Concentration Distribution of Photosensitive Liquid in a Droplet Under Ultraviolet Light

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Tianyi Li ◽  
Aravinda Kar ◽  
Ranganathan Kumar
Keyword(s):  
Light Intensity ◽  
Flow Pattern ◽  
Concentration Distribution ◽  
Uv Light ◽  
Droplet Surface ◽  
Photosensitive Material ◽  
Rotationally Symmetric ◽  
Peak Location ◽  
Toroidal Coordinates ◽  
Rotationally Symmetric Flow

Abstract A semi-analytical solution for the concentration of photosensitive suspension is developed in a hemispherical droplet illuminated with ultraviolet (UV) laser. A biharmonic equation in stream function is analytically solved using toroidal coordinates, which is used to solve the transport equation for concentration. Flow pattern and photosensitive material concentration are affected by the peak location of the UV light intensity, which corresponds to the surface tension profile. When the laser beam is moved from the droplet center to its edge, a rotationally symmetric flow pattern changes from a single counter clockwise circulation to a circulation pair and finally to a single clockwise circulation. This modulation in the orientation of circulation modifies the concentration distribution of the photosensitive material. The distribution depends on both diffusion from the droplet surface and the Marangoni convection. The region beneath the droplet surface away from the UV light intensity peak has low concentration, while the region near the downward dividing streamline has the highest concentration. When the UV light peak reaches the droplet edge, the concentration is high everywhere in the droplet.

Concentration Distribution of Photosensitive Liquid in a Droplet Under UV Light

2019 ◽  
Author(s):  
Tianyi Li ◽  
Aravinda Kar ◽  
Ranganathan Kumar
Keyword(s):  
Light Intensity ◽  
Flow Pattern ◽  
Concentration Distribution ◽  
Uv Light ◽  
Droplet Surface ◽  
Photosensitive Material ◽  
Peak Location ◽  
Toroidal Coordinates ◽  
Rotationally Symmetric Flow ◽  
Mass Transport Equation

Abstract A semi-analytical solution for the concentration of photosensitive suspension is developed in a hemispherical droplet illuminated with UV laser. A biharmonic equation in stream function is analytically solved using toroidal coordinates and the velocity is then used to solve the mass transport equation for concentration. Flow pattern and photosensitive material concentration are affected by the peak location of the UV light intensity, which corresponds to a surface tension profile. When the laser beam is moved from the droplet center to its edge, a rotationally symmetric flow pattern changes from a single counter clockwise circulation to a circulation pair and finally to a single clockwise circulation. This modulation in the orientation of circulation modifies the concentration distribution of the photosensitive material. The distribution depends on both diffusion from the droplet surface as well as Marangoni convection. The region beneath the droplet surface away from the UV light intensity peak has low concentration, while the region near the downward dividing streamline has the highest concentration. When the UV light peak reaches the droplet edge, the concentration is high everywhere in the droplet.

Rotationally symmetric flow of Reiner-Rivlin fluid over a heated porous wall using numerical approach

2021 ◽  
pp. 095440622110342
Author(s):  
Talat Rafiq ◽  
M Mustafa ◽  
Junaid Ahmad Khan
Keyword(s):  
Boundary Layer ◽  
Layer Structure ◽  
Full Range ◽  
Porous Wall ◽  
Symmetric Flow ◽  
Axial Velocity Component ◽  
Suction Velocity ◽  
Rotationally Symmetric ◽  
Non Linear System ◽  
Rotationally Symmetric Flow

This research features one parameter family of solutions representing rotationally symmetric flow of non-Newtonian fluid obeying Reiner-Rivlin model. Such flows take place over a revolving plane permeable surface through origin such that fluid at infinity also undergoes uniform rotation about the vertical axis. Heat transfer accompanied with viscous heating effect is also analyzed. A similarity solution is proposed that results into a coupled non-linear system with four unknowns. Boundary layer structure is characterized by a parameter [Formula: see text] that compares angular velocity of external flow with that of the rotating surface. Solutions are developed by a well-known package bvp4c of MATLAB for full range of [Formula: see text]. Flow pattern for different choices of [Formula: see text] is scrutinized by computing both 2 D and 3 D streamlines. It is further noted that value of suction velocity is important with regards to the sign of axial velocity component. Boundary layer suppresses considerably whenever the surface is permeable. For sufficiently high suction velocity with [Formula: see text], entire fluid undergoes rigid body rotation. In no suction case, axially upward flow accelerates for increasing values of parameter [Formula: see text] in the range [Formula: see text], whereas opposite trend is apparent in the case [Formula: see text]. Results for normalized wall shear and Nusselt number are scrutinized for various choices of embedded parameters.

scholarly journals Photodegradation of Trace Trichloronitromethane in Water under UV Irradiation

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Lin Deng ◽  
Zhiren Wu ◽  
Caiqian Yang ◽  
Yung-Li Wang
Keyword(s):  
Humic Acid ◽  
Light Intensity ◽  
Uv Light ◽  
Control Strategies ◽  
Chloride Ions ◽  
Source Control ◽  
Photochemical Degradation ◽  
Nitrate Ions ◽  
Photodegradation Rate ◽  
Water And Wastewater

