DOCSLIB.ORG

Structural Studies of Supramolecular Host-Guest Systems

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Structural Studies of Supramolecular Host-Guest Systems STRUCTURAL STUDIES OF SUPRAMOLECULAR HOST-GUEST SYSTEMS A Thesis Submitted to the College of Graduate Studies and Research In Partial Fulfillment of the Requirements For the Degree of Doctor of Philosophy In the Department of Chemistry University of Saskatchewan Saskatoon By ABDALLA H. KAROYO Copyright Abdalla Hamisi Karoyo, August 2014. All rights reserved. Permission To Use In presenting this thesis in partial fulfillment of the requirements for a Postgraduate degree from the University of Saskatchewan, I agree that the Libraries of this University may make it freely available for inspection. I further agree that permission for copying of this thesis in any manner, in whole or in part, for scholarly purposes may be granted by Professors L. D. Wilson and P. Hazendonk who supervised my thesis work or, in their absence, by the Head of the Department or the Dean of the College in which my thesis work was done. It is understood that any copying or publication or use of this thesis or part thereof for financial gain shall not be allowed without my written permission. It is also understood that due recognition shall be given to me and to the University of Saskatchewan in any scholarly use which may be made of any material in my thesis. Requests for permission to copy or to make other use of material in this thesis in whole or part should be addressed to: Head of the Department of Chemistry University Of Saskatchewan 110 Science Place Saskatoon, Saskatchewan S7N 5C9 Canada i Acknowledgements ﻬ In The Name of Allah The Most Beneficent The Most Merciful ﻬ I would like to express my sincere thanks to my supervisors Drs. Lee D. Wilson and Paul Hazendonk, to whom am deeply indebted by the support and guidance they accorded me throughout the course of my PhD program. My heartfelt thanks to the Department of Chemistry for the opportunity to do research and further my scientific career. I wish to thank the University of Lethbridge (U of L) for the opportunity to train and work on the solid-state NMR spectrometer; the University of Saskatchewan for the Graduate Teaching Fellowship; and the Natural Sciences and Engineering Research Council (NSERC) for the financial support. I am grateful to members of my PhD advisory committee, Drs. Richard Bowles, Steve Reid, and Oleg Dmitriev for their expert guidance. I wish to thank Drs. Sammynaiken and K. Brown, J. Maley, and K. Thoms (Saskatchewan Structural Sciences Center (SSSC)) for their technical support; Dr. P. Sidhu, Alex Borisov, and T. Montina (U of L) for their support in Solids NMR; Drs. Wajdi Zoghaib (Sultan Qaboos, Oman) and Hashim Ali (Arkansas State, USA) for their words of encouragement. To my colleagues in the Lab; Drs. Mohamed, Rui Guo and Jae Kwon, Dawn Pratt, Louis Poon, Chen Xue, Shagufta Younis, Leila Dehabadi, and Inimfon for their help in the Lab. I wish to thank Mohamed and Regeye, Denis and Catherine for making me feel at home away from home, especially during the early days of my stay in Canada. Lastly, my special thanks go to the most important person in this journey; my wife, Mwanajuma. I never realized how strong a woman she was until I embarked on this journey; her patience, love and encouragement allowed me to finish this journey. ii Dedications This thesis is dedicated to my wife and my sons Hamisi, Faisal, and Fadhil. To my parents; my mam Mwanasha Mwacharo, and my dad Hamisi Karoyo. To my sisters Mwanamisi, Bibi (twin), Mwanaulu, and Mwanasiti; and brothers Baya, Kassim, Dinar, and Juma. Thank you for your love and support. iii Abstract This research work details a systematic study of the structure and function of supramolecular host-guest systems. Host-guest inclusion complexes were formed between β- Cyclodextrin (β-CD) and its copolymers (as hosts), with several