NORTHWESTERN UNIVERSITY Understanding Atomic Structure
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.. & METEORITIC RUTILE Peter R. Buseck Departments of Geology and Chemistry Arizona State University Tempe, Arizona Klaus Keil Space Sciences Division National Aeronautics and Space Administration Ames Research Center Mof fett Field, California r ABSTRACT Rutile has not been widely recognized as a meteoritic constituent. show, Recent microscopic and electron microprobe studies however, that Ti02 . is a reasonably widespread phase, albeit in minor amounts. X-ray diffraction studies confirm the Ti02 to be rutile. It was observed in the following meteorites - Allegan, Bondoc, Estherville, Farmington, and Vaca Muerta, The rutile is associated primarily with ilmenite and chromite, in some cases as exsolution lamellae. Accepted for publication by American Mineralogist . Rutile, as a meteoritic phase, is not widely known. In their sunanary . of meteorite mineralogy neither Mason (1962) nor Ramdohr (1963) report rutile as a mineral occurring in meteorites, although Ramdohr did describe a similar phase from the Faxmington meteorite in his list of "unidentified minerals," He suggested (correctly) that his "mineral D" dght be rutile. He also ob- served it in several mesosiderites. The mineral was recently mentioned to occur in Vaca Huerta (Fleischer, et al., 1965) and in Odessa (El Goresy, 1965). We have found rutile in the meteorites Allegan, Bondoc, Estherville, Farming- ton, and Vaca Muerta; although nowhere an abundant phase, it appears to be rather widespread. Of the several meteorites in which it was observed, rutile is the most abundant in the Farmington L-group chondrite. There it occurs in fine lamellae in ilmenite. The ilmenite is only sparsely distributed within the . meteorite although wherever it does occur it is in moderately large clusters - up to 0.5 mn in diameter - and it then is usually associated with chromite as well as rutile (Buseck, et al., 1965), Optically, the rutile has a faintly bluish tinge when viewed in reflected, plane-polarized light with immersion objectives. -
Washington State Minerals Checklist
Division of Geology and Earth Resources MS 47007; Olympia, WA 98504-7007 Washington State 360-902-1450; 360-902-1785 fax E-mail: [email protected] Website: http://www.dnr.wa.gov/geology Minerals Checklist Note: Mineral names in parentheses are the preferred species names. Compiled by Raymond Lasmanis o Acanthite o Arsenopalladinite o Bustamite o Clinohumite o Enstatite o Harmotome o Actinolite o Arsenopyrite o Bytownite o Clinoptilolite o Epidesmine (Stilbite) o Hastingsite o Adularia o Arsenosulvanite (Plagioclase) o Clinozoisite o Epidote o Hausmannite (Orthoclase) o Arsenpolybasite o Cairngorm (Quartz) o Cobaltite o Epistilbite o Hedenbergite o Aegirine o Astrophyllite o Calamine o Cochromite o Epsomite o Hedleyite o Aenigmatite o Atacamite (Hemimorphite) o Coffinite o Erionite o Hematite o Aeschynite o Atokite o Calaverite o Columbite o Erythrite o Hemimorphite o Agardite-Y o Augite o Calciohilairite (Ferrocolumbite) o Euchroite o Hercynite o Agate (Quartz) o Aurostibite o Calcite, see also o Conichalcite o Euxenite o Hessite o Aguilarite o Austinite Manganocalcite o Connellite o Euxenite-Y o Heulandite o Aktashite o Onyx o Copiapite o o Autunite o Fairchildite Hexahydrite o Alabandite o Caledonite o Copper o o Awaruite o Famatinite Hibschite o Albite o Cancrinite o Copper-zinc o o Axinite group o Fayalite Hillebrandite o Algodonite o Carnelian (Quartz) o Coquandite o o Azurite o Feldspar group Hisingerite o Allanite o Cassiterite o Cordierite o o Barite o Ferberite Hongshiite o Allanite-Ce o Catapleiite o Corrensite o o Bastnäsite -
Titanium Dioxide Nanoparticles: Prospects and Applications in Medicine
