Thermomagnetic motors can represent an alternative for the conversion of heat into mechanical energy, limited by the critical transition temperature (TC) of the used magnetic materials. Thus, by using materials with a TC close to room temperature, the energy available in the form of low-grade heat sources can be converted into useful mechanical work. This thesis proposes the development of a thermomagnetic motor to be operated with heat sources at temperatures in the range from 343 to 353 K, and a heat sink at room temperature, using water as the heat transfer fluid, presenting a novel approach to the construction of thermomagnetic devices. The design of this thermomagnetic motor was developed with the intent of producing a rotary movement, working similarly to an electric stepper motor, where instead of the electromagnetic coils being activated by an electric current, plates of a magnetic material change their magnetization state, due to a change in their temperature caused by the heat transfer with the heat transfer fluid. The analysis of the thermomagnetic motor proposed was done with the adoption of an integrated approach of numerical simulation and experimental validation. The evaluation of the motor is divided into the three main physical phenomena it encompasses: the magnetic field source, the heat transfer processes involved in the change of temperature of the magnetic material, and the system dynamics and power production. Each of these systems was modeled using computational tools. These models were then validated according to the data measured, obtained from a test stand of an idealized thermomagnetic motor, and for a rotary thermomagnetic motor. This methodology allowed a more comprehensive understanding of the critical working principles of the motor developed, and with that a fast advancement of the technology through a validated computational model. The computational models helped to identify the critical components to be improved in the development of these motors. These parameters can be guidelines for the design of thermomagnetic motors. One of the ways identified to produce a significant performance improvement, in the simulations, was the adoption of a control strategy that promotes the regeneration of heat in the plates of magnetic material, through which an improvement in the efficiency of 2.7 times could be achieved. / Motores termomagnéticos representam uma alternativa para a conversão de calor em energia mecânica, limitada apenas pela temperatura crítica da transição termomagnética (TC) dos materiais magnéticos. Ao usar materiais com TC próximo à temperatura ambiente, pode-se realizar a conversão da energia contida nas chamadas fontes pobres de calor, produzindo trabalho mecânico útil. Esta tese propõe o desenvolvimento de um motor termomagnético para operação com fontes de calor com temperaturas entre 343 e 353 K, e resfriamento à temperatura ambiente, utilizando a água como fluído de troca térmica, apresentando uma abordagem inovadora para dispositivos termomagnéticos. O motor foi projetado para produção de movimento rotativo de um eixo, per meio de um princípio similar ao de um motor de passo, no qual em vez de bobinas ativadas pela passagem de corrente elétrica, placas de material magnético sofrem uma mudança em seu estado de magnetização, devido à mudança de temperatura, causada pela troca de calor com a água. A análise do motor termomagnético proposto foi realizada com a adoção de uma abordagem integrada de simulações numéricas e validação experimental, dividindo a avaliação dos motores nos três principais fenômenos físicos envolvidos em seu funcionamento: a fonte de campo magnético, o processo de troca térmica envolvido na mudança de temperatura do material magnético, a dinâmica do sistema e produção de potência. Cada um destes sistemas foi modelado usando ferramentas computacionais. Os resultados obtidos foram então validados utilizando dados experimentais, obtidos a partir da construção e caracterização de uma bancada de testes para um motor termomagnético idealizado, e também para o motor termomagnético rotativo construído. Esta metodologia propiciou maior entendimento das funções críticas do motor desenvolvido, e possibilitou ainda sua otimização, através do estudo dos modelos computacionais validados. Os parâmetros obtidos ajudaram a identificar componentes críticos para melhoria no projeto do motor rotativo construído, e servem também como guias gerais para projetos de motores termomagnéticos. Um dos componentes com elevado potencial de melhoria foi a adoção de uma estratégia de controle para a regeneração do calor nas placas de material magnético, o que possibilitou, nas simulações, uma melhoria até 2,7 vezes na eficiência.

Multi-agent multi-team systems are commonly seen in environments where hierarchical layers of goals are at play. For example, theater-wide combat scenarios where multiple levels of command and control are required for proper execution of goals from the general to the foot soldier. Similar structures can be seen in game environments, where agents work together as teams to compete with other teams. The different agents within the same team must, while maintaining their own ‘personality’, work together and coordinate with each other to achieve a common team goal. This research develops strategy-based multi-agent multi-team systems, where strategy is framed as an instrument at the team level to coordinate the multiple agents of a team in a cohesive way. A formal specification of strategy and strategy-based multi-agent multi-team systems is provided. A framework is developed called SiMAMT (strategy- based multi-agent multi-team systems). The different components of the framework, including strategy simulation, strategy inference, strategy evaluation, and strategy selection are described. A graph-matching approximation algorithm is also developed to support effective and efficient strategy inference. Examples and experimental results are given throughout to illustrate the proposed framework, including each of its composite elements, and its overall efficacy. This research make several contributions to the field of multi-agent multi-team systems: a specification for strategy and strategy-based systems, and a framework for implementing them in real-world, interactive-time scenarios; a robust simulation space for such complex and intricate interaction; an approximation algorithm that allows for strategy inference within these systems in interactive-time; experimental results that verify the various sub-elements along with a full-scale integration experiment showing the efficacy of the proposed framework.