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Sample records for 2-aminoethoxydiphenyl borate 2-apb

  1. A Novel Strategy for TNF-Alpha Production by 2-APB Induced Downregulated SOCE and Upregulated HSP70 in O. tsutsugamushi-Infected Human Macrophages

    Liang, Jui-Lin; Tsai, Ming-Hsien; Yen, Chia-Jung; Li, Hsiu-Wen; Chiu, Siou-Jin; Chang, Chung-Hsing; Huang, Yaw-Bin; Lin, Ming-Wei; Yoshioka, Tohru

    2016-01-01

    Orientia (O.) tsutsugamushi-induced scrub typhus is endemic across many regions of Asia and the Western Pacific, where an estimated 1 million cases occur each year; the majority of patients infected with O. tsutsugamushi end up with a cytokine storm from a severe inflammatory response. Previous reports have indicated that blocking tumor necrosis factor (TNF)-α reduced cell injury from a cytokine storm. Since TNF-α production is known to be associated with intracellular Ca2+ elevation, we examined the effect of store-operated Ca2+ entry (SOCE) inhibitors on TNF-α production in O. tsutsugamushi-infected macrophages. We found that 2-aminoethoxydiphenyl borate (2-APB), but not SKF96365, facilitates the suppression of Ca2+ mobilization via the interruption of Orai1 expression in O. tsutsugamushi-infected macrophages. Due to the decrease of Ca2+ elevation, the expression of TNF-α and its release from macrophages was repressed by 2-APB. In addition, a novel role of 2-APB was found in macrophages that causes the upregulation of heat shock protein 70 (HSP70) expression associated with ERK activation; upregulated TNF-α production in the case of knockdown HSP70 was inhibited with 2-APB treatment. Furthermore, elevated HSP70 formation unexpectedly did not help the cell survival of O. tsutsugamushi-infected macrophages. In conclusion, the parallelism between downregulated Ca2+ mobilization via SOCE and upregulated HSP70 after treatment with 2-APB against TNF-α production was found to efficiently attenuate an O. tsutsugamushi-induced severe inflammatory response. PMID:27472555

  2. TRPV3 channels mediate Ca²⁺ influx induced by 2-APB in mouse eggs.

    Lee, Hoi Chang; Yoon, Sook-Young; Lykke-Hartmann, Karin; Fissore, Rafael A; Carvacho, Ingrid

    2016-01-01

    Fertilization in mammals is initiated when a sperm fuses with a mature MII oocyte, also known as egg, and triggers a plethora of finely controlled processes identified as egg activation. The completion of all events of egg activation is driven by and depends on a series of repetitive calcium (Ca(2+)) increases (Ca(2+) oscillations), which rely on Ca(2+) influx from the extracellular media. Ca(2+) channels on the egg plasma membrane (PM) are thought to mediate this influx. The TRP Ca(2+) channel TRPV3 is differentially expressed during oocyte maturation, being most active at the MII stage. Specific stimulation of TRPV3 channels promotes Ca(2+) influx sufficient to induce egg activation and parthenogenesis. Here, we explore the function and distribution dynamics of the TRPV3 channel protein during maturation. Using dsRNA, TrpV3 overexpression, and inhibitors of protein synthesis, we modified the expression levels of the channel and showed that the TRPV3 protein is synthesized and translocated to the PM during maturation. We demonstrated that 2-APB at the concentrations used here to promote Ca(2+) influx in eggs, specifically and reversibly targets TRPV3 channels without blocking IP3R1. Finally, we found that the activity of TRPV3 channels is dependent upon an intact actin cytoskeleton, suggesting an actin-based regulation of its expression and/or function on the PM. Collectively, our results show TRPV3 is a target of 2-APB in eggs, a condition that can be used to induce parthenogenesis. The need of an intact actin cytoskeleton for the function of TRPV3 channels in oocytes is a novel finding and suggests the rearrangements of actin that occur during maturation could regulate both the presence on the PM and/or the function of TRPV3 and of other Ca(2+) channels involved in oocyte maturation and fertilization. PMID:26725171

  3. The gap junction inhibitor 2-aminoethoxy-diphenyl-borate protects against acetaminophen hepatotoxicity by inhibiting cytochrome P450 enzymes and c-jun N-terminal kinase activation

    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

  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

    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. Effects of 2-APB on Store-operated Ca2+ Channel Currents of Hepatocytes after Hepatic Ischemia/Reperfusion Injury in Rats

    HUANG Changzhou; ZHANG Zongming; QIU Fazu

    2005-01-01

    The effects of hepatic ischemia/reperfusion (I/R) injuries on hepatocellular viability and store-operated calcium current (Isoc) in isolated rat hepatocytes and the effects of 2-APB on storeoperated calcium current (Isoc) in isolated rat hepatocytes after hepaticischemia/reperfusion injuries were studied. Hepatic ischemia and reperfusion injury model was established and whole cell patch-clamp techniques were used to investigate the effects of 2-APB on Isoc. The results showed that ischemia/reperfusion injuries could significantly reduce hepatocellular viability and further increase Isoc in hepatocytes and 2-APB (20, 40, 60, 80, 100 μmol/L) produced a concentration-dependent decrease of Isoc with IC50 value of 64.63±10.56 μmol/L (n= 8). It was concluded that ischemia/reperfusion injuries could reduce hepatocellular viability, probably through increased Isoc in hepatocytes and 2-APB had a protective effect on ischemia/reperfusion-induced liver injury, probably though inhibiting Isoc.

  6. Broad-range TRP channel inhibitors (2-APB, flufenamic acid, SKF-96365) affect differently contraction of resistance and conduit femoral arteries of rat

    Bencze, Michal; Behuliak, Michal; Vavřínová, Anna; Zicha, Josef

    2015-01-01

    Roč. 765, Oct 15 (2015), s. 533-540. ISSN 0014-2999 R&D Projects: GA ČR(CZ) GAP304/12/0259 Institutional support: RVO:67985823 Keywords : femoral artery * TRP channel * 2-APB * flufenamic acid * SKF-96365 * vascular contraction Subject RIV: FA - Cardiovascular Diseases incl. Cardiotharic Surgery Impact factor: 2.532, year: 2014

  7. Borat vihastas ka rumeenlasi

    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

  8. Analysis of zinc borates

    Methods for analyzing zinc borates: B2O3 determination in the presence of zinc ions and determination of zinc in the presence of borates are developed. Distributing effect of zinc in alcalometrical determination of B2O3 is removed using either its binding cationite KU-2 in H-form in hydrochloric acid medium or using complexone 3 masking. In the first case the results are underestimated, in the second one - are overestimated. When analyzing Zn the complexonometrical titration with sodium teraborate is carried out. Borate ions don't affect the accuracy of determination. Zinc borate samples of 0.1-0.15 g in dimesion are recommended according to the method suggested

  9. Photon Interaction Parameters for Some Borate Glasses

    Mann, Nisha; Kaur, Updesh; Singh, Tejbir; Sharma, J. K.; Singh, Parjit S.

    2010-11-01

    Some photon interaction parameters of dosimetric interest such as mass attenuation coefficients, effective atomic number, electron density and KERMA relative to air have been computed in the wide energy range from 1 keV to 100 GeV for some borate glasses viz. barium-lead borate, bismuth-borate, calcium-strontium borate, lead borate and zinc-borate glass. It has been observed that lead borate glass and barium-lead borate glass have maximum values of mass attenuation coefficient, effective atomic number and KERMA relative to air. Hence, these borate glasses are suitable as gamma ray shielding material, packing of radioactive sources etc.

  10. Photon Interaction Parameters for Some Borate Glasses

    Some photon interaction parameters of dosimetric interest such as mass attenuation coefficients, effective atomic number, electron density and KERMA relative to air have been computed in the wide energy range from 1 keV to 100 GeV for some borate glasses viz. barium-lead borate, bismuth-borate, calcium-strontium borate, lead borate and zinc-borate glass. It has been observed that lead borate glass and barium-lead borate glass have maximum values of mass attenuation coefficient, effective atomic number and KERMA relative to air. Hence, these borate glasses are suitable as gamma ray shielding material, packing of radioactive sources etc.

  11. Copper doped borate dosimeters revisited

    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

  12. Copper doped borate dosimeters revisited

    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

  13. Identification of TRPM7 channels in human intestinal interstitial cells of Cajal

    Byung Joo Kim; Kyu Joo Park; Hyung Woo Kim; Seok Choi; Jae Yeoul Jun; In Youb Chang; Ju-Hong Jeon; Insuk So; Seon Jeong Kim

    2009-01-01

    AIM: To investigate the characteristics of slow electrical waves and the presence of transient receptor potential melastatin-type 7 (TRPM7) in the human gastrointestinal (GI) tract. METHODS: Conventional microelectrode techniques were used to record intracellular electrical responses from human GI smooth muscle tissue. Immunohistochemistry was used to identify TRPM7 channels in interstitial cells of Cajal (ICCs). RESULTS: The human GI tract generated slow electrical waves and had ICCs which functioned as pacemaker cells. Flufenamic acid, a nonselective cation channel blocker, and 2-APB (2-aminoethoxydiphenyl borate) and La3~+, TRPM7 channel blockers, inhibited the slow waves. Also, TRPM7 channels were expressed in ICCs in human tissue. CONCLUSION: These results suggest that the human GI tract generates slow waves and that TRPM7 channels expressed in the ICCs may be involved in the generation of the slow waves.

  14. "Borat" kogus tubli hulga vaatajaid

    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)

  15. FTIR spectroscopy of borate crystals

    Kovacs, Laszlo; Beregi, E.; Polgar, K.; Peter, A.

    1999-03-01

    Infrared absorption spectroscopy has been used to study the vibrational modes in various borate crystals, the electronic transitions of Nd3+ ions in NYAB, and the stretching vibration of hydroxyl ions in CLBO crystals.

  16. Borate Minerals and RNA Stability

    Ernesto Di Mauro

    2010-08-01

    Full Text Available The abiotic origin of genetic polymers faces two major problems: a prebiotically plausible polymerization mechanism and the maintenance of their polymerized state outside a cellular environment. The stabilizing action of borate on ribose having been reported, we have explored the possibility that borate minerals stabilize RNA. We observe that borate itself does not stabilize RNA. The analysis of a large panel of minerals tested in various physical-chemical conditions shows that in general no protection on RNA backbone is exerted, with the interesting exception of ludwigite (Mg2Fe3+BO5. Stability is a fundamental property of nucleic polymers and borate is an abundant component of the planet, hence the prebiotic interest of this analysis.

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

    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"

  18. Kes on Borat? / Timo Diener

    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

  19. The Synthesis and Physical Properties of Magnesium Borate Mineral of Admontite Synthesized from Sodium Borates

    2014-01-01

    Magnesium borates are significant compounds due to their advanced mechanical and thermal durability properties. This group of minerals can be used in ceramic industry, in detergent industry, and as neutron shielding material, phosphor of thermoluminescence by dint of their extraordinary specialties. In the present study, the synthesis of magnesium borate via hydrothermal method from sodium borates and physical properties of synthesized magnesium borate minerals were investigated. The characte...

  20. Intracellular Ca2+ stores modulate SOCCs and NMDA receptors via tyrosine kinases in rat hippocampal neurons.

    Koss, David J; Riedel, Gernot; Platt, Bettina

    2009-07-01

    The regulation of intracellular Ca(2+) signalling by phosphorylation processes remains poorly defined, particularly with regards to tyrosine phosphorylation. Evidence from non-excitable cells implicates tyrosine phosphorylation in the activation of so-called store-operated Ca(2+) channels (SOCCs), but their involvement in neuronal Ca(2+) signalling is still elusive. In the present study, we determined the role of protein tyrosine kinases (PTKs) and tyrosine phosphatases (PTPs) in the coupling between intracellular Ca(2+) stores and SOCCs in neonatal rat hippocampal neurons by Fura-2 Ca(2+) imaging. An early Ca(2+) response from intracellular stores was triggered with thapsigargin, and followed by a secondary plasma membrane Ca(2+) response. This phase was blocked by the non-specific Ca(2+) channel blocker NiCl and the SOCC blocker, 2-aminoethoxydiphenyl borate (2-APB). Interestingly, two structurally distinct PTK inhibitors, genistein and AG126, also inhibited this secondary response. Application of the PTP inhibitor sodium orthovanadate (OV) also activated a sustained and tyrosine kinase dependent Ca(2+) response, blocked by NiCl and 2-APB. In addition, OV resulted in a Ca(2+) store dependent enhancement of NMDA responses, corresponding to, and occluding the signalling pathway for group I metabotropic glutamate receptors (mGluRs). This study provides first evidence for tyrosine based phospho-regulation of SOCCs and NMDA signalling in neurons. PMID:19423160

  1. Repliik filmi "Borat" kohta / Urve Kirss

    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

  2. Tribological performance of nanometer samarium borate

    2001-01-01

    Nanometer crystal samarium borate with a particle size of 20~40 nm was prepared using replacing solvent drying technique. The wear resistance and load-carrying capacity of 500SN base oil could be improved and the friction coefficient could be decreased by the addition of nanometer samarium borate. But the dosage of samarium borate nanoparticles had to be controlled at a relatively low level, a higher concentration of nanoparticles was not of beneficial to the tribological performance of the oil. The optimal dosage of nanometer samarium borate is 1.0%. Tribochemical reactions took place in the tribological process, which resulted in the formation of deposition products including diboron trioxide and disamarium trioxide. Fe2B and FeB were also found on the wear scar. The improvement of tribological properties of the oil comes from the formation of deposition layer and permeating layer.

  3. Lithium borate solid TL detectors

    A new procedure for the preparation of Li2B4O7:Cu,In and Li2B4O7:Cu,In,Ag in form of sintered pellets has been developed recently at the Institute of Nuclear Sciences Vinca, Belgrade. Very few TL materials are tissue equivalent with an effective atomic number which is very close to that of soft biological tissue (7.4). Li2B4O7 based TL dosemeters appeared to be among the most attractive, with an effective atomic number of 7.3. The thermoluminescence properties of lithium borate in form of sintered TLD pellets examined in this study include glow-curve shapes, TL sensitivity, photon dose response, minimum detectable dose, relative photon energy response, fading, reproducibility, uniformity, recommended annealing procedure and kinetic parameters. (author)

  4. Recent progress in actinide borate chemistry.

    Wang, Shuao; Alekseev, Evgeny V; Depmeier, Wulf; Albrecht-Schmitt, Thomas E

    2011-10-21

    The use of molten boric acid as a reactive flux for synthesizing actinide borates has been developed in the past two years providing access to a remarkable array of exotic materials with both unusual structures and unprecedented properties. [ThB(5)O(6)(OH)(6)][BO(OH)(2)]·2.5H(2)O possesses a cationic supertetrahedral structure and displays remarkable anion exchange properties with high selectivity for TcO(4)(-). Uranyl borates form noncentrosymmetric structures with extraordinarily rich topological relationships. Neptunium borates are often mixed-valent and yield rare examples of compounds with one metal in three different oxidation states. Plutonium borates display new coordination chemistry for trivalent actinides. Finally, americium borates show a dramatic departure from plutonium borates, and there are scant examples of families of actinides compounds that extend past plutonium to examine the bonding of later actinides. There are several grand challenges that this work addresses. The foremost of these challenges is the development of structure-property relationships in transuranium materials. A deep understanding of the materials chemistry of actinides will likely lead to the development of advanced waste forms for radionuclides present in nuclear waste that prevent their transport in the environment. This work may have also uncovered the solubility-limiting phases of actinides in some repositories, and allows for measurements on the stability of these materials. PMID:21915396

  5. ENVIRONMENTALLY FRIENDLY BORATE-BASED WOOD PRESERVATIVE - PHASE I

    This natural organic retention project proposes using lignin from emerging biorefineries to allow borates to be used as wood preservatives for exterior applications exposed to rain. Enhancing the retention of environmentally friendly borates has been the “holy grail...

  6. Synthetic Investigations in Borates, Borate Germanates, Gallium Oxonitrides, and Intermetallic Phases at Extreme Conditions

    Heymann, Gunter

    2007-01-01

    Multianvil Hochdruck-/Hochtemperatur Untersuchungen an Seltenerd Boraten, Borat Germanaten, Gallium Oxonitriden und Intermetallischen Phasen. Im Speziellen werden die neuen Borate alpha-Nd2B4O9, beta-Nd(BO2)3, delta-La,Ce(BO2)3 und Pr4B10O21 vorgestellt. Die Erweiterung des Systems durch Germanium führte zum neuen Borat Germanat Ce6(BO4)2Ge9O22. Im Bereich der Gallium Oxonitride konnte eine Spinell-Phase realisiert werden. Hochdruck-/Hochtemperatur Untersuchungen zeigten Phasenumwandlungen vo...

  7. Green colorants based on energetic azole borates.

    Glück, Johann; Klapötke, Thomas M; Rusan, Magdalena; Stierstorfer, Jörg

    2014-11-24

    The investigation of green-burning boron-based compounds as colorants in pyrotechnic formulations as alternative for barium nitrate, which is a hazard to health and to the environment, is reported. Metal-free and nitrogen-rich dihydrobis(5-aminotetrazolyl)borate salts and dihydrobis(1,3,4-triazolyl)borate salts have been synthesized and characterized by NMR spectroscopy, elemental analysis, mass spectrometry, and vibrational spectroscopy. Their thermal and energetic properties have been determined as well. Several pyrotechnic compositions using selected azolyl borate salts as green colorants were investigated. Formulations with ammonium dinitramide and ammonium nitrate as oxidizers and boron and magnesium as fuels were tested. The burn time, dominant wavelength, spectral purity, luminous intensity, and luminous efficiency as well as the thermal and energetic properties of these compositions were measured. PMID:25284439

  8. Spectroscopic Evaluation of DNA-Borate Interactions.

    Ozdemir, Ayse; Sarioglu, Omer Faruk; Tekinay, Turgay

    2015-12-01

    We describe the binding characteristics of two natural borates (colemanite and ulexite) to calf thymus DNA by UV-vis absorbance spectroscopy, circular dichroism (CD) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, and a competitive DNA binding assay. Our results suggest that colemanite and ulexite interact with calf thymus DNA under a non-intercalative mode of binding and do not alter the secondary structure of the DNA helix. The FT-IR spectroscopy results indicate that the two borates might interact with DNA through sugar-phosphate backbone binding. PMID:25994227

  9. Recent progress in actinide borate chemistry

    Wang, S.; Alekseev, E .V.; Depmeier, W.; Albrecht-Schmitt, T.E.

    2011-01-01

    The use of molten boric acid as a reactive flux for synthesizing actinide borates has been developed in the past two years providing access to a remarkable array of exotic materials with both unusual structures and unprecedented properties. [ThB(5)O(6)(OH)(6)][BO(OH)(2)]·2.5H(2)O possesses a cationic supertetrahedral structure and displays remarkable anion exchange properties with high selectivity for TcO(4)(-). Uranyl borates form noncentrosymmetric structures with extraordinarily rich topol...

  10. A crystal-chemical classification of borate structures with emphasis on hydrated borates

    Christ, C.L.; Clark, J.R.

    1977-01-01

    The rules governing formation of hydrated borate polyanions that were proposed by C.L. Christ in 1960 are critically reviewed and new rules added on the basis of recent crystal structure determinations. Principles and classifications previously published by others are also critically reviewed briefly. The fundamental building blocks from which borate polyanions can be constructed are defined on the basis of the number n of boron atoms, and the fully hydrated polyanions are illustrated. Known structures are grouped accordingly, and a shorthand notation using n and symbols ?? = triangle, T = tetrahedron is introduced so that the polyanions can be easily characterized. For example, 3:??+2T describes [B3O3(OH)5]2-. Correct structural formulas are assigned borates with known structures whereas borates of unknown structure are grouped separately. ?? 1977 Springer-Verlag.

  11. Structure and Properties of Compressed Borate Glasses

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

    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...

  12. Structural properties of Zinc Lithium borate glass

    Saidu, A.; Wagiran, H.; Saeed, M. A.; Alajerami, Y. S. M.

    2014-09-01

    Zinc Lithium Borate glasses of different composition were prepared with the aim of using it for thermoluminescence dosimetry. Melt quenching method was adopted in this process. Fourier transform Infrared (FTIR) spectroscopy and UV-vis-NIR spectroscopy techniques were employed to investigate the infrared spectra and energy band gap of different composition of Zinc Lithium Borate glasses. X-ray diffraction analysis was used to confirm the amorphous nature of the glass samples. Glass forming ability and stability of the glass was checked using Differential thermal analysis (DTA). Density, molar volume, refractive index parameters have been analyzed in the light of different concentration of the modifier. The active vibrational modes of 1200-1600 cm-1 for B-O stretching of BO3 units, 800-1200 cm-1 for B-O stretching of BO4 units and 400-800 cm-1 for bending vibration of various borate segments were detected. Addition of ZnO to lithium borate shows its influence in converting the dominant BO3 group to BO4 group. BO4 are known for creating complex defects, a situation that established deep and stable traps good for thermoluminescence phenomena. From optical data, direct and indirect energy band gap has been calculated using the data obtained from UV-vis-NIR spectroscopy. Both direct and indirect band gaps decrease with the increase of modifier Li2CO3.

  13. Magnesium Borate Synthesis by Microwave Energy: A New Method

    Azmi Seyhun Kipcak; Emek Moroydor Derun; Sabriye Piskin

    2013-01-01

    Magnesium borates are one of the major groups of boron minerals that have important properties such as high heat and corrosion resistances and high coefficients of elasticity. In this study, magnesium borate minerals are synthesized using boric acid and magnesium oxide with a new method of microwave, and the synthesized minerals are characterized by various analysis techniques. The results show that pure, “magnesium borate hydrate” minerals are obtained at the end of various steps. The charac...

  14. Characterization and Exergy Analysis of Triphenyl Borate

    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)

  15. Hydrogen-ion sputtering of borated graphite

    The development and choice of material for the first wall and other energy-stressed parts of the discharge chamber are an important aspect of fusion reactor construction. In particular, carbon-graphite materials are proposed for making limiters and protective shields of the first wall and receiving plates of diverter devices. Sputtering under ion bombardment is one of the main mechanisms of material erosion; in addition, in the case of carbon-graphite materials chemical sputtering also occurs as a result of the formation of highly volatile hydrocarbon compounds during the reaction with ions of hydrogen isotopes. Sputtering MPG carbon-graphite materials and USB-15 carbon-fiber-reinforced glass ceramic has been well studied and experimental data have been obtained on the coefficients of physical and chemical sputtering. It has been determined that hydrogen-ion sputtering of USB-15 in the range from room temperature to 1070 K is less than that of MPG-8 graphite a factor of 2-10. Bulk doping of graphite with boron substantially reduces chemical sputtering. Since processes in the surface layers are crucially important in sputtering, the possibility of reducing chemical sputtering by surface boration of carbon-graphite materials has been explored. The objective of this work was to continue the experimental investigation to determine the physical processes of sputtering of surface-borated graphite under hydrogen-ion bombardment in the temperature range corresponding to maximum chemical sputtering. Surface boration of MPG-8 and USB-15 samples was carried out by vapor-phase isothermal deposition mediated by gaseous iodine at 1223 K for 4 h (the sample was placed in a pure boron stock). The mass transfer during the vapor-phase deposition is based on the difference of the chemical potentials of iodine and carbon under isothermal conditions. The samples of the initial and borated carbon-graphite materials irradiated with a poly-energetic beam of hydrogen ions

  16. Control of optical active borates nanocrystals agglomeration

    I. Cieślik; R. Węgłowski; J. Żmija; K. Kurzydłowski; M. Płocińska; M. Oćwieja

    2013-01-01

    Purpose: The purposes of this study explore the possibility of total control the agglomeration of nanoborates powders. The great potential of PDLCs can be enhanced by using dye-doped or nanoparticles-doped materials, such as borates [1]. It is important to know how to prepare nanoparticles in order to obtain a high level of dispersion in the composites. Otherwise, even small an agglomeration does not give a possibility on the appropriate characteristic of properties and interp...

  17. Coarsening kinetics in demixed lead borate melts.

    Dittmar, A; Bornhöft, H; Deubener, J

    2013-06-14

    Lead borate melts have been demixed at temperatures in range from 723 to 773 K for times up to 20 h. It is found that increasing time and temperature lead to characteristic changes in the size distribution of boron trioxide drops in the lead-rich glassy matrix (cube root time dependence of diffusion controlled coarsening. The diffusivity of the coarsening process was determined using liquid-liquid interfacial energy associated with drop deformation in glass specimens subjected to uniaxial compression. Diffusion coefficients of coarsening were found to match with those of (207)Pb and (18)O tracer ions in the lead borate system but differ up to four orders of magnitude from the Eyring diffusivity and by a factor of ≈7 from the activation energy of viscous flow. The results indicate that coarsening in demixed lead borate melts is most likely controlled by the short range dynamics of the interaction between lead cations and BO4 units, which are decoupled from the time scales of cooperative rearrangements of the glassy network at T < 1.1 Tg. PMID:23781800

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

    2014-01-01

    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, whic...

  19. Corrosion behaviour of borated aluminium used as neutron absorber

    The electrochemical behaviour of pure and borated aluminium was examined. Measurements were performed in two different electrolytes at 90 C containing different trace-amounts of chloride. For borated aluminium current transients, i.e. metastable depassivation events were found. It is suggested to attribute these transients to less stable passivation layers in comparison to pure aluminium

  20. Tyrosine phosphorylation modulates store-operated calcium entry in cultured rat epididymal basal cells.

    Zuo, Wu-Lin; Du, Jian-Yang; Huang, Jie-Hong; Li, Sheng; Zhang, Geng; Chen, Si-Liang; Ruan, Ye-Chun; Cheng, Christopher H K; Zhou, Wen-Liang

    2011-04-01

    Store-operated calcium entry (SOCE) is essential for many cellular processes. In this study, we investigated modulation of SOCE by tyrosine phosphorylation in rat epididymal basal cells. The intracellular Ca(2+) ([Ca(2+)]i) measurement showed that SOCE occurred in rat epididymal basal cells by pretreating the cells with thapsigargin (Tg), the inhibitor of sarco-endoplasmic reticulum Ca(2+)-ATPase. To identify the role of Ca(2+) channels in this response, we examined the effects of transient receptor potential canonical channel blockers 2-aminoethoxydiphenyl borate (2-APB), 1-[β-[3-(4-methoxyphenyl)pro-poxy]-4-methoxyphenethyl]-1H-imidazole hydrochloride(SKF96365), Gd(3+), and non-selective cation channel blocker Ni(2+) respectively on SOCE and found that these blockers could inhibit the Ca(2+) influx to different extent. Furthermore, we studied the regulation of SOCE by tyrosine kinase pathway. The inhibitor of tyrosine kinase genistein remarkably suppressed the SOCE response, whereas sodium orthovanadate, the inhibitor of tyrosine phosphatase, greatly enhanced it. The results suggest that tyrosine kinase pathway plays a significant role in the initiation of SOCE and positively modulates SOCE in epididymal basal cells. PMID:20857412

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

    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 B2O3. The number of BO3 and BO4 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

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

    Doweidar, H. [Glass Research Group, Physics Department, Faculty of Science, Mansoura University, P.O. Box 83, Mansoura 35516 (Egypt)]. E-mail: hdoweidar@mans.edu.eg; El-Damrawi, G.M. [Glass Research Group, Physics Department, Faculty of Science, Mansoura University, P.O. Box 83, Mansoura 35516 (Egypt); Moustafa, Y.M. [Glass Research Group, Physics Department, Faculty of Science, Mansoura University, P.O. Box 83, Mansoura 35516 (Egypt); Ramadan, R.M. [Glass Research Group, Physics Department, Faculty of Science, Mansoura University, P.O. Box 83, Mansoura 35516 (Egypt)

    2005-05-15

    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{sub 2}O{sub 3}. The number of BO{sub 3} and BO{sub 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.

  3. 21 CFR 872.3400 - Karaya and sodium borate with or without acacia denture adhesive.

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Karaya and sodium borate with or without acacia... 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...

  4. Control of optical active borates nanocrystals agglomeration

    I. Cieślik

    2013-12-01

    Full Text Available Purpose: The purposes of this study explore the possibility of total control the agglomeration of nanoborates powders. The great potential of PDLCs can be enhanced by using dye-doped or nanoparticles-doped materials, such as borates [1]. It is important to know how to prepare nanoparticles in order to obtain a high level of dispersion in the composites. Otherwise, even small an agglomeration does not give a possibility on the appropriate characteristic of properties and interpretation of the results. The deagglomeration methods applied until now give the decrease of agglomeration to a lesser extent than our method. Characteristic size and shape of particles made with sol-gel process is difficult to perform. Design/methodology/approach: Nanopowders samples of YAB and LCBO were prepared with sol-gel method. Deagglomeration process was carried out using acetic acid. The morphology and size of nanopowders were investigated by scanning electron microscopy (SEM. The crystallite sizes were determinated with IPS UA method. Findings: It was confirmed that the acetic acid influence on the decrease of agglomeration. It was also determined of conditions for preparation borates nanopowders samples (concentration acetic acind time and temperature of drying prepared samples. We have proved that a reagent used for deagglomeration process does not affect the structure of the investigated nanoborates used in an experimental. Research limitations/implications: The results can be used to the prepared of nanocompades of borates to observe a morphology and reliable assessment of nanocrystalline size. Originality/value: Our study shows how to prepare a sample of particles to observe morphology and measure the size of nanograins. In our study we found excellent solution, the medium, which not influence the inorganic nanomaterial structure. Result seems to be excellent and very perspective. We have showed as that measurement type influence the results of particles size.

  5. ULTRASONIC AND HYPERSONIC BEHAVIOURS OF BORATE GLASSES

    Carini, Giovanni; Tripodo, Gaspare; Borjesson, Lars; Zanghellini, Ezio; A BARTOLOTTA

    2007-01-01

    Abstract Comparative measurements of Brillouin light scattering and ultrasounds in (K2O)0.04(B2O3)0.96 and (Ag2O)0.14(B2O3)0.86 borate glasses as a function of temperature between 1.5 and 300 K reveal that distinct mechanisms regulate the temperature behaviours of the acoustic attenuation. In the MHz range the attenuation and the sound velocity are mainly governed by (i) quantum-mechanical tunnelling below 20 K, (ii) thermally activated relaxations between 20 and 200 K and (iii) vi...

  6. [Raman and infrared spectrograms of organic borate intercalated hydrotalcite].

    Zhang, Jing-Yu; Bai, Zhi-Min; Zhao, Dong

    2013-03-01

    The pattern of X-ray diffraction, the Raman and infrared spectra of organic borate intercalated hydrotalcite were discussed. The well crystallized zinc-aluminum layered double hydroxides (Zn-Al LDHs) intercalated by carbonate ions and borate ions were respectively prepared by co-precipitation method. Patterns of X-ray diffraction showed that the (003) reflection of borate-LDHs was sharp and symmetric and shifted to lower angle than that of carbonate-LDHs. The gallery height of borate-LDHs increased from 0. 28 nm to 0.42 nm after intercalation, indicating that interlayered carbonate ions were substituted by borate anions. The Raman and IR spectra showed that specific bands of carbonate ions in the borate-LDHs disappeared, but with the presence of B3O3(OH)4- X B4O5(OH)4(2-) and B(OH)4- in the interlayer galleries. The hydroxide interlayer anions had a significant influence on the band positions in Raman and infrared spectra of modes related to the hydroxyl group. Our results indicate that single phase and pure borate-pillared LDHs can be obtained using tributyl orthoborate as intercalating agents, and the change in the structure and nature of hydrotalcite can be detected precisely by Raman spectroscopy. PMID:23705437

  7. Towards modeling gadolinium-lead-borate glasses

    Infrared spectra of gadolinium-lead-borate glasses of the xGd2O3.(100 - x)[3B2O3.PbO] system, where x = 0, 5, 10, 15, 25, 35 and 50 mol.%, have been recorded to explore the role of content of gadolinium ions behaving as glass modifier. The FTIR spectroscopy data for the xGd2O3.(1 - x)[3B2O3.PbO] glasses show the structural role of lead ions as a network-formers and of the gadolinium ions network modifiers. Adding of the rare earth ion up to 35 mol.% into the glass matrix, the IR bands characteristic to the studied glasses become sharper and more pronounced. Structural changes, as recognized by analyzing band shapes of IR spectra, revealed that Gd2O3 causes a change from the continuous borate network to the continuous lead-borate network interconnected through Pb-O-B and B-O-B bridges and the transformation of some tetrahedral [BO4] units into trigonal [BO3] units. Then, gadolinium ions have affinity towards [BO3] structural units which contain non-bridging oxygens necessary for the charge compensation because the more electronegative [BO3] structural units were implied in the formation of B-O-Gd bonds and the transformation of glass network into a glass ceramic. We propose a possible structural model of building blocks for the formation of continuous random 3B2O3.PbO network glass used by density functional theory (DFT) calculations. DFT calculations show that lead atoms occupy three different sites in the proposed model. The first is coordinated with six oxygen atoms forming distorted octahedral geometries. The second lead atom has an octahedral oxygen environment and the five longer Pb-O bonds are considered as participating in the metal coordination scheme. The third lead atom has ionic character. In agreement with the results offered by the experimental FTIR data, the theoretical IR data confirm that our proposed structure is highly possible.

  8. DVD. Borat - ühiskonna sanitar / Tiit Tuumalu

    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

  9. Borat tungib psüühesse / Rain Tolk

    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

  10. Samarium fluorescence efficiency in high mass density borate glasses

    A series of Sm3+-doped lead borate glasses with a lead oxide content varying from 20 mol% to 80 mol% is investigated. Raman spectroscopy was used to investigate the influence of the network modifier content on the glass structure, in particular, on the phonon spectrum of the different lead borate glasses. In addition to the significant changes in the glass structure, the lead doping also has a significant influence on the fluorescence properties of Sm3+ co-doped glasses. -- Highlights: ► Structural changes in lead borate glasses studied by Raman spectroscopy. ► Tunable intrinsic fluorescence in lead borate glasses. ► Energy transfer between the network modifier Pb2+ and Sm3+. ► Cut-off energy shifts with increasing PbO content

  11. 40 CFR 180.1121 - Boric acid and its salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate...

    2010-07-01

    ... (sodium borate decahydrate), disodium octaborate tetrahydrate, boric oxide (boric anhydride), sodium borate and sodium metaborate; exemptions from the requirement of a tolerance. 180.1121 Section 180.1121... salts, borax (sodium borate decahydrate), disodium octaborate tetrahydrate, boric oxide (boric...

  12. Borate Minerals and Origin of the RNA World

    Grew, Edward S.; Bada, Jeffrey L.; Hazen, Robert M.

    2011-08-01

    The RNA World is generally thought to have been an important link between purely prebiotic (>3.7 Ga) chemistry and modern DNA/protein biochemistry. One concern about the RNA World hypothesis is the geochemical stability of ribose, the sugar moiety of RNA. Prebiotic stabilization of ribose by solutions associated with borate minerals, notably colemanite, ulexite, and kernite, has been proposed as one resolution to this difficulty. However, a critical unresolved issue is whether borate minerals existed in sufficient quantities on the primitive Earth, especially in the period when prebiotic synthesis processes leading to RNA took place. Although the oldest reported colemanite and ulexite are 330 Ma, and the oldest reported kernite, 19 Ma, boron isotope data and geologic context are consistent with an evaporitic borate precursor to 2400-2100 Ma borate deposits in the Liaoning and Jilin Provinces, China, as well as to tourmaline-group minerals at 3300-3450 Ma in the Barberton belt, South Africa. The oldest boron minerals for which the age of crystallization could be determined are the metamorphic tourmaline species schorl and dravite in the Isua complex (metamorphism between ca. 3650 and ca. 3600 Ma). Whether borates such as colemanite, ulexite and kernite were present in the Hadean (>4000 Ma) at the critical juncture when prebiotic molecules such as ribose required stabilization depends on whether a granitic continental crust had yet differentiated, because in its absence we see no means for boron to be sufficiently concentrated for borates to be precipitated.

  13. ІNVESTIGATION OF PECULIARITIES OF PISTON RINGS LASER BORATING

    BOLSHAKOV V. I.

    2015-11-01

    Full Text Available Problem formulation. Piston rings are subject to wear while in operation. Insufficient wear resistance of materials limits the growth of machines productivity as well as the terms of their exploitation. The required complex of properties of piston rings made of cast iron cannot be always reached by applying traditional methods of heat treatment or chemical heat treatment processing. Thus, application of traditional borating methods associated with diffusion of boron into the solid phase leads to the formation of the working layer exhibiting high brittleness. Therefore, the problem of increasing the wear resistance of piston rings without embrittlement is challenging. The use oflaser heating during borating provides the formation of a new layer with special properties. However, the optimum properties can be achieved only after determining the relationship between the parameters of running a process and the depth of the borated layer. Goal of research. To determine the influence of laser heating parameters on the depth of the borated layer, as the properties of piston rings depend on the depth of the latter. Conclusions. Increase in the speed of displacing parts during laser heating reduces the depth of the borated layer, and increase of the spot diameter enhances the depth of the layer. The phases and structural components of the borated layer were interpreted by means of X-ray and metallographic methods. The results of investigations can be applied to other machine parts, which are subject to intensive wear.

  14. Inhibition of SOCs Attenuates Acute Lung Injury Induced by Severe Acute Pancreatitis in Rats and PMVECs Injury Induced by Lipopolysaccharide.

    Wang, Guanyu; Zhang, Jingwen; Xu, Caiming; Han, Xiao; Gao, Yanyan; Chen, Hailong

    2016-06-01

    Acute lung injury (ALI) is a critical complication of the severe acute pancreatitis (SAP), characterized by increased pulmonary permeability with high mortality. Pulmonary microvascular endothelial cells (PMVECs) injury and apoptosis play a key role in ALI. Previous studies indicated that store-operated calcium entry (SOCE) could regulate a variety of cellular processes. The present study was to investigate the effects of SOCE inhibition on ALI induced by SAP in Sprague-Dawley rats, and PMVECs injury induced by lipopolysaccharide (LPS). Rat model of SAP-associated ALI were established by the retrograde infusion of sodium deoxycholate. Serum levels of amylase, TNF-α, and IL-6, histological changes, water content of the lung, oxygenation index, and ultrastructural changes of PMVECs were examined in ALI rats with or without store-operated Ca(2+) channels (SOCs) pharmacological inhibitor (2-aminoethoxydiphenyl borate, 2-APB) pretreatment. For in vitro studies, PMVECs were transiently transfected with or without small interfering RNA (siRNA) against calcium release-activated calcium channel protein1 (Orai1) and stromal interaction molecule1 (STIM1), the two main molecular constituents of SOCs, then exposed to LPS. The viability of PMVECs was determined. The expression of STIM1, Orai1, Bax, and caspase3, both in lung tissue and in PMVECs, were assessed by quantitative real-time PCR and western blot. Administration of sodium deoxycholate upregulated the expression of SOCs proteins in lung tissue. Similarly, the SOCs proteins were increased in PMVECs induced by LPS. 2-APB reduced the serum levels of amylase, TNF-α, and IL-6, and attenuated lung water content and histological findings. In addition, the decreased oxygenation index and ultrastructural damage in PMVECs associated with SAP were ameliorated after administration of 2-APB. Knockdown of STIM1 and Orai1 inhibited LPS-induced PMVECs death. Furthermore, blockade of SOCE significantly suppressed Orai1, STIM1, Bax

  15. Borate Deposits of Turkey and Argentina; A Summary and Geological Comparison

    ALONSO, CAHİT HELVACI & RICARDO N.

    2000-01-01

    Turkey has the largest borate reserves in the world and Argentina is in third place. Both countries have calcium and sodium borate deposits where colemanite, ulexite and borax are the principal minerals. We present here a comparison of the main borate deposits interlayered in continental Miocene volcaniclastic rocks of the Anatolian plateau (Turkey) and those of the Puna high plateau (Argentina). The main borate deposits of Turkey are at Emet, Bigadiç, Kestelek and Kırka. Emet is in the w...

  16. Kinetic parameters and TL mechanism in cadmium tetra borate phosphor

    Annalakshmi, O. [Radiological Safety Division, Materials Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Jose, M.T., E-mail: mtj@igcar.gov.in [Radiological Safety Division, Materials Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Sridevi, J. [Central Leather Research Institute, Council of Scientific and Industrial Research, Chennai 600 020, Tamilnadhu (India); Venkatraman, B. [Radiological Safety Division, Materials Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Amarendra, G. [Materials Physics Division, Indira Gandhi Centre for Atomic Research, Kalpakkam-603102 (India); Mandal, A.B. [Central Leather Research Institute, Council of Scientific and Industrial Research, Chennai 600 020, Tamilnadhu (India)

    2014-03-15

    Polycrystalline powder samples of cadmium tetra borate were synthesized by a simple solid state sintering technique and gamma irradiated sample showed a simple Thermoluminescence (TL) glow peak around 460 K. The TL kinetic parameters of gamma irradiated phosphor were determined by initial rise (IR), isothermal decay (ID), peak shape (PS), variable heating rate (VHR) and glow curve de-convolution method. The kinetic parameters such as activation energy (E), frequency factor (s) and order of kinetics (b) were calculated by IR, ID, PS and VHR methods are in the order of ∼1.05 eV, 10{sup 9}–10{sup 12} s{sup −1} and 1.58, respectively. From the results of TL and PL emission studies carried out on the phosphor revealed that the defect centers related to TL is different from that for PL. EPR measurements were carried out to identify the defect centers formed in cadmium tetra borate phosphor on gamma irradiation. Based on EPR studies the mechanism for TL process in cadmium tetra borate is proposed in this paper -- Highlights: • Polycrystalline powder samples of undoped cadmium tetra borate synthesized. • Cadmium tetra borate phosphor exhibits a dosimetric peak at 458 K. • Kinetic parameters of the trap responsible for TL evaluated. • TL mechanism is proposed from TL to EPR correlation studies.

  17. Kinetic parameters and TL mechanism in cadmium tetra borate phosphor

    Polycrystalline powder samples of cadmium tetra borate were synthesized by a simple solid state sintering technique and gamma irradiated sample showed a simple Thermoluminescence (TL) glow peak around 460 K. The TL kinetic parameters of gamma irradiated phosphor were determined by initial rise (IR), isothermal decay (ID), peak shape (PS), variable heating rate (VHR) and glow curve de-convolution method. The kinetic parameters such as activation energy (E), frequency factor (s) and order of kinetics (b) were calculated by IR, ID, PS and VHR methods are in the order of ∼1.05 eV, 109–1012 s−1 and 1.58, respectively. From the results of TL and PL emission studies carried out on the phosphor revealed that the defect centers related to TL is different from that for PL. EPR measurements were carried out to identify the defect centers formed in cadmium tetra borate phosphor on gamma irradiation. Based on EPR studies the mechanism for TL process in cadmium tetra borate is proposed in this paper -- Highlights: • Polycrystalline powder samples of undoped cadmium tetra borate synthesized. • Cadmium tetra borate phosphor exhibits a dosimetric peak at 458 K. • Kinetic parameters of the trap responsible for TL evaluated. • TL mechanism is proposed from TL to EPR correlation studies

  18. 40 CFR 721.1880 - Borate(1-), tris(acetato-.kappa.O)hydro-, sodium, (T-4)-.

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Borate(1-), tris(acetato-.kappa.O... New Uses for Specific Chemical Substances § 721.1880 Borate(1-), tris(acetato-.kappa.O)hydro-, sodium... substance identified as borate(1-), tris(acetato-.kappa.O)hydro-, sodium, (T-4)- (PMN P-00-0922; CAS...

  19. 40 CFR 721.5454 - Methylium, tripohenyl-, tetrakis(pentafluorophenyl) borate (1-).

    2010-07-01

    ...(pentafluorophenyl) borate (1-). 721.5454 Section 721.5454 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.5454 Methylium, tripohenyl-, tetrakis(pentafluorophenyl) borate (1-). (a... methylium, tripohenyl-, tetrakis(pentafluorophenyl) borate (1-) (PMN P-00-0637; CAS No. 136040-19-2)...

  20. Photon-Induced Borate Groups Transformation by Femtosecond Laser

    杨晓燕; 余昺鲲; 姜雄伟; 曾慧丹

    2003-01-01

    In this paper, we put emphasis on the analysis the mechanism of the photon-induced frequency conversion β-BaB2O4 crystal inside a borate glass using femtosecond laser. Because of the nature of femtosecond laser's ultra-short pulse duration and high-energy density, in essence the laser-glass interaction mechanism is changed. Based on multiphoton ionization, collisional ionization and the network depolymerization in the borate glass, production of the plasma drives the microstructure rearrangement near the laser beam focusing area. From the structure of glass and crystal analysis, we conclude that the complicated borate groups containing BO3 and BO4 units inside the glass are converted into(B3O6)-3 anion rings.

  1. Abiotic regioselective phosphorylation of adenosine with borate in formamide.

    Furukawa, Yoshihiro; Kim, Hyo-Joong; Hutter, Daniel; Benner, Steven A

    2015-04-01

    Nearly 40 years ago, Schoffstall and his coworkers used formamide as a solvent to permit the phosphorylation of nucleosides by inorganic phosphate to give nucleoside phosphates, which (due to their thermodynamic instability with respect to hydrolysis) cannot be easily created in water by an analogous phosphorylation (the "water problem" in prebiotic chemistry). More recently, we showed that borate could stabilize certain carbohydrates against degradation (the "asphalt problem"). Here, we combine the two concepts to show that borate can work in formamide to guide the reactivity of nucleosides under conditions where they are phosphorylated. Specifically, reaction of adenosine in formamide with inorganic phosphate and pyrophosphate in the presence of borate gives adenosine-5'-phosphate as the only detectable phosphorylated product, with formylation (as opposed to hydrolysis) being the competing reaction. PMID:25826074

  2. Simulation of delayed borated water during a steam line break

    A three-dimensional CFD (computational fluid dynamics) analysis, using FLUENT-6, has been performed on the characteristics of the flow and temperature fields of borated water which is directly injected into the reactor vessel downcomer during a main steam line break (MSLB) accident with the reactor coolant pump (RCP) running mode. The full-scale reactor vessel downcomer model of the APR1400 for boron mixing is tested. The downcomer is modeled as a simplified cylinder annulus including 4 cold leg nozzles and 2 hot leg blunt bodies inside the downcomer annulus. The flow skirt, lower support and the active core parts are modeled as a porous media. The wall heat transfer between the solid to coolant was included in the model. But, the phase changes due to heat transfer are not modeled in this analysis. The objectives of the analysis are to simulate the flow path of the borated water in the upper downcomer during the high pressure safety injection (HPSI) phase, and to evaluate the core bypass phenomena of the borated water in a one-dimensional code analysis. The stagnant vortex flow structures near the cold legs roles are as a flow pass of the borated water in the downcomer. The borated water is passed out well in the high flow region of the cold legs and flows well into the lower downcomer during the RCP running mode. The core bypass of the borated water does not occur during the RCP running mode of a main steam line break condition. Thus, the single and two-channel downcomer models of the one-dimensional system analysis codes might be re-evaluated for a realistic simulation of the steam line break accident. (authors)

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

    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

  4. Glass forming ability of soda lime borate Liquids

    Zheng, Qiuju; Mauro, J. C.; Smedskjær, Morten Mattrup; Potuzak, M.; Keding, Ralf; Yue, Yuanzheng

    2010-01-01

    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). The results show that the GFA decreases when substituting Na2O for B2O3. Moreover, we find that there is no direct link between the kinetic fragility and GFA for the soda lime borate series studied herein....

  5. Spectroscopic studies of tantalum doped borate glasses

    Glasses with formula 30Li2O 60B2O3xTa2O5 (10-x) Bi2O3 for x=0, 2, 4, 6 and 8 were prepared via normal melt quenching technique and characterized by refractive index and MDSC. Refractive index (μ) and glass transition temperature (Tg) are found to increase with increase in dopant concentration. Impedance spectra of the samples were recorded in the frequency range 100 Hz-5 MHz in the temperature range 175-275 °C. The plots are typical of those recorded for disordered systems. Conductivities and relaxation times are found to follow Arrhenius type of relation and activation energies are calculated. Optical absorption spectra were recorded in the wavelength range 200-900 nm range from which cutoff wavelength (λc) and optical band gap energy (Eg) are evaluated. λc is found to decrease while Eg to increase with increase in composition. FTIR spectra of the samples were recorded in the frequency range 400-1500 cm-1 which exhibit characteristic bands corresponding to BO3, BO4 stretching vibrations and BO bending vibration. Tightening of the structure is indicated by increase in the vibration of BO3 at the cost of BO4 for 8 mol% of Ta2O5. This is in support of the highest value of Tg for this sample among the series. Raman spectra of the samples were recorded in the frequency range 200-1200 cm-1. With successive addition of Ta2O5, increase in the vibration of Ta-O groups TaO6 groups to be responsible for observed increase in μ and Tg. An attempt is made to prepare tantalum doped borate glasses and study them by spectroscopic techniques.

  6. Spectroscopic studies of tantalum doped borate glasses

    Sharada, M.; Suresh Babu, D.

    2012-10-01

    Glasses with formula 30Li2O 60B2O3xTa2O5 (10-x) Bi2O3 for x=0, 2, 4, 6 and 8 were prepared via normal melt quenching technique and characterized by refractive index and MDSC. Refractive index (μ) and glass transition temperature (Tg) are found to increase with increase in dopant concentration. Impedance spectra of the samples were recorded in the frequency range 100 Hz-5 MHz in the temperature range 175-275 °C. The plots are typical of those recorded for disordered systems. Conductivities and relaxation times are found to follow Arrhenius type of relation and activation energies are calculated. Optical absorption spectra were recorded in the wavelength range 200-900 nm range from which cutoff wavelength (λc) and optical band gap energy (Eg) are evaluated. λc is found to decrease while Eg to increase with increase in composition. FTIR spectra of the samples were recorded in the frequency range 400-1500 cm-1 which exhibit characteristic bands corresponding to BO3, BO4 stretching vibrations and BO bending vibration. Tightening of the structure is indicated by increase in the vibration of BO3 at the cost of BO4 for 8 mol% of Ta2O5. This is in support of the highest value of Tg for this sample among the series. Raman spectra of the samples were recorded in the frequency range 200-1200 cm-1. With successive addition of Ta2O5, increase in the vibration of Ta-O groups TaO6 groups to be responsible for observed increase in μ and Tg. An attempt is made to prepare tantalum doped borate glasses and study them by spectroscopic techniques.

  7. Thermoluminescent properties of lithium borate, magnesium borate and calcium sulfate developed for temperature sensing

    The objective of this work is to characterize three thermoluminescent (TL) materials synthesized in our laboratory and identified as having properties suitable for temperature sensing, including bright TL emission, low fading at room temperature and low light-induced fading (bleaching) of the TL signal. They are lithium borate doped with copper and silver, Li2B4O7:Cu,Ag (LBO), magnesium borate doped with dysprosium and lithium, MgB4O7:Dy,Li (MBO), and calcium sulfate doped with cerium and terbium, CaSO4:Ce,Tb (CSO). We present their synthesis, powder X-ray diffractograms, TL emission spectra, dose response, and sensitivity to ionizing radiation (compared to commercial LiF:Mg,Ti TL material). Important characteristics for temperature sensing applications, such as fading and bleaching, are presented and discussed. LBO and MBO presented in this work have TL emissions in separate regions of the spectrum, meaning that they can be used simultaneously for temperature measurements, their TL signal being separated in the laboratory using appropriate optical filters. The data presented in this paper provides the supporting basic information required to use these materials in temperature sensing experiments. -- Highlights: • Thermoluminescent (TL) materials were developed for temperature sensing. • Materials have TL intensity comparable or superior to commercial LiF:Mg,Ti. • TL from these materials saturate at higher dose than LiF:Mg,Ti. • TL materials shown minimum fading and light sensitivity. • Data provides basic information to support temperature sensing experiments

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

    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.

  9. Determination Optimum B2O3, KCl and NaOH Molar Ratios in the Synthesis of Potassium Borates

    Kıpçak, Seyhun; Günal, Merve; ILA, Sibel; Yıldırım, Meral; Piskin, Mehmet; Derun, Emek Moroydor

    2015-01-01

    Borates are attention getting chemical compounds because of their properties which leads them a wide usage area. Being sub-group of borates, potassium borates show non-linear optical properties and owing to this they can find applications in optical modulation, optical switching, optical logic and memory, signal processing. Potassium borates can be used in welding, insulation, metal refining and lubricating oil production applications, also.In this study, potassium borates were produced from ...

  10. The development of new NLO crystals in the borate series

    Chen, Chuangtian; Wu, Yicheng; Li, Rukang

    1990-01-01

    It is well known that the inorganic borates exist in numerous structural types, and some crystals such as KB5 (KB 5O 8·4H 2O) and BBO(β-BaB 2O 4) are excellent nonlinear optical (NLO) materials, particularly in the ultraviolet region. In this review, we are going to approach our topic from the anionic group theory, which we have begun to develop in the late 1960's. A systematic classification has been made of the borate series in terms of the structural types of the anionic groups. Calculations have been made for the linear and NLO properties for most of the important borate anionic groups, including second-order susceptibilities and absorption edges in the ultraviolet spectral region. We have therefore been led to the formulation of a series of structural criteria, which serve as useful guidelines for the screening, characterization, and development of certain borate crystals, such as BBO (β-BaB 2O 4, i.e., BaB 2O 4 in its low-temperature modification) and LBO (LiB 3O 5) as new materials. The characteristic features of BBO and LBO crystals, excellent NLO materials developed during the past few years in China at the Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, are also discussed.

  11. Study Of The PWR Fuel Bundle Characteristic With Borated Water

    Study of the PWR fuel bundle characteristic with 2,4, 2,6, 2,8, 3,0, 3,2 and 3,4 enrichment also with borated water 150 and 200 ppm has been done. The fuel bundle contained 264 fuel elements and water (no fuel elements) are arranged as 17 x 17 matrix and 30,294 cm. The fuel bundle characteristic can be seen from their group constants and the infinite multiplication factor whether more or less than one. The fuel bundle parameters can be found from cell calculation with WIMS PC version program. From the cell calculation shown that the infinite multiplication factor of the fuel bundle with 2,4% enrichment and 200 ppm borated water is 1, 01672, its shown that infinite multiplication factor will less than one with increasing borated water more than 200 ppm. From these result if we would like to design the reactor core with 2,4% minimum enrichment then the maximum borated water is 200 ppm

  12. Effect of gamma ray irradiation on sodium borate single crystals

    Kalidasan, M.; Asokan, K.; Baskar, K.; Dhanasekaran, R.

