1,410 research outputs found
Materials science and the sensor revolution
For the past decade, we have been investigating strategies to develop
ways to provide chemical sensing platforms capable of long-term
deployment in remote locations1-3. This key objective has been driven by
the emergence of ubiquitous digital communications and the associated
potential for widely deployed wireless sensor networks (WSNs).
Understandably, in these early days of WSNs, deployments have been
based on very reliable sensors, such as thermistors, accelerometers, flow
meters, photodetectors, and digital cameras. Biosensors and chemical
sensors (bio/chemo-sensors) are largely missing from this rapidly
developing field, despite the obvious value offered by an ability to measure
molecular targets at multiple locations in real-time. Interestingly, while
this paper is focused on the issues with respect to wide area sensing of
the environment, the core challenge is essentially the same for long-term
implantable bio/chemo-sensors4, i.e.; how to maintain the integrity of the
analytical method at a remote, inaccessible location
Nanoenergetic Materials for MEMS: A Review
New energetic materials (EMs) are the key to great advances in microscale energy-demanding systems as actuation part, igniter, propulsion unit, and power. Nanoscale EMs (nEMs)particularly offer the promise of much higher energy densities, faster rate of energy release, greater stability, and more security sensitivity to unwanted initiation). nEMs could therefore give response to microenergetics challenges. This paper provides a comprehensive review of current research activities in nEMs for microenergetics application. While thermodynamic calculations of flame temperature and reaction enthalpies are tools to choose desirable EMs, they are not sufficient for the choice of good material for microscale application where thermal losses are very penalizing. A strategy to select nEM is therefore proposed based on an analysis of the material diffusivity and heat of reaction. Finally, after a description of the different nEMs synthesis approaches, some guidelines for future investigations are provided
Adaptive locomotion of artificial microswimmers
Bacteria can exploit mechanics to display remarkable plasticity in response
to locally changing physical and chemical conditions. Compliant structures play
a striking role in their taxis behavior, specifically for navigation inside
complex and structured environments. Bioinspired mechanisms with rationally
designed architectures capable of large, nonlinear deformation present
opportunities for introducing autonomy into engineered small-scale devices.
This work analyzes the effect of hydrodynamic forces and rheology of local
surroundings on swimming at low Reynolds number, identifies the challenges and
benefits of utilizing elastohydrodynamic coupling in locomotion, and further
develops a suite of machinery for building untethered microrobots with
self-regulated mobility. We demonstrate that coupling the structural and
magnetic properties of artificial microswimmers with the dynamic properties of
the fluid leads to adaptive locomotion in the absence of on-board sensors
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