Temperature compensated tactile sensing using MOSFET with P(VDF-TrFE)/BaTiO3 capacitor as extended gate

This work presents Poly(vinylidene fluoride – trifluoroethylene))/Barium Titanate (P(VDF-TrFE)-BT) nanocomposite based touch sensors tightly coupled with MOSFET devices in extended gate configuration. The P(VDF-TrFE)-BT nanocomposite exploits the distinct piezo and pyroelectric properties of P(VDF-TrFE) polymer matrix and BT fillers to suppress the temperature response when force and temperature are varied simultaneously. The reasons for this unique feature have been established through structural and electrical characterization of nanocomposite. The proposed touch sensor was tested over a wide range of force/pressure (0-4N)/(0-364 Pa) and temperature (26-70°C) with almost linear response. The sensitivity towards force/pressure and temperature sensor are 670 mV/N/7.36 mV/Pa and 15.34 mV/°C respectively. With this modified touch sensing capability, the proposed sensors will open new direction for tactile sensing in robotic applications

Characteristics of a 9mm triple-beam tuning fork resonant sensor

This paper describes the design and testing of the first miniaturised metallic triple-beam tuning fork resonant sensors for use in force, pressure and torque measurement applications. The new devices with 9mm length vibrating tines have resulted in over a 40% reduction in size when compared to previously tested resonators. The four fold increase in operating frequency to 26 kHz, with Q factors in air up to 4000, provides additional benefits for resolution, accuracy, range and overload capability. Measurement repeatability of at least 0.02% of span levels for torque transducers employing the sensors are quoted. Results of characterisation over the temperature range -30oC to +90oC are given

Quantum dynamics of a hydrogen-like atom in a time-dependent box: non-adiabatic regime

We consider a hydrogen atom confined in time-dependent trap created by a spherical impenetrable box with time-dependent radius. For such model we study the behavior of atomic electron under the (non-adiabatic) dynamical confinement caused by the rapidly moving wall of the box. The expectation values of the total and kinetic energy, average force, pressure and coordinate are analyzed as a function of time for linearly expanding, contracting and harmonically breathing boxes. It is shown that linearly extending box leads to de-excitation of the atom, while the rapidly contracting box causes the creation of very high pressure on the atom and transition of the atomic electron into the unbound state. In harmonically breathing box diffusive excitation of atomic electron may occur in analogy with that for atom in a microwave field

Wing Tip Vortex Drag

Optimization of L/D through minimizing induced drag through a detailed flow study together with force, pressure and vorticity measurements is considered. Flow visualization with neutral helium bubbles provides an excellent means of observing the effects of configuration changes

Designing a Decision Support System for Marine Reserves Management: An Economic Analysis for the Dutch North Sea

In this paper we discuss how a Decision Support System (DSS) for managing the marine environment can be set up. We use the Driving force-Pressure-State-Impact-Respond (DPSIR) framework to analyze which are the major driving forces impacting upon the marine environment in the North Sea. Moreover, a number of potential responses are identified. Furthermore, a preliminary and simplified optimization model has been set up and can be used in a DSS to decide on the best location of marine reserves for the protection of species. The model is based on a bio-economic metapopulation model that can be used to decide which parts of the sea should be opened for fisheries and which should be protected as marine reserve. It accounts for the dispersal of fish and considers both the economic returns from fisheries and the ecological value of marine biodiversity. A number of suggestions are given on how to extend and improve the DSS.Decision Support System, Marine Biodiversity Conservation, DPSIR Framework, Bioeconomic Modeling, North Sea

The merit of using silicon for the development of hearing aid microphones and intraocular pressure sensors

An important design rule for a hearing aid is the requirement of a large signal to noise ratio, which is mainly determined by that of the microphone and its preamplifier. It will be shown that in order to increase the signal to noise ratio it is favourable to integrate the preamplifier with the microphone, which implies that the microphone should be made of silicon, preferably with a single wafer technology. For the development of a tonometer for the measurement of intraocular pressure, the application of a silicon force sensor rationalizes that also the flattening of the eye globe is measured with a silicon applanation sensor, instead of by optical means which is the present practice. A sensor construction has been developed, which combines a force, pressure and applanation sensor, all made in silicon

Electro-osmotic flow through a rotating microchannel

Paper no. 306An analytical model is presented for electro-osmotic flow through a wide rectangular microchannel rotating about an axis perpendicular to its own. The flow is driven by a steady electric field applied along the channel axis, where the upper and lower walls are charged with uniform but possibly disparate zeta potentials. The aim is to understand the interaction between Coriolis force, pressure gradient, viscous force, and the Lorentz force.postprin

Aerodynamic validation of a SCAR design

Wind tunnel test of the McDonnell Douglas Supersonic Cruise Aircraft, designed for a cruise Mach number of 2.2, was conducted in the NASA Ames Unitary Plan Wind Tunnels. Extensive force, pressure, and flow visualization data were obtained over a Mach number range from 0.5 to 2.4. Comparisons between theory and measurements of both forces and pressure concentrate on the results obtained in the supersonic tunnel. Schlieren and tuft pictures are presented to help provide an understanding of the nonlinearities observed at off-design conditions

Instrumentation in wind tunnels

Requirements in designing instrumentation systems and measurements of various physical quantities in wind tunnels are surveyed. Emphasis is given to sensors used for measuring pressure, temperature, and angle, and the measurements of air turbulence and boundary layers. Instrumentation in wind tunnels require accuracy, fast response, diversity and operational simplicity. Measurements of force, pressure, attitude angle, free flow, pressure distribution, and temperature are illustrated by a table, and a block diagram. The LDV (laser Doppler velocimeter) method for measuring air turbulence and flow velocity and measurement of skin friction and flow fields using laser holograms are discussed. The future potential of these techniques is studied