    2015-12-01

    In this work, the effects of 5 kGy, 10 kGy and 20 kGy doses of gamma ray irradiation on sodium borate, Na2[B4O5(OH)4]·(H2O)8 single crystals have been studied. Initially these crystals were grown by solution growth technique and identified as monoclinic using X-ray diffraction analysis. X-ray rocking curves confirm the formation of crystalline defects due to gamma rays in sodium borate single crystals. The electron paramagnetic resonance spectra have been recorded to identify the radicals created due to gamma ray irradiation in sodium borate single crystals. The thermoluminescence glow curves due to the defects created by gamma rays in this crystal have been observed and their kinetic parameters were calculated using Chen's peak shape method. The optical absorption increases and photoluminescence spectral intensity decreases for 5 kGy and 20 kGy doses gamma ray irradiated crystals compared to pristine and 10 kGy dose irradiated one. The effect of various doses of gamma rays on vibrational modes of the sodium borate single crystals was studied using FT-Raman and ATR-FTIR spectral analysis. The dielectric permittivity, conductance and dielectric loss versus frequency graphs of these crystals have been analyzed to know the effect of gamma ray irradiation on these parameters.

  13. Spectroscopic studies of tantalum doped borate glasses

    Sharada, M. [Department of Physics, Nizam College, Osmania University, Hyderabad (India); Suresh Babu, D. [Department of Physics, Nizam College, Osmania University, Hyderabad (India)

    2012-10-01

    Glasses with formula 30Li{sub 2}O 60B{sub 2}O{sub 3}xTa{sub 2}O{sub 5} (10-x) Bi{sub 2}O{sub 3} for x=0, 2, 4, 6 and 8 were prepared via normal melt quenching technique and characterized by refractive index and MDSC. Refractive index ({mu}) and glass transition temperature (T{sub g}) are found to increase with increase in dopant concentration. Impedance spectra of the samples were recorded in the frequency range 100 Hz-5 MHz in the temperature range 175-275 Degree-Sign C. The plots are typical of those recorded for disordered systems. Conductivities and relaxation times are found to follow Arrhenius type of relation and activation energies are calculated. Optical absorption spectra were recorded in the wavelength range 200-900 nm range from which cutoff wavelength ({lambda}{sub c}) and optical band gap energy (E{sub g}) are evaluated. {lambda}{sub c} is found to decrease while E{sub g} to increase with increase in composition. FTIR spectra of the samples were recorded in the frequency range 400-1500 cm{sup -1} which exhibit characteristic bands corresponding to BO{sub 3}, BO{sub 4} stretching vibrations and BO bending vibration. Tightening of the structure is indicated by increase in the vibration of BO{sub 3} at the cost of BO{sub 4} for 8 mol% of Ta{sub 2}O{sub 5}. This is in support of the highest value of T{sub g} for this sample among the series. Raman spectra of the samples were recorded in the frequency range 200-1200 cm{sup -1}. With successive addition of Ta{sub 2}O{sub 5}, increase in the vibration of Ta-O groups TaO{sub 6} groups to be responsible for observed increase in {mu} and T{sub g}. An attempt is made to prepare tantalum doped borate glasses and study them by spectroscopic techniques.

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

    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 Li6Y(BO3)3 and two oxy-borates: LiY6O5(BO3)3 and Y17,33B8O38. 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 Li6Y(BO3)3: Yb3+. 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 Li6Y(BO3)3: Yb3+ crystal are reported. (author)

  15. Enhancing mechanical properties of ceramic papers loaded with zeolites using borate compounds as binders

    Juan P. Cecchini; Ramiro M. Serra; María A. Ulla; Miguel A. Zanuttini; Viviana G. Milt

    2013-01-01

    NaY zeolite-containing ceramic papers were prepared by a papermaking technique with a dual polyelectrolyte retention system that implied the use of cationic and anionic polymers. To improve their mechanical properties, we found that some borate compounds could be successfully used as ceramic binders. Three types of sodium and/or calcium borates were tested as binders: colemanite, nobleite, and anhydrous ulexite. The improvement in the mechanical properties depends both on the borate used and ...

  16. Borate esters as convenient reagents for direct amidation of carboxylic acids and transamidation of primary amides

    Starkov, P.; Sheppard, T. D.

    2011-01-01

    Simple borates serve as effective promoters for amide bond formation with a variety of carboxylic acids and amines. With trimethyl or tris(2,2,2-trifluoroethyl) borate, amides are obtained in good to excellent yield and high purity after a simple work-up procedure. Tris(2,2,2-trifluoroethyl) borate can also be used for the straightforward conversion of primary amides to secondary amides via transamidation.

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

    Azmi Seyhun Kipcak; Derya Yilmaz Baysoy; Emek Moroydor Derun; Sabriye Piskin

    2013-01-01

    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 (...

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

    Mārtiņš Kaprāns

    2011-01-01

    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 stylisti...

  19. Could borate have played a role in the RNA World?

    Grew, E. S.; Bada, J. L.; Hazen, R. M.

    2012-12-01

    Two scenarios have been proposed for boron to play a critical role in the stabilization of ribose and other sugars in the ribonucleic acid (RNA) World, >3.8 Ga ago. One scenario envisages oligomeric RNA being synthesized in subaerial intermountane desert valleys in which groundwater was enriched in borate from breakdown of tourmaline (Benner et al. 2012 doi: 10.1021/ar200332w). In the alternative scenario, borates are enriched in hydrothermal environments (3.8 Ma as they are today and (2) plate tectonics was the prevailing regime. The postulated non-marine borate deposits would have been associated with continental collision and subduction with volcanism releasing B, whereas in the second scenario, ocean floor caught up in an early phase of subduction is considered a favorable site for borate formation. Because borate deposits are typically ephemeral and poorly preserved, the lack of evidence in the geologic record for these scenarios does not invalidate them. For example, the oldest reported non-marine borate deposits analogous to the type postulated in first scenario are only 20 Ma, but metamorphosed borates of Precambrian age have been interpreted to have non-marine evaporite precursors, the oldest being 2.4-2.1 Ga in the Liaoning-Jilin area, China. The first B minerals so far reported in the geologic record are metamorphic dravite-schorl tourmalines in the 3.7-3.8 Ga Isua supracrustal belt (southern West Greenland), where there is good evidence for seafloor spreading and subduction. The precursors to the Isua tourmalines are reported to include B-bearing marine clay minerals and detrital tourmaline. The relatively high Li contents in zircon from Jack Hills, Australia, have been cited as evidence for the presence of granitic (s. l.) "protocontinental" crust by 4.3 Ga (Ushikuba et al. 2008 doi:10.1016/j.epsl.2008.05.032; Valley et al. 2010 Rec Geol Surv W Aust, 5-7), but the existence of conventional plate tectonics prior to 3.8 Ga remains controversial

  20. Optical properties of Tm 3+ ions in lithium borate glasses

    Jayasankar, C. K.; Renuka ^Devi, A.

    1996-09-01

    Optical properties of Tm 3+ ions are investigated in the following lithium borate (LBO) glasses: Li 2CO 3 + H 3BO 3 and MCO 3 + Li 2CO 3 + H 3BO 3 (M = Mg, Ca, Sr and Ba). The assigned energy level data of Tm 3+ (4f 12) in these borate glasses as well as the data that are available for some other systems in the literature are analysed in terms of a parametrized Hamiltonian model that includes 14 free-ion parameters. The absorption linestrengths are measured for Tm 3+:LBO glasses. Using these data, intensity parameters (Ω λ, λ = 2, 4, 6), radiative transition probabilities, radiative lifetimes, fluorescence branching ratios and integrated absorption cross-sections for fluorescent levels of Tm 3+:LBO glasses are calculated by applying Judd-Ofelt theory. The effect of glass network formers and glass modifiers on the optical properties of Tm 3+:glasses are discussed.

  1. FTIR of binary lead borate glass: Structural investigation

    Othman, H. A.; Elkholy, H. S.; Hager, I. Z.

    2016-02-01

    The glass samples were prepared according to the following formula: (100-x) B2O3 - x PbO, where x = 20-80 mol% by melt quenching method. The density of the prepared samples was measured and molar volume was calculated. IR spectra were measured for the prepared samples to investigate the glass structure. The IR spectra were deconvoluted using curves of Gaussian shape at approximately the same frequencies. The deconvoluted data were used to study the effect of PbO content on all the structural borate groups. Some structural parameters such as density, packing density, bond length and bond force constant were theoretically calculated and were compared to the obtained experimental results. Deviation between the experimental and theoretically calculated parameters reflects the dual role of PbO content on the network of borate glass.

  2. Synthesis and studies on microhardness of alkali zinc borate glasses

    The mixed alkali effect on zinc borate glasses have been reported. The glass systems of nominal composition 10Zn+xLi2O+yNa2O+80B2O3 (x = y = 0, 5, 10, 15 mol%) were prepared using standard melt quenching method. The structural, physical and mechanical properties of the samples have been studied using X-ray diffraction(XRD), density measurement and Vickers hardness measurement, respectively. A consistent increase in the density was observed, which explains the role of the modifiers (Li2O and Na2O) in the network modification of borate structure. The molar volume is decreasing linearly with the alkali concentration, which is attributed to the conversion of tetrahedral boron (BO4/2)− into (BO3/2)−. The microhardness studies reveals the anisotropy nature of the material. It further confirms that the samples belong to hard glass category

  3. Synthesis and studies on microhardness of alkali zinc borate glasses

    Subhashini, Bhattacharya, Soumalya; Shashikala, H. D.; Udayashankar, N. K.

    2014-04-01

    The mixed alkali effect on zinc borate glasses have been reported. The glass systems of nominal composition 10Zn+xLi2O+yNa2O+80B2O3 (x = y = 0, 5, 10, 15 mol%) were prepared using standard melt quenching method. The structural, physical and mechanical properties of the samples have been studied using X-ray diffraction(XRD), density measurement and Vickers hardness measurement, respectively. A consistent increase in the density was observed, which explains the role of the modifiers (Li2O and Na2O) in the network modification of borate structure. The molar volume is decreasing linearly with the alkali concentration, which is attributed to the conversion of tetrahedral boron (BO4/2)- into (BO3/2)-. The microhardness studies reveals the anisotropy nature of the material. It further confirms that the samples belong to hard glass category.

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

    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.

  5. Infrared spectra of zinc doped lead borate glasses

    S G Motke; S P Yawale; S S Yawale

    2002-02-01

    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 coordination was not observed. The conversion of three-fold to four-fold coordinated boron took place.

  6. Coordination chemistry of poly(thioether)borate ligands

    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, C...

  7. The new silver borate Ag3B5O9

    Single crystals of Ag3B5O9 were obtained via high-pressure synthesis at 3 GPa and 600 °C, using a Walker-type multianvil high-pressure device. Ag3B5O9 crystalizes with a=674.7(2), b=943.5(2), c=1103.5(2) pm, V=0.7025(2) nm3, and Z=4 in the noncentrosymmetric space group P212121 (no. 19). The orthorhombic structure was refined from 3740 independent reflections with R1=0.0496 and wR2=0.587 (all data). It is built up from infinite corner-sharing chains of BO4 tetrahedra along the a axis, which are interconnected by BO3 groups to form a network. In the structure, three crystallographically independent sites are occupied with Ag+ cations exhibiting argentophillic interactions. The synthetic conditions as well as the results of the single crystal structure analysis are presented. - Graphical abstract: Noncentrosymmetric silver borate: During investigations in the system Ag–B–O, a new noncentrosymmetric silver borate Ag3B5O9 was discovered. The new structure type is built up from corner-sharing BO3 and BO4 groups, forming a network. Argentophillic interactions are clearly indicated by the Ag+⋯Ag+ distances present in the structure. - Highlights: • A noncentrosymmetric borate Ag3B5O9 is accessible via high-pressure synthesis. • Ag3B5O9 is the second high-pressure silver borate. • Ag+⋯Ag+ distances in Ag3B5O9 clearly indicate the presence of argentophillic interactions

  8. Synthesis, characterisation, electrical and optical properties of copper borate compounds

    Highlights: • Cu(BO2)2 was synthesized at the form of with pdf number of “00-001-0472”. • Particle sizes were found between 162.72 and 56.44 nm and 195.76 and 75.73 nm at CuSNaH. • Reaction yields were 90.4 ± 0.84, 96.9 ± 0.78 and 78.9 ± 0.76% for CuST, CuSB and CuSNaH. • The resistivity of CuST, CuSB and CuSNaH are 1.10 × 107, 7.02 × 106 and 8.62 × 105 Ωm. • The optical energy gap was 3.76 eV. - Abstract: The hydrothermal synthesis of copper borate compounds [Cu(BO2)2] was studied, and several parameters were found to affect the synthesis. Raw materials, including CuSO4·5H2O, Na2B4O7·5H2O, Na2B4O7·10H2O, NaOH and H3BO3, were used. Reaction temperatures and reaction times between 40 °C and 100 °C and 15 and 240 min, respectively, were used. The as-synthesised copper borate was analysed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The yields of the reactions were also calculated. Single-phase, nanoparticulate copper borate compounds (Cu(BO2)2) possessing high XRD crystal scores were obtained; the reactions used to obtain these materials were highly efficient. Electrical resistivity and optical absorbance measurements were carried out on the compounds obtained from the highest yielding reactions. The results of this study showed that even using a reaction time of 15 min, copper borate formation was successfully achieved

  9. G4-quartet·M(+) borate hydrogels.

    Peters, Gretchen Marie; Skala, Luke P; Plank, Taylor N; Oh, Hyuntaek; Reddy, G N Manjunatha; Marsh, Andrew; Brown, Steven P; Raghavan, Srinivasa R; Davis, Jeffery T

    2015-05-01

    The ability to modulate the physical properties of a supramolecular hydrogel may be beneficial for biomaterial and biomedical applications. We find that guanosine (G 1), when combined with 0.5 equiv of potassium borate, forms a strong, self-supporting hydrogel with elastic moduli >10 kPa. The countercation in the borate salt (MB(OH)4) significantly alters the physical properties of the hydrogel. The gelator combination of G 1 and KB(OH)4 formed the strongest hydrogel, while the weakest system was obtained with LiB(OH)4, as judged by (1)H NMR and rheology. Data from powder XRD, (1)H double-quantum solid-state magic-angle spinning (MAS) NMR and small-angle neutron scattering (SANS) were consistent with a structural model that involves formation of borate dimers and G4·K(+) quartets by G 1 and KB(OH)4. Stacking of these G4·M(+) quartets into G4-nanowires gives a hydrogel. We found that the M(+) cation helps stabilize the anionic guanosine-borate (GB) diesters, as well as the G4-quartets. Supplementing the standard gelator mixture of G 1 and 0.5 equiv of KB(OH)4 with additional KCl or KNO3 increased the strength of the hydrogel. We found that thioflavin T fluoresces in the presence of G4·M(+) precursor structures. This fluorescence response for thioflavin T was the greatest for the K(+) GB system, presumably due to the enhanced interaction of the dye with the more stable G4·K(+) quartets. The fluorescence of thioflavin T increased as a function of gelator concentration with an increase that correlated with the system's gel point, as measured by solution viscosity. PMID:25871426

  10. Glass-Forming Ability of Soda Lime Borate Liquids

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

    2012-01-01

    results show that the GFA decreases when substituting Na2O for B2O3. Moreover, we find that there is no direct link between the kinetic fragility and GFA for the soda lime borate series studied herein. We have also discovered and clarified a striking thermal history dependence of the glass stability...... slowly cooling their melts to the glassy state, before any reheating. We explain this phenomenon in terms of the thermal history dependence of boron speciation....

  11. Potassium zinc borate, KZnB3O6

    Yang Wu

    2010-05-01

    Full Text Available The title compound, KZnB3O6 contains a remarkable [B6O12]6− group (overline{1} symmetry formed by two rings linked by edge-sharing BO4 tetrahedra, a feature that has only been observed previously under high pressure conditions. These borate groups are connected through distorted ZnO4 tetrahedra in edge-shared pairs (overline{1} symmetry, forming a three-dimensional network whose cavities are filled by K+ cations.

  12. Potassium zinc borate, KZnB(3)O(6).

    Wu, Yang; Yao, Ji-Yong; Zhang, Jian-Xiu; Fu, Pei-Zhen; Wu, Yi-Cheng

    2010-01-01

    The title compound, KZnB(3)O(6) contains a remarkable [B(6)O(12)](6-) group ( symmetry) formed by two rings linked by edge-sharing BO(4) tetra-hedra, a feature that has only been observed previously under high pressure conditions. These borate groups are connected through distorted ZnO(4) tetra-hedra in edge-shared pairs ( symmetry), forming a three-dimensional network whose cavities are filled by K(+) cations. PMID:21578991

  13. Thermoluminescence properties of alkali borate glasses containing neodymium

    The thermoluminescence properties of sodium borate glasses as a function of neodymium oxide content as well as the divalent metal oxides (RO = ZnO, MgO and CaO) in replacement of Na2O have been investigated. It is observed that the addition of Nd2O3 imparts to the host glass a monopeak glow curve according to an active luminescent centre (E ≅ 0.97 eV to 1.232 eV). The gradual addition of neodymium oxide to the sodium borate glass causes gradual enhancement in the TL-intensity up to a quenching concentration value (4 g Nd2O3 added to 100 g of borate glass) above which a draw back in TL-intensity occurs. On the other hand the replacement of 5 wt% Na2O by RO shows that CaO dominates the other two divalent metal oxides used, as it possesses a much deeper luminescent trap (1.232 eV). The results obtained suggest that these glasses can be used in radiation detection and dosimetry. The γ-induced Tl-signal of such type of glass is found to be reproducible within an acceptable error of not more than 3.5% in all individual and group scattering over the detector samples each of which is used 10 times for evaluating the same γ-dose. (orig./HP)

  14. Granulation of Dried Borate Concentrates from Nuclear Power Plants

    Borate concentrated wastes generated from liquid waste evaporator of 12 pressurized water reactors (PWRs) have been processed to be dry using concentrated waste drying system (CWDS) in Korea. Borate wastes had been stabilized or solidified using paraffin as a binder since 1995, but the solidification process is stopped and concentrated wastes are just stored in drums and on standby at present because paraffin waste forms have some sorts of problems such as heterogeneous forming (stratification), low compressive strength, and high leaching rate. According to No. 2005-18 of Notices of the Ministry of Science and Technology (MOST), all of low- and intermediate level waste (LILW) forms must satisfy the requirement of solidification before they are delivered to the final repository in Kyeongju. In this study, polymer solidification technology is proposed to treat borate concentrated wastes. Originally, this technology has been developed and used to solidify the spent ion exchange resin in many countries. Most commercial polymer binders include epoxy, polyester and viny lester styrene, etc. Recently in May 2003, Idaho National Engineering and Environmental Laboratory (INEEL) issued a report confirming that APSTM(Diversified Technologies Services), a kind of polymer waste form, met the NRC's Waste Form requirements for Class B and C wastes. The Conference of Radiation Control Program Directors (CRCPD) reviewed the INEEL report, and the E-5 Committee issued a letter of waste form approval for the APSTM process. This serves as a national approval in the US, replacing the now defunct NRC Topical Report Program

  15. Study on optical weak absorption of borate crystals

    Li, Xiaomao; Hu, Zhanggui; Yue, Yinchao; Yu, Xuesong; Lin, Zheshuai; Zhang, Guochun

    2013-10-01

    Borate crystal is an important type of nonlinear optical crystals used in frequency conversion in all-solid-state lasers. Especially, LiB3O5 (LBO), CsB3O5 (CBO) and CsLiB6O10 (CLBO) are the most advanced. Although these borate crystals are all constructed by the same anionic group-(B3O7)5-, they show different nonlinear optical properties. In this study, bulk weak absorption values of three borate crystals have been studied at 1064 nm by a photothermal common-path interferometer. The bulk weak absorption values of them along [1 0 0], [0 1 0] and [0 0 1] directions were obtained, respectively, to be approximately 17.5 ppm cm-1, 15 ppm cm-1 and 20 ppm cm-1 (LBO); 80 ppm cm-1, 100 ppm cm-1 and 40 ppm cm-1 (CBO); 600 ppm cm-1, 600 ppm cm-1 and 150 ppm cm-1 (CLBO) at 1064 nm. The results showed an obvious discrepancy of the values of these crystals along three axis directions. A correlation between the bulk weak absorption property and crystal intrinsic structure was then discussed. It is found that the bulk weak absorption values strongly depend on the interstitial area surrounded by the B-O frames. The interstitial area is larger, the bulk weak absorption value is higher.

  16. Solidification of radioactive borated waste concentrates from pressurized water reactors

    New mixtures for solidification of borated waste concentrates have been developed under a Nagra contract by EIR in conjunction with staff of Beznau power station where the wastes are produced. The objective of the project was to find a solidification recipe which best enabled the wastes to fulfill the necessary conditions for geologic disposal with respect to their mechanical strength, water resistance, sulphate resistance, long-term stability and leachability. Boric acid or borates in concentrates require additional calcium hydroxide in cements used for solidification so that precipitation of calcium metaborate which is necessary for hardening will take place. An initial scoping study was performed on inactive concentrates before the range of cements and additives was further reduced in a second series of experiments. With active concentrates, 11 recipes were tested, including measurement of leach rates. Addition of Trass in the ratio to cement of 30:100 reduced caesium leach rates by around 2 orders of magnitude. The chosen mixture A.11. was then tested on a technological scale. In 200 l drums at the Beznau facility mixing and stirring techniques leading to hardening in acceptable times were established. The hardening process and the temperatures were monitored. The strength, water resistance and sulphate resistance were measured for the mix from the drum. Since the beginning of 1982 the method has been in use for borated concentrates at Beznau with the approval of the safety authorities. The method is being patented; further details are available from the author. (author)

  17. Capacity gradient anion chromatography with a borate complex as eluent.

    Yamamoto, A; Inoue, Y; Kodama, S; Matsunaga, A

    1999-07-30

    Complex formation between borate compounds and vicinal diols is well recognized. Generally, in a chemically bonded anion-exchange resin, many hydroxyl groups are introduced on the surface of the resin in order to make the resin hydrophilic. The borate as an eluting reagent also reacts to these hydroxyl groups, and this complex formation decreases the apparent ion-exchange capacity of the column by being dissociated to the anion depending on the eluent pH. In the present work a method is described for the simultaneous determination of anions based on the capacity gradient for suppressed ion chromatography. A Tosoh IC-Anion-PW column and dihydroxyphenylborane-mannitol eluent system were used. To maintain baseline stability, it was helpful to keep the borate concentration constant during a gradient of 16 to 0 mM mannitol as a modifier to prevent the complex formation with the hydroxyl on the resin. The chemical composition of the eluents and gradient profiles are discussed and the application to the analysis of the condensed phosphates with widely varying retention times as food additives in a cheese sample is presented. PMID:10457467

  18. Production of fine zinc borate in industrial scale

    Çakal Gaye Ö.

    2012-01-01

    Full Text Available In this study, zinc borate production in an industrial scale batch reactor was carried out at the optimum process conditions determined in the previous studies performed at the laboratory and pilot scale reactors. The production was done via the heterogeneous reaction of boric acid and zinc oxide. The samples were characterized by chemical analysis, XRD, TGA, SEM and particle size distribution. The final product which was obtained in the industrial scale reactor was 2ZnO.3B2O3.3H2O. The kinetic data for the zinc borate production reaction fit to a modified logistic model where the lag time was taken into account. As observed, the reaction time was influenced by scaling up. There was a lag time of 120 min for the industrial scale production and thus, the reaction completion time was 70 min longer compared to pilot scale. It should be emphasized that the specific reaction rate, k; as well as the average particle size and the hydration temperature of zinc borate are unaffected by scale up.

  19. Syntheses and crystal structures of two new organically templated borates

    Two new organically templated borates, [H3N(C6H10)NH3][B4O5(OH)4] (1) and [H3N(C6H10)NH3][B5O8(OH)] (2) have been synthesized in the presence of trans-1,4-diaminocyclohexane acting as a structure-directing agent under mild solvothermal conditions. The structures were determined by single crystal X-ray diffraction and further characterized by FTIR, elemental analysis and thermogravimetric analysis. Compound 1 crystallizes in the monoclinic system, space group C2/c (No. 15), a=9.1325(3)A, b=11.4869(3)A, c=12.2756(5)A, β=105.258(6)o, V=1242.37(7)A3, Z=4. The structure contains supramolecular hydrogen-bonded network formed by isolated [B4O5(OH)4]2- polyanions. 2 is monoclinic, space group P2(1)/n (No. 14), a=6.5176(2)A, b=16.8861(5)A, c=11.1522(7)A, β=91.897(6)o, V=1226.70(9)A3, Z=4. The structure consists of layers of 3,9-membered boron rings constructed from pentaborate anion groups [B5O8(OH)]2-. The adjacent borate layers are further linked with each other by hydrogen bond to form a 3D supramolecular network. It is the first example of layered borates templated by an organic amine

  20. Evaluation of putative inhibitors of mitochondrial permeability transition for brain disorders--specificity vs. toxicity.

    Morota, Saori; Månsson, Roland; Hansson, Magnus J; Kasuya, Kazuhiko; Shimazu, Motohide; Hasegawa, Erika; Yanagi, Shigeru; Omi, Akibumi; Uchino, Hiroyuki; Elmér, Eskil

    2009-08-01

    Inhibition of mitochondrial permeability transition (mPT) has emerged as a promising approach for neuroprotection and development of well-tolerated mPT inhibitors with favorable blood-brain barrier penetration is highly warranted. In a recent study, 28 clinically available drugs with a common heterocyclic structure were identified as mPT inhibitors e.g. trifluoperazine, promethazine and nortriptyline. In addition, neuroprotection by structurally unrelated drugs e.g. neurosteroids, 4-hydroxy-tamoxifen and trimetazidine has been attributed to direct inhibition of mPT. The regulation of mPT is complex and highly dependent on the prevailing experimental conditions. Several features of mPT, such as swelling, depolarization or NADH oxidation, can also occur independently of the mPT phenomenon. Here, in isolated rodent brain-derived and human liver mitochondria, we re-evaluate drugs promoted as potent mPT inhibitors. We address the definition of an mPT inhibitor and present strategies to reliably detect mPT inhibition in vitro. Surprisingly, none of the 12 compounds tested displayed convincing mPT inhibition or effects comparable to cyclophilin D inhibition by the non-immunosuppressive cyclophilin inhibitor D-MeAla(3)-EtVal(4)-Cyclosporin (Debio 025). Propofol and 2-aminoethoxydiphenyl borate (2-APB) inhibited swelling in de-energized mitochondria but did not increase calcium retention capacity (CRC). Progesterone, trifluoperazine, allopregnanolone and 4-hydroxy-tamoxifen dose-dependently reduced CRC and respiratory control and were thus toxic rather than beneficial to mitochondrial function. Interestingly, topiramate increased CRC at high concentrations likely by a mechanism separate from direct mPT inhibition. We conclude that a clinically relevant mPT inhibitor should have a mitochondrial target and increase mitochondrial calcium retention at concentrations which can be translated to human use. PMID:19348797

  1. Intracellular calcium release modulates polycystin-2 trafficking

    Miyakawa Ayako

    2013-02-01

    Full Text Available Abstract Background Polycystin-2 (PC2, encoded by the gene that is mutated in autosomal dominant polycystic kidney disease (ADPKD, functions as a calcium (Ca2+ permeable ion channel. Considerable controversy remains regarding the subcellular localization and signaling function of PC2 in kidney cells. Methods We investigated the subcellular PC2 localization by immunocytochemistry and confocal microscopy in primary cultures of human and rat proximal tubule cells after stimulating cytosolic Ca2+ signaling. Plasma membrane (PM Ca2+ permeability was evaluated by Fura-2 manganese quenching using time-lapse fluorescence microscopy. Results We demonstrated that PC2 exhibits a dynamic subcellular localization pattern. In unstimulated human or rat proximal tubule cells, PC2 exhibited a cytosolic/reticular distribution. Treatments with agents that in various ways affect the Ca2+ signaling machinery, those being ATP, bradykinin, ionomycin, CPA or thapsigargin, resulted in increased PC2 immunostaining in the PM. Exposing cells to the steroid hormone ouabain, known to trigger Ca2+ oscillations in kidney cells, caused increased PC2 in the PM and increased PM Ca2+ permeability. Intracellular Ca2+ buffering with BAPTA, inositol 1,4,5-trisphosphate receptor (InsP3R inhibition with 2-aminoethoxydiphenyl borate (2-APB or Ca2+/Calmodulin-dependent kinase inhibition with KN-93 completely abolished ouabain-stimulated PC2 translocation to the PM. Conclusions These novel findings demonstrate intracellular Ca2+-dependent PC2 trafficking in human and rat kidney cells, which may provide new insight into cyst formations in ADPKD.

  2. Extracellular ATP-induced nuclear Ca{sup 2+} transient is mediated by inositol 1,4,5-trisphosphate receptors in mouse pancreatic {beta}-cells

    Chen, Zheng; Li, Zhengzheng; Peng, Gong; Chen, Xiaoli; Yin, Wenxuan [National Laboratory of Biomacromolecules, Institute of Biophysics of Chinese Academy of Sciences, 15 Datun Rd., Beijing 100101 (China); Kotlikoff, Michael I. [Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853 (United States); Yuan, Zeng-qiang, E-mail: zqyuan@sun5.ibp.ac.cn [National Laboratory of Biomacromolecules, Institute of Biophysics of Chinese Academy of Sciences, 15 Datun Rd., Beijing 100101 (China); Ji, Guangju, E-mail: gj28@ibp.ac.cn [National Laboratory of Biomacromolecules, Institute of Biophysics of Chinese Academy of Sciences, 15 Datun Rd., Beijing 100101 (China)

    2009-05-01

    Extracellular ATP (eATP) induces an intracellular Ca{sup 2+} transient by activating phospholipase C (PLC)-associated P2X4 purinergic receptors, leading to production of inositol 1,4,5-trisphosphate (IP3) and subsequent Ca{sup 2+} release from intracellular stores in mouse pancreatic {beta}-cells. Using laser scanning confocal microscopy, Ca{sup 2+} indicator fluo-4 AM, and the cell permeable nuclear indicator Hoechst 33342, we examined the properties of eATP-induced Ca{sup 2+} release in pancreatic {beta}-cell nuclei. eATP induced a higher nuclear Ca{sup 2+} transient in pancreatic {beta}-cell nuclei than in the cytosol. After pretreatment with thapsigargin (TG), an inhibitor of sarco-endoplasmic reticulum Ca{sup 2+}-ATPase (SERCA) pumps, the amplitude of eATP-induced Ca{sup 2+} transients in the nucleus was still much higher than those in the cytosol. This effect of eATP was not altered by inhibition of either the plasma membrane Ca{sup 2+}-ATPase (PMCA) or the plasma membrane Na{sup +}/Ca{sup 2+} exchanger (NCX) by LaCl{sub 3} or by replacement of Na{sup +} with N-Methyl-Glucosamine. eATP-induced nuclear Ca{sup 2+} transients were abolished by a cell-permeable IP3R inhibitor, 2-aminoethoxydiphenyl borate (2-APB), but were not blocked by the ryanodine receptor (RyR) antagonist ryanodine. Immunofluorescence studies showed that IP3Rs are expressed on the nuclear envelope of pancreatic {beta}-cells. These results indicate that eATP triggers nuclear Ca{sup 2+} transients by mobilizing a nuclear Ca{sup 2+} store via nuclear IP3Rs.

  3. Echinacea-induced cytosolic Ca2+ elevation in HEK293

    Nikolau Basil J

    2010-11-01

    Full Text Available Abstract Background With a traditional medical use for treatment of various ailments, herbal preparations of Echinacea are now popularly used to improve immune responses. One likely mode of action is that alkamides from Echinacea bind to cannabinoid type 2 (CB2 receptors and induce a transient increase in intracellular Ca2+. Here, we show that unidentified compounds from Echinacea purpurea induce cytosolic Ca2+ elevation in non-immune-related cells, which lack CB2 receptors and that the Ca2+ elevation is not influenced by alkamides. Methods A non-immune human cell line, HEK293, was chosen to evaluate E. purpurea root extracts and constituents as potential regulators of intracellular Ca2+ levels. Changes in cytosolic Ca2+ levels were monitored and visualized by intracellular calcium imaging. U73122, a phospholipase C inhibitor, and 2-aminoethoxydiphenyl borate (2-APB, an antagonist of inositol-1,4,5-trisphosphate (IP3 receptor, were tested to determine the mechanism of this Ca2+ signaling pathway. E. purpurea root ethanol extracts were fractionated by preparative HPLC, screened for bioactivity on HEK293 cells and by GC-MS for potential constituent(s responsible for this bioactivity. Results A rapid transient increase in cytosolic Ca2+ levels occurs when E. purpurea extracts are applied to HEK293 cells. These stimulatory effects are phospholipase C and IP3 receptor dependent. Echinacea-evoked responses could not be blocked by SR 144528, a specific CB2 receptor antagonist, indicating that CB2 is not involved. Ca2+ elevation is sustained after the Echinacea-induced Ca2+ release from intracellular Ca2+ stores; this longer-term effect is abolished by 2-APB, indicating a possible store operated calcium entry involvement. Of 28 HPLC fractions from E. purpurea root extracts, six induce cytosolic Ca2+ increase. Interestingly, GC-MS analysis of these fractions, as well as treatment of HEK293 cells with known individual and combined chemicals, indicates the

  4. 76 FR 69292 - Aging Management of Stainless Steel Structures and Components in Treated Borated Water

    2011-11-08

    .... ML100920158), for which a notice of availability was published in the Federal Register on June 22, 2010 (75 FR... COMMISSION Aging Management of Stainless Steel Structures and Components in Treated Borated Water AGENCY... Components in Treated Borated Water.'' This LR-ISG revises the guidance in the Standard Review Plan...

  5. 77 FR 27815 - Aging Management of Stainless Steel Structures and Components in Treated Borated Water

    2012-05-11

    ... COMMISSION Aging Management of Stainless Steel Structures and Components in Treated Borated Water AGENCY..., ``Aging Management of Stainless Steel Structures and Components in Treated Borated Water.'' This LR-ISG... Register on June 22, 2010 (75 FR 35510). The NRC staff has determined that existing guidance in the...

  6. 76 FR 74831 - Aging Management of Stainless Steel Structures and Components in Treated Borated Water

    2011-12-01

    ... COMMISSION Aging Management of Stainless Steel Structures and Components in Treated Borated Water AGENCY...: On November 8, 2011 (76 FR 69292) the U.S. Nuclear Regulatory Commission (NRC) published in the...- ISG-2011-01, ``Aging Management of Stainless Steel Structures and Components in Treated Borated...

  7. Conditioning highly concentrated borate solutions with calcium sulfo-aluminate cement

    The early age hydration by borate solution of 3 calcium sulfo-aluminate cements (CSA), containing respectively 0%, 10% and 20% of gypsum by weight of cement was studied using isothermal calorimetry and dynamic mode rheo-metry. XRD and TGA analysis were carried out on pastes with increasing hydration degrees (up to 90 days) to specify the mineralogy and to figure out the mechanisms of borate immobilisation. It has been shown that the retarding effect of borate anions is due to the precipitation of the amorphous calcium borate C2B3H8; borate anions were then incorporated in Aft-type phases. The macroscopic properties of hydrated binders (compressive strength, length change) were also followed during 180 days. It appears that the mechanical strength continuously increases with the hydration degree. Length changes under wet-curing and sealed bag remain moderate and seem to be stabilized after 180 days

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

    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 11B boric acid for the neutron diffraction measurements. The data presented here were from X-ray diffraction (CuKα 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)

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

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

    2013-01-01

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

  10. Frottement interne des verres de borates et de borosilicates alcalins

    Phalippou, J.; Jabra, R.; Zarzycki, J.

    1980-01-01

    Les spectres de frottement interne des verres de borates alcalins ont été étudiés en fonction de la température. Ces spectres, contrairement à ceux des silicates et phosphates alcalins, ne montrent pas de second maximum (haute température). Il en est de même pour certains borosilicates alcalins. L'étude structurale de ces matériaux et en particulier du type de groupements hydroxyles qui peuvent y être rencontrés, nous incite à penser que le second maximum de frottement interne est dû à la pré...

  11. Functionalization of closo-Borates via Iodonium Zwitterions.

    Kaszyński, Piotr; Ringstrand, Bryan

    2015-05-26

    A simple method for the functionalization of closo-borates [closo-B10 H10 ](2-) (1), [closo-1-CB9 H10 ](-) (2), [closo-B12 H12 ](2-) (3), [closo-1-CB11 H12 ](-) (4), and [3,3'-Co(1,2-C2 B9 H11 )2 ](-) (5) is described. Treatment of the anions and their derivatives with ArI(OAc)2 gave aryliodonium zwitterions, which were sufficiently stable for chromatographic purification. The reactions of these zwitterions with nucleophiles provided facile access to pyridinium, sulfonium, thiol, carbonitrile, acetoxy, and amino derivatives. The synthetic results are augmented by mechanistic considerations. PMID:25877873

  12. EPR and NMR studies of amorphous aluminum borates

    Simon, S.; Pol, A.; Reijerse, E.J.; Kentgens, A.P.M.; Moorsel, G.J.M.P. van; de Boer, E

    1994-01-01

    Amorphous aluminium borates, Al2(1–x)B2xO3 with O [less-than-or-eq]x[less-than-or-eq] 0.5, prepared from mixtures of aluminium nitrate, boric acid and glycerol, have been studied by EPR and 27Al MASNMR as a function of composition and heat-treatment temperature (Tt[less-than-or-eq] 860 °C). EPR studies showed the presence of physisorbed NO2, NO and O2 molecules, produced by decomposition reactions during the thermal treatment. The O2 molecules in the gaseous state were observed in a narrow te...

  13. Synthesis, characterisation, electrical and optical properties of copper borate compounds

    Kipcak, Azmi Seyhun; Senberber, Fatma Tugce [Department of Chemical Engineering, Faculty of Chemical and Metallurgical Engineering, Yildiz Technical University, Istanbul (Turkey); Aydin Yuksel, Sureyya [Department of Physics, Faculty of Arts and Science, Yildiz Technical University, Istanbul (Turkey); Derun, Emek Moroydor, E-mail: moroydor@gmail.com [Department of Chemical Engineering, Faculty of Chemical and Metallurgical Engineering, Yildiz Technical University, Istanbul (Turkey); Piskin, Sabriye [Department of Chemical Engineering, Faculty of Chemical and Metallurgical Engineering, Yildiz Technical University, Istanbul (Turkey)

    2015-10-15

    Highlights: • Cu(BO{sub 2}){sub 2} was synthesized at the form of with pdf number of “00-001-0472”. • Particle sizes were found between 162.72 and 56.44 nm and 195.76 and 75.73 nm at CuSNaH. • Reaction yields were 90.4 ± 0.84, 96.9 ± 0.78 and 78.9 ± 0.76% for CuST, CuSB and CuSNaH. • The resistivity of CuST, CuSB and CuSNaH are 1.10 × 10{sup 7}, 7.02 × 10{sup 6} and 8.62 × 10{sup 5} Ωm. • The optical energy gap was 3.76 eV. - Abstract: The hydrothermal synthesis of copper borate compounds [Cu(BO{sub 2}){sub 2}] was studied, and several parameters were found to affect the synthesis. Raw materials, including CuSO{sub 4}·5H{sub 2}O, Na{sub 2}B{sub 4}O{sub 7}·5H{sub 2}O, Na{sub 2}B{sub 4}O{sub 7}·10H{sub 2}O, NaOH and H{sub 3}BO{sub 3}, were used. Reaction temperatures and reaction times between 40 °C and 100 °C and 15 and 240 min, respectively, were used. The as-synthesised copper borate was analysed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The yields of the reactions were also calculated. Single-phase, nanoparticulate copper borate compounds (Cu(BO{sub 2}){sub 2}) possessing high XRD crystal scores were obtained; the reactions used to obtain these materials were highly efficient. Electrical resistivity and optical absorbance measurements were carried out on the compounds obtained from the highest yielding reactions. The results of this study showed that even using a reaction time of 15 min, copper borate formation was successfully achieved.

  14. Synthesis and characterization of cadmium doped lead–borate glasses

    A A Alemi; H Sedghi; A R Mirmohseni; V Golsanamlu

    2006-02-01

    Cadmium doped lead–borate glasses were prepared from the melts in appropriate proportions of PbO2, H3BO3 and (15–40 mol%) CdO mixture in the temperature range 700–950°C. The infrared spectra of the glasses in the range 400–4000 cm-1 show their structures. No boroxol ring formation was observed in the structure of these glasses. Furthermore, doped cadmium atoms were not seen in tetrahedral coordination. But the conversion of three-fold to four-fold coordination of boron atoms in the structure of glasses was observed.

  15. Crystal chemistry and structure refinement of five hydrated calcium borates

    Clark, J.R.; Appleman, D.E.; Christ, C.L.

    1964-01-01

    The crystal structures of the five known members of the series Ca2B6O11??xH2O (x = 1, 5, 5, 7, 9, and 13) have been refined by full-matrix least-squares techniques, yielding bond distances and angles with standard errors of less than 0??01 A?? and 0??5??, respectively. The results illustrate the crystal chemical principles that govern the structures of hydrated borate compounds. The importance of hydrogen bonding in the ferroelectric transition of colemanite is confirmed by more accurate proton assignments. ?? 1964.

  16. General and Localized Corrosion of Borated Stainless Steels

    T.E. Lister; Ronald E. Mizia; A.W. Erickson; T.L. Trowbridge; B. S. Matteson

    2008-03-01

    The Transportation, Aging and Disposal (TAD) canister-based system is being proposed to transport and store spent nuclear fuel at the Monitored Geologic Repository (MGR) located at Yucca Mountain, Nevada. The preliminary design of this system identifies borated stainless steel as the neutron absorber material that will be used to fabricate fuel basket inserts for nuclear criticality control. This paper discusses corrosion test results for verifying the performance of this material manufactured to the requirements of ASTM A887, Grade A, under the expected repository conditions.

  17. Coordination chemistry of poly(thioether)borate ligands.

    Riordan, Charles G

    2010-08-01

    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

  18. Production of zinc and copper borates in united process cycle

    Ecological technology permitting production of Zn3·B10O18·14H2O, 2ZnO·3B2O3·7H2O, 3CuO·2B2O3·nH2O·mNa2SO4 at a time in the single technological cycle was developed. Products was obtained during reaction of proper sulfates with borax in the presence of boric acid and sodium hydroxide. Mother liquor comprising saturated boric acid solution was used for the following preparation of zinc and copper borates

  19. Photoluminescence of a Te4+ center in zinc borate glass.

    Masai, Hirokazu; Yamada, Yasuhiro; Okumura, Shun; Kanemitsu, Yoshihiko; Yoko, Toshinobu

    2013-10-01

    Photoluminescent (PL) properties related to Te(4+) species in zinc borate glasses are examined. Broad emission was observed by the excitation of the PL excitation peak of Te(4+) present at the optical absorption edge. The emission intensity of Te(4+) in 5TeO(2)-50ZnO-45B(2)O(3) glass was thermally quenched in a temperature region over 100 K, suggesting that concentration quenching preferentially occurred. The lifetime of the emission was approximately 2.5 μs, which is characteristic of relaxation from the triplet excitation state of an ns(2)-type center. PMID:24081051

  20. Photo- and thermostimulated luminescence of zinc borates, activated with manganese

    Zinc borates activated with Mn2+ have effective luminescence when exciting in the vacuum ultraviolet radiation range. It is connected with excitation energy absorption by anions. The luminescence spectra represent themselves wide bands with λmax = 540 nm for Zn4O5(BO2)6 - Mn2+ and ZnB4O7 - Mn2+, 595 nm for Zn3(BO3)2 - Mn2+. The zink orthoborate luminescence in the yellow-range of the spectra is connected with disordered tetrahedral environment of an activator

  1. Optical properties of Eu3+-doped zinc borate glasses

    Photoluminescence, absorption and optical excitation spectra of undoped and Eu3+-doped binary zinc borate glasses of varied composition prepared by the melt quenching technique in air atmosphere were investigated. From photoluminescence measurements it was found that growing Eu3+ concentration leads to gradual disappearance of the broadband glass emission in the near-UV spectral range, while the red Eu3+ emission at 613 nm shows a considerable increase. This result together with excitation spectra suggests that the Eu3+ ions are excited via energy transfer from the initially excited glassy host. The glass composition strongly affects the position of the excitation maximum in the UV energy range

  2. Lithium conducting ionic liquids based on lithium borate salts

    Zygadlo-Monikowska, E.; Florjanczyk, Z.; Sluzewska, K.; Ostrowska, J.; Langwald, N.; Tomaszewska, A. [Warsaw University of Technology, Faculty of Chemistry, ul. Noakowskiego 3, 00-664 Warsaw (Poland)

    2010-09-15

    The simple reaction of trialkoxyborates with butyllithium resulted in the obtaining of new lithium borate salts: Li{l_brace}[CH{sub 3}(OCH{sub 2}CH{sub 2}){sub n}O]{sub 3}BC{sub 4}H{sub 9}{r_brace}, containing oxyethylene substituents (EO) of n=1, 2, 3 and 7. Salts of n {>=} 2 show properties of room temperature ionic liquid (RTIL) of low glass transition temperature, T{sub g} of the order from -70 to -80 C. The ionic conductivity of the salts depends on the number of EO units, the highest conductivity is shown by the salt with n = 3; in bulk its ambient temperature conductivity is 2 x 10{sup -5} S cm{sup -1} and in solution in cyclic propylene sulfite or EC/PC mixture, conductivity increases by an order of magnitude. Solid polymer electrolytes with borate salts over a wide concentration range, from 10 to 90 mol.% were obtained and characterized. Three types of polymeric matrices: poly(ethylene oxide) (PEO), poly(trimethylene carbonate) (PTMC) and two copolymers of acrylonitrile and butyl acrylate p(AN-BuA) were used in them as polymer matrices. It has been found that for systems of low salt concentration (10 mol.%) the best conducting properties were shown by solid polymer electrolytes with PEO, whereas for systems of high salt concentration, of the polymer-in-salt type, good results were achieved for PTMC as polymer matrix. (author)

  3. Spectral characterization of lithium borate glass material with neodymium ions

    There has been a significant interest in the spectroscopic properties of trivalent rare earth ions doped glasses for their potential use as industrial laser materials, fiber optics materials and wavelength converting devices. Lithium borate glasses with neodymium ions have been prepared by the melt quenching technique. Their absorption and fluorescence spectra have been measured in the range 400-2000 nm respectively. The density and refractive index have been also studied. We present spectral characterization of 71.0 B2O3 - 22.2 Li2O - 5.0 Na2O - 1.5 Al2O3 glass materials doped with different concentrations of neodymium ion. From the measured intensities of various absorption bands of these glasses, Judd-Ofelt parameters, Ωλ, have been evaluated. The bonding environment surrounding the rare earth ion has also been discussed. With the help of Ωλ parameters and luminescence data for various emission lines, radiative properties for different emission lines have been calculated and discussed. The high value of p for the 4F3/24I13/2 transition suggests that Nd3+ doped lithium borate glass specimen drawn in the form of a fiber with some suitable modifications (doping with high quality of Nd2O3) can be used as an efficient single mode fiber amplifier operating at 1.3 μm for telecommunication purposes. (author)

  4. Luminescence properties and radiation response of sodium borate glasses scintillators

    We examined basic luminescence properties and radiation response of sodium borate glass scintillators activated with Pb2+, Cu+, Ti4+, V5+, W6+ and Yb3+ ions, respectively. These glasses had more than 80% transparency for emission wavelength range, and strong absorption bands due to the charge transition of the ions were observed. In the photoluminescence spectra, all glasses demonstrated intense emission peak in visible region, which are corresponding to the ions with s2 (Pb2+), d10 (Cu+) and d0 (Ti4+, V5+, W6+) configuration. Additionally charge transfer emission was observed in Yb3+-doped glass. When 241Am 5.5 MeV alpha-ray excited the glasses, they showed weak emission intensity because of low energy transfer efficiency from host lattice to emission center. By 241Am irradiated pulse height spectra, Cu+-doped glass demonstrated the highest scintillation output in the glasses. -- Highlights: ► This study is development of new borate glass scintillators. ► The glasses showed more than 80% transparency for emission wavelength range. ► Visible emission bands were observed under photo-excitation from the glasses. ► Cu+-doped glass demonstrated the highest scintillation output in the glasses

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

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

    2013-01-01

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

  6. Third order nonlinear optical properties of bismuth zinc borate glasses

    Third order nonlinear optical characterization of bismuth zinc borate glasses are reported here using different laser pulse durations. Bismuth zinc borate glasses with compositions xBi2O3-30ZnO-(70-x) B2O3 (where x = 30, 35, 40, and 45 mol. %) have been prepared by melt quenching method. These glasses were characterized by Raman, UV-Vis absorption, and Z scan measurements. Raman and UV-Vis spectroscopic results indicate that non-bridging oxygens increase with increase of bismuth content in the glass. Nonlinear absorption and refraction behavior in the nanosecond (ns), picosecond (ps), and femtosecond (fs) time domains were studied in detail. Strong reverse saturable absorption due to dominant two-photon absorption (TPA) was observed with both ps and fs excitations. In the case of ns pulse excitations, TPA and free-carrier absorption processes contribute for the nonlinear absorption. Two-photon absorption coefficient (β) and the absorption cross section due to free carriers (σe) are estimated by theoretical fit of the open aperture Z-scan measurements and found to be dependent on the amount of bismuth oxide in the glass composition. In both ns and fs regimes the sign and magnitude of the third order nonlinearity are evaluated, and the optical limiting characteristics are also reported

  7. Third order nonlinear optical properties of bismuth zinc borate glasses

    Shanmugavelu, B.; Ravi Kanth Kumar, V. V.; Kuladeep, R.; Narayana Rao, D.

    2013-12-01

    Third order nonlinear optical characterization of bismuth zinc borate glasses are reported here using different laser pulse durations. Bismuth zinc borate glasses with compositions xBi2O3-30ZnO-(70-x) B2O3 (where x = 30, 35, 40, and 45 mol. %) have been prepared by melt quenching method. These glasses were characterized by Raman, UV-Vis absorption, and Z scan measurements. Raman and UV-Vis spectroscopic results indicate that non-bridging oxygens increase with increase of bismuth content in the glass. Nonlinear absorption and refraction behavior in the nanosecond (ns), picosecond (ps), and femtosecond (fs) time domains were studied in detail. Strong reverse saturable absorption due to dominant two-photon absorption (TPA) was observed with both ps and fs excitations. In the case of ns pulse excitations, TPA and free-carrier absorption processes contribute for the nonlinear absorption. Two-photon absorption coefficient (β) and the absorption cross section due to free carriers (σe) are estimated by theoretical fit of the open aperture Z-scan measurements and found to be dependent on the amount of bismuth oxide in the glass composition. In both ns and fs regimes the sign and magnitude of the third order nonlinearity are evaluated, and the optical limiting characteristics are also reported.

  8. Synthesis and studies on microhardness of alkali zinc borate glasses

    Subhashini,, E-mail: subhashini.p.p@gmail.com; Bhattacharya, Soumalya, E-mail: subhashini.p.p@gmail.com; Shashikala, H. D., E-mail: subhashini.p.p@gmail.com; Udayashankar, N. K., E-mail: subhashini.p.p@gmail.com [Department of Physics, National Institute of Technology Karnataka, Surathkal-575025 (India)

    2014-04-24

    The mixed alkali effect on zinc borate glasses have been reported. The glass systems of nominal composition 10Zn+xLi{sub 2}O+yNa{sub 2}O+80B{sub 2}O{sub 3} (x = y = 0, 5, 10, 15 mol%) were prepared using standard melt quenching method. The structural, physical and mechanical properties of the samples have been studied using X-ray diffraction(XRD), density measurement and Vickers hardness measurement, respectively. A consistent increase in the density was observed, which explains the role of the modifiers (Li{sub 2}O and Na{sub 2}O) in the network modification of borate structure. The molar volume is decreasing linearly with the alkali concentration, which is attributed to the conversion of tetrahedral boron (BO{sub 4/2}){sup −} into (BO{sub 3/2}){sup −}. The microhardness studies reveals the anisotropy nature of the material. It further confirms that the samples belong to hard glass category.

  9. Third order nonlinear optical properties of bismuth zinc borate glasses

    Shanmugavelu, B.; Ravi Kanth Kumar, V. V., E-mail: ravi.phy@pondiuni.edu.in [Department of Physics, Pondicherry University, Puducherry 605 014 (India); Kuladeep, R.; Narayana Rao, D. [School of Physics, University of Hyderabad, Hyderabad 500046, Andhra Pradesh (India)

    2013-12-28

    Third order nonlinear optical characterization of bismuth zinc borate glasses are reported here using different laser pulse durations. Bismuth zinc borate glasses with compositions xBi{sub 2}O{sub 3}-30ZnO-(70-x) B{sub 2}O{sub 3} (where x = 30, 35, 40, and 45 mol. %) have been prepared by melt quenching method. These glasses were characterized by Raman, UV-Vis absorption, and Z scan measurements. Raman and UV-Vis spectroscopic results indicate that non-bridging oxygens increase with increase of bismuth content in the glass. Nonlinear absorption and refraction behavior in the nanosecond (ns), picosecond (ps), and femtosecond (fs) time domains were studied in detail. Strong reverse saturable absorption due to dominant two-photon absorption (TPA) was observed with both ps and fs excitations. In the case of ns pulse excitations, TPA and free-carrier absorption processes contribute for the nonlinear absorption. Two-photon absorption coefficient (β) and the absorption cross section due to free carriers (σ{sub e}) are estimated by theoretical fit of the open aperture Z-scan measurements and found to be dependent on the amount of bismuth oxide in the glass composition. In both ns and fs regimes the sign and magnitude of the third order nonlinearity are evaluated, and the optical limiting characteristics are also reported.

