Accidents on gas pipelines cause significant damage to the national economy and the economy of the state. Thus, it is necessary to always be prepared for such situations in order to restore the normal operation of the gas pipeline as soon as possible. An important role is played by the execution time of the control actions to localize the accident, pump out the gas, and change the operating modes. It is essential that such control be undertaken, especially if such a situation occurs near a gas-measuring installation for measuring the amount of vented gas. Therefore, the control actions must be error-free in order to quickly stop the non-stationary process, which can lead to undesirable consequences. The paper presents a mathematical model of the operation of the pipeline, developed for the management of the pipeline in an emergency. The analysis of the problem of the occurrence of accidents was carried out, and the effect of liquid on its walls was modeled when the operating mode of the pipeline changed. An example is presented using a numerical model carried out in ANSYS, as well as being analyzed analytically. The results of the calculations are presented, and special attention is paid to the parameters influencing the change in the operating mode of the pipeline.

This paper presents a design and control of one- wheel type hybrid wheelchair which is operated by the manual power and electric power together. The proposed hybrid wheelchair uses motorized one wheel for the manual wheelchair to supply the assistant power. The proposed one-wheel type hybrid wheelchair uses a BLDC(Brushless DC) motor, and the motorized part can be easily attachable and detachable from the conventional manual wheelchair. In this paper, an indirect estimation for PAS(Power Assistant System) is proposed. The user requirement for the moving of the wheelchair is estimated by the acceleration sensor. A novel estimation factor of the user action is presented, then the reference torque for the assistant power motor is determined by the proposed factor. The detailed design and analysis of the proposed hybrid wheelchair are detailed presented with the simulation and experimental results.