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Homogenization studies for optical sensors based on sculptured thin filmsJamaian, Siti Suhana January 2013 (has links)
In this thesis we investigate theoretically various types of sculptured thin film (STF) envisioned as platforms for optical sensing. A STF consists of an array of parallel nanowires which can be grown on a substrate using vapour deposition techniques. Typically, each nanowire has a diameter in the range from ~ 10-300 nmwhile the film thickness is ~<1μm. Through careful control of the fabrication process, both the optical properties and the porosity of the STF can be tailored to order. These abilities make STFs promising for optical sensing applications, wherein it is envisaged that the material to be sensed infiltrates the void region in between the parallel nanowires and hence changes the optical properties of the STF. Various homogenization formalisms can be used to estimate the constitutive parameters of the infiltrated STFs. In this thesis two different homogenization formalisms were used: the Bruggeman formalism (extended and non–extended versions) and the strong-permittivityfluctuation theory (SPFT). These were used in investigations of the following optical–sensing scenarios: (i) Electromagnetic radiation emitted by a dipole source inside an infiltrated chiral STF. The effects of using the extended Bruggeman homogenization formalism, which takes into account the nonzero size of the component particles,were studied. (ii) Surface–plasmon– polariton waves on ametal–coated, infiltrated columnar thin film. The influences of using the extended SPFT formalism, which takes into account the nonzero size of the component particles and their statistical distributions, were explored. (iii) A metal-coated infiltrated chiral STF which supports both surface-plasmon-polariton waves and the circular Bragg phenomenon. The possibility of using in parallel both surface-plasmon-polariton waves and the circular Bragg phenomenon was investigated using the non–extended Bruggeman formalism. Our numerical studies revealed that the design performance parameters of the infiltrated STF are bode well for these optical–sensing scenarios. The use of inverse Bruggeman formalism was also investigated: this was found to be problematic in certain constitutive parameter regimes, but not those for optical–sensing scenarios considered in this thesis.
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A HEURISTIC APPROACH TO INSPECTION OF SCULPTURED SURFACES USING DATA LOCALIZATIONJOSHI, MANDAR 08 October 2007 (has links)
No description available.
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The Early Post-restoration Population Dynamics and Community Interactions of a Former Agricultural Field in the Carolinian Canada Life ZoneInlow, Katelyn J. January 2010 (has links)
Monitoring ecological restoration at the community scale provides insight into how the population dynamics and community interactions are progressing through time in comparison to a restoration’s goals and reference conditions. This study monitored the early post-restoration dynamics of a sand plain located in the Carolinian Canada ecozone called Lake Erie Farms. The restoration consisted of restoring three habitats via sculptured seeding: a mesic forest, oak woodland, and sand barren. The hypothesis of this study is that the restoration efforts have established population dynamics and community interactions consistent with successional patterns expected from comparative literature. Community ecology, directed succession, and alternative stable states are the underlying theories that provided a conceptual and theoretical lens from which to study the objectives and hypothesis.
To gain insight into the community dynamics at Lake Erie Farms the vegetation abundance, seed abundance and viability of the seedbank, seed viability of the 6 most dominant species (3 most dominant native species & 3 most dominant weedy species), and soil moisture & pH were monitored. The analysis was conducted using a RMANOVA of a nested design (P > 0.001, 0.01 and 0.05) to compare the variables in relation to the site (i.e. the sum of all the quadrats), the restoration treatment nested within the site, the field nested within the site, the transect nested within the restoration treatment and the quadrat nested within the restoration treatment.
The significant findings of this study include: i) the restoration treatments are producing similar results as those expected from the literature, though there is evidence of the sculptured seeding treatment accelerating the successional stage at Lake Erie Farms compared to abandoned agricultural fields in similar ecosystems because of the presence of later-successional species; ii) the control areas are less diverse than each of the restoration units (P>0.05); and iii) the soil moisture among the treatments is beginning to diverge into the desired restoration units.
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The Early Post-restoration Population Dynamics and Community Interactions of a Former Agricultural Field in the Carolinian Canada Life ZoneInlow, Katelyn J. January 2010 (has links)
Monitoring ecological restoration at the community scale provides insight into how the population dynamics and community interactions are progressing through time in comparison to a restoration’s goals and reference conditions. This study monitored the early post-restoration dynamics of a sand plain located in the Carolinian Canada ecozone called Lake Erie Farms. The restoration consisted of restoring three habitats via sculptured seeding: a mesic forest, oak woodland, and sand barren. The hypothesis of this study is that the restoration efforts have established population dynamics and community interactions consistent with successional patterns expected from comparative literature. Community ecology, directed succession, and alternative stable states are the underlying theories that provided a conceptual and theoretical lens from which to study the objectives and hypothesis.