  10. Optimization of the boration and dilution process due to power variations

    During power variations in a PWR reactor, Xenon and Samarium concentration changes occurs, carrying reactivity changes that must be compensated to keep constant the reactor criticality. That compensation is made by the addition of boron (Boration) or water (Dilution) into the core coolant. Both processes have significant costs, which is a motivation to make a power variation programming taking care to Boration and Dilution processes. In this work we present a method to optimize Boron utilization or borated water storage by choosing the best power reactor variation. (author)

  11. A facile electrodeposition of hydroxyapatite onto borate passivated surgical grade stainless steel

    Highlights: → Successful deposition of hydroxyapatite on 316L SS by a facile electrolytic Method. → Improvement of bio-resistivity of the alloy by increasing the time of borate Passivation. → Evolution of stable, bio-resistive hydroxyapatite coatings on borate passivated 316L SS. - Abstract: This paper reports a successful electrodeposition method for coating hydroxyapatite (HAP) onto surgical grade stainless steel (SS). Pure HAP coatings could be achieved at -1400 mV vs SCE and the coating resistivity was assessed by potentiodynamic polarization and impedance techniques which showed that HAP coatings deposited onto the borate passivated-SS specimens possess maximum bioresistivity in Ringer's solution. The coatings were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Atomic force microscopy (AFM). The results have showed that the borate passivation followed by HAP coating performed on 316L SS could enhance the longevity of the alloy in Ringer's solution.

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

    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

  13. Influence of sodium borate on the early age hydration of calcium sulfoaluminate cement

    Calcium sulfoaluminate (CSA) cements are potential candidates for the conditioning of radioactive wastes with high sodium borate concentrations. This work thus investigates early age hydration of two CSA cements with different gypsum contents (0 to 20%) as a function of the mixing solution composition (borate and NaOH concentrations). Gypsum plays a key role in controlling the reactivity of cement. When the mixing solution is pure water, increasing the gypsum concentration accelerates cement hydration. However, the reverse is observed when the mixing solution contains sodium borate. Until gypsum exhaustion, the pore solution pH remains constant at ~ 10.8, and a poorly crystallized borate compound (ulexite) precipitates. A correlation is established between this transient precipitation and the hydration delay. Decreasing the gypsum content in the binder, or increasing the sodium content in the mixing solution, are two ways of reducing the stability of ulexite, thus decreasing the hydration delay

  14. Influence of sodium borate on the early age hydration of calcium sulfoaluminate cement

    Champenois, Jean-Baptiste; Dhoury, Mélanie [CEA, DEN, DTCD, SPDE, F-30207 Bagnols-sur-Cèze Cedex (France); Cau Dit Coumes, Céline, E-mail: celine.cau-dit-coumes@cea.fr [CEA, DEN, DTCD, SPDE, F-30207 Bagnols-sur-Cèze Cedex (France); Mercier, Cyrille [LMCPA, Université de Valenciennes et du Hainaut Cambrésis, 59600 Maubeuge (France); Revel, Bertrand [Centre Commun de Mesure RMN, Université Lille1 Sciences Technologies, Cité Scientifique, 59655 Villeneuve d' Ascq Cedex (France); Le Bescop, Patrick [CEA, DEN, DPC, SECR, F-91192 Gif-sur-Yvette (France); Damidot, Denis [Ecole des Mines de Douai, LGCgE-GCE, 59508 Douai (France)

    2015-04-15

    Calcium sulfoaluminate (CSA) cements are potential candidates for the conditioning of radioactive wastes with high sodium borate concentrations. This work thus investigates early age hydration of two CSA cements with different gypsum contents (0 to 20%) as a function of the mixing solution composition (borate and NaOH concentrations). Gypsum plays a key role in controlling the reactivity of cement. When the mixing solution is pure water, increasing the gypsum concentration accelerates cement hydration. However, the reverse is observed when the mixing solution contains sodium borate. Until gypsum exhaustion, the pore solution pH remains constant at ~ 10.8, and a poorly crystallized borate compound (ulexite) precipitates. A correlation is established between this transient precipitation and the hydration delay. Decreasing the gypsum content in the binder, or increasing the sodium content in the mixing solution, are two ways of reducing the stability of ulexite, thus decreasing the hydration delay.

  15. Styrylquinolinium borates as donor-acceptor initiators for sensitized photopolymerization of TMPTA

    Jedrzejewska, Beata, E-mail: beata@utp.edu.pl [University of Technology and Life Sciences, Faculty of Chemical Technology and Engineering, Seminaryjna 3, 85-326 Bydgoszcz (Poland); Marcin, Tur; Paczkowski, Jerzy [University of Technology and Life Sciences, Faculty of Chemical Technology and Engineering, Seminaryjna 3, 85-326 Bydgoszcz (Poland)

    2009-10-15

    Several photoredox pairs containing mono- and bicationic hemicyanine dyes have been evaluated as photoinitiators for free radical polymerization induced with an argon-ion laser irradiation. The tested photoredox couples are the pairs composed of the hemicyanine dye cations acting as electron acceptors and n-butyltriphenyl borate anions being the electron donors. The photoinitiating abilities of the series of monochromophoric stilbazolium borates, 4-(p-N,N-dialkylaminostyryl)quinolinium n-butyltriphenylborate, were compared to the photochemistry of structurally related, bicationic styrylquinolinium borates. The obtained results clearly documented that the dicationic photoinitiators exhibit a marked increase in the photoinitiation ability compared to the initiators consisting of a single charged hemicyanine dye. Our studies revealed also that the rate of photopolymerization depends on {Delta}G{sub el} of electron transfer between borate anion and styrylquinolinium cation. The relationship between the rate of polymerization and the free energy of activation shows the dependence predicted by the classical theory of electron transfer.

  16. Styrylquinolinium borates as donor-acceptor initiators for sensitized photopolymerization of TMPTA

    Several photoredox pairs containing mono- and bicationic hemicyanine dyes have been evaluated as photoinitiators for free radical polymerization induced with an argon-ion laser irradiation. The tested photoredox couples are the pairs composed of the hemicyanine dye cations acting as electron acceptors and n-butyltriphenyl borate anions being the electron donors. The photoinitiating abilities of the series of monochromophoric stilbazolium borates, 4-(p-N,N-dialkylaminostyryl)quinolinium n-butyltriphenylborate, were compared to the photochemistry of structurally related, bicationic styrylquinolinium borates. The obtained results clearly documented that the dicationic photoinitiators exhibit a marked increase in the photoinitiation ability compared to the initiators consisting of a single charged hemicyanine dye. Our studies revealed also that the rate of photopolymerization depends on ΔGel of electron transfer between borate anion and styrylquinolinium cation. The relationship between the rate of polymerization and the free energy of activation shows the dependence predicted by the classical theory of electron transfer.

  17. Current-voltage characteristics of MDM and MDSCM structures on basis of lithium borates

    Adamiv, V. T.; Burak, Ya. V.; Say, I. S.; Teslyuk, I. M.; Turko, B. S.; Panasyuk, M. R.

    2012-01-01

    The results of investigations of current-voltage characteristics for metal dielectric-metal and metaldielectric- semiconductor-metal structures, where crystalline and glass lithium borates used as dielectrics, are presented.

  18. Borate-fructose complex: A novel mediator for laccase and its new function for fructose determination.

    Cheng, Chih-Yu; Liao, Chia-I; Lin, Shuen-Fuh

    2015-10-01

    Laccase and borate-fructose complex were investigated by coincidence in a solid-state fermentation of Edenia sp. TS-76 under fructose oxidase screening. Laccase was purified to homogeneity with a 34-fold purification and 32% yield. Fructose had no significant effect on laccase activity, whereas borate reduced laccase activity by 60-90%; conversely, the borate-fructose complex increased laccase activity by nearly fourfold at pH 7.5. The complex caused a shift in the optimal pH for laccase from 5.0 to 7.5 and served as a highly efficient mediator. Borate complexed with fructose provides an alternative, time-saving, and specific method for serum fructose determination. PMID:26335748

  19. Superparamagnetic resonance of annealed iron-containing borate glass

    A lithium borate glass containing a small amount of iron oxide is studied by electron magnetic resonance at room temperature after repeated annealing steps between 460 and 670 deg. C. As the anneal temperature increases, the gef=4.3 sharp line characteristic of isolated iron ions decreases in intensity and finally disappears. Simultaneously, a narrow line emerges at gef approx. 2.0, superposed with a broader one, the narrow and the broader components predominating respectively after annealing at lower and at higher temperatures. Computer simulations of spectra have been carried out, based on a model of resonance of ferromagnetic single-domain nanoparticles randomly dispersed in the devitrified glass (superparamagnetic resonance). As the anneal temperature increases, the most probable particle diameter obtained assuming a log-normal distribution of diameters increases from 2.9 to 4.7 nm showing a saturation at higher anneal temperatures, whereas the relative number of larger particles grows continuously. (author)

  20. Structural investigation of Zn doped sodium bismuth borate glasses

    Bhatia, V.; Kumar, D.; Singh, D.; Singh, S. P.

    2016-05-01

    A series of Bismuth Borate Oxide Glass samples with composition x(ZnO):(15-x)Na2O:15Bi2O3:70B2O3 (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 BO3 & BO4 structural units) have been observed.

  1. Elastic properties of Li+ doped lead zinc borate glasses

    Rajaramakrishna, R.; Lakshmikantha, R.; Anavekar, R. V.

    2014-04-01

    Glasses in the system 0.25PbO-(0.25-x) ZnO-0.5B2O3-xLi2O have been prepared by the melt quenching technique. Elastic properties, DSC studies have been employed to study the role of Li2O in the present glass system. Elastic properties and Debye temperature have been determined using pulsed echo ultrasonic interferometer operating at 10MHz. Sound velocities Vl, Vt and elastic moduli decrease up to 5 mol% and then gradually increase with increase in Li2O concentration. Debye temperature and the glass transition temperature decreases with increase in Li2O. Densities remains almost constant up to 15 mol% Li2O concentration and increases monotonically while the molar volume decreases with the increase of Li2O concentration. The results are discussed in view of the borate structural network and dual role of Zn and Pb in these glasses.

  2. Thermal, structural and electrical studies of bismuth zinc borate glasses

    Shanmugavelu, B.; Ravi Kanth Kumar, V. V.

    2013-06-01

    Bismuth Zinc Borate glasses with compositions xBi2O3-30ZnO-(70 - x)B2O3 (where x = 30, 35, 40 and 45 mol %) have been prepared by melt quenching method. These glasses were characterized by X-ray diffraction (XRD), Differential Thermal Analysis (DTA), Fourier Transform Infrared Spectrometer (FTIR) and Broad Band Dielectric Spectrometer (BDS). DTA and FTIR analysis reveals that Non-Bridging Oxygens (NBOs) increase with increase of bismuth content in the glass. Electrical data have been analyzed in the framework of impedance and modulus formalisms. The activation energy for dc conductivity decreases with increase of bismuth concentration. The imaginary part of modulus spectra has been fitted to non-exponential Kohlrausch-Williams-Watts (KWW) function and the value of the stretched exponent (β) is found to be almost independent of temperature but slightly dependent on composition.

  3. Process for the storage of borate containing radioactive wastes by vitrification

    For storage of radioactive waste by vitrification the radioactive waste concentrates from borate-containing liquids are mixed with glass-forming aggregates. The borates make up a major part of the glass product. A glass product with good chemical and physical properties for storage is produced by heating to produce a glass-forming melt. Lead oxides and silicates in particular are considered suitable aggregate materials. (orig.)

  4. Infrared Spectroscopy and Raman Scattering Studies On the Structure of Lithium Borate Glass

    Infrared Spectroscopic investigation and Raman Scattering study of lithium borate glasses in the system xLi20. (1-x) B203 for various values of have been performed in order to understand the influence of Li20 on the network structure of lithium borate glass. The IR spectra show clearly the disappearance of boroxol rings and the formation, in a first step, of tetraborate groups and later of diborate groups as the oxide content increases

  5. Chiral selection in the formation of borates from racemic binaphthols and related diols

    Raskatov, Jevgenij A.; Brown, John M.; Amber L. Thompson

    2011-01-01

    A series of racemic or stereochemically labile chiral borate anions based on the 2,2′-biphenol motif was investigated. All borates were homochiral in the solid state, although in some cases the heterochiral diastereomers were computed to be thermodynamically preferred (DFT). The crystallographic preference for the homochiral diastereomer was attributed to its lower bulk, higher molecular symmetry, and the therewith associated better packing ability.

  6. Borates in the Argentine Puna: A New Application of Magnetic Separation

    Flores, H. R.; Villagran, P.

    1992-01-01

    Large, highly marketable deposits of borate are situated in the north-western Argentina. The exploitation of these deposits started in the beginning of this century. The exploitation and industrialization of some of these deposits during the 1980s turned the region into an important trading centre for export of raw borates and of boric acid. Technical specifications, as regards the iron content in those products, are very rigorous, particularly if they are used in manufacture of high-quality ...

  7. Interaction of lead-borate glass with aluminium and iron-nickel alloys

    Interaction of aluminium (AMG-6) and iron-nickel (47ND) alloys with lead-borate glass of PbO-73, BeO3-12, ZnO-10, Al2O3-3, SiO2-2 (mas. %) composition is investigated. It is determined that components of both soldered alloys interact actively with lead-borate glass melt that allows to obtain strong cohesion of glass with AMG-6 and 47ND metal alloys

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

    Undoped and dysprosium doped lithium borate glass system with empirical formula (70–x) B2O3–30 Li2O–(x) Dy2O3 (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% Dy2O3 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

  9. Separation of bivalent anti-T cell immunotoxin from Pichia pastoris glycoproteins by borate anion exchange.

    Woo, Jung Hee; Neville, David M

    2003-08-01

    A major problem encountered in the large-scale purification of the bivalent anti-T cell immunotoxin, A-dmDT390-bisFv(G4S), from Pichia pastoris supernatants was the presence of host glycoproteins exhibiting similar charge, size, and hydrophobicity characteristics. We overcame this problem by employing borate anion exchange chromatography. The borate anion has an affinity for carbohydrates and imparts negative charges to these structures. We found that at a concentration of sodium borate between 50 and 100 mM, the nonglycosylated immunotoxin did not bind to Poros 50 HQ anion exchanger resin, but glycoproteins, including aggregates related to the immunotoxin, did. By using this property of the immunotoxin in the presence of sodium borate, we successfully developed a 3-step purification procedure: (i) Butyl-650M hydrophobic interaction chromatography, (ii) Poros 50 HQ anion exchange chromatography in the presence of borate, and (iii) HiTrap Q anion exchange chromatography. The final preparation exhibited a purity of greater than 98% and a yield of greater than 50% from the supernatant. Previously, boronic acid resins have been used to separate glycoproteins from proteins. However, combining borate anion with conventional anion exchange resins accomplishes the separation of the immunotoxin from glycoproteins and eliminates the need to evaluate nonstandard resins with respect to good manufacturing practice guidelines. PMID:12951782

  10. Spectrophotometric determination of boron in complex matrices by isothermal distillation of borate ester into curcumin

    In situ distillation of borate ester into the curcumin solution has been developed for the spectrophotometric determination of boron in a variety of complex matrixes. A polypropylene vessel containing the sample solution was placed inside a vessel (PP) containing 10 ml of curcumin solution and the distillation was carried out at room temperature/on a water bath. The borate ester collected in to the curcumin solution was evaporated to dryness on the water bath, taken in acetone and the absorbance was measured at 550 nm. In situ distillation of borate ester directly into the chromogenic reagent eliminates tedious sample treatment (before and/or after borate separation), use of methanol, complicated quartz set up, possible loss of boron and reduces the analysis time significantly. In situ dehydration of sample solution by ethanolic vapour in the absence of dehydrating acid prevents the formation of fluoborate and co-distillation of potential anionic interferents (nitrate and fluoride). This developed method has been applied for the determination of traces of boric acid in boron powder by the distillation of methyl borate at room temperature. For other matrixes (water, uranium oxide, uranyl nitrate, fluoride salt, etc.) distillation of ethyl borate was carried out on the water bath. LOD (3σ) was 5 ng g-1 for water and 30 ng g-1 for solid samples

  11. Synthesis and Characterization of Zinc Borate Nanowhiskers and Their Inflaming Retarding Effect in Polystyrene

    Pingqiang Gao

    2015-01-01

    Full Text Available Zinc borate nanowhiskers 4ZnO·B2O3·H2O were in situ successfully synthesized via one-step precipitation reaction. A set of experiments was performed to evaluate the influence of reaction temperature. Increasing the temperature up to 70°C led to the high purity of zinc borate nanowhiskers with a monoclinic crystal structure measuring 50 nm to 100 nm in diameter and approximately 1 µm in length. However, higher temperature decreases the crystallization due to the emergence of other styles of zinc borate. Flame-resistant nanocomposites of polystyrene and zinc borate nanowhiskers were also successfully synthesized. The samples were investigated by XRD, FESEM, FTIR, and TG. The mechanical properties of the composites were also tested. The incorporation of zinc borate nanowhiskers improved the thermal and mechanical properties for polystyrene. FESEM images show that zinc borate nanowhiskers increased the smoothness of composites. The composites presented good responsive behavior in relation to LOI (limiting oxygen index allowing them to be suitable for green flame retardants.

  12. Thermo- and radioluminescence of undoped and Dy-doped strontium borates prepared by sol-gel method

    Borates have shown to be efficient materials to be employed for ionizing radiation detection given their tissue-equivalent characteristics. Usually, the efficiency of these compounds is largely dependent on the preparation methods and conditions. In this work nominally pure and Dy-doped strontium borates have been prepared by sol-gel method. The thermoluminescence and radioluminescence of the resulting borates have been investigated and correlated to their structural characteristics.

  13. Synthesis and luminescence of Tb3+ doped lithium borate (LiBO2)

    We report that terbium doped lithium borate phosphors were synthesized by conventional solid state reaction method for the first time. X-ray diffraction (XRD) analysis, radioluminescence (RL) and thermally stimulated luminescence (TSL) were used to investigate structural and luminescence properties of terbium doped lithium borate phosphors. XRD patterns confirm that the lithium borate phosphors sintered at 1200 °C exhibit monoclinic structure. RL spectrum revealed that terbium ions are present in trivalent oxidation states. RL measurements shows that the series of emission state 5D4→7F6, 5D4→7F5, 5D4→7F4 and 5D4→7F3, corresponding to the typical 4f→4f infra-configuration forbidden transitions of Tb3+, are appeared and major emission peak is around at 541 nm. The TSL kinetic parameters of a newly prepared terbium doped lithium borate phosphor have been calculated. The LiBO2:Tb3+ exhibits two TSL glow curves at around 90 and 155 °C. The kinetic parameters, namely activation energy (trap depth) and frequency factor (s) associated with the main glow peak (155 °C) of the material were determined using peak shape (PS) and various heating rates (VHR) methods. -- Highlights: ► We report that terbium doped lithium borate phosphors were synthesized by conventional solid state reaction method for the first time. ► XRD analysis, RL and TSL techniques were used to investigate structural and luminescence properties of terbium doped lithium borate phosphors. ► The TSL kinetic parameters of synthesized terbium doped lithium borate phosphor have been calculated using PS and VHR methods

  14. Effect of Nd dopant ions on borate glass structure

    A set of four borate glasses containing varying concentrations of neodymium were prepared and studied by neutron diffraction. The oxide 11B2O3 derived from boric acid was the host matrix with Nd2O3 varying from 10 to 25 molar percent in the glass. Earlier, different rare-earth oxides in a phosphate host were studied, but the effect of increasing levels of the dopant is less well known. The high Q diffractometer at Dhruva Reactor was used for the neutron diffraction measurements on the glasses using 0.783 Å incident neutrons. The instrument has a fixed arc of linear position sensitive detectors covering the Q range up to 15 Å-1. Experimental corrections and normalization were performed before Fourier inversion to obtain the total correlation functions, the radial distributions and the coordination numbers. The nearest neighbour correlation at 1.4 Å in T(r) relates to all the B-O distances - both of the BO3 units and the BO4 tetrahedra. MCGR calculations were also performed on these data and clearly demonstrated a shoulder at about 1.86 Å which could be due to the Al-O correlation (Al2O3 contaminant from the alumina crucibles). The second major feature in T(r) at about 2.4 Å is known to be due to the Nd-O and the O-O correlations taken together. It is noted that the coordination number of oxygen atoms around the rare-earth ion increases from the 10 % through the 15% to the 20% Nd2O3 samples. In order to reconcile this observation with a model of a continuous random network of B-O bonds of the glass former, it is proposed that the borate network may be getting distorted in the vicinity of the Nd ions such that the B-O bonds of both basic units of the host matrix are elongated to 1.86 Å. The latter oxygen atoms would add to the coordination number of the R-O correlations without the requirement of additional bonding between them and the Nd ion. (author)

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

    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

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

    In this thesis, the specific conductivity of ion-sputtered lithium borate thin films is studied. To this end, lithium borate glasses of the composition yLi2O.(1-y)B2O3 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-1cm-1 and 2.5 x 10-6 Ω-1cm-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 'Concept of

  17. Researches on the electrolysis of metal oxides dissolved in boric anhydride or in melt borates. New methods of preparation of amorphous boron, borides and some metals

    This research thesis reports the investigation of the electrolysis of alkaline borates, alkaline earth borates and magnesium borate, and the investigation of mixtures containing a metal oxide dissolved in a bath formed by a tetraborate and a fluoride. The author more particularly studies the chemical products separated at the cathode level, i.e. boron (more or less pure), borates and other metals (zinc, tungsten, molybdenum)

  18. Spray drying test of simulated borated waste solutions

    Performance and the effecting factors of spray drying of simulated borated waste solutions is studied for three contaeting methods between the atomized beads and the heated air, in which boron concentration is around 21000 ppm. The contacting modes are centrifugal atomizing co-current flow, pneumatic atomizing co-current flow and mixed flow. The results show that a free-flowing product in all these tests when the temperature of the solutions is between 62 degree C and 64 degree C, the inlet temperature of the spray drying chamber is between 210 degree C and 220 degree C, the temperature of the outlet of the spray drying chamber is between 110 and 120 degree C, the flow rate of the pressure air is 8.0 m3/h, the rotational speed of the centrifugal atomizer is 73.0 m/s. The diameters of the powder product which account for 95% of the feed range from 0.356 mm to 0.061 mm. The production capacity and water content in the powder increase in the order of pneumatic atomizing co-current flow, mixed flow and centrifugal atomizing co-current flow. The volume reduction coeffecient of spray drying is in the ranged of 0.22 and 0.27. (authors)

  19. Recent development of nonlinear optical borate crystals for UV generation

    Mori, Y.; Yap, Y. K.; Kamimura, T.; Yoshimura, M.; Sasaki, T.

    2002-02-01

    Recent development of high-power solid-state UV radiation by nonlinear optical (NLO) borate crystals is reviewed. The performance of such UV light sources has rapidly improved in the past five years because of the superior NLO properties of CsLiB 6O 10 (CLBO) crystals. The performance of such UV light sources also depends on the reliability of the NLO crystals. The relation between the bulk laser-induced damage threshold (LIDT), dislocation density and UV absorption of CsLiB 6O 10 (CLBO) was investigated. A newly developed synthesis process allows the growth of CLBO crystals with LIDT 2.5-fold higher than those grown by the conventional top-seeded solution growth (TSSG) technique. High-quality CLBO possesses lower dislocation density and smaller absorption of UV light ( λ=266 nm) than conventional CLBO. Reduction of the dislocation density can suppress absorption of UV light that helps to enhance the resistance of CLBO to laser-induced damages, to alleviate thermal dephasing during high-power generation of UV light and thus strengthen the reliability of CLBO for UV light generation.

  20. A comparison of HLW-glass and PWR-borate waste glass

    Luo, Shanggeng; Sheng, Jiawei; Tang, Baolong

    2001-09-01

    Glass can incorporate a wide variety of wastes ranging from high level wastes (HLW) to low and intermediate level wastes (LILW). A comparison of HLW-Glass and PWR-borate waste glass is given in this paper. The HLW glass formulation named GC-12/9B and 90-19/U can incorporate 16-20 wt% HLW at 1100°C or 1150°C. The borate waste glass named SL-1 can incorporate 45 wt% borate waste generated from PWR. Their physical properties, characteristic temperatures, chemical durability and leach behavior are summarized here. The comparison indicates: the PWR-glass SL-1 can incorporate up to 45 wt% waste oxides at lower melting temperature (1000°C) in agreement with minimum additive waste stabilization (MAWS) approach; owing to the PWR-borate glass contain less Si and more B and Na, its mass loss is higher than HWR-glass; both HLW-glass and PWR-borate glass have favorable chemical durability and the same leaching phenomena, i.e., Na is mostly depleted, but Ca, Mg, Al and Ti are enriched in the leached surface layer.

  1. Cement matrix for immobilisation of spent anionic resins in borate form arising from nuclear power plants

    In water cooled reactors boron is added as boric acid to control nuclear reactor power levels. The boric acid concentration in coolant/moderator water, is controlled by using strongly basic anionic resins in borate (H2BO3-) form. The spent anionic resins in borate form contain 131Iodine, 99Technitium and 137Cesium activities. Direct immobilisation of anionic resins in borate form in Ordinary Portland Cement (OPC) and Slag Cement was investigated using vermiculite, bentonite, calcium oxide and silica as admixtures. The cumulative fraction of 137Cesium leached and 137Cesium leach rate for slag cement matrix were 0.029 and 0.00064 g.cm2.d-1 respectively for 95 days of leaching. The volume reduction factor achieved by direct immobilisation of anionic resins in borate form was 0.48. Immobilisation of pyrolysis residues from these resins in OPC matrix was also studied. Leaching of matrix blocks was carried out for 180 days in DM water to optimise the matrix formulation. The cumulative fraction of 137Cesium leached and 137Cesium leach rate were 0.076 and 0.00054 respectively for 180 days leaching. The volume reduction factor achieved by immobilisation of pyrolysis residues was 2.4. OPC is non compatible to cationic resins loaded with alkali in absence of specific admixtures. Hence cationic resins loaded with alkali and anionic resins in borate form can not be immobilised together. (author)

  2. Revealing growth defects in non-linear borate single crystals by chemical etching

    Péter, Á.; Polgár, K.; Beregi, E.

    2000-01-01

    Inorganic cyclic borates such as β-BaB 2O 4 (BBO), LiB 3O 5 (LBO), CsLiB 6O 10 (CLBO) and Li 2B 4O 7 (LTB) are excellent non-linear optical (NLO) materials, particularly in the ultraviolet region. Another type of borate is YAl 3(BO 3) 4 (YAB) which is utilized as a laser host and for self-frequency doubling. Growth imperfections causing scattering and absorption of laser beams affect the performance and the use of borate single crystals. Defects, like inclusions, twins, grain boundaries and dislocations form readily in crystals grown by both the high temperature top-seeded solution growth (HTTSSG) method (BBO, LBO, YAB) and the Czochralski technique (CLBO, LTB). Chemical etching methods have been developed on various planes of the different borate crystals, in order to reveal the nature and the distribution of these defects. These methods have successfully been used to characterize NLO borate crystals. The origins of lattice defect formation are discussed in terms of the growth parameters.

  3. A comparison of HLW-glass and PWR-borate waste glass

    Glass can incorporate a wide variety of wastes ranging from high level wastes (HLW) to low and intermediate level wastes (LILW). A comparison of HLW-Glass and PWR-borate waste glass is given in this paper. The HLW glass formulation named GC-12/9B and 90-19/U can incorporate 16-20 wt% HLW at 1100 deg. C or 1150 deg. C. The borate waste glass named SL-1 can incorporate 45 wt% borate waste generated from PWR. Their physical properties, characteristic temperatures, chemical durability and leach behavior are summarized here. The comparison indicates: the PWR-glass SL-1 can incorporate up to 45 wt% waste oxides at lower melting temperature (1000 deg. C) in agreement with minimum additive waste stabilization (MAWS) approach; owing to the PWR-borate glass contain less Si and more B and Na, its mass loss is higher than HWR-glass; both HLW-glass and PWR-borate glass have favorable chemical durability and the same leaching phenomena, i.e., Na is mostly depleted, but Ca, Mg, Al and Ti are enriched in the leached surface layer

  4. A new nanosensor composed of laminated samarium borate and immobilized laccase for phenol determination

    2014-01-01

    A new nanosensor composed of laminated samarium borate and immobilized laccase was developed for phenol determination. The laminated samarium borate was synthesized by a mild solid-state-hydrothermal (S-S-H) method without any surfactant or Template. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) were used to characterize the samples. The morphology of the as-prepared materials was characterized by SEM, which shows that laminated samarium borate are uniform nanosheets with a layer-by-layer self-assembled single-crystal structure. These laminated samarium borate have typical diameters of 3 ~ 5 μm and the thickness of each layer is in the range of 10 ~ 80 nm. And then, these SmBO3 multilayers were used to immobilize the laccase. The proposed nanosensor composed of laminated samarium borate and immobilized laccase was successfully developed for phenol determination. Cyclic voltammetry were used to study the nanosensor. The proposed nanosensor displayed high sensitivity toward phenolic compounds. The linearity of the nanosensor for the detection of hydroquinone was obtained from 1 to 50 μM with a detection limit of 3 × 10-7 M (based on the S/N = 3). PMID:24528570

  5. Effect of modifying agents on the hydrophobicity and yield of zinc borate synthesized by zinc oxide

    Acarali, Nil Baran; Bardakci, Melek; Tugrul, Nurcan; Derun, Emek Moroydor; Piskin, Sabriye

    2013-06-01

    The aim of this study was to synthesize zinc borate using zinc oxide, reference boric acid, and reference zinc borate (reference ZB) as the seed, and to investigate the effects of modifying agents and reaction parameters on the hydrophobicity and yield, respectively. The reaction parameters include reaction time (1-5 h), reactant ratio (H3BO3/ZnO by mass: 2-5), seed ratio (seed crystal/(H3BO3+ZnO) by mass: 0-2wt%), reaction temperature (50-120°C), cooling temperature (10-80°C), and stirring rate (400-700 r/min); the modifying agents involve propylene glycol (PG, 0-6wt%), kerosene (1wt%-6wt%), and oleic acid (OA, 1wt%-6wt%) with solvents (isopropyl alcohol (IPA), ethanol, and methanol). The results of reaction yield obtained from either magnetically or mechanically stirred systems were compared. Zinc borate produced was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and contact angle tests to identify the hydrophobicity. In conclusion, zinc borate is synthesized successfully under the optimized reaction conditions, and the different modifying agents with various solvents affect the hydrophobicity of zinc borate.

  6. Synthesis of hydrophobic zinc borate nanoflakes and its effect on flame retardant properties of polyethylene

    Zinc borate (2ZnO.3B2O3.3.5H2O) has relatively high dehydration on-set temperature which property permits processing in a wide range of polymer system. But zinc borate particles are hardly dispersed in a polymer matrix so that they prevent their using in industry. To address this problem, we synthesized hydrophobic zinc borate (2ZnO.3B2O3.3.5H2O) nanoflakes by employing solid-liquid reaction of zinc oxide (ZnO) and boric acid (H3BO3) in the presence of oleic acid. This method does not bring pollution. By conducting morphological and microscopic analyses, we found that this compound displayed nanoflake morphology with particle size of around 100-200 nm, thickness less than 100 nm and there were uniform mesopores with the diameter about 10 nm within the particles. Furthermore, our products had an effect on flame retardant of polyethylene, especially when the zinc borate was modified by oleic acid. - Graphical abstract: The contact angle of hydrophobic zinc borate nanoflakes is 129.02 deg. with added 2.0 wt% of oleic acid.

  7. 77 FR 74883 - Aging Management of Stainless Steel Structures and Components in Treated Borated Water; Revision 1

    2012-12-18

    ... Treated Borated Water,'' in the Federal Register on May 11, 2012 (77 FR 27815). As issued, LR-ISG-2011-01... COMMISSION Aging Management of Stainless Steel Structures and Components in Treated Borated Water; Revision 1..., 2012 (77 FR 27815). Revision 1 of this document corrects the identification numbers for...

  8. Growth and evaluation of nonlinear optical crystals for laser applications: Lithium borate, barium borate and silver gallium selenide

    Feigelson, Robert S.; Route, Roger K.

    1994-12-01

    This report summarizes a four year program on the development of high efficiency nonlinear optical materials. Major achievements were the development of effective top-seeded solution growth techniques for beta-barium borate (BBO) and lithium triborate (LBO). BBO crystals were also grown for the first time in the US by the direct melt growth technique, a metastable method that leads to significantly higher growth rates than the commercial solution-growth technique. High quality crystals were made available for optical property determinations and nonlinear optical device development at government and commercial laboratories. Additional accomplishments involved development of an optimum heat-treatment technology for eliminating optical scattering centers from as-grown crystals of silver gallium selenide. Cooperative programs were carried out with NRL to quantify the effects of intrinsic and extrinsic defects on residual absorption. It was discovered that silver gallium selenide and silver gallium sulfide crystals grown from silver-rich solutions are free of anomolous absorption in the 2 micron waveband which is currently the major problem limiting generation of high intensity, tunable 3-5 micron radiation by OPO methods using these materials. A new nonlinear optical material, (La,Gd)Sc3(BO3)4 has been identified for future study.

  9. Luminescent properties of Eu3+-activated lithium rare earth borates and oxyborates

    The luminescence characteristics of Eu3+ in the borates Li6Y(BO3)3 and Li3La2(BO3)3 and the recently discovered oxyborates LiLa2O2BO3, LiLn6O5(BO3)3 (Ln=Y,Gd) and Li2Lu5O4(BO3)3 have been investigated and compared to those in the borates LnBO3 (Ln=La,Y) and the oxyborates ''Ln3BO6'' (Ln=La,Gd). The probability of electric dipole f-f transitions is generally markedly higher in oxyborates than in borates. This is ascribed to the highly anisotropic environment of rare earth ions and the low position of the charge transfer states. Consequently, the Eu3+-activated oxyborates are characterized by a deeper red emission and faster decay

  10. Vibrational spectroscopy of the borate mineral kotoite Mg₃(BO₃)₂.

    Frost, Ray L; Xi, Yunfei

    2013-02-15

    Vibrational spectroscopy has been used to assess the structure of kotoite a borate mineral of magnesium which is isostructural with jimboite. The mineral is orthorhombic with point group: 2/m 2/m 2/m. The mineral has the potential as a new memory insulator material. The mineral has been characterised by a combination of Raman and infrared spectroscopy. The Raman spectrum is dominated by a very intense band at 835 cm(-1), assigned to the symmetric stretching mode of tetrahedral boron. Raman bands at 919, 985 and 1015 cm(-1) are attributed to the antisymmetric stretching modes of tetrahedral boron. Kotoite is strictly an hydrous borate mineral. An intense Raman band observed at 3559 cm(-1) is attributed to the stretching vibration of hydroxyl units, more likely to be associated with the borate mineral hydroxyborate. The lack of observation of water bending modes proves the absence of water in the kotoite structure. PMID:23257343

  11. Synthesis of surface acidity of amorphous fluorine-containing aluminium borates

    A series of fluorine-containing aluminium borate samples with Al2O3/B2O3 = 3 and HF/B2O3 = 0.05-0.5 molar ratios has been synthesized by an impregnation method using NH4F. The materials obtained are amorphous up to 840-1130 K. Their thermal transformations were investigated by DTA and MSA. There are Lewis and Broensted acid sites present in these samples. The very strong Lewis sites due to formation of trigonal B3+, bonded with F- on the surface of fluorine-containing aluminium borates. Dehydration of isopropyl alcohol was used as a probe reaction to measure the acidity. The results of measurements have shown that these materials were more acidic and catalytically active than the starting aluminium borate. (author)

  12. Aminoguanidinium closo-borates and their reactions with copper(2) salts in aqueous solutions

    Amino guanidine hexa-, deca- and dodecaborates of the (AguH)2BnHn · xH2O, where Agu - (CN4H6); n = 6, 10, 12; x = 1, 2, composition were synthesized and defined by means of element, magnetic susceptibility and IR spectroscopy analyses. Their reaction with the copper(2) salts in aqueous solutions was studied. It was shown that cation-anion interaction, which was enhanced in the B12 10 6 row, were the case in the amino guanidine closo-borates. The reaction of the amino guanidine closo-borates with the copper(2) salts in aqueous solutions leads to formation either complexes (n = 10, 12) or elemental copper (in the case of B6H62- anion) depending on closo-borate anion BnHn2-

  13. Mass and Energy Balances for Black Liquor Gasification with Borate Autocausticization

    Arosenius, Anna-Karin

    2007-01-15

    Gasification of black liquor is considered to be a promising alternative technique for recovery of black liquor in kraft pulping. Compared to the conventional recovery process, i.e. combustion of black liquor in a recovery boiler, the primary advantage of gasification is the potential to produce biofuels and chemicals. The causticizing demand is though higher for the gasification technology. If the existing lime kiln can not handle the extra load, partial borate autocausticizing may be an alternative. In this work, the energy balance for a kraft pulp mill using black liquor gasification and partial borate autocausticization is compared with a mill using gasification and extended lime causticizing and also with a mill having a conventional recovery cycle. Additionally, the chemical costs for the partial borate autocausticizing is compared to the investment cost of the larger lime kiln. Mass and energy balances are based on the updated reference mill in the MISTRA Research Program, 'The Eco-Cyclic Pulp Mill', producing 2000 ADt of pulp per day. The results show that less energy is released to steam production in a gasifier than in a recovery boiler and instead energy is released in chemical form in the produced syn gas. Using partial borate autocausticizing, the demand of external energy is lowered in the lime kiln compared to extended lime causticization. The borate autocausticization, taking place in the gasifier with black liquor as energy source, only demands a third of the energy saved in the lime kiln. On the other hand the chemical costs for the borate autocausticization exceeds the investment cost for a larger lime kiln after five years.

  14. AFM studies of swift heavy ion and electron irradiated mixed barium strontium borate nonlinear optical crystal

    Single crystals of novel nonlinear optical material of mixed barium strontium borate is grown in our laboratory by employing the low-temperature solution technique. Equal proportion (1:1 molar ratio) of AR grade barium borate and strontium borate are mixed together in double distilled water to prepare a supersaturated solution. The solution is allowed to evaporate at constant temperature (30 deg. C) in a Petri dish for about a week which resulted in the formation of seed crystals. These seed crystals are used to grow larger crystals by suspending them using fine silk thread in the supersaturated mother solution. The solution is allowed to evaporate at constant temperature. This resulted in the growth of good transparent crystals of dimension 15 mmx10 mmx1 mm after about one month. These crystals show good second harmonic generation (SHG) efficiency. The mixed barium strontium borate crystal is found to be a promising nonlinear optical crystal, which possibly can be used for fabrication of photonic devices. The single crystals of mixed barium strontium borate are irradiated by 120 MeV Ag+13 swift heavy ions (SHI) of fluence 5x1011 ions/cm2 at Nuclear Science Centre, New Delhi and also by electrons of 8 MeV energy with a fluence 5.7x109/cm2 using Microtron accelerator at Mangalore University. Surface morphology studies of these crystals are carried out using atomic force microscope. The AFM topographical images of these SHI/electron irradiated single crystals of mixed barium strontium borate are obtained from different frames of the sample taken at different magnifications using atomic force microscope. An attempt is made to explain the surface damage caused due to SHI/electron irradiation using the observed AFM images

  15. Supramolecular assembly of borate with quaternary ammonium: Crystal structure and tunable luminescent properties

    A new borate [C6H16N][B5O6(OH)4] (1) is synthesized hydrothermally by the reaction of isopropyltrimethylammonium hydroxide with boric acid. It crystallizes in the triclinic space group P-1 with the parameters a=9.1578(10) Å, b=9.372(9) Å, c=9.9812(10) Å, α=66.508(2)°, β=74.751(2)°, γ=81.893(2)°. The [B5O6(OH)4]− anions are interlinked via hydrogen bonding forming a 3D supramolecular network containing large cavities, where reside the (CH3)3(i-C3H7) N+ cations. This borate shows tunable luminescent properties with temperature, heating-treatment, exciting-light, and solvents. The fluorescent intensity of 1 enhances 6-fold with decreasing the temperature from 25 K to 78 K. By treatment under different temperatures, the luminescence of 1 shifted from blue to white and the sample treated at 230 °C emits bright white light to naked eyes. The hybrid borate can disperse in different solvents, and shows a red-shifted and intense emission in polar solvents. - Graphical abstract: The new quaternary ammonium borate [C6H17N][B5O6(OH)4] contains a 3D supramolecular network formed by hydrogen bond linked [B5O6(OH)4]− anions and shows tunable luminescent properties with temperature, excitation light, and solvents. Highlights: ► A novel quaternary ammonium borate was synthesized. ► It possesses a supramolecular network fomed by H-bonded [B5O6(OH)4]− anions. ► This borate shows tunable luminescent properties with temperature, heating treatment, excitation light, and solvents

  16. Luminescence properties of the Sm-doped borate glasses

    Kindrat, I.I. [University of Zielona Góra, Institute of Physics, Division of Spectroscopy of Functional Materials, 4a Szafrana Street, 65-516 Zielona Góra (Poland); Padlyak, B.V., E-mail: B.Padlyak@if.uz.zgora.pl [University of Zielona Góra, Institute of Physics, Division of Spectroscopy of Functional Materials, 4a Szafrana Street, 65-516 Zielona Góra (Poland); Vlokh Institute of Physical Optics, 23 Dragomanov Street, 79-005 Lviv (Ukraine); Drzewiecki, A. [University of Zielona Góra, Institute of Physics, Division of Spectroscopy of Functional Materials, 4a Szafrana Street, 65-516 Zielona Góra (Poland)

    2015-10-15

    The optical absorption and photoluminescence (emission and excitation) spectra as well as decay kinetics of a series of the Sm-doped glasses with Li{sub 2}B{sub 4}O{sub 7}, LiKB{sub 4}O{sub 7}, CaB{sub 4}O{sub 7}, and LiCaBO{sub 3} compositions were investigated and analysed. The Li{sub 2}B{sub 4}O{sub 7}:Sm, LiKB{sub 4}O{sub 7}:Sm, CaB{sub 4}O{sub 7}:Sm, and LiCaBO{sub 3}:Sm glasses of high optical quality have been obtained from the corresponding polycrystalline compounds in the air atmosphere, using a standard glass technology. On the basis of electron paramagnetic resonance (EPR) and optical spectra analysis it was shown that the samarium impurity is incorporated into the glass network as Sm{sup 3+} (4f{sup 5}, {sup 6}H{sub 5/2}) ions, exclusively. All observed 4f – 4f transitions of the Sm{sup 3+} centres in the optical absorption and luminescence spectra of the investigated glasses are identified. Most intense emission band of the Sm{sup 3+} ions peaked about 598 nm ({sup 4}G{sub 5/2} → {sup 6}H{sub 7/2} transition) is characterised by a single exponential decay with typical lifetime values, which depend on the basic glass composition as well as concentration and local structure of the Sm{sup 3+} luminescence centres. The quantum efficiency has been evaluated for observed transitions of the Sm{sup 3+} centres using obtained experimental lifetimes and radiative lifetimes calculated by Judd–Ofelt theory. The calculated high quantum efficiencies and measured quantum yields of luminescence show that the investigated borate glasses are perspective luminescence materials. Energy transfer from the Ce{sup 3+} non-controlled impurity and intrinsic luminescence centres to the Sm{sup 3+} centres has been observed. Peculiarities of the Sm{sup 3+} local structure in the network of investigated glasses have been discussed based on the obtained spectroscopic results and structural data. - Highlights: • The Sm-doped Li{sub 2}B{sub 4}O{sub 7}, LiKB{sub 4}O{sub 7}, Ca

  17. Moessbauer spectroscopic study of the thermal neutron irradiated potassium borate glasses

    Moessbauer study was performed for thermal neutron irradiated potassium borate glasses containing 7 mol % of ferric oxide. The alkali contents of the glasses were changed from 10 to 40 mol %. The decrease of isomer shift was observed by the irradiation of the glasses when the alkali content was higher than 20 mol %. The increase of the quadrupole splitting was also observed in the low alkali content region. These results were discussed in connection with the nuclear reaction of 10B(n,α)7Li and the network structure of the borate glasses. (author)

  18. EVALUATION OF BORATED ALUMINUM PRODUCTS FOR CRITICALITY CONTROL IN 235-F

    Duncan, A.; Sindelar, R.

    2003-05-06

    Plutonium-containing materials are destined for storage in the 235-F vault. The projected amount of stored materials will require the presence of neutron absorber materials. The leading design concept is for the neutron absorber materials to be in non-load-bearing borated aluminum plates lining the walls of the vault. A comprehensive evaluation of the borated aluminum plate materials was performed to identify a suitable material, and verify that these materials would remain effective as neutron absorbers under normal service conditions and for design-basis events, including the fire accident scenario, throughout a 20-year service life. Aluminum 1100 with boron additions is the recommended neutron absorber material for plutonium material storage in the 235-F vault based on boron loading capacity and durability in the storage environment. Borated aluminum 1100 is commercially available up to 4.5 wt. % boron. A detailed comparison was made of the physical, mechanical, and corrosion properties of borated aluminum alloy 1100 to standard alloy 1100-O (-O designating the fully annealed condition) to demonstrate near-equivalency in properties and to justify application of alloy 1100-O properties to the borated product as needed for the degradation analysis. The expected degradation of the borated aluminum is extremely low for storage conditions, including the bounding scenario of an aggressive atmospheric condition. A maximum loss of 0.00029 inches/year would be expected under potentially aggressive atmospheric conditions and would result in a fractional loss of only 0.42 wt. % of the boron present in a 7mm plate for a 20-year storage period. The fraction of Boron-10 consumption by spontaneous neutrons is expected to be less than 10{sup -8} for the 20-year storage in 235-F fully loaded with Pu materials. The borated aluminum alloy 1100 will be thermally stable and unaltered up to near-melt temperature (643°C). Mechanical testing data at elevated temperatures show that the

  19. Corrosion resistance of anodized AZ31 Mg alloy in borate solution containing titania sol

    Guo Yan; Wang Guixiang [Key Laboratory of Superlight Material and Surface Technology, College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); Dong Guojun [Key Laboratory of Superlight Material and Surface Technology, College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China)], E-mail: dgj1129@163.com; Gong Fan; Zhang Lili; Zhang Milin [Key Laboratory of Superlight Material and Surface Technology, College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China)

    2008-09-08

    Anodic films were prepared on the AZ31 magnesium alloy in alkaline borate solution with or without addition of titania sol under the constant potential of 50 V (dc) for 10 min at room temperature. The morphology of the anodic films was observed by scanning electron microscope (SEM). The corrosion resistance of the anodic films was evaluated in 3.5% NaCl solution using fast anti-acid test, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The anodic film formed in borate solution with addition of 4% titania sol has superior uniform surface and higher corrosion resistance than in other conditions.

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

    Fatma H. Margha; Amr M. Abdelghany

    2012-01-01

    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 f...

  1. Luminescence properties of manganese doped zinc-borates with different structure

    A study was made on spectral-luminescent characteristics of zinc-borates with different structure, activated by Mn2+ ions, as well as on prospects of their practical use in gas-discharge indication panels (GIP). Spectral characteristics of zinc metaborate Zn4O(BO2)6 and zinc orthoborate Zn3(BO3)2 under VUV-excitation were investigated. The presented spectral-luminescent characteristics of zinc-borates, activated by Mn2 ions, testify to the promising character of their use in GIP

  2. High arsenic and boron concentrations in groundwaters related to mining activity in the Bigadic borate deposits (Western Turkey)

    This study documents the environmental impacts of borate mines in Bigadic district, which are the largest colemanite and ulexite deposits in the world. Borate-bearing formations have affected the concentrations of some contaminants in groundwater. Groundwater quality is directly related to the borate zones in the mines as a result of water-rock interaction processes. Calcium is the dominant cation and waters are Ca-SO4 and HCO3 type in the mine (Tuelue borate mine) from which colemanite is produced. However in the Simav and Acep Borate Mines, ulexite and colemanite minerals are produced and waters from these open pit mines are Na-HCO3-SO4 types. High SO4 concentrations (reaching 519 mg/L) might be explained by the existence of anhydrite, gypsum and celestite minerals in the borate zone. Groundwater from tuff and borate strata showed relatively low pH values (7-8) compared to surface and mine waters (>8). EC values ranged from 270 to 2850 μS/cm. Boron and As were the two important contaminants determined in the groundwaters around the Bigadic borate mines. Arsenic is the major pollutant and it ranged from 33 to 911 μg/L in the groundwater samples. The concentrations of B in the study area ranged from 0.05 to 391 mg/L. The highest B concentrations were detected at the mine areas. The extension of the borate zones in the aquifer systems is the essential factor in the enrichment of B and As, and some major and trace elements in groundwaters are directly related to the leaching of the host rock which are mainly composed of tuffs and limestones. According to drinking water standards, all of the samples exceed the tolerance limit for As. Copper, Mn, Zn and Li values are enriched but do not exceed the drinking water standards. Sulfate, Al and Fe concentrations are above the drinking water standard for the groundwater samples

  3. Device for conditioning toxic or radioactive wastes containing borate ions and its fabrication process

    Wastes, especially spent ion exchange resins, are mixed in a container with Portland cement, aluminous cement and water to form a cement matrix containing stable phases of borated ettringite type and/or calcium monoboroaluminate. Mechanical resistance is obtained by subsequent encapsulation of the whole in a mortar

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

    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)

  5. Chapter 1. Complex processing of borosilicate ores. 1.1. Properties of borate ores

    This article is devoted to properties of borate ores, including borax (mineral), boric acid (H3BO3), ulexite (mineral), kernite (mineral), hydrocarbocyte (mineral) Ca Mg(B3O4(OH)3)2·3H2O, datolite (mineral) Ca[B OH(Si-4)], and danburite.

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

    Pelliccioni, M.; Prokic, M.; Esposito, A.; Nuccetelli, C.; Christensen, P.

    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 of the...

  7. Synthetic Investigations in Rare-Earth Borates, Gallates, Oxides, and Gallium Oxonitrides at Extreme Conditions

    Hering, Stefanie Alexandra

    2010-01-01

    The present phD thesis concerns synthetic investigations under extreme conditions of high-temperature and high-pressure. The high-temperature / high-pressure experiments, performed using a multianvil high-pressure device, led to the first single crystals of various rare-earth gallates, rare-earth borates, rare-earth oxides and gallium oxonitrides.

  8. Vitrification of the borate waste surrogate using fly ash as an additive

    Borate waste is the main waste from nuclear power plants. Glass is an acceptable waste form because of its ability to accept a wide range of components into its network structure. Vitrification of borate waste from nuclear power plants is an attractive approach from the viewpoint of environment and safety. Fly ash is a headache waste generated from the coal combustion power stations. Fly ash contains high contents of SiO2 and Al2O3, which are also the most important glass structure formers. This project takes fly ash as a main additive to vitrify borate waste. Na2O, the only non-waste additive was added, in order to decrease the melting temperature. The experimental results indicate that glasses with ∼ 60 wt% of fly ash, ∼ 30 wt% of borate waste, and ∼ 10 wt% of Na2O have good chemical durability and good processability. This approach not only obtained the minimum cost, but also find a treatment method for the industrial waste

  9. Preparation of α-Bromoketones Involving the Reaction of Enol Triethyl Borates with N-Bromosuccinimide

    Izabella Jastrzebska

    2013-01-01

    The ketones (5α- and 5β-cholestan-3-one and (1S,7aS)-1-tert-butoxy-hexahydro-7a-methyl-1H-inden-5-one) were efficiently α-monobrominated by treatment of the corresponding enol triethyl borates with N-bromosuccinimide (NBS).

  10. Synthesis and study on the luminescence properties of cadmium borate phosphors

    Highlights: • Cadmium borate synthesized by solid state sintering technique. • Neutron sensitivity of the material ten times that of TLD-600. • Gamma sensitivity is found to be twice that of TLD-100. • Gamma response is linear from 0.1 to 103 mGy. - Abstract: Cadmium borate compound prepared through wet chemical reaction from the starting chemicals followed by high temperature solid state synthesis below the melting point to get the final TL phosphor powder. Phase purity and bond details of cadmium borate crystals are characterized using X-ray diffraction technique and infrared spectroscopy. Feasibility of these materials for radiation dosimetry applications was studied after gamma and neutron irradiation. Gamma irradiation of undoped phosphors show a single peak around 185 °C whereas doping with gadolinium and silver, new more intense peak observed at 290 °C. Irradiation to thermal neutrons revealed single peak around 170 °C for all the phosphors. TL emission spectra and photoluminescence (PL) studies were also carried out on the phosphors. These borate materials are found to be highly sensitive to neutrons and hence can be used for neutron detection. Neutron sensitivity of the material is about ten times that of TLD-600

  11. Geochemical characteristics of Kırka (Sarıkaya) borate deposit, northwestern Anatolia, Turkey

    İ Koçak; Ş Koç

    2016-02-01

    The Kırka borate deposit was deposited in a Miocene lacustrine basin which is closely associated with volcanic activity which lasted from Paleogene to the beginning of Quaternary. Borate mineralization alternates with claystone, mudstone, tuff and fine-layered limestone and mostly shows a lenticular structure. The mineral paragenesis is composed of borax, tincalconite, ulexite, kurnakovite, probertite, tunellite, colemanite, dolomite, smectite group minerals, illite and some firstly reported minerals for the Kırka deposit including hydrochloroborite, brianroulstonite, hilgardite-4M and searlesite minerals. In comparison to average values of earth crust, concentrations of Cs, Sr, Li, As and Se were significantly enriched with respective rates of 21, 15, 14, 3 and 188 folds. Regarding KY, KS1 and KS2 locations, there are differences in both element abundances and their geochemical tendencies which are attributed to variations in discharge regime and physico-chemical conditions of the depositional environment. Independent behaviour of B2O3 might indicate that boron is not associated with clays and carbonates and, therefore, most part of boron must be derived from volcanic activity (hydrothermal solutions, gases). REE data indicate that the Kırka borate deposit was formed in a sedimentary environment where highly alkaline (high pH) hydrothermal solutions also took part in borate precipitation process.

