate the extent of isoprene SOA formation in the atmosphere. PMID:26460477

  11. High aerosol acidity despite declining atmospheric sulfate concentrations over the past 15 years

    Science.gov (United States)

    Weber, Rodney J.; Guo, Hongyu; Russell, Armistead G.; Nenes, Athanasios

    2016-04-01

    Particle acidity affects aerosol concentrations, chemical composition and toxicity. Sulfate is often the main acid component of aerosols, and largely determines the acidity of fine particles under 2.5 μm in diameter, PM2.5. Over the past 15 years, atmospheric sulfate concentrations in the southeastern United States have decreased by 70%, whereas ammonia concentrations have been steady. Similar trends are occurring in many regions globally. Aerosol ammonium nitrate concentrations were assumed to increase to compensate for decreasing sulfate, which would result from increasing neutrality. Here we use observed gas and aerosol composition, humidity, and temperature data collected at a rural southeastern US site in June and July 2013 (ref. ), and a thermodynamic model that predicts pH and the gas-particle equilibrium concentrations of inorganic species from the observations to show that PM2.5 at the site is acidic. pH buffering by partitioning of ammonia between the gas and particle phases produced a relatively constant particle pH of 0-2 throughout the 15 years of decreasing atmospheric sulfate concentrations, and little change in particle ammonium nitrate concentrations. We conclude that the reductions in aerosol acidity widely anticipated from sulfur reductions, and expected acidity-related health and climate benefits, are unlikely to occur until atmospheric sulfate concentrations reach near pre-anthropogenic levels.

  12. Solubility and stability of barium arsenate and barium hydrogen arsenate at 25oC

    International Nuclear Information System (INIS)

    The inconsistency among current thermodynamic data of Ba3(AsO4)2(c) and BaHAsO4.H2O(c) led the authors to obtain independent solubility data of barium arsenate by both precipitation and dissolution experiments. Low and neutral pH (3.63-7.43) favored the formation of BaHAsO4.H2O(c). Both BaHAsO4.H2O(c) and Ba3(AsO4)2(c) formed at the neutral pH conditions (7.47, 7.66), whereas Ba3(AsO4)2(c) was the only solid phase precipitated at high pH (13.03, 13.10). The Ba3(AsO4)2(c) precipitate acquired at 50oC appeared as small leafy crystal, while the Ba3(AsO4)2(c) solid precipitated at 25oC comprised granular aggregate with some smaller crystal clusters. XRD and SEM analyses of Ba3(AsO4)2(c) and BaHAsO4.H2O(c) indicated that the solids were indistinguishable before and after the dissolution experiments. In the present work, the solubility products (Ksp) for Ba3(AsO4)2(c) and BaHAsO4.H2O(c) were determined to be 10-23.53(10-23.01 to 10-24.00) and 10-5.60(10-5.23 to 10-5.89), respectively. ΔGfo for Ba3(AsO4)2(c) and BaHAsO4.H2O(c) were calculated to be -3113.40 and -1544.47kJ/mol, respectively. There was no difference between the solubility products of the leafy and the granular Ba3(AsO4)2(c) solids

  13. Sulfated Macromolecules as Templates for Calcite Nucleation and Growth

    Science.gov (United States)

    David, M.; Passalacqua, K.; Neira, A. C.; Fernandez, M. S.

    2003-12-01

    \\{111\\} faces. The addition of the hypersulfated heparin SM induce the formation of large rosette-like aggregated calcite crystals, where the majority of the \\{104\\} faces appeared not to be lost, although aggregation is done by different kind of faces. It is concluded that, the variation of the sulfate and carboxylate content and configuration drastically changed the morphology of the calcite crystals. The production of calcite particles with defined morphologies could be interesting for the design of novel materials with desirable shape- and texture-depending properties. Granted by FONDAP 11980002.

  14. Brittlestars contain highly sulfated chondroitin sulfates/dermatan sulfates that promote fibroblast growth factor 2-induced cell signaling

    OpenAIRE

    Ramachandra, Rashmi; Namburi, Ramesh B; Ortega-Martinez, Olga; Shi, Xiaofeng; Zaia, Joseph; Dupont, Sam T.; Thorndyke, Michael C; Lindahl, Ulf; Spillmann, Dorothe

    2013-01-01

    Glycosaminoglycans (GAGs) isolated from brittlestars, Echinodermata class Ophiuroidea, were characterized, as part of attempts to understand the evolutionary development of these polysaccharides. A population of chondroitin sulfate/dermatan sulfate (CS/DS) chains with a high overall degree of sulfation and hexuronate epimerization was the major GAG found, whereas heparan sulfate (HS) was below detection level. Enzymatic digestion with different chondroitin lyases revealed exceptionally high p...

  15. Reduced Sulfation of Chondroitin Sulfate but Not Heparan Sulfate in Kidneys of Diabetic db/db Mice

    OpenAIRE

    Reine, Trine M.; Grøndahl, Frøy; Jenssen, Trond G.; Hadler-Olsen, Elin; Prydz, Kristian; Kolset, Svein O.

    2013-01-01

    Heparan sulfate proteoglycans are hypothesized to contribute to the filtration barrier in kidney glomeruli and the glycocalyx of endothelial cells. To investigate potential changes in proteoglycans in diabetic kidney, we isolated glycosaminoglycans from kidney cortex from healthy db/+ and diabetic db/db mice. Disaccharide analysis of chondroitin sulfate revealed a significant decrease in the 4-O-sulfated disaccharides (D0a4) from 65% to 40%, whereas 6-O-sulfated disaccharides (D0a6) were redu...

  16. Interaction of small dermatan sulfate proteoglycan from fibroblasts with fibronectin

    OpenAIRE

    1987-01-01

    Immunogold labeling was used to localize the core protein of small dermatan sulfate proteoglycan (DS-PG) on the surface of cultured human fibroblasts. At 4 degrees C, DS-PG core protein was uniformly distributed over the cell surface. At 37 degrees C, gold particles either became rearranged in form of clusters or remained associated with fibrils. Double-label immunocytochemistry indicated the co- distribution of DS-PG core protein and fibronectin in the fibrils. In an enzyme-linked immunosorb...

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

    Science.gov (United States)

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

    2009-06-01

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

  18. FY-15 Progress Report on Cleanup of irradiated SHINE Target Solutions Containing 140g-U/L Uranyl Sulfate

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, Megan E. [Argonne National Lab. (ANL), Argonne, IL (United States); Bowers, Delbert L. [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, George F. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-09-01

    During FY 2012 and 2013, a process was developed to convert the SHINE Target Solution (STS) of irradiated uranyl sulfate (140 g U/L) to uranyl nitrate. This process is necessary so that the uranium solution can be processed by the UREX (Uranium Extraction) separation process, which will remove impurities from the uranium so that it can be recycled. The uranyl sulfate solution must contain <0.02 M SO42- so that the uranium will be extractable into the UREXsolvent. In addition, it is desired that the barium content be below 0.0007 M, as this is the limit in the Resource Conservation and Recovery Act (RCRA).

  19. Status of copper sulfate - 2008

    Science.gov (United States)

    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,...

  20. Sulfate transport in toad skin

    DEFF Research Database (Denmark)

    Larsen, Erik Hviid; Simonsen, K

    1988-01-01

    1. In short-circuited toad skin preparations exposed bilaterally to NaCl-Ringer's containing 1 mM SO2(-4), influx of sulfate was larger than efflux showing that the skin is capable of transporting sulfate actively in an inward direction. 2. This active transport was not abolished by substituting...... apical Na+ for K+. 3. Following voltage activation of the passive Cl- permeability of the mitochondria-rich (m.r.) cells sulfate flux-ratio increased to a value predicted from the Ussing flux-ratio equation for a monovalent anion. 4. In such skins, which were shown to exhibit vanishingly small leakage...... conductances, the variation of the rate coefficient for sulfate influx (y) was positively correlated with the rate coefficient for Cl- influx (x), y = 0.035 x - 0.0077 cm/sec (r = 0.9935, n = 15). 5. Addition of the phosphodiesterase inhibitor, 3-isobutyl-1-methyl-xanthine to the serosal bath of short...

  1. Anion and cation diffusion in barium titanate and strontium titanate

    International Nuclear Information System (INIS)

    Perovskite oxides show various interesting properties providing several technical applications. In many cases the defect chemistry is the key to understand and influence the material's properties. In this work the defect chemistry of barium titanate and strontium titanate is analysed by anion and cation diffusion experiments and subsequent time-of-flight secondary ion mass spectrometry (ToF-SIMS). The reoxidation equation for barium titanate used in multi-layer ceramic capacitors (MLCCs) is found out by a combination of different isotope exchange experiments and the analysis of the resulting tracer diffusion profiles. It is shown that the incorporation of oxygen from water vapour is faster by orders of magnitude than from molecular oxygen. Chemical analysis shows the samples contain various dopants leading to a complex defect chemistry. Dysprosium is the most important dopant, acting partially as a donor and partially as an acceptor in this effectively acceptor-doped material. TEM and EELS analysis show the inhomogeneous distribution of Dy in a core-shell microstructure. The oxygen partial pressure and temperature dependence of the oxygen tracer diffusion coefficients is analysed and explained by the complex defect chemistry of Dy-doped barium titanate. Additional fast diffusion profiles are attributed to fast diffusion along grain boundaries. In addition to the barium titanate ceramics from an important technical application, oxygen diffusion in cubic, nominally undoped BaTiO3 single crystals has been studied by means of 18O2/16O2 isotope exchange annealing and subsequent determination of the isotope profiles in the solid by ToF-SIMS. It is shown that a correct description of the diffusion profiles requires the analysis of the diffusion through the surface space-charge into the material's bulk. Surface exchange coefficients, space-charge potentials and bulk diffusion coefficients are analysed as a function of oxygen partial pressure and temperature. The data

  2. Metabolic Flexibility of Sulfate-Reducing Bacteria

    OpenAIRE

    Plugge, Caroline M.; Zhang, Weiwen; Scholten, Johannes C. M.; Stams, Alfons J. M.

    2011-01-01

    Dissimilatory sulfate-reducing prokaryotes (SRB) are a very diverse group of anaerobic bacteria that are omnipresent in nature and play an imperative role in the global cycling of carbon and sulfur. In anoxic marine sediments sulfate reduction accounts for up to 50% of the entire organic mineralization in coastal and shelf ecosystems where sulfate diffuses several meters deep into the sediment. As a consequence, SRB would be expected in the sulfate-containing upper sediment layers, whereas me...

  3. Sulfate reduction and methanogenesis in marine sediments

    Science.gov (United States)

    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.

  4. Synthesis of Barium Titanate from Titanyl Acylate Precursor by Sol-precipitate Method

    International Nuclear Information System (INIS)

    Nanometersize barium titanates (BaTiO3:BT) powders can be obtained by sol-precipitate method in the presence of polyoxyethylene (20) sorbiton monooleate (Tween-80) as a polymeric surface modifier in a strong alkaline solution (pH > 13). FT-IR, TG/DTA, SEM and XRD were used to investigate the effects of the surfactant influence on the morphology of the obtained BaTiO3 powders. With adding surfactant, a slower rate of hydrolyzation is observed and the rate of condensation is slower. The addition of Tween-80 surfactant in general leads to the formation of smaller particle size of BaTi)3 (70-100 nm). Without adding surfactant, larger particle size of BaTiO3 (100-200 nm) was obtained. The nanometersize BaTiO3 powders were readily sintered at 1000-1200C. Raman-active modes of tetragonal phase BT were detected from Raman spectra of BaTiO3 between 8000C to 12000C.

  5. Structural and magnetic properties of conventional and microwave treated Ni–Zr doped barium strontium hexaferrite

    International Nuclear Information System (INIS)

    Highlights: ► Saturation magnetization increases whereas the coercivity decreases. ► The transition from hard phase to soft phase. ► Therefore, it is used for high-density magnetic recording applications. -- Abstract: M-type hexaferrites of component B0.5Sr0.5Fe12−2xNixZrxO19 were investigated. The XRD patterns show single phase of the magnetoplumbite barium strontium ferrite and no other phases were present. Significant increase in line broadening of the XRD patterns was observed indicating a decrease of grain size. The samples exhibit well defined crystallization; all of them are hexagonal platelet grains. As the substitution level increased x = 0.2–0.8 mol%, the grains are agglomerated and the average diameter increased. The Hc decreases remarkably with increasing Ni and Zr ions content. It was found that the particle size could be effectively decreased and coercivity Hc could easily be controlled by varying the concentration (x) without significantly decreasing saturation magnetization. In particular, Ba0.5Sr0.5Fe12−2xNixZrxO19 with x = 0.2, 0.4, 0.6, 0.8 mol% has suitable magnetic characteristics with particle size small enough for high-density magnetic recording applications.

  6. A Search for the Electron EDM using Europium-Barium Titanates

    Science.gov (United States)

    Eckel, Stephen P.

    The discovery of a permanent electric dipole moment (EDM) of a fundamental particle would prove a great discovery in modern physics; such an EDM would violate two or three of the core symmetries of the fundamental forces of nature. Many models that go beyond the standard model of particle physics produce EDMs with magnitudes approaching the level detectable by the next generation of experiments. One possibility for such an experiment involves the use of a solid sample at low temperatures. In a paramagnetic material, the unpaired electrons, if they possess an EDM, can interact with the polarization of the sample and produce a magnetization that can be detected. This dissertation discusses an incarnation of such an experiment based on mixed europium-barium titanates. Such an experiment offers several advantages over other solid-state and atomic EDM searches including larger electron EDM induced interactions and the ability to measure without an applied electric field. This experiment has produced the world's best limit on the electron EDM to date from a solid sample, at |de| < 6.05 × 10-25 ecm (90% confidence limit). While this limit represents an improvement in the realm of solid-state experiments, it is not yet competitive with similar molecular and atomic experiments. However, there are many possibilities that could produce a superior solid-state experiment, and these will be discussed.

  7. Synthesis and characterization of nickel/barium hexa-aluminate composite coatings

    Indian Academy of Sciences (India)

    Dinesh Kumar; Sampada Gurav; Vikram Jayaram; Sanjay Kumar Biswas

    2012-11-01

    Electrodeposition of nickel/barium hexa-aluminate (Ni/BHA) composite coatings has been carried out from a Watt’s bath on mild steel substrate. BHA powders with plate habit were synthesized by solution combustion synthesis followed by heat treatment to ensure complete conversion to the hexa-aluminate phase. Heat treated material was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) combined with X-ray analysis. The dispersion behaviour and stability of BHA suspensions with cationic and anionic surfactants at room temperature were studied by dynamic light scattering under different pH. The influence of BHA concentration in the electrolytic bath, deposition temperature, pH, current density and duty cycle on particle incorporation in the coatings were studied and conditions for maximum particle incorporation were established. Coatings with a roughness of about 0.4 m were produced by using this technique. Effect of BHA content on microhardness was also investigated. A reasonably good thickness of the coatings was achieved in a given set of conditions.

  8. Oriented nucleation and growth of anhydrite during direct sulfation of limestone

    DEFF Research Database (Denmark)

    Hu, Guilin; Dam-Johansen, Kim; Wedel, Stig

    2008-01-01

    The direct sulfation of limestone (Iceland Spar) was studied at 973 K in a fixed-bed reactor. Scanning electron microscopy examinations of the sulfated limestone particles show that the sulfation process involves oriented nucleation and growth of the solid product, anhydrite. The reason for the...... occurrence of oriented nucleation and growth of the solid product is related to a close two-dimensional lattice match between the lattice plane {1,0,4} of calcite and the lattice plane {(1) over bar ,1,0} of anhydrite....

  9. 75 FR 36629 - Barium Chloride From the People's Republic of China: Continuation of Antidumping Duty Order

    Science.gov (United States)

    2010-06-28

    ... Barium Chloride From China, 75 FR 33824 (June 15, 2010), and Barium Chloride from China (Inv. No. 731-TA... Five-year (``Sunset'') Review, 74 FR 31412 (July 1, 2009). As a result of its review, the Department... China: Final Results of Expedited Third Sunset Review of Antidumping Duty Order, 74 FR 55814 (October...

