Mechanical properties and energy absorption capability of a new multi‐cell lattice honeycomb paperboard under out‐plane compression: Experimental and theoretical studies

Author(s):  
Kun Li ◽  
Jun Wang ◽  
Lixin Lu ◽  
Qinghua Qin ◽  
Junzhong Chen ◽  
...  
Author(s):  
Diego Villegas ◽  
William Dehlin ◽  
Tammy L. Haut Donahue

Menisci are fibrocartilagenous structures located between the femoral condyles and tibial plateau that aid in joint lubrication and stability in the knee joint. Previous experimental and theoretical studies have shown that the meniscal horn attachments, which serve as the transition from mensical fibrocartilage into subchondral bone, are important for proper meniscal function [1–3]. Meniscal attachments did not show significant differences in surface mechanical properties such as ultimate strain or moduli, however, there were significant differences in overall behavior of the anterior versus posterior attachments [4]. No significant differences in creep or stress relaxation properties were found between the different meniscal attachments [5].


2020 ◽  
Vol 315 ◽  
pp. 07002
Author(s):  
Zaur Galyautdinov ◽  
Oleg Kumpyak ◽  
Daud Galyautdinov

The formation of non-intersecting cracks in stress-strained ferroconcrete elements leads to separation of concrete strips between the cracks. The results of the experimental research indicate a significant decrease of the durability and deformability of the stress-strained concrete strips between cracks both under static and short-term dynamic loading. At the same time physico-mechanical properties depend on the straining deformations and rebars’ inclination angle towards the cracks. The existing theoretical and experimental results evaluate only the durability of the concrete strips between the cracks. The current paper presents the results of experimental and theoretical studies on the dynamic deformability of the stress-strained discs between the cracks. The statistic analysis of the experimental data is done; on the basis of the analysis we suggest the dependencies, characterizing the deformability of the concrete strips during the short-term dynamic load depending on the level of the straining deformations and rebars’ inclination angle towards the cracks.


2020 ◽  
Author(s):  
Thomas Louis-Goff ◽  
Huu Vinh Trinh ◽  
Eileen Chen ◽  
Arnold L. Rheingold ◽  
Christian Ehm ◽  
...  

A new, efficient, catalytic difluorocarbenation of olefins to give 1,1-difluorocyclopropanes is presented. The catalyst, an organobismuth complex, uses TMSCF<sub>3</sub> as a stoichiometric difluorocarbene source. We demonstrate both the viability and robustness of this reaction over a wide range of alkenes and alkynes, including electron-poor alkenes, to generate the corresponding 1,1-difluorocyclopropanes and 1,1-difluorocyclopropenes. Ease of catalyst recovery from the reaction mixture is another attractive feature of this method. In depth experimental and theoretical studies showed that the key difluorocarbene-generating step proceeds through a bismuth non-redox synchronous mechanism generating a highly reactive free CF<sub>2</sub> in an endergonic pre-equilibrium. It is the reversibility when generating the difluorocarbene that accounts for the high selectivity, while minimizing CF<sub>2</sub>-recombination side-reactions.


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