Open Access. Powered by Scholars. Published by Universities.®

Other Materials Science and Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

Selected Works

2011

Discipline
Institution
Keyword
Publication
File Type

Articles 1 - 22 of 22

Full-Text Articles in Other Materials Science and Engineering

Optimization Of The Acoustic Performance Of Polyimide Foams, Olivier Doutres, Noureddine Atalla, Rebecca Wulliman, Shari Ferguson, Steve Bailey Jul 2011

Optimization Of The Acoustic Performance Of Polyimide Foams, Olivier Doutres, Noureddine Atalla, Rebecca Wulliman, Shari Ferguson, Steve Bailey

Olivier Doutres Ph.D.

Due to their low weight, high fire resistance and good mechanical strength, SOLIMIDE® Polyimide foams are good candidates for sound packages in aerospace sound transmission applications. However, their high resistance to airflow limits the sound absorption efficiency inside a double wall structure and thus the sound transmission loss of the structure. The paper discusses two concepts to improve the transmission efficiency of such materials for double wall applications: (i) improving its sound absorption behavior by removing mechanically or chemically the cell membranes and thus decreasing both the flow resistance and tortuosity, (ii) coupling the Polyimide foams to screens (porous or …

Go to article

A Practical Impedance Tube Method To Estimate The Normal Incidence Sound Transmission Loss Of Double Wall Structure, Olivier Doutres, Noureddine Atalla Jul 2011

A Practical Impedance Tube Method To Estimate The Normal Incidence Sound Transmission Loss Of Double Wall Structure, Olivier Doutres, Noureddine Atalla

Olivier Doutres Ph.D.

The objective of this paper is to propose a practical impedance tube method to optimize the sound transmission loss of double wall structure by concentrating on the sound package placed inside the structure. In a previous work, the authors derived an expression that breaks down the transmission loss of a double wall structure containing a sound absorbing blanket separated from the panels by air layers in terms of three main contributions; (i) sound transmission loss of the panels, (ii) sound transmission loss of the blanket and (iii) sound absorption due to multiple reflections inside the cavity. The sound transmission loss …

Go to article

Transferts De Chaleur Dans Un Réacteur Thermochimique Solaire Muni D’Un Récepteur Volumique Poreux, Hernando Romero Paredes Rubio May 2011

Transferts De Chaleur Dans Un Réacteur Thermochimique Solaire Muni D’Un Récepteur Volumique Poreux, Hernando Romero Paredes Rubio

Hernando Romero Paredes Rubio

Un réacteur thermochimique solaire de 1 kW muni d’une structure céramique poreuse en céramique est modélisé pour simuler les transferts thermiques a l’intérieur du récepteur volumétrique. Le modèle développé a été utilisé pour prévoir le comportement thermique du réacteur en fonction des différentes conditions opératoires qui concernent le débit de gaz inerte, le flux solaire incident, la porosité, la longueur du récepteur, et la prise en compte de réactions chimiques. Les résultats montrent que la température maximale est de 1850K pour une concentration solaire de 1000 soleils. La température diminue de manière significative lorsque le débit de gaz augmente. Un …

Go to article

Cryogenic Technique For Processing Steel Treatment, Ajit Behera Jan 2011

Cryogenic Technique For Processing Steel Treatment, Ajit Behera

Ajit Behera

Cryogenics or deep freezing have been around for quite some time. There is documented research from as far back as the 1930’s where German companies used it on components of jumbo aircraft engines. Cryogenic processing had its US origins in the 1940s. Cold treatments or sub zero treatments are done to make sure there is no retained austenite during quenching. Cryogenics is a relatively new process and to eliminate retained austenite, the temperature has to be lowered, but one that using correct procedures can bring substantial economic benefits. In cryogenic treatment the material is to be deep freeze temperatures of …

Go to article

Demand On Magic Metal, Ajit Behera Jan 2011

Demand On Magic Metal, Ajit Behera

Ajit Behera

No abstract provided.

