Markov reliability model research of monitoring process in digital main control room of nuclear power plant

Monitoring process is an important part in a high safety digital main control room of nuclear power plant (NPP), it is the source extracted information and found abnormal information in time. As the human factors events arisen from monitoring process recently take place more and more frequent, the authors propose a reliability Markov model to effectively decrease these abnormal events. The model mainly analyzes next monitoring object probability in terms of current information and plant state. The authors divide digital human–machine interface into two parts that are referred as logical homogeneous Markov and logical heterogeneous Markov. For the former, a series of methods of probability evaluation are proposed, such as, Markov transition probability with condition, probability distributed function with human factors, system state and alarm; for the latter, the authors propose the calculation of probability of correlation degree between last time and next time and probability calculation methods with multi-father nodes. The methods can effectively estimate the transition probability from a monitoring component to next monitoring component at time t, can effectively analyze which information is more important in next monitoring process and effectively find more useful information in time t + 1, so that the human factors events in monitoring process can greatly be decreased.     

系统工程方法建设应急救援平台的探讨

功能全面、实用高效的应急救援平台是实施科学、有效的应急救援的基础之一,也是一个复杂的人、机、信息综合系统,系统工程的分析方法及思想对指导应急救援平台的建设具有较强的针对性和指导意义.在分析了国内外应急救援平台的现状并明确了其功能、要求后,运用系统工程方法从应急救援方式、设备、人员、信息系统、移动平台5个方面进行了分析和...     

Using FeGAC/H2O2 process for landfill leachate treatment

Due to the growing concern of highly contaminated landfill leachate problems in Taiwan, an innovative advanced catalytic oxidation (FeGAC/H(2)O(2)) process was developed and employed in this research to treat the landfill leachate from central Taiwan. Experimental results indicated that the FeGAC/H(2)O(2) process could effectively remove organic compounds from landfill leachate. The presence of iron oxide coated granular activated carbon (FeGAC) greatly improved the oxidative ability of H(2)O(2) for the removal of humic acids, fulvic acids and non-humic substance from leachate. For instance, at pH 6, the removal efficiencies of FeGAC/H(2)O(2) and H(2)O(2) processes were 70% and 8%, respectively. FeGAC/H(2)O(2) combined both advantages of FeGAC and H(2)O(2) where FeGAC had good organics adsorption ability and could effectively catalyse the hydrogen peroxide oxidation reaction for organics removal.     

Isolation and characterization of 1,2,4-trichlorobenzene mineralizing Bordetella sp. and its bioremediation potential in soil

A soil which has been polluted with chlorinated benzenes for more than 25 years was used for isolation of adapted microorganisms able to mineralize 1,2,4-trichlorobenzene (1,2,4-TCB). A microbial community was enriched from this soil and acclimated in liquid culture under aerobic conditions using 1,2,4-TCB as a sole available carbon source. From this community, two strains were isolated and identified by comparative sequence analysis of their 16S-rRNA coding genes as members of the genus Bordetella with Bordetella sp. QJ2-5 as the highest homological strain and with Bordetella petrii as the closest related described species. The 16S-rDNA of the two isolated strains showed a similarity of 100%. These strains were able to mineralize 1,2,4-TCB within two weeks to approximately 50% in liquid culture experiments. One of these strains was reinoculated to an agricultural soil with low native 1,2,4-TCB degradation capacity to investigate its bioremediation potential. The reinoculated strain kept its biodegradation capability: (14)C-labeled 1,2,4-TCB applied to this inoculated soil was mineralized to about 40% within one month of incubation. This indicates a possible application of the isolated Bordetella sp. for bioremediation of 1,2,4-TCB contaminated sites.     

Bioavailability to grains of rice of aged and fresh DDD and DDE in soils

DDT had been widely used around the world before 1980s and is still under production and use for non-agricultural purposes in China. Because of their special physicochemical properties, p,p'-DDT and its main metabolites, p,p'-DDD and p,p'-DDE, accumulated and persisted in the environment, presenting potential menace on biota. A green-house study was conducted to determine the bioavailability of p,p'-DDD and p,p'-DDE to grains of rice and the influences of traditional Chinese farming practices on their bioaccumulation. Paddy rice and dry rice were grown in submerged paddy soils and non-submerged upland soils, respectively. Two types of soil, Hydragric Anthrosols (An) and Hydragric Acrisols (Ac), were employed. Bioaccumulation factors (BAFs) of DDE ranged from 0.67 for rice grown in non-submerged An to 0.84 in submerged An in the control group, whilst BAFs were all below 0.04 in experimental groups. BAFs of DDD varied from 1.39 for submerged An to 2.26 for submerged Ac in original soils. In contrast, BAFs were between 0.05 for non-submerged Ac and 0.08 for submerged An in DDD-contaminated soils. Flooding seemed to have two contradictory effects on the DDE/DDD accumulation by rice: on one hand, it made the pollutants more mobile and bioavailable; while on the other hand, it enhanced the degradation and binding of POPs. Adding rice straw to the soils protected DDE from being taken up yet promoted DDD accumulation by rice. Furthermore, the distinct inorganic component of the soils might also play an important role in the environmental activities of POPs.     