types of guest molecules both in aqueous solution and the solid state. The research is divided into two themes; (1) structural characterization and dynamic properties of the inclusion compounds of -CD with various guest systems in aqueous solution and the solid phase, and (2) heterogeneous adsorption and structural studies of β-CD based copolymers with various guest systems in aqueous solutions. The guest systems include alkyl and perfluoroalkyl carboxylates, perfluoroalkyl sulfonate, and p- nitrophenol (PNP) at variable experimental conditions. In the first theme (chapters 2–5), perfluorinated compounds (PFCs), namely; perfluorooctanoic acid (PFOA), perfluorobutyric acid (PFBA), and sodium perfluorooctanoate (SPFO) represent the guest molecules. The host-guest complexes in the solid state were prepared using dissolution and slow cool methods at variable host/guest mole ratios (i.e., 1:1 and 2:1). The complexes were further characterized using 19F/13C DP/MAS and CP/MAS solid-state NMR spectroscopy. The solution state complexes were prepared in D2O for structural characterization using 1H/19F NMR spectroscopy. The NMR studies were complemented using FT-IR, thermal analyses (DSC, and TGA), and powder X-ray diffraction (PXRD). Evidence for the formation of host-guest inclusion compounds (ICs) was provided using CP/MAS solids NMR spectroscopy and complexation-induced chemical shift (CIS) values of 1H/19F nuclei in aqueous solution. The β-CD/PFC ICs displayed variable guest geometry and hydration states as determined by the host- guest stoichiometry and the conformation of the guest. PFOA and SPFO form 1:1 and 2:1 ICs with β-CD, wherein the guest adopts a range of gauche and trans conformations, respectively. iv 1:1 host-guest complexes were concluded for short perfluorocarbon chains (i.e., PFBA) where the gauche conformation of the PFC guest in the bound state was favoured. The phase purity of the β-CD/PFC ICs was assessed using DSC and 19F DP/MAS NMR spectroscopy at ambient and variable temperature (VT) conditions. The complexes prepared by the slow cool method were found to be of relatively high phase purity when compared to complexes prepared by the dissolution method. However, a simple modified dissolution method was developed to afford complexes with greater phase purity. The phase purity of the complexes was further assessed using deconvolution analyses of the 19F DP/MAS NMR resonance line 1 13 19 shapes. H/ C/ F NMR relaxation (T1/T2/T1ρ) data of the phase pure β-CD/PFC ICs in the solid state revealed variable host and guest dynamics that were governed by dipolar coupling, H- bonding, and combinations of host-guest motional dynamics that involve peripheral and hydrate water within the cavity of β-CD. Coupling constants of the simulated 19F spectra and deconvolution analyses of selected 19F nuclei were used to supplement the 19F NMR relaxation results. In general, two types of motional dynamics of the guest were concluded; (i) 120° rotational jumps of the fluoromethyl (CF3) group at the termini of the PFC chain, and (ii) axial (libration) motion of the entire PFC chain. The rotational and axial dynamics of the guest in the complexes differ in their distribution and magnitude, in accordance with the host-guest stoichiometry and the geometry of the guest within the host. In the second theme (chapters 6–8), β-CD based copolymers were used as host materials. The structural characterization of a soluble poly-CD material (known as HDI-1) revealed that the solution behaviour of such polymeric hosts are sensitive to the presence of guest compounds such as p-nitrophenol (PNP) (i.e. chemo-responsive), as well as temperature variations (i.e. thermo-responsive). The host-guest chemistry of the soluble poly-CD material, as studied by 2-D v solution NMR and induced circular dichroism (ICD) spectroscopy, indicates that PNP was bound within the cavity sites of β-CD and the interstitial domains of the copolymer (cf. Scheme 1.6 and chapter 6). The observed responsive nature of such polymeric host materials to temperature variation and chemical potential resembles behaviour characteristic of ‘smart materials’. Herein, ‘smart materials’ refer to systems which are responsive to external stimuli (e.g. temperature and chemical). The adsorption properties of the soluble (HDI-1) and insoluble (HDI-3 and -6) poly-CD adsorbents with octyl and perfluorooctyl carboxylate and sulfonate anions were estimated using the Sips and BET models. The hydrocarbon (HC) and fluorocarbon (FC) anions form monolayer and multilayer structures at the surface of the polymeric adsorbents, respectively. The formation of layered structures was controlled by the relative hydrophobicity of the alkyl/perfluoroalkyl chains and their mutual miscibility with the adsorbent surface. Other factors include the inductive effects of the alkyl/perfluoroalkyl head groups and their interactions with aqueous solvent or dipolar domains of the adsorbent surface. The adsorbed species at the liquid-solid interface were characterized using FT-IR spectroscopy, thermal analyses, and contact angle. vi TABLE OF CONTENTS Permission To Use …..…..………………….…………………………………….i Acknowledgements …..……………………………………………………………ii Dedications ……………………………………………………………….iii Abstract …..………………………………………………………...iv-vi Table of Contents .…....……………….….…………………………………....vii Table of Contents ………………………………………….………………viii-xvi Appendices ………………...……………………………………...xvii-xviii List of Tables …..…..…………..…….………………………...………xix-xx List of Schemes …...…………..………..………………………………xxi-xxiv List of Figures ….……………..……………………………………xxv-xxxiii List of Abbreviations …...…………..……..……………………….……..xxxiv-xxxv vii Chapter 1…………………………………………………………………………………………... 1 1. Introduction………………………………………………………………………………... 1 1.1. Introduction
Load more

Recommended publications
  • Arxiv:1810.10187V3 [Physics.Ins-Det] 10 Jan 2019 to Minimize Longitudinal Heat flow While Satisfying One’S Electrical Impedance and Shape (E.G
    Properties of selected structural and flat flexible cabling materials for low temperature applications M. Daala,∗, N. Zobrista, N. Kellarisd,e, B. Sadouletb, M. Robertsonc aDepartment of Physics, University of California, Santa Barbara CA 93106-9530 bDepartment of Physics, University of California, Berkeley CA 94720-7300 cDepartment of Physics, University of California, Davis CA 95616-8677 dDepartment of Mechanical Engineering, University of Colorado Boulder, 80309-0427 eMaterials Science and Engineering Program, University of Colorado, Boulder, 80309-0596 Abstract We present measurements of the low temperature thermal conductivity for materials useful in the construction of cryogenic supports for scientific instrumentation and in the fabrication of flat flexible cryogenic cabling. The materials we measure have relatively low thermal conductivity. We present a method for measuring the heat transfer coefficient of flat cabling and show, using an example, that the thermal conductivity of a flex cable is reasonably well predicted by composing the thermal conductivities of its constituent material layers. Room temperature physical and mechanical data is given for the materials studied, as well as an overview of relevant materials science and manufacturing details. Materials include Timet Ti 15-3 and Ti 21S, Materion alloy vit105 (LM105) in amorphous state, ATI Metals Nb-47Ti, Johnson Matthey nitinol (NiTi), Mersen graphite grade 2020, DuPont Pyralux coverlay and Vespel SCP-5050, and Fralock Cirlex polyimide sheets. All data is in the temperature range 0:05 to 2 K, and up to 5 K for SCP-5050. Keywords: Thermal conductivity, Heat transfer coefficient, Cryogenic, Structural materials, Support structures, Flat flexible cables, Superconducting cables, Low temperature, Titanium alloys, Bulk metallic glass, vit105, LM105, Cirlex, Vespel, Pyralux, NbTi, Ti 15-3-3-3, Ti 21S, Nitinol, NiTi, Transition Temperature 1.
