制药废水经稳定塘处理用于农灌的可行性探讨

利用以厌氧塘为主体,以预沉池、二级厌氧塘、兼性塘组成的工艺,探讨了制药废水经过稳定塘处理后用于农灌的途径。在停留时间为7—11d时,COD去除率冬季为47％,夏季达到76.6％,夏季厌氧塘削减COD负荷达150g/m~3·d.其出水水质指标基本满足灌溉要求.还对气温、有机负荷、pH等对处理效果的影响进行了探讨。     

粉煤灰钝化污泥对土壤理化性质及玉米重金属累积的影响

通过温室盆栽试验研究施用不同量及不同比例粉煤灰钝化污泥对土壤理化性质、玉米生长和重金属累积的影响。试验结果表明：施用粉煤灰钝化污泥能显著提高酸性土壤的pH值和Ca、Mg、B的含量,降低土壤的电导率和重金属的有效性。施用合适比例和合适量的粉煤灰钝化污泥能明显改善土壤的物理性质,增加土壤的N、P养分,并能显著提高玉米地上部干物重。10％和5％是高施用量和低施用量时合适的粉煤灰加入比例,施用此比例粉煤灰钝化污泥时,玉米的地上部干物重显著高于施用化肥的对照土壤或于之相当,且没有硼和重金属的毒害。     

安全投资决策的可变模糊优选方法

合理进行安全投资,实现企业本质安全,是建立企业安全生产长效机制的有效途径之一,对社会生产的良性发展起着至关重要的作用。在分析了安全投资决策问题和重要性概念的基础上,提出了一种客观确定指标重要性的可变模糊优选方法。该方法首先利用灰色关联分析确定各指标的重要性排列顺序,然后对各指标进行重要性的二元比较以确定权重向量,最后依据指标特征值矩阵,结合指标权重向量,计算各方案在不同模型下的相对优属度向量,进而得到平均相对优属度向量,并以此进行决策。通过实例评价及分析,可变模糊优选方法科学实用,计算过程简单易懂,能够提高决策的可靠性,评价结果清晰展现了企业以往安全投资状况,为今后科学合理地制定安全投资策略指明了方向。     

基于可变模糊优选理论的应急指挥决策

在分析应急指挥决策方案的优选问题基础上,将可变模糊理论引入公共安全领域,提出应急指挥方案优选的可变模糊方法。该方法依据指标特征值矩阵,结合指标权重向量,计算各方案在不同模型下的相对优属度向量,并以此进行决策。其特点是模型可以变化以提高系统决策的可靠性。结合应急救援实例探讨可变模糊优选方法在应急决策中的应用,并与文献中的方法进行比较,表明可变模糊优选理论对于解决优选决策问题可行、有效,有助于指导应急决策实践。     

基于AHP的高处坠落事故脆性分析

高危建筑行业施工作业中高处坠落事故居于“五大伤害”事故之首。以高处坠落事故的发生为研究对象,由层次分析法得出导致事故发生的各因素的相对重要度的排序向量,根据复杂系统的脆性理论,通过脆性激发度的定义,对高处坠落事故进行了脆性分析。结果表明,使用不安全设施、无防护措施、强度不够和处于不安全位置这四种因素是导致高处坠落事故发生的主要脆性源。研究结果为建筑行业事故防控体系的建立提供一种新的途径和思路。     

大连市交通噪声环境质量二级模糊综合评价

采用基于模糊数学的综合二级评判方法评价大连10条城市道路交通环境噪声污染程度。结果表明,受交通噪声冲击影响最大的是西安路大连商业城居民小区路段,影响最小的是如意街大连商业城居民小区路段,与实际调查结果基本一致,体现了该评价方法的合理性和科学性。     

