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51.
管道直饮水处理系统的优化设计探讨 总被引:1,自引:0,他引:1
对管道直饮水处理系统中的净水工艺和消毒方式的类型以及选择标准进行了详细探讨,并且对供水系统中的管网设计,饮水定额,以及管道材质和检测频率提出了参考性的建议。 相似文献
52.
This work is concerned with the dynamic modelling of the papermaking section of an integrated newsprint mill, and the subsequent application of two direct search methods in a proof-of-concept optimization study of broke recirculation strategies. The effect of the current broke recirculation policy on the mixed pulp properties at the paper machine headboxes was quantified using a dynamic simulation generating data for an objective function which reflected the rate of change in measurable (flow, consistency and temperature) and immeasurable (total dissolved solids and fibre length distribution) parameters. Genetic Algorithm and the Nelder–Mead simplex methods were then linked dynamically to the simulation and used to find improved ways of recirculating broke pulp. Specifically, the profile of the changes to the broke ratio was modelled using a quadratic function and a second-order transfer function, and the coefficients of these functions were optimized. The optimized broke recirculation resulted in a significant reduction in the value of the objective function, thus, suggesting that the fluctuations in the properties of the mixed pulp stream could be dampened and paper machine headbox stability improved. It is expected that this process enhancement strategy would contribute to an increase in production yield (via a reduction in the occurrence of paper machine breaks), and thus an overall reduction in the waste of materials and energy. 相似文献
53.
废旧塑料综合利用新方法——高炉喷吹废塑料技术 总被引:5,自引:0,他引:5
介绍了废旧塑料综合利用的新方法-高炉喷吹废料技术。通过比较,表明高喷吹废塑料技术在各方面均优于废旧塑料的其他处理方法;并简要对我国高炉喷吹废塑料作了可行性论证。 相似文献
54.
While chorionic villus sampling allows both early and rapid prenatal diagnosis of chromosome disorders, the accuracy of this technique has not been fully established. Maternal cell contamination and pseudomosaicism represent two major sources of diagnostic error. Combined use of both direct chromosome preparations and villus cultures is important in overcoming these problems. Direct preparations of villus tissue allow recognition of maternal cell contamination of villus cultures. Conversely, villus cultures yield higher resolution chromosomes and may be helpful in differentiating between true versus pseudomosaicism when two or more cell lines are identified in direct chromosome preparations. Preliminary data suggest that analysis of direct preparations from multiple individually processed villus fragments may also be of value in this regard. Until more experience is gained, mid-trimester amniocentesis should be offered to CVS patients when mosaicism is encountered. 相似文献
55.
Seher Basaran Peter Miny Ivar-Harry Pawlowitzki Jürgen Horst Wolfgang Holzgreve 《黑龙江环境通报》1988,8(4):315-320
Direct chromosome preparations were performed on placental villi obtained by ultrasoundguided needle aspiration between 18 and 37 weeks of pregnancy in 53 patients. The sampling yielded a sufficient amount of tissue with a maximum of two, and in most cases one, insertions. Placental biopsy is easily performed in cases of severe oligohydrammnios, where fetal blood sampling is usually more difficult. Direct karyotyping of placental villi is faster than chromosome analysis from fetal blood or application of the pipette method on amniotic fluid cells, and currently represents the most rapid approach to prenatal diagnosis of chromosomal abnormalities from the first to the third trimester of pregnancy. 相似文献
56.
通过应用FIA流动注射分析仪,成功进行水中挥发酚和氰化物的同时测定,测定数据准确、可靠、高效,大大缩短了测定时间,只需将两种标准配制成混合标样,一次取样完成两个项目的测定。回收率为93%~106%,相关系数达到0 9998以上。 相似文献
57.
