Ceria and strontium titanate based electrodes

DEFF Research Database (Denmark)

2010-01-01

A ceramic anode structure obtainable by a process comprising the steps of: (a) providing a slurry by dispersing a powder of an electronically conductive phase and by adding a binder to the dispersion, in which said powder is selected from the group consisting of niobium-doped strontium titanate......, vanadium-doped strontium titanate, tantalum-doped strontium titanate, and mixtures thereof, (b) sintering the slurry of step (a), (c) providing a precursor solution of ceria, said solution containing a solvent and a surfactant, (d) impregnating the resulting sintered structure of step (b...

Strontium-doped calcium silicate bioceramic with enhanced in vitro osteogenic properties.

Science.gov (United States)

No, Young Jung; Roohaniesfahani, Seyediman; Lu, Zufu; Shi, Jeffrey; Zreiqat, Hala

2017-06-05

Gehlenite (GLN, Ca 2 SiAl 2 O 7 ) is a bioceramic that has been recently shown to possess excellent mechanical strength and in vitro osteogenic properties for bone regeneration. Substitutional incorporation of strontium in place of calcium is an effective way to further enhance biological properties of calcium-based bioceramics and glasses. However, such strategy has the potential to affect other important physicochemical parameters such as strength and degradation due to differences in the ionic radius of strontium and calcium. This study is the first to investigate the effect of a range of concentrations of strontium substitution of calcium at 1, 2, 5, 10 mol% (S1-GLN, S2-GLN, S5-GLN and S10-GLN) on the physicochemical and biological properties of GLN. We showed that up to 2 mol% strontium ion substitution retains the monophasic GLN structure when sintered at 1450 °C, whereas higher concentrations resulted in presence of calcium silicate impurities. Increased strontium incorporation resulted in changes in grain morphology and reduced densification when the ceramics were sintered at 1450 °C. Porous GLN, S1-GLN and S2-GLN scaffolds (∼80% porosity) showed compressive strengths of 2.05 ± 0.46 MPa, 1.76 ± 0.79 MPa and 1.57 ± 0.52 MPa respectively. S1-GLN and S2-GLN immersed in simulated body fluid showed increased strontium ion release but reduced calcium and silicon ion release compared to GLN without affecting overall weight loss and pH over a 21 d period. The bioactivity of the S2-GLN ceramics was significantly improved as reflected in the significant upregulation of HOB proliferation and differentiation compared to GLN. Overall, these results suggest that increased incorporation of strontium presents a trade-off between bioactivity and mechanical strength for GLN bioceramics. This is an important consideration in the development of strontium-doped bioceramics.

Antimony doped barium strontium ferrite perovskites as novel cathodes for intermediate-temperature solid oxide fuel cells

Energy Technology Data Exchange (ETDEWEB)

Ling, Yihan, E-mail: lyhyy@mail.ustc.edu.cn [School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou, 221116 (China); Lu, Xiaoyong [China Anhui Key Laboratory of Low Temperature Co-fired Materials, Department of Chemistry, Huainan Normal University, Huainan, Anhui, 232001 (China); Niu, Jinan; Chen, Hui [School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou, 221116 (China); Ding, Yanzhi [China Anhui Key Laboratory of Low Temperature Co-fired Materials, Department of Chemistry, Huainan Normal University, Huainan, Anhui, 232001 (China); Ou, Xuemei [School of Materials Science and Engineering, China University of Mining and Technology, Xuzhou, 221116 (China); Zhao, Ling [Department of Material Science and Chemistry, China University of Geosciences, Wuhan, 430074 (China)

2016-05-05

Antimony was doped to barium strontium ferrite to produce ferrite-based perovskites with a composition of Ba{sub 0.5}Sr{sub 0.5}Fe{sub 1−x}Sb{sub x}O{sub 3−δ} (x = 0.0, 0.05, 0.1) as novel cathode materials for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The perovskite properties including oxygen nonstoichiometry (δ), mean valence of B-site, tolerance factors, thermal expansion coefficient (TEC) and electrical conductivity (σ) are explored as a function of antimony content. By defect chemistry analysis, the TECs decrease since the variable oxygen vacancy concentration is decreased by Sb doping, and σ decreases with x due to the reduced charge concentration of Fe{sup 4+} content. Consequently, the electrochemical performance was substantially improved and the interfacial polarization resistance was reduced from 0.213 to 0.120 Ωcm{sup 2} at 700 °C with Sb doping. The perovskite with x = 1.0 is suggested as the most promising composition as SOFC cathode material. - Highlights: • Antimony is doped to barium strontium ferrite to produce novel cathodes. • δ, TECs and σ are evaluated as a function of antimony content. • The electrochemical performance is substantially improved with antimony doping.

Microstructure and dielectric properties of La2O3 doped Ti-rich barium strontium titanate ceramics for capacitor applications

Directory of Open Access Journals (Sweden)

Zhang Chen

2018-03-01

Full Text Available Microstructure and dielectric properties of La2O3 doped Ti-rich barium strontium titanate ceramics, prepared by solid state method, were investigated with non-stoichiometric level and various La2O3 content, using XRD, SEM and LCR measuring system. With an increase of non-stoichiometric level, the unit cell volumes of perovskite lattices for the single phase Ti-rich barium strontium titanate ceramics increased due to the decreasing A site vacancy concentration V″A. The unit cell volume increased and then decreased slightly with the increasing La2O3 content. Relatively high non-stoichiometric level and high La2O3 content in Ti-rich barium strontium titanate ceramics contributed to the decreased average grain size as well as fine grain size distribution, which correspondingly improved the temperature stability of the relative dielectric constant. The relative dielectric constant єrRT, dielectric loss tanδRT and the maximum relative dielectric constant єrmax decreased and then increased with the increasing non-stoichiometric level. With the increase of La2O3 doping content, the relative dielectric constant єrRT increased initially and then decreased. The maximum relative dielectric constant єrmax can be increased by applying low doping content of La2O3 in Ti-rich barium strontium titanate ceramics due to the increased spontaneous polarization.

Sensitization of Perovskite Strontium Stannate SrSnO3 towards Visible-Light Absorption by Doping

Directory of Open Access Journals (Sweden)

Hungru Chen

2014-01-01

Full Text Available Perovskite strontium stannate SrSnO3 is a promising photocatalyst. However, its band gap is too large for efficient solar energy conversion. In order to sensitize SrSnO3 toward visible-light activities, the effects of doping with various selected cations and anions are investigated by using hybrid density functional calculations. Results show that doping can result in dopant level to conduction band transitions which lie lower in energy compared to the original band gap transition. Therefore, it is expected that doping SrSnO3 can induce visible-light absorption.

Fabrication and Properties of Silica Gel/Calcium Sulfate/Strontium-doped β-tricalcium Phosphate Composite Porous Scaffolds for Bone Tissue Engineering

Directory of Open Access Journals (Sweden)

QIN Xiao-su

2018-03-01

Full Text Available The calcium sulfate/strontium-doped β-tricalcium phosphate composite spherical pellets was fabricated, using the calcium sulfate/strontium-doped β-TCP as raw material, and through the stirring spray drying method, and then composite spherical pellets were combined with silica gel, porous silica gel/calcium sulfate/strontium-doped β-tricalcium phosphate scaffold was obtained by stacking aggregation method in the mould. The XRD, SEM and FT-IR, etc are employed to examine the chemical composition, composite morphology and structure characteristics, and the degradability, porosity, mechanical properties and cytotoxicity of the scaffolds materials were studied. The results reveal that the composite porous scaffolds have irregular pore structure with pore size between 0.2-1.0mm, and they have a large number of micropores on each of the composite spherical pellets, with the aperture between 50-200μm. Moreover, the porosity of the composite scaffolds is about 62%, which can meet the requirements of scaffolds for bone tissue engineering in porosity; the cytotoxicity tests show the composite scaffolds have no cytotoxic effect and it has good degradation. Therefore, it has good application prospect in bone tissue engineering of the bone defect repair of non-bearing site.

Strontium doped injectable bone cement for potential drug delivery applications.

Science.gov (United States)

Taha, Ali; Akram, Muhammad; Jawad, Zaidoon; Alshemary, Ammar Z; Hussain, Rafaqat

2017-11-01

Microwave assisted wet precipitation method was used to synthesize calcium deficient strontium doped β-tricalcium phosphate (Sr-βTCP) with a chemical formula of Ca 2.96-x Sr x (PO 4 ) 2 . Sr-βTCP was reacted with monocalcium phosphate monohydrate [Ca(H 2 PO 4 ) 2 .H 2 O, MCPM] in presence of water to furnish corresponding Sr containing brushite cement (Sr-Brc). The samples were characterized by using X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscopy (FESEM). Strontium content in the prepared samples was determined by using inductively coupled plasma optical emission spectrometry (ICP-OES). The effect of Sr 2+ ions on the structural, mechanical, setting properties and drug release of the cement is reported. Incorporation of Sr 2+ ions improved the injectability, setting time and mechanical properties of the Brc. The release profiles of antibiotics incorporated in Brc and Sr-Brc confirmed that the Sr incorporation into the Brc results in the efficient release of the antibiotics from the cement. Copyright © 2017 Elsevier B.V. All rights reserved.

Novel bone substitute composed of chitosan and strontium-doped α-calcium sulfate hemihydrate: Fabrication, characterisation and evaluation of biocompatibility

International Nuclear Information System (INIS)

Chen, Yirong; Zhou, Yilin; Yang, Shenyu; Li, Jiao Jiao; Li, Xue; Ma, Yunfei; Hou, Yilong; Jiang, Nan; Xu, Changpeng; Zhang, Sheng; Zeng, Rong; Tu, Mei; Yu, Bin

2016-01-01

Calcium sulfate is in routine clinical use as a bone substitute, offering the benefits of biodegradability, biocompatibility and a long history of use in bone repair. The osteoconductive properties of calcium sulfate may be further improved by doping with strontium ions. Nevertheless, the high degradation rate of calcium sulfate may impede bone healing as substantial material degradation may occur before the healing process is complete. The purpose of this study is to develop a novel composite bone substitute composed of chitosan and strontium-doped α-calcium sulfate hemihydrate in the form of microcapsules, which can promote osteogenesis while matching the natural rate of bone healing. The developed microcapsules exhibited controlled degradation that facilitated the sustained release of strontium ions. In vitro testing showed that the microcapsules had minimal cytotoxicity and ability to inhibit bacterial growth. In vivo testing in a mouse model showed the absence of genetic toxicity and low inflammatory potential of the microcapsules. The novel microcapsules developed in this study demonstrated suitable degradation characteristics for bone repair as well as favourable in vitro and in vivo behaviour, and hold promise for use as an alternative bone substitute in orthopaedic surgery. - Highlights: • Chitosan + Sr-doped α-calcium sulfate hemihydrate microcapsules were synthesised. • The novel composite microcapsules had potential application as a bone substitute. • The microcapsules showed controlled degradation and release of strontium ions. • The microcapsules showed in vitro biocompatibility by cytotoxicity test. • The microcapsules showed in vivo biocompatibility in a mouse model.

Novel bone substitute composed of chitosan and strontium-doped α-calcium sulfate hemihydrate: Fabrication, characterisation and evaluation of biocompatibility

Energy Technology Data Exchange (ETDEWEB)

Chen, Yirong; Zhou, Yilin [Department of Orthopaedics and Traumatology, Nanfang Hospital, Southern Medical University, Guangzhou 510515 (China); Yang, Shenyu [Department of Materials Science and Engineering, College of Science and Engineering, Jinan University, Guangzhou 510632 (China); Li, Jiao Jiao [Biomaterials and Tissue Engineering Research Unit, School of AMME, University of Sydney, Sydney, NSW 2006 (Australia); Li, Xue; Ma, Yunfei; Hou, Yilong; Jiang, Nan; Xu, Changpeng; Zhang, Sheng [Department of Orthopaedics and Traumatology, Nanfang Hospital, Southern Medical University, Guangzhou 510515 (China); Zeng, Rong [Department of Materials Science and Engineering, College of Science and Engineering, Jinan University, Guangzhou 510632 (China); Tu, Mei, E-mail: tumei@jnu.edu.cn [Department of Materials Science and Engineering, College of Science and Engineering, Jinan University, Guangzhou 510632 (China); Yu, Bin, E-mail: yubinol@163.com [Department of Orthopaedics and Traumatology, Nanfang Hospital, Southern Medical University, Guangzhou 510515 (China)

2016-09-01

Calcium sulfate is in routine clinical use as a bone substitute, offering the benefits of biodegradability, biocompatibility and a long history of use in bone repair. The osteoconductive properties of calcium sulfate may be further improved by doping with strontium ions. Nevertheless, the high degradation rate of calcium sulfate may impede bone healing as substantial material degradation may occur before the healing process is complete. The purpose of this study is to develop a novel composite bone substitute composed of chitosan and strontium-doped α-calcium sulfate hemihydrate in the form of microcapsules, which can promote osteogenesis while matching the natural rate of bone healing. The developed microcapsules exhibited controlled degradation that facilitated the sustained release of strontium ions. In vitro testing showed that the microcapsules had minimal cytotoxicity and ability to inhibit bacterial growth. In vivo testing in a mouse model showed the absence of genetic toxicity and low inflammatory potential of the microcapsules. The novel microcapsules developed in this study demonstrated suitable degradation characteristics for bone repair as well as favourable in vitro and in vivo behaviour, and hold promise for use as an alternative bone substitute in orthopaedic surgery. - Highlights: • Chitosan + Sr-doped α-calcium sulfate hemihydrate microcapsules were synthesised. • The novel composite microcapsules had potential application as a bone substitute. • The microcapsules showed controlled degradation and release of strontium ions. • The microcapsules showed in vitro biocompatibility by cytotoxicity test. • The microcapsules showed in vivo biocompatibility in a mouse model.

Transformation kinetics in plasma-sprayed barium- and strontium-doped aluminosilicate (BSAS)

International Nuclear Information System (INIS)

Harder, B.J.; Faber, K.T.

2010-01-01

The hexacelsian-to-celsian phase transformation in Ba 1-x Sr x Al 2 Si 2 O 8 is of interest for environmental barrier coating applications. Plasma-sprayed microstructures were heat treated above 1100 o C and the kinetics of the hexacelsian-to-celsian transformation were quantified. Activation energies for bulk and crushed materials were determined to be ∼340 and ∼500 kJ mol -1 , respectively. X-ray diffraction and electron backscattered diffraction were used to establish how plasma spraying barium- and strontium-doped aluminosilicate effectively reduces the energy required for its transformation.

Synthesis and characterization of nanoporous strontium-doped lanthanum cobaltite thin film using metal organic chemical solution deposition

Energy Technology Data Exchange (ETDEWEB)

Park, Jun-Sik [Department of Mechanical Convergence Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Kim, Young-Beom, E-mail: ybkim@hanyang.ac.kr [Department of Mechanical Convergence Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Institute of Nano Science and Technology, Hanyang University, Seoul 133-791 (Korea, Republic of)

2016-01-29

By employing strontium as a dopant of lanthanum cobaltite (LaCoO{sub 3}), strontium-doped lanthanum cobaltite (La{sub 1−x}Sr{sub x}CoO{sub 3−δ}, LSC) thin film was fabricated using a metal organic chemical solution deposition (MOCSD) method. Lanthanum nitrate hexahydrate [La(NO{sub 3}){sub 3}6H{sub 2}O], strontium acetate [Sr(CH{sub 3}COO){sub 2}], and cobalt acetate tetrahydrate [Co(CH{sub 3}COO){sub 2}4H{sub 2}O] were used as precursors. The coating process was performed through a spin coating method on a substrate, which were then heat treated under various temperature conditions. Electrical properties, microstructures, and crystalline structures with respect to sintering temperature were analyzed. According to these analyses, the change in surface morphology, phase shift, and conductive properties were closely related, which could explain their respective behaviors. Furthermore, sintered strontium-doped lanthanum perovskite oxides showed various conductivities according to the amount of dopant. With the molar ratio of strontium that is stoichiometrically equivalent to lanthanum (La{sub 0.5}Sr{sub 0.5}CoO{sub 3−δ}) thin film showed the best conductivity in the sintering temperature range of 650–700 °C, with perovskite phases formed at this temperature condition. As the electrically conductive properties of the thin film are a function of thickness, the films were coated several times to a thickness of approximately 300 nm, with the lowest resistivity (approximately 9.06 × 10{sup −4} Ω cm) observed at the optimized sintering temperature and solution composition. - Highlights: • LSC thin film was fabricated by metal organic chemical solution deposition (MOCSD). • The film shows good agreement on the electrical conductivity of LSC by conventional methods. • The properties of LSC film are influenced by the surface morphology and crystalline phase. • Optimal molar ratio of strontium for the highest conductivity was investigated.

Enhancement of tetragonality and role of strontium vacancies in heterovalent doped SrTiO.sub.3./sub..

Czech Academy of Sciences Publication Activity Database

Tkach, A.; Almeida, A.; Moreira, J.A.; Correia, T.M.; Chaves, M. R.; Okhay, O.; Vilarinho, P. M.; Gregora, Ivan; Petzelt, Jan

2011-01-01

Roč. 98, č. 5 (2011), "052903-1"-"052903-2" ISSN 0003-6951 R&D Projects: GA AV ČR KAN301370701 Institutional research plan: CEZ:AV0Z10100520 Keywords : strontium titanate * doping * phase transition * Raman spectroscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.844, year: 2011

Amino acid-assisted synthesis of strontium hydroxyapatite bone ...

Indian Academy of Sciences (India)

Strontium-incorporated calcium phosphates show potential in biomedical application, particularly the doped stron- tium may ... shows that the addition of glycine plays an important role in reducing the particle size of strontium hydroxyapatite.

Strontium-Doped Hematite as a Possible Humidity Sensing Material for Soil Water Content Determination

OpenAIRE

Tulliani, Jean-Marc; Baroni, Chiara; Zavattaro, Laura; Grignani, Carlo

2013-01-01

The aim of this work is to study the sensing behavior of Sr-doped hematite for soil water content measurement. The material was prepared by solid state reaction from commercial hematite and strontium carbonate heat treated at 900 °C. X-Ray diffraction, scanning electron microscopy and mercury intrusion porosimetry were used for microstructural characterization of the synthesized powder. Sensors were then prepared by uniaxially pressing and by screen-printing, on an alumina substrate, the prep...

A comparative study of strontium and titanium doped mullite in PVDF matrix and their phase behavior, microstructure and electrical properties

Energy Technology Data Exchange (ETDEWEB)

Paul, Biplab Kumar; Roy, Debasis; Batabyal, Sreejita [Department of Physics, Jadavpur University, Kolkata 700 032 (India); Bhattacharya, Alakananda [West Bengal State University, Kolkata (India); Nandy, Papiya [Department of Physics, Jadavpur University, Kolkata 700 032 (India); Das, Sukhen, E-mail: sdasphysics@gmail.com [Department of Physics, Jadavpur University, Kolkata 700 032 (India); Indian Institute of Engineering Science and Technology, Shibpur (India)

2017-02-01

We have discussed the dielectric behavior, phase behavior, microstructure and electrical properties of strontium and titanium induced aluminno-silicate ceramic composite system doped in PVDF (Polyvinyliden fluoride) matrix, with different molar concentration of titanium and strontium salts prepared via sol-gel route. The frequency dispersions of permittivity, conductivity and dissipation factor were investigated in detail. This paper demonstrates that the loading of a conductive component into a highly insulating matrix is an effective way to fabricate composites with simultaneously high permittivity. The incorporation of these metal doped mullite composites on PVDF can be used as dielectric material for the fabrication of high charge storing multilayer capacitors and also a promising candidate for electronic industries. - Highlights: • We have synthesized mullite composites with high dielectric constants. • High charge storing multilayer capacitors require a material with high dielectric constant. • The material developed will be perfect for the applications of embedded capacitors. • The material we have synthesized is a promising candidate for electronic industries.

Gas thermodesorption study of barium and strontium cerates

International Nuclear Information System (INIS)

Aksenova, T.I.; Khromushin, I.V.; Zhotabaev, Zh.R.; Bukenov, K.D.; Medvedeva, Z.V.; Berdauletov, A.K.

2002-01-01

Kinetic of water, oxygen, hydrogen and carbon dioxide molecules release from doped and undoped samples of barium cerates and doped strontium cerates during vacuum heating was studied. The samples were prepared by inductive melting method. The following two kinds of preliminary samples treatments were used: annealing in air (650-750 deg. C) and wet nitrogen atmosphere (625 deg.C). Main results of thermodesorption studies of barium and strontium cerates are represented in the table. The samples of doped LaSrMnO were investigated also. It was found that the initial doped samples (without preliminary annealing) did not show any gas release in temperature range of 20-1100 deg. C. This fact indicates on high stability of compositions and strong bond of 'host' oxygen in their lattice. A significant amount of water and oxygen molecules were released from BaCe 0.9 Nd 0.1 O 3 samples whereas water and hydrogen molecules desorption from SrCe 0.95 Y 0.05 O 3 samples took place. Hydrogen molecules desorption was found for strontium cerates samples; no hydrogen molecules release was observed for doped and pure barium cerate samples.Intensive water molecules release from doped samples confirms the necessity of oxygen vacancies creation in these compounds to get properties of proton conductivity, since it was not found any water molecules release from annealed undoped samples of BaCeO 3 It is necessary to notice that oxygen molecules release from these samples took place at ∼1000 deg. C that is significantly higher then from BaCeNdO samples. Forms of high temperatures part of oxygen and low temperature part of water spectra indicate that phase transformations are responsible for oxygen and water molecules desorption in this cases. These results are in good agreement with literature data. Desorption of water molecules from barium and strontium cerates took place. Oxygen desorption took place only from barium cerates. It can be explained as the following: doped barium cerates have

Thermal conductivity reduction in oxygen-deficient strontium titanates

NARCIS (Netherlands)

Yu, Choongho; Scullin, Matthew L.; Huijben, Mark; Ramesh, Ramamoorthy; Majumdar, Arun

2008-01-01

We report significant thermal conductivity reduction in oxygen-deficient lanthanum-doped strontium titanate (Sr1−xLaxTiO3−δ) films as compared to unreduced strontium titanates. Our experimental results suggest that the oxygen vacancies could have played an important role in the reduction. This could

Atom states and interatomic interactions in complex perovskite-like oxides. Communication XX. Origin of electron-ionic conductivity in lanthanum gallates doped with strontium and chromium

International Nuclear Information System (INIS)

Chezhina, N.V.; Zolotukhina, N.V.; Pijr, I.V.

2006-01-01

Magnetic susceptibilities and electric conductivities of solid solutions based on lanthanum gallate containing chromium and strontium atoms in the ratio of 10 : 2 were studied. It was shown that no partial oxidation of chromium to Cr(IV) occurs when lanthanum gallate is doped with chromium and strontium simultaneously, whereas the ionic conductivity is associated with the appearance of vacancies stabilized by chromium atoms in the oxygen sublattice [ru

Elaboration and characterization of fluorohydroxyapatite and fluoroapatite sol−gel coatings on CoCrMo alloy

Energy Technology Data Exchange (ETDEWEB)

Romonţi, D. Covaciu [University “Politehnica” of Bucharest, Faculty of Applied Chemistry and Materials Science 1-7, Polizu Str., 011061, Bucharest (Romania); Iskra, J. [Jožef Stefan Institute, Department of Physical and Organic Chemistry, Jamova 39, SI-6280 (Slovenia); Bele, M. [National Institute of Chemistry, Laboratory for Materials Chemistry, Hajdrihova 19, SI-1000 Ljubljana (Slovenia); Demetrescu, I. [University “Politehnica” of Bucharest, Faculty of Applied Chemistry and Materials Science 1-7, Polizu Str., 011061, Bucharest (Romania); Milošev, I., E-mail: ingrid.milosev@ijs.si [Jožef Stefan Institute, Department of Physical and Organic Chemistry, Jamova 39, SI-6280 (Slovenia)

2016-04-25

The surface of CoCrMo alloy used in orthopedic and dental applications was modified in order to improve its osseointegration. Fluorohydroxyapatite and fluoroapatite coatings were prepared by the sol–gel procedure and deposited on CoCrMo substrate by immersion. The steps of sol–gel synthesis were studied using Fourier transform infrared spectroscopy. The surfaces of the coatings were characterized using scanning electron microscopy and X-ray diffraction. The electrochemical properties of coatings were tested in Fusayama artificial saliva using polarization measurements. The most stable coating was fluorohydroxyapatite. It also has the strongest adhesion. - Highlights: • Fluorohydroxyapatite and fluoroapatite coatings were deposited by sol–gel process. • Synthesis was optimized in situ using Fourier transform infrared spectroscopy. • Coatings provide corrosion protection of CoCrMo substrate in artificial saliva. • Coatings are macroscopically dense, homogeneous and adhere well to the substrate.

Elaboration and characterization of fluorohydroxyapatite and fluoroapatite sol−gel coatings on CoCrMo alloy

International Nuclear Information System (INIS)

Romonţi, D. Covaciu; Iskra, J.; Bele, M.; Demetrescu, I.; Milošev, I.

2016-01-01

The surface of CoCrMo alloy used in orthopedic and dental applications was modified in order to improve its osseointegration. Fluorohydroxyapatite and fluoroapatite coatings were prepared by the sol–gel procedure and deposited on CoCrMo substrate by immersion. The steps of sol–gel synthesis were studied using Fourier transform infrared spectroscopy. The surfaces of the coatings were characterized using scanning electron microscopy and X-ray diffraction. The electrochemical properties of coatings were tested in Fusayama artificial saliva using polarization measurements. The most stable coating was fluorohydroxyapatite. It also has the strongest adhesion. - Highlights: • Fluorohydroxyapatite and fluoroapatite coatings were deposited by sol–gel process. • Synthesis was optimized in situ using Fourier transform infrared spectroscopy. • Coatings provide corrosion protection of CoCrMo substrate in artificial saliva. • Coatings are macroscopically dense, homogeneous and adhere well to the substrate.

Electrochemically assisted deposition of strontium modified magnesium phosphate on titanium surfaces

International Nuclear Information System (INIS)

Meininger, M.; Wolf-Brandstetter, C.; Zerweck, J.; Wenninger, F.; Gbureck, U.; Groll, J.; Moseke, C.

2016-01-01

Electrochemically assisted deposition was utilized to produce ceramic coatings on the basis of magnesium ammonium phosphate (struvite) on corundum-blasted titanium surfaces. By the addition of defined concentrations of strontium nitrate to the coating electrolyte Sr 2+ ions were successfully incorporated into the struvite matrix. By variation of deposition parameters it was possible to fabricate coatings with different kinetics of Sr 2+ into physiological media, whereas the release of therapeutically relevant strontium doses could be sustained over several weeks. Morphological and crystallographic examinations of the immersed coatings revealed that the degradation of struvite and the release of Sr 2+ ions were accompanied by a transformation of the coating to a calcium phosphate based phase similar to low-crystalline hydroxyapatite. These findings showed that strontium doped struvite coatings may provide a promising degradable coating system for the local application of strontium or other biologically active metal ions in the implant–bone interface. - Highlights: • Sr-doped struvite coatings have been deposited on titanium by electrochemically assisted deposition. • Sr content can be adjusted by means of process time, current density and pulse mode. • Sr-doped coatings release therapeutically relevant Sr doses in physiological media for several weeks. • During immersion in physiological media Sr-doped struvite coatings transform into a low crystalline calcium phosphate phase.

The effect of strontium doping on structural and morphological properties of ZnO nanofilms synthesized by ultrasonic spray pyrolysis method

Directory of Open Access Journals (Sweden)

A. Ouhaibi

2018-03-01

Full Text Available Pristine and strontium doped ZnO nanometric films were successfully synthesized on heated glass substrates by the ultrasonic spray pyrolysis technique. The samples were characterized by means of X-ray diffraction (XRD, Atomic Force Microscope (AFM, UV–visible spectroscopy and photoluminescence (PL. X-ray diffraction patterns confirmed the hexagonal (wurtzite structure, where the most pronounced (002 peak indicates the preferential orientation along the c-axis perpendicular to the sample surface. The intensity of this peak was increased rapidly from the first doping of 1% and its position was shifted toward higher angles under Sr-doping effect. For the used doping range of 1–5%, the Sr-doping at 3% attracted an especial attention. At this concentration, the particular transformation in the surface morphology of doped ZnO films was observed. The surface became granular and rough by expanding the crystallites' size. From optical measurements, transmittance and PL spectra were found to be sensitive to Sr-doping, where two different behaviors were observed before and after 3% of Sr-doping. Keywords: Ultrasonic spray pyrolysis, Sr-doped ZnO, Morphology study, Optical properties

Electrochemically assisted deposition of strontium modified magnesium phosphate on titanium surfaces

Energy Technology Data Exchange (ETDEWEB)

Meininger, M. [Department for Functional Materials in Medicine and Dentistry, University of Würzburg, Pleicherwall 2, D-97070 Würzburg (Germany); Wolf-Brandstetter, C. [Max Bergmann Center for Biomaterials, Technical University of Dresden, Budapester Straße 27, D-01069 Dresden (Germany); Zerweck, J.; Wenninger, F.; Gbureck, U.; Groll, J. [Department for Functional Materials in Medicine and Dentistry, University of Würzburg, Pleicherwall 2, D-97070 Würzburg (Germany); Moseke, C., E-mail: claus.moseke@fmz.uni-wuerzburg.de [Department for Functional Materials in Medicine and Dentistry, University of Würzburg, Pleicherwall 2, D-97070 Würzburg (Germany)

2016-10-01

Electrochemically assisted deposition was utilized to produce ceramic coatings on the basis of magnesium ammonium phosphate (struvite) on corundum-blasted titanium surfaces. By the addition of defined concentrations of strontium nitrate to the coating electrolyte Sr{sup 2+} ions were successfully incorporated into the struvite matrix. By variation of deposition parameters it was possible to fabricate coatings with different kinetics of Sr{sup 2+} into physiological media, whereas the release of therapeutically relevant strontium doses could be sustained over several weeks. Morphological and crystallographic examinations of the immersed coatings revealed that the degradation of struvite and the release of Sr{sup 2+} ions were accompanied by a transformation of the coating to a calcium phosphate based phase similar to low-crystalline hydroxyapatite. These findings showed that strontium doped struvite coatings may provide a promising degradable coating system for the local application of strontium or other biologically active metal ions in the implant–bone interface. - Highlights: • Sr-doped struvite coatings have been deposited on titanium by electrochemically assisted deposition. • Sr content can be adjusted by means of process time, current density and pulse mode. • Sr-doped coatings release therapeutically relevant Sr doses in physiological media for several weeks. • During immersion in physiological media Sr-doped struvite coatings transform into a low crystalline calcium phosphate phase.

Novel strontium-doped bioactive glass nanoparticles enhance proliferation and osteogenic differentiation of human bone marrow stromal cells

Energy Technology Data Exchange (ETDEWEB)

Strobel, L. A. [University of Erlangen-Nuremberg Medical Center, Department of Plastic and Hand Surgery (Germany); Hild, N.; Mohn, D.; Stark, W. J. [ETH Zurich, Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering (Switzerland); Hoppe, A. [University of Erlangen-Nuremberg, Department of Materials Science and Engineering, Institute of Biomaterials (Germany); Gbureck, U. [University of Wuerzburg, Department for Functional Materials in Medicine and Dentistry (Germany); Horch, R. E.; Kneser, U. [University of Erlangen-Nuremberg Medical Center, Department of Plastic and Hand Surgery (Germany); Boccaccini, A. R., E-mail: aldo.boccaccini@ww.uni-erlangen.de [University of Erlangen-Nuremberg, Department of Materials Science and Engineering, Institute of Biomaterials (Germany)

2013-07-15

The present study investigates a new family of bioactive glass nanoparticles with and without Sr-doping focusing on the influence of the nanoparticles on human bone marrow stromal cells (hBMSCs) in vitro. The bioactive glass nanoparticles were fabricated by flame spray synthesis and a particle diameter of 30-35 nm was achieved. Glass nanoparticles were undoped (BG 13-93-0Sr) or doped with 5 wt% strontium (Sr) (BG 13-93-5Sr) and used at concentrations of 10 and 100 {mu}g/cm Superscript-Two (particles per culture plate area), respectively. Cells were cultured for 14 days after which the samples were analysed regarding metabolic activity and expression of various bone-specific genes. Cell growth and morphology indicated the high cytocompatibility of the nanoparticulate bioactive glass. The presence of the nanoparticles enhanced cell growth compared to the plain polystyrene control group. At a concentration of 100 {mu}g/cm Superscript-Two , Sr-doped particles led to significantly enhanced gene expression of osteocalcin, collagen type 1 and vascular endothelial growth factor. Thus, Sr-doped nanoparticles showing a dose-dependent increase of osteogenic differentiation in hBMSCs are a promising biomaterial for bone regeneration purposes.

Novel strontium-doped bioactive glass nanoparticles enhance proliferation and osteogenic differentiation of human bone marrow stromal cells

International Nuclear Information System (INIS)

Strobel, L. A.; Hild, N.; Mohn, D.; Stark, W. J.; Hoppe, A.; Gbureck, U.; Horch, R. E.; Kneser, U.; Boccaccini, A. R.

2013-01-01

The present study investigates a new family of bioactive glass nanoparticles with and without Sr-doping focusing on the influence of the nanoparticles on human bone marrow stromal cells (hBMSCs) in vitro. The bioactive glass nanoparticles were fabricated by flame spray synthesis and a particle diameter of 30–35 nm was achieved. Glass nanoparticles were undoped (BG 13-93-0Sr) or doped with 5 wt% strontium (Sr) (BG 13-93-5Sr) and used at concentrations of 10 and 100 μg/cm² (particles per culture plate area), respectively. Cells were cultured for 14 days after which the samples were analysed regarding metabolic activity and expression of various bone-specific genes. Cell growth and morphology indicated the high cytocompatibility of the nanoparticulate bioactive glass. The presence of the nanoparticles enhanced cell growth compared to the plain polystyrene control group. At a concentration of 100 μg/cm², Sr-doped particles led to significantly enhanced gene expression of osteocalcin, collagen type 1 and vascular endothelial growth factor. Thus, Sr-doped nanoparticles showing a dose-dependent increase of osteogenic differentiation in hBMSCs are a promising biomaterial for bone regeneration purposes

Novel strontium-doped bioactive glass nanoparticles enhance proliferation and osteogenic differentiation of human bone marrow stromal cells

Science.gov (United States)

Strobel, L. A.; Hild, N.; Mohn, D.; Stark, W. J.; Hoppe, A.; Gbureck, U.; Horch, R. E.; Kneser, U.; Boccaccini, A. R.

2013-07-01

The present study investigates a new family of bioactive glass nanoparticles with and without Sr-doping focusing on the influence of the nanoparticles on human bone marrow stromal cells (hBMSCs) in vitro. The bioactive glass nanoparticles were fabricated by flame spray synthesis and a particle diameter of 30-35 nm was achieved. Glass nanoparticles were undoped (BG 13-93-0Sr) or doped with 5 wt% strontium (Sr) (BG 13-93-5Sr) and used at concentrations of 10 and 100 μg/cm² (particles per culture plate area), respectively. Cells were cultured for 14 days after which the samples were analysed regarding metabolic activity and expression of various bone-specific genes. Cell growth and morphology indicated the high cytocompatibility of the nanoparticulate bioactive glass. The presence of the nanoparticles enhanced cell growth compared to the plain polystyrene control group. At a concentration of 100 μg/cm², Sr-doped particles led to significantly enhanced gene expression of osteocalcin, collagen type 1 and vascular endothelial growth factor. Thus, Sr-doped nanoparticles showing a dose-dependent increase of osteogenic differentiation in hBMSCs are a promising biomaterial for bone regeneration purposes.

Development, characterization and comparison of two strontium doped nano hydroxyapatite molecules for enamel repair/regeneration.

Science.gov (United States)

Krishnan, Vinod; Bhatia, Ankit; Varma, Harikrishna

2016-05-01

Enamel damage resulting or arising from/associated with orthodontic treatment such as white spot lesions and surface deterioration after debonding brackets along with incipient carious lesions are considered problems not amenable for routine restorations due to its invasive nature. The present study was aimed at synthesizing and characterizing nHAp and 25 and 50 mol% strontium nHAp as a surface application modality for dental enamel remineralization/repair. 25 and 50 mol% Sr nHAp was synthesized and characterized in comparison with custom made pure nHAp initially with the help of transmission and scanning electron microscopy as well as toxicological assessment. Further, comparative evaluation of these novel synthesized strontium substituted particles was assessed for its efficacy in repairing damaged enamel with the help of atomic force microscopy, scanning electron microscopy and micro indentation testing. There is increase in crystallinity and reduced particle size favoring dissolution and re-precipitation through small incipient carious lesions and soft white spot areas with 25% Sr-nHAp. Sr doped specimens showed more cell viability in comparison with pure nHAP make it less cytotoxic and hence a biologically friendly material which can be safely applied in patient's mouth. AFM images obtained from 25% and 50% Sr nHAp treated specimens clearly indicated increased roughness in surface topography and performed well with micro indentation test. The novel synthesized Sr doped nHAp forms an improved treatment modality to tackle the long standing quest for solving the problem of enamel loss with incipient carious lesions and WSL from orthodontic procedures. Copyright © 2016 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Study on the piezoelectric behavior and structural changes of strontium doped PZT

International Nuclear Information System (INIS)

Silva, M.S. da; Lemos, L.; Souza, E.F.; Cavalheiro, A.A.; Longo, E.; Zaghete, M.A.

2014-01-01

Lead zirconate titanate, with Zr/Ti ratio of 53/47 was prepared by the polymeric precursor method. The powders were doped with 0.0, 0.2, 0.4 and 0.6 mol% of Sr 2+ and the effects of Sr 2+ additions on piezoelectric properties and on the phase constitution were investigated by XRD. The percentages of tetragonal and rhombohedral phases were calculated through Rietveld refinement. The results indicated that addition of Sr 2+ ions in the amount of 0.4 mol% in the ceramic structure maximally increase the values of piezoelectric parameter to d 33 = 289 μC/N and K p = 0.43. The values found for the piezoelectric properties were among the highest at the concentration of 0.4 mol% of strontium and this composition showed the highest structural change from the rhombohedral to the tetragonal phase perovskita. (author)

High temperature dielectric relaxation anomaly of Y3+ and Mn2+ doped barium strontium titanate ceramics

International Nuclear Information System (INIS)

Yan, Shiguang; Mao, Chaoliang; Wang, Genshui; Yao, Chunhua; Cao, Fei; Dong, Xianlin

2014-01-01

Relaxation like dielectric anomaly is observed in Y 3+ and Mn 2+ doped barium strontium titanate ceramics when the temperature is over 450 K. Apart from the conventional dielectric relaxation analysis method with Debye or modified Debye equations, which is hard to give exact temperature dependence of the relaxation process, dielectric response in the form of complex impedance, assisted with Cole-Cole impedance model corrected equivalent circuits, is adopted to solve this problem and chase the polarization mechanism in this paper. Through this method, an excellent description to temperature dependence of the dielectric relaxation anomaly and its dominated factors are achieved. Further analysis reveals that the exponential decay of the Cole distribution parameter n with temperature is confirmed to be induced by the microscopic lattice distortion due to ions doping and the interaction between the defects. At last, a clear sight to polarization mechanism containing both the intrinsic dipolar polarization and extrinsic distributed oxygen vacancies hopping response under different temperature is obtained.

Multicomponent doped barium strontium titanate thin films for tunable microwave applications

Science.gov (United States)

Alema, Fikadu Legesse

In recent years there has been enormous progress in the development of barium strontium titanate (BST) films for tunable microwave applications. However, the properties of BST films still remain inferior compared to bulk materials, limiting their use for microwave technology. Understanding the film/substrate mismatch, microstructure, and stoichiometry of BST films and finding the necessary remedies are vital. In this work, BST films were deposited via radio frequency magnetron sputtering method and characterized both analytically and electrically with the aim of optimizing their properties. The stoichiometry, crystal structure, and phase purity of the films were studied by varying the oxygen partial pressure (OPP) and total gas pressure (TGP) in the chamber. A better stoichiometric match between film and target was achieved when the TGP is high (> 30 mTorr). However, the O2/Ar ratio should be adjusted as exceeding a threshold of 2 mTorr in OPP facilitates the formation of secondary phases. The growth of crystalline film on platinized substrates was achieved only with a lower temperature grown buffer layer, which acts as a seed layer by crystallizing when the temperature increases. Concurrent Mg/Nb doping has significantly improved the properties of BST thin films. The doped film has shown an average tunability of 53%, which is only ˜8 % lower than the value for the undoped film. This drop is associated with the Mg ions whose detrimental effects are partially compensated by Nb ions. Conversely, the doping has reduced the dielectric loss by ˜40 % leading to a higher figure of merit. Moreover, the two dopants ensure a charge neutrality condition which resulted in significant leakage current reduction. The presence of large amounts of empty shallow traps related to Nb Ti localize the free carriers injected from the contacts; thus increase the device control voltage substantially (>10 V). A combinatorial thin film synthesis method based on co-sputtering of two BST

Gelcasting of strontium doped lanthanum manganite for solid oxide fuel cell applications

International Nuclear Information System (INIS)

Abdul Haleem, B.; Bhuvana, R.; Udayakumar, A.

2009-01-01

Solid oxide fuel cells (SOFCs) are devices that offer high efficiency power output with negligible emissions. Cathode supported tubular SOFCs consist of porous cathode tubes made up of strontium doped lanthanum manganite, La 1-x Sr x MnO 3 (LSM) that work as functional component as well as structural support for the rest of the cell components. Gelcasting is one of the most suitable methods for the fabrication of porous ceramics. This paper describes the fabrication of porous LSM cathode by gelcasting process. Gelcasting parameters such as monomer concentration, powder volume fraction, pH of the slurry, etc were optimized. Slow drying of green specimens minimized warpage and cracking. Sintered specimens with controlled porosity were obtained by the use of suitable pore-forming agents. The coefficient of thermal expansion (CTE) of sintered specimens was measured, which was found matching with the CTE values of cell components reported in the literature. These results have shown the suitability of the gelcast generated LSM cathodes for SOFC applications. (author)

Fluoro-apatite surface composition in aqueous solution deduced from potentiometric, electrokinetic, and solubility measurements, and spectroscopic observations

International Nuclear Information System (INIS)

Chairat, C.; Oelkers, E.H.; Schott, J.; Lartigue, J.E.

2007-01-01

The surface chemistry of fluoro-apatite in aqueous solution was investigated using electrokinetic techniques, potentiometric titrations, solubility measurements, and attenuated total reflection infrared spectroscopy. All methods indicate the formation of Ca/F depleted, P enriched altered layer via exchange reactions between H + and Ca 2+ , and OH - and F - at the fluoro-apatite (FAP) surface. Observations suggest that this leached layer has a di-calcium phosphate (CaHPO 4 ) composition and that it controls the apparent solubility of FAP. Electrokinetic measurements yield an iso-electric point value of 1 ± 0.5 consistent with a negatively charged FAP surface at pH ≥ 1. In contrast, surface titrations give an apparent pH of point of zero charge of similar to 7.7, consistent with a positively charged surface at pH ≤ 7.7. These differences are shown to stem from proton consumption by both proton exchange and dissolution reactions at the FAP surface. After taking account for these effects, FAP surface charge is shown to be negative to at least pH 4 by surface titration analysis. (authors)

Influence of single and binary doping of strontium and lithium on in vivo biological properties of bioactive glass scaffolds

Science.gov (United States)

Khan, Pintu Kumar; Mahato, Arnab; Kundu, Biswanath; Nandi, Samit K.; Mukherjee, Prasenjit; Datta, Someswar; Sarkar, Soumya; Mukherjee, Jayanta; Nath, Shalini; Balla, Vamsi K.; Mandal, Chitra

2016-01-01

Effects of strontium and lithium ion doping on the biological properties of bioactive glass (BAG) porous scaffolds have been checked in vitro and in vivo. BAG scaffolds were prepared by conventional glass melting route and subsequently, scaffolds were produced by evaporation of fugitive pore formers. After thorough physico-chemical and in vitro cell characterization, scaffolds were used for pre-clinical study. Soft and hard tissue formation in a rabbit femoral defect model after 2 and 4 months, were assessed using different tools. Histological observations showed excellent osseous tissue formation in Sr and Li + Sr scaffolds and moderate bone regeneration in Li scaffolds. Fluorochrome labeling studies showed wide regions of new bone formation in Sr and Li + Sr doped samples as compared to Li doped samples. SEM revealed abundant collagenous network and minimal or no interfacial gap between bone and implant in Sr and Li + Sr doped samples compared to Li doped samples. Micro CT of Li + Sr samples showed highest degree of peripheral cancellous tissue formation on periphery and cortical tissues inside implanted samples and vascularity among four compositions. Our findings suggest that addition of Sr and/or Li alters physico-chemical properties of BAG and promotes early stage in vivo osseointegration and bone remodeling that may offer new insight in bone tissue engineering. PMID:27604654

Remarkable Strontium B-Site Occupancy in FerroelectricPb(Zr1-xTix)O3 Solid Solutions Doped with Cryolite-Type StrontiumNiobate

Energy Technology Data Exchange (ETDEWEB)

Feltz, A.; Schmidt-Winkel, P.; Schossman, M.; Booth, C.H.; Albering, J.

2007-04-26

New high-performance ferroelectric materials based on Pb(Zr{sub 1-x}Ti{sub x})O{sub 3} (PZT) that are doped with cryolite-type strontium niobate (SNO, Sr{sub 4}(Sr{sub 2-2y/3}Nb{sub 2+2y/3})O{sub 11+y}V{sub 0,1-y} with 0 {le} y {le} 1), hence denoted PZT:SNO, and their microscopic structure are described. The combination of exceptional piezoelectric properties, i.e. a piezoelectric strain constant of d{sub 33} {approx} 760 pm/V, with excellent stability and degradation resistance makes ferroelectric PZT:SNO solid solutions very attractive for use in novel and innovative piezoelectric actuator and transducer applications. Extended X-ray absorption fine-structure (EXAFS) analyses of PZT:SNO samples revealed that {approx}10 % of the Sr cations occupy the nominal B-sites of the perovskite-type PZT host lattice. This result was supported by EXAFS analyses of both a canonical SrTiO{sub 3} perovskite and two SNO model and reference compounds. Fit models that do not account for Sr cations on B-sites were ruled out. A clear Sr-Pb peak in Fourier transformed EXAFS data visually confirmed this structural model. The generation of temporary oxygen vacancies and the intricate defect chemistry induced by SNO-doping of PZT are crucial for the exceptional materials properties exhibited by PZT:SNO materials.

Strontium-doped hematite as a possible humidity sensing material for soil water content determination.

Science.gov (United States)

Tulliani, Jean-Marc; Baroni, Chiara; Zavattaro, Laura; Grignani, Carlo

2013-09-10

The aim of this work is to study the sensing behavior of Sr-doped hematite for soil water content measurement. The material was prepared by solid state reaction from commercial hematite and strontium carbonate heat treated at 900 °C. X-Ray diffraction, scanning electron microscopy and mercury intrusion porosimetry were used for microstructural characterization of the synthesized powder. Sensors were then prepared by uniaxially pressing and by screen-printing, on an alumina substrate, the prepared powder and subsequent firing in the 800-1,000 °C range. These sensors were first tested in a laboratory apparatus under humid air and then in an homogenized soil and finally in field. The results evidenced that the screen printed film was able to give a response for a soil matric potential from about 570 kPa, that is to say well below the wilting point in the used soil.

Strontium-Doped Hematite as a Possible Humidity Sensing Material for Soil Water Content Determination

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Carlo Grignani

2013-09-01

Full Text Available The aim of this work is to study the sensing behavior of Sr-doped hematite for soil water content measurement. The material was prepared by solid state reaction from commercial hematite and strontium carbonate heat treated at 900 °C. X-Ray diffraction, scanning electron microscopy and mercury intrusion porosimetry were used for microstructural characterization of the synthesized powder. Sensors were then prepared by uniaxially pressing and by screen-printing, on an alumina substrate, the prepared powder and subsequent firing in the 800–1,000 °C range. These sensors were first tested in a laboratory apparatus under humid air and then in an homogenized soil and finally in field. The results evidenced that the screen printed film was able to give a response for a soil matric potential from about 570 kPa, that is to say well below the wilting point in the used soil.

Enhanced magnetic separation and photocatalytic activity of nitrogen doped titania photocatalyst supported on strontium ferrite.

Science.gov (United States)

Abd Aziz, Azrina; Yong, Kok Soon; Ibrahim, Shaliza; Pichiah, Saravanan

2012-01-15

An enhanced ferromagnetic property, visible light active TiO(2) photocatalyst was successfully synthesized by supporting strontium ferrite (SrFe(12)O(19)) onto TiO(2) doped with nitrogen (N) and compared with N-doped TiO(2). The synthesized catalysts were further characterized with X-ray diffraction (XRD), transmission electron microscope (TEM), energy dispersive X-ray spectroscopy (EDS), BET surface area analysis, vibrating sample magnetometer (VSM), X-ray photon spectroscopy (XPS) and visible light spectroscopy analysis for their respective properties. The XRD and EDS revealed the structural and inorganic composition of N-TiO(2) supported on SrFe(12)O(19). The supported N-TiO(2) exhibited a strong ferromagnetic property with tremendous stability against magnetic property losses. It also resulted in reduced band gap (2.8 eV) and better visible light absorption between 400 and 800 nm compared to N-doped TiO(2). The photocatalytic activity was investigated with a recalcitrant phenolic compound namely 2,4-dichlorophenol (2,4-DCP) as a model pollutant under direct bright and diffuse sunlight exposure. A complete degradation of 2,4-DCP was achieved with an initial concentration of 50mg/L for both photocatalysts in 180 min and 270 min respectively under bright sunlight. Similarly the diffuse sunlight study resulted in complete degradation for supported N-TiO(2) and >85% degradation N-TiO(2), respectively. Finally the supported photocatalyst was separated under permanent magnetic field with a mass recovery ≈ 98% for further reuse. Copyright © 2011 Elsevier B.V. All rights reserved.

Scandium doped Strontium Titanate Ceramics: Structure, Microstructure, and Dielectric Properties

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Tkach, Alexander

2008-08-01

Full Text Available Sc-doped strontium titanate (ST ceramics were synthesised by solid state reaction, according to the composition Sr_1-1.5xSc_xTiO₃ with x = 0-0.01. Structural properties and microstructure development was examined by XRD and SEM. The dielectric properties were evaluated as a function of the temperature and frequency in the radio frequency range. Lattice parameter, density and grain size, were found to decrease slightly with increasing Sc content. The dielectric permittivity and losses decrease also. Sc-doping has only a weak effect on the quantum paraelectric behaviour of ST and no dielectric anomaly was observed, what is probably related to the limited solubility of Sc on the Sr site of the perovskite lattice of ST.

Se sintetizaron materiales cerámicos de titanato de estroncio dopado con escandio mediante reacción en estado sólido De acuerdo a la composición Sr_1-1.5xSc_xTiO₃ con x= 0-0.1. Las propiedades estructurales y el desarrollo microestructural se estudiaron mediante XRD y SEM. La propiedades dieléctricas se estudiaron como función de la temperatura y de la frecuencia en el rango de la frecuencias de radio. Se observó que los parámetros de red, la densidad y el tamaño del grano disminuyen ligeramente con el contenido en Sc. La permitividad dieléctrica y las perdidas también disminuyen. El dopado con Sc tiene un efecto muy ligero sobre el comportamiento paraeléctrico cuántico del titanato de estroncio y no se observó anomalías dioeléctricas , lo que está probablemente relacionado con la baja solubilidad del Sc en posiciones del Sr en la estructura tipo perovskita del titanato de estroncio.

Characterization and Mineralization of Strontium Doped Nano Hydroxyapatite Coating on Titanium Rods

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Chuang WANG

2017-08-01

Full Text Available Pure nano hydroxyapatite (nHA and strontium doped nano hydroxyapatite (Sr-nHA, Sr/(Ca+Sr =10% were prepared by a one-step method which mainly used the principle of homogeneous phase co-precipitation. Fourier transform infrared spectroscopy (FT-IR revealed that the intensity of absorption was decreased with Sr doping. X-ray diffraction (XRD showed that special peak position of Sr-nHA shifted to a smaller 2θ angle compared with the pure nHA. Both the pure nHA (39.46±11.19nm in length and 15.90±3.65 nm in width and Sr-nHA (32.95±10.21 nm in length and 13.18±3.18 nm in width samples showed a tiny nano-rod feature. Moreover, Tc4 (Ti-6Al-4V rods (1 mm in diameter and 20 mm in length coated with pure nHA or Sr-nHA were prepared by high-energy plasma spraying. Elements of calcium (Ca, phosphorus (P, oxygen (O and Sr were detected on the Sr-nHA coating surface by Energy Dispersive Spectrometry (EDS. XRD result also indicates the chemical composition almost did not change significantly after spraying. By immersion in the simulated body fluid (SBF, in vitro mineralization ability was estimated and the superficial coats were evaluated by scanning electron microscopy (SEM and XRD. The results showed that Sr-nHA spraying surface has a better mineralization ability than the pure nHA coating. Therefore, the synthesized Sr-nHA would have potential for biological prostheses and other implantable materials.DOI: http://dx.doi.org/10.5755/j01.ms.23.3.17254

Study of thin films of carrier-doped strontium titanate with emphasis on their interfaces with organic thin films

Energy Technology Data Exchange (ETDEWEB)

Sato, Naoki [Laboratory of Molecular Aggregation Analysis, Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011 (Japan)]. E-mail: naokis@e.kuicr.kyoto-u.ac.jp; Harada, Youichiro [Laboratory of Molecular Aggregation Analysis, Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011 (Japan); Terashima, Takahito [International Research Center of Elements Science, Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011 (Japan); Kanda, Ryoko [International Research Center of Elements Science, Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011 (Japan); Takano, Mikio [International Research Center of Elements Science, Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011 (Japan)

2005-05-15

Fifty nanometer-thick metal-doped strontium titanate (M:STO, M = La and V) films deposited epitaxially on single crystalline STO substrates were characterized in comparison with indium tin oxide (ITO) covered glasses, to check their applicability to optically transparent anode materials for organic optoelectronic devices. M:STO, in particular V:STO, films turned out to have distinct surface flatness, needfully low electric resistivities and notably large work functions. While their optical transmittances are lower than those of ITOs at this moment, we suggest that M:STO films have a potential to take the place of ITO films. Further, we have observed energy level alignments for copper phthalocyanine thin films at the interface of V:STO.

Synthesis and characterization of Ho{sup 3+}-doped strontium titanate downconversion nanocrystals and its application in dye-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Li, Y.Y. [Department of Inorganic Nonmetallic Materials Engineering, Dalian Polytechnic University, Dalian 116034 (China); Liaoning Provincial College Key Laboratory of New Materials and Material Modification, Dalian Polytechnic University, Dalian 116034 (China); Hao, H.S., E-mail: beike1952@163.com [Department of Inorganic Nonmetallic Materials Engineering, Dalian Polytechnic University, Dalian 116034 (China); Liaoning Provincial College Key Laboratory of New Materials and Material Modification, Dalian Polytechnic University, Dalian 116034 (China); Qin, L. [National Engineering Research Center of Seafood, Dalian Polytechnic University, Dalian 116034 (China); Wang, H.L.; Nie, M.Q.; Hu, Z.Q.; Gao, W.Y.; Liu, G.S. [Department of Inorganic Nonmetallic Materials Engineering, Dalian Polytechnic University, Dalian 116034 (China); Liaoning Provincial College Key Laboratory of New Materials and Material Modification, Dalian Polytechnic University, Dalian 116034 (China)

2015-02-15

Highlights: • A new downconversion (DC) nanocrystal (SrTiO{sub 3}:Ho{sup 3+}) was synthesized. • The effect of SrTiO{sub 3}:Ho{sup 3+} as a photoanode in DSSCs was investigated. • SrTiO{sub 3}:Ho{sup 3+} absorb ultraviolet light and downconvert it to visible light. • DC SrTiO{sub 3}:Ho{sup 3+} as a photoanode achieve the higher photoelectric conversion efficiency. - Abstract: Ho{sup 3+}-doped strontium titanate (SrTiO{sub 3}:Ho{sup 3+}) downconversion (DC) nanocrystals are synthesized by the solid state interaction of titanium dioxide, strontium nitrate, holmium oxide and sodium chloride and then used as a photoanode in dye-sensitized solar cells (DSSCs) to investigate the effect of DC nanocrystals in DSSCs. Differential thermal analysis, X-ray diffraction, scanning electronic microscope, energy dispersive spectroscopy and Brunauer-Emmet-Teller analysis confirmed the formation of cubic structured SrTiO{sub 3}:Ho{sup 3+} nanocrystals with diameters of 40-400 nm, pore size of ∼45 nm, sintering temperature of 950 °C. The photofluorescence and UV-Vis absorption spectra of the SrTiO{sub 3}:Ho{sup 3+} nanocrystals revealed strong emission intensity and visible light absorption when doped content of holmium oxide was between 1 wt% and 3 wt%. Compared with the pure SrTiO{sub 3} photoanode, SrTiO{sub 3}:Ho{sup 3+} DC photoanode showed a greater photovoltaic efficiency. The photoelectric conversion efficiency (η) of the DSSCs with a SrTiO{sub 3}:Ho{sup 3+} photoanode doped with 1 wt% holmium oxide was 59% higher than that with a pure SrTiO{sub 3} photoanode. This phenomenon could be explained by SrTiO{sub 3}:Ho{sup 3+} nanocrystals’ ability to absorb ultraviolet light and downconvert it to visible light, which extends spectral response range of DSSC to the ultraviolet region and increased the short-circuit current density (Jsc) of DSSCs.

Strontium doped poly-ε-caprolactone composite scaffolds made by reactive foaming

Energy Technology Data Exchange (ETDEWEB)

Zehbe, Rolf, E-mail: zehbe@bls-germany.com [BLS Laboratories GmbH, Berlin (Germany); University of Potsdam, Institute of Physics and Astronomy, Potsdam (Germany); Zehbe, Kerstin [University of Potsdam, Department of Chemistry, Potsdam (Germany)

2016-10-01

In the reconstruction and regeneration of bone tissue, a primary goal is to initiate bone growth and to stabilize the surrounding bone. In this regard, a potentially useful component in biomaterials for bone tissue engineering is strontium, which acts as cationic active agent, triggering certain intracellular pathways and acting as so called dual action bone agent which inhibits bone resorption while stimulating bone regeneration. In this study we established a novel processing for the foaming of a polymer (poly-ε-caprolactone) and simultaneous chemical reaction of a mixture of calcium and strontium hydroxides to the respective carbonates using supercritical carbon dioxide. The resultant porous composite scaffold was optimized in composition and strontium content and was characterized via different spectroscopic (infrared and Raman spectroscopy, energy dispersive X-ray spectroscopy), imaging (SEM, μCT), mechanical testing and in vitro methods (fluorescence vital staining, MTT-assay). As a result, the composite scaffold showed good in vitro biocompatibility with partly open pore structure and the expected chemistry. First mechanical testing results indicate sufficient mechanical stability to support future in vivo applications. - Highlights: • Reactive foaming has been established for the synthesis of a PCL matrix with integrated strontium and calcium species • This material can potentially be useful in bone tissue engineering applications • Comparative in vitro cell culture experiments, imaging and spectroscopy analysis have been conducted.

Synthesis and characterization of strontium molybdate doped with copper, cobalt and zinc for purposes photocatalytic

International Nuclear Information System (INIS)

Dutra, F.B.; Silva, M.M.S.; Moriyama, A.L.L.; Souza, C.P.

2016-01-01

The broad concerns of contemporary society with environmental problems requires legislation and more effective techniques for wastewater treatment. In recent years, ceramic materials that have properties such as high melting points and high stability have been receiving great emphasis in several studies in particular heterogeneous photocatalysis, rapid and efficient method for the complete mineralization of contaminants. In this context, the present work deals with the synthesis and characterization of molybdate Strontium (SrMoO4) doped with copper, cobalt and zinc for the purpose of photocatalytic studies. The compounds were synthesized by complexation method EDTA / Citrate basic medium. The powders were characterized by Thermogravimetric Analysis (TG), X-Ray Diffraction (XRD), Particle size distribution by laser diffraction, Spectroscopy in the UV-Visible region, Energy Dispersive Spectroscopy (EDS) and Scanning Electron Microscopy (SEM), showing promising results as the crystalline phase of development and potential uses for the purpose of heterogeneous photocatalysis. (author)

Improvement in crystallization and electrical properties of barium strontium titanate thin films by gold doping using metal-organic deposition method

International Nuclear Information System (INIS)

Wang, H.-W.; Nien, S.-W.; Lee, K.-C.; Wu, M.-C.

2005-01-01

The effect of gold (Au) on the crystallization, dielectric constant and leakage current density of barium strontium titanate (BST) thin films was investigated. BST thin films with various gold concentrations were prepared via a metal-organic deposition process. The X-ray diffraction shows enhanced crystallization as well as expanded lattice constants for the gold-doped BST films. Thermal analysis reveals that the gold dopant induces more complete decomposition of precursor for the doped films than those of undoped ones. The leakage current density of BST films is greatly reduced by the gold dopant over a range of biases (1-5 V). The distribution of gold was confirmed by electron energy loss spectroscopy and found to be inside the BST grains, not in the grain-boundaries. Gold acted as a catalyst, inducing the nucleation of crystallites and improving the crystallinity of the structure. Its addition is shown to be associated to the improvement of the electrical properties of BST films

Barium iodide and strontium iodide crystals andd scintillators implementing the same

Science.gov (United States)

Payne, Stephen A; Cherepy, Nerine J; Hull, Giulia E; Drobshoff, Alexander D; Burger, Arnold

2013-11-12

In one embodiment, a material comprises a crystal comprising strontium iodide providing at least 50,000 photons per MeV. A scintillator radiation detector according to another embodiment includes a scintillator optic comprising europium-doped strontium iodide providing at least 50,000 photons per MeV. A scintillator radiation detector in yet another embodiment includes a scintillator optic comprising SrI.sub.2 and BaI.sub.2, wherein a ratio of SrI.sub.2 to BaI.sub.2 is in a range of between 0:1 A method for manufacturing a crystal suitable for use in a scintillator includes mixing strontium iodide-containing crystals with a source of Eu.sup.2+, heating the mixture above a melting point of the strontium iodide-containing crystals, and cooling the heated mixture near the seed crystal for growing a crystal. Additional materials, systems, and methods are presented.

Synthesis, processing and characterization of the solid oxide half-cells cathode/electrolyte of strontium-doped lanthanum manganite/Yttria-stabilized zirconia

International Nuclear Information System (INIS)

Chiba, Rubens

2010-01-01

The ceramic films of strontium-doped lanthanum manganite (LSM) and strontium doped lanthanum manganite/Yttria-stabilized zirconia (LSM/YSZ) are used as cathodes of the high temperature solid oxide fuel cells (HTSOFC). These porous ceramic films had been deposited on the YSZ dense ceramic substrate, used as electrolyte, structural component of the module, thus conferring a configuration of half-cell called auto-support. The study of the half-cell it is basic, therefore in the interface cathode/electrolyte occurs the oxygen reduction reaction, consequently influencing in the performance of the HTSOFC. In this direction, the present work contributes for the processing of thin films, using the wet powder spraying technique, adopted for the conformation of the ceramic films for allowing the attainment of porous layers with thicknesses varied in the order of micrometers. The LSM powders were synthesized by the citrate technique and the LSM/YSZ powders synthesized by the solid mixture technique. In the stage of formation were prepared organic suspensions of LSM and LSM/YSZ fed by gravity in a manual aerograph. For the formation of the YSZ substrate was used a hydraulic uniaxial press. The attainment of solid oxide half-cells cathode/electrolyte was possible of crystalline structures hexagonal for phase LSM and cubic for phase YSZ. The half-cells micrographs show that the YSZ substrate is dense, enough to be used as solid electrolyte, and the LSM and LSM/YSZ films are presented porous with approximately 30 μm of thickness and good adherence between the cathodes and the electrolyte. The presence of composite cathode between the LSM cathode and YSZ substrate, presented an increase in the electrochemical performance in the oxygen reduction reaction. (author)

Low-temperature sintering and electrical properties of strontium- and magnesium-doped lanthanum gallate with V2O5 additive

Science.gov (United States)

Ha, Sang Bu; Cho, Yoon Ho; Ji, Ho-Il; Lee, Jong-Ho; Kang, Yun Chan; Lee, Jong-Heun

2011-03-01

The effects of a V2O5 additive on the low-temperature sintering and ionic conductivity of strontium- and magnesium-doped lanthanum gallate (LSGM: La0.8Sr0.2Ga0.8Mg0.2O2.8) are studied. The LSGM powders prepared by the glycine nitrate method are mixed with 0.5-2 at.% of VO5/2 and then sintered at 1100-1400 °C in air for 4 h. The apparent density and phase purity of the LSGM specimens are increased with increasing sintering temperature and VO5/2 concentration due to the enhanced sintering and mass transfer via the intergranular liquid phase. The 1 at.% VO5/2-doped LSGM specimen sintered at 1300 °C exhibits a high oxide ion conductivity of ∼0.027 S cm-1 at 700 °C over a wide range of oxygen partial pressure (PO2 =10-27 - 1 atm), thereby demonstrating its potential as a useful electrolyte for anode-supported solid oxide fuel cells (SOFCs) without the requirement for any buffer layer between the electrolyte and anode.

Lanthanum-doped mesostructured strontium titanates synthesized via sol–gel combustion route using citric acid as complexing agent

Energy Technology Data Exchange (ETDEWEB)

Sukpanish, Polthep [Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok 10330 (Thailand); Center of Excellence on Petrochemical and Materials Technology (PETROMAT), Chulalongkorn University, Patumwan, Bangkok 10330 (Thailand); Lertpanyapornchai, Boontawee [Program in Petrochemistry, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok 10330 (Thailand); Yokoi, Toshiyuki [Division of Catalytic Chemistry, Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 (Japan); Ngamcharussrivichai, Chawalit, E-mail: Chawalit.Ng@chula.ac.th [Department of Chemical Technology, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok 10330 (Thailand); Center of Excellence on Petrochemical and Materials Technology (PETROMAT), Chulalongkorn University, Patumwan, Bangkok 10330 (Thailand)

2016-09-15

In the present work, a series of lanthanum-doped mesostructured strontium titanate (LMST) materials with different La/Sr ratios were synthesized via a sol–gel combustion method in the presence of citric acid as a complexing agent and Pluronic P123 as a templating agent. The effects of the amount of doped La and calcination temperature on the physicochemical properties of the LMSTs were examined using various techniques. Powder X-ray diffraction confirmed the substitution of La{sup 3+} into the SrTiO{sub 3} lattice, generating cubic perovskite La{sub x}Sr{sub 1−x}TiO{sub 3}, for the LMST materials calcined at 600 °C. The purity and crystallinity of the desired perovskite phase were enhanced by citric acid addition. The solubility limit of La{sup 3+} substitution at an La/Sr ratio of 0.43 was determined by structural and morphological studies. Increasing the La doping amount decreased the crystallinity and compositional homogeneity, because an La-rich amorphous phase segregated on the surface, but improved the mesoporosity. N{sub 2} physisorption measurements indicated that the LMSTs had a bimodal pore size distribution, of which the larger one was characterized by the crystallite size of mixed oxides, and the specific surface area of 24.9–37.3 m{sup 2} g{sup −1}. The formation of mesopores in the LMST materials synthesized via sol–gel combustion was explained based on a combination of soft- and hard-templating chemistries. - Highlights: • La-doped mesoporous SrTiO{sub 3} (LMST) was prepared first time via sol-gel combustion. • Pluronic P123 triblock copolymer was used as a cheap templating agent. • Citric acid as a complexing agent enhanced the purity and crystallinity of SrTiO{sub 3}. • The textural properties of LMST were improved by increasing the La doping amount. • Mesopore formation was explained by a combined soft- and hard-templating route.

