河滩包气带中残油静态释放模型研究

通过释放试验,模拟了包气带中残残油在河流中刷及积水浸泡条件下残油和释放过程,讨论了温度对释放的影响,建立释放模型,并得到释放速率常数。结果表明残油释放由初始快速和随后的慢速两个过程组成。     

MSWNet: A visual deep machine learning method adopting transfer learning based upon ResNet 50 for municipal solid waste sorting

● MSWNet was proposed to classify municipal solid waste. ● Transfer learning could promote the performance of MSWNet. ● Cyclical learning rate was adopted to quickly tune hyperparameters. An intelligent and efficient methodology is needed owning to the continuous increase of global municipal solid waste (MSW). This is because the common methods of manual and semi-mechanical screenings not only consume large amount of manpower and material resources but also accelerate virus community transmission. As the categories of MSW are diverse considering their compositions, chemical reactions, and processing procedures, etc., resulting in low efficiencies in MSW sorting using the traditional methods. Deep machine learning can help MSW sorting becoming into a smarter and more efficient mode. This study for the first time applied MSWNet in MSW sorting, a ResNet-50 with transfer learning. The method of cyclical learning rate was taken to avoid blind finding, and tests were repeated until accidentally encountering a good value. Measures of visualization were also considered to make the MSWNet model more transparent and accountable. Results showed transfer learning enhanced the efficiency of training time (from 741 s to 598.5 s), and improved the accuracy of recognition performance (from 88.50% to 93.50%); MSWNet showed a better performance in MSW classsification in terms of sensitivity (93.50%), precision (93.40%), F1-score (93.40%), accuracy (93.50%) and AUC (92.00%). The findings of this study can be taken as a reference for building the model MSW classification by deep learning, quantifying a suitable learning rate, and changing the data from high dimensions to two dimensions.     

基于SVR的含缺陷管道剩余强度研究

针对采用标准预测含缺陷管道剩余强度误差较大这一问题,在Matlab中建立基于SVR的含缺陷管道剩余强度预测模型,并基于60组含缺陷管道爆破试验数据进行训练测试,以验证模型的实际性能.结果表明:SVR模型预测测试集结果的最小相对误差为0.55％,最大相对误差为10.35％,平均相对误差为2.63％,预测结果的R2高达0....     

Dissimilatory reduction of FeIII (EDTA) with microorganisms in the system of nitric oxide removal from the flue gas by metal chelate absorption

In the system of nitric oxide removal from the flue gas by metal chelate absorption, it is an obstacle that ferrous absorbents are easily oxidized by oxygen in the flue gas to ferric counterparts, which are not capable of binding NO. By adding iron metal or electrochemical method, Fe^Ⅲ (EDTA) can be reduced to Fe^Ⅱ(EDTA).However, there are various drawbacks associated with these techniques. The dissimilatory reduction of Fe^Ⅲ(EDTA) with microorganisms in the system of nitric oxide removal by metal chelate absorption was investigated. Ammonium salt instead of nitrate was used as the nitrogen source, as nitrates inhibited the reduction of Fe^Ⅲ due to the competition between the two electron acceptors. Supplemental glucose and lactate stimulated the formation of Fe^Ⅱ more than ethanol as the carbon sources. The microorganisms cultured at 50~C were not very sensitive to the other experimental temperature, the reduction percentage of Fe^Ⅲ varied little with the temperature range of 30-50℃.Concentrated Na2 CO3 solution was added to adjust the solution pH to an optimal pH range of 6-7. The overall results revealed that the dissimilatory ferric reducing microorganisms present in the mix-culture are probably neutrophilic, moderately thermophiUc Fe^Ⅲ reducers.     

消防射水与自然冷却下玻璃纤维对灾后混凝土性能影响

本文对火灾后消防射水对玻璃纤维改性混凝土(GF-1)剩余抗压强度的影响进行了研究。分析了GF-1在不同温度、不同冷却方式条件下抗压强度的变化规律,并利用ORIGIN7.5软件拟合了高温作用后GF-1剩余抗压强度与温度之间的关系。研究得出:在两种冷却条件下,二种配比的HPC在高温后剩余抗压强度均呈持续降低,消防射水冷却条件下HPC的剩余抗压强度降低速率大;加热到900℃时,消防射水冷却条件下HPC的剩余抗压强度最低;消防射水对高温作用后GF-1的剩余强度影响很大,射水冷却后GF-1剩余强度明显低于自然冷却的剩余强度;且随着破坏温度升高,经消防射水冷却的GF-1剩余抗压强度呈衰减状态,;GF-1在射水冷却下强度变化没有NC-1快速,与自然冷却条件下的强度变化相比,也呈现出不同的衰减规律;并建立了自然冷却条件下及消防射水冷却条件下GF-1剩余强度与火场温度之间的多阶多项式拟合式。     

