As engineers gain experience and become experts in their domain, the structure and content of their knowledge changes. Two studies are presented that examine differences in knowledge representation among freshman and senior engineering students. The first study examines recall of mechanical devices and chunking of components, and the second examines whether seniors represent devices in a more a...

This paper investigates the applicability of an electromagnetic generator with repulsively stacked magnets for harvesting energy from traffic induced bridge vibrations. First, the governing equation for electromechanical coupling is presented. The magnetic field for repulsive pole arrangements is discussed and the model is validated from magnet falling test. The detailed design, fabrication, an...

A silicon micromachined deformable mirror QiDM) has been developed by Boston University and Boston Micromachines Corporation (BMC). The pDM employs a flexible silicon mirror supported by mechanical attachments to an array of electrostatic parallel plate actuators. The integrated system of mirror and actuators was fabricated by surface micromachining using polycrystalline silicon thin films. The...

This paper describes an electroactive polymer robot with ray-like pectoral fins. Electroactive polymers are materials that change their geometry in response to electric field and can be used to replace electromechanical devices. The aim of this study is to show that these materials can be used to build more complicated devices and the behaviour of these devices can be coordinated to some extent...

Capacitive micromachined ultrasonic transducers ~CMUTs!, introduced about a decade ago, have been shown to be a good alternative to conventional piezoelectric transducers in various aspects, such as sensitivity, transduction efficiency, and bandwidth. In this paper, we discuss the principles of capacitive transducer operation that underlie these aspects. Many of the key features of capacitive u...

Micro-electromechanical system (MEMS) devices are small compared to normal mechanical devices, but they are still large compared to the wavelength of visible light. Thus, simple low-cost optical measurement techniques can be adapted for precise characterization of the motions of these small objects. The results of such measurements are important for veriication of simulations, especially for de...

We report and compare methods and apparatus for injection of pink bollworm, Pectinophora gossypiella (Saunders), embryos. Injection with an electromechanical device resulted in 59% survival of embryos. Previous techniques relying on a mechanical manipulator resulted in 8% survival. Pink bollworm (PBW) embryo injection technology is based in part on methods developed for injection and genetic tr...

Energy harvesting is the process of capturing energy existing in the environment of a wireless device in order to power its electronics without the need to manually recharge the battery. By replenishing on-board energy storage autonomously, the need to recharge or replace the battery can be eliminated altogether, enabling devices to be placed in difficult-toreach areas. Vibration-based energy h...

In this work the design, fabrication and testing of the first 3D-printed and wet metallized capacitive z-axis accelerometer with a volume of 3.4 cm × 8 mm × 2.5 mm is presented. Preliminary results well match the modelling, both in terms of electromechanical parameters and of measured sensitivity, thus validating the proposed concept and fabrication process. With a spring thickness of 300 μm an...