WorldWideScience

Sample records for borates

  1. Borates

    Science.gov (United States)

    Crangle, R.D.

    2013-01-01

    Four minerals represent 90 percent of the borates used by industry worldwide — the sodium borates (tincal and kernite), calcium borate (colemanite) and the sodium-calcium borate (ulexite). Borax is a white crystalline substance, chemically known as sodium tetraborate decahydrate, and is found naturally as the mineral tincal. Boric acid is a colorless crystalline solid sold in technical, national formulary and special quality grades as granules or powder and marketed most often as anhydrous boric acid. Deposits of borates are associated with volcanic activity and arid climates, with the largest economically viable deposits located in the Mojave Desert of the United States near Boron, CA, the Alpide belt in southern Asia and the Andean belt of South America.

  2. Borat vihastas ka rumeenlasi

    Index Scriptorium Estoniae

    2006-01-01

    Rumeenia mustlasküla Glod elanikud peavad endi solvamiseks viisi, kuidas neid ära kasutati Briti koomiku Sacha Baron Coheni loodud peategelasega USA filmi "Borat - kultuurialased õppetunnid Ameerikast abiks suursuguse Kasahstani riigi ülesehitamisel" võtetel

  3. Magnesium borate radiothermoluminescent detectors

    International Nuclear Information System (INIS)

    Kazanskaya, V.A.; Kuzmin, V.V.; Minaeva, E.E.; Sokolov, A.D.

    1974-01-01

    In the report the technology of obtaining polycrystalline magnesium borate activated by dysprosium is described briefly and the method of preparing the tabletted detectors from it is presented. The dependence of the light sum of the samples on the proportion of the components and on the sintering regime has shown that the most sensitive material is obtained at the proportion of boric anhydride and magnesium oxide 2.2-2.4 and at the dysprosium concentration about 1 milligram-atom per gram molecule of the base. The glow curve of such a material has a simple form with one peak the maximum of which is located at 190-200 0 C. The measurement of the main dosimetric characteristics of the magnesium borate tabletted detectors and the comparison with similar parmaeters of the lithium fluoride tabletted detectors have shown that at practically identical effective number the former detectors have the following substantial advantages: the sensitivity is ten-twenty times as large, they are substantially more technological on synthesis of the radiothermoluminophor and during the production of the tabletted detectors, they have a simple glow curve, they do not require the utilization of the thermocycling during the use. (author)

  4. Copper doped borate dosimeters revisited

    Energy Technology Data Exchange (ETDEWEB)

    Alajerami, Y.S.M. [Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Department of Medical Radiography, Al-Azhar University, Gaza Strip, Palestine (Country Unknown); Hashim, S., E-mail: suhairul@utm.my [Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Oncology Treatment Centre, Sultan Ismail Hospital, 81100 Johor Bahru (Malaysia); Ghoshal, S.K. [Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Bradley, D.A. [Centre for Nuclear and Radiation Physics, Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Mhareb, M. [Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Saleh, M.A. [Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); National Atomic Energy Commission (NATEC), Sana' a (Yemen)

    2014-11-15

    We render a panoramic overview on copper (Cu) doped borate dosimeters. Preparing a dosimeter by mixing specific materials with precise weights and methods is a never-ending quest. The recommended composition is highly decisive for accurate estimation of the absorbed dose, prediction of the biological outcome, determination of the treatment dose for radiation therapy and facilitation of personal monitoring. Based on these principles, the proposed dosimeter must cover a series of dosimetric properties to realize the exact results and assessment. The doped borate dosimeters indeed demonstrate attractive thermoluminescence (TL) features. Several dedicated efforts are attempted to improve the luminescence properties by doping various transition metals or rare-earth elements. The Cu ion being one of the preferred activators shows excellent TL properties as revealed via detail comparison with other dosimeters. Two oxide states of Cu (Cu{sup +} and Cu{sup ++}) with reasonable atomic number allow easy interaction with boron network. Interestingly, the intrinsic luminescent centers of borate lattice are in cross linked with that of Cu{sup +} ions. Thus, the activation of borate dosimeter with Cu ions for the enhancement of the TL sensitivity is recognized. These dosimeters reveal similar glow curves as the standard TLD-100 (LiF:Mg,Ti) one irrespective of the use of modifiers and synthesis techniques. They display high sensitivity, low fading, dose response linearity over wide range and practical minimum detectable dose. Furthermore, the effective atomic number being the most beneficial aspect (equivalent to that of human tissue) of borate dosimeters do not show any change due to Cu ion activations. The past development, major challenges, excitement, applications, recent progress and the future promises of Cu doped borate TL dosimeters are highlighted. - Highlights: • The manuscript gives a panoramic overview on copper doped borate dosimeters. • Cu ions activated

  5. Copper doped borate dosimeters revisited

    International Nuclear Information System (INIS)

    Alajerami, Y.S.M.; Hashim, S.; Ghoshal, S.K.; Bradley, D.A.; Mhareb, M.; Saleh, M.A.

    2014-01-01

    We render a panoramic overview on copper (Cu) doped borate dosimeters. Preparing a dosimeter by mixing specific materials with precise weights and methods is a never-ending quest. The recommended composition is highly decisive for accurate estimation of the absorbed dose, prediction of the biological outcome, determination of the treatment dose for radiation therapy and facilitation of personal monitoring. Based on these principles, the proposed dosimeter must cover a series of dosimetric properties to realize the exact results and assessment. The doped borate dosimeters indeed demonstrate attractive thermoluminescence (TL) features. Several dedicated efforts are attempted to improve the luminescence properties by doping various transition metals or rare-earth elements. The Cu ion being one of the preferred activators shows excellent TL properties as revealed via detail comparison with other dosimeters. Two oxide states of Cu (Cu + and Cu ++ ) with reasonable atomic number allow easy interaction with boron network. Interestingly, the intrinsic luminescent centers of borate lattice are in cross linked with that of Cu + ions. Thus, the activation of borate dosimeter with Cu ions for the enhancement of the TL sensitivity is recognized. These dosimeters reveal similar glow curves as the standard TLD-100 (LiF:Mg,Ti) one irrespective of the use of modifiers and synthesis techniques. They display high sensitivity, low fading, dose response linearity over wide range and practical minimum detectable dose. Furthermore, the effective atomic number being the most beneficial aspect (equivalent to that of human tissue) of borate dosimeters do not show any change due to Cu ion activations. The past development, major challenges, excitement, applications, recent progress and the future promises of Cu doped borate TL dosimeters are highlighted. - Highlights: • The manuscript gives a panoramic overview on copper doped borate dosimeters. • Cu ions activated technique in borate

  6. "Borat" kogus tubli hulga vaatajaid

    Index Scriptorium Estoniae

    2006-01-01

    Briti koomiku Sacha Baron Coheni loodud peategelasega USA film "Borat - kultuurialased õppetunnid Ameerikast abiks suursuguse Kasahstani riigi ülesehitamisel" kogus Eesti kinolevis avanädalavahetusel 12 487 vaatajat (taasiseseisvumisaja neljas tulemus)

  7. Tere tulemast Eestisse, Borat Sagdijev! / Triin Tael

    Index Scriptorium Estoniae

    Tael, Triin

    2006-01-01

    Briti koomiku Sacha Baron Coheni loodud peategelasega USA film "Borat - kultuurialased õppetunnid Ameerikast abiks suursuguse Kasahstani riigi ülesehitamisel" esilinastub Eesti kinodes. Lisaks "Juut, kes mängib juudivihkajaid", "Borat ei taha kuningannaga seksida", "Vaene solvatud Kasahstan"

  8. Borated aluminum alloy manufacturing technology

    International Nuclear Information System (INIS)

    Shimojo, Jun; Taniuchi, Hiroaki; Kajihara, Katsura; Aruga, Yasuhiro

    2003-01-01

    Borated aluminum alloy is used as the basket material of cask because of its light weight, thermal conductivity and superior neutron absorbing abilities. Kobe Steel has developed a unique manufacturing process for borated aluminum alloy using a vacuum induction melting method. In this process, aluminum alloy is melted and agitated at higher temperatures than common aluminum alloy fabrication methods. It is then cast into a mold in a vacuum atmosphere. The result is a high quality aluminum alloy which has a uniform boron distribution and no impurities. (author)

  9. Kes on Borat? / Timo Diener

    Index Scriptorium Estoniae

    Diener, Timo

    2006-01-01

    Eesti kinodesse on jõudnud briti koomiku Sacha Baron Coheni loodud peategelasega USA film "Borat - kultuurialased õppetunnid Ameerikast abiks suursuguse Kasahstani riigi ülesehitamisel" : režissöör Larry Charles. Filmi peaosalisest ja filmi seiklusrikkast võtteperioodist

  10. Ultrasonic relaxations in borate glasses

    International Nuclear Information System (INIS)

    D'Angelo, G.; Tripodo, G.; Carini, G.; Cosio, E.; Bartolotta, A.; Di Marco, G.

    2004-01-01

    The attenuation and velocity of ultrasonic waves of frequencies in the range from 10 to 70 MHz have been measured in M 2 O-B 2 O 3 borate glasses (M: Li or Ag) as a function of temperature between 15 and 350 K. The velocity of sound waves decreases with increasing temperature in all the glasses, the decrease as the temperature is increased is larger in glasses containing silver than in those with lithium. A broad relaxation peak characterises the attenuation behaviour of the lithium and silver borate glasses at temperatures below 100 K and is paralleled by a corresponding dispersive behaviour of the sound velocity. Above 100 K, the ultrasonic velocity shows a nearly linear behaviour regulated by the vibrational anharmonicity, which decreases with increasing content of modifier oxide and is smaller in lithium than in silver borates. These results suggest that the relaxation of structural defects and the anharmonicity of borate glasses are strongly affected by two parameters: the number of bridging bonds per network forming ion and the polarising power of network modifier ions which occupy sites in the existing interstices

  11. Degradable borate glass polyalkenoate cements.

    Science.gov (United States)

    Shen, L; Coughlan, A; Towler, M; Hall, M

    2014-04-01

    Glass polyalkenoate cements (GPCs) containing aluminum-free borate glasses having the general composition Ag2O-Na2O-CaO-SrO-ZnO-TiO2-B2O3 were evaluated in this work. An initial screening study of sixteen compositions was used to identify regions of glass formation and cement compositions with promising rheological properties. The results of the screening study were used to develop four model borate glass compositions for further study. A second round of rheological experiments was used to identify a preferred GPC formulation for each model glass composition. The model borate glasses containing higher levels of TiO2 (7.5 mol %) tended to have longer working times and shorter setting times. Dissolution behavior of the four model GPC formulations was evaluated by measuring ion release profiles as a function of time. All four GPC formulations showed evidence of incongruent dissolution behavior when considering the relative release profiles of sodium and boron, although the exact dissolution profile of the glass was presumably obscured by the polymeric cement matrix. Compression testing was undertaken to evaluate cement strength over time during immersion in water. The cements containing the borate glass with 7.5 mol % TiO2 had the highest initial compressive strength, ranging between 20 and 30 MPa. No beneficial aging effect was observed-instead, the strength of all four model GPC formulations was found to degrade with time.

  12. Crystallization of lithium borate glasses

    Science.gov (United States)

    Goktas, A. A.; Neilson, G. F.; Weinberg, M. C.

    1992-01-01

    The glass-forming ability and crystallization behavior of lithium borate compositions, in the diborate-to-metaborate-range, were studied. In particular, the nature and sequence of formation of crystalline phases and the tendency toward devitrification were investigated as functions of temperature, thermal history and batch composition. It was found that the sequence of crystalline phase formation was sensitive to all of the three latter factors, and it was observed that under certain conditions metastable defect structures of the metaborate can appear.

  13. Exoelectron emission from magnesium borate glass ceramics

    International Nuclear Information System (INIS)

    Kawamoto, Takamichi; Yanagisawa, Hideo; Nakamichi, Hiroshi; Kikuchi, Riichi; Kawanishi, Masaharu.

    1986-01-01

    Thermally stimulated exoelectron emission (TSEE) of a magnesium borate glass ceramics was investigated for its application to dosemetric use. It has been found that the TSEE glow patterns of the magnesium borate glass ceramics as well as a Li 2 B 4 O 7 glass ceramics depend on the kind of the radiation used and that the heat resistance of the magnesium borate glass ceramics is higher than that of the Li 2 B 4 O 7 glass ceramics. Therefore, the TSEE glow patterns of the magnesium borate glass ceramics indicate a possibility to be used as the dose measurement for each kind of radiation in the mixed radiation field. (author)

  14. Penetration of boron from topically applied borate solutions

    Science.gov (United States)

    Stan T. Lebow; Patricia K. Lebow; Steven A. Halverson

    2010-01-01

    Borate penetration relies on diffusion when borate and glycol-borate preservatives are applied to the surface of wood. This study evaluated the extent of borate penetration in framing lumber as a function of preservative formulation, wood moisture content, and diffusion time after treatment. In Phase I of the study, end-matched specimens were conditioned to target...

  15. Crystallization of bismuth borate glasses

    International Nuclear Information System (INIS)

    Bajaj, Anu; Khanna, Atul

    2009-01-01

    Bismuth borate glasses with Bi 2 O 3 concentration of 20-66 mol% were prepared by melt quenching and devitrified by heat treatment above their glass transition temperatures. All glasses show a strong tendency towards crystallization on annealing that increases with Bi 2 O 3 concentration. The crystalline phases formed on devitrification were characterized by FTIR absorption spectroscopy and DSC measurements. Our studies reveal that phases produced in glasses are strongly determined by initial glass composition and the two most stable crystalline phases are: Bi 3 B 5 O 12 and Bi 4 B 2 O 9 . The metastable BiBO 3 phase can also be formed by devitrification of glass with 50 mol% of Bi 2 O 3 . This phase is, however, unstable and decomposes into Bi 3 B 5 O 12 and Bi 4 B 2 O 9 on prolonged heat treatment.

  16. Repliik filmi "Borat" kohta / Urve Kirss

    Index Scriptorium Estoniae

    Kirss, Urve

    2007-01-01

    Briti koomiku Sacha Baron Coheni loodud peategelasega USA film "Borat - kultuurialased õppetunnid Ameerikast abiks suursuguse Kasahstani riigi ülesehitamisel" : režissöör Larry Charles. Vaataja mõtteid

  17. Separation of cesium from aqueous solutions using alkylated tetraaryl borates

    International Nuclear Information System (INIS)

    Feldmaier, F.

    1991-01-01

    The water solubility of cesium tetraaryl borates was lowered by introducing hydrophobic aliphatic side chains into corresponding acid-resistant fluorosubstituted tetraaryl borates. This improved cesium spearability both in precipitation and in extraction from aqueous solutions. (orig.) [de

  18. Bioactive borate glass coatings for titanium alloys.

    Science.gov (United States)

    Peddi, Laxmikanth; Brow, Richard K; Brown, Roger F

    2008-09-01

    Bioactive borate glass coatings have been developed for titanium and titanium alloys. Glasses from the Na(2)O-CaO-B(2)O(3) system, modified by additions of SiO(2), Al(2)O(3), and P(2)O(5), were characterized and compositions with thermal expansion matches to titanium were identified. Infrared and X-ray diffraction analyses indicate that a hydroxyapatite surface layer forms on the borate glasses after exposure to a simulated body fluid for 2 weeks at 37 degrees C; similar layers form on 45S5 Bioglass((R)) exposed to the same conditions. Assays with MC3T3-E1 pre-osteoblastic cells show the borate glasses exhibit in vitro biocompatibility similar to that of the 45S5 Bioglass((R)). An enameling technique was developed to form adherent borate glass coatings on Ti6Al4V alloy, with adhesive strengths of 36 +/- 2 MPa on polished substrates. The results show these new borate glasses to be promising candidates for forming bioactive coatings on titanium substrates.

  19. Calcination effect of borate-bearing hydroxyapatite on the mobility of borate.

    Science.gov (United States)

    Sasaki, Keiko; Toshiyuki, Kenta; Guo, Binglin; Ideta, Keiko; Hayashi, Yoshikazu; Hirajima, Tsuyoshi; Miyawaki, Jin

    2018-02-15

    Discharge from accidental nuclear power plants includes boric acid, which is used as a neutron absorbent in nuclear reactors. Co-precipitation of borate with hydroxyapatite (HAp), using Ca(OH) 2 , is known to be an effectively fast method for stabilization of borate as well as coexisting radioactive nuclides. To reduce bulky volume of solid residues after co-precipitation, calcination is necessary to investigate the chemical stability of targets. Calcination at 850°C resulted in the high crystalization of HAp with formation of xCaO·B 2 O 3 as a by-phase in which x increased with a decrease in the borate contents. After calcination, the lattice parameter a of HAp showed a reentrant curve and c showed a convex curve with an increase in borate contents. A dissolution assay revealed that calcination sometimes increases the borate moiety and that the acceptable B contents in HAp are lower than 1.59mmol/g-calcined HAp. These results imply that during calcination of HAp, some borate is excluded to form the by-phase xCaO·B 2 O 3 , which is relatively insoluble in water, but some other fractions might be additionally emitted from the amorphous phase to weakly bind the calcined products. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Characterization and Exergy Analysis of Triphenyl Borate

    International Nuclear Information System (INIS)

    Acarali, N. B.

    2015-01-01

    In this study, unlike from the literature, boron oxide, borax decahydrate, boric acid and borax pentahydrate as boron sources were used to synthesize Triphenyl Borate (TPB). The reactions of TPB were carried out by using both phenol and various boron sources in inert water-immiscible organic solvent successfully. On the basis of analyzes (FT-IR, SEM, TGA/DSC) obtained, it was seen that phenol acted as a support to borate structure framework and thermal characterisation of the amorphous solid under determined conditions suggested that usage of different boron sources had effects for glass transition temperature in TPB production. The exergy analysis was performed to the TPB production to determine efficiency. The exergy analysis showed that the highest exergy efficiency was obtained by using boron oxide as a boron source. Consequently, all analyses results showed that TPB was produced successfully. Accordingly, characterization and exergy analysis supported each other. (author)

  1. Strontium borate glass: potential biomaterial for bone regeneration

    OpenAIRE

    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.

    2009-01-01

    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 relea...

  2. Interfacial reactions between titanium and borate glass

    Energy Technology Data Exchange (ETDEWEB)

    Brow, R.K. [Sandia National Labs., Albuquerque, NM (United States); Saha, S.K.; Goldstein, J.I. [Lehigh Univ., Bethlehem, PA (United States). Dept. of Materials Science

    1992-12-31

    Interfacial reactions between melts of several borate glasses and titanium have been investigated by analytical scanning electron microscopy (SEM) and x-ray photoelectron spectroscopy (XPS). A thin titanium boride interfacial layer is detected by XPS after short (30 minutes) thermal treatments. ASEM analyses after longer thermal treatments (8--120 hours) reveal boron-rich interfacial layers and boride precipitates in the Ti side of the interface.

  3. Synthesis and characterization of cadmium doped lead–borate ...

    Indian Academy of Sciences (India)

    Unknown

    structural investigation of boron in these glasses is one of the most attractive points of borate glass formation and related doped systems. In borate glasses, B3+ ions are triangularly coordinated by oxygen atoms and the triangle units are corner bounded in a random configuration (Yawale et al. 2000). PbO and ZnO can ...

  4. Allyl borates: a novel class of polyhomologation initiators

    KAUST Repository

    Wang, De

    2016-12-24

    Allyl borates, a new class of monofunctional polyhomologation initiators, are reported. These monofunctional initiators are less sensitive and more effective towards polymethylene-based architectures. As an example, the synthesis of α-vinyl-ω-hydroxypolymethylenes is given. By designing/synthesizing different allylic borate initiators, and using 1H and 11B NMR spectroscopy, the initiation mechanism was elucidated.

  5. Density of mixed alkali borate glasses: A structural analysis

    International Nuclear Information System (INIS)

    Doweidar, H.; El-Damrawi, G.M.; Moustafa, Y.M.; Ramadan, R.M.

    2005-01-01

    Density of mixed alkali borate glasses has been correlated with the glass structure. It is assumed that in such glasses each alkali oxide associates with a proportional quantity of B 2 O 3 . The number of BO 3 and BO 4 units related to each type of alkali oxide depends on the total concentration of alkali oxide. It is concluded that in mixed alkali borate glasses the volumes of structural units related to an alkali ion are the same as in the corresponding binary alkali borate glass. This reveals that each type of alkali oxide forms its own borate matrix and behaves as if not affected with the presence of the other alkali oxide. Similar conclusions are valid for borate glasses with three types of alkali oxide

  6. Crystal nucleation in lithium borate glass

    Science.gov (United States)

    Smith, Gary L.; Neilson, George F.; Weinberg, Michael C.

    1988-01-01

    Crystal nucleation measurements were made on three lithium borate compositions in the vicinity of Li2O-2Br2O3. All nucleation measurements were performed at 500 C. Certain aspects of the nucleation behavior indicated (tentatively) that it proceeded by a homogeneous mechanism. The steady state nucleation rate was observed to have the largest value when the Li2O concentration was slightly in excess of the diborate composition. The change in nucleation rate with composition is controlled by the variation of viscosity as well as the change in free energy with composition. The variation of nucleation rate is explained qualitatively in these terms.

  7. Rare earth separations by selective borate crystallization

    Science.gov (United States)

    Yin, Xuemiao; Wang, Yaxing; Bai, Xiaojing; Wang, Yumin; Chen, Lanhua; Xiao, Chengliang; Diwu, Juan; Du, Shiyu; Chai, Zhifang; Albrecht-Schmitt, Thomas E.; Wang, Shuao

    2017-03-01

    Lanthanides possess similar chemical properties rendering their separation from one another a challenge of fundamental chemical and global importance given their incorporation into many advanced technologies. New separation strategies combining green chemistry with low cost and high efficiency remain highly desirable. We demonstrate that the subtle bonding differences among trivalent lanthanides can be amplified during the crystallization of borates, providing chemical recognition of specific lanthanides that originates from Ln3+ coordination alterations, borate polymerization diversity and soft ligand coordination selectivity. Six distinct phases are obtained under identical reaction conditions across lanthanide series, further leading to an efficient and cost-effective separation strategy via selective crystallization. As proof of concept, Nd/Sm and Nd/Dy are used as binary models to demonstrate solid/aqueous and solid/solid separation processes. Controlling the reaction kinetics gives rise to enhanced separation efficiency of Nd/Sm system and a one-step quantitative separation of Nd/Dy with the aid of selective density-based flotation.

  8. Structure and Properties of Compressed Borate Glasses

    DEFF Research Database (Denmark)

    Smedskjær, Morten Mattrup; Bauer, U.; Behrens, H.

    While the influence of thermal history on the structure and properties of glasses has been thoroughly studied in the past century, the influence of pressure history has received considerably less attention. In this study, we investigate the pressure-induced changes in structure and properties...... in a series of borate glasses. Upon isostatic compression, NMR experiments show that the fraction of tetrahedral boron increases, leading to an overall decrease of the molar volume of the network. We correlate these structural changes with changes in elastic moduli from Brillouin scattering experiments......, hardness and crack formation from nanoindentation experiments, and overshoot in isobaric heat capacity from DSC experiments at ambient pressure. The influence of the initial boron speciation on the degree of changes in structure and properties will also be discussed....

  9. Gakel'-Turov oscillations in iron borate

    International Nuclear Information System (INIS)

    Mitsay, Yu.N.; Skibinsky, K.M.; Strugatsky, M.B.; Korolyuk, A.P.; Tarakanov, V.V.; Khizhnyi, V.I.

    2000-01-01

    Dependence of the amplitude of transverse sound passed through a basal plate of easy-plane weak ferromagnet FeBO 3 on a magnetic field H, parallel to the plate is investigated in experiment at T=77 K. This dependence is of the oscillating form. The phenomenon is caused by magnetic birefringence of transverse sound, being the analog of Cotton-Mouton optical effect. In acoustics this effect is associated with magnetic additions appearing in elastic modules upon transition from a paramagnetic phase to an antiferromagnetic one. However, the theory of magnetoacoustic birefringence for homogeneously magnetized crystals, valid for MnCO 3 , is unable to explain the experiment for FeBO 3 . A model, taking into account the experimental boundary conditions and inhomogeneous distribution of magnetization in the sample of iron borate is constructed. Calculations based on this model describe the experiment satisfactorily

  10. DVD. Borat - ühiskonna sanitar / Tiit Tuumalu

    Index Scriptorium Estoniae

    Tuumalu, Tiit, 1971-

    2007-01-01

    Lühiarvustus DVDl ilmunud filmile "Borat - kultuurialased õppetunnid Ameerikast abiks suursuguse Kasahstani riigi ülesehitamisel" : režissöör Larry Charles, peaosas Sacha Baron Cohen : Ameerika Ühendriigid 2006

  11. Borat tungib psüühesse / Rain Tolk

    Index Scriptorium Estoniae

    Tolk, Rain, 1977-

    2006-01-01

    Briti koomik Sacha Baron Cohen ja tema loodud peategelasega film "Borat - kultuurialased õppetunnid Ameerikast abiks suursuguse Kasahstani riigi ülesehitamisel", režissöör Larry Charles : Ameerika Ühendriigid 2006

  12. Interaction of natural borates with potassium hydroxide solution

    International Nuclear Information System (INIS)

    Azarova, L.A.; Vinogradov, E.E.; Kudinov, I.B.; Panasyuk, G.P.; Danilov, V.P.

    2000-01-01

    Interaction of natural borates - inyoite, ulexite and hydroboracite MgCa[B 3 O 4 (OH) 3 ] 2 ·3H 2 O with KOH solution is studied at 50 Deg C by the methods of chemical, x- ray phase, differential thermal analyses and IR spectroscopy. IR spectra points out on island character of forming borates and confirms the data of x-ray phase and chemical analyses about presence of asharite and calcium hydrous borate in resulting products. Hydroboracite (chain structure) under the action of potassium hydroxide passes into borates of magnesium and calcium with island structure and in this case boron transforms partially into liquid phase. When potassium hydroxide interacts with inyoite and ulexite calcium hydroxide and roentgenoamorphous boron-containing product precipitate [ru

  13. Angiogenic effects of borate glass microfibers in a rodent model.

    Science.gov (United States)

    Lin, Yinan; Brown, Roger F; Jung, Steven B; Day, Delbert E

    2014-12-01

    The primary objective of this research was to evaluate the use of bioactive borate-based glass microfibers for angiogenesis in soft tissue repair applications. The effect of these fibers on growth of capillaries and small blood vessels was compared to that of 45S5 silica glass microfibers and sham implant controls. Compressed mats of three types of glass microfibers were implanted subcutaneously in rats and tissues surrounding the implant sites histologically evaluated 2-4 weeks post surgery. Bioactive borate glass 13-93B3 supplemented with 0.4 wt % copper promoted extensive angiogenesis as compared to silica glass microfibers and sham control tissues. The angiogenic responses suggest the copper-containing 13-93B3 microfibers may be effective for treating chronic soft tissue wounds. A second objective was to assess the possible systemic cytotoxicity of dissolved borate ions and other materials released from implanted borate glass microfibers. Cytotoxicity was assessed via histological evaluation of kidney tissue collected from animals 4 weeks after subcutaneously implanting high amounts of the borate glass microfibers. The evaluation of the kidney tissue from these animals showed no evidence of chronic histopathological changes in the kidney. The overall results indicate the borate glass microfibers are safe and effective for soft tissue applications. © 2014 Wiley Periodicals, Inc.

  14. 21 CFR 872.3400 - Karaya and sodium borate with or without acacia denture adhesive.

    Science.gov (United States)

    2010-04-01

    ... denture adhesive. 872.3400 Section 872.3400 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... and sodium borate with or without acacia denture adhesive. (a) Identification. A karaya and sodium borate with or without acacia denture adhesive is a device composed of karaya and sodium borate with or...

  15. Low-energy vibrational dynamics of cesium borate glasses.

    Science.gov (United States)

    Crupi, C; D'Angelo, G; Vasi, C

    2012-06-07

    Low-temperature specific heat and inelastic light scattering experiments have been performed on a series of cesium borate glasses and on a cesium borate crystal. Raman measurements on the crystalline sample have revealed the existence of cesium rattling modes in the same frequency region where glasses exhibit the boson peak (BP). These localized modes are supposed to overlap with the BP in cesium borate glasses affecting its magnitude. Their influence on the low frequency vibrational dynamics in glassy samples has been considered, and their contribution to the specific heat has been estimated. Evidence for a relation between the changes of the BP induced by the increased amount of metallic oxide and the variations of the elastic medium has been provided.

  16. Crystallo-chemistry of boric anhydride and of anhydrous borates

    International Nuclear Information System (INIS)

    Bernardin, Jacques

    1968-01-01

    After an overview of various aspects related to the atomic structure of boron and of its three-bind and four-bind compounds, this report briefly presents the different forms of boric anhydride (in solid, liquid, glassy and gaseous state), presents and comments the structure of these different forms, and addresses the molten boric anhydride which is used as oxide solvent. The next part addresses the structure of anhydrous borates. It presents some generalities on their structure, and describes examples of known structures: dimers, trimers, polymers with a degree higher than three like calcium metaborate, caesium tri-borate, lithium tetraborate, or potassium pentaborate

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

    DEFF Research Database (Denmark)

    Bache, Morten; Guo, Hairun; Zhou, Binbin

    2013-01-01

    A popular crystal for ultrafast cascading experiments is beta-barium-borate (β-BaB2O4, BBO). It has a decent quadratic nonlinear coefficient, and because the crystal is anisotropie it can be birefringence phase-matched for type I (oo → e) second-harmonic generation (SHG). For femtosecond experime......A popular crystal for ultrafast cascading experiments is beta-barium-borate (β-BaB2O4, BBO). It has a decent quadratic nonlinear coefficient, and because the crystal is anisotropie it can be birefringence phase-matched for type I (oo → e) second-harmonic generation (SHG). For femtosecond...

  18. Effect of Magnesium Borates on the Fire-Retarding Properties of Zinc Borates

    Directory of Open Access Journals (Sweden)

    Azmi Seyhun Kipcak

    2014-01-01

    Full Text Available Magnesium borate (MB is a technical ceramic exhibiting high heat resistance, corrosion resistance, great mechanical strength, great insulation properties, lightweightness, high strength, and a high coefficient of elasticity. Zinc borate (ZB can be used as a multifunctional synergistic additive in addition to flame retardant additives in polymers. In this study, the raw materials of zinc oxide (ZnO, magnesium oxide (MgO, and boric acid (H3BO3 were used in the mole ratio of 1 : 1 : 9, which was obtained from preexperiments. Using the starting materials, hydrothermal synthesis was applied, and characterisation of the products was performed using X-Ray diffraction (XRD and Fourier transform infrared (FT-IR and Raman spectroscopies. The forms of Zn3B6O12·3.5H2O, MgO(B2O33·7(H2O, and Mg2(B6O7(OH62·9(H2O were synthesised successfully. Moreover, the surface morphology was investigated using scanning electron microscopy (SEM, and the B2O3 content was determined. In addition, the reaction yields were calculated. The results of the B2O3 content analysis were in compliance with the literature values. Examination of the SEM images indicated that the obtained nanoscale minerals had a reaction efficiency ranging between 63–74% for MB and 87–98% for ZB. Finally, the fire-retarding properties of the synthesised pure MBs, pure ZBs, and mixtures of MB and ZB were determined using differential thermal analysis and thermal gravimetry (DTA-TG and differential scanning calorimetry (DSC.

  19. Effect of borate concentration on solidification of radioactive wastes by different cements

    International Nuclear Information System (INIS)

    Sun Qina; Li Junfeng; Wang Jianlong

    2011-01-01

    Highlights: → The effect of borate on cementation of radioactive borate evaporator concentrates by sulfoaluminate cement (SAC) and Portland cement (PC) was compared. → The X-ray diffraction (XRD) revealed that borate did not interfere with the formation of main hydration products of SAC and PC. → Borate, in the form of B(OH) 4- , incorporated in ettringite as solid solution phase. - Abstract: To investigate the effect of borate on the cementation of radioactive evaporator concentrates, and to provide more data for solidification formula optimization, the simulated borate evaporator concentrates with different borate concentrations (as B) and Na/B ratio (molar ratio) were solidified by sulfoaluminate cement (SAC) and Portland cement (PC), with addition of Ca(OH) 2 , zeolite and accelerator or water reducer. The hydration products of solidified matrices were characterized by X-ray diffraction (XRD). The experimental results showed that borate retarded the cement setting for both SAC and PC formulas, and the final setting time prolonged with decrease of Na/B ratio. Borate could enhance the fluidity of the cement mixture. The 28 d compressive strengths of the solidified matrices for both SAC and PC formulas decreased with increase of borate concentration. The XRD patterns suggested that, in the matrices maintained for 28 d, borate did not interfere with the formation of main hydration products of SAC and PC. Borate, in the form of B(OH) 4- , incorporated in ettringite (3CaO.Al 2 O 3 .3CaSO 4 .32H 2 O) as solid solution phase. The formula of SAC and PC developed in this study was effective for cementation of the simulated borate evaporator concentrates. However further optimization was required to reduce retarding effect of higher borate concentrations and to extend the practical feasibility for actual evaporator concentrates.

  20. Infrared spectra of zinc doped lead borate glasses

    Indian Academy of Sciences (India)

    Unknown

    Abstract. The infrared spectra of zinc-doped lead borate glasses (10–30 mol% ZnO) were measured over a continuous spectral range (400–4000 cm–1) in an attempt to study their structure systematically. No boroxol ring formation was observed in the structure of these glasses. The formation of Zn in tetrahedral ...

  1. Infrared spectra of zinc doped lead borate glasses

    Indian Academy of Sciences (India)

    Unknown

    subject of numerous infrared studies due to their structural peculiarities (Wang and Angell 1976; Kamitsos and. Karakassides 1989). Recently, the study of oxide glasses has received considerable attention due to their structural peculiarities. In borate glasses, B2O3 is a basic glass former because of its higher bond strength ...

  2. Linear and nonlinear optical properties of borate crystals as ...

    Indian Academy of Sciences (India)

    Unknown

    contain usually 30–100 atoms per unit cell and bears low symmetry, from the first principles with an accuracy accep- table for materials development/design. With above important series of borate crystals as examples, it was shown how the computational approach, which was car- ried out at present by LAPW and CASTEP ...

  3. Glass-Forming Ability of Soda Lime Borate Liquids

    DEFF Research Database (Denmark)

    Zheng, Qiuju; Mauro, J.C.; Smedskjær, Morten Mattrup

    2012-01-01

    We investigate the composition dependence of glass-forming ability (GFA) of a series of iron-containing soda lime borate liquids by substituting Na2O for B2O3. We have characterized GFA by measuring the glass stability against crystallization using a differential scanning calorimeter (DSC...

  4. Optical properties of alkaline earth borate glasses | Rao ...

    African Journals Online (AJOL)

    Borate glasses containing fixed concentrations of heavy metal oxides (MO= ZnO, PbO, TeO2, Bi2O3) and alkaline earth oxides (R= Mg, Ca, Sr, Ba) are prepared by melt quenching technique. The optical band gap values are estimated from the optical absorption spectra using absorption spectrum fitting (ASF) method.

  5. CADMIUM-RARE EARTH BORATE GLASS AS REACTOR CONTROL MATERIAL

    Science.gov (United States)

    Ploetz, G.L.; Ray, W.E.

    1958-11-01

    A reactor control rod fabricated from a cadmiumrare earth-borate glass is presented. The rare earth component of this glass is selected from among those rare earths having large neutron capture cross sections, such as samarium, gadolinium or europium. Partlcles of this glass are then dispersed in a metal matrix by standard powder metallurgy techniques.

  6. Ultrasonic investigations of some bismuth borate glasses doped with ...

    Indian Academy of Sciences (India)

    The results revealed that the density increased with increasing Bi2O3 content, which was attributed to the increase in the compactness and packing of the glass network. The ultrasonic data were analysed in terms of creation of new bonds of Bi2O3 attached to the structural units of the borate network. The new bonds ...

  7. Thermoluminescence response of rare earth activated zinc lithium borate glass

    Science.gov (United States)

    Saidu, A.; Wagiran, H.; Saeed, M. A.; Obayes, H. K.; Bala, A.; Usman, F.

    2018-03-01

    New glasses of zinc lithium borate doped with terbium oxide were synthesized by high temperature solid-state reaction. The amorphous nature of the glasses was confirmed using x-ray diffraction analysis (XRD). Thermoluminescence (TL) response of pure zinc lithium borate (ZLB) and zinc lithium borate doped with terbium (ZLB: Tb) exposed to gamma radiation was measured and compared. There is significant enhancement in the TL yields of ZLB: Tb compared to that of pure ZLB. Effect of varying concentration of dopant (Tb4O7) on the TL response of zinc lithium borate was investigated. 0.3 mol% concentration of Tb exhibited strongest TL intensity. Thermoluminescence curve of the phosphor consist of single isolated peak. The TL response of the new materials to the exposed radiation is linear within 0.5-100 Gy range of dose with sublinearity at the lower region of the curve. High sensitivity was exhibited by the new amorphous materials. Reproducibility, thermal fading and energy response of the proposed TLD were investigated and shows remarkable result that made the phosphor suitable for radiation dosimetry.

  8. 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.

  9. Silver lead borate glasses doped with europium ions for phosphors ...

    Indian Academy of Sciences (India)

    2017-07-25

    Jul 25, 2017 ... Glasses containing silver have been technologically interesting materials for solid- state batteries and electrochemical devices because of their valuable optical properties and high value of ionic con- ductivity [5]. Lead borate glasses are a research interest, owing to their structural peculiarities. The addition ...

  10. Thermal, optical and spectroscopic characterizations of borate laser crystals

    Czech Academy of Sciences Publication Activity Database

    Chavoutier, M.; Jubera, V.; Veber, P.; Velazquez, M.; Viraphong, O.; Hejtmánek, Jiří; Decourt, R.; Debray, J.; Menaert, B.; Segonds, P.; Adamietz, F.; Rodriguez, V.; Manek-Hönninger, I.; Fargues, A.; Descamps, D.; Garcia, A.

    2011-01-01

    Roč. 184, č. 2 (2011), s. 441-446 ISSN 0022-4596 Institutional research plan: CEZ:AV0Z10100521 Keywords : borate crystals * thermal properties * refractive index * luminescence * ytterbium * laser materials Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.159, year: 2011

  11. Overview of ultraviolet and infrared spectroscopic properties of Yb3+ doped borate and oxy-borates compounds

    International Nuclear Information System (INIS)

    Sablayrolles, J.

    2006-12-01

    The trivalent ytterbium ion can give rise to two emissions with different spectroscopic properties: the first one, with a short lifetime, in the ultraviolet (charge transfer emission) is used in detectors such as scintillators, and the other one, with a long lifetime, in the infrared (4f-4f emission) for laser applications. The strong link between material structure and properties is illustrated through ytterbium luminescence study, in the ultraviolet and infrared, inserted in the borate Li 6 Y(BO 3 ) 3 and two oxy-borates: LiY 6 O 5 (BO 3 ) 3 and Y 17,33 B 8 O 38 . For the first time an ytterbium charge transfer emission in oxy-borates has been observed. The calculation of the single configurational coordinate diagram, as well as the thermal quenching, has been conducted under a fundamental approach on the ytterbium - oxygen bond. The study of the ytterbium infrared spectroscopy in these compounds has been realised and an energy level attribution is proposed in the particular case of the borate Li 6 Y(BO 3 ) 3 : Yb 3+ . An original approach is introduced with the study of the charge transfer states for the three compounds by looking at the infrared emission. The first laser performances in three operating modes (continuous wave, Q-switch and mode locking) of a Li 6 Y(BO 3 ) 3 : Yb 3+ crystal are reported. (author)

  12. Neutron shielding properties of a borated high-density glass

    Directory of Open Access Journals (Sweden)

    Saeed Aly Abdallah

    2017-01-01

    Full Text Available The neutron shielding properties of a borated high density glass system was characterized experimentally. The total removal macroscopic cross-section of fast neutrons, slow neutrons as well as the linear attenuation coefficient of total gamma rays, primary in addition to secondary, were measured experimentally under good geometric condition to characterize the attenuation properties of (75-x B2O3-1Li2O-5MgO-5ZnO-14Na2O-xBaO glassy system. Slabs of different thicknesses from the investigated glass system were exposed to a collimated beam of neutrons emitted from 252Cf and 241Am-Be neutron sources in order to measure the attenuation properties of fast and slow neutrons as well as total gamma rays. Results confirmed that barium borate glass was suitable for practical use in the field of radiation shielding.

  13. Visible luminescence of dysprosium ions in oxyhalide lead borate glasses.

    Science.gov (United States)

    Pisarska, Joanna; Żur, Lidia; Pisarski, Wojciech A

    2011-08-15

    Visible luminescence of Dy(3+) ions in oxyhalide lead borate glasses was examined. Luminescence spectra show two intense bands at 480 nm and 573 nm due to (4)F(9/2)→(6)H(15/2) (blue) and (4)F(9/2)→(6)H(13/2) (yellow) transitions of Dy(3+). Luminescence decays from (4)F(9/2) state and yellow-to-blue luminescence intensity ratios (Y/B) were analysed with PbX(2) (X=F, Cl) content. An introduction of PbX(2) to the borate glass results in the increasing of (4)F(9/2) lifetime and the decreasing of yellow-to-blue luminescence intensity ratio, which is due to reduction of covalency between Dy(3+) and O(2-)/X(-) ions. Copyright © 2010 Elsevier B.V. All rights reserved.

  14. Synthesis and evaluation of borates derived from boric acid and diols for the protection of wood against fungal decay and thermal degradation

    Science.gov (United States)

    George C. Chen

    2004-01-01

    N,N-dimethyl amino carbinol catechol borate(1). N,N-dimethyl amino carbinol-4-methyl catechol borate(2), N,N-dimethyl amino carbinol-4-t- butyl catechol borate(3). N,N-dimethyl amino carbinol-2,3-naphthyl borate 4) were synthesized by refluxing boric acid and diol in DMF(N,N-dimethyl formamide). The borates were characterized by NMR. Wood impregnated with borate 1,2 or...

  15. DID WE IGNORE THE SOCIAL COMMENTARY? RESPONDING TO BORAT ON YOUTUBE

    Directory of Open Access Journals (Sweden)

    Mārtiņš Kaprāns

    2011-11-01

    Full Text Available Ever since the fictitious Kazakh journalist Borat Sagdiyev became an icon of contemporary popular culture, many questions have arisen about the reception of Borat by the general public. Namely, how have common people created a shared representation of Borat? And how is this complicated character and comedic manner undertaken by Sacha Baron Cohen being deciphered? These questions are crucial for understanding the challenges and constraints of social satire that exploits ethnically and stylistically sophisticated identity. To address these questions, which surely could be asked about other international media products as well, this article deals with the reception of Borat the character on YouTube. In particular, the viewers' reaction to the YouTube video titled "The Best of Borat" is analysed. This video has been viewed more than seven million times and commented on more than seven thousand times. The conceptual framework of this analysis is derived from the theory of social representations postulated by Serge Moscovici. In line with this theory two main dimensions - anchoring and objectification - are explored in order to understand how shared or divergent knowledge of Borat is created. Thus the basic socio-cognitive processes behind Borat are revealed. The results suggest that anchoring of Borat is embedded in national identification discourse, whereas objectification differentiates people according to their sense of humour. Likewise, some implications of Borat's reception for participatory culture and civic engagement are outlined.

  16. Elastic Behavior of Borate Glasses Containing Lead and Bismuth Oxides

    Directory of Open Access Journals (Sweden)

    Mehrdad Khanisanij

    2014-01-01

    Full Text Available PbO and Bi2O3 binary borate glasses with different compositions, (MOX(B2O31−X (M = Pb, Bi, have been characterized and ultrasonic velocity as well as density is taken into account. In addition, the results have been compared with those of Ag, K, and Li oxide borate glasses from others. The ultrasonic velocities (both longitudinal and transverse and density for (PbOX(B2O31−X and (Bi2O3X(B2O31−X have been measured accurately and elastic moduli as well as hardness and Poisson’s ratio was determined. It has been demonstrated that density and ultrasonic velocities are enhanced by increasing PbO and Bi2O3 molar fraction with different values for each borate glass composition. However, the enhancement of ultrasonic velocities did not carry on continuously and after reaching a maximum point, they fell down dramatically. Both PbO and Bi2O3 showed almost similar glass improvement in case of density, ultrasonic velocity, and elastic moduli.

  17. Impact of vanadium ions in barium borate glass.

    Science.gov (United States)

    Abdelghany, A M; Hammad, Ahmed H

    2015-02-25

    Combined optical and infrared spectral measurements of prepared barium borate glasses containing different concentrations of V2O5 were carried out. Vanadium containing glasses exhibit extended UV-visible (UV/Vis.) bands when compared with base binary borate glass. UV/Vis. spectrum shows the presence of an unsymmetrical strong UV broad band centered at 214 nm attributed to the presence of unavoidable trace iron impurities within the raw materials used for the preparation of such glass. The calculated direct and indirect optical band gaps are found to decrease with increasing the vanadium content (2.9:137 for indirect and 3.99:2.01 for direct transition). This change was discussed in terms of structural changes in the glass network. Infrared absorption spectra of the glasses reveal the appearance of both triangular and tetrahedral borate units. Electron spin resonance analyses indicate the presence of unpaired species in sufficient quantity to be identified and to confirm the spectral data. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Fragility, anharmonicity and anelasticity of silver borate glasses

    International Nuclear Information System (INIS)

    Carini, Giovanni; Carini, Giuseppe; D'Angelo, Giovanna; Tripodo, Gaspare; Bartolotta, Antonio; Marco, Gaetano Di

    2006-01-01

    The fragility and the anharmonicity of (Ag 2 O) x (B 2 O 3 ) 1-x borate glasses have been quantified by measuring the change in the specific heat capacity at the glass transition temperature T g and the room-temperature thermodynamic Grueneisen parameter. Increasing the silver oxide content above X = 0.10 leads to an increase of both the parameters, showing that a growing fragility of a glass-forming liquid is predictive of an increasing overall anharmonicity of its glassy state. The attenuation and velocity of ultrasonic waves of frequencies in the range of 10-70 MHz have also been measured in silver borate glasses as a function of temperature between 1.5 and 300 K. The experimental data reveal anelastic behaviours which are governed by (i) quantum-mechanical tunnelling below 20 K (ii) thermally activated relaxations between 20 and 200 K and (iii) vibrational anharmonicity at even higher temperatures. Evaluation of tunnelling (C) and relaxation (C * ) strengths shows that C is independent of the structural changes affecting the borate network with increasing metal oxide content and is at least one order of magnitude smaller than C * . The latter observation implies that only a small fraction of the locally mobile defects are subjected to tunnelling motions

  19. Preparation and Characterization of the Structural, Optical, Spectroscopic and Electrical Properties of Pr2O5 doped Borate Glass

    OpenAIRE

    Vasumathy, Deepa Ananthanarayanan; Murugasen, Priya; Sagadevan, Suresh

    2016-01-01

    Abstract We have successfully synthesized Pr2O5 doped borate glasses by conventional rapid melt quench method. The XRD pattern indicates the amorphous nature of Pr2O5 doped borate glass. An optical property of prepared borate glass was studied using the Photoluminescence spectrum. Determination and differentiation of the various vibrational modes were done using FTIR spectroscopy studies. Raman spectroscopy of Pr2O5 doped borate glass was also carried out. Thermal analyses of the glasses were...

  20. Laboratory evaluation of borate:amine:copper derivatives In wood for fungal decay protection

    Science.gov (United States)

    George Chen

    2011-01-01

    This study aimed to evaluate borate:amine:copper derivatives in wood for fungal decay protection as well as the permanence of copper and boron in wood. Each of four derivatives of borate:amine:copper prevented fungal decay in wood. Disodium tetraborate decahydrate (borax):amine:copper derivatives with 0.61-0.63% retention after water leaching prevented decay by...

  1. Effective binding of perhalogenated closo-borates to serum albumins revealed by spectroscopic and ITC studies

    Science.gov (United States)

    Kuperman, Marina V.; Losytskyy, Mykhaylo Yu.; Bykov, Alexander Yu.; Yarmoluk, Sergiy M.; Zhizhin, Konstantin Yu.; Kuznetsov, Nikolay T.; Varzatskii, Oleg A.; Gumienna-Kontecka, Elzbieta; Kovalska, Vladyslava B.

    2017-08-01

    The interactions of boron cluster compounds closo-borates with biomolecules are widely studied due to their efficiency as agents for boron neutron capture therapy of cancer. In present work the binding abilities of anionic halogen closo-borates [B10Hal10]2- (Hal = Cl, Br, I) and [B12Hal12]2- (Hal = Cl, I) towards bovine and human serum albumins were investigated by spectroscopic and isothermal titration calorimetry (ITC) methods. The protein fluorescence quenching method and ITC studies confirmed the complex formation. The degree of protein fluorescence quenching increased from chlorine to iodine boron derivatives that is attributed to external heavy atom effect. The ITC data point on the existence in the protein structure of two types of binding sites: with higher and lower affinity to closo-borates. Albumin-closo-borate complex binding ratio, n (4-5 anions per protein molecule) is higher than for the parent hydrogen closo-borates (2 anions per protein molecule). Binding constants estimated by fluorescent and ITC methods indicate higher affinity of halogen closo-borates to albumins (K in the range of 104-106 M-1) comparing to that of the hydrogen closo-borate (K about 103 M-1). Due to their high affinity and high binding ratio to albumins halogen closo-borates are proposed for further studies as agents for boron neutron capture therapy.

  2. Recent advances in rare earth doped alkali-alkaline earth borates for solid state lighting applications

    Science.gov (United States)

    Verma, Shefali; Verma, Kartikey; Kumar, Deepak; Chaudhary, Babulal; Som, Sudipta; Sharma, Vishal; Kumar, Vijay; Swart, Hendrik C.

    2018-04-01

    As a novel class of inorganic phosphor, the alkali-alkaline earth borate phosphors have gained huge attention due to their charming applications in solid-state lighting (SSL) and display devices. The current research drive shows that phosphors based on the alkali-alkaline earth borates have transformed the science and technology due to their high transparency over a broad spectral range, their flexibility in structure and durability for mechanical and high-laser applications. Recent advances in various aspects of rare-earth (RE) doped borate based phosphors and their utilizations in SSL and light emitting diodes are summarized in this review article. Moreover, the present status and upcoming scenario of RE-doped borate phosphors were reviewed in general along with the proper credential from the existing literature. It is believed that this review is a sole compilation of crucial information about the RE-doped borate phosphors in a single platform.

  3. Neutron diffraction studies of rare-earth doped borate glasses

    International Nuclear Information System (INIS)

    Vaz, W.A.; Desa, J.A.E.; Krishna, P.S.R.; Shinde, A.B.

    2013-01-01

    Rare-earth ions included in glassy host networks have been studied as prototype systems for nuclear waste management. They are known to exhibit well defined absorptions in the visible region. Optical studies of glasses doped with two different rare-earth ions have been shown to display absorption spectra that are linear combinations of the component rare-earths appropriately weighted by their relative proportions in the glass. Investigations of local structure by diffraction methods may lead to an understanding of the origin of such rare-earth ion interactions. A set of borate glasses have been prepared in which Nd and Pr ions were included in the relative proportions of 1:3 and 3:1 for the two ions. Alumina was added (5 mole%) for ease of preparation and the borate component was 75%. The glasses were quenched in air at room temperature. The host glass was prepared from 11 B boric acid for the neutron diffraction measurements. The data presented here were from X-ray diffraction (CuK α Rigaku D-MAX/B rotating anode) and neutron diffraction using the High Q diffractometer at Dhruva Reactor, B.A.R.C., For both types of measurement, the glasses were crushed to fine powders. The neutron data were collected with the powders in 6 mm diameter, 5 cm high vanadium cans. The structure factors of both glasses and that for the undoped borate glass from the neutron diffraction data are shown. The total correlation functions T(r) are displayed. The presence of the R-O correlations may be observed at about 3.2 Å. Separations of these correlations from both X-ray and neutron data will be presented. (author)

  4. SYNTHESIS OF ALUMINIUM BORATE WHISKERS THROUGH WET MOLTEN SALT METHOD

    Directory of Open Access Journals (Sweden)

    Xue Zhang

    2017-12-01

    Full Text Available Aluminium borate (Al₄B₂O₉ whiskers were successfully synthesized by the wet molten salt method at 800 oC through control the aluminum/boron atomic ratio and synthesis temperature. The as-received Al₄B₂O₉ whiskers were characterized by scanning electron microscopy (SEM, X-ray diffraction (XRD and thermal analysis. A solution-liquid-solid (SLS mechanism was proposed for the growth mechanism of the whiskers on the basis of the experimental phenomena and the TG-DSC data of the mixed raw materials.

  5. Coordination chemistry of poly(thioether)borate ligands

    Science.gov (United States)

    Riordan, Charles G.

    2010-01-01

    This review traces the development and application of the tris(thioether)borate ligands, tripodal ligands with highly polarizable thioether donors. Areas of emphasis include the basic coordination chemistry of the mid-to-late first row transition metals (Fe, Ni, Co, Cu), and the role of the thioether substituent in directing complex formation, the modeling of zinc thiolate protein active sites, high-spin organo-iron and organo-cobalt chemistry, the preparation of monovalent complexes of Fe, Co and Ni, and dioxygen and sulfur activation by monovalent nickel complexes. PMID:20607091

  6. Cell adhesion to borate glasses by colloidal probe microscopy.

    Science.gov (United States)

    Wiederhorn, Sheldon M; Chae, Young-Hun; Simon, Carl G; Cahn, Jackson; Deng, Yan; Day, Delbert

    2011-05-01

    The adhesion of osteoblast-like cells to silicate and borate glasses was measured in cell growth medium using colloidal probe microscopy. The probes consisted of silicate and borate glass spheres, 25-50 μm in diameter, attached to atomic force microscope cantilevers. Variables of the study included glass composition and time of contact of the cell to the glasses. Increasing the time of contact from 15 to 900 s increased the force of adhesion. The data could be plotted linearly on a log-log plot of adhesive force versus time. Of the seven glasses tested, five had slopes close to 0.5, suggesting a square root dependence of the adhesive force on the contact time. Such behavior can be interpreted as a diffusion limited process occurring during the early stages of cell attachment. We suggest that the rate limiting step in the adhesion process is the diffusion of integrins resident in the cell membrane to the area of cell attachment. Data presented in this paper support the hypothesis of Hench et al. that strong adhesion depends on the formation of a calcium phosphate reaction layer on the surfaces of the glass. Glasses that did not form a calcium phosphate layer exhibited a weaker adhesive force relative to those glasses that did form a calcium phosphate layer. Published by Elsevier Ltd.

  7. Preparation and properties of porous microspheres made from borate glass.

    Science.gov (United States)

    Conzone, Samuel D; Day, Delbert E

    2009-02-01

    Dysprosium lithium-borate glass microspheres and particles, ranging from 45 to 150 microm in diameter, were reacted with a 0.25 M phosphate solution at 37 degrees C, whose pH was either 3 or 8.8. The glass reacted nonuniformly and was converted into a porous, amorphous, hydrated, dysprosium phosphate reaction product. The amorphous product had the same volume and shape (pseudomorphic) as the unreacted glass, and could be dried without cracking. After heating at 300 degrees C for 1 h, the amorphous reaction product had a specific surface area of approximately 200 m(2)/g, a pore size of approximately 30 nm, and nominal crushing strength of approximately 10 MPa. When the reaction product was heated to 600 degrees C for 15 min, the specific surface area decreased to approximately 90 m(2)/g and the nominal crushing strength increased to 35 MPa. Heating above 615 degrees C converted the amorphous dysprosium phosphate product into crystalline DyPO(4), which contained open porosity until heated above 800 degrees C for 15 min. Highly porous materials of different chemical composition can be prepared by chemically reacting a borate-based glass with an aqueous solution at low-temperature (<100 degrees C). These highly porous materials are easy to process, and are considered candidates for controlled drug delivery, catalysis, chromatographic separation, filtration, and as bioactive materials.

  8. Transition and post-transition metal ions in borate glasses: Borate ligand speciation, cluster formation, and their effect on glass transition and mechanical properties.

    Science.gov (United States)

    Möncke, D; Kamitsos, E I; Palles, D; Limbach, R; Winterstein-Beckmann, A; Honma, T; Yao, Z; Rouxel, T; Wondraczek, L

    2016-09-28

    A series of transition and post-transition metal ion (Mn, Cu, Zn, Pb, Bi) binary borate glasses was studied with special consideration of the cations impact on the borate structure, the cations cross-linking capacity, and more generally, structure-property correlations. Infrared (IR) and Raman spectroscopies were used for the structural characterization. These complementary techniques are sensitive to the short-range order as in the differentiation of tetrahedral and trigonal borate units or regarding the number of non-bridging oxygen ions per unit. Moreover, vibrational spectroscopy is also sensitive to the intermediate-range order and to the presence of superstructural units, such as rings and chains, or the combination of rings. In order to clarify band assignments for the various borate entities, examples are given from pure vitreous B 2 O 3 to meta-, pyro-, ortho-, and even overmodified borate glass compositions. For binary metaborate glasses, the impact of the modifier cation on the borate speciation is shown. High field strength cations such as Zn 2+ enhance the disproportionation of metaborate to polyborate and pyroborate units. Pb 2+ and Bi 3+ induce cluster formation, resulting in PbO n - and BiO n -pseudophases. Both lead and bismuth borate glasses show also a tendency to stabilize very large superstructural units in the form of diborate polyanions. Far-IR spectra reflect on the bonding states of modifier cations in glasses. The frequency of the measured cation-site vibration band was used to obtain the average force constant for the metal-oxygen bonding, F M-O . A linear correlation between glass transition temperature (T g ) and F M-O was shown for the metaborate glass series. The mechanical properties of the glasses also correlate with the force constant F M-O , though for cations of similar force constant the fraction of tetrahedral borate units (N 4 ) strongly affects the thermal and mechanical properties. For paramagnetic Cu- and Mn-borate glasses

  9. Elevated temperature tensile properties of borated 304 stainless steel

    International Nuclear Information System (INIS)

    Stephens, J.J.; Sorenson, K.B.; McConnell, P.

    1993-01-01

    This paper presents a comparison of the tensile properties of Powder Metallurgy (PM) 'Grade A' material with that of the conventional IM 'Grade B' material for two selected Types (i.e., boron contents) as defined by the ASTM A887 specification: Types 304B5 and 304B7. Tensile properties have been generated for these materials at temperatures ranging from room temperature to 400degC (752degF). The data at higher temperatures are required for ASME Code Case purposes, since the use temperature of a basket under 'worst case' cask conditions may be as high as 343degC (650degF), due to self-heating by the activated fuel elements. We will also discuss the current status of efforts aimed at obtaining an ASME Boiler and Pressure Vessel Code Case for selected grades of borated stainless steel covered by the ASTM A887 specification. (J.P.N.)

  10. Evaluation of lithium borate as a 7000-R dosimeter

    International Nuclear Information System (INIS)

    Holm, D.M.; Payne, R.J.

    1975-04-01

    The Harshaw Model 2271 TL Detector/Dosimeter system with lithium borate dosimeters was evaluated as a 7000-R dosimetry system. One hundred dosimeter cards having two dosimeters per card were irradiated up to ninety-eight times with x rays from a 250-keV (electron energy) GE x-ray machine. A twofold change in calibration was observed during the course of 98 irradiation cycles and a decrease in light output versus time lag between irradiation and reading was observed. The first card ''failed'' on the 36th cycle and only two cards survived to the 98th cycle. All of the failures were due to damage of the Teflon packaging, causing the dosimeters to hang up in the readout or to move in their card. This system could be used for screwworm fly dosimetry but is not considered ideal. (U.S.)

  11. Neutron measurements in borated water for PWR fuel inspections

    International Nuclear Information System (INIS)

    Rinard, P.M.

    1984-07-01

    A fork detector has been developed for use in the international effort to safeguard irradiated fuel assemblies. To improve interpretation of data from a fork, the following three facets of the detector's neutron counting response have been examined using a tank of borated water and a PWR fresh-fuel assembly: (1) The detector's sensitivity to neutrons initiated at different positions within the assembly was measured and this sensitivity can be used to generate total responses to assemblies with uniform or nonuniform irradiation. (2) Using fission chambers with and without cadmium wrappings provided ratios of count rates that can give an independent estimate of the boron concentration in the water. The precision of a boron determination can be estimated from these measurements. (3) The water temperature was raised, causing small but possibly important effects on the count rates. These facets of the fork detector's neutron response were studied at boron concentrations ranging from 0 to about 3500 ppM

  12. The thermal electrical properties of lithium sodium borate gasses

    International Nuclear Information System (INIS)

    Joshi, Anita R.; Bichile, G.K.

    2012-01-01

    Lithium sodium borate glasses with various composition have been prepared by melt quenching method. DSC studies were carried out. The glass transition temperature were found to decrease with alkali content in single alkali system and increase with second alkali content in mixed alkali system. The dc electrical conductivity has been measured as a function of temperature. The activation energy from the slope of the Arrhenius plots is calculated and it depends on the composition. In one set of single alkali glasses activation energies were found to increase with alkali content and in another set a single alkali system a transition from predominantly electronic to ionic conduction has been observed above 0.16 mol fraction of alkali content. The mixed alkali glasses have shown higher activation energies and lower conductivities. (author)

  13. Structural properties of molybdenum-lead-borate glasses.

    Science.gov (United States)

    Rada, M; Rada, S; Pascuta, P; Culea, E

    2010-11-01

    Glasses and glass ceramics in the system xMoO₃·(100 - x)[3B₂O₃·PbO] with 0 ≤ x ≤ 30 mol% have been prepared from melt quenching method and characterized by means of X-ray diffraction, FTIR, UV-VIS and EPR spectroscopy. We have examined and analyzed the effects of systematic molybdenum ions intercalation on lead-borate glasses and glass ceramics with interesting results. The observations present in these mechanisms show the lead ions bonded ionic have a strong affinity towards [BO₃] units containing non-bridging oxygens and [MoO₄]²⁻ molybdate units. The pronounced affinity towards molybdate anions yields the formation of the PbMoO₄ crystalline phase. Then, the excess of oxygen can be supported into the glass network by the formation of [MoO₆] and [Mo₂O₇] structural units. Pb²(+) ions with 6s² configuration show strong absorption in the ultraviolet due to parity allowed s²-sp transition and yield an absorption band centered at about 310 nm. The changes in the features of the absorption bands centered at about 310 nm can be explained as a consequence of the appearance of additional absorption shoulder due to photoinduced color centers in the glass such as the formation of borate-molybdate and lead-molybdate paramagnetic defect centers in the glasses. The concentration of molybdenum ions influences the shape and width of the EPR signals located at g ∼ 1.86, 1.91 and 5.19. The microenvironment of molybdenum ions in glasses is expected to have mainly sixfold coordination. However, there is a possibility of reduction of a part of molybdenum ions from the Mo⁶(+) to the Mo⁵(+) and Mo⁴(+) to the Mo³(+) states. Copyright © 2010 Elsevier B.V. All rights reserved.

  14. Reaction of sodium calcium borate glasses to form hydroxyapatite.

    Science.gov (United States)

    Han, Xue; Day, Delbert E

    2007-09-01

    This study investigated the transformation of two sodium calcium borate glasses to hydroxyapatite (HA). The chemical reaction was between either 1CaO . 2Na(2)O . 6B(2)O(3) or 2CaO . 2Na(2)O . 6B(2)O(3) glass and a 0.25 M phosphate (K(2)HPO(4)) solution at 37, 75 and 200 degrees C. Glass samples in the form of irregular particles (125-180 microm) and microspheres (45-90 and 125-180 microm) were used in order to understand the reaction mechanism. The effect of glass composition (calcium content) on the weight loss rate and reaction temperature on crystal size, crystallinity and grain shape of the reaction products were studied. Carbonated HA was made by dissolving an appropriate amount of carbonate (K(2)CO(3)) in the 0.25 M phosphate solution. X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy were used to characterize the reaction products. The results show that sodium calcium borate glasses can be transformed to HA by reacting with a phosphate solution. It is essentially a process of dissolution of glass and precipitation of HA. The transformation begins from an amorphous state to calcium-deficient HA without changing the size and shape of the original glass sample. Glass with a lower calcium content (1CaO . 2Na(2)O . 6B(2)O(3)), or reacted at an elevated temperature (75 degrees C), has a higher reaction rate. The HA crystal size increases and grain shape changes from spheroidal to cylindrical as temperature increases from 37 to 200 degrees C. Increase in carbonate concentration can also decrease the crystal size and yield a more needle-like grain shape.

  15. "Kasahhi ajakirjanik" Borat : tapvad kultuurierinevused on pööraselt naljakad / Margus Välja

    Index Scriptorium Estoniae

    Välja, Margus, 1958-

    2006-01-01

    Briti koomiku Sacha Baron Coheni loodud peategelasega USA film "Borat - kultuurialased õppetunnid Ameerikast abiks suursuguse Kasahstani riigi ülesehitamisel" : režissöör Larry Charles. Film jooksis ka Haapsalu kultuurikeskuses

  16. Treatment of timber products with gaseous borate esters, Part 1: factors influencing the treatment process

    CSIR Research Space (South Africa)

    Turner, P

    1995-08-01

    Full Text Available Several factors which influence the treatment of timber products with vapour phase preservatives such as borate esters are considered. Gas flow rate through the substrate was found to be a significant factor limiting both preservative penetration...

  17. Barium borate β-BaB2O4 as a material for nonlinear optics

    International Nuclear Information System (INIS)

    Fedorov, Pavel P; Kokh, Aleksandr E; Kononova, Nadezhda G

    2002-01-01

    Data on the structure, polymorphism, phase equilibria, growth techniques, properties and applications of single crystals of the low-temperature modification of barium borate are analysed. The bibliography includes 201 references.

  18. INFLUENCE OF BORATE BUFFERS ON THE ELECTROPHORETIC BEHAVIOR OF HUMIC SUBSTANCES IN CAPILLARY ZONE ELECTROPHORESIS

    Science.gov (United States)

    The influence of tetrahydroxyborate ions on the electrophoretic mobility of humic acids was evaluated by capillary electrophoresis (CE). Depending on the molarity of borate ions in the separation buffer, the humic acids exhibit electropherograms with sharp peaks consistently exte...

  19. Solid-liquid Phase Equilibria of the Aqueous Systems Containing Lithium, Magnesium and Borate Ions

    Science.gov (United States)

    Song, Yun; Zhao, Dong; Du, Xuemin; Wang, Shiqiang; Guo, Yafei; Deng, Tianlong

    2017-12-01

    It is well known that the phase chemistry is of great importance in the fields of chemistry, chemical engineering, and the separation and purification of minerals from brine. To effectively employ the resources containing lithium, magnesium and borate, the study on phase equilibrium is essential to the comprehensive utilization of the Salt Lake resources. In this paper, progresses on phase equilibria of salt-water systems containing lithium, magnesium and borate were presented.

  20. Radiation Shielding Properties Comparison of Pb-Based Silicate, Borate, and Phosphate Glass Matrices

    OpenAIRE

    Ruengsri, Suwimon

    2014-01-01

    Theoretical calculations of mass attenuation coefficients, partial interactions, atomic cross-section, and effective atomic numbers of PbO-based silicate, borate, and phosphate glass systems have been investigated at 662 keV. PbO-based silicate glass has been found with the highest total mass attenuation coefficient and then phosphate and borate glasses, respectively. Compton scattering has been the dominate interaction contributed to the different total attenuation coefficients in each of th...

  1. Spectroscopic and Radiative Properties of Several Nd3+ Ions in Borate Glass System

    OpenAIRE

    Rajagukguk, Juniastel; Djamal, M; Hidayat, R; Suprijadi, Suprijadi; Aminudin, A; Kaewkhao, J

    2016-01-01

    Radiative properties and spectroscopic studies of several Nd3+ doped Borate glass system have been reported. Judd-Ofelt intensity parameter and other parameters like oscillator strength (f), effective bandwidth (Dleff), radiative transition probabilities (AR), stimulated emission cross section (s), branching ratio (bR), radiative lifetime (tR) and experimental lifetime (texp) for the hypersensitive Nd3+ doped Borate Glass are listed and discussed. The variation of W2 values for the different...

  2. Laboratory evaluation of borate/amine/zinc formulations for fungal decay protection

    Science.gov (United States)

    George C. Chen; Rebecca E. Ibach

    2010-01-01

    The goals of this study were to evaluate borate/amine/zinc formulations in wood for fungal decay protection as well as the permanence of zinc and boron in wood. Wood treated with each of four formulations of borate/amine/zinc prevented or decreased fungal degradation after a 12-week AWPA Standard soil-block test. For non-leached specimens, wood treated with borax/amine...

  3. Method of preparing borate glass samples for X-ray spectral analysis

    International Nuclear Information System (INIS)

    Krajickova, M.

    1988-01-01

    The powder mixture of the studied sample is melted with a lithium borate melting agent in platinum vessels. To the molten glass is added crystalline iodine pentoxide which increases surface tension of the glass. The advantage of this procedure is the forming of a compact borate pearl and thereby absolute quantitative removal of the sample from the crucible and vessel. Platinum vessels need not be boiled in acids, which is time and cost saving. (E.S.)

  4. Dosimetric properties of dysprosium doped lithium borate glass irradiated by 6 MV photons

    International Nuclear Information System (INIS)

    Ab Rasid, A.; Wagiran, H.; Hashim, S.; Ibrahim, Z.; Ali, H.

    2015-01-01

    Undoped and dysprosium doped lithium borate glass system with empirical formula (70–x) B 2 O 3 –30 Li 2 O–(x) Dy 2 O 3 (x=0.1, 0.3, 0.5, 0.7, 1.0 mol%) were prepared using the melt-quenching technique. The dosimetric measurements were performed by irradiating the samples to 6 MV photon beam using linear accelerator (LINAC) over a dose range of 0.5–5.0 Gy. The glass series of dysprosium doped lithium borate glass produced the best thermoluminescence (TL) glow curve with the highest intensity peak from sample with 1.0 mol% Dy 2 O 3 concentration. Minimum detectable dose was detected at 2.24 mGy, good linearity of regression coefficient, high reproducibility and high sensitivity compared to the undoped glass are from 1.0 mol% dysprosium doped lithium borate glass. The results indicated that the series of dysprosium doped lithium glasses have a great potential to be considered as a thermoluminescence dosimetry (TLD). - Highlights: • TL response of undoped and dysprosium doped lithium borate glass subjected to 6 MV photons irradiation at low dose range. • TL linear response of dysprosium doped lithium borate glass. • The sensitivity of dysprosium doped lithium borate glass is approximately 93 times higher than undoped glass

  5. Mg- and K-bearing borates and associated evaporites at Eagle Borax spring, Death Valley, California: A spectroscopic exploration

    Science.gov (United States)

    Crowley, J.K.

    1996-01-01

    Efflorescent crusts at the Eagle Borax spring in Death Valley, California, contain an array of rare Mg and K borate minerals, several of which are only known from one or two other localities. The Mg- and/or K-bearing borates include aristarainite, hydroboracite, kaliborite, mcallisterite, pinnoite, rivadavite, and santite. Ulexite and probertite also occur in the area, although their distribution is different from that of the Mg and K borates. Other evaporite minerals in the spring vicinity include halite, thenardite, eugsterite, gypsum-anhydrite, hexahydrite, and bloedite. Whereas the first five of these minerals are found throughout Death Valley, the last two Mg sulfates are more restricted in occurrence and are indicative of Mg-enriched ground water. Mineral associations observed at the Eagle Borax spring, and at many other borate deposits worldwide, can be explained by the chemical fractionation of borate-precipitating waters during the course of evaporative concentration. The Mg sulfate and Mg borate minerals in the Eagle Borax efflorescent crusts point to the fractionation of Ca by the operation of a chemical divide involving Ca carbonate and Na-Ca borate precipitation in the subsurface sediments. At many other borate mining localities, the occurrence of ulexite in both Na borate (borax-kernite) and Ca borate (ulexite-colemanite) deposits similarly reflects ulexite's coprecipitation with Ca carbonate at an early concentration stage. Such ulexite may perhaps be converted to colemanite by later reaction with the coexisting Ca carbonate - the latter providing the additional Ca2+ ions needed for the conversion. Mg and Ca-Mg borates are the expected late-stage concentration products of waters forming ulexite-colemanite deposits and are therefore most likely to occur in the marginal zones or nearby mud facies of ulexite-colemanite orebodies. Under some circumstances, Mg and Ca-Mg borates might provide a useful prospecting guide for ulexite-colemanite deposits

  6. An interaction of the functionalized closo-borates with albumins: The protein fluorescence quenching and calorimetry study

    International Nuclear Information System (INIS)

    Losytskyy, Mykhaylo Yu.; Kovalska, Vladyslava B.; Varzatskii, Oleg A.; Kuperman, Marina V.; Potocki, Slawomir; Gumienna-Kontecka, Elzbieta; Zhdanov, Andrey P.; Yarmoluk, Sergiy M.; Voloshin, Yan Z.; Zhizhin, Konstantin Yu.; Kuznetsov, Nikolai T.; Elskaya, Anna V.

    2016-01-01

    An interaction of the boron clusters closo-borates K 2 [B 10 H 10 ], K 2 [B 12 H 12 ] and their functionalized derivatives with serum proteins human (HSA) and bovine (BSA) albumins and immonoglobulin IgG as well as globular proteins β-lactoglobulin and lysozyme was characterized. The steady state and time resolved protein fluorescence quenching studies point on the binding of the closo-borate arylamine derivatives to serum albumins and discrimination of other proteins. The mechanism of the albumin fluorescence quenching by the closo-borate arylamine derivatives was proposed. The complex formation between albumin and the closo-borate molecules has been confirmed by isothermal titration calorimetry (ITC). The compound (K 2 [B 10 H 10 ]) and its arylamine derivative both interact with HSA, have close values of K a (1.4 and 1.2×10 3 M −1 respectively) and Gibbs energy (−17.9 and −17.5 kJ/mol respectively). However, the arylamine derivative forms complex with the higher guest/host binding ratio (4:1) comparing to the parent closo-borate (2:1). - Highlights: • Complex formation between boron clusters closo-borates and albumins was confirmed. • Functional substituent of closo-borate strongly affects its complex with albumins. • Binding of arylamine closo-borates essentially quench the albumin fluorescence. • Mechanism of tryptophan emission quenching by arylamine closo-borates was proposed.

  7. Ion-conductivity of thin film Li-Borate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Abouzari, M.R.S.

    2007-12-17

    In this thesis, the specific conductivity of ion-sputtered lithium borate thin films is studied. To this end, lithium borate glasses of the composition yLi{sub 2}O.(1-y)B{sub 2}O{sub 3} with y=0.15, 0.20, 0.25, and 0.35 were produced as sputter targets. Films with thicknesses between 7 nm and 700 nm are deposited on silicon substrate between two AlLi electrodes. Conductivity spectra have been taken over a frequency range of 5 Hz to 2 MHz. The measurements were performed at different temperatures between 40 C and 350 C depending on the thickness and the composition of the films. The following results are derived by studying the conductivities of the films: i) The specific dc conductivity of layers with thicknesses larger than 150 nm is independent of their thicknesses; we call these layers 'thick films' and consider their conductivity as the 'base conductivity'. ii) The specific dc conductivity of layers with thicknesses smaller than 150 nm, called 'thin films', depends on the layer thickness. A nontrivial enhancement of the specific dc conductivity about three orders of magnitude for y=0.15, 0.2, and 0.25 is observed. iii) The base conductivity depends on y and at 120 C it varies between 4 x 10{sup -10} {omega}{sup -1}cm{sup -1} and 2.5 x 10{sup -6} {omega}{sup -1}cm{sup -1} when y varies between 0.15 and 0.35, whereas the maximum value of the specific dc conductivity of extremely thin films (with a thickness of some nanometre) seems to be independent of y and equals to the specific dc conductivity of layers with y= 0.35. Furthermore, we found in this work a physical interpretation of the so-called 'Constant Phase Element' (CPE) which is widely used in equivalent circuits for ionic conductors. This element describes correctly the depressed impedance semicircles observed in impedance spectroscopy. So far, this effect is sometimes attributed to the surface roughness. We have shown not only the invalidity of this approach, but

  8. Ion-conductivity of thin film Li-Borate glasses

    International Nuclear Information System (INIS)

    Abouzari, M.R.S.

