Distributed photonic instrumentation for smart grids

Photonic sensor networks possess the unique potential to provide the instrumentation infrastructure required in future smart grids by simultaneously addressing the issues of metrology and communications. In contrast to established optical CT/VT technology, recent developments at the University of Strathclyde in distributed point sensors for electrical and mechanical parameters demonstrate an enormous potential for realizing novel and effective monitoring and protection strategies for intelligent electrical networks and systems. In this paper, we review this technology and its capabilities, and describe recent work in power system monitoring and protection using hybrid electro-optical sensors. We show that wide-area visibility of multiple electrical and mechanical parameters from a single central location may be achieved using this technology, and discuss the implications for smart grid instrumentation

A new capacitive sensor for displacement measurement in a surface force apparatus

We present a new capacitive sensor for displacement measurement in a Surface Forces Apparatus (SFA) which allows dynamical measurements in the range of 0-100 Hz. This sensor measures the relative displacement between two macroscopic opaque surfaces over periods of time ranging from milliseconds to in principle an indefinite period, at a very low price and down to atomic resolution. It consists of a plane capacitor, a high frequency oscillator, and a high sensitivity frequency to voltage conversion. We use this sensor to study the nanorheological properties of dodecane confined between glass surfaces.Comment: 7 pages, 8 figure

High Accuracy Fuel Flowmeter, Phase 1

Technology related to aircraft fuel mass - flowmeters was reviewed to determine what flowmeter types could provide 0.25%-of-point accuracy over a 50 to one range in flowrates. Three types were selected and were further analyzed to determine what problem areas prevented them from meeting the high accuracy requirement, and what the further development needs were for each. A dual-turbine volumetric flowmeter with densi-viscometer and microprocessor compensation was selected for its relative simplicity and fast response time. An angular momentum type with a motor-driven, spring-restrained turbine and viscosity shroud was selected for its direct mass-flow output. This concept also employed a turbine for fast response and a microcomputer for accurate viscosity compensation. The third concept employed a vortex precession volumetric flowmeter and was selected for its unobtrusive design. Like the turbine flowmeter, it uses a densi-viscometer and microprocessor for density correction and accurate viscosity compensation

Evaluation of the sensor properties of the pH-static enzyme sensor

The pH-static enzyme sensor consists of a chemical sensor-actuator system covered with a thin enzyme-entrapping membrane. By the electrochemical generation of protons or hydroxyl ions, pH changes induced by the conversion of a substrate by the enzymatic reaction are compensated. The pH inside the membrane remains at a constant level and the control current is linearly related to the substrate concentration and independent of the buffer capacity of the sample. The sensitivity and linearity of the sensor response are evaluated. Depending on the enzyme load of the membrane, the operation of the sensor is either diffusion controlled or determined by the enzyme kinetics

Terahertz-based system for dehydration analysis of hydrogel contact lenses

The use of terahertz-based techniques has grown very fast since they are capable of performingevaluations at molecular level, being very suitable for the analysis of biological samples and bioma-terials such as those for contact lenses. These biomaterials are continuously evolving to enhancethe lens wearer’s comfort by improving their hydration state and surface wettability. Therefore, thisstudy examines a novel terahertz system for the assessment of the temporary in vitro dehydrationof hydrogel contact lenses, which provides a new index to assess their state of hydration. Severalconventional and silicone hydrogel contact lenses and lens care solutions were analysed. Traditionalmethods such as the gravimetric determination of water content and the measurement of the staticcontact angle were also carried out for the validation of the developed system. The dehydrationrate measurements of contact lenses obtained with the proposed system correlated with the valuesprovided by traditional methods. As a whole, conventional hydrogel contact lenses exhibited thelowest values for dehydration rate. The tests conducted on various solutions showed a correlationbetween the wetting action of the solution and the dehydration rate of the contact lens material.Peer ReviewedPostprint (published version

Conceptual design and analysis of a large antenna utilizing electrostatic membrane management

Conceptual designs and associated technologies for deployment 100 m class radiometer antennas were developed. An electrostatically suspended and controlled membrane mirror and the supporting structure are discussed. The integrated spacecraft including STS cargo bay stowage and development were analyzed. An antenna performance evaluation was performed as a measure of the quality of the membrane/spacecraft when used as a radiometer in the 1 GHz to 5 GHz region. Several related LSS structural dynamic models differing by their stiffness property (and therefore, lowest modal frequencies) are reported. Control system whose complexity varies inversely with increasing modal frequency regimes are also reported. Interactive computer-aided-design software is discussed

Index to nasa tech briefs, issue number 2

Annotated bibliography on technological innovations in NASA space program