Light Refraction Effects Research Articles

Treatment of antibiotics in mariculture wastewater via phosphate-doped porous coralline carbon nitride/porous mullite honeycomb sunlight-driven photocatalytic system: Morphological control, long-term and continuous flow application

Herein, this study describes a promising sunlight-driven photocatalytic system designed for the elimination of antibiotics (e.g., fluoroquinolones and sulfonamides) in real maricultural wastewater. Phosphate-doped porous coralline carbon nitride (P-CCN), synthesized by controlling morphology from two-dimensional block CN, was immobilized onto porous mullite honeycomb to construct a practical and molding photocatalytic system (P-CCN/PMH). By leveraging its microscopic porous coral structure, P-CCN displayed an augmentation in surface-active sites and a notable inner light refraction effect. This enhancement contributed to the high-efficiency performance of P-CCN/PMH system, producing 8.232 mM·h−1·g−1 H2O2 under sunlight, which was 7.21-fold higher than before modification; and its degradation rate constant to enrofloxacin (0.263 min−1) was 39.31-fold higher. The P-CCN/PMH system demonstrated superior capability in terms of adaptability to a wide concentration range, acid-alkali conditions, mineralization, carbon reduction, and challenging ionic surroundings or water matrices. Crucial superoxide radicals have been confirmed through mass-spectrometric technique and theoretical calculations, leading to ring-opening effects. Long-term and continuous-flow experiments were deeply carried out, validating the commendable competence of the P-CCN/PMH photocatalytic system in simulated wastewater treatment scenarios. Ultimately, the aggregate results highlight valuable insights into coralline materials synthesis and modular catalyst construction, presenting potential for addressing challenges related to environmental antibiotics pollution.

Decorative effect of light refraction in glass

Decorative effect of light refraction in glass

Distorted underwater image reconstruction for an autonomous underwater vehicle based on a self-attention generative adversarial network.

Imaging through the wavy air-water surface suffers from severe geometric distortions, which are caused by the light refraction effect that affects the normal operations of underwater exploration equipment such as the autonomous underwater vehicle (AUV). In this paper, we propose a deep learning-based framework, namely the self-attention generative adversarial network (SAGAN), to remove the geometric distortions and restore the distorted image captured through the water-air surface. First, a K-means-based image pre-selection method is employed to acquire a less distorted image that preserves much useful information from an image sequence. Second, an improved generative adversarial network (GAN) is trained to translate the distorted image into the non-distorted image. During this process, the attention mechanism and the weighted training objective are adopted in our GAN framework to get the high-quality restored results of distorted underwater images. The network is able to restore the colors and fine details in the distorted images by combining the three objective losses, i.e., the content loss, the adversarial loss, and the perceptual loss. Experimental results show that our proposed method outperforms other state-of-the-art methods on the validation set and our sea trial set.

Universal algorithm for water depth refraction correction in through-water stereo remote sensing

In through-water stereo remote sensing, the correction of the effect of light refraction on water depth determination is an unsolved problem. The challenge is that no solution exists for apparent positions when the conjugate image rays are non-intersecting. This paper proposes a new water depth refraction correction algorithm for through-water stereo remote sensing. The midpoint of the shortest line segment between two non-intersecting conjugate image rays is used as the apparent position, so that the mathematical relationship between the apparent and actual depths is established under the “no solution condition”. The new algorithm is reasonable and applicable whether or not conjugate image rays are intersecting. Compared with the existing algorithms, the new algorithm can improve bathymetric accuracy in different degrees. The improvement becomes more significant as the off-nadir view angle difference and the depth increase. Results for Area 1 showed that, compared with the three existing algorithms, the new algorithm improved RMSE accuracy by about 22%, 29% and 24% respectively. The new algorithm enables reasonable water depth refraction correction to be implemented in any case (whether conjugate image rays are intersecting or not).

Light refraction effects in counterflow non-premixed flames

This paper presents the influence of light refraction on the broadening of CH∗ and C2∗ species experimental profiles in laminar counterflow non-premixed flames. In fact, by comparing CH∗ and C2∗ experimental and numerical profiles in a counterflow configuration, a broadening of these species experimental profiles is observed, and these species are frequently employed experimentally to determine important macroscopic combustion properties. Therefore in this work, in order to give an explanation of these phenomena, light refraction due to a high temperature gradient was considered. The Gladstone–Dale relation was used to estimate the medium refractive index along the burner axis, taking into account the gas density and composition. Then, a simple procedure for light refraction estimation of rays reaching the solid angle of the camera in counterflow non-premixed flames was proposed. Finally, the influence of refraction of light on CH∗ and C2∗ species thicknesses appears to be significant depending on the operating conditions of counterflow non-premixed flames. However, taking into account the difference between the experimental and numerical profiles thicknesses, this effect is not fully responsible for the experimental broadening. Nonetheless, the same procedure described here can be used in order to study the light refraction for other experimental configurations, such as those of transcritical flames, where the gas density variation is much higher, and consequently the light refraction would be greater.

