Variable structure controller for plastic injection moulding system

This paper discusses the approach to design of combined ANN and PID temperature controller for a plastic injection moulding system. The proposed method is based on integration of a conventional PID (PI) controller and a multilayer ANN. At the initial stage of operation, the ANN is trained in offline mode to approximately identify the dynamic parameters of the regulator optimised in terms of speed of response and overshoot. Under routine operation mode the ANN control structure is responsible for the fast transients whereas PID (PI) controller provides the high accuracy at the steady state condition. The paper focuses on the structure switching mechanism and the influence on the transient accuracy. In order to verify the proposed approach, the control system having various types of heaters has been modelled and simulated in Matlab/Simulink. The data obtained from the experiment verified the developed model and confirmed the results of simulations

Thermal and Catalytic Cracking of JP-10 for Pulse Detonation Engine Applications

Practical air-breathing pulse detonation engines (PDE) will be based on storable liquid hydrocarbon fuels such as JP-10 or Jet A. However, such fuels are not optimal for PDE operation due to the high energy input required for direct initiation of a detonation and the long deflagration-to-detonation transition times associated with low-energy initiators. These effects increase cycle time and reduce time-averaged thrust, resulting in a significant loss of performance. In an effort to utilize such conventional liquid fuels and still maintain the performance of the lighter and more sensitive hydrocarbon fuels, various fuel modification schemes such as thermal and catalytic cracking have been investigated. We have examined the decomposition of JP-10 through thermal and catalytic cracking mechanisms at elevated temperatures using a bench-top reactor system. The system has the capability to vaporize liquid fuel at precise flowrates while maintaining the flow path at elevated temperatures and pressures for extended periods of time. The catalytic cracking tests were completed utilizing common industrial zeolite catalysts installed in the reactor. A gas chromatograph with a capillary column and flame ionization detector, connected to the reactor output, is used to speciate the reaction products. The conversion rate and product compositions were determined as functions of the fuel metering rate, reactor temperature, system backpressure, and zeolite type. An additional study was carried out to evaluate the feasibility of using pre-mixed rich combustion to partially oxidize JP-10. A mixture of partially oxidized products was initially obtained by rich combustion in JP-10 and air mixtures for equivalence ratios between 1 and 5. Following the first burn, air was added to the products, creating an equivalent stoichiometric mixture. A second burn was then carried out. Pressure histories and schlieren video images were recorded for both burns. The results were analyzed by comparing the peak and final pressures to idealized thermodynamic predictions

Advances in HOSM Control Design and Implementation for PEM Fuel Cell Systems

A second order sliding mode strategy to control the air supply and oxygen stoichiometry of a fuel cell based generation system is presented. The control design is accomplished from a complete model of a experimental plant that was previously developed by the authors and specially suited for nonlinear control issues. The resulting controller endows the system with enhanced dynamic characteristics and robustness to model uncertainties and external disturbances. Simulations and experimental results are provided, showing the feasibility and reliability of the approach.Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señale

Advances in HOSM Control Design and Implementation for PEM Fuel Cell Systems

A second order sliding mode strategy to control the air supply and oxygen stoichiometry of a fuel cell based generation system is presented. The control design is accomplished from a complete model of a experimental plant that was previously developed by the authors and specially suited for nonlinear control issues. The resulting controller endows the system with enhanced dynamic characteristics and robustness to model uncertainties and external disturbances. Simulations and experimental results are provided, showing the feasibility and reliability of the approach.Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señale

Nucleate Pool Boiling Heat Transfer of Refrigerants Using Coated Surfaces

This work presents the experimental study of nucleated pool boiling heat transfer of R-134a and R-410A on a horizontal coated heating surface. The heating surface dimensions are 25.4 mm outer diameter and 116 mm effective length. The coated surfaces were fabricated by flame spraying technique. The copper powder was used as a coating material applied to the outer surface of copper tube. The experiments were performed for heat flux range of 5–50 kWm−2 at saturation temperature of 10°C. The heat transfer coefficients of both refrigerants demonstrated the same trends with applied heat flux increase and their magnitudes increases with increasing the value of applied heat flux. The present study also includes the effects of heat flux and coating parameter on boiling characteristics. The boiling heat transfer coefficient is enhanced by 1.9 times that of plain surface. An empirical correlation was also developed to predict the heat transfer coefficient with a mean error of 13%

A gain-scheduled LPV control for oxygen stoichiometry regulation in PEM fuel cell systems