Go to article

Preparation And Characterisation Of Graft Biopolymer To Improve Sustained Release Property, Ajit Behera Jan 2011

Preparation And Characterisation Of Graft Biopolymer To Improve Sustained Release Property, Ajit Behera

Ajit Behera

In the present piece of research work focuses on grafting Acrylic acid with HPMC to obtain copolymers with improved properties, biodegradable and biocompatible that will be used as hydrogel or water absorbing polymers. To develop a prolong release activity drug delivery system for the medication purpose to enhance drug activity and reduce the frequency of dose via this hydrogel. A novel HPMC-g- acrylic acid hydrogel was prepared by in-situ emulsifier free emulsion polymerization using benzyl peroxide as an initiator through 1-stage grafting. Acrylic Acid could intercalate into layers of HPMC and form graft composites through in situ graftpolymerization with acrylic …

Go to article

The Natural Composite: Spheroidal Graphite Iron, Ajit Behera Jan 2011

The Natural Composite: Spheroidal Graphite Iron, Ajit Behera

Ajit Behera

The conventional materials are nowadays not sufficient to cater to the variety of uses and exposure to various environments that may take place while they are put into use. Hence this leads to the development of composites, which nearly suffice the above two conditions. Composite material is a material composed of two or more distinct phases (matrix phase and reinforcing phase) and having bulk properties significantly different from those of any of the constituents. In this developing age for iron industry there is large demand for spherodial Graphite iron (S.G. Iron). S.G. Iron also known as a composite in which …

Go to article

Characterisation Of Nanoparticle Through Sem, Ftir, Xrd & Dsc, Ajit Behera Jan 2011

Characterisation Of Nanoparticle Through Sem, Ftir, Xrd & Dsc, Ajit Behera

Ajit Behera

Nanoparticles are widely due as Sustained Release Drug Delivery System. Due to their smaller size of controlled drug release potential, targeting ability, enhancement of therapeutic efficacy and reduction of toxicity. Nifedipine one of the calcium channel blocker use for the management of hypertension. Spray drier technique develops Nifedipine loaded nanoparticle. Primary superimulsion phase contains Drug (Nifedipine), Polymer (Ethylcellulose) & suitable non-aqueous Solvent (Dichloromethane) which are sprayed over secondary phase containing aqueous solvent with dispersing polymers (PVA) are prepared by taking drug to polymer weight ratio of 20:90. Formation of films on the surface of secondary phase dried, sieved & forward …

Go to article

New Trend Of Metal Coating In Aerospace Component, Ajit Behera Jan 2011

New Trend Of Metal Coating In Aerospace Component, Ajit Behera

Ajit Behera

No abstract provided.

Go to article

Metallurgical Changes In Steels By Cryogenic Processing, Ajit Behera Jan 2011

Metallurgical Changes In Steels By Cryogenic Processing, Ajit Behera

Ajit Behera

No abstract provided.

Go to article

Efficiency Of Ionic Liquids In The Dissolution Of Rice Husk, Teck Nam Ang Dr., Li Wan Yoon Ms., Kiat Moon Lee Ms., Gek Cheng Ngoh Dr., Adeline Seak May Chua Dr., Min Gyu Lee Prof. Jan 2011

Efficiency Of Ionic Liquids In The Dissolution Of Rice Husk, Teck Nam Ang Dr., Li Wan Yoon Ms., Kiat Moon Lee Ms., Gek Cheng Ngoh Dr., Adeline Seak May Chua Dr., Min Gyu Lee Prof.

Teck Nam Ang Dr.

Ionic liquids that dissolve cellulose provide an option to pretreat lignocellulosic biomass. In this study, potential application of three ionic liquids in pretreating rice husk and their abilities in dissolving rice husk cellulose were investigated. The ionic liquids applied were 1-butyl-3- methylimidazolium chloride ([BMIM]Cl), 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc), and 1-ethyl-3-methylimidazolium diethyl phosphate ([EMIM]DEP). Dissolution of rice husk was conducted by heating 1.5% (w/v) rice husk-ionic liquid mixture at 100oC for 20 hours. The dissolved cellulose was subsequently regenerated with deionised water. All the ionic liquids were able to dissolve rice husk cellulose to varying extents, with the highest dissolution (36.7%) given …

