Sensing the gas metal arc welding process

Control of gas metal arc welding (GMAW) requires real-time sensing of the process. Three sensing techniques for GMAW are being developed at the Idaho National Engineering Laboratory (INEL). These are (1) noncontacting ultrasonic sensing using a laser/EMAT (electromagnetic acoustic transducer) to detect defects in the solidified weld on a pass-by-pass basis, (2) integrated optical sensing using a CCD camera and a laser stripe to obtain cooling rate and weld bead geometry information, and (3) monitoring fluctuations in digitized welding voltage data to detect the mode of metal droplet transfer and assure that the desired mass input is achieved

Roll Maneuver Control of UCAV Wing Using Anisotropic Piezoelectric Actuators

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76333/1/AIAA-2002-1720-656.pd

Validation of a single-stage submaximal treadmill walking test.

The single-stage treadmill walking test of Ebbeling et al. is commonly used to predict maximal oxygen consumption (.VO(2max)) from a submaximal effort between 50% and 70% of the participant\u27s age-predicted maximum heart rate. The purpose of this study was to determine if this submaximal test correctly predicts .VO(2max) at the low (50% of maximum heart rate) and high (70% of maximum heart rate) ends of the specified heart rate range for males and females aged 18 - 55 years. Each of the 34 participants completed one low-intensity and one high-intensity trial. The two trials resulted in significantly different estimates of .VO(2max) (low-intensity trial: mean 40.5 ml . kg(-1) . min(-1), s = 9.3; high-intensity trial: 47.5 ml . kg(-1) . min(-1), s = 8.8; P \u3c 0.01). A subset of 22 participants concluded their second trial with a .VO(2max) test (mean 47.9 ml . kg(-1) . min(-1), s = 8.9). The low-intensity trial underestimated (mean difference = -3.5 ml . kg(-1) . min(-1); 95% CI = -6.4 to -0.6 ml . kg(-1) . min(-1); P = 0.02) and the high-intensity trial overestimated (mean difference = 3.5 ml . kg(-1) . min(-1); 95% CI = 1.1 to 6.0 ml . kg(-1) . min(-1); P = 0.01) the measured .VO(2max). The predictive validity of Ebbeling and colleagues\u27 single-stage submaximal treadmill walking test is diminished when performed at the extremes of the specified heart rate range