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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.
51

Conceptualizing an automated sorting system for the recycling of plastic-floors

Abdulkarim, Abrahim, Al Outa, Nima Nova January 2020 (has links)
Background Tarkett AB Ronneby (Sweden) is a flooring solutions company, recognized for the manufacturing and recycling of homogeneous plastic flooring. Tarkett AB recycles mainly installation spill and manufacturing defects. However, Tarkett AB is considering widening its recycling capabilities to include old and torn plastic floors which may contain impurities and banned substances or plastic floors of competing brands. To accomplish this, Tarkett is considering a completely new recycling line with an automated sorting process instead of the current manual process. Thus, Tarkett proposes a dissertation to conceptualize a new automated sorting system with added capacity and increased functionality. Purpose This work aims to investigate the current sorting process and introduce conceptual solutions for a new automated sorting process capable of identifying and separating plastic floors according to the manufacturer, type, condition, and external waste by using existing technology. Method The methods and tools used in this work are mainly based on a modified product development process. Starting with data collection of the current sorting process, performing a need-finding, and extracting requirements for an automated sorting process, investigating relevant technology, evaluating technology based on scientific literature and tests. The testing was conducted in collaboration with two companies. Near-infrared scanners were tested with Holger AB, while pattern recognition systems were tested with Vision-Geek. Finally, three concepts for the automated sorting process were developed and shown through flow charts and 2D-3D illustrations. Results The results of this work showed that it was possible to use near-infrared and pattern recognition for the separation of plastic floors. Besides, three conceptual solutions for an automated sorting process were generated and showcased with schematic graphs and 2D-3D illustrations. The concepts describe how the sorting process functions and what technology is used for each step of the process. Concept 1 and Concept 2 used both pattern recognition and spectroscopy methods. While Concept 3 only used spectroscopy methods. Moreover, spectroscopy methods were used to sort plastic floors by content while pattern recognition by appearance. Conclusions Recycling of torn and old plastic flooring can be beneficial for both the environment and the recycling industry. Yet, it presents some challenges relating to reliable, fast, and nondestructive identification for sorting and separation purposes. New and proven technology such as near-infrared hyperspectral imaging and pattern recognition can be used. However, high-quality pattern and spectrum libraries of multiple plastic floors have to be created for optimal and reliable reference models. Furthermore, pattern recognition and near-infrared methods need to be tested further at an industrial scale. / Bakgrund Tarkett AB Ronneby (Sverige) är ett golvlösning företag, erkänt för tillverkning och återvinning av homogent plastgolv. Tarkett AB återvinner huvudsakligen installations spill och tillverkningsfel. Tarkett AB överväger dock att utvidga sina återvinnings förmågor till att omfatta gamla och sönderrivna plastgolv som kan innehålla föroreningar och förbjudna ämnen eller plastgolv från konkurrerande varumärken. För att åstadkomma detta överväger Tarkett en helt ny återvinnings linje med en automatiserad sorteringsprocess istället för den aktuella manuella processen. Således föreslår Tarkett ett examensarbete för att konceptualisera ett nytt automatiserat sorteringssystem med ökad kapacitet och ökad funktionalitet. Syfte Detta arbete syftar till att undersöka den nuvarande sorterings processen och introducera konceptuella lösningar för en ny automatiserad sorteringsprocess som kan identifiera och separera plastgolv efter tillverkare, typ, skick och externt avfall med befintlig teknik. Metod De metoder och verktyg som används i detta arbete är huvudsakligen baserade på en modifierad produktutvecklingsprocess. Vilket börja med datainsamling av den aktuella sorterings processen, hitta behov och extrahera krav för en automatiserad sorteringsprocess, undersöka relevant teknik, utvärdera tekniken baserad på vetenskaplig litteratur och tester. Testningen genomfördes i samarbete med två företag. Nära-infraröda skannrar testades med Holger AB, medan mönsterigenkänning system testades med Vision-Geek. Slutligen utvecklades tre koncept för den automatiserade sorterings processen och visades genom flödesscheman och 2D-3D-illustrationer. Resultat Resultaten av detta arbete visade att det var möjligt att använda nära-infraröd och mönsterigenkänning för separering av plastgolv. Dessutom genererades tre konceptuella lösningar för en automatiserad sorteringsprocess och visades med schematiska grafer och 2D-3D-illustrationer. Begreppen beskriver hur sorterings processen fungerar och vilken teknik som används för varje steg i processen. Koncept 1 och Koncept 2 använde både mönsterigenkänning och spektroskopi metoder. Medan Koncept 3 bara använde spektroskopi metoder. Spektroskopi metoderna användes för att sortera plastgolv efter innehåll medan mönsterigenkänning efter utseende. Slutsats Återvinning av sönderrivna plastgolv kan vara fördelaktigt för både miljön och återvinningsindustrin. Dock finns det några utmaningar med anknytning till pålitlig, snabb och icke-förstörande identifiering för sorterings- och separation ändamål. Ny och beprövad teknik som nästan infraröd hyperspektral avbildning och mönsterigenkänning kan användas. Emellertid måste mönster- och spektrum bibliotek av hög kvalitet av flera plastgolv skapas för optimala och pålitliga referens-modeller. Dessutom måste mönsterigenkänning och nära-infraröda metoder testas vidare i industriell skala.
52

