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Composite Microstructure of Spider ( Nephila Clavipes ) Dragline

MRS Online Proceedings Library 1993年第1期330卷 21-30页

作者： Brad Thiel Dennis Kunkel Keith Guess Christopher Viney Department of Materials Science and Engineering FB-10 University of Washington Seattle USA Department of Neurological Surgery RI-20 University of Washington Seattle USA Molecular Bioengineering Program Center for Bioengineering WD-12 University of Washington Seattle USA

Dragline fibers collected at a controlled silking rate from Nephila clavipes spiders were studied by analytical transmission electron microscopy (TEM). The physical microstructure consists of irregularly-shaped β-sheet crystallites (approx. 70–100 nm in diameter, and comprising approx. 50 volume per cent) in an amorphous matrix. Electron diffraction from single crystallites indicates an orthogonal unit cell with space group P21; the lattice parameters are a = 13.31 Å (inter-sheet repeat), b = 9.44 Å (inter-chain repeat within β-sheets) and c = 20.88 Å (intra-chain repeat). The crystallites are not truly periodic structures having long range positional order, but are better described as non-periodic layered structures, similar to the ordered structures formed when liquid crystalline random copolymers solidify. Electron energy loss spectroscopy (EELS) reveals chemical microstructure in the fibers. The matrix contains bands (approx. 200 nm wide) of alternately higher and lower nitrogen content. This variation cannot be explained in terms of known protein domains alone, and may reflect the presence of retained small-molecule species from secretory granules. Calcium is localized uniquely to the crystallites (at a concentration of approx. one calcium atom per 120 amino acid residues, as measured by inductively coupled plasma spectroscopy). Varying the calcium content may be one mechanism by which the spider can tailor the evolution of the microstructure, and hence the physical properties of the silk fiber.

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FIELD SAMPLING OF RESIDUAL AVIATION GASOLINE IN SANDY SOIL

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GROUND WATER MONITORING AND REMEDIATION 1991年第2期11卷 107-120页

作者： OSTENDORF, DW LEACH, LE HINLEIN, ES XIE, YF 1 David W. Ostendorf is an associate professor in the Environmental Engineering Program of the Civil Engineering Department at the University of Massachusetts (Civil Engineering Department University of Massachusetts Amherst MA 01003). His research interests include unconfined aquifer contamination hazardous waste site remediation and analytical modeling of problems in environmental fluid mechanics. Dr. Ostendorf is a registered professional engineer in Massachusetts and a member of the American Geophysical Union American Society of Civil Engineers Soil Science Society of America Water Pollution Control Federation and Association of Environmental Engineering Professors as well as the National Water Well Association.2 Lowell E. Leach is an environmental engineer with the Robert S. Kerr Environmental Research Laboratory of the U.S. Environmental Protection Agency (RS Kerr Environmental Research Laboratory U.S. EPA P.O. Box 1198 Ada OK74820). Leach received his B.S. ingeological engineering at the University of Oklahoma in 1959 and has been a registered professional engineer in Oklahoma since 1966. With 29 years of experience in field applications of geological engineering he is responsible for developing methodology for sampling ground water and subsurface materials for the Robert S. Kerr Environmental Research Laboratory.3 Erich S. Hinlein is a research assistant in the Environmental Engineering Program of the Civil Engineering Department at the University of Massachusetts (Civil Engineering Department University of Massachusetts Amherst MA 01003). His research interests include ground water pollution hazardous waste site investigation and transport processes in unconfined aquifers. Hinlein graduated with a B.S. in electrical and computer engineering from the University of Massachusetts at Amherst in May 1985 and entered the Environmental Engineering Master's Degree Program in January 1989.4 Yuefeng Xie is a postdoctoral research associate in the Environmental Engineering Program of the Civil E

Two complementary field sampling methods for the determination of residual aviation gasoline content in the contaminated capillary fringe of a fine, uniform, sandy soil were investigated. The first method featured field extrusion of core barrels into pint-size Mason jars, while the second consisted of laboratory partitioning of intact stainless steel core sleeves. The barrel extrusion procedure involved jar headspace sampling in a nitrogen-filled glove box, which delineated the 0.7m thick residually contaminated interval for subsequent core sleeve withdrawal from adjacent boreholes. Soil samples removed from the Mason jars (in the field) and sleeve segments (in the laboratory) were subjected to methylene chloride extraction and gas chromatographic analysis to compare their aviation gasoline content. The barrel extrusion sampling method yielded a vertical profile with 0.10m resolution over an essentially continuous 5.0m interval from the ground surface to the water table. The sleeve segment alternative yielded a more resolved 0.03m vertical profile over a shorter 0.8m interval through the capillary fringe. The two methods delivered precise estimates of the vertically integrated mass of aviation gasoline at a given horizontal location, and a consistent view of the vertical profile as well. In the latter regard, a 0.2m thick lens of maximum contamination was found in the center of the capillary fringe, where moisture filled all voids smaller than the mean pore size. The maximum peak was resolved by the core sleeve data, but was partially obscured by the barrel extrusion observations, so that replicate barrels or a half-pint Mason jar size should be considered for data supporting vertical transport analyses in the absence of sleeve partitions.