    2007-01-01

    In this thesis, the specific conductivity of ion-sputtered lithium borate thin films is studied. To this end, lithium borate glasses of the composition yLi 2 O.(1-y)B 2 O 3 with y=0.15, 0.20, 0.25, and 0.35 were produced as sputter targets. Films with thicknesses between 7 nm and 700 nm are deposited on silicon substrate between two AlLi electrodes. Conductivity spectra have been taken over a frequency range of 5 Hz to 2 MHz. The measurements were performed at different temperatures between 40 C and 350 C depending on the thickness and the composition of the films. The following results are derived by studying the conductivities of the films: i) The specific dc conductivity of layers with thicknesses larger than 150 nm is independent of their thicknesses; we call these layers 'thick films' and consider their conductivity as the 'base conductivity'. ii) The specific dc conductivity of layers with thicknesses smaller than 150 nm, called 'thin films', depends on the layer thickness. A nontrivial enhancement of the specific dc conductivity about three orders of magnitude for y=0.15, 0.2, and 0.25 is observed. iii) The base conductivity depends on y and at 120 C it varies between 4 x 10 -10 Ω -1 cm -1 and 2.5 x 10 -6 Ω -1 cm -1 when y varies between 0.15 and 0.35, whereas the maximum value of the specific dc conductivity of extremely thin films (with a thickness of some nanometre) seems to be independent of y and equals to the specific dc conductivity of layers with y= 0.35. Furthermore, we found in this work a physical interpretation of the so-called 'Constant Phase Element' (CPE) which is widely used in equivalent circuits for ionic conductors. This element describes correctly the depressed impedance semicircles observed in impedance spectroscopy. So far, this effect is sometimes attributed to the surface roughness. We have shown not only the invalidity of this approach, but we have also found that the depression arises from the nature of ionic motions. The model

  9. Structural investigation of Zn doped sodium bismuth borate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Bhatia, V., E-mail: vijetabhatia0712@gmail.com; Kumar, D. [Department of Physics, Punjabi University Patiala (India); Singh, D.; Singh, S. P. [Department of Physics, SGGSW University, Fatehgarh Sahib (India)

    2016-05-06

    A series of Bismuth Borate Oxide Glass samples with composition x(ZnO):(15-x)Na{sub 2}O:15Bi{sub 2}O{sub 3}:70B{sub 2}O{sub 3} (variation in x is from 6 to 12 mole %) have been prepared by conventional melt quenching technique. All the chemicals used were of Analytical Grade. In order to verify the amorphous nature of the prepared samples the X-Ray Diffraction (XRD) was done. The physical and structural properties have been explored by using the techniques such as density, molar volume and FTIR in order to understand the effect of alkali and transition metal ions on the structure of these glasses. The results obtained by these techniques are in good agreement to one another and with literature as well. With the increase in the content of ZnO, the increase in density and some variations in structural coordination (ratio of BO{sub 3} & BO{sub 4} structural units) have been observed.

  10. Structure-property relations in lanthanide borate glasses

    Science.gov (United States)

    Chakraborty, I. N.; Day, D. E.; Lapp, J. C.; Shelby, J. E.

    1985-01-01

    Glass formation in the system Ln2O3-B2O3 (Ln = Nd, Sm) was studied. Glasses could be formed in the range from 0 to 28 mol pct rare-earth oxide (Ln2O3), but liquid immiscibility in these systems limits the range of homogeneous glasses to 0 to 1.5 and 25 to 28 mol pct Ln2O3. The infrared spectra indicate that the rare-earth-rich glasses are structurally similar to rare-earth metaborates (LnB3O6) which contain (B3O6)-infinity chains. The variation in density, transformation temperature, thermal expansion coefficient, and transformation-range viscosity of these glasses with the size of the rare-earth ion is discussed. Glasses near the metaborate composition have a transformation temperature of about 700 C, which is high for binary borate glasses. Glasses could not be formed in the systems Eu2O3-, Gd2O3-, Ho2O3-, and Er2O3-B2O3, even by quenching at 1300 C/s. The sudden lack of glass formation in the system Ln2O3-B2O3 with Ln(3+) ions smaller than Sm(3+) is explained on the basis of the size effect of the Ln(3+) ion on the stability of (B3O6)-infinity chains in these metaborates.

  11. Electrochemical behaviour of silver in borate buffer solutions

    International Nuclear Information System (INIS)

    Zaky, Ayman M.; Assaf, Fawzi H.; Abd El Rehim, Sayed S.; Mohamed, Basheer

    2004-01-01

    The electrochemical behaviour of Ag in aqueous 0.15 M borax and 0.15 M boric acid buffer solution was studied under various conditions using cyclic voltammetry and potentiostatic techniques. It was found that the anodic polarization curve of Ag in borate buffer solution was characterized by the appearance of two potential regions, active and passive, prior to the oxygen evolution reaction. The active potential region was characterized by the appearance of three anodic peaks, the first two peaks A 1 and A 2 correspond to the oxidation of Ag and formation of [Ag(OH) 2 ] - soluble compound and a passive film of Ag 2 O on the electrode surface. The third anodic peak corresponds to the conversion of both [Ag(OH) 2 ] - and Ag 2 O to Ag 2 O 2 . X-ray diffraction patterns confirmed the existence of Ag 2 O and Ag 2 O 2 passive layers on the electrode surface potentiodynamically polarized up to 800 mV. Potentiostatic current transient measurements showed that the formation of Ag 2 O and Ag 2 O 2 involves a nucleation and growth mechanism under diffusion control

  12. Rare Earth Doped Lanthanum Calcium Borate Polycrystalline Red Phosphors

    Directory of Open Access Journals (Sweden)

    H. H. Xiong

    2014-01-01

    Full Text Available Single-phased Sm3+ doped lanthanum calcium borate (SmxLa2−xCaB10O19, SLCB, x=0.06 polycrystalline red phosphor was prepared by solid-state reaction method. The phosphor has two main excitation peaks located at 398.5 nm and 469.0 nm, which are nicely in accordance with the emitting wavelengths of commercial near-UV and blue light emitting diode chips. Under the excitation of 398.0 nm, the dominant red emission of Sm3+ in SLCB phosphor is centered at 598.0 nm corresponding to the transition of 4G5/2 → 6H7/2. The Eu3+ fluorescence in the red spectral region is applied as a spectroscopic probe to reveal the local site symmetry in the host lattice and, hence, Judd-Ofelt parameters Ωt  (t=2, 4 of Eu3+ in the phosphor matrix are derived to be 3.62×10-20 and 1.97×10-20 cm2, indicating a high asymmetrical and strong covalent environment around rare earth luminescence centers. Herein, the red phosphors are promising good candidates employed in white light emitting diodes (LEDs illumination.

  13. Novel method for early investigation of bioactivity in different borate bio-glasses.

    Science.gov (United States)

    Abdelghany, A M

    2013-01-01

    Some ternary borate glasses were prepared and corrosion behavior of such ternary borate glasses after immersion in aqueous dilute phosphate solution was studied using different immersion times. Fourier transform infrared (FTIR) absorption spectral measurements were done before and after immersion in the mentioned solution for extended times up to 2 days to justify the appearance of the characteristic FTIR bands due to calcium phosphate (hydroxyapatite (HA)) which is considered as the potential indication of bioactivity. Experimental IR data confirm the beginning of the appearance of FTIR bands at about 580 and 620 cm(-1) after 3 days and the complete resolution with its characteristic split form after 1 week and more. Deconvolution analysis technique (DAT) of the FTIR spectrum was employed to investigate the bioactivity of such ternary borate system after a short period of immersion. The corrosion behavior of such glasses is explained in relation to a suggested hydrolysis followed by direct dissolution mechanism. The ease of dissolution of all the borate glasses constituents explains the formation of calcium phosphate and conversion to crystalline hydroxyapatite within the borate glass matrix. X-ray diffraction may be used to retrace the structural changes and degree of crystallinity of the prepared glasses. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Na3Y3(BO3)4: a new noncentrosymmetric borate with an open-framework structure.

    Science.gov (United States)

    Shan, Faxian; Kang, Lei; Zhang, Guochun; Yao, Jiyong; Lin, Zheshuai; Xia, Mingjun; Zhang, Xinyuan; Fu, Ying; Wu, Yicheng

    2016-05-07

    A new noncentrosymmetric borate, Na3Y3(BO3)4, was grown in the Na2O-B2O3-NaF flux system. Its open-framework structure features a large hexagonal tunnel (5.92 Å in diameter), which is extremely rare in borates. First-principles calculations on its kinetic stability and optical properties were performed.

  15. 40 CFR 180.1121 - Boric acid and its salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Boric acid and its salts, borax... salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate, boric oxide (boric anhydride... its salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate, boric oxide (boric...

  16. TART calculations of neutron attenuation and neutron-induced photons on 5% and 20% borated polyethylene slabs

    International Nuclear Information System (INIS)

    Wuest, C.R.

    1993-01-01

    The coupled neutron/photon transport code TART has been used to calculate the attenuation of neutrons and the production of induced photons for neutrons incidents on 5% and 20% borated polyethylene slabs. The neutron attenuation lengths are found to be 2.4 cm and 2.9 cm for 5% and 20% borated polyethylene, respectively

  17. GEOLOGICAL FEATURES OF NEOGENE BASINS HOSTING BORATE DEPOSITS: AN OVERVIEW OF DEPOSITS AND FUTURE FORECAST, TURKEY

    Directory of Open Access Journals (Sweden)

    Cahit HELVACI

    2015-12-01

    Full Text Available The geometry, stratigraphy, tectonics and volcanic components of the borate bearing Neogene basins in western Anatolia offer some important insights into on the relationship between basin evolution, borate formation and mode of extension in western Anatolia. Some of the borate deposits in NE-SW trending basins developed along the İzmir-Balıkesir Transfer Zone (İBTZ (e.g. Bigadiç, Sultançayır and Kestelek basins, and other deposits in the NE-SW trending basins which occur on the northern side of the Menderes Core Complex (MCC are the Selendi and Emet basins. The Kırka borate deposit occurs further to the east and is located in a completely different geological setting and volcanostratigraphic succession. Boron is widely distributed; including in soil and water, plants and animals. The element boron does not exist freely by itself in nature, but rather it occurs in combination with oxygen and other elements in salts, commonly known as borates. Approximately 280 boron-bearing minerals have been identified, the most common being sodium, calcium and magnesium salts. Four main continental metallogenic borate provinces are recognized at a global scale. They are located in Anatolia (Turkey, California (USA, Central Andes (South America and Tibet (Central Asia. The origin of borate deposits is related to Cenozoic volcanism, thermal spring activity, closed basins and arid climate. Borax is the major commercial source of boron, with major supplies coming from Turkey, USA and Argentina. Colemanite is the main calcium borate and large scale production is restricted to Turkey. Datolite and szaibelyite are confined to Russia and Chinese sources. Four Main borax (tincal deposits are present in Anatolia (Kırka, California (Boron, and two in the Andes (Tincalayu and Loma Blanca. Kırka, Boron and Loma Blanca have similarities with regard to their chemical and mineralogical composition of the borate minerals. Colemanite deposits with/without probertite and

  18. New insight in the nature of surface magnetic anisotropy in iron borate

    Science.gov (United States)

    Strugatsky, M.; Seleznyova, K.; Zubov, V.; Kliava, J.

    2018-02-01

    The theory of surface magnetism of iron borate, FeBO3, has been extended by taking into consideration a crystal field contribution to the surface magnetic anisotropy energy. For this purpose, a model of distortion of the six-fold oxygen environment of iron ions in the near-surface layer of iron borate has been put forward. The spin Hamiltonian parameters for isolated Fe3+ ions in the distorted environment of the near-surface layer have been calculated using the Newman's superposition model. The crystal field contribution to the surface magnetic anisotropy energy has been calculated in the framework of the perturbation theory. The model developed allows concluding that the distortions of the iron environment produce a significant crystal field contribution to the surface magnetic anisotropy constant. The results of experimental studies of the surface magnetic anisotropy in iron borate can be described assuming the existence of relative contractions in the near-surface layer of the order of 1 %.

  19. Radiation Shielding Properties Comparison of Pb-Based Silicate, Borate, and Phosphate Glass Matrices

    Directory of Open Access Journals (Sweden)

    Suwimon Ruengsri

    2014-01-01

    Full Text Available Theoretical calculations of mass attenuation coefficients, partial interactions, atomic cross-section, and effective atomic numbers of PbO-based silicate, borate, and phosphate glass systems have been investigated at 662 keV. PbO-based silicate glass has been found with the highest total mass attenuation coefficient and then phosphate and borate glasses, respectively. Compton scattering has been the dominate interaction contributed to the different total attenuation coefficients in each of the glass matrices. The silicate and phosphate glass systems are more appropriate choices as lead-based radiation shielding glass than the borate glass system. Moreover, comparison of results has shown that the glasses possess better shielding properties than standard shielding concretes, suggesting a smaller size requirement in addition to transparency in the visible region.

  20. Dopant Concentration and Effective Atomic Number of Copper-Doped Potassium Borate Glasses

    Directory of Open Access Journals (Sweden)

    I. Hossain

    2013-01-01

    Full Text Available Copper-doped (0.5 mol% and undoped potassium borate glasses have been prepared by the composition of (100-xH3BO3 + xK2CO3, where 10 ≤ x ≤ 30 mol % by the traditional melting quenching method. The structural pattern of glasses with different composition has been identified by X-ray diffraction (XRD. The glow curves were analysed to determine various characterizations of the TLDs. Identification of the compositions and concentrations and effective atomic number of undoped and doped potassium borate glass was carried out using scanning electron microscope analysis (SEM. The dopant concentrations are found to be 0.25 mol%, while Zeff are 11.42 and 10.48 for Cu-doped and undoped potassium borate glasses, respectively.

  1. Comparision of γ -ray shielding properties of some borate glasses

    International Nuclear Information System (INIS)

    Thind, K.S.

    2003-01-01

    Several new glasses have been prepared in recent years to suit their increasing number of applications. Some of the glass compositions have distinct properties which make them the most preferred materials for certain applications such as shielding, optical fibers, electronics displays etc. The information of composition, processing and effect of environment on the glass properties is of great importance for their design and application. The shielding ability of pure elements and some mixtures have already been studied but limited attempts have been made on glasses. A good shielding glass should have high absorption cross - section for radiation and at the same time irradiation effects on its mechanical and optical properties should be small. By keeping in view of the importance of shielding ability of borate glasses, we have studied two series of different glass type: x PbO - (1-x) B 2 O 3 and x ZnO - 2xPbO - (1-3x) B 2 O 3 (where x is the mole fraction) by using narrow beam transmission method. A 2' x 2' NaI(Tl) crystal with an energy resolution of 12.5% at 662 keV of 137 Cs was used for the determination of attenuation coefficients and hence interaction cross-sections. Glass samples were prepared by using melt-quenching technique. Thickness measurement was carried out by micrometer and density was measured by Archimede's Principle using benzene as the immersion liquid. The densities of the glasses were found to increase linearly with the increase in the chemical composition of heavy metal oxide. Variations in mass attenuation coefficients and interaction cross ' sections were observed with the change in chemical composition and photon energy. It is found that these glasses have potential applications to be used as radiation shielding materials

  2. Volume and structural relaxation in compressed sodium borate glass.

    Science.gov (United States)

    Svenson, Mouritz N; Youngman, Randall E; Yue, Yuanzheng; Rzoska, Sylwester J; Bockowski, Michal; Jensen, Lars R; Smedskjaer, Morten M

    2016-11-21

    The structure and properties of glass can be modified through compression near the glass transition temperature (T g ), and such modified structure and properties can be maintained at ambient temperature and pressure. However, once the compressed glass undergoes annealing near T g at ambient pressure, the modified structure and properties will relax. The challenging question is how the property relaxation is correlated with both the local and the medium-range structural relaxation. In this paper, we answer this question by studying the volume (density) and structural relaxation of a sodium borate glass that has first been pressure-quenched from its T g at 1 GPa, and then annealed at ambient pressure under different temperature-time conditions. Using 11 B MAS NMR and Raman spectroscopy, we find that the pressure-induced densification of the glass is accompanied by a conversion of six-membered rings into non-ring trigonal boron (B III ) units, i.e. a structural change in medium-range order, and an increase in the fraction of tetrahedral boron (B IV ), i.e. a structural change in short-range order. These pressure-induced structural conversions are reversible during ambient pressure annealing near T g , but exhibit a dependence on the annealing temperature, e.g. the ring/non-ring B III ratio stabilizes at different values depending on the applied annealing temperature. We find that conversions between structural units cannot account for the pressure-induced densification, and instead we suggest the packing of structural units as the main densification mechanism.

  3. Comparative study of ion conducting pathways in borate glasses

    International Nuclear Information System (INIS)

    Hall, Andreas; Swenson, Jan; Adams, Stefan

    2006-01-01

    The conduction pathways in metal-halide doped silver, lithium, and sodium diborate glasses have been examined by bond valence analysis of reverse Monte Carlo (RMC) produced structural models of the glasses. Although all glass compositions have basically the same short-range structure of the boron-oxygen network, it is evident that the intermediate-range structure is strongly dependent on the type of mobile ion. The topography of the pathways and the coordination of the pathway sites differ distinctly between the three glass systems. The mobile silver ions in the AgI-doped glass tend to be mainly iodine-coordinated and travel in homogeneously distributed pathways located in salt-rich channels of the borate network. In the NaCl-doped glass, there is an inhomogeneous spatial distribution of pathways that reflects the inhomogeneous introduction of salt ions into the glass. However, since the salt clusters are not connected, no long-range conduction pathways are formed without including also oxygen-rich regions. The pathways in the LiCl-doped glass are slightly more evenly distributed compared to the NaCl-doped glass (but not as ordered as in the AgI-doped glass), and the regions of mainly oxygen-coordinated pathway sites are of higher importance for the long-range migration. In order to more accurately investigate how these differences in the intermediate-range order of the glasses affect the ionic conductivity, we have compared the realistic structure models to more or less randomized structures. An important conclusion from this comparison is that we find no evidence that a pronounced intermediate-range order in the atomic structure or in the network of conduction pathways, as in the AgI-doped glass, is beneficial for the dc conductivity

  4. General and Localized corrosion of Austenitic and Borated Stainless Steels in Simulated Concentrated Ground Waters

    International Nuclear Information System (INIS)

    Fix, D.; Estill, J.; Wong, L.; Rebak, R.

    2004-01-01

    Boron containing stainless steels are used in the nuclear industry for applications such as spent fuel storage, control rods and shielding. It was of interest to compare the corrosion resistance of three borated stainless steels with standard austenitic alloy materials such as type 304 and 316 stainless steels. Tests were conducted in three simulated concentrated ground waters at 90 C. Results show that the borated stainless were less resistant to corrosion than the witness austenitic materials. An acidic concentrated ground water was more aggressive than an alkaline concentrated ground water

  5. Effect of alkali ion on relaxation properties of binary alkali-borate glasses

    International Nuclear Information System (INIS)

    Lomovskoj, V.A.; Bartenev, G.M.

    1992-01-01

    Method of relaxation spectrometry were used to analyze the data on internal friction spectra of lithium, sodium, potassium and rubidium alkali-borate glasses in wide range of temperatures and frequencies. The nature of two relaxation processes was clarified: β m -process, related with mobility of alkaline metal cations, and α-process (vitrification), conditioned by system transformation from viscous-flow to vitreous state. It is shown that atomic-molecular mechanism of vitrification process changes when passing from vitreous B 2 O 3 to alkali-borate glasses

  6. Composition effect of potassium-borate glasses on their relaxation properties

    International Nuclear Information System (INIS)

    Lomovskoj, V.A.; Bartenev, G.M.

    1995-01-01

    Relaxation processes in potassium-borate glasses have been investigated in detail for the first time. It is shown that low-temperature β-process of relaxation relating to rotational mobility of the B-O bond is the same for all potassium-borate glasses and B 2 O 3 . The process of β k -relaxation related to diffusion mobility of potassium ions depends on the composition of the glasses in the same way as α-relaxation (glass formation).12 refs., 10 figs., 2 tabs

  7. The preparation and characterization of a lithium borate glass prepared by the gel technique

    Science.gov (United States)

    Weinberg, M. C.; Neilson, G. F.; Smith, G. L.; Dunn, B.; Moore, G. S.; Mackenzie, J. D.

    1985-01-01

    The preparation of an amorphous lithium borate gel by the metal organic procedure is described. In addition, a preliminary evaluation of the behavior of the gel upon heating is given. In particular the crystallization tendency of the gel is studied with the aid of DTA and X-ray diffraction, and the structural changes in the gel are monitored with the aid of IR spectroscopy. The glass produced from the lithium borate gel is compared to both the gel precursor material and a glass of similar composition prepared by conventional techniques. Specifically, the relevant water contents, crystallization behavior, and structural features are contrasted.

  8. Unusual stoichiometry control in the atomic layer deposition of manganese borate films from manganese bis(tris(pyrazolyl)borate) and ozone

    International Nuclear Information System (INIS)

    Klesko, Joseph P.; Bellow, James A.; Saly, Mark J.; Winter, Charles H.; Julin, Jaakko; Sajavaara, Timo

    2016-01-01

    The atomic layer deposition (ALD) of films with the approximate compositions Mn 3 (BO 3 ) 2 and CoB 2 O 4 is described using MnTp 2 or CoTp 2 [Tp = tris(pyrazolyl)borate] with ozone. The solid state decomposition temperatures of MnTp 2 and CoTp 2 are ∼370 and ∼340 °C, respectively. Preparative-scale sublimations of MnTp 2 and CoTp 2 at 210 °C/0.05 Torr afforded >99% recoveries with <0.1% nonvolatile residues. Self-limited ALD growth was demonstrated at 325 °C for MnTp 2 or CoTp 2 with ozone as the coreactant. The growth rate for the manganese borate process was 0.19 Å/cycle within the ALD window of 300–350 °C. The growth rate for the cobalt borate process was 0.39–0.42 Å/cycle at 325 °C. X-ray diffraction of the as-deposited films indicated that they were amorphous. Atomic force microscopy of 35–36 nm thick manganese borate films grown within the 300–350 °C ALD window showed root mean square surface roughnesses of 0.4–0.6 nm. Film stoichiometries were assessed by x-ray photoelectron spectroscopy and time of flight-elastic recoil detection analysis. The differing film stoichiometries obtained from the very similar precursors MnTp 2 and CoTp 2 are proposed to arise from the oxidizing ability of the intermediate high valent manganese oxide layers and lack thereof for cobalt.

  9. Crystal chemical characterization of mullite-type aluminum borate compounds

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, K., E-mail: Kristin.Hoffmann@uni-bremen.de [Kristallographie, FB05, Klagenfurter Straße / GEO, Universität Bremen, D-28359 Bremen (Germany); Institut für Anorganische Chemie und Kristallographie, FB02, Leobener Straße / NW2, Universität Bremen, D-28359 Bremen (Germany); Hooper, T.J.N. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Zhao, H.; Kolb, U. [Institut für Anorganische Chemie und Analytische Chemie, Jakob-Welder-WegJakob-Welder-Weg 11, Johannes Gutenberg-University Mainz, D-55128 Mainz (Germany); Murshed, M.M. [Institut für Anorganische Chemie und Kristallographie, FB02, Leobener Straße / NW2, Universität Bremen, D-28359 Bremen (Germany); MAPEX Center for Materials and Processes, Bibliothekstraße 1, Universität Bremen, D-28359 Bremen (Germany); Fischer, M.; Lührs, H. [Kristallographie, FB05, Klagenfurter Straße / GEO, Universität Bremen, D-28359 Bremen (Germany); MAPEX Center for Materials and Processes, Bibliothekstraße 1, Universität Bremen, D-28359 Bremen (Germany); Nénert, G. [Institut Laue-Langevin, 6 Rue Jules Horowitz, 38042 Grenoble Cedex 9 (France); Kudějová, P.; Senyshyn, A. [Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstr. 1, D-85748 Garching (Germany); and others

    2017-03-15

    Al-rich aluminum borates were prepared by different synthesis routes using various Al/B ratios, characterized by diffraction methods, spectroscopy and prompt gamma activation analysis. The {sup 11}B NMR data show a small amount of BO{sub 4} species in all samples. The chemical analysis indicates a trend in the Al/B ratio instead of a fixed composition. Both methods indicate a solid solution Al{sub 5−x}B{sub 1+x}O{sub 9} where Al is substituted by B in the range of 1–3%. The structure of B-rich Al{sub 4}B{sub 2}O{sub 9} (C2/m, a=1488 pm, b=553 pm, c=1502 pm, ß=90.6°), was re-investigated by electron diffraction methods, showing that structural details vary within a crystallite. In most of the domains the atoms are orderly distributed, showing no signal for the postulated channel oxygen atom O5. The absence of O5 is supported by density functional theory calculations. Other domains show a probable disordered configuration of O5 and O10, indicated by diffuse scattering along the b direction. - Graphical abstract: Projections of three-dimensional electron diffraction space of Al{sub 4}B{sub 2}O{sub 9} along the main directions. - Highlights: • The crystal structure of Al{sub 4}B{sub 2}O{sub 9} was re-evaluated. • Structural details vary among different crystals and inside Al{sub 4}B{sub 2}O{sub 9} crystallites. • Diffuse scattering indicate a probable disordered configuration of O5 and O10. • A solid solution series for Al{sub 5−x}B{sub x}O{sub 9} is indicated by PGAA and NMR spectroscopy. • The presence of BO{sub 4} groups is confirmed by {sup 11}B MAS NMR spectroscopy for Al{sub 5−x}B{sub 1+x}O{sub 9}.

  10. A mini-scale hot borate method for the isolation of total RNA from a ...

    African Journals Online (AJOL)

    By modifying and scaling down a hot borate extraction method, a quick and easy method was developed to extract total RNA from ovaries of three genotypes ranging in ages from -1 to 10 days post anthesis (dpa) with an average yield of 600 μg/gfw (gram fresh weight) and ten dpa ovaries of 64 genotypes. The method was ...

  11. Crystallization of Reduced Strontium and Barium Niobate Perovskites from Borate Fluxes.

    NARCIS (Netherlands)

    Hessen, B.; Sunshine, S.A.; Siegrist, T.; Jimenez, R.

    1991-01-01

    Single crystals of three AxNbO3 (A = Sr, Ba) reduced niobate cubic perovskites have been obtained by recrystallization of reduced ternary ceramic precursors from borate fluxes under high-vacuum. Product formation could be influenced by variation of the alkaline-earth metal oxide content of the flux,

  12. Thermoluminescence properties of the Cu-doped lithium potassium borate glass

    International Nuclear Information System (INIS)

    Aboud, Haydar; Wagiran, H.; Hussin, R.; Ali, Hassan; Alajerami, Yasser; Saeed, M.A.

    2014-01-01

    Characteristics of lithium potassium borate glasses with various copper concentrations are reported. The glasses were prepared by the melt quenching method and irradiated with photons to doses in the 0.5–4.0 Gy range. Glowing curves, dose response curves, reproducibility of the response, dose threshold, thermal fading and optical bleaching were studied

  13. Dispersive waves induced by self-defocusing temporal solitons in a beta-barium-borate crystal

    DEFF Research Database (Denmark)

    Zhou, Binbin; Bache, Morten

    2015-01-01

    We experimentally observe dispersive waves in the anomalous dispersion regime of a beta-barium-borate (BBO) crystal, induced by a self-defocusing few-cycle temporal soliton. Together the soliton and dispersive waves form an energetic octave-spanning supercontinuum. The soliton was excited...

  14. Evaluation of gamma-ray attenuation properties of bismuth borate glass systems using Monte Carlo method

    Science.gov (United States)

    Tarim, Urkiye Akar; Ozmutlu, Emin N.; Yalcin, Sezai; Gundogdu, Ozcan; Bradley, D. A.; Gurler, Orhan

    2017-11-01

    A Monte Carlo method was developed to investigate radiation shielding properties of bismuth borate glass. The mass attenuation coefficients and half-value layer parameters were determined for different fractional amounts of Bi2O3 in the glass samples for the 356, 662, 1173 and 1332 keV photon energies. A comparison of the theoretical and experimental attenuation coefficients is presented.

  15. Structure and dynamics of alkali borate glasses: a molecular dynamics study

    NARCIS (Netherlands)

    Verhoef, A.H; den Hartog, H. W.

    Structural and dynamical properties of lithium, cesium and mixed alkali (i.e., lithium and cesium) borate glasses have been studied by the molecular dynamics method. The calculations yield glass structures consisting of planar BO3 triangles and BO4 tetrahedrons with no sixfold ring structures at

  16. A study of the Eu3+ charge-transfer state in lanthanide-borate glasses

    NARCIS (Netherlands)

    Verwey, J.W.M.; Dirksen, G.J.; Blasse, G.

    1988-01-01

    The luminescence properties of the Eu[3+] ion in lanthanide- borate glasses were investigated and compared with those of Eu[3+] in Crystalline GdB3O6. In these materials the emission observed is from the [5]DO to the [7]FJ levels. The rate of nonradiative relaxation from the charge-transfer state

  17. Energy response of graphite-mixed magnesium borate TLDs to low energy x-rays

    DEFF Research Database (Denmark)

    Pelliccioni, M.; Prokic, M.; Esposito, A.

    1991-01-01

    Graphite-mixed sintered magnesium borate TL dosemeters are attractive for beta/gamma dosimetry because they combine a low energy dependence to beta-rays with near tissue or air equivalence to photon irradiations and a high sensitivity. In this paper results from the experimental measurements...

  18. Characterization and Neutron Shielding Behavior of Dehydrated Magnesium Borate Minerals Synthesized via Solid-State Method

    Directory of Open Access Journals (Sweden)

    Azmi Seyhun Kipcak

    2013-01-01

    Full Text Available Magnesium borates are one of the major groups of boron minerals that have good neutron shielding performance. In this study, dehydrated magnesium borates were synthesized by solid-state method using magnesium oxide (MgO and boron oxide (B2O3, in order to test their ability of neutron shielding. After synthesizing the dehydrated magnesium borates, characterizations were done by X-ray Diffraction (XRD, fourier transform infrared (FT-IR, Raman spectroscopy, and scanning electron microscopy (SEM. Also boron oxide (B2O3 contents and reaction yields (% were calculated. XRD results showed that seven different types of dehydrated magnesium borates were synthesized. 1000°C reaction temperature, 240 minutes of reaction time, and 3 : 2, 1 : 1 mole ratios of products were selected and tested for neutron transmission. Also reaction yields were calculated between 84 and 88% for the 3 : 2 mole ratio products. The neutron transmission experiments revealed that the 3 : 2 mole ratio of MgO to B2O3 neutron transmission results (0.618–0.655 was better than the ratio of 1 : 1 (0.772–0.843.

  19. Treatment of timber products with gaseous borate esters, Part 2: process improvement

    CSIR Research Space (South Africa)

    Turner, P

    1998-03-01

    Full Text Available This paper forms a continuation of the work on treatment of timber products with gaseous borate esters. Turner and Murphy (1995) in an earlier paper indicated that gas flow rate into the wood substrate was the principle factor limiting the rate...

  20. Tetrakis(1-imidazolyl) borate (BIM4) based zwitterionic and related molecules used as electron injection layers

    Science.gov (United States)

    Li, Huaping; Xu, Yunhua; Bazan, Guillermo C

    2013-02-05

    Tetrakis(1-imidazolyl)borate (BIm4) based zwitterionic and/or related molecules for the fabrication of PLEDs is provided. Device performances with these materials approaches that of devices with Ba/Al cathodes for which the cathode contact is ohmic. Methods of producing such materials, and electron injection layers and devices containing these materials are also provided.

  1. DVD-d. "Borat", "United 93", "Must Daalia", "Vimm 2" / Andres Laasik

    Index Scriptorium Estoniae

    Laasik, Andres, 1960-2016

    2007-01-01

    Uued mängufilmide DVD-d : Larry Charlesi "Borat" (peaosas Sacha Baron Cohen; USA 2006), Paul Greengrassi "United 93" (USA 2006), Brian De Palma "Must Daalia" ("The Black Dahlia", USA 2006), Takashi Shimizu "Vimm 2" ("The Grudge 2", USA 2006)

  2. EFFECT OF COMPLEX BORATING ON THE CHARACTERISTICS OF HARDENING GEARS IN BENCH TESTS

    Directory of Open Access Journals (Sweden)

    M. N. Pischov

    2015-01-01

    Full Text Available The paper dwells upon the necessity to increase the operating life of the toothed gearing of skidder transmission by means of strengthening by complex borating. The methodology of comparative testing of tooth gear as well as the stand construction are described. The causes of destruction of tooth gear surface strengthened by different methods have been determined.

  3. An interaction of the functionalized closo-borates with albumins: The protein fluorescence quenching and calorimetry study

    Energy Technology Data Exchange (ETDEWEB)

    Losytskyy, Mykhaylo Yu., E-mail: mlosytskyy@gmail.com [Institute of Molecular Biology and Genetics, NASU, 150 Zabolotnogo Street, 03143 Kyiv (Ukraine); Kovalska, Vladyslava B. [Institute of Molecular Biology and Genetics, NASU, 150 Zabolotnogo Street, 03143 Kyiv (Ukraine); Varzatskii, Oleg A. [V. I. Vernadsky Institute of General and Inorganic Chemistry, 32/34 Palladin Avenue, 03080 Kyiv (Ukraine); Kuperman, Marina V. [Institute of Molecular Biology and Genetics, NASU, 150 Zabolotnogo Street, 03143 Kyiv (Ukraine); Potocki, Slawomir; Gumienna-Kontecka, Elzbieta [Faculty of Chemistry, Wroclaw University, 14F. Joliot-Curie Street, 50-383 Wroclaw (Poland); Zhdanov, Andrey P. [Kurnakov Institute of General and Inorganic Chemistry, 31 Leninskii Avenue, 119991 Moscow (Russian Federation); Yarmoluk, Sergiy M. [Institute of Molecular Biology and Genetics, NASU, 150 Zabolotnogo Street, 03143 Kyiv (Ukraine); Voloshin, Yan Z. [Nesmeyanov Institute of Organoelement Compounds, 28 Vavilova Street, 119991 Moscow (Russian Federation); Zhizhin, Konstantin Yu.; Kuznetsov, Nikolai T. [Kurnakov Institute of General and Inorganic Chemistry, 31 Leninskii Avenue, 119991 Moscow (Russian Federation); Elskaya, Anna V. [Institute of Molecular Biology and Genetics, NASU, 150 Zabolotnogo Street, 03143 Kyiv (Ukraine)

    2016-01-15

    An interaction of the boron clusters closo-borates K{sub 2}[B{sub 10}H{sub 10}], K{sub 2}[B{sub 12}H{sub 12}] and their functionalized derivatives with serum proteins human (HSA) and bovine (BSA) albumins and immonoglobulin IgG as well as globular proteins β-lactoglobulin and lysozyme was characterized. The steady state and time resolved protein fluorescence quenching studies point on the binding of the closo-borate arylamine derivatives to serum albumins and discrimination of other proteins. The mechanism of the albumin fluorescence quenching by the closo-borate arylamine derivatives was proposed. The complex formation between albumin and the closo-borate molecules has been confirmed by isothermal titration calorimetry (ITC). The compound (K{sub 2}[B{sub 10}H{sub 10}]) and its arylamine derivative both interact with HSA, have close values of K{sub a} (1.4 and 1.2×10{sup 3} M{sup −1} respectively) and Gibbs energy (−17.9 and −17.5 kJ/mol respectively). However, the arylamine derivative forms complex with the higher guest/host binding ratio (4:1) comparing to the parent closo-borate (2:1). - Highlights: • Complex formation between boron clusters closo-borates and albumins was confirmed. • Functional substituent of closo-borate strongly affects its complex with albumins. • Binding of arylamine closo-borates essentially quench the albumin fluorescence. • Mechanism of tryptophan emission quenching by arylamine closo-borates was proposed.

  4. Mineralogical and geochemical studies on borate deposits from the Shahr- e - Babak playa (Khatoonabad and Robat - Marvast), Kerman province - Iran)

    OpenAIRE

    Atefeh Ghaedi; Abbas Moradian; Hamid Ahmadipour

    2017-01-01

    Introduction Borate deposits are often important constituents of economic non - marine evaporates. They produce under arid climatic conditions in playa lakes (Floyd et al., 1998). In the south – western parts of the Kerman province, such as the Khatoonabad area (east of the city of Shahr –e –Babak) and Robat – Marvast basin (west of Shahr – e – Babak), there are several borate deposits. They can be seen mainly in Sanandaj – Sirjan depressions and they occur as borate bearing nodules beneat...

  5. Optical absorption and photoluminescence properties of Er3+ doped mixed alkali borate glasses.

    Science.gov (United States)

    Ratnakaram, Y C; Kumar, A Vijaya; Naidu, D Tirupathi; Rao, J L

    2005-07-01

    An investigations of the optical absorption and fluorescence spectra of 0.2 mol% Er2O3 in mixed alkali borate glasses of the type 67.8B2O3 x xLi2O(32-x)Na2O, 67.8B2O3 x xLi2O(32-x)K2O and 67.8B2O3 x xNa2O(32-x)K2O (where x = 8, 12, 16, 20 and 24) are presented. The glasses were obtained by quenching melts consisting of H3BO3, Li2CO3, Na2CO3, K2CO3 and Er2O3 (950-1100 degrees C, 1.5-2 h) between two brass plates. Spectroscopic parameters like Racah (E1, E2 and E3), spin-orbit (xi(4f)) and configuration interaction (alpha) parameters are deduced as function of x. Using Judd-Ofelt theory, Judd-Ofelt intensity parameters (omega2, omega4 and omega6) are obtained. Radiative and non-radiative transition rates (A(T) and W(MPR)), radiative lifetimes (tauR), branching ratios (beta) and integrated absorption cross-sections (sigma) have been computed for certain excited states of Er3+ in these mixed alkali borate glasses. Emission spectra have been studied for all the three Er3+ doped mixed alkali borate glasses. The present paper throws light on the trends observed in the intensity parameters, radiative lifetimes, branching ratios and emission cross-sections as a function of x in these borate glasses, keeping in view the effect of mixed alkalies in borate glasses.

  6. Methods for separating boron from borated paraffin wax and its determination by ion chromatography

    International Nuclear Information System (INIS)

    Jeyakumar, S.

    2015-01-01

    Boron compounds are found to be useful in shielding against high-energy neutrons. In radiotherapy treatments, in order to protect occupational workers and patients from the undesirable neutron and gamma doses, paraffin wax containing B 4 C/boric acid is used. Low-level borate wastes generated from the nuclear power plants have been immobilized with paraffin wax using a concentrate waste drying system (CWDS). Borated paraffin waxes are prepared by mixing calculated amounts of either boric acid or boron carbide with the molten wax. This necessitates the determination of boron at different locations in order to check the homogeneous distribution of B over the borated wax. The determination of boron in nuclear materials is inevitable due to its high neutron absorption cross section. For the determination of boron in borated waxes, not many methods have been reported. A method based on the pyrohydrolysis extraction of boron and its quantification with ion chromatography was proposed for paraffin waxes borated with H 3 BO 3 and B 4 C. The B 4 C optimum pyrohydrolysis conditions were identified. Wax samples were mixed with U 3 O 8 , which prevents the sample from flare up, and also accelerates the extraction of boron. Pyrohydrolysis was carried out with moist O 2 at 950℃ for 60 and 90 min for wax with H 3 BO 3 and wax with B 4 C, respectively. Two simple methods of separation based on alkali extraction and melting wax in alkali were also developed exclusively for wax with H 3 BO 3 . In all the separations, the recovery of B was above 98%. During IC separation, B was separated as boron-mannitol anion complex. Linear calibration was obtained between 0.1 and 50 ppm of B, and LOD was calculated as 5 ppb (S/N=3). The reproducibility was better than 5% (RSD)

  7. The effects of borate minerals on the synthesis of nucleic acid bases, amino acids and biogenic carboxylic acids from formamide.

    Science.gov (United States)

    Saladino, Raffaele; Barontini, Maurizio; Cossetti, Cristina; Di Mauro, Ernesto; Crestini, Claudia

    2011-08-01

    The thermal condensation of formamide in the presence of mineral borates is reported. The products afforded are precursors of nucleic acids, amino acids derivatives and carboxylic acids. The efficiency and the selectivity of the reaction was studied in relation to the elemental composition of the 18 minerals analyzed. The possibility of synthesizing at the same time building blocks of both genetic and metabolic apparatuses, along with the production of amino acids, highlights the interest of the formamide/borate system in prebiotic chemistry.

  8. Unusual stoichiometry control in the atomic layer deposition of manganese borate films from manganese bis(tris(pyrazolyl)borate) and ozone

    OpenAIRE

    Klesko, Joseph P.; Bellow, James A.; Saly, Mark J.; Winter, Charles H.; Julin, Jaakko; Sajavaara, Timo

    2016-01-01

    The atomic layer deposition (ALD) of films with the approximate compositions Mn3(BO3)2 and CoB2O4 is described using MnTp2 or CoTp2 [Tp ¼ tris(pyrazolyl)borate] with ozone. The solid state decomposition temperatures of MnTp2 and CoTp2 are 370 and 340 C, respectively. Preparative-scale sublimations of MnTp2 and CoTp2 at 210 C/0.05 Torr afforded >99% recoveries with

  9. Characterization of the third-order optical nonlinearity spectrum of barium borate glasses

    Science.gov (United States)

    Santos, S. N. C.; Almeida, J. M. P.; Paula, K. T.; Tomazio, N. B.; Mastelaro, V. R.; Mendonça, C. R.

    2017-11-01

    Borate glasses have proven to be an important material for applications ranging from radiation dosimetry to nonlinear optics. In particular, B2O3-BaO based glasses are attractive to frequency generation since their barium metaborate phase (β-BaB2O4 or β-BBO) may be crystallized under proper heat treatment. Despite the vast literature covering their linear and second-order optical nonlinear properties, their third-order nonlinearities remain overlooked. This paper thus reports a study on the nonlinear refraction (n2) of BBO and BBS-DyEu glasses through femtosecond Z-scan technique. The results were modeled using the BGO approach, which showed that oxygen ions are playing a role in the nonlinear optical properties of the glasses studied here. In addition, the barium borate glasses containing rare-earths ions were found to exhibit larger nonlinearities, which is in agreement with previous studies.

  10. Switching of Magnons by Electric and Magnetic Fields in Multiferroic Borates

    Science.gov (United States)

    Kuzmenko, A. M.; Szaller, D.; Kain, Th.; Dziom, V.; Weymann, L.; Shuvaev, A.; Pimenov, Anna; Mukhin, A. A.; Ivanov, V. Yu.; Gudim, I. A.; Bezmaternykh, L. N.; Pimenov, A.

    2018-01-01

    Electric manipulation of magnetic properties is a key problem of materials research. To fulfill the requirements of modern electronics, these processes must be shifted to high frequencies. In multiferroic materials, this may be achieved by electric and magnetic control of their fundamental excitations. Here we identify magnetic vibrations in multiferroic iron borates that are simultaneously sensitive to external electric and magnetic fields. Nearly 100% modulation of the terahertz radiation in an external field is demonstrated for SmFe3 (BO3)4 . High sensitivity can be explained by a modification of the spin orientation that controls the excitation conditions in multiferroic borates. These experiments demonstrate the possibility to alter terahertz magnetic properties of materials independently by external electric and magnetic fields.

  11. Synergistic effects of zinc borate and aluminium trihydroxide on flammability behaviour of aerospace epoxy system

    Directory of Open Access Journals (Sweden)

    2009-06-01

    Full Text Available The flame retardancy of mono-component epoxy resin (RTM6, widely used for aerospace composites, treated with zinc borate (ZB, aluminium trihydroxide (ATH and their mixtures at different concentrations have been investigated by morphological and thermal characterization. Cone calorimeter data reveal that combustion behaviour, heat release rate peak (PHRR and heat release rate average (HRR Average of RTM6 resin decrease substantially when synergistic effects of zinc borate and aluminium trihydroxide intervene. Thermogravimetric (TGA results and analysis of the residue show that addition higher than 20% w/w of ZB, ATH, and their mixture greatly promotes RTM6 char formation acting as a barrier layer for the fire development. Depending upon the different used flame additives, SEM micrographs indicate that the morphology of residual char could vary from a compact amalgam-like structure, for the RTM6+ZB system, to a granular structure, characterized by very small particles of degraded resin and additive for the ATH.

  12. Spectroscopic and Radiative Properties of Several Nd3+ Ions in Borate Glass System

    Directory of Open Access Journals (Sweden)

    Juniastel Rajagukguk

    2016-08-01

    Full Text Available Radiative properties and spectroscopic studies of several Nd3+ doped Borate glass system have been reported. Judd-Ofelt intensity parameter and other parameters like oscillator strength (f, effective bandwidth (Dleff, radiative transition probabilities (AR, stimulated emission cross section (s, branching ratio (bR, radiative lifetime (tR and experimental lifetime (texp for the hypersensitive Nd3+ doped Borate Glass are listed and discussed. The variation of W2 values for the different host matrix are expressed their covalency among Nd3+ ions in the glass matrix. In this study, reported that the hypersensitive transition achieved at 4I9/2 ® 4G5/2, 2G7/2 centered at 580 – 585 nm range.

  13. Raman and Infrared Spectroscopy of Yttrium Aluminum Borate Glasses and Glass-ceramics

    Science.gov (United States)

    Bradley, J.; Brooks, M.; Crenshaw, T.; Morris, A.; Chattopadhyay, K.; Morgan, S.

    1998-01-01

    Raman spectra of glasses and glass-ceramics in the Y2O3-Al2O3-B2O3 system are reported. Glasses with B2O3 contents ranging from 40 to 60 mole percent were prepared by melting 20 g of the appropriate oxide or carbonate powders in alumina crucibles at 1400 C for 45 minutes. Subsequent heat treatments of the glasses at temperatures ranging from 600 to 800 C were performed in order to induce nucleation and crystallization. It was found that Na2CO3 added to the melt served as a nucleating agent and resulted in uniform bulk crystallization. The Raman spectra of the glasses are interpreted primarily in terms of vibrations of boron - oxygen structural groups. Comparison of the Raman spectra of the glass-ceramic samples with spectra of aluminate and borate crystalline materials reveal that these glasses crystallize primarily as yttrium aluminum borate, YAl3(BO3)4.

  14. Bone bonding ability of some borate bio-glasses and their corresponding glass-ceramic derivatives

    Directory of Open Access Journals (Sweden)

    Fatma H. Margha

    2012-12-01

    Full Text Available Ternary borate glasses from the system Na2O·CaO·B2O3 together with soda-lime-borate samples containing 5 wt.% of MgO, Al2O3, SiO2 or P2O5 were prepared. The obtained glasses were converted to their glass-ceramic derivatives by controlled heat treatment. X-ray diffraction was employed to investigate the separated crystalline phases in glass-ceramics after heat treatment of the glassy samples. The glasses and corresponding glass-ceramics after immersion in water or diluted phosphate solution for extended times were characterized by the grain method (adopted by several authors and recommended by ASTM and Fourier-transform infrared spectra to justify the formation of hydroxyapatite as an indication of the bone bonding ability. The influence of glass composition on bioactivity potential was discussed too.

  15. Exchange-mediated spin-lattice relaxation of Fe3+ ions in borate glasses.

    Science.gov (United States)

    Misra, Sushil K; Pilbrow, John R

    2007-03-01

    Spin-lattice relaxation times (T1) of two borate glasses doped with different concentrations of Fe2O3 were measured using the Electron Spin-Echo (ESE) technique at X-band (9.630 GHz) in the temperature range 2-6K. In comparison with a previous investigation of Fe3+-doped silicate glasses, the relaxation rates were comparable and differed by no more than a factor of two. The data presented here extend those previously reported for borate glasses in the 10-250K range but measured using the amplitude-modulation technique. The T1 values were found to depend on temperature (T) as T(n) with n approximately 1 for the 1% and 0.1% Fe2O3-doped glass samples. These results are consistent with spin-lattice relaxation as effected by exchange interaction of a Fe3+ spin exchange-coupled to another Fe3+ spin in an amorphous material.

  16. EFFECT OF UV LASER ON SPECTRAL PROPERTIES OF BORATE GLASSES DOPED WITH COPPER CHLORIDE NANOCRYSTALS

    Directory of Open Access Journals (Sweden)

    A. N. Babkina

    2017-01-01

    Full Text Available We present the results of the pulsed ultraviolet laser effect on the spectral properties of the potassium-aluminium-borate glasses doped with the copper chloride nanocrystals with the average size of 3.1-6.3 nm. We have studied the changes of the exciton absorption spectra of the CuCl nanocrystals induced by different duration of the laser exposure. The results show the possibility of the laser-induced crystallization and growth of the nanocrystals. For the first time the effect of the irreversible photochromism has been obtained in the potassium-aluminium-borate glasses doped with the copper chloride nanocrystals. The effect is associated with the formation of the temperature stable Cu0n colloidal color centers.

  17. Determination of boron in waters by using methyl borate generation and flame atomic-emission spectrometry

    International Nuclear Information System (INIS)

    Castillo, J.R.; Mir, J.M.; Martinez, C.; Bendicho, C.

    1985-01-01

    An improved method is proposed for the determination of boron in waters. The esterification reaction between boric acid and methanol in a concentrated sulphuric acid medium and the vaporisation of the methyl borate formed (boiling-point, 68 C) are used in the determination by boron by measuring the emission of the BO 2 radical at 548 nm. This reaction is carried out in a simple and inexpensive generator, designed for this purpose, and the heat developed in it causes the rapid volatilisation of the methyl borate. Thus no collection systems or carrier gas are required. The proposed method gives an improved detection limit and it can be applied to the determination of boron in water samples. It is both rapid and highly selective. (author)

  18. Bio-inspired borate cross-linking in ultra-stiff graphene oxide thin films.

    Science.gov (United States)

    An, Zhi; Compton, Owen C; Putz, Karl W; Brinson, L Catherine; Nguyen, SonBinh T

    2011-09-01

    Adjacent graphene oxide nanosheets in a thin-film structure have been covalently cross-linked in a fashion similar to the cell walls of higher-order plants. The resulting ultra-stiff structure exhibits a maximum storage modulus of 127 GPa that can be tuned by varying borate concentration. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Ultrasonic and Thermal Properties of Borate and Phosphate Glasses Containing Bismuth and Lead

    International Nuclear Information System (INIS)

    Aziz, Sidek Hj. Abd.; Ahmad, Hamezan; Wahab, Zaidan A.; Sulaiman, Zainal Abidin; Talib, Zainal Abidin; Shaari, A. Halim; Senin, H. B.

    2007-01-01

    Systematic series of (B2O3,P2O5)-Bi2O3-PbO glasses have been successfully prepared by using the rapid quenching technique in which each oxide content changes for every series on the basis of its weight percentage. Their amorphous natures were confirmed earlier by the x-ray diffraction technique. The experimental results show that the density of both glasses, determined by using the Archimedes principle, increases with the glass modifier content. This is due to the replacement of Bi2O3 and PbO in the borate and phosphate glassy networks. The molar volume for borate glass increases with the addition of bismuth and lead oxides, but a reverse trend occurs for the phosphate glass. The longitudinal and shear ultrasound velocities, determined by the MBS 8000 system, of both lead bismuth borate and phosphate glasses show a decreasing trend as more PbO and Bi2O3 are added to the glass system. The increase in PbO/Bi2O3 content was probably related to the progressive increase in the concentration of non-bridging oxygen (NBOs). Thermal studies of the glass, using the Labsys DTA-Setaram machine, show that the value of the glass transition temperature (Tg) is closely related to the chemical bond in the system. In lead bismuth borate glasses, the addition of more Pb2+ and Bi3+ results in a more dominant ionic bond character in the system and hence decreases Tg of the sample. However, in lead bismuth phosphate glasses, the addition of Pb2+ and Bi3+ not only failed to weaken the covalent character in P-O-P bonds, but strengthened it further, leading to an increment in the values of Tg

  20. Mechanism for converting Al2O3-containing borate glass to hydroxyapatite in aqueous phosphate solution.

    Science.gov (United States)

    Zhao, Di; Huang, Wenhai; Rahaman, Mohamed N; Day, Delbert E; Wang, Deping

    2009-05-01

    The effect of replacing varying amounts (0-2.5 mol.%) of B2O3 with Al2O3 in a borate glass on (1) the conversion of the glass to HA in an aqueous phosphate solution and (2) the compressive strength of the as-formed HA product was investigated. Samples of each glass (10 x 10 x 8 mm) were placed in 0.25 M K2HPO4 solution at 60 degrees C, and the conversion kinetics to HA were determined from the weight loss of the glass and the pH of the solution. The structure and composition of the solid reaction products were characterized using X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. While the conversion rate of the glass to HA decreased considerably with increasing Al2O3 content, the microstructure of the HA product became denser and the compressive strength of the HA product increased. The addition of SiO2 to the Al2O3-containing borate glass reversed the deterioration of the conversion rate, and produced a further improvement in the strength of the HA product. The compressive strength of the HA formed from the borate glass with 2.5 mol.% Al2O3 and 5 mol.% SiO2 was 11.1 +/- 0.2 MPa, which is equal to the highest strengths reported for trabecular bone. The results indicated that simultaneous additions of Al2O3 and SiO2 could be used to control the bioactivity of the borate glass and to enhance the mechanical strength of the HA product. Furthermore, the HA product formed from the glass containing both SiO2 and Al2O3 could be applied to bone repair.

  1. Laser- and gamma-induced transformations of optical spectra of indium-doped sodium borate glass

    CERN Document Server

    Kopyshinsky, O V; Zelensky, S E; Danilchenko, B A; Shakhov, O P

    2003-01-01

    The optical absorption and luminescence properties of indium-doped sodium borate glass irradiated by gamma-rays and by powerful UV lasers within the impurity-related absorption band are investigated experimentally. It is demonstrated that both the laser- and gamma-irradiation cause similar transformations of optical spectra in the UV and visible regions. The changes of the spectra observed are described with the use of a model which includes three types of impurity centres formed by differently charged indium ions.

  2. Borate compound content reduction in liquid radioactive waste from nuclear power plants with VVER reactor

    International Nuclear Information System (INIS)

    Szalo, A.; Zatkulak, M.

    2000-01-01

    This paper describes the current status of liquid waste (evaporator concentrates) inventory at V-1 and V-2 NPPs in Jaslovske Bohunice and the intention to separate boron from them with respect to waste minimisation and improvement of physical and chemical properties for further waste treatment and conditioning. Preliminary results of laboratory experiments concerned to borate crystallisation after pH adjustment with nitric or formic acid performed in the 1998 are given. At the present time laboratory experiments continuing - next acids, coagulation with carbon oxide, electrolytic process, ion exchange resin, study of decontamination factors, immobilization of boric acid, decrease radioactivity, purification of boron-contained compounds. Slovenske Elektrarne have accumulated 7,000 m 3 of evaporator concentrates containing 100-180 g/l borate. In order to make more storage space available, it is proposed to remove some of the borate in the liquor by precipitation as sodium tetraborate and immobilise in either cement of bitumen. The supernate can be further volume reduced by evaporation and returned to the tanks. Slovenske Elektrarne are currently evaluating acid addition to the pH 12-13 concentrate to reduce the borate solubility. However, this adds to the salt burden of the waste through this chemical addition -thus creating future increases in conditioning and disposal costs. Boric acid is used in pressurized water as a soluble neutron poison to control reactivity and also to assure a safety margin in the spent fuel pool and during refuelling operations. Boric acid is also present in the water reserved for injection into the reactor in the event of postulated accidents. (author)

  3. Order-Disorder Transitions and Superionic Conductivity in the Sodium nido-Undeca(carba)borates

    Energy Technology Data Exchange (ETDEWEB)

    Dimitrievska, Mirjana [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Tang, Wan Si [National Institute of Standards and Technology; University of Maryland; Stavila, Vitalie [Sandia National Laboratories; Zhou, Wei [National Institute of Standards and Technology; Wu, Hui [National Institute of Standards and Technology; Talin, A. Alec [Sandia National Laboratories; Udovic, Terrence J. [National Institute of Standards and Technology

    2017-11-02

    The salt compounds NaB11H14, Na-7-CB10H13, Li-7-CB10H13, Na-7,8-C2B9H12, and Na-7,9-C2B9H12 all contain geometrically similar, monocharged, nido-undeca(carba)borate anions (i.e., truncated icosohedral-shaped clusters constructed of only 11 instead of 12 {B-H} + {C-H} vertices and an additional number of compensating bridging and/or terminal H atoms). We used first-principles calculations, X-ray powder diffraction, differential scanning calorimetry, neutron vibrational spectroscopy, neutron elastic-scattering fixed-window scans, quasielastic neutron scattering, and electrochemical impedance measurements to investigate their structures, bonding potentials, phase-transition behaviors, anion orientational mobilities, and ionic conductivities compared to those of their closo-poly(carba)borate cousins. All exhibited order-disorder phase transitions somewhere between room temperature and 375 K. All disordered phases appear to possess highly reorientationally mobile anions (> ~1010 jumps s-1 above 300 K) and cation-vacancy-rich, close-packed or body-center-cubic-packed structures [like previously investigated closo-poly(carba)borates]. Moreover, all disordered phases display superionic conductivities but with generally somewhat lower values compared to those for the related sodium and lithium salts with similar monocharged 1-CB9H10- and CB11H12- closo-carbaborate anions. This study significantly expands the known toolkit of solid-state, poly(carba)borate-based salts capable of superionic conductivities and provides valuable insights into the effect of crystal lattice, unit cell volume, number of carbon atoms incorporated into the anion, and charge polarization on ionic conductivity.

  4. Synthesis, Tribological and Hydrolysis Stability Study of Novel Benzotriazole Borate Derivative

    Science.gov (United States)

    Liping, Xiong; Zhongyi, He; Liang, Qian; Lin, Mu; Aixi, Chen; Sheng, Han; Jianwei, Qiu; Xisheng, Fu

    2014-01-01

    Benzotriazole and borate derivatives have long been used as multifunctional additives to lubricants. A novel, environmentally friendly additive borate ester (NHB), which contains boron, ethanolamine, and benzotriazole groups in one molecule, was synthesized by a multi-step reaction, and its tribological properties in rapeseed oil (RSO) were investigated by a four-ball tribometer. The hydrolysis stability of the additive was investigated by half-time and open observation methods, and the mechanism of hydrolysis stability was discussed through Gaussian calculation. The novel compound NHB showed excellent performance under extreme pressure, against wearing, and in reducing friction, and its hydrolysis time is more than 1,220 times, which is better than that of triethyl borate. The mass ratio of NHB is bigger than that of the mixed liquid of triethyl borate and ethanolamine. The lone electron of amino N atoms forms a coordination effect with the B atom to compensate for the shortage of electrons in the B atom and to improve the hydrolysis stability of NHB. The surface morphology and the traces of different elements in the tribofilms formed with 1.0 wt.% NHB in were detected with scanning electron microscopy(SEM), energy dispersive X-ray spectroscopy (EDX)and X-ray photoelectron spectroscopy(XPS). The results shown that the additive caused a tribochemical reaction with the steel ball surface during the lubricating process. A mixed boundary lubrication film that contains organic nitrogen and inorganic salts, such as BN, B2O3, FeOx, Fe–O–B, and FeB, was also formed, and the formation of the lubricating film improved the tribological properties of the base oil. PMID:24465382

  5. Investigation of Er doped zinc borate glasses by low-temperature photoluminescence

    Czech Academy of Sciences Publication Activity Database

    Kostka, Petr; Kabalci, I.; Tay, T.; Gladkov, Petar; Zavadil, Jiří

    2017-01-01

    Roč. 192, DEC 2017 (2017), s. 1104-1109 ISSN 0022-2313 Institutional support: RVO:67985891 ; RVO:67985882 Keywords : borate glasses * rare- earth ions * stark levels * photoluminiscence Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass; JH - Ceramics, Fire-Resistant Materials and Glass (URE-Y) OBOR OECD: Ceramics; Ceramics (URE-Y) Impact factor: 2.686, year: 2016

  6. The structural analysis of zinc borate glass by laboratory EXAFS and X-ray diffraction measurements

    International Nuclear Information System (INIS)

    Kajinami, Akihiko; Harada, Yasushi; Inoue, Shinsuke; Deki, Shigehito; Umesaki, Norimasa

    1999-01-01

    The structure of zinc borate glass has been investigated by laboratory EXAFS and X-ray diffraction measurement as preliminary investigations for the detailed study in SPring-8. The zinc borate glass was prepared in the range from 40 to 65 mol% of zinc oxide content. The X-ray diffraction was measured by horizontal θ-θ goniometer with 60 kV and 300 mA output of Mo target. The EXAFS of zinc borate glass was measured by laboratory EXAFS system with 20 kV, 100 mA output of Mo target for the K absorption edge of zinc atom. From the X-ray diffraction and the EXAFS measurements, it is found that the zinc ion is surrounded by four oxygen atoms and formed a tetrahedral structure whose (Zn-O) distance is about 2 A and that the structure is unchanged with the zinc oxide content. The diffraction data show that the neighboring structure of boron atom transforms from BO 4 tetrahedra to BO 3 tetragonal planar structure with increasing of the zinc oxide content. (author)

  7. Microwave and conventional preparation of Zinc borate glass: Eu3+ ion as luminescent probe

    International Nuclear Information System (INIS)

    Mandal, Ashis K.; Balaji, S.; Sen, Ranjan

    2014-01-01

    Highlights: • IR transparent Zinc borate glass is prepared using microwave heating. • Glass transition temperature of microwave melted glass is found higher than that of glass prepared in conventional melting. • Low OH concentration in glass can be prepared in microwave heating. • We report higher reduction of Eu 3+ to Eu 2+ in microwave processing of Zinc borate glass. - Abstract: Transparent Zinc borate glass is melted using microwave energy as an alternative heating route to conventional resistive heating. A comparative study of the properties of the glasses prepared by both the methods is conducted by adopting X-ray diffraction (XRD), Differential scanning calorimetry (DSC), UV–VIS–NIR spectroscopy, Fourier transform infrared (FTIR) spectroscopy, Refractive Indices (RI). Amorphous nature of samples is confirmed by X-ray diffraction study. Glass transition temperature (T g ) of microwave melted glass is found ∼7–9 °C higher than that of glass prepared in conventional melting. OH content is found less than 250 ppm in microwave melted glass whereas it is above 330 ppm in conventional melted glasses. Photoluminescence study of Eu 2 O 3 doped glass prepared in microwave heating indicates higher reduction of Eu 3+ → Eu 2+ than the glass melted in conventional route. Thus, microwave processing can be an alternative energy efficient, time saving, environmental friendly glass preparation method

  8. Effect of alkali content on AC conductivity of borate glasses containing two transition metals

    International Nuclear Information System (INIS)

    Kashif, I.; Rahman, Samy A.; Soliman, A.A.; Ibrahim, E.M.; Abdel-Khalek, E.K.; Mostafa, A.G.; Sanad, A.M.

    2009-01-01

    Sodium borate glasses containing iron and molybdenum ions with the total concentration of transition ions constant and gradual substitution of sodium oxide (network modifier) by borate oxide (network former) was prepared. Densities, molar volume, DC and AC conductivities are measured. The trends of these properties are attributed to changes in the glass network structure. Their DC and AC conductivity increased with increasing NaO concentration. The increase of AC conductivity of sodium borate glasses is attributed to the chemical composition and the hopping mechanism of conduction. Measurements of the dielectric constant (ε) and dielectric loss (tan δ) as a function of frequency (50 Hz-100 kHz) and temperature (RT-600 K) indicate that the increase in dielectric constant and loss (ε and tan δ) values with increasing sodium ion content could be attributed to the assumption that Fe and Mo ions tend to assume network-forming position in the glass compositions studied. The variation of the value of frequency exponent s for all glass samples as the function of temperature at a definite frequency indicates that the value of s decreases with increasing the temperature which agrees with the correlated barrier-hopping (CBH) model.

  9. Dosimetric properties of dysprosium doped calcium magnesium borate glass subjected to Co-60 gamma ray

    Energy Technology Data Exchange (ETDEWEB)

    Omar, R. S., E-mail: ratnasuffhiyanni@gmail.com; Wagiran, H., E-mail: husin@utm.my; Saeed, M. A. [Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310 Johor Bahru (Malaysia)

    2016-01-22

    Thermoluminescence (TL) dosimetric properties of dysprosium doped calcium magnesium borate (CMB:Dy) glass are presented. This study is deemed to understand the application of calcium as the modifier in magnesium borate glass with the presence of dysprosium as the activator to be performed as TL dosimeter (TLD). The study provides fundamental knowledge of a glass system that may lead to perform new TL glass dosimetry application in future research. Calcium magnesium borate glass systems of (70-y) B{sub 2}O{sub 3} − 20 CaO – 10 MgO-(y) Dy{sub 2}O{sub 3} with 0.05  mol % ≤ y ≤ 0.7  mol % of dyprosium were prepared by melt-quenching technique. The amorphous structure and TL properties of the prepared samples were determined using powder X-ray diffraction (XRD) and TL reader; model Harshaw 4500 respectively. The samples were irradiated to Co-60 gamma source at a dose of 50 Gy. Dosimetric properties such as annealing procedure, time temperature profile (TTP) setting, optimization of Dy{sub 2}O{sub 3} concentration of 0.5 mol % were determined for thermoluminescence dosimeter (TLD) reader used.

  10. VO2+ ions in zinc lead borate glasses studied by EPR and optical absorption techniques.

    Science.gov (United States)

    Prakash, P Giri; Rao, J Lakshmana

    2005-09-01

    Electron paramagnetic resonance (EPR) and optical absorption spectra of vanadyl ions in zinc lead borate (ZnO-PbO-B2O3) glass system have been studied. EPR spectra of all the glass samples exhibit resonance signals characteristic of VO2+ ions. The values of spin-Hamiltonian parameters indicate that the VO2+ ions in zinc lead borate glasses were present in octahedral sites with tetragonal compression and belong to C4V symmetry. The spin-Hamiltonian parameters g and A are found to be independent of V2O5 content and temperature but changing with ZnO content. The decrease in Deltag( parallel)/Deltag( perpendicular) value with increase in ZnO content indicates that the symmetry around VO2+ ions is more octahedral. The decrease in intensity of EPR signal above 10 mol% of V2O5 is attributed to a fall in the ratio of the number of V4+ ions (N4) to the number of V5+ ions (N5). The number of spins (N) participating in resonance was calculated as a function of temperature for VO2+ doped zinc lead borate glass sample and the activation energy was calculated. From the EPR data, the paramagnetic susceptibility was calculated at various temperatures and the Curie constant was evaluated from the 1/chi-T graph. The optical absorption spectra show single absorption band due to VO2+ ions in tetragonally distorted octahedral sites.

  11. Evaluation of borate bioactive glass scaffolds with different pore sizes in a rat subcutaneous implantation model.

    Science.gov (United States)

    Deliormanli, Aylin M; Liu, Xin; Rahaman, Mohamed N

    2014-01-01

    Borate bioactive glass has been shown to convert faster and more completely to hydroxyapatite and enhance new bone formation in vivo when compared to silicate bioactive glass (such as 45S5 and 13-93 bioactive glass). In this work, the effects of the borate glass microstructure on its conversion to hydroxyapatite (HA) in vitro and its ability to support tissue ingrowth in a rat subcutaneous implantation model were investigated. Bioactive borate glass scaffolds, designated 13-93B3, with a grid-like microstructure and pore widths of 300, 600, and 900 µm were prepared by a robocasting technique. The scaffolds were implanted subcutaneously for 4 weeks in Sprague Dawley rats. Silicate 13-93 glass scaffolds with the same microstructure were used as the control. The conversion of the scaffolds to HA was studied as a function of immersion time in a simulated body fluid. Histology and scanning electron microscopy were used to evaluate conversion of the bioactive glass implants to hydroxyapatite, as well as tissue ingrowth and blood vessel formation in the implants. The pore size of the scaffolds was found to have little effect on tissue infiltration and angiogenesis after the 4-week implantation.

  12. In vitro evaluation of cytotoxicity of silver-containing borate bioactive glass.

    Science.gov (United States)

    Luo, Shi-Hua; Xiao, Wei; Wei, Xiao-Juan; Jia, Wei-Tao; Zhang, Chang-Qing; Huang, Wen-Hai; Jin, Dong-Xu; Rahaman, Mohamed N; Day, Delbert E

    2010-11-01

    The cytotoxicity of silver-containing borate bioactive glass was evaluated in vitro from the response of osteoblastic and fibroblastic cells in media containing the dissolution products of the glass. Glass frits containing 0-2 weight percent (wt %) Ag were prepared by a conventional melting and quenching process. The amount of Ag dissolved from the glass into a simulated body fluid (SBF), measured using atomic emission spectroscopy, increased rapidly within the first 48 h, but slowed considerably at longer times. Structural and microchemical analysis showed that the formation of a hydroxyapatite-like layer on the glass surface within 14 days of immersion in the SBF. The response of MC3T3-E1 and L929 cells to the dissolution products of the glass was evaluated using SEM observation of cell morphology, and assays of MTT hydrolysis, lactate dehydrogenase release, and alkaline phosphatase activity after incubation for up to 48 h. Cytotoxic effects were found for the borate glass containing 2 wt % Ag, but not for 0.75 and 1 wt % Ag. This borate glass containing up to ∼1 wt % Ag could provide a coating material for bacterial inhibition and enhanced bioactivity of orthopaedic implant materials such as titanium. © 2010 Wiley Periodicals, Inc.

  13. Treatment of osteomyelitis and repair of bone defect by degradable bioactive borate glass releasing vancomycin.

    Science.gov (United States)

    Xie, Zongping; Liu, Xin; Jia, Weitao; Zhang, Changqing; Huang, Wenhai; Wang, Jianqiang

    2009-10-15

    The effectiveness of a degradable and bioactive borate glass has been compared with the clinically used calcium sulfate in the treatment of osteomyelitis of rabbits, as a carrier for vancomycin. The bone infections were induced in the tibias of 65 rabbits by injecting methicillin-resistant Staphylococcus aureus (MRSA). After 3 weeks, these rabbits were distributed into 4 groups and treated by debridement. Pure borate glass (BG), vancomycin-loaded calcium sulfate (VCS) and vancomycin-loaded borate glass (VBG) were implanted into the infection sites of groups 2 to 4 respectively. After 8 weeks, the effectiveness of treatment was assessed radiographically, bacteriologically, and histopathologically. The results showed that the negative rates of MRSA examination for rabbits were 36.36%, 18.18%, 73.33% and 81.25% respectively for groups 1 to 4. Significant differences were observed radiographically, bacteriologically, and histopathologically between groups 1 and 4, groups 2 and 3, and between groups 2 and 4. The best result of treatment was observed in group 4. Radiographically, VBG was found to be mostly reabsorbed and replaced by lots of new bones, whereas, VCS was completely reabsorbed and replaced by modest new bones. Histopathologically, there were lots of newly formed bones around VBG without any foreign body response, and only modest new bones around VCS with obvious foreign body response. VBG proved to have excellent biocompatibility and to be very effective in eradicating osteomyelitis and simultaneously stimulating bone regeneration, avoiding the disadvantages of VCS.

  14. Performance of aged cement–polymer composite immobilizing borate waste simulates during flooding scenarios

    International Nuclear Information System (INIS)

    Eskander, S.B.; Bayoumi, T.A.; Saleh, H.M.

    2012-01-01

    Highlights: ► Developing of recycled Poly(ethylene terephthalate) waste to incorporate the borate waste. ► Performance of cemented waste form aged for 7 years and subjected to flooding scenario. ► SEM, X-ray diffraction, Thermal and FT-IR investigated the microstructure of cemented waste. - Abstract: An advanced composite of cement and water extended polyester based on the recycled Poly(ethylene terephthalate) waste was developed to incorporate the borate waste. Previous studies have reported the characterizations of the waste form (cement–polymer composite immobilizing borate waste simulates) after 28 days of curing time. The current work studied the performance of waste form aged for 7 years and subjected to flooding scenario during 260 days using three types of water. The state of waste form was assessed at the end of each definite interval of the water infiltration through visual examination and mechanical measurement. Scanning electron microscopy, infrared spectroscopy, X-ray diffraction and thermal analyses were used to investigate the changes that may occur in the microstructure of the waste form under aging and flooding effects. The actual experimental results indicated reasonable evidence for the durable waste form. Acceptable consistency was confirmed for the waste form even after aging 7 years and exposure to flooding scenario for 260 days.

  15. Red light emission from europium doped zinc sodium bismuth borate glasses

    Science.gov (United States)

    Hegde, Vinod; Viswanath, C. S. Dwaraka; Upadhyaya, Vyasa; Mahato, K. K.; Kamath, Sudha D.

    2017-12-01

    Zinc sodium bismuth borate (ZNBB) glasses doped with different concentrations of europium were prepared by conventional melt quenching method and characterized through the measurements of density, refractive index, X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) spectra, optical absorption, luminescence and radiative lifetimes. FTIR spectra showed seven characteristic peaks of bismuth and borate functional groups in the range of 400-1600 cm-1. The optical band gap and bonding parameters have been calculated from absorption spectra. Photoluminescence spectra recorded in the visible region with 394 nm excitation are used to calculate the Judd-Ofelt (JO) intensity parameters (Ω2 and Ω4). The JO intensity parameters have been used to calculate the radiative parameters such as branching ratio (β), stimulated emission cross-section (σse), transition probability (A) for the fluorescent level of 5D0→7F2. Decay rates through single exponential are used to calculate the lifetime (τm) of the meta-stable state 5D0 of (Eu3+ ion) these glasses. The radiative parameters measured for all these glasses show 0.7 mol% europium doped zinc sodium bismuth borate glass 5D0→7F2 transition has the potential for red laser applications. The quality of the colour emitted by the present glasses are estimated quantitatively by CIE chromaticity coordinates, which confirms the suitability of these glasses as a red emitting material for field emission technologies and LEDs.

  16. Corrosion mechanism and bioactivity of borate glasses analogue to Hench’s bioglass

    Directory of Open Access Journals (Sweden)

    Mona A. Ouis

    2012-09-01

    Full Text Available Bioactive borate glasses (from the system Na2O-CaO-B2O3-P2O5 and corresponding glass-ceramics as a new class of scaffold material were prepared by full replacement of SiO2 with B2O3 in Hench patented bioactive glass. The prepared samples were investigated by differential thermal analysis (DTA, Fourier transform infrared (FTIR spectroscopy and X-ray diffraction (XRD analysis. The DTA data were used to find out the proper heat treatment temperatures for preparation of the appropriate glass-ceramics with high crystallinity. The prepared crystalline glass-ceramics derivatives were examined by XRD to identify the crystalline phases that were precipitated during controlled thermal treatment. The FTIR spectroscopy was used to justify the formation of hydroxyapatite as an indication of the bioactivity potential or activity of the studied ternary borate glasses or corresponding glass-ceramics after immersion in aqueous phosphate solution. The corrosion results are interpreted on the basis of suggested recent views on the corrosion mechanism of such modified borate glasses in relation to their composition and constitution.

