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Effect of Chemical Disinfection on Chitosan Coated PMMA and PETG Surfaces—An In Vitro StudyWalczak, Katarzyna, Thiele, Jessica, Geisler, Daniel, Boening, Klaus, Wieckiewicz, Mieszko 12 June 2018 (has links) (PDF)
In oral sciences, chitosan application is of interest due to its antimicrobial and hemostatic activity. Chitosan coating of dentures and other intraoral devices could be beneficial for treatment of denture stomatitis or in the management of postoperative bleeding. Disinfection of dentures and prosthodontic materials is crucial before their use in patients. This study investigated the influence of chemical disinfectants on chitosan-coated surfaces. A total of 100 specimens were made: 50 of PMMA (polymethyl methacrylate), and 50 of PETG (polyethylene terephthalate glycol-modified) material and coated with 2% chitosan acetate solution. In each material, 5 groups (10 specimens each) were established and disinfected with Printosept-ID (L1), MD 520 (L2), Silosept (L3), or Dentavon (L4), or stored in distilled water (L0, control group). After disinfection, all specimens underwent abrasion tests (30,000 cycles in a tooth-brushing simulator). Areas without chitosan coating were measured by digital planimetry both before and after the disinfection/abrasion procedure and a damage-score was calculated. Regarding chitosan coating, the statistical analysis showed a significant influence of the disinfectants tested and significant differences between disinfectants (p < 0.05). Chitosan coating was most stable on PMMA and PETG after disinfection with MD 520 (L2). Otherwise, active oxygen containing disinfectants (L3, L4) led to the greatest alterations in the chitosan coating.
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Effect of Chemical Disinfection on Chitosan Coated PMMA and PETG Surfaces—An In Vitro StudyWalczak, Katarzyna, Thiele, Jessica, Geisler, Daniel, Boening, Klaus, Wieckiewicz, Mieszko 12 June 2018 (has links)
In oral sciences, chitosan application is of interest due to its antimicrobial and hemostatic activity. Chitosan coating of dentures and other intraoral devices could be beneficial for treatment of denture stomatitis or in the management of postoperative bleeding. Disinfection of dentures and prosthodontic materials is crucial before their use in patients. This study investigated the influence of chemical disinfectants on chitosan-coated surfaces. A total of 100 specimens were made: 50 of PMMA (polymethyl methacrylate), and 50 of PETG (polyethylene terephthalate glycol-modified) material and coated with 2% chitosan acetate solution. In each material, 5 groups (10 specimens each) were established and disinfected with Printosept-ID (L1), MD 520 (L2), Silosept (L3), or Dentavon (L4), or stored in distilled water (L0, control group). After disinfection, all specimens underwent abrasion tests (30,000 cycles in a tooth-brushing simulator). Areas without chitosan coating were measured by digital planimetry both before and after the disinfection/abrasion procedure and a damage-score was calculated. Regarding chitosan coating, the statistical analysis showed a significant influence of the disinfectants tested and significant differences between disinfectants (p < 0.05). Chitosan coating was most stable on PMMA and PETG after disinfection with MD 520 (L2). Otherwise, active oxygen containing disinfectants (L3, L4) led to the greatest alterations in the chitosan coating.
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Jednostupňová převodovka vyrobená 3D tiskem / A single-speed gearbox made by 3D printingHykolli, Denis January 2021 (has links)
The aim of these theses was the creation of a single-stage gearbox by additive technology FDM / FFF. By chosen values was made dimension calculation for gears. The 3D model of the gearbox was designed in 3D software Autodesk Inventor. Single parts were produced on an FDM 3D printer by Prusa Research. Manufacturing programs for parts were prepared in PrusaSlicer. These programs were used for producing individuals parts on 3D Printer. Transparent material and printing parameters for the top of the gearbox were chosen by visual test and test of light intensity. The total cost of model production is calculated in the work. The result of these is a completely working model of a single-stage gearbox with a transparent top of the gearbox.
