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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.
1

Extraktion och analys av PAH : En studie kring kontamineringshastigheten i mark

Nilsson, Karolina January 2020 (has links)
Polycyclic Aromatic Hydrocarbons (PAH) are an organic compound group consisting of cyclic molecules of two or more condensed benzene rings. All PAH are toxic to living organisms and their toxicity increases with increasing molecular weight. PAH are classified as environmental toxins but are currently not prohibited from emitting. The absence of a ban is based on the fact that the emission sources are difficult to eliminate. The present emissions mainly stem from wood burning, where heating is the primary purpose. Historically, PAH have also been released from various industrial activities. PAH are formed by incomplete combustion of organic matter at temperatures around 600°C. Thousands of tonnes are released annually and deposite over time in soils. The larger compounds become relatively immobile due to their unpolar properties. The longer the deposition takes place, the harder the PAH bind to the organic matter in the soil and cause that the decontamination work becomes more difficult over time. The remediation work is costly and because emissions are ongoing, this means that land that has been cleaned up in the long term will be re-contaminated.   The original purpose of this study has been to investigate the PAH contamination rate in a specific soil area. Originally, the purpose was also to investigate which factors affect the development of the contamination rate and potentially make the calculation work more difficult. Hypothetically, an average contamination rate could be obtained by combining measured concentrations of the PAH-16 standard from previous measurements at the same location with a current concentration from the same area plotted against time. However, measured values ​​from repeated measurements are missing. Thus, the recontamination rate at present cannot be calculated, at least not by this method. As part of future studies, it would be advisable to start taking soil samples, analyzing the PAH-16 and storing the values ​​in an existing environmental database in order to be able to monitor concentrations in soils over time. Part of the problem with this is that it is difficult to take a test at exactly the same location twice and concentrations can differ markedly even in small areas. A method for the precise selection of sampling site would therefore be appropriate to develop. The study describes the problems that are found in connection with extraction and analysis of PAH. In the extraction and analysis work itself, the most critical elements have been shown to be to extract all PAH substance from the soil sample and subsequently to avoid laboratory-related losses and to detect all compounds in the analysis. The study also reports on a number of factors that make it difficult to calculate the recontamination rate in the absence of measurement series missing.
2

Optimering av en hydraulisk sprayfärgningsprocess med hjälp av förbehandlingar / Optimization of a hydraulic spray dyeing process with help of pretreatments

Ovander, Asta, Hallberg, Saga January 2023 (has links)
Textilindustrin har under de senaste åren vidtagit drastiska åtgärder för att ställa om till en mer hållbar industri och därav möta målen för Agenda 2030. Denna undersökning syftar till att förbättra den resurssnåla hydrauliska sprayteknikens infärgning på ullvävar med hjälp av två resurssnåla förbehandlingar, plasmateknologi och ultraljudsbad. Färgklasser som används är syrafärg och reaktivfärg. Efter litteratursökning har försök utfärdats för att optimera de båda metoderna med ändamål att en mer intensiv och jämnt fördelad färg ska framträda. Inställningar gällande både ultraljudsbehandlingen och plasmateknologin diskuteras såväl som möjligheten till att effektivisera färgrecepten. Resultaten presenteras efter utförda tester på vätbarhet och färgmätningar innefattandes färgförändring och färgstyrka. Underlagen för signifikanta skillnader är bristfälliga men vissa tendenser på förbättring gällande alla avseenden kan urskiljas, dock utan slutsats om optimala inställningar. Bäst effekt återfinns i färgstyrkan för båda behandlingarna oavsett färgklass. Tas däremot alla tester i beaktande dras slutsatsen att plasmabehandlingen bäst möter de optimala egenskaperna som ullvävarna bör anta för en godtagbar infärgning. Vätbarhet, som syftar till materialets hydrofilitet, visar på betydligt bättre resultat för de plasmabehandlade proverna än för ultraljudsbehandlade, dock inte i den mån för att tillgodose problemet. Trots detta har de båda förbehandlingarna potential till att uppfylla syftet med studien, men ytterligare forskning och vidare tester krävs för att kunna implementera dessa i industrin. / In recent years, the textile industry has taken drastic measures to transition to a more sustainable industry and thus meet the goals of the 2030 Agenda. This study aims to improve the resource efficient hydraulic spray dyeing technique on wool fabrics using two resource efficient pretreatments: plasma technology and ultrasonic bath. The dyes used are acid dyes and reactive dyes. After a literature review, lab tests have been conducted to optimize both methods with the aim of producing a more intense and evenly distributed colour. The settings of both the ultrasonic and the plasma treatment are discussed as well as the possibility of streamlining the colour recipes. The results are presented after performing wettability tests and colour measurements including colour change and colour strength. There is no evidence for significant differences but tendencies for improvement in all aspects can be differenciated, however without a conclusion on optimal settings. The best effect is found in regards the colour strength for both treatments irrespective of dye class. However, if all tests are taken into account, it can be concluded that the plasma treatment meets the optimum properties that wool fabrics should adopt for an acceptable dyeing. Wettability, which refers to the hydrophilicity of the material, shows significantly better results for the plasma treated samples than for the ultrasonic treated ones, although not to the extent of satisfying the problem. Nevertheless, both pretreatments have the potential to fulfill the purpose of the study, but further research and testing is required to implement them in the industry.

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