矿井瓦斯控爆技术及材料研究进展

瓦斯爆炸灾害防治一直是我国煤矿安全研究的热点、难点。通过对国内外相关文献总结分析,从瓦斯抑爆装置、抑爆介质及抑爆机理3个方面综述了目前国内外矿井瓦斯抑爆技术及抑爆材料的研究现状,提出了未来的发展方向。研究结果表明:瓦斯抑爆技术的有效性和可靠性主要取决于抑爆介质的物理化学性质、控爆空间几何参数、爆炸特性参数和抑爆系统中爆炸探测方式等因素;结合瓦斯爆炸链式反应理论和探测技术的发展,研究应更多地关注抑爆过程的微观特性,揭示其详细的抑爆作用机理,为探寻新型高效、绿色抑爆材料提供更有力的理论支持。     

开敞空间可燃气云爆炸冲击波超压及灾害动力响应研究评述

为了进一步梳理和分析开敞空间可燃云爆炸冲击波超压传播规律及灾害动力响应方面的各项研究成果,推进可燃气体爆炸安全防控,减少人员伤亡和经济损失。在分析现有研究的基础上,总结开敞空间可燃气云爆炸冲击波超压传播规律及灾害动力响应研究等方面存在的不足,提出开敞空间多元混合气体爆炸冲击波超压传播规律研究、多影响参数下可燃气云爆炸冲击波超压传播规律定量分析、基于可燃气云爆炸冲击波超压作用下的承载体动力响应等未来研究的关键技术问题。     

几种裸子植物胚乳愈伤组织的诱导

取裸子植物未成熟胚乳作为外植体，在改良MS、添加不同种类激素和不同浓度配比的培养基上．分别予以热激、光培养、暗培养和刻伤胚乳等多种处理进行培养．结果表明：刻伤胚乳和适时暗培养有利于愈伤组织发生；经过25～30d的培养，在ρ（NAA）＝0．5～0．75mg／L、ρ（2，4－D）＝0．2～0．5mg／L、蔗糖浓度5％的培养基上，油松、白皮松、青、华北落叶松以附加ρ（KT）1．0～2．0mg／L以及白、侧柏在BA与KT配合使用的培养基上，热激后暗培养，愈伤组织诱导频率可达86．4％．     

Plasma levels of androgens and gonadal development of breeders and helpers in the bell miner (Manorina melanophrys)

Plasma concentration of androgens and gonad development were studied in wild cooperatively breeding bell miners (Manorina melanophrys) of different age, sex and social status. Plasma levels of androgens increased with age of birds. For sexually mature (SM) bell miners, androgen levels were higher in breeders than in nonbreeding (NB) helpers (P < 0.005), and they were marginally higher in females than in males (P < 0.10). Thus female breeders showed the highest plasma levels of androgens. This pattern may be explained by an asymmetry between the sexes in the levels of competition needed to reach and defend breeding status; the degree of intra-sexual competition seems to be higher among female bell miners than among males. In general, male breeders had larger gonads than male SMNB helpers; male breeder gonads produced spermatozoa whereas most helpers' gonads did not. However, old (i.e. 34 months) SMNB male helpers had large gonads producing spermatozoa in spite of having low plasma levels of androgens. We suggest that young male bell miners may be under a voluntary mechanism of reproductive suppression perhaps favoured by inbreeding avoidance; although some aggressive interactions observed between very young helpers (about 2 months) and adult members of the breeding unit suggests that a certain degree of imposition also occurs at young ages. Older male helpers may avoid aggression with the male breeder and imposed reproductive suppression, hence the low circulating levels of androgens, but they have the potential to sneak extra-pair copulations. Gonad size decreased during the non-breeding season in both sexes.     

基于数据驱动的石化装置静态报警抑制策略研究

由生产状态变化引起的误报警频发,为解决现有针对基于状态报警的抑制方法缺乏完整性与定量分析的问题,提出了新的报警抑制策略。通过分析报警记录等数据库,对引起报警的生产条件进行结构化整定并量化,利用分类筛选与数据过滤找出基于状态的报警,再结合关联性分析和概率判断,建立了基于数据驱动的静态报警抑制策略。使用现场数据的试验证明了该方法的有效性。     

One-step estimation method and nomogram to predict safety distances of pressurized gas pipelines from blast sources

Pressurized gas pipelines may be endangered by accidental or intentional activities causing excess ground vibrations leading to failure. Thus, many papers have been published on this issue, yet most of these efforts suffer from complexity and inability to ascertain that all engaged factors are taken into account. These factors are attributed, namely, to explosion source, explosion-ground interaction, energy transfer through the ground, ground-pipeline interaction, and response of the pipeline. The deterministic method developed previously by the author has derived useful prediction mathematical formulas that can be used to calculate, either the stand-off distance of purposefully used explosives, or the maximum quantity of explosives to be used at a given distance, or the equivalent stress of a pipeline induced by an explosive charge at a given standoff distance. The method can also be applied to accidental blast events in factories or other activities. Yet, the complex formulas developed are hard to be used in the field and a simpler approach is needed to facilitate and accelerate in-field estimations. Thus, a nomogram was prepared to make the safety estimations easy and fast and taking into account all engaged critical factors starting from the explosion source through the integrity of the structure.     

