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Master of Science / Department of Grain Science & Industry / Yong-Cheng Shi / The objective of this study was to systematically understand the changes of rice during the parboiling process. Isolated rice starch, milled rice and paddy rice kernels of the same variety (18% amylose) were examined after steeping at temperatures (60-75 oC) below and above the onset of rice starch gelatinization temperature for different durations in 66.7% water. Changes in gelatinization temperatures were greater for isolated starch ˃> milled rice ˃ paddy rice. Annealing above samples’ original To caused partial gelatinization, loss of crystallinity, and birefringence as determined by X-ray diffraction (XRD), differential scanning calorimetry (DSC), and light microscopy. However, starch granules in milled rice and paddy rice, which were surrounded by non-starch components, maintained their granule integrity. Scanning electron microscopy (SEM) revealed morphological differences between starch granules within native and steeped rice kernels. Steeped kernels had denser structures than native kernels, as determined by high resolution X-ray microtomography. Rice starch granules and kernel characteristics were altered significantly during steeping and changes in isolated starch differed from those inside the rice kernels. To study the changes during the steaming process, the morphology of the rice kernel and starch granules within the kernel were examined immediately after heating at110oC for 20 min. Starch was completely gelatinized as determined by DSC and XRD, indicating the disruption of all short-range crystallinity of starch in parboiled rice. However, SEM showed intact starch granules and light microscopic images showed starch granules embedded in the rice kernel. Interestingly, these granules displayed Maltese cross patterns. For the first time, we demonstrated that starch granules were birefringent and showed the Maltese cross but were not crystalline.

by Ma Tak-lun. / Bibliography: leaves 68-69 / Thesis (M.Phil.) -- Chinese University of Hong Kong, 1983

Siu, King Sang = 網狀合金的白鑄鐵的退火處理 / 蕭健生. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references. / Abstracts in English and Chinese. / Siu, King Sang = Wang zhuang he jin de bai zhu tie de tui huo chu li / Xiao, Jiansheng. / Abstract --- p.i / 摘要 --- p.iv / Acknowledgments --- p.v / Table of contents --- p.vi / List of table captions --- p.viii / List of figure captions --- p.ix / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Composite Materials --- p.1 / Chapter 1.2 --- Nanostructured Material --- p.2 / Chapter 1.3 --- Typical Methods of Fabrication of Nanostructure Material --- p.3 / Chapter 1.4 --- Combination of the Ideas of Nanostructure and Composite --- p.4 / Chapter 1.5 --- Phase Separation --- p.5 / Chapter 1.6 --- Nucleation and Growth --- p.6 / Chapter 1.7 --- Spinodal Decomposition --- p.8 / Chapter 1.7.1 --- The Initiation of Spinodal Decomposition --- p.8 / Chapter 1.7.2 --- Dynamics of Spinodal Decomposition --- p.9 / Chapter 1.7.2.1 --- Classical Equation of Diffusion --- p.9 / Chapter 1.7.2.2 --- Factors Deterring Spinodal Decomposition and Formation of Spinodal Network --- p.10 / Chapter 1.7.3 --- Relationship between Wavelength of Spinodal Network and Undercooling --- p.11 / Chapter 1.7.4 --- "Comparing Nucleation and Growth, and Spinodal Decomposition" --- p.11 / Chapter 1.8 --- How to achieve large undercooling --- p.12 / Chapter 1.9 --- Thermal annealing --- p.12 / Chapter 1.9.1 --- Recovery --- p.13 / Chapter 1.9.2 --- Recrystallization --- p.13 / Chapter 1.9.3 --- Grain Growth --- p.14 / Chapter 1.9.4 --- Equation of Ideal Grain Growth --- p.14 / Chapter 1.9.5 --- Factor that slow down grain growth --- p.15 / Chapter 1.10 --- Prospect of this Thesis Project --- p.16 / References --- p.17 / Figures --- p.19 / Chapter Chapter 2 --- Experimental Method / Chapter 2.1 --- Introduction --- p.26 / Chapter 2.2 --- Sample Fabrication --- p.26 / Chapter 2.3 --- Procedures for Preparing Thermal Annealing --- p.26 / Chapter 2.3.1 --- Preparation of Vacuum Environment --- p.26 / Chapter 2.3.2 --- Sealing Silica Tube --- p.27 / Chapter 2.4 --- Furnance --- p.27 / Chapter 2.5 --- Samples Analysis --- p.27 / Chapter 2.5.1 --- Optical Microscope --- p.27 / Chapter 2.5.2 --- Scanning Electron Microscope (SEM) Analysis --- p.27 / Chapter 2.5.3 --- Transmission Electron Microscope (TEM) Analysis --- p.28 / Chapter 2.5.3.1 --- Sample Preparation --- p.28 / Chapter 2.5.3.1.1 --- "Grinding, Polishing and Pouching" --- p.28 / Chapter 2.5.3.1.2 --- Dimpling --- p.29 / Chapter 2.5.3.1.3 --- I on Milling --- p.29 / Chapter 2.5.3.2 --- Phase Identification --- p.30 / References --- p.31 / Figures --- p.31 / Chapter Chapter 3 --- Grain Growth in Fe81C17Si5 / Chapter 3.1 --- Abstract --- p.34 / Chapter 3.2 --- Introduction --- p.35 / Chapter 3.3 --- Experimental --- p.36 / Chapter 3.4 --- Result --- p.37 / Chapter 3.5 --- Discussion --- p.44 / References --- p.48 / Figures --- p.49 / Chapter Chapter 4 --- High temperature thermal annealing of Fe81C14Si5 network alloys / Chapter 4.1 --- Abstract --- p.74 / Chapter 4.2 --- Introduction --- p.75 / Chapter 4.3 --- Experimental --- p.76 / Chapter 4.4 --- Result --- p.77 / Chapter 4.5 --- Discussion --- p.83 / References --- p.86 / Figures --- p.87

