The growth of ambient aerosols in the conditions of the respiratory system

The effect on ambient aerosols of exposure to the conditions of the respiratory system was determined by sampling simultaneously through two dichotomous samplers in parallel. In one of the samplers the aerosol was brought to 37°C and near 100% relative humidity before passing through the virtual impactor. The results show that, as a result of humidification, about 10–15% by mass of the aerosol which would normally been collected in the fine (less than 2.5 μm aerodynamic diameter) fraction of the sample grows sufficiently when humidified to be collected with the coarse fraction. It is suggested that the direct application to inhalation studies of dichotomous sampler results should be approached with some caution.     

Unsaturated polyesters. II. Structure and properties of polyester resins based on cinnamylsuccinic acid

Unsaturated Polyester resins were prepared by the reaction of cinnamylsuccinic acid with saturated diols, namely, ethylene, diethylene, propylene, dipropylene, tetramethylene, and hexamethylene glycols, and the unsaturated diols, namely, 1,4-butene- and 1,4-butynediols. All the polyester resins obtained have been characterized and were found to cure with styrene, with relatively low conversions. The properties of the cured polyesters in the form of films were determined. IR and ¹H-NMR spectroscopy were used for both qualitative and quantitative analyses of the polyesters and their hydrolyzate products, after curing with styrene.     

Graft copolymerization onto rubber. VII. Graft copolymerization of methyl methacrylate onto rubber using potassium peroxydisulfate catalyzed by silver ion

The graft copolymerization of methyl methacrylate onto natural rubber (NR) was carried out varying the concentration of monomer, initiator, thiourea, and silver nitrate over a wide range. The grafting reaction was temperature-dependent. From the Arrhenius plot, the overall energy of activation was computed. A suitable reaction scheme and rate expression for the rate of polymerization was suggested.     

Fractoemission from Lead Zirconate-Titanate

We present measurements of the electron, positive ion, and photon emission accompanying the fracture in vacuum of poly-crystalline 95/5 lead zirconate-titanate. The intensities of the charged-particle components of this fractoemission are shown to depend strongly on the direction (relative to the direction of fracture) and magnitude of polarization. The most intense emission is observed when the fracture surfaces are perpendicular to the polarization direction. The emission intensity increases monotonically with polarization. These results are interpreted in terms of a model involving charge separation on the fracture surfaces leading to a microdischarge during fracture. Implications to the interpretation of triboluminesence effects are discussed.     

Experimental Procedure for Determining Transport Properties of Oxide Scales

To determine the transport properties of oxide scales growing on an alloy, a laboratory apparatus was developed which allows plotting of characteristic V = f (i) curves and oxidation with an applied electric field. The apparatus and formalism used are described; it appears that such experimental procedures allow determination of the mean ionic transport number, ti; the conductivity values σ, σ_i, and σ,_e; and the effective charge, Z*, of the moving species in the oxide scale (A1₂O₃ in the present case).     

Long-term transients in a reactor under forced concentration cycling

In the approach to a cycle-invariant state in the forced feed concentration cycling of the CO oxidation over a NiO catalyst, a very long transient has been observed lasting 80 ks or more. This transient appears to be associated only with CO pretreatment of the catalyst and is not a general phenomenon. The slow convergence to the cycle-invariant state reported in certain modelling calculations in the literature appears to have a different cause.     

Prediction of thermal comfort in a building during a cold spell

The comfort diagrams and the so-called PMV-PPD values are already used today directly and indirectly in a wide field in technical practice, even at a standard level. This theory is known also in Hungary, and the PMV-PPD values have been used by us for the solution of a design problem. The task was to elaborate a calculation method, an index number suitable for the determination of the thermal confort effect in the case of occasional underheating of residential and communal buildings in winter.The results of this work are presented in this paper.     

Preparation of vanadyl porphyrin complexes from a metal-porphyrin petroleum concentrate and study of their catalytic activity

A mixture of vanadyl porphyrin complexes was obtained from a metal-porphyrin concentrate (MPC) isolated from crude petroleum by selective extraction. The petroleum MPC was subjected to demetallization and the subsequent introduction of the vanadyl cation into the porphyrin ring. It was shown that the mixture of vanadyl-porphyrin complexes obtained from MPC catalyzes the cyclohexene epoxidation reaction. On the basis of experimental data, it was assumed that the mechanism of olefin oxygenation in the presence of vanadyl porphyrin complexes is similar to the mechanism of the Prilezhaev epoxidation reaction of unsaturated compounds.     

Nanolayered lightweight flexible shields with multidirectional optical transparency

New nanolayered coatings are designed and deposited on flexible plastic substrate having the thickness of 100 /spl mu/m, in order to realize lightweight ultrathin transparent shielding foils. The structure of the coating is optimized considering three figures of merit: the average transmittance in the visible range for normal incidence, the normalized average transmittance for oblique incidence at 550 nm, and the transmittance quality factor. The nanotechnology exploited for the deposition of the transparent metals is the dual ion beam sputtering. Tests of durability, optical transmission, and shielding effectiveness demonstrate that the film has a high adhesion under mechanical solicitation, high resistance against aging, peak transmittance in the visible range higher than 70%, omnidirectional properties in the range 0/spl deg/-60/spl deg/, and shielding effectiveness of 40 dB up to 6 GHz.