<p>Silver nanoparticles (AgNPs) are increasingly being integrated into a wide range of consumer products, such as air filters, washing machines, and textiles, due to their antimicrobial properties [1]. However, despite the beneficial applications of AgNPs into consumer products, it is likely that their use will facilitate the release of AgNPs into wastewater treatment plants, thereby possibly negatively impacting key microorganisms involved in nutrient removal. For this reason, it is important to characterize the effects of AgNPs in natural and engineered systems and to measure the antimicrobial effect of AgNPs on wastewater microorganisms. Polyvinyl alcohol coated AgNPs have already been linked to decreased nitrifying activity [2] and it is important to determine if AgNPs coated with other materials follow similar trends. Furthermore, it is likely that, with repeated exposure to AgNPs microbial communities could evolve and develop resistance to silver. Thus, a long-term effect of silver nanoparticle exposure could be a reduction of the efficacy of such products in a similar fashion to the development of microbial antibiotic resistance [3]. Therefore, it is critical that the impacts of these materials be ascertained in wastewater treatment systems to prevent long-term negative effects. </p><p>The objectives of this dissertation were to: 1) characterize the effect of several different AgNPs on the ammonia oxidizing bacterium (AOB) Nitrosomonas europaea and investigate possible mechanisms for toxicity, 2) test the effects of consumer product AgNPs on a wide range of heterotrophic bacteria, 3) evaluate the effects of AgNPs on bench scale wastewater sequencing batch reactors, and lastly 4) assess the impacts on microbial communities that are applied with AgNP spiked wastewater biosolids. </p><p>First, Nitrosomonas europaea was was selected because wastewater nitrifying microorganisms carry out the first step in nitrification and are known to be sensitive to a wide range of toxicants [4].The antimicrobial effects of AgNPs on the AOB N. europaea were measured by comparing nitrite production rates in a dose response assay and analyzing cell viability using the LIVE/DEAD® fluorescent staining assay. AgNP toxicity to N. europaea appeared to be largely nanoparticle coating dependent. While PVP coated AgNPs have shown reductions up to 15% in nitrite production at 20 ppm, other AgNPs such as gum arabic (GA) coated showed the same level of inhibition at concentrations of 2 ppm. The first mechanism of inhibition appears to be a post-transcriptional interference of AMO/HAO by either dissolved Ag or ROS, in treatments where membranes are not completely disrupted but nitrite production decreased (2 ppm GA AgNP and 2 ppm PVP AgNP treatments). The disruption of nitrification is dependent on AgNP characteristics, such as zeta potential and coating, which will dictate how fast the AgNP will release Ag+ and ROS production Finally, total membrane loss and release of internal cellular matter occur. </p><p>In order to test the effects of AgNP products available to consumers, simple bacterial toxicity tests were carried out on well-studied heterotrophic bacteria. A model gram-positive and gram-negative bacterium (B. subtilis and E. coli, respectively) was selected to assess any differences in sensitivity that may occur with the exposure to AgNPs. A third model gram-negative bacterium (P. aeruginosa) was chosen for its biofilm forming capabilities. In addition to testing pure nanoparticles, three silver supplements meant for ingestion, were randomly chosen to test with these three bacteria. Growth curve assays and LIVE/DEAD staining indicate that the consumer product AgNPs had the most significant inhibition on growth rates, but not membrane integrity. Overall, P. aeruginosa was most negatively affected by all AgNPs with nearly 100% growth inhibition for all 2 ppm AgNP treatments. TEM imaging also confirmed cell wall separation in P. aeruginosa and internal density differences for E. coli. The effects on B. subtilis, a gram-positive bacterium, were not as severe but toxicity was observed for several AgNPs at concentrations greater than 2 ppm. Citrate AgNPs appeared to have the most impact on membrane integrity, while other mechanisms such as internal thiol binding might have been at work for other AgNPs. </p><p>The effects of varying concentrations of pure AgNPs on complex microbial wastewater reactors are currently being tested. Eight bench-scale sequencing batch reactors were set up to follow the typical "fill, react, settle, decant, idle" method with an 8 hour hydraulic retention time and constant aeration. Reactors were fed synthetic wastewater and treatment efficiency is measured by monitoring effluent concentrations of COD, NH4+, and NO3-. The reactors were seeded with 500 mL of activated sludge from a local wastewater treatment plant. After reaching steady state, the reactors were spiked with 0.2 ppm gum arabic and citrate coated AgNPs. Treatment efficiency was monitored and results showed significant spikes and ammonia and COD immediately following the first spike, but the microbial community appeared to adapt for future AgNP spikes. Microbial community analysis (terminal restriction fragment length polymorphism) showed confirmed this hypothesis. </p><p>Overall, this dissertation asserts that by examining AgNP coating type, Ag+ dissolution rates and Stern layer surface charge, it may be possible to predict which AgNPs may be more detrimental wastewater treatment, but not all AgNPs will have the same effect. The results obtained herein must be expanded to other types of AgNPs and microorganisms of ecological importance.</p> / Dissertation