  17. Mineralogical and geochemical studies on borate deposits from the Shahr- e - Babak playa (Khatoonabad and Robat - Marvast, Kerman province - Iran

    Directory of Open Access Journals (Sweden)

    Atefeh Ghaedi

    2017-11-01

    Full Text Available Introduction Borate deposits are often important constituents of economic non - marine evaporates. They produce under arid climatic conditions in playa lakes (Floyd et al., 1998. In the south – western parts of the Kerman province, such as the Khatoonabad area (east of the city of Shahr –e –Babak and Robat – Marvast basin (west of Shahr – e – Babak, there are several borate deposits. They can be seen mainly in Sanandaj – Sirjan depressions and they occur as borate bearing nodules beneath a thin layer of soil. In general, boron considerably reduces the thermal expansion of glass, provides good resistance to vibration, high temperatures and thermal shock, and improves its toughness, strength, chemical resistance and durability. It also greatly reduces the viscosity of the glass melt. These features, and others, allow it to form superior glass for many industrial and specialty applications (Garrett, 1998. In the past, the ancient residents used them as co-melting matters. Ulexite which is frequently found in the Khatoonabad playa (at 30 km South East of Shahr Babak have Jewel properties (Ghaedi et al., 2014. Materials and methods After reviewing and Library Studies, geological field studies on the borate deposits were carried out from Shahr – e – Babak Playa. In order to take better samples, several pits were excavated with a depth of 30 cm to 1 meter so that borate minerals became apparent. X-ray diffraction analysis (IMIDRO, Karaj, and ICP AES (ALS CHEMEX, Canada methods were carried out on representative samples taken from the studied area. Discussion Field observations show that in the studied areas, borate bearing basins are fed by rivers which have originated from Sanandaj – Sirjan metamorphic rocks, Nain – Baft colored mélanges and igneous rocks of Urumieh – Dokhtar magmatic belt. Borate minerals also occur in fibrous aggregates and massive forms. Mineralogy XRD results show that the studied borate minerals mainly

  18. The effect of composition on the viscosity, crystallization and dissolution of simple borate glasses and compositional design of borate based bioactive glasses

    Science.gov (United States)

    Goetschius, Kathryn Lynn

    Borate glasses have recently been developed for a variety of medical applications, but much less is known about their structures and properties than more common silicate glasses. Melt properties and crystallization tendency for compositions in the Na2O-CaO-B2O3 system were characterized using differential thermal analysis and viscosity measurements. Characteristic viscosity (isokom) temperatures varied with the ratio between the modifier content (Na2O+CaO) and B2O3, particularly at lower temperatures, consistent with the changes in the relative concentrations of tetrahedral borons in the glass structure. Similar glasses were used to study dissolution processes in water. These alkali-alkaline earth glasses dissolve congruently and follow linear dissolution kinetics. The dissolution rates were dependent on the glass structure, with slower rates associated with greater fractions of four-coordinated boron. For glasses with a fixed alkaline earth identity, the dissolution rates increased in the order LiCaO, B2O3, SiO2, and P2O5) mixture model design was used to predict composition-property relationships to optimize the properties of new borate-based bioactive compositions for specific applications. Melt viscosity, thermal expansion coefficient, liquidus temperature and crystallization tendency were determined, as were dissolution rates in simulated body fluid (SBF).

  19. Boron isotopic composition of tertiary borate deposits in the Puna Plateau of the Central Andes, NW Argentina

    International Nuclear Information System (INIS)

    Kasemann, Simone; Franz, Gerhard; Viramonte, Jose G.; Alonso, Ricardo N.

    1998-01-01

    Full text: The most important borate deposits in South America are concentrated in the Central Andes. The Neogene deposits are located in the Puna Plateau of N W Argentina. These continental deposits are stratiform in the tectonically deformed Tertiary rocks. The largest borate accumulations Tincalayu, Sijes and Loma Blanca are part of the Late Miocene Sijes Formation, composed by different evaporitic and clastic units. In the main borate units of each location different phases of borates dominate. In Tincalayu the mayor mineral is borax with minor amounts of kernite and other rare borate minerals (ameginite, rivadavite, etc.). The principal minerals in Loma Blanca are borax with minor ulexite and inyoite. In the two main units of Sijes hydroboracite and colemanite are the major minerals; inyoite and ulexite appear subordinately. The deposition of the borates is due to a strong evaporation in playa lakes, which were fed by boron bearing thermal fluids (Alonso and Viramonte 1990). From Loma Blanca we determined δ 11 B values of ulexite (- 6.3 %0), inyoite (-12.7 %0) and terrugite (-16.2 %0); and from Tincalayu the δ 11 B values of borax (-10.5 %0), tincal (-12.2 %0) kernite (-11.7 %0) and inderite (-15.4 %0). The borates of Sijes are hydroboracite (-16.8 %0 to -17.2 %0), ulexite (-22.4 %0) and inyoite (-28.5 %0 to -29.6 %0). In order to get information about the δ 11 B values and pH of a boron solution we analysed the thermal spring of Antuco. It has a δ 11 B of -12.5%0 at a pH of 7.9. The presently forming ulexite deposit has a δ 11 B of -22.4%0. Borates within one depositional unit show a decreasing δ 11 B value sequence from the Na-Borates to the Ca-Borates related to the boron coordination of the minerals (Oi et al. 1989). The difference in the δ 11 B values excludes the precipitation in equilibrium from solutions with constant pH. According to results from previous work on Neogene borates (Turkey, USA) we interpret the borate succession due to

  20. Spectroscopic and ultrasonic investigations on structural characterization of borate glass specimen doped with transition metal ions.

    Science.gov (United States)

    Sathish, K; Thirumaran, S

    2015-08-05

    The present work describes the glass samples of composition (x% V₂O₅-(80-x)% B₂O₃-20% Na₂CO₃) VBS glass system and (x%MnO₂-(80-x)% B₂O₃-20% Na₂CO₃) in MBS glass system with mol% ranging from x=3, 6, 9, 12, 15 and 18 in steps of 3 mol% are prepared by melt quenching technique. For these prepared glass systems, sound velocity (longitudinal and shear velocities) and density have been measured. The sound velocity (longitudinal and shear) was measured by using pulse-echo technique at 5 MHz. The XRD study was carried to out to ascertain the amorphous nature of the glass specimen. Using these measured values, the elastic moduli, Poisson's ratio, Debye temperature, acoustic impedance and thermal expansion coefficient of the two glass systems were evaluated. The elastic and mechanical properties of the prepared glass systems are analyzed from ultrasonic study and the structural characterization from spectroscopic study. The effects due to the doping of transition metal ions with borate have been discussed. In the V₂O₅ doped glass system,(VBS glass system) the sound velocity, density and elastic moduli, steeply increases after 12 mol% comparatively with MnO₂ doped glass system (VBS glass system). The present study critically observes the doping of V₂O₅ with borate enhances the strengthening of network linkage and hardening of the glassy network structure than MnO₂. The IR spectral analysis reveals depolymerization of the borate network and conversion of BO₃ or BO4 units with the formation of non-bridging oxygen. The FTIR spectral studies confirm the presence of various functional groups of the sample. FTIR spectrum of sample exhibits broad absorption bands indicating the wide distribution of borate structural units. The effect of Na₂CO₃, V₂O₅ and MnO₂ contents on the structures of borate glass is evaluated from the FTIR spectra. The topological aspects of the prepared glass samples are exhaustively reported from SEM micrographs

  1. In vitro stimulation of vascular endothelial growth factor by borate-based glass fibers under dynamic flow conditions.

    Science.gov (United States)

    Chen, Sisi; Yang, Qingbo; Brow, Richard K; Liu, Kun; Brow, Katherine A; Ma, Yinfa; Shi, Honglan

    2017-04-01

    Bioactive borate glass has been recognized to have both hard and soft tissue repair and regeneration capabilities through stimulating both osteogenesis and angiogenesis. However, the underlying biochemical and cellular mechanisms remain unclear. In this study, dynamic flow culturing modules were designed to simulate the micro-environment near the vascular depletion and hyperplasia area in wound-healing regions, thus to better investigate the mechanisms underlying the biocompatibility and functionality of borate-based glass materials. Glass fibers were dosed either upstream or in contact with the pre-seeded cells in the dynamic flow module. Two types of borate glasses, doped with (1605) or without (13-93B3) CuO and ZnO, were studied along with the silicate-based glass, 45S5. Substantial fiber dissolution in cell culture medium was observed, leading to the release of ions (boron, sodium and potassium) and the deposition of a calcium phosphate phase. Different levels of vascular endothelial growth factor secretion were observed from cells exposed to these three glass fibers, and the copper/zinc containing borate 1605 fibers exhibited the most positive influence. These results indicate that dynamic studies of in vitro bioactivity provide useful information to understand the in vivo response to bioactive borate glasses. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Development of Natural Anthocyanin Dye-Doped Silica Nanoparticles for pH and Borate-Sensing Applications

    Science.gov (United States)

    Ha, Chu T.; Lien, Nghiem T. Ha; Anh, Nguyen D.; Lam, Nguyen L.

    2017-12-01

    Anthocyanin belongs to a large group of phenolic compounds called flavonoids. It is found primarily in fruits, flowers, roots and other parts of higher plants. Within the black carrot, it has been found that the cyanidin component 1,2 diol was the major anthocyanine. Since the terminal thiols potentially display chemical interactions with borate additives, anthocyanin from the black carrot can act as a sensing material for detecting borate in the environment. As a natural dye, anthocyanin responds to pH change of the medium. Here, we present an application of black carrot dyes for pH sensing and for the detection of borate additives within meats. The dyes were encapsulated within a mesoporous silica (SiO2) matrix in order to prevent the sensing materials from dissolution into the aqueous medium. The encapsulation was done in situ during preparation of silica nanoparticles (size from 100 nm to 500 nm) following an advanced Stöber method. These anthocyanin-encapsulated silica nanoparticles show a clear color change from green in an aqueous solution free of borate to GRAY-red in the presence of borate additive and red (pH 2) to green (pH 10).

  3. HP-CsB{sub 5}O{sub 8}. Synthesis and characterization of an outstanding borate exhibiting the simultaneous linkage of all structural units of borates

    Energy Technology Data Exchange (ETDEWEB)

    Sohr, Gerhard; Huppertz, Hubert [Institut fuer Allgemeine, Anorganische und Theoretische Chemie, Leopold-Franzens-Universitaet Innsbruck (Austria); Toebbens, Daniel M. [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Berlin (Germany); Schmedt auf der Guenne, Joern [Department fuer Chemie/Biologie, Universitaet Siegen (Germany)

    2014-12-15

    The new cesium pentaborate HP-CsB{sub 5}O{sub 8} is synthesized under high-pressure/high-temperature conditions of 6 GPa and 900 C in a Walker-type multianvil apparatus. The compound crystallizes in the orthorhombic space group Pnma (Z=4) with the parameters a=789.7(1), b=961.2(1), c=836.3(1) pm, V=0.6348(1) nm{sup 3}, R{sub 1}=0.0359 and wR{sub 2}=0.0440 (all data). The new structure type of HP-CsB{sub 5}O{sub 8} exhibits the simultaneous linkage of trigonal BO{sub 3} groups, corner-sharing BO{sub 4} tetrahedra, and edge-sharing BO{sub 4} tetrahedra including the presence of threefold-coordinated oxygen atoms. With respect to the rich structural chemistry of borates, HP-CsB{sub 5}O{sub 8} is the second structure type possessing this outstanding combination of the main structural units of borates in one compound. The structure consists of corrugated chains of corner- and edge-sharing BO{sub 4} tetrahedra interconnected through BO{sub 3} groups forming octagonal channels. Inside these channels, cesium is 13+3-fold coordinated by oxygen atoms. {sup 11}B MQMAS NMR spectra are analyzed to estimate the isotropic chemical shift values and quadrupolar parameters. IR and Raman spectra are obtained and compared to the calculated vibrational frequencies at the Γ-point. The high-temperature behavior is examined by means of temperature-programmed powder diffraction. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Fabrication and characterization of aluminum nitride/boron nitride nanocomposites by carbothermal reduction and nitridation of aluminum borate powders.

    Science.gov (United States)

    Kusunose, Takafumi; Sakayanagi, Nobuaki; Sekino, Tohru; Ando, Yoichi

    2008-11-01

    In order to fabricate aluminum nitride/boron nitride (AIN/BN) nanocomposites by pressureless sintering, the present study investigated the synthesis of AIN-BN nanocomposite powders by carbothermal reduction and nitridation of aluminum borate powders. Homogeneous mixtures of alumina (Al2O3), boric acid (H3BO3), and carbon powder were used to synthesize AIN/BN nanocomposite powders containing 10 and 20 vol% BN. Aluminum borate was produced by reacting Al2O3 and B2O3 above 800 degrees C, and AIN and turbostratic BN (t-BN) were produced by reacting aluminum borate with carbon powder and nitrogen gas at 1500 degrees C. Carbothermal reduction followed by nitridation yielded an AIN/BN nanocomposite powder composed of nanosized AIN and t-BN. By pressureless sintering nanocomposite AIN/BN powders containing 5 wt% Y22O3, AIN/BN nanocomposites were obtained without compromising the high thermal conductivity and high hardness.

  5. Investigations on the passivity of iron in borate and phosphate buffers, pH 8.4

    International Nuclear Information System (INIS)

    Sieber, I.V.; Hildebrand, H.; Virtanen, S.; Schmuki, P.

    2006-01-01

    In the present work surface analytical experiments (XPS and AES) on the passive film on iron formed in borate and phosphate buffers (pH 8.4) have been carried out. In the passive film formed in phosphate buffer a significant amount of phosphates is found in the outer part of the film. Boron species are not significantly incorporated in the passive film formed in borate buffer. The mechanism of the reduction of the passive film depends strongly on the electrolyte composition. In borate buffer, cathodic polarization leads to reductive dissolution of the passive film whereas in phosphate buffer the passive film is converted into metallic iron without dissolution but via laterally inhomogeneously formation of an intermediate Fe(II) phosphate layer

  6. Infrared and Raman spectroscopic studies on alkali borate glasses: evidence of mixed alkali effect.

    Science.gov (United States)

    Padmaja, G; Kistaiah, P

    2009-03-19

    A lithium-potassium-borate glass system containing manganese and iron cations has been thoroughly investigated in order to obtain information about the mixed alkali effect and the structural role of both the manganese and iron in such glass hosts. Mixed alkali borate glasses of the (30 - x)Li(2)O - xK(2)O - 10CdO/ZnO - 59B(2)O(3) (x = 0, 10, 15, 20, and 30) doped with 1MnO(2)/1Fe(2)O(3) system were prepared by a melt quench technique. The amorphous phase of the prepared glass samples was confirmed from their X-ray diffraction. The spectroscopic properties of glass samples were studied using infrared (IR) and Raman spectroscopic techniques. The density of all the prepared glasses was measured using Archimedes principle. Molar volumes were estimated from the density data. IR spectra of these glasses revealed a dramatic variation of three- and four-coordinated boron structures as a function of mixed alkali concentration. The vibrations due to Li-O, K-O, and MnO(4)/FeO(4) arrangements are consistent in all the compositions and show a nonlinear variation in the intensity with alkali content. Raman spectra of different alkali combinations with CdO and ZnO present drastic changes in the intensity of various Raman bands. The observation of disappearance and reappearance of IR and Raman bands as a function of various alkali concentrations is an important result pertaining to the mixed alkali effect in borate glasses. Acting as complementary spectroscopic techniques, both types of measurements, IR and Raman, revealed that the network structure of the studied glasses is mainly based on BO(3) and BO(4) units placed in different structural groups, the BO(3) units being dominant. The measured IR and Raman spectra of different glasses are used to clarify the optical properties of the present glasses correlating them with their structure and composition.

  7. A novel injectable borate bioactive glass cement as an antibiotic delivery vehicle for treating osteomyelitis.

    Science.gov (United States)

    Ding, Hao; Zhao, Cun-Ju; Cui, Xu; Gu, Yi-Fei; Jia, Wei-Tao; Rahaman, Mohamed N; Wang, Yang; Huang, Wen-Hai; Zhang, Chang-Qing

    2014-01-01

    A novel injectable cement composed of chitosan-bonded borate bioactive glass (BG) particles was evaluated as a carrier for local delivery of vancomycin in the treatment of osteomyelitis in a rabbit tibial model. The setting time, injectability, and compressive strength of the borate BG cement, and the release profile of vancomycin from the cement were measured in vitro. The capacity of the vancomycin-loaded BG cement to eradicate methicillin-resistant Staphylococcus aureus (MRSA)-induced osteomyelitis in rabbit tibiae in vivo was evaluated and compared with that for a vancomycin-loaded calcium sulfate (CS) cement and for intravenous injection of vancomycin. The BG cement had an injectability of >90% during the first 3 minutes after mixing, hardened within 30 minutes and, after hardening, had a compressive strength of 18 ± 2 MPa. Vancomycin was released from the BG cement into phosphate-buffered saline for up to 36 days, and the cumulative amount of vancomycin released was 86% of the amount initially loaded into the cement. In comparison, vancomycin was released from the CS cement for up 28 days and the cumulative amount released was 89%. Two months post-surgery, radiography and microbiological tests showed that the BG and CS cements had a better ability to eradicate osteomyelitis when compared to intravenous injection of vancomycin, but there was no significant difference between the BG and CS cements in eradicating the infection. Histological examination showed that the BG cement was biocompatible and had a good capacity for regenerating bone in the tibial defects. These results indicate that borate BG cement is a promising material both as an injectable carrier for vancomycin in the eradication of osteomyelitis and as an osteoconductive matrix to regenerate bone after the infection is cured.

  8. A novel injectable borate bioactive glass cement as an antibiotic delivery vehicle for treating osteomyelitis.

    Directory of Open Access Journals (Sweden)

    Hao Ding

    Full Text Available BACKGROUND: A novel injectable cement composed of chitosan-bonded borate bioactive glass (BG particles was evaluated as a carrier for local delivery of vancomycin in the treatment of osteomyelitis in a rabbit tibial model. MATERIALS AND METHODS: The setting time, injectability, and compressive strength of the borate BG cement, and the release profile of vancomycin from the cement were measured in vitro. The capacity of the vancomycin-loaded BG cement to eradicate methicillin-resistant Staphylococcus aureus (MRSA-induced osteomyelitis in rabbit tibiae in vivo was evaluated and compared with that for a vancomycin-loaded calcium sulfate (CS cement and for intravenous injection of vancomycin. RESULTS: The BG cement had an injectability of >90% during the first 3 minutes after mixing, hardened within 30 minutes and, after hardening, had a compressive strength of 18 ± 2 MPa. Vancomycin was released from the BG cement into phosphate-buffered saline for up to 36 days, and the cumulative amount of vancomycin released was 86% of the amount initially loaded into the cement. In comparison, vancomycin was released from the CS cement for up 28 days and the cumulative amount released was 89%. Two months post-surgery, radiography and microbiological tests showed that the BG and CS cements had a better ability to eradicate osteomyelitis when compared to intravenous injection of vancomycin, but there was no significant difference between the BG and CS cements in eradicating the infection. Histological examination showed that the BG cement was biocompatible and had a good capacity for regenerating bone in the tibial defects. CONCLUSIONS: These results indicate that borate BG cement is a promising material both as an injectable carrier for vancomycin in the eradication of osteomyelitis and as an osteoconductive matrix to regenerate bone after the infection is cured.

  9. Using a Borated Panel to Form a Dual Neutron-Gamma Detector

    Energy Technology Data Exchange (ETDEWEB)

    Scott Wilde; Raymond Keegan

    2008-06-20

    A borated polyethylene plane placed between a neutron source and a gamma spectrometer is used to form a dual neutron-gamma detection system. The polyethylene thermalizes the source neutrons so that they are captured by {sup 10}B to produce a flux of 478 keV gamma-rays that radiate from the plane. This results in a buildup of count rate in the detector over that from a disk of the same diameter as the detector crystal (same thickness as the panel). Radiation portal systems are a potential application of this technique.

  10. Large Faraday effect of borate glasses with high Tb3+ content prepared by containerless processing

    Science.gov (United States)

    Suzuki, Futoshi; Sato, Fumio; Oshita, Hiroyuki; Yao, Situ; Nakatsuka, Yuko; Tanaka, Katsuhisa

    2018-02-01

    Borate glasses containing a large amount of Tb3+ ions have been prepared by containerless processing. The content of Tb2O3 reached 60 mol%. The glass bearing the highest content of Tb3+ ions showed a large Faraday effect; the Verdet constant was 234 rad/T m. Annealing of the glasses in H2/N2 atmosphere resulted in a low optical absorption coefficient, leading to an extremely large magneto-optical figure of merit that was ∼1.7 times higher than that of Tb3Ga5O12 single crystal.

  11. Structural studies of lead lithium borate glasses doped with silver oxide.

    Science.gov (United States)

    Coelho, João; Freire, Cristina; Hussain, N Sooraj

    2012-02-01

    Silver oxide doped lead lithium borate (LLB) glasses have been prepared and characterized. Structural and composition characterization were accessed by XRD, FTIR, Raman, SEM and EDS. Results from FTIR and Raman spectra indicate that Ag(2)O acts as a network modifier even at small quantities by converting three coordinated to four coordinated boron atoms. Other physical properties, such as density, molar volume and optical basicity are also evaluated. Furthermore, they are also affected by the silver oxide composition. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. SYNTHESIS, STRUCTURE AND SPECTRAL PROPERTIES OF POTASSIUMALUMINA- BORATE GLASS WITH NANOCRYSTALS OF MANGANESE FERRITE

    Directory of Open Access Journals (Sweden)

    D. I. Sobolev

    2016-07-01

    Full Text Available Subject of Research.The paper presents research results of optical properties of potassium-alumina-borate glass, activated with ions of iron and manganese. The formation process of nanocrystals of manganese ferrite MnFe2O4 in potassium-alumina-borate glass host was studied. Magneto-optical characteristics were analyzed. Method. The studied glasses were synthesized by the method of charge melting in the crucible. Potassium-alumina-borate glass system was used (K2O-Al2O3-B2O3 proposed by S.A. Stepanov (Vavilov State Institute. Glass system was doped by 3 wt% of Fe2O3 and 2 wt% MnO by weight (composition 1 and 2 wt% Fe2O3 and 1 wt% MnO by weight (composition 2. The glass transition temperature was 430 °C. Segregating of the crystal phase of manganese ferrite MnFe2O4 occurred during heat treatment at 550 °C for 2 hours in a programmable muffle furnace. The absorption spectrum in the wavelength range 200-2000 nm was recorded with Perkin Elmer Lambda 650 and Varian Cary 500 spectrophotometers. The XRD patterns were obtained on Rigaku Ultima IV X-ray diffractometer by copper anode with a wavelength λ (Cu = 0.15418 nm. Magneto-optical Verde constant was measured by the angle of polarization plane rotation of the passing light through the sample when the sample is placed in magnetic field. Main Results. New technological modes of potassium-alumina-borate glass synthesis doped with ions of iron and manganese were developed and studied. It is established that during heat treatment nanocrystals of manganese ferrites are evolved with an average size of 18 nm. These glasses have a Verde constant equal to 0.9 arc.min/(cm·Oe. It is shown that obtained glasses possess high absorbance in ultra-violet and visible light spectrum. Practical Relevance. Proposed and analyzed nanoglass-ceramics could be accepted as a basis for creation of sensing environments for sensors current and magnetic field and for creation of optical isolators based on the Faraday effect.

  13. Non destructive testing of new preparations of lithium borate. Application to radiothermoluminescence dosimetry

    International Nuclear Information System (INIS)

    David, J.P.

    1986-06-01

    Summary - We recall at first some basic notions about cristalline luminescence phenomena and the different methods analysing thermoluminescence peaks. In the second part, we propose to define a way to prepare various lithium borates doped with either transition or rare-earth elements. This material whose electronic density is close to that of human tissue presents interesting applications in radiotherapy. The activator choice being made according to the best characteristics given, the resulting product is studied. Its dosimetric properties are compared with those of current standard materials used in medical or radioprotection dosimetry [fr

  14. Fourth-harmonic generation of picosecond glass laser pulses with cesium lithium borate crystals

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, L.B.; Daido, H.; Kato, Y.; Nakai, S. [Institute of Laser Engineering, Osaka University, 2-6, Yamada-Oka, Suita 565 (Japan); Zhang, T. [Yamanashi University, Faculty of Engineering, 4-3-11 Takeda, Kofu, Yamanashi 400 (Japan); Mori, Y.; Sasaki, T. [Department of Electrical Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565 (Japan)

    1996-12-01

    We report the fourth-harmonic generation of 1.5 ps, 1.053 {mu}m glass laser pulses, where group velocity mismatch plays a significant role, at intensities up to 100 GW/cm{sup 2} using newly developed crystal, cesium lithium borate (CsLiB{sub 6}O{sub 10}). Type-I doubler and type-I quadrupler were used in the fourth harmonic generation experimental scheme. Energy conversion efficiencies of 24{percent} and 53{percent} have been achieved for frequency quadrupling and doubling of the fundamental glass laser pulses, respectively. {copyright} {ital 1996 American Institute of Physics.}

  15. Visualizing the Microdistribution of Zinc Borate in Oriented Strand Board Using X-Ray Microcomputed Tomography and SEM-EDX

    OpenAIRE

    Philip D. Evans; Vinicius Lube; Holger Averdunk; Ajay Limaye; Michael Turner; Andrew Kingston; Timothy J. Senden

    2015-01-01

    Oriented strand board (OSB) is an important wood composite used in situations where fungal decay and termite attack can occur. To counter these threats, powdered zinc borate biocide is commonly added to OSB. The effectiveness of biocides depends on their even distribution within composites and resistance to leaching, but little is known about the distribution of zinc borate in OSB. Zinc is denser than wood and it should be possible to map its distribution in OSB using X-ray micro-CT. We test ...

  16. Decomposition mechanism of melamine borate in pyrolytic and thermo-oxidative conditions

    Energy Technology Data Exchange (ETDEWEB)

    Hoffendahl, Carmen; Duquesne, Sophie; Fontaine, Gaëlle; Bourbigot, Serge, E-mail: serge.bourbigot@ensc-lille.fr

    2014-08-20

    Highlights: • Decomposition of melamine borate in pyrolytic and thermo-oxidative conditions was investigated. • With increasing temperature, orthoboric acid forms boron oxide releasing water. • Melamine decomposes evolving melamine, ammonia and other fragments. • Boron oxide is transformed into boron nitride and boron nitride-oxide structures through presence of ammonia. - Abstract: Decomposition mechanism of melamine borate (MB) in pyrolytic and thermo-oxidative conditions is investigated in the condensed and gas phases using solid state NMR ({sup 13}C and {sup 11}B), X-ray photoelectron spectroscopy (XPS), pyrolysis-gas chromatography–mass spectrometry (py-GCMS) and thermogravimetric analysis coupled with a Fourier transform infrared spectrometer (TGA–FTIR). It is evidenced that orthoboric acid dehydrates to metaboric and then to boron oxide. The melamine is partially sublimated. At the same time, melamine condensates, i.e., melem and melon are formed. Melon is only formed in thermo-oxidative conditions. At higher temperature, melem and melon decompose releasing ammonia which reacts with the boron oxide to form boron nitride (BN) and BNO structures.

  17. Spectroscopic investigations on Pr3+ ions doped lead telluro-borate glasses for photonic applications

    Science.gov (United States)

    Suthanthirakumar, P.; Mariyappan, M.; Marimuthu, K.

    2018-04-01

    A new series of Lead telluro-borate glasses doped with different concentrations of Pr3+ ions (xPLTB) were prepared by melt quenching technique and their structural and spectroscopic properties were investigated by recording XRD, FTIR, optical absorption and luminescence spectral measurements. XRD measurements confirm the amorphous nature and the FTIR spectra reveal the presence of different vibrational modes of borate and tellurite networks in the prepared glasses. The bonding parameter values (δ) obtained from the absorption band positions indicates that the bonding between Pr3+ ions and their surrounding ligands is of ionic in nature. The optical band gap (Eopt) corresponding to the direct and indirect allowed transitions were determined with the framework of tauc's plot. From the luminescence spectra, important radiative parameters such as stimulated emission cross-section (σPE) , branching ratios (βR) and radiative lifetime (τR) were calculated for the dominant emission transition 3P0→3H4 (blue) in order to suggest the suitability of the studied glasses for suitable photonic applications.

  18. Performance of aged cement - polymer composite immobilizing borate waste simulates during flooding scenarios

    International Nuclear Information System (INIS)

    Eskander, S.B.; Bayoumi, T.A.; Saleh, H.M.

    2012-01-01

    An advanced composite of cement and water extended polyester based on the recycled Poly(ethylene terephthalate) waste was developed to incorporate the borate waste. Previous studies have reported the characterizations of the waste composite (cement-polymer composite immobilizing borate waste simulates) after 28 days of curing time. The current work studied the performance of waste composite aged for seven years and subjected to flooding scenario during 260 days using three types of water. The state of waste composite was assessed at the end of each definite interval of the water infiltration through visual examination and mechanical measurement. Scanning electron microscopy, infrared spectroscopy, X-ray diffraction and thermal analyses were used to investigate the changes that may occur in the microstructure of the waste composite under aging and flooding effects. The actual experimental results indicated reasonable evidence for the waste composite. Acceptable consistency was confirmed for the waste composite even after aging seven years and exposure to flooding scenario for 260 days.

  19. Thermoluminescent properties of Dy doped calcium borate based glass for dose measurement subjected to photon irradiation

    Science.gov (United States)

    Tajuddin, H. A.; WanHassan, W. M. S.; Abdul Sani, S. F..; Shaharin, Nurul Syazlin

    2017-10-01

    This study presents the thermoluminescent (TL) dosimetric properties of calcium borate glass with various dopant concentration of dysprosium (Dy). Calcium borate glass is a new potential material to be used in radiation measurement with absorption coefficient that is close to human bone. A series of glasses based on chemical equation xCaO-(100-x) B2O3 system, x = 0.1, 0.2, 0.3, 0.4, 0.5 (0glass samples were carried out and the result showed a broad peak, which confirmed the amorphous nature of the glass. The 70B2O3-30CaO glass sample was found as the most stable among other glass samples studied. Present work focuses on 70B2O3-30CaO glass of (0.01-0.4) mol% Dy-doped in order to investigate the thermoluminescence (TL) properties, in particular, dose-response and fading. The glass samples were irradiated to dose range of 0.5-4.0 Gy subjected to 6MV photon irradiations of LINAC Primus MLC 3339. TL response of 0.3 mol% Dy-doped 70B2O3-30CaO glass was found to produce highest response, with good linear dose- response relationship.

  20. Electrical Characteristics of MnO2 Doped Bismuth Borate Glass Systems

    Science.gov (United States)

    Nissar, Umair; Ahmad, Javed; Rana, Anwar Manzoor; Bukhari, S. H.; Jamil, M. T.; Khan, J. Alam; Shakeel, R.; Nadeem, M. Y.

    2018-02-01

    Transparent glasses have a large number of applications in the industry of electronics as well as optical devices. xMnO2-(25- x) Bi2O3-75H3BO3 (0 ≤ x ≤ 1.5 mol.%) transparent glasses have been prepared via melt-quench technique and characterized using dc electrical measurements, and by analyzing x-ray diffraction and Fourier transform infrared (FTIR) spectra. These characteristics were examined to understand the role of modifier oxides, i.e., Bi2O3 and MnO2 in the B2O3 glass network. Adding MnO2 into a glass network causes structural changes, which are responsible for any variations in electrical characteristics of bismuth borate glasses. Manganese bismuth borate glasses (MBBG) show Ohmic conduction at low fields; however, glasses with higher manganese content seem to conduct through bulk limited Poole-Frenkel mechanism. FTIR spectroscopy analyses depict the presence of BO3 and BO4 groups along with B-O-B and Bi-O-Bi bonding vibrations. Glasses with higher MnO2 content also show Mn-O bond vibrations. The reduction of BO4 groups and increase of BO3 units lead to the formation of non-bridging oxygens (NBOs) which are responsible for the variations in the electrical properties of these glasses.

  1. Zinc containing borate glasses and glass-ceramics: Search for biomedical applications

    Directory of Open Access Journals (Sweden)

    Amr M. Abdelghany

    2014-12-01

    Full Text Available Ternary soda lime borate glass and samples with ZnO replacing CaO up to 10 mol% were prepared and studied for their bone bonding ability. Fourier transform infrared (FTIR absorption spectra of the prepared glasses before and after immersion in simulated body fluid (SBF, for one or two weeks, showed the appearance of calcium phosphate (hydroxyapatite (HA which is an indication of bone bonding ability. X-ray diffraction patterns were measured for the glasses and indicated the presence of small peaks related to hydroxyapatite in the samples immersed in SBF. The glasses were heat treated with controlled two-step regime to convert them to their corresponding glass-ceramic derivatives. FTIR and X-ray diffraction measurements of the glass-ceramic samples (before and after immersion in SBF confirmed the appearance of HA which is influenced by ZnO content. The overall data are explained on the basis of current views about the corrosion behaviour of borate glasses including hydrolysis and direct dissolution mechanism.

  2. Thermoluminescent properties of Dy doped calcium borate based glass for dose measurement subjected to photon irradiation

    Directory of Open Access Journals (Sweden)

    Tajuddin H. A.

    2017-01-01

    Full Text Available This study presents the thermoluminescent (TL dosimetric properties of calcium borate glass with various dopant concentration of dysprosium (Dy. Calcium borate glass is a new potential material to be used in radiation measurement with absorption coefficient that is close to human bone. A series of glasses based on chemical equation xCaO-(100-x B2O3 system, x = 0.1, 0.2, 0.3, 0.4, 0.5 (0< x <100 % weight have been prepared by melt quenching method. The X-ray diffraction analysis of glass samples were carried out and the result showed a broad peak, which confirmed the amorphous nature of the glass. The 70B2O3-30CaO glass sample was found as the most stable among other glass samples studied. Present work focuses on 70B2O3-30CaO glass of (0.01-0.4 mol% Dy-doped in order to investigate the thermoluminescence (TL properties, in particular, dose-response and fading. The glass samples were irradiated to dose range of 0.5-4.0 Gy subjected to 6MV photon irradiations of LINAC Primus MLC 3339. TL response of 0.3 mol% Dy-doped 70B2O3-30CaO glass was found to produce highest response, with good linear dose- response relationship.

  3. Effects of borate-based bioactive glass on neuron viability and neurite extension.

    Science.gov (United States)

    Marquardt, Laura M; Day, Delbert; Sakiyama-Elbert, Shelly E; Harkins, Amy B

    2014-08-01

    Bioactive glasses have recently been shown to promote regeneration of soft tissues by positively influencing tissue remodeling during wound healing. We were interested to determine whether bioactive glasses have the potential for use in the treatment of peripheral nerve injury. In these experiments, degradable bioactive borate glass was fabricated into rods and microfibers. To study the compatibility with neurons, embryonic chick dorsal root ganglia (DRG) were cultured with different forms of bioactive borate glass. Cell viability was measured with no media exchange (static condition) or routine media exchange (transient condition). Neurite extension was measured within fibrin scaffolds with embedded glass microfibers or aligned rod sheets. Mixed cultures of neurons, glia, and fibroblasts growing in static conditions with glass rods and microfibers resulted in decreased cell viability. However, the percentage of neurons compared with all cell types increased by the end of the culture protocol compared with culture without glass. Furthermore, bioactive glass and fibrin composite scaffolds promoted neurite extension similar to that of control fibrin scaffolds, suggesting that glass does not have a significant detrimental effect on neuronal health. Aligned glass scaffolds guided neurite extension in an oriented manner. Together these findings suggest that bioactive glass can provide alignment to support directed axon growth. © 2013 Wiley Periodicals, Inc.

  4. Gentamicin-loaded borate bioactive glass eradicates osteomyelitis due to Escherichia coli in a rabbit model.

    Science.gov (United States)

    Xie, Zongping; Cui, Xu; Zhao, Cunju; Huang, Wenhai; Wang, Jianqiang; Zhang, Changqing

    2013-07-01

    The treatment of osteomyelitis induced by Gram-negative bacilli is rarely reported in the literature. This study established a rabbit tibia model of osteomyelitis induced by the Gram-negative bacillus Escherichia coli. Using this model, pellets composed of a chitosan-bonded mixture of borate bioactive glass and gentamicin were evaluated in vitro and in vivo for the treatment of osteomyelitis induced by Escherichia coli. Our results showed that the pellets in phosphate-buffered saline released gentamicin continuously over 26 days. Without the simultaneous use of a systemic antibiotic, the implantation of the gentamicin-loaded pellets into the osteomyelitis region of the tibia resulted in the eradication of 81.82% of infections, as determined by microbiological, histological and radiographic evaluation, and supported the ingrowth of new bone into the tibia defects after 6 weeks of implantation. The results indicate that the gentamicin-loaded borate bioactive glass implant, combining sustained drug release with the ability to support new bone formation, could provide a method for treating osteomyelitis induced by Gram-negative bacilli.

  5. Rare earth-doped lead borate glasses and transparent glass-ceramics: structure-property relationship.

    Science.gov (United States)

    Pisarski, W A; Pisarska, J; Mączka, M; Lisiecki, R; Grobelny, Ł; Goryczka, T; Dominiak-Dzik, G; Ryba-Romanowski, W

    2011-08-15

    Correlation between structure and optical properties of rare earth ions in lead borate glasses and glass-ceramics was evidenced by X-ray-diffraction, Raman, FT-IR and luminescence spectroscopy. The rare earths were limited to Eu(3+) and Er(3+) ions. The observed BO(3)↔BO(4) conversion strongly depends on the relative PbO/B(2)O(3) ratios in glass composition, giving important contribution to the luminescence intensities associated to (5)D(0)-(7)F(2) and (5)D(0)-(7)F(1) transitions of Eu(3+). The near-infrared luminescence and up-conversion spectra for Er(3+) ions in lead borate glasses before and after heat treatment were measured. The more intense and narrowing luminescence lines suggest partial incorporation of Er(3+) ions into the orthorhombic PbF(2) crystalline phase, which was identified using X-ray diffraction analysis. Copyright © 2010 Elsevier B.V. All rights reserved.

  6. Conversion of borate-based glass scaffold to hydroxyapatite in a dilute phosphate solution.

    Science.gov (United States)

    Liu, Xin; Pan, Haobo; Fu, Hailuo; Fu, Qiang; Rahaman, Mohamed N; Huang, Wenhai

    2010-02-01

    Porous scaffolds of a borate-based glass (composition in mol%: 6Na2O, 8K2O, 8MgO, 22CaO, 36B2O3, 18SiO2, 2P2O5), with interconnected porosity of approximately 70% and pores of size 200-500 microm, were prepared by a polymer foam replication technique. The degradation of the scaffolds and conversion to a hydroxyapatite-type material in a 0.02 M K2HPO4 solution (starting pH = 7.0) at 37 degrees C were studied by measuring the weight loss of the scaffolds, as well as the pH and the boron concentration of the solution. X-ray diffraction, scanning electronic microscopy and energy dispersive x-ray analysis showed that a hydroxyapatite-type material was formed on the glass surface within 7 days of immersion in the phosphate solution. Cellular response to the scaffolds was assessed using murine MLO-A5 cells, an osteogenic cell line. Scanning electron microscopy showed that the scaffolds supported cell attachment and proliferation during the 6 day incubation. The results indicate that this borate-based glass could provide a promising degradable scaffold material for bone tissue engineering applications.

  7. Mixed alkali effect on the spectroscopic properties of alkali-alkaline earth oxide borate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Srinivas, G., E-mail: srinu123g@gmail.com; Ramesh, B.; Shareefuddin, Md.; Chary, M. N.; Sayanna, R. [Department of Physics, Osmania University, Hyderabad, Telangana, India. (India)

    2016-05-06

    The mixed alkali and alkaline earth oxide borate glass with the composition xK{sub 2}O - (25-x) Li{sub 2}O-12.5BaO-12.5MgO-50B{sub 2}O{sub 3} (x = 0, 5, 10, 15, 20 and 25mol %) and doped with 1mol% CuO were prepared by the melt quenching technique. From the optical absorption spectra the optical band gap, electronic polarizability(α{sub 0}2-), interaction parameter (A), theoretical and experimental optical basicity (Λ) values were evaluated. From the Electron Paramagnetic Resonance (EPR) spectral data the number of spins (N) and susceptibility (χ) were evaluated. The values of (α{sub 0}2-), and (Λ) increases with increasing of K{sub 2}O content and electronic polarizability and interaction parameter show opposite behaviuor which may be due to the creation of non-bridging oxygens and expansion of borate network. The reciprocal of susceptibility (1/χ) and spin concentration (N) as a function of K{sub 2}O content, varied nonlinearly which may be due to creation of non-bridging oxygens in the present glass system. This may be attributed to mixed alkali effect (MAE).

  8. Nature of the hyper-Raman active vibrations of lithium borate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Simon, G; Hehlen, B; Vacher, R; Courtens, E [Laboratoire des Colloides, Verres et Nanomateriaux (LCVN), UMR 5587 CNRS, University of Montpellier II, F-34095 Montpellier (France)], E-mail: bernard.hehlen@lcvn.univ-montp2.fr

    2008-04-16

    Hyper-Raman spectra of two lithium borate glasses, 4B{sub 2}O{sub 3}:Li{sub 2}O and 2B{sub 2}O{sub 3}:Li{sub 2}O, are compared to those of pure boron oxide glass, v-B{sub 2}O{sub 3}. A mode analysis is performed using a structural model based on the symmetry of the elementary structural units (ESUs) constituting the glasses. Most spectral components arise from internal vibrations of BO{sub 3} triangles, B{sub 3}O{sub 3} boroxol rings, and BO{sub 4} tetrahedra. In particular, a mode associated with stretching motions of BO{sub 4} units can be assigned to a vibration of F{sub 2} symmetry in the T{sub d} tetrahedral point group. The hyper-Raman scattering intensity of its transverse optic component appears to be proportional to the number of BO{sub 4} units in the glass. The boson peak observed in hyper-Raman scattering arises from external modes of rigid ESUs which correspond to librational motions coupled to their translations. The scattering strength of these modes strongly decreases with increasing Li concentration. In pure v-B{sub 2}O{sub 3}, external modes of boroxols presumably dominate this scattering. The decrease in the boroxol concentration in lithium borate glasses correlates with the apparent hardening of the boson peak.

  9. Effect of TeO2 on the elastic moduli of sodium borate glasses

    International Nuclear Information System (INIS)

    Saddeek, Y.B.; Abd El Latif, Lamia

    2004-01-01

    Sodium borate glass containing tellurite as Te x Na 2-2x B 4-4x O 7-5x with x=0, 0.05, 0.15, 0.25 and 0.35 have been prepared by rapid quenching. Ultrasonic velocity (both longitudinal and shear) measurements have been made using a transducer operated at the fundamental frequency of 4 MHz at room temperature. The density was measured by the conventional Archimedes method. The elastic moduli, the Debye temperature, Poisson's ratio, and the parameters derived from the Makishima-Mackenzie model and the bond compression model have been obtained as a function of TeO 2 content. The monotonic decrease in the velocities and the elastic moduli, and the increase in the ring diameter and the ratio K bc /K e as a function of TeO 2 modifier content reveals the loose packing structure, which is attributed to the increase in the molar volume and the reduction in the vibrations of the borate lattice. The observed results confirm that the addition of TeO 2 changes the rigid character of Na 2 B 4 O 7 to a matrix of ionic behaviour bonds (NBOs). This is due to the creation of more and more discontinuities and defects in the glasses, thus breaking down the borax structure

  10. Photochemistry of peroxoborates: borate inhibition of the photodecomposition of hydrogen peroxide.

    Science.gov (United States)

    Rey, Sébastien; Davies, D Martin

    2006-12-13

    The UV absorbance and photochemical decomposition kinetics of hydrogen peroxide in borate/boric acid buffers were investigated as a function of pH, total peroxide concentration, and total boron concentration. At higher pH borate/boric acid inhibits the photodecomposition of hydrogen peroxide (molar absorptivity and quantum yield of H(2)O(2) and HO(2) (-), (19.0+/-0.3) M(-1) cm(-1) and 1, and (237+/-7) M(-1) cm(-1) and 0.8+/-0.1, respectively). The results are consistent with the equilibrium formation of the anions monoperoxoborate, K(BOOH)=[H(+)][HOOB(OH)(3) (-)]/([B(OH)(3)][H(2)O(2)]), 2.0 x 10(-8), R. Pizer, C. Tihal, Inorg. Chem. 1987, 26, 3639-3642, and monoperoxodiborate, K(BOOB)=[BOOB(2-)]/([B(OH)(4) (-)][HOOB(OH)(3) (-)]), 1.0+/-0.3 or 4.3+/-0.9, depending upon the conditions, with molar absorptivity, (19+/-1) M(-1) cm(-1) and (86+/-15) M(-1) cm(-1), respectively, and respective quantum yields, 1.1+/-0.1 and 0.04+/-0.04. The low quantum yield of monoperoxodiborate is discussed in terms of the slower diffusion apart of incipient (.)OB(OH)(3) (-) radicals than may be possible for (.)OH radicals, or a possible oxygen-bridged cyclic structure of the monoperoxodiborate.

  11. Inorganic pigments doped with tris(pyrazol-1-yl)borate lanthanide complexes: A photoluminescence study

    Energy Technology Data Exchange (ETDEWEB)

    Gheno, Giulia, E-mail: giulia.gheno@unive.it [Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca’ Foscari di Venezia, Dorsoduro 2137, 30123 Venezia (Italy); Bortoluzzi, Marco; Ganzerla, Renzo [Dipartimento di Scienze Molecolari e Nanosistemi, Università Ca’ Foscari di Venezia, Dorsoduro 2137, 30123 Venezia (Italy); Enrichi, Francesco [CIVEN, Coordinamento Interuniversitario Veneto per le Nanotecnologie, Via delle Industrie 5, 30175 Marghera, Venezia (Italy)

    2014-01-15

    The inorganic pigments malachite, Egyptian blue, Ercolano blue and chrome yellow have been doped with the neutral homoleptic Ln(III) complex Ln(Tp){sub 3} (Ln=Eu, Tb; Tp=hydrotris(pyrazol-1-yl)borate) in the presence of arabic gum or acrylic emulsion as binders, in order to obtain photoluminescent materials of interest for cultural heritage restoration. The doped pigments have shown emissions associated to f–f transitions in the visible range upon excitation with UV light. Thermal and UV-light ageings have been carried out. In all the cases the photoluminescent behaviour is maintained, but in the cases of acrylic-based paints emission spectra and lifetimes are strongly influenced by thermal treatments. The choice of binder and pigments influences the photoluminescent behaviour of the corresponding film paints. -- Highlights: • Inorganic pigments doped with photoluminescent lanthanide complexes. • Hydrotris(pyrazol-1-yl)borate (Tp) as antenna-ligand for Eu(III) and Tb(III). • Emission associated to f–f transitions upon excitation with UV light. • Photoluminescence of paints influenced by the choice of binder and pigments. • Photoluminescence after ageing depending upon the type of binder.

  12. Preparation of photoluminescent PMMA doped with tris(pyrazol-1-yl)borate lanthanide complexes

    Energy Technology Data Exchange (ETDEWEB)

    Bortoluzzi, Marco, E-mail: markos@unive.it [Dipartimento di Scienze Molecolari e Nanosistemi, Universita Ca' Foscari di Venezia, Dorsoduro 2137, 30123 Venezia (Italy); Paolucci, Gino, E-mail: paolucci@unive.it [Dipartimento di Scienze Molecolari e Nanosistemi, Universita Ca' Foscari di Venezia, Dorsoduro 2137, 30123 Venezia (Italy); Gatto, Mattia; Roppa, Stefania [Dipartimento di Scienze Molecolari e Nanosistemi, Universita Ca' Foscari di Venezia, Dorsoduro 2137, 30123 Venezia (Italy); Enrichi, Francesco [CIVEN, Coordinamento Interuniversitario Veneto per le Nanotecnologie, Via delle Industrie 5, 30175 Marghera (Venezia) (Italy); Ciorba, Serena; Richards, Bryce S. [School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS (United Kingdom)

    2012-09-15

    The neutral homoleptic Ln(III) complex Ln(Tp){sub 3} (Ln=Sm, Eu, Tb, Yb; Tp=hydrotris(pyrazol-1-yl)borate) were used as dopants for the preparation of novel photoluminescent poly(methyl methacrylate) glasses indicated as Ln(Tp){sub 3}-PMMA. The doped polymers containing samarium, europium and terbium derivatives showed emission associated to f-f transitions in the visible range upon excitation with UV light, while a NIR emission was obtained from Yb(Tp){sub 3}-PMMA. The maximum incident wavelength able to induce emissions from the Ln(Tp){sub 3}-doped polymers depends upon the choice of the lanthanide ion. No meaningful antenna-effect was instead observed using dysprosium as metal centre. - Highlights: Black-Right-Pointing-Pointer Polymers doped with photoluminescent lanthanide complexes. Black-Right-Pointing-Pointer Hydrotris(pyrazol-1-yl)borate (Tp) as antenna-ligand for Sm(III), Eu(III), Tb(III) and Yb(III). Black-Right-Pointing-Pointer Emission associated to f-f transitions upon excitation with UV light. Black-Right-Pointing-Pointer No antenna-effect for dysprosium derivative. Black-Right-Pointing-Pointer Photoluminescence excitation spectra are dependent upon the lanthanide ion.

  13. Synthesis and characterization of borate based and AgGaS{sub 2} materials

    Energy Technology Data Exchange (ETDEWEB)

    Dhanasekaran, R, E-mail: rdhanasekaran@annauniv.edu [Crystal Growth Centre, Anna University-Chennai, Chennai 600 025 (India)

    2009-07-15

    In recent years, there has been tremendous development in the fabrication of suitable materials for optoelectronic, laser, photovoltaic devices, acousto-optic, sonar and infrared detectors applications. Mastering in synthesis, growth and characterization is an essential requirement for fully realizing the potential applications of the materials technology for the construction of novel devices for Laser, microwave, optoelectronic and other applications. The anisotropy in the crystals gives them enhanced properties as required in the field of non-linear optics. With the advent of laser sources, a nonlinear optical phenomenon has got tremendous interest and nonlinear optical (NLO) materials play a key role in the development of laser technology. Because of the variety and complexity of the material systems involved, several approaches towards synthesis, growth and characterization have been developed during the past decades. Laser materials can be classified into Inorganic, Organic and Semi organic categories. Urea, DAST, mNA, POM, NPP, MAP are examples of organic family crystals where as L-Arginine phosphate (LAP), Zinc tris thiourea sulphate (ZTS), BTCC, ZCTC belongs to semi organic class. Inorganic NLO crystals are Potassium titanyl phosphate (KTP), GdYCOB, KAB, Beta Barium Borate (BBO), LBO, KDP and LiNbO{sub 3}. Synthesis and characterization of technologically important Borate based materials for NLO applications will be reviewed. The raising demand for UV lasers has led to the development of various NLO materials. A series of borate materials - Rare earth calcium oxy borate (RECOB) with the general chemical formula RECa{sub 4}O(BO{sub 3}){sub 3} with RE=Y,Gd, Nd, Sm, etc. are reported to be synthesized from their repective melts. The RECOB crystals are excellent NLO materials and when doped with 'laser-active' ions (Nd{sup 3+}, Yb{sup 3+}), they become efficient laser-host crystals. The single crystals of YCOB were grown by flux technique using boron

  14. Improved green-light-emitting pyrotechnic formulations based on tris(2,2,2-trinitroethyl)borate and boron carbide.

    Science.gov (United States)

    Klapötke, Thomas M; Krumm, Burkhard; Rusan, Magdalena; Sabatini, Jesse J

    2014-08-28

    Green-light-emitting pyrotechnic compositions based on tris(2,2,2-trinitroethyl)borate (TNEB) and boron carbide have been investigated. The best performing formulations were found to be insensitive to various ignition stimuli, and exhibited very high spectral purities and luminosities compared to previously reported green-light-emitting formulations.

  15. A novel injectable borate bioactive glass cement for local delivery of vancomycin to cure osteomyelitis and regenerate bone.

    Science.gov (United States)

    Cui, Xu; Zhao, Cunju; Gu, Yifei; Li, Le; Wang, Hui; Huang, Wenhai; Zhou, Nai; Wang, Deping; Zhu, Yi; Xu, Jun; Luo, Shihua; Zhang, Changqing; Rahaman, Mohamed N

    2014-03-01

    Osteomyelitis (bone infection) is often difficult to cure. The commonly-used treatment of surgical debridement to remove the infected bone combined with prolonged systemic and local antibiotic treatment has limitations. In the present study, an injectable borate bioactive glass cement was developed as a carrier for the antibiotic vancomycin, characterized in vitro, and evaluated for its capacity to cure osteomyelitis in a rabbit tibial model. The cement (initial setting time = 5.8 ± 0.6 min; compressive strength = 25.6 ± 0.3 MPa) released vancomycin over ~25 days in phosphate-buffered saline, during which time the borate glass converted to hydroxyapatite (HA). When implanted in rabbit tibial defects infected with methicillin-resistant Staphylococcus aureus (MRSA)-induced osteomyelitis, the vancomycin-loaded cement converted to HA and supported new bone formation in the defects within 8 weeks. Osteomyelitis was cured in 87 % of the defects implanted with the vancomycin-loaded borate glass cement, compared to 71 % for the defects implanted with vancomycin-loaded calcium sulfate cement. The injectable borate bioactive glass cement developed in this study is a promising treatment for curing osteomyelitis and for regenerating bone in the defects following cure of the infection.

  16. In vitro bioactivity, cytocompatibility, and antibiotic release profile of gentamicin sulfate-loaded borate bioactive glass/chitosan composites.

    Science.gov (United States)

    Cui, Xu; Gu, Yifei; Li, Le; Wang, Hui; Xie, Zhongping; Luo, Shihua; Zhou, Nai; Huang, Wenhai; Rahaman, Mohamed N

    2013-10-01

    Borate bioactive glass-based composites have been attracting interest recently as an osteoconductive carrier material for local antibiotic delivery. In the present study, composites composed of borate bioactive glass particles bonded with a chitosan matrix were prepared and evaluated in vitro as a carrier for gentamicin sulfate. The bioactivity, degradation, drug release profile, and compressive strength of the composite carrier system were studied as a function of immersion time in phosphate-buffered saline at 37 °C. The cytocompatibility of the gentamicin sulfate-loaded composite carrier was evaluated using assays of cell proliferation and alkaline phosphatase activity of osteogenic MC3T3-E1 cells. Sustained release of gentamicin sulfate occurred over ~28 days in PBS, while the bioactive glass converted continuously to hydroxyapatite. The compressive strength of the composite loaded with gentamicin sulfate decreased from the as-fabricated value of 24 ± 3 MPa to ~8 MPa after immersion for 14 days in PBS. Extracts of the soluble ionic products of the borate glass/chitosan composites enhanced the proliferation and alkaline phosphatase activity of MC3T3-E1 cells. These results indicate that the gentamicin sulfate-loaded composite composed of chitosan-bonded borate bioactive glass particles could be useful clinically as an osteoconductive carrier material for treating bone infection.

  17. Synthesis and characterization of cerium- and gallium-containing borate bioactive glass scaffolds for bone tissue engineering.

    Science.gov (United States)

    Deliormanlı, Aylin M

    2015-02-01

    Bioactive glasses are widely used in biomedical applications due to their ability to bond to bone and even to soft tissues. In this study, borate based (13-93B3) bioactive glass powders containing up to 5 wt% Ce2O3 and Ga2O3 were prepared by the melt quench technique. Cerium (Ce+3) and gallium (Ga+3) were chosen because of their low toxicity associated with bacteriostatic properties. Bioactive glass scaffolds were fabricated using the polymer foam replication method. In vitro degradation and bioactivity of the scaffolds were evaluated in SBF under static conditions. Results revealed that the cerium- and gallium-containing borate glasses have much lower degradation rates compared to the bare borate glass 13-93B3. In spite of the increased chemical durability, substituted glasses exhibited a good in vitro bioactive response except when the Ce2O3 content was 5 wt%. Taking into account the high in vitro hydroxyapatite forming ability, borate glass scaffolds containing Ce+3 and Ga+3 therapeutic ions are promising candidates for bone tissue engineering applications.

  18. Local structure of alkalis in mixed-alkali borate glass to elucidate the origin of mixed-alkali effect

    Directory of Open Access Journals (Sweden)

    Yomei Tokuda

    2015-12-01

    Full Text Available We report the structural analysis of Na+ and Cs+ in sodium cesium borate crystals and glasses using 23Na and 133Cs magic-angle spinning nuclear magnetic resonance (MAS NMR spectroscopy. The composition dependence of NMR spectra of the borate was similar to that of the silicate: (1 the peak position of cesium borate crystals shifted to upfield for structures with larger Cs+ coordination numbers, (2 the MAS NMR spectra of xNa2O-yCs2O-3B2O3 (x = 0, 0.25, 0.5, 0.75, 1.0, x + y = 1 glass showed that the average coordination number (CN of both the alkali cations decreases with increasing Cs+/(Na+ + Cs+ ratio. However, the degree of decrement in borates is much smaller than that in silicates. We have considered that the small difference in CN is due to 4-coordinated B, because it is electrically compensated by the alkali metal ions resulting in the restriction of having various coordinations of O to alkali metal.

  19. Tribological characteristics of monodispersed cerium borate nanospheres in biodegradable rapeseed oil lubricant

    Energy Technology Data Exchange (ETDEWEB)

    Boshui, Chen, E-mail: boshuichen@163.com; Kecheng, Gu; Jianhua, Fang; Jiang, Wu; Jiu, Wang; Nan, Zhang

    2015-10-30

    Graphical abstract: - Highlights: • Monodispersed stearic acid-capped cerium borate composite nanoparticles were prepared by hydrothermal method. Their morphologies, element compositions, size distributions, crystal and chemical structures, hydrophobic characteristics were also characterized. • The surface-capped cerium borate nanoparticles exhibited excellent dispersing stability in rapeseed oil. As new lubricating additives, they were also outstanding in enhancing friction-reducing and anti-wear capacities of rapeseed oil in biodegradable rapeseed oil. The results presented in this paper would be of important significance for developing green lubricants and lubricant additives. • The prominent tribological performances of SA/CeBO{sub 3} in rapeseed oil were investigated and attributed to the formation of a composite boundary lubrication film mainly composed of lubricous tribochemical species on the tribo-surfaces. - Abstract: Stearic acid-capped cerium borate composite nanoparticles, abbreviated as SA/CeBO{sub 3}, were prepared by hydrothermal method. The morphologies, element compositions, size distributions, crystal and chemical structures, hydrophobic characteristics, of SA/CeBO{sub 3} were characterized by scanning electron microscope, energy dispersive X-ray spectrometer, dynamic laser particle size analyzer, X-ray diffraction, and Fourier transform infrared spectrometer, respectively. The friction and wear performances of SA/CeBO{sub 3} as a lubricating additive in a rapeseed oil were evaluated on a four-ball tribo-tester. The tribochemical characteristics of the worn surfaces were investigated by X-ray photoelectron spectroscopy. The results showed that the hydrophobic SA/CeBO{sub 3} were monodispersed nanospheres with an average diameter of 8 nm, and exhibited excellent dispersing stability in rapeseed oil. Meanwhile, SA/CeBO{sub 3} nanospheres were outstanding in enhancing friction-reducing and anti-wear capacities of rapeseed oil. The prominent

  20. Solubility and peculiarities of the yttrium-aluminium borate crystal growth

    Energy Technology Data Exchange (ETDEWEB)

    Azizov, A.V.; Leonyuk, N.I.; Rezvyj, V.R.; Timchenko, T.I.; Belov, N.V. (Moskovskij Gosudarstvennyj Univ. (USSR))

    The nature of crystallization media and crystallization peculiarities of YAl/sub 3/(BO/sub 3/)/sub 4/ yttrium-alluminium borate (YAB) were investigated. The investigation of YAB solubility was conducted in the melts of two different compositions: 88.1K/sub 2/Mo/sub 2/O/sub 10/-3.5V/sub 2/O/sub 3/-8.4B/sub 2/O/sub 3/ (1) and 89.5K/sub 2/Mo/sub 3/O/sub 10/ - - 10.5B/sub 2/O/sub 3/ (2) at 1060-900 deg C. The YAB crystals obtained from different crystallization media had different habit and morphology. The revealed peculiarities are significant for the choice of the YAB crystal growing conditions on orientated seedings: more rapid growth can be exercised along the (0001) face from the solution in the melt (2).

  1. Broad-spectrum antibacterial properties of metal-ion doped borate bioactive glasses for clinical applications

    Science.gov (United States)

    Ottomeyer, Megan

    Bioactive glasses with antimicrobial properties can be implemented as coatings on medical devices and implants, as well as a treatment for tissue repair and prevention of common hospital-acquired infections such as MRSA. A borate-containing glass, B3, is also undergoing clinical trials to assess wound-healing properties. The sensitivities of various bacteria to B3, B3-Ag, B3-Ga, and B3-I bioactive glasses were tested. In addition, the mechanism of action for the glasses was studied by spectroscopic enzyme kinetics experiments, Live-Dead staining fluorescence microscopy, and luminescence assays using two gene fusion strains of Escherichia coli. It was found that gram-positive bacteria were more sensitive to all four glasses than gram negative bacteria, and that a single mechanism of action for the glasses is unlikely, as the rates of catalysis for metabolic enzymes as well as membrane permeability were altered after glass exposure.

  2. Thermal properties of borate crystals for high power optical parametric chirped-pulse amplification.

    Science.gov (United States)

    Riedel, R; Rothhardt, J; Beil, K; Gronloh, B; Klenke, A; Höppner, H; Schulz, M; Teubner, U; Kränkel, C; Limpert, J; Tünnermann, A; Prandolini, M J; Tavella, F

    2014-07-28

    The potential of borate crystals, BBO, LBO and BiBO, for high average power scaling of optical parametric chirped-pulse amplifiers is investigated. Up-to-date measurements of the absorption coefficients at 515 nm and the thermal conductivities are presented. The measured absorption coefficients are a factor of 10-100 lower than reported by the literature for BBO and LBO. For BBO, a large variation of the absorption coefficients was found between crystals from different manufacturers. The linear and nonlinear absorption coefficients at 515 nm as well as thermal conductivities were determined for the first time for BiBO. Further, different crystal cooling methods are presented. In addition, the limits to power scaling of OPCPAs are discussed.

  3. Physical and optical properties of sodium borate glasses doped with Dy3+ ions

    Science.gov (United States)

    Alajerami, Y. S. M.; Abushab, K. M.; Alagha, S. I.; Mhareb, M. H. A.; Saidu, A.; Kodeh, F. S.; Ramadan, Kh.

    2017-09-01

    The photoluminescence, optical and physical properties of sodium borate (NB) doped with different concentrations of Dy3+ were determined and well discussed. The samples were prepared by the melt-quenching technique and characterized by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Photoluminescence and absorption spectra of NB glasses doped with different concentrations of Dy3+ are reported. Ten absorption bands with hypersensitive transition at 1272 nm (6F11/2 →6H 9/2) and two emission bands for the transitions at 4F 9/2 →6H 15/2 (blue color) and 4F 9/2 →6H 13/2 (yellow color) with an excitation of 330 nm have been recorded. A series of considerable physical properties (oscillator strengths, refractive index, ions concentration, polaron radius) was calculated for each dopant concentration.

  4. Judd-Ofelt analysis of Sm3+ doped alkali borate glasses for optoelectronic applications

    Science.gov (United States)

    Nagaraj, R.; Vijayakumar, R.; Marimuthu, K.

    2017-05-01

    A new series of Sm3+ doped Alkali borate glasses have been prepared following the conventional melt quenching technique. The optical properties of the prepared glasses were explored through absorption, luminescence and decay measurements. The Judd-Ofelt (JO) intensity parameters Ωλ (λ=2, 4 and 6) were evaluated from the absorption spectra to examine the symmetry of the ligand environment around Sm3+ ions site. By using the JO parameters and refractive indices of the studied glasses, radiative parameters such as transition probability (A), branching ratios (βR), stimulated emission cross-section (σPE ) and radiative lifetime (τR) have been determined from the emission spectra following the JO theory. The excited state lifetime and the quantum efficiency of the Sm3+ doped title glasses pertaining to the 4G5/2 excited level have been determined through lifetime measurements and the results were discussed and reported.

  5. Optical characterization of zinc lithium bismuth borate glasses doped with Tb3+ for novel applications

    Science.gov (United States)

    Mallikarjuna, K.; Reddy, M. Bhushana; Moulika, G.; Reddy, B. Naveen Kumar; Ramanaiah, R.; Dhoble, S. J.; Reddy, B. Sudhakar

    2017-05-01

    Rare-earth (Tb3+) ions doped zinc lithium bismuth borate (ZLiBiB) glasses have been prepared by melt quenching method. From the FTIR spectrum, the functional groups have been identified. From the measurements of X-ray diffraction (XRD), differential scanning calorimeter (DSC) profiles of these glasses have been carried out. In case of Tb3+:ZLiBiB glasses emission transitions such as 5D4→ 7F6 (489 nm), 5D4→ 7F5 (545 nm), 5D4→ 7F4 (584 nm) and 5D4→ 7F3 (622 nm) have been identified. Among these, the transition at 542 nm has shown a bright green emission. The emission mechanism of Tb3+ doped ZLiBiB glasses has been explained in terms of energy level diagram.

  6. Floppy mode degeneracy and decoupling of constraint predictions in supercooled borate and silicate liquids

    Directory of Open Access Journals (Sweden)

    Bruno ePoletto Rodrigues

    2015-01-01

    Full Text Available The theory of temperature-dependent topological constraints has been used to successfully explain the compositional dependence of glass properties for oxide and non-oxide compositions. It relates the number of topological degrees of freedom with the glass transition temperature through the configurational entropy of the system. Based on this, we estimated the number of degrees of freedom directly from viscosity measurements of binary alkali borate and silicate glasses. Both approaches exhibit a strong decoupling, which we suggest can be traced to the presence of medium- and long-range constraints that are not taken into account by bond constraint counting. The observed variation of the energy barrier for structural rearrangement and floppy mode degeneracy also corroborate our interpretation. We provide evidence that the degeneracy of floppy modes changes with chemical composition and that the parameter K(x of the MYEGA viscosity equation could be used to assess changes in the medium-range order.

  7. Sensitivity of novel silicate and borate-based glass structures onin vitrobioactivity and degradation behaviour.

    Science.gov (United States)

    Mancuso, Elena; Bretcanu, Oana; Marshall, Martyn; Dalgarno, Kenneth W

    2017-10-15

    Three novel glass compositions, identified as NCL2 (SiO 2 -based), NCL4 (B 2 O 3 -based) and NCL7 (SiO 2 -based), along with apatite-wollastonite (AW) were processed to form sintered dense pellets, and subsequently evaluated for their in vitro bioactive potential, resulting physico-chemical properties and degradation rate. Microstructural analysis showed the carbonated hydroxyapatite (HCA) precipitate morphology following SBF testing to be composition-dependent. AW and the NCL7 formulation exhibited greater HCA precursor formation than the NCL2 and NCL4-derived pellets. Moreover, the NCL4 borate-based samples showed the highest biodegradation rate; with silicate-derived structures displaying the lowest weight loss after SBF immersion. The results of this study suggested that glass composition has significant influence on apatite-forming ability and also degradation rate, indicating the possibility to customise the properties of this class of materials towards the bone repair and regeneration process.

  8. Combination of platelet-rich plasma with degradable bioactive borate glass for segmental bone defect repair.

    Science.gov (United States)

    Zhang, Ya-Dong; Wang, Gang; Sun, Yan; Zhang, Chang-Qing

    2011-02-01

    Porous scaffold biomaterials may offer a clinical alternative to bone grafts; however, scaffolds alone are typically insufficient to heal large bone defects. Numerous studies have demonstrated that osteoinductive growth factor significantly improves bone repair. In this study, a strategy combining degradable bioactive borate glass (BG) scaffolds with platelet-rich plasma (PRP) was tested. The bone defect was filled with BG alone, BG combined with autologous PRP or left empty. Bone formation was analyzed at 4, 8 and 12 weeks using both histology and radiology. The PRP treated group yielded better bone formation than the pure BG scaffold as determined by both histology and microcomputer tomography after 12 weeks. In conclusion, PRP improved bone healing in a diaphyseal rabbit model on BG. The combination of PRP and BG may be an effective approach to repair critical defects.

  9. Spectroscopic and nonlinear optical studies of pure and Nd-doped lanthanum strontium borate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Harde, G. B. [Department of Physics, Shri R. R. Lahoti Science College, Morshi, Maharashtra, India-444905 (India); Department of Physics, Sant Gadge Baba Amravati University, Amravati, Maharashtra, India-444602 (India); Muley, G. G., E-mail: gajananggm@yahoo.co.in [Department of Physics, Sant Gadge Baba Amravati University, Amravati, Maharashtra, India-444602 (India)

    2016-05-06

    Borate glasses of the system xNd{sub 2}O{sub 3}-(1-x) La{sub 2}O{sub 3}-SrCO{sub 3}-10H{sub 3}BO{sub 3} (with x = 0 and 0.05) were prepared by using a convectional melt quenching technique. The amorphous nature of the quenched glasses has been confirmed by powder X-ray diffraction analysis. In order to study the spectroscopic and nonlinear optical properties of fabricated glasses, ultraviolet-visible transmission spectroscopy and open aperture z-scan measurements have been employed. In Nd doped glasses, the transition {sup 4}I{sub 9/2} → {sup 4}G{sub 5/2} + {sup 2}G{sub 7/2} has found more prominent than the other transitions. Optical band gap energies of glasses have been determined and found less for Nd doped glass.

  10. Silicate and borate glasses as composite fillers: a bioactivity and biocompatibility study.

    Science.gov (United States)

    Lopes, P P; Ferreira, B J M Leite; Gomes, P S; Correia, R N; Fernandes, M H; Fernandes, M H V

    2011-06-01

    Composites filled with a silicate glass (CSi) and a new borate glass (CB) were developed and compared in terms of their in vitro behaviour both in acellular and cellular media. Acellular tests were carried out in SBF and the composites were characterized by SEM-EDS, XRD and ICP. Biocompatibility studies were investigated by in vitro cell culture with MG-63 osteoblast-like and human bone marrow cells. The growth of spherical calcium phosphate aggregates was observed in acellular medium on all composite surfaces indicating that these materials became potentially bioactive. The biological assessment resulted in a dissimilar behavior of the composites. The CSi demonstrated an inductive effect on the proliferation of cells. The cells showed a normal morphology and high growth rate when compared to standard culture plates. Contrarily, inhibition of cell proliferation occurred in the CB probably due to its high degradation rate, leading to high B and Mg ionic concentration in the cell culture medium.

  11. Experimental and theoretical studies of the structure of tellurate-borate glasses network.

    Science.gov (United States)

    Rada, Simona; Culea, Eugen; Neumann, Manfred

    2010-08-01

    The structural properties of the xTeO(2) x (1-x)B(2)O(3) glasses (x = 0.6; 0.7) were investigated by FT-IR spectroscopy. From the analysis of the FTIR spectra, it is reasonable to assume that by the increasing of boron ions content, the tetrahedral [BO(4)] units are gradually replaced by the trigonal [BO(3)] units. The increase in the number of non-bridging oxygen atoms would decrease the connectivity of the glass network and will yield the depolymerization of the borate chains. The molecular structure and vibrational frequencies of the proposed structural models have been studied by exploring the density functional theory (DFT) calculations. The FTIR spectra of the xTeO(2) x (1-x)B(2)O(3) vitreous systems were compared with the calculated spectrum. This procedure allowed us to assign most of the observed IR bands.

  12. Elution characteristics of teicoplanin-loaded biodegradable borate glass/chitosan composite.

    Science.gov (United States)

    Jia, Wei-Tao; Zhang, Xin; Zhang, Chang-Qing; Liu, Xin; Huang, Wen-Hai; Rahaman, Mohamed N; Day, Delbert E

    2010-03-15

    Local antibiotic delivery system has an advantage over systemic antibiotic for osteomyelitis treatment due to the delivery of high local antibiotic concentration while avoiding potential systemic toxicity. Composite biomaterials with multifunctional roles, consisting of a controlled antibiotic release, a mechanical (load-bearing) function, and the ability to promote bone regeneration, gradually become the most active area of investigation and development of local antibiotic delivery vehicles. In the present study, a composite of borate glass and chitosan (designated BG/C) was developed as teicoplanin delivery vehicle. The in vitro elution kinetics and antibacterial activity of teicoplanin released from BG/C composite as a function of immersion time were determined. Moreover, the pH changes of eluents and the bioactivity of the composite were characterized using scanning electron microscopy coupled with energy-dispersive spectroscopy and X-ray diffraction analysis. 2009 Elsevier B.V. All rights reserved.

  13. Effect of R(3+) ions on the structure and properties of lanthanum borate glasses

    Science.gov (United States)

    Chakraborty, I. N.; Day, D. E.

    1985-01-01

    The present investigation of glass formation in the (mole percent) systems 25La2O3 (x)R2O3 (75-x)B2O3, where R = Al, Ga, and (25-x)La2O3 (x)Ln2O3 75B2O3, where Ln = Gd, Er, Y, notes that up to 25 mol pct Al2O3 or Ga2O3 can be substituted for B2O3, while no more than about 5 mol pct Ln2O3, substituted for La2O3, caused macro-phase separation. The substitution of either R2O3 or Ln2O3 in the lanthanum borate system changes the separation distance between adjacent B3O6 chains. The effect of this structural change on the molar volume, transformation temperature, thermal expansion coefficient, and transformation-range viscosity is discussed.

  14. [Injectable borate glass/chitosan composite as drug carrier for treatment of chronic osteomyelitis].

    Science.gov (United States)

    Zhao, Cunju; Wang, Xinfu; Zhang, Changqing; Cui, Xu; Jia, Weitao; Huang, Wenchan

    2012-06-01

    To evaluate the characterization, biocompatibility in vitro and in vivo, and antimicrobial activity of an injectable vancomycin-loaded borate glass/chitosan composite (VBC) so as to lay the foundation for its further clinical application. The solid phase of VBC was constituted by borate glass and vancomycin, liquid phase was a mixture of chitosan, citric acid, and glucose with the proportion of 1 : 10 : 20. Solid phase and liquid phase was mixed with the ratio of 2 : 1. Vancomycin-loaded calcium sulfate (VCS) was produced by the same method using calcium sulfate instead of borate glass and saline instead of chitosan, as control. High performance liquid chromatography was applied to detect the release rate of antibiotics from VBC and VCS, and minimum inhibitory concentration (MIC) was tested by using an antibiotic tube dilution method. The structure of the VBC and VCS specimens before and 2, 4, 8, 16, and 40 days after immersion in D-Hank's was examined by scanning electron microscopy, and the phase composition of VBC was analysed by X-ray diffraction after soaked for 40 days. Thirty-three healthy adult New Zealand white rabbits (weighing, 2.25-3.10 kg; male or female) were used to establish the osteomyelitis models according to Norden method. After 4 weeks, the models of osteomyelitis were successfully established in 28 rabbits, and they were randomly divided into 4 groups (groups A, B, C, and D). In group A (n=8), simple debridement was performed; in groups B and C (n=8), defect was treated by injecting VCS or VBC after debridement; and in group D (n=4), no treatment was given. The effectiveness of treatment was assessed using radiological and histological techniques after 2 months. The releases of vancomycin from VBC lasted for 30 days; the release rate of vancomycin reached 75% at the first 8 days, then could reached more than 90%. The releases of vancomycin from VCS lasted only for 16 days. The MIC of VBC and VCS were both 2 microg/mL. The VCS had a smooth

  15. Emission properties of Ce3+ centers in barium borate glasses prepared from different precursor materials

    Science.gov (United States)

    Torimoto, Aya; Masai, Hirokazu; Okada, Go; Kawaguchi, Noriaki; Yanagida, Takayuki; Ohkubo, Takahiro

    2017-10-01

    The photoluminescence (PL) and X-ray induced luminescence properties of Ce-doped barium borate glasses prepared from different precursor materials have been investigated. Oxidation of Ce3+ takes place during the melting process performed using a pre-vitrified non-doped glass. Residual groups originated from the precursor materials, such as fluorine atoms and OH groups, are found to affect the optical and emission properties of the glasses. Moreover, both the PL and the X-ray induced luminescence properties of the glasses depend on the precursor materials used for their synthesis. Based on a thorough analysis of the emission properties, we conclude that the best synthesis conditions involve melting a batch containing Ce(CH3COO)3·H2O, BaCO3, and B2O3 in Ar atmosphere.

  16. Optically stimulated luminescence of borate glasses containing magnesia, quicklime, lithium and potassium carbonates

    Science.gov (United States)

    Valença, J. V. B.; Silveira, I. S.; Silva, A. C. A.; Dantas, N. O.; Antonio, P. L.; Caldas, L. V. E.; d'Errico, F.; Souza, S. O.

