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41.
A sharp‐interface immersed boundary framework for simulations of high‐speed inviscid compressible flows 下载免费PDF全文
Shuvayan Brahmachary Ganesh Natarajan Vinayak Kulkarni Niranjan Sahoo 《国际流体数值方法杂志》2018,86(12):770-791
A new finite‐volume flow solver based on the hybrid Cartesian immersed boundary (IB) framework is developed for the solution of high‐speed inviscid compressible flows. The IB method adopts a sharp‐interface approach, wherein the boundary conditions are enforced on the body geometry itself. A key component of the present solver is a novel reconstruction approach, in conjunction with inverse distance weighting, to compute the solutions in the vicinity of the solid‐fluid interface. We show that proposed reconstruction leads to second‐order spatial accuracy while also ensuring that the discrete conservation errors diminish linearly with grid refinement. Investigations of supersonic and hypersonic inviscid flows over different geometries are carried out for an extensive validation of the proposed flow solver. Studies on cylinder lift‐off and shape optimisation in supersonic flows further demonstrate the efficacy of the flow solver for computations with moving and shape‐changing geometries. These studies conclusively highlight the capability of the proposed IB methodology as a promising alternative for robust and accurate computations of compressible fluid flows on nonconformal Cartesian meshes. 相似文献
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Ranjan Patra Israel Goldberg 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(8):819-821
The synthesis is reported of the tricarboxylic acid 3‐(3,5‐dicarboxybenzyloxy)benzoic acid (H3L) and the product of its reaction under solvothermal conditions with ZnII cations, namely poly[[μ6‐3‐(3,5‐dicarboxylatobenzyloxy)benzoato](dimethylformamide)‐μ3‐hydroxido‐dizinc(II)], [Zn2(C16H9O7)(OH)(C3H7NO)]n, the formation of which is associated with complete deprotonation of H3L. Its crystal structure consists of a single‐framework coordination polymer of the organic L3− ligand with ZnII cations in a 1:2 ratio, with additional hydroxide and dimethylformamide (DMF) ligands coordinated to the ZnII centres. The ZnII cations are characterized by coordination numbers of 5 and 6, being bridged to each other by hydroxide ligands. In the polymeric framework, the carboxylate‐ and hydroxy‐bridged ZnII cations are arranged in coordination‐tessellated columns, which propagate along the a axis of the crystal structure, and each L3− ligand links to seven different ZnII centres via Zn—O bonds of two different columns. The coordination framework, composed of [Zn2(L)(OH)(DMF)]n units, forms an open architecture, the channel voids within it being filled by the zinc‐coordinating DMF ligands. This report provides the first structural evidence for the formation of coordination polymers with H3L via multiple metal–ligand bonds through its carboxylate groups.<!?tpb=21.5pt> 相似文献
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Sitaram Pal Sukumar Ghosh Bimal K. Banik Shaikh Khairul Alam Usha Ranjan Ghatak 《合成通讯》2013,43(14):2203-2216
The bridged-ethers, (±)-2-methoxy-9a-carbamorphinan (1b) and (±)-2-methoxy-9a-carba-14α-morphinan(2b) have been synthesized. The acid-catalyzed cyclizations of 1-m-methoxy benzyloctalone 3b and 1-m-methoxybenzyloctalins 4b proceed with high regio-and stereoselectivities leading mostly to the bridged-ketone 14 and ether 1b respectively, along with o-methoxy-tetracyclic ketone 15 and the ether 17, in addition to other minor products. 相似文献
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Laxminarayan Sahoo Anadi Singhamahapatra Katuri J.V. PaulDuraikkannu Loganathan 《Tetrahedron letters》2013
A method for the chemoselective reduction of glycopyranosyl azides using SnCl4 and tin metal as the reducing agent followed by in situ chloroacetylation of the synthesized glycopyranosyl amine was developed. This reaction is applicable to diversely functionalized glycopyranosyl azides for the synthesis of glycopyranosyl chloroacetamides. 相似文献
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Madhumanchi Sreenu Rati Ranjan Nayak Yedla Poornachandra C. Ganesh Kumar 《Journal of Dispersion Science and Technology》2013,34(6):765-771
Synthesized sodium N-pamitoyl amino acids were evaluated for surface and antimicrobial properties and compared with sodium lauryl sulfate (SLS). Emulsion stability of the amino acid surfactants and calcium tolerance of the sodium N-palmitoyl isoleucine were better as compared to SLS. Wetting ability and foaming properties of the palmitic acid-based surfactants were inferior to SLS. N-Acyl amino acids exhibited better antibacterial activity compared to sodium salts of N-acyl amino acids and standard compounds against Staphylococcus aureus MLS-16 and Bacillus subtilis. These studies revealed that the palmitoyl amino acid surfactants can be exploited in household, skin care formulations, and industrial applications. 相似文献
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Bikash Ranjan Sahoo Banikalyan Swain Manas Ranjan Dikhit Madhubanti Basu Aritra Bej Pallipuram Jayasankar Mrinal Samanta 《Applied biochemistry and biotechnology》2013,170(6):1282-1309
The nucleotide-binding oligomerization domain 1 (NOD1) receptor recognizes various pattern-associated structures of microbes through its leucine-rich repeat (LRR) domain and activates signaling cascades to induce innate immunity. This report describes the activation of NOD1 receptor signaling by gamma-d-glutamyl-meso-diaminopimelic acid (or γ-D-Glu-mDAP [iE-DAP]) in a commercially important fish species, rohu (Labeo rohita). It also described critical motifs in the NOD1-LRR domain that could be involved in binding iE-DAP, lipopolysaccharide (LPS), and polyinosinic:polycytidylic acid (poly I:C). The activation of NOD1 receptor signaling was studied by injecting iE-DAP, and analysis of tissue samples for NOD1 and receptor-interacting serine/threonine kinase (RICK) expression was done by quantitative real-time polymerase chain reaction (qRT-PCR) assay. To identify ligand-binding motifs in NOD1, the 3D model of NOD1-LRR was generated, followed by a 6-ns molecular dynamics simulation. Molecular docking of LPS with NOD1-LRR was executed at the Hex and PatchDock servers, and iE-DAP and poly I:C in the AutoDock 4.2, FlexX 2.1, Glide 5.5, and GOLD 4.1 programs. The results of qRT-PCR revealed significant (p?<?0.05) upregulation of NOD1 and RICK expression. Molecular docking revealed that the amino acid residues at LRR1–2, LRR3–7, and LRR8–9 could be involved in poly I:C, LPS, and iE-DAP binding, respectively. In fish, this is the first report describing the 3D structure of NOD1-LRR and its critical ligand-binding motifs. 相似文献