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Materialval, konstruktion och parametrar för 3D-utskrift / Material selection, design, and parameters for 3D-printsMalmgren, Elina, Olofsson, Ivar January 2024 (has links)
Detta examensarbete handlar om framställandet av en dokumentation för konstruktörer inom området 3D-skrivning. Arbetet är ett uppdrag från elbilstillverkaren Ecoist i syftet att underlätta för företag med begränsad kunskap och erfarenhet inom 3D-utskrifter att utnyttja tillverkningsmetoden för sina produkter. Dokumentationen skall innehålla riktlinjer för materialval, konstruktionsprinciper, och inställningar för 3D-utskrifter. För att begränsa arbetet till tidsramen läggs fokus på en typ av skrivare. Den valda typen är FDM eftersom det är den bedöms vara mest tillgängliga, både i pris och utbud. De material och dess egenskaper som betonas i dokumentationen är ASA, PETG, PLA, PP och TPU. Det huvudsakliga arbetet kommer främst innefatta faktainsamling och sammanställning från befintliga information, men även laborationer med 3D-skrivare. Kapitelindelningen i dokumentationen är strukturerad för att följa konstruktörens arbetsprocess. Den inleds med materialval, fortsätter med konstruktion och avslutas med inställningar för 3D-skrivare. I materialegenskaper behandlas de grundläggande egenskaperna hos olika material som används inom 3D-utskrift, med särskilt fokus på deras hållfasthet, miljöpåverkan, användningsområde samt för- och nackdelar. Konstruktionsriktlinjer handlar om utformning av detaljer, inklusive minsta detaljtjocklek, hantering av överhäng, fasning, efterbearbetning, integrering av fästelement samt toleranser mellan närliggande delar. Fokus ligger på att säkerställa att detaljerna är konstruerade för att vara hållbara och funktionella efter tillverkning med 3D-skrivare. Inställningar för 3D-skrivare handlar om STL-filer, olika typer av ifyllnadsmönster samt vanliga defekter och åtgärder för att motverka dem. Vidare behandlas materialspecifika inställningar för optimal justering av 3D-skrivaren. Vid utformningen av dokumentet läggs mest fokus på utseende och läsbarhet, samt ordning och struktur genom färgval, text/tabellspresentation och anpassandet av dokumentet för både fysiskt och digitalt exemplar. Hela dokumentationen finns i bilaga 1. / This thesis focuses on creating documentation for designers in the field of 3D printing. The project is commissioned by the electric car manufacturer Ecoist with the aim of helping companies with limited knowledge and experience in 3D printing to utilize this manufacturing method for their products. The documentation will include guidelines for material selection, design principles, and 3D printing settings. To fit the project within the given timeframe, the focus is limited to one type of printer. The selected type is FDM, as it is considered the most accessible in terms of price and availability. The materials and their properties emphasized in the documentation are ASA, PETG, PLA, PP, and TPU. The main work will primarily involve gathering and compiling information from existing sources, but also conducting experiments with 3D printers. The chapters in the documentation are structured to follow the designer's workflow. It begins with material selection, continues with design, and concludes with 3D printer settings. In material properties, the basic characteristics of different materials used in 3D printing are covered, with a particular focus on their strength, environmental impact, areas of use, as well as their advantages and disadvantages. Design guidelines involve the configuration of details, including minimum detail thickness, handling of overhangs, chamfering, post-processing, integration of fasteners, and tolerances between adjacent parts. The focus is on ensuring that the details are designed to be durable and functional after manufacturing with a 3D printer. 3D printer settings cover STL files, different types of infill patterns, and common defects along with countermeasures to avoid them. Furthermore, material-specific settings for optimal adjustment of the 3D printer are presented. In the design of the document, the emphasis is on appearance and readability, as well as order and structure through the choice of colors, text/table presentation, and adapting the document for both physical and digital copies. The entire documentation is included in Appendix 1.
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Výpočtové modelování procesu 3D tisku součástí z PET-G materiálu / Computational modeling of 3D printing structures made of PET-G materialMichálek, Mojmír Cyril January 2020 (has links)
Master’s thesis deals with computational modeling of 3D printing process done by FDM method made from PETG material using finite element method. Research section contains a brief description of 3D printing process modeling possibilities using finite element method and summarizes fundamental mechanical properties of thermoplastics. In practical section there is an evaluation of specimens printed of PETG material tensile tests. Further there is performed a sensitivity analysis of various influences on vertical imperfection of printed part Idler and is done its design modification, which is based on results of this analysis.
