# Review of Structural Health Monitoring Techniques in Pipeline and Wind Turbine Industries
## 5 UAV Systems for Health Monitoring  
The Functioning of UAV sensors and receivers and LIDAR data collected from RGIPT Amethi of pipe leakages are shown in Figure 17.  
Figure 16: Health monitoring systems of wind turbines [185; 189; 190; 192]. SESHMS: server health monitoring system; WSN: wireless sensor network; DSL: digital subscriber line; DAS: data acquisition system.  
Figure 17: Functioning of UAV sensors and receivers and LIDAR data collected from RGIPT Amethi of pipe leakages. The image is in the form of LIDAR data points.  
Leakages in pipelines lead to massive losses; even a leak as small as 1% in a 20-inch-thick pipeline can lead to a loss of more than 500,000 barrels of oil every year. For a solution to this, it is important that these leaks are detected at the right time. One of the few techniques is to use UAV for inspecting a pipeline; this is not only a detection method but is also a method to monitor the environmental conditions in the vicinity of the pipeline. The benefit with using UAVs is that they are capable of covering larger areas in a smaller amount of time as compared to manual inspection. This makes it a cost-effective and time-efficient detection method. The use of UAVs is not only limited to pipelines, and they are now being used in nuclear power plants, chemical plants, etc. Several toxic gases are processed each day in chemical plants across the world, and it is important that not even a pinch of such gases leak out into the atmosphere. Thus, UAVs come in handy, as they efficiently sense even the smallest amount of leakage through the sensors mounted on top of it, which sends signals to the controllers who react accordingly. A payload can be installed on various platforms, which is used to detect gas leakage, and the installation of payload can be seen as a possible solution to detect and then mitigate gas leakage. However, the solution provided by the payload installation is not just concealed to UAVs. In a research study, a UAV was operated at a height of about 40 m from the ground at a speed of 30 km/h for a time period of about 2 h, and the maximum weight of the payload was kept at 5 kg.  
At first glance, it was found that only methane gas in the temperature range of 15 to 20 degrees Celsius was leaked out in a pipeline of pressure 1500 psi. To track muffled frequencies and waves, leaks, and different frequencies in metallic machine frameworks, industrial air, vacuum systems, and pressurized gas pipelines, a digital ultrasonic test platform known as SONOCHEK was designed. In particular, the leakage of pressurized air and gas equipment can be very expensive, because more electricity is to be extracted to account for the failure. The frequency of detection is inaudible to human beings and varies from 20 to 100 kHz. Nevertheless, they are easily sensed by SONOCHEK, which is integrated into a complete study, making them audible and noticeable when determining the leakage and assessing the overall amount of damage. To track the leakage problem and other abnormalities, SONOCHEK was designed with two applications: Sonoleak and Sonolevel. In a various range of product configurations, highly engineered airborne and framework-borne detectors and apparels are accessible. Airborne DBS10 sound detector with three separate horns detects and assesses the leakage, insulation damage, partial discharge in pipes and walls, etc. The framework-borne and temperature detector DBS20 with a magnet adapter and 150 mm waveguide (optional) helps in monitoring the ultrasound waves generated by spinning machine parts e.g., gears, tracking of flow conditions. Parabolic detectors help in tracking leakage up to 25 m. A DBT10 ultrasonic emitter can be used to conduct air infiltration tests on windows, doors, and containers. Sometimes, it is used in the building projects of ships and airplanes, rail, and road means of transport. The signal amplitude can be changed based on the sound quality of the environment.