Real-time characterization of fuel by Near-Infrared spectroscopy : Quantitative measurements of moisture content, ash content, heating value, and elemental compositions in solid biofuel mixtures

Edlund, Kajsa, Shahnawazi, Ali Ahmad January 2021 (has links)
The global energy demand supplies mainly from fossil fuels, which is neither sustainable nor environmentally friendly and aims to global warming. Therefore, both more investments in renewable energy sources such as bioenergy are required, as well as new technologies such as carbon capture and storage (CCS) to handle the emissions from existing combined heat and power (CHP) plants. In this degree project, the focus is to determine the moisture content, ash content, heating value, and elemental compositions of solid biofuel mixtures in real-time by utilizing the optical technique of near-infrared (NIR) spectroscopy. A total number of 150 samples of solid biofuel mixtures were prepared and illuminated by NIR light. All spectra of the samples were recorded in a wavenumber range of 12000 cm-1 – 400 cm-1 in a dish on a turn table which was in a moving mode with a speed of 0.5 m/s. Each sample was scanned three times to avoid, or at least minimize the deviation of the spectra and the samples were mixed between each scan to get more reliable representative spectra data. Partial least square regression models were created to analyze the spectra data. A data split was done randomly, 100 for calibration and 50 for validation. Then the data was pre-processed with different methods including multiplicative scatter correction (MSC), standard normal variate (SNV), Savitzky-Golay 1st derivative (SG 1st), Savitzky-Golay 2nd derivative (SG 2nd), and orthogonal signal correction (OSC) to reduce noise and scatter effect. The results of NIR spectra treated by OSC method obtained  , RMSE and SE of 0.900, 2.241 and 2.204, respectively for prediction of moisture content, 0.424, 0.913 and 0.922 for prediction of ash content, 0.640, 0.370 and 0.368 for prediction of heating value, respectively. The obtained prediction of  , RMSE and SE were 0.687, 0.066 and 0.058 for nitrogen, 0.636, 0.361 and 0.364 for carbon, 0.483, 0.269 and 0.270 for hydrogen, respectively. As the results shows, these models to predict the ash content and hydrogen content has a lower accuracy than what is expected in process modeling while the prediction of moisture content has the highest accuracy.
53

Molecular insight into ion interactions at charged interfaces exposing sulfonate headgroups / Molekylär insikt i joninteraktioner vid laddade gränssnitt som exponerar huvudgrupper för sulfonat

