Dissertations / Theses on the topic 'Textile chemistry'
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Britz, Lizaan. "A comparison of the comfort properties, measured with a sweating manikin (WalterTM), of clothing containing different fibres." Thesis, Nelson Mandela Metropolitan University, 2017. http://hdl.handle.net/10948/14752.
Full textMtibe, Asanda, and Linda Linganiso. "Biocomposites from polyfurfuryl alcohol reinforced with microfibres and nanocellulose from flax fibres and maize stalks." Thesis, Nelson Mandela Metropolitan University, 2016. http://hdl.handle.net/10948/12175.
Full textSrinivasan, K. "FDAS : a knowledge-based framework for analysis of defects in woven textile structures." Thesis, Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/8671.
Full textManzlak, Derrick Anthony. "Boron Carbide Filled Neutron Shielding Textile Polymers." W&M ScholarWorks, 2007. https://scholarworks.wm.edu/etd/1539626861.
Full textKARNIK, POONAM PRAFULL. "USE OF CATIONIZED COTTON FOR TEXTILE EFFLUENT COLOR REDUCTION." NCSU, 2002. http://www.lib.ncsu.edu/theses/available/etd-20020301-132054.
Full textABSTRACTKARNIK, POONAM. Use of Cationized Cotton for Textile Effluent Color Reduction.(Under the direction of Dr. Brent Smith and Dr. Peter Hauser) The liquid effluents from the textile industry mainly consist waters colored by thedyes used in the coloring of textile yarns and fabrics. These dyes can be removed by adsorption onto adsorbing materials like cotton. Waste cotton fibers can be cationized using a quaternary ammonium compound like 3-chloro-2-hydroxypropyltrimethylammonium chloride to their cationic form. This cationic form can be used as the adsorption medium for anionic dyes like acid, direct and fiber reactive dyes.
Mittal, Khushboo Surender. "Development of Dual Functional Textile Materials Using Atmospheric Plasma Treatments." NCSU, 2009. http://www.lib.ncsu.edu/theses/available/etd-04092009-231813/.
Full textBilgen, Mustafa. "Wrinkle Recovery for Cellulosic Fabric by Means of Ionic Crosslinking." NCSU, 2005. http://www.lib.ncsu.edu/theses/available/etd-04202005-140912/.
Full textHorton, Aaron Michael. "Novel Reactive Dyes Based on Pyrimidine and Quinoxaline Systems." NCSU, 2009. http://www.lib.ncsu.edu/theses/available/etd-04302009-143537/.
Full textGoli, Kiran Kumar. "Use of Modified Cellulose for the Improvement of Water Repellency." NCSU, 2008. http://www.lib.ncsu.edu/theses/available/etd-06062008-145319/.
Full textSaunders, Joshua Daniel. "Novel Supramolecular Polyamides." NCSU, 2005. http://www.lib.ncsu.edu/theses/available/etd-07242005-213223/.
Full textLumley, Amy Catherine. "An Alternative Laundering Procedure to Predict the Durability of Flame Retardant Fabric." NCSU, 2003. http://www.lib.ncsu.edu/theses/available/etd-08192003-190154/.
Full textBridge, T. P. "Derivative spectroscopic studies on colourants used in textile technology." Thesis, Heriot-Watt University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356304.
Full textMayfield, Angela Raye. "Characterization of textile materials by near-infrared relectance spectroscopy." Thesis, Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/8616.
Full textHorn, John Christopher. "Electrophoresis of reduced polypeptides dissolved from Lincoln wool and other animal fibres." Thesis, University of Leeds, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328302.
Full textJaftha, Desiree Virginia. "South African National Accreditation System accreditation : a case study of a university of technology textile testing laboratory." Thesis, Cape Peninsula University of Technology, 2008. http://hdl.handle.net/20.500.11838/1222.
