11,918 research outputs found

    Flush mounting of thin film sensors

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    Flush mounting of a sensor on a surface is provided by first forming a recessed area on the surface. Next, an adhesive bonding mixture is introduced into the recessed area. The adhesive bonding mixture is chosen to provide thermal expansion matching with the surface surrounding the recessed area. A strip of high performance polymeric tape is provided, with the sensor attached to the underside thereof, and the tape is positioned over the recessed area so that it acts as a carrier of the sensor. A shim having flexibility so that it will conform to the surface surrounding the recessed area is placed over the tape, and a vacuum pad is placed over the shim. The area above the surface is then evacuated while holding the sensor flush with the surface during curing of the adhesive bonding mixture. After such curing, the pad, shim, and tape are removed from the sensor, electrical connections for the sensor are provided, after which the remaining space in the recessed area is filled with a polymeric foam

    Practical approaches for application of resistance type strain gages on high temperature composites

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    Four major areas of interest with respect to utilizing strain gages on carbon/carbon (with SiC surfaces) and titanium matrix composites are addressed. Strain gage and adhesive combinations on carbon/carbon (C/C) at temperatures from minus 190 C to to 540 C, half-bridge gaging for reducing apparent strain on C/C using Poisson's ratio and bending configurations, a review of the 'field installation' techniques developed for gaging a C/C hypersonic generic elevon, and results of initial strain gaging efforts on titanium matrix composites are discussed. Current research in developing techniques for increasing the maximum temperature for strain gages on carbon/carbon are reviewed

    Circumferential pressure probe

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    A probe for measuring circumferential pressure inside a body cavity is disclosed. In the preferred embodiment, a urodynamic pressure measurement probe for evaluating human urinary sphincter function is disclosed. Along the length of the probe are disposed a multiplicity of deformable wall sensors which typically comprise support tube sections with flexible side wall areas. These are arranged along the length of the probe in two areas, one just proximal to the tip for the sensing of fluid pressure inside the bladder, and five in the sensing section which is positioned within the urethra at the point at which the urinary sphincter constricts to control the flow of urine. The remainder of the length of the probe comprises multiple rigid support tube sections interspersed with flexible support tube sections in the form of bellows to provide flexibility

    Chimeric Realities

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    This essay examines the urban experience in postmodern cities and mediated reality. Modernity brought a change in perception that altered the experience of the city. This shift was registered through cinema which disrupted the fixity of classical space and provided an aesthetic reception similar to the gaze the flaneur. With the transition into postmodernism came the idea of the Heterotopia, a city that is capable of juxtaposing multiple temporalities and spaces that are themselves incompatible. The postmodern city developed with the exponential growth of mass communication and consumption immersing us in mediated reality. My projective works make use of collage techniques to produce images that match the way in which we perceive, interact, and navigate mediated reality. My sequence makes use of cinematic qualities to immerse viewers in the imaginary spaces portrayed. The postmodern city is experienced as a territory in which we simultaneously inhabit a multiplicity of spaces, both digital and physical. These intertwined realities give the postmodern city a phantasmagoric character, one of undefined spatiality

    A Competition Module for a Small Business Management Class

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    In this study, the author evaluates a condition that exists among many college students, the lack of either willingness or ability to compete with one another in order to achieve objectives. The review of literature indicates that students\u27 inability to compete was predicated by a trend, in recent decades, among educators to focus on students\u27 self image and self esteem rather than on one\u27s accomplishments relative to one\u27s peers. This educational focus has yielded a preoccupation with a concern that no student should ever experience losing. However, with this trend, something was lost, students\u27 capacity to realistically assess their skills and their ability to compete. Research shows that a student\u27s inability to compete can severely compromise the student\u27s potential for success after graduation. A module was developed for inclusion in a Small Business Management class curriculum. The intent of the curriculum is to reintroduce and encourage the concept of competition, and to demonstrate the need to compete in order to be successful in a commercial marketplace after graduation

    Crossflow vorticity sensor

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    A crossflow vorticity sensor for the detection of crossflow vorticity characteristics is described. The sensor is comprised of crossflow sensors which are noninvasively adhered to a swept wing laminar surface either singularly, in multi-element strips, in polar patterns, or in orthogonal patterns. These crossflow sensors are comprised of hot-film sensor elements which operate as a constant temperature anemometer circuit to detect heat transfer rate changes. Accordingly, crossflow vorticity characteristics are determined via cross-correlation. In addition, the crossflow sensors have a thickness which does not exceed a maximum value h in order to avoid contamination of downstream crossflow sensors

    Nondestructive testing techniques used in analysis of honeycomb structure bond strength

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    DOT /Driver-Displacement Oriented Transducer/, applicable to both lap shear type application and honeycomb sandwich structures, measures the displacement of the honeycomb composite face sheet. It incorporates an electromagnetic driver and a displacement measuring system into a single unit to provide noncontact bond strength measurements

    The Angular Resolution of Space-Based Gravitational Wave Detectors

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    Proposed space-based gravitational wave antennas involve satellites arrayed either in an equilateral triangle around the earth in the ecliptic plane (the ecliptic-plane option) or in an equilateral triangle orbiting the sun in such a way that the plane of the triangle is tilted at 60 degrees relative to the ecliptic (the precessing-plane option). In this paper, we explore the angular resolution of these two classes of detectors for two kinds of sources (essentially monochromatic compact binaries and coalescing massive-black-hole binaries) using time-domain expressions for the gravitational waveform that are accurate to 4/2 PN order. Our results display an interesting effect not previously reported in the literature, and underline the importance of including the higher-order PN terms in the waveform when predicting the angular resolution of ecliptic-plane detector arrays.Comment: 13 pages, 6 figures, submitted to Phys Rev D. The current version corrects an error in our original paper and adds some clarifying language. The error also required correction of the graphs now shown in Figures 3 through

    Recommended Strain Gage Application Procedures for Various Langley Research Center Balances and Test Articles

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    The NASA Langley Research Center uses more than 10000 strain gages per year in supporting its various research programs. The character of the testing at LaRC is such that the types of strain gage installations, the materials they are applied to, and the test environments encountered, require many varied approaches for installing strain gages. These installations must be accomplished in the most technically discerning and appropriate manner. This technical memorandum is offered as an assisting guide in helping the strain gage user to determine the appropriate approach for a given strain gage application requirement. Specifically, this document offers detailed recommendations for strain gaging the following: LaRC-Designed balances, LARC custom transducers, certain composite materials and alloys, high-temperature test articles, and selected non-typical or unique materials or test conditions
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