Microstructure evolution of AZ91D induced by high energy shot peening

A nanostructured surface layer was fabricated on a AZ91D magnesium alloy by using a high-energy shot peening(HESP).HESP induced structure along the depth of the treated sample surface layer was characterized by means of X-ray diffractometer (XRD),transmission electron microscope(TEM) and high resolution transmission electron microscope(HRTEM).The experimental results show that a deformed layer of about 50 μm has formed after HESP treatment and the average grain size increases from about 40 nm in the surface layer to about 200 nm at the depth of 40 μm.The surface nanocrystallization can realize intercoordination of the dislocations slipping and dynamic recrystallization.The nanocrystalline grains have stacking faults and dislocation in their interiors.The microhardness of the top surface is about triplicate that of the coarse-grained matrix.

Investigation on Water Jet Treated Polyester/cotton Blended Cambric

Analytical examination was made to ascertain the effect of the high pressure water flow on the fabric properties.Polyester/cotton blended cambric was spurted by high pressure water flow. Fabric properties such as handle,thickness, tensile strength , stiffness and air permeability after the water treatment were investigated.

Numerical Simulation of High-Power Synthetic Jet Actuator Flowfield and its Influence on Mixing Control

Detailed two-dimensional unsteady numerical simulation is carried out to investigate a high-power synthetic jet actuator flow field and its design characteristic. Simultaneously, mixing control mechanism of coaxial jets with actuators is also studied. Firstly, excitation frequency （rotating speed）, piston displacement and its exit slot width have effect on the controlling ability and controlling efficiency of actuator. With the invariable model and con- cerned parameters, the actuator becomes more desirable as the rotating speed increases. Average velocity and maximal velocity at the actuator exit section increase as the piston displacement enlarges or the exit slot width decreases. But the actuator does not always exhibit good performance with the narrower exit. Secondly, the synthetic jets also have the ＂push＂ effect on the coaxial jets, which results in the fluctuation of vorticity and temperature distribution of mixing flowfield. Finally, the employment of synthetic jet actuator can achieve mixing enhancement significantly.

Flow effects on jet energy loss with detailed balance

In the presence of collective flow a new model potential describing the interaction of the hard jet with scattering centers is derived based on the static color-screened Yukawa potential.The flow effect on jet quenching with detailed balance is investigated in pQCD.It turns out,considering the collective flow with velocity vzalong the jet direction,the collective flow decreases the LPM destructive interference comparing to that in the static medium.The gluon absorption plays a more important role in the moving medium.The collective flow increases the energy gain from gluon absorption,however,decreases the energy loss from gluon radiation,which is(1-vz)times as that in the static medium to the first order of opacity.In the presence of collective flow,the second order in opacity correction is relatively small compared to the first order.So that the total effective energy loss is decreased.The flow dependence of the energy loss will affect the suppression of high pThadron spectrum and anisotropy parameter v2in high-energy heavy-ion collisions.