The improvement of numerical modeling in the solution of incompressible viscous flow problems using finite element method based on spherical Hankel shape functions

In this paper, the finite element method with new spherical Hankel shape functions is developed for simulating 2‐dimensional incompressible viscous fluid problems. In order to approximate the hydrodynamic variables, the finite element method based on new shape functions is reformulated. The governing equations are the Navier‐Stokes equations solved by the finite element method with the classic Lagrange and spherical Hankel shape functions. The new shape functions are derived using the first and second kinds of Bessel functions. In addition, these functions have properties such as piecewise continuity. For the enrichment of Hankel radial basis functions, polynomial terms are added to the functional expansion that only employs spherical Hankel radial basis functions in the approximation. In addition, the participation of spherical Bessel function fields has enhanced the robustness and efficiency of the interpolation. To demonstrate the efficiency and accuracy of these shape functions, 4 benchmark tests in fluid mechanics are considered. Then, the present model results are compared with the classic finite element results and available analytical and numerical solutions. The results show that the proposed method, even with less number of elements, is more accurate than the classic finite element method.     

Microwave-assisted green synthesis of 4,5-dihydro-1<Emphasis Type="Italic">H</Emphasis>-pyrazole-1-carbothioamides in water

Rapid, efficient, simple and green procedure for the synthesis of 4,5-dihydro-1H-pyrazole-1-carbothioamides via the multicomponent reaction of aryl aldehydes, acetophenones and thiosemicarbazide in water in the presence of tetrabutylammonium hydroxide under microwave irradiation is reported.     

Studying Natural Buckyballs and Buckybowls in Fossil Materials

Buckyballs (fullerenes) were first reported over 30 years ago, but still little is known regarding their natural occurrence, since they have so far only been found at sites of high‐energy incidents, such as lightning strikes or meteor impacts, but have not been reported in low‐energy materials like fossil fuels. Using ultrahigh‐resolution mass spectrometry, a wide range of fullerenes from C₃₀ to C₁₁₄ was detected in the asphaltene fraction of a heavy crude oil, together with their building blocks of C_10nH₁₀ stoichiometry. High‐level DLPNO‐CCSD(T) calculations corroborate their stability as spherical and hemispherical species. Interestingly, the maximum intensity of the fullerenes was found at C₄₀ instead of the major fullerene C₆₀. Hence, experimental evidence supported by calculations show the existence of not only buckyballs but also buckybowls as 3‐dimensional polyaromatic compounds in fossil materials.     

Proposal of an infrared electro-optic switch based on grapheme–silicone–graphene metamaterial with electrically dynamic tunability

Optical Review - The electrically dynamic tunability of a proposed metamaterial switch based on graphene–silicene–graphene heterogeneous structure is theoretically investigated in the...     

Smart inverters with broadband light absorption enhancement of nanostructure plasmonic solar absorber using PSO algorithms and FDTD method

Optical Review - Solar plasmonics absorbers have received outstanding interest from nanotechnology. However, they have small efficiency. To overcome this challenge, we have used two ways in this...     

Caffeine-H3PO4: a novel acidic catalyst for various one-pot multicomponent reactions

Research on Chemical Intermediates - Caffeine-H3PO4 along with caffeine-HClO4 and caffeine-HNO3 have been prepared and applied for one-pot preparation of bis(indolyl) methanes,...     

DABCO-catalyzed multi-component domino reactions for the one-pot efficient synthesis of diverse and densely functionalized benzofurans in water

Research on Chemical Intermediates - An efficient, three-component strategy for the improved synthesis of a pharmaceutically interesting diverse kind of multi-functionalized benzofurans via one-pot...