Effects of biochars on the bioaccessibility of phenanthrene/pyrene/zinc/lead and microbial community structure in a soil under aerobic and anaerobic conditions

The immobilization of co-contaminants of organic and inorganic pollutants by biochar is an efficient remediation strategy. However, the effect of biochar amendments on the bioaccessibility of the co-contaminants in dry versus flooded soils has rarely been compared. In batch experiments, bamboo-derived biochar(BB) had a higher sorption capacity for phenanthrene(Phe)/pyrene(Pyr)/zinc(Zn) than corn straw-derived biochar(CB), while CB had a higher sorption capacity for lead(Pb) than BB. After 150 days of incubation, the amendments of 2% CB, 0.5% BB and 2% BB effectively suppressed the dissipation and reduced the bioaccessibility of Phe/Pyr by 15.65%/18.02%, 17.07%/18.31%and 25.43%/27.11%, respectively, in the aerobic soils. This effectiveness was more significant than that in the anaerobic soils. The accessible Zn/Pb concentrations were also significantly lower in the aerobic soils than in the anaerobic soils, regardless of treatments.The Gram-negative bacterial biomass and the Shannon–Weaver index in the aerobic soil amended with 2% CB were the highest. The soil microbial community structure was jointly affected by changes in the bioaccessibility of the co-contaminants and the soil physiochemical properties caused by biochar amendments under the two conditions. Therefore, dry land farming may be more reliable than paddy soil cultivation at reducing the bioaccessibility of Phe/Pyr/Zn/Pb and enhancing the soil microbial diversity in the short term.     

基于API极限工况下修井机井架强度计算研究

为研究井架在复杂工况下的强度与安全问题,以现场使用的350型修井机井架为研究对象,采用数值模拟对井架进行参数化建模;按照极限作业工况下24种组合载荷对井架进行强度分析,得出操作工况、非预期工况和可预期工况下井架的最大变形和应力云图;提取计算井架构件UC值的相关数据,对井架进行强度、刚度和整体安全性校核。结果表明:井架在常规风力作用下,最大钩载作业工况为其主要受力工况,此时井架最大等效应力小于许用应力,可满足安全需求;在相关工况中,井架的最大等效应力集中出现在上下体连接处、二层台和底部大腿处,计算井架构件各工况下的UC值均小于许用最大UC值,表明井架结构综合强度足够,满足API标准使用要求。     

石油企业安全目标管理运行模式研究

为了提高石油企业安全管理水平,确保石油企业的安全生产。通过分析石油企业安全生产与管理的重要性,提出适合石油企业安全目标管理运行模式的内涵及不足,同时,结合企业的实际情况建议从以下3方面:建立安全目标管理战略、加强安全目标管理的实施与监督、加强沟通与考核机制的建立来完善安全目标管理运行模式,才能更好地实现石油企业安全管理的目标,实现持久、健康的发展。     

冶金生产企业风险分级研究

冶金行业存在诸多风险,对其进行风险分级研究可以更好地做好预防工作。首先对冶金企业的危险有害因素进行了辨识;其次,建立冶金企业风险指标体系;最后,运用MATLAB与灰色变权聚类分析法计算风险等级。结果表明,违反操作规程的风险等级最高,是影响冶金企业生产风险级别的最高指标,遵守操作规程是企业安全工作的管理重点。     

不同煤质煤尘层最低着火温度特性及其影响因素研究

为研究不同煤质的煤尘层最低着火温度特性及其影响因素,选取褐煤、长焰煤、不粘煤、气煤、焦煤、瘦煤、贫煤和无烟煤8种不同变质程度的煤尘样品,测试分析8种煤尘层的最低着火温度及最低着火温度工况下煤尘层着火类型、着火时间,并研究了粒径和煤尘层厚度对煤尘层最低着火温度的影响。结果表明,随变质程度由褐煤逐渐增大,最低着火温度T_L由290℃不断增大。褐煤、长焰煤、不粘煤和气煤为a类着火,其着火时间较为接近,均值为19. 5 min,而焦煤、瘦煤和贫煤为c类着火,着火时间均值为11 min,表明随变质程度增大,虽然TL增大,但着火时间明显缩短。通过分析最低着火温度工况下不同煤质的温度T-时间t变化情况,认为褐煤、长焰煤、不粘煤和气煤煤尘层温度曲线中出现明显上下波动现象,是因为煤尘层厚度有限,无法长时间积聚能量。通过构建TL与粒径r、煤尘层厚度d的三维空间拟合模型,发现粒径小、厚度大的煤尘层具有更大的着火敏感性和爆炸潜伏性,更应加强防范。     

