Global ETD Search

1	Development of Conductive Polymer Membranes for Energy Applications Wang, Jingwen 17 August 2012 (has links) In this thesis, three types of conductive membranes were fabricated and characterized for potential energy applications such as fuel cells and solar photovoltaics. First, a single layer conductive polypyrrole (PPy) membrane was synthesized and activated. Through image analysis, surface pore geometry changes were analyzed. The single layer PPy membrane was proposed as a possible additional layer or coating in polymer electrolyte membrane fuel cells. Next, a novel adaptive trilayer PPy membrane was fabricated. The membranes were activated, and characterized through changes in surface wrinkle, roughness and contact angle. A dynamic range of surface properties were observed. Lastly, conductive fibrous membranes were fabricated with electrospinning. Two methods were utilized to spin conductive fibers including the incorporation of multi-walled carbon nanotubes (MWCNT) in polystyrene (PS) and the utilization of vapor phase polymerization (VPP) to chemically synthesize PPy on electrospun FeCl3/PS oxidant fibers. Properties including fiber morphology, thermal stability and conductivity were characterized. conductive polymers activation surface property 0548
2	Development of Conductive Polymer Membranes for Energy Applications Wang, Jingwen 17 August 2012 (has links) In this thesis, three types of conductive membranes were fabricated and characterized for potential energy applications such as fuel cells and solar photovoltaics. First, a single layer conductive polypyrrole (PPy) membrane was synthesized and activated. Through image analysis, surface pore geometry changes were analyzed. The single layer PPy membrane was proposed as a possible additional layer or coating in polymer electrolyte membrane fuel cells. Next, a novel adaptive trilayer PPy membrane was fabricated. The membranes were activated, and characterized through changes in surface wrinkle, roughness and contact angle. A dynamic range of surface properties were observed. Lastly, conductive fibrous membranes were fabricated with electrospinning. Two methods were utilized to spin conductive fibers including the incorporation of multi-walled carbon nanotubes (MWCNT) in polystyrene (PS) and the utilization of vapor phase polymerization (VPP) to chemically synthesize PPy on electrospun FeCl3/PS oxidant fibers. Properties including fiber morphology, thermal stability and conductivity were characterized. conductive polymers activation surface property 0548
3	The influence of surface properties on carbon fiber/epoxy matrix interfacial adhesion Zhuang, Hong 18 November 2008 (has links) The mechanical performance of composite materials depends not only on the matrix and the reinforcing fiber, but also to a great extent on the fiber/matrix interfacial adhesion. The focus of this work was to study carbon fiber surface chemical and physical properties and their effects on fiber/matrix adhesion. Untreated, commercially surface treated and oxygen plasma treated PAN based carbon fibers were used for study. XPS was used to determine fiber surface chemistry. A two-liquid tensiometric method was conducted to determine fiber surface energy and its dispersion and polar components. SEM was used to examine the fiber surface topography. Commercial surface treatment increased the carbon fiber surface oxygen content and fiber surface energy primarily in the polar component. An even higher level of fiber surface oxygen functionality and polar surface energy were achieved by oxygen plasma treatment. Oxygen plasma treatment also resulted in etching and pitting of AU-4 carbon fiber surface. Carbon fibers with varying surface properties were incorporated into epoxy matrices. Single fiber fragmentation tests were carried out to evaluate the strength as well as the temperature dependence and humidity durability of interfacial adhesion. Commercially treated carbon fibers which having a higher surface oxygen content and higher surface energy clearly produced superior interfacial adhesion, relative to untreated fibers. An even greater level of adhesion was achieved with oxygen plasma treated fibers. Fiber surface roughness improved durability under elevated temperature and relative humidity conditions. The presence of sodium on the fiber surface dramatically decreased durability at high relative humidity. / Master of Science surface property carbon fiber LD5655.V855 1995.Z483
4	Cellulosic nanocomposites with unique morphology and properties Lee, Jihoon 12 November 2010 (has links) Cellulose nanowhiskers reinforced poly(vinyl alcohol)(PVA) nanofiber web is successfully fabricated using electrospinning technique and the mechanical properties of the single electrospun fiber are measured using nanoindentation method. The morphology and mechanical properties of highly aligned electrospun fiber webs are investigated. It is found that the modulus and tensile strength of aligned webs are higher than those of isotropic electrospun fiber webs. Experimental results are compared with a longitudinal Halpin-Tsai model. Ice-templated(IT) cellulose microfibril porous foams are successfully fabricated via unidirectional freezing methods. The morphology and growth mechanism of IT surfaces are investigated successfully using cellulose microfibrils and hydrophillic substrates. By controlling the temperature gradient between cellulose microfibril suspensions and secondary freezing mediums, various surface structures including honey-comb like structures, ellipse-shape channel strcutures, fully developed multichannel structures are obtained. For the honey-comb like patterned surface, high contact angles are observed. On the other hand, for the layered patterned surface, anisotropic wetting properties are observed. Foam Electrospinning Cellulose microfibril Surface property Cellulose nanowhisker Nanocomposites (Materials) Nanostructured materials Nanofibers
