Dissertations / Theses on the topic 'Screw extruder'
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1
Djuric, Dejan. "Continuous granulation with a twin-screw Extruder." Göttingen Cuvillier, 2008. http://d-nb.info/989861163/04.
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Kulshreshtha, Manoj Kumar. "Modelling and control of a twin screw food extruder." Thesis, University of Reading, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302937.
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Kalali, Kiana. "Quantitative parameters to evaluate mixing in a single screw extruder." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=103764.
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Mixing is crucial in most polymer processing operations towards obtaining high-quality products (e.g. tubing, tire treads and wire coverings). Material type, screw design, and processing conditions all affect mixing profoundly. Different types of mixing elements have been developed to improve mixing in the single screw extruder; however, the selection of these mixing elements is not trivial. In this work, our purpose is to provide quantitative tools to select the best mixing element. Residence time distribution (RTD) and image analysis were used to compare mixing in three different mixing elements: single flight, Maddox, and Saxton. Residence time distributions were used to indirectly grasp an insight about the strain distribution inside the extruder. Experimental RTD data were derived from silica tracer studies and compared to various mixer models. A model based on a plug flow mixer in series with two continuous stirred tanks best fit the experimental data in all three different mixing elements. For the image analysis method the degree of mixing was determined. Mixtures of polyethylene resins with carbon black were extruded and sliced. Subsequently, sliced samples were scanned to provide images showing the distribution of the carbon black in the resin. The RTD experiments showed that the mean residence time is highest in the Saxton mixer and the lowest in the single flight element. Also, the RTD was broadest in the Saxton mixer and narrowest in the single flight mixer. This means that the polymer in the Saxton mixer experiences the widest range of strains and gets mixed more thoroughly. These results were confirmed by image analysis, which showed that polymers mixed in the Saxton mixer were more homogenously mixed compared to the two other mixing elements.Les phénomènes de mélange dans les extrudeuses monovis ont été étudiés en détail depuis de nombreuses années. Le défi principal est le choix des éléments de mélange les mieux appropriés pour une tâche de mélange donnée. A ce jour, les fabricants d'équipements de mise en oeuvre des matières plastiques s'appuient fortement sur des données expérimentales et leur expérience pour opérer ce choix. Dans ce travail, notre objectif est de développer des critères d'évaluation quantitatifs pour différents éléments de mélange dans les extrudeuses monovis. A cet effet, nous comparons l'effat de mélange dans trois éléments de mélange différents (à savoir une zone de vis à filet simple, une zone de mélange à filet barrière de type Maddock, et une troisième zone à picots de type Saxton) en utilisant la distribution du temps de séjour et l'analyse d'images. Pour la distribution du temps de séjour, une matière de traçage est injectée dans la machine, et sa concentration dans l'extrudat déterminée par la pesée du résidu solide des échantillons. Pour l'évaluation optique du mélange, des images de copeaux d'échantillons étaient analysées au moyen d'un logiciel Matlab. Donc, les différents éléments de mélange sont caractérisés, pour les matières utilisées dans cettte étude (des polyoléfines), par la distribution du temps de séjour et la qualité de mélange obtenue par analyse d'image. Mis ensemble, nos résultats confirment que la qualité de mélange obtenue est directement liée à la distribution du temps de séjour; le meilleur résultat est obtenu avec le mélangeur de type Saxton. Les deux paramètres peuvent être utilisés non seulement pour l'évaluation, mais aussi la prédiction de l'effet de mélange dans d'autres conditions et configurations.
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Bravo, Victor. "Finite element simulation of flow in twin screw extruder mixing elements." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0005/NQ42727.pdf.
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Van, Niekerk Werner. "Development of a multi-purpose twin-screw extruder / Werner van Niekerk." Thesis, North-West University, 2009. http://hdl.handle.net/10394/5088.
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Rodriguez, Veloz Oscar Alberto. "The development of laminar morphology in a co-rotating twin screw extruder." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0026/MQ50656.pdf.
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Knott, Brian. "Effective control of a low-cost twin-screw food extruder / Brian Knott." Thesis, North-West University, 2006. http://hdl.handle.net/10394/1640.
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Singh, D. P. "Flow and mixing studies in a co-rotating intermeshing twin screw extruder." Thesis, Brunel University, 1988. http://bura.brunel.ac.uk/handle/2438/5548.
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The basic understanding of mixing in the process of polymer melt extrusion by twin screw extruder is limited by their geometrical complexity and the interactions of the process parameters. Mixing and flow in a 100mm diameter, trapezoidal channeled, intermeshing co-rotating twin-screw extruder have been characterised by determination of residence time distribution (RTD) and of the paths taken by tracers added to the melt. The axial mixing and the effects of varius parameters on it were established by studying RTD using tracer techniques. As the tail of the distribution is of paramount importance, the reproducibility of the RTD curve was extensively studied. Radioactive NnO2 was used as a tracer and detected by gamma ray spectroscopy giving more reproducible results than added barytes estimated gravimetrically after ashing. Shock cooling of the extruder and sectioning of the solidified compound in the screw channels was used to-study the flow mechanism. The maximum throughput achieved, polymer melting mechanism, filled volume and axial mixing Are interrelated, and are dependent on the configuration and position of segmented mixing discs present in the screw profile. In the upstream position these act as melting discs and their efficiency is increased in a closed configuration. Initial melting is achieved over a remarkably short distance along the screw profile. The screw speed affects the axial mixing which is shown to be related to the net relative pressure change at the screw tips. A flow model is proposed such that the overall material flow taking place in an anticlockwise direction along the screw channel comprises two separate flow regimes. The upper regime rotates anti-clockwise and is made up of main and small tetrahedron flow and calender flow. The lower flow regime rotates clockwise and is made up of main and small side leakage flows and a portion of the main tetrahedron flows together with a central flow. The flow studies show conclusively that the melt from a particular site ahead of the intermeshing zone occupies a predestined site after passing through the intermeshing zone.
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Chen, Dong. "An on-line measurement of residence time distribution in a twin-screw extruder /." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61235.
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The importance of the residence time distribution (RTD) in polymer extrusion has been recognized for along time, however, it is very difficult to measure. In this project, an optical on-line RTD measurement technique based on extrudate transmittance changes was investigated. A He-Ne laser beam was the light source, and carbon black was the tracer and detection was performed by a photomultiplier.The RTD of a ZSK-30 twin-screw extruder was measured with and without an in-line rheometer installed. Various operating conditions were used to examine their effects on the RTD curve. It was found that the mean residence time of the system decreased linearly with screw speed and exponentially with the feed rate. The temperature effect was minuscule. The in-line rheometer increased the mean residence time of the system by 80%.
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Mastio, Michael Joseph Becker Bryan R. "Material wear and failure mode analysis of breakfast cereal extruder and screw elements." Diss., UMK access, 2005.
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Thesis (Ph. D.)--School of Computing and Engineering and Dept. of Mathematics. University of Missouri--Kansas City, 2005."A dissertation in engineering and mathematics." Advisor: Bryan R. Becker. Typescript. Vita. Title from "catalog record" of the print edition Description based on contents viewed June 26, 2006. Includes bibliographical references (leaves 133-134). Online version of the print edition.
11
Khan, Maazullah. "Modeling of extrusion cooking of full-fat soybean in a single screw extruder /." free to MU campus, to others for purchase, 1996. http://wwwlib.umi.com/cr/mo/fullcit?p9821347.
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Moysey, Paul A. Thompson Michael Richard. "Discrete element simulation of the solids conveying zone of a single-screw extruder." *McMaster only, 2007.
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Bruce, David P. "Flow field analysis of some mixing and conveying screw element regions, within a closely intermeshing, co-rotating twin-screw extruder." Thesis, Aston University, 1997. http://publications.aston.ac.uk/9602/.
