Dissertations / Theses on the topic 'Smart Materials'
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Kuruwita-Mudiyanselage, Thilini D. "Smart Polymer Materials." Bowling Green State University / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1223652552.
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Taiwo, Adetoun. "SMART SUPERHYDROPHOBIC MATERIALS." VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/3209.
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Superhydrophobicity refers to surfaces with extremely large water droplet contact angles (usually greater than 150°). This phenomenon requires a hydrophobic material with micro or nano-scale roughness. Superhydrophobic surfaces exist in nature (e.g. the lotus leaf) and can be produced synthetically. This project focuses on the development and characterization of superhydrophobic materials with tunable wettability (i.e. smart superhydrophobic materials). In this study, surfaces were prepared by electrospinning thin, aligned polystyrene fibers onto a piezoelectric unimorph substrate. Results showed electric field induced changes in substrate curvature, which produced corresponding changes in surface wettability. From experiments, an average change in water contact angle of 7.2° ± 1.2° with 90% confidence was observed in ~2μm diameter fiber coatings electrospun for 5 minutes with applied electric field. In addition, fiber coatings electrospun with equivalent deposition showed average electric field induced changes in WCA of 2.5° ± 0.92° for lower diameter fibers (~1μm) and 3.5° ± 1.37° for higher diameter fibers (~2μm) with 90% confidence.
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Yan, Zhuoqun. "Smart materials in dentistry." Thesis, University of Newcastle Upon Tyne, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430701.
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Kang, Inpil. "Carbon Nanotube Smart Materials." University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1109710134.
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Matta, Micaela <1987>. "Simulation of Smart Materials." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/6813/1/phd_MicaelaMatta.pdf.
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The aim of this thesis is the elucidation of structure-properties relationship of molecular semiconductors for electronic devices. This involves the use of a comprehensive set of simulation techniques, ranging from quantum-mechanical to numerical stochastic methods, and also the development of ad-hoc computational tools. In more detail, the research activity regarded two main topics: the study of electronic properties and structural behaviour of liquid crystalline (LC) materials based on functionalised oligo(p-phenyleneethynylene) (OPE), and the investigation on the electric field effect associated to OFET operation on pentacene thin film stability.
In this dissertation, a novel family of substituted OPE liquid crystals with applications in stimuli-responsive materials is presented. In more detail, simulations can not only provide evidence for the characterization of the liquid crystalline phases of different OPEs, but elucidate the role of charge transfer states in donor-acceptor LCs containing an endohedral metallofullerene moiety. Such systems can be regarded as promising candidates for organic photovoltaics. Furthermore, exciton dynamics simulations are performed as a way to obtain additional information about the degree of order in OPE columnar phases.
Finally, ab initio and molecular mechanics simulations are used to investigate the influence of an applied electric field on pentacene reactivity and stability. The reaction path of pentacene thermal dimerization in the presence of an external electric field is investigated; the results can be related to the fatigue effect observed in OFETs, that show significant performance degradation even in the absence of external agents. In addition to this, the effect of the gate voltage on a pentacene monolayer are simulated, and the results are then compared to X-ray diffraction measurements performed for the first time on operating OFETs.
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Matta, Micaela <1987>. "Simulation of Smart Materials." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/6813/.
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The aim of this thesis is the elucidation of structure-properties relationship of molecular semiconductors for electronic devices. This involves the use of a comprehensive set of simulation techniques, ranging from quantum-mechanical to numerical stochastic methods, and also the development of ad-hoc computational tools. In more detail, the research activity regarded two main topics: the study of electronic properties and structural behaviour of liquid crystalline (LC) materials based on functionalised oligo(p-phenyleneethynylene) (OPE), and the investigation on the electric field effect associated to OFET operation on pentacene thin film stability.
In this dissertation, a novel family of substituted OPE liquid crystals with applications in stimuli-responsive materials is presented. In more detail, simulations can not only provide evidence for the characterization of the liquid crystalline phases of different OPEs, but elucidate the role of charge transfer states in donor-acceptor LCs containing an endohedral metallofullerene moiety. Such systems can be regarded as promising candidates for organic photovoltaics. Furthermore, exciton dynamics simulations are performed as a way to obtain additional information about the degree of order in OPE columnar phases.
Finally, ab initio and molecular mechanics simulations are used to investigate the influence of an applied electric field on pentacene reactivity and stability. The reaction path of pentacene thermal dimerization in the presence of an external electric field is investigated; the results can be related to the fatigue effect observed in OFETs, that show significant performance degradation even in the absence of external agents. In addition to this, the effect of the gate voltage on a pentacene monolayer are simulated, and the results are then compared to X-ray diffraction measurements performed for the first time on operating OFETs.
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Becker, Ulrike. "Smart Surfaces in Biobased Materials." Diss., Virginia Tech, 1998. http://hdl.handle.net/10919/30714.
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The self-assembly blends of cellulose propionate (CP) and fluorine (F)-containing cellulose derivatives was examined on a model system of solvent cast films. The F-containing derivatives were either high molecular weight statistical cellulose esters with a number of F-containing substituent evenly distributed along the backbone (F-esters), or F-terminated CP-segments with exactly one F-containing endgroup. The F-esters were synthesized in a homogeneous phase and identified by 19F-NMR. Thermal analysis showed improved thermal stability of the F-esters when compared to F-free derivatives.
1-monohydroxy functionalized CP-segments were synthesized by HBr depolymerization using either a commercially available CP with residual OH-groups or a perpropionylated CP (CTP). The hydrolysis using the commercial CP yielded only segments of a minimum DP of 50 and the Mark-Houwink constant declined from 1 to 0.6. The results indicate that in the presence of free hydroxyls branches are formed by transglycosidation. The hydrolysis from perpropionylated CP resulted in segments with a minimum DP of 7, which is in accordance to previous studies.
F-terminated CP segments were synthesized by coupling of the appropriate F-containing alcohol to the CP segment via toluene diisocyanate.
Solutions containing F-terminated CP-segments showed typical critical micelle behavior. The critical micelle concentration depended on the molecular weight of the CP segment and the type of F-containing endgroup. The micelles are thought to consist of a core of the F-endgroups and a corona made-up of CP. Films containing the oligomers cast from micellar solution revealed a linear decrease in wetting force according to the blend composition of the oligomer, i.e. behavior according to the rule of mixing. This indicated the absence of surface segregation of the F-endgroup and it is explained with the fact that the micellar structure is retained in the solid state, suppressing surface segregation. The solid state micelles were visualized as dome-like protrusions by height image atomic force microscopy. In systems blended with CP the distance between the protrusions was found to increase with increasing CP content which was explained by a dilution process.
Films containing F-esters were characterized by wetting force measurements and x-ray photoelectron spectroscopy (XPS). The wetting force decreased dramatically at low blend content of the F-ester and at the same time an F surface-concentration higher then expected from the blend composition was found by XPS. This indicated self-assembly by surface segregation of the F-containing species during film formation. The extent of surface segregation was found to depend on the type of the F-ester group as well as on the blend concentration of the F-ester.
Dynamic wetting force measurements revealed hysteresis in films containing either F-esters or F-terminated CP segments. The hysteresis was found to be both kinetic (water sorption and reorganization) and thermodynamic (surface roughness and surface coverage with F-moieties) in nature. Consecutive force loops revealed an increase in the wetting force (advancing and receding) with increasing loop number, indicating the increased hydrophobicity of the surface. The force increase was determined to be due to water sorption as well as due to surface reorganization. An increase in the size of the F-groups signified a decrease in reorganization rate due to a decreased mobility of the group. The process of reorganization was fully reversible, a behavior which is congruent with the definition of smart behavior.Ph. D.
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LENARDA, ANNA. "Smart materials for energy applications." Doctoral thesis, Università degli Studi di Trieste, 2019. http://hdl.handle.net/11368/2991056.
