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2nd Workshop on Inverse Problems in Rheology and Related Experimental Techniques

Numerical and Analytical Methods in Non-Newtonian Fluid Mechanics

Influence of the elastomeric polypropylene addition on the properties of commercial metallocenic polypropylene

Polypropylene with special properties can be obtained by metallocenic catalysts. These catalytic systems represent the beginning of a new age in polyolefins technology. In this work, the influence of the addition of a syndiotactic polypropylene (s-PP) on the processability and mechanical properties of a commercial iso…

Influence of the radial spacing between cathodes on the surface composition of iron samples sintered by hollow cathode electric discharge

The present work reports an investigation of the influence of the radial spacing between cathodes on the iron sintering process by hollow cathode electrical discharge, with surface enrichment of the alloying elements Cr and Ni. Pressed cylindrical samples of 9.5 mm diameter and density of 7.0 ± 0.1 g/cm³ were prepared…

475 °C Embrittlement in a duplex stainless steel UNS S31803

The susceptibility of a duplex stainless steel UNS S31803 to thermal embrittlement at 475 °C was evaluated by means of mechanical tests (impact energy and hardness), magnetic measurements (hysteresis and thermomagnetic analysis) and scanning electron microscopy. The results show that the material undergoes severe embr…

Unusual Ferromagnetic Couplings in Single End-to-End Azide-Bridged Cobalt(II) and Nickel(II) Chain Systems

Two new one-dimensional single azide-bridged metal(II) compounds [[M(5-methylpyrazole)4(N3)]n](ClO4)n(H2O)n [M = Co (1a), Ni (2a)] were prepared by treating an M(II) ion with stoichiometric amount of sodium azide in the presence of four equivalents of the 3(5)-methylpyrazole ligand. The isostructural compounds 1a and…

A New Application for Microgels: Novel Method for the Synthesis of Spherical Particles of the Y2O3:Eu Phosphor Using a Copolymer Microgel of NIPAM and Acrylic Acid

The preparation of spherical phosphor europium-doped yttrium oxide (Y 2 O 3:Eu) particles using a copolymer of N -isopropylacrylamide (NIPAM)] and acrylic acid (AAc) is described. The resulting phosphor particles have smaller particle diameters (<0.1 μm) compared to both commercial Y 2 O 3:Eu phosphors and spherical p…

Encapsulation of proteins by layer‐by‐layer adsorption of polyelectrolytes onto protein aggregates: Factors regulating the protein release

Abstract A novel method of protein encapsulation is proposed. Preformed protein aggregates are covered with polyelectrolyte layers by means of layer‐by‐layer adsorption. The polyelectrolyte membrane prevents protein leakage out of the capsule. Using chymotrypsin as a model enzyme the capsule wall selective permeabilit…

Superparamagnetic Triblock Copolymer/Fe2O3 Hybrid Nanofibers NSERC of Canada is acknowledged for sponsoring this research. Dr. R. Yamdagni and Ms. Q. Wu are thanked for help with the use of their NMR magnet. Dr. Zhao Li is thanked for performing the TGA analysis. G.L. thanks the NSF of China for a distinguished Young Investigator's grant.

Impregnating the cores of triblock-copolymer nanotubes with Fe2O3 renders them superparamagnetic. The resultant polymer/Fe2O3 hybrid nanofibers (see TEM image) have interesting properties in magnetic fields. The nanofibers align themselves in the magnetic-field direction, and mixtures of the nanofibers and nanotubes u…

Crystallization Behavior of Amorphous Silicon Carbonitride Ceramics Derived from Organometallic Precursors

The crystallization behavior of organometallic‐precursor‐derived amorphous Si‐C‐N ceramics was investigated under N 2 atmosphere using X‐ray diffractometry (XRD), transmission electron microscopy (TEM), and solid‐state 29 Si nuclear magnetic resonance (NMR) spectroscopy. Amorphous Si‐C‐N ceramics with a C/Si atomic ra…

