It is felt the position of the Scheffé polynomials as the primary, or sometimes sole recourse for practitioners of mixture experiments leads to a lack of enquiry regarding the type of blending behaviour that is used to describe the response and that this could be detrimental to achieving experimental objectives. Consequently, a new class of models and new experimental designs are proposed allowing a more thorough exploration of the experimental region with respect to different blending behaviours, especially those not associated with established models for mixtures, in particular the Scheffé polynomials. The proposed General Blending Models for Mixtures (GBMM) are a powerful tool allowing a broad range of blending behaviour to be described. These include those of the Scheffé polynomials (and its reparameterisations) and Becker's models. The potential benefits to be gained from their application include greater model parsimony and increased interpretability. Through this class of models it is possible for a practitioner to reject the assumptions inherent in choosing to model with the Scheffé polynomials and instead adopt a more open approach, flexible to many different types of behaviour. These models are presented alongside a fitting procedure, implementing a stepwise regression approach to the estimation of partially linear models with multiple nonlinear terms. The new class of models has been used to develop designs which allow the response surface to be explored fully with respect to the range of blending behaviours the GBMM may describe. These designs may additionally be targeted at exploring deviation from the behaviour described by the established models. As such, these designs may be thought to possess an enhanced optimality with respect to these models. They both possess good properties with respect to optimality criterion, but are also designed to be robust against model uncertainty.

Visualization tools are frequently used to help people understand everyday data in their lives. One such example is visualization in behaviour feedback tools. Behaviour feedback tools are used to try to help people improve their health or personal well-being or to carry out sound environmental sustainability practices. However, understanding and reasoning about personal data (e.g., pedometer counts, blood pressure readings or home electricity consumption) or gaining a deeper understanding of one's current practices and learning how to make a change can be challenging when using data alone. My literature review of this field showed that two of the main challenges in actual practice are providing a context in which to reason about the data and reducing the cost of maintenance to fit those tools into everyday life routines. Thus, I propose to integrate time-varying feedback data within a personal digital calendar. This combination of calendar and feedback data can provide contextual information to interpret data and make the data accessible in an attentionally ambient way that is suitable for maintaining awareness. I propose that the familiarity and common practice of using digital calendars can minimize the cost of learning and maintenance for people and easily fit into one's daily life routines. The viability of this approach was confirmed in my quantitative lab experiments. The results showed that visualization of feedback data integrated on a digital calendar is comprehensible, and it does not interfere with regular calendar use with proper visual encodings. After confirming the viability of my proposal, I implemented the on-calendar visualization as a web application that was synchronized with Google Calendar API and a real-time feedback data stream. To further investigate this approach in a real life situation, I deployed the application in the field for longitudinal field studies: two case studies as pilot deployment and an eight-week field study. Results showed that people liked the idea of integrating feedback data into their personal digital calendars. It required a low cost in learning and maintenance. The calendar events provided rich context for people to visualize and reason about their feedback data. The design enabled people to quickly identify and explain repeated patterns and anomalies. Meanwhile, I found that people's existing information use habits (in this case, how they use digital calendars) can highly influence the effectiveness of the feedback design. Moreover, I derived a feedback model that identifies basic components in feedback design and illustrates the role of feedback tools. With that I articulated possible design barriers that could prevent ongoing use of feedback tools. Reflecting on the effects of the on-calendar design approach, I discussed design implications inspired by this work. This work introduces a reflective approach in feedback design that can easily fit into people's existing information ecosystem (specifically, a personal digital calendar in this work). The main contributions of this thesis are: the first systematic literature review of personal visualization design used in everyday life; the design and implementation of an on-calendar design that integrates feedback data on people's personal digital calendars to provide context for reasoning and support easy access for ongoing use; the extended definition of ambience from spatial location to attentional demand; a viability study to confirm the on-calendar design approach; longitudinal studies to investigate the effects of the on-calendar design approach and the feedback model of design mechanism to inspect ongoing factors in feedback designs. / Graduate / 0984, 0384 / dhuangca@gmail.com

