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Dr. Marion McAfee
Institute of Technology Sligo, Ireland

Basic Info


Research Keywords & Expertise

0 soft sensors
0 Medical Device Manufacturing
0 Process Monitoring and Control - particularly of polymer processes
0 Process Spectroscopy
0 Process Modelling and Optimisation

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Process Monitoring and Control - particularly of polymer processes

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Short Biography

Dr Marion McAfee was awarded a PhD in Process Control from Queen’s University Belfast in 2005, following an MEng in Mechanical and Manufacturing Engineering from the same Institute. She worked as a postdoctoral researcher in ‘Energy Efficient Extrusion’ following her PhD and was appointed as a Lecturer in Engineering Dynamics and Control at the School of Mechanical and Aerospace Engineering in Queen’s University Belfast in 2006. She is currently a Senior Lecturer in the Department of Mechatronic Engineering at the Institute of Technology Sligo. Her research interests are in sensorization, sensor fusion, modelling and control solutions improve product quality, enhance process efficiency, and reduce waste in manufacturing processes. She has been the Principal Investigator or Co-Principal Investigator on externally funded grants awarded by the EPSRC, Royal Society, EU Framework Programme, SFI and Enterprise Ireland. She has worked with over 20 industrial partners from across Europe on delivering solutions to reduce downtime, reduce energy consumption, improve product quality, and reduce scrap rates on a range of polymer and medical device manufacturing processes. Dr McAfee is a Funded Investigator in the I-Form Advanced Manufacturing Research Centre funded by Science Foundation Ireland (SFI). She became a member of IEEE in 2020.

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Review
Published: 31 July 2021 in Sensors
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Injection moulding is an extremely important industrial process, being one of the most commonly-used plastic formation techniques. However, the industry faces many current challenges associated with demands for greater product customisation, higher precision and, most urgently, a shift towards more sustainable materials and processing. Accurate real-time sensing of the material and part properties during processing is key to achieving rapid process optimisation and set-up, reducing down-times, and reducing waste material and energy in the production of defective products. While most commercial processes rely on point measurements of pressure and temperature, ultrasound transducers represent a non-invasive and non-destructive source of rich information on the mould, the cavity and the polymer melt, and its morphology, which affect critical quality parameters such as shrinkage and warpage. In this paper the relationship between polymer properties and the propagation of ultrasonic waves is described and the application of ultrasound measurements in injection moulding is evaluated. The principles and operation of both conventional and high temperature ultrasound transducers (HTUTs) are reviewed together with their impact on improving the efficiency of the injection moulding process. The benefits and challenges associated with the recent development of sol-gel methods for HTUT fabrication are described together with a synopsis of further research and development needed to ensure a greater industrial uptake of ultrasonic sensing in injection moulding.

ACS Style

Mandana Kariminejad; David Tormey; Saif Huq; Jim Morrison; Marion McAfee. Ultrasound Sensors for Process Monitoring in Injection Moulding. Sensors 2021, 21, 5193 .

AMA Style

Mandana Kariminejad, David Tormey, Saif Huq, Jim Morrison, Marion McAfee. Ultrasound Sensors for Process Monitoring in Injection Moulding. Sensors. 2021; 21 (15):5193.

Chicago/Turabian Style

Mandana Kariminejad; David Tormey; Saif Huq; Jim Morrison; Marion McAfee. 2021. "Ultrasound Sensors for Process Monitoring in Injection Moulding." Sensors 21, no. 15: 5193.

Journal article
Published: 05 May 2021 in International Journal of Molecular Sciences
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In this paper, newly discovered mechanisms of atresia and cell death processes in bovine ovarian follicles are investigated. For this purpose the mRNA expression of receptor interacting protein kinases 1 and 3 (RIPK1 and RIPK3) of the granulosa and theca cells derived from healthy and atretic follicles are studied. The follicles were assigned as either healthy or atretic based on the estradiol to progesterone ratio. A statistically significant difference was recorded for the mRNA expression of a RIPK1 and RIPK3 between granulosa cells from healthy and atretic follicles. To further investigate this result a systems biology approach was used. The genes playing roles in necroptosis, apoptosis and atresia were chosen and a network was created based on human genes annotated by the IMEx database in Cytoscape to identify hubs and bottle-necks. Moreover, correlation networks were built in the Cluepedia plug-in. The networks were created separately for terms describing apoptosis and programmed cell death. We demonstrate that necroptosis (RIPK—dependent cell death pathway) is an alternative mechanism responsible for death of bovine granulosa and theca cells. We conclude that both apoptosis and necroptosis occur in the granulosa cells of dominant follicles undergoing luteinisation and in the theca cells from newly selected follicles.

