Thermoluminescence of cerium and terbium -doped calcium pyrophosphate

Energy Technology Data Exchange (ETDEWEB)

Roman L, J.; Cruz Z, E. [UNAM, Instituto de Ciencias Nucleares, Circuito Exterior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Lozano R, I. B.; Diaz G, J. A. I., E-mail: jesus.roman@nucleares.unam.mx [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria No. 694, 11500 Mexico D. F. (Mexico)

2015-10-15

The aim of this work is to report the thermoluminescence (Tl) response of Calcium Pyrophosphate phosphor doped with Cerium and Terbium impurities (Ca{sub 2}P{sub 2}O{sub 7}:Ce{sup 3+},Tb{sup 3+}). The phosphors were synthesized using the co-precipitation method and annealed at 900 degrees C by two hours for obtain the β phase. The intentional doping with Ce and Tb ions was 1 at.% and 0.1 at.%, whereas in the EDS results the concentration of impurities was 0.39 at.% and 0.05 at.%, respectively. The superficial morphology of phosphor is mainly composed by thin wafers of different size. All samples were exposed to gamma rays from {sup 60}Co in the Gammacell-200 irradiator. The Tl response of the phosphor was measured from Rt up to 350 degrees C and under nitrogen atmosphere in a Harshaw TLD 3500 reader. The glow curves of the Ca{sub 2}P{sub 2}O{sub 7}:Ce{sup 3+},Tb{sup 3+} powders showed a broad intense Tl peak centered at 165 degrees C and a shoulder at approximate 260 degrees C was observed. A linear Tl response in the range of absorbed dose of 0.2 to 10 Gy was obtained. Tl glow curves were analyzed using the initial rise (IR)and computerized glow curve deconvolution methods to evaluate the kinetics parameters such as activation energy (E), frequency factor (s) and kinetic order (b). (Author)

Compact all-fiber optical Faraday components using 65-wt%-terbium-doped fiber with a record Verdet constant of -32 rad/(Tm).

Science.gov (United States)

Sun, L; Jiang, S; Marciante, J R

2010-06-07

A compact all-fiber Faraday isolator and a Faraday mirror are demonstrated. At the core of each of these components is an all-fiber Faraday rotator made of a 4-cm-long, 65-wt%-terbium-doped silicate fiber. The effective Verdet constant of the terbium-doped fiber is measured to be -32 rad/(Tm), which is 27 x larger than that of silica fiber. This effective Verdet constant is the largest value measured to date in any fiber and is 83% of the Verdet constant of commercially available crystal used in bulk optics-based isolators. Combining the all-fiber Faraday rotator with fiber polarizers results in a fully fusion spliced all-fiber isolator whose isolation is measured to be 19 dB. Combining the all-fiber Faraday rotator with a fiber Bragg grating results in an all-fiber Faraday mirror that rotates the polarization state of the reflected light by 88 +/- 4 degrees .

Effects of time on the magnetic properties of terbium-doped LaMnO3

International Nuclear Information System (INIS)

Liu Weibin; Zhang Yingtang; Guan Wen; Kinsman, William; Yuan Xinqiang; Chen Ziyu

2012-01-01

The magnetic properties of the perovskite form of LaMnO 3 have been shown strong interest in recent years due to its high potential for use in magnetic devices. In this paper, the magnetic properties of a 30% terbium-doped LaMnO 3 (LMTO) perovskite manganite synthesized by a conventional solid-state reaction were investigated. Data on these properties was recorded periodically via SQUID and VSM to reveal it to be best described magnetically as a spin glass system. Thus, the time effect must be taken into consideration in instantaneously determining this material’s spin glass state as well as the overall magnetic properties in the absence of a magnetic field. The results of this paper point to a more in-depth understanding of the change in magnetic properties associated with doped LaMnO 3 .

Flash combustion synthesis and characterisation of nanosized proton conducting Yttria-doped barium cerate

Energy Technology Data Exchange (ETDEWEB)

Jacquin, M.; Jing, Y.; Essoumhi, A.; Taillades, G.; Jones, D.J.; Roziere, J. [Montpellier Univ., Montpellier (France). Lab. des Agregats Moleculaires et Materiaux Inorganiques

2007-10-15

The high conversion efficiency of proton ceramic fuel cells renders them a promising technology for electric power conversion. They also function in an intermediate temperature range (400 to 600 degrees C) where the problem of thermal ageing can be avoided. This paper presented a newly developed flash combustion method for the preparation of proton conducting yttrium-doped barium cerate nanopowders. This quick, safe and low cost route takes advantage of the exothermic and self-sustaining redox reaction between high oxygen content metal salts and a suitable fuel that acts as a reducing agent. The parameters that influence the reaction product are the type of fuel, the fuel to oxidizer ratio, and the ignition temperature. Use of suitable fuel in combustion syntheses ensures stability of the chemical composition and high quality of products, and produces non-toxic gases. In this study, the flash combustion synthesis method was used to ignite the mixture at 600 degrees C. The resulting fine powder was characterized by transmission and scanning electron microscopy, and X-ray diffraction. The resulting nano-sized crystallites allow for the preparation of fully densified materials with densities up to 98 per cent. Water uptake was examined in compressed and sintered samples of BaCe{sub 0.9}Y{sub 0.1}O{sub 2.95} (BCY10). Bulk and total conductivities were determined with impedance spectroscopy in the range 300 to 600 degrees C. Densified yttria doped barium cerate materials show a bulk conductivity of 2.3 x 10{sup -2} S/cm and a total conductivity of 1.2 x 10{sup -2} S/cm at 500 degrees C. The temperature dependence was close to that of the bulk. It was concluded that flash combustion is an interesting alternative method for preparing proton conducting oxides for intermediate temperature fuel cells. 28 refs., 1 tab., 10 figs.

Niobium-doped strontium titanates as SOFC anodes

DEFF Research Database (Denmark)

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

2008-01-01

been synthesized with a recently developed modified glycine-nitrate process. The synthesized powders have been calcined and sintered in air or in 9% H(2) / N(2) between 800 - 1400 degrees C. After calcination the samples were single phase Nb-doped strontium titanate with grain sizes of less than 100 nm...... in diameter on average. The phase purity, defect structure, and microstructure of the materials have been analyzed with SEM, XRD, and TGA. The electrical conductivity of the Nb-doped titanate decreased with increasing temperature and showed a phonon scattering conduction mechanism with sigma > 120 S...... ability of the Nb-doped titanates to be used as a part of a SOFC anode. However, the catalytic activity of the materials was not sufficient and it needs to be improved if titanate based materials are to be realized as constituents in SOFC anodes....

Effects of time on the magnetic properties of terbium-doped LaMnO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Liu Weibin [Department of Physics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Zhang Yingtang, E-mail: zhangyingtang76@mail.xjtu.edu.cn [School of Material Science and Engineering, Institute of Functional Material, Shaanxi University of Technology, Hanzhong 723003 (China); State Key Laboratory of Electrical Insulation and Power Equipment and MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi' an Jiaotong University, Xi' an 710049 (China); Guan Wen [State Key Laboratory of Electrical Insulation and Power Equipment and MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi' an Jiaotong University, Xi' an 710049 (China); Kinsman, William [Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 (United States); Yuan Xinqiang [School of Material Science and Engineering, Institute of Functional Material, Shaanxi University of Technology, Hanzhong 723003 (China); Chen Ziyu [Department of Physics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China)

2012-09-01

The magnetic properties of the perovskite form of LaMnO{sub 3} have been shown strong interest in recent years due to its high potential for use in magnetic devices. In this paper, the magnetic properties of a 30% terbium-doped LaMnO{sub 3} (LMTO) perovskite manganite synthesized by a conventional solid-state reaction were investigated. Data on these properties was recorded periodically via SQUID and VSM to reveal it to be best described magnetically as a spin glass system. Thus, the time effect must be taken into consideration in instantaneously determining this material's spin glass state as well as the overall magnetic properties in the absence of a magnetic field. The results of this paper point to a more in-depth understanding of the change in magnetic properties associated with doped LaMnO{sub 3}.

Electrical behaviour of strontium-doped lanthanum manganite interfaces

DEFF Research Database (Denmark)

Koch, Søren; Hendriksen, P.V.; Jacobsen, Torben

2005-01-01

The contact resistance of strontium-doped lanthanum manganite (LSM) contact pairs is investigated by polarisation analysis at different temperatures and atmospheres. The ceramic contacts have a high contact resistance, and strongly nonlinear current–voltage behaviour is observed at low temperatur....... The nonlinear behaviour is ascribed to the presence of energy barriers at the contact interface. Generally, point contacts showed a more linear behaviour than plane contact interfaces....

Promoting the ambient-condition stability of Zr-doped barium cerate: Toward robust solid oxide fuel cells and hydrogen separation in syngas

Science.gov (United States)

Yang, Ying; Zeng, Yimin; Amirkhiz, Babak S.; Luo, Jing-Li; Yan, Ning

2018-02-01

Increasing the stability of perovskite proton conductor against atmospheric CO2 and moisture attack at ambient conditions might be equally important as that at the elevated service temperatures. It can ease the transportation and storage of materials, potentially reducing the maintenance cost of the integral devices. In this work, we initially examined the surface degradation behaviors of various Zr-doped barium cerates (BaCe0.7Zr0.1Y0.1Me0.1O3) using XRD, SEM, STEM and electron energy loss spectroscopy. Though that the typical lanthanide (Y, Yb and Gd) and In incorporated Zr-doped cerates well resisted CO2-induced carbonation in air at elevated temperatures, they were unfortunately vulnerable at ambient conditions, suffering slow decompositions at the surface. Conversely, Sn doped samples (BCZYSn) were robust at both conditions yet showed high protonic conductivity. Thanks to that, the anode supported solid oxide fuel cells equipped with BCZYSn electrolyte delivered a maximum power density of 387 mW cm-2 at 600 °C in simulated coal-derived syngas. In the hydrogen permeation test using BCZYSn based membrane, the H2 flux reached 0.11 mL cm-2 min-1 at 850 °C when syngas was the feedstock. Both devices demonstrated excellent stability in the presence of CO2 in the syngas.

Thermoelectric power and electrical conductivity of strontium-doped lanthanum manganite

DEFF Research Database (Denmark)

Ahlgren, E.O.; Poulsen, F.W.

1996-01-01

Thermoelectric power and electrical conductivity of pure and 5, 10 and 20% strontium-doped lanthanum manganite are determined as function of temperature in air and of P-O2 at 1000 degrees C. At high temperatures the thermoelectric power is negative. Both thermoelectric power and conductivity...

Doping site dependent thermoelectric properties of epitaxial strontium titanate thin films

KAUST Repository

Abutaha, Anas I.; Sarath Kumar, S. R.; Mehdizadeh Dehkordi, Arash; Tritt, Terry M.; Alshareef, Husam N.

2014-01-01

We demonstrate that the thermoelectric properties of epitaxial strontium titanate (STO) thin films can be improved by additional B-site doping of A-site doped ABO3 type perovskite STO. The additional B-site doping of A-site doped STO results in increased electrical conductivity, but at the expense of Seebeck coefficient. However, doping on both sites of the STO lattice significantly reduces the lattice thermal conductivity of STO by adding more densely and strategically distributed phononic scattering centers that attack wider phonon spectra. The additional B-site doping limits the trade-off relationship between the electrical conductivity and total thermal conductivity of A-site doped STO, leading to an improvement in the room-temperature thermoelectric figure of merit, ZT. The 5% Pr3+ and 20% Nb5+ double-doped STO film exhibits the best ZT of 0.016 at room temperature. This journal is

Preparation and luminescence properties of terbium-doped lanthanum oxide nanofibers by electrospinning

Energy Technology Data Exchange (ETDEWEB)

Song Lixin; Du Pingfan [Key Laboratory of Advanced Textile Materials and Manufacturing Technology (Zhejiang Sci-Tech University), Ministry of Education, Hangzhou 310018 (China); Xiong Jie, E-mail: jxiong@zstu.edu.cn [Key Laboratory of Advanced Textile Materials and Manufacturing Technology (Zhejiang Sci-Tech University), Ministry of Education, Hangzhou 310018 (China); Fan Xiaona; Jiao Yuxue [Key Laboratory of Advanced Textile Materials and Manufacturing Technology (Zhejiang Sci-Tech University), Ministry of Education, Hangzhou 310018 (China)

2012-01-15

Terbium-doped lanthanum oxide (La{sub 2}O{sub 3}:Tb{sup 3+}) nanofibers were prepared by electrospinning followed by calcination at high temperature. Thermogravimetric analyzer (TGA), field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and photoluminescence (PL) were used to characterize the obtained fibers. The results reveal that the nanofibers have an average diameter of ca. 95{+-}25 nm and are composed of pure La{sub 2}O{sub 3} phase. Under the excitation of 274 nm light, the La{sub 2}O{sub 3}:Tb{sup 3+} nanofibers exhibit the characteristic emission resulting from the {sup 5}D{sub 4}{yields}{sup 7}F{sub J} (J=3, 4, 5, 6) transitions of Tb{sup 3+} ions. And the PL emission intensity is stronger than that of their nanoparticle counterparts. - Highlights: > Tb{sup 3+}-doped La{sub 2}O{sub 3} (La{sub 2}O{sub 3}:Tb{sup 3+}) fluorescent nanofibers were prepared via a simple electrospinning technique. > Luminescent properties and other characteristics of the nanofibers were investigated in details. > Potential applications of La{sub 2}O{sub 3}:Tb{sup 3+} nanofibers and electrospinning technique described in this paper are suggested.

High-pressure liquid chromatography of trace elements: Determination of terbium in terbium doped gadolinium oxide sulphide phosphors

International Nuclear Information System (INIS)

Mazzucotelli, A.; Dadone, A.; Frache, R.; Baffi, F.; Genoa Univ.

1982-01-01

A detailed study of isocratic and gradient elution separations of lanthanides has been carried out. Analyses of industrially and scientifically interesting products such as luminescent phosphors have been carried out by gradient elution with DL-2-hydroxyisobutyric acid. The determination of small amounts of terbium in gadolinium oxide sulphide phosphors is described in which an HCl solution was eluted through a stainless steel column packed with microparticulate silica, with bonded cation-exchange groups. Complete separation of gadolinium and terbium is achieved. Detection is with a variable wavelength detector following post-column complex formation with 4-(2-pyridylazo)-resorcinol monosodium salt. Results obtained on test solutions show good reproducilbity and sensitivtiy and the method may be considered sufficiently reliable to be used in routine quality control procedures. (orig.)

Comparison study of biomimetic strontium-doped calcium phosphate coatings by electrochemical deposition and air plasma spray: morphology, composition and bioactive performance.

Science.gov (United States)

Li, Ling; Lu, Xia; Meng, Yizhi; Weyant, Christopher M

2012-10-01

In this study, strontium-doped calcium phosphate coatings were deposited by electrochemical deposition and plasma spray under different process parameters to achieve various coating morphologies. The coating composition was investigated by energy dispersive X-ray spectroscopy and X-ray diffraction. The surface morphologies of the coatings were studied through scanning electron microscopy while the cytocompatibility and bioactivity of the strontium-doped calcium phosphate coatings were evaluated using bone cell culture using MC3T3-E1 osteoblast-like cells. The addition of strontium leads to enhanced proliferation suggesting the possible benefits of strontium incorporation in calcium phosphate coatings. The morphology and composition of deposited coatings showed a strong influence on the growth of cells.

Strontium-doped organic-inorganic hybrids towards three-dimensional scaffolds for osteogenic cells

Energy Technology Data Exchange (ETDEWEB)

John, Łukasz, E-mail: lukasz.john@chem.uni.wroc.pl [Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław (Poland); Podgórska, Marta [Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław (Poland); Nedelec, Jean-Marie [Université Clermont Auvergne, SIGMA Clermont, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand (France); CNRS, UMR 6296, ICCF, F-63178 Aubiere (France); Cwynar-Zając, Łucja [Department of Histology and Embryology, Wrocław Medical University, 6a Chałubińskiego, 50-368 Wrocław (Poland); Dzięgiel, Piotr [Department of Histology and Embryology, Wrocław Medical University, 6a Chałubińskiego, 50-368 Wrocław (Poland); Department of Physiotherapy and Occupational Therapy in Conservative and Interventional Medicine, 35 Paderewskiego, 51-612 Wrocław (Poland)

2016-11-01

Biomimetic organic–inorganic hybrid bioscaffolds are developed to complement or replace damaged fragments in bone tissue surgery. The aim of this work was to develop a simple and fast method to prepare composite material for bone engineering, avoiding time consuming and complex methodologies. The resulting materials (also called in this work as hybrid composites or hybrid scaffolds) have a three-dimensional macroporous polymer-like network derived from triethoxyvinylsilane (TEVS) and 2-hydroxyethylmethacrylate (HEMA) monomers, with incorporated calcium, strontium, and phosphate ions. The materials were fully characterized using FT-IR, biomineralization studies, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy, scratch tests, Young's modulus and compressive strength tests, and gas physisorption. We report a comprehensive study on the in vitro effect of novel strontium doped materials on human bone cells. In vitro investigations were conducted using a normal human osteoblast cell line that mimics the cellular events of the in vivo intramembranous bone formation process. The materials do not have a negative impact on the survival of the normal human osteoblasts; moreover, materials doped with strontium show that not only are cells able to survive, but they also attach to and grow on a bioscaffolds surface. For this reason, they may be used in future in vivo experiments. - Highlights: • New hybrid scaffolds derived from TEVS and HEMA doped with Ca{sup 2+}, Sr{sup 2+}, and PO{sub 4}{sup 3-} ions have been developed. • A comprehensive characterization of the scaffolds for regenerative medicine was performed. • The incorporation of Sr{sup 2+} ions into the scaffolds was non-cytotoxic to the osteoblasts.

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.

Sensitivity improvement of Cerenkov luminescence endoscope with terbium doped Gd{sub 2}O{sub 2}S nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Cao, Xin; Chen, Xueli, E-mail: xlchen@xidian.edu.cn, E-mail: jimleung@mail.xidian.edu.cn; Cao, Xu; Zhan, Yonghua; Liang, Jimin, E-mail: xlchen@xidian.edu.cn, E-mail: jimleung@mail.xidian.edu.cn [Engineering Research Center of Molecular and Neuro Imaging of the Ministry of Education and School of Life Science and Technology, Xidian University, Xi' an, Shaanxi 710071 (China); Kang, Fei; Wang, Jing [Department of Nuclear Medicine, Xijing Hospital, Fourth Military Medical University, Xi' an, Shaanxi 710032 (China); Wu, Kaichun [Department of Digestive Diseases, Xijing Hospital, Fourth Military Medical University, Xi' an, Shaanxi 710032 (China)

2015-05-25

Our previous study showed a great attenuation for the Cerenkov luminescence endoscope (CLE), resulting in relatively low detection sensitivity of radiotracers. Here, a kind of radioluminescence nanoparticles (RLNPs), terbium doped Gd{sub 2}O{sub 2}S was mixed with the radionuclide {sup 68}Ga to enhance the intensity of emitted luminescence, which finally improved the detection sensitivity of the CLE by using the radioluminescence imaging technique. With the in vitro and in vivo pseudotumor experiments, we showed that the use of RLNPs mixed with the radionuclide {sup 68}Ga enabled superior sensitivity compared with the radionuclide {sup 68}Ga only, with 50-fold improvement on detection sensitivity, which guaranteed meeting the demands of the clinical diagnosis of gastrointestinal tract tumors.

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.

VUV and UV–vis optical study on KGd2F7 luminescent host doped with terbium and co-doped with europium

International Nuclear Information System (INIS)

Lisiecki, Radosław

2013-01-01

The KGd 2 F 7 :Tb and KGd 2 F 7 :Tb,Eu samples were obtained using a solid state reaction. Excitation spectra and emission spectra are reported and analyzed within the VUV–UV–vis spectral range. The intense green luminescence is observed in the KGd 2 F 7 :Tb while the combined emission of terbium and europium in the KGd 2 F 7 :Tb,Eu covers substantially the region of white light. The materials under study can be effectively excited making use of intense f–d transitions of Tb 3+ in the VUV–UV region. Experimental lifetimes of luminescent levels have been measured and discussed. It was found that the considerable energy transfer from Tb 3+ to Eu 3+ occurs. -- Highlights: • The prospective green and white emitting phosphors. • The effective VUV and UV–vis excitation process. • The considerable energy transfer among optically active ions. • The influence of (Tb, Eu) co-doping on relaxation dynamic of excited states

Risk of introducing exotic fruit flies, Ceratitis capitata, Ceratitis cosyra, and Ceratitis rosa (Diptera: Tephritidae), into southern China.

Science.gov (United States)

Li, Baini; Ma, Jun; Hu, Xuenan; Liu, Haijun; Wu, Jiajiao; Chen, Hongjun; Zhang, Runjie

2010-08-01

Exotic fruit flies (Ceratitis spp.) are often serious agricultural pests. Here, we used, pathway analysis and Monte Carlo simulations to assess the risk of introduction of Ceratitis capitata (Wiedemann), Ceratitis cosyra (Walker), and Ceratitis rosa Karsch, into southern China with fruit consignments and incoming travelers. Historical data, expert opinions, relevant literature, and archives were used to set appropriate parameters in the pathway analysis. Based on the ongoing quarantine/ inspection strategies of China, as well as the interception records, we estimated the annual number of each fruit fly species entering Guangdong province undetected with commercially imported fruit, and the associated risk. We also estimated the gross number of pests arriving at Guangdong ports with incoming travelers and the associated risk. Sensitivity analysis also was performed to test the impact of parameter changes and to assess how the risk could be reduced. Results showed that the risk of introduction of the three fruit fly species into southern China with fruit consignments, which are mostly transported by ship, exists but is relatively low. In contrast, the risk of introduction with incoming travelers is high and hence deserves intensive attention. Sensitivity analysis indicated that either ensuring all shipments meet current phytosanitary requirements or increasing the proportion of fruit imports sampled for inspection could substantially reduce the risk associated with commercial imports. Sensitivity analysis also provided justification for banning importation of fresh fruit by international travelers. Thus, inspection and quarantine in conjunction with intensive detection were important mitigation measures to reduce the risk of Ceratitis spp. introduced into China.

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.

Lattice dynamics of terbium

DEFF Research Database (Denmark)

Houmann, Jens Christian Gylden; Nicklow, R.M.

1969-01-01

Abstract only given substantially as follows. Neutron diffraction results are presented for the phonon dispersion relation of terbium......Abstract only given substantially as follows. Neutron diffraction results are presented for the phonon dispersion relation of terbium...

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...

Luminescent properties of terbium complex with phenylanthranilic acid

International Nuclear Information System (INIS)

Alakaeva, L.A.; Kalazhokova, I.A.; Naurzhanova, F.Kh.

1990-01-01

Existence of terbium luminescence reaction in complex with phenanthranilic acid (FAA) is ascertained. The optimal conditions of terbium complexing with FAA are found. The ratio of components in the complex is 1:1. The influence of foreign rare earth in terbium luminescence intensity in complex with FAA is studied

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.

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

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 distribution, relative abundance, and seasonal phenology of Ceratitis capitata, Ceratitis rosa, and Ceratitis cosyra (Diptera: Tephritidae) in South Africa.

Science.gov (United States)

De Villiers, Marelize; Manrakhan, Aruna; Addison, Pia; Hattingh, Vaughan

2013-10-01

Ceratitis capitata (Wiedemann), Ceratitis rosa Karsch, and Ceratitis cosyra (Walker) are fruit fly species (Diptera: Tephritidae) of economic importance in South Africa. These pests cause direct damage to a number of commercially produced fruit and are of phytosanitary concern. A study was conducted to determine the distribution, relative abundance, and seasonal occurrence of the three species in different climatic regions of South Africa. The relative abundance and seasonal phenology of C. capitata and C. rosa were also compared between production areas and home gardens in Stellenbosch, Western Cape. Yellow bucket traps baited with Biolure were used to trap the flies over a 2-yr period in the different sampling areas. Different fruit types were sampled in Stellenbosch to determine fruit fly infestation. C. capitata was found to have a widespread distribution in South Africa, whereas C. rosa were absent from or only present in low numbers in the drier regions. C. cosyra was restricted to the North East and East coast, following a similar pattern to the distribution of marula, Sclerocarrya birrea, an important wild host. Fruit in home gardens provided a breeding ground for C. capitata and C. rosa and a source for infestation of orchards when fruit started to mature, highlighting the need for an area-wide strategy for the control of fruit flies.

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

Fabricating Bis(phthalocyaninato) Terbium SIM into Tetrakis(phthalocyaninato) Terbium SMM with Enhanced Performance through Sodium Coordination.