Value congruence,control, sense of community and demands as determinants of burnout syndrome among hospitality workers

Employees working in the hospitality industry are constantly exposed to occupational stressors that may lead employees into experiencing burnout syndrome. Research addressing the interactive effects of control, community and value congruence to alleviate the impact of workplace demands on experiencing burnout is relatively limited. The present study examined relationships among control, community and value congruence, workplace demands and the three components of burnout. A sample of 418 employees working in a variety of hospitality associations including restaurants and hotels in Spain were recruited. Moderation analyses and linear regressions analyzed the predictive power of control, community and value congruence as moderating variables. Results indicate that control, community and value congruence were successful buffers in the relationships between workplace demands and the burnout dimensions. The present findings offer suggestions for future research on potential moderating variables, as well as implications for reducing burnout among hospitality employees.     

Ca and OH release of ceramsites containing anorthite and gehlenite prepared from waste lime mud

Lime mud is a kind of solid waste in the papermaking industry, which has been a source of serious environmental pollution. Ceramsites containing anorthite and gehlenite were prepared from lime mud and fly ash through the solid state reaction method at 1050°C. The objective of this study was to explore the efficiency of Ca^2 + and OH⁻ release and assess the phosphorus and copper ion removal performance of the ceramsites via batch experiments, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that Ca^2 + and OH⁻ were released from the ceramsites due to the dissolution of anorthite, gehlenite and available lime. It is also concluded that gehlenite had stronger capacity for Ca^2 + and OH⁻ release compared with anorthite. The Ca^2 + release could be fit well by the Avrami kinetic model. Increases of porosity, dosage and temperature were associated with increases in the concentrations of Ca^2 + and OH⁻ released. Under different conditions, the ceramsites could maintain aqueous solutions in alkaline conditions (pH = 9.3–10.9) and the release of Ca^2 + was not affected. The removal rates of phosphorus and copper ions were as high as 96.88% and 96.81%, respectively. The final pH values of both phosphorus and copper ions solutions changed slightly. The reuse of lime mud in the form of ceramsites is an effective strategy.     

澧水流域生态系统服务价值与生态补偿策略

为了协调区域经济发展与生态保护的关系,以澧水流域为研究对象,采用修正的生态系统服务价值系数分析了2001—2013年该区域生态系统服务价值(ESV)的变化情况,并构建灰色模型对2016—2025年生态系统服务价值进行预测,同时综合考虑研究区域经济发展水平,引入生态补偿优先级(ECPS)对不同区域生态补偿的迫切程度进行了量化. 结果表明:①2001—2013年,澧水流域生态系统服务价值从2001年的313.70×108元降至2013年的313.32×108元;GM(1,1)模型预测结果显示,2025年澧水流域生态系统服务价值将降至311.22×108元. ②澧水流域8个县(市/区)的生态系统服务价值和生态补偿优先级存在较大差异,澧水上游(桑植县)和中游(永定区、武陵源区、慈利县、石门县)为整个澧水流域提供了良好的生态服务,属于“生态输出”地区,应该优先得到生态补偿;而下游(澧县、临澧县、津市市)的生态优先级较小,属于“生态消费”地区,应当率先进行生态支付. 研究结果有利于制订合理的生态补偿价格,调节生态保护利益相关者之间的利益关系,有助于当地政府研究制订比较完整的生态补偿政策决策.      

数值模拟在群桩基础评判标准确定中的应用

群桩基础安全稳定性评判决策中各因子评判标准边界的确定是保证其模型正确构建的关键环节。由于安全监测系统无法测得这种警戒值,因此,本文采用基于ABAQUS软件的数值模拟方法,依据上部结构受力特点及使用要求来确定群桩基础安全稳定性判别决策因子的警戒值。仿真结果显示:该方法能可靠获取超大型深水群桩基础成桥后的基桩轴力不均匀性和差异沉降的最佳警戒值。     

安全管理在企业发展不同时期的重要性分析

本文从安全管理的现状分析了安全管理的必要性,用层次分析法分析了企业发展不同时期影响因素的权重,定量地分析了安全管理的重要性。