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Both finite element models and multi-body models of human head-neck complex had been widely used in neck injuries analysis, as the former could be used to generate detailed stress strain information and the later could generate dynamic responses with high efficiency. Sometimes, detailed stress and strain information were hoped to be obtained more efficiently, but current methods were not effective enough when they were used to analyze responses of human head neck complex to long duration undulate accelerations. In this paper, a two-step procedure for ‘parallel’ development and ‘sequential’ usage of a pair of human head neck models was discussed. The pair of models contained a finite element model and a multi-body model, which were developed based on the coupling ‘parallel’ procedure using the same bio-realistic geometry. After being validated using available data, the pair of human neck models were applied to analyze biomechanical responses of pilot’s neck during arrested landing operation according to the ‘sequential’ procedure, because typical sustained undulate accelerations usually appeared during such processes. The results, including both kinematic and detailed biomechanical responses of human head-neck complex, were obtained with preferable efficiency. This research provided an effective way for biomechanical analysis of human head neck responses to sustained undulate accelerations. [ABSTRACT FROM AUTHOR]

Li2MnO3 based layered Li-rich materials as promising cathode candidates of Li ion batteries (LIBs) have attracted much recent attention mainly owing to their superior high specific capacity and high working voltage. To date, although researchers have put much effort to this family of materials, there are still a number of issues under debates in the fundamental understanding of the crystal structures and the electrochemical reaction mechanisms, before the materials can be ready for practical applications. In this review article, we address the recent progress of this group of Li-rich cathode materials with a good hope to better understanding of the relationships among composition, crystal structure and electrochemical reaction mechanisms. In addition, the use of advanced microscopic characterisation and the strategies of novel material designs will also be discussed for better cathode design for LIBs. [ABSTRACT FROM AUTHOR]

Hot deformation behaviour of 40Cr has been studied using processing map and microstructural observations. The material was deformed by compression at temperature from 750 to 1050°C and strain rate from 0·01 to 10 s−1. Based on the flow stress data, strain rate sensitivity index, power dissipation efficiency and instability parameter were evaluated. Processing maps were constructed for strain of 0·6. A domain of dynamic recrystallisation was identified at temperature from 900 to 1050°C and strain rate from 0·01 to 10 s−1. The optimum temperature and strain rate for 40Cr were 900°C and 0·1 s−1 respectively, whose efficiency was 30%. Owing to the dynamic recovery of 40Cr at temperature from 750 to 850°C and strain rate from 0·01 to 10 s−1, and the flow localisation at strain rates higher than 0·1 s−1 and temperature from 950 to 1050°C, the conditions mentioned above should be avoided during processing. [ABSTRACT FROM AUTHOR]

Hot deformation behaviour of 40Cr was investigated by conducting hot compression tests at the temperature range of 750–1050°C and the strain rate range of 0·01–10 s−1 on a Gleeble 1500 thermal mechanics simulator. Most true stress–strain curves show that the flow stress increases until a peak value and then decreases with the increasing of the strain, which ends up with a stationary stage. Further microstructural observation confirms the occurrence of dynamic recrystallisation behaviour of 40Cr. The experimental data were used to develop a constitutive equation on the basis of the Arrhenius equation. In the constitutive equation, the effect of strain on deformation behaviour is incorporated, and the flow stress correction parameters p1, p2, p3, p4 and p5 are represented by the Zener–Holloman parameter. The flow stresses predicted by the constitutive equation show good agreement with the experimental stresses, with the mean error <4·86%. [ABSTRACT FROM AUTHOR]

Coal pitch water slurry is prepared by coal pitch powder, dispersants, and deionized water. Using two kinds of particle size distribution powder, influence of the amount of dispersants and slurry content on the slurry ability of coal pitch water slurry is studied. The results show that at the same amount of dispersants, the apparent viscosity of coal pitch water slurry increases with increasing the slurry content. On the whole, at the same amount of dispersants and slurry content, the apparent viscosity of coal pitch water slurry prepared by powder of gradation 2 is less than that of gradation 1. [ABSTRACT FROM AUTHOR]