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Lindgren, Sanja. "Svenska preppers : Mellan individualism och solidaritet." Thesis, Karlstads universitet, Institutionen för sociala och psykologiska studier (from 2013), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-84298.
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Syftet med denna studie är att få en djupare förståelse för preppers relation till riskerna i dagens samhälle och belysa deras balansgång mellan individualism och solidaritet. I studien har preppers syn på sig själva och deras drivkrafter undersökts. Studien är en kvalitativ undersökning gjord med semistrukturerade intervjuer genomförda via telefon. Analysen av det insamlade materialet bygger på teorier om risksamhället och individen i balansgång mellan individuell frihet och strukturellt tvång; tidigare forskning om just fenomenet prepping används också. Analysen görs utifrån begreppet risksamhälle eftersom prepping handlar just om ett förebyggande arbete mot överhängande risker. Med förförståelsen att prepping rör sig ifrån bilden av en stigmatiserad ensamvarg mot en mer solidarisk samhällsmedborgare har jag använt dikotomin individualism - solidaritet. Resultatet visar att svenska preppers lever med en balansgång mellan individualitet och solidaritet där de vill prioritera den egna säkerheten framför att eventuellt hjälpa andra. Studiens informanter visar att trots en bristande tilltro för myndigheter och upplevd falsk trygghet vill de tillhöra det sociala kollektivet - däremot vill de inte delta i de osäkra systemen som samhället bygger på.
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Vachon, Lauren Marie. "Glow: A Novel." Kent State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=kent1374695902.
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Andersson, Isa. "Hard preppers and soft values." Thesis, Konstfack, Industridesign, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:konstfack:diva-7006.
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Hard preppers and soft Values Survival of the fittest. Who is prepared for a crisis, and who will survive? What type of knowledge is needed to survive in todays society? When I received the folder ”If Crisis or War Comes” from MSB (Swedish Civil Contingencies Agency) I felt a shiver of individualistic expectations to provide and protect yourself in a society where you can’t trust the community. This project is an attempt to challenge the camouflage green violent aesthetics disguised in a highly multifunctional pocketknife. An attempt to challenge who will survive. This is a project about discussing survival from a class and norm perspective thought aesthetics. Discussed in parts as prepping in food and water prepping and defense. All of them in a technique and aesthetics that provokes the topic and challenge the individualism of todays prepping system.
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Keyser, John D. III. "The Effects of Preparer Familiarity and Preparer Affect on Reviewer Decisions." Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case1489679599785707.
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Ehnroth, Malin, and Rössner Carolina Jarvenius. "”Jag är en normal människa” : Drivkrafter och motivation för svenska preppers." Thesis, Stockholms universitet, Sociologiska institutionen, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-156411.
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Uppsatsens syfte är att genom kvalitativa semistrukturerade intervjuer undersöka den ökade popularitet som prepping åtnjuter i Sverige. Med prepping avses i denna studie att medvetet förbereda sig för en större eller mindre samhällskris. Det huvudsakliga teoretiska ramverk som används vid analys av empirin är risksamhället som Ulrich Beck och Anthony Giddens beskriver. Resultatet som framträtt visar att orsaken till prepping i viss mån kan ses som en konsekvens av risksamhället, men handlingen baseras även till stor del på personliga erfarenheter, insikter och värderingar. Det innebär att såväl mikroprocesser kopplade till individer som makroprocesser kopplade till samhället behöver tas i beaktning för att förstå fenomenet. I tidigare forskning beskrivs preppers ofta som personer som förbereder sig för att överleva en total samhällskollaps. I vår studie möter vi istället människor som vill skapa sig ett handlingsutrymme vid en samhällskris. Det handlar alltså inte om att överleva en apokalyps utan om att ha en realistisk förväntan på samhällets krisberedskap och att komplettera den med eget ansvar. I likhet med flertalet andra studier indikerar vårt resultat att prepping kan ses som en livsstil drivet av ett kontrollbehov. Dock uppfattar vi en skillnad mellan våra respondenters svar och andras forskares resultat. De vi intervjuat ger uttryck för att prepping stärker samhällets beredskap, i kontrast till flera andra studier där preppers ses som en grupp som bidrar till samhällets instabilitet och polarisering. Strävan, för de som deltagit i vår studie, är således att stärka samhället, inte att försvaga det. Vidare ser vi att prepping till stor del är drivet av ett intresse och en kunskapstörst. Prepping verkar inte i första hand vara ett svar på risksamhället, utan snarare en reaktion på just-in-time-samhället.
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Lind, Färnstrand Izabel. "How to Prepare for Death." Thesis, Kungl. Konsthögskolan, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kkh:diva-527.
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Abstract of Master essay - 10 HP Izabel Lind Färnstrand Mentor: Emma Kihl Examinator: Sigrid Sandström How to Prepare for Death In this essay I dwell into the failures of our moral senses in relation to the concept of death. How does modern death culture affect our way of life and our ability to take responsibility for the life and death of others? These questions are formed by these current times and affect both my art practice and my everyday life. When facing death within my family it occur- red to me that my and my family’s relationship to death is failing us. I have become frustra- ted with the fear and silence that seems too natural to my surrounding. Not being able to talk about a part of life that is inevitable seems irrational. It became clear when the lack of under- standing and acceptance of death caused relatives an immense suffering. The struggle seemed unnessesary and urged me to try to understand more, based on their deaths. Seeing how very different the experience of dying can be made me wonder what makes a ”good” death possible for some and others not. From there my interest in the topic death culture and fear emerged, and this essay touches on this in a variety of aspects. I use my personal experiences in combina- tion with thoughts of others to talk of layers of these issues through my artistic practice. This personal method is my way of trying to structure a thinking – in a way that I can use and make sense of it – with a varied level of success. I feel it is important to note that I don’t claim to have any answes. This essay is more an attempt to pose questions around human behaviour. Even though many of these ques- tions have been asked over and over again, throughout different times, I believe it is impor- tant to ask them again and again. As long as the Human is part and violently effecting this suffering world. Many of the thoughts in this essay are based on fragments of ideas by Judith Butler, espe- cielly from her book Frames of War: When is Life Grievable? (2009). I also reference Caitlin Doughty’s From Here to Eternity: Traveling the World to Find the Good Death (2017) and and Sogyal Rinpoche The Tibetan Book of Living and Dying (1992). The themes gathered that I try to make use of in this essay and in my artistic practice are purpose, fear, death, health, happiness, narcissim and resposibility.Abstract of Artistic work How to Prepare for Death @ Galleri Mejan, Exercisplan 3, october 2019 Media: Spatial installation with a performance (1 h) Materials: Clay, plaster, metal & red plastic film How to Prepare for Death is a spatial installation in one of the gallery rooms of Galleri Mejan. The work includes the whole space of the area, such as the floor and the walls. You step into an altered reality, where the floor is covered with clay that is cracking increasingly over time and windows that are tinted red so that the air you breath seems red. When you enter your eyes need to adjust and after a while it is rather the outside that seems colored, neon green - the complementary color of red. From the clay there are metal rods sticking out vertically, with plaster sculptures at the end. These sculptures are broken, and resemble body parts with a medical aesthetics. Similar sculptures come out from the walls, like fragile fragments of something that used to be. When you walk around the sculptures the clay crackle under your feet, and crumble into smaller pieces and dust. It is constructed as an ambivalent experience of nothingness, emptiness, ”afterness” and a sanctuary of thoughts. My questions about life and death drive me to investigate how to create spaces for these subjects to feel present, so that we can face our fears.
