Vertical variation in magnitude and partitioning of oxygen demand in a contaminated sediment

Antimicrobial resistance is a phenomenon of increasing importance. Sewage treatment processes are a vehicle for dissemination of resistant bacteria in both aquatic and terrestrial environments. To assess the number of antimicrobial resistant E. coli present in the wastewater inflow, effluent and sludge from urban sewage treatment plants in Portugal, 42 samples of crude inflow, treated effluent and sludge were collected in 14 municipal sewage treatment plants in Portugal. A total of 940 E. coli strains were recovered and tested, using the diffusion agar method, regarding their sensitivity to 12 different antimicrobial drugs. Resistance to tetracycline, ampicillin, trimethoprime/sulfamethoxazole, streptomycin and ciprofloxacin was found in 42.2, 32.6, 23.3, 26.4 and 11.9% of the isolates, respectively. No correlation was found with regards to medical antimicrobial use in Portugal. The highest resistance rates were found in E. coli strains isolated from the district capitals sampled. Wastewater treatment resulted in E. coli decrease between less than one log to four logs; nevertheless, an average of 1.17 × 10⁶ CFU/100 ml were present in the outflow of the plants. This investigation highlights the necessity for constant monitoring of the final effluent and sludge from these treatment facilities.     

多孔建筑材料热湿传递过程的研究

从理论计算和实验研究等方面对国内外多孔建筑材料的传热、传湿及热湿耦合传递研究方面的进展进行了综合分析。指出了目前多孔建筑材料热湿传递过程研究中存在的问题，并对未来的研究方向进行了展望。     

A study of coupled heat and mass transfer across a porous building component in intertropical conditions

In this paper, one-dimensional coupled heat and mass transfer through a plane geometry porous building component submitted to intertropical climatic conditions is studied. An analytical method using the periodic solution approach has been proposed to evaluate the heat and moisture transfer process in building materials. Results are discussed using the three climatic regions of Cameroon (2-13 °N). With latitude of 11°, it offers examples of practically whole range of intertropical climates. Influence of latitude on various temperature and moisture content through the building component has been presented. The results are in good agreement with the experimental data and other analytical solutions published in the literature.     

叉流除湿器中溶液与空气热质交换模型

建立了简化数学模型 ,空气出口温度和含湿量、溶液出口温度和质量分数的数值计算结果与实验结果的偏差在± 1 0 %以内 ,全热效率和除湿效率的偏差在± 2 0 %以内。通过分析除湿器内部温度场和浓度场得出 :在叉流除湿器中 ,不能忽略空气温湿度沿溶液流动方向和溶液温度沿空气流动方向的变化 ;传质驱动势要采用积分平均湿差的方法计算 ,而不能简单地采用对数平均湿差来表示     

溶液-湿空气热质交换过程的匹配研究

吸湿性溶液与空气的热质交换过程既有热量的交换又有质量的交换,提高该过程的可逆程度是提高溶液除湿空调系统性能的重要手段。在对溶液的性质进行合理简化的基础上,分析了溶液与空气的热质交换过程的流量比和过程需要吸收或释放的热量,得到在不同工况下,可逆过程所要求的流量比和应该补充或带走的热量。认为这一结论有助于溶液除湿空调流程的设计和相关参数的选取。