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.
One-dimensional longitudinal-torsional vibration converter with multiple diagonally slitted parts
For increasing the available vibration velocity of the one-dimensional longitudinal-torsional vibration converter, a new type of complex vibration converter with multiple slitted parts installed in the positions avoiding longitudinal nodal positions along the converter for decreasing the maximum vibration stress level at the vibration nodal part was studied. The free end of the converter vibrates in an elliptical or circular locus. Complex vibration systems with elliptical to circular or rectangular to square loci can be applied effectively for various high-power applications, including ultrasonic welding of metal or plastics, ultrasonic wire bonding of IC, LSI and electronic devices, and also ultrasonic motors. The converter with multiple slitted parts was improved in the vibration stress level and the quality factor compared with the converter with single slitted part.
Development of an Analytical Method for Explosive Residues in Soil
Abstract : An analytical method was developed to determine the concentrations of HMX, RDX, TNB, DNB, Tetryl, TNT and 2,4-DNT in soil. The method involves extracting a 2-g sample with 50 mL of acetonitrile using an ultrasonic bath procedure for 18 hr. A 10-mL portion of the extract is diluted with 10 mL of water, filtered through a 0.45-micrometer Millex SR filter, and analyzed by RP-HPLC using a fixed 254-nm UV detector. Separations were obtained on an LC-18 column eluted with 50:50 water-methanol. Retention times were 2.55, 3.82, 5.16, 6.25, 7.04, 8.47 and 10.15 min for HMX, RDX, TNB, DNB, Tetryl, TNT and 2,4-DNT, respectively. Confirmation of analyte identities is recommended by RP-HPLC on an LC-CN column using 50:50 water-methanol. Kinetic studies using naturally contaminated soil indicated that equilibrium was achieved within 24 hr for the majority of soils and analytes studied. The method provides linear calibration curves over a wide range of concentrations. Reporting limits were conservatively estimated at 1.6, 1.8, 1.5, 0.5, 5.5, 0.8 and 0.8 micro grams/g for HMX, RDX, TNB, DNB, Tetryl, TNT and 2,4-DNT. Analytical precision was estimated at + or - 0.44, 0.51, 0.43, 0.13, 1.24, 0.27 and 0.20 micro grams/g, respectively, in the range of homogeneous variance near the detection limits. At higher concentrations the relative standard deviation was constant at 2% for HMX, RDX, DNB and TNB, 3% for TNT and 2,4-DNT, and 6% for Tetryl.