This study’s objective was to study the photodegradation of TCNM (trichloronitromethane) in water under UV light. The effects of light intensity, nitrate ions, chloride ions, humic acid, and pH on the photochemical degradation of TCNM were investigated under the irradiation of low pressure mercury lamp (λ= 254 nm, 12 W). The photodegradation rate of TCNM was found to increase with increasing the concentration of nitrate ions, chloride ions, humic acid, pH, and light intensity. The photodegradation of TCNM was examined at pH 6.0 with initial concentrations (C0) of TCNM at 10.0–200.0 µg/L. The overall rate of degradation of TCNM was modeled using a pseudofirst-order rate law. Finally, the proposed mechanism involved in the photodegradation of TCNM was also discussed by analysis. Results of this study can contribute to the development of new source control strategies for minimization of TCNM risk at drinking water and wastewater utilities.

scholarly journals Planar droplet sizing: Application to a spray of Jet A1 kerosene

2017 ◽  
Author(s):  
Pierre Doublet ◽  
Christine Lempereur ◽  
Virginel Bodoc ◽  
Mikael Orain ◽  
Pierre Gajan
Keyword(s):  
Light Intensity ◽  
Scattered Light ◽  
Droplet Surface ◽  
Scattered Light Intensity ◽  
Field Of View ◽  
Fluorescence Signal ◽  
Droplet Volume ◽  
Image Processing Algorithm ◽  
Two Phase ◽  
Scattering Angle

Optical techniques are  widely employed for their non-intrusive behavior and are applied to two-phase flowinvestigations. Until now, the most commonly used technique to determine the droplet size is the Phase Doppler Anemogranulometry, although it is time consuming for an overall injector characterization. An imaging technique called Planar Droplet Sizing has been used to offer an alternative and provide a spatially-resolved 2D map of the Sauter Mean Diameter (SMD). The measurement is based on the ratio between laser-induced fluorescence and scattered light intensities which are assumed to be proportional respectively to the droplet volume and droplet surface area. However, previous studies revealed that the dependence of fluorescence intensity on the droplet volume can be altered by the absorption of light in the liquid. The scattered light intensity depends on the scattering angle and intensity variations within the field of view must be avoided.The aim of this study is to make the PDS technique operational for a Jet A-1 kerosene spray. A strong absorption of liquid kerosene appears under UV excitation at 266 nm making the technique unsuitable. Under visible excitation at 532 nm, a fluorescent tracer (Pyrromethene 597) must be added to the kerosene to enhance the fluorescence signal. To prevent scattered light intensity variations within the field of view, an optimal scattering angle close to 115° is required. An image processing algorithm is proposed in order to reduce the effects ofmultiple scattering.DOI: http://dx.doi.org/10.4995/ILASS2017.2017.4698

scholarly journals Treatment of High-Strength Animal Industrial Wastewater Using Photo-Assisted Fenton Oxidation Coupled to Photocatalytic Technology

Water ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1553 ◽  
Author(s):  
Jae Hong Park ◽  
Dong Seok Shin ◽  
Jae Kwan Lee
Keyword(s):  
Light Intensity ◽  
Removal Efficiency ◽  
Industrial Wastewater ◽  
Uv Light ◽  
High Strength ◽  
Cod Removal ◽  
Fenton Oxidation ◽  
Optimal Conditions ◽  
Experimental Conditions ◽  
Animal Wastewater

Animal wastewater is one of the wastewaters that has a color and is difficult to treat because it contains a large amount of non-degradable organic materials. The photo-assisted Fenton oxidation technique was applied to treat animal wastewater, and the optimal conditions of chemical oxygen demands (COD) removal were analyzed according to changes in pH, ferrous ion, H2O2, and ultraviolet (UV) light intensity as a single experimental condition. Experimental results showed that, under the single-factor experimental conditions, the optimal conditions for degradation of animal wastewater were pH 3.5, Fe(II) 0.01 M, H2O2 0.1 M, light intensity 3.524 mW/m2. Under the optimal conditions, COD removal efficiency was 91%, sludge production was 2.5 mL from 100 mL of solution, color removal efficiency was 80%, and coliform removal efficiency was 99.5%.

scholarly journals Dual-Wavelength (UV and Blue) Controlled Photopolymerization Confinement for 3D-Printing: Modeling and Analysis of Measurements

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1819 ◽  
Author(s):  
Jui-Teng Lin ◽  
Da-Chuan Cheng ◽  
Kuo-Ti Chen ◽  
Hsia-Wei Liu
Keyword(s):  
Light Intensity ◽  
Blue Light ◽  
Uv Light ◽  
Numerical Data ◽  
Coupling Factor ◽  
Dual Wavelength ◽  
Continuous Exposure ◽  
Initiator Concentration ◽  
Modeling And Analysis ◽  
Inhibition Effect

