Corrosion behaviour of porous Ni-free Ti-based bulk metallic glass produced by spark plasma sintering in Hanks' solution

Porous bulk metallic glasses (BMGs) are promising biomedical materials to be used for surgical implants. Here we report on successful formation of porous Ni-free Ti-based BMGs with a diameter exceeding 15 mm by spark plasma sintering the mixture of the gas-atomized Ti-based (Ti₄₅Zr₁₀Cu₃₁Pd₁₀Sn₄) glassy alloy powder and solid salt powder, followed by leaching treatment into water to eliminate the salt phase. Corrosion behaviour of the produced porous Ti-based BMGs was investigated in Hanks' solution. The potentiodynamic polarization curves showed that the anodic current density in the porous Ti-based BMGs slowly increased during anodic polarization, suggesting the crevice corrosion.     

Consolidation grouting technology for fire prevention in mined‐out areas of working face with large inclined angle and its application

The phenomenon of linear flow of slurry in mined‐out areas of working face with large inclined angle is a crucial issue that hinders grouting for fire prevention. The traditional way of grouting exerts a poor effect on inhibiting coal spontaneous combustion, so it is in urgent need of a suitable grouting technology for fire prevention in mined‐out areas with large inclined angle working face. This paper brings up the consolidation grouting method for fire prevention for the first time and conducts a systematic study on the flow characteristics of slurry and sedimentation characteristics of slurry in mined‐out areas with large inclined angle working face. Consolidation slurry materials and their ratio are optimized by experiments. Test platform has been established, and effectiveness of the consolidation grouting for fire prevention has been simulated. The results show that settling velocity of yellow mud increases at first and then decreases as the concentration of consolidation slurry materials ascends. The optimum mass concentration is 0.2%–0.8%. The flow speed of mud is greatly reduced by laying consolidation slurry materials (The decreasing range is approaching 50%). The retention of yellow mud in mined‐out areas has significantly increased. Finally, technology in working site has been developed; meanwhile, compressed air and spray between frames have been used during the period of working face, and the consolidated way of expansion bags in wood crib to lay consolidation slurry materials has been adopted during the period of stopping work. Field application shows that CO concentration at upper corner decreases significantly and eliminates signs of spontaneous combustion. Besides, the flowing water becomes clearer, and effectiveness of the consolidation grouting is remarkable after laying consolidation slurry material band. Research results can provide theoretical guidance to technology for fire hazard prevention in mined‐out areas with large inclined angle. Copyright © 2016 John Wiley & Sons, Ltd.     

碳纤维新技术在桥梁加固工程中的应用

通过介绍碳纤维技术在国内外的发展现状,阐述了碳纤维在桥梁修复加固工程的原理及施工中应注意的要点,最后说明了将碳纤维技术应用于桥梁加固修复有待解决的几个问题,以促进桥梁加固技术的发展。     

灌阳县新街乡土地整治项目土地平整设计

根据灌阳县新街乡土地整治项目的基本情况,介绍了土地平整思路、设计原则及要点,总结经验,指出土地平整中应注意的一些问题,为类似工程的设计提供参考。     

Approximate solutions for the ignition of a solid as a function of the Biot number

The ignition of a finite planar 1‐dimensional solid is addressed for constant applied radiant heat flux. An ignition temperature criterion is used, with constant properties, and linearized reradiation. An approximate integral analysis leads to analytic formulas to predict the ignition time in terms of Biot (Bi) number and heat flux. The accuracy of the integral solution is found to be good compared to the exact infinite series solution for the conduction equation. The integral model is then used to assess the accuracy of common ideal thick and thin formulas for ignition. There is a domain of heat flux and Bi where the ideal formulas are not accurate. An example is given where the integral model is accurately applied to ignition data to illustrate the range where the ideal formula is not accurate.     

基于CPTU测试的高速公路改扩建新老地基土工程特性评价研究

软土地基上进行高速公路扩建项目面临着极大的挑战,必须对新老地基土体的工程特性进行全面的评价。传统室内试验方法会对土体产生扰动,而且时间长、成本大。孔压静力触探(CPTU)技术作为一种新型的原位测试方法,可以测试锥尖阻力、侧壁摩阻力与孔隙水压力等参数,而且具有多功能、连续性、高精度等优点,在国外得到广泛的应用。采用多功能CPTU技术对京沪高速公路扩建工程新老地基土体进行原位测试,基于承载力理论与孔穴扩张理论分别解译了新老地基土体的应力历史、变形与固结特性参数。研究发现:该方法可以更准确地确定软土层的分布、厚度和深度,可为进一步分析新老路基差异沉降的计算提供科学依据,更好地指导路基拼接相互作用与地基处理的设计和施工。     

三网融合给广播电视网络带来的机遇与挑战

阐述了三网融合的起源和意义,介绍了三网融合的路径,分析了三网融合给广播电视网络带来的机遇和挑战,并提出相应策略。     

A case study in evaluating the status of consolidation of a soft soil deposit by incomplete piezocone dissipation tests using laboratory and field data

By using the piezocone penetration test (PCPT or CPTu), one can develop not only a better understanding of the soil stratification, but also an understanding of soil behavior parameters related to soil compressibility, as well as soil strength. This paper describes a case study that utilizes incomplete piezocone dissipation test to estimate status of consolidation of a soil deposit. Incomplete pore pressure dissipation record of PCPT is extrapolated on an inverse time scale (1/t method) to estimate the “in situ” pore pressure and “residual excess” pore pressure. No case study has been reported in open literature where this methodology has been utilized to estimate the status of consolidation of the soil deposit. In this paper, the 1/t method was verified using dissipation data from rigorous calibration chamber tests and field test data.     

斧子口水利枢纽大坝基础处理

介绍了桂林市斧子口水利枢纽的工程概况及坝址的工程地质情况,根据大坝基础地质条件,提出了斧子口水利枢纽大坝基础处理的目的和要求,论述了大坝基础的处理方案。     

道路桥梁的病害情况分析及加固技术研究

为减少道路桥梁事故的发生,分析了道路桥梁常见的病害类型,针对各种病害情况进行了原因分析,重点研究了道路桥梁结构加固技术,以期为道路桥梁的加固技术和防治病害的发生提供参考。