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52nd IEEE Annual conference on Decision and control (CDC)

作者： Abeykoon, Chamil Kelly, Adrian L. Martin, Peter J. Li, Kang Univ Bradford Sch Engn Design & Technol Bradford BD7 1DP W Yorkshire England Queens Univ Belfast Sch Mech & Aerosp Engn Belfast BT9 5AH Antrim North Ireland Queens Univ Belfast Sch Elect Elect Engn & Comp Sci Belfast BT9 5AH Antrim North Ireland

ISBN: (纸本)9781467357173

The extrusion process is one of the main methods of processing polymeric materials and thermal homogeneity of the process output presents a major challenge for high quality extruded products. Therefore, accurate process thermal monitoring and control are highly desirable. However, most of the industrial extruders use conventional single point thermocouples for thermal monitoring although their measurements are highly affected by barrel metal wall temperature. Moreover, it has been shown that the melt temperature changes considerably with the die radial position and point based measurements are not sufficient to determine the actual process thermal stability and hence to control the thermal homogeneity of melt output. Conversely, the majority of process thermal control methods are based on linear models and are not capable of dealing with process nonlinearities. In this work, a die melt temperature profile was monitored by a thermocouple mesh technique and the data obtained was used to formulate a new nonlinear dynamic model to predict the die melt temperature profile in a single screw extruder. The model is in good agreement with the measured data and offers a promising thermal monitoring technique which can be used in real-time for a thermal profile based control framework in polymer extrusion.

关键词： polymer extrusion Process monitoring Thermal homogeneity Melt temperature profile System identification Dynamic modelling

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Flow property measurements for nanoimprint simulation

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MICROELECTRONIC ENGINEERING 2007年第5-8期84卷 928-931页

作者： Leveder, T. Landis, S. Davoust, L. Chaix, N. CEA Leti Minatec F-38054 Grenoble France LEGI ENSHMG F-38041 Grenoble France CNRS LTM F-38054 Grenoble 9 France

Number of recent works report that viscoelastic properties of ultra-thin polymer film (below 100 nm) could drastically change from bulk values, deeply impacting nanoimprint process simulation. A good knowledge of thin resist film viscosity is thus needed, either for UV imprint, or thermal imprint. Nanoimprint lithography has been used to characterize sub 100 nm resist film flow properties above glass transition temperature. Specifically designed stamps have been manufactured to control silicon etched lines motion into the melt polymer. Adapted fluid modelling is proposed to calculate dynamic viscosity of thin polymer film for different temperatures from experimental data. Good agreements between ours results and literature were found. (c) 2007 Elsevier B.V. All rights reserved.

关键词： nanoimprint lithography thermal imprint flow properties

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Time-domain spectral element method for modelling of the electromechanical impedance of disbonded composites

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JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES 2018年第16期29卷 3214-3221页

作者： Fiborek, Piotr Malinowski, Pawel H. Kudela, Pawel Wandowski, Tomasz Ostachowicz, Wieslaw M. Polish Acad Sci Inst Fluid Flow Machinery 14 Fiszera St PL-80231 Gdansk Poland

The research focuses on the electromechanical impedance method. The electromechanical impedance method can be treated as non-destructive testing or structural health monitoring approach. It is important to have a reliable tool that allows verifying the integrity of the investigated objects. The electromechanical impedance method was applied here to assess the carbon fibre-reinforced polymer samples. The single and adhesively bonded samples were investigated. In the reported research, the electromechanical impedance spectra up to 5 MHz were considered. The investigation comprised of modelling using spectral element method and experimental measurements. Numerical and experimental spectra were analysed. Differences in spectra caused by differences in considered samples were observed.

关键词： Electromechanical impedance time-domain spectral element method carbon fibre-reinforced polymer

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Integration of processing models with control and optimization of polymer composites fabrication

Integration of processing models with control and optimizati...