    [Show full text]
  • DUPONT DATA BOOK SCIENCE-BASED SOLUTIONS Dupont Investor Relations Contents 1 Dupont Overview
    DUPONT DATA BOOK SCIENCE-BASED SOLUTIONS DuPont Investor Relations Contents 1 DuPont Overview 2 Corporate Financial Data Consolidated Income Statements Greg Friedman Tim Johnson Jennifer Driscoll Consolidated Balance Sheets Vice President Director Director Consolidated Statements of Cash Flows (302) 999-5504 (515) 535-2177 (302) 999-5510 6 DuPont Science & Technology 8 Business Segments Agriculture Electronics & Communications Industrial Biosciences Nutrition & Health Performance Materials Ann Giancristoforo Pat Esham Manager Specialist Safety & Protection (302) 999-5511 (302) 999-5513 20 Corporate Financial Data Segment Information The DuPont Data Book has been prepared to assist financial analysts, portfolio managers and others in Selected Additional Data understanding and evaluating the company. This book presents graphics, tabular and other statistical data about the consolidated company and its business segments. Inside Back Cover Forward-Looking Statements Board of Directors and This Data Book contains forward-looking statements which may be identified by their use of words like “plans,” “expects,” “will,” “believes,” “intends,” “estimates,” “anticipates” or other words of similar meaning. All DuPont Senior Leadership statements that address expectations or projections about the future, including statements about the company’s strategy for growth, product development, regulatory approval, market position, anticipated benefits of recent acquisitions, timing of anticipated benefits from restructuring actions, outcome of contingencies, such as litigation and environmental matters, expenditures and financial results, are forward looking statements. Forward-looking statements are not guarantees of future performance and are based on certain assumptions and expectations of future events which may not be realized. Forward-looking statements also involve risks and uncertainties, many of which are beyond the company’s control.
    [Show full text]
  • Outgassing of Technical Polymers PEEK, Kapton, Vespel & Mylar
    Ivo Wevers Outgassing of Technical Polymers PEEK, Kapton, Vespel & Mylar Vacuum, Surfaces & Coatings Group Technology Department Outline • Part 1: Introduction • Polymers in vacuum technology • Outgassing of water : metallic surface vs polymer • Part 2: Outgassing at Room Temperature • Outgassing measurements of PEEK, Kapton, Mylar and Vespel samples • Fitting with 2-step and 3-step models • Diffusion coefficient, moisture content and decay time constant • Part 3: Attenuation of Polymers Outgassing • Effects of bakeout and venting on pump-down curves • Effects of desication with silica gel • Conclusions & Future Vacuum, Surfaces & Coatings Group Ivo Wevers ARIES 2021 Technology Department 2 Part 1: Introduction • Polymers in vacuum technology • Outgassing of water : metallic surface vs polymer Vacuum, Surfaces & Coatings Group Ivo Wevers ARIES 2021 Technology Department 3 Polymers in vacuum technology Polymers are sometimes the only option as seal/insulator PEEK, Kapton and Vespel -> bakeout temperatures of 150-200C° Vacuum, Surfaces & Coatings Group Ivo Wevers ARIES 2021 Technology Department 4 Polymers in vacuum technology Polymers are sometimes the only option as seal/insulator PEEK, Kapton and Vespel -> bakeout temperatures of 150-200C° Guarantee a certain beam lifetime or certain operation conditions Outgassing limit (maximum pressure to be reached in 24 hours) is defined for each machine AND the residual gas analysis free of contaminants Acceptance test prior to installation: - Pumpdown will define the outgassing rate and variation
    [Show full text]
  • Dupont™ Kalrez® KVSP™ Valve Stem Packing Technical Guidelines and Design to Improve Process Control and Minimize Fugitive Emissions
    DuPont™ Kalrez® KVSP™ Valve Stem Packing Technical Guidelines and Design to Improve Process Control and Minimize Fugitive Emissions Technical Information—Rev. 4, March 2019 Introduction DuPont™ Kalrez® Valve Stem Packing (KVSP™) systems can help to significantly reduce fugitive emissions and improve process control through the innovative use of Kalrez® perfluoroelastomer parts combined with other proven packing materials. Graphite packing systems can meet fugitive emissions requirements but restrict valve movement, leading to inconsistent process control. Polytetrafluoroethylene (PTFE) has excellent process control response characteristics but cannot contain fugitive emissions when temperature cycling is involved in conjunction with operational cycling. Kalrez® packing systems overcome these deficiencies, as well as reducing leak rates to near-bellows performance. Kalrez® is chemically an elastomeric PTFE derived from tetrafluoroethylene (TFE), the same base monomer. It provides a unique combination of chemical resistance and inertness like PTFE, but with a higher temperature service limit and no tendency to cold flow. The chemical structure remains cross-linked and stable at high temperatures and does not move under load or deformation. Its resiliency and memory provide improved sealing for control valve stems. Using Kalrez® V-rings backed up with more rigid components of carbon fiber-reinforced PTFE (DuPont™ Vespel® CR-6100) has proven to be a major advancement in improving process control and reducing leakage to less than 1 ppm, or below the plant’s background level. Kalrez® perfluoroelastomer packing systems increase a valve’s ability to react quickly and smoothly to process changes (Figure 1). Kalrez® KVSP™ reduces process control variability to the control system’s capability, resulting in improvements to both yield and product quality on specification.
