Dominique Leduc

Bio: Dominique Leduc is an academic researcher from University of Nantes. The author has contributed to research in topics: Fiber Bragg grating & Optical fiber. The author has an hindex of 12, co-authored 50 publications receiving 374 citations.

Distributed Fiber Optics Sensing and Coda Wave Interferometry Techniques for Damage Monitoring in Concrete Structures

Abstract: The assessment of Coda Wave Interferometry (CWI) and Distributed Fiber Optics Sensing (DFOS) techniques for the detection of damages in a laboratory size reinforced concrete beam is presented in this paper. The sensitivity of these two novel techniques to micro cracks is discussed and compared to standard traditional sensors. Moreover, the capacity of a DFOS technique to localize cracks and quantify crack openings is also assessed. The results show that the implementation of CWI and DFOS techniques allow the detection of early subtle changes in reinforced concrete structures until crack formation. With their ability to quantify the crack opening, following early detection and localization, DFOS techniques can achieve more effective monitoring of reinforced concrete structures. Contrary to discrete sensors, CWI and DFOS techniques cover larger areas and thus provide more efficient infrastructures asset management and maintenance operations throughout the lifetime of the structure.

Determination of refractive index, thickness, and the optical losses of thin films from prism-film coupling measurements

Abstract: We present a method of analysis of prism-film coupler spectroscopy based on the use of transfer matrix and genetic algorithm, which allows the simultaneous determination of refractive index, thickness, and optical losses of the measured layer.

Concrete Crack Monitoring Using a Novel Strain Transfer Model for Distributed Fiber Optics Sensors.

Abstract: In this paper, we study the strain transfer mechanism between a host material and an optical fiber. A new analytical model handling imperfect bonding between layers is proposed. A general expression of the crack-induced strain transfer from fractured concrete material to optical fiber is established in the case of a multilayer system. This new strain transfer model is examined through performing wedge splitting tests on concrete specimens instrumented with embedded and surface-mounted fiber optic cables. The experimental results showed the validity of the crack-induced strain expression fitted to the distributed strains measured using an Optical Backscattering Reflectometry (OBR) system. As a result, precise estimations of the crack openings next to the optical cable location were achieved, as well as the monitoring of the optical cable response through following the strain lag parameter.

Properties Of Concrete

Abstract: Thank you for downloading properties of concrete. As you may know, people have look hundreds times for their chosen readings like this properties of concrete, but end up in malicious downloads. Rather than reading a good book with a cup of coffee in the afternoon, instead they juggled with some malicious virus inside their computer. properties of concrete is available in our digital library an online access to it is set as public so you can download it instantly. Our digital library hosts in multiple locations, allowing you to get the most less latency time to download any of our books like this one. Merely said, the properties of concrete is universally compatible with any devices to read.

Progress in optics

Abstract: Have you ever felt that the very title, Progress in Optics, conjured an image in your mind? Don’t you see a row of handsomely printed books, bearing the editorial stamp of one of the most brilliant members of the optics community, and chronicling the field of optics since the invention of the laser? If so, you are certain to move the bookend to make room for Volume 16, the latest of this series. It contains seven chapters on widely diverging topics, written by well-known authorities in their fields. These are: 1) Laser Selective Photophysics and Photochemistry by V. S. Letokhov, 2) Recent Advances in Phase Profiles (sic) Generation by J. J. Clair and C. I. Abitbol, 3 ) Computer-Generated Holograms: Techniques and Applications by W.-H. Lee, 4) Speckle Interferometry by A. E. Ennos, 5 ) Deformation Invariant, Space-Variant Optical Pattern Recognition by D. Casasent and D. Psaltis, 6) Light Emission from High-Current Surface-Spark Discharges by R. E. Beverly, and 7) Semiclassical Radiation Theory within a QuantumMechanical Framework by I. R. Senitzkt. The breadth of topic matter spanned by these chapters makes it impossible, for this reviewer at least, to pass judgement on the comprehensiveness, relevance, and completeness of every chapter. With an editorial board as prominent as that of Progress in Optics, however, it seems hardly likely that such comments should be necessary. It should certainly be possible to take the authority of each author as credible. The only remaining judgment to be made on these chapters is their readability. In short, what are they like to read? The first sentence of the first chapter greets the eye with an obvious typographical error: “The creation of coherent laser light source, that have tunable radiation, opened the . . . .” Two pages later we find: “When two types of atoms or molecules of different isotopic composition ( A and B ) have even one spectral line that does not overlap with others, it is pos-