nanomaterials Review Titanium Dioxide Nanoparticles: Prospects and Applications in Medicine Daniel Ziental 1 , Beata Czarczynska-Goslinska 2, Dariusz T. Mlynarczyk 3 , Arleta Glowacka-Sobotta 4, Beata Stanisz 5, Tomasz Goslinski 3,* and Lukasz Sobotta 1,* 1 Department of Inorganic and Analytical Chemistry, Poznan University of Medical Sciences, Grunwaldzka 6, 60-780 Poznan, Poland; [email protected] 2 Department of Pharmaceutical Technology, Poznan University of Medical Sciences, Grunwaldzka 6, 60-780 Poznan, Poland; [email protected] 3 Department of Chemical Technology of Drugs, Poznan University of Medical Sciences, Grunwaldzka 6, 60-780 Poznan, Poland; [email protected] 4 Department and Clinic of Maxillofacial Orthopedics and Orthodontics, Poznan University of Medical Sciences, Bukowska 70, 60-812 Poznan, Poland; [email protected] 5 Department of Pharmaceutical Chemistry, Poznan University of Medical Sciences, Grunwaldzka 6, 60-780 Poznan, Poland; [email protected] * Correspondence: [email protected] (T.G.); [email protected] (L.S.) Received: 4 January 2020; Accepted: 19 February 2020; Published: 23 February 2020 Abstract: Metallic and metal oxide nanoparticles (NPs), including titanium dioxide NPs, among polymeric NPs, liposomes, micelles, quantum dots, dendrimers, or fullerenes, are becoming more and more important due to their potential use in novel medical therapies. Titanium dioxide (titanium(IV) oxide, titania, TiO2) is an inorganic compound that owes its recent rise in scientific interest to photoactivity. After the illumination in aqueous media with UV light, TiO2 produces an array of reactive oxygen species (ROS). The capability to produce ROS and thus induce cell death has found application in the photodynamic therapy (PDT) for the treatment of a wide range of maladies, from psoriasis to cancer. -
Electronic Structure and Optical Properties of Prominent Phases of Tio2: First-Principles Study
Pramana – J. Phys. (2017) 89:5 © Indian Academy of Sciences DOI 10.1007/s12043-017-1400-5 Electronic structure and optical properties of prominent phases of TiO2: First-principles study SANTOSH SINGH and MADHVENDRA NATH TRIPATHI∗ Department of Pure and Applied Physics, Guru Ghasidas Vishwavidyalaya (Central University), Koni, Bilaspur 495 009, India ∗Corresponding author. E-mail: [email protected] Published online 19 June 2017 Abstract. First-principles study based on density functional theory (DFT) of two prominent phases, the rutile and the anatase phases, of titanium dioxide (TiO2) are reported within the generalized gradient approximation (GGA). Our calculated band structure shows that there is a significant presence of O-2p and Ti-3d hybridization in the valence bands. These bands are well separated from the conduction bands by a direct band gap value of 1.73 eV in the rutile phase and an indirect band gap value of 2.03 eV in the anatase phase, from to X. Our calculations reproduced the peaks in the conduction and valence band, are in good agreement with experimental observations. Our structural optimization for the rutile and anatase phase led to lattice parameter values of 4.62 Å and 2.99 Å rutile and 3.80 Å and 9.55 Å for anatase for a and c. The static dielectric values 7.0 and 5.1 for the rutile and anatase phases respectively are in excellent agreement with experimental results. Our calculation of optical properties reveals that maximum value of the transmittance in anatase phase of TiO2 may be achieved by considering the anisotropic behaviour of the optical spectra in the optical region for transparent conducting application. -
Volume Estimates for Equiangular Hyperbolic Coxeter Polyhedra
Algebraic & Geometric Topology 9 (2009) 1225–1254 1225 Volume estimates for equiangular hyperbolic Coxeter polyhedra CHRISTOPHER KATKINSON An equiangular hyperbolic Coxeter polyhedron is a hyperbolic polyhedron where all dihedral angles are equal to =n for some fixed n Z, n 2. It is a consequence of 2 Andreev’s theorem that either n 3 and the polyhedron has all ideal vertices or that D n 2. Volume estimates are given for all equiangular hyperbolic Coxeter polyhedra. D 57M50; 30F40 1 Introduction An orientable 3–orbifold, Q, is determined by an underlying 3–manifold, XQ and a trivalent graph, †Q , labeled by integers. If Q carries a hyperbolic structure then it is unique by Mostow rigidity, so the hyperbolic volume of Q is an invariant of Q. Therefore, for hyperbolic orbifolds with a fixed underlying manifold, the volume is a function