The research detailed in this thesis investigates the practical application of Computational Fluid Dynamics (CFD) to downwind sail design. Simulations were performed using CFX-5, an unstructured commercial CFD package. The research focuses on the performance of the SST and k-ω turbulence models which were judged to be CFX-5's most appropriate turbulence models for downwind sail flows. Two-equation turbulence models are viewed as the most appropriate model type for sail simulations, they capture a significant amount of the flow physics whilst providing turnaround times for sail simulations of less than one day. CFD simulations were compared with experimental data for a flat plate at shallow angles of incidence. This test case holds particular relevance to sail flows since both flows are affected by leading edge separation bubbles which form due to knife-edge separation at sharp leading edges. The CFD captures this leading edge bubble well, with the SST model predicting the length of the bubble with 7% of the experimental value. Wind tunnel data was gathered for two-dimensional downwind sail sections for the purpose of CFD validation. A preliminary wind tunnel study was carried out using a low aspect ratio model. The tests were prone to three-dimensional effects and only three-dimensional CFD simulations were capable of successfully reproducing the flow. High aspect ratio wind tunnel test results were also conducted in an effort to obtain nominally two-dimensional wind tunnel data. Surface pressures were measured using Pressure Sensitive Paint (PSP), however due to the low dynamic pressure of the tests error appeared in the data and comparison with the CFD was poor Results show that CFD is capable of qualitatively reproducing downwind sail flows, the leading and trailing edge separation regions were captured and the CFD results compared well with wind tunnel flow visualization. Finally, CFD simulations were used to investigate the two-dimensional downwind sail design space through a parametric study of sail draft and camber. Results show that increasing camber increases both lift and drag a trend that also is evident in three-dimensional sail designs. It is also shown that gains can be made by using designs with draft values as far aft as 60% which helps reduce the extent of trailing edge separation. This parametric design study illustrates how CFD can be used successfully to analyse design trends and rank designs. The research presented illustrates how CFD can be used in the design process but also that care must be made in validating the method. Through this study the relative strengths and weaknesses of the turbulence models are better understood. Whilst CFD cannot yet be reliably used for downwind sail performance prediction, it is still a useful tool for investigating the flow structure which leads to better understanding of the design space.

An investigation of cyclic variability in a single-cylinder spark ignition engine fuelled by natural gas was carried out. The effects of combustion chamber shape and compression ratio were examined intensively. Four different combustion chambers were tested and compression ratio was varied in the range of 8.5:1 to 15:1. For each test condition, the in-cylinder pressure data were recorded at each degree of crank angle rotation for a total of two hundred consecutive engine cycles. These pressure-time histories were used for the detailed study of combustion characteristics. The generalized plot of maximum pressure and location at which maximum pressure occurs was demonstrated as an effective means of diagnosing the cyclic variability. It was shown that compression ratio had negligible effect on cyclic variability, but combustion chamber shape had a strong influence. The indicated mean effective pressure proved to be a good index for measuring cyclic variability for a wide range of operating conditions. However, for specific cases in which the variation of indicated mean effective pressure shows poor sensitivity, maximum pressure and maximum rate of pressure rise are useful measures. For high compression ratio engines, a compact combustion chamber arranged around the spark plug has been shown to be superior for reducing cyclic variability. In addition, a study of a model for the small-scale structure of turbulence using the data from these experiments showed good agreement with those from the literature. Alternative assumptions for estimating turbulence length scale were tested and a preferred method is recommended. The study showed that the fast burning combustion chamber is the solution to reduce cyclic variation. However, cyclic variations of maximum pressure and its location in the fast burning condition still exist and continued research to reduce these cyclic variations should concentrate on the variation of characteristics of flame kernel creation and growth from cycle to cycle.

An original solution method ("Snippy") is developed for the rectangular stock cutting problem, and compared with the commercially available package "OREC" by applying both methods to industrial order books. Arguments are presented to show that the solutions found by Snippy are optimal for all except one of the order books. Snippy incorporates two innovations. The first is a new method for generating guillotinable cutting patterns, the Trickle Method. This is an incremental dynamic programming technique which is especially suited for interaction with the Simplex Method via column generation. The second development involves a class of non-guillotinable patterns that can be constructed using essentially guillotine techniques. In particular, a relatively minor modification to the Trickle Method allows the generation of good non-guillotinable patterns.

