The American Ceramic Society 44Th International Conference
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LIGHT METAL BOROHYDRIDES and Mg-BASED HYDRIDES for HYDROGEN STORAGE
LIGHT METAL BOROHYDRIDES AND Mg-BASED HYDRIDES FOR HYDROGEN STORAGE by SHENG GUO A thesis submitted to the University of Birmingham for the degree of DOCTOR OF PHILOSOPHY School of Metallurgy and Materials College of Engineering and Physical Sciences University of Birmingham December 2014 University of Birmingham Research Archive e-theses repository This unpublished thesis/dissertation is copyright of the author and/or third parties. The intellectual property rights of the author or third parties in respect of this work are as defined by The Copyright Designs and Patents Act 1988 or as modified by any successor legislation. Any use made of information contained in this thesis/dissertation must be in accordance with that legislation and must be properly acknowledged. Further distribution or reproduction in any format is prohibited without the permission of the copyright holder. Synopsis This work has investigated structural and compositional changes in LiBH4, Mg(BH4)2, Ca(BH4)2, LiBH4-Ca(BH4)2 during heating. The crystal and vibrational structures of these borohydrides/composites were characterized using lab-based X-ray diffraction (XRD) and Raman spectroscopy, with particular attention to the frequency/width changes of Raman vibrations of different polymorphs of borohydrides. The thermal stability and decomposition pathway of the borohydrides was studied in great detail mainly using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), in/ex situ XRD and Raman measurements, whilst the gaseous products during heating were monitored using a mass spectrometry (MS). Hydrogen is the main decomposition gaseous product from all of these compounds, but in some cases a very small amount of diborane release was also detected. -
Superhard and Superconducting B6C
Superhard and Superconducting B6C Kang Xia a, Mengdong Ma b, Cong Liu a, Hao Gao a, Qun Chen a, Julong He b, Jian Sun a,*, Hui-Tian Wang a, Yongjun Tian b, and Dingyu Xing a a National Laboratory of Solid State Microstructures, School of Physics and Collaborative Innovation Center of Advanced Microstructure, Nanjing University, Nanjing 210093, China b State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China ABSTRACT Crystal structure searching and ab initio calculations have been used here to explore low-energy structures of boron carbides under high pressure. Under pressures of 85–110 GPa, a metastable B6C with R3 m symmetry is found to be energetically more stable than the mixture of previous B4C and elemental boron. This B6C is a rhombohedral structure and contains mooncake-like B24 clusters with stuffing of C2 pairs. The mechanical and dynamical stabilities of this structure at ambient pressure are confirmed by its elastic constants and phonon dispersions. The bulk modulus and shear modulus of this newly predicted B6C at ambient pressure reach high values of 291 GPa and 272 GPa, respectively. The Vickers hardness is calculated to be around 48 GPa, and its melting temperature at ambient pressure is estimated to be around 2500 K, indicating that this metastable B6C is a potential superhard material with very good thermal stability. Interestingly, this superhard B6C structure is also found to be superconducting and its superconducting critical temperature (Tc) is evaluated to be around 12.5 K at ambient pressure by electron-phonon coupling. * Corresponding author. E-mail address: [email protected] 1. -
NNL TSL Evaluations for Yttrium Hydride and Hexagonal Ice
