hoto-sensitive Hybrids Constructed from Diphenyliodonium and Metal-thiocyanates: Photo-induced Structure and Property Transformation

Strong electron-poor cation diphenyliodonium was firstly incorporated with transition metal thiocyanates to obtain three new photo-sensitive hybrids, (DPI)3[Mn(SCN)5(H2O)]∙0.25H2O (α-1), {(DPI)2[Ni(SCN)4]}n (α-2) and {(DPI)6[Cd3(SCN)12]}n (α-3) (DPI+ =diphenyliodonium), whose photo-induced structural transformations...

Modification of turbulence caused by cationic surfactant wormlike micellar structures in two-dimensional turbulent flow

An experimental study is performed to investigate the effects of the extensional rheological properties of drag-reducing wormlike micellar solutions on the vortex deformation and turbulence statistics in two-dimensional (2-D) turbulent flow. A self-standing 2-D turbulent flow was used as the experimental set-up, and the flow was observed through interference pattern monitoring and particle image velocimetry. Vortex shedding and turbulence statistics in the flow were affected by the formation of wormlike micelles and were enhanced by increasing the molar ratio of the counter-ion supplier to the surfactant, ξ, or by applying extensional stresses to the solution. In the 2-D turbulent flow, extensional and shear rates were applied to the fluids around a comb of equally spaced cylinders. This induced the formation of a structure made of wormlike micelles just behind the cylinder. The flow-induced structure influenced the velocity fields around the comb and the turbulence statistics. A characteristic increase in turbulent energy was observed, which decreased slowly downstream. The results implied that the characteristic modification of the 2-D turbulent flow of the drag-reducing surfactant solution was affected by the formation and slow relaxation of the flow-induced structure. The relaxation process of the flow-induced structure made of wormlike micelles was very different from that of the polymers.

Numerical investigation on the compressor for gas-entraining diffuser EGR

Exhaust Gas Recirculation (EGR) is an effective way to reduce nitrogen oxide (NO x) emissions, and the EGR application increases the engine backpressure to some extent. In this paper, a new EGR method named gas-entraining diffuser EGR was proposed to reduce pumping loss. It introduces the exhaust gas into the compressor diffuser inlet where the static pressure is the lowest without blades fouled by exhaust gas. As a result, lower pressure at the turbine upstream can achieve EGR. Then, a newly designed induced structure not only introduces exhaust gas into the compressor diffuser but also reduces the energy loss caused by EGR application. Furthermore, the performance of compressor with different induced angles of the induced structure was investigated using simulation method. Results showed that the compressor’s adiabatic efficiency was the best when the induced angle was 20°. Regarding the induced angle of 20°, the adiabatic efficiency drop of compressor was in the range of 0.8%–12%. Approximately 10% of the adiabatic efficiency drop was caused by the induced structure, the other was mainly from the flow loss and mixing loss in diffuser system. The induced structure mainly affected the static pressure difference between induced structure inlet and impeller outlet ([Formula: see text]). When the impeller mass flow was 0.23 kg/s, [Formula: see text] was 11.21, 13.95, 15.59, 17.18 kPa respectively with corresponding induced angles of 20°, 30°, 40°, 50°. The primary energy loss leading to the adiabatic efficiency drop of compressor with induced structure occurred in diffuser system. It was caused by the mixing process of induced gas and impeller exit gas, and the enhanced effect from the shroud side’s impeller jet-wake and volute tongue.

Shock-Wave Properties and Deformation-Induced Structure of Commercial-Purity Titanium

The shock compressive wave profiles of commercial-purity titanium samples under different loading conditions have been measured. The spall strength of titanium as a function of the strain rate and temperature of deformation has been found. High-rate plastic deformation mechanisms have been studied. High-rate plastic deformation under the investigated loading conditions has been shown to occur by slip and twinning. The α → ω transformation has been established to begin at 12.2 GPa.