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Larberg, Ylva. "Deformability of unidirectional prepreg materials." Licentiate thesis, Stockholm : Skolan för teknikvetenskap, Kungliga Tekniska högskolan, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10681.
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Hallander, Per. "Towards defect free forming of multi-stacked composite aerospace components using tailored interlayer properties." Doctoral thesis, KTH, Lättkonstruktioner, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-185694.
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Use of lightweight materials is an important part of reduction of fuel consumption by commercial aircraft. A considerable number of structural aircraft parts are therefore built of thin layers of epoxy pre-impregnated carbon fibres stacked to laminates. Manufacturing these by hand is costly and different methods of automation have therefore been developed. One cost-effective way of manufacturing is Automated Tape Lay-up of flat stacks followed by a Hot Drape Forming operation. A well-known problem in the industry within forming is fibre wrinkling, which can cause a serious strength knock down. The focus of this thesis has therefore been on understanding how and why wrinkles develop during forming of multi-layer stacks and, based on this, investigate different methods for process and material improvements. The work presented initially investigates the dependency between stacking sequence and wrinkle development. It is shown that wrinkle free forming can be obtained by changing the fibre stacking order. In the following investigation it is shown that the wrinkles cannot be entirely eliminated by local stiffening of the critical layers. In a, related study it is shown that different kinds of wrinkles develops during forming; wrinkles may be either due to global buckling of the entire lay-up or local compression of single layers. Global buckling is due to excessive material. Local compression occurs as the material shear during forming. The work presented leads to an understanding of the importance of making the beneficial neighbouring fibre layers interact during forming. One way to connect neighbouring layers is to tailor the interlayer properties. A study is presented that shows how local manipulation of interlayer properties may steer the multi-layered material into a different deformation mechanisms. The manipulation in this thesis is performed using Multi Wall Carbon Nano Tubes, thermoplastic veils or consolidation of thermoplastic toughener particle interlayers.QC 20160425
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Larberg, Ylva. "Forming of stacked unidirectional prepreg materials." Doctoral thesis, KTH, Lättkonstruktioner, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-106269.
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To reduce cost of structural composites, the development of more efficient manufacturing methods is of great interest. An automatic tape layer (ATL) can be used to perform the layup in an efficient way for flat sheets and the second step is by pressure forming the prepreg stack onto a given mould. Sheet forming of thermoset prepreg, also known as hot drape forming, is a promising manufacturing method when combined with automatically stacked laminates. To reach the desired shape, without flaws such as wrinkles and severe fibre angle deviation, knowledge about the forming behaviour of stacked material is important. A simulation of the forming can add to the understanding of mechanisms causing defects and also how to avoid them. A continuum mechanical finite element approach is used to model the forming of stacked unidirectional prepreg. This with the aim of finding mechanisms causing defects, such as out-of-plane wrinkling and in-plane waviness. Data from experimental characterisation of the materials are required for the constitutive material models. An experimental approach is used to investigate the intraply (within the layer) and interply (between the layers) deformation. The intraply deformation behaviour is investigated by a bias extension test, where resistance to deform and fibre rotation are registered. The interlaminar friction characteristics in the prepreg/prepreg interface are retrieved from tests performed with a specially designed rig. Measurements on the bending stiffness of the prepreg, both transverse to and in the fibre direction, are used in the out-of-plane model. Different aerospace-grade thermoset prepreg materials are tested and major differences in behaviour are found. Since epoxy is brittle, the resin is toughened by thermoplastics, for some materials in liquid phase and for others by solid particles. These particles seem to influence both the intraply deformation modes and increase the level of friction between layers. The experimental data from shear, friction and bending tests are used to calibrate the chosen material models. In-plane forming simulations confirm the affect stacking sequence have on the forming behaviour. Full-scale forming simulations on a joggles beam are performed with one of the tested material systems. Two different stacking sequences, with the same amount of fibre in the main directions, are analysed and compared. Both numerical and experimental forming shows that the coupling between layers, due to the interply friction, will affect the forming behaviour and in some cases create wrinkles. Wrinkles can develop both in the plane and out-of-plane, where only the in-plane waviness is present in the performed forming simulations.QC 20121204
KEKS Kostnadseffektiva kompositstrukturer
PRICE Producerbarhet i centrum
XPRES
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Wang, Xuhui. "Heat transfer in composite prepreg tapes." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63880.
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Goodman, Kendall E. "Thermoplastic prepreg manufacture by solution impregnation." Thesis, Virginia Tech, 1990. http://hdl.handle.net/10919/42197.
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Advanced thermoplastic composites are commonly manufactured from "'prepreg" materials, where the reinforcing fibers are preimpregnated with resin. The objectives of this investigation were to identify the critical parameters in impregnation of the fiber tow by a thermoplastic solution, and to produce high quality thermoplastic prepreg. Continuous carbon fibers (AS4 and AU4) were impregnated with a thermoplastic resin solution using a research scale, single tow, drum winding prepreg machine. The parameters varied to control the degree of impregnation of the fiber tow were, weight percent polymer in solution, die size, fiber tow tension, fiber tow velocity, and the use of impregnation pins.
These parameters were varied during the prepregging operation and prepreg samples were evaluated to determine resin content. Viscosity studies were performed on the polymer solutions by means of a Rheometrics Mechanical Spectrometer. Thermogravimetric analyses were performed on the thermoplastic solution and the prepreg. Cross-sectional photomicrographs were obtained to determine the degree of impregnation and the fiber/resin distribution.
Unidirectional laminates were fabricated from the prepreg. Transverse tensile and double cantilivered beam mechanical tests were performed. Fractography photomicrographs were taken. X-Ray photoelectron spectroscopy was used to investigate the possibility of residual solvent in the laminates.
High quality prepreg was manufactured and the critical parameters in the prepregging process were identified and their effect on the prepreg was quantified.
Master of Science
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Martin, Cary Joseph. "Prepreg effects on honeycomb composite manufacturing /." Thesis, Connect to this title online; UW restricted, 1998. http://hdl.handle.net/1773/9861.
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Keilig, Thomas. "Ermittlung des Umformverhaltens von Gewebeprepregs in Abhängigkeit von Verstärkungstyp und Matrixsystem mit Hilfe eines geeigneten rheologischen Materialmodells /." Köln : DLR, Bibliotheks- und Informationswesen, 2006. http://www.gbv.de/dms/bs/toc/515997412.pdf.