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ELASTOHYDRODYNAMICS OF BLADE COATING

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AICHE JOURNAL 1990年第4期36卷 587-597页

作者： PRANCKH, FR SCRIVEN, LE Coating Process Fundamentals Program Department of Chemical Engineering & Materials Science University of Minnesota Minneapolis MN 55455

Blade coating is the most common method of coating paper, and it is applied in coating magnetic suspensions and adhesives. Typically, the blade's upstream edge is clamped into a rigid holder so that the blade and substrate form a converging wedge. The translating substrate drags liquid into the wedge, where liquid forces develop and deflect the elastic blade, but it is loaded externally to counteract the deflection. Liquid dragged past the blade and thus the coating thickness depend on the elastohydrodynamic interaction among blade, liquid, and loading. Shell theory and lubrication flow theory describe the interaction by means of differential equations that are shown to be equivalent to Saita and Scriven's (1985) earlier formulation but that lead to a computationally more efficient analysis. Predictions computed agree with those of the earlier formulation and with experiments. Moreover, the new predictions illustrate effects of normal force loading and broaden the theory of blade coating.

关键词： Coating Techniques

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Poster contributions

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Hyperfine Interactions 1989年第1期47卷 433-589页

作者： A. Houlton J. Silver J. Guillin M. H. Desbois M. Lacoste D. Astruc F. Varret H. A. Goodwin D. Onggo Y. Maeda Y. Takashima H. Ohshio K. Toriumi M. Sorai P. Poganiuch P. Gütlich L. Wiehl U. Krafczyk A. Hauser H. Spiering M. Bardhan T. Birchall C. S. Frampton P. Kapoor Marion Tiedtke Gerhard Wortmann D. Petridis N. Gangas A. Simopoulos A. Kostikas N. H. J. Gangas A. Simgpoulos A. Meagher M. Billenstein R. Doerfler O. Leupold D. L. Nagy G. Ritter Gary J. Long Charles Gleitzer J. M. Fiddy I. Hall F. Grandjean G. J. Long U. Russo Z. Kucharski J. Suwalski Cz. Budrowski J. Vetrone Y. Calage R. Tortevois H. Fourari F. J. Berry M. I. Sarson C. Meyer K. Nagorny M. Łukasiak J. Panfil A. Bermudez R. Wordel F. E. Wagner A. A. Tyrer Y. Yoshida P. Fratzl W. Miekeley G. Vogl S. M. Dubiel Z. Homonnay K. Süvegh Cs. Szeles A. Vertes A. S. Saleh S. H. Mahmood J. E. Frackowiak R. Kmieć A. Z. Hrynkiewicz K. Krolas K. Tomala W. Adlassnig W. Potzel J. Moser W. Schiessl U. Potzel C. Schäfer M. Steiner G. M. Kalvius David W. Allen John S. Brooks Gavin L. Williams T. Nishida S. Saruwatari M. Hans G. K. Wolf M. Ghafari W. Keune C. T. Limbach U. Gonser A. Pösinger M. Reissner W. Steiner M. Kopcewicz S. M. Fries W. Zych D. Gryffroy R. E. Vandenberghe E. De Grave B. Huck J. Landes J. Hesse A. Labarta X. Obradors J. Tejada J. Pebler J. Pszczola K. Krop J. Zink Fernande Grandjean Dwayne E. Tharp O. Alan Pringle William J. James W. Lottermoser Elke Baum W. Treutmann G. Amthauer M. M. Abd-Elmeguid K. Gaebler W. Ludorf H. Micklitz R. D. Taylor V. Manns B. Scholz K. P. Schletz M. Braun E. F. Wassermann M. B. Madsen S. Linderoth S. Mørup M. D. Bentzon J. M. Knudsen E. Murad U. Schwertmann N. Choleva B. Lundgreen C. T. Jacobsen H. G. Jensen M. Olsen O. Kruse T. Ericsson U. Wagner S. v. Brandis H. Müller-Karpe J. Riederer M. Tellenbach C. Ulbert D. Hanzel Darko Hanzel H. Bilinski V. Nöthig G. Wiesinger S. S. Ismail P. Bottig H. H. A. Smit R. C. Thiel L. J. De Jongh S. Wells S. W. Charles A. D. Alhasan J. M. Williams A. Krämer J. Jing J. Van Wonterghem M Department of Chemistry and Biological Chemistry University of Essex Wivenhoe Park England UA-CNRS 807 Université du Maine Le Mans Cedex France UA-CNRS 35 Université Bordeaux I Talence Cedex France School of Chemistry University of New South Wales Kensington Australia Department of Chemistry Faculty of Science Kyushu University Fukuoka Japan Institute for Molecular Science Aichi Japan Chemical Thermodynamics Laboratory Faculty of Science Osaka University Osaka Japan Institut für Anorganische Chemie und Analytische Chemie Johannes-Gutenberg-Universität Mainz FRG Department of Chemistry McMaster University Hamilton Canada Institut für Atom- und Festkörperphysik Freie Universität Berlin Berlin 33 Germany Department of Physics NRC “Demokritos” Athens Greece “Demokritos” National Research Center for Physical Sciences Institute of Materials Science Aghia Paraskevi Attikis Greece Demokritos NRCPS Aghia Paraskevi Attikis Greece Athens Greece Laboratory of Applied Physics Technical University of Denmark Lyngby Denmark Adran Ffiscg CPGC Bangor G.B. Physikalisches Institute Universität Erlangen-Nürnberg Erlangen FRG Robert Bosch GmbH Nürnberg FRG Department of Chemistry University of Missouri-Rolla Rolla USA Department of Physics University of Liverpool Liverpool UK Departments of Chemistry Physics and the Graduate Centre for Materials Research University of Missouri-Rolla Rolla USA Laboratoire de Chimie du Solide Minéral Associé au CNRS No. 158 Service de Chimie Minérale Université de Nancy I Vandoeuvre-lez-Nancy Cedex France Institute de Physique Université de Liège Belgium Dipartimento di Chimica Inorganica Metallorganica ed Analytica Universita di Padova Italy Institute of Atomic Energy Otwock Poland Technical University of Warsaw Noakowskiego 3 Poland Department of Chemistry University of Birmingham Birmingham UK Institute of Physical Chemistry University of Hamburg Hamburg 13 FRG Laboratoire de Spectrométrie Physique Université de Grenob