The article addresses the LPV control of a Polymer Electrolyte Membrane Fuel Cell (PEMFC). In order to optimize efficiency, PEMFCs require reliable control systems ensuring stability and performance, as well as robustness to model uncertainties and external perturbations. On the other hand, PEMFCs present a highly nonlinear behavior that demands nonlinear and/or adaptive control strategies to achieve high performance in the entire operating range. Here, a linear parameter varying (LPV) gain scheduled control is proposed. The control is based on a piecewise affine LPV representation of the PEMFC, a model that can be available in practice. In order to deal with the saturation of the control action, an LPV anti-windup compensation is also proposed. The complete control strategy is applied to several experimental practical situations in a laboratory fuel cell system to evaluate its performance and the reliability of the proposed algorithms.The research of F.D. Bianchi was supported by the European Regional Development Funds (ERDF, FEDER Programa Competitivitat de Catalunya 2007-2013). The research of C. Kunusch has been supported by the Seventh Framework Programme of the European Community through the Marie Curie actions (GA: PCIG09-GA-2011-293876) and project Puma-Mind (GA: FCH-JU-2011-1-303419), as well as by the CICYT project DPI2011-25649 (MICINN-Spain). The research of C. Ocampo-Martinez has been supported by the project MACPERCON (Ref. 201250E027) of the CSIC. The research of R.S. Sánchez Peña has been supported by CONICET and grant PICT2008-290 from the PRH Program of the Ministry of Science, Technology and Innovation of Argentina.Peer Reviewe

Design and realization of a sputter deposition system for the \textit{in situ-} and \textit{in operando-}use in polarized neutron reflectometry experiments

We report on the realization of a sputter deposition system for the in situ- and in operando-use in polarized neutron reflectometry experiments. Starting with the scientific requirements, which define the general design considerations, the external limitations and boundaries imposed by the available space at a neutron beamline and by the neutron and vacuum compatibility of the used materials, are assessed. The relevant aspects are then accounted for in the realization of our highly mobile deposition system, which was designed with a focus on a quick and simple installation and removability at the beamline. Apart from the general design, the in-vacuum components, the auxiliary equipment and the remote control via a computer, as well as relevant safety aspects are presented in detail.Comment: Submitted for publication in Nuclear Inst. and Methods in Physics Research, A. (1st revised version

Magseal Leak Testing Device

Magnetic Seal Corp. has forged a reputable name for itself in the high performance seal industry. Despite great manufacturing practices and product quality, they strive to be even better. Their focus on product quality and cost efficiency lead them to the realization that understanding and fully characterizing porosity in their products was crucial. Due to the nature of the casting process, their magnetic housings inherently have some porosity. Despite thorough inspections upon receiving parts form vendors, porosity can, and often does appear below the surface after parts are machined. As such, a thorough understanding of how porosity effects leakage rates in their parts became essential in order to keep uphold the quality of manufactured parts and more accurately quantify their performance with respect to the standard. The Leakseekers were tasked with designing, manufacturing, and implementing a test rig capable of two things, namely isolating leakage to just the O-Ring - Seal interface, and accurately measuring any leakage past this interface. The information provided by the rig would effectively allow Magseal to more precisely determine the allowable limits of porosity on surfaces of interest, and in so-doing limit the amount of parts discarded due to a broad spectrum that determines whether a part fails inspection or not. Through the use of Financial Analysis, Engineering Analysis and tools like QDF, the team developed a modular design that, with the use of different adapters for different seals, could test a wide range of Magseal products. For optimal utility, the rig was designed with the capability of running 100 hour tests and adapting to multiple seal sizes. Heat, insulation, and pressure sub-systems were also used to ensure that the desired test parameters remained constant throughout the course of a test. An Arduino breadboard was programmed to control and regulate temperatures while an analog pressure system was employed to ensure the desired pressure. In addition to the rig, test and operation procedures, a maintenance manual, electrical system wiring diagrams, a pressure system diagram, and all final assembly CAD part and drawing files were given to the sponsor as deliverables

Conceptual design of an orbital propellant transfer experiment. Volume 2: Study results

The OTV configurations, operations and requirements planned for the period from the 1980's to the 1990's were reviewed and a propellant transfer experiment was designed that would support the needs of these advanced OTV operational concepts. An overall integrated propellant management technology plan for all NASA centers was developed. The preliminary cost estimate (for planning purposes only) is $56.7 M, of which approximately$31.8 M is for shuttle user costs