Full textThe South African Government provides support to the clothing and textile industry by making funding available through programs in the Department of Science and Technology, such as the Tshumisano Technology Stations Program. The Technology Stations Program in particular supports a Technology Station in Clothing and Textiles (TSCT) at the Cape Peninsula University of Technology (CPUT), serving the needs for technology support and skills upgrading of the industry in the Western Cape, and in some instances, nationally. The TSCT testing laboratory provides testing services to small medium and large companies in South Africa at a reduced cost. The laboratory emphasises that customers should have fabrics tested before production commences. In this regard, the company will know the quality of the fabric or garment being purchased or manufactured. The laboratory technicians and assistants undergo a 'Woolworths' certification process on their test methods on an annual basis. The Woolworths certification is customer based. The laboratory is faced on a daily bases with the problem that more and more of their customers request that the facility should seek higher 'accreditation', as opposed to the current 'certification' it currently holds. The TSCT testing laboratory in addition has a responsibility to satisfy all of its customer certification and accreditation needs. Against this background, the management of the CPUT TSCT testing laboratory is now seeking accreditation from the South African National Accreditation System (SANAS) to widen the spectrum of its testing abilities. The primary research objectives of this dissertation are: To determine what the requirements are for SANAS accreditation by the CPUT TSCT testing laboratory. To determine if the CPUT TSCT testing laboratory is subject to a forced intervention for SANAS accreditation. To determine the criteria required for the CPUT TSCT testing laboratory accreditation. To determine the benefits that could be gleaned from this accreditation. To determine the effectiveness of the laboratory system, with regard to the fact that in addition to testing, the laboratory is used for teaching and learning. Descriptive research will serve as the research type, as it will describe an existing phenomena taking place. The research will be theoretical in nature and conducted in terms of both positivistic and phenomenological paradigms. Case study research will serve as research method. Data collection for the proposed research will be conducted using questionnaires. The CPUT Clothing and Textile Technology Department will serve as sampling frame, while the sample of respondents will be drawn on the basis of probability sampling. The sample will include lecturing staff, students, industry testing customers, textile test laboratory technicians, administration and support staff, all of whom are directly involved with the operation or make use of the laboratory facilities.
Moyo, Doice. "Characterisation and optimisation of waterjet impact forces and energy parameters during hydroentanglement." Thesis, Nelson Mandela Metropolitan University, 2012. http://hdl.handle.net/10948/d1020134.
Full textPendergrass, Allan Douglas. "Process design and optimization in the bench scale production of silica fiber using the sol-gel method." Thesis, Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/8239.
Full textJain, Mukesh Kumar. "Physical and morphological changes during the conversion of acrylonitrile-based precursors to carbon fibers by Mukesh Kumar Jain." Diss., Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/8556.
Full textQian, Li-Ren. "Characterization of polyethylene terephthalate heat set carpet yarn by near infrared reflectance spectroscopy." Thesis, Georgia Institute of Technology, 1987. http://hdl.handle.net/1853/9208.
Full textBhat, Gajanan S. "Stabilization of pan-based precursors for carbon fibers by Gajanan S. Bhat." Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/10119.
Full textCaldas, Victor. "Morphology, physical and tensile properties of quench-cooled isotactic polypropylene films and spunbonded fabrics." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=40026.
Full textCross polarization/magic angle spinning (CP/MAS) nuclear magnetic resonance (NMR) spectroscopy was used to monitor morphological changes in the purely crystalline phase of quench-cooled iPP films and spunbonded fabrics during annealing. The spectra were obtained using a pulse sequence that incorporates a delay period with a reduced spin locking field prior to cross polarization. Morphological changes occurring within the purely crystalline phase of iPP were related to observations made by DSC. Upon annealing, the CP/MAS NMR spectrum of the purely crystalline phase of both iPP samples changed by a redistribution in the intensity of the various peaks within a given carbon resonance. This redistribution of intensity was found to reflect the conversion from the $ alpha sb1$ to the $ alpha sb2$ monoclinic crystal forms. It is shown that the double melting endotherm observed by DSC for the spunbonded fabrics is due to the exothermicity which is associated with this conversion. It is concentrated in the temperature region between 156 and 163$ sp circ$C.
The tensile properties of the spunbonded iPP fabrics and fibers were enhanced by the dispersion of a silica/silicone additive and by changing the resin characteristics. This additive acts as a nucleating agent for iPP under isothermal crystallization conditions. This nucleating ability manifests itself in smaller crystal sizes and higher nucleation densities in the iPP fibers and bond points. The improved tensile properties are attributed to the smaller crystal sizes which form a more homogeneously dispersed crystalline phase in the amorphous phase as well as to increase the number of load-bearing tie molecules.
Cruthers, Natasha Marie, and n/a. "Textile fibre from six cultivars of harakeke (Phormium tenax)." University of Otago. Department of Clothing and Textile Sciences, 2005. http://adt.otago.ac.nz./public/adt-NZDU20070501.135549.
