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81.
82.
Damage Assessment of Reinforced Concrete Structures Using Fractal Analysis of Residual Crack Patterns 总被引:1,自引:0,他引:1
A. Farhidzadeh E. Dehghan-Niri A. Moustafa S. Salamone A. Whittaker 《Experimental Mechanics》2013,53(9):1607-1619
Currently, assessing the performance and safety of reinforced concrete structures relies on routine-based visual inspection (VI). Cracks width measurements are commonly used as a convenient indicator of damage; however other factors, such as distribution and pattern of the cracks should be considered equally important in measuring the extent of damage present in the structure. As a result, condition assessed by VI is subjective in nature and depends on the experience, knowledge, expertise, and judgment of the inspector carrying out the assessment. A new approach based on the fractal analysis of residual crack patterns is proposed in this paper to assess the structural integrity of reinforced concrete elements. A new damage index is presented to quantitatively perform a damage classification. The methodology is validated through experimental studies on two large-scale reinforced concrete shear walls subjected to a displacement controlled reversed cyclic loading. Damage grades are also identified based on width of cracks and proposed damage index (DI). The results demonstrate a more accurate estimation of damage grades using DI. Furthermore, it is demonstrated that the DI can estimate the relative stiffness loss of the specimens with acceptable accuracy. 相似文献
83.
The copolymerization of itaconic anhydride (M1) with four different monomers (M2), namely: vinyl acetate, 2-chloro-ethyl acrylate, acrylonitrile, and styrene, was studied. Values of r1 and r2 were determined for copolymerizations in benzene and for two of these systems, namely those with vinyl acetate and 2-chloroethyl acrylate. Values of r1 and r2 were also determined for copolymerizations in tetra-hydrofuran. The value of ri ranged from 0.53 to 4.8, but it was always very much greater than r2. The Q-e values for itaconic anhydride in all the systems studied were also calculated and the average values for Q1 = 8.2, e1 = 1.45 were determined. 相似文献
84.
Saoud A. M. Metwally Thanaa A. Mohamed Osama S. Moustafa Yasser A. El-Ossaily 《Chemistry of Heterocyclic Compounds》2007,43(9):1131-1137
Reactions of 4-alkylidene(arylidene)-1-phenylpyrazolidine-3,5-dione with oxidizing (chromium trioxide/acetic acid) as well
as with reducing (sodium borohydride/methanol) agents were carried out. Phenylhydrazine reacted with 4-arylidene-1-phenylpyrazolidine-3,5-diones
via fission of exo C=C bond to give 1-phenylpyrazolidine-3,5-dione and the corresponding aryl hydrazones.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1335–1341, September, 2007. 相似文献
85.
The influence of the Cu‐content in the quaternary compounds CuxAg1‐xInTe2 (0 ≤ x ≤1) on the structural properties of the bulk material was discussed. Bulk ingot materials of CuxAg1‐xInTe2 solid solutions (x = 0.0, 0.25, 0.50, 0.75 and 1.0) have been synthesized by fusion of the constituent elements in the stoichiometric ratios in vacuum‐sealed silica tubes. The materials compositions were confirmed by using energy dispersive analysis of X‐rays (EDAX). X‐ray powder diffraction measurements were performed for all the prepared samples at 300 K in step scanning mode. The analysis of X‐ray data has indicated that the crystal structure of the prepared materials with different compositions is single‐phase polycrystalline materials corresponding to the tetragonal chalcopyrite structure with space group I 2d. The crystal structural parameters were refined by Rietveld method using the Full Prof program. The refined lattice constants (a and c), anion positional parameter, u, and the determined bond distances and angles were found to vary with composition, x, attaining zero tetragonal distortion at x ≈ 0.75, which corresponds to an ideal tetragonal unit cell. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
86.
