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A brief survey of ferroelectrics and a statement of the purpose of the present research are given. The necessary piezoelectric equations are developed and, using Mueller's theory of Rochelle salt as a basis, a phenomenological theory for potassium dihydrogen phosphate is worked out. Measurements of the electro-mechanical constants in the Curie region are reported. The experimental results are discussed in terms of the phenomenological theory and compared with a theory proposed by W.P.Mason. Since neither offers on adequate explanation of the results, the possibility of domain wall movement is considered. Crystal growth and experimental techniques are also discussed.

Section A; Insoluble elastin was isolated from bovine aorta and ligaraentum nuchae by the use of guanidine and dithiothreitol in conjunction with collagenase, purified by affinity chromatography. The preparations were free from carbohydrate and exhibited amino acid compositions similar to that of alkali-purified elastin, with the exception of the concentration of some polar amino acid residues. N-terminal analyses indicated a very low level of polypeptide chain damage in the preparations. Upon mild alkaline treatment glycine was selectively liberated as amino-end group. Elastin from ligamentum nuchae was examined by electron microscopy, X-ray diffraction, optical polarisation analysis and dynamometry. It is suggested that elastin fibrils consist of a lateral array of primary filaments. Section B: The microfibrillar component of adult bovine ligamentum nuchae was isolated by solubilisation in guanidine-dithiothreitol followed by S-carboxymethylation and treatment with collagenase. The amino acid composition of the material was at variance to those previously reported for similar preparations. N-terminal analysis revealed glycine as the only end-group, at a concentration of 65.9 moles/106g of protein. This value, corresponding to a molecular weight of about 15,000 daltons, was in good agreement with the results of sedimentation equilibrium analyses.

Thin-walled structures are often used as kinetic energy absorbers in vehicular systems and infrastructure designs. In such applications, high specific energy absorption is usually desirable, because it is beneficial for weight reduction. The dimpling cold-roll metal forming process introduces dimpled geometry and increases the strength of sheet metal. This thesis aims to investigate the energy absorption characteristics of the dimpled thin-walled structures. A finite element (FE) modelling analysis was performed using ANSYS Explicit Dynamics solver, to predict the response of dimpled structures to dynamic and quasi-static loads. A series of experimental tests were conducted and the FE method was validated through comparing the numerical and experimental results. To understand the response of the dimpled structural components to axial crushing loads, numerical simulations were performed. A parametric study on a key cold-roll forming parameter “forming depth” was carried out to evaluate its effects on the dimpled geometry and material properties. Through the parametric study, manufacturing parameters for the cold-roll forming process were suggested to improve yield strength and energy absorption performance of dimpled steel components. It was shown that the specific energy absorption can be increased by up to 16% after optimizing the forming depth. To take the most advantage of the dimpled geometry, multi-layer dimpled thin-walled columns were analysed. The interlocking mechanism of dimpled plates were investigated and an empirical model was proposed to describe the interaction between dimpled plates. It was shown that a considerable amount of energy can be absorbed through the interaction between dimpled walls. The behaviour of dimpled columns under lateral impact loads was also investigated. It was revealed that the introduced dimpled geometry contributes to reducing the peak impact force without sacrificing the energy absorption capacity. However, this is only valid when at least one end of the dimpled thin-walled column is fully restrained.

This thesis aims to analyse a finite element method applied to an adjusted Cahn-Hilliard equation that has been used for digital image inpainting applications. We consider both the standard model with a smooth double well potential and an alternative where an obstacle potential has been used. Existence and uniqueness results are derived for both formulations by adapting techniques existing in literature for other problems. For each formulation we then propose approximations, by discretising first in space and then in time, and we derive error bounds between the weak solution of the original formulation and the solution of the discrete approximations in terms of the discretisation parameters. We then propose and implement a practical numerical scheme for both models and investigate their use in applications, alongside some other models from literature. We investigate various real digital image examples and compare the resulting inpaintings for these competing models, considering their suitability for real-world applications.

In this thesis, we present two adaptive methods for the basis enrichment of the mixed Generalized Multiscale Finite Element Method (GMsFEM) for solving the flow problem in heterogeneous media. We develop an a-posteriori error indicator which is the norm of a local residual operator. Based on this indicator, we have an offiine adaptive method to increase the number of basis functions on the coarse grid edges with large local error estimates. We also develop an online adaptive method which iteratively enriches the function space by adding new functions computed based on the residual of the previous solution. We show theoretically and numerically the convergence of the two methods. The online method is in general better than the offiine method, and both methods have faster convergence than a uniform enrichment. Analysis shows that the online method should start with certain number of initial basis functions in order to have the best performance. The numerical results confirm this and show further that with correct selection of initial basis functions, the online method can be independent of the contrast of the medium. / 在本文中，我們為混合廣義多尺度有限元法( mixed generalized multiscale finite element method) 在非均勻介質解決流動問題的應用上提出了兩種自適應的擴張基的方法。我們以公式局部餘差的範數制定了一個後驗誤差的指標。基於這個指標，我們得出一個離線的自適應方法。這個方法遂步把在指標數值較大的組網內邊鄰上定義的函數加入基。我們亦制定了一個在線的自適應方法。這個方法反復地將一些基於上一步驟所得的解去計算的函數加入基里，以擴大函數空間。我們以理論和實驗去證明兩個方法的收斂性質。一般而育，在線方法的收斂比離線方法快，而兩者的收斂速度都比均勻地擴充基所得的收斂速度快。從理論所得，在線方法需要一定數量的初始基函數才能達至最理想的收斂速度。實驗結果證實了這一點，並進一步得出，假如初始基函數的數目足夠，在線方法的收斂性質會不受介質的對比度影響。 / Chan, Ho Yuen. / Thesis M.Phil. Chinese University of Hong Kong 2015. / Includes bibliographical references (leaves 44-46). / Abstracts also in Chinese. / Title from PDF title page (viewed on 11, October, 2016). / Detailed summary in vernacular field only.

