Mesure Des Propriétés Mécaniques Des Matériaux Poreux À L’Aide D’Un Transducteur Électrodynamique Sans Fer,
2010
École de technologie supérieure (ETS)
Mesure Des Propriétés Mécaniques Des Matériaux Poreux À L’Aide D’Un Transducteur Électrodynamique Sans Fer, Nicolas Dauchez, Olivier Doutres, Jean-Michel Génevaux, Guy Lemarquand, Sylvain Mezil
Olivier Doutres Ph.D.
Un banc de mesure des propriétés mécaniques des matériaux poreux est présenté. Il permet d'étendre les méthodes quasistatiques basées sur la compression d'un échantillon vers les hautes fréquences. Les méthodes quasistatiques sont limitées en fréquence (< 100 Hz) parce qu'elles négligent les éléments inertiels et le couplage avec l'air ambiant. Dans la méthode présentée, l'échantillon est placé dans une cavité étanche pour limiter l'effet de l'air ambiant et ainsi permettre une meilleure estimation du facteur de perte. Un transducteur électrodynamique a été conçu spécifiquement pour permettre une excitation sur une large gamme de fréquence : les premiers modes de l'équipage mobile sont au dela de 5 kHz. De plus, son architecture sans fer et sans suspension viscoélastique permet de l'utiliser comme capteur par le biais de son impédance électrique. L'impédance mécanique de l'échantillon est obtenue en inversant le modèle électromécanique du transducteur et les propriétés viscoélastiques - module d'Young et facteur de perte - sont obtenues par recalage d'un modèle analytique utilisant la théorie de Biot-Allard. Les résultats sont présentés pour une mousse polymère à cellule ouvertes. Le calcul des incertitudes montre que la méthode permet une bonne estimation jusque 500 Hz et permet de définir les conditions d'extension de la plage de fréquence.
Characterization And Measurement Of Passive And Active Metamaterial Devices,
2010
Air Force Institute of Technology
Characterization And Measurement Of Passive And Active Metamaterial Devices, Christopher A. Lundell
Theses and Dissertations
This document addresses two major obstacles facing metamaterial development: uncertainty in the characterization of electromagnetic field behavior in metamaterial structures and the relatively small operational bandwidth of metamaterial structures. To address the first obstacle, a new method to characterize electromagnetic field behavior in a metamaterial is presented. This new method is a bistatic radar cross section (RCS) measurement technique. RCS measurements are well-suited to measuring bulk metamaterial samples because they show frequency dependence of scattering angles and offer common postprocessing techniques that can be useful for visualizing results. To address the second obstacle, this document characterizes the effectiveness of an …
Optical And Electrical Characterization Of Bulk Grown Indium-Gallium-Arsenide Alloys,
2010
Air Force Institute of Technology
Optical And Electrical Characterization Of Bulk Grown Indium-Gallium-Arsenide Alloys, Austin C. Bergstrom
Theses and Dissertations
Advances in crystal growth techniques have allowed increased quality in growth of bulk ternary InxGa1-xAs. Here, the optical and electrical properties of samples grown through the vertical Bridgman (or multi-component zone melting growth) method have been investigated through photoluminescence spectroscopy and Hall effect measurements. Indium mole fractions varied from 0.75 for 1. Hall effect measurements at temperatures ranging from 10 to 300 K revealed moderate n-type doping with carrier concentrations ranging from 1.5 to 9.6×1016 cm-3 at 10 to 15 K. Carriers from deep donor levels became appreciable between 50 and 100 K. Hall …
Time-Temperature Curing Relationship Of An Adhesive Binder With Rice Straw,
2010
California Polytechnic State University, San Luis Obispo
Time-Temperature Curing Relationship Of An Adhesive Binder With Rice Straw, Kevin Ka-Wan Ng
Master's Theses
Rice straw is a global and proliferate agricultural waste whose production grossly outstrips viable uses. Current disposal methods are not sustainable, and more convenient methods – such as incineration – exude poor environmental stewardship. Although the direct use of straw bales in building construction presents a practical and sustainable alternative, engineering challenges associated with using it prevent its wide adoption. The Stak Block – a composite formed from compressed rice straw and a heat-cured adhesive – may overcome challenges associated with straw bale building. However, the times and temperatures needed to cure the binder with straw are not well understood. …
[Ni(Tmen)(Acac)][B(Ph)4] A Probe For The Anion Basicity Of Ionic Liquids,
2010
Iowa State University
[Ni(Tmen)(Acac)][B(Ph)4] A Probe For The Anion Basicity Of Ionic Liquids, Joanna Bartosik, Anja V. Mudring
Anja V. Mudring
An optical basicity scale of various ionic liquids (IL) anions has been determined by UV-Vis absorption spectroscopy. The indicator complex [Ni(tmen)(acac)][B(Ph)4] (tmen = tetramethylethylendiamine, acac = acetylacetonate) shows to be a sensitive probe as the position of the 3A2g(F) → 3T1g(F) absorption maximum of square planar to octahedral Ni2+ shifts distinctly depending on the electron donor ability of the respective ionic liquid anion. If the Lewis basicity of the anion becomes stronger a change to a tetrahedral coordination around Ni2+ is observed. Here the 3T1(F) → 3T2(F) and 3T1(F) → 3T1(P) transitions are helpful for monitoring the IL anion basicity. …
On The Dissolution Of Non-Metallic Solid Elements (Sulfur, Selenium, Tellurium And Phosphorus) In Ionic Liquids,
2010
Iowa State University
On The Dissolution Of Non-Metallic Solid Elements (Sulfur, Selenium, Tellurium And Phosphorus) In Ionic Liquids, Eva Boros, Martyn J. Earle, Manuela A. Gilea, Andreas Metlen, Anja V. Mudring, Franziska Rieger, Allan J. Robertson, Kenneth R. Seddon, Alina A. Tomaszowska, Lev Trusov, Joseph S. Vyle
Anja V. Mudring
Ionic liquids are shown to be good solvents for elemental sulfur, selenium, phosphorus and tellurium, and can be designed to maximise the solubility of these elements. The presence of the [S3]˙− radical anion in diluted solutions of sulfur in some ionic liquids has been confirmed, and is the origin of their intense blue colour (cf. lapis lazuli).