  10. New efficient catalyst for ammonia synthesis: barium-promoted cobalt on carbon

    DEFF Research Database (Denmark)

    Hagen, Stefan; Barfod, Rasmus; Fehrmann, Rasmus; Jacobsen, Claus J.H.; Teunissen, Herman T; Ståhl, Kenny; Chorkendorff, Ib

    2002-01-01

    Barium-promoted cobalt catalysts supported on carbon exhibit higher ammonia activities at synthesis temperatures than the commercial, multipromoted iron catalyst and also a lower ammonia......Barium-promoted cobalt catalysts supported on carbon exhibit higher ammonia activities at synthesis temperatures than the commercial, multipromoted iron catalyst and also a lower ammonia...

  11. LACK OF EFFECT OF DRINKING WATER BARIUM ON CARDIOVASCULAR RISK FACTORS

    Science.gov (United States)

    Higher cardiovascular mortality has been associated in a single epidemiological study with higher levels of barium in drinking water. he purpose of this study was to determine whether drinking water barium at levels found in some U.S. communities alters the known risk factors for...

  12. Acute respiratory failure caused by aspiration of high density barium: A case report

    International Nuclear Information System (INIS)

    Accidental aspiration of barium contrast medium during the upper gastrointestinal study can occur in patients with swallowing disorder, especially in the elderly patients. We experienced a case of respiratory failure followed by death within a few hours in 85 year-old patient after barium aspiration

  13. 21 CFR 182.1125 - Aluminum sulfate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Aluminum sulfate. 182.1125 Section 182.1125 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR... Substances § 182.1125 Aluminum sulfate. (a) Product. Aluminum sulfate. (b) Conditions of use. This...

  14. 21 CFR 582.1125 - Aluminum sulfate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Aluminum sulfate. 582.1125 Section 582.1125 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1125 Aluminum sulfate. (a) Product. Aluminum sulfate. (b) Conditions of use. This...

  15. 21 CFR 186.1797 - Sodium sulfate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium sulfate. 186.1797 Section 186.1797 Food and... Substances Affirmed as GRAS § 186.1797 Sodium sulfate. (a) Sodium sulfate (Na2SO4, CAS Reg. No. 7757-82-6... crystalline powder. It is prepared by the neutralization of sulfuric acid with sodium hydroxide. (b)...

  16. Sulfate-reducing prokaryotes in river floodplains

    NARCIS (Netherlands)

    Miletto, M.

    2007-01-01

    This thesis constitutes a pioneer attempt at elucidating the ecology of sulfate-reducing prokaryotes in river floodplains. These are non-typical sulfate-reducing environmental settings, given the generally low sulfate concentration that characterize freshwater habitats, and river flow regulation tha

  17. 21 CFR 582.5461 - Manganese sulfate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Manganese sulfate. 582.5461 Section 582.5461 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5461 Manganese sulfate. (a) Product. Manganese sulfate. (b) Conditions of use....

  18. 21 CFR 184.1461 - Manganese sulfate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Manganese sulfate. 184.1461 Section 184.1461 Food... Specific Substances Affirmed as GRAS § 184.1461 Manganese sulfate. (a) Manganese sulfate (MnSO4·H2O, CAS... manganese compounds with sulfuric acid. It is also obtained as a byproduct in the manufacture...

  19. 21 CFR 184.1443 - Magnesium sulfate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Magnesium sulfate. 184.1443 Section 184.1443 Food... Specific Substances Affirmed as GRAS § 184.1443 Magnesium sulfate. (a) Magnesium sulfate (MgSO4·7H2O, CAS... magnesium oxide, hydroxide, or carbonate with sulfuric acid and evaporating the solution to...

  20. 21 CFR 582.5443 - Magnesium sulfate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Magnesium sulfate. 582.5443 Section 582.5443 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5443 Magnesium sulfate. (a) Product. Magnesium sulfate. (b) Conditions of use....

  1. Enhanced flexoelectricity through residual ferroelectricity in barium strontium titanate

    International Nuclear Information System (INIS)

    Residual ferroelectricity is observed in barium strontium titanate ceramics over 30 °C above the global phase transition temperature, in the same temperature range in which anomalously large flexoelectric coefficients are reported. The application of a strain gradient leads to strain gradient-induced poling or flexoelectric poling. This was observed by the development of a remanent polarization in flexoelectric measurements, an induced d33 piezoelectric response even after the strain gradient was removed, and the production of an internal bias of 9 kV m−1. It is concluded that residual ferroelectric response considerably enhances the observed flexoelectric response

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  3. Heterometallic β-diketonates containing barium and rare earth elements

    International Nuclear Information System (INIS)

    Potentiality of formation of heterobimetallic complexes of the composition Ba[LnLn] (Ln = La, Er; L - hexafluoroacetylacetonate, pivaloyltrifluoroacetonate-(Pta), dipivaloylmethanate-anion, is studied by mass spectrometry (MALDI-MS) method. The compounds prepared are characterized by the methods of element analysis. IR spectroscopy of gaseous phase, thermal analysis in vacuum. Compound Ba[La(Pta)5] features increased thermal stability compared with Ba(Pta)2 and La(Pta)3 and it can be offered for practical use as barium and lanthanum source in preparation of oxide films

  4. Mechanism of thermoluminescence in europium-doped barium fluorochloride

    International Nuclear Information System (INIS)

    The paper concerns the optical properties of europium-doped barium fluorochloride. Thermoluminescence (TL) and emission studies have been carried out with this material and the results are reported. The irradiation was by γ-rays from a 60Co source, the dose rate being 5000rad min-1. Glow curves of γ-irradiated BaFCl:Eu2+ are presented, along with the glow curves resolved into component peaks. TL emission spectra of BaFCl:Eu2+ at room temperature, 345K, 395K and 500K are also described. (U.K.)

  5. The Kerr nonlinearity of the beta-barium borate crystal

    OpenAIRE

    Bache, Morten; Guo, Hairun; Zhou, Binbin; Zeng, Xianglong

    2013-01-01

    A popular crystal for ultrafast cascading experiments is beta-barium-borate (β-BaB2O4, BBO). It has a decent quadratic nonlinear coefficient, and because the crystal is anisotropie it can be birefringence phase-matched for type I (oo → e) second-harmonic generation (SHG). For femtosecond experiments BBO is popular because of low dispersion and a high damage threshold. The main attractive property of ultrafast cascading is that the induced cascading nonlinearity nI 2, casc can be negative, i.e...

  6. K-shell fluorescence yields of barium and lanthanum

    International Nuclear Information System (INIS)

    K-shell fluorescence yields for barium and lanthanum have been measured adopting simple 2π geometrical configuration and employing a weak 57Co radioactive source. A scintillation spectrometer with an NaI(Tl) detector of dimensions 44.5 mm diameterx50 mm thickness was employed for the detection and measurement of radiation. The results obtained are in good agreement with the best-fitted values of and also with the other experimental values, indicating that our simple method can be extended to determine fluorescence parameters of high Z materials.

  7. Colloidal stability of aqueous suspensions of barium zirconate

    OpenAIRE

    Boschini, Frédéric; Rulmont, André; Cloots, Rudi; Moreno, R.

    2005-01-01

    In this article, the colloidal behaviour of aqueous suspensions of barium zirconate is investigated. The variation of zeta-potential as a consequence of changing the pH and the concentration of an anionic polyelectrolyte is studied, the isoelectric point occurring at pH 5.3. The IEP shifts down on calcining the powder and also when anionic polyelectrolytes are added. Rheological studies have been made on suspensions prepared to a solids loading of 27 vol.% (72 wt.%). Optimum dispersing condit...

  8. Experiences with Cascara-Salax preparating children for barium enema

    International Nuclear Information System (INIS)

    30 children prepared for barium enema using Cascara-Salax are reported on. The results are: 1. A satisfactory preparation is possible in out-patient children older than ten years. 2. For children aged 6 to 10 years only the half dose early in the afternoon before the X-ray examination is necessary. 3. In most cases the colon is completely clear, if not, the X-ray study is generally not influenced by rests of stool. 4. It should be considered that other - and often unreliable - cleaning manoevers aren't necessary, the Cascara-Salax - method ist time - saving and side-effects are not of value. (orig.)

  9. Bis(chlorido)(dimethyl­sulfoxide-κO)barium(II)

    OpenAIRE

    Gschwind, Fabienne; Jansen, Martin

    2012-01-01

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

  10. Radium and barium in the Amazon River system

    International Nuclear Information System (INIS)

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

  11. A comparison study between diagnostic value of sonography and Barium swallow in gasteroesophageal reflux in pediatrics

    Directory of Open Access Journals (Sweden)

    Fallahi G

    2001-10-01

    Full Text Available One of the common problems in children and specially in infants is gasteroesophageal reflux (G.E.R. Present study was performed to compare diagnostic value of lower esophageal sonography with barium swallow. This study was conducted on 50 patients 1 month to 15 years age in center of pediatric clinic of Tehran, during the years 1999-2000. Patients suspected to have G.E.R studied with lower esophageal sonography and barium swallow and at the end, their results were compared with esophageal PH monitoring as a standard test. In this study sensevity of sonography was 90 percent against 50 percent for barium swallow but specifity of two test was the same 35 percent. We can concluded that sonography is a non invasive, low cost, with less side effects than barium swallow. We recommend sonography in place of barium swallow in diagnosis of G.E.R.

  12. A Comparison between the Diagnostic Value of Sonography vs. Barium Swallow In Gastroesdophageal Reflux in Children

    Directory of Open Access Journals (Sweden)

    F. Zandie

    2003-06-01

    Full Text Available Background: One of the common problems in children, especially infants, is gastroesophageal reflux (GER. Objectives:This study was performed to compare the diagnostic value of lower esophageal sonography with that of barium swallow. Patients and method: Our trial was a triple-blind, performed on 50 patients of 1 month to 15 years of age. The patients suspicious of having GER were evaluated by sonography and barium swallow. Esophageal pH monitoring was the standard test, and both the ultrasound and barium swallow were compared to it. Results: The results showed that sonography was 90% sensitive, vs. 50% for barium swallow. Both tests had the same specificity equal to 35%. Conclusion: We concluded that sonography was a better test than barium swallows, for evaluation of suspected patients with GER, and screening of the infants.

  13. Effect of promoters including WO3 and BaO on the activity and durability of V2O5/sulfated TiO2 catalyst for NO reduction by NH3

    International Nuclear Information System (INIS)

    The effect of tungsten and barium oxides on the activity and durability of V2O5/TiO2 catalyst for NO reduction by NH3 was examined. Tungsten enhanced the NO removal activity of V2O5 catalyst supported on sulfur-free TiO2, while no effect of tungsten was observed for the V2O5 catalyst supported on sulfated TiO2. The tungsten oxide promotes the formation of polymeric vanadate that is a strong active reaction site for NO reduction by NH3. When both tungsten and sulfur simultaneously exist on the surface of V2O5/TiO2, the sulfur species seems to play a more important role for NO removal activity than tungsten. The tungsten oxide on the V2O5/TiO2 catalyst also enhances the activity for SO2 oxidation by promoting the adsorption of SO2, regardless of the presence of sulfur species on the catalyst surface. The NO removal activity of V2O5 catalyst supported on sulfur-free TiO2 has been significantly reduced by barium oxide, mainly due to the formation of inactive V-O-Ba compound through the strong interaction of vanadia with barium oxide. No change of NO removal activity over V2O5-BaO/sulfated TiO2, however, was examined by the addition of barium oxide, since the structure of vanadium oxide was not altered on the surface of the sulfated TiO2. The SO2 oxidation reaction over V2O5-BaO/TiO2 catalysts was significantly suppressed by the addition of barium oxide to the catalyst. The barium oxide seems to reduce the redox ability of vanadium oxide on the catalyst surface as well as the adsorption capacity of SO2. Based on the temperature programmed reduction (TPR), Raman and XPS observations, the surface structure of vanadium and its interaction with tungsten and barium oxides has been illustrated when sulfur exists on the surface of TiO2

  14. Anion and cation diffusion in barium titanate and strontium titanate; Anionen- und Kationendiffusion in Barium- und Strontiumtitanat

    Energy Technology Data Exchange (ETDEWEB)

    Kessel, Markus Franz

    2012-12-19

    Perovskite oxides show various interesting properties providing several technical applications. In many cases the defect chemistry is the key to understand and influence the material's properties. In this work the defect chemistry of barium titanate and strontium titanate is analysed by anion and cation diffusion experiments and subsequent time-of-flight secondary ion mass spectrometry (ToF-SIMS). The reoxidation equation for barium titanate used in multi-layer ceramic capacitors (MLCCs) is found out by a combination of different isotope exchange experiments and the analysis of the resulting tracer diffusion profiles. It is shown that the incorporation of oxygen from water vapour is faster by orders of magnitude than from molecular oxygen. Chemical analysis shows the samples contain various dopants leading to a complex defect chemistry. Dysprosium is the most important dopant, acting partially as a donor and partially as an acceptor in this effectively acceptor-doped material. TEM and EELS analysis show the inhomogeneous distribution of Dy in a core-shell microstructure. The oxygen partial pressure and temperature dependence of the oxygen tracer diffusion coefficients is analysed and explained by the complex defect chemistry of Dy-doped barium titanate. Additional fast diffusion profiles are attributed to fast diffusion along grain boundaries. In addition to the barium titanate ceramics from an important technical application, oxygen diffusion in cubic, nominally undoped BaTiO{sub 3} single crystals has been studied by means of {sup 18}O{sub 2}/{sup 16}O{sub 2} isotope exchange annealing and subsequent determination of the isotope profiles in the solid by ToF-SIMS. It is shown that a correct description of the diffusion profiles requires the analysis of the diffusion through the surface space-charge into the material's bulk. Surface exchange coefficients, space-charge potentials and bulk diffusion coefficients are analysed as a function of oxygen partial

  15. Structural and magnetic properties of Vanadium Doped M- Type Barium Hexaferrite (BaFe12-xVxO19)

    Science.gov (United States)

    Awadallah, Ahmad; Mahmood, Sami H.; Maswadeh, Yazan; Bsoul, Ibrahim; Aloqaily, Aynour

    2015-10-01

    Precursor powders of barium hexaferrite doped with vanadium, BaFe12-xVxO19 with (x = 0.1, 0.2, 0.3, 0.4, 0.5), were prepared using the ball milling technique and then sintered at different temperatures for 2 h. The structural properties of the prepared samples were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM), while the magnetic properties were examined by the vibrating sample magnetometry (VSM). XRD and SEM studies of the samples sintered at 1100° C indicated the presence of Ba3V2O8 and α-Fe2O3 non-magnetic oxide phases in addition to BaM hexaferrite phase. The fractions of the nonmagnetic oxide phases were found to increase with increasing x, and sintering the samples at temperatures higher than 1100° C was found to reduce the amounts of these non-magnetic phases only slightly. However, the addition of barium in excess of the stoichiometric ratio was found to remove the α-Fe2O3 oxide, and improve the saturation magnetization of the samples significantly. In addition, washing these samples with HCl was found to improve the saturation magnetization further. The effect of sintering the samples at higher temperatures was also found to reduce the coercivity due to growth of the particle size. However, the coercivity of all samples remained high enough for potential permanent magnet and magnetic recording applications.

  16. Synthesis of Barium Hexaferrite/iron Oxides Magnetic Nano-Composites via High Energy Ball Milling and Subsequent Heat Treatment

    Science.gov (United States)

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

    Barium hexaferrite (BaFe12O19) is a hard magnetic ceramic with superior magnetic properties and in powder form has potential for application in high density recording media. In this research a mechano-chemical approach was applied in order to achieve a nano-structured magnetic composite. Graphite was used to reduce barium hexaferrite in mechanical milling medium under argon atmosphere. Milling was carried out with a ball to powder mass ratio of 35 and rotation speed of 300 rpm. Effects of milling time on phase composition and morphology of the samples were evaluated by XRD and SEM techniques, respectively. XRD results revealed that after 20 hours of milling, nano-composite of BaFe12O19/Fe3O4/Fe2O3 was obtained. By extending the milling time to 40 hours, FeO was detected as the dominant crystalline phase with crystallite size of 22 nm. Composite of Fe/FeO/Fe3O4 was synthesized by controlled heat treatment of the 40 hours milled sample. SEM results revealed that particle size in the aforementioned heat treated composite sample reached to about 89 nm and the morphology of the samples changed slightly.