  12. Low-energy collisionally activated dissociation of pentose-borate complexes

    Pepi, Federico; Garzoli, Stefania; Tata, Alessandra; Giacomello, Pierluigi

    2010-01-01

    Pentose-borate 1:1 complexes were generated in the ESI source of a triple quadrupole and ion trap mass spectrometer by electrospray ionization of Na2B4O7 and pentose (arabinose, lyxose, ribose, xylose) 2:1 solution in CH3CN/H2O. The study of their low-energy collisionally activated dissociation (CAD) demonstrated that ribose and lyxose are preferentially complexed at the C2-C3 cis-diol function whereas arabinose and xylose are esterified at the C1-C2 hydroxyl groups. No evidence was found of the stronger affinity for ribose to borate. The ribose probiotic rule can be explained by considering its peculiar capability, among the investigated pentoses, to almost totally complex the borate anion at the C2-C3 hydroxyl group, thus enabling the subsequent stages of nucleotide assembly, such as phosphorylation and linkage to the nucleobases. Finally, the differences observed in the pentose-borate complex CAD spectra can be used for the mass spectrometric discrimination of isomeric pentoses in complex mixtures.

  13. Modification of the sanitary ware body by fluxes containing zinc borate

    The influence of fluxes containing zinc borate on the sintering process and on the resulting sanitary ware properties was investigate. It was stated that these fluxes could diminish the firing temperature of the experimental bodies by 100-150 C, and assure a small increase in their bending strength and as well in their thermal shock resistance. (author). 7 refs, 3 figs, 3 tabs

  14. High-Pressure Synthesis and Characterization of New Actinide Borates, AnB4O8 (An=Th, U)

    Hinteregger, Ernst; Hofer, Thomas S.; Heymann, Gunter; Perfler, Lukas; Kraus, Florian; Huppertz, Hubert

    2013-01-01

    New actinide borates ThB4O8 and UB4O8 were synthesized under high-pressure, high-temperature conditions (5.5 GPa/1100 °C for thorium borate, 10.5 GPa/1100 °C for the isotypic uranium borate) in a Walker-type multianvil apparatus from their corresponding actinide oxide and boron oxide. The crystal structure was determined on basis of single-crystal X-ray diffraction data that were collected at room temperature. Both compounds crystallized in the monoclinic space group C2/c (Z=4). Lattice param...

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

    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 B4C/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 H3BO3 and B4C. The B4C optimum pyrohydrolysis conditions were identified. Wax samples were mixed with U3O8, which prevents the sample from flare up, and also accelerates the extraction of boron. Pyrohydrolysis was carried out with moist O2 at 950℃ for 60 and 90 min for wax with H3BO3 and wax with B4C, respectively. Two simple methods of separation based on alkali extraction and melting wax in alkali were also developed exclusively for wax with H3BO3. 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)

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

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

    2016-05-01

    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. PMID:27055170

  17. Bis(pyrazolyl)(thioimidazolyl)borate ligands: the missing member in the N3...S3 scorpionate series.

    Benkmil, Boumahdi; Ji, Mian; Vahrenkamp, Heinrich

    2004-12-27

    The anionic bis(pyrazolyl)(thioimidazolyl)borate ligands BpMt(R) with R = tert-butyl and isopropyl were obtained as their potassium salts by reacting potassium tris(pyrazolyl)borate with the corresponding thioimidazoles in the melt at 150 degrees C. They were applied to form some tetrahedral zinc complexes and identified by the crystal structures of (BpMt(t-Bu))ZnCl and (BpMt(i-Pr))Zn-SC(6)H(4)-p-Cl. PMID:15606159

  18. Synthesis and properties of bis(p-aminosalicyl)borates of the 2 group metals of periodic system

    Potassium, zinc and cadmium bis(n-aminosalicyl) borates of the Me[N2C14H10O6B]2xnH2O composition have been obtained. The densities and crystal lattice plane spacings have been determined and the IR absorption spectra have been recorded. A tentative structure of the bis(n-aminosalicyl) borates is suggested on the basis of analysis of the IR spectra

  19. Borate cross-linked graphene oxide-chitosan as robust and high gas barrier films

    Yan, Ning; Capezzuto, Filomena; Lavorgna, Marino; Buonocore, Giovanna G.; Tescione, Fabiana; Xia, Hesheng; Ambrosio, Luigi

    2016-05-01

    Chitosan (CS) is one of the most promising polymers due to its biocompatibility, biodegradability, and natural abundance. However, its poor mechanical and barrier properties make it difficult to satisfy a wide range of applications. Herein, borate ions, originating from the hydrolysis of sodium tetraborate decahydrate (borax), have been used to crosslink chitosan and graphene oxide (GO) nanocomposites. Chitosan films consisting of 1.0 wt% boron and 1.0 wt% GO exhibit a significant improvement in both the toughness and oxygen barrier properties compared to pristine chitosan. In particular the tensile strength of the samples after thermal treatment increases by ~160% compared to pristine chitosan, whereas their oxygen permeability reduces by ~90%. This is ascribed to the chemical crosslinking between chitosan and GO nanoplatelets through borate ions, as well as the formation of a layered morphology with graphene nanoplatelets oriented parallel to the sample surface. The exceptional robust and high gas barrier film has promising application in the packaging industry. The borate-crosslinking chemistry represents the potential strategy for improving properties of other polymer nanocomposites.Chitosan (CS) is one of the most promising polymers due to its biocompatibility, biodegradability, and natural abundance. However, its poor mechanical and barrier properties make it difficult to satisfy a wide range of applications. Herein, borate ions, originating from the hydrolysis of sodium tetraborate decahydrate (borax), have been used to crosslink chitosan and graphene oxide (GO) nanocomposites. Chitosan films consisting of 1.0 wt% boron and 1.0 wt% GO exhibit a significant improvement in both the toughness and oxygen barrier properties compared to pristine chitosan. In particular the tensile strength of the samples after thermal treatment increases by ~160% compared to pristine chitosan, whereas their oxygen permeability reduces by ~90%. This is ascribed to the chemical

  20. TRPM7 channel regulates PDGF-BB-induced proliferation of hepatic stellate cells via PI3K and ERK pathways

    Fang, Ling, E-mail: fangling_1984@126.com; Zhan, Shuxiang; Huang, Cheng; Cheng, Xi; Lv, Xiongwen; Si, Hongfang; Li, Jun, E-mail: lj@ahmu.edu.cn

    2013-11-01

    TRPM7, a non-selective cation channel of the TRP channel superfamily, is implicated in diverse physiological and pathological processes including cell proliferation. Recently, TRPM7 has been reported in hepatic stellate cells (HSCs). Here, we investigated the contribution role of TRPM7 in activated HSC-T6 cell (a rat hepatic stellate cell line) proliferation. TRPM7 mRNA and protein were measured by RT-PCR and Western blot in rat model of liver fibrosis in vivo and PDGF-BB-activated HSC-T6 cells in vitro. Both mRNA and protein of TRPM7 were dramatically increased in CCl{sub 4}-treated rat livers. Stimulation of HSC-T6 cells with PDGF-BB resulted in a time-dependent increase of TRPM7 mRNA and protein. However, PDGF-BB-induced HSC-T6 cell proliferation was inhibited by non-specific TRPM7 blocker 2-aminoethoxydiphenyl borate (2-APB) or synthetic siRNA targeting TRPM7, and this was accompanied by downregulation of cell cycle proteins, cyclin D1, PCNA and CDK4. Blockade of TRPM7 channels also attenuated PDGF-BB induced expression of myofibroblast markers as measured by the induction of α-SMA and Col1α1. Furthermore, the phosphorylation of ERK and AKT, associated with cell proliferation, decreased in TRPM7 deficient HSC-T6 cells. These observations suggested that TRPM7 channels contribute to perpetuated fibroblast activation and proliferation of PDGF-BB induced HSC-T6 cells via the activation of ERK and PI3K pathways. Therefore, TRPM7 may constitute a useful target for the treatment of liver fibrosis. - Highlights: • Upregulation of TRPM7 mRNA and protein in the fibrotic livers from CCl{sub 4}-treated rats. • Increasing expression of TRPM7 mRNA and protein during HSC activation. • Blockade of TRPM7 inhibited the PDGF-BB induced proliferation of HSC-T6 cells. • Blockade of TRPM7 decreased α-SMA and Col1α1 expressions in activated HSC-T6 cells. • TRPM7 up-regulation contributes to the activation of ERK and AKT pathways.

  1. Two chromogranin a-derived peptides induce calcium entry in human neutrophils by calmodulin-regulated calcium independent phospholipase A2.

    Dan Zhang

    Full Text Available BACKGROUND: Antimicrobial peptides derived from the natural processing of chromogranin A (CgA are co-secreted with catecholamines upon stimulation of chromaffin cells. Since PMNs play a central role in innate immunity, we examine responses by PMNs following stimulation by two antimicrobial CgA-derived peptides. METHODOLOGY/PRINCIPAL FINDINGS: PMNs were treated with different concentrations of CgA-derived peptides in presence of several drugs. Calcium mobilization was observed by using flow cytometry and calcium imaging experiments. Immunocytochemistry and confocal microscopy have shown the intracellular localization of the peptides. The calmodulin-binding and iPLA2 activating properties of the peptides were shown by Surface Plasmon Resonance and iPLA2 activity assays. Finally, a proteomic analysis of the material released after PMNs treatment with CgA-derived peptides was performed by using HPLC and Nano-LC MS-MS. By using flow cytometry we first observed that after 15 s, in presence of extracellular calcium, Chromofungin (CHR or Catestatin (CAT induce a concentration-dependent transient increase of intracellular calcium. In contrast, in absence of extra cellular calcium the peptides are unable to induce calcium depletion from the stores after 10 minutes exposure. Treatment with 2-APB (2-aminoethoxydiphenyl borate, a store operated channels (SOCs blocker, inhibits completely the calcium entry, as shown by calcium imaging. We also showed that they activate iPLA2 as the two CaM-binding factors (W7 and CMZ and that the two sequences can be aligned with the two CaM-binding domains reported for iPLA2. We finally analyzed by HPLC and Nano-LC MS-MS the material released by PMNs following stimulation by CHR and CAT. We characterized several factors important for inflammation and innate immunity. CONCLUSIONS/SIGNIFICANCE: For the first time, we demonstrate that CHR and CAT, penetrate into PMNs, inducing extracellular calcium entry by a CaM-regulated i

  2. Blends of lithium bis(oxalato)borate and lithium tetrafluoroborate: Useful substitutes for lithium difluoro(oxalato)borate in electrolytes for lithium metal based secondary batteries?

    Highlights: • Stability studies at salts with the difluoro(oxalato)borate anion show that ligand exchange occurs under thermal stress at 60 °C. • NMR measurements at solutions of LiBOB/LiBF4 blend electrolytes show that ligand exchange occurs in solutions at room temperature as well. • Formation of traces of LiDFOB in LiBOB/LiBF4 blend electrolytes is responsible for the favorable SEI and excellent lithium cycling. • SEI compositions of blend electrolytes became more similar to the SEI composition of the LiDFOB-based electrolyte with increasing LiBF4 content. • LiBOB/LiBF4 blend electrolytes show a superior lithium cycling performance compared to single salts nearly reaching the performance of LiDFOB based electrolytes. -- Abstract: This work was inspired by the observation that some borates exchange their ligands that are attached to boron. Therefore, we investigated the effect of blends of two salts, lithium bis(oxalato)borate (LiBOB), lithium tetrafluoroborate (LiBF4) on lithium cycling on copper with solutions based on ethylene carbonate (EC) and diethyl carbonate (DEC) (3:7, by wt.). Coulombic efficiencies of dissolution rate (D-rate) tests demonstrated an enhanced performance of LiBOB/LiBF4 blend electrolytes compared to the LiBOB-based and LiBF4-based electrolytes, increasing with increasing LiBF4 content. The coulombic efficiencies of the LiBOB/LiBF4 blend electrolyte with highest LiBF4 content reached almost the coulombic efficiencies of the lithium difluoro(oxalato)borate (LiDFOB) based electrolyte at high current densities in D-rate tests. Voltage drop values, conductivity measurements, and AC impedance measurements show the good performance of the LiBOB/LiBF4 blend electrolytes. The composition of the solid electrolyte interphase (SEI) of the LiBOB/LiBF4 blend electrolytes studied by X-ray photoelectron spectroscopy (XPS) becomes more similar to the composition of the SEI of the LiDFOB-based electrolyte with increasing LiBF4 content. Nuclear

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

    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.

  4. Computational investigation of the neutron shielding and activation characteristics of borated concrete with polyethylene aggregate

    This paper presents the result of a computational study to investigate the neutron shielding and activation characteristics of concretes containing boron carbide and polyethylene. Various mixes were considered with changes in the contents of boron carbide and polyethylene aggregate. The Monte Carlo simulation code MCNP-5 was utilized to determine the transmission of neutron through concrete at different energies from 0.1 eV to 1 MeV, and ORIGEN-S code was then used to predict activation characteristics of the concretes. It was shown that the replacement of polyethylene in borated concrete greatly enhanced the shielding efficiency of the concrete, and total activity levels of the concrete were considerably decreased with this replacement. Furthermore, double-layered structures having the first layer of polyethylene aggregate-replaced concrete and the second layer of 2 wt% borated concrete are shown to improve shielding efficiency more significantly than monolithic structures

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

    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.

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

    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.

  7. Optical absorption and fluorescence properties of Er3+ in sodium borate glass

    Y C Ratnakaram; J Lakshmi; R P S Chakradhar

    2005-08-01

    Spectroscopic properties of Er3+ ions in sodium borate glass have been studied. The indirect and direct optical band gaps (opt) and energy level parameters (Racah (1, 2 and 3), spin-orbit (4f) and configurational interaction ()) are evaluated. Spectral intensities for various absorption bands of Er3+ doped sodium borate glass are calculated. Using Judd–Ofelt intensity parameters (2, 4, 6), radiative transition probabilities (), branching ratios () and integrated absorption cross sections ( ) are reported for certain transitions. The radiative lifetimes (R) for different excited states are estimated. From the fluorescence spectra, the emission cross section (p) for the transition, ${}^{4}I_{13/2} \\rightarrow {}^{4}I_{15/2}$ is reported.

  8. Neutron Irradiation Effects on Optical Properties of Sm-Doped Lead Borate Glasses

    Sm+3 doped lead borate glass (B2O3 -PbO-Al2O3) samples were prepared with different concentrations of Sm+3 using the normal melt quench technique. The prepared glass samples were irradiated using (5 Ci) 241AmBe neutron source with neutron flux of 4.1 E 7 n/cm2.sec. A study of the effect of both Sm2O3 content and neutron irradiation doses on some optical properties of Sm2O3doped lead borate glasses ( B2O3-PbO- Al2O3) have been performed. Optical parameters such as: the absorption coefficient (α), Urbach’s energy (Eu). Fermi energy (Ef), direct and indirect optical energy gap (Eogd and Eogind) has been evaluated.

  9. Verification of effectiveness of borated water shield for a cyclotron type self-shielded

    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 18F-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)

  10. Study on ultrasonic velocity and elastic properties of γ-radiated borate classes

    Longitudinal and shear ultrasonic velocities were measured in different compositions of sodium borate glass samples before and after irradiation with γ-rays. Measurements were carried out at room temperature and at 4 MHz frequency using pulse echo technique. Densities of the glass samples were measured using displacement method while toluene was used as immersion liquid. Elastic constants were calculated as well as Debye temperature, softening temperatures and microhardness for all glass samples. Results showed that the effect of radiating sodium borate glass with γ-radiation had no noticeable change on ultrasonic velocity. However, the effect of increasing sodium oxide content on ultrasonic velocity was very clear. The increase in velocity was attributed to the gradual increase in the rigidity of the glass and hence strengthening of the network due to the gradual change of boron atoms from the three-fold to the four-fold coordination of oxygen atoms. (author)

  11. Structural systematic and crystal chemistry of novel borates with REE, Pb, Sr, and alkali metals

    Crystal structures of novel borates with REE, Pb, Sr and alkali metals were analyzed using classical fundamental buildings blocks approach. It is demonstrated that hexa-, penta-, tetra-, tri- and diborates subdivisions in systematic are real families of structures with the common peculiarities. According to the symmetrical way and the degree of FBB condensation structural-generic rows exist in every of subdivisions. Mega- or polyborates subdivision is valid for the structures with the different types of simplest FBB. In all new complex borates it is possible to separate FBB of equal or different types which are presented in isolated form or are connected into chains, layers or frameworks, and to find unexpected correlation between structures. The possibility to recognize and to visualize in this approach the polarity or non-polarity of the structural units and correspondingly the polarity or nonpolarity of the structures in the whole is very important for the conclusion on structure-properties relation. (orig.)

  12. Moessbauer spectroscopic study of the formation of non-bridging oxygen in the potassium borate glasses

    Moessbauer spectroscopic study was performed to investigate the formation of non-bridging oxygen in the potassium borate glasses denoted by the formula of x K2O(100 - x) B2O3 x 7 Fe2O3 (0 3+ decreased continuously with the concentration of the alkali oxide in the glass, showing the increase of the symmetry around the Fe3+ ions. The isomer shift value also decreased in almost the same x region. The drastic decrease of Moessbauer parameters was attributed to the formation of non-bridging oxygen at the adjacent site of the Fe3+ ions. In the region of lower alkali content (less than 10 mol%), Moessbauer spectra only showed the absorption due to α-Fe2O3. X-ray powder diffraction patterns also displayed the existence of α-Fe2O3, together with the microcrystal of potassium borate. (orig.)

  13. Computational investigation of the neutron shielding and activation characteristics of borated concrete with polyethylene aggregate

    Park, S.J.; Jang, J.G.; Lee, H.K., E-mail: leeh@kaist.ac.kr

    2014-09-15

    This paper presents the result of a computational study to investigate the neutron shielding and activation characteristics of concretes containing boron carbide and polyethylene. Various mixes were considered with changes in the contents of boron carbide and polyethylene aggregate. The Monte Carlo simulation code MCNP-5 was utilized to determine the transmission of neutron through concrete at different energies from 0.1 eV to 1 MeV, and ORIGEN-S code was then used to predict activation characteristics of the concretes. It was shown that the replacement of polyethylene in borated concrete greatly enhanced the shielding efficiency of the concrete, and total activity levels of the concrete were considerably decreased with this replacement. Furthermore, double-layered structures having the first layer of polyethylene aggregate-replaced concrete and the second layer of 2 wt% borated concrete are shown to improve shielding efficiency more significantly than monolithic structures.

  14. Molecular design of nanometric zinc borate-containing polyimide as a route to flame retardant materials

    Zinc borate (Zn2B6O11.3H2O) nanoparticles were successfully prepared by using an emulsion liquid membrane (W/O/W emulsion) to control the size of particles with Na2B4O7.10H2O, boric acid and ZnSO4.7H2O as raw materials. All materials were dispersed with the polyimide (PI) precursor, poly (amic acid). Using a combination of dissolving the poly (amic acid) and mixing fatty acid surfactant-coated zinc borate nanoparticles; we have demonstrated the formation of nanocomposites with uniform nanoparticles dispersion. We report the first deposition of nanocomposite polyimides from solution using spin-coating. The microstructures and morphology of the as-obtained samples were studied by X-ray diffraction (XRD), infrared spectra (IR), scanning electron microscopy (SEM) equipped with an energy-dispersive X-ray spectrometer (EDX), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA)

  15. Physical and optical characterization of Er3+ doped lead-zinc-borate glass.

    Sooraj Hussain, N; Cardoso, P J; Hungerford, G; Gomes, M J M; Ali, Nasar; Santos, J D; Buddhudu, S

    2009-06-01

    This paper reports on the systematic optical characterization of Er3+ (1.0%) doped lead-zinc-borate glass from the measured absorption, luminescence and fluorescence lifetime decay curve profiles. By the application of the Judd-Ofelt theory, spectral intensities of the absorption bands have been analysed and these absorption results have been used in evaluating the luminescence properties of the Er3+ doped lead-zinc-borate glass. Stimulated emission cross-sections (sigmapE) of the measured emission transitions have been computed. Based on the measured glass density, and refractive indices, other related physical parameters have also been evaluated. Further, the structural and morphology of the glass material have also been investigated from X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy analysis. PMID:19504881

  16. Fluorescence properties of Eu3+ ions doped borate and fluoroborate glasses containing lithium, zinc and lead.

    Venkatramu, V; Babu, P; Jayasankar, C K

    2006-02-01

    The influence of glass composition on the fluorescence properties of Eu3+ ions doped borate and fluoroborate glasses modified with Li+, Zn2+ and Pb2+ cations have been investigated. The magnitude of splittings of 7F1 levels are analyzed using crystal-field (CF) analysis. The relative intensities of 5D0 --> 7F2 to 5D0 --> 7F1 transitions, crystal-field strength parameters and decay times of the 5D0 level have been determined and are found to be lower for Pb based glasses than those of Zn/Li based glasses. The lifetimes of 5D0 level are found to increase when borate glasses are modified with pure fluorides than with oxides and oxyfluorides. The fluorescence decay of 5D0 level fits perfect single exponential in the Eu3+:glass systems studied which indicates the absence of energy transfer between Eu3+ ions in these glasses. PMID:15979397

  17. Structural, optical and glass transition studies on Nd3+-doped lead bismuth borate glasses

    Nd3+-doped lead bismuth borate (PbO-Bi2O3-B2O3) glasses were prepared with different concentrations of Nd3+. The structural studies were done through FTIR spectral analysis. The glass transition studies were done through differential scanning calorimetry. The optical analysis was done by using Judd-Ofelt theory. The structural study reveals that the glass has [BiO3], BO4, BO3 and PbO4 units as the local structures

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

    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.

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

    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 m3 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)

  20. Surface plasmons for fluorescence enhancement in Sm-doped borate glasses

    Heat treatment of Sm-activated lithium and sodium borate glasses which are additionally doped with silver oxide leads to a reduction of the doped silver ions and to the formation of metallic silver nanoparticles indicated by a broad plasmon-related absorption band in the visible spectral range. The influence of the plasmon resonance field enhancement on the Sm3+ fluorescence excitation bands is too small to lead to enhanced fluorescence emission intensities.

  1. Process and plant for the treatment of radioactive residues from borate containing sewage

    Radioactive residues from borate-containing waste water can be concentrated in an evapouration plant. The concentrate is further processed by the addition of sodium hydroxide giving molar proportions of sodium to boron of approx. 0.7 or 0.3. The concentrates are then boiled down in a heatable container to at least twice the original solid matter content and then filled into transport containers which are then removed for safe intermediate storage. (orig.)

  2. Reproductive effects of sodium borates on male employees: birth rate assessment.

    Whorton, M D; Haas, J L; Trent, L; Wong, O

    1994-01-01

    OBJECTIVES--The purpose of the study was to investigate potential reproductive effects of sodium borates on occupationally exposed male employees at a large mining and production facility in the Mojave Desert of California. METHODS--The standardised birth ratio (SBR) was used to assess fertility of the male employees. Live births were the measured end point, and the rate of female to male offspring was also assessed. Data were collected through a questionnaire after a series of on site introd...

  3. (11)B MAS NMR and First-Principles Study of the [OBO3] Pyramids in Borates.

    Zhou, Bing; Sun, Wei; Zhao, Biao-Chun; Mi, Jin-Xiao; Laskowski, Robert; Terskikh, Victor; Zhang, Xi; Yang, Lingyun; Botis, Sanda M; Sherriff, Barbara L; Pan, Yuanming

    2016-03-01

    Borates are built from the [Bϕ3] planar triangles and the [Bϕ4] tetrahedral groups, where ϕ denotes O or OH. However, the [Bϕ4] groups in some borates are highly distorted to include three normal B-O bonds and one anomalously long B-O bond and, therefore, are best described as the [OBO3] pyramids. Four synthetic borates of the boracite-type structures (Mg3B7O13Br, Cu3B7O13Br, Zn3B7O13Cl, and Mg3B7O13Cl) containing a range of [OBO3] pyramids were investigated by multifield (7.05, 14.1, and 21.1 T) (11)B magic-angle spinning nuclear magnetic resonance (MAS NMR), triple quantum (3Q) MAS NMR experiments, as well as density functional theory calculations. The high-resolution (11)B MAS NMR spectra supported by theoretical predictions show that the [OBO3] pyramids are characterized by isotropic chemical shifts δiso((11)B) from 1.4(1) to 4.9(1) ppm and nuclear quadrupole parameters CQ((11)B) up to 1.3(1) MHz, both significantly different from those of the [BO4] and [BO3] groups in borates. These δiso((11)B) and CQ((11)B) values indicate that the [OBO3] pyramids represent an intermediate state between the [BO4] tetrahedra and [BO3] triangles and demonstrate that the (11)B NMR parameters of four-coordinate boron oxyanions are sensitive to local structural environments. The orientation of the calculated unique electronic field gradient tensor element Vzz of the [OBO3] pyramids is aligned approximately along the direction of the anomalously long B-O bond, corresponding to B-2pz with the lowest electron density. PMID:26914372

  4. Reproductive effects of inorganic borates on male employees: birth rate assessment.

    Whorton, D; Haas, J.; Trent, L

    1994-01-01

    The purpose of this study was to investigate the potential for reproductive effects of inorganic borate compounds on male employees. The standardized birth ratio (SBR) methodology was used to assess fertility among male employees, using live births as the measured end point. The ratio of female to male births was also assessed. Data were collected via questionnaires and telephone follow-up interviews. Medical insurance records were assessed for nonresponders. Exposures were assessed using thr...

  5. Dose related acute irritant symptom responses to occupational exposure to sodium borate dusts.

    X. Hu; Wegman, D H; Eisen, E A; Woskie, S R; Smith, R G

    1992-01-01

    A repeated measurement design was employed in the study of acute symptoms of eye and respiratory tract irritation resulting from occupational exposure to sodium borate dusts. The symptom assessment of the 79 exposed and 27 unexposed subjects comprised interviews before the shift began and then at regular hourly intervals for the next six hours of the shift, four days in a row. Exposures were monitored concurrently with a personal real time aerosol monitor. Two different exposure profiles, a d...

  6. Spectroscopic analysis of Ho3+ transitions in different modifier oxide based lithium–fluoro-borate glasses

    In recent investigations it was observed that the presence of different structural groups in borate glasses was favorable for spectroscopic investigations of rare earth doped borate glasses. Consequent to these observations, the heavy metal fluoride glasses doped with Ho3+ ions received much attention due to their wide transparency in the ultraviolet to infrared region. Keeping these observations in view, the present paper makes an attempt to present spectral investigations of Ho3+ doped lithium–fluoro-borate glasses of the compositions Li2B4O7–BaF2–NaF–MO (where M=Mg, Ca, Cd and Pb), Li2B4O7–BaF2–NaF–MgO–CaO and Li2B4O7–BaF2–NaF–CdO–PbO. These rare earth doped glasses were synthesized by melt quenching technique and an investigation was carried out to observe the structural (SEM and FT-IR) and optical (absorption and luminescence) properties. The paper also aims at the determination of three phenomenological Judd–Ofelt intensity parameters and special attention was paid to study the emission properties by employing the J–O intensity parameters. The visible emission spectra of Ho3+ ion in different lithium–fluoro-borate glasses were recorded by exciting the samples at 409 nm. The results revealed that among all the glass matrices, cadmium glass matrix have shown higher stimulated emission cross-section, which indicates that this is a good lasing material at this wavelength and highly useful for laser excitation

  7. Thermal Properties of Borate Crystals for High Power Optical Parametric Chirped-Pulse Amplification

    Riedel, Robert; Rothhardt, J.; Tünnermann, A.; Prandolini, Mark; Tavella, F.; Beil, K.; Gronloh, B.; Klenke, A.; Höppner, H.; M. Schulz; Teubner, U.; Kraenkel, Christian; Limpert, J.

    2014-01-01

    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 line...

  8. Establishment of PCP composition diagrams for cementations of borate wastes using response surface methodology

    For the purpose of quality assurance, it is requested by the regulatory authority in the solidification of low-level radioactive waste (LLRW) to implement the 'process control program (PCP)', in which the condition of solidification should be decided in advance of solidification according to the so-called 'PCP composition diagrams', to assure that the condition of solidification is within established process parameters and that the quality of solidified LLRW meets quality criteria. In this paper, PCP composition diagrams for the cementation of radioactive liquid borate wastes were established with response surface methodology, including using the simplex centroid design to allocate experimental conditions and statistical curve-fitting techniques to construct quality models. The constructed models were verified to have a confidence level higher than 95% by doing the lack-of-fit test on them. Quality contours of solidified borate wastes were thus established based on mathematical and statistical principles and have been used as composition diagrams in the process control program of radioactive borate wastes solidification at Ma-An-Shan nuclear power station of Taiwan Power Company. The solidification agent used in this study was a mixture of Portland type-II cement and lime powder with a weight ratio of 1/0.22. Quality contours for solidified borate wastes including free-standing water content, compressive strength, water resistance, thawing and freezing resistance, irradiation resistance, and leaching resistance were established. Characteristics of these quality contours were also discussed. With these contours, the performance of the final waste form can be assured and consequently a volume reduction will also be achieved, when the PCP is implemented. (author)

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

    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

  10. High electric field and switching phenomena in some borate and vanadate glasses

    The study of conduction mechanism, high-field characteristics and switching phenomena of borate and vanadate glasses have been extended to high electric fields of the order of 5.7·104 V cm-1 or higher (beyond the ohmic region), when memory switching phenomena are observed in thin blown films of ZnO-B2O3 and in thicker BaO-V2O5 glasses. Typical voltage-current characteristics are given and explained

  11. Growth Kinetics and Electronic Properties of Passive Film of Zinc in Borate Buffer Solution

    We have investigated the growth kinetics and electronic properties of passive film of zinc in borate buffer solution. The oxide film formed in passivation process of zinc has showed the electronic properties of n-type semiconductor based on the Mott-Schottky equation. And it was found out that the oxide film consisted ZnO and Zn(OH)2 was composed of deep and shallow donors

  12. Optical characterization of TCO films on borate glasses for high efficiency solar cells

    Steudel, Franziska; Miclea, Paul-Tiberiu; Teuscher, Nico; Heilmann, Andreas; Schweizer, Stefan

    2012-06-01

    Two different transparent conductive oxides (TCO) were deposited by magnetron sputtering on borate glasses. The influence of sputtering conditions on optical, electrical and microstructural properties was much higher for indium tin oxide (ITO) than for aluminium-doped zinc oxide (AZO) films. Specific resistivity values obtained from simulation of the optical spectra are in good agreement with values obtained from four-point probe measurements.

  13. Comparison of Lithium Gadolinium Borate Crystal Shards in Scintillating and Nonscintillating Plastic Matrices

    Kazkaz, Kareem; Bowden, Nathaniel S.; Pedretti, Marisa

    2011-01-01

    We present a method for detecting neutrons using scintillating lithium gadolinium borate crystal shards in a plastic matrix while maintaining high gamma rejection. We have procured two cylindrical detectors, 5"\\times5", containing 1% crystal by mass. Crystal shards have a typical dimension of 1 mm. One detector was made with scintillating plastic, and one with nonscintillating plastic. Pulse shape analysis was used to reject gamma ray backgrounds. The scintillating detector was measured to ha...

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

    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) B2O3 − 20 CaO – 10 MgO-(y) Dy2O3 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 Dy2O3 concentration of 0.5 mol % were determined for thermoluminescence dosimeter (TLD) reader used

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

    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.

  16. Luminescent properties of Eu{sup 3+}-activated lithium rare earth borates and oxyborates

    Jubera, V.; Chaminade, J.P.; Garcia, A.; Guillen, F.; Fouassier, C

    2003-01-15

    The luminescence characteristics of Eu{sup 3+} in the borates Li{sub 6}Y(BO{sub 3}){sub 3} and Li{sub 3}La{sub 2}(BO{sub 3}){sub 3} and the recently discovered oxyborates LiLa{sub 2}O{sub 2}BO{sub 3}, LiLn{sub 6}O{sub 5}(BO{sub 3}){sub 3} (Ln=Y,Gd) and Li{sub 2}Lu{sub 5}O{sub 4}(BO{sub 3}){sub 3} have been investigated and compared to those in the borates LnBO{sub 3} (Ln=La,Y) and the oxyborates ''Ln{sub 3}BO{sub 6}'' (Ln=La,Gd). The probability of electric dipole f-f transitions is generally markedly higher in oxyborates than in borates. This is ascribed to the highly anisotropic environment of rare earth ions and the low position of the charge transfer states. Consequently, the Eu{sup 3+}-activated oxyborates are characterized by a deeper red emission and faster decay.

  17. Borate-treated strand board from southern wood species: Resistance against decay and mold fungi

    Xinwu Xu

    2013-02-01

    Full Text Available Combined decay and mold resistance of zinc borate-(ZB and calcium borate-(CB treated oriented strand board (OSB from southern mixed hardwood (MHW and southern yellow pine (SYP was investigated. Tests were done with a brown-rot fungus, Gloeophyllum trabeum, and a white-rot fungus, Trametes versicolor, for 8 and 12 weeks, respectively. Wood species and fungus type had significant influence on the decay resistance. Decay caused by the brown-rot fungus was evident for all untreated SYP and mixed MHW controls. White-rot fungus did not cause significant sample weight loss for either species group. In the SYP OSB control inoculated with G. trabeum, the hyphae were abundant in wood rays and cell walls where they primarily penetrated through bordered and simple pits. The incorporation of ZB and CB into OSB provided significant protection against the fungi with no significant weight loss observed in the treated OSB. Microscopic analysis showed distinct evidence of fungal colonization and a thinning pattern of cell wall material. Untreated OSB samples from MHW and commercial OSBs were most susceptible to mold growth after 6 weeks. The borate-modified OSB from MHW and SYP effectively prevented the mold growth.

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

    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.

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

    Omar, R. S.; Wagiran, H.; Saeed, M. A.

    2016-01-01

    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) B2O3 - 20 CaO - 10 MgO-(y) Dy2O3 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 Dy2O3 concentration of 0.5 mol % were determined for thermoluminescence dosimeter (TLD) reader used.

  20. Characteristics of a column suitable for capacity gradient chromatography with a borate eluent.

    Yamamoto, A; Kodama, S; Matsunaga, A; Inoue, Y; Aoyama, T; Kumagai, Y

    2001-04-01

    In capacity gradient elution, the gradient separation of ionic species is achieved by decreasing the ion-exchange capacity of a column during the course of the separation. Diol-type hydroxy groups on the resin surface form anionic complexes with borate as an eluting reagent. Thus, a chemically bonded anion-exchange column enriched with residual hydroxy groups allows the creation of a capacity gradient. An increase in the amount of the complex formed gradually brings about a decrease in the ion-exchange capacity of the column, and strongly bound analyte ions are eluted. We investigated the characteristics of a column suitable for this eluent system. The concentration of borate eluent required to remove the ion-exchange capacity depended inversely on the ratio of the residual hydroxy groups to functional groups. On a column in which this ratio was approximately 100, the ion-exchange capacity could easily be adjusted by using a low concentration of mannitol as a competing reagent. Use of this column led to very small baseline shifts during the borate-mannitol gradients, and to the simultaneous determination of anions with widely varying retention times. PMID:11340979

  1. Improvement of cesium leaching resistance of solidified borate wastes with copper-ferrocyanide-vermiculite adsorbent

    Removal of cesium from deionized water, sea water, and lime water with copper ferrocyanide (CFC) and porous media including silica gel, bentonite, vermiculite, and zeolite were investigated; CFC and vermiculite were incorporated to prepare a compound adsorbent which was used to improve the Cs-leaching resistance of solidified borate wastes. It was shown that the Cs-removal efficiency by CFC is largely affected by pHs of the solutions, good cesium removal occurs in pHs ranged from 3 to 12 and the best from 7 to 10; the effect of Cs concentration is significantly only from lime water for Cs > 10-6 M at high pH and is insignificant from other solutions. Vermiculite and zeolite were shown to have better removal efficiency than silica gel and bentonite, and vermiculite was chosen to incorporate with CFC to make compound adsorbents because of its good compatibility with CFC. Compound adsorbents with different CFC contents were used as additives in the solidification of borate radwaste for improving the cesium leaching resistance of waste forms. Experimental results showed that the measured, cesium leaching index following ANSI/ANS 16.1, was increased from 7.96 to 9.76 by adding 0.25% of a compound adsorbent containing 20% CFC and 80% vermiculite, which indicated that the CFC-vermiculite compound adsorbent is very useful for improving cesium leaching resistance of the solidified borate radwastes

  2. Low temperature phase barium borate: A new optical limiter in continuous wave and nano pulsed regime

    Babeela, C.; Girisun, T. C. Sabari

    2015-11-01

    Low temperature phase barium borate was synthesized by hydrothermal method. XRD analysis confirms the formation of γ-BBO or hydrated barium polyborate (Ba3B6O9(OH)6) which crystallizes in monoclinic system in the P2/c space group. The molecular structure analysis shows the presence of dominant BO4 unit and the hydrated nature of material. γ-BBO exhibits sharp absorption edge at 202 nm and highly transparency in the UV-Visible-NIR region. The peak at 347 nm in the emission spectrum is due to the presence of self-trapped exciton. The third order nonlinear optical properties and limiting behavior of low temperature barium borate in both pulsed and continuous wave regime were studied. The effective 2PA absorption coefficient of γ-BBO under ns pulse excitation is estimated to be 0.38 × 10-10 m/W. The nonlinear absorption coefficient, refractive index and optical susceptibility of the material in cw regime were found to be in the order of 10-5 m W-1, 10-12 m2 W-1, 10-6 esu respectively. In both regimes, low temperature phase barium borate exhibits better optical limiting properties than high temperature phase β-BBO.

  3. Preparation and photoluminescence of some narrow band UVB emitting Pr-Gd doped lanthanum borate phosphors

    The powder samples of the narrow UVB emitting borate phosphors LaBO3- Pr3+Gd3+, LaB5O9- Pr3+Gd3+, LaBaB9O16- Pr3+Gd3+ has been prepared by a novel solution Combustion method. The formation of the samples was confirmed by powder XRD technique. The photoluminescence properties of borate phosphors have been investigated. The borate phosphors LaBO3- Pr3+Gd3+, LaB5O9- Pr3+Gd3+, LaBaB9O16- Pr3+Gd3+ shows strong absorption over a wide UV range from 200-400 nm. Upon excited by 254 nm CV radiations, all these phosphors LaBO3- Pr3+Gd3+, LaB5O9-Pr3+Gd3+, LaBaB9O16- Pr3+Gd3+ shows intense narrowband UVB emission around 311 nm. The optimum concentrations of Pr3+ and Gd3+ are 2% and 10% respectively. In these phosphors no host excitation was observed which indicates the efficient energy transfer from Pr3+ to Gd3+. (author)

  4. Borate glasses doped with Nd3+ ions as laser gain media. Chapter IT-04

    The spectroscopic properties of Nd3+-doped borate based glasses have been discussed. The experimental oscillator strengths (fexp), Judd-Ofelt parameters (Ω2, Ω4 and Ω6), radiative transition probabilities (AR), stimulated emission cross-sections (σem) and radiative lifetimes (τR) have been evaluated and compared with reported Nd3+ -doped borate glasses. Attention has also been focused on hypersensitive radiative transition, 4F3/2 →4I11/2. The variation of peak positions of hypersensitive transition in several glass media is attributed to differences in the crystal-field asymmetry. The general trend Ω2 > Ω4,6 indicate the higher covalency of the ion-ligand bond and lower symmetry of the Nd3+ ion site. This result also explains the higher intensity of hypersensitive transition and the nephelauxetic effect possessed by these glasses. The higher oscillator strength for hypersensitive transition is noted when the borate content is 49.5 mol%. (author)

  5. Enhancing mechanical properties of ceramic papers loaded with zeolites using borate compounds as binders

    Juan P. Cecchini

    2013-02-01

    Full Text Available NaY zeolite-containing ceramic papers were prepared by a papermaking technique with a dual polyelectrolyte retention system that implied the use of cationic and anionic polymers. To improve their mechanical properties, we found that some borate compounds could be successfully used as ceramic binders. Three types of sodium and/or calcium borates were tested as binders: colemanite, nobleite, and anhydrous ulexite. The improvement in the mechanical properties depends both on the borate used and on the calcination temperature. By XRD it was determined that the faujasite structure collapsed after calcination at 700°C, which limited the final calcination temperature of zeolitic ceramic papers. Different amounts of NaY zeolite were added to ceramic papers and, as observed by SEM, faujasite particles were well distributed throughout the ceramic paper structure. Ceramic papers containing 1.2 wt.% zeolite after calcination at 650°C resulted in structured catalysts that were easy-to-handle, and which can be adapted to different conformations.

  6. Small strain deformation measurements of konjac glucomannan solutions and the influence of borate cross-linking.

    Ratcliffe, Ian; Williams, Peter A; English, Robert J; Meadows, John

    2013-06-01

    The dynamic rheology of aqueous solutions of konjac glucomannan has been evaluated over a range of concentrations up to 2.35%, and the effect of borate cross-linking of such solutions evaluated in the range 0.02-40 mM borate. In preliminary work, conventional parallel plate geometries were employed and in situ cross-linking was investigated. For borate cross-linked samples a superior method, however, was found to be measurement of pre-formed cores of cross-linked polymer into which a four-bladed vane geometry was introduced. In order to compare with other associating polymer systems, rheological data were analysed by defining plateau moduli, corresponding relaxation times and zero shear viscosities and the scaling behaviour of these parameters with polymer and cross-linker concentrations was established. Maxwell fits and time-concentration superposition procedures were investigated. The rheological properties of the cross-linked polymer were shown to be the result of both increased network connectivity and retarded network dynamics. PMID:23618269

  7. Thermal stability and spectroscopic properties of Ho3+doped tellurite-borate glasses

    杨艳民; 刘延洲; 蔡培庆; Ramzi Maalej; Hyo Jin Seo

    2015-01-01

    Ho3+ions doped tellurite-borate glass samples with varying compositions were prepared. The compositional dependence on phenomenological Judd-Ofelt parameters was compared in different kinds of rare earth ions doped tellurite-borate glasses. Two methods were used to obtain radiative transition probability of 5I7 level with the aim of assuring the fitting quality. The integral ab-sorption cross-sections and line shapes corresponding to 5I8→5G6 and 5I8→5I7 transition of Ho3+ions were investigated in tellurite-borate glasses. The obtained data indicated that the integral absorption cross-sections corresponding to 5I8→5G6 transition of Ho3+ions mainly depended on phenomenological Judd-Ofelt parameter,Ω2, because 5I8→5G6 transition belonged to hypersensitive transitions, which led to a largerΩ2 value. The change of line shapes of absorption spectra corresponding to 5I8→5G6 and 5I8→5I7 transitions of Ho3+ions came from the lower energy regions, which could be attributed to the changed distribution of Stark levels and thermal population.

  8. Decoupling of uranium metal with borated plaster using 252Cf nose analysis methods

    The use of borated plaster to isolate uranium (93.2 wt % 235U) metal was studied in a series of subcritical experiments with uranium metal cylinders (7.0 in. diam, 2.0 in. thick) and slabs (approx.1.4 x approx.5.4 x approx.10.1 in. dimensions). In the cylindrical experiments, the thickness of borated plaster was varied up to 10 in. and the subcriticality measured using the 252Cf-source-driven neutron noise analysis method. In the experiments with the uranium slabs, an array of slabs 3 wide and 8 high was assembled in steps to demonstrate the subcriticality of this array with 3.75-in.-thick borated plaster as an isolating material between all uranium slabs. In the slab experiments, both noise analysis and source neutron multiplication measurements were performed. Before assembly of the slab array the presence of boron in the plaster was verified by neutron transmission and gamma-ray spectrometry measurements

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

    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. PMID:16043053

  10. Microwave and conventional preparation of Zinc borate glass: Eu{sup 3+} ion as luminescent probe

    Mandal, Ashis K., E-mail: ashis@cgcri.res.in; Balaji, S., E-mail: sbalaji@cgcri.res.in; Sen, Ranjan, E-mail: rsen@cgcri.res.in

    2014-12-05

    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{sup 3+} to Eu{sup 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{sub 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{sub 2}O{sub 3} doped glass prepared in microwave heating indicates higher reduction of Eu{sup 3+} → Eu{sup 2+} than the glass melted in conventional route. Thus, microwave processing can be an alternative energy efficient, time saving, environmental friendly glass preparation method.

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

    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 Eu3+ to Eu2+ 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 (Tg) 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 Eu2O3 doped glass prepared in microwave heating indicates higher reduction of Eu3+ → Eu2+ than the glass melted in conventional route. Thus, microwave processing can be an alternative energy efficient, time saving, environmental friendly glass preparation method

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

    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 BO4 tetrahedra to BO3 tetragonal planar structure with increasing of the zinc oxide content. (author)

  13. Growth and characterization of a new non-linear optical tris lead tris barium borate (TLTBB) single crystal

    Research highlights: → Research in borate crystals remains strong to this date due to the commercial applications of these materials as laser hosts, non-linear optical (NLO) elements and in UV optics. → In the present work, an attempt has been made to grow a new mixed borate crystal with controlled and desirable composition, structure and properties. → This work deals with the growth of inorganic single crystal of tris lead tris barium borate (TLTBB) by conventional slow solvent evaporation method. → The crystal exhibits a high SHG efficiency among the available solution grown NLO crystals of borate family. - Abstract: The growth of a new inorganic non-linear optical (NLO) borate crystal, tris lead tris barium borate (TLTBB) material has been reported. Crystal of dimension up to 7 mm x 5 mm x 5 mm are obtained from its aqueous solution by slow solvent evaporation technique. The resulting crystal exhibits square shape morphology. The crystal structure and morphology of the grown crystal have been identified by single crystal X-ray diffraction analysis. The high-resolution X-ray diffraction (HRXRD) analysis of the sample indicates its moderate crystalline quality. The UV-vis-NIR spectrum of TLTBB reveals a wide optical transmission window with a low level of optical absorption in the entire visible region. The second harmonic generation (SHG) efficiency of the sample is found to be nearly three times that of the standard KDP and its laser damage threshold value is 1.32 GW cm-2. The TGA/DTA analysis confirms high thermal stability (775.25 deg. C) of the sample among the solution grown NLO borate crystals. The SEM micrograph of TLTBB indicates that the crystal is made up of rectangular blocks with step like patterns.

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

    Sathish, K.; Thirumaran, S.

    2015-08-01

    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.

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

    Sathish, K; Thirumaran, S

    2015-08-01

    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

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

    Philip D. Evans

    2015-01-01

    Full Text Available 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 this hypothesis and chemically register zinc in OSB using SEM-EDX. Zinc borate particles aggregated at the wood-adhesive interface in OSB, creating interrupted lines of zinc oriented in the x-y plane. Zinc borate particles were also found in the lumens of wood cells. Zinc was distributed throughout OSB, although slightly less was present in the core of the composite than in surface layers. A network of zinc remained in OSB after leaching in water. The resistance of zinc to leaching may be due to its incorporation in glue-lines within OSB, in addition to its low water-solubility. We conclude that X-ray micro-CT is a powerful tool for studying the distribution of zinc in OSB and other wood composites containing zinc borate.

  17. Behavior of borate complex anion on the stabilities and the hydrogen evolutions of ZnxCo3-xO4 decorated graphene

    Hao, Xuqiang; Jin, Zhiliang; Wang, Fang; Xu, Jing; Min, Shixiong; Yuan, Hong; Lu, Gongxuan

    2015-06-01

    The electron oscillation of borate complex anions in the borate solution was a very interesting peculiar phenomenon in the study of Solution Chemistry up to now. By means of borate complex anions addition, reacting system inertion and the electrons addition, based on the peculiar contribution of borate complex anions with an electron oscillation characters, the stabilities and the hydrogen evolutions of ZnxCo3-xO4 decorated graphene were greatly improved. Here, the photocatalytic activity was dependent on the synergetic effects of borate complex anions and graphene. The structure-activity relationships between the borate complex anions and the ZnxCo3-xO4 decorated grapheme were investigated. The borate complex anions can not only contribute to the more efficiently capture electrons from excited Eosin dye but also beneficial to the more efficiently transfer electrons to the decorated catalysts. So the charge separation and the electrons transfer were more efficient in the condition of the borate complex anions addition as supported by fluorescence studies. The synergetic effects between boron and grapheme were due to the double-pathway of synergetic effects for electrons transfer.

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

    Yomei Tokuda; Yuya Takahashi; Hirokazu Masai; Shunichi Kaneko; Yoshikatsu Ueda; Shigeto Fujimura; Toshinobu Yoko

    2015-01-01

    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 showe...

  19. Solidification of borate radioactive resins using sulfoaluminate cement blending with zeolite

    Highlights: ► Borate radioactive resins could be solidified using SAC blending with zeolite. ► Adding 5% zeolite reduced the leachability of Cs+ and Co2+. ► XRD results showed that B(OH)4− was incorporated into ettringite. - Abstract: The solidification of borate radioactive resins using sulfoaluminate cement (SAC) blending with zeolite was investigated, and the performance of SAC–zeolite matrix for immobilizing borate resin was evaluated based on the compressive strength, leachability and mineral phases of solidified waste forms. The experimental results showed that the 28 d compressive strength of resin SAC–zeolite waste forms was 18.8 MPa, the cemented waste forms meet the requirement of water, freezing, irradiation and impact resistance tests. The leaching processes of Cs+ and Co2+ were diffusion-limit step. The leachability of Cs+ was higher than Co2+ no matter what the matrix contained zeolite or not, but leachability of both cations was reduced by adding 5% zeolite. For SAC–zeolite matrix, the leaching rates of Cs+ and Co2+ were 6.40 × 10−5 cm/d and 1.62 × 10−7 cm/d, and the cumulative leaching fractions were 2.9 × 10−3 cm and 2.3 × 10−5 cm, respectively. The X-ray diffraction (XRD) analysis suggested that B(OH)4− was incorporated by substitution of SO4− in the crystalline structure of ettringite (3CaO·Al2O3·3CaSO4·32H2O).

  20. Compositional dependence of optical band gap and refractive index in lead and bismuth borate glasses

    Mallur, Saisudha B.; Czarnecki, Tyler; Adhikari, Ashish; Babu, Panakkattu K.

    2015-08-15

    Highlights: • Refractive indices increase with increasing PbO/Bi{sub 2}O{sub 3} content. • Optical band gap arises due to direct forbidden transition. • Optical band gaps decrease with increasing PbO/Bi{sub 2}O{sub 3} content. • New empirical relation between the optical band gap and the refractive index. - Abstract: We prepared a series of lead and bismuth borate glasses by varying PbO/Bi{sub 2}O{sub 3} content and studied refractive index and optical band gap as a function of glass composition. Refractive indices were measured very accurately using a Brewster’s angle set up while the optical band gaps were determined by analyzing the optical absorption edge using the Mott–Davis model. Using the Lorentz–Lorentz method and the effective medium theory, we calculated the refractive indices and then compared them with the measured values. Bismuth borate glasses show better agreement between the calculated values of the refractive index and experimental values. We used a differential method based on Mott–Davis model to obtain the type of transition and optical band gap (E{sub opt}) which in turn was compared with the value of E{sub opt} obtained using the extinction coefficient. Our analysis shows that in both lead and bismuth borate glasses, the optical band gap arises due to direct forbidden transition. With increasing PbO/Bi{sub 2}O{sub 3} content, the absorption edge shifts toward longer wavelengths and the optical band gap decreases. This behavior can be explained in terms of changes to the Pb−O/Bi−O chemical bonds with glass composition. We obtained a new empirical relation between the optical band gap and the refractive index which can be used to accurately determine the electronic oxide polarizability in lead and bismuth oxide glasses.

  1. Compositional dependence of optical band gap and refractive index in lead and bismuth borate glasses

    Highlights: • Refractive indices increase with increasing PbO/Bi2O3 content. • Optical band gap arises due to direct forbidden transition. • Optical band gaps decrease with increasing PbO/Bi2O3 content. • New empirical relation between the optical band gap and the refractive index. - Abstract: We prepared a series of lead and bismuth borate glasses by varying PbO/Bi2O3 content and studied refractive index and optical band gap as a function of glass composition. Refractive indices were measured very accurately using a Brewster’s angle set up while the optical band gaps were determined by analyzing the optical absorption edge using the Mott–Davis model. Using the Lorentz–Lorentz method and the effective medium theory, we calculated the refractive indices and then compared them with the measured values. Bismuth borate glasses show better agreement between the calculated values of the refractive index and experimental values. We used a differential method based on Mott–Davis model to obtain the type of transition and optical band gap (Eopt) which in turn was compared with the value of Eopt obtained using the extinction coefficient. Our analysis shows that in both lead and bismuth borate glasses, the optical band gap arises due to direct forbidden transition. With increasing PbO/Bi2O3 content, the absorption edge shifts toward longer wavelengths and the optical band gap decreases. This behavior can be explained in terms of changes to the Pb−O/Bi−O chemical bonds with glass composition. We obtained a new empirical relation between the optical band gap and the refractive index which can be used to accurately determine the electronic oxide polarizability in lead and bismuth oxide glasses

  2. A Combined Lithium Borate and Lithium Fluoride Thermoluminescence Dosimeter for Routine Personal Monitoring

    Hot-pressed, 25 mg lithium-7 fluoride dosimeters (Harshaw) and sintered, 25 mg lithium borate dosimeters were compared and studied for application to routine personal monitoring. The lithium borate phosphor was prepared at Risö from lithium tetraborate with small additions of manganese and quartz and it was formed into tablets by means of an automatic tabletting machine. The sensitivity ratio LiF/Li2B4O7:Mn, Si was measured to be 3/1 with an Sb/Cs photomultiplier tube. The study of the two dosimeter types covered fading, annealing requirements, energy dependence on photon and beta radiation, re-use, neutron sensitivity, sensitivity to light, precision of low-dose measurements, etc. Plastic capsules each containing two 7LiF and two Li2B4O7: Mn, Si dosimeters were worn as personal dosimeters, In addition to their film dosimeters, by people working in reactor facilities and other areas. Good agreement between the two types of TL dosimeters was obtained for dose measurements in neutron-free areas. In reactor buildings a small overdose effect caused by neutrons was shown by the borate. The data showed poor agreement between TL and film dosimeters. A personnel dosimetry system consisting of two Li2B4O7: Mn dosimeters for normal routine beta and gamma monitoring and one 7L1F dosimeter used as a long-term dosimeter and as a safeguard against false readings due to thermal neutrons seems to make the most of the advantages of both Li2B4O7:Mn (low production cost, no annealing requirements after the read-out process) and 7LiF (no fading, good accuracy, low sensitivity to thermal neutrons). The three dosimeteis were assembled In a badge intended for routine personal monitoring, and the system was investigated for its energy and angular dependence with photon and beta radiation. (author)

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

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

    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 ...