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In the last decades, electrochemistry has been regarded as a powerful tool to address some of the key challenges that in the framework of sustainability and green energy. In particular, the application of smart, hierarchical materials as electrocatalysts is generating new opportunities for interesting developments. Nanostructured carbon has been heavily employed as a fundamental component for the proposed catalytic materials due to its outstanding electronic and textural properties. This thesis focuses on the exploitation of strategically designed materials based on carbon as electrocatalysts to be used in devices such as new generation fuel cells, electrolyzers for the production of hydrogen peroxide and sensors for its electrochemical detection. Each of these devices is envisioned as a way of reducing the environmental impact, by either being a sustainable source of energy, or substituting energy consuming and non-environmentally friendly processes. In particular, a hybrid Pd/CeO2/C material, prepared through a strategic protocol that allows an intimate contact among the three phases, has been employed as anodic electrocatalyst in both Anion Exchange Membrane Fuel Cells (AEM-FC) and Direct Alcohol Fuel Cells (DAFCs) working in alkaline media and fed with biomass derived polyalcohols. Concerning H2O2 electrosynthesis, N-doped carbon embedding Co nanoparticles have been studied for the Oxygen Reduction Reaction (ORR) in acidic environment, and the material’s outstanding selectivity has been correlated to its N-type species distribution, as well as its porosity and the indirect electronic interaction between the doped carbon phase and the internal metal. Finally, a metal-free electrosensor for the detection of hydrogen peroxide has been produced exploiting the electronic properties of a -COOH decorated graphene, obtained through a controlled functionalization protocol. In all cases, the strategic synthetic procedure gives rise to materials with enhanced catalytic performances in terms of activity, selectivity and stability, and the work has been communicated through publication (already published or in the process of being published) in peer-reviewed journals.In the last decades, electrochemistry has been regarded as a powerful tool to address some of the key challenges that in the framework of sustainability and green energy. In particular, the application of smart, hierarchical materials as electrocatalysts is generating new opportunities for interesting developments. Nanostructured carbon has been heavily employed as a fundamental component for the proposed catalytic materials due to its outstanding electronic and textural properties. This thesis focuses on the exploitation of strategically designed materials based on carbon as electrocatalysts to be used in devices such as new generation fuel cells, electrolyzers for the production of hydrogen peroxide and sensors for its electrochemical detection. Each of these devices is envisioned as a way of reducing the environmental impact, by either being a sustainable source of energy, or substituting energy consuming and non-environmentally friendly processes. In particular, a hybrid Pd/CeO2/C material, prepared through a strategic protocol that allows an intimate contact among the three phases, has been employed as anodic electrocatalyst in both Anion Exchange Membrane Fuel Cells (AEM-FC) and Direct Alcohol Fuel Cells (DAFCs) working in alkaline media and fed with biomass derived polyalcohols. Concerning H2O2 electrosynthesis, N-doped carbon embedding Co nanoparticles have been studied for the Oxygen Reduction Reaction (ORR) in acidic environment, and the material’s outstanding selectivity has been correlated to its N-type species distribution, as well as its porosity and the indirect electronic interaction between the doped carbon phase and the internal metal. Finally, a metal-free electrosensor for the detection of hydrogen peroxide has been produced exploiting the electronic properties of a -COOH decorated graphene, obtained through a controlled functionalization protocol. In all cases, the strategic synthetic procedure gives rise to materials with enhanced catalytic performances in terms of activity, selectivity and stability, and the work has been communicated through publication (already published or in the process of being published) in peer-reviewed journals.
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Molloy, Paul. "Smart materials for subsea buoyancy control." Thesis, University of Glasgow, 2000. http://theses.gla.ac.uk/6161/.
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Buoyancy control is needed in small autonomous underwater devices to enable greater flexibility in measurements in the ocean. This project has examined a number of ways in which buoyancy changes might be achieved. Firstly, an extensive review of the mechanisms by which various marine organisms control their buoyancy was undertaken. There is a tremendous diversity of natural buoyancy control mechanisms, but most of these mechanisms produce only slow (and small) changes in buoyancy. Studies were carried out on the behaviour of polymer gel systems that exhibit large volume changes under the influence of solvent composition and/or temperature. The effects of salinity were investigated, from 5 parts per thousand (ppt) to 35ppt, on hydrolysed polyacrylamide gels, over the temperature range of 5°C to 40°C. It was found that the gels decreased in volume in the solutions, this effect being most pronounced in the 35ppt solution. As temperature increased, the volume changes were observed to decrease. The cyclical volumetric strain behaviour of the polyacrylamide gels, by alternate exposure to saline solutions and distilled water, resulted in significant (~200%) volume changes induced over periods of 2 days. In a second study, the density change associated with the volumetric strain of polymeric materials was investigated in poly(N-isopropylacrylamide), NIPA, gels. The temperature-sensitive NIPA gels, immersed in distilled water or seawater solutions at temperatures ranging from 5°C to 50°C, exhibited volume changes of over 800%, and density changes of 30-40%. NIPA gels exhibit a faster response time than polyacrylamide gels, and their density and volume changes have potential application in buoyancy change. Experiments were also performed on NiTi shape memory alloys (SMA), which change in length and mechanical properties with temperature. A controllable parallel-plate device was constructed, linked by four helical SMA springs, which exerted significant axial forces with the application of temperature. The device is capable of producing substantial volume changes if contained in a suitable enclosure. It is currently on loan to the Science Museum, London, as part of a new exhibition of the Wellcome Wing.
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Shelvay, Alicia M. (Alicia Margaret). "Reinforced concrete : applicability of smart materials." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/74413.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 44-46).
With aging infrastructure, not only in the United States, but worldwide, we look toward designing structures which can withstand the test of time. Creating structures that can adapt to changes in the environment and provide better performance is at the forefront of current research. Reinforced concrete, one of the most widely used materials, can be reinvented using this philosophy. In this thesis, smart materials are classified as materials which can provide sensing, actuation or self-repair. Three different smart materials were studied including self-healing concrete which provides self-repair, shape memory alloys as reinforcement for reinforced concrete which provides actuation and carbon fiber reinforced concrete which provides sensing. It was found that each smart material had potential to improve the performance of reinforced concrete structures. Factors that affect larger scale implementation are discussed.
by Alicia M. Shelvay.
M.Eng.
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Trevor, Susie. "pH responsive chitosan based 'smart' materials." Thesis, University of Cambridge, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.613408.
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Kumpfer, Justin Richard. "Utilizing Metallosupramolecular Polymers as Smart Materials." Case Western Reserve University School of Graduate Studies / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=case1333553702.
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Shah, Syed Asim Ali. "Micro-mechanics modelling of smart materials." Thesis, Sheffield Hallam University, 2016. http://shura.shu.ac.uk/20349/.
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Metal Matrix ceramic-reinforced composites are rapidly becoming strong candidates as structural materials for many high temperature and engineering applications. Metal matrix composites (MMC) combine the ductile properties of the matrix with a brittle phase of the reinforcement, leading to high stiffness and strength with a reduction in structural weight. The main objective of using a metal matrix composite system is to increase service temperature or improve specific mechanical properties of structural components by replacing existing super alloys. The purpose of the study is to investigate, develop and implement second phase reinforcement alloy strengthening empirical model with SiCp reinforced A359 aluminium alloy composites on the particle-matrix interface and the overall mechanical properties of the material. To predict the interfacial fracture strength of aluminium, in the presence of silicon segregation, an empirical model has been modified. This model considers the interfacial energy caused by segregation of impurities at the interface and uses Griffith crack type arguments to predict the formation energies of impurities at the interface. Based on this, model simulations were conducted at nano scale specifically at the interface and the interfacial strengthening behaviour of reinforced aluminium alloy system was expressed in terms of elastic modulus. The numerical model shows success in making prediction possible of trends in relation to segregation and interfacial fracture strength behaviour in SiC particle-reinforced aluminium matrix composites. The simulation models using various micro scale modelling techniques to the aluminum alloy matrix composite, strengthenedwith varying amounts of silicon carbide particulate were done to predict the material state at critical points with properties of Al-SiC which had been heat treated. In this study an algorithm is developed to model a hard ceramic particle in a soft matrix with a clear distinct interface and a strain based relationship has been proposed for the strengthening behaviour of the MMC at the interface rather than stress based, by successfully completing the numerical modelling of particulate reinforced metal matrix composites.
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Baruah, Arabinda. "Smart nanostructured materials for water purification." Thesis, IIT Delhi, 2016. http://localhost:8080/iit/handle/2074/7002.
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Van, der Horn Gert. "Integrated smart sensors calibration." Delft, Netherlands : Delft University Press, 1997. http://books.google.com/books?id=tHhRAAAAMAAJ.
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Ramesh, Prashanth. "Smart Materials for Electromagnetic and Optical Applications." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1343821988.
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Gent, Ian Oliver. "Biologically inspired adaptive camouflage : polychromatic smart materials." Thesis, University of Bristol, 2017. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.738293.
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Moss, Scott. "Modelling and experimental validation of the acoustic electric feedthrough technique." Fishermans Bend, Victoria : Defence Science and Technology Organisation, 2008. http://hdl.handle.net/1947/9738.
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Msomi, Velaphi. "Modelling and testing smart aileron servo tabs : developing simulation tools for smart materials." Thesis, Cape Peninsula University of Technology, 2015. http://hdl.handle.net/20.500.11838/2150.
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Thesis (DTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2015.This dissertation addresses the development and the testing of a simulation tool to be used to predict the behaviour of smart material/structures. Along with the development of the simulation tool, a new form of the model describing the behaviour of shape-memory alloy was developed and implemented. The proposed model was developed based on the existing cosine model, conventionally used in literature, but it uses hyperbolic tangent functions. The hyperbolic tangent function was chosen so as to allow the simulation of any range of temperatures. Experiments were performed to obtain the parameters to be used in the simulation and to validate the numerical results. Two different simulations were performed: a one dimensional FEA analysis with a two dimensional orientation (NiTi SMA wire simulation) and a three dimensional FEA analysis (NiTi SMA plate) [Msomi and Oliver, 2015]. Alongside the FEA analysis, two experiments were performed with the purpose of obtaining the material parameters to be used in FEA analysis and to compare the FEA results to the experimental results.
Airbus Company
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Akin, Tugce. "Communication Of Smart Materials: Bridging The Gap Between Material Innovation And Product Design." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12610999/index.pdf.
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This thesis is intended to help eliminate misconceptions and missing information
over the realm of smart materials, by offering a newly structured &lsquoInformation Hierarchy for Smart Materials Communication for Industrial / Product Design&rsquo
. Industrial and product designers are invited to use the findings of the thesis to assist in developing a common smart materials language and culture, enriched by details, technicalities, opportunities, and creative and innovative material attributes. The study commences with the creation of a concise and compact reservoir of technical knowledge on smart materials and critically contrasts two established systems of classification for smart materials. Then, the subject of materials information appropriate to industrial design is discussed, highlighting channels through which smart materials information may be communicated at an optimum level so as to be amenable to exploitation by industrial designers. A sectoral analysis of smart materials use follows, including the presentation of factors that may hinder their more extensive exploitation in major industrial sectors. v The thesis concludes that smart materials have potential to initiate a breakthrough in the materials universe, and that industrial designers have a role in promoting smart materials knowledge, the capabilities of smart materials, and their innovation possibilities. It is recomended that since smart materials are a new generation of materials quite different from the conventional, they be promoted carefully through the proposed Information Hierarchy.
