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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.
11

PURIFICATION OF BRINE AND PRODUCED WATER USING ACTIVATED CARBON COATED POLYURETHANE FOAM

Ashreet Mishra (7114247) 16 October 2019 (has links)
<p>There is an increased discharge of produced water in the USA, which is causing decrease in the amount of usable water and is being rendered useless by refinery and extraction operations. Produced water that is obtained from these activities is usually not feasible to be used in any form. So, it becomes necessary to get the water to a quality standard, as per the US EPA, which will make this water suitable for both commercial as well as household purposes.</p><p> </p><p>There have been a number of studies on Au, Ag and Carbon Nanotubes solar enabled steam generation with potential applications in water purification, distillation and sterilization of medical equipment. The key challenge with these nanoparticles is cost of production, hence limiting its wide application for clean water production. This work, for the first time, reports on activated carbon enabled steam generation hence addressing the cost limitations of metallic nanoparticles. Activated carbon has high solar absorptivity at various wavelengths of visible light.</p><p> </p>This work uses Activated Carbon coated Polyurethane foam to simultaneously adsorb oil from the produced water and also yield surface vapors under application of solar light to get a clean distillate which can be used in various ways be it commercial or household. The given fabricated system will be an inexpensive and simple method to get clean water. The temporal evolution of the distillate has been measured as well as the temperature characteristics. Experiments were carried out using activated carbon and CNT nanofluids and polyurethane membrane with immobilized activated carbon and CNT. A simulated solar light of 1 KW ~1 Sun was used. The rate of evaporation, temporal and spatial evolution of bulk temperature in the water were monitored automatically and recorded for further data reductions. Parametric studies of the effect of nanoparticle concentration, water quality and salinity were performed. Experimental evidence showed that activated carbon has potential. Previous work reported for the first time that optimal activated carbon concentration for maximum steam generation is 60 % vol. There was a 160 % increase in steam production rate at 60 % concentration of activated carbon when compared with D.I. water.Different atmospheric conditions were varied and the concentration of the sun to see the effects on the production of water. The recovery capacity of the foam was also tested so as to determine the waste oil that can be obtained from the foam and if the foam can be reused without being disposed of. More than 95% oil can be recovered The quality analysis has been performed and is an integral focus of the work as the comparison with the USA EPA (Environmental Protection Agency) will make it more robust and real world ready. The inclusion of Polyurethane foam, which is a major accumulating waste in the environment because of its use in packaging industry, and solar light as the energy source, to drive the distillation process, makes this a very clean and green process to treat produced water.
12

Contribution au développement et à l'industrialisation d'un système non-tissé 3D / Contribution to the development and the indistrialization of a 3D nonwoven system