Go to article

Ionic Liquids As Crystallization Media: Weakly-Coordinating Anions Do Coordinate In 1∞[Eu(Otf)3(Ch3cn)3], Sifu Tang, Anja V. Mudring Jan 2011

Ionic Liquids As Crystallization Media: Weakly-Coordinating Anions Do Coordinate In 1∞[Eu(Otf)3(Ch3cn)3], Sifu Tang, Anja V. Mudring

Anja V. Mudring

Tris(acetonitrile)tris(trifluoromethanesulfonato)-europium(III), 1∞[Eu(OTf)3(CH3CN)3], is the first structurally characterized Ln(OTf)3-solvate where triflate is still in the coordination sphere of the Ln(III) cation and not substituted by solvate molecules. This fact is attributed to the unique crystallization conditions that an ionic liquid provides: 1∞[Eu(OTf)3(CH3CN)3] was obtained from a solution of europium(III) triflate, Eu(OTf)3, with acetonitrile in the ionic liquid [C4py][OTf] (1-butylpyridinium triflate). The crystal structure (triclinic, P1̅ (no. 2), a = 5.734(1) Å, b = 10.500(2) Å, c = 19.088(4) Å, α = 98.09(3)°, β = 93.79(3)°, γ = 91.46(3)°, V = 1134.5(4) Å3, Z = 2, R1 for 4388 reflections with Io …

Go to article

Efficient Quantum Cutting In Hexagonal Nagdf4:Eu3+ Nanorods, Pushpal Ghosh, Sifu Tang, Anja V. Mudring Jan 2011

Efficient Quantum Cutting In Hexagonal Nagdf4:Eu3+ Nanorods, Pushpal Ghosh, Sifu Tang, Anja V. Mudring

Anja V. Mudring

An ionic liquid (IL) assisted solvothermal method is employed to prepare single phase, oxygen free, hexagonal NaGdF4:Eu3+ (2 mol%) nanorods with a visible quantum efficiency of 187%. In contrast, for mixed materials containing cubic and hexagonal NaGdF4:Eu3+, the quantum efficiency is much less (127%). Thus, synthesis parameters have to be carefully chosen in order to get the high performance hexagonal material. Not only the influence of the IL but also of the Gd : F ratio during synthesis as well as the temperature were studied. It is found that the IL stabilizes the formation of hexagonal NaGdF4:Eu3+, likewise a fluoride …

Go to article

Stability And Growth Behavior Of Transition Metal Nanoparticles In Ionic Liquids Prepared By Thermal Evaporation: How Stable Are They Really?, Kai Richter, Alexander Birkner, Anja V. Mudring Jan 2011

Stability And Growth Behavior Of Transition Metal Nanoparticles In Ionic Liquids Prepared By Thermal Evaporation: How Stable Are They Really?, Kai Richter, Alexander Birkner, Anja V. Mudring

Anja V. Mudring

Recently we developed an access to metal- and metal-oxide colloids based on thermal evaporation of metals into ionic liquids (ILs). Here we present systematic studies on the long-time stability of gold and copper nanoparticles (NPs) in different ILs. The influence of metal concentration and temperature on the ripening of the as-prepared gold NPs in different ILs was investigated by transmission electron microscopy (TEM) and UV-vis absorption measurements. Short alkyl chain-length-methyl-imidazolium salts with weakly coordinating perfluorinated counter anions (PF6, BF4 or Tf2N, bis(trifluoromethanesulfonyl)amide) were found to be better stabilizers compared to ILs with cations bearing long alkyl chains (trihexyltetradecylphosphonium, 1-octyl-3-methylimidazolium) and …

Go to article

Structures, Electronic Properties And Solid State Luminescence Of Cu(I) Iodide Complexes With 2,9-Dimethyl-1,10-Phenanthroline And Aliphatic Aminomethylphosphines Or Triphenylphosphine, Radoslaw Starosta, Malgorzata Puchalska, Joanna Cybinska, Maciej Barys, Anja V. Mudring Jan 2011

Structures, Electronic Properties And Solid State Luminescence Of Cu(I) Iodide Complexes With 2,9-Dimethyl-1,10-Phenanthroline And Aliphatic Aminomethylphosphines Or Triphenylphosphine, Radoslaw Starosta, Malgorzata Puchalska, Joanna Cybinska, Maciej Barys, Anja V. Mudring