Application of the Rietveld method in powders of strontium-doped lanthanum manganite calcined in different temperatures

International Nuclear Information System (INIS)

Chiba, R.; Vargas, R.A.; Martinez, L.G.; Andreoli, M.; Seo, E.S.M.

2010-01-01

The strontium-doped lanthanum manganite (LSM) is a ceramic material used as cathode in device called High Temperature Solid Oxide Fuel Cell. In this work, the LSM was synthesized by the citrate technique with the objective to get powders without the formation of secondary phases, such as lanthanum oxide and the lanthanum hydroxide, harmful for the functional performance of the device. The definitive calcination temperatures had been 700, 900 and 1100 deg C, due the decomposition of the polymeric precursors to present stabilization from 480 deg C. The analysis by X-ray diffraction of the calcined powders in different temperatures shows the formation only of phase LSM of hexagonal crystalline structure, type pseudo-perovskite. Using the refinement of Rietveld was determined the parameters and volumes of unity cells, atomic positions and occupations. These results confirm that the chemical compositions obtained are similar to the nominal. (author)

Crystal growth and characterization of europium doped lithium strontium iodide scintillator as an ionizing radiation detector

Science.gov (United States)

Uba, Samuel

High performance detectors used in the detection of ionizing radiation is critical to nuclear nonproliferation applications and other radiation detectors applications. In this research we grew and tested Europium doped Lithium Strontium Iodide compound. A mixture of lithium iodide, strontium iodide and europium iodide was used as the starting materials for this research. Congruent melting and freezing temperature of the synthesized compound was determined by differential scanning calorimetry (DSC) using a Setaram Labsys Evo DSC-DTA instrument. The melting temperatures were recorded at 390.35°C, 407.59°C and freezing temperature was recorded at 322.84°C from a graph of heat flow plotted against temperature. The synthesized material was used as the charge for the vertical Bridgeman growth, and a 6.5 cm and 7.7cm length boule were grown in a multi-zone transparent Mullen furnace. A scintillating detector of thickness 2.53mm was fabricated by mechanical lapping in mineral oil, and scintillating response and timing were obtained to a cesium source using CS-137 isotope. An energy resolution (FWHM over peak position) of 12.1% was observed for the 662keV full absorption peak. Optical absorption in the UV-Vis wavelength range was recorded for the grown crystal using a U-2900 UV/VIS Spectrophotometer. Absorption peaks were recorded at 194nm, 273nm, and 344nm from the absorbance spectrum, various optical parameters such as absorption coefficient, extinction coefficient, refractive index, and optical loss were derived. The optical band gap energy was calculated using Tauc relation expression at 1.79eV.

Spin injection and detection in lanthanum- and niobium-doped SrTiO3 using the Hanle technique

KAUST Repository

Han, Wei

2013-07-08

There has been much interest in the injection and detection of spin-polarized carriers in semiconductors for the purposes of developing novel spintronic devices. Here we report the electrical injection and detection of spin-polarized carriers into Nb-doped strontium titanate single crystals and La-doped strontium titanate epitaxial thin films using MgO tunnel barriers and the three-terminal Hanle technique. Spin lifetimes of up to ∼100 ps are measured at room temperature and vary little as the temperature is decreased to low temperatures. However, the mobility of the strontium titanate has a strong temperature dependence. This behaviour and the carrier doping dependence of the spin lifetime suggest that the spin lifetime is limited by spin-dependent scattering at the MgO/strontium titanate interfaces, perhaps related to the formation of doping induced Ti 3+. Our results reveal a severe limitation of the three-terminal Hanle technique for measuring spin lifetimes within the interior of the subject material. © 2013 Macmillan Publishers Limited. All rights reserved.

Synthesis and characterization of calcium hydroxy and fluoroapatite functionalized with methyl phosphonic dichloride

Energy Technology Data Exchange (ETDEWEB)

Agougui, Hassen; Aissa, Abdallah [Laboratoire de Physico-Chimie des Materiaux, Faculte des Sciences de Monastir, 5019 Monastir (Tunisia); Debbabi, Mongi, E-mail: m.debbabi@yahoo.fr [Laboratoire de Physico-Chimie des Materiaux, Faculte des Sciences de Monastir, 5019 Monastir (Tunisia)

2012-11-15

Highlights: Black-Right-Pointing-Pointer Surface reactivity of apatites toward methyl phosphonic dichloride is tested. Black-Right-Pointing-Pointer Chemical analysis shows that hydroxyapatite is more reactive. Black-Right-Pointing-Pointer NMR spectra show the formation of Ca-O-P{sub org} and P{sub inorg}-O-P{sub org} bonds. Black-Right-Pointing-Pointer AFM indicated that the texture surface was changed by grafting. - Abstract: The nature of apatite-organic molecule interaction was the subject of many investigations. Grafting the organic molecule onto the inorganic support may precede through either formation of covalent bonds or ionic interaction between superficial hydroxyl on the apatite surface and organic functions. The hybrid materials obtained by functionalization of apatite surfaces with phosphonate moieties are of interest for their potential applications such in catalysis, chromatography and biomedical domain. In this scope, calcium hydroxyl and fluoroapatite (CaHAp and CaFAp) were prepared in the presence of the methyl phosphonic dichloride (MPO), by contact method in organic solvent at 25 Degree-Sign C for 2 days. The products are rigorously characterized by chemical analysis, infrared (IR), MAS-NMR spectroscopies, powder X-ray diffraction (XRD), atomic force microscopy (AFM) and specific surface area (SSA). The X-ray powder analysis showed that the crystallinity was sensibly affected by the presence of organic moieties. The IR spectroscopy showed new vibration modes appearing related to phosphonate groups essentially at 2930, 1315, 945, 764 and 514 cm{sup -1}. The {sup 31}P MAS NMR spectrum for hydroxy and fluoroapatite exhibits a single signal at 2.8 ppm. After reaction with (MPO) the spectra show the presence of new signals, assigned to the formation of organic-inorganic bond between the superficial hydroxyl groups of the apatite ({identical_to}CaOH) and ({identical_to}POH) and methyl phosphonic dichloride. The SSA decreases with increasing

Electronic and magnetic properties of 3d transition metal-doped strontium clusters: Prospective magnetic superatoms

International Nuclear Information System (INIS)

Chauhan, Vikas; Sen, Prasenjit

2013-01-01

Highlights: • Structural, electronic and magnetic properties of TM-Sr clusters are studied using DFT methods. • CrSr 9 and MnSr 10 have enhanced stability in the CrSr n and MnSrn series. • These two clusters behave as magnetic superatoms. • A qualitative understanding of the magnetic coupling between two superatom units is offered. • Reactivity of these superatoms to molecular oxygen also studied. - Abstract: Structural, electronic and magnetic properties of 3d transition metal doped strontium clusters are studied using first-principles electronic structure methods based on density functional theory. Clusters with enhanced kinetic and thermodynamic stability are identified by studying their hardness, second order energy difference and adiabatic spin excitation energy. CrSr 9 and MnSr 10 are found to have enhanced stability. They retain their structural identities in assemblies, and are classified as magnetic superatoms. A qualitative understanding of the magnetic coupling between two cluster units is arrived at. Reactivity of these superatoms with O 2 molecule is also studied. Prospects for using these magnetic superatoms in applications are discussed

Mechanoluminescence of Dy doped strontium aluminate nanophosphors

Energy Technology Data Exchange (ETDEWEB)

Sharma, Ravi, E-mail: rvsharma65@gmail.com [Department of Physics, Govt. Arts and Commerce Girls College, Raipur, C.G. 492001 (India); Bisen, D.P. [School of Studies in Physics and Astrophysics, Pt. Ravishankar Shukla University, Raipur, C.G. 492010 (India); Chandra, B.P. [Department of Postgraduate Studies and Research in Physics and Electronics, Rani Durgavati University, Jabalpur 482001 (India)

2015-12-15

Nanosized strontium aluminate phosphors activated with Dy{sup 3+} were prepared by a combustion method. Nanophosphor was prepared by this method at reaction temperatures as low as 600 °C. Powder X-ray diffraction (XRD), scanning electron microscope analysis was used to characterize the prepared product. The monoclinic phase was observed in the XRD pattern. The particle size of the samples was calculated around 35 nm. The SEM images show irregular shape of the prepared nanophosphor. Two peaks were found in the mechanoluminescence (ML) response curve plotted between time and ML intensity. The H{sub 3}BO{sub 3} added strontium aluminate phosphors activated with Dy show more bright ML peak as compared to the powders of SrAl{sub 2}O{sub 4}:Dy{sup 3+} without H{sub 3}BO{sub 3.} It was found that the PL and ML intensity increases with increasing concentration of Dy, it becomes maximum for 3% of Dy. The photoluminescence emission shows two intense fluorescence transitions peaks at 498 nm and 583 nm, {sup 4}F{sub 9/2}→{sup 6}H{sub 15/2} in the blue and {sup 4}F{sub 9/2}→{sup 6}H{sub 13/2} in the yellow-orange wavelength region. - Highlights: • Combustion synthesis route is used to prepare the SrAl{sub 2}O{sub 4}: Dy {sup 3+} nanophosphors. • The size of the synthesized sample was found to be in the nano-meter range. • The mechanoluminescence of SrAl{sub 2}O{sub 4}:Dy {sup 3+} nanophosphors is studied. • The photoluminescence of SrAl{sub 2}O{sub 4}: Dy {sup 3+} nanophosphors showed blue-shift as compared to bulk. • Effect of H{sub 3}BO{sub 3} on the mechanoluminescence of SrAl{sub 2}O{sub 4}:Dy{sup 3+} was studied.

Optical properties of Er{sup 3+}-doped strontium barium niobate nanocrystals obtained by thermal treatment in glass

Energy Technology Data Exchange (ETDEWEB)

Haro-Gonzalez, P. [Dep. of Fisica Fundamental Experimental, Electronica y Sistemas, Universidad de La Laguna Avda Astrofisico Franscisco Sanchez, 38206 La Laguna, S/C de Tenerife (Spain)], E-mail: patharo@ull.es; Lahoz, F. [Dep. of Fisica Fundamental Experimental, Electronica y Sistemas, Universidad de La Laguna Avda Astrofisico Franscisco Sanchez, 38206 La Laguna, S/C de Tenerife (Spain); Gonzalez-Platas, J. [Dep. of Fisica Fundamental II, Universidad de La Laguna, 38206 La Laguna, S/C de Tenerife (Spain); Caceres, J.M. [Dep. of Edafologia y Geologia, Universidad de La Laguna, 38206 La Laguna, S/C de Tenerife (Spain); Gonzalez-Perez, S. [Dep. of Fisica Fundamental Experimental, Electronica y Sistemas, Universidad de La Laguna Avda Astrofisico Franscisco Sanchez, 38206 La Laguna, S/C de Tenerife (Spain); Marrero-Lopez, D. [Dep. of Quimica Inorganica, Universidad de La Laguna, 38206 La Laguna, S/C de Tenerife (Spain); Capuj, N. [Dep. of Fisica Basica, Universidad de La Laguna, 38206 La Laguna, S/C de Tenerife (Spain); Martin, I.R. [Dep. of Fisica Fundamental Experimental, Electronica y Sistemas, Universidad de La Laguna Avda Astrofisico Franscisco Sanchez, 38206 La Laguna, S/C de Tenerife (Spain)

2008-05-15

Measurements of the optical properties of Er{sup 3+} ions in strontium barium niobate glass and glass ceramics have been carried out. The glasses have been fabricated using a melt-quenching method, and the glass ceramic samples have been obtained from the glass precursor by a thermal treatment. The ceramic samples formed by a glassy phase, and a crystalline phase contains nanocrystals of Sr{sub 1-x}Ba{sub x}Nb{sub 2}O{sub 6} (SBN) doped with Er{sup 3+} ions with a mean size of {approx}50 nm, as confirmed with XRD. Green up-conversion emission has been obtained under excitation at 800 nm, and the temporal evolution of this emission has been reported with the purpose of determining the involved up-conversion mechanism. These optical measures have confirmed that the Er{sup 3+} ions have been incorporated into the SBN matrix, after a thermal treatment, which produced an increment of the up-conversion efficiency.

Fabrication of Lanthanum Strontium Cobalt Ferrite-Gadolinium-Doped Ceria Composite Cathodes Using a Low-Price Inkjet Printer.

Science.gov (United States)

Han, Gwon Deok; Choi, Hyung Jong; Bae, Kiho; Choi, Hyeon Rak; Jang, Dong Young; Shim, Joon Hyung

2017-11-15

In this work, we have successfully fabricated lanthanum strontium cobalt ferrite (LSCF)-gadolinium-doped ceria (GDC) composite cathodes by inkjet printing and demonstrated their functioning in solid oxide fuel cells (SOFCs). The cathodes are printed using a low-cost HP inkjet printer, and the LSCF and GDC source inks are synthesized with fluidic properties optimum for inkjet printing. The composition and microstructure of the LSCF and GDC layers are successfully controlled by controlling the color level in the printed images and the number of printing cycles, respectively. Anode-support type SOFCs with optimized LSCF-GDC composite cathodes synthesized by our inkjet printing method have achieved a power output of over 570 mW cm -2 at 650 °C, which is comparable to the performance of a commercial SOFC stack. Electrochemical impedance analysis is carried out to establish a relationship between the cell performance and the compositional and structural characteristics of the printed LSCF-GDC composite cathodes.

Hydrogen Solubility in Pr-doped and Un-doped YSZ for One Chamber Fuel Cell

DEFF Research Database (Denmark)

Bay, Lasse; Horita, T.; Sakai, N.

1998-01-01

SIMS analysis. Doping of Pr in the YSZ resulted in a higher intensity of the D ion, which indicated that hydrogen solubility was raised by the doping. The solubility of hydrogen in the electrolyte may affect the performance of one chamber fuel cells. (C) 1998 Elsevier Science B.V. All rights reserved.......Yttria-stabilised zirconia electrolytes (YSZ and Pr-doped YSZ) and yttria-doped strontium cerate (SYC) were tested in a one chamber fuel cell fed with a mixture of methane and air at 1223 K. The obtained performances were 4 mW cm(-2), 3 mW cm(-2), 2.5 mW cm(-2), and 0.15 mW cm(-2) for SYC, 1.8 mol...

Influence of organic solvent treatment on elasticoluminescent property of europium-doped strontium aluminates

International Nuclear Information System (INIS)

Fujio, Yuki; Xu, Chao-Nan; Terasaki, Nao; Ueno, Naohiro

2014-01-01

The influence of an organic solvent treatment on elasticoluminescent (ELS) characteristics of mechanoluminescent (ML) sensor using the composite film consisting of an ELS material and epoxy resin was investigated. We used strontium aluminate doped with a small amount of europium (SrAl 2 O 4 :Eu, SAOE) as an ELS material in this study. After evaluating the ELS characteristics of the fabricated ML sensors using SAOE treated with/without various organic solvents, SAOE treated with methanol and ethanol showed lower ELS intensities than that of untreated SAOE. In contrast, the ELS response curves against strain for the ML sensors using SAOE treated with acetone and toluene, overlapped with that of untreated SAOE. From the characterization of SAOE treated with alcohols, such as methanol and ethanol, we can hypothesize that poor ELS characteristics is due to the degradation of the SAOE grain surfaces by the hydrolyze reaction of SAOE with hydroxyl group of alcohol. Thus, on the basis of the obtained results, we can conclude that the selection of organic solvent used in the preparation of SAOE film is of considerable importance in the development of ML sensor with a highly-reliable ELS characteristic. -- Highlights: • Influence of organic solution treatment on the sensing characteristics of a mechanoluminescent (ML) sensor using SrAl 2 O 4 :Eu has been investigated. • An alcohol treatment of SAOE powder has considerable effect on its ML characteristic. • There is almost no influence of acetone and toluene treatments on ML characteristics

STRONTIUM PRECIPITATION

Science.gov (United States)

McKenzie, T.R.

1960-09-13

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

An epitaxial transparent conducting perovskite oxide: double-doped SrTiO3

NARCIS (Netherlands)

Ravichandran, Jayakanth; Siemons, W.; Heijmerikx, Herman; Huijben, Mark; Majumdar, Arun; Ramesh, Ramamoorthy

2010-01-01

Epitaxial thin films of strontium titanate doped with different concentrations of lanthanum and oxygen vacancies were grown on LSAT substrates by pulsed laser deposition technique. Films grown with 5−15% La doping and a critical growth pressure of 1−10 mTorr showed high transparency (>70−95%) in the

Effects of focused ion beam milling on electron backscatter diffraction patterns in strontium titanate and stabilized zirconia

DEFF Research Database (Denmark)

Saowadee, Nath; Agersted, Karsten; Bowen, Jacob R.

2012-01-01

This study investigates the effect of focused ion beam (FIB) current and accelerating voltage on electron backscatter diffraction pattern quality of yttria‐stabilized zirconia (YSZ) and Nb‐doped strontium titanate (STN) to optimize data quality and acquisition time for 3D‐EBSD experiments by FIB...

Effect of multi-layered bottom electrodes on the orientation of strontium-doped lead zirconate titanate thin films

Energy Technology Data Exchange (ETDEWEB)

Bhaskaran, M. [Microelectronics and Materials Technology Centre, School of Electrical and Computer Engineering, RMIT University, GPO Box 2476V, Melbourne, Victoria 3001 (Australia)], E-mail: madhu.bhaskaran@gmail.com; Sriram, S. [Microelectronics and Materials Technology Centre, School of Electrical and Computer Engineering, RMIT University, GPO Box 2476V, Melbourne, Victoria 3001 (Australia); Mitchell, D.R.G.; Short, K.T. [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation (ANSTO), PMB 1, Menai, New South Wales 2234 (Australia); Holland, A.S. [Microelectronics and Materials Technology Centre, School of Electrical and Computer Engineering, RMIT University, GPO Box 2476V, Melbourne, Victoria 3001 (Australia)

2008-09-30

This article discusses the results from X-ray diffraction (XRD) analysis of piezoelectric strontium-doped lead zirconate titanate (PSZT) thin films deposited on multi-layer coatings on silicon. The films were deposited by RF magnetron sputtering on a metal coated substrate. The aim was to exploit the pronounced piezoelectric effect that is theoretically expected normal to the substrate. This work highlighted the influence that the bottom electrode architecture exerts on the final crystalline orientation of the deposited thin films. A number of bottom electrode architectures were used, with the uppermost metal layer on which PSZT was deposited being gold or platinum. The XRD analysis revealed that the unit cell of the PSZT thin films deposited on gold and on platinum were deformed, relative to expected unit cell dimensions. Experimental results have been used to estimate the unit cell parameters. The XRD results were then indexed based on these unit cell parameters. The choice and the thickness of the intermediate adhesion layers influenced the relative intensity, and in some cases, the presence of perovskite peaks. In some cases, undesirable reactions between the bottom electrode layers were observed, and layer architectures to overcome these reactions are also discussed.

Doped Tl-1212 and Tl-1223 superconductors

International Nuclear Information System (INIS)

Eder, M.H.

2001-09-01

This work describes the preparation and characterization of thallium-lead-strontium-barium-calcium-(uranium)-copperoxide (Tl-1212, Tl-1223) high-temperature superconductors. The precursors were prepared via nitrate method. After calcination the oxidic powders were mixed with stoichiometric amounts of an Tl 2 O 3 , PbO, Er 2 O 3 and Gd 2 O 3 by milling and afterwards uniaxial compressed. Sintering was carried out in silver foils. X-ray diffractometry and high-resolution microscopy in combination with scanning electron microscopy (including EDAX) were used to study the influence of varying thallium/lead-, strontium/barium-, calcium/rare earth element ratios and the effect of uranium on the phase composition and microstructure of bulk superconductors. Furthermore the influence of the composition on the electrical and magnetical properties was studied. On phase pure Tl-1212 and Tl-1223 superconductors NMR-measurements were done. Small amounts of gadolinium and erbium instead of calcium and excess-uranium have a positive impact on the electrical and magnetical properties of the Tl-1223 superconductors. Higher amounts of these doping elements favor the Tl-1212 phase. Tl-1212 superconductors with varying thallium/lead- strontium/barium- and calcium/gadolinium ratios were prepared phasepure in wide range of doping. Transition temperatures up to 96 K were achieved. It was shown that lead has an oxidation number of +4 and thallium of +3. (author)

Simulating the Transfer of Strontium-90 from Soil to Leafy Vegetables by Using Strontium-88.

Science.gov (United States)

Kuke, Ding; Shujuan, Liu; Yingxue, He; Dong, Yan; Fengshou, Zhang; Shuifeng, Wang; Jinghua, Guo; Wei, Zhang; Xin, Wang; Xiaoyan, Jiang

The transfer, from soil to Chinese cabbage and spinach, of radioactive strontium-90 released as a result of accidents in nuclear power stations was studied using a stable isotope of strontium, namely nuclide strontium-88 ( 88 Sr). The study led to an experimental model for assessing the hazard of radionuclide strontium-90 ( 90 Sr) entering the food chain and for predicting the risk to food safety. Chinese cabbage and spinach were grown in pots in a greenhouse and irrigated with deionized water containing known quantities of strontium. Based on the strontium content of that water, the plants were divided into five groups (treatments) and strontium content of the soil, and 30-day-old plants were determined by inductively coupled plasma atomic emission spectroscopy instrument (ICP-AES). Data on the strontium content of soil and plants enabled the development of a model using MATLAB, a mathematical software package, which included curve fitting and problem solving using regression equations and differential equations. Although strontium curves for leaves, stems, and roots of Chinese cabbage were not exactly the same, all showed a non-linear increase when compared with the increase in the content of strontium in soil. Strontium curves for leaves, stems, and roots of spinach were very similar and showed an initial increase followed by a decrease. Strontium concentrations in both Chinese cabbage and spinach were initially related to the concentrations of sodium and sulfur, the next two relevant nuclides being calcium and magnesium. The relationship between calcium and strontium in Chinese cabbage was different from that in spinach. By using 88 Sr to simulate the transfer of radionuclide 90 Sr from soil to a crop, the relevant data required to deal with accidental release of strontium can be obtained using a fitting curve and regression equations, thereby providing some experimental basis for evaluating the potential hazards posed by such accidents to the food chain.

Isotope exchange of strontium and molybdate ions in strontium polymolybdates

International Nuclear Information System (INIS)

Atun, G.

2002-01-01

The heterogeneous isotopic exchange reactions in strontium polymolybdates of Sr 2+ and MoO 4 2- ions in the strontium nitrate and sodium molybdate solutions have been studied using 90 Sr and 99 Mo as tracers. Electrometric methods have been used to study the compositions of strontium molybdates obtained by adding strontium chloride to a progressively acidified solution of sodium molybdate. It has been found that the exchange fraction increases with increasing chain length of strontium polymolybdate. The exchange equilibrium constant (K ex ) has been calculated between 298 and 348 K as well as ΔG deg, ΔH deg and ΔS deg. The results indicate that Sr 2+ cations have a much higher affinity for exchangers than MoO 4 2- anions. By fitting the data to the Dubinin-Radushkevich (D-R) isotherm it has been shown that the exchange capacity (X m ) for both ions is affected by the ion adsorption process at low temperatures and by the ion exchange process at high temperatures. At high concentrations, the recrystallization process contributes to on the cation exchange but is ineffective on the anion exchange mechanism. (author)

High-resolution stratigraphy with strontium isotopes.

Science.gov (United States)

Depaolo, D J; Ingram, B L

1985-02-22

The isotopic ratio of strontium-87 to strontium-86 shows no detectable variation in present-day ocean water but changes slowly over millions of years. The strontium contained in carbonate shells of marine organisms records the ratio of strontium-87 to strontium-86 of the oceans at the time that the shells form. Sedimentary rocks composed of accumulated fossil carbonate shells can be dated and correlated with the use of high precision measurements of the ratio of strontium-87 to strontium-86 with a resolution that is similar to that of other techniques used in age correlation. This method may prove valuable for many geological, paleontological, paleooceanographic, and geochemical problems.

Rubidium-strontium method

International Nuclear Information System (INIS)

Dubansky, A.

1980-01-01

The rubidium-strontium geological dating method is based on the determination of the Rb and Sr isotope ratio in rocks, mainly using mass spectrometry. The method is only practical for silicate minerals and rocks, potassium feldspars and slates. Also described is the rubidium-strontium isochrone method. This, however, requires a significant amount of experimental data and an analysis of large quantities of samples, often of the order of tons. The results are tabulated of rubidium-strontium dating of geological formations in the Czech Socialist Republic. (M.S.)

Kinetics of isotopic exchange between strontium polymolybdate and strontium ions in aqueous solution

International Nuclear Information System (INIS)

Atun, Gulten; Bilgin, Binay; Kilislioglu, Ayben

2002-01-01

A heterogeneous isotopic exchange reaction of strontium polymolybdate in strontium chloride solution was studied using 90 Sr as a tracer. The effects of low and high strontium chloride concentration on the rate and mechanism of the isotopic exchange reaction were investigated. It was found that, at high concentrations, the rate is independent of strontium concentration, but, at low concentrations, the rate is proportional to the strontium concentration. These results support a hypothesis that, at low concentrations, the rate is controlled by film diffusion, whereas at high concentrations it is controlled by particle diffusion. Experiments were performed at 293, 303 and 313 K. Activation energy of isotopic exchange reaction and thermodynamic parameters ΔH*, ΔS*, and ΔG* were calculated using the Arrhenius and Eyring equations. The results also indicated that recrystallization is a predominant factor in the present exchange reaction

Kinetics of isotopic exchange between strontium polymolybdate and strontium ions in aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Atun, Gulten E-mail: gultena@istanbul.edu.tr; Bilgin, Binay; Kilislioglu, Ayben

2002-06-01

A heterogeneous isotopic exchange reaction of strontium polymolybdate in strontium chloride solution was studied using {sup 90}Sr as a tracer. The effects of low and high strontium chloride concentration on the rate and mechanism of the isotopic exchange reaction were investigated. It was found that, at high concentrations, the rate is independent of strontium concentration, but, at low concentrations, the rate is proportional to the strontium concentration. These results support a hypothesis that, at low concentrations, the rate is controlled by film diffusion, whereas at high concentrations it is controlled by particle diffusion. Experiments were performed at 293, 303 and 313 K. Activation energy of isotopic exchange reaction and thermodynamic parameters {delta}H*, {delta}S*, and {delta}G* were calculated using the Arrhenius and Eyring equations. The results also indicated that recrystallization is a predominant factor in the present exchange reaction.

Measurement of strontium-89 and strontium-90 in environmental waters. A tentative reference method

International Nuclear Information System (INIS)

1976-03-01

A tentative reference method for the measurement of 89 Sr and 90 Sr in environmental waters is described. Samples of environmental water sources are collected, preserved with acid-strontium carrier, and analyzed for 89 Sr and/or 90 Sr. The isotopes are separated from the sample water by precipitating with stable strontium carrier as carbonate. The strontium carbonate is dissolved, 90 Sr separated, the strontium reprecipitated as carbonate, filtered, and counted for the combined 89 Sr and 90 Sr activity. The 90 y is allowed to grow in from the 90 y activity; the strontium carbonate is redissolved; the 90 y is separated, precipitated, and counted for the 90 Sr determination. The 89 Sr activity is then determined by difference of the total 89 Sr and 90 y and the separate 90 Sr activities. Recoveries are determined from the added and found (recovered) strontium carrier. Counting efficiencies are determined with prepared standard reference samples. Results are reported in pCi/liter

A study of strontium doped calcium phosphate coatings on AZ31

International Nuclear Information System (INIS)

Singh, Satish S.; Roy, Abhijit; Lee, Boeun E.; Ohodnicki, John; Loghmanian, Autrine; Banerjee, Ipsita; Kumta, Prashant N.

2014-01-01

Calcium phosphate (CaP) coatings have been studied to tailor the uncontrolled non-uniform corrosion of Mg based alloys while simultaneously enhancing bioactivity. The use of immersion techniques to deposit CaP coatings is attractive due to the ability of the approach to coat complex structures. In the current study, AZ31 substrates were subjected to various pretreatment conditions prior to depositing Sr 2+ doped and undoped CaP coatings. It was hypothesized that the bioactivity and corrosion protection of CaP coatings could be improved by doping with Sr 2+ . Heat treatment to elevated temperatures resulted in the diffusion of alloying elements, Mg and Zn, into the pretreated layer. Sr 2+ doped and undoped CaP coatings formed on the pretreated substrates consisted of biphasic mixtures of β-tricalcium phosphate (β-TCP) and hydroxyapatite (HA). Electrochemical corrosion experiments indicated that the extent of Sr 2+ doping and pretreatment both influenced the corrosion protection. Cytotoxicity was evaluated with MC3T3-E1 mouse preosteoblasts and human mesenchymal stem cells (hMSCs). For both cell types, proliferation decreased upon increasing the Sr 2+ concentration. However, both osteogenic gene and protein expression significantly increased upon increasing Sr 2+ concentration. These results suggest that Sr 2+ doped coatings are capable of promoting osteogenic differentiation on degradable Mg alloys, while also enhancing corrosion protection, in comparison to undoped CaP coatings

Calcium and Strontium in Swedish Waters and Fish, and Accumulation of Strontium-90

Energy Technology Data Exchange (ETDEWEB)

Agnedal, P O

1966-04-15

The purpose of this study has been to investigate the correlation between calcium and strontium in fish in relation to the concentration of these elements in the water. An investigation of the uptake of strontium-90 has also been made and permissible levels of strontium-90 in the water is calculated based upon the uptake in fish muscle tissues. Lakes with calcium concentrations between 2 - 63 mg/l have been studied and samples from the Baltic coastal water are also included. Three fish species are studied, viz. pike (Esox lucius (L.)), perch (Perca fluviatilis (L.)) and roach (Leuciscus rutilus (L.)). Bones, muscle tissues and skin + scales have been analysed. Strontium-90 measurements have been made showing an increase in both water and fish. Calculations show that in water with about 2 mg Ca/l a 10-fold increase of the existing strontium-90 level might give strontium-90 concentrations in fish muscle tissues close to what is permissible. In lakes with calcium concentrations 20 - 40 mg/l the permissible levels for drinking water will be exceeded before the fish consumption would have to be restricted.

Calcium and Strontium in Swedish Waters and Fish, and Accumulation of Strontium-90

International Nuclear Information System (INIS)

Agnedal, P.O.

1966-04-01

The purpose of this study has been to investigate the correlation between calcium and strontium in fish in relation to the concentration of these elements in the water. An investigation of the uptake of strontium-90 has also been made and permissible levels of strontium-90 in the water is calculated based upon the uptake in fish muscle tissues. Lakes with calcium concentrations between 2 - 63 mg/l have been studied and samples from the Baltic coastal water are also included. Three fish species are studied, viz. pike (Esox lucius (L.)), perch (Perca fluviatilis (L.)) and roach (Leuciscus rutilus (L.)). Bones, muscle tissues and skin + scales have been analysed. Strontium-90 measurements have been made showing an increase in both water and fish. Calculations show that in water with about 2 mg Ca/l a 10-fold increase of the existing strontium-90 level might give strontium-90 concentrations in fish muscle tissues close to what is permissible. In lakes with calcium concentrations 20 - 40 mg/l the permissible levels for drinking water will be exceeded before the fish consumption would have to be restricted

Rapid determination of strontium-89 and strontium-90 in food and environmental samples by Cerenkov counting

International Nuclear Information System (INIS)

Melin, Judith; Suomela, Jorma

1995-01-01

The method has been developed for emergency situations. Minimum detectable concentrations of 5 Bq/liter, kilogram of strontium-89 and strontium-90 respectively is achievable in the presence of nuclides considered to be released under accidental conditions. Result on the strontium-89 and strontium-90 content in a sample can be obtained within 12 hours. One technician can easily handle 8-10 samples during a working day of eight hours. The determination of the strontium isotopes is accomplished by monitoring the Cerenkov radiation from strontium-89 and yttrium-90 in a liquid scintillation counter. The latter is the daughter product of strontium-90. Prior to the Cerenkov counting the sample is separated from interfering nuclides by oxalate precipitation, chromate precipitation and HDEHP-extraction. The method has to be further improved and evaluated with respect to different soil types such as forest mineral soil layers, agricultural soils and pastures. Furthermore, the decontamination procedure should be evaluated for a sample containing freshly irradiated uranium. (author)

Simulating the Transfer of Strontium-90 from Soil to Leafy Vegetables by Using Strontium-88

OpenAIRE

Kuke, Ding; Shujuan, Liu; Yingxue, He; Dong, Yan; Fengshou, Zhang; Shuifeng, Wang; Jinghua, Guo; Wei, Zhang; Xin, Wang; Xiaoyan, Jiang

2016-01-01

The transfer, from soil to Chinese cabbage and spinach, of radioactive strontium-90 released as a result of accidents in nuclear power stations was studied using a stable isotope of strontium, namely nuclide strontium-88 (88Sr). The study led to an experimental model for assessing the hazard of radionuclide strontium-90 (90Sr) entering the food chain and for predicting the risk to food safety. Chinese cabbage and spinach were grown in pots in a greenhouse and irrigated with deionized water co...

Role of glass structure in defining the chemical dissolution behavior, bioactivity and antioxidant properties of zinc and strontium co-doped alkali-free phosphosilicate glasses.

Science.gov (United States)

Kapoor, Saurabh; Goel, Ashutosh; Tilocca, Antonio; Dhuna, Vikram; Bhatia, Gaurav; Dhuna, Kshitija; Ferreira, José M F

2014-07-01

We investigated the structure-property relationships in a series of alkali-free phosphosilicate glass compositions co-doped with Zn(2+) and Sr(2+). The emphasis was laid on understanding the structural role of Sr(2+) and Zn(2+) co-doping on the chemical dissolution behavior of glasses and its impact on their in vitro bioactivity. The structure of glasses was studied using molecular dynamics simulations in combination with solid state nuclear magnetic resonance spectroscopy. The relevant structural properties are then linked to the observed degradation behavior, in vitro bioactivity, osteoblast proliferation and oxidative stress levels. The apatite-forming ability of glasses has been investigated by X-ray diffraction, infrared spectroscopy and scanning electron microscopy-energy-dispersive spectroscopy after immersion of glass powders/bulk in simulated body fluid (SBF) for time durations varying between 1h and 14 days, while their chemical degradation has been studied in Tris-HCl in accordance with ISO 10993-14. All the glasses exhibit hydroxyapatite formation on their surface within 1-3h of their immersion in SBF. The cellular responses were observed in vitro on bulk glass samples using human osteosarcoma MG63 cell line. The dose-dependent cytoprotective effect of glasses with respect to the concentration of zinc and strontium released from the glasses is also discussed. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Neodymium-doped Sr5(PO4)3F and Sr5(VO4)3F

International Nuclear Information System (INIS)

Corker, D.L.; Nicholls, J.; Loutts, G.B.

1995-01-01

Neodymium-doped Sr 5 (PO 4 ) 3 F [neodymium strontium fluoride phosphate, (Nd,Sr) 5 (PO 4 ) 3 F] and neodymium-doped Sr 5 (VO 4 ) 3 F [neodymium strontium fluoride vanadate, (Nd,Sr) 5 (VO 4 ) 3 F] crystallize in space group P6 3 /m and are isostructural with calcium fluorophosphate, Ca 5 (PO 4 ) 3 F. There are two different Sr sites in Sr 5 (XO 4 ) 3 F, denoted Sr(1) and Sr(2). Using single-crystal X-ray diffraction the two structures were refined to R factors of 2.3 and 2.2%, respectively, showing that Nd is present at both Sr sites in (Sr,Nd) 5 (VO 4 ) 3 F but only at the Sr(2) site in (Sr,Nd) 5 (PO 4 ) 3 F. (orig.)

Strontium-82/rubidium-82 generator

International Nuclear Information System (INIS)

Gennaro, G.P.; Haney, P.S.

1986-01-01

Hydroxylapatite, a compound having the formula: M 10 (PO 4 ) 6 (OH) 2 wherein M is calcium, strontium, barium, lead, iron, sodium, potassium, zinc, cadmium, magnesium, aluminium or a rare earth metal, is provided as a support medium for strontium-82 in a strontium-82/rubidium-82 parent-daughter radionuclide generator

Strontium doping promotes bioactivity of rhBMP-2 upon calcium phosphate cement via elevated recognition and expression of BMPR-IA.

Science.gov (United States)

Huang, Baolin; Tian, Yu; Zhang, Wenjing; Ma, Yifan; Yuan, Yuan; Liu, Changsheng

2017-11-01

Preserving and improving osteogenic activity of bone morphogenetic protein-2 (BMP-2) upon implants remains one of the key limitations in bone regeneration. With calcium phosphate cement (CPC) as model, we have developed a series of strontium (Sr)-doped CPC (SCPC) to address this issue. The effects of fixed Sr on the bioactivity of recombinant human BMP-2 (rhBMP-2) as well as the underlying mechanism were investigated. The results suggested that the rhBMP-2-induced osteogenic activity was significantly promoted upon SCPCs, especially with a low amount of fixed Sr (SrCO 3 content IA (BMPR-IA) to rhBMP-2 and an increased expression of BMPR-IA in C2C12 model cells. As a result, the activations of BMP-induced signaling pathways were different in C2C12 cells incubated upon CPC/rhBMP-2 and SCPCs/rhBMP-2. These findings explicitly decipher the mechanism of SCPCs promoting osteogenic bioactivity of rhBMP-2 and signify the promising application of the SCPCs/rhBMP-2 matrix in bone regeneration implants. Copyright © 2017 Elsevier B.V. All rights reserved.

Sintering and electrical properties of strontium-doped lanthanum manganite

Energy Technology Data Exchange (ETDEWEB)

Tarrago, Diego Pereira; Sousa, Vania Caldas de [Universidade Federal do Rio Grande do Sul (LABIOMAT/PPGEM/UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia de Minas, Metalurgica e de Materiais. Lab. de Biomateriais], Email: dptarrago@gmail.com; Moreno Buriel, Berta; Chinarro Martini, Eva; Jurado Egea, Jose Ramon [Consejo Superior de Investigaciones Cientificas (ICV/CSIC), Madrid (Spain). Inst. de Ceramica y Vidrio; Malfatti, Celia de Fraga [Universidade Federal do Rio Grande do Sul (LAPEC/PPGEM/UFRGS), Porto Alegre, RS (Brazil). Programa de Pos-Graduacao em Engenharia de Minas, Metalurgica e de Materiais. Lab. de Pesquisa em Corrosao

2010-07-01

Lanthanum strontium manganites (LSM) are potential materials for cathode applications in solid oxide fuel cells (SOFC) due to their good catalytic activity, chemical stability and compatibility with electrolyte materials in high temperatures. The sinterability of single phase La{sub 1-x}Sr{sub x}Mn{sub O3} (x=0.18) perovskite powders and the electrical properties of the resulting samples are analyzed in this study. Using a heating microscope, the powders were pressed and sintered at different pressures and temperatures, resulting in an open porosity of 33.36% when compacted at 125 MPa and sintered at 1200 degree C. Top and cross-section s canning electron microscopy (SEM) micrographs revealed interconnected pores in the sintered body and, hence, a suitable microstructure for the application. The activation energy for conductance was 0.04 eV and the tested LSM bulk started to exhibit adequate electrical properties at about 500 degree C. (author)

Magnetic and electromagnetic properties of Pr doped strontium ferrite/polyaniline composite film

Energy Technology Data Exchange (ETDEWEB)

Huang, Ying; Li, Yuqing; Wang, Yan, E-mail: wangyan287580632@126.com

2014-11-15

This paper reported three acid (including hydrochloric acid HCl, p-toluenesulfonic acid PTS and D-camphor-10-acid CSA) doped SrPr{sub 0.2}Fe{sub 11.8}O{sub 19}/PANI composite film and the HCl–PANI film prepared by a sol–gel method and in-situ oxidative polymerization. The characteristics of the film phase structure, surface morphology, conductivity and magnetic and electromagnetic properties were studied by using XRD, XPS, FESEM, four-probe tester, VSM and Vector Network Analyzer. The resistivity of organic acid doped composite films is higher than that of the HCl doped one. The saturation and remanent magnetization of PTS and HCl doped composite films are greater than the CSA-doped one; however, the coercivity of the three acid doped composite films is basically 5546 Oe. The saturation magnetization, remanent magnetization and coercivity of SrPr{sub 0.2}Fe{sub 11.8}O{sub 19} film are greater than those of the SrPr{sub 0.2}Fe{sub 11.8}O{sub 19}–PANI composite film. In the frequency range of 8–12 GHz, the dielectric loss of HCl–PANI film is the maximum, and the dielectric loss of SrPr{sub 0.2}Fe{sub 11.8}O{sub 19} film is the minimum; the magnetic loss of the four films is in descending order as SrPr{sub 0.2}Fe{sub 11.8}O{sub 19} film, PrSrM/(HCl–PANI) composite film, PrSrM/(CSA–PANI) and HCl–PANI film. - Highlights: • Synthesizing three acid doped SrPr{sub 0.2}Fe{sub 11.8}O{sub 19}/PANI composite films. • By sol–gel method and in-situ oxidative polymerization. • With excellent magnetic and electromagnetic properties. • The particular coating structure of PANI and Sr-ferrite. • Great interest for magnetic material and microwave absorbers.

Trivalent europium-doped strontium molybdate red phosphors in white light-emitting diodes: Synthesis, photophysical properties and theoretical calculations

International Nuclear Information System (INIS)

Yang, W.-Q.; Liu, H.-G.; Liu, G.-K.; Lin, Y.; Gao, M.; Zhao, X.-Y.; Zheng, W.-C.; Chen, Y.; Xu, J.; Li, L.-Z.

2012-01-01

Eu 3+ -doped strontium molybdate red phosphors (Sr 1−x MoO 4 :Eu x (x = 0.01–0.2)) for white light-emitting diodes (LED) were synthesized by the solid-state reaction method. The fluorescent intensities of the as-prepared phosphors were remarkably improved. The excitation and emission spectra demonstrate that these phosphors can be effectively excited by the near-UV light (395 nm) and blue light (466 nm). Their emitted red light peaks are located at 613 nm, and the highest quantum yield value (η) of the as-grown red phosphor, which is 95.85%, is much higher than that of commercial red phosphor (77.53%). These red phosphors plus commercial yellow powers (1:10) were successfully packaged with the GaN-based blue chips on a piranha frame by epoxy resins. The encapsulated white LED lamps show high performance of the CIE chromaticity coordinates and color temperatures. Moreover, to explain the fluorescent spectra of these phosphors, a complete 3003 × 3003 energy matrix was successfully built by an effective operator Hamiltonian including free ion and crystal field interactions. For the first time, the fluorescent spectra for Eu 3+ ion at the tetragonal (S 4 ) Sr 2+ site of SrMoO 4 crystal were calculated from a complete diagonalization (of energy matrix) method. The fitting values are close to the experimental results.

Combined transuranic-strontium extraction process

Science.gov (United States)

Horwitz, E. Philip; Dietz, Mark L.

1992-01-01

The transuranic (TRU) elements neptunium, plutonium and americium can be separated together with strontium from nitric acid waste solutions in a single process. An extractant solution of a crown ether and an alkyl(phenyl)-N,N-dialkylcarbanylmethylphosphine oxide in an appropriate diluent will extract the TRU's together with strontium, uranium and technetium. The TRU's and the strontium can then be selectively stripped from the extractant for disposal.

The effect of strontium and barium doping on perovskite-structured energy materials for photovoltaic applications

Science.gov (United States)

Wu, Ming-Chung; Chen, Wei-Cheng; Chan, Shun-Hsiang; Su, Wei-Fang

2018-01-01

Perovskite solar cell is a novel photovoltaic technology with the superior progress in efficiency and the simple solution processes. Develop lead-free or lead-reduced perovskite materials is a significant concern for high-performance perovskite solar cell. Among the alkaline earth metals, the Sr2+ and Ba2+ are suitable for Pb2+ replacement in perovskite film due to fitting Goldschmidt's tolerance factor. In this study, we adopted Ba-doped and Sr-doped perovskite structured materials with different doping levels, including 1.0, 5.0, and 10.0 mol%, to prepare perovskite solar cells. Both Ba-doped and Sr-doped perovskite structured materials have a related tendency in absorption behavior and surface morphology. At 10.0 mol% doping level, the power conversion efficiency (PCE) of Sr-doped perovskite solar cells is only ∼0.5%, but the PCE of Ba-doped perovskite solar cells can be achieved to ∼9.7%. Ba-doped perovskite solar cells showed the acceptable photovoltaic characteristics than Sr-doped perovskite solar cells. Ba dopant can partially replace the amount of lead in the perovskite solar cells, and it could be a potential candidate in the field of lead-free or lead-reduced perovskite energy materials.

Phase stability and processing of strontium and magnesium doped lanthanum gallate

Science.gov (United States)

Zheng, Feng

Fuel Cells are one of the most promising energy transformers with respect to ecological and environmental issues. Solid Oxide Fuel Cells (SOFC) are all solid-state devices. One of the challenges to improve a SOFC is to lower the operating temperature while maintaining or increasing its output voltage. Undoped LaGaO3 is an insulator, doping transforms it into an oxygen-ionic conductor. Sr and Mg doped LaGaO3 (LSGM) perovskite is a new oxygen-ionic conductor with higher conductivity than yttria-stabilized zirconia (YSZ). This material is a candidate for a wide variety of electrochemical devices. In order to realize this potential, the phase stability and processing of this material needs to be investigated in detail. In this study, a systematic investigation of the LSGM materials in terms of phase stability, phase transition, sintering, microstructure and electrical conductivity as functions of temperature, doping content and A/B cation ratio has been carried out. The generalized formula of the materials investigated is (La1--xSrx)A(Ga1--yMg y)BO3--delta. Optimized processing parameters have been obtained by investigating their impact on density change and microstructure. Consequently, a suitable compositional window of the LSGM perovskite has been identified for SOFC electrolyte applications. Based on detailed diffraction analysis, it is found that the undoped LaGaO3 takes on the orthorhombic (Pbnm) symmetry at room temperature. This structure changes to rhombohedral (R3c) at 147 +/- 2°C or changes to monoclinic (I2/a) when the doping level increases from 0.1 to 0.2 moles. We have optimized the compositional window to make the single perovskite phase with high oxygen ionic conductivity (x = 0.10 to 0.20 with A/B ratio between 0.98 to 1.02). The best processing condition, starting from glycine nitrate process (GNP) combustion synthesized ultra-fine LSGM powder, is sintering in air at 1500°C for 2 hours. The doped material has higher oxygen ionic conductivity than

Dielectric properties of calicum and barium-doped strontium titanate

Science.gov (United States)

Tung, Li-Chun

Dielectric properties of high quality polycrystalline Ca- and Ba-doped SrTiO3 perovskites are studied by means of dielectric constant, dielectric loss and ferroelectric hysteresis measurements. Low frequency dispersion of the dielectric constant is found to be very small and a simple relaxor model may not be able to explain its dielectric behavior. Relaxation modes are found in these samples, and they are all interpreted as thermally activated Bipolar re-orientation across energy barriers. In Sr1- xCaxTiO3 (x = 0--0.3), two modes are found associated with different relaxation processes, and the concentration dependence implies a competition between these processes. In Sr1-xBa xTiO3 (x = 0--0.25), relaxation modes are found to be related to the structural transitions, and the relaxation modes persist at low doping levels (x Barret formula is discussed and two of the well-accepted models, anharmonic oscillator model and transverse Ising model, are found to be equivalent. Both of the Ca and Ba systems can be understood qualitatively within the concept of transverse Ising model.

Deposition of strontium and calcium in snail shell

Energy Technology Data Exchange (ETDEWEB)

Rosenthal, Jr, G M; Nelson, D J; Gardiner, D A

1965-07-03

The relative effects of strontium and calcium concentrations in the environment on their uptake and incorporation into snail shell were investigated. /sup 45/Ca and /sup 85/Sr were used as tracers and specific activities were used to determine deposition. Data are presented in tables and graphs. Deposition of both calcium and strontium in the snail shell depended primarily on the respective concentrations of these elements in the immediate environment. A slight effect of strontium on calcium deposition was observed. There was found to be a minimum strontium deposition for various combinations of strontium and calcium in the environment. It was concluded that strontium uptake is more closely associated with environmental strontium concentrations than with calcium concentrations.

A new method for the preparation of strontium titanate and strontium hypovanadate

International Nuclear Information System (INIS)

Balasubramanian, M.R.

1985-01-01

Strontium titanate has been a prized chemical by virtue of its dielectric, photoelectric and surface properties. The compound crystallises with the cubic perovskite structure. Till now only two techniques (and a few variants therein) have been employed for its synthesis, one of them is a solid state reaction between SrCO 3 and TiO 2 at 1100deg, and the other is a coprecipitation of strontium titanyl oxalate followed by calcination at 850deg. As ternary oxides, such as copper chromite, have been prepared by complex formation, the author found it interesting to apply this method to the preparation of strontium titanate. The most easily accessible and versatile complexing agent, EDTA, was used. (author)

Tailoring structure and magnetic characteristics of strontium hexaferrite via Al doping engineering

Energy Technology Data Exchange (ETDEWEB)

Wang, H.Z.; Hai, Y.N. [State Key Lab of High Power Semiconductor Laser of Changchun University Science and Technology, Changchun University Science and Technology, Changchun 130022 (China); Yao, B., E-mail: binyao@jlu.edu.cn [State Key Lab of Superhard Materials and Department of Physics, Jilin University, Changchun 130023 (China); Xu, Y. [School of Physics, Northeast Normal University, Changchun 130024 (China); Shan, L. [State Key Laboratory of Inorganic Synthesis and Preparative Chemistry and Department of Chemistry, Jilin University, Changchun 130012 (China); Xu, L.; Tang, J.L.; Wang, Q.H. [State Key Lab of High Power Semiconductor Laser of Changchun University Science and Technology, Changchun University Science and Technology, Changchun 130022 (China)

2017-01-15

Emerging structure and magnetic properties of Al{sup 3+}-modified SrFe{sub 12}O{sub 19} M-type hexaferrite system (SrAl{sub x}Fe{sub 12−x}O{sub 19}) had been studied in detail via doping engineering. With Al{sup 3+} ion nominal content ranging from 0 to 4 (0≤x≤4), the lattice parameters decrease due to the substitution of Fe{sup 3+} ions by smaller Al{sup 3+} ions, and the magnetization shows a continuous reduction with the increasing of Al content. For the coercivity, its value initially increases, reaching a maximum value of 16,876.9 Oe at x=3, and then reduces with the Al content further increase. When all the Fe{sup 3+} ions (x=4) are replaced by Al{sup 3+} ions, the net magnetic moment will be closed to zero, that will weaken the exchange interaction between Fe{sup 3+} ions, resulting in decrease of coercivity sharply and transformation ferrimagnetism into antiferromagnetism. The mechanism of the improvement of the magnetic properties induced by Al doping is discussed in the present work. - Highlights: • The coercivity reach a maximum value at x=3 in the SrAl{sub x}Fe{sub 12−x}O{sub 19}. • The coercivity of SrFe{sub 12}O{sub 19} increases due to nonmagnetic Al doping. • The saturation magnetization of SrFe{sub 12}O{sub 19} decreases due to nonmagnetic Al doping. • The transformation ferrimagnetism into antiferromagnetism by nonmagnetic Al doping.

Determination of radioactive strontium in seawater

International Nuclear Information System (INIS)

Grahek, Zeljko; Rozmaric Macefat, Martina

2005-01-01

This paper describes the procedures of isolating strontium and yttrium from seawater that enable the determination of 89,90 Sr. In one procedure, strontium is directly isolated from seawater on the column filled with Sr resin by binding of strontium to the resin from 3 M HNO 3 in a seawater, and successive elution with HNO 3 . In others, strontium is precipitated from seawater with (NH 4 ) 2 CO 3 , followed by isolation on a Sr column or an anion exchange column. It is shown that strontium precipitation is optimal with concentration of 0.3 M (NH 4 ) 2 CO 3 at pH = 11. In these conditions, 100% Y, 78% Sr, 80% Ca and 50% Mg are precipitated. Strontium is bound on to Sr column from 5 to 8 M HNO 3 , separated from other elements by elution with 3 M HNO 3 and 0.05 M HNO 3 . Strontium and yttrium are bound on to anion exchange column from alcoholic solutions of nitric acid. The optimum mixture of alcohols for sample binding is a mixture of ethanol and methanol with the volume ratio 1:3. Strontium and yttrium are separated from Mg, Ca, K, and other elements by elution with 0.25 M HNO 3 in the mixture of ethanol and methanol. After the separation, yttrium and strontium are eluted from the column with water or methanol. In the procedure of direct isolation from 1 l of the sample, the average recovery of 50% was obtained. In the remaining two procedures, the strontium recovery was about 60% for the Sr column and 65% for anion exchange column. Recovery of yttrium is about 70% for the anion exchange column. It turned out that the procedure with the Sr resin (direct isolation and isolation after precipitation) is simpler and faster in the phase of the isolation on the column in comparison with the procedure with the anion exchanger. The procedure with the anion exchanger, however, enables the simultaneous isolation of yttrium and strontium and rapid determination of 89,90 Sr. These procedures were tested by determination of 89,90 Sr on liquid scintillation counter and Cherenkov

Removal of Strontium from Drinking Water by Conventional ...

Science.gov (United States)

The United States Environmental Protection Agency Contaminant Candidate List 3 lists strontium as a contaminant for potential regulatory consideration in drinking water. There is very little data available on strontium removal from drinking water. As a result, there is an immediate need to perform treatment studies. The objective of this work is to evaluate the effectiveness of conventional and lime-soda ash softening treatments to remove strontium from surface and ground waters. Conventional drinking water treatment with aluminum and iron coagulants were able to achieve 12% and 5.9% strontium removal at best, while lime softening removed as much as 78% from natural strontium-containing ground water. Systematic fundamental experiments showed that strontium removal during the lime-soda ash softening was related to pH, calcium concentration and dissolved inorganic carbon concentration. Final strontium concentration was also directly associated with initial strontium concentration. Precipitated solids showed well-formed crystals or agglomerates of mixed solids, two polymorphs of calcium carbonate (vaterite and calcite), and strontianite, depending on initial water quality conditions. X-ray diffraction analysis suggested that strontium likely replaced calcium inside the crystal lattice and was likely mainly responsible for removal during lime softening. To inform the public.

Strontium-90 fluoride data sheet

Energy Technology Data Exchange (ETDEWEB)

Fullam, H.T.

1981-06-01

This report is a compilation of available data and appropriate literature references on the properties of strontium-90 fluoride and nonradioactive strontium fluoride. The objective of the document is to compile in a single source pertinent data to assist potential users in the development, licensing, and use of /sup 90/SrF/sub 2/-fueled radioisotope heat sources for terrestrial power conversion and thermal applications. The report is an update of the Strontium-90 Fluoride Data Sheet (BNWL-2284) originally issued in April 1977.

Spin injection and detection in lanthanum- and niobium-doped SrTiO3 using the Hanle technique

KAUST Repository

Han, Wei; Jiang, Xin; Kajdos, Adam; Yang, See-Hun; Stemmer, Susanne; Parkin, Stuart S. P.

2013-01-01

as the temperature is decreased to low temperatures. However, the mobility of the strontium titanate has a strong temperature dependence. This behaviour and the carrier doping dependence of the spin lifetime suggest that the spin lifetime is limited by spin

Understanding the defect chemistry of alkali metal strontium silicate solid solutions: insights from experiment and theory

KAUST Repository

Bayliss, Ryan D.; Cook, Stuart N.; Scanlon, David O.; Fearn, Sarah; Cabana, Jordi; Greaves, Colin; Kilner, John A.; Skinner, Stephen J.

2014-01-01

© the Partner Organisations 2014. Recent reports of remarkably high oxide ion conduction in a new family of strontium silicates have been challenged. It has recently been demonstrated that, in the nominally potassium substituted strontium germanium silicate material, the dominant charge carrier was not the oxygen ion, and furthermore that the material was not single phase (R. D. Bayliss et. al., Energy Environ. Sci., 2014, DOI: 10.1039/c4ee00734d). In this work we re-investigate the sodium-doped strontium silicate material that was reported to exhibit the highest oxide ion conductivity in the solid solution, nominally Sr0.55Na0.45SiO2.775. The results show lower levels of total conductivity than previously reported and sub-micron elemental mapping demonstrates, in a similar manner to that reported for the Sr0.8K0.2Si0.5Ge0.5O2.9 composition, an inhomogeneous chemical distribution correlating with a multiphase material. It is also shown that the conductivity is not related to protonic mobility. A density functional theory computational approach provides a theoretical justification for these new results, related to the high energetic costs associated with oxygen vacancy formation. This journal is

Understanding the defect chemistry of alkali metal strontium silicate solid solutions: insights from experiment and theory

KAUST Repository

Bayliss, Ryan D.

2014-09-24

© the Partner Organisations 2014. Recent reports of remarkably high oxide ion conduction in a new family of strontium silicates have been challenged. It has recently been demonstrated that, in the nominally potassium substituted strontium germanium silicate material, the dominant charge carrier was not the oxygen ion, and furthermore that the material was not single phase (R. D. Bayliss et. al., Energy Environ. Sci., 2014, DOI: 10.1039/c4ee00734d). In this work we re-investigate the sodium-doped strontium silicate material that was reported to exhibit the highest oxide ion conductivity in the solid solution, nominally Sr0.55Na0.45SiO2.775. The results show lower levels of total conductivity than previously reported and sub-micron elemental mapping demonstrates, in a similar manner to that reported for the Sr0.8K0.2Si0.5Ge0.5O2.9 composition, an inhomogeneous chemical distribution correlating with a multiphase material. It is also shown that the conductivity is not related to protonic mobility. A density functional theory computational approach provides a theoretical justification for these new results, related to the high energetic costs associated with oxygen vacancy formation. This journal is

The effect of CHA-doped Sr addition to the mechanical strength of metakaolin dental implant geopolymer composite

Science.gov (United States)

Sunendar, Bambang; Fathina, Afiya; Harmaji, Andrie; Mardhian, Deby Fajar; Asri, Lia; Widodo, Haris Budi

2017-09-01

The prospective material for implant plate required sufficient mechanical properties to maintain fracture fixation and resist physiological stress until bone healing process finished. Various problem implant plate based on metal and polymer materials when used as fixation for bone defect case induced developmental of bioceramic for implant plate materials. Materials that now has been attract a lot of attention is carbonate apatite and strontium as doping which known to have good biocompability along with biointegrity and mechanical charateristics. Other materials that have been known to have good mechanical properties are metakaolin and use of chitosan as coupling agent. Metakaolin and carbonate apatite can be produced by sol-gel methode which simpler, economical and energy-saving procedure furthermore use of chitosan which is widely found in the nature of Indonesia can be used to encourage the utilization of natural resources. The aim fo this paper is to investigated effect of CHA-doped Sr 5 (%) mol addition to the mechanical strength of metakaolin dental implant geoploymer composite. In this paper metakaolin is used as geopolymerization precursors. The test results have shown that addition of filler of apatite carbonate doped 5% mol strontium can be said to increase the value of mechnical properties but high concentration of calcium in the nanocomposite also can complicate the equilibrium of the geopolymerization process and induce alkali aggregate reactivity (AAR). The sample group of nanocomposite of metakaolin and carbonate apatite-doped 5% mol strontium (2: 1% wt) with 2% chitosan as a coupling agent based on geopolymerization for implant plate application has the best mechanical properties among all sample groups but does not qualify as an implant plate on cortical bone but can be used for the application of the implant plate on the trabecular bone specifically and potentially as a bone initiator.

Influence of reactor irradiation on the protons intercalation and stability of barium cerates and strontium cerates

International Nuclear Information System (INIS)

Aksenova, T.I.; Khromushin, I.V.; Zhotabaev, Zh.R.; Kornienko, P.A.; Munasbaeva, K.K.

2005-01-01

The work is devoted to study of reactor irradiation influence on the gas-solid exchange processes in the high-temperature proton semiconductors on the base of cerates and strontium. A number of new regularities of influence of content of some proton semiconductors on the gas-solid exchange processes was established. It is shown, that increase of rate of cation doping rate leads to considerable lowering in its of carbonic gas content, and therefore to improvement their tribological properties. It is revealed, that irradiation of polycrystalline samples leads to growth of oxygen amount desorbed from samples, whereas irradiation of monocrystalline samples practically does not has effect on the desorbed oxygen amount. It was found, that character of relation of intercalated in the sample protons depend on sample doping rate

Strontium isotopic study of sediment from the Ross Sea

International Nuclear Information System (INIS)

Kovach, J.; Faure, G.

1977-01-01

A preliminary report summarizing the results of a study of the strontium-87/strontium-86 ratios and of the rubidium and strontium concentrations of the fine-grained (less than 150 microns) noncarbonate fractions of sediment samples from core E32-25 raised from a depth of 327 fathoms in the Ross Sea at 78 0 31.0'S 164 0 24.7'W was presented. The strontium-87/strontium-86 ratios of the samples analyzed range from 0.7119 to 0.7220. Rubidium and strontium concentrations range, respectively, from 126 to 164 parts per million and from 113 to 174 parts per million. The observed strontium-87/strontium-86 ratios and strontium concentrations in sediment samples from core E32-25 fit a hyperbolic curve. These ratios can be used to estimate the concentrations of volcanogenic detritus in the sediment samples. The results of this study provide additional baseline data for anticipated future studies of sediment cores to be recovered from beneath the Ross Ice Shelf by the Ross Ice Shelf Project. 1 figure

Effect of yttrium chromite doping on its resistance to high-temperature salt and gas corrosions

International Nuclear Information System (INIS)

Oryshich, I.V.; Poryadchenko, N.E.; Rakitskij, A.N.; Bega, N.D.

1996-01-01

Effect of yttrium chromite doping with 2-4 group metal oxides on the corrosion resistance in the air at 1300 C during 5 hours and in sodium chloride and sulfate melts at 900 C during 20 hours is investigated. A notable increase of corrosion resistance is achieved under complex doping with zirconium and magnesium oxides in a quantity, close to solubility in yttrium oxide and solubility by aluminium oxide. Doping with calcium and strontium oxides in the quantities, dose to solubility in yttrium oxide does not produce any notable effect, and at higher concentrations it reduces the corrosion resistance in media indicated. Refs. 8, refs. 2, tabs. 1

Effects of calcium and magnesium on strontium distribution coefficients

Science.gov (United States)

Bunde, R.L.; Rosentreter, J.J.; Liszewski, M.J.; Hemming, C.H.; Welhan, J.

1997-01-01

The effects of calcium and magnesium on the distribution of strontium between a surficial sediment and simulated wastewater solutions were measured as part of an investigation to determine strontium transport properties of surficial sediment at the Idaho National Engineering Laboratory (INEL), Idaho. The investigation was conducted by the U.S. Geological Survey and Idaho State University, in cooperation with the U.S. Department of Energy. Batch experimental techniques were used to determine strontium linear sorption isotherms and distribution coefficients (K(d)'s) using simulated wastewater solutions prepared at pH 8.0??0.1 with variable concentrations of calcium and magnesium. Strontium linear sorption isotherm K(d)'s ranged from 12??1 to 85??3 ml/g, increasing as the concentration of calcium and magnesium decreased. The concentration of sorbed strontium and the percentage of strontium retained by the sediment were correlated to aqueous concentrations of strontium, calcium, and magnesium. The effect of these cation concentrations on strontium sorption was quantified using multivariate least-squares regression techniques. Analysis of data from these experiments indicates that increased concentrations of calcium and magnesium in wastewater discharged to waste disposal ponds at the INEL increases the availability of strontium for transport beneath the ponds by decreasing strontium sorption to the surficial sediment.

Hanford waste encapsulation: strontium and cesium

International Nuclear Information System (INIS)

Jackson, R.R.

1976-06-01

The strontium and cesium fractions separated from high radiation level wastes at Hanford are converted to the solid strontium fluoride and cesium chloride salts, doubly encapsulated, and stored underwater in the Waste Encapsulation and Storage Facility (WESF). A capsule contains approximately 70,000 Ci of 137 Cs or 70,000 to 140,000 Ci of 90 Sr. Materials for fabrication of process equipment and capsules must withstand a combination of corrosive chemicals, high radiation dosages and frequently, elevated temperatures. The two metals selected for capsules, Hastelloy C-276 for strontium fluoride and 316-L stainless steel for cesium chloride, are adequate for prolonged containment. Additional materials studies are being done both for licensing strontium fluoride as source material and for second generation process equipment

Superconductivity in doped semiconductors

Energy Technology Data Exchange (ETDEWEB)

Bustarret, E., E-mail: Etienne.bustarret@neel.cnrs.fr

2015-07-15

A historical survey of the main normal and superconducting state properties of several semiconductors doped into superconductivity is proposed. This class of materials includes selenides, tellurides, oxides and column-IV semiconductors. Most of the experimental data point to a weak coupling pairing mechanism, probably phonon-mediated in the case of diamond, but probably not in the case of strontium titanate, these being the most intensively studied materials over the last decade. Despite promising theoretical predictions based on a conventional mechanism, the occurrence of critical temperatures significantly higher than 10 K has not been yet verified. However, the class provides an enticing playground for testing theories and devices alike.

Distribution of strontium in milk component

International Nuclear Information System (INIS)

Rosskopfova, O.; Galambos, M.; Rajec, P.

2011-01-01

The distribution of strontium between the milk components, i.e., serum, casein micelles, whey and hydroxyapatite was determined. The sorption on hydroxyapatite was investigated using batch method and radiotracer technique. The aqueous phase comprised of either milk or whey. The sorption of strontium on hydroxyapatite depended on the method of its preparation and on the composition of the aqueous phase. The sorption of strontium was increased with an increase of pH. The presence of citrate species resulted in decrease of the sorption of strontium on hydroxyapatite. The sorption of 85 Sr on hydroxyapatite decreased with the increasing concentration of Ca 2+ ions. Addition of Ca 2+ ions to milk resulted in milk pH decrease. The decrease in pH value after calcium addition to milk is related to exchanges between added calcium and micellar H + . The average value of strontium sorption on casein micelles in milk with presence of hydroxyapatite was (47.3 ± 5.6) %. The average value of sorption of 85 Sr on casein micelles in milk without the addition of hydroxyapatite was (68.9 ± 2.2) %. (author)

Strontium metabolism and mechanism of interaction with mineralized tissues

International Nuclear Information System (INIS)

Wadkins, C.L.; Fu Peng, C

1981-01-01

This paper examines the administration of strontium to birds and mammals which results in limited incorporation into skeletal tissue, depressed intestinal calcium absorption, and development of rachitic bone lesions. Comparison of radiostrontium and radiocalcium incorporation by intact animals reveals discrimination against strontium in favor of calcium. Comparison of the Sr 85 - Ca 2+ and Ca 45 - Ca 2+ exchange reveals discrimination against strontium in favor of calcium. Thus, this system manifests product specificity, strontium inhibition, strontium exchange, and discrimination observed with intact animals

Uptake behavior of titanium molybdophosphate for cesium and strontium

International Nuclear Information System (INIS)

Yavari, R.; Ahmadi, S.J.; Huang, Y.D.

