不锈钢表面阻氢涂层研究进展

不锈钢是高压氢系统的常用材料，在氢能储输技术中发挥重要作用，但高压氢环境引起的塑性降低、疲劳裂纹扩展速率加快等不锈钢氢脆问题，严重阻碍了氢能的产业化发展，在不锈钢材料表面制备阻氢涂层是解决不锈钢氢损伤问题的重要手段之一。本文首先综合介绍了典型涂层材料的应用特点及阻氢性能，探讨了制备工艺对涂层阻氢性能的影响、不同涂层材料的阻氢机理，并分析了涂层阻氢性能影响因素，之后总结了涂层阻氢性能评价方法及各种评价方法的优势与不足，并根据各种评价方法的技术特点，指出每种方法的适用范围。最后，基于阻氢涂层研究进展，文章提出以开发新型涂层结构为研究重点，同时加快新型涂层材料的探索，并重点关注涂层氢环境原位性能评价方法的研究。     

安规测试仪用于塑料制品探伤检测

该文介绍了传统的超声波、渗透和射线等绝缘体探伤方法,分析了它们的优缺点,针对其缺点,提出了用安规测试仪探伤塑料制品的方法。实验中,设置安规测试仪为拉弧停止,试验检测合格品的最高耐受电压,高压扫描塑料制品,筛选出不合格品。其过程简单、高效、快速、准确而且经济适用,可以通过改造测试探头适应不同的塑料制品,能取得不错的检测效果。     

Methodology for optimization of pouring variables using bottom pour for low masses of SS304 (<300 kg) in investment casting process (case study)

Bottom pour ladles with stopper rod systems are commonly used in the metal casting industry. However, stopper rod bottom-pouring systems have not yet been developed for the lower thermal masses of alloys typically used in the investment casting industry. Large thermal masses used with bottom pour systems are typically limited for ladles larger than 700 kg and to certain alloys with higher fluidity and longer solidification time like cast iron, aluminum alloys etc. In this study, bottom pour ladle designs and low thermal mass refractory systems have been developed and evaluated in production investment foundry trials with 300 kg pouring ladle. The ladles system and pouring practices used will be described along with the results from the pouring trials for SS304 that represents typical alloys used in Investment casting industries. Optimization of the variables used in an experimentation using Genetic algorithm is also explained.     

PREPARATION AND ELECTROCHEMICAL PROPERTIES OF NANOSCALE POROUS CARBON ELECTRODE MATERIALS BASED ON RICE PLANT SOOT

Supercapacitors are a kind of novel energy storage devices with long cycle stability and high power density. Electrode materials selection is one of the key factors that affect the properties of supercapacitors. Biomass-derived electrode materials – being low cost, renewable and environmentally friendly – are therefore attracting researchers’ attention. In this work, we adopted a simple process of carbonization and activation with rice plant soot, a common biomass material, as carbon source, and finally obtained the nanoscale porous carbon electrode (NPCE) materials. Then, the electrochemical properties of the as-prepared NPCE materials were tested in 6 M KOH, and the results indicated that the specific capacitance could reach 216?Fg^?1. Therefore, this low-cost, highly efficient technique is a significant milepost towards environmentally sustainable and commercially feasible fabrication of carbon electrode materials from biomass sources.     

Reliability of design approaches for axially loaded offshore piles and its consequences with respect to the North Sea

In the near future, several offshore wind farms are planned to be built in the North Sea. Therefore, jacket and tripod constructions with mainly axially loaded piles are suitable as support structures. The current design of axial bearing resistance of these piles leads to deviant results regarding the pile resistance when different design methods are adopted. Hence, a strong deviation regarding the required pile length must be addressed. The reliability of a design method can be evaluated based on a model error which describes the quality of the considered design method by comparing measured and predicted pile bearing resistances. However, only few pile load tests are reported with regard to the boundary conditions in the North Sea. This paper presents 6 large-scale axial pile load tests which were incorporated within a new model error approach for the current design methods used for the axial bearing resistance, namely API Main Text method and cone penetration test (CPT)-based design methods, such as simplified ICP-05, offshore UWA-05, Fugro-05 and NGI-05 methods. Based on these new model errors, a reliability-based study towards the safety was conducted by performing a Monte-Carlo simulation. In addition, consequences regarding the deterministic pile design in terms of quality factors were evaluated. It is shown that the current global safety factor (GSF) prescribed and the partial safety factors are only valid for the API Main Text and the offshore UWA-05 design methods; whereas for the simplified ICP-05, Fugro-05 and NGI-05 design methods, an increase in the required embedded pile length and thus in the GSF up to 2.69, 2.95 and 3.27, respectively, should be considered to satisfy the desired safety level according to DIN EN 1990 of β = 3.8. Further, quality factors for each design method on the basis of all reliability-based design results were derived. Hence, evaluation of each design method regarding the reliability of the pile capacity prediction is possible.     

