Manufacturing is currently experiencing a paradigm shift in the way that products are designed, produced and serviced. Such changes are brought about mainly by the extensive use of the Internet and digital technologies. As a result of this shift, a new industrial revolution is emerging, termed “Industry 4.0” (i4), which promises to accommodate mass customisation at a mass production cost. For i4 to become a reality, however, multiple challenges need to be addressed, highlighting the need for design for agile manufacturing and, for this, a framework capable of integrating big data analytics arising from the service end, business informatics through the manufacturing process, and artificial intelligence (AI) for the entire manufacturing value chain. This thesis attempts to address these issues, with a focus on the need for design for agile manufacturing. First, the state of the art in this field of research is reviewed on combining cutting-edge technologies in digital manufacturing with big data analysed to support agile manufacturing. Then, the work is focused on developing an AI-based framework to address one of the customisation issues in smart design and agile manufacturing, that is, prediction of potential customer needs and wants. With this framework, an AI-based approach is developed to predict design attributes that would help manufacturers to decide the best virtual designs to meet emerging customer needs and wants predictively. In particular, various machine learning approaches are developed to help explain at least 85% of the design variance when building a model to predict potential customer needs and wants. These approaches include k-means clustering, self-organizing maps, fuzzy k-means clustering, and decision trees, all supporting a vector machine to evaluate and extract conscious and subconscious customer needs and wants. A model capable of accurately predicting customer needs and wants for at least 85% of classified design attributes is thus obtained. Further, an analysis capable of determining the best design attributes and features for predicting customer needs and wants is also achieved. As the information analysed can be utilized to advise the selection of desired attributes, it is fed back in a closed-loop of the manufacturing value chain: design → manufacture → management/service → → → design ... For this, a total of 4 case studies are undertaken to test and demonstrate the efficacy and effectiveness of the framework developed. These case studies include: 1) an evaluation model of consumer cars with multiple attributes including categorical and numerical ones; 2) specifications of automotive vehicles in terms of various characteristics including categorical and numerical instances; 3) fuel consumptions of various car models and makes, taking into account a desire for low fuel costs and low CO2 emissions; and 4) computer parts design for recommending the best design attributes when buying a computer. The results show that the decision trees, as a machine learning approach, work best in predicting customer needs and wants for smart design. With the tested framework and methodology, this thesis overall presents a holistic attempt to addressing the missing gap between manufacture and customisation, that is meeting customer needs and wants. Effective ways of achieving customization for i4 and smart manufacturing are identified. This is achieved through predicting potential customer needs and wants and applying the prediction at the product design stage for agile manufacturing to meet individual requirements at a mass production cost. Such agility is one key element in realising Industry 4.0. At the end, this thesis contributes to improving the process of analysing the data to predict potential customer needs and wants to be used as inputs to customizing product designs agilely.

Linear friction welding (LFW) is known as an advanced technique to substitute fusion welding of joining Ni-based superalloys. However, due to the complex microstructural development caused by LFW, some unexplained issues still need to be solved, such as: influence of weld parameters (weld pressure, amplitude of oscillation, and frequency of oscillation) on the development of microstructural, microhardness, texture and residual stresses in LFWed IN718-IN713LC; impact of post-weld heat treatment (PWHT) on the microstructural and microhardness development; influence of rapid thermal cycle on the precipitate dissolution of IN718 and IN713LC; formation mechanisms of alumina inclusions (Al-oxides) on the weld interface. The present work aims to investigate these issues.