of the labeled graph †. In this paper, methods for estimating the volume of orbifolds of a restricted type in terms of this labeled graph will be described. The orbifolds studied in this paper are quotients of H3 by reflection groups generated by reflections in hyperbolic Coxeter polyhedra. A Coxeter polyhedron is one where each dihedral angle is of the form =n for some n Z, n 2. Given a hyperbolic 2 Coxeter polyhedron P , consider the group generated by reflections through the geodesic planes determined by its faces, .P/. Then .P/ is a Kleinian group which acts on H3 with fundamental domain P . The quotient, O H3= .P/, is a nonorientable D orbifold with singular locus P.2/ , the 2–skeleton of P . -
Combustion Synthesis, Sintering, Characterization, and Properties
Hindawi Advances in Materials Science and Engineering Volume 2019, Article ID 9639016, 9 pages https://doi.org/10.1155/2019/9639016 Research Article Calcium Titanate from Food Waste: Combustion Synthesis, Sintering, Characterization, and Properties Siriluk Cherdchom,1 Thitiwat Rattanaphan,1 and Tawat Chanadee 1,2 1Department of Materials Science and Technology, Faculty of Science, Prince of Songkla University (PSU), Hat Yai, Songkhla 90110, &ailand 2Ceramic and Composite Materials Engineering Research Group (CMERG), Center of Excellence in Materials Engineering (CEME), Prince of Songkla University (PSU), Hat Yai, Songkhla 90110, &ailand Correspondence should be addressed to Tawat Chanadee; [email protected] Received 31 August 2018; Revised 20 December 2018; Accepted 3 January 2019; Published 12 February 2019 Academic Editor: Andres Sotelo Copyright © 2019 Siriluk Cherdchom et al. )is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Calcium titanate (CaTiO3) was combustion synthesized from a calcium source of waste duck eggshell, anatase titanium dioxide (A-TiO2), and magnesium (Mg). )e eggshell and A-TiO2 were milled for 30 min in either a high-energy planetary mill or a conventional ball mill. )ese powders were then separately mixed with Mg in a ball mill. After synthesis, the combustion products were leached and then sintered to produce CaTiO3 ceramic. Analytical characterization of the as-leached combustion products revealed that the product of the combustion synthesis of duck eggshell + A-TiO2 that had been high-energy-milled for 30 min before synthesis comprised a single perovskite phase of CaTiO3. -
CRYSTAL SRUKTUR of CALCIUM TITANATE (Catio3) PHOSPHOR DOPED with PRASEODYMIUM and ALUMINIUM IONS
CRYSTAL SRUKTUR OF CALCIUM TITANATE (CaTiO3) PHOSPHOR DOPED WITH PRASEODYMIUM AND ALUMINIUM IONS STRUKTUR KRISTAL FOSFOR KALSIUM TITANIA DIDOPKAN DENGAN ION PRASEODYMIUM DAN ALUMINIUM IONS Siti Aishah Ahmad Fuzi1* and Rosli Hussin2 1 Material Technology Group, Industrial Technology Division, Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor Darul Ehsan, Malaysia. 2 Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310 Skudai, Johor 1*[email protected], [email protected] Abstract The past three decades have witnessed rapid growth in research and development of luminescence phenomenon because of their diversity in applications. In this paper, Calcium Titanate (CaTiO3) was studied to find a new host material with desirable structural properties for luminescence-based applications. Solid state reactions o 3+ methods were used to synthesis CaTiO3 at 1000 C for 6 hours. Crystal structure of CaTiO3 co-doped with Pr 3+ and Al were investigated using X-Ray Diffraction (XRD) method. Optimum percentage to synthesis CaTiO3 was 3+ obtained at 40 mol%CaO-60 mol%TiO2 with a single doping of 1 mol%Pr . However, a crystal structure of 4 mol% of Al3+ co-doped with Pr3+ was determined as an optimum parameter which suitable for display imaging. Keywords: calcium titanate, anatase, rutile Abstrak Semenjak tiga dekad yang lalu telah menunjukkan peningkatan yang ketara bagi kajian dan pembangunan dalam bidang fotolumiscen. Peningkatan ini berkembang dengan meluas disebabkan oleh kebolehannya untuk diaplikasikan dalam pelbagai kegunaan harian. Dalam manuskrip ini, kalsium titania (CaTiO3) telah dikaji untuk mencari bahan perumah dengan sifat struktur yang bersesuaian bagi aplikasi luminescen. Tindak balas keadaan o pepejal telah digunakan bagi mensintesis CaTiO3 pada suhu 1000 C selama 6 jam. -