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

    Science.gov (United States)

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

    2008-01-01

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

  18. Production of potassium manganate and barium manganate from spent zinc-MnO2 dry cells via fusion with potassium hydroxide

    Science.gov (United States)

    da Rocha, Renan Azevedo; Quintanilha, Carolina Leão; Lanxin, Thayná Viana; Afonso, Júlio Carlos; Vianna, Cláudio Augusto; Gante, Valdir; Mantovano, José Luiz

    2014-12-01

    This work describes a route for extracting manganese and zinc from spent zinc-manganese dioxide dry cells via fusion of the electroactive components with potassium hydroxide to form potassium manganate (K2MnO4) and soluble zincates. The fused mass was dissolved in aqueous KOH and the insoluble matter was separated. Under the best optimal conditions, 70-78 wt% of manganese was solubilized as K2MnO4 whereas 30-44 wt% of zinc was solubilized as [Zn(OH)4]2- ions. Lead was the only minor component dissolved in detectable amounts. Manganese was isolated by a one-step precipitation procedure as barium manganate (BaMnO4) or via crystallization of K2MnO4. Lead and excess barium were isolated as sulfate by adding K2SO4. Zinc was precipitated as hydroxide after neutralizing the alkaline solution with H2SO4. pH control is essential to avoid decomposition of manganate ions and for the sequential precipitation of leached elements. K2SO4 was partially recovered as by-product after partial evaporation of the neutralized solution.

  19. New Technique for Barium Daughter Ion Identification in a Liquid Xe-136 Double Beta Decay Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Fairbank, William [Colorado State Univ., Fort Collins, CO (United States)

    2016-06-08

    This work addresses long-standing issues of fundamental interest in elementary particle physics. The most important outcome of this work is a new limit on neutrinoless double beta decay. This is an extremely rare and long sought after type of radioactive decay. If discovered, it would require changes in the standard model of the elementary constituents of matter, and would prove that neutrinos and antineutrinos are the same, a revolutionary concept in particle physics. Neutrinos are major components of the matter in the universe that are so small and so weakly interacting with other matter that their masses have not yet been discovered. A discovery of neutrinoless double beta decay could help determine the neutrino masses. An important outcome of the work on this project was the Colorado State University role in operating the EXO-200 neutrinoless double beta decay experiment and in analysis of the data from this experiment. One type of double beta decay of the isotope 136Xe, the two-neutrino variety, was discovered in this work. Although the other type of double beta decay, the neutrinoless variety, was not yet discovered in this work, a world’s best sensitivity of 1.9x1025 year half-life was obtained. This result rules out a previous claim of a positive result in a different isotope. This work also establishes that the masses of the neutrinos, are less than one millionth of that of electrons. A unique EXO-200 analysis, in which the CSU group had a leading role, has established for the first time ever in a liquid noble gas the fraction of daughter atoms from alpha and beta decay that are ionized. This result has important impact on other pending studies, including nucleon decay and barium tagging. Novel additional discoveries include multiphoton ionization of liquid xenon with UV pulsed lasers, which may find application in calibration of future noble liquid detectors, and studies of association and dissociation reactions of Ba+ ions in gaseous xenon. Through

  20. 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.

    Science.gov (United States)

    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

  1. Ruthenium and hafnium abundances in giant and dwarf barium stars

    CERN Document Server

    Allen, D M

    2007-01-01

    We present abundances for Ru and Hf, compare them to abundances of other heavy elements, and discuss the problems found in determining Ru and Hf abundances with laboratory gf-values in the spectra of barium stars. We determined Ru and Hf abundances in a sample of giant and dwarf barium stars, by the spectral synthesis of two RuI (4080.574A and 4757.856A) and two HfII (4080.437A and 4093.155A) transitions. The stellar spectra were observed with FEROS/ESO, and the stellar atmospheric parameters lie in the range 4300 < Teff/K < 6500, -1.2 < [Fe/H] <= 0 and 1.4 <= log g < 4.6. The HfII 4080A and the RuI 4758A observed transitions result in a unreasonably high solar abundance, given certain known uncertainties, when fitted with laboratory gf-values. For these two transitions we determined empirical gf-values by fitting the observed line profiles of the spectra of the Sun and Arcturus. For the sample stars, this procedure resulted in a good agreement of Ru and Hf abundances given by the two availa...

  2. Materials Synthesis Of Barium Hexa ferrite Used Local Natural Resources

    International Nuclear Information System (INIS)

    The magnetic materials of barium hexa ferrites, Ba O.6Fe2O3 successfully synthesized by powder metallurgy method used local natural resources from materials waste of steel fabrication (HSM, CRM), waste of polymer fabrication (LK) as well as iron sands (PBA). These waste as well as iron sands were the main resources of iron oxide, Fe2O3. The barium oxide used in this experiments are from BaCO3 product of Merck, and BaCO4 which is commercially available in the market as barite. Phase identification by x-ray diffraction technique show the synthesized magnetic materials are agreed with the available commercial product, (SUMI). The energy product maximum (BH)max measured by vibrating sample magnetometer (VSM) for the samples used HSM-, CRM- and BaCO3 as basic materials are 1.141 MGOe and 1.136 MGOe while SUMI is 1.142 MGOe. However for the samples made from LK-, PBA- used of BaCO3 or CRM- with barite, the energy product maximum (BH)max are relatively lower than commercial product

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

    International Nuclear Information System (INIS)

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

  4. Thermal expansion behaviour of barium and strontium zirconium phosphates

    Indian Academy of Sciences (India)

    P Srikari Tantri; K Geetha; A M Umarji; Sheela K Ramasesha

    2000-12-01

    Ba1.5–SrZr4P5SiO24 compounds with = 0, 0.25, 0.5, 0.75, 1.0, 1.25 and 1.5, belonging to the low thermal expansion NZP family were synthesized by the solid state reaction method. The XRD pattern could be completely indexed with respect to R$\\bar{3}$ space group indicating the ordering of vacancy at the divalent cation octahedral sites. The microstructure and bulk thermal expansion coefficient from room temperature to 800°C of the sintered samples have been studied. All the samples show very low coefficient of thermal expansion (CTE), with = 0 samples showing negative expansion. A small substitution of strontium in the pure barium compound changes the sign of CTE. Similarly, = 1.5 sample (pure strontium) shows a positive CTE and a small substitution of barium changes its sign. = 1.0 and 1.25 samples have almost constant CTE over the entire temperature range. The low thermal expansion of these samples can be attributed to the ordering of the ions in the crystal structure of these materials.

  5. Redox processes in highly yttrium-doped barium titanate

    International Nuclear Information System (INIS)

    The changes of microstructure occurring during oxidation of the reduced form of yttrium-doped barium titanate (Ba1-xYx?Ti1-x4+Tix3+O3) have been studied. Samples were sintered under reduction conditions at PO2=10-4Pa and oxidized by annealing at high temperatures (1150 and 1350 deg. C) in air. Depending on yttrium concentration, the oxidation of the reduced form of the yttrium-doped BaTiO3 caused precipitation of the phase Ba6Ti17O40 or the phases Ba6Ti17O40 and Y2Ti2O7. The precipitates had well-defined orientational relationships with the perovskite matrix. Oxidation of the reduced form of doped barium titanate results in formation of the phase Ba1-xYx?Ti1-x/44+(VTi-bar )x/4O3 responsible for increase in the resistance of outer grain layers, which lie between grain boundaries and grain

  6. The Kerr nonlinearity of the beta-barium borate crystal

    DEFF Research Database (Denmark)

    Bache, Morten; Guo, Hairun; Zhou, Binbin;

    2013-01-01

    A popular crystal for ultrafast cascading experiments is beta-barium-borate (β-BaB2O4, BBO). It has a decent quadratic nonlinear coefficient, and because the crystal is anisotropie it can be birefringence phase-matched for type I (oo → e) second-harmonic generation (SHG). For femtosecond experime......A popular crystal for ultrafast cascading experiments is beta-barium-borate (β-BaB2O4, BBO). It has a decent quadratic nonlinear coefficient, and because the crystal is anisotropie it can be birefringence phase-matched for type I (oo → e) second-harmonic generation (SHG). For femtosecond...... experiments BBO is popular because of low dispersion and a high damage threshold. The main attractive property of ultrafast cascading is that the induced cascading nonlinearity nI 2, casc can be negative, i.e. generate a self-defocusing Kerr-like nonlinearity. However, the material Kerr nonlinearity nI 2......, Kerr is self-focusing and competes with the cascading nonlinearity. Therefore, precise knowledge of its strength is crucial. We perform an experiment measuring the main c ü tensor component, and together with literature experimental data [1], we propose a cu value composed of 14 different data points...

  7. Sulfates on Mars: Indicators of Aqueous Processes

    Science.gov (United States)

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

    2006-01-01

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

  8. Liquid-Phase Processing of Barium Titanate Thin Films

    Science.gov (United States)

    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

  9. Highly Selective Liquid Membrane Sensor Based on 1,3,5-Triphenylpyrylium Perchlorate for Quick Monitoring of Sulfate Ions

    Energy Technology Data Exchange (ETDEWEB)

    Ganjali, Mohammad Reza; Ghorbani, Maryam; Daftari, Azadeh; Norouzi, Parviz; Pirelahi, Hooshang; Dargahani, Hossein Daryanavard [Tehran University, Tehran (Iran, Islamic Republic of)

    2004-02-15

    A highly selective membrane electrode based on 1,3,5-triphenylpyrylium perchlorate (TPPP) is presented. The proposed electrode shows very good selectivity for sulfate ions over a wide variety of common inorganic and organic anions. The sensor displays a nice Nernstian slope of -29.7 mV per decade. The working concentration ranges of the electrode is 1.0 x 10{sup -1} . 6.3 x 10{sup -6} M with a detection limit of 4.0 x 10{sup -6} M (480 ng per mL). The response time of the sensor in whole concentration ranges is very short (< 6 s). The response of the sensor is independent on the pH range of 2.5-9.5. The best performance was obtained with a membrane composition of 32% PVC, 59% benzyl acetate, 5% TPPP and 4% hexadecyltrimethylammonium bromide. It was successfully used as an indicator electrode for titration of sulfate ions with barium ions. The electrode was also applied for determination of salbutamol sulfate and paramomycine sulfate

  10. Highly Selective Liquid Membrane Sensor Based on 1,3,5-Triphenylpyrylium Perchlorate for Quick Monitoring of Sulfate Ions

    International Nuclear Information System (INIS)

    A highly selective membrane electrode based on 1,3,5-triphenylpyrylium perchlorate (TPPP) is presented. The proposed electrode shows very good selectivity for sulfate ions over a wide variety of common inorganic and organic anions. The sensor displays a nice Nernstian slope of -29.7 mV per decade. The working concentration ranges of the electrode is 1.0 x 10-1 . 6.3 x 10-6 M with a detection limit of 4.0 x 10-6 M (480 ng per mL). The response time of the sensor in whole concentration ranges is very short (< 6 s). The response of the sensor is independent on the pH range of 2.5-9.5. The best performance was obtained with a membrane composition of 32% PVC, 59% benzyl acetate, 5% TPPP and 4% hexadecyltrimethylammonium bromide. It was successfully used as an indicator electrode for titration of sulfate ions with barium ions. The electrode was also applied for determination of salbutamol sulfate and paramomycine sulfate

  11. The influence of temperature on limestone sulfation and attrition under fluidized bed combustion conditions

    Energy Technology Data Exchange (ETDEWEB)

    Montagnaro, Fabio [Dipartimento di Chimica - Universita degli Studi di Napoli Federico II, Complesso Universitario del Monte di Sant' Angelo, 80126 Napoli (Italy); Salatino, Piero [Istituto di Ricerche sulla Combustione - CNR, Piazzale Vincenzo Tecchio 80, 80125 Napoli (Italy); Dipartimento di Ingegneria Chimica - Universita degli Studi di Napoli Federico II, Piazzale Vincenzo Tecchio 80, 80125 Napoli (Italy); Scala, Fabrizio [Istituto di Ricerche sulla Combustione - CNR, Piazzale Vincenzo Tecchio 80, 80125 Napoli (Italy)

    2010-04-15

    The influence of temperature on attrition of two limestones during desulfurization in a fluidized bed reactor was investigated. Differences in the microstructure of the two limestones were reflected by a different thickness of the sulfate shell formed upon sulfation and by a different value of the ultimate calcium conversion degree. Particle attrition and fragmentation were fairly small under moderately bubbling fluidization conditions for both limestones. An increase of temperature from 850 C to 900 C led to an increase of the attrition rate, most likely because of a particle weakening effect caused by a faster CO{sub 2} evolution during calcination. This weakening effect, however, was not sufficiently strong to enhance particle fragmentation in the bed. The progress of sulfation, associated to the build-up of a hard sulfate shell around the particles, led in any case to a decrease of the extent of attrition. Sulfation at 900 C was less effective than at 850 C, and this was shown to be related to the porosimetric features of the different samples. (author)

  12. Heparin cofactor II is degraded by heparan sulfate and dextran sulfate.

    Science.gov (United States)

    Saito, Akio

    2015-02-20

    Heparan sulfate normally binds to heparin cofactor II and modulates the coagulation pathway by inhibiting thrombin. However, when human heparin cofactor II was incubated with heparan sulfate, heparin cofactor II became degraded. Other glycosaminoglycans were tested, including hyaluronic acid, chondroitin sulfates, dermatan sulfate, and heparin, but only dextran sulfate also degraded heparin cofactor II. Pretreatment of heparan sulfate with heparinase reduced its heparin cofactor II-degrading activity. Heparan sulfate and dextran sulfate diminished the thrombin inhibitory activity of heparin cofactor II. Other serpins, including antithrombin III and pigment epithelium-derived factor, were also degraded by heparan sulfate. This is the first evidence of acidic polysaccharides exhibiting protein-degrading activity without the aid of other proteins. PMID:25600805

  13. Modeling of ferric sulfate decomposition and sulfation of potassium chloride during grate‐firing of biomass

    DEFF Research Database (Denmark)

    Wu, Hao; Jespersen, Jacob Boll; Jappe Frandsen, Flemming;

    2013-01-01

    Ferric sulfate is used as an additive in biomass combustion to convert the released potassium chloride to the less harmful potassium sulfate. The decomposition of ferric sulfate is studied in a fast heating rate thermogravimetric analyzer and a volumetric reaction model is proposed to describe the...... process. The yields of sulfur oxides from ferric sulfate decomposition under boiler conditions are investigated experimentally, revealing a distribution of approximately 40% SO3 and 60% SO2. The ferric sulfate decomposition model is combined with a detailed kinetic model of gas‐phase KCl sulfation and a...... model of K2SO4 condensation to simulate the sulfation of KCl by ferric sulfate addition. The simulation results show good agreements with experiments conducted in a biomass grate‐firing reactor. The results indicate that the SO3 released from ferric sulfate decomposition is the main contributor to KCl...

  14. Preparation and properties of yttria doped tetragonal zirconia polycrystal/Sr-doped barium hexaferrite ceramic composites

    International Nuclear Information System (INIS)

    Highlights: • The 3Y-TZP/Sr-doped barium ferrite composites were prepared. • The saturation magnetization was improved by 15% with Sr-doping. • The dispersion coefficient p could reflect the microscopic lattice variation. • The composite with x = 0.5 had the maximum fracture toughness of 8.3 MPa m1/2. - Abstract: The effects of substitution of Ba2+ by Sr2+ on the magnetic property of barium ferrite and addition barium ferrite secondary phase to the 3 mol% yttria-doped tetragonal zirconia polycrystal (3Y-TZP) matrix on the mechanical property of composites were investigated. The Sr-doped barium ferrite (Ba1−xSrxFe12O19, x = 0, 0.25, 0.50 and 0.75) was synthesized by solid-state reaction in advance. Then 3Y-TZP/20 wt% Sr-doped barium ferrite composites were prepared by means of conventional ceramic method. It was found that a moderate amount of Sr added to barium ferrite could boost the saturation magnetization by 15% compared with the composites without Sr-doping. Besides, the composite with x = 0.50 possessed the best mechanical properties, such as 11.5 GPa for Vickers hardness and 8.3 MPa m1/2 for fracture toughness, respectively. It was demonstrated that magnetic and mechanical properties of the composites could be harmonized by the incorporation of barium ferrite secondary phase

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

    Science.gov (United States)

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

    2016-03-30

    A bio-based barium alginate film was prepared via a facile ionic exchange and casting approach. Its flammability, thermal degradation and pyrolysis behaviors, thermal degradation mechanism were studied systemically by limiting oxygen index (LOI), vertical burning (UL-94), microscale combustion calorimetry (MCC), thermogravimetric analysis (TGA) coupled with Fourier transform infrared analysis (FTIR) and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS). It showed that barium alginate film had much higher LOI value (52.0%) than that of sodium alginate film (24.5%). Moreover, barium alginate film passed the UL-94 V-0 rating, while the sodium alginate film showed no classification. Importantly, peak of heat release rate (PHRR) of barium alginate film in MCC test was much lower than that of sodium alginate film, suggested that introduction of barium ion into alginate film significantly decreased release of combustible gases. TG-FTIR and Py-GC-MS results indicated that barium alginate produced much less flammable products than that of sodium alginate in whole thermal degradation procedure. Finally, a possible degradation mechanism of barium alginate had been proposed. PMID:26794953

  16. Particle measurement and brine chemistry at the Salton Sea Deep Well

    Energy Technology Data Exchange (ETDEWEB)

    Robertus, R.J.; Kindle, C.H.; Sullivan, R.G.; Shannon, D.W.