In vitro model to assess the adsorption of oral veterinary drugs to mycotoxin binders in a feed- and aflatoxin B1-containing buffered matrix

Mycotoxin binders are feed additives which are mixed in the feed to adsorb mycotoxins and thereby reducing their toxic effects on animals. Interactions with orally administered veterinary medicinal products, such as antimicrobials or coccidiostats, have been reported previously. This paper describes an in vitro model to screen the interaction between mycotoxin binders and veterinary drugs with respect to the non-specific binding of drugs. It is designed as a static setup using a single concentration of drug and binder in a feed-containing or a feed-plus-mycotoxin-containing matrix, buffered at different pH values. The model was applied to two frequently used antimicrobials in veterinary medicine, doxycycline (DOX) and tylosin (TYL), one major mycotoxin, aflatoxin B1 (AFB1), and four mycotoxin binders. Proportions of feed, DOX or TYL, AFB1, and binder are equivalent to the in vivo situation for broiler chickens, while pH and volume of the buffer are representative of the gastrointestinal tract of chickens. A substantial binding of DOX (~ 88%) and TYL (~ 66%) to the feed-matrix was observed. For the mycotoxin binders, similar results were obtained for DOX and TYL; more specifically up to an inclusion rate of 20 g binder/kg feed, no significant binding was demonstrated, determined as the free concentration of DOX and TYL. A single exception was noticed for TYL and one specific bentonite-based mycotoxin binder, for which no significant interaction could be demonstrated up to 10 g binder/kg but there was an effect at 20 g/kg. In all cases, there was no competition between the tested drugs DOX or TYL and the mycotoxin AFB1 for binding to the bentonite-based mycotoxin binder.     

三种回生抗性淀粉对米淀粉的冻融与流变性质的影响

研究了添加锥栗、马铃薯与绿豆回生抗性淀粉(RS3)对米淀粉的冻融稳定性与流变学性质的影响。结果表明:添加锥栗、马铃薯与绿豆RS3都能显著提高米淀粉凝胶的持水率,且冻融超过3次后,其影响的差别越来越显著。随着冻融次数增多,米淀粉凝胶中不易流动水明显降低、自由水显著增加;当冻融次数相同时,添加RS3可使米淀粉凝胶中不易流动水明显增多而自由水显著减少。添加锥栗、马铃薯和绿豆RS3后,米淀粉糊的黏性模量明显增加,而弹性模量的增加更加显著。在相同剪切速率下,添加锥栗、马铃薯和绿豆RS3可以使米淀粉糊的抗剪切强度大大增强。添加相同质量浓度的锥栗、马铃薯和绿豆RS3后,米淀粉糊的稠度系数都大大升高、流体指数和滞后环面积显著减小。     

New approaches to determine the interface height of fire smoke based on a three-layer zone model and its verification in large confined space

Large confined space has high incidence of fires, which seriously threatens the safety of people working there. Understanding the distribution of smoke in such large space is critical to fire development prediction and smoke control. Three improved methods for the stratification interface prediction of fire smoke are developed, including of improved intra-variance, integral ratio and N-percentage methods. In these methods, the interface height is determined by the vertical temperature distribution based on a three-layer smoke zone model, which is an improvement of a two-layer zone model. Thereafter, the three improved methods are applied to several typical fire cases simulated CFD to predict the smoke interface, and their applicability and reliability are verified by comparison of the smoke stratification results with the filed simulation results. Results show that the three improved methods can effectively determine the location of the three-layer zone model's interface, and they have the ability to predict smoke interface for fires with different fire source types and ventilation conditions.     

我国煤矿生产事故统计及安全生产措施

我国煤矿生产事故频发,顶板垮落、瓦斯爆炸、机电事故、突水、矿井火灾、放炮等隐患时刻影响着煤矿安全生产,当前矿井开采以井下开采为主,井下开采存在技术要求高、开采难度大的问题,导致煤矿事故发生数和死亡人数相对其他行业居于首位。因此,为了深入研究煤矿事故发生原因和规律,统计了近10 a我国煤矿事故数据,找出当前矿山开采存在的各种安全问题,针对存在的问题提出解决措施,对预防及应对煤矿安全问题具有重要意义。