Abstract: The axial compression mechanical behavior of Reactive Power Concrete (RPC) circular columns which confined by the spiral hoop of yield strength 600MPa are tested, and the tie spacing and volume tie ratio were used to evaluate the RPC columns failure modes, load-displacement relationship and yield characteristics of high-strength stirrups. The results show that the peak stress of the 250mm diameter circular column with no reinforcement can be up to 144.4MPa but with brittle failure mode, and the large volume tie ratio can increase the peak stress to 180MPa and failure by ductility; also, the high-strength spiral stirrups do not yield at the peak axial load, and the effective confined stress should be calculated according to the measured stirrups strain , and the remaining strength can be ensured the good ductility of the RPC specimens before reaching the ultimate failure mode; the peak strength and strain of RPC are proportional to linearly increase with effective confinement stress, but the proportion coefficient is smaller than that of ordinary concrete. The decline section of RPC stress-strain curve becomes smooth with the increase of effective binding stress, and the ductility coefficient of displacement gradually satisfies the ductility design requirements. The measured RPC stress-strain curve agrees well with the confined concrete Mander model and can be used conservatively. According to the test results, the calculation formula and the construction measurements of the axial compression capacity of the RPC with the spiral stirrup confined are put forward, which is convenient for the popularization and application of the confined RPC columns in the practical engineering.

Abstract: Created are the sorbents based on silica gel non-covalently modified with partially hydrogenated heterocyclic compounds (PHHC), containing nitrogen as donor atoms for purification of aqueous media from technogenic contaminants. The investigations show that the modified silica gel is characterized by a sorption capacity relatively higher than that of unmodified one. The sorption degree of metal ions is studied depending on their concentrations, total mineralization and pH value of the solutions. Conditions for selective sorption of microquantities of Eu3+ which has been used as chemically identical to 241Am are described. Moreover it was shown that PHHCmodified silica gel was potential to use as the sorbent to concentrate the Eu3+ and Sr2+ metal ions with initial concentrations near 1 mg∙L–1 for the quantitative analysis. Also the possible mechanism of metal ion sorption on the developed sorbents was proposed.

Abstract: The effect of water on compacted clay material with the use of triaxial compression was studied, and models for predicting shear strength parameters were also developed. The results show that cohesion decreases exponentially with increasing water content and exponentially increases with increasing degree of compaction. The angle of internal friction decreases in a convex quadratic parabolic law with increasing water content and increases with a concave quadratic parabolic law with an increase in the degree of compaction; Cohesion and internal friction angle are two-dimensional quadratic functions of water content and degree of compaction and have relatively large values of the shear strength parameter.

Abstract: The research found that the surface texture applied to the cutting tool could improve the frictional states of tool-chip and tool-workpiece effectively. In order to study the technology of surface texture how to effect the cutting performance of the integral end milling cutter for cutting titanium alloy (Ti6AlV).The longitudinal grooves, lateral grooves and pits were prepared by laser processing technique on the rake face of milling tool made of YG6X, which was to explore the cutting performance of non-texture tools and texture tools under the condition of dry and lubrication. As the results, compared with the non-textured tools, the longitudinal micro-groove and micro-pit could effectively reduce the milling force, increase the chip curl and improve the anti-sticking properties of the tool, thereby the oxidation wear, adhesive wear of the rake face and the abrasion wear of the flank face were alleviated as well. The experimental results demonstrated that the milling force of the tool with longitudinal micro-groove was reduced by 62% and the width of wear on rake face was reduced by 68%, the wear width on the flank face of the micro-pits tool was decreased by 42.6%.The direction of micro-groove on the tool’s rake face had a great influence on the anti-sticking properties, and the tools with longitudinal micro-grooves had the best anti-sticking property. The fine medium played a major role in improving the friction between the tool-chip friction pairs.