ACS Style

Malgorzata McEvoy; Emilia Sinderewicz; Leo Creedon; Marion McAfee; Agnieszka Jonczyk; Katarzyna Piotrowska-Tomala; Dariusz Skarzynski. Death Processes in Bovine Theca and Granulosa Cells Modelled and Analysed Using a Systems Biology Approach. International Journal of Molecular Sciences 2021, 22, 4888 .

AMA Style

Malgorzata McEvoy, Emilia Sinderewicz, Leo Creedon, Marion McAfee, Agnieszka Jonczyk, Katarzyna Piotrowska-Tomala, Dariusz Skarzynski. Death Processes in Bovine Theca and Granulosa Cells Modelled and Analysed Using a Systems Biology Approach. International Journal of Molecular Sciences. 2021; 22 (9):4888.

Chicago/Turabian Style

Malgorzata McEvoy; Emilia Sinderewicz; Leo Creedon; Marion McAfee; Agnieszka Jonczyk; Katarzyna Piotrowska-Tomala; Dariusz Skarzynski. 2021. "Death Processes in Bovine Theca and Granulosa Cells Modelled and Analysed Using a Systems Biology Approach." International Journal of Molecular Sciences 22, no. 9: 4888.

Journal article
Published: 31 March 2021 in Chemosensors
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Electrospun nanofibrous mats consisting of chitosan (CS) and polyvinylpyrrolidone (PVP) were constructed. Tuning of solution and process parameters was performed and resulted in an electrospun system containing a 6:4 ratio of PVP:CS. This is a significant increase in the proportion of spun CS on the previously reported highest ratio PVP:CS blend. SEM analysis showed that the nanofibrous mats with 4 wt% CS/6 wt% PVP (sample E) comprised homogenous, uniform fibres with an average diameter of 0.569 μm. XPS analysis showed that the surface of the samples consisted of PVP. Raman and FTIR analysis revealed intermolecular interactions (via H-bonding) between PVP and CS. In FTIR spectra, the contribution of chitosan to CS/PVP complexes was shown by the downshift of the C=O band and by the linear increase in intensity of C-O stretching in CS. XPS analysis showed a smaller shift at the binding energy 531 eV, which relates to the amide of the acetylated functional groups. The obtained results demonstrate a sensitivity of Raman and FTIR tests to the presence of chitosan in PVP:CS blend. The chemotherapy drug 5-Fu was incorporated into the constructs and cell viability studies were performed. WST-8 viability assay showed that exposure of A549 human alveolar basal epithelial cells to 10 mg/mL 5-Fu loaded fibres was most effective at killing cells over 24 h. On the other hand, the constructs with loading of 1 mg/mL of drug were not efficient at killing A549 human alveolar basal epithelial cells. This study showed that CS/PVP/5-Fu constructs have potential in chemotherapeutic drug delivery systems.

ACS Style

Jamie Grant; Suresh Pillai; Tatiana Perova; Sarah Hehir; Steven Hinder; Marion McAfee; Ailish Breen. Electrospun Fibres of Chitosan/PVP for the Effective Chemotherapeutic Drug Delivery of 5-Fluorouracil. Chemosensors 2021, 9, 70 .

AMA Style

Jamie Grant, Suresh Pillai, Tatiana Perova, Sarah Hehir, Steven Hinder, Marion McAfee, Ailish Breen. Electrospun Fibres of Chitosan/PVP for the Effective Chemotherapeutic Drug Delivery of 5-Fluorouracil. Chemosensors. 2021; 9 (4):70.

Chicago/Turabian Style

Jamie Grant; Suresh Pillai; Tatiana Perova; Sarah Hehir; Steven Hinder; Marion McAfee; Ailish Breen. 2021. "Electrospun Fibres of Chitosan/PVP for the Effective Chemotherapeutic Drug Delivery of 5-Fluorouracil." Chemosensors 9, no. 4: 70.