Brominated flame retardants and heavy metals in automobile shredder residue (ASR) and their behavior in the melting process 总被引:3,自引:3,他引:0
Morihiro Osada Nobuhiro Tanigaki Shin Takahashi Shin-ichi Sakai 《Journal of Material Cycles and Waste Management》2008,10(2):93-101
The End-of-life Vehicles Recycling Act went into effect on January 1, 2005, in Japan and requires the proper treatment of
airbags, chlorofluorocarbons (CFCs), and automobile shredder residue (ASR). The need for optimal treatment and recycling of
ASR, in particular, has been increasing year after year because ASR is regarded as being difficult to treat. Dioxin-related
compounds, brominated flame retardants (BFRs), heavy metals, chlorine and organotin compounds are all present in high concentrations
in ASR. The authors conducted ASR melting treatment tests using a 10-tons/day-scale direct melting system (DMS), which employs
shaft-type gasification and melting technology. The results obtained showed that dioxin-related compounds and BFRs were decomposed
by this melting treatment. The high-temperature reducing atmosphere in the melting furnace moved volatile heavy metals such
as lead and zinc into the fly ash where they were distributed at a rate of more than 90% of the input amount. This treatment
was also found to be effective in the decomposition of organotin, with a rate of decomposition higher than 99.996% of the
input amount. Via the recovery of heavy metals concentrated in the fly ash, all the products discharged from this treatment
system were utilized effectively for the complete realization of an ASR recycling system that requires no final disposal sites. 相似文献
58.
The impact of direct and indirect experiences on the development of environmental knowledge, attitudes, and behavior 总被引:2,自引:0,他引:2
This study employed a mixed-methods design to examine the relationship between nature experience type (e.g., direct and indirect) and learning outcomes (e.g., environmental knowledge, attitudes, and behavior) associated with an environmental education, international immersion program for adolescents. Longitudinal data from 108 participant and 49 comparison group members were analyzed to test the study’s hypotheses. Additionally, qualitative data were analyzed using grounded theory methodology to assess participants’ perceptions of these processes. The findings indicate that environmental knowledge increased more than environmental attitudes during the indirect portion of the program (i.e., preparatory program) whereas the direct portion (i.e., international workshop) produced similar levels of knowledge and attitude growth. Further, while attitudes were more strongly associated with behavior during the indirect component of the program, the strength of the relationships between attitudes and behavior, and knowledge and behavior were similar during the direct portion of the experience. A synthesis of the findings suggests that the program’s direct experiences catalyzed environmental knowledge into a stronger motivating force than it had been during the indirect experiences. The qualitative findings also provide insights into the characteristics of direct experiences. These findings offer important insights for both theory and practice related to the use of direct and indirect nature experiences to develop environmental knowledge, attitude, and behaviors. 相似文献
59.
Forest fires have a significant economic, social, and environmental impact in Portugal. For that its fire risk was assessed through Bayes Formalism, where the main component of the risk of fire was assessed by the conditional probability of fire I(u,t) given a class of the daily severity rating (DSR) for a specific period of time—P[I(u,t)|R(u,t)]. The evaluation of this a posterior probability, P[I(u,t)|R(u,t)], was based on the update of marginal local probability of fire in each chosen region u (Durão, 2006).DSR values were used to calculate fire's risk, taking into account historical data, I(s,t), in a given region s, and also to define DSR's local thresholds in order to have P [I(u,t)|R(u,t)] ≥ 0.65.In this paper we characterize these posterior probabilities using direct sequential simulation models (DSS models) to obtain the spatial distribution of these probabilities over the entire Portugal, in order to assess the risk of fire and associated spatial uncertainty. Local probability density functions (pdfs) and spatial uncertainty are evaluated by a set of equiprobable simulated images of these posterior probabilities.Results are presented and discussed for the Portuguese fire seasons of the 2-year period, 2003-2004. The conditional probabilities reproduced reasonably well what was officially published for the studied fire seasons. We expect that a better understanding of both spatial and temporal patterns of fire in Portugal together with uncertainty measures constitutes an important tool for managers, helping to improve the effectiveness of fire prevention, detection and fire fighting resources allocation in critical social and environmental areas. 相似文献
60.