    1991-09-01

    The Advanced Brine Chemistry Project, a part of the US Department of Energy's Geothermal Energy Program, is addressing operating problems associated with scaling and corrosion at geothermal power plants. Under this project, Pacific Northwest Laboratory conducted a series of tests at the Salton Sea Deep Well, which has one of the highest solids contents in the world. The purpose of the tests was to evaluate monitoring instrumentation under field conditions and relate particulate formation to the brine chemistry. The instrumentation, was evaluated under scaling geothermal conditions using two different principles: ultrasonic reflection and laser light scattering. The following conclusions were drawn from the instrumentation testing and brine chemistry and particulate analyses. (1) Using reflected ultrasonic impulses to detect suspended particles has been demonstrate for on-line application in a geothermal brine with strong scaling tendencies. Advantages over laser light scattering include improved high-temperature durability for the transducer and longer operation with less maintenance. (2) Counting and sizing particles using laser light scattering requires constant maintenance in geothermal applications. (3) Silica is the dominant scale species and appears in amounts orders of magnitude greater than other minor species such as barium sulfate. (4) The silica that formed at high temperatures and short residence times is very gelatinous and difficult to filter out of the brine. (5) Correlation of instrument readings with particle collection data was difficult because conditions on the filter (i.e., temperature, flowrate, and pressure) could not be maintained constant for long enough intervals to obtain comparable information. 5 refs., 27 figs., 2 tabs.

  17. Why Is the Climate Forcing of Sulfate Aerosols So Uncertain?

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Sulfate aerosol particles have strong scattering effect on the solar radiation transfer which results in increasing the planet albedo and, hence, tend to cool the earth-atmosphere system. Also, aerosols can act as the cloud condensation nuclei (CCN) which tend to increase the albedo of clouds and cool the global warming. The ARPEGE-Climat version 3 AGCM with FMR radiation scheme is used to estimate the direct and indirect radiative forcing of sulfate aerosols. For minimizing the uncertainties in assessing this kind of cooling effect, all kinds of factors are analyzed which have been mixed in the assessment process and may lead to the different results of the radiative forcing of aerosols. It is noticed that one of the uncertainties to assess the climate forcing of aerosols by GCM results from the different definition of radiative forcing that was used. In order to clarify this vague idea, the off-line case for considering no feedbacks and on-line case for including all the feedbacks have been used for assessment. The direct forcing of sulfate aerosols in off-line case is -0.57 W/m2 and -0.38 W/m2 for the clear sky and all sky respectively. The value of on-line case appears to be a little larger than that in off-line case chiefly due to the feedback of clouds. The indirect forcing of sulfate aerosols in off-line case is -1.4 W / m2 and -1.0 W / m2 in on-line case. The radiative forcing of sulfate aerosols has obvious regional characteristics. There is a larger negative radiative forcing over North America, Europe and East Asia. If the direct and indirect forcing are added together, it is enough to offset the positive radiative forcing induced by the greenhouse gases in these regions.

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

    International Nuclear Information System (INIS)

    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. - Highlights: • The Co was first time substituted by Mn–Ni in ferrites. • The substituted ferrites had good microwave absorption. • The doped ferrites had broad bandwidth and low reflection loss

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

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Pingyuan; Xiong, Kun [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010 (China); Ju, Kui [Guizhou Institute of Metallurgy and Chemical Engineering, Guiyang 550002 (China); Li, Shengnan [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010 (China); Xu, Guangliang, E-mail: xuguangliang@swust.edu.cn [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010 (China)

    2015-07-01

    To achieve stronger microwave attenuation and larger bandwidth in electromagnetic absorber, the nickel ions (Ni{sup 2+}) and manganese ions (Mn{sup 2+}) were employed to partially replace the cobalt ions (Co{sup 2+}) in BaCoTiFe{sub 10}O{sub 19}, and the doped barium hexaferrite (Ba(MnNi){sub 0.2}Co{sub 0.6}TiFe{sub 10}O{sub 19} and Ba(MnNi){sub 0.25}Co{sub 0.5}TiFe{sub 10}O{sub 19}) 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){sub 0.2}Co{sub 0.6}TiFe{sub 10}O{sub 19}) 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){sub 0.25}Co{sub 0.5}TiFe{sub 10}O{sub 19} 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){sub 0.2}Co{sub 0.6}TiFe{sub 10}O{sub 19} and Ba(MnNi){sub 0.25}Co{sub 0.5}TiFe{sub 10}O{sub 19} could be the good microwave absorbers, which have great potentials to be applied in the high frequency fields of the microwave absorbing materials. - Highlights: • The Co was first time substituted by Mn–Ni in ferrites. • The substituted ferrites had good microwave absorption. • The doped ferrites had broad bandwidth and low reflection loss.

  20. Study of the dielectric properties of barium titanate-polymer composites

    Energy Technology Data Exchange (ETDEWEB)

    Pant, H.C. [R and D Laboratory, Defence Laboratory, Camouflage Division, Defence Laboratory Ratanada Palace, Jodhpur 342011, Rajasthan (India); Patra, M.K. [R and D Laboratory, Defence Laboratory, Camouflage Division, Defence Laboratory Ratanada Palace, Jodhpur 342011, Rajasthan (India); Verma, Aditya [R and D Laboratory, Defence Laboratory, Camouflage Division, Defence Laboratory Ratanada Palace, Jodhpur 342011, Rajasthan (India); Vadera, S.R. [R and D Laboratory, Defence Laboratory, Camouflage Division, Defence Laboratory Ratanada Palace, Jodhpur 342011, Rajasthan (India); Kumar, N. [R and D Laboratory, Defence Laboratory, Camouflage Division, Defence Laboratory Ratanada Palace, Jodhpur 342011, Rajasthan (India)]. E-mail: nkjainjd@yahoo.com

    2006-07-15

    A comparative study of complex dielectric properties has been carried out at the X-band of microwave frequencies of composites of barium titanate (BaTiO{sub 3}) with two different polymer matrices: insulating polyaniline (PANI) powder (emeraldine base) and maleic resin. From these studies, it is observed that the composites of BaTiO{sub 3} with maleic resin show normal composite behavior and the dielectric constant follows the asymmetric Bruggeman model. In contrast, the composites of BaTiO{sub 3} with PANI show an unusual behavior wherein even at a low concentration of PANI (5 wt.%) there is a drastic reduction in the dielectric constant of BaTiO{sub 3}. This behavior of the dielectric constant is explained on the basis of coating of BaTiO{sub 3} particles by PANI which in turn is attributed to the highly surface adsorbing character. The materials have also been characterized using Fourier transform infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy and optical microscopy studies.

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

    International Nuclear Information System (INIS)

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

  2. Comparison of normal and asthmatic subjects' responses to sulfate pollutant aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Utell, M.J.; Morrow, P.E.; Hyde, R.W.

    1980-01-01

    Epidemiological studies support an association between elevated levels of sulfates and acute respiratory disease. To determine if these pollutants produce airway hyperreactivity, 16 normal and 17 asthmatic subjects inhaled a control NaCl aerosol and the following sulfates: ammonium sulfate, sodium bisulfate, ammonium bisulfate, and sulfuric acid. A Lovelace generator produced particles with an average MMAD of approx. 1.0 ..mu..m (sigma/sub g/ approx. = 2.0) and concentrations of 0.1 and 1.0 mg/m/sup 3/. By double-blind randomization, all subjects breathed these aerosols for a 16-minute period. To determine if sulfate inhalation caused increased reactivity to a known bronchoconstrictor, all subjects inhaled carbachol following each 16-minute exposure. Before, during, and after exposure, pulmonary function studies were performed. When compared to NaCl, sulfate (1 mg/m/sup 3/) produced significant reductions in airway conductance and flow rates in asthmatics. The two most sensitive asthmatics demonstrated changes even at 0.1 mg/m/sup 3/ sulfate. To a far more significant degree, the bronchoconstrictor action of carbachol was potentiated by sulfates more or less in relation to their acidity in normals and asthmatics.

  3. Synthesis and Characterization of Barium-Vanadium Oxide Nanocomposite Using a Facile thermolysis Approach

    OpenAIRE

    Niloufar Akbarzadeh-T; Leila Amiri-O

    2015-01-01

    In this investigation, we report synthesis of new cationic-anionic Barium-Vanadium complex with 2, 6- pyridinedicarboxylic acid ligand. This compound [Ba(H2O)8][VO2(dipic)]2(1) has been characterized using elemental analyses, FT-IR, UV–Vis and Cyclic voltammetry (CV) techniques. Also in this study we report facile synthesis of Barium-Vanadium Oxide nanoparticle under thermal decomposition, using precursor complex (1). Characterization of Barium-Vanadium Oxide nanocomposites was carried out by...

  4. Microscopic insight into nuclear structure properties of proton-rich barium isotopes

    International Nuclear Information System (INIS)

    Variation after projection (VAP) calculations with Hartree-Bogoliubov (HB) Ansatz have been carried out for A=120-136 barium isotopes. In this framework, the yrast spectra with Jmaxπ=10+, B(E2) transition probabilities, quadrupole (β2) and hexadecapole (β4) deformation parameters for even-even barium isotopes have been obtained. The results of the calculation give an indication that it is important to include the hexadecapole-hexadecapole component of the two-body interaction for obtaining various nuclear structure quantities in these barium isotopes. (author)

  5. Orbital elements of barium stars formed through a wind accretion scenario

    CERN Document Server

    Liu, J H; Liang, Y C; Peng, Q H

    2000-01-01

    Taking the total angular momentum conservation in place of the tangential momentum conservation, and considering the square and higher power terms of orbital eccentricity e, the changes of orbital elements of binaries are calculated for wind accretion scenario. These new equations are used to quantitatively explain the observed (e,logP) properties of normal G, K giants and barium stars. Our results reflect the evolution from G, K giant binaries to barium binaries, moreover, the barium stars with longer orbital periods P>1600 days may be formed by accreting part of the ejecta from the intrinsic AGB stars through wind accretion scenario.

  6. Application of barium fluoride for sulfur selective extraction at X-ray spectroscopic analysis of steel

    International Nuclear Information System (INIS)

    In order to increase the sensitivity of X-ray spectroscopic identification of sulphur in steels the application of barium fluoride for selective extraction of sulphate ions was proposed by authors of present work. The influence of concentration of sulphate ions, iron, nickel, chromium and titanium cations as well as acidity of solutions on the coefficient of distribution of sulphate ions in the system barium fluoride-water was studied. The distribution coefficients were calculated, the completeness of extraction was calculated as well. It is defined that sulphate ions from solutions containing cations of heavy metals and other anions can be extracted by means of barium fluoride.

  7. Spectrophotometric determination of L-cysteine by using polyvinylpyrrolidone-stabilized silver nanoparticles in the presence of barium ions

    Science.gov (United States)

    Bamdad, Farzad; Khorram, Fateme; Samet, Maryam; Bamdad, Kourosh; Sangi, Mohammad Reza; Allahbakhshi, Fateme

    2016-05-01

    In this article a simple and selective colorimetric probe for cysteine determination using silver nano particles (AgNPS) is described. The determination process was based upon the surface plasmon resonance properties of polyvinylpyrrolidone-stabilized AgNPS. Interaction of AgNPS with cysteine molecules in the presence of barium ions induced a red shift in the surface plasmon resonance (SPR) maximum of AgNPs, as a result of nanoparticle aggregation. Consequently, yellow color of AgNP solution was changed to pink. The linear range for the determination of cysteine was 3.2-8.2 μM (R = 0.9965) with a limit of detection equal to 2.8 μM (3σ). The proposed method was successfully applied to the determination of cysteine in human plasma samples. Acceptable recovery results of the spiked samples confirmed the validity of the proposed method.

  8. Concentrations of lead, cadmium and barium in urban garden-grown vegetables: the impact of soil variables.

    Science.gov (United States)

    McBride, Murray B; Shayler, Hannah A; Spliethoff, Henry M; Mitchell, Rebecca G; Marquez-Bravo, Lydia G; Ferenz, Gretchen S; Russell-Anelli, Jonathan M; Casey, Linda; Bachman, Sharon

    2014-11-01

    Paired vegetable/soil samples from New York City and Buffalo, NY, gardens were analyzed for lead (Pb), cadmium (Cd) and barium (Ba). Vegetable aluminum (Al) was measured to assess soil adherence. Soil and vegetable metal concentrations did not correlate; vegetable concentrations varied by crop type. Pb was below health-based guidance values (EU standards) in virtually all fruits. 47% of root crops and 9% of leafy greens exceeded guidance values; over half the vegetables exceeded the 95th percentile of market-basket concentrations for Pb. Vegetable Pb correlated with Al; soil particle adherence/incorporation was more important than Pb uptake via roots. Cd was similar to market-basket concentrations and below guidance values in nearly all samples. Vegetable Ba was much higher than Pb or Cd, although soil Ba was lower than soil Pb. The poor relationship between vegetable and soil metal concentrations is attributable to particulate contamination of vegetables and soil characteristics that influence phytoavailability. PMID:25163429

  9. Influence of acid catalysts on the structural and magnetic properties of nanocrystalline barium ferrite prepared by sol-gel method

    International Nuclear Information System (INIS)

    BaFe12O19 powders with nanocrystalline size were prepared by sol-gel techniques. Nitric, hydrochloric, acetic and stearic acid were used to improve the magnetic properties. Amorphous gels were formed with Fe/Ba molar ratio of 10.5. Then powders were obtained by subsequent heat treatment at 800-1000 deg. C for 1 h. Barium ferrite powder was also synthesized by solid state reaction at 1210 deg. C. X-ray diffraction, scanning electron microscopy and transmission electron microscopy (TEM) experiments were conducted to evaluate structural properties of the samples. The value of the effective magnetic susceptibility was measured. The results show that the magnetoplumbite structure was formed in all of the powders. The TEM observation showed that the minimum particle size (20 nm) was produced with the stearic acid catalyst. The highest value of the effective magnetic susceptibility was achieved also using stearic acid

  10. Hygroscopicity of organic compounds from biomass burning and their influence on the water uptake of mixed organic ammonium sulfate aerosols

    Science.gov (United States)

    Lei, T.; Zuend, A.; Wang, W. G.; Zhang, Y. H.; Ge, M. F.

