Дисертації з теми "PVBV"
Щоб переглянути інші типи публікацій з цієї теми, перейдіть за посиланням: PVBV.
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-36 дисертацій для дослідження на тему "PVBV".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте дисертації для різних дисциплін та оформлюйте правильно вашу бібліографію.
1
Morais, Douglas. "Avaliação da tensão superficial do PVB e da PA-6." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/3/3133/tde-07112008-093303/.
Повний текст джерелаАнотація:
No laboratório de Análise, Processamento e Reologia de Materiais Poliméricos da Escola Politécnica da USP tem sido estudadas blendas de Poliamida-6 (PA-6) e filme de poli(vinil butiral) (PVB), como uma alternativa para reciclagem do filme de PVB oriundo do processo de separação dos componentes do vidro laminado pós-consumo. As propriedades mecânicas de uma blenda polimérica dependem da sua morfologia e, por sua vez, a morfologia depende das propriedades reológicas e da tensão interfacial entre os polímeros formadores da blenda, que para o caso de blendas envolvendo filme de PVB podem mudar em função da concentração de plastificante presente na composição do filme. Apesar da importância do seu conhecimento, a tensão interfacial entre PA-6 e filme de PVB não é conhecida. O presente trabalho teve como objetivo avaliar a tensão superficial do filme de PVB e da PA-6. O método utilizado foi o da gota pendente. Também estudou-se a influência da adição de plastificante na tensão superficial do filme de PVB. Os resultados mostraram que a tensão superficial dos polímeros estudados decresce com o aumento da temperatura (temperatura variando entre 240 e 260ºC). Em particular, para o filme de PVB a entropia de superfície ( (d/dT) ) apresentou um valor acima dos normalmente encontrados para polímeros fundidos. Este comportamento foi atribuído à estabilidade térmica do filme. O filme de PVB utilizado nos ensaios de tensão superficial foi caracterizado por Espectroscopia no Infravermelho (FTIR), Espectroscopia no Ultravioleta/Visível (UV-VIS), Espectroscopia Eletrônica para Análise Química (ESCA) e Análise Termogravimétrica (TG). Os resultados obtidos comprovaram que há mudanças na estrutura do PVB durante sua exposição a temperaturas elevadas, por longo período de tempo (condições do ensaio de tensão superficial). Foi observado, primeiramente, a evaporação do plastificante, seguida por perda de grupos polares (-OH, C=O e C-O-C) presentes na estrutura do PVB. A tensão superficial da Poliamida-6 foi determinada para temperaturas de 250 e 260ºC. Os resultados mostraram que a PA-6 manteve-se estável durante os ensaios.In the Rheology and Polymer Processing Laboratory of Escola Politécnica of the University of São Paulo, Polyamide-6 / poly(vinyl butiral) film blends have been studied as an alternative for the recycling of post-consumption laminated glasses. The mechanical properties of these blends were studied and explained in light of their morphology. The morphology of polymer blends strongly depends on the rheological behavior of the blend and on the interfacial tension between the polymers forming the blend. In the case of Poliamide-6 (PA-6)/poly(vinyl butiral) (PVB) film blends, the interfacial tension depends on the plasticizer concentration present in PVB film. However, to our knowledge neither the PA-6/PVB film interfacial tension nor the surface tension of PVB film at temperatures above softening temperatures have been evaluated. In this work, the surface tension of poly(vinyl butyral) and polyamide was evaluated using the pendant drop method. Also it was tried to evaluate the surface tension of PVB film as a function of plasticizer content. The surface tension values obtained were in the same range as the ones obtained for other molten polymers: the surface tension decreases with increasing temperature (for temperatures ranging from 240 to 260°C). However, the value of PVB film surface entropy ((d/dT) where is the surface tension and T is the temperature) was much larger than values reported for other molten polymers. This result was attributed to thermal stability of PVB film during the surface tension measurement. The drops of PVB film after surface tension analysis were examined for any change in their functional groups using infrared spectroscopy (FITIR), ultraviolet-visible spectroscopy (UV/VIS), electron spectroscopy for chemical analysis (XPS/ESCA) and thermogravimetric analysis (TG). The results showed that changes in the chemical structure of PVB film occur during surface tension measurement. First, the plasticizer within the PVB film evaporates and, then, the PVB suffers reduction of polar units and creation of C=C bonds. The surface tension of PA-6 was evaluated for temperatures of 250 and 260°C. The PA-6 remained stable during tests.
2
Galdino, Debora Godoy. "Análise acústica não linear dos padrões visuais de dinâmica vocal (PVDV) de homens adultos." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/82/82131/tde-29112013-095147/.
Повний текст джерелаАнотація:
O objetivo deste trabalho foi descrever a dinâmica não linear das vozes de homens adultos sem queixas vocais por meio dos padrões visuais de dinâmica vocal (PVDV). Participaram 77 homens falantes nativos do português brasileiro com idades entre 20 a 40 anos (média 30 anos ± 5,54 anos). Para análise não linear foi adotado o método de reconstrução do espaço de fase e gerado um gráfico bidimensional a partir de uma rotina desenvolvida no MatLab® 10.0. Este gráfico foi analisado qualitativamente pela técnica dos PVDV que considera três aspectos da configuração: número de laços das órbitas, regularidade e espaçamento dos traçados. Cada aspecto foi classificado em uma escala de 4 a 0, da melhor para a pior configuração. Todos os indivíduos apresentaram qualidade de voz adaptada na variabilidade normal de acordo com os resultados da avaliação perceptivo-auditiva pelo protocolo CAPE-V e da análise acústica pelo programa MDVP-Kay Pentax. A avaliação do protocolo CAPE-V apresentou média de 18,07 mm (± 4,14 mm), no grau geral da vogal /a/. Na avaliação acústica as médias foram de 125,44 Hz (± 20,78 Hz) para F0; 0,85% (± 0,64%) para jitter; 3,23% (± 1,75%) para shimmer e 0,13 (± 0,02) para NHR. Os resultados da dinâmica não linear por meio dos PVDV se mostrou com número de laços em grau 4 (85,71% com média de 3,84 ± 0,40), regularidade em grau 3 e 4 (ambos com 40,26% e média de 3,12 ± 0,95) e espaçamento em grau 3 (58,44% e média de 2,95 ± 0,76). Concluiu-se que os PVDV da vogal /a/ de homens adultos brasileiros com vozes adaptadas dentro da variabilidade normal apresentou padrão visual caracterizado em sua maioria por presença de 4 ou mais laços, traçados regulares ou com discretas irregularidades e com espaçamento entre as linhas de médio a pequeno.This work intended to describe the nonlinear dynamics of voices from adult men without vocal complaints using a qualitative analysis of Vocal Dynamics Visual Pattern (VDVP). 77 men speakers of Brazilian Portuguese, aged between 20-40 years old (mean 30 years ± 5.54 years), participated. For the nonlinear analysis a Phase Space Reconstruction was adopted and a two-dimensional graphic was generated from a routine developed on MatLab® 10.0. This graphic was qualitatively analyzed by a VDVP technique, which considers three aspects of the configuration: orbits loop numbers, regularity and spacing of the traces. Each aspect was classified in a scale ranging from 4 to 0, from the better to the worst configuration. All subjects had voice quality adapted on normal variability according to the results of the perceptual evaluation protocol for CAPE-V and acoustic analysis by the program MDVP Kay-Pentax. The perceptual analysis using CAPE-V protocol showed an average of 18,07 mm (± 4,14 mm), in Overall Severity of vowel /a/. On the acoustic analysis, means of 125,44 Hz (± 20,78 Hz) to F0; 0,85% (± 0,64%) for jitter; 3,23% (± 1,75%) for shimmer and 0,13 (± 0,02) for NHR using MDVP program. The results of nonlinear dynamics through PVDV proved with the number of loops in degree 4 (85.71% with a mean of 3.84 ± 0.40), regularity in degree 3 and 4 (both with 40.26% and mean of 3.12 ± 0.95) and degree 3 in spacing (58.44% and mean 2.95 ± 0.76). It was concluded that PVDV of the vowel /a/ of adult males Brazilians with adapted voices on the normal variability presented visual pattern characterized mostly by the presence of 4 or more loops, regular tracings or with discrete irregularities and spacing between lines of medium to small.
3
Santos, Miguel Bernardino dos. "Algumas contribuições ao Projeto Para Viver de Bem com os Bichos (PVBB) enfoque: fauna sinantrópica." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/10/10134/tde-23032011-154120/.