Science.gov (United States)

Chen, Yuxiang; Liu, Chao; Ma, Fang; Qi, Dongdong; Liu, Qingyun; Sun, Hao-Ling; Jiang, Jianzhuang

2018-04-23

The non-peripherally substituted 1,4,8,11,15,18,22,25-octa(butoxy)-phthalocyanine-involved unsymmetrical heteroleptic bis(phthalocyaninato) terbium double-decker, Tb(Pc){H[Pc(α-OC 4 H 9 ) 8 ]} (Pc=unsubstituted phthalocyanine) (1), was revealed to exhibit typical single ion magnet (SIM) behavior with effective energy barrier, 180 K (125 cm -1 ), and blocking temperature, 2 K, due to the severe deviation of the terbium coordination polyhedron from square-antiprismatic geometry. Fabrication of this double-decker compound into the novel tetrakis(phthalocyaninato) terbium pseudo-quadruple-decker Na 2 {Tb(Pc)[Pc(α-OC 4 H 9 ) 8 ]} 2 (2) single molecule magnet (SMM) not only optimizes the coordination polyhedron of terbium ion towards the square-antiprismatic geometry and intensifies the coordination field strength, but more importantly significantly enhances the molecular magnetic anisotropy in the unsymmetrical bis(phthalocyaninato) double-decker unit, along with the change of the counter cation from H + of 1 to Na + of 2, leading to an significantly enhanced magnetic behavior with spin-reversal energy barrier, 528 K (367 cm -1 ), and blocking temperature, 25 K. The present result is surely helpful towards developing novel tetrapyrrole lanthanide SMMs through rational design and self-assembly from bis(tetrapyrrole) lanthanide single ion magnet (SIM) building block. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

Electroanalytical performance of a terbium(III)-selective sensor based on a neutral ionophore in environmental and medicinal samples

Energy Technology Data Exchange (ETDEWEB)

Gupta, V.K.; Singh, A.K.; Gupta, Barkha [Indian Institute of Technology-Roorkee, Department of Chemistry, Roorkee (India)

2008-04-15

A new highly selective terbium(III) electrode was prepared with a polymeric film doped using S-2-benzothiazolyl-2-amino-{alpha}-(methoxyimino)-4-thiazolethiol acetate as an electroactive material, benzyl acetate (BA) as a plasticizer, and potassium tetrakis(4-chlorophenyl) borate (KTpClPB) as an anionic site in the percentage ratio 3.17:1.58:63.4:31.7 (ionophore-KTpClPB-BA-PVC, w/w). The electrode exhibited a linear response with a near Nernstian slope of 19.5 mV/decade within the concentration range 1.5 x 10{sup -7}-1.0 x 10{sup -2} M terbium ions, with a working pH range from 2.0 to 8.0, and a fast response time of 10 s and presented satisfactory reproducibility. The limit of detection was 9.3 x 10{sup -8} M. The results show that this electrode can be used in ethanol media up to 30% (v/v) concentration without interference. It can be used for 3 months without any considerable divergence in the potentials. Selectivity coefficients for terbium(III) with respect to many cations were investigated. The electrode is highly selective for terbium(III) ions over a large number of monovalent, bivalent, and trivalent cations. This shows the valuable property of the proposed electrode. The stability constant of the ionophore towards Tb{sup 3+} ions was determined with the sandwich membrane method. It was successfully used as an indicator electrode in potentiometric determination of terbium(III) ions with EDTA and in direct determination in tap water and binary mixtures with quantitative results. The utility of the proposed electrode was also determined in the presence of ionic and nonionic surfactants and in the presence of fluoride ions in four pharmaceutical (mouthwash) preparations. (orig.)

Electroanalytical performance of a terbium(III)-selective sensor based on a neutral ionophore in environmental and medicinal samples

International Nuclear Information System (INIS)

Gupta, V.K.; Singh, A.K.; Gupta, Barkha

2008-01-01

A new highly selective terbium(III) electrode was prepared with a polymeric film doped using S-2-benzothiazolyl-2-amino-α-(methoxyimino)-4-thiazolethiol acetate as an electroactive material, benzyl acetate (BA) as a plasticizer, and potassium tetrakis(4-chlorophenyl) borate (KTpClPB) as an anionic site in the percentage ratio 3.17:1.58:63.4:31.7 (ionophore-KTpClPB-BA-PVC, w/w). The electrode exhibited a linear response with a near Nernstian slope of 19.5 mV/decade within the concentration range 1.5 x 10 -7 -1.0 x 10 -2 M terbium ions, with a working pH range from 2.0 to 8.0, and a fast response time of 10 s and presented satisfactory reproducibility. The limit of detection was 9.3 x 10 -8 M. The results show that this electrode can be used in ethanol media up to 30% (v/v) concentration without interference. It can be used for 3 months without any considerable divergence in the potentials. Selectivity coefficients for terbium(III) with respect to many cations were investigated. The electrode is highly selective for terbium(III) ions over a large number of monovalent, bivalent, and trivalent cations. This shows the valuable property of the proposed electrode. The stability constant of the ionophore towards Tb 3+ ions was determined with the sandwich membrane method. It was successfully used as an indicator electrode in potentiometric determination of terbium(III) ions with EDTA and in direct determination in tap water and binary mixtures with quantitative results. The utility of the proposed electrode was also determined in the presence of ionic and nonionic surfactants and in the presence of fluoride ions in four pharmaceutical (mouthwash) preparations. (orig.)

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)

Production and separation of terbium-149 and terbium-152 for targeted cancer therapy

International Nuclear Information System (INIS)

Sarkar, S.; Leigh, J.

1997-01-01

This work reports the production and separation of useful quantities of 149 , 152 Tb from natural neodymium ( nat Nd) and 141 Pr for in vitro studies by bombarding the targets with 12 C projectiles. The physical, chemical and nuclear properties of radionuclides determine their efficacy in therapy and diagnosis. Tb-149 is an alpha-emitter with a half-life of 4.1h and 152 Tb is a positron emitter with a half-life of 17.5 h. Both of the isotopes have suitable gamma emission with good branching ratio suggesting their application to diagnosis apart from therapy. Alpha-emitters are effective in controlling cancer because of their short range and high Relative Biological Effectiveness. Long-lived positron emitters are effective in studying physiological function in positron emission tomography other than therapy. The aim of this work is to optimise the production and carrier free separation of terbium. Because of the presence of other stable isotopes in nat Nd, a number of other lanthanides are produced by secondary reactions during the production of terbium. In order to remove the secondary products, α-hydroxyisobutyric acid of pH 5 was used as eluent. satisfactory separation of terbium was achieved and demonstrate that useful quantities of 144,152 Tb can be produced by Tandem accelerator from 141 Pr and nat Nd targets

Population genetics of the potentially invasive African fruit fly species, Ceratitis rosa and Ceratitis fasciventris (Diptera: Tephritidae).

Science.gov (United States)

Baliraine, F N; Bonizzoni, M; Guglielmino, C R; Osir, E O; Lux, S A; Mulaa, F J; Gomulski, L M; Zheng, L; Quilici, S; Gasperi, G; Malacrida, A R

2004-03-01

A set of 10 microsatellite markers was used to survey the levels of genetic variability and to analyse the genetic aspects of the population dynamics of two potentially invasive pest fruit fly species, Ceratitis rosa and C. fasciventris, in Africa. The loci were derived from the closely related species, C. capitata. The degree of microsatellite polymorphism in C. rosa and C. fasciventris was extensive and comparable to that of C. capitata. In C. rosa, the evolution of microsatellite polymorphism in its distribution area reflects the colonization history of this species. The mainland populations are more polymorphic than the island populations. Low levels of differentiation were found within the Africa mainland area, while greater levels of differentiation affect the islands. Ceratitis fasciventris is a central-east African species. The microsatellite data over the Uganda/Kenya spatial scale suggest a recent expansion and possibly continuing gene flow within this area. The microsatellite variability data from C. rosa and C. fasciventris, together with those of C. capitata, support the hypothesis of an east African origin of the Ceratitis spp.

Luminescent determination of trace amounts of terbium using diantipyrylmethane and salicylic acid

Energy Technology Data Exchange (ETDEWEB)

Tishchenko, M A; Gerasimenko, G I; Poluehktov, N S [AN Ukrainskoj SSR, Odessa. Inst. Obshchej i Neorganicheskoj Khimii

1978-01-01

To elucidate the possibility of using pyrazolone-5-diantipyril-methane (DAM) derivative for determination of terbium microimpurities, the conditions have been studied of luminescent determination of terbium in complex compounds containing an ion of rare-earth element, diantipyrilmethane, and salicylic acid (Sal.). The ratio between the components in the complex REE-DAM-Sal is 1:1:3. La, Y, Gd do not affect the luminescence intensity of terbium complex. A luminescent method of determining terbium traces in highly pure oxides of lanthanum, gadolinium, lutetium, and yttrium has been developed in which suspensions of complex precipitation are used. The amount of terbium determined in oxide of lanthanum, gadolinium, and lutetium is (1-5)x10/sup -6/% and (2-3)x10/sup -5/% in yttrium oxide.

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.

Fine structure studies of terbium atoms

International Nuclear Information System (INIS)

Abhay Kumar; Bandyopadhyay, Krishnanath; Niraj Kumar

2012-01-01

Terbium (Z = 65) is a typical rare-earth element. Fine structure of spectural lines of terbium (Tb) are presented using the laser optogalvanic spectroscopic technique. Altogether eighty transitions in the 5686-6367 A range have been observed in the fine structure spectrum of 159 Tb. Wavelengths of all the observed transitions have been determined. Out of 80 transitions of Tb, a total of 59 transitions are being reported for the first time. Classifications of 39 new transitions have been provided using the known energy levels, Doppler-limited optogalvanic spectroscopic technique is employed to study the fine structure (fs) 159 Tb. (author)

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)

An integrative approach to unravel the Ceratitis FAR (Diptera, Tephritidae) cryptic species complex: a review

Czech Academy of Sciences Publication Activity Database

De Meyer, M.; Delatte, H.; Ekesi, S.; Jordaens, K.; Kalinová, Blanka; Manrakhan, A.; Mwatawala, M.; Steck, G.; Van Cann, J.; Vaníčková, Lucie; Břízová, R.; Virgilio, M.

-, č. 540 (2015), s. 405-427 ISSN 1313-2989 Institutional support: RVO:61388963 Keywords : taxonomy * Ceratitis rosa * Ceratitis fasciventris * Ceratitis anonae * Africa * fruit fly Subject RIV: EG - Zoology Impact factor: 0.938, year: 2015 http://zookeys.pensoft.net/articles.php?id=6059

Lattice dynamics of terbium

DEFF Research Database (Denmark)

Houmann, Jens Christian Gylden; Nicklow, R.M.

1970-01-01

The frequency-wave-vector dispersion relation for the normal modes of vibration of terbium at room temperature has been measured by means of slow-neutron inelastic scattering techniques. The triple-axis spectrometer at the Oak Ridge high flux isotope reactor was used, mostly in the constant-Q mode...

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.

Direct determination of graphene quantum dots based on terbium-sensitized luminescence

Science.gov (United States)

Llorent-Martínez, Eulogio J.; Molina-García, Lucía; Durán, Gema M.; Ruiz-Medina, Antonio; Ríos, Ángel

2018-06-01

Graphene quantum dots (GQD) were determined in water samples using terbium-sensitized luminescence (TSL). Terbium ions complex with GQD due to the carboxylic groups that are usually present in these nanomaterials, increasing the luminescence signal of terbium. In Tb(III)-GQD complexes, GQD absorb energy at their characteristic excitation wavelength and transfer it to terbium ion, which emits at its particular emission wavelength. The analytical signal, measured at λexc = 257 nm and λem = 545 nm, increases proportionally to GQD concentration between 50 and 500 μg L-1. Under optimum conditions, the proposed method presents a detection limit of 15 μg L-1 and is selective to GQD in the presence of other nanomaterials of similar size. As GQD are highly water-soluble, they are potential contaminants in environmental or drinking waters water samples, and hence the method was applied to the analysis of different drinking waters which were the target samples for the application of the developed method.

Study of quantum dot based on tin/yttrium mixed oxide doped with terbium to be used as biomarker

International Nuclear Information System (INIS)

Paganini, Paula P.; Felinto, Maria Claudia F.C.; Kodaira, Claudia A.; Brito, Hermi F.; Nunes, Luiz Antonio O.

2009-01-01

Quantum dots (semiconductors nanocrystals) have brought a promising field to develop a new generation of luminescent biomarkers. The use of lanthanides ions as luminescent markers has many advantages, for example a security method, low cost, high specificity and also the luminescence can be promptly measured with high sensibility and accuracy. These luminescent dots are functionalized with biomolecules. For the luminophore particle to be connect with biologicals molecules (for example covalent antibody) is necessary a previous chemical treatment to modify luminophore particle surface and this process is called functionalization. A prior chemical treatment with changes on the surface luminophore particle is necessary to couple the luminophore to biological molecules. This process can be used as coating which can protect these particles from being dissolved by acid as well as provide functional groups for biological conjugation. This work presents a photoluminescence study of nanoparticles based on tin/yttrium mixed oxides doped with terbium (SnO 2 /Y 2 O 3 :Tb 3+ ), synthesized by coprecipitation method. The nanoparticles were submitted to thermal treatment and characterized by X-Ray Powder Diffraction (XRD) that showed cassiterite phase formation and the influence of thermal treatment on nanoparticles structures. These nanoparticles going to be functionalized with a natural polysaccharide (chitosan) in order to form microspheres. These microspheres going to be irradiated with gamma radiation to sterilization and it can be evaluated if the nanoparticles are resistant to irradiation and they do not lose functionality with this process. (author)

Magneto-elastic interactions in terbium

DEFF Research Database (Denmark)

Jensen, J.

1971-01-01

. These calculations agree semi-quantitatively with the results of experimental measurements. The author has examined the extent to which this simple picture is applicable to explain the magnon-phonon interactions in terbium, which have been observed at finite wave vectors by inelastic neutron scattering...

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

Directory of Open Access Journals (Sweden)

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

Directory of Open Access Journals (Sweden)

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.

First Occurrence of Ceratitis capitata (Wied. in the State of Roraima, Brazil = Primeira ocorrência de Ceratitis capitata (Wied. no Estado de Roraima, Brasil

Directory of Open Access Journals (Sweden)

Luciana Baú Trassato

2017-03-01

Full Text Available Due to its cosmopolitan and invasive characteristics, the Mediterranean fruit fly, Ceratitis capitata (Wied., is considered to be the most harmful tephritide to global fruit farming, causing greater losses in production than any other species of the same family. In Brazil, it was first detected in 1901 in the state of São Paulo, and was present in 22 of the 27 federated states by 2014. Because of its economic importance and the continual entry of hosts into the state, the hypothesis of this work was that the Mediterranean fruit fly [Ceratitis capitata (Wied.] is already present in the State of Roraima. Weekly collections of potential host fruits were carried out in October 2014 in urban areas of the city of Boa Vista, Roraima. The collected fruit was taken to the Entomology Laboratory of the Federal University of Roraima, where they were weighed, counted and packed under controlled conditions of temperature and humidity in order to obtain pupae. After emergence, the flies were fed on water with 25% honey for two days, fixed in 70% alcohol and sent for identification to the Department of Entomology Research of the Amazon National Research Institute (INPA in Manaus. In this way, Specimens of Ceratitis capitata (Wied. (Diptera: Thephritidae were detected in fruit of the guava (Psidium guajava L., validating the hypothesis that the pest is already present in Roraima. The first record of the occurrence of Ceratitis capitata (Wied. in the state of Roraima is therefore reported here. = A mosca-do-mediterrâneo, Ceratitis capitata (Wied., por apresentar características cosmopolita e invasora, é considerada o tefritideo mais nocivo à fruticultura mundial, causando perdas produtivas superiores a qualquer outra espécie da sua família. No Brasil, foi primeiramente detectada em 1901 no estado de São Paulo, e estava presente em 22 das 27 unidades federativas até o ano de 2014. Em razão da sua importância econômica e da constante entrada de

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

Directory of Open Access Journals (Sweden)

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.

Physico- chemical study of Ceratitis capitata rearing diet

International Nuclear Information System (INIS)

El Sghiri, Mohamed Ali; Maddouri Fakri

2005-01-01

The inhibition of the microbial growth in the rearing diet of ceratitis capitata made it possible to increase the productivity in pupae. The follow-up of the microbial load and the physicochemical parameters of the diets used with varous microbial inhibitors (potassium sorbate in combination with sodium benzoate with varous amounts, on the one hand, and of another share, nipagine in combination with sodium benzoate also with varous amounts) during a rearing of ceratitis capitata on the laboratory scale made it possible to select the diet D as being the most favorable diet. Indeed, a stability of the physico chemical parameters as well as a weak evolution of the microbial load are noted in this diet. (author). 16 refs

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.

Structural and morphological analysis of barium cerate electrolyte for SOFC application

Directory of Open Access Journals (Sweden)

Senthil Kumar A.

2017-02-01

Full Text Available Gadolinium doped barium cerate (BCG electrolytes Ce0.8Gd0.2O1.9 + xBaO (x = 0.1 and 0.4 were prepared by wet chemical method for the use in solid oxide fuel cells operating at intermediate temperatures (600 °C to 800 °C. The as-prepared powder sample was calcined at 900 °C. The calcination temperature was identified using differential scanning calorimetry (DSC analysis. The orthorhombic perovskite phase formation was confirmed by XRD analysis. From TEM results, the particle size was found to be about 32 nm which is in a good agreement with XRD results. BCG nanoparticles were formed at lower sintering temperature due to using microwave furnace. By reducing the sintering temperature of solid electrolyte through microwave technique, the percentage of barium loss was successfully reduced and the prepared electrolyte can be a good choice for solid oxide fuel cells operating at intermediate temperatures.

Synthesis and characterization of Tin / Titanium mixed oxide nanoparticles doped with lanthanide for biomarking

International Nuclear Information System (INIS)

Paganini, Paula Pinheiro

2012-01-01

This work presents the synthesis, characterization and photo luminescent study of tin and titanium mixed oxide nanoparticles doped with europium, terbium and neodymium to be used with luminescent markers on biological systems. The syntheses were done by co-precipitation, protein sol-gel and Pechini methods and the nanoparticles were characterized by infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, X-ray diffraction and X-ray absorption spectroscopy. The photo luminescent properties studies were conducted for luminophores doped with europium, terbium and neodymium synthesized by coprecipitation method. For luminophore doped with europium it was possible to calculate the intensity parameters and quantum yield and it showed satisfactory results. In the case of biological system marking it was necessary the functionalization of these particles to allow them to bind to the biological part to be studied. So the nanoparticles were functionalized by microwave and Stöber methods and characterized by infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction obtaining qualitative response of functionalization efficacy. The ninhydrin spectroscopic method was used for quantification of luminophores functionalization. The photo luminescent studies of functionalized particles demonstrate the potential applying of these luminophores as luminescent markers. (author)

Terbium and dysprosium complexes luminescence at low temperatures

Energy Technology Data Exchange (ETDEWEB)

Meshkova, S B; Kravchenko, T B; Kononenko, L.I.; Poluehktov, N S [AN Ukrainskoj SSR, Odessa. Fiziko-Khimicheskij Inst.

1979-01-01

The variation is studied of the luminescence intensity of terbium and dysprosium complexes used in the analysis as solutions are cooled down to the liquid nitrogen temperature. Three groups of methods have been studied: observation of fluorescence of aqueous solutions, precipitate and extract suspensions in organic solvents. The brightest luminescence and greatest increase in luminescence intensity are observed at freezing of complex solvents with 1,2-dioxybenzene-3,5-disulfonic acid (DBSA) and iminodiacetic acid (IDA) and DBSA+EDTA, as well as in the case of benzene extracting of complexes with phenanthroline and salicylic acid. Otherwise the intensity increases 2-14-fold and for the complex of terbium with acetoacetic ester 36-fold.

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.

Picomolar traces of americium(III) introduce drastic changes in the structural chemistry of terbium(III). A break in the ''gadolinium break''

Energy Technology Data Exchange (ETDEWEB)

Welch, Jan M. [TU Wien, Atominstitut, Vienna (Austria); Mueller, Danny; Knoll, Christian; Wilkovitsch, Martin; Weinberger, Peter [TU Wien, Institute of Applied Synthetic Chemistry, Vienna (Austria); Giester, Gerald [University of Vienna, Institute of Mineralogy and Crystallography, Vienna (Austria); Ofner, Johannes; Lendl, Bernhard [TU Wien, Institute of Chemical Technologies and Analytics, Vienna (Austria); Steinhauser, Georg [Leibniz Universitaet Hannover, Institute of Radioecology and Radiation Protection (Germany)

2017-10-16

The crystallization of terbium 5,5{sup '}-azobis[1H-tetrazol-1-ide] (ZT) in the presence of trace amounts (ca. 50 Bq, ca. 1.6 pmol) of americium results in 1) the accumulation of the americium tracer in the crystalline solid and 2) a material that adopts a different crystal structure to that formed in the absence of americium. Americium-doped [Tb(Am)(H{sub 2}O){sub 7}ZT]{sub 2} ZT.10 H{sub 2}O is isostructural to light lanthanide (Ce-Gd) 5,5{sup '}-azobis[1H-tetrazol-1-ide] compounds, rather than to the heavy lanthanide (Tb-Lu) 5,5{sup '}-azobis[1H-tetrazol-1-ide] (e.g., [Tb(H{sub 2}O){sub 8}]{sub 2}ZT{sub 3}.6 H{sub 2}O) derivatives. Traces of Am seem to force the Tb compound into a structure normally preferred by the lighter lanthanides, despite a 10{sup 8}-fold Tb excess. The americium-doped material was studied by single-crystal X-ray diffraction, vibrational spectroscopy, radiochemical neutron activation analysis, and scanning electron microscopy. In addition, the inclusion properties of terbium 5,5{sup '}-azobis[1H-tetrazol-1-ide] towards americium were quantified, and a model for the crystallization process is proposed. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

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)

Critical scattering of neutrons from terbium

DEFF Research Database (Denmark)

Als-Nielsen, Jens Aage; Dietrich, O.W.; Marshall, W.

1968-01-01

The inelasticity of the critical scattering of neutrons in terbium has been measured above the Neél temperature at the (0, 0, 2−Q) satellite position. The results show that dynamic slowing down of the fluctuations does occur in a second‐order phase transition in agreement with the general theory...

Elastic properties of terbium

DEFF Research Database (Denmark)

Spichkin, Y.I.; Bohr, Jakob; Tishin, A.M.

1996-01-01

The temperature dependence of the Young modulus along the crystallographic axes b and c (E(b) and E(c)), and the internal friction of a terbium single crystal have been measured. At 4.2 K, E(b) and E(c) are equal to 38 and 84.5 GPa, respectively. The lattice part of the Young modulus and the Debye...... temperature has been calculated. The origin of the Young modulus anomalies arising at the transition to the magnetically ordered state is discussed....

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.

Systems of pyridine, piperidine, piperazine, morpholine hydrochlorides-terbium (dysprosium) chloride-water

International Nuclear Information System (INIS)

Gajfutdinova, R.K.; Sharafutdinova, A.A.; Murinov, Yu.I.

1988-01-01

The isothermal cross section method at 25 and 50 deg C is applied to study pyridine hydrochloride-terbium chloride-water (1) piperidine hydrochloride-dysprosium chloride-water (2), piperazine dihydrochloride-dysprosium chloride-water (3) and morpholine hydrochloride-terbium chloride (4) systems. Solubility isotherma prove the formation of incongruently soluble compound of the TbCl 3 x6C 5 H 5 NxHCl composition systems (1). The individuality of the new solid phase is proved by the chemical and DTA methods. Systems (2-4) are of a simple eutonic type

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

Investigation of terbium scandate as an alternative gate dielectric in fully depleted transistors

OpenAIRE

Roeckerath, M.; Lopes, J. M. J.; Durgun Özben, E.; Urban, C.; Schubert, J.; Mantl, S.; Jia, Y.; Schlom, D.G.

2010-01-01

Terbium scandate thin films were deposited by e-gun evaporation on (100) silicon substrates. Rutherford backscattering spectrometry and x-ray diffraction studies revealed homogeneous chemical compositions of the films. A dielectric constant of 26 and CV-curves with small hystereses were measured as well as low leakage current densities of < 1 nA/cm(2). Fully depleted n-type field-effect transistors on thin silicon-on-insulator substrates with terbium scandate gate dielectrics were fabricated ...

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.

Infrared X-ray and thermal analysis of terbium soaps

International Nuclear Information System (INIS)

Mehrotra, K.N.; Sharma, N.

1996-01-01

Terbium sops (laureate, myristate and palmitate) were synthesized by direct metathesis of corresponding potassium soap with an aqueous solution of terbium nitrate. The physico-chemical characteristics of soaps in solid state were investigated by IR spectra, X-ray diffraction patterns and TGA measurements. The IR results revealed that the fatty acids exist in dimeric state through hydrogen bonding while the soaps possess partial ionic character. The X-ray analysis showed that the soaps have double layer structure with molecular axes slightly inclined to the basal plane. The thermal analysis suggested that the decomposition of soaps occur in two steps. The energy of activation, order of reaction and various kinetic parameters (i.e. frequency factor, entropy of activation and free energy) for the thermal decomposition of soaps were evaluated. (author). 26 refs, 4 figs, 4 tabs

Synthesis and novel fluorescence phenomenon of terbium(III) complex with N, N',N' -tris (2-benzimidazolmethyl) amine

International Nuclear Information System (INIS)

Yang, Tianlin; Gao, Min; Yang, Jinhui; Qin, Wenwu

2010-01-01

A benzimidazole ligand with a tripodal structure, N, N', N' -tris (2-benzimidazolmethyl) amine, and its terbium (III) complex has been synthesized. The complex has been characterized by element analysis, IR spectra, mass spectra, thermal analysis and molar conductivity. The terbium ion is found to coordinate with the nitrogen atoms (= N-) of imidazole ring and the bridgehead nitrogen atom. The fluorescence properties of the complex in aqueous solutions have been studied. Under excitation of UV light, the complex exhibits characteristic fluorescence of terbium ion. The luminescence of terbium complex in aqueous solutions is strongly enhanced by H + concentration. This phenomenon makes the new complex favorable for use in fluorescence switches and sensors. The mechanism of the fluorescence enhancement by protonation of the nitrogen atoms (-NH-) of imidazole ring is due to the suppressed photoinduced electron transfer fluorescence quenching on addition of acid. (author)

Nuclear magnetic resonance in ferromagnetic terbium metal

International Nuclear Information System (INIS)

Cha, C.L.T.