    2017-11-01

    The OSL characteristics of three different borate glass matrices containing magnesia (LMB), quicklime (LCB) or potassium carbonate (LKB) were examined. Five different formulations for each composition were produced using a melt-quenching method and analyzed in terms of both dose-response curves and OSL shape decay. The samples were irradiated using a 90Sr/90Y beta source with doses up to 30 Gy. Dose-response curves were plotted using the initial OSL intensity as the chosen parameter. The OSL analysis showed that LKB glasses are the most sensitive to beta irradiation. For the most sensitive LKB composition, the irradiation process was also done using a 60Co gamma source in a dose range from 200 to 800 Gy. In all cases, no saturation was observed. A fitting process using a three-term exponential function was performed for the most sensitive formulations of each composition, which suggested a similar behavior in the OSL decay.

  17. Further work on sodium borates as sacrificial materials for a core-catcher

    International Nuclear Information System (INIS)

    Dalle Donne, M.; Dorner, S.; Roth, A.; Werle, H.

    1982-01-01

    Sodium borates are suitable low melting point sacrificial materials for a core-catcher of a fast reactor. Concept, design and initial development work have been described previously. Here we report on the measurements of density, volumetric thermal expansion coefficients and viscosity of borax and sodium metaborate, pure and with various percentages of dissolved UO 2 . The density of these molten salts was measured with the buoyancy method in the temperature range 850 - 1300 0 C, while the viscosity was measured in the temperature range 700 - 1250 0 C with a Haake viscosity balance. Simulation experiments with low melting point materials were performed to investigate the ratio of the downward to sideward melt velocity. The results of these experiments show that this ratio is equal to 0.34 for a solid to liquid density ratio rho = 1.66. For the real borax core-catcher rho = 4 and this would correspond to a velocity ratio of about one

  18. Flux Growth and Crystal Structure Refinement of Calcite Type Borate GaBO3

    Directory of Open Access Journals (Sweden)

    Shichao Wang

    2015-05-01

    Full Text Available A single crystal of gallium borate, GaBO3, 4 × 4 × 0.2 mm3 in size has been grown by spontaneous crystallization with a molten flux based on a Bi2O3-3B2O3 solvent. From single crystal X-ray diffraction measurement, GaBO3 was found to crystallize in the trigonal calcite type, space group R-3c, with cell dimensions a = 4.56590(10 and c = 14.1764(4 Å, Z = 6. Layers of distorted [GaO6] octahedra are interleaved by layers of triangular planar [BO3] unites. The transmission spectrum on a single crystal indicated that the band gap of GaBO3 is 3.62 eV.

  19. Fate and behavior of an organo-borate in the soil-plant system

    International Nuclear Information System (INIS)

    Adriano, D.C.; Mills, G.L.; Afre, J.L.; Hart, R.J.

    1984-01-01

    An organo-borate, sodium tetraphenylboron (NaTPB), is used to precipitate radiocesium in high level nuclear wastes in conjunction with the 'glassification' of these wastes for long-term storage. Because of the possibility of this compound interacting with the environment through land application of the waste supernate or ground burial of the waste 'saltblocks', studies were undertaken to evaluate the environmental chemistry of this compound. Results indicate that the parent compound, NaTPB, is unstable in the soil-plant system, yielding two primary degradation products, biphenyl and diphenylborinic acid. Plant growth and B uptake data further indicate that the growth of plants was more deleteriously affected by NaTPB soil treatment than by comparable soil treatment with boric acid, in spite of the much greater uptake of B from boric acid. This can be attributed to the hypothesized aggravating effect of biphenyl on plant growth. (author)

  20. Electrochemistry in molten borates (Na2B4O7). Electroanalytical study of oxidoreducing systems

    International Nuclear Information System (INIS)

    Gregori de Pinochet, Ida de

    1978-01-01

    The results of a study developing suitable electroanalytical means of investigation such as linear sweep voltametry and chronopotentiometry in molten borates are described. It has been shown that the reduction of U (VI) to U (V) proceeds reversibly at a platinum electrode. The diffusion coefficient for the U (VI) species at 800 0 C and the activation energy of diffusion are respectively 4 10 -7 cm 2 s -1 and (34,8+-0,8) k cal mol -1 . UO 2 is an insoluble oxide in this fused salt. Electrochemical studies of As (V) and Cu (II) show a two step reduction process at a platinum electrode. According to the solvent system definitions, the 'acid-base' equilibrium B 4 O 7 2- reversible 2 BO 2 - + B 2 O 3 is characterised at 820 0 C by the constant Ksub(D)=10sup(0,4)molsup(3)kgsup(-3) estimated by potentiometric study at a boron electrode [fr

  1. Synthesis, structural characterization and scalable preparation of new amino-zinc borates

    Energy Technology Data Exchange (ETDEWEB)

    Imer, M. R. [Departamento Estrella Campos; Facultad de Química; Universidad de la República; Montevideo; Uruguay; González, M. [Departamento Estrella Campos; Facultad de Química; Universidad de la República; Montevideo; Uruguay; Veiga, N. [Departamento Estrella Campos; Facultad de Química; Universidad de la República; Montevideo; Uruguay; Kremer, C. [Departamento Estrella Campos; Facultad de Química; Universidad de la República; Montevideo; Uruguay; Suescun, L. [Laboratorio de Cristalografía; Química del Estado Sólido y Materiales; Cátedra de Física; DETEMA; Facultad de Química; Arizaga, L. [Departamento Estrella Campos; Facultad de Química; Universidad de la República; Montevideo; Uruguay

    2017-01-01

    Zinc borates are important materials. We report the preparation of three novel ones: [Zn(NH3)3B4O5(OH)4]·H2O (ZB1), Zn3(H2B3O7)2·2NH3·4H2O (ZB2), and [Zn(NH3)4][B4O5(OH)4]·4H2O (ZB3).

  2. The minimum additive waste stabilization (MAWS) for vitrification of borate waste from NPP in china

    International Nuclear Information System (INIS)

    Sheng, Jiawei; Luo, Shanggeng; Tang, Baolong

    1997-01-01

    Vitrification is a technically sound alternative to cementation with larger waste loading and better chemical durability. The MAWS is a more effective vitrification approach which provides an environmentally sound alternative for large amount of low level radioactive waste that exists in NPP. The main object of this work is to search a suitable borosilicate glass matrix which could incorporate relatively high quantity of B and Na. All of B and Na in glass are coming from waste and there isn't any additives of B and Na. It is found that glasses with borate waste of 45-52wt% generally have good chemical durability. The selected waste glass formulation named SL-1 can corporate 45wt% waste oxides, and the melt temperature is lower (1000 .deg.) with less corrosion to melter. The viscosity at 1000 .deg. is about 5.0 Pa.s, which is a suitable value for processing. SL-1 glass also has good chemical durability

  3. Effect of beam oscillation on borated stainless steel electron beam welds

    Energy Technology Data Exchange (ETDEWEB)

    RajaKumar, Guttikonda [Tagore Engineering College, Chennai (India). Dept. of Mechanical Engineering; Ram, G.D. Janaki [Indian Institute of Technology (IIT), Chennai (India). Dept. of Metallurgical and Materials Engineering; Rao, S.R. Koteswara [SSN College of Engineering, Chennai (India). Mechanical Engineering

    2015-07-01

    Borated stainless steels are used in nuclear power plants to control neutron criticality in reactors as control rods, shielding material, spent fuel storage racks and transportation casks. In this study, bead on plate welds were made using gas tungsten arc welding (GTAW) and electron beam welding (EBW) processes. Electron beam welds made using beam oscillation technique exhibited higher tensile strength values compared to that of GTA welds. Electron beam welds were found to show fine dendritic microstructure while GTA welds exhibited larger dendrites. While both processes produced defect free welds, GTA welds are marked by partially melted zone (PMZ) where the hardness is low. EBW obviate the PMZ failure due to low heat input and in case of high heat input GTA welding process failure occurs in the PMZ.

  4. Chemical composition and mineralogy of borate from Rio Grande deposit, Uyuni (Bolivia) as raw materials for industrial applications

    Science.gov (United States)

    Guillen Vargas, Julio; Arancibia, Jony Roger Hans; Alfonso, Pura; Garcia-Valles, Maite; Parcerisa, David; Martinez, Salvador

    2014-05-01

    Bolivia has large tailings as a result of the historic and present-day Sn mining activity developed extensively in that country. Tailings produced in these mining activities have an appropriate composition to reprocess them and make silicate glass and glass-ceramics, obtaining the valorization of wastes and reducing the visual and chemical impact. Reprocessing the wastes to make glass and glass-ceramics prevents the leaching of heavy metals from those wastes because they are retained in the structure of the glass. Furthermore, an option to increase the economic value of these glasses is the introduction of boron and other additives to produce borosilicate glass. In this study a characterization of the Rio Grande borate deposit for its use in the manufacture of borosilicate glass is presented. Mineralogy was determined by X-ray diffraction (XRD), and Fourier transforms infrared spectroscopy (FTIR); textures were observed by scanning electron microscopy (SEM) and chemical composition was determined by inductively coupled plasma mass spectrometry (ICP-MS). The Rio Grande borate deposit is located in an area of about 50 km2 close to the south of the Salar of Uyuni, in the Río Grande de Lípez Delta. Borates occur in the contact between fluvio-deltaic and lacustrine sediments from water raising the surface by capillarity. The borates crop out in an extent area but towards the west they are covered by fluvio-deltaic sediments, which can be up to 2 m thick. These borates occur as lenses 50-100 m in diameter and layers up to 1 m thick. They usually form brittle nodules with a cotton-ball texture. Chemical composition of the Rio Grande borates is CaO, 11.82-13.83 wt%; Na2O, 13.50-19.35 wt%; K2O, 0.05- 1.04 wt%; MgO, 0.42-1.46 wt%; B2O3, 36.21-42.60 wt%; SiO2, up to 0.53 wt% and SO2, up to 0.60 wt%. Trace elements are low: Sr content is between 151-786 ppm, Al 12-676 ppm, Mn between 1-17 ppm, As 2-10 ppm and Fe between 9-376 ppm. The most abundant borate mineral in this

  5. Moessbauer effect and infrared study of some borate glass containing Mn and Fe oxides

    International Nuclear Information System (INIS)

    Gabr, M.

    2005-01-01

    Lithium borate glasses containing transition metals appeared now of very high technological and scientific interest. Therefore some lithium borate glasses containing mixed transition metal ions (manganese and iron) were investigated. The glass batches were melted at 1250 degree C for three hours and annealed at 350 degree C -over night- to obtain strain free glasses. Moessbauer Effect spectroscopy and Infrared analysis were employed to investigate the structural changes due to the change of their batches composition. Differential thermal analysis, magnetic susceptibility, density and molar volume measurements were also performed to study the effect of changing both manganese and iron oxides at the expense of boron oxide on these properties. Infrared analysis indicated the presence of different structural groups such as BO 3 , BO 4 , FeO 4 and MnO 6 as well as different vibrations indicated the presence of various bonds in the glass network. The values of the characteristic temperatures (T g , T c and T m ) showed gradual increase except those of the last sample where they showed a decrease. The mid sample showed the lowest stability value. It was found that the molar volume showed its highest value at R=0.33 [where R is the ratio of glass network modifier to the glass network former]. After that it showed gradual linear decrease. The magnetic susceptibility measurements showed approximately stable value between R=0.29 and 0.33, then it increased up to R=0.38, and after that, it decreased up to R= 0.43. The obtained magnetic susceptibility values indicated that all these glasses are paramagnetic. The obtained Moessbauer spectra and the calculated parameters confirmed that iron ions participated in the glass network as network former cations. It confirmed also that all glasses reflect paramagnetic character. The observed structural change were explained and correlated with the change of the measured physical properties

  6. In vivo and in vitro studies of borate based glass micro-fibers for dermal repairing.

    Science.gov (United States)

    Zhou, Jie; Wang, Hui; Zhao, Shichang; Zhou, Nai; Li, Le; Huang, Wenhai; Wang, Deping; Zhang, Changqing

    2016-03-01

    Full-thickness skin defects represent urgent clinical problem nowadays. Wound dressing materials are hotly needed to induce dermal reconstruction or to treat serious skin defects. In this study, the borate bioactive glass (BG) micro-fibers were fabricated and compared with the traditional material 45S5 Bioglass(®) (SiG) micro-fibers. The morphology, biodegradation and bioactivity of BG and SiG micro-fibers were investigated in vitro. The wound size reduction and angiogenic effects of BG and SiG micro-fibers were evaluated by the rat full-thickness skin defect model and Microfil technique in vivo. Results indicated that the BG micro-fibers showed thinner fiber diameter (1 μm) and better bioactivity than the SiG micro-fibers did. The ionic extracts of BG and SiG micro-fibers were not toxic to human umbilical vein endothelial cells (HUVECs). In vivo, the BG micro-fiber wound dressings obviously enhanced the formation of blood vessel, and resulted in a much faster wound size reduction than the SiG micro-fibers, or than the control groups, after 9 days application. The good skin defect reconstruction ability of BG micro-fibers contributed to the B element in the composition, which results in the better bioactivity and angiogenesis. As shown above, the novel bioactive borate glass micro-fibers are expected to provide a promising therapeutic alternative for dermal reconstruction or skin defect repair. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Electrical properties of fast ion conducting silver based borate glasses: Application in solid battery

    International Nuclear Information System (INIS)

    Masoud, Emad M.; Khairy, M.; Mousa, M.A.

    2013-01-01

    Graphical abstract: -- Highlights: •AgI dopant created more opened borate network structure. •Dielectric constant and loss values increased with AgI concentration. •AgI dopant enhanced both ion migration and orientation. •0.6 AgI–0.27 Ag 2 O–0.13 B 2 O 3 showed the highest DC-conductivity at room temperature. •It showed also good life time as a solid electrolyte in solid battery at room temperature. -- Abstract: The electrical properties of the ternary ionic conducting glass system xAgI–(1 – x)[0.67Ag 2 O–0.33B 2 O 3 ], where x = 0.4 , 0.5, 0.6, 0.7 and 0.8, were studied for emphasizing the influence of silver iodide concentration on the transport properties in the based borate glasses. The glasses were prepared by melt quenching technique and characterized using X-ray diffraction (XRD), FT-IR spectra and differential thermal analysis (DTA). XRD confirmed a glassy nature for all investigated compositions. Electrical conductivity (σ), dielectric constant (ε′), dielectric loss (ε ″ ) and impedance spectra (Z′–Z′′) were studied for all samples at a frequency range of 0–10 6 Hz and over a temperature range of 303–413 K. Changes of conductivity and dielectric properties with composition, temperature and frequency were analyzed and discussed. A silver iodine battery using glassy electrolyte sample with the highest ionic conductivity (x = 0.6) was studied

  8. In situ hydroxyapatite nanofiber growth on calcium borate silicate ceramics in SBF and its structural characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Pu, Yinfu; Huang, Yanlin; Qi, Shuyun [College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123 (China); Chen, Cuili [Department of Physics and Interdisciplinary Program of Biomedical, Mechanical & Electrical Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of); Seo, Hyo Jin, E-mail: hjseo@pknu.ac.kr [Department of Physics and Interdisciplinary Program of Biomedical, Mechanical & Electrical Engineering, Pukyong National University, Busan 608-737 (Korea, Republic of)

    2015-10-01

    A novel calcium silicate borate Ca{sub 11}Si{sub 4}B{sub 2}O{sub 22} ceramic was firstly prepared by the conventional solid-state reaction. In vitro hydroxyapatite mineralization was investigated by soaking the ceramics in simulated body fluid (SBF) solutions at body temperature (37 °C) for various time periods. Scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD) measurements were applied to investigate the samples before and after the immersion of ceramics in SBF solution. The elemental compositions of a hydroxyapatite layer on the ceramics during the mineralization were confirmed by X-ray energy-dispersive spectra (EDS). Meanwhile, the bending strength and elastic modulus of Ca{sub 11}Si{sub 4}B{sub 2}O{sub 22} ceramics were also measured, which indicate that the biomaterials based on Ca{sub 11}Si{sub 4}B{sub 2}O{sub 22} ceramics possess bioactivity and might be a potential candidate as biomaterials for hard tissue repair. The bioactive mineralization ability was evaluated on the base of its crystal structural characteristics, i.e., silanol (Si–OH) and B–OH groups can be easily induced on the surface of Ca{sub 11}Si{sub 4}B{sub 2}O{sub 22} ceramics soaked in SBF solutions. - Highlights: • Calcium silicate borate Ca{sub 11}Si{sub 4}B{sub 2}O{sub 22} ceramics were developed as a new biomaterial. • Ca{sub 11}Si{sub 4}B{sub 2}O{sub 22} shows a superior in vitro bioactivity by inducing bone-like apatite. • Ca{sub 11}Si{sub 4}B{sub 2}O{sub 22} has good mechanical properties as potential candidate biomaterials. • The structure with SiO{sub 4} and BO{sub 3} groups is favorable for hydroxyapatite formation.

  9. Thermoluminescence characteristics of Cu2O doped Calcium Lithium borate glass irradiated with the cobalt-60 gamma rays

    International Nuclear Information System (INIS)

    Rammadhan, Ismail; Taha, Saddon; Wagiran, H.

    2017-01-01

    The aim of this study is to prepare and investigate the thermoluminescence characteristics for the un-doped and Cu 2 O doped calcium lithium borate glass upon adding various Cu 2 O concentrations of 0.005% to 0.1 mol%. The glasses were prepared by melt quenching method and irradiated with 60 CO gamma-ray having different doses in the range of (0.5–4) Gy, (5–10) Gy, and (20–100) Gy. The amorphous phases were identified for optimization glass samples, effect of heating rate, glowing curves, linearity, sensitivity, fading, reproducibility of response and minimum detectable dose are also studied. The TL sample with 0.02 mol% Cu 2 O concentration has higher response compared to the other samples concentration for a delivered dose of 50 Gy, The recorded glow curves consist a dominant peak at 187 °C for a heating rate of 5 °C s −1 . However, the value of effective atomic number Z eff is 8.84 for 0.02Cu 2 O doped which are near to the atomic number of soft tissue. - Highlights: •We have prepared and investigate the crystalline structure for the un-doped and Cu 2 O doped calcium lithium borate glass are carried out. •Investigate the amorphous structure of calcium lithium borate glass. •Determine the best setting of annealing temperature, annealing time and heating rate for Cu 2 O doped calcium lithium borate glass. •The doping effects of Cu 2 O on the thermoluminescence properties of calcium lithium borate glass subjected gamma radiations. •The new dosimeter showed simple glow curve with single prominent peak centred at 187 °C and linear dose–response range 0.5–100 Gy, good reproducibility, the fading of the signal is relatively slow. •Effective atomic number for Cu 2 O doped Calcium lithium borate close to the effective atomic number of soft tissue.

  10. The structures of two scorpionates: thallium tetrakis(3-phenyl-1H-pyrazol-1-yl)borate and potassium tetrakis(3-cyclopropyl-1H-pyrazol-1-yl)borate.

    Science.gov (United States)

    Infantes, Lourdes; Claramunt, Rosa M; Sanz, Dionisia; Alkorta, Ibon; Elguero, José

    2016-11-01

    The introduction of poly(1H-pyrazolyl)borate anions, better known as scorpionates, as negatively charged ligands for a great diversity of metal cations has had a tremendous influence in coordination chemistry. The structures of two salts of tetrakispyrazolylborate, namely [tetrakis(3-phenyl-1H-pyrazol-1-yl)borato]thallium(I), [Tl(C 36 H 28 BN 8 )], and catena-poly[potassium-[μ 2 -tetrakis(3-cyclopropyl-1H-pyrazol-1-yl)borato

  11. Bis(fluoromalonato)borate (BFMB) anion based ionic liquid as an additive for lithium-ion battery electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xiao-Guang [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciencese Division; Liao, Chen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciencese Division; Baggetto, Loïc [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Guo, Bingkun [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciencese Division; Unocic, Raymond R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science; Veith, Gabriel M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Dai, Sheng [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciencese Division; Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemistry

    2014-02-21

    Propylene carbonate (PC) is a good solvent for lithium ion battery applications due to its low melting point and high dielectric constant. But, PC is easily intercalated into graphite causing it to exfoliate, killing its electrochemical performance. We report on the synthesis of a new ionic liquid electrolyte based on partially fluorinated borate anion, 1-butyl-1,2-dimethylimidazolium bis(fluoromalonato)borate (BDMIm.BFMB), which can be used as an additive in 1 M LiPF6/PC electrolyte to suppress graphite exfoliation and improve cycling performance. Additionally, both PC and BDMIm.BFMB can be used synergistically as additive to 1.0M LiPF6/methyl isopropyl sulfone (MIPS) to dramatically improve its cycling performance. It is also found that the chemistry nature of the ionic liquids has dramatic effect on their role as additive in PC based electrolyte.

  12. Teicoplanin-loaded borate bioactive glass implants for treating chronic bone infection in a rabbit tibia osteomyelitis model.

    Science.gov (United States)

    Zhang, Xin; Jia, Weitao; Gu, Yifei; Xiao, Wei; Liu, Xin; Wang, Deping; Zhang, Changqing; Huang, Wenhai; Rahaman, Mohamed N; Day, Delbert E; Zhou, Nai

    2010-08-01

    The treatment of chronic osteomyelitis (bone infection) remains a clinical challenge. In this work, pellets composed of a chitosan-bonded mixture of borate bioactive glass particles (glass converted to hydroxyapatite (HA) within 7 days, eventually forming a porous HA structure. Implantation of the teicoplanin-loaded pellets in a rabbit tibia osteomyelitis model resulted in the detection of teicoplanin in the blood for about 9 days. The implants converted to a bone-like HA graft, and supported the ingrowth of new bone into the tibia defects within 12 weeks of implantation. Microbiological, histological and scanning electron microscopy techniques showed that the implants provided a cure for the bone infection. The results indicate that the teicoplanin-loaded borate bioactive glass implant, combining sustained drug release with the ability to support new bone ingrowth, could provide a method for treating chronic osteomyelitis. Copyright 2010 Elsevier Ltd. All rights reserved.

  13. Amorphous Nickel-Cobalt-Borate Nanosheet Arrays for Efficient and Durable Water Oxidation Electrocatalysis under Near-Neutral Conditions.

    Science.gov (United States)

    Chen, Lanlan; Ren, Xiang; Teng, Wanqing; Shi, Pengfei

    2017-07-21

    Electrolytic hydrogen generation needs earth-abundant oxygen evolution reaction electrocatalysts that perform efficiently at mild pH. Here, the development of amorphous nickel-cobalt-borate nanosheet arrays on macroporous nickel foam (NiCo-Bi/NF) as a 3D catalyst electrode for high-performance water oxidation in near-neutral media is reported. To drive a current density of 10 mA cm -2 , the resulting NiCo-Bi/NF demands an overpotential of only 430 mV in 0.1 m potassium borate (K-Bi, pH 9.2). Moreover, it also shows long-term electrochemical durability with maintenance of catalytic activity for 20 h, achieving a high turnover frequency of 0.21 s -1 at an overpotential of 550 mV. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. EPR of SeO2- and SeO3- radicals in alkaline borate glasses with 77Se isotope

    International Nuclear Information System (INIS)

    Galimov, D.G.; Tarzimanov, K.D.

    1977-01-01

    Alkaline borate glasses with 77 Se were investigated in order to establish the nature of selenium compounds and radicals in glasses. The relationship between alkali ions and the oxygen radical of selenium was determined by decoding the hyperfine structure of the alkaline borate glass EPR spectra obtained before and after γ-irradiation. The irradiated and non-irradiated glasses were characterized by hyperfine splitting of the EPR lines from the α- and β centres. Moreover, the irradiated samples were noted to have a line doublet (signal phi). With intenser reduction conditions of glass fusion, the intensities of α, β, and phi signals were noted to decline. This confirmes the suggestion that these centres were caused by oxygen compouds. The authors concluded that α and β signals were due to the paramagnetic centres of SeO 2 - and [SeO 2 - ]R + , and phi signal to the SeO 3 - radicals

  15. New type of complex alkali and alkaline earth metal borates with isolated (B12O24)12) anionic group.

    Science.gov (United States)

    Wu, Hongping; Yu, Hongwei; Pan, Shilie; Jiao, Anqing; Han, Jian; Wu, Kui; Han, Shujuan; Li, Hongyi

    2014-03-28

    Compounds with isolated anionic groups often exhibit special linear and nonlinear optical properties and possess potential applications such as birefringence, second harmonic generation and stimulated Raman scattering crystals. In this paper, two new alkali and alkaline earth mixed-metal borates, Li3KB4O8 and LiNa2Sr8B12O24F6Cl, with isolated (B12O24)(12-) anionic groups have been successfully synthesized by spontaneous crystallization. Their structures were determined by single crystal X-ray diffraction and they both crystallize in the same space group, R3[combining macron]. More interestingly, further structure comparison shows that the discovered anhydrous borates with the (B12O24)(12-) groups also crystallize in the same space group R3[combining macron], which is related with the local symmetry of the (B12O24)(12-) groups. These structural features suggest that the crystal structures of the family of compounds depend more on their anionic groups. In addition, the property characterizations of the two new borates were investigated by TG-DSC, IR and UV-vis-NIR diffuse reflectance.

  16. Poly(vinyl alcohol)-borate hydro/cosolvent gels: viscoelastic properties, solubilizing power, and application to art conservation.

    Science.gov (United States)

    Carretti, Emiliano; Grassi, Scilla; Cossalter, Manuela; Natali, Irene; Caminati, Gabriella; Weiss, Richard G; Baglioni, Piero; Dei, Luigi

    2009-08-04

    We report the development of a new type of hydrogel in which a cosolvent has been added to the water component. The gel networks are based on the well-known poly(vinyl alcohol)-borate systems (PVA-borate). However, it is shown that the rheological and solubilizing properties of the hydrogels can be modified drastically by the addition of a cosolvent. The studies have focused on 1-propanol as the added liquid, although it is shown that others (propylene carbonate, 1-pentanol, cyclohexanone, and 2-butanol) are amenable to making modified hydrogels as well. In addition to the rheological measurements, the gels have been investigated by differential scanning calorimetry (free water index) and determination of their solubilizing power. Finally, the gels have been applied to clean and oxidized varnish (patina) from the surface of a XVI-XVII century oil-on-wood painting by Ludovico Cardi detto il Cigoli. The mode of cleaning by and removal of the PVA-borate water/1-propanol gel from the painted surface demonstrate several advantages over other gels used in art conservation.

  17. Social and political perceptions of the Borat phenomenon in Kazakhstan: evidence from a case study of university students

    Directory of Open Access Journals (Sweden)

    Donnacha Ó Beacháin

    2011-11-01

    Full Text Available This article begins by chronicling and evaluating the reaction of the government of Kazakhstan to Sacha Baron Cohen’s film Borat—Cultural Learnings of America for Make Benefit Glorious Nation of Kazakhstan. It then compares and contrasts the official government reaction with the expressed attitudes of local members of Kazakhstan’s young English-speaking elites. This study is based on the results of a survey of almost five hundred young university students conducted in March 2007 at the Kazakhstan Institute of Management, Economics and Strategic Research (KIMEP, the most prestigious university in the country. The sample gives a snapshot of those most likely to have been aware of Borat – the young, internet-savvy, educated urban elite – and inter alia provides insights into how respondents in Kazakhstan thought the movie impacted their country and would influence how they were treated abroad. The survey results suggest that while responses to Borat were heterogeneous, most students accepted that the choice of Kazakhstan as a target for satire was coincidental rather than conspiratorial. Despite official efforts to ban the movie, a majority of the respondents had seen the film and believed that the ban was a mistake. Also, while recognising that Borat would raise Kazakhstan’s profile in the world, respondents doubted it would increase knowledge, and some feared a change in their treatment when travelling abroad.

  18. Thermoluminescence Response of Copper-Doped Potassium Borate Glass Subjected to 6 Megavolt X-Ray Irradiation

    Science.gov (United States)

    Hossain, I.; Shekaili, N. K.; Wagiran, H.

    2015-03-01

    This study addresses the characteristics of Cu-doped and undoped potassium borate glass for use as ionizing radiation dosimeters by investigating and comparing the thermoluminescence responses, linearity, sensitivity and dose response s of the two types of glasses. A number of samples based on xK 2 CO 3 + (100 - x)H 3 BO 3 , where 10 ≤ x ≤ 30 mol.%, have been prepared using a melt quenching technique. The amorphous phases were identified using X-ray diffraction (XRD). The undoped potassium borate samples 20K 2 CO 3 + 80H 3 BO 3 (mol.%) and Cu-doped (0.5 mol.%) samples were placed in a solid phantom apparatus and irradiated with in X-ray tube under 6 MV accelerating voltage with doses ranging from 0.5 to 4.0 Gy. This beam was produced by the Primus MLC 3339 linear accelerator (LINAC) available at Hospital Sultan Ismail, Johor Bahru, Malaysia. The results clearly show the superiority of Cu-doped glass in terms of response and sensitivity to producing luminescence over undoped potassium borate glass. The sensitivity of Cu-doped glass is 6.75 times greater than that of undoped glass.

  19. Effect of 3d-transition metal doping on the shielding behavior of barium borate glasses: a spectroscopic study.

    Science.gov (United States)

    ElBatal, H A; Abdelghany, A M; Ghoneim, N A; ElBatal, F H

    2014-12-10

    UV-visible and FT infrared spectra were measured for prepared samples before and after gamma irradiation. Base undoped barium borate glass of the basic composition (BaO 40%-B2O3 60mol.%) reveals strong charge transfer UV absorption bands which are related to unavoidable trace iron impurities (Fe(3+)) within the chemical raw materials. 3d transition metal (TM)-doped glasses exhibit extra characteristic absorption bands due to each TM in its specific valence or coordinate state. The optical spectra show that TM ions favor generally the presence in the high valence or tetrahedral coordination state in barium borate host glass. Infrared absorption bands of all prepared glasses reveal the appearance of both triangular BO3 units and tetrahedral BO4 units within their characteristic vibrational modes and the TM-ions cause minor effects because of the low doping level introduced (0.2%). Gamma irradiation of the undoped barium borate glass increases the intensity of the UV absorption together with the generation of an induced broad visible band at about 580nm. These changes are correlated with suggested photochemical reactions of trace iron impurities together with the generation of positive hole center (BHC or OHC) within the visible region through generated electrons and positive holes during the irradiation process. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Luminescence investigations of rare earth doped lead-free borate glasses modified by MO (M = Ca, Sr, Ba)

    Energy Technology Data Exchange (ETDEWEB)

    Janek, Joanna, E-mail: janek.joanna@gmail.com; Sołtys, Marta; Żur, Lidia; Pietrasik, Ewa; Pisarska, Joanna; Pisarski, Wojciech A.

    2016-09-01

    Series of lead-free borate glasses with different oxide modifiers and lanthanide ions were prepared. The effect of oxide modifiers MO (M = Ca, Sr, Ba) on spectroscopic properties of trivalent Ln{sup 3+} (Ln = Eu, Er, Pr) were systematically investigated. Especially, the luminescence spectra of Ln{sup 3+}-doped lead-free borate glasses are presented and discussed in relation to the impact of selective components (CaO, SrO and BaO). Several spectroscopic parameters, such as the fluorescence intensity ratio R/O (Eu{sup 3+}) and measured luminescence lifetimes for the {sup 5}D{sub 0} (Eu{sup 3+}), {sup 4}I{sub 13/2} (Er{sup 3+}) and {sup 1}D{sub 2} (Pr{sup 3+}) excited states of lanthanide ions were analyzed in details. The research proved that spectroscopic properties of trivalent Ln{sup 3+} depend significantly on kind of presence oxide modifiers MO (M = Ca, Sr, Ba) in glass host matrices. - Highlights: • Luminescence of Ln{sup 3+}-doped borate glasses was presented and discussed. • Effect of glass modifiers on spectroscopic properties of rare earths was studied. • Measured luminescence lifetimes of Ln{sup 3+} (Ln = Eu, Er, Pr) were analyzed. • Luminescence intensity ratios R/O (Eu{sup 3+}) were determined.

  1. Investigation of Gamma and Neutron Shielding Parameters for Borate Glasses Containing NiO and PbO

    Directory of Open Access Journals (Sweden)

    Vishwanath P. Singh

    2014-01-01

    Full Text Available The mass attenuation coefficients, μ/ρ, half-value layer, HVL, tenth-value layer, TVL, effective atomic numbers, ZPIeff, and effective electron densities, Ne,eff, of borate glass sample systems of (100-x-y Na2B4O7 : xPbO : yNiO (where x and y=0, 2, 4, 6, 8, and 10 weight percentage containing PbO and NiO, with potential gamma ray and neutron shielding applications, have been investigated. The gamma ray interaction parameters, μ/ρ, HVL, TVL, ZPIeff, and Ne,eff, were computed for photon energy range 1 keV–100 GeV. The macroscopic fast neutron removal cross-sections (ΣR have also been calculated. Appreciable variations were noted for all the interaction parameters by varying the photon energy and the chemical composition of the glass samples. The better shielding properties of borate glass samples containing PbO were found. These results indicated that borate glass samples are a good radiation shielding material.

  2. Structure and lattice dynamics in non-centrosymmetric borates; Struktur und Gitterdynamik in azentrischen Boraten

    Energy Technology Data Exchange (ETDEWEB)

    Stein, W.D.R.

    2007-04-23

    This thesis deals with a study of structural and lattice dynamical properties of some noncentrosymmetric borates with outstanding non-linear optical properties. The focus was on the compound bismuth triborate (BiB{sub 3}O{sub 6}). The structure of the tetraborates MB{sub 4}O{sub 7} (M=Pb,Sr,Ba) was also investigated. The structural investigations in bismuth triborate include powder and single crystal diffraction experiments on X-ray and neutron sources. The crystal structure was under examination in the temperature range from 100 K to room temperature and the lattice constants in the temperature range from 20 K to 800 K. The lattice constants show a nearly linear dependency from temperature. Our observations are in good agreement with investigations of the thermal expansion, which shows a strong anisotropy within the layer-like structure of bismuth triborate. Within the borate layers, along the polar axis a strong positive and in the orthogonal direction a negative thermal expansion is observed. This effect can be explained by a zig-zag effect within the borate layers. The lone electron pair at the bismuth atom is discussed to be possibly the origin of the temperature dependency of the coordination environment of the bismuth atom. The influence of the lone electron pair on the crystal structure is raising by lowering the temperature. At the bismuth atom distinct anharmonic effects are observed, where the maximum points along the direction of the polar axis and therefore along the direction of the lone electron pair. The phonon dispersion of bismuth triborate has been investigated by inelastic neutron scattering. The low symmetry of the crystal structure depicts to be a special challenge. The dispersion was observed along the three reciprocal lattice constants. Along the polar axis the dispersion could be characterized to a maximum energy of 20 THz. The low energy acoustic branch along the polar axis shows a softening at the zone boundary. In the orthogonal

  3. Structural influence of mixed transition metal ions on lithium bismuth borate glasses

    Science.gov (United States)

    Yadav, Arti; Dahiya, Manjeet S.; Hooda, A.; Chand, Prem; Khasa, S.

    2017-08-01

    Lithium bismuth borate glasses containing mixed transition metals having composition 7CoO·23Li2O·20Bi2O3·50B2O3 (CLBB), 7V2O5·23Li2O·20Bi2O3·50B2O3 (VLBB) and x(2CoO·V2O5)·(30 - x)Li2O·20Bi2O3·50B2O3 (x = 0.0 (LBB) and x = 2.0, 5.0, 7.0, 10.0 mol% (CVLBB1-4)) are synthesized via melt quench route. The synthesized compositions are investigated for their physical properties using density (D) and molar volume (Vm), thermal properties by analyzing DSC/TG thermo-graphs, structural properties using IR absorption spectra in the mid-IR range and optical properties using UV-Vis-NIR spectroscopy. The Electron Paramagnetic Resonance (EPR) spectra of vanadyl and cobalt ion have been analyzed to study compositional effects on spin-Hamiltonian parameters. The non linear variations in physical properties depict a strong structural influence of Co/V- oxides on the glassy matrix. The compositional variations in characteristic temperatures (glass transition temperature Tg, glass crystallization temperature Tp and glass melting temperature Tm) reveals that Tg for glass samples CLBB is relatively less than that of pure lithium bismuth borate (LBB) glass sample wherein Tg for sample VLBB is higher than that of LBB. The increase in Tg (as compared with LBB) with an enhanced substitution of mixed transition metal oxides (2CoO·V2O5) shows a progressive structure modification of bismuth borate matrix. These predictions are very well corroborated by corresponding compositional trends of Tp and Tm. FTIR studies reveal that Co2+& VO2+ ions lead to structural rearrangements through the conversion of three-coordinated boron into four coordinated boron and thereby reducing number of non-bridging oxygen atoms. Bismuth is found to exist in [BiO6] octahedral units only, whereas boroxol rings are not present in the glass network. The theoretical values of optical basicity (Λth) and corresponding oxide ion polarizability (αo2-) have also been calculated to investigate oxygen covalency of

  4. Overview of ultraviolet and infrared spectroscopic properties of Yb{sup 3+} doped borate and oxy-borates compounds; De l'ultraviolet a l'infrarouge: caracterisation spectroscopique de materiaux type borate et oxyborate dopes a l'ytterbium trivalent

    Energy Technology Data Exchange (ETDEWEB)

    Sablayrolles, J

    2006-12-15

    The trivalent ytterbium ion can give rise to two emissions with different spectroscopic properties: the first one, with a short lifetime, in the ultraviolet (charge transfer emission) is used in detectors such as scintillators, and the other one, with a long lifetime, in the infrared (4f-4f emission) for laser applications. The strong link between material structure and properties is illustrated through ytterbium luminescence study, in the ultraviolet and infrared, inserted in the borate Li{sub 6}Y(BO{sub 3}){sub 3} and two oxy-borates: LiY{sub 6}O{sub 5}(BO{sub 3}){sub 3} and Y{sub 17,33}B{sub 8}O{sub 38}. For the first time an ytterbium charge transfer emission in oxy-borates has been observed. The calculation of the single configurational coordinate diagram, as well as the thermal quenching, has been conducted under a fundamental approach on the ytterbium - oxygen bond. The study of the ytterbium infrared spectroscopy in these compounds has been realised and an energy level attribution is proposed in the particular case of the borate Li{sub 6}Y(BO{sub 3}){sub 3}: Yb{sup 3+}. An original approach is introduced with the study of the charge transfer states for the three compounds by looking at the infrared emission. The first laser performances in three operating modes (continuous wave, Q-switch and mode locking) of a Li{sub 6}Y(BO{sub 3}){sub 3}: Yb{sup 3+} crystal are reported. (author)

  5. Role of oxygen on the optical properties of borate glass doped with ZnO

    International Nuclear Information System (INIS)

    Abdel-Baki, Manal; El-Diasty, Fouad

    2011-01-01

    Lithium tungsten borate glass (0.56-x)B 2 O 3 -0.4Li 2 O-xZnO-0.04WO 3 (0≤x≤0.1 mol%) is prepared by the melt quenching technique for photonic applications. Small relative values of ZnO are used to improve the glass optical dispersion and to probe as well the role of oxygen electronic polarizability on its optical characteristics. The spectroscopic properties of the glass are determined in a wide spectrum range (200-2500 nm) using a Fresnel-based spectrophotometric technique. Based on the Lorentz-Lorenz theory, as ZnO content increases on the expense of B 2 O 3 the glass molar polarizability increased due to an enhanced unshared oxide ion 2p electron density, which increases ionicity of the chemical bonds of glass. The role of oxide ion polarizability is explained in accordance with advanced measures and theories such as optical basicity, O 1s binding energy, the outer most cation binding energy in Yamashita-Kurosawa's interionic interaction parameter and Sun's average single bond strength. FT-IR measurements confirm an increase in bridging oxygen bonds, as a result of replacement of ZnO by B 2 O 3 , which increase the UV glass transmission window and transmittance. - Graphical abstract: O1s, Yamashita-Kurosawa's parameter and average single bond strength of charge overlapping between electronic shells are used to explain enhanced oxide ion 2p electron density, which increases refractive index of glasses. Highlights: → New borate glass for photonic application is prepared. → The dispersion property of the glass is effectively controlled using small amounts of ZnO. → ZnO is used to probe the glass structure and investigate the role of oxygen on the obtained optical properties of the glasses. → Modern theories are used to explain enhanced unshared oxide ion 2p electron density, which increases ionicity of chemical bonds of the glass.

  6. Theoretical isotopic fractionation between structural boron in carbonates and aqueous boric acid and borate ion

    Science.gov (United States)

    Balan, Etienne; Noireaux, Johanna; Mavromatis, Vasileios; Saldi, Giuseppe D.; Montouillout, Valérie; Blanchard, Marc; Pietrucci, Fabio; Gervais, Christel; Rustad, James R.; Schott, Jacques; Gaillardet, Jérôme

    2018-02-01

    The 11B/10B ratio in calcite and aragonite is an important proxy of oceanic water pH. However, the physico-chemical mechanisms underpinning this approach are still poorly known. In the present study, we theoretically determine the equilibrium isotopic fractionation properties of structural boron species in calcium carbonates, BO33-, BO2(OH)2- and B(OH)4- anions substituted for carbonate groups, as well as those of B(OH)4- and B(OH)3 species in vacuum. Significant variability of equilibrium isotopic fractionation properties is observed among these structural species which is related to their contrasted coordination state, Bsbnd O bond lengths and atomic-scale environment. The isotopic composition of structural boron does not only depend on its coordination number but also on its medium range environment, i.e. farther than its first coordination shell. The isotopic fractionation between aqueous species and their counterparts in vacuum are assessed using previous investigations based on similar quantum-mechanical modeling approaches. At 300 K, the equilibrium isotope composition of structural trigonal species is 7-15‰ lighter than that of aqueous boric acid molecules, whereas substituted tetrahedral borate ions are heavier than their aqueous counterparts by 10-13‰. Although significant uncertainties are known to affect the theoretical prediction of fractionation factors between solids and solutions, the usually assumed lack of isotopic fractionation during borate incorporation in carbonates is challenged by these theoretical results. The present theoretical equilibrium fractionation factors between structural boron and aqueous species differ from those inferred from experiments which may indicate that isotopic equilibrium, unlike chemical equilibrium, was not reached in most experiments. Further research into the isotopic fractionation processes at the interface between calcium carbonates and aqueous solution as well as long duration experiments aimed at

  7. The ameliorative effect of grape seed extract(GSE) on sodium borate-inducing kidney injury of male albino rats

    International Nuclear Information System (INIS)

    Ayad, S.K.Y.

    2013-01-01

    Borax (sod-borate) is a toxic compound that is implicated daily to environmental pollutant, so occupational exposure leading to adverse effects on functions of some organs causing their damage as nephrotoxicity, neurotoxicity, hepatotoxicity and testicular atrophy . In particularly, kidney is the most organ that is affected by borax exposure due to continuous exposure with slow rate of excretion leading to accumulation in the renal tissue. Supplementation with high potent antioxidant grape seed extract may alleviate the worse damage effects induced in the kidney as a result of continual exposure of borax in our daily life. The current study aimed to evaluate the ameliorative effect of grape seed extract on renal injury of male albino rats intoxicated with sod-borate. Twenty eight male albino rats were classified to 4 groups(GI and II and III and IV).GI served as a control, group GII was a group intoxicated with sod-borate for 45 days, where as rats in GIII supplemented with GSE beside sod-borate for 45 days , GIV was a group supplemented with GSE only. Serum and kidney samples were collected for biochemical, histopathological and DNA examinations. Significant elevation in the levels of blood urea and creatinine in GII were observed when compared to control group(GI). Significant decline were prominent in biochemical kidney functions when intoxicated group supplemented with GSE(GIII) , where as non significant changes were observed between control group and group supplemented with GSE only (GIV). Significant increase in both cytokines TNF-α and IL-6 was observed in group intoxicated with sod-borate(GII) when compared to control rats(GI). Oral supplementation with high potent antioxidant GSE (GIII) caused alleviation in the kidney injury leading to the reduction of both pro-inflammatory mediator cytokines TNF-α and IL-6. DNA% fragment migration showed that worse significant migration of DNA fragements were observed in toxicated group(GII) followed by increase in

  8. Moessbauer effect study of oxidation and coordination states of iron in some sodium borate glasse:;

    International Nuclear Information System (INIS)

    Eissa, N.A.; Sanad, A.M.; Youssef, S.M.; El-Henawii, S.A.; Gomaa, S.Sh.; Mostafa, A.G.

    1980-01-01

    A structural study of some sodium borate glasses containing iron was carried out applying ME spectroscopy. Both oxidation and coordination states of iron were investigated under the effect of gradual replacing of sodium carbonate by sodium nitrate in the glass batches. The glasses were melted in porcelain crucibles using an electrically heated furnace at 1000+-10 deg C, then were quenched on a steel plate at room temperature (R.T.). The ME source was 20 mCi radioactive Co-57 in chromium. The obtained ME spectra indicated that at lower sodium nitrate content both Fe 2+ and Fe 3+ are present in these glasses. At moderate concentrations some Fe 3+ ions were separated in a crystalline phase and the rest of the iron ions appeared as ferric ions in glassy state. At high sodium nitrate content only Fe 3+ ions in glassy state were detected. The values of the ME parameters for all iron ions indicated that all of them are in the octahedral coordination state. The density measurements confirm the separation of a crystalline phase at moderate sodium nitrate content. (author)

  9. Microstructure characteristics of high borated stainless steel fabricated by hot-pressing sintering

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Xuan; Wang, Mingjia, E-mail: mingjiawangysu@126.com; Zhao, Hongchang

    2016-04-25

    The present study investigated the microstructure of powder metallurgy (P/M) high borated stainless steel through hot-pressing sintering in a temperature range of 1000–1150 °C within 30 min under 30 MPa. Microstructure and phase examinations were carried out by applying scanning electron microscope, electron backscatter diffraction and X-ray diffraction analysis. The results of as-atomized powders demonstrated that many powders kept egg-type structure with an austenite outer layer and the eutectic borides were much finer than those in traditional cast products. Microstructure studies revealed that borides suffered Ostwald ripening and were significantly influenced by the sintering temperature. Orientation maps indicated that the inter-particle contact areas consisted of equiaxed grains and the regions consisting of large elongated grains partly inherited the microstructure characteristics of as-atomized powder particles. Furthermore, the mechanisms governing the morphological changes in microstructure were discussed. - Highlights: • Near-complete densification could be obtained through hot-pressing sintering. • There was no phase transformation and present phases were M{sub 2}B and austenite. • Borides suffered Ostwald ripening and were significantly influenced by temperature. • Inter-particle contact areas consisted of equiaxed grains for recrystallization. • Deformation-free zones exhibited elongated grains for dendritic arms coarsening.

  10. A model for the stabilization of atomic hydrogen centers in borate glasses

    International Nuclear Information System (INIS)

    Pontuschka, W.M.; Isotani, S.; Furtado, W.W.; Piccini, A.; Rabbani, S.R.

    1989-04-01

    A model describing the trapping site of the interstitial atomic hydrogen (H sup(0) sub(i) in borate glasses x-irradiated at 77 K is proposed. The hydrogen atom is stabilized at the centers of oxygen polygons belonging to B-O ring structures in the glass network by van der Waals forces. The previously reported H sup(0) sub(i) isothermal decay experimental data are discussed in the light of this microscopic model. A coupled differential equation system describing the possible reactions was numerically solved by means of Runge-Kutta's method. The parameter best fit was found by trial and error. The untrapping parameter provided an activation energy of 0.7 x 10 sup(-19) J, in good agreement with the calculated results for dispersion interactions between the stabilized atomic hydrogen and the neighbouring oxygen atoms at the vertices of hexagonal and heptagonal structures. The retrapping and recombination parameters were found to be correlated to (T sup1/2) - T sup(1/2) sub(0)) where t sub(0)=179 K is a cutoff temperature for the kinetics process. (author)

  11. Isotope effect in glass-transition temperature and ionic conductivity of lithium-borate glasses

    International Nuclear Information System (INIS)

    Nagasaki, Takanori; Morishima, Ryuta; Matsui, Tsuneo

    2002-01-01

    The glass-transition temperature and the electrical conductivity of lithium borate (0.33Li 2 O-0.67B 2 O 3 ) glasses with various isotopic compositions were determined by differential thermal analysis and by impedance spectroscopy, respectively. The obtained glass-transition temperature as well as the vibrational frequency of B-O network structure was independent of lithium isotopic composition. This result indicates that lithium ions, which exist as network modifier, only weakly interact with B-O network structure. In addition, the glass-transition temperature increased with 10 B content although the reason has not been understood. The electrical conductivity, on the other hand, increased with 6 Li content. The ratio of the conductivity of 6 Li glass to that of 7 Li glass was found to be 2, being larger than the value (7/6) 1/2 calculated with the simple classical diffusion theory. This strong mass dependence could be explained by the dynamic structure model, which assumes local structural relaxation even far below the glass-transition temperature. Besides, the conductivity appeared to increase with the glass-transition temperature. Possible correlations between the glass-transition temperature and the electrical conductivity were discussed. (author)

  12. Dosimetric and kinetic parameters of lithium cadmium borate glasses doped with rare earth ions

    Directory of Open Access Journals (Sweden)

    J. Anjaiah

    2014-10-01

    Full Text Available Thermoluminescence (TL characteristics of X-ray irradiated pure and doped with four different rare earth ions (viz., Pr3+, Nd3+, Sm3+ and Eu3+ Li2O–Cdo–B2O3 glasses have been studied in the temperature range 303–573 K; the pure glass has exhibited single TL peak at 466 K. When this glass is doped with different rare earth ions no additional peaks are observed but the glow peak temperature of the existing glow peak shifted gradually towards higher temperatures with gain in intensity of TL light output. The area under the glow curve is found to be maximum for Eu3+ doped glasses. The trap depth parameters associated with the observed TL peaks have been evaluated using Chen's formulae. The possible use of these glasses in radiation dosimetry has been described. The result clearly showed that europium doped cadmium borate glass has a potential to be considered as the thermoluminescence dosimeter.

  13. Enhanced osteointegration of poly(methylmethacrylate) bone cements by incorporating strontium-containing borate bioactive glass.

    Science.gov (United States)

    Cui, Xu; Huang, Chengcheng; Zhang, Meng; Ruan, Changshun; Peng, Songlin; Li, Li; Liu, Wenlong; Wang, Ting; Li, Bing; Huang, Wenhai; Rahaman, Mohamed N; Lu, William W; Pan, Haobo

    2017-06-01

    Although poly(methylmethacrylate) (PMMA) cements are widely used in orthopaedics, they have numerous drawbacks. This study aimed to improve their bioactivity and osseointegration by incorporating strontium-containing borate bioactive glass (SrBG) as the reinforcement phase and bioactive filler of PMMA cement. The prepared SrBG/PMMA composite cements showed significantly decreased polymerization temperature when compared with PMMA and retained properties of appropriate setting time and high mechanical strength. The bioactivity of SrBG/PMMA composite cements was confirmed in vitro , evidenced by ion release (Ca, P, B and Sr) from SrBG particles. The cellular responses of MC3T3-E1 cells in vitro demonstrated that SrBG incorporation could promote adhesion, migration, proliferation and collagen secretion of cells. Furthermore, our in vivo investigation revealed that SrBG/PMMA composite cements presented better osseointegration than PMMA bone cement. SrBG in the composite cement could stimulate new-bone formation around the interface between the composite cement and host bone at eight and 12 weeks post-implantation, whereas PMMA bone cement only stimulated development of an intervening connective tissue layer. Consequently, the SrBG/PMMA composite cement may be a better alternative to PMMA cement in clinical applications and has promising orthopaedic applications by minimal invasive surgery. © 2017 The Author(s).

  14. Physical and spectroscopic studies on manganese ions in lead halo borate glasses

    Science.gov (United States)

    Sekhar, K. Chandra; Hameed, Abdul; Ramadevudu, G.; Chary, M. Narasimha; Shareefuddin, Md.

    2017-06-01

    Lead halo borate glass systems containing manganese ions have been investigated to study the role of halide ions on the physical, optical and EPR studies. The amorphous phase of the prepared glass samples xPbX2-(30 - x)PbO-69.5B2O3-0.5MnO2 with X = F, Cl and Br and 5 ≤ x ≤ 25 mol% was confirmed from their X-ray diffraction spectra. Ionic radii of the halides played an important role in the physical properties. From the optical absorption spectra, optical band gap and Urbach energy values were evaluated. The EPR spectra have shown a six-line hyperfine (HF) structure centered at g ≈ 2.0 and attributed to Mn2+ centers in octahedral symmetry. The other signals at g ≈ 3.3 and 4.3 were attributed to the rhombic surroundings of Mn2+ ions. The negative shift in g-value revealed highly ionic environment around the Mn2+ ion in the glass hosts. The HF splitting constant (A), number of spins (N) and susceptibility (χ) values of the prepared glasses were also reported.

  15. Effects of copper on the preparation and characterization of Na-Ca-P borate glasses.

    Science.gov (United States)

    Shailajha, S; Geetha, K; Vasantharani, P; Sheik Abdul Kadhar, S P

    2015-03-05

    Glasses in the system Na2O-CaO-B2O3-P2O5: CuO have been prepared by melt quenching at 1200°C and rapidly cooling at room temperature. The structural, optical and thermal properties have been investigated using X-ray diffraction (XRD), ultraviolet-visible (UV-VIS) spectroscopy, thermogravimetric-differential thermal analysis (TG-DTA), Fourier transform infrared (FTIR) spectroscopy, high resolution scanning electron microscopy (HRSEM) with energy dispersive X-ray (EDX) spectroscopy and high resolution transmission electron microscope (HRTEM) with energy dispersive X-ray (EDAX). The amorphous and crystalline nature of these samples was verified by XRD. Glass transition, crystallization and thermal stability were determined by TG-DTA investigations. Direct optical energy band gaps before and after doping with different percents of copper oxide were evaluated from 4.81eV to 2.99eV indicated the role of copper in the glassy matrix by UV spectra. FTIR spectrum reveals characteristic absorption bands due to various groups of triangular and tetrahedral borate network. Due to the amorphous nature, the particles like agglomerates on the glass surface were investigated by the HRSEM analysis. The crystalline nature of the samples in XRD is confirmed by SAED pattern using HRTEM. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Ho3+-doped strontium-aluminium-bismuth-borate glasses for green light emission.

    Science.gov (United States)

    Rajesh, D; Dhamodhara Naidu, M; Ratnakaram, Y C; Balakrishna, A

    2014-11-01

    Strontium-aluminium-bismuth-borate glasses (SAlBiB) doped with different concentrations of Ho(3+) were prepared using conventional melt quenching technique and their structural and optical properties investigated. X-ray diffraction and scanning electron microscopy analysis were used to study the structural properties. Optical properties were studied by measuring the optical absorption and visible luminescence spectra. The Judd-Ofelt (J-O) theory was applied to evaluate J-O intensity parameters, Ω(λ) (λ = 2, 4 and 6). Using J-O intensity parameters, radiative properties such as spontaneous transition probabilities (A(R)), branching ratios (β(R)) and radiative lifetimes (τ(R)) were determined. From the emission spectra, a strong green emission nearly at 549 nm corresponding to the transition, (5)S2 ((5)F4)→(5)I(8) was observed. Emission peak positions (λ(P)), effective bandwidths (Δλ(eff)) and stimulated emission cross-sections (σ(p)) were calculated for the observed emission transitions, (5)F3 →(5)I(8), (5)S2((5)F4)→(5)I(8) and (5)F5 →(5)I(8) of Ho(3+) in all the glass matrices. Chromaticity color coordinates were calculated using the emission spectra. The experimental results suggest that SAlBiB glass matrix with 1.5 mol% of Ho(3+) has better emission properties. Copyright © 2014 John Wiley & Sons, Ltd.

  17. Thermoluminescence properties of lithium magnesium borate glasses system doped with dysprosium oxide.

    Science.gov (United States)

    Mhareb, M H A; Hashim, S; Ghoshal, S K; Alajerami, Y S M; Saleh, M A; Razak, N A B; Azizan, S A B

    2015-12-01

    We report the impact of dysprosium (Dy(3+)) dopant and magnesium oxide (MgO) modifier on the thermoluminescent properties of lithium borate (LB) glass via two procedures. The thermoluminescence (TL) glow curves reveal a single prominent peak at 190 °C for 0.5 mol% of Dy(3+). An increase in MgO contents by 10 mol% enhances the TL intensity by a factor of 1.5 times without causing any shift in the maximum temperature. This enhancement is attributed to the occurrence of extra electron traps created via magnesium and the energy transfer to trivalent Dy(3+) ions. Good linearity in the range of 0.01-4 Gy with a linear correlation coefficient of 0.998, fading as low as 21% over a period of 3 months, excellent reproducibility without oven annealing and tissue equivalent effective atomic numbers ~8.71 are achieved. The trap parameters, including geometric factor (μg), activation energy (E) and frequency factor (s) associated with LMB:Dy are also determined. These favorable TL characteristics of prepared glasses may contribute towards the development of Li2O-MgO-B2O3 radiation dosimeters. Copyright © 2015 John Wiley & Sons, Ltd.

  18. Optical studies of Sm³⁺ ions doped zinc alumino bismuth borate glasses.

    Science.gov (United States)

    Swapna, K; Mahamuda, Sk; Srinivasa Rao, A; Shakya, S; Sasikala, T; Haranath, D; Vijaya Prakash, G

    2014-05-05

    Zinc Alumino Bismuth Borate (ZnAlBiB) glasses doped with different concentrations of samarium (Sm(3+)) ions were prepared by using melt quenching technique and characterized for their lasing potentialities in visible region by using the techniques such as optical absorption, emission and emission decay measurements. Radiative properties for various fluorescent levels of Sm(3+) ions were estimated from absorption spectral information using Judd-Ofelt (JO) analysis. The emission spectra and con-focal photoluminescence images obtained by 410 nm laser excitation demonstrates very distinct and intense orange-red emission for all the doped glasses. The suitable concentration of Sm(3+) ions in these glasses to act as an efficient lasing material has been discussed by measuring the emission cross-section and branching ratios for the emission transitions. The quantum efficiencies were also been estimated from emission decay measurements recorded for the (4)G5/2 level of Sm(3+) ions. From the measured emission cross-sections, branching ratios, strong photoluminescence features and CIE chromaticity coordinates, it was found that 1 mol% of Sm(3+) ions doped ZnAlBiB glasses are most suitable for the development of visible orange-red lasers. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. The impact of gallium content on degradation, bioactivity, and antibacterial potency of zinc borate bioactive glass.

    Science.gov (United States)

    Rahimnejad Yazdi, Alireza; Torkan, Lawrence; Stone, Wendy; Towler, Mark R

    2018-01-01

    Zinc borate glasses with increasing gallium content (0, 2.5, 5, 10, and 15 Wt % Ga) were synthesized and their degradation, bioactivity in simulated body fluid (SBF), and antibacterial properties were investigated. ICP measurements showed that increased gallium content in the glass resulted in increased gallium ion release and decreased release of other ions. Degradability declined with the addition of gallium, indicating the formation of more symmetric BO 3 units with three bridging oxygens and asymmetric BO 3 units with two bridging oxygens in the glass network as the gallium content in the series increased. The formation of amorphous CaP on the glass surface after 24 h of incubation in SBF was confirmed by SEM, XRD, and FTIR analyses. Finally, antibacterial evaluation of the glasses using the agar disc-diffusion method demonstrated that the addition of gallium increased the antibacterial potency of the glasses against P. aeruginosa (Gram-negative) while decreasing it against S. epidermidis (Gram-positive); considering the ion release trends, this indicates that the gallium ion is responsible for the glasses' antibacterial behavior against P. aeruginosa while the zinc ion controls the antibacterial activity against S. epidermidis. The statistical significance of the observed trends in the measurements were confirmed by applying the Kruskal-Wallis H Test. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 367-376, 2018. © 2017 Wiley Periodicals, Inc.

  20. Effect of La2O3 on the structure and the properties of strontium borate glasses

    Directory of Open Access Journals (Sweden)

    Smiljanić Sonja V.

    2016-01-01

    Full Text Available The selected lanthanum-strontium-borate glasses were prepared by a conventional melt-quenching technique. The compositions of the investigated glasses were chosen to be: 5.7, 9.5, 14.3, 19.1 mol % for La2O3, 22.9, 19.1, 14.3, 9.5 for mol % SrO and 71.4 mol % for B2O3. The density, molar volume, oxygen molar volume, oxygen packing density, oxygen/boron ratios and structural transformations in the glass network were investigated according to the substitution of SrO by La2O3. The density and the molar volume increased in parallel with La2O3 content increase. Simultaneously, oxygen molar volume values increased while the oxygen packing density values decreased. A hot stage microscope (HSM and a differential thermal analysis (DTA were used to determine the characteristic temperatures. By increasing the content of lanthanum, the glass transition temperatures, changed with the same trend as the molar volume. Glass stability parameters were calculated from the temperatures obtained by DTA and HSM. The HSM results were used to obtain the viscosity curves by applying Vogel-Fulcher-Tamman (VFT equation. [Projekat Ministarstva nauke Republike Srbije, br. 172004 i br. 34001

  1. Luminescence features of dysprosium and phosphorus oxide co-doped lithium magnesium borate glass

    Science.gov (United States)

    Hashim, S.; Mhareb, M. H. A.; Ghoshal, S. K.; Alajerami, Y. S. M.; Saripan, M. I.; Bradley, D. A.

    2017-08-01

    Lithium magnesium borate (LMB) glass system co-doped with the oxides of dysprosium (Dy2O3) and phosphorus (P2O5) were synthesized using melt-quenching method. Prepared samples were characterized using various techniques to determine the effects of co-dopants concentration variation on their thermoluminescence (TL) and photoluminescence (PL) properties. TL glow curves of LMB:0.5Dy sample revealed a single prominent peak at Tm=190 °C, where TL intensity was enhanced by a factor of 2.5 with the increase of P2O5 concentration up to 1 mol%. This enhancement was accompanied by a shift in Tm towards higher temperature. Good linearity in the range of 1-100 Gy with linear correlation coefficient of 0.998 was achieved. PL spectra displayed two significant peaks centred at 481 nm and 573 nm. These attractive luminescence features of the proposed glass system may be useful for the development of radiation dosimetry.

  2. Spectroscopic investigations of Nd3+ doped flouro- and chloro-borate glasses.

    Science.gov (United States)

    Mohan, Shaweta; Thind, Kulwant Singh; Sharma, Gopi; Gerward, Leif

    2008-10-01

    Spectroscopic and physical properties of Nd3+ doped sodium lead flouro- and chloro-borate glasses of the type 20NaX-30PbO-49.5B2O3-0.5Nd2O3 (X=F and Cl) have been investigated. Optical absorption spectra have been used to determine the Slater Condon (F2, F4, and F6), spin orbit xi4f and Racah parameters (E1, E2, and E3). The oscillator strengths and the intensity parameters Omega2, Omega4 and Omega6 have been determined by the Judd-Ofelt theory, which in turn provide the radiative transition probability (A), total transition probability (A(T)), radiative lifetime (tauR) and branching ratio (beta) for the fluorescent level 4F3/2. The lasing efficiency of the prepared glasses has been characterized by the spectroscopic quality factor (Omega4/Omega6), the value of which is in the range of 0.2-1.5, typical for Nd3+ in different laser hosts. Nephelauxetic effect results in a red shift in the energy levels of Nd3+ for chloroborate glass. The radiative transition probability of the potential lasing transition 4F3/2-->4I11/2 of Nd3+ ions is found to be higher for flouroborate as compared to chloroborate glass.

  3. Ethylene glycol assisted low-temperature synthesis of boron carbide powder from borate citrate precursors

    Directory of Open Access Journals (Sweden)

    Rafi-ud-din

    2014-09-01

    Full Text Available B4C powders were synthesized by carbothermal reduction of ethylene glycol (EG added borate citrate precursors, and effects of EG additions (0–50 mol% based on citric acid on the morphologies and yields of synthesized B4C powders were investigated. The conditions most suitable for the preparation of precursor were optimized and optimum temperature for precursor formation was 650 °C. EG additions facilitated low-temperature synthesis of B4C at 1350 °C, which was around 100–300 °C lower temperature compared to that without EG additions. The lowering of synthesis temperature was ascribed to the enlargement of interfacial area caused by superior homogeneity and dispersibility of precursors enabling the diffusion of reacting species facile. The 20% EG addition was optimal with free residual carbon lowered to 4%. For smaller EG additions, the polyhedral and rod-like particles of synthesized product co-existed. With higher EG additions, the morphology of synthesized product was transformed into needle and blade-like structure.

  4. Infrared luminescence and thermoluminescence of lithium borate glasses doped with Sm3+ ions

    Directory of Open Access Journals (Sweden)

    Anjaiah J.

    2015-03-01

    Full Text Available Thermoluminescence (TL characteristics of X-ray irradiated pure and doped with Sm3+ ions Li2O-MO-B2O3 (where MO=ZnO, CaO, CdO glasses have been studied in the temperature range of 303 to 573 K. All the pure glasses exhibited single TL peaks at 382 K, 424 K and 466 K. When these glasses were doped with Sm3+ ions no additional peaks have been observed but the glow peak temperature of the existing glow peak shifted gradually towards higher temperatures with gain in intensity of TL light output. The area under the glow curve was found to be maximum for Sm3+ doped glasses mixed with cadmium oxide as a modifier. The trap depth parameters associated with the observed TL peaks have been evaluated using Chen’s formulae. The possible use of these glasses in radiation dosimetry has been described. The results clearly showed that samarium doped cadmium borate glass has a potential to be considered as a thermoluminescence dosimeter.

  5. Optical characterization of Eu3+ and Tb3+ ions doped zinc lead borate glasses.

    Science.gov (United States)

    Thulasiramudu, A; Buddhudu, S

    2007-02-01

    This paper reports on the spectral analysis of Eu3+ or Tb3+ ions (0.5 mol%) doped heavy metal oxide (HMO) based zinc lead borate glasses from the measurement of their absorption, emission spectra and also different physical properties. From the XRD, DSC profiles, the glass nature and glass thermal properties have been studied. The measured emission spectrum of Eu3+ glass has revealed five transitions (5D0-->7F0, 7F1, 7F2, 7F3 and 7F4) at 578, 591, 613, 654 and 702 nm, respectively, with lambdaexci=392 nm (7F0-->5L6). In the case of Tb3+:ZLB glass, four emission transitions such as (5D4-->7F6, 7F5, 7F4 and 7F3) that are located at 489, 542, 585 and 622 nm, respectively, have been measured with lambdaexci=374 nm. For all these emission bands decay curves have been plotted to evaluate their lifetimes and the emission processes that arise in the glasses have been explained in terms of energy level schemes.

  6. Effects of Chemically Doped Bioactive Borate Glass on Neuron Regrowth and Regeneration.

    Science.gov (United States)

    Gupta, Brinda; Papke, Jason B; Mohammadkhah, Ali; Day, Delbert E; Harkins, Amy B

    2016-12-01

    Peripheral nerve injuries present challenges to regeneration. Currently, the gold standard for nerve repair is an autograft that results in another region of the body suffering nerve damage. Previously, bioactive borate glass (BBG) has been studied in clinical trials to treat patients with non-healing wounds, and we have reported that BBG is conducive for soft tissue repair. BBG provides structural support, degrades in a non-cytotoxic manner, and can be chemically doped. Here, we tested a wide range of chemical compounds that are reported to have neuroprotective characteristics to promote regeneration of peripheral neurons after traumatic injury. We hypothesized that chemical dopants added in trace amounts to BBG would improve neuronal survival and neurite outgrowth from dorsal root ganglion (DRG) explants. We measured neurite outgrowth from whole DRG explants, and survival rates of dissociated neurons and support cells that comprise the DRG. Results show that chemically doped BBGs have differentially variable effects on neuronal survival and outgrowth, with iron, gallium, and zinc improving outgrowth of neurons, and iodine causing the most detriment to neurons. Because chemically doped BBGs support increased nerve regrowth and survival, they show promise for use in peripheral nerve regeneration.

  7. Low loss photonic components in high index bismuth borate glass by femtosecond laser direct writing.

    Science.gov (United States)

    Yang, Weijia; Corbari, Costantino; Kazansky, Peter G; Sakaguchi, Koichi; Carvalho, Isabel C S

    2008-09-29

    Single mode, low loss waveguides were fabricated in high index bismuth borate glass by femtosecond laser direct writing. A specific set of writing parameters leading to waveguides perfectly mode matched to standard single-mode fibers at 1.55 microm with an overall insertion loss of approximately 1 dB and with propagation loss below 0.2 dB/cm was identified. Photonic components such as Y-splitters and directional couplers were also demonstrated. A close agreement between their performances and theoretical predictions based upon the characterization of the waveguide properties is shown. Finally, the nonlinear refractive index of the waveguides has been measured to be 6.6 x 10(-15) cm(2)/W by analyzing self-phase modulation of the propagating femtosecond laser pulse at the wavelength of 1.46 microm. Broadening of the transmitted light source as large as 500 nm was demonstrated through a waveguide with the length of 1.8 cm.

  8. In situ hydroxyapatite nanofiber growth on calcium borate silicate ceramics in SBF and its structural characteristics.

    Science.gov (United States)

    Pu, Yinfu; Huang, Yanlin; Qi, Shuyun; Chen, Cuili; Seo, Hyo Jin

    2015-10-01

    A novel calcium silicate borate Ca11Si4B2O22 ceramic was firstly prepared by the conventional solid-state reaction. In vitro hydroxyapatite mineralization was investigated by soaking the ceramics in simulated body fluid (SBF) solutions at body temperature (37 °C) for various time periods. Scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD) measurements were applied to investigate the samples before and after the immersion of ceramics in SBF solution. The elemental compositions of a hydroxyapatite layer on the ceramics during the mineralization were confirmed by X-ray energy-dispersive spectra (EDS). Meanwhile, the bending strength and elastic modulus of Ca11Si4B2O22 ceramics were also measured, which indicate that the biomaterials based on Ca11Si4B2O22 ceramics possess bioactivity and might be a potential candidate as biomaterials for hard tissue repair. The bioactive mineralization ability was evaluated on the base of its crystal structural characteristics, i.e., silanol (Si-OH) and B-OH groups can be easily induced on the surface of Ca11Si4B2O22 ceramics soaked in SBF solutions. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Solubility of YAG:Nd in borate glass-luminescence and Raman investigation

    Energy Technology Data Exchange (ETDEWEB)

    Ryba-Romanowski, W. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okolna 2, 50-422 Wroclaw (Poland); Solarz, P., E-mail: solarz@int.pan.wroc.pl [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okolna 2, 50-422 Wroclaw (Poland); Kasprowicz, D.; Runka, T. [Faculty of Technical Physics, Poznan University of Technology, Nieszawska 13 A, 60-965 Poznan (Poland); Szysiak, A.; Stepien, R. [Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland)

    2011-05-26

    Highlights: > In the present work we investigate glass-ceramic systems obtained by melting the sintered samples mentioned above. > Intention of the work is to get a more close insight into the nature of luminescent centres in these materials. In the first approach low temperature luminescence spectra recorded upon a bulk excitation, denoted as 'macroscopic' are analysed to assess the effect of the solubility of crystalline phase. > In the second approach denoted as 'microscopic' selected areas of samples were illuminated by an incident light beam with a diameter of about 1 micrometer and resulting Raman scattering spectra and luminescence spectra are compared. - Abstract: YAG:Nd powders obtained by grinding a single crystal and synthesized by modified sol-gel and combustion methods were embedded at the stage of melting in a multicomponent borate glass to obtain luminescent glass-ceramic systems. Room temperature optical absorption spectra, luminescence spectra at room temperature and at 10 K and micro-Raman spectra were recorded to determine the location of Nd{sup 3+} ions in composite materials. It has been concluded that their luminescence characteristics depend critically on the preparation method hence the morphology of precursor crystalline YAG:Nd powders as a consequence of dissimilar solubility of crystallites in a host glass.

  10. Protected (fluoroaryl)borates as effective counteranions for cationic metallocene polymerization catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Jia, L.; Yang, X.; Ishihara, Atsushi; Marks, T.J. [Northwestern Univ., Evanston, IL (United States)

    1995-07-01

    The functionalized (fluoroaryl)borate salts Ph{sub 3}C{sup +}B(C{sub 6}F{sub 4}TBS){sub 4}{sup -} and Ph{sub 3}C{sup +}B(C{sub 6}F{sub 4}TBS){sub 4}{sup -} and (TBS - {sup t}BuMe{sub 2}Si; TIPS = {sup i}Pr{sub 3}Si) are prepared in three steps from 1,4-HC{sub 6}F{sub 4}Br. Reaction with zirconocene dimethyls yields crystalline, thermally stable, soluble L{sub 2}ZrCH{sub 3}{sup +}B(C{sub 6}F{sub 4}SiR{sub 3}){sub 4}{sup -} and L{sub 2}{sup -}ZrH{sup +}(C{sub 6}F{sub 4}SiR{sub 3}){sub 4}{sup -} salts (L = {eta}{sup 5}-C{sub 5}H{sub 5}; {eta}{sup 5}-1,2-Me{sub 2}C{sub 5}H{sub 3}; L{sup +} = {eta}{sup 5}-Me{sub 5}C{sub 5}) which function as highly active ethylene polymerization catalysts. 16 refs., 1 tab.

  11. Use of borated polyethylene to improve low energy response of a prompt gamma based neutron dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Priyada, P.; Ashwini, U.; Sarkar, P.K., E-mail: pradip.sarkar@manipal.edu

    2016-05-21

    The feasibility of using a combined sample of borated polyethylene and normal polyethylene to estimate neutron ambient dose equivalent from measured prompt gamma emissions is investigated theoretically to demonstrate improvements in low energy neutron dose response compared to only polyethylene. Monte Carlo simulations have been carried out using the FLUKA code to calculate the response of boron, hydrogen and carbon prompt gamma emissions to mono energetic neutrons. The weighted least square method is employed to arrive at the best linear combination of these responses that approximates the ICRP fluence to dose conversion coefficients well in the energy range of 10{sup −8} MeV to 14 MeV. The configuration of the combined system is optimized through FLUKA simulations. The proposed method is validated theoretically with five different workplace neutron spectra with satisfactory outcome. - Highlights: • An improved method is proposed for estimating H⁎(10) using prompt gamma emissions. • A combination of BHDPE and HDPE cylinders is used as a sample. • Linear combination of prompt gamma intensities approximates ICRP-DCC closely. • Feasibility of the method was tested theoretically using workplace neutron spectra.

  12. High-temperature borate liquids: physical properties of glass-forming compositions

    Energy Technology Data Exchange (ETDEWEB)

    Riebling, E.F.

    1977-05-06

    Several experimental routes can be used to develop a better understanding of the polymeric constitution (polyanionic and/or polyhedral distribution) of borate, germanate, and silicate glasses. Spectral, chemical, physical-chemical, and mechanical property information can be determined directly for the glass compositions of interest. Generally, only physical-chemical information is readily accessible for the corresponding high temperature liquids. It will be shown that information on each state of matter has its own particular merits. Most of the evidence thus far published suggests an excellent agreement between polyhedral distributions in an oxide glass and its corresponding high temperature liquid state. There is no well known oxide glass forming system for which such a state of affairs does not exist. In spite of this, occasional efforts are put forth which ignore some of what is known for oxide liquids, glasses, and crystals. Such attempts therefore invariably imply, if only indirectly, that significant changes occur in the polyhedral distributions close to the glass transition temperature region. Specific examples to be discussed will include efforts that avoid well known coordination change equilibria such as BO/sub 3/ reversible BO/sub 4/ and GeO/sub 4/ reversible GeO/sub 6/.

  13. Crystal chemistry and temperature behavior of the natural hydrous borate colemanite, a mineral commodity of boron

    Science.gov (United States)

    Lotti, Paolo; Gatta, G. Diego; Demitri, Nicola; Guastella, Giorgio; Rizzato, Silvia; Ortenzi, Marco Aldo; Magrini, Fabrizio; Comboni, Davide; Guastoni, Alessandro; Fernandez-Diaz, Maria Teresa

    2017-11-01

    Colemanite, CaB3O4(OH)3ṡH2O, is the most common hydrous Ca-borate, as well as a major mineral commodity of boron. In this study, we report a thorough chemical analysis and the low-temperature behavior of a natural sample of colemanite by means of a multi-methodological approach. From the chemical point of view, the investigated sample resulted to be relatively pure, its composition being very close to the ideal one, with only a minor substitution of Sr2+ for Ca2+. At about 270.5 K, a displacive phase transition from the centrosymmetric P21/a to the acentric P21 space group occurs. On the basis of in situ single-crystal synchrotron X-ray (down to 104 K) and neutron diffraction (at 20 K) data, the hydrogen-bonding configuration of both the polymorphs and the structural modifications at the atomic scale at varying temperatures are described. The asymmetric distribution of ionic charges along the [010] axis, allowed by the loss of the inversion center, is likely responsible for the reported ferroelectric behavior of colemanite below the phase transition temperature.