Widehammar, Hugo January 2021 (has links)
Hur elektrolytlösningar interagerar med laddade ytor är viktigt för många fenomen. I detta arbete undersöktes samspelet mellan flera joner med en negativt laddad yta som exponerade sulfonat funktionella grupper mot lösning. Särskild vikt lades på deprotoneringsbeteendet vid ytan. Samspelet mellan olika joner och sulfonatgruppen hade inte tidigare beaktats ur ett molekylärt perspektiv. Här användes ett Langmuir-monolager bestående av dokosan-1-sulfonsyra deponerat på olika elektrolytlösningar som modellsystem. För att studera molekylära interaktioner mellan ytan och elektrolyterna användes Vibrational Sum Frequency Spectroscopy (VSFS). Denna inneboende ytkänsliga teknik gör det möjligt att observera små förändringar i vibrationsenergier i sulfonagruppen vid kontakt med olika joner, här hydronium, litium, natrium och cesium. Ett av huvudsyftena med detta arbete var att jämföra de experimentellt bestämda parametrarna med teoretiska modeller av det elektriska dubbelskiktet vid laddade gränssnitt, såsom Gouy-Chapman-teorin och andra mer avancerade Poisson-Boltzmann-baserade modeller, för att utforska deras lämplighet och gränser av giltighet. Docosan-1-sulfonsyra packades snyggt i monolager, med packningstätheten ökande med starkare jonstyrka I underfasen. Två toppar i vibrationsspektra sågs för sulfonatgruppen, den symmetriska och asymmetriska sträckningen vid 1048 cm-1 respektive 1150 cm-1. Dessa band sågs blåskiftas vid bindning av litium- och natriummotjoner. Amplituden för den symmetriska sträckningen kunde kopplas direkt till mängden laddade arter. Den teoretiska Gouy-Chapman-modellen var tillräcklig att användas för relativt låga ytpotentialer (<|150mV|). För högre potentialer var motjonens storlek nödvändig att inkludera i modellen för mer exakta förutsägelser. Sulfonsyrans surhetsgrad uppmättes till att vara pKa=-1.8±0.4 och bindningskonstanterna för olika hårda joner till den sulfonatfunktionella gruppen uppskattades vara pKLi=0 och pKNa=-0.7. Däremot binder den mjuka jonen, cesium, inte till sulfonatgruppen. Implikationen är att sulfonatgruppen bör betraktas som en hård jon I enlighet med Collins lag om matchande vattenaffiniteter. / How electrolyte solutions interact with charged surfaces is essential for many phenomena in physics, chemistry and biology. In this work, the interactions of several ions with a negatively charged surface exposing sulfonate functional groups to solution were investigated. Specific emphasis was made on the deprotonation behaviour at the surface. The interplay between different ions and the sulfonate moiety had not been previously considered from a molecular perspective.  Here, a Langmuir monolayer consisting of docosane-1-sulfonic acid deposited on top of different electrolyte solutions was used as model system. To study the molecular interactions between the surface and the electrolytes, Vibrational Sum Frequency Spectroscopy (VSFS) was used. This intrinsically surface sensitive technique allows observing small changes in vibrational energies of the sulfonate functional group when in contact with different ionic species, here hydronium, lithium, sodium and cesium. One of the main objectives of this work was to compare the experimentally determined parameters with theoretical models of the electric double layer at charged interfaces, such as the Gouy-Chapman theory and other more advanced Poisson-Boltzmann based models, to explore their suitability and limits of validity. Docosane-1-sulfonic acid packed nicely into monolayers, with the packing density increasing with stronger ionic strength in the subphase. Two peaks in the vibrational spectra were seen for the sulfonate functional group, the symmetric and asymmetric stretch at 1048 cm-1 and 1150 cm-1, respectively. These bands were seen to blue-shift upon binding of lithium and sodium counterions. The amplitude of the symmetric stretch could be directly linked to the amount of charged species. The Gouy-Chapman theoretical model was adequate to use for relative low surface potentials (<|150mV|). For higher potentials, the size of the counterion was necessary to include in the model for more accurate predictions. The acidity of the sulfonic acid was measured to be pKa=-1.8±0.4 and the binding constants for different hard ions to the sulfonate functional group were estimated to be pKLi=0 and pKNa=-0.7. In contrast, the soft ion, cesium, does not bind to the sulfonate. The implication is that the sulfonate moiety should be considered a hard ion in accordance with Collins law of matching water affinities.
54

