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Ibrahim, M. E. "Advanced applications of smart materials research for the enhancement of Australian defence capability." Fishermans Bend, Victoria : Defence Science and Technology Organisation, 2009. http://nla.gov.au/nla.arc-24764.
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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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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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Kang, Inpil. "Carbon Nanotube Smart Materials." University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1109710134.
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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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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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Wilson, Michael Thomas. "Technology advancement in intelligent buildings a through preplanning process pertaining to long-term maintainability /." Thesis, Available online, Georgia Institute of Technology, 2004:, 2004. http://etd.gatech.edu/theses/available/etd-08172004-150143/unrestricted/wilson%5Fmichael%5Ft%5F200412%5Fms.pdf.
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Thesis (M.S.)--Building Construction, Georgia Institute of Technology, 2005.Dr. Felix T. Uhlik III, Committee Member ; Mr. Cliff Stern, Committee Member ; Dr. Rita Oberle, Committee Member ; Ms. Kathy O. Roper, Committee Chair. Includes bibliographical references.
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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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Dai, Xiaochuan. "Multifunctional Three-Dimensional Nanoelectronic Networks for Smart Materials and Cyborg Tissues." Thesis, Harvard University, 2015. http://nrs.harvard.edu/urn-3:HUL.InstRepos:23845480.
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Nanomaterials provide unique opportunities at the interface between nanoelectronics and biology. “Bottom-up” synthesized nanowire(NW) with defined functionality can be assembled and enabled into three-dimensional(3D) flexible nanoelectronic networks. The micro- to nanoscale electronic units blur the distinction between electronics and cells/tissue in terms of length scale and mechanical stiffness. These unconventional 3D nanoelectronic networks can thus provide a path towards truly seamless integration of non-living electronics and living systems. In this thesis, I will introduce a general method for fabricating 3D macroporous NW nanoelectronic networks and their integration with hydrogel, elastomer and living tissues, with an emphasis on the realization of two-way communication between active nanoelectronics and the passive or living systems in which they are embedded.
First, fabrication of 3D macroporous NW nanoelectronic networks will be described. Examples showing hundreds of individually addressable, multifunctional nanodevices fully distributed and interconnected throughout 3D networks will be illustrated. Proof-of-concept studies of macroporous nanoelectronic networks embedded through hydrogels and polymers demonstrate the ability for dynamically mapping pH gradients and strain fields.
Second, a universal method to improve the long-term stability of semiconductor NWs in physiological environments using atomic layer deposition(ALD) of dielectric metal oxides shells on NW cores will be introduced. Long-term stability improvement by ALD of Al2O3 shells with different shell thickness and annealing conditions will be described and discussed. In addition, studies of semiconductor NW nanodevices with multilayer Al2O3/HfO2 shells indicates stability for up to two years in physiological solutions at 37◦C.
Third, 3D macroporous nanoelectronic networks were integrated with synthetic cardiac tissues to build “cyborg” cardiac tissues. Spatiotemporal mapping of action potential(AP) propagating throughout 3D cardiac tissue was carried out with sub-millisecond time resolution, allowing investigation of cardiac tissue development and responses to pharmacological agents. These results have promised the applications of cyborg tissues in the fields ranging from fundamental electrophysiology and regenerative medicine to pharmacological studies.
Finally, multifunctionallities of nanoelectronic devices for applications at the bio/nano interface will be discussed. Incorporation of NW field-effect-transistor(FET) and electrical stimulators in macroporous nanoelectronic networks demonstrates simultaneous recording and regulation of AP propagation in cyborg cardiac tissues. In addition, a convexed-NW FET bioprobe has been developed for simultaneous detection of AP and contraction force from individual cardiomyocyte. These explorations on the nanoelectronics functionalities highlight the capability to enable new communication modes between electronics and living tissues.Chemistry and Chemical Biology
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Kwak, Seung-Keon. "New modeling and control design techniques for aircraft structural dynamics using smart materials /." The Ohio State University, 1999. http://rave.ohiolink.edu/etdc/view?acc_num=osu1488188894442033.
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Dong, Biqin. "Cement-based piezoelectric ceramic composites for sensor applications in civil engineering /." View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202005%20DONG.
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MISKIN, ATUL. "BULK SYNTHESIS OF CARBON NANOTUBES BY CHEMICAL VAPOR DEPOSITION FOR SMART MATERIALS APPLICATIONS." University of Cincinnati / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1093033712.
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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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McCormick, Jason P. "Cyclic Behavior of Shape Memory Alloys: Materials Characterization and Optimization." Diss., Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-04052006-110226/.
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Thesis (Ph. D.)--Civil and Environmental Engineering, Georgia Institute of Technology, 2006.Gall, Kenneth, Committee Member ; Leon, Roberto, Committee Member ; Kurtis, Kimberly, Committee Member ; Jacobs, Laurence, Committee Member ; DesRoches, Reginald, Committee Chair.
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Schanandore, Thomas Charles. "Structural Enhancement Utilizing Smart Materials: Experiments and Applications Involving Piezoelectric Actuators and Shape Memory Alloys." Thesis, North Dakota State University, 2015. https://hdl.handle.net/10365/27693.
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Smart materials, within the realm of structural engineering, are mainly used as either sensoric mechanisms or as structural damping mechanisms. For the most part, structural enhancement utilizing smart materials is not seen in main stream structural engineering practices. Piezoelectric ceramics and shape memory alloys are two smart materials that are explored. In comparison shape memory alloys have far greater actuation strain (2% - 7%) than piezoelectric (0.08% - 0.11%) ceramics. Piezoelectric actuators are employed as surface actuators. Shape memory alloys are also explored in this manner, but the analysis is taken a step further where shape memory alloys are explored as beam and column retrofit elements. Because of the low mechanical range of the piezoelectric material, the potential for stress reduction is bound to lower stress applications. The general conclusion for shape memory alloys is that it would be suitable for high stress applications which include main stream steel applications.North Dakota EPSCoR
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Günther, Swen. "Innovative Smart Materials: Design meets Technology: Industry Research Project Week 2018." HTW Dresden, 2019. https://ul.qucosa.de/id/qucosa%3A35864.
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Kong, Xinguo. "APPLICATION OF NANOPOROUS MATERIALS IN MECHANICAL SYSTEMS." University of Akron / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=akron1150255954.
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Vijayaraghavan, Prasant. "Investigating the Effect of Thermoelectric Processing on Smart Ionomer Composites." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1534689821549276.
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Zade, Vishal B. "Rolling Resistance of Electrorheological Composites." University of Akron / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1435856708.
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Gil, Castell Óscar. "Development, characterisation and validation of functionalised polymer-based materials for smart applications." Doctoral thesis, Universitat Politècnica de València, 2019. http://hdl.handle.net/10251/107950.