Повний текст джерелаАнотація:
O projeto educativo Para Viver de Bem com os Bichos PVBB tem sido aplicado junto a instituições de ensino da Cidade de São Paulo - SP, Brasil e consta de dois módulos: Posse Responsável e Fauna Sinantrópica. O presente estudo foi delineado para analisar a dinâmica deste processo educativo, avaliando o papel dos sujeitos no repasse das informações sobre animais sinantrópicos. Houve o acompanhamento do curso de formação oferecido pelo Centro de Controle de Zoonoses em São Paulo-SP-Brasil, com avaliação dos conteúdos apreendidos pelos multiplicadores e da ação de duas multiplicadoras, professores, alunos e responsáveis em uma unidade de ensino. Foram utilizados questionários de auto-preenchimento, com questões abertas para a análise de conteúdos que após a categorização foram submetidos ao teste de McNemar e concordância kappa. Questões semi-abertas foram utilizadas para caracterizar os grupos sociais homogêneos. A análise de correspondência foi utilizada para estabelecer relações entre respostas e grupos sociais homogêneos. Constatou-se que a implementação do PVBB contribui para a melhoria do grau de conhecimento dos multiplicadores sobre fauna sinantrópica; entretanto a participação no curso do CCZ. A participação dos multiplicadores no curso não foi suficiente para instrumentá-los para o repasse de conteúdos do projeto e de informações técnicas em sua unidade de ensino. Os professores contribuíram no repasse de informações aos alunos dentro das possibilidades que lhes foram oferecidas. Não houve impacto significativo no repasse de informações dos alunos aos seus responsáveis entretanto é interessante observar que, quando da sua existência, este repasse variou nos grupos sociais homogêneos detectados e na condição de haver oportunidade de diálogo em casa.A utilização da agregação das famílias dos sujeitos, em grupos sociais homogêneos, permitiu avaliar a inserção social dos mesmos.A análise feita com a utilização dos grupos sociais homogêneos permitiu avaliar tendências de associações diferenciadas entre os GSH e as respostas citadas pelos responsáveis.The educative project How to live well with the animals has been applied to educational institutions in the city of São Paulo SP Brazil and has two modules: responsible pets ownership and the other synanthropic fauna. The current study was written to analyze the dynamics of the educational process, evaluating this research subjects in the role of re-passing the information about synanthropic animals. The course offered by the Municipal Center of Zoonosis Control (CCZ), in São Paulo (SP), is offered to multiplier teachers. This course was accompanied and the taught topics to the multipliers were evaluated by applying a self-filling-questionnaire, before and after the course. The teaching action on this taught topics, was accompanied in the school where two multipliers worked. The taught topics were evaluated in the same way again, but considering the teachers, who had received information from the two multipliers, and the children, who studied in the school, and these childrens parents or tutors. The self-filling-questionnaire was composed of free open answers in order to evaluate the taught topics. The topics were statistically studied by McNemar and Kappa concordance test. Another questionnaire with part-closed questions was used to study the social insertion which was studied by the Social Homogeneous Group (SHG) methodology. The correspondence analysis ANACOR-was used to study relations among the SHG and the taught points. The study indicated that PVBB project increases multipliers information about synanthropic animal, but the multiplier could not act on re-passing the information and technical taught to the teachers in the school. The participation of the multipliers in the course was not sufficient for preparing them to act in this way. According to the possibilities the teachers could re-pass part of the topics with their students. There was no sigificative impact on the students action of re-passing the information to their parents or tutors, but it was interesting to observe that the re-passing actions was different according to the homogeneous social group, and the possibility of dialogue between the child and the familiars. The use of SHG methodology could evaluate the social insertion and different association tendencies between the SHG and the answers written by the parents and tutors.
4
Farias, Italo Fernando. "Estudo da influência da radiação gama nas propriedades mecânicas e térmicas de \"elastômeros termoplásticos\" blendas de poli (cloreto de vinila) com poli (vinil butiral)." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-11102018-083413/.
Повний текст джерелаАнотація:
A vasta gama de sistemas poliméricos classificados como blendas tem sido alvo crescente no meio acadêmico e científico. A possibilidade de obtenção de propriedades combinadas e múltiplas, associada a incorporações de blendas poliméricas, enriquece a condição de pesquisa abrindo assim uma extensa área de atuação. Neste trabalho foi proposto o estudo de mistura de composto de poli (cloreto de vinila) plastificado com resíduo de poli (vinil butiral), proveniente de laminados para produção de para-brisas da indústria automotiva, bem como a investigação do efeito da irradiação gama com dose absorvida de 25 kGy, 30 kGy e 40 kGy, controlado com uso de dosímetro de PMMA e taxa de dose equivalente de 0-10 kGy.h-1. Foram analisadas variações das propriedades mecânicas e térmicas das amostras antes e após exposição à radiação gama. As formulações foram constituídas em diferentes concentrações: composto de PVC-C, resíduo de PVB-R, PVC-C/PVB-R 90/10, PVC-C/PVB-R 50/50 e PVC-R/PVB-R 50/50. O composto de poli (cloreto de vinila) foi formulado e aditivado, apresentando comportamento de um elastômero termoplástico, produto flexível. Foram incorporadas aparas moídas de poli (vinil butiral), provenientes de laminados para produção de para-brisas. Ambos os materiais foram incorporados em extrusora granuladora tipo rosca simples e submetidos ao processo de calandragem para efetivação da mistura e formação de mantas plásticas. As mantas foram irradiadas em um reator multipropósito de 60Co e caracterizadas para verificação das propriedades mecânicas e térmicas. Para tanto, as blendas após exposição à radiação gama apresentaram propriedades mecânicas e térmicas intermediarias as propriedades dos seus componentes, mostrando-se um material resistente e de baixo custo. Por meio da microscopia eletrônica de varredura obteve uma redução nos vasos interfaciais mostrando um aumento na capacidade de percolação do PVB na matriz de PVC, favorecendo suas propriedades físicas.The wide range of polymer systems classified as blends has been increasingly targeted in the academic and scientific milieu. The possibility of obtaining multiple and combined properties, combined with the incorporation of polymer blends, enriches the research condition, thus opening up an extensive area of performance. In this work the study of the poly (vinyl butyral) plasticized polyvinyl chloride mixture from laminates for automotive windshield production was investigated, as well as the investigation of the effect of gamma irradiation with absorbed dose of 25 kGy, 30 kGy and 40 kGy, controlled with use of PMMA dosimeter and equivalent dose rate of 0-10 kGy.h-1. Variations of the mechanical and thermal properties of the samples were analyzed before and after exposure to gamma radiation. The formulations were constituted in different concentrations: PVC-C compound, PVB-R residue, PVC-C/PVB-R 90/10, PVC-C/PVB-R 50/50 and PVC-R/PVB-R 50/50. The polyvinyl chloride compound was formulated and added, exhibiting the behavior of a thermoplastic elastomer, a flexible product. Poly (vinyl butyral) ground chips were produced from laminates for the production of windshields. Both materials were incorporated in a single-thread granulator extruder and submitted to the calendering process to effect the mixing and formation of plastic blankets. The blankets were irradiated in a 60Co multipurpose reactor and characterized for verification of mechanical and thermal properties. In order to do so, the blends after exposure to gamma radiation presented mechanical properties and intermediate thermal properties of their components, showing a resistant material and low cost. By means of the scanning electron microscopy it obtained a reduction in the interfacial vessels showing an increase in the percolation capacity of the PVB in the PVC matrix, favoring its physical properties.
5
Yang, Ping. "Particle Vaporization Velocimetry and Quantitative Soot Concentration Measurement in Sooty Flows." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19843.
Повний текст джерелаАнотація:
Soot is a combustion generated pollutant that is both a direct risk to human health and a contributing source to global environmental change. Soot can also be a controlling factor in heat transfer inside combustion systems. Thus there is a growing interest in being able to measure soot and understand its production in practical, turbulent combustion environments. Therefore, the specific objectives of this research work were: (1) developing a way to measure velocity of sooty regions that is compatible with existing methods for measuring temporally and spatially resolved soot concentration fields and (2) using these methods to make quantitative measurements of soot in an unsteady, turbulent-like combustor. The Particle Vaporization Velocimetry (PVV) technique was developed and is compatible with Laser Induced Incandescence (LII), a soot concentration measurement approach. PVV is a flow tagging approach, where a high intensity laser (~2-3 J/cm2) is used to vaporize a small region in the soot field. This approach was demonstrated to produce a long lasting and easily readable flow tag that allows for velocity measurements over a wide range of velocities. LII proved to be the best method for detection the motion of the tag after a fixed delay. PVV and LII were used to measure velocity and two-dimensional soot concentration fields in an acoustically excited burner. In addition, images of soot luminosity were obtained. Both laminar and transitional acetylene diffusion flames were studied. The results reveal that strong acoustic forcing can significantly reduce total flame soot, as well as maximum soot concentrations, while simultaneously increasing the average soot temperature. The influence of acoustically generated vortices on soot formation was studied, and soot and products mixture mostly likely dominant high soot concentration regions. Eventually, these mixtures will be propagated downstream and oxidized as a diffusion flame.
6
Wingren, Magdalena. "Windscreen study using a free moving headform : An investigation of windscreen behaviour when subjected to headform impact." Thesis, Högskolan i Skövde, Institutionen för teknik och samhälle, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-5382.
Повний текст джерелаАнотація:
Pedestrian protection performance becomes more and more in focus for the car manufactures and systems to reduce injury risk are under development. A wider understanding of both the present and the future windscreen performance in free moving headform testing is needed to optimize these systems. The purpose of this thesis was therefore to learn and understand windscreen behaviour when subjected to head impact and to gain knowledge of CAE status for head impact in windscreens from a pedestrian point of view. A literature review concluded that there are different ways to model a windscreen. It was found that the computer material models for laminated windscreen glass were not capable of fully representing the behaviour of this material under all impact conditions, particularly the non-linear behaviour after fracture or failure. Experimental testing on three different windscreen models, with a free moving headform in a horizontal impactor, has been performed. Test set up was according to Euro NCAP pedestrian testing protocol and three different windscreen angles were tested. The parameter investigated was curvature and HIC and deformation depth on the windscreen were used as evaluation tools. Deformation was measured with a laser positioned behind the windscreen at impact. Film analysis and integration of headform accelerations were used as comparison. The testing concludes that different curvature alone will not have a big influence on HIC and deformation. Keywords: PVB laminated windscreen, pedestrian, impact, free moving headform
7
Krauss, Vivian Alexandra. "Aplicação do sistema de ligantes PVB-PEG-AE e modelagem da etapa de extração na MPI de alumina." Florianópolis, SC, 2005. http://repositorio.ufsc.br/handle/123456789/102594.
Повний текст джерелаАнотація:
Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia Mecânica.Made available in DSpace on 2013-07-16T01:22:26Z (GMT). No. of bitstreams: 0
Um sistema de ligantes contendo alumina para moldagem por injeção foi testado com diferentes teores de carga sólida. O sistema de ligantes contendo três componentes, ácido esteárico (AE), polietilenoglicol (PEG) e polivinilbutiral (PVB) foi utilizado numa proporção de 2:1 de PEG:PVB e 25:1 de Al2O3:AE. As misturas foram caracterizadas por meio de reometria capilar. A mistura com melhores características para moldagem por injeção foi escolhida para o estudo de remoção de ligantes.
8
Llamas-Hernandez, Mayra. "Modélisation dynamique et caractérisation de films hybrides magnétiques de nanoparticules de polyvinylbutyral/oxyde de fer (PVB/Fe2O3) pour microactionneurs." Thesis, Bourgogne Franche-Comté, 2019. http://www.theses.fr/2019UBFCD034.
