Fiber-optic interferometric sensor of magnetic field for structural health monitoring

AbstractIn this paper we report on results of measurement of AC and DC magnetic field by fiber-optic interferometric sensor. Principle of operation is based on change of length of optical path cavity between the magnetostrictive wire and fiber-optic tip. Any change of the outside magnetic field causes elongation or contraction of the sensing wire. Using a fiber-optic sensing configuration based on single-mode 3×3 coupler and low-coherence interferometry we were able to read the instant separation between the wire and fiber ends with accuracy of about 50 nm. This separation corresponds with the intensity of the magnetic field in the range of 50 nT to 800 μT what is measured by using well calibrated magnetometer. The sensor is dedicated for on-line structural health monitoring of composite materials made of carbon reinforced epoxy matrix with integrated magnetic particles. Due to final purpose to be embedded in the structure, the sensor is designed to have small overall size of about 250 μm in outside diameter

ANKRD26 and Its Interacting Partners TRIO, GPS2, HMMR and DIPA Regulate Adipogenesis in 3T3-L1 Cells

Partial inactivation of the Ankyrin repeat domain 26 (Ankrd26) gene causes obesity and diabetes in mice and increases spontaneous and induced adipogenesis in mouse embryonic fibroblasts. However, it is not yet known how the Ankrd26 protein carries out its biological functions. We identified by yeast two-hybrid and immunoprecipitation assays the triple functional domain protein (TRIO), the G protein pathway suppressor 2 (GPS2), the delta-interacting protein A (DIPA) and the hyaluronan-mediated motility receptor (HMMR) as ANKRD26 interacting partners. Adipogenesis of 3T3-L1 cells was increased by selective down-regulation of Ankrd26, Trio, Gps2, Hmmr and Dipa. Furthermore, GPS2 and DIPA, which are normally located in the nucleus, were translocated to the cytoplasm, when the C-terminus of ANKRD26 was introduced into these cells. These findings provide biochemical evidence that ANKRD26, TRIO, GPS2 and HMMR are novel and important regulators of adipogenisis and identify new targets for the modulation of adipogenesis

Extensive recombination events and horizontal gene transfer shaped the Legionella pneumophila genomes

<p>Abstract</p> <p>Background</p> <p><it>Legionella pneumophila </it>is an intracellular pathogen of environmental protozoa. When humans inhale contaminated aerosols this bacterium may cause a severe pneumonia called Legionnaires' disease. Despite the abundance of dozens of <it>Legionella </it>species in aquatic reservoirs, the vast majority of human disease is caused by a single serogroup (Sg) of a single species, namely <it>L. pneumophila </it>Sg1. To get further insights into genome dynamics and evolution of Sg1 strains, we sequenced strains Lorraine and HL 0604 1035 (Sg1) and compared them to the available sequences of Sg1 strains Paris, Lens, Corby and Philadelphia, resulting in a comprehensive multigenome analysis.</p> <p>Results</p> <p>We show that <it>L. pneumophila </it>Sg1 has a highly conserved and syntenic core genome that comprises the many eukaryotic like proteins and a conserved repertoire of over 200 Dot/Icm type IV secreted substrates. However, recombination events and horizontal gene transfer are frequent. In particular the analyses of the distribution of nucleotide polymorphisms suggests that large chromosomal fragments of over 200 kbs are exchanged between <it>L. pneumophila </it>strains and contribute to the genome dynamics in the natural population. The many secretion systems present might be implicated in exchange of these fragments by conjugal transfer. Plasmids also play a role in genome diversification and are exchanged among strains and circulate between different <it>Legionella </it>species.</p> <p>Conclusion</p> <p>Horizontal gene transfer among bacteria and from eukaryotes to <it>L. pneumophila </it>as well as recombination between strains allows different clones to evolve into predominant disease clones and others to replace them subsequently within relatively short periods of time.</p

Fiber optic system for deflection and damage detection in morphing wing structures

Within the EC Clean Sky - Smart Fixed Wing Aircraft initiative concepts for actuating morphing wing structures are under development. In order for developing a complete integrated system including the actuation, the structure to be actuated and the closed loop control unit a hybrid deflection and damage monitoring system is required. The aim of the project "FOS3D" is to develop and validate a fiber optic sensing system based on low-coherence interferometry for simultaneous deflection and damage monitoring. The proposed system uses several distributed and multiplexed fiber optic Michelson interferometers to monitor the strain distribution over the actuated part. In addition the same sensor principle will be used to acquire and locate the acoustic emission signals originated from the onset and growth of defects like impact damages, cracks and delamination's. Within this paper the authors present the concept, analyses and first experimental results of the mentioned system

Simultaneous damage detection and deflection measurement of morphing wing structures by fiber optic sensing system

In this paper we present results of investigation of simultaneous damage detection and deflection measurement of morphing CFRP honeycomb structure by fiber optic sensing system developed in the frame of EU-FP7 project ÒFiber Optic System for Deflection and Damage Detection (FOS3D)î. The system is based on low- and high-coherence interferometry performed as Òall-in-fiberî sensing configuration. Raw signals have been on- and off-line processed by Òarctangî algorithm. Deflection data, expressed as phase angle change of the interferometer, have been simultaneously acquired with the reference data. A linear relationship between the fiber-optic sensing and reference technique is obtained. Slope of the linear fit line of 8 rad/mm denotes sensitivity of this sensor. Noise floor of about ±70µrad/√,Hz determines the lowest measurable wing deflection of about 6µm. Damage events have been simulated by pencil break and hammer impact with- and without damages over the CFRP honeycomb structure. Raw fiber-optic interference and reference acoustic emission sensor signals have been simultaneously acquired. Figure of merit is given as probability of detection (POD) and localization of simulated impact event. All events can be detected and located with a POD of more than 98% within the localization error of around 15 mm

Fine nanophased ZnO : Ru and ZnO : Pt powder synthesis through aerosols

Pt/Ru-doped ZnO nanophase particles were synthesized using ultrasonic spray pyrolysis. Particles were obtained through decomposition of zinc nitrate and newly developed Pt(IV) and Ru(III) complexes. The particle morphology, phase composition and chemical structure were revealed in accordance to various analysis methods (XRD, DSC, SEWEDS, TEM) and discussed in terms of precursor chemistry and process parameters. The shape of DSC curves, indicating two exothermic effects above 600 degrees C in both ZnO:Ru and ZnO:Pt, gave an indication of irreversible structural changes and high reactivity of as-prepared powders. The hexagonal wurtzite-type ZnO phase was revealed in both powdered samples. Small content of an intermediate Zn-5(NO3)(2)(OH)(8)(.)2H(2)O and cubic Zn2PtO4 phase were detected in the Pt-doped ZnO particles. Structural refinements, performed by Koalariet-XFit, suggest the composite internal particle structure composed of primary particles sized less than 100 nm. The estimated values for the unit cell parameters and Zn-O bond lengths imply noble metal ions incorporation into ZnO matrix interstitially, probably in octahedral interstitial environment. It has been shown that different particle growing morphologies (either spheroidally or pyramidally shaped) were influenced by the precursor chemistry, processing parameters and the presence of noble metal ions. Among the many parameters, attaining of the particle shape uniformity and homogeneous distribution of the noble metal cations in as-prepared particles are regarded as the most important factors for dominating microstructure evolution

Multiwavelength fiber-optic temperature sensor for cryogenic to high temperatures

The results of an investigation of an autoreferencing fiber-optic temperature sensor based on a CdTe single crystal are presented. A method for extending the working temperature range is proposed. A special sensor design permits measurements of low temperatures (lower than -50°C), as well as high temperatures of more than 400°C