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Ferens K.,University of Manitoba | Cook D.,Bristol Aerospace Ltd | Kinsner W.,University of Manitoba
Proceedings of the 12th IEEE International Conference on Cognitive Informatics and Cognitive Computing, ICCI*CC 2013 | Year: 2013

Two different variations of chaotic simulated annealing were applied to combinatorial optimization problems in multiprocessor task allocation. Chaotic walks in the solution space were taken to search for the global optimum or "good enough" task-to-processor allocation solutions. Chaotic variables were generated to set the number of perturbations made in each iteration of a chaotic simulated annealing algorithm. In addition, parameters of a chaotic variable generator were adjusted to create different chaotic distributions with which to search the solution space. The results show a faster convergence time than conventional simulated annealing when the solutions are far apart in the solution space. © 2013 IEEE. Source


Norri K.D.,Bristol Aerospace Ltd | Le Neal R.,Bristol Aerospace Ltd
International Journal of Energetic Materials and Chemical Propulsion | Year: 2014

Bristol manufactures several small solid propellant rocket motors using a composite HTPB/AP based propellant system. Most Bristol rocket motors developed prior to 1990 used an internal insulation system consisting of an asbestos-filled roll-form butadiene (RF/B) case insulation material, with an aluminum liner between the propellant and the insulation. Due to health and safety regulations, processing of asbestos containing insulation materials is no longer permissible. The RF/B insulation system has been replaced with alternate insulation systems which use a Bristol proprietary carbonfilled (CF/P) liner to interface with the propellant. The CF/P liner uses the same polymer system as the propellant, and provides limited insulating capabilities as well as promoting case bonding of the propellant. Motors using the CF/P liner system have shown an augmentation in the propellant burning rate prior to motor tail-off compared to their previous RF/B insulated versions. The performance changes are attributed to a localized augmentation of the propellant burning rate adjacent to the CF/P liner interface. This paper will discuss potential mechanisms for the burning rate augmentation effect, and describes the results of testing and analyses performed to evaluate the phenomenon. © 2014 by Begell House, Inc. Source


Hewson J.,Bristol Aerospace Ltd | Le Neal R.,Bristol Aerospace Ltd
International Journal of Energetic Materials and Chemical Propulsion | Year: 2013

During curing of composite solid rocket motor propellants, the propellant polymer tends to accumulate as a thin film adjacent to the mandrel used to form the internal bore of the propellant grain. This binder-rich layer coats the ammonium perchlorate crystals on the propellant surface and may inhibit flame propagation during rocket motor ignition. Poor flame propagation during ignition can affect both ignition performance and the reliability characteristics. Abrasion of the solid propellant bore surfaces to remove the binder-rich layer and expose the ammonium perchlorate oxidizer is a common procedure used to enhance rocket motor ignition. Abrasion of the propellant bore was evaluated as a means to enhance the ignition performance and reliability characteristics of Bristol 2.75-in. CRV7 rocket motors. Techniques were developed using wire brushes to scrub the surface of the propellant bore. Automated production processes were developed to provide uniform abrasion of the propellant surface, resulting in consistent enhancement of the rocket motor ignition characteristics. This paper describes the development of the CRV7 propellant bore abrasion process, and describes the results of the testing performed to quantify the effect of propellant abrasion on the rocket motor ignition characteristics. © 2013 by Begell House, Inc. Source


Labib M.,Canadian Space Agency | Piontek D.,Canadian Space Agency | Valsecchi N.,Canadian Space Agency | Griffith B.,Canadian Space Agency | And 7 more authors.
SpaceOps 2010 Conference | Year: 2010

The Microgravity Vibration Isolation Subsystem (MVIS), integrated within the European Space Agency's Fluid Science Laboratory (FSL) inside the Columbus Laboratory, was delivered to the International Space Station in February 2008. MVIS is designed to actively isolate vibrations with closed loop control for experiments in the FSL's Facility Core Element (FCE) by monitoring acceleration levels and compensating for them using Lorentz force actuator assemblies. The objectives of this paper are to discuss the rationale for developing MVIS technology, provide an overview of its features, integration and operational concept, update the operations community with its commissioning status, and provide information to experiment developers such that the benefits of MVIS can be maximized. MVIS commissioning Phase 1 was completed in January 2010 with MVIS team support at the FSL Facility Responsible Centre at the Microgravity Advanced Research and Support (MARS) centre along with support from the Canadian Space Agency's (CSA) Payload Telescience Operations Centre. The MVIS hardware is functioning nominally and MVIS centered the FCE with closed loop control and provided measurable vibration attenuation. Preparations are underway for Phase 2 during which time MVIS isolation performance will be tested. Phase 3 will identify an experiment's impact on the system (e.g. configuration, front FCE umbilicals) and assess the fully integrated isolation performance. Since the MVIS isolation performance and operational envelope are directly related to umbilical characteristics, umbilical design recommendations and best practices for experiment developers are provided. The completion of Phase 1 is the culmination of many years of hard work by the large number of individuals who have participated in this program. There continues to be an excellent working relationship between CSA, Bristol Aerospace Limited, ESA, MARS, and Thales Alenia Space. The success of Phase 1 activities paves the way towards future MVIS commissioning activities and routine operations. © 2010 by Government of Canada. Published by the American Institute of Aeronautics and Astronautics, Inc. Source

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