The sound features of the weld pool status in plasma arc welding were systematically investigated after the sound signal was collected with a microphone. The results show that it is difficult to extract information ab...The sound features of the weld pool status in plasma arc welding were systematically investigated after the sound signal was collected with a microphone. The results show that it is difficult to extract information about the weld pool status directly in time domain although the sound signal varies with the weld pool behaviors to some extent. The frequency spectra of the sound signal contain plenty of information about the weld pool behaviors. It is shown from the analysis of the sound generation mechanism that the sound signal of plasma arc welding is mainly caused by the weld pool oscillation, the power source fluctuation and so on. R S algorithm is designed to determine the weld pool status, and it is able to offer the feedback information for the closed loop control of the penetration quality of plasma arc welding. [展开更多
Abstract Objectives To explore the potential use of ultrasound measurement (SoundScan 2000 Compact, Myriad Ultrasound Systems Ltd., Rehovot, Israel), and to assess both quantitative and qualitative properties of bone....Abstract Objectives To explore the potential use of ultrasound measurement (SoundScan 2000 Compact, Myriad Ultrasound Systems Ltd., Rehovot, Israel), and to assess both quantitative and qualitative properties of bone. Methods The speed of sound waves (SOS; m/s) propagating along the cortical bone was determined at the tibial shaft. The performance, reliability, validity, and clinical application of this system were evaluated in Japanese subjects. Results In phantom experiments, validity of this system was 0.04(%), coefficient variation (CV: %) in same-day tests was 0.12, in five-separate-day tests was 0.13, and in independent operators was 0.11, respectively. In experiments with Japanese subjects, CV in same-day tests was 0.38, in five-separate-day tests was 0.99, and in independent operators was 0.90, respectively. In addition, cortical bone status of 1176 Japanese subjects (372 males, 804 females) was clinically evaluated by SoundScan 2000 Compact. SOS was negatively correlated with body fat percentage (%), body fat (kg) and waist hip ratio in females and subjects with higher weight bearing index (leg strength/body weight; WBI) have higher SOS in females under the age of forty. Conclusions These findings indicate that the SoundScan 2000 Compact is a highly reliable and valid method for determining cortical bone status and body composition and WBI are closely related to cortical bone status in Japanese females.展开更多
文摘The sound features of the weld pool status in plasma arc welding were systematically investigated after the sound signal was collected with a microphone. The results show that it is difficult to extract information about the weld pool status directly in time domain although the sound signal varies with the weld pool behaviors to some extent. The frequency spectra of the sound signal contain plenty of information about the weld pool behaviors. It is shown from the analysis of the sound generation mechanism that the sound signal of plasma arc welding is mainly caused by the weld pool oscillation, the power source fluctuation and so on. R S algorithm is designed to determine the weld pool status, and it is able to offer the feedback information for the closed loop control of the penetration quality of plasma arc welding. [
文摘Abstract Objectives To explore the potential use of ultrasound measurement (SoundScan 2000 Compact, Myriad Ultrasound Systems Ltd., Rehovot, Israel), and to assess both quantitative and qualitative properties of bone. Methods The speed of sound waves (SOS; m/s) propagating along the cortical bone was determined at the tibial shaft. The performance, reliability, validity, and clinical application of this system were evaluated in Japanese subjects. Results In phantom experiments, validity of this system was 0.04(%), coefficient variation (CV: %) in same-day tests was 0.12, in five-separate-day tests was 0.13, and in independent operators was 0.11, respectively. In experiments with Japanese subjects, CV in same-day tests was 0.38, in five-separate-day tests was 0.99, and in independent operators was 0.90, respectively. In addition, cortical bone status of 1176 Japanese subjects (372 males, 804 females) was clinically evaluated by SoundScan 2000 Compact. SOS was negatively correlated with body fat percentage (%), body fat (kg) and waist hip ratio in females and subjects with higher weight bearing index (leg strength/body weight; WBI) have higher SOS in females under the age of forty. Conclusions These findings indicate that the SoundScan 2000 Compact is a highly reliable and valid method for determining cortical bone status and body composition and WBI are closely related to cortical bone status in Japanese females.
