By designing the hydrostatic control system for high-speed telescopic boom forklifts,a combined control mode is applied using the engine and variable pump.Accordingly,the forklift joint operation is realized by simultaneously controlling the operational and driving mechanisms.Meanwhile,the engine rotary speed is automatically and optimally adjusted based on variable loadings.Therein,the engine power can be fully exploited.
Ammonia (NH3) is the main alkaline gas in the atmosphere and neutralizes acidic gases to form haze. Silver-based catalysts are widely used in the field of ammonia selective catalytic oxidation (NH3-SCO) due to their low cost and high efficiency. However, Ag-based catalysts with high activity at low temperatures are usually loaded with large amounts of Ag. To further reduce the cost of Ag-based catalysts, we used a “reduction-aggregation” strategy to aggregate isolated Ag atoms that were highly dispersed into Ag nanoparticles (AgNPs) so that more active centers could be exposed under low Ag loading conditions. Significant AgNPs size effects in the NH3-SCO reaction were found, including the effect of AgNPs size on catalyst activity and stability. Finally, novel Ag/Al2O3 catalysts with high efficiency and stability were developed at a low Ag loading of 1 wt.% and achieved better NH3-SCO performance than 10% Ag/Al2O3, which significantly reduced the catalyst cost.
Based on Pro / ENGINEER Wildfire,the 3D-model of the engine cylinder was designed and the parts were assembled.Then Mechanism module was applied in the dynamic simulation,kinematics and dynamics analysis of the cylinder,which is expected to optimize the product design for high-effect,preciseness and low cost.
Phosphogypsum (PG) occupies a large amount of land due to its large annual production and low utilization rate, and at the same time causes serious environmental problems due to toxic impurities. PG is used for mine backfill, and industrial solid waste is a curing agent for PG, which can save the filling cost and reduce environmental pollution. In this paper, PG was used as a raw material, combined with steel slag (SS) and ground granulated blast-furnace slag (GGBS) under the action of an alkali-activated agent (NaOH) to prepare all-solid waste phosphogypsum-based backfill material (PBM). The effect of the GGBS to SS ratio on the compressive strength and toxic leaching of PBM was investigated. The chemical composition of the raw materials was obtained by XRF analysis, and the mineral composition and morphology of PBM and its stabilization/curing mechanism against heavy metals were analyzed using XRD and SEM-EDS. The results showed that the best performance of PBM was achieved when the contents of PG, GGBS, and SS were 80%, 13%, and 7%, the liquid-to-solid ratio was 0.4, and the mass concentration of NaOH was 4%, with a strength of 2.8 MPa at 28 days. The leaching concentration of fluorine at 7 days met the standard of groundwater class IV (2 mg/L), and the leaching concentration of phosphorus was detected to be less than 0.001 mg/L, and the leaching concentration of heavy metals met the environmental standard at 14 d. The hydration concentration in PBM met the environmental standard. The hydration products in PBM are mainly ettringite and C-(A)-S-H gel, which can effectively stabilize the heavy metals in PG through chemical precipitation, physical adsorption, and encapsulation.
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