scholarly journals Fabrication of a Fluorophore-Doped Cylindrical Waveguide Structure Using Elastomers for Visual Detection of Stress

Fibers ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 37 ◽  
Author(s):  
Hirose ◽  
Fukuda ◽  
Sassa ◽  
Ishibashi ◽  
Ochiai ◽  
...  
Keyword(s):  
Energy Flow ◽  
Fiber Optic ◽  
Color Change ◽  
Emission Spectra ◽  
Elastic Response ◽  
Sensor Performance ◽  
The Core ◽  
Elastic Waveguide ◽  
Detection Of Stress ◽  
Human Eyes

A fiber-optic strain sensor that can show strain via color change and which can be viewed using human eyes has demand in the civil engineering field for alerting purposes. A previous sensor was fabricated using PMMA (Poly(methyl methacrylate)), which had the exceeding hardness to exhibit satisfactory sensor performance. In this research, an elastomer-based fiber-optic structure was fabricated to enhance the elastic response of such sensors and to enlarge the waveguide cross section. Various organic fluorophores were added to the core and cladding regions of the elastic waveguide to induce energy flow from the core to the cladding when stress is applied to the waveguide. Elastomer pairs suitable for the core and cladding were selected from among several candidate materials having high transparency. A method of dispersing fluorophores to each host elastomer and constructing an excellent core–cladding interface using the selected materials was proposed. To investigate the time-dependent changes in the fluorescence of the doped elastomer waveguide, the absorption and emission spectra were monitored after the host elastomers were cured.

scholarly journals Performance Analysis of Scattering-Level Multiplexing (SLMux) in Distributed Fiber-Optic Backscatter Reflectometry Physical Sensors

Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2595 ◽  
Author(s):  
Daniele Tosi ◽  
Carlo Molardi ◽  
Wilfried Blanc ◽  
Tiago Paixão ◽  
Paulo Antunes ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Rayleigh Scattering ◽  
Fiber Optic ◽  
Single Fiber ◽  
Distributed Sensor ◽  
The Core ◽  
Physical Sensors ◽  
Core Section ◽  
Boundary Limits ◽  
Multiple Fibers

Optical backscatter reflectometry (OBR) is a method for the interrogation of Rayleigh scattering occurring in each section of an optical fiber, resulting in a single-fiber-distributed sensor with sub-millimeter spatial resolution. The use of high-scattering fibers, doped with MgO-based nanoparticles in the core section, provides a scattering increase which can overcome 40 dB. Using a configuration-labeled Scattering-Level Multiplexing (SLMux), we can arrange a network of high-scattering fibers to perform a simultaneous scan of multiple fiber sections, therefore extending the OBR method from a single fiber to multiple fibers. In this work, we analyze the performance and boundary limits of SLMux, drawing the limits of detection of N-channel SLMux, and evaluating the performance of scattering-enhancement methods in optical fibers.

scholarly journals The Global Energy Landscape and Materials Innovation

MRS Bulletin ◽  
2008 ◽  
Vol 33 (4) ◽  
pp. 264-288 ◽  
Author(s):  
V.S. Arunachalam ◽  
E.L. Fleischer
Keyword(s):  
Renewable Resources ◽  
Energy Security ◽  
Energy Flow ◽  
Energy Landscape ◽  
Energy Resources ◽  
Energy Sources ◽  
Energy Availability ◽  
Additional Energy ◽  
The Core ◽  
The World

AbstractAvailability of affordable energy has enabled spectacular growth of industrialization and human development in all parts of the world. With growth now accelerating in developing countries, demands on energy sources and infrastructure are being stretched to new limits. Additional energy issues include the push for renewable resources with reduced greenhouse gas emissions and energy security affected by the uneven distribution of energy resources around the globe. Together, these issues present a field of opportunity for innovations to address energy challenges throughout the world and all along the energy flow. These energy challenges form the backdrop for this special expanded issue of MRS Bulletin on Harnessing Materials for Energy. This article introduces the global landscape of materials issues associated with energy. It examines the complex web of energy availability, production, storage, transmission, distribution, use, and efficiency. It focuses on the materials challenges that lie at the core of these areas and discusses how revolutionary concepts can address them. Cross-cutting topics are introduced and interrelationships between topics explored. Article topics are set in the context of the grand energy challenges that face the world into the middle of this century.

