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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
121

Análise in vitro da toxicidade celular de tubos de PVC esterilizados consecutivamente em raios gama e óxido de etileno / Cell toxicity in vitro analysis of PVC tubes consecutively submitted to gamma-rays and ethylene oxide sterilization

Souza, Rafael Queiroz de 28 June 2010 (has links)
Em 1967, uma carta enviada ao British Medical Journal relatou que a re-esterilização em Óxido de Etileno (EO) do Cloreto de Polivinil (PVC) previamente gamairradiado forma grandes quantidades de etileno cloridrina, um composto altamente tóxico. Mesmo não apresentando dados mensurados, esta carta iniciou uma polêmica que até hoje divide a opinião de pesquisadores. Dirimir esta dúvida é relevante, uma vez que produtos de PVC esterilizados em Radiação Gama são habitualmente reesterilizados em EO em caso de vencimento do período de validade da esterilização, que é determinado pelo fabricante. Este estudo objetivou evidenciar a toxicidade de tubos de PVC por meio do teste de citotoxicidade pelo método da difusão em ágar em culturas celulares NCTC clone 929. Foram criados quatro grupos experimentais com 81 unidades de análise: G1, constituído de tubos in natura; G2 constituído de tubos esterilizados em Radiação Gama; G3 constituído de tubos esterilizados em EO e G4 constituído de tubos esterilizados em Raios Gama e re-esterilizados em Óxido de Etileno. Os testes foram realizados em triplicata e cada tubo foi testado de forma a representar as superfícies internas, externas e massa. Após a mensuração do halo incolor, as unidades de análise foram graduadas de acordo com os graus de reatividade biológica descritos na norma ISO 10993-5:2009. Foram consideradas citotóxicas apenas as unidades análise que obtiveram grau três ou acima. Os resultados revelaram toxicidade celular apenas no grupo G3, no qual foram observadas placas com morte de todas as células, fato que demandou repetições, conforme a metodologia adotada. Na primeira repetição houve persistência de unidades de análise capazes de causar a morte de todas as células da placa. Na segunda repetição, nenhuma unidade de análise foi classificada como citotóxica. Inferiu-se que houve falhas no processo de aeração no grupo G3 e na primeira repetição. O resultado da cromatografia gasosa dos grupos G3 e G4 atestou que os materiais de ambos os grupos estariam seguros para uso. O valor máximo dos resíduos encontrados em ambos os grupos foi idêntico, contradizendo os resultados do teste de citotoxicidade. Concluiu-se que, nas condições deste experimento, os materiais de PVC esterilizados em Radiação Gama e, consecutivamente, reesterilizados em EO não são citotóxicos e a cromatografia gasosa, utilizada isoladamente, pode produzir resultados questionáveis quanto à segurança dos materiais esterilizados em EO. / In 1967, a letter sent to the British Medical Journal reported that the re-sterilization with Ethylene Oxide (EtO) of previously irradiated Polyvinyl Chloride (PVC) formed large amounts of ethylene chlorohydrin, a highly toxic compound. Even though it did not present measured data, this letter initiated a controversy that still divide the opinion of researchers to date. To solve this doubt is relevant, as PVC products submitted to gamma radiation are usually re-sterilized with EtO, when the sterilization validity has expired, which is determined by the manufacturer. The present study aimed at assessing the toxicity of PVC tubes through the cytotoxicity test, using the NCTC clone 929 cell culture agar diffusion test. Four experimental groups were created with 81 analysis units: G1, consisting of tubes in natura; G2, consisting of tubes submitted to gamma radiation; G3, consisting of tubes submitted to EtO sterilization and G4, consisting of tubes submitted to gamma-radiation and re-sterilized with EtO. The tests were carried out in triplicate and each tube was tested in order to represent its internal and external surfaces, as well as its mass. After the measurement of the colorless halo, the analysis units were graded according to the degrees of biological reactivity described in the ISO 10993-5:2009. Only the analysis units that were considered grade 3 and above were considered cytotoxic. The results showed evidence of cell toxicity only in G3, which disclosed plaques that presented death of all cells, a fact that necessitated repetition of the experiment, according to the adopted methodology. The first repetition showed the persistence of the analysis units to cause the death of all cells in the plaque. At the second repetition, none of the analysis units was classified as being cytotoxic. It was inferred that there were failures in the process of aeration in group G3 and in the first repetition. The results of the gas chromatography of groups G3 and G4 demonstrated that the materials from both groups would be safe for use. The maximum value of residues found in both groups was identical, in disagreement with the cytotoxicity test results. It was concluded that, according to the conditions of this experiment, the PVC materials submitted to gamma-radiation and consecutively sterilized by EtO are not cytotoxic and that the gas chromatography, when used alone, can yield debatable results regarding the safety of materials sterilized with EtO.
122