  4. Electrochromic characteristics of a nickel borate thin film investigated by in situ XAFS and UV/vis spectroscopy

    The electrochromic transition of a nickel borate thin film between colorless and brown was examined by means of in situ XAFS and UV/vis spectroscopy. The XAFS spectra showed that the average valence state of the nickel species in the film changed from +2.1 to +3.8 following the application of an electrode potential. Additionally, a broad peak at 700 nm was observed during in situ UV/vis absorption measurements on the application of a positive potential. These results suggest that the nickel borate film reversibly forms a NiOOH structure with a domain size of several nanometers during the electrochromic reaction. (author)

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

    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.

  6. Molecular dynamics simulations of silicate and borate glasses and melts : structure, diffusion dynamics and vibrational properties

    Scherer, Christoph

    2015-01-01

    Molecular dynamics simulations of silicate and borate glasses and melts: Structure, diffusion dynamics and vibrational properties. In this work computer simulations of the model glass formers SiO2 and B2O3 are presented, using the techniques of classical molecular dynamics (MD) simulations and quantum mechanical calculations, based on density functional theory (DFT). The latter limits the system size to about 100−200 atoms. SiO2 and B2O3 are the two most important network formers for industri...

  7. General chemistry division. Quarterly report, January-April 1979. [Tricresyl borate

    Harrar, J. (ed.)

    1979-06-18

    The following were studied: scavenging behavior of NO/sub 3//sup -/ and methyl viologen, fluorescent lifetimes of dibromobimane and thiols, spectral determination of tricresyl borate, salicylaldehyde method for differentiation of primary and secondary amines, ammonia-gas-sensing electrodes, automated manometric CHN analyzer, computer program for calibration of graphite furnace atomic absorption spectrophotometer, contamination of alumina insulator, organic additives for stabilizing colloidal silica in hypersaline geothermal brine, x-ray fluorescence analysis of geological samples, dissolution of geothermal scale, and characterization of enzyme-catalyzed reactions (alkaline phosphatase). (DLC)

  8. Structural, optical and microhardness studies of pure and lanthanum doped ammonium penta borate (APB) single crystals

    Rare earth metal doped ammonium penta borate (MB) single crystals has been synthesized from slow solvent evaporation technique. The grown crystal has been subjected to single crystal X-ray diffraction analysis to identify the cell parameters and corresponding crystal system. The presence of lanthanum is confirmed by ICP analysis. The Kurtz's-Perry powder SHG efficiency was determined for both pure and lanthanum doped APB crystals as 1.6 and 2.2 times than that of pure KDP. The creation of weak lattice stress is confirmed by Vicker's microhardness test. (author)

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

    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 in the...... normal dispersion regime of BBO through a negative cascaded quadratic nonlinearity. Using pump wavelengths from 1.24 to 1.4 μm, dispersive waves are found from 1.9 to 2.2 μm, agreeing well with calculated resonant phasematching wavelengths due to degenerate four-wave mixing to the soliton. We also...

  10. Three-wave mixing mediated femtosecond pulse compression in β-barium borate.

    Grün, A; Austin, Dane R; Cousin, Seth L; Biegert, J

    2015-10-15

    Nonlinear pulse compression mediated by three-wave mixing is demonstrated for ultrashort Ti:sapphire pulses in a type II phase-matched β-barium borate (BBO) crystal using noncollinear geometry. 170 μJ pulses at 800 nm with a pulse duration of 74 fs are compressed at their sum frequency to 32 fs with 55 μJ of pulse energy. Experiments and computer simulations demonstrate the potential of sum-frequency pulse compression to match the group velocities of the interacting waves to crystals that were initially not considered in the context of nonlinear pulse compression. PMID:26469593

  11. Nouveaux complexes borates fluorescents : synthèses, propriétés et applications

    Frath, Denis

    2013-01-01

    Les travaux réalisés aux cours de cette thèse ont portés sur la création de nouveaux complexes borates fluorescents. Des voies de synthèse relativement simples et efficaces ont permis d'accéder à deux nouvelles familles de fluorophores : les Boranils et les Boricos. Les Boranils présentent des coefficients d'absorption molaire élevés, des rendements quantiques pouvant atteindre 90% et la capacité à agir comme antenne efficace pour du transfert d'énergie photoinduit. De nombreuses modification...

  12. Improved luminescent properties of novel nanostructured Eu3+ doped yttrium borate synthesized with carbon nanotube templates

    Graphical abstract: The activation spectra (a and c) measured by monitoring the 627 nm emission of Eu3+ and emission spectra (c and d) measured under λex = 247 nm. Figures (a) and (b) show the results for the sample annealed at 1000 °C without carbon nano-tube templates during synthesis. Figures (c) and (d) show the results for the sample annealed at 1000 °C with carbon nano-tube templates during synthesis. Compared with the sample without additive carbon nano-tube during synthesis, the sample with carbon nano-tube exhibited an extra excitation band at 281 nm, the intensity ratio between red (5D0−7F2) and orange (5D0−7F1) was increased from 1.1 to 3.66, and the CIE coordination changed from (0.655, 0.346) to (0.67, 0.33) (almost the same as that (0.665, 0.334) for commercial red phosphors Y2O2S:Eu3+, satisfying the requirement for red phosphors). These results indicate that the luminescent properties can be improved by carbon nano-tube template, which to our knowledge has not been reported before. Highlights: • Carbon nano-tube templates can significantly affect the morphology and enlarge the surface of the final samples. • The color purity can be greatly improved by carbon nano-tube templates. • Template-assisted samples exhibit extra Eu3+−O2− excitation band due to the surface effect. -- Abstract: Eu3+-doped yttrium borate samples were prepared via a hydrothermal method using borate or tributyl borate as B3+ sources, with and without carbon nanotubes as templates. The morphology of the samples is easily altered by varying the carbon nanotube template, B3+ source and post-annealing treatment. Photoluminescence measurements indicate that the color purity of samples is clearly improved by template-assisted synthesis. Furthermore, with tributyl borate as the B3+ source, CIE coordinates of (0.67, 0.33), very similar to the (0.665, 0.334) coordinates for the commercial red phosphor Y2O2S:Eu3+, can be obtained. Finally, an extra Eu3+−O2− excitation

  13. The new silver borate Ag{sub 3}B{sub 5}O{sub 9}

    Sohr, Gerhard; Falkowski, Viktoria; Huppertz, Hubert, E-mail: hubert.huppertz@uibk.ac.at

    2015-05-15

    Single crystals of Ag{sub 3}B{sub 5}O{sub 9} were obtained via high-pressure synthesis at 3 GPa and 600 °C, using a Walker-type multianvil high-pressure device. Ag{sub 3}B{sub 5}O{sub 9} crystalizes with a=674.7(2), b=943.5(2), c=1103.5(2) pm, V=0.7025(2) nm{sup 3}, and Z=4 in the noncentrosymmetric space group P2{sub 1}2{sub 1}2{sub 1} (no. 19). The orthorhombic structure was refined from 3740 independent reflections with R1=0.0496 and wR2=0.587 (all data). It is built up from infinite corner-sharing chains of BO{sub 4} tetrahedra along the a axis, which are interconnected by BO{sub 3} groups to form a network. In the structure, three crystallographically independent sites are occupied with Ag{sup +} cations exhibiting argentophillic interactions. The synthetic conditions as well as the results of the single crystal structure analysis are presented. - Graphical abstract: Noncentrosymmetric silver borate: During investigations in the system Ag–B–O, a new noncentrosymmetric silver borate Ag{sub 3}B{sub 5}O{sub 9} was discovered. The new structure type is built up from corner-sharing BO{sub 3} and BO{sub 4} groups, forming a network. Argentophillic interactions are clearly indicated by the Ag{sup +}⋯Ag{sup +} distances present in the structure. - Highlights: • A noncentrosymmetric borate Ag{sub 3}B{sub 5}O{sub 9} is accessible via high-pressure synthesis. • Ag{sub 3}B{sub 5}O{sub 9} is the second high-pressure silver borate. • Ag{sup +}⋯Ag{sup +} distances in Ag3B5O9 clearly indicate the presence of argentophillic interactions.

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

    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.

  15. Cobalt tris(mercaptoimidazolyl)borate complexes: synthetic studies and the structure of the first cobaltaboratrane.

    Mihalcik, David J; White, Jennifer L; Tanski, Joseph M; Zakharov, Lev N; Yap, Glenn P A; Incarvito, Christopher D; Rheingold, Arnold L; Rabinovich, Daniel

    2004-05-21

    The paramagnetic complexes (TmtBu)CoX (X = Cl, Br, I) have been readily prepared and structurally characterized and provide a convenient entry into cobalt(II) tris(mercaptoimidazolyl)borate chemistry. A number of derivatives, including mononuclear triphenylphosphine adducts [(TmtBu)Co(PPh3)]X and dinuclear compounds [Co2(TmtBu)2X]Y, have been prepared in order to ascertain whether cobalt is a reliable surrogate for zinc in biological systems, particularly in sulfur-rich coordination environments. The structure of the first cobaltaboratrane is also reported. PMID:15252613

  16. Effect of zinc borate on the thermal degradation of ammonium polyphosphate

    The thermal behaviour of a mixture containing an ammonium polyphosphate based compound (AP760) and zinc borate (ZB) is investigated. After an investigation of the degradation of the pure components, the interactions between them are examined by thermogravimetry. Then, X-ray diffraction (XRD) and 11B and 31P solid-state nuclear magnetic resonance (NMR) measurements have been carried out on residues of mixtures of AP760 and FBZB heat treated at different characteristic temperatures. It reveals the nature of the interactions taking place between the two components. It is demonstrated that reactions lead to the formation of zinc phosphate and of borophosphates. Mechanisms of thermal degradation are proposed

  17. Optical properties of Dy3+ doped bismuth zinc borate glass and glass ceramics

    Shanmugavelu, B.; Kanth Kumar, V. V. Ravi

    2012-06-01

    Dy3+ doped bismuth zinc borate transparent glasses were prepared by melt quenching technique and these glasses were used precursor to obtain transparent glass ceramics by heat treatment method. XRD pattern of the glass ceramic shows the formation of the β-BiB3O6 and Bi2ZnOB2O6 phases. The visible emission intensity of the glass ceramics is stronger than the glass. This can be due to the formation of nano nonlinear optical crystallites in glass matrix.

  18. LaZnB(5)O(10), the first lanthanum zinc borate.

    Jiao, Zhi-Wei; Wang, Ru-Ji; Wang, Xiao-Qing; Shen, De-Zhong; Shen, Guang-Qiu

    2009-01-01

    Lanthanum zinc penta-borate, LaZnB(5)O(10), was synthesized by flux-supported solid-state reaction. It is a member of the LnMB(5)O(10) (Ln = rare earth ion and M = divalent metal ion) structure type. The crystal shows a three-dimensional structure constructed from two-dimensional {[B(5)O(10)](5-)}(n) layers with the lanthanum (coordination number nine) and zinc (coordination number six) ions filling in the inter-layers. PMID:21579905

  19. Durability and shielding performance of borated Ceramicrete coatings in beta and gamma radiation fields

    Highlights: • It incorporates all suggestions by the reviewers. • Explanation to each new term is provided and suitable references are given. • Sample identities have been streamlined by revising the text and the tables. • Some figures have been redrawn. - Abstract: Ceramicrete™, a chemically bonded phosphate ceramic, was developed for nuclear waste immobilization and nuclear radiation shielding. Ceramicrete products are fabricated by an acid–base reaction between magnesium oxide and mono potassium phosphate. Fillers are used to impart desired properties to the product. Ceramicrete’s tailored compositions have resulted in several commercial structural products, including corrosion- and fire-protection coatings. Their borated version, called Borobond™, has been studied for its neutron shielding capabilities and is being used in structures built for storage of nuclear materials. This investigation assesses the durability and shielding performance of borated Ceramicrete coatings when exposed to gamma and beta radiations to predict the composition needed for optimal shielding performance in a realistic nuclear radiation field. Investigations were conducted using experimental data coupled with predictive Monte Carlo computer model. The results show that it is possible to produce products for simultaneous shielding of all three types of nuclear radiations, viz., neutrons, gamma-, and beta-rays. Additionally, because sprayable Ceramicrete coatings exhibit excellent corrosion- and fire-protection characteristics on steel, this research also establishes an opportunity to produce thick coatings to enhance the shielding performance of corrosion and fire protection coatings for use in high radiation environment in nuclear industry

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

    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.

  1. Structures of potassium, sodium and lithium bis(oxalato)borate salts from powder diffraction data

    The crystal structures of the alkali-metal bis(oxalato)borate salts A[B(C2O4)2] (A = K, Na, Li) have been determined ab initio using powder diffraction data obtained from a laboratory diffractometer. The K compound crystallizes in the orthorhombic space group Cmcm and its structure has been solved by direct methods applied to the integrated intensities from full pattern decomposition. The Na compound is isostructural with the K salt, while the crystal structure of the highly hydroscopic Li compound differs from the other two. It has an orthorhombic lattice, space group Pnma, and its structure was solved by the global optimization method using a parallel tempering approach. In the K and Na structures the metal ions and complex borate ions form chains with m2m symmetry. Metal-oxygen bonding between the chains links them into a layer and then a framework with square tunnels. The coordination number of both K and Na is eight. The Li compound also contains chains that have.m. symmetry and are bound together into a three-dimensional framework. The coordination polyhedron of the Li atom is a square pyramid with Li lying in its base. This square pyramidal coordination leads to its high reactivity with moisture to give Li[B(C2O4)2]H2O with lithium in six coordination. (orig.)

  2. Development of biomimetic coatings on Sm oxide doped ELB (Eu-Li-borate) glasses

    The in-vitro biomineralization of Eu/Li-borate glasses containing Sm2O3 was investigated by immersion in simulated body fluid (SBF) up to 72 h. Back scattering scanning electron microscope supplemented with EDX was used to follow the development of the phosphatic layer post 72 h SBF immersion. Biochemical analyses of calcium and inorganic phosphorus (Ca2+ and iP) ions were conducted using relevant biochemical kits and spectrophotometer. Spectra of TF-X-ray analyses and Fourier transform infrared were obtained for the samples post 72 h immersion and compared to the host one. The role of Sm2O3 in the biomineralization and crystallinity of the (ELB) borate glasses is proved by the developed rounded nano particles and the presence of elemental Eu and Sm in the formed layer beside Ca and P as presented by EDX. The continuous reduced values of ionic iP accompanying the adsorption and release of Ca ions in SBF with time assured the biolayer formation. The formed phosphatic layer presented shifted XRD peaks due to ionic incorporations especially of Sm3+. FT-IR proved the selectivity of BO3 group for phosphatic deposition. Deconvolution of ν4 and ν3 regions, for carbonates and phosphates, respectively, proved the enhanced peak areas with increased Sm3+ content.

  3. Durability and shielding performance of borated Ceramicrete coatings in beta and gamma radiation fields

    Wagh, Arun S.; Sayenko, S. Yu.; Dovbnya, A. N.; Shkuropatenko, V. A.; Tarasov, R. V.; Rybka, A. V.; Zakharchenko, A. A.

    2015-07-01

    Ceramicrete™, a chemically bonded phosphate ceramic, was developed for nuclear waste immobilization and nuclear radiation shielding. Ceramicrete products are fabricated by an acid-base reaction between magnesium oxide and mono potassium phosphate. Fillers are used to impart desired properties to the product. Ceramicrete's tailored compositions have resulted in several commercial structural products, including corrosion- and fire-protection coatings. Their borated version, called Borobond™, has been studied for its neutron shielding capabilities and is being used in structures built for storage of nuclear materials. This investigation assesses the durability and shielding performance of borated Ceramicrete coatings when exposed to gamma and beta radiations to predict the composition needed for optimal shielding performance in a realistic nuclear radiation field. Investigations were conducted using experimental data coupled with predictive Monte Carlo computer model. The results show that it is possible to produce products for simultaneous shielding of all three types of nuclear radiations, viz., neutrons, gamma-, and beta-rays. Additionally, because sprayable Ceramicrete coatings exhibit excellent corrosion- and fire-protection characteristics on steel, this research also establishes an opportunity to produce thick coatings to enhance the shielding performance of corrosion and fire protection coatings for use in high radiation environment in nuclear industry.

  4. Luminescent borate glass for efficiency enhancement of CdTe solar cells

    Steudel, Franziska, E-mail: franziska.steudel@iwmh.fraunhofer.de [Fraunhofer Application Center for Inorganic Phosphors, Branch Lab of Fraunhofer Institute for Mechanics of Materials IWM, Lübecker Ring 2, 59494 Soest (Germany); Loos, Sebastian [Department of Electrical Engineering, South Westphalia University of Applied Sciences, Lübecker Ring 2, 59494 Soest (Germany); Ahrens, Bernd; Schweizer, Stefan [Fraunhofer Application Center for Inorganic Phosphors, Branch Lab of Fraunhofer Institute for Mechanics of Materials IWM, Lübecker Ring 2, 59494 Soest (Germany); Department of Electrical Engineering, South Westphalia University of Applied Sciences, Lübecker Ring 2, 59494 Soest (Germany)

    2015-08-15

    Rare-earth (RE) doped borate glasses are investigated for their potential as photon down-shifting cover glass for CdTe solar cells. The barium borate base glass is doped with trivalent rare-earth ions such as Sm{sup 3+}, Eu{sup 3+}, and Tb{sup 3+} showing an intense luminescence in the red (Sm{sup 3+}, Eu{sup 3+}) and green (Tb{sup 3+}) spectral range upon excitation in the ultraviolet and blue. Additionally, the glasses are double-doped with two RE ions for a broad-band absorption. The gain in short-circuit current density of CdTe solar cells with different thicknesses of the CdS buffer layer is calculated. Though the single-doped glasses already reveal a slight increase in short-circuit current density, the double-doped glasses allow for higher efficiency gains since a significant broader spectral range is covered for absorption. For a Tb{sup 3+}/Eu{sup 3+} double-doped glass with a RE doping level of 1 at% each, an efficiency increase of 1.32% can be achieved. - Highlights: • Rare-earth doped front glass for high efficiency CdTe solar cells were prepared. • Double-doping allows for higher efficiency gains than single-doping. • Efficiency enhancement of 1.32% can be achieved with Tb{sup 3+}/Eu{sup 3+} doped front glass.

  5. Luminescent borate glass for efficiency enhancement of CdTe solar cells

    Rare-earth (RE) doped borate glasses are investigated for their potential as photon down-shifting cover glass for CdTe solar cells. The barium borate base glass is doped with trivalent rare-earth ions such as Sm3+, Eu3+, and Tb3+ showing an intense luminescence in the red (Sm3+, Eu3+) and green (Tb3+) spectral range upon excitation in the ultraviolet and blue. Additionally, the glasses are double-doped with two RE ions for a broad-band absorption. The gain in short-circuit current density of CdTe solar cells with different thicknesses of the CdS buffer layer is calculated. Though the single-doped glasses already reveal a slight increase in short-circuit current density, the double-doped glasses allow for higher efficiency gains since a significant broader spectral range is covered for absorption. For a Tb3+/Eu3+ double-doped glass with a RE doping level of 1 at% each, an efficiency increase of 1.32% can be achieved. - Highlights: • Rare-earth doped front glass for high efficiency CdTe solar cells were prepared. • Double-doping allows for higher efficiency gains than single-doping. • Efficiency enhancement of 1.32% can be achieved with Tb3+/Eu3+ doped front glass

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

    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.

  7. Durability and shielding performance of borated Ceramicrete coatings in beta and gamma radiation fields

    Wagh, Arun S., E-mail: asw@anl.gov [Environmental Science Division, Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439 (United States); Sayenko, S.Yu.; Dovbnya, A.N.; Shkuropatenko, V.A.; Tarasov, R.V.; Rybka, A.V.; Zakharchenko, A.A. [National Science Center, Kharkov Institute of Physics and Technology, Kharkov (Ukraine)

    2015-07-15

    Highlights: • It incorporates all suggestions by the reviewers. • Explanation to each new term is provided and suitable references are given. • Sample identities have been streamlined by revising the text and the tables. • Some figures have been redrawn. - Abstract: Ceramicrete™, a chemically bonded phosphate ceramic, was developed for nuclear waste immobilization and nuclear radiation shielding. Ceramicrete products are fabricated by an acid–base reaction between magnesium oxide and mono potassium phosphate. Fillers are used to impart desired properties to the product. Ceramicrete’s tailored compositions have resulted in several commercial structural products, including corrosion- and fire-protection coatings. Their borated version, called Borobond™, has been studied for its neutron shielding capabilities and is being used in structures built for storage of nuclear materials. This investigation assesses the durability and shielding performance of borated Ceramicrete coatings when exposed to gamma and beta radiations to predict the composition needed for optimal shielding performance in a realistic nuclear radiation field. Investigations were conducted using experimental data coupled with predictive Monte Carlo computer model. The results show that it is possible to produce products for simultaneous shielding of all three types of nuclear radiations, viz., neutrons, gamma-, and beta-rays. Additionally, because sprayable Ceramicrete coatings exhibit excellent corrosion- and fire-protection characteristics on steel, this research also establishes an opportunity to produce thick coatings to enhance the shielding performance of corrosion and fire protection coatings for use in high radiation environment in nuclear industry.

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

    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.

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

    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. PMID:20057014

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

    Liu Xin; Huang Wenhai [Institute of Bioengineering and Information Technology Materials, Tongji University, Shanghai 200092 (China); Pan Haobo [Department of Orthopaedics and Traumatology, University of Hong Kong, 999077 (Hong Kong); Fu Hailuo; Fu Qiang; Rahaman, Mohamed N, E-mail: tsliuxin@hotmail.co, E-mail: whhuang@tongji.edu.c [Department of Materials Science and Engineering, and Center for Bone and Tissue Repair and Regeneration, Missouri University of Science and Technology, MO 65409 (United States)

    2010-02-15

    Porous scaffolds of a borate-based glass (composition in mol%: 6Na{sub 2}O, 8K{sub 2}O, 8MgO, 22CaO, 36B{sub 2}O{sub 3}, 18SiO{sub 2}, 2P{sub 2}O{sub 5}), with interconnected porosity of {approx}70% and pores of size 200-500{mu}m, 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 K{sub 2}HPO{sub 4} solution (starting pH = 7.0) at 37 deg. 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.

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

    The inorganic pigments malachite, Egyptian blue, Ercolano blue and chrome yellow have been doped with the neutral homoleptic Ln(III) complex Ln(Tp)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. Optical and Physical Properties of Bismuth Borate Glasses Doped With Dy3+

    P. Limsuwan

    2011-01-01

    Full Text Available This study reports on physical and optical properties of Dy3+ doped bismuth borate glass. The glasses containing Dy3+ in (70-xB2O3:30Bi2O3:xDy2O3 (where x = 0.0-2.5 mol% have been prepared by melt-quenching method. In order to understand the role of Dy2O3 in these glasses, the density, molar volume and optical spectra were investigated. The results show that molar volume of the glasses increase with the increasing of Dy2O3 concentration and consequently generating more non-bridging oxygen (NBOs into glass matrix. The absorption spectra of Dy3+ doped in bismuth borate glass correspond with several bands, which are assigned from the ground state, 6H15/2 to 6F3/2(761 nm, 6F5/2(806 nm, 6F7/2(907 nm, (6H7/2, 6F9/2(1099 nm, (6F11/2, 6H9/2 (1283 nm and 6H11/2(1695 nm. Moreover, the optical basicities were also theoretically determined.

  13. Study of Paramagnetic Species in γ-irradiated Lithium Borate Glasses Doped With Cu2+ Ions

    Mixed alkali borate glasses doped with different concentration of Cu O ranging from (0.1-10) wt% have been prepared by the melt quenching technique. The prepared samples were studied by means of density, molar volume, infrared spectroscopy and electron paramagnetic resonance (EPR) measurements before and after successive gamma irradiation (50-200 kGy). The results showed that the density increase while molar volume decrease with the increase of CuO %. The infrared absorption studies revealed that structure of the glass network consists of BO 3 , BO 4 and B-O-Cu linkages. Gamma irradiation causes minor changes in the IR spectral bands which are related to the bond break of the B-O bond and formation non-bridging oxygen. Gamma irradiation causes irregular change in the intensities of the EPR spectra for samples doped with 0.1, 0.2 and 10 wt % of Cu O, however, no change in the EPR spectra of 2 and 5 wt % of Cu O for all absorbed doses (50-200 kGy). It is expected that the Cu-doped lithium borate glass 2 and 5 wt % of Cu O may be used for radiation shielding.

  14. New Routes to a Series of σ-Borane/Borate Complexes of Molybdenum and Ruthenium.

    Ramalakshmi, Rongala; Saha, Koushik; Roy, Dipak Kumar; Varghese, Babu; Phukan, Ashwini K; Ghosh, Sundargopal

    2015-11-23

    A series of agostic σ-borane/borate complexes have been synthesized and structurally characterized from simple borane adducts. A room-temperature reaction of [Cp*Mo(CO)3 Me], 1 with Li[BH3 (EPh)] (Cp*=pentamethylcyclopentadienyl, E=S, Se, Te) yielded hydroborate complexes [Cp*Mo(CO)2 (μ-H)BH2 EPh] in good yields. With 2-mercapto-benzothiazole, an N,S-carbene-anchored σ-borate complex [Cp*Mo(CO)2 BH3 (1-benzothiazol-2-ylidene)] (5) was isolated. Further, a transmetalation of the B-agostic ruthenium complex [Cp*Ru(μ-H)BHL2 ] (6, L=C7 H4 NS2 ) with [Mn2 (CO)10 ] affords a new B-agostic complex, [Mn(CO)3 (μ-H)BHL2 ] (7) with the same structural motif in which the central metal is replaced by an isolobal and isoelectronic [Mn(CO)3 ] unit. Natural-bond-orbital analyses of 5-7 indicate significant delocalization of the electron density from the filled σBH orbital to the vacant metal orbital. PMID:26450356

  15. Theoretical survey of the ligand tunability of poly(azolyl)borates.

    Lu, Dongmei; Tang, Huarong

    2015-07-14

    Using density functional calculations, we have systematically investigated a series of homoleptic poly(azolyl)borate ligands, which display unusual steadily declining bond strengths accompanied by bond contractions when the azolyl groups are sequentially substituted to the parent BH4(-). As ligands, their effects on the coordinated metal ions (Cu(i) and Mo(0)) are quantitatively represented by two ligand tunability descriptors: the vibration frequency (νCO) of the CO groups complexed to the metal ions and the charge of the metal-(CO)x moiety, between which a good linear correlation exists. For the same number of azolyl substitutions, the boundary of ligand tunability is always marked by the pyrazolyl and tetrazolyl groups at the two ends, which feature the lowest and the highest nitrogen content in the azolyl ring, respectively. With the increase of the azolyl substitution number in the borate ligands, the νCO range expands, indicating a higher tunability of the ligands. The type of metal ion and the charge they carry play minor roles in influencing the ligand tunability. PMID:26062889

  16. Green-emitting nanoscaled borate phosphors Sr3RE2(BO3)4:Tb3+

    Three Tb3+ doped mixed strontium – rare earths borate phosphors of general formula Sr3RE2(BO3)4:Tb3+ (RE = Y, La or Gd) of 25–40 nm particle size were obtained by the Pechini sol–gel method, using citric acid and ethylene glycol as gel-forming agents. The structures of prepared materials were confirmed and characterized using X-ray powder diffraction and transmission electron microscopy. Photoluminescence properties, such as emission and excitation spectra and luminescence lifetimes of the phosphors, were measured. Excitation of the phosphors using different wavelengths in the UV range is possible. Lifetimes measured for the phosphors ranged from 2.2 to 2.7 ms. All of the Tb3+-doped phosphors show excellent luminescent properties, with a bright emission of green light under UV excitation. The color coordinates of emitted light on CIE1931 chromaticity diagram are close to those of National Television Standards Committee (NTSC) standard of green. - Graphical abstract: Display Omitted - Highlights: • Mixed strontium-rare earths borate Tb3+-doped nanoluminophors were obtained for the first time. • Optimal conditions for the synthesis of Sr3RE2(BO3)4:Tb3+ were found. • Photoluminescence properties of well-emitting products are discussed. • The color CIE coordinates of the nanosized (40 nm) particles were determined

  17. Spectral signatures of spin–phonon and electron–phonon interactions in multiferroic iron borates

    Popova, M.N., E-mail: popova@isan.troitsk.ru [Institute of Spectroscopy, RAS, Moscow, Troitsk 142190 (Russian Federation); Boldyrev, K.N.; Klimin, S.A. [Institute of Spectroscopy, RAS, Moscow, Troitsk 142190 (Russian Federation); Stanislavchuk, T.N.; Sirenko, A.A. [Department of Physics, New Jersey Institute of Technology, Newark, NJ 07102 (United States); Bezmaternykh, L.N. [Kirenskiy Institute of Physics, Siberian Branch of RAS, Krasnoyarsk 660036 (Russian Federation)

    2015-06-01

    High-resolution far-infrared reflection and polarized ellipsometry, as well as Raman scattering temperature-dependent measurements are used to study spin-phonon and electron-phonon interactions in rare-earth (RE) iron borates with the R32 structure of a natural mineral huntite, namely, in RFe{sub 3}(BO{sub 3}){sub 4} with R=Pr, Nd, and Sm. Pronounced peculiarities in the ω(T) dependences at the Néel temperature T{sub N}≈32 K are observed for all the compounds studied and the origin of these peculiarities is discussed. A coupling between lattice phonons and crystal-field excitations of a RE ion manifests itself by a renormalization of frequencies and intensities of coupled modes. Modeling of the spectra has revealed the value of about 15 cm{sup −1} for the electron–phonon coupling constant in PrFe{sub 3}(BO{sub 3}){sub 4}. - Highlights: • Rare-earth iron borates exhibit peculiarities in the phonon frequencies at T{sub N}. • We propose mechanisms of the spin-phonon coupling in RFe{sub 3}(BO{sub 3}){sub 4}. • A coupling of phonons and crystal-field excitations manifests itself in the spectra. • The electron-phonon coupling constant for PrFe{sub 3}(BO{sub 3}){sub 4} amounts to 14.6 cm{sup −1}.

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

    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 (13C and 11B), 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

  19. Cerium luminescence in borate glass and effect of aluminium on blue green emission of cerium ions

    CeO2 doped lead borate (CE) and lead alumino borate (CEA) glasses are prepared by melt quench method at high temperature. The main luminescence band of 5d–4f transition of Ce3+ ions with maxima at around 489 nm of Ce3+ ions in these glasses has been observed, along with red shift and larger stokes shift, which shows that the covalency of the rare earth to oxygen bond increases with the increase in CeO2 content at the expense of Al2O3. Shifting of UV absorption edge towards longer wavelength and a decrease in band gap with increase in CeO2 concentration in both the glass systems has been observed. Moreover densification and stabilization of glass network has been observed which is due to conversion of BO3 units to more compact and stable BO4 units. This covalency effect and the formation of BO4 groups with addition of CeO2 and incorporation of Al2O3 content are responsible for clear effect on luminescence of the present glass system. Moreover the optical basicity values were theoretically determined along with density and molar volume. -- Highlights: • Aluminium incorporation assists in dispersing the clusters of cerium ions and thus enhancing luminescence response. • Decrease of optical band gap energy with an increase of cerium concentration shows the semiconducting behavior. • Larger stokes shift shows that the covalency of rare earth to oxygen bond increases with increase in CeO2

  20. Spectral signatures of spin–phonon and electron–phonon interactions in multiferroic iron borates

    High-resolution far-infrared reflection and polarized ellipsometry, as well as Raman scattering temperature-dependent measurements are used to study spin-phonon and electron-phonon interactions in rare-earth (RE) iron borates with the R32 structure of a natural mineral huntite, namely, in RFe3(BO3)4 with R=Pr, Nd, and Sm. Pronounced peculiarities in the ω(T) dependences at the Néel temperature TN≈32 K are observed for all the compounds studied and the origin of these peculiarities is discussed. A coupling between lattice phonons and crystal-field excitations of a RE ion manifests itself by a renormalization of frequencies and intensities of coupled modes. Modeling of the spectra has revealed the value of about 15 cm−1 for the electron–phonon coupling constant in PrFe3(BO3)4. - Highlights: • Rare-earth iron borates exhibit peculiarities in the phonon frequencies at TN. • We propose mechanisms of the spin-phonon coupling in RFe3(BO3)4. • A coupling of phonons and crystal-field excitations manifests itself in the spectra. • The electron-phonon coupling constant for PrFe3(BO3)4 amounts to 14.6 cm−1

  1. Role of electron transfer in Ce3+ sensitized Yb3+ luminescence in borate glass

    In a Ce3+-Yb3+ system, two mechanisms are proposed so far namely, the quantum cutting mechanism and the electron transfer mechanism explaining Yb3+ infrared luminescence under Ce3+ excitation. Among them, the quantum cutting mechanism, where one Ce3+ photon (ultraviolet/blue) gives rise to two Yb3+ photons (near infrared) is widely sought for because of its huge potential in enhancing the solar cell efficiency. In present study on Ce3+-Yb3+ codoped borate glasses, Ce3+ sensitized Yb3+ luminescence at ∼1 μm have been observed on Ce3+ 5d state excitation. However, the intensity of sensitized Yb3+ luminescence is found to be very weak compared to the strong quenching occurred in Ce3+ luminescence in Yb3+ codoped glasses. Moreover, the absolute luminescence quantum yield also showed a decreasing trend with Yb3+ codoping in the glasses. The overall behavior of the luminescence properties and the quantum yield is strongly contradicting with the quantum cutting phenomenon. The results are attributed to the energetically favorable electron transfer interactions followed by Ce3+-Yb3+ ⇌ Ce4+-Yb2+ inter-valence charge transfer and successfully explained using the absolute electron binding energies of dopant ions in the studied borate glass. Finally, an attempt has been presented to generalize the electron transfer mechanism among opposite oxidation/reduction property dopant ions using the vacuum referred electron binding energy (VRBE) scheme for lanthanide series

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

    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. PMID:26706550

  3. Effect of copper oxide on structure and physical properties of lithium lead borate glasses

    Kashif, I.; Ratep, A.

    2015-09-01

    Copper-doped Lead lithium borate glass samples with the composition of (35- x) Pb3O4- xCuO-65Li2B4O7, where x = 5, 10, 15 or 20 mol%, have been prepared by melt quenching technique. Glass-forming ability, density, electrical conductivity, magnetic susceptibility and structural properties of lead lithium borate glasses have been investigated. IR spectroscopic data show that the copper ions play the role of glass modifier. Addition of CuO influences BO3 ↔ BO4 conversion. Density is expressed in terms of the structural modifications that take place in glass matrix. The increase in Tg reflects an increase in bond strength, and samples obtain more rigid glass structure. Electrical conductivity and magnetic susceptibility χ data show a variable behavior with the increase in the copper content in two valance states Cu+ and Cu+2. In addition, optical properties depend on the change of the role of copper ions in the samples' structure. Optical energy band gap E opt and Urbach energy E tail are determined. The increase in E opt and UV cutoff with an increase in CuO content is due to the decrease in non-bridging oxygen concentration. The decrease in E tail at higher concentrations is attributed to the copper ion accumulation in the interstitial positions and to the formation of orthoborate groups. These samples are suitable for the green light longpass filters.

  4. Moessbauer study of the fraction of non-bridging oxygens in potassium borate glasses

    A Moessbauer study was performed to find the fraction of non-bridging oxygens in potassium borate glasses containing a small amount of iron. The borate glasses with alkali contents of 15, 20, 25, 30 and 40 mol% were irradiated with 60Co-γ rays at room temperature in a nitrogen atmosphere. The Moessbauer absorption area for the irradiation-induced Fe2+ increased with the total γ-ray dose in the range of 1 x 106 - 2 x 108 R, and became constant after irradiation ranging from 2 x 108 R - 1 x 109 R. The absorption area for the Fe2+ at the saturated region was correlated with the difference in the glass structure, i.e., the fraction of the non-bridging oxygens was estimated from the increased absorption area for the Fe2+ as a function of the alkali content of the glasses. The fraction of the non-bridging oxygen increased with the alkali content of the glasses in the alkali region above 20 mol%, and about 14% of the fraction was obtained for an alkali content of 40 mol%. (orig.)

  5. Evaluation of hydroxyapatite coatings on borate passivated 316L SS in Ringer's solution

    Surgical grade stainless steel (316L SS) is one of the widely used implant material in orthopedic surgeries. But often the release of metal ions is evidenced from the implants and subsequently a second surgery is required to remove the implant material. One way to control this release of metal ions is to coat the implant material with a biocompatible material like hydroxyapatite. In this paper we have reported a successful coating of hydroxyapatite over borate passivated 316L SS by a dip coating method. The coatings were characterized by electrochemical techniques such as potentiodynamic polarization, electrochemical impedance and cyclic voltammetry (CV). Also X-ray diffraction (XRD) and scanning electron microscopic (SEM) studies were performed to confirm the quality of the coatings. Results of accelerated leach out characteristics by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and the evaluation of shear strength are also presented to support the corrosion resistant nature of the coatings. The enhanced bio-resistivity of the as-formed HAP coatings on passivated 316L SS is attributed to the protective passive layer formed by borate buffer solution at selected potentials.

  6. Enhanced ionic conductivity in borate ester plasticized Polyacrylonitrile electrolytes for lithium battery application

    The effect of low molecular weight borate ester on the ionic conductivity of polyacrylonitrile (PAN) was systematically investigated by means of measuring conductivity using the impedance technique. Gel polymer electrolyte (SPE) films consisting of PAN as host polymer, LiCF3SO3 and LiBF4 as ionic salts, and poly (ethylene glycol) borate ester (PEGB), ethylene carbonate/propylene carbonate (EC/PC) as plasticizers were prepared by physical blending method. All measurements were performed on electrolyte samples with various contents. Fourier transform infrared spectroscopy (FT-IR) gave evidence of the interactions among PAN, plasticizers and lithium salt. The surface morphology of the electrolytes was investigated by scanning electron microscopy (SEM). Thermal properties of these materials were searched with thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Conductivity studies of these blend polymer electrolytes were carried out in the temperature range 20–100 °C. The maximum ionic conductivity values of 1.8 × 10−3 and 1.4 × 10−4 S cm−1 were measured for the film containing 4PAN-10EC/PC-4LiBF4 and 4PAN-10PEGB-4LiCF3SO3, respectively, at room temperature. These films have a good conductivity, better dimensional stability and wide electrochemical stability window. These unique properties make the composite gel membranes suitable for application as electrolyte in rechargeable Li-ion batteries

  7. The structural, optical and magnetic parameter of manganese doped strontium zinc borate glasses

    Glasses with composition 10SrO:(30−x)ZnO:60B2O3:xMnO, 0≤x≤0.9 (all compositions in wt%) have been prepared and investigated by X-ray diffraction, EPR, Optical absorption and FT-IR spectroscopic techniques. The XRD pattern of all the glasses confirmed the formation of an amorphous structure. The EPR spectra of all glass samples exhibit resonance signals at g≈2.0 with a sextet of hyperfine lines. The spin concentration (N) and temperature dependence of EPR signals were studied for Mn2+ ions in strontium zinc borate glass samples. The zero-field splitting parameter D has been evaluated from the intensities of the allowed hyperfine lines. The paramagnetic susceptibility (χ) was calculated from EPR data at different temperatures and the Curie temperature (θp) was calculated from the 1/χ verses T graph. The optical absorption spectra exhibit a single broad band near 470 nm and this has been attributed to the spin-allowed 5Eg→5T2g transition of Mn3+ ions in octahedral symmetry. The theoretical optical basicity (Λth) of these glasses have also been evaluated. The FTIR studies show BO3 and BO4 structural units in strontium zinc borate glasses

  8. The structural, optical and magnetic parameter of manganese doped strontium zinc borate glasses

    Sumalatha, B.; Omkaram, I.; Rajavardhana Rao, T.; Linga Raju, Ch.

    2013-02-01

    Glasses with composition 10SrO:(30-x)ZnO:60B2O3:xMnO, 0≤x≤0.9 (all compositions in wt%) have been prepared and investigated by X-ray diffraction, EPR, Optical absorption and FT-IR spectroscopic techniques. The XRD pattern of all the glasses confirmed the formation of an amorphous structure. The EPR spectra of all glass samples exhibit resonance signals at g≈2.0 with a sextet of hyperfine lines. The spin concentration (N) and temperature dependence of EPR signals were studied for Mn2+ ions in strontium zinc borate glass samples. The zero-field splitting parameter D has been evaluated from the intensities of the allowed hyperfine lines. The paramagnetic susceptibility (χ) was calculated from EPR data at different temperatures and the Curie temperature (θp) was calculated from the 1/χ verses T graph. The optical absorption spectra exhibit a single broad band near 470 nm and this has been attributed to the spin-allowed 5Eg→5T2g transition of Mn3+ ions in octahedral symmetry. The theoretical optical basicity (Λth) of these glasses have also been evaluated. The FTIR studies show BO3 and BO4 structural units in strontium zinc borate glasses.

  9. The structural, optical and magnetic parameter of manganese doped strontium zinc borate glasses

    Sumalatha, B. [Department of Physics, Acharya Nagarjuna University, Guntur 522510, Andhra Pradesh (India); Omkaram, I. [Department of Physics, Sri Venkateswara University, Tirupati 517502, Andhra Pradesh (India); Rajavardhana Rao, T. [Department of Physics, Acharya Nagarjuna University, Guntur 522510, Andhra Pradesh (India); Linga Raju, Ch., E-mail: drchlraj_phy@yahoo.com [Department of Physics, Acharya Nagarjuna University, Guntur 522510, Andhra Pradesh (India)

    2013-02-15

    Glasses with composition 10SrO:(30−x)ZnO:60B{sub 2}O{sub 3}:xMnO, 0≤x≤0.9 (all compositions in wt%) have been prepared and investigated by X-ray diffraction, EPR, Optical absorption and FT-IR spectroscopic techniques. The XRD pattern of all the glasses confirmed the formation of an amorphous structure. The EPR spectra of all glass samples exhibit resonance signals at g≈2.0 with a sextet of hyperfine lines. The spin concentration (N) and temperature dependence of EPR signals were studied for Mn{sup 2+} ions in strontium zinc borate glass samples. The zero-field splitting parameter D has been evaluated from the intensities of the allowed hyperfine lines. The paramagnetic susceptibility (χ) was calculated from EPR data at different temperatures and the Curie temperature (θ{sub p}) was calculated from the 1/χ verses T graph. The optical absorption spectra exhibit a single broad band near 470 nm and this has been attributed to the spin-allowed {sup 5}E{sub g}→{sup 5}T{sub 2g} transition of Mn{sup 3+} ions in octahedral symmetry. The theoretical optical basicity (Λ{sub th}) of these glasses have also been evaluated. The FTIR studies show BO{sub 3} and BO{sub 4} structural units in strontium zinc borate glasses.

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

    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.

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

    Srinivas, G.; Ramesh, B.; Shareefuddin, Md.; Chary, M. N.; Sayanna, R.

    2016-05-01

    The mixed alkali and alkaline earth oxide borate glass with the composition xK2O - (25-x) Li2O-12.5BaO-12.5MgO-50B2O3 (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(α02-), 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 (α02-), and (Λ) increases with increasing of K2O 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 K2O 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).

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

    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

  13. Synthesis and characterization of borate based and AgGaS2 materials

    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 LiNbO3. 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 RECa4O(BO3)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 (Nd3+, Yb3+), they become efficient laser-host crystals. The single crystals of YCOB were grown by flux technique using boron-tri-oxide as a flux. This technique enables to

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

    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. PMID:25012058

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

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

    2014-01-01

    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.

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

    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. PMID:25631259

  17. Lewis acid-base 1,2-addition reactions: synthesis of pyrylium borates from en-ynoate precursors.

    Wilkins, Lewis C; Hamilton, Hugh B; Kariuki, Benson M; Hashmi, A Stephen K; Hansmann, Max M; Melen, Rebecca L

    2016-03-30

    Treatment of methyl (Z)-2-alken-4-ynoates with the strong Lewis acid tris(pentafluorophenyl) borane, B(C6F5)3, yield substituted zwitterionic pyrylium borate species via an intramolecular 6-endo-dig cyclisation reaction. PMID:26435394

  18. Synthesis and vibrational circular dichroism of enantiopure chiral oxorhenium(V) complexes containing the hydrotris(1-pyrazolyl)borate ligand

    Lassen, Peter Rygaard

    2006-01-01

    The infrared and vibrational circular dichroism (VCD) spectra of six chiral oxorhenium(V) complexes, bearing a hydrotris(1-pyrazolyl)borate (Tp) ligand, have been investigated. These complexes are promising candidates for observation of parity violation (symmetry breaking due to the weak nuclear ...

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

    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.

  20. Effect of borates on thermal degradation and flame retardancy of epoxy resins using polyhedral oligomeric silsesquioxane as a curing agent

    Highlights: ► Flame retarded epoxy resins with borates were prepared using POSS as a curing agent. ► Borates and POSS exhibited a synergistic effect on flame retardancy of epoxy resins. ► Incorporation of borates and POSS significantly reduced the heat release rate. - Abstract: A series of flame-retardant epoxy resins containing boron and silicon were obtained through a crosslinking reaction, using tris (2-hydroxypropyl) borate (THPB) together with octaaminophenyl POSS (OapPOSS) as the curing agents. The limiting oxygen index (LOI) reached 30.5% when the contents of boron and silicon in the cured system were 1.5% and 0.5%, respectively, indicating that THPB and OapPOSS exhibited good flame retardant effect on epoxy resins (EP). Microscale combustion calorimetry (MCC) results indicated that the peak heat release rate (PHRR) and total heat release (THR) of the cured systems were reduced by 69% and 46%, respectively, compared to those of pure EP. Moreover, the thermal degradation process and flame retardant mechanism of the composites were investigated by TGA, real time FTIR and TG-FTIR. The chemical components of the char residues were explored by XPS.

  1. High-pressure synthesis and characterization of the first cerium fluoride borate CeB2O4F

    CeB2O4F is the first cerium fluoride borate, which is exclusively built up of one-dimensional, infinite chains of condensed trigonal-planar [BO3]3− groups. This new cerium fluoride borate was synthesized under high-pressure/high-temperature conditions of 0.9 GPa and 1450 °C in a Walker-type multianvil apparatus. The compound crystallizes in the orthorhombic space group Pbca (No. 61) with eight formula units and the lattice parameters a=821.63(5), b=1257.50(9), c=726.71(6) pm, V=750.84(9) Å3, R1=0.0698, and wR2=0.0682 (all data). The structure exhibits a 9+1 coordinated cerium ion, one three-fold coordinated fluoride ion and a one-dimensional chain of [BO3]3− groups. Furthermore, IR spectroscopy, Electron Micro Probe Analysis and temperature-dependent X-ray powder diffraction measurements were performed. - Graphical abstract: A new rare-earth fluoride borate CeB2O4F could be synthesized under high-pressure/high-temperature conditions of 0.9 °GPa and 1450 °Cin a Walker-type multianvil apparatus. The crystal structure represents a new structure type in the class of rare-earth fluoride borates. The structure exhibits a 9+1 coordinated cerium ion, one three-fold coordinated fluoride ion and a one-dimensional chain of [BO3]3− groups. A closer view on the ac-plane shows an interesting wave-like modulation of the borate chains. Highlights: • CeB2O4F is the first fluoride borate exclusively built up of one-dimensional, infinite chains of condensed trigonal-planar [BO3]3− groups. • CeB2O4F is the first cerium fluoride borate. • High-pressure conditions were necessary to synthesize CeB2O4F

  2. Relationship between Eu3+ reduction and glass polymeric structure in Al2O3-modified borate glasses under air atmosphere

    The reduction of Eu3+ to Eu2+ is realized efficiently in Eu2O3-doped borate glasses prepared under air condition by melting-quenching method. Luminescent spectra show an increasing tendency of Eu2+ emission with increasing Al2O3 concentration in B2O3–Na2O glasses. It is interesting that significant enhancement appeared of Eu2+ luminescence in the Al2O3-rich sample comparing to the samples of Al2O3 less than 6 mol%. FTIR and Raman scattering measurements indicated that some new vibration modes assigned to the low-polymerized structure groups decomposed from the slight Al2O3 dopant samples. These results demonstrated that the polymerization of the glass structure decreased with increasing incorporation of Al2O3 into the borate glasses, linking to the efficiency of Eu3+ self-reduction in air at high temperature. - graphical abstract: A novel europium valence reduction phenomenon occurred in Al2O3 modified borate glasses, FTIR and Raman measurements revealed that high polymeric groups were destroyed to low polymery structures with Al2O3 addition. - Highlights: • The efficient reduction of Eu3+ to Eu2+ is observed in the B2O3–Na2O glasses. • Eu2+ luminescence is significant enhanced in the Al2O3-rich glasses. • The introduction of Al2O3 changed the network structure of the borate glasses. • High polymeric borate groups in the glass matrix may be destroyed to the lower ones

  3. Citrus bergamia Risso Elevates Intracellular Ca2+ in Human Vascular Endothelial Cells due to Release of Ca2+ from Primary Intracellular Stores

    Purum Kang

    2013-01-01

    , which was partially inhibited by a nonselective Ca2+ channel blocker La3+. In Ca2+-free extracellular solutions, BEO increased [Ca2+]i in a concentration-dependent manner, suggesting that BEO mobilizes intracellular Ca2+. BEO-induced [Ca2+]i increase was partially inhibited by a Ca2+-induced Ca2+ release inhibitor dantrolene, a phospholipase C inhibitor U73122, and an inositol 1,4,5-triphosphate (IP3-gated Ca2+ channel blocker, 2-aminoethoxydiphenyl borane (2-APB. BEO also increased [Ca2+]i in the presence of carbonyl cyanide m-chlorophenylhydrazone, an inhibitor of mitochondrial Ca2+ uptake. In addition, store-operated Ca2+ entry (SOC was potentiated by BEO. These results suggest that BEO mobilizes Ca2+ from primary intracellular stores via Ca2+-induced and IP3-mediated Ca2+ release and affect promotion of Ca2+ influx, likely via an SOC mechanism.

  4. Study of neodymium oxide inclusion on the structure of a borate glass

    The structure of borate glass has been well studied by many different authors using a variety of techniques. When other compounds are added to the glass which accommodates them, the structural environment of the inclusions will depend on the type of included elements. Given the large number of applications of borate glasses, a study of the factors that determine the surrounding structure of an included ion in a glass is thus of much relevance. As a first step in such studies, a single ion-type viz. neodymium oxide ( Nd2O3 ) was incorporated in a borate host glass at varying mole percentages of the dopant from 10% to 25%. These glasses were melt-quenched in air from 1450 oC. Transparent bubble-free purple glass beads were obtained and subsequently crushed into fine powders for the X-ray and neutron diffraction measurements. The glass transition temperature was approximately 750 oC. An incident wavelength of 1.54 Å ( CuKα ) was used in the X-ray diffraction studies. Neutron diffraction measurements were made on the High Q diffractometer at Dhruva Reactor, B.A.R.C., Mumbai in the Q range of 0.3 to 15 Å-1 . The diffraction patterns from both techniques showed some trends with concentration in the higher Q regions of S(Q). The real space correlation functions viz. T(r) and number density function N(r) gave clear indications of changes of nearestneighbour coordination number of O around B (at 1.366 Å) as a function of Nd2O3 molar concentration in the glass. Thus in the first peak, the fraction due to tetrahedral BO4 units increases from 28% to 41% with dopant level at the expense of BO3 triangles. From an analysis of the second peak in T(r), super-structural units such as diborate and di-pentaborate units surround the Nd ion at lower dopant levels while the coordination is octahedral at higher levels of dopant. These findings are in keeping with a model that the overall structure of the host glass is affected by the concentration of the dopant ion.

  5. The corrosion behaviour of rare-earth containing magnesium alloys in borate buffer solution

    In this work, the corrosion behaviour of magnesium alloys ZK31, EZ33 and WE54 was studied in sodium borate buffer solution at pH 9.2. The electrochemical processes were studied by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The composition and morphology of the alloys and corrosion products formed were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The experimental findings highlighted the differences in the corrosion mechanisms of the different alloys tested. The results showed that the presence of rare-earth elements (RE) only increases the corrosion resistance when present in solid solution, as is the case of the WE54 alloy. At pH 9.2, an amorphous yttrium oxide/hydroxide thick film was formed, which possesses greater stability when compared to magnesium oxide/hydroxide. The role of RE in the corrosion mechanism was discussed.

  6. Optical properties of down-shifting barium borate glass for CdTe solar cells

    Loos, Sebastian; Steudel, Franziska; Ahrens, Bernd; Schweizer, Stefan

    2015-03-01

    CdTe thin film solar cells have a poor response in the ultraviolet and blue spectral range, mainly due to absorption and thermalization losses in the CdS buffer layer. To overcome this efficiency drop in the short wavelength range trivalent rare-earth doped barium borate glass is investigated for its potential as frequency down-shifting cover glass on top of the cell. The glass is doped with either Tb3+ or Eu3+ up to a level of 2.5 at.% leading to strong absorption in the ultraviolet/blue spectral range. Tb3+ shows intense emission bands in the green spectral range while Eu3+ emits in the orange/red spectral range. Based on rare-earth absorption and luminescence quantum efficiency the possible gain in short-circuit current density is calculated.

