Influence of Porosity on Fracture Toughness of Hydroxyapatite/Multi-Walled Carbon Nanotubes Biocomposite Materials

Russian Physics Journal - The paper analyzes the influence of porosity of hydroxyapatite (HA)/multi-wall carbon nanotubes (MWCNTs) composites on their fracture toughness. It is found that two...     

Synthesis of polymer nanocomposite ion-exchange membranes from sulfonated polystyrene and study of their properties

Methods for the preparation of composite ion-exchange membranes from polymer (polyvinylidene fluoride (PVDF), ultrahigh molecular weight polyethylene (UHMWPE), and polypropylene (PP)) matrices were considered. Polystyrene (PS) was introduced in the matrices by thermal polymerization of the monomer followed by sulfonation of the implant. The fundamentals of membrane synthesis from industrial polytetrafluoroethylene (PTFE, Teflon F-4) films by thermal polymerization of styrene in a film stretched in a monomer solution followed by sulfonation of incorporated PS were described. The literature on radiation- chemical synthesis of composite ion-exchange membranes based on polymer matrices with embedded polystyrene and its subsequent sulfonation was analyzed. Some problems of the kinetics and mechanism of thermal implantation of PS into various polymer matrices under different conditions were discussed. The physicochemical characteristics, structure, and transport properties of the membranes synthesized by thermal implantation of PS were reported. The obtained membranes were tested in low-temperature fuel cells.     

Formation of benzenediols upon electron-beam distillation of lignin mixtures with alkanes

In the process of the electron-beam distillation of lignin, its conversion into benzenediols increases in the presence of alkanes in the irradiated sample. An increase in the yield of benzenediols is accompanied by a decrease in the fractions of guaiacol, creosol, ethylguaiacol, and vinylguaiacol in the tar distilled off. It has been noted that alkanes serve as an additional source of atomic hydrogen and alkyl radicals, which, in turn, play a key role in the formation of benzenediols. In the presence of alkanes in the irradiated sample, guaiacol can be the main precursor of catechols; the proportion of guaiacol in the tar is almost three times below that in the case of distillation of individual lignin. It has been hypothesized that the chain decomposition of lignin can occur with the participation of ?H and ?CH₃ radicals.     

Features of the Invariant Correlation Filter Application for Recognition of Color Subpixel Images

Radiophysics and Quantum Electronics - We present the results of simulation of image recognition using invariant correlation filters. The possibilities of exploiting color information and...     

Thermal Polymerization of Styrene Sorbed from the Gas Phase into Polymer Films as a Method for Synthesizing Precursors of Ion-Exchange Membranes

Russian Journal of Electrochemistry - Abstract—The thermal polymerization of styrene sorbed from the gas-phase into polymer films of polyvinylidene fluoride (PVDF) is carried out at...     

Design of monomeric units for rigid aromatic polymers

Structural Chemistry - The effect of structural inhomogeneities on the equilibrium flexibility of rigid-chain aromatic polymers containing complex condensed cycles in the main chain has been...     

Prospects for applications of electron beams in processing of gas and oil hydrocarbons

Physics of Atomic Nuclei - Waste-free processing of oil and oil gases can be based on electron-beam technologies. Their major advantage is an opportunity of controlled manufacturing of a wide range...     

Electron beam-assisted cracking of synthetic paraffins

The electron beam-initiated cracking of a mixture of C₁₇–C₁₂₀ paraffins at 350–370°C has been studied. The cracking regime implied simultaneous feedstock irradiation and rapid distillation of fragmentation products from the irradiation zone. The distillate was a mixture of 61.5 wt % alkanes and 38.5 wt % alkenes. The product molecule contained on average 13 carbon atoms. The gasoline fraction in the condensate was 32.3 wt %. It was demonstrated that the product composition can be changed depending on the geometric parameters of reaction equipment and temperature distribution at the reactor outlet.