Experimental study on the suppression of gas explosion using the gas–solid suppressant of CO2/ABC powder

Gas explosion is the leading accident in underground coal mining in China. Using the self-improved 20 L spherical experimental system, the impacts of 8% CO₂, ABC powder at various concentrations and mixture of them on the suppression of mine gas explosion were investigated. The results indicate that cooperative synergism exists between ABC powder and CO₂. Their combination has a better effect than each of the two components acting alone, especially for the gas of larger concentration. When 0.25 g/L ABC powder was mixed with 8% CO₂, the explosion limits were reduced by about 55%, the time to reach the peak explosion pressure was prolonged 3.56 times on average. Meanwhile, the maximum explosion pressure declined on an average of 59.4% and the maximum explosion overpressure rising rate decreased on an average of 91.1%. A combination of 0.20 g/L ABC powder and 8% CO₂ completely suppressed 11% gas explosion. The explosion suppression mechanism of CO₂ and ABC powder were probed theoretically. CO₂ plays a key part in the whole explosion processes, and it can effectively suppress the forward reaction between gas and oxygen. While it is during the middle-later period of explosion processes that ABC powder plays a critical role. The particles decomposed from heated ABC powder such as nitrogen and phosphor will react with free radicals rapidly. Besides, atoms as N, P are capable of participating in chain reaction and reacting with active groups, significantly suppressing the gas explosion.     

铝粉超细化对KClO3/Al/S配方药剂特性的影响

为研究铝粉超细化后对烟火药剂性能的影响,将普通铝粉和纳米铝粉分别与氯酸钾、硫黄粉按照零氧平衡的同一配比(17%Al+63%KClO3+20%S)配制成烟火药剂,分别用0#样品和1#样品表示。用ARC、WL-1型落锤仪和MGY-1型摆式摩擦感度仪等试验装置从热安全性、撞击感度和摩擦感度等方面进行对比试验。结果表明,与含普通铝粉的0#样品相比,含纳米铝粉的1#烟火药剂热分解的初始反应温度明显降低(118.67℃<123.3℃),反应到达最大温升速率所需的时间明显延长(4.94min>0.13 min),反应所能达到的最高压力明显降低(2.77 MPa/g<3.14 MPa/g),反应动力学因子明显降低(361.85 kJ/mol<409.41 kJ/mol),撞击感度明显下降(12%<100%)。这说明铝粉粒径对药剂的性能有一定的影响。纳米铝粉的加入在加速烟火药剂反应进程的同时,可有效降低其反应的激烈程度、压力危险性和撞击危险性,即铝粉超细化后可以有效改善烟火药剂的性能,提高其安全性。     

焙烧条件对废干电池中汞的释放影响研究

在小型管式炉中进行废干电池的焙烧实验,分析了焙烧温度、时间及其交互作用对汞释放的影响.结果表明,焙烧时间对汞释放影响最大,温度也有显著影响,它们对汞释放有交互作用且作用显著,废干电池焙烧过程中汞在低温下更易释放.在温度650 ℃,焙烧时间120 min情况下,汞释放率达99%以上.焙烧前后干粉的X衍射分析结果表明,焙烧后电池中含有的晶态物增加,结构更复杂.     

粉料无尘装车技术的应用及发展

传统除尘器卸灰、输灰系统存在工艺繁杂、能耗大、输送速度慢、设备故障率高、系统难以维护及二次扬尘等问题,采用新型粉料无尘装车技术可有效简化工艺,提高生产速度和系统运行、维护可靠性,很大程度上减少能耗并彻底根除二次扬尘。     

14C-Ethion residues in soybean seeds: metabolic pathway,effect of processing,bioavailability, toxicity and protective action of artichoke leaf powder towards rats

The metabolic fate of ethion labeled with ¹⁴C-at the ethyl ester groups in soybean seeds following topical application to leaves was studied. Chromatographic analysis of soybean oil revealed the presence of the parent compound together with four metabolites which were identified as ethion monooxon, ethion dioxon, O-ethyl phosphorothioate and O,O-diethyl phosphorothioate. The effect of processing on ethion residues in soybean oil was investigated. The refined oil contained small amounts of the ¹⁴C-residues originally present (37.5%). Upon feeding rats with the cake containing ethion bound residues, a substantial amount of ¹⁴C-residues was eliminated in the urine (73%), and about 6% excreted with the feces. About 5% of the radioactive residues were distributed among various organs. Mature male Wistar rats were fed on soybean seeds containing ethion residues (1.93 ppm), and on artichoke leaves powder (1% W/W) for four weeks. At the end of the experimental period, the ethion-treated group had a significantly higher alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) activity, urea, creatinine, total cholesterol (TC), triglycerides (TG), and very low density lipoprotein (VLDL) levels. The ethion-treated rats also had a lower total serum protein and albumin levels, as well as acetyl cholinesterase (AChE), catalase (CAT), and glutathione-S-transferase (GST) activity as compared with controls. Moreover, concomitant treatment with artichoke leaf powder improved, at least partially, all the biochemical parameters that were altered by ethion.     

Geometry of Zn(II) complexes with dissolved organic matter: X-ray studies at variable pH

The structure of Zn(II) complexes with dissolved organic matter (DOM) is an important consideration in developing molecular-level models of Zn(II) speciation, but recent reports favoring the tetrahedral geometry differ from earlier findings that geometry was largely octahedral. In general, the presence of thiolate ligands favors the tetrahedral geometry, while O and N ligands favor the octahedral geometry. This work presents extended X-ray absorption fine structure (EXAFS) and X-ray absorption near-edge structure (XANES) spectroscopic results, indicating an octahedral geometry over the pH range of 5–9 for a freshwater DOM isolate. Changes in XANES derivatives as a function of pH can be explained in terms of ligand protonation and/or changing ligand groups. Tetrahedral Zn(II)–DOM geometry may be restricted to binding environments containing thiol groups.     