Polymer optical fiber sensors—a review

Abstract: Polymer optical fibers (POFs) have significant advantages for many sensing applications, including high elastic strain limits, high fracture toughness, high flexibility in bending, high sensitivity to strain and potential negative thermo-optic coefficients. The recent emergence of single-mode POFs has enabled high precision, large deformation optical fiber sensors. This article describes recent advances in both multi-mode and single-mode POF based strain and temperature sensors. The mechanical and optical properties of POFs relevant to strain and temperature applications are first summarized. POFs considered include multi-mode POFs, solid core single-mode POFs and microstructured single-mode POFs. Practical methods for applying POF sensors, including connecting and embedding sensors in structural materials, are also described. Recent demonstrations of multi-mode POF sensors in structural applications based on new interrogation methods, including backscattering and time-of-flight measurements, are outlined. The phase‐displacement relation of a single-mode POF undergoing large deformation is presented to build a fundamental understanding of the response of single-mode POF sensors. Finally, this article highlights recent single-mode POF based sensors based on polymer fiber Bragg gratings and microstructured POFs. (Some figures in this article are in colour only in the electronic version)

Deep brain stimulation between 1947 and 1987: the untold story

Abstract: Deep brain stimulation (DBS) is the most rapidly expanding field in neurosurgery. Movement disorders are well-established indications for DBS, and a number of other neurological and psychiatric indications are currently being investigated. Numerous contemporary opinions, reviews, and viewpoints on DBS fail to provide a comprehensive account of how this method came into being. Misconceptions in the narrative history of DBS conveyed by the wealth of literature published over the last 2 decades can be summarized as follows: Deep brain stimulation was invented in 1987. The utility of high-frequency stimulation was also discovered in 1987. Lesional surgery preceded DBS. Deep brain stimulation was first used in the treatment of movement disorders and was subsequently used in the treatment of psychiatric and behavioral disorders. Reports of nonmotor effects of subthalamic nucleus DBS prompted its use in psychiatric illness. Early surgical interventions for psychiatric illness failed to adopt a multidisciplinary approach; neurosurgeons often worked "in isolation" from other medical specialists. The involvement of neuro-ethicists and multidisciplinary teams are novel standards introduced in the modern practice of DBS for mental illness that are essential in avoiding the unethical behavior of bygone eras. In this paper, the authors examined each of these messages in the light of literature published since 1947 and formed the following conclusions. Chronic stimulation of subcortical structures was first used in the early 1950s, very soon after the introduction of human stereotaxy. Studies and debate on the stimulation frequency most likely to achieve desirable results and avoid side effects date back to the early days of DBS; several authors advocated the use of "high" frequency, although the exact frequency was not always specified. Ablative surgery and electrical stimulation developed in parallel, practically since the introduction of human stereotactic surgery. The first applications of both ablative surgery and chronic subcortical stimulation were in psychiatry, not in movement disorders. The renaissance of DBS in surgical treatment of psychiatric illness in 1999 had little to do with nonmotor effects of subthalamic nucleus DBS but involved high-frequency stimulation of the very same brain targets previously used in ablative surgery. Pioneers in functional neurosurgery mostly worked in multidisciplinary groups, including when treating psychiatric illness; those "acting in isolation" were not neurosurgeons. Ethical concerns have indeed been addressed in the past, by neurosurgeons and others. Some of the questionable behavior in surgery for psychiatric illness, including the bygone era of DBS, was at the hands of nonneurosurgeons. These practices have been deemed as "dubious and precarious by yesterday's standards."