Full textMorali, Eyup Kaan. "Ozonation Of A Denim Producing Textile Industry Wastewater." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612428/index.pdf.
Full textcolor=5500 Pt-Co), and to the whole effluent from a denim-producing plant before(COD=2750 mg/L
color=3950 Pt-Co) and after(COD=800 mg/L,color=3700 Pt-Co) biological treatment for degradation/detoxification purposes. Ozonation was also tried in the wastewater of the plant(COD=3100 mg/L
color=4500 Pt-Co) that would be produced after some foreseen cleaner production measures
caustic recovery and reusing of dyeing process wastewater. When applied to indigo-dyeing wastewater
ozonation provided 95% color and 61% COD removals at 1320 mg/h ozone dose within 60 minutes The optimum pH was evaluated as 4 when indigo-dyeing wastewater exposed to ozonation at different pHs(1.6-12.3). On the other side, ozonation applied as pre-treatment to the plant effluent provided 86% color and 46% COD removals with 3240 mg/h ozone dose in 70 minutes. Less satisfactory results were obtained when ozonation was tried in the wastewater after measures, with 86% color and 31% COD removals at 3960 mg/h ozone dose in 80 minutes. When applied to the biologically-treated effluent
at 420 mg/h ozone dose and within 40 minutes, ozonation removed 47% of influent COD and 96% of influent color indicating better performance of ozonation in postoxidation. In order to assess possible improvements on ozonation with the addition of H2O2, different concentrations were tried, but no significant improvement was obtained. The improvement in BOD5/COD index was also determined for the ozonetreated plant effluent to measure the effects of ozonation on biodegradability and found out that BOD5/COD ratio has improved to 0.39 from 0.22.
Chapple, Stephen Anthony. "Improving certain high performance properties of natural fibres." Thesis, Nelson Mandela Metropolitan University, 2007. http://hdl.handle.net/10948/815.
Full textJinks, Douglas David. "Drying of latex backcoated acrylic fabrics: optimization and control." Thesis, Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/11242.
Full textVargantwar, Pruthesh Hariharrao. "Preparation of ionic cellulose for wrinkle resistant fabrics." NCSU, 2007. http://www.lib.ncsu.edu/theses/available/etd-04252007-154942/.
Full textZhang, Shu. "Mechanical and physical properties of electrospun nanofibers." NCSU, 2009. http://www.lib.ncsu.edu/theses/available/etd-07102009-165411/.
Full textRex, Matthew. "ROOM TEMPERATURE FLUORESCENCE SPECTROSCOPY AS A TOOL FOR THE FORENSIC TRACE ANALYSIS OF TEXTILE FIBERS." Doctoral diss., University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4355.
Full textPh.D.
Department of Chemistry
Sciences
Chemistry PhD
Wong, Ka Chun. "Focused Ion Beam Nanomachining of Thermoplastic Polymers." Thesis, North Carolina State University, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3538536.
Full textCommercially available Ga+ focused ion beam (FIB) instruments with nanometer size probe allows for in situ materials removal (sputtering) and addition (deposition) on a wide range of material. These spatially precise processes have enabled a wide range of nanofacbrication operations (e.g. specimen preparation for analysis by scanning electron microscope, transmission electron microscope, and secondary ion mass spectrometer). While there exists an established knowledge of FIB methods for sample preparation of hard materials, but FIB methodology remain underdeveloped for soft materials such as biological and polymeric materials.
As FIB is increasingly utilized for specimen preparation of polymeric materials, it is becoming necessary to formulate an information base that will allow established FIB techniques to be generalized to this spectrum of materials. A thorough understanding of the fundamental ion-solid interactions that govern the milling process can be instrumental. Therefore, in an effort to make the existing procedures more universally applicable, the interrelationships between target material, variable processing parameters, and process efficiency of the milling phenomena are examined. The roles of beam current, distance (i.e. step size) between successive FIB beam dwell and the time it spent at each dwell point (i.e. pixel dwell time) are considered as applied to FIB nanomachining of four different thermoplastic polymers: 1. low density polyethylene (LDPE), 2. high density polyethylene (HDPE), 3. Polystyrene (PS), and 4. nylon 6 (PA6). Careful characterization of such relationships is used to explain observed phenomena and predict expected milling behaviors, thus allowing the FIB to be used more efficiently with reproducible results. Applications involving different types of polymer composite fiber are presented.