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El estudio de nuevos materiales y metodologías ha resultado en un progreso exponencial de la ciencia de polímeros. Los recientes avances en la modificación de estos materiales, junto con el uso de técnicas de procesado novedosas, han aportado extraordinarias funcionalidades para afrontar las necesidades requeridas en aplicaciones específicas. En ese sentido, el objetivo de la presente tesis fue desarrollar la estrategia de investigación adecuada para la funcionalización de polímeros, basada en un esquema de múltiples etapas, implicando el diseño, procesado, caracterización y validación del cumplimiento de los requisitos de durabilidad específica y vida útil. Esta metodología se aplicó para aportar soluciones alternativas para aplicaciones como la foto-estabilización de poliolefinas al aire libre, el desarrollo de membranas de polielectrolitos para pilas de combustible y de andamios para ingeniería de tejidos.
La funcionalización de los polímeros se realizó mediante técnicas de modificación macromolecular, mezclado, y combinación con micro y nanopartículas. Se consideraron técnicas de procesado como la disolución-vertido, la extrusión por fusión en caliente, el moldeo por compresión y el electrohilado, las cuales permitieron obtener características fisicoquímicas específicas, que se evaluaron mediante técnicas de espectroscopia, cromatografía, microscopía y análisis térmico. Además, se realizaron los procedimientos de validación en condiciones de servicio reales o simuladas, que permitieron evaluar la idoneidad de los materiales desarrollados.
En el campo de la foto-estabilización de poliolefinas, la adición de micropartículas de silicio polidisperso proporcionó una elevada estabilidad al polipropileno (PP) sin aditivar frente a la irradiación solar, en términos de apariencia, estabilidad térmica y propiedades mecánicas.
En el diseño de polielectrolitos para pilas de combustible, se consideró el entrecruzado y sulfonación de poli(alcohol vinílico) (PVA) con ácido sulfosuccínico (SSA). También se estudió la combinación con óxido de grafeno (GO) y quitosano (CS). Tanto los nuevos films funcionalizados como los polielectrolitos nanofibrosos, mostraron estabilidad dimensional y térmica en condiciones de servicio, fueron aislantes eléctricos y revelaron un rendimiento prometedor en términos de conductividad protónica.
Se obtuvieron andamios funcionalizados para ingeniería de tejidos a partir de la mezcla de policaprolactona (PCL) y gelatina (Ge). El control del tiempo de disolución en un disolvente hidrolítico de ácido fórmico/acético antes del electrohilado permitió obtener andamios con características a medida, en términos de morfología, comportamiento físicoquímico y biocompatibilidad. Los andamios con proporciones equilibradas de PCL y Ge promovieron la adhesión y proliferación celular in vitro, así como una durabilidad adecuada en condiciones in vitro y durante la implantación in vivo.The understanding of new materials and methodologies have led to an exponential progress of polymer science. Recent advances in polymer modification and processing techniques have endorsed amazing functionalities to cover the features required in specific applications. The aim of this thesis was to develop appropriate research strategies of functionalisation of polymers based on a multi-stage scheme, involving the design, processing, characterisation, and validation to meet the requisites of specific durability and service life. This methodology was applied to provide alternative solutions that respond to service requirements in several applications, such as photo-stabilisation of polyolefins for outdoor applications, polyelectrolyte membranes for fuel cells, and scaffolds for tissue engineering. The functionalisation of polymers was performed by macromolecular modification, blending, and combination with micro and nanoparticles. Processing techniques such as solvent-casting, hot-melt extrusion, compression moulding and electrospinning permitted to obtain specific physico-chemical features, which were determined by spectroscopy, chromatography, microscopy and thermal analysis. In addition, a validation procedure was performed by means of real or simulated service conditions, which helped assess the suitability of the functionalised polymer-based materials. In the field of the photo-stabilisation of polyolefins, polydisperse silicon particles provided high stability to raw non-additivated polypropylene (PP) against sunlight irradiation in terms of appearance, thermal stability and mechanical properties. In order to design polyelectrolytes for fuel cells, the cross-linking and sulfonation of poly(vinyl alcohol) (PVA) with sulfosuccinic acid (SSA) was considered. The combination with graphene oxide (GO) and chitosan (CS) was also explored. The new functionalised films or nanofibrous polyelectrolytes, offered dimensional and thermal stability under service conditions, were electric insulators, and revealed promising performance in terms of proton conductivity. Functionalised blended scaffolds of polycaprolactone (PCL) and gelatin (Ge) were obtained for tissue engineering. The control of the dissolution time into a formic/acetic acid hydrolytic solvent prior to electrospinning permitted to obtain tailored scaffolds, in terms of nanofibrous morphology, physico-chemical performance and biocompatibility. The scaffolds with balanced ratios of PCL/Ge promoted in vitro cell adhesion and proliferation, as well as suited appropriate durability under in vitro conditions and during the in vivo implantation.
L'estudi de nous materials i metodologies ha resultat en un progrés exponencial de la ciència de polímers. Els recents avanços en la modificació d'aquests materials, juntament amb l'ús de noves tècniques de processat, han aportat extraordinàries funcionalitats per afrontar les necessitats requerides en aplicacions específiques. En aquest sentit, l'objectiu de la present tesi fou desenvolupar l'estratègia d'investigació adequada per a la funcionalització de polímers, basada en un esquema de múltiples etapes, implicant el disseny, processat, caracterització i validació del compliment dels requisits de durabilitat específica i vida útil. Aquesta metodologia es va aplicar per aportar solucions alternatives en aplicacions com la foto-estabilització de poliolefines exposades a l'aire lliure, el desenvolupament de membranes de polielectròlits per a piles de combustible i de bastides per a enginyeria de teixits. La funcionalització dels polímers es va realitzar mitjançant tècniques de modificació macromolecular, mescla, i combinació amb micro i nanopartícules. Es van considerar tècniques de processat com la dissolució-abocament, l'extrusió per fusió en calent, l'emmotllament per compressió i l'electrofilat, les quals van permetre obtenir característiques fisicoquímiques específiques, que es van avaluar mitjançant tècniques d'espectroscòpia, cromatografia, microscòpia i anàlisi tèrmic. A més, es van realitzar els procediments de validació en condicions de servei reals o simulades, que van permetre avaluar la idoneïtat dels materials desenvolupats. En el camp de la foto-estabilització de poliolefines, l'addició de micropartícules de silici polidispers va proporcionar una elevada estabilitat al polipropilè (PP) sense additivar davant de la irradiació solar, en termes d'aparença, estabilitat tèrmica i propietats mecàniques. En el disseny de polielectròlits per a piles de combustible, es va considerar el entrecreuament i sulfonació de poli(alcohol vinílic) (PVA) amb àcid sulfosuccínic (SSA). També es va estudiar la combinació amb òxid de grafè (GO) i quitosà (CS). Tant els nous films funcionalitzats com els polielectròlits nanofibrosos, mostraren estabilitat dimensional i tèrmica en condicions de servei, foren aïllants elèctrics i revelaren un rendiment prometedor en termes de conductivitat protònica. Es van obtenir bastides funcionalitzades per a enginyeria de teixits a partir de la mescla de policaprolactona (PCL) i gelatina (Ge). El control del temps de dissolució en un dissolvent hidrolític d'àcid fòrmic/acètic abans de l'electrofilat va permetre obtenir bastides amb característiques a mida, en termes de morfologia, comportament fisicoquímic i biocompatibilitat. Les bastides amb proporcions equilibrades de PCL i Ge van promoure l'adhesió i proliferació cel·lular in vitro, així com una durabilitat adequada en condicions in vitro i durant la implantació in vivo.
