Design of a Fiber Optic Pressure Transducer

1977 ◽  
Vol 99 (1) ◽  
pp. 274-279 ◽  
Author(s):  
R. H. Pahler ◽  
A. S. Roberts
Keyword(s):  
Light Intensity ◽  
Light Source ◽  
Pressure Transducer ◽  
Fiber Optic ◽  
Light Guide ◽  
Circular Array ◽  
Analytic Procedure ◽  
Reflected Light ◽  
Cylindrical Metal ◽  
Selection Of

Performance characteristics of a fiber optic pressure transducer are presented and discussed. The transducer consists of a cylindrical metal housing with a specular reflecting aluminum diaphragm at the distal end and a circular array of fiber optic light guide bundles at the proximal end. The center bundle is connected to a light source with the surrounding bundles carrying reflected light to a photodetector. A change in pressure on the diaphragm produces a differential change in light intensity. An analytic procedure guides the selection of an optimal configuration in order to obtain maximum transducer response.

scholarly journals Rediscovery of Darkfieid Dispersion Staining while Building a Universal Student Microscope

2003 ◽  
Vol 11 (1) ◽  
pp. 24-28
Author(s):  
Theodore M. Clarke
Keyword(s):  
Light Source ◽  
Light Microscope ◽  
Fiber Optic ◽  
Light Guide ◽  
Polarized Light ◽  
Cover Glass ◽  
Artistic Value ◽  
Aperture Diaphragm ◽  
Reflected Light

My first universal student microscope, shown in Figure 1, began life as a Monolux microscope from the 1960rs. Its development into a universal student microscope began when my wife wanted a polarized light microscope with the ability to photograph microscopic crystals under a cover glass for their artistic value. My background as a metallurgist was with the reflected light metallurgical microscope, I have also designed and built vertical illuminators for brightfield illumination of complete metal log raphic specimens using a fiber optic light guide end as the light source with lens configurations giving an imaged field diaphragm and an illumination aperture diaphragm imaged in the aperture of the macro lens.

A New Liquid-Crystal-Based Fiber-Optic Temperature Sensor

1989 ◽  
Vol 43 (8) ◽  
pp. 1333-1336 ◽  
Author(s):  
Chu Zhu ◽  
Gary M. Hieftje
Keyword(s):  
Liquid Crystal ◽  
Standard Deviation ◽  
Light Intensity ◽  
Temperature Sensor ◽  
Fiber Optic ◽  
Temperature Range ◽  
Reflected Light ◽  
Relative Standard ◽  
Fiber Optic Temperature Sensor ◽  
Fiber Optic Temperature

A new fiber-optic temperature sensor has been developed, based upon selective reflection from a cholesteric liquid crystal. The change of reflected-light intensity can be 40 times larger than background over a temperature range of only 0.4°C. For the demonstrated system, the temperature at which maximum reflection occurred was at 14.578°C, with a standard deviation of 0.026°C. The relative standard deviation of the peak reflected-light intensity was 7.1%. The dependence of the magnitude of reflection and that of peak temperature on the heating rate were studied. The response time of the present sensor is about 2 s, but it could be shortened with slight design modifications. Each sensor of the new type should be applicable to temperature sensing or control over a temperature range of about 1°C.

Phagocytosis by Kupffer cells predominates in pericentral regions of the liver lobule

1990 ◽  
Vol 259 (5) ◽  
pp. G814-G821 ◽  
Author(s):  
J. M. te Koppele ◽  
R. G. Thurman
Keyword(s):  
Kupffer Cells ◽  
Fiber Optic ◽  
Light Guide ◽  
Carbon Uptake ◽  
Liver Lobule ◽  
Particle Uptake ◽  
Carbon Particles ◽  
Reflected Light ◽  
Large Fiber ◽  
Light Guides

These studies were designed to determine whether particle phagocytosis could be monitored from the surface of the perfused liver. To achieve this goal, decreases in reflected light were measured during phagocytosis of colloidal carbon particles. Livers were illuminated with 623-nm light via a relatively large fiber-optic light guide (tip diam 2 mm), and reflected light was monitored continuously. A decrease in reflected light was observed when carbon was infused that was proportional to the influent carbon concentration. Initial changes in reflected light were linearly related to rates of carbon uptake by Kupffer cells. Subsequently, rates of carbon uptake were determined from changes in reflected light in periportal and pericentral regions of the liver lobule with miniature fiber-optic light guides. In perfusions in the anterograde direction, rates of carbon uptake were approximately 80% higher in pericentral than periportal regions of the liver lobule. This pattern was reversed when livers were perfused in the retrograde direction. Thus particle phagocytosis predominates in downstream regions of the liver lobule. Because decreasing the pH of the influent perfusate increased carbon uptake, the pH gradient over the liver lobule may be involved in the regulation of particle uptake at the sublobular level.

