AFB的活性污泥中发酵细菌的分离及其初步鉴定

从处理啤酒废水的厌氧流化床的活性污泥中分离纯化到了发酵细菌,并对其培养条件进行了研究,实验表明,该发酵细菌最佳培养温度为37～42℃,最佳培养时间为28 d,同时对其进行了生理生化和形态鉴定。将该发酵细菌反加到AFB反应器中,能有效降低反应器的启动时间,能提高反应器处理啤酒废水的处理效率约8%。     

Application of computational fluid dynamic to model the hydraulic performance of subsurface flow wetlands

A subsurface flow wetland(SSFW)was simulated using a commercial computational fluid dynamic(CFD)code.The constructed media was simulated using porous media and the liquid resident time distribution(RTD)in the SSFW was obtained using the particle trajectory model.The effect of wetland configuration and operating conditions on the hydraulic performance of the SSFW were investigated.The results indicated that the hydraulic performance of the SSFW was predominantly affected by the wetland configuration.The hydr...     

Optimization of dilution ventilation layout design in confined environments using Computational Fluid Dynamics (CFD)

Dilution ventilation systems have been widely used to control the airborne toxic and explosive material in confined spaces. Layout design of dilution ventilation is critical to industrial hygiene control and ventilation efficiency. A properly designed dilution ventilation system can significantly improve the safety of confined workshops and maintain a comfortable work condition. In this work, Computational Fluid Dynamics (CFD) has been used to analyze the performance of dilution ventilation system in the confined workshop environment. Seven different ventilation layouts are proposed to evaluate ventilation performance of different installation layouts. Carbon monoxide (CO), which has the similar density as air, is selected as the sample contaminant to conduct steady-state CFD simulations. The simulation results of different layouts are examined and compared to get the optimal layout design for the best contaminant control. Results have shown that the layout with two opposite inlets has the highest ventilation efficiency among seven proposed layouts. This work can serve as a reference to increase dilution ventilation efficiency and minimize the energy cost in general confined areas.     

淹没条件对连续射流破碎含瓦斯煤效率影响研究

为研究淹没条件对射流破煤效率的削弱程度,基于ALE算法,借助Ansys/Ls dyna模拟软件,建立围压状态下非淹没及淹没射流破碎含瓦斯煤体流固耦合模型,通过动态追踪破碎坑体单元失效演化过程及内部应力分布等瞬时信息,探讨2种射流状态下破煤成坑过程及破煤效率的差异。研究结果表明:淹没射流与非淹没射流两者破煤坑体形态差异显著,非淹没射流条件下射流破煤坑体断面较窄,深度较深,破煤效率前后阶段差别不大;淹没射流条件下射流破煤坑体断面较宽,深度较浅,在初始阶段形成漏斗状的破碎坑体,而后逐渐向下延伸,在0～100 μs内破煤效率最高;相同工况、同一时间内,淹没射流平均破煤深度是非淹没射流平均破煤深度的41.46%。研究结果可为水射流技术的现场应用提供参考依据。     

Application of Bayesian Regularization Artificial Neural Network in explosion risk analysis of fixed offshore platform

Computational Fluid Dynamics (CFD) is routinely used in Explosion Risk Analysis (ERA), as CFD-based ERA offers a good understanding of underlying physics accidental loads. Generally, simplifications were incorporated into CFD-based ERA to limit the number of simulations. Frozen Cloud Approach (FCA) is a frequently used simplification in the dispersion part of the CFD-based ERA procedure. However, its accuracy is questionable in the complex and congested environment such as offshore facility. Furthermore, in explosion part, some specific techniques, e.g. linear/double bin-interpolated techniques have been proposed while the corresponding accuracy is still unknown since the developers did not yet check their accuracy by considering the explosion computational data as the benchmark.This study presents a more accurate algorithm, namely Bayesian Regularization Artificial Neural Network (BRANN) and accordingly proposes the frameworks regarding BRANN-based models for the CFD-based ERA procedure. Firstly, the framework is proposed to develop the Transient-BRANN (TBRANN) model for transient dispersion study. In addition, the framework to determine the BRANN model for explosion study is developed. The proposed frameworks are explained by a case study of the fixed offshore platform. Consequently, this study confirms the more accuracy of the TBRANN model over FCA and the accuracy of BRANN model for CFD-based ERA.     