To gain insight into the community dynamics at Lake Erie Farms the vegetation abundance, seed abundance and viability of the seedbank, seed viability of the 6 most dominant species (3 most dominant native species & 3 most dominant weedy species), and soil moisture & pH were monitored. The analysis was conducted using a RMANOVA of a nested design (P > 0.001, 0.01 and 0.05) to compare the variables in relation to the site (i.e. the sum of all the quadrats), the restoration treatment nested within the site, the field nested within the site, the transect nested within the restoration treatment and the quadrat nested within the restoration treatment.
The significant findings of this study include: i) the restoration treatments are producing similar results as those expected from the literature, though there is evidence of the sculptured seeding treatment accelerating the successional stage at Lake Erie Farms compared to abandoned agricultural fields in similar ecosystems because of the presence of later-successional species; ii) the control areas are less diverse than each of the restoration units (P>0.05); and iii) the soil moisture among the treatments is beginning to diverge into the desired restoration units.
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Fabrication and Characterization of Sculptured Thin Silver FilmsGustafson, Johan January 2013 (has links)
In this work samples with silver nanocolumnar structures were successfully fabricated by glancingangle deposition. From SEM investigations of the samples it is concluded that distinct andseparated nanocolumns can be grown without pre-patterned substrates using this method (givensuitable deposition conditions). The sample that exhibits the most distinct and well separatedcolumns was modelled using HFSS with optical properties of silver in nanocolumns obtained bymeasurements on the samples grown by glancing angle deposition, thin enough to not havedeveloped columns. From numerical calculations it was shown that the unit cell arrangement of thecolumns has a large influence on the optical characteristics. It was found that a diamond-like unitcell designed as two identical square lattices shifted by half the lattice spacing in one direction and2-1/2 times the lattice spacing of the other direction gives the best and a fair agreement to theexperimental ellipsometry data. Based on this model calculations were made to determine thewavelength dependent average local current exhibited in the columns as well as the currentdensity. This study showed the occurrence of broadbanded plasmon resonances of longitudinalmode at λ=1363 nm and of transverse mode at λ=545 nm. It was also shown that the opticalcharacteristics are strongly polarization dependent as is expected for such anisotropic samples.
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Growth and Characterization of Al1-xInxN NanospiralsEkeroth, Sebastian January 2013 (has links)
In this work columnar nanospirals of AlInN were grown on top of TiN-coated sapphire substrates by magnetron sputtering. A variety of samples with different growth parameters were fabricated and investigated. The main objectives in this work were to optimize the degree of circular polarization and to control the active wavelength region for where this polarization effect occurs. Attempts were made to achieve a high degree of circular polarization in both reflected and transmitted light. It is shown that for reflected light it is possible to achieve a high degree of circular polarization within the visible wavelength regions. For transmitted light the concept of achieving circularly polarized light is proven.
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Web Based Automatic Tool Path Planning Strategy for Complex Sculptured SurfacesPatel, Kandarp 07 June 2010 (has links)
Over the past few years, manufacturing companies have had to deal with an increasing demand for feature-rich products at low costs. The pressures exerted on their existing manufacturing processes have lead manufacturers to investigate internet-based solutions, in order to cope with growing competition. Today, the availability of powerful and low cost 3D tools, along with web-based technologies, provides interesting opportunities to the manufacturing community, with solutions directly implementable at the core of their businesses and organizations.
The wooden sign is custom i.e. each sign is completely different from each other. Mass Customization is a paradigm that produces custom products in masses. A wooden sign is custom in nature, and each sign must be completely different from another. Although process planning for mass customized products is same, the tool path required to CNC machine the custom feature varies from part to part. If the tool path is created manually the economics of mass production are challenged. The only viable option is to generate the tool path automatically; furthermore, any time savings in the tool path lead to better profit margins.