2010-01-01

This study investigates uptake of cesium and strontium from aqueous solution similar to nuclear waste on three samples of titanium molybdophosphate (TMP) synthesized under various conditions. Effects of concentration of sodium nitrate, pH and contact time on the uptake of cesium and strontium have been studied by bath method. The results showed that TMP has high affinity toward cesium and strontium at pH > 2 and relatively low concentration of sodium nitrate. Kinetic data indicated that cesium uptake process to achieve equilibrium was faster than strontium. Cesium and strontium breakthrough curves were examined at 25 deg C using column packed with H 3 O + form of TMP and breakthrough curves showed symmetrical S-shaped profiles. At the same time, the calculated breakthrough capacity for cesium was higher than strontium. The results of desorption studies showed that over 99% of cesium and strontium was washed out of column by using 4 M NH 4 Cl solution. This study suggests that TMP can have great potential applications for the removal of strontium and specially cesium from nuclear waste solution. (author)

Calcium phosphate cements with strontium halides as radiopacifiers.

Science.gov (United States)

López, Alejandro; Montazerolghaem, Maryam; Engqvist, Håkan; Ott, Marjam Karlsson; Persson, Cecilia

2014-02-01

High radiopacity is required to monitor the delivery and positioning of injectable implants. Inorganic nonsoluble radiopacifiers are typically used in nondegradable bone cements; however, their usefulness in resorbable cements is limited due to their low solubility. Strontium halides, except strontium fluoride, are ionic water-soluble compounds that possess potential as radiopacifiers. In this study, we compare the radiopacity, mechanical properties, composition, and cytotoxicity of radiopaque brushite cements prepared with strontium fluoride (SrF2 ), strontium chloride (SrCl2 ·6H2 O), strontium bromide (SrBr2 ), or strontium iodide (SrI2 ). Brushite cements containing 10 wt % SrCl2 ·6H2 O, SrBr2 , or SrI2 exhibited equal to or higher radiopacity than commercial radiopaque cements. Furthermore, the brushite crystal lattice in cements that contained the ionic radiopacifiers was larger than in unmodified cements and in cements that contained SrF2 , indicating strontium substitution. Despite the fact that the strontium halides increased the solubility of the cements and affected their mechanical properties, calcium phosphate cements containing SrCl2 ·6H2 O, SrBr2 , and SrI2 showed no significant differences in Saos-2 cell viability and proliferation with respect to the control. Strontium halides: SrCl2 ·6H2 O, SrBr2 , and SrI2 may be potential candidates as radiopacifiers in resorbable biomaterials although their in vivo biocompatibility, when incorporated into injectable implants, is yet to be assessed. Copyright © 2013 Wiley Periodicals, Inc.

Strontium sorption on Savannah River Plant soils

International Nuclear Information System (INIS)

Hoeffner, S.L.

1984-12-01

A laboratory study of strontium-85 sorption was conducted using Savannah River Plant soil and groundwater from the low-level waste burial ground. Systematic variation of soil and water composition indicates that strontium sorption is most strongly a function of pH. Changes in clay content and in K + , Ca 2+ , or Mg 2+ concentrations influence strontium sorption indirectly through the slight pH changes which result. The ions Na + , Cl - , and NO 3 - have no effect. Ferrous ion, added to groundwater to simulate the conditions of water at the bottom of waste trenches, did not account for low strontium sorption observed with some trench waters

Implanted strontium titanate single crystals for energy storage applications

Energy Technology Data Exchange (ETDEWEB)

Stoeber, Max; Cherkouk, Charaf; Walter, Juliane; Strohmeyer, Ralph; Leisegang, Tilmann; Meyer, Dirk Carl [TU Bergakademie, Freiberg (Germany); Schelter, Matthias; Zosel, Jens [Kurt Schwabe Institute, Meinsberg (Germany); Prucnal, Slawomir [Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf (Germany)

2016-07-01

A rapid increase of the demand on efficient energy storage solutions requires new approaches beyond the Li-ion technology. In particular, metal-air batteries as well as solid-state fuel cells offer a great potential for high-energy-density storage devices. Since the efficiency of such devices is significantly limited by the activation of both the oxygen reduction reaction (ORR) and the ionic and electronic conductivities, an adequate porosity as well as a controlled doping are required. The ion implantation is a key technology to achieve this goal. In this work, p- and n-doped strontium titanate (SrTiO{sub 3}) single crystals were used as oxidic materials. The oxygen exchange kinetics as well as the structural changes of the SrTiO{sub 3} crystal surface induced by the ion implantation were investigated. On one hand, the depth profile of dopant concentration and dopant valence state were determined using sputtered X-ray photoelectron spectroscopy (XPS). On the other hand, the overall oxygen exchange kinetic of the implanted SrTiO{sub 3} crystal was quantitatively described by means of coulometric titration using Zirox system (ZIROX GmbH, Germany). Furthermore, the surface morphology of the samples was investigated using atomic force microscopy (AFM).

High performance fuel electrode for a solid oxide electrochemical cell

DEFF Research Database (Denmark)

2013-01-01

perovskite oxides selected from the group consisting of niobium-doped strontium titanate, vanadium-doped strontium titanate, tantalum-doped strontium titanate and mixtures thereof, thereby obtaining a porous anode backbone, (b) sintering the coated electrolyte at a high temperature, such as 1200 DEG C...

Fixation of Radioactive Strontium in Soil

DEFF Research Database (Denmark)

Gregers-Hansen, Birte

1964-01-01

of the other long-lived fission products. Much work2–5 has, therefore, been concerned with the possibility of bringing down the strontium-90 uptake by plants through ploughing or through the addition of lime or fertilizer to the soil. Another factor, the effect of ageing on the availability of strontium, has...... been considered6,7. In general, these methods appear to be of little practical value, except for deep ploughing and the liming of acid soils, both of which will reduce the strontium uptake by a factor of 3–4....

Sorption isolation of strontium from seawater

International Nuclear Information System (INIS)

Avramenko, V.A.; Zheleznov, V.V.; Kaplun, E.V.; Sokol'nitskaya, T.A.; Yukhkam, A.A.

2001-01-01

Sorption isolation of strontium from seawater is considered and prospects of use of selective adsorbents for purification of seawater or liquid radioactive wastes mixed with seawater from 90 Sr are discussed. Comparative analysis of sorptive properties of adsorbents of different nature is done. It is shown that sorption-reagent materials developed by authors can to afford effective separation of 90 Sr from seawater. Possible mechanism of strontium sorption by these adsorbents is considered. The prospect of their use for purification of liquid radioactive wastes from strontium is shown [ru

Determination of mineral radioactive strontium-{sup 90} in urines; Recherche du strontium mineral radioactif {sup 90}Sr dans les urines

Energy Technology Data Exchange (ETDEWEB)

Jeanmaire, L; Jammet, H; Bertrand, S [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1959-07-01

An analytical procedure for radioactive strontium in urine is described. As a first step, a precipitation of calcium oxalate performed on the urine, allows to detect the presence of various fission products and particularly of strontium which is carried by the precipitate. Strontium can then be selectively separated on ion exchange resins. By studying the growth curve of {beta} activity, it is possible to determine the activities which may be attributed to {sup 89}Sr and {sup 90}Sr respectively. (author) [French] Cet article decrit une technique de dosage du strontium radioactif dans les urines. Dans un premier stade, une precipitation d'oxalate de calcium effectuee sur l'urine permet de deceler la presence de differents produits de fission et en particulier du strontium qui est entraine sur ce precipite. Il est possible ensuite de separer selectivement le strontium au moyen de resines echangeuses d'ions. L'examen de le courbe de croissance de l'activite {beta} permet de determiner les activites dues respectivement a {sup 89}Sr et {sup 90}Sr. (auteur)

Strontium-90 migration in Hanford sediments, USA

International Nuclear Information System (INIS)

Steefel, C.I.; Yang, L.; Carroll, S.A.; Roberts, S.; Zachara, J.M.; Yabusaki, S.B.

2005-01-01

Full text of publication follows: Strontium-90 is an important risk-driving contaminant at the Hanford site in eastern Washington, USA. Disposal operations at the Hanford 100-N area released millions of liters of reactor cooling water containing high concentrations of strontium-90 into the vadose zone immediately adjacent to the Columbia River. The effectiveness of pump-and-treat methods for remediation have been questioned, largely because the strontium is strongly sorbed on subsurface sediments via ion exchange reactions and co-precipitation in carbonates. In addition, groundwater monitoring wells show a fluctuating seasonal behavior in which high strontium-90 concentrations correlate with high Columbia River stage, even while average concentrations remain approximately constant. A series of fully saturated reactive transport column experiments have been conducted to investigate the important controls on strontium migration in Hanford groundwater [1]. The experiments were designed to investigate the multicomponent cation exchange behavior of strontium in competition with the cations Na + , Ca +2 , and Mg +2 , the concentration of which differs between river water and groundwater. Reactive transport modeling of the experiments indicates that the Sr +2 selectivity coefficient becomes larger with increasing NaNO 3 concentration, a behavior also shown by the divalent cations Ca +2 and Mg +2 . A new set of column experiments investigates the effect of wetting and drying cycles on strontium- 90 sorption and migration by considering episodic flow in Hanford sediments. In addition, the effect of fluctuating aquifer chemistry as a result of changes in the Columbia River stage on Sr +2 sorption is addressed. Modeling of multicomponent reactive transport under variably saturated conditions is used to interpret the results of the episodic flow/chemistry experiments. [1] Experimental and modeling studies of the migration behavior of strontium in Hanford sediments, USA. C

Energetics of magnesium, strontium, and barium doped lanthanum gallate perovskites

International Nuclear Information System (INIS)

Cheng Jihong; Navrotsky, Alexandra

2004-01-01

LaGaO 3 perovskites doped with Sr or Ba at the La site and Mg at the Ga site were prepared by solid-state reaction or sol-gel method and characterized. Enthalpies of formation from constituent oxides at 298 K were determined by high-temperature oxide melt solution calorimetry. Energetic trends are discussed in terms of defect chemistry. As oxygen deficiency increases, formation enthalpies define three trends, LaGa 1-y Mg y O 3-δ (LGM), La 1-x Sr x Ga 1-y Mg y O 3-δ (LSGM), and La 1-x Ba x Ga 1-y Mg y O 3-δ (LBGM). They become less exothermic with increasing doping, suggesting a dominant destabilization effect from oxygen vacancies. The endothermic enthalpy of vacancy formation is 275±37, 166±18 and 138±12 kJ/mol of V O ·· for LGM, LBGM and LSGM, respectively. Tolerance factor and ion size mismatch also affect enthalpies. In terms of energetics, Sr is the best dopant for the La site and Mg for the Ga site, supporting earlier studies, including oxygen ion conductivity and computer modeling

Energetics of magnesium, strontium, and barium doped lanthanum gallate perovskites

Science.gov (United States)

Cheng, Jihong; Navrotsky, Alexandra

2004-01-01

LaGaO 3 perovskites doped with Sr or Ba at the La site and Mg at the Ga site were prepared by solid-state reaction or sol-gel method and characterized. Enthalpies of formation from constituent oxides at 298 K were determined by high-temperature oxide melt solution calorimetry. Energetic trends are discussed in terms of defect chemistry. As oxygen deficiency increases, formation enthalpies define three trends, LaGa 1- yMg yO 3- δ (LGM), La 1- xSr xGa 1- yMg yO 3- δ (LSGM), and La 1- xBa xGa 1- yMg yO 3- δ (LBGM). They become less exothermic with increasing doping, suggesting a dominant destabilization effect from oxygen vacancies. The endothermic enthalpy of vacancy formation is 275±37, 166±18 and 138±12 kJ/mol of VO·· for LGM, LBGM and LSGM, respectively. Tolerance factor and ion size mismatch also affect enthalpies. In terms of energetics, Sr is the best dopant for the La site and Mg for the Ga site, supporting earlier studies, including oxygen ion conductivity and computer modeling.

Structural, optical, photoluminescence and photocatalytic assessment of Sr-doped ZnO nanoparticles

International Nuclear Information System (INIS)

Pradeev Raj, K.; Sadaiyandi, K.; Kennedy, A.; Thamizselvi, R.

2016-01-01

ZnO nanoparticles (NPs) and Strontium doped ZnO nanoparticles (2–6 mol %) (SZ-NPs) were synthesized via Co-precipitation method. Synthesized samples were investigated by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Elemental dispersive spectroscopy (EDS), UV–visible, and Photoluminescence (PL) spectroscopy. Photocatalytic studies for Rhodamine B (RhB) dye in aqueous solution under UV–Vis radiation. XRD analysis confirms that all the samples have hexagonal wurtzite structure. The average crystallite size of the nanoparticles was in the range of 29–51 nm. From the Williamson –Hall (W-H) plot, a positive slope is inferred for pure and SZ-NPs, confirming the presence of tensile strain. SEM images reveal the synthesized NPs are in nanometer range with various shapes are observed. The presence of strontium (Sr) in the host lattice was confirmed by EDS spectroscopy. The optical analysis shows the absorption decreases on doping and shifts slightly towards the longer wavelength region. The band gap energy (Eg) decreases (3.32–3.03 eV) with the increase of Sr dopant concentration. The photoluminescence (PL) spectrum reveals the UV emission is strong near the band-edge region (NBE) (392 nm) and intrinsic defects resulted in series of Vis emissions around 400–560 nm. Kinetic studies on RhB dye indicates the degradation rate has increased with dopant concentration. The improved photocatalytic activity is observed due to the efficient charge separation, improved visible light absorption, inhibition of the electron-hole pair's recombination and better adsorptive of RhB dye molecule on the surface of SZ-NPs. Moreover, the reduction in the total organic carbon (TOC) results reveals the improved photocatalytic activity of strontium doped ZnO NPs. - Highlights: • Effective synthesis of ZnO and Sr−ZnO nanoparticles by co-precipitation method. • Samples were characterized by XRD, SEM, EDS, UV–Vis and PL technique. • Higher optical absorption and

Structural, optical, photoluminescence and photocatalytic assessment of Sr-doped ZnO nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Pradeev Raj, K., E-mail: pradeevraj@gmail.com [Research and Development Centre, Bharathiar University, Coimbatore, 641 046, Tamilnadu (India); Department of Physics, CSI College of Engineering, Ooty, The Nilgiris, 643 215, Tamil Nadu (India); Sadaiyandi, K. [Department of Physics, Alagappa Government Arts College, Karaikudi, Sivagangai, 630 003, Tamil Nadu (India); Kennedy, A. [Department of Physics, CSI College of Engineering, Ooty, The Nilgiris, 643 215, Tamil Nadu (India); Thamizselvi, R. [Department of Chemistry, L.R.G. Govt Arts College for Women, Tirupur, 641604, Tamil Nadu (India)

2016-11-01

ZnO nanoparticles (NPs) and Strontium doped ZnO nanoparticles (2–6 mol %) (SZ-NPs) were synthesized via Co-precipitation method. Synthesized samples were investigated by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Elemental dispersive spectroscopy (EDS), UV–visible, and Photoluminescence (PL) spectroscopy. Photocatalytic studies for Rhodamine B (RhB) dye in aqueous solution under UV–Vis radiation. XRD analysis confirms that all the samples have hexagonal wurtzite structure. The average crystallite size of the nanoparticles was in the range of 29–51 nm. From the Williamson –Hall (W-H) plot, a positive slope is inferred for pure and SZ-NPs, confirming the presence of tensile strain. SEM images reveal the synthesized NPs are in nanometer range with various shapes are observed. The presence of strontium (Sr) in the host lattice was confirmed by EDS spectroscopy. The optical analysis shows the absorption decreases on doping and shifts slightly towards the longer wavelength region. The band gap energy (Eg) decreases (3.32–3.03 eV) with the increase of Sr dopant concentration. The photoluminescence (PL) spectrum reveals the UV emission is strong near the band-edge region (NBE) (392 nm) and intrinsic defects resulted in series of Vis emissions around 400–560 nm. Kinetic studies on RhB dye indicates the degradation rate has increased with dopant concentration. The improved photocatalytic activity is observed due to the efficient charge separation, improved visible light absorption, inhibition of the electron-hole pair's recombination and better adsorptive of RhB dye molecule on the surface of SZ-NPs. Moreover, the reduction in the total organic carbon (TOC) results reveals the improved photocatalytic activity of strontium doped ZnO NPs. - Highlights: • Effective synthesis of ZnO and Sr−ZnO nanoparticles by co-precipitation method. • Samples were characterized by XRD, SEM, EDS, UV–Vis and PL technique. • Higher optical absorption

Calcium versus strontium handling by the heart muscle.

Science.gov (United States)

Hendrych, Michal; Olejnickova, Veronika; Novakova, Marie

2016-01-01

Calcium plays a crucial role in numerous processes in living systems, from both intracellular and intercellular signalling to blood clotting. Calcium can be replaced by strontium in various intracellular processes due to high level of their similarity and strontium thus may serve as a valuable tool for different experimental studies. On the other hand, strontium is also used in clinical medicine and is commonly taken to the human body with food and water. The negative cardiac side effects of strontium therapy of osteoporosis and bone metastases are well known, but still not fully explained. This fact explains enhanced interest in this element and its impact on human body. This article reviews effects of calcium and strontium on several biochemical and physiological processes, with special emphasis on cardiac muscle.

Study of the auto-irradiation effects in apatites structure materials

International Nuclear Information System (INIS)

Soulet, St.

2000-11-01

decreases rapidly with the increase of SiO 4 /PO 4 ratio; this is in agreement with the conclusions of the study with natural analogous. It decreases also when the fluor anion is replaced by an hydroxyl group. With the current knowledge, the annealing by alpha seems to be an unique property of the apatitic structure. In order to model the behavior of ceramics when they are doped with actinides, it has been established, with defects creation and recovery velocities, the differential equation of the disorder evolution in terms of the storage or disposal time. The resolution of this equation in the case of the phospho-calcic fluoro-apatite and the fluoro-apatite with one silicate allows to conclude that these two potential matrices will probably keep their crystal structure during the storage or the disposal. (O.M.)

Study of the auto-irradiation effects in apatites structure materials; Etude des effets d'auto-irradiation dans des materiaux a structure apatitique

Energy Technology Data Exchange (ETDEWEB)

Soulet, St

2000-11-15

decreases rapidly with the increase of SiO{sub 4}/PO{sub 4} ratio; this is in agreement with the conclusions of the study with natural analogous. It decreases also when the fluor anion is replaced by an hydroxyl group. With the current knowledge, the annealing by alpha seems to be an unique property of the apatitic structure. In order to model the behavior of ceramics when they are doped with actinides, it has been established, with defects creation and recovery velocities, the differential equation of the disorder evolution in terms of the storage or disposal time. The resolution of this equation in the case of the phospho-calcic fluoro-apatite and the fluoro-apatite with one silicate allows to conclude that these two potential matrices will probably keep their crystal structure during the storage or the disposal. (O.M.)

Kinetics of strontium sorption in calcium phosphate

International Nuclear Information System (INIS)

Bacic, S.; Komarov, V.F.; Vukovic, Z.

1989-01-01

Kinetics of strontium sorption by highly dispersed solids: tricalcium phosphate (Ca 3 (PO 4 ) 2 , TCP) and hydroxyapatite (Ca 5 (PO 4 ) 3 )H, HAP) were investigated. Analysis of sorption data was made taking into consideration composition and morphology of ultra micro particles. Conclusion is that the isomorphous strontium impurity is structurally sensitive element for calcium phosphate. It was determined that the beginning of strontium desorption corresponds to the beginning of transformation of the TCP - HAP (author)

Measurement of strontium 90 in the rain fall-out

International Nuclear Information System (INIS)

Suratman; Soedyartomo; Suhartono.

1976-01-01

The procedure of radioactivity measurement of strontium 90 in the rain fallout as well as the measurement of the fallout gross beta activity have been studied. In the preliminary study strontium 90 is separated from other cations especially fission products by fuming nitric acid, and radioactivity measurement is carried out in the form of strontium oxalate. Data of radioactivity measurement of strontium 90 and the gross beta activity in the fallout are given. (author)

The coprecipitation of strontium with hydroxyapatite

International Nuclear Information System (INIS)

Fujino, Osamu

1975-01-01

The distribution behavior of the strontium ion between hydroxyapatite and the parent solution was investigated. The hydroxyapatite was formed by the extremely slow addition of diammonium hydrogenphosphate to solutions of calcium and strontium nitrate buffered with ethylenediamine at 80 0 C. The precipitate yielded a typical X-ray diffraction pattern of hydroxyapatite and had a composition in which the Ca/P molar ratio was 1.67 at pH 6.80. The strontium ion was coprecipitated in the apatite, obeying the Doerner and Hoskins logarithnmic distribution law. The distribution coefficient was scarcely affected by the strontium concentration on the pH value in the parent solution, and had a value of 0.26+-0.02 at 80 0 C. On the other hand, the apparent distribution coefficient was a little affected by such organic anions as acetate, citrate, lactate, glycinate, and glutamate ions. The lattice constants of the precipitates prepared in the research were measured in order to confirm the formation of the solid solutions. (auth.)

Conductivity of A- and B-site doped LaAlO3, LaGaO3, LaScO3 and LaInO3 perovskites

DEFF Research Database (Denmark)

Lybye, D.; Poulsen, F.W.; Mogensen, Mogens Bjerg

2000-01-01

The conductivity of the materials LaAlO3, LaGaO3, LaScO3 and LaInO3 all doped with 10% strontium on the A-site and 10% magnesium at the B-site has been measured at different temperatures and oxygen partial pressures. The doped LaGaO3 is found to be an almost pure ionic conductor with a conductivi...

Defect and electrical transport properties of Nb-doped SrTiO₃

DEFF Research Database (Denmark)

Blennow Tullmar, Peter; Hagen, Anke; Kammer Hansen, Kent

2008-01-01

analyzed with SEM, XRD, TGA, and XANES. The electrical conductivity of Nb-doped strontium titanate (Sr0.94Ti0.9Nb0.1O3 - sintered in 9% H-2/N-2 at 1400 degrees C for 12 h) decreased with increasing temperature and showed a phonon scattering conduction mechanism with (sigma>120 S/cm at 1000 degrees C (in 9...

Thermal Transport and Phonon Hydrodynamics in Strontium Titanate

Science.gov (United States)

Martelli, Valentina; Jiménez, Julio Larrea; Continentino, Mucio; Baggio-Saitovitch, Elisa; Behnia, Kamran

2018-03-01

We present a study of thermal conductivity, κ , in undoped and doped strontium titanate in a wide temperature range (2-400 K) and detecting different regimes of heat flow. In undoped SrTiO3 , κ evolves faster than cubic with temperature below its peak and in a narrow temperature window. Such behavior, previously observed in a handful of solids, has been attributed to a Poiseuille flow of phonons, expected to arise when momentum-conserving scattering events outweigh momentum-degrading ones. The effect disappears in the presence of dopants. In SrTi1 -xNbx O3 , a significant reduction in lattice thermal conductivity starts below the temperature at which the average inter-dopant distance and the thermal wavelength of acoustic phonons become comparable. In the high-temperature regime, thermal diffusivity becomes proportional to the inverse of temperature, with a prefactor set by sound velocity and Planckian time (τp=(ℏ/kBT ) ).

Ion exchange of strontium on synthetic hydroxyapatite

International Nuclear Information System (INIS)

Lazic, S.; Vukovic, Z.

1991-01-01

Adsorption of strontium ions on synthetic hydroxyapatite was examined using both batch and column methods. The apatite was prepared from aqueous solutions and characterized by standard analytical methods. The sample obtained had characteristics of well crystallized stoichiometric hydroxyapatite. The experimental data for sorption of strontium can be very well fitted with Langmuir's adsorption isotherm. It was found that sorption occurs by an ion exchange reaction between strontium ions in solution and calcium ions in apatite. (author) 14 refs.; 5 figs.; 1 tab

Impact of ZnO substitution on magnetic response and microwave absorption capability of strontium-natural nanoferrites

Directory of Open Access Journals (Sweden)

W. Widanarto

2015-01-01

Full Text Available Ferrite being a compound derived from iron oxides including magnetite and hematite possesses similar properties as ceramics which are hard and brittle. Certainly, the mounting demand for electronics has been a major factor driving the exponential growth of ferrite based materials. ZnO doped strontium-natural nanoferrites of composition (80 − xFe2O3:xZnO:20SrCO3, where x = 0, 10, 20 mol% are synthesized and sintered via the solid state reaction scheme. Samples are characterized by SEM, XRD, VSM, and VNA measurements to determine the impact of ZnO contents’ variation on the surface morphology, structure, magnetic and microwave absorption properties. The Nicolson–Ross–Weir method is applied to evaluate samples’ reflection loss. The average grain size of the strontium ferrite is found to reduce with the increase in ZnO concentration. Materials sintered at 1100 °C without ZnO incorporation are composed of hexagonal SrFe12O19. Meanwhile, the addition of ZnO produces cubic ZnFe2O4 and SrFeO2 phases. Insertion of ZnO results in reduction of magnetic parameters and reflection loss. Furthermore, the anisotropy magnetic field of strontium natural ferrites displays a rapid drop from 350 kA/m to 79.6 kA/m with the increase in ZnO. Strontium ferrite containing 20 mol% of ZnO exhibits superior microwave absorption with reflection loss within −45 dB to −55.94 dB in the frequency range of 7–13 GHz. This facilely synthesized a new class of materials which is believed to be economically promising for microwave absorption applications in the GHz range.

Synthesis and characterization of strontium molybdate doped with copper, cobalt and zinc for purposes photocatalytic; Sintese e caracterizacao do molibdato de estroncio dopado com cobre, cobalto e zinco para fins fotocataliticos

Energy Technology Data Exchange (ETDEWEB)

Dutra, F.B.; Silva, M.M.S.; Moriyama, A.L.L.; Souza, C.P., E-mail: faby_qui@hotmail.com [Universidade Federal do Rio Grande do Norte (LAMNRC/UFRN), Natal, RN (Brazil). Lab. de Materiais Nanoestruturados e Reatores Catalicos

2016-07-01

The broad concerns of contemporary society with environmental problems requires legislation and more effective techniques for wastewater treatment. In recent years, ceramic materials that have properties such as high melting points and high stability have been receiving great emphasis in several studies in particular heterogeneous photocatalysis, rapid and efficient method for the complete mineralization of contaminants. In this context, the present work deals with the synthesis and characterization of molybdate Strontium (SrMoO4) doped with copper, cobalt and zinc for the purpose of photocatalytic studies. The compounds were synthesized by complexation method EDTA / Citrate basic medium. The powders were characterized by Thermogravimetric Analysis (TG), X-Ray Diffraction (XRD), Particle size distribution by laser diffraction, Spectroscopy in the UV-Visible region, Energy Dispersive Spectroscopy (EDS) and Scanning Electron Microscopy (SEM), showing promising results as the crystalline phase of development and potential uses for the purpose of heterogeneous photocatalysis. (author)

Fabrication and characterization of strontium incorporated 3-D bioactive glass scaffolds for bone tissue from biosilica

Energy Technology Data Exchange (ETDEWEB)

Özarslan, Ali Can, E-mail: alicanozarslan@gmail.com; Yücel, Sevil, E-mail: syucel@yildiz.edu.tr

2016-11-01

Bioactive glass scaffolds that contain silica are high viable biomaterials as bone supporters for bone tissue engineering due to their bioactive behaviour in simulated body fluid (SBF). In the human body, these materials help inorganic bone structure formation due to a combination of the particular ratio of elements such as silicon (Si), calcium (Ca), sodium (Na) and phosphorus (P), and the doping of strontium (Sr) into the scaffold structure increases their bioactive behaviour. In this study, bioactive glass scaffolds were produced by using rice hull ash (RHA) silica and commercial silica based bioactive glasses. The structural properties of scaffolds such as pore size, porosity and also the bioactive behaviour were investigated. The results showed that undoped and Sr-doped RHA silica-based bioactive glass scaffolds have better bioactivity than that of commercial silica based bioactive glass scaffolds. Moreover, undoped and Sr-doped RHA silica-based bioactive glass scaffolds will be able to be used instead of undoped and Sr-doped commercial silica based bioactive glass scaffolds for bone regeneration applications. Scaffolds that are produced from undoped or Sr-doped RHA silica have high potential to form new bone for bone defects in tissue engineering. - Highlights: • Production of 3-D bioactive glass scaffolds from different silica sources • The effect of biosilica from rice hull ash on the bioactive glass scaffold • Sr additive impact on the bioactivity and biodegradability properties of scaffolds.

A combined cesium-strontium extraction/recovery process

International Nuclear Information System (INIS)

Horwitz, E.P.; Dietz, M.L.; Jensen, M.P.

1996-01-01

A new solvent extraction process for the simultaneous extraction of cesium and strontium from acidic nitrate media is described. This process uses a solvent formulation comprised of 0.05 M di-t-butylcyclohexano-18-crown-6 (DtBuCH18C6), 0.1 M Crown 100' (a proprietary, cesium-selective derivative of dibenzo-18-crown-6), 1.2 M tributyl phosphate (TBP), and 5% (v/v) lauryl nitrile in an isoparaffinic hydrocarbon diluent. Distribution ratios for cesium and strontium from 4 M nitric acid are 4.13 and 3.46, respectively. A benchtop batch countercurrent extraction experiment indicates that >98% of the cesium and strontium initially present in the feed solution can be removed in only four extraction stages. Through proper choice of extraction and strip conditions, extracted cesium and strontium can be recovered either together or individually

Materials system for intermediate temperature solid oxide fuel cells based on doped lanthanum-gallate electrolyte

Science.gov (United States)

Gong, Wenquan

2005-07-01

The objective of this work was to identify a materials system for intermediate temperature solid oxide fuel cells (IT-SOFCs). Towards this goal, alternating current complex impedance spectroscopy was employed as a tool to study electrode polarization effects in symmetrical cells employing strontium and magnesium doped lanthanum gallate (LSGM) electrolyte. Several cathode materials were investigated including strontium doped lanthanum manganite (LSM), Strontium and iron doped lanthanum cobaltate (LSCF), LSM-LSGM, and LSCF-LSGM composites. Investigated Anode materials included nickel-gadolinium or lanthanum doped cerium oxide (Ni-GDC, or Ni-LDC) composites. The ohmic and the polarization resistances of the symmetrical cells were obtained as a function of temperature, time, thickness, and the composition of the electrodes. Based on these studies, the single phase LSM electrode had the highest polarization resistance among the cathode materials. The mixed-conducting LSCF electrode had polarization resistance orders of magnitude lower than that of the LSM-LSGM composite electrodes. Although incorporating LSGM in the LSCF electrode did not reduce the cell polarization resistance significantly, it could reduce the thermal expansion coefficient mismatch between the LSCF electrodes and LSGM electrolyte. Moreover, the polarization resistance of the LSCF electrode decreased asymptotically as the electrode thickness was increased thus suggesting that the electrode thickness needed not be thicker than this asymptotic limit. On the anode side of the IT-SOFC, Ni reacted with LSGM electrolyte, and lanthanum diffusion occurred from the LSGM electrolyte to the GDC barrier layer, which was between the LSGM electrolyte and the Ni-composite anode. However, LDC served as an effective barrier layer. Ni-LDC (70 v% Ni) anode had the largest polarization resistance, while all other anode materials, i.e. Ni-LDC (50 v% Ni), Ni-GDC (70 v% NO, and Ni-GDC (50 v% Ni), had similar polarization

Strontium clusters: electronic and geometry shell effects

DEFF Research Database (Denmark)

Lyalin, Andrey G.; Solov'yov, Ilia; Solov'yov, Andrey V.

2008-01-01

charged strontium clusters consisting of up to 14 atoms, average bonding distances, electronic shell closures, binding energies per atom, and spectra of the density of electronic states (DOS). It is demonstrated that the size-evolution of structural and electronic properties of strontium clusters...... is governed by an interplay of the electronic and geometry shell closures. Influence of the electronic shell effects on structural rearrangements can lead to violation of the icosahedral growth motif of strontium clusters. It is shown that the excessive charge essentially affects the optimized geometry...

Leaching of strontium sulfide from produced clinker in conversion furnace

International Nuclear Information System (INIS)

Ghorbanian, S. A.; Salehpour, A. R.; Radpour, S. R.

2009-01-01

Iran is rich in mineral resources one of which is mineral Celestine. Basing on current estimations, the capacity of mineral Celestine is over two million tons, 75-95% of which is strontium sulfate. However; in industries such as Color cathode Ray Tubes, pyrochemical processes, ceramics, paint production, zinc purification processes; strontium sulfate is not a direct feed, rather it is largely consumed in the form of strontium carbonate. Two conventional methods are used to produce strontium carbonate from the sulfate; that is direct reaction and black ash methods. Strontium sulfide, as an intermediate component has a key role in black ash process including strontium sulfate reduction by coke, hence producing and leaching the strontium sulfide by hot water. Finally the reaction of strontium sulfate with sodium carbonate lead to strontium carbonate. In this paper, a system was designed to analyze and optimize the process parameters of strontium sulfide production which is less expensive and available solvent in water. Fundamentally, when strontium sulfide becomes in contact with strontium sulfate; Sr(SH) 2 , and Sr(OH) 2 , are produced. The solubility of strontium sulfide depends on water temperature and the maximum solubility achieved at 90 d egree C . The results showed that in the experimental scale, at water to SrS ratio of 6; they sediment for 45 minutes at 95 d egree C in five operational stages; the separation of 95 and 97.1 percent of imported SrS is possible in effluent of fourth and fifth stages, respectively. Thus; four leaching stages could be recommended for pilot scale plants. Also, the results show that at water to SrS ratio of 8, 40 minutes sedimentation at 85-95 d egree C in one operational stage, the separation of 95 percent separation of inputted SrS, is possible. Solvent leaching process is continued till no smell of sulfur components is felt. It could be used as a key role to determine the number of leaching stages in experiments. Finally, the

Magnetic and microwave absorption properties of rare earth ions (Sm{sup 3+}, Er{sup 3+}) doped strontium ferrite and its nanocomposites with polypyrrole

Energy Technology Data Exchange (ETDEWEB)

Luo, Juhua, E-mail: luojuhua@163.com [School of Materials Engineering, Yancheng Institute of Technology, Yancheng 224051 (China); Xu, Yang; Mao, Hongkai [School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013 (China)

2015-05-01

M-type strontium ferrite substituted by RE (RE=Sm{sup 3+}, Er{sup 3+}) were prepared via a sol–gel method. Polypyrrole (PPy)/ferrite nanocomposites (with 20 wt% ferrite) were prepared by in situ polymerization method in the presence of ammonium persulfate. Effect of the substituted RE ions on structure, magnetic properties and microwave absorption properties were investigated by X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and vector network analyzer. All XRD patterns show the single phase of strontium hexaferrite without other intermediate phases. The crystallite size of synthesized particle is within the range of 22.2–38.1 nm. The structural in character of the composites were investigated with FT-IR analysis. It shows that the ferrite successfully packed by PPy. TEM photographs show that the particle size had grown up to 50–100 nm after coating with PPy. In the magnetization for the PPy/SrSm{sub 0.3}Fe{sub 11.7}O{sub 19} (SrEr{sub 0.3}Fe{sub 11.7}O{sub 19}) composites, the coercivity (H{sub c}) of the composites both increased compared with the undoped composite while the saturation magnetization (M{sub s}) appeared opposite change with different RE ions. Considering the electromagnetic loss and impedance matching comprehensively, the Er-doped ferrite/PPy composite got the better microwave absorption performance with the maximum RL value of −24.01 dB in 13.8 GHz at 3.0 mm. And its width (<−10 dB) has reached 7.2 GHz which has covered the whole Ku band. - Highlights: • The influence of RE ions on the structure of PPy/SrRE{sub 0.3}Fe{sub 11.7}O{sub 19} is discussed. • The influence of RE ions on the magnetic properties of PPy/SrRE{sub 0.3}Fe{sub 11.7}O{sub 19} is discussed. • The influence of RE ions on electromagnetic losses of PPy/SrRE{sub 0.3}Fe{sub 11.7}O{sub 19} is discussed. • PPy/SrEr{sub 0.3}Fe{sub 11.7}O{sub 19} possessed the excellent absorption property.

Growth of strontium oxalate crystals in agar–agar gel

Indian Academy of Sciences (India)

Growth of strontium oxalate crystals in agar–agar gel. P V DALAL. ∗ and K B SARAF. Postgraduate Department of Physics, Pratap College, Amalner 425 401, India. MS received 16 March 2008; revised 5 April 2010. Abstract. Single crystals of strontium oxalate have been grown by using strontium chloride and oxalic acid in.

Novel Pharmaceutical Strontium Malonate Influence on Calcium and Strontium Adsorption by Dog Femur and by Dog Teeth in a Four-Week Toxicity Study

DEFF Research Database (Denmark)

Raffalt, Anders Christer; Christgau, Stephan; Andersen, Jens Enevold Thaulov

of osteoporosis. As part of this development the compound was administered in doses of 0 (placebo), 300, 1000 and 3000 mg/kg/day to beagle dogs for a period of 4 weeks. We measured the incorporation of strontium in bone, marrow and teeth in this study. Analysis by inductively coupled plasma mass spectrometry...... marginally higher incorporation of strontium suggesting that saturation levels were reached with the lowest dose level. There was no gender difference in strontium incorporation. Correlations of strontium levels with Sr/Ca-ratio and other important biological parameters were investigated....

High temperature superconducting material: Bismuth strontium calcium copper oxide. (Latest citations from the Aerospace database). Published Search

International Nuclear Information System (INIS)

1993-11-01

The bibliography contains citations concerning the development, fabrication, and analysis of a high temperature superconducting material based on bismuth-strontium-calcium-copper-oxides (Bi-Sr-Ca-Cu-O). Topics include the physical properties, structural and compositional analysis, magnetic field and pressure effects, and noble metal dopings of Bi-Sr-Ca-Cu-O based systems. The highest transition temperature recorded to date for this material was 120 degrees Kelvin. Fabrication methods and properties of Bi-Sr-Ca-Cu-O films and ceramics are also considered. (Contains 250 citations and includes a subject term index and title list.)

Effect of ‘A’-site non stoichiometry in strontium doped lanthanum ferrite based solid oxide fuel cell cathodes

Energy Technology Data Exchange (ETDEWEB)

Banerjee, Koyel; Mukhopadhyay, Jayanta, E-mail: jayanta_mu@cgcri.res.in; Barman, Madhurima; Basu, Rajendra N., E-mail: rnbasu@cgcri.res.in

2015-12-15

Highlights: • La{sub 1−x}Sr{sub x}Co{sub y}Fe{sub 1−y}O{sub 3−δ}, x = 0.4; y = 0.2 system varying La-site (0.6–0.54) are studied. • Combustion synthesis technique is used to prepare the powder samples. • Highest electrical conductivity observed with largest A-site deficit composition. • Lowest cathode polarization is found with the same composition (0.02 Ω cm{sup 2}). • Composition with largest A-site deficiency exhibits best performance (2.84 A cm{sup −2}). - Abstract: Effect of A-site non-stoichiometry in strontium doped lanthanum cobalt ferrite (La{sub 1−x}Sr{sub x}Co{sub y}Fe{sub 1−y}O{sub 3−δ}, x = 0.4; y = 0.2) is studied in a systematic manner with variation of ‘A’ site stoichiometry from 1 to 0.94. The perovskite based cathode compositions are synthesized by combustion synthesis. Powder characterizations reveal rhombohedral crystal structure with crystallite size ranging from 29 to 34 nm with minimum lattice spacing of 0.271 nm. Detailed sintering studies along with total DC electrical conductivities are evaluated in the bulk form with variation of sintering temperatures. The electrode polarizations are measured in the symmetric cell configuration by impedance spectroscopy which is found to be the lowest (0.02 Ω cm{sup 2} at 800 °C) for cathode having highest degree of ‘A’-site deficiency. The same cathode composition exhibits a current density of 2.84 A cm{sup −2} (at 0.7 V, 800 °C) in anode-supported single cell. An attempt has been made to correlate the trend of electrical behaviour with increasing ‘A’-site deficiency for such cathode compositions.

Investigation of strontium accumulation on ovariectomized Sprague–Dawley rat tibia by micro-PIXE

Energy Technology Data Exchange (ETDEWEB)

Li, X.; Li, Y. [Institute of Modern Physics, Fudan University, Shanghai 200433 (China); Jin, W. [Institute of Radiation Medicine, Fudan University, Shanghai 200032 (China); Zheng, Y.; Rong, C.; Lyu, H. [Institute of Modern Physics, Fudan University, Shanghai 200433 (China); Shen, H., E-mail: haoshen@fudan.edu.cn [Institute of Modern Physics, Fudan University, Shanghai 200433 (China)

2014-08-01

Strontium ranelate is a newly developed drug effective in osteoporosis treatment by depressing bone resorption and maintaining bone formation. Strontium accumulation and distribution are determined in bones of rat after strontium ranelate administration by using micro-PIXE. The investigated rats are divided into four groups: (A) control, (B) ovariectomized, (C) ovariectomized followed with strontium chloride, (D) ovariectomized followed with strontium ranelate. It was found that strontium ranelate would result in increasing trabecular volume and decreasing bone resorption to treat osteoporosis. There are similar contours of calcium and strontium in two-dimensional images, while the strontium is not evenly distributed in the bone. It supports the conclusion that strontium has an affinity for bone and it is capable of replacing calcium atoms as a part of the strontium mechanism in the osteoporosis treatment. The results related to biochemistry are also discussed.

Strontium-Doped Calcium Phosphate and Hydroxyapatite Granules Promote Different Inflammatory and Bone Remodelling Responses in Normal and Ovariectomised Rats

Science.gov (United States)

Xia, Wei; Emanuelsson, Lena; Norlindh, Birgitta; Omar, Omar; Thomsen, Peter

2013-01-01

The healing of bone defects may be hindered by systemic conditions such as osteoporosis. Calcium phosphates, with or without ion substitutions, may provide advantages for bone augmentation. However, the mechanism of bone formation with these materials is unclear. The aim of this study was to evaluate the healing process in bone defects implanted with hydroxyapatite (HA) or strontium-doped calcium phosphate (SCP) granules, in non-ovariectomised (non-OVX) and ovariectomised (OVX) rats. After 0 (baseline), six and 28d, bone samples were harvested for gene expression analysis, histology and histomorphometry. Tumour necrosis factor-α (TNF-α), at six days, was higher in the HA, in non-OVX and OVX, whereas interleukin-6 (IL-6), at six and 28d, was higher in SCP, but only in non-OVX. Both materials produced a similar expression of the receptor activator of nuclear factor kappa-B ligand (RANKL). Higher expression of osteoclastic markers, calcitonin receptor (CR) and cathepsin K (CatK), were detected in the HA group, irrespective of non-OVX or OVX. The overall bone formation was comparable between HA and SCP, but with topological differences. The bone area was higher in the defect centre of the HA group, mainly in the OVX, and in the defect periphery of the SCP group, in both non-OVX and OVX. It is concluded that HA and SCP granules result in comparable bone formation in trabecular bone defects. As judged by gene expression and histological analyses, the two materials induced different inflammatory and bone remodelling responses. The modulatory effects are associated with differences in the spatial distribution of the newly formed bone. PMID:24376855

P-doped strontium titanate grown using two target pulsed laser deposition for thin film solar cells

Science.gov (United States)

Man, Hamdi

Thin-film solar cells made of Mg-doped SrTiO3 p-type absorbers are promising candidates for clean energy generation. This material shows p-type conductivity and also demonstrates reasonable absorption of light. In addition, p-type SrTiO3 can be deposited as thin films so that the cost can be lower than the competing methods. In this work, Mg-doped SrTiO3 (STO) thin-films were synthesized and analyzed in order to observe their potential to be employed as the base semiconductor in photovoltaic applications. Mg-doped STO thin-films were grown by using pulsed laser deposition (PLD) using a frequency quadrupled Yttrium Aluminum Garnet (YAG) laser and with a substrate that was heated by back surface absorption of infrared (IR) laser light. The samples were characterized using X-ray photoelectron spectroscopy (XPS) and it was observed that Mg atoms were doped successfully in the stoichiometry. Reflection high energy electron diffraction (RHEED) spectroscopy proved that the thin films were polycrystalline. Kelvin Probe work function measurements indicated that the work function of the films were 4.167 eV after annealing. UV/Vis Reflection spectroscopy showed that Mg-doped STO thin-films do not reflect significantly except in the ultraviolet region of the spectrum where the reflection percentage increased up to 80%. Self-doped STO thin-films, Indium Tin Oxide (ITO) thin films and stainless steel foil (SSF) were studied in order to observe their characteristics before employing them in Mg-doped STO based solar cells. Self-doped STO thin films were grown using PLD and the results showed that they are capable of serving as the n-type semiconductor in solar cell applications with oxygen vacancies in their structure and low reflectivity. Indium Tin Oxide thin-films grown by PLD system showed low 25-50 ?/square sheet resistance and very low reflection features. Finally, commercially available stainless steel foil substrates were excellent substrates for the inexpensive growth of

Effect of strontium ranelate on bone mineral: Analysis of nanoscale compositional changes.

Science.gov (United States)

Rossi, André L; Moldovan, Simona; Querido, William; Rossi, Alexandre; Werckmann, Jacques; Ersen, Ovidiu; Farina, Marcos

2014-01-01

Strontium ranelate has been used to prevent bone loss and stimulate bone regeneration. Although strontium may integrate into the bone crystal lattice, the chemical and structural modifications of the bone when strontium interacts with the mineral phase are not completely understood. The objective of this study was to evaluate apatite from the mandibles of rats treated with strontium ranelate in the drinking water and compare its characteristics with those from untreated rats and synthetic apatites with and without strontium. Electron energy loss near edge structures from phosphorus, carbon, calcium and strontium were obtained by electron energy loss spectroscopy in a transmission electron microscope. The strontium signal was detected in the biological and synthetic samples containing strontium. The relative quantification of carbon by analyzing the CK edge at an energy loss of ΔE = 284 eV showed an increase in the number of carbonate groups in the bone mineral of treated rats. A synthetic strontium-containing sample used as control did not exhibit a carbon signal. This study showed physicochemical modifications in the bone mineral at the nanoscale caused by the systemic administration of strontium ranelate. Copyright © 2013 Elsevier Ltd. All rights reserved.

A process for the development of strontium hydroxyapatite

International Nuclear Information System (INIS)

Zahra, N; Fayyaz, M; Iqbal, W; Irfan, M; Alam, S

2014-01-01

A procedure for the preparation of Strontium Hydroxyapatite is adapted to produce high purity and better homogeneity ceramic with good Crystallinity. The strontium substituted bone cement has potential for use in orthopedic surgeries. Ionic Strontium (Sr) in humans shares the same physiological pathway as calcium and can be deposited in the mineral structure of the bone. In the present study, a novel concept of preparing Sr-contained Hydroxyapatite bone cement by using a precipitation method is proposed to get an ideal biomaterial that possesses potential degradability and more excellent pharmacological effect. Chemical analysis, Fourier Transform Infra Red analysis and Thermogravimetric/ Differential Scanning Calorimetric studies were conducted on prepared Strontium Hydroxyapatite sample to characterize the incorporation of 15% Sr 2 + into the crystal lattice of Hydroxyapatite. Strontium was quantitatively incorporated into Hydroxyapatite where its substitution for calcium provoked a linear shift of the infrared absorption bands of the hydroxyl and phosphate groups. Thus, the formation of Sr-HAp was confirmed by Chemical Analysis, FT-IR and TGA/DSC results

A process for the development of strontium hydroxyapatite

Science.gov (United States)

Zahra, N.; Fayyaz, M.; Iqbal, W.; Irfan, M.; Alam, S.

2014-06-01

A procedure for the preparation of Strontium Hydroxyapatite is adapted to produce high purity and better homogeneity ceramic with good Crystallinity. The strontium substituted bone cement has potential for use in orthopedic surgeries. Ionic Strontium (Sr) in humans shares the same physiological pathway as calcium and can be deposited in the mineral structure of the bone. In the present study, a novel concept of preparing Sr-contained Hydroxyapatite bone cement by using a precipitation method is proposed to get an ideal biomaterial that possesses potential degradability and more excellent pharmacological effect. Chemical analysis, Fourier Transform Infra Red analysis and Thermogravimetric/ Differential Scanning Calorimetric studies were conducted on prepared Strontium Hydroxyapatite sample to characterize the incorporation of 15% Sr2+ into the crystal lattice of Hydroxyapatite. Strontium was quantitatively incorporated into Hydroxyapatite where its substitution for calcium provoked a linear shift of the infrared absorption bands of the hydroxyl and phosphate groups. Thus, the formation of Sr-HAp was confirmed by Chemical Analysis, FT-IR and TGA/DSC results.

Method for strontium isolation from high-mineralized water

International Nuclear Information System (INIS)

Evzhanov, Kh.; Andriyasova, G.M.

1983-01-01

A method to isolate strontium from high-mineralized waters containing sodium, magnesium, calcium and strontium chlorides, which differ from the prototype method in a considerable decrease in energy consumption with the preservation of a high degree of Sr, Mg and Ca isolation selectivity, has been suggested. According to the method suggested mineralized waters are treated with alkali (NaOH) in the amount of 95-97% of stoichiometry by magnesium, then after separation of magnesium hydroxide precipitate mother liquor is treated with sodium carbonate in the amount of 50-60% of stoichiometry by calcium. After separation of calcium carbonate precipitate mother liquor is treated with NaOH in the amount of 130-135% of stoichiometry by calcium. After separation of calcium hydroxide precipitate from mother liquor by means of sodium carbonate introduction strontium carbonate is isolated. The degree of strontium extraction in the form of SrCO 3 constitutes 90.5% of its content in the initial solution. The method presented can be used for strontium separation from natural and waste waters

A process for the development of strontium hydroxyapatite

International Nuclear Information System (INIS)

Zahra, N.; Fayyaz, M.; Iqbal, W.; Irfan, M.; Alam, S.

2013-01-01

A procedure for the preparation of Strontium Hydroxyapatite is adapted to produce high purity and better homogeneity ceramic with good Crystallinity. The strontium substituted bone cement has potential for use in orthopedic surgeries. Ionic Strontium (Sr) in humans shares the same physiological pathway as calcium and can be deposited in the mineral structure of the bone. In the present study, a novel concept of preparing Sr-contained Hydroxyapatite bone cement by using a precipitation method is proposed to get an ideal biomaterial that possesses potential degradability and more excellent pharmacological effect. Chemical analysis, Fourier Transform Infra Red analysis and Thermogravimetric/ Differential Scanning Calorimetric studies were conducted on prepared Strontium Hydroxyapatite sample to characterize the incorporation of 15 percentage Sr2+ into the crystal lattice of Hydroxyapatite. Strontium was quantitatively incorporated into Hydroxyapatite where its substitution for calcium provoked a linear shift of the infrared absorption bands of the hydroxyl and phosphate groups. Thus, the formation of Sr-HAp was confirmed by Chemical Analysis, FT-IR and TGA/DSC results. (author)

Infrared characterization of strontium titanate thin films

International Nuclear Information System (INIS)

Almeida, B.G.; Pietka, A.; Mendes, J.A.

2004-01-01

Strontium titanate thin films have been prepared at different oxygen pressures with various post-deposition annealing treatments. The films were deposited by pulsed laser ablation at room temperature on Si(0 0 1) substrates with a silica buffer layer. Infrared reflectance measurements were performed in order to determine relevant film parameters such as layer thicknesses and chemical composition. The infrared reflectance spectra were fitted by using adequate dielectric function forms for each layer. The fitting procedure provided the extraction of the dielectric functions of the strontium titanate film, the silica layer and the substrate. The as-deposited films are found to be amorphous, and their infrared spectra present peaks corresponding to modes with high damping constants. As the annealing time and temperature increases the strontium titanate layer becomes more ordered so that it can be described by its SrTiO 3 bulk mode parameters. Also, the silica layer grows along with the ordering of the strontium titanate film, due to oxidation during annealing

Separation of cesium and strontium with zeolites

Energy Technology Data Exchange (ETDEWEB)

Kanno, T; Hashimoto, H [Tohoku Univ., Sendai (Japan). Research Inst. of Mineral Dressing and Metallurgy

1976-06-01

The basic studies of separation of cesium and strontium were made with specimens of zeolite, which are synthetic zeolites A, X and Y; synthetic mordenite; natural mordenite; and clinoptilolite. Ammonium chloride was used as eluent, because it was considered to be a most appropriate eluent in alkaline chlorides. Cesium was easily eluted from the zeolites A and X by ammonium chloride solution, but it was difficult to elute from the synthetic mordenite, natural mordenite and clinoptilolite by ammonium chloride solution, but it was difficult to elute from the zeolites A and X. The zeolite Y is the only one zeolite among these zeolites from which both of cesium and strontium were easily eluted by ammonium chloride solution. Strontium could be separated from cesium with zeolites by formation of Sr-EDTA chelate at pH above 11. In this process, cesium was only exchanged in zeolite column, but strontium flow out from it.

Separation of cesium and strontium with zeolites

International Nuclear Information System (INIS)

Kanno, Takuji; Hashimoto, Hiroyuki

1976-01-01

The basic studies of separation of cesium and strontium were made with specimens of zeolite, which are synthetic zeolites A, X and Y; synthetic mordenite; natural mordenite; and clinoptilolite. Ammonium chloride was used as eluent, because it was considered to be a most appropriate eluent in alkaline chlorides. Cesium was easily eluted from the zeolites A and X by ammonium chloride solution, but it was difficult to elute from the synthetic mordenite, natural mordenite and clinoptilolite by ammonium chloride solution, but it was difficult to elute from the zeolites A and X. The zeolite Y is the only one zeolite among these zeolites from which both of cesium and strontium were easily eluted by ammonium chloride solution. Strontium could be separated from cesium with zeolites by formation of Sr-EDTA chelate at pH above 11. In this process, cesium was only exchanged in zeolite column, but strontium flow out from it. (auth.)

Effects of Nb and Sr doping on crystal structure of epitaxial BaTiO3 thin films on MgO substrates

International Nuclear Information System (INIS)

Kim, Yongsam; Chen, Chunhua; Saiki, Atsushi; Wakiya, Naoki; Shinozaki, Kazuo; Mizutani, Nobuyasu

2002-01-01

Niobium (Nb) and strontium (Sr) doped barium titanate (BT) films were deposited by radio frequency (RF) magnetron sputtering with Nb and Sr doped BT ceramic targets, respectively. The effect of Nb and Sr doping on the crystal structure of epitaxial BaTiO 3 thin films on MgO substrates was investigated. The crystal structure of the films was examined using the reciprocal space mapping measurement. All the films exhibit a cube-on-cube relation with respect to the substrates. As the amount of doped Sr increased, both of the in-plane and out-of-plane lattice constants of Sr doped BT films slowly approached the BT bulk values. On the other hand, the lattice constants of Nb doped BT films were rapidly coming close to the bulk values. These indicated that the lattices of doped BT films were relaxed as the amount of doped elements increased. In addition, Nb doping had greater influence on the relaxation of the films than Sr doping for the same content of dopant. (author)

Strontium 90 in silts of the Dnieper cascade water reservoirs

International Nuclear Information System (INIS)

Romanenko, V.D.; Kuz'menko, M.I.; Matvienko, L.P.; Klenus, V.G.; Nasvit, O.I.

1989-01-01

The change of strontium-90 content in water and silts of the Dnieper cascade water reservoirs was analyzed. It was shown, that decrease of strontium-90 content in water in time connected basically with ion exchange adsorption of strontium-90 by residues. A high sorption ability of residues made it possible for radioisotopes to reduce sharply their concentration along depth of soils. The highest concentration of radioisotopes was in the upper layers, enriched by silt. It was ascertained, that strontium-90 migration along depth of residues took place rapidly in the Kiev's water reservoir. Down the cascade strontium-90 content reduced in lower layers of residues as well as in upper layers. 4 tabs

Surface modification of strontium-doped porous bioactive ceramic scaffolds via poly(DOPA) coating and immobilizing silk fibroin for excellent angiogenic and osteogenic properties.

Science.gov (United States)

Wang, Xu; Gu, Zhipeng; Jiang, Bo; Li, Li; Yu, Xixun

2016-04-01

For bioceramic scaffolds employed in clinical applications, excellent bioactivity and tenacity were of great importance. Modifying inorganic SCPP scaffolds with biological macromolecules could obviously improve its bioactivity and eliminate its palpable brittleness. However, it was hard to execute directly due to extremely bad interfacial compatibility between them. In this research, dopamine (DOPA) was introduced onto strontium-doped calcium polyphosphate (SCPP) scaffolds, subsequently the preliminary material was successfully further modified by silk fibroin (SF). SCPP/D/SF possessed suitable biomechanical properties, ability to stimulate angiogenic factor secretion and excellent biocompatibility. Biomechanical examination demonstrated that SCPP/D/SF scaffolds yielded better compressive strength because of improved interfacial compatibility. MTT assay and CLSM observation showed that SCPP/D/SF scaffolds had good cytocompatibility and presented better inducing-cell-migration potential than pure SCPP scaffolds. Meanwhile, its ability to stimulate angiogenic factor secretion was measured through the ELISA assay and immunohistological analysis in vitro and in vivo respectively. The results revealed, superior to SCPP, SCPP/D/SF could effectively promote VEGF and bFGF expression, possibly leading to enhancing angiogenesis and osteogenesis. In a word, SCPP/D/SF could serve as a potential bone tissue engineering scaffold for comparable biomechanical properties and excellent bioactivity. It provided a novel idea for modification of inorganic materials to prepare promising bone tissue engineering scaffolds with the ability to accelerate bone regeneration and vascularization.

Reduced-graphene-oxide-and-strontium-titanate-based double ...

Indian Academy of Sciences (India)

GO)/strontium titanate were pre- ... R-GO and strontium titanate were synthesized and characterized before ... Microwave absorption capabilities of the composite absorbers were investigated using a .... was backed with a conducting metal sheet.

A study on characteristic of selective membrane for strontium analysis

Energy Technology Data Exchange (ETDEWEB)

Moon, Seung Hyun; Choi, Young Woo [Kwang-ju Institute of Science and Technology, Kwangju (Korea)

1999-04-01

In this study, supported liquid membranes (SLMs) using crown ether were prepared in order to separate strontium ion selectively from a calcium contained solution However, at the higher than 3 N nitric acid concentration of a strip solution, stability of a SLM was declined remarkably owing to the hasty loss of carrier impregnated in supporter and, on account of this phenomena, facilitated transports were not accomplished. And DC18C6 as a neutral carrier affected remarkably the selectivity of strontium and the factor determining permeabilities of metal ions was as a role of DNNS. Consequently, in order to be a optimal SLM for the high permeability and the stable selectivity of strontium, concentration of DC18C6 and DNNS should be 0.1 M and 25 mM, respectively and, at this condition, the relative removal ratio of strontium to calcium was 93.3%. And the change of calcium concentration in the feed solution affected the permeability of strontium. In particular, when the ratio of strontium to calcium concentration in the feed solution was in the range of 1/5 - 1/50, strontium could be separated selectively at stable permeabilities. (author). 17 refs., 19 figs., 3 tabs.

Strontium isotopic stratigraphy utilizing authigenic dolomites in hemipelagic sediments

Energy Technology Data Exchange (ETDEWEB)

Baker, P.A. (Duke Univ., Durham, NC (USA)); Kastner, M. (Scripps Institute of Oceanography, La Jolla, CA (USA)); Elderfield, H. (Univ. of Cambridge (England))

1990-05-01

Authigenic dolomites commonly occur in organic-rich, continental margin marine sediments. These dolomites play a key role in the age dating of stratigraphic sections. The dolomites often are the only lithology amenable to paleomagnetic stratigraphy; they preserve siliceous microfossils against diagenetic; recrystallization, and provide useful strontium isotopic stratigraphic ages. Several potential sources of error frequently are unique to the use of authigenic dolomites in the strontium isotope methods. (1) The dolomites occur as cements of the host lithology, hence, they are not a pure phase. Potentially important contaminants during analysis include gypsum clay minerals, feldspars, and iron and manganese oxides. Strontium may occur as a structural substituent ion in these minerals or as a surface-adsorbed ion. Various leaching techniques have been tested to isolate dolomitic strontium. Purer dolomites and strontium-enriched dolomites often can be selected to ease these problems. (2) The dolomites form after the deposition of the host sediment, therefore, they record the diagenetic age not the depositional age. The stable isotopic composition of the dolomites can aid in selection of early formed samples. (3) The dolomites record pore-water strontium isotope compositions, not seawater isotopic compositions. This problem is also minimized by choosing dolomites formed near the sediment-water interface. (4) The dolomites formed near the sediment-water interface originated as rotodolomites and undergo subsequent burial diagenesis, creating a potential for later strontium isotope exchange. This problem is minimized by selecting fresh samples from the interior of nearly impermeable beds and nodules. Results from the Miocene Monterey Formation of California and from the Eocene through Pliocene Pisco basin of Peru show that authigenic dolomites can provide useful strontium isotopic age estimates.

Strontium-90 (90Sr) determination using liquid scintillation counting

International Nuclear Information System (INIS)

Cheberle, L.T.V.; Rosa, M.M.L.; Ferreira, M.T.; Taddei, M.H.T.

2015-01-01

This procedure describes a method for separation and measurement of strontium 90 Sr in water, soils, and biological samples. Water samples may be concentrated using evaporation or calcium phosphate coprecipitation. Soils and biological materials must be dissolved using wet digestion. Tracers and carriers must be added before the attack. Radioactive strontium is separated employing a specific resin before determination by liquid scintillation counting using the double energetic window method. The resin is used to concentrate strontium from samples. Stable strontium is used to monitor method yields and correct results to improve precision and accuracy. The presence of elemental strontium in the sample may bias the gravimetric yield determination. If it is suspected that natural strontium is present in the sample, its concentration should be determined by a suitable means (ICP), and the yield calculation properly modified. Sr-Spec resin with an 8M HNO 3 load solution is used to effectively remove 140 Ba and 40 K isotopes, as well as other interferences from the matrix. Tetravalent plutonium, neptunium, cerium and ruthenium, however, are not removed using nitric acid. The radiochemical procedure was tested using PROCORAD intercomparison exercises and PNI samples. (author)

The Strontium Isotope Record of Zavkhan Terrane Carbonates: Strontium Isotope Stability Through the Ediacaran-Cambrian Transition

OpenAIRE

Petach, Tanya N.

2015-01-01

First order trends in the strontium isotopic (87Sr/86Sr) composition of seawater are controlled by radiogenic inputs from the continent and non-radiogenic inputs from exchange at mid-ocean ridges. Carbonates precipitated in seawater preserve trace amounts of strontium that record this isotope ratio and therefore record the relative importance of mid-ocean ridge and weathering chemical inputs to sea water composition. It has been proposed that environmental changes during the Ediacaran-Cambria...

Seawater strontium isotopes, acid rain, and the Cretaceous-Tertiary boundary

Science.gov (United States)

Macdougall, J. D.

1988-01-01

A large bolide impact at the end of the Cretaceous would have produced significant amounts of nitrogen oxides by shock heating of the atmosphere. The resulting acid precipitation would have increased continental weathering greatly and could be an explanation for the observed high ratio of strontium-87 to strontium-86 in seawater at about this time, due to the dissolution of large amounts of strontium from the continental crust. Spikes to high values in the seawater strontium isotope record at other times may reflect similar episodes.

Structural, magnetic and microwave absorption behavior of Co-Zr substituted strontium hexaferrites prepared using tartaric acid fuel for electromagnetic interference suppression

Energy Technology Data Exchange (ETDEWEB)

Kaur, Prabhjyot, E-mail: prabhjyot.2525@gmail.com [Department of Chemistry, Centre for Advanced Studies-I, Guru Nanak Dev University, Amritsar 143005 (India); Chawla, S.K., E-mail: sschawla118@gmail.com [Department of Chemistry, Centre for Advanced Studies-I, Guru Nanak Dev University, Amritsar 143005 (India); Narang, Sukhleen Bindra, E-mail: sukhleen2@yahoo.com [Department of Electronics Technology, Guru Nanak Dev University, Amritsar 143005 (India); Pubby, Kunal, E-mail: kunalpubby02@gmail.com [Department of Electronics Technology, Guru Nanak Dev University, Amritsar 143005 (India)

2017-01-15

Strontium hexaferrites, doped with varying Co-Zr content (x) have been synthesized by sol-gel auto-combustion route using tartaric acid as fuel at 800 °C. X-ray diffraction and Fourier transform Infra-red have been carried out to confirm the phase formation, particle size (average 21.9–36.8 nm) and the bond formation respectively. Magnetic properties are scrutinized using vibrating sample magnetometer. Techniques like scanning electron microscopy, transmission electron microscopy and energy dispersive scattering have been employed to explore the surface morphology, particle size and composition of the nano-powders. Electromagnetic characterization of the prepared ferrites has been done using Vector Network Anlyzer in 12.4–18 GHz frequency range. The effect of calcination temperature (500–1000 °C) on the structure, morphology and magnetic properties has also been studied for x=0.2 and 800 °C has been found to be the most suitable temperature with the best magnetic properties. Increase in doping has resulted in resonance peaks in dielectric and magnetic loss spectra, leading to microwave absorption peaks. Ferrites with x=0.2, 0.8 and 1.0 have appropriate reflection loss less than −10 dB and bandwidth in Ku-band, hence can be used as effective absorbers in suppression of electromagnetic interference (EMI). The governance of impedance matching in deciding the absorption properties has been proved by using input impedance calculations. - Highlights: • Co-Zr doped strontium hexaferrite nanopowders have been prepared by sol-gel route. • 800 °C was most suitable temperaturewith best structural and magnetic properties. • Samples have M-type hexagonal structure with an average particle size of 36.47 nm. • Samples x=0.2, 0.8 and 1.0 are suitable for suppression of EM waves in Ku-band. • The origin of absorption peaks: impedance matching and losses has been explained.

Strontium ranelate for preventing and treating postmenopausal osteoporosis.

Science.gov (United States)

O'Donnell, S; Cranney, A; Wells, G A; Adachi, J D; Reginster, J Y

2006-10-18

Strontium ranelate is a new treatment for osteoporosis therefore, its benefits and harms need to be known. To determine the efficacy and safety of strontium ranelate for the treatment and prevention of postmenopausal osteoporosis. We searched MEDLINE (1996 to March 2005), EMBASE (1996 to week 9 2005), the Cochrane Library (1996 to Issue 1 2005), reference lists of relevant articles and conference proceedings from the last two years. Additional data was sought from authors. We included randomized controlled trials (RCTs) of at least one year duration comparing strontium ranelate versus placebo reporting fracture incidence, bone mineral density (BMD), health related quality of life or safety in postmenopausal women. Treatment (versus prevention) population was defined as women with prevalent vertebral fractures and/or lumbar spine BMD T score gastritis or death. Additional data suggests that the risk of vascular and nervous system side-effects is slightly increased with taking 2 g of strontium ranelate daily over three to four years. There is silver level evidence (www.cochranemsk.org) to support the efficacy of strontium ranelate for the reduction of fractures (vertebral and to a lesser extent non-vertebral) in postmenopausal osteoporotic women and an increase in BMD in postmenopausal women with/without osteoporosis. Diarrhea may occur however, adverse events leading to study withdrawal were not significantly increased with taking 2 g of strontium ranelate daily. Potential vascular and neurological side-effects need to be further explored.

