某污水处理厂活性污泥沉降脱水性能的研究

以污泥沉降特性的参数及各参数之间的规律为研究目标,结果表明当活性污泥的SVI和MLSS分别在110-150,1500-2000mg/L时,污泥沉降速度在2-6min内有很明显的峰值,污泥界面高度变化明显.且在维持污泥沉降性能的前提下,随着污泥SVI(污泥指数)的增大,污泥的MLSS(污泥浓度)值呈递减趋势.具有相同污泥...     

乌鲁木齐市大气环境质量变化趋势分析

以乌鲁木齐市2004～2010年间的大气环境质量监测数据为依据,采用空气污染综合指数法评价其大气环境质量,并运用Spearman秩相关系数预测其发展趋势.结果表明:乌鲁木齐市大气环境质量为轻度污染,主要污染物为SO2和PM10.NO2和PM10有上升趋势,SO2呈不显著下降趋势.     

滇池流域TN、TP入湖负荷预报预警系统

以流域模型HSPF和贝叶斯递归回归树算法(BRRT)为计算模块,建立了滇池流域27条主要入湖河流和33个散流区的TN、TP入湖负荷预报预警系统.同时,构建了考虑历史排放规律和预测负荷计算预警指数(EWI)评价预警等级的两套预警体系.结果表明:BRRT替代模型在流域内以农业面源为主的柴河子流域校准和验证的可决系数R2均大于0.8,模拟结果相对可靠;根据预警时间选取预警体系;适用于6月份之前的预警体系一(EWS-1),利用现状排放量和历史排放量的关系计算预警指数.适用于6月份之后的预警体系二(EWS-2),主要考虑现状排放量、历史平均排放量、排放限值和预测排放量之间的关系计算3个预警指数,最终以最严格的作为综合预警指数EWI评价预警等级;根据柴河子流域"十二五"规划的TN和TP排放限值为130.2 t·a-1、6.8 t·a-1,应用此系统对2011年2、4、9和11月做出预警检验,各月份预警结果基本处于红色和黑色预警,该系统可为流域提供预警支持.     

基于人类可持续发展指数的中国1990—2010年人类-环境系统可持续性评价

中国经济的快速发展对人类-环境系统造成了巨大压力。如何全面地评估中国人类-环境系统可持续性已成为当前可持续性科学的一个研究热点。论文基于"人类可持续发展指数"在国家、区域和省三个尺度上系统评价了中国人类-环境系统1990—2010年的可持续性。研究结果表明,2010年中国人类-环境系统可持续性为中上水平,总体呈现东高西低的空间格局。1990—2010年中国人类-环境系统可持续性表现为增长趋势,中西部可持续性增长快于东部。经济和社会可持续性指标呈增加趋势,环境可持续性指标为下降趋势。可见,中国人类-环境系统可持续性的空间格局与动态变化均不协调,需进一步促进中西部社会经济发展及加强生态文明建设以实现社会、经济与环境可持续性的全面提高。     

Preoptimal analysis of phase characteristic indicators in the entire process of coal spontaneous combustion

To accurately predict the development degree of coal spontaneous combustion (CSC), the CSC process was investigated using a programmed high-temperature-heating experimental system, and the variation law of index gas concentration in the holistic process of CSC and oxidation is formulated. Additionally, the accuracy of the experimental system was evaluated using experimental design for thermal analysis, and the correlation between gas index and apparent activation energy was determined using grey correlation analysis. The results indicated the following. In the critical temperature stage (0–100 °C), φ(CO)/φ(CO₂) should serve as the main index and C₂H₄ should serve as the auxiliary index; in the crack-active-speedup temperature stage (100–260 °C), CO and φ(C₂H₄)/φ(C₂H₆) should serve as the main index and R₁, the Graham index, and φ(C₂H₄)/φ(CH₄) should serve as auxiliary indexes; in the speedup-ignition temperature stage (260–370 °C), R₂ and the Graham index should serve as main indexes and φ(CO)/φ(CO₂), C₂H₄, and R₁ should serve as auxiliary indexes; in the ignition temperature (370–500 °C), R₃ should serve as the main index and R₂, the Graham index and C₂H₄ should serve as auxiliary indexes. Among them, the grey correlation degrees among the Graham index, Grignard fire coefficient, and apparent activation energy were the highest, reaching 0.91.     