Lutseke, Nothando Sazikazi. "An investigation into the properties of cotton fibres as used in nonwoven fabrics." Thesis, Rhodes University, 1989. http://hdl.handle.net/10962/d1018241.
Full textOrpiszak, Martin. "Oxidation of cellulose to favour its dissolution in alkaline aqueous solution before regeneration into textile yarn." Thesis, KTH, Kemiteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-296556.
Full textThis master thesis is part of the Cellufil Project and aims to optimize the conditions for dissolving cellulose in aqueous sodium hydroxide solution followed by regeneration it in the form of a yarn. Previous works have shown that cellulose could be dissolved in soda at -10°C, but such conditions are not applicable at industrial scale. The objective of the present project is to work at room temperature. For that, carboxyl groups will be introduced in the cellulose chains in order to increase cellulose solubility in an alkaline aqueous medium, after this it is reprecipitated it in acidic solutions. Periodate makes it possible to oxidize the alcohol groups of cellulose on C2 and C3 positions by opening the glucose units to create two carbonyls functions (aldehyde) which can then be easily oxidized into carboxylic groups with overoxidation using sodium chlorite. A first part of the report is dedicated to the literature review on the subject, focusing on periodate oxidation. Then, a general protocol is proposed from the periodate oxidation to the regeneration of cellulose into yarn in sulfuric acid solutions. Several conditions for the periodate oxidation are tested, at different temperatures, with or without metal salts and with different oxidant dosages. The dissolution yield is directly linked to the carboxyl content introduced in the cellulose chains. The periodate oxidation also leads to the decrease of the cellulose degree of polymerization but cellulose DPv still remains sufficiently high in the case of the targeted COOH contents and for textile applications. The possible production of hydroxyl radicals during the periodate oxidation has been investigated by EPR/Spin-trapping. Only trials made with UV radiations showed OH°. Thus, cellulose depolymerization during periodate oxidation made in dark conditions is still not explained. Because the periodate consumption is low during the oxidation, its recycling is a key issue for an industrial application. It has been shown that the oxidation filtrates could be reused several times before total oxidant consumption. The quality of celluloses oxidized with recycled filtrates, especially their dissolving ability, should be checked.
Baldia, Christel M. "Development of a protocol to detect and classify colorants in archaeological textiles and its application to selected prehistoric textiles from Seip Mound in Ohio." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1122567876.
Full textGilmore, Laurie Ann. "Chlorination of synthetic dyes and synthetic brighteners." Thesis, Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/20794.
Full textMichel, Davina. "EVALUATION DU POTENTIEL FIBREUX ET TEXTILE DE LA CANNE A SUCRE (Saccharum officinarum L.)." Phd thesis, Université de Haute Alsace - Mulhouse, 2013. http://tel.archives-ouvertes.fr/tel-01009321.
Full textLanda, Matthieu. "Développement d'un traitement textile alternatif à base de composés époxyde : Compréhension des réactions en jeu." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI052.
Full textThe aim of this thesis is the development of epoxide-based aqueous formulation, which can be used as "easy-care" textile treatment."Easy -care" treatment is applicated to improve wrinkle recovery properties and the dimensionnal stability of textile (cellulosic substrates). This treatment is based on the chemical crosslinking of cellulose microfibers by a crosslinking agent. The formulations developed in this thesis have to substitute the one using formaldehyde derivatives. After a bibliographic study, the epoxide derivatives under acid catalyst (Lewis Acid: zinc tetrafluoroborate) have been selected. Different reactions are possible in the course of the treatment of textile by epoxide in acid media: -Crosslinking of cellulose by etherification, -Acid hydrolysis of epoxide functions, -Cationic polymerization of epoxide derivatives. First, the complex reaction media "epoxide + alcohol + water + acid catalyst" have been investigated by different model reaction studies. The etherification of an alcohol by an epoxide in this media have been highlighted. Then, different epooxid-based aqueous formulation have been developed and experimented as textile treatment at laboratory scale. The formulation are distinguished by the type of epoxide, the quantity of epoxide and the quantity of catalyst. The effect of the treatment on the wrinkle recovery and mechanical properties have been investigated
Boulinguiez, Benoit. "Procédé d'adsorption et régénération électrothermique sur textile de carbone activé - Une solution pour la problématique des COV dans des gaz à fort potentiel énergétique." Phd thesis, Université Rennes 1, 2010. http://tel.archives-ouvertes.fr/tel-00540206.
