资源型城市复杂因素耦合的系统动力学分析

针对煤炭型资源城市转型及其如何可持续发展问题,建立了资源型城市系统动力学模型,该模型主要由人口、经济、资源以及环境4部分耦合组成,通过调整煤炭回采率等9个控制变量,进而预测了城市的4种发展情景;最后,以抚顺市为例,验证了模型的真实性。研究表明,资源型城市是人口、经济、资源和环境等因素耦合的复杂系统;该资源型城市系统动力学模型的平均相对误差在8%以内;综合分析各种发展情景,情景Ⅳ在人口、经济、资源和环境方面均具有较好的综合表现;预计到2015年该情景下,抚顺市人口总量、工业和服务业增加值、耕地面积、原煤资源总量、废气污染量分别将达到219.536万人、1103.310亿元、788.813亿元、89 579 hm²、1926亿t以及8.321×102、1926亿t以及8.321×10⁷万Nm7万Nm³。     

磁性纳米氢氧化锆对硫酸根吸附特性研究

以纳米四氧化三铁、氧氯化锆和氨水为原料,用溶胶凝胶法合成了磁性纳米氢氧化锆。通过静态吸附试验研究磁性纳米氢氧化锆对硫酸根的吸附性能。考察了溶液初始pH、吸附剂投加量、温度等因素对吸附效果的影响。结果表明:pH是影响吸附的重要因素,适宜的pH为1~2。吸附容量、去除率均随投加量增大而增大,之后去除率趋于平衡。磁性纳米氢氧化锆对硫酸根吸附过程符合Langmuir单分子层模型。对热力学参数ΔG0、ΔH0、ΔS0进行分析,表明磁性纳米氢氧化锆对硫酸根的吸附为吸热、熵值增加的自发过程。动力学分析表明,准二级动力学模型能更准确地拟合动力学过程。对吸附饱和的磁性纳米氢氧化锆进行脱附和再吸附,脱附率可达90%,再吸附容量为90 mg/g,表明磁性纳米氢氧化锆是一种磁分离性能良好的可以重复利用的硫酸根吸附剂。     

广州市工业低碳化转型升级研究

利用系统动力学模型,结合情景分析法,对广州市2012年-2020年工业二氧化碳排放产生量进行模拟预测.通过调整广州市产业结构、科技投入水平、能源结构三个影响因子,设置三种情景模式,并模拟预测广州市工业二氧化碳排放量情况,通过对比分析发现三种情景都不能达到广州市2020年减排目标,在此基础上,结合广州市工业发展的实际情况,进一步调整三个影响因子参数,提出适合广州市工业发展的调整情景模式,从而根据研究提出广州市工业低碳化转型升级的对策措施及实施路径.     

复合释氧剂的制备及其对水体修复的作用

采用腐殖酸钠、过氧化钙和沸石为原材料,在一定条件下制备复合释氧剂用于黑臭水体的生态修复。研究结果表明,复合释氧剂最佳制备条件为m(CaO_2)∶m(沸石)为1∶1、Na-A质量分数为2%和固化温度为100℃,复合释氧剂可显著延长释氧周期,且释氧过程对水体pH和COD的影响极低;底泥修复实验结果显示,复合释氧剂投加量为560 g/m~2时,上覆水溶解氧和氧化还原电位在第30天时分别维持在1.32 mg/L及42 m V,水中TP和COD去除率可分别达到90.11%和63%,表明复合释氧剂可有效改善水质并抑制底泥磷释放,这对城镇黑臭水体的生态修复治理具有一定的实际意义。     

Soil and Water Characteristics in Restored Canebrake and Forest Riparian Zones1

Andrews, Danielle M., Christopher D. Barton, Randall K. Kolka, Charles C. Rhoades, and Adam J. Dattilo, 2011. Soil and Water Characteristics in Restored Canebrake and Forest Riparian Zones. Journal of the American Water Resources Association (JAWRA) 47(4):772‐784. DOI: 10.1111/j.1752‐1688.2011.00555.x Abstract: The degradation of streams has been widespread in the United States. In Kentucky, for instance, almost all of its large streams have been impounded or channelized. A restoration project was initiated in a channelized section of Wilson Creek (Nelson Co., Kentucky) to return its predisturbance meandering configuration. A goal of the project was to restore the native riparian corridor with giant cane and bottomland forest species. The objective of this study was to evaluate the use of giant cane in riparian restoration and to compare water quality and soil attributes between restored cane and forested communities. Comparison of data to replicated sites of similar size in undisturbed upstream areas (control) was also examined to evaluate restoration success. Vegetation establishment was initially hindered by frequent flooding in 2004, but mean survival was good after two growing seasons with rates of 80 and 61% for forest and cane plots, respectively. Results showed an improvement in stream water quality due to restoration activities. Significant differences between the cane and forested plots in shallow groundwater dissolved oxygen, NO₃^?‐N, NH₄⁺‐N, and Mn concentrations suggest that soil redox conditions were not similar between the two vegetation types. Retention and transformation of carbon (C) and nitrogen (N) within the restored riparian system also differed by vegetation treatment; however, both communities appeared to be advancing toward conditions exhibited in the control section of Wilson Creek.     