Computational fluid dynamics (CFD) study of heat radiation from large liquefied petroleum gas (LPG) pool fires

Liquefied petroleum gas (LPG) is flammable and has risks of pool fires during its transportation, storage, and applications. The heat radiation by LPG pool fires poses hazards to individuals nearby and can lead to potential failures of ambient facilities. Due to the high costs and invasive nature of experiments for investigating large-scale pool fires, computational fluid dynamics (CFD) is employed in this study as the cost-effective and noninvasive method to simulate the process and analyze the characteristics of large hydrocarbon pool fires. Specifically, an experimentally validated 3-D CFD model has been built to simulate surface emissive power (SEP) and incident radiation of large-scale LPG pool fires with three different diameters and wind speeds. Steady-state simulations with P1 radiation and probability density function (PDF) combustion models were employed to obtain reliable data after the optimizations based on the comparisons with experimental data and empirical models. The comparison with benchmark experimental data demonstrates that the CFD model employed in this study can accurately predict the incident radiation of large LPG pool fires. A new SEP correlation is also proposed, which is specifically for LPG pool fires with a diameter between 10 m and 20 m. Additionally, the safe separation distances between LPG facilities and surrounded objects have been estimated based on the CFD simulation results. The high-resolution CFD model for large LPG pool fires in this work provides noninvasive and direct quantitative evidence to enhance the fundamental understanding on the safety of large LPG pool fires and can assist regulatory agencies in refining the safety limits in the cost-effective and time-saving manners.     

Amniotic fluid acetylcholinesterase in the prenatal diagnosis of open neural tube defects and abdominal wall defects: A comparison of gel electrophoresis and a monoclonal antibody immunoassay

Stored amniotic fluid samples collected in Oxford and East Birmingham as part of the Collaborative Acetylcholinesterase Study were assayed for the presence of acetylcholinesterase (AChE) using a monoclonal antibody (4F19) enzyme antigen immunoassay. These results were compared with the results of a gel AChE which had been performed earlier. A total of 5689 samples from singleton pregnancies were analysed (including 36 with anencephaly, 77 with open spina bifida and 17 with anterior abdominal wall defects). The gel test yielded detection rates of 97% for anencephaly, 99% for open spina bifida and 94% for abdominal wall defects; the false positive rate (excluding pregnancies associated with serious abnormalities, miscarriages and intrauterine deaths) was 0·24%. The monoclonal test yielded similar results; using appropriate cut-off values to allow for differences in acetylcholinesterase levels in blood stained and clear samples, a similar false-positive rate of 0·22% was associated with detection rates of 97%, 95 % and 71 % respectively for the three types of defect. Although the detection rates and the false positive rate were slightly higher for the gel test, a result that might be explained by a decrease in AChE activity caused by storage of the samples, the monoclonal test has the advantages of requiring less interpretative expertise, it can be performed on a larger number of samples a day and it is not affected by contamination with fetal calf serum.     

Amniotic fluid alpha-fetoprotein,gamma-glutamyltranspeptidase,and autosomal trisomies

Alpha-fetoprotein (AFP) concentration and gamma-glutamyltranspeptidase (GGT) activity have been analysed in amniotic fluid from a series of 65 pregnancies with autosomal trisomies. AFP values were reduced on average to 60 per cent of normal in cases of trisomy 21, but were not significantly different from normal in cases of trisomies 18 and 13. GGT activities were uniformly lower (44 per cent of normal) for all types of autosomal trisomy. A review of the literature indicates that over 85 per cent of Down's pregnancies but only 39 per cent of trisomy 18 and 13 pregnancies have amniotic fluid AFP levels below the normal median value, while the corresponding figures for GGT are 91 per cent for Down's syndrome and 96 per cent for trisomies 18 and 13.     

乳化液的破乳与可生化性研究

根据混凝破乳处理乳化废液的实验参数，考察了混凝出水的可生化性。结果表明，ＰＢＴ混凝剂，具有良好的破乳效果，ＣＯＤｃｒ和油的平均去除率，分别达９０％与９９％以上，混凝出水ＢＯＤ５／ＣＯＤｃｒ可达０．４２－０．４６；间歇曝气实验及呼吸耗氧速率曲线表明，ＰＢＴ混凝出水，宜进行生化处理。     

油藏分隔性的地球化学研究

油藏的分隔性和油层连通性研究为油气成评价的重要内容，当前，油藏描述技术已经成为研究油层连通性的重要手段，但常规的油藏描述只着眼于储层的非均质性，主要研究储层的空间分布规律及其对油层连通性的影响。油藏地球化学研究成果表明，砂层连通体不一定等同于流体选通体，因为油层内可能存在有机隔层，出现“低层连通，油层分隔”的现象，利用地球化学方法可以直接研究油藏内部流体的非均质性，有效地判断油藏的分隔性。本文介绍了应用地球化学方法研究油藏分隔性的理论依据和研究方法，并介绍了几个北海油田的研究实例。