Gil Castell, Ó. (2018). Development, characterisation and validation of functionalised polymer-based materials for smart applications [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/107950
TESIS
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Deshmukh, Suraj Sharadchandra 1978. "Development, characterization and applications of magnetorheological fluid based "smart" materials on the macro-to-micro scale." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/38697.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, February 2007.Includes bibliographical references (p. 193-208).
Magnetorheological fluids belong to the class of field-responsive fluids that undergo large, reversible and fast changes in their rheological properties when acted upon by an external magnetic field. 'Smart' or controllable composite materials have been obtained by doping polymers, foams, fabrics etc. with these field-responsive fluids. The resulting composite materials have potential applications in numerous fields ranging from adaptive energy absorption, automotive crash protection to microfluidic valves, mixers and separation devices. A series of stable magnetorheological (MR) fluids have been systematically characterized under steady shearing, creep and large amplitude oscillatory shear (LAOS) flow conditions. A rheometer fixture for applying nearly uniform magnetic fields up to 0.4 T has been fabricated to measure both steady-state and transient changes in the fluid properties under applied fields. Stable MR fluids with a markedly improved dynamic response (yield stress as a function of magnetic field) compared to commercial fluids have been formulated by increasing the constituent particle size and by stabilizing the system against sedimentation. A new "soft-glassy rheology" model has been used to model the fluid response time and visco-elasto-plastic response under creep conditions and oscillatory loadings.
(cont.) The experiments and model show that the evolution of chain structure and plastic collapse in these suspensions exhibits a universal scaling with the dimensionless stress s = [sigma]/[sigma]y. Structure evolution, pattern formation and dynamics of MR fluid flow in microchannel geometries has been analyzed using high-speed digital video microscopy. In order to elucidate the mechanisms that control MR structure formation, experiments have been performed while varying the magnetic field, particle size, channel geometry, concentration and fluid composition. Excellent qualitative agreement has been obtained with Brownian Dynamics simulations and useful scalings based on interplay of magnetostatic & viscous forces have been extracted to understand the field-dependent fluid response on the macro & micro scale. Novel MR elastomeric materials and microparticles have been synthesized by doping photo-curable or thermo-curable polymers with field-responsive fluids. A high-throughput micromolding technique for synthesis of controllable particles of anisotropic shapes and sizes has been developed. Flexible and permanent chain-like structures have also been synthesized using amidation chemistry. Potential microfluidic applications such as field-responsive valves, mixers and separation devices using these 'smart' materials have also been investigated.
by Suraj Sharadchandra Deshmukh.
Ph.D.
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Cersoli, Trenton M. "Shape Memory Polymers Produced via Additive Manufacturing." Youngstown State University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1619817489890187.
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Headings, Leon Mark. "Modeling, characterization, and design of smart material driven stick-slip actuation mechanisms." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1141700440.
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Nick, Zachary H. "Foundations for Smart Metamaterials by Liquid Metal Digital Logic and Magnetoelastic Properties Control." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1587669303938667.
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Lowe, Robert Lindsey. "Finite-Deformation Modeling of Elastodynamics and Smart Materials with Nonlinear Electro-Magneto-Elastic Coupling." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1433276487.
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Konh, Bardia. "Smart Surgical Needle Actuated by Shape Memory Alloys for Percutaneous Procedures." Diss., Temple University Libraries, 2016. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/375030.
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Mechanical EngineeringPh.D.
Background: Majority of cancer interventions today are performed percutaneously using needle-based procedures, i.e. through the skin and soft tissue. Needle insertion is known as one of the recent needle-based techniques that is used in several diagnostic and therapeutic medical procedures such as brachytherapy, thermal ablations and breast biopsy. The difficulty in most of these procedures is to attain a precise navigation through tissue reaching target locations. Insufficient accuracy using conventional surgical needles motivated researchers to provide actuation forces to the needle’s body for compensating the possible errors of surgeons/physicians. Therefore, active needles were proposed recently where actuation forces provided by shape memory alloys (SMAs) are utilized to assist the maneuverability and accuracy of surgical needles. This work also aims to introduce a novel needle insertion simulation to predict the deflection of a bevel tip needle inside the tissue. Development of a model to predict the behavior of the needle steering in the soft tissue has been always a point of interest as it could improve the performance of many percutaneous needle-based procedures. Methods: In this work first, the actuation capability of a single SMA wire was studied. The complex response of SMAs was investigated via a MATLAB implementation of the Brinson model and verified via experimental tests. The material characteristics of SMAs were simulated by defining multilinear elastic isothermal stress-strain curves. Rigorous experiments with SMA wires were performed to determine the material properties as well as to show the capability of the code to predict a stabilized SMA transformation behavior with sufficient accuracy. The isothermal stress-strain curves of SMAs were simulated and defined as a material model for the Finite Element Analysis of the active needle. In the second part of this work, a three-dimensional finite element (FE) model of the active steerable needle was developed to demonstrate the feasibility of using SMA wires as actuators to bend the surgical needle. In the FE model, birth and death method of defining boundary conditions, available in ANSYS, was used to achieve the pre-strain condition on SMA wire prior to actuation. This numerical model was validated with needle deflection experiments with developed prototypes of the active needle. The third part of this work describes the design optimization of the active using genetic algorithm aiming for its maximum flexibility. Design parameters influencing the steerability include the needle’s diameter, wire diameter, pre-strain, and its offset from the needle. A simplified model was developed to decrease the computation time in iterative analyses of the optimization algorithm. In the fourth part of this work a design of an active needling system was proposed where actuation forces of SMAs as well as shape memory polymers (SMPs) were incorporated. SMP elements provide two major additional advantages to the design: (i) recovery of the SMP’s plastic deformation by heating the element above its glass transition temperature, and (ii) achieving a higher needle deflection by having a softer stage of SMP at higher temperatures with less amount of actuation force. Finally, in the fifth and last part of this study, an Arbitrary-Lagrangian-Eulerian formulation in LS-DYNA software was used to model the solid-fluid interactions between the needle and tissue. A 150mm long needle was considered to bend within the tissue due to the interacting forces on its asymmetric bevel tip. Some additional assumptions were made to maintain a reasonable computational time, with no need of parallel processing, while having practical accuracies. Three experimental tests of needle steering in a soft phantom were performed to validate the simulation. Results: The finite element model of the active needle was first validated experimentally with developed prototypes. Several design parameters affecting the needle’s deflection such as the needle’s Young’s modulus, the SMA’s pre-strain and its offset from the neutral axis of the cannula were studied using the FE model. Then by the integration of the SMA characteristics with the automated optimization schemes an improved design of the active needle was obtained. Real-time experiments with different prototypes showed that the quickest response and the maximum deflection were achieved by the needle with two sections of actuation compared to a single section of actuation. Also the feasibility of providing actuation forces using both SMAs and SMPs for the surgical needle was demonstrated in this study. The needle insertion simulation was validated while observing less than 10% deviation between the estimated amount of needle deflection by the simulation and by the experiments. Using this model the effect of needle diameter and its bevel tip angle on the final shape of the needle was investigated. Conclusion: The numerical and experimental studies of this work showed that a highly maneuverable active needle can be made using the actuation of multiple SMA wires in series. To maneuver around the anatomical obstacles of the human body and reach the target location, thin sharp needles are recommended as they would create a smaller radius of curvature. The insertion model presented in this work is intended to be used as a base structure for path planning and training purposes for future studies.