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Fisher, Shannon Rae. "Using technology to prepare for future scienTESTS." Diss., A link to full text of this thesis in SOAR, 2006. http://soar.wichita.edu/dspace/handle/10057/565.
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Thesis (M.Ed.)--Wichita State University, College of Education, Dept. of Curriculum and Instruction."July 2006." Title from PDF title page (viewed on April 25, 2007). Includes bibliographic references (leaves 36-39).
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Ali, Monzur. "New synthetic approaches to prepare degradable polymers." Thesis, University College London (University of London), 2008. http://discovery.ucl.ac.uk/1444126/.
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This thesis is concerned with the synthesis of acid labile co-polymers. Two polymer systems were examined (1) polyacetals and (2) poly(ortho esters). As for poly(ortho esters), there is a need for better synthetic methods to prepare these polymers more easily without the need of stringent anhydrous conditions, with more broad structural variation, and in a more cost effective manner. Pendent functionalised polyacetals derived from PEG and tyrosine derived monomer diols have been prepared and their structure activity relationships determined. A smaller size alkyl chain on the tyrosine derived monomer diol increased the rate of degradation of these polyacetal libraries. For poly(ortho esters), a first strategy involved the preparation of novel stable orthoester monomers. The key aspect was to embed the orthoester within the monomer while providing orthogonal polymerisation functionality. This synthetic route attempts to address the synthetic limitations for the preparation of existing poly(ortho esters) and it is believed to be the first such example. The stabile symmetrical bicyclic 2.2.2 orthoester monomer molecule derived from the naturally occurring metabolite phenyl acetic acid was used to prepare the new poly(ortho esters). The bicyclic orthoester 2.2.2 ring arrangement provided the monomer with rigidity, therefore enabling a pure solid monomer to be prepared in three synthetic steps. This approach provided a more efficient polymerisation reaction that requires less stringent polymerisation reaction conditions then existing literature examples for preparing poly(ortho esters). The second broad strategy examined the synthesis of a hydrolytically stable precursor poly (oxetane esters), which underwent a pH triggered rearrangement reaction within the polymer mainchain to prepare orthoester moieties in the polymer mainchain. In conclusion these strategies have provided new synthetic examples of preparing the highly degradable acid labile polymers e.g. poly(ortho esters).
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Main, Patty A. "How Superintendents Prepare School Districts for Change." Ohio University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou14836300290792.
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Björnsson, Andreas. "Automated layup and forming of prepreg laminates." Doctoral thesis, Linköpings universitet, Industriell Produktion, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-137488.
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Composite materials like carbon fiber-reinforced polymers (CFRPs) present highly appealing material properties, as they can combine high strength with low weight. In aerospace applications, these properties help to realize lightweight designs that can reduce fuel consumption. Within the aerospace industry, the use of these types of materials has increased drastically with the introduction of a new generation of commercial aircraft. This increased use of CFRP drives a need to develop more rational manufacturing methods. For aerospace applications, CFRP products are commonly manufactured from a material called prepreg, which consists of carbon fibers impregnated with uncured polymer resin. There are two dominant manufacturing technologies for automated manufacturing using prepreg, automated tape layup and automated fiber placement. These two technologies are not suitable for all types of products, either due to technical limitations or a combination of high investment costs and low productivity. Automation alternatives to the two dominant technologies have been attempted, but have so far had limited impact. Due to the lack of automation alternatives, manual manufacturing methods are commonly employed for the manufacturing of complex-shaped products in low to medium manufacturing volumes. The research presented in this thesis aims to explore how automated manufacturing systems for the manufacturing of complex CFRP products made from prepreg can be designed so that they meet the needs and requirements of the aerospace industry, and are suitable for low to medium production volumes. In order to explore the area, a demonstrator-centered research approach has been employed. A number of demonstrators, in the form of automated manufacturing cells, have been designed and tested with industrial and research partners. The demonstrators have been used to identify key methods and technologies that enable this type of manufacturing, and to analyze some of these methods and technologies in detail. The demonstrators have also been used to map challenges that affect the development of enabling methods and technologies. Automated manufacturing of products with complex shapes can be simplified by dividing the process into two steps. Thin layers of prepreg are laid up on top of each other to form flat laminates that are formed to the desired shape in subsequent forming operations. The key methods and technologies required to automate such a system are methods and technologies for automated prepreg layup, the automated removal of backing paper and the forming of complex shapes. The main challenges are the low structural rigidity and tacky nature of prepreg materials, the extensive quality requirements in the aerospace industry and the need for the systems to handle a wide array of prepreg shapes. The demonstrators show that it is possible to automate the manufacturing of complexshaped products using automated layup and forming of prepreg laminates. Tests using the demonstrators indicate that it is possible to meet the quality requirements that apply to manual manufacturing of similar products.Polymera kolfiberkompositer erbjuder en eftertraktad kombination av låg vikt och högstyrka som kan bidra till lättviktskonstruktioner som t.ex. kan leda till bränslebesparingarför passagerarflygplan. Inom flygindustrin har användningen av denna materialtyp ökatkraftigt med introduktionen av en ny generation flygplan som till mer än hälften består avkompositmaterial. Den ökade användningen av polymera fiberkompositer medför ett ökatbehov av rationella produktionsmetoder. Inom flygindustrin tillverkas ofta polymera kolfiberkompositprodukter av så kallatprepreg-material som består av kolfibrer impregnerade med en plast. Det finns tvåhuvudalternativ för automatisk tillverkning av prepreg-baserade produkter, automatisktejpläggning eller automatisk fiberplacering. De två alternativen har tekniskabegränsningar och är förknippade med mycket höga investeringskostnader vilket gör attdet finns produkter som de inte kan tillverka eller som inte är kostnadseffektiva atttillverka med dessa två metoder. Andra automatiska alternativ har utvecklats, men har intenått någon större industriell implementering. Bristen på automatiseradetillverkningsalternativ leder till att produkter med komplex form, och som tillverkas i småoch medelstora volymer ofta tillverkas manuellt. Forskningen som presenteras i denna avhandling syftar till att undersöka hur automatiskatillverkningsceller för tillverkning av polymera kolfiberkompositprodukter med komplexform kan utformas så att de uppfyller de krav som gäller för tillverkningen av produkterför flygindustrin och är lämpliga för låga och medelhöga tillverkningsvolymer. Endemonstratorcentrerad forskningsmetod har använt för att utforska området och ett flertaldemonstratorer har byggts och testats tillsammans med partners från industrin och andraforskningsorganisationer. Demonstratorerna, som är kompletta tillverkningsceller, haranvänts för att identifiera metoder och utrustning som är nödvändiga att utveckla för attautomatisera denna typ av tillverkning och för att undersöka några metoder och tillhörandeutrustning mer i detalj. Demonstratorerna har också använts för att kartlägga faktorer sompåverkar hur metoder och utrustning utformas. Automatisk tillverkning av produkter med komplex form kan förenklas genom att delaupp tillverkningen i två steg. Först läggs prepreg-ark ihop till ett laminat som formas tillproduktens form i ett efterföljande steg. För att automatisera denna typ av tillverkningbehöver nyckelmetoder och nyckelutrustning för hopläggning av laminat, borttagning avskyddspapper samt formning av laminat till komplexa former utvecklas. Viktiga faktorersom påverkar utformningen av tillverkningscellerna är prepreg-materialens låga styvhetoch klibbiga yta, de höga kvalitetskrav som gäller för tillverkning avflygplanskomponenter samt att systemen måste hantera en stor mängd olikformadeprepreg-ark. Demonstratorerna visar att det är möjligt att automatisera tillverkningen avpolymera kolfiberprodukter med komplex form genom automatisk uppläggning ochformning av plana laminat. Tester med demonstratorerna pekar på att det är möjligt atttillverka produkterna i enlighet med de kvalitetskrav som finns för manuell tillverkningav liknande produkter.
