226 research outputs found

    A Multimedia Manual On The World Wide Web For Telecommunications Equipment

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    An interactive multimedia educational manual on the Internet through the World Wide Web for commercial optical fiber telecommunications equipment is described. The Telecommunications Laboratory Manual is a vehicle for enhancing engineering education with realistic laboratory or virtual laboratory experience. The manual provides a brief system tutorial, operating instructions, on-line help, and multimedia experimental demonstrations. It incorporates block diagrams, photographic images, and hypertext links that are mouse clickable, allowing users to access documents or links describing components or processes in any order. An experimental section guides students through laboratory experiences, demonstrates selected equipment characteristics, and provides for direct instructor contact through e-mail. Other remote resources on the Internet are linked to create a global multimedia library. This paper describes the manual, its multimedia design, its use in the curriculum, and its further potential. © 1996 IEEE

    Work in Progress - Automated Discourse Interventions and Student Teaming

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    The ability to successfully work in teams is a crucial part of an engineer\u27s workplace success. Engineering education can be improved through a better understanding of how effective teamwork develops. A (patent pending) software tool that listens to team conversations and generates automatic interventions into team discourse can effectively mimic the actions of a skilled facilitator. Automated facilitation tools may help students improve their team skills by providing a simplified model for conversational interventions, which students can readily imitate. This paper describes this tool and presents preliminary findings from student reactions to the tool\u27s use

    Temperature Considerations in Solar Arrays

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    Temperature is an important consideration in the operation of photovoltaic (PV) arrays. In particular, daily and seasonal temperature variations are a limitation on the application of solar power to homes. At lower temperatures, PV systems produce more power. For higher temperatures, optimum operation requires modification of electrical load and removal of excess heat. Several technologies and approaches are available. To pursue this system optimization, PV cells were investigated at different temperatures. These investigations are compared with simulated theoretical results to draw more specific conclusions that can be applied to a solar house. A temperature reduction of 60‚ĀįC improved the power by up to twenty-seven percent with the current test cell. The simulations matched this conclusion and can be applied to the PV array used on a house. The University of Missouri-Rolla (UMR) and Rolla Technical Institute (RTI) jointly built a solar house for the 2002 National Solar Decathlon Competition. This house is the motivation and testbed for our research. The first application is to cool the cell; then compare the additional amount of power produced with the amount of power required to cool the cell. The feasibility of cooling the array is discussed. This paper first gives a description of the UMR/RTI solar house, a literature review, and overview. Temperature-dependence theory and experiments is given next. The third portion shows simulations including current-voltage curves and an analysis of load lines and temperature. The direct application of this research to the solar house and proposals for design considerations are summarized

    Fatigue Testing of a Composite Propeller Blade using Fiber-Optic Strain Sensors

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    The performance of surface-mounted extrinsic Fabry-Perot interferometric (EFPI) sensors during a seventeen-million-cycle, high-strain fatigue test is reported. Fiber-optic strain measurements did not degrade during the test. The sensors were applied to a composite propeller blade subject to a constant axial load and a cyclic bending load. Strain measurements were taken at four blade locations using two types of EFPI sensors and co-located electrical resistance strain gages. Static and dynamic strain measurements were taken daily during the 65 days of this standard propeller-blade test. All fiber-optic sensors survived the fatigue test while most of the resistive gages failed. The suitability of fiber-optic monitoring for fatigue testing and other high-cycle monitoring is demonstrated

    Work in Progress -- Instrumentation on a Truss Adapted for Pre-College Outreach

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    Engineering content is a valuable addition to pre-college instruction in science, technology, engineering, and mathematics (STEM) since it applies scientific concepts, illustrates scientific relevance and technology, and provides measurement opportunities. Also, complex systems and interactions can be shown. This work describes outreach resources using a seven-member instrumented truss apparatus. This aluminum bench-top model is scaled to support up to fifty pounds. Electrical resistance gauges are installed on several members for strain measurement. The resource set includes the truss apparatus, instrumentation, a PowerPoint presentation, and a background document. The pre-college objective is a set of demonstration resources for middle or high school classrooms. Effective outreach design is modeled by tailoring to accommodate curriculum standards, level-appropriate concept terms, and grade continuity. The resources were developed by students in an interdisciplinary college class on sensors and structures. The development activities involved testing the models and measurements and refining the construction. Selected resources were implemented and evaluated in a local middle school classroom. The interdisciplinary content includes structural, force analysis, sensing, and measurement components