Повний текст джерелаАнотація:
L'objectif global du projet de recherche est de modéliser et de contrôler le comportement dynamique d'un matériel hybride magnétique développé à l'Universidad Autonoma de Nuevo Leon (UANL, Mexique) et d'explorer le potentiel en tant que microactionneur. Le matériel magnétique se compose de polyvinylbutyral comme phase polymerique (PVB) et une phase dispersée de nanoparticules d'oxyde de fer (Fe2O3). Ce matériel présente une déformation en réponse à un champ magnétique externe appliquéThe overall objective of this research project is to model and control the dynamic behavior of a magnetic hybrid material developed at Universidad Autónoma de Nuevo León (UANL, Mexico) and to explore its potential as microactuator. The hybrid material consists of a polymer matrix film of polyvinyl butyral (PVB) with iron oxide nanoparticles (Fe2O3). The main motivation for this research project is to propose a physical model of the dynamic behavior of a magnetic hybrid film (Fe2O3/PVB) when it is submitted to an external magnetic field
9
Challarapu, Muralidhar. "Slurry based coatings on silicon based ceramics." Cleveland, Ohio : Cleveland State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=csu1276196736.
Повний текст джерелаАнотація:
Thesis (M.S.)--Cleveland State University, 2009.Abstract. Title from PDF t.p. (viewed on June 25, 2010). Includes bibliographical references (p. 37-38). Available online via the OhioLINK ETD Center and also available in print.
10
Cormier, Ryan. "N-Acyl Ciprofloxacins: Synthesis, Antibacterial Activity and Effects on Molecular Loading of Poly(vinyl benzoate) Nanoparticles." Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4018.
Повний текст джерелаАнотація:
Bacterial infections are becoming progressively more difficult to treat due to antibiotic resistance and the decreasing rate at which new antibiotics are brought to market. The Turos laboratory has attempted to tackle this problem for the last 15 years with the discovery of N-thiolated β-lactams leading to the design of polyacrylate nanoparticles to deliver these and other drugs. Chapter 1 discusses many reported instances of utilizing different types of polymeric nanoparticles to deliver antibiotics. Poly(lactic-co-glycolic acid) (PLGA), poly(alkyl cyanoacrylate) (PACA), poly(styrene-co-butylacrylate), and chitosan are the main polymers used to make nanoparticles. Chapter 2 describes the synthesis, antibacterial activity, and mechanism of action of N-acyl ciprofloxacins, which have demonstrated in vitro bioactivity against Staphyloccocus aureus, methicillin-resistant Staphylococcus aureus, Bacillus anthracis, Enterococcus faecalis, Bartonella, and E. coli. Antimicrobial activity was found to diminish with increasingly lipophilic acyl groups of the derivatives. The N-acyl ciprofloxacins were found to utilize the same mechanism of action as the parent drug, ciprofloxacin, however, several exhibited lower mutation frequencies. Chapter 3 discusses the use of the N-acyl ciprofloxacins as probes for experimentation on the poly(vinyl benzoate) nanoparticles. These compounds were incorporated into poly(vinyl benzoate) nanoparticles, also designed in the Turos laboratory, to determine the effects of the lipophilic acyl groups on drug loading and drug release. N-acyl ciprofloxacins with higher lipophilicities (predicted logP values) experienced higher drug loading than the less lipophilic counterparts. However, the nanoparticles were unable to release large amounts of entrapped drug. N-acyl ciprofloxacins with increased hydrophilicity were found to either not be incorporated at all, or in incredibly small amounts. Drug release studies of these drugs indicate that possible the hydrophobic compounds that were associated with the nanoparticles were done so via adsorption onto the surface resulting in a burst release of drug. The work is concluded in Chapter 4, followed by experimental procedures and spectral data in Chapters 5 and 6.
11
Akter, Shaheda T., and Mohammad Khani. "Characterisation of laminated glass for structural applications." Thesis, Linnéuniversitetet, Institutionen för bygg- och energiteknik (BE), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-26275.
Повний текст джерелаАнотація:
Laminated glass (LG) consists of two or more glass layers bonded by an elasto-polymeric layer, the most commonly used being PVB (Polyvinyl Butyral). LG has improved safety properties compared with single layer glass because the interlayer prevents large sharp pieces from spreading when the glass is broken by impact. Even if one of the layers breaks, the other layer(s) still contribute in carrying the load. Through proper understanding of the interaction between the interlayer and the glass LG could be used in engineering as a load bearing material to a larger extent. This study aims at gaining a deeper knowledge of the behaviour of laminated glass by experimental investigations and by numerical model simulation. To pursue the proposed study, three point bending test with simple support conditions were performed for single layer glass and laminated glass units with three different types of interlayer materials. Corresponding finite element numerical models were created in the software ABAQUS to fit the model with experiment to obtain the bending stiffness and shear stiffness of the interlayer material. The PVB tested showed viscos-elastic material properties, whereas other two interlayer materials, Solutia DG 41 and Sentry Glass, showed linear elastic properties. PVB is the least stiff interlayer material among the three types. Solutia DG 41 and Sentry Glass have similar stiffness, about 13 to 15 times stiffer than the PVB. The behaviour of laminated glass lies in general between the two limits of a layered glass unit with no interaction and a monolithic unit of the same total thickness, depending on the stiffness of the interlayer material. Failure tests of the specimens were also carried out. The obtained strength of glass from four specimens is 80 MPa to 92 MPa with a variation of about 15%. The number of more performed experiments would have better outcome for strength of glass. The bending stiffness of the laminated glass as estimated with the numerical model fitted well with the experimental results with an error of about 2%. Hence the experimentally and numerically obtained results show a good correlation and are thought be possible to use in future larger scale modelling.
12
Lindmark, Axel. "Pandemier och populism : En komparativ idéanalys om hur populistiska partiers syn på covid-19 pandemins restriktioner har ändrats." Thesis, Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-55396.
Повний текст джерелаАнотація:
The covid-19 pandemic has hit every part of life hard. From visiting the supermarket to halting world trade. One of the most obvious effects of the pandemic has been the political one. All across the world political parties have been competing for power during these unusual times. This paper will analyze whether populistic parties around Europe have changed their views on the covid-19 pandemic restrictions. In order to analyze this a comparative idea analysis will be used in order to compare and analyze political parties views on this subject. In order to conduct this analysis the studie compare four different populistic parties around europé. These parties are as followed, AFD and Die Linke in germany, PVV in the Netherlands followed by Syriza in Greece. The study will be using material from the four different parties to conduct the analysis and compare the material. The analysis shows that only one out of four parties has had a change in their views on the pandemic restrictions. This study is an important contribution the field of populism. It will grant a unique opportunity to study such a unique time of our the world that the covid-19 pandemis really is.
13
Dandolov, Philip. "Europeanization as a cause of Euroscepticism : comparing the outlooks of parties in Eastern and Western Europe : Bulgaria (Ataka), Romania (PRM), the Netherlands (PVV) and Germany (die Republikaner)." Thesis, University of Bath, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.636527.
Повний текст джерелаАнотація:
This thesis examines party-based Euroscepticism across four different national contexts in the period 2011-3 by bringing into focus right-wing populist parties. Understanding Europeanization as a label for the impact of engagement with the EU and its practical and normative influences on statecraft, policy-making, and the wider society, the thesis looks into the Europeanization of narratives of national identity, minority rights issues, immigration and citizenship. It discusses the way in which the impact of engagement with the EU is perceived as well as the nature of the arguments made against the EU’s involvement in associated policy processes. There has been a recent upsurge in Euroscepticism due to a combination of economic and political factors, on both the popular and party level in EU countries, as well as the increased blurring of the boundaries between mainstream and fringe Eurosceptics. Hence, it is important to analyze the precise reasons behind this phenomenon. The discussion focuses on “soft Euroscepticism” – the thesis is generally not interested in pondering the generic arguments against a country’s membership in supranational entities or shedding light on those parties who oppose the underlying values on which the EU project rests. The thesis therefore probes the attitudes of parties that – with the recent and partial exception of the PVV in the Netherlands – tend to emphasize relatively specific issue-areas as sources of concerns. This work is primarily based on qualitative methods - 32 elite interviews with nationalist-populist politicians including key figures such as party leaders (Rolf Schlierer, Gheorghe Funar), European Parliament representatives (Barry Madlener) and members of the National Parliament as well as of the general party councils (Ventsislav Lakov) in addition to detailed analysis of policy documentation and books authored by party representatives – and highlights and deconstructs these parties’ grievances attributable to nationalistically-oriented concerns. It includes a detailed literature review that clarifies the EU’s impacts and country-specific historical and contemporary differences in the four domains affected by “Europeanization” (Chapters 1-3) and then in Chapters 4-6 uses original empirical data to compare the attitudes of the four parties – Ataka, PRM, REP, and PVV – with regard to the issues already introduced. The thesis utilizes theoretical approaches drawn from several disciplines ranging from political science to sociology, though it mostly confines itself to those pertaining to core group or minority/ethno-regionalist nationalist mobilization, ethnic vs. civic nationalisms in Eastern vs. Western Europe, as well as the different role played by EU conditionality in relation to the political landscape on the two sides of the continent. Extrapolating from this body of research, it develops hypotheses and projections regarding the expected disconnect in viewpoints between Eastern and Western parties. The study finds that attitudes towards “Europeanized” issues areas diverge greatly and do not necessarily correlate with the extent to which EU membership as a whole is opposed by the party. In line with previous research findings, the EU’s capacity to create a super-order nationalism that could challenge conventional readings of patriotism is generally not conceptualized as a significant threat. However, the interviews did reveal that pre-existing transcendent identities – like Latin identity in the case of Romania or the Slavic one in Bulgaria - – are perceived as threatened or as being tacitly degraded due to assumed cultural biases within the EU. At the same time, the reduced salience of such identities among the members of the Western populist parties does not make them more sympathetic to Pan-Europeanism. EU effects on immigration are predictably rated as manifestly detrimental by the West European parties, because they distrust the professionalism of EU agencies and networks, dislike the Eastern Europeans’ increasing involvement in making higher-level decisions and perceive the EU as more liberally inclined than the national government in this realm (with the latter two points especially applicable to the PVV). However, it was interesting that the East Europeans also expressed some disquiet due to the EU’s supposed culpability in encouraging emigration of their own citizens and the presumed unwillingness of the EU organs to offer them the necessary financial means for combating immigration into Bulgaria across the Turkish border. However, contrary to theoretical expectations, the study suggests that there are no hard and fast rules when it comes to the populist party’s proclivity to regard the EU as an ally of “minority lobbies”, with the PVV (the most Eurosceptic party) assessing the relevancy of this aspect as minor, while it is gauged to be of fundamental importance by Ataka (less Eurosceptic than the PVV). Among CEE populists, the thesis shows how “privileged minorities” like Hungarians and Turks are viewed with alarm due to supposedly making use of the EU level in order to advance their secessionist ambitions (Hungarians in Romania) or improve their socio-economic prospects at the expense of the majority (Turks in ethnically mixed regions of Bulgaria). In short, the thesis establishes that there is still a strong dividing line between Eastern and Western populist parties in relation to the assessments made with regard to the impact of the EU on European identity, migration issues and majority-minority dynamics.