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Grafting of antioxidants and other modifiers onto polymers by reactive extrusion, has been performed successfully by the Polymer Processing and Performance Group at Aston University. Traditionally the optimum conditions for the grafting process have been established within a Brabender internal mixer. Transfer of this batch process to a continuous processor, such as an extruder, has, typically, been empirical. To have more confidence in the success of direct transfer of the process requires knowledge of, and comparison between, residence times, mixing intensities, shear rates and flow regimes in the internal mixer and in the continuous processor. The continuous processor chosen for the current work in the closely intermeshing, co-rotating twin-screw extruder (CICo-TSE). CICo-TSEs contain screw elements that convey material with a self-wiping action and are widely used for polymer compounding and blending. Of the different mixing modules contained within the CICo-TSE, the trilobal elements, which impose intensive mixing, and the mixing discs, which impose extensive mixing, are of importance when establishing the intensity of mixing. In this thesis, the flow patterns within the various regions of the single-flighted conveying screw elements and within both the trilobal element and mixing disc zones of a Betol BTS40 CICo-TSE, have been modelled using the computational fluid dynamics package Polyflow. A major obstacle encountered when solving the flow problem within all of these sets of elements, arises from both the complex geometry and the time-dependent flow boundaries as the elements rotate about their fixed axes. Simulation of the time dependent boundaries was overcome by selecting a number of sequential 2D and 3D geometries, used to represent partial mixing cycles. The flow fields were simulated using the ideal rheological properties of polypropylene and characterised in terms of velocity vectors, shear stresses generated and a parameter known as the mixing efficiency.
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Ban, Kyunha. "Mechanism and Significance of Slip and New Mixing Elements During Flow in Modular Intermeshing Co-Rotating Twin Screw Extruders." University of Akron / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=akron1218132059.
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Ess, J. W. "Characterization of dispersive and distributive mixing in a co-rotating twin-screw compounding extruder." Thesis, Brunel University, 1989. http://bura.brunel.ac.uk/handle/2438/5239.
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A new design of closely intermeshing co-rotating twin-screw compounding extruder, developed at Brunel University, has been utilized in the development of quantitative techniques for characterization of dispersive and distributive mixing in thermoplastics materials prepared by extrusion compounding. Image analysis procedures were used to quantify mixing of polypropylene composites containing calcium carbonate filler using reflected light microscopy on polished surfaces, and transmitted light microscopy of microtomed pigmented sections. Stereological statistics have been applied to raw sample data; results are discussed in relation to mechanistic phenomena influencing particle agglomeration, dispersion and distribution of fillers in thermoplastics. Dispersive or intensive mixing determined from calcium carbonate filled polypropylene specimens showed that processing parameters had no significant influence except when filler was added midway along the machine although the melting zone was highlighted as having a marked effect on the rate of filler dispersion. Premixing of filler and polymer introduced additional agglomeration into the filler. A series of model experiments were undertaken to assess the influence of specific parameters. In this context moisture content emerged as having the single most important effect on filler compaction. Distributive or extensive mixing of carbon black pigmented specimens was very significantly affected by the presence of segmented disc elements at the end of the screws. These elements produced more than a six-fold increase in distributive mixing in the extrudate.
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Stasiek, Andrzej. "Badania procesu współbieżnego dwuślimakowego wytłaczania modyfikowanego polipropylenu przy zmiennej geometrii ślimaków." Rozprawa doktorska, Uniwersytet Technologiczno-Przyrodniczy w Bydgoszczy, 2015. http://dlibra.utp.edu.pl/Content/886.
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Celem pracy było badanie i opis wybranych cech konstrukcyjnych ślimaków wytłaczarki dwuślimakowej współbieżnej oraz parametrów technologicznych procesu na właściwości kompozytów PP/talk wytworzonych w tym procesie
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Oosthuizen, Jan Stephanus. "Development of a twin screw extruder with an integrated cooling roller system / Jan Stephanus Oosthuizen." Thesis, North-West University, 2011. http://hdl.handle.net/10394/8070.
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The Center for Advanced Manufacturing at the Potchefstroom campus of the North West
University aims to develop a twin screw extruder that is able to process powder coating resin.
The facility has thus far produced various components and sub systems for local and
international manufacturers of extrusion products.
The research presented in this thesis aims to both develop a twin screw extruder with an
integrated cooling roller system and to investigate of the performance of a twin screw extruder.
The development of a twin screw extruder consists of the selection of the drive section of the
extruder, the complete design of a twin screw extruder gearbox, the investigation and design of
a suitable barrel for the manufacturing of powder coatings as well as the development of a
unique cooling roller unit for the forming of the processed product when exiting the extruder.
The extruder was manufactured from the designed components and systems. It was found on
further testing that it was capable of producing a powder coating resin of good quality.
In order to evaluate the performance of an extruder, the transfer of energy through the extruder
needs to be understood. Furthermore it is necessary to understand the theory behind each type
of energy being consumed by the extruder, as well as the factors influencing the usage of that
energy.
The theories investigated were verified in practice by measuring the energy consumption of a
twin screw extruder operated under various conditions. These tests provided a correlation
between the consumption of mechanical and electrical energy. The results gave an indication of
the effectiveness of the screw configuration of the processing section of the extruder, making it
possible to determine how the configuration should be amended in order to improve the
performance of the extruder.
The two aims of the thesis were satisfactory completed. The developed twin screw extruder is
able to manufacture powder coatings of good quality and the performance evaluation of a twin
screw extruder was also successfully completed. It enables the manufacturer to measure and
evaluate the energy consumption of the process in order to improve the performance of the
extruder.Thesis (MIng (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2012.
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Elsey, Justin Rae. "Dynamic Modelling, Measurement and Control of Co-rotating Twin-Screw Extruders." University of Sydney. Department of Chemical Engineering, 2003. http://hdl.handle.net/2123/687.
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Co-rotating twin-screw extruders are unique and versatile machines that are used widely in the plastics and food processing industries. Due to the large number of operating variables and design parameters available for manipulation and the complex interactions between them, it cannot be claimed that these extruders are currently being optimally utilised. The most significant improvement to the field of twin-screw extrusion would be through the provision of a generally applicable dynamic process model that is both computationally inexpensive and accurate. This would enable product design, process optimisation and process controller design to be performed cheaply and more thoroughly on a computer than can currently be achieved through experimental trials. This thesis is divided into three parts: dynamic modelling, measurement and control. The first part outlines the development of a dynamic model of the extrusion process which satisfies the above mentioned criteria. The dynamic model predicts quasi-3D spatial profiles of the degree of fill, pressure, temperature, specific mechanical energy input and concentrations of inert and reacting species in the extruder. The individual material transport models which constitute the dynamic model are examined closely for their accuracy and computational efficiency by comparing candidate models amongst themselves and against full 3D finite volume flow models. Several new modelling approaches are proposed in the course of this investigation. The dynamic model achieves a high degree of simplicity and flexibility by assuming a slight compressibility in the process material, allowing the pressure to be calculated directly from the degree of over-fill in each model element using an equation of state. Comparison of the model predictions with dynamic temperature, pressure and residence time distribution data from an extrusion cooking process indicates a good predictive capability. The model can perform dynamic step-change calculations for typical screw configurations in approximately 30 seconds on a 600 MHz Pentium 3 personal computer. The second part of this thesis relates to the measurement of product quality attributes of extruded materials. A digital image processing technique for measuring the bubble size distribution in extruded foams from cross sectional images is presented. It is recognised that this is an important product quality attribute, though difficult to measure accurately with existing techniques. The present technique is demonstrated on several different products. A simulation study of the formation mechanism of polymer foams is also performed. The measurement of product quality attributes such as bulk density and hardness in a manner suitable for automatic control is also addressed. This is achieved through the development of an acoustic sensor for inferring product attributes using the sounds emanating from the product as it leaves the extruder. This method is found to have good prediction ability on unseen data. The third and final part of this thesis relates to the automatic control of product quality attributes using multivariable model predictive controllers based on both direct and indirect control strategies. In the given case study, indirect control strategies, which seek to regulate the product quality attributes through the control of secondary process indicators such as temperature and pressure, are found to cause greater deviations in product quality than taking no corrective control action at all. Conversely, direct control strategies are shown to give tight control over the product quality attributes, provided that appropriate product quality sensors or inferential estimation techniques are available.
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Jordaan, Corrie. "The development of a control system for gravimetric feeding of a twin screw extruder / Jordaan C." Thesis, North-West University, 2012. http://hdl.handle.net/10394/8183.
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The control of gravimetric feeding is generally done by control systems which utilize
feedback control. The main problem with these control systems is that they generally revert
to volumetric feeding during the refilling cycle. Furthermore the control system software is
proprietary information and therefore not in the public sector and also very expensive. The
main purpose of the study was therefore to review the basics of gravimetric feeding and to
apply the knowledge in the design of a control system with applicable software for
gravimetric feeding which is not affected by material bulk density variations, targeting food
extrusion applications. It is also aimed at producing a test bench to test the control system
and the developed software.