Rheological behavior of human blood in uniaxial extensional flow

We present an investigation of the rheological behavior of whole human blood under uniaxial extensional flow. For that purpose, capillary breakup experiments were carried out by combining the slow retraction method, high-speed imaging techniques, and an immiscible oil bath. The use of the oil bath was aimed at reducing liquid loss by evaporation and to reduce light refraction effects, thus allowing the visualization of the blood cells during the filament thinning. Extensional relaxation times were measured in whole blood samples collected from a total of 13 healthy adult volunteers from both genders, with hematocrit levels between 38.7% and 46.3%. For this range of red blood cell concentrations, the variation of the extensional relaxation time is small, with the average extensional relaxation times measured in air and in oil being 114 ± 30 and 259 ± 47 μs, respectively. An increase of the red blood cells concentration leads to an increase of the bulk viscosity of the sample, which delays the thinning of the filament and consequently the time to breakup. In addition, blood aging was found to reduce the relaxation time while the absence of anticoagulant increases it significantly.

Study on the reconstruction method of stereo vision in glass flume

In three-dimensional reconstruction experiments based on stereo vision theory in a glass flume, there is usually more than one medium in the travel path of the light, such as air, glass and water. These media not only degrade image quality, but also change the light route. Large errors are generated if the effects of these media are ignored. To solve the problems of media effects, a new method of object reconstruction for the glass flume is proposed, based on computer vision theory and laws of refraction. Firstly, the light refraction effects are analyzed and a coordinate correction formula is developed. Secondly, correction parameters are obtained based on a stereo vision method to correct the coordinates of a target point. Finally, model experiments in glass flume are described and the errors are analyzed. The experimental results show that the proposed method is effective in correcting refraction distortion, and improves the accuracy of three-dimensional reconstruction of target points.

Effect of refracted light distribution on the photoelastic generation of zero-group velocity Lamb modes in optically low-absorbing plates.

Zero-group velocity (ZGV) Lamb modes are associated with sharp local acoustic resonances and allow, among other features, local measurement of Poisson's ratio. While the thermoelastic generation of Lamb waves in metal plates has been widely studied, the case of materials of low-optical absorption remains unexplored. In materials such as glasses, the generation of bulk elastic waves has been demonstrated to be sensitive to the refracted light distribution. In this paper, a detailed analysis of the effect of light refraction on the laser-based generation of ZGV Lamb modes is presented. Experiments are performed on a bare glass plate without the need for an additional layer for light absorption or reflection. Using an appropriate tilted volume source, it is shown that the laser-ultrasonic technique allows non-contact measurement of the Poisson's ratio.

The Cherenkov Radiation in the Galaxy’s Halo of Dark Matter

The effect of light refraction in a galaxy’s halo of dark matter, described by profiles of Navarro-Frenk-White and Burkert, was considered. Powers of the Cherenkov radiation for the refractive indexes of gravitational fields with these profiles were calculated. It was shown that correspondent radiation temperature in the X-rays diapason have the magnitude about T~10-6K . It was also marked that its detection may be the criteria on choosing the preferable dark matter density distribution in a galaxy.

魚眼ステレオカメラを用いた水中物体の3次元計測

Sensing in aquatic environments is important to maintain underwater structures and research aquatic life. This paper proposes a 3D measurement method of objects in water using a fish-eye stereo camera. Aquatic sensing meets the difficulty of 3D measurement because of light refraction due to the difference of refractive indices of air and water. This problem is enhanced by distortion of fish-eye images. The proposed method removes distortion of fish-eye images by converting them to perspective projection images. The corrected images are searched for corresponding points and measurement points are located by triangulation. The effect of light refraction is considered by ray tracing to measure accurately in aquatic environments. Experimental results show the effectiveness of the proposed method.

Secondary flow patterns and mixing in laminar pulsating flow through a curved pipe

Mixing by secondary flow is studied by particle image velocimetry (PIV) in a developing laminar pulsating flow through a circular curved pipe. The pipe curvature ratio is η = r0/rc = 0.09, and the curvature angle is 90°. Different secondary flow patterns are formed during an oscillation period due to competition among the centrifugal, inertial, and viscous forces. These different secondary-flow structures lead to different transverse-mixing schemes in the flow. Here, transverse mixing enhancement is investigated by imposing different pulsating conditions (Dean number, velocity ratio, and frequency parameter); favorable pulsating conditions for mixing are introduced. To obviate light-refraction effects during PIV measurements, a T-shaped structure is installed downstream of the curved pipe. Experiments are carried out for the Reynolds numbers range 420 ≤ Rest ≤ 1,000 (Dean numbers 126.6 ≤ Dn ≤ 301.5) corresponding to non-oscillating flow, velocity component ratios 1 ≤ (β = Umax,osc/Um,st) ≤ 4 (the ratio of velocity amplitude of oscillations to the mean velocity without oscillations), and frequency parameters 8.37 < (α = r0(ω/ν)0.5) < 24.5, where α2 is the ratio of viscous diffusion time over the pipe radius to the characteristic oscillation time. The variations in cross-sectional average values of absolute axial vorticity (|ζ|) and transverse strain rate (|e|) are analyzed in order to quantify mixing. The effects of each parameter (Rest, β, and α) on transverse mixing are discussed by comparing the dimensionless vorticities (|ζP|/|ζS|) and dimensionless transverse strain rates (|eP|/|eS|) during a complete oscillation period.

