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761.
重庆长寿地区垂直温度结构特征分析 总被引:2,自引:0,他引:2
本文根据在长寿地区进行的一系列大气边界层探空试验资料,分析了大气温度垂直结构特征以及与逆温有关的大气扩散条件。 相似文献
762.
Wang Yayi Wang Shuying Peng Yongzhen Zhu Guibing Ling Yunfang 《Frontiers of Environmental Science & Engineering in China》2007,1(2):226-232
To supply the valuable operating parameters for the popular usage of the new denitrifying phosphors removal process, it is
essential to study the dominant biochemical reactions and the characteristics of denitrifying phosphorus removing bacteria
(DPB). Thus, parallel batch experiments using DPB sludge were carried out to assess the effect of substrates (sewage, HAc,
and endogenous carbon source) on denitrifying dephosphorus removal efficiency in this study. The results showed that the initial
specific phosphorus release rate increased with the high concentration of the short-chain volatile fatty acids ratio in the
influent, and sufficient phosphorus was released by DPB. This improved the subsequent denitrification and phosphorus uptake
efficiency. The specific endogenous denitrification mainly relies on the internal carbon source (PHB) stored by poly-P bacteria.
Denitrifying phosphorus removing bacteria were very hungry when the internal PHB was consumed. Consequently, the specific
endogenous denitrification rate was low and the phosphorus uptake did not happen. On the other hand, in the experiment, the
denitrifying phosphorus removal performance under two temperature conditions (8–10°C and 25–26°C) was also investigated and
analyzed. It was found that the lower temperature decreased the specific phosphorus release and uptake rate, but did not inhibit
the denitrifying phosphorus removal completely. Therefore, the negative influence of the low temperature on the overall phosphorus
removal was not significant.
Translated from Acta Scientiae Circumstantiae, 2006, 26 (2): 186–192 [译自: 环境科学学报] 相似文献
763.
广西东南部高温灾害气候特征分析 总被引:2,自引:0,他引:2
利用1953至2002年广西玉林市气温资料,统计分析了桂东南高温灾害天气气候特征,并概括出造成桂东南高温灾害天气的主要环流形势类型,总结出各种高温灾害天气环流形势的中短期预报方法和指标. 相似文献
764.
Stephen J. Gaffield Kenneth W. Potter Lizhu Wang 《Journal of the American Water Resources Association》2005,41(1):25-36
ABSTRACT: One of the biggest challenges in managing cold water streams in the Midwest is understanding how stream temperature is controlled by the complex interactions among meteorologic processes, channel geometry, and ground water inflow. Inflow of cold ground water, shade provided by riparian vegetation, and channel width are the most important factors controlling summer stream temperatures. A simple screening model was used to quantitatively evaluate the importance of these factors and guide management decisions. The model uses an analytical solution to the heat transport equation to predict steady‐state temperature throughout a stream reach. The model matches field data from four streams in southwestern Wisconsin quite well (typically within 1°C) and helps explain the observed warming and cooling trends along each stream reach. The distribution of ground water inflow throughout a stream reach has an important influence on stream temperature, and springs are especially effective at providing thermal refuge for fish. Although simple, this model provides insight into the importance of ground water and the impact different management strategies, such as planting trees to increase shade, may have on summer stream temperature. 相似文献
765.
Keith A. Cherkauer Stephen J. Burges Rebecca N. Handcock Jennifer E. Kay Stephanie K. Kampf Alan R. Gillespie 《Journal of the American Water Resources Association》2005,41(5):1149-1159
One central issue affecting the health of native fish species in the Pacific Northwest is water temperature. In situ observation methods monitor point temperatures, while thermal infrared (TIR) remote sensing captures spatial variations. Satellite‐based TIR sensors have the ability to view large regions in an instant. Four Pacific Northwest river reaches were selected to test the ability of both satellite‐based and moderate resolution aircraft‐based TIR remote sensing products to measure river temperatures. Images with resolutions of 5, 15, and 90 meters were compared with instream temperature observations to assess how along stream radiant temperatures are affected by resolution, reach width, and sensor platform. Where the stream reach can be resolved by the sensor, all sensors obtain water temperatures within ±2°C of instream observations. Along stream temperature variations of up to ±5°C were also observed. Trends were similar between two sets of TIR images taken several hours apart, indicating that the sensors are observing actual temperature patterns from the river surface. If sensor resolution is sufficient to obtain fully resolved water pixels in the river reach, accurate temperatures and spatial patterns can be observed. The current generation of satellite‐based TIR sensors is, however, only able to resolve about 6 percent of all Washington reaches listed as thermally impaired. 相似文献
766.
At one of the nitro-toluene facilities, an o-nitro toluene still was in standby mode. During the standby mode feed to the still had been stopped, the column was not de-inventoried, steam flow to the reboiler was not shut off and the condenser was on total reflux. After 22 days of standby mode, steam was shut off for 5 days for annual plant maintenance. Eight days after the re-start of steam, the still exploded, hurling debris as far as one mile. The internal packing was expelled from the column and landed on the ground burning. The incident was investigated to establish the contributing factors leading to explosion. Accelerating Rate Calorimetery was extensively used to determine the onset temperature for exothermic activity in the presence/absence of a number of materials to establish the underlying cause of the accident. It was found that foulant collected in the column over a period of years accelerated the ’runaway reaction’. 相似文献
767.
针对寒冷地区建筑物的采暖方式,介绍一种新型的区域供暖方式--地温水源热泵(地温中央空调)供暖系统,为寻找新型供暖方式提出了环保安全、绿色节参采暖制冷新理念。 相似文献
768.
Peter M. Kiffney Jennifer P. Bull Michael C. Feller 《Journal of the American Water Resources Association》2002,38(5):1437-1451
ABSTRACT: Climate data from the Malcolm Knapp Research Forest (MKRF) in the Coast Range mountains of southwestern British Columbia were used to examine relationships between climate and hydrology and variations in the El Niño Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO). Air and water temperatures were higher and precipitation was lower during in‐phase or warm PDO/E1 Niño events than in other years. In contrast, in‐phase or cool PDO/La Niña years were generally cooler and wetter than other years. Precipitation and East Creek discharge were positively related to the Southern Oscillation Index (SOI) and negatively related to the PDO index. Conversely, air and water temperatures were negatively related to the SOI and positively related to the PDO index. Differences in precipitation and air temperature were also evident at longer time scales when separated by PDO phase. Because of drier conditions during in‐phase El Niño events, the flow of organic matter from East Creek to downstream portions of the channel network was lower compared to other years. This reduction has implications for downstream communities, as these subsidies provide a major source of energy for stream food webs. Therefore, short term and long term shifts in climate, discharge, and water temperature may have profound impacts on the ecology of Pacific Northwest (PNW) watersheds due to changes in a number of ecosystem processes such as altered flux of organic matter from headwater streams to larger rivers. 相似文献
769.
770.