Characterization of Lanthanum Ferric Cobaltite doped with Strontium (LSCF) films deposited by spray-pyrolysis for application as cathode in PaCOS-TI; Caracterizacao de filmes de CFLE depositados por spray-pirolise para utilizacao como catodo em PaCOS-TI

Energy Technology Data Exchange (ETDEWEB)

Almeida, L.S.; Guimaraes, V.F.; Paes Junior, H.R. [Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), Campos dos Goytacazes, RJ (Brazil). Lab. de Materiais Avancados], Emails: laryssadsa@yahoo.com.br, valtencyguimaraes@yahoo.com.br, herval@uenf.br

2010-07-01

The lanthanum ferric cobaltite doped with strontium (LSCF) is a ceramic material with the perovskite structure that stands out in the field of research for its use as cathode in solid oxide fuel cells at intermediate temperatures (IT-SOFC). The films were synthesized by spray-pyrolysis technique on 8% mol Yttria stabilized zirconia (YSZ) substrates. It was studied the influence of heat treatment temperatures (600-1000 deg C) on the properties of the films under the conditions of treatment during four hours. Samples were tested electrically by measuring the variation of electrical conductivity with temperature, structurally by X-ray diffraction (XRD) and morphologically by scanning electron microscopy (SEM). The films heat treated at 700 deg C for 4 hours showed better performance for application as cathode. (author)

Optical properties of Eu(III) doped strontium gadolinium niobate oxide

Energy Technology Data Exchange (ETDEWEB)

Vishwnath, Verma, E-mail: mnsmsu@gmail.com, E-mail: vermavicky.1988@gmail.com; Srinivas, M.; Patel, Nimesh; Modi, Dhaval [Luminescent Materials Laboratory, Physics Department, Faculty of Science, The M. S. University of Baroda, Vadodara-390002 (India); Murthy, K. V. R. [Display Materials Laboratory, Applied Physics Department, Faculty of Technology and Engineering, The M. S. University of Baroda, Vadodara-390001, Gujarat (India)

2016-05-23

Sr{sub 2}GdNbO{sub 6} doped with trivalent ion of Eu phosphors having monoclinic phase of space group P2{sub 1}/n have been synthesized via solid state reaction method, and their photoluminescence properties have been examined under UV excitation. The emission peaks exhibited around 580, 596, and 610 nm wavelength. By using xenon lamp as a source of excitation having wavelengths at 254 and 262 nm, it is observed that the maximum light emission yielded in red region. It is inferred that the dopant Eu{sup +3} ions may take the substitutional positions at non-centrosymmetric site.

Strontium-90 at the Hanford Site and its ecological implications

International Nuclear Information System (INIS)

RE Peterson; TM Poston

2000-01-01

Strontium-90, a radioactive contaminant from historical operations at the U.S. Department of Energy (DOE) Hanford Site, enters the Columbia River at several locations associated with former plutonium production reactors at the Site. Strontium-90 is of concern to humans and the environment because of its moderately long half-life (29.1 years), its potential for concentrating in bone tissue, and its relatively high energy of beta decay. Although strontium-90 in the environment is not a new issue for the Hanford Site, recent studies of near-river vegetation along the shoreline near the 100 Areas raised public concern about the possibility of strontium-90-contaminated groundwater reaching the riverbed and fall chinook salmon redds. To address these concerns, DOE asked Pacific Northwest National Laboratory (PNNL) to prepare this report on strontium-90, its distribution in groundwater, how and where it enters the river, and its potential ecological impacts, particularly with respect to fall chinook salmon. The purpose of the report is to characterize groundwater contaminants in the near-shore environment and to assess the potential for ecological impact using salmon embryos, one of the most sensitive ecological indicators for aquatic organisms. Section 2.0 of the report provides background information on strontium-90 at the Hanford Site related to historical operations. Public access to information on strontium-90 also is described. Section 3.0 focuses on key issues associated with strontium-90 contamination in groundwater that discharges in the Hanford Reach. The occurrence and distribution of fall chinook salmon redds in the Hanford Reach and characteristics of salmon spawning are described in Section 4.0. Section 5.0 describes the regulatory standards and criteria used to set action levels for strontium-90. Recommendations for initiating additional monitoring and remedial action associated with strontium-90 contamination at the Hanford Site are presented in Section 6

Strontium-90 at the Hanford Site and its ecological implications

Energy Technology Data Exchange (ETDEWEB)

RE Peterson; TM Poston

2000-05-22

Strontium-90, a radioactive contaminant from historical operations at the U.S. Department of Energy (DOE) Hanford Site, enters the Columbia River at several locations associated with former plutonium production reactors at the Site. Strontium-90 is of concern to humans and the environment because of its moderately long half-life (29.1 years), its potential for concentrating in bone tissue, and its relatively high energy of beta decay. Although strontium-90 in the environment is not a new issue for the Hanford Site, recent studies of near-river vegetation along the shoreline near the 100 Areas raised public concern about the possibility of strontium-90-contaminated groundwater reaching the riverbed and fall chinook salmon redds. To address these concerns, DOE asked Pacific Northwest National Laboratory (PNNL) to prepare this report on strontium-90, its distribution in groundwater, how and where it enters the river, and its potential ecological impacts, particularly with respect to fall chinook salmon. The purpose of the report is to characterize groundwater contaminants in the near-shore environment and to assess the potential for ecological impact using salmon embryos, one of the most sensitive ecological indicators for aquatic organisms. Section 2.0 of the report provides background information on strontium-90 at the Hanford Site related to historical operations. Public access to information on strontium-90 also is described. Section 3.0 focuses on key issues associated with strontium-90 contamination in groundwater that discharges in the Hanford Reach. The occurrence and distribution of fall chinook salmon redds in the Hanford Reach and characteristics of salmon spawning are described in Section 4.0. Section 5.0 describes the regulatory standards and criteria used to set action levels for strontium-90. Recommendations for initiating additional monitoring and remedial action associated with strontium-90 contamination at the Hanford Site are presented in Section 6

Effect of donor and acceptor dopants on crystallization, microstructural and dielectric behaviors of barium strontium titanate glass ceramics

Energy Technology Data Exchange (ETDEWEB)

Yadav, Avadhesh Kumar, E-mail: yadav.av11@gmail.com [Department of Physics, Dr. Bheem Rao Ambedkar Government Degree College, Anaugi, Kannauj (India); Gautam, C.R. [Department of Physics, University of Lucknow, Lucknow 226007 (India); Singh, Prabhakar [Department of Physics, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India)

2016-07-05

Bulk transparent barium strontium titanate borosilicate glasses in glass system (65-x)[(Ba{sub 0.6}Sr{sub 0.4}).TiO{sub 3}]-30[2SiO{sub 2}.B{sub 2}O{sub 3}]-5[K{sub 2}O]-x[A{sub 2}O{sub 3}], A = La, Fe (x = 2, 5 and 10) were prepared by rapid melt-quench technique and subsequently, converted into glass ceramics by regulated heat treatment process. The phase identification was carried out by X-ray powder diffraction and their surface morphology was studied by scanning electron microscopy. The dielectric properties were studied by impedance spectroscopic technique. Investigated glass samples were crystallized into major and secondary phases of Ba{sub 1.91}Sr{sub 0.09}TiO{sub 4} and Ba{sub 2}TiSi{sub 2}O{sub 8}, respectively. A very high dielectric constant having value upto 68000 was found in glass ceramic sample BST5K10F. This high value of dielectric constant was attributed to interfacial polarization, which arose due to conductivity difference among semiconducting crystalline phases, conducting grains and insulating grain boundaries. Donor dopant La{sub 2}O{sub 3} and acceptor dopant Fe{sub 2}O{sub 3} play an important role for enhancing crystallization, dielectric constant and retardation of dielectric loss in the samples. Moreover, higher value of dielectric constant and lower value of dielectric loss was found in Fe{sub 2}O{sub 3} doped samples in comparison to La{sub 2}O{sub 3} doped samples. - Highlights: • Bulk transparent barium strontium titanate glasses are successfully prepared. • A very high dielectric constant upto 68000 was found in glass ceramics. • La{sub 2}O{sub 3} and Fe{sub 2}O{sub 3} play role for enhancing value of dielectric constant. • Higher dielectric constant with low dielectric loss was found in Fe{sub 2}O{sub 3} doped sample. • Such glass ceramics may be used in making capacitors for high energy storage.

Strontium 90 in Swedish dairy milk 1978

International Nuclear Information System (INIS)

Gillberg-Wickman, M.; Oestergren, I.

1980-01-01

The contamination of strontium-90 in Swedish milk during 1978 is practically the same as in 1977. The country-wide mean ratio of strontium-90 to calcium in milk is 0.12 Bq 90 Sr(gCa) -1 , based on monthly determinations of samples obtained from 8 dairy plants situated throughout the country. (author)

Cesium and Strontium Separation Technologies Literature Review

Energy Technology Data Exchange (ETDEWEB)

T. A. Todd; T. A. Todd; J. D. Law; R. S. Herbst

2004-03-01

Integral to the Advanced Fuel Cycle Initiative (AFCI) Program’s proposed closed nuclear fuel cycle, the fission products cesium and strontium in the dissolved spent nuclear fuel stream are to be separated and managed separately. A comprehensive literature survey is presented to identify cesium and strontium separation technologies that have the highest potential and to focus research and development efforts on these technologies. Removal of these high-heat-emitting fission products reduces the radiation fields in subsequent fuel cycle reprocessing streams and provides a significant short-term (100 yr) heat source reduction in the repository. This, along with separation of actinides, may provide a substantial future improvement in the amount of fuel that could be stored in a geologic repository. The survey and review of the candidate cesium and strontium separation technologies are presented herein. Because the AFCI program intends to manage cesium and strontium together, technologies that simultaneously separate both elements are of the greatest interest, relative to technologies that separate only one of the two elements.

Bactericidal strontium-releasing injectable bone cements based on bioactive glasses.

Science.gov (United States)

Brauer, Delia S; Karpukhina, Natalia; Kedia, Gopal; Bhat, Aditya; Law, Robert V; Radecka, Izabela; Hill, Robert G

2013-01-06

Strontium-releasing injectable bone cements may have the potential to prevent implant-related infections through the bactericidal action of strontium, while enhancing bone formation in patients suffering from osteoporosis. A melt-derived bioactive glass (BG) series (SiO2–CaO–CaF2–MgO) with 0–50% of calcium substituted with strontium on a molar base were produced. By mixing glass powder, poly(acrylic acid) and water, cements were obtained which can be delivered by injection and set in situ, giving compressive strength of up to 35 MPa. Strontium release was dependent on BG composition with increasing strontium substitution resulting in higher concentrations in the medium. Bactericidal effects were tested on Staphylococcus aureus and Streptococcus faecalis; cell counts were reduced by up to three orders of magnitude over 6 days. Results show that bactericidal action can be increased through BG strontium substitution, allowing for the design of novel antimicrobial and bone enhancing cements for use in vertebroplasty or kyphoplasty for treating osteoporosis-related vertebral compression fractures.

Analysis of radioactive strontium

International Nuclear Information System (INIS)

1977-01-01

In environmental radiation survey, radioactive strontium has been analyzed in compliance with the manual ''Analyzing methods for radioactive strontium'' published in 1960 by the Science and Technology Agency, Japan, and revised in 1963. However, in a past decade, progress and development in analyzing methods and measuring equipments have been significant, therefore the manual was revised in 1974. Major revisions are as follows. (1) Analysis of 90 Sr with long half life was changed to the main theme and that of 89 Sr with short half life became a subordinate one. (2) Measuring criteria and sampling volume were revised. (3) Sample collection method was unified. (4) Analyzing method for soil was improved to NaOH-HCl method which has good recovery rate. (5) 90 Y separation method of simple operation was added for sea water analysis besides EDTA and fuming nitric acid methods. (6) Flame spectrometry for quantitative analysis of stable strontium was revised to atomic absorption spectrometry. The contents of the manual comprises 11 chapters describing introduction, measuring criteria for 90 Sr ( 89 Sr), rain and dust, land water, sea water, soil, sea bottom and river bottom sediments (changed from human urine and human bones), crops, milk (the previous one chapter was divided into two), marine organisms, and everyday foods, respectively. (Wakatsuki, Y.)

Conical light scattering in strontium barium niobate crystals related to an intrinsic composition inhomogeneity

International Nuclear Information System (INIS)

Bastwoeste, K; Sander, U; Imlau, M

2007-01-01

Conical light scattering is uncovered in poly- and mono-domain, nominally pure and Eu-doped strontium barium niobate (SBN) crystals over a wide temperature regime. The appearance of two scattering cones, a scattering line and a corona is observed and can be explained comprehensively within the Ewald sphere concept. Photorefraction, scattering from domain boundaries or from growth striations can be excluded from explaining the origin of the scattering. It is shown that the temperature-persistent scattering process is related to a growth-induced seeding rod, i.e. a composition inhomogeneity primarily localized at the centre of the SBN sample. The rod is directed parallel to the c axis and yields a refractive-index inhomogeneity with spatial frequencies on the micro-scale

Reduced-graphene-oxide-and-strontium-titanate-based double

Indian Academy of Sciences (India)

Microwave-absorbing materials based on reduced graphene oxide (r-GO)/ strontium titanate were prepared by embedding in epoxy matrix. R-GO and strontium titanate were synthesized and characterized before composite fabrication. Microstructures of the constituent elements were studied by scanning electron ...

Cation interdiffusion in polycrystalline calcium and strontium titanate

International Nuclear Information System (INIS)

Butler, E.P.; Jain, H.; Smyth, D.M.

1991-01-01

This paper discusses a method that has been developed to study bulk lattice interdiffusion between calcium and strontium titanate by fabrication of a diffusion couple using cosintering. The measured interdiffusion coefficients, D(C), indicate that strontium impurity diffusion in calcium titanate occurs at a faster rate than calcium impurity diffusion in strontium titanate. These interdiffusion coefficients are composition independent when the concentration of the calcium cation exceeds that of the strontium cation; otherwise D(C) is strongly composition dependent. Investigations into the effect of cation nonstoichiometry give results that are consistent with a defect incorporation reaction in which excess TiO 2 , within the solid solubility limit, produces A-site cation vacancies as compensating defects. The interdiffusion coefficients increase with increasing concentrations of TiO 2 , so it is concluded that interdiffusion of these alkaline-earth cations in their titanates occurs via a vacancy mechanism

Effect of certain alkaline metals on Pr doped glasses to investigate spectroscopic studies

Science.gov (United States)

Lenkennavar Susheela, K.; Madhu, A.; Eraiah, B.; Kokila, M. K.

2018-02-01

Incorporation of different Alkaline earth metal like Barium, Calcium and strontium in sodium lead borate glass doped with Pr3+ is studied. Physical parameters such as density, molar volume, molar refractivity etc have been evaluated. Effect of different atomic size of alkaline metal using optical and physical parameters is analysed. XRD and FTIR were carried out to know the structural behaviour of the glasses. Absorption and Emission spectra are recorded at room temperature and the results were discussed.

Isomorfic Substitutions of Calcium by Strontium in Calcium Hydroxyapatite

International Nuclear Information System (INIS)

Christensen, Hilbert

1962-12-01

By means of homogeneous precipitation it has been possible to synthesize crystalline solid solutions of calcium strontium hydroxyapatite from aqueous solutions. The lattice constants for the solid solutions were measured in the range Ca 9 Sr(PO 4 ) 6 (OH) 2 - CaSr 9 (PO 4 ) 6 (OH) 2 . The investigations show that the discrimination of strontium against calcium is considerably smaller than reported elsewhere (1). Strontium is preferentially built into the c-axis direction of the apatite lattice

Photoluminescence properties and energy-transfer of thermal-stable Ce3+, Mn2+-codoped barium strontium lithium silicate red phosphors

International Nuclear Information System (INIS)

Zhang Xinguo; Gong Menglian

2011-01-01

Research highlights: → Excited by UV, strong red luminescence is observed from Ce 3+ , Mn 2+ -codoped barium strontium lithium silicate (BSLS), while violet-blue emission from Ce 3+ sole doped BSLS. → These results indicate the Mn 2+ -derived red emission is originated by an efficient Ce 3+ → Mn 2+ energy transfer. → The red emission becomes stronger with increased Sr content, and shows red-shift. → These phosphors demonstrate good thermal stability even in 180 o C, which is suitable for NUV LED application. - Abstract: A series of thermal-stable Ce 3+ , Mn 2+ -codoped barium strontium lithium silicate (BSLS) phosphors was synthesized by a high-temperature solid-state reaction. The XRD patterns of this phosphor seem to be a new phase that has not been reported before. BSLS:Ce 3+ , Mn 2+ showed two emission bands under 365 nm excitation: one observed at 421 nm was attributed to Ce 3+ emission, and the other found in red region was assigned to Mn 2+ emission through Ce 3+ -Mn 2+ efficient energy transfer. The Mn 2+ emission shifted red along with the replacement of barium by strontium, which was due to the change of crystal field. A composition-optimized phosphor, BSLS:0.10Ce 3+ , 0.05Mn 2+ (Ba = 65), exhibited strong and broad red-emitting and supreme thermal stability. The results suggest that this phosphor is suitable as a red component for NUV LED or high pressure Hg vapor (HPMV) lamp.

Morphological control of strontium oxalate particles by PSMA-mediated precipitation reaction

Energy Technology Data Exchange (ETDEWEB)

Yu Jiaguo [State Key Laboratory of Advanced Technology for Material Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China)]. E-mail: jiaguoyu@yahoo.com; Tang Hua [State Key Laboratory of Advanced Technology for Material Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Cheng Bei [State Key Laboratory of Advanced Technology for Material Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China)

2005-05-15

In this paper, strontium oxalate particles with different morphologies could be easily obtained by a precipitation reaction of sodium oxalate with strontium chloride in the absence and presence of poly-(styrene-alt-maleic acid) (PSMA). The as-prepared products were characterized with scanning electron microscopy and X-ray diffraction. The effects of pH, aging time and concentration of PSMA on the phase structures and morphologies of the as-prepared strontium oxalate particles were investigated and discussed. The results showed that strontium oxalate particles with various morphologies, such as, bi-pyramids, rods, peanuts, and spherical particles, etc., could be obtained by varying the experimental conditions. PSMA promoted the formation of strontium oxalate dihydrate (SOD) phase. Suitable pH values (pH 7 and 8) favor the formation of the peanut-shaped SrC{sub 2}O{sub 4} particles. This research may provide new insight into the control of morphologies and phase structures of strontium oxalate particles and the biomimetic synthesis of novel inorganic materials.

Surface adsorption in strontium chloride ammines

DEFF Research Database (Denmark)

Ammitzbøll, Andreas L.; Lysgaard, Steen; Klukowska, Agata

2013-01-01

An adsorbed state and its implications on the ab- and desorption kinetics of ammonia in strontium chloride ammine is identified using a combination of ammonia absorption measurements, thermogravimetric analysis, and density functional theory calculations. During thermogravimetric analysis, ammonia...... desorption originating from the adsorbed state is directly observed below the bulk desorption temperature, as confirmed by density functional theory calculations. The desorption enthalpy of the adsorbed state of strontium chloride octa-ammine is determined with both techniques to be around 37-39 k...

Isomorfic Substitutions of Calcium by Strontium in Calcium Hydroxyapatite

Energy Technology Data Exchange (ETDEWEB)

Christensen, Hilbert

1962-12-15

By means of homogeneous precipitation it has been possible to synthesize crystalline solid solutions of calcium strontium hydroxyapatite from aqueous solutions. The lattice constants for the solid solutions were measured in the range Ca{sub 9}Sr(PO{sub 4}){sub 6}(OH){sub 2} - CaSr{sub 9}(PO{sub 4}){sub 6}(OH){sub 2}. The investigations show that the discrimination of strontium against calcium is considerably smaller than reported elsewhere (1). Strontium is preferentially built into the c-axis direction of the apatite lattice.

Sea water strontium isotopes, acid rain, and the cretaceous-tertiary boundary

International Nuclear Information System (INIS)

MacDougall, J.D.

1988-01-01

A large bolide impact at the end of the Cretaceous would have produced significant amounts of nitrogen oxides by shock heating of the atmosphere. The resulting acid precipitation would have increased continental weathering greatly and could be an explanation for the observed high ratio of strontium-87 to strontium-86 in sea water at about this time, due to the dissolution of large amounts of strontium from the continental crust. Spikes to high values in the sea water strontium isotope record at other times may reflect similar episodes. 17 references, 1 figure, 1 table

Strontium Promotes Cementoblasts Differentiation through Inhibiting Sclerostin Expression In Vitro

Directory of Open Access Journals (Sweden)

Xingfu Bao

2014-01-01

Full Text Available Cementogenesis, performed by cementoblasts, is important for the repair of root resorption caused by orthodontic treatment. Based on recent studies, strontium has been applied for osteoporosis treatment due to its positive effect on osteoblasts. Although promising, the effect of strontium on cementoblasts is still unclear. So the aim of this research was to clarify and investigate the effect of strontium on cementogenesis via employing cementoblasts as model. A series of experiments including MTT, alkaline phosphatase activity, gene analysis, alizarin red staining, and western blot were carried out to evaluate the proliferation and differentiation of cementoblasts. In addition, expression of sclerostin was checked to analyze the possible mechanism. Our results show that strontium inhibits the proliferation of cementoblasts with a dose dependent manner; however, it can promote the differentiation of cementoblasts via downregulating sclerostin expression. Taking together, strontium may facilitate cementogenesis and benefit the treatment of root resorption at a low dose.

A novel design of anode-supported solid oxide fuel cells with Y 2O 3-doped Bi 2O 3, LaGaO 3 and La-doped CeO 2 trilayer electrolyte

Science.gov (United States)

Guo, Weimin; Liu, Jiang

Anode-supported solid oxide fuel cells (SOFCs) with a trilayered yttria-doped bismuth oxide (YDB), strontium- and magnesium-doped lanthanum gallate (LSGM) and lanthanum-doped ceria (LDC) composite electrolyte film are developed. The cell with a YDB (18 μm)/LSGM (19 μm)/LDC (13 μm) composite electrolyte film (designated as cell-A) shows the open-circuit voltages (OCVs) slightly higher than that of a cell with an LSGM (31 μm)/LDC (17 μm) electrolyte film (designated as cell-B) in the operating temperature range of 500-700 °C. The cell-A using Ag-YDB composition as cathode exhibits lower polarization resistance and ohmic resistance than those of a cell-B at 700 °C. The results show that the introduction of YDB to an anode-supported SOFC with a LSGM/LDC composite electrolyte film can effectively block electronic transport through the cell and thus increased the OCVs, and can help the cell to achieve higher power output.

Depression Mechanism of Strontium Ions in Bastnaesite Flotation with Salicylhydroxamic Acid as Collector

Directory of Open Access Journals (Sweden)

Shiming Cao

2018-02-01

Full Text Available Metal ions are widely present in flotation pulp. Metal ions change solution chemistry and mineral surface properties, consequently affecting mineral flotation. In this work, the effect of strontium ions on bastnaesite flotation with salicylhydroxamic acid (SHA was investigated by microflotation tests, contact angle measurements, zeta-potential measurements, and X-ray photoelectron spectroscopy (XPS analysis. Microflotation tests confirmed that the addition of strontium ions decreased bastnaesite floatability, compared with that in the absence of strontium ions. Contact angle measurements suggested that the pretreatment of strontium ions decreased SHA adsorption. Zeta potential measurements confirmed that the bastnaesite was depressed by the adsorption of positively charged strontium species, and the lower adsorption capacity of SHA onto the bastnaesite surfaces was obtained after modifying with strontium ions. XPS analysis demonstrated that strontium ions adsorbed onto the bastnaesite surfaces through the interaction between strontium ions and oxygen atoms of surface ≡ CeOH 0 groups. This occurrence hindered surface Ce sites which chelated with SHA and therefore, decreased bastnaesite floatability.

Strontium-90 and cesium-137 in powdered milk

International Nuclear Information System (INIS)

1977-01-01

Japan Chemical Analysis Center has analysed the strontium-90 and cesium-137 content in powdered milk. The samples were purchased on the open market in Tokyo from the powdered milk producers. The analysis of Strontium-90 and Cesium-137 content was carried out using the method recommended by Science and Technology Agency. (author)

Flame Spectrophotometric Determination of Strontium in Water and Biological Material

Energy Technology Data Exchange (ETDEWEB)

Joensson, G

1964-10-15

A flame spectrophotometric method has been developed for the determination of strontium in biological material and water samples. Strontium is determined in the presence of calcium at a wavelength of 4607 A. The intensity of the strontium emission from the sample is increased if n-butanol is added to a solution of the sample in water. With a 6 vol% solution of n-butanol in water, an optimum intensity of 3.5 times that obtained with pure water solution is obtained. Anions and alkali metals which might interfere with the flame spectrophotometric determination are separated from the sample by a simple ion exchange operation. The method allows determination of strontium in solutions down to 0.1{mu}g/ml. In this case the standard deviation is 3.1 % and with a strontium concentration of 1 {mu}g/ml the deviation is 0.9 %. This method has been used for the determination of strontium in samples of varying composition such as bone, meat and skin from fishes, samples of human bones, shell-fish, milk, and water, in which case Sr quantities of 5{mu}g were determined with an analytical error of less than 5 % and Sr{sub q}uantities greater than 10 {mu}g with an error of less than 3 %.

Flame Spectrophotometric Determination of Strontium in Water and Biological Material

International Nuclear Information System (INIS)

Joensson, G.

1964-10-01

A flame spectrophotometric method has been developed for the determination of strontium in biological material and water samples. Strontium is determined in the presence of calcium at a wavelength of 4607 A. The intensity of the strontium emission from the sample is increased if n-butanol is added to a solution of the sample in water. With a 6 vol% solution of n-butanol in water, an optimum intensity of 3.5 times that obtained with pure water solution is obtained. Anions and alkali metals which might interfere with the flame spectrophotometric determination are separated from the sample by a simple ion exchange operation. The method allows determination of strontium in solutions down to 0.1μg/ml. In this case the standard deviation is 3.1 % and with a strontium concentration of 1 μg/ml the deviation is 0.9 %. This method has been used for the determination of strontium in samples of varying composition such as bone, meat and skin from fishes, samples of human bones, shell-fish, milk, and water, in which case Sr quantities of 5μg were determined with an analytical error of less than 5 % and Sr q uantities greater than 10 μg with an error of less than 3 %

Strontium eluting graphene hybrid nanoparticles augment osteogenesis in a 3D tissue scaffold

Science.gov (United States)

Kumar, Sachin; Chatterjee, Kaushik

2015-01-01

The objective of this work was to prepare hybrid nanoparticles of graphene sheets decorated with strontium metallic nanoparticles and demonstrate their advantages in bone tissue engineering. Strontium-decorated reduced graphene oxide (RGO_Sr) hybrid nanoparticles were synthesized by the facile reduction of graphene oxide and strontium nitrate. X-ray diffraction, transmission electron microscopy, and atomic force microscopy revealed that the hybrid particles were composed of RGO sheets decorated with 200-300 nm metallic strontium particles. Thermal gravimetric analysis further confirmed the composition of the hybrid particles as 22 wt% of strontium. Macroporous tissue scaffolds were prepared by incorporating RGO_Sr particles in poly(ε-caprolactone) (PCL). The PCL/RGO_Sr scaffolds were found to elute strontium ions in aqueous medium. Osteoblast proliferation and differentiation was significantly higher in the PCL scaffolds containing the RGO_Sr particles in contrast to neat PCL and PCL/RGO scaffolds. The increased biological activity can be attributed to the release of strontium ions from the hybrid nanoparticles. This study demonstrates that composites prepared using hybrid nanoparticles that elute strontium ions can be used to prepare multifunctional scaffolds with good mechanical and osteoinductive properties. These findings have important implications for designing the next generation of biomaterials for use in tissue regeneration.The objective of this work was to prepare hybrid nanoparticles of graphene sheets decorated with strontium metallic nanoparticles and demonstrate their advantages in bone tissue engineering. Strontium-decorated reduced graphene oxide (RGO_Sr) hybrid nanoparticles were synthesized by the facile reduction of graphene oxide and strontium nitrate. X-ray diffraction, transmission electron microscopy, and atomic force microscopy revealed that the hybrid particles were composed of RGO sheets decorated with 200-300 nm metallic strontium

Effect of competing cations on strontium sorption to surficial sediments

International Nuclear Information System (INIS)

Bunde, R.L.; Rosentreter, J.J.

1995-01-01

The following study was conducted to determine strontium distribution coefficients (K d 'S) of a surficial sediment at the Idaho National Engineering Laboratory (INEL), Idaho. Batch experimental techniques were used to determine K d 's which describe the partitioning of a solute between the solution and solid phase. A surficial sediment was mixed with synthesized aqueous solutions designed to chemically simulate wastewater disposed to infiltrations ponds near the Idaho Chemical Processing Plant at the INEL with respect to major ionic character and pH. The effects of variable concentrations of competing cations (sodium, potassium, calcium and magnesium) on strontium sorption were investigated at a fixed pH of 8.00. The pH of the natural system shows no appreciable variation, whereas a marked variability in cation concentration has been noted. Strontium sorption was impacted to a greater degree by the concentration of calcium and magnesium in solution than by the presence of sodium or potassium. However, extreme sodium solution concentrations of 1.0 to 5.0 g/L dramatically reduced strontium sorption. In all cases, strontium K d 's decreased as the concentration of calcium and magnesium in solution increased. Linear isotherm model K d 's ranged from 12.0 to 84.7 mL/g. Analysis of data from these experiments indicated that moderate concentrations of calcium and magnesium (less than 40 mg/L) and high concentrations of sodium (1.0 to 5.0 g/L) in wastewater increase strontium mobility by decreasing the sorption of strontium on surficial sediments beneath infiltration ponds at the INEL

Strontium migration in a crystalline medium: effects of the presence of bentonite colloids.

Science.gov (United States)

Albarran, Nairoby; Missana, Tiziana; García-Gutiérrez, Miguel; Alonso, Ursula; Mingarro, Manuel

2011-03-25

The effects of bentonite colloids on strontium migration in fractured crystalline medium were investigated. We analyzed first the transport behaviour of bentonite colloids alone at different flow rates; then we compared the transport behaviour of strontium as solute and of strontium previously adsorbed onto stable bentonite colloids at a water velocity of approximately 7.1·10(-6)m/s-224m/yr. Experiments with bentonite colloids alone showed that - at the lowest water flow rate used in our experiments (7.1·10(-6)m/s) - approximately 70% of the initially injected colloids were retained in the fracture. Nevertheless, the mobile colloidal fraction, moved through the fracture without retardation, at any flow rate. Bentonite colloids deposited over the fracture surface were identified during post-mortem analyses. The breakthrough curve of strontium as a solute, presented a retardation factor, R(f)~6, in agreement with its sorption onto the granite fracture surface. The breakthrough curve of strontium in the presence of bentonite colloids was much more complex, suggesting additional contributions of colloids to strontium transport. A very small fraction of strontium adsorbed on mobile colloids moved un-retarded (R(f)=1) and this fraction was much lower than the expected, considering the quantity of strontium initially adsorbed onto colloids (90%). This behaviour suggests the hypothesis of strontium sorption reversibility from colloids. On the other hand, bentonite colloids retained within the granite fracture played a major role, contributing to a slower strontium transport in comparison with strontium as a solute. This was shown by a clear peak in the breakthrough curve corresponding to a retardation factor of approximately 20. Copyright © 2010 Elsevier B.V. All rights reserved.

Strontium incorporates at sites critical for bone mineralization in rats with renal failure

International Nuclear Information System (INIS)

Oste, Line; Verberckmoes, Steven C.; Behets, Geert J.; Dams, Geert; Bervoets, An R.; De Broe, Marc E.; D'Haese, Patrick C.; Van Hoof, Viviane O.; Bohic, Sylvain; Drakopoulos, Michael

2007-01-01

We previously demonstrated the development of a mineralization defect during strontium administration and its reversibility after withdrawal in rats with chronic renal failure. Recently, strontium ranelate has been introduced as a therapeutic agent for osteoporosis. However, caution has to be taken, as this bone disorder mainly develops in elderly people who may present a moderately decreased renal function. In order to assess the ultra-structural localization of strontium in bone and thereby to get a better insight into the element's systemic effects on bone, synchrotron-based x-ray micro-fluorescence was applied, which showed that after 2 weeks of strontium loading (2 g l -1 in drinking water) in rats with renal failure, concomitant with the development of impaired mineralization, the element was localized mainly at the outer edge of the mineralized bone, while after longer loading periods, a more homogeneous distribution was found. After washout, strontium was found at sites deeper within the trabeculae, while newly deposited low-strontium-containing mineral was found at the outer edges. Synchrotron x-ray micro-diffraction analysis showed that strontium is incorporated in the apatite crystal lattice through exchange with calcium. The results show that strontium is initially incorporated in bone at sites of active bone mineralization, close to the osteoid/mineralization front.Most likely, strontium binds to matrix proteins serving as crystal nucleation points and by hetero-ionic substitution with calcium within the hydroxyapatite crystals, thereby impairing further hydroxyapatite formation. After withdrawal, strontium is released from these sites, by which mineralization is restored and the previously formed strontium-containing hydroxyapatite is buried under a new layer of mineralized bone. (authors)

Photostriction of strontium ruthenate

KAUST Repository

Wei, Tzu-Chiao; Wang, Hsin-Ping; Liu, Heng-Jui; Tsai, Dung-Sheng; Ke, Jr-Jian; Wu, Chung-Lun; Yin, Yu-Peng; Zhan, Qian; Lin, Gong-Ru; Chu, Ying-Hao; He, Jr-Hau

2017-01-01

Transition metal oxides with a perovskite crystal structure exhibit a variety of physical properties associated with the lattice. Among these materials, strontium ruthenate (SrRuO3) displays unusually strong coupling of charge, spin and lattice

Strontium Localization in Bone Tissue Studied by X-Ray Absorption Spectroscopy

DEFF Research Database (Denmark)

Frankær, Christian Grundahl; Raffalt, Anders Christer; Ståhl, Kenny

2014-01-01

Strontium has recently been introduced as a pharmacological agent for the treatment and prevention of osteoporosis. We determined the localization of strontium incorporated into bone matrix from dogs treated with Sr malonate by X-ray absorption spectroscopy. A new approach for analyzing the X...... highly ordered sites, and at least 30 % is located at less ordered sites where only the first solvation shell is resolved, suggesting that strontium is sur- rounded by only oxygen atoms similar to Sr2? in solution. Strontium was furthermore shown to be absorbed in collagen in which it obtains a higher...

Strontium and calcium accumulation in fish as affected by food composition

International Nuclear Information System (INIS)

Ophel, I.L.; Judd, J.M.

1976-01-01

Radioactive tracers ( 85 Sr and 47 Ca) were used to investigate the effects of food composition on the accumulation of strontium and calcium by fish and their discrimination between these two elements. The total amount of calcium assimilated by fish was the same for all experimental conditions. Calcium not obtainable from food was absorbed from the water, even when the water concentration was less than 10 mg Ca/l. The major discriminatory process occurred during direct (gill) uptake from water. Gut uptake provided least discrimination against strontium. Strontium content of fish was closely related to the Sr/Ca ratio in their food. Strontium assimilation was found to be a function of: the Sr/Ca ratios of food and water, the amounts of calcium derived from each source and the biological discrimination against strontium relative to calcium

Study of effect of co-doping on CIE coordinates of strontium cerium oxide phosphor (Sr_2CeO_4)

International Nuclear Information System (INIS)

Zambare, Pradip Z.; Ahirrao, P.B.; Chaudhari, D.B.; Zambare, A.P.; Mahajan, O.H.

2016-01-01

The phosphors Sr_2CeO_4 doped europium and gadolinium were synthesized by modified solid state diffusion method. From emission spectra, the CIE coordinates (x, y) of x% Eu"3"+ and 0.5 %Gd"3"+ doped Sr_2CeO_4 phosphors was calculated. In present paper, we investigate luminescence properties and colorimetric study of Sr_2CeO_4 doped 0.5% Gd"3"+, x% Eu"3"+. The phosphors Sr_2CeO_4 doped europium and gadolinium were successfully synthesized by modified solid state diffusion method. X-ray diffraction (XRD) profile confirms the orthorhombic nature of Eu"3"+ and 0.5% Gd"3"+ doped Sr_2CeO_4 phosphors. In addition, scanning electron Microscopy (SEM), Fourier-Transformation IR spectroscopy (FTIR), was also used to study the synthesized phosphors

Strontium isotope geochemistry of soil and playa deposits near Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Marshall, B.D.; Mahan, S.A.

1994-01-01

The isotopic composition of strontium contained in the carbonate fractions of soils provides an excellent tracer which can be used to test models for their origin. This paper reports data on surface coatings and cements, eolian sediments, playas and alluvial fan soils which help to constrain a model for formation of the extensive calcretes and fault infillings in the Yucca Mountain region. The playas contain carbonate with a wide range of strontium compositions; further work will be required to fully understand their possible contributions to the pedogenic carbonate system. Soils from an alluvial fan to the west of Yucca Mountain show that only small amounts of strontium are derived from a fan draining a carbonate terrane have strontium component. Although much evidence points to an eolian source for at least some of the strontium in the pedogenic carbonates near Yucca Mountain, an additional component or past variation of strontium composition in the eolian source is required to model the pedogenic carbonate system

Influence of granular strontium chloride as additives on some ...

Indian Academy of Sciences (India)

Influence of granular strontium chloride as additives on some electrical and mechanical properties for pure polyvinyl alcohol. A B Elaydy M Hafez ... Keywords. Polyvinyl-alcohol (PVA); granular strontium chloride, SrCl2; a.c. electrical conductivity; dielectric constant; dielectric loss; Young's modulus; creep relaxation curve.

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 calcium...

Investigation of Varied Strontium-Transuranic Precipitation Chemistries for Crossflow

International Nuclear Information System (INIS)

Nash, C.A.

2000-01-01

Precipitation chemistries for strontium and transuranic (TRU) removal have been tested for crossflow filterability and lanthanide removal with simulants of Hanford tank 241-AN-107 supernate. This is the initial work indicating the usefulness of a strontium and permanganate precipitation process as applied to the Hanford River Protection Project. Precipitations with both ferric and ferrous iron were shown to be at least two orders of magnitude less filterable than a 0.1 gpm/ft target average flux that was desired at the time. A precipitate from a strontium nitrate strike alone was found to filter easily and to make the desired average flux. Other chemistries tested included precipitant of lanthanum(III), nickel (II), calcium (II), and a redox chemistry using sodium permanganate. Of these chemistries a strontium and permanganate strike including calcium provided the highest filter flux compared to the other chemistries. It showed the most promise in lanthanide removal as well. This work provides a promising direction for further work to achieve both acceptable filterability and decontamination for Envelope C wastes to be treated by the Hanford River Protection Project. The work reported here was originally intended to satisfy needs for crossflow filter testing of a strontium and ferric precipitation method for treating Envelope C using a 241-AN-107 simulant

Spectroscopy and Laser-SNMS on stable and radioactive strontium

Energy Technology Data Exchange (ETDEWEB)

Bosco, Hauke; Walther, Clemens [Institut fuer Radiooekologie und Strahlenschutz, Leibniz Universitaet Hannover (Germany); Franzmann, Michael [Institut fuer Radiooekologie und Strahlenschutz, Leibniz Universitaet Hannover (Germany); Institut fuer Physik, Johannes Gutenberg Universitaet Mainz (Germany); Kron, Tobias; Wendt, Klaus [Institut fuer Physik, Johannes Gutenberg Universitaet Mainz (Germany)

2016-07-01

Nuclear accidents as experienced e.g. in Chernobyl or Fukushima and nuclear weapon tests released considerable activity levels and a variety of medium to long-lived radionuclides into the environment. Strontium-90 appears as a significant share of the fission products in spent nuclear fuel and correspondingly in any possible release. Due to its chemical properties it is subject to long range transport through the environment and can cause considerable dose to man when entering the food chain. Correspondingly, the investigation of speciation and migration channels is of major relevance. A radioanalytical approach is severely hampered by the low beta energy of the strontium-90 decay and the need to separate strontium-90 from the secular equilibrated daughter yttrium-90. Hence, application of a mass spectrometric method without chemical separation of the elements is a promising alternative for low-level investigation of strontium-90. Application of the new Laser-SNMS system at IRS Hannover could well suit those needs. It applies three Ti:Sa lasers for resonant ionization of neutral atoms produced by primary ion sputtering in a SIMS together with a time-of-flight mass analysis which provides high spatial resolution. The analytical measurements are preceded by spectroscopic studies on the level structure of strontium to develop a most efficient ionization scheme.

Investigation of Varied Strontium-Transuranic Precipitation Chemistries for Crossflow

Energy Technology Data Exchange (ETDEWEB)

Nash, C.A.

2000-07-27

Precipitation chemistries for strontium and transuranic (TRU) removal have been tested for crossflow filterability and lanthanide removal with simulants of Hanford tank 241-AN-107 supernate. This is the initial work indicating the usefulness of a strontium and permanganate precipitation process as applied to the Hanford River Protection Project. Precipitations with both ferric and ferrous iron were shown to be at least two orders of magnitude less filterable than a 0.1 gpm/ft target average flux that was desired at the time. A precipitate from a strontium nitrate strike alone was found to filter easily and to make the desired average flux. Other chemistries tested included precipitant of lanthanum(III), nickel (II), calcium (II), and a redox chemistry using sodium permanganate. Of these chemistries a strontium and permanganate strike including calcium provided the highest filter flux compared to the other chemistries. It showed the most promise in lanthanide removal as well. This work provides a promising direction for further work to achieve both acceptable filterability and decontamination for Envelope C wastes to be treated by the Hanford River Protection Project. The work reported here was originally intended to satisfy needs for crossflow filter testing of a strontium and ferric precipitation method for treating Envelope C using a 241-AN-107 simulant.

Strontium-90 in ion-exchange resin used in the Australian FIEFS network

International Nuclear Information System (INIS)

Wise, K.N.

1977-10-01

In order to determine monthly strontium-90 fallout deposited at the eight Australian monitoring stations, account must be taken of the level of strontium-90 contamination of the ion-exchange resin as prepared for use in the FIEFS. This procedure has always been important in monitoring strontium-90 fallout deposit in Australia because the level of strontium-90 contamination of ion-exchange resin, supplied by manufacturers in the Northern Hemisphere, has remained of the same order of magnitude as the monthly fallout deposit in the Southern Hemisphere

Strontium isotope geochemistry of soil and playa a deposits near Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Marshall, B.D.; Mahan, S.A.

1994-01-01

The isotopic composition of strontium contained in the carbonate fractions of soils provides an excellent tracer which can be used to test models for their origin. This paper reports data on surface coatings and cements, eolian sediments, playas and alluvial fan soils which help to constrain a model for formation of the extensive calcretes and fault infilling in the Yucca Mountain region. The playas contain carbonate with a wide range of strontium compositions; further work will be required to fully understand their possible contributions to the pedogenic carbonate system. Soils from an alluvial fan to the west of Yucca Mountain show that only small amounts of strontium are derived from weathering of silicate detritus. However, calcretes from a fan draining a carbonate terrane have strontium compositions dominated locally by the limestone strontium component. Although much evidence points to an eolian source for at least some of the strontium in the pedogenic carbonates near Yucca Mountain, an additional component or past variation of strontium composition in the eolian source is required to model the pedogenic carbonate system

Influence of Tm-doping on microstructure and luminescence behavior of barium strontium titanate thick films

International Nuclear Information System (INIS)

Wang Jingyang; Zhang Tianjin; Pan Ruikun; Ma Zhijun; Wang Jinzhao

2012-01-01

Tm-doped Ba 0.8 Sr 0.2 TiO 3 thick films were prepared by the screen-printing technique on the alumina substrate. The microstructure of the Tm-doped BST thick films was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman spectroscopy, respectively. All the samples showed a typical perovskite polycrystalline structure when sintered at 1260 °C. The substitution behavior of Tm 3+ ion in BST was found to change with increasing the Tm 3+ concentration. The observed Tm-related red emission reaches the maximum at 0.2 mol% Tm 3+ concentration. The effects of concentration quenching on the luminescence intensity were discussed.

Multifunction Sr, Co and F co-doped microporous coating on titanium of antibacterial, angiogenic and osteogenic activities

OpenAIRE

Jianhong Zhou; Lingzhou Zhao

2016-01-01

Advanced multifunction titanium (Ti) based bone implant with antibacterial, angiogenic and osteogenic activities is stringently needed in clinic, which may be accomplished via incorporation of proper inorganic bioactive elements. In this work, microporous TiO2/calcium-phosphate coating on Ti doped with strontium, cobalt and fluorine (SCF-TiCP) was developed, which had a hierarchical micro/nano-structure with a microporous structure evenly covered with nano-grains. SCF-TiCP greatly inhibited t...

Organic composite-mediated surface coating of human acellular bone matrix with strontium.

Science.gov (United States)

Huang, Yi-Zhou; Wang, Jing-Jing; Huang, Yong-Can; Wu, Cheng-Guang; Zhang, Yi; Zhang, Chao-Liang; Bai, Lin; Xie, Hui-Qi; Li, Zhao-Yang; Deng, Li

2018-03-01

Acellular bone matrix (ACBM) provides an osteoconductive scaffold for bone repair, but its osteoinductivity is poor. Strontium (Sr) improves the osteoinductivity of bone implants. In this study, we developed an organic composite-mediated strontium coating strategy for ACBM scaffolds by using the ion chelating ability of carboxymethyl cellulose (CMC) and the surface adhesion ability of dopamine (DOPA). The organic coating composite, termed the CMC-DOPA-Sr composite, was synthesized under a mild condition, and its chemical structure and strontium ion chelating ability were then determined. After surface decoration, the physicochemical properties of the strontium-coated ACBM (ACBM-Sr) scaffolds were characterized, and their biocompatibility and osteoinductivity were determined in vitro and in vivo. The results showed that the CMC-DOPA-Sr composite facilitated strontium coating on the surface of ACBM scaffolds. The ACBM-Sr scaffolds possessed a sustained strontium ion release profile, exhibited good cytocompatibility, and enhanced the osteogenic differentiation of mesenchymal stem cells in vitro. Furthermore, the ACBM-Sr scaffolds showed good histocompatibility after subcutaneous implantation in nude mice. Taken together, this study provided a simple and mild strategy to realize strontium coating for ACBM scaffolds, which resulted in good biocompatibility and improved osteoinductivity. Copyright © 2017 Elsevier B.V. All rights reserved.

Strontium and fluorine in tuatua shells

International Nuclear Information System (INIS)

Trompetter, W.J.; Coote, G.E.

1993-01-01

This report describes the research to date on the elemental distributions of strontium, calcium, and fluorine in a collection of 24 tuatua shells (courtesy of National Museum). Variations in elemental concentrations were measured in the shell cross-sections using a scanning proton microprobe (PIXE and PIGME). In this paper we report the findings to date, and present 2-D measurement scans as illustrative grey-scale pictures. Our results support the hypothesis that increased strontium concentrations are deposited in the shells during spawning, and that fluorine concentration is proportional to growth rate. (author). 15 refs.; 13 figs.; 1 appendix

Dosing of low-activity strontium 90 in human bone ashes - A method based on the quantitative precipitation of strontium nitrate

International Nuclear Information System (INIS)

Patti, Francois; Bullier, Denise

1969-02-01

The specific separation of strontium nitrate in bone ash samples by red fuming nitric acid requires a succession of precipitation varying in number according to the weight of ashes. The interest of the technique is to define the experimental conditions required for a reproducible quantitative separation of strontium. The operating process tested on over 1.500 samples allowed to obtain chemical yields of about 90 per cent. (authors) [fr

Strontium-90 and cesium-137 in freshwater from May 1984

International Nuclear Information System (INIS)

1984-01-01

Strontium-90 and cesium-137 in freshwater measured in May 1984 are given in pCi/l. The sampling point is 1, Kasumigaura-Lake (Ibaraki). Collection and pretreatment of samples, preparation of samples for analysis, separation of strontium-90 and cesium-137, determination of stable strontium, calcium and potassium, and counting are described. The sample was passed through a cation exchange column. After the radiochemical separation, the mounted precipitates were counted for activity using low background beta counters normally for 60 minutes. (Mori, K.)

Bactericidal strontium-releasing injectable bone cements based on bioactive glasses

OpenAIRE

Brauer, Delia S.; Karpukhina, Natalia; Kedia, Gopal; Bhat, Aditya; Law, Robert V.; Radecka, Izabela; Hill, Robert G.

2013-01-01

Strontium-releasing injectable bone cements may have the potential to prevent implant-related infections through the bactericidal action of strontium, while enhancing bone formation in patients suffering from osteoporosis. A melt-derived bioactive glass (BG) series (SiO2–CaO–CaF2–MgO) with 0–50% of calcium substituted with strontium on a molar base were produced. By mixing glass powder, poly(acrylic acid) and water, cements were obtained which can be delivered by injection and set in situ, gi...

Decomposition pathways of polytetrafluoroethylene by co-grinding with strontium/calcium oxides.

Science.gov (United States)

Qu, Jun; He, Xiaoman; Zhang, Qiwu; Liu, Xinzhong; Saito, Fumio

2017-06-01

Waste polytetrafluoroethylene (PTFE) could be easily decomposed by co-grinding with inorganic additive such as strontium oxide (SrO), strontium peroxide (SrO 2 ) and calcium oxide (CaO) by using a planetary ball mill, in which the fluorine was transformed into nontoxic inorganic fluoride salts such as strontium fluoride (SrF 2 ) or calcium fluoride (CaF 2 ). Depending on the kind of additive as well as the added molar ratio, however, the reaction mechanism of the decomposition was found to change, with different compositions of carbon compounds formed. CO gas, the mixture of strontium carbonate (SrCO 3 ) and carbon, only SrCO 3 were obtained as reaction products respectively with equimolar SrO, excess SrO and excess SrO 2 to the monomer unit CF 2 of PTFE were used. Excess amount of CaO was needed to effectively decompose PTFE because of its lower reactivity compared with strontium oxide, but it promised practical applications due to its low cost.

Strontium Diibuprofenate Dihydrate, Strontium Malonate Sesquihydrate, Strontium Diascorbate Dihydrate and Strontium 2-Oxidobenzoate Hydrate at 120 K

DEFF Research Database (Denmark)

Stahl, Kenny; Andersen, Jens Enevold Thaulov; Cristgau, Stephan

2006-01-01

-sharing to form chains. The Sr coordination chains are packed into layers, which are stacked by van der Waals interactions. Poly[-aqua-diaquadi--malonato-distrontium(II)], [Sr2(C3H2O4)2(H2O)3]n, crystallizes with nine-coordinated Sr atoms three-dimensionally interconnected into a framework structure. One...... of the two crystallographically independent water molecules is located on a twofold axial site. catena-Poly[[diaqua(ascorbato)strontium(II)]--ascorbato], [Sr(C6H7O6)2(H2O)2]n, crystallizes with isolated eight-coordinated Sr polyhedra. One of the ascorbate ligands bridges two Sr atoms, forming zigzag...

Measurements of cesium and strontium diffusion in biotite gneiss

International Nuclear Information System (INIS)

Skagius, K.; Neretnieks, I.

1988-01-01

A significant retardation of radionuclides transported by flowing water from an underground repository can be expected if the nuclides are able to diffuse into the water filled micropores in the rock. This diffusion into the pores will also increase the surface available to interactions between the nuclides in the ground water and the rock material, such as sorption. To calculate the retardation, it is necessary to know the sorption properties and the diffusivities in the rock matrix for the radionuclides. Diffusion experiments with cesium and strontium in biotite gneiss samples have been performed. Both the transport of strontium and cesium through rock samples and the concentration profiles of cesium and strontium inside rock samples have been determined. The result shows that diffusion of cesium and strontium occurs in the rock material. A diffusion model has been used to evaluate the diffusivity. Both pore diffusion and surface diffusion had to be included in the model to give good agreement with the experimental data. If surface diffusion is not included in the model, the effective pore diffusivity that gives the best fit to the experimental data is found to be higher than expected from earlier measurement of iodide diffusion in the same type of rock material. This indicates that the diffusion of cesium and strontium (sorbing components) in rock material is caused by both pore diffusion and surface diffusion acting in parallel

Diffusion measurements of cesium and strontium in biotite gneiss

International Nuclear Information System (INIS)

Skagius, K.; Neretnieks, I.

1985-01-01

A significant retardation of radionuclides transported by flowing water from an underground repository can be expected if the nuclides are able to diffuse into the water filled micropores in the rock. This diffusion into the pores will also increase the surface available to interaction between the nuclides in the groundwater and the rock material, such as sorption. To calculate the retardation it is necessary to know the sorption properties and the diffusivities in the rock matrix for the radionuclides. Diffusion experiments with cesium and strontium in biotite gneiss samples have been performed. Both the transport of strontium and cesium through rock samples and the concentration profiles of cesium and strontium inside rock samples have been determined. The result show that diffusion of cesium and strontium occurs in the rock material. A diffusion model has been used to evaluate the diffusivity. Both pore diffusion and surface diffusion had to be included in the model to give good agreement with the experimental data. If surface diffusion is not included in the model, the effective pore diffusivity that gives the best fit to the experimental data is found to be higher than expected from earlier measurements of iodide diffusion in the same type of rock material. This indicates that the diffusion of cesium and strontium (sorbing components) in rock material is caused by both pore diffusion and surface diffusion acting in parallel. (author)

The inhibitory effect of strontium-doped calcium polyphosphate particles on cytokines from macrophages and osteoblasts leading to aseptic loosening in vitro

International Nuclear Information System (INIS)

Huang, Chengcheng; Yu, Xixun; Gu, Zhipeng; Li, Li; Zhang, Xu

2014-01-01

Aseptic loosening is a common cause of joint implant failure in humans. In order to enhance implant stability, we need to develop a new material that not only promotes the wear resistance of components of an artificial joint, but also possesses the pharmaceutical efficacy of protecting patients against aseptic loosening. Strontium-doped calcium polyphosphate (SCPP) has been found to have this potential ability. The goal of this study is to respectively quantify the levels of TNF-α (for macrophages), receptor activator of NF- k B ligand (RANKL) and osteoprotegerin (OPG) (for osteoblasts) when osteoblasts and macrophages are challenged with various particles (including SCPP). In this study, the osteoblasts ROS 17/2.8 and macrophages RAW 264.7 were challenged with various wear particles (8% SCPP, the molar percentage of Sr in SCPP is 8%, UHMWPE, hydroxyapatite (HA) and CPP). The secretion of TNF-α (from RAW 264.7), OPG and RANKL protein (from ROS 17/2.8) was analyzed by ELISA. The OPG and RANKL mRNA from ROS 17/2.8 was detected by RT-PCR. The data of ELISA indicated that the amount of TNF-α challenged with 8% SCPP particles was more than three-fold lower than that of all other test groups. The ratio of OPG/RANKL in the 8% SCPP group was significantly increased compared to that of all other test groups. The results of OPG and RANKL mRNA expression showed the same tendency as the ELISA results. In general, this study showed that 8% SCPP particles can inhibit the expression of TNF-α and RANKL, promote the expression of OPG so that SCPP can inhibit bone resorption and promote bone formation, and then inhibit aseptic loosening. Thus SCPP could be a promising material for the construction of artificial joints. (paper)

Positron annihilation study of strontium doped YBa2Cu3Osub(7-δ) superconductors

International Nuclear Information System (INIS)

Huang, W.F.; Ouseph, P.J.; Fang, K.; Xu, Z.J.

1988-01-01

Doppler broadened lineshapes of the gamma lines from positron annihilation in Y(Basub(2-x) Srsub(x))Cu 3 )Osub(7-δ) superconductors were measured with x = 0.0 to 1.2. Results are indicative of additional oxygen vacancies introduced by doping. (author)

Study of retention properties of fluoro-apatite carbonate relative to Ni(II), Am(III) and Th(IV); Etude des proprietes de retention des carbonate fluoroapatites vis-a-vis de Ni(II), Am(III) et Th(IV)

Energy Technology Data Exchange (ETDEWEB)

Perrone, Jane [Inst. de Physique Nucleaire, Paris-11 Univ., 91 - Orsay (France)

1999-07-12

Apatite minerals and particularly the carbonated species (francolites), are characterized by their chemical and geological stability and also by their capacity to retain durably a large number of elements. Therefore, they should be able to improve the retention properties of the engineered barriers of a deep geological nuclear waste repository. But there is a wide variety of francolites, so we focused our study on a synthetic carbonate fluoro-apatite of formula: Ca{sub 10}(PO{sub 4}){sub 5}(CO{sub 3})(F,OH){sub 3} and on a natural apatite. We first studied their solubility which is an important criterion for the choice of the materials. A particular attention was also paid to the determination of their surface characteristics and to the study of the radionuclide/solution interactions. Sorption experiments have been performed for the three radionuclides and the influence of various parameters has been investigated. The modelling of the sorption isotherms with surface complexation models leads us to estimate the values of the constants associated to the equilibria under consideration. We have also demonstrated that the phosphate ions of the solution participate to the immobilization of americium as the AmPO{sub 4},xH{sub 2}O compound. Both apatites show high retention levels for the actinides: the sorption is quite total over all the pH range studied and the Kd values are close to 10{sup 4} m{sup 3} kg{sup -1}. Consequently, the use of apatites could be considered as a specific solution for the immobilisation of heavy elements, specially actinides. Moreover, the results indicate that high amounts of carbonates and impurities do not alter the retention properties of francolites. This bears out the feasibility of the use of natural apatites as additives for the engineered barrier materials. (author)

Thermal reactions of some calcium, strontium, and barium chromates

International Nuclear Information System (INIS)

Piekarska-Piesse, B.; Gontarz, Z.; Ostrowski, A.; Kucharski, R.

2000-01-01

Thermal decomposition of calcium chromates and solid state reactions of barium and strontium chromates(VI) with barium and strontium hydroxides and carbonates, as well as the reduction of chromates by carbon and hydrogen, have been investigated. The mechanisms of individual stages of the thermal decomposition have been proposed on the basis of morphological classification. (author)

Strontium-90 - ED 4309

International Nuclear Information System (INIS)

Ammerich, M.; Frot, P.; Gambini, D.; Gauron, C.; Moureaux, P.; Herbelet, G.; Lahaye, T.; Le Guen, B.; Pihet, P.; Rannou, A.; Vidal, E.

2012-12-01

This sheet presents the characteristics of strontium-90, its origin, and its radio-physical and biological properties. It briefly describes its use in nuclear medicine. It indicates its dosimetric parameters for external exposure, cutaneous contamination, and internal exposure due to acute contamination or to chronic contamination. It indicates and comments the various exposure control techniques: ambient dose rate measurement, surface contamination measurement, atmosphere contamination. It addresses the means of protection: premise design, protection against external exposure and against internal exposure. It describes how areas are delimited and controlled within the premises: regulatory areas, controls to be performed. It addresses the personnel classification, training and medical survey. It addresses the issue of wastes and effluents. It briefly recalls the administrative procedures related to the authorization and declaration of possession and use of sealed and unsealed sources. It indicates regulatory aspects related to the transport of strontium-90, describes what is to be done in case of incident or accident (for the different types of contamination or exposure)

Strontium effects on root dentin tubule occlusion and nanomechanical properties.

Science.gov (United States)

Saeki, Kuniko; Marshall, Grayson W; Gansky, Stuart A; Parkinson, Charles R; Marshall, Sally J

2016-02-01

Dentin hypersensitivity often is treated by promotion of dentin tubule occlusion. In this in vitro study we evaluated nanomechanical properties and degree of tubule occlusion conferred to sound and demineralized human root dentin following treatment with a 10% (w/w) strontium acetate solution and its relation to the treatment duration and delivery method. 24 human cervical root dentin disks (8 groups of 3) were polished through 0.25 μm. 12 disks were subjected to an acid challenge (1% citric acid, pH 3.8) for 2 min. The specimens were incubated in artificial saliva, treated by soaking or brushing with deionized (DI) water or a solution of 10% strontium acetate for 2 min twice a day for 28 days. The occlusion percent and nanomechanical properties were determined at the baseline, 5, 14 and 28 days. Cross-sectioned specimens were prepared to evaluate the depth affected by strontium acetate / dentin interaction by SEM. Statistical analysis was performed using linear mixed effects models. A 10% strontium acetate treatment over 5-28 days significantly increased tubule occlusion for normal root dentin and to a lesser extent for demineralized dentin and increased the AFM based nanomechanical properties of demineralized dentin. Brushing was more effective than soaking in recovery of properties of demineralized dentin when treated with strontium. No difference in tubuleocclusion was found between the two delivery methods. Strontium acetate itself proved to have the ability to occlude dentin tubules and result in small changes in the mechanical properties of dentin. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Induction of a program gene expression during osteoblast differentiation with strontium ranelate

International Nuclear Information System (INIS)

Zhu Lingling; Zaidi, Samir; Peng Yuanzhen; Zhou Hang; Moonga, Baljit S.; Blesius, Alexia; Dupin-Roger, Isabelle; Zaidi, Mone; Sun Li

2007-01-01

Strontium ranelate, a new agent for the treatment of osteoporosis, has been shown stimulate bone formation in various experimental models. This study examines the effect of strontium ranelate on gene expression in osteoblasts, as well as the formation of mineralized (von Kossa-positive) colony-forming unit-osteoblasts (CFU-obs). Bone marrow-derived stromal cells cultured for 21 days under differentiating conditions, when exposed to strontium ranelate, displayed a significant time- and concentration-dependent increase in the expression of the master gene, Runx2, as well as bone sialoprotein (BSP), but interestingly without effects on osteocalcin. This was associated with a significant increase in the formation of CFU-obs at day 21 of culture. In U-33 pre-osteoblastic cells, strontium ranelate significantly enhanced the expression of Runx2 and osteocalcin, but not BSP. Late, more mature osteoblastic OB-6 cells showed significant elevations in BSP and osteocalcin, but with only minimal effects on Runx2. In conclusion, strontium ranelate stimulates osteoblast differentiation, but the induction of the program of gene expression appears to be cell type-specific. The increased osteoblastic differentiation is the likely basis underlying the therapeutic bone-forming actions of strontium ranelate

Crystallization of carbonate hydroxyapatite in the presence of strontium ranelate

Science.gov (United States)

Izmailov, R. R.; Golovanova, O. A.

2015-11-01

The influence of strontium ranelate on the crystallization of carbonate hydroxyapatite from a prototype of synovial fluid of humans has been investigated. The synthesis products are studied by IR Fourier spectroscopy, X-ray diffraction, and differential thermal analysis. The amount of strontium in the samples is determined by atomic emission analysis. The sizes of crystallites in the synthesized phases are calculated from the Selyakov-Scherrer formula; the lattice parameters are also determined. The phases obtained are found to be species of calcium-deficient strontium-containing carbonate hydroxyapatite of mixed A and B types. Schemes of chemical reactions occurring during heat treatment are proposed.

A novel design of anode-supported solid oxide fuel cells with Y{sub 2}O{sub 3}-doped Bi{sub 2}O{sub 3}, LaGaO{sub 3} and La-doped CeO{sub 2} trilayer electrolyte

Energy Technology Data Exchange (ETDEWEB)

Guo, Weimin [School of Chemistry and Engineering, South China University of Technology, The Key Laboratory of Enhanced Heat Transfer and Energy Conservation, Ministry of Education, Guangzhou 510640 (China); Department of Biological and Chemical Engineering, Guangxi University of Technology, Liuzhou 545006 (China); Liu, Jiang [School of Chemistry and Engineering, South China University of Technology, The Key Laboratory of Enhanced Heat Transfer and Energy Conservation, Ministry of Education, Guangzhou 510640 (China)

2010-12-15

Anode-supported solid oxide fuel cells (SOFCs) with a trilayered yttria-doped bismuth oxide (YDB), strontium- and magnesium-doped lanthanum gallate (LSGM) and lanthanum-doped ceria (LDC) composite electrolyte film are developed. The cell with a YDB (18 {mu}m)/LSGM (19 {mu}m)/LDC (13 {mu}m) composite electrolyte film (designated as cell-A) shows the open-circuit voltages (OCVs) slightly higher than that of a cell with an LSGM (31 {mu}m)/LDC (17 {mu}m) electrolyte film (designated as cell-B) in the operating temperature range of 500-700 C. The cell-A using Ag-YDB composition as cathode exhibits lower polarization resistance and ohmic resistance than those of a cell-B at 700 C. The results show that the introduction of YDB to an anode-supported SOFC with a LSGM/LDC composite electrolyte film can effectively block electronic transport through the cell and thus increased the OCVs, and can help the cell to achieve higher power output. (author)

Simplified method for the determination of strontium-90 in large amounts of bone-ash; Methode simplifiee de dosage du strontium 90 sur des quantites importantes de cendres d'os

Energy Technology Data Exchange (ETDEWEB)

Patti, F; Jeanmaire, L [Commissariat a l' Energie Atomique, Fontenay-aux-roses (France). Centre d' Etudes Nucleaires

1966-06-01

The principle of the determination is based on a 3-step process: 1) concentrating the strontium by attacking the ash with nitric acid; 2) elimination of residual phosphoric ions by a double precipitation of strontium oxalate; and 3) extraction of yttrium 90, counted in the oxalate form. The advantages of the method: -) using simple techniques it makes it possible to process 50 g of ash; -) the initial concentration of strontium considerably reduces the volume of the solutions as well as the size of precipitates handled. Fuming nitric acid is used in a specially designed burette. (authors) [French] Le principe du dosage repos sur un procede en 3 etapes: 1) Concentration du strontium par une attaque nitrique des cendres; 2) Elimination des ions phosphoriques restants par une double precipitation de l'oxalate de strontium. 3) Extraction de l'yttrium 90, compte sous forme d'oxalate. Interet de la methode: dans des conditions techniques simples, elle permet le traitement de 50 g de cendres d'os; la concentration initiale du strontium reduit notablement le volume des solutions ainsi que l'importance des precipites manipules. L'acide nitrique fumant est utilise par l'intermediaire d'une burette specialement concue a cet effet.

Processing of strontium-doped lanthanum manganite suspensions for cathode production of the solid oxide fuel cell; Processamento das suspensoes de manganito de lantanio dopado com estroncio para fabricacao do catodo da celula a combustivel de oxido solido

Energy Technology Data Exchange (ETDEWEB)

Chiba, R.; Vargas, R.A.; Andreoli, M.; Seo, E.S.M. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Ciencia e Tecnologia de Materiais. Lab. de SOFC - Insumos e Componentes

2008-07-01

The ceramic material, strontium-doped lanthanum manganite (La{sub 0,85}Sr{sub 0,15}MnO{sub 3} - LSM), has been used as cathode in Solid Oxide Fuel Cells (SOFCs). The cathode attainment as component of the SOFCs has been studied for diverse routes of synthesis and thin films forming in Yttria-stabilized zirconia (ZrO{sub 2}/Y{sub 2}O{sub 3} - YSZ) electrolyte. In this work, the LSM was synthesized by the citrate technique and deposited in YSZ substrate using the forming technique wet powder spraying. Rheological studies of suspensions and chemical, physical and microstructural characterizations of LSM powders were made, aiming at the deposition for thin films formation until 50 mum. The half unit cells LSM/YSZ sintered were characterized by scanning electron microscopy, for verification of porosity and adherence. In this sense, this work is a contribution for production of porous cathode using the forming technique wet powder spraying in the SOFCs. (author)

Preparation of strontium hexaferrite magnets from celestite and blue dust by mechanochemical route

Directory of Open Access Journals (Sweden)

Tiwary R.K.

