Comparing the sustainability of an innovative dry sanitation (Ecosan) system in China to a conventional waterborne sanitation system

The use of sustainability indicators for evaluating sanitation systems is applied to the Erdos Eco- Town Project (EETP) in China for illustration. The EETP is the largest urban settlement in the world employing ecological sanitation, which incorporates separation of waste streams, dry toilets, and resource recovery. The EETP’s dry sanitation system is compared against the Dongsheng District’s conventional sewer and centralised STP. The two systems are compared based on technological, environmental, economic, and societal indicators. Overall, the two systems perform reasonably well from a technological perspective. The conventional system performs significantly better than the dry system with regards to land and energy requirements, and global warming potential; it also performs better based on freshwater aquatic and terrestrial ecotoxicity potentials, but by a smaller margin. The dry system has superior environmental performance based on water consumption, eutrophication potential, and nutrient and organic matter recovery. The dry system is a more costly system as it requires greater infrastructure and higher operational costs, and does not benefit from economies of scale. The waterborne system performs better based on the societal indicators largely because it is a well-established system.

关于湍流中的相干结构

<正> 长期以来,湍流实验一直在影响着人们对湍流本质的认识。近十几年来,同湍流的理论研究相比,实验观测处于明显的领先地位。在剪切湍流的实验中,值得重视的一个进展是发现了一种准秩序的相干(Coherence)结构。这种结构包括大尺度间歇(intermittent)现象和猝发(burst)过程。它表明湍流不应再看作一种完全无秩序的运动。了解和深入研究这种准秩序的相干结构是非常吸引人的。它将有助于弄清楚湍流发生和发展的机制,从而促进对湍流研究的突破。本文主要是把国际上有关相干结构的研究概况做一简单评介。 在现代的实验中,曾经对发现相干结构起过重要作用的流场显示技术(如氢气泡技术),仍然一直被采用。热线风速仪虽然面临激光测速仪的挑战,但到目前为止,作为定量测量,还在广泛地应用着。其附属的数据处理系统,因电子技术和计算技术的飞跃发展,已得到很大的改进。值得注意的是

PICES Press, Vol. 8, No. 1, January 2000

The state of PICES science - 1999 The status of the Bering Sea: January - July, 1999 The state of the western North Pacific in the second half of 1998 The state of the eastern North Pacific since February 1999 MEQ/WG 8 Practical Workshop Michael M. Mullin - A biography Highlights of Eighth Annual Meeting Mechanism causing the variability of the Japanese sardine population: Achievements of the Bio-Cosmos Project in Japan Climate change, global warming, and the PICES mandate – The need for improved monitoring The new age of China-GLOBEC study GLOBEC activities in Korean waters Aspects of the Global Ocean Observing System (GOOS)

迎风紧致格式与热流计算

该文在朱庆勇、马延文(1998)一文的基础上给出了利用迎风紧致格式求解NS方程.它是UCGVC格式在粘性流计算中的推广.对于方程中的无粘部分利用Steger-Warming的通量分裂技术将流通向量分裂成两部分,在此基础上据风向构造逼近于无粘项的三阶迎风紧致格式.对方程中的粘性部分采用通常的二阶中心差分格式.该文利用对Burgers方程的特征分析,研究了为正确模拟边界层内的流动特征对网格雷诺数的限制条件.通过对超声速粘性球头绕流的数值模拟表明:迎风紧致格式能在较大的网格雷诺数的条件下计算热流值,结果是令人满意的.