Richard Brealey, Helen Edwards. / Includes index.

During the early evening of 22 June 2007, a violent tornado impacted the western edge of Elie, Manitoba. This was Canada’s first documented F5 tornado. Three primary research questions were posed: (1) What were the pre-storm environmental conditions on 22 June 2007? (2) How did the storm and associated tornado evolve? (3) How does this event compare to other major tornadic events in Canada and the U.S.? The tornado passed in close proximity to a fixed-location Environment Canada Doppler radar at Woodlands, Manitoba. This allowed for a detailed examination of local mesoscale boundaries that were present prior to and during the event. The Elie tornado was rare in the fact that it looped three times within the main track and it moved approximately 5 km during its 40 minute lifetime causing F5 damage to homes and structures when it was an estimated 50 m wide.

During the early evening of 22 June 2007, a violent tornado impacted the western edge of Elie, Manitoba. This was Canada’s first documented F5 tornado. Three primary research questions were posed: (1) What were the pre-storm environmental conditions on 22 June 2007? (2) How did the storm and associated tornado evolve? (3) How does this event compare to other major tornadic events in Canada and the U.S.? The tornado passed in close proximity to a fixed-location Environment Canada Doppler radar at Woodlands, Manitoba. This allowed for a detailed examination of local mesoscale boundaries that were present prior to and during the event. The Elie tornado was rare in the fact that it looped three times within the main track and it moved approximately 5 km during its 40 minute lifetime causing F5 damage to homes and structures when it was an estimated 50 m wide.