Review article
Published: 17 March 2021 in ACS Biomaterials Science & Engineering
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Graphene oxide (GO) has broad potential in the biomedical sector. The oxygen-abundant nature of GO means the material is hydrophilic and readily dispersible in water. GO has also been known to improve cell proliferation, drug loading, and antimicrobial properties of composites. Electrospun composites likewise have great potential for biomedical applications because they are generally biocompatible and bioresorbable, possess low immune rejection risk, and can mimic the structure of the extracellular matrix. In the current review, GO-containing electrospun composites for tissue engineering applications are described in detail. In addition, electrospun GO-containing materials for their use in drug and gene delivery, wound healing, and biomaterials/medical devices have been examined. Good biocompatibility and anionic-exchange properties of GO make it an ideal candidate for drug and gene delivery systems. Drug/gene delivery applications for electrospun GO composites are described with a number of examples. Various systems using electrospun GO-containing therapeutics have been compared for their potential uses in cancer therapy. Micro- to nanosized electrospun fibers for wound healing applications and antimicrobial applications are explained in detail. Applications of various GO-containing electrospun composite materials for medical device applications are listed. It is concluded that the electrospun GO materials will find a broad range of biomedical applications such as cardiac patches, medical device coatings, sensors, and triboelectric nanogenerators for motion sensing and biosensing.

ACS Style

Jamie J. Grant; Suresh C. Pillai; Sarah Hehir; Marion McAfee; Ailish Breen. Biomedical Applications of Electrospun Graphene Oxide. ACS Biomaterials Science & Engineering 2021, 7, 1278 -1301.

AMA Style

Jamie J. Grant, Suresh C. Pillai, Sarah Hehir, Marion McAfee, Ailish Breen. Biomedical Applications of Electrospun Graphene Oxide. ACS Biomaterials Science & Engineering. 2021; 7 (4):1278-1301.

Chicago/Turabian Style

Jamie J. Grant; Suresh C. Pillai; Sarah Hehir; Marion McAfee; Ailish Breen. 2021. "Biomedical Applications of Electrospun Graphene Oxide." ACS Biomaterials Science & Engineering 7, no. 4: 1278-1301.

Journal article
Published: 01 August 2018 in Polymer Testing
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ACS Style

Konrad Mulrennan; John Donovan; Leo Creedon; Ian Rogers; John G. Lyons; Marion McAfee. A soft sensor for prediction of mechanical properties of extruded PLA sheet using an instrumented slit die and machine learning algorithms. Polymer Testing 2018, 69, 462 -469.

AMA Style

Konrad Mulrennan, John Donovan, Leo Creedon, Ian Rogers, John G. Lyons, Marion McAfee. A soft sensor for prediction of mechanical properties of extruded PLA sheet using an instrumented slit die and machine learning algorithms. Polymer Testing. 2018; 69 ():462-469.

Chicago/Turabian Style

Konrad Mulrennan; John Donovan; Leo Creedon; Ian Rogers; John G. Lyons; Marion McAfee. 2018. "A soft sensor for prediction of mechanical properties of extruded PLA sheet using an instrumented slit die and machine learning algorithms." Polymer Testing 69, no. : 462-469.

Journal article
Published: 01 May 2018 in Polymer Testing
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Determination of the dispersion characteristics/or morphology of additives in polymer melts by fast, reliable and accurate on-line methods is highly desired in the polymer industry. An ultraviolet-visible (UV-Vis) spectroscopic methodology is described which meets these demands. It is demonstrated that the applied methodology may be developed on a cheap, packaging grade of Polylactic Acid (PLLA), an important bioresorbable polymer for the medical device industry, and still be accurate when implemented on a production line using a more expensive (medical) grade of the polymer compound. Simple chemometric algorithms are applied allowing the data processing step to be carried out in near real time, thus providing vital information to process operators which allows any out of control process to be identified and rectified without product loss.

ACS Style

Darren A. Whitaker; Fraser Buchanan; Mark Billham; Marion McAfee. A UV-Vis spectroscopic method for monitoring of additive particle properties during polymer compounding. Polymer Testing 2018, 67, 392 -398.

AMA Style

Darren A. Whitaker, Fraser Buchanan, Mark Billham, Marion McAfee. A UV-Vis spectroscopic method for monitoring of additive particle properties during polymer compounding. Polymer Testing. 2018; 67 ():392-398.

Chicago/Turabian Style

Darren A. Whitaker; Fraser Buchanan; Mark Billham; Marion McAfee. 2018. "A UV-Vis spectroscopic method for monitoring of additive particle properties during polymer compounding." Polymer Testing 67, no. : 392-398.

Conference paper
Published: 01 January 2014 in Communications in Computer and Information Science
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ACS Style

Darren Whitaker; Fraser Buchanan; Domhnall Lennon; Mark Billham; Marion McAfee. The Application of Computational Chemistry and Chemometrics to Developing a Method for Online Monitoring of Polymer Degradation in the Manufacture of Bioresorbable Medical Implants. Communications in Computer and Information Science 2014, 215 -225.