Biodegradation Experiments of Polymeric Materials: Monitoring and Analysis / Bionedbrytning av Polymera Material: Undersökning och Analys

Ojala, Sini January 2021 (has links)
Plastskräp har blivit ett global problem på grund av nedskräpning och otillräcklig avfallshantering. Användning av biologiskt nedbrytbart material kan underlätta problemet, även om det inte är en universallösning. Produkter gjorda av biologiskt nedbrytbart material skall ändå till avfallshantering eftersom nedbrytningen kan vara långvarig och variera mycket beroende av omgivningen. Därmed är användningen av biologiskt nedbrytbart material endast berättigat då det är svårt att samla in materialet eller avskilja det från organiskt material. Studiens mål var att undersöka biologiskt nedbrytbara material som kan användas i produkter som fungerar under många olika driftsförhållanden och inte kan återställas efter användning. I den litterära delen av denna studie definieras nedbrytning genom egenskaper och förhållanden som påverkar nedbrytningsprocessen. Nedbrytning av polyestrar och cellulosa och de standardprocessarna som används i nedbrytningsexperimenten betraktades. Standardprocesserna för nedbrytning studerades för att få en klarare inblick i den eftertraktade nedbrytningsgraden och de standardiserade förhållandena för nedbrytningen i olika miljöer. En sammanfattning av olika nedbrytningsexperiment och analysmetoder är också inkluderade för att försäkra att experimenten som utfördes är både giltiga och jämförbara med andra forskningsresultat inom fältet. I detta forskningsprojekt utfördes nedbrytningsexperiment i färskvatten- och hemkompostmiljöer. Målet med projektet var att bedöma ifall materialen kunde brytas ned i ett brett spektrum av miljöer, ifall de var mindre skadliga för naturen än konventionella material som används av dagens industri och för att uppskatta nedbrytningstakten. Nedbrytningstiden var 140 dagar och experimentet utfördes med 10 olika material: betecknade som A-J. Materialen analyserades 8 gånger under nedbrytningsperioden förutom materialen I och J som analyserades en gång efter 140 dagar. Materialen analyserades mekaniskt, strukturellt och termiskt med hjälp av dragprovning, FTIR och DSC. Provernas viktförändring bestämdes också. Nedbrytning observerades visuellt från provernas yta och genom mekaniska prover. Materialen som placerades i hemkomposten visade klara tecken på nedbrytning då färgen hade förändrats och förstärkningsfibrerna hade blivit synliga. Materialen som placerats i hemkompostmiljö visade också klara tecken på tillväxt av mikroorganismer och biomassa som uppstått på ytan av materialen. Sammanfattningsvist, visade materialen B, C och G de mest lovande resultaten med klara tecken på biologisk nedbrytning och de hade en snabbare nedbrytningstakt än de andra materialen som undersöktes. Material D visade klara tecken på biologisk nedbrytning på ytan men dess nedbrytningstakt var uppskattad att vara mycket långsammare. Därmed rekommenderas det att använda material A, B, D och G istället för konventionella icke biologiskt nedbrytbara material. Dessa material har potential att sänka den negativa inverkan och de långsiktiga riskerna av plastskräp för miljön. / Plastic debris has become a global crisis due to littering and misplaced waste management. The use of biodegradable materials can ease the problem, but it is not always the answer. Products made of biodegradable materials are still to be waste managed since biodegradation can be a long process and is highly dependent on the environment conditions. Hence, the use of biodegradable materials is justified only when retrieving the product after use is impossible or prohibitively expensive or separating it from organic matter is difficult. This study was made to investigate biodegradable materials that can be used in products that are operating in broad range of operational conditions and cannot be retrieved back after use in most cases. In the literature part of this study the biodegradation is defined along with properties and conditions that affect the biodegradation process. Biodegradation of polyesters and cellulose, and standards used in the biodegradation experiments were reviewed. Biodegradation standards were studied in order to have a clearer picture of the pursued degree of biodegradation and standardized properties in the biodegradation experiments. Review of different biodegradation tests and analysis methods are included as well to ensure that the experiments performed in this work are valid and comparable with other biodegradation studies.  In this study, the biodegradation experiment was conducted in freshwater and home compost environments. The aim was to determine if the materials were able to biodegrade in wide range of environments, to make sure they are less harmful than the conventional materials used in the industry and to estimate the rate of biodegradation. The duration of the experiments were 140 days with 10 different materials: A – J. The materials were analyzed 8 times during the aging period, except materials I and J, which were analyzed only once after 140 days. The samples were analyzed mechanically, structurally, and thermally using tensile test, FTIR and DSC measurements, respectively. Also, the samples weight changes were analyzed.  The degradation was visually observed from the surfaces of the samples and from mechanical testing in both experimental environments. Home compost environment showed clear signs of biodegradation where reinforcement fibers became visible and changed the color of some of the samples. Also, home compost samples had microorganisms growing on them, and biomass was developing around them. To conclude, material B, C and G had the most promising results with clear signs of biodegradation and had faster estimated biodegradation rate compared with the other studied materials. Material D had signs of biodegradation on the surface as well. However, the biodegradation rate was estimated to be much slower. In conclusion, it is recommended to use the studied materials A, B, D and G instead of the conventional non-biodegradable polymers. These materials have potential to lower the negative impact and long-term risks of plastic debris to the environment.
55

