Pulsed laser ablation ¡]PLA¡^in single shot on polycrystalline Ti thin foil ca. 20

This research has discussed the graphene growth mechanism and the achievement, the main purpose is to try the best method to grow graphene which is large size, uniform, and continue. The main issue is about growth and characterizations in full text which is separated by thermal annealing 6-H SiC(001) and chemical vapor deposition on the copper foil to grow graphenen. For instances, to adjust the growth parameters and the growth methods to get graphene and to control the quality, to analysis the number of layers, to research the characterizations during growth process, and to find the better transfer method are all the important focus in this paper. The morphology of samples is studied by SEM, AFM, STM, OM and so on, further the thickness of graphene layers can be observed by AFM and STM. Due to the limit of instruments, the thickness of graphene layer (~0.35 nm) and the thickness of 6-H SiC(001) steps (~1.5 nm) are not easy to observe actually. Raman spectroscopy is the main analysis tool I have employed, it is the fast way to calculate the number of layers (G, 2D band). In addition, Raman scattering is able to know the information of electronic structure variation (2D band), to investigate the stress which is caused by substrate and to estimate the quality of graphene (D, G band). Finally, I take chemical vapor deposition to grow graphenen on the copper foil. Sample is successfully transferred onto SiO2, and the number of graphene layers is estimated to be about two and the structure is AA stacking from these data. The data also shows the graphene is large size, uniform, and continue.

Thesis (M.M.S.E.)--University of Delaware, 2009. / Principal faculty advisor: John W. Gillespie, Dept. of Materials Science. Includes bibliographical references.

Thesis (M.S.)--University of Michigan, 1961.

Thesis (M.S.)--University of Michigan, 1961.

Doctor of Philosophy / Department of Mechanical and Nuclear Engineering / Douglas S. McGregor / The 3He gas shortage for neutron detection has caused an increase in research efforts to develop viable alternative technologies. 3He neutron detectors cover areas ranging from 10–1000 cm2 in cylindrical form factors and are ideal for many nuclear applications due to their high intrinsic thermal neutron detection efficiency (> 80%) and gamma-ray discrimination (GRR ≤ 1 x 10-6) capabilities. Neutron monitoring systems for nuclear security applications include Radiation Portal Monitors (RPM’s), backpack, briefcase, and hand-held sensors. A viable replacement technology is presented here and compares three neutron detectors, each with different neutron absorber materials, to current 3He standards. These materials include Li and/or B silica aerogels, LiF impregnated foams, and metallic Li foils. Additionally, other neutron absorbing materials were investigated in this work and include LiF coated Mylar, B foils, BN coated carbon foam, and BN coated plastic honeycomb. From theoretical calculations, the Li foil material showed the greatest promise as a viable 3He alternative, thus a majority of the research efforts were focused on this material. The new neutron detector was a multi-wire proportional counter (MWPC) constructed using alternating banks of anode wires and 95% enriched 6Li foils sheets spaced 1.63 cm apart. In total, six anode banks and five layers of foil were used, thus an anode wire bank was positioned on each side of a suspended foils. Reaction products from the 6Li(n,α)3H reaction were able to escape both side of a foil sheet simultaneously and be measured in the surrounding gas volume concurrently. This new concept of measuring both reaction products from a single neutron absorption in a solid-form absorber material increased the intrinsic thermal neutron detection efficiency and gamma-ray discrimination compared to coated gas-filled detectors. Three different sizes of Li foil MWPC neutron detectors were constructed ranging from 25–1250 cm2 and included detectors for RPM’s, backpacks, and hand-held systems. The measured intrinsic thermal neutron detection efficiency of these devices was approximately 54%, but it is possible to exceed 80% efficiency with additional foils. The gamma-ray discrimination abilities of the detector exceeded 3He tubes by almost three orders of magnitude (GRR = 7.6 x 10-9).

