scholarly journals A model of degree of scattering polarization for oil spilling

2020 ◽  
Vol 50 (3) ◽  
Author(s):  
Xiao Wang ◽  
Jiang Xu ◽  
Weixian Qian ◽  
Jingyi Ouyang
Keyword(s):  
Optical Sensors ◽  
Stokes Parameter ◽  
Polarization Measurement ◽  
Fresnel Reflection ◽  
Oil Film ◽  
Scattering Rate ◽  
Reflected Light ◽  
Polarization Characteristics ◽  
Fresnel Formula ◽  
Spilled Oil

Oil slicks often show uncertain surface roughness and Fresnel reflection parameters. Consequently, differentiating oil spilled on the seawater in these areas using optical sensors is a challenge. Therefore, the optical mechanism of the oil film has been studied by the Maxwell equation. It is found that the polarization characteristics of the oil slicks can help us to overcome this problem. According to the Fresnel formula, the scattering coefficient and scattering rate of the homogeneous oil film have been deduced, and the phase difference of the scattering electromagnetic wave has also been calculated to verify the accuracy of the model. The parameter, a degree of scattering polarization, has been derived to identify the oil slicks on the sea wave. It depends on accurately knowing the Stokes parameter for the reflected light, and varies with the refractive index of the surface layer and viewing angles. The actual spilled oil has been measured by this model, and the oil film can be accurately identified at various angles. These preliminary results suggest that the potential of multi-angle polarization measurement of ocean surface needs further researches.

Modelling Light Transmission in a Fiber-Optical Reflection System

2004 ◽  
Vol 9 (1) ◽  
pp. 55-63
Author(s):  
V. Kleiza
Keyword(s):  
Optical Sensors ◽  
Light Transmission ◽  
External Cavity ◽  
Linear Displacement ◽  
Fiber System ◽  
Light Emitting ◽  
Optical Media ◽  
Reflected Light ◽  
Fiber Optical ◽  
Fiber Optical Sensors

Light transmission in the reflection fiber system, located in external optical media, has been investigated for application as sensors. The system was simulated by different models, including external cavity parameters such as the distance between light emitting and receiving fibers and mirror positioning distance. The sensitivity to a linear displacement of the sensors was studied as a function of the distance between the tips of the light emitting fiber and the center of the pair reflected light collecting fibers, by positioning a mirror. Physical fundamentals and operating principles of the advanced fiber optical sensors were revealed.

scholarly journals Spindle Error Motion Measurement Using Concentric Circle Grating and Phase Modulation Interferometers

2013 ◽  
Vol 7 (5) ◽  
pp. 506-513 ◽  
Author(s):  
Muhummad Madden ◽  
◽  
Masato Aketagawa ◽  
Shuhei Uesugi ◽  
Takuya Kumagai ◽  
...  
Keyword(s):  
Optical Sensors ◽  
Phase Modulation ◽  
Interference Fringe ◽  
Measurement Instrument ◽  
Concentric Circle ◽  
Order Diffraction ◽  
Fine Pitch ◽  
Reflected Light ◽  
Interpolation Technique ◽  
Error Motion

In the conventional methods of measuring radial, axial, and angular motions of a spindle concurrently, complicated reference artifacts with relative large volume, e.g., two balls linked to a cylinder, are required. A simple and small artifact is favorable from the viewpoint of accurate measurement. This paper describes a concurrent measurement of radial, axial, and angular spindle motions using concentric circle grating and phase modulation interferometers. In the measurement, concentric circle grating with fine pitch is installed on top of the spindle of interest. The grating is a reference artifact in the method. Three optical sensors are fixed over the concentric circle grating, to observe its proper positions. The optical sensor consists of a frequency modulated laser diode as a light source as well as two interferometers. One interferometer observes an interference fringe between reflected light from a fixedmirror and 0-th order diffraction light from the grating to measure the axial motion. Another interferometer observes an interference fringe between ± 2nd order diffraction lights from the grating tomeasure the radialmotion. Using three optical sensors, three axial displacements, and three radial displacements of the proper observed position of the grating can be measured. From these measured displacements, radial, axial, and angular motions of the spindle can be calculated concurrently. In this paper, a measurement instrument, a novel fringe interpolation technique using sinusoidal phase modulation, and experimental results are discussed.