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Prazzo, Carlos Eduardo [UNESP]. "Análise modal de uma estrutura do tipo viga utilizando materiais piezelétricos (PVDF) como sensores." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/94521.
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prazzo_ce_me_ilha.pdf: 1585012 bytes, checksum: 3ddb6b2bb4fddee99d49636888c24ded (MD5)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Esse trabalho discute o uso dos materiais piezelétricos, mais especificamente, o Polyvinylidene Fluoride (PVDF) e o Lead Zirconate Titatane (PZT) na análise modal experimental (AME) de estruturas mecânicas. Materiais piezelétricos, também chamados de materiais inteligentes, têm se consolidado como uma nova tecnologia que mostra um grande potencial de aplicação em diferentes áreas da engenharia. Esse tipo de material exibe um acoplamento entre multi-domínios físicos, como por exemplo o acoplamento eletro-mecânico, o térmo-magnético, etc. O acoplamento eletro-mecânico produz um deslocamento elétrico quando o material é sujeito a uma tensão mecânica (efeito direto) e um deformação mecânica quando esse material é submetido a um campo elétrico (efeito inverso). Assim, principalmente por conta desses efeitos, seu uso no campo da análise modal experimental torna-se uma interessante questão a ser investigada. A incorporação de novas tecnologias nos testes estruturais pode agregar novos conhecimentos e avanços tanto na análise modal baseada na relação entrada-saída da estrutura, quanto na mais recente técnica, a análise modal baseada apenas na resposta das mesmas. Os conceitos teóricos para o desenvolvimento são apresentados e discutidos neste trabalho, onde é mostrada a análise modal de uma viga utilizando tanto sensores e atuadores convencionais quanto os produzidos com materiais inteligentes. Os testes de análise modal da viga foram feitos utilizando diferentes combinações de sensores e atuadores e isso pode mostrar as diferenças da estimativa de modos utilizando materiais piezelétricos. Também é apresentada a formulação da relação entre os modos em deslocamento e os modos com diferença de inclinação obtidos com materiais piezelétricos e, finalmente, uma comparação dos resultados obtidos pelas diferentes técnicas. Os testes apresentados mostram...
This work discusses the use of piezoelectric materials, more specifically, Polyvinylidene Fluoride (PVDF) and Lead Zirconate Titanate (PZT) for experimental modal analysis (EMA) of mechanical structures. Piezoelectric materials also called smart materials have becoming a consolidated new technology that shows a large potential of application for different engineering areas. These materials exhibit a multi physics domain field coupling like mechanical and electrical coupling domains, thermal and magnetic coupling and etc. The electro-mechanical coupling domains of the material produces an electric displacement when the material is subject to a mechanical stress (direct-effect) and a mechanical strain when the material is submitted to an electric field (inverse effect). So, mainly due to these effects, the use in the experimental modal analysis field appears to be an interesting issue to be investigated. The incorporation of this new technology in the structural tests might aggregate new acknowledgments and advances in the well consolidated input-output based modal analysis techniques as well as in the more recent output only-based modal analysis. This work aims to present some contribution in this area by using piezoelectric sensors, instead of the conventional ones like accelerometers for modal analysis of mechanical structures. The theoretical concepts and background for the developing of the work are presented and discussed, it is also presented the modal analysis of a beam like structure using conventional sensors/actuators and piezoelectric materials. The modal analysis tests of the beam are conducted using different kinds of sensors/actuator and they give some insight of the difference of the estimated modes shapes by using piezoelectric materials. It is also presented a formulation that shows the relation between... (Complete abstract click electronic access below)
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Elshafei, Mostafa Adnan. "Smart composite plate shape control using piezoelectric materials." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1996. http://handle.dtic.mil/100.2/ADA320548.
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Dissertation (Ph.D. in Aeronautical and Astronautical Engineering) Naval Postgraduate School, September 1996.Dissertation supervisor(s): B.N. Agrawal. "September 1996." Includes bibliographical references (p. 111-118). Also available online.
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Bravo, Rafael. "Vibration control of flexible structures using smart materials." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0034/NQ66256.pdf.
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Vili, Yvonne Y. F. Chan. "Designing smart textiles based on shape memory materials." Thesis, Heriot-Watt University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.444799.
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Neqal, Mehdi. "Smart polymeric materials by ring-opening metathesis polymerization." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0658/document.
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Ce travail de thèse consiste à combattre le développement microbien des réservoirs de carburant aéronautiques dont le métabolisme entraine la production d’acides organiques susceptibles de corroder les parois métalliques des réservoirs. Des substances biocides sont habituellement utilisées pour éliminer les populations microbiennes. Ces substances peuvent être des composés organiques ou bien de manière plus courante du chrome (VI) sous forme de revêtement à la surface des parois afin de créer une couche passive et d’empêcher la corrosion chimique. Cependant, le chrome appartient à la catégorie des substances cancérogènes, mutagènes et reprotoxiques et se trouve maintenant soumis à restriction par la réglementation européenne Registration, Evaluation and Authorization of Chemicals (REACh). Pour remplacer les systèmes en place, le choix s’est porté sur la préparation de particules polymères pH-sensibles capables de libérer une molécule biocide en présence de microorganismes. De telles particules sont obtenues par copolymérisation par métathèse de cyclo-oléfines (ROMP) de norbornène avec un macromonomère linéaire de polyglycidol α-norbornenyl. Ce dernier permet d’une part la stabilisation des particules et d’autre part la multifonctionnalisation de l’objet par des molécules de biocide. Celles-ci sont introduites sur la chaîne de polyglycidol via un lien imine pH-sensible par substitution des fonctions hydroxyle par des entités dodécylamine. La libération du biocide à un pH inférieur à 7 a été validée ainsi que les capacités de ces particules à lutter contre des microorganismes tel que Hormoconis resinae souche identifiée comme se développant dans les réservoirs d’avions. Dans une dernière étape, les particules fonctionnalisées dodécylamine ont été incorporées dans un revêtement usuel en aéronautique et la capacité des particules à ne pas altérer la résistance du revêtement de base à des conditions de corrosion extrêmes a permis de vérifier leur applicabilité dans ce domaineThe aim of this Thesis work was to address the issue of microbial contamination inside fuel tanks. Microorganisms induce the chemical corrosion of airplane tank walls due to their production of organic acids. Biocide compounds are typically used to inhibit these microorganisms, either in the form of organic small molecules, or most commonly as chromium-based coatings on the walls to hinder chemical corrosion. Organic biocides need to be replenished regularly, while chromium is a particularly dangerous compound targeted by the European Registration, Evaluation and Authorization of Chemicals (REACh) legislation due to its carcinogenic nature. A replacement approach selected for this project was the development of a smart system of multifunctional polymeric particles synthesized by dispersion ROMP, which can deliver a biocide following an acidic trigger due to the presence of microorganisms. The polymerization utilized a linear α-norbornenyl-polyglycidol macromonomer as a reactive surfactant. The hydroxyl-rich polyglycidol backbone of the macromonomer was beneficial for the conjugation of dodecylamine through a pH-sensitive imine bond and permitted the preparation of highly functionalized bioactive particles. A proof of concept for the pH sensitivity of the system was provided and the antifungal efficacy of the biocide-functionalized macromonomer and particles was verified. The particles were also integrated in a coating formulation to simulate their application on tank walls. The qualities of the original coating were preserved even after prolonged exposure to corrosive conditions, making this system viable for its foreseen application
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Enemuoh, Emmanuel Ugochukwu. "Smart drilling of advanced fiber reinforced composite materials /." free to MU campus, to others for purchase, 2000. http://wwwlib.umi.com/cr/mo/fullcit?p9998482.
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Koen, Yolande. "Synthesis and investigation of smart nanoparticles." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/5356.
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Thesis (MSc (Chemistry and Polymer Science))--University of Stellenbosch, 2010.ENGLISH ABSTRACT: The use of various ‘smart materials’ (briefly meaning materials that respond to a change in their environment) is currently of interest to both academics and industry. The primary aim of the current study was to entrap photochromic (PC) dyes in miniemulsions, as a means to improve their fatigue resistance, thus synthesizing smart nanoparticles. In the coatings industry the use of aqueous systems is becoming a common requirement for health and environmental reasons. Miniemulsion entrapment allows the direct dispersion of PC dyes into aqueous systems while allowing for the opportunity to tailor-make the host matrix in order to obtain a suitable PC response and improved fatigue resistance. The optimal instrument set-up required to establish the PC response of films of the so-called smart nanoparticles (i.e. PC miniemulsions) was determined. A UV-Vis instrument with a chip-type UV LED mounted inside for activation of the samples provided PC response results. A tungsten lamp with filter provided deactivation of the samples. A stable butyl methacrylate (BMA) miniemulsion formulation was established by conducting a design of experiments. A chromene and spironapthoxazine (SNO) PC dye were entrapped in the BMA miniemulsion. A hindered amine light stabiliser (HALS) was also entrapped with the SNO dye in the BMA miniemulsion to further improve the fatigue resistance. The following PC properties of the smart nanoparticles films were evaluated: colourability, thermal decay rate, half-life and fatigue resistance. To compare results with conventional systems, a BMA solution polymer was prepared. The SNO dye and different concentrations of the HALS were mixed with the BMA solution polymer. In comparison to the SNO smart nanoparticles the chromene smart nanoparticles films had lower colourability, but better fatigue resistance. Incorporating HALS at levels of 0.5–2% in the BMA miniemulsion with PC dye did not lead to any significant improvement in fatigue resistance, yet films of the BMA solution polymer showed some improvement. SNO dye incorporated at 1% gave similar colourability in both miniemulsion and in solution polymer, yet the fatigue resistance of the films of the PC miniemulsions was much better.
