PPT Development for Nanosatellite Applications: Experimental Results
In this paper, the design and performances of a pulsed plasma thruster (PPT) for nanosatellite applications will be presented. The breadboard model PPT presented in this paper will be a part of six PPTs propulsion system designed to provide attitude and translational control for a 20-kg nanosatellite for a total delta-V of 40 m/s. The thruster performances have been characterized in terms of electrical parameters, mass bit, impulse bit, and specific impulse. The thruster was found to be compliant with the mission requirement. Moreover, preliminary electromagnetic noise interference measurements have been performed. The spark plug discharge was found to be the main source of noise as already found by previous authors. From the collected data, it can be inferred that the noise is mostly radiated.
Electromagnetic Emission of Pulsed Plasma Thrusters
This paper deals with the measurement of characteristics of electromagnetic emission of electric propulsions as applied to the EMC problems. Electric propulsion systems on the basis of pulsed plasma thrusters, which are used for the orbit correction of small satellites, are considered as the sources of unintended noise of artificial origin. Test results for the spectral characteristics of emission for the PPT model with the discharge energy of 50 J obtained under ground conditions and their discussion are presented in this paper.
CMEOC—An expert system in the coal mining industry
Abstract This paper introduces an expert system in the mining industry, called the Coal Mining Expert and Optimization Consultation System (CMEOC). The paper mainly describes the architecture of this system, including the knowledge base, inference engine, and relevant optimization techniques. The techniques include multi-objective programming, fuzzy sets, and integer programming. The application results present evidence of the usefulness of the system.