Effects of different management strategies on long-term trends of Australian threatened and near-threatened mammals

Monitoring is critical to assess management effectiveness, but broadscale systematic assessments of monitoring to evaluate and improve recovery efforts are lacking. We compiled 1808 time series from 71 threatened and near-threatened terrestrial and volant mammal species and subspecies in Australia (48% of all threatened mammal taxa) to compare relative trends of populations subject to different management strategies. We adapted the Living Planet Index to develop the Threatened Species Index for Australian Mammals and track aggregate trends for all sampled threatened mammal populations and for small (<35 g), medium (35–5500 g), and large mammals (>5500 g) from 2000 to 2017. Unmanaged populations (42 taxa) declined by 63% on average; unmanaged small mammals exhibited the greatest declines (96%). Populations of 17 taxa in havens (islands and fenced areas that excluded or eliminated introduced red foxes [Vulpes vulpes] and domestic cats [Felis catus]) increased by 680%. Outside havens, populations undergoing sustained predator baiting initially declined by 75% but subsequently increased to 47% of their abundance in 2000. At sites where predators were not excluded or baited but other actions (e.g., fire management, introduced herbivore control) occurred, populations of small and medium mammals declined faster, but large mammals declined more slowly, than unmanaged populations. Only 13% of taxa had data for both unmanaged and managed populations; index comparisons for this subset showed that taxa with populations increasing inside havens declined outside havens but taxa with populations subject to predator baiting outside havens declined more slowly than populations with no management and then increased, whereas unmanaged populations continued to decline. More comprehensive and improved monitoring (particularly encompassing poorly represented management actions and taxonomic groups like bats and small mammals) is required to understand whether and where management has worked. Improved implementation of management for threats other than predation is critical to recover Australia's threatened mammals.     

Revealing the socioeconomic impact of small disasters in Colombia using the DesInventar database

Small disasters are usually the product of climate variability and climate change. Analysis of them illustrates that they increase difficulties for local development—frequently affecting the livelihoods of poor people and perpetuating their level of poverty and human insecurity—and entail challenges for a country's development. In contrast to extreme events, small disasters are often invisible at the national level and their effects are not considered as relevant from a macroeconomic standpoint. Nevertheless, their accumulated impact causes economic, environmental and social problems. This paper presents the results of an evaluation of the DesInventar database, developed in 1994 by the Network for Social Studies in Disaster Prevention in Latin America. In addition, it proposes a new version of the Local Disaster Index developed in 2005 within the framework of the Disaster Risk and Management Indicators Program for the Americas, with the support of the Inter‐American Development Bank.     

潮白河密云水库流域自然景观的分级和评价

应用卫星遥感技术对潮白河密云水库流域的自然景观进行了自然度分级,并利用景观自然度指数、景观退化程度指数和景观重建程度指数对自然景观进行了评价。结果是研究区景观中度退化,重建程度中等,呈半自然状态。区内景观状态的优劣顺序为:兴隆、怀柔、密云、延庆、滦平、丰宁、崇礼、赤城、沽源。      

月径流时间序列的混沌特性分析

研究根据混沌理论,分别采用功率谱分析方法、G-P关联维识别合水水库月径流量的混沌特性,并且得出主要的混沌特性指标.以Tanks嵌入定理为理论基础,进行短期预测,能够取得精度较高的预测结果.研究表明:月径流序列存在一定的混沌特性,其最小嵌入维数在m=8对应的吸引子维数D=-0.95,最大李雅谱诺夫指数σ=0.325,采用加权一阶权域方法预测时,预测最大时限为4个月,其预测精度均在5%以内.     

沈阳市建设生态城市指标及对策研究

通过研究生态城市的指标及沈阳市城市生态指标的现状值 ,将每项指标的现状值与目标值进行比较 ,并分析造成沈阳市生态城市建设现状值与目标值差距的原因 ,然后提出了沈阳市创建生态城市的对策。