Examensarbeten för kandidatexamen // Bachelor Theses
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- PostA study of electrical treeing in XLPE using wire electrodes - Impact on electrical treeing inception voltage by sample preparation and voltage stabilizers(2011) Kronlund, Linus; Kvist, Patric; Chalmers tekniska högskola / Institutionen för kemi- och bioteknik; Chalmers University of Technology / Department of Chemical and Biological Engineering
- PostAlkylering av etengas över zeolit H-betakatalysator med silica sol som bindemedel(2012) Belanovic, Dalibor; Hulting, Fredrik; Linder, Kristina; Malmström, Emil; Razavi, Saman; Uzelac, Vanja; Chalmers tekniska högskola / Institutionen för kemi- och bioteknik; Chalmers University of Technology / Department of Chemical and Biological Engineering
- PostAminering och alkylering av glycerol via Hydrogen Autotransfer(2015) Rönnberg, Louise; Jonsson, Julia; Larsson, Adam; Olsson, Joakim; Lundström, Helena; Nilsson, Victor; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Chalmers University of Technology / Department of Chemistry and Chemical Engineering
- PostAmylasers enzymatiska aktivitet i saltvattensmiljö(2011) Vimpari, Silvana; Chalmers tekniska högskola / Institutionen för kemi- och bioteknik; Chalmers University of Technology / Department of Chemical and Biological EngineeringAmylases are enzymes that digest starch by cleavage of glycosidic bonds, therby releasing glucose, maltose and/or malto-oligosaccharides. Amylase is used for biotechnological purposes such as the production of biofuels, in the food industry where starch is found naturally in cereals, but also in the paper industry and in the manufacture of detergents. The difference between α-amylase, β-amylase and glucoamylase is how they cleave starch into smaller glucose-containing units. α-amylase breaks down starch into oligosaccharides and dextrins, while β-amylase breaks down starch into maltose and amyloglucosidase to glucose. The aim of the project was to investigate how the enzyme activity of industrial purified amylases, that are commercially available, are affected by saline environments compared to freshwater conditions. Another part of the project was to isolate marine bacteria that use starch as a carbon source and thus produce amylases. This was performed by isolation and purification of the bacteria in starch medium, characterization in shake flask cultures and measurement of enzyme activity. Two strains were found that had better cell growth, released larger amounts of glucose from the starch, and showed a higher enzymatic activity than the other in seawater. The industrially produced amylases were tested for dependence on various parameters such as pH, temperature and enzyme activity. α-amylase Aspergillus oryzae, β-amylase and amyloglucosidases from Aspergillus niger were activated at pH 4.8. α-amylases Bacillus subtilis and porcine were activated at pH 6.9. Enzyme activity measurments for the industrially isolated amylases showed that a number of those tested had a higher amylase activity in seawater than in freshwater whereas the α-amylases from Bacillus licheniformis and Aspergillus oryzae did not exhibit any activity in seawater. This may be due to the substances found in seawater helps to facilitate the binding of and reaction with substrates and/or stabilizes the protein structure of a beneficial form. A possible reason for the differences observed between similar amylases may be that different types of treatment processes at the manufacturing companies can provide a finished product that has a different sensitivity to ions. To use algae as a future fuel source and cultivate them in saltwater you need to have a salt-tolerant amylase that can break down large amounts of starch. More analyses of existing purified amylases is recommended as these show that there is potential to find amylases that acutally are activated better in saltwater than freshwater.
- PostAmyloidbildning av Parkinsonproteinet -synuklein i cell-liknande miljö, in vitro, med crowding agents dextran och PEG(2021) Löfgren, Emil; Pernhed, David; Pernsved, Monica; Persson, Elin; Rehnberg, Nikita; Svensson, Cecilia; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Scheers, Nathalie; Wittung-Stafshede, Penilla; Horvath, Istvan; Kumar, RanjeetAll over the world life expectancy is increasing which leads to a higher prevalence of neurodegenerative diseases such as Parkinson’s Disease. The disease is chronic and leads to slow degradation of cells in the nervous system of the brain. -synuclein is a well-studied protein which is likely involved in Parkinson’s Disease. The purpose of this project is to experimentally study the aggregation kinetics of - synuclein in regard to excluded volume effects. Different sizes and concentrations of two macromolecular crowding agents, dextran and PEG, are used to mimic the crowded cell environment. Crowded conditions and their effect on the formation of -synuclein amyloids and aggregetion kinetics, are studied through a Thioflavin T-aggregation assay. SDS-PAGE, circular dichroism spectroscopy and AFM are used to complement and validate the assay results. Higher concentrations of crowding agents generates faster aggregation of -synuclein compared to lower concentrations. However the aggregation does not always increase linearly with crowding. Certain crowding agents promote elongation while others promote alternative mechanisms such as primary or secondary nucleation. Several experiments verify the occurance of soft interactions between PEG and -synuclein. The -synuclein aggregation process is rather complex and dependent on several factors. Crowding promotes faster aggregation and morphology studies suggest the formation of amyloid fibrills. The results verify the effect of excluded volume but further research is required to determine which part of the aggregation process it primarily affects.