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Experimental and Modeling Study of Gas Adsorption in Metal-Organic Framework Coated on 3D Printed PlasticsDube, Tejesh C. 05 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Metal-organic frameworks (MOFs) are a class of compounds consisting of metal ions or clusters coordinated to organic ligands in porous structure forms. MOFs have been proposed in use for gas adsorption, purification, and separation applications. This work combines MOFs with 3D printing technologies, in which 3D printed plastics serve as a mechanical structural support for MOFs powder, in order to realize a component design for gas adsorption. The objective of the thesis is to understand the gas adsorption behavior of MIL-101 (Cr) MOF coated on 3D printed PETG, a glycol modified version of polyethylene terephthalate, through a combined experimental and modeling study. The specific goals are: (1) synthesis of MIL-101 (Cr) MOFs; (2) nitrogen gas adsorption measurements and microstructure and phase characterization of the MOFs; (3) design and 3D printing of porous PETG substrate structures; (4) deposition of MOFs coating on the PETG substrates; and (5) Monte Carlo (MC) modeling of sorption isotherms of nitrogen and carbon dioxide in the MOFs.
The results show that pure MIL-101 (Cr) MOFs were successfully synthesized, as confirmed by the scanning electron microscopy (SEM) images and X-ray diffraction (XRD), which are consistent with literature data. The Brunauer-Emmett-Teller (BET) surface area measurement shows that the MOFs samples have a high cover- age of nitrogen. The specific surface area of a typical MIL-101 (Cr) MOFs sample is 2716.83 m2/g. MIL-101 (Cr) also shows good uptake at low pressures in experimental tests for nitrogen adsorption. For the PETG substrate, disk-shape plastic samples with a controlled pore morphology were designed and fabricated using the fused
deposition modeling (FDM) process. MOFs were coated on the PETG substrates using a layer-by-layer (LbL) assembly approach, up to 30 layers. The MOFs coating layer thicknesses increase with the number of deposition layers. The computational model illustrates that the MOFs show increased outputs in adsorption of nitrogen as pressure increases, similar to the trend observed in the adsorption experiment. The model also shows promising results for carbon dioxide uptake at low pressures, and hence the developed MOFs based components would serve as a viable candidate in gas adsorption applications.
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Systematics in Sileneae (Caryophyllaceae) – Taxonomy and Phylogenetic patternsEggens, Frida January 2006 (has links)
The focus for the first part of the thesis is on the systematics of species belonging to Silene subgenus Silene. Phylogenetic relationships are inferred from DNA sequences from both the plastid (the rps16 intron) and the nuclear (ITS, intron of the RPB2 gene) genomes. Silene section Rigidulae is shown to be non-monophyletic in its previous circumscription, but instead consisting of six separate clades, each correlated to the geographical distribution of the included species. The taxonomic consequences for each clade are discussed. One of the clades is recognized as a new section and described as Silene sect. Arenosae sect. nov. The morphological descriptions of the species are formalized using a novel implementation of the Prometheus Description Model. Two proposals are included in the thesis, one to reject the name Silene polyphylla L., which is a senior synonym to S. portensis L. Silene linearis Decne. is proposed for conservation against the rarely used S. linearis Sweet. Silene antirrhina, a weedy American annual, is strongly supported as sister to the Hawaiian endemic species of Silene, suggesting an American origin for these. Two of the endemics have evolved woodiness after introduction to Hawaii. In the second part of the thesis we use four nuclear DNA regions, (introns from RPA2, RPB2, RPD2a, RPD2b), and the chloroplast psbE-petG spacer. A framework is developed to evaluate different phylogenetic explanations for conflicting gene trees, where divergence times are used to discriminate among inter- and intralineage processes. The incongruences observed regarding the relationships among the three major lineages of Heliosperma are best explained by homoploid hybridization. The pattern regarding the origin of Heliosperma itself is more complicated and is likely to include several reticulate events. Two lineages have probably been involved in the origin of Heliosperma, one leading to Viscaria and Atocion and the other to Eudianthe and/or Petrocoptis.
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