Fonologi hos svenska 5- och 6-åringar med typisk språkutveckling : Referensmaterial till det fonologiska testmaterialet LINUS / Phonology in Swedish 5- and 6-year old Children with Typical Language Development : The Results of a Study to Establish a Reference Manual for the Phonological Test Material LINUS

Berglund, Josefin, Hasselquist, Kaisa January 2014 (has links)
A new phonological test, LINUS, for Swedish-speaking children between the ages of three and seven, has been developed at the speech and language pathology department at Linköping University. The aim of the present study was to create a reference manual for the long version of the new test. The participants in the present study were children between the ages of five to seven in a medium-sized municipality in the Northern part of Kalmar County, Sweden. In total, 124 native Swedish-speaking children (58 girls and 66 boys) with typical language development participated. The children were divided into two age groups, 5;0-5;11;31 and 6;0-6;11;31 years. The collected data was analysed with respect to acquisition of phonemes and word structure processes. Percentage of correctly produced words (PWC), consonants (PCC) and vowels (PVC) were calculated.All phonemes, except /s/, were established in both age groups. The phoneme /s/ was found to be either substituted or distorted. Among the 5-year old children /s/ was established for 84%, substitutions of /s/ were found in 7% and distortions were found in 23%. Among the 6-year old children /s/ was established for 88%. Substitutions of /s/ were found in 3% and distortions in 16% of the 6-year old children. The phoneme /r/ proved to be a borderline case for acquisition in the younger age group (91%). The most common word structure process in both groups was assimilation. A significant difference between the two age groups was found for assimilation (p=0,022), with lower occurrence in the older group. Two-consonant clusters (CC) and three-consonant clusters (CCC) were not frequently reduced, although it was found that CC-clusters were reduced more frequently than CCC-clusters. Both the age groups had high percentages of correctly produced words, consonants and vowels. The analysis revealed the following results: PWC for 5-years olds was 93% and 6-years olds 97%. PCC for 5-year olds was 98% and for 6-year olds 99%. PVC for both age groups was 100%. An age difference was shown for PWC, but not for the other measures. No gender differences were found. / Ett nytt fonologiskt testmaterial, LINUS, är framtaget för svensktalande barn. I föreliggande studie har referensmaterial till den långa versionen av det nya testet insamlats bland barn 5-7 år i en mellanstor kommun i norra Kalmar län. Totalt deltog 124 barn (58 flickor och 66 pojkar) med svenska som modersmål och typisk språkutveckling. Barnen delades upp i två åldersintervall, 5;0-5;11;31 och 6;0-6;11;31 år. Det insamlade materialet analyserades avseende etablering av fonem och konsonantkombinationer, samt förekomst av ordstrukturprocesser. Andelsmått för korrekt uttalade ord (PWC), konsonanter (PCC) och vokaler (PVC) beräknades.Samtliga fonem, utom /s/, var etablerade i båda åldersgrupperna. Fonemet /s/ realiserades med substitutioner eller kvalitativt marginella avvikelser (KMA). I 5-årsgruppen var /s/ etablerat för 84% av deltagarna. Bland 5-åringarna förekom substitutioner av /s/ hos 7% och KMA förekom hos 23%. I 6-årsgruppen var /s/ etablerat till 88%, och det förekom substitutioner hos 3% av 6-åringarna, och KMA förekom hos 16%. Fonemet /r/ visade sig vara ett gränsfall avseende etablering för den yngre åldersgruppen (91%). Den vanligaste ordstrukturprocessen för båda grupperna var assimilationer. Signifikanta skillnader mellan de två åldersgrupperna återfanns avseende assimilationer, p=0,022. Förekomsten av assimilationer minskade med stigande ålder. Tvåkonsonantskombinationer (CC) och trekonsonantskombinationer (CCC) visade sig ej vara påverkade av förenklingar i någon större grad. Dock visade sig CC-kombinationer vara mer utsatta för förenklingar än CCC-kombinationer. Båda åldersgrupperna hade höga andelar korrekt uttalade ord, konsonanter och vokaler. De två grupperna fick följande resultat: PWC för 5-åringar var 93% och 6-åringar 97%. PCC var 98% respektive 99% för grupperna. PVC var 100% för båda åldersgrupperna. Åldersskillnader kunde ses för PWC, dock inte för de andra måtten. Inga könsskillnader noterades.
123

Flatstickad distanstextil : Formstickad 3D-struktur och fokus på vidhäftningsförmågan hos olika bindningar.