Njeugna Yotchou, Nicole Suzie 30 November 2009 (has links)
Réalisé dans le cadrr du pôle de compétitivité Véhicule du Futur » de la région ,11k.c Franche Comté_ cc uas_ul de thèse porta sur la hmblcmatsque du remplacement des étoffes complexes textiles utilisées dans les applications d'habillage intérieur automobile. La législation sur les véhicules hors d'usage impose des produits automobiles a 1 $ "), rccyclablcs et t 95' réutilisables dl ici janvier 2015. Alin de rebondie u la problématique posée ainsi qua la législation Europécnnc, des industriels et des acteurs de la recherche de la regain mulhousienne ont lias aillé ensemble dans le cadre du poilez VERTILAP" sur le développement d'un nouveau textile non-tissé 3D. Ce travail de thèse a eu pour objectif de développer le proucde de ! abris ation de ces nouveaux matériaux ainsi que les produits non-tisses 3D obtenus. La démarche de développements procédé produits a consisté Ii faire évoluer le prototype expérimental VERTILAP' au travers de la caractérisation physique et mécanique en compression des produits obtenus. Des méthodes ci dcsj outils de caractérisations adaptés a ces nouveaux produits ont etc mis au point. L'analyse de résultats obtenus s'est appuyée sur les outils statistiques i abn de valider ces résultats. Une étude comparative avec les produits contenant de la mousse polyuréthane (PU) a permis de montrer que ces nouveaux non-tissés 3D pouvaient être utilisés en remplacement des mousses PU. La réalisation de prototypes pour des applications d'habitacle autinnobilu a été faite et a prouvé la faisabilité industrielle d'un tel remplacement. Les résultats de ce travail ont été utilisés pour [élaboration du cahier des charges d'ur prototype semi industriel VERTILAP". / The question of the recycling of the laminated textile fabrics especially in the automotive indusuy represents one of the main requests and challenge of the car manufactures and the OEM's sine 2000. indced, it is nowadays impérative l'or car industry to promote ecological methods of developinent in regard to new consumer sensibility. Rcgarding the Europcan directives 2000 CE53, the automotive products should be at 85% recyclable and at 95% reusable by January 2015. In order to answer this issue, sonie textile industrialists and researchers are working together, through the VERTILAP projet to develop a new material as a 3D nonwoven which will be used to substitute polyuréthane (PU) foam. This work aims to develop the VERTILAP experimental prototype through the physical and mechanical characterizations in compression of thosc new 3D nonwovens. Methods and tools have been canied out to reach Chat goal. Statistical analyses have been used to validate the obtained experimental data. A comparative study between the VERTILAP" products, issued from the VERTILAP" process, and the automotive PU foams bas shows that the new 3D nonwovens can be used to substitute the PU foams. VERTILAP" experimental prototypes such as headrest upholstery and door panel have been developed and have proved the feasibility of the foam exchange. The already obtained results of this work have been taking alto accourt in the spécifications of the new VERTILAP" serai industrial prototype.
13

Application of cellulose nanowhisker and lignin in preparation of rigid polyurethane nanocomposite foams

Li, Yang 18 May 2012 (has links)
Cellulose nanowhisker (CNW) prepared by acid hydrolysis of softwood Kraft pulp was incorporated as nanofiller in rigid polyurethane (PU) foam synthesis. The density, morphology, chemical structure, mechanical properties and thermal behavior of the products were characterized. The nanocomposites exhibited better performance especially at high CNW¡¯s content which was probably due to the high specific strength and aspect ratio of CNW, the hydrogen bonding and crosslinking between CNW and polymer matrix, a higher crosslinking density compared to the control, and the function of CNW as an insulator and mass transfer insulator. Lignin polyol was synthesized through oxypropylation and used for rigid PU foam preparation. The density, morphology, chemical structure, compressive property and thermal behavior of the product were characterized. Lingin-based rigid PU foam showed improved compressive property compared to its commercial counterpart. Ethanol organosolv lignin-based PU showed a slightly stronger compressive property than Kraft lignin-based PU. The enhancement was primarily attributed to the rigid phenolic structure and the high hydroxyl functionality of lignin. Lignin-based PU generated more char than common PUs which was possibly related to the better flame retardant property. This study provided an alternative way to valorize the two most abundant biopolymers and resulted in relatively environmentally benign rigid PU nanocomposite foam.
14

Ultrasonic Concentration of Microorganisms

Mullins, Samuel J 01 January 2012 (has links)
Concentration of microorganisms from a sample volume would increase the limits of detection of samples used for rapid-detection methods. Rapid detection methods are is advantageous for the food industry to rapidly test for bacteria in order release products on a timely basis. Ultrasonic concentration was considered a promising method for manipulation of microorganisms. An ultrasonic chamber consisting of parallel piezoceramic discs with a reticulated polyurethane foam mesh was used to concentrate Saccharomyces cerevisiae yeast and Escherichia coli bacteria. The concentration of yeast was seen to increase by 200% (from 8.0 x 104 cells mL-1 to 2.4 x 105 cells mL-1) while almost zero concentration of bacteria was observed. The poor concentration effect seen with the smaller microorganisms was explained by the volume dependent acoustic radiation force exerted on the particles; the concentration forces are 1,000 times smaller for a 1 μm bacteria cell versus a 10 μm yeast cell.
15