Temple University--Theses
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Nguyen, Tuan Minh. "MODELING OF THERMO-MECHANICAL BEHAVIOR OF NITINOL ACTUATOR FOR SMART NEEDLE APPLICATION." Master's thesis, Temple University Libraries, 2012. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/192929.
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Mechanical EngineeringM.S.M.E.
A large and increasing number of cancer interventions, including both diagnosis and therapy, involve precise placement of needles, which is extremely difficult. This challenge is due to lack of proper actuation of the needle (i.e., actuated from the proximal end, which is far away from the needle tip). To overcome this challenge, we propose to bend the needle using a smart actuator that applies bending forces on the needle body; thereby, improving the navigation of the needle. The smart actuator is designed with shape memory alloy (SMA) wires, namely Nitinol, due to their unique properties such as super-elasticity, shape memory effect, and biocompatibility. For accurate steering of the smart needle, there is a need to understand Nitinol thermo-mechanical behaviors. Various existing SMA constitutive models were investigated and compared. Since SMA is used as an actuator in this project, only one dimensional constitutive models are considered. Two distinct models with different phase transformation kinetic approaches were chosen. The first model was proposed by Terriault and Brailovski (J. Intell. Mat. Systems Structures, 2011) using a modified one dimensional Likhachev formulation. The second model was developed by Brinson (J. Intell. Mat. Systems Structures , 1993). Since all SMA constitutive models are empirically based, several important materials' constants such as Phase Transformation Temperatures are needed. The four Transformation Temperatures are: Martensite start (Ms), Martensite finish (Mf), Austenite start (As), Austenite finish (Af). Differential Scanning Calorimetry (DSC) was used to obtain these constants. These temperatures are also influenced by stress, defined by the Clausius-Clayperon coefficients. The coefficients were obtained by measuring Nitinol temperature and displacement response under various constant stress conditions. In order to study its actuation behavior, Nitinol wires under constant strain configuration and resistance heating were tested for their force response. The thermo-mechanical responses were then compared with numerical simulations. While Terriault and Brailovski resistance heating formulation agrees strongly with temperature responses, the model cannot be used to simulate the actuator mechanical responses. Brinson model simulations of the force responses were found to agree well with experimental results. In conclusion, Terriault and Brailovski resistance heating formulation should be coupled with Brinson model to accurately simulate Nitinol actuation behavior for the smart needle.
Temple University--Theses
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Kutikov, Artem B. "Amphiphilic Degradable Polymer/Hydroxyapatite Composites as Smart Bone Tissue Engineering Scaffolds: A Dissertation." eScholarship@UMMS, 2011. http://escholarship.umassmed.edu/gsbs_diss/755.
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Over 600,000 bone-grafting operations are performed each year in the United States. The majority of the bone used for these surgeries comes from autografts that are limited in quantity or allografts with high failure rates. Current synthetic bone grafting materials have poor mechanical properties, handling characteristics, and bioactivity. The goal of this dissertation was to develop a clinically translatable bone tissue engineering scaffold with improved handling characteristics, bioactivity, and smart delivery modalities. We hypothesized that this could be achieved through the rational selection of Food and Drug Administration (FDA) approved materials that blend favorably with hydroxyapatite (HA), the principle mineral component in bone. This dissertation describes the development of smart bone tissue engineering scaffolds composed of the biodegradable amphiphilic polymer poly(D,L-lactic acid-co-ethylene glycol-co- D,L-lactic acid) (PELA) and HA. Electrospun nanofibrous HA-PELA scaffolds exhibited improved handling characteristics and bioactivity over conventional HApoly( D,L-lactic acid) composites. Electrospun HA-PELA was hydrophilic, elastic, stiffened upon hydration, and supported the attachment and osteogenic differentiation of rat bone marrow stromal cells (MSCs). These in vitro properties translated into robust bone formation in vivo using a critical-size femoral defect model in rats. Spiral-wrapped HA-PELA scaffolds, loaded with MSCs or a lowdose of recombinant human bone morphogenetic protein-2, templated bone formation along the defect. As an alternate approach, PELA and HA-PELA were viii rapid prototyped into three-dimensional (3-D) macroporous scaffolds using a consumer-grade 3-D printer. These 3-D scaffolds have differential cell adhesion characteristics, swell and stiffen upon hydration, and exhibit hydration-induced self-fixation in a simulated confined defect. HA-PELA also exhibits thermal shape memory behavior, enabling the minimally invasive delivery and rapid (>3 sec) shape recovery of 3-D scaffolds at physiologically safe temperatures (~ 50ºC). Overall, this dissertation demonstrates how the rational selection of FDA approved materials with synergistic interactions results in smart biomaterials with high potential for clinical translation.
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Kutikov, Artem B. "Amphiphilic Degradable Polymer/Hydroxyapatite Composites as Smart Bone Tissue Engineering Scaffolds: A Dissertation." eScholarship@UMMS, 2014. https://escholarship.umassmed.edu/gsbs_diss/755.