Ewert, Mia, Ulfsson, Moa January 2018 (has links)
Sjöräddningssällskapet har sedan 1907 räddat liv genom frivilliga sjöräddare. De har en vision om att kunna effektivisera sina räddningsaktioner genom att skicka ut en drönare till olycksplatsen för att få en övergripande bild av händelsen och på så sätt kunna anpassa rätt utrustning och personal. Idén var att konstruera drönarens kropp i form av en textil 3D-struktur, detta skulle underlätta dess användning då den skulle bli flexibel och vid olycksplatsen kunna stuvas undan och förflyttas smidigare. Tanken är att drönaren ska ha en konstruktion som kan blåsas upp och bli styv för att sedan kunna tömmas på luft och bli flexibel. Syftet med denna studie är att ta fram en flatstickad distanstextil som ska fungera som en kropp till en drönare där förhoppningen är att den textila 3D-kroppen ska kunna formstickas som en vinge. I distanstextil skapas luftrum mellan lagren vilket möjliggör att en uppblåsbar konstruktion kan skapas. Genom att variera olika parametrar kan man även ta fram önskade egenskaper som styvhet, form, flexibilitet samt lättvikt. För att skapa en distanstextil som är styv i uppblåst läge krävs en beredning. Trikåvaror är generellt svåra att bereda, därför har studien undersökt olika trikåbindningars förmåga att vidhäfta mot beredningar.   Den formstickade distansstrukturen i väfttrikå tillverkades på en flatstickmaskin, där formen skapades genom masköverhängningar. Genom att binda distanstråden på olika nålavstånd kunde ett ovalt tvärsnitt uppnås. För att undersöka olika bindningars förmåga att vidhäfta mot beredningar testades flatstickade 2D-prover. Bindningarna var slätstickning, pikévariant över 2 system, pikévariant över 4 system samt slätstickning med plätering. De olika beredningar som undersöktes var silikonbeläggning, polyuretanfilm, polyetenfilm tillsammans med polyuretanfilm samt en polypropenfilm. Syftet var att hitta en beredning som är lätt i vikt, luft- och vattentät. Ett vidhäftningstest utfördes på bindningarna slätstickning, pikévariant över 2 system samt pikévariant över 4 system med hjälp av en dragprovare för bestämning av de olika bindningarnas vidhäftning mot olika lamineringar. De tre bindningarna i kombination med laminering testades även för luft- och vattentäthet.   Studien visar att det finns goda möjligheter att formsticka en flatstickad distanstextil som ska fungera som en kropp till en drönare. Resultatet visar att provkroppen som var stickad med pikévariant över två system samt laminerad med polyuretanfilmen gav bäst resultat vid utfört vidhäftningstest. Vid test av luftgenomsläpplighet visade pikévariant över två system med laminering av polyuretanfilm tillsammans med en polyetenfilm tätast resultat med låg luftgenomsläpplighet. Test för bestämning av vattentäthet visar att den slätstickade varan med en laminering med polyetenfilm och en polyuretanfilm gav bäst resultat. / Since 1907, the Swedish Sea Rescue Society has saved lives with the help of volunteer workers. Their vision is to be able to improve their rescue operations with quicker respond times by sending out a drone to the scene of an accident. The idea is to get a comprehensive picture of the scene, so they can adapt the right equipment and personnel for the job. The idea is to create a drone with a textile 3D structure, which would ease use as it would become flexible and easier to remove from the scene of the alarm. The drone should have a structure similar to a stand-up paddle board, where it can be inflatable and become stiff and then be deflated and folded and tucked away.   The purpose of this study is to develop a flat knitted spacer fabric that will serve as a body of the drone, hoping that the textile 3D structure can be shaped like a wing. With spacer fabrics, space for air is created between the layers, enabling an inflatable construction to be created. By varying different parameters, one can also develop desired features such as stiffness, shape, flexibility and decrease weight. To be able to create a spacer fabric that is stiff when inflated, a finishing process is required. It is generally hard to find a finishing to a knitted fabric, therefore the study investigates the ability of different bindings on a knitted fabric to adhere to finishes.   The shaped spacer fabric was manufactured by weft knitting on a flat knitting machine called Stoll CMS 822 HP. A wing shaped spacer and an oval cross section were achieved in this study. To investigate how the binding affects the adhesion of the finishing, three different bindings of flat knitted 2D- structures were tested. The bindings were: plain fabric (single jersey), pique structure over 2 feeders, pique structure over 4 feeders and plain fabric with plating. The finishing processes that were studied were silicone coating, a polyurethane film, a polyethylene film and a polypropylene film. The aim was to find a finishing with the properties of light weight, air and water tightness. An adhesion test was performed on the bindings plain fabric, pique structure over 2 feeders and pique structure over 4 feeders by a tensile tester to determine the adhesion between the tested bindings and finishes. These test specimens were also tested to determine resistance to water penetration and air permeability.   The study shows that it is possible to create a shaped spacer fabric by flat knitting, that will act as the body of a drone. The result of the adhesion test shows that the test specimen with binding pique over 2 feeders and laminated with a polyurethane film performed the best. In the air permeability test the same binding showed the best result but with a lamination of a polyurethane film and a polyethylene film. The test to determine resistance to water penetration showed that the binding plain fabric was the best, with a lamination of a polyurethane film, and a polyethylene film.
124

