An imaging system was developed to visualize Drop-on-Demand (DOD) inkjet drop formation and impaction on substrate over drop sizes and impaction speeds of the magnitudes encountered in applications of inkjet printing. Using a pulsed laser, a low-speed charge-coupled-device (CCD) camera, and signal generators, the imaging system based on flash photography was used to capture sharp images with a temporal resolution of 200 ns and a spatial resolution of 0.81 micron/pixel. First, the dynamics of DOD drop formation was studied experimentally. The effects of the driving signal, which controls the piezoelectric transducer that produces the pressure pulse to drive the liquid from the reservoir through the orifice, have been examined along with those of liquid properties. The main stages of DOD drop formation, including ejection and stretching of liquid, pinch-off of liquid thread from the nozzle exit, contraction of liquid thread, breakup of liquid thread into primary drop and satellites, and recombination of primary drop and satellites, are analyzed. A necessary condition for the recombination of the primary drop and satellite and the limit for liquid thread length without breakup during contraction are proposed. Second, using the visualization system coupled with a motorized stage, micron-drop impaction on a smooth substrate was investigated over a regime of We and Oh typical for inkjet printing applications. The results indicate that scaling of micron-drop impaction from millimeter-drop impaction, based on dimensionless numbers (Oh, We and cos ), is valid. The predictions of maximum spreading ratio by six existing models agree well with experimental values for high-We impaction, but not for low-We and low-contact-angle impactions; however, the model of Park et al. predicts well for high- and low-We impaction due to its inclusion of spontaneous spreading dissipation. Fingering and splashing do not occur in the micron drop impaction on either dry solid substrates or a pre-existing liquid layer. The drying time of a micron drop deposited on a substrate is less than one second and increases as the contact angle of the drop on the substrate increases.

A non-crosslinking approach that covalently bonds nitroxide polymer brushes onto the ITO substrates via surface-initiated atom transfer radical polymerization (ATRP) was develpoed. Since the indium tin oxide (ITO)-silane covalent bonding providesvery strong chemical bonds to adsorb the nitroxide polymer brushes on ITO, it prevents polymers from dissolving into electrolyte solvent and thus improves its electrochemical properties. Moreover, micro-contact printing technology was used to pattern nitroxide polymer brushes on an ITO surface for the potential application in microbatteries. The morphology of electrodes was observed by atomic force microscopy.The electrochemical properties of the cathode were also studies.

Archaeological conservation is the process by which conservators prevent deterioration of archaeological remains and provide insight into the nature of recovered material. This thesis examines the effect of digital technology upon the ethics of the conservation profession and upon the attitude of the lay-public towards archaeology. The ethical issues raised by the use of digital technology are discussed, particularly the ways in which these issues differ from those raised by traditional conservation methods. Technological advancements, particularly those occurring in the 20th century, changed the way artifacts are conserved and studied. Conservation arose out of a craft-restoration tradition and evolved into a profession which, in addition to necessary artistic and aesthetic considerations, uses a demonstrable scientific method in order to preserve artifacts. The creation of guidelines for practice and various codes of ethics is the turning point in this evolution, marking the point after which conservation became a scientific profession. Advances in computer technology have permitted the widespread use of devices such as 3-D scanners, digital CT scanners, and digital cameras in the conservation of archaeological artifacts. All of these pieces of equipment produced digital files which must be stored. Currently, the pace of technological change renders most data inaccessible within ten years, and data conservation problems such as storage, access, and file format have not been adequately addressed by the professional conservation community. There is a distinct lack of formal ethical guidelines concerning these issues; this thesis concludes that there is an extreme need for measured consideration before digital methods are used in archaeological conservation. The creation of high-fidelity replicas presents a problem for the museum audience. The public connects with artifacts on an emotional level which is altered when a replica is displayed instead of an original. Digital reconstructions abound in popular culture, heavily influencing public opinion, and often resulting in widespread misperception of the information which can be extracted from archaeological evidence. As a result, conservators of the future must be cautious when creating digital artifacts, and must be meticulously careful to make the nature of digital reconstruction clear to the audience, in order to avoid spreading misinformation.

1 x N optical power splitters using hybrid sol-gel glasses based on buried waveguide structure on silicon substrate were fabricated. The advantage over conventional ridge structures is the fact that Y branch of the splitters can be easily obtained with the buried structure using standard photo lithography processes. Now we can successfully make the width of Y branch of less of 1um. Proximity printing was used to define the waveguide trench on sol-gel films. Then burying the sol-gel glass into the trench to define waveguide core. Finally the waveguide was packaged for measurement after coating a sol-gel top cladding layer onto the guiding layer. The propagation losses of this waveguide device are 0.69 dB/cm and 0.70 dB/cm for TE and TM polarized lights. The coupling losses are 1.57 dB and 1.89 dB for TE and TM lights with a index contrast of 0.66 %. The insertion loss and the branching loss of the 1¡Ñ2 splitter are 5.7 dB and 0.3 dB¡Arespectively.