Full textAbstract:
Over 600,000 bone-grafting operations are performed each year in the United States. The majority of the bone used for these surgeries comes from autografts that are limited in quantity or allografts with high failure rates. Current synthetic bone grafting materials have poor mechanical properties, handling characteristics, and bioactivity. The goal of this dissertation was to develop a clinically translatable bone tissue engineering scaffold with improved handling characteristics, bioactivity, and smart delivery modalities. We hypothesized that this could be achieved through the rational selection of Food and Drug Administration (FDA) approved materials that blend favorably with hydroxyapatite (HA), the principle mineral component in bone. This dissertation describes the development of smart bone tissue engineering scaffolds composed of the biodegradable amphiphilic polymer poly(D,L-lactic acid-co-ethylene glycol-co- D,L-lactic acid) (PELA) and HA. Electrospun nanofibrous HA-PELA scaffolds exhibited improved handling characteristics and bioactivity over conventional HApoly( D,L-lactic acid) composites. Electrospun HA-PELA was hydrophilic, elastic, stiffened upon hydration, and supported the attachment and osteogenic differentiation of rat bone marrow stromal cells (MSCs). These in vitro properties translated into robust bone formation in vivo using a critical-size femoral defect model in rats. Spiral-wrapped HA-PELA scaffolds, loaded with MSCs or a lowdose of recombinant human bone morphogenetic protein-2, templated bone formation along the defect. As an alternate approach, PELA and HA-PELA were viii rapid prototyped into three-dimensional (3-D) macroporous scaffolds using a consumer-grade 3-D printer. These 3-D scaffolds have differential cell adhesion characteristics, swell and stiffen upon hydration, and exhibit hydration-induced self-fixation in a simulated confined defect. HA-PELA also exhibits thermal shape memory behavior, enabling the minimally invasive delivery and rapid (>3 sec) shape recovery of 3-D scaffolds at physiologically safe temperatures (~ 50ºC). Overall, this dissertation demonstrates how the rational selection of FDA approved materials with synergistic interactions results in smart biomaterials with high potential for clinical translation.
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Xu, Mubing. "Adaptive-passive and active control of vibration and wave propagation in cylindrical shells using smart materials." Akron, OH : University of Akron, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=akron1123211712.
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Dissertation (Ph.D.)--University of Akron, Dept. of Mechanical Engineering, 2005."August, 2005." Title from electronic dissertation title page (viewed 12/27/2005) Advisor, Pizhong Qiao; Co-Advisor, Gangbing Song; Committee members, Wieslaw K. Binienda, Kevin L. Kreider, Paul C. K. Lam, Dane Quinn; Department Chair, Celal Batur, Wieslaw K. Binienda; Dean of the College, George K. Haritos; Dean of the Graduate School, George R. Newkome Includes bibliographical references.
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Jiang, Zhuoying. "Smart Photocatalytic Building Materials for Autogenous Improvement of Indoor Environment: Experimental, Physics-Based, and Data-Driven Modeling Approaches." Case Western Reserve University School of Graduate Studies / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=case1626277456472492.
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Liu, Jia. "Biomimetics through nanoelectronics: development of three-dimensional macroporous nanoelectronics for building smart materials, cyborg tissues and injectable biomedical electronics." Thesis, Harvard University, 2014. http://dissertations.umi.com/gsas.harvard:11510.
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Nanoscale materials enable unique opportunities at the interface between physical and life sciences. The interface between nanoelectronic devices and biological systems makes possible communication between these two diverse systems at the length scale relevant to biological functions. The development of a bottom-up paradigm allows the nanoelectronic units to be synthesized and patterned on unconventional substrates. In this thesis, I will focus on the development of three-dimensional (3D) nanoelectronics, which mimics the structure of porous biomaterials to explore new methods for seamless integration of electronics with other materials, with a special focus on biological tissue.Chemistry and Chemical Biology
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Toker, Guher P. "CHARACTERIZATION OF THE SHAPE MEMORY BEHAVIOR OF HIGH STRENGTH NiTiHfPd SHAPE MEMORY ALLOYS." UKnowledge, 2018. https://uknowledge.uky.edu/me_etds/114.
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NiTiHf alloys have emerged as potential materials for applications requiring high transformation temperatures (> 100 °C) with high strength and work output. Although they have high transformation temperatures, their low damping capacity, brittleness and poor superelastic responses (of Ti-rich NiTiHf) impedes their wider usage in many industrial applications. In this study, the quaternary alloying element of Pd has been added to NiTiHf alloys to improve and tailor their shape memory behavior,. NiTiHfPd alloys were systematically examined regarding the composition and heat treatments effects.
Effects of substituting Hf with Ti on the shape memory behavior of NiTHfPd alloys were investigated. There compositions were selected as Ni40.3Ti34Hf20Pd5 Ni40.3Ti39.7Hf15Pd5 and Ni40.3Ti44.7Hf10Pd5 (at.%). Their transformation temperatures, microstructure and shape memory properties were revealed and compared with conventional shape memory alloys. It was revealed that their transformation temperatures increases but transformation strain decreases with the increment of Hf content.
Additionally, superelastic responses of Ni45.3Ti29.7Hf20Pd5 andNi45.3Ti39.7Hf10Pd5 alloys were investigated. Transformation temperatures of polycrystalline Ni45.3Ti29.7Hf20Pd5are highly dependent on aging temperatures and they can be altered widely from room temperature to 250 oC.
Finally, the damping capacity of the Ni45.3Ti39.7Hf10Pd5 polycrystal and [111]-oriented Ni45.3Ti29.7Hf20Pd5 single crystal were investigated. The damping capacities were found to be 16-25 J.cm-3, and 10-23 J.cm-3 for the Ni45.3Ti39.7Hf10Pd5 and [111]-oriented Ni45.3Ti29.7Hf20Pd5 alloys, respectively.
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Sutula, Danas. "Energy minimising multi-crack growth in linear-elastic materials using the extended finite element method with application to Smart-Cut™ silicon wafer splitting." Thesis, Cardiff University, 2016. http://orca.cf.ac.uk/95561/.
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We investigate multiple crack evolution under quasi-static conditions in an isotropic linear-elastic solid based on the principle of minimum total energy, i.e. the sum of the potential and fracture energies, which stems directly from the Griffith’s theory of cracks. The technique, which has been implemented within the extended finite element method, enables minimisation of the total energy of the mechanical system with respect to the crack extension directions. This is achieved by finding the orientations of the discrete crack-tip extensions that yield vanishing rotational energy release rates about their roots. In addition, the proposed energy minimisation technique can be used to resolve competing crack growth problems. Comparisons of the fracture paths obtained by the maximum tension (hoop-stress) criterion and the energy minimisation approach via a multitude of numerical case studies show that both criteria converge to virtually the same fracture solutions albeit from opposite directions. In other words, it is found that the converged fracture path lies in between those obtained by each criterion on coarser numerical discretisations. Upon further investigation of the energy minimisation approach within the discrete framework, a modified crack growth direction criterion is proposed that assumes the average direction of the directions obtained by the maximum hoop stress and the minimum energy criteria. The numerical results show significant improvements in accuracy (especially on coarse discretisations) and convergence rates of the fracture paths. The XFEM implementation is subsequently applied to model an industry relevant problem of silicon wafer cutting based on the physical process of Smart-CutTM technology where wafer splitting is the result of the coalescence of multiple pressure-driven micro-crack growth within a narrow layer of the prevailing micro-crack distribution. A parametric study is carried out to assess the influence of some of the Smart-CutTM process parameters on the post-split fracture surface roughness. The parameters that have been investigated, include: mean depth of micro-crack distribution, distribution of micro-cracks about the mean depth, damage (isotropic) in the region of micro-crack distribution, and the influence of the depth of the buried-oxide layer (a layer of reduced stiffness) beneath the micro-crack distribution. Numerical results agree acceptably well with experimental observations.
