This thesis presents a novel distributed control method which allows a collection of independently mobile robotic units, with two or three dimensional movement, to self-assemble into self-repairing hierarchical structures. The proposed method utilises a simple model of the cellular adhesion mechanisms observed in biological cells, allowing the robotic units to form virtually bonded aggregates which behave as predicted by Steinberg’s differential adhesion hypothesis. Simulated robotic units based on the design of the subaquatic HYDRON module are introduced as a possible platform on which the model can be implemented. The units are used to carry out a detailed investigation of the model behaviour and parameter space focusing on the two main tasks of rounding and sorting in both two and three dimensions. These tasks assess the model’s ability to reach a thermodynamically stable configuration when the aggregates consist of either a single population of units or multiple populations of units with differing adhesive properties. The results are analysed in detail with particular attention given to the role of random movements in determining the overall performance, and demonstrate that this model provides a very robust solution to these complex tasks. Finally, a possible extension of this work is presented in which the original model is combined with a genetic regulatory network controller. The performance of this composite is evaluated, and the benefits of this hybrid approach, in which a powerful control system manipulates a robust self-organising behaviour, are discussed.

In the manufacturing industry, parts are created with high demands on their mechanical properties. To avoid surface defects, components are over-dimensioned and then machined to the desired size. This will give rise to material waste and extra processing steps. Therefore, it is of interest to investigate methods to repair these surface defects without the need of over-dimensioning. In this thesis work, different strategies for localized electrochemical deposition have been investigated with respect to their ability to perform local repair of surface defects. The concepts that have been studied include the application of a microanode, a confined bath, and of liquid marbles. The different methods were tested and the process parameters were optimized to achieve good quality deposits at sufficient growth rates. The best deposits were then further characterized with respect to grain size distribution, crystal orientation and surface quality. The ability to repair a surface defect was also studied along with the possibility of producing thicker deposits. The confined bath method was the most promising concept. At a current density of 3.5 A/dm2, a good quality deposit was achieved. The crystal orientations proved to be random and the average grain size was 115 ± 61 nm. A surface defect with a depth of 33.0 µm and a width of 19.8 µm was successfully repaired using this local deposition method. However, the technique needs further development for the desired application in manufacturing industry.

In the current research project the functions of self-initiated self-repairs in an advanced Japanese language classroom were investigated. From the reviewed literature it was found that repairing is possible through monitoring, which includes error detection, and involves attention and memory. Therefore, data was collected on the abilities of the participants in the current research project to repair, monitor and their attention levels and memory. There were seven methods used to collect data; participant observation, classroom interaction tape recordings, a questionnaire, stimulated recall interviews, attention test, memory and attention test and proficiency level assessments. From the participant observation, classroom interaction tape recordings and stimulated recall interviews data was collected on the repairs that the participants made and the way in which they monitored was explored. The questionnaire revealed relevant background information, such as, number of years the participants had studied Japanese, which supplemented other information collected. The attention test and memory and attention tests were used to obtain information on the participants’ perceptions of their levels of attention and their actual levels of attention and memory respectively. The final data collected was on the participants’ own perceptions of their speaking proficiency levels in Japanese and an independent judge’s evaluation of their levels. The results of the data collected on the way in which the participants repaired and monitored showed that overall the participants repaired and monitored in ways that had been discussed in previous research on repairing and monitoring. However, for the first known time, phenomena related to repairing and monitoring, which the researcher terms as communication strategies, are used frequently by the participants and also, that these communication strategies used and repairs made by the participants were not needed to be made. In other words, the participants in the current research project were often repairing errors that had not been made. As for the data collected on the participants’ attention levels and memory, no significant differences were found between the participants and neither did any differences reflect on the ways in which the participants repaired. From the proficiency level assessments, further evidence was found that supported previous research done on repairing and monitoring as well. Also, it was found that the participants under-estimated their levels of proficiency in comparison to the independent judge’s evaluations. Therefore, the participants both over repair and under estimate their Japanese speaking abilities. This is seen as detrimental to the participants’ performances in Japanese. Recommendations are made to use this data provided by Japanese language learners when repairing to guide instruction and to encourage learners to gain fluency by repairing less often than is thought necessary.