Anja V. Mudring

The luminescent complexes of triphenylphosphine and two interesting aminomethylphosphines: P(CH2N(CH2CH2)2NCH3)3 and P(CH2N(CH2CH2)2O)3 with copper(I) iodide and 2,9-dimethyl-1,10-phenanthroline (dmp): [CuI(dmp)PPh3], [CuI(dmp)P(CH2N(CH2CH2)2NCH3)3] and [CuI(phen)P(CH2N(CH2CH2)2O)3] are presented in this work. These complexes were characterized in solution by means of NMR spectroscopy and their structures were crystallographically determined in the solid state. All complexes crystallize as the discrete dimers bound by π-stacking interactions between dmp rings. The coordination geometry about the Cu(I) centre is pseudo-tetrahedral showing small flattening and large rocking distortions. The investigated compounds exhibit intense orange photoluminescence in the solid state (emission peaks at r.t.: λmax = 588–592 nm; τ = 1.7–2.2 …

Go to article

In-Situ Crystal Growth And Properties Of The Magnetic Ionic Liquid [C2mim][Fecl4], Tobias Backer, Oliver Breunig, Klaus Merz, Vera Vasylyeva, Anja V. Mudring Jan 2011

In-Situ Crystal Growth And Properties Of The Magnetic Ionic Liquid [C2mim][Fecl4], Tobias Backer, Oliver Breunig, Klaus Merz, Vera Vasylyeva, Anja V. Mudring

Anja V. Mudring

[C2mim][FeCl4] behaves like a paramagnetic liquid at room temperature. Specific heat measurements indicate that there is a magnetic ordering below 3.8 K. The released entropy is far from the expected value for a J = 5/2 system, implying that the magnetic state is partly disordered. Full magnetic polarization was reached in fields above 4 T, and the anomaly in the magnetic susceptibility can be fully suppressed in higher B fields. Hence, the suggested magnetic ground state is superparamagnetic. In order to better understand the magnetic nature of this compound, structural investigations were carried out. Raman and IR-spectroscopy as well as …

Go to article

A New Open-Framework Iron Borophosphate From Ionic Liquids: Kfe[Bp2o8(Oh)], Guangmei Wang, Anja V. Mudring Jan 2011

A New Open-Framework Iron Borophosphate From Ionic Liquids: Kfe[Bp2o8(Oh)], Guangmei Wang, Anja V. Mudring

Anja V. Mudring

A new open-framework iron borophosphate, KFe[BP2O8(OH)], has been obtained by ionothermal synthesis from KH2PO4, FeCl3∙4H2O, H3BO3 and [C4mpyr]Br (1-butyl-1-methylpyrrolidinium bromide). Single-crystal X-ray diffraction analysis shows that KFe[BP2O8(OH)] (monoclinic, P21/c, a = 9.372(2) Å , b = 8.146(2)Å , c = 9.587(2) Å, β = 101.18(3)°, V = 718.0(2)Å3 and Z = 4) has a three-dimensional (3-D) framework structure composed by {Fe(III)O5(OH)} octahedra as well as {BO3(OH)} and {PO4} tetrahedra. As anionic structural sub-unit, KFe[BP2O8(OH)], contains an infinite open-branched {[BP2O8(OH)]4-} chain which is formed by alternating {BO3(OH)} and {PO4} tetrahedra. {Fe(III)O5(OH)} octahedra share common O corners with five phosphate tetrahedra and …

Go to article

The First Lanthanide Telluride-Bromide: La3te4br, A Valence Compound, Markus Larres, Anja V. Mudring, Gerd Meyer Jan 2011

The First Lanthanide Telluride-Bromide: La3te4br, A Valence Compound, Markus Larres, Anja V. Mudring, Gerd Meyer