AFRIKAANSE OPSOMMING: Die gebruik van verskeie “slim materiale’ (kortliks beskryf as materiale wat reageer op `n verandering in hul omgewing) is tans van belang vir beide akademici en die industrie. Die hoofdoel van hierdie studie was om miniemulsietegnologie te gebruik om fotochromiese (FC) kleurstowwe vas te vang, vir die sintese van slim nanopartikels, om sodoende die weerstand teen afgematheid te verbeter. In die verfindustrie word die gebruik van waterbasissisteme meer algemeen weens gesondheids- en omgewingsredes. Die gebruik van miniemulsie sisteme om materiale vas te vang maak dit moontlik om FC kleurstowwe direk in waterbasissisteme te meng. Die sintese van `n unieke gasheer matriks word benodig om die optimum FC verandering te toon en weerstand teen afgematheid te verbeter. Om die FC verandering van die sogenaamde slim nanopartikel films (d.w.s. FC miniemulsies) te ondersoek was `n gepaste instrumentele opstelling nodig. Dit is vasgestel dat `n UV-Vis instrument waarin `n skyfie-tipe UV LED gemonteer is vir aktivering van die monsters, reproduseerbare resultate gegee het. Die monsters is gedeaktiveer deur gebruik te maak van `n tungsten lig met ‘n filter. `n Eksperimentele ontwerp is toegepas om `n stabiele butielmetakrielaat (BMA) miniemulsie formulasie te verkry. `n ‘Chromene’ en ‘spironapthoxazine’ (SNO) FC kleurstof is in die BMA miniemulsie vasgevang tesame met `n verhinderde amien ligstabiliseerder (VALS) om die weerstand teen afgematheid verder te verbeter. Die volgende FC eienskappe van die slim nanopartikels is gemeet: kleurintensiteit, tempo van termiese verwering, half-lewe en weerstand teen afgematheid. `n BMA polimeeroplossing is berei om resultate mee te vergelyk. Die SNO kleurstof en verskillende konsentrasies van die VALS is met die BMA polimeeroplossing gemeng. In vergelyking met die slim SNO nanopartikels het die intelligente chromene nanopartikelfilms `n swakker kleurintensiteit gehad, maar `n hoër weerstand teen afgematheid. Die gebruik van 0.5–2% VALS in die BMA miniemulsie met FC kleurstof het minimale verbetering in weerstand teen afgematheid getoon, maar daar was wel `n beduidende verbetering in die geval van films met FC kleurstof in `n BMA polimeeroplossing. Byvoeging van 1% SNO kleurstof in `n BMA miniemulsie of polimeeroplossing het dieselfde kleurintensiteit gelewer, maar die weerstand teen afgematheid van die FC miniemulsie was baie beter.
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Tan, Khooi Yeei. "Smart surfaces using responsive polymer brushes." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.607743.
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Riddle, Brian K. "General purpose, data driven, extensible, computer interface for smart sensors." Thesis, Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/18920.
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Rodríguez, García Bárbara. "Prussian blue derivatives as smart materials for technological applications." Doctoral thesis, Universitat Rovira i Virgili, 2017. http://hdl.handle.net/10803/456996.
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Els hexacianometalats de metalls de transició, isoestructurals amb el blau de Prussia (PB), son un tipus molt important de composts de coordinació inorgànics. En general, son no estequioméstrics i de valència mixta, lo que els converteix en materials amb una química molt rica i versàtil i dels que se han descrit múltiples propietats i aplicacions. En aquesta tesi, explorem algunes modificacions d’aquests materials per abordar alguns reptes tecnològics.
En primer lloc, explorem la capacitat catalítica dels anàlegs de cobalt ferro (CoHFe) en la reacció d’oxidació d’aigua. Comprovem que, a més a més de ser actius i eficients en un interval ampli de pH, mantenien la seua capacitat catalítica estable en el temps, inclús en aigua de mar. A continuació, incorporem aquest catalitzador en dispositius. Por una banda, en el ànode d’un electrolitzador de membrana (PEM). Por l’altre, coneixent la estabilitat del CoHFe en aigua de mar, dissenyem i construïm un electrolitzador de agua de mar a escala de laboratori.
També sintetitzem un imant quiral a través de la incorporació d’un aminoàcid natural (L-prolina) en la síntesi de vanadio hexacianocromat (VHCr). Vàrem obtindre i caracteritzar una sèrie d’imants quirals amb magnetització espontània a temperatures crítiques altes, properes a temperatura ambient, i que no han segut reportades aabansntes.
Finalment, desenvolupem anàlegs del blau de Prussia de manganés-ferro (MnHFe) com a potencials agents de contrast multimodals. Segons la bibliografia, aquests anàlegs son agents de contrast no tòxics en ressonància magnètica nuclear i microscòpia òptica (generació de segon harmònic). Para ampliar aquestes capacitats, augmentem el seu coeficient d’extinció davant de la radiació de rais X incorporant cations alcalins en la seua estructura, i demostrem amb èxit que aquests materials atenuen els rais X millor que agents de contrast comercials per a tomografia.
En resum, hem demostrat que modificant els components de partida dels PBAs es poden modular les seues propietats. A més a més, la seua estructura robusta i la seua capacitat i facilitat per ser processats, obrin moltes oportunitats per futures aplicacions tecnològiques.Los hexacianometalatos de metales de transición, isoestructurales al azul de Prussia (PB), son un tipo muy importante de compuestos de coordinación inorgánicos. En general, son no estequiométricos y de valencia mixta, lo que les convierte en materiales con una química muy rica y versátil y de los que se han descrito múltiples propiedades y aplicaciones. En esta tesis, exploramos algunas modificaciones de estos materiales para abordar algunos retos tecnológicos. En primer lugar, exploramos la capacidad catalítica de los análogos de cobalto hierro (CoHFe) en la reacción de oxidación de agua. Comprobamos que, además de ser activos y eficientes en un amplio rango de pH, mantenían su capacidad catalítica estable en el tiempo, incluso en agua de mar. A continuación, incorporamos este catalizador en dispositivos. Por un lado, en el ánodo de un electrolizador de membrana (PEM). Por el otro, conociendo la estabilidad del CoHFe en agua de mar, diseñamos y construimos un electrolizador de agua de mar operativo a escala de laboratorio. También sintetizamos un imán quiral a través de la incorporación de un aminoácido natural (L-prolina) en la síntesis de vanadio hexacianocromato (VHCr). Obtuvimos y caracterizamos una serie de imanes quirales que exhiben magnetización espontanea a temperaturas críticas altas, cercanas a temperatura ambiente, y que no han sido reportadas antes. Finalmente, desarrollamos análogos del azul de Prusia de manganeso-hierro (MnHFe) como potenciales agentes de contraste multimodales. Según la bibliografía estos análogos son potenciales agentes de contraste no tóxicos en resonancia magnética nuclear y microscopía óptica (generación de segundo armónico). Para ampliar estas capacidades, aumentamos su coeficiente de extinción frente a la irradiación de rayos X incorporando cationes alcalinos en su estructura y demostramos con éxito que estos materiales atenúan los rayos X en mayor medida que los agentes de contraste para tomografía comerciales. En resumen, hemos demostrado que modificando los componentes de partida de los PBAs se pueden modular sus propiedades. Además, su estructura robusta y su capacidad y facilidad para ser procesados, mantienen abiertas múltiples oportunidades para aplicaciones tecnológicas futuras.
Transition metal hexacyanometallates are an important class of inorganic coordination compounds, isostructural with the original mixed-valence Prussian blue (PB). Their non-stoichiometric nature and chemical variety make of them a versatile type of molecule-based materials. Indeed, a wide range of applications has been described. In this thesis, we explored further applications for Prussian blue analogues, modifying their composition and processing to target several technological issues. First, the catalytic performance of cobalt iron Prussian blue analogues (CoHFe) to promote oxygen evolution reaction in a water splitting was tested. Catalyst nanoparticles were active and efficient in a wide pH range and is stable and functional in the long run even in sea water. Then we incorporate this catalyst in full-cell devices. On one hand, we built and tested a polymer electrolyte membrane (PEM) containing CoHFe as water oxidation electrocatalyst. On the other, we took advantage of CoHFe stability in sea water for the design and construction of a lab scale seawater electrolyzer. We also report our aims to obtain a chiral magnet. Through incorporation of a natural aminoacid (L-proline) in the synthesis of the vanadium-chromium Prussian blue analogues (VHCr), we were able to obtain, and characterize chiral magnets that exhibit spontaneous magnetization at the highest temperatures ever reported, and close to room temperature. Finally, we present our studies for the development of manganese iron Prussian blue analogues (MnHFe) as multimodal contrast agent. These derivatives are potential non-toxic contrast agents nuclear magnetic resonance and optical microscopy (second harmony generation) diagnosis techniques. To expand their multimodal features, we increase their extinction coefficient versus x-ray irradiation by incorporated alkaline metal cations to their structure. We successfully demonstrate that these materials show x-ray attenuation capabilities superior to state-of-the-art commercial tomography contrast agents. In summary, we have demonstrated the versatility of PBAs for multiple applications by modifying building blocks and components. The robustness of the structure, and the multiple redox/composition/processing parameters maintain open unlimited opportunities for potential technological applications.
