Micro/nanoelectromechanical systems (MEMS/NEMS) provide the engineer with a powerful set of solutions to a wide variety of technical challenges. However, because they are mechanical systems, response times can be a limitation. In some situations, advanced engineered drive techniques can improve response times by as much as a thousand fold, significantly opening up the application space for MEMS/NEMS solutions.

Sailing yachts require an additional propulsion source beside the sails for emergencies to be manoeuvrable in absence of wind or in tight conditions such as ports. Typically, small inboard or outboard combustion engines serve this purpose. In the tropics, solar energy is abundantly available throughout the year, and therefore solarpowered electric motors are attractive alternatives to combustion engines. We explore the dimensioning of solar panels for such a boat and conclude that for a fixed desired range under electric power and a fixed available charging time, the required solar panel surface grows roughly proportional to the cube of the length of the boat, whereas the available surface for solar panels grows proportional to its square. Even in the tropics, solar power therefore ceases to be feasible as exclusive auxiliary power from a certain length of the boat upwards. To verify these conclusions, our team has converted one of the smallest available sailing yachts, a 7.7m long motorised sailing yacht to a carbon-neutral vessel by retrofitting it with a 2.0kW electric outboard motor and two 24V 200Ah marinised lithium-ion phosphate battery sets. Three 275 W mono-crystalline solar panels serve as cockpit roof and are mounted on a custom-built stainless steel truss. The battery lasts for 5 hours of continuous full throttle operations and can be fully charged by the solar panels in less than four days under typical light conditions in Singapore. The solar charging data can be monitored remotely by a newly developed web interface. The boat was converted in October 2014 and is currently the only carbon-neutral motorized sailing yacht in Singapore.

Electric motors powered with batteries that are charged by solar panels provide an attractive alternative to internal combustion engines as an auxiliary propulsion method for cruising sailing yachts, especially when shore electric power is not available. This project explores the conversion of existing yachts to the solarelectric alternative, making them quiet, clean and carbon neutral during operations. More specifically, we address the question under what circumstances currently available solar panels, controllers, batteries and motors present a viable option for converting conventionally powered cruising yachts to solar-electric auxiliary propulsion. We argue that small sailing yachts provide a more promising target for conversion than larger ones and that tropical conditions favour solar-electric propulsion. Thus, a small cruising sailing yacht operating in the tropics serves as a case study for conversion. The dimensions of the chosen boat, along with requirements on the desired range and charge time inform the choice of motor, battery and solar panels. We describe the design of a custom-made truss for solar panels, considering the required solar panel size, as well as ergonomic, aesthetic and mechanical design constraints. A finite element analysis of the truss simulates the wind load in severe weather conditions. We conclude with a preliminary evaluation based on test voyages in Singapore and Indonesia.

Semiconductor fabs are large, complex industrial sites with costs for a single facility approaching $10B. In this paper we discuss the possibility of putting the entire functionality of such a fab onto a single silicon chip. We demonstrate a path forward where, for certain applications, especially at the nanometer scale, one can consider using a single chip approach for building devices with significant potential cost savings. In our approach, we build micro versions of the macro machines one typically finds in a fab, and integrating all the components together. We argue that the technology now exists to allow one to build a Fab on a Chip.

Capacitive comb actuators are widely used as MEMS motors due to their long range of linear motion, low power consumption, and ease of fabrication. Here, we present data from a thin comb capacitive actuator where fringe fields contribute significantly to the device performance. We characterize the observed levitation effect and discuss two methods to control the out-of-plane forces: 1) by means of alternating the comb polarity; and 2) by using an additional electrode below the comb. Considering two alternative designs, it is shown how the levitation force can be mitigated. One design decreases the out-of-plane motion by a factor of two, but also reduces the lateral range. An alternative design proved successful in decreasing out-of-plane motion by 75%, while enhancing the in-plane displacement of the linear comb actuator by over 35%.

Matthias Imboden, Han Han, Thomas Stark, Evan Lowell, Jackson Chang, Flavio Pardo, Cristian Bolle, Pablo G. del Corro, and David J. Bishop Department of Electrical and Computer Engineering Department of Physics Division of Materials Science and Engineering Boston University, Brookline, Massachusetts 02446, USA Department of Mechanical Engineering Boston University, Boston, Massachusetts 02215, USA Bell Labs, Alcatel-Lucent, 600 Mountain Avenue, Murray Hill, New Jersey 07974, USA Instituto Balseiro, Centro Atómico Bariloche, Bariloche Río Negro 8400, Republic of Argentina

We present a micro-electromechanical system (MEMS) based method for the resist free patterning of nano-structures. Using a focused ion beam (FIB) to customize larger MEMS machines, we fabricate apertures as small as 50 nm on plates that can be moved with nanometer precision over an area greater than 20x20 {\mu}m^2. Depositing thermally evaporated gold atoms though the apertures while moving the plate results in the deposition of nanoscale metal patterns. Adding a shutter only microns above the aperture, enables high speed control of not only where but also when atoms are deposited. Using a shutter, different sized apertures can be selectively opened and closed for nano-structure fabrication with features ranging from nano- to micrometers in scale. The ability to evaporate materials with high precision, and thereby fabricate circuits and structures in situ, enables new kinds of experiments based on the interactions of a small number of atoms and eventually even single atoms.