1974-01-01

The magnetic properties of terbium were studied by the method of zero field nuclear magnetic resonance at 1.5 to 4 and 85 to 160 0 K. Two unconventional experimental techniques have been employed: the swept frequency and the swept temperature technique. Near 4 0 K, triplet resonance line structures were found and interpreted in terms of the magnetic domain and wall structures of ferromagnetic terbium. In the higher temperature range, temperature dependence of the resonance frequency and the quadrupole splitting were measured. The former provides a measurement of the temperature dependence of the magnetization M, and it agrees with bulk M measurements as well as the latest spin wave theory of M(T) (Brooks 1968). The latter agrees well with a calculation using a very general single ion density matrix for collective excitations (Callen and Shtrikman 1965). In addition, the small temperature-independent contribution to the electric field gradient at the nucleus due to the lattice and conduction electrons was untangled from the P(T) data. Also an anomalous and unexplained relaxation phenomenon was also observed

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.

The condition for electroplex emission from an europium complex doped poly( N-vinylcarbazole)

Science.gov (United States)

Zhang, T.; Xu, Z.; Qian, L.; Tao, D. L.; Teng, F.; Gao, X.; Xu, X. R.

2005-10-01

Spectral characteristics of photoluminescence (PL) and electroluminescence (EL) of poly( N-vinylcarbazole) (PVK) matrices doped with a novel europium complex Eu(aspirin) 3phen were investigated. A red-shift and broadening were observed in the EL spectra but not in the PL ones. However, neither red-shift nor broadening were observed in the EL spectra of PVK doped with a similar complex with the same ligand, terbium complex (Tb(aspirin) 3phen). This result suggests the formation of electroplexes in blend systems, which is likely due to inefficient energy transfer from host molecules to dopant molecules.

New genetic tools for improving SIT in Ceratitis capitata: embryonic lethality and sperm marking

International Nuclear Information System (INIS)

Schetelig, Marc F.; Wimmer, Ernst A.; Scolari, Francesca; Gasperi, Giuliano; Handler, Ernst A.

2006-01-01

Environment friendly sterile insect technique (SIT) is being applied effectively as a component of area-wide integrated pest management (AW-IPM) for Ceratitis capitata since 1970s. Nevertheless improved biological strategies are needed to increase the efficacy of AW-IPM. Transgenic approaches should increase and widen the applicability of such programmes to different pest species. In this respect two major strategies are followed: First an approach to cause sterility was designed without interfering with spermatogenesis to maintain males and their sperm as competitive as possible. We followed a strategy, which is based on the expression of a lethal factor under the control of a promoter that is active at early blastoderm stages. The system employs the ectopic expression of a hyperactive pro apoptotic gene that causes embryo-specific lethality when driven by the tetracycline-controlled trans activator tTA under the regulation of a cellularization gene enhancer/promoter. The system has been tested successfully in Drosophila melanogaster (Horn and Wimmer 2003). We tried the direct transfer of the Drosophila system to Ceratitis capitata by injecting the respective constructs that carry Drosophila-derived promoters. Unfortunately, the cellularization specific promoters from Drosophila seem not functional in Ceratitis. Therefore, the corresponding enhancers/promoters from Ceratitis were isolated and subsequently the tTA was brought independently under the control of each enhancer/promoter region. These constructs were injected in Ceratitis for further evaluation. Second, we have engineered a medfly strain carrying a sperm marking system. This strain carries two fluorescent markers. One (turboGFP) marker is under the control of the spermatogenesis specific b2-tubulin promoter from Ceratitis and is therefore sperm specifically expressed. The second (DsRed) is under the control of the poly ubiquitin promoter of Drosophila. Released males from this strain could be

New genetic tools for improving SIT in Ceratitis capitata: embryonic lethality and sperm marking

Energy Technology Data Exchange (ETDEWEB)

Schetelig, Marc F; Wimmer, Ernst A [Georg-August-University, Gottingen (Germany). Johann-Friedrich Blumenbach Institute of Zoology and Anthropology. Gottingen Center for Molecular Biosciences; Scolari, Francesca; Gasperi, Giuliano [Universita di Pavia (Italy). Dipt. di Biologia Animale; Handler, Ernst A [U.S. Department of Agriculture (USDA/ARS), Gainesville, FL (United States). Agricultural Research Service. Center for Medical, Agricultural and Veterinary Entomology

2006-07-01

Environment friendly sterile insect technique (SIT) is being applied effectively as a component of area-wide integrated pest management (AW-IPM) for Ceratitis capitata since 1970s. Nevertheless improved biological strategies are needed to increase the efficacy of AW-IPM. Transgenic approaches should increase and widen the applicability of such programmes to different pest species. In this respect two major strategies are followed: First an approach to cause sterility was designed without interfering with spermatogenesis to maintain males and their sperm as competitive as possible. We followed a strategy, which is based on the expression of a lethal factor under the control of a promoter that is active at early blastoderm stages. The system employs the ectopic expression of a hyperactive pro apoptotic gene that causes embryo-specific lethality when driven by the tetracycline-controlled trans activator tTA under the regulation of a cellularization gene enhancer/promoter. The system has been tested successfully in Drosophila melanogaster (Horn and Wimmer 2003). We tried the direct transfer of the Drosophila system to Ceratitis capitata by injecting the respective constructs that carry Drosophila-derived promoters. Unfortunately, the cellularization specific promoters from Drosophila seem not functional in Ceratitis. Therefore, the corresponding enhancers/promoters from Ceratitis were isolated and subsequently the tTA was brought independently under the control of each enhancer/promoter region. These constructs were injected in Ceratitis for further evaluation. Second, we have engineered a medfly strain carrying a sperm marking system. This strain carries two fluorescent markers. One (turboGFP) marker is under the control of the spermatogenesis specific b2-tubulin promoter from Ceratitis and is therefore sperm specifically expressed. The second (DsRed) is under the control of the poly ubiquitin promoter of Drosophila. Released males from this strain could be

Terbium nitrate luminescence quenching by eosin in he presence of lithium perchlorate in sulfolane solutions

International Nuclear Information System (INIS)

Ostakhov, S.S.; Kolosnitsyn, V.S.; Krasnogorskaya, N.N.; Kazakov, V.P.

2000-01-01

Quenching of terbium nitrate luminescence by anionic dye, eosin, in the presence of lithium perchlorate in sulfolane solutions was studied. Temperature dependence of terbium nitrate luminescence in sulfolane solutions in the presence of perchlorate anions were considered. The values of energy required for water molecular substitution in Tb 3+ ion coordination sphere for solvent molecule in electrolyte solution were ascertained [ru

Radioluminescence of rare-earth doped aluminum oxide

Energy Technology Data Exchange (ETDEWEB)

Santiago, M.; Molina, P. [Universidad Nacional del Centro de la Provincia de Buenos Aires, Instituto de Fisica Arroyo Seco, Pinto 399, 7000 Tandil (Argentina); Barros, V. S.; Khoury, H. J.; Elihimas, D. R., E-mail: msantiag@exa.unicen.edu.ar [Universidade Federal de Pernambuco, Departamento de Energia Nuclear, Av. Prof. Luiz Freire 1000, Recife, PE 50740-540 (Brazil)

2011-10-15

Carbon-doped aluminum oxide (Al{sub 2}O{sub 3}:C) is one of the most used radioluminescence (Rl) materials for fiberoptic dosimetry due to its high efficiency and commercial availability. However, this compound presents the drawback of emitting in the spectral region, where the spurious radioluminescence of fibers is also important. In this work, the radioluminescence response of rare-earth doped Al{sub 2}O{sub 3} samples has been evaluated. The samples were prepared by mixing stoichiometric amounts of aluminum nitrate, urea and dopants with different amounts of terbium, samarium, cerium and thulium nitrates varying from 0 to 0.15 mo 1%. The influence of the different activators on the Rl spectra has been investigated in order to determine the feasibility of using these compounds for Rl fiberoptic dosimetry. (Author)

Radioluminescence of rare-earth doped aluminum oxide

International Nuclear Information System (INIS)

Santiago, M.; Molina, P.; Barros, V. S.; Khoury, H. J.; Elihimas, D. R.

2011-10-01

Carbon-doped aluminum oxide (Al 2 O 3 :C) is one of the most used radioluminescence (Rl) materials for fiberoptic dosimetry due to its high efficiency and commercial availability. However, this compound presents the drawback of emitting in the spectral region, where the spurious radioluminescence of fibers is also important. In this work, the radioluminescence response of rare-earth doped Al 2 O 3 samples has been evaluated. The samples were prepared by mixing stoichiometric amounts of aluminum nitrate, urea and dopants with different amounts of terbium, samarium, cerium and thulium nitrates varying from 0 to 0.15 mo 1%. The influence of the different activators on the Rl spectra has been investigated in order to determine the feasibility of using these compounds for Rl fiberoptic dosimetry. (Author)

White- and blue-light-emitting dysprosium(III) and terbium(III)-doped gadolinium titanate phosphors.

Science.gov (United States)

Antić, Ž; Kuzman, S; Đorđević, V; Dramićanin, M D; Thundat, T

2017-06-01

Here we report the synthesis and structural, morphological, and photoluminescence analysis of white- and blue-light-emitting Dy 3 + - and Tm 3 + -doped Gd 2 Ti 2 O 7 nanophosphors. Single-phase cubic Gd 2 Ti 2 O 7 nanopowders consist of compact, dense aggregates of nanoparticles with an average size of ~25 nm for Dy 3 + -doped and ~50 nm for Tm 3 + -doped samples. The photoluminescence results indicated that ultraviolet (UV) light excitation of the Dy 3 + -doped sample resulted in direct generation of white light, while a dominant yellow emission was obtained under blue-light excitation. Intense blue light was obtained for Tm 3 + -doped Gd 2 Ti 2 O 7 under UV excitation suggesting that this material could be used as a blue phosphor. Copyright © 2016 John Wiley & Sons, Ltd.

Semiconductor composition containing iron, dysprosium, and terbium

Science.gov (United States)

Pooser, Raphael C.; Lawrie, Benjamin J.; Baddorf, Arthur P.; Malasi, Abhinav; Taz, Humaira; Farah, Annettee E.; Kalyanaraman, Ramakrishnan; Duscher, Gerd Josef Mansfred; Patel, Maulik K.

2017-09-26

An amorphous semiconductor composition includes 1 to 70 atomic percent iron, 15 to 65 atomic percent dysprosium, 15 to 35 atomic percent terbium, balance X, wherein X is at least one of an oxidizing element and a reducing element. The composition has an essentially amorphous microstructure, an optical transmittance of at least 50% in at least the visible spectrum and semiconductor electrical properties.

Characterization of mixed-conducting barium cerate-based perovskites for potential fuel cell applications

Science.gov (United States)

Mukundan, R.

Chemical modifications of barium cerium gadolinium oxide through the substitution of Bi, Tb, Pr, Nb and Ta were attempted in an effort to increase the p-type or n-type conductivity, and to develop new mixed-conducting electrodes that are chemically compatible with the Ba(Cesb{1-x}Gdsb{x})Osb{3-x/2} electrolyte. The structure, oxygen non-stoichiometry, electronic and ionic-conductivity of several compositions in the doped-barium cerate systems were studied by X-ray diffraction, TGA, DC and AC conductivity, and EMF measurements. The cathodic overpotential of the mixed (electronic/ionic) conducting compositions in this system, on a Ba(Cesb{0.8}Gdsb{0.2})Osb{2.9} electrolyte, were also studied using Current Interruption and AC impedance techniques. The substitution of Bi into Ba(Cesb{0.9}Gdsb{0.1})Osb{2.95} lead to a significant increase in the electronic conductivity, and a total conductivity of about 0.94 S/cm was obtained for Ba(Bisb{0.5}Cesb{0.4}Gdsb{0.1})Osb3 at 800sp°C in air. However, the concentration of oxygen-ion vacancies and hence the ionic conductivity decreased due to the oxidation of Bi to the 5sp{+} state. Compositions in the Ba(Bisb{0.5}Cesb{x}Gdsb{0.5-x})Osb3 system also exhibited significant oxygen non-stoichiometry depending upon the ordering of the B-site cations and the relative concentrations of Ce and Gd. However, the absence of any detectable EMF in the non-stoichiometric compositions implied that the oxygen vacancies are strongly associated with the Bisp{3+} cations. Although highly conductive, chemically stable compositions were prepared in the Ba(Bisb{x}Cesb{y}Gdsb{1-(x+y)})Osb{3-d} system, their ionic conductivities were low. The mixed-conduction properties of Ba(Cesb{1-x}Gdsb{x})Osb{3-d} were enhanced under cathode conditions (600-800sp°C in air) by the substitution of Ce by Tb and Pr. While the substitution of Tb resulted in a decrease in the total conductivity, Pr induced a significant increase in the total conductivity at high Pr

Low-temperature thermal conductivity of terbium-gallium garnet

International Nuclear Information System (INIS)

Inyushkin, A. V.; Taldenkov, A. N.

2010-01-01

Thermal conductivity of paramagnetic Tb 3 Ga 5 O 12 (TbGG) terbium-gallium garnet single crystals is investigated at temperatures from 0.4 to 300 K in magnetic fields up to 3.25 T. A minimum is observed in the temperature dependence κ(T) of thermal conductivity at T min = 0.52 K. This and other singularities on the κ(T) dependence are associated with scattering of phonons from terbium ions. The thermal conductivity at T = 5.1 K strongly depends on the magnetic field direction relative to the crystallographic axes of the crystal. Experimental data are considered using the Debye theory of thermal conductivity taking into account resonance scattering of phonons from Tb 3+ ions. Analysis of the temperature and field dependences of the thermal conductivity indicates the existence of a strong spin-phonon interaction in TbGG. The low-temperature behavior of the thermal conductivity (field and angular dependences) is mainly determined by resonance scattering of phonons at the first quasi-doublet of the electron spectrum of Tb 3+ ion.

Automated spectrofluorimetric determinations of terbium and dysprosium in rare earth mixtures

Energy Technology Data Exchange (ETDEWEB)

Lyle, S.J.; Za' tar, N. (Kent Univ., Canterbury (UK))

1983-12-01

Several methods involving the use of water-soluble binary and ternary complexes have been proposed for the spectrofluorimetric determination based on terbium(III) emission at 545 nm. These are terbium(III) with (A) ethylenediamine-N,N'-bis(o-hydroxyphenylacetic acid), (B) o-hydroxyphenyliminodiacetic acid, (C) EDTA + 5-sulphosalicylic acid, (D) EDTA + 1,2-dihydroxybenzene-3,5-disulphonic acid disodium salt (Tiron), and (E) iminodiacetic acid (IDA) + Tiron. Two of the reagent mixtures (D and E) can also be used for the fluorimetric determination of dysprosium(III) at 582 nm. A comparison has been made of these methods in order to select the most satisfactory procedure with respect to selectivity, sensitivity and suitability for adaption to automatic operation. Results are given and discussed.

Fluorescence yield in rare-earth-doped sol-gel silicate glasses

Energy Technology Data Exchange (ETDEWEB)

Silversmith, A.J., E-mail: asilvers@hamilton.ed [Physics Department, Hamilton College, 198 College Hill Road, Clinton, NY 13323 (United States); Nguyen, Nguyen T.T.; Campbell, D.L. [Physics Department, Hamilton College, 198 College Hill Road, Clinton, NY 13323 (United States); Boye, D.M.; Ortiz, C.P. [Davidson College, Davidson, NC 28035 (United States); Hoffman, K.R. [Whitman College, Walla Walla, WA 99362 (United States)

2009-12-15

We have used trivalent terbium to investigate the mechanism behind fluorescence enhancement by Al{sup 3+} co-doping. Our results indicate that rare-earth (RE) ions cluster together in aluminum-rich regions of the glass, and behave as if they were dispersed uniformly throughout these regions when the ratio of Al to RE is {approx}10 or greater. We also studied the effects of adding chemical drying agents to the precursor solution for the synthesis of sol-gel-derived silicate glasses. Such glasses can be treated at significantly higher annealing temperatures without degradation of optical quality, and have the density of melt glass. Fluorescence yield from doped RE ions improves markedly with the addition of the drying agents, and the denser glasses are not subject to rehydration.

Characterization of antibody-chelator conjugates: Determination of chelator content by terbium fluorescence titration

Energy Technology Data Exchange (ETDEWEB)

Brandt, K.D.; Schnobrich, K.E.; Johnson, D.K. (Abbott Laboratories, Department 90M, Abbott Park, IL (United States))

1991-01-01

Fluorescence titrations were performed by adding varying mole ratios of terbium(III) to antibody conjugates formed by benzyl isothiocyanate derivatives of three different polyaminopolycarboxylate chelators (NTA, EDTA, and DTPA) and the results compared to values for average chelator content obtained by cobalt-57 binding assays. For two different murine monoclonal antibodies, the average chelator content obtained by terbium fluorescence titration correlated closely with that measured by the cobalt-57 binding assay. It is concluded that lanthanide fluorescence titrations provide a useful alternative to radiometal binding assays for the determination of chelator content in protein-chelator conjugates.

Characterization of antibody-chelator conjugates: Determination of chelator content by terbium fluorescence titration

International Nuclear Information System (INIS)

Brandt, K.D.; Schnobrich, K.E.; Johnson, D.K.

1991-01-01

Fluorescence titrations were performed by adding varying mole ratios of terbium(III) to antibody conjugates formed by benzyl isothiocyanate derivatives of three different polyaminopolycarboxylate chelators (NTA, EDTA, and DTPA) and the results compared to values for average chelator content obtained by cobalt-57 binding assays. For two different murine monoclonal antibodies, the average chelator content obtained by terbium fluorescence titration correlated closely with that measured by the cobalt-57 binding assay. It is concluded that lanthanide fluorescence titrations provide a useful alternative to radiometal binding assays for the determination of chelator content in protein-chelator conjugates

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

X-ray fluorescence analysis of terbium oxide for rare earth impurities

International Nuclear Information System (INIS)

Chandola, L.C.; Machado, I.J.; Mohile, A.N.

1975-01-01

A method for the determination of Sm 2 O 3 , Eu 2 O 3 , Gd 2 O 3 , Dy 2 O 3 , Ho 2 O 3 and Y 2 O 3 in terbium oxide is described. The sample is converted to terbium oxalate, mixed with boric acid binder in the ratio 2:1, pelleted at a pressure of 20 tons over a boric acid backing pellet and irradiated with x-rays from a tungsten tube operated by Philips PW 1140 generator. The secondary x-rays thus generated are analysed by a LiF (200) crystal in Philips PW 1220 x-ray fluorescence spectrometer using suitable detectors. The minimum determination limit (MDL) is 0.01% for all rare earth oxides determined except for Y 2 O 3 for which it is 0.005%. (author)

Fluorescence enhancement of samarium complex co-doped with terbium complex in a poly(methyl methacrylate) matrix

International Nuclear Information System (INIS)

Jiu Hongfang; Zhang Lixin; Liu Guode; Fan Tao

2009-01-01

The fluorescence property of Sm(DBM) 3 phen- (DBM-dibenzoylmethide, phen-1,10-phenanthroline) and Tb(DBM) 3 phen-co-doped poly(methyl methacrylate) (PMMA) was investigated. The excitation, emission spectra and fluorescence lifetime of the co-doped samples were examined. In the co-doped samples, the luminescence intensities of Sm 3+ enhance with an increase of the Tb(DBM) 3 phen content and with a decrease of the Sm(DBM) 3 phen content. The reason for the fluorescence enhancement effect in the co-doped polymer is the intermolecular energy transfer. To give a vivid picture for this co-doped system, a model for the fluorescence enhancement of Sm(DBM) 3 phen- and Tb(DBM) 3 phen-co-doped PMMA is presented

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

Investigation of terbium scandate as an alternative gate dielectric in fully depleted transistors

Science.gov (United States)

Roeckerath, M.; Lopes, J. M. J.; Özben, E. Durǧun; Urban, C.; Schubert, J.; Mantl, S.; Jia, Y.; Schlom, D. G.

2010-01-01

Terbium scandate thin films were deposited by e-gun evaporation on (100) silicon substrates. Rutherford backscattering spectrometry and x-ray diffraction studies revealed homogeneous chemical compositions of the films. A dielectric constant of 26 and CV-curves with small hystereses were measured as well as low leakage current densities of <1 nA/cm2. Fully depleted n-type field-effect transistors on thin silicon-on-insulator substrates with terbium scandate gate dielectrics were fabricated with a gate-last process. The devices show inverse subthreshold slopes of 80 mV/dec and a carrier mobility for electrons of 225 cm2/V•s was extracted.

Study of effect of radiation on the parameters of quality of sterile males of Ceratitis Ceratitis capitata (Wied.) and their improvement aroma therapy

International Nuclear Information System (INIS)

Nouira, Manel

2008-01-01

In this present work, we are interested in studying the various stages in the production of sterile males, the effect of different doses of irradiation on longevity, compatibility and competitiveness of these males. And the effect of exposure of adults and pupae of Ceratitis to different doses of essential oil of ginger on their compatibility and competitiveness. (Author)

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...

Solution growth of Tb doped Gd_2O_3 film

International Nuclear Information System (INIS)

Ghosh, M.; Pitale, S.; Desai, D.G.; Patra, G.D.; Sen, S.; Gadkari, S.C.

2016-01-01

Nanomaterials of Gd_2O_3 have proven applications in medical imaging and cancer therapy due to the presence of element Gd. Also Gd_2O_3 films have been grown by vapor phase method as well as self assembly in solution and studied as a high-k dielectric and efficient luminescence material. Here, we report a method to obtain Tb doped Gd_2O_3 film by solution growth method followed by suitable heat treatment. Uniform films of Tb doped Gadolinium hydroxycarbonate have been deposited on fused quartz substrates kept inside a solution containing gadolinium nitrate, terbium nitrate and Urea maintained at 90°C. Gadolinium hydroxy-carbonate films are then treated at 800°C for 2 hour to obtain Tb doped cubic Gd_2O_3 as confirmed by X-ray diffraction measurement. The photoluminescence spectra display characteristic Tb emission at 544 nm when excited at 285 nm. The lifetime of Tb emission is found to be of the order of few microseconds. (author)

Magneto-optical studies of valence instability in europium and terbium phosphors

Czech Academy of Sciences Publication Activity Database

Rodrigues, L.C.v.; Hölsä, J.; Brito, H.F.; Maryško, Miroslav; Matos, J.R.; Paturi, P.; Rodrigues, R.V.; Lastusaari, M.

2016-01-01

Roč. 170, Feb (2016), 701-706 ISSN 0022-2313 Institutional support: RVO:68378271 Keywords : valence * europium * terbium * oxysulfide and -sulfate * phosphors * paramagnetic susceptibility Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.686, year: 2016

Analysis of the Ceratitis capitata y chromosome using in situ hybridization to mitotic chromosomes

International Nuclear Information System (INIS)

Willhoeft, U.; Franz, G.

1998-01-01

In Ceratitis capitata the Y chromosome is responsible for sex-determination. We used fluorescence in situ hybridization (FISH) for cytogenetic analysis of mitotic chromosomes. FISH with the wild-type strain EgyptII and two repetitive DNA probes enabled us to differentiate between the short and the long arm of the Y chromosome and gives a much better resolution than C-banding of mitotic chromosomes. We identified the Y-chromosomal breakpoints in Y-autosome translocations using FISH. Even more complex rearrangements i.e. deletions and insertions in some translocation strains were detected by this method. A strategy for mapping the primary sex determination factor in Ceratitis capitata by FISH is presented. (author)

Cross sections from 800 MeV proton irradiation of terbium

Energy Technology Data Exchange (ETDEWEB)

Engle, J.W., E-mail: jwengle@lanl.gov [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Mashnik, S.G.; Bach, H.; Couture, A.; Jackman, K.; Gritzo, R.; Ballard, B.D.; Fassbender, M.; Smith, D.M.; Bitteker, L.J.; Ullmann, J.L.; Gulley, M.S.; Pillai, C.; John, K.D.; Birnbaum, E.R. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Nortier, F.M., E-mail: meiring@lanl.gov [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

2012-11-02

Terbium foils were irradiated with 800 MeV protons to ascertain the potential for production of lanthanide isotopes of interest in medical, astrophysical, and basic science research and to contribute to nuclear data repositories. Isotopes produced in the foil were quantified by gamma spectroscopy. Cross sections for 35 isotopes produced in the irradiation are reported and compared with predictions by the MCNP6 transport code using the CEM03.03, Bertini and INCL + ABLA event generators. Our results indicate the need to accurately consider fission and fragmentation of relatively light target nuclei like terbium in the modeling of nuclear reactions at 800 MeV. The predictive power of the code was found to be different for each event generator tested but was satisfactory for most of the product yields in the mass region where spallation reactions dominate. However, none of the event generators' results are in complete agreement with measured data.

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.

Interaction of terbium group metal oxides with carbon

International Nuclear Information System (INIS)

Vodop'yanov, A.G.; Baranov, S.V.; Kozhevnikov, G.N.