Whole document restricted, see Access Instructions file below for details of how to access the print copy. / An analysis of the industrial productivity of New Zealand heavy engineering companies is presented, and methods for improving the overall productivity of the heavy engineering industry and similar industries with job-shop type production are developed. The industry's productivity problems had been obvious for years. However, due to the lack of data and inadequacy of existing productivity improvement approaches, it had never been possible to quantify the extent of these problems, to analyse their causes and to develop methodologies for long-term improvement. The present investigation consists of two major aspects. The scientific element is concerned with the development of a methodology for productivity improvement appropriate to the situation of heavy engineering in New Zealand. This is supported by practice-oriented work in the industry, consisting of data acquisition activities in general, and of pilot studies in selected companies in order to assemble, analyse and evaluate specific data on productivity problems, and to apply and test the results thereof. The development of a methodology for productivity improvement is based on an extensive survey of literature on productivity measurement and improvement methods. The results of this survey, which was performed in parallel with the collection of industrial data, indicate that existing methods are not adequate to satisfy the requirements of productivity improvement in the local heavy engineering industry. On this basis, in-depth pilot studies in ten heavy engineering companies were performed. The objectives and methodology of these pilot studies are described in detail, as their results have a sizeable impact on the overall methodology chosen for this research. One of the most important conclusions drawn from the pilot studies is that productivity problems in the New Zealand heavy engineering industry cannot be solved by concentrating solely on workshop fabrication and technological factors. Generally these problems have complex cause-and-effect structures, and a multitude of non-technological factors from outside the workshop are involved. In order to account for these interrelated factors, a systems engineering approach was used, which offers a suitable basis for a productivity improvement methodology applicable to the situation as identified in the pilot studies. A main step in the system engineering approach is the development of a systems model which is used for structuring the complex inter-relationships found in practice. On the basis of this systems model of heavy engineering productivity a Productivity Assurance Programme is developed. This programme combines elements of quality assurance methods and the 'productivity cycle' principle of continuing improvement. The main elements of the Productivity Assurance Programme are matrices developed for the evaluation of the requirements of productive heavy engineering operation, and for the analysis of the productivity levels of the company where they are applied. The combination of these aspects provides a decision base on which organisational improvements can be founded. Due to its modular structure and the flexibility in defining specific productivity requirements, the applicability of the Productivity Assurance Programme is not limited to New Zealand heavy engineering companies, but also covers other job shop type industries with similar productivity problems. I case study illustrates the application of the Productivity Assurance Programme in practice.

This work presents a 50-industry input-output model of Northland's economy and demonstrates how input-output analysis could be used to enhance regional planning in New Zealand. As it is the first regional input-output model in this country to incorporate significant survey and secondary data the survey procedure and model construction are outlined. The input-output table is used to discuss important regional transactions and the purchase and sales patterns of industries. The model analyses industries' contributions to export receipts and import payments and calculates the impact of changes in export receipts on regional income and imports. A comprehensive multiplier analysis of Northland's economy covers output, income, employment and imports and confidence limits for the multipliers are developed using the Monte Carlo technique to simulate survey errors. The model explores the economic implications of forestry expansion in Northland and discusses the areas available for afforestation, planting rates, tree management, wood supply and wood processing options in the region. The modifications made to the model and data requirements for simulating forestry expansion are outlined and employment and income impacts given for three types of processing complexes and for forestry expansion as a whole. Finally an economic evaluation is made of the impacts of processing-plant construction and supporting services.