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Hayes, Brian Steven. "Simulation engineering of polymeric prepreg composite systems /." Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/9906.
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Holcomb, Ronald E. "Harambee! working together to prepare African missionaries /." Theological Research Exchange Network (TREN), 1998. http://www.tren.com.
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Graves, Milton L. "Teaching laypeople to prepare a biblical message." Theological Research Exchange Network (TREN), 1999. http://www.tren.com.
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Koski, Timothy R. "The influence of tax preparer psychological commitment and client payment status on the aggressiveness of tax preparer decision making /." free to MU campus, to others for purchase, 1998. http://wwwlib.umi.com/cr/mo/fullcit?p9901253.
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Lundin, Sverker. "Methods to Prepare DNA for Efficient Massive Sequencing." Doctoral thesis, KTH, Genteknologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-105116.
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Massive sequencing has transformed the field of genome biology due to the continuous introduction and evolution of new methods. In recent years, the technologies available to read through genomes have undergone an unprecedented rate of development in terms of cost-reduction. Generating sequence data has essentially ceased to be a bottleneck for analyzing genomes instead to be replaced by limitations in sample preparation and data analysis. In this work, new strategies are presented to increase both the throughput of library generation prior to sequencing, and the informational content of libraries to aid post-sequencing data processing. The protocols developed aim to enable new possibilities for genome research concerning project scale and sequence complexity. The first two papers that underpin this thesis deal with scaling library production by means of automation. Automated library preparation is first described for the 454 sequencing system based on a generic solid-phase polyethylene-glycol precipitation protocol for automated DNA handling. This was one of the first descriptions of automated sample handling for producing next generation sequencing libraries, and substantially improved sample throughput. Building on these results, the use of a double precipitation strategy to replace the manual agarose gel excision step for Illumina sequencing is presented. This protocol considerably improved the scalability of library construction for Illumina sequencing. The third and fourth papers present advanced strategies for library tagging in order to multiplex the information available in each library. First, a dual tagging strategy for massive sequencing is described in which two sets of tags are added to a library to trace back the origins of up to 4992 amplicons using 122 tags. The tagging strategy takes advantage of the previously automated pipeline and was used for the simultaneous sequencing of 3700 amplicons. Following that, an enzymatic protocol was developed to degrade long range PCR-amplicons and forming triple-tagged libraries containing information of sample origin, clonal origin and local positioning for the short-read sequences. Through tagging, this protocol makes it possible to analyze a longer continuous sequence region than would be possible based on the read length of the sequencing system alone. The fifth study investigates commonly used enzymes for constructing libraries for massive sequencing. We analyze restriction enzymes capable of digesting unknown sequences located some distance from their recognition sequence. Some of these enzymes have previously been extensively used for massive nucleic acid analysis. In this first high throughput study of such enzymes, we investigated their restriction specificity in terms of the distance from the recognition site and their sequence dependence. The phenomenon of slippage is characterized and shown to vary significantly between enzymes. The results obtained should favor future protocol development and enzymatic understanding. Through these papers, this work aspire to aid the development of methods for massive sequencing in terms of scale, quality and knowledge; thereby contributing to the general applicability of the new paradigm of sequencing instruments.QC 20121126
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Louis, Bryan Michael. "Gas transport in out-of-autoclave prepreg laminates." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/27484.
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Out-of-autoclave (OOA) pre-impregnated (prepreg) materials are a prospective alternative to traditional autoclave processing, with the potential to reduce processing costs and build structures without size limitations imposed by the autoclave. Gas transport pathways in prepreg laminates play an important role in the removal of entrapped gases and volatiles during processing. Removal of gases by vacuum evacuation is essential in order to produce composite laminates with low final void content. Gas pathways are of particular importance in OOA prepregs where the maximum applied pressure during processing is 1 atm.
In this study, the gas transport of OOA prepreg MTM45-1/CF2426A (epoxy/carbon) laminates is examined. The gas permeability of laminates is carefully measured in the in-plane and through-thickness directions. The study examines the effect of the number of layers, the effect of internal ply terminations, and the effects of heat on laminate gas transport. Supplemental experiments such as laminate compaction, microscopy, and water visualization are conducted to gain additional understanding of laminate gas transport.
The study shows that gas transport is strongly directional for the studied prepreg with significantly higher permeability in-plane than in the through-thickness direction. Counter-intuitively, the permeability of MTM45-1/CF2426A is not found to be greater than autoclave prepreg when compared to carbon/epoxy Toray 3900-2 (plain weave). The physical nature of gas transport pathways in MTM45-1/CF2426A prepreg laminates is found to change with processing state. Debulking was found to decrease in-plane gas transport from its as-laid-up permeability. Laminate heating is found to affect laminate gas transport. In-plane permeability decreased with increasing temperature, while through-thickness permeability increased with increasing temperature. Correlations between gas transport and laminate compaction is also evident. During debulking, laminate compaction is found to correlate to decreasing in-plane permeability. Additionally, laminate compaction is found to relate to the quality of edge breathing.
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Futvoye, Carling E. "Hope for the Best, Prepare for the Worst." Ohio University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1275497655.
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Wang, Tiaoling. "Prepare for Alzheimer’s: Narratives to bind us together." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1522337630772491.
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Elkington, Michael Philip. "The evolution and automation of sheet prepreg layup." Thesis, University of Bristol, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.682486.