1990-01-01

Mechanism of carbothermal reduction of terbium group metals from oxides is investigated using thermodynamic and kinetic analyses. Interaction of metal oxides with carbon covers dissociation of metal oxides and reduction by carbon monoxide, which contribution into general reduction depends on CO pressure. Temperatures of reaction beginning for batch initial components at P=1.3x10 -4 and P CO =0.1 MPa and of formation of oxycarbide melts are determined

Tritium conductivity and isotope effect in proton-conducting perovskites

International Nuclear Information System (INIS)

Mukundan, R.; Brosha, E.L.; Birdsell, S.A.; Costello, A.L.; Garzon, F.H.; Willms, R.S.

1999-01-01

The tritium ion conductivities of SrZr 0.9 Yb 0.1 O 2.95 and BaCe 0.9 Yb 0.1 O 2.95 have been measured by ac impedance analysis. The high tritium conductivity of these perovskites could potentially lead to their application as an electrochemical membrane for the recovery of tritium from tritiated gas streams. The conductivities of these perovskites, along with SrCe 0.95 Yb 0.05 O 2.975 , were also measured in hydrogen- and deuterium-containing atmospheres to illustrate the isotope effect. For the strontium zirconate and barium cerate samples, the impedance plot consists of two clearly resolved arcs, a bulk and a grain boundary arc, in the temperature range 50--350 C. However, for the strontium cerate sample, the clear resolution of the bulk conductivity was not possible and only the total conductivity was measurable. Thus, the isotope effect was clearly established only for the strontium zirconate and barium cerate samples. The decrease in bulk conductivity with increasing isotope mass was found to be a result of an increase in the activation energy for conduction accompanied by a decrease in the pre-exponential factor. Since the concentration of the mobile species (H+, D+, or T+) should remain relatively constant at T < 350 C, this increase in activation energy is directly attributable to the increased activation energy for the isotope mobility

Terbium oxide at high pressures

International Nuclear Information System (INIS)

Dogra, Sugandha; Sharma, Nita Dilawar; Singh, Jasveer; Bandhyopadhyay, A.K.

2011-01-01

In this work we report the behaviour of terbium oxide at high pressures. The as received sample was characterized at ambient by X-ray diffraction and Raman spectroscopy. The X-ray diffraction showed the sample to be predominantly cubic Tb 4 O 7 , although a few peaks also match closely with Tb 2 O 3 . In fact in a recent study done on the same sample, the sample has been shown to be a mixture of Tb 4 O 7 and Tb 2 O 3 . The sample was subjected to high pressures using a Mao-Bell type diamond anvil cell upto a pressure of about 42 GPa with ruby as pressure monitor

Terbium(III) ions as sensitizers of oxidation of indole and its derivatives in Fenton system

Energy Technology Data Exchange (ETDEWEB)

Kaczmarek, Małgorzata, E-mail: mkaczmar@amu.edu.pl; Staninski, Krzysztof

2017-03-15

Oxidation of indole and its derivatives in the Fenton system as a source of oxidising agents, in the presence of terbium(III) ions was studied by chemiluminescence methods to get the kinetic curves of emission decay and spectral distributions of chemiluminescence. Terbium(III) ions acted as a sensitizer of the mixtures Tb(III)-Fe(II)/Fe(III)-H{sub 2}O{sub 2}-indole or its derivative (tryptophan, tryptamine, indole-3-acetic acid and indole-3-acetyl aspartic acid). For the above indolic compounds, linear dependencies of integrated intensity of chemiluminescence on concentration of indolic compound in water and in water-acetonitrile solution were obtained. The limits of detection (LOD) and quantification (LOQ) of the indolic compounds studied were found to be by one or two orders of magnitude lower in the system with terbium(III) ions than without them. - Highlights: • Chemiluminescence emitted on oxidation of indolic compounds in Fenton system. • Tb (III) ions as sensitizers of indolic compounds oxidation in solutions. • Linear relations between CL intensity and indolic compound concentration.

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)

Synthesis and characterization of Tin / Titanium mixed oxide nanoparticles doped with lanthanide for biomarking; Sintese e caracterizacao de nanoparticulas de oxido misto de estanho/titanio dopadas com lantanideos para marcacao biologica

Energy Technology Data Exchange (ETDEWEB)

Paganini, Paula Pinheiro

2012-07-01

This work presents the synthesis, characterization and photo luminescent study of tin and titanium mixed oxide nanoparticles doped with europium, terbium and neodymium to be used with luminescent markers on biological systems. The syntheses were done by co-precipitation, protein sol-gel and Pechini methods and the nanoparticles were characterized by infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, X-ray diffraction and X-ray absorption spectroscopy. The photo luminescent properties studies were conducted for luminophores doped with europium, terbium and neodymium synthesized by coprecipitation method. For luminophore doped with europium it was possible to calculate the intensity parameters and quantum yield and it showed satisfactory results. In the case of biological system marking it was necessary the functionalization of these particles to allow them to bind to the biological part to be studied. So the nanoparticles were functionalized by microwave and Stoeber methods and characterized by infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction obtaining qualitative response of functionalization efficacy. The ninhydrin spectroscopic method was used for quantification of luminophores functionalization. The photo luminescent studies of functionalized particles demonstrate the potential applying of these luminophores as luminescent markers. (author)

Complex compounds of terbium(III) with some nonsteroidal anti-inflammatory drugs and their analytical applications

International Nuclear Information System (INIS)

Teslyuk, O.I.; Egorova, A.V.; Yagodkin, B.N.; Bel'tyukova, S.V.

2007-01-01

Luminescence properties of the complexes of terbium(III) with nonsteroidal anti-inflammatory drugs (ibuprofen and orthofen) were studied. It was demonstrated that in the presence of organic bases (2,2'-dipyridyl and 1,10-phenanthroline) mixed-ligand complexes are formed and the luminescence intensity of terbium(III) increases by a factor of up to 250. The optimum complexation conditions were determined. It was proposed to use these complexes as analytical forms for the luminescence determination of nonsteroidal anti-inflammatory drugs (ibuprofen and orthofen) in pharmaceutical dosage forms. The detection limits are 2 and 0.05 μg/ml, respectively [ru

The temperature dependence of thermooptical properties of magnetooptical TAG ceramics doped with silicon and titanium

Science.gov (United States)

Starobor, Aleksey; Palashov, Oleg

2018-04-01

Thermal effects in terbium aluminum garnet (TAG) ceramics (thermal lens and thermally induced depolarization) doped with silicon and titanium were investigated in temperature range of 79-293K. Samples with low dopant concentrations shows decreasing of negative thermal effects with cooling to 79 K. However for most part of samples thermal depolarization starts increasing after initial decreasing with cooling. Apparently it is connected with defects in media. Best sample (0.4 at% of Si) as pure TAG shows monotonous decreasing of thermally induced depolarization and 3.5 times Verdet constant increasing with cooling to 79 K, that leads to 1.8-times advantage over common magnetooptical media - terbium gallium garnet. It allows to provide an isolation of 30 dB at a radiation power of more than 6 kW as estimated. However, the procedure for creating ceramics samples obviously needs improvement because of the large scatter in the quality of the samples.

Genetic markers, translocations and sexing genes on chromosome 2 of Ceratitis capitata

International Nuclear Information System (INIS)

Cladera, J.L.

1997-01-01

A review is presented of results obtained in a search for genetic markers, translocations and selectable genes obtained at the Instituto de Genetica, Castelar, Argentina, with special reference to chromosome 2 linked mutations and genes useful for developing self-sexing strains in Ceratitis capitata. (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)

Wing morphometrics as a possible tool for the diagnosis of the Ceratitis fasciventris, C. anonae, C. rosa complex (Diptera, Tephritidae).

Science.gov (United States)

Van Cann, Joannes; Virgilio, Massimiliano; Jordaens, Kurt; De Meyer, Marc

2015-01-01

Previous attempts to resolve the Ceratitis FAR complex (Ceratitis fasciventris, Ceratitis anonae, Ceratitis rosa, Diptera, Tephritidae) showed contrasting results and revealed the occurrence of five microsatellite genotypic clusters (A, F1, F2, R1, R2). In this paper we explore the potential of wing morphometrics for the diagnosis of FAR morphospecies and genotypic clusters. We considered a set of 227 specimens previously morphologically identified and genotyped at 16 microsatellite loci. Seventeen wing landmarks and 6 wing band areas were used for morphometric analyses. Permutational multivariate analysis of variance detected significant differences both across morphospecies and genotypic clusters (for both males and females). Unconstrained and constrained ordinations did not properly resolve groups corresponding to morphospecies or genotypic clusters. However, posterior group membership probabilities (PGMPs) of the Discriminant Analysis of Principal Components (DAPC) allowed the consistent identification of a relevant proportion of specimens (but with performances differing across morphospecies and genotypic clusters). This study suggests that wing morphometrics and PGMPs might represent a possible tool for the diagnosis of species within the FAR complex. Here, we propose a tentative diagnostic method and provide a first reference library of morphometric measures that might be used for the identification of additional and unidentified FAR specimens.

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.)

A new diagnostic resource for Ceratitis capitata strain identification based on QTL mapping

Science.gov (United States)

The Mediterranean fruit fly Ceratitis capitata(Wiedemann), or medfly, is a destructive agricultural pest and the subject of exclusion efforts in many countries. Suppression and eradication of invasive populations to prevent establishment is facilitated by the release of sterile males using the steri...

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)

A terbium(III)-organic framework for highly selective sensing of cytidine triphosphate.

Science.gov (United States)

Zhao, Xi Juan; He, Rong Xing; Li, Yuan Fang

2012-11-21

Highly selective sensing of cytidine triphosphate (CTP) against other triphosphate nucleosides including ATP, GTP and UTP is successfully achieved with a luminescent terbium(III)-organic framework (TbOF) of [Tb(2)(2,3-pzdc)(2)(ox)(H(2)O)(2)](n) (2,3-pzdc(2-) = 2,3-pyrazinedicarboxylate, ox(2-) = oxalate).

Circularly photostimulated electrogyration in europium- and terbium-doped GaN nanocrystals embedded in a silica xerogel matrix

International Nuclear Information System (INIS)

Kityk, I V; Nyk, M; Strek, W; Jablonski, J M; Misiewicz, J

2005-01-01

Circularly polarized optical poling was proposed and discovered for GaN nanocrystallites embedded in a silica xerogel matrix. The method consists of the creation of screw-like polarization of the medium during the interaction of two circularly polarized coherent bicolour beams. It was shown that doping of the GaN nanocrystallites by Tb 3+ and Eu 3+ ions leads to substantial enhancement of the electrogyration. The effect observed is a consequence of the superposition of nanoconfined effects and the contribution of the localized rare-earth 4f levels. The role of the anharmonic electron-phonon interaction is discussed. The photoluminescence and cathodoluminescence spectra of the GaN composites were investigated. It was demonstrated that the Eu-doped nanocrystallites give a substantially higher effect of the electrogyration compared to the Tb-doped and non-doped ones

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.

Syntheses of optically efficient (La{sub 1-x-y}Ce{sub x}Tb{sub y})F{sub 3} nanocrystals via a hydrothermal method

Energy Technology Data Exchange (ETDEWEB)

Wang Qiang [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States); You Yumin; Ludescher, Richard D. [Department of Food Science, Rutgers University, New Brunswick, NJ 08901 (United States); Ju Yiguang, E-mail: yju@princeton.ed [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States)

2010-06-15

Optically efficient cerium and terbium doped lanthanide fluoride (La{sub 1-x-y}Ce{sub x}Tb{sub y})F{sub 3} nanocrystals with different doping concentrations have been synthesized by a hydrothermal route in the presence of ethylenediamine tetraacetic acid disodium salt (EDTA). The results showed that the formation of nanocrystals with different morphologies depends on terbium ion Tb{sup 3+} doping concentration, but independent of cerium ion Ce{sup 3+} doping concentration. With increase in Tb{sup 3+} doping concentration, the morphologies of nanocrystals evolved from a spherical shape to a plated-like one. In addition, both the photoluminescence quantum yield (PL QY) and the fluorescence lifetime of nanocrystals increased with the increase in Ce{sup 3+} doping concentration in cerium and terbium co-doped system. The PL QY reached up to 55%, and the lifetime up to 7.3 ms. Transmission electron microscopy (TEM), X-ray diffraction (XRD), selected area electron diffraction (SAED), X-ray fluorescence (XRF), energy dispersive spectroscopy (EDS), ultraviolet-visible (UV-vis) absorption, photoluminescence (PL) and infrared (IR) spectroscopies were employed to characterize the properties of nanocrystals. The growth mechanism of nanocrystals with different morphologies and optical properties of nanocrystals with different doping concentrations were investigated.

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)

Raman spectra of terbium trichloride, phosphorus pentachloride and their molten mixtures

International Nuclear Information System (INIS)

Salyulev, A.B.; Zakir'yanova, I.D.

2008-01-01

Raman spectroscopy was used to study in situ the behavior of individual terbium trichloride and phosphorus pentachloride in different aggregative states as a function of temperature, and of solutions of PCl 5 vapors in molten TbCl 3 . A conclusion is drawn about their structure and the nature of phase transformations and chemical reactions in wide ranges of temperature and saturated vapor pressures [ru

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.

Perovskite solid electrolytes: Structure, transport properties and fuel cell applications

DEFF Research Database (Denmark)

Bonanos, N.; Knight, K.S.; Ellis, B.

1995-01-01

Doped barium cerate perovskites, first investigated by Iwahara and co-workers, have ionic conductivities of the order of 20 mS/cm at 800 degrees C making them attractive as fuel cell electrolytes for this temperature region. They have been used to construct laboratory scale fuel cells, which...... vapour transfer in a cell in which the perovskite is exposed to wet hydrogen on both sides. The evolution of transport properties with temperature is discussed in relation to structure. Neutron diffraction studies of doped and undoped barium cerate are reported, revealing a series of phase transitions...... between ambient temperature and 1000 degrees C. The available literature on chemical stability of cerate perovskites to reduction and attack by carbon dioxide is reviewed in brief....

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.

Efficient green luminescence of terbium oxalate crystals: A case study with Judd-Ofelt theory and single crystal structure analysis and the effect of dehydration on luminescence

Science.gov (United States)

Alexander, Dinu; Joy, Monu; Thomas, Kukku; Sisira, S.; Biju, P. R.; Unnikrishnan, N. V.; Sudarsanakumar, C.; Ittyachen, M. A.; Joseph, Cyriac

2018-06-01

Design and synthesis of Lanthanide based metal organic framework is a frontier area of research owing to their structural diversity enabling specific applications. The luminescence properties of rare earths, tuned by the structural features of Ln-MOFs are investigated extensively. Rare earth oxalates which can be synthesized in a facile method, ensuring the structural features of MOFs with excellent photoluminescence characteristics deserves much attention. This work is the first time report on the single crystal structure and Judd-Ofelt (JO) theoretical analysis - their correlation with the intense and sharp green luminescence of Terbium oxalate crystals. The intense green luminescence observed for Terbium oxalate crystals for a wide range of excitation from DUV to visible region despite the luminescence limiting factors are discussed. The absence of concentration quenching and lifting up of forbidden nature of f-f transitions, allowing direct excitation of Terbium ions is analysed with the help of JO theory and single crystal structure analysis. The JO analysis predicted the asymmetry of Terbium sites, allowing the electric dipole transitions and from the JO intensity parameters, promising spectroscopic parameters - emission cross section, branching ratio, gain band width and gain coefficient of the material were calculated. The single crystal structure analysis revealed the asymmetry of Tb sites and structure of Terbium oxalate is formed by the hydrogen bonded stacking of overlapped six Terbium membered rings connected by the oxalate ligands. The molecularly thick layers thus formed on the crystal surface are imaged by the atomic force microscopy. The presence of water channels in the structure and the effect of lattice water molecules on the luminescence intensity are also investigated.

Infestation of grape Vitis vinifera by Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) in sub-medium Sao Francisco valley, Brazil

Energy Technology Data Exchange (ETDEWEB)

Habibe, Tuffi C.; Viana, Rodrigo E.; Damasceno, Itala Cruz; Malavasi, Aldo [Biofabrica Moscamed Brasil, Juazeiro, BA (Brazil). Distrito Industrial do Sao Francisco; Nascimento, Antonio S., E-mail: antnasc@cnpmf.embrapa.b [EMBRAPA Mandioca e Fruticultura Tropical, Cruz das Almas, BA (Brazil); Paranhos, Beatriz A.J.; Haji, Francisca Nemaura P., E-mail: bjodao@cpatsa.embrapa.b [EMBRAPA Semi-Arido, Petrolina, PE (Brazil); Carvalho, Raimundo S. [Agencia de Defesa Agropecuaria da Bahia (ADAB), Salvador, BA (Brazil)

2006-07-01

The objective of this study was to assess the infestation level in grapes, Vitis vinifera, by the medfly,Ceratitis capitata in the Sao Francisco River Valley. The adult population was monitored with Jackson trap baited with trimedlure. Samples of grapes for larval infestation assessment were taken along three months, with a total of 116 kg. The average FTD (flies/trap/day) for medfly males was 0.26. The number of pupae obtained from the fruit samples was 471; 287 adults emerged (60.4%), all Ceratitis capitata. The infestation level was 4.0 pupa/kg of fresh fruit. We conclude that grape is a medfly host in SFV, occasionally causing high damage to production. (author)

Infestation of grape Vitis vinifera by Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) in sub-medium Sao Francisco valley, Brazil

International Nuclear Information System (INIS)

Habibe, Tuffi C.; Viana, Rodrigo E.; Damasceno, Itala Cruz; Malavasi, Aldo; Paranhos, Beatriz A.J.; Haji, Francisca Nemaura P.; Carvalho, Raimundo S.

2006-01-01

The objective of this study was to assess the infestation level in grapes, Vitis vinifera, by the medfly,Ceratitis capitata in the Sao Francisco River Valley. The adult population was monitored with Jackson trap baited with trimedlure. Samples of grapes for larval infestation assessment were taken along three months, with a total of 116 kg. The average FTD (flies/trap/day) for medfly males was 0.26. The number of pupae obtained from the fruit samples was 471; 287 adults emerged (60.4%), all Ceratitis capitata. The infestation level was 4.0 pupa/kg of fresh fruit. We conclude that grape is a medfly host in SFV, occasionally causing high damage to production. (author)

Pos-harvest control of Ceratitis capitata (Wiedemann, 1824) (Diptera: Tephritidae) in guava fruits (Psidium guajava L.).; Controle pos-colheita de Ceratitis capitata (Wiedemann, 1824) (Diptera: Tephritidae) em frutos de goiaba (Psidium guajava L.)

Energy Technology Data Exchange (ETDEWEB)

Doria, Hayda Oliveira Souza

2006-07-01

The objective of this work is to evaluate the effect of the treatment with steam heating, hot water and gamma radiation of Co-60 on eggs and fruit flies larvae (Ceratitis capitata Wiedemann, 1824) (Diptera: Tephritidae), and analyze the effect of these treatments in the fruit quality (chemical composition)

Spectrofluorimetric determination of cefixime using terbium-danofloxacin probe

Directory of Open Access Journals (Sweden)

Jamshid L Manzoori

2014-04-01

Full Text Available Objective(s:Cefixime (Cfx, is a semi-synthetic third-generation oral cephalosporin antibiotic that is prescribed for the treatment of susceptible infections. There are some procedures for the determination of Cfx in pharmaceutical formulations and biological samples. Herein a spectrofluorimetric method was proposed for Cfx determination based on the fluorescence quenching of terbium-danofloxacin (Tb3+-Dano in the presence of Cfx. Materials and Methods: Cfx was detected based on fluorescence quenching of terbium-danofloxacin (Tb3+-Dano in the presence of Cfx with maximum excitation and emission wavelengths at 347 nm and 545 nm, respectively. The quenched fluorescence intensity of Tb3+- Dano system is proportional to the concentration of Cfx. The optimum conditions for the determination of Cfx were studied. Results: The maximum response was achieved under optimum conditions of [Tris buffer]= 0.008 mol/l (pH 6.5, [Tb3+]=1×10-4 mol/l  and [Dano]=1×10-4 mol/l. The developed method was evaluated in terms of accuracy, precision and limit of detection. The linear concentration ranges for quantification of Cfx were 8.8×10-8-8.8×10-7 mol/l and 1.1×10-7-8.8×10-7 mol/l in standard and human serum samples with the detection limits (S/N=3 of 2.8×10-8 mol/l and 3.9×10-8 mol/l, respectively. The Cfx was determined in pharmaceutical tablets and spiked serum samples and the results were satisfactory.   Conclusion: This method is simple, practical and relatively interference-free for determination of Cfx in pharmaceutical tablets and serum samples.

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.

First record of Ceratitis capitata (Wiedemann (Diptera: Tephritidae in the state of Acre, Brazil

Directory of Open Access Journals (Sweden)

Ricardo Adaime

2017-12-01

Resumo. Registra-se pela primeira vez a presença de Ceratitis capitata (Wiedemann (Diptera: Tephritidae no estado do Acre, Brasil, a partir de frutos de goiabeira (Psidium guajava L. e de caramboleira (Averrhoacarambola L., aumentando o conhecimento dos registros geográficos dessa mosca na Amazônia brasileira.

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 fluoxetine in pharmaceutical and biological samples based on the silver nanoparticle enhanced fluorescence of fluoxetine-terbium complex.

Science.gov (United States)

Lotfi, Ali; Manzoori, Jamshid L

2016-11-01

In this study, a simple and sensitive spectrofluorimetric method is presented for the determination of fluoxetine based on the enhancing effect of silver nanoparticles (AgNPs) on the terbium-fluoxetine fluorescence emission. The AgNPs were prepared by a simple reduction method and characterized by UV-Vis spectroscopy and transmission electron microscopy. It was indicated that these AgNPs have a remarkable amplifying effect on the terbium-sensitized fluorescence of fluoxetine. The effects of various parameters such as AgNP and Tb 3+ concentration and the pH of the media were investigated. Under obtained optimal conditions, the fluorescence intensity of the terbium-fluoxetine-AgNP system was enhanced linearly by increasing the concentration of fluoxetine in the range of 0.008 to 19 mg/L. The limit of detection (b + 3s) was 8.3 × 10 -4 mg/L. The interference effects of common species found in real samples were also studied. The method had good linearity, recovery, reproducibility and sensitivity, and was satisfactorily applied for the determination of fluoxetine in tablet formulations, human urine and plasma samples. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Determination of fluoroquinolone antibiotics by microchip capillary electrophoresis along with time-resolved sensitized luminescence of their terbium(III) complexes

International Nuclear Information System (INIS)

Sierra-Rodero, Marina; Fernández -Romero, Juan Manuel; Gómez -Hens, Agustina

2014-01-01

We report on the time-resolved detection of the three fluoroquinolone (FQs) antibiotics ciprofloxacin (CIP), enrofloxacin (ENR) and flumequine (FLU). On addition of terbium(III) ions, the terbium(III)-FQs chelates are formed in-situ in an on-capillary derivatization reaction of a microfluidic system. The laser-induced terbium(III)-sensitized luminescence of the chelates is measured at excitation/emission wavelengths of 337/545 nm. The analytes can be separated and quantified within less than 4 min. A solid phase extraction step for analyte preconcentration can be included prior to chelation and microchip capillary electrophoresis. The analytical ranges of the calibration graphs for CIP, ENR and FLU are from 10.6 to 60.0, 10.3 to 51.0, and 11.5 to 58.8 ng mL −1 , respectively, and the detection limits are 3.2, 3.1 and 3.6 ng mL −1 , respectively. The precision was established at two concentration levels of each analyte and revealed relative standard deviations in the range from 3.0 to 10.2 %. The method was applied to the analysis of FQ-spiked water samples. (author)

Cuticular hydrocarbons corroborate the distinction between lowland and highland Natal fruit fly (Tephritidae, Ceratitis rosa) populations

Czech Academy of Sciences Publication Activity Database

Vaníčková, Lucie; Břízová, Radka; Pompeiano, A.; Ekesi, S.; De Meyer, M.

-, č. 540 (2015), s. 507-524 ISSN 1313-2989 Institutional support: RVO:61388963 Keywords : Ceratitis rosa * cryptic species * chemotaxonomy * GCxGC/MS * integrative taxonomy Subject RIV: EG - Zoology Impact factor: 0.938, year: 2015 http://zookeys.pensoft.net/articles.php?id=6222

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

Enhanced sintering and conductivity study of cobalt or nickel doped solid solution of barium cerate and zirconate

DEFF Research Database (Denmark)

Ricote, Sandrine; Bonanos, Nikolaos

2010-01-01

BaZr(0.9 − x)CexY(0.1 − y)CoyO(3 − δ) (with x = 0 and 0.2; y = 0.01; 0.02; 0.05) and BaZr(0.9 − x)CexY(0.1 − y)NiyO(3 − δ) (with x = 0 and 0.2; y = 0.01; 0.02) compounds have been synthesized by solid state reaction at 1400 °C and obtained as dense pellets after sintering at 1450 °C. Cobalt...... or nickel doping reduces the sintering temperature by about 250 °C. The samples are stable in a CO2 rich atmosphere at 600 °C but the 5% B site Co doped samples are aging in wet atmosphere. The conductivity has been measured for the 1 and 2% doped samples (both cobalt and nickel), in different wet...

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.