Novel Silicon‐Boron‐Carbon‐Nitrogen Materials Thermally Stable up to 2200°C

Three novel Si‐C‐B‐N ceramic compositions, namely Si 2.9 B 1.0 C 14 N 2.9 , Si 3.9 B 1.0 C 11 N 3.2 and Si 5.3 B 1.0 C 19 N 3.4 , were synthesized using the polymer‐to‐ceramic transformation of the polyorganoborosilazanes [B(C 2 H 4 Si(Ph)NH) 3 ] n , [B(C 2 H 4 Si(CH 3 )NH) 2 –(C 2 H 4 Si(CH 3 )N(SiH 2 Ph))] n , and […

Mechanical Properties of Silicon Oxycarbide Ceramic Foams

The mechanical properties of ceramic foams obtained through a novel process that uses the direct foaming and pyrolysis of preceramic polymer/polyurethane solutions were investigated. The elastic modulus, flexural strength, and compressive strengths were obtained for foams in the as‐pyrolyzed condition; values up to 7.…

Effect of GGA on the half-metallicity of the itinerant ferromagnetCoS2

The half-metallicity of ${\mathrm{CoS}}_{2},$ important for its possible use in spintronic applications, is investigated by means of density functional full-potential linearized augmented plane wave calculations within both the local spin-density approximation (LSDA) and the generalized gradient approximation (GGA). I…

Micro‐/Macroporous Ceramics from Preceramic Precursors

Porous silicon oxycarbide (SiOC) ceramics in particular bulk and cellular structures are produced via polymer pyrolysis. By using optimal pyrolysis parameters (i.e., heating rate, maximum temperature) the addition of either solid fillers or chemically active additives is efficient in preventing the collapse of pore st…

Exchange-correlation effects in magnetic-field-induced superconductivity

Motivated by recent experiments on the organic superconductor $λ-(BETS)_2FeCl_4$ we study the Jaccarino-Peter effect (JPE), the earliest example of magnetic-field-induced superconductivity, from the point of view of current-density-functional theory. It is found that both Meissner (diamagnetic) and Pauli (paramagnetic…

Random manifolds in non-linear resistor networks: Applications to varistors and superconductors

We show that current localization in polycrystalline varistors occurs on paths which are, usually, in the universality class of the directed polymer in a random medium. We also show that in ceramic superconductors, voltage localizes on a surface which maps to an Ising domain wall. The emergence of these manifolds is e…

Spin currents and spin dynamics in time-dependent density-functional theory

We derive and analyse the equation of motion for the spin degrees of freedom within time-dependent spin-density-functional theory (TD-SDFT). Results are (i) a prescription for obtaining many-body corrections to the single-particle spin currents from the Kohn-Sham equation of TD-SDFT, (ii) the existence of an exchange-…

Suppression of Tunneling into Multiwall Carbon Nanotubes

We have studied tunneling of electrons into multiwall carbon nanotubes (NTs) in NT-gold and NT-NT junctions, the latter created by atomic force microscope manipulation. The tunneling conductance goes to zero as the energy (temperature and bias) is reduced, and the functional form is consistent with a power law. The ex…

Effect of Impurities on the Growth Kinetics of Crystals

This paper reviews the work made by the group of the present author on the effect of impurities on the kinetics of crystal growth in solutions. The impurity effect is here discussed in the light of the model proposed by Kubota and Mullin [J. Crystal Growth, 152 (1995) 86], in which impurities are assumed to be adsorbe…

Optical and electrical properties of direct-current magnetron sputtered ZnO:Al films

In this study, high-quality ZnO:Al (ZAO) films were prepared by using dc reaction magnetron sputtering technology. The effect of Al doped in ZnO films on electrical and optical properties and its scattering mechanism were discussed in detail. The results showed that Al2O3 could be effectively removed by controlling ox…