Field Test Performance of Noncontact Ultrasonic Rail Inspection System

2017 ◽  
Vol 143 (5) ◽  
pp. 04017007 ◽  
Author(s):  
Stefano Mariani ◽  
Thompson Nguyen ◽  
Xuan Zhu ◽  
Francesco Lanza di Scalea
Keyword(s):  
Field Test ◽  
Test Performance ◽  
Inspection System ◽  
Rail Inspection

Predictions of defect detection performance of air-coupled ultrasonic rail inspection system

2017 ◽  
Vol 17 (3) ◽  
pp. 684-705 ◽  
Author(s):  
Stefano Mariani ◽  
Francesco Lanza di Scalea
Keyword(s):  
Field Test ◽  
Defect Detection ◽  
Guided Waves ◽  
Numerical Study ◽  
Detection Performance ◽  
Probability Of Detection ◽  
Inspection System ◽  
False Alarms ◽  
Operating Variables ◽  
Rail Inspection

A rail inspection system based on ultrasonic guided waves and non-contact (air-coupled) ultrasound transduction is under development at the University of California at San Diego. The system targets defects in the rail head that are major causes of train accidents. Because of the high acoustic impedance mismatch between air and steel, the non-contact system poses severe challenges and questions on the defect detection performance. This article presents an extensive numerical study, conducted with a local interaction simulation approach, to model the ultrasound propagation and interaction with defects in the proposed system. This model was used to predict the expected detection performance of the system in the presence of various defects of different sizes and positions, and at varying levels of signal-to-noise ratios. When possible, operating variables for the model were chosen consistently with the field test of an experimental prototype that was conducted in 2014. The defect detection performance was evaluated through the computation of receiver operating characteristic curves in terms of probability of detection versus probability of false alarms. The study indicates that despite the challenges of non-contact probing of the rail, quite satisfactory inspection performance can be expected for a variety of defect types, sizes, and positions. Beyond the specific cases examined in this article, this numerical framework can also be used in the future to examine a larger variety of field test conditions.

scholarly journals A 1-Year Study of Endurance Runners: Training, Laboratory Tests, and Field Tests

2014 ◽  
Vol 9 (6) ◽  
pp. 1019-1025 ◽  
Author(s):  
Andy Galbraith ◽  
James Hopker ◽  
Marco Cardinale ◽  
Brian Cunniffe ◽  
Louis Passfield
Keyword(s):  
Field Test ◽  
Test Performance ◽  
Repeated Measures ◽  
Lactate Threshold ◽  
Laboratory Tests ◽  
Field Tests ◽  
Running Economy ◽  
Training Time ◽  
Repeated Measures Anova ◽  
Endurance Runners

Purpose:To examine the training and concomitant changes in laboratory- and field-test performance of highly trained endurance runners.Methods:Fourteen highly trained male endurance runners (mean ± SD maximal oxygen uptake [VO2max] 69.8 ± 6.3 mL · kg−1 · min−1) completed this 1-y training study commencing in April. During the study the runners undertook 5 laboratory tests of VO2max, lactate threshold (LT), and running economy and 9 field tests to determine critical speed (CS) and the modeled maximum distance performed above CS (D′). The data for different periods of the year were compared using repeated-measures ANOVA. The influence of training on laboratory- and field-test changes was analyzed by multiple regression.Results:Total training distance varied during the year and was lower in May–July (333 ± 206 km, P = .01) and July–August (339 ± 206 km, P = .02) than in the subsequent January–February period (474 ± 188 km). VO2max increased from the April baseline (4.7 ± 0.4 L/min) in October and January periods (5.0 ± 0.4 L/min, P ≤ .01). Other laboratory measures did not change. Runners’ CS was lowest in August (4.90 ± 0.32 m/s) and highest in February (4.99 ± 0.30 m/s, P = .02). Total training distance and the percentage of training time spent above LT velocity explained 33% of the variation in CS.Conclusion:Highly trained endurance runners achieve small but significant changes in VO2max and CS in a year. Increases in training distance and time above LT velocity were related to increases in CS.

Physiological and Field Test Performance Changes of Community College Football Players Over a Season

1995 ◽  
Vol 9 (4) ◽  
pp. 211
Author(s):  
Kimberly A. dos Remedios ◽  
Robert L. dos Remedios ◽  
Steven F. Loy ◽  
George J. Holland ◽  
William J. Vincent ◽  
...  
Keyword(s):  
Community College ◽  
Field Test ◽  
Test Performance ◽  
College Football ◽  
Football Players
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