14
Ghosh, Arijit. "Degradation of polymer/substrate interfaces - an attenuated total reflection Fourier transform infrared spectroscopy approach." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1291130563.
Повний текст джерела
15
Mollá, Romano Sergio. "Application of Nanofibres in Polymer Composite Membranes for Direct Methanol Fuel Cells." Doctoral thesis, Universitat Politècnica de València, 2015. http://hdl.handle.net/10251/58611.
Повний текст джерелаАнотація:
[EN] Direct methanol fuel cells are feasible devices for efficient electrochemical power generation if some issues can be solved regarding both electrodes and membranes. The research carried out in this Ph.D. thesis has particularly focused on the concerns associated with the membranes.
Nafion is the most standard fuel cell membrane material due to its high proton conductivity and exceptional chemical and mechanical stability. However, it suffers from a considerably high methanol permeability and a limited operating temperature (< 80 ºC). The first aspect was addressed with the use of PVA nanofibres and the second one replacing Nafion with SPEEK-based polymers.
Composite membranes of Nafion with PVA nanofibres, surface functionalised with sulfonic acid groups, exhibited lower methanol permeabilities due to the intrinsic barrier property of PVA, although proton conductivity was also affected as a result of the non-conducting behaviour of the bulk PVA phase. Remarkably, the nanofibres provided strong mechanical reinforcement which enabled the preparation of low thickness membranes (< 20 micrometres) with reduced ohmic losses, thus counteracting their lower proton conductivities.
SPEEK-based membranes were examined for DMFC operation within the intermediate temperature range of 80-140 ºC, in which sluggish electrochemical reactions at the electrodes are accelerated and proton conductivity activated.
SPEEK was blended and crosslinked with PVA and PVB polymers for avoiding its dissolution in hot water conditions. SPEEK-PVA compositions showed practical proton conductivities and SPEEK-PVB blends presented very low methanol permeabilities.
Nanocomposite membranes composed of SPEEK-30%PVB nanofibres embedded in a SPEEK-35%PVA matrix were prepared and characterised. A nanocomposite membrane crosslinked at 120 ºC revealed promising results for DMFCs operating at intermediate temperatures.
Electrospinning is concluded to be a suitable technique for obtaining polymer nanofibre mats intended for advanced composite membranes with improved characteristics and fuel cell performances.[ES] Las pilas de combustible de metanol directo son dispositivos factibles para la generación electroquímica eficiente de energía eléctrica si se pueden solucionar algunas cuestiones relacionadas tanto con los electrodos como las membranas. La investigación llevada a cabo en esta tesis doctoral se ha centrado particularmente en los problemas asociados con las membranas. Nafion es el material de membrana más común para pilas de combustible debido a su alta conductividad protónica y excepcional estabilidad química y mecánica. Sin embargo, padece una considerablemente alta permeabilidad al metanol y una limitada temperatura de operación (< 80 ºC). El primer aspecto se abordó con el uso de nanofibras de PVA y el segundo reemplazando Nafion con polímeros basados en SPEEK. Membranas compuestas de Nafion con nanofibras de PVA, funcionalizadas en su superficie con grupos ácidos sulfónicos, exhibieron menores permeabilidades al metanol debido a la propiedad barrera intrínseca del PVA, aunque la conductividad protónica también se vio afectada como resultado del comportamiento global no conductor de la fase de PVA. Remarcablemente, las nanofibras proporcionaron un refuerzo mecánico fuerte que permitió la preparación de membranas de bajo espesor (< 20 micrómetros) con unas pérdidas óhmicas reducidas, así contrarrestando sus menores conductividades protónicas. Se examinaron membranas basadas en SPEEK para la operación de pilas de combustible de metanol directo dentro del rango intermedio de temperaturas entre 80-140 ºC, en el que las lentas reacciones electroquímicas en los electrodos se aceleran y la conductividad protónica se activa. El SPEEK se combinó y entrecruzó con los polímeros de PVA y PVB para evitar su disolución en condiciones de agua caliente. Las composiciones de SPEEK-PVA mostraron conductividades protónicas funcionales y las mezclas de SPEEK-PVB presentaron permeabilidades al metanol muy bajas. Se prepararon y caracterizaron membranas nanocompuestas constituidas por nanofibras de SPEEK-30%PVB embebidas en una matriz de SPEEK-35%PVA. Una membrana nanocompuesta entrecruzada a 120 ºC reveló resultados prometedores para pilas de combustible de metanol directo operando a temperaturas intermedias. Se puede concluir que la electrohilatura es una técnica apropiada para la obtención de mallas de nanofibras poliméricas destinadas a membranas compuestas avanzadas con características y rendimientos en pilas de combustible mejorados.
[CAT] Les piles de combustible de metanol directe són dispositius factibles per a la generació electroquímica eficient d'energia elèctrica si es poden solucionar algunes qüestions relacionades tant amb els elèctrodes com les membranes. La investigació duta a terme en esta tesi doctoral s'ha centrat particularment en els problemes associats amb les membranes. Nafion és el material de membrana més comú per a piles de combustible a causa de la seua alta conductivitat protònica i excepcional estabilitat química i mecànica. No obstant això, patix una considerablement alta permeabilitat al metanol i una limitada temperatura d'operació (< 80 ºC). El primer aspecte es va abordar amb l'ús de nanofibres de PVA i el segon reemplaçant Nafion amb polímers basats en SPEEK. Membranes compostes de Nafion amb nanofibres de PVA, funcionalizades en la seua superfície amb grups àcids sulfónics, van exhibir menors permeabilitats al metanol a causa de la propietat barrera intrínseca del PVA, encara que la conductivitat protònica també es va veure afectada com resultat del comportament global no conductor de la fase de PVA. Remarcablement, les nanofibres van proporcionar un reforç mecànic fort que va permetre la preparació de membranes de baixa grossària (< 20 micròmetres) amb unes pèrdues òhmiques reduïdes, així contrarestant les seues menors conductivitats protòniques. Es van examinar membranes basades en SPEEK per a l'operació de piles de combustible de metanol directe dins del rang intermedi de temperatures entre 80-140 ºC, en el que les lentes reaccions electroquímiques en els elèctrodes s'acceleren i la conductivitat protònica s'activa. El SPEEK es va combinar i va entrecreuar amb els polímers de PVA i PVB per a evitar la seua dissolució en condicions d'aigua calenta. Les composicions de SPEEK-PVA van mostrar conductivitats protòniques funcionals i les mescles de SPEEK-PVB van presentar permeabilitats al metanol molt baixes. Es van preparar i caracteritzar membranes nanocompostes constituïdes per nanofibres de SPEEK-30%PVB embegudes en una matriu de SPEEK-35%PVA. Una membrana nanocomposta entrecreuada a 120 ºC va revelar resultats prometedors per a piles de combustible de metanol directe operand a temperatures intermèdies. Es pot concloure que l'electrofilatura és una tècnica apropiada per a l'obtenció de malles de nanofibres polimériques destinades a membranes compostes avançades amb característiques i rendiments en piles de combustible millorats.
Mollá Romano, S. (2015). Application of Nanofibres in Polymer Composite Membranes for Direct Methanol Fuel Cells [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/58611
TESIS
Premiado
16
Botz, Martin [Verfasser], Geralt [Akademischer Betreuer] Siebert, Geralt [Gutachter] Siebert, and Jens [Gutachter] Schneider. "Beitrag zur versuchstechnischen und numerischen Beschreibung von Verbundglas mit PVB-Zwischenschicht im intakten und gebrochenen Zustand / Martin Botz ; Gutachter: Geralt Siebert, Jens Schneider ; Akademischer Betreuer: Geralt Siebert ; Universität der Bundeswehr München, Fakultät für Bauingenieurwesen und Umweltwissenschaften." Neubiberg : Universitätsbibliothek der Universität der Bundeswehr München, 2020. http://d-nb.info/1222619679/34.
Повний текст джерела
17
Botz, Martin [Verfasser], Geralt [Akademischer Betreuer] Siebert, Geralt Gutachter] Siebert, and Jens [Gutachter] [Schneider. "Beitrag zur versuchstechnischen und numerischen Beschreibung von Verbundglas mit PVB-Zwischenschicht im intakten und gebrochenen Zustand / Martin Botz ; Gutachter: Geralt Siebert, Jens Schneider ; Akademischer Betreuer: Geralt Siebert ; Universität der Bundeswehr München, Fakultät für Bauingenieurwesen und Umweltwissenschaften." Neubiberg : Universitätsbibliothek der Universität der Bundeswehr München, 2020. http://nbn-resolving.de/urn:nbn:de:bvb:706-6846.
Повний текст джерела
18
MARCHISIO, SILVIA. "Composite Materials reinforced by Carbon Nanotubes." Doctoral thesis, Politecnico di Torino, 2013. http://hdl.handle.net/11583/2506164.