Full textWilson, Virginia H. "The chemistry of phenolic yellowing of textiles." Thesis, University of Salford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.258352.
Full textRusso, Rachel. "Hanging by a Thread: Enhancing the Forensic Value of Dyed Cotton Trace Evidence through the Application of Novel Techniques in Fiber Discrimination." Honors in the Major Thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/801.
Full textBachelors
Arts and Sciences
Forensic Science
Modh, Haresh A. "Chemical treatment and adhesion in internally reinforced rayon fibers." Ohio : Ohio University, 1988. http://www.ohiolink.edu/etd/view.cgi?ohiou1182867766.
Full textOlszewski, Amy L. "Synthesis, Biological Functionalization, and Integration ofCarbon Nanotubes for Bio-Sensing Textiles." Youngstown State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1369854838.
Full textDominguez, Kimberly. "Leaching of Silver Nanoparticles from Textiles." Ohio University Art and Sciences Honors Theses / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ouashonors155690445799457.
Full textVieira, Valesca Vargas. "Tecidos têxteis: uma temática para o ensino e aprendizagem de Química." Universidade Federal de Santa Maria, 2017. http://repositorio.ufsm.br/handle/1/12735.
Full textIn this study, we used the theme "Textile Fabrics" to contextualize chemical contents, in order to favor the teaching and learning process of Organic Chemistry contents for students of last year of a public school in the city of Santa Maria, RS. In this sense, we seek theoretical references of the theme "Textile Fabrics" to establish the relations with the corresponding chemical contents of the target-public. From this, we developed a proposal to approach these contents in the classroom, which was evaluated through interventions, applied in five stages. The methodology of the Three Pedagogical Moments associated to different teaching strategies such as experimental activities and case studies was used to establish the relationships between the contents of chemistry and the students' daily life from the perspective of the theme. The results of this research were obtained through different data collection instruments such as questionnaires, textual productions, research and presentation of papers, reports, observations and notes made by the researcher during the interventions, which were analyzed according to the Textual Discursive Analysis. Regarding the results, we observe an evolution in the construction of the knowledge and several abilities of high school students, which were verified through Analytical tools. Hence, it can be concluded that the theme "Textile Fabrics", associated to the use of different teaching methodologies, approximated Chemistry to student’ reality favoring the teaching and learning process of Organic Chemistry contents.
Nesta pesquisa, utilizamos a temática “Tecidos Têxteis” para a contextualização de conteúdos químicos, a fim de favorecer o processo de ensino e aprendizagem de conteúdos de Química Orgânica para estudantes da 3ª série do Ensino Médio de um colégio público da cidade de Santa Maria, RS. Para tanto, buscamos referenciais teóricos da temática escolhida “Tecidos Têxteis” para estabelecermos as relações com os conteúdos de química correspondentes da série escolhida. A partir disso, desenvolvemos uma proposta para abordar estes conteúdos em sala de aula, que foi avaliada através de intervenções, as quais foram aplicadas em cinco etapas. Utilizou-se a metodologia dos Três Momentos Pedagógicos aliadas a diferentes estratégias de ensino como as atividades experimentais e estudo de casos, para estabelecer as relações entre os conteúdos de química com o dia a dia dos estudantes sob a perspectiva da temática. Os resultados desta pesquisa foram obtidos por meio de diferentes instrumentos de coleta de dados como: questionários, produções textuais, pesquisa e apresentação de trabalhos, elaboração de relatórios, observações e anotações realizadas pela pesquisadora durante as intervenções, os quais foram analisados segundo a Análise Textual Discursiva. Com relação aos resultados obtidos, observou-se uma evolução na construção do conhecimento e de diversas habilidades dos estudantes do ensino médio, que foi constatada por meio dos instrumentos de análise utilizados. Portanto, pode-se concluir que a temática “Tecidos Têxteis”, associada ao uso de diferentes metodologias de ensino proporcionou uma aproximação da Química com realidade do estudante favorecendo o processo de ensino e aprendizagem de conteúdos de Química Orgânica.