This thesis presents the automatic web-based tool path planning method for machining sculptured wooden sign on 3 axis Computer Numerical Controlling (CNC) Machines using optimal and cost-effective milling cutters. The web-based tool path planning strategy is integrate with web-based CAD system to automatically generate tool paths for the CAD model using optimal cutter within desired tolerances. The tool path planning method is divided into two parts: foot print (path along which cutter moves) and cutter positioning. The tool path foot print is developed during design stage from the CAD model based on the type of surface to be machined. The foot print varies from part to part which facilitates the mass customization of wooden sign. After designing foot print, the foot print is discretized into points and the gouge-free cutter position at each of these points is found using "Dropping Method". The Dropping Method where cutter is dropped over the work piece surface, and the highest depth at which cutter can go without gouging the surface is calculated. This is repeated for all the position along the foot print. This tool path planning strategy is developed for ball nose, flat-end and radiused end milling cutter for machining wooden sign.
The tool path generated using this method is optimized for machining time, tool path generation time and final surface finish. The bucketing technique is developed to optimize tool path generation time, by isolating the triangles which has possibility of intersection at particular position. The bucketing Technique reduced the tool path computation by 75 %, and made tool path generation faster. The optimal cutter selection algorithm is developed which selects best cutter for machining the surface based on the scallop height and volume removal results. The radiused end milling cutter results in highest volume removal which results in lower machining time compared to ball nose end milling cutters, but the scallop heights is higher. However, the scallop height in the radiused end milling cutter is higher only in few regions which reduces the final surface finish. For a sign, it was found around the boundary of logo, outline of lettering, interface of border and background. Thus, in order to achieve higher surface finish and lower machining time, a separate tool path is developed using "Pencil Milling Technique" which will remove the scallops from the regions that was inaccessible by radiused end mills. This tool path with the smaller cutter will move around the boundary of logo and lettering, and clean-up all the scallops left on the surface.
The designed tool path for all the three cutters were tested on maple wood and verified against the actual Computer Aided Design model for scallop height and surface finish. The numerical testing of tool path was carried out on a Custom Simulator, ToolSim and was later confirmed by actually machining on a 3 axis CNC machine. The same sign was machined with variety of milling cutters and the best cutter was selected based on the minimum scallop and maximum volume removal. The results of the experimental verification show the method to be accurate for machining sculptured sign. The average scallop height in a machined using 1/8 th inch radiused end milling cuter and using Pencil tool path on the machined surface is found to be 0.03989 mm (1.5708 thou).
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Web Based Automatic Tool Path Planning Strategy for Complex Sculptured SurfacesPatel, Kandarp 07 June 2010 (has links)
Over the past few years, manufacturing companies have had to deal with an increasing demand for feature-rich products at low costs. The pressures exerted on their existing manufacturing processes have lead manufacturers to investigate internet-based solutions, in order to cope with growing competition. Today, the availability of powerful and low cost 3D tools, along with web-based technologies, provides interesting opportunities to the manufacturing community, with solutions directly implementable at the core of their businesses and organizations.
The wooden sign is custom i.e. each sign is completely different from each other. Mass Customization is a paradigm that produces custom products in masses. A wooden sign is custom in nature, and each sign must be completely different from another. Although process planning for mass customized products is same, the tool path required to CNC machine the custom feature varies from part to part. If the tool path is created manually the economics of mass production are challenged. The only viable option is to generate the tool path automatically; furthermore, any time savings in the tool path lead to better profit margins.
This thesis presents the automatic web-based tool path planning method for machining sculptured wooden sign on 3 axis Computer Numerical Controlling (CNC) Machines using optimal and cost-effective milling cutters. The web-based tool path planning strategy is integrate with web-based CAD system to automatically generate tool paths for the CAD model using optimal cutter within desired tolerances. The tool path planning method is divided into two parts: foot print (path along which cutter moves) and cutter positioning. The tool path foot print is developed during design stage from the CAD model based on the type of surface to be machined. The foot print varies from part to part which facilitates the mass customization of wooden sign. After designing foot print, the foot print is discretized into points and the gouge-free cutter position at each of these points is found using "Dropping Method". The Dropping Method where cutter is dropped over the work piece surface, and the highest depth at which cutter can go without gouging the surface is calculated. This is repeated for all the position along the foot print. This tool path planning strategy is developed for ball nose, flat-end and radiused end milling cutter for machining wooden sign.