Multilayered aluminium alloy composites were produced by accumulative roll bonding (ARB) to very high strain to generate sheet materials consisting of either 32 or 64 alternating layers of Al and Al-0.3w.%Sc alloy. Based on the starting heat treatment condition of the Al(Sc) alloy and the roll bonding temperature, several different Al/Al(Sc) combinations were produced: (i) SSSS-ARB (Al(Sc) in the supersaturated condition; Tdef = 200 ???C; 32 layers); (ii) Aged-ARB (Al(Sc) in the artificially aged condition; Tdef = 200 ???C; 32 layers), and (iii) SSSS-ARB-HT (Al(Sc) in the SSSS condition; Tdef = 350 ???C; 64 layers). Regardless of the roll bonding conditions, Al(Sc) in the form of a dispersion of ultrafine Al3Sc particles strongly impedes structural changes during thermomechanical processing whereas Al readily undergoes extensive dynamic and static restoration. The major aim of the thesis is to understand the effect of initial microstructure and processing conditions on microstructural development in these multilayered Al/Al(Sc) composites. The microstructures were investigated mainly by backscatter electron (BSE) and ion channeling contrast (ICC) imaging in the DualBeam Platform and transmission electron microscopy (TEM) whereas the crystallographic nature of the microstructures were investigated by electron backscatter diffraction (EBSD) and the various diffraction techniques available in the TEM. The mechanical properties of the materials were investigated by hardness and tensile testing. The deformation microstructure and texture of these two alloy combinations were strongly influenced by both the initial heat treatment condition of the Al(Sc) alloy whereby large-scale shear bands are generated during rolling when a dispersion of fine Al3Sc particles is present in the Al(Sc) layers. The deformation mechanism of both SSSS-ARB and Aged-ARB was strongly controlled by the relative hardening behaviour of adjacent layers. In Aged-ARB, a higher magnitude of in-plane shear stress, exceeding the flow stress of Al(Sc), was operative at the interfaces between layers; this was shown to cause the shear banding in this material. All materials were annealed for up to 6h at 350 ??C. This extended annealing generated alternating layers of coarse grains (Al layers) and a recovered substructure (Al(Sc) layers) with the substantial waviness of the layers in both Aged-ARB and SSSS-ARB-HT being inherited from the as-deformed material. While the Al(Sc) layers remain unrecrystallized in all materials due to particle pinning effects, the Al layers underwent continuous and discontinuous recrystallization after low and high temperature roll bonding, respectively. Shear banding in Aged-ARB also resulted in a reduction in intensity of the rolling texture components and had a randomizing effect on the recrystallization texture of the Al layers. The Al/A(Sc) multilayered composites were found to conform to the classic inverse strength/ductility relationship and no significant improvement in ductility (for a given strength) was evident. The barriers to achieving an excellent combination of ductility and strength (i.e. toughness) in these materials were identified to be delamination of the layers, which can be largely reduced (or eliminated) by careful control of starting materials (heat treatment condition and thickness) as well as the processing parameters during ARB.