Análise in vitro da toxicidade celular de tubos de PVC esterilizados consecutivamente em raios gama e óxido de etileno / Cell toxicity in vitro analysis of PVC tubes consecutively submitted to gamma-rays and ethylene oxide sterilization

Rafael Queiroz de Souza 28 June 2010 (has links)
Em 1967, uma carta enviada ao British Medical Journal relatou que a re-esterilização em Óxido de Etileno (EO) do Cloreto de Polivinil (PVC) previamente gamairradiado forma grandes quantidades de etileno cloridrina, um composto altamente tóxico. Mesmo não apresentando dados mensurados, esta carta iniciou uma polêmica que até hoje divide a opinião de pesquisadores. Dirimir esta dúvida é relevante, uma vez que produtos de PVC esterilizados em Radiação Gama são habitualmente reesterilizados em EO em caso de vencimento do período de validade da esterilização, que é determinado pelo fabricante. Este estudo objetivou evidenciar a toxicidade de tubos de PVC por meio do teste de citotoxicidade pelo método da difusão em ágar em culturas celulares NCTC clone 929. Foram criados quatro grupos experimentais com 81 unidades de análise: G1, constituído de tubos in natura; G2 constituído de tubos esterilizados em Radiação Gama; G3 constituído de tubos esterilizados em EO e G4 constituído de tubos esterilizados em Raios Gama e re-esterilizados em Óxido de Etileno. Os testes foram realizados em triplicata e cada tubo foi testado de forma a representar as superfícies internas, externas e massa. Após a mensuração do halo incolor, as unidades de análise foram graduadas de acordo com os graus de reatividade biológica descritos na norma ISO 10993-5:2009. Foram consideradas citotóxicas apenas as unidades análise que obtiveram grau três ou acima. Os resultados revelaram toxicidade celular apenas no grupo G3, no qual foram observadas placas com morte de todas as células, fato que demandou repetições, conforme a metodologia adotada. Na primeira repetição houve persistência de unidades de análise capazes de causar a morte de todas as células da placa. Na segunda repetição, nenhuma unidade de análise foi classificada como citotóxica. Inferiu-se que houve falhas no processo de aeração no grupo G3 e na primeira repetição. O resultado da cromatografia gasosa dos grupos G3 e G4 atestou que os materiais de ambos os grupos estariam seguros para uso. O valor máximo dos resíduos encontrados em ambos os grupos foi idêntico, contradizendo os resultados do teste de citotoxicidade. Concluiu-se que, nas condições deste experimento, os materiais de PVC esterilizados em Radiação Gama e, consecutivamente, reesterilizados em EO não são citotóxicos e a cromatografia gasosa, utilizada isoladamente, pode produzir resultados questionáveis quanto à segurança dos materiais esterilizados em EO. / In 1967, a letter sent to the British Medical Journal reported that the re-sterilization with Ethylene Oxide (EtO) of previously irradiated Polyvinyl Chloride (PVC) formed large amounts of ethylene chlorohydrin, a highly toxic compound. Even though it did not present measured data, this letter initiated a controversy that still divide the opinion of researchers to date. To solve this doubt is relevant, as PVC products submitted to gamma radiation are usually re-sterilized with EtO, when the sterilization validity has expired, which is determined by the manufacturer. The present study aimed at assessing the toxicity of PVC tubes through the cytotoxicity test, using the NCTC clone 929 cell culture agar diffusion test. Four experimental groups were created with 81 analysis units: G1, consisting of tubes in natura; G2, consisting of tubes submitted to gamma radiation; G3, consisting of tubes submitted to EtO sterilization and G4, consisting of tubes submitted to gamma-radiation and re-sterilized with EtO. The tests were carried out in triplicate and each tube was tested in order to represent its internal and external surfaces, as well as its mass. After the measurement of the colorless halo, the analysis units were graded according to the degrees of biological reactivity described in the ISO 10993-5:2009. Only the analysis units that were considered grade 3 and above were considered cytotoxic. The results showed evidence of cell toxicity only in G3, which disclosed plaques that presented death of all cells, a fact that necessitated repetition of the experiment, according to the adopted methodology. The first repetition showed the persistence of the analysis units to cause the death of all cells in the plaque. At the second repetition, none of the analysis units was classified as being cytotoxic. It was inferred that there were failures in the process of aeration in group G3 and in the first repetition. The results of the gas chromatography of groups G3 and G4 demonstrated that the materials from both groups would be safe for use. The maximum value of residues found in both groups was identical, in disagreement with the cytotoxicity test results. It was concluded that, according to the conditions of this experiment, the PVC materials submitted to gamma-radiation and consecutively sterilized by EtO are not cytotoxic and that the gas chromatography, when used alone, can yield debatable results regarding the safety of materials sterilized with EtO.
125