Hyperbolic Geometry, Surfaces, and 3-Manifolds Bruno Martelli
Hyperbolic geometry, surfaces, and 3-manifolds Bruno Martelli Dipartimento di Matematica \Tonelli", Largo Pontecorvo 5, 56127 Pisa, Italy E-mail address: martelli at dm dot unipi dot it version: december 18, 2013 Contents Introduction 1 Copyright notices 1 Chapter 1. Preliminaries 3 1. Differential topology 3 1.1. Differentiable manifolds 3 1.2. Tangent space 4 1.3. Differentiable submanifolds 6 1.4. Fiber bundles 6 1.5. Tangent and normal bundle 6 1.6. Immersion and embedding 7 1.7. Homotopy and isotopy 7 1.8. Tubolar neighborhood 7 1.9. Manifolds with boundary 8 1.10. Cut and paste 8 1.11. Transversality 9 2. Riemannian geometry 9 2.1. Metric tensor 9 2.2. Distance, geodesics, volume. 10 2.3. Exponential map 11 2.4. Injectivity radius 12 2.5. Completeness 13 2.6. Curvature 13 2.7. Isometries 15 2.8. Isometry group 15 2.9. Riemannian manifolds with boundary 16 2.10. Local isometries 16 3. Measure theory 17 3.1. Borel measure 17 3.2. Topology on the measure space 18 3.3. Lie groups 19 3.4. Haar measures 19 4. Algebraic topology 19 4.1. Group actions 19 4.2. Coverings 20 4.3. Discrete groups of isometries 20 v vi CONTENTS 4.4. Cell complexes 21 4.5. Aspherical cell-complexes 22 Chapter 2. Hyperbolic space 25 1. The models of hyperbolic space 25 1.1. Hyperboloid 25 1.2. Isometries of the hyperboloid 26 1.3. Subspaces 27 1.4. The Poincar´edisc 29 1.5. The half-space model 31 1.6. -
From Angled Triangulations to Hyperbolic Structures
http://dx.doi.org/10.1090/conm/541/10683 Contemporary Mathematics Volume 541, 2011 From angled triangulations to hyperbolic structures David Futer and Fran¸cois Gu´eritaud Abstract. This survey paper contains an elementary exposition of Casson and Rivin’s technique for finding the hyperbolic metric on a 3–manifold M with toroidal boundary. We also survey a number of applications of this technique. The method involves subdividing M into ideal tetrahedra and solving a system of gluing equations to find hyperbolic shapes for the tetrahedra. The gluing equations decompose into a linear and non-linear part. The solutions to the linear equations form a convex polytope A. The solution to the non-linear part (unique if it exists) is a critical point of a certain volume functional on this polytope. The main contribution of this paper is an elementary proof of Rivin’s theorem that a critical point of the volume functional on A produces a complete hyperbolic structure on M. 1. Introduction Around 1980, William Thurston showed that “almost every” 3–manifold M, whether closed or bounded, admits a complete hyperbolic metric [31]. When the boundary of M consists of tori, this metric is unique up to isometry [20, 24]. Thurston introduced a method for finding this unique metric. The idea was to subdivide the interior of M into ideal tetrahedra (tetrahedra whose vertices are removed), and then give those tetrahedra hyperbolic shapes that glue up coherently in M. The shape of a hyperbolic ideal tetrahedron can be completely described by a single complex number, namely the cross–ratio of its four vertices on the sphere at infinity. -
Suppression of Anatase to Rutile Phase Transformation of Niobium Doped Tio2 Synthesized by High Temperature Diffusion Technique
Online-ISSN 2411-2933, Print-ISSN 2411-3123 June 2015 Suppression of Anatase to Rutile Phase Transformation of Niobium doped TiO2 Synthesized by High Temperature Diffusion Technique Ogacho A. Aa*, Department of Physics, University of Nairobi, Box 30197 00100, Nairobi, Kenya [email protected] Ajuoga P b Department of Physics, University of Nairobi Box 30197 00100, Nairobi, Kenya [email protected] Aduda B. Oc Department of Physics, University of Nairobi Box 30197 00100, Nairobi, Kenya c [email protected] *Corresponding author email: [email protected] Abstract The effects of niobium doping (for doping concentrations: 0.02 – 0.06 at. % Nb5+) on the crystal structure of TiO2 prepared by high temperature