Concrete structures like roads and bridges require nondestructive testing methods to identify interior defects without destroying their structure. Most methods send sound waves into the material and ...

Figure 1. Ultrasonic testing using pulse echo and through-transmission methods. Pulse echo (left and center) uses a transducer that sends and receives ultrasound energy, producing both A- and B-scan ...

Scientists in Finland transmitted electricity through air using sound waves, lasers, and radio frequencies, creating ...