    2014-10-01

    Hygroscopic behavior of organic compounds, including levoglucosan, 4-hydroxybenzoic acid, and humic acid, as well as their effects on the hygroscopic properties of ammonium sulfate (AS) in internally mixed particles are studied by a hygroscopicity tandem differential mobility analyzer (HTDMA). The organic compounds used represent pyrolysis products of wood that are emitted from biomass burning sources. It is found that humic acid aerosol particles only slightly take up water, starting at RH (relative humidity) above ~70%. This is contrasted by the continuous water absorption of levoglucosan aerosol particles in the range 5-90% RH. However, no hygroscopic growth is observed for 4-hydroxybenzoic acid aerosol particles. Predicted water uptake using the ideal solution theory, the AIOMFAC model and the E-AIM (with UNIFAC) model are consistent with measured hygroscopic growth factors of levoglucosan. However, the use of these models without consideration of crystalline organic phases is not appropriate to describe the hygroscopicity of organics that do not exhibit continuous water uptake, such as 4-hydroxybenzoic acid and humic acid. Mixed aerosol particles consisting of ammonium sulfate and levoglucosan, 4-hydroxybenzoic acid, or humic acid with different organic mass fractions, take up a reduced amount of water above 80% RH (above AS deliquescence) relative to pure ammonium sulfate aerosol particles of the same mass. Hygroscopic growth of mixtures of ammonium sulfate and levoglucosan with different organic mass fractions agree well with the predictions of the thermodynamic models. Use of the Zdanovskii-Stokes-Robinson (ZSR) relation and AIOMFAC model lead to good agreement with measured growth factors of mixtures of ammonium sulfate with 4-hydroxybenzoic acid assuming an insoluble organic phase. Deviations of model predictions from the HTDMA measurement are mainly due to the occurrence of a microscopical solid phase restructuring at increased humidity (morphology

  11. Evaluating Deterioration of Concrete by Sulfate Attack

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Effects of factors such as water to cement ratio, fly ash and silica fume on the resistance of concrete to sulfate attack were investigated by dry-wet cycles and immersion method. The index of the resistance to sulfate attack was used to evaluate the deterioration degree of concrete damaged by sulfate. The relationship between the resistance of concrete to sulfate attack and its permeability/porosity were analyzed as well as its responding mechanism. Results show that the depth of sulfate crystal attack from surface to inner of concrete can be reduced by decreasing w/c and addition of combining fly ash with silica fume. The variation of relative elastic modulus ratio and relative flexural strength ratio of various specimens before and after being subjected to sulfate attack was compared.

  12. Chondroitin Sulfate Perlecan Enhances Collagen Fibril Formation

    DEFF Research Database (Denmark)

    Kvist, A. J.; Johnson, A. E.; Mörgelin, M.;

    2006-01-01

    disaccharides typical for chondroitin sulfate E. Indeed, purified glycosaminoglycans from perlecan-enriched fractions of cartilage extracts contain elevated levels of 4,6-disulfated chondroitin sulfate disaccharides and enhance collagen fibril formation. The effect on collagen assembly is proportional to the...... content of the 4,6-disulfated disaccharide in the different cartilage extracts, with growth plate cartilage glycosaminoglycan being the most efficient enhancer. These findings demonstrate a role for perlecan chondroitin sulfate side chains in cartilage extracellular matrix assembly and provide an...... collagen type II fibril assembly by perlecan-null chondrocytes. Cartilage perlecan is a heparin sulfate or a mixed heparan sulfate/chondroitin sulfate proteoglycan. The latter form binds collagen and accelerates fibril formation in vitro, with more defined fibril morphology and increased fibril diameters...

  13. Infrared Spectroscopic Characterization of Calcium and Barium Hydrazone Complexes

    Directory of Open Access Journals (Sweden)

    *A. Adeniyi

    2013-06-01

    Full Text Available Hydrazones have attracted considerable interest on account of their biological activities. Introduction of calcium and barium metal ions into m- and p-nitrobenzoic hydrazones is expected to modify these biological properties for enhanced activity and versatility. The ligands were synthesized from the parent acids. The complexes have been characterized using C, H and N microanalyses and IR spectrometry. The IR spectral data of the ligands and complexes revealed bonding via the C=O and C=N groups. The suggested metal to ligand stoichiometries are: [M (m-NBHx]Cl2.yH2O, x, y = 1 and 4 for M = Ca; x, y = 2 and 3 for M = Ba respectively. [M(p-NBHx]Cl2.yH2O, x, y = 1 and 12 for M = Ca; x, y = 1 and 3 for M = Ba respectively. The structural deductions are tentative pending future X-ray structural studies.

  14. Conoscopic study of strontium-barium niobate single crystals

    International Nuclear Information System (INIS)

    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

  15. Pulsating aurora induced by upper atmospheric barium releases

    Science.gov (United States)

    Deehr, C.; Romick, G.

    1977-01-01

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

  16. Behaviour of barium and strontium oxides in liquid nitrogen tetroxide

    International Nuclear Information System (INIS)

    Chemical transformations of barium and strontium oxides (MeO, MeO2) in liquid nitrogen tetroxide are considered in the temperature range of 290-493 K. The data on IR and Raman spectra of the reaction products in the region of 2500-600 cm-1 are presented. No formation of nitrosonium complexes of the type NO[Me(NOsub(3))sub(n)]sub(m) and adducts of the type Me(NO3)2xmN2O4 is detected. It has been established that MeO2 possess a higher reactivity in liquid nitrogen tetroxide than MeO. Using the methods of vibrational spectroscopy the bands, characteristic of MeO2 are signled out in MeO samples being in contact with nitrogen tetroxide

  17. Stark effect in Rydberg states of helium and barium

    International Nuclear Information System (INIS)

    This thesis, which deals with the effect of an electric field up to moderate field strengths on atoms with two valence electrons outside closed shells, in casu helium and barium, contains chapter in which the linear Stark effect in the 1 snp 1,3p Rydberg states of helium (n around 40) has been studied in a CW laser-atomic beam experiment. The evolution of the angular momentum manifolds into the n-mixing regime was followed and avoided level crossings were observed. Stark manifolds were also calculated by diagonalization of the complete energy matrix in the presence of an electric field. It turned out to be necessary to include up to five n-values in the calculations already at moderate values of the field to reproduce the data within the experimental accuracy (a few MHz), especially in the regime of the avoided crossings. (author). 147 refs.; 30 figs.; 8 tabs

  18. Small polarons and point defects in barium cerate

    Science.gov (United States)

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

    2015-12-01

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

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

    Science.gov (United States)

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

    2016-07-25

    We investigate the potential of epitaxial calcium barium niobate (CBN) thin film grown by pulsed laser deposition for optical frequency conversion. Using second harmonic generation (SHG), we analyze the polarization response of the generated signal to determine the ratios d15 / d32 and d33 / d32 of the three independent components of the second-order nonlinear susceptibility tensor in CBN thin film. In addition, a detailed comparison to the signal intensity obtained in a y-cut quartz allows us to measure the absolute value of these components in CBN thin film: d15 = 5 ± 2 pm / V, d32 = 3.1 ± 0.6 pm / V and d33 = 9 ± 2 pm / V. PMID:27464195

  20. Barium titanate nanocomposite capacitor FY09 year end report.

    Energy Technology Data Exchange (ETDEWEB)

    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.

  1. Bronchography in dogs. Comparative study with two barium sulphate solutions

    International Nuclear Information System (INIS)

    Two solutions of barium sulphate, 60 and 30% w/v, were compared with the ''overflow'' Bronchographic method. Two groups of eight healthy adult does of both sexes, weighing 7 to 18 kg were used for the study. The dogs were anaesthetised with thiopentone sodium 2% (20 mg/kg iv). After intubation, each dog received contrast medium by a catheter connected to a syringe, in a 9 mi dose. Two series of two x-rays plates were taken in left lateral recumbent, 3 and 6 min after administering the contrast medium and in ventrodorsal projection, 30 sec. later. The x-ray plates obtained were analysed and compared intra and inter group considering the advance speed of the contrast medium, the radiographic density and outlines. Adverse reactions were controlled

  2. Barium depletion study on impregnated cathodes and lifetime prediction

    Science.gov (United States)

    Roquais, J. M.; Poret, F.; le Doze, R.; Ricaud, J. L.; Monterrin, A.; Steinbrunn, A.

    2003-06-01

    In the thermionic cathodes used in cathode ray-tubes (CRTs), barium is the key element for the electronic emission. In the case of the dispenser cathodes made of a porous tungsten pellet impregnated with Ba, Ca aluminates, the evaporation of Ba determines the cathode lifetime with respect to emission performance in the CRT. The Ba evaporation results in progressive depletion of the impregnating material inside the pellet. In the present work, the Ba depletion with time has been extensively characterized over a large range of cathode temperature. Calculations using the depletion data allowed modeling of the depletion as a function of key parameters. The link between measured depletion and emission in tubes has been established, from which an end-of-life criterion was deduced. Taking modeling into account, predicting accelerated life-tests were performed using high-density maximum emission current (MIK).

  3. Barium depletion study on impregnated cathodes and lifetime prediction

    International Nuclear Information System (INIS)

    In the thermionic cathodes used in cathode ray-tubes (CRTs), barium is the key element for the electronic emission. In the case of the dispenser cathodes made of a porous tungsten pellet impregnated with Ba, Ca aluminates, the evaporation of Ba determines the cathode lifetime with respect to emission performance in the CRT. The Ba evaporation results in progressive depletion of the impregnating material inside the pellet. In the present work, the Ba depletion with time has been extensively characterized over a large range of cathode temperature. Calculations using the depletion data allowed modeling of the depletion as a function of key parameters. The link between measured depletion and emission in tubes has been established, from which an end-of-life criterion was deduced. Taking modeling into account, predicting accelerated life-tests were performed using high-density maximum emission current (MIK)

  4. Gamma radiation induced darkening in barium gallo-germanate glass.

    Science.gov (United States)

    Chen, Xiaodong; Heng, Xiaobo; Tang, Guowu; Zhu, Tingting; Sun, Min; Shan, Xiujie; Wen, Xin; Guo, Jingyuan; Qian, Qi; Yang, Zhongmin

    2016-05-01

    Barium gallo-germanate (BGG) glass is an important glass matrix material used for mid-infrared transmission and mid-infrared fiber laser. In this study, we investigated the γ-ray irradiation induced darkening effect of BGG glass. Optical transmittance spectra, electron paramagnetic resonance (EPR) and thermoluminescence (TL) spectra were employed to investigate the γ-ray irradiation induced defects. Two kinds of Ge-related defects in the irradiated BGG glass, named Ge-related non-bridging oxygen hole center (Ge-NBOHC) and Ge-related electron centers (GEC), were verified. In addition, the absorption bands of the two defects have been separated and the peak absorptivity of Ge-NBOHC and GEC defects is at 375 nm and 315 nm, respectively. PMID:27137531

  5. Effect of Nb on barium titanate prepared from citrate solutions

    Directory of Open Access Journals (Sweden)

    Stojanović Biljana D.

    2002-01-01

    Full Text Available The influence of the addition of dopants on the microstructure development and electrical properties of BaTiO3 doped with 0.2, 0.4, 0.6, 0.8 mol% of Nb and 0.01 mol% of Mn based compounds was studied. Doped barium titanate was prepared using the polymeric precursor method from citrate solutions. The powders calcined at 700°C for 4 hours were analysed by infrared (IR spectroscopy to verify the presence of carbonates, and by X-ray diffraction (XRD for phase formation. The phase composition, microstructure and dielectric properties show a strong dependence on the amount of added niobium.

  6. Ionoluminescence of trivalent rare-earth-doped strontium barium niobate

    Energy Technology Data Exchange (ETDEWEB)

    Calvo del Castillo, H. [Departamento de Geologia y Geoquimica, Universidad Autonoma de Madrid, Modulo C-VI, Campus de Cantoblanco, 28049 Cantoblanco, Madrid (Spain); Universidad Nacional Automoma de Mexico, Instituto de Fisica, 04510 Ciudad Universitaria, Mexico D.F. (Mexico); Ruvalcaba, J.L. [Universidad Nacional Automoma de Mexico, Instituto de Fisica, 04510 Ciudad Universitaria, Mexico D.F. (Mexico); Bettinelli, M.; Speghini, A. [Dipartimento Scientifico e Tecnologico, Universita di Verona and INSTM, UdR Verona, Ca Vignal, Strada Le Grazie 15, I-37134 Verona (Italy); Barboza Flores, M. [Centro de Investigacion en Fisica, Universidad de Sonora, Hermosillo, Sonora (Mexico); Calderon, T. [Departamento de Geologia y Geoquimica, Universidad Autonoma de Madrid, Modulo C-VI, Campus de Cantoblanco, 28049 Cantoblanco, Madrid (Spain)], E-mail: tomas.calderon@uam.es; Jaque, D.; Garcia Sole, J. [Departamento de Fisica de Materiales, Universidad Autonoma de Madrid, 28049 Cantoblanco, Madrid (Spain)

    2008-05-15

    Ionoluminescence spectra for different rare-earth ion (Pr{sup 3+} and Eu{sup 3+})-activated Sr{sub x}Ba{sub 1-x}Nb{sub 2}O{sub 6} strontium barium niobate crystals (x=0.33 and 0.60) have been induced with a 3 MeV proton beam for a variety of beam current intensities (45, 40 and 20 nA). The proton-beam induced luminescent spectra have shown features associated with the presence of the rare-earth ion and some spectral features mostly related to the host crystal, which appear only for high beam current intensities. We have compared the ionoluminescence results to those obtained under UV light excitation (photoluminescence technique) where a direct excitation of the band gap would occur.

  7. Microwave absorption properties of barium titanate/epoxide resin composites

    International Nuclear Information System (INIS)

    Nano-barium titanate (BT) was prepared by a sol-gel method. The prepared powders were characterized by x-ray powder diffraction and transmission electron microscopy. The complex relative dielectric permittivity (ε = ε' - jε-prime) and magnetic permeability (μ = μ' - jμ-prime) of the BT powders were measured in the frequency range 8 ∼ 18 GHz. The BT/epoxide resin (EP) composite with different volume contents was investigated. The effects of thickness on the BT/EP composite were studied. It was found that an optimum thickness and contents of the absorber can yield the maximum reflection loss which could be obtained over a broad frequency region in the X and Ku bands. Our results indicate that BT could be a promising microwave absorption material

  8. Study on a flexoelectric microphone using barium strontium titanate

    Science.gov (United States)

    Kwon, S. R.; Huang, W. B.; Zhang, S. J.; Yuan, F. G.; Jiang, X. N.

    2016-04-01

    In this study, a flexoelectric microphone was, for the first time, designed and fabricated in a bridge structure using barium strontium titanate (Ba0.65Sr0.35TiO3) ceramic and tested afterwards. The prototyped flexoelectric microphone consists of a 1.5 mm  ×  768 μm  ×  50 μm BST bridge structure and a silicon substrate with a cavity. The sensitivity and resonance frequency were designed to be 0.92 pC/Pa and 98.67 kHz, respectively. The signal to noise ratio was measured to be 74 dB. The results demonstrate that the flexoelectric microphone possesses high sensitivity and a wide working frequency range simultaneously, suggesting that flexoelectricity could be an excellent alternative sensing mechanism for microphone applications.

  9. Preparation and characterization of magnetic chitosan particles for hyperthermia application

    International Nuclear Information System (INIS)

    The size and shape of magnetic chitosan particles were found to be dependent on both the barium ferrite/chitosan (BF/C) ratio and viscosity of a chitosan solution. The saturation magnetization of magnetic chitosan particles varied directly with the BF/C ratio, while coercivity remained almost constant. Notably, incorporated chitosan was shown to exert substantial activity with regard to low cytotoxicity and high heating rate

  10. Enthalpy of formation of (In, Gd)-doped barium cerate

    International Nuclear Information System (INIS)

    Highlights: • BaCe0.7Gd0.2In0.1O2.85 was prepared by solid-state reaction. • The standard formation enthalpy was determined. • The stabilization energy (ΔstH°) was calculated. • ΔstH° of BaCe0.7Gd0.2In0.1O2.85 is higher than BaCe0.7Nd0.2In0.1O2.85 and BaCeO3. - Abstract: Solution enthalpies of barium cerate doped by gadolinium and indium and a mixture of BaCl2 + 0.7CeCl3 + 2GdCl3 + 0.1InCl3 have been measured in 1 mol dm−3 HCl with 0.1 mol dm−3 KI. For the first time the standard molar formation enthalpy of BaCe0.7Gd0.2In0.1O2.85 has been determined by solution calorimetry as follows: ΔfH° (298.15 K) = −1615.84 ± 9.01 kJ mol−1. The stabilization energy for above-mentioned compound has been calculated as well. It has been shown that barium cerate doped gadolinium and indium has higher stabilization energy than BaCe0.7Nd0.2In0.1O2.85 and BaCeO3. The reaction enthalpy with CO2 interaction has been calculated for BaCe0.7Gd0.2In0.1O2.85

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

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Chuanjian, E-mail: wcjuestc2005@gmail.com, E-mail: ksun@uestc.edu.cn; Yu, Zhong; Sun, Ke, E-mail: wcjuestc2005@gmail.com, E-mail: ksun@uestc.edu.cn; Guo, Rongdi; Jiang, Xiaona; Lan, Zhongwen [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Yang, Yan [Department of Communication and Engineering, Chengdu Technological University, Chengdu 611730 (China)

    2015-09-14

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

  12. Sulfate-reducing bacteria in anaerobic bioreactors.

    OpenAIRE

    Oude Elferink, S.J.W.H.

