Experimental Investigation on the Energy Storage Characteristics of Red Sandstone in Triaxial Compression Tests with Constant Confining Pressure

The elastic energy stored in deep rock in three-dimensional stress environment is the energy source of rockburst. To investigate the energy storage characteristics of deep rock under different confining pressures, a series of triaxial single-cyclic loading-unloading compression tests were conducted on red sandstone specimens under eight confining pressures. The input energy density, elastic energy density, and dissipative energy density of the specimen in axial, circumferential, and total directions can be obtained by the area diagram integration method. The results show that the input energy density in the axial direction accounts for the largest logarithmic proportion of the total input energy density, and the relationship between all energy density parameters and unloading level can be described by quadratic function. In the axial direction, there is a linear function relationship among elastic energy density, dissipative energy density, and input energy density. In the circumferential direction, there is a quadratic function relationship among elastic energy density, dissipative energy density, and input energy density. For the total energy density parameters of the rock specimen, the relationship among elastic energy density, dissipative energy density, and input energy density conforms to the quadratic function. According to the above correlation function, the elastic energy stored in deep rock under different confining pressures can be accurately obtained, which provides a foundation for studying the mechanism of rockburst under three-dimensional unloading from the energy perspective.

Selective Laser Melting Bone-Compatible Pure Titanium Porous Structure

In this paper the effect of selective laser melting (SLM) input energy density on densification behavior and tensile strengths of commercially pure (CP) titanium was investigated. Fully dense and high strength SLM CP titanium has been obtained. A complex bone-compatible tetrakaidecahedron based porous structure has been successfully SLM-fabricated with optimized laser parameters.

Nano-Materials Coupled with Non-Thermal Plasma Application in Environmental Protection

Nano-catalyst was prepared in the lab. Non-thermal plasma was generated by dielectric barrier discharge (DBD). Through nano-catalyst coupled with non-thermal plasma, a series of experiments for toluene decomposition were carried out. Based on reactor input energy density and removal efficiency and energy efficiency and inhibition for O3 formation, the load amount MnOx catalyst on the surface of γ-Al2O3 pellets were compared in the experiment. The results show the catalysis performance of 10 wt% MnOx/γ-Al2O3 coupled with non-thermal plasma resulted in higher removal efficiency of toluene and better energy efficiency. At the same time, 10 wt% MnOx/γ-Al2O3 operated on a better inhibition for O3 formation in the gas exhaust.

Superplastic Bulging Capability of Ti-6Al-4V Butt-Welded Plate by High Energy Beam Welding

The superplastic bulging capabilities of Ti-6Al-4V butt-welded plates with 0.8mm in thickness with high energy beam welding methods namely plasma arc welding (PAW), electron beam welding (EBW) and laser beam welding (LBW) are studied in virtue of superplastic bulging tests. Superplastic bulging tests are performed at the superplastic forming temperature 925°C under 1MPa gas pressure. The superplastic bulging capability is represented by the maximum relative bulging height h after fracture. Experimental results suggest that all of butt-welded plates with high energy beam welding methods possess good superplastic bulging capability. Among them, the maximum relative bulge height of LBW is the highest, that of EBW is slightly lower and that of PAW is the lowest. The higher the input energy density is, the bigger the bulge height will be. Furthermore their microstructure evolutions of various weld metals during superplastic bulging were systematically analyzed via metallographical tests. The relation between the microstructure of weld metal and its superplasticity is found. Metallographical analysis shows that the microstructure of Ti-6Al-4V weld metal with high energy beam welding methods is composed of fine acicular martensite. The higher the input energy density is, the finer the martensite structure will be. Upon heating, this martensite changes to a basketweave-like structure and upon bulging, the martensite structure have the trend of transforming to fine equiaxed grain. This can explained the reason why the Ti-6Al-4V butt-welded plates with high energy beam welding methods have excellent superplastic bulging capability.

Dependence of NOx Removal by Pulsed Streamer Discharge on the Input Energy Density to Nitric Oxide Ratio

Non-thermal plasma produced by pulsed power discharges in atmospheric pressure gases have been studied for the treatment of exhaust gases. In this paper, results are reported of short duration of tens of nanoseconds pulsed power applied to a mixture of nitric oxide (NO), nitrogen, oxygen, and water vapor, simulating flue gases to remove nitrogen oxide (NOx). The effects of the initial NO concentration and the pulsed repetition rate on the percentage of NO removal are reported. The results showed that all NO could be removed completely at different pulse repetition rates. NO removal ratio reached 100% at (3.2 ± 0.1) × 10