2008-01-01

Full Text Available In the present investigation celestite (natural ore of strontium and blue dust (iron ore fines have been used for the preparation of strontium hexaferrite powder. The mechanical alloying process has been adopted to prepare strontium hexaferrite powder. The celestite after chemical upradation and physically upgraded blue dust alongwith sodium carbonate was taken for the preparation of strontium hexaferrite in this experiment. The high-energy planetary ball mill with tungsten carbide jar and ball was used to prepare strontium hexaferrite powder. A long time of ball milling for different duration has led to displacement solid-state reaction. At the end of each experiment the product was washed thoroughly and dried. The X-ray diffaction study after annealing shows the development of single-phase strontium hexaferrite after 40 hrs. of milling. The resultant powder was compacted under magnetic field and sintered to prepare the magnet after annealing the ferrite powder. The magnetic properties were measured by Pulse magneto meter. The moderate value of coercivity, remanence and energy product were observed in this sintered magnet. The work illustrates the feasibility to prepare strontium hexaferrite magnetic powders directly from natural ores which can reduce the total cost of production as compared to conventional method.

Study of strontium and cesium migration in fractured crystalline rock

International Nuclear Information System (INIS)

Gustafsson, E.; Klockars, C.E.

1984-01-01

The purpose of this investigation has been to study the retardation and dilution of non-active strontium and cesium relative to a non-absorbing substance (iodide) in a well-defined fracture zone in the Finnsjoen field research area. The investigation was carried out in a previously tracer-tested fracture zone. The study has encompassed two separate test runs with prolonged injection of strontium and iodide and of cesium and iodide. The test have shown that: - Strontium is not retarded, but rather absorbed to about 40% at equilibrium. - At injection stop, 36.3% of the injected mass of strontium has been absorbed and there is no deabsorption. -Cesium is retarded a factor of 2-3 and absorbed to about 30% at equilibrium. - At injection stop, 39.4% of the injected mass of cesium has been absorbed. Cesium is deabsorbed after injection stop (400h) and after 1300 hours, only 22% of the injected mass of cesium is absorbed. (author)

Atomization of magnesium, strontium, barium and lead nitrates on surface of graphite atomizers

International Nuclear Information System (INIS)

Nagdaev, V.K.; Pupyshev, A.A.

1982-01-01

Modelling of the processes on graphite surface using differential-thermal analysis and graphite core with identification of decomposition products of magnesium, strontium, barium and lead nitrates by X-ray analysis has shown that carbon promotes the formation of strontium, barium and lead carbonates. The obtained temperatures of strontium and barium carbonate decomposition to oxides agree satisfactorily with calculation ones. Magnesium nitrate does not react with carbon. Formation of strontium and barium carbonates results in considerable slowing down of the process of gaseous oxide dissociation. Lead carbonate is unstable and rapidly decomposes to oxide with subsequent reduction to free metal. Formation of magnesium, strontium and barium free atoms is connected with appearance of gaseous oxides in analytical zone. Oxide and free metal lead are present on graphite surface simultaneously

Luminescence life time and time-resolved spectroscopy of Cr3+ ions in strontium barium niobate

International Nuclear Information System (INIS)

Han, T.P.J.; Jaque, F.; Jaque, D.; Garcia-Sole, J.; Ivleva, L.

2006-01-01

This paper reports on the photo-luminescence spectroscopic results of congruent strontium-barium-niobate (SBN) crystals doped with Cr 2 O, at cryogenic temperature (20 K). The experimental results reveal the need of re-assignment of the Cr 3+ ions defect centres in this material. For first time, a broad emission band in the near infrared region centred at ca. 950 nm is reported. This emission band has micro-seconds decaytime constant and a band-width full-width at half-maximum (FWHM) larger than 1700 cm -1 and has been ascribed to the vibronically assisted 4 T 2 →4 A 2 transition. A much narrower emission band centred at ca. 764 nm with milli-seconds decaytime constant and a FWHM band-width of ca. 170 cm -1 is correlated to the 2 E →4 A 2 radiative transition (R-line)

Redistribution of strontium and cesium during alteration of smectite to illite

International Nuclear Information System (INIS)

Ohnuki, Toshihiko; Murakami, Takashi; Sato, Tsutomu; Isobe, Hiroshi

1994-01-01

The redistribution of strontium and cesium during the alteration of smectite to illite has been studied under hydrothermal conditions at 200 C using solutions of 1x10 -4 M Sr and Cs. Two different sorption conditions were applied for the hydrothermal experiments. One was the condition in which strontium and cesium were sorbed by smectite before the hydrothermal experiments (dynamic condition). The other was the condition in which strontium and cesium were sorbed by the alteration products, illite/smectite (I/S) interstratified minerals after the hydrothermal experiments (static condition). The sorption characteristics of strontium and cesium by smectite, I/S interstratified minerals were examined by a sequential extraction method. Most of the strontium was desorbed from smectite and the I/S interstratified minerals with a 1 M KCl solution under both the dynamic and static conditions. Less than 1% of cesium was desorbed from the I/S interstratified minerals with any solution of a 1 M KCl, a 1 M HCl and a 6 M HCl under the dynamic condition, while most of cesium was desorbed with either solution of a 1 M KCl and 1 M HCl from smectite and from the I/S interstratified minerals under the static condition. These suggest that cesium sorbed by smectite changes its sorption characteristic during the alteration process, but strontium does not. Possible sites for more strongly bounded cesium to the I/S interstratified minerals may be at the 'ditrigonal cavity' of adjacent tetrahedral layers. (orig.)

Baseline concentrations of strontium and 90Sr in seawater from the northern Gulf

International Nuclear Information System (INIS)

Uddin, S.; Al Ghadban, A.N.; Behbahani, M.

2013-01-01

Highlights: • This is the first baseline for strontium and 90 Sr from northern Gulf. • The total strontium concentration is much higher than reported for other oceans. • The Sr/salinity ratio correlates well with global averages. • High Sr might be due to increased salinity/CaCo 3 dissolution in acidifying Gulf waters. -- Abstract: Baseline concentration of strontium and Sr-90 in Gulf is presented. The strontium concentration is much higher than reported for other oceanic waters, while the Sr-90 concentration is low at 0.7–1.0 mBq l −1 , that represents the background level following nuclear tests and can be used as an effective tracer in case of any radioactive release in the region. The strontium concentration is primarily related to the increasing salinity off the Gulf coast

Isotope ratios of strontium and neodymium for characterizing earth mantle materials

International Nuclear Information System (INIS)

Brandt, S.B.; Lepin, V.S.; Maslovskaja, M.N.

1985-01-01

It is shown that the shares of mantle, crustal and sedimentary materials in rocks and ore deposits can be determined by isotope methods. Using Yakutian kimberlites as an example, mixing processes of mantle and crustal materials are illustrated with the aid of strontium isotopes. Due to the high sensitivity of strontium to hydrothermal effects, the combined use of neodymium and strontium isotopes is considered more appropriate to solve the problem of determining the share of mantle materials. This is demonstrated for rare earth minerals and alkaline rocks of Eastern Siberia and Mongolia. (author)

Biosorption of the strontium ion by irradiated Saccharomyces cerevisiae under culture conditions.

Science.gov (United States)

Qiu, Liang; Feng, Jundong; Dai, Yaodong; Chang, Shuquan

2017-06-01

As a new-emerging method for strontium disposal, biosorption has shown advantages such as high sorption capacity; low cost. In this study, we investigated the potential of Saccharomyces cerevisiae (S. cerevisiae) in strontium disposal under culture conditions and the effects of irradiation on their biosorption capabilities. We found that S. cerevisiae can survive irradiation and grow. Pre-exposure to irradiation rendered S. cerevisiae resistant to further irradiation. Surprisingly, the pre-exposure to irradiation can increase the biosorption capability of S. cerevisiae. We further investigated the factors that influenced the biosorption efficiency, which were (strongest to weakest): pH > strontium concentration > time > temperature. In our orthogonal experiment, the optimal conditions for strontium biosorption by irradiated S. cerevisiae were: pH 7, 150 mg L -1 strontium at the temperature of 32 °C with 30 h. The equilibrium of strontium biosorption was analyzed by Langmuir and Freundlich models, from which the formal model is found to provide a better fit for the experimental results. The kinetics of strontium biosorption by living irradiated S. cerevisiae was found to be comprised of three phases: dramatically increased during 0-9 h, decreased during 12-24 h, and increased during 30-50 h. These results provide a systematic understanding of the biosorption capabilities of irradiated S. cerevisiae, which can contribute to the development of remediating nuclear waste water. Copyright © 2017 Elsevier Ltd. All rights reserved.

Accumulation of strontium 90 and cesium 137 in some hydrobionts

International Nuclear Information System (INIS)

Boyadzhiev, A.; Keslev, D.; Kerteva, A.; Novakova, E.

1974-01-01

Factors responsible for the accumulation of strontium 90 and cesium 137 in some plant organisms, characteristic for fishes in Bulgarian fresh-water reservoirs and in Black Seawater, were examined. The investigated samples were taken during spring, summer and autumn-winter seasons 1967/1968. Each sample burnt to ashes at 450 0 C was examined for strontium 90 and cesium 137 content as well as stable isotopes of calcuim and potassium. Accumulation factors for strontium 90 and cesium 137 were significantly higher in freshwater hydrobionts than in seawater hydrobionts. This could be explained by variations in the concentration of stable isotopes of calcium and potassium from freshwater reservoirs and from seawater. Potassium and calcium concentrations were relatively constant in seawater while in freshwater they were significantly variable. Accumulation factors for these radionuclides increased according to the amount of rain and the altitude above sea level. Strontium 90 was deposited mostly in fins, less in scales and least in the meat of fishes; cesium 137 was mainly deposited in the meat and less in the other parts of fishes. The highest accumulation factors for strontium 90 were determined in fishes and for cesium 137 in plant organisms. The most convenient plant and fish species for tracing radioactive contamination of freshwater reservoirs and in the Black Sea were indicated. (A.B.)

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.

Dissolved strontium and calcium levels in the tropical Indian Ocean

Science.gov (United States)

Steiner, Zvi; Sarkar, Amit; Turchyn, Alexandra

2017-04-01

Measurements of seawater alkalinity and dissolved calcium concentrations along oceanic transects are often used to calculate calcium carbonate precipitation and dissolution rates. Given that the distribution coefficient of strontium in CaCO3 varies greatly between different groups of organisms, adding precise measurements of dissolved strontium concentrations provides opportunities to also track relative contributions of these different groups to the regional CaCO3 cycle. However, there are several obstacles to this approach. These obstacles include unresolved systematic discrepancies between seawater calcium and alkalinity data, very large analytical noise around the calcium concentration measurements and the unconstrained role of acantharia (radiolarian precipitating SrSO4 skeletons) in the marine strontium cycle. During the first cruise of the second International Indian Ocean Expedition (IIOE-2) water samples were collected along 67°E from 9°N to 5°S to explore the dissolution rate of calcium carbonate in the water. The dissolution rate can be calculated by combining measurements of water column potential alkalinity with calcium and strontium concentrations measured by ICP-OES and calcium concentration measurements using isotope dilution thermal ionization mass spectrometry (ID-TIMS). CaCO3 mineral saturation state calculated using pH and total alkalinity suggests that along 67°E, the aragonite saturation horizon lays at depth of 500 m on both sides of the equator. Across the cruise transect, dissolved strontium concentrations increase by 2-3% along the thermocline suggesting rapid recycling of strontium rich phases. This is particularly evident just below the thermocline at 8-9°N and below 1000 m water depth, south of the equator. The deep, southern enrichment in strontium does not involve a change in the Sr/Ca ratio, suggesting that this strontium enrichment is related to CaCO3 dissolution. In contrast, in the intermediate waters of the northern part of

Processing/structure/property Relationships of Barium Strontium Titanate Thin Films for Dynamic Random Access Memory Application.

Science.gov (United States)

Peng, Cheng-Jien

The purpose of this study is to see the application feasibility of barium strontium titanate (BST) thin films on ultra large scale integration (ULSI) dynamic random access memory (DRAM) capacitors through the understanding of the relationships among processing, structure and electrical properties. Thin films of BST were deposited by multi-ion -beam reactive sputtering (MIBERS) technique and metallo -organic decomposition (MOD) method. The processing parameters such as Ba/Sr ratio, substrate temperature, annealing temperature and time, film thickness and doping concentration were correlated with the structure and electric properties of the films. Some effects of secondary low-energy oxygen ion bombardment were also examined. Microstructures of BST thin films could be classified into two types: (a) Type I structures, with multi-grains through the film thickness, for amorphous as-grown films after high temperature annealing, and (b) columnar structure (Type II) which remained even after high temperature annealing, for well-crystallized films deposited at high substrate temperatures. Type I films showed Curie-von Schweidler response, while Type II films showed Debted type behavior. Type I behavior may be attributed to the presence of a high density of disordered grain boundaries. Two types of current -voltage characteristics could be seen in non-bombarded films depending on the chemistry of the films (doped or undoped) and substrate temperature during deposition. Only the MIBERS films doped with high donor concentration and deposited at high substrate temperature showed space-charge -limited conduction (SCLC) with discrete shallow traps embedded in trap-distributed background at high electric field. All other non-bombarded films, including MOD films, showed trap-distributed SCLC behavior with a slope of {~}7.5-10 due to the presence of grain boundaries through film thickness or traps induced by unavoidable acceptor impurities in the films. Donor-doping could

Determination of the exchange capacity of soils using radio-strontium; Determination de la capacite d'echange des sols au moyen du radio-strontium

Energy Technology Data Exchange (ETDEWEB)

Grauby, A; Saas, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-07-01

In order to improve the technique and in particular to reduce the time required for measuring the exchange capacity of soils, the authors have developed a rapid measurement method based on the use of radio-active tracers. The element chosen for showing the occurrence of exchangeable bases is radio-strontium; it can displace the ions Ca{sup ++}, Mg{sup ++}, Na{sup ++}, K{sup +} from the soil. The use of a de-sorbent, barium chloride, makes it possible to recover the strontium fixed. A comparison of the results obtained using the two methods appears to be very satisfactory. The conventional method requires from 1 1/2 to 2 days - the radio-strontium method requires only 3 hours with the possibility also of carrying out large series of measurements. (authors) [French] Pour ameliorer la technique et surtout reduire le temps de manipulation que necessite la mesure de la capacite d'echange des sols, les auteurs ont mis au point une methode de mesure rapide qui fait appel aux traceurs radioactifs. C'est le radio-strontium qui a ete choisi pour la mise en evidence des bases echangeables. Il permet de deplacer les ions Ca{sup ++}, Mg{sup ++}, Na{sup ++}, K{sup +} du sol. Un desorbant, le chlorure de baryum, permet de recuperer la quantite du strontium fixe. La comparaison des resultats obtenus par les deux methodes semble tres satisfaisante. La methode classique necessite 1 jour et demi a 2 jours - la methode radiostrontium exige seulement 3 heures avec la possibilite de grandes series. (auteurs)

Metastable equilibrium solubility behavior of carbonated apatite in the presence of solution strontium.

Science.gov (United States)

Heslop, D D; Bi, Y; Baig, A A; Higuchi, W I

2004-01-01

The purpose of this study was to use the concept of metastable equilibrium solubility (MES) to describe the anomalous solubility behavior of carbonated apatite (CAP) in the presence of solution strontium. A CAP sample (4.8 wt% CO(3), synthesized at 70 degrees C) was prepared by precipitation. Baseline MES distributions were determined in a series of 0.1 M acetate buffers containing only calcium and phosphate (no strontium) over a broad range of solution conditions. In order to assess the influence of strontium, MES profiles were then determined in a similar fashion with 20, 30, 40, 50, 60, 70, and 80% of the solution calcium being replaced on an equal molar basis by solution strontium. From the compositions of the equilibrating buffer solutions, ion activity products (IAPs) of the form Ca(10-n)Sr(n)(PO(4))(6)(OH)(2) (n = 0-10) were calculated in an attempt to determine the correct function governing the dissolution of the CAP preparation. The results demonstrate the following important findings: (a) at high solution strontium/calcium ratios (i.e., when 60% or more of the solution calcium was replaced by strontium), the MES profiles in all the experiments were found to be essentially superimposable when the solution IAPs were calculated using the stoichiometry of Ca(6)Sr(4)(PO(4))(6)(OH)(2), and (b), at low solution strontium/calcium ratios (i.e., when 40% or less of the solution calcium was replaced by strontium), the stoichiometry yielding MES data superpositioning was found to be that of hydroxyapatite. When other stoichiometries were assumed, good superpositioning of the data was not possible.

DETERMINATION OF STRONTIUM IONS IN WATERS WITH A HIGH CONTENT OF SODIUM IONS

Directory of Open Access Journals (Sweden)

Tatiana Mitina

2015-06-01

Full Text Available This paper reports on the influence of sodium ions on experimental determination of strontium ions concentration in waters with a high content of sodium ions by using emission flame photometry and atomic absorption spectroscopy. For the method of emission flame photometry it was shown that at a wavelength of 460.7 nm (spectral emission line of strontium the emission is linearly dependent on the concentration of sodium ions. The greatest impact of high concentrations of sodium ions on the result of determination the strontium ions concentration has been registered at low levels of strontium. The influence of nitric acid on the results is also discussed. In the case of using atomic absorption spectroscopy method no influence of sodium ions and nitric acid on the results of determination the strontium ions concentration was revealed. The metrological characteristics of both methods are evaluated.

Effect of selected foodstuffs on strontium 89 metabolism in rats

International Nuclear Information System (INIS)

Keslev, D.; Jotov, M.

1975-01-01

The influence of a variety of food products used in human nutrition on strontium-89 cumulation in rat organism is studied. To this end the animals were fed for a week with meat, beans, maize, white and brown bread, cabbage, milk or potatoes prepared so as to be edible by man. Then for additional 15 days the animals were fed the same diet + a daily oral dose of 2 μCi strontium-89. On the 16th day radionuclide activity in the thigh bone was measured. Beans was the food product exerting optimal limiting effect on strontium deposition (reduction factor (RF) 17), milk and ranking next (RF 13, resp. 6.5). All other products showed approximately equal efforts (RF 1.4 - 1.8). The different calcium content of each of these food products is responsible for their different effectiveness. Together with the discrimination which the living organism displays in the presence of calcium, other constituents of the food products which form complexes with strontium and prevent its deposition in the bones are equally essential. (Ch.K.)

[Effects of strontium in drinking water on the growth of school-age children].

Science.gov (United States)

Tao, Y; Cao, S; Xu, F; Li, J

1999-09-30

An epidemiological study on the effect of strontium in drinking water on body shape development, bone age, prevalence of caries and dental fluorosis was carried out. The results show: there is a certain promotion on the development of bone age of school-age children, especially of girls, and there is no obvious impact on body shape developing when the concentration of strontium in drinking water is only 10 mg/L. The correlation between strontium in drinking water and the prevalence of caries in children could not get a conclusive evidence in this paper. A further epidemiological investigation is necessary if the role of strontium against caries should be proved.

The strontium isotopic composition of seawater, and seawater-oceanic crust interaction

International Nuclear Information System (INIS)

Spooner, E.T.C.

1976-01-01

The 87 Sr/ 86 Sr ratio of seawater strontium (0.7091) is less than the 87 Sr/ 86 Sr ratio of dissolved strontium delivered to the oceans by continental run-off (approximately 0.716). Isotope exchange with strontium isotopically lighter oceanic crust during hydrothermal convection within spreading oceanic ridges can explain this observation. In quantitative terms, the current 87 Sr/ 86 Sr ratio of seawater (0.7091) may be maintained by balancing the continental run-off flux of strontium (0.59 x 10 12 g/yr) against a hydrothermal recirculation flux of 3.6 x 10 12 g/yr, during which the 87 Sr/ 86 Sr ratio of seawater drops by 0.0011. A concomitant mean increase in the 87 Sr/ 86 Sr ratio of the upper 4.5 km of oceanic crust of 0.0010 (0.7029-0.7039) should be produced. This required 87 Sr enrichment has been observed in hydrothermally metamorphosed ophiolitic rocks from the Troodos Massif, Cyprus. The post-Upper Cretaceous increase in the strontium isotopic composition of seawater (approximately 0.7075-0.7091) covaries smoothly with inferred increase in land area. This suggests that during this period the main factor which has caused variability in the 87 Sr/ 86 Sr ratio of seawater strontium could have been variation in the magnitude of the continental run-off flux caused by variation in land area. Variations in land area may themselves have been partly a consequence of variations in global mean sea-floor spreading rate. (Auth.)

Sr-89 therapy: Strontium kinetics in disseminated carcinoma of the prostate

International Nuclear Information System (INIS)

Blake, G.M.; Zivanovic, M.A.; McEwan, A.J.; Ackery, D.M.

1986-01-01

Strontium kinetics were investigated in a group of 14 patients receiving 89 Sr palliation for metastatic bone disease secondary to prostatic carcinoma. Using 85 Sr as a tracer, total body strontium retention R(t) was monitored for a 3 month period following 89 Sr administration, and at 90 days was found to vary from 11% to 88% and to correlate closely with the fraction of the skeleton showing scintigraphic evidence of osteoblastic metastatic involvement. Strontium renal plasma clearance varied from 1.6l/ day to 11.6l/day, and in nine patients was significantly reduced compared with values found in healthy adult men, probably due to increased renal tubular reabsorption associated with the disturbance of calcium homoeostasis. Renal clearance rate was the principal factor determining R(t) for t 30 (t/30) -b , with R 30 and b showing the close correlation expected from the effect of R(t) on strontium recycling. The correction of the data for this effect to determine the true skeletal release rate is described. Measurement of localized strontium turnover in individual metastatic deposits from whole body profiles and scintigraphic images gave retention curves that typically rose to a plateau by 10 days after therapy, and then decreased very slowly. In contrast, retention curves for adjacent normal trabecular bone showed more rapid turnover, peaking at 1 day and subsequently decreasing following a t -0.2 power law function. The changes in strontium kinetics found in metastatic bone disease are favourable to the objectives of 89 Sr therapy. (orig.)

Strontium zirconate as silicon and aluminum scavenger in yttria stabilized zirconia

DEFF Research Database (Denmark)

Andersen, Thomas; Hansen, Karin Vels; Chorkendorff, Ib

2011-01-01

Here we report on strontium zirconate as a getter for silicon dioxide and aluminum oxide in yttria stabilized zirconia (YSZ) single crystals for cleaning purposes. YSZ single crystals were covered with strontium zirconate powder and heat treated at 1450°C in water vapor. After treatment the YSZ...... by transmission electron microscopy (TEM) the interface region between bump and YSZ single crystal bulk was examined. EDS showed a homogeneous distribution of silicon and aluminum through the cross section of a bump. The results suggest strontium zirconate as a good getter for silicon and aluminum from bulk...

Influence of La content on magnetic properties of Cu doped M-type strontium hexaferrite: Structural, magnetic, and Mossbauer spectroscopy study

Science.gov (United States)

Ghimire, M.; Yoon, S.; Wang, L.; Neupane, D.; Alam, J.; Mishra, S. R.

2018-05-01

The present study investigates the influence of Cu2+ and La3+-Cu2+ doping on the magnetic properties of Sr1-xLaxFe12-xCuxO19 (x = 0.0-0.5) hexaferrite (SrM) compounds. The samples were prepared via facile autocombustion technique followed by sintering. X-ray powder diffraction patterns show the formation of the pure phase of M-type hexaferrite for all x. Invariance in lattice parameters was observed with only Cu2+ substitution while lattice contraction along c-axis was observed with co-doping La3+-Cu2+ in SrM. The magnetic property of these compounds is explained based on Cu2+ occupancy in the absence and presence of La3+ in SrM magnetoplumbite structure. The Cu2+ doped SrFe12-xCuxO19 sample showed a monotonic decrease in Ms value while La3+-Cu2+ showed a noticeable increase in Ms value with x. Furthermore, while coercivity of Cu2+ doped SrM reduced with x, the coercivity of La3+-Cu2+ doped SrM showed a marked 12% increase in coercivity at x = 0.1 (Hc = 4391 Oe) from that of x = 0.0 (3918 Oe). Interestingly, Cu2+ doped SrM displayed invariance in Tc ∼ 458.6 °C with x, while La3+-Cu2+ doping reduced Tc by 5% from its x = 0 (Tc = 451.9 °C) to 429.6 °C. The room temperature Mossbauer spectral analysis confirmed a Cu2+ preference for the 12k site and its occupancy is observed to be influenced by the presence of La3+ ion at the Sr2+ site.

Formation of barium strontium titanate powder by solid state reaction using different calcination temperatures

International Nuclear Information System (INIS)

Teoh Wah Tzu; Ahmad Fauzi Mohd Noor; Zainal Arifin Ahmad

2002-01-01

The unique electrical properties of large permittivity in Barium Strontium Titanate have been widely used to make capacitors; it can be produced by solid state reaction. In this study, the mixture of Barium Carbonate, Strontium Carbonate and Titanium Dioxide was calcined at 500 degree C, 1000 degree C, 1100 degree C , 1150 degree C, 1200 degree C, 1250 degree C and 1300 degree C. The results of the phases change in each stage were investigated via X ay Diffraction. The results show that the formation of Barium Strontium Titanate started at 1100 degree C with the presence of other phases. The mixture is fully reacted to form Barium Strontium Titanate at 1150 degree C. Only Barium Strontium Titanate was formed as the calcination temperature was set higher. (Author)

Literature survey of strontium-89/90 analysis

International Nuclear Information System (INIS)

Kwakman, P.J.M.

1994-08-01

At the RIVM Laboratory of Radiation Research (LSO), the determination of strontium-89/90 in grass and milk samples using fuming nitric acid is a bottle neck in the routine monitoring programme, mainly due to the use of hazardous chemicals. In recent scientific articles, a number of alternatives have been described. This report gives an overview of the latest developments in this field and compares the pros and cons of these methods. The most promising method appears to be the 'Sr-spec' method developed by EIChrom Industries. In this method, an ion-exchanger is used for sorption of cations from the sample solution and, subsequently, a crown ether on a polymer support is applied for the selective complexation of bivalent strontium ions in the presence of other interfering bivalent ions. An important advantage is that the hazardous fuming nitric acid can be omitted and that the total number of chemical separation steps can be largely reduced. The possibility of a routine application of the 'Sr-spec' method for the determination of strontium-89/90 in grass and milk at RIVM/LSO is proposed. 2 tabs., 1 appendix, 23 refs

Electrical properties of Ba doped LSGM for electrolyte material of solid oxide fuel cells

Science.gov (United States)

Raghvendra, Singh, Prabhakar; Singh, Rajesh Kumar

2013-02-01

We report our investigations on Lanthanum Strontium Magnesium Gallate, LSGM, La0.8Sr0.2Ga0.8Mg0.2O3-δ doped with Barium at Strontium site having composition La0.8(Sr0.1Ba0.1)Ga0.8Mg0.2O3-δ (LSBGM). The pure cubic phase along with some additional phase was confirmed by XRD pattern. Electrical properties of the Composition LSBGM [La0.8(Sr0.1Ba0.1)Ga0.8Mg0.2O3-δ] prepared by solid state route, was studied employing impedance spectroscopy in the temperature range 573 K-993 K and frequency range 20 Hz-1MHz. The total ionic conductivity of the composition was found to be 0.072 S.cm-1 at 953 K and the activation energy from Arrhenius plot was found to be 1.16 eV in the measured temperature range. This confirms oxygen ion conductivity in the system. SEM micrograph shows the uniform densed particle morphology with gains of average size 200 nm.

Effects of strontium stress on antioxidant characteristics of oilseed rape seedling

International Nuclear Information System (INIS)

Ao Jia; Tang Yunlai; Chen Mei; An Bing; Wang Dan; Tao Yang

2010-01-01

Seedlings of oilseed rape (Brassica napus L.) were treated with different concentration of Sr 2+ (0, 10, 20, 40 mmol/L SrCl 2 ) for 0, 7, 14, 21 days under quartz sand and Hoagland solution culture, and the antioxidant characteristics and Sr 2+ accumulation of seedling were investigated. Rape seedlings showed high accumulation capacity for strontium, especial the leaves. But the accumulation capacity declined with the increasing of Sr 2+ concentration. The activity of superoxide dismutase (SOD) and the content of malondialdehyde (MDA) increased with the increasing of Sr 2+ concentration and then declined with the extention of the stress time. The activity of catalase (CAT) and peroxidase (POD) declined with the increasing of the Sr 2+ accumulation capacity. This study showed that oilseed rape had a very high strontium-tolerant and strontium-uptake capacity, and leaf was the organ that accumulates most of strontium. The accumulation capacity and activity of CAT, POD exhibited a significantly-negative correlation. (authors)

Biosorption of strontium ions from aqueous solution using modified eggshell materials

Energy Technology Data Exchange (ETDEWEB)

Metwally, Sayed S.; Rizk, Hoda E.; Gasser, Mona S. [Atomic Energy Authority, Cairo (Egypt). Hot Laboratories Center

2017-07-01

Green composites emphasize renewable starting materials for better economy using biomass materials. Therefore, low-cost composite biosorbent was prepared by modification of eggshell material using heteropoly acid for removal of strontium ions from aqueous solution. The resulted composite was characterized and evaluated for the sorption process using the batch technique. Low concentration of strontium ions was used to evaluate the sorption sensitivity of the prepared composite. The obtained experimental results illustrated that the modification process of eggshell material enhanced the percent uptake from 49.9 to 95.7%. From kinetic studies, the sorption of strontium ions follows the pseudo-second-order kinetic model. The isotherm studies indicated that Langmuir is more applicable than Freundlich isotherm. Moreover, Dubinin-Radushkevich isotherm was studied. Thermodynamic studies revealed that the sorption process is spontaneous and has endothermic nature. Strontium ions can be desorbed from the modified eggshell using HNO{sub 3}, desorption percent was found to be 96.4%; the results revealed the reusability of the modified eggshell for further sorption.

Study of the kinetics of strontium elimination in the rat; Etude de la cinetique de l'elimination du strontium chez le rat

Energy Technology Data Exchange (ETDEWEB)

Guilloux, M J; Michon, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1958-07-01

A kinetic study of strontium elimination was made on rats after a single oral administration of 3 to 5 {mu}curies of carrier free Sr{sup 90}. The curve showing the body burden in function of time may be considered as the sum of three exponential terms with half-lives of 14 hours, 72 days, 153 days. The term with a half-live of 153 days represents the metabolism of strontium in the bone; it is predominant since the 17. day and its extrapolation to time zero shows that things seem to proceed as if 18 per cent of the administered amount were deposited in the skeleton. (author) [French] La cinetique de l'elimination du strontium chez le rat a ete etudiee apres une administration orale unique de 3 a 5 {mu}curies de {sup 90}Sr repute sans entraineur. La courbe representant la quantite presente dans l'organisme en fonction du temps peut etre assimilee a la somme de trois termes exponentiels de periode 14 heures, 72 jours, 153 jours. Le terme de periode 153 jours represente le metabolisme osseux du strontium, il est preponderant des le 17. jour et son extrapolation au temps zero nous montre qu'en definitive, tout se passe comme si 18 pour cent de la quantite administree etaient deposes dans le squelette. (auteur)

Study of retention properties of fluoro-apatite carbonate relative to Ni(II), Am(III) and Th(IV)

International Nuclear Information System (INIS)

Perrone, Jane

1999-01-01

Apatite minerals and particularly the carbonated species (francolites), are characterized by their chemical and geological stability and also by their capacity to retain durably a large number of elements. Therefore, they should be able to improve the retention properties of the engineered barriers of a deep geological nuclear waste repository. But there is a wide variety of francolites, so we focused our study on a synthetic carbonate fluoro-apatite of formula: Ca 10 (PO 4 ) 5 (CO 3 )(F,OH) 3 and on a natural apatite. We first studied their solubility which is an important criterion for the choice of the materials. A particular attention was also paid to the determination of their surface characteristics and to the study of the radionuclide/solution interactions. Sorption experiments have been performed for the three radionuclides and the influence of various parameters has been investigated. The modelling of the sorption isotherms with surface complexation models leads us to estimate the values of the constants associated to the equilibria under consideration. We have also demonstrated that the phosphate ions of the solution participate to the immobilization of americium as the AmPO 4 ,xH 2 O compound. Both apatites show high retention levels for the actinides: the sorption is quite total over all the pH range studied and the Kd values are close to 10 4 m 3 kg -1 . Consequently, the use of apatites could be considered as a specific solution for the immobilisation of heavy elements, specially actinides. Moreover, the results indicate that high amounts of carbonates and impurities do not alter the retention properties of francolites. This bears out the feasibility of the use of natural apatites as additives for the engineered barrier materials. (author)

Synthesis of Nb-doped SrTiO₃ by a modified glycine-nitrate process

DEFF Research Database (Denmark)

Blennow Tullmar, Peter; Kammer Hansen, Kent; Wallenberg, L.R.

2007-01-01

The objective of the present investigation was to develop a technique to synthesize submicronic particles of Nb-doped strontium titanate with a homogeneous composition. This was achieved by a modified glycine-nitrate process, using Ti-lactate, Nb-oxalate, and Sr(NO3)(2) as starting materials....... A combination of both citric acid and glycine was needed in order to integrate the useful features of both complexation and combustion natures of citric acid and glycine, respectively. The amount of citric acid, glycine, and nitrates in the starting solution, as well as the source for extra nitrates...

Placental transfer of calcium and strontium and of their radionuclides

International Nuclear Information System (INIS)

Griessl, I.; Stieve, F.E.

1987-11-01

The first part of the report deals with the occurrence and the chemistry of strontium and its radioisotopes, and the second part discusses the calcium and the strontium metabolism in man. General information on the biology and physiology of the human skeleton is given in part 3, whereas part 4 again discusses the calcium and strontium metabolism in man, however with particular emphasis on the conditions during pregnancy and lactation. Part 5 presents an evaluation of the literature in this subject field, concentrating on results obtained with experimental animals such as cows, swine, dogs, guinea pigs, rats, and mice, and discusses the applicability of these findings to the conditions in man. An annex presents data on the yttrium metabolism in man and animal. (MG) [de

Thermoluminescence of strontium tetraborate

International Nuclear Information System (INIS)

Santiago, M.; Caselli, E.; Lester, M.

1999-01-01

The thermoluminescent properties of crystalline strontium tetraborate are reported. Without activators it has an efficiency comparable to that of TLD-700 powder. Its fading after 40 days amount to less than 2%. The isometric plot shows that most of the emitted light is concentrated at wavelengths ranging from 350 to 450 nm, which accounts partially for the high efficiency. (author)

The concentration of active and inactive strontium in some Danube river samples

International Nuclear Information System (INIS)

Koshutich, K.; Lulich, S.

1985-01-01

The following fish species were investigated: Barbus barbus, Acipencer ruthenus, Abramis brama, Stizostedion lucioperca, Silurus glanis, Cyprinus caprio. The samples were collected during 1981. The inactive strontium in the water residue (after evaporation), sediment and fishes ewrw determined by nondestructive neutron activation analysis by using gamma couting system consisted of a 40 cm 3 Ge(Li) semiconductor rystal attached to a 4096-channel pulsehight analyser. The standard solution contained 5x10 -5 g of strontium per 100 lambda. Radioactive strontium was measured after several separation procedures. 90 SrCO 3 in equilibrium with its daughter 90 Y was detected in the β-low-level counting anticoincident system with gas-flow detector. The results confirmed the literature data that the sediment concentrations of the total strontium and the active 90 Sr are several times greater than those in water

Bio sorption of strontium from aqueous solution by the new strain of bacillus sp. strain GT-83

International Nuclear Information System (INIS)

Tajer Mohammad Ghazvini, P.; Ghorbanzadeh Mashkani, S.; Mazaheri, M.

2009-01-01

An attempt was made to isolate bacterial strains capable of removing strontium biologically. In this study ten different water samples collected from Neydasht spring in the north of Iran and then the bacterial species were isolated from the water samples. The initial screening of a total of 50 bacterial isolates resulted in selection of one strain.The isolated strain showed a maximum adsorption capacity with 55 milligrams strontium/g dry wt. It was tentatively identified as Bacillus sp. According to the morphological and biochemical properties, and called strain GT-83. Our studies indicated that Bacillus sp. GT-83 is able to grow aerobically in the presence of 50 mM SrCl 2 , but its growth was inhibited at high levels of strontium concentrations. The bio sorption capacity of Bacillus sp. GT-83 depends strongly on the p H solution. Hence the maximum strontium sorption capacity of Bacillus sp. GT-83 was obtained at pah 10, independent of absence or presence of MgCl 2 of different concentrations. Strontium-salt bio sorption studies were also performed at this p H values. The equilibrium bio sorption of strontium was elevated by increasing the strontium concentration, up to 250 milligrams/l for Bacillus sp. GT-83. The maximum bio sorption of strontium was obtained at temperatures in the range of 30-35 d eg C . The Bacillus sp. GT-83 bio sorbed 97 milligrams strontium/g dry wt at 100 milligrams/l initial strontium concentration without MgCl 2 . When MgCl 2 concentration increased to 15%(w/v), these values dropped to 23.6 milligrams strontium/g dry wt at the same conditions. Uptake of strontium within 5 min of incubation was relatively rapid and the absorption continued slowly thereafter

Thermodynamic study on the adsorption of strontium on polyantimonic acid exchanger

International Nuclear Information System (INIS)

Li Mingyu; Chen Jing; Wang Jianchen; Zhao Jing

2007-01-01

The adsorption of strontium on the polyantimonic acid adsorbent was studied. The equilibrium data for the adsorption of strontium on polyantimonic acid exchanger from aqueous solutions were obtained and correlated with Langmuir-type and Freundlich-type isotherm equation within the temperature range of 293-323 K and the experimental concentration range. Freundlich adsorption isotherms and the isosteric enthalpy indicate that the adsorption of strontium on polyantimonic acid is an endothermic process from aqueous solutions. The enthalpy, free energy, and entropy of adsorption were calculated. The results indicate that the adsorption process is a complex interaction of physical and chemical processes. The adsorption behaviors were reasonably explained. (authors)

Udvikling af materialer til brintpermeable membraner

DEFF Research Database (Denmark)

Bentzer, Henrik Karnøe

doped samarium titanate, lanthanum magnesium titanate and strontium cerate doped with yttrium and nickel. Concentration cell measurements were used to estimate transport numbers for protons and oxide ions in yttrium doped strontium cerate and calcium doped samarium titanate. Furthermore, the voltage......Due to global warming as well as other factors, it is necessary to find alternatives to the current consumption of fossil fuels. Oxide materials with high protonic conductivity can potentially find application within many different technological fields in a society that is based on renewable energy...

Study of sorption processes of strontium on the synthetic hydroxyapatite

International Nuclear Information System (INIS)

Rosskopfova, O.; Galambos, M.; Rajec, P.

2011-01-01

The sorption of strontium on synthetic hydroxyapatite was investigated using batch method and radiotracer technique. The hydroxyapatite samples were prepared by a wet precipitation process followed by calcination of calcium phosphate that precipitated from aqueous solution. Also, commercial hydroxyapatites were used. The sorption of strontium on hydroxyapatite depended on the method of preparation and it was pH independent ranging from 4 to 9 as a result of buffering properties of hydroxyapatite. The distribution coefficient K d was significantly decreased with increasing concentration of Sr 2+ and Ca 2+ ions in solution with concentration above 1 x 10 -3 mol dm -3 . The percentage strontium sorption for commercial and by wet method prepared hydroxyapatite was in the range of 83-96%, while calcined hydroxyapatite was ranging from 10 to 30%. The experimental data for sorption of strontium have been interpreted in the term of Langmuir isotherm. The sorption of Sr 2+ ions was performed by ion-exchange with Ca 2+ cations on the crystal surface of hydroxyapatite. Although calcined hydroxyapatite is successfully used as biomaterial for hard tissues repair, it is not used for the treatment of liquid wastes. (author)

Strontium titanate thin film deposition - structural and electronical characterization

Energy Technology Data Exchange (ETDEWEB)

Hanzig, Florian; Hanzig, Juliane; Stoecker, Hartmut; Mehner, Erik; Abendroth, Barbara; Meyer, Dirk C. [TU Bergakademie Freiberg, Institut fuer Experimentelle Physik (Germany); Franke, Michael [TU Bergakademie Freiberg, Institut fuer Elektronik- und Sensormaterialien (Germany)

2012-07-01

Strontium titanate is on the one hand a widely-used model oxide for solids which crystallize in perovskite type of structure. On the other hand, with its large band-gap energy and its mixed ionic and electronic conductivity, SrTiO{sub 3} is a promising isolating material in metal-insulator-metal (MIM) structures for resistive switching memory cells. Here, we used physical vapour deposition methods (e. g. electron-beam and sputtering) to produce strontium titanate layers. Sample thicknesses were probed with X-ray reflectometry (XRR) and spectroscopic ellipsometry (SE). Additionally, layer densities and dielectric functions were quantified with XRR and SE, respectively. Using infrared spectroscopy free electron concentrations were obtained. Phase and element composition analysis was carried out with grazing incidence X-ray diffraction and X-ray photoelectron spectroscopy. Subsequent temperature treatment of samples lead to crystallization of the initially amorphous strontium titanate.

Strontium borate glass: potential biomaterial for bone regeneration.

Science.gov (United States)

Pan, H B; Zhao, X L; Zhang, X; Zhang, K B; Li, L C; Li, Z Y; Lam, W M; Lu, W W; Wang, D P; Huang, W H; Lin, K L; Chang, J

2010-07-06

Boron plays important roles in many life processes including embryogenesis, bone growth and maintenance, immune function and psychomotor skills. Thus, the delivery of boron by the degradation of borate glass is of special interest in biomedical applications. However, the cytotoxicity of borate glass which arises with the rapid release of boron has to be carefully considered. In this study, it was found that the incorporation of strontium into borate glass can not only moderate the rapid release of boron, but also induce the adhesion of osteoblast-like cells, SaOS-2, thus significantly increasing the cyto-compatibility of borate glass. The formation of multilayers of apatite with porous structure indicates that complete degradation is optimistic, and the spread of SaOS-2 covered by apatite to form a sandwich structure may induce bone-like tissue formation at earlier stages. Therefore, such novel strontium-incorporated borosilicate may act as a new generation of biomaterial for bone regeneration, which not only renders boron as a nutritious element for bone health, but also delivers strontium to stimulate formation of new bones.

A comparison of the palliative effects of strontium-89 and external beam radiotherapy in metastatic prostate cancer

International Nuclear Information System (INIS)

Quilty, P.M.; Kirk, D.; Bolger, J.J.; Dearnaley, D.P.; Mason, M.D.; Lewington, V.J.; Reed, N.S.E.; Russell, J.M.; Yardley, J.

1994-01-01

From 1988 to 1991, 284 patients with prostatic cancer and painful bone metastases were treated with either radiotherapy or strontium-89 (200 MBq). Patients were first stratified according to suitability for local or hemibody radiotherapy, then randomly allocated that form of treatment or strontium-89 (i.v. injection). After 4,8 and 12 weeks pain sites were mapped, toxicity monitored, and all additional palliative treatments recorded. There was no significant difference in median survival (after >80% had died); 33 weeks following strontium 8 9 and 28 weeks following radiotherapy (p=0.1). All treatments provided effective pain relief; improvement was sustained to 3 months in 63.6% after hemibody radiotherapy compared with 66.1% after strontium-89, and in 61% after local radiotherapy compared with 65.9% in the comparable strontium 8 9 group. Fewer patients reported new pain sites after strontium-89 than after local or hemibody radiotherapy (p < 0.05). Radiotherapy to a new site was required by 12 patients in the local radiotherapy group compared with 2 after strontium-89 (p < 0.01), although there was no significant difference between hemibody radiotherapy (6 patients) and strontium-89 (9 patients) in this respect. Platelets and leukocytes fell by an average 30-40% after strontium-89 but sequelae were uncommon, and other symptoms rare

Strontium D-Glutamate Hexahydrate and Strontium Di(hydrogen L-glutamate) Pentahydrate

DEFF Research Database (Denmark)

Christgau, Stephan; Odderhede, Jette; Stahl, Kenny

2005-01-01

Sr(C5H7NO4)] center dot 6H(2)O, ( I), and [Sr(C5H8NO4)(2)] center dot 5H(2)O, (II), both crystallize with similar strontium - glutamate - water layers. In ( I), the neutral layers are connected through hydrogen bonds by water molecules, while in ( II), the positively charged layers are connected...... through hydrogen bonds and electrostatic interactions by interleaving layers of hydrogen glutamate anions and water molecules....

Isolation of radioactive strontium from natural samples. Separation of strontium from alkaline and alkaline earth elements by means of mixed solvent anion exchange

International Nuclear Information System (INIS)

Grahek, Z.; Kosutic, K.; Lulic, S.; Kvastek, K.; Eskinja, I.

1999-01-01

This paper presents the results of studies which led to the procedures for the chromatographic separation of radioactive strontium from alkaline, earth-alkaline and other elements in natural samples, on columns filled with strong base anion exchangers using alcoholic solutions of nitric acid as eluents. It has been shown that potassium, caesium, calcium, barium, yttrium and strontium can be adsorbed on strong base anion exchangers of the Dowex and Amberlite type, which contain the quaternary ammonium group with nitrate as counter-ion, from solutions of nitric acid in alcohol. Adsorption strength increases in the order methanol 3 in methanol, while they are adsorbed from ethanol and propanol. The adsorption strength is influenced by the polarity of alcohol, by the concentration of nitrate and by pH. The strength with which strontium adsorbs on the exchangers increases in the interval from 0 to 0.25M NH 4 NO 3 in methanol, after which it starts to decrease. Strontium adsorbs to the exchangers from the alcoholic solution of ammonium nitrate twice as strongly as from the alcoholic solution of nitric acid, while a fraction of water in pure alcohol exceeding 10% prevents adsorption. In the mixture of alcohol and nitric acid, the adsorption strength for calcium and strontium increases with the increase of the volume fraction of alcohol with a lower dielectric constant. The rate and strength of adsorption of ions on the exchanger also increase in the series 0.25M HNO 3 in methanol 3 in ethanol 3 in 1-propanol for each individual ion, as well as in the Ca 3 in methanol, 0.25M HNO 3 in ethanol and 0.25M HNO 3 in propanol. Separation is also possible from alcohol mixtures. Strontium separation is most difficult from calcium, while the efficiency of separation increases with a decrease of the polarity of the used alcohol or alcohol mixture. The first group elements of the periodic table are not separated from each other in this way, while the elements of the second group are

Tunable dielectric properties of Barium Magnesium Niobate (BMN) doped Barium Strontium Titanate (BST) thin films by magnetron sputtering

Science.gov (United States)

Alema, Fikadu; Reinholz, Aaron; Pokhodnya, Konstantin

2013-03-01

We report on the tunable dielectric properties of Mg and Nb co-doped Ba0.45Sr0.55TiO3 (BST) thin film prepared by the magnetron sputtering using BST target (pure and doped with BaMg0.33Nb0.67O3 (BMN)) on Pt/TiO2/SiO2/Al2O3 4'' wafers at 700 °C under oxygen atmosphere. The electrical measurements are conducted on 2432 metal-ferroelectric-metal capacitors using Pt as the top and bottom electrode. The crystalline structure, microstructure, and surface morphology of the films are analyzed and correlated to the films dielectric properties. The BMN doped and undoped BST films have shown tunabilities of 48% and 52%; and leakage current densities of 2.2x10-6 A/cm2 and 3.7x10-5 A/cm2, respectively at 0.5 MV/cm bias field. The results indicate that the BMN doped film exhibits a lower leakage current with no significant decrease in tunability. Due to similar electronegativity and ionic radii, it was suggested that both Mg2+ (accepter-type) and Nb5+ (donor-type) dopants substitutTi4+ ion in BST. The improvement in the film dielectric losses and leakage current with insignificant loss of tunability is attributed to the adversary effects of Mg2+ and Nb5+ in BST.

Sorption of strontium on uranyl peroxide: implications for a high-level nuclear waste repository.

Science.gov (United States)

Sureda, Rosa; Martínez-Lladó, Xavier; Rovira, Miquel; de Pablo, Joan; Casas, Ignasi; Giménez, Javier

2010-09-15

Strontium-90 is considered the most important radioactive isotope in the environment and one of the most frequently occurring radionuclides in groundwaters at nuclear facilities. The uranyl peroxide studtite (UO2O2 . 4H2O) has been observed to be formed in spent nuclear fuel leaching experiments and seems to have a relatively high sorption capacity for some radionuclides. In this work, the sorption of strontium onto studtite is studied as a function of time, strontium concentration in solution and pH. The main results obtained are (a) sorption is relatively fast although slower than for cesium; (b) strontium seems to be sorbed via a monolayer coverage of the studtite surface, (c) sorption has a strong dependence on ionic strength, is negligible at acidic pH, and increases at neutral to alkaline pH (almost 100% of the strontium in solution is sorbed above pH 10). These results point to uranium secondary solid phase formation on the spent nuclear fuel as an important mechanism for strontium retention in a high-level nuclear waste repository (HLNW). Copyright 2010 Elsevier B.V. All rights reserved.

Separation of americium (III) and strontium (II) using TEHDGA and 18-crown-6

Energy Technology Data Exchange (ETDEWEB)

Sinharoy, Prithwish; Khan, Pasupati Nath; Nair, Deepika; Jagasia, Poonam; Dhami, P.S.; Kaushik, C.P.; Banerjee, Kalyan [Bhabha Atomic Research Centre, Mumbai (India). Nuclear Recycle Group; Anitha, M. [Bhabha Atomic Research Centre, Mumbai (India). Rare Earth Development Section; Sharma, J.N. [Bhabha Atomic Research Centre, Mumbai (India). Process Development Div.

2017-06-01

This work describes extraction of Am(III) and Sr(II) together with tetra(2-ethylhexyl) diglycolamide (TEHDGA) and selective back-extraction of strontium with a strontium complexant, 18-crown-6, leading to their separation from each other. 0.3 M TEHDGA+5% isodecyl alcohol/n-dodecane was used to extract Am(III) and Sr(II) from 4 M nitric acid into organic phase with very high D (D{sub Am}=1000, D{sub Sr}=22) and 0.1 M 18-crown-6 dissolved in 4 M nitric acid is used for selective stripping of Sr(II) from loaded extract phase. Am(III) left in the extract phase was then stripped with 0.01 M nitric acid. Stripping of Sr(II) was found to increase with increase in 18-crown-6 concentration, at 0.1 M 18-crown-6 dissolved in 4 M nitric acid, 83% of the loaded strontium (D{sub Sr}=0.20) was back-extracted in a single contact while loss of Am(III) was 0.8% (D{sub Am}=122.45). Stoichiometry limit of 1:1 was observed between strontium and 18-crown-6. Strontium was precipitated and separated from the complexant by Na{sub 2}SO{sub 4} or Na{sub 2}CO{sub 3}. This process was tested with simulated solution of high level waste and found suitable for quantitative recovery of strontium with high purity.

Development of novel strontium containing bioactive glass based calcium phosphate cement.

Science.gov (United States)

D'Onofrio, A; Kent, N W; Shahdad, S A; Hill, R G

2016-06-01

The aim of this study was to investigate the effect on properties of increasing strontium substitution for calcium in bioactive glasses used as precursors for novel calcium phosphate cements. Glasses were produced by progressively substituting strontium for calcium. Cements were prepared by mixing the glass powder with Ca(H2PO4)2 powder with a 2.5% solution of Na2HPO4. Setting times and compressive strength were measured after 1h, 1 day, 7 days and 28 days immersion in Tris buffer solution. X-ray diffraction (XRD), Fourier transform infrared spectroscopy and radiopacity were measured and crystal morphology was assessed using scanning electron microscopy. A correlation between the phases formed, morphology of the crystallites, setting time and compressive strength were analyzed. Setting time increased proportionally with strontium substitution in the glass up to 25%, whereas for higher substitutions it decreased. Compressive strength showed a maximum value of 12.5MPa and was strongly influenced by the interlocking of the crystals and their morphology. XRD showed that the presence of strontium influenced the crystal phases formed. Octacalcium phosphate (Ca8H2(PO4)6·5H2O, OCP) was the main phase present after 1h and 1 day whereas after 28 days OCP was completely transformed to strontium-containing hydroxyapatite (SrxCa(10-x)(PO4)6(OH)2, SrHA). Radiopacity increased proportionally to strontium substitution in the glass. A novel method to develop a bone substitute forming in vitro SrHA as a final product by using a bioactive glass as a precursor was shown. These novel injectable bioactive glass cements are promising materials for dental and orthopedic applications. Further in vivo characterizations are being conducted. Copyright © 2016 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Study of the separation of strontium from solutions which imitate natural waters of increased mineralization

International Nuclear Information System (INIS)

Golub, A.M.; Voitko, I.N.; Glushchenko, L.V.; Mitrofanova, O.G.; Zyryanova, N.P.

1976-01-01

It has been shown by experiments on synthetically prepared solutions that it is possible to separate strontium and calcium by carbonate precipitation from the larger part of the magnesium accompanying them in natural high mineral waters. In this way the residual content of strontium is reduced to a value of 40-50 mg/liter and, under conditions of removing CO 2 from the solution, to 5-10 mg/liter. The high ionic strength of the solution prevented a more complete precipitation of strontium. Magnesium may be isolated from the filtrate after precipitation of the calcium-strontium mixture. The possibility has been shown of isolating strontium from the mixture of carbonates by means of pyrolysis at 1100-1200 0 and the selective solution of SrO in hot water

Local structure and speciation of uranium in strontium orthosilicate: TRFS and EXAFS studies

International Nuclear Information System (INIS)

Gupta, Santosh K.; Thulasidas, S.K.; Natarajan, V.; Yadav, A.K.; Bhattacharya, D.

2015-01-01

TRFS is used to investigate the valence state and coordination behavior of uranium in strontium orthosilicate. From TRFS measurement it was observed that uranium exists as U(VI) in the form of UO 2 2+ in Sr 2 SiO 4 . Based on life time measurement and EXAFS studies it was inferred that uranyl is stabilized on both 9- and 10- coordinated strontium polyhedra. Majority of uranyl ion occupy relatively asymmetric site in strontium silicate most probably 9-coordinated Sr sites. (author)

Investigation of the elution by seawater of caesium and strontium from loaded clinoptilolite

International Nuclear Information System (INIS)

Harder, B.R.; Mitchell, I.H.; Smyth, M.J.

1985-07-01

Simple investigations of the elution of caesium and strontium from loaded clinoptilolite are described. The clinoptilolite was loaded to levels expected in the British Nuclear Fuels plc SIXEP plant and contacted with seawater at approx. 15 C. (The elution time was measured until about 99% of the caesium and strontium had been eluted.) It was found that 99% of the caesium was eluted in 35 hours but the strontium (with more variable results) took at least 400 hours for 99% elution. (author)

Separation of fission strontium from nuclear fuels by ammonium molybdatophosphate

International Nuclear Information System (INIS)

Hermann, A.

1984-01-01

The separation of fission strontium from solutions of prolonged cooled nuclear fuel has been performed using ammoniummolybdatophosphate (AMP) columns. The sorption mechanism of bivalent ions of AMP has been investigated by column and batch experiments. A pure ion exchange of Sr 2+ for two H + or NH 4 + ions has been established. Conditions for the sepasorption and elution of fission strontium and other fission products on AMP columns are described. (author)

Interactive effects of vitamin D3 and strontium on performance, nutrient retention and bone mineral composition in laying hens.

Science.gov (United States)

Browning, Linda C; Cowieson, Aaron J

2015-03-30

Strontium is currently prescribed for patients with osteoporosis to increase bone density and reduce bone fractures but its relevance in animal nutrition is obscure. In order to investigate the effect of supplemental strontium and vitamin D3 on performance, egg quality and skeletal integrity in poultry a total of 108 laying hens, 99 weeks of age, were fed three levels of strontium (0, 500, 1000 mg kg(-1) ) and two levels of vitamin D3 (2500, 5,000 iu kg(-1)) over a 12-week period. There was an improvement (P < 0.05) in egg production and feed conversion efficiency with strontium at 500 mg kg(-1) and a significant increase in egg weight in those hens fed additional vitamin D3 . Supplemental strontium increased phosphorus, sodium and strontium retention in birds fed 2500 iu D3 kg(-1) but reduced phosphorus, sodium and strontium retention in birds fed 5000 iu D3 kg(-1), resulting in an interaction (P < 0.01) between strontium and vitamin D3 . Addition of 5000 iu D3 kg(-1) increased egg weight (P < 0.05); predominantly by increased albumen content (P < 0.05), whereas strontium supplementation reduced egg weight (P < 0.001). Similarly, 5000 iu kg(-1) D3 increased apparent metabolizable energy (P < 0.05); in contrast, strontium supplementation reduced (P < 0.05) apparent metabolizable energy. The addition of 500 mg kg(-1) strontium significantly improved egg production and feed efficiency; however, further investigation needs to be undertaken to refine the optimum level of strontium required to maximize hen performance. The interrelationship between strontium and vitamin D3 requires further exploratory study. © 2014 Society of Chemical Industry.

Hydrologic inferences from strontium isotopes in pore water from the unsaturated zone at Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Marshall, B.D.; Futa, K.; Peterman, Z.E.

1997-01-01

Calcite is ubiquitous at Yucca Mountain, occurring in the soils and as fracture and cavity coatings within the volcanic tuff section. Strontium is a trace element in calcite, generally at the tens to hundreds of ppm level. Because calcite contains very little rubidium and the half-life of the 87 Rb parent is billions of years, the 87 Sr/ 86 Sr ratios of the calcite record the ratio in the water from which the calcite precipitated. Dissolution and reprecipitation does not alter these compositions so that, in the absence of other sources of strontium, one would expect the strontium ratios along a flow path to preserve variations inherited from strontium in the soil zone. Strontium isotope compositions of calcites from various settings in the Yucca Mountain region have contributed to the understanding of the unsaturated zone (UZ), especially in distinguishing unsaturated zone calcite from saturated zone calcite. Different populations of calcite have been compared, either to group them together or distinguish them from each other in terms of their strontium isotope compositions. Ground water and perched water have also been analyzed; this paper presents strontium isotope data obtained on pore water

Sintering and Electrical Characterization of La and Nb Co‐doped SrTiO3 Electrode Materials for Solid Oxide Cell Applications

DEFF Research Database (Denmark)

Sudireddy, Bhaskar Reddy; Agersted, Karsten

2014-01-01

Single‐phase lanthanum and niobium co‐doped strontium titanate (Sr1–3x/2LaxTi0.9Nb0.1O3; x = 0–0.02) ceramics were prepared. Dilatometry in reducing atmosphere showed an increase in the sintering rate and sintered density with an increase in La amount. Microscopy of fractured surfaces of sintered...... samples showed that the average grain size increased drastically in reducing conditions with increasing La content (and associated A‐site vacancies). By incorporating 2 mol.% La, the electronic conductivity significantly improved from 80 to 135 S cm−1 at 1,000 °C, and even larger improvements were...... observed at lower temperatures. These observations demonstrate the flexibility in tailoring the microstructure and electronic transport properties by doping small amounts of La into the Nb‐doped SrTiO3 and show that Sr1–3x/2LaxTi0.9Nb0.1O3 is a potential electrode material for solid oxide cells....

Application of dicyclohexyl-18-crown-6 to selective extraction of radioactive strontium from waters

International Nuclear Information System (INIS)

Yakshin, V.V.; Myasoedov, B.F.; Vilkova, O.M.; Tuzova, A.M.; Fedorova, A.T.; Rodionova, I.M.

1989-01-01

Influence of various factors on strontium extraction in the system nitric acid-dicyclohexyl-18-crown-6 was studied to develop the technique for determining 89 Sr and 90 Sr content in natural waters and aqueous salt solutions. Conditions for selective strontium extraction from complex salt systems containing Ba, Cs, Ru, Ce and other radionuclides were found. It is shown that coefficient of strontium distribution is sufficiently higher, as compared to coefficients of Cs, Ru, Ce distribution. Extraction performance under chosen conditions enables to elevate sufficiently the distribution coefficient of these substances. The scheme of radiochemical analysis is given. Strontium content in natural waters and salt solutions was determined with the use of described radiochemical method

Investigation of aluminium-rich alloy system of aluminium-strontium-silicium

International Nuclear Information System (INIS)

Ganiev, I.N.; Vakhobov, A.B.; Dzhuraev, T.D.; Alidzhanov, F.N.

1976-01-01

An area of the solid solution based on aluminium was studied, and the surface was plotted of the liquidus adjoining the apex of the aluminium corner of the strontium-aluminium-silicon system. The investigation was carried out by microstructure and differential thermal analyses and by the measurement of the microhardness of the component phases. A combined solubility of silicon and strontium in aluminium was studied along three radial sections at Sr-to-Si ratios of 1/2, 1/1 and 2/1. The relationships of ''composition vs. Microhardness'', obtained in these sections, made it possible to define the boundaries of the phase regions in the aluminium corner of the strontium-aluminium-silicon system at 500 deg C. The greatest solubility is that along the Al-SrAl 2 Si 2 section at a Sr/Si ratio of 1/2. A further increase in the content of strontium brings about a drop in the solubility of silicon in solid aluminium. The projection of the liquidus surface of the strontium-aluminium-silicon system, rich in aluminium, includes four surfaces of primary crystallization: α-Al, SrAl 4 , SrAl 2 Si 2 and Si. The system comprises a section of Al-SrAl 2 Si 2 representing a quasibinary system of an eutectic type. The eutectic reaction takes place at a temperature of 640 deg C. The quasibinary Al-SrAl 2 Si 2 section divides the aluminium corner of the Sr-Al-Si system into two independent systems Al-SrAl 4 -SrAl 2 Si 2 and Al-Si-SrAl 2 Si 2 of an eutectic type

Effects of mineralogy on sorption of strontium and cesium onto Calico Hills Tuff

International Nuclear Information System (INIS)

Meyer, R.E.; Arnold, W.D.; Case, F.I.; O'Kelley, G.D.; Land, J.F.

1990-04-01

The sorption properties of tuff formations at the proposed site for the high-level nuclear waste repository at Yucca Mountain, Nevada, have been extensively studied. Sorption and desorption measurements were made of strontium and cesium onto clinoptilolite and Calico Hills Tuff. The object was to see whether there was a correlation between sorption of strontium and cesium onto Calico Hills Tuff and the sorption of strontium and cesium onto clinoptilolite based on the content of clinoptilolite in the Calico Hills Tuff. 13 refs., 10 figs., 6 tabs

Study on the Key Technology of High Purity Strontium Titanate Powder Synthesized from Oxalic Acid Co-sediment Precipitation

Science.gov (United States)

Bi, Xiaoguo; Dong, Yingnan; Li, Yingjie; Niu, Wei; Tang, Jian; Ding, Shuang; Li, Meiyang

2017-09-01

Oxalate coprecipitation is applied in this paper, high purity titanium tetrachloride, and after the purification of strontium chloride, match with a certain concentration of solution, oxalate and strontium chloride and titanium tetrachloride in 1.005:1.000 make strontium titanium mixture ratio, slowly under 60°C to join in oxalic acid solution, aging around 4 h, get oxygen titanium strontium oxalate (SrTiO(C2O4)2 • 4H2 ) precipitation, after washing, drying and other process made oxygen titanium strontium oxalate powder.

Urinary strontium and the risk of breast cancer: A case-control study in Guangzhou, China

Energy Technology Data Exchange (ETDEWEB)

Chen, Li-Juan [The School of Public Health, Sun Yat-sen University, 74 Zhongshan 2nd Rd, Guangzhou 510080 (China); Tang, Lu-Ying [The School of Public Health, Sun Yat-sen University, 74 Zhongshan 2nd Rd, Guangzhou 510080 (China); The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou 510630 (China); He, Jian-Rong [The School of Public Health, Sun Yat-sen University, 74 Zhongshan 2nd Rd, Guangzhou 510080 (China); Guangzhou Women and Children' s Medical Center, Guangzhou 510623 (China); Su, Yi; Cen, Yu-Ling; Yu, Dan-Dan [The School of Public Health, Sun Yat-sen University, 74 Zhongshan 2nd Rd, Guangzhou 510080 (China); Wu, Bang-Hua [The Guangdong Prevention and Treatment Center for Occupational Diseases, Guangzhou 510300 (China); Lin, Ying [The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080 (China); Chen, Wei-Qing [The School of Public Health, Sun Yat-sen University, 74 Zhongshan 2nd Rd, Guangzhou 510080 (China); Song, Er-Wei, E-mail: songerwei02@yahoo.com.cn [The Second Affiliated Hospital, Sun Yat-sen University, 107 Yanjiang West, Guangzhou 510120 (China); Ren, Ze-Fang, E-mail: renzef@mail.sysu.edu.cn [The School of Public Health, Sun Yat-sen University, 74 Zhongshan 2nd Rd, Guangzhou 510080 (China)

2012-01-15

Strontium has been widely used in industries like electronic and pharmacy. It has a carcinogenic potential, however, and no study has been conducted to evaluate its effects on cancer risk. The aim of this study was to explore the possible association between strontium and breast cancer risk in a case-control study including 240 incident invasive breast cancer patients and 246 age-matched controls. We measured the urinary concentrations of strontium by inductively coupled plasma mass spectrometry, and conducted face-to-face interviews to obtain information on potential breast cancer risk factors. Multivariable analysis was used to estimate the association. Creatinine-adjusted levels [median (25th, 75th) {mu}g/g] of strontium were 155.59 (99.05, 230.70) in the breast cancer patients and 119.62 (81.97, 163.76) in the controls. Women in the highest tertile of strontium showed 124% increased risk of breast cancer, when compared with those in the lowest tertile after adjustment for the potential risk factors [OR (95% CI): 2.24 (1.42-3.81)]. This association was particularly strong for HER2 positive breast cancer [OR (95% CI): 10.92 (3.53-33.77)], and only occurred among premenopausal women. These results suggest a potential role of strontium in the development of breast cancer and urge further studies on the environmental contamination and the physiological and pathological mechanisms of strontium.

The role of Sr doping on structure and microstructural properties of LaFeO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Jain, Pranat, E-mail: pranatjain@gmail.com; Srivastava, Sanjay, E-mail: s.srivastava.msme@gmail.com [Department of Materials Science & Metallurgical Engineering, Maulana Azad National Institute of Technology, Bhopal-4620003 (India); Gupta, Nitish, E-mail: nitish.nidhi75@gmail.com [Department of App. Chemistry, Shri G.S. Institute of Technology and Science, 23 Park Road Indore 452003 (India)

2016-05-06

The doping of Strontium in LaFeO{sub 3} and its influence on the structural and microstructure properties were studied thoroughly. A few sets of Sr doping in La{sub (1-x)}Fe{sub x}O{sub 3}, where x=0.00, 0.02, and 0.06 were made through the solution combustion synthesis method using urea as fuel. X-ray diffraction was applied to get information about the structure and purity. The Rietveld refinement on X-ray diffraction peaks have been done, in order to calculate various structural parameters. The morphology of La{sub (1-x)}Sr{sub x}FeO{sub 3} nanoscale particles has been confirmed by field emission scanning electron microscopy (FESEM) technique. Differential scanning calorimetry (DSC) signals demonstrated the antiferromagnetic to paramagnetic transition (T{sub N}). The FTIR spectra was provided the information about various vibration modes in samples.

Distribution of strontium in DB18K6 and DTBDB18K6 systems

International Nuclear Information System (INIS)

Usarov, Z.O.; Khujaev, S.