    1998-01-01

    The treatment of industrial wastewaters containing high amounts of easily degradable organic compounds in anaerobic bioreactors is a well-established process. Similarly, wastewaters which in addition to organic compounds also contain sulfate can be treated in this way. For a long time, the occurrence of sulfate reduction was considered to be undesired. However, there are some recent developments in which sulfate reduction is optimized for the removal of sulfur compounds from waste streams. In...

  13. CLIMATE CHANGE ADAPTATION IN ACID SULFATE LANDSCAPES

    OpenAIRE

    Chuxia Lin

    2012-01-01

    Oxidation of sulfide minerals produces sulfuric acid and consequently creates Acid Sulfate Landscapes (ASLs), which represent one of the most degraded types of land-surface environments. Although acid sulfate-producing weathering is a naturally occurring process, it is markedly facilitated by human intervention. Mining is by far the dominant anthropogenic cause for the creation of inland acid sulfate footprints while land reclamation in coastal lowlands is the driver for the formation of coas...

  14. Methods for sulfate air quality management

    OpenAIRE

    Cass, Glen R.; McMurry, Pamela S.; Houseworth, James E

    1980-01-01

    Executive Summary Abstract: A study of methods for sulfate air quality control strategy design has been conducted. Analytical tools developed were tested within a case study of the nature and causes of the high sulfate concentrations observed in the Los Angeles area. A principal objective was to investigate the least costly means for sulfate air quality improvement in that locale. A long-run average emissions to air quality model was derived which computes pollutant concentrations fr...

  15. Characterisation of Ba(OH){sub 2}–Na{sub 2}SO{sub 4}–blast furnace slag cement-like composites for the immobilisation of sulfate bearing nuclear wastes

    Energy Technology Data Exchange (ETDEWEB)

    Mobasher, Neda; Bernal, Susan A.; Hussain, Oday H. [Immobilisation Science Laboratory, Department of Materials Science and Engineering, The University of Sheffield, Sheffield S1 3JD (United Kingdom); Apperley, David C. [Solid-State NMR Group, Department of Chemistry, Durham University, Durham DH1 3LE (United Kingdom); Kinoshita, Hajime [Immobilisation Science Laboratory, Department of Materials Science and Engineering, The University of Sheffield, Sheffield S1 3JD (United Kingdom); Provis, John L., E-mail: j.provis@sheffield.ac.uk [Immobilisation Science Laboratory, Department of Materials Science and Engineering, The University of Sheffield, Sheffield S1 3JD (United Kingdom)

    2014-12-15

    Soluble sulfate ions in nuclear waste can have detrimental effects on cementitious wasteforms and disposal facilities based on Portland cement. As an alternative, Ba(OH){sub 2}–Na{sub 2}SO{sub 4}–blast furnace slag composites are studied for immobilisation of sulfate-bearing nuclear wastes. Calcium aluminosilicate hydrate (C–A–S–H) with some barium substitution is the main binder phase, with barium also present in the low solubility salts BaSO{sub 4} and BaCO{sub 3}, along with Ba-substituted calcium sulfoaluminate hydrates, and a hydrotalcite-type layered double hydroxide. This reaction product assemblage indicates that Ba(OH){sub 2} and Na{sub 2}SO{sub 4} act as alkaline activators and control the reaction of the slag in addition to forming insoluble BaSO{sub 4}, and this restricts sulfate availability for further reaction as long as sufficient Ba(OH){sub 2} is added. An increased content of Ba(OH){sub 2} promotes a higher degree of reaction, and the formation of a highly cross-linked C–A–S–H gel. These Ba(OH){sub 2}–Na{sub 2}SO{sub 4}–blast furnace slag composite binders could be effective in the immobilisation of sulfate-bearing nuclear wastes.

  16. Sensitivity of single contrast barium enema with regard to colorectal disease as diagnosed by colonoscopy

    International Nuclear Information System (INIS)

    The results of single contrast barium enema were retrospectively correlated with colonoscopically diagnosed colorectal disease in 54 patients (75 lesions). Altogether 66 lesions (88%) were correctly diagnosed. The sensitivity of barium enema for polyps was 81% (26/32). There were three perceptive errors and three polyps 5 mm or less in size were not demonstrated by barium enema. Twenty-nine cases of inflammatory disorders were all correctly diagnosed. One of 12 malignancies was missed by perceptive error. In two cases with vascular malformations the barium enema was normal. 4/9 (44%) of missed lesions were perceptive errors and could have been probably avoided by a second independent reading of films. (orig.)

  17. How changes in a radiologist's technique can reduce patient dose in barium enema studies

    International Nuclear Information System (INIS)

    Changes in a radiologist's technique, especially utilising digital technology, can lead to substantial dose savings in barium enema examinations. Data will be provided showing a 20% saving with only minimal change in technique. (author)

  18. Expanding the 3-O-Sulfate Proteome-Enhanced Binding of Neuropilin-1 to 3-O-Sulfated Heparan Sulfate Modulates Its Activity.

    Science.gov (United States)

    Thacker, Bryan E; Seamen, Emylie; Lawrence, Roger; Parker, Matthew W; Xu, Yongmei; Liu, Jian; Vander Kooi, Craig W; Esko, Jeffrey D

    2016-04-15

    Binding of proteins to heparan sulfate is driven predominantly by electrostatic interactions between positively charged amino acid residues in the protein and negatively charged sulfate groups located at various positions along the polysaccharide chain. Although many heparin/heparan-sulfate-binding proteins have been described, few exhibit preferential binding for heparan sulfates containing relatively rare 3-O-sulfated glucosamine residues. To expand the "3-O-sulfate proteome," affinity matrices were created from Chinese hamster ovary (CHO) cell heparan sulfate engineered in vitro with and without 3-O-sulfate groups. Fractionation of different animal sera yielded several proteins that bound specifically to columns containing 3-O-sulfated heparan sulfate modified by two members of the heparan sulfate 3-O-sulfotransferase superfamily, Hs3st1 and Hs3st2. Neuropilin-1 was analyzed in detail because it has been implicated in angiogenesis and axon guidance. We show that 3-O-sulfation enhanced the binding of neuropilin-1 to heparan sulfate immobilized on plastic plates and to heparan sulfate present on cultured cells. Chemoenzymatically synthesized 3-O-sulfated heparan sulfate dodecamers protected neuropilin-1 from thermal denaturation and inhibited neuropilin-1-dependent, semaphorin-3a-induced growth cone collapse of neurons derived from murine dorsal root ganglia. The effect of 3-O-sulfation was cell autonomous and specific to Hs3st2 based on collapse assays of neurons derived from Hs3st1- and Hs3st2-deficient mice. Finally, 3-O-sulfated heparan sulfate enhanced the inhibition of endothelial cell sprouting by exogenous heparan sulfate. These findings demonstrate a reliable method to identify members of the 3-O-sulfate proteome and that 3-O-sulfation of heparan sulfate can modulate axonal growth cone collapse and endothelial cell sprouting. PMID:26731579

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

    Science.gov (United States)

    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.

  20. Calorimetric study of interaction of barium hydroxide with diluted solutions of hydrofluoric acid

    International Nuclear Information System (INIS)

    Present article is devoted to calorimetric study of interaction of barium hydroxide with diluted solutions of hydrofluoric acid. The calorimetric study of interaction of barium hydroxide with diluted solutions of hydrofluoric acid was carried out in order to determine the thermal effects of reactions. The results of interaction of Ba(OH)4·8H2O with 5, 10, and 20% solution of hydrofluoric acid were considered.

  1. Comparison of barium swallow and ultrasound in diagnosis of gastro-oesophageal reflux in children.

    OpenAIRE

    Naik, D R; Bolia, A; Moore, D. J.

    1985-01-01

    Fifty one infants and older children with suspected gastro-oesophageal reflux entered a study comparing the diagnostic accuracy of a standard barium swallow examination with that of ultrasound scanning. All children were examined by both techniques. In 40 cases there was unequivocal agreement between the examinations. Of the remaining patients, four had definite reflux by ultrasonic criteria but showed no evidence of reflux on barium swallow examination, four had positive findings on ultrasou...

  2. Whipple's disease demonstrated by double contrast small bowel enema with barium and methylcellulose

    International Nuclear Information System (INIS)

    The radiologic findings on small bowel enema examination using barium and methylcellulose (SBE+Ba+MC) in a patient with Whipple's disease before and after treatment are described. The changes on SBE+Ba+MC corresponded well to the clinical and morphologic picture. The advantages of this double contrast technique compared to the enteroclysis with barium alone are demonstrated. The SBE+Ba+MC is a good method to demonstrate the manifestations of Whipple's disease involving the small bowel and the mesentery. (orig.)

  3. Impact of Biofield Treatment on Atomic and Structural Characteristics of Barium Titanate Powder

    OpenAIRE

    Trivedi, Mahendra; Nayak, Gopal

    2015-01-01

    Barium titanate, perovskite structure is known for its high dielectric constant and piezoelectric properties, which makes it interesting material for fabricating capacitors, transducer, actuator, and sensors. The perovskite crystal structure and lattice vibrations play a crucial role in its piezoelectric and ferroelectric behavior. In the present study, the barium titanate powder was subjected to biofield treatment. Further, the control and treated samples were characterized using X-ray diffr...

  4. Kinetics of barium sulphate reaction crystallization in crystallizers with internal circulation

    OpenAIRE

    Koralewska, J.; Piotrowski, K; B. Wierzbowska; A. Matynia

    2008-01-01

    Kinetic calculation results describing the observed nucleation and growth rates of barium sulphate crystals precipitated in an integrated reaction-crystallization process in a barium sulphate-ammonium chloride-water system are presented and analyzed. The scope of experiments included two continuous model DTM-type crystallizers (Draft Tube Magma) with internal circulation of the suspension forced by a liquid jet-pump device responsible for stable and intensive enough ascending/descending flow ...

  5. Atmospheric black carbon and sulfate concentrations in Northeast Greenland

    Directory of Open Access Journals (Sweden)

    A. Massling

    2015-04-01

    Full Text Available Measurements of Black Carbon (BC in aerosols at the high Arctic field site Villum Research Station (VRS at Station Nord in North Greenland showed a seasonal variation in BC concentrations with a maximum in winter and spring at ground level. The data was obtained using a Multi Angle Absorption Photometer (MAAP. A similar seasonal pattern was found for sulfate concentrations with a maximum level during winter and spring analyzed by ion chromatography. A correlation between BC and sulfate concentrations was observed over the years 2011 to 2013. This finding gives the hint that most likely transport of primary emitted BC particles to the Arctic was accompanied by aging of the aerosols through condensational processes. This process may have led to the formation of secondary inorganic matter and further transport of BC particles as cloud processing and further washout of particles is less likely based on the typically observed transport patterns of air masses arriving at VRS. Additionally, concentrations of EC (elemental carbon based on a thermo-optical method were determined and compared to BC measurements. Model estimates of the climate forcing due to BC in the Arctic are based on contributions of long-range transported BC during spring and summer. The measured concentrations were here compared with model results obtained by the Danish Hemispheric Model, DEHM. Good agreement between measured and modeled concentrations of both BC and sulfate was observed. The dominant source is found to be combustion of fossil fuel with biomass burning as a minor though significant source. During winter and spring the Arctic atmosphere is known to be impacted by long-range transport of BC and associated with the Arctic haze phenomenon.

  6. Influence of stoichiometry on phase constitution, thermal behavior and magnetic properties of Ba-hexaferrite particles prepared via SHS route

    International Nuclear Information System (INIS)

    Barium hexaferrite magnetic particles were synthesized via self-propagating high temperature synthesis (SHS) route by thermal initiation of compact mixed powders of iron, iron oxide and barium nitrate using various Fe(total)/Ba molar ratios of 9-12. As-SHS treated and post synthesis specimens were characterized by X-ray powder diffraction, VSM, DTA/TGA and SEM. DTA/TGA studies revealed that the formation temperature of barium hexaferrite decreased by increasing of Fe/Ba molar ratio. VSM measurement also indicated that saturation magnetization (Ms) and coercivity (Hc) of the annealed specimens increased by increasing of Fe/Ba molar ratio. XRD results confirmed by those obtained from DTA/TGA and VSM, indicated that the Fe/Ba molar ratio of 12 is favorable for the formation of single-phase barium hexaferrite

  7. The impact of digital imaging on patient doses during barium studies

    International Nuclear Information System (INIS)

    Barium studies performed on 10 digital and four non-digital fluoroscopic systems were monitored with dose-area product meters as part of a Regional Patient Dosimetry Audit programme. The data have been collected using a computer to read and reset the dose-area product meter and also to collect patient and examination details. A comparison of dose-area product measurements from digital and non-digital fluoroscopy units on over 10 000 barium studies is presented. The data have been corrected according to patient size. The mean size corrected dose-area product for a barium meal examination was found to be 7.62 Gy cm-2 for a digital set compared with 15.45 Gy cm-2 for a non-digital set with 2462 and 1308 patients included in each measurement series, respectively. Dose-area products were also a factor of approximately two lower for barium enema, barium swallow and barium follow-through examinations performed on digital systems. (author)

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

    Science.gov (United States)

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

    2016-01-01

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

  9. Virtual colonoscopy with electron beam CT: correlation with barium enema, colonoscopy and pathology

    International Nuclear Information System (INIS)

    To perform virtual colonoscopy using electron beam tomography(EBT) in patients in whom a colonic mass was present, and to compare the results with those obtained using barium enema, colonoscopy and gross pathologic specimens. Materials and Methods : Ten patients in whom colonic masses were diagnosed by either barium enema or colonoscopy were involved in this study. There were nine cases of adenocarcinoma and one of tubulovillous adenoma. Using EBT preoperative abdominopelvic CT scans were performed. Axial scans were then three-dimensionally reconstructed to produce virtual colonoscopic images and were compared with barium enema, colonoscopy and gross pathologic specimens. Virtual colonoscopic images of the masses were classified as either 1)polyploid, 2)sessile,3)fungating, or 4)annular constrictive. We also determined whether ulcers were present within the lesions and whether there was obstruction. Results : After virtual colonoscopy, two lesions were classified as polyploid, one as sessile, five as fungating and two as annular constrictive. Virtual colonoscopic images showed good correlation with the findings of barium enema, colonoscopy and gross pathologic specimens. Three of six ulcerative lesions were observed on colonoscopy; in seven adenocarcinomas with partial or total luminal obstruction, virtual colonoscopy visualized the colon beyond the obstructed sites. In one case, barium contrast failed to pass through the obstructed portion and in six cases, the colonoscope similarly failed. Conclusion : Virtual colonoscopies correlated well with barium enema, colonoscopy and gross pathologic specimens. They provide three dimensional images of colonic masses and are helpful for the evaluation of obstructive lesions

  10. Synthesis and catalytic activity of polysaccharide templated nanocrystalline sulfated zirconia

    Energy Technology Data Exchange (ETDEWEB)

    Sherly, K. B.; Rakesh, K. [Mahatma Gandhi University Regional Research Center in Chemistry, Department of Chemistry, Mar Athanasius College, Kothamangalam-686666, Kerala (India)

    2014-01-28

    Nanoscaled materials are of great interest due to their unique enhanced optical, electrical and magnetic properties. Sulfate-promoted zirconia has been shown to exhibit super acidic behavior and high activity for acid catalyzed reactions. Nanocrystalline zirconia was prepared in the presence of polysaccharide template by interaction between ZrOCl{sub 2}⋅8H{sub 2}O and chitosan template. The interaction was carried out in aqueous phase, followed by the removal of templates by calcination at optimum temperature and sulfation. The structural and textural features were characterized by powder XRD, TG, SEM and TEM. XRD patterns showed the peaks of the diffractogram were in agreement with the theoretical data of zirconia with the catalytically active tetragonal phase and average crystalline size of the particles was found to be 9 nm, which was confirmed by TEM. TPD using ammonia as probe, FTIR and BET surface area analysis were used for analyzing surface features like acidity and porosity. The BET surface area analysis showed the sample had moderately high surface area. FTIR was used to find the type species attached to the surface of zirconia. UV-DRS found the band gap of the zirconia was found to be 2.8 eV. The benzylation of o-xylene was carried out batchwise in atmospheric pressure and 433K temperature using sulfated zirconia as catalyst.