The developed control system is a programmable logic controller (PLC) based control
system. This allows for the control system to be easily integrated into any PLC controlled
twin screw extruder. The control system was extensively tested to verify the developed
gravimetric control algorithms. The results from the experimental tests illustrated that a fully
functional gravimetric feeding system had been developed. Most importantly also that the
volumetric characteristics of a material can be used, to assist a PI–controlled gravimetric
feeding system in both the feeding cycle and the refilling cycle.Thesis (MIng (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2012.
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Liang, Tian. "Continuous Devulcanization of Ground Tire Rubber of Different Particle Sizes Using an Ultrasonic Twin-Screw Extruder." University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1366063285.
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Hojabr, Sassan. "Mathematical modeling and process investigation of melt grafting reactions in an intermeshing co-rotating twin screw extruder." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0004/NQ27829.pdf.
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Michalska-Pożoga, Iwona. "Influence of the disc mechanism plasticization in screw - disk extruder on mechanical proprieties material : PhD thesis summary." Rozprawa doktorska, [s.n.], 2006. http://dlibra.tu.koszalin.pl/Content/1201.
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Bumm, Sug Hun. "Mixing Studies and Simulation of Compounding Chopped Fiber and Silica Filler into Thermoplastics in a Modular Co-Rotating Twin Screw Extruder." University of Akron / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=akron1271956146.
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Кумар, Джаяш. "Лінія для виробництва труб з модернізацією екструдера." Bachelor's thesis, КПІ ім. Ігоря Сікорського, 2020. https://ela.kpi.ua/handle/123456789/34559.
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Робота складається з вступу і трьох розділів. Загальний обсяг роботи 85 аркушів основного тексту та 3 додатків.
Метою роботи є чер’вяка для виробництва труб з ПВХ. Спроектована лінія дозволить випускати труби з ПВХ, які мають значний ряд переваг в порівнянні з трубами з чавуну і сталі.
У даній роботі був спроектований черв’ячний прес ЧП-63. Виконані всі необхідні параметричні розрахунки, теплові розрахунки і розрахунки на міцність.The work consists of an introduction and three sections. The total volume of 85pages of main text, 3 applications. The aim is modernization of the screw of the production of polyvinyl chloride pipes. Designed line will allow to produce polyvinyl chloride pipes, which have a significant number of advantages compared with the pipes of iron and steel. The screw extruder is designed in the paper. Achieved required parametric calculations and strength calculations. Results of diploma project have been considered at chair СPSE seminar
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Imhoff, Andreas. "Dreidimensionale Beschreibung der Vorgänge in einem Einschneckenplastifizierextruder = Three-dimensional description of the process in a single screw plasticating extruder /." Aachen : Mainz, 2004. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=013369621&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
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Gatt, Etienne. "Etude de la déconstruction de résidus agricoles lignocellulosiques par extrusion biocatalytique." Thesis, Toulouse, INPT, 2019. http://www.theses.fr/2019INPT0006/document.
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L’extrusion biocatalytique, ou bioextrusion, est une technique d’extrusion réactive utilisant des enzymes comme catalyseurs. Cette technique est considérée en temps qu’étape intermédiaire, subséquente au prétraitement physico-chimique et précédente à l’hydrolyse enzymatique enréacteur fermé. L’utilisation de l’extrusion permet un procédé continu, facilement modulable et adaptable à des conditions de hautes consistances, de nombreuses biomasses et facilement transférable à l’échelle industrielle. Néanmoins, les données bibliographiques font ressortir la complexité des entrants et leurs interactions lors de la bioextrusion de biomasses lignocellulosiques. Les conclusions des bioextrusions de biomasses amidonnées soulignent l’importance de l’étude de l’influence de la concentration en substrat et en enzymes. Les résultats obtenus à partir de la bioextrusion des biomasses lignocellulosiques valident l’existence d’une activité enzymatique en extrudeuse malgré la contrainte thermomécanique et le temps de séjour limité. Lors de cette étape, l’hydrolyse de la fraction cellulosique est favorisée pour des milieux concentrés en substrat et en enzymes. Des modifications significatives des fractions cellulosiques cristallines et amorphes en surface, des réductions des tailles de particules, une dégradation visuelle des structures de la biomasse et l’augmentation de la sensibilité à la décomposition thermique, sont aussi observées sur la fraction solide. L’hydrolyse enzymatique des bioextrudats est prolongée en réacteur fermé. La bioextrusion permet des améliorations significatives des taux et vitesses de conversion des sucres sur le long terme, jusqu’à 48 h. Les gains observés sont relativement constants pour la paille de blé et augmentent avec le temps pour les écorces de bouleau et les résidus de maïs. Post-extrusion, la concentration en substrat influence négativement la conversion des sucres. Cependant, les plus-values de conversion du glucose lié à la bioextrusion de paille de blé sont principalement observables pour des concentrations en substrat et en enzymes élevées. À partir de 4 h, des baisses significatives de la conversion du xylose sont observées après bioextrusion. Les déstructurations de la fraction solide, déjà observées au cours la bioextrusion, se poursuivent en réacteur fermé. Les meilleurs résultats hydrolytiques aux niveaux des hautes charges en enzymes et en substrat sont associables aux bonnes conditions de mélanges caractéristiques des éléments bilobes. L’ensemble enzymatique est probablement réparti de façon plus homogène (mélange distributif) pour cibler plus de sites disponibles. De plus, le mélangé dispersif limite la proximité entre enzymes de même type et les gênes associées. Le procédé d’extrusion permet une agitation efficace, un bon transfert de masse et probablement un meilleur contact entre enzymes et substrat. Les moins bons résultats de conversion du xylose sont probablement à relier à des phénomènes d’adsorption non-spécifique, ou encore de désactivation des hémicellulases, provoqués par l’intensité des contraintes thermomécaniques et les résidus ligneux. Les bons résultats de déstructuration après bioextrusionsont associables à une action synergétique des contraintes mécanique et biochimique. Les analyses d’autofluorescence montrent l’évolution de la fraction ligneuse dans le processus de déconstruction de la fraction solide. Une production progressive de particules très fines,visiblement associée à la fraction ligneuse, est observée. Des complexes lignine-carbohydratessont aussi détectés dans la fraction liquide. Etant peu, voire pas hydrolysable par voie enzymatique, ces fractions hétéropolymériques sont un frein à la déconstruction. Si la déstructuration des lignines est probablement majoritairement liée au prétraitement alcalin, le procédé de bioextrusion provoque une diminution de la teneur en hétéropolymères de plus hautes masses moléculairesBiocatalytic extrusion, also named bioextrusion, is a reactive extrusion technique using enzymes as catalysts. Bioextrusion is considered as a link between the previous physico-chemical pretreatment (like alkaline extrusion) and the subsequent enzymatic hydrolysis in batch conditions. The extrusion allows a continuous, flexible and versatile process for high consistency media, easily transferable to the industrial level. However, complexity of both lignocellulosic biomass and lignocellulolytic enzymes and their interactions during the extrusion process are underlined by the literature. Numerous response surface methodology experiments with starchy biomass indicate that bioextrusion efficiency is mainly influenced by substrate and enzymes loading. Enzymatic activity during the bioextrusion process of lignocellulosic biomass is confirmed by the experiments despite the mechanical constraints and the limited residence time. During bioextrusion, best holocellulosic fraction hydrolysis results were obtained with high substrate and enzymes loadings. Significant modifications of the solid fraction like particule size reduction, visual deconstruction of the biomass structure, increased sensibility to thermal decomposition and the evolution of the surface exposure of crystalline and amorphous cellulose were observed. Enzymatic hydrolysis of the bioextrdates is prolonged in batch conditions. Clear improvements of speeds and rates of sugars conversion up to 48 h indicate a long term influence of the bioextrusion. Gain observed are steady for the pretreated wheat straw whereas it increases with time for corn residues and birch barks. Post-extrusion, a negative influence of the substrate loading is measured. However, best enhancements for the glucose conversion of pretreated wheat straw are detected for high substrate and enzymes loadings. From 4 to 48 h, significant losses in xylose conversion are measured with previous bioextrusion. Indicators of the solid fraction deconstruction, observed during the bioextrusion step, indicate a stronger biomass degradation after 48 h. Improvements of glucose conversion rates can be associated with good mixing conditions of the extruder, especially due to the use of kneading elements. Enzymes are probably more homogeneously distributed (distributive mixing) and can access more catalytic sites available. Moreover, dispersive mixing limits the enzyme jamming due to the biocatalysts concentration. Extrusion process permits an better agitation efficiency, good mass transfer conditions and probably a higher contact between substrate and enzymes. Lower xylose conversion results may be attributed to non-specific adsorptions or inactivation phenomena due to mechanical constraints and lignin residues. Good deconstruction results on the solid fraction may be associable with a synergetic action between mechanical and biochemical constraints. Autofluorescent signal analysis of the lignin fraction show its evolution during the deconstruction of the solid residue. During the hydrolysis, a progressive production of very small particles, appearing to be associated with the lignin fraction is observed. Lignin-carbohydrate complexes are also detected in the liquid fraction. These heteropolymeric complexes, difficult or even impossible for the enzymes to hydrolyze, are an obstacle to the biomass valorization. If lignin deconstruction is mainly due to the alkaline pretreatment, bioextrusion process seems to reduce the proportion of these heteropylymers with high molecular weights
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Vera-Sorroche, Javier. "Thermal homogeneity and energy efficiency in single screw extrusion of polymers : the use of in-process metrology to quantify the effects of process conditions, polymer rheology, screw geometry and extruder scale on melt temperature and specific energy consumption." Thesis, University of Bradford, 2014. http://hdl.handle.net/10454/13965.