2007-01-01

Distributions of strontium in DB18K6 and DTBDB18K6 crown-ethers in chloroform were investigated for extraction of strontium from water solutions of nitric acid. Nitrate solutions with various pH were considered. In both crown-ethers the most extraction of strontium was observed for the moderate pH values. Equilibrium of extraction process is reached for comparatively short time and is occurred to be 20 min (authors)

Strontium-90 and cesium-137 in sea sediments (from May 1984 to Sep 1984)

International Nuclear Information System (INIS)

1984-01-01

Strontium-90 and cesium-137 monitoring results are presented for sea sediment samples of 12 sampling points located all over Japan from Tomari, Hokkaido to Kinnakagusuku Bay, Okinawa. The samples were collected by considering of enough sea water depth, no significant sedimental movement and sediment characteristics, and by employing a conventional sampling device. Approximately 4 kg-wet sample was dried and was passed through a 20 cm mesh sieve. After adding of strontium and cesium carriers, strontium-90 and cesium-137 were leached with a hot hydrochloric acid solution. The leachate was treated by ion exchange and coprecipitation to concentrate and isolate strontium-90 or cesium-137. Radiation counting was carried out by employing a low background beta counter usually for 60 minutes for the samples of strontium carbonate or cesium chloroplatinate. Determined strontium-90 contents in sea sediment were distributed from 0 +- 2.7 pCi/kg-dry (Mutsu Bay, Aomori, Yamaguchi Bay, Yamaguchi) to 14 +- 3.2 pCi/kg-dry (Mutsu Bay), and those of cesium-137 were from 9 +- 3.5 pCi/kg-dry (Mutsu Bay) to 250 +- 9 pCi/kg-dry (Off-Niigata Port, Niigata). Local variation of the contents of these radionuclides was very large, and for seasonal variation, it was also found large for the both nuclides content in the Mutsu Bay samples of May, 1984 and August 1984, as for strontium-90, 0 +- 2.7 pCi/kg and 14 +- 3.2 pCi/kg, for cesium-137, 9 +- 3.5 pCi/kg and 200 +- 8 pCi/kg, respectively. (Takagi, S.)

Strontium ranelate improved tooth anchorage and reduced root resorption in orthodontic treatment of rats.

Science.gov (United States)

Kirschneck, Christian; Wolf, Michael; Reicheneder, Claudia; Wahlmann, Ulrich; Proff, Peter; Roemer, Piero

2014-12-05

The anchorage mechanisms currently used in orthodontic treatment have various disadvantages. The objective of this study was to determine the applicability of the osteoporosis medication strontium ranelate in pharmacologically induced orthodontic tooth anchorage. In 48 male Wistar rats, a constant orthodontic force of 0.25 N was reciprocally applied to the upper first molar and the incisors by means of a Sentalloy(®) closed coil spring for two to four weeks. 50% of the animals received strontium ranelate at a daily oral dosage of 900 mg per kilogramme of body weight. Bioavailability was determined by blood analyses. The extent of tooth movement was measured both optometrically and cephalometrically (CBCT). Relative alveolar gene expression of osteoclastic markers and OPG-RANKL was assessed by qRT-PCR and root resorption area and osteoclastic activity were determined in TRAP-stained histologic sections of the alveolar process. Compared to controls, the animals treated with strontium ranelate showed up to 40% less tooth movement after four weeks of orthodontic treatment. Gene expression and histologic analyses showed significantly less osteoclastic activity and a significantly smaller root resorption area. Blood analyses confirmed sufficient bioavailability of strontium ranelate. Because of its pharmacologic effects on bone metabolism, strontium ranelate significantly reduced tooth movement and root resorption in orthodontic treatment of rats. Strontium ranelate may be a viable agent for inducing tooth anchorage and reducing undesired root resorption in orthodontic treatment. Patients under medication of strontium ranelate have to expect prolonged orthodontic treatment times. Copyright © 2014 Elsevier B.V. All rights reserved.

Stable strontium isotopic ratios from archaeological organic remains from the Thorsberg peat bog

DEFF Research Database (Denmark)

Nosch, Marie-Louise Bech; von Carnap-Bornheim, Claus; Grupe, Gisela

2007-01-01

Pilot study analysing stable strontium isotopic ratios from Iron Age textile and leather finds from the Thorsberg peat bog.......Pilot study analysing stable strontium isotopic ratios from Iron Age textile and leather finds from the Thorsberg peat bog....

Strontium-90 and cesium-137 in soil (from May 1985 to Jul. 1985)

International Nuclear Information System (INIS)

1985-01-01

This report is aimed at listing measurements of strontium-90 and cesium-137 in soil made at eight places across Japan during the period from May to July in 1985. Collection and pretreatment methods are described for samples of rain and dry fallout, airborne dust, service water and freshwater, soil, sea water, sea sediments, total diet, rice, milk, vegetables, tea, as well as fish, shellfish and seaweeds. The methods for the preparation of these samples for analysis are also outlined. Sample solutions were neutralized with sodium hydroxide, and the precipitate of strontium and calcium carbonates was separated after sodium carbonate was added. The supernatant solution was retained for cesium-137 determination. After being precipitated as oxalates, strontium and calcium were separated by successive fuming nitric acid separations. For the determination of stable strontium, calcium and potassium, soil and sediment were treated with sodium hydroxide and hydrochloric acid for extraction while other samples were ashed and digested. Calcium, separated as oxalate, was determined by titration while stable strontium and potassium were determined by atomic absorption and flame emission spectroscopy, respectively. Couting for activity was carried out using low background beta counters normally for 60 min. (Nogami, K.)

Studies of cesium and strontium migration in unconsolidated Canadian geological materials

International Nuclear Information System (INIS)

Gillham, R.W.; Lindsay, L.E.; Reynolds, W.D.; Kewen, T.J.; Cherry, J.A.; Reddy, M.R.

1981-06-01

Distribution coefficients (Ksub(d)) were measured for cesium and strontium in 16 samples of Canadian unconsolidated geological materials. The samples were collected to cover a wide range of grain size, clay-mineral composition, cation exchange capacity and carbonate mineral content. Distribution coefficients ranged between 10 2 and 2.0 x 10 4 ml/g for cesium and between 2.5 and 10 2 ml/g for strontium, indicating that most unconsolidated geological materials have a substantial ability to retard the migration of cesium, while strontium could generally be expected to be somewhat more mobile. The measured K values were not significantly correlated with the measured soil properties, but appeared to be significantly affected by the background concentration of stable isotopes of the respective radionuclides

Innovation in metrology: fast automated radiochemical separation and measurement for strontium 89 and 90

Energy Technology Data Exchange (ETDEWEB)

Augeray, C.; Galliez, K.; Mouton, M.; Tarlette, L.; Loyen, J.; Fayolle, C.; Gleizes, M. [Institut de Radioprotection et de Surete Nucleaire - IRSN (France)

2014-07-01

Measuring radioactivity in the food and for radiological monitoring of the environment around Nuclear Facilities or mining sites requires the quantification of the radioactive isotopes present in the different compartments (liquids or solids), especially of the beta emitters. Strontium 89 and 90, both pure beta emitters are radioactive isotopes of interest. Because of their toxicity and the similarity of their chemical and physical behavior with calcium, these elements may be found through the food chain. After the Fukushima accident, the necessity of quantifying quickly radioactive isotopes such as strontium 89 and 90 appeared. The technique we are going to present concerns the determination of the activity concentration of strontium 89 and 90 in water, according to the {sup 89}Sr/{sup 90}Sr ratio. It consists of two stages: the chemical separation by ionic chromatography and the measurement of the activity concentration of strontium 89 and 90 by Cerenkov Effect. The automated separation has been developed and allows isolating the isotopes of strontium in particular the radioactive ones: strontium 89 and 90. The separation can be done within one hour. It was realized from the adaptation of existing analytical chemistry equipments with on-line couplings. The protocol of separation is based on the use of ions exchange columns of Ionic chromatography not as a separation and measurement technique of the cation but only as a separation technique. At the release time of the ion to be quantified, a fraction collector allows its recovery. The test portion is then analyzed with a liquid scintillation counter (LSC). The activity concentration is measured by Cerenkov Effect on a quenched sample. The quenching is realized by applying a thin colored film on the sample vial. This color quench is used to make strontium 90 counts disappear on the LS spectrum. This way, only yttrium 90 ingrowth and strontium 89 decay are measured (E{sup 90}Sr < E{sup 89}Sr < E{sup 90}Y

Review and evaluation of extractants for strontium removal using magnetically assisted chemical separation

International Nuclear Information System (INIS)

Bauer, C.B.; Rogers, R.D.

1995-11-01

A literature review on extractants for strontium removal was initially performed at Northern Illinois University to assess their potential in magnetically assisted chemical separation. A series of potential strontium extractants was systematically evaluated there using radioanalytical methods. Initial experiments were designed to test the uptake of strontium from nitric acid using several samples of magnetic extractant particles that were coated with various crown ether ligands. High partition coefficient (K d ) values for stimulant tank waste were obtained. Further studies demonstrated that the large partitioning was due to uncoated particles

Review and evaluation of extractants for strontium removal using magnetically assisted chemical separation

Energy Technology Data Exchange (ETDEWEB)

Bauer, C.B.; Rogers, R.D. [Northern Illinois Univ., De Kalb, IL (United States). Dept. of Chemistry; Nunez, L.; Ziemer, M.D.; Pleune, T.T.; Vandegrift, G.F. [Argonne National Lab., IL (United States)

1995-11-01

A literature review on extractants for strontium removal was initially performed at Northern Illinois University to assess their potential in magnetically assisted chemical separation. A series of potential strontium extractants was systematically evaluated there using radioanalytical methods. Initial experiments were designed to test the uptake of strontium from nitric acid using several samples of magnetic extractant particles that were coated with various crown ether ligands. High partition coefficient (K{sub d}) values for stimulant tank waste were obtained. Further studies demonstrated that the large partitioning was due to uncoated particles.

Spectrographic determination of strontium in yttrium-90 solutions

International Nuclear Information System (INIS)

Roca, M.; Capdevila, C.

1970-01-01

The copper spark method has been used for determining strontium in the concentration range 1-100 g/ml in yttrium-90 solutions containing 0,5 % or thereabouts of ammonium citrate. The influence of the citric acid as well as the ammonium citrate with regard to 2N HCL solutions has been studied: the citric acid enhances the line intensities of strontium. The employment of either barium or lanthanum as reference element compensates for this enhancement. Because of the increase in sensitivity mentioned above, the study of influence of the citric acid has been extended and several impurities usually determined in radioisotope solutions have been considered. (Author) 4 refs

Rapid method for the radioactive strontium determination in natural samples; Brza metoda za odredjivanje radioaktivnog stroncija u prirodnim uzorcima

Energy Technology Data Exchange (ETDEWEB)

Grahek, Z; Kosutic, K; Lulic, S [Rudjer Boskovic Institute, Zagreb (Croatia)

1997-12-31

Radioactive strontium isotopes belong to the group of isotopes that are very dangerous for human health. Therefore radioactive strontium is regularly determined in natural samples. When determining strontium isotopes in natural samples, it is necessary to isolate strontium from the sample because strontium isotopes are pure {beta}-emitters. As natural samples contain much more calcium and sodium than strontium it is necessary to isolate a small quantity of strontium from large sample with simultaneous separation of calcium and other interfering elements. For this purposes an elegant method based on ion exchange chromatography has been developed. Namely, examinations with model system have shown that strontium may be separated from calcium on the column filled with anion exchanger and the mixture of the methanol and nitric acid as eluent. It was also shown that yttrium does not separate from strontium but elutes almost simultaneously with it. Yttrium may be separated from strontium on the column filled with cation exchanger DOWEX 50X8 and nitric acid as eluent. According to the above examinations, the procedure of isolation of strontium and yttrium from natural sample has been created (on assumption that {sup 90}Sr and {sup 90}Y in secular equilibrium in sample). Strontium and yttrium have been isolated from natural sample (standard IAEA A-7) on the column filled with the exchanger AMBERLITE CG-400 and the mixture of methanol and nitric acid as eluent. Strontium and yttrium have been separated on the column with cation exchanger. {sup 90}Sr has been determined through {sup 90}Y by counting the solid yttrium oxalate immediately upon isolation and separation from strontium. {sup 90}Sr has also been determined by counting {sup 90}Sr-{sup 90}Y in secular equilibrium after 15 days. The obtained results of determination of {sup 90}Sr through {sup 90}Y and through secular equilibrium {sup 90}Sr-{sup 90}Y correspond to the declared values of standard. (author). 2 figs., 1

Regulation of strontium migration and translocation in chemical reclamation of acid soils

International Nuclear Information System (INIS)

Velichko, V.A.; Okonskij, A.I.; Shestakov, E.I.; Panov, N.P.

1993-01-01

Results of chemical testing are presented of the local reclamants (ashes of various deposits and ferrochromium plant slags) to study the possibilities of their use for chemical soil reclamation. Attention was paid to the investigation of pollutant (strontium) behaviour in the reclamant-acid soil-plant-ground water system. Tracer method was used, 85 Sr was applied as a label. Prospects of zeolite application to control the strontium behaviour following the reclamant introduction into soil were considered. It was shown that zeolite application permitted to regulate strontium behaviour in the reclamant-soil-plant-ground water system. At that the modified zeolites possessing high Sr selectivity are recommended for application

Normal state and superconductivity of La sub 2-x Sr sub x CuO sub 4-y : various doping effects in Sr-rich samples

Energy Technology Data Exchange (ETDEWEB)

Narasimha Rao, C.V.; Weller, M.T. (Dept. of Chemistry, Univ. of Southampton (United Kingdom)); Lanchester, P.C. (Dept. of Physics, Univ. of Southampton (United Kingdom))

1991-12-01

Doping effects studied in the La{sub 2-x}Sr{sub x}CuO{sub 4} system have mostly been confined to lower concentrations of strontium x<0.25. In this paper we present some of the salient features of various substitional effects in La{sub 2-x}Sr{sub x}CuO{sub 4-y} with particular emphasis given to Sr-rich samples x{>=}0.25. We have studied the effects of niobium and titanium dopings for Cu and compare the results with that of Zn substitution. The effects of titanium and niobium substitutions are quite different and the former is even more deleterious in terms of reducing Tc than is found for zinc. X-ray diffraction showed an increase in 'a' and decrease in 'c' parameters for all dopings. The results are interpreted in terms of the hole concentration and impurity disorder effects. (orig.).

Strontium-90 accumulation in fowl and its migration into egg following chromic intake with forage

International Nuclear Information System (INIS)

Koldaeva, K.A.; Sarapul'tsev, I.A.

1975-01-01

Accumulation of strontium-90 in different organs of hens and its transfer ot eggs have been studied at chronic feeding with the isotope. The feed consisted of potato and wheat grown on plots artificially contaminated with strontium-90. The duration of the experiment is 30 days during which the hens lay 35 eggs. Strontium-90 and calcium are determined in the femur, shoulder, breastbone, skull, rib, vertebrae, and muscles. Determination errors do not exceed 10 and 5% for the isotope and calcium respectively. Concentration of stronium-90 and calcium in different bones and in muscles of laying hens and roosters after a month's feeding with the isotope presented. The isotope concentration in bones of hens 3 to 4 times higher than in bones of roosters while the muscle concentration is similar in both cases. The higher content of strontium-90 per g of bone tissue calcium in hens can be explained by a higher level of calcium metabolism during the laying period. Data on strontium-90 and calcium concentration in eggs are also presented. The bulk of the isotope accumulates in the eggshell (96.4%). One egg contains an average of 31% of the daily strontium intake

Marking pike fry otoliths with alizarin complexone and strontium : an evaluation of methods

DEFF Research Database (Denmark)

Skov, Christian; Grønkjær, P.; Nielsen, C.

2001-01-01

Laboratory experiments demonstrated that both alizarin complexone and strontium are useful in mass marking of pike Esox lucius fry otoliths. Visual detection of alizarin complexone marks was considered more reliable than the quantitative analysis of strontium for differentiating marked and unmarked...

Strontium Removal: Full-Scale Ohio Demonstrations

Science.gov (United States)

The objectives of this presentation are to present a brief overview of past bench-scale research to evaluate the impact lime softening on strontium removal from drinking water and present full-scale drinking water treatment studies to impact of lime softening and ion exchange sof...

A solid oxide fuel cell with a gadolinia-doped ceria anode: Preparation and performance

DEFF Research Database (Denmark)

Marina, O.A.; Bagger, C.; Primdahl, S.

1999-01-01

) electrolyte without detrimental reaction. Single SOFCs comprising the CG4 anode, a composite strontium-doped lanthanum manganite-based cathode and the YSZ electrolyte were manufactured and tested in H-2/H2O and CH4/H2O atmospheres vs. air in the temperature range of 800-1015 degrees C, An area specific....../N-2 = 33/3/64. No carbon deposition was found on CG4 after cell operation at a steam-to-carbon ratio of 0.3 for 1000 h. Cells sustained several rapid thermal cycles in the temperature interval 200-1000 degrees C and a full redox cycle without degradation. (C) 1999 Elsevier Science B.V. All rights...

Bulgarian regional patterns of contamination by global fallout (strontium 90)

International Nuclear Information System (INIS)

Boyadzhiev, A.; Shopov, N.; Simova, G.; Andreev, E.; Mikha lov, M.G.

1980-01-01

For selected districts in the country, mean annual atmospheric precipitation rates were related to strontium-90 contents in milk over the period 1970-1977. Strontium-90 in milk was determined by the method of Popov, using Va-Z-310 counters for activity measurements. The impact of annual precipitation means was examined by monofactorial spread analysis, with sites distributed into three groups according to precipitation rates observed over longer time periods: up to 650 l/m 2 from 650 to 750 l/m 2 ; and above 750 L/M 2 . Values of coefficient F were estimated, representing the ratio of group to random spreads. These figures were compared with critical values in Student's tables for 0.05 significance level. The F data indicated a definite alternative relationship to exist between strontium-90 amounts in mils and annual precipitation rates, which is prognostically meaningful from the strandpoint of radiological protection of the population

Coherent normalization of finger strontium XRF measurements: feasibility and limitations

Energy Technology Data Exchange (ETDEWEB)

Zamburlini, M; Pejovic-Milic, A; Chettle, D R [Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, L8S 4K1 (Canada)

2008-08-07

A non-invasive in vivo x-ray fluorescence (XRF) method of measuring bone strontium concentrations has previously been reported as a potential diagnostic tool able to detect strontium concentration in the finger and ankle bones. The feasibility of coherent normalization for {sup 125}I-source-based finger bone strontium x-ray fluorescence (XRF) measurements is assessed here by theoretical considerations and Monte Carlo simulations. Normalization would have several advantages, among which are the correction for the signal attenuation by the overlying soft tissue, and intersubject variability in the bone size and shape. The coherent normalization of bone strontium XRF measurements presents several challenges dictated by the behaviour of the coherent cross section and mass attenuation coefficient at the energies involved. It was found that the coherent normalization alone with either 22.1 keV or 35.5 keV photons was not successful in correcting for the overlying soft tissue attenuation. However, it was found that the coherent peak at 35.5 keV was able to correct effectively for variability in the finger bone size between people. Thus, it is suggested that, if the overlying soft tissue thickness can be obtained by means of an independent measurement, the 35.5 keV peak can be used to correct for the bone size, with an overall accuracy of the normalization process of better than 10%. (note)

Origin of absorption peaks in reflection loss spectrum in Ku- frequency band of Co-Zr substituted strontium hexaferrites prepared using sucrose precursor

Energy Technology Data Exchange (ETDEWEB)

Narang, Sukhleen Bindra, E-mail: sukhleen2@yahoo.com [Department of Electronics Technology, Guru Nanak Dev University, Amritsar (India); Pubby, Kunal, E-mail: kunalpubby02@gmail.com [Department of Electronics Technology, Guru Nanak Dev University, Amritsar (India); Chawla, S.K., E-mail: sschawla118@gmail.com [Department of Chemistry, Centre for Advanced Studies-I, Guru Nanak Dev University, Amritsar (India); Kaur, Prabhjyot, E-mail: prabhjyot.2525@gmail.com [Department of Chemistry, Centre for Advanced Studies-I, Guru Nanak Dev University, Amritsar (India)

2017-03-15

This study presents the detailed explanation of the factors, contributing towards the absorption peaks in reflection loss spectrum of hexaferrites. Cobalt-Zirconium substituted strontium hexaferrites, synthesized using sucrose precursor sol-gel technique, were analyzed in 12.4–18 GHz frequency range. The concepts of impedance matching through quarter wavelength condition, complex thickness, dielectric phase angle and attenuation constant have been used to determine the location as well as intensity of absorption peaks. This study also demonstrates the potential application of three compositions of this series with doping content (x)==0.0, 0.6 and 0.8 as an effective microwave absorbers in Ku-frequency band. - Highlights: • EM analysis of Sr Hexaferrites in Ku-band. • Factors towards absorption peak intensity & location.

Near-infrared quantum cutting in Yb3+ ion doped strontium vanadate

Science.gov (United States)

Sawala, N. S.; Bajaj, N. S.; Omanwar, S. K.

2016-05-01

The materials Sr3-x(VO4)2:xYb were successfully synthesized by co-precipitation method varying the concentration of Yb3+ ions from 0 to 0.06 mol. It was characterize by powder X-ray powder diffraction (XRD) and surface morphology was studied by scanning electronic microscope (SEM). The photoluminescence (PL) properties were studied by spectrophotometers in near infra red (NIR) and ultra violet visible (UV-VIS) region. The Yb3+ ion doped tristrontium vanadate (Sr3(VO4)2) phosphors that can convert a photon of UV region (349 nm) into photons of NIR region (978, 996 and 1026 nm). Hence this phosphor could be used as a quantum cutting (QC) luminescent convertor in front of crystalline silicon solar cell (c-Si) panels to reduce thermalization loss due to spectral mismatch of the solar cells. The theoretical value of quantum efficiency (QE) was calculated from steady time decay measurement and the maximum efficiency approached up to 144.43%. The Sr(3-x) (VO4)2:xYb can be potentiality used for betterment of photovoltaic (PV) technology.

Tuning of electronic band gaps and optoelectronic properties of binary strontium chalcogenides by means of doping of magnesium atom(s)- a first principles based theoretical initiative with mBJ, B3LYP and WC-GGA functionals

Science.gov (United States)

Debnath, Bimal; Sarkar, Utpal; Debbarma, Manish; Bhattacharjee, Rahul; Chattopadhyaya, Surya

2018-02-01

First principle based theoretical initiative is taken to tune the optoelectronic properties of binary strontium chalcogenide semiconductors by doping magnesium atom(s) into their rock-salt unit cells at specific concentrations x = 0.0, 0.25, 0.50, 0.75 and 1.0 and such tuning is established by studying structural, electronic and optical properties of designed binary compounds and ternary alloys employing WC-GGA, B3LYP and mBJ exchange-correlation functionals. Band structure of each compound is constructed and respective band gaps under all the potential schemes are measured. The band gap bowing and its microscopic origin are calculated using quadratic fit and Zunger's approach, respectively. The atomic and orbital origins of electronic states in the band structure of any compound are explored from its density of states. The nature of chemical bonds between the constituent atoms in each compound is explored from the valence electron density contour plots. Optical properties of any specimen are explored from the computed spectra of its dielectric function, refractive index, extinction coefficient, normal incidence reflectivity, optical conductivity optical absorption and energy loss function. Several calculated results are compared with available experimental and earlier theoretical data.

Strontium concentration in the Baltic Sea in 1974-1975 and its correlation with some hydrodynamic characteristics

International Nuclear Information System (INIS)

Stankajtis, A.K.; Styro, D.B.

1978-01-01

Strontium concentration data in the surface and deep layers of the Baltic Sea water are presented. Strontium concentration in the surface layer varies from 1.6 mg/1 to 2.2 mg/1 and that at a depth of 50 m - from 2.0 to 3.2 mg/1. Maximum concentration (4.5 mg/1) is at a depth of 440 m. Strontium concentration data are correlated with some hydrometeorological parameters (wind velocity and direction, water temperature, salinity). It has been indicated that water mass transfer in the Baltic Sea may be traced using the data on strontium concentration variations

Recovery and separation of rare-earth elements, barium, and strontium from bastnasite with sulfuric acid

International Nuclear Information System (INIS)

Eisele, J.A.; Bauer, D.J.

1974-01-01

A bench-scale investigation was made of a concentrated H 2 SO 4 reaction for recovering and separating rare earth elements, barium, and strontium from a bastnaesite ore and byproduct. Barium and strontium were dissolved in the concentrated acid and precipitated as a mixed product by water dilution. Separation of strontium from barium was effected by reaction with Na 2 CO 3 solution, followed by a dilute acid leach of the SrCO 3 formed. After removing the barium and strontium from bastnaesite ore, the rare-earth elements were roasted to water-soluble sulfates. The rare earth sulfate solution was subsequently processed by solvent extraction to produce rare-earth oxides low in lead and magnesium. (U.S.)

ADSORPTION OF STRONTIUM IONS FROM WATER ON MODIFIED ACTIVATED CARBONS

Directory of Open Access Journals (Sweden)

Mihai Ciobanu

2016-12-01

Full Text Available Adsorption of strontium ions from aqueous solutions on active carbons CAN-7 and oxidized CAN-8 has been studied. It has been found that allure of the adsorption isotherms for both studied active carbons are practically identical. Studies have shown that the adsorption isotherms for strontium ions from aqueous solutions are well described by the Langmuir and Dubinin-Radushkevich equations, respectively. The surface heterogeneity of activated carbons CAN-7 and oxidized CAN-8 has been assessed by using Freundlich equation.

Application of empore TM strontium rad disks to the analysis of radiostrontium in environmental water samples

International Nuclear Information System (INIS)

Smith, L.L.; Seely, D.C.; Shannon, R.T.

1996-01-01

A solid phase extraction method for analyzing radioactive strontium in surface, ground, and drinking waters is presented. Strontium is simply isolated by pulling an acidified sample aliquot through an Empore TM strontium rad disk with a vacuum, and the disk is subsequently assayed for beta activity. The method is efficient, safe, reliable, and potentially field deployable. Sample preparation and counting source preparation may be condensed into a single procedure, thereby improving efficiency and eliminating many potential sources of laboratory error. Moreover, many of the hazardous chemicals associated with traditional strontium procedures are eliminated. Samples are easily batched, and a one-liter sample may be prepared with as little as 20 min of effort. For a one-liter aqueous sample, up to 3 mg of strontium can be retained by the disks. Chemical and radiometric interferences are discussed. (orig.)

Determination of lithium, rubidium and strontium in foodstuffs

International Nuclear Information System (INIS)

Evans, W.H.; Read, J.I.

1985-01-01

For the determination of total lithium, rubidium and strontium in foodstuffs the organic matter is destroyed by a wet-oxidation procedure. Both lithium and rubidium are measured by flame atomic-emission spectrophotometry, rubidium with the addition of a radiation buffer and strontium is measured by flame atomic-absorption spectrophotometry using the same radiation buffer. The optimum conditions for measurement are described and interferences noted. The accuracy of the method was assessed by measuring the recovery of these metals from foodstuff homogenates and values for standard reference materials are listed, for comparison with certified levels where these exist. From the results obtained standard deviations were calculated and derived limits of detection and confidence intervals are given. (author)

Determination of the thermal radiation effect on an optical strontium lattice clock; Bestimmung des Einflusses thermischer Strahlung auf eine optische Strontium-Gitteruhr

Energy Technology Data Exchange (ETDEWEB)

Middelmann, Thomas

2013-05-31

Optical clocks have the potential to be 100 times more accurate than current best cesium atomic clocks within a fraction of the averaging time. This corresponds to a fractional uncertainty of the clock frequency on the level of 10{sup -18} and requires highaccuracy knowledge of systematic frequency shifts, such that they can be avoided or corrected for. In strontium optical lattice clocks an ensemble of ultracold strontium atoms is confined in an optical lattice, to allow for spectroscopy of the reference transition 5s{sup 2} {sup 1}S{sub 0}-5s5p {sup 3}P{sub 0} in the Lamb-Dicke regime. The by far largest systematic frequency shift of the strontium clock transition is caused by its high sensitivity to blackbody radiation (BBR). The knowledge of the resulting frequency shift limited the achievable clock uncertainty to about 1 x 10{sup -16}. In this thesis for the first time an experimental approach was followed, to determine the sensitivity of the strontium clock transition to blackbody radiation. At an environmental temperature of 300 K the resulting frequency shift corresponds to 2.277 8(23) Hz. The achieved uncertainty contributes with 5 x 10{sup -18} to the fractional systematic uncertainty of the clock frequency. The determination is based on a precision measurement of the difference of static polarizabilities of the two clock states {Delta}{alpha}{sub dc} = {alpha}(5s5p {sup 3}P{sub 0})-{alpha}(5s{sup 2} {sup 1}S{sub 0}) = 4.078 73(11) x 10{sup -39} Cm{sup 2} /V. For this the de Stark shift of the clock transition has been measured in the accurately known electric field of a precision plate capacitor, which has been developed in this work. The attained static polarizability difference {Delta}{alpha}{sub dc} corresponds to the first term of a power series of the sensitivity to BBR. Higher orders are accumulated as dynamic part of the BBR shift. Which has been modelled using {Delta}{alpha}{sub dc} and experimental data for other atomic properties. To

Incorporation of silver and strontium in hydroxyapatite coating on titanium surface for enhanced antibacterial and biological properties

Energy Technology Data Exchange (ETDEWEB)

Geng, Zhen [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Wang, Renfeng [School of Laboratory Medicine, Tianjin Medical University, Tianjin 300072 (China); Zhuo, Xianglong, E-mail: doctorzhuo@139.com [Department of Spinal Surgery, Liuzhou Worker' s Hospital, Liuzhou 545001 (China); Li, Zhaoyang, E-mail: zyli@tju.edu.cn [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); Huang, Yongcan [Orthopedics Research Center, Peking University Shenzhen Hospital, Shenzhen 518036 (China); Ma, Lili; Cui, Zhenduo [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Zhu, Shengli [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); Liang, Yanqin [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Liu, Yunde; Bao, Huijing; Li, Xue; Huo, Qianyu; Liu, Zhili [School of Laboratory Medicine, Tianjin Medical University, Tianjin 300072 (China); Yang, Xianjin, E-mail: xjyang@tju.edu.cn [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China)

2017-02-01

Implant-related infection in primary total joint prostheses has attracted considerable research attention. As a measure to improve the antimicrobial properties of implant materials, silver (Ag) was incorporated into calcium phosphate (CaP) coatings on Titanium (Ti) via a hydrothermal method. Further, strontium (Sr) was added as a binary dopant to reduce the cytotoxicity of Ag in the coatings. Results showed that the CaP coatings were uniformly deposited on Ti with enhanced hydrophilicity and nanoscale surface roughness. Moreover, cell adhesion, proliferation, and differentiation were improved after the CaP coating deposition. The antibacterial properties of the coatings were distinctly improved by the incorporation of Ag, but the cell proliferation and differentiation were significantly decreased. Owing to the incorporation of Sr, the Ag-CaP coatings were able to effectively counteract the negative effects of Ag while maintaining good antibacterial properties. In summary, hydrothermally deposited CaP coatings doped with Ag and Sr exhibit excellent biocompatibility and antimicrobial activity. Thus, such co-doped CaP coatings have considerable potential for orthopaedic implant modification. - Highlights: • Ag- and Sr-substituted HA coating is deposited on titanium by hydrothermal method. • This coating shows a remarkable antibacterial activity and good biocompatibility. • The coating process is simple and suitable for large-scale fabrication. • The possible mechanism of Sr{sup 2+} is proposed.

Strontium-90 and cesium-137 in freshwater (from September, 1982, to December, 1982)

International Nuclear Information System (INIS)

1982-01-01

Strontium-90 and cesium-137 in fresh water measured at 4 locations across Japan from September to December, 1982, are given in pCi/l, respectively. The methods of the collection and pretreatment of samples, the preparation of samples for analysis, the separation of strontium-90 and cesium-137, and the counting are also described. The sample was passed through a cation exchange column. Strontium and cesium were eluted with hydrochloric acid from the cation exchange column. The sample solution prepared was neutralized with sodium hydroxide. After sodium carbonate was added, the precipitate of strontium and calcium carbonates was separated. The supernatant solution was retained for cesium-137 determination. After the radiochemical separation, the mounted precipitate was counted for activity using a low background beta counter normally for 60 min. The radioactivity ranged 0.08 to 0.22 pCi/l for Sr-90 and 0.003 to 0.020 pCi/l for Cs-137 in the freshwater. (J.P.N.)

Microwave-hydrothermal synthesis of barium strontium titanate nanoparticles

International Nuclear Information System (INIS)

Simoes, A.Z.; Moura, F.; Onofre, T.B.; Ramirez, M.A.; Varela, J.A.; Longo, E.

2010-01-01

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 o C. - Abstract: Hydrothermal-microwave method (HTMW) was used to synthesize crystalline barium strontium titanate (Ba 0.8 Sr 0.2 TiO 3 ) nanoparticles (BST) in the temperature range of 100-130 o C. The crystallization of BST with tetragonal structure was reached at all the synthesis temperatures along with the formation of BaCO 3 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.

Resonant double photoionisation spectroscopy of strontium

Energy Technology Data Exchange (ETDEWEB)

Sokell, E; Grimm, M; Sheridan, P, E-mail: emma.sokell@ucd.i, E-mail: paul.sheridan@ucd.i [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland)

2009-11-01

Resonant triple-differential cross-section (TDCS) measurements on atomic strontium on the 4p {yields} 4d resonance are presented. All of these TDCS measurements display unexpected lobes at a mutual emission angle for the two electrons of 180{sup o}. Possible explanations for these lobes are explored.

Spontaneous reossification of the sella in transsphenoidal reoperation associated with strontium ranelate

Directory of Open Access Journals (Sweden)

Maria Mercedes Pineyro

2017-07-01

Full Text Available Spontaneous reossification of the sellar floor after transsphenoidal surgery has been rarely reported. Strontium ranelate, a divalent strontium salt, has been shown to increase bone formation, increasing osteoblast activity. We describe an unusual case of a young patient with Cushing’s disease who was treated with strontium ranelate for low bone mass who experienced spontaneous sellar reossification after transsphenoidal surgery. A 21-year-old male presented with Cushing’s features. His past medical history included delayed puberty diagnosed at 16 years, treated with testosterone for 3 years without further work-up. He was diagnosed with Cushing’s disease initially treated with transsphenoidal surgery, which was not curative. The patient did not come to follow-up visits for more than 1 year. He was prescribed strontium ranelate 2 g orally once daily for low bone mass by an outside endocrinologist, which he received for more than 1 year. Two years after first surgery he was reevaluated and persisted with active Cushing’s disease. Magnetic resonance image revealed a left 4 mm hypointense mass, with sphenoid sinus occupation by a hyperintense material. At repeated transsphenoidal surgery, sellar bone had a very hard consistency; surgery was complicated and the patient died. Sellar reossification negatively impacted surgery outcomes in this patient. While this entity is possible after transsphenoidal surgery, it remains unclear whether strontium ranelate could have affected sellar ossification.

Research on a pellet co-precipitation micro-filtration process for the treatment of liquid waste containing strontium

International Nuclear Information System (INIS)

Xin Luo; North China Institute of Science and Technology, Beijing; Guanghui Zhang; Xue Wang; Ping Gu

2013-01-01

The chemical precipitation method for radioactive wastewater treatment has the advantages of being simple and cost-effective. However, difficulties with the solid–liquid separation and sludge concentration restrict the application of this method. In this paper, a pellet co-precipitation micro-filtration (PCM) process was studied for treating strontium-containing wastewater on a laboratory scale. The seed was prepared by CaCO 3 powders. Sr 2+ and CO 3 2- were constantly crystallised on the seed surface, with Na 2 CO 3 as the precipitating agent in the pellet reactor. The following membrane separator with the addition of FeCl 3 enhanced the treatment effect. The average strontium concentrations in the raw water and in the effluent were 12.0 and 0.0220 mg/L, respectively. The strontium decontamination factor (DF) increased with the operation time, with an average value of 577. The precipitate particles formed gradually grew larger, with good sedimentation properties. When the experiment was complete, the formed precipitate was separated easily from the liquid phase and directly discharged. The concentration factor (CF) was 1,958. In the PCM process, crystallisation was the main mechanism for strontium removal, with the influent strontium level playing an important role. Membrane pore blockage and cake layer formation could help to further intercept the strontium crystallites. Furthermore, ferric chloride coagulation in the membrane separator also contributed to strontium removal. The PCM process has potential for wider application in the removal of strontium from wastewater. (author)

Sr-89 therapy: strontium kinetics in disseminated carcinoma of the prostate.

Science.gov (United States)

Blake, G M; Zivanovic, M A; McEwan, A J; Ackery, D M

1986-01-01

Strontium kinetics were investigated in a group of 14 patients receiving 89Sr palliation for metastatic bone disease secondary to prostatic carcinoma. Using 85Sr as a tracer, total body strontium retention R(t) was monitored for a 3 month period following 89Sr administration, and at 90 days was found to vary from 11% to 88% and to correlate closely with the fraction of the skeleton showing scintigraphic evidence of osteoblastic metastatic involvement. Strontium renal plasma clearance varied from 1.6 l/day to 11.6 l/day, and in nine patients was significantly reduced compared with values found in healthy adult men, probably due to increased renal tubular reabsorption associated with the disturbance of calcium homoeostasis. Renal clearance rate was the principal factor determining R(t) for t less than 6 days, and was an important secondary factor at later times. Over the interval 30 days less than t less than 90 days, R(t) was closely fitted by the power law function R(t) = R30 (t/30)-b, with R30 and b showing the close correlation expected from the effect of R(t) on strontium recycling. The correction of the data for this effect to determine the true skeletal release rate is described. Measurement of localized strontium turnover in individual metastatic deposits from whole body profiles and scintigraphic images gave retention curves that typically rose to a plateau by 10 days after therapy, and then decreased very slowly. In contrast, retention curves for adjacent normal trabecular bone showed more rapid turnover, peaking at 1 day and subsequently decreasing following a t-0.2 power law function.(ABSTRACT TRUNCATED AT 250 WORDS)

Migration of strontium-90 from a strontium-90 fluoride deep ocean source

International Nuclear Information System (INIS)

Yabusaki, S.

1981-06-01

A hypothetical rupture of a heat source capsule on the ocean floor is analyzed for strontium-90 migration and attenuation. The evolution of the three-dimensional contaminant plume is simulated by a modified version of the Okubo-Pritchard radially symmetrical, diffusion velocity dispersion model. Results from this study indicate that released solutes are confined vertically to a layer near the level of introduction. Along the plume centerline, however, water quality is affected for considerably distances downstream from the source, with the maximum effect occurring after one year

Solid solution barium–strontium chlorides with tunable ammonia desorption properties and superior storage capacity

DEFF Research Database (Denmark)

Bialy, Agata; Jensen, Peter Bjerre; Blanchard, Didier

2015-01-01

with spray drying and in situ thermogravimetric and structural characterization, we synthesize a range of new, stable barium-strontium chloride solid solutions with superior ammonia storage densities. By tuning the barium/strontium ratio, different crystallographic phases and compositions can be obtained...... with different ammonia ab- and desorption properties. In particular it is shown, that in the molar range of 35–50% barium and 65–50% strontium, stable materials can be produced with a practically usable ammonia density (both volumetric and gravimetric) that is higher than any of the pure metal halides...

Decorporation of mixture of strontium and cesium isotopes with domestic mineral waters

International Nuclear Information System (INIS)

Slavov, S.; Filev, G.; Kiradzhiev, G.

1990-01-01

The possibilities of Bulgarian mineral waters to decorporate mixtures of strontium and cesium radioisotopes, simultaneous entering the body, were studied. A modified effect in respect to radioactive strontium was found. Modification of the effect of mixing two diferent types of mineral waters was not proven. No effect was found of potassium-containing mineral water on radioactive cesium kinetics. 1 tab., 7 refs

Summary of Research Activities Academic Departments 1980-1981.

Science.gov (United States)

1981-10-01

Na - salts of nickel (II) undecatungsto- gallate (III) were prepared and analyzed for all constituents except constitutional oxygen. The...Mary C. WINTERSGILL, Assistant Professor, "The Activation "olume for Type I Dipoles in Lanthanum Doped Strontium ioride," Journal of Physics C: Solid...State Physics 13 (1980) 3449-3455. The audio frequency complex dielectric constant has been measured for lanthanum -doped strontium fluoride at

Strontium hydroxyapatite and strontium carbonate as templates for the precipitation of calcium-phosphates in the absence and presence of fluoride

Science.gov (United States)

Sternitzke, Vanessa; Janousch, Markus; Heeb, Michèle B.; Hering, Janet G.; Johnson, C. Annette

2014-06-01

The heterogeneous precipitation of calcium-phosphates on calcium hydroxyapatite (Ca10(PO4)6(OH)2 or HAP) in the presence and absence of fluoride is important in the formation of bone and teeth, protection against tooth decay, dental and skeletal fluorosis and defluoridation of drinking water. Strontium hydroxyapatite (Sr10(PO4)6(OH)2 or SrHAP) and strontium carbonate (SrCO3) were used as calcium-free seed templates in precipitation experiments conducted with varying initial calcium-to-phosphate (Ca/P) or calcium-to-phosphate-to-fluoride (Ca/P/F) ratios. Suspensions of SrHAP or SrCO3 seed templates (which were calcium-limited for both templates and phosphate-limited in the case of SrCO3) were reacted at pH 7.3 (25 °C) over 3 days. The resulting solids were examined with Scanning Transmission Electron Microscopy (STEM), X-ray Diffraction (XRD), Fourier Transform Infrared (FTIR), and X-ray Photoelectron Spectroscopy (XPS), X-ray Absorption Near Edge Structure (XANES), and Extended X-ray Absorption Fine Structure spectroscopy (EXAFS). Calcium apatite was the predominant phase identified by all techniques independent of the added Ca/P ratios and of the presence of fluoride. It was not possible to make an unambiguous distinction between HAP and fluorapatite (Ca10(PO4)6F2, FAP). The apatite was calcium-deficient and probably contained some strontium.

A distribution ratio model of strontium by crown ether extraction from simulated HLLW

International Nuclear Information System (INIS)

Chen Jing; Wang Qiuping; Wang Jianchen; Song Chongli

1995-01-01

An experiential distribution ratio model for strontium extraction by dicyclohexano-18-crown-6-n-octanol from simulated high-level waste is established. The experimental points for the model are designed by experimental homogeneous-design method. The regression of distribution ratio model of strontium is carried out by the complex-optimization method. The model is verified with experimental distribution ratio data in different extraction conditions. The results show that the relative deviations are within +-10% and the mean relative divination is 4.4% between the calculated data and the experimental ones. The experiential model together with an iteration program can be used for the strontium extraction process calculation

Dielectric behaviour of strontium tartrate single crystals

Indian Academy of Sciences (India)

Unknown

dielectric loss (tan δ) as functions of frequency and temperature. Ion core type ... Since the data on dielectric properties of strontium tartrate trihydrate (STT) do not ... through 'AE' make 15-amp dimmerstat, the rate of heating was maintained ...

X-ray fluorescence analysis of strontium in environmental water by using barium carbonate coprecipitation method

International Nuclear Information System (INIS)

Nishioka, Hiroshi; Yoneda, Akio; Maeda, Yoshimichi; Azumi, Takatugu

1986-01-01

Determination of strontium in environmental water was studied by a coprecipitation method with barium carbonate and the subsequent X-ray fluorescence analysis. Fifty mg of barium ion and 1 g of sodium carbonate were added to sample water, which was then mixed for one hour by a magnetic stirrer. Precipitate was gathered onto a membrane filter paper to measure its XF intensity. The amount of strontium from 2 to 150 μg could be repeatedly determined by means of the calibration curve method, and the limit of detection was found to be 0.6 μg of strontium. A large amount of calcium and magnesium ions was found to interfere with the coprecipitation of strontium ion. However, this interference could be eliminated by using a small amount of sample water. Strontium in several environmental waters was determined by the above method. The results obtained from the calibration curve method and the standard addition method agreed with each other, and also agreed with those from the atomic absorption spectrometry. (author)

Improved efficiency of dye-sensitized solar cells by doping of strontium aluminate phosphor in TiO2 photoelectrode

Directory of Open Access Journals (Sweden)

Hwangbo Seung

2015-06-01

Full Text Available SrAl2O4:Eu2+, Dy3+ phosphor was synthesized by chemical solution route to use as a dopant in TiO2 layer employed as a photoelectrode for down conversion of ultraviolet and near-ultraviolet to visible and near-infrared light in a dye-sensitized solar cell. Nano-crystalline structure of the SrAl2O4:Eu2+, Dy3+ powder was confirmed by X-ray diffraction analysis and field emission scanning electron microscopy. Monitored at 520 nm, SrAl2O4:Eu2+, Dy3+ phosphor showed emission peaks at 460 to 610 nm due to 4f6 4f7 transitions of Eu2+ ions. For the study, SrAl2O4:Eu2+, Dy3+ phosphor-doped TiO2 layer was deposited on fluorine-doped tin oxide coated glass by electrostatic spray deposition. The short circuit current, open circuit voltage, fill factor, and conversion efficiency of the cells were measured. Experimental results revealed that the device efficiency for the SrAl2O4:Eu2+, Dy3+ phosphor-doped TiO2 layer increased to 7.20 %, whereas that of the pure-TiO2 photoelectrode was 4.13 %.

Improved ferroelectric and pyroelectric properties of Pb-doped SrBi4Ti4O15 ceramics for high temperature applications

International Nuclear Information System (INIS)

Venkata Ramana, E.; Graça, M.P.F.; Valente, M.A.; Bhima Sankaram, T.

2014-01-01

Highlights: • Sr 1−x Pb x Bi 4 Ti 4 O 15 (SPBT, x = 0 − 0.4) ceramics were synthesized by soft chemical method. • X-ray diffraction analysis confirmed the formation of bismuth layered structure. • SEM images showed plate like grain morphology with random orientation of plate faces. • Pb-doping resulted in improved ferroelectricity of SrBi 4 Ti 4 O 15 ceramics. • Pb-doped SrBi 4 Ti 4 O 15 exhibited improved pyroelectric properties with high T C . -- Abstract: Ferroelectric properties of Pb-modified strontium bismuth titanate ceramics with chemical formula Sr 1−x Pb x Bi 4 Ti 4 O 15 (x = 0–0.4) were investigated. Polycrystalline ceramics were synthesized by soft chemical method to study the effect of Pb-doping on its physical properties. X-ray diffraction analysis revealed a bismuth layered structure for all the compounds. The doping resulted in an increased tetragonal strain and improved ferroelectric properties. Scanning electron microscope images showed plate like grain morphology with random orientation of platelets. The ferroelectric transition temperature of the ceramics increased systematically from 525 °C to 560 °C with the increase of doping concentration. The piezoelectric coefficient (d 33 ) of the ceramics was enhanced significantly with Pb doping, exhibiting a maximum value of 21.8 pC/N for 40 mol.% Pb-doped SBT. Pyroelectric studies carried out using the Byer–Roundy method indicated that the modified SBT ceramics are promising candidates for high temperature pyroelectric applications

Investigation of the process of co-crystallization of barium and strontium nitrates from the system acetic acid-water

International Nuclear Information System (INIS)

Hubicki, W.; Piskorek, M.

1976-01-01

Co-crystallization of barium nitrate and strontium nitrate from the system CH 3 COOH-H 2 O was investigated by using radioactive tracer Ba 133 . The authors have found that during the crystallization of strontium nitrate from acetic acid solution at 25 0 C, one can obtain a 67-fold lowering of the content of barium in strontium nitrate, a 40-fold lowering of the content of barium in strontium nitrate is at 35 0 C. Strontium nitrate went to the solid phase with 70% efficiency. Acetic acid solutions of 24.5-24.3 per cent weight were used. Attention was paid to the franctionation of barium admixtures during crystallization of strontium nitrate from acetic acid solutions (so called ''isothermic salting out crystallization process'') is in agreement with the logarithmic law of Doerner-Hoskins. Process is characterized by a constant coefficient of surface co-crystallization lambda = 18. The results of investigations show that it is possible to obtain spectrally pure non-barium strontium nitrate as the result of its crystallization from the system CH 3 COOH-H 2 O at a temperature of 25 0 and 35 0 C. (author)

Strontium-90 and cesium-137 in soil from May to July 1983

International Nuclear Information System (INIS)

1983-01-01

The measured values in soil of strontium-90 and cesium-137 at a total of 4 locations throughout Japan from May to July, 1983 are given in pCi/kg and mCi/km 2 in the tables. The method of measurement is also described: collection and pretreatment of samples, preparation of the samples for analysis, separation of strontium-90 and cesium-137, determination of stable strontium, calcium and potassium, and counting. Soil was collected from the location in the spacious and flat area without any past disturbance. Soil was taken from two layers having different depths: 0--5 cm and 5--20 cm. The sample solution was neutralized with sodium hydroxide. After sodium carbonate was added, the precipitate of strontium and calcium carbonates was separated. The supernatant solution was retained for cesium-137 determination. After the radiochemical separation, the mounted precipitates were counted for activity using a low background beta counter normally for 60 min. The maximum values were 690 pCi/kg for Sr-90 and 1300 pCi/kg for Cs-137, which were obtained from the samples in the 5-to-20 cm depth, in June 1983, at Akita-ken,Japan. (Mori, K.)

Strontium cobaltite oxygen sponge catalyst and methods of use

Energy Technology Data Exchange (ETDEWEB)

Lee, Ho Nyung; Jeen, Hyoungjeen; Choi, Woo Seok; Biegalski, Michael; Folkman, Chad M.; Tung, I-Cheng; Fong, Dillon D.; Freeland, John W.; Shin, Dongwon; Ohta, Hiromichi; Chisholm, Matthew F.

2017-01-24

Rapid, reversible redox activity may be accomplished at significantly reduced temperatures, as low as about 200.degree. C., from epitaxially stabilized, oxygen vacancy ordered SrCoO.sub.2.5 and thermodynamically unfavorable perovskite SrCoO.sub.3-.delta.. The fast, low temperature redox activity in SrCoO.sub.3-.delta. may be attributed to a small Gibbs free energy difference between the two topotactic phases. Epitaxially stabilized thin films of strontium cobaltite provide a catalyst adapted to rapidly transition between oxidation states at substantially low temperatures. Methods of transitioning a strontium cobaltite catalyst from a first oxidation state to a second oxidation state are described.

Development of a strontium chronic effects benchmark for aquatic life in freshwater.

Science.gov (United States)

McPherson, Cathy A; Lawrence, Gary S; Elphick, James R; Chapman, Peter M

2014-11-01

There are no national water-quality guidelines for strontium for the protection of freshwater aquatic life in North America or elsewhere. Available data on the acute and chronic toxicity of strontium to freshwater aquatic life were compiled and reviewed. Acute toxicity was reported to occur at concentrations ranging from 75 mg/L to 15 000 mg/L. The majority of chronic effects occurred at concentrations above 11 mg/L; however, calculation of a representative benchmark was confounded by results from 4 studies indicating that chronic effects occurred at lower concentrations than all other studies, in 2 cases below background concentrations reported for US and European streams. Two of these studies, including 1 reporting effects below background concentrations, were repeated and found not to be reproducible; chronic effects occurred at considerably higher strontium concentrations than in the original studies. Studies with narrow-mouthed toad and goldfish were not repeated; both studies reported chronic effects below background concentrations, and both studies had been conducted by the authors of 1 of the 2 studies that were repeated and shown to be nonreproducible. Studies by these authors (3 of the 4 confounding studies), conducted over 30 yr ago, lacked detail in reporting of methods and results. It is thus likely that repeating the toad and goldfish studies would also have resulted in a higher strontium effects concentration. A strontium chronic effects benchmark of 10.7 mg/L that incorporates the results of additional testing summarized in the present study is proposed for freshwater environments. © 2014 SETAC.

States of atoms and interatomic interactions in complex perovskite-like oxides. Communication XXIII. Magnetic dilution in the La(Sr)NiO3-LaGaO3

International Nuclear Information System (INIS)

Chezhina, N.V.; Bodritskaya, Eh.V.; Zhuk, N.A.

2008-01-01

Magnetic susceptibility of dilute solid solutions of lanthanum gallates doped with nickel and also with nickel and strontium was studied. Calculations showed that the main contribution into the exchange interactions in gallates doped with nickel is made by dimers formed by low-spin nickel(III) (J -20 cm -1 ), and in gallates doped with strontium and nickel the main contribution is due to dimers formed by high-and low-spin nickel (J 10 cm -1 ). Electrical conductivity measurements showed that the samples under study are electron and ion conductors [ru

Deposition of caesium and strontium substances on growing crops: Effects and countermeasures

International Nuclear Information System (INIS)

Bengtsson, S.

2010-01-01

Full text: To investigate how the two radionuclides caesium ( 134 Cs) and strontium ( 85 Sr) are taken up and transported to the harvested parts (the seeds) by fallout in a growing crop. Further on how this is related to the size and time of the fallout. From the information collected recommendation of suitable countermeasures at different scenarios to prevent further spreading to food stuff can be suggested. In the project a number of field trials where artificial deposited by the two radionuclides 134 Cs and 85 Sr in a contaminated rainfall, on the two agricultural crops Brassica napus L. (spring rape) and Triticum aestivum L. (spring wheat). The trial contained different treatments where the radionuclides where deposited by a rainfall simulator at different growing stages of the crops. The field trial continues for two more years and the reason for that is due to the variation of the climate for the different years. The radionuclides were applied in the form of a wet deposition and the rainfall was about 1 mm m -1 with a concentration of 20 kBq m -1 for each radionuclide. Samples were taken from the plots at the day(s) after the treatment of contaminated rainfall, both from the latest treated plots and from the earlier treated plots. The hypotheses are: 1. That the size of the deposition and the time in relation to the development stages of the crop will steer how much caesium and strontium that are coughed, detained and transferred to the harvested parts. 2. That the levels of caesium and strontium in the harvested parts of the crops are related to the insensitivity of the rainfall after a deposition and also how long time the first intensive rain will occur. 3. That the size of caesium and strontium in harvested plant parts are related to the size of uptake throw the leaves. 4. If the deposition of caesium and strontium will be the same, the levels of caesium will be much higher than strontium in the harvested parts. (author)

Structural, optical and gas sensing properties of screen-printed nanostructured Sr-doped SnO2 thick film sensor

International Nuclear Information System (INIS)

Shaikh, F.I.; Chikhale, L.P.; Patil, J.Y.; Rajgure, A.V.; Suryavanshi, S.S.; Mulla, I.S.

2013-01-01

The nanocrystalline materials of strontium doped tin oxide powders were synthesized by conventional co-precipitation method. Synthesized nanophase SnO 2 powders were used to fabricate thick films of pure and Sr-doped SnO 2 using screen-printing technology and investigated for their gas sensing properties towards LPG, ethanol, ammonia and acetone vapor. The crystal structure and phase of the sintered powders were characterized by X-ray diffractometer (XRD) and microstructure by scanning electron microscopy (SEM). All the doped and undoped SnO 2 compositions revealed single phase and solid solution formation. X-ray diffractometer (XRD) results indicated that well crystallized Sr-doped SnO 2 particles of size about 10 nm were obtained at sintering temperature 700℃. The optical properties viz. UV-Vis, FTIR and Raman were used to characterize various physico-chemical properties of samples. The reduction of grain size in metal oxide is a key factor to enhance the gas sensing properties. The doping of Sr in SnO 2 has reduced the grain size and improved the gas response. The results of gas sensing measurements showed that the thick films deposited on alumina substrates using screen-printing technique exhibited high gas response, quick response time and fast recovery time to acetone gas at a working temperature of 250℃. Further, the selectivity of sensor towards acetone with respect to other reducing gases (LPG, ethanol, ammonia) was studied. (author)

Growth and Properties of Oxygen and Ion Doped BISMUTH(2) STRONTIUM(2) Calcium COPPER(2) Oxygen (8+DELTA) Single Crystals

Science.gov (United States)

Mitzi, David Brian

1990-01-01

A directional solidification method for growing large single crystals in the Bi_2Sr _2CaCu_2O _{8+delta} system is reported. Ion substitutions, with replacement of La for Sr and Y for Ca, as well as oxygen doping in these crystals has been explored. Ion doping results in little change of the superconducting transition for substitution levels below 20-25% (as a result of simultaneous oxygen intercalation), while beyond this level, the Meissner signal broadens and the low temperature Meissner signal decreases. Microprobe analysis and x-ray diffraction performed on these more highly substituted single crystals, provides evidence for inhomogeneity and phase segregation into regions of distinct composition. Annealing unsubstituted crystals in increasing partial pressures of oxygen reversibly depresses the superconducting transition temperature from 90K (as made) to 77K (oxygen pressure annealed) while the Hall concentrations increase from n = 3.1(3) times 10 ^{21} cm^{ -3} (0.34 holes/Cu site) to 4.6(3) times 10^{21} cm^{-3} (0.50 holes/Cu site). Further suppression of T_{c} to 72K is possible by annealing in oxygen pressures up to 100atm. No degradation of the Meissner transition or other indications of inhomogeneity or phase segregation with doping are noted, suggesting that oxygen doped Bi_2Sr _2CaCu_2O _{8+delta} is a suitable system for pursuing doping studies. The decrease in T _{c} with concentration for 0.34 <=q n <=q 0.50 indicates that a high carrier concentration regime exists where T_{c} decreases with n and suggests that this decrease does not arise from material inhomogeneity or other materials problems. The physical properties of these Bi _2Sr_2CaCu _2O_{8+delta} crystals, in this high carrier concentration regime, will be discussed.

Bioactivity and corrosion properties of novel coatings containing strontium by micro-arc oxidation

Energy Technology Data Exchange (ETDEWEB)

Kung, Kuan-Chen [Department of Materials Science and Engineering, National Cheng Kung University, Tainan, Taiwan (China); Lee, Tzer-Min, E-mail: tmlee@mail.ncku.edu.t [Institute of Oral Medicine, National Cheng Kung University, Tainan, Taiwan (China); Lui, Truan-Sheng [Department of Materials Science and Engineering, National Cheng Kung University, Tainan, Taiwan (China)

2010-10-22

Research highlights: The dental implant of titanium could be modified by anodic oxidation. It was found that incorporation of strontium ions into the matrix increase the bone formation. In this study, we try to investigate the effect of corrosion property and bioactivity on coatings containing strontium by anodic oxidation. The results suggest that coatings containing strontium on titanium by anodic oxidation has the potential to show the stability and bioactivity in the clinical use. - Abstract: Pure titanium (Ti) and titanium alloys are considered as bio-inert materials in clinical use. Bioactivity is the ability to induce bone-like apatite on the material surface. The micro-arc oxidation (MAO) technique is an effective method for improving the surface properties of titanium. The aim of this study was to investigate the bioactivity and corrosion behavior of MAO coatings containing strontium, which is beneficial for biological performance. The bioactivity of materials was evaluated based on the ability to induce a bond-like apatite layer on the surface in simulated body fluid (SBF), as proposed by Kokubo et al. After the materials were soaked in SBF for 1 day, precipitates formed on the surface of MAO coating. The surface of MAO coatings was completely covered with precipitates after 7 days. The precipitates, which were found to be composed of fiber structures, were identified as the apatite phase using thin film X-ray diffraction (TF-XRD). The results show that MAO coatings containing strontium can induce the formation of an apatite layer on their surface. In the potentiodynamic test, MAO coatings exhibited a more noble corrosion potential (E{sub corr}) than that of titanium in SBF. In the passive region, the current density of MAO coatings was lower than that of titanium. All findings in this study indicated that MAO coatings containing strontium have good bioactivity and corrosion resistance for clinical applications.

Bioactivity and corrosion properties of novel coatings containing strontium by micro-arc oxidation

International Nuclear Information System (INIS)

Kung, Kuan-Chen; Lee, Tzer-Min; Lui, Truan-Sheng

2010-01-01

Research highlights: The dental implant of titanium could be modified by anodic oxidation. It was found that incorporation of strontium ions into the matrix increase the bone formation. In this study, we try to investigate the effect of corrosion property and bioactivity on coatings containing strontium by anodic oxidation. The results suggest that coatings containing strontium on titanium by anodic oxidation has the potential to show the stability and bioactivity in the clinical use. - Abstract: Pure titanium (Ti) and titanium alloys are considered as bio-inert materials in clinical use. Bioactivity is the ability to induce bone-like apatite on the material surface. The micro-arc oxidation (MAO) technique is an effective method for improving the surface properties of titanium. The aim of this study was to investigate the bioactivity and corrosion behavior of MAO coatings containing strontium, which is beneficial for biological performance. The bioactivity of materials was evaluated based on the ability to induce a bond-like apatite layer on the surface in simulated body fluid (SBF), as proposed by Kokubo et al. After the materials were soaked in SBF for 1 day, precipitates formed on the surface of MAO coating. The surface of MAO coatings was completely covered with precipitates after 7 days. The precipitates, which were found to be composed of fiber structures, were identified as the apatite phase using thin film X-ray diffraction (TF-XRD). The results show that MAO coatings containing strontium can induce the formation of an apatite layer on their surface. In the potentiodynamic test, MAO coatings exhibited a more noble corrosion potential (E corr ) than that of titanium in SBF. In the passive region, the current density of MAO coatings was lower than that of titanium. All findings in this study indicated that MAO coatings containing strontium have good bioactivity and corrosion resistance for clinical applications.

Non-Fickian dispersive transport of strontium in laboratory-scale columns: Modelling and evaluation

Science.gov (United States)

Liu, Dongxu; Jivkov, Andrey P.; Wang, Lichun; Si, Gaohua; Yu, Jing

2017-06-01

In the context of environmental remediation of contaminated sites and safety assessment of nuclear waste disposal in the near-surface zone, we investigate the leaching and non-Fickian dispersive migration with sorption of strontium (mocking strontium-90) through columns packed with sand and clay. Analysis is based on breakthrough curves (BTCs) from column experiments, which simulated rainfall infiltration and source term release scenario, rather than applying constant tracer solution at the inlet as commonly used. BTCs are re-evaluated and transport parameters are estimated by inverse modelling using two approaches: (1) equilibrium advection-dispersion equation (ADE); and (2) continuous time random walk (CTRW). Firstly, based on a method for calculating leach concentration, the inlet condition with an exponential decay input is identified. Secondly, the results show that approximately 39%-58% of Br- and 16%-49% of Sr2+ are eluted from the columns at the end of the breakthrough experiments. This suggests that trapping mechanisms, including diffusion into immobile zones and attachment of tracer on mineral surfaces, are more pronounced for Sr2+ than for Br-. Thirdly, we demonstrate robustness of CTRW-based truncated power-law (TPL) model in capturing non-Fickian reactive transport with 0 2. The non-Fickian dispersion observed experimentally is explained by variations of local flow field from preferential flow paths due to physical heterogeneities. Particularly, the additional sorption process of strontium on clay minerals contributes to the delay of the peak concentration and the tailing features, which leads to an enhanced non-Fickian transport for strontium. Finally, the ADE and CTRW approaches to environmental modelling are evaluated. It is shown that CTRW with a sorption term can describe non-Fickian dispersive transport of strontium at laboratory scale by identifying appropriate parameters, while the traditional ADE with a retardation factor fails to reproduce

Full-Scale and Bench-Scale Studies on the Removal of Strontium from Water (abstract)

Science.gov (United States)

Strontium (Sr) is a natural and commonly occurring alkaline earth metal which has an oxidation state of +2 under normal environmental conditions. Stable strontium is suspended in water and is dissolved after water runs through rocks and soil. It behaves very similar to calcium. G...

Simplified method for the determination of strontium-90 in large amounts of bone-ash

International Nuclear Information System (INIS)

Patti, F.; Jeanmaire, L.

1966-06-01

The principle of the determination is based on a 3-step process: 1) concentrating the strontium by attacking the ash with nitric acid; 2) elimination of residual phosphoric ions by a double precipitation of strontium oxalate; and 3) extraction of yttrium 90, counted in the oxalate form. The advantages of the method: -) using simple techniques it makes it possible to process 50 g of ash; -) the initial concentration of strontium considerably reduces the volume of the solutions as well as the size of precipitates handled. Fuming nitric acid is used in a specially designed burette. (authors) [fr

Physical barrier effect of geopolymeric waste form on diffusivity of cesium and strontium.

Science.gov (United States)

Jang, J G; Park, S M; Lee, H K

2016-11-15

The present study investigates the physical barrier effect of geopolymeric waste form on leaching behavior of cesium and strontium. Fly ash-based geopolymers and slag-blended geopolymers were used as solidification agents. The leaching behavior of cesium and strontium from geopolymers was evaluated in accordance with ANSI/ANS-16.1. The diffusivity of cesium and strontium in a fly ash-based geopolymer was lower than that in Portland cement by a factor of 10(3) and 10(4), respectively, showing significantly improved immobilization performance. The leaching resistance of fly ash-based geopolymer was relatively constant regardless of the type of fly ash. The diffusivity of water-soluble cesium and strontium ions were highly correlated with the critical pore diameter of the binder. The critical pore diameter of the fly ash-based geopolymer was remarkably smaller than those of Portland cement and slag-blended geopolymer; consequently, its ability physically to retard the diffusion of nuclides (physical barrier effect) was superior. Copyright © 2016 Elsevier B.V. All rights reserved.

Strontium distribution and origins in a natural clayey formation (Callovian-Oxfordian, Paris Basin, France): a new sequential extraction procedure

International Nuclear Information System (INIS)

Lerouge, C.; Gaucher, E.C.; Tournassat, C.; Negrel, P.; Crouzet, C.; Guerrot, C.; Gautier, A.; Michel, P.; Vinsot, A.; Buschaert, S.

2010-01-01

Document available in extended abstract form only. Strontium is a minor element in the Callovian-Oxfordian clayey formation of Bure (ANDRA Underground Research laboratory, France) and may be interesting as a natural analogue of cationic radionuclides. The objective of our study was to better understand the chemical behaviour of this element since the sediment deposition. Previous mineralogical work showed that main strontium-bearing minerals in the clay-stones, in addition to clay minerals, are celestite, carbonates and accessory micas and K-feldspars. In order to establish the strontium distribution and determine its origins across the clayey formation and establish a strontium diffusion profile, a four step sequential extraction procedure combined with strontium isotopes was developed and adapted to the mineralogy of the Bure clay-stones. The four-steps sequential extraction developed and applied to sixteen samples of Callovian-Oxfordian clay-stones showed that the exchangeable fraction (27 to 48% of the total strontium) and the carbonate fraction (38-47% of the total strontium) are the two main fractions carrying the strontium, the detrital fraction being secondary (< 15%). Celestite is the major strontium-carrier mineral that can perturb the results of the sequential extraction but not significantly modify the distribution of strontium at the scale of the formation. The celestite was studied on micronic to centi-metric crystals, separated by hand-picking on core samples. The development of this sequential extraction procedure for the Callovian-Oxfordian formation shows the importance of the first cobalt hexamine trichloride step to extract the exchangeable strontium adsorbed on clay minerals and block the exchangeable sites with cobalt for the following steps, allowing a good separation of exchangeable fraction and carbonates. However the reagent/solid ratio of 20 seems to be less adapted to carbonate-rich samples. The good separation between exchangeable

Influence of La doping on structural and dielectric properties of SrBi2Nb2O9 ceramics

Science.gov (United States)

Verma, Maya; Sreenivas, K.; Gupta, Vinay

2009-01-01

Lanthanum doped SrBi2Nb2O9 ceramics with the chemical formula SrBi2-xLaxNb2O9 (SBLN) (x =0-0.5) have been prepared through conventional solid state route. X-ray diffraction reveals the shrinkage of unit cell of strontium bismuth niobate with incorporation of La3+ dopant, having no lone pair electrons. Shifting of Raman phonon modes indicates the reduced rattling space of NbO6 octahedra with increase in La doping concentration. Further, the softening of lowest frequency phonon mode with increasing x in SBLN shows the transition from ferroelectric to paraelectric at room temperature. The dielectric properties for all the compositions are studied as a function of temperature (25 to 500 °C) over the frequency range of 10 kHz-1 MHz. With increase in lanthanum doping concentration the phase transition becomes diffused and transition temperature gets shifted toward lower temperature. A phase transition from normal ferroelectric to paraelectric has been observed via relaxor-type ferroelectrics with increase in x. The frequency dependence of transition temperature was studied in terms of Vogel-Fulcher relation for SBLN (x =0.4).