  7. Study of the reduction of particle emissions and borate black liquor gasification in bioenergy systems

    Leduc, Sylvain

    2004-11-01

    zone of the boiler. The results from the simulations were validated against measurements. The temperature field was well described and the velocity field was predicted with acceptable accuracy. Chemical reactions were not included in these simulations. Turbulence was modelled using the RNG k-{epsilon} model, which is relatively easy to use. This thesis also performs a study on a new model of black liquor gasification with borate autocausticizing, which has the potential to improve the production performance of pulp mills. The earlier model from Jansson did not have the efficiency expected, and was found unacceptable as a means of replacing the lime cycle. The new process has a real advantage compared to earlier borate autocausticizing processes; it can theoretically be led either on a full scale or as a part of the process to an ordinary causticizing and with moderate borate setting. The booster gasifier is studied. The material and energy balance is formulated for a sulphate- recycling block with this process and is compared with the conventional techniques. The results of the usual black liquor gasification were very close to reality and very promising. Regarding the black liquor gasification with borate, lack of data for the orthoborate, like the Gibbs free energy, did not enable good accuracy of the results. The model is so far a good start in black liquor gasification, but it needs to be improved as soon as some new data are available.

  8. Lasing properties of new Yb-doped borate compounds with varying gadolinium and yttrium concentration

    Manek-Hönninger, Inka; Chavoutier, Marie; Jubera, Véronique; Descamps, Dominique; Veber, Philippe; Velazquez, Matias; Garcia, A.; Canioni, L.

    2011-02-01

    We show spectroscopic and lasing properties of new ytterbium-doped borate compounds with the structure Li6(Gd(1- x)Yx)0.75Yb0.25(BO3)3 with x = 0, 0.25, 0.5, 0.75 and 1, respectively. All compounds show large emission spectra suitable for femtosecond pulse generation. We studied the laser performances in a diode-pumped linear laser cavity on about 1- mm-thick crystal samples having an ytterbium doping concentration of 22 %. The compounds show all cw lasing at wavelengths around 1040 to 1060 nm with a slope efficiency of 32 %. The maximum observed output power was 460 mW at an incident pump power of 1.6 W at 972 nm.

  9. The corrosion behaviour of rare-earth containing magnesium alloys in borate buffer solution

    Pinto, R. [ICEMS, Instituto Superior Tecnico, Technical University of Lisbon (Portugal); Ferreira, M.G.S. [ICEMS, Instituto Superior Tecnico, Technical University of Lisbon (Portugal); CICECO, Universidade de Aveiro (Portugal); Carmezim, M.J. [ICEMS, Instituto Superior Tecnico, Technical University of Lisbon (Portugal); Instituto Politecnico de Setubal, ESTSetubal, DEM (Portugal); Montemor, M.F., E-mail: mfmontemor@ist.utl.p [ICEMS, Instituto Superior Tecnico, Technical University of Lisbon (Portugal)

    2011-01-01

    In this work, the corrosion behaviour of magnesium alloys ZK31, EZ33 and WE54 was studied in sodium borate buffer solution at pH 9.2. The electrochemical processes were studied by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The composition and morphology of the alloys and corrosion products formed were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The experimental findings highlighted the differences in the corrosion mechanisms of the different alloys tested. The results showed that the presence of rare-earth elements (RE) only increases the corrosion resistance when present in solid solution, as is the case of the WE54 alloy. At pH 9.2, an amorphous yttrium oxide/hydroxide thick film was formed, which possesses greater stability when compared to magnesium oxide/hydroxide. The role of RE in the corrosion mechanism was discussed.

  10. Production and characterization of hydrophobic zinc borate by using palm oil

    Nil Baran Acarali; Nurcan Tugrul; Emek Moroydor Derun; Sabriye Piskin

    2013-01-01

    Zinc borate (ZB) was synthesized using zinc oxide, boric acid synthesized from colemanite, and reference ZB as seed. The eff ects of reaction parameters such as reaction time, reactant ratio, and seed ratio on its yield were examined. Then, the eff ects of palm oil with solvents (isopropyl alcohol (IPA), ethanol, and methanol) added to the reaction on its hydrophobicity were explored. Reactions were carried out under determined reaction conditions with magnetically and mechanically stirred systems. The produced ZB was characterized by X-ray diff raction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and measurements of contact angle identified hydrophobicity. The results showed that hydrophobic ZB was successfully produced under determined reaction conditions. The change of process parameters influenced its yield and the usage of palm oil provided hydrophobicity.

  11. Characterization of berkelium(III) dipicolinate and borate compounds in solution and the solid state.

    Silver, Mark A; Cary, Samantha K; Johnson, Jason A; Baumbach, Ryan E; Arico, Alexandra A; Luckey, Morgan; Urban, Matthew; Wang, Jamie C; Polinski, Matthew J; Chemey, Alexander; Liu, Guokui; Chen, Kuan-Wen; Van Cleve, Shelley M; Marsh, Matthew L; Eaton, Teresa M; van de Burgt, Lambertus J; Gray, Ashley L; Hobart, David E; Hanson, Kenneth; Maron, Laurent; Gendron, Frédéric; Autschbach, Jochen; Speldrich, Manfred; Kögerler, Paul; Yang, Ping; Braley, Jenifer; Albrecht-Schmitt, Thomas E

    2016-08-26

    Berkelium is positioned at a crucial location in the actinide series between the inherently stable half-filled 5f(7) configuration of curium and the abrupt transition in chemical behavior created by the onset of a metastable divalent state that starts at californium. However, the mere 320-day half-life of berkelium's only available isotope, (249)Bk, has hindered in-depth studies of the element's coordination chemistry. Herein, we report the synthesis and detailed solid-state and solution-phase characterization of a berkelium coordination complex, Bk(III)tris(dipicolinate), as well as a chemically distinct Bk(III) borate material for comparison. We demonstrate that berkelium's complexation is analogous to that of californium. However, from a range of spectroscopic techniques and quantum mechanical calculations, it is clear that spin-orbit coupling contributes significantly to berkelium's multiconfigurational ground state. PMID:27563098

  12. Corrosion and Passivation of Nickel Rotating Disk Electrode in Borate Buffer Solution

    The electrochemical corrosion and passivation of Ni rotating disk electrod in borate buffer solution was studied with potentiodynamic and electrochemical impedance spectroscopy. The mechanisms of both the active dissolution and passivation of nickel and the hydrogen evolution in reduction reaction were hypothetically established while utilizing the Tafel slope, impedance data, the rotation speed of Ni-RDE and the pH dependence of corrosion potential and current. Based on the EIS data, an equivalent circuit was suggested. In addition, carefully measured were the electrochemical parameters for specific anodic dissolution regions. It can be concluded from the data collected that the Ni(OH)2 oxide film, which is primarily formed by passivation, is converted to NiO by dehydration under the influence of an electrical field

  13. Exploring polymeric lithium tartaric acid borate for thermally resistant polymer electrolyte of lithium batteries

    A novel polymeric lithium tartaric acid borate (PLTB) was synthesized via an one-step reaction in aqueous solution. The polymer electrolyte of PLTB@PVDF-HFP (poly(vinylidene fluoride-co-hexafluoropropene)) was developed by a doctor-blading followed by a soaking process in propylene carbonate (PC). It was manifested that the PC swollen PLTB@PVDF-HFP exhibited excellent electrochemical stability and compatibility with lithium metal electrode, high ionic conductivity and high lithium ion transference number at an operating temperature of 80 °C. The cells using the PC swollen PLTB@PVDF-HFP as electrolyte showed stable charge/discharge profiles, preferable rate capability and satisfactory cycling performance at high temperature. These superior performances of PC swollen PLTB@PVDF-HFP could endow this class of polymer electrolyte a very promising application in lithium batteries operating at relatively high temperature

  14. UV-VIS-NIR spectral optical properties of silver iodide borate glasses

    We present a study of optical properties of a series of silver iodide borate glasses(AgI)x(Ag2O·B2O3)1−xby UV-VIS-NIR spectroscopy. The results show an increased absorbance in the whole analysed spectral range when the AgI concentration is augmented. In particular, the enhanced intensity of the wavelength band at 400–500 nm with silver iodine content suggests that this band arises from plasmon-related absorption, describing the formation of silver nanoparticles. With respect to this study, our results could motivate novel target designs consisting of ternary silver boron based bulk glasses for generating resonant absorption of laser light by plasma.

  15. Complex Heat Capacity of Lithium Borate Glasses Studied by Modulated DSC

    Complex heat capacity, Cp* = Cp' - iCp'', of lithium borate glasses Li2O·(1-x)B2O3 (x = 0.00 - 0.33) has been investigated by Modulated DSC (MDSC). We have successfully observed the frequency dependent Cp* by MDSC in the frequency range 0.01 to 0.1 Hz, and the average relaxation time of glass transition has been determined as a function of temperature. Moreover, the composition dependence of the thermal properties has been investigated. The calorimetric glass transition temperatures become higher with the increase of concentration of Li2O and show the board maximum around x = 0.26-0.28. The width of glass transition region becomes narrower as Li2O increases. These results relate to the change of the fragility of the system. It has been proven that the complex heat capacity spectroscopy by MDSC is a powerful tool to investigate the glass transition phenomena

  16. Complex Heat Capacity of Lithium Borate Glasses Studied by Modulated DSC

    Matsuda, Yu; Matsui, Chihiro; Ike, Yuji; Kodama, Masao; Kojima, Seiji

    2006-05-01

    Complex heat capacity, Cp* = Cp' - iCp″, of lithium borate glasses Li2Oṡ(1-x)B2O3 (x = 0.00 - 0.33) has been investigated by Modulated DSC (MDSC). We have successfully observed the frequency dependent Cp* by MDSC in the frequency range 0.01 to 0.1 Hz, and the average relaxation time of glass transition has been determined as a function of temperature. Moreover, the composition dependence of the thermal properties has been investigated. The calorimetric glass transition temperatures become higher with the increase of concentration of Li2O and show the board maximum around x = 0.26-0.28. The width of glass transition region becomes narrower as Li2O increases. These results relate to the change of the fragility of the system. It has been proven that the complex heat capacity spectroscopy by MDSC is a powerful tool to investigate the glass transition phenomena.

  17. Generation of ultraviolet radiation with wide angular tolerance in cesium lithium borate crystal

    Gopal C Bhar; Pathik Kumbhakar; Anil K Chaudhary

    2000-09-01

    Tangential phase-matching has been realised in cesium lithium borate (CLBO) crystal for the first time for the generation of fourth harmonic (266 nm) of Nd:YAG and third harmonic (226.7 nm) of a dye laser radiation by second harmonic generation and sum-frequency mixing with the angular tolerance as large as 22 mrad and 21 mrad respectively, over one of the interacting beams. An energy conversion efficiency of 15% for fourth harmonic generation is obtained with a 5.5 mm thick crystal and with the average pump powers only 170 and 70 mW. A set of Sellmeier dispersion equations for the CLBO crystal have also been formulated.

  18. Nonlinear optical properties of silver nanoparticles prepared in Ag doped borate glasses

    Adamiv, V.T. [Institute of Physical Optics, Dragomanov str. 23, Lviv 79005 (Ukraine); Bolesta, I.M. [Ivan Franko National University, Dragomanov str. 50, Lviv 79005 (Ukraine); Burak, Ya.V., E-mail: burak@ifo.lviv.ua [Institute of Physical Optics, Dragomanov str. 23, Lviv 79005 (Ukraine); Gamernyk, R.V.; Karbovnyk, I.D.; Kolych, I.I.; Kovalchuk, M.G.; Kushnir, O.O.; Periv, M.V. [Ivan Franko National University, Dragomanov str. 50, Lviv 79005 (Ukraine); Teslyuk, I.M. [Institute of Physical Optics, Dragomanov str. 23, Lviv 79005 (Ukraine)

    2014-09-15

    Nonlinear properties of Li{sub 2}B{sub 4}O{sub 7}:Ag borate glasses with “Li{sub 2}B{sub 4}O{sub 7}:Ag nanoparticles” interface region formed by thermal treatment in hydrogen atmosphere and in vacuum are investigated. From the results of plasmon absorption and normalized transmission measurements in Z-scan regime it was ascertained that “Li{sub 2}B{sub 4}O{sub 7}:AgNPs” interface region changes the character of nonlinear refraction of Li{sub 2}B{sub 4}O{sub 7}:Ag glass from negative to positive, and, due to plasmon resonance, increases significantly its nonlinear properties. In particular, the observed growth of nonlinear refractive index n{sub 2} is more than four orders of magnitude.

  19. Nonlinear optical properties of silver nanoparticles prepared in Ag doped borate glasses

    Nonlinear properties of Li2B4O7:Ag borate glasses with “Li2B4O7:Ag nanoparticles” interface region formed by thermal treatment in hydrogen atmosphere and in vacuum are investigated. From the results of plasmon absorption and normalized transmission measurements in Z-scan regime it was ascertained that “Li2B4O7:AgNPs” interface region changes the character of nonlinear refraction of Li2B4O7:Ag glass from negative to positive, and, due to plasmon resonance, increases significantly its nonlinear properties. In particular, the observed growth of nonlinear refractive index n2 is more than four orders of magnitude

  20. Highly active cobalt phosphate and borate based oxygen evolving catalysts operating in neutral and natural waters

    Esswein, AJ; Surendranath, Y; Reece, SY; Nocera, DG

    2011-02-01

    A high surface area electrode is functionalized with cobalt-based oxygen evolving catalysts (Co-OEC = electrodeposited from pH 7 phosphate, Pi, pH 8.5 methylphosphonate, MePi, and pH 9.2 borate electrolyte, Bi). Co-OEC prepared from MePi and operated in Pi and Bi achieves a current density of 100 mA cm(-2) for water oxidation at 442 and 363 mV overpotential, respectively. The catalyst retains activity in near-neutral pH buffered electrolyte in natural waters such as those from the Charles River (Cambridge, MA) and seawater (Woods Hole, MA). The efficacy and ease of operation of anodes functionalized with Co-OEC at appreciable current density together with its ability to operate in near neutral pH buffered natural water sources bodes well for the translation of this catalyst to a viable renewable energy storage technology.

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

    Zhou, Binbin; Bache, Morten

    2015-09-15

    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 in the normal dispersion regime of BBO through a negative cascaded quadratic nonlinearity. Using pump wavelengths from 1.24 to 1.4 μm, dispersive waves are found from 1.9 to 2.2 μm, agreeing well with calculated resonant phase-matching wavelengths due to degenerate four-wave mixing to the soliton. We also observe resonant radiation from nondegenerate four-wave mixing between the soliton and a probe wave, which was formed by leaking part of the pump spectrum into the anomalous dispersion regime. We confirm the experimental results through simulations. PMID:26371910

  2. The passivity of Type 316L stainless steel in borate buffer solution

    Nicic, Igor; Macdonald, Digby D.

    2008-09-01

    The passivity of Type 316 SS in borate buffer solution (pH 8.35), in the steady-state, has been explored using a variety of electrochemical techniques, including potentiostatic polarization, Mott Schottky analysis, and electrochemical impedance spectroscopy. The study shows that the passive film is an n-type semiconductor with a donor density that is essentially independent of voltage across the passive state. The passive current density is also found to be voltage-independent, but the thickness of the barrier layer depends linearly on the applied voltage. These observations are consistent with the predictions of the Point Defect Model, noting that the point defects within the barrier layer of the passive film are metal interstitials or oxygen vacancies, or both. No evidence for p-type behavior was obtained, indicating that cation vacancies do not have a significant population density in the film compared with the two donors (cation interstitials and oxygen vacancies).

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

    Harde, G. B.; Muley, G. G.

    2016-05-01

    Borate glasses of the system xNd2O3-(1-x) La2O3-SrCO3-10H3BO3 (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 4I9/2 → 4G5/2 + 2G7/2 has found more prominent than the other transitions. Optical band gap energies of glasses have been determined and found less for Nd doped glass.

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

    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.

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

    Priyada, P.; Ashwini, U.; Sarkar, P. K.

    2016-05-01

    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 10-8 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.

  6. The passivity of Type 316L stainless steel in borate buffer solution

    The passivity of Type 316 SS in borate buffer solution (pH 8.35), in the steady-state, has been explored using a variety of electrochemical techniques, including potentiostatic polarization, Mott Schottky analysis, and electrochemical impedance spectroscopy. The study shows that the passive film is an n-type semiconductor with a donor density that is essentially independent of voltage across the passive state. The passive current density is also found to be voltage-independent, but the thickness of the barrier layer depends linearly on the applied voltage. These observations are consistent with the predictions of the Point Defect Model, noting that the point defects within the barrier layer of the passive film are metal interstitials or oxygen vacancies, or both. No evidence for p-type behavior was obtained, indicating that cation vacancies do not have a significant population density in the film compared with the two donors (cation interstitials and oxygen vacancies)

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

    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. PMID:25089381

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

    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.

  9. Nuclear quadrupole interaction and nonlinear optical property of some borate crystals^*

    Choh, S. H.; Kim, I. G.; Shin, H. W.; Park, I.-W.

    2003-03-01

    Borate crystals, like Li_2B_4O_7, LiB_3O_5, and BaB_2O_4, consist of 4-coordinated and/or 3-coordinated boron-oxygen bonds. As reported [1], the principal Z-axis of the electric field gradient (EFG) around the boron in 3-coordinated bonds is perpendicular to the plane containing the boron-oxygen bonds. We calculated the principal Z-direction of the EFG-tensor by employing the simple point charge model for the arbitrary planar triangle configurations, and the results are consistent with experimental ones. Moreover, a strong correlation between the nonlinear optical coefficient and the nuclear quadrupole interactions, such as the quadrupole coupling constant and the asymmetry parameter, was empirically found for these compounds. Details will be presented. * Supported by the National Research Laboratory Program(MOST). [1] I. G. Kim and S. H. Choh, J. Phys.: Condens. Matter, b11, 8283 (1999).

  10. Luminescent properties of LiB3O5 lithium three borate crystals

    The results of investigation into luminescent properties of LiB3O5 (LBO) lithium tri borate crystals are presented. As a result of the conducted investigation into excitation and photoluminescence spectra of nominally pure oriented LBO crystals within wide spectral (1.2 eV - 10.5 eV) and temperature (8 K - 500 K) ranges it is revealed that LBO wide-band luminescence within 3.5 - 4.5 eV range is determined to be excited efficiently by over 7.5 eV energy photons in recombination processes and under corpuscular or X-ray irradiation. On the basis of the experimental data the conclusion is made about eigennature of LBO luminescence and its dependence on emitting decay of relaxed electron excitations

  11. Electrochemical passivation behaviour of nanocrystalline Fe80Si20 coating in borate buffer solution

    G Gupta; A P Moon; K Mondal

    2013-02-01

    Passivation behaviour of nanocrystalline coating (Fe80Si20) obtained by in situ mechanical alloying route is studied and compared with that of the commercial pure iron and cast Fe80Si20 in sodium borate buffer solution at two different pH values (7.7 and 8.4). The coating reveals single passivation at a pH of 7.7 and double stage passivity at a pH of 8.4. The first passive layer is due to the dissolution mechanism and second passivity is related to stable passivation. The cast sample shows single stage passivity in the solution of pH 8.4. The difference in the passivation behaviour for the cast alloy (Fe80Si20) and the coating is related to the presence of highly iron-enriched localized regions, formed during the processing stage of coating.

  12. Structural, dielectric and AC conductivity properties of Co2+ doped mixed alkali zinc borate glasses

    Madhu, B. J.; Banu, Syed Asma; Harshitha, G. A.; Shilpa, T. M.; Shruthi, B.

    2013-02-01

    The Co2+ doped 19.9ZnO+5Li2CO3+25Na2CO3+50B2O3 (ZLNB) mixed alkali zinc borate glasses have been prepared by a conventional melt quenching method. The structural (XRD & FT-IR), dielectric and a.c. conductivity (σac) properties have been investigated. Amorphous nature of these glasses has been confirmed from their XRD pattern. The dielectric properties and electrical conductivity (σac) of these glasses have been studied from 100Hz to 5MHz at the room temperature. Based on the observed trends in the a.c. conductivities, the present glass samples are found to exhibit a non-Debye behavior.

  13. Method of volume-reducing for radioactive sodium borate liquid wastes and its device

    Purpose: To easily obtain glass solidification products with efficient volume-reducing effect and high water-proofness from liquid wastes discharged from PWR type reactors. Method: Sodium borate liquid wastes pre-condensated and adjusted to pH 8 - 9 are incorporated with ZnO (or inorganic ZnO compound being capable of converting into ZnO after melting) or a mixture of ZnO with Al2O3 or CaO, irradiated by microwaves into glass solidification products (B2O3-Na2O-ZnO). The molar ratio of Na2O to B2O3 contained in liquid wastes is adjusted to between 0.1 - 0.6. The ZnO content is set to 10 - 40 mol%. (Ikeda, J.)

  14. Wavelength interdependence assessment of all-optical switching in zinc borate glasses

    Abdel-Baki, Manal; Abdel-Wahab, Fathy; El-Diasty, Fouad

    2012-08-01

    Lithium tungsten borate photonic glass is prepared by the conventional melt-quench technique. Due to semiconductor-like behavior of zinc oxide, the glass is doped by ZnO to adapt its optical nonlinearity. Fresnel-based spectrophotometric measurements and Lorentz dispersion theory are applied to study (in a very wide range of photon energy from 0.5 to 6.2 eV) the dispersion of second-order refractive index, two-photon absorption coefficient, and third-order optical susceptibility of the glass. The figure of merit (FOM) needed for optical switching applications is estimated. We reveal the importance of determining the dispersion of the optical nonlinear parameters to find out the appropriate operating wavelength for optimum FOM of the glass.

  15. Production and characterization of hydrophobic zinc borate by using palm oil

    Acarali, Nil Baran; Tugrul, Nurcan; Derun, Emek Moroydor; Piskin, Sabriye

    2013-11-01

    Zinc borate (ZB) was synthesized using zinc oxide, boric acid synthesized from colemanite, and reference ZB as seed. The effects of reaction parameters such as reaction time, reactant ratio, and seed ratio on its yield were examined. Then, the effects of palm oil with solvents (isopropyl alcohol (IPA), ethanol, and methanol) added to the reaction on its hydrophobicity were explored. Reactions were carried out under determined reaction conditions with magnetically and mechanically stirred systems. The produced ZB was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and measurements of contact angle identified hydrophobicity. The results showed that hydrophobic ZB was successfully produced under determined reaction conditions. The change of process parameters influenced its yield and the usage of palm oil provided hydrophobicity.

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

    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.

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

    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. - Highlights: • Calcium silicate borate Ca11Si4B2O22 ceramics were developed as a new biomaterial. • Ca11Si4B2O22 shows a superior in vitro bioactivity by inducing bone-like apatite. • Ca11Si4B2O22 has good mechanical properties as potential candidate biomaterials. • The structure with SiO4 and BO3 groups is favorable for hydroxyapatite formation

  18. Kinetics of fluorescence properties of Eu3+ion in strontium-aluminium-bismuth-borate glasses

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

    2014-01-01

    Eu3+doped strontium-aluminium-bismuth-borate glasses with the chemical composition (50–x)B2O3+20Bi2O3+7AlF3+8SrO+15SrF2+xEu2O3 (where x=0.1 mol.%, 0.5 mol.%, 1.0 mol.%and 1.5 mol.%) were prepared by the conventional melt quenching technique. Structural properties of the prepared glasses were analysed through X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and Raman spectral techniques. Thermal stability of glass was analysed by differential thermal analysis (DTA) curve. Photoluminescence characteristics were studied using excitation, emission spectra and decay curves of Eu3+doped strontium-aluminium-bismuth-borate glasses. The Judd-Ofelt (J-O) intensity parameters,Ωλ(λ=2, 4 and 6) were obtained using emission spectra and was used to identify the nature of Eu3+ions with their surrounding ligands. Using J-O parameters the tran-sition probabilities (A), stimulated emission cross-sections σEp , branching ratios (βR) and radiative lifetimes (τmeas and τcal) were evaluated for the 5D0→7FJ (J=0, 1, 2, 3 and 4) transition of Eu3+ions in the present glasses. The decay profiles were found to be non exponential for all the concentrations and the measured lifetimes (τmeas) were obtained from the decay profiles. The higher values of A,σEp ,βR and quantum efficiency (η) for 5D0→7F2 emission transition at 617 nm confirmed the present glass was as active medium for red laser emission applications.

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

    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 Ag2O–0.13 B2O3 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)[0.67Ag2O–0.33B2O3], 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 0–106 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

  20. Photoluminescence, and scintillation/thermoluminescence yields of several Ce3+ and Eu2+ activated borates

    Powder samples of the borates YBO3 : Ce3+, GdBO3 : Ce3+, Li6Y(BO3)3 : Ce3+, LaB3O6 : Ce3+, GdB3O6 : Ce3+, LaMgB5O10 : Ce3+, YMgB5O10 : Ce3+, CaLaB7O13 : Ce3+, CaLaB7O13 : Eu2+, Ca4YO(BO3)3 : Ce3+ and CaYOBO3 : Eu2+ were studied. The photoluminescence properties of Ce3+ in these compounds are discussed and some of them are reported for the first time. The scintillation light yield of the orthoborates YBO3 : Ce3+, GdBO3 : Ce3+, ScBO3 : Ce3+ and YAl3B4O12 : Ce3+ is of the order of 10,000 pho/MeV. The light yield due to Ce3+ in the other borates is an order of magnitude lower. In LaB3O6 : Ce3+ and LaMgB5O10 : Ce3+ a broad emission band, attributed to self-trapped exciton (STE) emission, is observed under X-ray excitation. The STE light yield of LaB3O6 : Ce3+ (0.05%) is 8000 pho/MeV and it is quenched at higher Ce concentrations. Thermoluminescence measurements show that none of these materials has a potential to be utilized as a thermal neutron storage phosphor

  1. Advanced Detection Technology of Trace-level Borate for SG Leakage Monitoring

    Many studies have been reported for monitoring technology of steam generator, however, all of these methods have their own limitations. The leakage monitoring technology of steam generator of PWR has also got a limit due to the adoption of specific radionuclides (N-16, Ar-41, H-3, Xe, etc.) generated by nuclear fission, which are available only when reactor output is 20% or more. Most of domestic NPPs apply the N-16 technique for monitoring tube leakage but it has some problem that it is difficult to calculate the leakage rate because neutron flux are not completely formed during low power operation. For example, tube leakage of steam generator occurred in the Uljin nuclear power plant in 2002 during coast down operation for periodic plant maintenance. This plant could not prevent a rupture accident in advance because N-16 method is not possible the leak monitoring less than 20% reactor power. The development of excellent alternative monitoring technology that can monitor the real-time leakage is required under a variety of operating conditions like start-up and abnormal conditions of NPPs. This study was performed to lay a foundation in monitoring the leakage of steam generator coping with the lower output and low power operational condition using trace level of boron which is non-radioactive nuclide to inject control neutron injection. In this study, non-radioactive nuclide boron ion, which existed in the secondary system water, as leakage monitoring indicator was investigated for the separation of complex cation and anion phase. Borate was detected by using borate concentrator column coupled with the ion-exclusion column analytical column, revealing the problem of overlapped peak between fluoride and boron ions. Meanwhile, ion-exchange column could confirm the possibility as a leakage monitoring indicator of steam generator, despite the peak of glycolic acid salts was slightly overlapped. It will be needed for further research regarding the selectivity of the

  2. Spectroscopic properties and luminescence behavior of Nd3+ doped zinc alumino bismuth borate glasses

    Mahamuda, Sk.; Swapna, K.; Srinivasa Rao, A.; Jayasimhadri, M.; Sasikala, T.; Pavani, K.; Rama Moorthy, L.

    2013-09-01

    Zinc Alumino Bismuth Borate (ZnAlBiB) glasses doped with different concentrations of neodymium are prepared by using the melt quenching technique to study their physical, absorption and luminescence properties to understand the lasing potentialities of these glasses. From the absorption spectra various spectroscopic parameters and Judd-Ofelt (JO) parameters are evaluated. These JO parameters are used to calculate the transition probability (A), radiative lifetime (τR), and branching ratios (βR) for most of the fluorescent levels of Nd3+. The emission spectra recorded for these glasses gives three prominent transitions 4F3/2→4I9/2, 4F3/2→4I11/2 and 4F3/2→4I13/2 for which effective band widths (ΔλP) and stimulated emission cross-sections (σse) are evaluated. Branching ratios and stimulated emission cross-sections measured for all these glasses show that the 4F3/2→4I11/2 transition under investigation has the potential for laser applications. The intensity of Nd3+ emission spectra increases with increasing concentrations of Nd3+ up to 1 mol% and beyond 1 mol% the concentration quenching is observed. The high stimulated emission cross-section and branching ratios from the present glasses suggests their potential for infrared lasers. From the absorption and emission spectral studies it was found that, 1 mol% of Nd3+ ion concentration is optimum for Zinc Alumino Bismuth Borate glasses to generate a strong laser emission at 1060 nm.

  3. Conductivity and modulus formulation in lithium modified bismuth zinc borate glasses

    Dahiya, Sajjan; Punia, R.; Murugavel, S.; Maan, A. S.

    2016-05-01

    The conductivity and modulus formulation in lithium modified bismuth zinc borate glasses with compositions xLi2O-(50-x) Bi2O3-10ZnO-40B2O3 has been studied in the frequency range 0.1 Hz-1.5 × 105 Hz in the temperature range 573 K-693 K. The temperature and frequency dependent conductivity is found to obey Jonscher's universal power law for all the studied compositions, the dc conductivity (σdc), crossover frequency (ωH), and frequency exponent (s) have been estimated from the fitting of the experimental data of ac conductivity with Jonscher's universal power law. Enthalpy to dissociate the cation from its original site next to a charge compensating centre (Hf) and enthalpy of migration (Hm) have been estimated. It has been observed that number of charge carriers and ac conductivity in the lithium modified bismuth zinc borate glasses increases with increase in Li2O content. Further, the conduction mechanism in the glass sample with x = 0 may be due to overlapping large polaron tunneling, whereas, conduction mechanism in other studied glass samples more or less follows diffusion controlled relaxation model. The ac conductivity is scaled using σdc and ωH as the scaling parameter and is found that these are suitable scaling parameter for conductivity scaling. Non-Debye type relaxation is found prevalent in the studied glass system. Scaling of ac conductivity as well as electric modulus confirms the presence of different type of conduction mechanism in the glass samples with x = 0 and 5 from other studied samples. The activation energy of relaxation (ER) and dc conductivity (Edc) are almost equal, suggesting that polarons/ions have to overcome same barrier while relaxing and conducting.

  4. High-average-power (15-W) 255-nm source based on second-harmonic generation of a copper laser master oscillator power amplifier system in cesium lithium borate

    Brown, Daniel J. W.; Withford, Michael J.

    2001-12-01

    We have generated 15 W of UV (255-nm) radiation with an optical conversion efficiency of 28% by frequency doubling the 510.6-nm output of a high-beam-quality, high-power copper laser system in cesium borate lithium (CLBO). We found that the superior performance of CLBO relative to β-barium borate is attributable largely to the small UV absorption and wide temperature acceptance bandwidth of CLBO, which reduces thermal dephasing during high-power UV generation.

  5. High-Pressure Synthesis and Characterization of the Actinide Borate Phosphate U2[BO4][PO4].

    Hinteregger, Ernst; Wurst, Klaus; Perfler, Lukas; Kraus, Florian; Huppertz, Hubert

    2013-10-14

    A new actinide borate phosphate, U2[BO4][PO4], was synthesized in a Walker-type multianvil apparatus at 12.5 GPa and 1000 °C. The crystal structure was determined from single-crystal X-ray diffraction data collected at room temperature. U2[BO4][PO4] crystallizes in the monoclinic space group P21/c with four formula units per unit cell and the lattice parameters a = 854.6(2), b = 775.3(2), c = 816.3(2) pm, and β = 102.52(3)°. The structure consists of double layers of linked uranium-oxygen polyhedra parallel to [100]. The borate tetrahedra are located between the uranium-oxygen layers inside the double layer. The phosphate groups link the double layers. PMID:24611029

  6. Characterisation and determination of the neutron transmission properties of sodium-calcium and sodium borates from different regions in Turkey

    In this study, ulexite, probertite found within sodium-calcium borates and borax, and tincalconite found within sodium borates retrieved from different regions in Turkey are evaluated for their neutron irradiation performances. Characterisations were performed using XRD, FT-IR, Raman spectroscopy. B2O3 contents were determined experimentally, structural water contents and surface morphologies were determined using DTA/TG and SEM. Neutron transmission values and total macroscopic cross-sections were determined using 239Pu-Be source moderated in a howitzer. Neutron transmission values from lowest to highest were found to be as follows: secondary ulexite (Kirka), tincalconite (Kirka), ulexite (Kestelek), ulexite (Kirka), borax (Kirka), probertite (Kestelek) and ulexite (Bigadic). (author)

  7. Periodic trends and easy estimation of relative stabilities in 11-vertex nido-p-block-heteroboranes and -borates

    Kiani, Farooq A.; Hofmann, Matthias

    2005-01-01

    Density functional theory computations were carried out for 11-vertex nido-p-block-hetero(carba)boranes and -borates containing silicon, germanium, tin, arsenic, antimony, sulfur, selenium and tellurium heteroatoms. A set of quantitative values called “estimated energy penalties” was derived by comparing the energies of two reference structures that differ with respect to one structural feature only. These energy penalties behave additively, i.e., they allow us to reproduce the DFT-computed r...

  8. Borate cross-linking chitosan/graphene oxide films: Toward the simultaneous enhancement of gases barrier and mechanical properties

    Yan, Ning; Capezzuto, Filomena; Buonocore, Giovanna G.; Tescione, Fabiana; Lavorgna, Marino; Xia, Hesheng; Ambrosio, Luigi

    2015-12-01

    Borate adducts, originated from hydrolysis of sodium tetraborate decahydrate (borax), have been used to crosslink chitosan (CS) and graphene oxide (GO) nanosheets for the production of innovative composite sustainable materials. CS/GO film consisting of 10wt% borax and 1wt% GO exhibits a significant improvement of both toughness and oxygen barrier properties in comparison to pristine chitosan. In particular the tensile strength increases by about 100% and 150% after thermal annealing of samples at 90°C for 50min whereas the oxygen permeability reduces of about 90% compared to pristine chitosan. The enhancement of both mechanical and barrier properties is ascribed to the formation of a resistant network due to the chemical crosslinking, including borate orthoester bonds and hydroxyl moieties complexes, formed among borate ions, chitosan, and GO nanoplatelets. The crosslinked graphene-based chitosan material with its enhanced mechanical and barrier properties may significantly broad the range of applications of chitosan based-materials which presently are very limited and addressed only to packaging.

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

    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.

  10. Boron isotope composition of geothermal fluids and borate minerals from salar deposits (central Andes/NW Argentina)

    Kasemann, Simone A.; Meixner, Anette; Erzinger, Jörg; Viramonte, José G.; Alonso, Ricardo N.; Franz, Gerhard

    2004-06-01

    We have measured the boron concentration and isotope composition of regionally expansive borate deposits and geothermal fluids from the Cenozoic geothermal system of the Argentine Puna Plateau in the central Andes. The borate minerals borax, colemanite, hydroboracite, inderite, inyoite, kernite, teruggite, tincalconite, and ulexite span a wide range of δ11B values from -29.5 to -0.3‰, whereas fluids cover a range from -18.3 to 0.7‰. The data from recent coexisting borate minerals and fluids allow for the calculation of the isotope composition of the ancient mineralizing fluids and thus for the constraint of the isotope composition of the source rocks sampled by the fluids. The boron isotope composition of ancient mineralizing fluids appears uniform throughout the section of precipitates at a given locality and similar to values obtained from recent thermal fluids. These findings support models that suggest uniform and stable climatic, magmatic, and tectonic conditions during the past 8 million years in this part of the central Andes. Boron in fluids is derived from different sources, depending on the drainage system and local country rocks. One significant boron source is the Paleozoic basement, which has a whole-rock isotopic composition of δ11B=-8.9±2.2‰ (1 SD); another important boron contribution comes from Neogene-Pleistocene ignimbrites ( δ11B=-3.8±2.8‰, 1 SD). Cenozoic andesites and Mesozoic limestones ( δ11B≤+8‰) provide a potential third boron source.

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

    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.

  12. Scale-up synthesis of zinc borate from the reaction of zinc oxide and boric acid in aqueous medium

    Kılınç, Mert; Çakal, Gaye Ö.; Yeşil, Sertan; Bayram, Göknur; Eroğlu, İnci; Özkar, Saim

    2010-11-01

    Synthesis of zinc borate was conducted in a laboratory and a pilot scale batch reactor to see the influence of process variables on the reaction parameters and the final product, 2ZnO·3B 2O 3·3.5H 2O. Effects of stirring speed, presence of baffles, amount of seed, particle size and purity of zinc oxide, and mole ratio of H 3BO 3:ZnO on the zinc borate formation reaction were examined at a constant temperature of 85 °C in a laboratory (4 L) and a pilot scale (85 L) reactor. Products obtained from the reaction in both reactors were characterized by chemical analysis, X-ray diffraction, particle size distribution analysis, thermal gravimetric analysis and scanning electron microscopy. The kinetic data for the zinc borate production reaction was fit by using the logistic model. The results revealed that the specific reaction rate, a model parameter, decreases with increase in particle size of zinc oxide and the presence of baffles, but increases with increase in stirring speed and purity of zinc oxide; however, it is unaffected with the changes in the amount of seed and reactants ratio. The reaction completion time is unaffected by scaling-up.

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

    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. PMID:26117744

  14. 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

    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)

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

    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

  16. Synthesis and crystal structure of a novel ludwigite borate: Mg2InBO5

    Graphical abstract: The new compound Mg2InBO5 belongs to the ludwigite family, in which their crystal structures are similar. The Mg/InO6 octahedra connect each other by sharing edges to form two flat walls along the c-axis in the sequence M3–M2–M3 and M1–M4–M1. The unit cell in Mg2InBO5 along the c axis. The cation sites: M1, M2, M3 and M4 are represented by 1, 2, 3 and 4, respectively. Highlights: •A novel ludwigite borate Mg2InBO5 has been synthesized by solid-state reaction for the first time. •Crystal structure of Mg2InBO5 was ab initio determined using powder X-ray diffraction method. •The [BO3]3− group was confirmed by infrared absorption spectrum of Mg2InBO5. •The structure characteristics of the ludwigite family were reviewed. -- Abstract: A novel ludwigite borate Mg2InBO5 has been synthesized by solid-state reaction. Its crystal structure was solved by program Jana2006 from powder X-ray diffraction data, and then refined using Rietveld method. It crystallizes in the Pbam space group (No. 55) with a = 12.54806(8) Å, b = 9.46943(6) Å, c = 3.13855(2) Å, V = 372.932(4) Å3, and Z = 4. The disorder of Mg and In atoms exists in Mg2InBO5. The In atoms prefer to occupy the M1 and M2 site, while Mg atoms tend to occupy the M3 and M4 sites, which is in agreement well with the cation distributions in the ludwigite family. The crystal structure of Mg2InBO5 is built from Mg/InO6 octahedra and trigonal BO3 groups stacking layer upon layer along the c-axis. The Mg/InO6 octahedra connect each other by sharing edges to form two flat walls along the c-axis in the sequence M3–M2–M3 and M1–M4–M1. The trigonal BO3 group in Mg2InBO5 was confirmed by infrared absorption spectrum, and UV–Vis diffuse reflectance spectrum of Mg2InBO5 has been measured. The structure characteristics of the ludwigite family were reviewed, with a possible rule proposed

  17. Electronic polarizability and interaction parameter of gadolinium tungsten borate glasses with high WO3 content

    Glasses with the compositions of 25Gd2O3–xWO3–(75−x)B2O3 with x=25–65 were prepared by using a conventional melt quenching method, and their electronic polarizabilities, optical basicities Λ(no), and interaction parameters A(no) were estimated from density and refractive index measurements in order to clarify the feature of electronic polarizability and bonding states in the glasses with high WO3 contents. The optical basicity of the glasses increases monotonously with the substitution of WO3 for B2O3, and contrary the interaction parameter decreases monotonously with increasing WO3 content. A good linear correlation was observed between Λ(no) and A(no) and between the glass transition temperature and A(no). It was proposed that Gd2O3 oxide belongs to the category of basic oxide with a value of A(no)=0.044 Å−3 as similar to WO3. The relationship between the glass formation and electronic polarizability in the glasses was discussed, and it was proposed that the glasses with high WO3 and Gd2O3 contents would be a floppy network system consisting of mainly basic oxides. - Graphical abstract: This figure shows the correlation between the optical basicity and interaction parameter in borate-based glasses. The data obtained in the present study for Gd2O3–WO3–B2O3 glasses are locating in the correlation line for other borate glasses. These results shown in Fig. 8 clearly demonstrate that Gd2O3–WO3–B2O3 glasses having a wide range of optical basicity and interaction parameter are regarded as glasses consisting of acidic and basic oxides. - Highlights: • Gd2O3–WO3–B2O3 glasses with high WO3 contents were prepared. • Electronic polarizability and interaction parameter were estimated. • Optical basicity increases monotonously with increasing WO3 content. • Interaction parameter decreases monotonously with increasing WO3 content. • Glasses with high WO3contents is regarded as a floppy network system

  18. Structural and luminescence properties of Dy{sup 3+} ion in strontium lithium bismuth borate glasses

    Rajesh, D. [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India); Ratnakaram, Y.C., E-mail: ratnakaram_yc@yahoo.co.in [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India); Seshadri, M.; Balakrishna, A. [Department of Physics, Sri Venkateswara University, Tirupati 517502 (India); Satya Krishna, T. [Department of Physics, University of Hyderabad, Hyderabad (India)

    2012-03-15

    Different concentrations of dysprosium doped strontium lithium bismuth borate (SLBiB) glasses were synthesized by the conventional melt quenching method and characterized through X-ray diffraction, Raman, absorption and visible luminescence spectroscopies. These Dy{sup 3+} doped glasses are studied for their utility for white light emitting diodes. X-ray diffraction studies revealed amorphous nature of the studied glass matrices. Coexistence of trigonal BO{sub 3} and tetrahedral BO{sub 4} units was evidenced by Raman spectroscopy. From the absorption spectra, Judd-Ofelt (J-O) intensity parameters, {Omega}{sub {lambda}} ({lambda}=2, 4 and 6), have been calculated. The hypersensitivity of the transition, {sup 6}H{sub 15/2}{yields}{sup 6}F{sub 11/2} of Dy{sup 3+} has been discussed based on the magnitude of {Omega}{sub 2} parameter. Using J-O intensity parameters, several radiative properties such as spontaneous transition probabilities (A{sub R}), radiative branching ratios ({beta}{sub R}) and radiative lifetimes ({tau}{sub R}) have been determined. From the emission spectra, a strong blue emission that corresponds to the transition, {sup 4}F{sub 9/2}{yields}{sup 6}H{sub 15/2}, was observed and it also shows combination of blue, yellow and red emission bands for these glasses. In addition to that, white light emission region have been observed from these studies. - Highlights: Black-Right-Pointing-Pointer Strontium lithium bismuth borate glasses (SLBiB) doped with different concentrations of dysprosium ion were synthesized by the melt quenching method. Black-Right-Pointing-Pointer Judd-Ofelt parameters {Omega}{sub {lambda}} ({lambda}=2, 4 and 6) for studied glasses are reported and these are compared with other glass matrices. Black-Right-Pointing-Pointer The intensity of emission spectra increases up to 0.5 mol% of Dy{sup 3+} ions' concentration and then decreases. Black-Right-Pointing-Pointer Among the three emission transitions, {sup 4}F{sub 9/2}{yields

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

    Lithium tungsten borate glass (0.56-x)B2O3-0.4Li2O-xZnO-0.04WO3 (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 B2O3 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 B2O3, 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.

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

    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

  1. Oxide film formation on a microcrystalline Al alloy at various temperatures in neutral borate solution

    Thomas, S.C.; Birss, V.I. [Univ. of Calgary, Alberta (Canada). Dept. of Chemistry

    1997-10-01

    FVS0812 is a rapidly solidified Al alloy consisting of an intermetallic (dispersoid) phase, containing Al, Fe, V, and Si, surrounded by a predominantly Al matrix. The electrochemical behavior and the oxide film structure of FVS0812 were compared to that of its two phases, as well as pure Al, in neutral borate solution at a range of temperatures. While in acidic solution, FVS0812 is unable to form an adherent, thick, porous oxide film, in 60 C neutral solution, stable, although substantially thinner, porous oxides are formed on Al, FVS0812, and the matrix. In contrast to its dissolution in acidic medium, the dispersoid phase is retained within the porous film formed on the alloy in neutral solution. However, the dispersoid phase also causes the formation of a somewhat contorted porous oxide structure. Impedance measurements suggest that solution penetration into fine flaws in the barrier oxide at the barrier/porous oxide interface, a phenomenon exacerbated by increased temperature and time at applied potentials, is more prevalent for FVS0812 than for Al and the matrix.

  2. Effect of V2O5 on the dc conductivity of sodium bismuth borate glasses

    Transition metal doped quaternary glass system with composition 20Na2O-30Bi2O3-(50- x)B2O3-xV2O5 (where x = 0, 0.2, 0.3, 0.5, 2.0 mol%) has been prepared by normal melt-quench technique using analytical grade Na2CO3, Bi2O3, H3BO3, V2O5 chemicals. The main objective of present study is to investigate the effect of transition metal oxide on the conductivity mechanism of ternary alkali bismuth borate glasses. Density (D) and molar volume (VM) of each glass sample was calculated using Archimedes method. Differential scanning calorimetry (DSC) measurements were carried out at a heating rate of 10K/min for the determination of glass transition temperature Tg using Q10 DSC (TA Instruments). The values of dc conductivity and activation energy for conductivity and relaxation time have been calculated for all samples using sample dimensions. (author)

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

    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 Li2 O-MgO-B2 O3 radiation dosimeters. Copyright © 2015 John Wiley & Sons, Ltd. PMID:25828828

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

    Melo, B. M. G.; Graça, M. P. F.; Prezas, P. R.; Valente, M. A.; Almeida, A. F.; Freire, F. N. A.; Bih, L.

    2016-08-01

    In this work, phosphate-borate based glasses with molar composition 20.7P2O5-17.2Nb2O5-13.8WO3-34.5A2O-13.8B2O3, 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, σac and σdc, 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.

  5. Reddish-orange emission from Pr3+ doped zinc alumino bismuth borate glasses

    Praseodymium doped Zinc Alumino Bismuth Borate (ZnAlBiB) glasses were prepared by melt quenching technique and characterized by optical absorption and emission studies. The glassy nature of these glasses has been confirmed through XRD spectral measurements. From the absorption spectra, the Judd–Ofelt intensity parameters Ωλ (λ=2, 4 and 6) and other radiative properties like transition probability (AR), radiative lifetimes (τR) and branching ratios (βR) have been evaluated. Emission spectra were measured for different concentrations of Pr3+ ions doped glasses by exciting the glasses at 445 nm. The intensity of Pr3+ emission spectra increases from 0.1 to 1 mol% and beyond 1 mol% concentration quenching is observed. The suitable concentration of Pr3+ ions in ZnAlBiB glasses to act as a good lasing material at reddish-orange wavelength (604 nm) region has been discussed by measuring the emission cross-sections for the intense emission transition 1D2→3H4. The CIE chromaticity co-ordinates were also evaluated from the emission spectra for all the glasses to understand the suitability of these materials for reddish-orange emission. From the measured emission cross-sections and CIE chromaticity co-ordinates, it was found that 1 mol% of Pr3+ is aptly suitable for the development of visible reddish-orange lasers

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

    Boshui, Chen; Kecheng, Gu; Jianhua, Fang; Jiang, Wu; Jiu, Wang; Nan, Zhang

    2015-10-01

    Stearic acid-capped cerium borate composite nanoparticles, abbreviated as SA/CeBO3, were prepared by hydrothermal method. The morphologies, element compositions, size distributions, crystal and chemical structures, hydrophobic characteristics, of SA/CeBO3 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/CeBO3 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/CeBO3 were monodispersed nanospheres with an average diameter of 8 nm, and exhibited excellent dispersing stability in rapeseed oil. Meanwhile, SA/CeBO3 nanospheres were outstanding in enhancing friction-reducing and anti-wear capacities of rapeseed oil. The prominent tribological performances of SA/CeBO3 in rapeseed oil were attributed to the formation of a composite boundary lubrication film mainly composed of lubricous tribochemical species of B2O3, CeO2 and Fe2O3, and the adsorbates of SA/CeBO3 and rapeseed oil, on the tribo-surfaces.

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

    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/.

  8. Fabrication and optical properties of single-crystalline beta barium borate nanorods

    Single-crystalline beta barium borate (β-BaB2O4, β-BBO) nanorods with a diameter of 10-20 nm and a length up to several micrometers have been fabricated by a cetyltrimethyl ammonium bromide assisted hydrothermal method and subsequent annealing in air at 700 oC. Structure and composition characterizations were performed by X-ray powder diffraction, Fourier transform infrared spectra, Raman spectra and X-ray photoelectron spectra. The results indicate that β-BBO nanorods have an orthorhombic structure with space group of C3v-R3C. Linear and nonlinear optical properties of β-BBO nanorods were examined by the absorption spectra, photoluminescence spectra and the powders second-harmonic generation measurement. The optical characterizations indicate that β-BBO nanorods are transparent from ultraviolet to the mid-infrared regions and exhibit a strong ultraviolet emission band at 382 nm. Compared with that of urea, higher second-harmonic generation conversion efficiency of β-BBO nanorods was measured. The possible growth process of β-BBO nanorods was also discussed briefly.

  9. Characterisation and luminescence studies of Tm and Na doped magnesium borate phosphors

    In this study, structural and luminescence properties of magnesium borate of the form MgB4O7 doped with Tm and Na were investigated by X-ray diffraction (XRD), Raman spectroscopy and cathodoluminescence (CL). The morphologies of the synthetised compounds exhibit clustered granules and road-like materials. As doping trivalent ions into a host with divalent cations requires charge compensation, this effect is discussed. The CL spectra of undoped MgB4O7 shows a broad band emission centred around 350 nm which is postulated to be produced by self-trapped excitons and some other defects. From the CL emission spectrum, main emission bands centred at 360, 455, 475 nm due to the respective transitions of 1D2→3H6,1D2→3F4 and 1G4→3H6 suggest the presence of Tm3+ ion in MgB4O7 lattice site. CL mechanism was proposed to explain the observed phenomena which are valuable in possibility of the developing new luminescent materials for different applications. In addition, the experimental Raman spectrum of doped and undoped MgB4O7 were reported and discussed. - Highlights: • XRD, EDS and ESEM are used for characterizing the samples. • Broad emission band and Tm3+ 4f–4f transition peaks are discussed. • Charge compensation mechanism of MgB4O7:Tm3+, Na+ are discussed

  10. Radiation-induced processes and defects in alkali and alkaline-earth borate crystals

    The paper presents the results of a study of the radiation-induced processes and defects in nonlinear optical crystals Li2B4O7 (LTB), LiB3O5 (LBO), CsLiB6O10, KB5O8·4H2O, β-BaB2O4. It was revealed that a pulsed electron beam irradiation at 290 K forms the radiation-induced pairs of the 'vacancy--interstitial atom' defects in the cation sublattice of these crystals. This gives rise to a creation of metastable electronic (interstitial atom) and hole (small-radius polaron near the cation vacancy) centers in high concentrations. Optical hole-transitions from the local level of the trapped hole centers to the valence band states are responsible for the transient optical absorptions (TOA) of borates in the visible and UV spectral ranges. A sublattice of the weakly bound mobile lithium cations in LTB and LBO favors a spatial separation of the radiation-induced pair defects 'hole polaron near Li-vacancy--mobile interstitial Li0 atom'. Their decay rated by the electron-hole nonradiative tunnel recombination determines a peculiar feature of the TOA decay kinetics in LTB and LBO

  11. New High Capacity Cathode Materials for Rechargeable Li-ion Batteries: Vanadate-Borate Glasses

    Afyon, Semih; Krumeich, Frank; Mensing, Christian; Borgschulte, Andreas; Nesper, Reinhard

    2014-11-01

    V2O5 based materials are attractive cathode alternatives due to the many oxidation state switches of vanadium bringing about a high theoretical specific capacity. However, significant capacity losses are eminent for crystalline V2O5 phases related to the irreversible phase transformations and/or vanadium dissolution starting from the first discharge cycle. These problems can be circumvented if amorphous or glassy vanadium oxide phases are employed. Here, we demonstrate vanadate-borate glasses as high capacity cathode materials for rechargeable Li-ion batteries for the first time. The composite electrodes of V2O5 - LiBO2 glass with reduced graphite oxide (RGO) deliver specific energies around 1000 Wh/kg and retain high specific capacities in the range of ~ 300 mAh/g for the first 100 cycles. V2O5 - LiBO2 glasses are considered as promising cathode materials for rechargeable Li-ion batteries fabricated through rather simple and cost-efficient methods.

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

    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.

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

    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.

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

    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. PMID:26117746

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

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

    2015-03-01

    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. PMID:25605593

  16. Ga4B2O9: an efficient borate photocatalyst for overall water splitting without cocatalyst.

    Wang, Guangjia; Jing, Yan; Ju, Jing; Yang, Dingfeng; Yang, Jia; Gao, Wenliang; Cong, Rihong; Yang, Tao

    2015-03-16

    Borates are well-known candidates for optical materials, but their potentials in photocatalysis are rarely studied. Ga(3+)-containing oxides or sulfides are good candidates for photocatalysis applications because the unoccupied 4s orbitals of Ga usually contribute to the bottom of the conducting band. It is therefore anticipated that Ga4B2O9 might be a promising photocatalyst because of its high Ga/B ratio and three-dimensional network. Various synthetic methods, including hydrothermal (HY), sol-gel (SG), and high-temperature solid-state reaction (HTSSR), were employed to prepare crystalline Ga4B2O9. The so-obtained HY-Ga4B2O9 are micrometer single crystals but do not show any UV-light activity unless modified by Pt loading. The problem is the fast recombination of photoexcitons. Interestingly, the samples obtained by SG and HTSSR methods both possess a fine micromorphology composed of well-crystalline nanometer strips. Therefore, the excited e(-) and h(+) can move to the surface easily. Both samples exhibit excellent intrinsic UV-light activities for pure water splitting without the assistance of any cocatalyst (47 and 118 μmol/h/g for H2 evolution and 22 and 58 μmol/h/g for O2 evolution, respectively), while there is no detectable activity for P25 (nanoparticles of TiO2 with a specific surface area of 69 m(2)/g) under the same conditions. PMID:25714488

  17. Spectroscopic properties of Pr3+ ions embedded in lithium borate glasses

    Ramteke, D. D.; Swart, H. C.; Gedam, R. S.