污水厂Carrousel氧化沟溶解氧和速度分布的研究

对长沙某污水处理厂的Carrousel氧化沟进行现场测试，获得不同截面的溶解氧和速度的数据，探讨了表曝机台数、沟深、沟的长宽比、进出水位置对溶解氧和速度的影响。初步掌握了该Carrousel氧化沟内溶解氧和速度的变化规律，认为通过调节倒伞形表面曝气机，可以在沟内不同区段创造好氧与缺氧的环境，为最终实现同步硝化反硝化的高效运行做准备。     

海洋柴油溢油油水快速分离的应用研究

针对海洋柴油溢油,采用破乳剂对油水快速分离进行了研究.分别对油水比、温度、破乳剂量及存在Ca2 、Mg2 的影响因素,进行了系列油水快速分离试验,并测定了破乳剂作用下乳液的界面张力.试验结果表明,柴油溢油形成的乳液稳定性较差,油水分离较容易,但分离后的水中含油量较高.加入聚醚类非离子型破乳剂FA、FB、FC和FD,可达到油水低温、快速分离的目的,且分离后的水中含油量较低.随着破乳剂浓度的增加,界面张力降低,当破乳剂浓度达到临界胶束浓度(CMC)时,界面张力最小,脱水效果最好.Ca2 、Mg2 对聚醚类非离子型破乳剂的影响很小.     

ClO2三相催化氧化处理硝基苯生产废水的试验

硝基苯(NB)生产废水中含有大量NB及其衍生物,对生物具有毒性,属难生物降解物质.采用ClO2三相催化氧化工艺对NB废水进行处理.结果表明,每升废水投加280、350 mg ClO2,废水在活性炭加载含铜复合金属氧化物的催化剂床层停留56min,NB和色度的去除率均达到95%以上,COD去除率达到90%以上.吨废水处理成本约为10.5元.     

Effects of seasonal succession and water pollution on the protozoan community structure in an eutrophic lake

The purpose of the research is to study the seasonal succession of protozoa community and the effect of water quality on the protozoa community to characterize biochemical processes occurring at a eutrophic Lake Donghu, a large shallow lake in Wuhan City, China. Samples of protozoa communities were obtained monthly at three stations by PFU (polyurethane foam unit) method over a year. Synchronously, water samples also were taken from the stations for the water chemical quality analysis. Six major variables were examined in a principal component analysis (PCA), which indicate the fast changes of water quality in this station I and less within-year variation and a comparatively stable water quality in stations II and III. The community data were analyzed using multivariate techniques, and we show that clusters are rather mixed and poorly separated, suggesting that the community structure is changing gradually, giving a slight merging of clusters form the summer to the autumn and the autumn to the winter. Canonical correspondence analysis (CCA) was used to infer the relationship between water quality variables and phytoplankton community structure, which changed substantially over the survey period. From the analysis of cluster and CCA, coupled by community pollution value (CPV), it is concluded that the key factors driving the change in protozoa community composition in Lake Donghu was water qualities rather than seasons.     

Use of chemical coagulants to control fouling potential for wastewater membrane bioreactor processes.

Chemical coagulation with ferric chloride, alum, and an organic polymer were used to control the fouling potential of mixed liquors for submerged membrane bioreactor (MBR) processes in treating municipal wastewater. Their filterability was evaluated using a submerged hollow fiber ultrafiltration apparatus operated in constant permeate flux mode. The collected transmembrane pressures over filtration time were used to calculate the membrane fouling rates. The results showed that coagulation pretreatment can reduce fouling rates when MBRs were operated above the critical flux. Even though coagulation with the organic polymer formed larger mixed liquor suspended solids particles and had shorter time-to-filtration than those with ferric chloride and alum, the filterability for membrane filtration were similar, indicating that the membrane fouling in MBR systems was mainly controlled by the concentration of smaller colloidal particles.