http://dspace.cityu.edu.hk:80/handle/2031/20 2013-04-30T07:45:22Z http://dspace.cityu.edu.hk:80/handle/2031/6656 Title: Analysis of Feng Zikai's Chinese cartoons and their computer reproduction Authors: Zhang, Jing ( 張晶) Abstract: Feng Zikai, is an outstanding modern Chinese cartoonist, as well as an accomplished essayist, scholar, educator, translator, calligrapher, and musician. He is chiefly known for developing a unique style of Chinese cartoons incorporating a combination of traditional Chinese fine arts features and references to Western painting styles. The trajectory of Feng's career reflects a characteristic of modern Chinese intellectuals, that of, placing value on developing deep knowledge in multiple disciplines simultaneously. Mostly due to the difficulties with gaining access to primary resources, publications to date, especially journal articles, draw on a narrow range of works and somewhat haphazardly extend the discussion of Feng's creations and ideas. Based on a more extensive access to Feng's Chinese cartoons and essays, as well as Sino-Western publications about his life and work, this research provides a graphics-oriented analysis of Feng's art works, focusing on the foundations, grammatical theories, and themes of his Chinese cartoons. Moreover, programs and techniques for simulating the styles of Chinese brush work in contemporary computer graphics and animation are quite successful in a generic sense, but they are not very successful in reproducing a specific artist's painting style in an interactive digital painting process. This research therefore also aims at developing a preliminary computer framework capable of reproducing the specific artistic styles of selected Chinese paintings, focusing on a case study of a subset of the works of Feng Zikai, with specific reference to his signature painting of human facial features. Aside from the potential technical benefits of such a study, a comprehensive understanding of Feng's graphic style will also be relevant to discussions of the relationship between tradition and novelty in the world of Asian art and aesthetics. Notes: CityU Call Number: NC1699.F4 Z45 2011; xi, 431 leaves : ill. (some col.), facsims. 30 cm.; Thesis (Ph.D.)--City University of Hong Kong, 2011.; Includes bibliographical references (leaves 384-397) 2011-01-01T00:00:00Z http://dspace.cityu.edu.hk:80/handle/2031/6655 Title: New strategies for designing live computer music Authors: Leung, Kei Cheuk Kechard ( 梁基爵) Abstract: This thesis explores the methodology for designing computer-based digital musical instruments (DMIs) to create a new direction for live computer music performance. Three forerunners of DMIs, Extended Tablet, Reactable and Silent Drum, are reviewed to give background information of DMIs, of which the individual components, performance contexts and artistic factors are investigated. The present study presents four case studies, each discussing a new DMI or installation, namely the Pod Drum, Control Table, 3D Fabric, and 'Transparent Caprice'. They were inspired by different motivations, artistic considerations, and technology involvement. Performances of original compositions for each of the creations are also presented. This thesis highlights three key implementations for the design of DMIs: (1) exploring gestural control in live computer music; (2) enhancing transparency of the control process and sound production of DMI designs; and (3) increasing the importance of repertoire and actual performances in the development of DMIs. Notes: CityU Call Number: ML1380 .L48 2011; 107 leaves : ill. (some col.) 30 cm.; Thesis (M.Phil.)--City University of Hong Kong, 2011.; Includes bibliographical references (leaves 105-107) 2011-01-01T00:00:00Z http://dspace.cityu.edu.hk:80/handle/2031/6654 Title: Boundary slippage effect on hydrodynamic lubrication Authors: Yip, Lee Kei ( 葉莉姬) Abstract: It is well aware that efficiency of machines and engines can be increased by lubrication. Contact parts or components in relative motion in a well-lubricated machine can be totally separated by a hydrodynamic lubricating film which prevents direct solid contact and reduces friction. However, viscous friction still exists and its magnitude is proportional to the viscosity of the lubricant. Simply speaking, using thinner lubricating oil can reduce the magnitude of viscous friction, but it also reduces the thickness of the lubricating film, i.e. lubricating effect is affected. Thus, the means of using thinner oil to reduce lubricating friction is only limited and not practical. Recently, an idea for reducing lubricating friction on the basis of boundary slippage has been proposed. If the lubricant can slide on or move with a different speed of the solid surface, friction can thus be reduced. To better use the boundary slip phenomenon, this work aims to find out its effects on hydrodynamic lubrication for various operation conditions through experimental and theoretical studies. The experimental study started with a typical hydrodynamic system - squeeze film. The set up included two horizontal parallel planes that were submerged in a specimen lubricant. The lubricant was squeezed in the vertical direction. The load and the corresponding relative displacement between two parallel planes were captured. Experiments were carried out with various pairs of parallel planes. The lower plane was fixed (untreated) while the upper plane was modified with different surface treatments for various interfacial adhesion between the solid and the liquid. By comparing the