Wurtzite GaN epilayers grown by metal organic chemical vapor deposition on sapphire substrates were subsequently ion implanted with Er to a dose of 5×10¹⁵ cm⁻². The implanted samples were annealed in nitrogen atmosphere at different temperatures to facilitate recovery from implantation related damage. In this paper we report the annealing behavior of Erbium implanted GaN by using micro Raman spectroscopy and optimized annealing condition. We have observed almost full damage recovery of the crystalline quality of Er implanted GaN after annealing at 1000°C for 2 minute. This observation is further confirmed by using AFM images. / Singapore-MIT Alliance (SMA)

Thesis (M.Sc.)--Memorial University of Newfoundland, 2005. / Restricted until October 2007. Bibliography: leaves 133-164.

The data used for the construction of genome maps is imperfect, therefore the mapping of a physically linear structure must take place in a very uneven feature space. As the number of genes to be ordered grows, it appears to be impractical to use exhaustive search techniques to find the optimal mapping. In this paper we compare genetic algorithms and simulated annealing, two methods that are widely believed to be well-suited to non-smooth feature spaces, and find that the genetic algorithm approach yields superior results. Here we present performance profiles of comparable implementations of both genetic algorithms and simulated annealing. We have translated the problem to a form comparable to the shortest-path problem and found that the ability of a genetic algorithm to combine different partial solutions seems to be responsible for its superiority over the simulated annealing method. This is because in the genome mapping problem, as in the Traveling Salesman Problem, good solutions tend to be rather sparse and because optimal subtours tend to be components of nearly optimal tours. / Graduation date: 1994

Shape memory alloys (SMAs) are a class of alloys that display the unique ability to undergo nonlinear deformations and return to their original shape when heat is applied or the stress causing the deformation is removed. This unique shape memory characteristic is a result of a martensitic phase-change, which can be temperature induced (shape memory effect) or stress induced (superelastic effect). In this study, the cyclical behavior of NiTi, a binary shape memory alloy, is compared to the cyclical behavior of NiTiCr, a ternary SMA. The purpose of this study is to compare the behavior of a 0.085-in. diameter NiTiCr wire with the behavior of the same size NiTi wire to determine whether ternary SMAs are more viable ways to take advantage of the unique properties of SMAs for seismic applications. The experimental results showing the superelastic behavior of these alloys under cyclical tensile loading are summarized with attention to the effects of annealing temperature, strain rate, and cyclical training on the stress-strain hysteresis, maximum recoverable strain and equivalent viscous damping.

Fully conjugated coil-like polymer poly-(3-hexylthiophene) (P3HT) and aromatic heterocyclic copolymer poly[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta-[2,1-b;3,4-b¡¬]- dithiophene)-alt-4,7-(2,1,3-benzothiadiazole] (PCPDTBT) were applied separately as donors mixed with derivatized carbon fullerence [6,6]-phenyl C61-butyric acid methyl ester (PC61BM) serving as an acceptor. Single layer photovoltaic cells of ITO/ PEDOT:PSS/polymer:PC61BM/LiF/Al were fabricated to study photovoltaic effect of layer thickness, thermal annealing, composition variance, and processing solvent. At a P3HT:PC61BM weight ratio of 1:1, the thermally annealed photovoltaic cells achieved a conversion efficiency (£bp) of 4.58 % from enhanced contact between cathode and active layer. At a PCPDTBT:PC61BM weight ratio of 1:1.25, the best £bp was 2.62 %. The efficiency difference was due to PCPDTBT:PC61BM was highly phase separated preventing the formation of conductive interpenetrating network to facilitate charge transport. Its device fill factor was limited to be 38 %. Under the same spin coating speed, solutions of different PC61BM concentration would yield different spun film thickness leading to large change in conversion efficiency (£bp). At a constant active layer thickness, £bp tended to be stable indicating that £bp was affected more by the layer thickness than by PC61BM concentration. A layer of mixing P3HT: PCPDTBT: PC61BM would expand the absorption range from visible to near infrared. However, an increased PCPDTBT concentration did not help £bp. This is due to charge transport imbalance between P3HT and PCPDTBT leading to an £bp less than those of individual blends with PC61BM. Device £bp was consistently higher for using a solvent with a boiling point higher than polymer glass transition temperature (Tg).