The Experts below are selected from a list of 216 Experts worldwide ranked by ideXlab platform
Mutlu Özcan - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of polymerization shrinkage of bulk-fill resin composites using microcomputed tomography
Clinical Oral Investigations, 2019Co-Authors: Kadriye Aybüke Ersen, Özge Gürbüz, Mutlu ÖzcanAbstract:ObjectivesThis study evaluated the influence of cavity depth on polymerization shrinkage of bulk-fill resin composites with and without adhesive resin.Materials and methodsStandardized box-shaped cavities (width, 4 mm; length, 5 mm, depth, 2 mm or 4 mm) were made on occlusal surfaces of extracted human third molars ( N = 60). The teeth were assigned to 3 groups to receive bulk-fill resin composites (low-viscosity bulk-fill, SDR; high-viscosity bulk-fill; Filtek Bulk-Fill—FB; and TetricEvo Ceram Bulk-Fill—TB) in the prepared cavities with and without adhesive resin (Clearfil S3 Bond). Each specimen ( n = 5 per group) was scanned twice using microcomputed tomography (micro-CT): once after application of the resin composite to the cavity prior to Polymerisation and once after Polymerisation. The shrinkage of volumetric loss (%) was measured using micro-CT. Data were analysed using Kruskal-Wallis and Mann-Whitney U tests (alpha = 0.05).ResultsThe material type ( p
C. Kiparissides - One of the best experts on this subject based on the ideXlab platform.
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Prediction of polymer quality in batch Polymerisation reactors using neural networks
Proceedings of the 1997 American Control Conference (Cat. No.97CH36041), 1997Co-Authors: J. Zhang, E.b. Martin, A.j. Morris, C. KiparissidesAbstract:Neural networks are used to learn the relationship between batch recipes and the trajectories of polymer quality variables in batch Polymerisation. Given a batch recipe, the trained neural networks can predict polymer quality variables during the course of Polymerisation. A main factor affecting prediction accuracy is reactive impurities which commonly exist in industrial Polymerisation reactors. The amount of reactive impurities can be estimated online during the initial stage of Polymerisation using another neural network. Accurate predictions of polymer quality variables can then be obtained from the effective batch initial conditions. The technique can be used to design optimal batch recipes and to monitor Polymerisation processes.
Kadriye Aybüke Ersen - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of polymerization shrinkage of bulk-fill resin composites using microcomputed tomography
Clinical Oral Investigations, 2019Co-Authors: Kadriye Aybüke Ersen, Özge Gürbüz, Mutlu ÖzcanAbstract:ObjectivesThis study evaluated the influence of cavity depth on polymerization shrinkage of bulk-fill resin composites with and without adhesive resin.Materials and methodsStandardized box-shaped cavities (width, 4 mm; length, 5 mm, depth, 2 mm or 4 mm) were made on occlusal surfaces of extracted human third molars ( N = 60). The teeth were assigned to 3 groups to receive bulk-fill resin composites (low-viscosity bulk-fill, SDR; high-viscosity bulk-fill; Filtek Bulk-Fill—FB; and TetricEvo Ceram Bulk-Fill—TB) in the prepared cavities with and without adhesive resin (Clearfil S3 Bond). Each specimen ( n = 5 per group) was scanned twice using microcomputed tomography (micro-CT): once after application of the resin composite to the cavity prior to Polymerisation and once after Polymerisation. The shrinkage of volumetric loss (%) was measured using micro-CT. Data were analysed using Kruskal-Wallis and Mann-Whitney U tests (alpha = 0.05).ResultsThe material type ( p
L M Sergeyeva - One of the best experts on this subject based on the ideXlab platform.
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Porous molecularly imprinted polymer membranes and polymeric particles.