Polarizers

2019 ◽  
pp. 159-187
Author(s):  
B. D. Guenther
Keyword(s):  
Degree Of Polarization ◽  
Stokes Component ◽  
Wire Grid ◽  
Reflected Light ◽  
Half Wave ◽  
Quarter Wave ◽  
Drug Manufacturing ◽  
Measurements In Chemistry ◽  
Fresnel Formula ◽  
Birefringent Prism

Introduction to how to measure polarization and the degree of polarization, The various physical processes used to control polarization including: absorption, reflection, interference, and birefringence. An explaination of the operation of a wire grid and its molecular equivalent, a polaroid plastic are given. Fresnel formula for reflection is used to calculate the Stokes component of the reflected light. A brief introduction to the concept of birefringence is given and the various designs of birefringent prism polarizers are listed with their advantanges and shortcomings. A sample design of a prism polarizer is given. Quarter wave and half wave retarders and their use are discussed. An optional section is devoted to optical activity and the use of chiral measurements in chemistry and drug manufacturing are discussed.

scholarly journals Advances in Underwater Oil Plume Detection Capabilities

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Robyn N. Conmy ◽  
Lisa DiPinto ◽  
Amy Kukulya ◽  
Oscar Garcia-Pineda ◽  
George Graettinger ◽  
...  
Keyword(s):  
Optical Sensors ◽  
Autonomous Underwater Vehicles ◽  
Video Camera ◽  
Optical Data ◽  
Size Analysis ◽  
Large Space ◽  
Oil Concentration ◽  
Spilled Oil ◽  
Sensor Suite

Historically, visual observation is an emergency responder's first ‘tool’ in identifying spilled oil. Optical detection has since expanded to include a myriad of signals from space, aircraft, drone, vessel and submersible platforms that can provide critical information for decision-making during spill response efforts. Spill monitoring efforts below the air-water interface have been vastly improved by advances with in situ optical sensors and vehicle platform technology. Optical techniques using fluorescence, scattering, and holography offer a means to determine dissolved versus droplet fractions, provide oil concentration estimates and serve as proxies for dispersion efficiency. For subsurface spills over large space and time scales, Autonomous Underwater Vehicles (AUVs) can be used to provide subsurface plume footprints and estimate oil concentrations. For smaller, more frequent spills, tethered compact Remotely Operated Vehicles (ROVs) may be more appropriate as they are easy to deploy for rapid detection. Two underwater oil detection technologies have been developed: (1) A Remote Environmental Monitoring UnitS (REMUS-600) AUV equipped with fluorescence and backscatter SeaOWL UV-A (Oil-in-Water Locator; Sea-Bird Scientific WET Labs Inc.), holographic imager (HoloCam; SeaScan, Inc), hydrographic information, video camera, CTD and a water/oil sampler. (2) A tethered ROV system (DTG2, Deep Trekker Inc.) equipped with video camera, UviLux (Chelsea Technologies Group, Inc) fluorometer, a CTD and water/oil sampler. Calibration and validation tests of the sensor suite were conducted at the Coastal Response Research Center flume tank (NH, USA). Oil concentration estimates were verified by chemical analysis of hydrocarbons and particle size analysis (LISST 200X, Sequoia, Inc). Operational performance of the ROV platform and sensors was evaluated at the Ohmsett wave tank (NJ, USA). Field performance of the REMUS and sensor suite was evaluated at natural seeps near Santa Barbara, CA. This research demonstrates the forensic value of in situ optical data for improved understanding of the behavior and transport of spilled oil below the air-sea interface.