A mechatronic chewing robot of 6-DOF mechanism which consists mainly of the skull, six crank actuators, end effector and motion control system has been designed and is required to simulate human chewing behaviours while the chewed food properties are evaluated. The robotic mechanism is proposed and its kinematic parameters are defined according to the biomechanical findings and measurements of the human masticatory system. This thesis is concerned with the design and implementation of trajectory tracking control for robotic jaw actuators via Galil motion controller. The aim of this project is to simulate the dynamics behaviour and force-motion control of the robot, and to quantitatively assess food texture changes during chewing. A control system based Galil motion control card has been formed to achieve the motion of simulated human mastication. Some real human mastication motion have been tracked and used as targeted trajectories for the robot to reproduce. Several experiments have been executed to measure the jaw movements and chewing forces. To reduce the vibration of the actuators and protect sensitive linkage part of the robot, the traditional PID control and some advanced control theories were implemented to achieve most effective efforts. A mathematical model was also designed at the first stage when a test actuator powered by brushless motor was formed; however, it is finally proven not well controlled in either mechanical and control ways. Major features of the built robot including the motion control system are presented and tested. Experimental results including free chewing, soft-food and hard-food chewing are given where the foods are simulated by foam and hard objects. Also the joint actuations and driving torques required are compared for the chewing of different foods. In conclusion, tracking motion control has been attempted on the physical robot and a solution to the trajectory control has been developed.

The scarcity of fossil energy resources in conjunction with increasing demand has recently created record commodity price rises. Global warming and dimming are some of the harmful effects of increasing use of this resource. Furthermore, fossil fuel exhaust emissions, produced in internal combustion engines (ICE), generate significant health concerns. For decades, fears and numerous alarms have been raised regarding these problems. Many researchers believe that hydrogen would be an ideal alternative solution. Reduced fossil fuel consumption and lower thermal emanations (CO, CO2, HC and NO) are expected if hydrogen is used, as a principal or supplementary fuel, in standard ICE’s. However, hydrogen dual-fuel use has historically been associated with injection and/or detonation problems. Direct injection (DI) strategy, in spark and compression engines, is commonly used to overcome some, but not all, of these difficulties. This experimental research investigated detonation free, diesel-hydrogen fuel consumptions, and exhaust emissions using an indirect injection (IDI) strategy in a generic compression diesel engine. A novel analogue Mechatronic Injection Unit (MICU) in conjunction with a multi point injection tactic (MPI) were devised to indirectly deliver low pressure hydrogen to a stationary Lister-Pitter diesel engine combustion chamber. The hydrogen injection system was created to be used as a generic dual-fuel kit. With off-the-shelf parts the MICU design was simple, robust, and purposeful in its function. The MICU component also formed an important element of a proposed innovative dual-fuel conversion kit. Nine hydrogen injection rates were tested. Diesel consumption savings were measured and the ‘effectiveness’ of hydrogen vitiated injection was computed. The research outcomes demonstrated that with a conventional diesel mechanical governor and an assumed engine compression ratio of 15.5, detonation free combustion can be achieved with low pressure hydrogen vitiation and enrichment . However, an injection rate limit existed above which detonation occurred. The study also demonstrated that through low pressure hydrogen vitiation and enrichment, diesel consumption savings were achieved. The research confirmed that the experimental fuel mass savings were lower than their expected/theoretical counterparts. The research particularly established that vitiation and enrichment effectiveness was only realised at low rather than high loads indicating that hydrogen achieved more than diesel mass substitutions. In this study a new confined area dual-fuel static emission testing procedure, coupled with an on-site use test cycle was proposed and termed the Dual-fuel fixed speed emission-testing guideline. Dry thermal emissions were measured, and both the cycle average and median dry- and wet-emissions were computed, substance/species comparisons were performed and conclusions were drawn. The shortcomings of the procedure however were also highlighted. Finally, the research established that one action or measure, such as dual-fuel hydrogen vitiation and enrichment, can not address all the environment and health concerns. Contrary to the common belief, green house gases, nitrogen oxides, hydrocarbons and opacity substances do not coincidently all increase and/or decrease. Indeed, this experiment demonstrated that although the diesel-hydrogen nitrogen monoxide (NO) wet-emissions at all injection rates were partially lower than the diesel baseline, carbon oxides, hydrocarbon emissions, opacity (N) and absorption coefficients (k) were higher. In other words, a measure taken to limit the harm done to human health can increase the damage to the environment and vice versa.