CORE-HOLE EFFECT IN THE Ce L3 X-RAY ABSORPTION SPECTRA OF CeO2 AND CeFe2: NEW EXAMINATION BY USING RESONANT X-RAY EMISSION SPECTROSCOPY

2013 ◽  
Vol 27 (16) ◽  
pp. 1330012 ◽  
Author(s):  
A. KOTANI
Keyword(s):  
Absorption Spectra ◽  
Ground State ◽  
Theoretical Calculations ◽  
Emission Spectra ◽  
Core Hole ◽  
Final State ◽  
X Ray ◽  
The Core ◽  
X Ray Absorption ◽  
Hole Effect

We consider two different resonant X-ray emission spectra for Ce compounds: Ce 3d to 2p X-ray emission (denoted by 3d-RXES) and valence to 2p X-ray emission (v-RXES), both of which follow the Ce 2p to 5d resonant excitation. We propose that the comparison of the 3d- and v-RXES spectra is a new powerful method of directly detecting the core-hole effect in the final state of Ce L 3 X-ray absorption spectra (XAS). We applied this method to recent experimental RXES spectra for CeO 2 and CeFe 2, and showed unambiguously that the core-hole effect should be essential in the XAS of both materials. This result is confirmed by theoretical calculations, which reproduce well the experimental RXES and XAS spectra. We conclude that the ground state of CeO 2 is in the mixed state of 4f0 and [Formula: see text] configurations, where [Formula: see text] is a ligand hole, instead of a pure 4f0 configuration which was proposed recently by first-principles energy band calculations. Also, we conclude that the double peaks observed in L 3 XAS of CeFe 2 are caused by the 4f0 and 4f1 configurations, which are mixed in the ground state but separated in energy by the large core-hole potential in the final state of XAS.

Tunable Athermal Multi-FBG Package Using a Bending Bimetal Structure

2000 ◽  
Vol 124 (1) ◽  
pp. 54-59 ◽  
Author(s):  
Samuel I-En Lin
Keyword(s):  
Temperature Compensation ◽  
Fiber Optic ◽  
Compensation Mechanism ◽  
Central Wavelength ◽  
Experimental Procedure ◽  
The Core ◽  
System A ◽  
Stable Temperature ◽  
Fiber Optic Communication ◽  
Optic Communication

The Fiber Bragg Gratings (FBGs) written by ultraviolet light into the core of an optical fiber have developed into a critical component for many applications in the fiber-optic communication system. A stable temperature compensation mechanism is essential to the successful usage of FBG-based devices. In this paper, the bimetal-based temperature-compensating package with tunable mechanism was developed. Such a tunable mechanism serves as prestress and post-tuning mechanisms of fixture in order to obtain a predetermined central wavelength. With the aid of developed experimental procedure, this compact and easily manufactured package can achieve temperature coefficient of 8.3×10−4 nm/°C in the temperature range from −40°C to 80°C. The same package can also be used for multi-FBG applications.

scholarly journals Passive Fiber Optic Evanescent Wave Sensor for the Measurement of Refractive Index at Various Temperatures using a Tunable Light Source

2019 ◽  
Vol 8 (6S) ◽  
pp. 681-691
Keyword(s):  
Refractive Index ◽  
Light Source ◽  
Evanescent Wave ◽  
Fiber Optic ◽  
Fiber Optic Sensor ◽  
Depth Of Penetration ◽  
The Core ◽  
Passive Fiber ◽  
Highly Sensitive ◽  
Shaped Glass