experimental measurements with the hydrodynamic lubrication theory derived based on no-slip boundary conditions, genuine differences were obtained which proved the existence of boundary slippery. Based on the experimental and theoretical comparison, the degree of slip was inferred. To more accurately and systemically capture the parametric effects on boundary slip, shear film experiments were carried out with an optical slider test rig. The hydrodynamic lubricating film was generated with a rotating transparent disc and a stationary slider of adjustable tilted angles. The affinity of the specimen oil to the bounding surfaces, as quantified with contact angle, was systematically varied by the amount surfactant added to the same base oil such that a wide range of contact angles, from 3 to 52 degrees, was generated. The variation of film thickness against rotational speeds and different loads were detected by optical interferometry, which provides submicron measuring accuracy. Comparing the experimental results of load and film thickness to the hydrodynamic lubrication model with the critical shear stress criterion of slippage, the degree of slip can be illustrated and the critical shear stress can be inferred. In squeeze film experiments, the load carrying capacity was decreased with increasing the contact angle. The critical shear stress, which was inferred from the comparison of the experimental and theoretical results, was found having a negative effect on the carrying load. Moreover, it was found the load carrying capacity varied linearly with the squeeze velocity and this linear relationship was generally applied to specimen oils of different interfacial affinity. In the slider test, the contact angle was found increased with the amount of surfactant added. The experimental results illustrated that the film thickness was decreased with increasing the contact angle for a given load and speed. On the other hand, the increased contact angle would promote a reduction in the critical shear stress as well as the work of adhesion. Hence, lowering the wettability of an oil-solid system (larger contact angle) would promote slip, which, in turn, reduces the film formation capacity. Moreover, it was found that the critical shear stress is a linear function of shear rate. Lastly, the identified significant parameters that affect boundary slippage include the contact angle (or wettability), the critical shear stress, the shear rate, the speed and the work of adhesion. Notes: CityU Call Number: TJ1073.5 .Y56 2011; xiv, 124, [18] leaves : ill. 30 cm.; Thesis (M.Phil.)--City University of Hong Kong, 2011.; Includes bibliographical references (leaves 119-124) 2011-01-01T00:00:00Z http://dspace.cityu.edu.hk:80/handle/2031/6653 Title: A study on the mechanical properties and performance of selected thermoplastic and thermosetting composites for engineering applications Authors: Yeung, Kai Kin ( 楊啟健) Abstract: Fibre reinforced composites, a combination of reinforcing fibre and matrix, offer many advantages over traditional materials and therefore found wide application in the aerospace and construction industry. Among the advantages that traditional thermosetting composites offer, the most citied are weight saving, high modulus, high strength-to weight ratio, corrosion and fatigue resistance. Recently, the development of high performance thermoplastics composites has been accountable for increasing their demand. Whereas the developed thermosetting composites have created environmental concerns because of hazardous fumes generated during fabrication of composites and, most importantly, they are non-recyclable. Lack of previous experience on the durability of thermoplastic composites and the demand for more understanding of their properties in the planning and design stage is increasing. Such advances have created in inescapable need for establishing an understanding and comparison of the mechanical behaviour of thermoplastic and thermosetting composites. The main aim of this research is to investigate and explore the potential advantages and feasibility of thermoplastic composites in typical applications that are traditionally deploying thermosetting composites. In addition, the study also widens the scope of designing composites in a simple and direct way by industry persons, without the need for complex mathematical analysis. This study also covers issues of environmental aging, durability and cost analysis for thermoplastic and thermosetting composites that can serve as a ready reference for the industry. The objectives of this research are: 1) to develop a class of thermoplastic-based Boron, Kelvar-49 and Carbon reinforced fibre composite laminates; 2) to study the mechanical behaviour of the developed composites and explore the application of theoretical models for predicting the mechanical behaviour of these composites, and 3) to study the value, benefit and potential application of thermoplastic composites for the industry. The selection of fibres for this study was based on an initial study using some simple theoretical models for predicting the mechanical properties of a large number of fibres with combination of several thermoplastic and thermosetting matrixes. The fibre and matrix combinations are chosen such that low, medium and high strength composites are developed for further study. The three types of fibres selected (Boron, Kevlar-49 and Carbon) are combined with three types of thermoplastics (Styrene Acrylonitrile (SAN), Acrylonitrile Butadiene Styrene (ABS) and Polyethylene (PE)) and