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Method of Regularized Sources for Stokes Flow Problems with Improved Calculation of Velocity Derivatives at the Boundary
wen shiting, Božidar Šarler, li ming, published scientific conference contribution abstract

Abstract: The solution of Stokes flow problems with Dirichlet and Neumann boundary conditions is performed by a non-singular Method of Fundamental Solutions which does not require artificial boundary, i.e. source points of fundamental solution coincide with the collocation points on the boundary. Instead of Dirac delta force, an exponential function, called blob, with a free parameter epsilon is employed, which limits to Dirac delta function when epsilon limits to zero. The solution of the problem is sought as a linear combination of the fields due to the regularized sources that coincide with the boundary and with their intensities chosen in such a way that the solution complies with the boundary conditions. A two-dimensional flow between parallel plates is chosen to assess the properties of the method. The results of the method are accurate except for the derivatives at the boundary. A correction of the method is proposed which can be used to properly assess also the derivatives at the boundary
Found in: osebi
Keywords: stokes flow, method of regularized sources, meshless method
Published: 28.06.2016; Views: 3015; Downloads: 0
.pdf Fulltext (247,45 KB)

Plastic Waste Precursor-Derived Fluorescent Carbon and Construction of Ternary FCs@CuO@TiO2 Hybrid Photocatalyst for Hydrogen Production and Sensing Application
Ming Fang, Matjaž Valant, Sandra Gardonio, Akansha Metha, Rayees Ahmad Rather, Blaž Belec, 2022, original scientific article

Abstract: A sustainable nexus between renewable energy production and plastic abatement is imperative for overall sustainable development. In this regard, this study aims to develop a cheaper and environmentally friendly nexus between plastic waste management, wastewater treatment, and renewable hydrogen production. Fluorescent carbon (FCs) were synthesized from commonly used LDPE (low-density polyethylene) by a facile hydrothermal approach. Optical absorption study revealed an absorption edge around 300 nm and two emission bands at 430 and 470 nm. The morphological analysis showed two different patterns of FCs, a thin sheet with 2D morphology and elongated particles. The sheet-shaped particles are 0.5 μm in size, while as for elongated structures, the size varies from 0.5 to 1 μm. The as-synthesized FCs were used for the detection of metal ions (reference as Cu2+ ions) in water. The fluorescence intensity of FCs versus Cu2+ ions depicts its upright analytical ability with a limit of detection (LOD) reaching 86.5 nM, which is considerably lesser than earlier reported fluorescence probes derived from waste. After the sensing of Cu2+, the as-obtained FCs@Cu2+ was mixed with TiO2 to form a ternary FCs@CuO@TiO2 composite. This ternary composite was utilized for photocatalytic hydrogen production from water under 1.5 AM solar light irradiation. The H2 evolution rate was found to be ~1800 μmolg−1, which is many folds compared to the bare FCs. Moreover, the optimized FCs@CuO@TiO2 ternary composite showed a photocurrent density of ~2.40 mA/cm2 at 1 V vs. Ag/AgCl, in 1 M Na2SO4 solution under the illumination of simulated solar light. The achieved photocurrent density corresponds to the solar-to-hydrogen (STH) efficiency of ~0.95%. The efficiency is due to the fluorescence nature of FCs and the synergistic effect of CuO embedded in TiO2, which enhances the optical absorption of the composite by reaching the bandgap of 2.44 eV, apparently reducing the recombination rate, which was confirmed by optoelectronic, structural, and spectroscopic characterizations.
Found in: osebi
Keywords: plastic waste, fluorescent carbo, sensing of metal ions, photocatalytic hydrogen production
Published: 25.02.2022; Views: 334; Downloads: 9
.pdf Fulltext (5,98 MB)

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