Scalability of cone calorimeter test results for the prediction of full scale fire behavior of polyurethane foam

2014 August 1900 (has links)
The ignition and subsequent burning of polyurethane foam based mattresses poses a significant danger to life and safety in North American homes. The development of fire models which can predict the full scale fire behavior of these mattresses using bench scale data would assist manufacturers and regulators to manage this danger in a cost effective manner. This thesis builds on previous work by the University of Saskatchewan and University of Waterloo fire research groups and focuses on the evaluation of one such scaling model, which was originally developed during the Combustion Behavior of Upholstered Furniture (CBUF) project. The evaluation of the CBUF model conducted in this thesis isolates the heat release rate (HRR) density sub-model and explores the effects of 1) cone calorimeter incident heat flux setting, 2) specimen thickness and 3) ignition location on the predictive capability of the CBUF model. To provide input for the CBUF model cone and furniture calorimeter tests were conducted. Cone calorimeter tests were conducted on foam specimen thicknesses of 2.5, 5.0, 7.5 and 10.0 cm at incident heat flux settings of 25, 35, 50 and 75 kW/m2. Furniture calorimeter tests were conducted on foam specimen thicknesses of 2.5, 5.0, 7.5 and 10.0 cm in both edge and center ignition configuration. Flame area spread rates were measured from infrared video of the furniture calorimeter tests using an automated algorithm. It was found that HRR curves predicted by the CBUF model showed good agreement with experimental results. Experimental results from tests of thinner foams were predicted with greater success than results from thicker foams, and results from edge ignition tests were predicted with greater success than results of center ignition tests. The results of this study indicated that specimen thickness and ignition location need to be considered when selecting an appropriate incident heat flux setting for producing input data for the CBUF model.
16

Elimination of SF6 from transmission system equipment

Cai, Xiaolei January 2013 (has links)
Sulphur hexafluoride gas is the dominant insulation and interruption material in high voltage gas insulated substation. Its usage remains a concern of transmission system operators owing to the global warming potential of the gas. The work carried out in this thesis aims to find the environment-friendly materials that can replace SF6. These candidates are required to have a strong dielectric strength for high voltage busbar insulation and well arc extinguishing capability necessary for high voltage circuit breaker.A range of alternative insulation types including CF3I gas and its mixture, high pressure air and solid insulating foam are considered as substitute of SF6. Theoretical studies on the dimensions of busbars used in substations are carried out for these options. The dimension of the dielectric system and its ampacity of respect system are calculated using heat transfer models considering their boiling point and proper working pressure which is related with the dielectric strength of some gas.On the other hand, SF6 gas circuit breaker is extremely popular on the medium and high voltage power networks owning to its effective arc extinguishing performance. It would be ideal if a substitute material could be found for SF6 as an interruption material. Biodegradable oil PTFE ablation, other gas candidates including N2, CF3I are investigated as possible replacement of SF6 through literature study.The usage of vacuum circuit breaker is eventually capable to operate in high voltage transmission system. Simulations have been carried out with software ATP/EMTP to investigate the influence of different characteristics of vacuum circuit breaker including chopping current level, the dielectric strength of vacuum gap and the opening time. And then the probability of overvoltages when vacuum circuit breakers installed is studied by statistical study in MATLAB.
17

MODEL FOR FLAME-RETARDANT POLYURETHANE FOAM MANUFACTURING

Powell, Cody Smith 30 August 2017 (has links)
No description available.
18

LABORATORY-SCALE EVALUATION OF ARAMID BLEND MATERIAL AS A FIRE BARRIER FOR FLEXIBLE POLYURETHANE FOAM

Shang, Wei 30 May 2016 (has links)
No description available.
19

Development of a Rigid Polyurethane Foam-Reinforced Resilient Masonry Wall System