The uptake and translocation of selected elements by cole (Brassica) grown using oasis soils in pot experiments

Pot experiments were conducted on cole (Brassica) grown in soils jointly treated with traces of two heavy metals cadmium (Cd) and zinc (Zn). As the concentration of heavy metals in the soil increased, the uptake of these metals by the plants rose. However, the ratio of heavy metal concentration in soil to uptake by plants increased at a slower rate. Bioavailability of heavy metals considered between the roots and soil using non-linear regressions was shown to be statistically significant. Similarly, the bioavailability of these two heavy metals between leaves and roots using a linear regression was also statistically significant. The bioconcentration factors (BCFs) for Cd and Zn were 0.282 and 4.289, respectively. Significant variation of BCF with the heavy metal bioavailability in soil was noted from non-linear models. The transfer factors (TFs) were 4.49 for Cd and 1.39 for Zn. The Zn concentration in leaves under all treatments did not exceed threshold set standards, but Cd levels exceeded these standards when the concentration of Cd in the soil was more than 1.92 mg kg^?1 dry weight (dw). Data indicate that cole (Brassica) is not a suitable crop for oasis soils because of plant contamination with heavy metals, especially Cd.     

Zn2+及Fe3+对嗜淀粉乳杆菌开放式发酵产乳酸的影响

研究了在餐厨垃圾中接种嗜淀粉乳杆菌进行开放式乳酸发酵(即发酵原料不灭菌)的可行性,探讨了添加Fe3+、Zn2+的发酵体系中相关酶活与代谢产物的关系.结果表明,开放式发酵体系的乳酸产量高于非开放式发酵体系.加Fe3+体系的乳酸脱氢酶活性较高,导致乳酸产量增加(最高达29.5g/L),比未添加微量元素的对照体系增加了24.2%;而加Zn2+体系的乙醇脱氢酶(ADH)活性较高,导致副产物乙醇产量的增加,从而使乳酸产量低于对照体系;添加不同微量元素时嗜淀粉乳杆菌对底物中淀粉的利用率由高到低的顺序为:加Fe3+体系(65.7%) > 对照体系 (38.5%)>Zn2+体系(28.1%).此外,在嗜淀粉乳酸菌的发酵体系中,蔗糖和麦芽糖比乳糖容易降解成葡萄糖,果糖,最终被乳酸菌利用.     

锌对汞胁迫下小麦幼苗生理特性的影响

通过沙基培养方法研究不同浓度锌(Zn)对汞(Hg)胁迫下小麦幼苗叶绿素相对含量(SPAD)、丙二醛(MDA)与脯氨酸的积累及抗氧化酶活性等的影响.结果表明:单独Hg(10 mg L-1)胁迫下,小麦幼苗叶绿素含量降低,超氧化物歧化酶(SOD)与过氧化氢酶(CAT)活性受到抑制,MDA与脯氨酸含量升高.加入10 mg L-1Zn后,叶绿素含量比Hg单独胁迫升高了5.6%,MDA含量降低了32.4%,表明该浓度Zn在一定程度上缓解了Hg对小麦幼苗的毒害;Zn浓度高于10 mg L-1的处理中,叶绿素含量逐渐降低,MDA则呈升高趋势,表明随Zn浓度升高,Zn对Hg毒害的缓解作用逐渐降低.低浓度Zn(10~20 mg L-1)提高了Hg胁迫下小麦幼苗SOD与CAT活性,其活性随Zn浓度升高逐渐增加,20mg L-1Zn处理下,两种酶活性比Hg单独胁迫分别升高了103.3%与71.0%,高浓度Zn(50~100 mg L-1)处理下,两种酶活性则呈下降趋势,表明Zn对Hg胁迫下两种酶活性的促进作用逐渐减弱.在试验设置的Zn浓度范围内,脯氨酸含量均低于Hg单独胁迫,并且低于对照,说明外加Zn抑制了脯氨酸的生成.综上所述,10~20 mg L-1的Zn可以在一定程度上缓解10 mg L-1Hg对小麦幼苗造成的毒害.     

纳米Zn/Al-水滑石对Hela细胞的氧化应激效应

为初步探讨纳米Zn/Al-水滑石对Hela细胞的氧化应激效应,采用不同浓度的纳米Zn/Al-水滑石悬液(0、50、100、200、400、800μg·mL-1)对Hela细胞进行染毒,12h后检测Hela细胞中超氧化物歧化酶(SOD)活性和谷胱甘肽(GSH)含量.结果表明,随着纳米Zn/Al-水滑石染毒浓度的升高,Hela细胞SOD活性逐渐降低,较低浓度组(≤100μg·mL-1)与对照组无显著性差异(p>0.05),较高浓度组(≥200μg·mL-1)与对照组存在显著性差异(p<0.01);随着纳米Zn/Al-水滑石染毒浓度的升高,Hela细胞GSH含量也逐渐降低,较低浓度组(≤50μg·mL-1)与对照组无显著性差异(p>0.05),较高浓度组(≥100μg·mL-1)与对照组存在显著性差异(p<0.05或p<0.01);在实验浓度下,Hela细胞SOD活性和GSH含量与纳米Zn/Al-水滑石染毒浓度呈明显的剂量-效应关系.以上结果提示,较高浓度的纳米Zn/Al-水滑石对Hela细胞可产生一定的氧化应激效应,较低浓度的纳米Zn/Al-水滑石则具有一定的生物相容性.