36,606 research outputs found
Effects of the binder material on the mechanical properties of thick-film magnetostrictive materials
No full textThis paper presents research carried out at the University of Southampton into the development of a magnetostrictive thick-film material suitable for use with silicon micromachined devices. This form of magnetostrictive material has previously been deposited onto alumina substrates and this paper reports further work on migrating the technology onto silicon. The evaluation of two alternative glass frits for use as the binder within the thick film is reported. The correct choice of the binder material is important in a thick-film material because it is responsible for binding the active material within the thick film into a composite material and also adhering the film to the substrate. A series of tests have been applied to samples fabricated using various glass frits to assess their mechanical properties and suitability for the micro-actuator applications
Design and testing of a thick-film dual-modality sensor for composition measurements in heterogeneous mixtures
No full textThe current paper focuses on design and laboratory evaluation of a dual-modality sensor, developed for the needs of oil and gas extraction industry to measure the composition of heterogeneous mixtures in harsh conditions. The sensor combines ultrasonic and electrical measurement techniques, which are non-destructive, rapid and can potentially provide an on-line industrial measurement. Such a ‘dual-modality’ measurement could potentially be reliable in a wider range of process conditions. A distinct feature of the sensors presented here is their construction, which makes use of the thick-film technology, enabling the construction of multi-layered structures of both conductive and non-conductive layers, some of which may exhibit piezoelectric properties for ultrasonic measurement purposes. These are later fired on a ceramic substrate to provide rugged sensors, capable of working in aggressive industrial environments. Laboratory experiments to investigate the feasibility of the dual-modality sensors were conducted and some comparisons with the theoretical predictions are presented
Application of Analog Adaptive Filters for Dynamic Sensor Compensation
No full textThis paper investigates the application of analog adaptive techniques to the area of dynamic sensor compensation, of which there is little reported work in the literature. The case is illustrated by showing how the response of a load cell can be improved to speed up the process of measurement. The load cell is a sensor with an oscillatory output in which the measurand contributes to the response parameters. Thus, a compensation filter needs to track variation in measurand whereas a simple, fixed filter is only valid at one specific load value. To facilitate this investigation, computer models for the load cell and the adaptive compensation filter have been developed. To allow a practical implementation of the adaptive techniques, a novel piecewise linearization technique is proposed in order to vary a floating voltage-controlled resistor in a linear manner over a wide range. Simulation and practical results are presented, thus demonstrating the effectiveness of the proposed techniques
Appointment of Neil Armstrong as Member of the Chicago Regional Panel for the Selection of the 1977-78 White House Fellows, January 15, 1977
No full textGift of the Neil Armstrong Famil
Neil Burgess as Abigail Prue
No full textBlack and white photograph of Neil Burgess in drag as Abigail Prue from the play "The County Fair" featured in the columbia Theater booklet announcing upcoming productions for the 1895-1896 theater seaso
Use of a novel keypad biometric for enhanced user identity verification
No full textIn everyday life many actions are secured and/or authenticated by use of a secret personal identification number (PIN). This paper reports an improvement to the security afforded by a numeric PIN system through the addition of a covert biometric identification process. This biometric identification process is achieved through the use of a modified keypad incorporating force sensors within the individual keys, these sensors permit the dynamic measurement of applied force and key-press timings, providing an advantage over existing keystroke dynamic techniques which rely on time-domain information only. Details of the experimental setup used are given, and the results from initial tests are reported. In these tests an equal error rate of approximately 10% is obtained and a false acceptance rate of 15% with a corresponding false rejection rate of 0% has been shown
A study of the piezoresistive effect in thick-film resistors and its application to load transduction
No full textInexpensive, accurate, robust transducers have been sought for a long time, particularly for load sensing applications. Most attempts to produce such a device have suffered from significant trade offs, especially between cost and accuracy. The two main factors which contribute to the relatively high cost of loadcells are the cost of the primary sensor and the cost of machining the billet to reduce effects due to the eccentricity of loading. A new type of strain sensor based on the piezoresistive properties of thick-film resistors is described. Characterisation of the sensing element has revealed that the gauge factor is significantly higher than that of a metal foil strain gauge and the temperature coefficients are lower than those found for a semiconductor strain gauge. Results show how the gauge factor can be optimised by varying the production parameters. A loadcell based on thick-film strain gauges is also described. The design is such that the problems of eccentric loading are virtually eliminated. The technology also allows the associated electronics to be incorporated into the sensor housing.</p
Energy harvesting: an overview of techniques for use within the transport industry
No full textThis article introduces the various energy harvesting mechanisms that can be used to energize sensing systems and associated wireless communication channels. It outlines energy scavenging techniques, along with an assessment of useful materials for each mode of harvesting
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