    [Show full text]
  • Application of Polyimide Actuator Rod Seals
    (NASA-CR- 120878) APPLICATION OF POLYIiIDE N72-245306 ACTUATOR ROD SEALS AoH. Hatermann, et al (Boeing Co,, Seattle, Wash,) 30 Jan. 1972 177 p CSCL 11A Unclas G3/15 28867 I CR-I 20878 D6-54351 A A~ APPLICATION OF POLYIMIDE ACTUATOR ROD SEALS by A. W. Waterman, B. F. Gay, E. D. Robinson, S. K. Srinath, W. G. Nelson THE BOEING COMPANY prepared for NATIONAL AERONAUTICS AND SPACE ADMINISTRATION NASA Lewis Research Center Contract NAS3-14317 ! William F. Hady, Project Manager 1. Report No. 2. Government Accession No. 3. Recipient's Catalog No. CR- 120878 4. Title and Subtitle 5. Report Date APPLICATION OF POLYIMIDE ACTUATOR ROD SEALS January 30, 1972 6. Performing Organization Code 7. Author(s) A. W. Waterman, B. F. Gay, E. D. Robinson, 8. Performing Organization Report No. S. K. Srinath, and W. G. Nelson D6-54351 9. Performing Organization Name and Address 10. Work Unit No. YON 1347 The Boeing Company, Commercial Airplane Group 11. Contractor Grant No. P.O. Box 3707, Seattle, Washington 98124 NAS3-14317 13. Type of Report and Period Covered 12. Sponsoring Agency Name and Address CONTRACTOR REPORT National Aeronautics and Space Administration 7/1/70-1/30/72 Washington, D.C. 20546 14. Sponsoring Agency Code 15. Supplementary Notes Project Manager: W. F. Hady, Fluid System Component Division, NASA Lewis Research Center, Cleveland, Ohio 16. Abstract Development of polyimide two-stage hydraulic actuator rod seals for application in high-performance aircraft was accomplished. The significant portion of the effort was concentrated on optimization of the chevron and K-section second-stage seal geometries to satisfy the requirements for operation at 4500K (3500F) with dynamic pressure loads varying between 1.379 x 106 N/m2 (200 psig) steady-state and 1.043 x 107 N/m2 (1500 psig) impulse cycling.
