Spore morphology of Polypodiaceae and Grammitidaceae from Taiwan were studied with light microscope and scanning electron microscope. Totally 18 genera and 62 species were observed. Polypodiaceae spores are ellipsoidal and monolete except Loxogramme grammitoides; with spore ornamentation tuberculate, verrucate, echinate, globule, rugate, undulate, foveolate and/or vermiculate. Grammitidaceae spores are global, trilete with spore ornamentation granulate, tuberculate and/or globules. The spore surface ornamentation can be used as taxonomic characters in Polypodiaceae and Grammitidaceae at familial, genera and species levels. Based on spore characters, Polypodiaceae and Grammitidaceae can be differentiated, Loxogrammeae and Drynariaeae are not separable from the rest of Polypodiaceae, and the current classification system of Lepisorieae and Microsoreae are not .internal consistent.

In this study we have successfully developed the techniques of time-resolved electro-luminescence (EL) and optical beam induced current (OBIC) microscopy for the mapping of photonic devices. We have applied the techniques to examine various photonic devices, including light emitting diodes (LED), organic light emitting diode (OLED), and coplanar waveguide (CPW) devices. The key development in time-resolved microscopy is the technique of modulation. By measuring the phase delay between the modulation source and the output signal, the response time of the observed devices can be extracted. In electro-luminescence mapping, the phase delay is measured between the applied sinusoidal voltage and the emitted EL, while in OBIC mapping the phase delay is measured between the modulated laser beam and the resulting photocurrent. The phase delay measurements are performed with a lock-in amplifier. In this way, large enhancement in signal-to-noise ratio can also be obtained. Additionally, the technique of varying scanning rate is also developed to synchronize the data acquisition between the LSM and the lock-in amplifier, a key enabling advancement in this thesis study.

A fast method for gathering large-scale data sets through the serial sectioning of brain tissue is described. These data sets are retrieved using knife-edge scanning microscopy, a new technique developed in the Brain Networks Laboratory at Texas A&M University. This technique allows the imaging of tissue as it is cut by an ultramicrotome. In this thesis the development of a knife-edge scanner is discussed as well as the scanning techniques used to retrieve high-resolution data sets. Problems in knife-edge scanning microscopy, such as illumination, knife chatter, and focusing are discussed. Techniques are also shown to reduce these problems so that serial sections of tissue can be sampled at resolutions that are high enough to allow reconstruction of neurons at the cellular level.

<p>In the past two decades depth-sensing indentation has becomea widely used technique to measure the mechanical properties ofmaterials. This technique is particularly suitable for thecharacterisation of materials at sub-micro or nano scale thoughthere is a tendency to extend its application to the micro ormacro scale. The load-penetration depth curve of depth-sensingindentation is a characteristic of a material and can be usedfor analysing various mechanical properties in addition tohardness. This thesis deals with the mechanicalcharacterisation of bulk materials, thin films and coatings,gradient materials, and composites using depth-sensingindentation. Finite element method has been resorted to as atool to understand the indentation behaviour of materials.</p><p>The piling-up or sinking-in behaviour of materials plays animportant role in the accurate determination of materialsproperties using depth-sensing indentation. Finite elementsimulations show that the piling-up or sinking-in behaviour isdetermined by the material parameters, namely<i>E/σ</i><i>y</i>ratio and strain hardening exponent orexperimental parameter<i>h</i><i>e</i><i>/h</i><i>max</i>ratio, and the contact friction. Anempirical model has been proposed to relate the contact area ofindentation to the<i>E/σ</i><i>y</i>ratio and the<i>h</i><i>e</i><i>/h</i><i>max</i>ratio and used to predict thepiling-up orsinking-in of materials. The existence of friction is found toenhance the sinking-in tendency of materials. A generalrelationship between the hardness and the indentationrepresentative stress valid for both soft and hard materialshas been obtained. A possible method to estimate the plasticproperties of bulk materials has been suggested.</p><p>Measuring the coating-only properties requires theindentation to be done within a critical penetration depthbeyond which substrate effect comes in. The ratio of thecritical penetration depth to the coating thickness determinedby nanoindentation is independent of coating thickness andabout 0.2 for gold / nickel, 0.4 for aluminium / BK7 glass, and0.2 for diamond-like-carbon / M2 steel and alumina / nickel.Finite element simulations show that this ratio is dependent onthe combination of the coating and the substrate and moresensitive to differences in the elastic properties than in theplastic properties of the coating/substrate system. Thedeformation behaviour of coatings, such as, piling-up of thesoft coatings and cracking of the hard coatings, has also beeninvestigated using atomic force microscope.</p><p>The constraint factors, 2.24 for WC phase and 2.7 for WC-Cocemented carbides, are determined through nanoindentation andfinite element simulations. A modified hardness model of WC-Cocemented carbides has been proposed, which gives a betterestimation than the Lee and Gurland hardness model. Finiteelement method has also been used to investigate theindentation behaviour of WC-Co gradient coatings.</p><p><b>Keywords:</b>depth-sensing indentation, nanoindentation,finite element method, atomic force microscope, mechanicalproperties, hardness, deformation, dislocations, cracks,piling-up, sinking-in, indentation size effect, thin coatings,composite, gradient materials, WC-Co, diamond-like-carbon,alumina, gold, aluminium, nickel, BK7 glass, M2 steel.</p>