  14. Appearance of small polaron hopping conduction in iron modified cobalt lithium bismuth borate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Dahiya, M. S.; Khasa, S., E-mail: skhasa@yahoo.com; Yadav, Arti [Physics Department, Deenbandhu Chhotu Ram University of Science and Technology, Murthal, India-131039 (India); Agarwal, A. [Applied Physics Department, Guru Jambheshwara University of Science and Technology, Hisar, India-125001 (India)

    2016-05-23

    Lithium bismuth borate glasses containing different amounts of cobalt and iron oxides having chemical composition xFe{sub 2}O{sub 3}•(20-x)CoO•30Li{sub 2}O•10Bi{sub 2}O{sub 3}•40B{sub 2}O{sub 3} (x = 0, 5, 10, 15 and 20 mol% abbreviated as CFLBB1-5 respectively) prepared via melt quench technique have been investigated for their dc electrical conductivity. The amorphous nature of prepared glasses has been confirmed through X-ray diffraction measurements. The dc electrical conductivity has been analyzed by applying Mott’s small polaron hopping model. Activation energies corresponding to lower and higher temperature region have been evaluated. The iron ion concentration (N), mean spacing between iron ions (R) and polaron radius (R{sub p}) has been evaluated using the values of phonon radius (R{sub ph}) and Debye temperature (θ{sub D}). The glass sample without iron (CFLBB1) shows ionic conductivity but the incorporation of iron in the glass matrix results in the appearance of electronic conductivity.

  15. Effect of SiO2 addition and gamma irradiation on the lithium borate glasses

    Science.gov (United States)

    Raut, A. P.; Deshpande, V. K.

    2018-01-01

    The physical properties like density, glass transition temperature (Tg), and ionic conductivity of lithium borate (LB) glasses with SiO2 addition were measured before and after gamma irradiation. Remarkable changes in properties have been obtained in the physical properties of LB glasses with SiO2 addition and after gamma irradiation. The increase in density and glass transition temperature of LB glasses with SiO2 addition has been explained with the help of increase in density of cross linking due to SiO4 tetrahedra formation. The increase in ionic conductivity with SiO2 addition was explained with the help of ‘mixed glass former effect’. The increase in density and Tg of LB glasses with SiO2 addition after gamma irradiation has been attributed to fragmentation of bigger ring structure into smaller rings, which increases the density of cross linking and hence compaction. The exposure of gamma irradiation has lead to decrease in ionic conductivity of LB glasses with SiO2 addition. The atomic displacement caused by gamma irradiation resulted in filling of interstices and decrease in trapping sites. This explains the obtained decrease in ionic conductivity after gamma irradiation of glasses. The obtained results of effect of SiO2 addition and gamma irradiation on the density, Tg and ionic conductivity has been supported by FTIR results.

  16. Glass laser discs with annular alkali lead borate coatings and use thereof

    International Nuclear Information System (INIS)

    Cooley, R.F.

    1975-01-01

    A laser assembly that includes a novel glass laser disc having an annular alkali lead borate glass coating for use in the assembly is disclosed. The annular coating has an index of refraction that is about 3 to 12 percent greater than the index of refraction of the laser disc, the thermal properties also being sufficiently matched with the glass laser disc so as to prevent the development of undesirable strains therein, the glass coating comprising a mixture of alkali metal oxides in which at least two different alkali metal oxides are present, and any K 2 O that is present is limited to an amount of not substantially more than about 1 percent by weight and an effective energy absorbing amount of heavy metal oxide that absorbs energy at a wavelength of about 1.06 microns to prevent parasitic oscillations. The heavy metal oxides include oxides of transition metals of the 3d, 4d, 4f, 5d and 5f orbital series. (auth)

  17. Effect of 2-aminoethoxydiphenyl borate on ischemia-reperfusion injury in a rat ovary model.

    Science.gov (United States)

    Taskin, Mine Islimye; Hismiogullari, Adnan Adil; Yay, Arzu; Adali, Ertan; Gungor, Aysenur Cakir; Korkmaz, Gozde Ozge; Inceboz, Umit

    2014-07-01

    The aim of this study is to evaluate the effects of 2-aminoethoxydiphenyl borate (2-APB) as an antioxidant and analyze biochemical and histopathologic changes in experimental ischemia-reperfusion (I/R) injury in rat ovaries. Thirty female rats were utilized to create four groups. Group 1: I/R and 2-APB (2mg/kg); Group 2: I/R and 2-APB (4mg/kg); Group 3: I/R; Group 4: sham operation. Ovarian tissue and serum malondialdehyde, nitric oxide (NO) levels; ovarian tissue and serum total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI) were determined. In ovarian tissue samples histopathologic examination, immunoflourescence staining by TUNEL method was studied. Tissue TOS, serum TOS, and OSI levels were elevated in I/R group. After treatment with 2-APB, tissue and serum TOS levels and OSI levels were markedly decreased. There was a significant difference in terms of tissue and serum NO levels between the sham group and I/R group. Elevation in tissue NO and serum NO levels were decreased after treatment with 2-APB. TUNEL-positive cell number gradually decreased with dose of 2-APB in groups 1 and 2. Conservative treatment with 2-APB is beneficial for mitigation of I/R injury, and the ovarian protective effect of 2-APB appears to be mediated through its antiapopitotic and antioxidative effects. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  18. [Vancomycin-loaded bioactive borate glass for treatment of chronic osteomyelitis in rabbits].

    Science.gov (United States)

    Xie, Zongping; Liu, Xin; Jia, Weitao; Zhang, Changqing; Huang, Wenhai

    2011-07-01

    Bioactive borate glass (BG) has good biocompatibility and biodegradation. To investigate the feasibility of bioactive borate glass as a carrier of the antibiotic controlled-releasing by implanting vancomycin-loaded BG (VBG) into the focus of tibia chronic osteomyelitis after debridement. VBG and vancomycin-loaded calcium sulfate (VCS) were prepared with a vancomycin content of 80 mg/g. Sixty-five New Zealand white rabbits, weighing 2.12-3.91 kg (mean, 2.65 kg), were used. The tibia chronic osteomyelitis rabbit models were established by injecting methicillin-resistant Staphylococcus aureus (MRSA, 0.1 mL, 1 x 10(9) cfu/mL) into the right tibia of 65 rabbits. After 3 weeks of injection, 54 rabbits of successful models were randomly divided into groups A (n=11), B (n=11), C (n=16), and D (n=16). Simple debridement was performed in group A; BG, VCS, and VBG were implanted into the infection sites of groups B, C, and D respectively after thorough debridement. A sample of the debrided tissues was harvested for bacterial examination. The vancomycin serum levels were determined in groups C and D at 1, 2, 4, 10, 24, and 48 hours after operation. The boron serum levels were determined in groups B and D at 10, 24, 48, 72, and 120 hours after operation. After 8 weeks, the effectiveness was assessed radiographically, bacteriologically, and histopathologically. Ten rabbits died after operation. No vancomycin was detected in group C; the vancomycin level increased gradually, reached the highest level at 4 hours after operation, and then decreased rapidly in group D. No boron was detected in group B; the boron reached the highest serum level at 10 hours after operation, and then decreased gradually in group D. At 8 weeks, calcium sulfate degraded in group C; BG degraded partially in group D; and no obvious degradation was observed in group B. The repair effect was better in group D than in group C. There was no significant difference in radiograph scoring between groups A, B, C

  19. Kombinasi Boraks dan Asam Borat sebagai Bahan Penghambat Api dan Antirayap Pada Kayu Meranti Merah

    Directory of Open Access Journals (Sweden)

    Mahdi Santoso

    2015-01-01

    Full Text Available Kayu mempunyai sifat yang mudah terbakar dan sebagian besar mempunyai keawetan alami yang rendah. Perbaikan kualitas kayu dilakukan untuk mengatasi kelemahan tersebut, salah satunya dengan mengimpregnasikan bahan kimia yang bersifat menghambat api dan beracun terhadap organisme perusak kayu. Tujuan penelitian ini adalah melihat kemampuan boraks:asam borat (1:1 untuk meningkatkan ketahanan kayu meranti merah terhadap api dan rayap kayu kering dan mengetahui proses pengawetan yang efektif. Penelitian ini menggunakan kayu meranti merah (Shorea spp berukuran 6 x 15 x 500 cm. Waktu pengawetan adalah 1, 2, dan 3 jam serta konsentrasi bahan pengawet 7% dalam 5 ulangan. Metode pengawetan menggunakan metode sel kosong dengan tekanan 12 kg/cm2 . Pengujian ketahanan terhadap api mengacu pada ASTM E 69-02 prosedur B, pengujian ketahanan terhadap rayap kayu kering mengacu pada metode rayap makan tanpa pilihan. Parameter yang diamati ialah absorpsi, retensi aktual, intensitas bakar, suhu pembakaran maksimal, lama pembaraan, mortalitas rayap kayu kering, pengurangan berat contoh uji, derajat kerusakan dan kondisi fisik sampel setelah uji bakar. Hasil penelitian menunjukkan bahwa kombinasi boraks:asam borat (1:1 memiliki efektivitas yang tinggi untuk meningkatkan ketahanan kayu meranti merah terhadap api dan rayap kayu kering. Proses pengawetan yang paling efektif adalah lama penekanan 2 jam dengan absorpsi 331 kg/m3 ; retensi aktual 28,8 kg/m3 ; intensitas bakar 10,9%; suhu pembakaran maksimal 140ºC; lama pembaraan 1,03 menit; mortalitas rayap kayu kering 100%; pengurangan berat contoh uji 0,002%; serta derajat kerusakan kategori ringan. Katakunci: penghambat api, anti rayap, boraks, Shorea spp, Cryptotermes cynocephalus   Borax and Boric Acid Combination As Fire Retardant and Anti-termite Agents on Red Meranti Wood Abstract Woods have properties which are easy to be ignited by fire and most of them have a low natural durability. Therefore, it is required to

  20. Optical and FT Infrared spectral studies of vanadium ions in cadmium borate glass and effects of gamma irradiation.

    Science.gov (United States)

    AbdelAziz, T D; EzzElDin, F M; El Batal, H A; Abdelghany, A M

    2014-10-15

    Combined optical and infrared absorption spectra of V2O5-doped cadmium borate glasses were investigated before and after gamma irradiation with a dose of 8 Mrad (=8×10(4) Gy). The undoped base cadmium borate glass reveals a spectrum consisting of strong charge transfer UV absorption bands which are related to the presence of unavoidable contaminated trace iron impurities (mainly Fe(3+)). The V2O5-doped glasses reveal an extra band at 380nm and the high V2O5-content glass also shows a further band at about 420nm. The observed optical spectrum indicates the presence of vanadium ions mainly in the pentavalent state (d(0) configuration). The surplus band at 420nm shows that some trivalent vanadium ions are identified at high V2O5 content. The optical spectra of the glasses after gamma irradiation show small decrease of the intensity of the UV absorption which are interpreted by assuming the transformation of some Fe(3+) ions by photochemical reactions with the presence of high content (45mol%) of heavy massive CdO causing some shielding behavior. FT infrared absorption spectra of the glasses show vibrational bands due to collective presence of triangular and tetrahedral borate groups in their specific wavenumbers. The FTIR spectra are observed to be slightly affected by both the V2O5-dopants being present in modifying low percent or gamma irradiation due to the presence of high content heavy CdO. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Bone regeneration in rat calvarial defects implanted with fibrous scaffolds composed of a mixture of silicate and borate bioactive glasses.

    Science.gov (United States)

    Gu, Yifei; Huang, Wenhai; Rahaman, Mohamed N; Day, Delbert E

    2013-11-01

    Previous studies have evaluated the capacity of porous scaffolds composed of a single bioactive glass to regenerate bone. In the present study, scaffolds composed of a mixture of two different bioactive glasses (silicate 13-93 and borate 13-93B3) were created and evaluated for their response to osteogenic MLO-A5 cells in vitro and their capacity to regenerate bone in rat calvarial defects in vivo. The scaffolds, which have similar microstructures (porosity=58-67%) and contain 0, 25, 50 and 100 wt.% 13-93B3 glass, were fabricated by thermally bonding randomly oriented short fibers. The silicate 13-93 scaffolds showed a better capacity to support cell proliferation and alkaline phosphatase activity than the scaffolds containing borate 13-93B3 fibers. The amount of new bone formed in the defects implanted with the 13-93 scaffolds at 12 weeks was 31%, compared to values of 25, 17 and 20%, respectively, for the scaffolds containing 25, 50 and 100% 13-93B3 glass. The amount of new bone formed in the 13-93 scaffolds was significantly higher than in the scaffolds containing 50 and 100% 13-93B3 glass. While the 13-93 fibers were only partially converted to hydroxyapatite at 12 weeks, the 13-93B3 fibers were fully converted and formed a tubular morphology. Scaffolds composed of an optimized mixture of silicate and borate bioactive glasses could provide the requisite architecture to guide bone regeneration combined with a controllable degradation rate that could be beneficial for bone and tissue healing. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  2. Study of structural and spectroscopic behavior of Sm3+ ions in lead-zinc borate glasses containing alkali metal ions

    Science.gov (United States)

    Sasi Kumar, M. V.; Babu, S.; Rajeswara Reddy, B.; Ratnakaram, Y. C.

    2017-06-01

    High luminescence behavior of rare earth inorganic glasses have a variety of uses in the industry. In the past few decades, rare earth ions with characteristic photonics applications are being hosted by heavy metal oxide glasses. Among the rare earth ions Sm3+ ion has features which make it apt for high density optical storage. The authors of the paper have experimented to synthesize Sm3+ doped glasses. In this regard a new series of borate glasses doped with 1 mol% Sm3+ ion are developed by using melt-quenching technique. XRD, FTIR, optical absorption, luminescence techniques are used to study the various characteristics of Sm3+ ion in the present glass matrices. The XRD spectra confirms the amorphous nature of glasses. Further, the researchers have used differential thermal analysis to study the glass transition temperature. The structural groups in the prepared glasses are studied using Fourier transform infrared spectra. From the measurement of its optical absorption, three phenomenological Judd-Ofelt intensity parameters (Ω2, Ω4 and Ω6) have been computed. Based on these Judd-Ofelt intensity parameters, radiative properties such as radiative probabilities (Arad), branching ratios (β), and radiative life time (τR) are calculated. The excitation spectra of Sm3+ doped lithium heavy metal borate glass matrix is recorded under the emission wavelength of 600 nm. The emission spectra are recorded under 404 nm excitation wavelength. From various emission transitions, 4G5/2 → 6H7/2 and 4G5/2 → 6H9/2 bands could be of interest for various applications. The decay profiles of 4G5/2 level exhibit single exponential nature in all the prepared glass matrices. The potassium glass matrix exhibits higher quantum efficiency than the other glass matrices. Finally, by going through these several spectroscopic characterizations, it is concluded that the prepared Sm3+ doped lead-zinc borate glasses might be useful for visible light applications.

  3. In vitro study of improved wound-healing effect of bioactive borate-based glass nano-/micro-fibers.

    Science.gov (United States)

    Yang, Qingbo; Chen, Sisi; Shi, Honglan; Xiao, Hai; Ma, Yinfa

    2015-10-01

    Because of the promising wound-healing capability, bioactive glasses have been considered as one of the next generation hard- and soft-tissue regeneration materials. The lack of understanding of the substantial mechanisms, however, indicates the need for further study on cell-glass interactions to better interpret the rehabilitation capability. In the present work, three bioactive glass nano-/micro-fibers, silicate-based 45S5, borate-based 13-93B3 and 1605 (additionally doped with copper oxide and zinc oxide), were firstly compared for their in vitro soaking/conversion rate. The results of elemental monitoring and electron microscopic characterization demonstrated that quicker ion releasing and glass conversion occurred in borate-based fibers than that of silicate-based one. This result was also reflected by the formation speed of hydroxyapatite (HA). This process was further correlated with original boron content and surrounding rheological condition. We showed that an optimal fiber pre-soaking time (or an ideal dynamic flow rate) should exist to stimulate the best cell proliferation and migration ability. Moreover, 13-93B3 and 1605 fibers showed different glass conversion and biocompatibility properties as well, indicating that trace amount variation in composition can also influence fiber's bioactivity. In sum, our in vitro rheological module closely simulated in vivo niche environment and proved a potentially improved wound-healing effect by borate-based glass fibers, and the results shall cast light on future improvement in bioactive glass fabrication. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Effect of bioactive borate glass microstructure on bone regeneration, angiogenesis, and hydroxyapatite conversion in a rat calvarial defect model.

    Science.gov (United States)

    Bi, Lianxiang; Rahaman, Mohamed N; Day, Delbert E; Brown, Zackary; Samujh, Christopher; Liu, Xin; Mohammadkhah, Ali; Dusevich, Vladimir; Eick, J David; Bonewald, Lynda F

    2013-08-01

    Borate bioactive glasses are biocompatible and enhance new bone formation, but the effect of their microstructure on bone regeneration has received little attention. In this study scaffolds of borate bioactive glass (1393B3) with three different microstructures (trabecular, fibrous, and oriented) were compared for their capacity to regenerate bone in a rat calvarial defect model. 12weeks post-implantation the amount of new bone, mineralization, and blood vessel area in the scaffolds were evaluated using histomorphometric analysis and scanning electron microscopy. The amount of new bone formed was 33%, 23%, and 15%, respectively, of the total defect area for the trabecular, oriented, and fibrous microstructures. In comparison, the percent new bone formed in implants composed of silicate 45S5 bioactive glass particles (250-300μm) was 19%. Doping the borate glass with copper (0.4 wt.% CuO) had little effect on bone regeneration in the trabecular and oriented scaffolds, but significantly enhanced bone regeneration in the fibrous scaffolds (from 15 to 33%). The scaffolds were completely converted to hydroxyapatite within the 12week implantation. The amount of hydroxyapatite formed, 22%, 35%, and 48%, respectively, for the trabecular, oriented, and fibrous scaffolds, increased with increasing volume fraction of glass in the as-fabricated scaffold. Blood vessels infiltrated into all the scaffolds, but the trabecular scaffolds had a higher average blood vessel area compared with the oriented and fibrous scaffolds. While all three scaffold microstructures were effective in supporting bone regeneration, the trabecular scaffolds supported more bone formation and may be more promising in bone repair. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  5. Spectroscopic investigation on europium doped heavy metal borate glasses for red luminescent application

    Energy Technology Data Exchange (ETDEWEB)

    Hegde, Vinod; Wagh, Akshatha; Kamath, Sudha D. [Manipal University, Department of Physics, Manipal Institute of Technology, Manipal (India); Hegde, Hemanth [Manipal University, Department of Chemistry, Manipal Institute of Technology, Manipal (India); Vishwanath, C.S.D. [Sri Venkateswara University, Department of Physics, Tirupati (India)

    2017-05-15

    The present study explores a new borate family glasses based on 10ZnO-5Na{sub 2}O-10Bi{sub 2}O{sub 3}-(75 - x) B{sub 2}O{sub 3}-xEu{sub 2}O{sub 3} (x = 0, 0.1, 0.5, 1, 1.5, 2, 3 mol%) composition, synthesized by rapid melt quench technique. Prepared glasses were subjected to the density and refractive index measurements and their values were used to calculate other physical properties of the glass matrix as a function of Eu{sup 3+} concentration. XRD confirmed amorphous nature of the glasses. FTIR spectra in the absorption mode were recorded in the 400-4000 cm{sup -1} region to identify different functional groups in the glass matrix. Deconvoluted FTIR spectra showed increase in BO{sub 4} units with rise in europium content which confirmed the 'network strengthener' role of europium ions by creating bridging oxygens (BOs). Optical properties were investigated for their luminescence behavior through various spectroscopic techniques such as UV-Vis-NIR absorption, excitation, emission, decay profiles, and color measurements at room temperature. Lasing properties of the glasses like total radiative life time, branching ratio, emission cross section, and optical gain were obtained from the calculated Judd-Ofelt (Ω{sub 2},Ω{sub 4}) intensity parameters. From the measured values of emission, cross sections, branching ratios, life times, strong photoluminescence features, and CIE chromaticity coordinates, 0.5 mol% of Eu{sup 3+} ions doped ZnNaBiB glasses showed optimum performance and are potential candidate for red light generation at 613 nm. (orig.)

  6. Spectroscopic investigation on europium doped heavy metal borate glasses for red luminescent application

    Science.gov (United States)

    Hegde, Vinod; Wagh, Akshatha; Hegde, Hemanth; Vishwanath, C. S. Dwaraka; Kamath, Sudha D.

    2017-05-01

    The present study explores a new borate family glasses based on 10ZnO-5Na2O-10Bi2O3-(75 - x) B2O3- xEu2O3 ( x = 0, 0.1, 0.5, 1, 1.5, 2, 3 mol%) composition, synthesized by rapid melt quench technique. Prepared glasses were subjected to the density and refractive index measurements and their values were used to calculate other physical properties of the glass matrix as a function of Eu3+ concentration. XRD confirmed amorphous nature of the glasses. FTIR spectra in the absorption mode were recorded in the 400-4000 cm-1 region to identify different functional groups in the glass matrix. Deconvoluted FTIR spectra showed increase in BO4 units with rise in europium content which confirmed the `network strengthener' role of europium ions by creating bridging oxygens (BOs). Optical properties were investigated for their luminescence behavior through various spectroscopic techniques such as UV-Vis-NIR absorption, excitation, emission, decay profiles, and color measurements at room temperature. Lasing properties of the glasses like total radiative life time, branching ratio, emission cross section, and optical gain were obtained from the calculated Judd-Ofelt (Ω2,Ω4) intensity parameters. From the measured values of emission, cross sections, branching ratios, life times, strong photoluminescence features, and CIE chromaticity coordinates, 0.5 mol% of Eu3+ ions doped ZnNaBiB glasses showed optimum performance and are potential candidate for red light generation at 613 nm.

  7. Effect of CeO2 addition on electrical and optical properties of lithium borate glasses

    International Nuclear Information System (INIS)

    Gedam, R.S.; Ramteke, D.D.

    2011-01-01

    Rare earth (RE) ions play an important role in modern technology as an active ion in many optical materials. RE-doped glasses were used in many optical devices because of abundant number of the absorption and emission bands arising from the transitions between the RE elements energy levels. Among all rare earth, glasses containing CeO 2 are extensively studied for scintillating applications. Radiation length of CeO 2 containing lithium silicate glasses decreases and absorption edge in transmittance shift towards longer wavelength. In the present study an attempt has been made to verify similar results in borate containing glasses. Therefore glass series 15Li 2 O-xCeO 2 -(85''x)B 2 O 3 where x= 0.25, 0.5, 0.75, 1 mol% was prepared by conventional melt quench technique. Their electrical and optical properties have been investigated. It is observed that the conductivity of these glasses decreases while density, glass transition temperature and refractive index increases with the addition of CeO 2 . The conductivity of the glasses is mostly controlled by the activation energy. Since the lithium fraction in the present series is kept constant, the decrease in conductivity for glasses may be attributed to the reduction in the number of available vacant sites for the mobile lithium ions when boron is substituted with CeO 2 . The radiation length was determined using density values and it was found to decrease with the addition of CeO 2 . The absorption coefficient a were determined near the absorption edge of different photon energy for all glass samples and plot of (αhν) 1/2 Vs. hν (Tauc's plot) is shown. It is observed that the optical band gap energy (E g Opt ) decreases with the addition of CeO 2

  8. Composition-structure-properties relationship of strontium borate glasses for medical applications.

    Science.gov (United States)

    Hasan, Muhammad S; Werner-Zwanziger, Ulrike; Boyd, Daniel

    2015-07-01

    We have synthesized TiO2 doped strontium borate glasses, 70B2O3-(30-x)SrO-xTiO2 and 70B2 O3 -20SrO(10-x)Na2 O-xTiO2 . The composition dependence of glass structure, density, thermal properties, durability, and cytotoxicity of degradation products was studied. Digesting the glass in mineral acid and detecting the concentrations of various ions using an ICP provided the actual compositions that were 5-8% deviated from the theoretical values. The structure was investigated by means of (11)B magic angle spinning (MAS) NMR spectroscopy. DSC analyses provided the thermal properties and the degradation rates were measured by measuring the weight loss of glass disc-samples in phosphate buffered saline at 37°C in vitro. Finally, the MTT assay was used to analyze the cytotoxicity of the degradation products. The structural analysis revealed that replacing TiO2 for SrO or Na2 O increased the BO3/BO4 ratio suggesting the network-forming role of TiO2 . Thermal properties, density, and degradation rates also followed the structural changes. Varying SrO content predominantly controlled the degradation rates, which in turn controlled the ion release kinetics. A reasonable control (2-25% mass loss in 21 days) over mass loss was achieved in current study. Even though, very high concentrations (up to 5500 ppm B, and 1200 ppm Sr) of ions were released from the ternary glass compositions that saturated the degradation media in 7 days, the degradation products from ternary glass system was found noncytotoxic. However, quaternary glasses demonstrated negative affect on cell viability due to very high (7000 ppm) Na ion concentration. All the glasses investigated in current study are deemed fast degrading with further control over degradation rates, release kinetics desirable. © 2014 Wiley Periodicals, Inc.

  9. Electrically conductive borate-based bioactive glass scaffolds for bone tissue engineering applications.

    Science.gov (United States)

    Turk, Mert; Deliormanlı, Aylin M

    2017-07-01

    In this study, electrically conductive, borate-based, porous 13-93B3 bioactive glass composite scaffolds were prepared using a polymer foam replication technique. For this purpose, a slurry containing 40 vol% glass particles and 0-10 wt% graphene nanoplatelets was prepared by dispersing the particles in ethanol in the presence of ethyl cellulose. Composite scaffolds were subjected to a controlled heat treatment, in air atmosphere, to decompose the foam and sinter the glass particles into a dense network. It was found that the applied heat treatment did not influence the structure of graphene in the glass network. Graphene additions did not negatively affect the mechanical properties and enhanced the electrical conductivity of the glass scaffolds. In X-ray diffraction analysis, the crystalline peak corresponding to hydroxyapatite was observed in all the samples suggesting that all of the samples were bioactive after 30 days of immersion in simulated body fluid. However, Fourier transform infrared spectroscopy analysis and scanning electron microscope observations revealed that hydroxyapatite formation rate decreased with increasing graphene concentration especially for samples treated in simulated body fluid for shorter times. Based on the cytotoxicity assay findings, the MC3T3-E1 cell growth was significantly inhibited by the scaffolds containing higher amount of graphene compared to bare glass scaffolds. Best performance was obtained for 5 wt% graphene which yielded an enhancement of electrical conductivity with moderate cellular response and in vitro hydroxyapatite forming ability. The study revealed that the electrically conductive 13-93B3 graphene scaffolds are promising candidates for bone tissue engineering applications.

  10. Optical and thermal investigations on vanadyl doped zinc lithium borate glasses

    Directory of Open Access Journals (Sweden)

    Seema Dalal

    2015-09-01

    Full Text Available Using standard melt-quench technique, transition metal oxide (2 mol% of V2O5 doped glasses having composition xZnO·(30 − xLi2O·70B2O3 (x = 0, 2, 5, 7 and 10 are prepared. The density (D is measured using buoyancy and found to be lying between 2.21 and 2.45 g/cm3 with an increasing trend on substituting ZnO contents in place of Li2O. The theoretical optical basicity (Λth is calculated and found to increase with increasing inclusion of ZnO indicating an increase in the ionic character. The molar refraction (Rm, refractive index (nr and molar polarizability (αm are calculated and explained on the basis of structural changes. The optical absorption spectra have been used to evaluate the values of optical band gap (Eopt and band tailing parameter (B. It is observed that Eopt decreases with the increasing contents of ZnO in base glass matrix. The decrease in Eopt is an evidence of enhancement in the number of non-bridging oxygen atoms (NBOs thereby increasing the four-coordinated boron atoms. The as-quenched samples in bulk form are subjected to differential thermal analysis (DTA to assess the glass transition temperature (Tg, which is 476 °C for pure lithium borate glass. The variations suggest that the structure is being modified by the substitution of ZnO.

  11. Local distortion and EPR parameters of copper(II) in borate glasses

    Science.gov (United States)

    Kuang, Min-Quan; Wang, Li-Dan; Duan, Shu-Kai

    2017-12-01

    The EPR parameters (g and A tensors) of the paramagnetic Cu2+ sites in CaB4O7, LiCaBO3, Li2B4O7, KLiB4O7 glasses are well explained by utilizing the fourth-order perturbation formulas for 3 d9 ions in the tetragonally elongated octahedral [CuO6]10- clusters. The magnitude of the local distortion for the [CuO6]10- clusters suffering the Jahn-Teller effect is denoted by the relative elongation ratio ρ which is proportional to the ratio Δg///Δg⊥ (Δg//= g//-gs and Δg⊥ = g⊥-gs). The g isotropies giso (=(g//+2g⊥)/3) undergo an linear increase with the decline of the covalecny of the glass systems (i.e., the augment of the orbital reduction factor k). The signs of the hyperfine structure constants are determined by computing the quantitative contributions arising from the isotropic and anisotropic copper 3d-3s (4s) orbital admixtures indicated by the core polarization constant κ and the reduction factor H, respectively. The above correlations are proved to be available for analogous borate glasses doping with copper ions, e.g., MRbB4O7 (M = Li, Na and K), 90M2B4O7·9PbO·CuO (M = Li, Na and K), 10MO·30ZnO·60B2O3 (M = Mg, Ca and Sr) and xLi2O·(30-x)Na2O·69.5B2O3 (5 ≤ x ≤ 25 mol%), and all the results are discussed.

  12. Study of structural, electrical, and dielectric properties of phosphate-borate glasses and glass-ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Melo, B. M. G.; Graça, M. P. F., E-mail: mpfg@ua.pt; Prezas, P. R.; Valente, M. A. [Physics Department (I3N), Aveiro University, Campus Universitário de Santiago, Aveiro (Portugal); Almeida, A. F.; Freire, F. N. A. [Mechanics Engineering Department, Ceará Federal University, Fortaleza (Brazil); Bih, L. [Equipe Physico-Chimie la Matière Condensée, Faculté des Sciences de Meknès, Meknès (Morocco)

    2016-08-07

    In this work, phosphate-borate based glasses with molar composition 20.7P{sub 2}O{sub 5}–17.2Nb{sub 2}O{sub 5}–13.8WO{sub 3}–34.5A{sub 2}O–13.8B{sub 2}O{sub 3}, where A = Li, Na, and K, were prepared by the melt quenching technique. The as-prepared glasses were heat-treated in air at 800 °C for 4 h, which led to the formation of glass-ceramics. These high chemical and thermal stability glasses are good candidates for several applications such as fast ionic conductors, semiconductors, photonic materials, electrolytes, hermetic seals, rare-earth ion host solid lasers, and biomedical materials. The present work endorses the analysis of the electrical conductivity of the as-grown samples, and also the electrical, dielectric, and structural changes established by the heat-treatment process. The structure of the samples was analyzed using X-Ray powder Diffraction (XRD), Raman spectroscopy, and density measurements. Both XRD and Raman analysis confirmed crystals formation through the heat-treatment process. The electrical ac and dc conductivities, σ{sub ac} and σ{sub dc}, respectively, and impedance spectroscopy measurements as function of the temperature, varying from 200 to 380 K, were investigated for the as-grown and heat-treated samples. The impedance spectroscopy was measured in the frequency range of 100 Hz–1 MHz.

  13. Fabrication and characterization of poly (bisphenol A borate) with high thermal stability

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shujuan [Department of Applied Chemistry, School of Science, Xi’an Jiaotong University, Xi’an 710049 (China); Wang, Xiao [Department of Chemical Engineering, School of Chemical Engineering and Technology, Xi’an Jiaotong University, Xi’an 710049 (China); Jia, Beibei [Department of Applied Chemistry, School of Science, Xi’an Jiaotong University, Xi’an 710049 (China); Jing, Xinli, E-mail: xljing@mail.xjtu.edu.cn [Department of Applied Chemistry, School of Science, Xi’an Jiaotong University, Xi’an 710049 (China); MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi’an, 710049 (China)

    2017-01-15

    Highlights: • PBAB with excellent thermal resistance and high char yield was synthesized. • The chemical reaction of BPA with BA, and chemical structure of PBAB were studied. • PBAB show excellent thermal resistance in N{sub 2} and air atmospheres. • The thermal stability of PBAB is greatly influenced by boron content. • Boron oxide and boron carbide are formed during the pyrolysis of PBAB. - Abstract: In this work, poly (bisphenol A borate) (PBAB), which has excellent thermal resistance and a high char yield, was synthesized via a convenient A{sub 2} + B{sub 3} strategy by using bisphenol A (BPA) and boric acid (BA). The chemical reaction between BPA and BA and the chemical structure of PBAB were investigated. The results demonstrate that PBAB consists of aromatic, Ph–O–B and B–O–B structures, as well as a small number of boron hydroxyl groups and phenolic hydroxyl groups. The thermal properties of PBAB were studied by DMA and TGA. The results indicate that the glass transition temperature and char yield are gradually enhanced by increasing the boron content, where the char yield of PBAB at 800 °C in nitrogen (N{sub 2}) reaches up to 71.3%. It is of particular importance that PBAB show excellent thermal resistance in N{sub 2} and air atmospheres. By analysing the pyrolysis of PBAB, the high char yield of PBAB can be attributed to the formation of boron oxide and boron carbide at high temperatures, which reduced the release of volatile carbon dioxide and improved the thermal stability of the carbonization products. This study provides a new perspective on the design of novel boron-containing polymers and possesses significant potential for the improvement of the comprehensive performance of thermosetting resins to broaden their applicability in the field of advanced composites.

  14. Optical and spectroscopic properties of neodymium doped cadmium-sodium borate glasses

    Science.gov (United States)

    Mohan, Shaweta; Thind, Kulwant Singh

    2017-10-01

    Neodymium doped cadmium sodium borate glasses having composition xCdO-(40-x) Na2CO3-59.5H3BO3-0.5Nd2O3; x = 10, 20 and 30 mol% were prepared by conventional melt-quenching technique. X-ray diffraction studies confirmed the amorphous nature of the prepared glasses. Conventional methods were used to determine the physical properties such as density, molar volume, refractive index, and rare earth ion concentration. The Judd-Ofelt theory was applied on the optical absorption spectra of the glasses to evaluate the three phenomenological intensity parameters Ω2, Ω4 and Ω6. The calculated intensity parameters were further used to predict the radiative transition probability (A), radiative lifetime (τR) and branching ratio (βR) for the various fluorescent levels of Nd3+ ion in the prepared glass series. The effect of the compositional changes on the spectroscopic characteristics of Nd3+ ions have been studied and reported. The value of Ω2 is found to decrease with the decrease in the sodium content and the corresponding increase in the cadmium content. This can be ascribed to the changes in the asymmetry of the ligand field at the rare earth ion site and the change in rare earth oxygen (RE-O) covalency. Florescence spectra has been used to determine the peak wavelength (λp), effective line widths (Δλeff) and stimulated emission cross-section (σp) for the 4F3/2 → 4I9/2,4I11/2,4I13/2 transitions of the Nd3+ ion. The reasonably higher values of branching ratios and stimulated emission cross-section for the prepared glasses points towards the efficacy of these glasses as laser host materials. However, the glass with more sodium content is found to show better lasing properties.

  15. Theoretical study on the factors controlling the stability of the borate complexes of ribose, arabinose, lyxose, and xylose

    Czech Academy of Sciences Publication Activity Database

    Šponer, Judit E.; Sumpter, B.G.; Leszczynski, J.; Šponer, Jiří; Fuentes-Cabrera, M.

    2008-01-01

    Roč. 14, č. 32 (2008), s. 9990-9998 ISSN 0947-6539 R&D Projects: GA AV ČR(CZ) IAA400550701; GA AV ČR(CZ) IAA400040802; GA AV ČR(CZ) 1QS500040581; GA MŠk(CZ) LC06030 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : borates * density functional calculations * carbohydrates Subject RIV: AQ - Safety, Health Protection, Human - Machine Impact factor: 5.454, year: 2008

  16. Detection and Assay of Vitamin B-2 (Riboflavin) in Alkaline Borate Buffer with UV/Visible Spectrophotometry

    OpenAIRE

    Bartzatt, Ronald; Wol, Tasloach

    2014-01-01

    The detection and assay of vitamin B-2 (riboflavin) was accomplished under aqueous conditions using sodium borate buffering at pH 7.52 conditions. The absorbance spectrum of riboflavin was determined at different pH values utilizing several buffers. The buffer at pH at 7.52 is followed by accurate and sensitive assay of riboflavin by spectrophotometer at 440?nm wavelength. Where indicated an origin solution (stock) was employed by dissolving sufficient vitamin to make a stock solution of 1.40...

  17. Visible properties of Sm{sup 3+} ions in chloro-fluoro-borate glasses for reddish - orange emission

    Energy Technology Data Exchange (ETDEWEB)

    Rao, K. Venkata, E-mail: drvenkataraok@gmail.com [Department of Physics, S.B.V.R. Degree College, Badvel - 516227, A.P. (India); Babu, S.; Ratnakaram, Y. C. [Department of Physics, Sri Venkateswara University, Tirupati- 517502 (India); Rao, B. Venkata [Department of Physics, Loyola Degree College, Pulivendula- 516390, A.P. (India)

    2016-05-23

    Optical properties of different concentration (0.2, 0.4, 0.6, 0.8 and 1.0 mol %) of Sm{sup 3+} doped chloro-fluoro-borate glasses have been synthesized and discussed. Structural characterizations have been studied through XRD analysis. Spectroscopic analysis has done from absorption spectra, luminescence spectra and decay lifetime profiles. From the emission spectra, concentration quenching is observed, with increase of samarium concentration and discussed behind the phenomena. The nature of decay curve analysis was performed for the {sup 4}G{sub 5/2} level. These glasses are expected to give interesting application in the field of optics.

  18. In vitro study of improved wound-healing effect of bioactive borate-based glass nano-/micro-fibers

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Qingbo [Department of Chemistry, Missouri University of Science and Technology, Rolla, MO 65409 (United States); Center for Biomedical Science and Engineering (CBSE), Missouri University of Science and Technology, Rolla, MO 65409 (United States); Center for Single Nanoparticle, Single Cell and Single Molecule Monitoring (CS3M), Missouri University of Science and Technology, Rolla, MO 65409 (United States); Chen, Sisi [Department of Chemistry, Missouri University of Science and Technology, Rolla, MO 65409 (United States); Center for Biomedical Science and Engineering (CBSE), Missouri University of Science and Technology, Rolla, MO 65409 (United States); Shi, Honglan [Department of Chemistry, Missouri University of Science and Technology, Rolla, MO 65409 (United States); Center for Biomedical Science and Engineering (CBSE), Missouri University of Science and Technology, Rolla, MO 65409 (United States); Center for Single Nanoparticle, Single Cell and Single Molecule Monitoring (CS3M), Missouri University of Science and Technology, Rolla, MO 65409 (United States); Xiao, Hai [Department of Electrical and Computer Engineering, Clemson University, Clemson, SC 29634 (United States); Ma, Yinfa, E-mail: yinfa@mst.edu [Department of Chemistry, Missouri University of Science and Technology, Rolla, MO 65409 (United States); Center for Biomedical Science and Engineering (CBSE), Missouri University of Science and Technology, Rolla, MO 65409 (United States); Center for Single Nanoparticle, Single Cell and Single Molecule Monitoring (CS3M), Missouri University of Science and Technology, Rolla, MO 65409 (United States)

    2015-10-01

    Because of the promising wound-healing capability, bioactive glasses have been considered as one of the next generation hard- and soft-tissue regeneration materials. The lack of understanding of the substantial mechanisms, however, indicates the need for further study on cell–glass interactions to better interpret the rehabilitation capability. In the present work, three bioactive glass nano-/micro-fibers, silicate-based 45S5, borate-based 13-93B3 and 1605 (additionally doped with copper oxide and zinc oxide), were firstly compared for their in vitro soaking/conversion rate. The results of elemental monitoring and electron microscopic characterization demonstrated that quicker ion releasing and glass conversion occurred in borate-based fibers than that of silicate-based one. This result was also reflected by the formation speed of hydroxyapatite (HA). This process was further correlated with original boron content and surrounding rheological condition. We showed that an optimal fiber pre-soaking time (or an ideal dynamic flow rate) should exist to stimulate the best cell proliferation and migration ability. Moreover, 13-93B3 and 1605 fibers showed different glass conversion and biocompatibility properties as well, indicating that trace amount variation in composition can also influence fiber's bioactivity. In sum, our in vitro rheological module closely simulated in vivo niche environment and proved a potentially improved wound-healing effect by borate-based glass fibers, and the results shall cast light on future improvement in bioactive glass fabrication. - Highlights: • Bioactive glass nano-/micro-materials were effectively used for tissue wound healing. • The wound-healing effects of silicate-based 45S5, borate-based 13-93B3 and 1605 fibers were investigated. • Glass conversion rates were compared under either static or dynamic-flow modes. • Glass compositions and flow rates greatly influenced bioactivity and cell migration. • These results can

  19. The anisotropic Kerr nonlinear refractive index of the beta-barium borate (β-BaB2O4) nonlinear crystal

    DEFF Research Database (Denmark)

    Bache, Morten; Guo, Hairun; Zhou, Binbin

    2013-01-01

    We study the anisotropic nature of the Kerr nonlinear response in a beta-barium borate (β-BaB2O4, BBO) nonlinear crystal. The focus is on determining the relevant χ(3) cubic tensor components that affect interaction of type I cascaded second-harmonic generation. Various experiments in the literat......We study the anisotropic nature of the Kerr nonlinear response in a beta-barium borate (β-BaB2O4, BBO) nonlinear crystal. The focus is on determining the relevant χ(3) cubic tensor components that affect interaction of type I cascaded second-harmonic generation. Various experiments...

  20. A mechanistic study of the interaction of water-soluble borate glass with apatite-bound heterocyclic nitrogen-containing bisphosphonates.

    Science.gov (United States)

    Pramanik, Chandrani; Sood, Parveen; Niu, Li-Na; Yuan, He; Ghoshal, Sushanta; Henderson, Walter; Liu, Yaodong; Jang, Seung Soon; Kumar, Satish; Pashley, David H; Tay, Franklin R

    2016-02-01

    Long-term oral and intravenous use of nitrogen-containing bisphosphonates (N-BPs) is associated with osteonecrosis of the jaw. Although N-BPs bind strongly to bone surfaces via non-covalent bonds, it is possible for extrinsic ions to dissociate bound N-BPs from mineralized bone by competitive desorption. Here, we investigate the effects and mechanism of using an ionic cocktail derived from borate bioactive glass for sequestration of heterocyclic N-BPs bound to apatite. By employing solid-state and solution-state analytical techniques, we confirmed that sequestration of N-BPs from bisphosphonate-bound apatite occurs in the presence of the borate-containing ionic cocktail. Simulations by density functional theory computations indicate that magnesium cation and borate anion are well within the extent of the risedronate or zoledronate anion to form precipitate complexes. The sequestration mechanism is due to the borate anion competing with bisphosphonates for similar electron-deficient sites on the apatite surface for binding. Thus, application of the borate-containing ionic cocktail represents a new topical lavage approach for removing apatite-bound heterocyclic N-BPs from exposed necrotic bone in bisphosphonate-related osteonecrosis of the jaw. Long-term oral consumption and injections of nitrogen-containing bisphosphonates (N-BPs) may result in death of the jaw bone when there is traumatic injury to the bone tissues. To date, there is no effective treatment for such a condition. This work reported the use of an ionic cocktail derived from water-soluble borate glass microfibers to displace the most potent type of N-BPs that are bound strongly to the mineral component on bone surfaces. The mechanism responsible for such an effect has been identified to be cation-mediated complexation of borate anions with negatively-charged N-BPs, allowing them to be released from the mineral surface. This borate-containing cocktail may be developed into a novel topical rinse for

  1. Formation, characterization and magnetic properties of maghemite γ-Fe2O3 nanoparticles in borate glasses

    International Nuclear Information System (INIS)

    Edelman, I.S.; Ivanova, O.S.; Petrakovskaja, E.A.; Velikanov, D.A.; Tarasov, I.A.; Zubavichus, Y.V.; Trofimova, N.N.; Zaikovskii, V.I.

    2015-01-01

    Highlights: • Fe and large-ion-radius elements (Y, Bi, Pb, and Sm) co-doped borate glasses were prepared. • Maghemite, γ-Fe 2 O 3 , nanoparticles arise in the glasses as a result of the thermal treatment. • The particles structure is the same for all large-ion-radius elements used. • The particle size depends on the large-ion-radius elements nature and concentration. • The glass magnetic properties correlate with the particles size. - Abstract: A new type of nanocomposite materials based on maghemite, γ-Fe 2 O 3 , nanoparticles dispersed in borate glasses co-doped with low contents of iron together with the larger radius element combinations: Y and Bi, or Sm and Pb, or Y and Pb is studied. Nanoparticles arise as a result of heat treatment of the glasses which gives them properties characteristic of magnetically ordered substances. Transmission electron microscopy and XRD show that only one magnetic phase, namely γ-Fe 2 O 3 nanoparticles, occurs in glasses subjected to the thermal treatment at 540 °C during 24 h independently on the doping element nature. At the same time doping element and their concentrations ratio in every combination affect the particles average size and glass magnetic properties, such as magnetization temperature dependences, Faraday rotation value and electron magnetic resonance spectrum characteristics

  2. Investigation of inorganic nonlinear optical potassium penta borate tetra hydrate (PPBTH) single crystals grown by slow evaporation method

    Science.gov (United States)

    Arivuselvi, R.; Babu, P. Ramesh

    2018-03-01

    Borates family crystals were plays vital role in the field of non linear optics (NLO) due to needs of wide range of applications. In this report, NLO crystals (potassium penta borate tetra hydrate (KB5H8O12) are grown by slow evaporation method at room temperature (28° C) and studied their physical properties. The harvested single crystals are transparent with the dimension of 12 × 10 × 6 mm3 and colourless. X-ray diffraction of single crystals reveals that the grown crystal belongs to orthorhombic system with non-centrosymmetric space group Pba2. All the absorbed functional groups are present in the order of inorganic compounds expect 1688 cm-1 because of water (Osbnd H sbnd O blending) molecule present in the pristine. Crystals show transparent in the entire visible region with 5.9 eV optical band gap and also it shows excellence in both second and third order nonlinear optical properties. Crystals can withstand upto 154 °C without any phase changes which is observed using thermal (TGA/DTA) analysis.

  3. Evaluation of an injectable bioactive borate glass cement to heal bone defects in a rabbit femoral condyle model.

    Science.gov (United States)

    Cui, Xu; Huang, Wenhai; Zhang, Yadong; Huang, Chengcheng; Yu, Zunxiong; Wang, Lei; Liu, Wenlong; Wang, Ting; Zhou, Jie; Wang, Hui; Zhou, Nai; Wang, Deping; Pan, Haobo; Rahaman, Mohamed N

    2017-04-01

    There is a need for synthetic biomaterials to heal bone defects using minimal invasive surgery. In the present study, an injectable cement composed of bioactive borate glass particles and a chitosan bonding solution was developed and evaluated for its capacity to heal bone defects in a rabbit femoral condyle model. The injectability and setting time of the cement in vitro decreased but the compressive strength increased (8±2MPa to 31±2MPa) as the ratio of glass particles to chitosan solution increased (from 1.0gml -1 to 2.5gml -1 ). Upon immersing the cement in phosphate-buffered saline, the glass particles reacted and converted to hydroxyapatite, imparting bioactivity to the cement. Osteoblastic MC3T3-E1 cells showed enhanced proliferation and alkaline phosphatase activity when incubated in media containing the soluble ionic product of the cement. The bioactive glass cement showed a better capacity to stimulate bone formation in rabbit femoral condyle defects at 12weeks postimplantation when compared to a commercial calcium sulfate cement. The injectable bioactive borate glass cement developed in this study could provide a promising biomaterial to heal bone defects by minimal invasive surgery. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Microwave Absorption of Barium Borosilicate, Zinc Borate, Fe-Doped Alumino-Phosphate Glasses and Its Raw Materials

    Directory of Open Access Journals (Sweden)

    Ashis Kumar Mandal

    2015-05-01

    Full Text Available This study presents microwave absorption of raw materials used in barium borosilicate, Fe-doped alumina phosphate and zinc borate glass. Microwave absorption was investigated for the raw materials SiO2, Na2CO3, BaCO3, BPO4, Al(PO33, Mg(PO32, Al(OH3, TiO2. The study shows that SiO2 could be heated directly above 1000 °C within 30 min at 1.5 kW microwave output (MW power and 0.8 kW MW power is necessary to initiate heating (from 260 °C. Microwave heating of material with low dielectric loss has been investigated by increasing MW power. Microwave absorption of above glass systems has also been investigated. Dielectric properties such as loss tangent of glass as a function of temperature are presented. Glass melting under direct microwave heating was demonstrated for the studied glass systems. Temperature-Microwave power-Time (T-P-t profiles for the three glasses indicate maximum MW output power ~1 kW, 0.65 kW and ~1 kW for barium borosilicate, zinc borate glass and alumino-phosphate glass for 60 g glass melting.

  5. Simultaneous pollutant removal and electricity generation in denitrifying microbial fuel cell with boric acid-borate buffer solution.

    Science.gov (United States)

    Chen, Gang; Zhang, Shaohui; Li, Meng; Wei, Yan

    2015-01-01

    A double-chamber denitrifying microbial fuel cell (MFC), using boric acid-borate buffer solution as an alternative to phosphate buffer solution, was set up to investigate the influence of buffer solution concentration, temperature and external resistance on electricity generation and pollutant removal efficiency. The result revealed that the denitrifying MFC with boric acid-borate buffer solution was successfully started up in 51 days, with a stable cell voltage of 205.1 ± 1.96 mV at an external resistance of 50 Ω. Higher concentration of buffer solution favored nitrogen removal and electricity generation. The maximum power density of 8.27 W/m(3) net cathodic chamber was obtained at a buffer solution concentration of 100 mmol/L. An increase in temperature benefitted electricity generation and nitrogen removal. A suitable temperature for this denitrifying MFC was suggested to be 25 °C. Decreasing the external resistance favored nitrogen removal and organic matter consumption by exoelectrogens.

  6. Thermoluminescence dosimetry properties and kinetic parameters of lithium potassium borate glass co-doped with titanium and magnesium oxides

    International Nuclear Information System (INIS)

    Hashim, S.; Alajerami, Y.S.M.; Ramli, A.T.; Ghoshal, S.K.; Saleh, M.A.; Abdul Kadir, A.B.; Saripan, M.I.; Alzimami, K.; Bradley, D.A.; Mhareb, M.H.A.

    2014-01-01

    Lithium potassium borate (LKB) glasses co-doped with TiO 2 and MgO were prepared using the melt quenching technique. The glasses were cut into transparent chips and exposed to gamma rays of 60 Co to study their thermoluminescence (TL) properties. The TL glow curve of the Ti-doped material featured a single prominent peak at 230 °C. Additional incorporation of MgO as a co-activator enhanced the TL intensity threefold. LKB:Ti,Mg is a low-Z material (Z eff =8.89) with slow signal fading. Its radiation sensitivity is 12 times lower that the sensitivity of TLD-100. The dose response is linear at doses up to 10 3 Gy. The trap parameters, such as the kinetics order, activation energy, and frequency factor, which are related to the glow peak, were determined using TolAnal software. - Highlights: • Lithium potassium borate glass doped with Ti and Mg was prepared. • The material is close to soft tissues in terms of Zeff. • The radiation sensitivity is about 12 times lower than that of TLD-100. • The signal fades about 8% in 10 days and 17% in 3 months

  7. On the Electrochemical Behavior of PVD Ti-Coated AISI 304 Stainless Steel in Borate Buffer Solution

    Science.gov (United States)

    Fattah-alhosseini, Arash; Elmkhah, Hassan; Attarzadeh, Farid Reza

    2017-04-01

    This work aims at studying the electrochemical behavior of annealed pure titanium (Ti) and nano-structured (NS) Ti coating in borate buffer solutions. Cathodic arc evaporation was successfully applied to deposit NS Ti coating. Samples were characterized by means of scanning electron microscope and x-ray diffraction. Potentiodynamic polarization tests, electrochemical impedance spectroscopy, and Mott-Schottky analysis were employed to discuss the electrochemical behavior of samples thoroughly. Electrochemical measurements showed that the deposited NS Ti coating offers a superior passivity in borate buffer solutions of pH 9.0 and 9.5. Mott-Schottky analysis revealed that all passive films are of n-type semiconducting nature in these alkaline solutions and the deposition process did not alter the semiconducting type of passive films formed on samples. Additionally, this analysis showed that the NS Ti coating possessed lower levels of donor densities. Finally, all electrochemical tests showed that passive behavior of the NS Ti samples was superior, mainly due to the formation of thicker and less defective passive films.

  8. Detecting non-bridging oxygens: non-resonant inelastic X-ray scattering in crystalline lithium borates.

    Science.gov (United States)

    Lelong, Gérald; Radtke, Guillaume; Cormier, Laurent; Bricha, Hanane; Rueff, Jean-Pascal; Ablett, James M; Cabaret, Delphine; Gélébart, Frédéric; Shukla, Abhay

    2014-10-20

    Probing the local environment of low-Z elements, such as oxygen, is of great interest for understanding the atomic-scale behavior in materials, but it requires experimental techniques allowing it to work with versatile sample environments. In this paper, the local environment of lithium borate crystals is investigated using non-resonant inelastic X-ray scattering (NRIXS) at energy losses corresponding to the oxygen K-edge. Large variations of the spectral features are observed close to the edge onset in the 535-540 eV energy range when varying the Li2O content. Calculations allow identification of contributions associated with bridging oxygen (BO) and non-bridging oxygen (NBO) atoms. The main result resides in the observed core-level shift of about 1.7 eV in the spectral signatures of the BO and NBO. The clear signature at 535 eV in the O K-edge NRXIS spectrum is thus an original way to probe the presence of NBOs in borates, with the great advantage of making possible the use of complex environments such as a high-pressure cell or high-temperature device for in situ measurements.

  9. Thermal, structural and spectroscopic properties of Pr3+-doped lead zinc borate glasses modified by alkali metal ions

    Directory of Open Access Journals (Sweden)

    M.V. Sasi kumar

    2017-07-01

    Full Text Available This paper offers a study on Pr3+-doped alkali and mixed-alkali borate glasses prepared by the melt quenching technique and characterized by thermal, structural and spectroscopic studies. The amorphous nature of the glassy systems was identified based on X-ray diffraction. The thermal behaviour of glasses was studied using differential thermal analysis (DTA. The functional groups contained in the glasses were identified by Fourier transform infrared spectroscopy (FTIR. Spectral intensities were evaluated from the absorption spectra and used for calculating J–O intensity parameters, Ωλ (λ = 2, 4 and 6. Further, these parameters were used for calculating different radiative properties. The best radiative state was identified as the laser transition state among the various states. Emission analysis was performed for this state by calculating the branching ratios and stimulated emission cross sections (σp for all the prepared glasses. These studies suggest that borate glasses are useful for visible fluorescence.

  10. Spectroscopy and energy transfer in lead borate glasses doubly doped with Tm3+ and Dy3+ ions

    Science.gov (United States)

    Górny, Agata; Sołtys, Marta; Pisarska, Joanna; Pisarski, Wojciech A.

    2018-03-01

    Lead borate glasses singly and doubly doped with Tm3+ and Dy3+ were prepared by traditional melt-quenching technique. The emission spectra of rare earths in studied glass systems were registered under different excitation wavelengths. The observed emission bands are located in the visible spectral region. They correspond to 1D2 → 3F4 (blue) and 1G4 → 3H6 (blue) transitions of Tm3+ as well as 4F9/2 → 6H15/2 (blue), 4F9/2 → 6H13/2 (yellow) and 4F9/2 → 6H11/2 (red) transitions of Dy3+. Moreover, the energy transfer process from Tm3+ to Dy3+ was observed. The luminescence bands originating to characteristic transitions of thulium and dysprosium ions are present on emission spectra under direct excitation of Tm3+. Luminescence lifetimes for the excited states of Tm3+ and Dy3+ ions in lead borate glass were also determined based on decay measurements. The luminescence intensities and lifetimes depend significantly on the relative concentrations of the optically active dopants.

  11. Physical and spectroscopic studies of Cr{sup 3+} doped mixed alkaline earth oxide borate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Samdani, E-mail: samdanimohd82@gmail.com [Department of Engineering, Salalah College of Technology, Salalah (Oman); Ramadevudu, G. [Department of Physics, Vasavi College of Engineering, Ibrahimbagh, Hyderabad 500031, Telangana (India); Chary, M. Narasimha; Shareefuddin, Md. [Department of Physics, Osmania University, Hyderabad 500007, Telangana (India)

    2017-01-15

    A series of mixed alkaline earth oxide glasses xMgO-(30-x)BaO-69.8B{sub 2}O{sub 3}-0.2Cr{sub 2}O{sub 3} were prepared and studied using electron paramagnetic resonance (EPR), optical absorption, Raman spectroscopy and photoluminescence experimental techniques. The optical absorption spectra revealed the characteristic octahedral symmetry of Cr{sup 3+}ions through three broad band transitions {sup 4}A{sub 2g}(F)→ {sup 4}T{sub 2g}(F), {sup 4}A{sub 2g}(F)→ {sup 4}T{sub 1g}(F), and {sup 4}A{sub 2g}(F)→ {sup 2}T{sub 1g}(P). The crystal field (Dq) and Racah parameters (B and C), the optical band gap and Urbach energies of the glass samples were also reported along with the physical properties like density and molar volume. In the EPR spectra three resonance signals corresponding to Cr3+ ions were observed. A broad signal with g = 5.110 was observed which belongs to the isolated Cr3+ centers localized in the strongly distorted octahedral (rhombic) sites of the glass network, a narrow signal (g = 1.960) corresponding to the Cr{sup 3+} centers in the weekly distorted (cubic) sites of the glass network, and a third very broad signal (g = 2.210) was also observed corresponding to Cr{sup 3+}- Cr{sup 3+} paired centers coupled by magnetic dipolar interaction. Another resonance signal with effective value g ≈ 4.220 was attributed to Fe{sup 3+} ions impurity. The number of spins (N) participating in the resonance and susceptibility (χ) values at room temperature were reported and their values varied in a non-linear manner with the composition exhibiting mixed oxide effect. The estimated molecular bonding coefficients (α) values indicated stronger ionic contribution. The Raman spectral investigations were carried out. The Photoluminescence spectra bands near 690 and 750 nm correspond to the Cr{sup 3+} centers in high and low field sites respectively. - Highlights: • Spectroscopic studies were made on alkaline earth borate glasses. • Three resonance signals

  12. TL and OSL studies on lithium borate single crystals doped with Cu and Ag

    International Nuclear Information System (INIS)

    Rawat, N.S.; Kulkarni, M.S.; Tyagi, M.; Ratna, P.; Mishra, D.R.; Singh, S.G.; Tiwari, B.; Soni, A.; Gadkari, S.C.; Gupta, S.K.

    2012-01-01

    Lithium borate (LBO) single crystals doped with Cu and Ag (0.25 mol% each) (Li 2 B 4 O 7 :Cu,Ag) are grown by the Czochralski method. The thermoluminescence readout on Li 2 B 4 O 7 :Cu,Ag crystals showed three glow peaks at∼375, 441 and 516 K for the heating rate of 1 K/s. The thermoluminescence sensitivity of the grown Li 2 B 4 O 7 :Cu,Ag single crystals is found to be 5 times TLD-100 and a linear dose response in the range 1 mGy to 1 kGy. The glow curve deconvolution reveals nearly first order kinetics for all the three peaks with trap depths 0.77, 1.25 and 1.34 eV respectively and corresponding frequency factors 1.6×10 9 , 1.3×10 13 and 6.8×10 11 s −1 . The continuous wave optically stimulated luminescence (CW-OSL) measurements were performed on the LBO:Cu,Ag single crystals using blue light stimulation. The traps responsible for the three thermoluminescence peaks in Li 2 B 4 O 7 :Cu,Ag are found to be OSL sensitive. The qualitative correlation between TL peaks and CW-OSL response is established. The photoluminescence studies show that in case of co-doping of Ag in LBO:Cu the emission at 370 nm in Cu states dominates over the transitions in Ag states implying doping of Ag plays a role as sensitizer when co-doped with Cu and increases overall emission. - Highlights: ► Growth of crack free single crystals of Li2B4O7 :Cu and Ag. ► Study of TL and OSL parameters for Li2B4O7 :Cu and Ag. ► Correlation of OSL with TL peaks. ► Optimization of OSL readout time with respect to residual TL.

  13. Structural and luminescence properties of samarium doped lead alumino borate glasses

    Science.gov (United States)

    Mohan, Shaweta; Kaur, Simranpreet; Singh, D. P.; Kaur, Puneet

    2017-11-01

    The study reports the effect of samarium concentration on the physical, structural and spectroscopic characteristics of samarium doped lead alumino borate glasses having composition 20PbO-(10-x)Al2O3-70B2O3-xSm2O3; x = 0.1, 0.5, 1.0 and 2.0 mol %. The glasses were fabricated by conventional melt-quenching technique and then characterized by XRD, FTIR, optical absorption and fluorescence spectra. X-ray diffraction studies confirmed the amorphous nature of the prepared glasses. FTIR spectra indicate the presence of BO3, BO4, AlO6 and a few other structural groups. Various physical properties such as density, molar volume, refractive index, rare earth ion concentration, boron-boron distance and polarizability etc. were determined using conventional methods and standard formulae. The Judd-Ofelt theory was applied on the optical absorption spectra of the glasses to evaluate the three phenomenological intensity parameters Ω2, Ω4 and Ω6. The value of Ω2 was found to be highest for glass with 1 mol% Sm2O3 and attributed to the asymmetry of the ligand field at the rare earth ion site and the rare earth oxygen (Sm-O) covalency. The calculated intensity parameters and fluorescence spectra were further used to predict the radiative transition probability (A), radiative lifetime (τR), branching ratio (βR), peak wavelength (λp), effective line widths (Δλeff) and stimulated emission cross-section (σ) for the characteristic 4G5/2 → 6H5/2, 6H7/2 and 6H9/2 transitions of the Sm3+ ion. Concentration quenching was observed for 2 mol% concentration of Sm2O3 and ascribed to energy transfer through various cross-relaxation channels between Sm3+ ions. Reasonably high values of branching ratios and stimulated emission cross-section for the prepared glasses points towards their utility in the development of visible lasers emitting in the reddish-orange spectral region. However, the glass with 1 mol% Sm2O3 was found to show better radiative properties.

  14. Physical and optical studies in mixed alkali borate glasses with three types of alkali ions

    International Nuclear Information System (INIS)

    Samee, M.A.; Awasthi, A.M.; Shripathi, T.; Bale, Shashidhar; Srinivasu, Ch.; Rahman, Syed

    2011-01-01

    Research highlights: → We report, for the first time, the mixed alkali effect in the (40-x)Li 2 O-xNa 2 O-10K 2 O-50B 2 O 3 glasses through optical properties, density and modulated DSC studies. → Optical band gap (E opt ) and Urbach energy (ΔE) have been evaluated. → The values of E opt and ΔE show non-linear behavior with compositional parameter showing the mixed alkali effect. → The glass stability S is observed to be less which may be important for the present glasses as promising material for non-optical applications. - Abstract: So far only a handful of publications have been concerned with the study of the mixed alkali effect in borate glasses containing three types of alkali ions. In the present work, the mixed alkali effect (MAE) has been investigated in the glass system (40-x)Li 2 O-xNa 2 O-10K 2 O-50B 2 O 3 . (0 ≤ x ≤ 40 mol%) through density and modulated DSC studies. The density and glass transition temperature of the present glasses varies non-linearly exhibiting mixed alkali effect. The glass stability is observed to be less which may be important for the present glasses as promising material for non-optical applications. We report, for the first time, the mixed alkali effect in the present glasses through optical properties. From the absorption edge studies, the values of indirect optical band gap (E opt ), direct optical band gap and Urbach energy (ΔE) have been evaluated. The values of E opt and ΔE show non-linear behavior with compositional parameter showing the mixed alkali effect. The average electronic polarizability of oxide ions α O 2- , optical basicity Λ, and Yamashita-Kurosawa's interaction parameter A have been examined to check the correlations among them and bonding character. Based on good correlation among electronic polarizability of oxide ions, optical basicity and interaction parameter, the present Li 2 O-Na 2 O-K 2 O-B 2 O 3 glasses are classified as normal ionic (basic) oxides.

  15. Ordered and disordered models of local structure around Ag cations in silver borate glasses based on x-ray absorptio n near-edge structure spectroscopy

    Czech Academy of Sciences Publication Activity Database

    Šipr, Ondřej; Dalba, G.; Rocca, F.

    2004-01-01

    Roč. 69, - (2004), 134201/1-134201/16 ISSN 0163-1829 R&D Projects: GA ČR GA202/02/0841 Institutional research plan: CEZ:AV0Z1010914 Keywords : disordered systems * structural analysis * XANES * silver * borate glass es Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.075, year: 2004

  16. Geochemical analysis of brine samples for exploration of Borate deposits in the South of Sabzevar

    Directory of Open Access Journals (Sweden)

    Mahdi Bemani

    2016-07-01

    Full Text Available Introduction Mohammad-abad Oryan is the only potential source of borate in the North-east of Iran located in 50 km South of Sabzevar. The area is located in tuff marl, tuffaceous marl, volcanic braccia and tuff braccia structures. Remote sensing techniques, geological studies and integration of this data in GIS were applied in an area of about 600 square kilometers to locate the promising areas of borate mineralization for detailed studies (Bemani, 2012. The aim of this detailed geochemical study is to confine the anomaly areas for exploratory drilling and trenching. Materials and methods Field studies were carried out in 9 geological traverses, mainly in Tonakar and Borje Kharkan area and 126 brine samples were taken from hydrothermal springs and 13 rock samples were taken from trenches. All the samples were analyzed for four elements, including B, K, Li and Mg. In order to determine the threshold quantities of the samples and isolation of anomaly, the data were analyzed using statistical methods including classical statistics, fractal geometry and EDA methods (Bemani, 2012. Result Initial data analysis showed that there were no censored data. Also, by applying statistical hypothesis testing, no significant relation was observed between the elements in the two areas (except for Li. Therefore, all the statistical analyses were carried out separately. After outlier correction, based on the amount of skewedness and histograms and probability plots of different elements, it became clear that none of the elements in the raw data distribution were normal and required to be transformed to be close to normal. In this study, logarithmic and three-parameter logarithm transformation were used in order to normalize the data . Based on the mean values, standard deviation of the normalized data, and background value and threshold, probable and possible anomalies were obtained and geochemical anomaly maps were drawn to identify the promising areas. With the

  17. Effect of zinc-borate glass addition on the thermal properties of the cordierite/Al2O3 composites containing nano-sized spinel crystal.

    Science.gov (United States)

    Jo, Sinae; Kang, Seunggu

    2013-11-01

    Low-melting zinc-borate glass was added to the cordierite/Al2O3 composite in order to improve the sintering facility of Al2O3 and formation of nano-sized spinel crystal of high thermal conductivity. Increasing the ZnO/B2O3 ratio in the zinc-borate glass increased the ZnAl2O4 spinel and decreased the Al4B2O9 crystal peak intensities in X-ray diffraction pattern. The XRD peak intensities of the ZnAl2O4 spinel and Al4B2O9 crystals in the specimen containing 10 wt% zinc-borate glass (10G series) are higher than that of the specimen containing 5 wt% zinc-borate glass (5G series). The microstructures of most 10G series specimens had the flower-shaped crystal which was composed of 50 nm wide and 250 nm long needle-like crystals and identified as ZnAl2O4 spinel phase. The thermal conductivity of the 10G series specimen was higher than that of the 5G series in any ZnO/B2O3 ratio due to the formation of plenty of nano-sized ZnAl2O4 spinel of high thermal conductivity. Particularly, the thermal conductivity of the cordierite/Al2O3 composite containing 10 wt% zinc-borate glass of ZnO/B2O3 weight ratio = 1.5 was 3.8 W/Km which is much higher than that of the published value (3.0 W/Km).

  18. DFT-Based Comparative Study about the Influence of Fluorine and Hydroxyl Anions on Opto-Electric Properties of Borate Crystals: Choice for Better Anion.

    Science.gov (United States)

    Bashir, Beenish; Zhang, Bingbing; Lee, Ming-Hsien; Pan, Shilie; Yang, Zhihua

    2017-05-15

    Replacing hydroxyl anions OH¯ by fluorine anions F¯ in borates can cause the blue shift of the UV cutoff edge and also exhibits apparent differences in nonlinear optical (NLO) properties. To clarify the intrinsic difference between OH¯ anions and F¯ anions, several typical borates with different types of cations (p-cations with lone-pair electrons, trivalent rare-earth, and alkaline earth metals) have been studied. The theoretical studies reveal that the blue shift in the band gap of borates with fluorine as compared to those with hydroxyl can be assumed to be the result of weaker interaction of the cation-fluoride (La/Bi/B-F) bonds compared to that of the cation-oxygen and hydroxyl bonds. NLO properties are found to have the order of BiB 2 O 4 F > BiB 2 O 4 (OH)> LaB 2 O 4 F ≈ LaB 2 O 4 (OH). The large difference can be attributed mainly to the stereochemical activity of the lone pair (SCALP) effect of the Bi cations and the special BO 3 F with strong anisotropy as compared to the BO 4 group. The energy spanning of F-2p orbitals is more extended in BiB 2 O 4 F as compared to LaB 2 O 4 F, Sr 3 B 6 O 11 F 2 , and Ba 3 B 6 O 11 F 2 due to the bonding of Bi/B-F, which indicates F-2p orbitals have more chance to overlap with surrounding atoms and enhance the polarizability in all systems. Moreover, the degree of SCALP of the Bi cations is apparently activated by the introduction of the F¯ anions, which causes an obvious enhancement in NLO properties in bismuth borates with F¯. These investigations will help us to classify the solid-state chemistry of F¯ and OH¯ anions in borate systems with different types of metal cations.

  19. Multimodal emissions from Tb3+/Yb3+ co-doped lithium borate glass: Upconversion, downshifting and quantum cutting

    International Nuclear Information System (INIS)

    Bahadur, A.; Yadav, R.S.; Yadav, R.V.; Rai, S.B.

    2017-01-01

    This paper reports the optical properties of Tb 3+ /Yb 3+ co-doped lithium borate (LB) glass prepared by melt quench method. The absorption spectrum of the Yb 3+ doped LB glass contains intense NIR band centered at 976 nm due to 2 F 7/2 → 2 F 5/2 transition. The emission spectra of the prepared glasses have been monitored on excitation with 266, 355 and 976 nm. The Yb 3+ doped glass emits a broad NIR band centered at 976 nm whereas the Tb 3+ doped glass gives off visible bands on excitations with 266 and 355 nm. When the Tb 3+ and Yb 3+ ions are co-doped together, the emission intensity in the visible region decreases whereas it increases in the NIR region significantly. The increase in the emission intensity in the NIR region is due to efficient cooperative energy transfer (CET) from Tb 3+ to Yb 3+ ions. The quantum cutting efficiency for Tb 3+ /Yb 3+ co-doped glass has been calculated and compared for 266 and 355 nm excitations. The quantum cutting efficiency is larger for 355 nm excitation (137%). The Tb 3+ /Yb 3+ co-doped LB glass also emits upconverted visible bands on excitation with 976 nm. The mechanisms involved in the energy transfer have been discussed using schematic energy level diagram. The Tb 3+ /Yb 3+ co-doped LB glass may be used in the optical devices and in solar cell for solar spectral conversion and behaves as a multi-modal photo-luminescent material. - Graphical abstract: The Tb 3+ /Yb 3+ co-doped lithium borate (LB) glass prepared by melt quench method emits upconverted visible emissions through upconversion CET from Yb 3+ to Tb 3+ ions and quantum cutting emissions through downconversion CET from Tb 3+ to Yb 3+ ions. Therefore, the Tb 3+ /Yb 3+ co-doped LB glass may find applications in optical devices and solar cell and behaves as a multi-modal photo-luminescent material. - Highlights: • The Tb 3+ /Yb 3+ co-doped lithium borate (LB) glass prepared by melt quench method. • The Tb 3+ /Yb 3+ co-doped glass gives QC emissions upon 266 and

  20. Physical and electrochemical properties of quaternary ammonium bis(oxalato)borates and their application to electric double-layer capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Nanbu, Noritoshi [Department of Nanochemistry, Faculty of Engineering, Tokyo Polytechnic University, Faculty of Engineering, Tokyo, 1583 Iiyama, Atsugi, Kanagawa 243-0297 (Japan)]. E-mail: nanbu@nano.t-kougei.ac.jp; Ebina, Takahito [Department of Nanochemistry, Faculty of Engineering, Tokyo Polytechnic University , 1583 Iiyama, Atsugi, Kanagawa 243-0297 (Japan); Uno, Hiroyuki [Department of Nanochemistry, Faculty of Engineering, Tokyo Polytechnic University, 1583 Iiyama, Atsugi, Kanagawa 243-0297 (Japan); Ishizawa, Saki [Department of Nanochemistry, Faculty of Engineering, Tokyo Polytechnic University, 1583 Iiyama, Atsugi, Kanagawa 243-0297 (Japan); Sasaki, Yukio [Department of Nanochemistry, Faculty of Engineering, Tokyo Polytechnic University, 1583 Iiyama, Atsugi, Kanagawa 243-0297 (Japan)

    2006-12-01

    The use of nonhalogenated electrolyte salts for electrochemical devices is very important from the point of view of safety and cost. We have investigated the physical and electrochemical properties of a series of quaternary ammonium bis(oxalato)borates (QABOBs) and the performance of electric double-layer capacitors (EDLCs). The mass and van der Waals volume of BOB{sup -} are higher and larger than those of BF{sub 4} {sup -}. The mass densities, viscosities, and surface tensions of propylene carbonate (PC) solutions containing the QABOBs are higher than those obtained for tetraethylammonium tetrafluoroborate (TEABF{sub 4}), and the electric conductivities become lower. However, the electrochemical voltage windows measured with an activated carbon electrode and the gravimetric capacitances of 2025-type coin cells are comparable to those obtained for the PC solutions containing the TEABF{sub 4}.

  1. Physical and optical absorption studies of Fe{sup 3+} - ions doped lithium borate glasses containing certain alkaline earths

    Energy Technology Data Exchange (ETDEWEB)

    Bhogi, Ashok [VNR Vignana Jyothi Institute of Engineering and Technology, Hyderabad, Telangana (India); Kumar, R. Vijaya [School of Physics, University of Hyderabad, Hyderabad, Telangana (India); Kistaiah, P., E-mail: pkistaiah@yahoo.com [Department of Physics, Osmania University, Hyderabad, Telangana (India)

    2016-05-23

    Iron ion doped lithium borate glasses with the composition 15RO-25Li{sub 2}O-59B{sub 2}O{sub 3}-1Fe{sub 2}O{sub 3} (where R= Ca, Sr and Ba) have been prepared by the conventional melt quenching technique and characterized to investigate the physical and optical properties using XRD, density, molar volume and UV-Visible spectroscopy. The optical absorption spectra exhibit a band at around 460 nm which is assigned to {sup 6}A{sub 1g}(S) → 4E{sub g} (G) of Fe{sup 3+} ions with distorted octahedral symmetry. From ultraviolet absorption edges, the optical band gap and Urbach energies have been evaluated. The effect of alkaline earths on these properties is discussed.