This thesis contains an experimental campaign on the practical implementation of oscillating-foil technologies. It explores two possible engineering applications of oscillating-wings: thrust-generation, and energy-extraction. The history of, benefits of, and difficulties involved in the use of oscillating-foils is discussed throughout. Many existing technologies used for thrust generation and hydrokinetic energy extraction are based on rotating blades or foils, which have evolved over decades of use. In recent years, designs that use oscillating-foils, with motions analogous to the flapping of a fish’s tail or a bird’s wing, have shown increased hydrodynamic performance compared to the traditional rotary technologies. However, these systems are complex, both in terms of the governing unsteady fluid dynamics, and the methods by which kinematics are prescribed. Simply put, system complexity and cost need to be reduced before these devices see wide-spread use. For this reason, the work contained within this thesis explores possible methods of reducing the complexity of oscillating-foil systems in an effort to contribute to their development. For thrust-generation applications, this entailed using flexible foils to create passive pitching kinematics. This was parametrically studied by testing foils of different structural properties under a range of kinematics. The results suggested that properly tuning the flexibility of the foil could enhance both the thrust generation, and the efficiency of the propulsive system. With respect to energy-harvesting applications, the reliability of a novel fully passive turbine was assessed. The prototype tested had no active control strategy, and the degreesof-freedom were not mechanically linked, greatly simplifying the design. The prototype was subjected to real-world conditions, including high turbulence levels and the wake of an upstream turbine, and displayed robust performance in most conditions. In both applications, the hydrodynamic performance of the oscillating-wings was directly measured, and particle image velocimetry was used to observe the flow topology in the wakes and boundary layers of the foils. The vortex and stall dynamics were highlighted as key flow features, and are studied in detail. / Graduate

The use of thin-film techniques for the fabrication of microfluidic devices has gained attention over the last decade, particularly for three-dimensional channel structures. The reasons for this include effective use of chip volume, mechanical flexibility, dead volume reduction, enhanced design capabilities, integration of passive elements, and scalability. Several fabrication techniques have been adapted for use on thin films: laser ablation and hot embossing are popular for channel fabrication, and lamination is widely used for channel enclosure. However, none of the previous studies have been able to achieve a strong bond that is reliable under moderate positive pressures. The present work aims to develop a thin-film process that provides design versatility, speed, channel profile homogeneity, and the reliability that others fail to achieve. The three building blocks of the proposed baseline were fifty-micron poly(methyl methacrylate) thin films as substrates, channel patterning by laser ablation, and device assembly by thermal-fusion bonding. Channel fabrication was characterized and tuned to produce the desired dimensions and surface roughness. Thermal bonding was performed using an adapted mechanical testing device and optimized to produce the maximum bonding strength without significant channel deformation. Bonding multilayered devices, incorporating conduction lines, and integrating various types of membranes as passive elements demonstrated the versatility of the process. Finally, this baseline was used to fabricate a droplet generator and a DNA detection chip based on micro-bead agglomeration. It was found that a combination of low laser power and scanning speed produced channel surfaces with better uniformity than those obtained with higher values. In addition, the implemented bonding technique provided the process with the most reliable bond strength reported, so far, for thin-film microfluidics. Overall, the present work proved to be versatile, reliable, and fast, making it a good candidate to reproduce several on-chip functions. Future work includes implementing thick-substrate bonding techniques to further improve the process and decrease energy requirements.

Boats have a rich history, evolving in shape and purpose. From ancient logboats to modern superyachts, their design depends on their intended use. Among personal watercraft, such as yachts and motorboats, there are various types like fishing boats and day cruisers. Runabout boats are popular today for leisure. They are fast, agile, and versatile, originating in the 1920s with wooden bodies. Modern Runabout boats carry 4-8 people, lack a cabin, and are favored by casual boaters.  One of the latest trends within boating is the usage of hydrofoils, a hydrofoil is a wing-like shape that lifts a boat out of the water, reducing drag on the boat. Flighter is a new company intending on creating a new concept for a hydro foiling boat that is meant for transportation. They want a boat that is agile and has some multifunctional aspects allowing it to be used by a wider user group.  The following project is a design project focused on the conceptual interior design of Flighters new boat where the goal is to create an interior that fits with Flighters agenda. The concept developed through the project uses a rail system to create modular seating that allows the user to modify the boat to the current needs. There is also a multifunctional sofa in the back allowing for extra storage and seating if needed.

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