地铁地基液化变形的影响因素研究

研究了一些对地铁隧道抗震稳定有较大影响的因素。例如,地铁隧道的整体平均容重和地铁隧道的埋深,尽管它们对地基的孔隙水压力发展影响不大,但却对地铁隧道的震后残余变形影响相当显著。还有,砂性土中粘性土的含量多少对砂性土的动力行为有直接而显著的影响。最后,从能量的角度分析了输入不同地震波的地铁地基土层动力反应的差异。     

不同外源条件下稀土在小麦植株中的残留

采集了全国14个稀土施用区3种不同施用条件（土施、喷施、拌种）下的成熟小麦样品及未施用稀土对照样品，利用等离子体质谱法（ICP－MS）测定了小麦植株的根、茎、叶及籽粒中14种稀土元素的含量。分别探讨了不同外源下小麦植株各部位稀土元素的含量及分布特征，并与有关文献中的报道进行了对比。研究结果表明，土施和拌种的小麦各部位没有发现明显残留，施用样各部位稀土总量比对照样增加约5％－10％，其分布模式与土壤类似；喷施的小麦样品的根、茎、叶中稀土残留严重，其含量比对照样高一个数量级，其分布模式与土壤及对照完全不同，表现为轻稀土更富集；3种施用方法的小麦籽粒中稀土残留均不明显。     

高瓦斯易自燃工作面高抽巷瓦斯抽采与采空区遗煤自燃相互影响研究

为了实现瓦斯与煤自燃两大灾害的联合防治,首先对布置高抽巷条件下瓦斯与遗煤自燃多因素相互影响关系进行了理论分析和归纳总结。结合淮南潘二煤矿11223高瓦斯易自燃工作面,建立了带有高抽巷的物理模型,利用UDF编译了本煤层与邻近层瓦斯涌出源项、采空区三维孔隙率和低温条件下煤氧化反应氧气消耗速率。在此基础上,分析了高抽巷布置参数和抽采参数以及工作面风量对高抽巷瓦斯抽采效果和采空区自燃带分布相互影响的规律。结果表明,当工作面风量为2 000 m3/min,高抽巷布置在顶板上方40 m时,高抽巷瓦斯抽采浓度和纯量分别达32.3%和29.07 m3/min,占总瓦斯涌出量的69.71%,同时能满足实际防火的要求。研究结果可为类似条件下高抽巷最佳施工与抽采参数提供借鉴。     

Treatment,residual chlorine and season as factors affecting variability of trihalomethanes in small drinking water systems

Seasonal variability in source water can lead to challenges for drinking water providers related to operational optimization and process control in treatment facilities. The objective of this study is to investigate seasonal variability of water quality in municipal small water systems (<3000 residents) supplied by surface waters. Residual chlorine and trihalomethanes (THM) were measured over seven years (2003–2009). Comparisons are made within each system over time, as well as between systems according to the type of their treatment technologies. THM concentrations are generally higher in the summer and autumn. The seasonal variability was generally more pronounced in systems using chlorination plus additional treatment. Chloroform, total THM (TTHM) and residual chlorine concentrations were generally lower in systems using chlorination plus additional treatment. Conversely, brominated THM concentrations were higher in systems using additional treatment. Residual chlorine was highest in the winter and lowest in the spring and summer. Seasonal variations were most pronounced for residual chlorine in systems with additional treatment. There was generally poor correlation between THM concentrations and concentrations of residual chlorine. Further study with these data will be beneficial in finding determinants and indicators for both quantity and variability of disinfection byproducts and other water quality parameters.     

轧钢污泥综合利用的技术研究

阐述了一种轧钢污泥的回收处理技术,该技术可把轧钢污泥有效地分离成氧化铁粉和混合油,实现综合利用,减少铁素资源浪费,有良好的经济效益和环境效益.