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Polymer extrusion is an energy intensive process whereby the simultaneous action of viscous shear and thermal conduction are used to convert solid polymer to a melt which can be formed into a shape. To optimise efficiency, a homogeneous melt is required with minimum consumption of process energy. In this work, in-process monitoring techniques have been used to characterise the thermal dynamics of the single screw extrusion process with real-time quantification of energy consumption. Thermocouple grid sensors were used to measure radial melt temperatures across the melt flow at the entrance to the extruder die. Moreover, an infrared sensor flush mounted at the end of the extruder barrel was used to measure non-invasive melt temperature profiles across the width of the screw channel in the metering section of the extruder screw. Both techniques were found to provide useful information concerning the thermal dynamics of the extrusion process; in particular this application of infrared thermometry could prove useful for industrial extrusion process monitoring applications. Extruder screw geometry and extrusion variables should ideally be tailored to suit the properties of individual polymers but in practise this is rarely achieved due the lack of understanding. Here, LDPE, LLDPE, three grades of HDPE, PS, PP and PET were extruded using three geometries of extruder screws at several set temperatures and screw rotation speeds. Extrusion data showed that polymer rheology had a significant effect on the thermal efficiency on the extrusion process. In particular, melt viscosity was found to have a significant effect on specific energy consumption and thermal homogeneity of the melt. Extruder screw geometry, set extrusion temperature and screw rotation speed were also found to have a direct effect on energy consumption and melt consistency. Single flighted extruder screws exhibited poorer temperature homogeneity and larger fluctuations than a barrier flighted screw with a spiral mixer. These results highlighted the importance of careful selection of processing conditions and extruder screw geometry on melt homogeneity and process efficiency. Extruder scale was found to have a significant influence on thermal characteristics due to changes in surface area of the screw, barrel and heaters which consequently affect the effectiveness of the melting process and extrusion process energy demand. In this thesis, the thermal and energy characteristics of two single screw extruders were compared to examine the effect of extruder scale and processing conditions on measured melt temperature and energy consumption. Extrusion thermal dynamics were shown to be highly dependent upon extruder scale whilst specific energy consumption compared more favourably, enabling prediction of a process window from lab to industrial scale within which energy efficiency can be optimised. Overall, this detailed experimental study has helped to improve understanding of the single screw extrusion process, in terms of thermal stability and energy consumption. It is hoped that the findings will allow those working in this field to make more informed decisions regarding set conditions, screw geometry and extruder scale, in order to improve the efficiency of the extrusion process.
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Heel, Annika Kristin [Verfasser]. "Solvent-Free Processes for the Formation of β-Cyclodextrin Inclusion Complexes Within a Melt-Twin-Screw-Extruder / Annika Kristin Heel." Kiel : Universitätsbibliothek Kiel, 2018. http://d-nb.info/1156602025/34.
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Faye, Mamadou. "Nouveau procédé de fractionnement de la graine de Neem (Azadirachta Indica A. Jussi) sénégalais : production d'un bio-pesticide d'huile et de tourteau." Thesis, Toulouse, INPT, 2010. http://www.theses.fr/2010INPT0070/document.
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Originaire de l'Inde, le neem (Azadirachta indica Juss.) est un arbre présent dans les zones tropicales sèches et subtropicales d'Asie, d'Amérique et d'Afrique. Au Sénégal, il produit en moyenne 50 kg par an d'un fruit sous forme de drupe ellipsoïdale, qui contient en général une graine, d'un poids moyen de 270 ± 30 à 91 % de matière sèche. La variabilité des caractéristiques des graines (45 à 48 % de coques fibreuses : cellulose 52 à 54 %, hémicelluloses 24 à 28 %, lignine 7 à 9 % ; 52 à 55 % d'amandes : lipides 45 à 58 %, protéines 20 à 23 %j) et des huiles extraites (acides palmitiques : 17 à 19 %, stéarique : 14,5 à 17,5 %, oléique : 42 à 48,5 %, linoléique : 16,5 à 20 % ; stérols totaux : 3 à 5 g/kg) est analysée pour 5 régions du Sénégal. L'extraction de l'azadirachtine, principal principe actif phytosanitaire de la graine, par différents solvants (méthanol, éthanol, eau) révèle une teneur de 2 g par kg de graine, localisée essentiellement dans l'amande (3,9 g/kg). Les conditions d'expression de l'huile de graine de neem sont étudiées en presse mono-vis OMEGA 20 et en extrudeur bi-vis CLEXTRAL BC 21. Dans les meilleures conditions, 65 et 68 % de l'huile sont exprimées, 7 à 10 % de l'azadirachtine sont entraînées avec l'huile, et le tourteau contient 14 % de lipides, 14 % de protéines et près de 2 g/kg d'azadirachtine. Le fractionnement acqueux, sous cisaillement intense des graines, conduit à l'extraction de 55 % des lipides, 50 % des protéines et 80 % de l'azadirachtine, séparés sous forme d'une émulsion stable, de composition : eau 70 %, huile 25 %, protéines 4 %, azadirachtine 6 g/kg, et d'une phase aqueuse. L'étude de la mise en œuvre du procédé d'extraction et de séparation, en extrudeur bi-vis CLEXTRAL BC 21 puis BC 45, permet de produire en continu 0,3 kg d'émulsion stable par kg de graine traitée (20 kg/h) avec un ratio eau/graine de 2 et une température de 60°C. Le tourteau ne contient plus que 0,6 g/kg d'azadirachtine, et l'émulsion stable qui en contient 5 g/kg peut être directement mise en œuvre dans les formulations d'insecticide totalement biosourcésOriginally from India, neem (Azadirachta indica Juss.) is a tree found in the dry tropics and subtropics of Asia, America and Africa. In Senegal, it produces an average of 50 kg per year of a fruit as a drupe ellipsoid, which generally contains a seed, with an average weight of 270 ± 30 to 91% dry matter. The variability of seeds (45 to 48% of capsular cellulose 52-54%, 24-28% hemicellulose, lignin 7-9% 52-55% almonds: 45 to 58% lipids, proteins 20 to 23% j) and extracted oils (palmitic acid: 17 to 19%, stearic: 14.5 to 17.5%, oleic acid: 42 to 48.5%, linoleic: 16.5 to 20% total sterols: 3 5 g / kg) was analyzed for five regions of Senegal. Extraction of azadirachtin, the main active ingredient of the plant seed by different solvents (methanol, ethanol, water) shows a content of 2 g per kg of seed, mainly localized in the kernel (3.9 g / kg ). The expression conditions of neem seed oil were studied in single-screw press OMEGA 20 and twin-screw CLEXTRAL BC 21. Under optimum conditions, 65 and 68% of the oil is expressed, from 7 to 10% of azadirachtin are entrained with the oil and meal contains 14% fat, 14% protein and about 2 g / kg azadirachtin. Watery splitting under intense shear seeds, led to the extraction of 55% lipids, 50% protein and 80% of azadirachtin, separated as a stable emulsion, composition: water 70% oil 25%, 4% protein, 6 g azadirachtin / kg, and an aqueous phase. The study of the implementation of the method of extraction and separation, twin-screw extruder and then CLEXTRAL BC 21 BC 45, produces continuous stable emulsion 0.3 kg per kg of treated seed (20 kg / h) with a ratio water / seed of 2 and a temperature of 60 ° C. The cake contains only 0.6 g / kg of azadirachtin, and stable emulsion which contains 5 g / kg can be directly implemented in the formulations of insecticide biosourced completely
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Mondadori, Nilcéa Mares da Luz. "Processamento de compósitos de poli (tereftalato de etileno) reciclado reforçado com fibras de vidro." reponame:Repositório Institucional da UCS, 2007. https://repositorio.ucs.br/handle/11338/237.