DNA has been widely studied in a variety of solvents. The majority of these solvents consist of either aqueous or organic components. The presence of ions or salts in these solvents can further alter DNA properties by changing the melting point or helical structure. The size, charge, and concentration of these additional components can all affect the behaviour of DNA. A new class of solvents, known as ionic liquids have recently gained popularity. Ionic liquids are comprised of entirely of ions and can be liquid at room temperature. Due to their low volatility and ability to dissolve both polar and non-polar substances, they are generating high levels of interest as ‘green solvents’. Although the interaction between DNA and ionic liquids has been characterized, the potential of this interaction is still being studied. It was discovered that when DNA mixed with DNA intercalating dyes was added to ionic liquids, there was a large reduction in fluorescence. Although this fluorescence drop was believed to occur to removal of the dye molecule from the helix, the strength of this interaction has not been researched. In this thesis, the interaction between different intercalating dyes and different ionic liquids was evaluated. We reasoned that perhaps the difference in interaction could be used as a method of separating the DNA-dye complex, which has previously never been accomplished. For example, it has been established that both DNA and cationic dyes have an affinity for ionic liquids. The relative strength of this affinity is undetermined, as well as the comparison to normal aqueous mediums. Although ionic liquids can drastically alter the stability of the DNA duplex by either raising or decreasing the melting point depending on the ionic liquid chosen, we found that the DNA actually has a higher affinity for the aqueous phase. Conversely, intercalating dyes prefer to partition into the ionic phase. The relative affinities of the two components are strong enough for their respective phases that the complex can be split apart and each component can be extracted, allowing for separation of the two.

Elongated nanostructures have attracted a great deal of interest due to unique optical, electrical and physical properties. In particular, silver nanowires and nanobeams have proven to be top contenders for a variety of applications. Due to their nano-sized dimensions, however, electrical access to individual nanowires is difficult and expensive. Here, a simple and economical procedure was designed to electrically contact small elongated structures using common facilities available at most universities. A common lithographic procedure is used to pattern gold pads and electrodes on top of nanowires already dispersed on a substrate. This process is tested by first characterizing, using a 4-point-probe measurement, a novel nanobeam created by fusing silver nanodisks. The resistivity of the nanobeams was found to be as low as 2.7x10^−8 Ω·m, which is only slightly above that of bulk silver. These measurements corroborate modeling done by another group that the nanodisks align to create a nearly continuous crystal rather than disjointed grains. In the second application, Joule-heating was used to actualize a reliable weld between silver nanowires synthesized using the polyol method. The nanowires were situated in series between two metal pads, and a procedure was designed to use electrical current to break down intermediate layers without destroying the nanowires themselves. In the last enterprise, individual silver nanowires were isolated between two gold pads and then using the same electrical recipe used for welding nanowires, the contact resistance was reduced to a negligible portion of its original value. It was found that due to the reduction in contact resistance, the 2-point-probe resistivity of the nanowire was similar to those conducted using 4 probes. The invented procedure can thus allow accurate resistivity measurements of individual metal nanowires to be done with only 2 contacts rather than 4, thereby simplifying contact fabrication and allowing appropriate contacts to be deposited on nanowires as short as 4 μm using standard photolithography.