AMA Style

Darren Whitaker, Fraser Buchanan, Domhnall Lennon, Mark Billham, Marion McAfee. The Application of Computational Chemistry and Chemometrics to Developing a Method for Online Monitoring of Polymer Degradation in the Manufacture of Bioresorbable Medical Implants. Communications in Computer and Information Science. 2014; ():215-225.

Chicago/Turabian Style

Darren Whitaker; Fraser Buchanan; Domhnall Lennon; Mark Billham; Marion McAfee. 2014. "The Application of Computational Chemistry and Chemometrics to Developing a Method for Online Monitoring of Polymer Degradation in the Manufacture of Bioresorbable Medical Implants." Communications in Computer and Information Science , no. : 215-225.

Conference paper
Published: 01 September 2012 in Proceedings of 2012 UKACC International Conference on Control
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Polymer extrusion is one of the final forming stages in the production of many polymeric products in a variety of applications. It is also an intermediate processing step in injection moulded, blown film, thermo-formed, and blow moulded products. However, polymer extrusion is a complex process which is difficult to set up, monitor, and control. As a consequence, high levels of off- specification products and long down-times are the problems facing the plastics industry. This paper proposes a new method for fault detection of the polymer extrusion processes, where the nonlinear finite impulse response (NFIR) model and principal component analysis (PCA) are integrated to form a nonlinear dynamic model-based PCA monitoring scheme. Here the NFIR model is used to capture the nonlinearity and dynamics of the extrusion process. The residuals resulting from the difference between the model predicted outputs and process outputs are then analyzed by PCA to detect process faults. The experimental results confirm the efficacy of the proposed model-based PCA approach for fault detection of polymer extrusion processes.

ACS Style

Xueqin Liu; Kang Li; Marion McAfee; Jing Deng. Polymer extrusion process monitoring using nonlinear dynamic model-based PCA. Proceedings of 2012 UKACC International Conference on Control 2012, 7 -12.

AMA Style

Xueqin Liu, Kang Li, Marion McAfee, Jing Deng. Polymer extrusion process monitoring using nonlinear dynamic model-based PCA. Proceedings of 2012 UKACC International Conference on Control. 2012; ():7-12.

Chicago/Turabian Style

Xueqin Liu; Kang Li; Marion McAfee; Jing Deng. 2012. "Polymer extrusion process monitoring using nonlinear dynamic model-based PCA." Proceedings of 2012 UKACC International Conference on Control , no. : 7-12.

Article
Published: 17 February 2012 in Polymer Engineering & Science
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Melt viscosity is a key indicator of product quality in polymer extrusion processes. However, real time monitoring and control of viscosity is difficult to achieve. In this article, a novel “soft sensor” approach based on dynamic gray‐box modeling is proposed. The soft sensor involves a nonlinear finite impulse response model with adaptable linear parameters for real‐time prediction of the melt viscosity based on the process inputs; the model output is then used as an input of a model with a simple‐fixed structure to predict the barrel pressure which can be measured online. Finally, the predicted pressure is compared to the measured value and the corresponding error is used as a feedback signal to correct the viscosity estimate. This novel feedback structure enables the online adaptability of the viscosity model in response to modeling errors and disturbances, hence producing a reliable viscosity estimate. The experimental results on different material/die/extruder confirm the effectiveness of the proposed “soft sensor” method based on dynamic gray‐box modeling for real‐time monitoring and control of polymer extrusion processes. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers

ACS Style

Xueqin Liu; Kang Li; Marion McAfee; Bao Kha Nguyen; Gerard M. McNally. Dynamic gray-box modeling for on-line monitoring of polymer extrusion viscosity. Polymer Engineering & Science 2012, 52, 1332 -1341.

AMA Style

Xueqin Liu, Kang Li, Marion McAfee, Bao Kha Nguyen, Gerard M. McNally. Dynamic gray-box modeling for on-line monitoring of polymer extrusion viscosity. Polymer Engineering & Science. 2012; 52 (6):1332-1341.

Chicago/Turabian Style

Xueqin Liu; Kang Li; Marion McAfee; Bao Kha Nguyen; Gerard M. McNally. 2012. "Dynamic gray-box modeling for on-line monitoring of polymer extrusion viscosity." Polymer Engineering & Science 52, no. 6: 1332-1341.