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CHARACTERIZATION OF THE AREA UNDER LOSS MODULUS AND TAN-DELTA-TEMPERATURE CURVES - ACRYLIC POLYMERS AND THEIR SEQUENTIAL INTERPENETRATING POLYMER NETWORKS

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JOURNAL OF APPLIED POLYMER science 1987年第1期34卷 409-422页

作者： CHANG, MCO THOMAS, DA SPERLING, LH Polymer Science and Engineering Program Department of Chemical Engineering Materials Research Center #32 Lehigh University Bethlehem Pennsylvania 18015

Areas under the linear tan δ–temperature (tA) and linear loss modulus–temperature (LA) curves of the polyacrylate and polymethacrylate homologous series and their interpenetrating polymer networks (IPNs) were investigated. For poly(methyl acrylate), LA values are independent of crosslinking level through 25%, but tA decreases. With increasing side group length, on the other hand, tA remains nearly independent of side group length for both homologous series, having values near 50 and 65 (units of K) for the acrylate and methacrylate series, respectively. However, LA decreases steeply with increasing side group length. A phenomenological treatment of areas is presented in order to explain tA and LA behavior semiquantitatively. Both tA and LA exhibit areas characteristic of the structure of the particular polymers. The homopolymer LA areas are additive in determining the area under the corresponding curve for the IPN. This suggested a group contribution analysis for LA, where each moiety contributes specific values to the area.

关键词： INTERPENETRATING POLYMER NETWORKS

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The crystal structure of YBa2Cu306, thee = 1 phase of the superconductor YBa2Cu307 _ x

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Journal of materials Research 1987年第4期2卷 424-426页

作者： Swinnea, J.S. Steinfink, H. Materials Science and Engineering Program Department of Chemical Engineering The University of Texas at Austin Austin Texas 78712 United States

Black crystals, displaying a micaceous habit, result from heating the 90 K superconducting phase YBa2Cu307_;above 1050 °C. The crystals are tetragonal, PA/mmm, a = 3.863 (2) A, c — 11.830 (4) A, Z= 1, yOcai — 6.115 g/cm3. The 184 independent single-crystal reflections were used to refine the structure by least squares to R — 0.0374, wR — 0.0347. The structure contains Cu+in twofold coordination and corrugated layers of Cu2+— O. The Ba2+is in eightfold coordination between the Cu+and Cu2+layers and Y is in eightfold coordination between the Cu2+layers. © 1987, materials Research Society. All rights reserved.