NNL TSL Evaluations for Yttrium Hydride and Hexagonal Ice Michael Zerkle and Jesse Holmes Naval Nuclear Laboratory Cross Section Evaluation Working Group Meeting November 14-16, 2016 Brookhaven National Laboratory The Naval Nuclear Laboratory is operated for the U.S. Department of Energy and the U.S. Department of the Navy by Bechtel Marine Propulsion Corporation, a wholly owned subsidiary of Bechtel National, Inc. NNL TSL Evaluations Material MAT H(YH2) 5 Y(YH2) 55 H(ice-Ih) 10 O(ice-Ih) 50 2 YH2 Background • Yttrium hydride (YH2) is an advanced high temperature moderator • Superior hydrogen density (NH) at elevated temperatures • Keinert (1971) proposed H(YH2) TSL based on simple analytic frequency distributions • Debye-type for acoustic mode • Gaussian-type for optical mode • Higher-fidelity TSLs for H(YH2) and Y(YH2) developed using first- principles calculations • Density Functional Theory (DFT) to calculate interatomic Hellman- Feynman forces for crystal structure Hydrogen in metallic Zr, Ce, Y and Ca in equilibrium with 1 atm H at various temperatures. • Lattice Dynamics (LD) to determine 2 dispersion relations and phonon (Source: Metal Hydrides, Academic Press, p. 442, 1968) density of states (DOS) -22 NH is number of hydrogen atoms/cc x 10 3 Ab Initio Calculation of Phonon Spectra 4 YH2 Structure and Lattice Dynamics • YH2 has a CaF2 type FCC structure • 12 atoms • 4 Y atoms (blue) at vertices and faces of unit cell • 8 H atoms (grey) in tetrahedral holes between Y atoms • Dispersion relations (at right) • Well separated acoustical and optical modes • Lower branches are acoustical modes mainly due to heavy Y atom vibrations • Higher branches are optical modes mainly due to light H atom vibrations 5 YH2 Phonon Density of States 6 YH2 Phonon Density of States High resolution inelastic neutron scattering spectra from Udovic shows similar structure for YH2 centered on 0.127 eV. -
NETS 2020 Template
بÀƵƧǘȁǞƧƊǶ §ȲȌǐȲƊǿ ƊƧDzɈȌɈǘƵwȌȌȁƊȁƮȌȁ ɈȌwƊȲȺɈǘȲȌɐǐǘƊƮɨƊȁƧǞȁǐ خȁɐƧǶƵƊȲɈƵƧǘȁȌǶȌǐǞƵȺƊȁƮ ǞȁȁȌɨƊɈǞȌȁ ǞȺ ȺȯȌȁȺȌȲƵƮ Ʀɯ ɈǘƵ ƊDz ªǞƮǐƵ yƊɈǞȌȁƊǶ ׁׂ׀ׂ y0À² ÀǘǞȺ ƧȌȁǏƵȲƵȁƧƵ خׁׂ׀ׂ ةɈǘ׀׃ƊȁƮ ɩǞǶǶƦƵ ǘƵǶƮ ǏȲȌǿȯȲǞǶ ׂ׆ɈǘٌةmƊƦȌȲƊɈȌȲɯ ɩǞǶǶ ƦƵ ǘƵǶƮ ɨǞȲɈɐƊǶǶɯ ȺȌ ɈǘƊɈ ɈǘƵ ƵȁɈǞȲƵ y0À² خƧȌǿǿɐȁǞɈɯǿƊɯȯƊȲɈǞƧǞȯƊɈƵǞȁɈǘǞȺƵɮƧǞɈǞȁǐǿƵƵɈǞȁǐ ǐȌɨخȌȲȁǶخخׁׂ׀ȁƵɈȺׂششبǘɈɈȯȺ Nuclear and Emerging Technologies for Space Sponsored by Oak Ridge National Laboratory, April 26th-30th, 2021. Available online at https://nets2021.ornl.gov Table of Contents Table of Contents .................................................................................................................................................... 1 Thanks to the NETS2021 Sponsors! ...................................................................................................................... 2 Nuclear and Emerging Technologies for Space 2021 – Schedule at a Glance ................................................. 3 Nuclear and Emerging Technologies for Space 2021 – Technical Sessions and Panels By Track ............... 6 Nuclear and Emerging Technologies for Space 2021 – Lightning Talk Final Program ................................... 8 Nuclear and Emerging Technologies for Space 2021 – Track 1 Final Program ............................................. 11 Nuclear and Emerging Technologies for Space 2021 – Track 2 Final Program ............................................. 14 Nuclear and Emerging Technologies for Space 2021 – Track 3 Final Program ............................................. 18 -
Volumetric Determination of Boron in Boron Carbide V
B. A. R. C.-1017 ei GOVERNMENT OF INDIA ATOMIC ENERGY COMMISSION VOLUMETRIC DETERMINATION OF BORON IN BORON CARBIDE V. K. Manchanda and M. S. Subramanian Radiochemistry Division BHABHA ATOMIC RESEARCH CENTRE BOMBAY, INDIA 1979 B. A. R.C.-1017 GOVERNMENT OF INDIA ATOMIC ENERGY COMMISSION U erf < ffl VOLUMETRIC DETERMINATION OF BORON IN BORON CARBIDE by V.K. Manchanda and M. S. Subramantan Radlochernlstry Division BHABHA ATOMIC RESEARCH CENTRE BOMBAY, INDIA 1979 INIS Subject Category : Bll Descriptor a : BORON CARBIDES BORON QUANTITATIVE CHEMICAL ANALYSIS TITRATION ACCURACY ABSTRACT Boron carbide is used for oontrol rods and as a shielding material In nuclear reactors. As such, the boron carbide must conform to rigid chemical specifications. Impurities present have a significant effect on the life time of the control rods under conditions of high temperature and i neutron flux. Therefore, methods for the accurate determination of the various constituents in boron carbide is of utmost importance. This-report discusses p\volumetric procedure for i •_ . •' i : ((.•>;•" ••%. the, determination of boron content In boron carbide/ '•••>',••. A VOLtCIKTRIC DET3SIINATI0N 0? BCRON IN BORON CAR3IDE by V.K. Jfenchanda and M.S. Subramanian IU7R0DVCT10N Boron carbide is an important nuclear material a.3 it is used in nuclear reactors for control rods and as a shielding material « Preparation of boron carbide yields a product often contaminated with either unreacted carbon or boric acid. These impurities affect the physical, chemical and neutron absorption properties of the material, Particularly under conditions of high temperature and neutron flux in a reactor, tlie life time of the control rods depends on its composition. -