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Brufau, Penella Jordi. "Smart materials for microrobotics motion control and power harvesting." Doctoral thesis, Universitat de Barcelona, 2009. http://hdl.handle.net/10803/1512.
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This thesis focuses on the use of smart materials in microrobotic applications. The development of materials with the capabilities to mechanically respond to electrical stimuli or, at the same time, to electrically respond to mechanical stimuli, has entailed the microrobotics rapid evolution. Along this thesis the use of three smart materials families in the filed of microrobotics is studied. The materials used are the piezoelectric ceramics, the piezoelectric polymers and the ionic polymers metal composites IPMC. The similitude in the way they respond to external stimuli has motivated this study. The three materials respond with an induced mechanical strain under the application of an electric field and respond with an induced electrical charge variation when a mechanical pressure is applied. Although these materials respond similarly, their application in microrobotic systems entails different problems. In this thesis their use in different applications is studied and the problems enclosed with their use are treated. First of all in this thesis the use of piezoelectric polymers and ionic polymers as materials for motion control of microrobots is studied. Their flexibility opens the door to new applications for microrobot systems as is the case of biomimetics. The first application regards the use of piezoelectric polymers in insect-like mm3 microrobot. The microrobot is composed with three legs and one antenna or tool for object collision based on piezoelectric polymers. The object collision tool is used as a sensor for motion control to avoid collisions with other objects. The work presented consists on the development of theoretical models to predict the motion of he leg and the tool of the microrobot. The second application regards the development of a control system for controlling the motion of an ionic polymer IPMC underwater. It is difficult to obtain physical models that describe the motion of these materials, thus it is important to design control strategy to work with IPMCs. Furthermore in this thesis, the problem of manufacturing electrodes for IPMC is also treated.
In the second part of the thesis the use of piezoelectric ceramics to harvest power from mechanical vibrations is studied. Piezoelectric ceramics have higher energy densities compared with other methods for power harvesting from vibrations. In comparison with the piezoelectric polymers, the piezoelectric ceramics produce voltages and current levels more acceptable. From the study performed in this thesis the conditions for a maximum power generation are obtained and an optimum electronic circuit for energy storage and management is designed. At the end of the thesis the capabilities to harvest power using ionic polymers are studied.
KEY WORDS: Smart Materials, Microrobotic, Harvesting, Motion Control, Fonic Polimer, FPMC Piezoelectric, Modelling
Aquesta tesis es centra en l'ús de materials "smart" o intel·ligents en aplicacions de microrobòtica. Al llarg de la tesi treballem amb tres famílies de materials "smart" diferents: les ceràmiques piezoelèctriques, els polímers piezoelèctrics i els polímers iònics coneguts com Ionic Polymer Metal Composites (IPMC). Aquests materials tenen en comú que al aplica'ls-hi un camp elèctric pateixen una deformació mecànica mentre que si els sotmetem a una deformació mecànica, aquests materials pateixen una variació en la seva càrrega elèctrica interna. Degut a aquestes propietats aquests materials poden ser utilitzats com a sensors o com a actuadors.
A la primera part de la tesi estudiem l'ús dels polímers piezoelèctrics i dels polímers iònics per al control del moviment dels microrobots. La primera aplicació que es presenta tracta d'un microrobot de dimensions mm3 que utilitza els polímers piezoelèctrics com a potes i com a sensors de col·lisió. Tot seguit presentem una aplicació a on els IPMCs són utilitzats com a microposicionadors treballant sota de l'aigua.
A la segona part de la tesis estudiem la viabilitat d'utilitzar les ceràmiques piezoelèctriques i els polímers iònics per a generar energia a partir de vibracions mecàniques residuals ambientals. L'estudi presentat determina els nivells de potència generats i les condicions òptimes per a la generació de la màxima potencia.
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Palmer, Nathan Reed. "Smart Composites evaluation of embedded sensors in composite materials /." Thesis, Montana State University, 2009. http://etd.lib.montana.edu/etd/2009/palmer/PalmerN0809.pdf.
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As an emerging form of renewable energy, horizontal wind turbines have experienced advancements in improving efficiency and reliability. These advances have pushed the limits of current technology used in wind turbines. Smart blades have been proposed as a method of addressing these limitations. Sensor integration within blade construction is the first step in development of smart blades. Thus, several low cost sensors were chosen, 1 axis strain gages, polyvinylidene fluoride films (PVDF), and single mode fiber optics either coated in acrylate or polyimide. To ensure successful bonding between sensor and composite two surface treatment techniques were developed. The first, dipping of the sensor into a bath of 20% by weight solution of nitric acid and the second was submersion of the sensor in the nitric acid for ten seconds prior to removal. These treatments were compared against sensors not surface treated prior to embedding. These sensors were embedded within samples created of fiberglass and epoxy or vinyl ester resin. Two different material tests were conducted. Tensile testing allowed for evaluation of sensor sensitivity, sensor failure point, material tensile modulus, and material tensile strength. Mode I fracture toughness evaluation, indicated the level of successful bonding which occurred during resin curing. Field Emission Scanning Electron Microscopy (FESEM) was conducted to further confirm the level of bonding between resin and sensor, post fracture. Results for embedded strain gages showed an adverse effect for vinyl ester samples. Epoxy samples fared better, thus concluding manufacturing success for epoxy samples, submersion being preferred, and alternative methods needed for vinyl ester samples. PVDF films had good qualitative FESEM images combined with increasing trends. It was concluded that integration for both resin groups with sensors submerged in nitric acid was successful. Fiber optics coated in acrylate also showed good bonding under FESEM imaging as well as testing. It was thus concluded that submersion was the preferred treatment. Lastly, fiber optics coated in polyimide embedded in vinyl ester composites showed significant drawbacks and it was concluded that alternative methods need exploration. Those embedded in epoxy were successfully integrated and submersion in nitric acid showed the most potential.
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Ledendal, Marie. "Chromatic chlorophyll : Conceptual hospital textiles with chromatic Smart Materials." Thesis, Högskolan i Borås, Institutionen Textilhögskolan, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-19626.
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THIS PROJECT AIMS TO look at how Smart Textiles can change today’s view and useof the interiors of the healthcare environment, through conceptual examples of the usabilityof the Photochromics and Thermochromics working as an information bridge for moreisolated patients. The thesis has a practical experimental approach and points out some of thechromatic materials possibilities in relation to present research of the two chromatic materials.The thesis discusses the relation between healing environment and the importance of aesthetics,with a purpose to meet Emotional and Social needs of feeling “alive”, “well” and“included”. Research indicate that nature has a calming affect on patients, therefore flowersand leaves have been inspiration for the expression of the textiles. The colour changecreates a subtle communicative bridge between patient and movement in the hospital - “theRhythm of the House” and the outdoor -“the Rhythm of the Sun”. The conceptual proposalpresents a design solution where the colour changeability stands for a communicativelevel, as well as a decorative and a dynamic level. The textile samples communicate thevisual and hepatic expression, as well as the integration of the electronics. The scenariofor the thesis is set to the 2015-20, due to reasonability for Smart Textiles to be developedto be used as interior textile products for the healthcare environment.
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Orth, Margaret A. (Margaret Ann) 1964. "Sculptured computational objects with smart and active computing materials." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/8674.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2001.Includes bibliographical references (leaves 325-328).
This thesis presents the creative, technological, and philosophical means and methodology, by which technology artists and researchers can materially and sculpturally transform physical computing technology from hard, remotely-designed, plastic shells, into intimately created, sensual computing objects and artifacts. It asserts that the rigid, square, and prefabricated physical materials of computing technology are a fundamental technological and artistic limitation to anyone who wishes to sensually transform physical computing technology, or develop a rich artistic vocabulary for it. Smart and active sculptural computing materials are presented as a solution to this problem. Practically, smart computing materials reduce the number of separate, rigid, and square prefabricated parts required to create physical computing objects. Artistically, active sculptural computing materials give artists and designers the ability to directly manipulate, shape, experiment with, and therefore aesthetically understand the real, physical materials of computing technology. Such active design materials will also enable creative people to develop a meaningful artistic relationship between physical form and computation. The total contributions of this thesis include a proposal for a future three-dimensional design/technology practice, a portfolio of sensually transformed expressive computational objects (including new physical interfaces, electronic fashions, and embroidered musical instruments), and the smart and active sculptural computing materials and processes (in this case smart textiles), which make that transformation possible. Projects from the design portfolio include: The Triangles, and its applications; Electronic Fashions, including the Firefly Dress and Necklace, New Year's Eve Ball Gown, and Serial Suit; The Musical Jacket; Electronic Tablecloths; and a series of Embroidered Musical Instruments with embroidered pressure sensors. Contributions from the supporting technical area include: the first fabric keypad (a row and column switch matrix), a new conductive yarn capable of tying and electrical/mechanical knot, an advanced process for machine embroidering highly conductive, flexible and visually diverse electrodes, an empirical model of complex impedance sensing, and a definition of and test for the machine sewability and flexibility of yarns. These contributions are presented in three sections: 1) the supporting arguments, and philosophy of materiality and computation behind this work, 2) the design portfolio, and 3) the supporting technical story.
by Margaret A. Orth.