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Bücker, Dennis. "Designing Applications for Smart Cities: A designerly approach to data analytics." Thesis, Malmö högskola, Fakulteten för kultur och samhälle (KS), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-23305.
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The purpose of this thesis is to investigate the effects of a designerly approach to data analytics. The research was conducted during the Interaction Design Master program at Malmö University in 2017 and follows a research through design approach where the material driven design process in itself becomes a way to acquire new knowledge. The thesis uses big data as design material for designers to ideate connected products and services in the context of smart city applications. More specifically, it conducts a series of material studies that show the potential of this new perspective to data analytics. As a result of this research a set of designs and exercises are presented and structured into a guide. Furthermore, the results emphasize the need for this type of research and highlights data as a departure material as of special interest for HCI.
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Simpson, Brian Keith Jr. "Strain engineering as a method for manufacturing micro- and; nano- scale responsive particles." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34728.
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Strain engineering is used as a means of manufacturing micro- and nano- scale particles with the ability to reversibly alter their geometry from three dimensional tubes to two dimensional flat layers. These particles are formed from a bi-layer of two dissimilar materials, one of which is the elastomeric material polydimethylsiloxane (PDMS), deposited under stress on a sacrificial substrate. Upon the release of the bi-layer structure from the substrate, interfacial residual stress is released resulting in the formation of tubes or coils. These particles possess the ability to dramatically alter their geometry and, consequently, change some properties that are reversible and can be triggered by a stimulus. This work focuses on the material selection and manufacturing of the bi-layer structures used to create the responsive particles and methods for characterizing and controlling the responsive nature of the particles. Furthermore, the potential of using these particles for a capture/release application is explored, and a systematic approach to scale up the manufacturing process for such particles is provided. This includes addressing many of the problems associated with fabricating ultra-thin layers, tuning the size of the particles, understanding how the stress accumulated at the interface of a bi-layer structure can be used as a tool for triggering a response as well as developing methods (i.e. experiments and applications) that allow the demonstration of this response.
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Honarvar, Mohammad. "THERMOMECHANICAL CHARACTERIZATION OF ONE-WAY SHAPE MEMORY NITINOL AS AN ACTUATOR FOR ACTIVE SURGICAL NEEDLE." Diss., Temple University Libraries, 2014. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/301891.
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Mechanical EngineeringPh.D.
Needle-based intervention insertion is one of the common surgical techniques used in many diagnostic and therapeutic percutaneous procedures. The success of such procedures highly depends on the accuracy of needle placement at target locations. An active needle has the potential to enhance the accuracy of needle placement as well as to improve clinical outcome. Bending forces provided by the attached actuators can assist the maneuverability in order to reach the targets following a desired trajectory. There are three major research parts in the development of active needle project in the Composites Laboratory of Temple University. They are thermomechanical characterization of shape memory alloy (SMA) or Nitinol as an actuator for smart needle, mechanical modeling and design of smart needles, and study of tissue needle interaction. The characterization of SMA is the focus of this dissertation. Unique thermomechanical properties of Nitinol known as shape memory effect and superelasticity make it applicable for different fields such as biomedical, structural and aerospace engineering. These unique behaviors are due to the comparatively large amount of recoverable strain which is being produced in a martensitic phase transformation. However, under certain ranges of stresses and temperatures, Nitinol wires exhibit unrecovered strain (also known as residual strain); which limits their applicability. Therefore, for applications that rely on the strain response in repetitive loading and unloading cycles, it is important to understand the generation of the unrecovered strain in the Nitinol wires. In this study, the unrecovered strain of Nitinol wires with various diameters was investigated, using two experimental approaches: constant stress and uniaxial tensile tests. Moreover, a critical range of stress was found beyond which the unrecovered strain was negligible at temperatures of 70 to 80C depending on the wire diameter. Wire diameters varied from 0.10 to 0.29 mm were tested and different ranges of critical stress were found for different wire diameters. The transformation temperatures of different wire diameters at zero stress have been achieved by performing the Differential Scanning Calorimetry (DSC) test. The actuation force created by Nitinol wire is measured through constant strain experiment. X-Ray Diffraction (XRD) study was also performed to investigate the phase of Nitinol wires under various thermomechanical loading conditions. In summary, the effect of wire diameter on the required critical stresses to avoid the unrecovered strain between first and second cycle of heating and cooling are presented and the results of both mechanical tests are justified by the results obtained from the XRD study.
Temple University--Theses
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Mirzaabedini, Sohrab. "Angular Analysis of a Wide-Band Energy Harvester based on Mutually Perpendicular Vibrating Piezoelectric Beams." Thesis, University of North Texas, 2016. https://digital.library.unt.edu/ark:/67531/metadc955086/.
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The recent advancements in electronics and the advents of small scaled instruments has increased the attachment of life and functionality of devices to electrical power sources but at the same time granted the engineers and companies the ability to use smaller sources of power and batteries. Therefore, many scientists have tried to come up with new solutions for a power alternatives. Piezoelectric is a promising material which can readily produce continuous electric power from mechanical inputs. However, their power output is dependent upon several factors such as, system natural frequency, their position in the system, the direction of vibration and many other internal and external factors. In this research the working bandwidth of the system is increased through utilizing of two different piezoelectric beam in different directions. The dependency of output power with respect to rotation angle and also the frequency shift due to the rotation angle is studied.
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Guo, Xiaolei. "Corrosion inhibition of aluminum alloy 2024-T3 based on smart coatings, hybrid corrosion inhibitors, and organic conversion coatings." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1461188604.
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Johnson, Timothy Michael. "Strain Monitoring of Carbon Fiber Composite with Embedded Nickel Nano-Composite Strain Gage." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2622.
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Carbon fiber reinforced plastic (CFRP) composites have extensive value in the aerospace, defense, sporting goods, and high performance automobile industries. These composites have huge benefits including high strength to weight ratios and the ability to tailor their properties. A significant issue with carbon fiber composites is the potential for catastrophic fatigue failure. To better understand this fatigue, there is first a huge push to measure strain accurately and in-situ to monitor carbon fiber composites. In this paper, piezoresistive nickel nanostrand (NiNs) nanocomposites were embedded in between layers of carbon fiber composite for real time, in situ strain monitoring. Several different embedding methods have been investigated. These include the direct embedding of a patch of dry NiNs and the embedding of NiNs-polymer matrix nanocomposite patches which are insulated from the surrounding carbon fiber. Also, two different polymer matrix materials were used in the nanocomposite to compare the piezoresistive signal. These nanocomposites are shown to display repeatable piezoresistivity, thus becoming a strain sensor capable of accurately measuring strain real time and in-situ. This patch has compatible mechanical properties to existing advanced composites and shows good resolution to small strain. This method of strain sensing in carbon fiber composites is more easily implemented and used than other strain measurement methods including fiber Bragg grating and acoustic emissions. To show that these embedded strain gages can be used in a variety of carbon fiber components, two different applications were also pursued.