5	The surface right / El Derecho de Superficie Del Risco Sotil, Luis Felipe 12 April 2018 (has links) This article addresses over the regulation of the surface right in the Peruvian Law along with its main points of contact with other important institutions in the field of real estate. The author points the evolution of this figure in the Peruvian legislation and determinates its legal nature and its characteristics, establishing its relation with the principle of real estate accession property and the implications of the transitional division that the surface generates. In other relevant aspects, the article addresses the ways of acquisition of such ownership, the role of inscription in the configuration of the surface, the reimbursement of the value of the buildings and the extinction of this property right. / Este artículo trata sobre la regulación del derecho real de superficie en el Derecho peruano y sus principales puntos de contacto con otras importantes instituciones en el ámbito inmobiliario. El autor aborda la evolución de dicha figura en la legislación peruana y determina la naturaleza jurídica y características del referido derecho, estableciendo su relación con el principio de accesión inmobiliaria y las implicancias de la división transitoria predial que genera la superficie. En otros aspectos relevantes, en este artículo se desarrollan las formas de adquisición de dicha titularidad, el papel de la inscripción en la configuración de la superficie, el reembolso del valor de las edificaciones y la extinción de este derecho real. Property surface Right surface Property real Estate Accession legal Surface surface Extinction Propiedad derecho De Superficie propiedad Superficiaria accesión Inmobiliaria superficie Jurídica extinción De Superficie
6	Aqueous Biphasic 3D Cell Culture Micro-Technology Atefi, Ehsan January 2015 (has links) No description available. Biomedical Engineering
7	From Macro to Nano : Electrokinetic Transport and Surface Control Pardon, Gaspard January 2014 (has links) Today, the growing and aging population, and the rise of new global threats on human health puts an increasing demand on the healthcare system and calls for preventive actions. To make existing medical treatments more efficient and widely accessible and to prevent the emergence of new threats such as drug-resistant bacteria, improved diagnostic technologies are needed. Potential solutions to address these medical challenges could come from the development of novel lab-on-chip (LoC) for point-of-care (PoC) diagnostics. At the same time, the increasing demand for sustainable energy calls for the development of novel approaches for energy conversion and storage systems (ECS), to which micro- and nanotechnologies could also contribute. This thesis has for objective to contribute to these developments and presents the results of interdisciplinary research at the crossing of three disciplines of physics and engineering: electrokinetic transport in fluids, manufacturing of micro- and nanofluidic systems, and surface control and modification. By combining knowledge from each of these disciplines, novel solutions and functionalities were developed at the macro-, micro- and nanoscale, towards applications in PoC diagnostics and ECS systems. At the macroscale, electrokinetic transport was applied to the development of a novel PoC sampler for the efficient capture of exhaled breath aerosol onto a microfluidic platform. At the microscale, several methods for polymer micromanufacturing and surface modification were developed. Using direct photolithography in off-stoichiometry thiol-ene (OSTE) polymers, a novel manufacturing method for mold-free rapid prototyping of microfluidic devices was developed. An investigation of the photolithography of OSTE polymers revealed that a novel photopatterning mechanism arises from the off-stoichiometric polymer formulation. Using photografting on OSTE surfaces, a novel surface modification method was developed for the photopatterning of the surface energy. Finally, a novel method was developed for single-step microstructuring and micropatterning of surface energy, using a molecular self-alignment process resulting in spontaneous mimicking, in the replica, of the surface energy of the mold. At the nanoscale, several solutions for the study of electrokinetic transport toward selective biofiltration and energy conversion were developed. A novel, comprehensive model was developed for electrostatic gating of the electrokinetic transport in nanofluidics. A novel method for the manufacturing of electrostatically-gated nanofluidic membranes was developed, using atomic layer deposition (ALD) in deep anodic alumina oxide (AAO) nanopores. Finally, a preliminary investigation of the nanopatterning of OSTE polymers was performed for the manufacturing of polymer nanofluidic devices. / <p>QC 20140509</p> / Rappid / NanoGate / Norosensor microsystem nanosystem microfluidic nanofluidic surface modification surface property electrokinetics model simulation material polymer thiol-ene microfabrication nanofabrication micromanufacturing nanomanufacturing breath sampling aerosol precipitation corona discharge electrostatic precipitation grafting chemistry click chemistry nanopore nanoporous membrane photolithography photopatterning photografting microfluidics nanofluidics oste OSTE+ OSTEmer lab-on-chip loc point-of-care poc biocompatibility diagnostics breath analysis fuel cell

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