压实度和含水率对铁尾矿抗剪强度影响的试验分析

以阜新同乃铁矿排放的铁尾矿为研究对象,经试验得出其级配不良,属于含砂低液限粉土.通过室内试验分析了不同含水率和压实度条件下铁尾矿的抗剪强度.结果表明,铁尾矿的抗剪强度与其含水率和压实度之间有很大的相关性.相同压实度条件下,黏聚力随含水率升高呈先增大后减小的规律,存在特征含水率,在特征含水率条件下黏聚力达到最大值.黏聚力与含水率可近似拟合为二次函数.土颗粒间的水膜联结和胶结作用对黏聚力的产生具有重要作用,黏聚力因含水率的不同而变化较大.试验得出含水率变化对铁尾矿内摩擦角的影响较小,这是因为砂土的内摩擦角与砂土的颗粒结构、大小及密实程度密切相关,而铁尾矿中的粗粒含量较高,含水率变化不会引起其颗粒结构、大小及密实程度的显著变化.在相同含水率条件下,铁尾矿的黏聚力和内摩擦角均随压实度增大而呈近似线性增大.不同含水率和压实度条件下,铁尾矿的黏聚力均不大,铁尾矿的抗剪强度主要依靠内摩擦角的贡献.考虑铁尾矿材料的抗剪强度因压实度和含水率不同而变化,可使尾矿库稳定性分析结果更符合实际情况.     

Foaming agent self-suction properties of a jet-type foam preparation device used in mine dust suppression

In this study, we introduce a jet-type foam preparation device for use in mine dust control, which can enhance the reliability and applicability of the foam production process compared with conventional foam generators. In order to elucidate the foaming agent self-suction properties of this novel foam generator, we used a self-built experimental setup to investigate the effects of the working pressure and outlet pressure on negative pressure (vacuum degree) during foaming agent suction, as well as the functional relationship between negative pressure and the foaming agent by adding parameters. We also studied the effects of the valve opening degree on the foaming agent flow rate and addition ratio. The results showed that the working pressure and outlet pressure affected the formation of negative pressure in a positive linear manner and a negative linear manner, respectively. Thus, the negative pressure increased linearly as the working pressure increased, whereas it decreased in a linear manner as the outlet pressure increased. There was also a quadratic relationship between the vacuum degree and foaming agent quantity with the piecewise characteristics of the growth process, where they increased slowly with a lower vacuum degree but increased rapidly with a higher vacuum degree. After creating a moderate negative pressure with the water jet, the foaming agent could be added automatically at a low flow rate with a low ratio via the regulating valve on the liquid suction hose. This study provides basic information that should facilitate the application of this novel foam preparation technique.     

Performance of sequential anaerobic/aerobic digestion applied to municipal sewage sludge

A promising alternative to conventional single phase processing, the use of sequential anaerobic-aerobic digestion, was extensively investigated on municipal sewage sludge from a full scale wastewater treatment plant. The objective of the work was to evaluate sequential digestion performance by testing the characteristics of the digested sludge in terms of volatile solids (VS), Chemical Oxygen Demand (COD) and nitrogen reduction, biogas production, dewaterability and the content of proteins and polysaccharides. VS removal efficiencies of 32% in the anaerobic phase and 17% in the aerobic one were obtained, and similar COD removal efficiencies (29% anaerobic and 21% aerobic) were also observed. The aerobic stage was also efficient in nitrogen removal providing a decrease of the nitrogen content in the supernatant attributable to nitrification and simultaneous denitrification. Moreover, in the aerobic phase an additional marked removal of proteins and polysaccharides produced in the anaerobic phase was achieved. The sludge dewaterability was evaluated by determining the Optimal Polymer Dose (OPD) and the Capillary Suction Time (CST) and a significant positive effect due to the aerobic stage was observed. Biogas production was close to the upper limit of the range of values reported in the literature in spite of the low anaerobic sludge retention time of 15 days. From a preliminary analysis it was found that the energy demand of the aerobic phase was significantly lower than the recovered energy in the anaerobic phase and the associated additional cost was negligible in comparison to the saving derived from the reduced amount of sludge to be disposed.     

上市航空公司盈利能力综合评价

自2008年以来,我国航空业一直处于发展低谷,评价航空公司的盈利能力及分析提高盈利能力的对策是一关键问题.许多学者习惯于应用单一的评价方法对航空上市企业进行评价,然而在对同一批航空上市企业进行评价时,不同的方法得出了不同的评价结果.基于此状况,提出一种系统的综合评价方法,并对全国12家典型航空上市企业进行综合评价,克服了以往应用单一方法在评价中的片面性,使评价结果更加全面客观.