scholarly journals Distributed Sensing Network Enabled by High-Scattering MgO-Doped Optical Fibers for 3D Temperature Monitoring of Thermal Ablation in Liver Phantom

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 828
Author(s):  
Aidana Beisenova ◽  
Aizhan Issatayeva ◽  
Zhannat Ashikbayeva ◽  
Madina Jelbuldina ◽  
Arman Aitkulov ◽  
...  
Keyword(s):  
High Resolution ◽  
Optical Fibers ◽  
Thermal Ablation ◽  
Single Point ◽  
Single Mode ◽  
Spatial Multiplexing ◽  
Temperature Monitoring ◽  
Fiber Optic Sensor ◽  
Potential Candidate ◽  
Distributed Fiber Optic Sensor

Thermal ablation is achieved by delivering heat directly to tissue through a minimally invasive applicator. The therapy requires a temperature control between 50–100 °C since the mortality of the tumor is directly connected with the thermal dosimetry. Existing temperature monitoring techniques have limitations such as single-point monitoring, require costly equipment, and expose patients to X-ray radiation. Therefore, it is important to explore an alternative sensing solution, which can accurately monitor temperature over the whole ablated region. The work aims to propose a distributed fiber optic sensor as a potential candidate for this application due to the small size, high resolution, bio-compatibility, and temperature sensitivity of the optical fibers. The working principle is based on spatial multiplexing of optical fibers to achieve 3D temperature monitoring. The multiplexing is achieved by high-scattering, nanoparticle-doped fibers as sensing fibers, which are spatially separated by lower-scattering level of single-mode fibers. The setup, consisting of twelve sensing fibers, monitors tissue of 16 mm × 16 mm × 25 mm in size exposed to a gold nanoparticle-mediated microwave ablation. The results provide real-time 3D thermal maps of the whole ablated region with a high resolution. The setup allows for identification of the asymmetry in the temperature distribution over the tissue and adjustment of the applicator to follow the allowed temperature limits.

scholarly journals Sensing, Actuation, and Control of the SmartX Prototype Morphing Wing in the Wind Tunnel

Actuators ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 107
Author(s):  
Nakash Nazeer ◽  
Xuerui Wang ◽  
Roger M. Groves
Keyword(s):  
Wind Tunnel ◽  
Optical Fibers ◽  
Fiber Optic ◽  
Experimental Testing ◽  
Single Mode ◽  
Fiber Optic Sensor ◽  
Sensor Data ◽  
Random Errors ◽  
Morphing Wing ◽  
Actuator Dynamics

This paper presents a study on trailing edge deflection estimation for the SmartX camber morphing wing demonstrator. This demonstrator integrates the technologies of smart sensing, smart actuation and smart controls using a six module distributed morphing concept. The morphing sequence is brought about by two actuators present at both ends of each of the morphing modules. The deflection estimation is carried out by interrogating optical fibers that are bonded on to the wing’s inner surface. A novel application is demonstrated using this method that utilizes the least amount of sensors for load monitoring purposes. The fiber optic sensor data is used to measure the deflections of the modules in the wind tunnel using a multi-modal fiber optic sensing approach and is compared to the deflections estimated by the actuators. Each module is probed by single-mode optical fibers that contain just four grating sensors and consider both bending and torsional deformations. The fiber optic method in this work combines the principles of hybrid interferometry and FBG spectral sensing. The analysis involves an initial calibration procedure outside the wind tunnel followed by experimental testing in the wind tunnel. This method is shown to experimentally achieve an accuracy of 2.8 mm deflection with an error of 9%. The error sources, including actuator dynamics, random errors, and nonlinear mechanical backlash, are identified and discussed.

