排序方式: 共有45条查询结果,搜索用时 0 毫秒
41.
R. M. O'Higgins G. S. Padhi M. A. McCarthy C. T. McCarthy 《Mechanics of Composite Materials》2004,40(4):269-278
Open-hole tension tests are a part of the qualification process for composite parts that need to be joined to other parts in aircraft structures [1]. With each new material, a new set of tests is required. To reduce costs, it is desirable to develop analysis tools for the prediction of damage and failure in such tests, so that the amount of testing can be reduced and predictions can be made about material behaviour early in the design process. In this paper, an experimental and numerical study is presented on the notched (open-hole) strength of high-strength carbon/epoxy composites (HTA/6376). Open-hole tension tests have been performed on specimens with three different lay-ups — quasi-isotropic, zero-dominated, and cross-ply — in accordance with procedures in available standards. The data observed are being used to develop several methods for predicting the notched strength, and results from one such method using a progressive damage analysis are presented with comparisons with experiments. The predictions of specimen stiffness and failure load were found to agree well with experiments. To gain insight into the failure process, damage progression maps are shown. 相似文献
42.
Visweswara Rao Garimella Sridhar Yeleswarapu Hela Pamidipati Gayatri Padhi Trilochan Anipindi Nageswara Rao 《Transition Metal Chemistry》1999,24(5):566-570
The kinetics of substitution of Fe(tptz)2+2 by 2,2-bipyridine and 1,10-phenanthroline have been investigated in acetate buffers in the 3.6–5.6pH range employing stopped-flow spectrophotometry. These reactions are very fast and complete within 5s. The rate of substitution is linearly dependent on [phen] and [bpy]2, and increases with the increase in pH. Suitable mechanisms have been proposed involving the unprotonated form of the entering ligand, viz. bipyridine/phenanthroline as the reactive species. The pKa values of bipyridine and phenanthroline, determined from the kinetic data, are in agreement with the literature values. It is concluded that the substitutions of iron(II)-diimine complexes also occur by an associative mechanism. 相似文献
43.
44.
45.
Srichandan Padhi Marco Masi Sujogya K. Panda Walter Luyten Alessio Cimmino 《Natural product research》2020,34(18):2573-2580
AbstractA new 6-benzyl-γ-pyrone (1), named aspergyllone was isolated from the culture filtrates of an endolichenic fungus Aspergillus niger Tiegh, obtained from lichen thallus Parmotrema ravum (Krog & Swinscow) Serus, collected in India. 1 was isolated for the first time from an endolichenic fungus together with six other known metabolites identified as aurasperones A (2) and D (3), asperpyrone A (4), fonsecinone A (5), carbonarone A (6) and pyrophen (7). The compounds were tested against a panel of human, plant, food borne and fish pathogens. Aspergyllone showed strong selective antifungal activity against Candida parapsilosis (Ashford) Langeron & Talice, with an IC50 of 52?µg/mL. Aurasperone A and pyrophen showed moderate to strong antimicrobial activity inhibiting seven different test pathogens, being pyrophen active with IC50 ranging from 35 to 97?µg/mL. 相似文献