Journal article
Published: 31 December 2011 in Journal of Materials Processing Technology
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Polymer extrusion is one of the major methods of processing polymer materials and advanced process monitoring is important to ensure good product quality. However, commonly used process monitoring devices, e.g. temperature and pressure sensors, are limited in providing information on process dynamics inside an extruder barrel. Screw load torque dynamics, which may occur due to changes in solids conveying, melting, mixing, melt conveying, etc., are believed to be a useful indicator of process fluctuations inside the extruder barrel. However, practical measurement of the screw load torque is difficult to achieve. In this work, inferential monitoring of the screw load torque signal in an extruder was shown to be possible by monitoring the motor current (armature and/or field) and simulation studies were used to check the accuracy of the proposed method. The ability of this signal to aid identification and diagnosis of process issues was explored through an experimental investigation. Power spectral density and wavelet frequency analysis were implemented together with a covariance analysis. It was shown that the torque signal is dominated by the solid friction in the extruder and hence it did not correlate well with melting fluctuations. However, it is useful for online identification of solids conveying issues.

ACS Style

Chamil Abeykoon; Marion McAfee; Kang Li; Peter J. Martin; Adrian Kelly. The inferential monitoring of screw load torque to predict process fluctuations in polymer extrusion. Journal of Materials Processing Technology 2011, 211, 1907 -1918.

AMA Style

Chamil Abeykoon, Marion McAfee, Kang Li, Peter J. Martin, Adrian Kelly. The inferential monitoring of screw load torque to predict process fluctuations in polymer extrusion. Journal of Materials Processing Technology. 2011; 211 (12):1907-1918.

Chicago/Turabian Style

Chamil Abeykoon; Marion McAfee; Kang Li; Peter J. Martin; Adrian Kelly. 2011. "The inferential monitoring of screw load torque to predict process fluctuations in polymer extrusion." Journal of Materials Processing Technology 211, no. 12: 1907-1918.

Journal article
Published: 30 December 2011 in Polymer Engineering & Science
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The cooling process in conventional rotomolding is relatively long due to poor thermal conductivity of plastics. The lack of internal cooling is a major limitation although rapid external cooling is possible. Various internal cooling methodologies have been studied to reduce the cycle time. These include the use of compressed air, cryogenic liquid nitrogen, chilled water coils, and cryogenic liquid carbon dioxide, all of which have limitations. However, this article demonstrates the use of water spray cooling of polymers as a viable and effective method for internal cooling in rotomolding. To this end, hydraulic, pneumatic, and ultrasonic nozzles were applied and evaluated using a specially constructed test rig to assess their efficiency. The effects of nozzle type and different parametric settings on water droplet size, velocity, and mass flow rate were analyzed and their influence on cooling rate, surface quality, and morphology of polymer exposed to spray cooling were characterized. The pneumatic nozzle provided highest average cooling rate while the hydraulic nozzle gave lowest average cooling rate. The ultrasonic nozzle with medium droplet size traveling at low velocity produced satisfactory surface finish. Water spray cooling produced smaller spherulites compared to ambient cooling whilst increasing the cooling rate decreases the percentage crystallinity. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers

ACS Style

S.B. Tan; P.R. Hornsby; Marion McAfee; M.P. Kearns; M.P. McCourt. Water spray cooling of polymers. Polymer Engineering & Science 2011, 52, 1069 -1080.

AMA Style

S.B. Tan, P.R. Hornsby, Marion McAfee, M.P. Kearns, M.P. McCourt. Water spray cooling of polymers. Polymer Engineering & Science. 2011; 52 (5):1069-1080.

Chicago/Turabian Style

S.B. Tan; P.R. Hornsby; Marion McAfee; M.P. Kearns; M.P. McCourt. 2011. "Water spray cooling of polymers." Polymer Engineering & Science 52, no. 5: 1069-1080.

Journal article
Published: 31 October 2011 in Journal of Process Control
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Nonlinear principal component analysis (PCA) based on neural networks has drawn significant attention as a monitoring tool for complex nonlinear processes, but there remains a difficulty with determining the optimal network topology. This paper exploits the advantages of the Fast Recursive Algorithm, where the number of nodes, the location of centres, and the weights between the hidden layer and the output layer can be identified simultaneously for the radial basis function (RBF) networks. The topology problem for the nonlinear PCA based on neural networks can thus be solved. Another problem with nonlinear PCA is that the derived nonlinear scores may not be statistically independent or follow a simple parametric distribution. This hinders its applications in process monitoring since the simplicity of applying predetermined probability distribution functions is lost. This paper proposes the use of a support vector data description and shows that transforming the nonlinear principal components into a feature space allows a simple statistical inference. Results from both simulated and industrial data confirm the efficacy of the proposed method for solving nonlinear principal component problems, compared with linear PCA and kernel PCA.

ACS Style

Xueqin Liu; Kang Li; Marion McAfee; George W. Irwin. Improved nonlinear PCA for process monitoring using support vector data description. Journal of Process Control 2011, 21, 1306 -1317.