Catalytic Systems Based on Cp2zrx2 (X = Cl, H), Organoaluminum
catalysts Article Catalytic Systems Based on Cp2ZrX2 (X = Cl, H), Organoaluminum Compounds and Perfluorophenylboranes: Role of Zr,Zr- and Zr,Al-Hydride Intermediates in Alkene Dimerization and Oligomerization Lyudmila V. Parfenova 1,* , Pavel V. Kovyazin 1, Almira Kh. Bikmeeva 1 and Eldar R. Palatov 2 1 Institute of Petrochemistry and Catalysis of Russian Academy of Sciences, Prospekt Oktyabrya, 141, 450075 Ufa, Russia; [email protected] (P.V.K.); [email protected] (A.K.B.) 2 Bashkir State University, st. Zaki Validi, 32, 450076 Ufa, Russia; [email protected] * Correspondence: [email protected]; Tel.: +7-347-284-3527 i i Abstract: The activity and chemoselectivity of the Cp2ZrCl2-XAlBu 2 (X = H, Bu ) and [Cp2ZrH2]2- ClAlEt2 catalytic systems activated by (Ph3C)[B(C6F5)4] or B(C6F5)3 were studied in reactions with 1-hexene. The activation of the systems by B(C6F5)3 resulted in the selective formation of head- to-tail alkene dimers in up to 93% yields. NMR studies of the reactions of Zr complexes with organoaluminum compounds (OACs) and boron activators showed the formation of Zr,Zr- and Zr,Al-hydride intermediates, for which diffusion coefficients, hydrodynamic radii, and volumes were estimated using the diffusion ordered spectroscopy DOSY. Bis-zirconium hydride clusters of type x[Cp ZrH ·Cp ZrHCl·ClAlR ]·yRnAl(C F ) − were found to be the key intermediates of alkene 2 2 2 2 6 5 3 n dimerization, whereas cationic Zr,Al-hydrides led to the formation of oligomers. Citation: Parfenova, L.V.; Kovyazin, P.V.; Bikmeeva, A.K.; Palatov, E.R. -
State of the Art in the Use of Bioceramics to Elaborate 3D
RESEARCH PAPER RESEARCH State of the art in the use of... INTERNATIONAL JOURNAL OF ADVANCES IN MEDICAL BIOTECHNOLOGY State of the art in the use of bioceramics to elaborate 3D structures using robocasting Juliana Kelmy Macário Barboza Daguano1,2*; Claudinei dos Santos3; Manuel Fellipe Rodrigues Pais Alves4; Jorge Vicente Lopes da Silva2; Marina Trevelin Souza5; Maria Helena Figueira Vaz Fernandes6 *Corresponding author: E-mail address:[email protected] Abstract: Robocasting, also known as Direct Ink Writing, is an Additive Manufacturing (AM) technique based on the direct extrusion of colloidal systems consisting of computer-controlled layer-by-layer deposition of a highly concentrated suspension (ceramic paste) through a nozzle into which this suspension is extruded. This paper presents an overview of the contributions and challenges in developing three-dimensional (3D) ceramic biomaterials by this printing method. State-of-art in different bioceramics as Alumina, Zirconia, Calcium Phosphates, Glass/Glass-ceramics, and composites is presented and discussed regarding their applications and biological behavior, in a survey comprising from the production of customized dental prosthesis to biofabricating 3D human tissues. Although robocasting represents a disruption in manufacturing porous structures, such as scaffolds for Tissue Engineering (TE), many drawbacks still remain to overcome and although widely disseminated this technique is far from allowing the obtainment of dense parts. Thus, strategies for manufacturing densified bioceramics are presented aiming at expanding the possibilities of this AM technique. The advantages and disadvantages and also future perspectives of applying robocasting in bioceramic processing are also explored. Keywords: Additive Manufacturing (AM); Direct Ink Writing (DIW); Robocasting; Bioceramics; Challenges; Perspectives. -
Synthesis, Reactivity, and Catalysis of Group 3 and Lanthanide Alkyl Complexes
