A Computational Channel Model for Magnetic Induction-Based Subsurface Applications

There are many underground applications based on magnetic fields generated by an oscillating magnetic source. For them, a magnetic dipole in a three-layered region with upper semi-infinite air layer can be a convenient idealization used for their planning, development, and operation. Solutions are in the form of the well-known Sommerfeld integral expressions that can be evaluated by numerical methods. A set of field expressions to be numerically evaluated by an efficient algorithm are not collected comprehensively yet, or at least in a directly usable form. In this paper, the explicit magnetic field solutions for the vertical magnetic dipole and the horizontal magnetic dipole for a general source-observer location are derived from the Hertz vector. They can be properly combined to model the problem of a tilted magnetic dipole source for horizontally or inclined stratified media. As a result, a complete set of integral equations of the Sommerfeld type valid from the near zone to the far zone are formulated. A method for numerical evaluation of the field expressions for high accurate computations is described. The numerical results are validated using the finite element method for all the possible source-receiver configurations and three well-spanned frequencies of typical subsurface applications. Both numerical solutions agree according to the normalized root-mean-square error-based fit metric. Numerical results for two cases of study are presented to see its usefulness for subsurface applications. A MATLAB implementation of the mathematical description outlined in this paper and the proposed evaluation method is freely available for download

A Robot to Measure Water Parameters in Water Distribution Systems

Water distribution systems (WDS) are critical infrastructures that transfer drinking water to consumers. In the U.S., around 42 billion gallons of water are being delivered per day via one million miles of pipes to be used in different sectors. Incidents to pipelines cause leak or let contaminants enter purified water in pipe that is harmful to public health. Hence, periodic condition assessments of pipelines and water inside it are required. However, due to the long and complicated configurations of these networks, access to all parts of the pipelines is a cumbersome task. To this aim, in-pipe robots are promising solution that facilitate access to different locations inside pipelines and perform different in-pipe missions. In this project, we design and fabricate an in-pipe robotic system is that is used for water quality monitoring. The robot is equipped with a wireless sensor module and the sensor module is synchronized with the motion unit of the robot. The wireless sensor module facilitates bi-directional data transmission between the robot and base station aboveground. The integrated robotic system navigates in different configurations of the pipeline with smart motion. To this aim, the mechanical design of the self-powered robot based on three adjustable arm modules and three actuator modules is designed. The components of the robot are characterized based on real operation conditions in pipes. A multi-phase motion control algorithm is developed for the robot to move in straight path and non-straight configurations like bends and T-junctions. A bi-directional wireless sensor module is designed to send data packets through underground environment. Finally, the multi-phase motion controller is synchronized with the wireless sensor module and we propose an operation procedure for the robot. In the operation procedure, some radio transceivers are located at non-straight configurations of pipelines and receive the sensor measurements from the robot and guide the robot in the desired direction. The proposed operation procedure provides smart navigation and data transmission during operation for the robot