AMA Style

Xueqin Liu, Kang Li, Marion McAfee, George W. Irwin. Improved nonlinear PCA for process monitoring using support vector data description. Journal of Process Control. 2011; 21 (9):1306-1317.

Chicago/Turabian Style

Xueqin Liu; Kang Li; Marion McAfee; George W. Irwin. 2011. "Improved nonlinear PCA for process monitoring using support vector data description." Journal of Process Control 21, no. 9: 1306-1317.

Journal article
Published: 31 August 2011 in Control Engineering Practice
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In polymer extrusion, delivery of a melt which is homogenous in composition and temperature is important for good product quality. However, the process is inherently prone to temperature fluctuations which are difficult to monitor and control via single point based conventional thermocouples. In this work, the die melt temperature profile was monitored by a thermocouple mesh and the data obtained was used to generate a model to predict the die melt temperature profile. A novel nonlinear model was then proposed which was demonstrated to be in good agreement with training and unseen data. Furthermore, the proposed model was used to select optimum process settings to achieve the desired average melt temperature across the die while improving the temperature homogeneity. The simulation results indicate a reduction in melt temperature variations of up to 60%.

ACS Style

Chamil Abeykoon; Kang Li; Marion McAfee; Peter J. Martin; Qun Niu; Adrian Kelly; Jing Deng. A new model based approach for the prediction and optimisation of thermal homogeneity in single screw extrusion. Control Engineering Practice 2011, 19, 862 -874.

AMA Style

Chamil Abeykoon, Kang Li, Marion McAfee, Peter J. Martin, Qun Niu, Adrian Kelly, Jing Deng. A new model based approach for the prediction and optimisation of thermal homogeneity in single screw extrusion. Control Engineering Practice. 2011; 19 (8):862-874.

Chicago/Turabian Style

Chamil Abeykoon; Kang Li; Marion McAfee; Peter J. Martin; Qun Niu; Adrian Kelly; Jing Deng. 2011. "A new model based approach for the prediction and optimisation of thermal homogeneity in single screw extrusion." Control Engineering Practice 19, no. 8: 862-874.

Review
Published: 25 April 2011 in Polymer Engineering & Science
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Rotational molding suffers from a relatively long cycle time, which hampers more widespread growth of the process. During each cycle, both the polymer and mold must be heated from room temperature to above polymer melting temperature and subsequently cooled to room temperature. The cooling time in this process is relatively long due to the poor thermal conductivity of plastics. Although rapid external cooling is possible, internal cooling rates are the major limitation. This causes the process to be uneconomical for large production runs of small parts. Various researchers have strived to minimize cycle times by applying various internal cooling procedures. This article presents a review of these methods, including computer simulations and practical investigations published to date. The effects of cooling rate on the morphology, shrinkage, warpage, and impact properties of rotationally molded polyolefins are also highlighted. In general, rapid and symmetrical cooling across the mold results in smaller spherulite size, increased mechanical properties and less potential warpage or distortion in moldings. POLYM. ENG. SCI., 2011. ©2011 Society of Plastics Engineers.

ACS Style

S.B. Tan; P.R. Hornsby; M.B. McAfee; M.P. Kearns; M.P. McCourt. Internal cooling in rotational molding-A review. Polymer Engineering & Science 2011, 51, 1683 -1692.

AMA Style

S.B. Tan, P.R. Hornsby, M.B. McAfee, M.P. Kearns, M.P. McCourt. Internal cooling in rotational molding-A review. Polymer Engineering & Science. 2011; 51 (9):1683-1692.

Chicago/Turabian Style

S.B. Tan; P.R. Hornsby; M.B. McAfee; M.P. Kearns; M.P. McCourt. 2011. "Internal cooling in rotational molding-A review." Polymer Engineering & Science 51, no. 9: 1683-1692.

Journal article
Published: 29 March 2011 in Neural Computing and Applications
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This paper describes the application of an improved nonlinear principal component analysis (PCA) to the detection of faults in polymer extrusion processes. Since the processes are complex in nature and nonlinear relationships exist between the recorded variables, an improved nonlinear PCA, which incorporates the radial basis function (RBF) networks and principal curves, is proposed. This algorithm comprises two stages. The first stage involves the use of the serial principal curve to obtain the nonlinear scores and approximated data. The second stage is to construct two RBF networks using a fast recursive algorithm to solve the topology problem in traditional nonlinear PCA. The benefits of this improvement are demonstrated in the practical application to a polymer extrusion process.