Volkov, Anton. "Ionic and electronic transport in electrochemical and polymer based systems." Doctoral thesis, Linköpings universitet, Fysik och elektroteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-135429.
Full textCarswell, Stewart. "Microanalysis of dyes from textiles." Thesis, Queensland University of Technology, 1991. https://eprints.qut.edu.au/35972/1/35972_Carswell_1991.pdf.
Full textParker, Charlotte Clair. "The (bio)chemistry of cell adhesion in edible plant tissues : its role in texture." Thesis, University of East Anglia, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327534.
Full textRabe, Richard L. "Corona discharge effects on the interfacial adhesion in a sheath-core type composite fiber." Ohio : Ohio University, 1989. http://www.ohiolink.edu/etd/view.cgi?ohiou1172603429.
Full textKaraszi, Zoltan. "Advanced neural network clustering techniques for liquid crystal texture classification." Thesis, Kent State University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1555292.
Full textThis Master Thesis presents a new method of analyzing and classifying liquid crystal textures, using feed-forward neural networks and different clustering techniques. Liquid crystal phases are generally identified by human experts by polarizing optical microscopy observations of textures, based on typical defects, the smoothness or sharpness of domains and the birefringence colors of the films. The thesis aims to establish a novel algorithmic technique for liquid crystal texture analysis and classification. Using image analyzing software, a characterization vector with 22 parameters is extracted for each texture. Advanced clustering algorithms are used to classify textures based on those characteristic parameters. Furthermore, a ranking of the measurements is proposed to refine the accuracy of classification. The proposed methodology will lead to a reliable and simple technique for the physical investigation of liquid crystal materials.
Hedman, Björn. "Dioxin emissions from small-scale combustion of bio-fuel and household waste." Doctoral thesis, Umeå University, Chemistry, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-593.
Full textDenna avhandling behandlar rökgasutsläpp av persistenta organiska föroreningar, framförallt dioxiner, vid förbränning av fasta biobränslen och torrt hushållsavfall i relativt små anläggningar (5-600 kW) utan avancerad rökgasreningsteknik.
Samförbränning av avfall och biobränsle i effektiva mindre biobränslepannor testades som en alternativ strategi till den vanligen förekommande storskaliga hanteringen och förbränningen fast hushållsavfall. Medan storskalig förbränning av avfall ger investeringsmässiga fördelar med rökgasreningsteknik etc. kan små lokala anläggningar ha transportmässiga fördelar och möjligheter till utnyttjande av lokala biobränsletillgångar. Källsorterat, torrt, brännbart hushållsavfall insamlades från hushåll i glesbygd och samförbrändes i brikettform med energigräset rörflen i 150-600 kW biobränslepannor. Endast undantagsvis understeg dioxinemissionerna gällande gränsvärden för avfallsförbränning och nivåerna av väteklorid i rökgas översteg gränsvärdena flerfaldigt. Det bedömdes att någon form av extra rökgasrening är nödvändig för att säkerställa nivågränserna. Dioxiner hittades också i det eldade avfallet, framförallt i textilfraktionen. Dioxinmängderna i rökgaserna var oftast lägre än i det ingående bränslet.
Intermittent pelletseldning gav oväntat höga utsläpp av dioxiner med en emissionsfaktor på 28 ng(WHO-TEQ)/kg. Vedeldning i en modern miljömärkt villapanna gav betydligt lägre utsläpp av dioxiner än eldning i en gammal kombipanna och eldning med full lufttillförsel, som kan jämföras med användning av ackumulatortank, resulterade i upp till 90% minskning av utsläpp av dioxiner jämfört med eldning med reducerat lufttillskott (’pyreldning’). Eldning av plastavfall i en vedpanna gav höga utsläpp av dioxiner.
Okontrollerad förbränning av trädgårdsavfall och hushålls avfall i tunna eller som öppen eld ’bakgårdsbränning’, gav stora variationer i utsläppsnivåer som bara delvis kunde kopplas till avfallsinnehåll. Resultaten visar att denna typ av förbränning kan vara en betydande källa till dioxiner i miljön, och ett emissionsfaktorintervall på 4-72 ng (WHO-TEQ)/kg föreslås för bedömningar av utsläpp från backgårdsbränning av avfall med låga eller måttliga klorhalter.