Numerical Simulation Calculation of Ship Submarine Oil Spill under Complicated Ocean Environment

2010 ◽  
Vol 29-32 ◽  
pp. 326-331
Author(s):  
Xiao Liang ◽  
Jun Dong Zhang ◽  
Wei Li ◽  
Jian Guo Lin
Keyword(s):  
Oil Spill ◽  
Deep Water ◽  
Sea Surface ◽  
Oil Film ◽  
Simulation Calculation ◽  
Wind Velocities ◽  
Ocean Environment ◽  
Oil Films ◽  
Spilled Oil ◽  
And Diffusion

In order to conduct the cleaning of spilled oil, to protect the marine ecological balance and to prevent the damage to marine environment by oil spill, the simulation of oil spill in deep water with the wave motion, wind and current was built by the user defined function and the volume of fluid in FLUENT. The dispersion and diffusion of oil spill in deep water was simulated dynamically. Also the oil spilling trajectories under the conditions of different current velocities, wavelengths and wind velocities were compared and analyzed, respectively. The results showed that the current, wind and wave decided the location and areas of oil films on the sea surface. The water depth influenced by the wave which increased with the increasing wavelength. Meantime, the areas of oil films on sea surface increased with current velocity decreasing, while the distance between the oil film and the source of oil increased. With the wind velocity increasing, the extended length of oil dispersion underwater and the oil film area on surface increased.

Numerical Simulation of Ship Oil Spill under Ocean Environment

2011 ◽  
Vol 121-126 ◽  
pp. 2814-2818
Author(s):  
Jia Ning Zhang ◽  
Xiao Liang ◽  
Wei Li
Keyword(s):  
Oil Spill ◽  
Deep Water ◽  
Sea Surface ◽  
Oil Film ◽  
Extended Length ◽  
Wind Velocities ◽  
Ocean Environment ◽  
Oil Films ◽  
Spilled Oil ◽  
And Diffusion

To clean the spilled oil from wreck ships and protect the marine ecological balance and prevent the damage to marine environment, the simulation of oil spill in deep water with the wave motion, wind and current was built in FLUENT platform. The dispersion and diffusion of oil spill in deep water was simulated dynamically. Also the oil spilling trajectories under the conditions of different current velocities, wavelengths and wind velocities were compared and analyzed, respectively. The results showed that the current, wind and wave decided the location and areas of oil films on the sea surface. The water depth influenced by the wave which increased with the increasing wavelength. Meantime, the areas of oil films on sea surface increased with current velocity decreasing, while the distance between the oil film and the source of oil increased. With the wind velocity increasing, the extended length of oil dispersion underwater and the oil film area on surface increased.

scholarly journals Why do mayflies lay their eggs en masse on dry asphalt roads? Water-imitating polarized light reflected from asphalt attracts Ephemeroptera.

1998 ◽  
Vol 201 (15) ◽  
pp. 2273-2286 ◽  
Author(s):  
G Kriska ◽  
G Horváth ◽  
S Andrikovics
Keyword(s):  
Polarized Light ◽  
Reproductive Activity ◽  
Egg Laying ◽  
Degree Of Polarization ◽  
The Road ◽  
Large Numbers ◽  
Reflected Light ◽  
Polarization Characteristics ◽  
Higher Temperature ◽  
Great Danger