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Neste trabalho, compósitos de PET sob a forma de flake e pós-condensado foram preparados com teores diferenciados de fibra de vidro (0, 20, 30 e 40%). Dois tipos de fibra foram utilizados: uma fibra com tratamento superficial a base de amino-silano e outra com tratamento a base de epóxi-silano. Os compósitos foram extrusados em extrusora mono-rosca, utilizando uma rosca de filete duplo com barreira, e em extrusora dupla-rosca interpenetrante co-rotacional. Após extrusão, os compósitos foram injetados a 120 ºC que, após várias temperaturas testadas, foi a temperatura que conferiu maior grau de cristalinidade do artefato final (acima de 30%). Os compósitos foram caracterizados quanto às propriedades mecânicas, térmicas e morfológicas. Os resultados mostraram que com a utilização de uma mono-rosca apropriada ao processamento de PET com fibra de vidro foi possível produzir compósitos com boas propriedades, comparáveis aos obtidos em extrusora dupla-rosca. Em relação aos tipos de PET utilizados, verificou-se que a massa molar da matriz polimérica, maior para o PET pós-condensado, teve uma pequena influência no desempenho das propriedades analisadas. Porém foi observado que os resultados foram indiferentes ao tratamento superficial das fibras testadas. Através da determinação do comprimento das fibras por análise óptica, e dos resultados experimentais do módulo de tração dos compósitos, pode-se constatar que nos compósitos injetados as fibras estão orientadas no sentido longitudinal à deformação. Com a microscopia eletrônica de varredura verificou-se que há sempre uma melhor distribuição e dispersão das fibras, com menores vazios à medida que aumenta o teor de fibras, corroborando os resultados mecânicos, sempre crescentes com o teor incorporado. A cristalinidade obtida nos corpos de prova moldados por injeção com o molde a uma temperatura de 120 ºC, aliada à presença da fibra de vidro, leva a um aumento na temperatura de distorção térmica (HDT). As análises de raios-X mostraram que com o aumento da quantidade da fibra, os picos cristalinos característicos do PET perdem definição, o que está associado à característica amorfa da fibra.Submitted by Marcelo Teixeira (mvteixeira@ucs.br) on 2014-05-15T17:17:43Z No. of bitstreams: 1 Dissertacao Nilcea Mondadori.pdf: 5475607 bytes, checksum: 3b5580025f75099d47502055cd80fde5 (MD5)
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In this work, flake and post-condensed PET composites of different glass fiber contents (0, 20, 30 and 40%) were prepared. Tow kinds of fibers were employed: one fiber having an amino silane-based surface treatment and another one having an epoxi silane-based surface treatment. The composites were extruded in a single-screw extruder with a barrier double-flight screw, and in a co-rotating interpenetrating twin-screw extruder. After extrusion the composites were injected at 120°C, this temperature being chosen after several tests indicating that it could promote the highest possible degree of crystallinity of the final product (higher than 30%). The composites were characterized as for mechanical, thermal and morphological features. Data indicate that by using a single-screw extruder proper to the processing of PET and fiber glass the properties of the obtained composites are fairly good, being comparable to those obtained from a twin-screw extruder. As for the types of PET utilized, it could be found that the molar mass of the polymeric matrix, larger for the post-condensed PET had some influence on the performance of the tested properties. On the other hand it could be observed that the surface treatment of the fibers does not influence the obtained data. Based on the optical analysis of the fiber length and the elastic modulus data it is possible to determine that the fibers of the injected composites are oriented longitudinally to the strain direction. With the aid of scanning electron microscopy (SEM), improvements in the distribution and dispersion of the fibers were always observed, with smaller voids as the fiber content increases, backing higher mechanical data as the incorporated fiber content is increased. Crystallinity resulting from injection-molded test specimens processed at 120°C, together with the presence of the glass fiber leads to a synergism in the heat distortion temperature (HDT). X-rays analyses indicate that at higher fiber content the composites show lower definition of the crystalline peaks, this being associated to the amorphous feature of the fiber.
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Gnana, Mani Joseph Wilfred [Verfasser], H. [Akademischer Betreuer] Altenbach, H. J. [Akademischer Betreuer] Radusch, and R. H. [Akademischer Betreuer] Schuster. "Continuous mixing of silica based rubber, filler-composites in twin screw extruder / Joseph Wilfred Gnana Mani. Betreuer: H. Altenbach ; H.-J. Radusch ; R. H. Schuster." Halle, Saale : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2010. http://d-nb.info/1024976033/34.
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Agrawal, Akash. "Examining the Effectiveness of Different Mixing Elements in the Twin Screw Compounding of Liquid Crystal Polymer and Polypropylene." Case Western Reserve University School of Graduate Studies / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=case1512742062745962.
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Butterfield, Craig. "A novel laboratory dispersive and distributive minimixer and applications : development of a new minimixer that can duplicate mixing which occurs in a large twin screw extruder." Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/4930.
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The mixing of additives into a plastic is an extremely important step in the plastics industry, necessary for the manufacture of almost every conceivable product. Therefore the costs in developing new products can prove very expensive as the testing is usually carried out using full scale machines, usually using twin screw extruders because they are able to provide good dispersive and distributive mixing. This is particularly important when compounding difficult to disperse additives and nano-additives. What is required is a machine that can replicate the mixing abilities of a twin-screw extruder but on a laboratory scale. There have been attempts by industry to develop smaller machines, such as the Thermo Scientific HAAKE Minilab II Micro Compounder which processes on the scale of 7 cm3 of material volume. This can be too small for some needs and therefore a machine is required to produce material on the 10g to 100g scale. To this end a laboratory mixer of novel design was devised and its mixing performance was assessed using conductive carbon black and compared against the Thermo Scientific HAAKE Minilab II Micro Compounder, a 19 mm co-rotating twin-screw extruder and a 40 mm co-rotating twin-screw extruder. Carbon black was used because mixing performance can be assessed by measuring the minimum carbon loading necessary to induce electrical conductivity. It was found that the minimixer was able to induce electrical conductivity at loading of 5.75% but the comparison with the other machines proved difficult as the achievement of the threshold at which semi-conductivity occurred appeared independent of shear rate and mixing duration.
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Bryson, Latoya G. "Monomer recovery from nylon carpets via reactive extrusion." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22618.
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Thesis (Ph. D.)--Chemical and Biomolecular Engineering, Georgia Institute of Technology, 2008.Committee Chair: Muzzy, John D.; Committee Member: Cook, Fred L.; Committee Member: Jones, Christopher W.; Committee Member: Mayor, J. Rhett; Committee Member: Realff, Matthew J.; Committee Member: Schork, F. Joseph.
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Barbosa, Rafael. "Desenvolvimento de novos compostos de borracha natural a partir da desvulcanização em extrusora com rosca dupla." Universidade Federal de São Carlos, 2017. https://repositorio.ufscar.br/handle/ufscar/9057.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
The present study investigated the utilization efficiency of an intermeshing co-rotating twin-screw extruder (ICTSE) in the devulcanization of natural rubber compounds (NR), evaluating the physical, chemical and mechanical characteristics of these materials in each project step. Three accelerated compounds with different sulfur concentrations were submitted to torque rheometry and vulcanized according these results aiming the achievement of elastomers with different crosslinks densities. The influences on the characteristics of the devulcanized material caused by the variation of the extruder barrel temperature, screw rotation, thermoplastics addition and material stiffness were evaluated. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), infrared spectroscopy (FTIR), soluble fraction extraction and crosslink density were performed, evaluating the devulcanized compound. Horikx's theory was also used as an indicator of selective crosslink cleavage, defining the compounds to be revulcanized for comparison with the virgin pure material. The revulcanization was carried out with the mixture of the devulcanized compound with the pure, in the proportions of 30/70 w/w, respectively, and in the devulcanized compound singularly, with addition of complementary vulcanization system in both cases. The mechanical, dynamic-mechanical and crosslink density properties of the revulcanized compounds were characterized and evaluated in relation to the properties of the pure compounds. The increase in the concentration of uncrosslinked BN chains and the concentration of sulfur compounds in the extruded samples was observed by thermal tests and spectrocopy, together with the verification of a high level of devulcanization percentage, according to Flory-Rehner, evidencing the regeneration of the natural rubber existent. Also, satisfactory mechanical properties were found in the revulcanized compounds, especially when using auxiliary thermoplastics, revealing the great potential of ERDCI processing for the reuse of discarded BN compounds.