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It became evident that Preshearing had simplified the layup process to such an extent that automation had become a more feasible option. Subsequently, a two stage automated process was developed. The preshearing was applied using a custom built press with blank holders around the perimeter to control shearing and prevent wrinkling by applying in-plane tension. A short study on the deformation of prepreg material showed that by heating the prepreg, the deformation could be held in the ply for over an hour after preshearing. Once the plies had been presheared they were passed on to a robotic layup cell based around an industrial six axis robot. Inspired by the way the human laminators used their hands alongside additional hard tools to adapt to different mould features, three bespoke end effectors were developed to tackle different geometric features. A large cylindrical roller was used to consolidate flat and convex regions, while a second ' discus ' shaped roller with a 60° angle at its outer edge was used to tackle tight concave corners. A third end effector was required to tackle tight doubly curved convex corners. A number of hard plastic based tools were trialled, but a hybrid of a silicone wedged tip with an aluminium core provided the right balance of high pressure and conformity. In combination, these three end effectors successfully completed a series of increasingly complex layup tasks. The robotic system was then combined with plies which had been presheared in the press, and an entire sample panel ply was laid-up without any human interaction other than transferring the ply from the press to the mould. Two complete three ply panels were laid-up with the automated system and cured into finished parts. The quality of these layups compared favourably to an additional example made by hand.
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Wolvin, Brad. "How to prepare Australian homeland security emergency planning /." Connect to Electronic Thesis (CONTENTdm), 2009. http://worldcat.org/oclc/444638917/viewonline.
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Gilbert, Eric Nicholas. "Interlayer modified prepreg systems for customized density applications /." Thesis, Connect to this title online; UW restricted, 2002. http://hdl.handle.net/1773/9889.
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Magato, James. "Process Model and Sensor Based Optimization of Polyimide Prepreg Compaction During Composite Cure." University of Dayton / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1533144776251201.
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Fitt, Melynda H. "An Investigation of the Doctoral Dissertation Literature Review: From the Materials We Use to Prepare Students, to the Materials That Students Prepare." DigitalCommons@USU, 2011. https://digitalcommons.usu.edu/etd/1101.
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Practically speaking, a well-conducted review of literature is central to a scholar’s ability to pose pertinent and timely questions within their field. As part of the culminating written assessment of a Ph.D. candidate, the dissertation literature review provides a unique vantage point to explore future scholars’ preparation. In spite of its central role within the research process, research about how future scholars are taught the doctoral competencies necessary to conduct a review of the literature for the dissertation or how the dissertation literature reviews are assessed is limited.
In two separate studies, this research uses the Boote and Beile’s Literature Review Scoring Rubric as a framework to explore the textbooks used in the early stages of doctoral education and the quality of dissertation literature reviews from a field of education research. In the first study, seven of the top selling education research methods textbooks from 2010 were analyzed to determine how well they cover the 12 performance criteria on the rubric. While the results were varied, the majority of textbooks were not adequate in their coverage of the performance criteria identified by Boote and Beile. In short, the materials used to prepare doctoral students may not be equal to conveying critical components of the literature review.
Efforts were then devoted to a replication study of exploring the end results of doctoral training and preparation. In the second study, the Literature Review Scoring Rubric was used to assess the quality of 30 randomly selected dissertation literature reviews from Instructional Technology. The scores of the dissertation literature reviews were also varied. While some dissertation literature reviews in this study were of high quality and scored well, the majority of them were of a lower quality.
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Dubay, Anthony R. "Improving strategies to prevent and prepare for radiological attack." Monterey, California : Naval Postgraduate School, 2010. http://edocs.nps.edu/npspubs/scholarly/theses/2010/Mar/10Mar%5FDubay.pdf.
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Thesis (M.A. in Security Studies (Combating-Terrorism: Policy & Strategy))--Naval Postgraduate School, March 2010.Thesis Advisor(s): Moltz, James Clay. Second Reader: Dahll, Erik J. "March 2010." Description based on title screen as viewed on April 26, 2010. Author(s) subject terms: Radiological Terrorislm, RDD, Dirty Bomb, Public Preparedness, WMD. Includes bibliographical references (p. 87-98). Also available in print.
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Farnand, Kyle Anthony. "Process-induced wrinkling and waviness in prepreg charge-forming." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/56721.
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Carbon-epoxy prepreg C-channels were charge-formed by drape forming onto an aluminum tool. Flange lengths, forming temperatures, ply counts, ply sequences, forming methods, and curing bag types were varied and related to wrinkling, waviness, termination profiles, thickness profiles, microstructures, and mesostructures. Post-cure microscopy evaluation revealed wrinkling in parts formed at room temperature. Greater flange lengths and thinner laminates resulted in greater wrinkling severity. Fibre misalignments were more severe for the ply sequence whose 0° plies were located at the surface, taking the form of full-ply waviness after cure. A wrinkling conversion mechanism was proposed to explain the disappearance of externally visible defects after forming and the appearance of full-ply waviness after cure. The extent of conversion was attributed the curing bag tension and the post-formed wrinkled ply’s location within the charge with respect to the laminate’s outer surface. In all flanges, waviness misalignment angles were equal to or significantly greater than wrinkling misalignment angles. Missing length at the flange termination provided a good approximation of the excess length trapped in the form of wrinkling and full-ply waviness. Additionally, part thickness profiles provided further information on the occurrence of wrinkles. Furthermore, fibre misalignment types and locations were corroborated by non-destructive surface photography. Whether laminates were formed by hand lay-up or by drape forming, waviness gradients were found through the thickness of all 0° plies and attributed to the absence of sufficient intra-ply shear. The differences observed when forming the same ply sequence in alternate orientations may provide insight into the forming compound curvatures. The suggested post-form wrinkle conversion to waviness mechanism provides reason to develop waviness detection capabilities and to improve the understanding of mechanical performance knockdown effects from waviness. This study also proposes that post-forming part surface inspection for externally visible defects can be a critical step in identifying post-cure waviness sites. Defects detected in surface photographs after cure showed promising applicability for locating and identifying types of defects in mould-side surface plies. The occurrence of wrinkling and subsequent full-ply waviness is expected to be reduced if inter-ply slip characteristics are improved, though waviness gradients within individual plies will remain.Applied Science, Faculty of
Materials Engineering, Department of
Graduate
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Flogvall, Erik. "Investigation of consolidation of stacked prepreg during robot forming." Thesis, KTH, Lättkonstruktioner, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-164291.
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The purpose of this thesis was to investigate consolidation performed robotically of stacked epoxy pre-impregnated carbon ber. Consolidation is when the composite is compacted by applying pressure. This removes voids in the composite which increases mechanical properties. The process of consolidation is generally assumed to be viscoelastic. Two tests were made to investigate the viscoelastic properties of the uncured composite material: One relaxation test to investigate how temperature, stacking sequence, strain level and sample size a ects timedependent viscoelastic properties. The second experiment was to study the level of compaction achieved from local consolidation of the composite material, the latter obtained when using an industrial robot. The relaxation test showed that the compression response was decreased with higher temperatures and increased with higher strain levels. Samples with a reduced area showed larger relaxation e ects than unreduced samples. Unidirectionally stacked samples had larger relaxation e ects than samples stacked cross-directionally. The experiment with robotically applied consolidation did not show any measurable compaction at the pressure levels investigated. The lack of compaction is assumed to be caused by shearing of the upper layers due to high tool friction and that the applied pressures were not high enough to noticeably deform the composite material.