Synthesis, Reactivity, and Catalysis of Group 3 and Lanthanide Alkyl Complexes By Daniel Steven Levine A dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Chemistry in the Graduate Division of the University of California, Berkeley Committee in charge: Professor T. Don Tilley, Co-Chair Professor Richard A. Andersen, Co-Chair Professor Alexis T. Bell Summer 2016 Abstract Synthesis, Reactivity, and Catalysis of Group 3 and Lanthanide Alkyl Complexes by Daniel Steven Levine Doctor of Philosophy in Chemistry University of California, Berkeley Professor T. Don Tilley, Co-Chair Professor Richard A. Andersen, Co-Chair Chapter 1. A series of scandium dialkyl complexes, (PNP)ScR2 (R = neopentyl, trimethylsilylmethyl), supported by the monoanionic, chelating PNP ligand (2,5- bis(dialkylphosphinomethyl)pyrrolide; alkyl = cyclohexyl, tert-butyl) was synthesized and the reactivities of these complexes toward simple hydrocarbons was investigated. The scandium– carbon bonds undergo σ-bond metathesis reactions with hydrogen and these complexes are catalysts for the hydrogenation of alkenes. Reactions with primary amines led to formation of amido complexes that undergo cyclometalation via σ-bond metathesis, without involvement of an imido complex intermediate. A variety of carbon-hydrogen bonds are also activated, including sp-, sp2-, and sp3-C–H bonds (intramolecularly in the latter case). Levine, D. S.; Tilley, T. D.; Andersen, R. A. Organometallics 2015, 34 (19), 4647. Chapter 2. Terminal group 3 methylidene complexes are generated by thermolysis of monoanionic PNP-supported scandium and yttrium dialkyl complexes. The reaction mechanism has been probed by deuterium-labeling experiments and DFT calculations. Abstraction of a γ- hydrogen from one alkyl group by the other affords a metallacyclobutane that undergoes [2+2] cycloreversion, analogous to a key step in the olefin metathesis reaction, to generate a methylidene complex and isobutene. -
The Corning Museum of Glass Annual Report, 2006
The Corning Museum of Glass Annual Report 2006 Cover: Officers The Fellows of The Corning The Fellows of The Corning Museum of Glass Museum of Glass are among Peacock vase, blown; E. Marie McKee the world’s leading glass col- silver-gilt mount. U.S., President Carole Allaire lectors, scholars, dealers, and Corona, NY, Tiffany Gary E. Baker glassmakers. The objectives Amory Houghton Jr. Studios, 1898–1899. Renée E. Belfer of this organization are (1) Vice President H. 14.1 cm (2006.4.161). Robert A. Belfer to disseminate knowledge James R. Houghton Mike Belkin about the history and art of Vice President William W. Boeschenstein* glassmaking and (2) to sup- port the acquisitions program Alan L. Cameros Denise A. Hauselt of the Museum’s Rakow Secretary Lt. Gen. Christian Clausen, retired Research Library. Admission Thomas P. Dimitroff to the fellowship is intended James B. Flaws Jay R. Doros to recognize accomplishment, Treasurer David Dowler and is by invitation. Robert J. Grassi Max Erlacher Assistant Treasurer Christopher T. G. Fish Barbara U. Giesicke David B. Whitehouse William Gudenrath Executive Director Jirˇí Harcuba+ Douglas Heller Trustees A. C. Hubbard Jr. Roger G. Ackerman* Kenneth L. Jobe + Peter S. Aldridge Dorothy-Lee Jones Thomas S. Buechner Leo Kaplan Van C. Campbell* Helena Koenigsmarková + Dale Chihuly Michael Kovacek Patricia T. Dann Dwight P. Lanmon + Robert Duke Harvey K. Littleton James B. Flaws Louise Luther John P. Fox Jr. Kenneth W. Lyon Polly W. Guth Josef Marcolin Ben W. Heineman* John H. Martin + Amory Houghton Jr.* Gregory A. Merkel Arthur A. Houghton III Barbara H. -
The Formation and Reactivity of I BORON CARBIDE and Related
University of Plymouth PEARL https://pearl.plymouth.ac.uk 04 University of Plymouth Research Theses 01 Research Theses Main Collection 1970 The Formation and Reactivity of BORON CARBIDE and related materials JONES, JAMES ALFRED http://hdl.handle.net/10026.1/1880 University of Plymouth All content in PEARL is protected by copyright law. Author manuscripts are made available in accordance with publisher policies. Please cite only the published version using the details provided on the item record or document. In the absence of an open licence (e.g. Creative Commons), permissions for further reuse of content should be sought from the publisher or author. The Formation and Reactivity of I BORON CARBIDE and related materials A Thesis presented for the Research Degree of DOCTOR OF