ALR-BAC组合工艺处理溴氨酸废水研究

采用气升式环流反应器(airlift loop reactor,ALR)-生物活性炭(biological activated carbon,BAC)组合工艺处理溴氨酸(bromoamine acid,BAA)废水.结果表明,以SBR方式运行的ALR,在保持进水溴氨酸浓度650 mg.L-1时,反应器稳定运行1个月,溴氨酸色度和COD去除率分别达到90%以上和50%左右,悬浮态菌沉降性能好;当进水溴氨酸浓度>200 mg.L-1时,其脱色产物继续曝气时极易发生自氧化而形成难以生物降解的黄色中间产物.后续的BAC处理体系可有效抑制溴氨酸脱色产物的自氧化,并使其不断被生物降解;当BAC体系中无外加硫酸盐时,Br-和SO42-的浓度随着进水COD的降低而不同程度地增加,最终Br-和SO42-的释放率分别达到72.2%和66.9%,COD去除率为85.7%.     

基于RBI的苯乙烯/环氧丙烷装置压力管道在线检验研究

对苯乙烯／环氧丙烷装置进行腐蚀回路划分,并将腐蚀回路中的压力管道按照管径、材质及用途等因素划分为不同的组别后进行RBI分析。根据风险评估结果,结合压力管道的使用情况、失效机理及剩余使用寿命等确定下一个检验周期和检验策略。以腐蚀回路中的组别作为检验单元,根据其失效可能性及风险等级确定各检验单元的检验比例和检验方法进行在线检验。结果表明：基于RBI分析结果的压力管道在线抽检方法可以验证风险评估的结果,同时还可以满足使用单位对管道的风险控制要求。     

Investigation of hit-and-run crash occurrence and severity using real-time loop detector data and hierarchical Bayesian binary logit model with random effects

Objective: Most of the extensive research dedicated to identifying the influential factors of hit-and-run (HR) crashes has utilized typical maximum likelihood estimation binary logit models, and none have employed real-time traffic data. To fill this gap, this study focused on investigating factors contributing to HR crashes, as well as the severity levels of HR.

Methods: This study analyzed 4-year crash and real-time loop detector data by employing hierarchical Bayesian models with random effects within a sequential logit structure. In addition to evaluation of the impact of random effects on model fitness and complexity, the prediction capability of the models was examined. Stepwise incremental sensitivity and specificity were calculated and receiver operating characteristic (ROC) curves were utilized to graphically illustrate the predictive performance of the model.

Results: Among the real-time flow variables, the average occupancy and speed from the upstream detector were observed to be positively correlated with HR crash possibility. The average upstream speed and speed difference between upstream and downstream speeds were correlated with the occurrence of severe HR crashes. In addition to real-time factors, other variables found influential for HR and severe HR crashes were length of segment, adverse weather conditions, dark lighting conditions with malfunctioning street lights, driving under the influence of alcohol, width of inner shoulder, and nighttime.

Conclusions: This study suggests the potential traffic conditions of HR and severe HR occurrence, which refer to relatively congested upstream traffic conditions with high upstream speed and significant speed deviations on long segments. The above findings suggest that traffic enforcement should be directed toward mitigating risky driving under the aforementioned traffic conditions. Moreover, enforcement agencies may employ alcohol checkpoints to counter driving under the influence (DUI) at night. With regard to engineering improvements, wider inner shoulders may be constructed to potentially reduce HR cases and street lights should be installed and maintained in working condition to make roads less prone to such crashes.     

Safety assessment for accident of cooling loop failure (ACLF) in lunar nuclear power reactor (LNPR)

The safety assessment of an accident in the lunar base power plant is investigated for the stability of the operation. The lunar surface reactor is modeled for this study. The accident of cooling loop failure (ACLF) is one of the important scenarios for the virtual case in the moon nuclear power plant (NPP). The newly designed lunar nuclear power reactor (LNPR) is suggested for the commercial purpose. The system dynamics (SD) is used for the simulation of the safety assessment. The cyclic variation of the lunar surface temperature can affect to the physical situation of the coolant, which is expressed by the time step. The result shows the performance possibility of the long term cooling increases slightly in the short period of the time step. The dynamical simulation of the lunar environment is performed for the conceptual design of the NPP.     

交流耦合法在砂尘试验设备浓度控制中的应用

采用了交流耦合技术中的浓度在线监测装置.简要介绍了砂尘浓度闭环控制的组成和结构,并对交流耦合法的特点和原理进行了分析和研究,指出了影响测量效果的环境因素.结合设备中应用的砂尘浓度测量闭环控制系统,说明了运用交流耦合法进行浓度测量的具体流程和操作方法.通过实际应用,验证了良好的控制效果,达到了预期的控制目的.     

气提式循环反应器生物膜与游离活性污泥处理污水的特点

介绍了气提式循环反应器处理污水中载体生物膜和游离活性污泥的对比试验研究 ,试验结果表明 :活性污泥有利于有机物的去除和混合液的沉降性 ;生物膜的存在 ,增加了生物量 ,提高了处理效率 ,而且是促进硝化作用的主要因素。     

基于危险源的事故致因机理及两极化管理

为提升安全风险预控的水平和有效性,探讨危险源的事故致因机理及其两极化管理思路。将危险源划分为3类,即根源危险源、理论状态危险源和实际状态危险源,其中理论状态危险源又可细分为已辨识状态危险源和未辨识状态危险源。构建危险源的事故致因机理模型,模型表明:控制失效的实际状态危险源和未辨识状态危险源是事故发生的2个主要致因。在此基础上,提出危险源的两极化管理思路,构建危险源两极化管理的实施流程。研究结论表明:企业应从两方面实施安全风险预控,即加强对实际状态危险源的控制,使其演变为事故致因的概率极小化;加强对根源危险源和理论状态危险源的辨识,做到辨识极大化。     

内循环三相生物流化床启动特性实验研究

本文分别考察了空气流量、水力停留时间、接种污泥浓度及微量元素等因素对内循环三相生物流化床反应器启动挂膜的影响。实验结果表明 ,0 .384L/ min的空气流量对生物膜的培养有利 ;低于 4小时的水力停留时间有利于启动挂膜 ;较少的接种污泥浓度有利于启动挂膜 ,快速排泥的方法能保证反应器启动成功 ;锌及镍等微量元素对反应器启动挂膜影响不大     

动态膜压法在长江口水域环境监测中的应用与前景探讨

根据近海海洋环境污染的特点和污染物的种类,对水体总有机污染物的监测与评价常采用CODCr、CODMn、BOD5等方法进行监测和评价,但这些监测方法本身易造成二次污染。本文根据有机物易趋向水体表面的特性,介绍一种无二次污染的动态膜压法监测技术用于长江口水域微表层的环境监测,该方法动态表面张力的滞回环面积与COD有较好的相关性。     

5MHz～20GHz低相位噪声频率源的研制

低相位噪声源是一种频率准确度、稳定度都很高且相位噪声又非常低的频率源.本文在简要着重描述了VCXO压控晶振锁相源、高频单元、低相位噪声微波倍频链、低噪声直流稳压电源等低相位噪声频率源关键部件的设计和研制过程.所研发的低相位噪声频率源的频率范围从5 MHz至20 C Hz点频输出,在100MHz频率时相噪达-176dBc...