Ph.D.
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Turkmen, Serkan. "Application of smart materials for vibration reduction in ships." Thesis, University of Strathclyde, 2013. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=23159.
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Smart Materials have been investigated for decades and widely used in the automotive and aeronautics industries to measure and control noise and vibration. This study covered ship structure vibration and Smart Materials were employed for the purpose of ship vibration attenuation. One specific Smart Material, piezoelectric material, was the focus of the study. Although previous research has been conducted on vibration mitigation employing piezoelectric shunt systems, this study identified the need for specific applications regarding ship vibration mitigation. Passive piezoelectric shunt damping systems for ships were described and investigated in this study. Computational methods were used to investigate structural vibration of a cantilever beam, a Liquid Natural Gas (LNG) carrier and a bulb keel. The Finite Element Method (FEM) was used to calculate the vibration and vibration treatment with the passive piezoelectric shunt damping system. The numerical results of the passive piezoelectric shunt system bonded to the cantilever beam were compared to experimental results obtained from a previous study. The FEM delivered results, which showed a high degree of similarity in comparison to the experimental results. Both experimental and numerical studies validate the theory that piezoelectric material, connected to an electrical circuit, can be successfully used to achieve vibration reduction. Significant vibration attenuation was found in the numerical simulation of the LNG vessel. The simulation of the bulb keel also provided promising outcome regarding substantial vibration reduction by means of piezoelectric shunt system.
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Liu, Mengmeng. "Self-assembled Photo-responsive Nanostructures for Smart Materials Applications." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1494160345663184.
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Matsouka, Dimitroula. "Efficiency and durability of wearable smart materials and structures." Thesis, University of Bolton, 2018. http://ubir.bolton.ac.uk/1767/.
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Piezoelectric polymer materials have been under investigation since the 1970’s starting with the discovery of the piezoelectric effect in PVDF films by Kawai. Since then the piezoelectric effect has been detected among other polymers in polyureas, polyamides, and polypropylene and their copolymers. While the investigation of the piezoelectric effect was largely carried out on the film form of the polymers since 2010 interest has developed into the production methods, properties and applicability of melt spun piezoelectric textile fibres made of these polymers. The application of piezoelectric fibres could have a significant impact in wearable textiles as sensors, actuators, or energy harvesting modules. Current research is mostly centred onto production methods and fibre crystallinity characterization. The research carried out in this PhD by publication project is concerned with piezoelectric textile fibres as electrically active elements. As such the research focused on the electrical behaviour of the fibres. The work carried out was threefold. Specifically, wearable textile materials undergo cleaning/ care treatments that are intrinsic to their function as wearables. These treatments may include washing, dry cleaning or sponging. Washing (cleaning treatment in a solution mainly containing water and an appropriate detergent at an elevated temperature or room temperature) is a common cleaning method. The effects of washing cycles on melt spun piezoelectric fibres remain under-investigated. For the first part of the research, piezoelectric melt spun fibres (PVDF, PP and PA-11) with two different cross sections (circular and rectangular), were mechanically stimulated by a rotating fin that impacted the fibres periodically. The resulting Vp-p (peek to peek voltage), was measured on the original fibres and on the fibres following one wash cycle (adapted BS EN ISO 105-C06), using an oscilloscope. Based on the results of this part of the research it was shown that the washing cycle effected the voltage response of the fibres depending on the fibre cross section and the fibre composition. The results of the research were presented in a paper titled “Investigation of the durability and stability of piezoelectric textile fibres” published in the Journal of Intelligent Materials Systems and Structures. For the second part of the research, it was noted that according to the existing literature the research approach for the determination of the electrical response of the fibres utilized exclusively the measurement of the voltage produced by mechanical excitation of the fibres, in open circuit conditions. This approach is not sufficient to satisfactorily characterise the electrical behaviour of the fibres as power generating elements. By contrast, a sufficient measurement is the power production of the fibres as this also includes a measurement of the current produced. In order to supply these measurements a testing apparatus/ methodology was developed. The apparatus consists of a measuring station where the voltage and current produced are measured, and a means for periodic mechanical stimulation of the specimens. The equipment was used to determine the power generated by piezoelectric melt spun fibres (PVDF, PP and PA-11) with two different cross sections (circular and rectangular). The results of the research were presented in a paper titled “On the Measurement of the Electrical Power Produced by Melt Spun Piezoelectric Textile Fibres” published in the Journal of Electronic Materials. Finally, considering the underlying premise of integration of fully textile based electronic components into textile substrates (e.g. wearable applications), 3D knitted fabrics that incorporated piezoelectric melt spun fibres were investigated with regards to their capacitive behaviour. Four different fabric structures were examined (different composition of the outside layers and different thickness). The capacitive behaviour of the samples was modelled based on the specific structural characteristics of the fabrics and the actual properties were determined using an Impedance Analyzer. Based on the results it was found that the theoretical model for the calculation of the capacitance of the samples appeared to be an acceptable approximation for the behaviour of the fabrics. Also, the ability to customise the required capacitance to suit the applications by specifying the dimensions of the 3D fabric and/or the density, the thickness or even the material of the interlaced fibres has also been shown to be possible. Moreover, reviewing the results of a resonance test for a purely textile based parallel LC circuit, it was shown that it is possible to implement resonant circuits that are convenient for basic electronic applications (i.e. oscillators, filters, etc.). The results of the research were presented in a paper titled “Three-dimensional weft-knitted textile fabrics-based capacitors” published in the Journal of the Textile Institute. This research project touched on some of the less thoroughly investigated research areas connected to the efficiency and durability of piezoelectric melt spun fibres and structures, with innovative results such as the development/ construction of the equipment that can be used for the measurement of the power produced by piezoelectric textile fibres as well as the investigation of the capacitive behaviour of the 3D knitted fabrics incorporating piezoelectric textile fibres and the conclusion that resonance is possible to achieve in a purely textile LC parallel circuit.
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Gino, Maria Elena <1990>. "Nanostructured smart materials as functional components of medical devices." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2022. http://amsdottorato.unibo.it/10439/3/Tesi_Maria%20Elena%20Gino.pdf.
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The field of medical devices has experienced, more than others, technological advances, developments and innovations, thanks to the rapidly expanding scientific knowledge and collaboration between different disciplines such as biology, engineering and materials science.
The design of functional components can be achieved by exploiting composite materials based on nanostructured smart materials, that due to the inherent characteristics of single constituents develop unique properties that make them suitable for different applications preserving excellent mechanical proprieties. For instance, recent developments have focused on the fabrication of piezoelectric devices with multiple biomedical functions, as actuation and sensing functions in one component for monitoring pressure signals.
The present Ph.D. Thesis aims at investigating nanostructured smart materials embedded into a polymeric matrix to obtain a composite material that can be used as a functional component for medical devices. (i) Nanostructured piezoelectric material with self-sensing capability was successfully manufactured by using ceramic (i.e. lead zirconate titanate (PZT)) and (ii) polymeric (i.e. poly(vinylidene fluoride-trifluoro ethylene (PVDF-TRFE)) piezoelectric materials.
PZT nanofibers were obtained by sol-gel electrospinning starting from synthetized PZT precursor solution. Synthesis, sol-gel electrospinning process, and thermal treatment were accurately controlled to obtain PZT nanofibers dimensionally stable with densely packed grains in the perovskite phase. To guarantee the impact resistance of the laminate, the morphology and size of the hosting filler were accurately designed by increasing the surface area to volume ratio.
Moreover, to solve the issue relative to the mechanical discrepancy between rigid electronic materials/soft human tissues/different material of the device (iii) a nanostructured flexible composite material based on a network of Poly-L-lactic acid (PLLA) made of curled nanofibers that present a tuneable mechanical response as a function of the applied stress was successful fabricated.
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BELLACICCA, ANDREA. "SMART MATERIALS FOR STRETCHABLE ELECTRONICS, SENSORS AND SOFT ACTUATION." Doctoral thesis, Università degli Studi di Milano, 2017. http://hdl.handle.net/2434/476724.
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Smart materials can be exploited to facilitate disruptive or transformative changes in several fields like stretchable electronics, soft robotics or to develop new class of sensors. They are innovative materials that interact with the environment and respond to external stimuli altering their physical properties in a controlled fashion. They are made integrating different materials at the nanoscale in a nanocomposite to obtain novel functionalities that are not showed from individual constituents.
Polymers are the best candidates to be used in smart material fabrication because of their structural and functional properties that can be easily tuned. Moreover, they are low-cost, versatile and can be processed into any shape including thin films. In order to exploit smart materials for soft robotics or stretchable electronic applications, it is required that they should be electrically conductive, patternable, have good mechanical properties and need to be able to transduce an electrical signal in a mechanical response. In addition, their functionalities should remain unchanged over a long period of time. Thus polymers are combined with hard materials like metals, semiconductors or standard electronic components.
It is challenging to fabricate technologically relevant smart materials combining hard and soft materials because of their intrinsic physical diversities. Standard manufacturing processes fail to achieve the needed requirements.
