04/07/2010 - Koresh Dance Company.pdf

Simultaneous and multipoint assessment of vibration velocities is an important issue for the development of advanced noncontact vibrometers. In this article a novel fiber optic vibrometer is presented. The architecture of the sensor is based on a simple optical layout and it is characterized by multiple fiber optic interferometric sensors which are operated in the homodyne mode. Optical configuration and operation of the single-point version of the sensor, as well as the two-points measurement version, are described and typical measured signals with the operating range are shown. The sensor can easily be configured in order to perform a higher number of point measurements. Some details regarding signal acquisition and processing are also given and the ways in which Doppler demodulation is performed are discussed. Finally tests with sinusoidal target excitation in the range 0–1.8 kHz have been conducted

Strain Transfer in Surface-Bonded Optical Fiber Sensors

Fiber optic sensors represent one of the most promising technologies for the monitoring of various engineering structures. A major challenge in the field is to analyze and predict the strain transfer to the fiber core reliably. Many authors developed analytical models of a coated optical fiber, assuming null strain at the ends of the bonding length. However, this configuration only partially reflects real experimental setups in which the cable structure can be more complex and the strains do not drastically reduce to zero. In this study, a novel strain transfer model for surface-bonded sensing cables with multilayered structure was developed. The analytical model was validated both experimentally and numerically, considering two surface-mounted cable prototypes with three different bonding lengths and five load cases. The results demonstrated the capability of the model to predict the strain profile and, differently from the available strain transfer models, that the strain values at the extremities of the bonded fiber length are not null

Effects of thermal cycles on interfacial pressure in MV cable joints

The use of medium voltage cable joints is mandatory when dealing with power cable faults and the installation of new lines. However, such an accessory is among the top causes of faults among the grid. To this purpose, one of the quantities monitored to understand the causes of such faults is the interfacial pressure between the insulating layers of the cable joint. In this work, the interfacial pressure between Cross-linked polyethylene (XLPE) and silicon rubber has been evaluated when the cable joint experiences thermal cycles. From the results, the pressure variation caused by the thermal cycles is demonstrated. Such a phenomenon may be connected to the generation of voids and weak spots that accelerate cable joint ageing. Therefore, proper comments and conclusions are drawn

A Model-Assisted Probability of Detection Framework for Optical Fiber Sensors

Optical fiber sensors (OFSs) represent an efficient sensing solution in various structural health monitoring (SHM) applications. However, a well-defined methodology is still missing to quantify their damage detection performance, preventing their certification and full deployment in SHM. In a recent study, the authors proposed an experimental methodology to qualify distributed OFSs using the concept of probability of detection (POD). Nevertheless, POD curves require considerable testing, which is often not feasible. This study takes a step forward, presenting a model-assisted POD (MAPOD) approach for the first time applied to distributed OFSs (DOFSs). The new MAPOD framework applied to DOFSs is validated through previous experimental results, considering the mode I delamination monitoring of a double-cantilever beam (DCB) specimen under quasi-static loading conditions. The results show how strain transfer, loading conditions, human factors, interrogator resolution, and noise can alter the damage detection capabilities of DOFSs. This MAPOD approach represents a tool to study the effects of varying environmental and operational conditions on SHM systems based on DOFSs and for the design optimization of the monitoring system

Efficacy of hyaluronate injections in rotator cuff disorders: a level-I meta-analysis

Background: Rotator cuff disease is the most common cause of shoulder pain and weakness. Conservative treatment is the first choice of shoulder pain management. Viscosupplementation of hyaluronic acid (HA) seems to be effective for management of tendon disorders. The objective of this study was to evaluate the scientific evidence reported in literature according to HA shoulder injection in rotator cuff disorders treatment. Methods: An English-language systematic literature search was performed by two independent researchers; data sources included the following databases: MEDLINE, Embase, CINAHL, Google scholar web, Ovid database, Physiotherapy Evidence Database (PEDro), and the Cochrane Library. We performed a broad research for relevant study up to February 2017. Articles were included if they reported data on clinical and functional outcomes in patients who had undergone HA injection for management of rotator cuff pathology compared to placebo, corticosteroid injection and/or physical therapies. Methodological quality was assessed with the PEDro rating scale. The outcomes were improvement of symptoms (assessed by VAS scale) and shoulder function (assessed through DASH and ASES Score). Results: 5 RCTs studies (990 patients) were pooled in the Meta-analysis. The PEDro rating scale ranged from 2 to 8. Two studies compared HA injection with corticosteroid injections, patients were injected once a week for three weeks. Four studies compared HA injection with placebo injection, of which two used 3 weekly injections and two used 5 weekly injections. Significant difference was found in pain reduction between HA and placebo group at 26 weeks follow-up (MD= -0.51, 95% CI -0.96 to -0.07), p=0.02. Conclusion: HA injections might be a valuable safe alternative to other conservative methods for the treatment of rotator cuff disorders. Nowadays, few and low quality randomized controlled trials have been published. Therefore, to reach an overall conclusion about the effect of HA injection in rotator cuff we need more high quality studies. Level of evidence: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence. Study design: Meta-analys

Comparative mapping of the fragile histidine triad (FHIT) gene in cattle, river buffalo, sheep and goat by FISH and assignment to BTA22 by RH-mapping: a comparison with HSA3

Common fragile sites can be damaged by exposure to a variety of carcinogens. The fragile histidine triad (FHIT) gene, including the most active human chromosomal fragile site (FRA3B) at chromosome band HSA3p14.2,1 has been proposed as a tumour suppressor gene for a variety of tumours.2 The most common response to carcinogen exposure is deletions at the FHIT locus that alter the gene structure and function. In this study we assign the FHIT gene in cattle, river buffalo, sheep and goat chromosomes by comparative fluorescence in situ hybridization (FISH)-mapping. In addition, the assignment to BTA22 was confirmed by typing the marker across a bovine radiation hybrid (RH) panel

Dimensionality-Driven Metal-Insulator Transition in Spin-Orbit-Coupled SrIrO3

Upon reduction of the film thickness we observe a metal-insulator transition in epitaxially stabilized, spin-orbit-coupled SrIrO3 ultrathin films. By comparison of the experimental electronic dispersions with density functional theory at various levels of complexity we identify the leading microscopic mechanisms, i.e., a dimensionality-induced readjustment of octahedral rotations, magnetism, and electronic correlations. The astonishing resemblance of the band structure in the two-dimensional limit to that of bulk Sr2IrO4 opens new avenues to unconventional superconductivity by "clean" electron doping through electric field gating