  11. CLIMATE CHANGE ADAPTATION IN ACID SULFATE LANDSCAPES

    Directory of Open Access Journals (Sweden)

    Chuxia Lin

    2012-01-01

    Full Text Available Oxidation of sulfide minerals produces sulfuric acid and consequently creates Acid Sulfate Landscapes (ASLs, which represent one of the most degraded types of land-surface environments. Although acid sulfate-producing weathering is a naturally occurring process, it is markedly facilitated by human intervention. Mining is by far the dominant anthropogenic cause for the creation of inland acid sulfate footprints while land reclamation in coastal lowlands is the driver for the formation of coastal ASLs. The projected climate change highlights the possibility of an increase in the frequency and severity of extreme weather events such as droughts and heavy rains, which is likely to accelerate the acid generation in some circumstances and increase the frequency and magnitude of acid discharge. Sea level rise as a result of global warming will cause additional problems with the coastal ASLs. This is a review article. The following aspects are covered: (a the overriding biogeochemical processes leading to acid sulfate-producing weathering, (b a brief introduction to the inland acid sulfate landscapes, (c a brief introduction to the coastal acid sulfate landscapes, (d the likely impacts of climate change on ASLs and (e the possible measures to combat climate change-induced environmental degradation in the identified key acid sulfate footprints. The projected climate change is like to significantly affect the acid sulfate landscapes in different ways. Appropriate management strategies and cost-effective technologies need to be developed in order to minimize the climate change-induced ecological degradation.

  12. Rat pro-opiomelanocortin contains sulfate

    Energy Technology Data Exchange (ETDEWEB)

    Hoshina, H.; Hortin, G.; Boime, I.

    1982-07-02

    Intermediate lobes isolated from rat pituitary glands incorporated (/sup 35/S)sulfate into pro-opiomelanocortin and other adrenocorticotropic hormone-containing peptides. Incubation of intermediate lobes in medium containing the arginine analog canavanine inhibited the cleavage of pro-opiomelanocortin into smaller products. Pro-opiomelanocortin that accumulated in the presence of canavanine was also sulfated.

  13. Scintillation properties of lead sulfate

    International Nuclear Information System (INIS)

    We report on the scintillation properties of lead sulfate (PbSO4), a scintillator that show promise as a high energy photon detector. It physical properties are well suited for gamma detection, as its has a density of 6.4 gm/cm3, a 1/e attenuation length for 511 keV photons of 1.2 cm, is not affected by air or moisture, and is cut and polished easily. In 99.998% pure PbSO4 crystals at room temperature excited by 511 keV annihilation photons, the fluorescence decay lifetime contains significant fast components having 1.8 ns (5%) and 19 ns (36%) decay times, but with longer components having 95 ns (36%) and 425 ns (23%) decays times. The peak emission wavelength is 335 nm, which is transmitted by borosilicate glass windowed photomultiplier tubes. The total scintillation light output increases with decreasing temperature fro 3,200 photons/MeV at +45 degrees C to 4, 900 photons/MeV at room temperature (+25 degrees C) and 68,500 photons/MeV at -145 degrees C. In an imperfect, 3 mm cube of a naturally occurring mineral form of PbSO4 (anglesite) at room temperature, a 511 keV photopeak is seen with a total light output of 60% that BGO. There are significant sample to sample variations of the light output among anglesite samples, so the light output of lead sulfate may improve when large synthetic crystals become available. 10 refs

  14. Excess Barium as a Paleoproductivity Proxy: A Reevaluation

    Science.gov (United States)

    Eagle, M.; Paytan, A.

    2001-12-01

    Marine barite may serve as a proxy to reconstruct past export production (Dymond, 1992). In most studies sedimentary barite accumulation is not measured directly, instead a parameter termed excess barium (Baexs), also referred to as biogenic barium, is used to estimate the barite content. Baexs is defined as the total Ba concentration in the sediment minus the Ba associated with terrigenous material. Baexs is calculated by normalization to a constant Ba/Al ratio, typically the average shale ratio. This application assumes that (1) all the Ba besides the fraction associated with terrigenous Al is in the form of barite (the phase related to productivity) (2) the Ba/Alshale is constant in space and time (3) all of the Al is associated with terrigenous matter. If these assumptions are invalidated however, this approach lead to significant errors in calculating export production rates. To test the validity of the use of Baexs as a proxy for barite we compared the Baexs in a wide range of core top sediments from different oceanic settings to the barite content in the same cores. We found that Baexs frequently overestimated the Ba fraction associated with barite and in several cases significant Baexs was measured in the cores where no barite was observed. We have also used a sequential leaching protocol (Collier and Edmond 1984) to determine Ba association with organic matter, carbonates, Fe-Mn hydroxides and silicates. While terrigenous Ba remains an important fraction, in our samples 25-95% of non-barite Ba was derived from other fractions, with Fe-Mn oxides contributing the most Ba. In addition we found that the Ba/Al ratio in the silicate fraction of our samples varied considerably from site to site. The above results suggest that at least two of the underlying assumptions for employing Baexs to reconstruct paleoproductivity are not always valid and previously published data from (Murray and Leinen 1993) indicate that the third assumption may also not hold in every

  15. Analysis of tyrosine-O-sulfation

    DEFF Research Database (Denmark)

    Bundgaard, J.R.; Sen, J.W.; Johnsen, A.H.; Rehfeld, Jens Frederik

    2008-01-01

    Tyrosine O-sulfation was first described about 50 years ago as a post-translational modification of fibrinogen. In the following 30 years it was considered to be a rare modification affecting only a few proteins and peptides. However, in the beginning of the 1980s tyrosine (Tyr) sulfation was shown...... to be a common modification and since then an increasing number of proteins have been identified as sulfated. The target proteins belong to the classes of secretory, plasma membrane, and lysosomal proteins, which reflects the intracellular localization of the enzymes catalyzing Tyr sulfation, the...... to demonstrate the presence of radioactively labeled tyrosine. These techniques have been described in detail previously. The aim of this chapter is to present alternative analytical methods of Tyr sulfation than radioisotope incorporation before analysis Udgivelsesdato: 2008...

  16. Gaseous Sulfate Solubility in Glass: Experimental Method

    Energy Technology Data Exchange (ETDEWEB)

    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.

  17. Modeling of sulfation of potassium chloride by ferric sulfate addition during grate-firing of biomass

    DEFF Research Database (Denmark)

    Wu, Hao; Jespersen, Jacob Boll; Aho, Martti;

    2013-01-01

    Potassium chloride, KCl, formed from critical ash-forming elements released during combustion may lead to severe ash deposition and corrosion problems in biomass-fired boilers. Ferric sulfate, Fe2(SO4)3 is an effective additive, which produces sulfur oxides (SO2 and SO3) to convert KCl to the less...... order to simulate the sulfation of KCl by ferric sulfate addition during grate-firing of biomass. The simulation results show good agreements with the experimental data obtained in a pilot-scale biomass grate-firing reactor, where different amounts of ferric sulfate was injected on the grate or into the...... freeboard. In addition, the simulations of elemental sulfur addition on the grate fit well with the experimental data. The results suggest that the SO3 released from ferric sulfate decomposition is the main contributor to KCl sulfation, and that the effectiveness of the ferric sulfate addition is sensitive...

  18. Uptake of Ambient Organic Gases to Acidic Sulfate Aerosols

    Science.gov (United States)

    Liggio, J.; Li, S.

    2009-05-01

    The formation of secondary organic aerosols (SOA) in the atmosphere has been an area of significant interest due to its climatic relevance, its effects on air quality and human health. Due largely to the underestimation of SOA by regional and global models, there has been an increasing number of studies focusing on alternate pathways leading to SOA. In this regard, recent work has shown that heterogeneous and liquid phase reactions, often leading to oligomeric material, may be a route to SOA via products of biogenic and anthropogenic origin. Although oligomer formation in chamber studies has been frequently observed, the applicability of these experiments to ambient conditions, and thus the overall importance of oligomerization reactions remain unclear. In the present study, ambient air is drawn into a Teflon smog chamber and exposed to acidic sulfate aerosols which have been formed in situ via the reaction of SO3 with water vapor. The aerosol composition is measured with a High Resolution Aerodyne Aerosol Mass Spectrometer (HR-ToF-AMS), and particle size distributions are monitored with a scanning mobility particle sizer (SMPS). The use of ambient air and relatively low inorganic particle loading potentially provides clearer insight into the importance of heterogeneous reactions. Results of experiments, with a range of sulfate loadings show that there are several competing processes occurring on different timescales. A significant uptake of ambient organic gases to the particles is observed immediately followed by a slow shift towards higher m/z over a period of several hours indicating that higher molecular weight products (possibly oligomers) are being formed through a reactive process. The results suggest that heterogeneous reactions can occur with ambient organic gases, even in the presence of ammonia, which may have significant implications to the ambient atmosphere where particles may be neutralized after their formation.

  19. Metabolic Flexibility of Sulfate Reducing Bacteria

    Directory of Open Access Journals (Sweden)

    Caroline M. Plugge

    2011-05-01

    Full Text Available Dissimilatory sulfate-reducing prokaryotes (SRB are a very diverse group of anaerobic bacteria that are omnipresent in nature and play an imperative role in the global cycling of carbon and sulfur. In anoxic marine sediments sulfate reduction accounts for up to 50% of the entire organic mineralization in coastal and shelf ecosystems where sulfate diffuses several meters deep into the sediment. As a consequence, SRB would be expected in the sulfate-containing upper sediment layers, whereas methanogenic Archaea would be expected to succeed in the deeper sulfate-depleted layers of the sediment. Where sediments are high in organic matter, sulfate is depleted at shallow sediment depths, and biogenic methane production will occur. In the absence of sulfate, many SRB ferment organic acids and alcohols, producing hydrogen, acetate, and carbon dioxide, and may even rely on hydrogen- and acetate-scavenging methanogens to convert organic compounds to methane. SRB can establish two different life styles, and these can be termed as sulfidogenic and acetogenic, hydrogenogenic metabolism. The advantage of having different metabolic capabilities is that it raises the chance of survival in environments when electron acceptors become depleted. In marine sediments, SRB and methanogens do not compete but rather complement each other in the degradation of organic matter.Also in freshwater ecosystems with sulfate concentrations of only 10-200 μM, sulfate is consumed efficiently within the top several cm of the sediments. Here, many of the δ-Proteobacteria present have the genetic machinery to perform dissimilatory sulfate reduction, yet they have an acetogenic, hydrogenogenic way of life.In this review we evaluate the physiology and metabolic mode of SRB in relation with their environment.

  20. Activation and transfer of sulfate in biological systems (1960)

    International Nuclear Information System (INIS)

    It examines in this review the successive stages of active sulfate formation and its role in biological synthesis of sulfuric esters. The possible role of active sulfate as intermediary in sulfate reduction is also discussed. (author)

  1. Electrical, optical and vibrational characteristics of nano structured yttrium barium stannous oxide synthesized through a modified combustion method

    International Nuclear Information System (INIS)

    Highlights: → Synthesis of YBa2SnO5.5 nano particles through a novel single step auto igniting combustion process. → Phase purity, thermal stability, vibrational analysis, UV-vis absorption and photo luminescent studies were carried out. → Chemical non-reactivity of YBa2SnO5.5 with high Tc superconductor YBCO was studied. -- Abstract: A single step combustion process for the preparation of nanoparticles of yttrium barium stannous oxide is reported in this paper. The structure, phase purity and particulate properties of the as prepared nano YBa2SnO5.5 powder were examined by X-ray diffraction and transmission electron microscopy. The as prepared powder obtained itself is phase pure and possess cubic structure with lattice constant 8.240 A. The particle size of the as prepared sample from Transmission Electron Microscopy analysis is in the range of ∼15 nm. Vibrational studies carried out on the as prepared powder also confirm the cubic structure of the as prepared sample. The thermal stability of the nano particle is analyzed by thermo gravimetric and differential thermal analysis. The material is a semiconductor with excellent luminescent properties. Chemical compatibility of the sample with YBCO is analyzed. The YBCO-YBa2SnO5.5 composite showed Tc(0) at 92 K.

  2. Surfen, a small molecule antagonist of heparan sulfate

    OpenAIRE

    Schuksz, Manuela; Fuster, Mark M.; Brown, Jillian R.; Crawford, Brett E.; Ditto, David P.; Lawrence, Roger; Glass, Charles A; Wang, Lianchun; Tor, Yitzhak; Esko, Jeffrey D

    2008-01-01

    In a search for small molecule antagonists of heparan sulfate, we examined the activity of bis-2-methyl-4-amino-quinolyl-6-carbamide, also known as surfen. Fluorescence-based titrations indicated that surfen bound to glycosaminoglycans, and the extent of binding increased according to charge density in the order heparin > dermatan sulfate > heparan sulfate > chondroitin sulfate. All charged groups in heparin (N-sulfates, O-sulfates, and carboxyl groups) contributed to binding, consistent with...

  3. Structural and microwave attenuation characteristics of ZnCuY barium ferrites synthesized by a sol–gel auto combustion method

    International Nuclear Information System (INIS)

    Ba2ZnCuFe12O22 (ZnCuY) barium ferrites were prepared using a sol–gel auto combustion method. Mixing the ferrite particles with various sintering temperature from 900 to 1200 °C, ferrite/silicone composite were fabricated. The phase structures, morphologies, magnetic and microwave properties were investigated for the as-prepared samples and the composites. The composites show considerable large permeability with µ′0 of 4.8 and µ″max of 1.7 at resonance frequency of 2.4 GHz. Also, they have good microwave attenuation properties with the percentage bandwidth of 106% for RL<−10 dB in a frequency range of 3–10 GHz with thickness of only 3.7 mm. Therefore, ZnCuY composites could be potential candidates for microwave attenuation applications. - Highlights: • Single phase of Y type barium ferrite prepared by sol gel auto-combustion method were formed at 900 °C and above. • Particle sizes of samples increase with the increase of sintering temperature. • Coercivity measurement reduced dramatically with the increase of sintering temperature. • ZnCuY composites have considerable large permeability values (real and imaginary) at natural resonance frequency of 2.4 GHz. • Two resonance peaks which correspond to natural and wall resonance were found at samples prepared at temperature above 900 °C

  4. Synthesis of nanoparticles of barium strontium titanate using hydrothermal microwave method; Sintese de nanoparticulas de titanato de bario estroncio utilizando o metodo hidrotermal assistido por microondas

    Energy Technology Data Exchange (ETDEWEB)

    Silva, R.A.; Souza, A.E.; Teixeira, S.R. [Universidade Estadual Paulista (DFQB/FCT/UNESP), Presidente Prudente, SP (Brazil). Fac. de Ciencia e Tecnologia. Dept. de Fisica, Quimica e Biologia; Moreira, M.L.; Volanti, D.P. [Universidade Federal de Sao Carlos (LiEC/UFSCAR), SP (Brazil). Lab. Interdisciplinar de Eletroquimica e Ceramica; Longo, E. [Universidade Estadual Paulista (UNESP/LiEC), Araraquara, SP (Brazil). Lab. Interdisciplinar de Eletroquimica e Ceramica

    2009-07-01

    Nanoparticles of barium strontium titanate Ba{sub x}Sr{sub 1}-{sub x}TiO{sub 3} (BST) had been prepared, with x = 0.5, using the hydrothermal method attended by microwaves (HTMW). A solution was prepared using deionized water, barium chloride (BaCl{sub 2}.2H{sub 2}O), strontium chloride (SrCl{sub 2}.6H{sub 2}O), titanium (IV) isopropoxide (C{sub 12}H28O{sub 4}Ti) and potassium hydroxide (KOH). Afterward the solution was heated to 140 deg C in a microwave oven, at a heating rate of 140 deg C/min, and maintained at this temperature for 40 min, under a pressure of 3 to 4 bar. X-ray diffraction (DRX) and field emission scanning electron microscopy (FE-SEM) had been used in the particles characterization. DRX was used to identify the crystallized phases and the images taken from (FE-SEM) show that the material has a wide particle-size distribution with most of them between 10 and 30 nm. (author)

  5. Relative importance of nitrate and sulfate aerosol production mechanisms in urban atmospheres

    International Nuclear Information System (INIS)

    The relative importance of the various sulfate and nitrate aerosol production mechanisms is calculated for different atmospheric conditions. The calculation scheme used to determine the rates of nitrate and sulfate production, based on the concept that vapor transfer to the aerosols and nitrate and sulfate formation within the aerosols are coupled kinetic processes, considers sulfate formation by ozone and hydrogen peroxide oxidation and catalytic oxidation in the presence of soot, iron and manganese of sulfite solutions and sulfuric acid condensation and nitrate formation by the liquid-phase oxidation of dissolved nitrogen oxides for different initial gas concentrations and particle compositions and sizes. It is found that sulfate production is higher under daytime conditions, primarily proceeding by mechanisms involving sulfuric acid and hydrogen peroxide, while at night oxidation processes on the surface of the aerosol film are more important. Nitrate tends to decrease nighttime sulfate production due to an increase in aerosol acidity and nitrate production is found to be higher under nighttime conditions and in the winter

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

    Science.gov (United States)

    Lu, Peizhen Kathy; Mahapatra, Manoj Kumar

    2013-09-24

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

  7. Abundance analysis of s-process enhanced barium stars

    Science.gov (United States)

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

    2016-08-01

    Detailed chemical composition studies of stars with enhanced abundances of neutron-capture elements can provide observational constraints for neutron-capture nucleosynthesis studies and clues for understanding their contribution to the Galactic chemical enrichment. We present abundance results from high-resolution spectral analyses of a sample of four chemically peculiar stars characterized by s-process enhancement. High-Resolution spectra (R ˜42000) of these objects spanning a wavelength range from 4000 to 6800 Å, are taken from the ELODIE archive. We have estimated the stellar atmospheric parameters, the effective temperature Teff, the surface gravity log g, and metallicity [Fe/H] from local thermodynamic equilibrium analysis using model atmospheres. We report estimates of elemental abundances for several neutron-capture elements, Sr, Y, Zr, Ba, La, Ce, Pr, Nd, Sm, Eu and Dy. While HD 49641 and HD 58368 show [Ba/Fe] ≥ 1.16 the other two objects HD 119650 and HD 191010 are found to be mild barium stars with [Ba/Fe] ˜ 0.4. The derived abundances of the elements are interpreted on the basis of existing theories for understanding their origin and evolution.