Vieillissement thermique d’isolants en PVC et PELX de câbles électriques en environnement automobile / Thermal ageing of PVC and XLPE insulators used in automotive electric wires

Salivon, Tetiana 31 March 2017 (has links)
Dans l’industrie automobile, la tâche de dimensionnement des faisceauxélectriques consiste à définir au plus juste la section du conducteur métallique, ce qui augmente l’échauffement du câble par effet Joule. Or, les polymères sont les matériaux d’isolation les plus utilisés malgré leur grande sensibilité au vieillissement thermique. C’est pourquoi leur durabilité en environnement automobile doit être déterminée pour pouvoir ensuite être prise en compte lors du dimensionnement des faisceaux électriques. Dans ce but, nous avons analysé le vieillissement thermique de deux gaines d’isolation en PVC et PELX dans l’air aux températures des essais de qualification (typiquement entre 100°C et 200°C). Dans le cas du PVC, le principal mécanisme de vieillissement est la perte physique du plastifiant. La fragilisation du matériau intervient orsque la concentration de la phase de plastifiant non-dissoute, qui est ispersée sous forme de nodules dans la matrice PVC faiblement plastifiée, atteint une valeur critique de l’ordre de 0,2 mol.L-1. En revanche, dans le cas du PELX, l’oxydation conduit à la fragilisation du matériau au terme de la période d’induction, c’est-à-dire dès que la totalité des antioxydants a été consommée. Pour chaque gaine d’isolation, un modèle cinétique a été dérivé des mécanismes de vieillissement et un critère de fin de vie structural a été établi. Ce modèle donne accès au potentiel de vie restant et à la durée de vie des câbles électriques en conditions de service. / In the automotive industry, the issue of electrical harness dimensioning consists in an optimal definition of the cross-section of metallic conductors, which increases the wire heating due to Joule effect. However, polymers are the most used materials for insulation despite their high sensitivity to thermal ageing. That is the reason why their durability must be determined in automotive environment to be then taken into account during the dimensioning of electrical harness. For this purpose, we analyzed the thermal aging of two insulation sheaths made of PVC and XLPE in air at temperatures of qualification tests (typically between 100°C and 200°C). For PVC, the main ageing mechanism is the physical loss of plasticizer. The material embrittlement occurs when the concentration of the non-dissolved plasticizer phase, which is dispersed as nodules in the weakly plasticized PVC matrix, reaches a critical value of about 0,2 mol.L-1. In contrast, for XLPE, oxidation leads to material embrittlement at the end of the induction period, i.e. when the totality of antioxidants has been consumed. For each insulation sheath, a kinetic model was derived from the ageing mechanisms and a structural end-of-life criterion was established. This model gives access to the remaining life potential and lifetime of electrical cables in service conditions.
126

Étude et optimisation de l'imprimabilité de films PVC produits par calandrage et enduction / Study and optimization of the printability of PVC films produced by calendering and coating

Magnier, Romain 10 April 2015 (has links)
La qualité d'impression est une notion difficile à maîtriser. L'œil est souvent utilisé en industrie comme outil permettant de juger la qualité d'un film polymère imprimé. Afin d'atteindre un niveau supérieur de qualité, il est nécessaire de trouver un moyen pour quantifier la qualité d'impression, et ainsi permettre d'atteindre soit une qualité dite « point par point », soit une qualité dite « all-over ». Plusieurs éléments sont nécessaires à cette quantification : une image en microscopie optique de l'échantillon, ainsi qu'une valeur d'intensité moyenne et d'homogénéité de couleur, que l'on obtient grâce à un rugosimètre confocal. Ainsi nous avons pu définir, pour un support mis en forme par calandrage et un support mis en forme par enduction, les paramètres majeurs agissant sur la qualité d'impression. En termes de procédé, il apparaît que la vitesse d'impression et la pression du cylindre presseur influencent grandement l'imprimabilité. Au niveau des matériaux utilisés, la viscosité et la tension de surface de l'encre ont un effet important alors qu'en termes de support, un film calandré sera plus sensible aux variations des différents paramètres qu'un film enduit. / Printing quality idea is hard to control. In industry, eye is often used to judge the quality of a printed polymer film. In order to get a new level in terms of printing quality and get “point by point” or “all-over” quality, it is necessary to find a way to quantify printing quality. Some elements are important concerning the quantification of the printing quality: an optical microscopic image, a value of the average intensity and a value on the homogeneity of the color. We can define, for a calendered and a coated substrate, the main parameters acting on the printing quality. Printing speed and pressure of the rubber roll are the two main process parameters to act, viscosity and surface tension of the ink are the two main ink properties to act, while the calendered substrate is more sensitive to the variation of the parameters than the coated one.
127

