Monitoring of aquatic life is important for assessing long-term impacts on activities associated with fish stock and migration. One promising approach for long-term monitoring involves the development of self-powered telemetry devices capable of powering themselves by harnessing energy from the fish body undulations using implanted devices or from fluid motions generated by fish swimming using external devices. One of the latter devices is a broadband low frequency nonlinear bistable energy harvester. This cost-effective harvester has been inspired from the doubly curved leaf blades of a Venus-fly trap. This work ex- amines the static behavior of such a bio-inspired bistable energy harvester by analyzing its force-displacement characteristics. The objective is to identify crucial design parameters to optimize the harvester's performance for potential application in self-powered fish telemetry tags. The unique characteristics of the hysteresis loop and snap-through discontinuity of the bistable structure are investigated using experimentation and finite element analysis. The finite element model is found to qualitatively replicate experimental observations. Addition- ally, geometrical and assembly parameters that affect the force-displacement behavior of the harvester are identified. A sensitivity analysis is performed to determine the effect of the aspect ratio, buckling displacement and thickness of the proposed harvester on the static force-displacement curve. The sensitivity analysis has highlighted that the assembly and geometric parameters of the bistable structure affect multiple aspects of the force-displacement behavior simultaneously. Hence, analytical modeling has been attempted using the theory of lateral torsional buckling to further investigate the complex influence of the said parameters. / Master of Science / With the ongoing pursuit to enhance quality of life and accommodate the needs of a growing population, water resources are increasingly being used for various economic activities such as energy production, fish farming, and transportation, among others. Fish telemetry serves as a valuable tool to understand the long-term ecological impacts of such economic activities to ensure their sustainable growth. Taking inspiration from the leaf blades of the Venus flytrap an innovative, cost-effective nonlinear system with the potential to be integrated into telemetry tags is developed. This unique system scavenges energy from the ambient environment to power telemetry tags thus making telemetry tags self sustaining and removing the reliance on batteries. This study delves into the behavior of this proposed system, aiming to optimize its performance for potential use in self-powered fish telemetry tags. Through a comprehensive approach involving experimentation, numerical simulations, and analytical modeling, key design parameters influencing the efficiency of the energy harvester are identified. The findings highlight how assembly and geometric factors impact the performance of the system. This research offers insights that could lead to significant advancements in aquatic life monitoring technology, facilitating more effective and sustainable management of water resources.

[pt] O tema abordado neste trabalho é a observação e análise, em regime permanente e dinâmico, da ocorrência de um fenômeno que já foi observado em condições reais de operação do sistema elétrico brasileiro, que é a relação oposta à usual entre a grandeza controlada e a grandeza controladora. Nestes caso, mesmo que haja margem de recursos para manter a tensão controlada, ela não é útil. Por exemplo, uma diminuição na relação de transformação num transformador de tapes variáveis, com intuito de aumentar a tensão controlada acaba por reduzí-la, até que os limites de troca de tapes sejam atingidos ou o sistema entre em colapso. Para demonstrar a existência do problema, foram executadas simulações, em regime permanente e dinâmico, e verificado o efeito do controle de tensão por um transformador com tapes variáveis e por compensadores estáticos de potência reativa, situações corriqueiras de um sistema de potência. Foram demonstradas situações em que foi possível verificar a mudança da região de operação. Para a análise em regime permanente foi utilizado um algoritmo de fluxo de carga, e para a análise dinâmica, uma simulação no domínio do tempo. Nas simulações envolvendo transformadores de tapes variáveis, foi possível verificar a existência o efeito reverso da ação de controle de tensão nas análises estática e dinâmica. Nas simulações utilizando o compensador estático de potência reativa houve divergência entre os resultados das duas análises. / [en] This work presents the observation and analysis, in steady state and dynamic performance, of the phenomenon already observed in real operation conditions of the Brazilian Electric System, which is the opposite relationship between the controlled value and the target value. In this case, even if the resources have margin to keep the voltage controlled, this is not useful. For example, the reduction in the turn ratio on load tap changer transformer, with the aim of increase in the controlled voltage, result in its reduction, until the tap changer limit is reached or the system is led to the collapse. To demonstrate the existence of this problem, steady state and dynamic performance simulations were done, and the voltage control effect by on load tap changer transformer and static var compensator , current situations in a power system. Several situations where is possible verify the operation region changing was demonstrated. For steady state analysis was used a load flow algorithm and, for the dynamic analysis, a time domain simulation. In the simulations with on load tap changer transformer, it was possible to verify the existence of the reverse effect of the voltage control action in the static and dynamic analysis. In the simulations using static var compensator, a divergence was found between the results in the two analyses.

This Diploma Thesis is dedicated to stress analysis of carrier swap bodies Mega 25 with maximum technical weight 27 000 kg and has been worked out in corporation with ZDT Nové Veselí company. The aim of this work is to stress analysis of trailer in various burdensome conditions. The first section of the Thesis is occupied with original design and burdensome condition. Then, according to these states gained strength to control the finite element method, implement and then modify the design including design of new drawbar and then create selected construction drawings prepared.