Forsythe, Carly M. 04 1900 (has links)
<p>Unreinforced masonry (URM) constitutes a large part of current building inventory worldwide, and this type of construction also represents a major seismic risk, especially in developing countries where URM is widely used. During an earthquake, URM walls are unable to dissipate seismic forces without experiencing considerable damage or collapse. Due to their lack of ductility, URM walls fail in a brittle manner, which can leads to damaged face shells becoming falling debris and a major source of hazard. The aim of this study is to investigate the applicability of using polyurethane foams as an inexpensive reinforcement technique for both retrofitting existing and new URM construction.</p> <p>Experimental testing of the reinforced masonry walls showed a large increase in the resiliency of the wall, with an increase in the out-of-plane capacity of up to 34 times over the URM specimen, and with the addition of rope reinforcement an increase in the out-of-plane capacity of up to 90 times the URM specimen was achieved. This system allows walls to experience a considerable amount of deflection before ultimate failure is reached. Within certain limits, the polyurethane foam is able to demonstrate elastic characteristics. By developing foam with higher densities, higher compressive, tensile, flexural and shear strengths can be reached. This type of reinforcement allows for less damage during low seismic events, and through the greater resiliency of the system, walls are able to remain stable and exhibit post-peak strength during a stronger seismic event. In its ultimate limit state, the wall will fail, however collapse is typically prevented – reducing the amount of hazardous debris and saving the lives of the buildings occupants.</p> / Master of Applied Science (MASc)
20