  2. Effect of Co(2+) and Ni(2+)-doped zinc borate nano crystalline powders by co-precipitation method.

    Science.gov (United States)

    Shim, Jaesool; Venkata Reddy, Ch; Sarma, G V S S; Narayana Murthy, P; Ravikumar, R V S S N

    2015-05-05

    A simple co-precipitation method has been used for the synthesis of Co(2+) and Ni(2+)-doped zinc borate nanopowders. X-ray diffraction (XRD), Fourier transform infrared (FT-IR), UV/Vis absorption, Scanning electron microscope (SEM) with EDS and photoluminescence (PL) spectroscopies techniques has been employed for their characterization. Powder X-ray diffraction data reveals that the crystal structure belongs to monoclinic for both as-prepared samples. SEM images showed surface morphology of the prepared samples. Optical absorption spectra showed the characteristic bands of doped ions in octahedral site symmetry. From the optical absorption data crystal field and inter-electronic repulsion parameters are evaluated. The FT-IR spectra showed the characteristic vibrational bands related to ZnO, BO3 and BO4 molecules. Photoluminescence spectra exhibited the emission bands in ultraviolet and blue regions. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Broadly tunable, beta-barium-borate-based, pulsed optical parametric oscillators and their potential applications in medicine

    Science.gov (United States)

    Sobey, Mark S.; Clark, Jim; Johnson, Bertram C.

    1995-05-01

    With the recent availability of Beta Barium Borate (BBO) crystals in useful sizes at acceptable market prices, the promise of Optical Parametric Oscillators (OPOs) becoming practical tunable systems is finally being realized. Wavelength coverage from such systems extends from 420 nm to over 2400 nm when pumped in the UV. For medical applications their usage will be limited in the near term to low repetition rates (suitable for selective absorption applications in medicine such as colored tattoo removal or treating vascular lesions. For such high energy devices peak powers necessitate the use of articulating arms for beam delivery. For high repetition rate systems, energy outputs will be in the range of 100 to 500 (mu) J at kHz frequencies (up to 1 W average power). Peak powers are low enough that fiber optic delivery is possible. These systems may find selective absorption applications in ophthalmology.

  4. Synthesis and characterization of γ-irradiated cadmium-borate glasses doped V2O5

    Directory of Open Access Journals (Sweden)

    S. Bahammam

    Full Text Available In this work, we study the relationship between the optical and magnetic properties for the irradiated and unirradiated V2O5-doped cadmium borate glasses and examined their optical band energy that has compromise of non-bridging oxygen (NBO and bridging oxygen (BO, V3+, V4+ and V5+, and BO3 units and BO4 units. The induced defects created by γ-rays were characterized by optical and EPR spectroscopy. The dependability of the defects and the tendency for recombination or conversion of the defects besides the environment of optically dynamic V centers was also discussed. It is concluded that the development of both optical and magnetic intensity is related to V4+ ions at tetrahedral sites whereas the decrease in their intensity is recognized to the ligand-metal charge transfer transitions of V4+ ions coupled to V5+. The optical band gap energy (Eg has been observed to decrease with increasing either V2O5 content or γ-doses. High γ-dose reduces the values of the allowed direct optical band gap Eg of 0.5 Mol% V2O5 glass up to 45 kGy after which Eg increases, but remain lower than that of un-irradiated glass. Borate glasses under this study showed linear optical absorption response over the dose range of 5–80 kG. Fading under dark and room light in 2 h after exposure in the course of 30 days have been studied in detail and presented. Our results and findings indicate that, the investigated samples may be seemed to be a good candidate for radiation processing purposes. Keywords: CdO-B2O3 glass, V2O5, Transmission, Absorption, EPR, γ-Irradiation

  5. Thermoluminescence (TL dosimeter of dysprosium doped strontium borate glass for different glass modifiers (Na, Li, Ca subjected from 1 to 9 Gy doses

    Directory of Open Access Journals (Sweden)

    Hamzah S. A.

    2017-01-01

    Full Text Available This article reports TL response for different glass modifier and doping concentration. Alkali oxides (Na2O and Li2O and alkali earth oxide (CaO will be used as a glass modifier for strontium borate based glass. The samples were prepared by melt quenching technique. Dy2O3 concentrations ranging from 0.00 to 0.70 mol% and exposure doses of 1 to 9 Gy will be varied. All glass samples exhibit the prominent peak temperature positioned at 186 oC to 232 oC. From all the samples, one of the samples shows an excellent linearity dose response, higher TL and show good reproducibility after 5 cycles exposure which is sodium strontium borate doped with 0.1 mol% Dy2O3 (optimum concentration.

  6. Thermoluminescence (TL) dosimeter of dysprosium doped strontium borate glass for different glass modifiers (Na, Li, Ca) subjected from 1 to 9 Gy doses

    Science.gov (United States)

    Hamzah, S. A.; Saeed, M. A.; Wagiran, H.; Hashim, I. H.

    2017-10-01

    This article reports TL response for different glass modifier and doping concentration. Alkali oxides (Na2O and Li2O) and alkali earth oxide (CaO) will be used as a glass modifier for strontium borate based glass. The samples were prepared by melt quenching technique. Dy2O3 concentrations ranging from 0.00 to 0.70 mol% and exposure doses of 1 to 9 Gy will be varied. All glass samples exhibit the prominent peak temperature positioned at 186 oC to 232 oC. From all the samples, one of the samples shows an excellent linearity dose response, higher TL and show good reproducibility after 5 cycles exposure which is sodium strontium borate doped with 0.1 mol% Dy2O3 (optimum concentration).

  7. Spectroscopy and energy transfer in lead borate glasses doubly doped with Dy(3)(+)-Tb(3+) and Tb(3)(+)-Eu(3+) ions.

    Science.gov (United States)

    Pisarska, Joanna; Kos, Agnieszka; Pisarski, Wojciech A

    2014-08-14

    Lead borate glasses doubly doped with Dy(3)(+)-Tb(3+) and Tb(3+)-Eu(3+) were investigated using optical spectroscopy. Luminescence spectra of rare earths were detected under various excitation wavelengths. The main green emission band due to (5)D4→(7)F5 transition of Tb(3+) is observed under excitation of Dy(3+), whereas the main red emission band related to (5)D0→(7)F2 transition of Eu(3+) is successfully observed under direct excitation of Tb(3+). In both cases, the energy transfer processes from Dy(3+) to Tb(3+) and from Tb(3+) to Eu(3+) in lead borate glasses occur through a nonradiative processes with efficiencies up to 16% and 18%, respectively. The presence of energy transfer process was also confirmed by excitation spectra measurements. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Random lasing in Eu³⁺ doped borate glass-ceramic embedded with Ag nanoparticles under direct three-photon excitation.

    Science.gov (United States)

    Xu, Xuhui; Zhang, Wenfei; Jin, Limin; Qiu, Jianbei; Yu, Siu Fung

    2015-10-21

    We report the observation of random lasing from Eu(3+) doped borate glass ceramic films embedded with Ag nanoparticles through three-photon absorption at room temperature. Under 1179 nm ultrashort femtosecond pulse excitation, discrete sharp peaks with linewidth ∼0.4 nm emerge randomly from a broad emission band with peak wavelength at ∼612 nm. In addition, the number of sharp peaks increases with the increase of excitation power. We also show that the emission spectrum varies with different observation angles and the corresponding lasing threshold is dependent on the excitation area. Hence, we verify unambiguously that the Eu(3+) doped borate glass ceramic film supports random lasing action via three-photon absorption excitation. In addition, Ag nanoparticles, which act as light scatterers, allow the formation of random microcavities inside the bulk film.

  9. A study of physical and optical absorption spectra of VO{sup 2+} ions in potassium and sodium oxide borate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Srinivas, G., E-mail: srinu123g@gmail.com; Ramesh, B.; Kumar, J. Siva; Shareefuddin, Md.; Chary, M. N.; Sayanna, R. [Department of Physics, Osmania University, Hyderabad (India)

    2016-05-23

    Spectroscopic and physical properties of V{sub 2}O{sub 5} doped mixed alkali borate glasses are investigated. Borate glasses containing fixed concentrations of alkaline earth oxides (MgO and BaO) and alkali oxides (K{sub 2}O and Na{sub 2}O) were changes and are prepared by melt quenching technique. The values of r{sub i}, r{sub p}, R{sub m}, α{sub m} molar volume and Λ{sub th} increase and oxygen packing density, density and dopant ion concentration decrease with increasing of K{sub 2}O content. As a result there shall be an increase in the disorder of the glass network. The optical band gap energies, Urbach energy, boron-boron separation,refractive index, dielectric constant, electronic polarizability and reflection loss values are varies nonlinearly with the K{sub 2}O content which manifests the mixed alkali effect.

  10. The thermal stability and pyrolysis mechanism of boron-containing phenolic resins: The effect of phenyl borates on the char formation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shujuan; Wang, Yong; Bian, Cheng; Zhong, Yuhu [Department of Applied Chemistry, School of Science, Xi’an Jiaotong University, Xi’an 710049, People’ s Republic of China (China); Jing, Xinli, E-mail: rgfp-jing@mail.xjtu.edu.cn [Department of Applied Chemistry, School of Science, Xi’an Jiaotong University, Xi’an 710049, People’ s Republic of China (China); MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi’an, 710049, People’ s Republic of China (China)

    2015-03-15

    Graphical abstract: - Highlights: • The thermal stability and pyrolysis mechanism of cured BPR are investigated. • The high char yield of BPR results from the formed phenyl borates during curing. • Boron oxide is formed on the surface of carbonized product during pyrolysis. • The formed boron oxide revealed the cleavage of O–C bonds from phenyl borates. • The graphitization degree and graphite crystallites of PR are improved by introducing boron. - Abstract: Boron-containing phenolic resin (BPR) is a kind of the ablative resins with high-performance. Due to the lack of the exact knowledge concerning the pyrolysis mechanism of BPR, its development and application are greatly impeded. In the present paper, the chemical structure of the cured BPR and its structural evolution at high temperatures are investigated to clarify the reason for the high char yield of BPR. The results indicate that the high char yield of BPR is mainly attributed to the phenyl borates formed during curing, which can block parts of phenolic hydroxyl groups, and effectively inhibit their thermal decomposition reaction. Boron oxide is formed on the surface of carbonization products by the cleavage of O–C bonds from phenyl borates via pyrolysis, which avoids the release of volatile carbon dioxide and reduces the development of micro-structural defects of carbonization products. Introducing boron into PR improves the graphitization degree and graphite crystallites of carbonization products, which promotes the formation of a more ordered glassy carbon during pyrolysis. This study provides a new vision for the understanding of the high char yield of BPR, which makes it possible to develop a new ablative resin through molecular design.

  11. THE COMBINED EFFECT OF ORGANIC PHOSPHINATE BASED FLAME RETARDANT AND ZINC BORATE ON THE FIRE BEHAVIOR OF POLY(BUTYLENE TEREPHTHALATE

    Directory of Open Access Journals (Sweden)

    Mustafa Erdem ÜREYEN

    2016-12-01

    Full Text Available Neat poly(butylene terephthalate is highly combustible. It is not self-extinguishing, and after ignition it burns with dripping. To meet the fire safety requirements, it should be rendered flame retardant. The most common flame retardants for PBT are based on halogenated (most often brominated or phosphorus compounds. Although their efficiency is lower than halogen based flame retardants, expensive phosphorus based flame retardants for polyester are preferred, because of low smoke generation, nontoxicity and low corrosion properties. Zinc borate has been widely used with other flame retardants in wood products and in several polymers. In this work the fire behavior of zinc borate, phosphinic acid and zinc borate/phosphinic acid combination doped poly(butylene terephthalate was investigated. Firstly, the mean particle size of zinc borate (2ZnO.3B2O3.3.5H2O powders were reduced by attrition milling. Samples were produced by twin screw micro compounder. The fire properties of the ZnB, DPA and ZnB/DPA doped PBT were investigated and compared to each other by LOI and thermal analysis. LOI values of ZnB/PBT samples were found very low even with higher filling content. At higher loading of ZnB, the dripping of the sample strongly decreased and char residue increased. It was seen that organic diethyl phosphinic acid based additives DPA is particularly effective with PBT. It was found that the combination of DPA and ZnB can be used to increase the char residue, decrease spread of flame and the melt dripping of PBT.

  12. Importance of the counterion in optimization of a borate electrolyte system for analyses of anions in samples with complex matrices performed by capillary zone electrophoresis

    Czech Academy of Sciences Publication Activity Database

    Křivánková, Ludmila; Březková, M.; Gebauer, Petr; Boček, Petr

    2004-01-01

    Roč. 25, č. 20 (2004), s. 3406-3415 ISSN 0173-0835 R&D Projects: GA ČR GA203/02/0023; GA AV ČR IAA4031401 Institutional research plan: CEZ:AV0Z4031919 Keywords : background electrolyte * borate buffer * capillary zone electrophoresis Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.743, year: 2004

  13. Use of a new borate raw material for glaze formulation; Utilizacion de una nueva materia prima boracica para la formulacion de esmaltes

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Tena, M. P.; Moreno, A.; Bou, E.; Cook, S.; Galindo, M.

    2010-07-01

    The Rio Tinto Minerals company has developed a new borate (E-4972), which can be used in glaze formulation (patent WO 2007/148101). This new borate, synthesised by low-temperature calcination, fundamentally contributes five oxides: silicon oxide (SiO{sub 2}), aluminium oxide (Al{sub 2}O{sub 3}), boron oxide (B{sub 2}O{sub 3}), calcium oxide (CaO), and sodium oxide (Na{sub 2}O), its content in B{sub 2}O{sub 3} being between 10 and 11% by weight. It is largely amorphous, and quartz is the major crystalline phase present. The characteristics of this new borate, such as its low solubility and ability readily to form glassy phase, enable it to be used as a raw material in glaze compositions. Its suitability for glaze formulation has been the result of several years research in collaboration with the Instituto de Tecnologia Ceramica. In this paper, the feasibility has been studied of fabricating ceramic glazes by using a new synthetic borate raw material that contributes boron to the glaze composition without this needing to be done in fritted form. It has been possible to obtain fired glazes with similar technical and aesthetics characteristics to those obtained from industrial glaze compositions that contain typical frits in their compositions, thus enabling glazes to be formulated by using the new synthetic boron raw material. The results obtained show that this new raw material (E-4972) is particularly appropriate for use in producing glazes with low gloss at high temperature. (Author) 15 refs.

  14. D-Tagatose production in the presence of borate by resting Lactococcus lactis cells harboring Bifidobacterium longum L-arabinose isomerase.

    Science.gov (United States)

    Salonen, Noora; Salonen, Kalle; Leisola, Matti; Nyyssölä, Antti

    2013-04-01

    Bifidobacterium longum NRRL B-41409 L-arabinose isomerase (L-AI) was overexpressed in Lactococcus lactis using a phosphate depletion inducible expression system. The resting L. lactis cells harboring the B. longum L-AI were used for production of D-tagatose from D-galactose in the presence of borate buffer. Multivariable analysis suggested that high pH, temperature and borate concentration favoured the conversion of D-galactose to D-tagatose. Almost quantitative conversion (92 %) was achieved at 20 g L⁻¹ substrate and at 37.5 °C after 5 days. The D-tagatose production rate of 185 g L⁻¹ day ⁻¹ was obtained at 300 g L⁻¹ galactose, at 1.15 M borate, and at 41 °C during 10 days when the production medium was changed every 24 h. There was no significant loss in productivity during ten sequential 24 h batches. The initial D-tagatose production rate was 290 g L⁻¹ day⁻¹ under these conditions.

  15. Silica-Based and Borate-Based, Titania-Containing Bioactive Coatings Characterization: Critical Strain Energy Release Rate, Residual Stresses, Hardness, and Thermal Expansion

    Directory of Open Access Journals (Sweden)

    Omar Rodriguez

    2016-12-01

    Full Text Available Silica-based and borate-based glass series, with increasing amounts of TiO2 incorporated, are characterized in terms of their mechanical properties relevant to their use as metallic coating materials. It is observed that borate-based glasses exhibit CTE (Coefficient of Thermal Expansion closer to the substrate’s (Ti6Al4V CTE, translating into higher mode I critical strain energy release rates of glasses and compressive residual stresses and strains at the coating/substrate interface, outperforming the silica-based glasses counterparts. An increase in the content of TiO2 in the glasses results in an increase in the mode I critical strain energy release rate for both the bulk glass and for the coating/substrate system, proving that the addition of TiO2 to the glass structure enhances its toughness, while decreasing its bulk hardness. Borate-based glass BRT3, with 15 mol % TiO2 incorporated, exhibits superior properties overall compared to the other proposed glasses in this work, as well as 45S5 Bioglass® and Pyrex.

  16. Bioactive borate glass scaffolds: in vitro and in vivo evaluation for use as a drug delivery system in the treatment of bone infection.

    Science.gov (United States)

    Liu, Xin; Xie, Zongping; Zhang, Changqing; Pan, Haobo; Rahaman, Mohamed N; Zhang, Xin; Fu, Qiang; Huang, Wenhai

    2010-02-01

    The objective of this work was to evaluate borate bioactive glass scaffolds (with a composition in the system Na(2)O-K(2)O-MgO-CaO-B(2)O(3)-P(2)O(5)) as devices for the release of the drug Vancomycin in the treatment of bone infection. A solution of ammonium phosphate, with or without dissolved Vancomycin, was used to bond borate glass particles into the shape of pellets. The in vitro degradation of the pellets and their conversion to a hydroxyapatite-type material in a simulated body fluid (SBF) were investigated using weight loss measurements, chemical analysis, X-ray diffraction, and scanning electron microscopy. The results showed that greater than 90% of the glass in the scaffolds degraded within 1 week, to form poorly crystallized hydroxyapatite (HA). Pellets loaded with Vancomycin provided controlled release of the drug over 4 days. Vancomycin-loaded scaffolds were implanted into the right tibiae of rabbits infected with osteomyelitis. The efficacy of the treatment was assessed using microbiological examination and histology. The HA formed in the scaffolds in vivo, resulting from the conversion of the glass, served as structure to support the growth of new bone and blood vessels. The results in this work indicate that bioactive borate glass could provide a promising biodegradable and bioactive material for use as both a drug delivery system and a scaffold for bone repair.

  17. Determination of major, minor and trace elements in rock samples by laser ablation inductively coupled plasma mass spectrometry: Progress in the utilization of borate glasses as targets

    International Nuclear Information System (INIS)

    Leite, Tacito Dantas F.; Escalfoni, Rainerio; Fonseca, Teresa Cristina O. da; Miekeley, Norbert

    2011-01-01

    The present work is a continuation of a research study performed at our laboratory aiming at the multielement analysis of rock samples (basalts and shale) by inductively coupled plasma mass spectrometry in combination with laser ablation using borate glasses as analytical targets. Argon, nitrogen-argon mixtures and helium were evaluated as cell gases, the latter confirming its better performance. Different operational parameters of the laser, such as gas flow, energy, focus, scanning speed and sampling frequency were optimized. External calibration was made with standards prepared by fusion of geological reference materials (basalts 688 and BCR-2, obsidian SRM 278, and shale SGR-1) of different mass fractions in the meta-tetra borate matrix. Coefficients of determination (R 2 ) were > 0.99 for 30 elements from o total of 40 determined. Method validation was then performed using additional certified reference materials (BHVO-2, BIR-1, SCo-1) produced as borate targets in a similar way. Accuracies were better than 10% for most of the elements studied and analytical precisions, calculated from the residual standard deviations of calibration curves were, typically, between 6% and 10%. Additionally, the semiquantitative TotalQuant (registered) technique was applied, which gave, within the expected uncertainty for this calibration technique, concordant results when compared to the quantitative external calibration procedure. Both methods were then used for the analysis of marine shale samples, which are of great geological interest in petroleum prospecting.

  18. Chiral separation of synthetic vicinal diol compounds by capillary zone electrophoresis with borate buffer and beta-cyclodextrin as buffer additive.

    Science.gov (United States)

    Zhao, Yan; Yang, Xingbin; Jiang, Ru; Sun, Xiaoli; Liu, Wenmin; Zhang, Shengyong

    2006-05-01

    The investigation on capillary electrophoretic enantioseparation of six synthetic compounds containing vicinal diol groups has been undertaken to acquire the optimum conditions using native beta-cyclodextrin (beta-CD) as chiral selector and borate as a background electrolyte. The separation was carried out in an uncoated capillary (58.5 cm x 75 microm i.d., effective length 48.5 cm) and the effects of several important factors were investigated in detail. The results showed that beta-CD as a chiral selector exhibited good enantioselectivity and that the enantioseparation was greatly influenced by the structure of the diols, the borate concentration and the buffer pH. The optimum performance was obtained for the chiral vicinal diols under the conditions of 200 mM borate buffer of pH 9.8 containing 1.7% beta-CD at an applied voltage of 15 kV and a capillary temperature of 20 degrees C. Under the conditions, four diols were baseline separated with fast analysis time and the good theoretical plate numbers (above 10 x 10(4)) and favorable migration-time reproducibilities (RSDs below 3.0%) were obtained. The separation results were satisfactory.

  19. Examination of stainless steel-clad Connecticut Yankee fuel assembly S004 after storage in borated water

    International Nuclear Information System (INIS)

    Langstaff, D.C.; Bailey, W.J.; Johnson, A.B. Jr.; Landow, M.P.; Pasupathi, V.; Klingensmith, R.W.

    1982-09-01

    A Connecticut Yankee fuel assembly (S004) was tested nondestructively and destructively. It was concluded that no obvious degradation of the 304L stainless steel-clad spent fuel from assembly S004 occurred during 5 y of storage in borated water. Furthermore, no obvious degradation due to the pool environment occurred on 304 stainless steel-clad rods in assemblies H07 and G11, which were stored for shorter periods but contained operationally induced cladding defects. The seam welds in the cladding on fuel rods from assembly S004, H07, and G11 were similar in that they showed a wrought microstructure with grains noticeably smaller than those in the cladding base metal. The end cap welds showed a dendritically cored structure, typical of rapidly quenched austenitic weld metal. Some intergranular melting may have occurred in the heat-affected zone (HAZ) in the cladding adjacent to the end cap welds in rods from assemblies S004 and H07. However, the weld areas did not show evidence of corrosion-induced degradation

  20. Dosimetric properties of germanium doped calcium borate glass subjected to 6 MV and 10 MV X-ray irradiations

    Energy Technology Data Exchange (ETDEWEB)

    Tengku Kamarul Bahri, T.N.H., E-mail: tnhidayah2@gmail.com [Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru (Malaysia); Wagiran, H.; Hussin, R.; Saeed, M.A. [Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru (Malaysia); Hossain, I. [Department of Physics, College of Science and Arts, King Abdul Aziz University, 21911 Rabigh (Saudi Arabia); Ali, H. [Department of Radiotherapy and Oncology, Hospital Sultan Ismail, 81100 Johor Bahru (Malaysia)

    2014-10-01

    Highlights: •The TL properties of 29.9CaO–70B{sub 2}O{sub 3}: 0.1GeO{sub 2} glass has been investigated. •We exposed glass samples to 6 MV and 10 MV in a dose range of 0.5–4.0 Gy. •This glass has a potential material to be used for application in radiotherapy. -- Abstract: Germanium doped calcium borate glasses are investigated in term of thermoluminescence properties to seek their possibility to use as glass radiation dosimeter. The samples were exposed to 6 MV, and 10 MV photon beams in a dose range of 0.5–4.0 Gy. There is a single and broad thermoluminescence glow curve that exhibits its maximum intensity at about 300 °C. Linear dose response behavior has been found in this dose range for the both photon energies. Effective atomic number, TL sensitivity, and reproducibility have also been studied. It is found that the sensitivity of germanium doped sample at 6 MV is only 1.28% and it is superior to the sensitivity at 10 MV. The reproducibility of germanium doped sample is good with a percentage of relative error less than 10%. The results indicate that this glass has a potential to be used as a radiation dosimetry, especially for application in radiotherapy.

  1. Dosimetric properties of germanium doped calcium borate glass subjected to 6 MV and 10 MV X-ray irradiations

    International Nuclear Information System (INIS)

    Tengku Kamarul Bahri, T.N.H.; Wagiran, H.; Hussin, R.; Saeed, M.A.; Hossain, I.; Ali, H.

    2014-01-01

    Highlights: •The TL properties of 29.9CaO–70B 2 O 3 : 0.1GeO 2 glass has been investigated. •We exposed glass samples to 6 MV and 10 MV in a dose range of 0.5–4.0 Gy. •This glass has a potential material to be used for application in radiotherapy. -- Abstract: Germanium doped calcium borate glasses are investigated in term of thermoluminescence properties to seek their possibility to use as glass radiation dosimeter. The samples were exposed to 6 MV, and 10 MV photon beams in a dose range of 0.5–4.0 Gy. There is a single and broad thermoluminescence glow curve that exhibits its maximum intensity at about 300 °C. Linear dose response behavior has been found in this dose range for the both photon energies. Effective atomic number, TL sensitivity, and reproducibility have also been studied. It is found that the sensitivity of germanium doped sample at 6 MV is only 1.28% and it is superior to the sensitivity at 10 MV. The reproducibility of germanium doped sample is good with a percentage of relative error less than 10%. The results indicate that this glass has a potential to be used as a radiation dosimetry, especially for application in radiotherapy

  2. Physical, thermal, structural and optical absorption studies of vanadyl doped magnesium oxy-chloride bismo-borate glasses

    Directory of Open Access Journals (Sweden)

    M.S. Dahiya

    2015-06-01

    Full Text Available Oxy-chloride bismuth-borate glasses with composition xMgCl2·(30 − xMgO·20Bi2O3·50B2O3 containing 2 mol% doping of V2O5 (x = 12, 15, 20, 25 and 30 are prepared by melt-quenching technique. The structural, thermal and optical behaviors are explained by analyzing the data obtained from density (D, molar volume (Vm, theoretical optical basicity (Λth, differential scanning calorimetry (DSC, FTIR and UV–vis results. A decrease in D and increase in Vm (except for sample MBV3 for which D is maximum on increasing chloride content suggests the formation of non-bridging oxygen atoms. Maximum glass transition temperature (Tg and crystallization temperature (Tx have been observed for sample MBV3. The glass stability (S and stability ratio (S/Tg have been calculated from the values of Tg and Tx and both are having maximum values for sample MBV3. Study of the FTIR spectra in the mid-IR range reveals the presence of both triangular and tetrahedral coordinated boron. The optical studies through UV–vis spectral analysis show non-sharp edge. The optical band gap (Eg is also maximum for sample MBV3.

  3. Spectroscopic investigations on Pr³+ and Nd³+ doped strontium-lithium-bismuth borate glasses.

    Science.gov (United States)

    Rajesh, D; Balakrishna, A; Seshadri, M; Ratnakaram, Y C

    2012-11-01

    Spectroscopic investigations on different concentrations (0.1, 0.5, 1.0, 1.5 and 2.0mol%) of Pr(3+) and Nd(3+) doped strontium lithium bismuth borate glasses have been done. X-ray diffraction, SEM with EDS, absorption and luminescence spectra were recorded for all the glass matrices and analyzed. X-ray diffraction profiles and SEM images conformed amorphous nature of investigated glass samples. EDS spectra of host glass and Pr(3+)doped glass matrices gave information about the chemical composition of glass samples. From the absorption spectra of Pr(3+) and Nd(3+) ions, Judd-Ofelt (J-O) intensity parameters (Ω(λ),λ=2, 4 and 6) have been calculated and compared with other glass matrices. The emission characteristics such as radiative lifetimes (τ(R)), measured and calculated branching ratios (β) and stimulated emission cross-sections (σ(P)) have been obtained for the observed emission transitions of Pr(3+) and Nd(3+) ions in the above glass matrix for all the concentrations. From the emission spectra of Pr(3+) and Nd(3+) doped glass matrices, the effect of concentration on the quenching of intensity of (1)D(2)→(3)H(4) transition of Pr(3+) ion and (4)F(3/2)→(4)I(9/2), (4)I(11/2) and (4)I(13/2) transitions of Nd(3+) have been studied and discussed. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. STUDY OF OPTICAL AND LUMINESCENT PROPERTIES OF POTASSIUM-ALUMINA-BORATE GLASS DOPED WITH Cr3+ IONS

    Directory of Open Access Journals (Sweden)

    A. D. Gorbachev

    2016-01-01

    Full Text Available Potassium-alumina-borate glass doped with chromium ions have been synthesized and investigated, and results are presented. We have synthesized glass of 25K2O-25Al2O3-50B2O3 speciation with addition of 0.2 weight per cent of Cr. It was found out, that heat treatment induces changes in absorption and photoluminescence spectra. According to x-ray diffraction measurements, it has been shown that Al4B2O9 nanocrystalls have been obtained. The average diameter of nanocrystalls is 15 nm. Luminescence spectra have shown that Cr3+ ions are in an octahedral crystalline surrounding of the alumina ions similar to the spectrum of ruby crystal. A conclusion has been done that nanocrystalls of Al4B2O9: Cr3+ are obtained, most probably, in the researched glass. Synthesized material can be used as the base for fiber amplifier in data-transmission systems and as an active substance for medical lasers.

  5. High Borate Networks as a Platform to Modulate Temporal Release of Therapeutic Metal Ions Gallium and Strontium

    Directory of Open Access Journals (Sweden)

    O’Connell Kathleen

    2017-04-01

    Full Text Available The effect of increasing substitutions of Ga2O3:Na2O on the structure and contingent properties, of six quaternary high borate glasses was evaluated. Component ion release and particularly gallium ion release was studied post extraction, under simulated physiological conditions. Increasing substitutions of Ga2O3:Na2O (i.e. 0:1 - 6:4 resulted in destabilization of the glass network, observed by increases in component ion release and half-life of release. However, at ≥ 6:4 Ga2O3:Na2O ratio, network stabilization appeared to occur, resulting in a decrease in ion release half-life and total ion release for B, Sr, and Ga at 720 h of extraction. A linear release profile for strontium was provided by each glass composition, and for gallium by composition GB202 (70B2O3-20SrO-6Na2O-4Ga2O3 and GB203 (70B2O3-20SrO-4Na2O-6Ga2O3 for up to 720 h. 11B MAS NMR reveals that the replacement of Na2O with Ga2O3 (in the studied composition range causesa linear increase of three-fold coordinated B[3] groups at the expense of B[4] groups. The data indicates the potential formation of GaO4-tetrahedra, associated with network stabilization.

  6. Bioactive borate glass promotes the repair of radius segmental bone defects by enhancing the osteogenic differentiation of BMSCs.

    Science.gov (United States)

    Zhang, Jieyuan; Guan, Junjie; Zhang, Changqing; Wang, Hui; Huang, Wenhai; Guo, Shangchun; Niu, Xin; Xie, Zongping; Wang, Yang

    2015-11-20

    Bioactive borate glass (BG) has emerged as a promising alternative for bone regeneration due to its high osteoinductivity, osteoconductivity, compressive strength, and biocompatibility. However, the role of BG in large segmental bone repair is unclear and little is known about the underlying mechanism of BG's osteoinductivity. In this study, we demonstrated that BG possessed pro-osteogenic effects in an experimental model of critical-sized radius defects. Transplanting BG to radius defects resulted in better repair of bone defects as compared to widely used β-TCP. Histological and morphological analysis indicated that BG significantly enhanced new bone formation. Furthermore, the degradation rate of the BG was faster than that of β-TCP, which matched the higher bone regeneration rate. In addition, ions from BG enhanced cell viability, ALP activity, and osteogenic-related genes expression. Mechanistically, the critical genes Smad1/5 and Dlx5 in the BMP pathway and p-Smad1/5 proteins were significantly elevated after BG transplantation, and these effects could be blocked by the BMP/Smad specific inhibitor. Taken together, our findings suggest that BG could repair large segmental bone defects through activating the BMP/Smad pathway and osteogenic differentiation in BMSCs.

  7. In vitro bioactivity of soda lime borate glasses with substituted SrO in sodium phosphate solution

    Directory of Open Access Journals (Sweden)

    Mohamed A. Marzouk

    2014-09-01

    Full Text Available Borate glasses with the basic composition 0.6B2O3·0.2Na2O·0.2CaO and SrO progressively substituting CaO were prepared and characterized for their bone-bonding ability. The obtained glasses were thermally treated and converted to their glass-ceramic derivatives. In this study, FTIR spectral analyses were done for the prepared glasses and glass-ceramics before and after immersion in a sodium phosphate solution for extended times. The appearance of two IR bands within the spectral range 550–680 cm-1 after immersion confirms the formation of hydroxyapatite. X-ray diffraction studies and scanning electron microscope analysis supported the obtained infrared spectroscopy results. The solubility test (measurements of the weight loss in aqueous sodium phosphate solution was conducted for measuring the dissolution of both glassy and crystalline derivatives to find out the role of SrO. The corrosion behaviour of the glasses and glass-ceramics indicate the increase of weight loss with the increase of SrO content. Different suggested proposals were introduced to explain this abnormal behaviour.

  8. Effect of Bi2O3 on spectroscopic and structural properties of Er3+ doped cadmium bismuth borate glasses.

    Science.gov (United States)

    Sanghi, S; Pal, I; Agarwal, A; Aggarwal, M P

    2011-12-01

    Glasses with composition 20CdO·xBi(2)O(3)·(79.5-x)B(2)O(3) (15≤x≤35, x in mol%) containing 0.5 mol% of Er(3+) ions were prepared by melt-quench technique (1150°C in air). The amorphous nature of the glasses was confirmed by X-ray diffraction. The spectroscopic properties of the glasses were investigated using optical absorption spectra and fluorescence spectra. The phenomenological Judd-Ofelt intensity parameters Ω(λ) (λ=2, 4, 6) were determined from the spectral intensities of absorption bands in order to calculate the radiative transition probability (A(R)), radiative life time (τ(R)), branching ratios (β(R)) for various excited luminescent states. Using the near infrared emission spectra, full width at half maxima (FWHM), stimulated emission cross-section (σ(e)) and figure of merit (FOM) were evaluated and compared with other hosts. Especially, the numerical values of these parameters indicate that the emission transition (4)I(13/2)→(4)I(15/2) at 1.506 μm in Er(3+)-doped cadmium bismuth borate glasses may be useful in optical communication. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. [Effect of amount of silane coupling agent on flexural strength of dental composite resins reinforced with aluminium borate whisker].

    Science.gov (United States)

    Zhu, Ming-yi; Zhang, Xiu-yin

    2015-06-01

    To evaluate the effect of amount of silane coupling agent on flexural strength of dental composite resins reinforced with aluminium borate whisker (ABW). ABW was surface-treated with 0%, 1%, 2%, 3% and 4% silan coupling agent (γ-MPS), and mixed with resin matrix to synthesize 5 groups of composite resins. After heat-cured at 120 degrees centigrade for 1 h, specimens were tested in three-point flexure to measure strength according to ISO-4049. One specimen was selected randomly from each group and observed under scanning electron microscope (SEM). The data was analyzed with SAS 9.2 software package. The flexural strength (117.93±11.9 Mpa) of the group treated with 2% silane coupling agent was the highest, and significantly different from that of the other 4 groups (α=0.01). The amount of silane coupling agent has impact on the flexural strength of dental composite resins reinforced with whiskers; The flexual strength will be reduced whenever the amount is higher or lower than the threshold. Supported by Research Fund of Science and Technology Committee of Shanghai Municipality (08DZ2271100).

  10. Evidence of organic luminescent centers in sol-gel-synthesized yttrium aluminum borate matrix leading to bright visible emission

    Energy Technology Data Exchange (ETDEWEB)

    Burner, Pauline; Salauen, Mathieu; Ibanez, Alain; Gautier-Luneau, Isabelle [Univ. Grenoble Alpes, Inst NEEL, Grenoble (France); CNRS, Inst NEEL, Grenoble (France); Sontakke, Atul D.; Viana, Bruno [PSL Research University, Chimie ParisTech - CNRS, Institut de Recherche de Chimie Paris (France); Bardet, Michel [Universite Grenoble Alpes, CEA, CNRS, INAC, MEM, Grenoble (France); Mouesca, Jean-Marie; Gambarelli, Serge; Maurel, Vincent [Universite Grenoble Alpes, CEA, CNRS, INAC, SyMMES, Grenoble (France); Barra, Anne-Laure [Laboratoire National des Champs Magnetiques Intenses, UPR CNRS 3228, Universite Grenoble Alpes, Grenoble (France); Ferrier, Alban [PSL Research University, Chimie ParisTech - CNRS, Institut de Recherche de Chimie Paris (France); Sorbonne Universites UPMC Universites Paris 06, Paris (France)

    2017-11-06

    Yttrium aluminum borate (YAB) powders prepared by sol-gel process have been investigated to understand their photoluminescence (PL) mechanism. The amorphous YAB powders exhibit bright visible PL from blue emission for powders calcined at 450 C to broad white PL for higher calcination temperature. Thanks to {sup 13}C labelling, NMR and EPR studies show that propionic acid initially used to solubilize the yttrium nitrate is decomposed into aromatic molecules confined within the inorganic matrix. DTA-TG-MS analyses show around 2 wt % of carbogenic species. The PL broadening corresponds to the apparition of a new band at 550 nm, associated with the formation of aromatic species. Furthermore, pulsed ENDOR spectroscopy combined with DFT calculations enables us to ascribe EPR spectra to free radicals derived from small (2 to 3 rings) polycyclic aromatic hydrocarbons (PAH). PAH molecules are thus at the origin of the PL as corroborated by slow afterglow decay and thermoluminescence experiments. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Structural studies of some phospho-borate glasses using ultrasonic pulse-echo technique, DSC and IR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gaafar, M.S., E-mail: mohamed_s_gaafar@hotmail.co [Ultrasonic Laboratory, National Institute for Standards, Tersa Street, P.O. Box 136, El-Haram, El-Giza 12211 (Egypt); Afifi, H.A. [Ultrasonic Laboratory, National Institute for Standards, Tersa Street, P.O. Box 136, El-Haram, El-Giza 12211 (Egypt); Mekawy, M.M. [Thermometry Laboratory, National Institute for Standards, Tersa Street, P.O. Box 136, El-Haram, El-Giza 12211 (Egypt)

    2009-06-01

    Glasses in the system (95-x) [0.25 Na{sub 2}O-0.75 B{sub 2}O{sub 3}]-x P{sub 2}O{sub 5}-5 Fe{sub 2}O{sub 3} (0<=x<=15 mol%), have been prepared by the melt quenching technique. Elastic properties and FT-IR spectroscopic studies have been employed to study the role of P{sub 2}O{sub 5} on the structure of the glass system. Elastic properties Poisson's ratio, micro-hardness and Debye temperature have been investigated using sound wave velocity measurements at 4 MHz (both longitudinal and shear) at room temperature. The results showed that the density and the molar volume increase as both sound velocities and the determined glass transition temperatures decrease with increasing the contents of P{sub 2}O{sub 5}. Infrared spectra of the glasses reveal that the borate network consists of diborate units and is affected by the increase in the concentration of P{sub 2}O{sub 5} content as a second network former. These results are interpreted in terms of the replacement of the diborate units with B-O-B bridges by phosphate units with non-bridging oxygens (NBOs). Therefore, the elastic moduli are observed to decrease with the increase in P{sub 2}O{sub 5} content.

  12. Controlled preparation of aluminum borate powders for the development of defect-related phosphors for warm white LED lighting

    Science.gov (United States)

    Guimarães, Vinicius F.; Salaün, Mathieu; Burner, Pauline; Maia, Lauro J. Q.; Ferrier, Alban; Viana, Bruno; Gautier-Luneau, Isabelle; Ibanez, Alain

    2017-03-01

    The optimization of the elaboration conditions of a new family of highly emissive white phosphors based on glassy yttrium aluminum borates (g-YAB) compositions is presented. Their preparation from solutions is based on the polymeric precursor method (modified Pechini process), involving non-toxic and low cost precursors. The resulting resins were first dried at moderate temperatures followed by two-step annealing treatments of the obtain powders under controlled atmospheres: a first pyrolysis under nitrogen followed by a calcination under oxygen. This favored the gradual oxidation of organic moieties coming from starting materials, avoiding uncontrolled self-combustion reactions, which generate localized hot spots. This prevented phase segregations and the formation of pyrolytic carbon or carbonates, which are strongly detrimental to the luminescence properties. Thus, coupled chemical analyses and luminescence characterizations showed the high chemical homogeneity of the resulting powders and their intense emissions in the whole visible range. These emissions can be tuned from blue to warm white by adjusting the calcination temperature that is an important advantage for the development of LED devices. We showed that impurities of monovalent and divalent cations act as quenching emission centers for these phosphors. Therefore, by increasing the purity grade, we significantly enhanced the PL emissions leading to high internal quantum yields (80-90%). Finally, cathodoluminescence emissions showed the homogeneous dispersion of emitting centers in the g-YAB matrix.

  13. Synthesis and characterization of poly (dihydroxybiphenyl borate) with high char yield for high-performance thermosetting resins

    Science.gov (United States)

    Wang, Shujuan; Xing, Xiaolong; Li, Jian; Jing, Xinli

    2018-01-01

    The objective of the current work is to synthesize novel boron-containing polymers with excellent thermal resistance, and reveal the structure and the reason for the high char yield. Thus, poly (dihydroxybiphenyl borate) (PDDB) with a more rigid molecular chain, was successfully synthesized using 4,4‧-dihydroxybiphenyl and boric acid. Structural characterizations of the prepared PDDB were performed via NMR, FTIR, XPS, and XRD analyses. The results reveal that PDDB consists of aromatic, Phsbnd Osbnd B and Bsbnd Osbnd B structures as well as a small number of boron hydroxyl and phenolic hydroxyl groups. PDDB shows good solubility in strong polar solvents, which is of great importance for the modification of thermosetting resins. TGA combined with DSC were employed to evaluate the thermal properties of PDDB, and increases in the glass transition temperature (Tg) and char yield were observed with increased boron content. Tg and char yield of PDDB (800 °C, nitrogen atmosphere) reached up to 219 °C and 66.5%, respectively. PDDB was extensively characterized during pyrolysis to reveal the high char yield of PDDB. As briefly discussed, the boron oxide and boron carbide that formed during pyrolysis play a crucial role in the high char yield of PDDB, which reduces the release of volatile carbon dioxide and carbon. This research suggests that PDDB has great potential as a novel modified agent for the improvement of the comprehensive performance of thermosetting resins to broaden their applicability in the field of advanced composites.

  14. Graphene-Borate as an Efficient Fire Retardant for Cellulosic Materials with Multiple and Synergetic Modes of Action.

    Science.gov (United States)

    Nine, Md J; Tran, Diana N H; Tung, Tran Thanh; Kabiri, Shervin; Losic, Dusan

    2017-03-22

    To address high fire risks of flamable cellulosic materials, that can trigger easy combustion, flame propagation, and release of toxic gases, we report a new fire-retardant approach using synergetic actions combining unique properties of reduced graphene oxide (rGO) and hydrated-sodium metaborates (SMB). The single-step treatment of cellulosic materials by a composite suspension of rGO/SMB was developed to create a barrier layer on sawdust surface providing highly effective fire retardant protection with multiple modes of action. These performances are designed considering synergy between properties of hydrated-SMB crystals working as chemical heat-sink to slow down the thermal degradation of the cellulosic particles and gas impermeable rGO layers that prevents access of oxygen and the release of toxic volatiles. The rGO outer layer also creates a thermal and physical barrier by donating carbon between the flame and unburnt wood particles. The fire-retardant performance of developed graphene-borate composite and mechanism of fire protection are demonstrated by testing of different forms of cellulosic materials such as pine sawdust, particle-board, and fiber-based structures. Results revealed their outstanding self-extinguishing behavior with significant resistance to release of toxic and flammable volatiles suggesting rGO/SMB to be suitable alternative to the conventional toxic halogenated flame-retardant materials.

  15. Triphenyl borate as a bi-functional additive to improve surface stability of Ni-rich cathode material

    Science.gov (United States)

    Yim, Taeeun; Jang, Seol Heui; Han, Young-Kyu

    2017-12-01

    Nickel-rich cathode material has received marked attention as an advanced cathode material, however, its inferior surface property limits the achievement of high performance in lithium-ion batteries. We propose the use of a bi-functional additive of triphenyl borate (TPB) for improvement of the safety and electrochemical performance of Ni-rich cathode materials. First, TPB removes residual lithium species from the Ni-rich cathode surface via chemical binding with anion part of residual lithium species, and effectively reduces swelling behavior of the cell. Second, TPB creates effective cathode-electrolyte interphase (CEI) layers on the electrode surface by an electrochemical reaction, and greatly enhances the surface stability of the nickel-rich cathode. This work demonstrate that a cell cycled with the TPB additive exhibits a remarkable retention of 88.6% at 60 °C after 100 cycles for an NCM721 cathode material. We suggest a working mechanism for TPB based on systematic analyses, including in-situ and ex-situ experiments.

  16. Role of SrO on the bioactivity behavior of some ternary borate glasses and their glass ceramic derivatives.

    Science.gov (United States)

    Abdelghany, A M; Ouis, M A; Azooz, M A; ElBatal, H A; El-Bassyouni, G T

    2016-01-05

    Borate glasses containing SrO substituting both CaO and NaO were prepared and characterized for their bioactivity or bone bonding ability. Glass ceramic derivatives were prepared by thermal heat treatment process. FTIR, XRD and SEM measurements for the prepared glass and glass-ceramics before and after immersion in sodium phosphate solution for one and two weeks were carried out. The appearance of two IR peaks within the range 550-680cm(-1) after immersion in phosphate solution indicates the formation of hydroxyapatite or equivalent Sr phosphate layer. X-ray diffraction data agree with the FTIR spectral analysis. The solubility test was carried out for both glasses and glass ceramics derivatives in the same phosphate solution. The introduction of SrO increases the solubility for both glasses and glass ceramics and this is assumed to be due to the formation of Sr phosphate which is more soluble than calcium phosphate (hydroxyapatite). SEM images reveal varying changes in the surfaces of glass ceramics after immersion according to the SrO content. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. In vitro bioactivity behavior of modified multicomponent borate glasses containing dopants of Ag2O, CuO, CeO2 or V2O5

    Science.gov (United States)

    Marzouk, M. A.; ElBatal, F. H.; Ghoneim, N. A.

    2018-02-01

    Some multi-component borate glasses containing dopants of Ag2O, CuO, CeO2 or V2O5 were prepared. Multi-characterization techniques were carried out to investigate their bioactivity, corrosion weight loss after immersion in phosphate solution. Controlled thermal heat-treatment by two-step technique was done to convert the prepared glasses to their corresponding glass-ceramic derivatives. X-ray diffraction analysis was performed to identify the crystalline phases formed by thermal treatment. Infrared absorption of glasses and glass-ceramics reveal vibrational bands due to combined main triangular and tetrahedral borate groups in their specific wavenumbers besides some sharing of phosphate group. After immersion in the phosphate solution, two extra characteristic peaks are generated indicating the bioactivity of the studied glasses and glass-ceramics through the formation of calcium phosphate (hydroxyapatite). X-ray diffraction data indicate the formation of crystalline phases which are variable with the introduced dopants. The main crystalline phase identified is calcium borate together with some other phases some of which contain phosphate ions. These data indicate that the presence of CaO and P2O5 initiates phase separation and subsequent crystallization of the parent and doped glasses. Weight loss data indicate that glass-ceramics are obviously durable than the parent glasses. SEM micrographs of glass-ceramics before immersion show multiconstituent crystalline phases due to the basic chemical composition consisting of multicomponent mixed alkali and alkaline earth oxides beside P2O5 and with the main B2O3 constituent. After immersion, the crystalline phases are identified to be more distinct in different shapes because of the multi-composition involved.

  18. Secondary neutron dose measurement for proton eye treatment using an eye snout with a borated neutron absorber

    Science.gov (United States)

    2013-01-01

    Background We measured and assessed ways to reduce the secondary neutron dose from a system for proton eye treatment. Methods Proton beams of 60.30 MeV were delivered through an eye-treatment snout in passive scattering mode. Allyl diglycol carbonate (CR-39) etch detectors were used to measure the neutron dose in the external field at 0.00, 1.64, and 6.00 cm depths in a water phantom. Secondary neutron doses were measured and compared between those with and without a high-hydrogen–boron-containing block. In addition, the neutron energy and vertices distribution were obtained by using a Geant4 Monte Carlo simulation. Results The ratio of the maximum neutron dose equivalent to the proton absorbed dose (H(10)/D) at 2.00 cm from the beam field edge was 8.79 ± 1.28 mSv/Gy. The ratio of the neutron dose equivalent to the proton absorbed dose with and without a high hydrogen-boron containing block was 0.63 ± 0.06 to 1.15 ± 0.13 mSv/Gy at 2.00 cm from the edge of the field at depths of 0.00, 1.64, and 6.00 cm. Conclusions We found that the out-of-field secondary neutron dose in proton eye treatment with an eye snout is relatively small, and it can be further reduced by installing a borated neutron absorbing material. PMID:23866307

  19. The effect of the cation alkyl chain length on density and diffusion in dialkylpyrrolidinium bis(mandelato)borate ionic liquids.

    Science.gov (United States)

    Filippov, Andrei; Taher, Mamoun; Shah, Faiz Ullah; Glavatskih, Sergei; Antzutkin, Oleg N

    2014-12-28

    The physicochemical properties of ionic liquids are strongly affected by the selective combination of the cations and anions comprising the ionic liquid. In particular, the length of the alkyl chains of ions has a clear influence on the ionic liquid's performance. In this paper, we study the self-diffusion of ions in a series of halogen-free boron-based ionic liquids (hf-BILs) containing bis(mandelato)borate anions and dialkylpyrrolidinium cations with long alkyl chains CnH2n+1 with n from 4 to 14 within a temperature range of 293-373 K. It was found that the hf-BILs with n = 4-7 have very similar diffusion coefficients, while hf-BILs with n = 10-14 exhibit two liquid sub-phases in almost the entire temperature range studied (293-353 K). Both liquid sub-phases differ in their diffusion coefficients, while values of the slower diffusion coefficients are close to those of hf-BILs with shorter alkyl chains. To explain the particular dependence of diffusion on the alkyl chain length, we examined the densities of the hf-BILs studied here. It was shown that the dependence of the density on the number of CH2 groups in long alkyl chains of cations can be accurately described using a "mosaic type" model, where regions of long alkyl chains of cations (named 'aliphatic' regions) and the residual chemical moieties in both cations and anions (named 'ionic' regions) give additive contributions. Changes in density due to an increase in temperature and the number of CH2 groups in the long alkyl chains of cations are determined predominantly by changes in the free volume of the 'ionic' regions, while 'aliphatic' regions are already highly compressed by van der Waals forces, which results in only infinitesimal changes in their free volumes with temperature.

  20. Spectroscopic investigations of Nd3+ doped Lithium Lead Alumino Borate glasses for 1.06 μm laser applications

    Science.gov (United States)

    Deopa, Nisha; Rao, A. S.; Gupta, Mohini; Vijaya Prakash, G.

    2018-01-01

    Neodymium doped lithium lead alumino borate glasses were synthesized with the molar composition 10Li2Osbnd 10PbOsbnd (10-x) Al2O3sbnd 70B2O3sbnd x Nd2O3 (where, x = 0.1, 0.5, 1.0, 1.5, 2.0 and 2.5 mol %) via conventional melt quenching technique to understand their lasing potentialities using the absorption, emission and photoluminescence decay spectral measurements. The oscillator strengths measured from the absorption spectra were used to estimate the Judd-Ofelt intensity parameters using least square fitting procedure. The emission spectra recorded for the as-prepared glasses under investigation exhibit two emission transitions 4F3/2 → 4I11/2 (1063 nm) and 4F3/2 → 4I9/2 (1350 nm) for which radiative parameters have been evaluated. The emission intensity increases with increase in Nd3+ ion concentration up to 1 mol % and beyond concentration quenching took place. The decay profile shows single exponential nature for lower Nd3+ ion concentration and non-exponential for higher concentration. To elucidate the nature of energy transfer process, the non-exponential decay curves were well fitted to Inokuti-Hirayama model. The relatively higher values of emission cross-sections, branching ratios and quantum efficiency values obtained for 1.0 mol% of Nd3+ ions in LiPbAlB glass suggests it's aptness in generating lasing action at 1063 nm in NIR region.

  1. Effect of pyrophosphate ions on the conversion of calcium–lithium–borate glass to hydroxyapatite in aqueous phosphate solution

    Science.gov (United States)

    Fu, Hailuo; Day, Delbert E.; Huang, Wenhai

    2010-01-01

    The conversion of glass to a hydroxyapatite (HA) material in an aqueous phosphate solution is used as an indication of the bioactive potential of the glass, as well as a low temperature route for preparing biologically useful materials. In this work, the effect of varying concentrations of pyrophosphate ions in the phosphate solution on the conversion of a calcium–lithium–borate glass to HA was investigated. Particles of the glass (150–355 µm) were immersed for up to 28 days in 0.25 M K2HPO4 solution containing 0–0.1 M K4P2O7. The kinetics of degradation of the glass particles and their conversion to HA were monitored by measuring the weight loss of the particles and the ionic concentration of the solution. The structure and composition of the conversion products were analyzed using X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy. For K4P2O7 concentrations of up to 0.01 M, the glass particles converted to HA, but the time for complete conversion increased from 2 days (no K4P2O7) to 10 days (0.01 M K4P2O7). When the K4P2O7 concentration was increased to 0.1 M, the product consisted of an amorphous calcium phosphate material, which eventually crystallized to a pyrophosphate product (predominantly K2CaP2O7 and Ca2P2O7). The consequences of the results for the formation of HA materials and devices by the glass conversion route are discussed. PMID:20680413

  2. Novel borate glass/chitosan composite as a delivery vehicle for teicoplanin in the treatment of chronic osteomyelitis.

    Science.gov (United States)

    Jia, Wei-Tao; Zhang, Xin; Luo, Shi-Hua; Liu, Xin; Huang, Wen-Hai; Rahaman, Mohamed N; Day, Delbert E; Zhang, Chang-Qing; Xie, Zong-Ping; Wang, Jian-Qiang

    2010-03-01

    Composite materials composed of borate bioactive glass and chitosan (designated BGC) were investigated in vitro and in vivo as a new delivery system for teicoplanin in the treatment of chronic osteomyelitis induced by methicillin-resistant Staphylococcus aureus (MRSA). In vitro, the release of teicoplanin from BGC pellets into phosphate-buffered saline (PBS), as well as its antibacterial activity, were determined. The compressive strength of the pellets was measured after specific immersion times, and the structure of the pellets was characterized using scanning electron microscopy and X-ray diffraction. In vivo, the tibial cavity of New Zealand White rabbits was injected with MRSA strain to induce chronic osteomyelitis, treated by debridement after 4weeks, implanted with teicoplanin-loaded BGC pellets (designated TBGC) or BGC pellets, or injected intravenously with teicoplanin. After 12weeks' implantation, the efficacy of the TBGC pellets for treating osteomyelitis was evaluated using hematological, radiological, microbiological and histological techniques. When immersed in PBS, the TBGC pellets provided a sustained release of teicoplanin, while the surface of the pellets was converted to hydroxyapatite (HA). In vivo, the best therapeutic effect was observed in animals implanted with TBGC pellets, resulting in significantly lower radiological and histological scores, a lower positive rate of MRSA culture, and an excellent bone defect repair, without local or systemic side effects. The results indicate that TBGC pellets are effective in treating chronic osteomyelitis by providing a sustained release of teicoplanin, in addition to participating in bone regeneration. Copyright 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  3. Spectroscopic studies of Sm3+ ions activated lithium lead alumino borate glasses for visible luminescent device applications

    Science.gov (United States)

    Deopa, Nisha; Rao, A. S.

    2017-10-01

    Photoluminescence (PL) characterization of Lithium Lead Alumino Borate (LiPbAlB) glasses doped with Sm3+ ions at varying concentrations have been studied by using absorption, excitation, emission, time resolved and confocal image measurements. From the absorption spectra, Judd-Ofelt (J-O) intensity parameters were evaluated and in turn used to estimate various radiative parameters for the fluorescent levels of Sm3+ ion doped LiPbAlB glasses. The PL spectra of Sm3+ ions exhibit three emission bands corresponding to the transitions 4G5/2 → 6H5/2, 6H7/2 and 6H9/2, for which the emission cross-sections and branching ratios were evaluated to know the potentialities of these materials as visible luminescent devices. The decay spectral profiles measured for 4G5/2 → 6H7/2 transition level were used to estimate quantum efficiency of the as-prepared glasses. The non-exponential decay curves observed for higher Sm3+ ion concentrations were well fitted to Inokuti-Hirayama model to understand the predominant energy transfer mechanism involved in the as-prepared glasses. CIE chromaticity coordinates and correlated color temperatures (CCT) were evaluated to understand the utility of the titled glasses in cool white light generation. The confocal images captured under 405 nm CW laser excitation show intense reddish-orange color. From the evaluated radiative parameters, emission cross-sections, quantum efficiency, CIE co-ordinates, CCT temperatures and confocal images, it was observed that LiPbAlB glass with 0.5 mol% Sm3+ ions are more suitable for w-LEDs and reddish-orange luminescent device applications.

  4. The effect of Li2O and LiF on structural properties of cobalt doped borate glasses

    Directory of Open Access Journals (Sweden)

    A.M. Abdelghany

    2017-10-01

    Full Text Available Two glassy (LiF–B2O3 and (Li2O–B2O3 systems containing different content of CoO dopants (0.05, 0.1, 0.15, 0.2 wt% were prepared. UV/Vis optical absorption of base glasses reveals a strong UV absorption bands attributed to unavoidable contaminated trace iron impurities. CoO-doped glasses show extra three visible bands due to both octahedral and tetrahedral Co2+ ions related to the little variation between energies of ligand field stabilization between the two coordination states. Fluoride containing glasses show limited variations in the spectral properties due to the different ligand strength of the anions (F− and O2−. FTIR spectra display characteristic modes of vibrations due to triangular and tetrahedral borate groups. It is assumed that LiF acts as Li2O in promoting the formation of tetrahedral (BO3F units which possess the same wavenumber position for vibrations of (BO4 units in the range of 800–1200 cm−1. CoO causes no distinct variations in number or position of characteristic IR vibrational bands due to their low dopant level (0.05–0.2%. A new suggested trial has been utilized to calculate the percent of four coordinated borons from both optical and FTIR spectra to give more insight on the role of CoO as dopant on these spectral properties and on the calculated parameters.

  5. Effect of pyrophosphate ions on the conversion of calcium-lithium-borate glass to hydroxyapatite in aqueous phosphate solution.

    Science.gov (United States)

    Fu, Hailuo; Rahaman, Mohamed N; Day, Delbert E; Huang, Wenhai

    2010-10-01

    The conversion of glass to a hydroxyapatite (HA) material in an aqueous phosphate solution is used as an indication of the bioactive potential of the glass, as well as a low temperature route for preparing biologically useful materials. In this work, the effect of varying concentrations of pyrophosphate ions in the phosphate solution on the conversion of a calcium-lithium-borate glass to HA was investigated. Particles of the glass (150-355 μm) were immersed for up to 28 days in 0.25 M K(2)HPO(4) solution containing 0-0.1 M K(4)P(2)O(7). The kinetics of degradation of the glass particles and their conversion to HA were monitored by measuring the weight loss of the particles and the ionic concentration of the solution. The structure and composition of the conversion products were analyzed using X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy. For K(4)P(2)O(7) concentrations of up to 0.01 M, the glass particles converted to HA, but the time for complete conversion increased from 2 days (no K(4)P(2)O(7)) to 10 days (0.01 M K(4)P(2)O(7)). When the K(4)P(2)O(7) concentration was increased to 0.1 M, the product consisted of an amorphous calcium phosphate material, which eventually crystallized to a pyrophosphate product (predominantly K(2)CaP(2)O(7) and Ca(2)P(2)O(7)). The consequences of the results for the formation of HA materials and devices by the glass conversion route are discussed.

  6. NIR fluorescence spectroscopic investigations of Er{sup 3+}-ions doped borate based tellurium calcium zinc niobium oxide glasses

    Energy Technology Data Exchange (ETDEWEB)

    Ravi, O. [Department of Instrumentation, Sri Venkateswara University, Tirupati 517502 (India); Dhoble, S.J. [Department of Physics, RTM Nagpur University, Nagpur 440033 (India); Ramesh, B.; Devarajulu, G. [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India); Reddy, C. Madhukar [Department of Physics, AP Model School, Yerravaripalem 517194 (India); Linganna, K. [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India); Reddy, G. Rajasekhar [Department of Instrumentation, Sri Venkateswara University, Tirupati 517502 (India); Raju, B. Deva Prasad, E-mail: drdevaprasadraju@gmail.com [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India); Department of Future Studies, Sri Venkateswara University, Tirupati 517502 (India)

    2015-08-15

    A series of Er{sup 3+} ions doped tellurium calcium zinc niobium borate glasses were prepared by the melt quenching technique. The prepared samples were investigated by optical absorption and near infrared fluorescence spectroscopic studies. The obtained Judd–Ofelt intensity parameters Ω{sub λ} (λ=2, 4 and 6) were determined through experimental and calculated oscillator strengths obtained from absorption spectra and their results are studied and compared with reported literature. The stark-level energies of {sup 4}I{sub 13/2} excited and {sup 4}I{sub 15/2} ground states were evaluated by using both the absorption and emission measurements. The effect of Er{sup 3+} ion concentration on the emission intensity of {sup 4}I{sub 13/2}→{sup 4}I{sub 15/2} transition was discussed. Intense and broad 1.53 µm infrared fluorescence is observed at 980 nm diode laser excitation. Photoluminescence (PL) and its decay behavior studies were carried out for the transition {sup 4}I{sub 13/2}→{sup 4}I{sub 15/2} at 1.53 µm emission. The broad emission together with higher values of the bandwidth (81 nm), stimulated emission cross-section (32.25×10{sup −22} cm{sup 2}) and lifetime (530 µs for 1.0 mol% of Er{sup 3+}) of level {sup 4}I{sub 13/2} make these glasses attractive for broadband amplifiers. From the analysis of spectroscopic data, the present glass is a prospective photonic material for practical applications in the visible and NIR region. - Highlights: • In this study we prepared TCZNB glasses doped with Er{sup 3+} ions. • Glasses are characterized with absorption, emission and lifetime analysis. • Judd–Ofelt theory is used to calculate radiative properties. • TCZNB glasses could be used as NIR lasers.

  7. Thiol-ene synthesis and characterization of lithium bis(malonato)borate single-ion conducting gel polymer electrolytes.

    Science.gov (United States)

    Weber, Ryan L; Mahanthappa, Mahesh K

    2017-10-25

    The development of high capacity anodes and high voltage cathodes for advanced lithium-ion batteries motivates the search for new polymer electrolytes that exhibit superior electrochemical stabilities and high ionic conductivities. We report a convenient, three-step synthesis of lithium bis(non-8-enyl-malonato)borate (LiBNMB) as a α,ω-diene monomer, which undergoes thermally initiated thiol-ene crosslinking polymerizations in propylene carbonate to yield gel polymer electrolytes with high lithium ion concentrations (∼0.9 M). By conducting these crosslinking polymerizations using mixtures of di- and tri-thiols and LiBNMB with [thiol] : [ene] = 1 : 1, we synthesized a series of gel networks with dynamic elastic moduli ranging from G' = 40-79 kPa that increase monotonically with trifunctional crosslinker content. While ionic conductivities for these polymer gels measured by electrochemical impedance spectroscopy at 22 °C are σ = 0.82-2.5 × 10 -6 S cm -1 , we show that the conductivity of propylene carbonate-solvated lithium ions though the bulk of these gel electrolytes is 8.5 × 10 -5 S cm -1 independent of crosslinker density. However, the conductivities of the gel interfaces depend sensitively on crosslinker content, suggesting the importance of segmental rearrangement dynamics at the electrode interface in limiting the rate of ion motion. Thus, the design of highly conductive polymer electrolytes for advanced batteries demands careful design of both the internal and interfacial properties of these new materials.

  8. A density functional theory study of the carbon-coating effects on lithium iron borate battery electrodes.

    Science.gov (United States)

    Loftager, Simon; García-Lastra, Juan María; Vegge, Tejs

    2017-01-18

    Lithium iron borate (LiFeBO 3 ) is a promising cathode material due to its high theoretical specific capacity, inexpensive components and small volume change during operation. Yet, challenges related to severe air- and moisture-induced degradation have prompted the utilization of a protective coating on the electrode which also improves the electronic conductivity. However, not much is known about the preferential geometries of the coating as well as how these coating-electrode interfaces influence the lithium diffusion between the coating and the electrode. Here, we therefore present a density functional theory (DFT) study of the anchoring configurations of carbon coating on the LiFeBO 3 electrode and its implications on the interfacial lithium diffusion. Due to large barriers associated with Li-ion diffusion through a parallel-oriented pristine graphene coating on the FeBO 3 and LiFeBO 3 electrode surfaces, large structural defects in the graphene coating are required for fast Li-ion diffusion. However, such defects are expected to exist only in small concentrations due to their high formation energies. Alternative coating geometries were therefore investigated, and the configuration in which the coating layers were anchored normal to the electrode surface at B and O atoms was found to be most stable. Nudged elastic band (NEB) calculations of the lithium diffusion barriers across the interface between the optimally oriented coating layers and the electrode show no kinetic limitations for lithium extraction and insertion. Additionally, this graphite-coating configuration showed partial blocking of electrode-degrading species.

  9. Preparation, crystal structure and thermal expansion of a novel layered borate, Ba{sub 2}Bi{sub 3}B{sub 25}O{sub 44}

    Energy Technology Data Exchange (ETDEWEB)

    Krivovichev, S.V. [Department of Crystallography, St. Petersburg State University, University Emb 7/9, 199034 St. Petersburg (Russian Federation); Bubnova, R.S.; Volkov, S.N. [Department of Crystallography, St. Petersburg State University, University Emb 7/9, 199034 St. Petersburg (Russian Federation); Grebenshchikov Institute of Silicate Chemistry, Russian Academy of Sciences, Makarov Emb 2, 199053 St. Petersburg (Russian Federation); Krzhizhanovskaya, M.G., E-mail: krzhizhanovskaya@mail.ru [Department of Crystallography, St. Petersburg State University, University Emb 7/9, 199034 St. Petersburg (Russian Federation); Egorysheva, A.V. [Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Leninsky Prospect 31, GSP-1, Moscow 119991 (Russian Federation); Filatov, S.K. [Department of Crystallography, St. Petersburg State University, University Emb 7/9, 199034 St. Petersburg (Russian Federation)

    2012-12-15

    Single crystals of a new compound, Ba{sub 2}Bi{sub 3}B{sub 25}O{sub 44}, were grown by cooling a melt of non-stoichiometric composition. The crystal structure was solved by direct methods and refined to R=0.030 (wR=0.090). The compound is trigonal, R3{sup Macron }m, a=7.851(2), c=46.20(1) A, V=2466.6(6) A{sup 3}, Z=3. The structure is based upon a borate layered anion of the type not previously observed in inorganic compounds. The layer consists of three sublayers; it is {approx}13 A thick and oriented parallel to (001). Two of the sublayers are built from triborate groups, [B{sub 3}O{sub 8}]{sup 7-}, whereas the central sublayer consists of triborate groups, [B{sub 3}O{sub 6}]{sup 3-}. The interlayer space is occupied by the Bi{sup 3+} ions in octahedral coordination. The Ba{sup 2+} cations are located in the cavities within borate layer. The single-phase polycrystalline sample of Ba{sub 2}Bi{sub 3}B{sub 25}O{sub 44} prepared by solid-state reactions from a stoichiometric mixture has been investigated by high-temperature X-ray powder diffraction in air. Anisotropic character of the thermal expansion is not typical for layered structures: {alpha}{sub a}=12, {alpha}{sub c}=6, {alpha}{sub V}=30 Multiplication-Sign 10{sup -6} Degree-Sign S{sup -1} at 25 Degree-Sign S; anisotropy increases on heating: {alpha}{sub a}=12, {alpha}{sub c}=0, {alpha}{sub V}=24 Multiplication-Sign 10{sup -6} Degree-Sign S{sup -1} at 700 Degree-Sign S. - Graphical abstract: Correlation between the pole figure of the thermal expansion coefficients and the structure of Ba{sub 2}Bi{sub 3}B{sub 25}O{sub 44} projected onto ac plane. The pole figures are presented for room temperature and 700 Degree-Sign C. Highlights: Black-Right-Pointing-Pointer A novel borate Ba{sub 2}Bi{sub 3}B{sub 25}O{sub 44} has been synthesized by cooling a non-stoichiometric melt. Black-Right-Pointing-Pointer The crystal structure is based upon a novel borate layered anion ({approx}13 A thick). Black

  10. Effect of glass composition on the relaxation of the 4Isub(13/2) level of erbium ions in borate and silicate glasses

    International Nuclear Information System (INIS)

    Ryba-Romanowski, W.; Jezowska-Trzebiatowska, B.

    1979-01-01

    The effect of glass nerwork formers and glass modifiers on radiative transition probabilities and quantum efficiencies of the 4 Isub(13/2) level of Er +3 ions in ternary borate and silicate glasses was studied by both absorption and emission spectroscopy. It was found that the transition probabilities may be widely varied by changes glass network former and alkali ion substitution. The role of multiphonon emission and O-H vibration in the relaxation of the 4 Isub(13/2) level is discussed. (author)

  11. Evaluation of the proliferation and differentiation behaviors of mesenchymal stem cells with partially converted borate glass containing different amounts of strontium in vitro.

    Science.gov (United States)

    Zhu, Yi; Ouyang, Yuanming; Chang, Yi; Luo, Congfeng; Xu, Jun; Zhang, Changqing; Huang, Wenhai

    2013-04-01

    The objective of this study was to examine the proliferation and differentiation behaviors of different compositions of strontium-containing (from 0-12 mol%) borate glasses with mesenchymal stem cells (MSCs). The Cell Counting Kit-8 (CCK-8) assay revealed that after three days of culturing, the 6Sr group had the highest cell growth rate. Analysis of cell morphology revealed that cells proliferated well near the particles of the samples in all the groups on day 3. On day 7, cells in the 6Sr group demonstrated a higher proliferation rate than other 4 groups under the microscope. When performing the Live-Dead staining experiment, the 6Sr group had the least number of dead cells. Total DNA qualification indicated that the 6Sr group had a statistically higher concentration compared with the remaining groups. It was found that on day 7, compared with the 0Sr group, the core binding factor α1 (Cbfa1) mRNA expression level was significantly higher in the 6Sr, 9Sr and 12Sr groups. On day 14, compared with the 0Sr group, the bone sialoprotein (BSP) mRNA level was significantly higher in the 6Sr group. Additionally, on day 21, the 6Sr and 9Sr groups demonstrated higher osteocalcin (OCN) mRNA expression levels compared with the 0Sr group. In the alkaline phosphatase (ALP) activity test, on day 21, the 6Sr group presented a higher activity than the 0Sr group. Further, the number of mineralized nodules per unit in MSCs was measured by Alizarin Red S staining. The results showed that the 6Sr and 9Sr groups had the greatest number of mineralized nodules. Therefore, it could be concluded that borate glasses containing strontium oxide of 0, 3, 6, 9 and 12 mol% demonstrate a significant level of proliferation when interacting with MSCs. The borate glass containing 6 mol% strontium oxide had the greatest level of proliferation when cultured with MSCs. The borate glass containing 6 and 9 mol% strontium oxide facilitated an improved bone formation ability compared with the remaining

  12. The copper-catalysed Suzuki-Miyaura coupling of alkylboron reagents: disproportionation of anionic (alkyl)(alkoxy)borates to anionic dialkylborates prior to transmetalation.

    Science.gov (United States)

    Basnet, Prakash; Thapa, Surendra; Dickie, Diane A; Giri, Ramesh

    2016-09-25

    We report the first example of Cu(I)-catalysed coupling of alkylboron reagents with aryl and heteroaryl iodides that affords products in good to excellent yields. Preliminary mechanistic studies with alkylborates indicate that the anionic (alkoxy)(alkyl)borates, generated from alkyllithium and alkoxyboron reagents, undergo disproportionation to anionic dialkylborates and that both anionic alkylborates are active for transmetalation to a Cu(I)-catalyst. Results from a radical clock experiment and the Hammett plot imply that the reaction likely proceeds via a non-radical pathway.

  13. The effect of borate and phosphate inhibitors on corrosion rate material SS321 and incoloy 800 in chloride containing solution by using potentiodynamic method

    International Nuclear Information System (INIS)

    Febriyanto; Sriyono; Satmoko, Ari

    1998-01-01

    Determination of corrosion rate of steam generator materials (SS 321 and incoloy 800) in chloride containing solution using potentiodynamic method from CMS 100. NaCl 1%, 3% and 5% solution using is used as tested solution. A tested material is grounded by grinding paper on grade 400 600, 800 and 1000, then polished by METADI 1/4 microns paste to get homogeneity. Furthermore, the tested materials is mounted by epoxide resin, so only the surface which contacts to tested solution is open. From the result obtained that borate and phosphate inhibitor can reduce corrosion rate and aggressiveness of chloride ion

  14. Pyrazole cleavage of tris(3,5-dimethylpyrazolyl)borate with Ruthenium(II) complexes: Synthesis, structural characterization and DFT studies

    Science.gov (United States)

    Kharbani, Donkupar; Deb, Debojit Kumar; Mawnai, Ibaniewkor L.; Kurbah, Sunshine D.; Sarkar, Biplab; Rymmai, E. K.

    2017-04-01

    The reaction of [Ru(H)(Cl)(CO)(PPh3)3] (1) with KTp* (KTp* = Potassium tris(3,5-dimethylpyrazolyl)borate) in a refluxing toluene yields a mixture of [RuTp*(H)(CO)(PPh3)] (2), [Ru(H)(Cl)(pz*H)(CO)(PPh3)2] (3), and [H(pz*)B(μ-pz*)2B(pz*)H] (4) (pz*H = 3,5-dimethylpyrazole). The products (3) and (4) were obtained by the degradation of the scorpionate ligand, Tp*. These complexes were characterised by IR, 1H NMR, UV, X-ray crystallography and DFT calculations.

  15. Photoinduced Reactivity of the Soft Hydrotris(6-tert-butyl-3-thiopyridazinyl)borate Scorpionate Ligand in Sodium, Potassium, and Thallium Salts.

    Science.gov (United States)

    Tüchler, Michael; Belaj, Ferdinand; Raber, Georg; Neshchadin, Dmytro; Mösch-Zanetti, Nadia C

    2015-09-08

    The soft scorpionate ligand hydrotris(6-tert-butyl-3-thiopyridazinyl)borate (Tn) was found to exhibit pronounced photoreactivity. Full elucidation of this process revealed the formation of 6-tert-butylpyridazine-3-thione (PnH) and 4,5-dihydro-6-tert-butylpyridazine-3-thione (H2PnH). Under exclusion of light, no solvolytic reactions occur, allowing the development of high-yield preparation protocols for the sodium, potassium, and thallium salts and improving the yield for their derived copper boratrane complex. The photoreactivity is relevant for all future studies with electron-deficient scorpionate ligands.

