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Transport imaging is a SEM-based technique used to directly image the motion and recombination of charge in luminescent semiconductors, allowing for the extraction of transport parameters critical to device operation. In this thesis, transport imaging for 1D structures was initiated with work on sample preparation, modeling and initial characterization. One dimensional structures are being integrated into forefront electronics due to their inherent advantages in size, packing density and power consumption. In this work the one dimensional equation for steady state minority carrier recombination distribution solved for the Gaussian source is derived and results from numerical simulations are presented. The diameter of the SEM beam is determined experimentally allowing for accurate simulation parameters. Intensity and drift measurements on four batches of top-down wire structure samples, fabricated on a AlGaAs/GaAs/AlGaAs double heterostructure using a FIB, are presented. Significant decreases in luminescence in FIB exposed regions are reported. Spatial luminescence from single bottom-up GaN and ZnO nanowires deposited by metal initiated metal-organic CVD on Au and SiO2 substrates is imaged. CL spectra for GaN and ZnO, with peak intensities at 3.27 and 3.29 eV, are characterized. Finally, several suggestions for further research are offered including transport imaging on contacted bottom-up nanowires and a potential application of transport imaging to FIB damage characterization.

The focus of this thesis was to gather and analyze micromorphological and petrographic data on soils at the archaeological site of Dmanisi in order to better understand the extent to which the deposition and alteration of the sediments has affected the preservation of artifacts and faunal remains. A major goal of this research was to test hypothesis related to why bone material is discovered in some strata and not in others. This research focuses on the application of micromorphology (supplemented with other methods) to the soils through the use of petrographic analysis of thin sections and scanning electron microscopy. These techniques complement previous field analyses by providing a quantitative assessment of individual strata through point counting and chemical mapping. The results of this research support the hypothesis that the sediments are predominantly mafic ashes, while showing that there is very little soil development in the strata. This suggests quick episodic burial in a relatively dry climate, confirming the hypothesis for a short time sequence in the strata. Additionally, differential weathering probably did not play a significant role in the differential abundance of bone remains among the strata at Dmanisi.

A dissertation submitted to the University of the Witwatersrand in fulfilment of the requirements for the degree of Master of Science in Engineering (Metallurgy & Materials) 2016 / The surfaces of AISI 316L stainless steel plate were laser alloyed with ruthenium powder as well as a mixture of ruthenium and nickel powders using a Nd:YAG laser set at fixed operating parameters. The microstructure, elemental composition, and corrosion characteristics of the alloyed zone were analysed using optical and scanning electron microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), and corrosion potential measurements. EDS analysis of the alloyed specimen showed that through the laser surface alloying, 2 mm surface layers with 12.5wt % Ru and 5.2wt% Ru were produced on an AISI 316L stainless steel. Similar microstructures which were dendritic and columnar grains, typical of weld beads under non-equilibrium cooling conditions were observed for all samples. Hardness profile measurements showed a significant increase from 160 HV for the substrate to a maximum of 247 HV for the alloyed layer. Using an Autolab potentiostat, the corrosion behaviour and resistance of the laser alloyed layers, substrate AISI 316L, and Hastelloy© C-276 were evaluated and compared in sulphuric acid solution of different concentration and temperatures. The Hastelloy© C-276, followed by the 12.5wt% Ru presented the most noble corrosion potential (Ecorr) and the lowest corrosion current density (icorr). However, in 60wt% H2SO4 and 40oC, the 5.22 wt% Ru alloys exhibited slightly better anticorrosive properties than 12.5wt% Ru. The observed corrosion potential, Ecorr, for untreated AISI 316L stainless steel sample in 40wt% sulphuric acid solution at 40oC was -277 mV. The 5.22 wt% Ru and 12.5wt% Ru alloyed stainless steel samples presented -240 mV, and 61 mV respectively in the same solution. Besides showing comparable performance to 5.2wt%Ru sample within specific short potential ranges, Hastelloy© C-276 was generally superior in all solutions. In addition it was found that the stability of the passive layer was improved with additions of Ru. Based on the developed costing equation the cost of 5 mm AISI 316L stainless steel plate with surface area (A = 1 m2) surface alloyed with 5.2wt% Ru to a depth of 2 mm using Nd: YAG laser is estimated at R15 989, and it is less than the cost of a Hastelloy© C-276 plate of similar size which is estimated at R19 900. As the material thickness increases, the cost benefit of laser surface treatment increases and vice versa. Reduction of the Ru additions to levels below 5.2wt% would improve cost competition without detracting from performance. / MT2017