Inter-Method Reliability of Pulse Volume Related Measures Derived Using Finger-Photoplethysmography

2018 ◽  
Vol 32 (4) ◽  
pp. 182-190 ◽  
Author(s):  
Kenta Matsumura ◽  
Koichi Shimizu ◽  
Peter Rolfe ◽  
Masanori Kakimoto ◽  
Takehiro Yamakoshi
Keyword(s):  
Light Intensity ◽  
Adverse Effects ◽  
Light Source ◽  
Direct Current ◽  
Resting State ◽  
Current Component ◽  
Psychophysiological Measures ◽  
Pulse Volume ◽  
Optical Paths ◽  
Sensor Positions

Abstract. Pulse volume (PV) and its related measures, such as modified normalized pulse volume (mNPV), direct-current component (DC), and pulse rate (PR), derived from the finger-photoplethysmogram (FPPG), are useful psychophysiological measures. Although considerable uncertainties exist in finger-photoplethysmography, little is known about the extent of the adverse effects on the measures. In this study, we therefore examined the inter-method reliability of each index across sensor positions and light intensities, which are major disturbance factors of FPPG. From the tips of the index fingers of 12 participants in a resting state, three simultaneous FPPGs having overlapping optical paths were recorded, with their light intensity being changed in three steps. The analysis revealed that the minimum values of three coefficients of Cronbach’s α for ln PV, ln mNPV, ln DC, and PR across positions were .948, .850, .922, and 1.000, respectively, and that those across intensities were .774, .985, .485, and .998, respectively. These findings suggest that ln mNPV and PR can be used for psychophysiological studies irrespective of minor differences in sensor attachment positions and light source intensity, whereas and ln DC can also be used for such studies but under the condition of light intensity being fixed.

Design of light source for ultra-high precision fiber optic gyroscope

2021 ◽  
Author(s):  
Xin Chen ◽  
Miao Yan ◽  
Jie Yu ◽  
Ruoxiang Tang
Keyword(s):  
Light Source ◽  
High Precision ◽  
Fiber Optic ◽  
Fiber Optic Gyroscope

A Reversible Change of Reflected Light Intensity between Molten and Solidified Ge–Sb–Te Alloy

2007 ◽  
Vol 46 (No. 36) ◽  
pp. L868-L870 ◽  
Author(s):  
Masashi Kuwahara ◽  
Rie Endo ◽  
Toshio Fukaya ◽  
Takayuki Shima ◽  
Yasuhiko Iwanabe ◽  
...  
Keyword(s):  
Light Intensity ◽  
Reversible Change ◽  
Reflected Light

scholarly journals Cyanobacteria use micro-optics to sense light direction

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Nils Schuergers ◽  
Tchern Lenn ◽  
Ronald Kampmann ◽  
Markus V Meissner ◽  
Tiago Esteves ◽  
...  
Keyword(s):  
Light Intensity ◽  
Light Source ◽  
Type Iv Pili ◽  
Small Cells ◽  
Unicellular Cyanobacterium ◽  
Light Sensing ◽  
High Resolution Image ◽  
Type Iv ◽  
Micro Optics ◽  
Synechocystis Sp

Bacterial phototaxis was first recognized over a century ago, but the method by which such small cells can sense the direction of illumination has remained puzzling. The unicellular cyanobacterium Synechocystis sp. PCC 6803 moves with Type IV pili and measures light intensity and color with a range of photoreceptors. Here, we show that individual Synechocystis cells do not respond to a spatiotemporal gradient in light intensity, but rather they directly and accurately sense the position of a light source. We show that directional light sensing is possible because Synechocystis cells act as spherical microlenses, allowing the cell to see a light source and move towards it. A high-resolution image of the light source is focused on the edge of the cell opposite to the source, triggering movement away from the focused spot. Spherical cyanobacteria are probably the world’s smallest and oldest example of a camera eye.

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