Mamdouh M. Shawki Alaa El Sadieque Seham Elabd Maisa E. Moustafa 《Molecules (Basel, Switzerland)》2022,27(14)
Cancer remains a leading cause of death worldwide, despite extraordinary progress. So, new cancer treatment modalities are needed. Tumor-treating fields (TTFs) use low-intensity, intermediate-frequency alternating electric fields with reported cancer anti-mitotic properties. Moreover, nanomedicine is a promising therapy option for cancer. Numerous cancer types have been treated with nanoparticles, but zinc oxide nanoparticles (ZnO NPs) exhibit biocompatibility. Here, we investigate the activity of TTFs, a sub-lethal dose of ZnO NPs, and their combination on hepatocellular carcinoma (HepG2), the colorectal cancer cell line (HT-29), and breast cancer cell lines (MCF-7). The lethal effect of different ZnO NPs concentrations was assessed by sulforhodamine B sodium salt assay (SRB). The cell death percent was determined by flow cytometer, the genotoxicity was evaluated by comet assay, and the total antioxidant capacity was chemically measured. Our results show that TTFs alone cause cell death of 14, 8, and 17% of HepG2, HT-29, and MCF-7, respectively; 10 µg/mL ZnO NPs was the sub-lethal dose according to SRB results. The combination between TTFs and sub-lethal ZnO NPs increased the cell death to 29, 20, and 33% for HepG2, HT-29, and MCF-7, respectively, without reactive oxygen species increase. Increasing NPs potency using TTFs can be a novel technique in many biomedical applications. 相似文献
87.
Hassan A. El-Sayed Ahmed H. Moustafa Abd El-Fattah Z. Haikal 《Phosphorus, sulfur, and silicon and the related elements》2013,188(5):649-662
Abstract The reaction of 5-(2-methylthio)phenyl-1,2,4-triazole-3-thiol with glucosyl, galactosyl, lactosyl bromide, and peracetylated ribose under the conventional and microwave irradiation methods afforded the corresponding S-glycosides. Deacetylation of S-glycosides gave the corresponding deacetylated derivatives. Reaction of 5-(2-methylthio)phenyl-1,2,4-triazole-3-thiol with 4-acetoxybutyl bromide, 2-acetoxyethoxymethyl bromide, 3-chloropropanol, 1,3-dichloroopropan-2-ol, epichlorohydrin, allyl bromide, and propargayl bromide gave the corresponding S-acyclonucleosides, which were deacetylated to give the corresponding deacetylated compounds. All the newly synthesized compounds were characterized by the IR, 1H, 13C NMR, and elemental analyses. Some of these compounds were screened for their antiviral and antimicrobial activity. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the related elements to view the free supplemental file. 相似文献
88.
Hassan A. El-Sayed Ahmed H. Moustafa Esraa A. Abd El-Salam 《Journal of heterocyclic chemistry》2020,57(7):2738-2747
Study the synthesis and fluorescent properties of a new series of D-π-A fluorescent dyes based on nicotinonitrile and azobenzene is the main objective for this work. Reduction with Zn/HCl, diazotization with HCl/NaNO2, and coupling using catalytic NaOH or AcONa are simple applied methods. Where, nicotinonitrile 3 was synthesized via reduction of nitro derivative 1 followed by diazotization with HCl/NaNO2 in acetic acid. The formed benzene diazonium chloride was coupled with several activated phenols, aniline, and α-CH acids to yield the respective azo dyes 4-11 in moderate to good yield. Dyes 11a-d subjected to intermolecular cyclization with hydrazine hydrate resulted in pyrazole dyes 12-15 in moderate yield. Dyes containing pyrazole moiety or electron-withdrawing groups at the sixth position of pyridine nucleus exhibit stronger blue-green emission (λfl.max = 503, 507, 500, 501, 502, 493, and 514 nm) than that of the rest of compounds. 相似文献
89.
Moustafa T. Gabr Eman R. El-Bendary Nanting Ni Mona I. Shaaban Mohammed M. El-Kerdawy 《合成通讯》2013,43(22):2899-2911
AbstractNew isatin-β-thiocarbohydrazone hybrids 4-17 were designed relied on isatin scaffold to generate various analogs with expected antimicrobial activity. The new hybrids were estimated for antibacterial effectiveness over S. aureus, B. cereus and E. coli, and antifungal efficacy over C. albicans and A. fumigatus. Compound 14 evinced the highest efficacy over A. fumigatus and C. albicans. In addition, 5 and 12 showed eminent efficacy toward A. fumigatus, where compounds 4, 7, 9, 11, 13, 15 and 16 exhibited moderate activity over the same fungus. Moreover, 6 and 9 displayed moderate activity over C. albicans. The new compounds were also estimated for antiquorum-sensing effectiveness against C. violacium, where compound 17 showed interesting activity. In vitro cytotoxicity assay of the new analogs was done over Hela and COS-7 cancer cell lines. All analogs have IC50 values >50?μM toward both cell lines. 相似文献
90.