Papers by Keyword: Instrumentation

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Authors: W. Li, B. Rodgers, D.J. Brookfield, John E. Mottershead, T.K. Hellen, R. Howard-Hildige, J. Jarvis, R. Lohr, A. Carlton, Maurice P. Whelan
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Authors: T. Holz, Reiner Dietsch, H. Mai, L. Brügemann
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Authors: P. Van der Sluis
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Authors: Trevor J. Holroyd
Abstract: The use of AE for testing the integrity of structures has a long history but its use for continuous monitoring of structures is not so well established. In a world of ageing infrastructure the need for methods of continuous monitoring is increasing so that the operation, maintenance and repair of structures can be more effectively managed. The extent to which AE will play a role in this obviously depends upon how effective it is in providing the wanted information in a timely manner to those who need it. However, other crucial aspects in its adoption will be the ease with which it can be used (e.g. specified, installed, interpreted) as well as its reliability and lifetime costs. With these considerations in mind, a multi-channel monitoring system has been developed called SIMPALTM. Throughout its development, field trials have been conducted with the aim of exploring the practical usefulness of a simpler kind of AE system. This paper provides an overview of the approach taken in developing the system and presents data gathered during proving trials and from its practical application to structures such as bridges.
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Authors: Michael F. Kuechel, Daniel M. Sykora
Abstract: Recent developments in next generation disc technology, cameras in mobile phones, zoom-lenses for small digital cameras and camcorders, digital SLRs, and television cameras have amplified the demand for affordable optical systems with outstanding image quality, a combination that can only be achieved using aspheric surfaces. The metrology of aspheric surfaces is a classical problem, but solutions so far have not fulfilled all demands for system cost, TACT (Total Average Cycle Time), minimized tooling, measurement uncertainty, spatial resolution, robustness in a production environment and many more. Zygo Corp. presents here a new method [1,2] for measurement of rotationally symmetrical aspheric surfaces using a new commercial system, which has the potential to fulfill these industry requirements. During measurement, the surface is scanned along its symmetry axis in a Fizeau cavity with a spherical reference surface. The coordinates x,y,z at the (moving) zone of normal incidence are derived from simultaneous phase-measurements at the apex and zone. Phase-shifting Fizeau interferometry and displacement interferometry are combined in the new commercial system to realize this new method. Aspheric departure from a best-fitsphere approaching 800 microns can be measured, and absolute measurement is possible with an absolutely calibrated transmission sphere. A custom parabolic artifact is measured with conventional null Fizeau interferometry and by the new commercial system. Data is reported for each technique along with a difference map achieved by fiducialized data subtract where 32.0 nm peak-to-valley (PV) and 3.6 nm R.M.S. are achieved.
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Authors: Hawsawi Abbas, Norikane Kanai
Abstract: The control engineering technology is a huge field of study. Above all, the instrumentation and control, likewise the plant automation has been classified as a special field of this technology. In this thesis we are introducing a practical learning material system that deals with instrumentation and plant control theory using LEGO Mindstorms and LEGO Bricks. There are different parts in the plant such as field instruments, controllers and analyzers, which are linked together to maintain a stable level of production. We are assuming that colleges and new employer will be able to use the developed system.
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Authors: Daniele Inaudi, Pascale Favez, Riccardo Belli, Daniele Posenato
Abstract: The dynamic monitoring of civil structures such as buildings and bridges is traditionally approached using acceleration and velocity sensors. When a monitoring program is designed to address concerns related to the level of strain in certain members, fatigue or displacements due to extreme loads, it is sometimes advantageous to measure those parameters directly, instead of deriving them from acceleration or velocity data. Inhomogeneous construction materials such as concrete, stone or masonry require the use of long-gauge sensors to measure strain, since local sensors can provide erroneous data due to local material changes. On the other hand, acceleration and tilt sensors are very useful to capture the global deformations and displacements. The development of long-gauge-length fiber optic sensors can be considered as a useful addition to the toolkit of those interested in the structural dynamics. The system can monitor structures over long periods of time at acquisition frequencies up to 10 kHz and with sub-microstrain resolution. The possibility of obtaining static and dynamic measurements from the same sensor is another advantage of this technology. For acceleration and tilt monitoring, MEMS sensors are now recognized as a powerful and low-cost alternative to more traditional sensor types. Fully-integrated sensors with 3-axis accelerometers and two-axis tiltmeters are now available in a compact packaging that also contain all data acquisition electronics and can be easily deployed in new or existing structures, connecting them directly to an Ethernet network. This contribution briefly introduces fiber optic and MEMS sensing technologies and will than illustrate their application to structural health monitoring through several examples, including the new I35W bridge in Minneapolis USA, the Ile d’Orléans suspension Bridge in Québec Canada and the shaking-table test of a full-scale masonry building reinforced with composite materials.
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Authors: Paulo Jose Rocha Albuquerque, David de Carvalho
Abstract: This paper presents the results of two load tests carried out in a continuous flight auger pile of 0.4 m in diameter and 12 m in length. The pile was instrumented in depth with strain gages in order to obtain the load capacity along the shaft and the tip. The load tests were carried out at the University of Campinas Experimental Site Test. The subsoil where the pile was installed is constituted by a first stratum of Silty Clay, which is porous and collapsible, of 6.5 m in thickness, followed by a stratum of residual soil of Clayey Silt up to 14 m depth. The first load test was the slow type, and a quick load test in the same pile after five days. From the results obtained with the use of instrumentation, the values for both lateral and tip load were determined in each one of test carried out in the pile studied. With these results and applying the Cambefort’s Law, it was could evaluate the evolution of the shaft friction and tip load in relation to the associated settlements, as well as the occurrence of residual load. The ultimate load obtained in the test was 960 kN and 810 kN for the first and second tests, respectively. The stress for the tip was 853 kPa and 655 kPa for the first and second tests, respectively.
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Authors: Kurt Walther, Alexander Frischbutter, Christian Scheffzük, M. Korobshenko, F. Levshanovski, A. Kirillov, N. Astachova, S. Mureshkevich
Abstract: This paper describes the modernized diffractometer EPSILON-MDS for strain measurements of geological samples by means of neutron diffraction with the time-of-flight method. The diffractometer is characterized by a long flight path in order to get a good spectral resolution and by a multi-detector system for efficient data acquisition.
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