  16. Transition metal complexes of oxazolinylboranes and cyclopentadienyl-bis(oxazolinyl)borates: Catalysts for asymmetric olefin hydroamination and acceptorless alcohol decarbonylation

    Energy Technology Data Exchange (ETDEWEB)

    Manna, Kuntal [Ames Lab., Ames, IA (United States)

    2012-12-17

    The research presented and discussed in this dissertation involves the synthesis of transition metal complexes of oxazolinylboranes and cyclopentadienyl-bis(oxazolinyl)borates, and their application in catalytic enantioselective olefin hydroamination and acceptorless alcohol decarbonylation. Neutral oxazolinylboranes are excellent synthetic intermediates for preparing new borate ligands and also developing organometallic complexes. Achiral and optically active bis(oxazolinyl)phenylboranes are synthesized by reaction of 2-lithio-2-oxazolide and 0.50 equiv of dichlorophenylborane. These bis(oxazolinyl)phenylboranes are oligomeric species in solid state resulting from the coordination of an oxazoline to the boron center of another borane monomer. The treatment of chiral bis(oxazolinyl)phenylboranes with sodium cyclopentadienide provide optically active cyclopentadienyl-bis(oxazolinyl)borates H[PhB(C5H5)(OxR)2] [OxR = Ox4S-iPr,Me2, Ox4R-iPr,Me2, Ox4S-tBu]. These optically active proligands react with an equivalent of M(NMe2)4 (M = Ti, Zr, Hf) to afford corresponding cyclopentadienyl-bis(oxazolinyl)borato group 4 complexes {PhB(C5H4)(OxR)2}M(NMe2)2 in high yields. These group 4 compounds catalyze cyclization of aminoalkenes at room temperature or below, providing pyrrolidine, piperidine, and azepane with enantiomeric excesses up to 99%. Our mechanistic investigations suggest a non-insertive mechanism involving concerted C-N/C-H bond formation in the turnover limiting step of the catalytic cycle. Among cyclopentadienyl-bis(oxazolinyl)borato group 4 catalysts, the zirconium complex {PhB(C5H4)(Ox4S-iPr,Me2)2}Zr(NMe2)2 ({S-2}Zr(NMe2)2) displays highest activity and enantioselectivity. Interestingly, S-2

  17. To immobilize polyethylene glycol-borate ester/lithium fluoride in graphene oxide/poly(vinyl alcohol for synthesizing new polymer electrolyte membrane of lithium-ion batteries

    Directory of Open Access Journals (Sweden)

    Y. F. Huang

    2017-01-01

    Full Text Available Polymer electrolyte membranes (PEMs are potentially applicable in lithium-ion batteries with high safety, low cost and good performance. Here, to take advantages of ionic conductivity and selectivity of borate ester-functionalized small molecules as well as structural properties of polymer nanocomposite, a strategy of immobilizing as-synthesized polyethylene glycol-borate ester/lithium fluoride (B-PEG/LiF in graphene oxide/poly(vinyl alcohol (GO/PVA to prepare a PEM is put forward. Chemical structure of the PEM is firstly characterized by 1H-, 11B- and 19F-nuclear magnetic resonance spectra, and Fourier transform infrared spectroscopy spectra, respectively, and then is further investigated under consideration of the interactions among PVA, B-PEG and LiF components. The immobilization of B-PEG/LiF in PVA-based structure is confirmed. As the interactions within electrolyte components can be further tuned by GO, ionic conductivity (~10–3 S·cm–1, lithium-ion transfer number (~0.49, and thermal (~273 °C/electrochemical (>4 V stabilities of the PEM can be obtained, and the feasibility of PEMs applied in a lithium-ion battery is also confirmed. It is believed that such PEM is a promising candidate as a new battery separator.

  18. The thermal stability and pyrolysis mechanism of boron-containing phenolic resins: The effect of phenyl borates on the char formation

    Science.gov (United States)

    Wang, Shujuan; Wang, Yong; Bian, Cheng; Zhong, Yuhu; Jing, Xinli

    2015-03-01

    Boron-containing phenolic resin (BPR) is a kind of the ablative resins with high-performance. Due to the lack of the exact knowledge concerning the pyrolysis mechanism of BPR, its development and application are greatly impeded. In the present paper, the chemical structure of the cured BPR and its structural evolution at high temperatures are investigated to clarify the reason for the high char yield of BPR. The results indicate that the high char yield of BPR is mainly attributed to the phenyl borates formed during curing, which can block parts of phenolic hydroxyl groups, and effectively inhibit their thermal decomposition reaction. Boron oxide is formed on the surface of carbonization products by the cleavage of O-C bonds from phenyl borates via pyrolysis, which avoids the release of volatile carbon dioxide and reduces the development of micro-structural defects of carbonization products. Introducing boron into PR improves the graphitization degree and graphite crystallites of carbonization products, which promotes the formation of a more ordered glassy carbon during pyrolysis. This study provides a new vision for the understanding of the high char yield of BPR, which makes it possible to develop a new ablative resin through molecular design.

  19. Effect of co-doping of sodium on the thermoluminescence dosimetry properties of copper-doped zinc lithium borate glass system

    International Nuclear Information System (INIS)

    Saidu, A.; Wagiran, H.; Saeed, M.A.; Alajerami, Y.S.M.; Kadir, A.B.A.

    2016-01-01

    The effect of sodium as a co-dopant on the thermoluminescence (TL) properties of copper-doped zinc lithium borate (ZLB: Cu) subjected to Co-60 gamma radiation is reported in this study. TL intensity is enhanced with the introduction of sodium in ZLB: Cu. The obtained glow curve is simple with a single peak. The annealing procedure and the best heating rate for the proposed thermoluminescent dosimeter (TLD) are established, and the phosphor is reusable. The TL response within the dose range of 0.5–1000 Gy is investigated. The results show that the thermal fading behaviour is improved significantly. - Highlights: • Dosimetry properties of an improved TL dosimeter. • The dosimeter is made of lithium borate, modified with ZnO, doped with CuO and co-doped with Na 2 O. • With addition of Na to Cu in the ZLB host, TL yield and sensitivity has significantly enhanced. • The fading behaviour has also been minimized significantly. • The new material is also characterized with the linear dose response, and good reproducibility behaviour.

  20. Evaluation of injectable strontium-containing borate bioactive glass cement with enhanced osteogenic capacity in a critical-sized rabbit femoral condyle defect model.

    Science.gov (United States)

    Zhang, Yadong; Cui, Xu; Zhao, Shichang; Wang, Hui; Rahaman, Mohamed N; Liu, Zhongtang; Huang, Wenhai; Zhang, Changqing

    2015-02-04

    The development of a new generation of injectable bone cements that are bioactive and have enhanced osteogenic capacity for rapid osseointegration is receiving considerable interest. In this study, a novel injectable cement (designated Sr-BBG) composed of strontium-doped borate bioactive glass particles and a chitosan-based bonding phase was prepared and evaluated in vitro and in vivo. The bioactive glass provided the benefits of bioactivity, conversion to hydroxyapatite, and the ability to stimulate osteogenesis, while the chitosan provided a cohesive biocompatible and biodegradable bonding phase. The Sr-BBG cement showed the ability to set in situ (initial setting time = 11.6 ± 1.2 min) and a compressive strength of 19 ± 1 MPa. The Sr-BBG cement enhanced the proliferation and osteogenic differentiation of human bone marrow-derived mesenchymal stem cells in vitro when compared to a similar cement (BBG) composed of chitosan-bonded borate bioactive glass particles without Sr. Microcomputed tomography and histology of critical-sized rabbit femoral condyle defects implanted with the cements showed the osteogenic capacity of the Sr-BBG cement. New bone was observed at different distances from the Sr-BBG implants within eight weeks. The bone-implant contact index was significantly higher for the Sr-BBG implant than it was for the BBG implant. Together, the results indicate that this Sr-BBG cement is a promising implant for healing irregularly shaped bone defects using minimally invasive surgery.

  1. Kinetic and Mechanistic Study of the pH-Dependent Activation (Epoxidation) of Prodrug Treosulfan Including the Reaction Inhibition in a Borate Buffer.

    Science.gov (United States)

    Romański, Michał; Ratajczak, Whitney; Główka, Franciszek

    2017-07-01

    A prodrug treosulfan (T) undergoes a pH-dependent activation to epoxide derivatives. The process seems to involve an intramolecular Williamson reaction (IWR) but clear kinetic evidence is lacking. Moreover, a cis-diol system present in the T structure is expected to promote complexation with boric acid. As a result, the prodrug epoxidation would be inhibited; however, this phenomenon has not been investigated. In this article, the effect of pH on the kinetics of T conversion to its monoepoxide was studied from a mechanistic point of view. Also, the influence of boric acid on the reaction kinetics was examined. The rate constants observed for the activation of T (k obs ) in acetate, phosphate, and carbonate buffers satisfied the equation logk obs  = -7.48 + 0.96 pH. The reaction was inhibited in the excess of boric acid over T, and the k obs decreased with increasing borate buffer concentration. The experimental results were consistent with the inhibition model that included the formation of a tetrahedral, anionic T-boric acid monoester. To conclude, in nonborate buffers, the T activation to (2S,3S)-1,2-epoxybutane-3,4-diol 4-methanesulfonate follows IWR mechanism. A borate buffer changes the reaction kinetics and complicates kinetic analysis. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  2. Host sensitization of Tb3+ ions in tribarium lanthanide borates Ba3Ln (BO3)3 (Ln = Lu and Gd).

    Science.gov (United States)

    Wang, De-Yin; Chen, Teng-Ming; Cheng, Bing-Ming

    2012-03-05

    The vacuum-ultraviolet (VUV) spectroscopic properties of undoped and Tb(3+)-doped borates Ba(3)Ln(BO(3))(3) (Ln = Lu and Gd) with different crystal structures were investigated by using synchrotron radiation. Ba(3)Lu(BO(3))(3) (BLB) crystallizes in a hexagonal structure, whereas Ba(3)Gd(BO(3))(3) (BGB) crystallizes in a trigonal structure. The maximum host absorption for BLB and BGB was found to locate at ~179 and ~195 nm, respectively. Upon host excitation, BLB exhibits an intrinsic broad UV emission centered at 339 nm, which is attributed to the recombination of self-trapped excitons that may presumably be associated with band-gap excitations or molecular transitions within the BO(3)(3-) group. In contrast to BLB, no broad emission but line emission ascribed to a Gd(3+)(6)P(J)-(8)S(7/2) transition was observed in the emission spectrum of BGB. Upon doping of Tb(3+) ions into the hosts of BLB and BGB, an efficient energy transfer from the host excitations to Tb(3+) via host/Gd(3+) emission was observed, showing that host sensitization of Tb(3+) occurs in these rare-earth borates.

  3. Some oxygen-donor di-N-thiocyanato-thorium(IV) and -uranium(IV) bis[hydrotris(pyrazol-1-yl)borate] complexes

    International Nuclear Information System (INIS)

    Ahmed, I.; Bagnall, K.W.; Xing-fu, L.; Po-jung, P.

    1984-01-01

    Di-N-thiocyanato-thorium(IV) and -uranium(IV) bis[hydrotris(pyrazol-1-yl)borate] complexes, M(NCS) 2 [HB(pz) 3 ] 2 .xL :pz = C 3 H 3 N 2 ; x = 1, M = Th, L = tetrahydrofuran (thf); M = U, L = thf, MeCONMe 2 , PMe 2 PhO, PMePh 2 O, or PPh 3 O; x = 2, M = Th, L = MeCONMe 2 , PMe 3 O, PMe 2 PhO, PMePh 2 O, or PPh 3 O; M = U, L = PMe 3 O; x = 1.5, M = Th, L = P(NMe 2 ) 3 O], Th(NCS) 2 [HB(3,5Me 2 -pz) 3 ] 2 and U(NCS) 2 [HB(3,5Me 2 -pz) 3 ] 2 .thf (3,5Me 2 -pz = 3,5-dimethylpyrazol-1-yl) have been prepared. The i.r. and u.v.-visible spectra [uranium(IV) complexes only] of these compounds are reported and the effects of steric crowding on the possible bonding arrangements of the hydrotris(pyrazol-1-yl)borate ligands are discussed in terms of a cone angle factor approach to steric crowding about the metal centres in these complexes. (author)

  4. Bright up-conversion white light emission from Er3+ doped lithium fluoro zinc borate glasses for photonic applications

    Science.gov (United States)

    Vijayalakshmi, L.; Naveen Kumar, K.; Rao, K. Srinivasa; Hwang, Pyung

    2018-03-01

    Various concentrations of Er3+ (0.3, 0.5, 1.0 and 1.5 mol %) doped lithium fluoro zinc borate glasses were synthesized by a traditional melt quenching method. XRD, FTIR and FESEM have been employed to analyze the structural, compositional and morphological analysis respectively. Judd-Ofelt theory has been employed to analyze the intensity parameters (Ωλ, λ = 2, 4 and 6) which can be used to estimate the radiative properties of fluorescent levels of Er3+. We have been observed a strong NIR emission peak at 1.53 μm (4I13/2 → 4I15/2) under the excitation of 980 nm from Er3+: LBZ glasses. Nevertheless, the NIR emission is remarkably enhanced by increasing the Er3+ ions concentration until the optimized concentration of 0.5 mol%. The lifetime of the excited level of 4I13/2 in the NIR emission transition is evaluated and it is found to be1.22 ms from the decay analysis of 0.5 mol% Er3+: LBZ glass. Apart from the NIR emission, a bright up-conversion green emission is observed at 544 nm (4S3/2 → 4I15/2) along with an intense red emission at 659 nm (4F9/2 → 4I15/2) and a weak blue emission (2H9/2 → 4I15/2) under the excitation of 980 nm. Up-conversion emission features were significantly enhanced with increasing the Er3+ concentration up to 1.0 mol%. The combination of the obtained up-conversion emission colors of green, red and blue could generate white light emission. The cool white-light emission from the optimized glass sample has been confirmed from the Commission International de I'Echairage (CIE) 1931 chromaticity diagram analysis and their correlated color temperature (CCT) values. Based on the NIR and up-conversion emission features, Er3+: LBZ glasses could be suggested as promising candidates for optical amplifiers, optical telecommunication windows and white light photonic applications.

  5. Revival of nitrogen-containing bisphosphonate-induced inhibition of osteoclastogenesis and osteoclast function by water-soluble microfibrous borate glass.

    Science.gov (United States)

    Yuan, He; Niu, Li-Na; Jiao, Kai; Pei, Dan-Dan; Pramanik, Chandrani; Li, Ji-Yao; Messer, Regina; Kumar, Satish; Pashley, David H; Tay, Franklin R

    2016-02-01

    Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a serious skeletal complication associated with the long-term oral or intravenous use of nitrogen-containing bisphosphonates (N-BPs). Here, we investigated the effects of an ionic cocktail prepared from water-soluble microfibrous borate glass on neutralizing the inhibitory effects of two heterocyclic N-BPs, risedronate or zoledronic acid, on osteoclastogenesis, apoptosis of differentiated osteoclasts and osteoclast function. Cell growth and proliferation assays were first performed on RAW 264.7 cells to optimize the concentrations of the ionic cocktail and N-BPs to be used for static cell culture. The pre-osteoclasts were then stimulated with RANKL to differentiate into osteoclasts. The effects of the ionic cocktail and N-BPs on osteoclast differentiation, apoptosis and function were subsequently examined using 3 series of experiments conducted at the gene, protein, morphological and functional levels. After concentration optimization, the ionic cocktail was found to partially reverse N-BP-induced inhibition of osteoclastogenesis, stimulation of osteoclasts apoptosis and reduction of osteoclast resorptive activity. Ultrastructural examination of osteoclasts that had been exposed to either N-BP identified classical features of late apoptosis and secondary necrosis, while osteoclasts exposed simultaneously to the concentration-optimized ionic cocktail and N-BPs exhibited only signs of early apoptosis that were possibly reversible. Taken together, the results of the 4 series of experiments indicate that the ionic cocktail produced from dissolution of borate glass dressings has the potential to rescue the adverse effects of heterocyclic N-BPs on osteoclast differentiation and function. These results warrant further confirmation using dynamic cell culture and small animal BRONJ models. Long-term oral and intravenous use of nitrogen-containing bisphosphonates (N-BPs) may result in bisphosphonate

  6. Wound dressings composed of copper-doped borate bioactive glass microfibers stimulate angiogenesis and heal full-thickness skin defects in a rodent model.

    Science.gov (United States)

    Zhao, Shichang; Li, Le; Wang, Hui; Zhang, Yadong; Cheng, Xiangguo; Zhou, Nai; Rahaman, Mohamed N; Liu, Zhongtang; Huang, Wenhai; Zhang, Changqing

    2015-01-01

    There is a need for better wound dressings that possess the requisite angiogenic capacity for rapid in situ healing of full-thickness skin wounds. Borate bioactive glass microfibers are showing a remarkable ability to heal soft tissue wounds but little is known about the process and mechanisms of healing. In the present study, wound dressings composed of borate bioactive glass microfibers (diameter = 0.4-1.2 μm; composition 6Na2O, 8K2O, 8MgO, 22CaO, 54B2O3, 2P2O5; mol%) doped with 0-3.0 wt.% CuO were created and evaluated in vitro and in vivo. When immersed in simulated body fluid, the fibers degraded and converted to hydroxyapatite within ∼7 days, releasing ions such as Ca, B and Cu into the medium. In vitro cell culture showed that the ionic dissolution product of the fibers was not toxic to human umbilical vein endothelial cells (HUVECs) and fibroblasts, promoted HUVEC migration, tubule formation and secretion of vascular endothelial growth factor (VEGF), and stimulated the expression of angiogenic-related genes of the fibroblasts. When used to treat full-thickness skin defects in rodents, the Cu-doped fibers (3.0 wt.% CuO) showed a significantly better capacity to stimulate angiogenesis than the undoped fibers and the untreated defects (control) at 7 and 14 days post-surgery. The defects treated with the Cu-doped and undoped fibers showed improved collagen deposition, maturity and orientation when compared to the untreated defects, the improvement shown by the Cu-doped fibers was not markedly better than the undoped fibers at 14 days post-surgery. These results indicate that the Cu-doped borate glass microfibers have a promising capacity to stimulate angiogenesis and heal full-thickness skin defects. They also provide valuable data for understanding the role of the microfibers in healing soft tissue wounds. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Synthesis and characterization of the lead borate Pb{sub 6}B{sub 12}O{sub 21}(OH){sub 6}

    Energy Technology Data Exchange (ETDEWEB)

    Schoenegger, Sandra; Ortner, Teresa S.; Wurst, Klaus; Heymann, Gunter; Huppertz, Hubert [Innsbruck Univ. (Austria). Inst. fuer Allgemeine, Anorganische und Theoretische Chemie

    2016-11-01

    A lead borate with the composition Pb{sub 6}B{sub 12}O{sub 21}(OH){sub 6} was synthesized through a hydrothermal synthesis, using lead metaborate in combination with sodium nitrate and potassium nitrate. The compound crystallizes in the trigonal, non-centrosymmetric space group P3{sub 2} (no. 145) with the lattice parameters a = 1176.0(4), c = 1333.0(4) pm, and V = 0.1596(2) nm{sup 3}. Interestingly, the data of Pb{sub 6}B{sub 12}O{sub 21}(OH){sub 6} correct the structure of a literature known lead borate with the composition ''Pb{sub 6}B{sub 11}O{sub 18}(OH){sub 9}''. For the latter compound, nearly identical lattice parameters of a = 1176.91(7) and c = 1333.62(12) pm were reported, possessing a crystal structure, in which the localization and refinement of one boron atom was obviously overlooked. The structure of Pb{sub 6}B{sub 12}O{sub 21}(OH){sub 6} is built up from trigonal planar BO{sub 3} and tetrahedral BO{sub 4} groups forming complex chains. The Pb{sup 2+} cations are located between neighboring polyborate chains. The here reported compound Pb{sub 6}B{sub 12}O{sub 21}(OH){sub 6} and ''Pb{sub 6}B{sub 11}O{sub 18}(OH){sub 9}'' were, however, produced under different synthesis conditions. While ''Pb{sub 6}B{sub 11}O{sub 18}(OH){sub 9}'' was synthesized via a hydrothermal synthesis including ethylenediamine and acetic acid, the here reported lead borate Pb{sub 6}B{sub 12}O{sub 21}(OH){sub 6} could be obtained under moderate hydrothermal conditions (240 C) without the addition of organic reagents.

  8. bismuth borate glasses

    Indian Academy of Sciences (India)

    0 ≤ ≤ 2) were measured in the temperature range 297 K up to 629 K and in the frequency range 0.1–100 kHz. The d.c. and a.c. conductivity values and the dielectric loss (tan ) values were found to increase with increasing Sm2O3 content ...

  9. Structural and optical properties of antimony-germanate-borate glass and glass fiber co-doped Eu3+ and Ag nanoparticles.

    Science.gov (United States)

    Zmojda, Jacek; Kochanowicz, Marcin; Miluski, Piotr; Baranowska, Agata; Pisarski, Wojciech A; Pisarska, Joanna; Jadach, Renata; Sitarz, Maciej; Dorosz, Dominik

    2018-04-25

    In the paper analysis of structural and luminescent properties of antimony-germanate-borate glasses and glass fiber co-doped with 0.6AgNO 3 /0.2Eu 2 O 3 are presented. Heat treatment of the fabricated glass and optical fiber (400 °C, 12 h) enabled to obtain Ag nanoparticles (NPs) with average size 30-50 nm on their surface. It has been proofed that silver ions migrate to the glass surface, where they are reduced to Ag 0 nanoparticles. Simultaneously, FTIR analysis showed that heat treatment of the glass and optical fiber increases the local symmetry of the Eu 3+ site. Copyright © 2018. Published by Elsevier B.V.

  10. Negative induced absorption and negative index of refraction for iron doped potash-alumina-borate glasses subjected to thermal-radiation treatment

    Science.gov (United States)

    Salakhitdinov, Amritdin; Ibragimova, Elvira; Salakhitdinova, Maysara

    2018-02-01

    This work experimentally revealed, that 60Co-gamma-irradiation of potash-alumina-borate glasses doped with 1 and 2 mass% of iron oxide to the dose of 1.7 MR in the temperature range of 150-300 °C induced differential optical density changes within - 6 ≤ Δ D ≤ 0 in the wave length range of 300-350 nm, which is characteristic for meta-material. Calculations have shown that variation of optical refraction index within - 0.05 ≤ Δ n ω ≤ 0.05 due to microstructure transformation causes changes in the differential absorption index of the glass - 0.5 < Δ α ω < 0.55.

  11. Theoretical studies of the local structures and spin Hamiltonian parameters for Cu2+ in alkaline earth alumino borate glasses

    Science.gov (United States)

    Guo, Jia-Xing; Wu, Shao-Yi; Kuang, Min-Quan; Peng, Li; Wu, Li-Na

    2018-01-01

    The local structures and spin Hamiltonian parameters are theoretically studied for Cu2+ in alkaline earth alumino borate (XAB, X = Mg, Ca and Sr) glasses by using the perturbation calculations for tetragonally elongated octahedral 3d9 groups. The [CuO6]10‑ groups are subject to the large relative tetragonal elongation ratios of 15.4%, 13.4% and 13.0% for MgAB, CaAB and SrAB glasses, respectively, arising from the Jahn-Teller effect. The decreasing cubic field parameter Dq, orbital reduction factor k and relative elongation ratio with the increase of the radius of alkaline earth ion X from Mg to Ca or Sr are analyzed for the studied systems in a uniform way.

  12. Effect of co-doped SnO{sub 2} nanoparticles on photoluminescence of cu-doped potassium lithium borate glass

    Energy Technology Data Exchange (ETDEWEB)

    Namma, Haydar Aboud; Wagiran, H.; Hussin, R.; Ariwahjoedi, B. [Department of Physics, Universiti Teknologi Malaysia, Skudai 81310, Malaysia and Baghdad College of Economic Sciences University (Iraq); Fundamental and Applied Sciences Department, Universiti Teknologi PETRONAS, 31750 Tronoh (Malaysia)

    2012-09-26

    The SnO{sub 2} co-doped lithium potassium borate glasses doped with 0.05, 0.10, 0.25 and 0.50 mol% of Cu were synthesized by the melt quenching technique. The SnO{sub 2} co-dope was added to the compounds in the amounts of 0.05, 0.10, and 0.20 mol%. The photoluminescent spectrum for different concentrations of copper was studied. It was observed that the intensity of blue emission (450, 490 nm) varies with concentration mol%. In addition, with different concentration of SnO{sub 2} to 0.10 mol% Cu, the influence of the luminescence has been observed to enhance intensity and shifted to blue and red (490, 535 nm) emissions.

  13. Energy response and thermoluminescence properties of lithium potassium borate Glass co-doped with Cu and SnO2 nanoparticles

    Directory of Open Access Journals (Sweden)

    Haydar Aboud

    2017-01-01

    Full Text Available SnO2 nanoparticles doped lithium potassium borate with Cu-doped was prepared by melt-quenching technique. The field emission scanning electron microscope was used to examine morphology of samples. The TLD-Reader 4500 was used to measurement of thermoluminescence. The glow curves position of Cu-doped and co-doped SnO2 glass were recorded at about 205 °C and 215 °C respectively. The linear relationship of dose-TL intensity was observed for both samples. The TLD sensitivity shows that the co-doped SnO2 glass has almost 6 time higher sensitivity compared to Cu-doped glass. It was found that the theoretical calculations are in good agreement with the experimental results for relative energy response. The activation energy and frequency factor of TL glow peak are determined by using the peak shape method.

  14. Lithium borate TLD for determining the backscatter factors for low-energy x rays: comparison with chamber-based and Monte Carlo derived values.

    Science.gov (United States)

    Coudin, D; Marinello, G

    1998-03-01

    Recently, new backscatter factors for low-energy x rays derived from Monte Carlo calculations have been recommended in the UK code of practice for kilovoltage dosimetry published by (IPEMB). As these data, presented as a function of half-value layer, do not take account of the variation of the x-ray spectra for a given HVL, we have undertaken an experimental study in order to determine BSG for the beam qualities provided by a Darpac 2000 therapy unit. A RTL detector such as Li2B4O7:Cu and parallel-plate ion chambers specially designed for low-energy x-ray dosimetry have been used. The results obtained show very good agreement between the TLD and the Monte Carlo calculations, confirming values obtained by other authors with lithium borate TLD. On the contrary, the results obtained with plane-parallel ion chambers show discrepancies up to 9% that are discussed.

  15. Silicate, borosilicate, and borate bioactive glass scaffolds with controllable degradation rate for bone tissue engineering applications. II. In vitro and in vivo biological evaluation.

    Science.gov (United States)

    Fu, Qiang; Rahaman, Mohamed N; Bal, B Sonny; Bonewald, Lynda F; Kuroki, Keiichi; Brown, Roger F

    2010-10-01

    In Part I, the in vitro degradation of bioactivAR52115e glass scaffolds with a microstructure similar to that of human trabecular bone, but with three different compositions, was investigated as a function of immersion time in a simulated body fluid. The glasses consisted of a silicate (13-93) composition, a borosilicate composition (designated 13-93B1), and a borate composition (13-93B3), in which one-third or all of the SiO2 content of 13-93 was replaced by B2O3, respectively. This work is an extension of Part I, to investigate the effect of the glass composition on the in vitro response of osteogenic MLO-A5 cells to these scaffolds, and on the ability of the scaffolds to support tissue infiltration in a rat subcutaneous implantation model. The results of assays for cell viability and alkaline phosphatase activity showed that the slower degrading silicate 13-93 and borosilicate 13-93B1 scaffolds were far better than the borate 13-93B3 scaffolds in supporting cell proliferation and function. However, all three groups of scaffolds showed the ability to support tissue infiltration in vivo after implantation for 6 weeks. The results indicate that the required bioactivity and degradation rate may be achieved by substituting an appropriate amount of SiO2 in 13-93 glass with B2O3, and that these trabecular glass scaffolds could serve as substrates for the repair and regeneration of contained bone defects. Copyright 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.

  16. Conversion of melt-derived microfibrous borate (13-93B3) and silicate (45S5) bioactive glass in a simulated body fluid.

    Science.gov (United States)

    Liu, Xin; Rahaman, Mohamed N; Day, Delbert E

    2013-03-01

    Microfibrous bioactive glasses are showing a considerable capacity to heal soft tissue wounds, but little information is available on the mechanism of healing. In the present study, the conversion of microfibrous borate bioactive glass (diameter = 0.2-5 μm) with the composition designated 13-93B3 (5.5 Na2O, 11.1 K2O, 4.6 MgO, 18.5 CaO, 3.7 P2O5, 56.6 B2O3 wt%) was evaluated in vitro as a function of immersion time in a simulated body fluid (SBF) at 37 °C using structural and chemical techniques. Silicate 45S5glass microfibers (45 SiO2, 24.5 Na2O, 24.5 CaO, 6 P2O5 wt%) were also studied for comparison. Microfibrous 13-93B3 glass degraded almost completely and converted to a calcium phosphate material within 7-14 days in SBF, whereas >85 % of the silica remained in the 45S5 microfibers, forming a silica gel phase. An amorphous calcium phosphate (ACP) product that formed on the 13-93B3 microfibers crystallized at a slower rate to hydroxyapatite (HA) when compared to the ACP that formed on the 45S5 fibers. For immersion times >3 days, the 13-93B3 fibers released a higher concentration of Ca into the SBF than the 45S5 fibers. The fast and more complete degradation, slow crystallization of the ACP product, and higher concentration of dissolved Ca in SBF could contribute to the capacity of the microfibrous borate 13-93B3 glass to heal soft tissue wounds.

  17. Structural and mechanical properties of "peelable" organoaqueous dispersions with partially hydrolyzed poly(vinyl acetate)-borate networks: applications to cleaning painted surfaces.

    Science.gov (United States)

    Natali, Irene; Carretti, Emiliano; Angelova, Lora; Baglioni, Piero; Weiss, Richard G; Dei, Luigi

    2011-11-01

    The preparation and structural characterization of a family of viscoelastic dispersions of borate cross-linked, 80% hydrolyzed poly(vinyl acetate) (80PVAc) in aqueous-organic liquids are presented. Correlations between mechanical properties (from rheological measurements) and the degree and nature of cross-linking (from (11)B NMR spectroscopy) are reported, and the results are used to assess their potential as low-impact cleaning agents for the surfaces of paintings. Because the dispersions can be prepared at room temperature by simple procedures from readily available materials and can contain up to 50% (w/w) of an organic liquid, they offer important advantages over previously described cleaning agents that are based on fully hydrolyzed PVAc (i.e., poly(vinyl alcohol). The mechanical properties of the various aqueous-organic dispersions, as determined quantitatively by rheological investigations and qualitatively by their ease of removal from a solid surface (i.e., the so-called "peel-off" ability) have been tuned systematically by varying the amount of organic liquid, its structure, and the concentrations of borax and 80PVAc. The (11)B NMR studies demonstrate that the concentration of borate ions actively participating in cross-linking increases significantly with the amount of organic liquid in the mixture. The degree of cross-linking remains constant when the 80PVAc and borax concentrations are varied, as long as their ratios are kept constant. Some of the 80PVAc-borax dispersions have been tested successfully as cleaning agents on the surface of a 16th-17th century oil-on-wood painting by Lodovico Cardi, "Il Cigoli", that was covered by a brown patina and on the surface of a Renaissance wall painting by Vecchietta in Santa Maria della Scala, Siena, Italy, that had a degraded polyacrylate coating from a previous conservation treatment.

  18. Verification of effectiveness of borated water shield for a cyclotron type self-shielded; Verificacao da eficacia da blindagem de agua borada construida para um acelerador ciclotron do tipo autoblindado

    Energy Technology Data Exchange (ETDEWEB)

    Videira, Heber S.; Burkhardt, Guilherme M.; Santos, Ronielly S., E-mail: heber@cyclopet.com.br [Cyclopet Radiofarmacos Ltda., Curitiba, PR (Brazil); Passaro, Bruno M.; Gonzalez, Julia A.; Santos, Josefina; Guimaraes, Maria I.C.C. [Universidade de Sao Paulo (HCFMRP/USP), Sao Paulo, SP (Brazil). Faculdade de Medicina. Hospital das Clinicas; Lenzi, Marcelo K. [Universidade Federal do Parana (UFPR), Curitina (Brazil). Programa de Pos-Graduacao em Engenharia Quimica

    2013-04-15

    The technological advances in positron emission tomography (PET) in conventional clinic imaging have led to a steady increase in the number of cyclotrons worldwide. Most of these cyclotrons are being used to produce {sup 18}F-FDG, either for themselves as for the distribution to other centers that have PET. For there to be safety in radiological facilities, the cyclotron intended for medical purposes can be classified in category I and category II, ie, self-shielded or non-shielded (bunker). Therefore, the aim of this work is to verify the effectiveness of borated water shield built for a cyclotron accelerator-type Self-shielded PETtrace 860. Mixtures of water borated occurred in accordance with the manufacturer’s specifications, as well as the results of the radiometric survey in the vicinity of the self-shielding of the cyclotron in the conditions established by the manufacturer showed that radiation levels were below the limits. (author)

  19. High-pressure synthesis and single-crystal structure elucidation of the indium oxide-borate In{sub 4}O{sub 2}B{sub 2}O{sub 7}

    Energy Technology Data Exchange (ETDEWEB)

    Ortner, Teresa S.; Vitzthum, Daniela; Heymann, Gunter; Huppertz, Hubert [Department of General, Inorganic and Theoretical Chemistry, Centre of Chemistry and Biomedicine (CCB), Leopold-Franzens-University Innsbruck (Austria)

    2017-12-29

    The indium oxide-borate In{sub 4}O{sub 2}B{sub 2}O{sub 7} was synthesized under high-pressure/high-temperature conditions at 12.5 GPa/1420 K using a Walker-type multianvil apparatus. Single-crystal X-ray structure elucidation showed edge-sharing OIn{sub 4} tetrahedra and B{sub 2}O{sub 7} units building up the oxide-borate. It crystallizes with Z = 8 in the monoclinic space group P2{sub 1}/n (no. 14) with a = 1016.54(3), b = 964.55(3), c = 1382.66(4) pm, and β = 109.7(1) . The compound was also characterized by powder X-ray diffraction and vibrational spectroscopy. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Pb4(BO3)2(SO4) and Pb2[(BO2)(OH)](SO4): New lead(II) borate-sulfate mixed-anion compounds with two types of 3D network structures

    Science.gov (United States)

    Ruan, Ting-Ting; Wang, Wen-Wen; Hu, Chun-Li; Xu, Xiang; Mao, Jiang-Gao

    2018-04-01

    Two new lead(II) borate-sulfate mixed-anion compounds, namely, Pb4(BO3)2(SO4) and Pb2[(BO2)(OH)](SO4), have been prepared by using high-temperature melt method or hydrothermal reaction. These compounds exhibit two different types of 3D structures composed of the same anionic units of BO3 triangles and SO4 tetrahedra which are interconnected by lead(II) cations. In Pb4(BO3)2(SO4), the lead(II) ions are bridged by borate anions into 3D [Pb4(BO3)2]2+ architectures with 1D tunnels of 8-member rings along the a-axis, which are filled by the sulfate anions. In Pb2[(BO2)(OH)](SO4), the lead(II) ions are interconnected by borate and sulfate anions into 2D Pb-B-O and Pb-S-O layers parallel to the ab plane, respectively, and these layers are further condensed into the 3D lead(II) borate-sulfate framework. TGA and DSC studies indicate that Pb4(BO3)2(SO4) is congruently melting with a melting point of 689 °C whereas Pb2[(BO2)(OH)](SO4) decomposes at approximately 335 °C. UV/Vis/NIR optical diffuse reflectance spectrum measurements reveal the optical band gaps of 4.03 and 4.08 eV for Pb4(BO3)2(SO4) and Pb2[(BO2)(OH)](SO4), respectively. Furthermore, the electronic structures of Pb4(BO3)2(SO4) have also been calculated.

  1. Multimodal emissions from Tb{sup 3+}/Yb{sup 3+} co-doped lithium borate glass: Upconversion, downshifting and quantum cutting

    Energy Technology Data Exchange (ETDEWEB)

    Bahadur, A.; Yadav, R.S.; Yadav, R.V.; Rai, S.B., E-mail: sbrai49@yahoo.co.in

    2017-02-15

    This paper reports the optical properties of Tb{sup 3+}/Yb{sup 3+} co-doped lithium borate (LB) glass prepared by melt quench method. The absorption spectrum of the Yb{sup 3+} doped LB glass contains intense NIR band centered at 976 nm due to {sup 2}F{sub 7/2}→{sup 2}F{sub 5/2} transition. The emission spectra of the prepared glasses have been monitored on excitation with 266, 355 and 976 nm. The Yb{sup 3+} doped glass emits a broad NIR band centered at 976 nm whereas the Tb{sup 3+} doped glass gives off visible bands on excitations with 266 and 355 nm. When the Tb{sup 3+} and Yb{sup 3+} ions are co-doped together, the emission intensity in the visible region decreases whereas it increases in the NIR region significantly. The increase in the emission intensity in the NIR region is due to efficient cooperative energy transfer (CET) from Tb{sup 3+} to Yb{sup 3+} ions. The quantum cutting efficiency for Tb{sup 3+}/Yb{sup 3+} co-doped glass has been calculated and compared for 266 and 355 nm excitations. The quantum cutting efficiency is larger for 355 nm excitation (137%). The Tb{sup 3+}/Yb{sup 3+} co-doped LB glass also emits upconverted visible bands on excitation with 976 nm. The mechanisms involved in the energy transfer have been discussed using schematic energy level diagram. The Tb{sup 3+}/Yb{sup 3+} co-doped LB glass may be used in the optical devices and in solar cell for solar spectral conversion and behaves as a multi-modal photo-luminescent material. - Graphical abstract: The Tb{sup 3+}/Yb{sup 3+} co-doped lithium borate (LB) glass prepared by melt quench method emits upconverted visible emissions through upconversion CET from Yb{sup 3+} to Tb{sup 3+} ions and quantum cutting emissions through downconversion CET from Tb{sup 3+} to Yb{sup 3+} ions. Therefore, the Tb{sup 3+}/Yb{sup 3+} co-doped LB glass may find applications in optical devices and solar cell and behaves as a multi-modal photo-luminescent material. - Highlights: • The Tb{sup 3+}/Yb{sup 3

  2. Influence of Zn injection on corrosion behavior and oxide film characteristics of 304 stainless steel in borated and lithiated high temperature water

    International Nuclear Information System (INIS)

    Wu, Xinqiang; Liu, Xiahe; Han, En-Hou; Ke, Wei

    2012-09-01

    Water chemistry of the reactor coolant system plays a major role in maintaining safety and reliability of light water reactor nuclear power plants (NPPs). Zn water chemistry into pressurized water reactors (PWRs) in order to reduce the radiation buildup in primary coolant system has been widely applied, and the reduction effect has been experimentally confirmed. Zn injection can also lessen the corrosion phenomena in high temperature pressurized water by changing oxide films formed on components materials. Both the radiation buildup and material corrosion resistance in PWR coolant system are closely dependent on the oxide films formed. However, the influence of Zn injection on the chemical composition and structure of the oxide films on their protective properties is still a matter of considerable debate. The influence of Zn injection on corrosion inhibition and environmental degradation has not been fully clarified yet. Therefore, the understanding of corrosion behaviour, oxide film characteristics and their protective property is of significance to clarify the environmentally assisted material failure problems in NPPs. In the present work, oxide films formed on nuclear-grade 304 SS exposed to borated and lithiated high temperature water environments at 300 deg. C up to 4000 h with or without 10 ppb Zn injection were investigated ex-situ. Without Zn injection, the oxide films mainly consisted of Fe 3 O 4 and FeCr 2 O 4 . With Zn injection, ZnFe 2 O 4 and ZnCr 2 O 4 were detected in the oxide films at the initial stage of immersion and ZnCr 2 O 4 became dominant after long-term immersion. It was believed that the above Zn-Fe and Zn-Cr spinel oxides were formed by substitution reactions between Zn 2+ and Fe 2+ . At the initial stage of immersion, water chemistry significantly affected the formation of the oxide films. Once a stable oxide film formed, it is rather difficult to change its structure through changing water chemistry. The potential-pH diagrams for Zn

  3. The influence of CdSe and ZnSe nanoparticles on the optical properties of Sm3+ ions in lead borate glasses

    Science.gov (United States)

    Mallur, Saisudha B.; Heidorn, William D.; Fatokun, Stephen O.; Joshi, Krishna D.; Bista, Sandip S.; Babu, Panakkattu K.

    2017-03-01

    The effect of glass composition and the presence of CdSe/ZnSe nanoparticles (NPs) on the optical absorption and fluorescence of Sm-doped lead borate glasses are studied. Three sets of glass samples xPbO:(99.5-x) B2O3:0.5Sm2O3, x = 29.5-69.5 mol%, xPbO:(96.5-x) B2O3:0.5Sm2O3: 3CdSe/ZnSe, x = 36.5, and 56.5 mol% are prepared. NPs are grown by annealing these glasses just below the glass transition temperature. Average size of both types of NPs increases with annealing time; however, CdSe NPs grew to a larger size range (2 to 20 nm) compared to ZnSe NPs (1 to 16 nm). We analyzed the hypersensitive transition, intensity parameters, radiative transition probability, stimulated emission cross section (σp), and the area ratio of the electric dipole/magnetic dipole transitions of Sm3+. The intensity parameters show a minimum at 11 h annealing for 36.5 mol% and a maximum for the same annealing duration in 56.5 mol% PbO containing CdSe NPs. The σp for 56.5 mol% of PbO with CdSe NPs is found to be a maximum when the average NP size is around 14 nm. ZnSe NPs containing glasses also show significant changes in σp when the average particle size is 16 nm, for 36.5 mol% PbO. Our results suggest that the optical properties of Sm3+ in lead borate glasses are sensitive to its electronic environment which can be modified by varying the base glass composition and/or incorporating large NPs of CdSe/ZnSe. The large σp values that we observe for some of the glass compositions make them attractive materials for photonic devices and photovoltaic applications.

  4. Geological, mineralogical and geochemical characteristics of zeolite deposits associated with borates in the Bigadiç, Emet and Kirka Neogene lacustrine basins, western Turkey

    Science.gov (United States)

    Gündogdu, M. N.; Yalçin, H.; Temel, A.; Clauer, N.

    1996-09-01

    The Bigadiç, Emet and Kirka lacustrine basins of western Turkey may be considered as Tibet-type graben structures that were developed during the Miocene within the Izmir-Ankara suture zone complex. The volcanic-sedimentary successions of these basins are made up of mudstone, carbonate (limestone and dolomite) and detrital rocks, and also of crystal or vitric tuffs about 135 to 200 m thick. The Degirmenli (Bigadiç), Emirler (Bigadiç) Köpenez (Emet) and Karaören (Kirka) tuffs constituting the zeolite deposits are situated beneath four borate deposits (colemanite, ulexite, borax). The most abundant diagenetic silicate minerals are K- and Ca-clinoptilolites in the zeolite deposits, and Li-rich trioctahedral smectites (stevensite, saponite and hectorite) and K-feldspar in the borate deposits. In the Degirmenli, Emirler, Köpenez and Karaören deposits, the following diagenetic facies were developed from rhyolitic glasses rich in K and poor in Na: (glass+smectite), (K-clinoptilolite+opal-CT), (Ca-clinoptilolite+K-feldspar±analcime± quartz) and (K-feldspar+analcime+quartz). K-feldspar which is also rarely associated with phillipsite (Karaören) and heulandite (Degirmenli and Karaören), succeeds clinoptilolite and precedes analcime in these diagenetic facies where dioctahedral smectites, opal-CT and quartz are the latest minerals. No diagenetic transformations exist between clinoptilolite, K-feldspar and analcime that were formed directly from glass. The lateral facies distributions resulted from the differences in salinity and pH of pore water trapped during deposition of the tuffs, but vertical distributions in vitric tuffs seem to have been controlled by the glass/liquid ratio of the reacting system and the permeability or diffusion rate of alkali elements. The Bigadiç, Emet and Kirka zeolite deposits which were formed in saline basins rich in Ca and Mg ions, show similar chemical changes, i.e. loss of alkalis and gain in alkaline-earth elements that have taken

  5. The influence of CdSe and ZnSe nanoparticles on the optical properties of Sm{sup 3+} ions in lead borate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Mallur, Saisudha B.; Heidorn, William D.; Fatokun, Stephen O.; Joshi, Krishna D.; Bista, Sandip S.; Babu, Panakkattu K., E-mail: PK-Babu@wiu.edu [Western Illinois University, Department of Physics (United States)

    2017-03-15

    The effect of glass composition and the presence of CdSe/ZnSe nanoparticles (NPs) on the optical absorption and fluorescence of Sm-doped lead borate glasses are studied. Three sets of glass samples xPbO:(99.5-x) B{sub 2}O{sub 3}:0.5Sm{sub 2}O{sub 3}, x = 29.5–69.5 mol%, xPbO:(96.5-x) B{sub 2}O{sub 3}:0.5Sm{sub 2}O{sub 3}: 3CdSe/ZnSe, x = 36.5, and 56.5 mol% are prepared. NPs are grown by annealing these glasses just below the glass transition temperature. Average size of both types of NPs increases with annealing time; however, CdSe NPs grew to a larger size range (2 to 20 nm) compared to ZnSe NPs (1 to 16 nm). We analyzed the hypersensitive transition, intensity parameters, radiative transition probability, stimulated emission cross section (σ{sub p}), and the area ratio of the electric dipole/magnetic dipole transitions of Sm{sup 3+}. The intensity parameters show a minimum at 11 h annealing for 36.5 mol% and a maximum for the same annealing duration in 56.5 mol% PbO containing CdSe NPs. The σ{sub p} for 56.5 mol% of PbO with CdSe NPs is found to be a maximum when the average NP size is around 14 nm. ZnSe NPs containing glasses also show significant changes in σ{sub p} when the average particle size is ~16 nm, for 36.5 mol% PbO. Our results suggest that the optical properties of Sm{sup 3+} in lead borate glasses are sensitive to its electronic environment which can be modified by varying the base glass composition and/or incorporating large NPs of CdSe/ZnSe. The large σ{sub p} values that we observe for some of the glass compositions make them attractive materials for photonic devices and photovoltaic applications.

  6. Synthesis and photoluminescence properties of Pb{sup 2+} doped inorganic borate phosphor NaSr{sub 4}(BO{sub 3}){sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Chauhan, A. O., E-mail: abhi2718@gmail.com; Koparkar, K. A.; Omanwar, S. K. [Department of Physics, SantGadge Baba Amravati University, Amravati MH, 444602 (India); Bajaj, N. S. [Department of Physics, Toshniwal Art, Commerce and Science College, Sengoan, Hingoli MH (India)

    2016-05-06

    A series of Inorganic borate phosphors NaSr{sub 4}(BO{sub 3}){sub 3} doped with Pb{sup 2+} was successfully synthesized by modified solid state diffusion method. The crystal structure and the phase purity of sample were characterized by powder X-ray diffraction (XRD). The photoluminescence properties of synthesized materials were investigated using spectrofluorometer at room temperature. The phosphor show strong broad band emission spectra in UVA region maximum at 370 nm under the excitation of 289 nm. The dependence of the emission intensity on the Pb{sup 2+} concentration for the NaSr{sub 4}(BO{sub 3}){sub 3} were studied in details. The concentration quenching of Pb{sup 2+} doped NaSr{sub 4}(BO{sub 3}){sub 3} was observed at 0.02 mol. The Stokes shifts of NaSr{sub 4}(BO{sub 3}){sub 3}: Pb{sup 2+} phosphor was calculated to be 7574 cm{sup −1}.

  7. New inorganic (an)ion exchangers with a higher affinity for arsenate and a competitive removal capacity towards fluoride, bromate, bromide, selenate, selenite, arsenite and borate

    KAUST Repository

    Chubar, Natalia

    2011-12-01

    Highly selective materials and effective technologies are needed to meet the increasingly stronger drinking water standards for targeted ionic species. Inorganic ion exchangers based on individual and mixed-metal hydrous oxides (or mixed adsorbents that contain inorganic ion exchangers in their composition) are adsorptive materials that are capable of lowering the concentrations of anionic contaminants, such as H 2AsO 4 -, H 3AsO 3, F -, Br -, BrO 3 -, HSeO 4 -, HSeO 3 - and H 3BO 3, to 10 μg/L or less. To achieve a higher selectivity towards arsenate, a new ion exchanger based on Mg-Al hydrous oxides was developed by a novel, cost-effective and environmentally friendly synthesis method via a non-traditional (alkoxide-free) sol-gel approach. The exceptional adsorptive capacity of the Mg-Al hydrous oxides towards H 2AsO 4 - (up to 200 mg[As]/gdw) is due to the high affinity of this sorbent towards arsenate (steep equilibrium isotherms) and its fast adsorption kinetics. Because of the mesoporous (as determined by N 2 adsorption and SEM) and layered (as determined by XRD and FTIR) structure of the ion-exchange material as well as the abundance of anion exchange sites (as determined by XPS and potentiometric titration) on its surface the material demonstrated very competitive (or very high) removal capacity towards other targeted anions, including fluoride, bromide, bromate, selenate, selenite, and borate. © 2011 IWA Publishing.

  8. Evaluation of precipitates used in strainer head loss testing: Part III. Long-term aluminum hydroxide precipitation tests in borated water

    International Nuclear Information System (INIS)

    Bahn, Chi Bum; Kasza, Ken E.; Shack, William J.; Natesan, Ken; Klein, Paul

    2011-01-01

    Research highlights: → Aluminum hydroxide precipitation boundary is similar to that for amorphous phase. → Various precipitation tests are combined into one map in temperature-'pH + p[Al] T '. → Flocculation tendency of precipitates depend on pH and total Al concentration. → DLVO theory explains qualitatively the dependency of flocculation tendency on pH. - Abstract: Long-term aluminum (Al) hydroxide precipitation tests were conducted in slightly alkaline solutions containing 2500 ppm boron. The solution temperature was cycled to obtain a temperature history more representative of emergency core cooling system temperatures after a loss-of-coolant accident. The observed Al precipitation boundary was close to predicted results for amorphous precipitates, which are higher than the solubility expected for crystalline forms. Bench-scale and loop head loss test results under various conditions were successfully combined into single map in a temperature - 'pH + p[Al] T ' domain, which yielded two bounding lines for Al hydroxide solubility in borated alkaline water that depend on whether or not loop head loss tests with Al alloy coupons are included. Precipitates were observed to form either as fine, cloudy suspensions, which showed very little tendency to settle, or as flocculated precipitates. The flocculation tendency of the precipitates can be qualitatively explained by a colloid stability theory or a phase diagram for protein solutions.

  9. In vitro and in vivo dissolution behavior of a dysprosium lithium borate glass designed for the radiation synovectomy treatment of rheumatoid arthritis.

    Science.gov (United States)

    Conzone, Samuel D; Brown, Roger F; Day, Delbert E; Ehrhardt, Gary J

    2002-05-01

    Dysprosium lithium borate (DyLB) glass microspheres were investigated for use in the radiation synovectomy treatment of rheumatoid arthritis. In vitro testing focused on weight loss and cation dissolution from glass microspheres immersed in simulated synovial fluid (SSF) at 37 degrees C for up to 64 days. In vivo testing was performed by injecting glass microspheres into the stifle joints of Sprague-Dawley rats and monitoring the biodegradability of the microspheres and the tissue response within the joints. The DyLB microspheres reacted nonuniformly in SSF with the majority of lithium and boron being dissolved, whereas nearly all of the dysprosium (>99.7%) remained in the reacted microspheres. Because the DyLB glasses released negligible amounts of dysprosium while reacting with SSF, they are considered safe for radiation synovectomy from the standpoint of unwanted radiation release from the joint capsule. Furthermore, the DyLB microspheres fragmented, degraded, and reacted with body fluids while in the joints of rats without histologic evidence of joint damage. Copyright 2002 Wiley Periodicals, Inc. J Biomed Mater Res 60: 260--268, 2002; DOI 10.1002/jbm.10047

  10. Luminescence properties of Er3+ ions doped bismuth borate glasses for 1.53 \\xB5m broadband optical amplifiers

    Science.gov (United States)

    Mariyappan, M.; Suthanthirakumar, P.; Arunkumar, S.; Marimuthu, K.

    2017-05-01

    A new series of Er3+ ions doped bismuth borate glasses were prepared with the composition (40—x)B2O3 + 20Bi2O3+20Na2O+20CaF2+xEr2O3 (where x= 0.1, 0.25, 0.5, 1 and 2 in wt%). The spectroscopic behaviors of the titled glasses have been examined through absorption, luminescence and decay spectral analysis. Luminescence spectra along with the JO intensity parameters have been used to determine the various radiative properties like transition probability (A), stimulated emission cross-section (σp), lifetimes (τcal, τexp), branching ratios (βR) and effective bandwidth (Δλeff) for the 4S3/2 →4I15/2 and 4I13/2→4I15/2 emission transitions and the results were discussed and reported. By employing the McCumbar theory, absorption and emission cross-sections for the 4I13/2→4I15/2 transition (1.53 μm) were calculated for all the titled glasses. The decay curves of the 4I13/2 level have been measured and the fall in lifetime value with the increase in Er3+ ion content have been studied through the energy transfer process takes place between the nearby Er3+ ions.

  11. Quantifying the mode II critical strain energy release rate of borate bioactive glass coatings on Ti6Al4V substrates.

    Science.gov (United States)

    Matinmanesh, A; Li, Y; Clarkin, O; Zalzal, P; Schemitsch, E H; Towler, M R; Papini, M

    2017-11-01

    Bioactive glasses have been used as coatings for biomedical implants because they can be formulated to promote osseointegration, antibacterial behavior, bone formation, and tissue healing through the incorporation and subsequent release of certain ions. However, shear loading on coated implants has been reported to cause the delamination and loosening of such coatings. This work uses a recently developed fracture mechanics testing methodology to quantify the critical strain energy release rate under nearly pure mode II conditions, G IIC , of a series of borate-based glass coating/Ti6Al4V alloy substrate systems. Incorporating increasing amounts of SrCO 3 in the glass composition was found to increase the G IIC almost twofold, from 25.3 to 46.9J/m 2 . The magnitude and distribution of residual stresses in the coating were quantified, and it was found that the residual stresses in all cases distributed uniformly over the cross section of the coating. The crack was driven towards, but not into, the glass/Ti6Al4V substrate interface due to the shear loading. This implied that the interface had a higher fracture toughness than the coating itself. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Polycomplexes of Hyaluronic Acid and Borates in a Solid State and Solution: Synthesis, Characterization and Perspectives of Application in Boron Neutron Capture Therapy

    Directory of Open Access Journals (Sweden)

    Alexander N. Zelenetskii

    2018-02-01

    Full Text Available In this report, we propose a new polyborate fragment synthesis strategy along the whole chain of the polysaccharide hyaluronic acid (HA to produce boron neutron capture therapy (BNCT compounds. Under high pressure and deformatory solid-state conditions, polymolecular system formation takes place due to association of phase-specific transition components into a more or less distinct microscopic organization. Fourier transform infrared (FTIR spectroscopy shows that HA and polyborates form a network of cyclic polychelate complexes. HA acts as a multidentate ligand using carboxylic and hydroxyl proton donor groups to link oxygen atoms in B–O–B bonds and borate-anions B–O(−: O–H···O, O–H···(−O. With free electron pairs in heteroatoms –O(:···B, –N(:···B, HA can act simultaneously as an electron donor. Nuclear magnetic resonance (NMR with 13C and 1H reveals a preserved complex interaction after both solubilizing and attenuating the HA-polyborate system. Stability of the product in water, low cost, ease of synthesis and scalability of manufacturing indicate that HA-polyborate complexes might have advantages over current chemotherapeutic approaches in creating therapeutic agents for BNCT.

  13. Nano crystalline Bi{sub 2}(VO{sub 5}) phases in lithium bismuth borate glasses containing mixed vanadium-nickel oxides

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, Arti, E-mail: artidabhur@gmail.com; Khasa, S.; Dahiya, M. S. [Department of Physics, Deenbandhu Chhotu Ram University of Science and Technology, Murthal, India-131039 (India); Agarwal, A. [Department of Applied Physics, G. J. University of Science and Technology, Hisar, India-125001 (India)

    2016-05-23

    Glass composition 7V{sub 2}O{sub 5}·23Li{sub 2}O·20Bi{sub 2}O{sub 3}·50B{sub 2}O{sub 3} and x(2NiO·V{sub 2}O{sub 5})·(30-x)Li{sub 2}O·20Bi{sub 2}O{sub 3}·50B{sub 2}O{sub 3}, x=0, 2, 5, 7 and 10, were produced by conventional melt quenching technique. The quenched amorphous glass samples were annealed at temperatures 400°C and 500°C for 6 hours. The Bi{sub 2}(VO{sub 5}) crystallite were grown in all prepared glass matrix. Tn vanadium lithium bismuth borate glass (annealed), the some phrase of V{sub 2}O{sub 5}-crystal were observed along with the nano crystalline Bi{sub 2}(VO{sub 5}) phase. The sharp peaks in FTTR spectra of all annealed compositions were also compatible with the XRD diffraction peaks of the system under investigation. Average crystalline size (D) of the Bi{sub 2}(VO{sub 5}) nano-crystallite was ~30 nm for samples annealed at 400°C and ~42 nm for samples annealed at 500°C. Lattice parameter and the lattice strain for all the samples was also calculated corresponding to the (113) plane of Bi{sub 2}(VO{sub 5}) crystallite.

  14. Heteroleptic metal(II) complexes of hydrotris(methimazolyl)borate and diimines: Synthesis, theoretical calculations, antimicrobial, antioxidant, in vitro cytotoxicity and molecular docking studies.

    Science.gov (United States)

    Jayakumar, S; Mahendiran, D; Rehana, Dilaveez; Kalilur Rahiman, A

    2017-08-01

    A series of heteroleptic metal(II) complexes of formulation [M(Tm)(diimine)](ClO 4 ) (1-8), [Tm = hydrotris(methimazolyl)borate, diimine = 2,2'-bipyridyl or 1,10-phenanthroline and M = Mn(II), Ni(II), Cu(II) or Zn(II)] have been synthesized and characterized by spectroscopic methods. The geometric parameters of the complexes were determined using UV-Vis spectroscopy and DFT calculations. The analyses of HOMO and LUMO have been used to explain the charge transfer within the molecule. Antimicrobial activity of the synthesized heteroleptic complexes were evaluated against two Gram (-ve) (Escherichia coli and Klebsiella pneumoniae) and two Gram (+ve) (Bacillus cereus and Staphylococcus aureus) bacterial, and three fungal (Candida albicans, Candida glabrata and Candida krusei) strains with respect to the standard drugs erythromycin and amphotericin-B. The copper(II) complex 6 showed better scavenging activity against DPPH when compared to other complexes. The cytotoxic activity of copper(II) complexes 5 and 6 against MCF-7 cell line was assessed by MTT assay, which showed exponential responses toward increasing concentration of complexes. In the molecular docking studies, the complexes showed π-π, σ-π, hydrogen bonding, van der Waals and electrostatic interactions with FGFR kinase receptor. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Silicate, borosilicate, and borate bioactive glass scaffolds with controllable degradation rate for bone tissue engineering applications. I. Preparation and in vitro degradation.

    Science.gov (United States)

    Fu, Qiang; Rahaman, Mohamed N; Fu, Hailuo; Liu, Xin

    2010-10-01

    Bioactive glass scaffolds with a microstructure similar to that of dry human trabecular bone but with three different compositions were evaluated for potential applications in bone repair. The preparation of the scaffolds and the effect of the glass composition on the degradation and conversion of the scaffolds to a hydroxyapatite (HA)-type material in a simulated body fluid (SBF) are reported here (Part I). The in vitro response of osteogenic cells to the scaffolds and the in vivo evaluation of the scaffolds in a rat subcutaneous implantation model are described in Part II. Scaffolds (porosity = 78-82%; pore size = 100-500 microm) were prepared using a polymer foam replication technique. The glasses consisted of a silicate (13-93) composition, a borosilicate composition (designated 13-93B1), and a borate composition (13-93B3), in which one-third or all of the SiO2 content of 13-93 was replaced by B2O3, respectively. The conversion rate of the scaffolds to HA in the SBF increased markedly with the B2O3 content of the glass. Concurrently, the pH of the SBF also increased with the B2O3 content of the scaffolds. The compressive strengths of the as-prepared scaffolds (5-11 MPa) were in the upper range of values reported for trabecular bone, but they decreased markedly with immersion time in the SBF and with increasing B2O3 content of the glass. The results show that scaffolds with a wide range of bioactivity and degradation rate can be achieved by replacing varying amounts of SiO(2) in silicate bioactive glass with B2O3. Copyright 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.

  16. Evolutionary divergence of plant borate exporters and critical amino acid residues for the polar localization and boron-dependent vacuolar sorting of AtBOR1

    KAUST Repository

    Wakuta, Shinji

    2015-01-24

    Boron (B) is an essential micronutrient for plants but is toxic when accumulated in excess. The plant BOR family encodes plasma membrane-localized borate exporters (BORs) that control translocation and homeostasis of B under a wide range of conditions. In this study, we examined the evolutionary divergence of BORs among terrestrial plants and showed that the lycophyte Selaginella moellendorffii and angiosperms have evolved two types of BOR (clades I and II). Clade I includes AtBOR1 and homologs previously shown to be involved in efficient transport of B under conditions of limited B availability. AtBOR1 shows polar localization in the plasma membrane and high-B-induced vacuolar sorting, important features for efficient B transport under low-B conditions, and rapid down-regulation to avoid B toxicity. Clade II includes AtBOR4 and barley Bot1 involved in B exclusion for high-B tolerance. We showed, using yeast complementation and B transport assays, that three genes in S. moellendorffii, SmBOR1 in clade I and SmBOR3 and SmBOR4 in clade II, encode functional BORs. Furthermore, amino acid sequence alignments identified an acidic di-leucine motif unique in clade I BORs. Mutational analysis of AtBOR1 revealed that the acidic di-leucine motif is required for the polarity and high-B-induced vacuolar sorting of AtBOR1. Our data clearly indicated that the common ancestor of vascular plants had already acquired two types of BOR for low- and high-B tolerance, and that the BOR family evolved to establish B tolerance in each lineage by adapting to their environments. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists.

  17. 2-Aminoethoxydiphenyl borate activates the mechanically gated human KCNK channels KCNK 2 (TREK-1), KCNK 4 (TRAAK), and KCNK 10 (TREK-2).

    Science.gov (United States)

    Beltrán, Leopoldo; Beltrán, Madeline; Aguado, Ainhara; Gisselmann, Günter; Hatt, Hanns

    2013-01-01

    Two-pore domain K(+) (KCNK, K2P) channels underlie the "leak" (background) potassium conductance in many types of excitable cells. They oppose membrane depolarization and cell excitability. These channels have been reported to be modulated by several physical and chemical stimuli. The compound 2-aminoethoxydiphenyl borate (2-APB) was originally described as an inhibitor of IP3-induced Ca(2+) release but has been shown to act as either a blocker or an activator for several ion channels. Here, we report the effects of this compound on members of the TREK (TWIK related K(+) channels) subfamily of human KCNK channels. We injected Xenopus laevis oocytes with cRNAs (complementary RNAs) encoding several KCNK channels and measured their response using the two-electrode voltage clamp technique. 2-APB was found to be an effective activator for all members of the TREK subfamily (hKCNK2, hKCNK4, and hKCNK10), with the highest efficacy in hKCNK10. We also found that 2-APB was able to activate these channels in cell-excised patches of HEK293 (human embryonic kidney 293) cell transfected with hKCNK4 or hKCNK10, demonstrating direct activation. TREK channels are widely expressed in the central nervous system and peripheral tissues, where they play roles in several key processes. However, little is known regarding their pharmacology; therefore, the identification of a common, stable and inexpensive agonist should aid further investigations of these channels. Additionally, 2-APB has been used to study native receptors in cell systems that endogenously express members of the TREK subfamily (e.g., rat dorsal root ganglia); our results thus warn against the use of 2-APB at high concentrations in these systems.

  18. Rotameric transformations in the photochemistry of TpM(CO)2(η(3)-C3H4R), where Tp = tris(pyrazolyl)borate, M = Mo or W, and R = H or Me.

    Science.gov (United States)

    Thornley, Wyatt A; Bitterwolf, Thomas E

    2015-05-07

    Low energy photolysis of TpM(CO)2(η(3)-C3H4R), where Tp = tris(pyrazolyl)borate, M = Mo or W, and R = 2-H or 2-Me in PVC matrices at 85 K results in exo/gauche isomerism of the allyl ligand. This transformation comes in contrast to the behaviour observed in cyclopentadienyl analogues which undergo exo/endo isomerism. DFT computations reveal an η(3) → η(1)* → η(3) mechanism for the allyl rotameric interconversion where the η(1)*-allyl intermediate is generated upon MLCT excitation.

  19. Synthesis, structure, and electronic structure calculation of a new centrosymmetric borate Pb{sub 2}O[BO{sub 2}(OH)] based on anion-centered OPb{sub 4} tetrahedra

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Feng [College of Chemistry and Chemical Engineering, Xinjiang Normal University, Urumqi 830054 (China); Wang, Li, E-mail: wangliresearch@163.com [College of Chemistry and Chemical Engineering, Xinjiang Normal University, Urumqi 830054 (China); Stoumpos, Constantinos C. [Department of Chemistry, Northwestern University, Evanston, IL 60208 (United States)

    2016-08-15

    The synthesis, structure, and characterization of a new centrosymmetric borate Pb{sub 2}O[BO{sub 2}(OH)] based on anion-centered OPb{sub 4} tetrahedra are reported. Pb{sub 2}O[BO{sub 2}(OH)] crystallizes in monoclinic space group C2/m with a=12.725(7) Å, b=5.698(3) Å, c=7.344(4) Å, β=116.277(6)°. The electronic band structure and density of states of Pb{sub 2}O[BO{sub 2}(OH)] have been calculated via the density functional theory (DFT). Electron density difference calculation indicates that lone-pair electrons of Pb{sup 2+} cation should be stereoactive. - Graphical abstract: An indirect gap compound of Pb{sub 2}O[BO{sub 2}(OH)] with 2D inorganic layers motif based on OPb{sub 4} tetrahedra has been synthesized and full characterized by crystallographic, IR, TG, UV–vis-NIR Diffuse Reflectance, and theoretical calculations. Display Omitted - Highlights: • A centrosymmetric borate Pb{sub 2}O[BO{sub 2}(OH)] was synthesized and characterized. • The crystalstructure, electronic band and density states was analyzed. • The lone-pair electrons of Pb{sup 2+} were proved to be stereoactive.

  20. XRD and FTIR studies the effect of heat treatment and doping the transition metal oxide on LiNbO3 and LiNb3O8 nano-crystallite phases in lithium borate glass system.

    Science.gov (United States)

    Kashif, Ismail; Soliman, Ashia A; Sakr, Elham M; Ratep, Asmaa

    2013-09-01

    Glasses of various compositions in the system 90 Li2B4O7-10 Nb2O5 mixed with T.M ions (where T.M is the transition metal) were prepared by quenching technique. Heat-treatment of the parent glasses was performed at 540, 570 and 620 °C, for 5 and 16 h. The glass structure evolution during the controlled crystallization was examined by XRD and FT-IR spectroscopy analysis. The crystalline phases present in the glass ceramics were identified via X-ray diffraction as a function of heat treatment. The FT-IR data propose for these glasses and heat-treated glass network structures mainly built by: di-, tri-, tetra-, penta-and ortho-borate groups. It was found that the quantitative evolution of these various borate species in the glass structures is influenced by the transition metal. A detailed discussion relating to the N4 evolution with the T.M content was made. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Bis-Indole Derivatives for Polysaccharide Compositional Analysis and Chiral Resolution of D-, L-Monosaccharides by Ligand Exchange Capillary Electrophoresis Using Borate-Cyclodextrin as a Chiral Selector

    Directory of Open Access Journals (Sweden)

    Wen-Bin Yang

    2011-02-01

    Full Text Available A series of aldo-bis-indole derivatives (aldo-BINs was prepared by aromatic C-alkylation reactions of aldoses and indole in acetic acid solution. Common monosaccharides such as glucose, mannose, galactose, fucose, xylose, rhamnose, ribose, arabinose and N-acetylglucosamine were smoothly derivatized to form the UV absorbing aldo-BINs. The use of a capillary electrophoretic method to separate these novel aldo-BIN derivatives was established. The capillary electrophoresis conditions were set by using borate buffer (100 mM at high pH (pH 9.0. The limit of determination was assessed to be 25 nM. The enantioseparation of D, L-pairs of aldo-BINs based on chiral ligand-exchange capillary electrophoresis technology was also achieved by using modified hydroxypropyl-β-cyclodextrin as the chiral selector in the presence of borate buffer. This aldose labeling method was applied successfully to the compositional and configurational analysis of saccharides, exemplified by a rapid and efficient method to simultaneously analyze the composition and configuration of saccharides from the medicinal herbs Cordyceps sinensis and Dendrobium huoshanense.

  2. Combustion synthesis and optical properties of Oxy-borate phosphors YCa4O(BO3)3:RE3+ (RE = Eu3+, Tb3+) under UV, VUV excitation

    International Nuclear Information System (INIS)

    Ingle, J.T.; Gawande, A.B.; Sonekar, R.P.; Omanwar, S.K.; Wang, Yuhua; Zhao, Lei

    2014-01-01

    Graphical abstract: VUV Photoluminescence of YCa 4 O(BO 3 ) 3 : Eu 3+ and YCa 4 O(BO 3 ) 3 : Tb 3+ for PDPs applications. Highlights: • Inorganic Oxy-borate phosphors YCa 4 O(BO 3 ) 3 :Eu 3+ ,Tb 3+ was synthesized by novel solution combustion synthesis. • This single host produces efficient and intense Red and Green color for display applications. • Good agreement with CIE co-ordinates as prescribes by NTCL, for flat panel, PDP display color. • Synthesized materials were characterized using powder XRD, FE-SEM, UV and VUV Spectophotometer. -- Abstract: The inorganic Oxy-borate host phosphors YCa 4 O(BO 3 ) 3 :RE 3+ (RE = Eu 3+ ,Tb 3+ ) were synthesized by a novel solution combustion technique. The synthesis is based on the exothermic reaction between the fuel (Urea) and Oxidizer (Ammonium nitrate). The heat generated in reaction is use for auto combustion of precursors. The structures of the prepared samples were confirmed by powder XRD technique. The photoluminescence properties of the powder samples were investigated under UV and VUV excitation; “The phosphor YCa 4 O(BO 3 ) 3 :Eu 3+ and YCa 4 O(BO 3 ) 3 :Tb 3+ shows strong absorption in UV and VUV region and exhibits intense red and green emission upon excited by 254 nm UV and 147 nm VUV radiation”

  3. Evolution of borate minerals from contact metamorphic to hydrothermal stages: Ludwigite-group minerals and szaibélyite from the Vysoká - Zlatno skarn, Slovakia

    Science.gov (United States)

    Bilohuščin, Vladimír; Uher, Pavel; Koděra, Peter; Milovská, Stanislava; Mikuš, Tomáš; Bačík, Peter

    2017-09-01

    Borate minerals of the ludwigite group (LGM) and szaibélyite in association with hydroxylclinohumite, clinochlore, a serpentine mineral, magnesian magnetite, spinel, magnesite, dolomite and sulphide minerals, occur in a magnesian exoskarn in the R-20 borehole located in the Vysoká - Zlatno Cu-Au porphyry-skarn deposit, located within the Štiavnica Neogene stratovolcano, Western Carpathians, central Slovakia. The skarn is developed along the contact of Miocene granodiorite to quartz-diorite porphyry and a Middle-Upper Triassic dolomite-shale-psammite-anhydrite sedimentary sequence. The boron minerals were investigated by electron probe micro-analyser (EPMA) and micro-Raman techniques. The source of boron could have been from the granodiorite/quartz diorite intrusion; however some supply of B from adjacent evaporite-bearing sediments is also possible. Based on textural and compositional data, the minerals originated during two stages. (1) An early high-temperature, contact-metamorphic and metasomatic stage comprises coarse-crystalline aggregate of LGM (types 1 to 3) in association with hydroxylclinohumite, magnetite, and rarely spinel inclusions in LGM. Compositional variations of LGM show a crystallization sequence from early azoproite [≤17 wt% TiO2; 0.40 atoms pre formula unit (apfu) Ti, which correspond to ≤79 mol% of the Mg2(Mg0.5Ti0.5)O2(BO3) end-member], Ti-Al-rich members of LGM, "aluminoludwigite "[≤14 wt% Al2O3; ≤0.53 apfu, ≤53 mol% of Mg2AlO2(BO3) end-member] and Al-rich ludwigite in the central zone of crystals, to Ti-Al-poor ludwigite in outer parts of crystals. (2) Minerals of the late retrograde serpentinization and hydrothermal stage form irregular veinlets and aggregates, including partial alteration of hydroxylclinohumite to the serpentine-group mineral and clinochlore, replacement of LGM by szaibélyite, formation of the latest generation of Fe-rich, Ti-Al poor ludwigite in veinlets (type 4), and precipitation of dolomite, magnesite and

  4. The gap junction inhibitor 2-aminoethoxy-diphenyl-borate protects against acetaminophen hepatotoxicity by inhibiting cytochrome P450 enzymes and c-jun N-terminal kinase activation

    Energy Technology Data Exchange (ETDEWEB)

    Du, Kuo; Williams, C. David; McGill, Mitchell R.; Xie, Yuchao [Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS (United States); Farhood, Anwar [Department of Pathology, St. David' s North Austin Medical Center, Austin, TX 78756 (United States); Vinken, Mathieu [Department of Toxicology, Center for Pharmaceutical Sciences, Vrije Universiteit Brussels, 1090 Brussels (Belgium); Jaeschke, Hartmut, E-mail: hjaeschke@kumc.edu [Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS (United States)

    2013-12-15

    Acetaminophen (APAP) hepatotoxicity is the leading cause of acute liver failure in the US. Although many aspects of the mechanism are known, recent publications suggest that gap junctions composed of connexin32 function as critical intercellular communication channels which transfer cytotoxic mediators into neighboring hepatocytes and aggravate liver injury. However, these studies did not consider off-target effects of reagents used in these experiments, especially the gap junction inhibitor 2-aminoethoxy-diphenyl-borate (2-APB). In order to assess the mechanisms of protection of 2-APB in vivo, male C56Bl/6 mice were treated with 400 mg/kg APAP to cause extensive liver injury. This injury was prevented when animals were co-treated with 20 mg/kg 2-APB and was attenuated when 2-APB was administered 1.5 h after APAP. However, the protection was completely lost when 2-APB was given 4–6 h after APAP. Measurement of protein adducts and c-jun-N-terminal kinase (JNK) activation indicated that 2-APB reduced both protein binding and JNK activation, which correlated with hepatoprotection. Although some of the protection was due to the solvent dimethyl sulfoxide (DMSO), in vitro experiments clearly demonstrated that 2-APB directly inhibits cytochrome P450 activities. In addition, JNK activation induced by phorone and tert-butylhydroperoxide in vivo was inhibited by 2-APB. The effects against APAP toxicity in vivo were reproduced in primary cultured hepatocytes without use of DMSO and in the absence of functional gap junctions. We conclude that the protective effect of 2-APB was caused by inhibition of metabolic activation of APAP and inhibition of the JNK signaling pathway and not by blocking connexin32-based gap junctions. - Highlights: • 2-APB protected against APAP-induced liver injury in mice in vivo and in vitro • 2-APB protected by inhibiting APAP metabolic activation and JNK signaling pathway • DMSO inhibited APAP metabolic activation as the solvent of 2-APB

  5. REVIEW OF THE OCCURRENCE OF TWO NEW MINERALS IN THE EMET BORATE DEPOSIT, TURKEY: EMETITE, Ca7Na3K(SO49, and FONTARNAUITE, Na2Sr(SO4[B5O8(OH](H2O2

    Directory of Open Access Journals (Sweden)

    Cahit HELVACI

    2015-12-01

    Full Text Available The Emet borate deposit is situated in the middle of the known borate deposits of western Anatolia. Emet is the world biggest colemanite-probertite deposit which is located in the upper section of the volcano-sedimentary sequence of the Emet basin. Emet borate deposit is unique and has unusual mineral associations. The principal minerals in the Emet borate deposit are colemanite with minor probertite, ulexite and hydroboracite. In addition, rare species such as meyerhofferite, veatchite-A, tunellite, terrugite and cahnite occur sporadically. This is the only deposit known to contain any of the minerals veatchite-A, tunellite, teruggite and cahnite. Arsenic minerals (realgar and orpiment are very abundant and spatially related to the borates, indicating a common genetic origin. The mineralogical record of Do¤anlar boreholes is characterized by the alternation of Na-Ca borate (probertite and Na-Ca sulphate (glauberite units including a central halite beds. Colemanite is restricted to the base and top of the sequence in these boreholes and in the whole basin. In this part of the section the major mineral associations probertite-glauberite and halite, with several rare minerals and two new minerals (emetite and fontarnauite were also discovered in these borehole logs. The Emet borate deposit was formed in two separate parts, possibly part of an interconnected lacustrine playa lake, in areas of volcanic activity, fed partly by thermal springs and partly by surface streams. The early colemanite, meyerhofferite, ulexite and teruggite nodules were formed directly from brines penecontemporaneously within the unconsolidated sediments below the sediment/water interface, and continued to grow as the sediments were compacted. Diagenetic alterations include the partial replacement of colemanite by veatchite-A, cahnite, hydroboracite and calcite. The new mineral, emetite, always appears as a diagenetic phase consisting of aggregates of tiny crystals that

  6. Synthesis and Characterization of Network Single Ion Conductors(NSIC) Based On Comb-Branched Polyepoxide Ethers and LithiumBis(allylmalonato)borate

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xiao-Guang; Kerr, John B.