Automated Fiber-Optic System for Monitoring the Stability of the Pit Quarry Mass and Dumps

2021 ◽  
pp. 19-26
Author(s):  
А.D. Меkhtiyev ◽  
◽  
E.G. Neshina ◽  
P.Sh. Madi ◽  
D.A. Gorokhov ◽  
...  
Keyword(s):  
Rock Mass ◽  
Optical Fiber ◽  
Optical Fibers ◽  
Fiber Optic ◽  
Light Wave ◽  
Single Mode ◽  
Fiber Optic Sensors ◽  
Fiber Optic Sensor ◽  
Laboratory Sample ◽  
Single Mode Optical Fiber

This article ls with the issues related to the development of a system for monitoring the deformation and displacement of the rock mass leading to the collapse of the quarry sides. Monitoring system uses point-to-point fiber-optic sensors. Fiber-optic sensors and control cables of the communication line are made based on the single mode optical fibers, which allows to measure with high accuracy the deformations and displacements of the rock mass at a distance of 30-50 km. To create fiber-optic pressure sensors, an optical fiber of the ITU-T G. 652.D standard is used. Laboratory sample is developed concerning the point fiber-optic sensor made based on the two-arm Mach-Zender interferometer using a single mode optical fiber for monitoring strain (displacements) with a change in the sensitivity and a reduced influence of temperature interference leading to zero drift. The article presents a mathematical apparatus for calculating the intensity of radiation of a light wave passing through an optical fiber with and without mechanical stress. A laboratory sample of single mode optical fibers based on the Mach-Zender interferometer showed a fairly high linearity and accuracy in the measurement and can be used to control the strain of the mass after appropriate refinement of its design. Mathematical expressions are also given for determining the intensity of the light wave when the distance between the fixing points of a single mode optical fiber changes depending on the change in the external temperature. A diagram for measuring strain using a point fiber-optic strain sensor is developed. Hardware and software package is developed, which can be used to perform a number of settings of measuring channels. The work is aimed at solving the production problems of the Kenzhem quarry of AK Altynalmas JSC.

scholarly journals Bend loss fiber optics design based on sinusoidal and ellipse configurations

2021 ◽  
Vol 51 (3) ◽  
Author(s):  
Noor Azie Azura Mohd Arif ◽  
Dilla Durhya Burhanuddin ◽  
Sahbudin Shaari ◽  
Abang Annuar Ehsan
Keyword(s):  
Fiber Optics ◽  
Optical Fibers ◽  
Optical Loss ◽  
Single Mode ◽  
Fiber Optic Sensor ◽  
Curvature Radius ◽  
Sensor Applications ◽  
Bending Loss ◽  
Bending Radius ◽  
Bending Sensor

Bending losses in optical fibers comprise one of the extrinsic attenuations that contribute to optical loss and they are essential for optical fiber bending sensor applications. This work investigated the optical loss in a standard single-mode step-index fiber optics due to fiber bending at 1550 nm wavelength. Variations in macro-bending loss with curvature radius and turn number have been measured. Curvature radius and turn number are examined for sinusoidal and elliptical shaped bending configurations. It has been found that the loss increases as the bending radius and number of turns increase. The result also showed that elliptical shaped bending configuration produced more loss in contrast to that of sinusoidal shaped at bending angles of 180° and 360°. The study on the macro-bending loss in terms of curvature radius and turn number for both elliptical and sinusoidal shaped bending configurations is beneficial for future fiber optic sensor applications.

scholarly journals Design of Fiber-Tip Refractive Index Sensor Based on Resonant Waveguide Grating with Enhanced Peak Intensity

2021 ◽  
Vol 11 (15) ◽  
pp. 6737
Author(s):  
Yicun Yao ◽  
Yanru Xie ◽  
Nan-Kuang Chen ◽  
Ivonne Pfalzgraf ◽  
Sergiy Suntsov ◽  
...  
Keyword(s):  
Refractive Index ◽  
Coupling Efficiency ◽  
High Sensitivity ◽  
Single Mode ◽  
Medical Diagnostics ◽  
Spatial Multiplexing ◽  
Fiber Optic Sensor ◽  
Resonant Peak ◽  
Refractive Index Sensor ◽  
Peak Intensity