Quando se utilizam os instrumentos rotatórios, oscilatórios e os recíprocos, de NiTi (Níquel-Titânio), cortando ou raspando as paredes do conduto radicular, estes também sofrem desgastes em suas lâminas de corte. Tal ocorrência determina atritos cada vez maiores, proporcionais à perda do corte de suas lâminas, diminuindo a eficiência do instrumento, exigindo mais torques e força de penetração, aumentando ainda mais o atrito e o esforço que este sofre para desgastar a dentina, predispondo acidentes. O presente estudo avaliou o desgaste nas lâminas de corte das limas Reciproc, após 3,6 e 9 usos em canais de dentes naturais. Foram utilizados 180 dentes pré-molares inferiores e 40 instrumentos R40. Após o preparo dos canais os instrumentos foram incluídos em corpos de prova e submetidos a cortes transversais a 3 mm e 6 mm, contados a partir da ponta do instrumento. Nas imagens dessas secções transversais obtidas no MEV foi mesurada a distância entre as extremidades das lâminas de corte. O desgaste dos instrumentos foi estabelecido pela diferença entre as medidas das distâncias dos instrumentos sem uso com a média de cada instrumento, nos diferentes grupos experimentais. Observou-se diferença significante, quando comparados os grupos de 6 e 9 usos com o grupo controle. Já o grupo com 3 utilizações não apresentou diferença estatisticamente significante em relação ao grupo controle. As diferenças percentuais de desgaste a 3 mm após 3, 6 e 9 utilizações foram de 5,96%, 8,01% e 18,09%, respectivamente, em relação ao Grupo controle. As diferenças percentuais de desgaste a 6 mm, após 3, 6 e 9 utilizações foram de 2,32%, 9,54% e 21,00%, respectivamente, em relação ao Grupo controle. Conclui-se, assim, que ocorre desgaste significante das lâminas de corte dos instrumentos Reciproc, já a partir do terceiro uso reforçando a recomendação do fabricante em utilizar cada instrumento em molar e, então, descartá-lo. Palavras-chave: Microscopia eletrônica de varredura. Sistema Rotatório. / The fracture of nickel-titanium instrument, whose consequences can range from the difficulty of its removal until the absolute inaccessibility to the apical portion of the canal, remains a situation to be avoided in the safest way possible. When using the rotary instruments, and reciprocal oscillatory, NiTi, cutting or scraping the walls of the root canal, they also suffer wear in its cutting blades. Such an occurrence determines friction increasing in proportion to the loss of cutting blades, reducing the efficiency of the instrument, requiring higher torque and penetration force, further increasing friction and effort that suffers when wearing the dentin. Different rotational speeds to the long axis of the active part of the instrument are thus provoked in areas of high friction, favoring fractures, regardless of the type of movement, even if it is rotating or reciprocating. The present study sought to assess whether there is wear on cutting blades System Reciproc, since this system works through reciprocal movement within the root canal. For that, we will instrumentation in selected teeth with the kinematic system recommended by the manufacturer at zero, three, six and nine uses, corresponding to a molar tooth, two molar teeth and three molar teeth after 10 uses in each experimental group (zero , three, six and nine) according to the number of uses. The instruments are inserted into a quadrangular centralized device in the same position, and fixed in resin, which have been cut into their cross initial 3 mm and 6 mm initial these selected samples with the cross section of the system is brought to the SEM, and thus wear measured by measuring the radius of your cutting blades, and thus statistically analyzed. The results showed statistically significant differences after successive instrumentations.

by Chan Lap-kong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references (leaves 77-80). / ABSTRACT / ACKNOWLEDGEMENTS / LIST OF FIGURES / Chapter 1. --- INTRODUCTION --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Problems in Testing VLSI Circuits --- p.3 / Chapter 1.2.1 --- Test-cost-per-gate --- p.3 / Chapter 1.2.2 --- Tester Complexity --- p.3 / Chapter 1.3 --- Tester Based on Terminals Characteristics -Automatic Testing Equipment(ATE) --- p.4 / Chapter 1.4 --- Tester Based on Terminal and Internal Characteristics --- p.6 / Chapter 1.4.1 --- Mechanical Probing Method --- p.6 / Chapter 1.4.2 --- E-beam Probing Method --- p.7 / Chapter 1.5 --- Movitation for this Research --- p.7 / Chapter 1.6 --- Outline of the Remaining Chapters --- p.9 / Chapter 2. --- E-BEAM TESTER --- p.10 / Chapter 2.1 --- State-of-art of E-Beam Tester --- p.10 / Chapter 2.2 --- An Electron-optical Column of a SEM --- p.12 / Chapter 2.3 --- Beam Rastering Methods --- p.13 / Chapter 2.4 --- Voltage Contrast Phenomenon --- p.14 / Chapter 2.5 --- Configuration of an E-Beam Test System --- p.18 / Chapter 2.6 --- Advantages of an E-beam Tester --- p.20 / Chapter 3. --- BASIC PRINCIPLES --- p.21 / Chapter 3.1 --- Single-Stuck-At Fault Model --- p.21 / Chapter 3.2 --- Observability and Controllability --- p.24 / Chapter 3.3 --- Netlist Format --- p.25 / Chapter 3.4 --- Level --- p.27 / Chapter 3.5 --- Reconvergent Fanout --- p.28 / Chapter 4. --- CONVENTIONAL TEST GENERATION --- p.29 / Chapter 4.1 --- Conventional Automatic Test Generation for ATEs --- p.29 / Chapter 4.3 --- Conventional E-Beam Test Generation --- p.31 / Chapter 5. --- TEST AND PROBE POINT GENERATION --- p.32 / Chapter 5.1 --- Wafer Stage E-beam Testing --- p.32 / Chapter 5.2 --- Critical Paths Generation --- p.33 / Chapter 5.3 --- Assumptions of the Test and Probe Point Generation Algorithm --- p.35 / Chapter 5.4 --- Rules of the Test and Probe Point Generation Algorithm --- p.36 / Chapter 5.5 --- Probe Points Selection and Reduction --- p.38 / Chapter 5.6 --- Test and Probe Point Generation Algorithm --- p.40 / Chapter 5.7 --- Propagation and Justification at Fanout Site --- p.42 / Chapter 6. --- EXAMPLES --- p.45 / Chapter 6.1 --- Example of Test and Probe Point Generation for Circuit sc2 --- p.45 / Chapter 6.2 --- Example of Test and Probe Point Generation for Circuit sfc4 --- p.53 / Chapter 7. --- CONCLUSIONS --- p.61 / Chapter 7.1 --- Summary of Results --- p.61 / Chapter 7.2 --- Further Research --- p.63 / APPENDIX / Appendix A: Algorithm to Find Reconvergent Fanouts / Appendix B: Results of Test Generation for Circuit sc1 / Appendix C: Results of Test Generation for Circuit sc3 / REFERENCES --- p.77