O presente estudo avaliou a eficiência de utilização de uma extrusora com rosca dupla co-rotacional e interpenetrante (ERDCI) na desvulcanização de compostos de borracha natural (BN), avaliando as características físicas, químicas e mecânicas destes materiais em cada fase do projeto. Três compostos acelerados com diferentes concentrações de enxofre foram submetidos a reometria de torque, e vulcanizados de acordo com a curva reométrica, para obtenção de elastômeros com diferentes densidades de ligações cruzadas. Foram avaliadas as influências nas características do material desvulcanizado, causadas pela variação da temperatura do barril da extrusora, velocidade de rotação das roscas, adição de termoplásticos e módulo elástico do material. Análises de termogravimetria (TGA), calorimetria exploratória diferencial (DSC), espectroscopia no infravermelho (FTIR), fração solúvel (FS) e densidade de ligações cruzadas foram realizadas, avaliandose o composto desvulcanizado. A teoria de Horikx também foi utilizada como indicativa da seletividade de ruptura de ligações cruzadas, definindo os compostos a serem revulcanizados para comparação com o material virgem. A revulcanização foi realizada com a mistura de 30 %(m/m) do composto desvulcanizado e 70 %(m/m) do puro, e também com 100 % do composto desvulcanizado, e adição de sistema de vulcanização complementar. Caracterizou-se os compostos revulcanizados quanto às suas propriedades mecânicas, dinâmico-mecânicas e densidade de ligações cruzadas. Através dos ensaios TGA, DSC, FTIR e a verificação de alto nível de percentual de desvulcanização pela teoria de Flory- Rehner, foi observado o aumento da concentração de cadeias de BN não reticuladas e da concentração de compostos de enxofre nas amostras extrudadas, evidenciando a regeneração da BN presente nos compostos. Também foram encontradas propriedades mecânicas satisfatórias nos compostos revulcanizados, principalmente quando utilizados termoplásticos auxiliares, revelando o grande potencial do processamento por ERDCI para a reutilização de compostos de BN descartados.
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Zhang, Xian-Ming. "Simulation par CFD et mesure en ligne de la distribution des temps de séjour et la qualité de mélange dans une extrudeuse bi-vis." Thesis, Vandoeuvre-les-Nancy, INPL, 2008. http://www.theses.fr/2008INPL066N/document.
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Aujourd’hui le développement de nouveaux matériaux polymères ayant de bonnes propriétés repose de plus en plus sur des procédés de mélange ou de compoundage de polymères au lieu de recourir à la synthèse de nouvelles molécules. L’action du mélange peut fortement influer sur la morphologie des matériaux polymères multi-constituants. Les extrudeuses bi-vis (TSE) sont souvent utilisées comme mélangeurs/réacteurs pour des procédés de mélange, de compoundage et d’extrusion réactive. Cependant, l’étude sur la qualité du mélange dans les TSE demeure un grand défi en raison de la complexité géométrique et du caractère transitoire de l’écoulement. Cette thèse a pour objet de développer un nouvel instrument en line pour mesurer en temps réel la distribution des temps de séjour (DTS) qui caractérise la performance du mélange axial et la capacité de convoyage de différents types d’éléments de vis basées sur l’analyse de l’écoulement transitoire et l’évaluation systématique de la théorie de mélange dans les TSE. Le mélange distributif des polymères fondus est caractérisé par la génération de l’aire des interfaces, un paramètre difficile à mesurer expérimentalement. Alors on fait appel à des simulations numériques de type CFDThe development of new materials with improved properties seems to rely nowadays more on blending and compounding than on the synthesis of chemically new polymers. Mixing may have a great effect on the morphology and structure of multi-component polymer materials. Twin-screw extruders (TSE) are widely used as mixers/reactors for blending, compounding, and reactive processing. This work aimed at developing a new instrument to measure in real time the residence time distribution (RTD) which characterizes the axial mixing and transport abilities of different screw elements based on the analysis of the transient flow pattern and systematic evaluation of mixing theory in TSE. Distributive mixing of polymer melts is characterized by the generation of interfacial area, which is experimentally much more difficult to measure. This 3D numerical simulation based on CFD is adopted
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Gai, Jing-Gang. "Etudes théoriques et expérimentales de la processabilité du polyéthylène à ultra-haute masse molaire." Thesis, Vandoeuvre-les-Nancy, INPL, 2009. http://www.theses.fr/2009INPL039N/document.
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Aujourd’hui le développement de nouveaux matériaux polymères ayant de bonnes propriétés repose de plus en plus sur des procédés de mélange ou de compoundage de polymères au lieu de recourir à la synthèse de nouvelles molécules. L’action du mélange peut fortement influer sur la morphologie des matériaux polymères multi-constituants. Les extrudeuses bi-vis (TSE) sont souvent utilisées comme mélangeurs/réacteurs pour des procédés de mélange, de compoundage et d’extrusion réactive. Cependant, l’étude sur la qualité du mélange dans les TSE demeure un grand défi en raison de la complexité géométrique et du caractère transitoire de l’écoulement. Cette thèse a pour objet de développer un nouvel instrument en line pour mesurer en temps réel la distribution des temps de séjour (DTS) qui caractérise la performance du mélange axial et la capacité de convoyage de différents types d’éléments de vis basées sur l’analyse de l’écoulement transitoire et l’évaluation systématique de la théorie de mélange dans les TSE. Le mélange distributif des polymères fondus est caractérisé par la génération de l’aire des interfaces, un paramètre difficile à mesurer expérimentalement. Alors on fait appel à des simulations numériques de type CFDThe development of new materials with improved properties seems to rely nowadays more on blending and compounding than on the synthesis of chemically new polymers. Mixing may have a great effect on the morphology and structure of multi-component polymer materials. Twin-screw extruders (TSE) are widely used as mixers/reactors for blending, compounding, and reactive processing. This work aimed at developing a new instrument to measure in real time the residence time distribution (RTD) which characterizes the axial mixing and transport abilities of different screw elements based on the analysis of the transient flow pattern and systematic evaluation of mixing theory in TSE. Distributive mixing of polymer melts is characterized by the generation of interfacial area, which is experimentally much more difficult to measure. This 3D numerical simulation based on CFD is adopted
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Belyamani, Imane. "Développement d'un matériau thermoplastique biodégradable et hydrosoluble à base d'une protéine du lait." Phd thesis, Université Jean Monnet - Saint-Etienne, 2011. http://tel.archives-ouvertes.fr/tel-00702749.
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La biomasse représente l'une des principales alternatives à l'utilisation du pétrole dans la plasturgie. Grâce à leurs propriétés fonctionnelles, les caséinates sont une matière première prometteuse pour la fabrication de films plastiques pour des applications dans l'emballage biodégradable et hydrosoluble. La transformation du caséinate de sodium par les techniques habituellement utilisées dans la plasturgie a été démontrée. Des extrudats de caséinate plastifié au glycérol ont été obtenus au moyen d'une extrudeuse bi-vis corotative. La caractérisation physico-chimique du matériau obtenu a confirmé la thermostabilité de cette protéine et a montré la dépendance du comportement du matériau vis-à-vis de l'humidité ambiante. Pour une variation du taux d'Humidité Relative, de 40 à 90% et une augmentation de la concentration du glycérol, plastifiant hygroscopique, le matériau passe d'un état vitreux (rigide) à un état caoutchouteux (mou). Des films fins ont été ensuite réalisés, à partir des extrudats thermoplastiques, par extrusion gonflage. La perméabilité à la vapeur d'eau des films de caséinate de sodium a été étudiée et a montré que ces matériaux sont de mauvaises barrières à l'humidité. La deuxième partie a été consacré à l'étude de mélanges caséinate de sodium/caséinate de calcium d'un côté et caséinate de sodium/PBAT de l'autre. Le mélange des deux caséinates a permis d'augmenter la tenue mécanique du mélange, à partir de 50% de caséinate de calcium, et de retarder le transfert hydrique à travers le film. Dans le même sens, l'ajout du PBAT, a augmenté jusqu'à deux fois plus, le module d'Young des mélanges mais a baissé la résistance au transfert d'humidité du film à cause de l'incompatibilité des deux polymères.
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Lai-F. "Melt conveying in counter-rotating twin-screw extruders." Thesis, Imperial College London, 1985. http://hdl.handle.net/10044/1/37751.