- PostAnalys av slam från PWR-ånggeneratorer(2021) Ewertsson, Mathilde; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Eriksson, Gunnar; Larsson, Stefan; Fredin, Marcus
- PostÅteranvändning av bottenaska från förbränning av biomassa med ilmenit som bäddmaterial(2019) Westerborn, Emma; Helldal, Alexander; Arvidsson, Emma; Dahlbom Järvinen, My; Ros, Amanda; Kjellander, Josefine; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Martinelli, Anna
- PostBildande av kol-kvävebindningar genom metallkatalyserade reaktioner(2014) Bylund, Jennifer; Damgaard, Caroline; Larsson, Mikael; Luong, Staffan; Melkersson, Jenny; Öjerborn, Johan; Chalmers tekniska högskola / Institutionen för kemi- och bioteknik; Chalmers University of Technology / Department of Chemical and Biological Engineering
- PostBiofysikaliska studier av amyloida proteinfibrillers kompaktering(2014) Bengtsson, Matilde; Nassif, Jessy; Rundberg, Lisa; Schmidt, Eneas; Sundin, Elin; Svensson, Emelie; Chalmers tekniska högskola / Institutionen för kemi- och bioteknik; Chalmers University of Technology / Department of Chemical and Biological Engineering
- PostCatalyzed production of alkenyl succinic anhydride(2011) Englund, Mattias; Chalmers tekniska högskola / Institutionen för kemi- och bioteknik; Chalmers University of Technology / Department of Chemical and Biological Engineering
- PostCementation as a means for leachate liquor purification(2015) Söderqvist, Frida; Larsson, Anton; Ljungberg, David; Atterfelt, Joakim; Gustafsson, Gabriel; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Chalmers University of Technology / Department of Chemistry and Chemical Engineering
- PostCrosslinking and stability of ethylene copolymers(2010) Blomsten, Ida; Chalmers tekniska högskola / Institutionen för kemi- och bioteknik; Chalmers University of Technology / Department of Chemical and Biological Engineering
- PostDermal Drug Delivery of Gold Nanoparticles in Cubic Phase(2012) Albrektsson, Andreas; Japlin, Maria; Chalmers tekniska högskola / Institutionen för kemi- och bioteknik; Chalmers University of Technology / Department of Chemical and Biological Engineering
- PostDNA-interkalering av kirala ruteniumkomplex med liganden 6,7-dicyanodipyridoquinoxalin(2015) axelsson, john; Karlsson, Louise; Olsson, Oliver; Romberg, Erik; Skogman, Emma; Strand, Lisa; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Chalmers University of Technology / Department of Chemistry and Chemical Engineering
- PostEffect of Ni-content on oxide scale microstructure of FeCr model alloys after breakaway corrosion at 600°C(2018) Brunström, Marcus; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Svensson, Jan-Erik; Jonsson, Torbjörn; Olivas, AndreaThe world is presently enduring high amounts of greenhouse gases, thus the importance of finding eco-friendly alternatives for power production is growing for CO2 emissions to be decreased. Combustion of biomass and waste is a sustainable alternative to the traditional fossil resources, although it faces some problems along with a lower efficiency. The combustion of biomass and waste creates a corrosive environment due to the heterogeneous composition which can be controlled if the temperature is kept low. If the propagation of the corrosion attack in a boiler for these sustainable resources can be better understood it could help select a cost-efficient alloy that can endure a higher temperature. This would make power production with biomass and waste better compare with the fossil resources in terms of electric efficiency. For this purpose, Fe-18Cr-Ni model alloy coupons with varying Ni content (0-10%) were prepared, analyzed and subjected to exposure at 600°C in an aggressive environment to investigate the oxide microstructure after breakaway corrosion. Furthermore, an oxide thickness was chosen as a target for all alloys to facilitate the comparison of oxide microstructure. The conditions of exposure were 5% O2, 95% N2 with a 1 mg/cm2 K2CO3 deposit on the samples. The oxidation times were calculated according to the intended oxide thickness. Comparable results from other studies with different conditions of exposure are also discussed. Analyzes were done by means of SEM, BIB, EDX, XRD and TG. Samples were seen to show decreasing oxidation rate and mass gain with increasing amounts of Ni in this study. While the 5% Ni alloy showed relatively long incubation time, the 10% Ni alloy showed none which indicates a stable oxide growth for content around 10%. A stable oxide growth could be seen in the austenitic alloys, this could be seen in a 10% Ni sample but partly also in the 5% Ni sample. Replicating an oxide thickness acquired in the TG proved to be difficult due to differences in the equipment and deviations in combination with incubation time. Good performance of the austenitic alloys is seen but seemingly this is temperature dependent and ferritic alloys will perform better at 800°C.