Los nanotubos de carbono (CNTs, carbon nanotubes) son moléculas tubulares cuyo diámetro es de escala nanométrica y cuyas paredes están formadas por capas monoatómicas de carbono. Su estructura en combinación con su morfología unidimensional confieren unas propiedades muy especiales que hacen de los CNTs un material muy atractivo para el desarrollo de amplia gama de aplicaciones. En el marco de la micro y nanotecnología, los CNTs son un material muy prometedor para la fabricación de dispositivos y sistemas, por ejemplo, en el campo de la nanoelectrónica, los sensores o los sistemas nanoelectromecánicos (NEMS, del inglés nanoeletcromechanical systems). Sin embargo, dado que aún no se han estandarizado procesos para su síntesis controlada, su integración sigue siendo un reto. Esta tesis fue concebida para avanzar en la integración CNTs en distintos micro y nanodispositivos. El trabajo realizado aborda la ingeniería de procesos, el diseño de dispositivos, y la fabricación y la caracterización de esos dispositivos. Se plantearon dos objetivos principales. El primero fue el adquirir el conocimiento de la síntesis de CNTs mediante la técnica de depósito químico desde fase vapor por calentamiento rápido (RTCVD, rapid termal chemical vapour deposition) y desarrollar procesos para la síntesis de CNTs de una estructura concreta y en una determinada configuración. El segundo objetivo fue el desarrollo de procesos de fabricación para la integración de CNTs en dispositivos basados en diferentes tecnologías y con diferentes funcionalidades. A pesar de la problemática inherente al desarrollo de los procesos tecnológicos, se cumplieron la mayor parte de los objetivos inicialmente propuestos. La síntesis de CNTs se logró mediante catalizadores convencionales (principalmente hierro y níquel) y mediante catalizadores no convencionales (platino). Cabe destacar que los procesos de síntesis de CNTs fueron estandarizados a nivel de obleas de 4 pulgadas, tanto para configuraciones de baja densidad de CNTs monocapa (SWCNTs, single-walled carbon nanotubes) como para configuraciones de alta densidad de CNTs multicapa (MWCNTs, multi-walled carbon nanotubes), ya que la síntesis tradicionalmente se realiza a nivel de chip. En cuanto a la integración de CNTs, se optimizaron dos procesos principalmente. Por un lado, se desarrolló una tecnología para la fabricación masiva en oblea de transistores basados en SWCNTs. Mediante esta tecnología se logró la fabricación de 10.000 transistores funcionales en obleas de 4 pulgadas. Por otro lado, se integró gran densidad de MWCNTs sobre los electrodos metálicos de dispositivos que habían sido demostrados para detección bio-electroquímica. La caracterización de estos electrodos demostró que esta actualización de la tecnología mejora el rendimiento de la fabricación y las características electroquímicas de los electrodos respecto a los diseños anteriores. Los resultados presentados en esta tesis son un paso adelante para la Integración a muy gran escala (VLSI, very large system integration) de CNTs. Los procesos que se desarrollaron son de interés en el campo de la nanoelectrónica, en el campo de la bio-sensores electroquímicos, para la fabricación de dispositivos optoelectrónicos y para la fabricación de NEMS. / Carbon nanotubes (CNTs) are tubular molecules which diameters may be smaller than one nanometre and which walls are formed of single carbon atom layers that are arranged in a honey comb lattice. Because of their one dimensional aspect ratio and properties, which are conferred by their structural arrangement, CNTs are a very attractive material for a wide range of applications. In the frame of micro- and nanotechnology, CNTs have been demonstrated to be very promising for the fabrication of devices and systems for nanoelectronics, sensors or nanoelectromechanical systems (NEMS). However, standardised processes for their fully controlled synthesis and their successful integration into those systems are still challenging. This thesis was conceived to advance on the wafer scale integration of CNTs into micro- and nanodevices. Performed work dealt with process engineering, device design, device fabrication and device characterization. Two major goals were pursued: (i) to acquire the knowhow on the synthesis of CNTs by rapid thermal chemical vapour deposition (RTCVD) to develop recipes to synthesize certain in structure CNTs and certain in morphology CNT arrays, and (ii) the wafer scale integration of CNTs into devices with different functionalities and technological processes by conventional fabrication steps. Despite the inherent problematic of the technological process developments, most of the initially foreseen goals were fulfilled. The CNT synthesis was achieved by conventional (mainly iron and nickel) and by nonconventional (platinum) catalyst materials. It is remarkable how the CNT RTCVD synthesis processes were standardized at 4 inch wafer scale for either low density of single-walled (SW) CNT arrays or for dense, vertically aligned multi-walled (MW) CNT arrays, since the CNT synthesis is normally performed at chip level. Regarding the wafer scale integration of the CNTs, two main processes were optimised. On the one side, SWCNTs were integrated in the fabrication of CNT-FETs. This technology resulted in the fabrication of 10,000 functional CNT-FETs on 4 inch wafers in a sole fabrication process. Later on, the technology was upgraded for the fabrication of passivated CNT-FET devices for electrochemical sensing. On the other side, dense arrays of MWCNTs were integrated into devices based on metallic electrodes that had previously been demonstrated for bio-electrochemical sensing. These electrodes were demonstrated to improve the fabrication yield and the electrochemical characteristics with respect to the previous designs. Presented in this thesis results are a step forward to the Very Large Scale Integration (VLSI) of CNTs. The developed processes are of interest in the field of nanoelectronics, in the field of bio-electrochemical sensing, for the fabrication of optoelectronic devices and for the fabrication NEMS.