  8. Structural and magnetic properties of barium-gadolinium hexaferrites

    Energy Technology Data Exchange (ETDEWEB)

    Litsardakis, G. [Department of Electrical and Computer Engineering, Aristotle University of Thessaloniki, Thessaloniki 54124 (Greece)]. E-mail: Lits@eng.auth.gr; Manolakis, I. [Department of Electrical and Computer Engineering, Aristotle University of Thessaloniki, Thessaloniki 54124 (Greece); Serletis, C. [Department of Physics, Aristotle University of Thessaloniki, Thessaloniki 54124 (Greece); Efthimiadis, K.G. [Department of Physics, Aristotle University of Thessaloniki, Thessaloniki 54124 (Greece)

    2007-03-15

    A series of Gd-substituted M-type barium hexaferrites has been prepared by the ceramic route, according to the formula (Ba{sub 1-x}Gd{sub x})O.5.25Fe{sub 2}O{sub 3} (x=0-0.30). XRD analysis revealed that all the samples present primarily an M-type structure. Samples x=0 and x=0.05 are single-phase. Hematite (Fe{sub 2}O{sub 3}) and GdFeO{sub 3} were detected in the remaining samples. Coercivity (H{sub c}) shows remarkably high values, {approx}293kA/m for x=0.20 and 0.30 with a maximum of 322kA/m for x=0.25. Specific saturation magnetization ({sigma}{sub sat}) of the samples presents a small increase up to x=0.10. The microstructure examination indicates that Gd may act as a grain growth inhibitor.

  9. Barium from a mini r-process in supernovae

    Science.gov (United States)

    Heymann, D.

    1983-01-01

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

  10. Properties of barium strontium titanate at millimeter wave frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Osman, Nurul [Department of Physics, Universiti Putra Malaysia (Malaysia); Free, Charles [Department of Engineering and Design, University of Sussex (United Kingdom)

    2015-04-24

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

  11. Properties of barium strontium titanate at millimeter wave frequencies

    International Nuclear Information System (INIS)

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

  12. Radiochemical studies of the sorption behavior of strontium and barium

    International Nuclear Information System (INIS)

    The sorption behavior strontium and barium on kaolinite, bentonite and chlorite-illite mixed clay was studied by radioanalytical techniques using the batch method. 90Sr(29.1 y) and 133Ba(10.5y) were used as radiotracers. Characterization of the solid matrices was done by FTIR and XRD spectrometers and specific surface area measurements. Synthetic groundwater was used as the aqueous phase. The variation of the distribution ratio Rd, as a function of metal ion loading was examined. The sorption isotherms were fitted to various iso term models. The sorption energies were calculated to be in the range of 8-10kJ/mol suggesting an ion exchange type of sorption mechanism. In detailed experiments, chlorite-illite mixed clay was first presatured with K+, Sr2+, Ca2+ and Al 3= ions, respectively, prior to sorption studies with Ba2+ ions. The results of Ca2+ pretreated chlorite-illite were very similar to those of natural chlorite-illite, suggesting that the Ba2+ ion exchanges primarily with the Ca2+ ion on the clay minerals. (author). 15 refs., 3 figs., 5 tabs

  13. Colonic diverticulosis: evaluation with double contrast barium enema

    International Nuclear Information System (INIS)

    To evaluate the pattern of colonic diverticulosis according to age and sex, and recent trend. The authors retrospectively reviewed 120 cases of colonic diverticulosis in 1,020 patients who had undergone a double contrast barium enema examination between January 1st, 1993, and December 31st, 1995, and analyzed the frequency, size, multiplicity and anatomical site, according to age and sex. Diverticulum size was classified into one of three groups : less than 5mm, 5-10mm, over 10mm in diameter. The overall incidence of colonic diverticulosis was 120 cases among 1,020 patients(11.8%) with an incidence 5.3 times higher in males than in females. Peak incidence was in the fifth decade, with 19 cases (15.8%) among males, and after the sixth decade, with four cases(3.3%) among females. Mean age was 57.7 years. Diverticulum size of 5-10mm in diameter was predominant (2% of cases); average diameter was 5-6mm. The incidence of colonic diverticulosis was 5.1 times more frequent in the right colon (101 cases) than in the left (20 cases). The overall incidence of colonic diverticulosis has continually increased; in addition it has also recently increased slightly in left-sided colon. This is thought to be due to various factors, both congenital and acquired, including longer life with good health care, constipation, irritable bowel syndrome, stress and the tendency of eating patterns to more closely resemble those of the west

  14. Colonic diverticulosis: evaluation with double contrast barium enema

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Jae Kook; Lee, Jong Koo; Yun, Eun Joo; Moon, Hee Jung; Shin, Hyun Ja [Korea Veterans Hospital, Seoul (Korea, Republic of)

    1997-02-01

    To evaluate the pattern of colonic diverticulosis according to age and sex, and recent trend. The authors retrospectively reviewed 120 cases of colonic diverticulosis in 1,020 patients who had undergone a double contrast barium enema examination between January 1st, 1993, and December 31st, 1995, and analyzed the frequency, size, multiplicity and anatomical site, according to age and sex. Diverticulum size was classified into one of three groups : less than 5mm, 5-10mm, over 10mm in diameter. The overall incidence of colonic diverticulosis was 120 cases among 1,020 patients(11.8%) with an incidence 5.3 times higher in males than in females. Peak incidence was in the fifth decade, with 19 cases (15.8%) among males, and after the sixth decade, with four cases(3.3%) among females. Mean age was 57.7 years. Diverticulum size of 5-10mm in diameter was predominant (2% of cases); average diameter was 5-6mm. The incidence of colonic diverticulosis was 5.1 times more frequent in the right colon (101 cases) than in the left (20 cases). The overall incidence of colonic diverticulosis has continually increased; in addition it has also recently increased slightly in left-sided colon. This is thought to be due to various factors, both congenital and acquired, including longer life with good health care, constipation, irritable bowel syndrome, stress and the tendency of eating patterns to more closely resemble those of the west.

  15. Barium in landscape components of the western Transbaikal region

    Science.gov (United States)

    Kashin, V. K.

    2015-10-01

    Barium concentrations in parent materials, soils, and plants of the forest-steppe, steppe, and dry steppe landscapes of the Transbaikal region have been studied. The average concentration of this element in rocks and soils of this region exceeds its clarke by 1.8-2.1 times. A positive correlation between the contents of Ba in soils, soil-forming rocks, and plants has been found. The concentration of Ba in soils does not correlate with the soil pH and humus content. Distribution patterns of Ba in the soil profiles have been characterized. With respect to the coefficient of the biological uptake by plants, Ba is assigned to the group of low accumulation (0.55-0.65) for mineral soils and of strong accumulation (6.0) for alluvial bog soils. Average concentrations of Ba in the steppe, meadow, and cultivated vegetation of the region are 1.9-2.3 times higher in comparison with the average concentration of this element in plants of the continents. The biological migration of Ba is most active in meadow landscapes, whereas steppe landscapes are characterized by the least active biological migration of this element.

  16. Abundance analysis of s-process enhanced barium stars

    CERN Document Server

    Mahanta, Upakul; Goswami, Aruna; Duorah, Kalpana

    2016-01-01

    Detailed chemical composition studies of stars with enhanced abundances of neutron-capture elements can provide observational constraints for neutron-capture nucleosynthesis studies and clues for understanding their contribution to the Galactic chemical enrichment. We present abundance results from high-resolution spectral analyses of a sample of four chemically peculiar stars characterized by s-process enhancement. High-Resolution spectra (R ~ 42000) of these objects spanning a wavelength range from 4000 to 6800 A, are taken from the ELODIE archive. We have estimated the stellar atmospheric parameters, the effective temperature T_eff, the surface gravity log g, and metallicity [Fe/H] from local thermodynamic equilibrium analysis using model atmospheres. We report estimates of elemental abundances for several neutron-capture elements, Sr, Y, Zr, Ba, La, Ce, Pr, Nd, Sm, Eu and Dy. While HD 49641 and HD 58368 show [Ba/Fe] > 1.16 the other two objects HD 119650 and HD 191010 are found to be mild barium stars wit...

  17. The thermophysical properties of calcium and barium zirconium phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Gregg, Daniel J., E-mail: daniel.gregg@ansto.gov.au; Karatchevtseva, Inna; Triani, Gerry; Lumpkin, Gregory R.; Vance, Eric R.

    2013-10-15

    The thermophysical and structural properties of calcium and barium zirconium phosphate ceramics (CZP and BZP) have been investigated for their potential candidacy as actinide hosts for inert matrix fuels (IMF) in nuclear reactors. These phosphate ceramics, which can accommodate minor actinides as well as the resulting fission products, are found to be thermally stable to 1600 °C in air, however they begin to decompose in an inert atmosphere above approximately 1400 °C. The heat capacity, thermal conductivity and bulk thermal-expansion were measured from room temperature up to 1200 °C. Structural changes in this temperature region as well as the anisotropic thermal-expansion behaviour were studied using high-temperature X-ray diffraction. A phase change from R-3 to R-3c was identified for Ba{sub 0.5}Zr{sub 2}(PO{sub 4}){sub 3} near 880 °C. The thermal conductivity for these ceramics at 1000 °C was found to be 1.0 W m{sup −1} K{sup −1}, a relatively low thermal conductivity that was increased to 5.0 W m{sup −1} K{sup −1} at 1000 °C for BZP:Ni (25:75 mass ratio) cermet composites.

  18. Preparation and properties of yttria doped tetragonal zirconia polycrystal/Sr-doped barium hexaferrite ceramic composites

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shanshan; Zhang, Chao; Guo, Ruisong, E-mail: rsguo@tju.edu.cn; Liu, Lan; Yang, Yuexia; Li, Kehang

    2015-03-15

    Highlights: • The 3Y-TZP/Sr-doped barium ferrite composites were prepared. • The saturation magnetization was improved by 15% with Sr-doping. • The dispersion coefficient p could reflect the microscopic lattice variation. • The composite with x = 0.5 had the maximum fracture toughness of 8.3 MPa m{sup 1/2}. - Abstract: The effects of substitution of Ba{sup 2+} by Sr{sup 2+} on the magnetic property of barium ferrite and addition barium ferrite secondary phase to the 3 mol% yttria-doped tetragonal zirconia polycrystal (3Y-TZP) matrix on the mechanical property of composites were investigated. The Sr-doped barium ferrite (Ba{sub 1−x}Sr{sub x}Fe{sub 12}O{sub 19}, x = 0, 0.25, 0.50 and 0.75) was synthesized by solid-state reaction in advance. Then 3Y-TZP/20 wt% Sr-doped barium ferrite composites were prepared by means of conventional ceramic method. It was found that a moderate amount of Sr added to barium ferrite could boost the saturation magnetization by 15% compared with the composites without Sr-doping. Besides, the composite with x = 0.50 possessed the best mechanical properties, such as 11.5 GPa for Vickers hardness and 8.3 MPa m{sup 1/2} for fracture toughness, respectively. It was demonstrated that magnetic and mechanical properties of the composites could be harmonized by the incorporation of barium ferrite secondary phase.

  19. Skylab-barium alpha and beta L = 6 field-line tracing experiments

    International Nuclear Information System (INIS)

    Events SKYLAB-BARIUM ALPHA (27 November 1973) and BETA (4 December 1973) were shaped-charge barium field-line tracing experiments near L approximately equal to 6, conducted jointly by the Los Alamos Scientific Laboratory and the University of Alaska Geophysical Institute. Image-orthicon and pulsed intensified auroral cameras provided data for triangulating the fast ion streaks. Using the POGO 10-68, epoch 1965.0, field-line model with Mead-Fairfield corrections for the outer field, the triangulated positions of the fast ion streak were projected down to the 100 km altitude northern conjugate surface. The projected positions moved toward magnetic east with a velocity of 725 m/sec for both SKYLAB-BARIUM ALPHA and BETA. Assuming only an E x B/B2 force, this drift velocity is consistent with an electric field toward magnetic south of 39 mV/m. Radiometric analysis of the filtered, intensified auroral camera records gave observed peak radiance values of about 2 x 10-11 watts/cm2-Sr in the 455.4 nm line of Ba+. The barium in the portion of the ion streak for which radiometric data were obtained had initial injection velocities of 9.5 to 13.5 km/sec in both events. This portion of the ion streak for both SKYLAB-BARIUM ALPHA and BETA contained approximately 4 x 1023 ions compared to the 6.4 x 1024 atoms contained in the barium liner. Ion inventory estimates are based on a solution of the statistical equilibrium equations. Corrections have been made in the ion inventory calculations for Doppler shifts of the solar spectrum as received in the rest frame of the high-velocity barium ions

  20. An 8-year review of barium studies in the diagnosis of gastroparesis

    International Nuclear Information System (INIS)

    Aim: To determine the utility of barium studies for diagnosing gastroparesis in patients with nausea, vomiting, or other related symptoms. Materials and methods: Radiology files revealed gastroparesis without gastric outlet obstruction on upper gastrointestinal tract barium studies in 50 patients with nausea, vomiting, and other related symptoms. Original reports and images were reviewed to determine whether gastric peristalsis was decreased/absent and to investigate gastric dilatation, fluid or debris, and delayed emptying of barium. Twenty patients (40%) had nuclear gastric emptying studies. Medical records were reviewed to determine the presentation, treatment, and course. The diagnosis of gastroparesis was considered accurate if patients with gastroparesis on barium studies responded to treatment. Results: Forty-six patients (92%) had predisposing factors for gastroparesis, including narcotics and diabetes. Forty-five patients (90%) presented with nausea or vomiting, and 40 patients (80%) had one or more other symptoms, including bloating, early satiety, postprandial fullness, and abdominal pain. Barium studies revealed decreased gastric peristalsis in 46 (92%) of the 50 patients and absent peristalsis in four (8%); 46 patients (92%) had additional findings, including gastric dilatation in 30 (60%), delayed emptying of barium in 27 (54%), debris in 28 (56%; bezoars in three), and retained fluid in 13 (26%). Thirteen (65%) of 20 patients with nuclear gastric emptying studies had delayed emptying of solids and seven (35%) had normal emptying. Thirty-five (83%) of 42 patients treated for gastroparesis had symptomatic improvement versus two (25%) of eight patients not treated. Conclusion: Patients with nausea, vomiting, or other related symptoms who have gastroparesis without gastric outlet obstruction on barium studies can be treated for this condition on the basis of the clinical and radiographic findings