diffusion method were investigated. The samples were characterized using energy dispersive X-ray fluorescence (EDXRF) and X- ray diffraction (XRD) spectroscopy to investigate the chemical compositions, phase compositions and crystallinity of the thin films respectively. Despite the expected high reutilization at high temperatures (>600oC), XRD results confirmed a significant suppression of anatase to rutile phase transformation at even a higher synthesis (850oC) temperature. Grain growth retardation was also 5+ 4+ observed in niobium doped TiO2, results which were attributed to Nb substitution of lattice Ti . Key words: Anatase, rutile, phase transformation, grain growth 1. Introduction Research on titanium dioxide light absorption has for the past four decades attracted considerable attention for possible broad applications in solar cells, photo catalysis, gas sensors, etc. TiO2 naturally occurs in three crystalline phases, that is, rutile, anatase and brookite. Of the three phases, ruitle is the most thermodynamically stable at room temperature. -
Novel Bottom-Up Sub-Micron Architectures for Advanced
NOVEL BOTTOM-UP SUB-MICRON ARCHITECTURES FOR ADVANCED FUNCTIONAL DEVICES by CHIARA BUSA’ A thesis submitted to the University of Birmingham for the degree of DOCTOR OF PHILOSOPHY Supervisor: Dr Pola Goldberg-Oppenheimer Department of Chemical Engineering College of Engineering and Physical Sciences University of Birmingham May 2017 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. Abstract This thesis illustrates two novel routes for fabricating hierarchical micro-to-nano structures with interesting optical and wetting properties. The co-presence of asperities spanning the two length scales enables the fabrication of miniaturised, tuneable surfaces exhibiting a high potential for applications in for instance, waterproof coatings and nanophotonic devices, while exploiting the intrinsic properties of the structuring materials. Firstly, scalable, superhydrophobic surfaces were produced via carbon nanotubes (CNT)-based electrohydrodynamic lithography, fabricating multiscale polymeric cones and nanohair-like architectures with various periodicities. CNT forests were used for manufacturing essential components for the electrohydrodynamic setup and producing controlled micro-to-nano features on a millimetre scale. The achieved high contact angles introduced switchable Rose- to-Lotus wetting regimes. Secondly, a cost-effective method was introduced as a route towards plasmonic bandgap metamaterials via electrochemical replication of three-dimensional (3D) DNA nanostructures as sacrificial templates. -
New Perspectives on Polyhedral Molecules and Their Crystal Structures Santiago Alvarez, Jorge Echeverria
New Perspectives on Polyhedral Molecules and their Crystal Structures Santiago Alvarez, Jorge Echeverria To cite this version: Santiago Alvarez, Jorge Echeverria. New Perspectives on Polyhedral Molecules and their Crystal Structures. Journal of Physical Organic Chemistry, Wiley, 2010, 23 (11), pp.1080. 10.1002/poc.1735. hal-00589441 HAL Id: hal-00589441 https://hal.archives-ouvertes.fr/hal-00589441 Submitted on 29 Apr 2011 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Journal of Physical Organic Chemistry New Perspectives on Polyhedral Molecules and their Crystal Structures For Peer Review Journal: Journal of Physical Organic Chemistry Manuscript ID: POC-09-0305.R1 Wiley - Manuscript type: Research Article Date Submitted by the 06-Apr-2010 Author: Complete List of Authors: Alvarez, Santiago; Universitat de Barcelona, Departament de Quimica Inorganica Echeverria, Jorge; Universitat de Barcelona, Departament de Quimica Inorganica continuous shape measures, stereochemistry, shape maps, Keywords: polyhedranes http://mc.manuscriptcentral.com/poc Page 1 of 20 Journal of Physical Organic Chemistry 1 2 3 4 5 6 7 8 9 10 New Perspectives on Polyhedral Molecules and their Crystal Structures 11 12 Santiago Alvarez, Jorge Echeverría 13 14 15 Departament de Química Inorgànica and Institut de Química Teòrica i Computacional, 16 Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona (Spain).