Study on the EMD Processing Method of Cylinder with Multiple Diagonal Slits
Aiming at complex shape of cylinder with multiple diagonal slits and difficult to processing using traditional processing method. the paper adopt two methods of EMD shaping and trajectory to processing slits of cylinder with multiple diagonal slits. Compared the processing quality of two processing method by the following aspects, such as the electrode material and fabrication technology, the level of difficulty with control of slits processing and Factors determine the accuracy of slits and so on. As can be seen from the comparison, for EDM forming method, processing electrode complex and inconvenient, but the process is simple relatively, have no use for complicated electrical control. For EDM trajectory method, processing electrode is simple and convenient, but the process is complicated relatively. It can process slits closer to the ideal shape through the establishment of a precise trajectory equation and using complicated electrical control.
Ultrasonic Rotary Motor Using a Longitudinal-Torsional Vibration Converter
Characteristics of ultrasonic rotary motors using a converter from longitudinal vibration to torsional one are studied. The longitudinal-tortional vibration converter consists of (1) cylindrically arranged thin rods bent at a longitudinal node part, (2) a cylinder with a diagonally slitted vibration converting part, (3) a slitted converting disk and cylindrical parts joined with a bolt. Ultrasonic motors consist of such a converter mentioned above with a driving part at its free edge and a rotor part clamped statically to a driving surface with corned disk springs. Maximum torque over 80 kgf·cm is obtained using the converter of 40 mm diameter.
Experimental investigation of the geotechnical properties and microstructure of lime-stabilized saline soils under freeze-thaw cycling
Abstract The Song-Nen Plain in northeastern China holds one of the three largest expanses of soda saline-alkali soil in the world. Due to its disadvantageous geotechnical properties, the saline soil in this area is unable to meet the needs of construction projects. This study evaluates the stabilizing effect of adding lime to such soils. Specifically, it investigates how the physicochemical and mechanical properties and microstructure of soda saline-alkali soil are altered by lime and how these changes are affected by both freeze-thaw cycling and the duration of curing. The results reveal that adding lime to saline soil transforms clay particles into sand and silt particles and causes the pore size distribution (PSD) to become bimodal, with small-pore and macropore populations. An increase in lime content leads to an increase in the unconfined compressive strength (UCS) but a gradual decrease in both the cation exchange capacity (CEC) and plastic index. Freeze-thaw cycles break up coarse particles and aggregate finer particles, increasing the diameter of macropores and decreasing the USC; however, the effect on specimens with >9% lime is negligible. It is further shown that the geotechnical properties of the soil change immediately after the addition of lime, indicating that the cation exchange reaction takes place very quickly. Furthermore, the pozzolanic reaction leads to an increase in the percentage of sand-sized particles and a decrease in porosity after 28 days of curing. Overall, these results indicate that it is feasible to use lime to improve the engineering properties of soda saline-alkali soil in this area.