Resonant waveguide gratings (RWG) are widely used as on-chip refractometers due to their relatively high sensitivity to ambient refractive index changes, their possibility of parallel high-throughput detection and their easy fabrication. In the last two decades, efforts have been made to integrate RWG sensors onto fiber facets, although practical application is still hindered by the limited resonant peak intensity caused by the low coupling efficiency between the reflected beam and the fiber mode. In this work, we propose a new compact RWG fiber-optic sensor with an additional Fabry-Pérot cavity, which is directly integrated onto the tip of a single-mode fiber. By introducing such a resonant structure, a strongly enhanced peak reflectance and improved figure of merit are achieved, while, at the same time, the grating size can be greatly reduced, thus allowing for spatial multiplexing of many sensors on a tip of a single multi-core fiber. This paves the way for the development of probe-like reflective fiber-tip RWG sensors, which are of great interest for multi-channel biochemical sensing and for real-time medical diagnostics.

scholarly journals Distributed Strain Measurement along a Concrete Beam via Stimulated Brillouin Scattering in Optical Fibers

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Romeo Bernini ◽  
Aldo Minardo ◽  
Stefano Ciaramella ◽  
Vincenzo Minutolo ◽  
Luigi Zeni
Keyword(s):  
Optical Fibers ◽  
Strain Measurement ◽  
Concrete Beam ◽  
Fiber Optic ◽  
Brillouin Scattering ◽  
Fiber Optic Sensor ◽  
Optic Sensor ◽  
Tension And Compression ◽  
Distributed Fiber Optic Sensor ◽  
Term Performance

The structural strain measurement of tension and compression in a 4 m long concrete beam was demonstrated with a distributed fiber-optic sensor portable system based on Brillouin scattering. Strain measurements provided by the fiber-optic sensor permitted to detect the formation of a crack in the beam resulting from the external applied load. The sensor system is valuable for structural monitoring applications, enabling the long-term performance and health of structures to be efficiently monitored.

Design Considerations in Reduced-Diameter Single-Mode Optical Fibers

2002 ◽  
Author(s):  
Wilson K. Chiu ◽  
Gregory H. Ames ◽  
Marilyn J. Berliner
Keyword(s):  
Optical Fibers ◽  
Single Mode ◽  
Design Considerations

scholarly journals Matchup Characteristics of Sea Surface Salinity Using a High-Resolution Ocean Model

2021 ◽  
Vol 13 (15) ◽  
pp. 2995
Author(s):  
Frederick M. Bingham ◽  
Severine Fournier ◽  
Susannah Brodnitz ◽  
Karly Ulfsax ◽  
Hong Zhang
Keyword(s):  
High Resolution ◽  
Time Window ◽  
Single Point ◽  
Ocean Model ◽  
Sea Surface ◽  
Sea Surface Salinity ◽  
Surface Salinity ◽  
Argo Floats ◽  
Statistical Measures ◽  
Salinity Difference

Sea surface salinity (SSS) satellite measurements are validated using in situ observations usually made by surfacing Argo floats. Validation statistics are computed using matched values of SSS from satellites and floats. This study explores how the matchup process is done using a high-resolution numerical ocean model, the MITgcm. One year of model output is sampled as if the Aquarius and Soil Moisture Active Passive (SMAP) satellites flew over it and Argo floats popped up into it. Statistical measures of mismatch between satellite and float are computed, RMS difference (RMSD) and bias. The bias is small, less than 0.002 in absolute value, but negative with float values being greater than satellites. RMSD is computed using an “all salinity difference” method that averages level 2 satellite observations within a given time and space window for comparison with Argo floats. RMSD values range from 0.08 to 0.18 depending on the space–time window and the satellite. This range gives an estimate of the representation error inherent in comparing single point Argo floats to area-average satellite values. The study has implications for future SSS satellite missions and the need to specify how errors are computed to gauge the total accuracy of retrieved SSS values.

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