The objective of this research is to determine the thermal residual stresses and strains in bonded composite repairs on cracked metal structures. This work is an essential contribution to a fatigue damage initiation model for bonded composite repair, where knowledge of the initial stress/strain state after an elevated temperature cure is important. Furthermore, this work is an elementary part for the development of a generic certification approach to bonded composite repairs. Accounting properly for thermal residual stresses in test specimens and in real applications will assist in determining the true feasibility of a bonded composite repair. The objective of this work was realized in four stages of research. In the first stage, seven AMRL sandwich type composite bonded repair specimens were manufactured, of which one was instrumented by placing 44 strain gauges at eight planar locations and within five different interfaces. Residual strains at ambient temperature (including both thermal residual strains and other process induced strains) were measured during the manufacturing process. In the second stage, the stress free temperature for the repaired specimen was experimentally determined and the thermal residual strains measured as a function of operating temperature. In the third stage, a theoretical analysis was carried out to estimate the thermal residual stress and strain distributions in various bonded repairs. This analysis also addressed the effect of symmetrical disbonds around the crack. Finally, a finite element analysis was carried out to assess the limitations of the theoretical analysis as well as to provide a more detailed insight into the complex thermal residual stress and strain state of the AMRL sandwich type specimen. During this work it was found that high thermal residual strains (reaching 15% of the yield strain) are present in the bonded repair specimen at ambient temperature. Previous analysis schemes predicted results nearly 60% higher. The thermal residual strain versus temperature measurement showed that only very small changes in thermal residual strains occurred above 90°C leading to a defined effective stress free temperature of 85.8°C for the employed adhesive FM 73M. By utilizing an effective stress free temperature, a linear-elastic approach was used to model thermal residual stresses and strains in composite bonded repairs. Major achievements in the theoretical analysis include a linear-elastic closed form solution for tapered joints and reinforcements without the need for a numerical solution scheme, a stress field prediction ahead of the crack tip for the metal substrate of a bonded repair based on a concise complete solution of the classical fracture mechanics problem of a center crack in an infinite plate and, an extended Rose model for the prediction of the stress intensity factor of a bonded repair with symmetrical disbonds showing the severity of thermal residual stresses especially for partially disbonded composite repairs to cracked metal specimens. The key to precise predictions of thermal residual stresses in bonded composite repairs is the knowledge of the adhesive behaviour at elevated temperatures under thermal residual stress loading. A generic type specimen is presented which allows to investigate the relevant adhesive behaviour.

The objective of this research is to determine the thermal residual stresses and strains in bonded composite repairs on cracked metal structures. This work is an essential contribution to a fatigue damage initiation model for bonded composite repair, where knowledge of the initial stress/strain state after an elevated temperature cure is important. Furthermore, this work is an elementary part for the development of a generic certification approach to bonded composite repairs. Accounting properly for thermal residual stresses in test specimens and in real applications will assist in determining the true feasibility of a bonded composite repair. The objective of this work was realized in four stages of research. In the first stage, seven AMRL sandwich type composite bonded repair specimens were manufactured, of which one was instrumented by placing 44 strain gauges at eight planar locations and within five different interfaces. Residual strains at ambient temperature (including both thermal residual strains and other process induced strains) were measured during the manufacturing process. In the second stage, the stress free temperature for the repaired specimen was experimentally determined and the thermal residual strains measured as a function of operating temperature. In the third stage, a theoretical analysis was carried out to estimate the thermal residual stress and strain distributions in various bonded repairs. This analysis also addressed the effect of symmetrical disbonds around the crack. Finally, a finite element analysis was carried out to assess the limitations of the theoretical analysis as well as to provide a more detailed insight into the complex thermal residual stress and strain state of the AMRL sandwich type specimen. During this work it was found that high thermal residual strains (reaching 15% of the yield strain) are present in the bonded repair specimen at ambient temperature. Previous analysis schemes predicted results nearly 60% higher. The thermal residual strain versus temperature measurement showed that only very small changes in thermal residual strains occurred above 90°C leading to a defined effective stress free temperature of 85.8°C for the employed adhesive FM 73M. By utilizing an effective stress free temperature, a linear-elastic approach was used to model thermal residual stresses and strains in composite bonded repairs. Major achievements in the theoretical analysis include a linear-elastic closed form solution for tapered joints and reinforcements without the need for a numerical solution scheme, a stress field prediction ahead of the crack tip for the metal substrate of a bonded repair based on a concise complete solution of the classical fracture mechanics problem of a center crack in an infinite plate and, an extended Rose model for the prediction of the stress intensity factor of a bonded repair with symmetrical disbonds showing the severity of thermal residual stresses especially for partially disbonded composite repairs to cracked metal specimens. The key to precise predictions of thermal residual stresses in bonded composite repairs is the knowledge of the adhesive behaviour at elevated temperatures under thermal residual stress loading. A generic type specimen is presented which allows to investigate the relevant adhesive behaviour. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate

This thesis raises discussion about the importance of repairing, new urban meeting places and the use of artificial intelligence. Using AI as a tool, I have re-visioned rituals around taking care of ourselves and our objects. When we give a lot of value to the repeated habits of repairing ourselves and our objects, they become like rituals to us, containing a deeper meaning in our lives. The physical context of my project is in the Örnsberg industrial area in Stockholm, at the address Instrumentvägen 21. This area was established in 1938 and still now a lot of carpenters and other kind of industries are located there. For this reason it serves as a natural place to build an urban community dedicated for repairing and sharing knowledge.  During my process I have tested new visual artificial intelligence tools that emerged during the past year. I have aimed to find out how we as designers could use AI as a tool to help us in our work and to also find the parts in the process where human intelligence is irreplaceable. Since AI in the current extent is new and there are a lot of questions hanging around it, it is important that us designers try to understand it already now already in its early stages. This thesis is my starting point on that path.

Pallet repair and reinforcement with metal connector plates (MCPs) may reduce wood waste while providing pallet users with quality, economical pallets. The study objectives were to evaluate the effect of MCP repair and reinforcement on pallet performance, and to evaluate preliminary standards for repair and reinforcement of pallets with MCPs. Whole pallets and pallet components were tested. Stringers and notched segments were tested in static bending, while end feet were tested for resistance to fork tine impact. Whole pallets were evaluated with a test protocol that simulated the effects of long-term handling. Stringers, repaired at notch corners, had greater strength, but less stiffness than the original stringers. Notch reinforcement with MCPs resulted in stringers with greater strength and stiffness than equivalent unreinforced stringers. No consistent species-width effect was found for strength of plated stringers. MCP-repair of above-notch failures did not restore the original strength or stiffness of notched segments. However, these repairs may be satisfactory since above-notch failures are secondary in frequency of occurrence. No differences were found between performance of plates used to repair stringers and notched segments. Both repaired and reinforced end feet had greater impact resistance than the equivalent original or unreinforced end feet. Wood species, rather than stringer width, had a greater influence on MCP performance. In general, tests of whole pallets supported the results from component tests which suggests that component testing may be a practical means of assessing the effect of repair and reinforcement techniques on pallet performance. / Master of Science

