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In wire electro-discharge machining with an extremely high travelling speed of wire electrode (WEDM-HS), the emulsion is used as working liquid. Because there exists a functional electrolyte, the EDM spark can operate under a relatively large spark gap size condition, and this would facilitate the removal of machined debris. An investigation has been made into the machining feasibility when WEDM-HS has been employed to process Al2O3particle reinforced aluminum alloy 6061 with 10-vol% Al2O3(10ALO). And the material removal rate (MRR) has been examined in this study. Since there are many factors that can influence the MRR in the WEDM-HS process, in order to determine which is the most important factor and to optimize the machining parameters, the relative importance of the various machining parameters on material removal rate was established by utilizing an orthogonal experimental analysis. The results of the analysis suggest that to achieve a high MRR for particulate reinforced aluminum 6061 with 10-vol% Al2O3, the duty cycle is the most influential factor among current, pulse duration and duty cycle. And the impact of the different factors follows the sequence of duty cycle > current > pulse duration.

The buckling deformation and stress distribution of the tubing nearby the packer would be seriously influenced by the packer constraints. This paper focused on the Strength analysis of transitional segment. The method to calculate the buckling deformation and the equivalent stress of transitional segment were derived considering the tubing boundary and continuity condition, adopting the fourth-order nonlinear ordinary differential equations and helical buckling strength method. This study makes up for the weakness of traditional stress analysis of the buckling tubing nearby the packer in vertical well, improves the pertinence and accuracy of stress analysis of buckling tubing. The results of analysis show that with the axial pressure increasing lead to the length of the transitional segment irregular fluctuations and the maximum equivalent stress increasing. The equivalent stress would gradually reduce and finally approach a constant.

The coal bed methane is an important part of the Chinese energy. To finding some effect ways to collect gas during the coal mining process will increasing the using rate of coal mine and reducing greenhouse gas emission. The most effective way is coal and gas co-mining, and the main technology of the coal and gas co-mining are gas pre-extraction before mining, gas extraction of pressure relief, gas extraction of adjacent layer, gas extraction of goaf and top fractured zone, Gas extraction of excavation roadway and so on. Based on the technique system of coal and gas co-mining and the key problems existing in coal and gas extraction technology, to improve energy efficiency and reduce coal mine disaster.

A new concavo-convex electrode has been designed and employed and it was reported that electrical discharge machining (EDM) of particulate reinforced metal matrix composites with this kind of new electrode can accelerate the debris discharge during machining so that it has a higher material removal rate (MRR) compared to the case where a normal electrode was employed. Since there are many factors that can affect the MRR in the EDM process with the concavo-convex electrode, in order to determine which is the most important factor and to optimize the machining parameters, the relative importance of the various cutting parameters on material removal rate was established using an orthogonal experimental analysis in this study. The results of the analysis suggest that to achieve a high MRR for particulate reinforced aluminum 6061 with 10-vol% Al2O3 (10ALO) or 20vol% Al2O3 (20ALO) using a concavo-convex electrode, the duty cycle is the most influential factor among current, pulse duration and duty cycle.

The RE/Mn co-doped Co-Zn ferrites were prepared by the ceramic method. Infrared absorption and emission properties were obtained by investigating those ferrites. The IR spectra in the range from 400 to 1200 cm-1 were observed. Mainly, three bands were investigated. The high-frequency bands and low-frequency bands were assigned to the tetrahedral and octahedral complexes, respectively. The intensity of all the bands is found to increase while a decrease in broadness, which is explained on the cation distribution in the tetrahedral and octahedral sites were modified by RE/Mn addition. The Mn substitutes the Fe3+ and enters into the octahedral sites; while the partial RE3+ ions are apt to diffuse to the grain boundaries and others enter into the spinel lattice .This can be explained on the basis of ionic radii and ratios of the substituted cation. The results indicate that IR emissivity seems to be increasing with RE/Mn ratio within 8-14 μm wavebands. The maximum infrared emissivity is 0.968 when La/Mn ratio of 0.20 within 8-14 μm wavebands.

The interface bond between steel fibers and concrete matrix is the key of carrying capacity of steel fiber reinforced concrete(SFRC). In marine tidal fluctuation zone and splashed area, steel fibers will be rusty, and the bending toughness of SFRC was weakened. In this study, we tried to improve corrosion resistance of steel fiber and the interface bond strength by depositing zinc phosphate coating on steel fiber. These zinc phosphate steel fiber reinforced concrete(ZSFRC) have higher anti-corrosion ability. After corrosion they still have higher bending toughness than common SFRC.

This study investigates four extraction methods (water extraction, toxicity characteristics leaching procedure (TCLP), modified TCLP with pH control and sequential chemical extraction (SCE)), each representing different liquid-to-solid (L/S) ratios, pH controls, and types of leachant and their effects on the leaching concentration of Pb in cathode ray tubes (CRTs).The results indicated that for extraction with distilled water,the lead leaching concentration (mg/L) decreased with L/S ratio in the range of 2-100. The results also showed that the leaching concentration was strongly pH-dependent in the TCLP and modified TCLP tests. In modified TCLP tests,in the case of pHs lower than 6.3,the leaching concentrations of Pb decreased with an increase in pH. Due to the nature of amphoteric elements, in the case of pHs higher than 7, the Pb leaching concentration increased with increasing pH. In SCE tests, the Pb speciation approached the extractable carbonate bound fraction. Both amounts of Pb leached from the SCE and modified TCLP tests were much higher than those for the regular TCLP and water extraction tests. The initial particle size of samples have great effect on the leachability of Pb from waste CRTs.

Silicon carbide (SiC) powders have been prepared at 1200–1500°C by carbothermal reduction of two kind precursors of carbonl/silica mixtures: coked rice husk with high-carbon content, and gasified rice husk with low-carbon content mixed with carbon powders as an external carbon sources. The differences in nature of carbon matter in the external source and coked rice husk, and their effect on SiC synthesis have been studied by TG-DSC, TEM, XRD and laser diffraction technique. Experimental results show that the difference in nature of carbon source may affect the formation of SiC powders. The characteristics of the synthesized SiC particles strongly depend on the characteristics of the carbon sources.

This paper presents a electrochemical-mechanical combined polishing progress of Cr12 hardening steel with a new kind of embedded tool. The embedded tool has been composed of two parts, the metal base acting as electrode and the inlayer with electroplating diamond grains on its outside surface which serves as mechanical grinding abrasive. The two parts are agglutinated by adhesive which can keep a good insulation of the inlayer during the mechanical process. The inter-electrode gap can be changed by altering the metal base and inlayer’s diameter. Through the investigation of numerical simulation and polishing experiment, it can be found that lower feed, reciprocate speed, longer trip of reciprocating, smaller diamond grains make better surface quality.