- PostElectrical Treeing in XLPE(2012) Hällqvist, Oscar; Chalmers tekniska högskola / Institutionen för kemi- och bioteknik; Chalmers University of Technology / Department of Chemical and Biological Engineering
- PostElektrokemisk regeneration av perjodat för skalbar produktion av dialdehydcellulosa (DAC)(2022) BETÜL, Ahmed; Blom Larsen, Alexander; Carlunger, Emil; Johansson, Hampus; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Markovic, Nikola; Westman, GunnarM¨anniskan ¨ar idag beroende av fossila r˚avaror f¨or produktion av br¨anslen och material. I ¨over g˚angen till ett mer h˚allbart samh¨alle spelar den kemitekniska industrin en stor roll att ers¨atta fossila produkter med f¨ornybara alternativ. Derivat av cellulosa har de senaste ˚aren uppkommit som potentiella substitut f¨or olika plaster. Ett av dessa derivat ¨ar dialdehydcellulosa, DAC, som kan bildas i en redoxreaktion d¨ar tv˚a hydroxylgrupper per cellulosamonomer oxideras till aldehydgrupper med perjodat, IO− 4 , som oxidationsmedel. Syftet med denna studie var att unders¨oka m¨ojligheten att elektrokemiskt regenerera perjodat fr˚an jodat, IO− 3 , f¨or att ˚astadkomma en h˚allbar, effektiv och skalbar process f¨or produktion av DAC fr˚an cellulosa. Metoden j¨amf¨ordes mot den mer bepr¨ovade kemiska regenerationen d¨ar hypoklorit anv¨ands f¨or att ˚aterbilda perjodat. Vidare analyserades vilka biprodukter som erh˚alls i reaktionerna samt deras inverkan p˚a regenerationseffektiviteten. I den kemiska regenerationen uppn˚addes inga framg˚angsrika resultat att regenerera perjodat, vilket framkom av m¨atningar med UV-Vis. F¨ors¨oken visade ¨aven p˚a stor spridning av v¨arden, vilket tyder p˚a l˚ag repeterbarhet. Resultat fr˚an Spec-EL visar att det i den elektrokemiska regenerationen, ut¨over perjodat, bilda des vad som f¨ormodas vara jodradikaler, I• . Dessa f¨orv¨antas ha h¨arstammat fr˚an jodidjoner, I−, som uppkommit redan i cellulosaoxidationen. De reaktiva jodradikalerna orsakar vidare interak tioner med jodat och bildar hypojodsyra, HIO, som f¨ors¨amrar regenerationseffektiviteten. Det potentialintervall som gav upphov till h¨ogst regenerationseffektivitet fastst¨alldes till 1.10–1.15 V
- PostEnzymatisk extrahering och konvertering av lignin för framtida bioraffinaderier(2015) Bäckberg, Christoffer; Hagelberg, Arvid; Johansson, Rebecka; Kullberg, Linn; Samuelsson, Louise; Sundström, Clara; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Chalmers University of Technology / Department of Chemistry and Chemical Engineering
- PostExploring the cytotoxicity of polycations(2022) Brunke, Julia; Stjern, Johanna; Chalmers tekniska högskola / Institutionen för kemi och kemiteknik; Ström, Anna; Axelsson, OskarIn the delivery of genetic material in vitro, such as mRNA-vaccines, non-viral vectors are used as the transporting system. To enable the full potential of the vectors, a positive charge on the surface is necessary, which has been proven to have cytotoxic effects. The aim is to, with polyethylene glycol with a tosylate group (mPEG-tosylate), coat the positive charge and simultaneously keep the necessary charge for the desired application. In this thesis, the cytotoxic effect of a synthesized polycation and polycations coated with mPEG-tosylate are investigated. A three step synthesis was made and tested with multiple methods to confirm the occurrence of each step and the last step was tested for its cytotoxic effect. To coat a hyperbranched polyester mPEG-tosylate was used, this was also tested with several analysis methods, and the cytotoxic effects were evaluated. The results confirm that all 3 steps of the synthesis did occur and the cytotoxic effect of the polycation was visible. It also confirms that the coating with PEG was successful and the cytotoxic effect decreased. These results suggest that further studies can be necessary, in case of what the degree of PEGylation versus the necessary charge of the polycation ratio is.
- PostExtraktion och kemisk modifering av hemicellulosa(2014) Claesson, Britta; Sjöstrand Dahlberg, Jacob; Oberüller, Jacob; Sundberg, David; Sirén Gustafsson, Lisa; Sörensen, Alexander; Chalmers tekniska högskola / Institutionen för kemi- och bioteknik; Chalmers University of Technology / Department of Chemical and Biological Engineering