Among different processes to fabricate smart materials based on polymers, Supersonic Cluster Beam Implantation (SCBI) and Supersonic Cluster Beam Deposition (SCBD) are effective techniques to realize smart materials based on metal/polymer nanocomposites. In my thesis work, I have demonstrated that it is possible to produce new robust smart materials, designing both their electrical and mechanical properties with sharp precision. Metal/polymer nanocomposites have been designed at the nanoscale level to obtain sensors, actuators and electronic devices. Their electrical and mechanical properties have been characterized and their performances have been tested under different stress conditions.
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Prazzo, Carlos Eduardo. "Análise modal de uma estrutura do tipo viga utilizando materiais piezelétricos (PVDF) como sensores /." Ilha Solteira : [s.n.], 2011. http://hdl.handle.net/11449/94521.
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Orientador: João Antonio PereiraBanca: Luiz de Paula do Nascimento
Banca: Roberto Gil Annes da Silva
Resumo: Esse trabalho discute o uso dos materiais piezelétricos, mais especificamente, o Polyvinylidene Fluoride (PVDF) e o Lead Zirconate Titatane (PZT) na análise modal experimental (AME) de estruturas mecânicas. Materiais piezelétricos, também chamados de materiais inteligentes, têm se consolidado como uma nova tecnologia que mostra um grande potencial de aplicação em diferentes áreas da engenharia. Esse tipo de material exibe um acoplamento entre multi-domínios físicos, como por exemplo o acoplamento eletro-mecânico, o térmo-magnético, etc. O acoplamento eletro-mecânico produz um deslocamento elétrico quando o material é sujeito a uma tensão mecânica (efeito direto) e um deformação mecânica quando esse material é submetido a um campo elétrico (efeito inverso). Assim, principalmente por conta desses efeitos, seu uso no campo da análise modal experimental torna-se uma interessante questão a ser investigada. A incorporação de novas tecnologias nos testes estruturais pode agregar novos conhecimentos e avanços tanto na análise modal baseada na relação entrada-saída da estrutura, quanto na mais recente técnica, a análise modal baseada apenas na resposta das mesmas. Os conceitos teóricos para o desenvolvimento são apresentados e discutidos neste trabalho, onde é mostrada a análise modal de uma viga utilizando tanto sensores e atuadores convencionais quanto os produzidos com materiais inteligentes. Os testes de análise modal da viga foram feitos utilizando diferentes combinações de sensores e atuadores e isso pode mostrar as diferenças da estimativa de modos utilizando materiais piezelétricos. Também é apresentada a formulação da relação entre os modos em deslocamento e os modos com diferença de inclinação obtidos com materiais piezelétricos e, finalmente, uma comparação dos resultados obtidos pelas diferentes técnicas. Os testes apresentados mostram... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: This work discusses the use of piezoelectric materials, more specifically, Polyvinylidene Fluoride (PVDF) and Lead Zirconate Titanate (PZT) for experimental modal analysis (EMA) of mechanical structures. Piezoelectric materials also called smart materials have becoming a consolidated new technology that shows a large potential of application for different engineering areas. These materials exhibit a multi physics domain field coupling like mechanical and electrical coupling domains, thermal and magnetic coupling and etc. The electro-mechanical coupling domains of the material produces an electric displacement when the material is subject to a mechanical stress (direct-effect) and a mechanical strain when the material is submitted to an electric field (inverse effect). So, mainly due to these effects, the use in the experimental modal analysis field appears to be an interesting issue to be investigated. The incorporation of this new technology in the structural tests might aggregate new acknowledgments and advances in the well consolidated input-output based modal analysis techniques as well as in the more recent output only-based modal analysis. This work aims to present some contribution in this area by using piezoelectric sensors, instead of the conventional ones like accelerometers for modal analysis of mechanical structures. The theoretical concepts and background for the developing of the work are presented and discussed, it is also presented the modal analysis of a beam like structure using conventional sensors/actuators and piezoelectric materials. The modal analysis tests of the beam are conducted using different kinds of sensors/actuator and they give some insight of the difference of the estimated modes shapes by using piezoelectric materials. It is also presented a formulation that shows the relation between... (Complete abstract click electronic access below)
Mestre
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Gummadi, Lakshmana Nagesh Babu. "Active control of delaminations in smart composite structures." Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/13022.
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Hota, Sandilya. "Development and evaluation of smart materials for structural health monitoring." Morgantown, W. Va. : [West Virginia University Libraries], 2006. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=4470.
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Thesis (M.S.)--West Virginia University, 2006.Title from document title page. Document formatted into pages; contains xi, 87 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 86-87).
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Biehlig, Ekaterina. "Design of Smart Polymeric Materials with Responsive / Adaptive Adhesion Properties." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-118293.
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Adhesion between different objects is happening everywhere. Without it, simple procedures like walking or holding something in a hand or attaching a postage stamp would be impossible. The life itself depends on adhesion on all levels, starting from the interactions between the living cells.
Adhesion between two substrates is a complex phenomenon, which at present is still not well understood. There are several factors determining the strength of adhesion: (i) molecular interactions at interface, (ii) mechanical properties of adhesive, and (iii) area of contact between adhesive and probing surface. Two surfaces are tacky when they possess the right balance between these factors.
Controlling the adhesion of materials is important in many fields ranging from industrial purposes to biomedical applications and everyday usage. There is a demand for “smart” materials with integrated functionalities that make them responsive, switchable, biocompatible, anti-bacterial, more energy efficient, or autonomous. In particular, materials for such cutting-edge applications like cell culture, drug delivery, tissue engineering, biosensors, anti/biofouling, microfluidics, climbing robots, sport equipment and many others require adjustable/tuneable adhesive properties.
Many efforts were directed towards fabrication of materials with either weak or strong adhesion depending on the field of application. However, design of “smart” surfaces with reversibly switchable/controllable adhesion is still a highly challenging task.
Therefore, the thesis aims on design of smart polymeric materials with responsive / adaptive adhesion properties. For this, fabrication and investigation of two types of switchable polymer layers based on stimuli-responsive polymer brushes will be performed. The first group is dealing with thermoresponsive polymer brushes: poly-(N-isopropylacrylamide) and two types of biocompatible polyethylene glycol-based systems. These polymer layers undergo phase transition below and above LCST between hydrophilic and hydrophobic states. The second part of the work is related to solvent-responsive comb-like and block copolymer brushes consisted of hydrophilic PEG and hydrophobic PDMS biocompatible and biodegradable polymers.
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Lobez, Comeras Jose Miguel. "New functional polymers for sensors, smart materials and solar cells." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/73367.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2012.Vita. Cataloged from PDF version of thesis.
Includes bibliographical references.
Organic polymers can be used as the active component of sensors, smart materials, chemical-delivery systems and the active layer of solar cells. The rational design and modification of the chemical structure of polymers has enabled control over their properties and morphology, leading to the advancement of nanotechnology. A deeper understanding of structure-property relationships, as described in this thesis, affords control over the nanostructure of devices made from these macromolecular materials, which is crucial to the optimization of their performance. In Chapter 1, a new sensor for ionizing radiation based on composites of electron beam lithography resists, poly (olefin sulfone)s (POSs), and multiwalled carbon nanotubes is presented. The polymeric active component is radiation labile and its degradation after a sensing event leads to morphological and electrical changes in the composite at the nanoscale. As a result, a signal can be detected. Systematic sensitivity improvements can be accomplished by rational modifications of the chemical structure of the polymer side-chains. Orthogonal postpolymerization modifications performed using "click" chemistry, incorporate functional groups capable of increasing either the homogeneity of the composite, or its opacity towards radiation. In Chapter 2, a smart hybrid polymer composed of a POS and a silicone linked by "click" chemistry is described. By tuning the chemical structure of these two components and varying their ratio, composites with different mechanical properties and hardness can be achieved. This elastomeric smart material exhibits switchable mechanical properties: exposure to mild bases triggers disassembly into its monomers and individual constituents. In Chapter 3, the design, synthesis and properties of new polymer surfactant additives for photovoltaic devices is shown. The AB alternating regioregular polythiophene copolymer additives are obtained via a combinatorial approach, and contain functional groups in every other repeat unit. In Chapter 4 incorporation of small amounts of these polymer additives (0.25 weight %) is shown to result in large increases of up to 30% in the power conversion efficiency of organic solar cells consisting primarily of the benchmark system of poly (3-hexylthiophene) and Phenyl-C6 1-butyric acid methyl ester (PCBM) as the active layer. This effect is mainly due to the presence of dipoles at the interface of the bulk heterojunction introduced by the additives, which prevent charge recombination and lead to increases in the photocurrent collected across the polymer-fullerene interface. In Chapter 5, the synthesis of liquid crystalline polymer brushes is described, and their supramolecular and self-assembly properties are studied. The solid-state ordering and alignment properties of these highly substituted polymers can be affected by chemically tuning their mesogenic oligomeric side-chains, the length of the polymer backbone and the degree of crosslinking. The morphologies obtained with these macromolecules are interesting from the point of view of future photovoltaic applications.
by Jose Miguel Lobez Comeras.
Ph.D.
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Berglin, Lena. "Interactive Textile Structures : Creating Multifunctional Textiles based on Smart Materials." Doctoral thesis, Högskolan i Borås, Institutionen Textilhögskolan, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-3490.
