Replacement of Solid Chrome Plating with Boride Composite Coatings Based on Nickel and Iron

The feasibility of replacing solid chrome plating with a composite electrolytic coating based on Ni and Fe is discussed. The physical and mechanical properties of such a coating are shown to be on a par with or superior to those of solid chrome plating. The proposed coating costs less than does chrome plating.     

Transport properties of silmethylene homo-polymers and random copolymers: experimental measurements and molecular simulation

A novel class of silicon-containing rubbers is proposed as membrane materials for separation of hydrocarbons of natural and associated petroleum gas. Homo-polymers of general formulas -Si(CH₃)₂CH₂- (PDMSM) and -Si(CH₃)₂CH₂CH₂CH₂- (PDMSTM) and the copolymers with the same randomly alternating repeat units were prepared by thermal initiated polymerization of strained silicon-containing four-member cycles. These polymers have low glass transition temperatures and reveal solubility controlled gas permeation properties. The highest permeability is characteristic for PDMSM, however, it has poor film forming properties. On the other hand, amorphous copolymers exhibit combination of good film forming properties and relatively high permeability. Transport properties of PDMSM were successfully simulated by molecular dynamics using a very efficient united-atom force field.     

Heat-Resistant Antifrictional Composites with a Highly Alloyed Nickel Matrix

Technology for the production of new materials based on the heat-resistant powder metallurgy nickel alloy ÉP975 was developed, and the mechanical and tribological properties of these investigated. The formation features of the metallographic structure of the materials was studied. Recommendations for the practical use of the new composites are given.     

Small but strong: A review of the mechanical properties of carbon nanotube-polymer composites

The superlative mechanical properties of carbon nanotubes make them the filler material of choice for composite reinforcement. In this paper we review the progress to date in the field of mechanical reinforcement of polymers using nanotubes. Initially, the basics of fibre reinforced composites are introduced and the prerequisites for successful reinforcement discussed. The effectiveness of different processing methods is compared and the state of the art demonstrated. In addition we discuss the levels of reinforcement that have actually been achieved. While the focus will be on enhancement of Young’s modulus we will also discuss enhancement of strength and toughness. Finally we compare and tabulate these results. This leads to a discussion of the most promising processing methods for mechanical reinforcement and the outlook for the future.     

Structure Formation of Multiphase Compacts in the System SiC′ ― Carbon. Part 3. Structure Formation in the System SiC′ ― Carbon during Sintering

The effect of particle size for the original silicon carbide and carbon powders and effects connected with influence of the original components structures, as well as the structure and phase composition of self-bonded silicon carbide are studied.     

Gas permeability of carborane-containing polyamides

The gas permeation properties of two novel polyamides comprising m-carborane groups in the backbone have been first studied. The polymers have been synthesized by the polycondensation of m-carboranedicarboxylic acids and two diamines. It has been found that the synthesized polyamides exhibit unexpectedly low glass transition temperatures (140 and 173°C). For a number of light gases, permeability (P) and diffusion (D) coefficients have been measured and solubility coefficients as the S = P/D ratio have been determined. The parameters found have been compared with the P, D, and S values of other aromatic polyamides. It has been shown that according to these transport parameters, the novel polyamides are similar to many of the previously studied aromatic polyamides.     

Carbon‐Nanotube–Polymer Nanocomposites for Field‐Emission Cathodes

The electron field‐emission (FE) characteristics of functionalized single‐walled carbon‐nanotube (CNT)–polymer composites produced by solution processing are reported. It is shown that excellent electron emission can be obtained by using as little as 0.7% volume fraction of nanotubes in the composite. Furthermore by tailoring the nanotube concentration and type of polymer, improvements in the charge transfer through the composite can be obtained. The synthesis of well‐dispersed randomly oriented nanotube–polymer composites by solution processing allows the development of CNT‐based large area cathodes produced using a scalable technology. The relative insensitivity of the cathode's FE characteristics to the electrical conductivity of the composite is also discussed.     

Structure and properties of strengthening layer on Hardox 450 steel

The microstructure and microhardness distribution in the surface of low-carbon Hardox 450 steel coated with alloyed powder wires of different chemical compositions are studied. It is shown that the microhardness of 6–8?mm-thick surfaced layer exceeds that of base metal by more than two times. The increased mechanical properties of surfaced layer are caused by the submicro and nanoscale dispersed martensite, containing the niobium carbides Nb₂C, NbC and iron borides Fe₂B. In the bulk plates, a dislocation substructure of the net-like type with scalar dislocation density of 10¹¹?cm^?2 is observed. The layer surfaced with the wire containing B possesses highest hardness. The possible mechanisms and temperature regimes of niobium and boron carbides in surfacing are discussed.     

Binding of aroma compounds with legumin. III. Thermodynamics of competitive binding of aroma compounds with 11S globulin depending on the structure of aroma compounds

This paper considers the prominent features in competitive binding of aroma esters from their mixtures to 11S globulin of broad beans (legumin) in aqueous medium at pH 7.2 and ionic strength of 0.05 mol dm⁻³. Series of alkyl acetates (C₄–C₈) and methyl esters of carbonic acids (C₅–C₉), differing in the length of hydrocarbon chain, have been under our studying. To accomplish the ends of the study, a combination of ultrafiltration and gas–liquid chromatography (GC) has been used. An increase in the length of hydrocarbon chain of the aroma esters brought about greater binding affinity for the protein, the occurrence of some structural restrictions in the interior of the protein molecule, preventing binding, and the change in the binding mechanism of the aroma compounds at the specific critical length of hydrocarbon chain. Differential scanning microcalorimetry data suggested that the revealed changes in the binding mechanism of the studied aroma compounds were attributable to the conformational modification of the protein globule as a result of binding with the aroma compounds. A distinguishing feature in binding of methyl esters of carbonic acids with legumin was their greater binding affinity for the protein as compared with alkyl acetates. The mutual effect of aroma compounds on binding from their equimolar mixtures to the protein made itself evident, firstly, as a drastic increase in the binding extent of aroma esters, having rather long hydrocarbon chain and, secondly, as a dramatic change in the binding mechanism of the aroma esters with relatively short hydrocarbon chain.