On the Design, Development, and Calibration of a 3D-Printed Implantable Diaphragmatic Hernia Sensor for Livestock
摘要
Microstrip patch antenna-based sensors have recently been explored for livestock health monitoring. However, little has been reported on the design and development of a laboratory-scale test rig to calibrate sensors required for health monitoring of livestock after postoperative diaphragmatic hernia (DH) surgery. In this study, an experimental setup and test rig have been developed to simulate the increase in intra-abdominal pressure exerted by the growing fetus on the bovine diaphragm. The test rig for in vitro analysis contains a reciprocating hydraulic pressure pump (equipped with a digital pressure gauge) for controlling the pressure in the diaphragm. Primarily, the biosensor has been designed and simulated in the Ansys mechanical and high-frequency structural simulator for six pressure values (0-10 kPa), to mimic the growth of the fetus at different stages of pregnancy. The radio-frequency parameters (scattering (S)-parameters, gain, and radiation efficiency) have been recorded for each pressure value. The shift in resonant frequency (fr) has been analyzed in correlation with the material’s change in dielectric constant (εr). Furthermore, to validate the simulated results, a fatigue analysis was performed on the actual buffalo diaphragm’s cut sample by applying a fixed load for several cycles in six different cases. A morphological investigation was also carried out on the deformed samples. To analyze the sensing characteristics, the sensor was tested on a vector network analyzer while sutured to the top of the diaphragm and covered with butyl rubber simultaneously. The shift in S-parameters was recorded over a range of frequencies for six different pressure values. Since the sensor is to be mounted over the diaphragm, its change in εr provides the knowledge of severe conditions before the recurrence of the DH, and the patient can be provided with early medical assistance.