Anja V. Mudring

The first ternary lanthanide telluride-bromide La3Te4Br was obtained from a mixture of LaTe and LaBr3 (in the presence of iridium) in a sealed tantalum container at elevated temperatures. The crystal structure (orthorhombic, Pnma, a = 1634.3(2), b = 435.0(1), c = 1426.6(2) pm, Z = 4, R1 (I0 > 2s(I0)) = 0.0349) is built from dicapped trigonal prisms of tellurium and bromine atoms surrounding lanthanum in two different ways. The dicapped trigonal prisms are connected via common edges to a threedimensional structure, in the same fashion as is known for the binary U3Te5. La3Te4Br is a valence compound according to (La3+)3(Te2-)4(Br-) …

Go to article

Linear Trimeric Hafnium Clusters In Hf0.86(1)I3, Jan Beekhuizen, Anja V. Mudring, Gerd Meyer Jan 2011

Linear Trimeric Hafnium Clusters In Hf0.86(1)I3, Jan Beekhuizen, Anja V. Mudring, Gerd Meyer

Anja V. Mudring

The reduction of hafnium tetraiodide, HfI4, with aluminum at 600 °C or 850 °C in the presence of a NaI flux resulted in black single crystals of Hf0.86(1)I3. This composition corresponds well to the upper end of the non-stoichiometry range 0.89 ≤ x ≤ 1.00 previously reported for HfxI3. The crystal structure (a = 1250.3(2), c = 1999.6(3) pm, R-3m, Z = 18) is made up of hexagonal closest packed layers of iodide ions. One third of the octahedral holes would be filled as in TiI3 or ZrI3 if it were Hf1.00I3. In Hf0.86(1)I3, one out of six octahedral holes …

Go to article

(B15c5)Bii3(I2): Molecular Benzo-15-Crown-5―Bii3 Complexes Bridged By Iodine Molecules To Chains, Christoph Fiolka, Mark Richter, Ingo Pantenburg, Anja V. Mudring, Gerd Meyer Jan 2011

(B15c5)Bii3(I2): Molecular Benzo-15-Crown-5―Bii3 Complexes Bridged By Iodine Molecules To Chains, Christoph Fiolka, Mark Richter, Ingo Pantenburg, Anja V. Mudring, Gerd Meyer

Anja V. Mudring

The reaction of bismuth triiodide with iodine and benzo-15-crown-5 in ethanol/dichloromethane yielded red single crystals of (b15c5)BiI3(I2) (monoclinic, P21/c (no. 14), a = 1376.9(1), b = 1172.7(1), c = 1700.2(2) pm, b = 115.197(6), V = 2484.1(4)·106 pm3, Z = 4). Neutral pseudo-octahedral complexes (b15c5)BiI3 are connected by secondary bonding interactions via iodine molecules to chains. Electronic structure calculations of the neutral complex (b15c5)BiI3 reveal that the compound can indeed be described as b15c5 interacting with a molecular BiI3 unit. However, bonding has to be mainly electrostatic as the interactions of the bismuth 6s lone pair with the 2p orbitals …

Go to article

Europium(Iii) Fluoride Nanoparticles From Ionic Liquids: Structural, Morphological, And Luminescent Properties, Chantal Lorbeer, Joanna Cybinska, Anja V. Mudring Jan 2011

Europium(Iii) Fluoride Nanoparticles From Ionic Liquids: Structural, Morphological, And Luminescent Properties, Chantal Lorbeer, Joanna Cybinska, Anja V. Mudring

Anja V. Mudring

Inorganic luminescent materials (phosphors) find widespread scientific and industrial applications. For potential applications, nanoscale phosphors are favored because of the reduced scattering and the possibility to miniaturize devices. In such materials, the optical behavior is strongly dependent on impurities or defects in the crystal lattice, so that a well-defined reaction protocol with fixed parameters is compulsory to ensure the quality of the obtained material. The fast and facile conversion of europium acetate via microwave radiation with and in different tetrafluoroborate ionic liquids to oxygen-free, hexagonal EuF3 nanoparticles is investigated in detail. The study of the influence of the different reaction …

Go to article

Reverse Logic - Safety Of Spent Nuclear Fuel Disposal, Antti Lempinen, Marianne Silvan-Lempinen Dec 2010

Reverse Logic - Safety Of Spent Nuclear Fuel Disposal, Antti Lempinen, Marianne Silvan-Lempinen

Antti Lempinen

No abstract provided.

Go to article