Analytica chimica acta, 2007Co-Authors: L.a. Goncharova, L M SergeyevaAbstract:Porous free-standing molecularly imprinted polymer membranes were synthesised by the method of in situ Polymerisation using the principle of synthesis of interpenetrating polymer networks and tested in solid-phase extraction of triazine herbicides from aqueous solutions. Atrazine-specific MIP membranes were obtained by the UV-initiated co-Polymerisation of methacrylic acid, tri(ethylene glycol) dimethacrylate, and oligourethane acrylate in the presence of a template (atrazine). Addition of oligourethane acrylate provided formation of the highly cross-linked MIP in a form of a free-standing 60 microm thick flexible membrane. High water fluxes through the MIP membranes were achieved due to addition of linear polymers (polyethylene glycol M(w) 20,000 and polyurethane M(w) 40,000) to the initial mixture of monomers before the polymerization. As a result, typical semi-interpenetrating polymer networks (semi-IPNs) have been formed, where the cross-linked polymer was represented by the atrazine-specific molecularly imprinted polymer, while the linear one was represented by polyethylene glycol/polyurethane. Extraction of the linear polymers from the fully formed semi-IPNs resulted in formation of large pores in the membrane structure. At the same time, extraction of the template molecules lead to formation of the sites in the polymeric network, which in shape and arrangement of functional groups are complementary to atrazine. Reference polymeric membranes were prepared from the same mixture of monomers but in the absence of the template. Recognition properties of the MIP membranes were estimated in solid-phase extraction by their ability to selective re-adsorbtion of atrazine from 10(-8) to 10(-4) M aqueous solutions. The imprinting effect was demonstrated for both types of the MIP membranes and the influence of the type of the linear compound on their recognition properties was estimated. The recognition properties of the MIP membranes were compared to those of the MIP particles of the same composition. Morphology of the MIP membranes was investigated using the SEM microscopy. High fluxes of the developed membranes together with high affinity and adsorption capability make them an attractive alternative to MIP particles in separation processes.
Jean-louis Gustin - One of the best experts on this subject based on the ideXlab platform.
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Understanding vinyl acetate polymerization accidents
Chemical Health and Safety, 2005Co-Authors: Jean-louis GustinAbstract:Vinyl acetate is processed to produce polymers and copolymers used in water based paints, adhesives, paper coatings or non-woven binders and various applications at moderate temperatures. The polymerization processes used include solution, suspension and emulsion processes. Many incidents involving the runaway polymerization of vinyl acetate monomers (VAM) are known. In processes where the polymerization initiator was dissolved in the monomer, the initiator premix polymerized violently in the premix vessel. In polymerization processes where vinyl acetate monomer conversion ratio was not 100%, storages of recycled monomers containing no polymerization inhibitor and possibly some traces of polymerization initiator exploded due to VAM violent bulk polymerization. Incidents happened either in batch or semi-batch polymerization processes in connection with wrong initiator introduction. In this paper, a review of polymerization incidents is given. Radical chain polymerization kinetics are used to explain some accident features such as polymerization isothermal induction periods. Experimental results on bulk VAM polymerization are given.
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Understanding Vinyl Acetate Polymerization Accidents
Organic Process Research & Development, 2005Co-Authors: Jean-louis Gustin, Franck LaganierAbstract:Vinyl acetate is processed to produce polymers and copolymers used in water based paints, adhesives, paper coatings or nonwoven binders and various applications at moderate temperatures. The polymerization processes used include solution, suspension and emulsion processes. Many incidents involving the runaway polymerization of vinyl acetate monomers (VAM) are known. In processes where the polymerization initiator was dissolved in the monomer, the initiator premix polymerized violently in the premix vessel. In polymerization processes where vinyl acetate monomer conversion ratio was not 100%, storages of recycled monomers containing no polymerization inhibitor and possibly some traces of polymerization initiator exploded due to VAM violent bulk polymerization. Incidents happened either in batch or semi-batch polymerization processes in connection with wrong catalyst introduction. In this paper, a review of polymerization incidents is given. Radical chain polymerization kinetics are used to explain some acc...