We report on dry asphalt roads acting as 'mayfly traps'; that is, they lure swarming, mating and egg-laying mayflies in large numbers. To explain this surprising behaviour, we performed multiple-choice experiments with Ephemeroptera in the field, and measured and compared the reflection-polarization characteristics of an asphalt road and a mountain creek from which mayflies emerge. We show here that Ephemeroptera can be deceived by and attracted to dry asphalt roads because of the strongly horizontally polarized light reflected from the surface. Asphalt surfaces can mimic a highly polarized water surface to Ephemeroptera. The darker and smoother the asphalt surface, the higher is the degree of polarization of reflected light and the more attractive is the road to mayflies. We show that mayflies detect water by means of polarotaxis; that is, on the basis of the partially and horizontally polarized reflected light. Asphalt roads are excellent markers for swarming Ephemeroptera because of their conspicuous elongated form; the sky above them is usually open, which is the prerequisite of mayfly mating, and the higher temperature of the asphalt prolongs the reproductive activity of mayflies. These additional factors enhance the attractiveness of asphalt roads to swarming mayflies. Thus, asphalt roads near ephemeropteran emergence sites (lakes, rivers and creeks) are a great danger for mayflies, because eggs laid on the asphalt inevitably perish. Asphalt roads can deceive and attract mayflies en masse like the ancient tar pits and asphalt seeps or the recent crude or waste oil lakes deceive, lure and trap polarization-sensitive water-seeking insects in large numbers.

scholarly journals A Radio Polarimeter-Spectrometer

1983 ◽  
Vol 5 (2) ◽  
pp. 260-262 ◽  
Author(s):  
P.J. Hall ◽  
P.A. Hamilton ◽  
P.M. McCulloch
Keyword(s):  
Frequency Dependence ◽  
Faraday Rotation ◽  
Major Part ◽  
Stokes Parameter ◽  
Radio Signals ◽  
Polarization Characteristics ◽  
Polarization Behaviour ◽  
Spectrometer Data

The polarization characteristics of celestial radio signals are a major part of the observable nature of the radiation. Stokes polarimeters, instruments for measuring the complete polarization properties of radiation, are usually narrowband devices in order to minimise depolarization effects originating in the source or in the medium through which the radiation propagates. To measure the broadband polarization behaviour of a source, a Stokes polarimeter-spectrometer is required. Such an instrument allows the frequency dependence of each Stokes parameter to be deduced, making it possible to apply corrections to each parameter to account for known forms of polarization distortion (e.g. Faraday rotation). It is also possible to remove delay distortion from impulsive sources such as pulsars by processing the spectrometer data according to the usual de-dispersion algorithms. In some studies observation of distortion phenomena may be the major aim and a polarimeter spectrometer greatly facilitates measurements of these effects.

scholarly journals Optical 3-D Profilometry for Measuring Semiconductor Wafer Surfaces with Extremely Variant Reflectivities

2019 ◽  
Vol 9 (10) ◽  
pp. 2060 ◽  
Author(s):  
Liang-Chia Chen ◽  
Duc-Hieu Duong ◽  
Chin-Sheng Chen
Keyword(s):  
Optical Sensors ◽  
Wafer Surface ◽  
Semiconductor Wafer ◽  
Full Field ◽  
Specular Surface ◽  
Surface Profilometry ◽  
Optical Inspection ◽  
Reflected Light ◽  
Automated Optical Inspection ◽  
Light Beams

A new surface profilometry technique is proposed for profiling a wafer surface with both diffuse and specular reflective properties. Most moiré projection scanning techniques using triangulation principle work effectively on diffuse reflective surfaces, on which the reflected light beams are assumed to be well captured by optical sensors. In reality, this assumption is no longer valid when measuring a semiconductor wafer surface having both diffuse and specular reflectivities. To resolve the above problem, the proposed technique uses a dual optical sensing configuration by engaging two optical sensors at two different viewing angles, with one acquiring diffuse reflective light and the other detecting at the same time specular surface light for achieving simultaneous full-field surface profilometry. The deformed fringes measured by both sensors could be further transformed into a 3-D profile and merged seamlessly for full-field surface reconstruction. Several calibration targets and industrial parts were measured to evaluate the feasibility and accuracy of the developed technique. Experimental results showed that the technique can effectively detect diffuse and specular light with repeatability of one standard deviation below 0.3 µm on a specular surface and 2.0 µm on a diffuse wafer surface when the vertical measuring range reaches 1.0 mm. The present findings indicate that the proposed technique is effective for 3-D microscale surface profilometry in in-situ semiconductor automated optical inspection (AOI).

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