A major factor limiting the use and longevity of rare earth based magnetic materials is their susceptibility to aqueous corrosion and associated detrimental effects upon the magnetic properties of the material. This process was investigated through a combination of exposure to simulated environmental conditions and hydrogen absorption/desorption studies (HADS) in conjunction with magnetic characterisation. This study utilises NdFeB MQP-B melt-spun ribbon manufactured by Magnequench, in the form of MQI bonded magnets and also in its unbonded state as MQ powder. Specifically, it was concerned with how effective a variety of bonding media (epoxy resin,PTFE, zinc) and surface coatings (PTFE, Qsil, zinc LPPS, Dex-Cool) were at limiting the impact of aqueous corrosion in MQI bonded magnets. To characterise the effect of hydrogen absorption upon the magnetic properties of the MQP-B, hydrogen uptake was induced followed by a series of outgassing heat treatments with subsequent magnetic characterisation accompanied by HADS techniques performed after each outgas. This allowed comparisons to be made between the effects of aqueous corrosion process and hydrogen absorption upon the magnetic properties of the alloy. This study has clearly demonstrated the link between the abundance of environmental moisture and rate of Hci losses in MQI bonded magnets. In addition to this the key mechanism responsible for the degradation of magnetic properties has been identified. These losses have been attributed to the absorption of hydrogen generated by the dissociation of water in the presence of NdFeB during the aqueous corrosion process. It has been shown that the use of a bonding media that is impermeable to water can limit the effects of aqueous corrosion by limiting water access to the Magnequench particles (MQP) and also the positive effects of the use of suitable surface coatings has been shown to be effective for the same reason.

Titanium aluminide alloys are prone to extensive shrinkage porosity, particularly interdendritic layer porosity. This research aims to develop a better understanding of shrinkage porosity in Ti-46Al-8Nb alloy and how to minimize it. Practical measurements in conjunction with computer simulations were carried out in order to study the effects of cooling rate and temperature gradient on shrinkage porosity in Ti-46Al-8Nb investment castings, through investigating the influence of casting geometry, specifically mould taper on cylindrical bars, and preheating mould temperature on the macrostructure and the formation of shrinkage porosity. The interface heat-transfer coefficient of the ceramic shell/surroundings was determined using measured cooling curves obtained in 200 mbar of Argon and in vacuum. Furthermore, the alloy/mould interfacial heat transfer coefficient was estimated and was verified by comparing measured and predicted cooling curves of Ti-46Al-8Nb. The Niyama criterion function was validated to predict shrinkage-related porosity in Ti-46Al-8Nb castings, through either thermal or tilt-filling ProCastTM simulation models. Positions in a casting with Niyama values above 4 (°C. min)0.5cm-1; (3 (K. s)0.5mm-1); could be considered completely sound. The critical value of the Niyama function was 2 (°C. min)0.5cm-1; (1.5 (K. s)0.5mm-1); below which the position tested was susceptible to macroshrinkage porosity.

This research presents a new sensor structure, the coupled micro resonator array (CMRA) as an approach to reduce the complexity of large artificial nose sensing system. The aim is to exploit multiple resonant sensors with a simplified readout. The CMRA working principle is based on mass loading frequency response effect; the frequency response of the coupled resonators is a signature for the multiple sensors. The key research outputs are balanced effective mass of the coupled resonators for measurable response and broke the structure symmetry for unique frequency response pattern and stable structure eigenvectors to enhance the system odour discrimination. To develop the CMRA, the structure is modelled and analysed using finite element and lumped mass analysis. Using silicon-on-insulator material, the CMRA is fabricated in order to evaluate the performance. The effect of mass loading is tested by platinum mass deposition using focused ion beam technology (FIB). The inverse eigenvalue analysis was used to estimate the mass change pattern of the CMRA structure. The research also investigates effect of the manufacturing variations on the CMRA structure performance. With the finger print of the coupled frequency response, the output signal of N multiple resonant sensors is monitored by a single processor; hence, reducing the complexity of readout and signal processing system.

