In this investigation, a curved beam element is developed for the analysis of large deformation of flexible multi-body systems using the absolute nodal coordinate formulation. In the existing beam element in this formulation, because the elastic forces are defined using the Green -Lagrange strain tensor as a volume element, locking phenomenon associated with the shear and cross-section deformation leads to erroneously stiffer bending characteristics. In order to circumvent this drawback, the Hellinger-Reissner variational principle is applied to modify the shear stress distribution, whereas the assumed strain method is employed to alleviate the locking associated with the cross-section deformation. The consistent tangent stiffness matrices are derived for the curved beam element and used with implicit integration methods. Numerical examples are presented in order to demonstrate the performance of the curved beam element developed in this investigation.

Calcium silicate hydrate (C-S-H) is a dominant hydration product of cementitious materials. Therefore, its chemical composition and physical properties affect the performance of concrete. The purpose of this study is to investigate the chemical composition (CaO/SiO 2 molar ratio (Ca/Si ratio), and H 2 O/SiO 2 molar ratio (H 2 O/Si ratio)) and physical properties, such as density and specific surface area, of C-S-H. These factors are measured using synthesized C-S-H samples and C-S-H generated from various cementitious materials. Experimental results show that the H 2 O/Si ratio of C-S-H is proportional to the Ca/Si ratio independent of the mix proportion, curing temperature and type of binder. The density and specific surface area of C-S-H are affected by its Ca/Si ratio. A linear relationship is observed between the Ca/Si ratio and density of C-S-H independent of the mix proportion, curing temperature and type of binder. An inversely proportional relationship is found between the Ca/Si ratio and specific surface area of C-S-H.

1,4-Rhodium migration occurs twice during the course of the rhodium-catalysed arylative ring-opening/spirocyclisation reaction of (3-arylcyclobutylidene)acetates with sodium tetraarylborates to afford ketones possessing a 1,1'-spirobiindane skeleton.

Increasing the performance of Pt-based electrocatalysts for the oxygen reduction reaction (ORR) is essential for the widespread commercialization of polymer electrolyte fuel cells. Here we show the synthesis of double-layer Pt nanosheets with a thickness of 0.5 nm via the topotactic reduction of 0.9 nm-thick single-layer PtOx nanosheets, which are exfoliated from a layered platinic acid (HyPtOx). The ORR activity of the Pt nanosheets is two times greater than that of conventionally used state-of-the-art 3 nm-sized Pt nanoparticles, which is attributed to their large electrochemically active surface area (124 m2 g−1). These Pt nanosheets show excellent potential in reducing the amount of Pt used by enhancing its ORR activity. Our results unveil strategies for designing advanced catalysts that are considerably superior to traditional nanoparticle systems, allowing Pt catalysts to operate at their full potential in areas such as fuel cells, rechargeable metal–air batteries, and fine chemical production.

In this investigation, a non-linear elastic ring tyre model is developed. The elastic deformation of the tyre belt is modelled using the finite element absolute nodal coordinate formulation that allows for describing large rotational motion and the non-linear inertia effects; the curved structure of the tyre belt; and moving boundary resulting from the tread and road interaction. Using a concept of elastic ring tyre models, the sidewall flexibility of a tyre is modelled using circumferential and radial springs and dampers defined between the belt and rim, while the tangential tyre force is modelled using friction elements defined at contact nodes defined within the curved belt elements. Numerical examples are presented in order to demonstrate the use of the flexible tyre model developed in this investigation. Good agreements are demonstrated in the tyre vibration characteristics obtained using the experiments and the proposed model. It is presented that the proposed tyre model can be used for assessing dynamic characteristics of tyres in high frequency ranges resulting from the interaction to uneven road surfaces.

R h o d i u m -C a t a l y z e d S i l y l a t i v e C y c l i z a t i o n o f A l k y n e s a n d 1 , 6 -D i y n e s

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