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3rd International conference on Computer Aided Design in Composite Material Technology - CADCOMP 92

作者： Kenny, J.M. Univ of Naples Naples Italy

ISBN: (纸本)1853121665

Processing of polymer matrix composites is always associated with strong modifications of the polymeric structure. In the case of thermosetting matrices the fabrication process involves polymerization reactions which are responsible for the evolution of the polymer structure and viscosity. Several studies have been developed in the past to model changes of material properties during the processing of polymer composites. These attempts also include heat and momentum transfer operations for different processing technologies like autoclave lamination, pultrusion, filament winding, compression molding and resin transfer molding. In this work recent results on the modelling of the evolution of polymeric matrix properties during processing are presented. Moreover, the modelling strategy is integrated with temperature monitoring procedures allowing control and optimization of the process. The intelligent system developed specifically for autoclave lamination allows the computation in real time of heat transfer coefficients for each selected tool, the prediction of temperature changes inside the laminate as a function of the programmed air temperature and the optimization of the cure cycle minimizing the difference between the actual temperature and the value recommended by process specifications, minimizing also the processing time.

关键词： polymers

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Electrochemical oxidation of polypyrrole under conformational relaxation control. Electrochemical relaxation model

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SYNTHETIC METALS 1996年第1-3期76卷 285-288页

作者： Otero, TF Grande, H Rodriguez, J Universidad del País Vasco Facultad de Química Laboratorio de Electroquímica PO Box 1072 20080 San Sebastián Spain

A simple model of polymeric relaxation, associated with the electrochemical switching of polypyrrole films between their reduced (insulating) and oxidized (electronically conducting) states, offers a reasonably precise description of the form of chronoamperograms obtained after previous submission of the polymer film to cathodic potentials (which control the compactness of the neutral polymer) for long periods of time. Opening of the structure driven by anodic potential is not uniform: nucleation of conducting zones inside the neutral polymer and their overlap at long times of anodic polarization are taken into account in the model. Diffusion of counterions from the solution across the oxidized zones are also included. The definition of a relaxation time (depending on both cathodic and anodic overpotentials), and the inclusion of nucleation and diffusion processes, allows a theoretical modelling of chronoamperograms in good agreement with experimental data. This electrochemical relaxation theory is an open model including both electrochemical and polymeric magnitudes.

关键词： electrochemical oxidation polypyrrole relaxation models

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monitoring and modelling of the Energy Consumption in polymer Extrusion 13

Monitoring and Modelling of the Energy Consumption in Polyme...

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13th European control conference (ECC)

作者： Abeykoon, Chamil Kelly, Adrian L. Vera-Sorroche, Javier Brown, Elaine C. Coates, Phil D. Glyndwr Univ Sch Engn & Appl Phys Wrexham LL11 2AW Wales Univ Bradford IRC Polymer Sci & Technol Bradford BD7 1DP W Yorkshire England

ISBN: (纸本)9783952426913

Extrusion is one of the fundamental methods in polymer processing and is involved in the production of various commodities in diverse industrial sectors. Being an energy intensive production method, process energy efficiency is one of the major concerns and the selection of the most energy efficient processing conditions is a key to reduce operating expenses. Usually, extruders consume energy through the drive motor, barrel heaters, cooling fans, cooling water pumps, gear pumps, etc. Typically the drive motor is the dominant energy consuming device in a polymer processing extruder while barrel/die heaters are responsible for the second largest energy demand. This study was focused on investigating the total energy demand of an extrusion plant while identifying ways to optimise the energy consumption. Total energy consumption of a single screw extruder was measured over different processing conditions and then modelled as a function of a number of major process variables. The results show that the extruder energy demand is heavily coupled with machine, material and process parameters. Also, the proposed models show excellent agreement with the experimental measurements and hence these should be useful in optimising process energy efficiency.

关键词： polymer extrusion Process monitoring Energy consumption Energy efficiency Power factor modelling

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Vibrational spectroscopic investigation of polymer melt processing

Vibrational spectroscopic investigation of polymer melt proc...

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作者： Lalehvash Moghaddam Queensland University of Technology

