A Fiber-Optic Laser-Doppler Probe for Vibration Analysis of Rotating Machines

1980 ◽  
Vol 102 (3) ◽  
pp. 607-612 ◽  
Author(s):  
R. A. Cookson ◽  
P. Bandyopadhyay
Keyword(s):  
Fiber Optic ◽  
Scattered Light ◽  
Laser Doppler ◽  
Probe Laser ◽  
Fiber Optic Probe ◽  
Rotating System ◽  
Doppler Probe ◽  
Optic Probe ◽  
Similar Accuracy ◽  
Frequency Shifting

The problem of obtaining vibratory information from remote, rotating, components within a machine has been overcome by means of a laser-Doppler fiber-optic probe. Laser light is transmitted down the fiber-optic and scattered light is returned for analysis in the same way. The Twyman-Green mode of operation of the laser-Doppler system has been shown to have serious shortcomings for this type of work and a new mode has been produced, and used successfully, in conjunction with Bragg cells for frequency shifting. The use of a single set of Bragg cells to compensate for the average velocity of a rotating system, limits the allowable speed of rotation to about 1000 rpm. However, other techniques for frequency shifting are available. An experimental investigation is reported in which a rotating system, consisting of a disk carrying flat cantilever blades, was rotated at about 1000 rpm while one of the blades was excited at 163 Hz. The measured frequency of the vibrating blade was 162.8 Hz and similar accuracy was obtained for the amplitude measurements.

scholarly journals Effect of the Architecture of Fiber-Optic Probes Designed for Soluble Solid Content Prediction in Intact Sugar Beet Slices

Sensors ◽  
2019 ◽  
Vol 19 (13) ◽  
pp. 2995
Author(s):  
Ryad Bendoula ◽  
Arnaud Ducanchez ◽  
Ana Herrero-Langreo ◽  
Pablo Guerrero-Castro ◽  
Jean-Michel Roger ◽  
...  
Keyword(s):  
Sugar Beet ◽  
Fiber Optic ◽  
Scattered Light ◽  
Sugar Content ◽  
Probe Design ◽  
Fiber Optic Probe ◽  
Spectral Models ◽  
Technical Properties ◽  
Fiber Probes ◽  
Optic Probe

Sugar beet is the second biggest world contributor to sugar production and the only one grown in Europe. One of the main limitations for its competitiveness is the lack of effective tools for assessing sugar content in unprocessed sugar beet roots, especially in breeding programs. In this context, a dedicated near infrared (NIR) fiber-optic probe based approach is proposed. NIR technology is widely used for the estimation of sugar content in vegetable products, while optic fibers allow a wide choice of technical properties and configurations. The objective of this research was to study the best architecture through different technical choices for the estimation of sugar content in intact sugar beet roots. NIR spectral measurements were taken on unprocessed sugar beet samples using two types of geometries, single and multiple fiber-probes. Sugar content estimates were more accurate when using multiple fiber-probes (up to R2 = 0.93) due to a lesser disruption of light specular reflection. In turn, on this configuration, the best estimations were observed for the smallest distances between emitting and collecting fibers, reducing the proportion of multiply scattered light in the spectra. Error of prediction (RPD) values of 3.95, 3.27 and 3.09 were obtained for distances between emitting and collecting fibers of 0.6, 1.2 and 1.8 µm respectively. These high RPD values highlight the good predictions capacities of the multi-fiber probes. Finally, this study contributes to a better understanding of the effects of the technical properties of optical fiber-probes on the quality of spectral models. In addition, and beyond this specificity related to sugar beet, these findings could be extended to other turbid media for quantitative optical spectroscopy and eventually to validate considered fiber-optic probe design obtained in this experimental study.