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Theng, Dyna. "Feasibility of incorporating treated lignin and cellulose nanofiber in fiberboards made from corn stalk and rice straw." Doctoral thesis, Universitat de Girona, 2017. http://hdl.handle.net/10803/461717.
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Agricultural waste is of particularly interest due to abudant, cheap, widely available worldwide and renewable material. It represent a good option for wood sources substitution, containing similar in chemical and physical characteristics. The present Doctoral Thesis studies the possibility of substituting wood sources by crop residues and replacing synthetic binders by natural adhesives in fiberboard production. Corn and rice biomass were selected as raw materials, followed by thermo-mechanical pulping (TMP) pretreatment. Fiberboards made of TMP of both crop residues without any binder presented lower mechanical properties than commercial ones (which contained synthetic binder). In term of physical properties, lower water absorption and thickness swelling were found for the fiberboards made of crop residues than for the commercial one. Overall, the present study shows a more sustainable and effective way of producing cellulose-based fiberboards without aid of any synthetic binder, contributing thus to both technical and environmental aspects of fiberboard manufacturingEls residus agrícoles tenen un gran interès per ser un material abundant , barat, àmpliament disponible a tot el món i renovable. Es tracta d'una bona opció per substituir la fusta, i presenta característiques físiques i químiques similars a aquesta. La present tesi doctoral estudia la possibilitat de substituir la fusta i els aglutinants sintètics per residus de cultius i adhesius naturals respectivament en la producció panell de fibres. La biomassa de blat de moro i arròs sotmesa a un tractament termomecànic (TMP)es va seleccionar com a matèria primera. El panell de fibra resultant d'ambdós residus sense cap tipus d'aglutinant presentaven propietats mecàniques més baixes que els panells comercials (que contenien un lligant sintètic). Respecte a les propietats físiques, es va observar un augment de volum i espessor al absorbir aigua menors en el panell de fibres naturals que no pas en els comercials. En general, el present estudi mostra una forma més sostenible i efectiva de produir panells de fibra a base de cel·lulosa sense utilitzar aglutinant sintètic, fet que contribueix a la millora d’aspectes tècnics i ambientals en el procés de fabricació dels panells de fibra
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Sax, Gerhard Ludwig. "Twin-screw extruded lipid implants for controlled drug delivery." Diss., lmu, 2012. http://nbn-resolving.de/urn:nbn:de:bvb:19-146306.
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Jaffer, Shafiq A. "Experimental studies of static mixers and twin screw extruders." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0006/NQ42854.pdf.
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Jaffer, Shaffiq A. "Experimental studies of static mixers and twin screw extruders /." *McMaster only, 1998.
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Covas, Jose A. C. G. "Processing of UPVC in single and twin screw extruders." Thesis, Loughborough University, 1985. https://dspace.lboro.ac.uk/2134/11942.
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The processing characteristics of PVC compounds play a major role on the ability of the equipment to control the final properties of the product. Therefore, information on the effect of processing conditions on such characteristics. and its influence on the final properties can lead to an optimization of the extrusion process. In this work. a statistically based experimental design was used in order to investigate the role of the operating conditions on the extrusion of a simple lead based PVC formulation. Both a single and a twin screw extruder were used - they were instrumented, and data collected by computer. A die was designed for the formulation used. with both shear and extensional flows being taken into account. These experiments produced both core samples along the screw(s) and final products with varying states of fusion. The fusion mechanism on processing was monitored with the help of electron and light microscopy techniques. thermal analysis and density measurements. In both types of extruders the primary particles were found to fuse well before the grains, but the overall mechanism differs for each type of machine. An experimental technique was developed for the study of the Residence Time (RT) and Residence Time Distribution (RTD) of the material in the processing equipment. These functions were related to the operating conditions and compared with the available models for extrusion. The degree of fusion of the processed products was assessed by rheology and thermal analysis. A range of mechanical properties, relevant to the general end - use of rigid PVC formulations. was analysed: flexural. tensile and impact properties were found to be directly related with fusion level. Hardness, measured using a newly developed apparatus. proved to be a potential technique for the degree of gelation of PVC formulations.
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Lenhard, Allison N. "Review of energy harvesting methods for twin screw extruders." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/127922.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020Cataloged from the official PDF of thesis.
Includes bibliographical references (pages 44-48).
Energy harvesting is the process of accumulating and storing energy from residual sources for use in powering electronic devices. Low-power energy harvesting technologies typically utilize either mechanical, thermal, radiation, flow-based, or bio-chemical energy sources. Research in low-power energy harvesting technologies is motivated by an increased interest in the Internet of Things and the need to create isolated electronic systems, such as wireless sensor networks for system monitoring. Twin screw extruders are a type of extrusion processing machinery and could benefit from a condition monitoring system. Implementing a condition monitoring system for a twin screw extruder can prevent wasting materials, producing unusable products, and working extensively on machine maintenance. However, it becomes difficult to integrate a condition monitoring system into the machinery because of the lack of accessibility. Condition monitoring would have to occur in the process section of the twin screw extruder, but the nature of the process section makes it difficult to implement a traditionally wired and powered condition monitoring system. A condition monitoring system powered by energy harvesting techniques would be ideal for a twin screw extruder. The shaft mechanical vibrations, high temperature thermal dissipation, and polymer fluid dynamics present in a twin screw extruder can potentially be used in an energy harvesting system. After a literature review, mechanical vibrations and temperature gradients were regarded as the best potential energy harvesting drivers. Based on preliminary analysis of the system, vibrational energy harvesting is predicted to produce between 3.35-16.75 mW of power, while thermally driven energy harvesting is expected to produce between 8-15 mW of power. The estimated power output would be significant enough to power a low-power consumption strain sensor and has the potential to power other sensors as well.
by Allison N. Lenhard.
S.B.
S.B. Massachusetts Institute of Technology, Department of Mechanical Engineering
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Schuler, Werner. "Process engineering design of co-rotating twin screw extruders." Thesis, Swansea University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.572814.
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The intention of the work was to develop easy to use technical design methods which are helpful for the daily work of the process engineer, and which also describe the operating behaviour of both the whole extruder and the individual processing sections. This goal was achieved by developing new models or the further developing of existing models. The examination of the developed models by trials and on production lines showed good accuracy of the models. The following models, which are developed in the present work, are of particular interest for the technical design of extruders: • Simple model for the calculation of the solids conveying capacity derived by trials. • Calculation of the melt transport in screw elements by simple models which are examined by test series with various extruder sizes, screw elements and polymers. • Design rules for screw elements used for melt discharge. • A model for the description of the degassing process was derived in terms of the operating equation of the degassing zone. The described operating equation shows a good agreement with degassing results obtained in various degassing trials. • Description of the operating behaviour of solid fed extruders and a simple assessment of the specific drive energy using the specific enthalpy rise. • Introduction of the mean shear stress at the barrel wall for melt fed co-rotating twin screw extruders and description of the operating behaviour by the operating equation. The influence of different feed temperatures and melt flow index values are also considered. • Scale-up for compounding and degassing tasks and the necessary restrictions to achieve the same results on test and production extruders. • Development of an analytical method for the design of extruder series by the optimal diameter ratio, dependent on whether the extruders are melt or solid fed.
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Ji, Wei-Yun. "Développement d'un concept d'agent compatibilisant-traceur réactif visant à étudier l'évolution de la réaction interfaciale et de la morphologie de mélanges de polymères réactifs." Thesis, Université de Lorraine, 2016. http://www.theses.fr/2016LORR0247/document.