Multifunkční dům v Ledči nad Sázavou / Multifunctional Building in Ledeč nad Sázavou

Nevím, Václav January 2017 (has links)
This thesis concerns the design documentation multifunctional house in Ledeč of the town. The building has four floors and no basement.The building is designed as a brick building from Porotherm in plan a rectangular shape with a flat roof. Roofing will be made of soft PVC gray. The ground floor will be located premises for commercial purposes and the other three floors will be used for accommodation. The house is located on undeveloped land with the ground plane. On land will also be established with a capacity of 36 parking lots for cars.
128

Propriétés d'écoulement de suspensions concentrées de particules de PVC et leur lien avec la physico-chimie du système / Flow properties of PVC-particles concentrated suspensions and their relation to physico-chemistry of the system

Chatté, Guillaume 18 September 2017 (has links)
Nous étudions des suspensions concentrées de particules non-colloïdales de PVC. Ces suspensions, appelées plastisols, sont utilisées principalement pour la fabrication de revêtements de sols.Elles présentent notamment un phénomène de rhéoépaississement (hausse de la viscosité en cisaillant). Nous montrons que cela provient des forces de frottement entre particules. En effet, à l’aide d’un microscope à force atomique, nous sommes pour la 1ère fois capable de relier directement la contrainte macroscopique d’apparition du rhéo-épaississement à la contrainte microscopique d’apparition de la friction solide entre particules.Nous caractérisons la viscosité de la suspension jusqu’à 100 000 s-1 et nous observons qu’une plus grande polydispersité limite le rhéoépaississement. Les différences de contraintes normales N1 et N2 sont aussi mesurées. Par ailleurs, des mesures à l’aide de rayons X ou d’ultrasons ne montrent aucune migration de particules sous cisaillement.Nous montrons également que la géométrie a un fort impact sur l’écoulement de la suspension concentrée. Un entrefer plus petit provoque une baisse de la viscosité et retarde le rhéoépaississement. Une approche non-locale permet de rationaliser les résultats.La substitution de particules de PVC par des particules de CaCO3 modifie profondément la viscosité et la densité d’empilement maximum. Nous développons alors des modèles simples pour modéliser ces effets. En outre, nous mesurons l’impact sur la rhéologie d’un éventuel surfactant à la surface des particules.Nous avons pu finalement étudier des instabilités observées en étalant ces suspensions à haute vitesse. Une instabilité de surface est d’abord observée. A plus haute vitesse, un dépôt se forme en aval sur le couteau. Nous corrélons ces instabilités avec l’apparition de différences de contraintes normales. / Highly concentrated and non-colloidal suspensions consisting of micrometric PVC particles dispersed in a liquid phase, were studied. These suspensions, called plastisol, are mostly used in vinyl flooring manufacture.A key feature of these suspensions is shear-thickening, since viscosity greatly increases as a function of the applied shear rate. This phenomenon is explained as being related to frictional forces between particles. Indeed, using an Atomic Force Microscope, we were able, for the first time, to link the macroscopic stress, at which shear-thickening appears, with the microscopic stress needed to enter a frictional regime.We then characterize the suspension viscosity up to 100 000 s-1. We observed that shear thickening is lowered with a more polydisperse powder. Large normal stress differences N1 and N2 were also measured, along with shear thickening. In addition, using both X-ray radiography and ultrasound, no particle migration in the sheared suspension could be detected.We also found that geometry plays a major role in the features of the flow of concentrated suspensions. For a smaller gap, the viscosity is lower and shear-thickening is pushed to higher shear rates. A non-local approach accounts for our experimental results.Replacing a number of PVC particles with CaCO3 particles changes both the viscosity and the maximum packing fraction quite dramatically. For both of these, we developed simple models that matched quite well with the experimental data. Moreover, we elucidate the rheological changes resulting from adding surfactant at the surface of each particle type.Finally, we investigated some instabilities observed while coating at high speed. At a moderate speed, a ribbing phenomenon appears. At a higher speed, a deposit is formed on the knife (downstream). The appearance of these instabilities correlates with normal stress differences
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Optimization of the sorting process in PVC-floor recycling : Scenarios to optimize economic and environmental aspects of the upscaling sorting process

