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Flow pumps have been developed for classical applications in Engineering, and are important instruments in areas such as Biology and Medicine. Among applications for this kind of device we notice blood pump and chemical reagents dosage in Bioengineering. Furthermore, they have recently emerged as a viable thermal management solution for cooling applications in small-scale electronic devices. This work presents the performance study of a novel principle of a piezoelectric flow pump which is based on the use of a bimorph piezoelectric actuator inserted in fluid (water). Piezoelectric actuators have some advantages over classical devices, such as lower noise generation and ease of miniaturization. The main objective is the characterization of this piezoelectric pump principle through computational simulations (using finite element software), and experimental tests through a manufactured prototype. Computational data, such as flow rate and pressure curves, have also been compared with experimental results for validation purposes.

Precision ”ow pumps have been widely studied over the last three decades. They have been applied in the areas ofBiology, Pharmacy and Medicine in applications usually related to the dosage of medicine and chemical reagents.In addition, thermal management solu tions for electronic devices have also been recently developed using thesekinds of pumps oering better performance with low noise and low power consumption. In previous works waspresented the working principle of a pump based on th e use of a bimorph piezoelect ric actuator inserted in a”uid channel to generate ”ow. This work presents a novel con“guration of piezoelectric ”ow pumps using abimorph piezoelectric actuator of dierent aspect ratio. Se nsibility studies of the rectangular cross-sectional areachannel are conducted computationally (CFD) and three parameters are investigated: resonance frequency andoscillation amplitude of the piezoelectric actuator, and pressure inside the channel. Also, experimental tests areconducted to verify the in”uence of clamps rigidity and actuators insulator. The experimental results showthat improving these two aspects it is possible to achieve higher ”ow rates.Keywords: Flow Pump, Bimorph Piezoelectric Actua tor, CFD, Aspect Ra tio, Micro”uidics

The microchips inside modern electronic equipment generate heat and demand, each day, the use of more advanced cooling techniques as water cooling systems, for instance. These systems combined with piezoelectric flow pumps present some advantages such as higher thermal capacity, lower noise generation and miniaturization potential. The present work aims at the development of a water cooling system based on a piezoelectric flow pump for a head light system based on LEDs. The cooling system development consists in design, manufacturing and experimental characterization steps. In the design step, computational models of the pump, as well as the heat exchanger were built to perform sensitivity studies using ANSYS finite element software. This allowed us to achieve desired flow and heat exchange rates by varying the frequency and amplitude of the applied voltage. Other activities included the design of the heat exchanger and the dissipation module. The experimental tests of the cooling system consisted in measuring the temperature difference between the heat exchanger inlet and outlet to evaluate its thermal cooling capacity for different values of the flow rate. Comparisons between numerical and experimental results were also made.

Precision flow pumps have been widely studied over the last three decades. They have been applied in the areas of Biology, Pharmacy and Medicine in applications usually related to the dosage of medicine and chemical reagents. In addition, thermal management solutions for electronic devices have also been recently developed using these kinds of pumps offering better performance with low noise and low power consumption. In a previous work, the working principle of a pump based on the use of a bimorph piezoelectric actuator inserted in a fluid channel to generate flow was presented. In this work, a novel configuration of this piezoelectric flow pump that consists of a flow pump using two bimorph piezoelectric actuators in parallel configuration has been studied and it is presented. This configuration was inspired on fish swimming modes. The complete cycle of pump development was conducted, consisting in designing, manufacturing, and experimental characterization steps. Load-loss and flow rate characterization experimental tests were conducted, generating data that allows us to analyze the influence of geometric parameters in the pump performance. Comparisons among numerical and experimental results were made to validate the computational results and improve the accuracy of the implemented models.

Precision flow pumps have been widely studied over the last three decades. They have been applied as essential components in thermal management solutions for cooling electronic devices offering better performance with low noise and low power consumption. In this work, a novel configuration of a miniature piezoelectrically actuated flow pump with the purpose of cooling a LED set inside a head light system for medical applications has been studied and it will be presented. The complete cycle of pump development was conducted. In the design step, the ANSYS finite element analysis software has been applied to simulate and study the fluid-structure interaction inside the pump, as well as the bimorph piezoelectric actuator behavior. In addition, an optimization process was carried out through Altair Hyperstudy software to find a set of parameter values that maximizes the pump performance measured in terms of flow rate. The prototype manufacturing was guided based on computational simulations. Flow characterization experimental tests were conducted, generating data that allows us to analyze the influence of frequency and amplitude parameters in the pump performance. Comparisons between numerical and experimental results were also made.

Foi estudado o mecanismo de resistência por não-preferência do biótipo C do pulgão-verde-dos-cereais, Schizaphis graminum (Rondani, 1852) em 18 genótipos de trigo (Triticum aestivum L.). O ensaio, em delineamento completamente casualizado com 15 repetições, foi conduzido em câmara de crescimento, com temperatura, umidade relativa e fotofase controladas. Os genótipos foram semeados de forma circular e aleatória e submetidos durante 96 horas a uma população de 90 indivíduos. Os parâmetros avaliados foram o número de pulgões/planta, em intervalos de 24 horas, o percentual de área foliar amarelada e o tipo de mancha causada pelo pulgão. Os resultados evidenciam que o mecanismo de não-preferência foi maior na cultivar Trigo BR 36 e nas linhagens PF 86418, PF86423, PF 86413 e PF 86411, as quais também apresentam efeito de antibiose sobre a espécie.