Synthesis, performance and growth mechanism of silver nanoparticle coated SERS fiber probe

2019 ◽  
Vol 107 (3) ◽  
pp. 305
Author(s):  
Mengmei Geng ◽  
Yuting Long ◽  
Tongqing Liu ◽  
Zijuan Du ◽  
Hong Li ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Absorption Spectrum ◽  
Reaction Time ◽  
Growth Mechanism ◽  
Fiber Optic ◽  
Fiber Optic Probe ◽  
Visible Absorption ◽  
Fiber Probe ◽  
Surface Enhanced Raman ◽  
Optic Probe

Surface-enhanced Raman Scattering (SERS) fiber probe provides abundant interaction area between light and materials, permits detection within limited space and is especially useful for remote or in situ detection. A silver decorated SERS fiber optic probe was prepared by hydrothermal method. This method manages to accomplish the growth of silver nanoparticles and its adherence on fiber optic tip within one step, simplifying the synthetic procedure. The effects of reaction time on phase composition, surface plasmon resonance property and morphology were investigated by X-ray diffraction analysis (XRD), ultraviolet-visible absorption spectrum (UV-VIS absorption spectrum) and scanning electron microscope (SEM). The results showed that when reaction time is prolonged from 4–8 hours at 180 °C, crystals size and size distribution of silver nanoparticles increase. Furthermore, the morphology, crystal size and distribution density of silver nanoparticles evolve along with reaction time. A growth mechanism based on two factors, equilibrium between nucleation and growth, and the existence of PVP, is hypothesized. The SERS fiber probe can detect rhodamin 6G (R6G) at the concentration of 10−6 M. This SERS fiber probe exhibits promising potential in organic dye and pesticide residue detection.

Evaluation of Dry-Wet Transition in PEFC Under Load Changes Based on Laser Spectroscopy Using Fiber-Optic Probe

2019 ◽  
Vol 92 (8) ◽  
pp. 119-124
Author(s):  
Kosuke Nishida ◽  
Ryoga Nakauchi ◽  
Yuma Tabata ◽  
Toyofumi Umekawa ◽  
Masahiro Kawasaki
Keyword(s):  
Laser Spectroscopy ◽  
Fiber Optic ◽  
Fiber Optic Probe ◽  
Optic Probe

scholarly journals Longitudinal Raman Spectroscopic Observation of Skin Biochemical Changes due to Chemotherapeutic Treatment for Breast Cancer in Small Animal Model

2017 ◽  
Vol 2017 ◽  
pp. 1-9
Author(s):  
Myeongsu Seong ◽  
NoSoung Myoung ◽  
Songhyun Lee ◽  
Hyeryun Jeong ◽  
Sang-Youp Yim ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Animal Model ◽  
Raman Spectra ◽  
Fiber Optic ◽  
Animal Experiments ◽  
Small Animal ◽  
Fiber Optic Probe ◽  
Small Animal Model ◽  
Biochemical Compositions ◽  
Optic Probe

The cancer field effect (CFE) has been highlighted as one of indirect indications for tissue variations that are insensitive to conventional diagnostic techniques. In this research, we had a hypothesis that chemotherapy for breast cancer would affect skin biochemical compositions that would be reflected by Raman spectral changes. We used a fiber-optic probe-based Raman spectroscopy to perform preliminary animal experiments to validate the hypothesis. Firstly, we verified the probing depth of the fiber-optic probe (~800 μm) using a simple intravenous fat emulsion-filled phantom having a silicon wafer at the bottom inside a cuvette. Then, we obtained Raman spectra during breast cancer treatment by chemotherapy from a small animal model in longitudinal manner. Our results showed that the treatment causes variations of biochemical compositions in the skin. For further validation, the Raman spectra will have to be collected from more populations and spectra will need to be compared with immunohistochemistry of the breast tissue.

scholarly journals Autofluorescence and diffuse reflectance spectroscopy of oral epithelial tissue using a depth-sensitive fiber-optic probe

2008 ◽  
Vol 47 (6) ◽  
pp. 825 ◽  
Author(s):  
Richard A. Schwarz ◽  
Wen Gao ◽  
Dania Daye ◽  
Michelle D. Williams ◽  
Rebecca Richards-Kortum ◽  
...  
Keyword(s):  
Diffuse Reflectance ◽  
Fiber Optic ◽  
Diffuse Reflectance Spectroscopy ◽  
Reflectance Spectroscopy ◽  
Epithelial Tissue ◽  
Fiber Optic Probe ◽  
Optic Probe ◽  
Oral Epithelial
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