The behavior of protons during wet olivine deformation under the conditions of the kimberlite process

This paper reports the results of optical and electron microscopic investigations of mantle olivine samples with H2O contents of tens-hundreds ppm weight. Samples were obtained from the xenoliths and xenocrysts of the Udachnaya pipe. At the scale of optical microscope magnification, a peculiar banded microstructure was observed in thin sections prepared parallel to the olivine (010) plane. It is formed by cross-hatched bands parallel to four crystallographic directions of the olivine structure: [100], [001], [101], and [−101]. At the scale of electron optical magnifications, the banded microstructure is observed as nanometer-sized heterogeneities of various types which are related to olivine deformation: (a) planar defects parallel to (100) and (001) corresponding to the (100)[010] and (001)[100] dislocation glide systems, respectively; they are occasionally transformed into lamellae or decorated by nanoinclusions; and (b) nanometer-sized heterogeneities formed by nanoinclusion arrays not related to planar defects and oriented along the same directions of the olivine structure as the optically visible bands. The deformation structures are decorated by coupled point OH-bearing defects, which were initially present in the olivine. The crystallographically oriented arrays of nanoinclusions of high-pressure hydrous silicates are considered as a result of olivine deprotonization (elimination of OH-bearing defects from the olivine structure) in the zones of previous deformation compression in the crystal. Light refraction effects on the nanoinclusions make these zones optically visible and produce the banded microstructure, which is a consequence of previous deformation.

A Photogrammetric Correction Procedure for Light Refraction Effects at a Two-Medium Boundary

A Photogrammetric Correction Procedure for Light Refraction Effects at a Two-Medium Boundary

Accurate determination of embedded particles within dispersed elements in multiphase dispersions, using a 3D micro-stereoscopic vision system

A wide range of industrial operations involve the mixing of multiple phases, where the interfacial area between the phases determines the performance of the system. Interactions between phases occur, giving rise to the formation of complex structures containing, for example, air bubbles and small water droplets, trapped in the organic/oil drops. A two-dimensional observation of this phenomenon may lead to an erroneous determination of the amount of dispersed elements and the actual interaction between them, since bubbles and drops coming from different focal planes may appear overlapped. In this work, a method that allows the accurate determination of embedded particles within dispersed elements was developed and validated. By using micro-stereoscopic on-line image acquisition techniques, accurate images from a four-phase system model simulating a fermentation broth were acquired to identify and count the oil-trapped particles moving at high speed. Light refraction effects within embedded particles were considered to obtain highest accuracy. The total error of the measurement system was mainly due to the magnification used for the stereo-microscope and the size range of particles to be measured, being as low as ± 5.7 % for × 6 magnification and particles as small as 250 μ m . Moreover, 3D results clearly indicated that bi-dimensional observations lead to an erroneous evaluation of the extent of the particles trapped (overestimated by up to 30%) since different focal planes may be overlapped. This original method permits to postulate very accurate models for mass transfer, based on experimental evidence of the actual multiphase systems.

A Photogrammetric Correction Procedure for Light Refraction Effects at a Two-Medium Boundary

We report on a correction procedure for light refraction effects at a two-medium boundary, based on the stereo view of underwater objects, to estimate underwater topography using photogrammetry. Because theoretically, no solution exists for photogrammetrically observed positions when the incident angles of light rays from an underwater object of interest to two cameras are different; approximation in solving the positions is needed. We show the feasibility of the approximation theoretically by examining the horizontal differences between the observed and true positions when objects are in line along an airplane track or when the incident angles are identical. We applied the procedure to bathymetric mapping of Shiraho Reef, southwest Japan, using a stereo-pair of aerial photographs. Comparison of the corrected depths with measured depths at 658 points showed a mean error and standard deviation of 20.06 m and 0.36 m, respectively, for measured depth range of 23.4 m to 20.2 m.

Nonuniform illumination of laser spherical targets

We studied the smoothing of nonuniformities in the quasisteady expansion of a plasm ablated from a spherical target under a weakly nonuniform laser irradiation with overall heat conduction and magnetic generation effects. We also considered light refraction effects.

Light refraction from air in glass in the case of light beam departure from the refracting surface

The effect of light refraction in the case of a light beam departing from the refracting face of a prism is examined in this paper. It is established that the refracted flux diminishes to zero as the angle of departure increases to 14°; the angle of refraction is independent of the angle of departure, and equals the angle of refraction of glazing rays. The nature of the distribution of the refracted ray intensity along the refracting face is determined. Data are presented about the intensity distribution in the refracted beam at the exit from the prism and in the plane of the radiation detector.