Effect of Heat Treatment on Morphology and Dielectric Properties of Polyethylene

Hoq, Md Tanbhir January 2014 (has links)
Polyethylene is used extensively as an insulating material in high voltage power cables, it is therefore important to understand the behaviour of polyethylene under different conditions. This is a study regarding the relation of heat treatment and the effect of morphological changes on the dielectric properties of polyethylene samples. Polyethylene granulates were pressed to 1 mm thick circular plaque samples that were heat treated differently. The heat treatments were conducted in a vacuum oven. Heat treated samples were tested for morphological changes with Differential Scanning Calorimetry (DSC) and dielectric property changes were studied with an IDAX 300 Dielectric Spectroscopy Analyser and a TREK 30/30 high voltage amplifier, allowing measurements in the frequency range 0.1 mHz – 100 Hz for voltages up to 30 kV. The experimental results were analysed to understand the co-relation among these parameters. A literature review has been conducted on polyethylene morphology to understand their behaviour under different annealing conditions. A phenomenon that has been noticed during the experiments is that the samples swell with annealing; the thickness change effects the dielectric measurements as well. For this reason an extensive study has been conducted on the effect different temperature and time of heat treatment had on the samples. Heat treatment has effects on the properties of polyethylene samples, but the effect of heat treatment was not only on the morphology but also on the physical dimension of the samples. The samples change their thickness with heat treatment along with their morphology. The effect of morphological changes on the dielectric property of polyethylene samples has not been found to be eminent. This study was focused on relatively thicker samples (1 mm) compared to the existent scientific literature (0.1-0.2 mm). There are very limited research literatures available on the relation of morphology and electrical properties of polyethylene; this work is an attempt to contribute to the knowledge. Also the effect of samples swelling with annealing and its effect on electric measurements is not found in existing literatures. This work will also contribute understanding the effect of sample swelling on measurements. / Polyeten används i stor utsträckning som ett isolermaterial i högspänningskablar, och därför är det därför viktigt att förstå beteendet hos polyeten under olika förhållanden. Detta är en studie angående relationen mellan värmebehandling och effekten av morfologiska förändringar av de dielektriska egenskaperna hos polyeten. Polyeten granulat pressades till 1 mm tjocka cirkulära skivor som sedan värmebehandlades olika. Värmebehandlingarna utfördes i en vakuumugn. De värmebehandlade proverna testades för morfologiska förändringar med differentiell svepkalorimetri (DSC) och de dielektriskaegenskaperna studerades med en IDAX 300 Dielektrisk spektroskopi Analysator och en TREK 30/30 högspänningsförstärkare, vilken tillåter mätningar i frekvensområdet 0,1 mHz - 100 Hz för spänningar upp till 30 kV. De experimentella resultaten analyserades för att förstå relationen mellan dessa parametrar. En litteratur har utförts på polyeten morfologi för att förstå deras beteende under olika anlöpningsförhållanden. Ett fenomen som har uppmärksammats under experimenten är att proverna sväller med anlöpningenÄven tjockleken påverkar de dielektriska mätningar. Av denna anledning utfördes en omfattande studie av effekten av olika temperatur och tid för värmebehandling hade på proverna. Värmebehandling har effekter på egenskaperna för polyetenprover, men effekten av värmebehandlingen var inte bara på morfologin, utan också på den fysiska dimensionen av proverna. Effekten av morfologiska förändringar på den dielektriska egenskapen hos polyetenprover har inte befunnits vara framstående. Denna studie var inriktad på relativt tjockare prover (1 mm) jämfört med den existerande vetenskapliga litteraturen (0,1-0,2 mm). Det finns mycket lite litteratur kring relationen mellan morfologi och elektriska egenskaper hos polyeten; detta arbete är ett försök att bidra till kunskapen. Även effekten av provernas svällande efter anlöpning och dess effekt på dielektriska mätningar finns befintliga litteraturen.
56