    [Show full text]
  • Materials Matter™
    MATERIALS MATTER™ Lower Levelized Cost of Energy (LCOE) through DuPont Innovation MATERIALS MATTER™ FOR BETTER LONG-TERM PV SYSTEM PERFORMANCE AND HIGHER FINANCIAL RETURNS DuPont has a rich heritage of innovation and leadership in the PV industry. It all began more than 55 years ago when our scientists created the first purified silicon for Bell Labs for use in the PV market. Since then, our broad and growing portfolio of materials has enabled significant leaps in module efficiency, reliability and overall system cost reduction. We are committed to continually driving technology innovation and have been granted nearly 200 PV worldwide patents since 2008, with more than 1,300 patent applications currently pending. In 2011, DuPont spent $2 billion U.S. dollars on research and development, with a significant portion focused on advancing the efficiency, lifetime and cost competitiveness of solar energy. We’ve also invested hundreds of millions of U.S. dollars in supply expansions over the past few years to support long-term industry growth. Today, DuPont offers the broadest materials portfolio time-tested for decades in more than five trillion in PV and provides six of the eight most critical materials panel-hours of outdoor PV field installations all around for manufacturing solar modules. These materials are the world. That’s trillions more hours of real PV exposure not only innovative, they have delivered demonstrable than other material providers in the industry. results, including: nearly doubling cell efficiency over 12 years; providing greater reliability and extending Looking ahead, we aim to increase efficiency well beyond system lifetime—with 30+ years of proven backsheet 20% and extend system lifetime toward 40 years, while performance; and reducing overall system cost with increasing system safety and reducing cost.
    [Show full text]
  • Material Safety Data Sheet
    Du Pont Page 1 Material Safety Data Sheet ---------------------------------------------------------------------- "VESPEL" POLYIMIDE PARTS AND SHAPES ALL IN SYNONYM LIST VSP001 VSP001 Revised 26-JAN-2007 Printed 02/11/2009 ---------------------------------------------------------------------- Substance ID :130000026921 ---------------------------------------------------------------------- CHEMICAL PRODUCT/COMPANY IDENTIFICATION ---------------------------------------------------------------------- Material Identification "VESPEL" is a registered trademark of DuPont. Corporate MSDS Number : DU003855 Tradenames and Synonyms "VESPEL" SP-1, "VESPEL" SP-3, "VESPEL" SP-21, "VESPEL" SP-22, "VESPEL" SP-26 "VESPEL" SP-101, "VESPEL" SP-102, "VESPEL" SP-202 # "VESPEL" SP-211, "VESPEL" SP-214, "VESPEL" SP-215, "VESPEL" SP-221, "VESPEL" SP-224, "VESPEL" SP-262, "VESPEL" SP-2515, "VESPEL" SP-2624 "VESPEL" ST-2010, "VESPEL" ST-2010G, "VESPEL" ST-2010H, "VESPEL" ST-2030, Company Identification MANUFACTURER/DISTRIBUTOR DuPont Engineering Polymers 1007 Market Street Wilmington, DE 19898 PHONE NUMBERS Product Information : 1-800-441-7515 Transport Emergency : 1-800-424-9300 Medical Emergency : 1-800-441-3637 ---------------------------------------------------------------------- COMPOSITION/INFORMATION ON INGREDIENTS ---------------------------------------------------------------------- Components Material CAS Number % Du Pont VSP001 Page 2 Material Safety Data Sheet POLY-N,N'-(p,p'-OXYDIPHENYLENE) 25038-81-7 30-100 PYROMELLITIMIDE GRAPHITE 7782-42-5 0-65
    [Show full text]
  • Material Chemical & Physical Properties Tensile
    THIS GUIDE IS Go to INTERACTIVE ePlastics.com CLICK ON EACH ITEM TO GO TO ITS DESCRIPTION MATERIAL COST CHEMICAL & PHYSICAL TENSILE STRENGTH PROPERTIES UV RESISTANCE & FLEXURAL STRENGTH VISIBLE LIGHT TRANSMISSION IMPACT STRENGTH CHEMICAL RESISTANCE & HARDNESS MAXIMUM HEAT DEFLECTION DIELECTRIC PROPERTIES OPERATING TEMPERATURE TEMPERATURE EXPRESS DISCLAIMER: THE INFORMATION PRESENTED IN OUR MATERIAL SELECTION GUIDE AND OUR WEB SITES IS BASED ON OUR 99 YEARS PROVIDING PLASTIC MATERIALS AND SOLUTIONS. WE SINCERELY HOPE YOU FIND THE INFORMATION HELPFUL IN YOUR SEARCH FOR ANSWERS. THE INFORMATION SOURCES ARE FROM THE WIDE SELECTION OF PLASTIC MANUFACTURERS THAT WE DISTRIBUTE FOR. THERE ARE MANY MORE PLASTICS AVAILABLE THAN LISTED HEREIN AND MAY CONTAIN ADDITIVES THAT CAN ALTER THE PHYSICAL PROPERTIES. THE EXPRESS INTENTION OF RIDOUT PLASTICS IS TO HELP YOU NARROW YOUR SEARCH, NOT TO PRESCRIBE A "FITNESS OF USE" FOR ANY