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DiLucci, Jasmine. "Tax Return Preparer Liability: A New Approach to Accountability." Scholarship @ Claremont, 2014. http://scholarship.claremont.edu/cmc_theses/880.
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The purpose of this paper is to propose a new theory of civil liability to hold tax return preparers liable to their clients for tax malpractice, applying to understatements, overstatements, and non-optimal tax advice. This paper discusses the tax return preparer’s (TRPs, both signatory and nonsignatory) current liability to the government and to the client, specifically addressing Circular 230, AICPA rules, state boards of accountancy, federal regulations, and malpractice for professionals. It will then go through several case studies to establish current gaps in malpractice law for TRPs, showing how the government is usually favored in court while clients are not. Ultimately, I will explain a general theory of liability to apply nationally for TRPs to increase their accountability to their clients.
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Mehta, Jimit Haresh. "Mild and Convenient Methods to Prepare N-Alkyl Tacrines." Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/77010.
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Alzheimer's Disease (AD) is an irreversible, age-related neurodegenerative disorder which causes cognitive impairment and a wide variety of neuropsychiatric and behavioral disturbances. Acetylcholinesterase inhibitors (AChEI) are the mainstay for the treatment of AD. Acetylcholinesterase (AChE) catalyzes the hydrolysis of acylcholinesters with a relative specificity for acetylcholine (ACh). Observation of a deficiency of cholinergic neurotransmission in AD led to the development of AChEI as the first approved treatment for dementia symptoms. Tacrine (9-amino-1,2,3,4-tetrahydroacridine) is a reversible inhibitor of AChE. It was the first drug approved by the FDA for the treatment of cognitive symptoms of AD.
Tacrine is now rarely prescribed as a drug for the treatment of AD due to its high hepatotoxicity in almost 50% of the patients. However, tacrine derivatives have considerable potential for the palliative treatment of AD. Synthesis of various bivalent tacrines led to the improvement in inhibitory potency and selectivity towards inhibition of AChE. Heptylene-linked bis-tacrine has especially shown immense promise to be an ideal AChEI. Thus dimerization of a lead compound seemed to be an ideal strategy where the compound can bind to both catalytic anionic site (CAS) and peripheral anionic site (PAS) on the AChE enzyme.
However synthesis of N-alkyl derivatives of expanded tacrines like 12-chloro-2-methyl-6,7,8,9,10,11-hexahydrocycloocta[b]quinoline by the standard SNAr methods was unsuccessful and thus alternatives needed to be developed to synthesize N-alkylated and bivalent 12-chloro-2-methyl-6,7,8,9,10,11-hexahydrocycloocta[b]quinoline. Upon exploring the alternatives, N-arylation by Pd-catalysis seemed to be the most mild and convenient alternative over the standard SNAr procedures.Master of Science
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Coleman, Pheobie Latossa. "Executive Management Methods to Prepare Employees for Future Positions." ScholarWorks, 2016. https://scholarworks.waldenu.edu/dissertations/3149.
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Creating successful leaders is one of the challenges that social services organizations are facing. Employees may lack essential managerial skills to become productive leaders, and some managers may lack viable succession planning methods for preparing employees for leadership positions. The purpose of this case study was to explore methods that executive managers use to prepare employees for leadership positions. Path-goal theory and transformational leadership represent the conceptual framework that grounded this study. Semistructured interviews were conducted with 10 executive managers in the social services industry within southwest Georgia with experiences and skills specific to implementing successful succession planning. Company archives of corporate reports, government records, and business and management records were used for triangulation. The data were coded and analyzed using a modified van Kaam method. Participants verified the accuracy of the analysis of their responses through member-checking. The findings revealed 4 emergent themes: organizational management, hiring employees that fit the culture, leadership capabilities, and talent management. A recommendation from the study was that executive managers find methods to prepare employees for leadership positions. These findings may contribute to positive social change by identifying methods to prepare employees for leadership positions, thereby generating organizational sustainability, increasing organization revenue, and creating community economic development.
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Risinger, Cody Ryan. "The Unofficial Preppy Uniform: Yesterday, Today, and Tomorrow." Kent State University Honors College / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ksuhonors1462127014.
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Farhang, Leyla. "Void evolution during processing of out-of-autoclave prepreg laminates." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/50674.
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Out-of-Autoclave (OOA) prepreg processing is a promising candidate for replacement of autoclave (AC) processing, which is the current standard for manufacturing primary structural parts in the aerospace industry. However, its success is dependent on the ability to produce high quality parts with low porosity. This thesis develops an understanding of porosity in this process by studying the evolution of the voids during processing.
Characterization of voids in partially cured laminates is challenging due to the soft nature of the prepreg matrix. A method for preparation of partially cured samples for optical microscopy and porosity measurement is developed and validated by comparison with results from the ASTM standard density method. It is also shown that thickness can be used to estimate porosity for the no-bleed prepreg system used in this study but that the accuracy is lower than microscopy and density methods.
The evolution of voids during different processing cycles and process conditions was studied using the aforementioned optical microscopy on partially cured laminates made of MTM 45-1/5HS carbon/epoxy prepreg. Fiber tow geometry and gas permeability were also measured to determine fibre tow compaction and the gas transport capability throughout the cure process. It is shown that gas transport, fiber bed compaction and resin infiltration govern void evolution during the process.
Porosity is governed by multiple chemical and transport phenomena, among which gas transport through vacuum evacuation plays a crucial role. An understanding of gas transport in OOA prepreg processing is developed by examining the time scales for gas transport by Darcy flow and molecular diffusion and comparing those to experimental gas permeability and porosity data. Darcy flow is shown to be the primary means of gas removal during the process. The study shows that the dominant direction of gas transport is dependent on the aspect ratio of the laminate, the prepreg material and the processing history as both in-plane and through-thickness permeability vary throughout the cure cycle. Based on these observations, a simple debulk map that gives the minimum recommended room temperature debulk time for OOA laminates as a function of in-plane and through-thickness dimensions is presented.Applied Science, Faculty of
Materials Engineering, Department of
Graduate
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Wells, Jeremy. "Behaviour of resin voids in out-of-autoclave prepreg processing." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/55134.
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Resin in prepreg contains small bubbles called resin voids. These voids are isolated from the laminate inter-connected breathing network and cannot be removed by vacuum debulk. Initially these voids contribute negligibly to porosity; however, they may grow and contribute significantly to porosity by vapourization of dissolved volatile species and/or ideal gas expansion particularly in low pressure out-of-autoclave (OOA) processes. Modern advanced prepregs have low volatile content except for moisture due to the hygroscopic property of epoxy. The goal of this study is to investigate the behaviour of resin voids and determine the mechanisms and processing conditions that cause resin void growth. The first part of this study investigates the growth of resin voids in neat resin specimens under controlled temperature, resin pressure and moisture content. Neat resin was vacuum bagged on a glass tool and visually observed in-situ by use of a digital microscope. A criterion that predicts the critical resin pressure below which resin voids can grow due to moisture vapourization was tested for two separate moisture contents and accurately predicts the onset of resin void growth. Additionally, resin voids were observed to contribute significantly to porosity in the very low resin pressure regime due to ideal gas expansion. The results indicate that resin pressure is a critical parameter for mitigating resin void porosity.