Metal Particles – Hazard or Risk? Elaboration and Implementation of a Research Strategy from a Surface and Corrosion Perspective

Midander, Klara January 2009 (has links)
Do metal particles (including particles of pure metals, alloys, metal oxides and compounds) pose a hazard or risk to human health? In the light of this question, this thesis summarizes results from research conducted on metal particles, and describes the elaboration and implementation of an in vitro test methodology to study metal release from particles through corrosion and dissolution processes in synthetic biological media relevant for human exposure through inhalation/ingestion and dermal contact. Bioaccessible metals are defined as the pool of released metals from particles that potentially could be made available for absorption by humans or other organisms. Studies of bioaccessible metals from different metal particles within this thesis have shown that the metal release process is influenced by material properties, particle specific properties, size distribution, surface area and morphology, as well as the chemistry of synthetic biological test media simulating various human exposure scenarios. The presence of metal particles in proximity to humans and the fact that metals can be released from particles to a varying extent is the hazard referred to in the title. The bioavailable metal fraction of the released metals (the fraction available for uptake/absorption by humans through different exposure routes) is usually significantly smaller than the bioaccessible pool of released metals, and is largely related to the chemical form and state of oxidation of the released metals. Chemical speciation measurements of released chromium for instance revealed chromium to be complexed to its non-available form in simulated lung fluids. Such measurements provide an indirect measure of the potential risk for adverse health effects, when performed at relevant experimental conditions. A more direct way to assess risks is to conduct toxicological in-vitro testing of metal particles, for instance on lung cell cultures relevant for human inhalation. Induced toxicity of metal particles on lung cells includes both the effect of the particles themselves and of the released metal fraction (including bioaccessible and bioavailable metals), the latter shown to be less predominant. The toxic response was clearly influenced by various experimental conditions such as sonication treatment of particles and the presence of serum proteins. Thorough characterization of metal particles assessing parameters including chemical surface composition, degree of agglomeration in solution, size distribution, surface area and morphology was performed and discussed in relation to generated results of bioaccessibility, bioavailability and induced toxicity. One important conclusion was that neither the surface composition nor the bulk composition can be used to assess the extent of metals released from chromium-based alloy particles. These findings emphasize that information on physical-chemical properties and surface characteristics of particles is essential for an in-depth understanding of metal release processes and for further use and interpretation of bioaccessibility data to assess hazard and reduce any risks induced by human exposure to metal particles. / QC 20100803
57

Purification, functional characterization and crystallization of the PerR peroxide sensor from Saccharopolyspora erythraea

Elison Kalman, Grim January 2019 (has links)
This report summarizes the work on the cloning, expression, and purification of PerR, a metal sensing regulator from Saccharopolyspora erythraea and the subsequent characterization using small angle X-ray scattering and other biochemical methods. The report aims to provide an insight into prokaryotic metal homeostasis, provide a better understanding of how PerR works and provide valuable information for the continued work on the crystallization of PerR.

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