{alpha}-particle induced reactions on yttrium and terbium

Energy Technology Data Exchange (ETDEWEB)

Mukherjee, S.; Kumar, B.B. [School of Studies in Physics, Vikram University, Ujjain-456010 (India); Rashid, M.H. [Variable Energy Cyclotron Center, 1/AF, Bidhan Nagar, Calcutta (India); Chintalapudi, S.N. [Inter-University Consortium for DAE Facilities, 3/LB, Bidhan Nagar, Calcutta (India)

1997-05-01

The stacked foil activation technique has been employed for the investigation of {alpha}-particle induced reactions on the target elements yttrium and terbium up to 50 MeV. Six excitation functions for the ({alpha},xn) type of reactions were studied using high-resolution HPGe {gamma}-ray spectroscopy. A comparison with Blann{close_quote}s geometric dependent hybrid model has been made using the initial exciton number n{sub 0}=4(4p0h) and n{sub 0}=5(5p0h). A broad general agreement is observed between the experimental results and theoretical predictions with an initial exciton number n{sub 0}=4(4p0h). {copyright} {ital 1997} {ital The American Physical Society}

α-particle induced reactions on yttrium and terbium

International Nuclear Information System (INIS)

Mukherjee, S.; Kumar, B.B.; Rashid, M.H.; Chintalapudi, S.N.

1997-01-01

The stacked foil activation technique has been employed for the investigation of α-particle induced reactions on the target elements yttrium and terbium up to 50 MeV. Six excitation functions for the (α,xn) type of reactions were studied using high-resolution HPGe γ-ray spectroscopy. A comparison with Blann close-quote s geometric dependent hybrid model has been made using the initial exciton number n 0 =4(4p0h) and n 0 =5(5p0h). A broad general agreement is observed between the experimental results and theoretical predictions with an initial exciton number n 0 =4(4p0h). copyright 1997 The American Physical Society

Cerium(terbium, erbium)chloride-choline chloride aqueous systems

International Nuclear Information System (INIS)

Gajfutdinova, R.K.; Zhuravlev, E.F.; Bikbaeva, G.G.; Domrachev, V.N.; Vanskova, G.I.

1985-01-01

To clarify the effect of rare earth nature on mutual solubility of rare earth salts and amines the solubility of solid phases in the systems, consisting of choline chloride, water and cerium, terbium, erbium chlorides, has been studied. It is established, that solubility isotherms of all the systems, testify to the formation of new solid phases of the composition: Ce(Tb, Er)xCl 3 x2C 5 H 14 ONClx3H 2 O. Individuality of new solid phases is proved by DTA method, the composition is confirmed by chemical analysis and data of PMR spectra, for choline chloride and its complexes with rare earth chlorides of the given composition PMR and IR spectra are studied

Rare-earth doped gadolinia based phosphors for potential multicolor and white light emitting deep UV LEDs.

Science.gov (United States)

Bedekar, Vinila; Dutta, Dimple P; Mohapatra, M; Godbole, S V; Ghildiyal, R; Tyagi, A K

2009-03-25

Gadolinium oxide host and europium/dysprosium/terbium doped gadolinium oxide nanoparticles were synthesized using the sonochemical technique. Gadolinium oxide nanocrystals were also co-doped with total 2 mol% of Eu(3+)/Dy(3+),Eu(3+)/Tb(3+),Dy(3+)/Tb(3+), and also Eu(3+)/Dy(3+)/Tb(3+) ions, by the same method. The nanoparticles obtained were characterized using powder x-ray diffraction (XRD), transmission electron microscopy (TEM), and selected area electron diffraction (SAED) techniques. The size of the particles ranged from 15 to 30 nm. The triple doped samples showed multicolor emission on single wavelength excitation. The photoluminescence results were correlated with the lifetime data to get an insight into the luminescence and energy transfer processes taking place in the system. On excitation at 247 nm, the novel nanocrystalline Gd(2)O(3):RE (RE = Dy, Tb) phosphor resulted in having very impressive CIE chromaticity coordinates of x = 0.315 and y = 0.316, and a correlated color temperature of 6508 K, which is very close to standard daylight.

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.

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

Pos-harvest control of Ceratitis capitata (Wiedemann, 1824) (Diptera: Tephritidae) in guava fruits (Psidium guajava L.)

International Nuclear Information System (INIS)

Doria, Hayda Oliveira Souza

2006-01-01

The objective of this work is to evaluate the effect of the treatment with steam heating, hot water and gamma radiation of Co-60 on eggs and fruit flies larvae (Ceratitis capitata Wiedemann, 1824) (Diptera: Tephritidae), and analyze the effect of these treatments in the fruit quality (chemical composition)

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)

A hydrometallurgical process for the recovery of terbium from fluorescent lamps: Experimental design, optimization of acid leaching process and process analysis.

Science.gov (United States)

Innocenzi, Valentina; Ippolito, Nicolò Maria; De Michelis, Ida; Medici, Franco; Vegliò, Francesco

2016-12-15

Terbium and rare earths recovery from fluorescent powders of exhausted lamps by acid leaching with hydrochloric acid was the objective of this study. In order to investigate the factors affecting leaching a series of experiments was performed in according to a full factorial plan with four variables and two levels (4 2 ). The factors studied were temperature, concentration of acid, pulp density and leaching time. Experimental conditions of terbium dissolution were optimized by statistical analysis. The results showed that temperature and pulp density were significant with a positive and negative effect, respectively. The empirical mathematical model deducted by experimental data demonstrated that terbium content was completely dissolved under the following conditions: 90 °C, 2 M hydrochloric acid and 5% of pulp density; while when the pulp density was 15% an extraction of 83% could be obtained at 90 °C and 5 M hydrochloric acid. Finally a flow sheet for the recovery of rare earth elements was proposed. The process was tested and simulated by commercial software for the chemical processes. The mass balance of the process was calculated: from 1 ton of initial powder it was possible to obtain around 160 kg of a concentrate of rare earths having a purity of 99%. The main rare earths elements in the final product was yttrium oxide (86.43%) following by cerium oxide (4.11%), lanthanum oxide (3.18%), europium oxide (3.08%) and terbium oxide (2.20%). The estimated total recovery of the rare earths elements was around 70% for yttrium and europium and 80% for the other rare earths. Copyright © 2016 Elsevier Ltd. All rights reserved.

Resolution of three cryptic agricultural pests (Ceratitis fasciventris, C. anonae, C. rosa, Diptera: Tephritidae) using cuticular hydrocarbon profiling

Czech Academy of Sciences Publication Activity Database

Vaníčková, Lucie; Virgilio, M.; Tomčala, Aleš; Břízová, Radka; Ekesi, S.; Hoskovec, Michal; Kalinová, Blanka; do Nascimento, R. R.; De Meyer, M.

2014-01-01

Roč. 104, č. 5 (2014), s. 631-638 ISSN 0007-4853 Institutional support: RVO:61388963 Keywords : cryptic species complex * genus Ceratitis * cuticular hydrocarbons * polymorphic microsatellite loci * chemotaxonomy Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.910, year: 2014

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

Determination of trace amounts of rare earth elements in samarium, terbium and disprosium oxides by graphite furnace atomic-absorption spectrometry

International Nuclear Information System (INIS)

Dantas, E.S.K.

1990-01-01

A graphite furnace atomic-absorption spectrometry method for the determination of neodymium, europium, terbium, dysprosium and yttrium at trace level in samarium oxide; of samarium, europium, dysprosium, holmium, erbium and yttrium in terbium oxide and of europium, terbium, holmium, erbium and yttrium in dysprosium oxide was established. The best pyrolysis and atomization temperatures were determined for each lanthanide considered. Calibration curves were obtained for the pure elements, for binary mixtures formed by the matrix and each of the lanthanides studied and, finally, for the complex mixtures constituted by the matrix and all the other lanthanide of the group under scrutiny. This study has been carried out to examine the interference of the presence of one lanthanide on the behaviour of the other, since a lack of linearity on the calibration curves has been observed in some cases. Detection and determination limits have been determined as well. The detection limits encountered were within the range 0.002 to 0.3% for different elements. The precision of the method expressed as the relative standard deviation was calculated for each element present in each of the matrices studied. The conclusion arrived at is that the method can be applied for determining the above mentioned lanthanides present in the matrices studied with purity up to 99.50%. (author)

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

Medhost: An encyclopedic bibliography of the host plants of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), version 3.0

Science.gov (United States)

The Mediterranean fruit fly (Medfly), Ceratitis capitata (Wiedemann), causes direct damage to fruits and vegetables through oviposition and larval feeding. Rigorous quarantine procedures are currently enforced to prevent domestic and transnational spread of Medfly. Accessible and reliable informatio...

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

Short range attraction of Ceratitis capitata (Diptera: Tephritidae) sterile males to six commercially available plant essential oils

Science.gov (United States)

Plant essential oils have a number of roles in insect pest management. For male Ceratitis capitata, this includes use of angelica seed oil as long range attractants and ginger root oil as aromatherapy, which is exposure to sterile males to increase mating success. Neither of these plants are hosts f...

comparative studies on pyriproxyfen and fenoxycarb as juvenile hormones applied separately or combined with gamma radiation for controlling the mediterranean fruit fly, ceratitis capitata (Wied)

International Nuclear Information System (INIS)

Fadel, A.M.; Othman, K.S.A.

1998-01-01

Comparative studies on pyriproxyfen and fenoxycarb as juvenile hormones applied separately or combined with gamma radiation were carried out for controlling ceratitis capitata. Lc 50's of the two juvenile hormones, pyriproxfen and fenoxycarb, were determined against ceratitis capitata in treated diet by continuous contact of eggs and larvae using various concentrations. The Lc 50 were 32 and 140 ppm for pyriproxyfen and fenoxycarb, respectively. The resulting pupae were gamma irradiated with 90 Gy. Larval and pupal durations were insignificantly affected, pupation and adult emergence were significantly affected while adult survival was insignificantly affected when applying the two JH's. Applying pyriproxyfen alone insignificantly increased egg hatch at the concentrations used (12.5 and 25 ppm) while when fenoxycarb was applied alone egg hatch was significantly decreased at the concentration used (100 ppm). Applying both juvenile hormones each combined with gamma radiation significantly reduced egg hatch. Male mating competitiveness was significantly increased when applying pyriproxyfen at the concentration 25 Ppm. Results indicated that pyriproxyfen was more effective than fenoxycarb against the mediterranean fruit fly ceratitis capitata.1 figs., 3 tabs

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.

Biology studies and improvement of Ceratitis capitata (Wiedemann) mass trapping control technique

OpenAIRE

Peñarrubia María, Esther

2010-01-01

Ceratitis capitata (Wiedemann) (mosca de la fruita), està considerada a nivell mundial com una de les plagues més destructives de fruits degut a la seva elevada capacitat de causar danys en la producció, la seva distribució global i al seu ampli rang d‟hostes. S‟ha desenvolupat un model eficaç de control integrat de plagues (IPM), que ha estat acceptat a Europa com estratègia de protecció vegetal per a una agricultura sostenible. L‟objectiu del present treball va ser l‟...

Isolation of strains of Bacillus thuringiensis insecticidal biological activity against Ceratitis capitata

International Nuclear Information System (INIS)

Hmaied, Ezzedine; Ben Mbarek, Wael

2010-01-01

The present work is to study the effect of toxins (δ-endotoxins) extracted from strains of Bacillus thuringiensis isolated from the mud on the fly Sabkhat Dejoumi Ceratitis capitata, a pest of citrus and fruit trees. Among 51 isolated tested, 15 showed a very significant insecticidal activity, characterized by mortality rates exceeding 80 pour cent. These mortality rates are caused by endotoxins of Bt revealed variability between them. The preliminary results of this study encourage us towards the characterization of the insecticidal activity produced by strains of Bt for large scale application.

Instar- and host-associated differentiation of bacterial communities in the Mediterranean fruit fly Ceratitis capitata

OpenAIRE

Malacrinò, Antonino; Campolo, Orlando; Medina, Raul F; Palmeri, Vincenzo

2018-01-01

Microorganisms are acknowledged for their role in shaping insects' evolution, life history and ecology. Previous studies have shown that microbial communities harbored within insects vary through ontogenetic development and among insects feeding on different host-plant species. In this study, we characterized the bacterial microbiota of the highly polyphagous Mediterranean fruit fly, Ceratitis capitata (Diptera: Tephritidae), at different instars and when feeding on different host-plant speci...

Acceptance and preference of fruits for oviposition in two Ceratitis capitata (Diptera, Tephritidae) populations

OpenAIRE

Joachim-Bravo, Iara Sordi; Silva-Neto, Alberto Moreira da

2004-01-01

The influence of four host fruits, orange (Citrus sinensis L.), papaya (Carica papaya L.), mango (Mangifera indica L.) and apple (Malus domestica Borkh) on oviposition behavior of Ceratitis capitata (Wiedemann, 1824) was evaluated. Experiments were carried out on two C. capitata laboratory-reared populations: one with artificial diet for 10 years with periodic introduction of wild flies and other reared with artificial diet for 20 years without wild flies introduction. In acceptance experimen...

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

Synthesis and luminescence properties of europium and terbium complexes with pyridine- or bipyridine-linked oligothiophene ligand

International Nuclear Information System (INIS)

Liu Ping; Huang Mingsheng; Pan Wanzhang; Zhang Yamin; Hu Jianhua; Deng Wenji

2006-01-01

With an aim to develop novel luminescence materials, europium and terbium complexes of 2,5-(2-thiophene)-pyridine (TPY) and 5,5'-bis(5-(2,2'-bithiophene))-2,2'-bipyridine (B2TBPY) were synthesized, and their luminescence properties studied. The complexes exhibit ligand-sensitized emission, which is typical of Eu(III) and Tb(III) ions

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.

Preparation and photoluminescence characteristics of In(OH){sub 3}:xTb{sup 3+} obtained by Microwave-Assisted Hydrothermal method

Energy Technology Data Exchange (ETDEWEB)

Motta, F.V., E-mail: fabiana@ct.ufrn.br [DEMAT, CT, UFRN, Av. Sen. Salgado Filho 3000, CEP 59072-970 Natal, RN (Brazil); Marques, A.P.A. [UNIFESP, Rua Prof. Artur Riedel 275, CEP 09972-270 Diadema, SP (Brazil); Li, M.S. [IFSC, USP, Av. Trabalhador São Carlense 400, CEP 13566-590 São Carlos, SP (Brazil); Abreu, M.F.C. [LIEC, DQ, UFSCar, Via Washington Luiz, km 235, CEP 13565-905 São Carlos, SP (Brazil); Paskocimas, C.A.; Bomio, M.R.D. [DEMAT, CT, UFRN, Av. Sen. Salgado Filho 3000, CEP 59072-970 Natal, RN (Brazil); Souza, R.P. [DEP, CT, UFRN, Av. Sen. Salgado Filho 3000, CEP 59072-970 Natal, RN (Brazil); Varela, J.A. [LIEC, IQ, UNESP, Rua Francisco Degni s/n, CEP 14801-907 Araraquara, SP (Brazil); Longo, E. [LIEC, DQ, UFSCar, Via Washington Luiz, km 235, CEP 13565-905 São Carlos, SP (Brazil)

2013-03-15

Highlights: ► We report the preparation by Microwave-Hydrothermal method of In(OH){sub 3}:xTb{sup 3+}. ► Nanostructures were obtained at a low temperature. ► The crystallite size decreased with terbium doping level. ► The nucleation–dissolution–recrystallization mechanism is promoted by processing. ► This material is a highly promising candidate for photoluminescent applications. -- Abstract: Crystalline terbium-doped indium hydroxide structures were prepared by a rapid and efficient Microwave-Assisted Hydrothermal (MAH) method. Nanostructures were obtained at a low temperature. FE-SEM images confirm that these samples are composed of 3D nanostructures. XRD, optical diffuse reflectance and photoluminescence (PL) measurements were used to characterize the products. Emission spectra of terbium-doped indium hydroxide (In(OH){sub 3}:xTb{sup 3+}) samples under excitation (350.7 nm) presented broad band emission referent to the indium hydroxide matrix and {sup 5}D{sub 4} → {sup 7}F{sub 6}, {sup 5}D{sub 4} → {sup 7}F{sub 5}, {sup 5}D{sub 4} → {sup 7}F{sub 4}, and {sup 5}D{sub 4} → {sup 7}F{sub 3} terbium transitions at 495, 550, 590 and 627 nm, respectively. Relative intensities of the Tb{sup 3+} emissions increased as the concentration of this ion increased from 0, 1, 2, 4 and 8 mol%, of Tb{sup 3+}, but the luminescence is drastically quenched for the In(OH){sub 3} matrix.

Oviposition preference hierarchy in Ceratitis capitata (Diptera, Tephritidae): influence of female age and experience

OpenAIRE

Joachim-Bravo, Iara S.; Fernandes, Odair A.; Bortoli, Sérgio A.; Zucoloto, Fernando S.

2001-01-01

The influence of two factors, age and previous experience, on the oviposition hierarchy preference of Ceratitis capitata (Wiedemann, 1824) females was studied. Two populations were analyzed: one reared in laboratory during 17 years and the other captured in nature. In the first experiment the oviposition preference for four fruits, papaya, orange, banana and apple was tested at the beginning of oviposition period and 20 days past. The results showed that the wild females as much the laborator...

Field estimates of attraction of Ceratitis capitata to Trimedlure and Bactrocera dorsalis (Diptera: Tephritidae) to methyl eugenol in varying environments

Science.gov (United States)

Measuring and modeling the attractiveness of semiochemical-baited traps is of significant importance to detection, delimitation and control of invasive pests. Here we describe the results of field mark-release-recapture experiments with Ceratitis capitata (Wiedemann) and Bactrocera dorsalis (Hendel)...

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.

Development of the formal genetics of the Mediterranean fruitfly, Ceratitis capitata Wied

International Nuclear Information System (INIS)

Roessler, Y.

1980-07-01

An attempt was made to develop Medfly (Ceratitis capitata) strains with a sex-limited dimorphism permitting automated sex-sorting through pupal colour dimorphism. (Such sorting is important in sterile insect release). This can be achieved by ''translocating'' mutant pupal colour alleles into the male's Y-chromosome. The Y-chromosome translocations were effected by irradiating wild-type males with 1.0-1.2 Krad of gamma radiation, followed by appropriate crossing. The results have been published in Entomophaga 24(1979)411-416). The effect of sterilization on fertility and competitiveness of males of the ''69-apricot'' line was investigated

Quality measurements of the gamma irradiated medfly ceratitis capitata wied

International Nuclear Information System (INIS)

Elkholy, E.M.S.

1986-01-01

The damage caused by the mediterranean fruit fly (Medfly) Ceratitis capitata (Wiedemann) to Egyptian agriculture is increasing mainly because farmers are finding it harder to choose suitable means of control in view of the difficulties frequently associated with the use of insecticides, such as undesirable residues and biological disequilibrium. Recently, the sterile-insect technique has opened up new possibilities of this insect control in egypt. The use of sterile insects to eradicate or suppress populations of pests was conceived by knipling,(1955) and applied successfully for the first time in 1954 against the screw-worm fly, cochliomyia hominivorax (cocquerel) on the island of curacao (Baumhover et al., 1955) and then in 1958 and 1959 in the south-eastern united states of america (knipling, 1960)

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....

Detection of resistance to the organophosphate insecticide in wild populations of medfly Ceratitis capitata

International Nuclear Information System (INIS)

Mimouni, Wafa

2011-01-01

In this study, the wild medfly resistance of the organophosphate insecticide is evaluated by the physiologic mechanism of resistance including the Acethylcholinesterase enzyme. Different representative populations of Ceratitis were collected from different regions of Tunisia. The analysis statistics (ACP) for DL50 and the treatment frequency showed a negative correlation between them. The gene ace was amplified at the level of the exons 4, 5, 6 et 7 by PCR. No mutation of the gene ace was identified with the collected individuals.

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

Structural Characterization and Absolute Luminescence Efficiency Evaluation of Gd2O2S High Packing Density Ceramic Screens Doped with Tb3+ and Eu3+ for further Applications in Radiology

Science.gov (United States)

Dezi, Anna; Monachesi, Elenasophie; D'Ignazio, Michela; Scalise, Lorenzo; Montalto, Luigi; Paone, Nicola; Rinaldi, Daniele; Mengucci, Paolo; Loudos, George; Bakas, Athanasios; Michail, Christos; Valais, Ioannis; Fountzoula, Christine; Fountos, George; David, Stratos

2017-11-01

Rare earth activators are impurities added in the phosphor material to enhance probability of visible photon emission during the luminescence process. The main activators employed are rare earth trivalent ions such as Ce+3, Tb+3, Pr3+ and Eu+3. In this work, four terbium-activated Gd2O2S (GOS) powder screens with different thicknesses (1049 mg/cm2, 425.41 mg/cm2, 313 mg/cm2 and 187.36 mg/cm2) and one europium-activated GOS powder screen (232.18 mg/cm2) were studied to investigate possible applications for general radiology detectors. Results presented relevant differences in crystallinity between the GOS:Tb doped screens and GOS:Eu screens in respect to the dopant agent present. The AE (Absolute efficiency) was found to rise (i) with the increase of the X-ray tube voltage with the highest peaking at 110kVp and (ii) with the decrease of the thickness among the four GOS:Tb. Comparing similar thickness values, the europium-activated powder screen showed lower AE than the corresponding terbium-activated.

Preparation and photoluminescence enhancement in terbium(III ternary complexes with β-diketone and monodentate auxiliary ligands

Directory of Open Access Journals (Sweden)

Devender Singh

2016-12-01

Full Text Available A series of new solid ternary complexes of terbium(III ion based on β-diketone ligand acetylacetone (acac and monodentate auxiliary ligands (aqua/urea/triphenylphosphineoxide/pyridine-N-oxide had been prepared. The structural characterizations of synthesized ternary compounds were studied by means of elemental analysis, infrared (IR, and proton nuclear magnetic resonance (NMR spectral techniques. The optical characteristics were investigated with absorption as well as photoluminescence spectroscopy. Thermal behavior of compounds was examined by TGA/DTA analysis and all metal complexes were found to have good thermal stability. The luminescence decay time of complexes were also calculated by monitoring at emission wavelength corresponding to 5D4 → 7F5 transition. A comparative inspection of the luminescent behavior of prepared ternary compounds was performed in order to determine the function of auxiliary ligands in the enhancement of luminescence intensity produced by central terbium(III ion. The color coordinates values suggested that compounds showed bright green emission in visible region in electromagnetic spectrum. Complexes producing green light could play a significant role in the fabrication of efficient light conversion molecular devices for display purposes and lightning systems.

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.)

Synthesis and characterization of magnetic nanoparticles of oxides for dual MnFe2O4 bioseparation, stabilized in fatty acid and the system chitosan - Eu(TTA)3(TPPO)2. Studies on the influence of doping with Gd3+, Tb3+, Ho3+ e Eu3+ in structural and magnetic properties

International Nuclear Information System (INIS)

Kovacs, Thelma Antunes Rodrigues

2014-01-01

This work was synthesized and characterized ferrite magnetic nanoparticles manganese, using the chemical coprecipitation method. By varying the heating time under 98°C (0, 10,20,40,60 3 80 minutes), the molar percentage of doping (1, 3, 5, 7, and 10%), gadolinium, europium, terbium and holmium. Magnetic ferrite nanoparticles and manganese ferrite doped with manganese were synthesized by coprecipitation method starting with chloride solutions of metals (iron (III), manganese (II), europium (III), gadolinium (III), terbium (III) and holmium (III)) and NaOH 5mol.L -1 as precipitating agent. The magnetic nanoparticles were characterized by scanning electron microscopy, infrared spectroscopy, X-ray diffraction, magnetization curves, and thermal analysis. Most of manganese ferrite particles showed superparamagnetic behavior. After the characterization it was found that the samples synthesized manganese ferrite with more than 40 minutes heating time, crystal structure showed the characteristic pattern of the inverted manganese ferrite spinel type. The stabilization of the samples in oleic acid nanoparticles produced with a hydrophobic outer layer and facilitated by coating chitosan biopolymer, since this has a positive charge. Among the doped samples there was no significant change in the magnetic behavior. Several techniques for characterizing these materials have been used such as X-ray diffraction spectrum in the infrared region, magnetization curves and thermal analysis. The resins were tested as magnetic material for the separation of biological materials. In this paper, are used as biological targets separation of bovine serum albumin. (author)

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.

Cerium fluoride nanoparticles protect cells against oxidative stress

International Nuclear Information System (INIS)

Shcherbakov, Alexander B.; Zholobak, Nadezhda M.; Baranchikov, Alexander E.; Ryabova, Anastasia V.; Ivanov, Vladimir K.