A series of novel metallic nanoparticle and suspension were developed and synthesized for ink-jet printing and spin coating applications. Organic components, such as alkanethiols and amines, were used as new capping agent design. The suspension was characterized by NMR, ESCA, TEM, SEM, EDS, TGA, DTG, DSC, TA-MS for chemical composition and three-dimension SAMs desorption.

iv ABSTRACT OPTIMIZATION OF METALIZATION IN CRYSTALLINE SILICON SOLAR CELLS Demircioglu, Olgu M. Sc. Department of Micro and Nanotechnology Supervisor : Prof. Dr. Rasit Turan Co-Supervisor : Assist. Prof. Dr. H. Emrah &Uuml / nalan August 2012, 103 pages Production steps of crystalline silicon solar cells include several physical and chemical processes like etching, doping, annealing, nitride coating, metallization and firing of the metal contacts. Among these processes, the metallization plays a crucial role in the energy conversion performance of the cell. The quality of the metal layers used on the back and the front surface of the cell and the quality of the electrical contact they form with the underlying substrate have a detrimental effect on the amount of the power generated by the cell. All aspects of the metal layer, such as electrical resistivity, contact resistance, thickness, height and width of the finger layers need to be optimized very carefully for a successful solar cell operation. In this thesis, metallization steps within the crystalline silicon solar cell production were studied in the laboratories of Center for Solar Energy Research and Application (G&Uuml / NAM). Screen Printing method, which is the most common metallization technique in the industry, was used for the metal layer formation. With the exception of the initial experiments, 6

The research discussed in this dissertation was conducted to understand drop formation of inkjet printing with inks containing polymer. Solutions containing a water soluble polymer, poly ethylene oxide (PEO), with different molecular weights and polydispersities were used as inks. A flash photographic technique was used to visualize the whole process of DOD drop formation of dilute polymer solutions. The effects of driving signal, frequency and liquid properties on drop speed, drop size, breakup time and the formation of satellites were studied in detail. The addition of PEO increases the shear viscosity at all molecular weights, but the change is small for dilute solutions. However, the addition of a small amount of PEO can have a significant effect on the DOD drop formation process, increasing breakup time, decreasing primary drop speed and decreasing the number of satellites in some cases. The effects depend on both molecular weight and concentration. At lower molecular weights (14k and 35k g/mol), the effect of PEO was small when the drop formation process for the dilute solution was compared with that of a Newtonian liquid having similar shear viscosity, and the effect of PEO was small even at concentrations large enough that the solution does not fall in the dilute regime. As molecular weight is increased, the effects of PEO on DOD drop formation increase significantly, and the effects of concentration become important. These effects are explained by the fluid elasticity which increases with increasing in molecular weight and concentration. When the liquid jets out of the nozzle, the polymer chains are stretched, and thus depart from their ideal coiled state. As a result, an elastic stress develops in the liquid column and resists capillarity-driven pinch off from the nozzle and is responsible for the decrease in drop speed and longer breakup time. DOD drop formation data were shown to correlate closely with effective relaxation time, proposed by Tirtaatmadja based on Rouse-Zimm theory. When driving voltage amplitude is 44.2 V, two important parameters (breakup time and primary drop speed) in DOD drop formation for solutions containing monodispersed PEO and aqueous solutions containing mixtures of monodispersed PEO were closely predicted by correlation equations involving effective relaxation time . A mixture rule was developed to calculate the relaxation time for mixtures of monodispersed PEO. However, for polydispersed PEO, effective relaxation time was based on viscous molecular weight since the molecular weight distributions of the polydispersed PEO were unknown. When breakup time was plotted versus effective relaxation time for 1000k g/mol PEO, the data did not lie on the same line as that for the 100k and 300k g/mol PEO. This is believed to be due to the molecular weight distributions of the polydispersed PEO. When more than one species are present, viscous average molecular weight does not adequately account for the long chain species making up the polymer sample. DOD drop formation dynamics is highly affected by the actuating waveform, including the driving voltage, waveform shape, and frequency. The effects of parameters (jetting frequency, voltage amplitude and the shape of waveform) characterizing the signal were investigated. The open time and first drop problem were also studied. Research in this dissertation gives a better understanding of DOD drop formation process of polymer solutions, which may lead to improvement of inkjet printing quality for a variety of industry inks and polymer micro scale deposition and patterning in large areas.

The research provided in this thesis focuses on the development of high-gain multilayer millimeter-wave (mm-Wave) antenna structures through additive inkjet printing fabrication processes. This work outlines the printing processes of thick dielectric films for use as printed radio frequency (RF) substrates and provides a proof-of-concept demonstration of the first fully-printed RF structures. Using the outlined processes, demonstrations of high-gain mm-Wave proximity-coupled patch array and Yagi-Uda array antennas are presented, achieving the highest realized gain within the 24.5 GHz ISM band for inkjet-printed antennas in literature.

This thesis provides investigation into the interaction between quartz lamp emitters and polyether ether ketone (PEEK) powder. Calculations and experiments concerning the conductivity and emissivity of the powder at various temperatures are performed. The thermal profile of the emitter on a flat powder bed is captured using thermal imaging. The effect of exposing a pile of powder to the emitter and the subsequent thermal gradient through the pile is measured and analyzed. Based on these results, ramifications for the application of these emitters to selective laser sintering (SLS) machines for processing high temperature polymers such as PEEK are discussed. / text

Digital Craft is a project that explores the interface between three-dimensional (3-D) computer technology and costume technology. I combine seasoned millinery techniques with modern methods of object construction and design to diversify the costume artisan’s toolbox and encourage practical and useful ways of moving between the virtual and physical world. Through a series of theoretical projects the dichotomy of modern artistic process is explored. The task of this thesis project is to explore the impact of 3-D imaging software on design and construction methods by applying them to the sculptural process of hat making. I collaborate with designers and technicians to develop methods of hat making for performance culminating in an exhibition presented at the University Co-op Cohen New Works Festival, April 2011. This research is applied to cultivate new methods of hat making, by exploring new media and expanding creative possibilities. Craft objects are created directly through the hand of the maker; it is thorough technique that the hand informs the craft object (Risatti, 108). Furthermore, the traditional notion of tools and craft objects is that they are conditioned, controlled and limited by the hands. In order to update and improve methods of object construction, this project will expand the traditional concept of craft, combining hands-on methods with machining. I hope to improve efficiency and decrease the cost of realizing authentic and original hat designs by exploring alternative digital spaces that can be used to communicate, develop and actualize ideas. / text