Communication Prev. Article Next Article Table Of Contents Chains Of Face-Sharing {Zpr6} Octahedra With Alternating Endohedral Iridium Atoms And Chloride Ions In {(Ir,Cl)Pr6}Cl10,
2010
Iowa State University
Communication Prev. Article Next Article Table Of Contents Chains Of Face-Sharing {Zpr6} Octahedra With Alternating Endohedral Iridium Atoms And Chloride Ions In {(Ir,Cl)Pr6}Cl10, Nina Herzmann, Matthias Bruhmann, Anja V. Mudring, Gerd Meyer
Anja V. Mudring
The most impressive feature of the crystal structure of IrPr6Cl11 is chains of face-sharing {Pr6} octahedra that encapsulate, alternatingly, iridium atoms and chloride ions, according to the formulation {(Ir,Cl)Pr6}Cl10. An alternative description of the structure is the connection of isolated {IrPr6} clusters that are surrounded in a mixed {ZR6}Xi12/{ZR6}Xi8 type by chlorido ligands with a rather complex connectivity, {IrPr6}(Cli−a−a4/3Cla−i−a8/3Cli−a6/2Cla−i6/2)e(Cli−i2/2)f, to a three-dimensional structure of tetragonally packed cluster-complex chains.
Facile Preparation Of Quantum Cutting Gdf3 : Eu3+ Nanoparticles From Ionic Liquids,
2010
Iowa State University
Facile Preparation Of Quantum Cutting Gdf3 : Eu3+ Nanoparticles From Ionic Liquids, Chantal Lorbeer, Joanna Cybinska, Anja V. Mudring
Anja V. Mudring
Microwave reaction of Ln(OAc)3·xH2O, Ln = Gd, Eu; OAc = acetate) with and in the ionic liquid [C4mim][BF4] (C4mim = 1-butyl-3-methylimidazolium) allows the fast and efficient synthesis of small, uniform, oxygen-free lanthanide nanofluorides with excellent photophysical behaviour. For GdF3 : Eu3+ nanoparticles a quantum efficiency of up to 145% was determined.
Electronic And Magnetic Structure Of (Crcl 3 ) 3,
2010
Iowa State University
Electronic And Magnetic Structure Of (Crcl 3 ) 3, M. Grodzicki, B. Mallick, Anja V. Mudring
Anja V. Mudring
Electronic structure calculations in the local spin-density approximation have been carried out on the recently synthesized trimer (CrCl 3 ) 3 exhibiting antiferromagnetic ordering below T N =55 K. The calculated magnetic coupling constant, the paramagnetic Curie temperature, and the decrease of the magnetic moment below T N are well reproduced by the calculations. An interpretation of the spin structure is given that is consistent with all experimental data currently available.
Optical Basicity Of Ionic Liquids,
2010
Iowa State University
Optical Basicity Of Ionic Liquids, Slawomir Pitula, Anja V. Mudring
Anja V. Mudring
The concept of optical basicities initially developed by Duffy for solid oxides was successfully transferred to low melting salts such as ionic liquids (ILs). Several ionic liquids (ILs) were doped with Mn(NTf2)2 (NTf2 = bis(trifluoromethanesulfonyl)imide) as a probe to investigate the IL anion basicity by means of UV-Vis spectroscopy. The 6A1 → 4A, 4E(G) transition band of Mn2+ is influenced by the electron donor properties, i.e., Lewis basicity, of the coordinating ligands but remains—to the first order—independent from the ligand field. The change in the optical spectra for various Mn(NTf2)2 doped ILs is predominantly dependent on the anion. No significant …
Electrostatic Quadrupole Plasma Mass Spectrometer Measurements During Thin Film Depositions Using Simultaneous Matrix Assisted Pulsed Laser Evaporation And Magnetron Sputtering,
2010
Air Force Research Laboratory
Electrostatic Quadrupole Plasma Mass Spectrometer Measurements During Thin Film Depositions Using Simultaneous Matrix Assisted Pulsed Laser Evaporation And Magnetron Sputtering, Chad N. Hunter, Michael H. Check, Christopher Muratore, Andrey A. Voevodin
Chemical and Materials Engineering Faculty Publications
A hybrid plasma deposition process, combining matrix assisted pulsed laser evaporation (MAPLE) of carbon nanopearls (CNPs) with magnetron sputtering of gold was investigated for growth of composite films, where 100 nm sized CNPs were encapsulated into a gold matrix. Composition and morphology of such composite films was characterized with x-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy (TEM) analysis. Carbondeposits on a gold magnetron sputter target and carbon impurities in the gold matrices of depositedfilms were observed while codepositing from gold and frozen toluene-CNP MAPLE targets in pure argon. Electrostatic quadrupole plasma analysis was used to determine that …