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Backe, Carin. "Enhancing textile electrode performance : Regulating moisture management through textile structure." Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-12389.
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The medical field has been a part of the smart textile area for quite some time. With time come technological advancement and the two fields converge on more and more areas. One such area is that of using textile electrodes, textrodes, for measuring bioelectrical activity, such as heart rate for ECG analysis. There are many components that make for a successful textile electrode and though many studies have been made in the subject there are several aspects that still are difficult. By using textile electrodes the problem with skin irritation from electrolyte gels, commonly used for conventional electrodes, is avoided, however dry textrodes create disturbances in the output signal (heart rate) while subjected to movement and internal dimensional changes. The addition of moisture to a textrode has shown to decrease these intermittent disturbances but the knowledge about fundamental textile structural influence in the matter has not been fully investigated. This study investigates a flat, a 2-thread fleece and an open structure, and their relation to moisture both as textile structures and as textrodes. This way the possibilities of utilising moisture to increase performance in a textrode purpose can be examined and to what extent the textile structure plays a part in that exploitation. The material composition of textile structures also affects their properties The introduction of assistive materials, polyester and viscose, into the Shieldex (conductive yarn) structures is done to test core moisture management properties such as surface tension, absorption and moisture content, and correlate them to electrical properties necessary for textrode function. In the end the gap between textile structure and end product in form of a textrode is closed as the impedance and microclimate of the textrodes are studied. This is mainly to tie together the fundamental textile structures with a complex textile construction. In conclusion the complexity is also confirmed as structural, materialistic and external influences has an impact on the results. The influence of moisture on lowered resistance and impedance in the structures is confirmed but the impact of textile structure can also be seen. The 2-thread fleece and open structures often has a more positive impact on results and therefore has the possibility of enhancing performance of a textrode for bioelectrical signal monitoring. With these results a more effective way of producing long-lasting, patient-friendly, textrodes can be derived and in the future lead to better care in the medical areas.
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Anderson, Walter. "Development of an Intervertebral Cage Using Additive Manufacturingwith Embedded NiTi Hinges for a Minimally Invasive Deployment." University of Toledo / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1368182356.
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FAN, HUI. "A BOUNDARY ELEMENT METHOD FOR THE ANALYSIS OF THIN PIEZOELECTRIC SOLIDS." University of Cincinnati / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin988811258.
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Sinko, Robert Arnold. "Characterization, Modeling, and Applications of Novel Magneto-Rheological Elastomers." Miami University Honors Theses / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=muhonors1335236738.
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Carias, Vinicio. "Development of Polymer Composite Based Enabling Technologies for Lab-on-a-Chip Devices." Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/5654.
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This dissertation presents enabling technologies to fabricate thermo-responsive polymer composite based Lab-on-a-Chip (LOC) devices. LOC devices, also known as micro-total-analytical systems (microTAS) or microfluidic devices can amalgamate miniaturized laboratory functions on a single chip. This significant size reduction decreases the amount of required fluid volumes down to nano or pico-liters. The main commercial application of LOC devices is the biomedical fields. However, these devices are anticipated to make a technological revolution similar to the way miniaturization changed computers. In fact, medical and chemical analyses are predicted to shift from room-sized laboratories to hand-held portable devices.
This dissertation is divided into three technologies. First, a series of terpolymer systems were synthesized and characterized to fabricate crosslinked coatings for phototunable swelling and create chemically patterned regions in order to conjugate cationic markers, proteins, or nanoparticles to the terpolymer coating. Second, antifouling surfaces were fabricated using magnetic thermo-responsive hydrogel structures via soft lithography. The structures were remote control activated with the use of AC magnetic fields. Finally, in order for LOC devices to fulfill its promise of bringing a laboratory to a hand-held device, they will have to be integrated with CMOS technology. Packaging will play a crucial role in this process. The last section will focus on the importance of coefficient of thermal expansion (CTE) mismatch in multi-chip modules.
For the first technology, multi-functionalized terpolymer systems have been developed comprising of three units: N-isopropylacrylamide (NIPAAm), a stimuli responsive monomer that swells and collapses in response to temperature; methacryloxybenzophenone (MaBP), a photo-crosslinkable monomer that is activated at λ = 365 nm; and phenacyl methacrylate (PHEm), a photolabile protected functional group that generates localized free carboxyl groups in response to deprotection at λ = 254 nm. The multifunctional terpolymers can be spin-casted to form thin films of well-defined thickness, photo-crosslinked by a long UV wavelength light (λ = 365 nm) to form distinct structural patterns, and subsequently photo-chemically modified by a short UV wavelength light (λ = 254 nm). The photocleavage reaction by UV irradiation allows the production of free carboxylic groups that can be used to conjugate cationic markers, proteins, or nanoparticles to the terpolymer coating. Furthermore, the free carboxyl groups can be used to locally tune the swelling characteristics and transition temperature of the coatings.
For the second technology, when Fe3O4 magnetic nanoparticles are integrated into PNIPAAm based composite systems, their resultant hyperthermia behavior becomes an ideal mechanism for remote controlled actuation. In this work, nano Fe3O4 octopods were seeded in fabricated PNIPAAm hydrogel micro-actuators. When the magnetic hydrogel structures were exposed to a magnetic field strength of 63 kA/m at a frequency of 300 kHz, the hydrogel micro-beams underwent a buckling effect when the field was absent and an unbuckling effect when the field was present. The hydrogel micro-beams were fabricated at an approximate distance from one another developing micromanipulating surfaces that were remote control activated. The response time, heating efficiency, and magnetic behavior were thoroughly studied. Lastly, micron sized polystyrene beads were exposed to the antifouling surfaces and movement of the beads was observed as the magnetic hydrogel micro-beams underwent their physical changes.
For the third technology, a major reason of device failure in multi-chip module assemblies is a CTE mismatch between the underfill encapsulant material and the integrated circuit chip. Some of the failure mechanisms of microelectronic packaging due to CTE mismatch include fractures, delamination, or cracks through the device. In this section, the CTE of a commercially available underfill material is greatly reduced by loading the polymer resin material with hollow glass beads, to realize an overall effective CTE of 6.6 ppm/°C. Furthermore, the newly developed composite material exhibited outstanding thermomechanical stability at high temperatures beyond 150°C by holding a 3X lower CTE and a higher glass transition temperature.
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Lee, Yong Keat. "Active vibration control of a piezoelectric laminate plate using spatial control approach." Title page, abstract and table of contents only, 2005. http://hdl.handle.net/2440/37711.