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Thermodynamic Prediction of Sulfide Capacities in Na2O-SiO2 Melts

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ECS Proceedings Volumes 1987年第1期1987-7卷

作者： R. G. Reddy M. Blander B. Chen Department of Chemical and Metallurgical Engineering University of Nevada Reno Reno Nevada 89557-0047 Argonne National Laboratory Chemical Technology Division/Materials Science and Technology Program Argonne Illinois 60439-4837

Sulfide capacities of Na2O-SiO2 melts at 1473 and 1623 K were calculated a priori from a model using free energies of formation of Na2S and Na2O and the activities of Na2O in the binary Na2O-SiO2 melts. Our calculations are in excellent agreement with available experimental data and appear to be more more accurate than currently used empirical predictions of sulfide capacities, based on correlations with optical basicities using Pauling electronegativities.

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Electrochemical Reactions at the Electrode in Submerged Arc Welding

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ECS Proceedings Volumes 1987年第1期1987-7卷

作者： J. H. Kim R. H. Frost D. L. Olson M. Blander Argonne National Laboratory Chemical Technology Division/Materials Science and Technology Program Argonne Illinois 60439-4837 Center for Welding Research Department of Metallurgical Engineering Colorado School of Mines Golden Colorado 80401

The submerged arc welding process uses a D.C. arc under a protective slag cover to melt a consumable wire electrode. The purpose of this work is to investigate the relative influence of electrochemical and thermochemical reactions at the surface of the electrode of the composition on the liquid metal droplet. chemical analyses were carried out on the melted wire electrode tips and on the detached droplets for both reverse polarity (wire is anodic) and straight polarity (wire is cathodic) polarities. The results suggest that both thermochemical and electrochemical reactions are important in altering the composition of the detached droplet.

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A rationalization of stress-strain behavior of two-ductile phase alloys

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Metallurgical Transactions A 1986年第12期17卷 2209-2226页

作者： Ankem, S. Margolin, H. Engineering Materials Program Department of Chemical and Nuclear Engineering University of Maryland College Park Department of Metallurgy and Materials Science Polytechnic University Brooklyn

An extensive literature review indicated that the law of mixture rule can at times account for stress-strain behavior of two-ductile phase alloys in terms of the stress-strain behavior of component phases. In the present investigation, various factors which can contribute to the stress-strain behavior of two-ductile phase alloys are considered, using Ti-Mn alloys as the model system. Particular attention is focused on the effect of elastic, elasto-plastic, and plastic interactions between the phases on the stress-strain behavior. It is shown that the law of mixture cannot adequately explain the stress-strain behavior. The following equation is proposed to describe the stress-strain behavior of two-ductile phase alloys: Pα-β = fαPα c + fβPβ c + Iα-β p, where Pα-β is a given stress-strain property, fα and f/gb are respective volume fractions of α and β-phases, Pα c and Pβ c are corrected properties of α and β-phases, and Iα-β p is the interaction term. It is found that for α- β Ti-Mn alloys, for 0.2 pct yield strength, Iα-β p is positive, negative, or zero depending on the microstructure; but Iα-β p is always positive for the ultimate tensile strength and strain hardening rates and its magnitude depended on the microstructure. The reasons for the nature or sign of the interaction parameter for a given property are discussed in detail.

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RECENT ADVANCES IN INTERPENETRATING POLYMER NETWORKS

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POLYMER engineering AND science 1985年第9期25卷 517-520页

作者： SPERLING, LH Polymer Science and Engineering Program Department of Chemical Engineering Materials Research Center #32 Lehigh University Bethlehem Pennyslvania 18015

AbstractInterpenetrating polymer networks (IPN\'s) can be defined as a combination of two polymers in network form, at least one of which was synthesized and/or crosslinked in the immediate presence of the other. Historically, the science of IPN\'s began with the papers of J. R. Millar in 1960 on homo‐IPN\'s made from polystyrene, but the first recorded publication is a patent by J. W. Aylsworth in 1914. This latter system was based on phenol‐formaldehyde for one network, and sulfur cured natural rubber for the other network. Early academic laboratories interested in IPN\'s include the Frisch team at Detroit and SUNY, who soon added their former student, Danny Klempner, and Yuri Lipatov\'s team at the Ukranian SSR Academy of sciences in the USSR, as well as the author\'s laboratory. More recent academic teams interested in IPN\'s include Douglas Hourston at the University of Lancaster, England; Robert Cohen at MIT; S. C. Kim at the Korea Advanced Institute of science and Technology, Seoul, Korea; G. Meyer and J. M. Widmaier in Strasbourg, France; and many others. Numerous industrial laboratories are interested, noting that about 90 U.S. patients have been granted, most of them in the past ten years. Systems of special interest include the new thermoplastic IPN\'s, which are really hybrid materials between polymer blends and IPN\'s, and the IPN‐based RIM (reaction injection molding) materials. Other materials include the sequential IPN\'s and the SIN\'s, which have both polymers simultaneously polymerized, and the latex IPN\'s, which often exhibit core‐shell characte

关键词： POLYMERS

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