Повний текст джерелаАнотація:
The work of this Ph.D. thesis has been realised in the field of a promising and largely studied technological material: the carbon nanotubes (CNTs). Since 1991 a large number of attempts have been conducted, trying to exploit the outstanding potential of this carbonaceous material, in order to improve the properties of several matrices. The most important application is the production of polymer matrices composites (PMCs), but in last decades an increasing number of metal matrix ones (MMCs) have been presented and recently also ceramic matrix (CMCs) applications have been attempted. Despite massive efforts focused on CNTs-composites, the potential of employing this reinforcement materials has not yet been fully exploited. This lack is substantially due to the difficulties associated with the dispersion of entangled carbon nanotubes during processing and poor interfacial interaction between CNTs and matrix materials. Because of these reasons the very first aspect of this work has been the study of the dispersion state of nanotubes. The aim of the experiments was not only to obtain a good dispersion and distribution of the CNTs, but also to evaluate their dispersion grade. Indeed, due to their nanosize and to their carbonaceous nature, few simple experimental techniques result suitable for this purpose. The second part of the work consisted in the application of the carbon nanotubes to the production of new materials for technological applications, with improved mechanical properties. Three composite materials with different matrices have been designed, developed and produced: a polymer matrix composite, a ceramic matrix and a metal matrix one. For PMCs a polyvinyl butyral matrix has been used and the composites were obtained by a deeply studied technique: the tape casting technology. The same approach was also used in the case of CMCs: tape casted silicon carbide matrix composites reinforced by carbon nanotubes have been produced. Finally a third matrix has been experimented: MMCs were investigated starting from pure aluminium powders. For Al matrix composites a particular technique was used: the sintering was obtained starting from a powder metallurgy approach and exploiting electric current and pressure (Electric Current Assisted Sintering approach). For all the three different composite materials, after the development of the production route and the preparation of several specimens, a characterization step followed. The materials were characterized in terms of physical properties, morphology and microstructure, and mechanical behaviour.
19
Andersson, Simon. "Point-of-care beta-hydroxybutyrate determination for the management of diabetic ketoacidosis based on flexible laser-induced graphene electrode system." Thesis, Linköpings universitet, Sensor- och aktuatorsystem, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-179116.
Повний текст джерелаАнотація:
Diabetic ketoacidosis (DKA) is a life-threatening condition that can appear in patients with diabetes. High ketones in the blood lead to acidity of the blood. For DKA diagnosis and management, ketones such as hydroxybutyrate (HB) can be used to quantify the severity of the disease. The fabrication of electrochemical biosensors for the detection of HB is attractive since their capability to deliver fast response, high sensitivity, good selectivity and potential for miniaturisation. In this thesis, an integrated electrode system was prepared for the detection of HB. Laser-induced graphene (LIG) with a 3D porous structure was used as the flexible platform. Poly (toluidine blue O) (PTB) was electro-deposited on LIG (PTB/LIG) under the optimised conduction (pH of 9.7 and from 0.4 to an upper cyclic potential of 0.8 V). The single PTB/LIG working electrode demonstrated excellent performance towards the detection of NADH with a linear range of 6.7 M to 3 mM using chronoamperometry, high sensitivity of detecting NADH and excellent anti-fouling ability (94 % response current retained after 1500 s). Further integration of the 3-electrode system realised the static amperometric detection of NADH over the range of 78 M to 10 mM. Based on the excellent performance of PTB/LIG to NADH sensing, hydroxybutyrate dehydrogenase was immobilised via encapsulation with chitosan and polyvinyl butyral (PVB) which was used for HB biosensing over the linear range of 0.5 M to 1 mM with NAD+ dissolved in solution. In addition, the co-immobilisation of NAD+ and HBD on PTB/LIG was conducted by optimisation of enzyme and NAD+ amount per electrode, which shows excellent reproducibility and satisfactory HB biosensing performance. Further experiments to improve the long-term stability of the enzyme electrode is expected in the future. The proposed integrated electrode system also possesses the potential to extend to a multichannel sensor array for the detection of multiple biomarkers (e.g. pH and glucose) for diagnosis and management of DKA.
20
Sabharwal, Pallavi. "Molecular Insights into the Structure and Function of Pepper Vein Banding Virus Encoded Proteins and Endocytic Uptake Pathway of Virus-like Particles into Mammalian Cells." Thesis, 2017. http://etd.iisc.ac.in/handle/2005/4282.
Повний текст джерелаАнотація:
Viruses are major pathogenic agents that cause a variety of diseases in all living systems. Since their first isolation in 1892 by Dimitrii Ivanovsky, methods of their diagnosis and control, their life cycles, host - virus interactions, mechanisms of resistance etc have been intensely researched. The first virus ever to be discovered was Tobacco mosaic virus (TMV), a plant virus (Beijerinck, 1898). More than three thousand viruses that infect not only plants, but also humans, animals and bacteria have been described (Koonin et al., 2006 ; Lawrence et al., 2009; King et al., 2012). Over the years, study of viruses has shown that they are obligate parasites and their life cycle stages are analogous to the cellular processes. Interestingly, many of the concepts and tools of molecular biology have been derived from the study of viruses because of their small genomes. The structural and functional simplicity of viruses have made them attractive tools for scientists to study a variety of biological phenomena.
According to the ninth report of the International Committee on Taxonomy of Viruses (ICTV IX) (King et al., 2012) the number of recognized viruses is 3,618, of which ~25% (957) are plant viruses and they have been classified into different families (Fig.1.1). RNA viruses infecting plants are highly abundant and more diverse when compared to DNA viruses (Koonin et al., 2015). Single-stranded RNA viruses have been shown to generally have smaller genomes (average length ~9kb). While this allows the viruses to mutate and evolve faster (Sanjuán and Domingo-Calap, 2016), it also makes it essential for these viruses to encode for multifunctional proteins.
There are seven defined families of positive sense, single stranded RNA plant viruses, namely, Bromoviridae, Closteroviridae, Luteoviridae, Potyviridae, Seconaviridae, Tombusviridae, and Virgaviridae. Among these families, the family Potyviridae contains the largest group of plant viruses that are also economically very important (Martínez et al., 2016). Their genome organization and expression strategies are similar to picornaviruses (Domier et al., 1987) and are therefore classified along with picorna-like superfamily of viruses. According to ICTV classification, the family Potyviridae consists of eight genera and two unassigned species (Table 1.1) based on physical properties of virion, RNA sequence, genome organization and mode of transmission (Wylie et al., 2017). The genus Potyvirus named after its type species, Potato virus Y (Ward and Shukla, 1991; Riechmann et al., 1992) is one of the oldest and the most successful of all known genera comprising of 146 virus species.
21
Roy, Anindya. "Molecular Characterization Of Capsid Protein And Nuclear Inclusion Protein Of Pepper Vein Banding Virus." Thesis, 2004. https://etd.iisc.ac.in/handle/2005/1144.
Повний текст джерела
22
Roy, Anindya. "Molecular Characterization Of Capsid Protein And Nuclear Inclusion Protein Of Pepper Vein Banding Virus." Thesis, 2004. http://etd.iisc.ernet.in/handle/2005/1144.
Повний текст джерела
23
Gomez, Elaine. "Tandem Reactions of Carbon Dioxide Reduction and Hydrocarbon Transformation." Thesis, 2019. https://doi.org/10.7916/d8-pvb5-rr62.
Повний текст джерелаАнотація:
High atmospheric concentrations of CO2 contribute to adverse effects that impact human health and the climate. The need to reduce CO2 is evident, and climate stabilization will require a combination of mitigation, utilization, and even negative emission technologies. Thus, one key approach will be to transform abundant CO2 into a useful feedstock for processes that not only produce value-added products but also match the scale necessary to impact anthropogenic emissions. The tandem CO2 reduction and light alkane transformation reactions over specialized bifunctional catalysts have the potential to produce olefins or synthesis gas by efficiently utilizing the C2-C4 components in shale gas while reducing a greenhouse gas.
The reactions of CO2 with light alkanes may occur through two distinct pathways, oxidative dehydrogenation (CO2 + CnH2n+2 → CnH2n + CO + H2O, CO2-ODH) and dry reforming (nCO2 + CnH2n+2 → 2nCO + (n+1)H2, DR). The two reactions can occur simultaneously at temperatures ≥823 K with considerable conversions. Until recently, there has been little understanding regarding the identification of bimetallic catalytic systems that either selectively cleave the C-H bonds to produce olefins or effectively break all the C-C and C-H bonds to produce dry reforming products. In this work, we discuss a combined approach of flow reactor experiments, in situ characterization, and density functional theory (DFT) calculations to help create a design platform for catalysts that are inherently active and selective for the reactions of CO2 and light alkanes.
Particularly, it was of interest to use propane as CO2 reduction feedstock due to its increasing abundance and highly marketable respective olefin. Through the combined approach, non-precious Fe3Ni1 and precious Ni3Pt1 supported on CeO2 were identified as promising catalysts for the CO2-ODH and DR of propane, respectively. In situ X-ray absorption spectroscopy measurements revealed the oxidation states of metals under reaction conditions and DFT calculations were utilized to identify the most favorable reaction pathways over the two types of catalysts. While both the CO2-ODH and DR reactions of alkanes produce valuable molecules, the separation of gas phase products is challenging. Therefore, it was highly desirable to develop a tandem reaction scheme in which the reaction of CO2 and alkanes can produce liquid products.
Another potential chemistry with increased similarity to the operating conditions of CO2-ODH, is the tandem reactions of CO2-assisted oxidative dehydrogenation and aromatization of light alkanes (CO2-ODA). In this process, alkanes are transformed directly into aromatics without the need for expensive naphtha while increasing the consumption of CO2 per mol of value-added product and facilitating downstream separation because of the production of liquid aromatics. One critical change upon the introduction of CO2 to the dehydrogenation/aromatization pathway is the formation of water. The presence of water under reaction conditions has been shown to be problematic for zeolites as it causes changes in the framework. Phosphorous modification at an optimal loading improved the hydrothermal stability of Ga/ZSM-5, reduced coke formation on the catalyst surface, and allowed for the formation of more liquid aromatics through the CO2-ODAE reaction pathway compared to the direct dehydrogenation and aromatization reaction. With the aid of DFT calculations, the mechanisms for the production of aromatics from ethane were identified, providing insight on the effect of Ga modification on ethylene formation over ZSM-5 as well as the role of CO2 on the aromatization of ethylene. Future efforts should be geared toward enhancing aromatics yield through the design of hydrothermal stable zeolite-based materials with bimetallic active centers that are capable of activating CO2.
24
Mathur, Chhavi. "Characterization Of Structural And Non-structural Proteins Of Positive Sense, Single-stranded RNA Plant Viruses." Thesis, 2012. https://etd.iisc.ac.in/handle/2005/2442.