The second part of this study investigates resin void growth in laminates by stimulating moisture vapourization and/or ideal gas expansion and comparing them to a porosity free baseline. In order to isolate the effect of resin voids, laminates were fully evacuated before cure. Reduced resin pressure, increased moisture content and increased cure temperature were tested parameters. Laminates were laid up on a glass tool and observed and recorded in-situ. Both surface and bulk porosity were measured for each laminate. In-situ observations and resin pressure correlate well with porosity results based on the resin void growth mechanisms investigated for all test conditions except increased cure temperature. Possible explanations for the discrepancy are discussed. Resin pressure was seen as a critical parameter in porosity management and the concept of a minimum resin pressure is proposed and discussed.Applied Science, Faculty of
Materials Engineering, Department of
Graduate
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Joshua, Calvin N. "A curriculum to prepare pastors for tribal ministry in India /." Link to Dissertations, 2007. http://eprint.cc.andrews.edu/36/.
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Gandikota, Rama G. "Cure kinetics and synthesis of some resins and prepreg systems." Diss., Wichita State University, 2009. http://hdl.handle.net/10057/2561.
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The research reported in this dissertation details the synthesis, characterization and cure kinetics of some resin and prepreg systems. The first chapter gives an introduction to the research presented in this thesis. A summary of epoxy and amine cure reactions that occur in epoxy resins and prepreg systems, the role of catalyst and studies on the cure kinetics with differential scanning calorimetry are presented. The synthesis of various phthalonitrile resins and their cure behavior behavior is also discussed. The second chapter discusses the synthesis of control compounds and physical methods used in later chapters. The third chapter focuses on the cure kinetics of a high performance epoxy prepreg resin system based on DGEBA/TGDDM/DDS using differential scanning calorimetry. Three different sets of experiments were performed in dynamic, isothermal, and combined ramp and soak scanning to follow the cure kinetics in a multi-step cure cycle. The buildup of prepreg resin network structure during the cure cycle has been investigated using Dynamic Mechanical Analysis. Thermal Volatilization Analysis (TVA) and Sub-Ambient Thermal Volatilization Analysis (SATVA) experiments were conducted to fractionalize the condensable products released during curing of the prepreg system. The fourth chapter deals with the cure kinetics of a high performance epoxy prepreg resin system based on TGDDM/DDS with BF3 catalyst with differential scanning calorimentry. As earlier, three different sets of experiments were conducted using dynamic, isothermal and combined ramp and soak scanning to follow the cure kinetics in a multi-step cure cycle. The gel point was measured using dynamic shear rheometry of the prepreg resin in isothermal mode. The fifth nprecursor. The cure profile was investigated on preconditioned resin with muffle furnace under ramp and also combined ramp and soak conditions. The thermal stability of the precured resin was investigated with Thermomechanical analysis. Finally, TVA and SATVA experiments were conducted on uncured resin to characterize volatiles produced during cure.Thesis (Ph.D.)--Wichita State University, College of Liberal Arts and Sciences, Dept. of Chemistry
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Yang, Heechun. "Modeling the processing science of thermoplastic composite tow prepreg materials." Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/17217.
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Mott, Lacroix Kelly, Ashley Hullinger, Mark Apel, William Brandau, and Sharon B. Megdal. "Using Scenario Planning to Prepare for Uncertainty in Rural Watersheds." College of Agriculture, University of Arizona (Tucson, AZ), 2015. http://hdl.handle.net/10150/593579.
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10 pp.Planning for an uncertain future presents many challenges. Thinking systematically and creatively about what is in store through a process called scenario planning can help illuminate options for action and improve decision-making. This guide focuses on a process for developing scenarios to help communities and watershed groups explore what might happen in the years to come, make more informed decisions today, and build a watershed management process. The systematic approach to scenario planning described here is based on the lessons learned through a yearlong scenario planning process in the Upper Gila Watershed in southeastern Arizona and Water Resource Research Center’s (WRRC) research on scenario planning.
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Melén, Anton. "Case Studies: How to prepare for a complex research process." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-32947.
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Wray, Brenda Caroline. "Development of Novel Methods to Prepare Nitrogen and Oxygen Heterocycles." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1306329847.
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Mohr, John Darrell. "Technology-mediated distance education used to prepare special education personnel." Thesis, University of North Texas, 2004. https://digital.library.unt.edu/ark:/67531/metadc4544/.
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This study examined how technology-mediated distance education is used in special education courses in teacher preparation programs. The data are based on a 30-item survey administered to members of the Teacher Education Division of the Council for Exceptional Children, who identified themselves as serving in an instructional capacity within institutions of higher education. Technology-mediated instruction was characterized in terms course delivery methods and program attributes. An analysis of instructional design processes revealed that most instructors are largely autonomous and do not rely on a team-based approach. Most make use of course-design and management software. Training is linked to course strategy and evaluation, while experience is associated with implementation. Respondents emphasized communication and student feedback. While both users and non-users of distance education technology foresaw the increased use for course delivery in the future, a notable percentage (13%) of current users indicated a desire to discontinue use.
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Champeau, Mathilde. "Supercritical CO2 Assisted Impregnation to prepare Drug-eluting Polymer Implants." Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0205/document.