PHILOSOPHY of the COUNCIL FOR NATIONAL ACADEMIC AWARDS London by JAMES ALFRED JONES Department of Chemistry Plymouth Polytechnic Plymouth, Devon- February^ 1970o F'.V flCCH. i'iC. 1 CLASS, T Shi LJl JoH 13' ABSTRACT 1 The formation of boron carbide, (CBC)*B^^0*^(3^0 is re• viewed with special reference to newer production methods and fabrication techniques. Its crystal structure and the nature of its bonding are discussed in relation to those of other borides and carbides. Information so far available on the sintering of this material is summarised in relation to its reactivity. Sintering into monolithic compoaentBcan only be achieved by hot pressing at pressures between 200 and 300 Kgcm'^ and at temperatures above 2000°C preferably at about 2,300^0 for the most rapid achievement of theoretical density, i.e. -
The 5-Th Element a New High Pressure High Temperature Allotrope
The 5-th element A new high pressure high temperature allotrope Von der Fakultät für Chemie und Geowissenschaften Der Universität Bayreuth zur Erlangung der Würde eines Doctors der Naturwissenschaften -Dr. rer. nat.- Dissertation vorgelegt von Evgeniya Zarechnaya aus Moskau (Russland) Bayreuth, April 2010 TABLE OF CONTENTS SUMMARY................................................................................................................................................... 1 ZUSAMMENFASSUNG.............................................................................................................................. 3 1 INTRODUCTION....................................................................................................................... 6 1.1 History of the discovery of boron................................................................................................... 6 1.2 Basic chemistry and crystal-chemistry of boron........................................................................... 7 1.3 Boron in natural systems ................................................................................................................ 9 1.4 Physical properties of boron and its application ........................................................................ 12 1.5 Boron at high pressure.................................................................................................................. 15 1.6 Experimental techniques and sample characterization ............................................................ -
Processing of Reaction-Bonded B4C–Sic Composites in a Single-Mode Microwave Cavity
Available online at www.sciencedirect.com CERAMICS INTERNATIONAL Ceramics International 39 (2013) 1215–1219 www.elsevier.com/locate/ceramint Processing of reaction-bonded B4C–SiC composites in a single-mode microwave cavity Anthony Thuaulta,n, Sylvain Marinela,b, Etienne Savarya,c, Romain Heugueta, Se´bastien Saunierc, Dominique Goeuriotc, Dinesh Agrawalb aCRISMAT Laboratory UMR 6508 CNRS-ENSICAEN-UCBN, 6 Boulevard du Mare´chal Juin, 14050 Caen Cedex, France bMaterials Research Institute, Materials Research Laboratory Building, The Pennsylvania State University, University Park, PA 16802, USA cDe´partement Me´canique et Proce´de´s d’e´laboration, Centre des Sciences des Mate´riaux et des Structures, Ecole Nationale Supe´rieure des Mines de Saint- Etienne, 42023 Saint-Etienne Cedex 2, France Received 5 July 2012; received in revised form 16 July 2012; accepted 16 July 2012 Available online 24 July 2012 Abstract In this study, the reaction sintering of boron carbide, which consists in doing reactive infiltration of molten silicon throughout a porous sample made of B4C and carbon graphite was investigated. Thus, it has been shown that a single-mode microwave cavity can be successfully used to produce reaction-bonded B4C–SiC composite. A specific package, consisting of a SiC based susceptor and a boron nitride based insulating container, was used to heat up the B4C–Si system using a single-mode microwaves cavity under an Ar–H2 atmosphere. Pore-free B4C–SiC composite successfully produced consists of a mixture of B4C and polygonal shaped b-SiC within a residual silicon matrix. The indentation technique permits to determine mechanical properties of the samples which are compared to those obtained conventionally.