Повний текст джерелаАнотація:
In the present thesis, two positive sense single-stranded RNA viruses have been used as models to understand the structure and function of viral-encoded proteins. One of them, Pepper Vein Banding Virus (PVBV; genus Potyvirus; family Potyviridae) is a flexuous, rod-shaped virus that encodes for a polyprotein of size ~340 kDa. The polyprotein undergoes proteolytic processing by viral-encoded proteases, of which Nuclear Inclusion-a Protease (NIa-Pro) is the major protease. It is a serine-like cysteine protease which cleaves between a Q/A or Q/S, present in the context of the heptapeptide recognition sequence. The temporal regulation of intermediates and mature proteins released by NIa-Pro cleavage is crucial for a successful infection. In the present study, histidine-tagged NIa-Pro, Viral Protein genome-linked (VPg), and the cleavage site mutant (E191A) VPg-Pro were over-expressed in E. coli and purified. The protease activity of NIa-Pro was monitored using an HPLC-based protease assay developed using a peptide substrate. NIa-Pro protease activity was found to get modulated upon interaction with VPg and upon undergoing phosphorylation. Both these events have been found to involve the face of NIa-Pro which contains the solvent-exposed Trp143. Mutational studies and molecular dynamics analyses provide evidence that this residue is buried upon interaction of NIa-Pro with VPg, and any perturbation of its orientation influences the active site Cys151 via an extensive interaction network. This interaction was found to enhance the velocity of NIa-Pro protease activity, especially if the two domains were present in trans (VPg+Pro). In addition, the main-chain –NH2 group of Trp143 was found to be hydrogen-bonded to the side chain –OH group of Ser129, the residue which was identified to undergo phosphorylation by host plant kinases. Interestingly, when the two domains were present in cis (E191A VPg-Pro), no phosphorylation was observed. Mutations of Ser129 (to phosphorylation-mimic Asp or phosphorylation-deficient Ala residues) which affected this H-bond were found to disturb Trp143 and Cys151 orientation, which drastically reduced the protease activity of NIa-Pro. Within the polyprotein, VPg is present at the N-terminus of NIa-Pro and the cleavage site between them is suboptimal (E/A). In the present study, VPg-Pro was shown to be covalently linked to the genomic RNA present in the virions. Interestingly, during purification, VPg could only be purified from the soluble when it was expressed at the N-terminus of NIa-Pro. A series of bioinformatics and biophysical analysis of VPg showed that PVBV VPg, like other potyviral VPgs, exists as a molten-globule. Moreover, while VPg was shown to harbour the Walker motifs, it was found to exhibit an ATPase activity only when it was present with the NIa-Pro (especially in cis). Lys47 and Asp88:Glu89 were found crucial for optimal activity. Over all the results demonstrated that there is a reciprocal modulation of structure and function of the VPg and NIa-Pro domains. These results can explain the possible significance of an impeded cleavage rate between the two domains of VPg-Pro during PVBV infection. The precursor, VPg-Pro, could offer the advantage of evading the inhibitory phosphorylation of NIa-Pro by the host, as well as drive certain viral processes by virtue of its ATPase activity. And subsequent cleavage of the domains and their trans interaction could offer a higher turnover rate which might assist sufficient CP production required for viral morphogenesis. Another virus, Tobacco Streak Virus (TSV) that belongs to the Ilarvirus genus of the Bromoviridae family is a spherical virus which forms pleiomorphic icosahedral virus particles. It has a tripartite genome and each RNA is encapsidated individually. In the present thesis, TSV was used as a model to understand the properties of its structural protein-the coat protein (CP), with the aim of deciphering TSV assembly process. Thus, the CP gene from TSV RNA 3 was cloned and over-expressed in E. coli. The coat protein thus expressed formed virus-like particles (VLPs), which could be disassembled into dimers using high CaCl2 concentrations. Reassembly of VLPs was possible from dimers even in the absence of any nucleic acid. Mutational analysis of the N-terminal disordered domain showed that 26 amino acid residues from the amino-terminus could be crucial for capsid heterogeneity while, zinc-binding domain was essential for assembly. Overall, the present study shows that the flexible W-C loop of PVBV NIa-Pro, the disordered N-terminal region of PVBV VPg and the disordered N-terminal region of TSV CP harbour residues crucial for regulation of protein function. Such regulatory elements would ultimately allow viruses to maintain a smaller protein number, and thus a smaller genome size.
25
Mathur, Chhavi. "Characterization Of Structural And Non-structural Proteins Of Positive Sense, Single-stranded RNA Plant Viruses." Thesis, 2012. http://etd.iisc.ernet.in/handle/2005/2442.
Повний текст джерелаАнотація:
In the present thesis, two positive sense single-stranded RNA viruses have been used as models to understand the structure and function of viral-encoded proteins. One of them, Pepper Vein Banding Virus (PVBV; genus Potyvirus; family Potyviridae) is a flexuous, rod-shaped virus that encodes for a polyprotein of size ~340 kDa. The polyprotein undergoes proteolytic processing by viral-encoded proteases, of which Nuclear Inclusion-a Protease (NIa-Pro) is the major protease. It is a serine-like cysteine protease which cleaves between a Q/A or Q/S, present in the context of the heptapeptide recognition sequence. The temporal regulation of intermediates and mature proteins released by NIa-Pro cleavage is crucial for a successful infection. In the present study, histidine-tagged NIa-Pro, Viral Protein genome-linked (VPg), and the cleavage site mutant (E191A) VPg-Pro were over-expressed in E. coli and purified. The protease activity of NIa-Pro was monitored using an HPLC-based protease assay developed using a peptide substrate. NIa-Pro protease activity was found to get modulated upon interaction with VPg and upon undergoing phosphorylation. Both these events have been found to involve the face of NIa-Pro which contains the solvent-exposed Trp143. Mutational studies and molecular dynamics analyses provide evidence that this residue is buried upon interaction of NIa-Pro with VPg, and any perturbation of its orientation influences the active site Cys151 via an extensive interaction network. This interaction was found to enhance the velocity of NIa-Pro protease activity, especially if the two domains were present in trans (VPg+Pro). In addition, the main-chain –NH2 group of Trp143 was found to be hydrogen-bonded to the side chain –OH group of Ser129, the residue which was identified to undergo phosphorylation by host plant kinases. Interestingly, when the two domains were present in cis (E191A VPg-Pro), no phosphorylation was observed. Mutations of Ser129 (to phosphorylation-mimic Asp or phosphorylation-deficient Ala residues) which affected this H-bond were found to disturb Trp143 and Cys151 orientation, which drastically reduced the protease activity of NIa-Pro. Within the polyprotein, VPg is present at the N-terminus of NIa-Pro and the cleavage site between them is suboptimal (E/A). In the present study, VPg-Pro was shown to be covalently linked to the genomic RNA present in the virions. Interestingly, during purification, VPg could only be purified from the soluble when it was expressed at the N-terminus of NIa-Pro. A series of bioinformatics and biophysical analysis of VPg showed that PVBV VPg, like other potyviral VPgs, exists as a molten-globule. Moreover, while VPg was shown to harbour the Walker motifs, it was found to exhibit an ATPase activity only when it was present with the NIa-Pro (especially in cis). Lys47 and Asp88:Glu89 were found crucial for optimal activity. Over all the results demonstrated that there is a reciprocal modulation of structure and function of the VPg and NIa-Pro domains. These results can explain the possible significance of an impeded cleavage rate between the two domains of VPg-Pro during PVBV infection. The precursor, VPg-Pro, could offer the advantage of evading the inhibitory phosphorylation of NIa-Pro by the host, as well as drive certain viral processes by virtue of its ATPase activity. And subsequent cleavage of the domains and their trans interaction could offer a higher turnover rate which might assist sufficient CP production required for viral morphogenesis. Another virus, Tobacco Streak Virus (TSV) that belongs to the Ilarvirus genus of the Bromoviridae family is a spherical virus which forms pleiomorphic icosahedral virus particles. It has a tripartite genome and each RNA is encapsidated individually. In the present thesis, TSV was used as a model to understand the properties of its structural protein-the coat protein (CP), with the aim of deciphering TSV assembly process. Thus, the CP gene from TSV RNA 3 was cloned and over-expressed in E. coli. The coat protein thus expressed formed virus-like particles (VLPs), which could be disassembled into dimers using high CaCl2 concentrations. Reassembly of VLPs was possible from dimers even in the absence of any nucleic acid. Mutational analysis of the N-terminal disordered domain showed that 26 amino acid residues from the amino-terminus could be crucial for capsid heterogeneity while, zinc-binding domain was essential for assembly. Overall, the present study shows that the flexible W-C loop of PVBV NIa-Pro, the disordered N-terminal region of PVBV VPg and the disordered N-terminal region of TSV CP harbour residues crucial for regulation of protein function. Such regulatory elements would ultimately allow viruses to maintain a smaller protein number, and thus a smaller genome size.
26
Lai, Chiu-Mei, and 賴秋梅. "Optimal heating process of double-layer annular cylinders composed of PVB/Ni and PVB/YSZ." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/62383214483153343008.
Повний текст джерелаАнотація:
碩士元智大學
化學工程與材料科學學系
96
The optimum heating trajectories of fabricating Ni/PVB and YSZ/PVB double-layer cylinder in different sample size and geometric proportional condition were successfully simulated. The system model is described by transport equation and the dynamic equation of polymer degradation. The dynamic optimization of polymer binder burnout processes was evaluated for a 2-D bi-layer cylinder in different sample porosities and atmospheres. Optimal heating trajectories of the binder removal processes to minimize the burnout time were estimated by the proposed algorithm. The process model can be constructed by chemical kinetics of the polymer burnout and the mass transport of volatile gas evolved from polymer burnout inside the bi-layer cylinder. The results show that the ceramic center pressure will increase when heating rate increase. Sample size will affect build-up pressure generation in ceramic center The pressure is higher for the PVB/YSZ-inside and PVB/Ni-outside (CiMo) samples than the PVB/Ni-inside and PVB/YSZ-outside(CoMi) case. The reaction time of CoMi case is earlier than the one of CiMo case. The optimal heating trajectories was determined by the dynamic optimization method. It also can improve productivity and reduce the cost of process time further.