ACS Style

Xueqin Liu; Kang Li; Marion McAfee; Jing Deng. Application of nonlinear PCA for fault detection in polymer extrusion processes. Neural Computing and Applications 2011, 21, 1141 -1148.

AMA Style

Xueqin Liu, Kang Li, Marion McAfee, Jing Deng. Application of nonlinear PCA for fault detection in polymer extrusion processes. Neural Computing and Applications. 2011; 21 (6):1141-1148.

Chicago/Turabian Style

Xueqin Liu; Kang Li; Marion McAfee; Jing Deng. 2011. "Application of nonlinear PCA for fault detection in polymer extrusion processes." Neural Computing and Applications 21, no. 6: 1141-1148.

Article
Published: 17 March 2011 in Macromolecular Symposia
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Summary: A novel methodology has been developed to describe the microstructure of polymer‐clay nanocomposites quantitatively. It builds on the image analyses of transmission electron microscopy and optical microscopy micrographs, and two parameters, degree of dispersion and mean interparticle distance per unit volume of clay, are proposed to characterize the level of clay dispersion. It provides insights into the ‘real’ clay dispersion using a combination of both microscopical and macroscopical aspects.

ACS Style

Shaobo Xie; Eileen Harkin‐Jones; Yucai Shen; Janet Hill; Peter Hornsby; Marion McAfee; Tony McNally; Raj Patel; Hadj Benkreira; Phil Coates. Quantitative Characterization of Clay Dispersion in Polymer-Clay Nanocomposites. Macromolecular Symposia 2011, 301, 151 -156.

AMA Style

Shaobo Xie, Eileen Harkin‐Jones, Yucai Shen, Janet Hill, Peter Hornsby, Marion McAfee, Tony McNally, Raj Patel, Hadj Benkreira, Phil Coates. Quantitative Characterization of Clay Dispersion in Polymer-Clay Nanocomposites. Macromolecular Symposia. 2011; 301 (1):151-156.

Chicago/Turabian Style

Shaobo Xie; Eileen Harkin‐Jones; Yucai Shen; Janet Hill; Peter Hornsby; Marion McAfee; Tony McNally; Raj Patel; Hadj Benkreira; Phil Coates. 2011. "Quantitative Characterization of Clay Dispersion in Polymer-Clay Nanocomposites." Macromolecular Symposia 301, no. 1: 151-156.

Conference paper
Published: 01 January 2011 in IFAC Proceedings Volumes
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ACS Style

Chamil Abeykoon; Kang Li; Marion McAfee; Peter J. Martin; George W. Irwin. Extruder Melt Temperature Control With Fuzzy Logic. IFAC Proceedings Volumes 2011, 44, 8577 -8582.

AMA Style

Chamil Abeykoon, Kang Li, Marion McAfee, Peter J. Martin, George W. Irwin. Extruder Melt Temperature Control With Fuzzy Logic. IFAC Proceedings Volumes. 2011; 44 (1):8577-8582.

Chicago/Turabian Style

Chamil Abeykoon; Kang Li; Marion McAfee; Peter J. Martin; George W. Irwin. 2011. "Extruder Melt Temperature Control With Fuzzy Logic." IFAC Proceedings Volumes 44, no. 1: 8577-8582.

Conference paper
Published: 01 December 2010 in 49th IEEE Conference on Decision and Control (CDC)
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Laboratory capillary rheometer and side-stream rheometer for melt viscosity measurement in polymer extrusion have shown to be unsuitable for real-time monitoring and control, due to their measurement delay. Existing in-line rheometer designs disturb the melt flow or restrict throughput, limiting their industrial application. In this paper, a novel soft-sensor approach is proposed, aiming to tackle this problem. The soft-sensor involves a non-linear finite impulse response model with adaptable linear parameters for real-time prediction of the melt viscosity based on the process inputs; the model output is then used as an input of a model with a simple fixed structure to predict the barrel pressure which can be measured online. Finally, the predicted pressure is compared to the measured value and the corresponding error is used as a feedback signal to correct the viscosity estimate. This novel feedback structure enables the online adaptability of the viscosity model in response to modeling errors and disturbances, hence producing a reliable viscosity estimate. The experimental results confirm the effectiveness of the proposed `soft-sensor' method for real-time monitoring and control of polymer extrusion processes.

ACS Style

Xueqin Liu; Kang Li; Marion McAfee; Jing Deng. Soft-sensor for real-time monitoring of melt viscosity in polymer extrusion process. 49th IEEE Conference on Decision and Control (CDC) 2010, 3469 -3474.