The tool path generated using this method is optimized for machining time, tool path generation time and final surface finish. The bucketing technique is developed to optimize tool path generation time, by isolating the triangles which has possibility of intersection at particular position. The bucketing Technique reduced the tool path computation by 75 %, and made tool path generation faster. The optimal cutter selection algorithm is developed which selects best cutter for machining the surface based on the scallop height and volume removal results. The radiused end milling cutter results in highest volume removal which results in lower machining time compared to ball nose end milling cutters, but the scallop heights is higher. However, the scallop height in the radiused end milling cutter is higher only in few regions which reduces the final surface finish. For a sign, it was found around the boundary of logo, outline of lettering, interface of border and background. Thus, in order to achieve higher surface finish and lower machining time, a separate tool path is developed using "Pencil Milling Technique" which will remove the scallops from the regions that was inaccessible by radiused end mills. This tool path with the smaller cutter will move around the boundary of logo and lettering, and clean-up all the scallops left on the surface.
The designed tool path for all the three cutters were tested on maple wood and verified against the actual Computer Aided Design model for scallop height and surface finish. The numerical testing of tool path was carried out on a Custom Simulator, ToolSim and was later confirmed by actually machining on a 3 axis CNC machine. The same sign was machined with variety of milling cutters and the best cutter was selected based on the minimum scallop and maximum volume removal. The results of the experimental verification show the method to be accurate for machining sculptured sign. The average scallop height in a machined using 1/8 th inch radiused end milling cuter and using Pencil tool path on the machined surface is found to be 0.03989 mm (1.5708 thou).
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Glancing angle deposition of sculptured thin metal films at room temperatureLiedtke, S., Grüner, Ch., Lotnyk, A., Rauschenbach, Bernd 25 April 2023 (has links)
Metallic thin films consisting of separated nanostructures are fabricated by evaporative glancing
angle deposition at room temperature. The columnar microstructure of the Ti and Cr columns is
investigated by high resolution transmission electron microscopy and selective area electron
diffraction. The morphology of the sculptured metallic films is studied by scanning electron
microscopy. It is found that tilted Ti and Cr columns grow with a single crystalline morphology,
while upright Cr columns are polycrystalline. Further, the influence of continuous substrate
rotation on the shaping of Al, Ti, Cr and Mo nanostructures is studied with view to surface
diffusion and the shadowing effect. It is observed that sculptured metallic thin films deposited
without substrate rotation grow faster compared to those grown with continuous substrate
rotation. A theoretical model is provided to describe this effect
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賓組甲骨卜旬卜辭研究 / The Research on the Text of Bu-Xun in the Bin Collection曹庭瑄 Unknown Date (has links)
本文以賓組的卜旬卜辭作為論題。先就卜辭的字體與句式兩部份做分類與整理,接著討論其驗辭的內容與所載貞人之關係,最後綜合討論以上成果。
第一章「緒論」說明研究動機與方法,以及目前學者和卜辭字體類型相關及卜旬卜辭驗辭內容相關的研究成果。第二章整理賓組卜旬卜辭的句式與字體,並嘗試透過整理成果來回應前輩學者的分期之說。第三章至第四章討論賓組卜旬卜辭的驗辭內容,並與字體整理成果對照研究。第五章主要整理於賓組中曾參與卜旬貞問的貞人,並觀察與之配合的字體類型,藉此排列出貞人間的相對時序。第六章則概述前述四章的研究成果,並說明本文透過賓組卜旬卜辭研究所得的結論。 / The purpose of this thesis is to study the content of Oracle Bone Script, constrained in Bu-Xun(卜旬),the record of the ancient psychic augury every half-decade, of Collection Bin(賓組). We carefully assorted all the pieces available by its ways of writing and its exterior forms in this range. Later, we present the connection between Zen-Ren(貞人) the ancient official psychics and Yen-Tzu(驗辭) of certain augury of Bu-Xun of Oracle Bone Scripts which note whether the prediction was found to be true or false.
In chapter one we explain the research methods used and the context of the study. In the second chapter, text of Bu-Xun in the Oracle Bone Scripts assorted by its form and font will respond to predecessors’ assortments which have been a controversy between the researchers.
In chapter three and four we further study the retained Yen-Tzu, the proven and disproven notes engraved on, of the text on Bu-Xun in Collection Bin, and then figuring out the correlation between the content of it and our assortment.
In the fifth chapter, in the study of known psychics, we further discover a new chronological order by pointing out the relations between the specific font and the names of these official psychics
The final chapter summarizes the four chapters above, and concluded the result of our research on Bu-xun Oracle Bone scripts in the large Collection Bin and explained how this study develop the field of research.
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