27
Hsia-YuTai and 戴遐妤. "Mixing aerogels into PVB films used for laminated glazing." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/83650570970211140090.
Повний текст джерелаАнотація:
碩士國立成功大學
機械工程學系
103
This research focus on adding aerogel into PVB and make PVB films, also assemble PVB film with glazing into laminated glazing. With observation and characterization of PVB film and laminated glass. We recognize the advantages and disadvantages of different process, which give us idea of improving. In addition, the research also involved in improving the preparation of aerogels. In this research, the result shows that now the PVB film which aerogel added haven’t manage to have good insulation property meanwhile keep the optic transmittance. In process1, process2, process4, the PVB film didn’t improve in insulation property. In process 3 and process 5, the insulation property improves due to thermal conductivity declined, however, the films from these processes came across the missing of light transmittance. For laminated glazing, we adopted the films made in process 5, and in two different recipes. The result shows that the laminated glass with PVB films containing aerogel had lower thermal conductivity compared to those with pure PVB films, UV transmittance and shading coefficient(SC) all declined, but visible light transmittance declined, too. Although there are some improvement in laminated glass when aerogel added, we still have to improve to in order to meet the standard of green building material.
28
Luo, Chuang-yu, and 羅創宇. "Synthesis of ZnS/PVB nanocomposite fiber and ZnS nanoparticle." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/22886917996277170580.
Повний текст джерелаАнотація:
碩士國立臺南大學
材料科學系碩士班
101
In this study by use the electrospinning technique to prepared the ZnS/PVB nanofiber precursor. In the synthesis process could be prepared the thin ZnS/PVB nanofiber precursor by adjust voltage, flow rate, working distance and the PVB wt%. And finally calcination these ZnS/PVB nanofiber to synthesis ZnS nanomaterial. Another experimental, through hydrothermal method to synthesis ZnS nanofiber by used the ZnS/PVB nanofiber precursor, in the hydrothermal process by change the reaction solvent to synthesis ZnS. For example,1:X ( X=1-7 ) volume ratio of DI water and ethylenediamine,1:X ( X=1-7 ) volume ratio of ethylenediamine ,1:1 volume ratio of DI water and ethylenediamine and DI water, ethylenediamine and DI water. Finally, by using the XRD、SEM、TEM and EDX to analysis the product of the structure and morpgology.
29
Gonçalves, Manuel António Soares Arieiro. "Análise comparativa de intercalares para vidro estrutural: SGP | PVB. Ações de curta e longa duração." Master's thesis, 2019. http://hdl.handle.net/10316/93514.
Повний текст джерелаАнотація:
Dissertação de Mestrado Integrado em Engenharia Civil apresentada à Faculdade de Ciências e TecnologiaApesar de ser um material relativamente recente na construção, o vidro é, hoje em dia, cada vez mais requisitado tanto por arquitectos, como por donos de obra, que com este implementam nos edifícios uma certa ideia de futuro. O vidro tem também um grande potencial energético, que caso não seja bem estudado e revisto poderá traduzir-se em problemas graves quer para o edifício quer para as pessoas que o utilizam, podendo criar o chamado “efeito de estufa”, o que levará ao problema de eficiência energética a médio e longo prazo, facto que é tão debatido na actualidade.Assim é necessária a colmatação de algumas falhas na regulamentação vidreira, nomeadamente no fabrico, transporte e dimensionamento de vidro estrutural. Estas lacunas traduzem-se em montantes avultados gastos pelos construtores a ensaiar modelos à escala real, já que cada edifício assim construído, é por si só um caso de estudo, não havendo um procedimento a seguir para dimensionar vidro estrutural. Faltam normas de qualidade, dado que neste momento cada empresa vidreira produz por si só, faltam normas para o transporte e acondicionamento do vidro, que é por natureza um material frágil. Tudo isto faz com que o projetista não saiba ao certo a qualidade do vidro que chega à obra.Nesta dissertação pretende-se colmatar algumas dessas lacunas especialmente na forma como se utiliza uma das inúmeras soluções, o vidro laminado, nomeadamente a sua resistência e a capacidade de carga mesmo após a quebra. Para colmatar este conhecimento pretende-se analisar laboratorialmente o comportamento de diferentes tipos de laminação e comparar os seus resultados.A partir deste trabalho tenciona-se preparar um modelo numérico para tornar mais expedita e sustentável a aplicação deste tipo de solução, sem ser necessário recorrer a práticas experimentais à escala real cada vez que seja necessário implementar uma solução deste tipo.
Nowadays glass is increasingly required, both by architects and by owners since it is a relatively a recent material, which represents a certain idea of the future. The glass also has a great energetic potential, that if it is not well studied and revised it can translate into serious problems for both the building and the people who use it. Glass is capable of creating the so-called "greenhouse effect" that will lead to the medium and long term energy efficiency problem, a problem that is hotly debated today.To make this possible and feasible, it is necessary to fill some flaws in glass regulation, namely in the manufacture of structural glass transport and dimensioning. These gaps cause builders to spend large amounts only on rehearsing full-scale models, since each building is itself a case study, and there is no procedure to be followed to design structural glass. Quality standards are lacking since each glass company produces by itself, there are no standard for the transportation and packaging of glass, which is by nature fragile. This makes the designer not know for sure the quality of the glass that comes to the construction site.This dissertation intends to fill some of these gaps, particularly in the use of laminated glass, namely its strength and load capacity even after breaking. To fill this knowledge, we intend to analyze the behavior of different types of laminations and compare their results.From this work we intend to prepare a numerical model to make the application of this type of solution more expeditious and sustainable, without having to resort to real-scale experimental practices whenever a solution needs to be implemented.
30
Channa, I. A., A. D. Chandio, M. Rizwan, A. A. Shah, J. Bhatti, A. K. Shah, F. Hussain, Muhammad A. Shar, and A. AlHazaa. "Solution processed PVB/mica flake coatings for the encapsulation of organic solar cells." 2021. http://hdl.handle.net/10454/18504.
Повний текст джерелаАнотація:
YesOrganic photovoltaics (OPVs) die due to their interactions with environmental gases, i.e., moisture and oxygen, the latter being the most dangerous, especially under illumination, due to the fact that most of the active layers used in OPVs are extremely sensitive to oxygen. In this work we demonstrate solution-based effective barrier coatings based on composite of poly(vinyl butyral) (PVB)and mica flakes for the protection of poly (3-hexylthiophene) (P3HT)-based organic solar cells (OSCs)against photobleaching under illumination conditions. In the first step we developed a protective layer with cost effective and environmentally friendly methods and optimized its properties in terms of transparency, barrier improvement factor, and bendability. The developed protective layer maintained a high transparency in the visible region and improved oxygen and moisture barrier quality by the factor of ~7. The resultant protective layers showed ultra-flexibility, as no significant degradation in protective characteristics were observed after 10 K bending cycles. In the second step, a PVB/mica composite layer was applied on top of the P3HT film and subjected to photo-degradation. The P3HT films coated with PVB/mica composite showed improved stability under constant light irradiation and exhibited a loss of <20% of the initial optical density over the period of 150 h. Finally, optimized barrier layers were used as encapsulation for organic solar cell (OSC) devices. The lifetime results confirmed that the stability of the OSCs was extended from few hours to over 240 h in a sun test (65◦C, ambient RH%) which corresponds to an enhanced lifetime by a factor of 9 compared to devices encapsulated with pristine PVB.
Higher Education Commission of Pakistan through NED University of Engineering and Technology, Karachi, Pakistan and “The APC was funded by Deanship of Scientific Research, King Saud University for funding through Vice Deanship of Scientific Research Chairs”.
31
lin, Ying-Chich, and 林英傑. "The Effects of PVB Elastomer Contents for Toughed Nylon 6,6 on Mechanical Properties." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/15337071494346933258.
Повний текст джерелаАнотація:
碩士中國文化大學
造紙印刷研究所
86
ABSTRACT The toughed effects of PA66 modified with recycled scrap material, polyvinyl butyral (PVB), blending with SEBS-g-MA (Kraton 1901X) are discussed. Typical systems include PA66/SEBS-g-MA=85/15, 75/25 and PA66/SEBS-g-MA/SEBS=80/10/10 repectively. Besides understanding what''''s the role of PVB in the system, the importance of twin-screw configurations is emphasized in this study. Based on morphology, rheology and mechanical properties, the interaction compatibilizer and PVB for PA66/SEBS-g- MA=85/15 system including the effects of twin-screw configurations can be understood. The results show tensile modulus increases from 2161 MPa to 2602 MPa with increasing amounts of PVB from 0 wt% to 7 wt%； and slight decrease in elongation from 72.9% to 48.3%. The impact strength at room temperature decreases from 1034.4 J/m to 360.5 J/m for PA66/SEBS-g-MA=75/25 system in 1/4 inch. Meanwhile, the bttle-ductile transition temperature (DBTT) increases with increasing from -5℃ to none in 1/4 inch, similar trends obtained in other systems. i.e., increase in modulus, DBTT and decrease in elongation and impact strength. However, in a certain system like PA66/SEBS-g-MA/PVB=75/22/3, 85/14/1, the slight change in mechanical properties is found with suitable amounts of substitution for instance, impact strength of 1122.4 J/m for PA66/SEBS-g-MA/PVB=/22/3 in 1/8 inch is still acceptable in the industry. This might be attributed to the low interfacial bonding of PVB with nylon in view of morphology. Generally speaking, the viscosity drops with increasing the amount of PVB. Through morphology observing, its particle size is larger when PVB contents are higher. The range is from 0.23 (m to 0.95 (m. It indicated PVB and SEBS-g-MA can''''t form core-shell structure, thus the impact streng reduced due to the addition of PVB. The certain level of kneading disk could improve the mixing performance. Therefore, the higher impact strength could also be reached.
32
Bora, Pritom Jyoti. "Design and Tailoring of Polymer Composite Ultra-thin Films for Electromagnetic Interference Shielding." Thesis, 2017. https://etd.iisc.ac.in/handle/2005/4728.
