改善温暖地区室内热环境的新途径——除湿

长江流域广大地区有夏闷热而冬阴冷的气候特征,过去以夏日通风隔热而冬日保温防寒的传统措施有一定效果,但不很显著,原因是尚未抓着主要矛盾,以此来改善环境未能收到理想功效。本文论证,以降低湿度以改善室内热环境这一新途径。这可能是湿热地区最为有效和最经济和节能的方法。     

A novel application of TPAD-MBR system to the pilot treatment of chemical synthesis-based pharmaceutical wastewater

A pilot-scale test was conducted with a two-phase anaerobic digestion (TPAD) system and a subsequential membrane bioreactor (MBR) treating chemical synthesis-based pharmaceutical wastewater. The TPAD system comprised a continuous stirred tank reactor (CSTR) and an upflow anaerobic sludge blanket-anaerobic filter (UASBAF), working as the acidogenic and methanogenic phases, respectively. The wastewater was high in COD, varying daily between 5789 and 58,792 mg L(-1), with a wide range of pH from 4.3 to 7.2. The wastewater was pumped at a fixed flow rate of 1m(3)h(-1) through the CSTR, the UASBAF and the MBR in series, resulting in respective HRTs of 12, 55 and 5h. Almost all the COD was removed by the TPAD-MBR system, leaving a COD of around 40 mg L(-1) in the MBR effluent. The pH of the MBR effluent was found in a narrow range of 6.8-7.6, indicating that the MBR effluent can be directly discharged into natural waters. A model, built on the back propagation neural network (BPNN) theory and linear regression techniques, was developed for the simulation of TPAD-MBR system performance in the biodegradation of chemical synthesis-based pharmaceutical wastewater. The model well fitted the laboratory data, and was able to simulate the removal of COD.     

Predictions of nitrate diffusion in sediment using horizontal attenuated total reflection (HATR) by Fourier transform infrared (FTIR) spectrometry

Using a novel and simple method based on horizontal attenuated total reflection (HATR) by Fourier transform infrared (FTIR) spectrometry, the effective diffusion coefficient, De, of nitrate in a contaminated anthropogenic sediment was estimated as 7.34 x 10(-6)cm2 s(-1). This method, which requires as little as 1 mL of sediment sample, was able to measure the De of a chemical species with a reproducibility of +/-3% in about 5h. Based on this De and a pre-determined nitrate reduction rate, the profiles of nitrate concentration in two sediment columns were satisfactorily predicted from a mathematical model. Results showed that the profile in this aged sediment depended mainly on the diffusion of nitrate and, only to a much lesser degree, the rate of nitrate reduction. Measurements in 55 anthropogenic sediment samples collected from five locations and various depths of a contaminated site further showed that the De of nitrate increased linearly with the water content of the sediment, but decreased with the sediment density. The technique demonstrated in this study shall be applicable for the risk assessment of toxic pollutants in contaminated sediments, and for planning the spatial and time intervals of nitrate injection strategy in bioremediation.     

历史街区保护与更新模式思考

本文通过对历史街区的认识以及城市设计在其保护与更新中的具体运用与原则,探索符合客观规律的历史街区保护与更新模式的多元选择。     

Effects of Air Inlet Configuration on Forced-Ventilation Enclosure Fires on a Naval Ship

The effects of air inlet configuration on pool fire behavior in a mechanically ventilated cabin were investigated. The closed cabin used was a model of a certain machinery cabin on a naval ship. Two air inlet configurations of one vent and two vents were taken into account together with five different elevations of air inlet. In one-vent cases, mass loss rate and gas temperature were lower and oxygen concentrations were higher than those of two-vent cases. With the increase of air inlet elevation, a sudden drop in average mass loss rate and peak temperature were found in the two-vent cases at the air inlet elevation of 1.56 m. In one-vent cases, a similar drop in average mass loss rate was found at the air inlet elevation of 0.88 m, while the peak temperature was almost unaffected by inlet elevation. According to temperature profiles and the characteristic parameter of the smoke layer stability, the formation of the smoke layer was destroyed by increasing the air inlet elevation or reducing the air inlets, and furthermore a more uniform distribution could be found. For the current cabin, the one-vent case with a lower air inlet elevation was recommended for smoke control, and the inlet should be set away from the essential equipment and the entrances of the cabin.     

Cobalt-Encapsulated in Nitrogen-Doped Carbon Nanotubes Prepared by Hydrothermal Method as Catalyst for Hydrogen Evolution

Abstract

Cobalt-encapsulated in nitrogen-doped carbon nanotubes (Co-NCNT) were prepared by hydrothermal method. CoCl₂·6H₂O and graphitic carbon nitride (g-C₃N₄) were used as raw material. Samples containing such defective structures were synthesized by hydrothermal methods, while there is an excellent synergistic effect between cobalt nanoparticles and carbon nanotubes on hydrogen evolution reaction (HER). In order to improving the HER performance, different samples were fabricated by changing the molar ratio of raw materials and pyrolysis temperature. The results show that Co-NCNT has the best HER performances at the ratio of CoCl₂·6H₂O and g-C₃N₄ (1:7) when the pyrolysis temperature reached 700?°C. The overpotential has reached 285?mV when the current density is 10?mA·cm^?2, the Tafel slope of the sample is 103?mV·dec^?1.     

关于建设海绵城市的思考

习近平总书记在中央城镇化工作会议上指出"城市规划建设的每个细节都要考虑对自然的影响,更不要打破自然系统。"为什么这么多城市缺水?一个重要原因就是水泥地太多,把能够涵养水源的林地、草地、湖泊、湿地给占用了,切断了自然的水循环,雨水来了,只能当作污水排走,地下水越抽越少。解决城市缺水问题,必须顺应自然。比如,在提升城市排水系统时要优先考虑把有限的雨水留下来,优先考虑更多利用自然力量排水,建设自然储存、自然渗透、自然     

金沙江乌东德水电站大坪地滑坡稳定性研究

介绍了大坪地滑坡区的地形地貌与地层岩性,阐述了该滑坡体的变形特征,结合大坪地滑坡的计算模型,分析了库水升降作用对滑坡稳定性的影响,该分析成果将对该库区的滑坡防治提供一定的参考。