The study of refractive index of liquids over a range of 10oC to 60oC shows very interesting results to design and develop a highly sensitive passive fiber optic sensor based on a U-shaped glass probe. The depth of penetration of light that escaping from the core of the fiber into the cladding plays a crucial role in the development of a highly sensitive fiber optic evanescent wave sensor. The depth of penetration of an optical fiber striped off its cladding is directly related to the wavelength of the light, the index of refraction of the surrounding medium, the angle of incidence of light, the bending radius and thickness of the U-shaped probe. In the design of the sensor a U-shaped glass probe is used to replace the core of the fiber in the region of sensing, the diameter of which is same as that of the cores of a pair of insensitive fibers which in-turn connected to a tunable light source and an optical detector. The sensor is highly reliable, robust and easy to configure using multimode PCS fibers and the source operating at the wavelengths of 630nm, 660nm, 820nm and 850nm.

scholarly journals Ab Externo Imaging of Human Episcleral Vessels Using Fiberoptic Confocal Laser Endomicroscopy

2019 ◽  
Author(s):  
Ken Y. Lin ◽  
Sameh Mosaed
Keyword(s):  
Minimally Invasive ◽  
Real Time ◽  
Fiber Optic ◽  
Ex Vivo ◽  
Confocal Laser Endomicroscopy ◽  
Confocal Laser ◽  
Flow Variation ◽  
Regional Flow ◽  
Tissue Manipulation ◽  
Human Eyes

Purpose: There is a growing interest in targeting minimally invasive surgery devices to the aqueous outflow system to optimize treatment outcomes. However, methods to visualize functioning, large-caliber aqueous and episcleral veins in-vivo are lacking. This pilot study establishes an ex-vivo system to evaluate the use of a confocal laser microendoscope to noninvasively image episcleral vessels and quantify regional flow variation along the limbal circumference. Methods: A fiber-optic confocal laser endomicroscopy (CLE) system with lateral and axial resolution of 3.5 μm and 15 μm, respectively, was used on three porcine and four human eyes. Diluted fluorescein (0.04%) was injected into eyes kept under constant infusion. The microprobe was applied to the sclera 1 mm behind the limbus to acquire real-time video. Image acquisition was performed at 15-degree intervals along the limbal circumference to quantify regional flow variation in human eyes. Results: Vascular structures were visualized in whole human eyes without processing. Schlemm’s canal was visualized only after a scleral flap was created. Fluorescent signal intensity and vessel diameter variation were observed along the limbal circumference, with the inferior quadrant having a statistically higher fluorescein signal compared to the other quadrants in human eyes (P < 0.05). Conclusion: This study demonstrates for the first time that the fiber-optic CLE platform can visualize the episcleral vasculature with high resolution ex-vivo with minimal tissue manipulation. Intravascular signal intensities and vessel diameters were acquired in real-time; such information can help select target areas for minimally invasive glaucoma surgery (MIGS) to achieve greater intraocular pressure reduction.

A fiber-optic probe and FT-NIR for onsite quality analysis of olive oils

NIR news ◽  
2018 ◽  
Vol 29 (4) ◽  
pp. 4-8 ◽  
Author(s):  
José A Adame-Siles ◽  
Francisco Sánchez-Müller ◽  
Francisco Maroto-Molina ◽  
Cecilia Riccioli ◽  
Ana Garrido-Varo ◽  
...  
Keyword(s):  
Near Infrared ◽  
Fiber Optic ◽  
Fiber Optic Sensor ◽  
Quality Analysis ◽  
Fiber Optic Probe ◽  
Sensor Performance ◽  
Olive Oils ◽  
Decision Making Processes ◽  
Enhance Efficiency ◽  
Optic Probe

Compliance checks at reception of olive oil in bulk before unloading is an essential step for packing plants to meet quality standards and ensure traceability. Nevertheless, classic procedures based on the withdrawal of samples followed by at-line analysis need to be improved. Near-infrared spectroscopy features can make it an ideal technology to enhance efficiency and decision-making processes. This article presents a new approach whose main pillar is the automated use of a fiber-optic sensor to sample and analyse olive oils in bulk, directly in the tank before the downloading at the reception point. Moreover, a preliminary assessment of the sensor performance is also reported.

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