    2016-01-01

    A series of lithium borate glasses with different Pr3+ contents were prepared by the melt quench technique to explore the new material for solid state light applications. We found that the addition of Pr3+ ions in the glass matrix has a profound effect on the properties of the glasses. The presence of Pr3+ ions in the glass matrix created various absorption bands compared to the base glass. These bands were due to the ground state (3H4) of the Pr3+ to the various excited states. Optical energy band gap was calculated by Tauc's method which showed a decreasing trend with an increase in the Pr3+ content. This might be due to structural changes when the glass structure became rigid due to the Pr3+ ions and this was confirmed by the density results. Rigidity of the glass structure was further confirmed by the Fourier transformed infrared results. The excitation spectra showed bands at 3H4→3P2, 3P1 and 3P0 nm. The 3H4→3P2 band was used to study the unresolved 1D2→3H4 and 3P0→3H6 transitions of the Pr3+ ions.

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

    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.

  19. The study on improving masonry cement for the solidification of borate wastes

    Masonry cement has been used widely as an inorganic solidification agent for the concentrated borate chemical slurry at pressurized water reactor nuclear power plants. Although masonry cement is better than Portland cement, the compressive strength does not satisfy the desired criterion of greater than 150 kg/cm2. In order to improve the conventional solidification process using masonry cement, the authors conducted research on the effects of calcium chloride and of calcium hydroxide, basically in terms of the ratio of calcium hydroxide to Portland cement. The leachability index and cumulative fractional release are also discussed. From the results, the authors have found that masonry cement is not the best binding agent unless the ratio of calcium hydroxide to cement is changed from the conventional value of 1 to a value less than 0.3. The strength of solid can then be raised from 10 kg/cm2 to a value greater than 150 kg/cm2. Calcium chloride has a negative effect on the strength of solid which was identified by both extrapolation and experiment, but has a positive effect on the leachability. 8 refs.; 3 figs.; 3 tabs

  20. Ultrasonic investigations of some bismuth borate glasses doped with Al2O3

    Yasser B Saddeek; Moenis A Azooz; Amr Bakr Saddek

    2015-02-01

    The velocities of longitudinal and transverse ultrasonic waves in different compositions of 5Al2O3–29Na2O–(66−)B2O$_{3}−x$Bi2O3 glass system were measured at 4 MHz at room temperature using the pulse-echo technique. The velocity data were used to determine the elastic moduli and the dimensionality of the studied glasses. The observed changes in the elastic moduli of the glasses were related to the modifier role of Bi2O3 content. 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 decreased the average crosslink density and the number of network bonds per unit volume along with a weakening of the different modes of vibrations, which in its turn decreased the ultrasonic velocity. Quantitative analysis was carried out using Makishima–Mackenzie model in order to obtain more information about the rigidity of these glasses.

  1. Influence of europium (Eu3+) ions on the optical properties of silver lead borate glasses

    K Keshavamurthy; B Eraiah

    2015-09-01

    The influence of europium (Eu3+) ions on the optical properties of silver lead borate glasses of the Eu2O3–(1 – )Ag2O–29PbO–70B2O3 ( = 0, 0.1, 0.2, 0.3, 0.4 and 0.5 mol%) glass system prepared by the conventional melt quenching technique and their physical and optical properties were investigated. The UV absorption spectra were recorded at room temperature in the wavelength range of 200–600 nm. From the absorption edge data, it is found that both the direct and indirect transitions and their values are ranging from 3.19 to 3.54 and 2.50 to 3.07 eV, respectively. The Urbach energy values for these glasses were found to be in the range of 0.39–0.52 eV. The refractive indices have also been evaluated with respect to different molar concentrations of Eu2O3 and their calculated values are ranging from 1.598 to 1.654.

  2. First-principles calculation of the second-harmonic-generation coefficients of borate crystals

    Duan, Chun-Gang; Li, Jun; Gu, Zong-Quan; Wang, Ding-Sheng

    1999-10-01

    We report the calculation of the second-harmonic-generation (SHG) coefficients of LiB3O5 (LBO), CsB3O5 (CBO), and BaB2O4 (BBO) using the linearized augmented plane-wave band method in the local-density approximation with a scissors operator that includes the renormalization of the momentum operator. The analysis that is based on the spectral and spatial decomposition of the calculated results reveals that, for the large component of SHG coefficients, the dominant source of the optical nonlinearities for these borate crystals is the nonlinear response of the high-lying 2p electrons of oxygen atoms, while the cations play a minor role even in the heavier Cs and Ba cases, though they dominate the conduction-band minimum. But for the small SHG component, the role of the cation became important, particularly when the isolated anionic group has little contribution due to the restriction of the symmetry. In the case of LBO and CBO, due to the linkage of anionic groups, the contributions of off-ring O atoms are almost the same as those of in-ring O atoms. Yet for BBO where there is no such linkage, the off-ring O atom plays a much more important role than the in-ring O atom does. We also find that the contribution of the virtual-hole process cannot be ignored as is usually done in the semiconductors case.

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

    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. PMID:16843052

  4. Gamma radiation shielding and optical properties measurements of zinc bismuth borate glasses

    Highlights: • 10ZnO:xBi2O3:(90−x)B2O3, (ZBB) glasses were prepared. • Radiation shielding and optical properties were investigated. • Higher 25 mol% of Bi2O3 show better shielding property compared with concretes. • ZBB glasses can develop as a Pb-free radiation shielding material. - Abstract: In this work, the zinc bismuth borate (ZBB) glasses of the composition 10ZnO:xBi2O3:(90−x)B2O3 (where x = 15, 20, 25 and 30 mol%) were prepared by the melt quenching technique. Their radiation shielding and optical properties were investigated and compared with theoretical calculations. The mass attenuation coefficients of ZBB glasses have been measured at different energies obtained from a Compton scattering technique. The results show a decrease of the mass attenuation coefficient, effective atomic number and effective electron density values with increasing of gamma-ray energies; and good agreements between experimental and theoretical values. The glass samples with Bi2O3 concentrations higher than 25 mol% (25 and 30 mol%) were observed with lower mean free path (MFP) values than all the standard shielding concretes studied. These results are indications that the ZBB glasses in the present study may be developed as a lead-free radiation shielding material in the investigated energy range

  5. Reddish-orange emission from Pr3+ doped zinc alumino bismuth borate glasses

    Mahamuda, Sk.; Swapna, K.; Srinivasa Rao, A.; Sasikala, T.; Rama Moorthy, L.

    2013-11-01

    Praseodymium doped Zinc Alumino Bismuth Borate (ZnAlBiB) glasses were prepared by melt quenching technique and characterized by optical absorption and emission studies. The glassy nature of these glasses has been confirmed through XRD spectral measurements. From the absorption spectra, the Judd-Ofelt intensity parameters Ωλ (λ=2, 4 and 6) and other radiative properties like transition probability (AR), radiative lifetimes (τR) and branching ratios (βR) have been evaluated. Emission spectra were measured for different concentrations of Pr3+ ions doped glasses by exciting the glasses at 445 nm. The intensity of Pr3+ emission spectra increases from 0.1 to 1 mol% and beyond 1 mol% concentration quenching is observed. The suitable concentration of Pr3+ ions in ZnAlBiB glasses to act as a good lasing material at reddish-orange wavelength (604 nm) region has been discussed by measuring the emission cross-sections for the intense emission transition 1D2→3H4. The CIE chromaticity co-ordinates were also evaluated from the emission spectra for all the glasses to understand the suitability of these materials for reddish-orange emission. From the measured emission cross-sections and CIE chromaticity co-ordinates, it was found that 1 mol% of Pr3+ is aptly suitable for the development of visible reddish-orange lasers.

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

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

    2014-05-01

    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. PMID:24530709

  7. Optical studies of Sm3+ ions doped Zinc Alumino Bismuth Borate glasses

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

    Zinc Alumino Bismuth Borate (ZnAlBiB) glasses doped with different concentrations of samarium (Sm3+) 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 Sm3+ 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 Sm3+ 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 4G5/2 level of Sm3+ ions. From the measured emission cross-sections, branching ratios, strong photoluminescence features and CIE chromaticity coordinates, it was found that 1 mol% of Sm3+ ions doped ZnAlBiB glasses are most suitable for the development of visible orange-red lasers.

  8. Precipitation of ZnO in Al 2O 3-doped zinc borate glass ceramics

    Masai, Hirokazu; Ueno, Takahiro; Takahashi, Yoshihiro; Fujiwara, Takumi

    2011-10-01

    Crystallization behavior of the oxide semiconductor ZnO in zinc borate glass was investigated. The precipitated crystalline phase of glass ceramics containing a small amount of Al 2O 3 was α-Zn 3B 2O 6 whereas that of the glass ceramics containing a large amount of Al 2O 3 was ZnO. It was found that the c-oriented precipitation of ZnO in a glass ceramic was brought about by the in-plane crystal growth of needle-like ZnO crystallites along the a-axis. Amount of Al 2O 3 that can make glass network affected the coordination state of B 2O 3 in the glass, and a three-coordinated BO 3 unit was preferentially formed in the glass containing a higher amount of Al 2O 3. The present results suggest that crystallization of ZnO from multi-component glass is dominated by the local coordination state of the mother glass.

  9. Waveguides and nonlinear index of refraction of borate glass doped with transition metals

    Almeida, Juliana M. P.; Fonseca, Ruben D.; De Boni, Leonardo; Diniz, Andre Rosa S.; Hernandes, Antonio C.; Ferreira, Paulo H. D.; Mendonca, Cleber R.

    2015-04-01

    The ability to write 3D waveguides by femtosecond laser micromachining and the nonlinear refractive index (n2) spectrum of a new borate glass matrix, containing zinc and lead oxides - (BZP) have been investigated. The transparent matrix was doped with transition metals (CdCl2, Fe2O3, MnO2 and CoO) in order to introduce electronic transitions in visible spectrum, aiming to evaluate their influence on the waveguides and n2 spectrum. We observed that n2 is approximately constant from 600 to 1500 nm, exhibiting an average value of 4.5 × 10-20 m2/W, which is about twice larger than the one for fused silica. The waveguide profile is influenced by the self-focusing effect of the matrix owing to its positive nonlinear index of refraction in the wavelength used for micromachining. A decrease in the waveguide loss of approximately four times was observed for the sample doped with Fe in comparison to the other ones, which may be associated with the change in the optical gap energy.

  10. Tris(thioimidazolyl)borate-zinc-thiolate complexes for the modeling of biological thiolate alkylations.

    Ibrahim, Mohamed M; Seebacher, Jan; Steinfeld, Gunther; Vahrenkamp, Heinrich

    2005-11-14

    The S3Zn-SR coordination of thiolate-alkylating enzymes such as the Ada DNA repair protein was reproduced in tris(thioimidazolyl)borate-zinc-thiolate complexes Tti(R)Zn-SR'. Four different Tti(R) ligands and nine different thiolates were employed, yielding a total of 12 new complexes. In addition, one Tti(R)Zn-SH complex and two thiolate-bridged [Tti(R)-SEt-Tti(R)]+ complexes were obtained. A selection of six thiolate complexes was converted with methyl iodide to the corresponding methyl thioethers and Tti(R)Zn-I. According to a kinetic analysis these reactions are second-order processes, which implies that the alkylations are likely to occur at the zinc-bound thiolates. They are much faster than the alkylations of zinc thiolates with N3 or N2S tripod ligands. The most reactive thiolate, Tti(Xyl)Zn-SEt, reacts slowly with trimethyl phosphate in a nonpolar medium at room temperature, yielding methyl-ethyl-thioether and Tti(Xyl)Zn-OPO(OMe)2 which can be converted back to the thiolate complex with NaSEt. This is the closest reproduction of the Ada repair process so far. PMID:16270993

  11. Production of Zinc Borate for Pilot-Scale Equipment and Effects of Reaction Conditions on Yield

    Melek BARDAKCI

    2013-05-01

    Full Text Available In this study, zinc borate (ZB was synthesized by reacting zinc oxide and boric acid in the presence of standard ZB (w/w, in terms of boric acid in order to promote crystallization. The effects of seed, H3BO3/ZnO (boric acid/zinc oxide ratio, reaction time, water volume, reaction temperature and cooling temperature on yield were investigated for pilot-scale equipment. The results indicated that the addition of seed (w/w to a saturated solution of reactants increased the yield of the reaction. The results of reaction yields obtained from either magnetically or mechanically stirred systems were compared. At various reaction times, the optimal yield was 86.78 % in a saturated aqueous solution. The products were characterized by X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FT-IR and Thermogravimetric / Differential Thermal Analysis (TG/DTA. The results displayed that ZB was successfully produced under the optimized reaction conditions and the product synthesized had high thermal stability.DOI: http://dx.doi.org/10.5755/j01.ms.19.2.4432

  12. The Preparation and Characterization of Nd2O3 Doped Borate Glass

    The Nd3+ doped borate glass of Nd2O3-MgO-ZnO-B2O3 glass system is successfully been prepared by melt-quenched technique. Batches of 15g were prepared from certified reagent grades of B2O3(99.95% purity), MgO (97%), ZnO (98% purity), and Nd2O3(99.99%). The measured glass densities are found varies from 5683.2 kgm-3 to 5724.0 kgm-3. The increment in density implies that an addition of Nd2O3 with higher atomic masses than B2O3 tend to increase the packing density of the glass structures since the atomic masses of B2O3 and Nd2O3 are 69.62 and 336.42 respectively. From the density values obtained, the molar volume of glasses was calculated. From the results, it is found that the molar volume of these glasses decreases slightly from 22.50 cm3 to 27.54 cm3 with respect to Nd2O3 content.

  13. Absorption and emission properties of Ho3+ doped lead-zinc-borate glasses

    This paper reports on the affect of lead content on the absorption and emission spectra of the Ho3+ ion doped lead-zinc-borate glasses in the composition (mol%) of (20 - x)PbO-20ZnO-(59 + x)B2O3-1.0Ho2O3 where x 0, 5,10,15 of PbO content with λ exc = 405 nm. The experimental absorption band energies have satisfactorily been correlated with the theoretical results with an r.m.s deviation of zero with the following correction factors obtained by a least square fit analysis: ΔE 1 348.495936 cm-1, ΔE 2 = 1.436043 cm-1, ΔE 3 = 46.481575 cm-1, Δξ 4f = - 28.512979 cm-1, Δα = 55.508936 cm-1, Δβ = - 1394.339908 cm-1 and Δγ 1208.424336 cm-1. By applying the Judd-Ofelt intensity parameter Ω 2 has been found to be linearly decreasing with the PbO content from 5 to 10 mol% and then increasing. And also radiative (A, A T, β, τ r) characteristic factors of the luminescent transitions (5I8 5F3,4,5 and 5S2) of the glasses have been evaluated. Stimulated emission cross-sections (σ pE) of the measured emission transitions of holmium glasses have also been computed

  14. Effect of cadmium on the structural and optical properties of sodium borate glasses

    Glasses with composition xCdO-(40-x) Na2CO3-60H3BO3 where x=10, 20, 30 and 40 mol % were prepared by conventional melt-quenching technique and hence checked by XRD technique for their amorphous nature. The density and refractive index of the samples was found to increase with the increase in content of CdO. The optical absorption spectra of the glasses was recorded in the range 200 -1100 nm and hence was used to find optical mobility gap, Urbach energy and cut-off wavelength for each sample. The decrease in optical mobility gap with increase in CdO points towards the compactness of the structure with the addition of CdO. FTIR spectroscopy reveals the presence of trigonal and tetrahedral borate units and the results indicate the conversion of BO3 to BO4 units with the increase in CdO content. It was observed that the cadmium ions enter the glass structure as network modifiers. (author)

  15. Comparison of Lithium Gadolinium Borate Crystal Shards in Scintillating and Nonscintillating Plastic Matrices

    Kazkaz, Kareem; Pedretti, Marisa

    2011-01-01

    We present a method for detecting neutrons using scintillating lithium gadolinium borate crystal shards in a plastic matrix while maintaining high gamma rejection. We have procured two cylindrical detectors, 5"\\times5", containing 1% crystal by mass. Crystal shards have a typical dimension of 1 mm. One detector was made with scintillating plastic, and one with nonscintillating plastic. Pulse shape analysis was used to reject gamma ray backgrounds. The scintillating detector was measured to have an intrinsic fast fission neutron efficiency of 0.4% and a gamma sensitivity of less than 2.3 \\times 10-9, while the nonscintillating detector had a neutron efficiency of 0.7% and gamma sensitivity of (4.75\\pm3.94)\\times10-9. We determine that increasing the neutron detection efficiency by a factor of 2 will make the detector competitive with moderated 3He tubes, and we discuss several simple and straightforward methods for obtaining or surpassing such an improvement. We end with a discussion of possible applications, ...

  16. Studies on an argon laser-induced photopolymerization employing both mono- and bischromophoric hemicyanine dye-borate complex as a photoinitiator: Part II

    Several photoredox pairs containing dichromophoric hemicyanine dyes have been evaluated as novel photoinitiators for free radical polymerization induced with an argon-ion laser irradiation. The tested photoredox couples are the pairs composed of the hemicyanine dye cations acting as electron acceptors and n-butyltriphenyl borate anions being the electron donors. The photoinitiating abilities of the series of dimmeric dichromophoric stilbazolium borates; 1,2-; 1,3-; and 1,4-bis-[4-(p-N,N-dialkylaminostyryl)pyridinyl]xylene di-n-butyltriphenylborates, were compared to the photochemistry of structurally related, monochromophoric styrylpyridinium borates. The obtained results clearly documented that the dicationic photoinitiators exhibit a marked increase in the photoinitiation ability compared to the initiators consisting of a single charged hemicyanine dye. Our studies revealed also that the rate of photopolymerization depends on ΔGel of electron transfer between borate anion and styrylpyridinium cation. The latter value was estimated for all series of styrylpyridinium borate salts. The relationship between the rate of polymerization and the free energy of activation shows the dependence predicted by the classical theory of electron transfer

  17. Studies on an argon laser-induced photopolymerization employing both mono- and bischromophoric hemicyanine dye-borate complex as a photoinitiator: Part II

    Jedrzejewska, Beata [University of Technology and Life Sciences, Faculty of Chemical Technology and Engineering, Seminaryjna 3, 85-326 Bydgoszcz (Poland)], E-mail: beata@utp.edu.pl; Marciniak, Angelika; Paczkowski, Jerzy [University of Technology and Life Sciences, Faculty of Chemical Technology and Engineering, Seminaryjna 3, 85-326 Bydgoszcz (Poland)

    2008-10-15

    Several photoredox pairs containing dichromophoric hemicyanine dyes have been evaluated as novel photoinitiators for free radical polymerization induced with an argon-ion laser irradiation. The tested photoredox couples are the pairs composed of the hemicyanine dye cations acting as electron acceptors and n-butyltriphenyl borate anions being the electron donors. The photoinitiating abilities of the series of dimmeric dichromophoric stilbazolium borates; 1,2-; 1,3-; and 1,4-bis-[4-(p-N,N-dialkylaminostyryl)pyridinyl]xylene di-n-butyltriphenylborates, were compared to the photochemistry of structurally related, monochromophoric styrylpyridinium borates. The obtained results clearly documented that the dicationic photoinitiators exhibit a marked increase in the photoinitiation ability compared to the initiators consisting of a single charged hemicyanine dye. Our studies revealed also that the rate of photopolymerization depends on {delta}G{sub el} of electron transfer between borate anion and styrylpyridinium cation. The latter value was estimated for all series of styrylpyridinium borate salts. The relationship between the rate of polymerization and the free energy of activation shows the dependence predicted by the classical theory of electron transfer.

  18. High-Pressure Synthesis of Cd(NH₃)₂[B₃O₅(NH₃)]₂: Pioneering the Way to the Substance Class of Ammine Borates.

    Sohr, Gerhard; Ciaghi, Nina; Schauperl, Michael; Wurst, Klaus; Liedl, Klaus R; Huppertz, Hubert

    2015-05-18

    To date, the access to the substance class of borates containing nitrogen, for example, nitridoborates, oxonitridoborates, or amine borates, was an extreme effort owing to the difficult starting materials and reaction conditions. Although a number of compounds containing boron and nitrogen are known, no adduct of ammonia to an inorganic borate has been observed so far. A new synthetic approach starting from the simple educts CdO, B2O3, and aqueous ammonia under conditions of 4.7 GPa and 800 °C led to the synthesis of Cd(NH3)2[B3O5(NH3)]2 as the first ammine borate. We thoroughly characterized this compound on the basis of low-temperature single-crystal and powder X-ray diffraction data, IR and Raman spectroscopy, and by quantum theoretical calculations. This contribution shows that the adduct of NH3 to the BO3 group of a complex B-O network can be stabilized, opening up a fundamentally new synthetic route to nitrogen-containing borates. PMID:25914316

  19. Low-Temperature Sintering and Microwave Dielectric Properties of Zn2SiO4 Ceramic Added with Crystalline Zinc Borate

    Chaware, Varsha; Deshmukh, Ravindra; Sarode, Chetan; Gokhale, Suresh; Phatak, Girish

    2015-07-01

    The physical and dielectric properties of composites of known microwave materials, Zn2SiO4 and Zn3B2O6, prepared by solid-state reaction, were investigated with the purpose of developing a low-loss dielectric material for low-temperature co-fired ceramic applications. An off-stoichiometric phase of Zn2SiO4 with extra SiO2 was used to avoid the occurrence of unreacted ZnO. During sintering, zinc borate was found to partially react with residual SiO2 to form Zn2SiO4. The residual zinc borate was converted to a boron-rich glassy phase which helped to reduce the sintering temperature of the composite. Good relative sintering density (>90%) at temperatures below the melting temperature of zinc borate is indicative of a sintering mechanism of diffusion-based mass transfer. Composites containing 15 wt.% zinc borate, 2.5 wt.% lithium carbonate and 20 wt.% zinc borate in zinc silicate had dielectric constants of 6.8 and 6.1, quality factors (Q×f) of 48,800 and 94,300 GHz when sintered at 900°C and 950°C, respectively. These quality factor results are close to the best values reported for zinc silicate at these sintering temperatures.

  20. Structural insights for the design of new borate-phosphates: synthesis, crystal structure and optical properties of Pb₄O(BO₃)(PO₄) and Bi₄O₃(BO₃)(PO₄).

    Wang, Ying; Pan, Shilie; Huang, Shengshi; Dong, Lingyun; Zhang, Min; Han, Shujuan; Wang, Xian

    2014-09-14

    Two new metal borate-phosphates, Pb4O(BO3)(PO4) (1) and Bi4O3(BO3)(PO4) (2), have been successfully designed and synthesized. The structures of the title compounds were determined by single-crystal X-ray diffraction. The title compounds have similar crystal structures consisting of oxygen-centered (OPb4) or (OBi4) tetrahedra as well as isolated BO3 and PO4 groups. Structural comparison and the Madelung energy calculation indicate that the title compounds also exhibit a strong correlation with the known metal borates and phosphates. In addition, a strategy of BO3-PO4 substitution is proposed for designing new borate-phosphates. Thermal analyses, IR spectroscopy and UV-vis-NIR diffuse reflectance spectroscopy have also been performed. PMID:25020047

  1. Photon-Induced Borate Groups Transformation by Femtosecond Laser%飞秒激光诱导硼酸盐基团的转变

    杨晓燕; 余昺鲲; 姜雄伟; 曾慧丹

    2003-01-01

    In this paper, we put emphasis on the analysis the mechanism of the photon-induced frequency conversionβ-BaB2O4 crystal inside a borate glass using femtosecond laser. Because of the nature of femtosecond laser's ultra-short pulse duration and high-energy deusity, in essence the laser-glass interaction mechanism is changed. Based on multiphoton ionization, collisional ionization and the network depolymerization in the borate glass, production of the plasma drives the microstructure rearrangement near the laser beam focusing area. From the structure of glass and crystal analysis, we conclude that the complicated borate groups containing BO3 and BO4 units inside the glass are converted into(B3O6) 3 anion rings.

  2. Influence of zinc borate on the mechanical properties, inflammability and dripping behavior on carbonization of radiation cross linked PVC cable insulation

    Radiation cross linked flame retardant PVC cable insulation was developed utilizing suspension PVC as resin, and by incorporating the additives namely TMPTMA, TBLS, zinc stearate, a lubricant and antimony trioxide. Vacuum package insulated wires were the exposed to gamma irradiation to achieve the desired cross linking at doses varying 40 kGy to 80 kGy. Whereas limiting oxygen index (LOI) was higher than 30 and mechanical properties of the insulation irradiated to 60 and 80 kGy were in conformity with the international standards, the insulation on carbonization demonstrated dripping behavior. To introduce anti dripping characteristic zinc borate was selected as additive because of its known ability to impart anti dripping property presumably through the information of char. It was expected that the borate might as well exert some synergistic effect on the LOI of the resultant formulation. The influence of addition of varying amount of zinc borate was thus explored on the properties mentioned and anti dripping characteristic of the radiation cross linked insulation. No detrimental or adverse effect on mechanical properties of modified formulation was observed on addition of the borate. However, a steady increase in the LOI with the absence of any flare was observed with corresponding increase in the amount of the borate. The insulation also exhibited anti dripping property at the addition of 3 phr of zinc borate and above. The formulation also has enormous market opportunities for clothing, automobile seats and interior covering where dripping of ignited materials can ignite the other floor coverings etc especially in complex, high rise and underground buildings. (Author)

  3. Effect of TiO2 on the optical, structural and crystallization behavior of barium borate glasses

    Marzouk, M. A.; ElBatal, F. H.; ElBatal, H. A.

    2016-07-01

    Collective characterizations of prepared binary barium borate glass (50 mol % BaO - 50 mol % B2O3) together with samples containing increasing added TiO2 contents (5% → 30%) were carried out by optical and FT infrared absorption measurements. FT infrared and X-ray diffraction analysis were done for heat treated glass - ceramic derivatives prepared through two step regime process. Optical spectra of the glasses reveal the presence of titanium ions mainly in the tetravalent state imparting additional UV band beside strong UV absorption due to trace iron impurity. IR spectral studies indicate the presence of triangular and tetrahedral borate groups through the modification of BaO to some BO3 to BO4 groups beside the presence of titanium ions as interfering or overlapping TiO4 or Bsbnd Osbnd Ti groupings in the glassy network. Crystalline X-ray diffraction results indicate the separation of crystalline barium borate of the composition (2BaO.5 B2O3) as a main constituent together with some crystalline alkali titanates confirming the role of TiO2 of both as nucleating agent beside acting as structural forming through reaction with alkali oxides to form crystalline titanates. The optical band gap values reveal progressive decrease and increase of Urbach energy with TiO2 content and the same for the refractive index values and all these parameters are correlated with the proposed changes in the glass constitution with the introduction of TiO2. The additional thermal expansion measurements indicate the peculiar characteristic negative expansion up to 300 °C and after which an increase in the coefficient of thermal expansion is identified with the increase in temperature. The thermal parameters are also correlated with the modification of the glass structure by the introduction of titanium ions.

  4. Synthesis, structural characterization and optical properties of a new cesium aluminum borate, Cs2Al2B2O7

    A new borate, Cs2Al2B2O7, was synthesized by solid-state reaction. It crystallizes in the monoclinic space group P21/c with a=6.719(1) Å, b=7.121(1) Å, c=9.626(3) Å, β=115.3(1)°, and Z=2. In the structure, two AlO4 tetrahedra and two BO3 planar triangles are connected alternately by corner-sharing to from nearly planar [Al2B2O10] rings, which are further linked via common O1 atom to generate layers in the bc plane. These layers then share the O3 atoms lying on a center of inversion to form a three-dimensional framework with Cs atoms residing in the channels. The IR spectrum confirms the presence of both BO3 and AlO4 groups and the UV–vis–IR diffuse reflectance spectrum indicates a band gap of about 4.13(2) eV. - Graphical abstract: A new borate, Cs2Al2B2O7, was synthesized. In the structure, BO3 triangles and AlO4 tetrahedra are connected to form a three-dimensional framework with Cs+ in the channels.▪ Highlights: ► A new borate Cs2Al2B2O7 was synthesized and crystals were obtained by flux method. ► Cs2Al2B2O7 crystallizes in a new structure type. ► Two AlO4 and two BO3 generate a [Al2B2O10] ring in the structure. ► Rings are linked to form a three-dimensional framework with Cs+ in the channels. ► Optical band gap is about 4.13 eV.

  5. Synthesis, structure, and characterization of a new rubidium cadmium borate: RbCdB3O6

    Graphical abstract: A new ternary borate, RbCdB3O6 has been synthesized and its structure was determined by single crystal X-ray diffraction for the first time. Detailed structural analyses show that RbCdB3O6 possesses the [RbCdB3O6] layers. The antiparallel arrangement of B3O6 rings makes it crystallize in the centrosymmetric group and has a relatively large birefringence. -- Highlights: • A new ternary borate, RbCdB3O6 has been synthesized. • It is a layer-type structure composed of planar B3O6 rings, which are distributed discretely from layer to layer. • A comparison of the structures of RbCdB3O6, α-BaB2O4 and β-BaB2O4 is presented. • The electronic structure and linear optical response are calculated. -- Abstract: A new ternary borate, RbCdB3O6 has been synthesized by solid-state reaction and its structure was determined by single-crystal X-ray diffraction. It crystallizes in the monoclinic space group C2/c, and in its crystal structure, RbO10 polyhedra and B3O6 rings comprise a three dimensional (3D) framework containing tunnels viewing along [1 0 1] direction in which Cd atoms are located to balance the charge. A comparison of the structures of RbCdB3O6, α-BaB2O4 and β-BaB2O4 is presented. The IR, UV–Vis-IR absorption spectra and the thermal properties of RbCdB3O6 have also been reported. The electronic structure and birefringence have been calculated by the first-principle method based on the density-functional theory

  6. Reflectance spectroscopy of low atomic weight and Na-rich minerals: Borates, hydroxides, nitrates, nitrites, and peroxides

    Cloutis, E.; Berg, B.; Mann, P.; Applin, D.

    2016-01-01

    We have measured reflectance spectra (0.35-20 μm) of a suite of minerals and synthetic compounds that contain low-Z (⩽Na) elements as the major cation and/or the major anion in oxides/oxyhydroxides, and are relevant to planetary geology and astrobiology. The suite comprises Na-borates, Na-, K-, Ca-hydroxides, nitrates, nitrites, and peroxides. Na-borate spectra exhibit B-O fundamental vibrations between 7 and 14 μm, and overtones/combinations of these bands in the 1.55, 1.75, 2.15, and 2.25 μm regions. Na-, K-, and Ca-hydroxide reflectance spectra are characterized by OH and metal-OH fundamental vibrations near 3, 8, and 18 μm, and a number of overtone and combination absorption bands at shorter wavelengths, and a characteristic metal-OH band near 2.35 μm. The nitrate and nitrite spectra exhibit fundamental N-O vibrations in the 7-14 μm region and numerous combinations and overtones that are still detectable to as low as ∼1.8 μm. Na-peroxide is largely spectrally featureless below 24 μm, making its detection problematic, while H-peroxide has many OH-related absorption features below 2.5 μm that differ in position from those of H2O ice and liquid. The results of this study indicate that the borates, hydroxides, nitrates, nitrite, and hydrogen peroxide can all be uniquely identified using characteristic absorption features that are present below 2.5 μm. However, some of these features are weak, and their detectability will depend on the types and abundances of any accessory phases that may be present.

  7. Comparative study on lithium borates as corrosion inhibitors of aluminum current collector in lithium bis(fluorosulfonyl)imide electrolytes

    Park, Kisung; Yu, Sunghun; Lee, Chulhaeng; Lee, Hochun

    2015-11-01

    Lithium bis(fluorosulfonyl)imide (LiFSI) is a promising salt that can possibly overcome the limitations of lithium hexafluorophosphate (LiPF6) in current Li-ion batteries (LIBs). Aluminum (Al) corrosion issue, however, is a major bottleneck for the wide use of LiFSI. This study investigates lithium borate salts as Al corrosion inhibitors in LiFSI electrolytes. Through a systematic comparison among lithium tetrafluoroborate (LiBF4), lithium bis(oxalato)borate (LiBOB), and lithium difluoro(oxalato)borate (LiDFOB), and LiPF6, the inhibition ability of the additives is revealed to be in the following order: LiDFOB > LiBF4 ≈ LiPF6 > LiBOB. In particular, the inhibition effect of LiDFOB is outstanding; the anodic behavior of Al in 0.8 M LiFSI + 0.2 M LiDFOB ethylene carbonate (EC)-based electrolyte is comparable to that of corrosion-free 1 M LiPF6 solution. The superior inhibition ability of LiDFOB is attributed to the formation of a passive layer composed of Al-F, Al2O3, and B-O species, as evidenced by X-ray photoelectron spectroscopy (XPS) measurements. A LiCoO2/graphite cell with 0.8 M LiFSI + 0.2 M LiDFOB electrolyte exhibits a rate capability comparable to a cell with 1 M LiPF6 solution, whereas a cell with 0.8 M LiFSI solution without LiDFOB suffers from poor power performance resulting from severe Al corrosion.

  8. High-pressure synthesis and crystal structure of the lithium borate HP-LiB3O5

    The new lithium borate HP-LiB3O5 was synthesized under high-pressure/high-temperature conditions of 6 GPa and 1050 deg. C in a multianvil press with a Walker-type module. The compound crystallizes in the space group Pnma (no. 62) with the lattice parameters a=829.7(2), b=759.6(2), and c=1726.8(4) pm (Z=16). The high-pressure compound HP-LiB3O5 is built up from a three-dimensional network of BO4 tetrahedra and BO3 groups, which incorporates Li+ ions in channels along the b-axis. Band assignments of measured IR- and Raman spectra were done via quantum-mechanical calculations. Additionally, the thermal behavior of HP-LiB3O5 was investigated. - Graphical abstract: The new high-pressure compound HP-LiB3O5 is built up from a three-dimensional network of BO4 tetrahedra and BO3 groups, which incorporates Li+ ions in channels along the b-axis. In this paper, the synthesis, the crystal structure, and the properties of HP-LiB3O5 are described. Highlights: → Synthesis of a new lithium borate with the composition HP-LiB3O5 at high pressure. → In contrast to the non-centrosymmetric phase LiB3O5, this high-pressure phase is centrosymmetric. → First example of ternary alkali borates exhibiting threefold bridging oxygen atoms.

  9. 4.7-W, 255-nm source based on second-harmonic generation of a copper-vapor laser in cesium lithium borate.

    Trickett, R I; Withford, M J; Brown, D J

    1998-02-01

    We have generated 4.7 W of UV (255-nm) radiation with wall plug efficiency of 0.12% by frequency doubling the green (511-nm) output of a kinetically enhanced medium-scale copper-vapor laser (CVL) in cesium lithium borate (CLBO). Frequency doubling in beta -barium borate produced 3.9 W of UV radiation with wall plug efficiency of 0.1%. We found that conversion was better with CLBO because of the reduced constraints on CVL beam quality, less UV absorption, and smaller UV walk-off. PMID:18084455

  10. Caractérisation de nouveaux borates pour le doublage de fréquence aux longueurs d'ondes VUV : endommagement optique

    Bourezzou, Mourad

    2013-01-01

    The purpose of my thesis, performed within the program of the ANR UV-Borate, was integrated in the UV-Conversion project certified by 2 poles of competitiveness (Matériala - Lorraine - and Route des lasers - Aquitaine -). The project concerned the study of borates YxLaySc4-(x+y)(BO3)4 (LYSB) and YAl3(BO3)4 (YAB), Non-Linear Optical (NLO) crystals which have the same crystallographic structure (R32). The growth of the crystals was realized by industrials and academics collaborators of the ANR....

  11. INVESTIGATION OF STRUCTURE-FORMATION MECHANISMS IN DIFFUSION BORATING OF WASTES WHILE PRODUCING STEEL AND IRON SHOT

    E. F. Panteleenko

    2009-01-01

    Full Text Available The paper describes development of new composite self-fluxing powders made of waste products while  producing  cast steel and iron shot.  Structure  and  properties  of  initial  and  borated  powders, dependence of boride layer thickness growth on chemical and thermal treatment time have been investigated in the paper. The paper proposes for the first time a description of structure-formation mechanism in the diffusion alloying process on the basis of the obtained data.

  12. INVESTIGATION OF STRUCTURE-FORMATION MECHANISMS IN DIFFUSION BORATING OF WASTES WHILE PRODUCING STEEL AND IRON SHOT

    E. F. Panteleenko

    2014-01-01

    The paper describes development of new composite self-fluxing powders made of waste products while  producing  cast steel and iron shot.  Structure  and  properties  of  initial  and  borated  powders, dependence of boride layer thickness growth on chemical and thermal treatment time have been investigated in the paper. The paper proposes for the first time a description of structure-formation mechanism in the diffusion alloying process on the basis of the obtained data.

  13. Influences of dysprosium and phosphorous oxides co-doping on thermoluminescence features and kinetic parameters of lithium magnesium borate glass

    This paper presents the main dosimetric characteristics and kinetic parameters of a newly proposed borate glass dosimeter modified with lithium and magnesium oxide (LMB) and co-doped with Dy2O3 and P2O5. Dosimetric features include thermoluminescence (TL) glow-curve, annealing procedure, TL sensitivity, photon dose response, fading, reproducibility, minimum detectable dose, kinetics order, activation energy (E) and frequency factor (s). The proposed dosimeter exhibits simple glow curves, good linearity from 0.01 up to 4 Gy, easy annealing, excellent reproducibility and minimal fading. These attractive features will pave the way to its use in radiation dosimetry. (author)

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

    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

  15. Luminescent thermochromism in potassium-alumina-borate glass with copper-containing molecular clusters at elevated temperatures

    Babkina, Anastasiya N.; Nikonorov, Nikolaij V.; Shakhverdov, Teimur A.; Shirshnev, Pavel S.; Sidorov, Alexander I.

    2014-02-01

    It is experimentally shown that a considerable luminescent thermochromic effect occurs in potassium-alumina-borate (PAB) glasses with copper-containing molecular clusters. This effect is manifested in a reversible blue spectral shift of luminescence band about 100 nm and its narrowing, with negligible change of luminescence amplitude in maximum during heating from 20 up to 300 °C. Luminescence and excitation spectra of PAB glass at different temperatures are presented. It is shown that the temperature rise results in a red spectral shift of excitation bands and in their broadening.

  16. Nonresonant x-ray magnetic scattering on rare-earth iron borates $RFe_3(BO_3)_4$

    Hamann-Borrero, J. E.; M. Philipp; Kataeva, O.; v Zimmermann, M.; Geck, J.; Klingeler, R.; A. Vasiliev; Bezmaternykh, L.; Büchner, B.; Hess, C

    2010-01-01

    Hard x-ray scattering (HXS) experiments with a photon energy of 100keV were performed as a function of temperature and applied magnetic field on selected compounds of the RFe$_3$(BO$_3$)$_4$ family. The results show the presence of several unexpected diffraction features, in particular non-resonant magnetic reflections in the magnetically ordered phase, and structural reflections that violate the diffraction conditions for the low temperature phase $P3_121$ of the rare-earth iron borates. The...

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

    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

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

    Singh, Vishwanath P.; Badiger, N. M.

    2014-01-01

    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 energ...

  19. Bismuth and zinc double borate in Bi2O3-B2O3-ZnO system

    On the basis of DTA and X-ray phase analysis data phase diagram of 2Bi2O3xB2O3-ZnO system is plotted. Bismuth and zinc double borate 2Bi2O3xZnOxB2O3 is stated to be formed. It belongs to a monoclinic crystal system. All elementary cell parameters: a=16.43(8), b=10.27(6), c=5.607(3) A, β=95 ± 1, z=4 are determined

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

    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

  1. Thermal-heating CVD synthesis of BN nanotubes from trimethyl borate and nitrogen gas

    Lin, F.-H. [Institute of Biomedical Engineering, College of Medicine and College of Engineering, National Taiwan University Hospital, National Taiwan University, Taipei 106, Taiwan (China); Hsu, C.-K. [Department of Materials and Mineral Resources Engineering, National Taipei University of Technology, Taipei 106, Taiwan (China)], E-mail: double@ha.mc.ntu.edu.tw; Tang, T.-P. [Department of Materials and Mineral Resources Engineering, National Taipei University of Technology, Taipei 106, Taiwan (China); Kang, P.-L. [Department of Surgery, Kaoshiung Veterans General Hospital, Taiwan (China); Yang, F.-F. [Department of Materials and Mineral Resources Engineering, National Taipei University of Technology, Taipei 106, Taiwan (China)

    2008-01-15

    Boron nitride (BN) is one of III-V compounds widely applied on the electrical industry. It has been fabricated by numerous techniques, but so far there is no reliable method to produce pure and high-yielding BN nanotubes at relatively lower temperature. Therefore, the exploration on its synthesis is still a challenging subject. In the study, the BN nanotube would be synthesized by thermal-heating chemical vapor deposition (TH-CVD) with trimethyl borate evaporated at 60 deg. C and nitrogen gas flew into reaction chamber as the source of B and N, respectively. 434 stainless steel wires will be coiled as an entangled wire scaffold with pore size of 1 mm and then placed in the middle part of reaction chamber. The metallic ions contained in the stainless steel will serve as the catalysts for of BN nanotube in situ growth. From the results of SEM, HRTEM, FTIR and XRD analysis, hexagonal-BN (h-BN) and orthorhombic-BN (o-BN) nanotubes were successfully synthesized at relatively low temperature between 1000 and 1200 deg. C. All the nanotubes prepared in the system were identified as h-BN and o-BN. At reaction temperature of 1200 deg. C, several types of BN morphology appeared. The BN nanotubes could be obtained at the temperature between 1000 and 1100 deg. C. However, BN nanotubes for the latter temperature grow into larger size tube. The optimum reaction temperature for BN nanotube synthesis is 1000 deg. C. The reproduction property of synthesized BN nanotube by this method is very promising. The method should have a great potential to prepare BN nanotube in the future.

  2. Dysprosium lithium borate glass mircrospheres for radiation synovectomy: The in vitro and in vivo performance evaluation

    The radioactive dysprosium lithium borate glass (DyLB) microspheres with different glass compositions were prepared for radiation synovectomy. The biodegradability and biocompatibility of these DyLB microspheres were evaluated in vitro and in vivo. The DyLB microspheres studied in this work were partially biodegradable in a simulated body fluid (SBF), with the final weight loss of the microspheres in the range of 24.6% and 55.0% (wt.%) after 8 days of immersion. The ICP results revealed that the dissolution of lithium significantly decreased from 100% to 53.7% with increasing content of Dy2O3 in the microspheres from 18% to 22% (wt.%, from S-1 to S-3). However, for all of the three samples, nearly all of the dysprosium (> 99.997%, wt.%) remained in the microspheres, in the form of insoluble phosphates and carbonates, which was proved by the SEM and EDX analyses. The degradation of DyLB microspheres in SBF gradually decreased with immersion time and eventually reached equilibrium after 7 days of immersion. Compared to the other two samples, the S-3 sample with the lowest Dy3+ dissolution (about 0.002%) was considered more secure for clinical application. Furthermore, the S-3 DyLB microspheres exhibited good biocompatibility, since neither tissue damage nor inflammation was observed, after they were implanted in the liver of rat for two weeks. After neutron activation, the radionuclide purity of radioactive S-3 DyLB microspheres was 99.999%, which were suitable for radiation synovectomy.

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

    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 CeO2 are extensively studied for scintillating applications. Radiation length of CeO2 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 15Li2O-xCeO2-(85''x)B2O3 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 CeO2. 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 CeO2. The radiation length was determined using density values and it was found to decrease with the addition of CeO2. 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 (EgOpt) decreases with the addition of CeO2

  4. Preparation and Tribological Behavior of Hydrophobic Lanthanum Borate Nanosheets in Rapeseed Oil

    Gu Kecheng; Chen Boshui; Xue Ming; Wang Jiu; Fang Jianhua; Wu Jiang

    2016-01-01

    Oleic acid-capped lanthanum borate (abbreviated as OA/LaBO3·H2O) nanosheets were prepared by the hydrothermal method. The microstructures of as-prepared OA/LaBO3·H2O were characterized by means of SEM, TEM, EDS, FTIR and XRD, respectively. Moreover, the friction and wear properties of OA/LaBO3·H2O as a lubricant additive in rapeseed oil were evaluated on a four-ball tribotester. The tribochemical characteristics of worn surfaces were investigated by SEM and XPS. The results showed that the hydrophobic OA/LaBO3·H2O nanosheets exhibited their morphology with a diameter in the range of 100 nm to 300 nm and a thickness of about 25 nm, and displayed excellent dispersing stability in rapeseed oil. In the meantime, the rapeseed oil doped with OA/LaBO3·H2O nanosheets markedly decreased the friction and wear of steel balls, and the optimal friction-reducing and antiwear ability of rapeseed oil was obtained at an OA/LaBO3·H2O content of 1.0%. The outstanding tribological performance of OA/LaBO3·H2O in rapeseed oil was attributed to the formation of a composite boundary lubrication iflm mainly composed of lubricious tribochemical species of B2O3, La2O3 and Fe2O3, and deposits of OA/LaBO3·H2O nanosheets as well as the adsorbates of rapeseed oil on rubbed surfaces.

  5. Thermoluminescence and defect centres in Tb doped lithium magnesium borate phosphor

    Menon, S.N., E-mail: sanju_n_m@yahoo.com [Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Trombay, Mumbai (India); Kadam, Sonal [Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Trombay, Mumbai (India); Watanabe, S.; Gundu Rao, T.K. [Institute of Physics, University of Sao Paulo, 05508-090 Sao Paulo, SP (Brazil); Kulkarni, M.S.; Babu, D.A.R. [Radiological Physics and Advisory Division, Bhabha Atomic Research Centre, Trombay, Mumbai (India)

    2015-11-15

    Terbium doped lithium magnesium borate phosphor exhibits thermoluminescence (TL) peaks at about 140 °C, 200 °C, 225 °C and 370 °C. The phosphor was characterized by X-ray powder diffraction and photoluminescence studies. Electron Spin Resonance (ESR) studies were carried out to identify the defect centres responsible for the TL peaks. Room temperature ESR spectrum of irradiated phosphor appears to be a superposition of two distinct centres. One of the centres (centre I) with principal g-value 2.0108 is identified as an O{sup −} ion and the centre correlates with the TL peak at 200 °C. Centre II with an isotropic g-factor 2.0029 is assigned to an F{sup +}-type centre (singly ionized oxygen vacancy) and is the likely recombination centre for the TL peaks at 200 °C and 225 °C. An additional defect centre is observed during thermal annealing experiments and this centre (assigned to F{sup +} centre) seems to originate from an F centre (oxygen vacancy with two electrons). This F centre may be related to the observed high temperature 370 °C TL peak in LiMgBO{sub 3}:Tb phosphor. - Highlights: • Powder phosphor of LiMgBO{sub 3}:Tb{sup 3+} was prepared by solid state diffusion method. • The phosphor exhibits a dominant emission at 545 nm ({sup 5}D{sub 4}→{sup 7}F{sub 5}) of the Tb{sup 3+} ion. • Electron Spin Resonance studies have been carried out to identify the defect centres responsible for the observed thermoluminescence peaks.

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

    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. PMID:25366812

  7. Visible luminescence characteristics of Sm{sup 3+} doped Zinc Alumino Bismuth Borate glasses

    Swapna, K.; Mahamuda, Sk. [Department of Physics, K L University, Green Fields, Vaddeswaram 522502, AP (India); Rao, A. Srinivasa, E-mail: drsrallam@yahoo.co.in [Department of Physics, K L University, Green Fields, Vaddeswaram 522502, AP (India); Department of Applied Physics, Delhi Technological University, Delhi 110042 (India); Sasikala, T.; Moorthy, L. Rama [Department of Physics, S V University, Tirupathi 517502, AP (India)

    2014-02-15

    Zinc Alumino Bismuth Borate (ZnAlBiB) glasses at different compositions doped with 1 mol% of Sm{sup 3+} ions were prepared by using the melt quenching technique and investigated by XRD, optical absorption, emission and decay curve analysis to understand the visible luminescence of these glasses. From the absorption spectra the JO parameters are evaluated and are used to calculate the radiative properties such as transition probability, radiative lifetime, branching ratio and absorption cross-sections for various fluorescent levels of Sm{sup 3+} ions. The emission spectra of Sm{sup 3+} ions doped ZnAlBiB glasses show two intense emission bands {sup 4}G{sub 5/2}→{sup 6}H{sub 7/2} (orange) and {sup 4}G{sub 5/2}→{sup 6}H{sub 9/2} (red) for which the stimulated emission cross-section and branching ratios are evaluated to understand the potentiality of these materials as visible lasers. The decay profiles for the {sup 4}G{sub 5/2} fluorescent level of Sm{sup 3+} doped ZnAlBiB glasses have been recorded to measure the quantum efficiency (η) of these glasses. The strong visible emissions, large stimulated emission cross-sections, high branching ratios and good quantum efficiencies observed for the present ZnAlBiB glasses suggest the suitability of these glasses as laser and photonic devices operating in visible region. -- Highlights: • Sm{sup 3+} doped ZnAlBiB glasses have been synthesised using melt quenching technique. • JO theory has been applied to evaluate the radiative properties of Sm{sup 3+} doped ZnAlBiB glasses. • Emission cross-sections have been evaluated for the intense emission transitions. • Quantum efficiency of the ZnAlBiB glasses was measured to understand the suitability of these glasses for lasers.

  8. Reddish-orange emission from Pr{sup 3+} doped zinc alumino bismuth borate glasses

    Mahamuda, Sk., E-mail: mahamuda.ss@gmail.com [Department of Physics, KL University, Green Fields, Vaddeswaram 522502, AP (India); Swapna, K., E-mail: kswapna80@gmail.com [Department of Physics, KL University, Green Fields, Vaddeswaram 522502, AP (India); Srinivasa Rao, A., E-mail: drsrallam@yahoo.co.in [Department of Physics, KL University, Green Fields, Vaddeswaram 522502, AP (India); Department of Applied Physics, Delhi Technological University, New Delhi 110042 (India); Sasikala, T.; Rama Moorthy, L. [Department of Physics, SV University, Tirupathi 517502, AP (India)

    2013-11-01

    Praseodymium doped Zinc Alumino Bismuth Borate (ZnAlBiB) glasses were prepared by melt quenching technique and characterized by optical absorption and emission studies. The glassy nature of these glasses has been confirmed through XRD spectral measurements. From the absorption spectra, the Judd–Ofelt intensity parameters Ω{sub λ} (λ=2, 4 and 6) and other radiative properties like transition probability (A{sub R}), radiative lifetimes (τ{sub R}) and branching ratios (β{sub R}) have been evaluated. Emission spectra were measured for different concentrations of Pr{sup 3+} ions doped glasses by exciting the glasses at 445 nm. The intensity of Pr{sup 3+} emission spectra increases from 0.1 to 1 mol% and beyond 1 mol% concentration quenching is observed. The suitable concentration of Pr{sup 3+} ions in ZnAlBiB glasses to act as a good lasing material at reddish-orange wavelength (604 nm) region has been discussed by measuring the emission cross-sections for the intense emission transition {sup 1}D{sub 2}→{sup 3}H{sub 4}. The CIE chromaticity co-ordinates were also evaluated from the emission spectra for all the glasses to understand the suitability of these materials for reddish-orange emission. From the measured emission cross-sections and CIE chromaticity co-ordinates, it was found that 1 mol% of Pr{sup 3+} is aptly suitable for the development of visible reddish-orange lasers.