Multicellular development in fungi is fundamentally different from that of animals or plants. In filamentous fungi, multicellular structures are formed by aggregation and adhesion of hyphae, followed by septation and specialisation of hyphal compartments within the aggregate. The perithecium, a flask-shaped sexual fruitbody produced by both Neurospora crassa and Sordaria macrospora, provides a model system in which to study fungal multicellular development. This study presents a detailed description of the morphological stages of perithecial morphogenesis in N. crassa and S. macrospora and its early stages, the ascogonial and protoperithecial stages, using a range of microscopical techniques. Details of the development of several mutants impaired in perithecial development are described, including: gene-deletion mutants of all nine mitogen-activated protein (MAP) kinases conserved in N. crassa; and three mutants pro22, pro40 and pro41 of S. macrospora, and their corresponding gene-deletions in N. crassa. The results confirm that all three MAP kinase cascades are required for sexual development. However, only the pheromone response and cell-wall integrity MAP kinase pathways, but not the osmoregulatory MAP kinase pathway, are essential for hyphal cell fusion. Evidence of cell fusion-related processes, regulated through MAP kinase signalling, have been identified as novel features important for the construction of fertilisable protoperithecia. These cell-fusion related processes include extracellular matrix deposition, hyphal attachment and envelopment. A novel phenotype of S. macrospora with defective ascogonial septation is presented. This pro22 mutant also has impaired hyphal cell fusion and produces only small, defective protoperithecia. The pro22 gene encodes a protein that is highly conserved throughout eukaryotes. Live-cell imaging revealed that this PRO22 protein is localised in the dynamic tubular and vesicular vacuolar-network of the colony periphery and in ascogonia. PRO22 is absent from the large spherical vacuoles in the vegetative hyphae of the sub-peripheral region of the colony. This points to a specific role of PRO22 in the tubular and vesicular vacuolar-network. Furthermore, the loss of intercalary septation in ascogonia suggests that PRO22 functions during the initiation of sexual development.

Thesis (Ph.D.)--University of Hong Kong, 1994. / Includes bibliographical references. Also available in print.

Thesis (Ph.D.)--University of Hong Kong, 1994. / Includes bibliographical references. Also available in print.

Fatigue crack growth in ±-Zirconium phosphate/epoxy nanocomposites was investigated. A new fatigue testing technique was implemented for miniature samples. Two different methods “strength of materials and Rayleigh-Ritz - were used in determining the bending stress. The fatigue stress and fatigue life of different nanocomposite specimens were plotted in a traditional stress-life (S-N) curve. It was inferred from the S-N plot that the values obtained from both the methods compare well. The experimental results showed that fatigue life of filled epoxy nanocomposite is more than that of the unfilled epoxy composite. A model for bending stresses, ultimate strength and the number of cycles to failure was obtained to predict a component service life without conducting elaborate tests. Scanning electron examination of the fractured surfaces revealed that the crack takes a tortuous path during its propagation course, indicating crack blunting and crack deflection roles of ZrP and CSR nanofillers, which consequently improve the fracture resistance. In case of the M-ZrP-epoxy systems, delamination of ZrP platelets from surrounding epoxy matrix was proposed as the reason behind crack growth. The improved fracture resistance of these nanocomposites was attributed to the delamination of ZrP platelets and deflection of crack direction. The superior behavior of CSR-ZrP-epoxy composites was attributed to the cavitation process and void coalescence due to CSR particles delamination.