Neste trabalho, estudaram-se os mecanismos de desgaste por deslizamento dos aços AISI 304 e AISI 316 em função da carga normal (de 6 N a 20 N) e da velocidade tangencial (de 0,07 m/s a 0,81 m/s). De acordo com o planejamento fatorial 23, realizaram-se ensaios de desgaste em equipamento convencional, do tipo pino-contra-disco. Foram usadas técnicas de análise das superfícies e das partículas após o desgaste: microscopia eletrônica de varredura (MEV), difração de raios-X, espectroscopia Mössbauer, rugosidade, temperatura e dureza instrumentada. Concluiu-se que os mecanismos de desgaste por deslizamento para os aços AISI 304 e AISI 316 são dominados pela deformação plástica (desgaste por oxidação de partículas metálicas, desgaste adesivo e desgaste misto). A variação da taxa de desgaste dos dois materiais dependeu do efeito da interação entre os níveis de carga normal e velocidade tangencial. Por meio do planejamento composto central, foi possível obter um modelo empírico da variação da taxa de desgaste em função da carga normal e da velocidade. / In this work, sliding wear mechanism of AISI 304 and AISI 316 austenitic stainless steels were studied as a function of the applied load (from 6 N to 20 N) and the tangential velocity (from 0.07 m/s to 0.81 m/s). Following the 23 factorial design, wear experiments were performed using a conventional pin-on-disc machine. Worn surfaces and wear debris analysis techniques were used: scanning electron microscopy (SEM), X-ray diffraction, Mössbauer spectroscopy, stylus profiling, surface temperature measurement and instrumented indentation. Plasticity-dominated wear (metallic debris oxidation, adhesive wear and mixed wear) are the sliding wear mechanisms for AISI 304 and AISI 316 steels. The wear rate behavior depended on interaction effect between applied load and tangential velocity. An empirical model of wear rate as a function of applied load and tangential velocity was obtained by means of the central composite design.

Neste trabalho, estudaram-se os mecanismos de desgaste por deslizamento dos aços AISI 304 e AISI 316 em função da carga normal (de 6 N a 20 N) e da velocidade tangencial (de 0,07 m/s a 0,81 m/s). De acordo com o planejamento fatorial 23, realizaram-se ensaios de desgaste em equipamento convencional, do tipo pino-contra-disco. Foram usadas técnicas de análise das superfícies e das partículas após o desgaste: microscopia eletrônica de varredura (MEV), difração de raios-X, espectroscopia Mössbauer, rugosidade, temperatura e dureza instrumentada. Concluiu-se que os mecanismos de desgaste por deslizamento para os aços AISI 304 e AISI 316 são dominados pela deformação plástica (desgaste por oxidação de partículas metálicas, desgaste adesivo e desgaste misto). A variação da taxa de desgaste dos dois materiais dependeu do efeito da interação entre os níveis de carga normal e velocidade tangencial. Por meio do planejamento composto central, foi possível obter um modelo empírico da variação da taxa de desgaste em função da carga normal e da velocidade. / In this work, sliding wear mechanism of AISI 304 and AISI 316 austenitic stainless steels were studied as a function of the applied load (from 6 N to 20 N) and the tangential velocity (from 0.07 m/s to 0.81 m/s). Following the 23 factorial design, wear experiments were performed using a conventional pin-on-disc machine. Worn surfaces and wear debris analysis techniques were used: scanning electron microscopy (SEM), X-ray diffraction, Mössbauer spectroscopy, stylus profiling, surface temperature measurement and instrumented indentation. Plasticity-dominated wear (metallic debris oxidation, adhesive wear and mixed wear) are the sliding wear mechanisms for AISI 304 and AISI 316 steels. The wear rate behavior depended on interaction effect between applied load and tangential velocity. An empirical model of wear rate as a function of applied load and tangential velocity was obtained by means of the central composite design.