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This thesis represents the work that has been done by the author during his Master of Engineering Science candidature in the area of vibration control of flexible structures at the School of Mechanical Engineering, The University of Adelaide, between March 2003 and June 2004. The aim of this research is to further extend the application of the Spatial Control Approach for two-dimensional flexible structures for attenuating global structural vibration with the possible implication of reduction in noise radiation. The research was concentrated on a simply supported thin flexible plate, using piezoelectric ceramic materials as actuators and sensors. In this work, active controllers were designed for the purpose of controlling only the first five vibration modes (0-500Hz) of the plate. A spatial controller was designed to minimize the total energy of the spatially distributed signal, which is reflected by the spatial H2 norm of the transfer function from the disturbance signal to the vibration output at every point over the plate. This approach ensures the vibration contributed by all the in bandwidth (0-500 Hz) vibration modes is minimized, and hence is capable of minimizing vibration throughout the entire plate. Within the control framework, two cases were considered here; the case when the prior knowledge of the incoming disturbance in terms of reference signal is vailable and the case when it is not available. For the case when the reference signal is available, spatial feedforward controller was designed; whereas for the case when the reference signal is not available, spatial feedback controller was designed to attenuate the global disturbance. The effectiveness of spatial controllers was then compared with that of the standard point-wise controllers numerically and experimentally. The experimental results were found to reflect the numerical results, and the results demonstrated that spatial controllers are able to reduce the energy transfer from the disturbance to the structural output across the plate in a more uniform way than the point-wise controllers. The research work has demonstrated that spatial controller managed to minimize the global plate vibrations and noise radiation that were due to the first five modes.Thesis (M.Eng.Sc.)--School of Mechanical Engineering, 2005.
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Sarawate, Neelesh Nandkumar. "Characterization and Modeling of the Ferromagnetic Shape Memory Alloy Ni-Mn-Ga for Sensing and Actuation." The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1220848509.
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Acosta, Pablo. "Influence des étapes technologiques du procédé Smart CutTM sur l'uniformité d'épaisseur des substrats de SOI : Approche multi-échelle." Phd thesis, Université Paul Sabatier - Toulouse III, 2014. http://tel.archives-ouvertes.fr/tel-01060076.
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Les substrats de silicium sur isolant totalement désertées (FD-SOI, pour Fully-Depleted Silicon-On-Insulator), se révèlent être une matière très prometteuse pour le développement des nouvelles technologies CMOS. Un substrat FD-SOI est formé d'une couche superficielle de silicium cristallin, extrêmement fine (~ 10 nm), disposée sur une couche d'oxyde enterrée (BOx) qui est elle-même portée par un substrat épais de silicium (~ 750 µm). En effet, il a été démontré que les caractéristiques des transistors fabriqués sur FD-SOI dépendent fortement de l'épaisseur de la fine couche de silicium. Il est donc indispensable que les variations d'épaisseur soient contrôlées avec une précision sous-nanométrique et ce sur une très large plage de fréquences spatiales (entre 10 nm et 300 mm) ce qui représente un grand défi pour l'industrie du semi-conducteur et en particulier pour la technologie CMOS. Au cours de cette thèse, des méthodes de caractérisation multi-échelle basées sur l'utilisation de la densité spectrale de puissance (PSD) et permettant le traitement des données obtenues par différentes techniques expérimentales, ont été développées. Cela permet de caractériser la rugosité et les variations d'épaisseur de couches fines sur l'intégralité de la bande spectrale d'intérêt. Ces outils ont permis l'étude de la corrélation entre la topographie de surface et les variations d'épaisseur du film de silicium. Ainsi, il a été mis en évidence qu'en fonction de la fréquence spatiale les variations d'épaisseur peuvent être supérieures, inférieures ou du même ordre de grandeur que celles de la topographie. En outre, les principales étapes technologiques entrant en jeu dans la technologie Smart CutTM pour la fabrication de substrats FD-SOI, ont été analysées, en particulier leur impact sur l'uniformité d'épaisseur de la couche de silicium. Cette analyse a révélé l'existence de trois régions spectrales montrant un comportement fractal avec des exposants de rugosité distincts, ceci permettant de déterminer les empreintes spectrales de certaines étapes technologiques du procédé, e.g., la propagation de la fracture [entre 1.10-5 et 2.10-3 µm-1], la diffusion de surface [entre 0.3 et 1 µm-1] et l'oxydation thermique [entre 1 et 10 µm-1]. De plus, la contribution spectrale résultant de la distribution de microfissures générées lors de l'implantation ionique, est établie [entre 0.03 et 1 µm-1]. Par la suite, l'influence des conditions de l'implantation ionique sur la topographie de surface après fracture ont été examinées. En effet, dans le cas de l'implantation H+, la rugosité augmente avec la dose ionique implantée. L'impact de l'ordre d'implantation, dans le cas de la co-implantation H+-He+ a également été traité. En outre, les phénomènes physiques à l'origine du lissage thermique par diffusion surfacique ont été investigués. Un modèle paramétrique décrivant l'évolution de la topographie de surface au cours d'un traitement thermique, a été développé à partir de l'équation de diffusion surfacique de Mullins-Herring. Deux termes stochastiques correspondant d'une part aux fluctuations thermiques et d'autre part au phénomène d'oxydation/évaporation, ont été ajoutés. Ce modèle permet donc de prédire l'évolution de la topographie des surfaces de silicium traitées par recuit thermique dans une atmosphère réductrice et pour des températures supérieures à celle de la transition rugueuse. Les données expérimentales décrivant l'évolution de la rugosité et la cinétique de diffusion sont en parfait accord avec les valeurs théoriques. L'optimisation des paramètres expérimentaux peut être réalisée suite à l'étude des limitations inhérentes au lissage des surfaces de silicium par recuit thermique rapide (RTA). Enfin, l'évolution de la topographie lors de l'oxydation thermique permet de mettre en évidence un comportement fractal présentant un exposant de rugosité (α=-0.5) montrant un bon accord avec le modèle de croissance de Edward-Wilkinson. Par ailleurs, l'influence de divers paramètres, entrant en jeu dans le polissage mécano-chimique (CMP), a été étudiée expérimentalement. Ce travail fournit l'ensemble des outils nécessaires à l'analyse multi-échelle de la topographie ainsi que des variations d'épaisseur des couches fines, sur une vaste gamme spectrale. L'étude approfondie des différentes étapes technologiques, permet une meilleure compréhension de ces dernières et facilite ainsi l'amélioration de l'uniformité de l'épaisseur pour des couches fines.
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KANDELL, BRIAN M. "PIEZOELECTRIC POLYMER (PVDF) RIBBON FOR CHOCHLEAR IMPLANTATION - GUIDELINES AND COMPARISONS WITH TOOTHBRUSH STYLE PROTOTYPES." University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1141311212.
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Wolcott, Paul Joseph. "Toward Load Bearing Reconfigurable Radio Frequency Antenna Devices Using Ultrasonic Additive Manufacturing." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1338385633.
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