Jonsson, Emelie, Pálsson, Birkir January 2021 (has links)
Background: The industrial economy has been dominated by a one-way production and consumption model. Closing loops for materials has seen an upswing in popularity. The focus though has been on the environmental aspects instead of the economic benefits from implementing closed loops. With an increasing PVC consumption, the interest of implementing a closed loop of material management is increasing. PVC is a highly desired thermoplastic material because of its low cost and high performance. The high performance of PVC causes the materials to have a long lifetime which delays the end-of-life waste management. The option to utilize landfilling to deal with the accumulating waste has become a less acceptable option because of higher costs, environmental dangers, and decreasing availability of landfilling areas. When recycling PVC, it is important to ensure a high accuracy within the sorting process. A lower purity in the recycling process could lead to a lower quality of the material. With the increasing worldwide demand for PVC, which exceeds 35 million metric tons per year, the demand for a robust waste material management is high. Objectives: The objective with this master thesis is to provide a deeper understanding of the affects of introducing a closed loop of material management of PVC by optimizing the upscaling sorting process based on a maximization of the savings and the CO2 emission savings. Methods: An optimization model was developed based on previous literature regarding optimizing sorting processes and recycling processes. Different scenarios were set up to try to optimize the savings and CO2 emission savings for an upscaling sorting process of PVC. The scenarios were based on different changes in different variables. The model and the scenarios were implemented at a case study. The case study was made at the PVC-floor company Tarkett in Ronneby. Results: The different scenarios were compared based on their monthly savings and monthly CO2 emission savings. The results showed that when dealing with a larger volume of incomed material, a more capital-intensive solution should be implemented. It also showed that an upscaling of a sorting process in PVC-floor recycling can be financially feasible while implementing a closed loop of material management. Conclusions: The recent trend in waste material management indicates that many companies are implementing a closed loop of material management through capital-intensive sorting process to manage the increasing availability of waste. The comparisons of the different scenarios revealed that, if the monthly savings is to be optimized, there should be an increase in incomed material and the sorting process should implement a more capital-intensive solution utilizing automated sorting machines. If the monthly CO2 emission savings should be maximized, the incomed material should be maximized and handled by a labor-intensive solution. / Bakgrund: Den industriella ekonomin har dominerats av en enkelriktad produktions- och konsumtionsmodell. Att sluta kretar för material har fått en uppgång i popularitet. Fokus har dock varit på miljöaspekterna istället för de ekonomiska fördelarna med att genomföra slutna kretsar. Med en ökande PVC-konsumtion ökar intresset för att genomföra en sluten krets för materialhantering av PVC. PVC är ett mycket önskat termoplastmaterial på grund av dess låga kostnad och höga prestanda. PVC: s höga prestanda gör att materialen har en lång livslängd som försenar avfallshanteringen. Alternativet att använda deponi för att hantera det ackumulerande avfallet har blivit ett mindre acceptabelt alternativ på grund av högre kostnader, miljöfaror och minskad tillgänglighet av deponiområden. Vid återvinning av PVC är det viktigt att säkerställa hög noggrannhet inom sorteringsprocessen. En lägre noggrannhet i återvinningsprocessen kan leda till en lägre kvalitet på materialet. Med den ökande världsomspännande efterfrågan på PVC, som överstiger 35 miljoner ton per år, är efterfrågan på en robust hantering av avfallsmaterial hög. Syfte: Målet med detta examensarbete är att ge en djupare förståelse för effekterna av att införa en sluten krets för materialhantering av PVC genom att optimera uppskalning av sorteringsprocessen baserat på maximering av besparingar och CO2 utsläppsbesparingar. Metod: En optimeringsmodell utvecklades baserat på tidigare litteratur om optimering av sorteringsprocesser och återvinningsprocesser. Olika scenarier inrättades för att försöka optimera besparingarna och CO2-utsläppsbesparingarna för en uppskalning av sortering av PVC. Scenarierna baserades på olika förändringar i olika variabler. Modellen och scenarierna implementerades på en fallstudie. Fallstudien gjordes på PVC-golvföretaget Tarkett i Ronneby. Resultat: De olika scenarierna jämfördes baserat på deras månatliga besparingar och månatliga CO2-utsläppsbesparingar. Resultaten visade att när man hanterar en större volym inkommande material, bör en mer kapitalintensiv lösning implementeras. Det visade också att en uppskalning av en sorteringsprocess vid PVC- golvåtervinning kan vara ekonomiskt genomförbar samtidigt som en sluten krets av materialhantering genomförs. Slutsatser: Den senaste trenden inom hantering av avfallsmaterial tyder på att iiimånga företag genomför en sluten krets för materialhantering genom kapitalintensiv sorteringsprocess för att hantera den ökande tillgången på avfall. Jämförelserna mellan de olika scenarierna visade att om de månatliga besparingarna ska optimeras, bör det finnas en ökning av inkommande material och sorteringsprocessen bör implementera en mer kapitalintensiv lösning med automatiska sorteringsmaskiner.
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Élaboration de plastifiants ignifugeants à base de dérivés lipidiques pour formulations PVC / Elaboration of lipidic flame retardant plasticizers for PVC

