Mechanisms of antioxidant action: The role of nitroxyl radicals in the stabilization of PVC

Hindered amines and their derived oxidation products, the hindered nitroxyls and hydroxylamines are processing stabilizers and photoantioxidants for poly(vinyl chloride). The evidence suggests that oxidation of the amines occurs very rapidly and completely during mechanooxidation and that the resulting redox couple operates by a catalytic mechanism as described previously for hydrocarbon polymers.     

Sulfur content of crude rapesseed oil from aqueous extraction

Dry heating of rapeseed before grinding increased the sulphur content of the crude rapeseed oil. Boiling the seeds in H₂O before grinding caused a slight decrease in the sulphur level of the oil. Control of pH during boiling of the ground rapeseed increased the sulphur content of the oil from ca. 2 ppm at pH 3.1 to ca. 10 ppm at pH 7.6.     

Special features in dyeing modacrylic fibre

Conclusions The possibility of dyeing freshly-spun modacrylic fibre with cationic dyes and in bulk with dyes or pigments of various classes has been investigated under laboratory conditions.It is recommended to use dyeing of modacrylic fibre in bulk with acetone-soluble dyes, which permits one to eliminate the energy-intensive process of pigment dispersion.Translated from Khimicheskie Volokna, No. 6, p. 36, November–December, 1988.     

Preparation of a microporous composite: Encapsulation of paper by polyethylene

A rapid polymerization method for in situ synthesis of polyethylene in a typical paper matrix of cellulose fibers is described. The unique properties of this double matrix, polyethylene in cellulose, are the result of performing the polymerization in a nonsolvent such that simultaneous polymerization and crystallization takes place yielding a nascent morphology. The morphology has been studied by scanning electron microscopy and was found to be different from what is usually obtained for melt crystallized polyolefins. Optical microscopy shows the polyethylene to be present as a complementary matrix with respect to the basic fiber construct. Mechanical, optical, and other properties of encapsulated filter paper have been measured using standard TAPPI tests. The results show a general improvement in physical properties for a range of “add ons” from 0 to 27%. Wet-strength and opacity undergo major changes.     

Nature-Inspired Meta-Heuristics on Modern GPUs: State of the Art and Brief Survey of Selected Algorithms

Graphic processing units (GPUs) emerged recently as an exciting new hardware environment for a truly parallel implementation and execution of Nature and Bio-inspired Algorithms with excellent price-to-power ratio. In contrast to common multicore CPUs that contain up to tens of independent cores, the GPUs represent a massively parallel single-instruction multiple-data devices that can nowadays reach peak performance of hundreds and thousands of giga floating-point operations per second. Nature and Bio-inspired Algorithms implement parallel optimization strategies in which a single candidate solution, a group of candidate solutions (population), or multiple populations seek for optimal solution or set of solutions of given problem. Genetic algorithms (GA) constitute a family of traditional and very well-known nature-inspired populational meta-heuristic algorithms that have proved its usefulness on a plethora of tasks through the years. Differential evolution (DE) is another efficient populational meta-heuristic algorithm for real-parameter optimization. Particle swarm optimization (PSO) can be seen as nature-inspired multiagent method in which the interaction of simple independent agents yields intelligent collective behavior. Simulated annealing (SA) is global optimization algorithm which combines statistical mechanics and combinatorial optimization with inspiration in metallurgy. This survey provides a brief overview of the latest state-of-the-art research on the design, implementation, and applications of parallel GA, DE, PSO, and SA-based methods on the GPUs.     

Development of high‐definition aqueous polyvinylpyrrolidone photoresists for cathode ray tubes

Aqueous photoresists that are capable of higher resolutions than are currently employed by the cathode ray tube (CRT) industry were developed by combining photoactivators, which activate at shorter UV wavelengths with polyvinylpyrrolidone (PVP). Two photoactivators were synthesized: 4,4′‐diazido‐2,2′‐biphenyl disodium disulfonate (DABP), which has a maximum absorbance at 264 nm, and 4,4′‐diazido‐2,2′‐biphenylethane disodium disulfonate (DABPE), which has a maximum absorbance at 258 nm. The PVP/DABP and PVP/DABPE photoresists successfully imaged a pattern with resolution as small as 4.4 μm with photoactivator concentrations greater than 20% of the PVP concentration. Addition of silane and emulgen greatly improved the performance of the photoresists with more uniform coatings of thicknesses of up to 1.4 μm. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1637–1644, 2006     

Human interaction with policy flight simulators

Policy flight simulators are designed for the purpose of exploring alternative management policies at levels ranging from individual organizations to national strategy. This article focuses on how such simulators are developed and on the nature of how people interact with these simulators. These interactions almost always involve groups of people rather than individuals, often with different stakeholders in conflict about priorities and courses of action. The ways in which these interactions are framed and conducted are discussed, as well as the nature of typical results.     

Surface and subsurface products of the interaction of O2 with Ag under catalytic conditions

Polycrystalline Ag treated with O₂ at pressures up to 1 bar and at temperatures up to 920 K was examined by TDS. It was found that the peak commonly observed at 595±25 K and assigned to adsorbed atomic oxygen (O_a) is shifted to higher desorption temperatures with rising dosing temperatures. Since saturation of the uptake was not possible either, this peak was identified as dissolved atomic oxygen (O_d). The existence of a maximum for the O₂ uptake after exposure at 820 K was found. Hence, under conditions of formaldehyde synthesis ( 920 K) the ability of the catalyst to dissolve oxygen is near its maximum.     

Copper Complexes Obtained from the Schiff Base of Quinoline-2-Aldehyde and Aliphatic Diamines

Schiff base bis (2— quinolidene)- diamine gives a purple-red complex with copper ions with a λ_max at 530 mμ. The optimum pH for production of this complex is approximately 9.5. None of the metallic ions of the analytical groups II and III give rise to red complexes with the above Schiff base. Manganous (Mn²⁺) and stannous (Sn²⁺)ions as well as reducing agents such as hydrazine or hydroxylamine exert a catalytic effect on the rate of formation of these copper complexes. The thermal stability of the copper complex formed from the Schiff bases (2-quinoline-aldehyde with NH₂-(CH₂)_n-NH₂) is greater for diamine for which n = 4–6 than for n = 2–3.     

Non-markovian diffusion processes in polymers and a stretched exponential relaxation constitutive equation

Non-Markovian diffusion transport in polymers was studied. Applying the results of various researchers, a stretched exponential relaxation function was obtained and a linear viscoelastic constitutive equation formulated. Frequency dependent material functions, obtained from this constitutive equation were studied and the results successfully compared with experimental data for polyethylene oxide solutions. Sorption kinetics in a polymeric film were also studied. © 1994 John Wiley & Sons, Inc.