two types of thermosetting matrices (Polyimide (PI) and Low Modulus Polyester). Firstly, the prediction of mechanical behaviour of composites with these chosen combinations of constituents has been made. Theoretical prediction of mechanical properties of thermoplastic and thermosetting composites from their constituent's properties has been made by using the following micromechanical models: (1) Rule of Mixtures (ROM), Halpin-Tsai, Eshelby's Inclusion model, Modified Rule of Mixtures (Modified ROM) and Self-Consistent model for uniaxial longitudinal tensile strength; (2) Rosen - extensional mode, Rosen - shear mode and Xu-Reifsnider Model for longitudinal compressive strength and; (3) Inverse Rule of Mixture (IROM) and Modified Inverse Rule of Mixtures (Modified IROM) for transverse strength. All the tested specimens were prepared in sheet form by modified pultrusion process which is being widely used in the manufacture of thermosetting composites. The fibre volume fraction was maintained at 61% which is commonly used for most structural composites. The experimental work to evaluate the mechanical properties of the developed composites included uniaxial tension test following British Standards BS 2782 Part 3 Method 321:1994, compression test based on BS 2782 Part 3 Method 345A:1993 standard, and three-point bending test following BS 2782 Part 3 Method 335A:1993 standard. The consolidated results indicate that all experimentally obtained strength values are the highest for Boron composites when compared with Carbon and Kevlar-49 thermoplastic and thermosetting composites. The tensile strengths are nearly the same for all composites prepared with the same fibre but with different matrix materials, indicating that they are fibre dominated. Their respective compressive strengths are lower than tensile strengths as they appear to be matrix dependent. The flexural strengths are between the tensile and compressive values, whereas the flexural modulus values are the lowest among the three types of loading, except Boron-Polyimide composite having its flexural strength higher than tensile strength. In assessing the standing of theoretical models which predict the mechanical properties of Boron, Carbon and Kevlar-49 thermoplastic and thermosetting composites in terms of their constituents, it is often difficult to discriminate between the validity of assumptions made in the models and constructional imperfections within the specimens. Results indicate the theoretically estimated tensile strengths using ROM model are dramatically higher by an order of magnitude than the experimentally obtained tensile strengths. The tensile strengths are controlled and dominated by fibre alone and the matrix contribution to their strengths is negligible. From the compression tests, it is found that micro-buckling approach has made little success in predicting the compressive strength by Rosen's model whereas Xu-Reifsnider model has shown good agreement with the experimental values which are only about 10% lower than theoretically obtained compressive strengths. The matrix properties seem to be the major contributors of the prepared composites. It is found that the flexural strength values obtained from the three-point flexural tests are about 14-17% lower than the corresponding theoretical values using IROM models. These properties have more complex dependency with respect to the properties of participating fibre, matrix and manufacturing. Systematic and numerical costing analysis of respective thermoplastic and thermosetting composites has been made for managing their application. The total product cost is established based on factors such as material, labour, overhead, selling expenses, general administrative expenses, taxes as well as net profit. The results indicate that the production cost is highest for Boron based thermoplastic composites among all the selected composites whereas thermosetting composites with Carbon are the lowest. From the comparison of cost per unit strength analysis, it is found that Boron-Polyethylene, Carbon-Polyimide and Boron-SAN gave the best results in tensile properties, flexural properties and compressive properties, respectively. The outcomes can assist the fabricator to choose suitable composites in order to suit their specific loading requirement during design stage. In conclusion, the micromechanical models can hardly be used for exact practical analysis of composite materials and structures because even the most vigorous models cannot describe adequately the real composites evolved during manufacturing. Many features such as voids, microcracks, and randomly damaged and misaligned fibres cannot be formally reflected in mathematical models. In such circumstances, micromechanical models may be used for initial qualitative analysis, providing an understanding of how the constituent parameters affect the mechanical properties followed by experimental determination of these properties. Unintentional variations in fibre alignments provide unforeseeable complications and variations to the experimental results and the problems are enhanced in fabric reinforced blocks. Even with these reservations and complications, the results obtained in the present investigation fall into a clearly identified pattern and the results obtained are readily applicable in the composites industry. Notes: CityU Call Number: TA418.9.C6 Y48 2011; xvii, 202 leaves : ill. 30 cm.; Thesis (Eng.D.)--City University of Hong Kong, 2011.; Includes bibliographical references (leaves 153-161) 2011-01-01T00:00:00Z