Bocqué, Maëva 25 November 2015 (has links)
E PVC est l'un des polymères les plus employés dans les matériaux actuels et l'adjonction de plastifiants permet de modifier ses propriétés (température de transition vitreuse, module…) permettant ainsi l'utilisation de ce polymères dans des applications où de la souplesse est requise (textiles enduits, par exemple). Actuellement, les phtalates sont les plastifiants les plus utilisés même s'ils sont de plus en plus décriés du fait de leur toxicité. Le développement de nouveaux agents plastifiants est un domaine de recherches intenses et les matières premières bio-sourcées s'avèrent être une alternative intéressante aux plastifiants pétro-sourcés. Le travail de cette thèse se propose d'investiguer le développement de plastifiants du PVC bio-sourcés de type lipidique possédant de surcroit des propriétés ignifugeantes évitant ainsi l'ajout d'additifs supplémentaires dans les formulations de PVC devant résister au feu. Dans un premier temps, l'oléate, le linoléate de méthyle et le diacide (D18 : 1) ont été fonctionnalisés par modification chimique de leurs groupements ester et/ou de leurs insaturations pour mener à des dérivés lipidiques phosphorés. Cinq candidats plastifiants bio-sourcés ont ainsi pu être synthétisés et le scale up de la synthèse de l'un des candidats à l'échelle du kilogramme a pu être réalisé dans le cadre de cette thèse. Dans un deuxième temps, des tests de plastification du PVC avec divers candidats ont été réalisés en collaboration avec la société Serge FERRARI. L'étude des propriétés thermiques, mécaniques et thermomécaniques des films de PVC plastifiés obtenus, comparativement au plastifiant phtalate DINP et au plastifiant bio-sourcé commercial RADIA 7295, a permis d'éliminer différents candidats pour n'en finalement retenir que deux. Des profils de dégradation thermique satisfaisants, des basses valeurs de Tg, des allongements à la rupture importants (320 et 365 % respectivement) et proches de ceux obtenus avec le DINP, ont confirmé l'efficacité plastifiante de ces deux composés phosphorés bio-sourcés. Les tests au feu LOI et au cône calorimètre ont également prouvé le caractère ignifugeant de ces deux composés qui conduisent à des résultats du même ordre de grandeur que ceux atteints avec le plastifiant phosphonate commercial de référence S141 / Poly(vinyl chloride) is one of the most manufactured and consumed thermoplastics in the world. The addition of plasticizers allows modifying its properties (glass transition temperature, modulus…) and then to use this polymer for applications where flexibility is needed (coated textiles, for instance). Nowadays, phthalates are the main candidates for PVC even if they have been more and more controversed due to their possible toxicity. To substitute these petro-based plasticizers, researches are focused on alternative plasticizers based on bio-based raw materials. This PhD work proposes to investigate the development of new bio-based plasticizers for PVC, from lipidic derivatives, and having simultaneously flame retardant properties, avoiding the addition of any other additives in PVC during compounding. In the first part, methyl oleate, methyl linoleate and diacid D18 : 1 have been functionalized by modification of their ester groups and/or their doubles bonds to give phosphorylated lipidic derivatives. Thus, five bio-based plasticizers have been synthesized and the synthesis of one candidate on the scale of the kilogram has been successfully performed during this PhD work. Secondly, the plasticizing efficiency of several candidates with PVC has been evaluated in collaboration an industrial company. Thermal, mechanical and thermomechanical properties of the obtained soft PVC films were studied, in comparison with those obtained with the phthalate plasticizer DINP and the commercial bio-based plasticizer RADIA 7295. These analyses allowed the disposal of some of the bio-based plasticizers to finally keep only two candidates. Satisfying thermal degradation profiles, low Tg, and important elongation at break values (320 % and 365 % respectively) close to those obtained with DINP, confirmed the plasticizing efficiency of these two bio-based phosphorylated plasticizers. Fire tests like the LOI test and the cone calorimeter also proved the flame retardant properties of these two candidates, leading to similar results than the ones reached with the phosphonate plasticizer S141

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