2015-01-01

A novel facile method of non-doped and fluorescent terbium-doped cerium fluoride stable aqueous sols synthesis is proposed. Intense green luminescence of CeF 3 :Tb nanoparticles can be used to visualize these nanoparticles' accumulation in cells using confocal laser scanning microscopy. Cerium fluoride nanoparticles are shown for the first time to protect both organic molecules and living cells from the oxidative action of hydrogen peroxide. Both non-doped and terbium-doped CeF 3 nanoparticles are shown to provide noteworthy protection to cells against the vesicular stomatitis virus. - Highlights: • Facile method of CeF 3 and CeF 3 :Tb stable aqueous sols synthesis is proposed. • Naked CeF 3 nanoparticles are shown to be non-toxic and to protect cells from the action of H 2 O 2 . • CeF 3 and CeF 3 :Tb nanoparticles are shown to protect living cells against the vesicular stomatitis virus

Cerium fluoride nanoparticles protect cells against oxidative stress

Energy Technology Data Exchange (ETDEWEB)

Shcherbakov, Alexander B.; Zholobak, Nadezhda M. [Zabolotny Institute of Microbiology and Virology, National Academy of Sciences of Ukraine, Kyiv D0368 (Ukraine); Baranchikov, Alexander E. [Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Moscow 119991 (Russian Federation); Ryabova, Anastasia V. [Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow 119991 (Russian Federation); National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow 115409 (Russian Federation); Ivanov, Vladimir K., E-mail: van@igic.ras.ru [Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Moscow 119991 (Russian Federation); National Research Tomsk State University, Tomsk 634050 (Russian Federation)

2015-05-01

A novel facile method of non-doped and fluorescent terbium-doped cerium fluoride stable aqueous sols synthesis is proposed. Intense green luminescence of CeF{sub 3}:Tb nanoparticles can be used to visualize these nanoparticles' accumulation in cells using confocal laser scanning microscopy. Cerium fluoride nanoparticles are shown for the first time to protect both organic molecules and living cells from the oxidative action of hydrogen peroxide. Both non-doped and terbium-doped CeF{sub 3} nanoparticles are shown to provide noteworthy protection to cells against the vesicular stomatitis virus. - Highlights: • Facile method of CeF{sub 3} and CeF{sub 3}:Tb stable aqueous sols synthesis is proposed. • Naked CeF{sub 3} nanoparticles are shown to be non-toxic and to protect cells from the action of H{sub 2}O{sub 2}. • CeF{sub 3} and CeF{sub 3}:Tb nanoparticles are shown to protect living cells against the vesicular stomatitis virus.

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.

Autofluorescence-Free Live-Cell Imaging Using Terbium Nanoparticles.

Science.gov (United States)

Cardoso Dos Santos, M; Goetz, J; Bartenlian, H; Wong, K-L; Charbonnière, L J; Hildebrandt, N

2018-04-18

Fluorescent nanoparticles (NPs) have become irreplaceable tools for advanced cellular and subcellular imaging. While very bright NPs require excitation with UV or visible light, which can create strong autofluorescence of biological components, NIR-excitable NPs without autofluorescence issues exhibit much lower brightness. Here, we show the application of a new type of surface-photosensitized terbium NPs (Tb-NPs) for autofluorescence-free intracellular imaging in live HeLa cells. The combination of exceptionally high brightness, high photostability, and long photoluminecence (PL) lifetimes for highly efficient suppression of the short-lived autofluorescence allowed for time-gated PL imaging of intracellular vesicles over 72 h without toxicity and at extremely low Tb-NP concentrations down to 12 pM. Detection of highly resolved long-lifetime (ms) PL decay curves from small (∼10 μm 2 ) areas within single cells within a few seconds emphasized the unprecedented photophysical properties of Tb-NPs for live-cell imaging that extend well beyond currently available nanometric imaging agents.

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)

Investigation of the luminescent properties of terbium-anthranilate complexes and application to the determination of anthranilic acid derivatives in aqueous solutions

Energy Technology Data Exchange (ETDEWEB)

Arnaud, N.; Georges, J

2003-01-10

The luminescent properties of terbium complexes with furosemide (FR), flufenamic (FF) acid, tolfenamic (TF) acid and mefenamic (MF) acid have been investigated in aqueous solutions. For all four compounds, complexation occurs when the carboxylic acid of the aminobenzoic group is dissociated and is greatly favoured in the presence of trioctylphosphine oxide as co-ligand and Triton X-100 as surfactant. Under optimum conditions, luminescence of the lanthanide ion is efficiently sensitised and the lifetime of the {sup 5}D{sub 4} resonance level of terbium in the complex is ranging between 1 and 1.9 ms, against 0.4 ms for the aqua ion. The sensitivity of the method for the determination of anthranilic acid derivatives is improved by one to two orders of magnitude with respect to that achieved using native fluorescence or terbium-sensitised luminescence in methanol. The limits of detection are 2x10{sup -10}, 5x10{sup -10} and 2x10{sup -9} mol l{sup -1} for flufenamic acid, furosemide and tolfenamic acid, and mefenamic acid, respectively, with within-run RSD values of less than 1%. The method has been applied to the determination of flufenamic acid in spiked calf sera with and without sample pretreatment. Depending on the method and the analyte concentration, the recovery was ranging between 83 and 113% and the lowest concentration attainable in serum samples was close to 1x10{sup -7} mol l{sup -1}.

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)

The Process of Intromission in the Mediterranean Fruit Fly, Ceratitis capitata (Diptera: Tephritidiae

Directory of Open Access Journals (Sweden)

William G. Eberhard

1995-01-01

Full Text Available The distiphallus of the male of Ceratitis capitata is folded back 180° onto the basiphallus during the early stages of intromission, and is then unfolded within the female. Repeated folding and unfolding may occur within the female. Two membranous sacs on the distiphallus are capable of rhythmic cycles of inflation and deflation. Inflations of the sac near the base of the distiphallus probably help propel the aedeagus deeper into the female, along with periodic stiffening of the basiphallus; inflation of the larger, distal sac may drive the genital rod (which does not transfer sperm into the ventral receptacle.

Seasonal occurrence of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann, 1824) (Diptera: Tephritidae) in southern Syria

OpenAIRE

Mansour Mohammed; Mohamad Fater

2016-01-01

Population fluctuations of the Mediterranean fruit fly (medfly), Ceratitis capitata, were investigated between 1999 and 2001 at several locations representing fruit production areas in the southern part of Syria (Damascus Ghota, Zabadani, Sargaiah, Rankus, Orneh and Ain Al-Arab). Medfly adults were monitored weekly all year around using Jackson traps baited with trimedlure dispensers. Larvae were also sampled in Damascus Ghota by collecting fruits from ripe or ripening fruit trees and recordi...

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.

Resonance energy transfer from quinolinone modified polystyrene-block-poly(styrene-alt-maleic anhydride) copolymer to terbium(III) metal ions

Czech Academy of Sciences Publication Activity Database

Výprachtický, Drahomír; Mikeš, F.; Lokaj, Jan; Pokorná, Veronika; Cimrová, Věra

2015-01-01

Roč. 160, April (2015), s. 27-34 ISSN 0022-2313 R&D Projects: GA ČR GAP106/12/0827; GA ČR(CZ) GA13-26542S Institutional support: RVO:61389013 Keywords : energy transfer * terbium luminescence * quinolinone donor Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.693, year: 2015

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.

Effect of successive irradiated generations on the biological activities of the mediterranean fruit fly, ceratitis capitata (Wled)

International Nuclear Information System (INIS)

Shoukry, M.A.; Guneidy, A.M.; Wakid, A.D.; El-Kholy, M.S.

1995-01-01

The accumulated effects of irradiated materials in the mediterranean fruit fly (medfly), ceratitis capitata (Wied) offsprings resulted from successively irradiated generations of eggs, pupae or adults were evaluated . Results showed that successive irradiation affected only the biological parameters that concern with the genetic cells i.e. sterility and fecundity. On the other hand, parameters concern the somatic cells i.e. Survival, sex-ration and mating activity were not significantly affected

Detection of Bacterial Endospores in Soil by Terbium Fluorescence

Directory of Open Access Journals (Sweden)

Andrea Brandes Ammann

2011-01-01

Full Text Available Spore formation is a survival mechanism of microorganisms when facing unfavorable environmental conditions resulting in “dormant” states. We investigated the occurrence of bacterial endospores in soils from various locations including grasslands (pasture, meadow, allotment gardens, and forests, as well as fluvial sediments. Bacterial spores are characterized by their high content of dipicolinic acid (DPA. In the presence of terbium, DPA forms a complex showing a distinctive photoluminescence spectrum. DPA was released from soil by microwaving or autoclaving. The addition of aluminium chloride reduced signal quenching by interfering compounds such as phosphate. The highest spore content (up to 109 spores per gram of dry soil was found in grassland soils. Spore content is related to soil type, to soil depth, and to soil carbon-to-nitrogen ratio. Our study might provide a basis for the detection of “hot spots” of bacterial spores in soil.

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

Magnetoresistance in terbium and holmium single crystals

International Nuclear Information System (INIS)

Singh, R.L.; Jericho, M.H.; Geldart, D.J.W.

1976-01-01

The longitudinal magnetoresistance of single crystals of terbium and holmium metals in their low-temperature ferromagnetic phase has been investigated in magnetic fields up to 80 kOe. Typical magnetoresistance isotherms exhibit a minimum which increases in depth and moves to higher fields as the temperature increases. The magnetoresistance around 1 0 K, where inelastic scattering is negligible, has been interpreted as the sum of a negative contribution due to changes in the domain structure and a positive contribution due to normal magnetoresistance. At higher temperatures, a phenomenological approach has been developed to extract the inelastic phonon and spin-wave components from the total measured magnetoresistance. In the temperature range 4--20 0 K (approximately), the phonon resistivity varies as T 3 . 7 for all samples. Approximate upper and lower bounds have been placed on the spin-wave resistivity which is also found to be described by a simple power law in this temperature range. The implications of this result for theoretical treatments of spin-wave resistivity due to s-f exchange interactions are considered. It is concluded that the role played by the magnon energy gap is far less transparent than previously suggested

Progress and problems in the cytology of Ceratitis capitata

International Nuclear Information System (INIS)

Bedo, D.G.

1989-01-01

In recent years of cytological work with Ceratitis capitata has expanded rapidly in concert with increased interest in the application of genetics and molecular biology in the control of this species. Previous studies using mitotic chromosomes produced essential basic karyotypic data but resulted in a confused situation in which several chromosome nomenclature systems were in use. The need for better cytological methods and a standardization of nomenclature was recognised by the IAEA which recommended a system based on that used for Drosophila melanogaster. Polytene chromosome analysis was soon available with the development of techniques for preparing chromosome squashes from male pupal orbital trichogen cells and larval salivary glands. The application of chromosome banding techniques quickly provided detailed morphological information on mitotic chromosomes, particularly the sex chromosomes, and mapping of chromosome rearrangement break-points on newly prepared polytene chromosome maps commenced. This report describes recent unpublished results and offers comments on the still unresolved nomenclature problems in C. capitata

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.

Barium-137 M milkers based on 12-molybdo cerate column matrix. Vol. 3

Energy Technology Data Exchange (ETDEWEB)

El-absy, M A; El-Enien, M A; El-Said, H; Raieh, M [Isotopes and Rdioisotope Generators Department, Hot Laboratories Center, Atomic Energy Authority, Cairo (Egypt)

1996-03-01

The interaction of {sup 134} Cs{sup +} and {sup 131},{sup 133} Ba{sup 2+} radiotracers (10{sup -4} M for each) in HCl, H N O{sub 3}, Na Cl, Na N O{sub 3}, and N H{sub 4} Cl solutions on 12-Molybdo cerate (IV) has been studied by batch equilibrium at room temperature. The corresponding distribution coefficients (K{sub d} values in mi/g) were determined as a function of the composition of the reaction medium and drying temperature; 50, 150 and 200 degree C of the molybdate matrix under comparable conditions, Cs{sup +} ions are strongly retained on the adsorbent material than Ba{sup 2+} ions. Elution performance of the daughter {sup 134m} Ba (T{sub 1/}2=2.7 min.) from its parent {sup 137} Cs (T{sub 1/2}=30 y) was investigated on small chromatographic columns of the matrix. Based on the data obtained, 2 g 12-molybdo cerate (IV), dried at 200 degree C, loaded with 1 mCi {sup 137} Cs/{sup 137m} Ba milkers was prepared. The generated {sup 137m} Ba daughter was continuously eluted by passing a mixture solution of 0.1 M HCl + 0.1 M N H{sub 4} Cl as eluent through the column bed at flow rates of 1 and 2 m1/min. Eluate assessment proved reproducibility of the elution yields about 58% {sup 137m} Ba in 5 m1 eluate. Radionuclidic and chemical purity of the eluate proved to be suitable for use in nuclear medicine and also industrial applications. 6 figs., 1 tab.

Defect induced photoluminescence in MoS2 quantum dots and effect of Eu3+/Tb3+ co-doping towards efficient white light emission

Science.gov (United States)

Haldar, Dhrubaa; Ghosh, Arnab; Bose, Saptasree; Mondal, Supriya; Ghorai, Uttam Kumar; Saha, Shyamal K.

2018-05-01

Intensive research has been carried out on optical properties of MoS2 quantum dots for versatile applications in photo catalytic, sensing and optoelectronic devices. However, white light generation from MoS2 quantum dots particularly using doping effect is relatively unexplored. Herein we report successful synthesis of Europium (Eu)/Terbium (Tb) co-doped MoS2 quantum dots to achieve white light for potential applications in optoelectronic devices. The dopant ions are introduced into the host lattice to retain the emission colors to cover the entire range of visible light of solar spectrum. Perfect white light (CIE = 0.31, 0.33) with high intensity (quantum yield = 28.29%) is achieved in these rare earth elements co-doped quantum dot system. A new peak is observed in the NIR region which is attributed to the defects present in MoS2 quantum dots. Temperature dependent study has been carried out to understand the origin of this new peak in the NIR region. It is seen that the 'S' defects in the QDs cause the appearance of this peak which shows a blue shift at higher temperature.

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...

Sensitivity of Ceratitis capitata eggs irradiated in artificial diet and in mango fruits

International Nuclear Information System (INIS)

Raga, A.; Yasuoka, S.T.; Amorim, E.O.; Sato, M.E.; Suplicy Filho, N.; Faria, J.T. de

1996-01-01

The objective of this study was to establish gamma radiation doses required to prevent emergence of Ceratitis capitata adults, from irradiated eggs in artificial diet and mango fruits. Six-, twelve-, twenty-four-, and forty-eight-hour-old eggs were used. Artificial infestation by C. capitata was carried out in mangoes of Haden, Tommy and Keith cultivars. An increase of radiation resistance of C. capitata eggs was observed as a function of the embryonic development and a Probit 9 of 24.67 Gy was estimated for 48-hour-old eggs in artificial diet. No significant influence of mango fruits was found on the efficacy of irradiation. (author)

Structure and luminescence spectra of lutetium and yttrium borates synthesized from ammonium nitrate melt

International Nuclear Information System (INIS)

Klassen, Nikolay V.; Shmurak, Semion Z.; Shmyt'ko, Ivan M.; Strukova, Galina K.; Derenzo, Stephen E.; Weber, Marvin J.

2005-01-01

Lutetium and yttrium borates doped with europium, terbium, gadolinium, etc. have been synthesized by dissolving initial oxides and nitrates in ammonium nitrate melt and thermal decomposition of the solvent. Annealings in the range of 500-1100 deg. C modified the dimensions of the grains from 2 to 3 nm to more than 100 nm. Significant dependence of the structure of lutetium borate on slight doping with rare earth ions has been found: terbium makes high-temperature vaterite phase preferential at room temperature, whereas europium stabilizes low-temperature calcite phase. Influence of the structure of the borates on the pattern of the luminescence spectra of europium dopant was observed. Possibilities for manufacturing of scintillating lutetium borate ceramics by means of this method of synthesis are discussed

Structure and luminescence spectra of lutetium and yttrium borates synthesized from ammonium nitrate melt

Science.gov (United States)

Klassen, Nikolay V.; Shmurak, Semion Z.; Shmyt'ko, Ivan M.; Strukova, Galina K.; Derenzo, Stephen E.; Weber, Marvin J.

2005-01-01

Lutetium and yttrium borates doped with europium, terbium, gadolinium, etc. have been synthesized by dissolving initial oxides and nitrates in ammonium nitrate melt and thermal decomposition of the solvent. Annealings in the range of 500-1100°C modified the dimensions of the grains from 2 to 3 nm to more than 100 nm. Significant dependence of the structure of lutetium borate on slight doping with rare earth ions has been found: terbium makes high-temperature vaterite phase preferential at room temperature, whereas europium stabilizes low-temperature calcite phase. Influence of the structure of the borates on the pattern of the luminescence spectra of europium dopant was observed. Possibilities for manufacturing of scintillating lutetium borate ceramics by means of this method of synthesis are discussed.

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.

Further optimization of barium cerate properties via co-doping strategy for potential application as proton-conducting solid oxide fuel cell electrolyte

Science.gov (United States)

Wang, Shuai; Shen, Jianxing; Zhu, Zhiwen; Wang, Zhihao; Cao, Yanxin; Guan, Xiaoli; Wang, Yueyue; Wei, Zhaoling; Chen, Meina

2018-05-01

Yttrium-doped BaCeO3 is one of the most promising electrolyte candidates for solid oxide fuel cells because of its high ionic conductivity. Nd and Y co-doped BaCeO3 strategy is adopted for the further optimization of Y-doped BaCeO3 electrolyte properties. X-ray diffraction results indicate that the structure of BaCe0.8Y0.2-xNdxO3-δ (x = 0, 0.05, 0.1, 0.15) with orthorhombic perovskite phase becomes more symmetric with increasing Nd concentration. The scanning electron microscope observation demonstrates that the densification and grain size of the sintered pellets significantly enhance with the increase of Nd doping level. Whether in dry and humid hydrogen or air, the increase of Nd dopant firstly increases the conductivities of BaCe0.8Y0.2-xNdxO3-δ (x = 0, 0.05, 0.1, 0.15) and then decrease them after reaching the peak value at x = 0.05. Electrochemical impedance spectra at 350 °C can distinguish clearly the contribution of grain and grain boundary to total conductivity and the highest conductivity of BaCe0.8Y0.15Nd0.05O3-δ ascribes to the decrease in bulk and grain boundary resistances due to the synergistic effect of Nd and Y doping. The anode-supported single cell with BaCe0.8Y0.15Nd0.05O3-δ electrolyte shows an encouraging peak power density of 660 mW cm-2 at 700 °C, suggesting that BaCe0.8Y0.15Nd0.05O3-δ is a potential electrolyte material for the highly-efficient proton-conducting solid oxide fuel cell.

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 %

Improving efficiency of the entomopathogenic fungi by gamma irradiation versus the Mediterranean fruit fly ceratitis capitata wiedemann (Diptera: Tephritidae)

International Nuclear Information System (INIS)

Fadel, A.M.; Haggag, W.M.

2002-01-01

The efficiency of wild and irradiated biocontrol fungi, Beauvaria Bassiana (Blsamo) and Trichoderma Harzianum (Rafai) on the Mediterranean Fruit fly Ceratitis Capitata (Wiedemann) was investigated. Applying wild B. bassiana and T. harzianum using spores suspension at different concentrations (10 8 , 10 6 and 10 4 colony-forming units), on the pupation medium (sand) or in drinking water, resulted in a significant reduction in adult emergence of pupae (1-2 day-old) and survival of produced adults. Meanwhile, the introduction of some isolates irradiated at 150 and 300 Gy significantly reduced adult emergence from pupae (1-2 day-old) and survival was greatly increased by isolates irradiated at 150 Gy of B. bassiana and at Gy in case of T. harzianum. Applying irradiated isolates as culture filtrate with the concentrations of 10, 50 and 100% to the pupation medium or in drinking water, resulted in a reduction of adult emergence and survival. The results revealed that bioagents B. bassiana and T. harzianum can be applied in the field to suppress the population of the mediterranean fruit fly ceratitis capitata and considered as entomopathogenic for controlling this pest

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

Highly efficient DNA-free gene disruption in the agricultural pest Ceratitis capitata by CRISPR-Cas9 ribonucleoprotein complexes.

Science.gov (United States)

Meccariello, Angela; Monti, Simona Maria; Romanelli, Alessandra; Colonna, Rita; Primo, Pasquale; Inghilterra, Maria Grazia; Del Corsano, Giuseppe; Ramaglia, Antonio; Iazzetti, Giovanni; Chiarore, Antonia; Patti, Francesco; Heinze, Svenia D; Salvemini, Marco; Lindsay, Helen; Chiavacci, Elena; Burger, Alexa; Robinson, Mark D; Mosimann, Christian; Bopp, Daniel; Saccone, Giuseppe

2017-08-30

The Mediterranean fruitfly Ceratitis capitata (medfly) is an invasive agricultural pest of high economic impact and has become an emerging model for developing new genetic control strategies as an alternative to insecticides. Here, we report the successful adaptation of CRISPR-Cas9-based gene disruption in the medfly by injecting in vitro pre-assembled, solubilized Cas9 ribonucleoprotein complexes (RNPs) loaded with gene-specific single guide RNAs (sgRNA) into early embryos. When targeting the eye pigmentation gene white eye (we), a high rate of somatic mosaicism in surviving G0 adults was observed. Germline transmission rate of mutated we alleles by G0 animals was on average above 52%, with individual cases achieving nearly 100%. We further recovered large deletions in the we gene when two sites were simultaneously targeted by two sgRNAs. CRISPR-Cas9 targeting of the Ceratitis ortholog of the Drosophila segmentation paired gene (Ccprd) caused segmental malformations in late embryos and in hatched larvae. Mutant phenotypes correlate with repair by non-homologous end-joining (NHEJ) lesions in the two targeted genes. This simple and highly effective Cas9 RNP-based gene editing to introduce mutations in C. capitata will significantly advance the design and development of new effective strategies for pest control management.

Development of attractant systems for trapping female Ceratitis capitata (Wied.) (Diptera: Tephritidae) in the Soconusco region, Chiapas, Mexico

International Nuclear Information System (INIS)

Montoya, P.; Miranda, H.; Paxtian, J.; Celedonio, H.; Orozco, D.

1999-01-01

With the aim of developing a system of attractants and trapping to optimize the capture of female Mediterranean fruit flies, Ceratitis capitata (Wied.) as well as other fruit flies, six experiments were carried out during the period 1994-1997, in a sterile-insect release zone in the Soconusco region of Chiapas, Mexico. Relating to the system of attractants, the evaluation focused on the comparison of food attractants (i.e. ammonium acetate, putrescine and trimethylamine) with standard attractants, such as Trimedlure and liquid hydrolyzed protein. For the trapping system, dry traps (Jackson trap, Open bottom dry trap, etc.) as well as wet traps (McPhail trap, Tephri trap, etc.) were tested alternately with the different kinds of attractants. The experiments were performed in agrosystems of coffee and groves of citrus and mango. Results consistently showed that a combination of ammonium acetate + putrescine + trimethylamine was the best for the capture of female Ceratitis capitata (Wied.) when used in traps such as the OBDT and the plastic McPhail trap (IPMT), while for Anastrepha spp., the McPhail trap baited with liquid hydrolyzed protein still appears to be the best option, although the combination of ammonium acetate with putrescine was quite consistent in the trapping of A. obliqua and A. ludens in traps such as the IPMT. (author)

Origin of gigantic magnetostriction and crystal field effects in terbium dititanate

International Nuclear Information System (INIS)

Aleksandrov, I.V.; Lidskij, B.V.; Mamsurova, L.G.

1985-01-01

The temperature and magnetic field dependences of the magnetostriction and magnetization and the temperature dependences of the magnetic susceptibility, specific heat and lattice parameter are investigated experimentally in a broad range of temperature and field strength for polycrystalline and single crystal Tb 2 Ti 2 O 7 . A conclusion is drawn regarding the structure of the energy levels of Tb 3+ in Tb 2 Ti 2 O 7 . A qualitative and quantitative explanation of all observed magnetic effects, and in particular of gigantic magnetostriction in Tb 2 Ti 2 O 7 , is presented which is based on the crystal field theory. It is shown that the huge magnitude of the magnetostriction in terbium dititanate is due to the specificity of the energy spectrum of Tb 3+ in Tb 2 Ti 2 O 7

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

{sup 5}D{sub 3}{yields}{sup 7}F{sub J} emission of Tb doped sol-gel silica

Energy Technology Data Exchange (ETDEWEB)

Seed Ahmed, H.A.A.; Ntwaeaborwa, O.M.; Gusowski, M.A. [Department of Physics, University of the Free State, IB51, Box 339, Bloemfontein 9300 (South Africa); Botha, J.R. [Department of Physics, Nelson Mandela Metropolitan University, Box 77000, Port Elizabeth 6031 (South Africa); Kroon, R.E., E-mail: KroonRE@ufs.ac.za [Department of Physics, University of the Free State, IB51, Box 339, Bloemfontein 9300 (South Africa)

2012-05-15

Amorphous silica samples doped with 0.1 and 1 mol% of terbium (Tb) were synthesized by the sol-gel method. In addition to the green light associated with {sup 5}D{sub 4}{yields}{sup 7}F{sub J} transitions of Tb{sup 3+}, the sample containing 0.1 mol% also emitted blue light as a result of {sup 5}D{sub 3}{yields}{sup 7}F{sub J} transitions during photoluminescence (PL) measurements. As a result of concentration quenching this blue emission was not observed for the samples doped with the higher concentration (1 mol%). However the blue {sup 5}D{sub 3} {yields}{sup 7}F{sub J} emission was observed in the 1 mol% doped samples during cathodoluminescence (CL) measurements. Since a rough calculation indicated that the excitation rate in the CL system where the blue emission is observed may be similar to a laser PL system under conditions where the blue emission is not observed, the difference is attributed to the nature of the excitation sources. It is suggested that during the CL excitation incident electrons can reduce non-luminescent Tb{sup 4+} ions in the silica, substituting for Si{sup 4+} ions, to the excited (Tb{sup 3+}) Low-Asterisk state and that these are responsible for the blue emission, which does not occur during PL excitation.

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.

Electronic structure of surface-supported bis(phthalocyaninato) terbium(III) single molecular magnets.