    2004-07-11

    Network single ion conductors (NSICs) based on comb-branch polyepoxide ethers and lithium bis(allylmalonato) borate have been synthesized and thoroughly characterized by means of ionic conductivity measurements, electrochemical impedance and by dynamic mechanical analysis (DMA). The materials have been tested as battery electrolytes by cycling in symmetrical Li/Li half cells and in Li/V{sub 6}O{sub 13} full cells in which the NSIC was used as both binder and electrolyte in the cathode electrode and as the electrolyte separator membrane,. The substitution of the trimethylene oxide (TMO) unit into the side chains in place of ethylene oxide (EO) units increased the polymerion mobility (lower glass transition temperature). However, the ionic conductivity was nearly one and half orders of magnitude lower than the corresponding pure EO based single ion conductor at the same salt concentration. This effect may be ascribed to the lower dielectric constant of the TMO side chains that result in a lower concentration of free conducting lithium cations. For a highly cross-linked system (EO/Li=20), only 47 wt% plasticizing solvent (ethylene carbonate (EC)/ethyl methyl carbonate (EMC), 1/1 by wt) could be taken up and the ionic conductivity was only increased by one order of magnitude over the dry polyelectrolyte while for a less densely crosslinked system (EO/Li=80), up to 75 wt% plasticizer could be taken up and the ionic conductivity was increased by nearly two orders of magnitude. A Li/Li symmetric cell that was cycled at 85 C at a current density of 25{micro}Acm{sup -2} showed no concentration polarization or diffusional relaxation, consistent with a lithium ion transference number of one. However, both the bulk and interfacial impedances increased after 20 cycles, apparently due to continued cross-linking reactions within the membrane and on the surface of the lithium electrodes. A Li/V{sub 6}O{sub 13} full cell constructed using a single ion conductor gel (propylene

  7. Optical absorption, luminescence, and energy transfer processes studies for Dy3+/Tb3+-codoped borate glasses for solid-state lighting applications

    Science.gov (United States)

    Lakshminarayana, G.; Kaky, Kawa M.; Baki, S. O.; Lira, A.; Caldiño, U.; Kityk, I. V.; Mahdi, M. A.

    2017-10-01

    By using melt quenching technique, good optical quality singly doped Dy3+ or Tb3+ and Dy3+/Tb3+-codoped borate glasses were synthesized and studied by optical absorption, excitation, emission and decay lifetimes curve analysis. Following the absorption spectrum, the evaluated Judd-Ofelt (J-O) intensity parameters (Ωλ (λ = 2, 4 and 6)) were used to calculate the transition probability (AR), the branching ratio (βR), and the radiative lifetime (τR) for different luminescent transitions such as 4I15/2 → 6H15/2, 4F9/2 → 6H15/2, 4F9/2 → 6H13/2, 4F9/2 → 6H11/2 and 4F9/2 → 6H9/2,6F11/2 for the 0.5 mol % singly Dy3+-doped glass. The βR calculated (65%) indicates that for lasing applications, 4F9/2 → 6H13/2 emission transition is highly suitable. For all the Dy3+/Tb3+-codoped glasses, Tb3+: 5D3→7F6 emission decay lifetime curves are found to be non-exponential in nature for different concentrations of Dy3+ codoping. Using the Inokuti-Hirayama model, these nonexponential decay curves were analyzed to identify the nature of the energy transfer (ET) processes and here the electric dipole-dipole interaction is dominant for the ET. Based on the excitation and emission spectra and decay lifetimes curve analysis, the cross relaxation and ET processes between Dy3+ and Tb3+ were confirmed. For the 0.5 mol % Tb3+ and 2.0 mol % Dy3+-codoped glass, the evaluated Tb3+→Dy3+ ET efficiency (η) is found to be 45% under 369 nm excitation. Further, for Tb3+/Dy3+ -codoped glasses, an enhancement of Tb3+ green emission is observed up to 1.5 mol % Dy3+ codoping, and this is due to the non-radiative resonant ET from Dy3+ to Tb3+ upon 395 nm excitation. For singly 0.5 mol % Dy3+ or 0.5 mol % Tb3+-doped glass, the calculated color coordinates (x,y) and correlated color temperatures (CCT) represent the neutral white or warm white light regions, whereas Dy3+/Tb3+-codoped glasses (x,y) and CCT values fall in the yellowish green region with respect to the different Dy3

  8. Comparison of Borate Bioactive Glass and Calcium Sulfate as Implants for the Local Delivery of Teicoplanin in the Treatment of Methicillin-Resistant Staphylococcus aureus-Induced Osteomyelitis in a Rabbit Model.

    Science.gov (United States)

    Jia, Wei-Tao; Fu, Qiang; Huang, Wen-Hai; Zhang, Chang-Qing; Rahaman, Mohamed N

    2015-12-01

    There is growing interest in biomaterials that can cure bone infection and also regenerate bone. In this study, two groups of implants composed of 10% (wt/wt) teicoplanin (TEC)-loaded borate bioactive glass (designated TBG) or calcium sulfate (TCS) were created and evaluated for their ability to release TEC in vitro and to cure methicillin-resistant Staphylococcus aureus (MRSA)-induced osteomyelitis in a rabbit model. When immersed in phosphate-buffered saline (PBS), both groups of implants provided a sustained release of TEC at a therapeutic level for up to 3 to 4 weeks while they were gradually degraded and converted to hydroxyapatite. The TBG implants showed a longer duration of TEC release and better retention of strength as a function of immersion time in PBS. Infected rabbit tibiae were treated by debridement, followed by implantation of TBG or TCS pellets or intravenous injection with TEC, or were left untreated. Evaluation at 6 weeks postimplantation showed that the animals implanted with TBG or TCS pellets had significantly lower radiological and histological scores, lower rates of MRSA-positive cultures, and lower bacterial loads than those preoperatively and those of animals treated intravenously. The level of bone regeneration was also higher in the defects treated with the TBG pellets. The results showed that local TEC delivery was more effective than intravenous administration for the treatment of MRSA-induced osteomyelitis. Borate glass has the advantages of better mechanical strength, more desirable kinetics of release of TEC, and a higher osteogenic capacity and thus could be an effective alternative to calcium sulfate for local delivery of TEC. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  9. EPR study of the low-spin state of Ru.sup.3+./sup. in the YAl.sub.3./sub.(BO.sub.4./sub.).sub.3./sub. and EuAl.sub.3./sub.(BO.sub.3./sub.).sub.4./sub. aluminum borates

    Czech Academy of Sciences Publication Activity Database

    Prokhorov, Andriy; Chernush, L.F.; Dyakonov, V.P.; Szymczak, H.; Prokhorov, A.D.

    2016-01-01

    Roč. 420, Dec (2016), s. 285-289 ISSN 0304-8853 R&D Projects: GA MŠk LO1409; GA MŠk LM2015088 Institutional support: RVO:68378271 Keywords : EPR spectra * rare-earth * aluminum borates * spin Hamiltonian parameters * superposition model * low-spin state Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.630, year: 2016

  10. Hydrothermal synthesis and characterization of the praseodymium borate-nitrate Pr[B{sub 5}O{sub 8}(OH)(H{sub 2}O){sub 0.87}]NO{sub 3}.2H{sub 2}O

    Energy Technology Data Exchange (ETDEWEB)

    Ortner, Teresa S.; Huppertz, Hubert [Innsbruck Univ. (Austria). Inst. fuer Allgemeine, Anorganische und Theoretische Chemie

    2017-10-01

    The praseodymium borate-nitrate Pr[B{sub 5}O{sub 8}(OH)(H{sub 2}O){sub 0.87}]NO{sub 3}.2H{sub 2}O was obtained in a hydrothermal synthesis. It crystallizes monoclinically in the space group P2{sub 1}/n (no. 14) with four formula units (Z=4) and unit cell parameters of a=641.9(3), b=1551.8(7), c=1068.4(5) pm, with β=90.54(2) yielding V=1.0643(8) nm{sup 3}. The defect variant constitutes the missing member in the series of isostructural, early rare earth borate-nitrates of the composition RE[B{sub 5}O{sub 8}(OH)(H{sub 2}O){sub x}]NO{sub 3}.2H{sub 2}O [RE=La (x=0; 1), Ce (x=1), Nd (x=0.85), Sm (x=0)]. In addition to powder and single-crystal X-ray diffraction data, the novel borate-nitrate was characterized through IR and Raman spectroscopy.

  11. Hydrothermal synthesis and structural analysis of new mixed oxyanion borates: Ba{sub 11}B{sub 26}O{sub 44}(PO{sub 4}){sub 2}(OH){sub 6}, Li{sub 9}BaB{sub 15}O{sub 27}(CO{sub 3}) and Ba{sub 3}Si{sub 2}B{sub 6}O{sub 16}

    Energy Technology Data Exchange (ETDEWEB)

    Heyward, Carla, E-mail: cheywar@clemson.edu; McMillen, Colin D., E-mail: cmcmill@clemson.edu; Kolis, Joseph, E-mail: kjoseph@clemson.edu

    2013-07-15

    Several new borate compounds, Ba{sub 11}B{sub 26}O{sub 44}(PO{sub 4}){sub 2}(OH){sub 6} (1), Li{sub 9}BaB{sub 15}O{sub 27}(CO{sub 3}) (2), and Ba{sub 3}Si{sub 2}B{sub 6}O{sub 16} (3) were synthesized containing other hetero-oxyanion building blocks in addition to the borate frameworks. They were all prepared under hydrothermal conditions and characterized by single crystal and powder X-ray diffraction, and IR spectroscopy. Crystal data: For 1; space group P2{sub 1}/c, a=6.8909 (14) Å, b=13.629 (3) Å, c=25.851 (5) Å, β=90.04 (3)°; For 2; space group P-31c, a=8.8599 (13) Å, c=15.148 (3) Å; For 3; space group P-1, a=5.0414 (10) Å, b=7.5602 (15) Å, c=8.5374 (17) Å, α=77.15 (3)°, β=77.84 (3)°, γ=87.41 (3)° for 3. Compounds 1 and 2 contain isolated oxyanions [PO{sub 4}]{sup 3−} and [CO{sub 3}]{sup 2−} respectively, sitting in channels created by the borate framework, while structure 3 has the [SiO{sub 4}]{sup 4−} groups directly bonded to the borate groups creating a B–O–Si framework. - Highlights: • Hydrothermal syntheses of three new mixed oxyanion borates are presented. • Ba{sub 11}B{sub 26}O{sub 44}(PO{sub 4}){sub 2}(OH){sub 6} contains isolated [PO{sub 4}]{sup 3−} in voids of the borate framework. • Li{sub 9}BaB{sub 15}O{sub 27}(CO{sub 3}) contains isolated [CO{sub 3}]{sup 2−} in channels created by the framework. • Ba{sub 3}Si{sub 2}B{sub 6}O{sub 16} has direct bonding of [SiO{sub 4}]{sup 4−} and borates creating a B–O–Si framework.

  12. One-dimensional ionic self-assembly in a fluorous solution: the structure of tetra-n-butylammonium tetrakis[3,5-bis(perfluorohexyl)phenyl]borate in perfluoromethylcyclohexane by small-angle neutron scattering (SANS).

    Science.gov (United States)

    Rubinson, Kenneth A; Bühlmann, Philippe; Allison, Thomas C

    2016-04-14

    Fluorous liquids are the least polarizable condensed phases known, and their nonpolar members form solutions with conditions the closest to being in vacuo. A soluble salt consisting of a large fluorophilic anion, tetrakis[3,5-bis(perfluorohexyl)phenyl]borate, and its counterion, tetra-n-butylammonium, dissolved in perfluoromethylcyclohexane produces ionic solutions with extremely low conductivity. These solutions were subjected to small-angle neutron scattering (SANS) to ascertain the solute structure. At concentrations of 9% mass fraction, the fluorophilic electrolyte forms straight, long (>160 Å) self-assembled structures that are, in essence, long, homogeneous cylinders. Molecular models were made assuming a requirement for electroneutrality on the shortest length scale possible. This shows a structure formed from a stack of alternating anions and cations, and the structures fit the experimental scattering well. At the lower concentration of 1%, the stacks of ion pairs are shorter and eventually break up to form solitary ion pairs in the solution. These characteristics suggest such conditions provide an interesting new way to form long, self-assembling ionic nanostructures with single-molecule diameters in free solution onto which various moieties could be attached.

  13. Mixed alkali effect in borate glasses - electron paramagnetic resonance and optical absorption studies in Cu sup 2 sup + doped xNa sub 2 O- (30 - x)K sub 2 O- 70B sub 2 O sub 3 glasses

    CERN Document Server

    Chakradhar, R P S; Rao, J L; Ramakrishna, J

    2003-01-01

    The mixed alkali borate glasses xNa sub 2 O-(30 - x)K sub 2 O-70B sub 2 O sub 3 (5 sup sup 2 B sub 2 sub g) and a weak band on the higher energy side at 22 115 cm sup - sup 1 corresponding to the transition ( sup 2 B sub 1 sub g -> sup 2 E sub g). With x > 5, the higher energy band disappears and the lower energy band shifts slightly to the lower energy side. By correlating the EPR and optical absorption data, the molecular orbital coefficients alpha sup 2 and beta sub 1 sup 2 are evaluated for the different glasses investigated. The values indicate that the in-plane sigma bonding is moderately covalent while the in-plane pi bonding is significantly ionic in nature; these exhibit a minimum with x = 15, showing the MAE. The theoretical values of optical basicity of the glasses have also been evaluated. From optical absorption edges, the optical bandgap energies have been calculated and are found to lie in the range 3.00-3.40 eV. The physical properties of the glasses studied have also been evaluated with respe...

  14. Local-field approximation of homonuclear dipolar interactions in ⁷Li-NMR: density-matrix calculations and random-walk simulations tested by echo experiments on borate glasses.

    Science.gov (United States)

    Storek, Michael; Jeffrey, Kenneth R; Böhmer, Roland

    2014-01-01

    NMR echo techniques have proven to be important to study dynamics in ion conductors and other solid materials. Using the spin-3/2 nucleus (7)Li as a probe, both the quadrupolar and the often neglected homonuclear dipolar interactions modulate the NMR frequency as the ion performs jump processes. Retaining only the local-field term of the many-body Hamiltonian, the impact of the dipolar interaction on various echo experiments was studied using spin dynamics calculations yielding products of dipolar and quadrupolar correlation functions. Using a simple stochastic model these functions were simulated with particular emphasis on the impact of ionic motions and on the conditions under which the dipolar and quadrupolar contributions factorize. The results of the computations and of the random-walk simulations are compared with experimental data obtained for various lithium borate and lithium borophosphate glasses. It is concluded that the local-field approximation is a useful means of treating the Li-Li dipole interactions and that the simple model that we introduce is capable of describing many experimentally observed features. Furthermore, because the dipolar and quadrupolar contributions essentially factorize, a selective determination of the corresponding correlation functions becomes possible. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Cationic metallocene polymerization catalysts based on tetrakis(pentafluorophenyl)borate and its derivatives. Probing the limits of anion `noncoordination` via a synthetic, solution dynamic, structural, and catalytic olefin polymerization study

    Energy Technology Data Exchange (ETDEWEB)

    Jia, L.; Yang, X.; Stern, C.L.; Marks, T.J. [Northwestern Univ., Evanston, IL (United States)

    1997-03-04

    The silyl-functionalized/protected derivatives of the tetrakis(perfluoroaryl)borate anions, B(C{sub 6}F{sub 4}TBS){sub 4}{sup -} and B(C{sub 6}F{sub 4}TIPS){sub 4}{sup -} (TBS = tert-butyldimethylsilyl and TIPS = triisopropylsilyl) have been synthesized, and a series of stable, highly reactive Zr and Th ion-paired methyl and hydride catalysts have been isolated using these anions. In contrast, the analogous B(C{sub 6}F{sub 5}){sub 4}{sup -}-based zirconocene methyl complexes are not stable at room temperature; however, B(C{sub 6}F{sub 5}){sub 4}{sup -}-based zirconocene hydride complexes can be isolated. The relative coordinative ability of the series of fluoroarylborates with respect to metallocene cations has been evaluated on the basis of spectroscopic and reactivity data. The polymerization activity of the zirconocene catalysts reaches a maximum when B(C{sub 6}F{sub 4}TBS){sub 4}{sup -} and B(C{sub 6}F{sub 4}TIPS){sub 4}{sup -} are counteranions, and the polymerization activity of the Zr constrained geometry catalyst reaches a maximum in aromatic solvents due to arene coordination when B(C{sub 6}F{sub 5}){sub 4}{sup -} is the counteranion. 37 refs., 5 figs., 7 tabs.

  16. Enhanced second harmonic generation and photoluminescence in Pr-doped LiNb0.5Ta0.5O3 nanocrystals embedded in a borate based glass

    Science.gov (United States)

    Jaschin, P. W.; Varma, K. B. R.

    2017-08-01

    Non-linear optical properties and photoluminescence exhibited by Pr-doped LiNb0.5Ta0.5O3 nanocrystals embedded in a borate based glass are presented here. The glasses of composition 1.5Li2O-2B2O3-0.5Nb2O5-0.5Ta2O5:xPr6O11 (x = 0.0025, 0.005, and 0.01) were synthesized via the conventional melt-quenching technique, and the nanocrystal growth was induced by subjecting the as-quenched glasses to heat treatment between 530 and 560 °C for 3 h. Coalesced nanocrystals of sizes in the 20-38 nm range, resulting in the formation of dendritic spherulites, were obtained from the isothermal heat treatment. Effect of doping on the structural units of LiNb0.5Ta0.5O3 lattice was analysed by Raman studies, which indicated that Pr ions occupied Li+ vacancies or Nb/Ta antisites. A strong red emission at 620 nm, due to 1D2 → 3H4 electronic transition of Pr3+ ions, was observed upon excitation by a 450 nm radiation. The maximum intensity was exhibited by the composition corresponding to Pr-doping level, x = 0.005, while the crystallization had a pronounced effect on the intensity of the red output. A non-linear optical coefficient as high as 0.77 pm/V (twice that of d36 of potassium dihydrogen phosphate single crystal) was obtained from the bulk glass-nanocrystal composites of the composition in which x = 0.0025.

  17. Synthesis, crystal structure, and properties of Bi{sub 3}TeBO{sub 9} or Bi{sub 3}(TeO{sub 6})(BO{sub 3}): a non-centrosymmetric borate-tellurate(VI) of bismuth

    Energy Technology Data Exchange (ETDEWEB)

    Daub, Michael; Krummer, Michael; Hoffmann, Anke [Institut fuer Anorganische und Analytische Chemie, Albert-Ludwigs-Universitaet, Albertstrasse 21, 79104, Freiburg (Germany); Bayarjargal, Lkhamsuren [Institut fuer Geowissenschaften, Abt. Kristallographie, Goethe-Universitaet, Altenhoeferallee 1, 60438, Frankfurt am Main (Germany); Hillebrecht, Harald [Institut fuer Anorganische und Analytische Chemie, Albert-Ludwigs-Universitaet, Albertstrasse 21, 79104, Freiburg (Germany); Freiburger Materialforschungszentrum FMF, Albert-Ludwigs-Universitaet, Stefan-Meier-Strasse 25, 79104, Freiburg (Germany)

    2017-01-26

    Pale-yellow single crystals of the new borate tellurate(VI) Bi{sub 3}TeBO{sub 9} were obtained by reaction of stoichiometric amounts of Bi{sub 2}O{sub 3}, B{sub 2}O{sub 3}, and Te(OH){sub 6} at 780 C. The non-centrosymmetric crystal structure (P6{sub 3}, Z=2, a=8.7454(16), c=5.8911(11) Aa, 738 refl., 43 param, R1=0.037, wR2=0.093) contains isolated trigonal-planar BO{sub 3} units and nearly undistorted TeO{sub 6} octahedra. The Bi{sup 3+} cations are located in between in octahedral voids. The BiO{sub 6} octahedra are significantly distorted to a [3+3] pattern (2.25/2.50 Aa) due to the ns{sup 2} configuration. According to the structural features, the formula can be written as Bi{sub 3}(TeO{sub 6})(BO{sub 3}). Alternatively, the structure can also be described as hcp of oxygen with Te{sup VI} and Bi{sup III} in octahedral voids and B{sup III} in trigonal- planar voids. The vibrational spectra show the typical features of BO{sub 3} and TeO{sub 6} units with a significant {sup 10}B/{sup 11}B isotopic splitting of the IR-active B-O valence mode (1248 and 1282 cm{sup -1}). The UV/Vis spectrum shows an optical band edge with an onset around 480 nm (2.6 eV). MAS-NMR spectra of {sup 11}B show an anisotropic signal with a quadrupole coupling constant of C{sub Q}=2.55 MHz. and a very small deviation from rotational symmetry (η=0.2). The isotropic chemical shift is 20.1 ppm. The second harmonic generation (SHG) test was positive with an activity comparable to potassium dihydrogen phosphate (KDP). Bi{sub 3}TeBO{sub 9} decomposes in air at 825 C to Bi{sub 2}TeO{sub 5}. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Optical properties of alkaline earth borate glasses

    African Journals Online (AJOL)

    user

    of RO oxides in the glass matrix is small and therefore no significant structural changes might have occurred in the glass network. Urbach's energy refers to the width of the tails of localized states in the forbidden gap of a disordered material. According to. Urbach's rule, optical absorption coefficient near the absorption edge ...

  19. Conversion of borate ions in liquid phase

    International Nuclear Information System (INIS)

    Gode, G.K.; Bernare, A.A.

    1989-01-01

    Isomolar series of aquepus solutions of magnesium chloride and potassium tetraborate at 25 deg C are investigated by the refractometry method. It is established that inderite containing triborate-ion is crystalized from solutions of rather high concentration. In 0.1 M solution reagents form supersaturated solutions with the decreased refractive index against the calculated one. It is supposed that this deviation is caused by partial transformation of tetraborate-ion to triborate-ion under the magnesium ion effect

  20. Optical properties of alkaline earth borate glasses

    African Journals Online (AJOL)

    user

    applications in the field of optical fibers, optoelectronic devices; radiation shields, surgical lasers and their glass ceramic counter parts have wide range of applications (Rajasree et al., 2011; Sharma et al., 2007, Limkitjaroenporn et al., 2010). Boric acid. (H3BO3) form stable glasses with alkaline earth oxides (R= MgO, CaO, ...

  1. Borated concrete for ZPPR fuel storage

    International Nuclear Information System (INIS)

    Gasidlo, J.M.

    1985-01-01

    Fuel handling at the Zero Power Plutonium Reactor (ZPPR) led to two requirements for storage of ZPPR fuel: a low neutron multiplication and shielded storage to minimize personnel doses. Boron-poisoned concrete was chosen as the storge medium with boron frit as the poisoning agent. The calculated effects of water content and boron concentration led to specifying a concrete with a water content that was higher than ordinary concrete. The finite size of the boron frit particles caused concern about reduced effectiveness due to self-shielding. The self-shielding was evaluated using optical path lengths for spheres and tabulated self-shielding for slabs. The results showed that the finite-sized particles were at least 80% as effective as infinitely dilute absorption. Neutron and gamma dose rates measured in the vault verified that personnel could work in the vault on a regular basis without exceeding personnel dose limits. 4 refs., 3 figs., 7 tabs

  2. Microwave properties of vanadium borate glasses

    Indian Academy of Sciences (India)

    Unknown

    The maximum loss was found to be at 15V2O5 mol%. The peak was observed in loss with tempera- ture. Keywords. Semiconducting glass; V2O5–B2O3; microwave properties. 1. Introduction. Ceramics and glasses possessing high relative dielectric constant, ε′ (~ 20 ~ 90), high quality factor, Q (> 3000–. 35000 at 3 GHz), ...

  3. Oxonium ions substituting cesium ions in the structure of the new high-pressure borate HP-Cs{sub 1-x}(H{sub 3}O){sub x}B{sub 3}O{sub 5} (x=0.5-0.7)

    Energy Technology Data Exchange (ETDEWEB)

    Sohr, Gerhard; Heymann, Gunter; Wurst, Klaus; Huppertz, Hubert [Institut fuer Allgemeine, Anorganische und Theoretische Chemie, Leopold-Franzens-Universitaet Innsbruck (Austria); Neumair, Stephanie C. [Tyrolit Schleifmittelwerke Swarovski K.G., Schwaz (Austria); Schmedt auf der Guenne, Joern [Department fuer Chemie und Biologie, Universitaet Siegen (Germany)

    2014-04-07

    The new high-pressure borate HP-Cs{sub 1-x}(H{sub 3}O){sub x}B{sub 3}O{sub 5} (x=0.5-0.7) was synthesized under high-pressure/high-temperature conditions of 6 GPa/900 C in a Walker-type multianvil apparatus. The compound crystallizes in the monoclinic space group C2/c (Z=8) with the parameters a=1000.6(2), b=887.8(2), c=926.3(2) pm, β=103.1(1) , V=0.8016(3) nm{sup 3}, R1=0.0452, and wR2=0.0721 (all data). The boron-oxygen network is analogous to those of the compounds HP-MB{sub 3}O{sub 5}, (M=K, Rb) and exhibits all three structural motifs of borates - BO{sub 3} groups, corner-sharing BO{sub 4} tetrahedra, and edge-sharing BO{sub 4} tetrahedra - at the same time. Channels inside the boron-oxygen framework contain the cesium and oxonium ions, which are disordered on a specific site. Estimating the amount of hydrogen by solid-state NMR spectroscopy and X-ray diffraction led to the composition HP-Cs{sub 1-x}(H{sub 3}O){sub x}B{sub 3}O{sub 5} (x=0.5-0.7), which implies a nonzero phase width. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Alkali-metal/alkaline-earth-metal fluorine beryllium borate NaSr{sub 3}Be{sub 3}B{sub 3}O{sub 9}F{sub 4} with large nonlinear optical properties in the deep-ultraviolet region

    Energy Technology Data Exchange (ETDEWEB)

    Reshak, A. H., E-mail: maalidph@yahoo.com [New Technologies—Research Centre, University of West Bohemia, Univerzitni 8, 306 14 Pilsen (Czech Republic); Center of Excellence Geopolymer and Green Technology, School of Material Engineering, University Malaysia Perlis, 01007 Kangar, Perlis (Malaysia); Huang, Hongwei [School of Materials Science and Technology, China University of Geosciences, Beijing 100083 (China); Kamarudin, H. [Center of Excellence Geopolymer and Green Technology, School of Material Engineering, University Malaysia Perlis, 01007 Kangar, Perlis (Malaysia); Auluck, S. [Council of Scientific and Industrial Research—National Physical Laboratory, Dr. K S Krishnan Marg, New Delhi 110012, India and Physics Department, Indian Institute of Technology - Delhi, Hauz Khas, New Delhi 110016 (India)

    2015-02-28

    The linear optical response and second harmonic generation (SHG) in alkali-metal/alkaline-earth-metal fluorine beryllium borate NaSr{sub 3}Be{sub 3}B{sub 3}O{sub 9}F{sub 4} are investigated by means of density functional theory. Calculations are performed using four types of exchange correlations: Ceperley-Alder local density approximation, Perdew Burke and Ernzerhof general gradient approximation, Engel-Vosko generalized gradient approximation, and the recently modified Becke-Johnson potential (mBJ). The mBJ approach brings the calculated band gap (7.20 eV) in excellent agreement with the experimental one (7.28 eV). The calculated values of the uniaxial anisotropy δε=−0.076 and the birefringence Δn(0)=0.052 indicate considerable anisotropy in the linear optical properties, which makes it favorable for the second harmonic generation. The dominant component of the second harmonic generation is χ{sub 111}{sup (2)}(ω). The value of |χ{sub 111}{sup (2)}(ω)| is about 1.2 pm/V at λ = 1064 nm in agreement with previous calculations. To analyze the origin of the high SHG of NaSr{sub 3}Be{sub 3}B{sub 3}O{sub 9}F{sub 4} single crystals, we have correlated the features of |χ{sub 111}{sup (2)}(ω)| spectra with the features of ε{sub 2}(ω) spectra as a function of ω/2 and ω. From the calculated dominant component |χ{sub 111}{sup (2)}(ω)|, we find that the microscopic first hyperpolarizability, β{sub 111}, the vector components along the dipole moment direction is 0.5 × 10{sup −30} esu at static limit and 0.6 × 10{sup −30} esu at λ = 1064 nm.

  5. Graphite mixed magnesium borate TL dosemeters for beta ray dosimetry

    DEFF Research Database (Denmark)

    Prokic, M; Christensen, Poul

    1984-01-01

    Sintered MgB4O7:Dy dosemeters with graphite contents from 1 to 10% were investigated for application for personnel dosimetry. Data are given on dose response, dose threshold, reproducibility, beta energy response and fading. Furthermore, results from practical field experiments are presented...

  6. Linear and nonlinear optical properties of borate crystals as ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. With the development of the state-of-the-art band calculation scheme and massively parallel pro- cessing in the high performance computing, we are now able to calculate all important physical properties, including (i) the nonlinear susceptibility; (ii) the multiphoton absorption rate; (iii) the birefringence; and (iv).

  7. Silver lead borate glasses doped with europium ions for phosphors ...

    Indian Academy of Sciences (India)

    ... 7 F 1 , 5 D 0 − 7 F 2 , 5 D 0 − 7 F 3 and 5 D 0 − 7 F 4 0 transitions ofEu 3 + ions, respectively. The Commission International de I'Eclairage France 1931 chromaticity coordinates estimatedfrom the emission spectra; it was shown that a 0.5 mol% Eu 2 O 3 doped glass is quite suitable for efficient red phosphors application.

  8. Ultrasonic investigations of some bismuth borate glasses doped with ...

    Indian Academy of Sciences (India)

    3Faculty of Engineering, Civil Engineering Department, Beni-Suef University, Beni-Suef, Egypt. MS received 3 August 2013; revised 27 February 2014. Abstract. The velocities of longitudinal and transverse ultrasonic waves in different compositions of 5Al2O3–. 29Na2O–(66−x)B2O3−xBi2O3 glass system were measured at ...

  9. Silver lead borate glasses doped with europium ions for phosphors

    Indian Academy of Sciences (India)

    From the differential scanning calorimetry studies, the glass transition temperatures ( T g )have been investigated and their values are ranging from 449 to 458 ∘ C. The investigation of Fourier transformer infraredspectra shows the presence of boron atoms in both BO 3 and BO 4 units in the glass network. In addition, it was ...

  10. Spectroscopic study of neodymium doped lead-bismuth-borate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Pasha, Altaf; Dayani, P.; Negalur, Mahesh; Swamy, Manjunatha; Abhiram, J. [Dept of Post Graduate Studies & Research in Physics, The National Degree College, Bangalore (India); Rajaramakrishna, R. [Dept of Post Graduate Studies & Research in Physics, The National Degree College, Bangalore (India); Physics Department, Bangalore University, Bangalore (India)

    2016-05-06

    This paper reports on different physical and optical properties of rare earth doped heavy metal oxide glasses. The glass composition of 10Bi{sub 2}O{sub 3}-30PbO-60B{sub 2}O{sub 3}-xNd{sub 2}O{sub 3} where x = 0, 0.1, 0.2, 0.5 and 1 (in mol %) has been synthesized using melt-quenching technique. Refractive index measurements for these glasses were done and physical parameters were studied. Structural properties of these glasses were analysed through infrared spectra that was recorded between 1600cm{sup −1} and 300cm{sup −1} in transmission mode. The optical absorption spectra were recorded in the wavelength range from 300 to 700 nm. The transitions originated from ground state energy {sup 4}I{sub 9/2}. The energy level analysis has been carried out by considering absorption spectral bands. The results thus obtained are comparable with reports on similar glasses, indicating that the prepared glasses may have potential laser applications.

  11. Optical properties of Nd3+ doped bismuth zinc borate glasses.

    Science.gov (United States)

    Shanmugavelu, B; Venkatramu, V; Ravi Kanth Kumar, V V

    2014-03-25

    Glasses with compositions of (100-x) (Bi2ZnOB2O6) -x Nd2O3 (where x=0.1, 0.3, 0.5, 1 and 2 mol%) were prepared by melt quenching method and characterized through optical absorption, emission and decay curve measurements. Optical absorption spectra have been analyzed using Judd-Ofelt theory. The emission spectra exhibit three peaks at 919, 1063 and 1337 nm corresponding to (4)F3/2 to (4)I9/2, (4)I11/2 and (4)I13/2 transitions in the near infrared region. The emission intensity of the (4)F3/2 to (4)I11/2 transition increases with increase of Nd(3+) concentration up to 1 mol% and then concentration quenching is observed for 2 mol% of Nd(3+) concentration. The lifetimes for the (4)F3/2 level are found to decrease with increase in Nd2O3 concentration in the glasses. The decay curves of the glass up to 0.3 mol% of Nd(3+) exhibit single exponential nature and thereafter the curves become nonexponential nature (0.5, 1 and 2 mol%). The nonexponential curve has been fitted to the Inokuti-Hirayama model to understand the nature of energy transfer process. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Dielectric properties of nickel doped bismuth lithium borate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Dalal, Seema, E-mail: seemadal2014@gmail.com [Department of Physics, Baba Mast Nath University, Asthal Bohr, Rohtak-124001 (India); Department of Physics, Deenbandhu Chhotu Ram University of Science and Technology, Murthal-131039 (India); Dahiya, Sunita [Department of Physics, Baba Mast Nath University, Asthal Bohr, Rohtak-124001 (India); Ashima,; Khasa, S. [Department of Physics, Deenbandhu Chhotu Ram University of Science and Technology, Murthal-131039 (India)

    2016-05-23

    Glasses with composition xBi{sub 2}O{sub 3}•(30-x)Li{sub 2}O•70B{sub 2}O{sub 3} (x = 0, 2, 5, 7 and 10 mol% with codes BLBN1-5 respectively) containing 2 mol% of NiO were prepared via melt-quenching technique and dielectric properties are discussed. The dielectric properties have been studied using impedance spectroscopy. The frequency dependent conductivity investigations for prepared compositions have been carried out using impedance spectroscopy over a frequency range of 1 KHz to 5 MHz and in the temperature range of 300 K-523 K. The complex impedance data have been analyzed by using both the conductivity and the electric modulus formalisms. Standard dielectric behavior is observed in prepared samples. The ac conductivity variations satisfy the Arrhenius relation. The study of the equivalent circuit analysis up to a temperature of 473 K shows a significant change in the equivalent circuit with change in temperature and composition.

  13. Band structure features of nonlinear optical yttrium aluminium borate crystal

    Czech Academy of Sciences Publication Activity Database

    Reshak, Ali H; Auluck, S.; Majchrowski, A.; Kityk, I. V.

    2008-01-01

    Roč. 10, č. 10 (2008), s. 1445-1448 ISSN 1293-2558 Institutional research plan: CEZ:AV0Z60870520 Keywords : Electronic structure * DFF * FPLAPW * LDA Subject RIV: BO - Biophysics Impact factor: 1.742, year: 2008

  14. Synthesis and characterization of cadmium doped lead–borate ...

    Indian Academy of Sciences (India)

    Unknown

    region 400–4000 cm–1 were recorded for all the samples using FT–IR Nexus 670 by KBr pellet technique. 2.5 Density measurement. The density of glass samples was measured using Ar- chimedes's principle. The measurements were done using. Shimadzu Aw 200 balance and xylene as an inert immersion liquid.

  15. Performance Characteristics of Borate Fatty Acid Formulations as Mold Inhibitors

    Science.gov (United States)

    Robert D. Coleman; Vina Yang; Carol A. Clausen

    2013-01-01

    The combination of boric acid (BA) or disodium octaborate tetrahydrate (DOT) and a fatty acid (FA) such as heptanoic, octanoic, and nonanoic acids (C7–C9) is an effective treatment solution for protecting wood structures against mold. BA or DOT alone have substantial potency against insects and decay fungi, but have negligible or no mold inhibitor activity. However,...

  16. Phase separation and dynamical scaling in borate glasses

    International Nuclear Information System (INIS)

    Craievich, A.F.

    1986-01-01

    Quasi-binary B 2 O 3 - PbO - (Al 2 O 3 ) glasses of two different compositions and at several temperature inside the miscibility gap were investigated using small angle X-ray scattering. Measurements were carried out using an X-ray beam from a synchrotron source in spin-hole collimation and the samples were isothermally annealed in situ. (Author) [pt

  17. Ultrasonic investigations of some bismuth borate glasses doped with ...

    Indian Academy of Sciences (India)

    3Faculty of Engineering, Civil Engineering Department, Beni-Suef University, Beni-Suef, Egypt. MS received 3 August 2013 ... materials science. In contrast to the crystalline solids, whose physical properties and structure are essentially understood, there remain some considerable theoretical and experimental difficulties for ...

  18. Hardness and crack behavior of compressed borate glasses

    DEFF Research Database (Denmark)

    Smedskjær, Morten Mattrup; Striepe, S.; Bauer, U.

    Heat-treatment of multivalent ion containing glasses in a hydrogen atmosphere may cause both reduction of the multivalent ions and ionic inward diffusion, resulting in improved glass properties. Bismuth-doped glasses are also interesting objects not only concerning the reduction induced diffusion...

  19. Comparative study of radiation shielding parameters for bismuth borate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Kaundal, Rajinder Singh, E-mail: rajinder_apd@yahoo.com [Department of Physics, School of Physical Sciences, Lovely Professional University, Phagwara, Punjab (India)

    2016-07-15

    Melt and quench technique was used for the preparation of glassy samples of the composition x Bi{sub 2}O{sub 3-}(1-x) B{sub 2}O{sub 3} where x= .05 to .040. XCOM computer program is used for the evaluation of gamma-ray shielding parameters of the prepared glass samples. Further the values of mass attenuation coefficients, effective atomic number and half value layer for the glassy samples have been calculated in the energy range from 1KeV to 100GeV. Rigidity of the glass samples have been analyzed by molar volume of the prepared glass samples. (author)

  20. Silver lead borate glasses doped with europium ions for phosphors ...

    Indian Academy of Sciences (India)

    2017-07-25

    Jul 25, 2017 ... red phosphor in particularly designing mercury-fluorescent lamps, LEDs and plasma displays. Glasses containing silver have been technologically interesting materials for solid- state batteries and electrochemical devices because of their valuable optical properties and high value of ionic con- ductivity [5].

  1. Comparative study of lead borate and bismuth lead borate glass systems as gamma-radiation shielding materials

    International Nuclear Information System (INIS)

    Singh, Narveer; Singh, Kanwar Jit; Singh, Kulwant; Singh, Harvinder

    2004-01-01

    Gamma-ray mass attenuation coefficients have been measured experimentally and calculated theoretically for PbO-B 2 O 3 and Bi 2 O 3 -PbO-B 2 O 3 glass systems using narrow beam transmission method. These values have been used to calculate half value layer (HVL) parameter. These parameters have also been calculated theoretically for some standard radiation shielding concretes at same energies. Effect of replacing lead by bismuth has been analyzed in terms of density, molar volume and mass attenuation coefficient

  2. Oteli-kinogeroi : gde otdõhhajut Dzheims Bond i Borat Sagdijev

    Index Scriptorium Estoniae

    2007-01-01

    Hotellid filmilinal : "Grand Hotel Pupp" Karlovy Vary's, kus filmiti viimast James Bondi filmi; "The Adolphus Hotel" Dallases, mis tuttav Borati seiklustest USAs; Prantsusmaa loss "Chateau de Villette", mis üüriti Da Vinci koodi võteteks; "Park Hyatt Tokyo" hotellis toimus filmi "Tõlkes kaduma läinud" tegevus; "Ocean'c Eleven" - "The Bellagio Resort" jt.

  3. Role of MnO in manganese–borate binary glass systems: a study on ...

    Indian Academy of Sciences (India)

    2017-08-30

    Aug 30, 2017 ... M ŁAPI ´NSKI, M WALAS, M PRZESNIAK-WELENC and L WICIKOWSKI. Department of Solid State Physics, Gdansk University of Technology, 80-233 Gdansk, Poland. ∗. Author for correspondence (tlewandowski@mif.pg.gda.pl). MS received 24 July 2016; accepted 23 November 2016; published online ...

  4. Role of MnO in manganese–borate binary glass systems: a study on ...

    Indian Academy of Sciences (India)

    Fourier transform infrared spectroscopy results revealed the influence of MnO on glass matrix. Decrease of B–O bond-related band intensities has been observed. MnO addition was found to introduce broken [BO 2 O − ] n chains. Differential scanning calorimetry (DSC) measurements presented decreasing T g that indicates ...

  5. Luminescence properties of erbium doped sodium barium borate glass with silver nanoparticles

    Science.gov (United States)

    Rajeshree Patwari, D.; Eraiah, B.

    2018-02-01

    Alteration in the absorption features of rare earth (RE) doped glasses with silver nanoparticles is ever-challenging in photonics. Erbium (Er3+) doped glasses with composition (60-x-y)B2O3-30Na2CO3-10BaO-xEr2O3-yAgCl where (x=0.5, 1.0 and y=1.0 mol %) are synthesized using melt-quenching method. The density is determined by Archimedes principle and molar volumes are calculated. Glass samples were characterized by XRD and UV-Visible spectroscopy. UV-Visible spectra shows eleven prominent absorption peaks centred around 366, 378, 408, 442, 452, 489, 521, 547, 652, 800 and 977 nm equivalent to the rare earth (Er3+) ion transitions. The sample without rare earth shows no peaks which specifies that rare earth ion plays a spirited role in the glass matrix. The glass samples with silver and without rare earth ion shows plasmon peak on heat treatment. The energy band gap values calculated for direct and indirect transitions are in the range of 3.126-3.440eV and 2.58-3.177eV respectively. The refractive indices and Urbach energies are also determined. Photoluminescence spectra are recorded and studied for excitation of the most intense peaks of wavelengths 378 and 521nm. The luminescence of erbium ion is enhanced by the presence of silver when the concentration of rare earth ion is less than that of silver.

  6. Diffusion-Limited Aggregation in Potato Starch and Hydrogen Borate Electrolyte System

    Directory of Open Access Journals (Sweden)

    Tuhina Tiwari

    2013-01-01

    Full Text Available Natural growth of diffusion-limited aggregate (DLA, without any external stimuli, in boric acid doped starch system is reported here. Fractals grown were confirmed to be of diffusion-limited aggregate (DLA pattern having fractal dimension ~1.49. Effect of substrate and humidity on growth pattern has also been discussed. The existence of a different vibration band of H3BO3 in FTIR confirmed that growth structures are related to boric acid. XRD pattern has shown broad peak along with some sharp peaks. Broad peak is related to starch’s amorphous nature, as where intense sharp peaks are due to boric acid.

  7. Neodymium(III) molybdenum(VI) borate, NdBO2MoO4

    OpenAIRE

    Held, Peter; van der Wolf, Benjamin; Bohatý, Ladislav; Becker, Petra

    2011-01-01

    Single crystals of NdBO2MoO4 were obtained from a molybdenum oxide–boron oxide flux under an air atmosphere. The structure features double chains of edge- and face-sharing distorted [NdO10] bicapped square-antiprisms, which are linked by rows of isolated [MoO4] tetrahedra and by zigzag chains of corner-sharing [BO3] groups, all of them running along the b axis. The chains of [NdO10], chains of [BO3] and rows of [MoO4] groups are arranged in layers parallel to the bc plane.

  8. Lithium Gadolinium Borate in Plastic Scintillator as an Antineutrino Detection Material

    Science.gov (United States)

    2010-06-01

    commercial reactor stage is fuel assembly inventory accountancy, reactor operator declarations of power and burnup and auditing by the IAEA. Current...of the groups that first established the correlation between reactor antineutrino flux, thermal power, and fuel burnup has proposed a cubic meter...certainly all escape without depositing much energy. The expected ratio for Gd captures to Li or B is hard to calculate as it depends strongly on the

  9. Plant residues: short term effect on sulphate, borate, zinc and copper adsorption by an acid oxisol

    Directory of Open Access Journals (Sweden)

    Dias Ana Cristi Basile

    2003-01-01

    Full Text Available Laboratory experiments were carried out to examine the effects of plant residues on Cu, Zn, B and S adsorption by an acidic oxisol. The plant residues were: black oats (Avena strigosa, oil seed radish(Raphanus sativus, velvet beans (Stizolobium cinereum, and pigeon pea (Cajanus cajan collected at flowering stage. Plant residues increased Cu and Zn adsorptions and decreased B and S adsorptions. The results indicated that for short term effect plant residues decreased the availabilities of Cu and Zn through metal organic complex reactions and increased availabilities of S and B through competition with organic anions by the adsorption sites on soil.

  10. Synthesis and optical property of holmium doped Lithium lead borate glasses

    Science.gov (United States)

    Usharani, V. L.; Eraiah, B.

    2017-05-01

    The new glass system 60B2O3-30PbO-(10-x)Li2O-xHo2O3 (where x =0, 0.1, 0.3 and 0.5 mol%) were prepared by conventional melt quenching method. The XRD spectrum confirms the amorphous nature of the sample. The density of these glasses is measured by using Archimedes principle, the values range from 4.23 g/cm-3 to 4.34 g/cm-3 and the corresponding molar volumes are calculated. The optical absorbance studies were carried out on these glasses in the wavelength range of 200nm to 1100nm. The measured optical direct band gap energies were in the range of 3.072eV to 3.259eV and the optical indirect band gap energies in the range of 2.658eV to 2.846eV. The refractive indices of these glasses were measured by using Abbe refractometer and the corresponding polarizabilities of oxide ions are calculated by using Lorentz-Lorentz relations.

  11. Role of MnO in manganese–borate binary glass systems: a study on ...

    Indian Academy of Sciences (India)

    2017-08-30

    Aug 30, 2017 ... Abstract. Structural and thermal properties of xMnO−(100−x)B2O3 (where x = 40, 50 and 60 mol%) glass samples have been investigated with the employment of various techniques. Fourier transform infrared spectroscopy results revealed the influence of MnO on glass matrix. Decrease of B–O ...

  12. Role of MnO in manganese–borate binary glass systems

    Indian Academy of Sciences (India)

    Structural and thermal properties of x MnO−( 100 − x )B 2 O 3 (where x = 40 , 50 and 60 mol%) glass samples have been investigated with the employment of various techniques. Fourier transform infrared spectroscopy results revealed the influence of MnO on glass matrix. Decrease of B–O bond-related band intensities has ...

  13. Structural and morphological studies lead borate glasses by melt quenching technique

    International Nuclear Information System (INIS)

    Jetruth Mary Alphonsa, K.; Sumathi, T.

    2013-01-01

    The studies of oxide glasses have gained attention due to their structural features. This type of glass has some remarkable features such as low melting temperature, impressive wide glass formation region, high resistance against devitrification and high refractive index. 60B 2 O 3 -(30-x) PbO-xK 2 O/Li 2 O glasses were prepared using the melt quenching technique because of its rapid glass forming ability. The amorphous nature of the prepared glass samples were confirmed by XRD (X-Ray diffraction technique) and SEM (Scanning Electron Microscopy). The quantitative analysis has been carried out in order to obtain more information about the structure of these glasses using FT-IR (Fourier transform infrared spectroscopy). (author)

  14. Structural properties of lithium borate glasses doped with rare earth ions

    Directory of Open Access Journals (Sweden)

    Thomazini D.

    2001-01-01

    Full Text Available This paper presents the study on lithium triborate glass (LBO in the system (1-x|3B2O3.Li2O| (xNb2O5 yPr3+ zYb3+ wNd3+ with 0 <= x <= 20 mol% (y, z and w in mol%. The samples were studied by Raman spectroscopy, infrared absorption and differential thermal analysis. Pr3+-doped LBO and Pr3+/Yb3+-doped LBO samples show an increase of the glass transition and crystallization temperatures and a decrease of the fusion temperature associated with the increase of the praseodymium concentration in the LBO matrix. For the Nd3+-doped LBO and Pr3+/Yb3+-doped (LBO+Nb2O5 samples, a decrease of the glass transition temperature of the samples was observed. The increase of the rare earth doping leads to an increase of the difference between the glass transition and the crystallization temperatures. From infrared analysis it was possible to identify all the modes associated to the B-O structure. The NbO6 octahedra was also identified by IR spectroscopy for samples with x=5, 10, 15 and 20 mol% and y=0.05, z=1.1 mol%. Raman spectroscopy shows the presence of boroxol rings, tetrahedral and triangular coordination for boron. For samples containing niobium, the Raman spectra show the vibrational mode associated with the Nb-O bond in the niobium octahedra (NbO6.

  15. Passivation of iron in solutions containing borate using rotating ring-disc measurements

    OpenAIRE

    Martini, Emilse M.A.; Muller, Iduvirges L.

    1999-01-01

    Investigou-se o comportamento eletroquímico do ferro em soluções neutras de perclorato de sódio contendo pequenas concentrações de borato de sódio, através da técnica de voltametria cíclica e empregando-se eletrodo rotatório de disco e anel. Nas soluções de perclorato, a passivação do ferro ocorreu após o pico anódico correspondente à zona ativa, no qual foi observada a dissolução de espécies Fe2+ e Fe3+. Quando é adicionado borato à solução, tanto a densidade de corrente do pico anódico quan...

  16. Barium and calcium borate glasses as shielding materials for x rays and gamma rays

    DEFF Research Database (Denmark)

    Singh, H.; Singh, K.; Sharma, G.

    2003-01-01

    Values of the gamma-ray, mass attenuation coefficient and the effective atomic number have been determined experimentally for xBaO.(1-x) B2O3 (x=0.24, 0.30, 0.34,0.40 and 0.44) and xCaO. (I-x)B2O3 (x=0.30 and 0.40) glasses at photon energies 356, 511, 662, 1173, and 1332 keV It is pointed out...

  17. Demonstration of the Coagulation and Diffusion of Homemade Slime Prepared under Acidic Conditions without Borate

    Science.gov (United States)

    Isokawa, Naho; Fueda, Kazuki; Miyagawa, Korin; Kanno, Kenichi

    2015-01-01

    Poly(vinyl alcohol) (PVA) precipitates in many kinds of aqueous salt solutions. While sodium sulfate, a coagulant for PVA fiber, precipitates PVA to yield a white rigid gel, coagulation of PVA with aluminum sulfate, a coagulant for water treatment, yields a slime-like viscoelastic fluid. One type of homemade slime is prepared under basic…

  18. Spectroscopic properties and luminescence behaviour of europium doped lithium borate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Anjaiah, J., E-mail: anjaiah.juluru@gmail.com [Department of Physics, The University of Dodoma, Tanzania, East Africa (Tanzania, United Republic of); Department of Physics, Geethanjali College of Engineering and Technology, Keesara, RR Dist., Hyderabad 501 301 (India); Laxmikanth, C. [Department of Physics, The University of Dodoma, Tanzania, East Africa (Tanzania, United Republic of); Veeraiah, N. [Department of Physics, Acharya Nagarjuna University, Nagarjuna Nagar, Guntur 522 510, AP. (India)

    2014-12-01

    Li{sub 2}O–MO–B{sub 2}O{sub 3} (MO=ZnO, CaO and CdO) glasses doped with europium are prepared by using the melt quenching technique to study their absorption and luminescence properties to understand their lasing potentialities. The XRD pattern of the glasses confirmed the amorphous nature and the IR spectra reveal the presence of BO{sub 3} and BO{sub 4} units in the glass network. Judd–Ofelt intensity parameters Ω{sub λ} (λ=2, 4, 6) are evaluated from the intensities of various absorption bands of optical absorption spectra. The J–O parameters have been used to calculate transition probabilities (A), lifetime (τ{sub R}), branching ratios (β{sub R}) and stimulated emission cross-section (σ{sub P}) for the {sup 5}D{sub 0}→{sup 7}F{sub J} (J=1–4) transitions of the Eu{sup 3+} ions. The decay from the {sup 5}D{sub 0} level of Eu{sup 3+} ions in these glasses has been measured and analysed. Branching ratios and stimulated emission cross-sections measured for all these glasses show that the {sup 5}D{sub 0}→{sup 7}F{sub 1} transition under investigation has the potential for laser applications. The high stimulated emission cross-section and branching ratios from the present glasses suggests their potential for infra red lasers. The study of the thermoluminescence is also carried out and the data suggests that the CdBEu glass is suitable for thermoluminescence emission output among the three Eu{sup 3+} doped glasses.

  19. Barium and calcium borate glasses as shielding materials for x rays and gamma rays

    DEFF Research Database (Denmark)

    Singh, H.; Singh, K.; Sharma, G.

    2003-01-01

    Values of the gamma-ray, mass attenuation coefficient and the effective atomic number have been determined experimentally for xBaO.(1-x) B2O3 (x=0.24, 0.30, 0.34,0.40 and 0.44) and xCaO. (I-x)B2O3 (x=0.30 and 0.40) glasses at photon energies 356, 511, 662, 1173, and 1332 keV It is pointed out tha...

  20. Optical and Physical Investigations of Lanthanum Bismuth Borate glasses doped with Ho2O3

    Science.gov (United States)

    Ramesh, P.; Jagannath, G.; Eraiah, B.; Kokila, M. K.

    2018-02-01

    Holmium doped 10La2O3-15Bi2O3-(75-x) B2O3 (Ho3+: LBB) glasses have been prepared by melt quench technique and the impact of holmium ions concentration on optical and physical properties of present glasses have been examined. Ho3+ dependent density, molar volume, refractive index, rare earth ion concentration, polaron radius, inter ionic distance, field strength and energy band gap are calculated and tabulated. Amorphous nature of the all glasses has been confirmed by XRD patterns. The room temperature (RT) Uv-Vis absorption spectrum doped with 1 mol% of Ho2O3 exhibit eight prominent bands centred at 895, 641, 537, 486, 472, 467, 451 and 416 due to transition between ground state to various excited states. The results show that, the density is increases and molar volume of the glasses is decreases with an increase in Ho2O3 concentration and consequently generate more non-bridging oxygen (NBOs) in the glass matrix. The Urbach energy is increases with holmium concentration which exemplifies the degree of disorder present in the LBB glasses. The considerable increase in field strength observed in present glasses is attributed to occurrence of strong bridge between Ho3+ and B- ions and this strong bridge is possibly due to the displacement between Ho3+ and oxygen atoms which are generated from the conversion BO3-BO4 units.

  1. Long-term phytoavailability of soil-applied organo-borates

    International Nuclear Information System (INIS)

    Adriano, D.C.; Kaplan, D.I.; Burkman, W.G.; Mills, G.L.

    1988-01-01

    Sodium tetraphenylboron (NaTPB) is expected to be used in large quantities to separate radiocesium from high-level nuclear wastes. Greenhouse experiments were conducted to determine the long-term effects of NaTPB, diphenylboric acid (DPBA, a major degradation by-product of NaTPB) and boric acid (BA) on the extractability of soil B and plant B nutrition. Sorgrass (Sorghum vulgare sudanense Hitchc. Dub-L-Graze) was planted in sandy and loamy sandy soils in two separate 2-yr studies. Results indicate that initial differences between effects of the B sources on biomass, plant B concentration, plant B uptake and hot-water extractable B disappeared after the first harvest, while differences among these parameters due to soil type and application rate remained throughout the experiments. Extractable soil and plant B concentrations tended to decrease more gradually in the loamy sand than in the sandy soil. Plant toxicity from organic sources was noted only during the first harvest while BA had no adverse effects. Both NaTPB and DPBA reduced biomass, the former more than the latter. Initially, plant B concentrations were higher in NaTPB than BA treatments. The cumulative percentage of soil-applied B removal after 2 yr by sorgrass remained fairly similar, 20.0 +/- 1.7% (1SD) among B sources and application rates. This suggests that a large fraction of B applied to the soil was not taken up by the plant, presumably due to soil fixation. Biphenyl, another major breakdown product of NaTPB, had no effect on sorgrass growth, tissue B concentration, and soil B concentration

  2. Synthesis and photocatalytic properties of α-ZnWO4 nanocrystals in tungsten zinc borate glasses

    Directory of Open Access Journals (Sweden)

    Tatsuya Ida

    2014-09-01

    Full Text Available Tungsten oxide (WO3-containing glasses of WO3–ZnO–B2O3 were prepared using a conventional melt quenching method, and α-ZnWO4 nanocrystals were synthesized through the crystallization of glasses. A glass with the composition of 20WO3–50ZnO–30B2O3 showed the bulk crystallization of α-ZnWO4 nanocrystals with a diameter of ∼10 nm. Broad and asymmetric emission peaks were observed at the wavelength of λ ∼ 475 nm, i.e., blue emissions, in the photoluminescence spectra for the samples with α-ZnWO4 nanocrystals. From the degradation of the intensity of optical absorption under ultraviolet light (λ = 254 nm irradiations for the solution consisting of crystallized particles with α-ZnWO4 nanocrystals and methylene blue, it was clarified that α-ZnWO4 nanocrystals formed have photocatalytic activities. The formation of α-ZnWO4 nanocrystals is discussed from the viewpoint of the glass-forming tendency.

  3. Effect of cement kiln dust and gamma irradiation on the ultrasonic parameters of HMO borate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Abd elfadeel, G. [Physics Department, Faculty of Science, Al-Azhar University, Assiut 71524 (Egypt); Saddeek, Yasser B., E-mail: ysaddeek@gmail.com [Physics Department, Faculty of Science, Al-Azhar University, Assiut 71524 (Egypt); Mohamed, Gehan Y. [Experimental Nuclear Physics Department, Nuclear Research Center, Atomic Energy Authority, Post Office No. 13759, Cairo (Egypt); Mostafa, A.M.A. [Physics Department, Faculty of Science, Al-Azhar University, Assiut 71524 (Egypt); Shokry Hassan, H. [Advanced Technology and New Materials Research Institute, City of Scientific Research and Technology Applications, New Borg El-Arab City, Alexandria 21934 (Egypt)

    2017-03-01

    Glass samples with the chemical formula x CKD—(100 − x) (5Na{sub 2}O–65 B{sub 2}O{sub 3}–9 Bi{sub 2}O{sub 3}–21PbO), (0 ⩽ x ⩽ 32 mol%) were prepared. The density and the ultrasonic estimations of the investigated glasses were analyzed at room temperature before and after the impact of two dosages of gamma irradiation to study the effect of both CKD and gamma radiation. It was found that the density, and the ultrasonic parameters are sensitive to the variety of the content of CKD and the effect of γ-radiation. Replacement of oxides with higher atomic weights such as Bi{sub 2}O{sub 3} and PbO by CKD decreases the density. Analysis of the behavior of the ultrasonic parameters demonstrates that creation of CaO{sub 6} and SiO{sub 4} on one hand and an alternate transformation between BO{sub 4} and BO{sub 3} structural units, on the other hand, affect the increase of the ultrasonic velocities and the elastic moduli. Moreover, the density and the ultrasonic parameters decrease somewhat with the increase of the doses of γ-irradiation. The variations of the previous physical parameters can be referred to the creation of radiation imperfections, which occupied the voids inside the glass structure.

  4. Impedance spectroscopic characterization of Sm2O3 containing lithium borate glasses.

    Science.gov (United States)

    Ramteke, D D; Gedam, R S

    2014-12-10

    27.5 Li2O-(72.5-X) B2O3-X Sm2O3 (X=0.5, 1, 1.5 and 2) were prepared by conventional melt quench technique. Impedance spectroscopy (IS) is used to study the electrical properties of these prepared glasses. Modulus formalism is introduced to study relaxation behaviour of these glasses. Scaling model shows the good overlap of data on single master curve which suggests that conduction mechanism in these glasses is compositional dependent. Variation of dielectric constant and dielectric loss with the addition of Sm2O3 and frequency are discussed here. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. HIGH-FREQUENCY DIELECTRIC-PROPERTIES OF ALKALI AND ALKALI-HALIDE BORATE GLASSES

    NARCIS (Netherlands)

    VERHOEF, AH; DENHARTOG, HW

    Time domain reflectometry (TDR) measurements have been carried out on glasses of compositions (B2O3)1-x(Li2O)x and (B2O3)1-x-y(Li2O)x(Li2Cl2)y. Dielectric spectra have been obtained in the frequency range of 5 MHz to 10 GHz and in temperature intervals from room temperature up to values in the

  6. Structure and magnetic properties of ultrafine lithium ferrite crystallized from a borate glass

    Science.gov (United States)

    El Shabrawy, S.; Bocker, C.; Tzankov, D.; Georgieva, M.; Harizanova, R.; Rüssel, C.

    2017-04-01

    A glass with the mol. % compositions 51.7 B2O3/9.3 K2O/1 P2O5/27.6 Li2O/10.4 Fe2O3 was crystallized at temperatures in the range from 400 to 540 °C for different periods of time (2-12 h). X-ray diffraction showed cubic Li ferrite with a spinel structure, LiFe5O8, with small crystallites with sizes in the range from 3 to 31 nm. While the samples crystallized at 440, 480, and 500 °C reveal a disordered phase, crystallization at 540 °C indicates a phase transformation to the ordered state. Magnetization curves showed that the samples crystallized at 440 °C are superparamagnetic with very low maximum magnetization, while the samples crystallized at 480 and 500 °C show thin clear S-shaped magnetization curves with zero coercivity and hence are also superparamagnetic. By contrast, the sample crystallized at 540 °C shows a coercive field of 40 Oe and thus is ferrimagnetic. The magnetic properties can be tailored by the size of the ferrite crystals and hence by the crystallization conditions.

  7. Luminescent Stability of Hybrids Based on Different Borate Glass Matrix’s and Organic Metal Complexes

    Science.gov (United States)

    Petrova, Olga; Avetisov, Roman; Akkuzina, Alina; Anurova, Mariia; Mozhevitina, Elena; Khomyakov, Andrew; Taydakov, Ilya; Avetissov, Igor

    2017-08-01

    The stability of the luminescent properties of new hybrid materials based on 8-oxyquinoline metal (Li, Rb, Sr) complexes and Eu complex with phenanthroline and low-melting Pb-based inorganic glass matrixes under conditions of prolonged exposure under ambient conditions and heating above the glass transition temperature of the matrix’s has been investigated.

  8. Infrared spectroscopy of network and cation dynamics in binary and mixed alkali borate glasses

    NARCIS (Netherlands)

    Verhoef, A.H; Hartog, H.W.den

    Infrared reflectance spectra of twenty different glasses of the type (B2O3)(1-x-y)(Li2O)(x)(Cs2O)(y) have been measured in the frequency range of 10-5000 cm(-1). From these spectra, infrared absorbance and dielectric spectra have been calculated using the Kramers-Kronig inversion technique. The

  9. Emission properties of Ce-doped alkaline earth borate glasses for scintillator applications

    Science.gov (United States)

    Torimoto, Aya; Masai, Hirokazu; Okada, Go; Kawaguchi, Noriaki; Yanagida, Takayuki

    2017-11-01

    We investigate the photoluminescence (PL) and X-ray-induced luminescence properties of 0.1 mol% Ce-doped MO-B2O3 (M = Ca, Sr, and Ba) glasses. We also determine the Ce3+/(Ce3++Ce4+) ratio by X-ray absorption near-edge structure analyses. The emission intensities of PL, X-ray scintillation, and thermally stimulated luminescence (TSL) depend on the host glass composition. The order of the PL intensity from highest to lowest is as follows: Ca-substituted glass, Ba-substituted glass, and Sr-substituted glass. Our results suggest that the optical absorption edge and quantum yield (QY) are influenced by the local coordination state of Ce3+, which, in turn, is likely to be affected by the optical basicity. The order of the X-ray scintillation intensity from highest to lowest is reverse of that of the PL intensity. This is probably because the interaction probability of X-rays with matter depends on the effective atomic number of the material and the effective atomic number has a stronger influence on the scintillation intensity than does the QY. Though the TSL glow curves reveal that the density and energy depth of the trap sites depend on the substituted alkaline earth oxides, we are unable to correlate the electron spin resonance (ESR) spectra with the TSL results. Therefore, it is considered that the ESR active sites are not responsible for the TSL in these systems.

  10. Preparation of Ferroelectric KNbO3 Based Borate Glass System.

    Science.gov (United States)

    Kruea-In, Chatchai; Intawin, Pratthana; Leenakul, Wilaiwan

    2015-11-01

    The incorporation method was employed to produce ferroelectric glass ceramics from the K2O-Nb2O5-B2O3 glass system. The nanocrystalline potassium niobate (KNbO3) was first prepared using a simple mixed oxide method, where the B2O3 was initially mixed and then melted to form glass. The successfully produced optically transparent glass was then subjected to a heat treatment schedule for further crystallization at temperatures ranging from 500 to 650 degrees C, which resulted in the precipitation of the KNbO3 phase, together with the K3B2Nb3O12 phase. Scanning electron microscopy (SEM) showed the presence of randomly oriented KNbO3 crystals dispersed in a continuous glass matrix. It was found that the glass ceramics subjected to the heat treatment at temperatures higher than 545 degrees C were opaque, while the lower gave a highly transparent glass ceramics. The crystal size and crystallinity were found to increase with increasing heat treatment temperature, which in turn plays an important role in controlling the properties of the glass ceramics, including physical, optical, and dielectric properties.

  11. Effect of cement kiln dust and gamma irradiation on the ultrasonic parameters of HMO borate glasses

    Science.gov (United States)

    Abd elfadeel, G.; Saddeek, Yasser B.; Mohamed, Gehan Y.; Mostafa, A. M. A.; Shokry Hassan, H.

    2017-03-01

    Glass samples with the chemical formula x CKD-(100 - x) (5Na2O-65 B2O3-9 Bi2O3-21PbO), (0 ⩽ x ⩽ 32 mol%) were prepared. The density and the ultrasonic estimations of the investigated glasses were analyzed at room temperature before and after the impact of two dosages of gamma irradiation to study the effect of both CKD and gamma radiation. It was found that the density, and the ultrasonic parameters are sensitive to the variety of the content of CKD and the effect of γ-radiation. Replacement of oxides with higher atomic weights such as Bi2O3 and PbO by CKD decreases the density. Analysis of the behavior of the ultrasonic parameters demonstrates that creation of CaO6 and SiO4 on one hand and an alternate transformation between BO4 and BO3 structural units, on the other hand, affect the increase of the ultrasonic velocities and the elastic moduli. Moreover, the density and the ultrasonic parameters decrease somewhat with the increase of the doses of γ-irradiation. The variations of the previous physical parameters can be referred to the creation of radiation imperfections, which occupied the voids inside the glass structure.

  12. Composition dependent spectroscopic properties of Nd{sup 3+} doped sodium lead borate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Mohan, Shaweta, E-mail: shwetamohan-82@yahoo.co.in [BBK DAV College for Women, Amritsar-143001, Punjab (India); Thind, Kulwant Singh [Guru Nanak Dev University, Amritsar-143001, Punjab (India)

    2016-05-23

    Nd{sup 3+} doped oxide glasses of the type xNa{sub 2}O–30 PbO–(69.5-x) B{sub 2}O{sub 3}–0.5Nd{sub 2}O{sub 3} were prepared and investigated for physical and spectroscopic properties. Optical absorption spectra and Judd-Ofelt theory has been used to determine the oscillator strengths and the intensity parameters Ω{sub λ} (λ=2, 4, 6). The radiative transition probability (A), radiative lifetime (τ{sub R}) and branching ratio (β{sub R}) for the fluorescent levels of Nd{sup 3+} in the prepared glasses have been determined. The lasing efficiency of the prepared glasses has been characterized by the spectroscopic quality factor (Ω{sub 4} / Ω{sub 6}), the value of which is in the range 0.2-1.5, typical for Nd{sup 3+} in different laser hosts. The radiative transition probability of the potential lasing transition {sup 4}F{sub 3/2} → {sup 4}I{sub 11/2} of Nd{sup 3+} ions is found to increase with increase in content of Na{sub 2}O.

  13. Effect of Nd2O3 addition on structure and characterization of lead bismuth borate glass

    Directory of Open Access Journals (Sweden)

    I. Kashif

    2014-01-01

    Full Text Available The effect of different contents of Nd2O3 on the thermal transition temperature, density and structure of 25 Bi2O3 – 25 PbO – 50 B2O3 has been investigated using X-ray diffraction (XRD, differential thermal analysis (DTA, infrared spectrophotometer (FTIR and optical absorption. The amorphous phase has been identified based on X-ray diffraction analysis. The neodymium oxide plays the role as a glass-modifier and influences on BO3 ↔ BO4 conversion. The observed increase in Tg with Nd2O3 reflects an increase in bond strength. The decrease of the density and the increase of the molar volume with the addition of Nd2O3 contents attributed to an increase in the number of Non-bridging oxygen (NBOS. The optical absorption results are indicating the higher covalency of the Nd–O bond for glass containing 2 mol% of Nd2O3. In addition, a lowest covalency is observed in glass with 1 mol% Nd2O3. In addition, it is considered necessary in the construction of compact and efficient laser source.

  14. Structural investigation and electron paramagnetic resonance of vanadyl doped alkali niobium borate glasses.

    Science.gov (United States)

    Agarwal, A; Sheoran, A; Sanghi, S; Bhatnagar, V; Gupta, S K; Arora, M

    2010-03-01

    Glasses with compositions xNb(2)O(5).(30-x)M(2)O.69B(2)O(3) (where M=Li, Na, K; x=0, 4, 8 mol%) doped with 1 mol% V(2)O(5) have been prepared using normal melt quench technique. The IR transmission spectra of the glasses have been studied over the range 400-4000 cm(-1). The changes caused by the addition of Nb(2)O(5) on the structure of these glasses have been reported. The electron paramagnetic resonance spectra of VO(2+) ions in these glasses have been recorded in X-band (9.14 GHz) at room temperature (300 K). The spin Hamiltonian parameters, dipolar hyperfine coupling parameter and Fermi contact interaction parameter have been calculated. It is observed that the resultant resonance spectra contain hyperfine structures (hfs) due to V(4+) ions which exist as VO(2+) ions in octahedral coordination with a tetragonal compression in the present glasses. The tetragonality of V(4+)O(6) complex decreases with increasing concentration of Nb(2)O(5). The 3d(xy) orbit contracts with increase in Nb(2)O(5):M(2)O ratio. Values of the theoretical optical basicity, Lambda(th), have also been reported. Copyright 2009 Elsevier B.V. All rights reserved.

  15. Electron paramagnetic resonance spectra of copper ion doped lithium barium borate glasses

    Science.gov (United States)

    Bhogi, Ashok; Kumar, R. Vijaya; Kistaiah, P.

    2017-05-01

    Glasses with composition 25Li2O-15BaO- (60-x) B2O3- x CuO (where x=0, 0.2, 0.4, 0.6, 0.8 and 1.0 mol %) were prepared by the conventional melt quenching technique. These glasses were characterized using X-ray diffraction (XRD). Electron paramagnetic resonance spectra of prepared glasses have been studied. The EPR spectrum consists of four hyperfine lines characteristic of Cu2+ ions. From the observed spectra the spin-Hamiltonian parameters have been evaluated. The values of spin-Hamiltonian parameters indicate that the Cu2+ ions in the studied glasses were present in octahedral coordination with a strong tetragonal distortion. The molecular orbital coefficients have been evaluated.

  16. Temperature dependent electrical transport characteristics of BaTiO3 modified lithium borate glasses

    Directory of Open Access Journals (Sweden)

    Vanita Thakur

    2015-08-01

    Full Text Available The glass samples with composition (70B2O3-29Li2O-1Dy2O3-xBT; x = 0, 10 and 20 weight percent, have been prepared by conventional melt quench technique. The dielectric measurements as a function of temperature have been carried out on these samples in the frequency range 1 Hz-10 MHz. The dielectric relaxation characteristics of these samples have been studied by analyzing dielectric spectroscopy, dielectric loss, electric modulus formulation and electrical conductivity spectroscopy. It is found that the dielectric permittivity of the samples increases with an increase in the temperature and BT content. The frequency dependent ac conductivity has been analyzed using Jonscher’s universal power law whereas non exponential KWW function has been invoked to fit the experimental data of the imaginary part of the electric modulus. The values of the activation energy determined from the electric modulus and that from dc conductivity have been found to be quite close to each other suggesting that the same type of charge barriers are involved in the relaxation and the conduction mechanisms. The stretched exponent (β and the power exponent (n have been found to be temperature and composition dependent. The decrease in n with an increase in temperature further suggested that the ac conduction mechanism of the studied samples follows the correlated barrier hopping (CBH model.

  17. Electron Spin Resonance and optical absorption spectroscopic studies of manganese centers in aluminium lead borate glasses.

    Science.gov (United States)

    SivaRamaiah, G; LakshmanaRao, J

    2012-12-01

    Electron Spin Resonance (ESR) and optical absorption studies of 5Al(2)O(3)+75H(3)BO(3)+(20-x)PbO+xMnSO(4) (where x=0.5, 1,1.5 and 2 mol% of MnSO(4)) glasses at room temperature have been studied. The ESR spectrum of all the glasses exhibits resonance signals with effective isotropic g values at ≈2.0, 3.3 and 4.3. The ESR resonance signal at isotropic g≈2.0 has been attributed to Mn(2+) centers in an octahedral symmetry. The ESR resonance signals at isotropic g≈3.3 and 4.3 have been attributed to the rhombic symmetry of the Mn(2+) ions. The zero-field splitting parameter (zfs) has been calculated from the intensities of the allowed hyperfine lines. The optical absorption spectrum exhibits an intense band in the visible region and it has been attributed to (5)E(g)→(5)T(2g) transition of Mn(3+)centers in an octahedral environment. The optical band gap and the Urbach energies have been calculated from the ultraviolet absorption edges. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. Potential dependence of surface crystal structure of iron passive films in borate buffer solution

    International Nuclear Information System (INIS)

    Deng, Huihua; Nanjo, Hiroshi; Qian, Pu; Santosa, Arifin; Ishikawa, Ikuo; Kurata, Yoshiaki

    2007-01-01

    The effect of passivation potential on surface crystal structure, apparent thickness and passivity of oxide films formed on pure iron prepared by plasma sputter deposition was investigated. The crystallinity was improved with passivation potential and the width of atomically flat terraces was expanded to 6 nm when passivating at 750 mV for 15 min, as observed by ex situ scanning tunneling microscopy (STM) after aging in air (<30% RH). Apparent thickness and passivity are linearly dependent on passivation potential. The former weakly depends on passivation duration, the latter strongly depends on passivation duration. This is well explained by the correlation between crystal structure and passivity

  19. Cationic aluminum hydride complexes: reactions of carbene-alane adducts with trityl-borate.

    Science.gov (United States)

    Cao, Levy L; Daley, Erika; Johnstone, Timothy C; Stephan, Douglas W

    2016-04-18

    Reaction of (Idipp)AlH3 with [Ph3C][B(C6F5)4] in toluene affords the dimeric aluminum dication [((Idipp)AlH(μ-H))2][B(C6F5)4]22. In contrast, the reaction of (IBn)AlH3 with [Ph3C][B(C6F5)4] in bromobenzene gives a redistribution product, the salt of a monomeric dication [(IBn)2AlH][B(C6F5)4]24.

  20. Effect of irradiation on differential thermal properties and crystallization behavior of some lithium borate glasses

    International Nuclear Information System (INIS)

    El-Alaily, N.A.; Mohamed, R.M.

    2001-01-01

    Differential thermal properties and the crystallization behavior of binary system Li 2 O-B 2 O 3 glasses were investigated. The effects of the presence of oxides of aluminum, lead or one of the transition metals TiO 2 or V 2 O 5 or Fe 2 O 3 in the parent glass were also studied. The effects of three different heat treatments on the crystalline structure of all the studied glasses were also investigated. The results showed that all glass samples were amorphous before the heat treatment, with the most common formed phase being tetraborate Li 2 B 8 O 13 (Li 2 O-4B 2 O 3 ). The exposure of the glass samples to either gamma rays or fast neutrons resulted in considerable changes in their thermal behavior. The results also showed that T g increases for all studied glasses when subjected to irradiation either by fast neutron or gamma rays, while T c decreased only at higher doses