Novel Monomer Design for Next-Generation Step-Growth Polymers

Wolfgang, Josh David 16 July 2021 (has links)
Facile monomer synthesis provided routes towards novel step-growth polymers for emerging applications. Adjustment of reaction conditions enabled green synthetic strategies, and promising scalability studies offered impetus for industrial funding. Engineering thermoplastics, such as linear polyetherimides (PEIs), had carefully targeted molecular weights for analysis of the effect of molecular weight and regiochemistry on the thermomechanical and rheological properties of PEIs. The design of linear, high performance PEIs comprising 3,3'- and 4,4'-bisphenol-A dianhydride (bis-DA) and m-phenylene diamine (mPD) provided an opportunity to elucidate the influence of dianhydride regiochemistry on thermomechanical and rheological properties. This unique pair of regioisomers allowed the tuning of the thermal and rheological properties for high glass transition temperature polyimides for engineering applications. The selection of the dianhydride regioisomer influenced the weight loss profile, entanglement molecular weight, glass transition temperature (Tg), tensile strain-at-break, zero-shear melt viscosity, average hole-size free volume, and the plateau modulus prior to viscous flow during dynamic mechanical analysis (DMA). The 3,3'-PEI composition interestingly exhibited a ~20 °C higher Tg than the corresponding 4,4'-PEI analog. Moreover, melt rheological analysis revealed a two-fold increase in Me for 3,3'-PEI, which pointed to the origin of the differences in mechanical and rheological properties as a function of PEI backbone geometry. The frequently studied 4,4'-PEI exhibited exceptional thermal, mechanical, and rheological properties, yet the 3,3'-PEI regioisomer lacked significant study in the industrial and academic sectors due to its 'inferior' properties, namely poor mechanical properties. Introduction of long-chain branching (LCB) into PEIs provided a unique comparison between a commercially relevant PEI (Ultem® 1000) and a regioisomer infrequently found in the literature. Thermal stability remained consistent for each regioisomer, and Tgs for the 3,3'- and 4,4'-LCB-PEIs agreed well with prior literature. Rheological analysis demonstrated typical shear thinning and low-shear viscosity trends for LCB systems. The targeted molecular weights for the 3,3'-LCB-PEIs were well below the Me cutoff for "high molecular weight," and for this reason the rheological properties demonstrated inconsistent trends. Further study of PEIs led to the incorporation of ionic endgroups. These provided physical crosslinks, which enhanced mechanical and rheological properties of branched PEIs compared to their non-ionic analogs. The Tgs decreased with an increase in branching concentration for the phenyl-terminated PEI, while it remained unchanged for the ionically-endcapped PEIs. The divalent salts demonstrated higher mechanical strength and melt viscosities compared to the monovalent salt and the non-ionic PEIs. Interestingly, the zinc-endcapped PEI series exhibited decreased high-shear viscosities compared to the other PEIs, lending to promising industrial applications for the zinc-endcapped branched and linear PEIs for high temperature applications. Additional engineering thermoplastics in the form of bio-based polyureas exhibited mechanical properties similar to those of non-bio-based polyureas. The isocyanate-free synthetic route incorporated an essential urea degradation mechanism at elevated temperatures to produce isocyanic acid, which then reacted with amines to produce linear polyurea thermoplastics. Urea provided a sustainable and bio-friendly reagent for high molecular weight, isocyanate-free polyureas. Poly(propylene glycol) triamine enabled the long-chain branching of thermoplastic polyureas. Differential scanning calorimetry (DSC) showed no change in Tg for the series; however, melting peaks decreased in intensity as the branching concentration increased, indicating a reduction in crystallinity. Tensile testing eluded to a decrease in ultimate stress values for higher branching concentrations, while melt rheology showed significant differences in melt viscosities. Viscosities increased markedly with an increase in branching concentration, signifying greater entanglement and stronger physical crosslinks for the branched polyureas. Further analysis of possible isocyanate-free routes led to the use of 1,1'-carbonyldiimidazole (CDI) to generate polyureas and polyurethanes. CDI, known in the literature for its use in amidation and functionalization reactions, enabled the production of well-defined and stable polyurethane monomers. The functionalization of butanediol with CDI yielded an electrophilic biscarbamate monomer, bis-carbonylimidazolide (BCI), suitable for further step-growth polymerization in the presence of amines. The reaction of this novel monomer with aliphatic diamines produced thermoplastic polyurethanes with high thermal stability, tunable glass transition temperatures based on incorporation of flexible polyether segments, and creasable thin films. It is envisioned that CDI functionalized diols will afford access to various polymeric backbones without the use of toxic isocyanate-containing strategies. Additionally, non-isocyanate polyurethane (NIPU) foams were produced from BCI monomers without the need of blowing agents, catalysts, or solvents. These materials offered an alternative to existing foaming technology, which typically employed isocyanates. Polyurethanes were foamed through a CO2 thermal decomposition mechanism involving the BCI monomers. We investigated two series of polyurethane foams with a tunable Tg range from ~0 °C to ~110 °C. We found that the incorporation of aromatic amines vastly altered the foam thermomechanical properties, and the resulting foams were closed-cell in nature. / Doctor of Philosophy / Step-growth polymers play a significant role in commercial and industrial applications. On-going work in this field focuses on sustainability, biodegradability, and improved processability. This dissertation encompasses the improvement and innovation of current and novel engineering thermoplastics and foams. The careful purification and step-growth synthetic strategies herein, afforded targeted molecular weights for analysis of linear and long-chain branched (LCB) polyetherimides (PEIs). Further analysis of LCB-PEIs, with monovalent and divalent ionic endgroups, provided an opportunity to study the effect of ionic interactions and physical crosslinks at high temperatures (>300 °C). The long branches improved the melt processability compared to linear analogues at equivalent molecular weights. The challenge to investigate polyurethanes using non-isocyanate methodologies offered an opportunity to apply fundamental small-molecule, organic synthesis to macromolecular science. 1,1'-Carbonyldiimidazole (CDI) provided a platform to generate polymeric chains from industrially relevant monomers. Additional testing serendipitously discovered the generation of CO2 upon thermal degradation of the novel monomers. Harnessing the release of CO2, during the gelation of polyurethanes, provided an isocyanate-, catalyst-, and solvent-free synthetic route towards polyurethane foams that boasts scalability and industrial relevance.

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