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Le procédé d’imprégnation par voie CO2 supercritique est une solution prometteuse pour préparer des implants polymère à libération contrôlée de médicaments.Ce travail a permis de comprendre l’influence des paramètres gouvernant ce procédé et de préciser dans quelle mesure ce procédé peut être utilisé pour préparer des implants polymères chargés en médicament. Pour ce faire, nous avons combiné les informations obtenues grâce aux techniques classiques de caractérisation de polymères et à un dispositif que nous avons développé basé sur la micro-spectroscopie FTIR haute pression in situ.Dans cette étude, des fils de suture de PLLA, PP and PET ont été imprégné avec deux anti-inflammatoires (aspirine et kétoprofène).Tout d’abord, l’évolution du comportement des systèmes binaires médicament/CO2 (solubilité et spéciation) et polymère/CO2 (quantité de CO2 adsorbé, gonflement de la matrice, évolution de la microstructure et des propriétés de tension du polymère) a été déterminé en fonction de la pression et de la température. Ensuite, le procédé d’imprégnation a été étudié. L’influence des conditions expérimentales sur le taux d’imprégnation a été déterminée et expliquée par la quantité de CO2 adsorbé, le gonflement de la matrice, la solubilité du médicament, l’évolution de la microstructure du polymère et aussi l’affinité médicament/polymère. La matrice de PLLA a pu être plus largement imprégnée (jusqu’à 32%) que celles de PP et PET (5% max). Enfin, l’influence des conditions d’imprégnation et de dépressurisation sur le relargage a été démontrée sur le système PLLA/Kétoprofène, la durée de relargage variant de 3jours à 3moisThe scCO2 impregnation process is a promising alternative to other manufacturing process to prepare drug-eluting polymer implants.This work enabled to rationalize the influence of the key parameters governing this process and to determine in which extent this process can be used to prepare drug-eluting implants. We have combined the information obtained with traditional polymer characterization techniques and a newly characterization set-up we have developed that is based on in situ FTIR micro-spectroscopy. We have worked on the impregnation of sutures made of PLLA, PP and PET with two anti-inflammatory drugs namely ketoprofen and aspirin.Firstly, the thermodynamic behaviors of the systems drug/CO2 (solubility and speciation of the drug) and polymer/CO2 (CO2 sorption, polymer swelling, evolution of the polymer microstructure and of the tensile properties) were studied as a function of pressure and temperature. Then, the scCO2 impregnation process was investigated. The impact of the operational conditions on the drug loading (contact time, pressure, temperature and depressurization conditions) was explored and accounted regarding to the CO2 sorption, the2swelling, the drug solubility as well as the changes in the polymer microstructure with the experimental conditions and the presence of the drug. The drug/polymer affinity was also explored. The tensile properties of the impregnated fibers were also evaluated. PLLA was more impregnated (up to 32%) than PP and PET (up to 5%) in the investigated conditions. Finally, we have shown that the drug release can be tuned from 3 days to 3 months by varying the impregnation and depressurization conditions on the system PLLA/Ketoprofen
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Friesen, Ingrid E. "You prepare a table before me responding to God's grace /." Online full text .pdf document, available to Fuller patrons only, 2001. http://www.tren.com.
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Chea, Ming Kai. "Investigating In-plane Shear Behaviour of Uncured Unidirectional Prepreg Tapes." Thesis, KTH, Lättkonstruktioner, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-262011.
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Steering of prepreg tows in an automated fibre placement (AFP) process allows geodesic layup trajectory over a doubly-curved surface, as well as the potential to improve the efficiency of composite structures by tailoring their stiffness. However, defects (such as out-of-plane buckling and tow pull off) are commonly generated when the steering radius exceeds a critical limit, which impact the mechanical properties of the finished product. The in- and out-of-plane material properties of the prepreg tows have been shown to significantly influence the quality of the layup. In this thesis, in-plane shear behaviour of uncured IMA-M21 unidirectional (UD) prepreg was characterised using an off-axis tensile test to derive material parameters for process models to predict steering limits and defects. Test parameters, such as shear strain rates and temperatures, that were investigated were consistent to the actual AFP process. The results demonstrates the expected strain-rate and temperature dependencies related to the resins viscoelastic behaviour. Subsequently, a novel micro-mechanical finite element (FE) simulation of a 3-dimensional UD prepreg unit cell in pure shear was conducted to gain qualitative insights into the complex rheological behaviour at play. It effectively demonstrates how fibre friction, resin viscosity and shear strain rates influence the load transfer between fibres and melt, as well as the movement of fibres during the shearing process. These were reflected in the shear stress-strain curves generated in the simulation and elastic micro-buckling observed in the fibre elements. The results pave a way for future development of a robust material model for predicting the critical process parameters to achieve quality layups from AFP steering process.Automated Fibre Placement (AFP) är en automatiserad metod för tillverkning av högpresterande fiberkompositkomponenter inom främst flygindustrin. AFP gör det möjligt att styra fiberupplägget genom att följa den geodetiska vägen ¨over dubbelkrökta ytor. Detta ger effektiva kompositstrukturer där fibrerna tillåts ligga i precis de rätta, skräddarsydda riktningarna för bästa möjliga mekaniska prestanda. Det finns dock begränsningar, speciellt när det gäller kritiska styrradier där defekter som fiberbuckling och fiber-släpp lätt uppstår. Dessa defekter påverkar den färdiga produktens mekaniska egenskaper. Skjuvegenskaperna i planet hos de ohärdade prepregens fiberbuntar och buckling ut ur planet har visat sig ha stor inverkan på kvalitén hos fiberuppläggen. I denna avhandling undersöks skjuvegenskaperna hos ohärdad IMA-M21 enkelriktad (UD) prepreg med hjälp av ett icke-axiellt dragprov. Syftet ¨ar att ta fram materialdata för simulering av fiberuppläggets begränsningar, för att kunna bestämma hur AFPn bör styras. Modellerna ska ¨aven prediktera de defekter som uppstår. Testparametrar så som skjuvhastigheter och temperaturer undersöks för att efterlikna den verkliga AFP-processen. Resultaten fångar det förväntade skjuvhastighet- och temperaturberoende som ges av matrisens viskoelastiska egenskaper. Baserat på dessa modeller tas en nya mikromekanisk modell fram som implementerad i Finita Element (FE) ger kvalitativ inblick i den komplexa reologin som inverkar. Modellen påvisar tydligt hur fiberfriktion, matrisens viskositet- och skjuvhastighet påverkar kraftföreningen mellan fiber och matris, så väl som förflyttningen av fibrer under skjuvprocessen. Resultaten banar väg för framtida utveckling av robusta materialmodeller för att kunna prediktera kritiska parametrar för att åstadkomma högkvalitativa
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Kerr, Mariann. "Teaching Strategies to Prepare Prelicensure Nursing Students to Teach-back." Diss., NSUWorks, 2016. https://nsuworks.nova.edu/hpd_con_stuetd/28.
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Background: Prelicensure nursing programs prepare generalists with essential knowledge, skills, and attitudes to practice in complex health care environments. Nurse educators determine which teaching strategies will best prepare the nurse generalist. Purpose: The purpose of this study was to determine the effectiveness of a teaching plan that combined the strategies of pretest/posttest, classroom activities, and a problem-based learning activity: a clinical immersion experience. The skill of "teach-back" was taught and evaluated. Theoretical framework: Two theories guided the teaching plan for this research. Adult learning theory (Knowles, 1975, 1980, 2012) addressed how and why adults learn, and social cognitive theory (Bandura, 1977, 1986) described teaching strategies that assisted the adult learner to gain knowledge. Methods: A non-experimental design divided consenting participants were into intervention (n = 21) and control groups (n = 11). The Health Literacy Knowledge and Experience Survey (Cormier, 2006) was used to pretest/posttest for attainment of knowledge related to teach-back. The Communication Assessment Tool (Makoul, Krupat, & Chang, 2007) was used by standardized patients to evaluate the participants' ability to perform a teach-back. Results: The results of this study provided evidence that posttest scores improved for both intervention and control groups (n = 32). Twenty-seven participants performed a teach-back with evaluation. The results did not indicate a significant difference between groups in performing the skill of teach-back. Conclusion: There was little difference in posttest scores for groups and participants' ability to perform a teach-back, indicating that both groups gained knowledge and skill from the teaching strategies.