Papers by Author: Ming Kuen Chang

Abstract: This research expects to investigate yet at domestic-dump truck driver, carry on the preliminary vibration determination. This research studies ten dump trucks in Yunlin County and precede questionnaire at the sandstone field. The ISO 2631-1:1997 and Article 301 in Taiwan’s regulation “Rules of Equipment and Measures for Protecting Labors’ Safety and Health” are used to evaluate tolerable exposure time per day for drivers. And in accordance with ISO 2631-5:2004 to assessment healthy risk for dump truck driver. In accordance with Article 301 of Labor Safety and Health regulation in Taiwan’s to estimate tolerable exposure time. A half tolerable exposure time present lower than 8 hours. In accordance with ISO 2631-1:1997 to estimate tolerable exposure time, no matter use equation B.1 or B.2 to calculate tri-axis compose acceleration. All tolerable exposure time present lower than 8 hours. If basis of ISO 2631-5:2004 to evaluation healthy risk for driver.

Abstract: Intrinsically conductive polymer-Polyaniline had high conductivity and many other properties, such as environmental stability and rather simple synthesis. In addition, doping with organic acids could enhance its processing, so it had wide range of applications, such as solar cells, antistatic and electromagnetic interference shielding. In this study, the organic amine 1-Dodecylamine (DOA) modification of sodium montmorillonite (NA+-MMT), and conducting polymer / layered silicate salt nanocomposites (PANI-PTSA/DOA-MMT) had been prepared by doping aniline with organic acid (PTSA), then added organic clay. The thermal, electrical properties and EMI effects of nanocomposites had discussed by XRD, TEM, EMI, TGA analysis, conduction measure and EMI tested. The results indicated the organo-clay interlayer distance expanded from 1.29 to 1.8 nm, and DOA-MMT dispersed in the material, that formed an exfoliated nanocomposite. The thermal stability of nanocomposites depended on content of DOA-MMT, material had the better thermal stability when DOA-MMT load was 5 wt. %. The nanocomposites had the best conductivity when DOA-MMT load was 1 wt. % as well as the electromagnetic shielding effectiveness was increase with increase in conductivity. In addition, the electromagnetic shielding of nanocomposites also depended on thickness and frequency of electromagnetic wave, the electromagnetic shielding was increased with increase in thickness and frequency.

Abstract: This study have used three different montmorillonite by anionic, nonionic and ammonium chloride modifier to prepare polyethylene / montmorillonite (MMT) nanocomposites. The kneading process doped modified MMT to polyethylene, according with ASTM D638 to proceed hot-press works, and ASTM D256 to determine the izod pendulum impact resistance of plastics specimen. Prepared nanocomposites continue proceed in tensile and impact testing, finally, we observed low-density polyethylene layered silicate nanocomposites properties were improved, also found that anion modified montmorillonite had significant reinforcement effect in tensile and impact testing.

Abstract: During materials manufacturing process will cause defects occasionally, if the defects located at near surface of material where the testing is not easy to implement. When the defects was stress by outside loading, it will grow up even become fracture, if the material apply ultrasonic testing then can increase material security to ensure structural safety. Practice material defect shape is variable and need complex product procedure. In this study, using wire cutting method to make practice defects specimen instead of the real flaws material, the specimen was made of medium carbon steel and aluminum alloy, defects away from the surface is 2-4 mm, defect shape including round shape hole and square shape hole, bore diameter was 1-3 mm. Using ultrasonic straight beam probe and delay line probe, straight beam probe have 5 MHz and 10 MHz frequency, and delay line probe have 5 MHz, 10 MHz frequency too, finally, compared the relationship between the accuracy and depth of flaws, pore size, flaw shape, material of specimen. Research results demonstrate that accuracy didn’t relate to the flaw shape, flaw size, depth of flaws and material of specimen. The accurately of 10 MHz delayed probe shown the depth of flaw smaller, the measurement than other probes.