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Textiles of today are materials with applications in almost all our activities. We wear clothes all the time and we are surrounded with textiles in almost all our environments. The integration of multifunctional values in such a common material has become a special area of interest in recent years. Smart Textile represents the next generation of textiles anticipated for use in several fashion, furnishing and technical textile applications. The term smart is used to refer to materials that sense and respond in a pre-defined manner to environmental stimuli. The degree of smartness varies and it is possible to enhance the intelligence further by combining these materials with a controlling unit, for example a microprocessor. As an interdisciplinary area Smart Textile includes design spaces from several areas; the textile design space, the information technology design space and the design space of material science. This thesis addresses how Smart Textiles affect the textile design space; how the introduction of smart materials and information technology affects the creation of future textile products. The aim is to explore the convergence between textiles, smart materials and information technology and to contribute to providing a basis for future research in this area. The research method is based on a series of interlinked experiments designed through the research questions and the research objects. The experiments are separated into two different sections: interactive textile structures and health monitoring. The result is a series of basic methods for how interactive textile structures are created and a general system for health monitoring. Furthermore the result consists of a new design space, advanced textile design. In advanced textile design the focus is set on the relation between the different natures of a textile object: its physical structure and its structure in the context of design and use.
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Cremin, Neal. "Asymmetric synthesis of liquid crystalline materials and chiral smart moelcules." Thesis, Kingston University, 2001. http://eprints.kingston.ac.uk/20675/.
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The synthesis and investigation of a series of bichromophoric molecules, based upon 7-methylene-cis-bicyclo[3.3.0]octan-3-ones, which exhibit optical dissymmetry, have been investigated for use as liquid-crystal-based chiroptical switches. Doping of these optically active materials into nematic liquid crystals (LC's) induced a cholesteric phase. The handedness of the dopant controls the direction and magnitude of the helical twist in the cholesteric phase. Irradiation of these matrices with circularly polarised light leads to reversible photoswitching processes which, induce an enantiomeric excess of one stereoisomer, and either a left or right handed helix is generated. These mirror image isomers represent the 1 and O states of binary logic. Such systems have potential applications in three-dimensional memory storage devices. Selective excitation of these bichromophoric molecules at 305nm leads to an intra-molecular energy transfer from the donor keto chromophore to the exocyclic double bond at the opposite end of the rigid bicyclo[3.3.0]octane spacer. We have investigated the extent of the achievable photoresolution and observed the magnitude of the helical pitch that can be induced in the nematogen PCB -7. Seven novel trigger groups were synthesised and their properties investigated; (i) Hanessian non-ester moieties, (ii) Mosher esters, (iii) aliphatic esters, (iv) propargyl ester, (v) biphenyl ester, (vi) alkyl, biphenol and polyfluoro esters, and (vii) PCH-7 ester. Their synthesis involved Wittig type chemistry to add the exocyclic alkene-groups. Enantiomeric excesses were determined by capillary electrophoresis. Kuhn dissymmetry factors (gA.) were determined, using UV and CD spectroscopy, and helical twisting powers (ßm), by the droplet method. Group (i) triggers were initially investigated but our model studies suggested that the synthesis of a library of molecules based on this synthetic route would be problematic. Group (iii) esters displayed lower dissymmetry then their parent acid and required to be doped in too high a concentration, compromising the integrity of the LC host. Group (vi) showed excessive overlap of the n-n* band destroying dissymmetry but displayed a potential for LC formation. In contrast groups (ii), (iv) and (vii) possessed useful molecular properties making them useful as molecular switches.
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Vones, Katharina Bianca. "Towards the uncanny object : creating interactive craft with smart materials." Thesis, University of Dundee, 2017. https://discovery.dundee.ac.uk/en/studentTheses/2d9a7303-4fd7-4110-ae83-6438904108a5.
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The increasing prevalence of digital fabrication technologies and the emergence of a novel materiality in contemporary craft practice have created the need to redefine the critical context of digital jewellery and wearable futures. Previous research in this area, such as that presented by Sarah Kettley (2007a) and Jayne Wallace (2007), has provided the foundations for further enquiry but has not been advanced significantly since its inception. The artistic research presented in this thesis focuses on how smart materials and microelectronic components could be used to create synergetic digital jewellery objects and wearable futures that reflect changes in the body of their wearer and their environment through dynamic responses. Laying the foundations for a theory of Interactive Craft through evaluating different aspects of creative practice that relate to responsive objects with a close relationship to the human body is at the centre of this enquiry. Through identifying four distinct categories of wearable object, the Taxonomy of the Wearable Object is formulated and clearly delineates the current existing conceptual, technological and material perspectives that govern the relationships between different types of wearable objects. A particular focus is placed on exploring the concept of Digital Enchantment and how it could be utilised to progress towards developing the Uncanny Object that appears to possess biological characteristics and apparent agency, yet is a fully artificial construct. The potential for the practical application of a design methodology guided by playful engagement with novel materials, microelectronics and digital fabrication technologies is analysed, taking into account Ingold’s concept of the textility of making (Ingold, 2011). Through exploring the notion of the Polymorphic Practitioner in the context of Alchemical Practice, a model for experiential knowledge generation through engaging in cross-disciplinary collaboration is developed. This is supported by a qualitative survey of European materials libraries, including accounts of site visits that evaluate the usefulness of materials libraries for creative practitioners invested in novel materiality as well as visually documenting a selection of the visited libraries’ most intriguing material holdings. Utilising a scientific testing protocol, a practical body of work that centres on conducting extensive experiments with smart materials is developed, with a particular focus on testing the compatibility and colour outcomes of chromic pigments in silicone. The resulting chromic silicone samples are collated, together with sourced smart materials, in a customised materials library. Investigational prototypes and the Microjewels collection of digital jewellery and wearable futures that responds to external and bodily stimuli whilst engaging the wearer through playful interaction are presented as another outcome of this body of research.
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Bhargava, Aarushi. "Dynamics of smart materials in high intensity focused ultrasound field." Diss., Virginia Tech, 2020. http://hdl.handle.net/10919/97994.
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Smart materials are intelligent materials that change their structural, chemical, mechanical, or thermal properties in response to an external stimulus such as heat, light, and magnetic and electric fields. With the increase in usage of smart materials in many sensitive applications, the need for a remote, wireless, efficient, and biologically safe stimulus has become crucial. This dissertation addresses this requirement by using high intensity focused ultrasound (HIFU) as the external trigger. HIFU has a unique capability of maintaining both spatial and temporal control and propagating over long distances with reduced losses, to achieve the desired response of the smart material. Two categories of smart materials are investigated in this research; shape memory polymers (SMPs) and piezoelectric materials.
SMPs have the ability to store a temporary shape and returning to their permanent or original shape when subjected to an external trigger. On the other hand, piezoelectric materials have the ability to convert mechanical energy to electrical energy and vice versa. Due to these extraordinary properties, these materials are being used in several industries including biomedical, robotic, noise-control, and aerospace.
This work introduces two novel concepts: First, HIFU actuation of SMP-based drug delivery capsules as an alternative way of achieving controlled drug delivery. This concept exploits the pre-determined shape changing capabilities of SMPs under localized HIFU exposure to achieve the desired drug delivery rate. Second, solving the existing challenge of low efficiency by focusing the acoustic energy on piezoelectric receivers to transfer power wirelessly.
The fundamental physics underlying these two concepts is explored by developing comprehensive mathematical models that provide an in-depth analysis of individual parameters affecting the HIFU-smart material systems, for the first time in literature. Many physical factors such as acoustic, material and dynamical nonlinearities, acoustic standing waves, and mechanical behavior of materials are explored to increase the developed models' accuracy. These mathematical frameworks are designed with the aim of serving as a basic groundwork for building more complex smart material-based systems under HIFU exposure.Doctor of Philosophy
Smart materials are a type of intelligent materials that have the ability to respond to external stimuli such as heat, light, and magnetic fields. When these materials respond, they can change their structural, thermodynamical, mechanical or chemical nature. Due to this extraordinary property, smart materials are being used in many applications including biomedical, robotic, space, microelectronics, and automobile industry. However, due to increased sensitivity and need for safety in many applications, a biologically safe, wireless, and efficient trigger is required to actuate these materials. In this dissertation, sound is used as an external trigger to actuate two types of smart materials: shape memory polymers (SMPs) and piezoelectric materials. SMPs have an ability to store a temporary (arbitrarily deformed) shape and return to their permanent shape when exposed to a trigger. In this dissertation, focused sound induced thermal energy acts as a trigger for these polymers. A novel concept of focused ultrasound actuation of SMP-based drug delivery capsules is proposed as a means to solve some of the challenges being faced in the field of controlled drug delivery. Piezoelectric materials have an ability to generate electric power when an external mechanical force is applied and vice versa. In this study, sound pressure waves supply the external force required to produce electric current in piezoelectric disks, as a method for achieving power transfer wirelessly. This study aims to solve the current problem of low efficiency in acoustic power transfer systems by focusing sound waves. This dissertation addresses the fundamental physics of high intensity focused ultrasound actuation of smart materials by developing comprehensive mathematical models and systematic experimental investigations, that have not been performed till now. The developed models enable an in-depth analysis of individual parameters including nonlinear material behavior, acoustic nonlinearity and resonance phenomena that affect the functioning of these smart systems. These mathematical frameworks also serve as groundwork for developing more complex systems.
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Stauffer, Erica F. "Reinterpreting Skins and Systems: Integrating Smart Materials with Traditional Construction." University of Cincinnati / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1337715982.
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Kang, Huaizhi. "Molecular engineering of nucleic acid towards functional and smart materials /." [Gainesville, Fla.] : University of Florida, 2009. http://purl.fcla.edu/fcla/etd/UFE0041192.
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