Investigation of the Medieval Jeroným Mine Stability: Present Results from a Distributed Measurement Network

2011 ◽  
pp. 59-69 ◽  
Author(s):  
Jaromír Knejzlík ◽  
Zdeněk Kaláb ◽  
Markéta Lednická ◽  
Lubomír Staš
Keyword(s):  
Distributed Measurement ◽  
Mine Stability

scholarly journals Design and analysis of a fiber-optic sensing system for shape reconstruction of a minimally invasive surgical needle

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aizhan Issatayeva ◽  
Aida Amantayeva ◽  
Wilfried Blanc ◽  
Daniele Tosi ◽  
Carlo Molardi
Keyword(s):  
Performance Analysis ◽  
Minimally Invasive ◽  
Optical Fibers ◽  
Single Mode ◽  
Spectral Shift ◽  
Shape Reconstruction ◽  
Minimally Invasive Surgical ◽  
Working Principle ◽  
Doped Fibers ◽  
Distributed Measurement

AbstractThis paper presents the performance analysis of the system for real-time reconstruction of the shape of the rigid medical needle used for minimally invasive surgeries. The system is based on four optical fibers glued along the needle at 90 degrees from each other to measure distributed strain along the needle from four different sides. The distributed measurement is achieved by the interrogator which detects the light scattered from each section of the fiber connected to it and calculates the strain exposed to the fiber from the spectral shift of that backscattered light. This working principle has a limitation of discriminating only a single fiber because of the overlap of backscattering light from several fibers. In order to use four sensing fibers, the Scattering-Level Multiplexing (SLMux) methodology is applied. SLMux is based on fibers with different scattering levels: standard single-mode fibers (SMF) and MgO-nanoparticles doped fibers with a 35–40 dB higher scattering power. Doped fibers are used as sensing fibers and SMFs are used to spatially separate one sensing fiber from another by selecting appropriate lengths of SMFs. The system with four fibers allows obtaining two pairs of opposite fibers used to reconstruct the needle shape along two perpendicular axes. The performance analysis is conducted by moving the needle tip from 0 to 1 cm by 0.1 cm to four main directions (corresponding to the locations of fibers) and to four intermediate directions (between neighboring fibers). The system accuracy for small bending (0.1–0.5 cm) is 90$$\%$$ % and for large bending (0.6–1 cm) is approximately 92$$\%$$ % .

A Multiplexed Optical Fiber Sensor System For Distributed Measurement Of Structural Strains

1997 ◽  
Vol 503 ◽  
Author(s):  
F. Ansari ◽  
Z. Chen ◽  
Q. Li
Keyword(s):  
Optical Fiber ◽  
Optical Switch ◽  
Optical Fiber Sensor ◽  
Fiber Material ◽  
Smart Structure ◽  
Sensor System ◽  
Fiber Sensor ◽  
Fiber Sensors ◽  
Large Structures ◽  
Distributed Measurement

ABSTRACTStructurally integrated optical fiber sensors form the basis for smart structure technology. Over the past decade a variety of sensor configurations have been developed for measurement of strains and deformations in structures. Strains and deformations alter the refractive index and the geometry of the optical fiber material. These changes perturb the intensity, phase, and polarization of the light-wave propagating along the probing fiber. The optical perturbations are detected for the determination of strain. The research presented here describes the development of a new optical fiber sensor system for measurement of structural strains based on white light interferometry. An optical switch provides for multiplexing of strain signals from various locations in the structure. Redundant Bragg grating type fiber optic sensors as well as strain gauges were employed for comparison and verification of strain signals as measured by the new system. The system provides capability for distributed sensing of strains in large structures.

A lightweight distributed measurement method used to study illuminance estimation

Optik ◽  
2020 ◽  
Vol 223 ◽  
pp. 165590
Author(s):  
Luqiu Zhang ◽  
Yingming Gao ◽  
Zhanshuo Zhang ◽  
Nianyu Zou
Keyword(s):  
Measurement Method ◽  
Distributed Measurement
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