AMA Style

Xueqin Liu, Kang Li, Marion McAfee, Jing Deng. Soft-sensor for real-time monitoring of melt viscosity in polymer extrusion process. 49th IEEE Conference on Decision and Control (CDC). 2010; ():3469-3474.

Chicago/Turabian Style

Xueqin Liu; Kang Li; Marion McAfee; Jing Deng. 2010. "Soft-sensor for real-time monitoring of melt viscosity in polymer extrusion process." 49th IEEE Conference on Decision and Control (CDC) , no. : 3469-3474.

Journal article
Published: 15 September 2010 in Composites Science and Technology
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Semi-solid forming processes such as thermoforming and injection blow moulding are used to make much of today’s packaging. As for most packaging there is a drive to reduce product weight and improve properties such as barrier performance. Polymer nanocomposites offer the possibility of increased modulus (and hence potential product light weighting) as well as improved barrier properties and are the subject of much research attention. In this particular study, polypropylene–clay nanocomposite sheets produced via biaxial deformation are investigated and the structure of the nanocomposites is quantitatively determined in order to gain a better understanding of the influence of the composite structure on mechanical properties. Compression moulded sheets of polypropylene and polypropylene/Cloisite 15A nanocomposite (5 wt.%) were biaxially stretched to different stretching ratios, and then the structure of the nanocomposite was examined using XRD and TEM techniques. Different stretching ratios produced different degrees of exfoliation and orientation of the clay tactoids. The sheet properties were then investigated using DSC, DMTA, and tensile tests .It was found that regardless of the degree of exfoliation or orientation, the addition of clay has no effect on percentage crystallinity or melting temperature, but it has an effect on the crystallization temperature and on the crystal size distribution. DMTA and tensile tests show that both the degree of exfoliation and the degree of orientation positively correlate with the dynamic mechanical properties and the tensile properties of the sheet.

ACS Style

Rund Abu-Zurayk; Eileen Harkin-Jones; Tony McNally; Gary Menary; Peter Martin; Cecil Armstrong; Marion McAfee. Structure–property relationships in biaxially deformed polypropylene nanocomposites. Composites Science and Technology 2010, 70, 1353 -1359.

AMA Style

Rund Abu-Zurayk, Eileen Harkin-Jones, Tony McNally, Gary Menary, Peter Martin, Cecil Armstrong, Marion McAfee. Structure–property relationships in biaxially deformed polypropylene nanocomposites. Composites Science and Technology. 2010; 70 (9):1353-1359.

Chicago/Turabian Style

Rund Abu-Zurayk; Eileen Harkin-Jones; Tony McNally; Gary Menary; Peter Martin; Cecil Armstrong; Marion McAfee. 2010. "Structure–property relationships in biaxially deformed polypropylene nanocomposites." Composites Science and Technology 70, no. 9: 1353-1359.

Evaluation study
Published: 16 March 2010 in Journal of Materials Science: Materials in Electronics
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Biphasic calcium phosphate (BCP) discs were fabricated and then sintered using two different sintering programs to establish whether the phases present could be controlled at low and high sintering temperatures. X-ray diffraction (XRD) was used to establish the phases present after sintering and scanning electron microscopy (SEM) determined the microstructure. Sintering program 1 involved a simple heating and cooling schedule and temperatures of 1100, 1250, 1275 and 1300°C. It produced samples containing an additional alpha-tricalcium phosphate (α-TCP) phase at temperatures above 1100°C. The original ratio of hydroxyapatite/beta-tricalcium phosphate (HA/β-TCP) could not be maintained above this temperature. Sintering program 2 combined the heating and cooling schedules of the first program with a 900°C hold stage to allow α-TCP to β-TCP conversion to take place. At temperatures of 1250 and 1275°C, this program was successful in completely removing the α-TCP phase and preserving the HA:β-TCP ratio. The SEM results show that the surface morphology of the discs was not greatly affected by choice of sintering program.

ACS Style

O. Brown; Marion McAfee; S. Clarke; F. Buchanan. Sintering of biphasic calcium phosphates. Journal of Materials Science: Materials in Electronics 2010, 21, 2271 -2279.

AMA Style

O. Brown, Marion McAfee, S. Clarke, F. Buchanan. Sintering of biphasic calcium phosphates. Journal of Materials Science: Materials in Electronics. 2010; 21 (8):2271-2279.

Chicago/Turabian Style

O. Brown; Marion McAfee; S. Clarke; F. Buchanan. 2010. "Sintering of biphasic calcium phosphates." Journal of Materials Science: Materials in Electronics 21, no. 8: 2271-2279.