Physico-chemical and Thermal Characteristics of Lime-silica Fume Pastes

Five lime-silica fume pastes were investigated using initial CaO/SiO₂ molar ratios of 0.80, 1.0, 1.30, 1.70 and 2.0. The kinetics and mechanism of hydration interaction between lime and silica fume were studied on the basis of the phase composition and the physical state of the formed hydration products. The developed strength could be related to the lime content of the lime-silica mixture and the formed hydrates. This revised version was published online in August 2006 with corrections to the Cover Date.     

Interfacial Interactions and Properties of Polyethylene‐Layered Silicate Nanocomposites

Summary: Organically modified montmorillonites (OMs), carrying alkyl chains, phenyl groups, or a combination of both, were prepared and compounded with polyethylene. The oxygen permeability coefficients and tensile properties of the nanocomposites were correlated to the exfoliation of the OMs. Partial exfoliation was achieved, although no intercalation was observed. Aromatic moieties attached to the clay surface led to a stronger interaction between the OM layers and less exfoliation.

Transmission electron micrograph of a 2.8 vol.‐% dioctadecyldimethylammonium nanocomposite. The dark lines are cross sections of aluminosilicate layers.     

Electronic structure of 4H-pyrido[1,2-a]pyrimidin-4-ones

The characteristic features of ir and uv spectra of 43 4H-pyrido[1,2-a]pyrimidin-4-one derivatives with electron donor or acceptor groups in position 3, and positions 6, 7, 8, or 9, respectively, have been systematically studied. On the basis of the spectra some conclusions have been drawn for the molecular structure. The negative solvent effect of the lowest-energy π → π* transition is investigated by the PPP method.     

Characterization of the barrier parameter of homogeneous convex cones

We characterize the smallest (best) barrier parameter of self-concordant barriers for homogeneous convex cones. In particular, we prove that this parameter is the same as the rank of the cone which is the number of steps in a recursive construction of the cone (Siegel domain construction). We also provide lower bounds on the barrier parameter in terms of the Carathéodory number of the cone. The bounds are tight for homogeneous self-dual cones. © 1998 The Mathematical Programming Society, Inc. Published by Elsevier Science B.V.Research supported in part by an operating grant from NSERC of Canada.Research supported in part by the National Science Foundation under grant DMS-9306318.     

Polymerization of monoisocyanates by the Pruitt–Baggett adduct

n-Butyl isocyanate (nBIC) was polymerized in bulk by the Pruitt–Baggett adduct (PBA) at ?23, 0.0, and 25.0°C. Polymerization was accompanied by trimerization to the cyclicisocyanurates at all temperatures. Spectroscopic evidences supported the nylon-1 structure for both trimer and polymer. The polymer/trimer ratio and the molecular weight of produced polymers were found to increase with decreasing temperature. The Pruitt–Baggett catalyst (PBC), which is the reaction product of (PBA + H₂O) system, also polymerized nBIC, but with a relatively slower rate. In aromatic and etheric solutions, nBIC was only trimerized by PBA. Copolymerization of nBIC with propylene oxide by PBA and PBC failed. Some selected monoisocyanates were also polymerized by PBA. © 1993 John Wiley & Sons, Inc.     

Shear viscosity of hydrogen and helium fluids at extended regions of temperatures and pressures

Shear viscosities of hydrogen (H₂) and helium (He) fluids are investigated at extended regions of temperature and pressure using an improved equation of state, in which the the long-range attractive forces are incorporated into the formalism via the double Yukawa (DY) potential fitted to the empirical H₂ and He potentials. Quantum effects, which become paramount at low temperatures, are taken into account through a first-order quantum correction based on the Wigner–kirkwood expansion. The dimerization of H₂ is treated as a hard convex body for which an equation of state can be derived based on the scaled particle theory.     

Complexes of N-(2 Hydroxy-1-Naphthalidene) Antharanilic Acid with Some Lanthanides

The complexes of N-(2-hydroxy-1-naphthalidene)anthranilic acid abbreviated (H₂NA) with some trivalent rare earth elements (Pr, Nd, Sm, Gd, Dy, Er and Yb) were prepared. The complexes were characterized by chemical and thermal analysis, ir and conductimetric methods. Two types of ionic complexes; Ln(HNA)₂OH·2H₂O with Dy, Er and Yb, and Ln(HNA)₂OH with Pr, Nd, Sm and Gd were isolated. Coordination of the ligand with metal-ions occurs through the carboxy group and the nitrogen atom. The acid dissociation constants K₁ and K₂ of H₂NA and the overall stability constants β₁ and β₂ of some lanthanide complexes in 75% (v/v) dioxan-water solutions were determined by the potentiometric method.     

Evaluation of infection imaging potential of <Superscript>131</Superscript>I-labeled imidazolium salt

Effective antimicrobial compounds are necessary due to increased resistance of antibiotics against microorganisms causing infectious diseases. In this study, imidazolium-TFSI salt [ITFSI: octyl-bis(3-methylimidazolium)-di(bis(trifluoromethane)sulfonimide)] was labeled with ¹³¹I with high efficiency. In vitro uptake experiments of ¹³¹I-ITFSI showed high uptake in gram-positive Staphylococcus aureus bacteria. ¹³¹I-ITFSI was also evaluated for comparison between bacterial infection and sterile inflammation by in vivo studies. The biodistribution results revealed that ¹³¹I-ITFSI might be used as a nuclear imaging agent for detection of bacterial infection.