Precast concrete walls with unbonded post-tensioning provide a simple self-centering system. Yet, its application in seismic regions is not permitted as it is assumed to have no energy dissipation through a hysteretic mechanism. These walls, however, dissipate energy imparted to them because of the wall impacting the foundation during rocking and limited hysteretic action resulting from concrete nonlinearity. The energy dissipated due to rocking was ignored in previous experimental studies because they were conducted primarily using quasi-static loading. Relying only on limited energy dissipation, a shake table study was conducted on four single rocking walls (SRWs) using multiple-level earthquake input motions. All walls generally performed satisfactorily up to the design-level earthquakes when their performance was assessed in terms of the maximum transient drift, maximum absolute acceleration, and residual drift. However, for the maximum considered earthquakes, the walls experienced peak lateral drifts greater than the permissible limits. Combining the experimental results with an analytical investigation, it is shown that SRWs can be designed as earthquake force-resisting elements to produce satisfactory performance under design-level and higher-intensity earthquake motions. a The SA method; using design/measured parameters. b SRW1m, SRW3m, and SRW4m; after 50% loss in the initial PT force of SRW1, SRW3, and SRW4. SA, Simplified Analysis. 756 M. NAZARI, S. SRITHARAN AND S. AALETI Figure 7. Impact of armoring the wall base using a steel channel as evidenced for EQ-IV level motions (1 m = 3.28 ft). [Colour figure can be viewed at wileyonlinelibrary.com] Figure 8. Global and local behavior of SRW2 using experimental data and the Simplified Analysis (SA) method (1 m = 3.28 ft; 1 kip = 4.45 kN). [Colour figure can be viewed at wileyonlinelibrary.com] Figure 9. Influence of initial prestress force on the global behavior of test walls (1 m = 3.28 ft; 1 kip = 4.45 kN). [Colour figure can be viewed at wileyonlinelibrary.com]
The objective of this study was to fabricate betanin nanoliposomes incorporated gelatin/chitosan nanofiber/ZnO nanoparticles bionanocomposite film (G/CH NF/ZnO NPs/B NLPs) and investigate its effects on the preservation of fresh beef. The scanning electron microscopy image of nanocomposite film displayed a good inter-connective porous morphology. Fourier transform infrared and X-ray diffraction analysis confirmed the formation of new hydrogen bonds and enhanced crystallinity through the addition of CH NF, ZnO NPs, and B NLPs. The G/CH NF/ZnO NPs/B NLPs film exhibited satisfactory mechanical properties and high surface hydrophobicity (water contact angle = 92.49 ± 3.71°). The incorporation of ZnO NPs and B NLPs in the nanocomposite film provided high antibacterial activity and DPPH inhibition activity (53.02 ± 3.26%). The growth of inoculated bacteria, lipid oxidation, and the changes in the pH and color quality of the beef samples were controlled by packaging with the fabricated film. In conclusion, the G/CH NF/ZnO NPs/B NLPs nanocomposite has a high potential for meat preservation
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