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Le mélange de polymères est une méthode répandue pour élaborer des matériaux polymères. Cependant, la plupart des polymères sont thermodynamiquement immiscibles entre eux, engendrant une séparation de phase des mélanges et une détérioration de leurs propriétés. Afin de palier ces problèmes, la méthode dite compatibilisation réactive est souvent employée. Elle est basée sur la formation in-situ de copolymères à bloc ou greffés par l’intermédiaire de réactions interfaciales entre polymères réactifs. Cette thèse a pour objet de développer un concept dit agent compatibilisant-traceur réactif qui permettra d’utiliser de faibles quantités d’agents compatibilisants réactifs pour évaluer leurs efficacités de compatibilisation directement sur des extrudeuses bi-vis industrielles, d’une part ; et de caractériser la performance du mélange d’une extrudeuse bi-vis en fonction des conditions opératoires et/ou du profil de vis employé. Ses principales contributions se résument ci-après. L’anthracène de 9-méthylaminométhyle (MAMA), une molécule fluorescente, est incorporée dans un copolymère statistique de styrène (St) et d’isocyanate de 3-isopropenyle-?, ?’-diméthylebenzène (TMI), noté PS-TMI, pour former un agent compatibilisant-traceur réactif, noté PS-TMI-MAMA. Ce dernier sert à la fois comme agent compatibilisant réactif grâce aux groupements isocyanate et traceur grâce aux groupements fluorescents. Il est utilisé pour les mélanges à base de polystyrène (PS) et de polyamide 6 (PA6) afin d’évaluer son efficacité de compatibilisation. Les mélanges PS/PA6 sont élaborés dans un mélangeur discontinu et une extrudeuse bi-vis, respectivement. Dans le cas du mélangeur discontinu, la quantité du copolymère greffé formé in-situ, noté PS-g-PA6-MAMA, augmente alors que le diamètre des domaines de la phase dispersée (DDD) diminue considérablement au début du mélange. Lorsque le mélange se poursuit, le nombre de greffons en PA6 du PS-g-PA6-MAMA augmente, engendrant une composition très asymétrique du PS-g-PA6-MAMA qui est thermodynamiquement instable aux interfaces. De ce fait, il peut être arraché des interfaces vers la phase PA6 et peut y former des micelles. Lorsqu’il est arraché des interfaces, il perdra son efficacité de compatibilisation et le DDD augmentera. L’action du mélange a un double effet sur le procédé de compatibilisation réactive. Il promeut la réaction interfaciale entre le PS-TMI-MAMA et le PA6, d’une part ; et aggrave l’arrachage du PS-g-PA6-MAMA de l’interface, d’autre part. L’utilisation de faibles quantités de l’agent compatibilisant-traceur réactif permet de mesurer les évolutions de la teneur en agent compatibilisant-traceur réactif, du DDD et de la teneur en agent compatibilisant-traceur réactif ayant réagi en fonction du temps de séjour dans une extrudeuse bi-vis. Pour une masse molaire donnée, l’efficacité de compatibilisation d’un agent compatibilisant-traceur réactif augmente avec l’augmentation de la teneur en TMI dans une certaine limite. Pour une teneur en TMI donnée, la réaction interfaciale est plus rapide avec la diminution de la masse molaire dans une certaine limite et le DDD devient plus petit en un temps plus court. L’influence du taux de remplissage de la vis est plus significative que celle du temps de séjour. Lorsque le taux de remplissage de la vis augmente, le taux de la réaction interfaciale augmente et le DDD diminue. Lorsque l’angle d’un élément de mélange augmente, les efficacités du mélange distributif et du mélange dispersif augmentent, ce qui se traduit par une augmentation de la quantité du PS-g-PA6-MAMA formée et une diminution du DDD par rapport à la même quantité de PS-g-PA6-MAMA produite. Lorsque la largeur d’un élément de mélange augmente, l’efficacité du mélange distributive augmente alors que celle du mélange dispersif demeure inchangée. La substitution d’éléments de mélange par des éléments inverses améliore l’efficacité du mélange distributif et celle du mélange dispersifPolymer blending is a common method to prepare high-performance polymer materials. However, most polymer pairs are thermodynamically immiscible, leading to phase separation and deterioration in material properties. To overcome such problems, the most common method is reactive compatibilization which is based on the in-situ formation of a graft or block copolymer by interfacial reaction between reactive polymers. This thesis aims at developing a concept of reactive compatibilizer-tracer which will allow using small amounts of reactive compatibilizers to evaluate their compatibilizing efficiency in industrial scale twin screw extruders, on the one hand; and to characterize the mixing performance of a twin screw extruder as a function of process conditions and/or screw profile. Its main contributions are summarized below. 9-(methylaminomethyl) anthracene (MAMA), a fluorescent molecule, is incorporated into a random copolymer of styrene (St) and 3-isopropenyl-?, ?’-dimethylbenzene isocyanate (TMI), denoted as PS-TMI, to form a reactive compatibilizer-tracer, denoted as PS- TMI-MAMA. The latter serves both as a reactive compatibilizer due to its isocyanate moieties and a tracer due to its fluorescent moieites. It is used for polystyrene (PS)/polyamide 6 (PA6) blends to evaluate its compatibilizing efficiency. Compatibilized PS/PA6 blends are processed in a batch mixer and in a twin screw extruder, respectively. In the case of the batch mixer, the amount of the in-situ formed graft copolymer denoted as PS-g-PA6-MAMA increases and the dispersed phase domain diameter (DDD) decreases drastically in the initial period of mixing. As the mixing further proceeds, the number of PA6 grafts of the PS-g-PA6-MAMA increases, resulting in a highly asymmetrical composition of the PS-g-PA6-MAMA which causes thermodynamic instablility at the interface. As a result, it could be pulled out of the interface to the PA6 phase and form micelles. Once it is pulled out of the interface, it will lose its compatibilizing efficiency and the dispersed phase domain diameter increases sharply. Mixing has a dual effect on the reactive compatibilization process. On the one hand, it promotes the interfacial reaction between the PS-TMI-MAMA and PA6. On the other hand, it aggravates the pull out of the resulting PS-g-PA6-MAMA from the interface. The use of small amounts of the reactive compatibilizer-tracer together with transient experiments for RTD allows assessing the evolutions of the reactive compatibilizer-tracer content (CC), the dispersed phase domain diameter (DDD), and the reacted reactive compatibilizer-tracer content (RCC) as a function of residence time in a twin-screw extruder. Based on the above results, the emulsification curve (DDD vs. CC), the RCC vs. CC curve and effective emulsification curve (DDD vs. RCC) are obtained. When the molar mass of the reactive compatibilizer-tracer is fixed, its compatibilizing efficiency increases with increasing TMI content within an appropriate range. When its TMI content is fixed, the interfacial reaction goes faster as the molar mass of the reactive compatibilizer-tracer decreases within a certain range, and the DDD becomes smaller in a shorter time. The effect of degree of fill fixed by the throughput Q/screw speed N ratio is more dominant than that of residence time. As the degree of fill increases, the interfacial reaction increases and the DDD decreases. As the angle of adjacent the kneading block increases, its distributive and dispersive mixing efficiencies increase, resulting in an increase in interfacial area generation and a decrease in DDD on the basis of the same amount of PS-g-PA6-MAMA. On the other hand, as the width of the kneading block increases, the distributive mixing efficiency increases and the dispersive mixing efficiency remains unchanged. Substitution of kneading blocks by reverse ones increase both the distributive and dispersive mixing efficiencies
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Nguyen, Quang Hung. "Study on bioaccumulation and integrated biorefinery of vegetable oil and essential oil of Coriander (Coriandrum sativum L.)." Phd thesis, Toulouse, INPT, 2015. http://oatao.univ-toulouse.fr/16038/1/Nguyen_QH.pdf.
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Apiaceae could be defined as Aroma Tincto Oleo Crops (ATOC), e.g. plants containing both vegetable oil and essential oil. Applying agroreffinery concept to ATOC led to propose a sequential fractionation process coupling co-extraction of vegetal oil and essential oil to a valorization of by-product residues as biosourced active molecules and substrates for designing agromaterials. The aim of this thesis is to determine the biological and technological feasability of application of the ATOC-refinery concept to coriander (Coriandrum sativum L.) Chapter I reports a bibliographic state of the art study on extraction and characterisation of coriander vegetal oil and essential oil while chapter II describes materials and methods setting up during the thesis for sampling, extraction, analysis and data processing. Chapter III focus on the study of major various biological parameters influencing bioaccumulation of vegetal oil and essential oil in coriander (different plant varieties, different plant organs, different biological stages) and their impact on anti-oxidant activity of extracts obtained from extraction residues. In chapter IV, coriander fruits are processed by extrusion technology (mono screw and twin-screw extruder) in order to evaluate the feasability of mechanical pressing for extracting a flavored vegetal oil. Influence of operating parameters on vegetal oil extraction yields (nozzle diameter and nozzle/screw distance (single-screw extruder) or screw configuration, device’s filling coefficient and pressing temperature (twin-screw extruder)) is studied while the feasability of valorization of extraction cake as agromaterial (thermopressing) was stated.
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Yu, Dingwen. "Development of an intelligent design tool for polymer screw extruders." Thesis, Nottingham Trent University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324589.
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Wood, A. K. "The lubricating effects of polymer melts in single screw extruders." Thesis, Manchester Metropolitan University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374971.
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