Experimental study on impact absorbing performance of motorcycle helmets

The regulation regarding motorcycle helmets to protect the head from impacts has been amended recently. In Europe, the Head Injury Criteria (HIC), which is more relevant to indicate the probability of death than the limitation of maximum acceleration, has been adopted. An experimental study has been conducted following the procedure of the new European regulation, by changing various helmet structural parameters such as the lamination and the bulk density of the shell, and the liner, to investigate the ability of the helmet to protect the head from injuries. The maximum acceleration and HIC were measured. Experimental data have been analyzed with respect to varying lamination of shells and weight of liners. The HIC was found to be improved by reducing the bulk density of the liner and the number of laminations of a shell, and by increasing the loading area of the headform.     

高炉炉壳整体应力的计算

针对高炉炉壳各种复杂的开孔及受力情况，考虑作用在高炉炉壳上的各种负荷，推导出相应的应力计算公式，针对宝钢3号高炉投产初期及当前状态，将3号高炉有关数据带入相应的计算公式，计算得到3号高炉各段炉壳上的应力值。     

Platinum Nanoparticles Anchored on TiO2/C Nanowires as a High Performance Catalyst for Hydrogen Peroxide Eletroreduction

In this paper, we employed the as‐prepared TiO₂/C core/shell nanoarrays (TiO₂/C) obtained by a facile thermal evaporation method as a three‐dimensional (3D) architecture to support Pt nanoparticles through an optimized electrodeposition process. The morphology and structure of the as‐prepared electrode are characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Its catalytic performance towards H₂O₂ electroreduction in basic medium is evaluated by linear sweep voltammetry (LSV) and chronoamperometry (CV). Results revealed that the electrode exhibits significantly high catalytic activity. The current density reached –0.172 A cm⁻² in 1 mol dm⁻³ NaOH and 0.5 mol dm⁻³ H₂O₂ at –1.1 V (vs. Ag/AgCl). This high performance might be due to the 3D electrode architecture inheriting the high electronic conductivity from carbon shell and providing a short pathway for the ion diffusion, and the using of Pt owning an excellent catalytic activity.     

Shell粉煤气化技术应用综述

简要介绍Shell粉煤气化技术特点和发展历程,对Shell粉煤气化技术工业应用中所出现的问题进行系统说明和分析,提出在工业应用中应注意的问题及措施建议。     

固定管板式换热器热处理有关问题的探讨

本文介绍了设计换热器时,对于壳程及管程进行热处理的一些问题,并提出了相应的解决方法。     

Chemical composition and structure of the shell of fly ash non-perforated cenospheres produced from the combustion of the Kuznetsk coal (Russia)

The relationship between the composition and structure of the shell of low-density non-perforated cenospheres of fly ashes from the combustion of coal from the Kuznetsk Basin (Russia) at temperatures of 1500 and 1650 °C has been investigated. Narrow fractions of cenospheres of constant composition have been separated from concentrates with the use of the technological scheme including stages of hydrodynamic gravitational separation, grain-size classification, and magnetic separation. It has been established that the concentrations of the major components of the chemical composition of the products obtained are related by linear regression equations. In particular, the aluminosilicate composition of the non-perforated cenospheres with a low Fe₂O₃ concentration (2.5-3.5 wt.%) is described by two general regression equations [SiO₂] = 80 − 0.7·[Al₂O₃] and SiO₂/Al₂O₃ = 5.54 − 0.12·[Al₂O₃] with correlation coefficients of −0.98 and −0.99, respectively. In this case, narrow fractions of products with different Fe₂O₃ contents are characterized by nearly constant SiO₂/Al₂O₃ ratios. The shell structure has been investigated using scanning electron microscopy. It has been revealed that the outer and inner surfaces of globules are covered by a film with a thickness of 30-50 nm. The surface of magnetic cenospheres contains heterogeneous regions with extended linear ferrospinel aggregates of crystallites with sizes ranging from 50 to 1000 nm. It has been shown that the size of globules and the thickness and porosity of the shell in each series depend on the composition of the melt from which they are formed and on its viscosity. Nonmagnetic cenospheres are formed from the high-silica K-Al-Si melt with the SiO₂/Al₂O₃ ratio varying over a wide range (1.6-3.6). Narrow fractions of magnetic cenospheres formed at low temperatures (1500 °C) are characterized by nearly constant SiO₂/Al₂O₃ ratios. Globules of this type are formed from two immiscible high-silica K-Al-Si and Fe-Al-Si melts.     

K8-11和QDB-04型变换催化剂在Shell粉煤气化制甲醇装置上的应用

介绍了K8-11和QDB-04型两种变换催化剂在Shell粉煤气化制甲醇装置上的使用情况,并介绍了试车过程中遇到的问题。运行结果表明,两种催化剂具有强度高、稳定性好、起活温度低、活性稳定性好、抗工况波动能力较强等优点,合理搭配使用这两种催化剂能适应较高汽气比、较高CO含量和较高压力的工况条件。     

浅谈壳牌气化炉煤烧嘴的安装

壳牌气化炉烧嘴系统在气化炉的开车和运行中极其重要,具有安装位置特殊、装配精度要求高的特点.介绍了壳牌气化炉烧嘴系统的组成,详细叙述了煤烧嘴的安装步骤及注意事项.     

Shell炉煤粉锁斗充压程序改进

介绍了Shell炉煤粉锁斗充压程序,分析了V1204加压程序在运行过程中存在的不足,并针对性地提出了一些改进措施。     

壳牌煤气化装置飞灰储罐锁斗阀技术改造

分析了飞灰锁斗控制阀出现故障的原因;提出了消除阀座加工误差、修复气缸力矩传递轴、增加阀座防尘装置的技改方案;结果表明,改进后阀门使用周期从原来的几天延长到几个月有以上。