PARTICULAR USE. AS WITH ALL NEW APPLICATIONS, ONE MUST TEST THE PLASTIC FOR THE USE AND THEN MAKE APPROVALS OF YOUR OWN. SEPT 2013 VER. 1 CHEMICAL & PHYSICAL BACK TO NEXT PROPERTIES START PAGE THERMOPLASTIC/ THERMOPLASTIC THERMOSET THERMOSET AMORPHOUS FIBERGLASS/HIGH PRESSURE AMORPHOUS SEMI-CRYSTALLINE POLYAMIDE-IMIDES LAMINATES Advantages Advantages Advantages Advantages . High Temperature resistance . Softens over a wide . Opaque . Highest temperature (+200°F) temperature range with no . Better chemical resistance resistance (+400°F) . Fire retardant class 1 sharp melting point . Better resistance to stress . High chemical resistance . Strength to weight ratio Good adhesive bonding cracking . High weight-bearing abilities . Dimensionally Stable Good formability . Better fatigue resistance and mechanical stability under . Thermal Conductivity . Ease of machining . Good for structural weight- high pressure and temperature Disadvantages .
    [Show full text]
  • 2 0 0 1 a N N U a L R E P O
    2001 ANNUAL REPORT DuPont at 200 In 2002, DuPont celebrates its 200th anniversary. The company that began as a small, family firm on the banks of Delaware’s Brandywine River is today a global enterprise operating in 70 countries around the world. From a manufacturer of one main product – black powder for guns and blasting – DuPont grew through a remarkable series of scientific leaps into a supplier of some of the world’s most advanced materials, services and technologies. Much of what we take for granted in the look, feel, and utility of modern life was brought to the marketplace as a result of DuPont discoveries, the genius of DuPont scientists and engineers, and the hard work of DuPont employees in plants and offices, year in and year out. Along the way, there have been some exceptional constants. The company’s core values of safety, health and the environment, ethics, and respect for people have evolved to meet the challenges and opportunities of each era, but as they are lived today they would be easily recognizable to our founder. The central role of science as the means for gaining competitive advantage and creating value for customers and shareholders has been consistent. It would be familiar to any employee plucked at random from any decade of the company’s existence. Yet nothing has contributed more to the success of DuPont than its ability to transform itself in order to grow. Whether moving into high explosives in the latter 19th century, into chemicals and polymers in the 20th century, or into biotechnology and other integrated sciences today, DuPont has always embraced change as a means to grow.
    [Show full text]
  • 2018-CENPA-Annual-Report.Pdf
    ANNUAL REPORT Center for Experimental Nuclear Physics and Astrophysics University of Washington July 23, 2018 Sponsored in part by the United States Department of Energy under Grant #DE-FG02-97ER41020. This report was prepared as an account of work sponsored in part by the United States Government. Neither the United States nor the United States Department of Energy, nor any of their employees, makes any warranty, expressed or implied or assumes any legal liability or responsibility for accuracy, completeness or usefulness of any information, apparatus, product or process disclosed, or represents that its use would not infringe on privately-owned rights. Cover design by Gary Holman. Photos from left: Nathan Froemming inspecting upstream muon beam line for the Muon g 2 experiment. Krishna Venkateswara assembling one − of the four tiltmeters at LIGO Livingston Observatory. Brent Graner and Drew Byron examining the superconducting solenoid to be used for the 6He-CRES experiment. David Hertzog calibrating the beam-entrance counter for the Muon g 2 experiment. Ali Ashtari − Esfahani while exchanging a quarter-wave plate assembly on the Project 8 Phase II tritium compatible waveguide setup. UW CENPA Annual Report 2017-2018 July 2018 i INTRODUCTION The Center for Experimental Nuclear Physics and Astrophysics, CENPA, was established in 1998 at the University of Washington as the institutional home for a broad program of research in nuclear physics and related fields. Research activities — with an emphasis on fundamental symmetries and neutrinos — are conducted locally and at remote sites. In neutrino physics, CENPA is the lead US institution in the KATRIN tritium β-decay experiment, the site for experimental work on Project 8, and a collaborating institution in the MAJORANA 76Ge 0νββ experiment.
