The energy absorption characteristic of steel tube material and concrete material is an important indicator to reflect the impact resistance of circular concrete-filled steel tubular (CFST) members. In order to efficiently simulate the material energy absorption of the steel tube and concrete under lateral impact, a nonlinear finite element model considering the material strain rate of the circular CFST member was established and validated based on the drop weight tests. Then, the energy absorption mechanism of circular CFST members subjected to lateral impact was investigated including the revelation of the energy absorption process and the determination of the energy absorption distribution for the steel tube material and concrete material, which are obtained respectively based on the comprehensive analysis of dynamic response and innovative establishment of the segmented numerical model. In addition, the influence of impact momentum on energy absorption process and the effect of impact location on energy absorption distribution are further carried out. The observations of this investigation can provide reference for the anti-impact design and damage reinforcement of circular CFST members subjected to lateral impact.
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http://dx.doi.org/10.3390/ma14164652 | DOI Listing |
Commun Chem
January 2025
Institute of Chemical Sciences, Heriot-Watt University, Edinburgh, UK.
Various photoactive molecules contain motifs built on aza-aromatic heterocycles, although a detailed understanding of the excited state photophysics and photochemistry in such systems is not fully developed. To help address this issue, the non-adiabatic dynamics operating in azanaphthalenes under hexane solvation was studied following 267 nm excitation using ultrafast transient absorption spectroscopy. Specifically, the species quinoline, isoquinoline, quinazoline, quinoxaline, 1,6-naphthyridine, and 1,8-naphthyridine were investigated, providing a systematic variation in the relative positioning of nitrogen heteroatom centres within a bicyclic aromatic structure.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Osaka University Graduate School of Engineering Science School of Engineering Science: Osaka Daigaku Daigakuin Kiso Kogaku Kenkyuka Kiso Kogakubu, Department of Materials Engineering Science, Machikaneyama 1-3, 560-8531, Toyonaka, JAPAN.
An overcrowded ethylene composed of electron-donating anion, naphthoxide, and electron-accepting cation, acridinium, has been synthesized. It is in equilibrium between a folded conformer having a smaller permanent dipole moment with visible light absorption and a twisted conformer having a larger permanent dipole moment with NIR light absorption. The overcrowded ethylene shows multiple NIR chromisms, such as solvatochromism, thermochromism, mechanochromism, vapochromism, halochromism, and amphoteric electrochromisms, which are caused by the conformational change between folded and twisted conformers or by controlling the energy difference between the HOMO of the donor moiety and the LUMO of the acceptor moiety.
View Article and Find Full Text PDFInorg Chem
January 2025
Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada.
Pendant organic chromophores have been used to improve the photocatalytic performance of many metal-based photosensitizers, particularly in first-row metals, by increasing π conjugation in ligands and lowering the energy of the photoactive absorption band. Using a combination of spectroscopic studies and computational modeling, we rationalize the excited state dynamics of a Co(III) complex containing pendant pyrene moieties, , where = 1,1'-(4-(pyren-1-yl)pyridine-2,6-diyl)bis(3-methyl-1-imidazol-3-ium). displays higher visible absorptivity, and blue luminescence from pyrene singlet excited states compared with [ = 1,1'-(pyridine-2,6-diyl)bis(3-methyl-1-imidazol-3-ium)] in which the pyrene moiety is absent.
View Article and Find Full Text PDFAcc Chem Res
January 2025
Centre for Computational Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom.
ConspectusPhotochemical reactions have always been the source of a great deal of mystery. While classified as a type of chemical reaction, no doubts are allowed that the general tenets of ground-state chemistry do not directly apply to photochemical reactions. For a typical chemical reaction, understanding the critical points of the ground-state potential (free) energy surface and embedding them in a thermodynamics framework is often enough to infer reaction yields or characteristic time scales.
View Article and Find Full Text PDFAppl Biochem Biotechnol
January 2025
Centre for Applied Research, Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences (SIMATS), Thandalam, Chennai, Tamil Nadu, 602105, India.
Nelumbo nucifera, an aquatic crop cultivated throughout Asian countries, belongs to the Nelumbonaceae family and has been widely used in traditional medicines with key pharmacological activities such as anti-viral, antipyretic, antioxidant, anti-steroid, anti-inflammatory, anti-arrhythmia, anti-obesity, and anti-aging properties. The present study aims to explore and assess the phytochemical composition, GC-MS profiling, antioxidant efficacy, and the major phytoconstituent phytol subjected to theoretical spectroscopic characterization using the DFT method. The phytochemical profiling of N.
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