  9. Visible luminescence characteristics of Sm3+ doped Zinc Alumino Bismuth Borate glasses

    Zinc Alumino Bismuth Borate (ZnAlBiB) glasses at different compositions doped with 1 mol% of Sm3+ ions were prepared by using the melt quenching technique and investigated by XRD, optical absorption, emission and decay curve analysis to understand the visible luminescence of these glasses. From the absorption spectra the JO parameters are evaluated and are used to calculate the radiative properties such as transition probability, radiative lifetime, branching ratio and absorption cross-sections for various fluorescent levels of Sm3+ ions. The emission spectra of Sm3+ ions doped ZnAlBiB glasses show two intense emission bands 4G5/2→6H7/2 (orange) and 4G5/2→6H9/2 (red) for which the stimulated emission cross-section and branching ratios are evaluated to understand the potentiality of these materials as visible lasers. The decay profiles for the 4G5/2 fluorescent level of Sm3+ doped ZnAlBiB glasses have been recorded to measure the quantum efficiency (η) of these glasses. The strong visible emissions, large stimulated emission cross-sections, high branching ratios and good quantum efficiencies observed for the present ZnAlBiB glasses suggest the suitability of these glasses as laser and photonic devices operating in visible region. -- Highlights: • Sm3+ doped ZnAlBiB glasses have been synthesised using melt quenching technique. • JO theory has been applied to evaluate the radiative properties of Sm3+ doped ZnAlBiB glasses. • Emission cross-sections have been evaluated for the intense emission transitions. • Quantum efficiency of the ZnAlBiB glasses was measured to understand the suitability of these glasses for lasers

  10. Tb3+ doped Zinc Alumino Bismuth Borate glasses for green emitting luminescent devices

    Zinc Alumino Bismuth Borate (ZnAlBiB) glasses doped with terbium (Tb3+) ions with a chemical composition 20ZnO–10Al2O3–(10−x)Bi2O3–60B2O3−xTb2O3 (x=0.1, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 mol%) were prepared by a conventional melt quenching method and studied their optical absorption, photoluminescence and decay spectral properties. The Judd–Ofelt (J–O) parameters evaluated from the experimental oscillator strengths were used to measure the radiative properties for the prominent luminescent transitions of Tb3+ ions such as 5D4→7F6, 7F5, 7F4 and 7F3. The effect of Tb3+ ion concentration on the luminescence process observed in the visible region was discussed in detail. The emission spectra recorded for all the ZnAlBiB glasses doped with Tb3+ ions, show an intense peak in green region at 542 nm. The stimulated emission cross-section, branching ratios and quantum efficiency values evaluated for green emission (5D4→7F5) suggests the utility of these glasses for green luminescence applications. It was found that, within the concentration range investigated, 2.5 mol% of Tb3+ doped ZnAlBiB glass is most suitable for green luminescence applications at 542 nm in principle. - Highlights: • ZnAlBiB glasses doped with Tb3+ ions were prepared by a conventional melt quenching technique. • Judd–Ofelt and radiative properties are measured from the emission spectra. • Quantum efficiency of the ZnAlBiB glasses is measured by using radiative and measured lifetimes. • CIE Chromaticity co-ordinates are evaluated from emission spectra

  11. Luminescence characterization of Eu3+ doped Zinc Alumino Bismuth Borate glasses for visible red emission applications

    Zinc Alumino Bismuth Borate (ZnAlBiB) glasses doped with different concentrations of Eu3+ ions have been prepared by rapid melt quenching technique and characterized for their luminescence behavior through various spectroscopic techniques such as absorption, excitation, emission, decay profiles and confocal image measurements at room temperature. From the measured absorption spectra, the bonding parameters (δ) were evaluated to find the nature of bonding between Eu3+ ions with its surrounding ligands in these ZnAlBiB glasses. The emission spectra of Eu3+ ions in ZnAlBiB glasses excited at 410 nm (CW laser) show the characteristic of Eu3+ ions with more intense visible red emission corresponding to 5D0→7F2 transition. This intense visible red emission is further confirmed by the confocal luminescence images recorded for all the ZnAlBiB glasses. Judd–Ofelt (J–O) parameters estimated from the emission spectral information are used to estimate the important radiative properties such as transition probability (AR), branching ratios (βR) and emission-cross sections for the prominent emission levels. The large stimulated emission cross-sections and branching ratios observed for ZnAlBiB glasses suggest the utility of these glasses in visible red region of the electromagnetic spectrum. The CIE chromaticity coordinates evaluated from the emission spectra and the confocal images recorded for all the ZnAlBiB glasses also indicates that, these glasses at higher concentration of Eu3+ ions are aptly suitable for intense red emission at 613 nm corresponding to 5D0→7F2 transition. - Highlights: • ZnAlBiB glasses doped with Eu3+ ions were prepared by conventional melt quenching technique. • Radiative properties are measured from the emission spectra. • Quantum efficiency of the ZnAlBiB glasses is measured by using radiative and measured lifetimes. • CIE Chromaticity coordinates are evaluated from emission spectra

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

    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.

  13. Spectroscopic and structural investigations of Er3+ doped zinc bismuth borate glasses

    Highlights: ► Spectral properties of Er3+ doped zinc bismuth borate glasses have been analyzed. ► Judd–Ofelt intensity parameters have been evaluated from absorption bands. ► Red shift in peak wavelength with Bi2O3 is attributed to the nephlauxetic effect. ► The large value of σT reflects the suitability of glasses in amplifier devices. ► These glasses have high radiative quantum efficiency. - Abstract: Erbium doped glasses having composition 20ZnO·xBi2O3·(79.5 − x)B2O3 (15 ≤ x ≤ 35, x in mol%) were prepared by melt-quench technique. The spectroscopic properties were investigated using optical absorption and fluorescence spectra. The Judd–Ofelt intensity parameters, Ωλ (λ = 2, 4, 6) were determined from the spectral intensities of absorption bands in order to calculate the radiative transition probability (AR), radiative life time (τR), branching ratio (βR) for various excited luminescent states. Using the emission spectra, full width at half maximum (FWHM), stimulated emission cross-section (σe) and figure of merit (FOM) were evaluated. The high values of Judd–Ofelt parameters indicate a substantial mixing of other electronic configuration into the 4fN configuration by the random crystal field in the glasses. All the intensity parameters (Ωλ) decrease with increase in Bi2O3 content and the effect is found to be most pronounced for Ω2 values. The structural investigations of the glasses were carried out by recording the IR transmission spectra. A correlation between the network forming units with the multi-phonon relaxation rate and hence with the possibility of radiative quantum efficiency has been made. In addition, various physical and optical parameters have been determined from the measured density and refractive index values.

  14. In vitro evaluation of borate-based bioactive glass scaffolds prepared by a polymer foam replication method

    Borate-based bioactive glass scaffolds with a microstructure similar to that of human trabecular bone were prepared using a polymer foam replication method, and evaluated in vitro for potential bone repair applications. The scaffolds (porosity = 72 ± 3%; pore size = 250-500 μm) had a compressive strength of 6.4 ± 1.0 MPa. The bioactivity of the scaffolds was confirmed by the formation of a hydroxyapatite (HA) layer on the surface of the glass within 7 days in 0.02 M K2HPO4 solution at 37 deg. C. The biocompatibility of the scaffolds was assessed from the response of cells to extracts of the dissolution products of the scaffolds, using assays of MTT hydrolysis, cell viability, and alkaline phosphatase activity. For boron concentrations below a threshold value (0.65 mM), extracts of the glass dissolution products supported the proliferation of bone marrow stromal cells, as well as the proliferation and function of murine MLO-A5 cells, an osteogenic cell line. Scanning electron microscopy showed attachment and continuous increase in the density of MLO-A5 cells cultured on the surface of the glass scaffolds. The results indicate that borate-based bioactive glass could be a potential scaffold material for bone tissue engineering provided that the boron released from the glass could be controlled below a threshold value.

  15. Er-doped lead borate glasses and transparent glass ceramics for near-infrared luminescence and up-conversion applications.

    Pisarski, Wojciech A; Goryczka, Tomasz; Pisarska, Joanna; Ryba-Romanowski, Witold

    2007-03-15

    Lead borate based glasses have been analyzed using Raman and infrared spectroscopy. The formation of different borate groups and the direction of BO3 BO4 conversion strongly depends on the PbO- and/or PbF2-to-B2O3 ratio in chemical composition. PbF2-PbO-B2O3 based glasses containing Er3+ ions have been studied after annealing. The orthorhombic PbF2 crystallites are formed during thermal treatment, which was evidenced by X-ray diffraction analysis. Near-infrared luminescence at 1530 nm and green up-conversion at 545 nm have been registered for samples before and after annealing. The luminescence bands correspond to 4I13/2-4I15/2 and 4S3/2-4I15/2 transitions of Er3+ ions, respectively. In comparison to the precursor glasses, the luminescence intensities are higher in the studied transparent oxyfluoride glass ceramics. Simultaneously, the half-width of the luminescence lines slightly decreases. It can be the evidence that a small amount of the Er3+ ions is incorporated into the orthorhombic PbF2 phase. PMID:17302452

  16. Borate complexes of x-ray iodinated contrast agents: characterization and sorption studies for their removal from aqueous media.

    Rustighi, Isabella; Donati, Ivan; Ferluga, Matteo; Campa, Cristiana; Pasqua, Adele E; Rossi, Marco; Paoletti, Sergio

    2012-02-29

    Iodinated contrast media (ICM) are persistent and ubiquitous water pollutants. Because of their high water solubility and biochemical stability, their phase-separation and recovery from the aquatic environment is very difficult. Here, borate was chosen as a complexing agent of the two diagnostic aids iomeprol and iopamidol in order to provide them with a negative charge and to fix the resulting adducts on Dowex 1X4 ion exchangers. A systematic characterization study of the complex by means of capillary zone electrophoresis and 11B NMR revealed that iomeprol and iopamidol interact with borate anions in aqueous solutions giving a 1:1 single-charged adduct and that the association constant at 25 °C for both contrast agents is highest at pH 10.5. These findings allowed the proper calibration of experimental parameters for further batch adsorption-desorption trials, where the two ICM were shown to be almost completely removed from the water phase and released from the solid sorbents in mild conditions, enabling the recovery of functional resin. PMID:22245510

  17. In vitro evaluation of borate-based bioactive glass scaffolds prepared by a polymer foam replication method

    Fu Hailuo, E-mail: fuhailuo@hotmail.com [Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO 65409 (United States); Institute of Bio-Engineering and IT Materials, Tongji University, Shanghai 200092 (China); Fu Qiang, E-mail: fuharry@hotmail.com [Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO 65409 (United States); Zhou Nai [Institute of Bio-Engineering and IT Materials, Tongji University, Shanghai 200092 (China); Huang Wenhai, E-mail: whhuang@mail.tongji.edu.cn [Institute of Bio-Engineering and IT Materials, Tongji University, Shanghai 200092 (China); Rahaman, Mohamed N. [Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO 65409 (United States); Wang Deping [Institute of Bio-Engineering and IT Materials, Tongji University, Shanghai 200092 (China); Liu Xin [Department of Materials Science and Engineering, Missouri University of Science and Technology, Rolla, MO 65409 (United States); Institute of Bio-Engineering and IT Materials, Tongji University, Shanghai 200092 (China)

    2009-08-31

    Borate-based bioactive glass scaffolds with a microstructure similar to that of human trabecular bone were prepared using a polymer foam replication method, and evaluated in vitro for potential bone repair applications. The scaffolds (porosity = 72 {+-} 3%; pore size = 250-500 {mu}m) had a compressive strength of 6.4 {+-} 1.0 MPa. The bioactivity of the scaffolds was confirmed by the formation of a hydroxyapatite (HA) layer on the surface of the glass within 7 days in 0.02 M K{sub 2}HPO{sub 4} solution at 37 deg. C. The biocompatibility of the scaffolds was assessed from the response of cells to extracts of the dissolution products of the scaffolds, using assays of MTT hydrolysis, cell viability, and alkaline phosphatase activity. For boron concentrations below a threshold value (0.65 mM), extracts of the glass dissolution products supported the proliferation of bone marrow stromal cells, as well as the proliferation and function of murine MLO-A5 cells, an osteogenic cell line. Scanning electron microscopy showed attachment and continuous increase in the density of MLO-A5 cells cultured on the surface of the glass scaffolds. The results indicate that borate-based bioactive glass could be a potential scaffold material for bone tissue engineering provided that the boron released from the glass could be controlled below a threshold value.

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

    Lithium potassium borate (LKB) glasses co-doped with TiO2 and MgO were prepared using the melt quenching technique. The glasses were cut into transparent chips and exposed to gamma rays of 60Co 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 (Zeff=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 103 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

  19. In-situ Quasi-Instantaneous e-beam Driven Catalyst-Free Formation Of Crystalline Aluminum Borate Nanowires

    Gonzalez-Martinez, Ignacio G.; Gemming, Thomas; Mendes, Rafael; Bachmatiuk, Alicja; Bezugly, Viktor; Kunstmann, Jens; Eckert, Jürgen; Cuniberti, Gianaurelio; Rümmeli, Mark H.

    2016-03-01

    The catalyst-assisted nucleation and growth mechanisms for many kinds of nanowires and nanotubes are pretty well understood. At times, though, 1D nanostructures form without a catalyst and the argued growth modes have inconsistencies. One such example is the catalyst-free growth of aluminium borate nanowires. Here we develop an in-situ catalyst-free room temperature growth route for aluminium nanowires using the electron beam in a transmission electron microscope. We provide strong experimental evidence that supports a formation process that can be viewed as a phase transition in which the generation of free-volume induced by the electron beam irradiation enhances the atomic mobility within the precursor material. The enhanced atomic mobility and specific features of the crystal structure of Al5BO9 drive the atomic rearrangement that results in the large scale formation of highly crystalline aluminium borate nanowires. The whole formation process can be completed within fractions of a second. Our developed growth mechanism might also be extended to describe the catalyst-free formation of other nanowires.

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

    Highlights: • Fe and large-ion-radius elements (Y, Bi, Pb, and Sm) co-doped borate glasses were prepared. • Maghemite, γ-Fe2O3, 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-Fe2O3, 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-Fe2O3 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

  1. Displacement damage from particle radiation in yttrium borate phosphor doped with cerium(III) or europium(III)

    This study investigates whether particle irradiation of yttrium borate doped with cerium(III) (YBO3:1%Ce3+) and yttrium borate doped with europium(III) (YBO3:6%Eu3+) can cause displacement damage and whether photoluminescent emission changes with the radiation dose. Although phosphors scintillate upon irradiation, of more interest in this study are the permanent changes caused by non-ionizing energy absorption, which alters the environment of the luminescent centers and thus the luminescence. Photoluminescence spectroscopy indicates that the emission intensity of both YBO3:1%Ce3+ and YBO3:6%Eu3+ decreases with increasing proton fluence. The sensitivity of changes in the emission intensity to proton fluence is 5 times more in the europium-doped samples than in the cerium-doped samples. -- Author-Highlights: • Lattice damage from 5 MeV alpha irradiation cannot be detected up to a fluence of 1016 cm−2 in YBO:Ce or YBO:Eu. • Lattice damage from 1 MeV protons in YBO:Ce and YBO:Eu is significant and can be detected using PL. • The Eu-doped samples appear to be slightly more sensitive to protons than Ce-doped samples of YBO, which is contrary to our original hypothesis. • The degradation is likely due to changes in the of the lattice rather than quenching of the luminescent centers

  2. Characterization of chemically sprayed CdO films on borate and phosphate glass substrates produced by melt-quenching technique

    The properties of substrates used to deposit thin films are an important parameter in thin film production. Instead of using a commercial substrate, in this work, borate and phosphate glasses have been obtained by classic melt-quenching technique to be used as substrates for CdO films. Also, a microscope glass substrate has been used to compare the coating properties by other glass substrates. All films have been produced by Ultrasonic Spray Pyrolysis technique. The substrate temperature has been selected as 275 ± 5 °C. Thicknesses and some optical parameters such as refractive index and extinction coefficient have been determined by spectroscopic ellipsometry. Absorbance and transmittance spectra have been taken by UV/VIS spectrophotometer. Four-probe method has been used to determine the electrical resistivity values of the films. XRD investigations have shown that type of the substrate dramatically affects the characteristics of CdO films. CdO film deposited on phosphate glass substrate has the best structural quality. Atomic Force Microscope has been used to investigate the surface properties and roughness values of the films. - Highlights: ► Borate/phosphate glasses were prepared by melt-quenching and used as substrates. ► Alternative, low resistive CdO films were deposited by an economical technique. ► A low refractive index (by Spectroscopic Ellipsometry) CdO film was obtained

  3. Contribution of Eu ions on the precipitation of silver nanoparticles in Ag-Eu co-doped borate glasses

    Graphical abstract: - Highlights: • Silver nanoparticles are precipitated from the borate glasses during the melting process without any further heat treatment. • The reduction of Eu3+ ions to Eu2+ ions is presented in this material. • The intensity of Ag+ luminescence. • The introduction of Eu ions accelerated the reaction between Eu2+ ions and silver ions inducing the silver clusters formation. - Abstract: Ag+ doped sodium borate glasses with different Eu ions concentration were prepared by the melt-quenching method. The absorption at about 410 nm which was caused by the surface plasmon resonance (SPR) of Ag nanoparticles (NPs) is promoted with increasing of Eu ions concentration. Meanwhile, the luminescent spectra showed that the emission intensity of Ag+ decreased while that of the Ag aggregates increased simultaneously. The results indicated that the Ag ions intend to form the high-polymeric state such as Ag aggregates and nanoparticles with increasing of europium ions. Owing to the self-reduction of Eu3+ to Eu2+ in our glass system, it revealed that Ag+ has been reduced by the neighboring Eu2+ which leads to the formation of Ag aggregates and the precipitation of Ag NPs in the matrix. In addition, energy transfer (ET) process from Ag+/Ag aggregates to the Eu3+ was investigated for the enhancement of Eu3+ luminescence

  4. An experimental study on the leaching of borate waste and spent resin waste forms in a simulated sea water

    In general, leaching test is performed and mostly employed in the acceptance criteria for radioactive waste disposal and is considered very important because the rate of release of radionuclides from a waste form is one of the most important parameter in defining and evaluating the radionuclide source term in the disposal environment. NRC strongly recommended that the chosen leachant should be the most aggressive one. Therefore it is considered that the certain results of the leaching test should supply the information to evaluate the radionuclide source term and the basis to determine the most aggressive leachant in the leaching test. In this study, leaching test of borate waste and spent resin waste forms is performed in order to compare the leaching characteristics of the waste forms in a simulated sea-water with those in a distilled water. In addition, the sea-water with different quantities of NaCl is used as a leachant to evaluate the effect of NaCl concentration. The IAEA test method (standard leaching test) and apparent dissolution model are applied to analyze the leaching characteristics. The representative radionuclides are Cs137,: Co60 and Sr90. According to this experimental results, the amounts of leached radionuclides in the sea-water is more than that in the distilled water for borate waste and resin waste forms

  5. The effect of V 2O 5 on alkaline earth zinc borate glasses studied by EPR and optical absorption

    Sumalatha, B.; Omkaram, I.; Rajavardhana Rao, T.; Linga Raju, Ch.

    2011-12-01

    10 wt% SrO:30 wt% ZnO:60 wt% B 2O 3 incorporated with different vanadyl concentrations were studied by means of electron paramagnetic resonance (EPR) and optical absorption techniques. The spin-Hamiltonian parameters ( g and A), bonding parameters ( α2 and β2∗2) and Fermi contact interaction parameter K have been calculated. The values of spin-Hamiltonian parameters indicate that the VO 2+ ions in strontium zinc borate glasses were present in octahedral sites with tetragonal compression. The spin concentration ( N) participating in resonance was calculated as a function of temperature (93-273 K) for strontium zinc borate glass sample containing 0.9 wt% of VO 2+ ions and the activation energy ( Ea) was calculated. From the EPR data, the paramagnetic susceptibility ( χ) was calculated at various temperatures and the Curie constant ( C) was evaluated from the 1/ χ- T graph. The optical absorption spectra of VO 2+ ions in these glasses show two bands corresponding to the transitions 2B 2g → 2B 1g and 2B 2g → 2E g in the order of decreasing energy respectively. The optical band gap energies ( Eopt) and Urbach energy (Δ E) have been determined from their ultraviolet edges. The theoretical values of optical basicity ( Λth) of these glasses have also been evaluated.

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

    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.

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

    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 glasses Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.075, year: 2004

  8. On the factors influencing the stability of the borate complexes of ribose, arabinose, lyxose and xylose. A picture from DFT calculations

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

    Amsterdam, 2007. s. 296. [12th International Conference on the Applications of Density Functional Theory in Physics and Chemistry. 24.08.2007-30.08.2007, Amsterdam] R&D Projects: GA AV ČR(CZ) IAA400550701 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : aldopentose * borates * DFT Subject RIV: BO - Biophysics

  9. Hydrothermal synthesis and characterization of the first mixed alkali borate-nitrate K3Na[B6O9(OH)3]NO3

    The first mixed alkali borate-nitrate K3Na[B6O9(OH)3]NO3 was synthesized under hydrothermal conditions from Na2B4O7·10H2O and K2B4O7·4H2O using KNO3 as a nitrate source. The compound crystallizes in the space group Pnnm (no. 58) with the lattice parameters a=1320.8(3), b=910.7(2), and c=1232.5(3) pm (Z=4). Isolated Sechserrings formed by BO4 and BO3 groups are linked through hydrogen bridges to form a three-dimensional network. - Graphical abstract: The first mixed alkali borate-nitrate K3Na[B6O9(OH)3]NO3 was synthesized under hydrothermal conditions from Na2B4O7·10H2O and K2B4O7·4H2O using KNO3 as a nitrate source. - Highlights: • The first mixed alkali borate-nitrate K3Na[B6O9(OH)3]NO3 is reported. • Hydrothermal conditions (240 °C, 3d) were used for the synthesis of K3Na[B6O9(OH)3]NO3. • Borate Sechserrings are interconnected through hydrogen-bonding

  10. Effect of halides addition on the ligand field of chromium in alkali borate glasses

    Hassan, M.A., E-mail: moukhtar_hassan@yahoo.com

    2013-10-15

    Highlights: •The 10 KM–64.7 B{sub 2}O{sub 3}–25 Na{sub 2}O–0.3 Cr{sub 2}O{sub 3} (M = Cl, Br and I) glassy system was prepared by a quenching method. •Optical basicity, ligand field theory optical band gap energy, refractive index, ESR and IR were studied. •The electronegativity plays an important role in deforming the crystal field around the transition metal ions. •The crystal-field sites of KCl or KBr sample are very strong compared to the very weak one in the KI sample. -- Abstract: Borate oxide glass system of composition 10 KM–64.7 B{sub 2}O{sub 3}–25 Na{sub 2}O–0.3 Cr{sub 2}O{sub 3} (M = Cl, Br and I) was prepared by conventional melt quenching technique. The amorphous nature of the investigated glasses was checked by the X-ray diffraction (XRD) technique. The optical basicity of the system has been calculated, and was found to increase by going from KCl to KBr and to KI. Optical absorption spectra were recorded in the UV–visible range. Through a careful analysis of the data, the ligand field parameters (crystal field strength Dq, Racah parameters B and nephelauxetic functions h) and the optical parameters (optical band gap, Urbach tail band width, and refractive index) have been estimated. The obtained results reveal a strong correlation between that ligand field parameters and the type of halogen atom; the crystal-field strength of KCl or KBr samples are very pronounced but it is rather weak in the KI sample. Electron spin resonance (ESR) has been used to probe the valency of the Chromium ions. The resulting ESR parameters revealed that chromium ions are predominantly in the trivalent state with traces of hexavalent state. Using Infrared spectroscopy (IR) information on the boron structural units has been obtained. The N{sub 4} ratio increases by replacing the KCl by KBr or KI, and it was found that the tetrahedral coordination of Cr{sup +} ions becomes preferential in the host glasses with increasing the optical basicity.

  11. Utilizing the Trispyrazolyl Borate Ligand for the Mimicking of O2-Activating Mononuclear Nonheme Iron Enzymes.

    Sallmann, Madleen; Limberg, Christian

    2015-10-20

    Mononuclear, O2-activating nonheme iron enzymes are a fascinating class of metalloproteines, capable of realizing the most different reactions, ranging from C-H activation, via O atom transfer to C-C bond cleavage, in the course of O2 activation. They can lead us the way to achieve similar reactions with comparable efficiency and selectivity in chemical laboratories, which would be highly desirable aiming at accessing value-added products or to achieve degradation of unwanted compounds. Hence, these enyzmes motivate attempts to construct artificial low-molecular weight analogues, mimicking structural or functional characteristics. Such models can, for instance, provide insights about which of the features inherent to an active site are essential and guarantee the enzyme function, and from this kind of information the minimal requirements for a biomimetic or bioinspired complex that may be applied in catalysis can be derived. On the other hand, they can contribute to an understanding of the enzyme functioning. In order to create such replicates, it is important to faithfully mimic the surroundings of the iron centers in their active sites. Most of them feature two histidine residues and one carboxylate donor, while a few exhibit a deceptively simple (His)3Fe active site. For the simulation of these, the trispyrazolyl borate ligand (Tp) particularly offers itself, as the facial arrangement of three pyrazole donors is reminiscent of the three histidine-derived imidazole donors. The focus of this Account will be on bioinorganic/biomimetic research from our laboratory utilizing Tp ligands to develop molecular models for (i) two representatives of the (His)3Fe-enzyme family, namely, the cysteine dioxygenase (CDO) and acetyl acetone dioxygenase (Dke1), (ii) a related but less well-explored variant of the CDO-the 2-aminoethanethiol dioxygenase-as well as (iii) the 2-His-1-carboxylate representative 1-aminocyclopropane-1-carboxylic acid oxidase (ACCO). The CDO catalyzes the

  12. Investigation of luminescence and spectroscopic properties of Nd3+ions in cadmium alkali borate glasses

    Mohan, Shaweta; Thind, Kulwant Singh

    2016-07-01

    Neodymium doped cadmium alkali borate glasses having composition 20CdOsbnd 20R2Osbnd 59.5H3BO3sbnd 0.5Nd2O3; (R = Li, Na and K) were prepared by conventional melt-quenching technique. The amorphous nature of the glasses was confirmed by X-ray diffraction studies. The physical properties such as density, refractive index, molar volume, rare earth ion concentration etc. were determined. Optical absorption and fluorescence spectra were recorded. 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. These parameters were in turn used to predict the radiative properties such as the radiative transition probability (A), radiative lifetime (τR) and branching ratio (βR) for the fluorescent levels of Nd3+ ion in the present glass series. The lasing efficiency of the prepared glasses has been characterized by the spectroscopic quality factor (Ω4/Ω6), the value of which is in the range of 0.2-1.5, typical for Nd3+ in different laser hosts. The variation of Ω2 with the change in alkali oxide has been attributed to the changes in the asymmetry of the ligand field at the rare earth ion site. The shift of the hypersensitive bands, study of the oscillator strengths and the variation of the spectral profile of the transition 4I9/2 → 4F7/2 + 4S3/2 indicate a maximum covalency of Ndsbnd O bond for glass with potassium ions. From the fluorescence spectra, peak wavelength (λp), effective line widths (Δλeff) and stimulated emission cross-section (σp) have been obtained for the three transitions 4F3/2 → 4I9/2,4F3/2 → 4I11/2 and4F3/2 → 4I13/2 of Nd3+ ion. The relatively high values of σp obtained for Nd3+ in present glass system suggest that these materials can be considered as suitable candidates for laser applications. The glass with potassium ions shows the highest value of the stimulated emission cross-section.

  13. Synthesis, thermoluminescence and dosimetric properties of La-doped zinc borates

    Kucuk, Nil, E-mail: nilkoc@uludag.edu.tr [Physics Department, Faculty of Arts and Sciences, Uludag University, Gorukle Campus, 16059 Bursa (Turkey); Kucuk, Ilker; Cakir, Merve [Physics Department, Faculty of Arts and Sciences, Uludag University, Gorukle Campus, 16059 Bursa (Turkey); Kaya Keles, Sule [Institute of Nuclear Science, Ankara University, Tandogan Campus, 06550 Ankara (Turkey)

    2013-07-15

    Dependence on the dose of beta radiation of undoped and La-doped ZnB{sub 2}O{sub 4} powder samples at 1%, 2%, 3%, 4%, 5% and 10% (by weight) was investigated by thermoluminescence technique. Powder samples were synthesized by the nitric acid method using the starting oxides [zinc oxide (ZnO), boric acid (H{sub 3}BO{sub 3}) and doped element oxide (La{sub 2}O{sub 3})]. The samples were characterized by X-ray diffraction (XRD). The thermoluminescence (TL) properties of the powder samples were measured with Risø TL/OSL DA-20 reader. TL glow curves were obtained with heating at a constant heating rate of 5 °C/s up to 450 °C. The dose response curves of the powder samples exposed to {sup 90}Sr beta radiation (40 mCi) were obtained in the dose range from 143 mGy to 60 Gy. Dose responses and minimum detectable dose (MDD) values for increasing radiation doses of the powder samples were determined. The dose responses of all the samples have shown a quite linear response to beta radiation. MDD value of 10% La-doped ZnB{sub 2}O{sub 4} powder sample which shows a high temperature peak at 207 °C was determined as 4 mGy. MDD values for 1%, 2%, 3%, 4% and 5% La-doped ZnB{sub 2}O{sub 4} powder samples were also determined as 10 mGy, 50 mGy, 10 mGy, 10 mGy and 30 mGy, respectively. Luminescence intensities of the powder samples were shown to be likely to be used for low radiation doses. Highlights: ► Powder samples of undoped and La-doped zinc borate were prepared by the nitric acid method. ► TL properties and dependence on the dose of beta radiation of the samples have been investigated. ► The dose responses of the powder samples showed good linearity. ► The results showed that ZnB{sub 2}O{sub 4}:La sample can be a promising TLD material for dosimetric applications.

  14. Synthesis, thermoluminescence and dosimetric properties of La-doped zinc borates

    Dependence on the dose of beta radiation of undoped and La-doped ZnB2O4 powder samples at 1%, 2%, 3%, 4%, 5% and 10% (by weight) was investigated by thermoluminescence technique. Powder samples were synthesized by the nitric acid method using the starting oxides [zinc oxide (ZnO), boric acid (H3BO3) and doped element oxide (La2O3)]. The samples were characterized by X-ray diffraction (XRD). The thermoluminescence (TL) properties of the powder samples were measured with Risø TL/OSL DA-20 reader. TL glow curves were obtained with heating at a constant heating rate of 5 °C/s up to 450 °C. The dose response curves of the powder samples exposed to 90Sr beta radiation (40 mCi) were obtained in the dose range from 143 mGy to 60 Gy. Dose responses and minimum detectable dose (MDD) values for increasing radiation doses of the powder samples were determined. The dose responses of all the samples have shown a quite linear response to beta radiation. MDD value of 10% La-doped ZnB2O4 powder sample which shows a high temperature peak at 207 °C was determined as 4 mGy. MDD values for 1%, 2%, 3%, 4% and 5% La-doped ZnB2O4 powder samples were also determined as 10 mGy, 50 mGy, 10 mGy, 10 mGy and 30 mGy, respectively. Luminescence intensities of the powder samples were shown to be likely to be used for low radiation doses. Highlights: ► Powder samples of undoped and La-doped zinc borate were prepared by the nitric acid method. ► TL properties and dependence on the dose of beta radiation of the samples have been investigated. ► The dose responses of the powder samples showed good linearity. ► The results showed that ZnB2O4:La sample can be a promising TLD material for dosimetric applications

  15. Tb{sup 3+} doped Zinc Alumino Bismuth Borate glasses for green emitting luminescent devices

    Swapna, K.; Mahamuda, Sk. [Department of Physics, K L University, Green Fields, Vaddeswaram, Guntur (Dt), Andhra Pradesh 522502 (India); Rao, A. Srinivasa, E-mail: drsrallam@gmail.com [Department of Physics, K L University, Green Fields, Vaddeswaram, Guntur (Dt), Andhra Pradesh 522502 (India); Department of Applied Physics, Delhi Technological University, Bawana Road, New Delhi 110042 (India); Jayasimhadri, M. [Department of Applied Physics, Delhi Technological University, Bawana Road, New Delhi 110042 (India); Shakya, Suman; Prakash, G. Vijaya [Nanophotonics Laboratory, Department of Physics, Indian Institute of Technology-Delhi, Hauz Khas, New Delhi 110016 (India)

    2014-12-15

    Zinc Alumino Bismuth Borate (ZnAlBiB) glasses doped with terbium (Tb{sup 3+}) ions with a chemical composition 20ZnO–10Al{sub 2}O{sub 3}–(10−x)Bi{sub 2}O{sub 3}–60B{sub 2}O{sub 3}−xTb{sub 2}O{sub 3} (x=0.1, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 mol%) were prepared by a conventional melt quenching method and studied their optical absorption, photoluminescence and decay spectral properties. The Judd–Ofelt (J–O) parameters evaluated from the experimental oscillator strengths were used to measure the radiative properties for the prominent luminescent transitions of Tb{sup 3+} ions such as {sup 5}D{sub 4}→{sup 7}F{sub 6}, {sup 7}F{sub 5}, {sup 7}F{sub 4} and {sup 7}F{sub 3.} The effect of Tb{sup 3+} ion concentration on the luminescence process observed in the visible region was discussed in detail. The emission spectra recorded for all the ZnAlBiB glasses doped with Tb{sup 3+} ions, show an intense peak in green region at 542 nm. The stimulated emission cross-section, branching ratios and quantum efficiency values evaluated for green emission ({sup 5}D{sub 4}→{sup 7}F{sub 5}) suggests the utility of these glasses for green luminescence applications. It was found that, within the concentration range investigated, 2.5 mol% of Tb{sup 3+} doped ZnAlBiB glass is most suitable for green luminescence applications at 542 nm in principle. - Highlights: • ZnAlBiB glasses doped with Tb{sup 3+} ions were prepared by a conventional melt quenching technique. • Judd–Ofelt and radiative properties are measured from the emission spectra. • Quantum efficiency of the ZnAlBiB glasses is measured by using radiative and measured lifetimes. • CIE Chromaticity co-ordinates are evaluated from emission spectra.

  16. Structural, absorption and fluorescence spectral analysis of Pr3+ ions doped zinc bismuth borate glasses

    Highlights: → 20ZnO.xBi2O3.(79.5-x)B2O3.0.5Pr6O11 (15 ≤ x ≤ 35) glasses were prepared by melt quench technique. → The Judd-Ofelt parameters Ωλ (λ = 2, 4, 6) and other radiative properties like radiative transition probability, radiative life time, branching ratio and stimulated emission cross-section of the prepared glasses have been calculated. → The branching ratio for 3P0 → 3F2 transition of Pr3+ doped glasses is 42% and the predicted spontaneous radiative transition probability rates are fairly high. - Abstract: Glasses having composition 20ZnO.xBi2O3.(79.5 - x)B2O3.0.5Pr6O11 were prepared by melt quench technique. The amorphous nature of the prepared glass samples was confirmed by X-ray diffraction. The spectroscopic properties of these glasses were investigated by recording optical absorption and fluorescence spectra. The structural investigations of the glasses were carried out by recording the IR spectra. The optical properties of Pr3+ ions doped zinc borate glasses with varying concentration of bismuth oxide have been studied. The Judd-Ofelt intensity parameters Ωλ (λ = 2, 4, 6) and other radiative properties like radiative transition probability, radiative life time, branching ratio and stimulated emission cross-section of the prepared glasses have been calculated. The variation of Ω2 with Bi2O3 content has been attributed to changes in the asymmetry of the ligand field at the rare earth ion site and to the changes in their rare earth oxygen (RE-O) covalency. The branching ratio for 3P0 → 3F2 transition is 42% and the predicted spontaneous radiative transition probability rates are fairly high (14,347-14,607 s-1). This is beneficial for lasing emission. The stimulated emission cross-section for all the emission bands has been calculated.

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

    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). PMID:24245313

  18. Structure and optical properties of a noncentrosymmetric borate RbSr{sub 4}(BO{sub 3}){sub 3}

    Xia, M.J. [Beijing Center for Crystal Research and Development, Key Laboratory of Functional Crystals and Laser Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Li, R.K., E-mail: rkli@mail.ipc.ac.cn [Beijing Center for Crystal Research and Development, Key Laboratory of Functional Crystals and Laser Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

    2013-01-15

    A new noncentrosymmetric borate, RbSr{sub 4}(BO{sub 3}){sub 3} (abbreviated as RSBO), has been grown from Rb{sub 2}O--B{sub 2}O{sub 3}--RbF flux and its crystal structure was determined by single crystal x-ray diffraction. It crystallizes in space group Ama2 with cell parameters of a=11.128(10) A, b=12.155(15) A, c=6.952(7) A, Z=4. The basic structural units are isolated planar BO{sub 3} groups. Second harmonic generation (SHG) test of the title compound by the Kurtz-Perry method shows that RSBO can be phase matchable with an effective SHG coefficient about two-thirds as large as that of KH{sub 2}PO{sub 4} (KDP). Finally, based on the anionic group approximation, the optical properties of the title compound are compared with those of the structure-related apatite-like compounds with the formula 'A{sub 5}(TO{sub n}){sub 3}X'. - Graphical abstract: RbSr{sub 4}(BO{sub 3}){sub 3} and some other borate NLO compounds, namely Ca{sub 5}(BO{sub 3}){sub 3}F RCa{sub 4}(BO{sub 3}){sub 3}O (R=Y or Gd) and Na{sub 3}La{sub 2}(BO{sub 3}){sub 3} can be viewed as the derivatives of apatite. They have similar formula composed of five cations and three anion groups (we call them 5/3 structures). The detailed SHG coefficients and optical properties of the apatite-like NLO crystals were compared and summarized. Highlights: Black-Right-Pointing-Pointer A new noncentrosymmetric borate RbSr{sub 4}(BO{sub 3}){sub 3} was grown from flux. Black-Right-Pointing-Pointer The RbSr{sub 4}(BO{sub 3}){sub 3} can be viewed as a derivative of the apatite-like structure. Black-Right-Pointing-Pointer The structure and its relationship to the optical properties of RbSr{sub 4}(BO{sub 3}){sub 3} are compared with other NLO crystals with apatite-like structures. Black-Right-Pointing-Pointer The basic structural units are the planar BO{sub 3} groups in the structure. Black-Right-Pointing-Pointer Second harmonic generation (SHG) test shows that RbSr{sub 4}(BO{sub 3}){sub 3} can be phase matchable

  19. 硼酸锌的阻燃机理及其纳米化制备研究进展%Inflaming Retarding Mechanism and Preparation Methods of Zinc Borate Nanoparticles

    袁光辉

    2011-01-01

    硼酸锌作为一种环保无机阻燃剂,具有无毒、无污染、阻燃及抑烟的优良性能。综述了硼酸锌阻燃剂的主要性质、阻燃机理和纳米硼酸锌的制备方法,指出硼酸锌的纳米化制备是目前合成工艺的研究重点。%Zinc borate is an inorganic flare retardant with environmental protection function. Its characteristics are good-stabillty, low-toxicity and no-smoke. This article summarizes the main property, the inflaming retarding mechanism of zinc borate and the preparing processes of zinc borate nanoparticles. The preparation of zinc borate nanoparticles is the emphasis of current research.

  20. Pb2 BO3 Cl: A Tailor-Made Polar Lead Borate Chloride with Very Strong Second Harmonic Generation.

    Zou, Guohong; Lin, Chensheng; Jo, Hongil; Nam, Gnu; You, Tae-Soo; Ok, Kang Min

    2016-09-19

    A meticulously designed, polar, non-centrosymmetric lead borate chloride, Pb2 BO3 Cl, was synthesized using KBe2 BO3 F2 (KBBF) as a model. Single-crystal X-ray diffraction revealed that the structure of Pb2 BO3 Cl consists of cationic [Pb2 (BO3 )](+) honeycomb layers and Cl(-) anions. Powder second harmonic generation (SHG) measurements on graded polycrystalline Pb2 BO3 Cl indicated that the title compound is phase-matchable (type I) and exhibits a remarkably strong SHG response, which is approximately nine times stronger than that of potassium dihydrogen phosphate, and the largest efficiency observed in materials with structures similar to KBBF. Further characterization suggested that the compound melts congruently at high temperature and has a wide transparency window from the near-UV to the mid-IR region. PMID:27555114

  1. Synthesis and photoluminescence properties of Pb2+ doped inorganic borate phosphor NaSr4(BO3)3

    Chauhan, A. O.; Koparkar, K. A.; Bajaj, N. S.; Omanwar, S. K.

    2016-05-01

    A series of Inorganic borate phosphors NaSr4(BO3)3 doped with Pb2+ 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 Pb2+ concentration for the NaSr4(BO3)3 were studied in details. The concentration quenching of Pb2+ doped NaSr4(BO3)3 was observed at 0.02 mol. The Stokes shifts of NaSr4(BO3)3: Pb2+ phosphor was calculated to be 7574 cm-1.

  2. Beam patterns in an optical parametric oscillator set-up employing walk-off compensating beta barium borate crystals

    This paper describes the investigation of an optical parametric oscillator (OPO) set-up based on two beta barium borate (BBO) crystals, where the interplay between the crystal orientations, cut angles and air dispersion substantially influenced the OPO performance, and especially the angular spectrum of the output beam. Theory suggests that if two BBO crystals are used in this type of design, they should be of different cuts. This paper aims to provide an experimental manifestation of this fact. Furthermore, it has been shown that air dispersion produces similar effects and should be taken into account. An x-ray crystallographic indexing of the crystals was performed as an independent test of the above conclusions. (paper)

  3. Borate fusion followed by ion-exchange/extraction chromatography for the rapid determination of Pu and U in environmental materials

    A method for actinide determinations has been established which has considerable advantages over currently described procedures. The benefits are rapid sample throughput, good safety features with no compromise in data quality. A borate fusion is used for the sample digestion. Chemical separation is optimized by using a column of anion-exchange resin column stacked on a UTEVA column. Uranium was measured using thermal ionization mass spectrometry with a precision of 0.2% 2 sigma. Pu measurements were made using alpha-particle spectrometry. The procedure has been applied successfully to a wide range of sample types and other actinide elements (Th, Am, etc.) could also be included in the analytical scheme. The method has been thoroughly evaluated by measuring international reference samples. The method lends itself very well to large-scale environmental surveys

  4. One-photon band gap engineering of borate glass doped with ZnO for photonics applications

    Abdel-Baki, Manal [Glass Department, National Research Centre, Dokki 12311 Giza (Egypt); Abdel-Wahab, Fathy A.; El-Diasty, Fouad [Physics Department, Faculty of Science, Ain Shams University, Abbasia, 11566 Cairo (Egypt)

    2012-04-01

    Lithium tungsten borate glass of the composition (0.56-x)B{sub 2}O{sub 3}-0.4Li{sub 2}O-xZnO-0.04WO{sub 3} (0 {<=}x{<=} 0.1 mol. %) is prepared for photonics applications. The glass is doped with ZnO to tune the glass absorption characteristics in a wide spectrum range (200-2500 nm). Chemical bond approach, including chemical structure, electronegativity, bond ionicity, nearest-neighbor coordination, and other chemical bonding aspect, is used to analyze and to explain the obtained glass properties such as: transmittance, absorption, electronic structure parameters (bandgap, Fermi level, and Urbach exciton-phonon coupling), Wannier free excitons excitation (applying Elliott's model), and two-photon absorption coefficient as a result of replacement of B{sub 2}O{sub 3} by ZnO.

  5. Gd4(BO2)O5F. A gadolinium borate fluoride oxide comprising a linear BO2 moiety

    Gadolinium borate fluoride oxide Gd4(BO2)O5F crystallises in space group Pmmm (No. 59, a = 1574.6(4), b = 381.42(7), c = 660.88(11) pm, 565 refl., 28 parameters, R1 = 0.039, wR2 = 0.128, twin refinement) and comprises linear BO2- anions between closely packed [GdO] layers formed by OGd4 tetrahedra and terminated by oxygen and fluorine atoms. The crystal structure's relationship with the NiAs type is illustrated. The Raman spectrum recorded on a single crystal of Gd4(BO2)O5F comprises a single peak at 1364 cm-1 assigned to the only Raman-active vibrational mode νs of the linear triatomic O-B-O units besides very weak peaks at 805 and 2084 cm-1 (presumably the respective δ and νas modes).

  6. Non-resonant magnetic X-ray scattering on rare-earth iron borates RFe3(BO3)4

    Non-resonant magnetic XRD (NRMXRD) experiments with photon energy of 100 keV where performed on selected compounds of the RFe3(BO3)4 family as a function of temperature and applied magnetic field. The results show the existence of several unexpected diffraction features, in particular the presence of a magnetic super-lattice peak, and the appearance of two reflections that violate the diffraction conditions for the low temperature phase P3121 of the iron borates. The magnetic nature of the former is concluded from analysing the scattering cross section at high energies and the magnetic structure of the different compounds. It is shown that the magnetic reflection reveals the magnetic properties of the material. For GdFe3(BO3)4, values for the component of the spin moment perpendicular to the scattering plane (S perpendicularto) have been determined as well as the angle between the spin moment and the hexagonal basal plane.

  7. Beam patterns in an optical parametric oscillator set-up employing walk-off compensating beta barium borate crystals

    Kaucikas, M.; Warren, M.; Michailovas, A.; Antanavicius, R.; van Thor, J. J.

    2013-02-01

    This paper describes the investigation of an optical parametric oscillator (OPO) set-up based on two beta barium borate (BBO) crystals, where the interplay between the crystal orientations, cut angles and air dispersion substantially influenced the OPO performance, and especially the angular spectrum of the output beam. Theory suggests that if two BBO crystals are used in this type of design, they should be of different cuts. This paper aims to provide an experimental manifestation of this fact. Furthermore, it has been shown that air dispersion produces similar effects and should be taken into account. An x-ray crystallographic indexing of the crystals was performed as an independent test of the above conclusions.

  8. Identification of ε-Fe2O3 nano-phase in borate glasses doped with Fe and Gd

    Ivanova, O. S.; Ivantsov, R. D.; Edelman, I. S.; Petrakovskaja, E. A.; Velikanov, D. A.; Zubavichus, Y. V.; Zaikovskii, V. I.; Stepanov, S. A.

    2016-03-01

    A new type of magnetic nanoparticles was revealed in borate glasses co-doped with low contents of iron and gadolinium. Structure and magnetic properties of the particles differ essentially from that of the α-Fe2O3, γ-Fe2O3, or Fe3O4 nanoparticles which were detected earlier in similar glass matrices. Transmission electron microscopy including STEM-HAADF and EDX, synchrotron radiation-based XRD, static magnetic measurements, magnetic circular dichroism, and electron magnetic resonance studies allow referring the nanoparticles to the iron oxide phase-ε-Fe2O3. Analysis of the data set has shown that it is Gd atoms that govern the process of nanoparticles' nucleation and its incorporation into the particles in different proportions can be used to adjust their magnetic and magneto-optical characteristics.

  9. Study of the response of a lithium yttrium borate scintillator based neutron rem counter by Monte Carlo radiation transport simulations

    Sunil, C.; Tyagi, Mohit; Biju, K.; Shanbhag, A. A.; Bandyopadhyay, T.

    2015-12-01

    The scarcity and the high cost of 3He has spurred the use of various detectors for neutron monitoring. A new lithium yttrium borate scintillator developed in BARC has been studied for its use in a neutron rem counter. The scintillator is made of natural lithium and boron, and the yield of reaction products that will generate a signal in a real time detector has been studied by FLUKA Monte Carlo radiation transport code. A 2 cm lead introduced to enhance the gamma rejection shows no appreciable change in the shape of the fluence response or in the yield of reaction products. The fluence response when normalized at the average energy of an Am-Be neutron source shows promise of being used as rem counter.

  10. Visible photon multiplication in Ce3+–Tb3+ doped borate glasses for enhanced solar cells

    Visible photon multiplication is exposed in the Ce3+–Tb3+ doped alkaline-earth borate (LKZBSB) glass system. Efficient green and blue fluorescences originate from Tb3+ and Ce3+ emitting centres, respectively. Evaluation of absolute spectral parameters reveals that the quantum yield of Tb3+ single doped LKZBSB glasses is ∼8% under UVA radiation. Furthermore, with the introduction of Ce3+ into the Tb3+ doping system, the effective excitation wavelength range and the emission intensity of Tb3+ in LKZBSB glasses are remarkably expanded and improved by a maximum sensitization factor of ∼52 in the UVB spectral region. These results demonstrate that the Ce3+–Tb3+ doped LKZBSB glass system has promising potential as an efficient UV → Visible radiation conversion layer for the enhancement of solar cell efficiency, including cells employed in outer space. (paper)

  11. 3-Methyl-4,5-di­hydro­oxazolium tetra­phenyl­borate

    Tiritiris, Ioannis; Saur, Stefan; Kantlehner, Willi

    2014-01-01

    In the cation of the title salt, C4H8NO+·C24H20B−, the C—N bond lengths are 1.272 (2), 1.4557 (19) and 1.4638 (19) Å, indicating double- and single-bond character, respectively. The C—O bond length of 1.3098 (19) Å shows that double-bond character and charge delocalization occurs within the NCO plane of the cation. In the crystal, a C—H⋯π inter­action is present between the methyl­ene H atom of the cation and one phenyl ring of the tetra­phenyl­borate ion. The latter forms an aromatic pocket in which the cation is embedded. PMID:24765023

  12. Thermally stimulated luminescence and lattice defects in crystals of alkali metal borate LiB3O5 (LBO)

    The recombination processes and lattice defects in crystals of alkali metal borate LiB3O5 (LBO) were studied by the means of the thermally stimulated luminescence (TL) and electron spin resonance (ESR) techniques. The glow curves, the spectra of the LBO recombination luminescence, and the angular variations of ESR-spectra of the O- center in three different planes were measured in the temperature range from 80 to 400 K. The luminescence bands were assigned to the electron (Em=4.0 eV) and hole (Em=4.2 eV) recombination processes. The model of the trapped hole center O- was proposed. The processes responsible for the formation of localised electronic excitations in LBO were discussed and compared with those taking place in other wide-gap oxides

  13. STUDIES OF A.C. CONDUCTIVITY OF POLY(VINYL BORATE) AND ITS CALCIUM DERIVATIVE IN SOLID STATE

    Prafulla Chetri; Neelotpal Sen Sarma; Narendra Nath Dass

    2008-01-01

    An attempt has been made in the present work to prepare poly(vinyl borate), PVBO and its calcium derivative by homogeneous esterification of PVA with boric acid in non-aqueous medium in the presence of a catalyst ethyl nitrate dimethyl sulfoxide. The compounds were characterized by IR and 1H-NMR spectra. Conductivities were determined from 30℃ to 90℃ in solid state within a frequency range of 42 Hz to 100 kHz. The compounds so formed showed ionic conductivity and their conductivities were dependent on frequencies used. It is found that the addition of Ca2+ ion increases the ionic conductivity of PVBO appreciably. The conductivity of PVBO-Ca increases rapidly after 50℃. The total ionic transport number and activation energy of the copolymers were also determined.

  14. One-photon band gap engineering of borate glass doped with ZnO for photonics applications

    Lithium tungsten borate glass of the composition (0.56-x)B2O3-0.4Li2O-xZnO-0.04WO3 (0 ≤x≤ 0.1 mol. %) is prepared for photonics applications. The glass is doped with ZnO to tune the glass absorption characteristics in a wide spectrum range (200-2500 nm). Chemical bond approach, including chemical structure, electronegativity, bond ionicity, nearest-neighbor coordination, and other chemical bonding aspect, is used to analyze and to explain the obtained glass properties such as: transmittance, absorption, electronic structure parameters (bandgap, Fermi level, and Urbach exciton-phonon coupling), Wannier free excitons excitation (applying Elliott's model), and two-photon absorption coefficient as a result of replacement of B2O3 by ZnO.

  15. Effect of Co(2+) and Ni(2+)-doped zinc borate nano crystalline powders by co-precipitation method.

    Shim, Jaesool; Venkata Reddy, Ch; Sarma, G V S S; Narayana Murthy, P; Ravikumar, R V S S N

    2015-05-01

    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. PMID:25706597

  16. Effect of Co2+ and Ni2+-doped zinc borate nano crystalline powders by co-precipitation method

    Shim, Jaesool; Venkata Reddy, Ch.; Sarma, G. V. S. S.; Narayana Murthy, P.; Ravikumar, R. V. S. S. N.

    2015-05-01

    A simple co-precipitation method has been used for the synthesis of Co2+ and Ni2+-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.

  17. Photoannealing of radiation induced colour centers in sodium borate glasses with group 2B-5B metal oxides

    Using the methods of microsecond pulse radiolysis (PR), optical and ESR-spectroscopy, the processes of photoannealing of radiation induced colour centres (RICC) on the basis of metal ions in unstable oxidation states (MIUOS) in 2S1/2 electron state in sodium-borate glasses (SBG) in a wide time range have been investigated. Absorption spectra of the RICC are determined. It is shown that the effectiveness of RICC destruction depends both on the intensity and spectral composition of the affecting light. It is ascertained that the energy of optical transitions in the maxima of absorption bands (AB) and effectiveness of MIUOS destruction with an increase in the oxidation degree of ions Z decrease regularly in isoelectron series

  18. Photoannealing of radiation color centers in sodium borate glasses with oxides of metals from groups IIB-VB

    The processes resulting in the photoannealing of radiation color centers based on ions of metals in unstable oxidation states in the 2S1/2 electronic state in sodium borate glasses have been investigated by microsecond pulse radiolysis, optical spectroscopy, and ESR spectroscopy over a broad range of times. The absorption spectra of these radiation color centers have been determined. It has been shown that the efficiency of the destruction of the radiation color centers depends both on the intensity and on the spectroscopic composition of the light used. It has been established that the energy of the optical transitions at the maxima of the absorption bands and the efficiency of the destruction of the metal ions in unstable oxidation states undergo regular decreases along isoelectronic series as the oxidation number of the ions Z is increased

  19. Luminescence properties of Dy3+ ions in a variety of borate and fluoroborate glasses containing lithium, zinc, and lead

    The fluorescence properties of Dy3+ ions, with two concentrations (1.0 and 0.1 mol%), have been investigated in a variety of borate and fluoroborate glasses modified with lithium, zinc, and/or lead. The fluorescence spectra and lifetimes of 4F9/2 level of Dy3+ ions in these glasses have been measured using the 457.9 nm line of argon ion laser as an excitation source. Decreasing trend in lifetimes has been observed when the glass compositions contain modifiers in the order of LiF→Li2O→ZnO→PbO. Decay curves for these glasses are found to be single exponential and non-exponential for 0.1 and 1.0 mol% concentrations, respectively. The non-exponential decay curves have been well fitted with the Inokuti-Hirayama (I-H) model for dipole-dipole interaction

  20. Synthesis and spectral analysis of Sm:BaB4O7 microfibers embedded in borate glass

    The present article reports synthesis and spectroscopic analysis of Sm:BaB4O7 microfibers embedded in borate glass. Structural analysis, using TEM, XRD techniques, revealed the formation of fibre shaped BaB4O7 crystals. A bright red dominated orange–red emission was observed, on 355 nm and 532 nm excitations, in ceramic sample. Higher emission and absorption higher cross-sections were observed in the ceramic sample than its glass counterpart. We have monitored 45% enhancement in emission intensity ratio (4G5/2→6H9/2/G5/2→6H5/2) in glass–ceramic sample due to significant increment in electric dipole transition. Time resolved analysis explored a significant alteration in the excited state relaxation process due to annealing. Several radiative parameters like stimulated emission cross-section, branching ratio, quantum efficiency etc. were estimated to explore lasing possibility in glass and ceramic samples. We found that the quantum efficiency increases from 60.4% in glass to 62.7% in Sm:BaB4O7 microfibers embedded in glass. - Highlights: • Synthesis of fibre shaped surface crystallized Sm:BaB4O7 reported in borate glass. • Strong red PL reported at various physical conditions on 532 and 355 nm excitations. • Effect of fibre growth on absorption, PL, decay dynamics was investigated. • J–O model used to calculate branching ratio, radiative lifetime, quantum efficiency. • Stimulated emission cross-section, bandwidth, gain enhances several times in fibres