Influence of La doping on structural and dielectric properties of SrBi2Nb2O9 ceramics

International Nuclear Information System (INIS)

Verma, Maya; Sreenivas, K.; Gupta, Vinay

2009-01-01

Lanthanum doped SrBi 2 Nb 2 O 9 ceramics with the chemical formula SrBi 2-x La x Nb 2 O 9 (SBLN) (x=0-0.5) have been prepared through conventional solid state route. X-ray diffraction reveals the shrinkage of unit cell of strontium bismuth niobate with incorporation of La 3+ dopant, having no lone pair electrons. Shifting of Raman phonon modes indicates the reduced rattling space of NbO 6 octahedra with increase in La doping concentration. Further, the softening of lowest frequency phonon mode with increasing x in SBLN shows the transition from ferroelectric to paraelectric at room temperature. The dielectric properties for all the compositions are studied as a function of temperature (25 to 500 deg. C) over the frequency range of 10 kHz-1 MHz. With increase in lanthanum doping concentration the phase transition becomes diffused and transition temperature gets shifted toward lower temperature. A phase transition from normal ferroelectric to paraelectric has been observed via relaxor-type ferroelectrics with increase in x. The frequency dependence of transition temperature was studied in terms of Vogel-Fulcher relation for SBLN (x=0.4)

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

International Nuclear Information System (INIS)

Kanagesan, S.; Jesurani, S.; Velmurugan, R.; Prabu, S.; Kalaivani, T.

2012-01-01

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 B 0.5 Sr 0.5 Fe 12−2x Ni x Zr x O 19 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 H c decreases remarkably with increasing Ni and Zr ions content. It was found that the particle size could be effectively decreased and coercivity H c could easily be controlled by varying the concentration (x) without significantly decreasing saturation magnetization. In particular, Ba 0.5 Sr 0.5 Fe 12−2x Ni x Zr x O 19 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.

Ecology of Acantharia and Strontium Circulation in the Sea; Ecologie des Acanthaires et Circulation du Strontium en Mer; 0411 0414 ; Ecologia de los Acantarios y Circulacion del Estroncio en el Mar

Energy Technology Data Exchange (ETDEWEB)

Schreiber, Bruno [Department of Zoology, University of Parma (Italy)

1960-07-01

The author first considers the biochemical cycle of strontium in sea-water and then examines the proposed programme and the objectives it is hoped to achieve. The Acantharia group was selected for this study since it is the only one which has a specific and exclusive deposit of strontium. It is, therefore, of particular interest in relation to the problems concerning the circulation of strontium and radioactive isotopes resulting from fall-out. (author) [French] L'auteur procede d'abord a une etude du cycle bio-chimique du strontium dans l'eau de mer, puis il procede a l'etude du programme envisage et des objectifs poursuivis. Les Acanthaires ont ete choisis pour cette etude car ils constituent le seul groupe possedant un depot de strontium specifique et exclusif. Il est donc particulierement interessant een ce qui concerne les problemes relatifs a la circulation du strontium et des isotopes radioactifs provenant des retombees. (author) [Spanish] El autor estudia primero el ciclo bioquimico del estroncio en las aguas del mar, y procede luego al estudio del programa proyectado y de los objetivos perseguidos. Para realizar este estudio se ha escogido a los acantarios porque su esqueleto contiene estroncio. Por ello, este grupo es de especial interes en lo que respecta a los problemas de la circulacion del estroncio y de los radioisotopos procedentes de las precipitaciones radiactivas. (author) [Russian] Prezhde vsego avtor opisyvaet biohimicheskij cikl stroncija v morskoj vode, a zatem perehodit k rassmotreniju planiruemoj programmy i presleduemyh celej. Dlja jetogo issledovanija byla vybrana akantarija (Acantharia), tak kak ona javljaetsja edinstvennoj gruppoj, imejushhej specificheskie i edinstvennye v svoem rode otlozhenija stroncija. Takim obrazom, ona javljaetsja krajne interesnoj v otnoshenii problem, svjazannyh s cirkuljaciej stroncija i radioaktivnyh izotopov, poluchaemyh v rezul'tate vypadenija osadkov. (author)

Osteogenic differentiation of stem cells from human exfoliated deciduous teeth on poly(ε-caprolactone) nanofibers containing strontium phosphate

Energy Technology Data Exchange (ETDEWEB)

Su, Wen-Ta, E-mail: f10549@ntut.edu.tw [Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taipei, Taiwan (China); Wu, Pai-Shuen [Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, Taipei, Taiwan (China); Huang, Te-Yang [Department of Orthopedic Surgery, Mackay Memorial Hospital, Taipei, Taiwan (China)

2015-01-01

Mimicking the architecture of the extracellular matrix is an effective strategy for tissue engineering. Composite nanofibers similar to natural bone structure can be prepared via an electrospinning technique and used in biomedical applications. Stem cells from human exfoliated deciduous teeth (SHEDs) can differentiate into multiple cell lineages, such as cells that are alternative sources of stem cells for tissue engineering. Strontium has important functions in bone remodeling; for example, this element can simulate bone formation and decrease bone resorption. Incorporating strontium phosphate into nanofibers provides a potential material for bone tissue engineering. This study investigated the potential of poly(ε-caprolactone) (PCL) nanofibers coated or blended with strontium phosphate for the osteogenic differentiation of SHEDs. Cellular morphology and MTT assay revealed that nanofibers effectively support cellular attachment, spreading, and proliferation. Strontium-loaded PCL nanofibers exhibited higher expressions of collagen type I, alkaline phosphatase, biomineralization, and bone-related genes than pure PCL nanofibers during the osteogenic differentiation of SHEDs. This study demonstrated that strontium can be an effective inducer of osteogenesis for SHEDs. Understanding the function of bioceramics (such as strontium) is useful in designing and developing strategies for bone tissue engineering. - Highlights: • SHEDs have been considered as alternative sources of adult stem cells in tissue engineering. • Strontium phosphate into nanofibers provides a potential material for bone tissue engineering. • Nanofibers coated or blended with strontium phosphate for the osteogenic differentiation of SHEDs.

Osteogenic differentiation of stem cells from human exfoliated deciduous teeth on poly(ε-caprolactone) nanofibers containing strontium phosphate

International Nuclear Information System (INIS)

Su, Wen-Ta; Wu, Pai-Shuen; Huang, Te-Yang

2015-01-01

Mimicking the architecture of the extracellular matrix is an effective strategy for tissue engineering. Composite nanofibers similar to natural bone structure can be prepared via an electrospinning technique and used in biomedical applications. Stem cells from human exfoliated deciduous teeth (SHEDs) can differentiate into multiple cell lineages, such as cells that are alternative sources of stem cells for tissue engineering. Strontium has important functions in bone remodeling; for example, this element can simulate bone formation and decrease bone resorption. Incorporating strontium phosphate into nanofibers provides a potential material for bone tissue engineering. This study investigated the potential of poly(ε-caprolactone) (PCL) nanofibers coated or blended with strontium phosphate for the osteogenic differentiation of SHEDs. Cellular morphology and MTT assay revealed that nanofibers effectively support cellular attachment, spreading, and proliferation. Strontium-loaded PCL nanofibers exhibited higher expressions of collagen type I, alkaline phosphatase, biomineralization, and bone-related genes than pure PCL nanofibers during the osteogenic differentiation of SHEDs. This study demonstrated that strontium can be an effective inducer of osteogenesis for SHEDs. Understanding the function of bioceramics (such as strontium) is useful in designing and developing strategies for bone tissue engineering. - Highlights: • SHEDs have been considered as alternative sources of adult stem cells in tissue engineering. • Strontium phosphate into nanofibers provides a potential material for bone tissue engineering. • Nanofibers coated or blended with strontium phosphate for the osteogenic differentiation of SHEDs

Strontium ranelate in the treatment of osteoporosis

African Journals Online (AJOL)

2006-11-05

Nov 5, 2006 ... postmenopausal women (mean age 69 years) with osteoporosis or osteopenia. Strontium ranelate significantly decreased markers of bone resorption and increased biomarkers of formation. Spinal BMD increased by 14%, while vertebral fractures decreased by 49% within the first year, a reduction that was.

Ecological Dose Modeling of Aquatic and Riparian Receptors to Strontium-90 with an Emphasis on Radiosensitive Organs

Energy Technology Data Exchange (ETDEWEB)

Poston, Ted M.; Traub, Richard J.; Antonio, Ernest J.

2011-07-20

The 100-NR-2 site is the location of elevated releases of strontium-90 to the Columbia River via contaminated groundwater. The resulting dose to aquatic and riparian receptors was evaluated in 2005 (DOE 2009) and compared to U.S. Department of Energy (DOE) dose guidance values. We have conducted additional dose assessments for a broader spectrum of aquatic and riparian organisms using RESRAD Biota and specific exposure scenarios. Because strontium-90 accumulates in bone, we have also modeled the dose to the anterior kidney, a blood-forming and immune system organ that lies close to the spinal column of fish. The resulting dose is primarily attributable to the yttrium-90 progeny of strontium-90 and very little of the dose is associated with the beta emission from strontium-90. All dose modeling results were calculated with an assumption of secular equilibrium between strontium-90 and yttrum-90.

Development of an Age- and Gender-specific Model for Strontium Metabolism in Humans

International Nuclear Information System (INIS)

Shagina, N. B.; Degteva, M. O.; Tolstykh, E. I.

2004-01-01

This paper presents a development of a new biokinetic model for strontium, which accounts for age and gender differences of metabolism in humans. This model was developed based on the long-term follow-up of the residents living on the banks of the Techa River (Southern Urals, Russia) contaminated with 89,90Sr in 1950-1956. The new model uses the structure of ICRP model for strontium but model parameters have been estimated to account for age, gender and population differences in strontium retention and elimination. Estimates of age- and gender-specific model parameters were derived from (a) the results of long-term measurements of 90Sr-body burden for the Techa River population; (b) experimental studies of calcium and strontium metabolism in humans and (c) non-radiological data regarding bone metabolism (mineral content of the body, bone turnover, etc). As a result, the new model satisfactorily describes data on long-term retention of 90Sr in residents of the Techa River settlements of all ages and both genders and also data from studies during the period of global fallout in the UK and the USA and experimental data on strontium retention in humans. The new model can be used to calculate dose from 89,90Sr for the Techa River residents and also for other populations with similar parameters of skeletal maturation and also for other populations with similar parameters of skeletal maturation and involution. (Author) 27 refs

Competition effect of some metal ions on the complexation of strontium with humic acid. Vol. 4

Energy Technology Data Exchange (ETDEWEB)

Helal, A A; Aly, H F; Imam, D M; Khalifa, S M [Atomic Energy Authorty, Cairo (Egypt)

1996-03-01

Interaction of radioactive strontium with humic acid present in water streams is of main importance to learn about the fate of strontium in case of accidental release. In this work, formation of Sr-humate precipitate was studied radiometrically and colorimetric at different PH`s. The investigations indicated that formation of the precipitated complex increases with increasing strontium concentration till saturation. The competition effect of other cations in solution such as Ca, Mg, Ba, and Ni was investigated. The humate complexes of these cations were studied colorimetric, and the competition behaviour was investigated using the radiotracer of strontium. The results indicated that presence of Ba, Mg and Ni decreases the Sr-humate complex, while increasing Ca concentration enhances precipitation of Sr with humic acid. 10 figs.

Forecast of strontium 90 accumulation in the crop of agricultural cultures

International Nuclear Information System (INIS)

Dergunov, I.D.; Moroz, V.D.

1980-01-01

A possibility to determine the level of contamination with strontium-90 of agricultural crops according to its content in young plants as studied. The investigations have been carried out under conditions of vegetational experiment with cotton on light, typical, dark grey soils and meadow spoils. The samples in the phase of 20 day old plants and in the period of ripening have been selected for radiometric analysis. Activity has been measured according to β-irradiation of nuclide. Tbe measurement results point to the existence of certain connection between radiostrontium content in young plants and in the fibre crops. Close connection is also found between strontium-90 content in young plants and in the cotton seeds. Direct proportional dependence between strontium-90 content in young and grown-up plants is established. Linear coefficients for cotton are obtained which can be used for forecasting the level of cotton fibre contamination with radiostrontium according to its content in 20 day old plants

Adsorption of strontium (II) metal ions using phosphonate ...

Indian Academy of Sciences (India)

Chelation is a process wherein metalions and a polymer/matrix are bound together ... waste: evaporation, chemical precipitation/flocculation, solid-phase separation ... sary to remove strontium from the waste streams before it is discharged to ...

Strontium isotopes as an indicator for groundwater salinity sources in the Kirkuk region, Iraq

Energy Technology Data Exchange (ETDEWEB)

Sahib, Layth Y. [Institute for Applied Geosciences, Technische Universität Darmstadt, Schnittspahnstraße 9, 64287 Darmstadt (Germany); Geology Department, College of Science, University of Baghdad, Jadreya, Baghdad (Iraq); Marandi, Andres; Schüth, Christoph [Institute for Applied Geosciences, Technische Universität Darmstadt, Schnittspahnstraße 9, 64287 Darmstadt (Germany)

2016-08-15

The Kirkuk region in northern Iraq hosts some of the largest oil fields in the Middle East. Several anticline structures enabled vertical migration and entrapment of the oil. Frequently, complex fracture systems and faults cut across the Eocene and middle Oligocene reservoirs and the cap rock, the Fatha Formation of Miocene age. Seepage of crude oil and oil field brines are therefore a common observation in the anticline axes and contamination of shallow groundwater resources is a major concern. In this study, 65 water samples were collected in the Kirkuk region to analyze and distinguish mixing processes between shallow groundwater resources, uprising oil field brines, and dissolution of gypsum and halite from the Fatha Formation. Hydrochemical analyses of the water samples included general hydrochemistry, stable water isotopes, as well as strontium concentrations and for 22 of the samples strontium isotopes ({sup 87}Sr/{sup 86}Sr). Strontium concentrations increased close to the anticline axes with highest concentrations in the oil field brines (300 mg/l). Strontium isotopes proved to be a valuable tool to distinguish mixing processes as isotope signatures of the oil field brines and of waters from the Fatha Formation are significantly different. It could be shown, that mixing of shallow groundwater with oil field brines is occurring close to the major fault zones in the anticlines but high concentrations of strontium in the water samples are mainly due to dissolution from the Fatha Formation. - Highlights: • This field study evaluates the salinity sources in the groundwater in Kirkuk region. • Salinity is related to evaporates dissolving and/or mixing with oil field brine. • Strontium isotopes proved to be a valuable tool to distinguish mixing processes.

A new method of accurate determination of isotopic composition and concentration of strontium in a spike solution used for geochronological works

International Nuclear Information System (INIS)

Yanagi, Takeru

1990-01-01

A new method of accurate determination of isotopic composition and concentration of a strontium-84 spike solution was devised for simultaneous determination of strontium contents and isotopic compositions in rocks and minerals by measuring strontium isotopic ratios in spiked samples. In this method, the isotopic composition of strontium in the spike were determined so as to minimize the sum of squares of deviations of spike strontium-84 concentrations which were calculated from measured isotopic ratios of strontium in five different mixtures of the spike and the standard solution. The method can eliminate all mass discriminations occurred during the measurements on a surface ionization mass spectrometer. The results were tested by measuring 87 Sr/ 86 Sr ratios of Eimer and Amend SrCO 3 and JB-1 geochemical reference material, and by determining the strontium content in JB-1. The measurements of strontium isotope ratios in spiked samples give average values of 0.708007±0.000052 and 0.70417±0.00004 for 87 Sr/ 86 Sr ratios of E and A SrCO 3 and JB-1, respectively. The strontium content in JB-1 was estimated at 457.1±1.3 ppm. These values are very close to reported respective values. (author)

Characterization of crystallite morphology for doped strontium fluoride nanophosphors by TEM and XRD

Energy Technology Data Exchange (ETDEWEB)

O' Connell, J.H. [Centre for HRTEM, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth ZA6031 (South Africa); Lee, M.E., E-mail: Michael.lee@nmmu.ac.za [Centre for HRTEM, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth ZA6031 (South Africa); Yagoub, M.Y.A.; Swart, H.C.; Coetsee, E. [Department of Physics, University of the Free State, PO Box 339, Bloemfontein ZA9300 (South Africa)

2016-01-01

Crystallite morphology for Eu-doped and undoped SrF{sub 2} nanophosphors have been determined by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The values for average crystallite size obtained by the application of the Scherrer equation and the full width at half maximum (FWHM) values for XRD peaks are compared to the results obtained using the hollow cone dark field (HCDF) TEM imaging technique. In the case of the TEM analysis, a bimodal crystallite size distribution was revealed with one of the distributions having a measured range of crystallite sizes which was in good agreement with the XRD data. HCDF in combination with FIB specimen preparation was found to be a promising technique for the determination of crystallite size distributions in nanophosphors which might facilitate a better understanding of their scintillation properties.

Characterization of crystallite morphology for doped strontium fluoride nanophosphors by TEM and XRD

International Nuclear Information System (INIS)

O'Connell, J.H.; Lee, M.E.; Yagoub, M.Y.A.; Swart, H.C.; Coetsee, E.

2016-01-01

Crystallite morphology for Eu-doped and undoped SrF_2 nanophosphors have been determined by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The values for average crystallite size obtained by the application of the Scherrer equation and the full width at half maximum (FWHM) values for XRD peaks are compared to the results obtained using the hollow cone dark field (HCDF) TEM imaging technique. In the case of the TEM analysis, a bimodal crystallite size distribution was revealed with one of the distributions having a measured range of crystallite sizes which was in good agreement with the XRD data. HCDF in combination with FIB specimen preparation was found to be a promising technique for the determination of crystallite size distributions in nanophosphors which might facilitate a better understanding of their scintillation properties.

Magnetic CuHCNPAN nano composite as an efficient adsorbent for strontium uptake

Science.gov (United States)

Mobtaker, Hossein Ghasemi; Pakzad, Seyed Mohammadreza; Yousefi, Taher

2018-06-01

An excellent composite was synthesized for sorption of strontium from solution. The composite (CuHCNPAN) components were copper hexacyanoferrate, magnetite and PAN. The XRD method confirmed the formation and presence of two crystalline phases of magnetite and copper hexacyanoferrate in composite. Particle sizes were determined by XRD and SEM methods. It was found that the particles were nano size. Some other methods such as FT IR, BET and TG methods were also used to determine the properties of the composite. The composite was used for sorption of strontium from solution. It was found that the kinetic of strontium sorption by the composite could be modeled by pseudo-second order. Among the isotherms applied to modeling the sorption in various concentrations, the Langmuir isotherm was founded to be more appropriate to fitting the experimental data. An excellent correlation coefficient was obtained (R2 > 0.98). The qmax for sorption of strontium ions which was calculated by Langmuir model was 80 mg/g. The thermodynamic parameters were calculated by determination of sorption in various temperatures and using the Vant Hoff plot. ΔG°, ΔH°, and ΔS° were calculated as -19.15, 2.28 and 0.071 kJ/mol respectively.

Study of mineral ion exchangers for strontium removal from nuclear waste waters

International Nuclear Information System (INIS)

Merceille, A.

2012-01-01

The problems of chemical pollution of water have become a major concern and a priority for the nuclear industry. The aim of this work is to study some ion exchangers used for the removal of strontium ions because 90 Sr is one of a major pollutant in nuclear liquid wastes. This study allows linking the physical and chemical properties of these materials and their sorption properties. This work presents therefore the synthesis of two materials - sodium nona-titanate and zeolite A - selected for their specific sorption properties of strontium: A second part of this work is dedicated to the study of specific exchange capacities of these materials for the strontium in presence of other elements such as sodium and calcium. Batch experiments were performed and kinetic and ion exchange models have been applied to understand the selectivity of the materials for strontium removal. Sodium nona-titanate and zeolite A are also studied in actual effluents. Monoliths of zeolite A have been also tested in dynamic ion exchange process. This material is promising for the treatment of radioactive effluents in continuous flow because it joins the sorption properties of the zeolite powder with the advantage of a solid with a macroporous network. (author) [fr

Osteoblastic differentiation of stem cells from human exfoliated deciduous teeth induced by thermosensitive hydrogels with strontium phosphate

Energy Technology Data Exchange (ETDEWEB)

Su, Wen-Ta, E-mail: f10549@ntut.edu.tw [Department of Chemical Engineering and Biotechnology National Taipei University of Technology, Taipei, Taiwan (China); Chou, Wei-Ling [Department of Chemical Engineering and Biotechnology National Taipei University of Technology, Taipei, Taiwan (China); Chou, Chih-Ming [Department of Biochemistry, Taipei Medical University, Taipei, Taiwan (China)

2015-07-01

Stem cells from human exfoliated deciduous teeth (SHEDs) are a novel source of multi-potential stem cells for tissue engineering because of their potential to differentiate into multiple cell lineages. Strontium exhibits an important function in bone remodeling because it can simulate bone formation and decrease bone resorption. Hydrogels can mimic the natural cellular environment. The association of hydrogels with cell viability is determined using biological tests, including rheological experiments. In this study, osteogenic differentiation was investigated through SHED encapsulation in hydrogels containing strontium phosphate. Results of 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and proliferating cell nuclear antigen (PCNA) immunofluorescence staining indicated that the cells grew well and SHEDs proliferated in the hydrogels. Strontium-loaded chitosan-based hydrogels induced the biomineralization and high expression of alkaline phosphatase. Moreover, the expression levels of bone-related genes, including type-I collagen, Runx2, osteopontin (OP), and osteonectin (ON), were up-regulated during the osteogenic differentiation of SHEDs. This study demonstrated that strontium can be an effective inducer of osteogenesis for SHEDs. Elucidating the function of bioceramics (such as strontium) is useful in designing and developing strategies for bone tissue engineering. - Highlights: • SHEDs have been considered as alternative sources of adult stem cells in tissue engineering. • Strontium phosphate can enhance the osteogenic differentiation of SHEDs. • Hydrogels can mimic the natural cellular environment. • Bioceramics (such as strontium) is useful in designing and developing strategies for bone tissue engineering.

Assessment of strontium in the Savannah River Site environment

International Nuclear Information System (INIS)

Carlton, W.H.; Evans, A.G.; Geary, L.A.; Murphy, C.E. Jr.; Strom, R.N.

1992-01-01

This document on strontium is published as a part of the Radiological Assessment Program (RAP). It is the sixth in a series of eight documents on individual radioisotopes released to the environment as a result of SRS (Savannah River Site) operations. Strontium exists in the environment as a result of above-ground nuclear weapons tests, the Chernobyl accident, the destruction of satellite Cosmos 954, small releases from reactors and reprocessing plants, and the operation of industrial, medical, and educational facilities. Strontium has been produced at SRS during the operation of 5 production reactors. About 300 curies of radiostrontium were released into streams in the late 50s and 60s, primarily from leaking fuel elements in reactor storage basins. Smaller quantities were released from the fuel reprocessing operations. About 400 Ci were released to seepage basins. A much smaller quantity, about 2 Ci, was released to the atmosphere. The overall radiological impact of SRS releases on the offsite maximum individual can be characterized by total doses of 6.2 mrem (atmospheric) and 1.4 mrem (liquid), compared with a dose of 12,960 mrem from non-SRS sources during the same period of time. Radiostrontium releases have resulted in a negligible risk to the environment and the population it supports

Assessment of strontium in the Savannah River Site environment

Energy Technology Data Exchange (ETDEWEB)

Carlton, W.H.; Evans, A.G.; Geary, L.A.; Murphy, C.E. Jr.; Strom, R.N.

1992-12-31

This document on strontium is published as a part of the Radiological Assessment Program (RAP). It is the sixth in a series of eight documents on individual radioisotopes released to the environment as a result of SRS (Savannah River Site) operations. Strontium exists in the environment as a result of above-ground nuclear weapons tests, the Chernobyl accident, the destruction of satellite Cosmos 954, small releases from reactors and reprocessing plants, and the operation of industrial, medical, and educational facilities. Strontium has been produced at SRS during the operation of 5 production reactors. About 300 curies of radiostrontium were released into streams in the late 50s and 60s, primarily from leaking fuel elements in reactor storage basins. Smaller quantities were released from the fuel reprocessing operations. About 400 Ci were released to seepage basins. A much smaller quantity, about 2 Ci, was released to the atmosphere. The overall radiological impact of SRS releases on the offsite maximum individual can be characterized by total doses of 6.2 mrem (atmospheric) and 1.4 mrem (liquid), compared with a dose of 12,960 mrem from non-SRS sources during the same period of time. Radiostrontium releases have resulted in a negligible risk to the environment and the population it supports.

Strontium-90 and cesium-137 in soil from May 1984 to July 1984

International Nuclear Information System (INIS)

1984-01-01

Strontium-90 and cesium-137 in soil measured throughout Japan from May to July 1984 are given in pCi/kg and mCi/km 2 . Sampling points are total of 8 from Kawabe-gun (Akita) to Ibasuki-gun (Kagoshima). Collection and pretreatment of samples, preparation of samples for analysis, separation of strontium-90 and cesium-137, determination of stable strontium, calcium and potassium, and counting are described. Soil was collected from the location in the spacious and flat area without past disturbance on the surface. Soil was taken from two layers of different depths, 0 aproximately 5 cm and 5 approximately 20 cm. After the radiochemical separation, the mounted precipitates were counted for activity using low background beta counters normally for 60 minutes. (Mori, K.)

Evaluation of a cell-biopolymer sorbent for uptake of strontium from dilute solutions

International Nuclear Information System (INIS)

Watson, J.S.; Scott, C.D.; Faison, B.D.

1990-01-01

Immobilization of Micrococcus luteus within beads of bone gelatin results in a material which is able to adsorb significant quantities of strontium from dilute aqueous solutions analogous to some nuclear industry wastewaters. The mechanism appears to be principally an ion-exchange phenomenon. Both the bone gelatin and the microbial cells contribute to strontium removal; the principal contribution from the cells appears to be sorption onto cell wall material. This particular biosorbent may not be an immediate replacement for conventional ion-exchange materials currently used to remove strontium from wastewaters. However, the study does indicate that relatively inexpensive biological materials can be incorporated into particulate forms such as gel beads and used for the removal of dissolved metal ions from aqueous solution

Optimization of a Strontium Aluminate

Energy Technology Data Exchange (ETDEWEB)

Bone, Alexandria N. [Maryville College, TN (United States)

2017-08-01

Strontium aluminate with Eu²⁺ and Dy³⁺ has been at the forefront of emerging applications for storage phosphors since its discovery in 1996. In this study, the emission intensity and luminescence lifetime of SrAl₂O₄: Eu²⁺, Dy³⁺ were enhanced by partial substitution of Ca²⁺ into Sr²⁺ sites in the matrix.

Strontium isotope stratigraphy of the Pelotas Basin

Energy Technology Data Exchange (ETDEWEB)

Zerfass, Geise de Santana dos Anjos, E-mail: geise.zerfass@petrobras.com.br [Petroleo Brasileiro S.A. (PETROBRAS/CENPES/PDGEO/BPA), Rio de Janeiro, RJ (Brazil). Centro de Pesquisas e Desenvolvimento Leopoldo Americo Miguez de Mello; Chemale Junior, Farid, E-mail: fchemale@unb.br [Universidade de Brasilia (UnB), DF (Brazil). Instituto de Geociencias; Moura, Candido Augusto Veloso, E-mail: candido@ufpa.br [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Centro de Geociencias. Dept. de Geoquimica e Petrologia; Costa, Karen Badaraco, E-mail: karen.costa@usp.br [Instituto Oceanografico, Sao Paulo, SP (Brazil); Kawashita, Koji, E-mail: koji@usp.br [Unversidade de Sao Paulo (USP), SP (Brazil). Centro de Pesquisas Geocronologicas

2014-07-01

Strontium isotope data were obtained from foraminifera shells of the Pelotas Basin Tertiary deposits to facilitate the refinement of the chronostratigraphic framework of this section. This represents the first approach to the acquisition of numerical ages for these strata. Strontium isotope stratigraphy allowed the identification of eight depositional hiatuses in the Eocene-Pliocene section, here classified as disconformities and a condensed section. The reconnaissance of depositional gaps based on confident age assignments represents an important advance considering the remarkably low chronostratigraphic resolution in the Cenozoic section of the Pelotas Basin. The recognition of hiatuses that match hiatuses is based on biostratigraphic data, as well as on global events. Furthermore, a substantial increase in the sedimentation rate of the upper Miocene section was identified. Paleotemperature and productivity trends were identified based on oxygen and carbon isotope data from the Oligocene-Miocene section, which are coherent with worldwide events, indicating the environmental conditions during sedimentation. (author)

An optimization on strontium separation model for fission products (inactive trace elements) using artificial neural networks

International Nuclear Information System (INIS)

Moosavi, K.; Setayeshi, S.; Maragheh, M.Gh.; Ahmadi, S.J.; Kardan, M.R.; Banaem, L.M.

2009-01-01

In this study, an experimental design using artificial neural networks for an optimization on the strontium separation model for fission products (inactive trace elements) is investigated. The goal is to optimize the separation parameters to achieve maximum amount of strontium that is separated from the fission products. The result of the optimization method causes a proper purity of Strontium-89 that was separated from the fission products. It is also shown that ANN may be establish a method to optimize the separation model.

Hydrogen content, interfacial exchange and hydrogen diffusion in high-temperature protonic conductors based on strontium and barium cerates

International Nuclear Information System (INIS)

Vdovin, G.K.; Kurumchin, Eh.Kh.

2004-01-01

The hydrogen content and kinetics of the hydrogen exchange in the barium and strontium doped cerates are studied in the reduction atmosphere through the methods of isotope counterbalancing and isotope exchange. The measurements are carried out at 500-840 Deg C and hydrogen pressure of 2.7-16 gPa. It is established, that the hydrogen interfacial exchange proceeds at high velocities through the dissociative-type mechanisms. The effective activation energy of the hydrogen heteroexchange is determined. The coefficient of the hydrogen diffusion in BaCe 0.95 Nd 0.5 O 3-δ is calculated. The hydrogen content per formula unit constituted (0.48±0.05) in the SrCe 0.95 Y 0.05 O 3-δ and (0.60±0.05) in the BaCe 0.95 Nd 0.5 O 3-δ at 550 and 720 Deg C correspondingly and hydrogen pressure of 6.7 gPa [ru

A distribution of adsorbed forms of cesium 137 and strontium 90 in flood-plain formations of Sozh river

International Nuclear Information System (INIS)

Kuznetsov, V.A.; Generalova, V.A.

1999-01-01

The distribution of strontium 90 and cesium 137 forms in flood-plain geochemical system 'alluvial deposits - flood-plain turf - humus horizon - soil-source rock', where sorption and colloidal processes play main role in the isotopes migration, was studied. The bulk amount of strontium 90 is presented in adsorbed form in all investigated objects, whereas only 6% of cesium 137 amount in alluvial deposits, flood-plain turf and humus horizon is in adsorbed form. The content of exchange forms of cesium 137 and strontium 90 increases with the depth of the layer. The race of this increase for strontium 90 is large than for cesium 137. The distribution of radionuclides through the different parts of flood-plain of Sozh river has some distinctions due to more lability of adsorbed strontium 90 forms in comparison with cesium 137 ones

Permanganate Treatment of Savannah River Site Simulant Wastes for Strontium and Actinide Removal

International Nuclear Information System (INIS)

Wilmarth, W.R.

2003-01-01

This study examined the use of sodium permanganate and strontium nitrate to remove the actinides and radio-strontium from Savannah River Site (SRS) waste supernate. We examined the quantities of chemical feed reagents along with increased mixing and the excess of organic reductant. Additionally, we examined two processing schemes including that applicable to either the Salt Waste Processing Facility or the Alpha Removal Process (ARP) (5.6 M sodium ion concentration) conditions and the conditions for an In-Tank application (7.5 M sodium ion concentration). Our results support the following conclusions: The process met minimum required decontamination factors (DFs) within the tested parameter sets for strontium and plutonium in both the ARP and In-Tank application. The strontium DFs far exceeded the required values within the tested parameter sets. Within the ARP application, the use of peroxide as the reductant for permanganate produced higher plutonium DFs than the use of sodium formate. Reductant concentration and degree of mixing strongly influenced radionuclide decontamination. In the formate application under the ARP process, increasing the reductant concentration and mixing energy resulted in higher Sr and Pu decontamination

Strontium-90 and cesium-137 in soil (from May, 1982, to September, 1982)

International Nuclear Information System (INIS)

1982-01-01

Strontium-90 and cesium-137 in soil measured at 29 locations across Japan from May to September, 1982, are given in pCi/kg and mCi/km 2 , respectively. The methods of the collection and pretreatment of samples, the preparation of samples for analysis, the separation of strontium-90 and cesium-137, the determination of stable strontium, calcium and potassium, and the counting are also described. Soil was collected in the spacious and flat area without past disturbance on the surface. Soil was taken from two layers of different depths, 0 to 5 cm and 5 to 20 cm. The sample solution was prepared and was neutralized with sodium hydroxide. After sodium carbonate was added, the precipitate of strontium and calcium carbonates was separated. The supernatant solution was retained for cesium-137 determination. After the radiochemical separation, the mounted precipitate was counted for activity using a low background beta counter normally for 60 min. The radioactivity ranged 6 to 1300 pCi/Kg for Sr-90 and 1 to 5000 pCi/Kg for Cs-137 in the sampling depth of 0 to 5 cm. (J.P.N.)

Physical barrier effect of geopolymeric waste form on diffusivity of cesium and strontium

Energy Technology Data Exchange (ETDEWEB)

Jang, J.G.; Park, S.M.; Lee, H.K., E-mail: haengki@kaist.ac.kr

2016-11-15

Highlights: • Physical immobilization of radionuclides in geopolymer was quantitatively assessed. • Fly ash-based geopolymer showed excellent immobilization performance. • Diffusivity of soluble Cs and Sr was highly correlated with critical pore diameter. - Abstract: The present study investigates the physical barrier effect of geopolymeric waste form on leaching behavior of cesium and strontium. Fly ash-based geopolymers and slag-blended geopolymers were used as solidification agents. The leaching behavior of cesium and strontium from geopolymers was evaluated in accordance with ANSI/ANS-16.1. The diffusivity of cesium and strontium in a fly ash-based geopolymer was lower than that in Portland cement by a factor of 10{sup 3} and 10{sup 4}, respectively, showing significantly improved immobilization performance. The leaching resistance of fly ash-based geopolymer was relatively constant regardless of the type of fly ash. The diffusivity of water-soluble cesium and strontium ions were highly correlated with the critical pore diameter of the binder. The critical pore diameter of the fly ash-based geopolymer was remarkably smaller than those of Portland cement and slag-blended geopolymer; consequently, its ability physically to retard the diffusion of nuclides (physical barrier effect) was superior.

Surface Roughness and Grain Size Characterization of Annealing Temperature Effect For Growth Gallium and Tantalum Doped Ba0.5 Sr0.5TiO3Thin Film

Directory of Open Access Journals (Sweden)

Irzaman

2009-01-01

Full Text Available Thin films 10 % gallium oxide doped barium strontium titanate (BGST and 10 % tantalum oxide doped barium strontium titanate (BTST were prepared on p-type Si (100 substrates using chemical solution deposition (CSD method with 1.00 M precursor. The films were deposited by spin coating method with spinning speed at 3000 rpm for 30 seconds. The post deposition annealing of the films were carried out in a furnace at 200oC, 240oC, 280oC (low temperature for 1 hour in oxygen gas atmosphere. The surface roughness and grain size analysis of the grown thin films are described by atomic force microscope (AFM method at 5000 nm x 5000 nm area. The rms surface roughness BGST thin films at 5000 nm x 5000 nm area are 0.632 nm, 0.564 nm, 0.487 nm for temperature 200oC, 240oC, 280oC, respectively, whereas the grain size (mean diameter are 238.4 nm, 219.0 nm, 185.1 nm for temperature 200oC, 240oC, 280oC, respectively. In fact, to increase annealing temperature from 200oC to 280oC would result in decreasing the rms roughness and grain size. Therefore, rms roughness and grain size would have the strong correlation annealing temperature.

Pulsed electrodeposition for the synthesis of strontium-substituted calcium phosphate coatings with improved dissolution properties.

Science.gov (United States)

Drevet, Richard; Benhayoune, Hicham

2013-10-01

Strontium-substituted calcium phosphate coatings are synthesized by pulsed electrodeposition on titanium alloy (Ti6Al4V) substrates. Experimental conditions of the process are optimized in order to obtain a coating with a 5% atomic substitution of calcium by strontium which corresponds to the best observations on the osteoblast cells activity and on the osteoclast cells proliferation. The physical and chemical characterizations of the obtained coating are carried out by scanning electron microscopy associated to energy dispersive X-ray spectroscopy (EDXS) for X-ray microanalysis and the structural characterization of the coating is carried out by X-ray diffraction. The in vitro dissolution/precipitation properties of the coated substrates are investigated by immersion into Dulbecco's Modified Eagle Medium (DMEM) from 1h to 14 days. The calcium, phosphorus and strontium concentrations variations in the biological liquid are assessed by Induced Coupled Plasma - Atomic Emission Spectroscopy for each immersion time. The results show that under specific experimental conditions, the electrodeposition process is suitable to synthesize strontium-substituted calcium phosphate coatings. Moreover, the addition of hydrogen peroxide (H2O2) into the electrolytic solution used in the process allows us to observe a control of the strontium release during the immersion of the prosthetic materials into DMEM. © 2013.

Equilibrium sorption of cobalt, cesium, and strontium on Bandelier Tuff: analysis of alternative mathematical modeling

International Nuclear Information System (INIS)

Polzer, W.L.; Fuentes, H.R.; Essington, E.H.; Roensch, F.R.

1985-01-01

Sorption isotherms are derived from batch equilibrium data for cobalt, cesium and strontium on Bandelier Tuff. Experiments were conducted at an average temperature of 23 0 C and equilibrium was defined at 48 hours. The solute concentrations ranged from 0 to 500 mg/L. The radioactive isotopes 60 Co, 137 Cs, and 85 Sr were used to trace the sorption of the stable solutes. The Linear, Langmuir, Freundlich and a Modified Freundlich isotherm equations are evaluated. The Modified Freundlich isotherm equation is validated as a preferred general mathematical tool for representing the sorption of the three solutes. The empirical constants derived from the Modified Freundlich isotherm equation indicate that under dynamic flow conditions strontium will move most rapidly and cobalt least rapidly. On the other hand, chemical dispersion will be greatest for cesium and least for strontium. Hill Plots of the sorption data suggest that in the region of low saturation sorption of all three solutes is impeded by interactions among sorption sites; cobalt exhibits the greatest effect of interactions and strontium shows only a minimal effect. In the saturation region of 50% or more, sorption of cobalt is enhanced slightly by interactions among sorption sites whereas sorption of cesium and strontium appears to be independent of site interactions. 9 references, 4 figures, 2 tables

Strontium-90 and cesium-137 in service water (from June, 1982, to December, 1982)

International Nuclear Information System (INIS)

1982-01-01

Strontium-90 and cesium-137 in service water measured at 19 locations across Japan from June to December, 1982, are given in pCi/l, respectively. The methods of the collection and pretreatment of samples, the preparation of samples for analysis, the separation of strontium-90 and cesium-137, and the counting are also described. Service water was collected at an intake of the water-treatment plant and at the tap. The sample was then passed through a cation exchange column. Strontium and cesium were eluted with hydrochloric acid from the cation exchange column. The sample solution prepared was neutralized with sodium hydroxide. After sodium carbonate was added, the precipitate of strontium and calcium carbonates was separated. The supernatant solution was retained for cesium-137 determination. After the radiochemical separation, the mounted precipitate was counted for activity using a low background beta counter normally for 60 min. The radioactivity ranged 0.01 to 0.10 pCi/l for Sr-90 and 0.001 to 0.010 pCi/l for Cs-137 in the service water. (J.P.N.)

Structural and magnetic properties of conventional and microwave treated Ni-Zr doped barium strontium hexaferrite

Energy Technology Data Exchange (ETDEWEB)

Kanagesan, S., E-mail: kanagu1980@gmail.com [Center for Materials Science and Nano Devices, Department of Physics, SRM University, Kattankulathur 603203, Tamil Nadu (India); Jesurani, S. [Center for Materials Science and Nano Devices, Department of Physics, SRM University, Kattankulathur 603203, Tamil Nadu (India); Department of Physics, Jeyaraj Annapackium College for Women, Periyakulam 625601, Tamil Nadu (India); Velmurugan, R. [Center for Materials Science and Nano Devices, Department of Physics, SRM University, Kattankulathur 603203, Tamil Nadu (India); Prabu, S. [Department of Chemistry, S.K.P. Engineering College, Anna University of Technology Chennai, Thiruvannamalai 606 611, Tamil Nadu (India); Kalaivani, T. [Center for Materials Science and Nano Devices, Department of Physics, SRM University, Kattankulathur 603203, Tamil Nadu (India)

2012-02-15

Highlights: Black-Right-Pointing-Pointer Saturation magnetization increases whereas the coercivity decreases. Black-Right-Pointing-Pointer The transition from hard phase to soft phase. Black-Right-Pointing-Pointer Therefore, it is used for high-density magnetic recording applications. -- Abstract: M-type hexaferrites of component B{sub 0.5}Sr{sub 0.5}Fe{sub 12-2x}Ni{sub x}Zr{sub x}O{sub 19} 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 H{sub c} decreases remarkably with increasing Ni and Zr ions content. It was found that the particle size could be effectively decreased and coercivity H{sub c} could easily be controlled by varying the concentration (x) without significantly decreasing saturation magnetization. In particular, Ba{sub 0.5}Sr{sub 0.5}Fe{sub 12-2x}Ni{sub x}Zr{sub x}O{sub 19} 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.

The determination of initial ratio of strontium isotope in rocks and its geological application

International Nuclear Information System (INIS)

Ying Junlong; Zhao Puyun; Lin Xiulan

1989-04-01

The method to determine the initial ratio of strontium isotopes existed in rocks of poor rubidium and rich strontium and main carrier minerals is introduced. The initial ratio obtained from this method is equivalent to that acquired by Rb-Sr isochrone. Based on this result, information on regional rock genesis and mineralization regularities can be provided. It has great significance in the research on activities of ancient continental margin and material sources as well as their evolution. The migration of rock, and ore-forming materials, matallogenetic mechanism and its distribution in the space and time evolution are studied by using these data. In conclusion, the determination of strontium isotopes has broad prospects in the geological research

Bench-scale treatability studies for simulated incinerator scrubber blowdown containing radioactive cesium and strontium

International Nuclear Information System (INIS)

Coroneos, A.C.; Taylor, P.A.; Arnold, W.D. Jr.; Bostick, D.A.; Perona, J.J.

1994-12-01

The purpose of this report is to document the results of bench-scale testing completed to remove 137 Cs and 90 Sr from the Oak Ridge K-25 Site Toxic Substances Control Act (TSCA) Incinerator blowdown at the K-25 Site Central Neutralization Facility, a wastewater treatment facility designed to remove heavy metals and uranium from various wastewaters. The report presents results of bench-scale testing using chabazite and clinoptilolite zeolites to remove cesium and strontium; using potassium cobalt ferrocyanide (KCCF) to remove cesium; and using strontium chloride coprecipitation, sodium phosphate coprecipitation, and calcium sulfate coprecipitation to remove strontium. Low-range, average-range, and high-range concentration blowdown surrogates were used to complete the bench-scale testing

Conductivity and thermodynamic characteristic of superionic transition in strontium chloride

International Nuclear Information System (INIS)

Voronin, B.M.; Prisyazhnyj, V.D.

1989-01-01

Electric conductivity of strontium polycrystalline chloride in the wide temperature range including melting point is measured. Reciprocally caused anomalous behaviour of kinetic and thermodynamic properties, which relates to peculiarities of salt transition to a superionic state is established in the region of high temperatures. Thermodynamic functions corresponding to crystal anion sublattice disordering are determined and characterized. Comparative analysis of data on strontium chloride and other structural-like salts testifies about step-by-step washing-out character of superionic transition, and the depth of transition (the degree of disordering) reached at melting points relates regularly to relative sizes of cations and anions in the fluorite lattice

Application of La-Doped SrTiO3 in Advanced Metal-Supported Solid Oxide Fuel Cells

Directory of Open Access Journals (Sweden)

Sabrina Presto

2018-03-01

Full Text Available Composite materials frequently allow the drawbacks of single components to be overcome thanks to a synergistic combination of material- and structure-specific features, leading to enhanced and also new properties. This is the case of a metallic-ceramic composite, a nickel-chromium-aluminum (NiCrAl foam impregnated with La-doped Strontium Titanate (LST. This particular cermet has very interesting properties that can be used in different fields of application, namely: mechanical robustness provided by the metal foam; and chemical stability in harsh conditions of temperature and atmosphere by promotion of a thin protective layer of alumina (Al2O3; high electronic conductivity given by a percolating ceramic conducting phase, i.e., La-doped Strontium Titanate. In this paper, its application as a current collector in a metal-supported Solid Oxide Fuel Cells (SOFC was studied. Firstly, the electronic properties of different compositions, stoichiometric and under stoichiometric, of LST were analyzed to choose the best one in terms of conductivity and phase purity. Then, LST chemical stability was studied in the presence of Al2O3 at different temperatures, gas compositions and aging times. Finally, stability and conductivity of LST-impregnated NiCrAl foam composite materials were measured, and LST was found to be fully compatible with the NiCrAl foam, as no reactions were detected in oxidizing and reducing atmosphere after up to 300 h operation at 750 °C and 900 °C between the Al2O3 layer and LST. Results showed that the composite is suitable as a current collector in innovative designs of metal-supported SOFC, like the Evolve cell, in which the metallic part is supposed not only to provide the structural stability to the cell, but also to play the role of current collector due to the impregnation of ceramic material.

Laser Stabilization with Laser Cooled Strontium

DEFF Research Database (Denmark)

Christensen, Bjarke Takashi Røjle

The frequency stability of current state-of-the-art stabilized clock lasers are limited by thermal fluctuations of the ultra-stable optical reference cavities used for their frequency stabilization. In this work, we study the possibilities for surpassing this thermal limit by exploiting the nonli......The frequency stability of current state-of-the-art stabilized clock lasers are limited by thermal fluctuations of the ultra-stable optical reference cavities used for their frequency stabilization. In this work, we study the possibilities for surpassing this thermal limit by exploiting...... the nonlinear effects from coupling of an optical cavity to laser cooled atoms having a narrow transition linewidth. Here, we have realized such a system where a thermal sample of laser cooled strontium-88 atoms are coupled to an optical cavity. The strontium-88 atoms were probed on the narrow 1S0-3P1 inter......-combination line at 689 nm in a strongly saturated regime. The dynamics of the atomic induced phase shift and absorption of the probe light were experimentally studied in details with the purpose of applications to laser stabilization. The atomic sample temperature was in the mK range which brought this system out...

Application of inductively coupled plasma-mass spectrometry (ICP-MS) and quality assurance to study the incorporation of strontium into bone, bone marrow, and teeth of dogs after one month of treatment with strontium malonate

DEFF Research Database (Denmark)

Raffalt, Anders Christer; Andersen, Jens Enevold Thaulov; Christgau, S.

2008-01-01

with strontium malonate, strontium levels increased from 76 +/- 9 mu g g(-1) in placebo-treated dogs to levels of 7.2 +/- 1.7 mg g(-1), 9.5 +/- 2.7 mg g(-1), and 9.8 +/- 2.7 mg g(-1) in groups treated with 300, 1000, and 3000 mg kg(-1) day(-1), respectively. Strontium induced a highly significant increase......% for the groups treated with 300, 1000, and 3000 mg kg(-1) day(-1), respectively. For males the corresponding values were -44%, +142%, +194%, and +247% increases in BSAP in the placebo, 300, 1000, and 3000 mg kg(-1) day(-1) groups respectively....

Review and assessment of technologies for the separation of strontium from alkaline and acidic media

International Nuclear Information System (INIS)

Orth, R.J.; Kurath, D.E.

1994-01-01

A literature survey has been conducted to identify and evaluate methods for the separation of strontium from acidic and alkaline media as applied to Hanford tank waste. The most promising methods of solvent extraction, precipitation, and ion exchange are described. The following criteria were used for evaluating the separation methods: Appreciable strontium removal must be demonstrated; Strontium selectivity over bulk components must be demonstrated; The method must show promise for evolving into a practical and fairly simple process; The process should be safe to operate; The method must be robust (i.e., capable of separating strontium from various waste types); Secondary waste generation must be minimized; and The method must show resistance to radiation damage. The methods discussed did not necessarily satisfy all of the above criteria; thus, key areas requiring further development are also given for each method. Less promising solvent extraction, precipitation, and ion exchange methods were also identified; areas for potential development are included in this report

Transesterification of soybean oil catalyzed by Sr-doped cinder

International Nuclear Information System (INIS)

Nasreen, Sadia; Liu, Hui; Khan, Romana; Zhu, Xiao-chan; Skala, Dejan

2015-01-01

Highlights: • Sr-doped cinder catalyst was prepared and used for biodiesel synthesis. • A 99% of triglycerides conversion was achieved under optimal reaction conditions. • SrAl 2 Si 2 O 8 and Sr 5 Al 8 O 1 are determined as dominant compounds which are responsible for high catalytic activity. • Catalyst exhibits high activity and can be easily recovered and regenerated. • The Sr-doped cinder catalyst is used in 14 repeated runs. - Abstract: The Strontium doped cinder was prepared using the wet impregnation method and analyzed as catalyst for biodiesel synthesis. Different procedure for cinder impregnation were investigated (temperature and duration of catalyst calcinations, the concentration of SrCl 2 solution) and optimal condition was established: impregnation 20 g of cinder 2–5 mm particles with 0.2 M SrCl 2 solution followed by calcinations at 1000 °C for 4 h. The Sr-cinder activity was tested at 90–200 °C using 1–5% mass of catalyst with different molar ratio of methanol to soybean oil (from 9 to 36). The maximum triglycerides (TG) conversion of 99.0% with the Fatty Acid Methyl Esters (FAME) yield of 97.1% was obtained by using 4% catalyst at 180 °C, for 1 h, and methanol/oil molar ratio 24:1. Influence of free fatty acid (FFA) and water in soybean oil on catalyst activity was analyzed, too. The catalyst could be used for 14 times with TG conversion and FAME yield above 90% and 80% respectively. The Sr-doped cinder catalysts before and after transesterification were characterized using BET surface area, basic strength, X-ray diffraction (XRD), scanning electron microscopy (SEM) and ICP-AAS. Results showed that the formation of SrAl 2 Si 2 O 8 and Sr 5 Al 8 O 17 complexes should be the main reason for the catalytic activity of prepared catalyst. Slow decrease of catalyst activity during its repeated use is result of Sr–Al-glycerolate formation in reaction between Sr–Al complexes and glycerol

Removal of cesium and strontium from low active waste solutions by zeolites

International Nuclear Information System (INIS)

Jain, Savita; Ramaswamy, M.; Theyyunni, T.K.

1994-01-01

Ion exchange, crystallographic and thermal characteristics of sodium, cesium and strontium forms of locally available synthetic zeolites have been investigated. X-ray and differential thermal analyses have confirmed that the synthetic materials AR1 and 4A belonged to the mordenite and A type families of zeolites respectively. Equilibrium uptake of cesium and strontium ions by sodium forms of zeolite was studied as a function of time, pH and sodium concentration. It was found that the rate of sorption by AR1 was higher than that by 4A. In regard to pH, distribution of nuclides on zeolites was found to pass through maxima at a pH value of around 9. Sodium ion interfered with the sorption of cesium and strontium by zeolites. However, at sodium concentration ≤ 0.01 M, distribution coefficient values for these nuclides were sufficiently high to merit consideration of these zeolites for low level waste treatment. Lab-scale column runs using 5 ml beds of materials showed that the zeolites AR1 and 4A were very effective in removing cesium and strontium nuclides respectively from large volumes (a decontamination factor of 50 for a throughput of 6000 bed volumes) of actual low level waste solutions. Thus, the zeolite system has a potential future for large scale application in the treatment of low level wastes. (author). 6 refs., 5 figs., 6 tabs

Impact of Strontium Nitrate and Sodium Permanganate Addition on Solid-Liquid Separation of SRS High Level Waste

International Nuclear Information System (INIS)

Poirier, M.R.

2002-01-01

As a pretreatment step for the caustic side solvent extraction (CSSX) flowsheet, the process contacts the incoming salt solution containing entrained sludge with monosodium titanate (MST) to adsorb strontium and actinides. An operation filters the resulting slurry to remove the sludge and MST. Previous work for the River Protection Program at Hanford suggests that addition of strontium nitrate and sodium permanganate for strontium and actinide removal, rather than MST, improves the filtration rate for comparable waste streams

Strontium-90 sorption from fresh waters in the process of barium manganite modification

International Nuclear Information System (INIS)

Ryzhen'kov, A.P.; Egorov, Yu.V.

1995-01-01

Strontium-90 extraction by barium manganite from fresh water (natural non-salty water in open ponds) may be increased adding to the solution the sulfate anion containing reagents that modify a sorbent and chemically bind a sorbate. Heterogeneous anion-exchanging reaction of barium manganite transformation into barium sulfate-manganese dioxide and simultaneous coprecipitation of strontium sulfate (microelement) occur as a result of it. 9 refs., 4 figs., 1 tab

Reaction of strontium zirconate with refractory borides and carbides

International Nuclear Information System (INIS)

Bowker, J.C.; Lane, J.E.

1990-01-01

The chemical compatibility of the potential oxide ceramic matrix material, strontium zirconate, and several different potential nonoxide ceramic reinforcement materials was studied by elevated temperature reaction. Results are presented in this paper

Energy dispersive x-ray fluorescence spectrometric determination of phosphorus, calcium, iron, zinc, and strontium in human bones

International Nuclear Information System (INIS)

Ohta, Akishige; Matsubayashi, Takashi; Itoman, Moritoshi

1981-01-01

Phosphorus, calcium, iron, zinc and strontium in a human bone extracted by surgery were determined by energy dispersive X-ray fluorescence spectrometry. The bone was decomposed with nitric acid, then diluted with water. A specific quantity of the solution was naturally dried on polyethylene film, and subjected to X-ray analysis. For determining the calibration curves in a mixture of phosphorus, calcium, iron, zinc and strontium, for the analysis of phosphorus and calcium, germanium was used as the secondary target and aluminum as the filter; and for the analysis of iron, zinc and strontium, molybdenum and molybdenum-aluminum were used, respectively. Consequently, the calibration curves were able to be obtained with high precision in the ranges from 5 to 500 μg of phosphorus, from 1 to 50 μg of calcium and from 0.1 to 1.0 μg of iron, zinc and strontium. In this way, in 1 mg of the human bone by wet weight, phosphorus, calcium, iron, zinc and strontium were able to be determined. (J.P.N.)

Removal of Strontium from Drinking Water by Conventional Treatment and Lime Softening in Bench-Scale Studies

Science.gov (United States)

The United States Environmental Protection Agency Contaminant Candidate List 3 lists strontium as a contaminant for potential regulatory consideration in drinking water. There is very little data available on strontium removal from drinking water. As a result, there is an immedia...

Migration Behaviour of Strontium in Czech Bentonite Clay

Directory of Open Access Journals (Sweden)

Lucie Baborova

2016-09-01

Full Text Available The study deals with sorption and diffusion behaviour of strontium in Czech bentonite B75. The study is a part of a research on reactive transport of radioactive contaminants in barrier materials of a deep geological repository of radioactive waste in the Czech Republic. Series of sorption and diffusion experiments with Sr and non-activated Ca bentonite B75 produced in the Czech Republic were performed in two background solutions (CaCl2 and NaCl. On the basis of sorption batch experiments the kinetics of strontium sorption on bentonite was assessed and the sorption isotherms for various experimental conditions were obtained. As a result of performed diffusion experiments the parameters of diffusion (i.e. effective diffusion coefficient De and apparent diffusion coefficient Da were determined. The observed discrepancies between sorption characteristics obtained from the sorption and diffusion experiments are discussed.

Strontium-90 and cesium-137 in service water

International Nuclear Information System (INIS)

1979-01-01

Prefectural public health laboratories and institutes and Japan Chemical Analysis Center have analysed the contents of strontium-90 and cesium-137 in service water under the commission of Science and Technology Agency. At each prefectural public health laboratories and institutes, 100 literes of service water (8 prefectures, water from the intake of each station of water works) and tap water (32 prefectures) were collected as sample twice a year. The samples were filtrated with large filter papers after addition and mixture of both some carries. The filtration was then applied on a column filled the sodium cation exchange resin, and all the cations were absorbed on it. These resin and filter papers were collected at Japan Chemical Analysis Center. At Japan Chemical Analysis Center, these collected samples were radiochemically analysed for strontium-90 and cesium-137 using the method applied for the analysis of rain and dry fallout materials. (author)

Comparison of modification with strontium and the refining with antimony in A 356 aluminium alloys

International Nuclear Information System (INIS)

Fuoco, Ricardo; Correa, Edison Roberto; Correa, Alzira V.O.; Bocalini Junior, Mario

1992-01-01

Strontium and Antimony treated A356 aluminium alloy samples were metallographically characterized in the as cast and solution and aged conditions. Antimony treated alloy has shown slower spheroidizing kinetics of the Silicon particles during solution treatment, lower porosity level and higher tensile strength and elongation than Strontium treated one. (author)

10 CFR 32.103 - Schedule D-prototype tests for ice detection devices containing strontium-90.

Science.gov (United States)

2010-01-01

... water and the strontium-90 shall be considered leakage. (e) Observations. After each of the tests... 10 Energy 1 2010-01-01 2010-01-01 false Schedule D-prototype tests for ice detection devices... § 32.103 Schedule D—prototype tests for ice detection devices containing strontium-90. An applicant for...

The removal of radioactive strontium from aqueous solutions by foam separation

International Nuclear Information System (INIS)

Shakir, K.; Aziz, M.; Atomic Energy Establishment, Cairo

1979-01-01

The flotation of strontium ions from aqueous solutions has been investigated using cetyl trimethyl ammonium bromide, potassium laurate, sodium lauryl sulphate or Aeroslo 18 as collector. Aerosol 18 proved to be the most suitable. With this reagent strontium removals of about 97.5% - 99% could be achieved for metal ion concentrations ranging from 1 x 10 -7 M (or probably less) to 1.3 x 10 -4 M. The effects of pH, collector concentration, ionic strength, gas flow rate and period of bubbling were determined and the optimum flotation conditions have been established. (orig.) [de

Energy transfer in Pr3+ and Mn2+ co-doped SrB6O10 and SrB4O7

International Nuclear Information System (INIS)

Chen Yonghu; Yan Wuzhao; Shi Chaoshu

2007-01-01

The luminescent properties of Pr 3+ and Mn 2+ -doped SrB 6 O 10 and SrB 4 O 7 powder samples were investigated from the point of view of energy transfer between Pr 3+ and Mn 2+ . The emission from the 1 S 0 level of Pr 3+ was found in the SrB 6 O 10 :Pr 3+ sample as well as in the SrB 4 O 7 :Pr 3+ sample, indicating the 1 S 0 level is below the lowest 4f5d energy level in these hosts. The spectral overlaps between the emission spectra of Pr 3+ -doped samples and the excitation spectra of Mn 2+ -doped sample were found in both kinds of strontium borates. These spectral overlaps are in favor of the energy transfer from Pr 3+ to Mn 2+ . However, in the emission spectra of the SrB 6 O 10 :Pr 3+ , Mn 2+ , no indication of energy transfer was observed, though the emission spectra of SrB 4 O 7 :Pr 3+ , Mn 2+ did show evidence of energy transfer from Pr 3+ to Mn 2+ . The possible reasons were discussed

Nitrate absorption and strontium accumulation. Final report, 1 August 1973--31 December 1976

International Nuclear Information System (INIS)

Jackson, W.A.

1977-03-01

Two basic objectives of this study to determine how strontium translocation, and discrimination between strontium and calcium in plants are influenced by nitrate uptake, assimilation, and translocation, and to characterize the relationships between nitrate uptake, nitrate assimilation, and nitrate translocation. Results are reported from studies using maize seedlings in which 85 Sr and 45 Ca were used as tracers. A list is included of publications that report the results of related studies

Physical and chemical grounds of electrolytic fabrication of aluminium-strontium alloying composition

International Nuclear Information System (INIS)

Lysenko, A.P.

1998-01-01

It was revealed via study of literature sources that usage of alloying composition of strontium (not of sodium) is more expedient in modification of silumin-type alloys. In this case modification effect is keeping during long holdings and in repeated meltings. Electrolytic decomposition of strontium chloride with usage of liquid aluminium cathode is the most simple and cheap method for fabrication of alloying composition. The operation scheme for production of Al-Sr alloy was proposed in this work on the base of thermodynamic analysis

Effects of strontium ranelate on spinal osteoarthritis progression

DEFF Research Database (Denmark)

Bruyere, O; Delferriere, D; Roux, C

2008-01-01

OBJECTIVE: The aim of this study was to determine whether a 3-year treatment with strontium ranelate could delay the progression of spinal osteoarthritis (OA). METHODS: This study was a post-hoc analysis of pooled data from the Spinal Osteoporosis Therapeutic Intervention (SOTI) and TReatment...

Strontium-90 and cesium-137 in tea (Japanese tea)

International Nuclear Information System (INIS)

1982-01-01

Strontium-90 and cesium-137 in tea (Japanese tea) were determined. Five hundred grams of manufactured green tea was collected from six sampling locations in Japan. The results are shown in a table. (Namekawa, K.)

Analyses and quantitative determination of the strontium radioisotopes 89 and 90 in milk powder; Recherche et dosage des isotopes radioactifs 89 et 90 du strontium dans le lait en poudre

Energy Technology Data Exchange (ETDEWEB)

Jeanmaire, L; Michon, G [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1959-07-01

The authors describe a procedure for the determination of the strontium radioisotopes 89 and 90. The concentration of strontium is made possible by the insolubility of its nitrate salt in strong nitric acid which allows the removal of greatest part of calcium. The purification is performed on a cation exchange column. The amount of radioisotope 90 is determined by means of its daughter product yttrium 90 necessary calibrations and computations are treated in special paragraphs. With regard to the reproducibility of the measurements, the fluctuations are less than 20 per cent. This seems satisfaction for such a technique which have great sensibility while being long and necessitative great carefulness. (author) [French] Les auteurs decrivent une technique de dosage des isotopes 89 et 90 du strontium. La concentration du strontium est assuree grace a l'insolubilite de son nitrate dans l'acide nitrique concentre, ce qui permet d'eliminer la plus grande partie du Ca. La purification se fait sur une colonne echangeuse de cations. L'isotope 90 est dose grace a son descendant l'yttrium 90. Les etalonnages et calculs necessaires font l'objet de paragraphes detailles. En ce qui concerne la reproductibilite des mesures, les fluctuations sont inferieures a 20 pour cent, ce qui semble satisfaisant devant la grande sensibilite de la methode qui reste cependant longue et delicate. (auteur)

Strontium isotope detection of brine contamination in the East Poplar oil field, Montana

Science.gov (United States)

Peterman, Zell E.; Thamke, Joanna N.; Futa, Kiyoto; Oliver, Thomas A.

2010-01-01

Brine contamination of groundwater in the East Poplar oil field was first documented in the mid-1980s by the U.S. Geological Survey by using hydrochemistry, with an emphasis on chloride (Cl) and total dissolved solids concentrations. Supply wells for the City of Poplar are located downgradient from the oil field, are completed in the same shallow aquifers that are documented as contaminated, and therefore are potentially at risk of being contaminated. In cooperation with the Office of Environmental Protection of the Fort Peck Tribes, groundwater samples were collected in 2009 and 2010 from supply wells, monitor wells, and the Poplar River for analyses of major and trace elements, including strontium (Sr) concentrations and isotopic compositions. The ratio of strontium-87 to strontium-86 (87Sr/86Sr) is used extensively as a natural tracer in groundwater to detect mixing among waters from different sources and to study the effects of water/rock interaction. On a plot of the reciprocal strontium concentration against the 87Sr/86Sr ratio, mixtures of two end members will produce a linear array. Using this plotting method, data for samples from most of the wells, including the City of Poplar wells, define an array with reciprocal strontium values ranging from 0.08 to 4.15 and 87Sr/86Sr ratios ranging from 0.70811 to 0.70828. This array is composed of a brine end member with an average 87Sr/86Sr of 0.70822, strontium concentrations in excess of 12.5 milligrams per liter (mg/L), and chloride concentrations exceeding 8,000 mg/L mixing with uncontaminated water similar to that in USGS06-08 with 18.0 mg/L chloride, 0.24 mg/L strontium, and a 87Sr/86Sr ratio of 0.70811. The position of samples from the City of Poplar public-water supply wells within this array indicates that brine contamination has reached all three wells. Outliers from this array are EPU-4G (groundwater from the Cretaceous Judith River Formation), brine samples from disposal wells (Huber 5-D and EPU 1-D

Polymorphism’s assessment of children’s candidate genes associated with low-level long-term exposure to strontium in drinking water

Directory of Open Access Journals (Sweden)

N.V. Zaitseva

2015-12-01

Full Text Available A sequencing of the candidate genes of the pupils, exposed to strontium by the method of targeted resequencing has been performed. It is shown, that under conditions of increased revenues of strontium in drinking water the number of polymorphonuclear altered portions of candidate genes increases. As a result of the targeted resequencing in conditions of strontium exposure, the maximum polymorph modifications of the following genes are defined: sulfotransferase 1A1 (SULT1A1 and methylenetetrahydrofolate. It was shown that the structure of the mutations in conditions of the strontium exposure was characterized by the formation of defects in the gene mapping detoxification (38.5 % of all mutations and immunoregulation (22.5 %. Analysis of the cause-effect relationships in the system "factor - the number of mutations" revealed that candidate genes reflecting strontium exposure conditions (content of strontium in drinking water is 1.3 MAC, are genes: cytochrome P450, glutathione - transaminase (detoxification; dopamine (CNS, interleukin 17 and the major histocompatibility complex (immune system, methylene-tetra-hydro-folate-reductase (reproduction.

Strontium-90 measurements in Switzerland

International Nuclear Information System (INIS)

Friedli, C.; Geering, J.J.; Lerch, P.