In den letzte Jahrzehnten wurde viel daran geforscht zu entschlüsseln wie das Gehirn Greifbewegungen koordiniert. Das anteriore intraparietale Areal (AIP), das Hand Areal des ventralen premotorischen Kortex (F5), und das Hand Areal des primären motorischen Kortex (M1) wurden als essentielle kortikale Arealen für die Kontrolle der Hand identifiziert. Nichtsdestotrotz ist deutlich weniger darüber bekannt wie die Neuronen dieser Areale einen weiteren essentielle Parameter von Greifbewegungen kodieren: Greifkraft. Insbesondere die Rolle der tertiären, kortikalen Areale AIP und F5 in diesen Prozess ist bisher unklar. Die hier durchgeführte Studie befasst sich mit der Wissenslücke über die neuronale Kodierung von Greifkraft Planung und Steuerung in diesen Arealen. Um dies zu erreichen, haben wir zwei Makaken (Macaca mulatta) trainiert eine verzögerte Greifaufgabe auszuführen mit zwei Grifftypen (ein Griff mit der ganzen Hand oder ein Präzisionsgriff) und mit drei verschiedene Kraftniveaus (0-12 N). Während die Affen die Aufgabe ausführten, haben wir die Aktivität von “single-units“ (einzelnen Neuronen) und “multi-units“ (Gruppen von mehreren Neuronen) in den Arealen AIP, F5 und M1 aufgenommen. Wir berechneten den Prozentsatz von Grifftyp modulierten und Griffkraft modulierten “units“ (cluster-based permutation test) und berechneten wie viel Varianz in der Population von “units“ durch Grifftyp und Kraft erklärbar ist, separat für jedes Gehirn Areal mit einer modernen Dimensionalitätsreduktionsanalyse (demixed principal component analysis). 18 Wir zeigen hier zum ersten Mal die Modulation von einzelnen AIP Neuronen durch Greifkraft. Weiterhin bestätigen und erweitern wir hier vorherige Ergebnisse, welche solche neuronale Modulationen bereits in F5 und M1 gezeigt haben. Überaschenderweise war der Prozentsatz von “units“ welche durch Griffkraft moduliert werden, in AIP und F5 nicht wesentlich kleiner als in M1 und ähnlich zu dem Prozentsatz an Grifftyp modulierte Neuronen. Der Anteil an erklärte Varianz in F5 durch Greifkraft war nahezu so groß, wie der Anteil erklärt durch Grifftyp. In AIP und M1 war klar mehr Varianz durch Grifftyp erklärt als durch Kraft, aber der Anteil an erklärte Varianz beider Arealen war ausreichend, um zuverlässig Kraftbedingung zu dekodieren. Wir fanden ebenfalls eine starke neuronale Modulation für Griffkraftbedingungen vor der Bewegungsinitiierung in F5, was wahrscheinlich eine Rolle dieses Areals in der Greifkraftplanung repräsentiert. In AIP war Greifkraftplanungsaktivität nur in einen der beiden Affen vorhanden und wie erwartet nicht präsent in M1 (gemessen nur in einen Affen). Letztendlich, obwohl Greifkraftmodulation in einigen Fällen durch Grifftypmodulation beeinflusst war, war nur ein kleiner Anteil der Populationsvarianz, in den jeweiligen Arealen, durch interaktive Modulation erklärt. Information über Greifkraft können somit folglich separat vom Grifftyp extrahiert werden. Diese Ergebnisse legen eine wichtige Rolle von AIP und F5 bei der Greifkraftkontrolle, neben M1, nah. F5 ist mit hoher Wahrscheinlichkeit auch bei der Planung von Greifkraft involviert, während die Rolle von AIP und M1 geringer ist in diesem Prozess. Letztendlich, da Grifftyp- und Kraftinformation separat extrahierbar sind, zeigen diese Ergebnisse, dass Greifkraft vermutlich unabhängig von Grifftyp, im kortikalen Greifnetzwerk kodiert ist. / In de laatste decennia is er veel onderzoek gedaan om te interpreteren hoe de hersenen grijpbewegingen besturen. Het anterieure intra pariëtale gebied (AIP), het handgebied van de ventrale premotorische schors (F5) en het handgebied van de primaire motorische schors (M1) zijn geïdentificeerd als essentiële gebieden van de hersenschors die de vorm van de hand besturen. Maar er is veel minder bekend over hoe de hersenen een andere parameter van grijpbewegingen bestuurt: grijpkracht. Vooral de rol in dit proces van AIP en F5, gebieden van hogere orde, is nog nagenoeg onbekend. Deze studie richt zich op het gebrek aan kennis over de neurale codering van het plannen en besturen van grijpkracht. Om dit te bereiken, hebben we twee makaken (Macaca mulatta) getraind om een vertraagde grijptaak uit te voeren met twee grepen van de hand (een grip met de hele hand of een precisie grip) en met drie verschillende krachtniveaus (0-12 N). Terwijl de apen de taak uitvoerden, maten we de activiteit van single-units (individuele neuronen) en multiunits (collectie van enkele neuronen) in de gebieden AIP, F5 en M1. We berekenden het percentage van units die hun activiteit moduleerden op basis van grip vorm of kracht met een moderne statistieke test (cluster-based permutation test) en we berekenden de hoeveelheid variantie die werd verklaard door de grip vorm en kracht door de populatie van units van elk hersengebied met een moderne dimensie vermindering techniek (demixed principal component analysis). We laten hier voor het eerst zien dat individuele neuronen van AIP hun activiteit moduleren op basis van grijpkracht. Verder bevestigen we dat neuronen van F5 en M1 20 dergelijke modulaties vertonen en breiden we de kennis hierover uit. Verassend genoeg was het percentage units dat reageert op het besturen van grijpkracht in AIP en F5 niet veel lager dan in M1 en ongeveer gelijk aan de hoeveelheid units dat reageert op grip vorm. De hoeveelheid variantie die werd verklaard door grijpkracht in F5 was bijna net zo hoog als wat werd verklaard door grip vorm. In AIP en M1 verklaarde grip vorm duidelijk meer variantie dan grijpkracht, maar ook in deze gebieden was de hoeveelheid variantie dat grijpkracht verklaarde hoog genoeg om de kracht conditie te decoderen. We vonden ook een sterke neurale modulatie voor grijpkracht condities in F5 voordat de arm bewoog, wat mogelijk een rol voor dit gebied representeert in het plannen van grijpkracht. In AIP was activiteit voor het plannen van grijpkracht alleen in één van beide apen gevonden en zoals verwacht was het niet gevonden in M1 (onderzocht in één aap). Tenslotte vonden we dat, hoewel modulatie voor kracht werd beïnvloedt door grip vorm in sommige eenheden, slechts een kleine fractie van de variantie van de neurale populatie van elk hersengebied een gemixte selectiviteit voor grip vorm en kracht had. Informatie over grijpkracht kon daarom onafhankelijk van grip vorm worden geëxtraheerd. Deze bevindingen suggereren een belangrijke rol voor AIP en F5 in het besturen van grijpkracht, samen met M1. F5 is waarschijnlijk ook betrokken met het plannen van grijpkracht, terwijl AIP en M1 waarschijnlijk een kleinere rol hebben in dit proces. Tenslotte, omdat informatie over grip vorm en grijpkracht onafhankelijk konden worden geëxtraheerd, laten deze resultaten zien dat grijpkracht vermoedelijk onafhankelijk van hand vorm is gecodeerd in het grijpnetwerk van de hersenschors.