学位级别：博士

A polymer is rarely used as a pure material and the baseline physical, chemical and rheological properties such as molecular weight, strength, stiffness and viscosity are often modified by the addition of fillers or by blending with another polymer. However, as many polymers are immiscible, compatibilisation and graft processing polymer blends are very important techniques to increase miscibility of the blends as well as to improve chemical, physical and mechanical properties. Reactive extrusion, or melt-state processing, is one of the most appropriate techniques for improving polymer properties. Compatibilisation and graft polymer processing are often carried out under reactive extrusion conditions. This technique is an efficient approach because it is easy, inexpensive and has a short processing time. Although reactive extrusion has numerous advantages one of the limitations is degradation of the polymer under the high temperatures and mechanical stresses encountered. In the polymer industry, because of increasing customer demand for improved product quality, optimising the polymerisation process by decreasing product costs and controlling the reaction during polymerisation has become more important. It can be said that any method used for monitoring the polymerisation process has to be fast, accurate and reliable. Both in-line and on-line methods may be involved in in- process monitoring. The primary information from in-process monitoring is used for identifying and understanding molecular structure and changes, optimising and improving process modelling and understanding whether the process is under control. This also involves considering whether the products have the required properties. This thesis describes research in a number of aspects of melt processing of polymers, including examination of extruded products, an in situ spectroscopic study of the reaction of MAH and PP, a study of the melt processing of TPU, and a study of the use of nitroxide radicals as

关键词： vibrational spectroscopy polymer melt processing

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Multivariate analysis models for wood properties combined with Open Modelica model for process performance monitoring 8

Multivariate analysis models for wood properties combined wi...

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8th Vienna International conference on Mathematical modelling

作者： Skvaril, Jan Kyprianidis, Konstantinos Avelin, Anders Odlare, Monica Dahlquist, Erik Malardalen Univ Sch Business Soc & Engn Hogskoleplan 1 Vasteras 72123 Sweden

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A review of electrical conductivity models for conductive polymer composite

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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 2017年第14期42卷 9262-9273页

作者： Radzuan, Nabilah Afiqah Mohd Sulong, Abu Bakar Sahari, Jaafar Univ Kebangsaan Malaysia Fuel Cell Inst Ukm Bangi 43600 Selangor Malaysia Univ Kebangsaan Malaysia Dept Mech & Mat Engn Ukm Bangi 43600 Selangor Malaysia

Conductive polymer Composite (CPC) can be considered one of the best material candidates for the bipolar plates in polymer Electrolyte Membrane (PEM) fuel cells due to its balance between electrical and mechanical properties, low cost and ease of manufacturing. The development of the models has been shown to be important for predicting the electrical properties of the CPCs. The main challenge is to produce a constant electric supply in the fuel cell systems which influence the overall fuel cell performance. Generally, the classical percolation theory describes that the electrical conductivity of the polymer composite is achieved when the volume fraction of the conductive filler is above the specific value, known as percolation threshold phenomena. Current research trends using the General Effective Media (GEM) model show it is the best model to predict the electrical properties of the composite. The main advantage of using the GEM is the model can predict the electrical conductivity for multiple filler systems at high filler loadings. Numerous factors including volume fraction, shape and size, aspect ratio, critical value, and orientation are significant in developing a robust model. controlling the filler orientations in the CPCs are important as they are able to improve the mechanical performance while enhancing the electrical conductivity of the composite. Orientation can be induced by a few methods such as shear stress, altering die and fillers aspect ratio based on the needs. By controlling the fillers direction, one is able to control both the mechanical and electrical conductivity of the CPCs. However, recent publications seem to suggest that the Fibre Contact Model (FCM) is the latest model that considers the orientation factor in predicting conductivity. A good agreement between experimental results and modelling prediction can be observed using carbon-fibre reinforced polypropylene below and above the percolation threshold. Parallel orientations of the fib

关键词： Electrical conductivity Model conductivity polymer composite Composite bipolar plate polymer electrolyte membrane fuel cell

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Special requirements of the flow system and equipment for viscoelastic polgmer fluids

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JOURNAL OF PETROLEUM TECHNOLOGY 2002年第12期54卷 54-+页

作者： [Anonymous] JPT Technology Editor

Most flow systems and equipment for the injection, production, and gathering of large amounts of fluid are designed for Newtonian fluids. Now, an increasing number of oil fields are on viscoelastic polyacrylamide (PAM) flooding. after flooding, the flow of this type of fluid through production and surface systems and equipment had characteristics that require special design for the equipment and flow process to preserve service life.

关键词： viscoelastic polymer fluid drilling fluids and materials drilling fluid selection and formulation branch line pam fluid viscosity modification artificial lift system production logging production control Artificial Lift Systems Beam and related pumping techniques Drilling fluid selection and formulation (chemistry properties) Drilling Fluids and Materials Improved and Enhanced Recovery Production logging Well & Reservoir Surveillance and monitoring

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