    [Show full text]
  • Thermal Design and Performance of the Gamma-Ray Spectrometer for the MESSENGER Spacecraft
    Thermal Design and Performance of the Gamma-Ray Spectrometer for the MESSENGER Spacecraft M. Burks, C. P. Cork, D. Eckels, E. Hull, N.W. Madden, W. Miller, J. Goldsten, E. Rhodes, B. Williams Abstract-- A gamma-ray spectrometer (GRS) has been built and and periapsis only 200 km from the surface of the planet. The delivered to the MESSENGER spacecraft which launched on mission will last one Earth year (~ four Mercury years). August 3, 2004, from Cape Canaveral, Florida. The GRS, a part of Mercury has little atmosphere and a weak magnetic field, and seven scientific instruments on board MESSENGER, is based on a is therefore largely unshielded from cosmic and solar radiation. coaxial high-purity germanium detector. Gamma-ray detectors The gamma-ray spectrometer (GRS), one component of the based on germanium have the advantage of providing excellent energy resolution, which is critical to achieving the science goals of MESSENGER Gamma-Ray and Neutron Spectrometer (GRNS) the mission. However, germanium has the disadvantage that it must instrument, will record the characteristic gamma rays emitted operated at cryogenic temperatures (typically ~80 K). This from surface elements as a result of reactions with cosmic rays requirement is easy to satisfy in the laboratory but difficult near and, in conjunction with the other spectrometers, help determine Mercury, which has an extremely hot thermal radiation the surface composition. environment. To cool the detector, a Stirling cycle mechanical cooler is employed. In addition, radiation and conduction techniques are used to reduce the GRS heat load. Before delivering the flight sensor, a complete thermal prototype was built and tested.
    [Show full text]
  • Aviation Week & Space Technology
    UK-Japan Should the USAF Quebec’s Drive Fighter Proposal Lead in Space? To Digital $14.95 APRIL 3-16, 2017 RICH MEDIA A320neo EXCLUSIVE Report Card Digital Edition Copyright Notice The content contained in this digital edition (“Digital Material”), as well as its selection and arrangement, is owned by Penton. and its affiliated companies, licensors, and suppliers, and is protected by their respective copyright, trademark and other proprietary rights. Upon payment of the subscription price, if applicable, you are hereby authorized to view, download, copy, and print Digital Material solely for your own personal, non-commercial use, provided that by doing any of the foregoing, you acknowledge that (i) you do not and will not acquire any ownership rights of any kind in the Digital Material or any portion thereof, (ii) you must preserve all copyright and other proprietary notices included in any downloaded Digital Material, and (iii) you must comply in all respects with the use restrictions set forth below and in the Penton Privacy Policy and the Penton Terms of Use (the “Use Restrictions”), each of which is hereby incorporated by reference. Any use not in accordance with, and any failure to comply fully with, the Use Restrictions is expressly prohibited by law, and may result in severe civil and criminal penalties. Violators will be prosecuted to the maximum possible extent. You may not modify, publish, license, transmit (including by way of email, facsimile or other electronic means), transfer, sell, reproduce (including by copying or posting on any network computer), create derivative works from, display, store, or in any way exploit, broadcast, disseminate or distribute, in any format or media of any kind, any of the Digital Material, in whole or in part, without the express prior written consent of Penton.
    [Show full text]