Influences of the inner diameter of the solid shielding tube on the characteristics of the radio-frequency cold atmospheric plasma jet

Active control of the local environment of the cold atmospheric plasma (CAP) jet is of great importance in actual applications since the CAP operates in an open atmosphere with the inevitable entrainment of the surrounding cold air. In this paper, the solid shielding effects of the cylindrical quartz tubes with different inner diameters on the characteristics of the CAP jets driven by a radio-frequency (RF) power supply are studied experimentally. The experimental results show that the total length of the shielded plasma jet can be increased significantly by an appropriate combination of the quartz tube inner diameter and that of the plasma generator nozzle exit with other parameters being unchanged. This phenomenon may be qualitatively attributed to the loss of diffusion of the charged particles in the radial direction under different inner diameters of the quartz tubes. Compared with the plasma free jet, the plasma shielding jet is produced with optimized parameters including longer plasma jet length, higher concentrations of chemically reactive species, higher rotational, vibrational, and electron excitation temperatures when the inner diameters of the solid shielding tube and the generator nozzle exit are the same. A maximum plasma jet length of 52.0 cm is obtained in contrast to that of 5.0 cm of the plasma free jet in this study. The experimental results indicate that the solid shielding effect provides a new method for the active control of the local environment of the RF-CAP jet operating in an open atmosphere.     

海月构造带东三段滩坝砂分布及成藏主控因素分析

辽河滩海地区海月构造带东三段沉积期,三角洲前缘砂体受湖岸流和波浪的改造,形成了一系列滩坝砂沉积,细分为滩砂和坝砂,水动力强则形成坝砂,水动力弱则形成滩砂;滩坝砂平行于湖岸线呈带状分布,易于形成岩性圈闭。滩坝砂受砂体发育规模、储层物性、断裂输导体系及封堵性等多种因素控制,在滩坝砂较为发育的东三下段,靠近海南断层、盖州滩断层且封堵条件优越的滩坝砂最易于成藏。     

Eco-driving: the role of feedback in reducing emissions from everyday driving behaviours

Eco-driving has been proposed as an approach to significantly reduce greenhouse gas emissions arising from personal automobile use. Eco-driving is the adoption of a measured driving style, minimising unnecessary breaking and aggressive acceleration. Eco-driving can be seen as a low cost and immediate approach to emission reduction as it involves the modification of drivers’ behaviours as opposed to the development and implementation of newer, more efficient technology. Despite the proposed benefits of eco-driving, numerous challenges are faced in order to encourage the adoption of these behaviours and maintain them long term. This narrative review presents the concept of eco-driving, with a focus on the long-term maintenance of these behaviours, including training programmes and feedback devices. It is clear within current literature that, despite the economic and environmental benefits of adopting eco-driving, drivers require feedback on their actions in order to promote long-term, behavioural, change.     

Unconditional stability and error estimates of the modified characteristics FEMs for the time-dependent incompressible MHD equations

This paper focuses on the unconditional stability and convergence of characteristics type methods for the time-dependent incompressible MHD equations. For this purpose, we introduce a new characteristics time-discrete system. The optimal error estimates in $L^2$ and $H^1$ norms for the typical modified characteristics finite element method unconditionally can be deduced, while the whole previous works require certain time-step restrictions. Some numerical experiments document performance of the characteristics type methods for the time-dependent incompressible MHD equations.     

The Art of Masonry

Brick masonry is not only a question of building physics, building construction and durability, i.e. sustainability, but has much to do with aesthetics and making sense, which may have been forgotten in modern architecture with its absolute lack of décor. Masonry as an art form has been scarce since the era of brick expressionism. Recently, there have been some exceptions – and thoroughly welcome. The ”Fjordenhus“ in Vejle, Denmark, is an astonishing example.     

In‐plane shear damage behaviours of 2D needled C/SiC composites

Understanding the in‐plane shear behaviour of composites is essential to establish the design basis for practical applications. This study aims to investigate the shear damage behaviours of 2D needled C/SiC composites by various characterization techniques. The effect of layer arrangement on shear modulus and strength was discussed via shear stress‐strain responses. The shear strain field evolution and uniformity variation were studied by digital image correlation. It shows that the uniformity of shear strain field changes with the shear load, and the shear strain field evolution consist of 5 stages. The electrical resistivity measurement results indicate that structural deformation and damage evolution caused the electrical resistivity change. Furthermore, the damage evolution has a double effect on the electrical resistivity variation. The acoustic emission monitoring shows that the shear damage evolution is a 3‐stage nonlinear process before failure. The shear damages were categorized via acoustic characteristics. Besides, the postfailure behaviours were also discussed in this study.     

径向弹簧蓄能密封结构最大接触应力的有限元分析

为研究径向弹簧蓄能密封结构的密封特性，针对典型径向弹簧蓄能密封结构，分析其密封机制以及O形弯曲金属螺旋弹簧的弹性特性；采用ANSYS有限元分析软件，建立典型弹簧蓄能密封结构的非线性有限元分析模型，对弹簧蓄能密封圈在不同压缩率、不同介质压力下的接触应力进行分析，研究在多种工况下最大接触应力的变化情况。结果表明：压缩率保持不变时，最大接触应力随着介质压力的增大而增大；介质压力保持不变时，随着压缩率的增大，最大接触应力先增大再减小。对压缩率、介质压力与最大接触应力的关系进行曲线拟合，可用于指导弹簧蓄能密封结构的精确设计。     

基于CSC方法的钢铁行业节能减排技术潜力分析

为了研究中国钢铁行业的节能减排潜力，以35项钢铁行业先进节能减排技术为研究对象，建立节能供应曲线(Conservation Supply Curve，简称CSC)模型，分析影响钢铁行业的节能减排收益、成本效益以及钢铁生产流程工序层面的节能减排潜力因素。结果表明，这35项技术全部应用可实现3.01 GJ/t的节能量以及398.22 kg/t的CO2减排量。将结果与第十三个五年计划推广技术作对比，在当前情况下，约有50%的推广技术并不符合成本效益；运用CSC模型进行了钢铁生产流程工序层面的节能减排潜力研究，得到各个工序的节能量和减排量，并据此分析了各项技术未来的发展趋势和应用前景。