Повний текст джерелаАнотація:
Electromagnetic interference (EMI) is a serious issue. Lightweight, flexible polymer nanocomposite materials have been a key interest for EMI shielding and microwave absorption due to many advantages over traditionally used metal sheets. This work is about design and tailoring of polymer composites and its film for absorption of predominant EMI shielding. It consists of four major parts, viz., (i) materials tuning, (ii) morphology tuning, (iii) electromagnetic (EM) property study of polymer composite and (iv) EM simulation. In case of materials tuning, the base material is taken as fly ash cenosphere (FAC) which is an industrial waste, whereas weather resistive PVB is taken as the base polymer matrix.
In Chapter 1, the motivation for the thesis is established, based on literature and current challenges in EMI shielding materials. The issues of polymer composite for real time EMI shielding application are addressed and discussed. These issues are mainly lightweight, thickness, processing, flexibility, weather resistivity, morphology and most importantly coat ability. This is the reason for attraction towards ultra-thin polymer composite film for EMI shielding.
In Chapter 2, the polymer composite design approach, EMI shielding measurement technique and simulation procedures adopted in the thesis are detailed. The EMI shielding effectiveness measurement through waveguide method by using vector network analyzer (VNA) is discussed here, along with details of the EM characterization methods employed. Secondly, the basic mechanism of EMI shielding and reflection loss in the materials and films are discussed. The EM simulation methodologies used are also discussed. These simulations concern the complex S-parameters and absorption power, which are common across a large portion of the thesis. Simulation which are specific to a particular portion are explained in the appropriate places in the corresponding chapters.
Chapter 3 is the most important chapter of this thesis. In this chapter, the utilization of industrial waste FAC based polymer composites and its film for EM applications is studied. Both experimental and simulated results are discussed. FAC is metal and metal oxide coated by chemical and electroless method and dielectrics/absorption property is studied. The coating thickness is optimized based on the absorption property. Further, in situ conducting polymer (Polyaniline or PANI) composite synthesis is carried out and solution processed to prepare ultra-thin films. Two case studies are considered here. In the first case, PANI/FAC based composites were used as a filler in PVB, Secondly, PANI/FAC composites are directly solution processed. The EMI SE of these ultra-thin films are investigated with shielding mechanism. Based on the understanding of this chapter, morphology tuning of the polymer composites was considered in the next chapter.
In Chapter 4, the morphology tuning of polymer nanocomposite for EMI shielding and absorption was studied. As a case study, the manganese di-oxide (MnO2) was taken and morphologically different nanostructures were synthesized using standard chemical methods and polymer nanocomposite is prepared. Based on obtained reflection loss (RL), in situ conducting polymer-MnO2 nanorod composite was synthesized and free standing ultra-thin film was prepared by solution processing. The EMI SE and shielding mechanism of these films were investigated. Based on the understanding of this chapter, PVB-conducting polymer nanocomposite films were designed for EMI shielding, which is discussed in the next chapter.
In Chapter 5, EMI SE of PVB–PANI nanofiber composite film was studied. PANI nanofiber was synthesized by standard chemical procedure at low temperature and characterized. PVBPANI nanofiber composites were prepared by simple solution casting and characterized. The results indicate that the PVB-PANI nanofiber composite film has better EMI shielding and shielding due to absorption property, as compared to PVB-PANI composite films. Thus, based on this understanding, another conducting polymer, PEDOT:PSS, based novel PVBPEDOT:PSS hybrid composite films were synthesized and discussed in the next chapter.
In Chapter 6, novel hybrid PVB-PEDOT:PSS based ultra-thin composite films for EMI shielding were designed. Initially, PVB-PEDOT:PSS ratio was optimized with a potential shielding effectiveness. Secondly, EMI SE of this PVB-PEDOT:PSS film was enhanced by introducing conducting, optimized nickel coated glass fabric. Finally, for more specific EMI shielding applications, optically transparent PVB-PEDOT:PSS-ITO ultra-thin hybrid film was prepared with an appreciable shielding effectiveness.
In summary, this thesis has made contribution towards design and tailoring of absorption predominant EMI shielding enhancement of polymer composites based on industrial waste, metal, metal oxide, conducting polymer and conducting glass fabric, and its ultra-thin film having large area coat ability. All the properties were optimized keeping in mind the final polymer composite should be used as a coated film rather than a thick pellet. In a nutshell, in these studies more than 99 % of EMI shielding was demonstrated.
33
Tung, Ming-Te, and 童明德. "Investigation of PVB binder photo-degradation by nano-Titanium photo-catalyst in green ceramic body." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/96632848923465767955.
Повний текст джерелаАнотація:
碩士元智大學
化學工程學系
93
Solid-phase photocatalytic degradation of PVB (poly(vinyl butyral)) with nano-TiO2 as photocatalyst was investigated in the room temperature under ultraviolet light irradiation. Kinetic parameters of the composite sample were estimated by thermogravimetry (TG) measurements. Solid-phase photocatalytic reaction mechanism of PVB/TiO2 sample is conducted by diffuse reflectance Fourier transform spectroscopy (DRIFTS). The morphologies of irradiated PVB/TiO2 samples were carried out by using scanning electron microscope (SEM) and atomic forces microscope (AFM) analysis. Results revealed that photo-degradation of PVB binder are removable. The kinetic analysis of the PVB photo-degradation was carried out. The PVB photo-degradation experiments exhibit that higher composition of TiO2, near distance of UV lighting; thinner coating films and the use of glass substrate can accelerate the degradation rate. In addition, the PVB photo-degradation rate can be increased when wet air condition was applied. Furthermore, the degradation mechanism was proposed from the analytical results.
34
Hsieh, Yu-Ping, and 謝俞枰. "Kinetic Analysis of Thermal degradation of PVB/Glass Ceramic with Nano-Silica in LTCC processing." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/80096487621326323723.
Повний текст джерелаАнотація:
碩士元智大學
化學工程學系
92
Kinetic analysis of thermal degradation of poly(vinyl butyral)(PVB)/glass ceramic with nano-silica was investigated in different atmosphere, composition, and operating conditions. Kinetic triplets and reaction pathways of the composite sample were analyzed by thermogravimetry (TG) and Fourier-Transform Infrared spectroscopy (FT-IR) measurements using the proposed algorithm. Results of the kinetic analysis revealed that the thermal degradation mechanism of the composites is multiple reaction steps. In nitrogen atmosphere, the degradation temperature of the composites is higher because of the presence of nano-silica. In air atmosphere, the effects of nano-silica on PVB/ glass ceramic thermal degradation were verified by detecting the volatile gas.
35
Marinho, Bruno Filipe dos Santos. "Caracterização experimental do vidro laminado como material estrutural : avaliação da influência dos elementos intercalares e da temperatura." Master's thesis, 2012. http://hdl.handle.net/1822/29648.
Повний текст джерелаАнотація:
Dissertação de mestrado integrado em Engenharia CivilA transformação no uso do vidro a que se assistiu nas últimas décadas deve-se, entre outros fatores, às novas tendências arquitetónicas e à evolução tecnológica associada à produção deste material. Verifica-se, desde o início do século passado, a sua utilização em grande escala na construção, tornando-se necessário o desenvolvimento de novos conhecimentos e soluções no âmbito das suas propriedades químicas e físicas, de forma a satisfazer os requisitos impostos pelas mais arrojadas obras atualmente construídas. Assim, a acompanhar esta tendência, assiste-se a uma preocupação crescente em considerar questões de segurança no que respeita à sua utilização com funções estruturais. Sabe-se que o vidro, quando utilizado como material estrutural, apresenta algumas desvantagens em relação a outros materiais tradicionais, salientando-se a reduzida resistência à tração e o comportamento frágil. Uma das soluções encontradas para aumentar a sua resistência pós-rotura é a associação a um outro material. A laminação é a técnica mais frequente, onde o vidro é associado a um polímero de modo a conseguir um comportamento mais seguro com a utilização de múltiplas camadas. Apesar dos desenvolvimentos recentes, os engenheiros de estruturas continuam a ter dificuldade em tomar decisões relacionadas com a utilização de vidro estrutural, tais como: o número de camadas a utilizar; a espessura das respetivas camadas; o número de películas intercalares; a resistência exigida após a rotura; o período em que é necessário assegurar essa resistência; o tipo de películas intercalares, entre outras. Tendo estes constrangimentos como base, recorreu-se à realização de ensaios experimentais com o objetivo de avaliar fenómenos relevantes do comportamento estrutural do vidro laminado. Nestes ensaios, procurou-se medira influência da variação da temperatura e a influência do tipo de material intercalar utilizado. Complementarmente, procurou-se testar a presença de um reforço que consiste numa chapa fina e perfurada de aço inoxidável posicionada na camada intercalar dos dois vidros. O objetivo é avaliar a sua contribuição para a capacidade resistente e ductilidade do composto laminado.
The use of glass in recent decades is due, among other factors, to new architectural trends and developments in technology associated with the production of this material. From the beginning of the last century, it has been widely used in construction, making it increasingly necessary to develop new knowledge and solutions concerning their physical and chemical properties, in order to meet the requirements imposed by the boldest buildings currently constructed. Following this trend, there has been a growing concern in considering safety issues related to its structural use in buildings. It is known that glass, used as a structural material, has some disadvantages compared to other traditional materials, in particular, reduced tensile strength and brittle behavior. One of the solutions to increase strength after breakdown is to combine glass with other materials. Lamination is the most common technique, where the glass is linked to a polymer in order to achieve a safer behavior with the use of multiple layers. Despite recent developments, structural engineers still have some difficulties in taking decisions regarding the use of a glass structure, such as the number of layers to be used, the thickness of the respective layers, the number, the type and the thickness of intermediate films, the required strength after breakage, the time that is necessary to ensure that resistance, among others. Taking these issues into consideration, it was decided to perform experimental tests in order to evaluate relevant phenomena associated with the structural behavior of laminated glass. These tests tried to evaluate the influence of temperature variation and the influence of the type of interlayer used. In addition, specimens strengthened with a thin plate of perforated stainless steel positioned between the two glass sheets was fabricated and tested, in order to assess their contribution to the bearing capacity and ductility of the composite laminate.
36
童明德. "柰米二氧化鈦光觸媒對陶瓷坯體中之高分子黏結劑 PVB 光裂解探討". Thesis, 2005. http://ndltd.ncl.edu.tw/handle/79204515949822837484.
Повний текст джерела