Submitted by Oliveira Santos Dilzaná (dilznana@yahoo.com.br) on 2014-01-21T13:40:06Z No. of bitstreams: 1 VÍVIAN VOLKMER PONTES.pdf: 4564074 bytes, checksum: 60dcf7571f664deb09ea5711b8570d64 (MD5) / Approved for entry into archive by Ana Portela (anapoli@ufba.br) on 2014-02-03T14:22:59Z (GMT) No. of bitstreams: 1 VÍVIAN VOLKMER PONTES.pdf: 4564074 bytes, checksum: 60dcf7571f664deb09ea5711b8570d64 (MD5) / Made available in DSpace on 2014-02-03T14:22:59Z (GMT). No. of bitstreams: 1 VÍVIAN VOLKMER PONTES.pdf: 4564074 bytes, checksum: 60dcf7571f664deb09ea5711b8570d64 (MD5) / A experiência de uma perda gestacional involuntária representa uma ruptura da gestação em desenvolvimento, daquilo que se esperava e que estava na iminência de acontecer: o tornar-se mãe e o nascimento de um bebê. Deste modo, implica em descontinuidade do desenvolvimento do self, desafiando entendimentos e expectativas que haviam sido construídos acerca de si mesmo e do mundo. A repetição dessas rupturas ao longo da trajetória reprodutiva ameaça o sentido do self, intensifica o nível de ambivalência e maximiza a incerteza em relação ao futuro. O presente estudo consistiu em um aprofundamento teórico e empírico sobre como o self constrói continuidade através de rupturas sucessivas ao longo da trajetória reprodutiva. Implicou entender as dinâmicas do self dialógico no fluxo do tempo, e analisá-las com o intuito de identificar processos de reorganização do self a fim de se manter coeso – apesar das rupturas, das recorrentes descontinuidades. Tendo em vista esta problemática, optou-se por tratá-la a partir do referencial teórico do Construtivismo Semiótico-Cultural, uma perspectiva teórico-metodológica que focaliza a construção inter e intrapessoal da subjetividade humana individual. Como método, realizou-se um estudo de cunho etnográfico realizado em dois contextos distintos de assistência à saúde da mulher e/ou casal com diagnóstico de aborto de repetição, na cidade do Salvador/BA, sendo um vinculado à rede pública e o outro à rede privada. No que concerne às estratégias de coleta de dados, destaque especial foi concedido às entrevistas narrativas. Já com relação à análise dos dados, foi utilizado o Modelo de Equifinalidade de Trajetórias (TEM). Participaram deste estudo dez mulheres com história de perdas gestacionais recorrentes. Após a realização de comparações descritivas entre as trajetórias reprodutivas das participantes – com a finalidade de entender os processos de rupturas e reconstruções na cultura pessoal através da aplicação do TEM –, foi construído um conceito que pudesse oferecer generalidade para o específico dessa experiência. Afinal, a experiência recorrente de rupturas significativas, exige um tipo específico de processo semiótico, que no presente trabalho foi denominado de estratégias semióticas de reparação dinâmica do self. Essas estratégias, ao serem utilizadas, levam à construção de signos específicos – os signos reparadores –, que têm o poder de restaurar a conexão dos fragmentos da trajetória interrompida, construindo alguma articulação entre esses fragmentos e resgatando certo senso de continuidade. Os signos reparadores promovem, assim, a construção de significado para o momento presente, a reconstrução de significados atribuídos às experiências no passado (perdas anteriores) e nova orientação para a gama aceitável de construções de significados orientados para o futuro, conectando-os, relançando-os numa nova narrativa, sempre singular – e, de certo modo, unificada e coerente –, acerca de si mesmo, da sua própria vida e do seu próprio “destino”. The experience of an involuntary pregnancy loss represents a rupture related to what was expected and what was about to happen: becoming a mother and the birth of a baby. Thus, this event implies discontinuity the development of self, challenging understandings and expectations that had been built about the person and the world. The repetition of these ruptures along the trajectory reproductive threatens the sense of self, intensifies the level of ambivalence and maximizes uncertainty about the future. This study consisted in a theoretical and empirical deepening about how the self builds continuity through successive ruptures along the reproductive trajectory. It was set up understand the dynamics of the dialogical self in the flow of time, and analyze them in order to identify processes of reorganization of the self in order to remain cohesive - despite the ruptures, the recurrent discontinuities. In view of this problem, we chose to approach it from the theoretical framework of Semiotic-Cultural Constructivism, a theoretical-methodological framework that focuses on building inter and intrapersonal individual human subjectivity. As a method, the ethnographic study was conducted in two distinct contexts of health care for women and / or couples with a diagnosis of recurrent abortion, in Salvador / BA: one linked to the public network and another network private. Concerning data collection strategies, special attention was given to the narrative interviews. Regarding data analysis, we used the Trajectories Equifinality Model (TEM). The participants of study were ten women with a history of recurrent pregnancy loss. After conducting descriptive comparisons between reproductive trajectories of participants - in order to understand the processes of disruptions and reconstruction in personal culture through the application of TEM - was built a concept that could provide for the generality of this specific experience. After all, the recurring experience of significant disruptions requires a specific type of semiotic process, which in this work was named Semiotic Strategies of Dynamic Self-Repairing. These strategies, when used, lead to the construction of specific signs – repairing signs – who have the power to restore the connection of the fragments of the interrupted trajectory, building a link between these fragments and rescuing some sense of continuity. Repairing signs thereby promotes the construction of meaning for the present moment, the reconstruction of meanings assigned to experiences in the past (previous losses) and new guidance for the acceptable range of constructions of meaning future-oriented, connecting them, relaunching them into a new narrative, always singular - and somehow unified and consistent - about yourself, your own life and your own "destiny".

published_or_final_version / abstract / Civil Engineering / Master / Master of Philosophy

Chen, Junyu. / Thesis M.Phil. Chinese University of Hong Kong 2014. / Includes bibliographical references (leaves 56-61). / Abstracts also in Chinese. / Title from PDF title page (viewed on 25, October, 2016).