Abstract Introduction A ventricular assist device (VAD) is an electromechanical pump used to treat heart failures. For designing the physiological control system for a VAD, one needs a mathematical model and its related parameters. This paper presents a characterization procedure for determining the model parameter values of the electrical, mechanical, and hydraulic subsystems of a pediatric Rotary Blood Pump (pRBP). Methods An in vitro test setup consisting of a pRBP prototype, a motor driver module, an acrylic reservoir, mechanical resistance and tubings, pressure and fluid flow sensors, and data acquisition, processing, and visualization system. The proposed procedure requires a set of experimental tests, and a parameter estimation algorithm for determining the model parameters values. Results The operating limits of the pRBP were identified from the steady-state data. The relationship between the pressure head, flow rate, and the rotational speed of the pRBP was found from the static tests. For the electrical and mechanical subsystems, the dc motor model has a viscous friction coefficient that varies nonlinearly with the flow. For the hydraulic subsystem, the pressure head is assumed to be a sum of terms related to the resistance, the inertance, the friction coefficient, and the pump speed. Conclusion The proposed methodology was successfully applied to the characterization of the pRBP. The combined use of static and dynamic tests provided a precise lumped parameter model for representing the pRBP dynamics. The agreement, regarding mean squared deviation, between experimental and simulated results demonstrates the correctness and feasibility of the characterization procedure.

In this paper the development of an experimental test bench to analyze and control the strain of a flexible aluminum beam subjected to external disturbances is described. In the proposed platform, strain-gauges are used to measure the strain of the beam in a single cantilever mode while Ni-Ti-Cu Shape Memory Alloy (SMA) wires are used as force actuators. Data acquisition and control system are implemented with an ADuC microcontroller. The response of the structure in open-loop was used to identify the mathematical model of the system. To find the appropriate controller and to reach the best performance of the system, it was used techniques of direct tuning (pole-zero cancellation) in the identified model. The PI controller has been used to control the strain of the beam for different types of reference signals, as square, sinusoidal and triangular. The frequencies of the reference signals have been varied to observe to which bandwidth the system can respond. Experimental results are used to demonstrate the usefulness of the PI controller in the proposed smart structure.

A detecção da incrustação em sistemas de dutos é um problema persistente e requer uma demanda pertinente para as indústrias químicas, petrolíferas, alimentícias e farmacêuticas. A incrustação é um processo de deposição de materiais sólidos dissolvidos orgânicos e outros materiais pesados nos fluidos transportados ou em suspensão sobre as superfícies das paredes internas em sistemas de transporte de fluidos. Este trabalho apresenta resultados da pesquisa de excitação do teste do martelo para análise de vibrações utilizando testes não-invasivos para detecção de incrustação em tubulações. Dados da vibração foram analizados na presença de uma camada de incrustação no interior dos tubos usando um acelerometro e um microfone para detecção. Com a análise dos resultados obtidos é possível detectar o processo de incrustação, nas tubulações monitoradas, com e sem condições de carga, utilizando um microfone e um acelerômetro como sensores.

The fouling detection in duct systems is a persistent problem and remains a relevant demand for the chemical, oil, food and pharmaceutical industries. The fouling is a deposition process of heavy organic and other dissolved solid materials in the transported fluids or suspensions onto inner wall surfaces in fluid transport systems. This work presents research results of hammer test for vibration analysis using non-invasive tests to fouling detection in pipelines. Data were taken from the vibration in presence of an inner pipe fouling layer using an accelerometer and a microphone for detection. With the analysis of the obtained results is possible to detect the fouling process, in the monitored pipelines, with and without load conditions, using a microphone and an accelerometer as sensors.

The use of shape memory alloys (SMA) as smart structures and other modern applications require a previous evaluation of its performance under load as well as a training procedure. In general, these requirements lead to the design and assembly of a specific test bench. In this work, an experimental set-up was specially designed to perform the electro-thermomechanical characterization of SMA wires. This apparatus was used to determine the strain-temperature (epsilon - T) and electrical resistance-temperature (R - T) hysteretic characteristics curves of a Ti-Ni shape memory wire (90 mm in length and 150 µm in diameter) under mechanical load. The SMA wire is loaded by means of constant weights and a controlled system for injection of electrical power allows performing the heating-cooling cycles. The obtained hysteretic epsilon - T and R - T characteristics curves for some levels of applied loads are used to determine important shape memory parameters, like martensitic transformation temperatures, temperature hysteresis, temperature slopes and shape memory effect under load. These parameters were in accord with the ones found in literature for the studied SMA wires.