The kinetics and modeling of dual-wavelength (UV and blue) controlled photopolymerization confinement (PC) are presented and measured data are analyzed by analytic formulas and numerical data. The UV-light initiated inhibition effect is strongly monomer-dependent due to different C=C bond rate constants and conversion efficacies. Without the UV-light, for a given blue-light intensity, higher initiator concentration (C10) and rate constant (k’) lead to higher conversion, as also predicted by analytic formulas, in which the total conversion rate (RT) is an increasing function of C1 and k’R, which is proportional to k’[gB1C1]0.5. However, the coupling factor B1 plays a different role that higher B1 leads to higher conversion only in the transient regime; whereas higher B1 leads to lower steady-state conversion. For a fixed initiator concentration C10, higher inhibitor concentration (C20) leads to lower conversion due to a stronger inhibition effect. However, same conversion reduction was found for the same H-factor defined by H0 = [b1C10 − b2C20]. Conversion of blue-only are much higher than that of UV-only and UV-blue combined, in which high C20 results a strong reduction of blue-only-conversion, such that the UV-light serves as the turn-off (trigger) mechanism for the purpose of spatial confirmation within the overlap area of UV and blue light. For example, UV-light controlled methacrylate conversion of a glycidyl dimethacrylate resin is formulated with a tertiary amine co-initiator, and butyl nitrite. The system is subject to a continuous exposure of a blue light, but an on-off exposure of a UV-light. Finally, we developed a theoretical new finding for the criterion of a good material/candidate governed by a double ratio of light-intensity and concentration, [I20C20]/[I10C10].

Kinetic Study of Photoinitiated Frontal Polymerization. Influence of UV Light Intensity Variations on the Conversion Profiles

2010 ◽  
Vol 43 (1) ◽  
pp. 177-184 ◽  
Author(s):  
N. Hayki ◽  
L. Lecamp ◽  
N. Désilles ◽  
P. Lebaudy
Keyword(s):  
Light Intensity ◽  
Kinetic Study ◽  
Uv Light ◽  
Frontal Polymerization

Uniform and Gaussian UV Light Intensity Distribution on Droplet for Selective Area Deposition of Particles

2020 ◽  
Author(s):  
Tianyi Li ◽  
Aravinda Kar ◽  
Ranganathan Kumar
Keyword(s):  
Sessile Drop ◽  
Uv Light ◽  
Incident Light ◽  
Droplet Surface ◽  
Light Distribution ◽  
Surface Tension Gradient ◽  
Sharp Change ◽  
Sessile Droplet ◽  
Selective Area ◽  
Light Profiles

Abstract Particle transport through Marangoni convection inside a sessile droplet can be controlled by the UV light distribution on the surface. The photosensitive solution changes the surface tension gradient on the droplet surface and can induce clockwise and counter-clockwise circulations depending on the incident light distribution. In this paper, the stream function in the sessile drop has been evaluated in toroidal coordinates by solving the biharmonic equation. Multiple primary clockwise and counter-clockwise circulations are observed in the droplet under various concentric UV light profiles. The downward dividing streamlines are expected to deposit the particles on the substrate, thus matching the number of deposited rings on the substrate with the number of UV light rings. Moffatt eddies appear near the contact line or centerline of the droplet either due to a sharp change in the UV light profile or because the illuminated region is away from them.

scholarly journals Removal of Polyvinyl Alcohol Using Photoelectrochemical Oxidation Processes Based on Hydrogen Peroxide Electrogeneration

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Kai-Yu Huang ◽  
Chih-Ta Wang ◽  
Wei-Lung Chou ◽  
Chi-Min Shu
Keyword(s):  
Hydrogen Peroxide ◽  
Light Intensity ◽  
Removal Efficiency ◽  
Flow Rate ◽  
Current Density ◽  
Uv Light ◽  
Supporting Electrolyte ◽  
Oxygen Flow Rate ◽  
Oxygen Flow ◽  
Solution Ph

This study investigates the removal efficiency of PVA from aqueous solutions using UV irradiation in combination with the production of electrogenerated hydrogen peroxide (H2O2) at a polyacrylonitrile-based activated carbon fiber (ACF) cathode. Three cathode materials (i.e., platinum, graphite, and ACF) were fed with oxygen and used for the electrogeneration of H2O2. The amount of electrogenerated H2O2produced using the ACF cathode was five times greater than that generated using the graphite cathode and nearly 24 times greater than that from platinum cathode. Several parameters were evaluated to characterize the H2O2electrogeneration, such as current density, oxygen flow rate, solution pH, and the supporting electrolyte used. The optimum current density, oxygen flow rate, solution pH, and supporting electrolyte composition were found to be 10 mA cm−2, 500 cm3 min−1, pH 3, and Na2SO4, respectively. The PVA removal efficiencies were achieved under these conditions 3%, 16%, and 86% using UV, H2O2electrogeneration, and UV/H2O2electrogeneration, respectively. A UV light intensity of 0.6 mW cm−2was found to produce optimal PVA removal efficiency in the present study. A simple kinetic model was proposed which confirmed pseudo-first-order reaction. Reaction rate constant (kap) was found to depend on the UV light intensity.

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