<p>Nanostructures are being intensely studied due to unusual material properties and simple scaling concerns in the microelectronics industry. Fabricating useful nano-scale structures and devices, either by arranging existing nanoparticles such as carbon nanotubes or by manipulating bulk materials into nanometer-scale geometries, is a challenging prospect. One promising approach is to generate a nanometer-scale pattern and transfer that geometry into another material. The research described in this dissertation concerns the fabrication of nanometer-scale patterns, by Atomic Force Microscope-based methods and Electron Beam Lithography, on planar surfaces and the transfer of those patterns into functional materials. Differences in surface energy were used to guide the growth of bulk conducting polymer along predefined nano-scale patterns. Carbon nanotubes were assembled into an ordered and continuous material with no guidance and used to lithographically write silicon oxide nanopatterns on a silicon surface. Finally, the two previous projects were combined, and surface energy patterns were used to guide the deposition of dense carbon nanotube bundles along a planar substrate.</p> / Dissertation

Compared to China and southeast Asian countries, corporations of traditional industry in Taiwan are more and more uncompetitive in terms of cost of human and manufacture. The application of nanotechnology is an opportunity that can adds product value and upgrade industry in the traditional industry in Taiwan. Traditional industry corporations face stable environment and long technology life and manufacture mainly, so they have less need for new technology and are lacking in experience of commercializing technology. The appearance of nanotechnology will affect Taiwan traditional industry¡¦s competitive advantage and make it without other choice but to face the emerging technology. Corporations must combine nanotechnology with its domain technology. Because it is different from the general process of commercializing technology adapted to the used technology, traditional industry corporations¡¦ processing the technology commercialization will face different problems and need different help. The methodology of this research includes case study, secondary data collection approaches, and interviews of corporate managers and related experts. Then we integrate the three parts of the process of technology commercialization, the plan of National Science and Technology Program for Nanoscience and Nanotechnology for traditional industry, and Industrial Technology Research Institute¡¦s (ITRI) guidance and promotion project into the model of nanotechnology commercialization of traditional industry in Taiwan. In this research, we find that government must actively facilitate nano-industry cluster, process nano-fundamental research and train people of talent to build a complete nano-industry environment. In the early stage of technology commercialization, the key point is how to bring in nanotechnology. The traditional industry corporations must cooperate with the modifiers and connectors, process technology transfer and then combine nanotechnology and their domain technology together. Finally, they could introduce their new products to the market.

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 98-102).

Thesis (M.S. in Applied Physics)--Naval Postgraduate School, December 2003. / Thesis advisor(s): Young W. Kwon, James H. Luscombe. Includes bibliographical references (p. 53-57). Also available online.

Thesis (Ph.D.)--University of Central Florida, 2008. / Adviser: Hyoung Jin Cho. Includes bibliographical references (p. 105-117).

The control and manipulation of infrared (IR) radiation beyond the capabilities of natural materials using silicon carbide (SiC), metamaterials, or a combination thereof, is presented. Control is first demonstrated using SiC, a polar crystal that exhibits a dielectric permittivity less than zero in the mid-IR range, through the excitation of tightly confined surface phonon-polaritons (SPPs), thus enabling a multitude of applications not possible with conventional dielectrics. Optimal, or critical coupling to SPPs is explored in SiC films through Otto-configuration attenuated total reflection. One practical application based on Otto-coupled SPPs is presented: IR refractive index sensing is shown for three pL-scale fluid analytes. It is then demonstrated that when two SiC films are brought to a few-micron separation, IR radiation can excite surface modes that possess phase velocities near the speed of light, a property required for efficient table-top particle accelerators. Metamaterials are engineered with subwavelength structure and possess optical properties not found in nature. Two such metamaterials will be introduced: metal films perforated with arrays of rectangular holes display the ability to control IR light polarization through spoof surface plasmon excitation, and metal/dielectric multilayers patterned with subwavelength-pitch corrugations display frequency-tunable, wide-angle, perfect IR absorption. Two experiments, which have implications in polarization control and thermal emission, combine the benefits of SiC with those of metamaterials: extraordinary optical transmission and absorption are observed in SiC hole arrays, and the design of individual SiC antennas permits the control of the bulk metamaterial responses of impedance and absorption/emission. Finally, a new optical beamline based on Fourier transform IR spectroscopy was designed, built, characterized, and implemented, serving as the major experimental objective of this dissertation. The novel beamline, which confines radiation to a 200-micron diameter and enables angle-dependent IR spectroscopy, was verified using multiple metamaterial structures. / text