    Regular smoking of male ancestors in adolescence and fat mass in young adult grandchildren and great-grandchildren

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    Background:¬†Previous studies using the Avon Longitudinal Study of Parents and Children (ALSPAC) have shown that if men commenced smoking prior to the onset of puberty their sons, their granddaughters and great-granddaughters were more likely to have excess fat (but not lean) mass during childhood, adolescence and early adulthood. In this study we assess associations between ancestral smoking during adolescence (ages 11‚Äď16 years) with fat and lean mass of subsequent generations at two ages. Methods: We analysed data on exposures of grandparents and great-grandparents collected by ALSPAC. The outcomes were the fat masses of their grandchildren and great-grandchildren measured at ages 17 and 24. Measures of lean mass were used as controls. Adjustment was made for 8‚Äď10 demographic factors using multiple regression. Results: We found associations between adolescent smoking of the paternal grandfathers and the adjusted fat mass of their grandchildren, but no associations with the grandchildren‚Äôs lean mass. Grandchildren at age 17 had an average excess fat mass of +1.65 [95% CI +0.04, +3.26] Kg, and at age 24 an average excess of +1.55 [95% CI -0.27, +3.38] Kg. Adolescent smoking by the maternal grandfather showed similar, but weaker, associations: at 17 an average excess fat mass of +1.02 Kg [95% CI -0.20, +2.25] Kg, and at 24 an average excess of +1.28 [95% CI -0.11, +2.66] Kg. There were no pronounced differences between the sexes of the children. For the great-grandparents there were few convincing results, although numbers were small. Conclusions: We have shown associations between grandfathers‚Äô smoking in adolescence and increased fat (but not lean) mass in their children. Confirmation of these associations is required, either in a further data set or by demonstrating the presence of supportive biomarkers

    Human transgenerational observations of regular smoking before puberty on fat mass in grandchildren and great-grandchildren

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    Previously, using data from the Avon Longitudinal Study of Parents and Children (ALSPAC) we showed that sons of fathers who had started smoking regularly before puberty (<‚ÄČ13¬†years) had increased fat mass during childhood, adolescence, and early adulthood. We now show that if the paternal grandfather had started smoking pre-puberty, compared with later in childhood (13‚Äď16¬†years), his granddaughters, but not grandsons, had evidence of excess fat mass at two ages: mean difference‚ÄČ+‚ÄČ3.54¬†kg; (P with 1-tailed test)‚ÄČ=‚ÄČ0.043 at 17¬†years, and‚ÄČ+‚ÄČ5.49¬†kg; (P(1)‚ÄČ=‚ÄČ0.016) at age 24. When fathers of maternal grandfathers had started smoking pre-puberty, their great-granddaughters, but not great-grandsons, had excess body fat:‚ÄČ+‚ÄČ5.35¬†kg (P(1)‚ÄČ=‚ÄČ0.050) at 17, and‚ÄČ+‚ÄČ6.10¬†kg (P(1)‚ÄČ=‚ÄČ0.053) at 24¬†years. Similar associations were not found with lean mass, in a sensitivity analysis. To determine whether these results were due to the later generations starting to smoke pre-puberty, further analyses omitted those in subsequent generations who had smoked regularly from‚ÄČ<‚ÄČ13¬†years. The results were similar. If these associations are confirmed in another dataset or using biomarkers, this will be one of the first human demonstrations of transgenerational effects of an environmental exposure across four generations

    Spatially Continuous Strain Monitoring using Distributed Fiber Optic Sensors Embedded in Carbon Fiber Composites

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    A distributed fiber optic strain sensor based on Rayleigh backscattering, embedded in a fiber-reinforced polymer composite, has been demonstrated. The optical frequency domain reflectometry technique is used to analyze the backscattered signal. The shift in the Rayleigh backscattered spectrum is observed to be linearly related to the change in strain of the composite material. The sensor (standard single-mode fiber) is embedded between the layers of the composite laminate. A series of tensile loads is applied to the laminate using an Instron testing machine, and the corresponding strain distribution of the laminate is measured. The results show a linear response indicating a seamless integration of the optical fiber in the composite material and a good correlation with the electrical-resistance strain gauge results. The sensor is also used to evaluate the strain response of a composite-laminate-based cantilever beam. Distributed strain measurements in a composite laminate are successfully obtained using an embedded fiber optic sensor
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