published_or_final_version / Anatomy / Doctoral / Doctor of Philosophy

With the gain in momentum of the structural health monitoring field in the last two decades, the popularity of ultrasonic nondestructive testing (NDT) has grown. However, ultrasonic NDT requires an expert to perform the testing and can be time consuming and costly when measured wave patterns in testing become extremely complex. A computer simulation of these tests can be utilized as a guide during actual evaluations or as a tool to train technicians. Presented in this dissertation is the development of models which simulate such acoustic phenomena as may arise in NDT. These models were developed using the distributed point source method (DPSM) for its proven capability to represent ultrasonic fields.Four sets of boundary conditions that arise from different types of commonly used acoustic transducers are modeled, enabling the visualization of the ultrasonic fields produced by the transducers. The transducer models exhibit good agreement with existing analytical solutions.In addition, the effect of a small cavity located at or near the focal point of an acoustic microscope is discussed. For this application the DPSM technique is modified so that inversion of a large global matrix is avoided, significantly improving the computational efficiency. The model shows that, as the pressure goes to zero, the velocity increases at the location of a cavity. Simulations demonstrate that the microscope is able to sense changes in position of the cavity by variations in the measured ratio of reflected to incident acoustic force.The field generated by an interferometric acoustic microscope is also presented. Qualitative agreement between the DPSM model and the experimental results of fields generated in a homogeneous fluid are obtained for a three-element lens. In the presence of a solid interface, the pressure on the edges of a converging beam near the fluid-solid interface is greater for a three-element lens than for single-element lens. A multi-element lens is also shown to exhibit oscillations in the pressure slightly above the interface.

A new experimental method to characterize the mechanical properties of metallic nanowires is introduced. An accurate and fast mechanical characterization of nanowires requires simultaneous imaging and testing of nanowires. However, there exists no practical experimental procedure in the literature that provides a quantitative mechanical analysis and imaging of the nanowire specimens during mechanical testing. In this study, a customized atomic force microscope (AFM) is placed inside a scanning electron microscope (SEM) in order to locate the position of the nanowires. The tip of the atomic force microscope cantilever is utilized to bend and break the nanowires. The nanowires are prepared by electroplating of nickel ions into the nanoscale pores of the alumina membranes. Force versus bending displacement responses of these nanowires are measured experimentally and then compared against those of the finite element analysis and peridynamic simulations to extract their mechanical properties through an inverse approach.The average elastic modulus of nickel nanowires, which are extracted using finite element analysis and peridynamic simulations, varies between 220 GPa and 225 GPa. The elastic modulus of bulk nickel published in the literature is comparable to that of nickel nanowires. This observation agrees well with the previous findings on nanowires stating that the elastic modulus of nanowires with diameters over 100nm is similar to that of bulk counterparts. The average yield stress of nickel nanowires, which are extracted using finite element analysis and peridynamic simulations, is found to be between 3.6 GPa to 4.1 GPa. The average value of yield stress of nickel nanowires with 250nm diameter is significantly higher than that of bulk nickel. Higher yield stress of nickel nanowires observed in this study can be explained by the lower defect density of nickel nanowires when compared to their bulk counterparts.Deviation in the extracted mechanical properties is investigated by analyzing the major sources of uncertainty in the experimental procedure. The effects of the nanowire orientation, the loading position and the nanowire diameter on the mechanical test results are quantified using ANSYS simulations. Among all of these three sources of uncertainty investigated, the nanowire diameter has been found to have the most significant effect on the extracted mechanical properties.