En sammanfattande slutsats av alla försök är att dioxin utsläpp beror på komplicerade samband mellan bränsleinnehåll och förbränningsbetingelser. Bränslen med mycket höga klorhalter av ger oftast högre utsläpp av dioxiner än bränslen med låga klorhalter medan små skillnader döljs av variationer i förbränningsbetingelser.
This thesis deals with emissions of persistent organic pollutants, primarily dioxins, from the combustion of solid biofuels and dry combustible household waste in relatively small facilities, 5-600 kW, without advanced air pollution controls.
Co-combustion of waste and biofuel in effective small boilers was tested as an alternative to prevailing large-scale management and combustion strategies for handling municipal solid waste. This approach includes no advanced air pollution control systems, but offers two advantages: limiting transport and providing scope to use local biofuel resources. Source-sorted, dry, combustible household waste was collected from households in a sparsely populated area and co-combusted as briquettes together with reed canary-grass in 150-600 kW biofuel boilers. Most trials showed difficulties to meet regulative limits for the emissions of dioxins valid for incineration of MSW and the regulated limits for emissions of hydrochloric acid were exceeded manifold. It was concluded that additional flue-gas cleaning will be needed to ensure that emissions are sufficiently low. Dioxins were also found in the waste, especially in the textile fraction. The mass of dioxins in the flue-gas emissions was generally lower than the mass in the fuel input.
Intermittent combustion of wood pellets in a residential boiler resulted in an unexpectedly high dioxin emissions factor of 28 ng (WHO-TEQ)/kg fuel. Combustion of wood in a modern environmentally certified boiler yielded considerably lower dioxin emissions than combustion in an old boiler, and combustion with a full air supply, i.e. with use of heat storage tank, resulted in up to 90% reductions in dioxin emission factors compared to combustion with reduced air supply. Combustion of plastic waste in a residential wood boiler resulted in high emissions of dioxins.
Tests of uncontrolled combustion of garden and household waste in barrels or open fires, ‘backyard burnings’, resulted in emissions with large variations that could only be partly correlated to the waste constituents. The results imply that this may be an important source of dioxins in the environment and an emission factor range of 4-72 ng (WHO-TEQ)/kg is suggested for estimating emissions from backyard burnings of lightly and moderately chlorine-contaminated waste.
A summarized conclusion from all of the experiments is that predicting emission levels from waste contents is not straightforward (except that fuels with very high chlorine levels will usually result in high levels of dioxins in flue-gas emissions). Moderate differences in chlorine levels will usually be masked by the effect of variations in combustion conditions.
King, Tracy-Anne. "Calcium carbonate crystallisation : the effect of synthetic peptides on crystal growth, morphology and texture." Thesis, University of Salford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244845.
Full textLi, Hualong 1967. "Computer simulation of oxide texture and microstructure formation and their effects on oxidation kinetics." Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=35467.
Full textTwo examples of Ni single crystal and polycrystalline, Zr-2.5%Nb are used to illustrate the proposed computer models. Simplified oxidation mechanisms on Ni and Zr have been proposed.
In the first system, the simulation of oxide texture and oxidation kinetics on the {100} and {111} oriented single crystal Nickel substrate is analyzed. At the nucleation stage the oxide grain orientation is determined by lattice matching between the oxide and the metal substrate. At the stage of oxide grain growth, oxide surface free energy plays an important role. The simulated oxide textures are in good agreement with experimental results. The observed difference in the oxidation kinetics of the two samples is explained by difference in oxide textures formed on the two single crystal substrates. The high percentage of Sigma3 twin boundaries found in the oxide formed on the {111} substrate indicates that the presence of these boundaries significantly improves oxidation resistance.
In the second system where oxidation on Zr-2.5%Nb is simulated and analyzed, lattice matching between the oxide and the metal substrate is used to determine the oxide orientation at the nucleation stage. At the stage of oxide grain growth, oxide orientation is determined by minimizing the compressive stress that is parallel to the metal/oxide interface. Four samples with different substrate orientations have been used in study. The simulated oxide textures and microstructures are in good agreement with experimental results. During the simulation of oxidation kinetics, it is found that oxygen transport through Zr oxide film takes place mainly through two diffusion paths. The first diffusion path is through oxide grain boundaries formed in the bulk alpha-Zr grain region and the second one is through oxide grain boundaries formed at the alpha-Zr grain boundaries and beta-Zr grain region.