Science.gov (United States)

Vitali, Lucia; Fabris, Stefano; Conte, Adriano Mosca; Brink, Susan; Ruben, Mario; Baroni, Stefano; Kern, Klaus

2008-10-01

The electronic structure of isolated bis(phthalocyaninato) terbium(III) molecules, a novel single-molecular-magnet (SMM), supported on the Cu(111) surface has been characterized by density functional theory and scanning tunneling spectroscopy. These studies reveal that the interaction with the metal surface preserves both the molecular structure and the large spin magnetic moment of the metal center. The 4f electron states are not perturbed by the adsorption while a strong molecular/metal interaction can induce the suppression of the minor spin contribution delocalized over the molecular ligands. The calculations show that the inherent spin magnetic moment of the molecule is only weakly affected by the interaction with the surface and suggest that the SMM character might be preserved.

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.

Sensitivity of Ceratitis capitata eggs irradiated in artificial diet and in mango fruits; Sensibilidade de ovos de Ceratitis capitata (WIED.,1824) irradiados em dieta artificial e em frutos de manga (Mangifera indica L.)

Energy Technology Data Exchange (ETDEWEB)

Raga, A.; Yasuoka, S.T.; Amorim, E.O.; Sato, M.E.; Suplicy Filho, N. [Instituto Biologico, Campinas, SP (Brazil); Faria, J.T. de [Delegacia Federal de Agricultura, Sao Paulo, SP (Brazil)

1996-01-01

The objective of this study was to establish gamma radiation doses required to prevent emergence of Ceratitis capitata adults, from irradiated eggs in artificial diet and mango fruits. Six-, twelve-, twenty-four-, and forty-eight-hour-old eggs were used. Artificial infestation by C. capitata was carried out in mangoes of Haden, Tommy and Keith cultivars. An increase of radiation resistance of C. capitata eggs was observed as a function of the embryonic development and a Probit 9 of 24.67 Gy was estimated for 48-hour-old eggs in artificial diet. No significant influence of mango fruits was found on the efficacy of irradiation. (author). 11 refs., 3 tabs.

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...

Folate Receptor Targeted Alpha-Therapy Using Terbium-149

CERN Document Server

Müller, Cristina; Haller, Stephanie; Dorrer, Holger; Köster, Ulli; Johnston, Karl; Zhernosekov, Konstantin; Türler, Andreas; Schibli, Roger

2014-01-01

Terbium-149 is among the most interesting therapeutic nuclides for medical applications. It decays by emission of short-range α-particles (Eα = 3.967 MeV) with a half-life of 4.12 h. The goal of this study was to investigate the anticancer efficacy of a 149Tb-labeled DOTA-folate conjugate (cm09) using folate receptor (FR)-positive cancer cells in vitro and in tumor-bearing mice. 149Tb was produced at the ISOLDE facility at CERN. Radiolabeling of cm09 with purified 149Tb resulted in a specific activity of ~1.2 MBq/nmol. In vitro assays performed with 149Tb-cm09 revealed a reduced KB cell viability in a FR-specific and activity concentration-dependent manner. Tumor-bearing mice were injected with saline only (group A) or with 149Tb-cm09 (group B: 2.2 MBq; group C: 3.0 MBq). A significant tumor growth delay was found in treated animals resulting in an increased average survival time of mice which received 149Tb-cm09 (B: 30.5 d; C: 43 d) compared to untreated controls (A: 21 d). Analysis of blood parameters rev...

Crystal structures of two mononuclear complexes of terbium(III nitrate with the tripodal alcohol 1,1,1-tris(hydroxymethylpropane

Directory of Open Access Journals (Sweden)

Thaiane Gregório

2017-02-01

Full Text Available Two new mononuclear cationic complexes in which the TbIII ion is bis-chelated by the tripodal alcohol 1,1,1-tris(hydroxymethylpropane (H3LEt, C6H14O3 were prepared from Tb(NO33·5H2O and had their crystal and molecular structures solved by single-crystal X-ray diffraction analysis after data collection at 100 K. Both products were isolated in reasonable yields from the same reaction mixture by using different crystallization conditions. The higher-symmetry complex dinitratobis[1,1,1-tris(hydroxymethylpropane]terbium(III nitrate dimethoxyethane hemisolvate, [Tb(NO32(H3LEt2]NO3·0.5C4H10O2, 1, in which the lanthanide ion is 10-coordinate and adopts an s-bicapped square-antiprismatic coordination geometry, contains two bidentate nitrate ions bound to the metal atom; another nitrate ion functions as a counter-ion and a half-molecule of dimethoxyethane (completed by a crystallographic twofold rotation axis is also present. In product aquanitratobis[1,1,1-tris(hydroxymethylpropane]terbium(III dinitrate, [Tb(NO3(H3LEt2(H2O](NO32, 2, one bidentate nitrate ion and one water molecule are bound to the nine-coordinate terbium(III centre, while two free nitrate ions contribute to charge balance outside the tricapped trigonal-prismatic coordination polyhedron. No free water molecule was found in either of the crystal structures and, only in the case of 1, dimethoxyethane acts as a crystallizing solvent. In both molecular structures, the two tripodal ligands are bent to one side of the coordination sphere, leaving room for the anionic and water ligands. In complex 2, the methyl group of one of the H3LEt ligands is disordered over two alternative orientations. Strong hydrogen bonds, both intra- and intermolecular, are found in the crystal structures due to the number of different donor and acceptor groups present.

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)

The contribution of formal genetic studies to the characterization of the Mediterranean fruit fly, Ceratitis capitata (Wied.)

International Nuclear Information System (INIS)

Malacrida, A.R.; Gasperi, G.; Baruffi, L.; Milani, R.

1990-01-01

Twenty-eight functional loci and four morphological gene markers have been assigned to five of the six linkage groups of the Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann). The linkage group labelling system, proposed by Saul and Roessler, has been adopted. Map distances, obtained for twenty markers, showed the marked loci to be distributed over wide map intervals in all five autosomal linkage groups. The available information appears adequate for determining the position of chromosomal characteristics peculiar to each chromosome. (author). 14 refs, 2 tabs

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)

Update of host plant list of Anastrepha fraterculus and Ceratitis capitata in Argentina

International Nuclear Information System (INIS)

Orono, Luis E.; Albornoz-Medina, Patricia; Nunez-Campero, Segundo; Nieuwenhove, Guido A. van; Bezdjian, Laura P.; Martin, Cristina B.; Schliserman, Pablo; Ovruski, Sergio M.

2006-01-01

The study displays a complete picture of the host range of the two economically important fruit fly species in Argentina, the native Anastrepha fraterculus (Wiedemann) (South American Fruit Fly) and the exotic Ceratitis capitata (Wiedemann) (Mediterranean Fruit Fly or Medfly). This work provides information on the fruit type of each plant species, associated tephritid species, habitat where the fruit was collected, geographical location of each fruit collection area (latitude, longitude, and altitude), phyto geographic regions where each area is located, as well as a general description of the landscape characteristics of those habitats where the fruit samples with fly larvae were collected. A complete, detailed bibliographic review was made in order to provide all the relevant information needed for host use in natural setting. (author)

Genetic or mechanical sexing system for the Mediterranean fruit fly, Ceratitis capitata (Wied.)

International Nuclear Information System (INIS)

Walder, J.M.M.

1990-01-01

A black puparium, monofactorial mutant was isolated in 1983 from a laboratory colony of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann). The mutant was used to construct a genetic sexing strain based on pupal sorting. Translocations were induced in wild male adults, 48 hours old, by gamma radiation (55 Gy; 60 Co). These males were crossed to black pupae females and produced two pupal sorting strains (T-44 and T-213) in 1987. These strains were lost after six generations. In another series of translocation inductions the strain T-87B was screened. Rearing the strain for eight generations in the laboratory provided no indication of instability in the strain. T-87B is now being mass reared. (author). 16 refs, 4 tabs

Update of host plant list of Anastrepha fraterculus and Ceratitis capitata in Argentina

Energy Technology Data Exchange (ETDEWEB)

Orono, Luis E.; Albornoz-Medina, Patricia; Nunez-Campero, Segundo; Nieuwenhove, Guido A. van; Bezdjian, Laura P.; Martin, Cristina B.; Schliserman, Pablo; Ovruski, Sergio M. [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Tucuman (Argentina). Planta Piloto de Procesos Industriales Microbiologicos y Biotecnologia. Div. Control Biologico de Plagas

2006-07-01

The study displays a complete picture of the host range of the two economically important fruit fly species in Argentina, the native Anastrepha fraterculus (Wiedemann) (South American Fruit Fly) and the exotic Ceratitis capitata (Wiedemann) (Mediterranean Fruit Fly or Medfly). This work provides information on the fruit type of each plant species, associated tephritid species, habitat where the fruit was collected, geographical location of each fruit collection area (latitude, longitude, and altitude), phyto geographic regions where each area is located, as well as a general description of the landscape characteristics of those habitats where the fruit samples with fly larvae were collected. A complete, detailed bibliographic review was made in order to provide all the relevant information needed for host use in natural setting. (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.

Hyperfine structure of the odd parity level system in the terbium atom

International Nuclear Information System (INIS)

Stefanska, D; Furmann, B

2017-01-01

Within this work new experimental results concerning the hyperfine structure ( hfs ) in the terbium atom are presented, concerning the odd parity levels system, hitherto only scarcely investigated (apart from the ground term). hfs constants A and B for 113 levels were determined for the first time, and for another 16 levels, which already occurred in our earlier works, supplementary results were obtained; additionally, our earlier results for 93 levels were compiled. The hfs of the odd parity levels was investigated using the method of laser induced fluorescence in a hollow cathode discharge. The hfs of 165 spectral lines, where the levels in question were involved as the upper levels, was recorded. Literature values of hfs constants of the even-parity lower levels (including our own earlier results) greatly facilitated the present data evaluation. (paper)

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.

Isolation and identification of some Bacillus thuringiensis strains with insecticidal activity against Ceratitis capitata

International Nuclear Information System (INIS)

Majdoub, Nihed

2010-01-01

The aims of the present work is to study the effect of toxins (delta-endotoxins), extracted from different strains of Bacillus thuringiensis on Ceratitis capitata, a devastating of citrus and fruit trees. Strains of B. thuringiensis were isolated from the mud of Sebket Sejoumi. Among 70 isolates tested, 15 showed a significant identicalness activity in which 5 isolates led to mortality rates ≥ 90 pour cent . These mortality rates are caused by endotoxins of B. thuringiensis. Analysis of proteins profiles of different isolates of B. thuringiensis revealed variability between them. The preliminary results of this study encourage us towards the characterization of the insecticidal activity produced by B. thuringiensis strains for large scale application.

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)

Identification of pheromone components and their binding affinity to the odorant binding protein CcapOBP83a-2 of the Mediterranean fruit fly, Ceratitis capitata

Czech Academy of Sciences Publication Activity Database

Siciliano, P.; He, X. L.; Woodcock, C.; Pickett, J. A.; Field, L. M.; Birkett, M. A.; Kalinová, Blanka; Gomulski, L. M.; Scolari, F.; Gasperi, G.; Malacrida, A. R.; Zhou, J. J.

2014-01-01

Roč. 48, May (2014), s. 51-62 ISSN 0965-1748 Institutional support: RVO:61388963 Keywords : medfly * Ceratitis capitata * olfaction * odorant binding protein * pheromone binding protein * pheromone * binding studies * protein expression * electroantennography * GC-EAG * fluorescence displacement Subject RIV: CE - Biochemistry Impact factor: 3.450, year: 2014

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

A review of hymenopterous parasitoid guilds attacking Anastrepha spp. and Ceratitis capitata (Diptera: Tephritidae) in Argentina

Energy Technology Data Exchange (ETDEWEB)

Ovruski, Sergio M.; Orono, Luis E.; Nunez-Campero, Segundo; Schliserman, Pablo; Albornoz-Medina, Patricia; Bezdjian, Laura P.; Nieuwenhove, Guido A. Van; Martin, Cristina B. [Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Tucuman (Argentina). Planta Piloto de Procesos Industriales Microbiologicos y Biotecnologia. Div. Control Biologico de Plagas

2006-07-01

This study provides detailed information on the diversity, abundance, guilds, host plant and host fly ranges, distribution, and taxonomic status of hymenopterous parasitoid species associated with Ceratitis capitata (Wiedemann) and Anastrepha spp. (A. fraterculus (Wiedemann) and A. schultzi Blanchard) in Argentina. Moreover, the article also argues future needs regarding the use of some parasitoid species as an alternative tool in fruit fly management programs of the National Fruit Fly Control and Eradication Program (PROCEM-Argentina). Data used for this work were obtained from numerous old and recent published articles on fruit fly parasitoids in Argentina. (author)

A review of hymenopterous parasitoid guilds attacking Anastrepha spp. and Ceratitis capitata (Diptera: Tephritidae) in Argentina

International Nuclear Information System (INIS)

Ovruski, Sergio M.; Orono, Luis E.; Nunez-Campero, Segundo; Schliserman, Pablo; Albornoz-Medina, Patricia; Bezdjian, Laura P.; Nieuwenhove, Guido A. Van; Martin, Cristina B.

2006-01-01

This study provides detailed information on the diversity, abundance, guilds, host plant and host fly ranges, distribution, and taxonomic status of hymenopterous parasitoid species associated with Ceratitis capitata (Wiedemann) and Anastrepha spp. (A. fraterculus (Wiedemann) and A. schultzi Blanchard) in Argentina. Moreover, the article also argues future needs regarding the use of some parasitoid species as an alternative tool in fruit fly management programs of the National Fruit Fly Control and Eradication Program (PROCEM-Argentina). Data used for this work were obtained from numerous old and recent published articles on fruit fly parasitoids in Argentina. (author)

Sterilization by cobalt 60 of the mediterranean fruit fly Ceratitis Capitate Wied

International Nuclear Information System (INIS)

Dimundu Puena, I.; Cirio, Ugo.

1978-01-01

Ceratitis capitata have been irradiated with 2, 4, 6 and 10 Krad of a Co-60 gamma irradiator at 300 rad/min flow. Following results have been obtained: abundant and regular egg laid at 1 to 2 krads, reduced but regular egg laid at 4 krads and total sterility from 6 krads. The 10 krads irradiated insects exhibit satisfactory life time and activity. The 6 and above krads irradiated females are completely sterile but have the laid reflex. The 8 krads irradiated males exhibit sexual strength comparable to that of normal males. Males fertility is decreased with increasing irradiation dose, eggs obtained with normal female have fertility of less than 1 % for doses above 7 krads. However it appears that at 8 krads dose, some males can form again normal spermatozoids after 20 to 30 days. The recommended irradiation dose is 10 krads

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.)

Terbium fluorescence as a sensitive, inexpensive probe for UV-induced damage in nucleic acids

International Nuclear Information System (INIS)

El-Yazbi, Amira F.; Loppnow, Glen R.

2013-01-01

Graphical abstract: -- Highlights: •Simple, inexpensive, mix-and-read assay for positive detection of DNA damage. •Recognition of undamaged DNA via hybridization to a hairpin probe. •Terbium(III) fluorescence reports the amount of damage by binding to ssDNA. •Tb/hairpin is a highly selective and sensitive fluorescent probe for DNA damage. -- Abstract: Much effort has been focused on developing methods for detecting damaged nucleic acids. However, almost all of the proposed methods consist of multi-step procedures, are limited, require expensive instruments, or suffer from a high level of interferences. In this paper, we present a novel simple, inexpensive, mix-and-read assay that is generally applicable to nucleic acid damage and uses the enhanced luminescence due to energy transfer from nucleic acids to terbium(III) (Tb 3+ ). Single-stranded oligonucleotides greatly enhance the Tb 3+ emission, but duplex DNA does not. With the use of a DNA hairpin probe complementary to the oligonucleotide of interest, the Tb 3+ /hairpin probe is applied to detect ultraviolet (UV)-induced DNA damage. The hairpin probe hybridizes only with the undamaged DNA. However, the damaged DNA remains single-stranded and enhances the intrinsic fluorescence of Tb 3+ , producing a detectable signal directly proportional to the amount of DNA damage. This allows the Tb 3+ /hairpin probe to be used for sensitive quantification of UV-induced DNA damage. The Tb 3+ /hairpin probe showed superior selectivity to DNA damage compared to conventional molecular beacons probes (MBs) and its sensitivity is more than 2.5 times higher than MBs with a limit of detection of 4.36 ± 1.2 nM. In addition, this probe is easier to synthesize and more than eight times cheaper than MBs, which makes its use recommended for high-throughput, quantitative analysis of DNA damage

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.)

Luminescent features of sol–gel derived rare-earth multi-doped oxyfluoride nano-structured phosphors for white LED application

International Nuclear Information System (INIS)

Gouveia-Neto, A.S.; Silva, A.F. da; Bueno, L.A.; Costa, E.B. da

2012-01-01

Rare-earth doped oxyfluoride 75SiO 2 :25PbF 2 nano-structured phosphors for white-light-emitting diodes were synthesized by thermal treatment of precursor sol–gel derived glasses. Room temperature luminescence features of Eu 3+ , Sm 3+ , Tb 3+ , Eu 3+ /Tb 3+ , and Sm 3+ /Tb 3+ ions incorporated into low-phonon-energy PbF 2 nanocrystals dispersed in the aluminosilicate glass matrix and excited with UV light emitting diode were investigated. The luminescence spectra exhibited strong emission signals in the red (600, 610, 625, and 646 nm), green (548 and 560 nm), and blue (485 nm) wavelength regions. White-light emission was observed in Sm/Tb and Eu/Tb double-doped activated phosphors employing UV-LED excitation at 395 nm. The dependence of the luminescence emission intensities upon annealing temperature and rare-earth concentration was also examined. The results indicated that there exist optimum annealing temperature and activator ion concentration in order to obtain intense visible emission light with high color rendering index. The study suggests that the nanocomposite phosphor based upon 75SiO 2 :25PbF 2 host herein reported is a promising contender for white-light LED applications. - Highlights: ► White-light emission in double-doped activated phosphors employing UV-LED excitation. ► Luminescent features of europium, samarium, and terbium in nanocrystals dispersed in aluminosilicate glass. ► New nanocomposite phosphor host for white-light LED applications.

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.

Area-Wide Suppression of the Mediterranean Fruit Fly, Ceratitis capitata, and the Oriental Fruit Fly, Bactrocera dorsalis, in Kamuela, Hawaii

OpenAIRE

Vargas, Roger I.; Pi?ero, Jaime C.; Mau, Ronald F. L.; Jang, Eric B.; Klungness, Lester M.; McInnis, Donald O.; Harris, Ernest B.; McQuate, Grant T.; Bautista, Renato C.; Wong, Lyle

2010-01-01

The United States Department of Agriculture's Agricultural Research Service initiated an area-wide fruit fly management program in Hawaii in 2000. The first demonstration site was established in Kamuela, Hawaii, USA. This paper documents suppression of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), and the oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), in a 40 km2 area containing urban, rural and agricultural zones during a 6 year period. The suppressio...

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)

Construction of the energy matrix for complex atoms. Part VIII: Hyperfine structure HPC calculations for terbium atom

Science.gov (United States)

Elantkowska, Magdalena; Ruczkowski, Jarosław; Sikorski, Andrzej; Dembczyński, Jerzy

2017-11-01

A parametric analysis of the hyperfine structure (hfs) for the even parity configurations of atomic terbium (Tb I) is presented in this work. We introduce the complete set of 4fN-core states in our high-performance computing (HPC) calculations. For calculations of the huge hyperfine structure matrix, requiring approximately 5000 hours when run on a single CPU, we propose the methods utilizing a personal computer cluster or, alternatively a cluster of Microsoft Azure virtual machines (VM). These methods give a factor 12 performance boost, enabling the calculations to complete in an acceptable time.

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.

Synthesis and crystal structure of terbium(III) meta-oxoborate Tb(BO{sub 2}){sub 3} ({identical_to} TbB{sub 3}O{sub 6}); Synthese und Kristallstruktur von Terbium(III)-meta-Oxoborat Tb(BO{sub 2}){sub 3} ({identical_to} TbB{sub 3}O{sub 6})

Energy Technology Data Exchange (ETDEWEB)

Nikelski, Tanja; Schleid, Thomas [Institut fuer Anorganische Chemie der Universitaet Stuttgart (Germany)

2003-06-01

The terbium meta-oxoborate Tb(BO{sub 2}){sub 3} ({identical_to} TbB{sub 3}O{sub 6}) is obtained as single crystals by the reaction of terbium, Tb{sub 4}O{sub 7} and TbCl{sub 3} with an excess of B{sub 2}O{sub 3} in gastight sealed platinum ampoules at 950 C after three weeks. The compound appears to be air- and water-resistant and crystallizes as long, thin, colourless needles which tend to growth-twinning due to their marked fibrous habit. The crystal structure of Tb(BO{sub 2}){sub 3} (orthorhombic, Pnma; a = 1598.97(9), b = 741.39(4), c = 1229.58(7) pm; Z = 16) contains strongly corrugated oxoborate layers {sub {infinity}}{sup 2}{l_brace}(BO{sub 2}){sup -}{r_brace} built of vertex-linked [BO{sub 4}]{sup 5-} tetrahedra (d(B-O) = 143 - 154 pm, and angsph;(O-B-O) = 102-115 ) which spread out parallel (100). The four crystallographically different Tb{sup 3+} cations all exhibit coordination numbers of eight towards the oxygen atoms (d(Tb-O) = 228-287 pm). The corresponding metal cation polyhedra [TbO{sub 8}]{sup 13+} too convene to layers (composition: {sub {infinity}}{sup 2}{l_brace}(Tb{sub 2}O{sub 11}){sup 16-}{r_brace}) which are likewise oriented parallel to the (100) plane. (Abstract Copyright [2003], Wiley Periodicals, Inc.) [German] Das Terbium-meta-Oxoborat Tb(BO{sub 2}){sub 3} ({identical_to} TbB{sub 3}O{sub 6}) entsteht einkristallin bei der Reaktion von Terbium, Tb{sub 4}O{sub 7} und TbCl{sub 3} mit einem Ueberschuss von B{sub 2}O{sub 3} in gasdicht verschlossenen Platinampullen nach drei Wochen bei 950 C. Die Verbindung ist luft- und wasserstabil und faellt in langen, duennen, farblosen Nadeln an, die aufgrund ihres ausgepraegt faserigen Habitus zur Wachstumsverzwillingung neigen. Die Kristallstruktur von Tb(BO{sub 2}){sub 3} (orthorhombisch, Pnma; a = 1598, 97(9), b = 741, 39(4), c = 1229, 58(7) pm; Z = 16) enthaelt parallel (100) verlaufende, stark gewellte Oxoborat-Schichten {sub {infinity}}{sup 2}{l_brace}(BO{sub 2}){sup -}{r_brace} aus

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.

Photoluminescence from a Tb-doped photonic crystal microcavity for white light generation

International Nuclear Information System (INIS)

Li Yigang; Almeida, Rui M

2010-01-01

Terbium-doped one-dimensional triple microcavities have been prepared by sol-gel processing. The photoluminescence (PL) of Tb 3+ ions outside a microcavity structure, when excited by blue laser light at 488 nm, consisted of three distinct peaks at 542, 587 and 619 nm. When embedded in the microcavities, the three Tb 3+ PL peaks were enhanced, balanced and broadened by the photonic crystal structure and combined into a continuous broad band. An analysis in the CIE colour space showed that white light can be obtained by mixing the modified Tb 3+ PL with the blue exciting light, while this is impossible with the original PL profile. This novel technique may improve white light generation by enhancing and modifying the spontaneous emission of current phosphors. It may also lead to the development of new rare-earth phosphor materials based on 4f-4f transitions, able to generate white light more efficiently, via simpler and cheaper alternatives to the current phosphor compositions. A novel configuration to combine this kind of structure with a white light-emitting-diode (LED) is also proposed.

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.)

Electric Field-Assisted Pressureless Sintering of Ceramic Protonic Conductors

DEFF Research Database (Denmark)

Muccillo, R.; Esposito, Vincenzo; Zanetti De Florio, Daniel

2017-01-01

Gadolinium, yttrium and samarium-doped barium cerate (BCGd, BCY and BCSm, respectively) polycrystalline green pellets were submitted to electric field-assisted pressureless sintering experiments isothermally in the temperature range 800-1200oC under 100-200 V cm-1 electric fields, limiting to 1-5...

Sensitive luminescent determination of DNA using the terbium(III)-difloxacin complex

International Nuclear Information System (INIS)

Yegorova, Alla V.; Scripinets, Yulia V.; Duerkop, Axel; Karasyov, Alexander A.; Antonovich, Valery P.; Wolfbeis, Otto S.

2007-01-01

The interaction of the terbium-difloxacin complex (Tb-DFX) with DNA has been examined by using UV-vis absorption and luminescence spectroscopy. The Tb-DFX complex shows an up to 85-fold enhancement of luminescence intensity upon titration with DNA. The long decay times allow additional detection schemes like time-resolved measurements in microplate readers to enhance sensitivity by off-gating short-lived background luminescence. Optimal conditions are found at equimolar concentrations of Tb 3+ and DFX (0.1 or 1 μM) at pH 7.4. Under these conditions, the luminescence intensity is linearly dependent on the concentration of ds-DNAs and ss-DNA between 1-1500 ng mL -1 and 4.5-270 ng mL -1 , respectively. The detection limit is 0.5 ng mL -1 for ds-DNAs and 2 ng mL -1 for ss-DNA. The mechanism for the luminescence enhancement was also studied

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...