Many foods contain large amounts of saturated fatty acids (SaFa), which are considered unhealthy, and their presence in the diet is one of the contributing factors of cardio-vascular disease, obesity and the inherent risk of diabetes. It has become the driver of food producers to manufacture products with as little of these oils as they can. Reformulation work based on Elmlea whipping creams sought to address this issue, by which the ingredients of the principal formulation were taken and ever increasing levels of liquid oil were added, but keeping the total oil concentration at 34%. Many of its’ properties were tested and the optimum formulation was found to be that containing 20% hydrogenated and 14% liquid oil. Further formulation work was associated with another product: ice-cream. Ice-cream distribution, particularly with its transport over the Rocky Mountains in the US, poses a large problem. Taking ice cream across the Mountains involves travelling at altitudes in excess of 2000 metres and this leads to its expansion due to the reduced air pressures. The product can spoil in transit. Further instabilities arise when extruded from a freezer. This instability was studied extensively in this work. It was seen that larger drops in pressure and at a slower rate were more detrimental to the model foam structure than small pressure differences and a fast rate. The fast pressure release seemed to have less of a detrimental effect on the resultant bubble foam microstructure.

The present investigation has been focused on the design, deposition and characterisation of novel low-friction, wear-resistant multilayer nanocomposite CrAlTiCN coatings. Systematic materials characterisation and property evaluation were conducted on the as-deposited and oxidation-tested CrAlTiCN coatings, and the results are presented and discussed. It is possible to generate novel CrAlTiCN coatings with the carbon content up to 24.34 at% by closed-field unbalanced magnetron sputtering of graphite target. The microstructure of the CrAlTiCN coatings mainly depends on their carbon content. When the carbon content is low, carbon atoms are mainly dissolved in the fcc metastable phase (Cr, Al, Ti) (C, N); when the carbon content is high, the major carbon atoms will form amorphous carbon with a C-C bond state and in a sp\(^2\) dominated graphitic environment. Both the hardness and brittleness of CrAlTiCN coatings reduce with increasing the carbon content. When tested at room temperature under unidirectional sliding conditions, the friction coefficient and wear of the CrAlTiCN coatings decrease with the carbon content, and the thermal stability of CrAlTiCN coatings is similar to the CrAlTiN coating but better than graphite-like carbon coatings. The good performance of the new CrAlTiCN coatings can be attributed to the optimised design of the coating system: the Cr/Al for oxidation resistance, the amorphous C for lowfriction and the multi-layered nano-composite microstructure for high toughness.

Thesis (M.S.)--Brigham Young University. School of Technology, 2006. / Includes bibliographical references (p. 89-91).

