989 resultados para 1995_12180638 Optics-20


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Although a wide range of techniques exist for slope monitoring, the task of monitoring slopes is sometimes complicated by the extensive nature and unpredictability of slope movements. The Brillouin optical time-domain reflectometer (BOTDR) is a distributed optical fiber strain measurement technology utilising Brillouin scattering. This method measures continuous strain along a standard optical fibre over a distance up to 10 km and hence has potential to detect deformations and diagnose problems along large sections of slopes and embankments. This paper reports the demonstration of BOTDR method for monitoring surface ground movements of clay cuttings and embankments along London's ring M25 motorway. A field trial investigating varying methods of onsite fibre optic installations was conducted. The surrounding ground was artificially moved by excavating a 3 m deep trench perpendicular to the instrumented sections. Results obtained from onsite installations after slope movement demonstrate a half-pipe covered fibre optic installed on wide (200mm) Tensar ™SS20 geogrid gives the most consistent recorded strain change profile. Initial conclusions suggest this method best represents induced ground motion at the surface and hence is recommended for implementation in future sitework. Copyright ASCE 2008.

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Statistics and data overviews from the eight member countries. Southeast Asian Fisheries Development Center(SEAFDEC)overview and activities since 2010. Statistics working group recommendations and workplan

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The goals of the workshop were to: conduct an interactive workshop for characterizing Indian coastal ecosystems; verification of the ecosystem characterisation report for the East coast of India; and development of ecosystem characterisation for the west coast of India based on ecological/biophysical systems.

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Participants were exposed to concepts and information about Ecosystem Approach to Fisheries Management (EAFM) using a structured, participatory method of delivery. The learning strategy involved specifically designed exercises, using real examples, to consolidate learning. Daily monitoring and reviews were conducted together with pre-and post-course assessment.

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This workshop was held at the National Bureau of Fish Genetic Resources and followed on from the Indian mackerel Working group meeting in Colombo (28-29 May, 2012). Activities included; DNA extraction; PCR (Polymerase Chain Reaction) for microsatellites; genotyping microsatellites; data analysis; emerging technologies; and an action plan

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This course, co-hosted by South East Asian Fisheries Development Centre (SEAFDEC), was a refined version of the pilot course held in Malaysia in June 2013. Participants were exposed to concepts and information about Ecosystem Approach to Fisheries Management (EAFM) using a structured, participatory method of delivery. The learning strategy involved specifically designed exercises, using real examples, to consolidate learning. Daily monitoring and reviews were conducted together with pre-and post-course assessment.

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Participants consisted of 25 middle and junior level personnel from BOBLME countries. Modules included: Integrated Coastal Management (ICM) concept and principles; ICM development and implementation; indicators of good practice; and action planning.

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20 Gb/s QPSK transmission over 100 m of OM3 fibre using an EOM VCSEL under QPSK modulation is reported. Bit-error-ratio measurements are carried out to express the quality of the transmission scheme. © 2011 OSA.

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It is shown that reflective liquid crystal on silicon (LCOS) spatial light modulator (SLM) based interconnects or fiber switches that use defocus to reduce crosstalk can be evaluated and optimized using a fractional Fourier transform if certain optical symmetry conditions are met. Theoretically the maximum allowable linear hologram phase error compared to a Fourier switch is increased by a factor of six before the target crosstalk for telecom applications of -40 dB is exceeded. A Gerchberg-Saxton algorithm incorporating a fractional Fourier transform modified for use with a reflective LCOS SLM is used to optimize multi-casting holograms in a prototype telecom switch. Experiments are in close agreement to predicted performance. © 2012 Optical Society of America.

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A scalable multi-channel optical regenerative bus architecture based on the use of polymer waveguides is presented for the first time. The architecture offers high-speed interconnection between electrical cards allowing regenerative bus extension with multiple segments and therefore connection of an arbitrary number of cards onto the bus. In a proof-ofprinciple demonstration, a 4-channel 3-card polymeric bus module is designed and fabricated on standard FR4 substrates. Low insertion losses (≤ -15 dB) and low crosstalk values (< -30 dB) are achieved for the fabricated samples while better than ± 6 μm -1 dB alignment tolerances are obtained. 10 Gb/s data communication with a bit-error-rate (BER) lower than 10-12 is demonstrated for the first time between card interfaces on two different bus modules using a prototype 3R regenerator. © 2012 Optical Society of America.