Monoxides of small terbium clusters: A density functional theory investigation

Energy Technology Data Exchange (ETDEWEB)

Zhang, G. L.; Yuan, H. K., E-mail: yhk10@swu.edu.cn; Chen, H.; Kuang, A. L.; Li, Y.; Wang, J. Z.; Chen, J. [School of Physical Science and Technology, Southwest University, Chongqing 400715 (China)

2014-12-28

To investigate the effect of oxygen atom on the geometrical structures, electronic, and magnetic properties of small terbium clusters, we carried out the first-principles calculations on Tb{sub n}O (n = 1-14) clusters. The capping of an oxygen atom on one trigonal-facet of Tb{sub n} structures is always favored energetically, which can significantly improve the structural stability. The far-infrared vibrational spectroscopies are found to be different from those of corresponding bare clusters, providing a distinct signal to detect the characteristic structures of Tb{sub n}O clusters. The primary effect of oxygen atom on magnetic properties is to change the magnetic orderings among Tb atoms and to reduce small of local magnetic moments of the O-coordinated Tb atoms, both of which serve as the key reasons for the experimental magnetic evolution of an oscillating behavior. These calculations are consistent with, and help to account for, the experimentally observed magnetic properties of monoxide Tb{sub n}O clusters [C. N. Van Dijk et al., J. Appl. Phys. 107, 09B526 (2010)].

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.

Evaluating United States and world consumption of neodymium, dysprosium, terbium, and praseodymium in final products

Science.gov (United States)

Hart, Matthew

This paper develops scenarios of future rare-earth-magnet metal (neodymium, dysprosium, terbium, and praseodymium) consumption in the permanent magnets used in wind turbines and hybrid electric vehicles. The scenarios start with naive base-case scenarios for growth in wind-turbine and hybrid-electric-vehicle sales over the period 2011 to 2020, using historical data for each good. These naive scenarios assume that future growth follows time trends in historical data and does not depend on any exogenous variable. Specifically, growth of each technological market follows historical time trends, and the amount of rare earths used per unit of technology remains fixed. The chosen reference year is 2010. Implied consumptions of the rare earth magnet metals are calculated from these scenarios. Assumptions are made for the material composition of permanent magnets, the market share of permanent-magnet wind turbines and vehicles, and magnet weight per unit of technology. Different scenarios estimate how changes in factors like the material composition of magnets, growth of the economy, and the price of a substitute could affect future consumption. Each scenario presents a different method for reducing rare earth consumption and could be interpreted as potential policy choices. In 2010, the consumption (metric tons, rare-earth-oxide equivalent) of each rare-earth-magnet metal was as follows. Total neodymium consumption in the world for both technologies was 995 tons; dysprosium consumption was 133 tons; terbium consumption was 50 tons; praseodymium consumption was zero tons. The base scenario for wind turbines shows there could be strong, exponential growth in the global wind turbine market. New U.S. sales of hybrid vehicles would decline (in line with the current economic recession) while non-U.S. sales increase through 2020. There would be an overall increase in the total amount of magnetic rare earths consumed in the world. Total consumption of each rare earth in the short

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)

Determination of sertraline in pharmaceutical and biological samples using 1, 10-phenanthroline-terbium probe and silver nanoparticles enhanced fluorescence

Energy Technology Data Exchange (ETDEWEB)

Lotfi, Ali, E-mail: alilotfi67@gmail.com [Young Researchers and Elite Club, Tabriz Branch, Islamic Azad University, Tabriz (Iran, Islamic Republic of); Manzoori, Jamshid L. [Department of Chemistry, Tabriz Branch, Islamic Azad University, Tabriz (Iran, Islamic Republic of); Mohagheghi, Arash [Clinical Psychiatry Research Center, Tabriz University of Medical Sciences, Tabriz (Iran, Islamic Republic of)

2017-05-15

Sertraline is an antidepressant widely prescribed for major depressive disorders. In this contribution we report a novel, rapid and sensitive spectrofluorimetric technique, developed and validated for the determination of sertraline in pharmaceutical, human urine and human plasma samples, based on the fluorescence enhancement of the sertraline by 1, 10-phenanthroline-terbium probe with Ag nanoparticles (AgNPs). The effect of pH, buffer concentration, the order of addition of reagents, terbium and 1, 10-phenanthroline concentrations, and concentration of Ag nanoparticles (AgNPs) as well as reaction time on the fluorescence intensity were investigated and the optimum conditions were determined. The linear range for determination of sertraline was obtained as 0.001–3 mg L{sup −1}. The limit of detection (b+3s) and the limit of quantification was calculated as 2.9×10{sup −4} mg L{sup −1} and 9.8×10{sup −4} mg L{sup −1}, respectively. The interference effects of common excipients found in pharmaceutical preparations were studied. The presented technique was used to determine the sertraline in pharmaceutical samples, human urine and plasma as real samples. The presented method was indicated a comparable results with the standard analytical techniques for sertraline. Good linearity, reproducibility, recovery and limit of detection have made this method suitable for determination of sertraline in various types of samples.

Determination of sertraline in pharmaceutical and biological samples using 1, 10-phenanthroline-terbium probe and silver nanoparticles enhanced fluorescence

International Nuclear Information System (INIS)

Lotfi, Ali; Manzoori, Jamshid L.; Mohagheghi, Arash

2017-01-01

Sertraline is an antidepressant widely prescribed for major depressive disorders. In this contribution we report a novel, rapid and sensitive spectrofluorimetric technique, developed and validated for the determination of sertraline in pharmaceutical, human urine and human plasma samples, based on the fluorescence enhancement of the sertraline by 1, 10-phenanthroline-terbium probe with Ag nanoparticles (AgNPs). The effect of pH, buffer concentration, the order of addition of reagents, terbium and 1, 10-phenanthroline concentrations, and concentration of Ag nanoparticles (AgNPs) as well as reaction time on the fluorescence intensity were investigated and the optimum conditions were determined. The linear range for determination of sertraline was obtained as 0.001–3 mg L −1 . The limit of detection (b+3s) and the limit of quantification was calculated as 2.9×10 −4 mg L −1 and 9.8×10 −4 mg L −1 , respectively. The interference effects of common excipients found in pharmaceutical preparations were studied. The presented technique was used to determine the sertraline in pharmaceutical samples, human urine and plasma as real samples. The presented method was indicated a comparable results with the standard analytical techniques for sertraline. Good linearity, reproducibility, recovery and limit of detection have made this method suitable for determination of sertraline in various types of samples.

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)

Self-assembly of Terbium(III)-based metal-organic complexes with two-photon absorbing active

Science.gov (United States)

Li, Dandan; Shao, Nanqi; Sun, Xianshun; Zhang, Guocui; Li, Shengli; Zhou, Hongping; Wu, Jieying; Tian, Yupeng

2014-12-01

Hybrid complexes based on D-π-A type dyes p-aminostyryl-pyridinum and Terbium(III) complex anion (1, 2) have been synthesized by ionic exchange reaction. Meanwhile two different alkyl-substituted amino groups were used as electron donors in organic dyes cations. The synthesized complexes were characterized by element analysis. In addition, the structural features of them were systematic studied by single crystal X-ray diffraction analysis. Their linear properties have been systematically investigated by absorption spectra and fluorescence, the results show that the energy transfer takes place from the trans-4-[4‧-(N,N-diethylamino)styryl]-N-methyl pyridinium (2‧) cation to Tb(III). In addition, complex 2 exhibit a large two-photon absorption coefficient β: 0.044 cm/GW at 710 nm.

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)

Electric Field-Assisted Pressureless Sintering of Ceramic Protonic Conductors

DEFF Research Database (Denmark)

Muccillo, R.; Esposito, Vincenzo; de Florio, D. Z.

2017-01-01

Gadolinium, yttrium and samarium-doped barium cerate pressed pellets were submitted to flash sintering experiments isothermally in the temperature range 800-1300oC under 200 V cm-1 electric field. The pellets were positioned inside a dilatometer furnace with Pt-Ir electrodes connected either to a...

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)

Synthesis and characterization of magnetic nanoparticles of oxides for dual MnFe{sub 2}O{sub 4} bioseparation, stabilized in fatty acid and the system chitosan - Eu(TTA){sub 3}(TPPO){sub 2}. Studies on the influence of doping with Gd{sup 3+}, Tb{sup 3+}, Ho{sup 3+} e Eu{sup 3+} in structural and magnetic properties; Sintese e caracterizacao de nanoparticulas magneticas de oxidos duplos de MnFe{sub 2}O{sub 4} para biosseparacao, estabilizadas em acido graxo e recobertas pelo sistema quitosana - Eu(TTA){sub 3}(TPPO){sub 2}. Estudo da influencia da dopagem com Gd{sup 3+}, Tb{sup 3+}, Ho{sup 3+} e Eu{sup 3+} nas propriedades estruturais e magneticas

Energy Technology Data Exchange (ETDEWEB)

Kovacs, Thelma Antunes Rodrigues

2014-07-01

This work was synthesized and characterized ferrite magnetic nanoparticles manganese, using the chemical coprecipitation method. By varying the heating time under 98°C (0, 10,20,40,60 3 80 minutes), the molar percentage of doping (1, 3, 5, 7, and 10%), gadolinium, europium, terbium and holmium. Magnetic ferrite nanoparticles and manganese ferrite doped with manganese were synthesized by coprecipitation method starting with chloride solutions of metals (iron (III), manganese (II), europium (III), gadolinium (III), terbium (III) and holmium (III)) and NaOH 5mol.L{sup -1} as precipitating agent. The magnetic nanoparticles were characterized by scanning electron microscopy, infrared spectroscopy, X-ray diffraction, magnetization curves, and thermal analysis. Most of manganese ferrite particles showed superparamagnetic behavior. After the characterization it was found that the samples synthesized manganese ferrite with more than 40 minutes heating time, crystal structure showed the characteristic pattern of the inverted manganese ferrite spinel type. The stabilization of the samples in oleic acid nanoparticles produced with a hydrophobic outer layer and facilitated by coating chitosan biopolymer, since this has a positive charge. Among the doped samples there was no significant change in the magnetic behavior. Several techniques for characterizing these materials have been used such as X-ray diffraction spectrum in the infrared region, magnetization curves and thermal analysis. The resins were tested as magnetic material for the separation of biological materials. In this paper, are used as biological targets separation of bovine serum albumin. (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.

Solid-phase synthesis of compounds of europium and terbium with nitrogen-containing heterocyclic compounds under mechanical activation

International Nuclear Information System (INIS)

Kalinovskaya, I.V.; Karasev, V.E.

2000-01-01

Effect of solvents and parameters of mechanical treatment on basic regularities of synthesis of rare earth compounds with nitrogen-containing heterocyclic compounds is studied. It is shown that interaction on europium (3) and terbium (3) nitrates with nitrogen-containing heterocyclic compounds leads to formation of compounds of Ln(NO 3 )·2D composition, where Ln=Eu, Tb; D=2,2-dipyridyl, 1,10-phenanthroline, diphenylguanidine. Effect of conditions of mechanical treatment and different additions on process and yield of products is studied. Compounds prepared are characterized by the methods of chemical element analysis, IR spectroscopy and luminescent spectroscopy [ru

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.

Size relationships of different body parts in the three dipteran species Drosophila melanogaster, Ceratitis capitata and Musca domestica.

Science.gov (United States)

Siomava, Natalia; Wimmer, Ernst A; Posnien, Nico

2016-06-01

Body size is an integral feature of an organism that influences many aspects of life such as fecundity, life span and mating success. Size of individual organs and the entire body size represent quantitative traits with a large reaction norm, which are influenced by various environmental factors. In the model system Drosophila melanogaster, pupal size and adult traits, such as tibia and thorax length or wing size, accurately estimate the overall body size. However, it is unclear whether these traits can be used in other flies. Therefore, we studied changes in size of pupae and adult organs in response to different rearing temperatures and densities for D. melanogaster, Ceratitis capitata and Musca domestica. We confirm a clear sexual size dimorphism (SSD) for Drosophila and show that the SSD is less uniform in the other species. Moreover, the size response to changing growth conditions is sex dependent. Comparison of static and evolutionary allometries of the studied traits revealed that response to the same environmental variable is genotype specific but has similarities between species of the same order. We conclude that the value of adult traits as estimators of the absolute body size may differ among species and the use of a single trait may result in wrong assumptions. Therefore, we suggest using a body size coefficient computed from several individual measurements. Our data is of special importance for monitoring activities of natural populations of the three dipteran flies, since they are harmful species causing economical damage (Drosophila, Ceratitis) or transferring diseases (Musca).

Courtship behavior of different wild strains of Ceratitis Capitata (Diptera: Tephritidae)

International Nuclear Information System (INIS)

Briceno, D.; Eberhard, W.; Vilardi, J.; Cayol, J.-P.; Shelly, T.

2007-01-01

This study documents differences in the courtship behavior of wild strains of Ceratitis capitata (Wiedemann) from Madeira (Portugal), Hawaii (U.S.A.), Costa Rica, and Patagonia (Argentina). Some traits showed large variations and others substantial overlaps. The angle at which the male faced toward the female at the moment of transition from continuous wing vibration and intermittent buzzing changed very little during the course of courtship in all strains, but males from Madeira tended to face more directly toward the female than other males. Females tended to look more, and more directly, toward the males as courtship progressed in all strains. The distance between male and female tended to decrease as courtship proceeded in all strains, but the distances at which males initiated continuous vibration, intermittent buzzing, and jumped onto the female were relatively less variable between strains, except for the strain from Costa Rica. Flies of Madeira courted for longer and the male moved his head and buzzed his wings longer than the other strains. (author) [es

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

Native and introduced host plants of Anastrepha fraterculus and Ceratitis capitata (Diptera: Tephritidae) in northwestern Argentina.

Science.gov (United States)

Ovruski, Sergio; Schliserman, Pablo; Aluja, Martín

2003-08-01

Wild or commercially grown, native and exotic fruit were collected in 30 localities in the Tucumán province (NW Argentina) from January 1990 to December 1995 to determine their status as hosts of Anastrepha fraterculus (Wiedemann) and/or Ceratitis capitata (Wiedemann), the only two fruit fly species of economic and quarantine importance in Argentina. A total of 84,094 fruit (3,466.1 kg) representing 33 species (7 native and 26 exotic) in 15 plant families were sampled. We determined the following 17 host plant associations: Annona cherimola Miller (Annonaceae), Citrus paradisi Macfadyn (Rutaceae), Diospyros kaki L. (Ebenaceae), Eugenia uniflora L., Psidium guajava L., Myrcianthes pungens (Berg) Legrand (Myrtaceae), Ficus carica L. (Moraceae), Juglans australis Grisebach (Juglandaceae), Mangifera indica L. (Anacardiaceae), Eriobotrya japonica (Thunb.) Lindl., Prunus armeniaca L., P. domestica L., and P. persica (L.) Batsch (Rosaceae) were infested by both A. fraterculus and C. capitata. Citrus aurantium L., Citrus reticulata Blanco, Citrus sinensis (L.) Osbeck (Rutaceae), and Passiflora caerulea L. (Passifloraceae) were only infested by Ceratitis capitata. Out of a total of 99,627 adults that emerged from pupae, 69,180 (approximately 69.5%) were Anastrepha fraterculus, 30,138 (approximately 30.2%) were C. capitata, and 309 (approximately 0.3%) were an unidentified Anastrepha species. Anastrepha fraterculus predominated in native plant species while C. capitata did so in introduced species. Infestation rates (number of larvae/kg of fruit) varied sharply from year to year and between host plant species (overall there was a significant negative correlation between fruit size and infestation level). We provide information on fruiting phenology of all the reported hosts and discuss our findings in light of their practical (e.g., management of A. fraterculus and C. capitata in citrus groves) implications.

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)

Luminescent hybrid films obtained by covalent grafting of terbium complex to silica network

International Nuclear Information System (INIS)

Liu Fengyi; Fu Lianshe; Wang Jun; Liu Ze; Li Huanrong; Zhang Hongjie

2002-01-01

Luminescent hybrid thin films consisting of terbium complex covalently bonded to a silica-based network have been obtained in situ via a sol-gel approach. A new monomer, N-(4-benzoic acid-yl), N'-(propyltriethoxysilyl)urea (PABI), has been synthesized by grafting isocyanatopropyltriethoxysilane (ICPTES) to p-aminobenzoic acid and characterized by 1 H NMR, IR and MS. The monomer acts as a ligand for Tb 3+ ion and as a sol-gel precursor. Band emission from Tb 3+ ion due to an efficient ligand-to-metal energy transfer was observed by UV excitation. The decay curves of Tb 3+ in the hybrid films were measured. The energy difference between the triplet state energy of PABI and the 5 D 4 level of Tb 3+ ion falls in the exciting range to sensitize Tb 3+ ion fluorescence

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.

Treatment post harvest of Citrus sinensis infested with Ceratitis capitata (Wied., 1824) (Diptera: Tephritidae) using gamma radiation

International Nuclear Information System (INIS)

Albergaria, Nuno M.M. Soares de; Bortoli, Sergio A. de; Doria, Hayda O.S.; Arthur, Valter

2009-01-01

This work was carried out to evaluate the effect of irradiation on fruit fly (Ceratitis capitata) eggs and larvae (first, second, third instars), in 'Valencia' oranges; and evaluate the effect of the irradiation on the chemical composition of the fruits. Fruits were artificially infested with the immature stages of the fruit fly and treated with 0, 10, 20, 30, 40, 50, 100, 150 and 200 Gy Cobalt-60 doses. By the results obtained it is possible to conclude that: third instar larvae are more tolerant to irradiation treatments; the dose of 50 Gy causes sterility to the adults emerged from all immature stages irradiated. (author)

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

Nanostructured Layered Terbium Hydroxide Containing NASIDs: In Vitro Physicochemical and Biological Evaluations.

Science.gov (United States)

Gu, Qing-Yang; Qiu, Xiao; Liu, Jing-Jing; Fu, Min; Chao, Jian-Ping; Ju, Rui-Jun; Li, Xue-Tao

2018-08-01

Diclofenac sodium (abrr. DS) and indomethacin (abrr. IMC) have been intercalated into the layered terbium hydroxide (LTbH) by anion exchange method. Chemical compositions, thermostability, morphology, luminescence property, release behaviors and cytotoxic effects have been investigated. The DS molecules may embed between layers with a bilayered arrangement and the IMC may correspond to a monolayered arrangement. The Tb3+ luminescence in DS-LTbH and IMC-LTbH composites were enhanced compared with LTbH precusor and the luminescence intensity increases with the deprotonation degree. Drug release was measured with HPLC, and LTbH showed sustained release behavior on both drugs. Further In Vitro evaluation were carried out on cancer cells. Cytotoxic effect of LTbH was observed with a sulforhodamine B colorimetric assay on a variety of cancer cell lines, which revealed that the LTbH showed little cytotoxic effect. Results indicate LTbH may offer a potential vehicle as an effective drug delivery system along with diagnostic integration.

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.

Raman spectra of terbium trichloride, phosphorus pentachloride and their molten mixtures; Spektry kombinatsionnogo rasseyaniya sveta trikhlorida terbiya, pentakhlorida fosfora i ikh rasplavlennykh smesej

Energy Technology Data Exchange (ETDEWEB)

Salyulev, A B; Zakir' yanova, I D [UrO RAN, Inst. Vysokotemperaturnoj Ehlektrokhimii, Ekaterinburg (Russian Federation)

2008-03-15

Raman spectroscopy was used to study in situ the behavior of individual terbium trichloride and phosphorus pentachloride in different aggregative states as a function of temperature, and of solutions of PCl{sub 5} vapors in molten TbCl{sub 3}. A conclusion is drawn about their structure and the nature of phase transformations and chemical reactions in wide ranges of temperature and saturated vapor pressures.

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

Disinfestation of export oranges and tangerines (Citrus spp) against medfly Ceratitis capitata (Wied., 1824) (Diptera; Tephritidae) by gamma irradiation (Co-60)

International Nuclear Information System (INIS)

Costa, N.

1990-01-01

A gamma bean 650 cobalt-60 source was utilized for irradiation (0; 10; 50; 100; 200; 300; 400; 500; 750 and 1000 Gy) of fresh ripe fruits artificially interested by immature stages of Ceratitis capitata to determine the sterilizing and lethal doses. The sensorial and chemical analyses did not show any significant differences between the control and irradiated samples. Differences on loss of weight of oranges show that 500 and 1000 Gy doses were responsible for increasing the loss of water content. (author)

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

Tecnologia alternativa no controle de Ceratitis capitata e sua implicação na qualidade de frutos de Spondias purpurea

OpenAIRE

Oliveira, Flávia Queiroz de

2011-01-01

A ciriguela Spondias purpurea é uma frutífera tropical de importância vital para os agricultores do semi-árido do Brasil, porém tem como um dos fatores limitantes a ocorrência de moscas-das-frutas Ceratitis capitata (Diptera: Tephritidae). Diversos trabalhos têm discutido a aplicabilidade de produtos naturais, como óleos essenciais, em programas de controle desta praga. No entanto, pouco se sabe sobre a eficiência dessa tática no controle de C. capitata, assim como o impacto dessa tecnologia ...

Some chemical elements in gamma irradiated adults of the mediterranean fruit fly , Ceratitis Capitata (WIED.)

International Nuclear Information System (INIS)

El-akhdar, E.A.H.

2005-01-01

The chemical analysis of the elemental compositions of both males and females of the Mediterranean fruit fly, Ceratitis capitata (Wied.), was conducted on adult flies irradiated in the full grown pupae with 50, 70, 90 and 110 Gray at different ages (newly emerged, 7 and 15 days old). The data revealed the presence of ten elements, three of which are major (Na, K and N), four are moderate (P, Ca, Fe and Mg) and three are minors (Zn, Mn and Cu). Their quantities, however, varied according to adult sex, age and radiation dose. In all cases, the major elements remained major, the moderate elements remained moderate and the minor elements remained minor although the elements of each group differed in their arrangement according to changes in their quantities

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.

Analysis of seasonal risk for importation of the Mediterranean fruit fly, Ceratitis capitate (Diptera: Tephritidae), via air passenger traffic arriving in Florida and California

OpenAIRE

Szyniszewska, A.M.; Leppla, N.C.; Huang, Z.; Tatem, A.J.

2016-01-01

The Mediterranean fruit fly, Ceratitis capitata (Wiedemann), is one of the most economically damaging pests in the world and has repeatedly invaded two major agricultural states in the United States, Florida and California, each time requiring costly eradication. The Mediterranean fruit fly gains entry primarily in infested fruit carried by airline passengers and, since Florida and California each receive about 13 million international passengers annually, the risk of Mediterranean fruit fly ...

Influence of different tropical fruits on biological and behavioral aspects of the Mediterranean fruit fly Ceratitis capitata (Wiedemann (Diptera, Tephritidae

Directory of Open Access Journals (Sweden)

Anne M. Costa

2011-09-01

Full Text Available Influence of different tropical fruits on biological and behavioral aspects of the Mediterranean fruit fly Ceratitis capitata (Wiedemann (Diptera, Tephritidae. Studies on Ceratitis capitata, a world fruit pest, can aid the implementation of control programs by determining the plants with higher vulnerability to attacks and plants able to sustain their population in areas of fly distribution. The objective of the present study was to evaluate the influence of eight tropical fruits on the following biological and behavioral parameters of C. capitata: emergence percentage, life cycle duration, adult size, egg production, longevity, fecundity, egg viability, and oviposition acceptance. The fruits tested were: acerola (Malpighia glabra L., cashew (Anacardium occidentale L., star fruit (Averrhoa carambola L., guava (Psidium guajava L., soursop (Annona muricata L., yellow mombin (Spondias mombin L., Malay apple (Syzygium malaccense L., and umbu (Spondias tuberosa L.. The biological parameters were obtained by rearing the recently hatched larvae on each of the fruit kinds. Acceptance of fruits for oviposition experiment was assessed using no-choice tests, as couples were exposed to two pieces of the same fruit. The best performances were obtained with guava, soursop, and star fruit. Larvae reared on cashew and acerola fruits had regular performances. No adults emerged from yellow mombin, Malay apple, or umbu. Fruit species did not affect adult longevity, female fecundity, or egg viability. Guava, soursop, and acerola were preferred for oviposition, followed by star fruit, Malay apple, cashew, and yellow mombin. Oviposition did not occur on umbu. In general, fruits with better larval development were also more accepted for oviposition.Influência de diferentes frutos tropicais em aspectos biológicos e comportamentais da mosca-das-frutas Ceratitis capitata (Wiedemann (Diptera, Tephritidae. Estudos em Ceratitis capitata, uma praga agrícola, pode auxiliar

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)

Polytene chromosome analysis in relation to genetic sex separation in the Mediterranean fruit fly, Ceratitis capitata (Wied.)

International Nuclear Information System (INIS)

Kerremans, P.; Busch-Petersen, E.

1990-01-01

The development of stable genetic sexing strains in the Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann), is hampered by the presence of low levels of male recombination. Such recombination may be reduced by minimizing the distance between the translocation breakpoint and the translocated 'sexing' allele. Cytogenetic analysis of mitotic/meiotic and polytene chromosomes could provide information on the selection of such potentially stable genetic sexing strains. Translocation breakpoints in two genetic sexing strains in the medfly, based on a white female/brown male pupal colour dimorphism, have been determined. Preliminary results are described and the advantages and limitations of polytene chromosome analysis for the isolation of stable genetic sexing strains of the medfly are discussed. (author). 31 refs

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