La present tesi doctoral analitza l'evolució i els factors determinants de la competitivitat de les manufactures catalanes a la UE-25 en el període 1999-2004. La contribució principal del treball és l'aplicació de l'indicador del quality gap a l'anàlisi de la competitivitat. Aquest indicador, que es construeix a partir de les dades de comerç dels estats membres i de Catalunya amb la UE per a més de 10.000 productes manfuacturats, permet comparar la qualitat de les exportacions (estimada a partir del valor unitari) de cada un dels territoris amb la mitjana de la UE.L'anàlisi empírica, que s'emmarca en el debat actual sobre la competitivitat, s'estructura en quatre grans objectius:1. Analitzar la competitivitat de les manufactures catalanes a la UE de l'euro i l'ampliació i posar de relleu els problemes de competitivitat.2. Identificar els determinants dels problemes de competitivitat.3. Contrastar que el quality gap és un indicador rellevant de competitivitat.4. Analitzar els patrons de competitivitat de les manufactures catalanes a la UE amb al quality gap.Així mateix, les conclusions de la tesi doctoral es poden agrupar en quatre grans blocs:Un primer conjunt de conclusions té a veure amb la relació del quality gap i l'evolució de la competitivitat. Per als 25 estats membres es contrasta l'estreta relació entre capacitat d'innovació, productivitat i quality gap. A més, es contrasta que el quality gap permet explicar millor les diferències en productivitat que altres indicadors més habituals, com l'especialització intraindustrial o interindustrial. El quality gap també contribueix a explicar l'evolució de la taxa de cobertura exterior, en canvi la relació entre quality gap i evolució de la quota de mercat és menys directa, en un període marcat per l'ampliació de la UE als països de l'Europa central i oriental. En el període 1999-2004 Catalunya ha millorat el seu quality gap i la seva quota de mercat, però la seva taxa de cobertura s'ha mantingut estancada a uns nivells relativament baixos.El segon grup de conclusions està vinculat a la productivitat. A Catalunya els problemes de productivitat no s'expliquen tant per l'especialització interindustrial, que és similar a la de la UE, com per l'especialització intraindustrial, condicionada per una menor capacitat d'innovació. L'anàlisi realitzada apunta cap a un canvi en l'especialització de les exportacions manufactureres catalanes cap a sectors més intensius en tecnologia i amb una productivitat més elevada, però en els quals Catalunya està posicionada en un segment de qualitat inferior. El canvi d'especialització es detecta particularment en el comerç intraindustrial, amb una elevada i creixent tendència a l'especialització en el segment de qualitat inferior i en els mercats competitius en preus, que ha contribuït al deteriorament de la relació d'intercanvi en preus amb la UE.Un tercer grup de conclusions està relacionat amb el comerç de productes intermedis, que contribueix a explicar l'estancament de la taxa de cobertura. En el període 1999-2004 s'incrementa la propensió a importar de les empreses manufactureres catalanes i la qualitat de les importacions en relació amb les exportacions. La importació de productes intermedis de més qualitat afavoreix la millora del quality gap de les exportacions i la millora de la quota de mercat a la UE, però dificulta l'equilibri exterior de l'economia catalana.Finalment, l'indicador del quality gap aporta informació rellevant i addicional a la dels indicadors tradicionals de competitivitat i permet realitzar una anàlisi sistemàtica dels patrons nacionals de competitivitat a la UE a un nivell de desagregació elevat. / The present doctoral thesis analyses the evolution and the determining factors of the competitiveness of the Catalan manufacturing sector in the EU-25 in period 1999-2004. The main contribution of the work is the application of the quality gap indicator to the competitiveness analysis. This indicator allows to compare the quality of the exports of each one of the territories with the EU average through the comparison of the unit values of exports for more than 10.000 manufacturing products. The empirical analysis has four main objectives: 1. To analyse the competitiveness of the Catalan manufacturing sector in the EU and to point up the competitiveness problems. 2. To identify the determinants of the competitiveness problems. 3. To contrast that quality gap is a good indicator of competitiveness. 4. To analyse the patterns of competitiveness of the Catalan manufactures in the UE with the quality gap. The conclusions of the doctoral thesis can be grouped in four blocks. A first set of conclusions has to do with the relation between the quality gap and the competitiveness of the manufacturing sector. For the 25 member states we verify the narrow relation among innovation capacity, productivity and quality gap. In addition we verify that quality gap explains better the differences in productivity than other more habitual indicators, like the intraindustrial or interindustrial specialization. The quality gap also contributes to explain the evolution of the external balance, although the relation between quality gap and evolution of the EU market share is less direct, in a period marked by the EU enlargement to the Central and Eastern European countries. In the period 1999-2004 Catalan manufactures have improved their quality gap and their market share in the EU, but the trade deficit has remained high. The second group of conclusions is related to the productivity. In Catalonia the productivity problems are not explained so much by the interindustrial specialization, that is similar to the one of the EU, like by the intraindustrial specialization conditioned by a lower innovation capacity. The analysis for the period 1999-2004 points at a change in the specialization of the Catalan manufacturing exports towards sectors more intensive in technology and with higher productivity, but in which Catalonia is positioned in a lower quality segment. The change of specialization is detected particularly in the intraindustrial trade, with a high and increasing tendency to the specialization in the segment of inferior quality and in the markets dominated by price competition. A third group of conclusions is related to the trade of intermediate products, that contributes to explain the high Catalan trade deficit. In period 1999-2004 the Catalan manufacturing companies have increased their propensity to import and the quality of their imports in relation to exports. The higher quality of the intermediate products favours the improvement of the exports quality gap and consequently the improvement of the market share, but it makes difficult the external balance of the Catalan economy. Finally, the indicator of quality gap provides relevant and additional information to the one of the traditional competitiveness indicators and allows to make a systematic analysis of the national patterns of competitiveness in the UE at a high level of disaggregation.

Thesis (Ph. D.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 214-235).