Coupling effects of the explosion shock wave and heat radiation on the dynamic response of a fixed-roof tank

The occurrence of leakage in large tank farms or oil deposits can lead to fire or explosion accidents. Coupling effects of fire and explosion loadings can cause considerably more damage to adjacent tanks or buildings than either loading individually does. In this study, the combined loadings of the explosion shock wave and heat radiation from a pool fire on a neighboring empty fixed-roof tank were numerically investigated. The effects of the explosion shock wave intensity and relative height of the explosion center [the ratio of the height of the explosion center to the height of the tank (h_r)] were analyzed. The results indicate that tanks damaged by explosion shock waves have decreased fire resistance and critical buckling temperature. Moreover, the thermal buckling deformation of the predamaged tank largely depends on the explosion shock wave. With an increase in the explosion shock wave intensity or a decrease in h_r, the explosion shock wave has greater influence on the fire resistance of the tank, and the critical buckling temperature decreases. This paper can provide an understanding of the dynamics of a tank under explosion shock wave loading, and of the critical failure criterion and failure modes of a target tank under the coupled loading of the explosion shock wave and an adjacent pool fire.     

Experimental study on the inhibition of methane/air explosion by modified attapulgite powder

In order to explore the influence of attapulgite powder on the methane explosion, a small-size semi-closed visual explosion experiment platform was built, and experiments were carried out. The effect of spraying powder on the whole process of methane explosion was studied when methane concentration was 7%, 8%, 9.5%, 11% and 12%, respectively. When the methane concentration was 11%, the maximum explosion overpressure dropped by modified spraying attapulgite powder was as high as 33.26%, and at the same time, the reduction rate of flame propagation velocity reached the maximum value of 36.65%. Furthermore, when the methane concentration was 9.5%, the experimental results when the powder spraying amount of modified attapulgite was 120 mg, 160 mg, 200 mg, 240 mg and 280 mg showed that when the powder spraying was 240 mg, the maximum explosive overpressure decreased by 33.14%, and the reduction rate of the peak flame propagation velocity reached the maximum value of 33.73%. Through the video images recorded by the high-speed camera, the flame structure, shape, color, etc. Were analyzed. The characterization analysis illustrated that the modified attapulgite powder has a small particle size, relatively large porosity and specific surface area. Also, it has a high weight loss rate. Combined with the results of characterization analysis, the explosion suppression mechanism of modified attapulgite powder was discussed. It was found that the modified attapulgite powder could effectively absorb the active free radicals generated in the explosion, and the modified new chemical components have a better thermal decomposition and endothermic effect and a better suppression of methane explosions.     

Removal of ofloxacin antibiotic using heterogeneous Fenton process over modified alginate beads

The aim of this work is to study the heterogeneous oxidative degradation of ofloxacin antibiotic using a composite material prepared from sodium alginate and cyclohexane dinitrilo tetraacetic acid(CDTA). The characterization tests indicated the successful incorporation of metal chelator and iron. It was also demonstrated that the synthesized beads are mesoporous. The influence of several experimental parameters(i.e.: H2O2 dose,working temperature, beads loading and initial drug concentration) on the process performances was evaluated. The reaction temperature significantly affects the drug conversion efficiency. It was also observed that the synthesized material was efficient toward the target antibiotic degradation in the presence of small quantities of hydrogen peroxide. Under optimum conditions(0.05 g of granules, initial drug concentration = 10 mg/L,25 μL of 10 mmol/L H2O2), conducted in a batch reaction, 94% degradation of ofloxacin was reached. The results also indicate that the composite material showed a reasonable stability;a relatively low decrease of activity after four successive runs(only 9%) and a negligible iron leaching(0.8%) have been observed. The synthesized composite material offered interesting advantages in terms of simplicity, good stability, ease of recovery from the liquid medium after use and its efficiency in the presence of low quantities of oxidant. It constitutes a good candidate in the water treatment area.