Amyloidosis is a group of diseases caused by proteins that have lost their correct three-dimensional conformation and instead assemble into insoluble fibrils in various tissues and organs. Today, more than 30 different proteins that can give rise to amyloid fibrils have been identified. Each protein that assembles into fibrils causes a specific disease. For clinical diagnosis of amyloid, antibodies are one of the most important tools. In this study, antibodies generated towards various amyloid-specific peptides were characterized and validated. This was assessed by immunohistochemistry, slot blot and SDS-PAGE and western blot. Congo red, an amyloid specific dye, was used for detection of amyloid. Immunohistochemical staining and slot blot analysis indicated that each antiserum used in this study was amyloid-specific. Antigen retrieval can facilitate staining by the techniques ability to break cross-linkages caused by fixation in formaldehyde. The results from the characterization of antisera in this study should be a great helpin clinical work on amyloid, and ensure correct diagnosis.

Laser interference fringe tomography (LIFT) is within the class of optical imaging devices designed for volumetric microscope applications. LIFT is a very simple and cost-effective three-dimensional imaging device which is able to reliably produce low-quality imagery. It measures the reflectivity as a function of depth within a sample and is capable of producing three-dimensional images from optically scattering surfaces. The first generation of this instrument is designed and prototyped for optical microscopy. With an imaging spot size of 42 μm and a 180 μm axial resolution kernel, LIFT is capable of producing one- and two- dimensional images of various samples up to 1.5 mm thickness. The prototype was built using commercial-off-the-shelf components and cost ~ $1,000. It is possible that with effort, this device can become a reliable, stable, low-quality volumetric imaging microscope to be readily available to the consumer market at a very affordable price. This document will present the optical design of LIFT along with the complete mathematical description of the instrument. The design trade-offs and choices of the instrument are discussed in detail and justified. The theoretical imaging capabilities of the instrument are tested and experimentally verified. Finally, some imaging results are presented and discussed.

Made available in DSpace on 2014-06-11T19:28:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-11-10Bitstream added on 2014-06-13T19:58:06Z : No. of bitstreams: 1 rodrigues_ks_me_bauru.pdf: 3671952 bytes, checksum: 95922ebe5feb1ccd5d65c466e158d7a8 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / Desde 1986, quando Binnig et al (1986) criaram o microscópio de força atômica (AFM), esse aparelho se tornou um dos mais importantes microscópios de varredura (SPM), sendo usado para análise de DNA, nanotubos, etc. (Rützel et al, 2006). O AFM tem como componente principal uma microviga, com uma ponteira em uma das extremidades, que vibra próximo de sua frequencia de ressonância para mandar sinais a um fotodetector que traduz esse sinal e gera as imagens da superfície da amostra. O modo de operação tapping é o mais usado, e o comportamento caótico é muito comum nesse modo de operação, por esse motivo, AFM se tornou um assunto muito importante no mundo científico. Nesse trabalho, a microviga é modelada com o uso das equações de Bernoulli, as interações entre ela e a amostra são modeladas usando o potencial de Lennard Jones. Simulações numéricas detectam movimento caótico no sistema, a necessidade de estabilizá-lo nos leva a usar os seguintes métodos: Método do Balanço Harmônico, sincronização de Sistemas Não Lineares, Método das Equações de Estado Dependentes de Riccati (SDRE), Método de Realimentação de Sinal Atrasado. Por fim, a aplicação dos métodos se mostra eficiente, com pequeno erro e fácil implementação / Since 1986, when Binnig et al (1986) created the atomic force microscope (AFM), this unit became one of the most important scanning probe microscopes (SPM) being used for DNA analysis, nano tubes, etc. (Rutzel et al, 2006). The AFM has as a main component, a micro cantilever, with a tip at its free end, which vibrates near its resonance frequency to send signals to a photo detector that translates the signal and generates images of the sample surface. The tapping mod of operation is the most widely used and chaotic behavior is very common in this mode, therefore, AFM has become a very interesting subject in the scientific world. In this work, the micro cantilever is modeled using Bernoulli's equation and the interactions between the tip and the sample are modeled using the Lennard Jones potential. Numerical simulations detect chaotic motion in the system and the need to stabilize it leads us to use the following methods, Harmonic Balance Method; Synchronization of Nonlinear Systems; the State Dependent Riccati Equation control method (SDRE); the Method of Feedback Delay. Finally, the application of the methods proved to be effective, with small error and easy implementation