1988-01-01

Strontium-90 contamination in Switzerland has been measured since the sixties. The determination of 90 Sr in human vertebrae, milk-teeth, milk and wine have shown a maximum activity between 1964 and 1966. Since 1976, the survey has been extended to the food chain. After the Chernobyl accident, the measurements indicated a significative 90 Sr contamination in the Tessin and the north-east of Switzerland. The partition of 90 Sr in wheat has been determined and transfer factors are given for the milk - cheese - whey chain

Programmed gradient descent biosorption of strontium ions by Saccaromyces cerevisiae and ashing analysis: A decrement solution for nuclide and heavy metal disposal

Energy Technology Data Exchange (ETDEWEB)

Liu, Mingxue [Life Science and Engineering College, Southwest University of Science and Technology, Mianyang, 621010 (China); Key Laboratory of Solid Waste Treatment and Resource Recycle, Ministry of Education of China, Mianyang, 621010 (China); Dong, Faqin, E-mail: fqdong@swust.edu.cn [Key Laboratory of Solid Waste Treatment and Resource Recycle, Ministry of Education of China, Mianyang, 621010 (China); Zhang, Wei [Key Laboratory of Solid Waste Treatment and Resource Recycle, Ministry of Education of China, Mianyang, 621010 (China); Nie, Xiaoqin [Fundamental Science on Nuclear Wastes and Environmental Safety Laboratory, Mianyang, 621010 (China); Sun, Shiyong [Key Laboratory of Solid Waste Treatment and Resource Recycle, Ministry of Education of China, Mianyang, 621010 (China); Wei, Hongfu; Luo, Lang; Xiang, Sha; Zhang, Gege [Life Science and Engineering College, Southwest University of Science and Technology, Mianyang, 621010 (China)

2016-08-15

Highlights: • A programmed gradient descent biosorption process was designed. • The adsorption and bioaccumulation quantity of strontium ions by yeast cell were measured. • The decrement of biosorbents after biosorption by ashing was analyzed. • A technological flow process of decrement solution for waste disposal was proposed. - Abstract: One of the waste disposal principles is decrement. The programmed gradient descent biosorption of strontium ions by Saccaromyces cerevisiae regarding bioremoval and ashing process for decrement were studied in present research. The results indicated that S. cerevisiae cells showed valid biosorption for strontium ions with greater than 90% bioremoval efficiency for high concentration strontium ions under batch culture conditions. The S. cerevisiae cells bioaccumulated approximately 10% of strontium ions in the cytoplasm besides adsorbing 90% strontium ions on cell wall. The programmed gradient descent biosorption presented good performance with a nearly 100% bioremoval ratio for low concentration strontium ions after 3 cycles. The ashing process resulted in a huge volume and weight reduction ratio as well as enrichment for strontium in the ash. XRD results showed that SrSO{sub 4} existed in ash. Simulated experiments proved that sulfate could adjust the precipitation of strontium ions. Finally, we proposed a technological flow process that combined the programmed gradient descent biosorption and ashing, which could yield great decrement and allow the supernatant to meet discharge standard. This technological flow process may be beneficial for nuclides and heavy metal disposal treatment in many fields.

Ischaemic cardiac events and use of strontium ranelate in postmenopausal osteoporosis: a nested case-control study in the CPRD.

Science.gov (United States)

Cooper, C; Fox, K M; Borer, J S

2014-02-01

We explored the cardiac safety of the osteoporosis treatment strontium ranelate in the UK Clinical Practice Research Datalink. While known cardiovascular risk factors like obesity and smoking were associated with increased cardiac risk, use of strontium ranelate was not associated with any increase in myocardial infarction or cardiovascular death. It has been suggested that strontium ranelate may increase risk for cardiac events in postmenopausal osteoporosis. We set out to explore the cardiac safety of strontium ranelate in the Clinical Practice Research Datalink (CPRD) and linked datasets. We performed a nested case-control study. Primary outcomes were first definite myocardial infarction, hospitalisation with myocardial infarction, and cardiovascular death. Cases and matched controls were nested in a cohort of women treated for osteoporosis. The association with exposure to strontium ranelate was analysed by multivariate conditional logistic regression. Of the 112,445 women with treated postmenopausal osteoporosis, 6,487 received strontium ranelate. Annual incidence rates for first definite myocardial infarction (1,352 cases), myocardial infarction with hospitalisation (1,465 cases), and cardiovascular death (3,619 cases) were 3.24, 6.13, and 14.66 per 1,000 patient-years, respectively. Obesity, smoking, and cardiovascular treatments were associated with significant increases in risk for cardiac events. Current or past use of strontium ranelate was not associated with increased risk for first definite myocardial infarction (odds ratio [OR] 1.05, 95 % confidence interval [CI] 0.68-1.61 and OR 1.12, 95 % CI 0.79-1.58, respectively), hospitalisation with myocardial infarction (OR 0.84, 95 % CI 0.54-1.30 and OR 1.17, 95 % CI 0.83-1.66), or cardiovascular death (OR 0.96, 95 % CI 0.76-1.21 and OR 1.16, 95 % CI 0.94-1.43) versus patients who had never used strontium ranelate. Analysis in the CPRD did not find evidence for a higher risk for cardiac events associated

Dielectric Strontium Zirconate Sprayed by a Plasma Torch.

Czech Academy of Sciences Publication Activity Database

Ctibor, Pavel; Sedláček, J.; Janata, Marek

2017-01-01

Roč. 10, č. 4 (2017), s. 225-230 ISSN 2008-2134 Institutional support: RVO:61389021 Keywords : Plasma spraying * Electrical properties * Strontium Zirconate * Insulators Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass OBOR OECD: Ceramics www.pccc.icrc.ac.ir/Articles/18/1/18/1010/

A thermoelectric-conversion power supply system using a strontium heat source of high-level radioactive nuclear waste

International Nuclear Information System (INIS)

Chikazawa, Yoshitaka

2011-01-01

A thermoelectric-conversion power supply system with radioactive strontium in high-level radioactive waste has been proposed. A combination of Alkali Metal Thermo-Electric Conversion (AMTEC) and a strontium fluoride heat source can provide a compact and long-lived power supply system. A heat source design with strontium fluoride pin bundles with Hastelloy cladding and intermediate copper has been proposed. This design has taken heat transportation into consideration, and, in this regard, the feasibility has been confirmed by a three-dimensional thermal analysis using Star-CD code. This power supply system with an electric output of 1 MW can be arranged in a space of 50 m 2 and approximately 1.1 m height and can be operated for 15 years without refueling. This compact and long-lived power supply is suitable for powering sources for remote places and middle-sized ships. From the viewpoint of geological disposal of high-level waste, the proposed power supply system provides a financial base for strontium-cesium partitioning. That is, a combination of minor-actinide recycling and strontium-cesium partitioning can eliminate a large part of decay heat in high-level waste and thus can save much space for geological disposal. (author)

Synthesis and characterization of strontium carboxylates at room temperature and at high temperature in autoclave vessels

DEFF Research Database (Denmark)

Christgau, Stephan; Ståhl, Kenny; Andersen, Jens Enevold Thaulov

2006-01-01

A novel method was developed for synthesis of strontium coordination compounds in high yields. The synthesis proceeded along three pathways that provided strontium salts in high purity and high yields, close to 100%, as confirmed by flame atomic absorption spectroscopy (FAAS) and powder x......-ray crystallography. Optimum conditions were found at T = 120-1400C, a base-to-acid ratio of 1.2 and 15 min. of reaction-time in an autoclave vessel. Large crystals were readily obtained within a time period of hours. The crystal structures of strontium D-glutamate hexahydrate (I) and strontium di-(hydrogen L......-glutamate) pentahydrate (II) were confirmed by X-ray powder diffraction at 295 K and Rietveld refinements (I: Space group P212121, Z=4, a=7.3519(2), b=8.7616(2), c=20.2627(5) Å, and II: Space group P21, Z=2, a=8.7243(1), b=7.2635(1), c=14.6840(2) Å, β=100.5414(7) °). Synthesis at room temperature provided four additional...

Sorption of strontium on bentonites from Slovak deposits

International Nuclear Information System (INIS)

Kufcakova, J.; Galambos, M.; Rajc, P.

2005-01-01

Sorption on bentonite from different Slovak deposits / Jelsovy potok, Kopernica and Lieskove has been investigated under various experimental conditions, such as contact time, pH, sorbate concentrations, presence of complementary cation. The sorption of strontium from aqueous solutions was investigated using a radiometric determination of distribution coefficient, Kd. The individual solutions were labelled with radiotracer. Radiation stability has been investigated, the higher sorption parameters were observed for the irradiated bentonites /tab.l/ , which can be explained by the increase of specific surface and change of solubility of the irradiated samples of bentonite. The presence of complementary cations, Na + , K + , NH 4 + , Ca 2+ , Mg 2+ and Ba 2+ depresses the sorption of Sr on bentonite. In the case of bentonite Kopernica the effectiveness in reducing the sorption of strontium by cations followed the order K + 4 + + 2+ 2+ 2+ . Results indicate that the sorption of Sr + on bentonite will be affected by the presence of high concentrations of various salts in the waste water effluents. (author)

Strontium-90 and cesium-137 in total diet

International Nuclear Information System (INIS)

1977-01-01

Under the commission of Science and Technology Agency, Japan Chemical Analysis Center has analysed total diet samples collected from 30 prefectures (2 times per year), and determined to content of strontium-90 and cesium-137 in these samples. Each Prefectural public health laboratories and institutes have collected all the daily regular diet consumed for five persons, namely three meals and other eating between meals, for radiochemical analysis in polyethylene containers. These samples were collected to Japan Chemical Analysis Center after carbonization without smoke rising in the large stainless dish. At Japan Chemical Analysis Center, these samples were asked in an electric muffle furnance. And the ask to which both some carriers and hydrochloric acid were added, was destroyed under heating. The nuclides were dissolved into hydrochloric acid and filtrated, after it was added with nitric acid and heated to dryness. The filtrates was analysed for strontium-90 and cesium-137 using the method recommended by Science and Technology Agency. (author)

Physico-chemical studies for strontium sulfate radiation dosimeter

Directory of Open Access Journals (Sweden)

M.A.H. Rushdi

2015-04-01

Full Text Available Anhydrous strontium sulfate (SrSO4 has shown a promise candidate as a dosimeter for low dose applications producing unique EPR signals with γ-rays which it has a linear response relationship (r2 = 0.999 in the range of 1–100 Gy. The present study extended to evaluate the properties of strontium sulfate dosimeter in intermediate dose range of technology applications. It was observed that the intensity of the EPR signal at g = 2.01081 increases with a 3rd polynomial function in the range of 0.10–15 kGy. In addition, the radical (SO4− provides a stable signal with a good reproducibility (0.107%. Other physics characteristic including the collision of mass stopping power dependence of the system and the effect of atomic number in different energy regions were investigated. The uncertainty budget for high doses has obtained from the measurement with value of 3.57% at 2σ confidence level.

Bulletin of Materials Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

Strontium-incorporated calcium phosphates show potential in biomedical application, particularly the doped strontium may help in new bone formation. ... Department of Chemistry, Periyar University, Salem 636 011, India; Centre for Nanoscience and Nanotechnology, Periyar University, Salem 636 011, India; Department of ...

Ion-exchange properties of cesium and strontium into zeolites from sodium salt solutions

International Nuclear Information System (INIS)

Kanno, Takuji; Hashimoto, Hiroyuki; Ohtani, Tozo.

1978-01-01

The ion-exchange properties of cesium and strontium into zeolite from sodium salt solution has been studied in zeolite A, zeolite X, zeolite Y, mordenite and clinoptilolite. The distribution of cesium into mordenite from about 1 -- 2 M sodium chloride and sodium hydroxide solutions is considerably larger than that into zeolite A. The distribution coefficient for 2 M solution of sodium salts was about 300. Therefore, the separation of cesium from sodium salt solution is possible by using mordenite. The distribution of strontium into zeolites form 1 -- 2 M solutions of sodium chloride and sodium nitrate were in the order of zeolite A>zeolite X>zeolite Y asymptoticaly equals mordenite. The distribution coefficient of 230 was obtained for 1 M solutions of sodium salts. The anion in solutions had no effect on the distribution of cesium and strontium into zeolite from sodium salt solution. (author)

Strontium-90 and cesium-137 in freshwater (from Sept. 1983 to Dec. 1983)

International Nuclear Information System (INIS)

1983-01-01

Fresh water, 100 l each, was collected, and to which the carriers of strontium and cesium were added immediately after the sampling. The sample was vigorously stirred and filtered, and passed through a cation exchange column. Strontium and cesium were eluted with hydrochloric acid from the cation exchange column. The eluate was used for radiochemical analysis. The chemical separation of strontium-90 and cesium-137 was carried out, and the chemical yields were determined. The precipitates were counted for the activity using low background beta counters normally for 60 min. The net sample counting rate was corrected for the counter efficiency, recovery, self-absorption and decay, to obtain the radioactivity per sample aliquot, and the concentrations of these nuclides in the original samples were calculated. The data at six sampling locations in Japan from September to December, 1983, on fresh water are reported. (Kako, I.)

Strontium-90 and cesium-137 in soil (from Jun. 1983 to Sept. 1983)

International Nuclear Information System (INIS)

1983-01-01

Results are presented for the determination of strontium-90 and cesium-137 in soils in Japan. Twenty-seven sampling points were selected all over Japan from Hokkaido to Okinawa by the criteria that the points were spacious and flat without past disturbance and those located in a forest, in a stony area or inside of river banks should be avoided. Soils were taken from two layers of depth, 0 to 5 cm and 5 to 20 cm. After drying, soils were passed through a 2 mm sieve and were employed for radiochemical leaching, separation, and purification of strontium-90 or cesium-137. Radioactivity of strontium-90 or cesium-137 was determined with a low background beta counter normally for 60 minutes. Determined values are presented as pCi/kg and mCi/km 2 for two different depth layers. As for strontium-90 contents, they were ranged from 13.0 +- 3.3 pCi/kg-dry (Aomori, 5 to 20 cm) to 1300 +- 20 pCi/kg-dry (Oota, Shimane Pref., 0 to 5 cm), or from 1.1 +- 0.14 mCi/km 2 (Tsuyama, Okayama Pref., 0 to 5 cm) to 50.0 +- 1.7 mCi/km 2 (Sapporo, 5 to 20 cm). As for cesium-137 contents, they were ranged from 0.5 +- 2.2 pCi/kg-dry (Saga, 5 to 20 cm) to 4700 +- 40 pCi/kg-dry (Oota, Shimane Pref., 0 to 5 cm) or from 0.1 +- 0.42 mCi/km 2 (Saga, 5 to 20 cm) to 120.0 +- 2.0 mCi/km 2 (Oota, Shimane Pref., 5 to 20 cm), and the variance for cesium-137 values were larger than those for strontium-90. Seasonal or local tendency for the contents of the two nuclides were not clarified. (Takagi, S.)

Anion and cation diffusion in barium titanate and strontium titanate

International Nuclear Information System (INIS)

Kessel, Markus Franz

2012-01-01

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 3 single crystals has been studied by means of 18 O 2 / 16 O 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 pressure and temperature. The

Phonons in face-centred cubic calcium and strontium

International Nuclear Information System (INIS)

Singh, S.P.; Rathore, R.P.S.

1984-01-01

The axially symmetric and unpaired forces are employed to analyse the phonon dispersion and elastic behaviour of face centred cubic calcium and strontium which have so far not been studied adequately. The model with three parameters predicts the results which agree marvellously with the recently measured data. (author)

Strontium removal jar test dataset for all figures and tables.

Data.gov (United States)

U.S. Environmental Protection Agency — The datasets where used to generate data to demonstrate strontium removal under various water quality and treatment conditions. This dataset is associated with the...

Sorption and desorption of cesium and strontium on TA-2 and TA-41 soils and sediments

International Nuclear Information System (INIS)

Kung, K. Stephen; Li, Benjamin W.; Longmire, P.A.; Fowler, M.M.

1996-04-01

Current environmental monitoring has detected radioactive contaminants in alluvial groundwater, soils, and sediments in the TA-2 and TA-41 areas along the north central edge of Los Alamos National Laboratory. Because of this contamination, this study was initiated. The objective of this study is to quantify the sorptivity of cesium and strontium onto TA-2 and TA-41 site specific soil samples under a controlled environment in the laboratory. The purposes of this work are to determine cesium and strontium sorption coefficient for these sit specific soils and to evaluate the potential transport of cesium and strontium. Based on this information, a risk assessment and remediation strategy can be developed

Power series fitting of current-voltage characteristics of Al doped ZnO thin film-Sb doped (Ba{sub 0.8}Sr{sub 0.2})TiO{sub 3} heterojunction diode

Energy Technology Data Exchange (ETDEWEB)

Sirikulrat, N., E-mail: scphi003@chiangmai.ac.th

2012-02-29

The current-voltage (I-V) relationship of aluminum doped zinc oxide thin film-antimony doped barium strontium titanate single heterojunction diodes was investigated. The linear I-V characteristics are similar to those of the PN junction diodes. The linear conduction at a low forward bias voltage as predicted by the space charge limited current theory and the trap free square law at a higher forward voltage are observed. The overall current density-voltage (J-V) characteristics of the diodes are found to be well described by the Power Series Equation J= N-Ary-Summation {sub m}C{sub m}V{sup m} where C{sub m} is the leakage constant at particular power m with the best fit for the power m found to be at the fourth and fifth orders for the forward and reverse bias respectively. - Highlights: Black-Right-Pointing-Pointer The n-n isotype heterojunction diodes of ceramic oxide semiconductors were prepared. Black-Right-Pointing-Pointer The current density-voltage (J-V) curves were analyzed using the Power Series (PS). Black-Right-Pointing-Pointer The J-V characteristics were found to be well described with PS at low order. Black-Right-Pointing-Pointer The thermionic emission and diode leakage currents were comparatively discussed.

Strontium-90 Error Discovered in Subcontract Laboratory Spreadsheet. Topical Report

International Nuclear Information System (INIS)

Brown, D.D.; Nagel, A.S.

1999-07-01

West Valley Demonstration Project health physicists and environment scientists discovered a series of errors in a subcontractor's spreadsheet being used to reduce data as part of their strontium-90 analytical process

Electrical properties and thermal expansion of strontium aluminates

Energy Technology Data Exchange (ETDEWEB)

Zakharchuk, K.V. [Department of Materials and Ceramic Engineering, CICECO, University of Aveiro, 3810-193 Aveiro (Portugal); Yaremchenko, A.A., E-mail: ayaremchenko@ua.pt [Department of Materials and Ceramic Engineering, CICECO, University of Aveiro, 3810-193 Aveiro (Portugal); Fagg, D.P. [TEMA-NRD, Mechanical Engineering Department, University of Aveiro, 3810-193 Aveiro (Portugal)

2014-11-15

Highlights: • Sr{sub 3}Al{sub 2}O{sub 6}, SrAl{sub 2}O{sub 4} and Sr{sub 4}Al{sub 14}O{sub 25} ceramics are semiconductors. • Electrical conductivity is as low as 10{sup −6}−4×10{sup −5} S/cm at 1273 K in dry air. • SrAl{sub 2}O{sub 4} is a mixed conductor with predominant ionic conductivity. • Sr{sub 3}Al{sub 2}O{sub 6} shows significant contribution of protonic transport in wet atmospheres. • Average TECs vary in the range (8.5–11.1)×10{sup −6} K{sup −1} and are p(O{sub 2})-independent. - Abstract: Strontium aluminate ceramics, including Sr{sub 3}Al{sub 2}O{sub 6}, SrAl{sub 2}O{sub 4} and Sr{sub 4}Al{sub 14}O{sub 25}, synthesized by glycine–nitrate combustion and sintered at 1773 K in air, were characterized by thermal analysis, dilatometry and electrical measurements in controlled atmospheres. All studied strontium aluminates are semiconductors with electrical conductivities as low as 10{sup −6}−4×10{sup −5} S/cm at 1273 K in dry air. Electrical measurements in controlled atmospheres in combination with ion transference number determination demonstrated that SrAl{sub 2}O{sub 4} is a mixed conductor with predominant ionic conductivity and increasing n-type and p-type electronic contributions under highly reducing and oxidizing conditions, respectively. While the behavior of electrical conductivity of Sr{sub 3}Al{sub 2}O{sub 6} in dry atmospheres was qualitatively similar to that of SrAl{sub 2}O{sub 4}, a significant increase of conductivity in wet atmospheres was attributed to a protonic contribution to electrical conduction, in correlation with thermogravimetric data and the tendency of this material to form a hydrogarnet at low temperatures. The average thermal expansion coefficients of strontium aluminates, (8.5–11.1)×10{sup −6} K{sup −1} at 333–1373 K, increase with increasing strontium content in the sequence Sr{sub 4}Al{sub 14}O{sub 25} < SrAl{sub 2}O{sub 4} < Sr{sub 3}Al{sub 2}O{sub 6} and are essentially

The reduction in inflammation and impairment in wound healing by using strontium chloride hexahydrate.

Science.gov (United States)

Berksoy Hayta, Sibel; Durmuş, Kasim; Altuntaş, Emine Elif; Yildiz, Esin; Hisarciklıo, Mehmet; Akyol, Melih

2018-03-01

Numerous growth factors, cytokine, mitogen and chemotactic factors are involved in wound healing. Even though inflammation is important for the stimulation of proliferative phase, excessive inflammation also causes impairment in wound healing. Strontium salts suppress keratinocyte-induced TNF-alpha and interleukin-1 and interleukin-6 in in vitro cultures. This study was conducted to determine the effects of administration of topical strontium chloride hexahydrate on wound healing through TNF-alpha and TGF-beta in surgical wound healing model of in-vivo rat skin. Twenty-four rats were used in the study. After approximately 2 cm cutaneous-subcutaneous incision was horizontally carried out on the mid-neckline of the rats, the incision was again closed using 2.0 vicryl. The rats were assigned into three groups including eight rats in each group. Placebo emollient ointment and also the ointments, which were containing 5% and 10% strontium chloride hexahydrate and were prepared at the same base with placebo ointment, were administered to the groups by a blind executor twice a day for a week. At the end of seventh day, the rats were sacrificed and cutaneous and subcutaneous tissue of their wound site was resected for histopathological examination. Scoring of histopathological wound healing and scoring of tissue TNF-alpha and TGF-beta level with immunohistochemical staining were performed. The groups, to which both 5% and 10% strontium chloride hexahydrate was administered, had lower immunohistochemical TNF-alpha levels and histopathological wound scores compared to controls, which was statistically significant (p < 0.05). Strontium chloride hexahydrate can lead to impairment in wound healing by suppressing inflammation through TNF-alpha.

Stable and strontium isotopic records of molluscan shells, lower jurassic, Cuenca Neuquina, southwestern Mendoza, Argentina

International Nuclear Information System (INIS)

Cagnoni, M.C.; Valencio, S.A.; Ramos, A.M; Riccardi, A.C; Panarello, H.O

2001-01-01

The strontium, carbon and oxygen isotopic signal of the past oceans is accurately recorded by authigenic marine minerals such as carbonates, sulfates and phosphates. The variation of these isotope ratios through the geological time is used as a tool in correlating and dating marine sedimentary rocks. Many works have been done concerning to the changes in carbon, oxygen and strontium isotope ratios of different marine successions in the world. These allow the construction of curves of secular variations of the isotope signals with geological time (Jones et al., 1994a, 1994b; Veizer et al., 1999; Jacobsen and Kaufman, 1999). This work presents strontium, carbon and oxygen isotope ratios of Early Jurassic biogenic marine carbonates of Cuenca Neuquina in southwestern Mendoza (au)

Determination of strontium and lead isotope ratios of grains using high resolution inductively coupled plasma mass spectrometer with single collector

International Nuclear Information System (INIS)

Shinozaki, Miyuki; Ariyama, Kaoru; Kawasaki, Akira; Hirata, Takafumi

2010-01-01

A method for determining strontium and lead isotope ratios of grains was developed. The samples investigated in this study were rice, barley and wheat. The samples were digested with nitric acid and hydrogen peroxide, and heated in a heating block. Strontium and lead were separated from the matrix by adding an acid digested solution into a column packed with Sr resin, which has selectivity for the absorption of strontium and lead. Strontium and lead isotope ratios were determined using a high-resolution inductively coupled plasma mass spectrometer (HR-ICP-MS) with a single collector. The intraday relative standard deviations of 87 Sr/ 86 Sr and lead isotope ratios ( 204 Pb/ 206 Pb, 207 Pb/ 206 Pb, 208 Pb/ 206 Pb) by HR-ICP-MS measurements were < 0.06% and around 0.1%, respectively. This method enabled us to determine strontium and lead isotope ratios in two days. (author)

Sintered bentonite ceramics for the immobilization of cesium- and strontium-bearing radioactive waste

Science.gov (United States)

Ortega, Luis Humberto

The Advanced Fuel Cycle Initiative (AFCI) is a Department of Energy (DOE) program, that has been investigating technologies to improve fuel cycle sustainability and proliferation resistance. One of the program's goals is to reduce the amount of radioactive waste requiring repository disposal. Cesium and strontium are two primary heat sources during the first 300 years of spent nuclear fuel's decay, specifically isotopes Cs-137 and Sr-90. Removal of these isotopes from spent nuclear fuel will reduce the activity of the bulk spent fuel, reducing the heat given off by the waste. Once the cesium and strontium are separated from the bulk of the spent nuclear fuel, the isotopes must be immobilized. This study is focused on a method to immobilize a cesium- and strontium-bearing radioactive liquid waste stream. While there are various schemes to remove these isotopes from spent fuel, this study has focused on a nitric acid based liquid waste. The waste liquid was mixed with the bentonite, dried then sintered. To be effective sintering temperatures from 1100 to 1200°C were required, and waste concentrations must be at least 25 wt%. The product is a leach resistant ceramic solid with the waste elements embedded within alumino-silicates and a silicon rich phase. The cesium is primarily incorporated into pollucite and the strontium into a monoclinic feldspar. The simulated waste was prepared from nitrate salts of stable ions. These ions were limited to cesium, strontium, barium and rubidium. Barium and rubidium will be co-extracted during separation due to similar chemical properties to cesium and strontium. The waste liquid was added to the bentonite clay incrementally with drying steps between each addition. The dry powder was pressed and then sintered at various temperatures. The maximum loading tested is 32 wt. percent waste, which refers to 13.9 wt. percent cesium, 12.2 wt. percent barium, 4.1 wt. percent strontium, and 2.0 wt. percent rubidium. Lower loadings of waste

Optical lattice clock with strontium atoms; Horloge a reseau optique a atomes de strontium

Energy Technology Data Exchange (ETDEWEB)

Baillard, X.; Le Targat, R.; Fouche, M.; Brusch, A.; Westergaard, Ph.G.; Lecallier, A.; Lodewyck, J.; Lemonde, P. [Observatoire de Paris, LNE-SYRTE, Systemes de Reference Temps Espace, 75 (France)

2009-07-01

Optical lattice clocks, which were first imagined in 2000, should allow one to achieve unprecedented performances in the domain of atomic clocks. We present here the Strontium lattice clock, developed at LNE-SYRTE. The principle, in particular trapping atoms in the Lamb-Dicke regime and the notion of magic wavelength, is first explained. We then present the results obtained for the {sup 87}Sr isotope, with a frequency accuracy of 2,6.10{sup -15}, and the {sup 88}Sr isotope, with. which we perform the first frequency measurement of an optical lattice clock with bosonic atoms. (authors)

Effective improvement of interface modified strontium titanate based solid oxide fuel cell anodes by infiltration with nano-sized palladium and gadolinium-doped cerium oxide

DEFF Research Database (Denmark)

Abdul Jabbar, Mohammed Hussain; Høgh, Jens Valdemar Thorvald; Zhang, Wei

2013-01-01

The development of low temperature solid oxide fuel cell (SOFC) anodes by infiltration of Pd/Gd-doped cerium oxide (CGO) electrocatalysts in Nb-doped SrTiO3 (STN) backbones has been investigated. Modification of the electrode/electrolyte interface by thin layer of spin-coated CGO (400-500 nm) con...

Role of aluminum on the physical and spectroscopic properties of chromium-doped strontium alumino borate glasses

Science.gov (United States)

Ahmed, Mohamed Raheem; Sekhar, K. Chandra; Hameed, Abdul; Chary, M. Narasimha; Shareefuddin, Md

2018-03-01

The glass samples were prepared in accordance with the formula: (30-x)SrO-xAl2O3-69.8B2O3-0.2Cr2O3 (0 ≤x ≤ 15 mol %) by melt quenching method. The absence of Bragg’s peaks confirmed the amorphous nature of the prepared glass samples. It was observed that the molar volume was increasing while the density is decreasing with increasing of Al2O3 content. Optical absorption study was performed to evaluate the optical bandgap, oxygen packing density, ionic packing density and Urbach energies. The Racah parameters (B and C) and Dq/B ratio have been calculated. Fourier transform infrared (FTIR) spectra recorded in the region from 400-1600 cm-1 at room-temperature (RT) confirmed the formation of BO3, BO4 and AlO4 groups upon the addition of strontium oxide as modifier. The Raman spectra of all the glasses recorded over continuous spectral range 200-1600 cm-1 exhibited different spectral bands. The EPR spectra recorded at 9.7 GHz (X-band frequency) have four resonance signals. The signal at g ≈ 5.33 is due to Cr3+ ion sites of rhombic symmetry and signal at g ≈ 1.97 is due to contribution from Cr3+ and Cr5+ ion pairs.

Study of the FeSO4 effectivity as a carrier for Sr 90 separation from liquid strontium waste

International Nuclear Information System (INIS)

Djoko Sardjono.

1978-01-01

The effectiveness of FeSO 4 as a carrier for removing Sr 90 from the strontium liquid waste is studied. This research is concerned with the study of the capacity of FeSO 4 as a carrier for removing Sr 90 from the strontium liquid waste. The method being used in the experiment is an application of the coprecipitation method to reduce the activity of the strontium liquid waste to a certain activity that is safe enough to be discharged in the environment. (author)

Chemical composition and microstructure of magnetically melt-textured Bi2Sr2Ca0.8Dy0.2Cu2O8-y

International Nuclear Information System (INIS)

Stassen, S.; Rulmont, A.; Krekels, T.; Ausloos, M.; Cloots, R.

1996-01-01

Dysprosium-doped Bi-based 2212 materials have been synthesized in the presence of a magnetic field, applied perpendicularly to the lateral face of a cylinder, by a melt-textured growth process. Thick (well oriented) layers of different chemical composition have been observed. A dysprosium-doped 2212 phase (the expected D phase) and a dysprosium-free bismuth-rich and strontium-deficient 2212 phase have been found. It is argued that the latter is a so-called M phase. Other impurity phases have been observed, connected with both 2212-type layers. A novel aspect of this work is the calcium solubility at the strontium site in the 2201 structure, and inversely the strontium solubility at the calcium site in the 8250 structure. (orig.)

Comment on: 'The strontium isotopic composition of seawater and seawater-oceanic crust interaction' by E.T.C. Spooner

International Nuclear Information System (INIS)

Brass, G.W.; Turekian, K.L.

1977-01-01

Various processes have been proposed as the source of strontium to the oceans but there is no evidence to support the mechanism of release of relatively unradiogenic strontium from deep dea basalts to sea-water. (B.D.)

Effect of strontium addition and chitosan concentration variation on cytotoxicity of chitosan-alginate-carbonate apatite based bone scaffold

Science.gov (United States)

Perkasa, Rilis Eka; Umniati, B. Sri; Sunendar, Bambang

2017-09-01

Bone scaffold is one of the most important component in bone tissue engineering. Basically, bone scaffold is a biocompatible structure designed to replace broken bone tissue temporarily. Unlike conventional bone replacements, an advanced bone scaffold should be bioactive (e.g: supporting bone growth) and biodegradable as new bone tissue grow, while retain its mechanical properties similarity with bone. It is also possible to add more bioactive substrates to bone scaffold to further support its performance. One of the substrate is strontium, an element that could improve the ability of the bone to repair itself. However, it must be noted that excessive consumption of strontium could lead to toxicity and diseases, such as osteomalacia and hypocalcemia. This research aimed to investigate the effect of strontium addition to the cytotoxic property of chitosan-alginate-carbonate apatite bone scaffold. The amount of strontium added to the bone scaffold was 5% molar of the carbonate apatite content. As a control, bone scaffold without stronsium (0% molar) were also made. The effect of chitosan concentration variation on the cytotoxicity were also observed, where the concentration varies on 1% and 3% w/v of chitosan solution. The results showed an optimum result on bone scaffold sample with 5% molar of strontium and 3% chitosan, where 87.67% cells in the performed MTS-Assay cytotoxicity testing survived. This showed that the use of up to 5% molar addition of strontium and 3% chitosan could enhance the survivability of the cell.

Quaternary system of lithium, potassium, calcium and strontium fluorides

International Nuclear Information System (INIS)

Garkushin, I.K.; Voronin, K.Yu.; Dibirov, M.A.; Miftakhov, T.T.

1996-01-01

Four-component system of lithium, potassium, calcium and strontium fluorides is studied by differential thermal analysis. A low-melting eutectic composition is revealed, specific fusion heat of the composition is experimentally determined, its thermal properties are calculated. 8 refs., 5 figs., 1 tab

Radiochemical determination of strontium-90 and cesium-137 in waters of the Pacific Ocean and its neighboring seas

International Nuclear Information System (INIS)

Borisenko, G.S.; Kandinskii, P.A.; Gedeonov, L.I.; Ivanova, L.M.; Petrov, A.A.

1987-01-01

Depending on the salinity of the water, two versions of strontium-90 and cesium-137 concentration from water samples are presented. Cesium-137 was concentrated by precipitating sparingly soluble mixed hexacyanoferrates (II), and strontium-90 by precipitating carbonates together with calcium. A scheme has been given for radiochemical analysis of the concentrates. Strontium-90 and cesium-137 contents in the waters of the Pacific Ocean and its neighboring seas have been determined by the radiochemical method described. The levels of radionuclide content in the water and atmospheric precipitations have been shown to be inter-related. Strontium-90 and cesium-137 contents in the surface water of the northwestern Pacific were found to be much lower in 1980 than in the early seventies. The area of technogenic radioactive pollution was found to persist in the region of the Columbia mouth into the Pacific Ocean

The effects of strontium on bone mineral: A review on current knowledge and microanalytical approaches.

Science.gov (United States)

Querido, William; Rossi, Andre L; Farina, Marcos

2016-01-01

The interest in effects of strontium (Sr) on bone has greatly increased in the last decade due to the development of the promising drug strontium ranelate. This drug is used for treating osteoporosis, a major bone disease affecting hundreds of millions of people worldwide, especially postmenopausal women. The novelty of strontium ranelate compared to other treatments for osteoporosis is its unique effect on bone: it simultaneously promotes bone formation by osteoblasts and inhibits bone resorption by osteoclasts. Besides affecting bone cells, treatment with strontium ranelate also has a direct effect on the mineralized bone matrix. Due to the chemical similarities between Sr and Ca, a topic that has long been of particular interest is the incorporation of Sr into bones replacing Ca from the mineral phase, which is composed by carbonated hydroxyapatite nanocrystals. Several groups have analyzed the mineral produced during treatment; however, most analysis were done with relatively large samples containing numerous nanocrystals, resulting thus on data that represents an average of many crystalline domains. The nanoscale analysis of the bone apatite crystals containing Sr has only been described in a few studies. In this study, we review the current knowledge on the effects of Sr on bone mineral and discuss the methodological approaches that have been used in the field. In particular, we focus on the great potential that advanced microscopy and microanalytical techniques may have on the detailed analysis of the nanostructure and composition of bone apatite nanocrystals produced during treatment with strontium ranelate. Copyright © 2015. Published by Elsevier Ltd.

System of lithium, sodium, and strontium bromides

International Nuclear Information System (INIS)

Litvinova, G.N.; Yagub'yan, E.S.; Bukhalova, G.A.

1988-01-01

The visual-polythermal and partially differential thermal methods of analysis have been applied to investigate the meltability diagram of the Li 2 Br 2 -Na 2 Br 2 -SrBr 2 ternary system. Three fields of crystallization belonging to strontium bromide, to the compound LiSr 2 Br 5 and solid solutions of lithium and sodium bromides are found. Two points complying with nonvariant equilibria are discovered

The effect of the host composition on the lifetime decay properties of barium/strontium aluminates compounds

International Nuclear Information System (INIS)

Rezende, Marcos V. dos S.; Andrade, A. B.; Valerio, Mário E. G.; Montes, Paulo J. R

2014-01-01

This paper reports the influence of the structural change on the luminescence of Eu-doped barium/strontium aluminates when excited with monochromatic X-rays (also known as X-ray excited optical luminescence—XEOL). Ba 1−x Sr x Al 2 O 4 samples, with 0  2+ and Eu 3+ transitions, although no Eu 2+ was observed in the X-ray absorption spectra. The XEOL intensities while the sample is under irradiation decreased as a function of the irradiation time, indicating the buildup of radiation damage. The saturation level of the XEOL is directly correlated to the amount of damages induced by the irradiation and the sample composition. The Ba-rich samples are the ones with higher XEOL yield. X-ray induced long lasting phosphorescence (LLP) was also observed for all samples and it was found that the duration of the phosphorescence emission also depends on the sample composition. In Sr-rich samples, the LLP has a slower decay time constant than in Ba-rich samples. A model of the radiation induced luminescence is presented and all these features are discussed in terms of the energetic costs and the type of defects generated in the sample

Strontium PVC-membrane sensor based on 2-[(2-mercaptophenylimino)methyl]phenol

Energy Technology Data Exchange (ETDEWEB)

Zamani, Hassan Ali [Young Researchers Club, Quchan branch, Islamic Azad University, Quchan (Iran, Islamic Republic of)], E-mail: haszamani@yahoo.com; Ganjali, Mohammad Reza; Norouzi, Parviz [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Endocrine and Metabolism Research Center, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Adib, Mahdi [Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of)

2008-01-10

The 2-[(2-mercaptophenylimino)methyl]phenol (MPMP) was used as an excellent ionophore in the construction of a Sr{sup 2+} PVC-based membrane sensor. The best performance was obtained with a membrane composition of 30% poly(vinyl chloride), 62% nitrobenzen (NB), 5.5% MPMP and 2.5% sodium tetraphenyl borate (NaTBP). This sensor demonstrates a good selectivity and sensitivity towards the strontium ion for many cations, including alkali, alkaline earth, transition and heavy metal ions. The sensor revealed a great enhancement in selectivity coefficients for strontium ions in comparison with the previously reported strontium sensors. The proposed sensor exhibits a Nernstian behavior (with a slope of 29.6 {+-} 0.3 mV per decade) for the concentration range of (1.0 x 10{sup -6}-1.0 x 10{sup -1} M) with a detection limit of 5.5 x 10{sup -7} M (48.2 ng/mL). It illustrates a relatively fast response time in the whole concentration range (< 10 s) and it can be used for at least 10 weeks in a pH range of 2.8-9.6. The developed sensor was successfully used as an indicator electrode in the Sr(II) titration with EDTA and the Sr{sup 2+} ion recovery from binary mixtures.

Effect of K-fertilization, liming and placement on crop uptake of cesium and strontium

International Nuclear Information System (INIS)

Haak, E.

1985-01-01

remedial measures to reduce crop uptake of cesium and strontium under Swedish field conditions have been investigated in micro plot experiments. For cesium the effect of K-fertilization was studied on three soils with oats, peas and mustard and, in combination with placement, on two other soils with wheat, barley and rape. For strontium the effect of liming was studied on three soils with oats, barley and peas and, in combination with placement, on two other soils with wheat, oats, barley and peas. In this paper results are summarized for the grain products. Deep placement of nuclides in combination with K-fertilization and liming reduced the crop uptake of cesium and strontium by a factor of 10 and 4, respectively. On the basis of the experimental results, the practical advantages of K-fertilization and liming, as well as deep ploughing of surface contaminated land are discussed

Rubidium-strontium and uranium-lead isotopic age studies

International Nuclear Information System (INIS)

Loveridge, W.D.

1980-01-01

Rubidium-strontium whole rock isochron ages and initial 87 Sr/ 86 Sr ratios and uranium-lead ages on zircon from suites of samples selected from localities across Canada are presented. Descriptions of the geological probelms and interpretations of the measured ages are included. Laboratory age determination methods and techniques are described or referenced. (auth)

Structure and thermodynamic properties of molten strontium chloride

International Nuclear Information System (INIS)

Pastore, G.; Ballone, P.; Tosi, M.P.; Trieste Univ.

1985-05-01

Self-consistent calculations of pair distribution functions and thermodynamic properties are presented for a pair-potentials model of molten strontium chloride. The calculations extend to a strongly asymmetric ionic liquid an earlier assessment of bridge diagrams in a modified hypernetted chain approach to the liquid structure of alkali halides. Good agreement is found with computer simulation data obtained by de Leeuw with the same set of pair potentials, showing that the present approach incorporates genuine general features of liquid structure theory for multicomponent liquids with strong relative ordering of the component species. It is further shown that the strong correlations between the divalent cations, both in the model and in real molten strontium chloride, can be approximately reproduced on the basis of a simple one-component-plasma model, provided that dielectric screening is allowed for in the real liquid. This allows us to tentatively attribute the significant level of disagreement between a pair potentials model of this liquid and the neutron diffraction data of McGreevy and Mitchell to many-body distortions of the electronic shells of the ions. (author)

Preparation and use of polymeric materials containing hydrophobic anions and plasticizers for separation of cesium and strontium

International Nuclear Information System (INIS)

Abney, K.D.; Kinkead, S.A.; Mason, C.F.V.; Rais, J.

1997-01-01

Preparation and use is described for polymeric materials containing hydrophobic anions and plasticizers for extraction of cesium and strontium. The use of polymeric materials containing plasticizers which are solvents for hydrophobic anions such as derivatives of cobalt dicarbollide or tetraphenylborate which are capable of extracting cesium and strontium ions from aqueous solutions in contact with the polymeric materials, is described. The polymeric material may also include a synergistic agent for a given ion like polyethylene glycol or a crown ether, for removal of radioactive isotopes of cesium and strontium from solutions of diverse composition and, in particular, for solutions containing large excess of sodium nitrate

Strontium 90 and cesium 137 content in the daily diet of two groups of people in Plovdiv

International Nuclear Information System (INIS)

Babakova, I.; Trendafilov, I.; Todorov, D.

1975-01-01

The contents of strontium 90 and cesium 137 in the daily diet of children, 7-11 years old, and teenagers, 14-18 years old, living under boarding house conditions is determined. The daily strontium 90 intake in the organism of children and teenagers amounts to 9,78 pCi, respectively 17,96 pCi and the daily intake of cesium 137 - to 13,21 pCi, respectively 21,33 pCi. The bigger part of the strontium 90 and cesium 137 intake comes from the bread, accounting for 4,85 pCi stroncium 90 and 5,08 to 7,0 pCi cesium 137. (author)

Radiation protection data sheets for the use of Strontium 90-Yttrium 90 in unsealed sources

International Nuclear Information System (INIS)

Anon.

1993-01-01

This radiation protection data sheet is intended for supervisors and staff in the different medical, hospital, pharmaceutical, university and industrial laboratories and departments where Strontium 90-Yttrium 90 is handled, and also for all those involved in risk prevention in this field. It provides essential data on radiation protection measures during the use of Strontium 90-Yttrium 90 in unsealed sources: physical characteristics, risk assessment, administrative procedures, recommendations, regulations and bibliography

Strontium-90 and cesium-137 in sea water (from Jul 1984 to Sep 1984)

International Nuclear Information System (INIS)

1984-01-01

Monitoring results are presented on strontium-90 and cesium-137 contents in sea water of 11 sampling points all over Japan from Hokkaido to Okinawa coast. Sampling points were selected by the criterion that the effect of terrestrial fresh water and atmospheric precipitation was expected to be ignorable. Sample collection was carried out in the Period from July to September, 1984. With a special care for prevention of any contamination. The collected sea water samples were acidified immediately and they were served for radiochemical separation and purification of strontium-90 and cesium-137. Radiation counting was made for yttrium-90 hydroxide sample and cesium chloroplatinate sample with a low background beta counter normally for 60 minutes. As for strontium-90 contents in sea water, they were ranged from 0.07 +- 0.010 pCi/l (Mutsu Bay, Aomori) to 0.11 +- 0.012 pCi/l (Off Niigata Port, Niigata) and the average value was 0.09 pCi/l. As for cesium-137 contents, they were ranged from 0.08 +- 0.011 pCi/l (Ise Bay, Aichi) to 0.14 +- 0.012 pCi/l (Yamaguchi Bay, Yamaguchi) and the average value was 0.106 pCi/l. It is clarified that no abnormal values were determined for strontium-90 or cesium-137 contents in coastal sea water around Japan from a fallout origin. (Takagi, S.)

Human telomeric G-quadruplex formation and highly selective fluorescence detection of toxic strontium ions.

Science.gov (United States)

Qu, Konggang; Zhao, Chuanqi; Ren, Jinsong; Qu, Xiaogang

2012-03-01

Strontium ions play important roles in biological systems. The inhalation of strontium can cause severe respiratory difficulties, anaphylactic reaction and extreme tachycardia. Strontium can replace calcium in organisms, inhibit normal calcium absorption and induce strontium "rickets" in childhood. Thus, the development of sensitive and selective methods for the determination of trace amounts of Sr(2+) in aqueous media is of considerable importance for environmental and human health protection. A number of methodologies, such as X-ray energy dispersive spectrometry, inductively coupled argon plasma atomic emission spectroscopy (ICP-AES), atomic absorption spectrometry (AAS) and instrumental thermal neutron activation analysis, have been reported. However, these methods are somewhat complex, costly, time consuming and, especially, need special instruments. Thus, the design of convenient and inexpensive approaches for the sensitive and selective detection of Sr(2+) with rapid, easy manipulation is in ever-increasing demand. To the best of our knowledge, using DNA conformational change to detect Sr(2+) has not yet been reported. Herein we utilized thiazole orange (TO) as a signal reporter to devise a simple Sr(2+) detection assay based on Sr(2+) induced human telomeric DNA conformational change in the presence of SWNTs. The limit of detection is 10 nM Sr(2+) (0.87 μg L(-1)), far below 4 mg L(-1), the U.S. Federal threshold in drinking water defined by the U.S. EPA.

Sol-hydrothermal synthesis and optical properties of Eu3+, Tb(3+)-codoped one-dimensional strontium germanate full color nano-phosphors.

Science.gov (United States)

Lin, Liangwu; Sun, Xinyuan; Jiang, Yao; He, Yuehui

2013-12-21

Novel near-UV and blue excited Eu(3+), Tb(3+)-codoped one dimensional strontium germanate full-color nano-phosphors have been successfully synthesized by a simple sol-hydrothermal method. The morphologies, internal structures, chemical constitution and optical properties of the resulting samples were characterized using FE-SEM, TEM, HRTEM, EDS, XRD, FTIR, XPS, PL and PLE spectroscopy and luminescence decay curves. The results suggested that the obtained Eu(3+), Tb(3+)-codoped strontium germanate nanowires are single crystal nanowires with a diameter ranging from 10 to 80 nm, average diameter of around 30 nm and the length ranging from tens to hundreds micrometers. The results of PL and PLE spectra indicated that the Eu(3+), Tb(3+)-codoped single crystal strontium germanate nanowires showed an intensive blue, blue-green, green, orange and red or green, orange and red light emission under excitation at 350-380 nm and 485 nm, respectively, which may attributed to the coexistent Eu(3+), Eu(2+) and Tb(3+) ions, and the defects located in the strontium germanate nanowires. A possible mechanism of energy transfer among the host, Eu(3+) and Tb(3+) ions was proposed. White-emission can be realized in a single-phase strontium germanate nanowire host by codoping with Tb(3+) and Eu(3+) ions. The Eu(3+), Tb(3+)-codoped one-dimensional strontium germanate full-color nano-phosphors have superior stability under electron bombardment. Because of their strong PL intensity, good CIE chromaticity and stability, the novel 1D strontium germanate full-color nano-phosphors have potential applications in W-LEDs.

Modified cermet fuel electrodes for solid oxide electrochemical cells

Science.gov (United States)

Ruka, Roswell J.; Spengler, Charles J.

1991-01-01

An exterior porous electrode (10), bonded to a solid oxygen ion conducting electrolyte (13) which is in contact with an interior electrode (14), contains coarse metal particles (12) of nickel and/or cobalt, having diameters from 3 micrometers to 35 micrometers, where the coarse particles are coated with a separate, porous, multiphase layer (17) containing fine metal particles of nickel and/or cobalt (18), having diameters from 0.05 micrometers to 1.75 micrometers and conductive oxide (19) selected from cerium oxide, doped cerium oxide, strontium titanate, doped strontium titanate and mixtures thereof.

Reverse micellar synthesis, structural characterization and dielectric properties of Sr-doped BaZrO_3 nanoparticles

International Nuclear Information System (INIS)

Ahmad, Tokeer; Ubaidullah, Mohd; Shahazad, Mohd; Kumar, Dinesh; Al-Hartomy, Omar A.

2017-01-01

Sr-doped BaZrO_3 nanoparticles with strontium content varying from 5 to 20 mol % were successfully synthesized by reverse micellar method at 900 °C for the first time. Systematic studies have been carried out to establish the structural and electrical properties of the as prepared nanoparticles. These nanoparticles were characterized using powder X-ray diffraction, transmission electron microscopy, BET surface area and dielectric measurements. X-ray diffraction analysis showed the formation of monophasic and highly crystalline nanoparticles which could be indexed in cubic BaZrO_3 with contraction of lattice on strontium substitution. A monotonic shift of diffraction pattern towards higher angel confirms the formation of solid solutions of Ba_1_−_xSr_xZrO_3 (0.05 ≤ x ≤ 0.20) which was corroborating well with lattice parameter studies. Transmission electron microscopic studies showed the formation of cubic, spherical and hexagonal nanoparticles with an average grain size of 40–65 nm. Energy dispersive X-ray spectroscopic studies confirmed the presence of dopant (Sr"2"+) in the BaZrO_3 matrix and estimated chemical species corroborate well with the loaded composition. Specific surface area of the solid solution comes out to be in the range of 104–244 m"2 g"-"1. Smallest particle of size 40 nm shows highest surface area 244 m"2 g"-"1 for 20 mol% Sr-doped BaZrO_3. Dielectric and impedance studies were also carried out as a function of frequency and temperature to explore the electrical properties of Sr-doped BaZrO_3. The dielectric constant of Ba_1_−_xSr_xZrO_3 (0.05 ≤ x ≤ 0.20) was found to be in the range of 13–25 for x = 0.05 to x = 0.20 with nearly similar dielectric loss of the order of 0.02. The conductance increases linearly with increase in frequency at room temperature, however the impedance has an inverse effect. - Highlights: • Monophasic nanocrystalline Ba_1_−_xSr_xZrO_3 at low dopant concentration using reverse micelles for the first

Strontium-90 and cesium-137 in fresh water

International Nuclear Information System (INIS)

1978-01-01

Japan Chemical Analysis Center has analysed the strontium-90 and Cesium-137 contents in fresh water from 7 prefectures in Japan by the commission of Science and Technology Agency of Japanese Government. The method described in ''Radioactivity Survey Data in Japan No. 43 (NIRS-RSD-43, 1977) was applied to the analysis of these two radionuclides in samples. (author)

Investigation of new materials for SOFC applications; Untersuchungen zum Einsatz neuer Werkstoffe fuer SOFC-Anwendungen

Energy Technology Data Exchange (ETDEWEB)

Wackerl, J.

2007-05-04

Fuel cells based on solid oxides ('SOFC') are excellent alternative devices for power generation, when they are operated at high temperature, e.g. above 600 C. Having only fixed parts for the power generating part of the device is only one advantage of the fuel cell. Due to their unique design, these devices offer a maximum of efficiency for energy conversion compared to conventional power generating systems, which are mainly based on turbines. One aim of this thesis is the examination of alternative electrolyte and cathode materials for the SOFC applications at reduced temperatures, which means in the temperature range between 600 C and 750 C. For the first main task, several materials from the oxygen ion conducting electrolytes were selected. Different strontium and magnesium doped lanthanum gallate (LSGM) materials with additional transition metal doping were selected and prepared via two different preparation methods. The optimum calcining conditions were determined using thermal analysis methods. The results of the structural analysis of the sintered electrolyte materials were used to select the most suitable electrolyte materials. As a result, LSGM and iron doped LSGM (LSGMF) were the most promising materials. Further investigations were carried out on LSGMF materials with different strontium content. The influence of chemical cation non-stoichiometry on the perovskite material was investigated. Therefore, measurements to gather information about the crystallographic structure, morphology, electrochemistry and electrical conductivity were carried out. For a selected sample, the correlations between single effects, such as the crystallographic structure, and the electrical properties are shown by combining the different analysis methods. It could be shown that both the electrochemistry and the crystallographic structure have a significant influence on the electrical conductivity of the LSGMF materials. The second aim of the thesis was the selection

Combining x-ray diffraction contrast tomography and mesoscale grain growth simulations in strontium titanate: An integrated approach for the investigation of microstructure evolution

DEFF Research Database (Denmark)

Syha, Melanie; Baürer, Michael; Rheinheimer, Wolfgang

2013-01-01

Motivated by the recently reported a growth anomaly in strontium titatate bulk samples1, the microstructure of bulk strontium titanate has been investigated by an integrated approach comprising conventional metallography, three dimensional X-ray diffraction contrast tomography (DCT)2, and the obs......Motivated by the recently reported a growth anomaly in strontium titatate bulk samples1, the microstructure of bulk strontium titanate has been investigated by an integrated approach comprising conventional metallography, three dimensional X-ray diffraction contrast tomography (DCT)2......, and the observation of pore shapes in combination with mesoscale grain growth simulations. The microstructural evolution in strontium titanate has been characterized alternating ex-situ annealing and high energy X-ray DCT measurements, resulting in three dimensional microstructure reconstructions which...

Laboratory scale stabilization of N-springs groundwater strontium-90 using phosphatic materials

International Nuclear Information System (INIS)

Moody, T.E.; Petersen, S.W.; Torne, E.G.; Vlcakova, J.; Higginbotham, J.F.

1996-09-01

This document presents the results of a laboratory study designed to evaluate the ability of phosphatic materials to sorb strontium-90 from soil and groundwater. This study was initiated to investigate the potential use of phosphatic materials as permeable geochemical barriers for groundwater contaminated with strontium-90. Groundwater discharges to the Columbia River create potential human food chain hazards; therefore, it is imperative to immobilize the contamination before it reaches the river. Phosphate materials have been proven by various researchers to be chemical compounds that combine with contaminant metals forming into insoluble metal-phosphate minerals. These minerals are stable and insoluble under normal soil conditions

Co-extraction of Strontium and Cesium by Dicyclohexano-18 Crown-6/25, 27-Bis(2- Propyloxy)Calix[4]-26, 28-Crown-6{sup ..}Cn-Octanol

Energy Technology Data Exchange (ETDEWEB)

Ye, W.L.; Wang, J.CH.; He, Q.G. [Institute of Nuclear and New Energy Technology, Tsinghua University, P.O. Box 1021, Beijing 102201 (China)

2009-06-15

The partitioning of {sup 90}Sr and {sup 137}Cs from high-level liquid waste(HLLW) is one of the important problems for the high-level waste volume reduction and the management of HLLW. The crown ether and calix-crown have the good extracting ability and selectivity to strontium and cesium respectively. Dicyclohexano-18Crown-6 (DCH18C-6) and 25, 27-Bis(2-propyloxy) Calix[4] -26, 28- Crown-6(IPR-C[4]C-6) were selected as extractants and n-octanol was selected as the common diluent to separate strontium and cesium from high-level liquid waste respectively in INET's Tsinghua University, China. But DCH18C- 6 and IPR-C[4]C-6 were used respectively in their processes to separate strontium and cesium. The strontium and cesium processes could be simplified if DCH18C-6 and IPR-C[4]C-6 processes are combined into one process to separate strontium and cesium together. In this paper, the co-extraction performance of strontium and cesium from nitric acid medium was studied by DCH18C-6 /IPR-C[4]C-6 and n-octanol as an diluent. Effects of extractant concentration, nitric concentration and temperature etc. on the extraction performance of strontium and cesium were studied. The results show that DCH18C-6 and IRP-C[4]C-6 in n-octanol has no synergistic extraction ability each other to strontium and cesium. Strontium and cesium were extracted independently by above two extractants. 0.1 mol/L DCH18C-6 and 0.025 mol/L /IPR-C[4]C-6 as extractants and n-octanol as a diluent were selected to separate strontium and cesium from HLLW. The cascade test in which was 10 stages for extraction, 2 stages for scrubbing and 8 stages for stripping was carried out on the miniature centrifugal contactor set. The results are the following: the removing ratios for strontium and cesium in the simulated HLLW were 98.93% and 99.93%, respectively; the stripping ratios of them were 99.80% and 99.79%, respectively. So the mixing extractants could be used to co-extract strontium and cesium from HLLW and

The determination of radioactive strontium in environmental samples by preferential ion exchange separation from calcium

International Nuclear Information System (INIS)

Fukushima, Hiroto; Nonaka, Nobuhiro; Honda, Tetsutaro; Kimura, Toshimasa; Higuchi, Hideo

1979-01-01

The determination of radioactive strontium in environmental samples involves a difficulty in the separation and purification of strontium from large amounts of calcium. The principal technique employed in this study is based on a cation exchange separation after preferential chelation of calcium over strontium by EDTA. The alkaline earth fraction separated from samples is dissolved in 1.2 M HCl and an equivalent amount of EDTA is added. The solution is passed through a Dowex 50W-X8 ion exchange column at a flow rate of 20 ml/min after the pH has been adjusted to 5.1. A fraction of calcium retained on the resin is eluted out with 1.8 l of 2 w/v% EDTA solution at pH 5.1. Then the strontium is eluted with 450 ml of 2 M HCl. The strontium carbonate is precipitated, and the chemical yield is determined. After standing for 14 days to reach the radioactive equilibrium of 90 Sr - 90 Y, the activity of 89 Sr + 90 Sr + 90 Y is measured. Then the activity of 90 Sr + 90 Y is measured by milking the 90 Y. The proposed procedure has been applied to sea water, soil and various ash samples of vegetables, seaweeds and daily foods. The results obtained are in good agreement with those by a classical fuming nitric acid precipitation method. The detection limits are 0.1 pCi/l for 10 l of sea water, 10 pCi/kg for 100 g of soil and 1 pCi/kg-fresh for 20 g ash samples, respectively. (author)

Determination of solubility isotherms of barium and strontium nitrates in the system acetic acid-water at 250 C

International Nuclear Information System (INIS)

Hubicki, W.; Piskorek, M.

1976-01-01

Investigastions of the solubility of barium and strontium nitrates were carried out in the system: acetic acid - water at 25 0 C. When one compares the isotherms of solubility of barium and strontium nitrates, one can observe that it is possible to separate the admixtures of barium from strontium nitrates as a result of fractional crystallization of these nitrates from actic acid solution at the temperatures lower than 31.3 0 C, i.e. below the temperature of transformation: Sr(NO 3 ) 2 . 4H 2 O reversible to Sr(NO 3 ) 2 + 4H 2 O for aqueous solution. (author)

Strontium content in otoliths of common fish species in the northern Baltic Sea

Energy Technology Data Exchange (ETDEWEB)

Lill, J-O.; Heselius, S-J. [Accelerator Laboratory, Turku PET Centre, Abo Akademi University, Turku (Finland); Himberg, M.; Hagerstand, H. [Cell Biology, Department of Biosciences, Abo Akademi University, Turku (Finland); Harju, L. [Analytical Chemistry, Department of Chemical Engineering, Abo Akademi University, Turku (Finland); Lindroos, A. [Geology and Mineralogy, Department of Natural Sciences, Abo Akademi University, Turku (Finland); Gunnelius, K.; Smâtt, J-H. [Physical Chemistry, Department of Natural Sciences, Abo Akademi University, Turku (Finland)

2013-07-01

Full text: The salinity of water in the northern Baltic Sea forms a gradient as it receives fresh water from several large rivers in the north and salty water by infrequent inflows of North Sea water in the south. The salinity of brackish water in the north-south direction (700 km) changes from about 3 to 7%. In an attempt to use the salinity gradient to study migration patterns, sagittae otoliths were collected from common fish species caught at different locations along the Finnish west coast. Otoliths from fishes caught in fresh-water lakes in Finland and Estonia were also included in the study for comparison. Part of the otoliths was grind and the powder was pressed to pellets which were irradiated in air with an ion beam from the Abo Akademi cyclotron and the emitted X-rays were measured. Other otoliths were embedded in epoxy and polished to reveal the ring structure. These prepared otoliths were irradiated with the ion beam to determine elemental profiles. Furthermore, XRD was applied to study the crystal structure and to identify the minerals in the otoliths. The strontium level of water is usually related to its salinity, and as the strontium ions are able to replace calcium ions in fish otoliths [1], the strontium content in fish otoliths from the same locations is expected to be very similar. However, the PIXE analyses revealed large differences in the strontium content between otoliths from different species of fish caught at the same locations. The strontium concentration in otoliths of perch and pike from the Aland Islands was about 1600 μg/g and of common whitefish 3600 μg/g. The strontium concentration in perch otoliths from the Oravais archipelago, about 400 km north of the Aland Islands, was 1400 μg/g. Corresponding concentration in otoliths of perch and pike caught in fresh-water lakes was 200 μg/g and of common whitefish from Saadjarve 400 μg/g and from Lake Inari 1000 μg/g. Otoliths of perch contained no detectable amounts of zinc (Iower

Strontium content in otoliths of common fish species in the northern Baltic Sea

International Nuclear Information System (INIS)

Lill, J-O.; Heselius, S-J.; Himberg, M.; Hagerstand, H.; Harju, L.; Lindroos, A.; Gunnelius, K.; Smâtt, J-H.

2013-01-01

Full text: The salinity of water in the northern Baltic Sea forms a gradient as it receives fresh water from several large rivers in the north and salty water by infrequent inflows of North Sea water in the south. The salinity of brackish water in the north-south direction (700 km) changes from about 3 to 7%. In an attempt to use the salinity gradient to study migration patterns, sagittae otoliths were collected from common fish species caught at different locations along the Finnish west coast. Otoliths from fishes caught in fresh-water lakes in Finland and Estonia were also included in the study for comparison. Part of the otoliths was grind and the powder was pressed to pellets which were irradiated in air with an ion beam from the Abo Akademi cyclotron and the emitted X-rays were measured. Other otoliths were embedded in epoxy and polished to reveal the ring structure. These prepared otoliths were irradiated with the ion beam to determine elemental profiles. Furthermore, XRD was applied to study the crystal structure and to identify the minerals in the otoliths. The strontium level of water is usually related to its salinity, and as the strontium ions are able to replace calcium ions in fish otoliths [1], the strontium content in fish otoliths from the same locations is expected to be very similar. However, the PIXE analyses revealed large differences in the strontium content between otoliths from different species of fish caught at the same locations. The strontium concentration in otoliths of perch and pike from the Aland Islands was about 1600 μg/g and of common whitefish 3600 μg/g. The strontium concentration in perch otoliths from the Oravais archipelago, about 400 km north of the Aland Islands, was 1400 μg/g. Corresponding concentration in otoliths of perch and pike caught in fresh-water lakes was 200 μg/g and of common whitefish from Saadjarve 400 μg/g and from Lake Inari 1000 μg/g. Otoliths of perch contained no detectable amounts of zinc (Iower

Polymorphism’s assessment of children’s candidate genes associated with low-level long-term exposure to strontium in drinking water

OpenAIRE

N.V. Zaitseva; O.V. Dolgilh; A.V. Krivtsov; K.G. Starkova; V.A. Luchnikova; O.A. Bubnov; E.A. Otavina; N.V. Bezruchenko; N.A. Vdovina

2015-01-01

A sequencing of the candidate genes of the pupils, exposed to strontium by the method of targeted resequencing has been performed. It is shown, that under conditions of increased revenues of strontium in drinking water the number of polymorphonuclear altered portions of candidate genes increases. As a result of the targeted resequencing in conditions of strontium exposure, the maximum polymorph modifications of the following genes are defined: sulfotransferase 1A1 (SULT1A1) and methylenetetra...

Isotopic composition of strontium in three basalt-andesite centers along the Lesser Antilles arc

Science.gov (United States)

Hedge, C.E.; Lewis, J.F.

1971-01-01

Si87/Sr86 ratios have been determined for lavas and py lastic rocks from three basalt-andesite centers along the Lesser Antilles arc-Mt. Misery on the island of St. Kitts, Soufriere on the island of St. Vincent, and Carriacou, an island of The Grenadines. The average Si87/Sr86 content of these rocks is 0.7038 for Mt. Misery, 0.7041 for Soufriere, and 0.7053 for Carriacou. All the Sr87/Sr86 values from each center are the same within analytical uncertainty (??0.0002). The constancy of strontium isotopic data within each center supports the hypothesis that basalts and andesites for each specific center investigated are generated from the same source - in agreement with petrographic and major- and minor-element data. Strontium isotopic compositions and elemental concentrations, particularly of strontium and nickel, indicate that this source was mantle peridotite and that the relationship between the respective basalts and andesites is probably fractional crystallization. ?? 1971 Springer-Verlag.

Organic destruction to enhance the separation of strontium in radioactive wastes

International Nuclear Information System (INIS)

Schmidt, A.J.; Elmore, M.R.; Orth, R.J.; Jones, E.O.; Zacher, A.H.; Hart, T.R.; Neuenschwander, G.G.; Poshusta, J.C.

1994-01-01

A low-temperature (300 C to 375 C) hydrothermal organic destruction process is being evaluated to help facilitate the removal of complexed radioactive species from bulk liquid components in hanford tank waste. The work focuses on hydrothermal processing to destroy organic compounds that contribute to waste safety issues and organic complexants that promote the solubility of radioactive constituents such as 90 Sr and 241 Am. For the studies discussed here, testing was conducted using a nonradioactive Hanford tank waste simulant. The relative destruction rates of a variety of organic compounds known to be present in Hanford tank waste were evaluated. In addition, the tendency for these organic compounds to complex strontium and the effect of hydrothermal treatment on strontium removal were investigated

Organic destruction to enhance the separation of strontium in radioactive wastes

International Nuclear Information System (INIS)

Schmidt, A.J.; Elmore, M.R.; Orth, R.J.; Jones, E.O.; Zacher, A.H.; Hart, T.R.; Neuenschwander, G.G.; Poshusta, J.C.

1994-10-01

A low-temperature (300 C to 375 C) hydrothermal organic destruction process is being evaluated to help facilitate the removal of complexed radioactive species from bulk liquid components in Hanford tank waste. The work focuses on hydrothermal processing to destroy organic compounds that contribute to waste safety issues and organic complexants that promote the solubility of radioactive constituents such as 9O Sr and 241 Am. For the studies discussed here, testing was conducted using a nonradioactive Hanford tank waste simulant. The relative destruction rates of a variety of organic compounds known to be present in Hanford tank waste were evaluated. In addition, the tendency for these organic compounds to complex strontium and the effect of hydrothermal treatment on strontium removal were investigated

Phenolic cation exchange resin material for recovery of cesium and strontium

Science.gov (United States)

Ebra, Martha A.; Wallace, Richard M.

1983-01-01

A phenolic cation exchange resin with a chelating group has been prepared by reacting resorcinol with iminodiacetic acid in the presence of formaldehyde at a molar ratio of about 1:1:6. The material is highly selective for the simultaneous recovery of both cesium and strontium from aqueous alkaline solutions, such as, aqueous alkaline nuclear waste solutions. The organic resins are condensation polymers of resorcinol and formaldehyde with attached chelating groups. The column performance of the resins compares favorably with that of commercially available resins for either cesium or strontium removal. By combining Cs.sup.+ and Sr.sup.2+ removal in the same bed, the resins allow significant reduction of the size and complexity of facilities for processing nuclear waste.

Strontium-90 and cesium-137 migration in trophic chain of cattle

International Nuclear Information System (INIS)

Zotov, V.G.; Sirotkin, A.N.; Isamov, N.N.

1983-01-01

Technique for determination of factors of radionuclide migration in cattle trophic chain, which can be used for forecasting probable contamination of food and cattle breeding products Under Uzbekistan conditions is suggested. It is shown that the factor of biological absorption (FBA) of strontiUm 90 by plants from grey desert soils is 3.7 times higher, than of cesium 137. Mentioned differences in soil-plants migration link are leveled and their FBA in food-milk, food-bone, food-mUscles links remain practically the same during radionuclide migration from food to milk and meat. During radionuclide migration in trophic chain of cattle in food-bone and food-muscles chains the concentration of strontium 90 in bone tissUe and cesium 137 in muscle tissue takes place