Improved Bankfull Channel Geometry Prediction Using Two‐Year Return‐Period Discharge1

He, Laien and Gregory V. Wilkerson, 2011. Improved Bankfull Channel Geometry Prediction Using Two‐Year Return‐Period Discharge. Journal of the American Water Resources Association (JAWRA) 47(6):1298–1316. DOI: 10.1111/j.1752‐1688.2011.00567.x Abstract:  Bankfull discharge (Q_bf) and bankfull channel geometry (i.e., width, W_bf; mean depth, D_bf; and cross‐section area, A_bf) are important design parameters in stream restoration, habitat creation, mined land reclamation, and related projects. The selection of values for these parameters is facilitated by regional curves (regression models in which Q_bf, W_bf, D_bf, and A_bf are predicted as a function of drainage area, A_da). This paper explores the potential for the two‐year return‐period discharge (Q₂) to improve predictions of W_bf, D_bf, and A_bf. Improved predictions are expected because Q₂ estimates integrate the effects of basin drainage area, climate, and geology. For conducting this study, 29 datasets (each representing one hydrologic region) spanning 14 states in the United States were analyzed. We assessed the utility of using Q₂ by comparing statistical measures of regression model performance (e.g., coefficient of determination and Akaike’s information criterion). Compared to using A_da, Q₂ is shown to be a “clearly superior” predictor of W_bf, D_bf, and A_bf, respectively, for 21, 13, and 25% of the datasets. By contrast, A_da yielded a clearly superior model for predicting W_bf, D_bf, and A_bf, respectively, for 0, 0, and 14% of the datasets. Our conclusion is that it alongside with developing conventional regional curves using A_da it is prudent to develop regional curves that use Q₂ as an independent variable because in some cases the resulting model will be superior.     

地铁车站客流流动机理研究与应用

为制定有效的地铁车站客流疏导方案及应急疏散预案,通过现场观测,结合录制的视频资料,分析人员流动的基本特点,提出人员流动类似于气体和液体的流动的现象,建立人员流守恒方程和流体动力学的连续模型,提出基于流体动力学的人员疏散理论模型。采用建立的数学模型和数值算法,开发了紧急疏散计算分析软件V1.0,对地铁车站站台的人员进行数值模拟分析,通过模拟结果与实际观测情况进行对比发现,模拟结果与实际观测情况基本相符,即车站站台上行楼梯口处为乘客拥堵的节点,并呈现客流叠加的现象。     

城市重大危机事件演化的动力学模型研究

建立了城市重大危机事件的＂事件链＂,并分析了＂事件链＂中各状态的相互关系。基于SEIS传染病模型的思想,提出了一类城市重大危机事件的动力学模型。分别在不考虑外部因素对事件链的影响和考虑外部因素对事件链的影响的情况下,对事件从正常状态到危机状态沿时间的发展趋势和规律进行了分析,并对解进行Lyapunov稳定性分析以及计算机模拟仿真。研究表明：系统自身的修复能力和外部因素对系统的影响是控制危机事件的重要因素。     

Open rivers: barrier removal planning and the restoration of free-flowing rivers

Restoration of unobstructed, free-flowing sections of river can provide considerable environmental and ecological benefits. It removes impediments to aquatic species dispersal and improves flow, sediment and nutrient transport. This, in turn, can serve to improve environmental quality and abundance of native species, not only within the river channel itself, but also within adjacent riparian, floodplain and coastal areas. In support of this effort, a generic optimization model is presented in this paper for prioritizing the removal of problematic structures, which adversely affect aquatic species dispersal and river hydrology. Its purpose is to maximize, subject to a budget, the size of the single largest section of connected river unimpeded by artificial flow and dispersal barriers. The model is designed to improve, in a holistic way, the connectivity and environmental status of a river network. Furthermore, unlike most previous prioritization methods, it is particularly well suited to meet the needs of potamodromous fish species and other resident aquatic organisms, which regularly disperse among different parts of a river network. After presenting an initial mixed integer linear programming formulation of the model, more scalable reformulation and solution techniques are investigated for solving large, realistic-sized instances. Results from a case-study of the Pike River Watershed, located in northeast Wisconsin, USA, demonstrate the computational efficiency of the proposed model as well as highlight some general insights about systematic barrier removal planning.     

Validation of a multispecies forest dynamics model using 50-year growth from Eucalyptus forests in eastern Australia

One of the key problems confronting ecological forecasting is the validation of computer models. Here we report successful validation of a forest dynamics model Ecosystem Dynamics Simulator (EDS), adapted from the JABOWA-II forest succession model. This model and many variants derived from it have successfully simulated growth dynamics of uneven-aged mixed forests under changing environment with a moderate amount of input data. But rarely are adequate time-series data available for quantitative model validation. This study tested the performance of EDS in projecting the tree density, tree diameter at breast height (dbh), tree height, basal area and aboveground biomass of uneven-aged, mixed species sclerophyll forests in St. Mary state forests of eastern Australia. The test data were collected between 1951 and 2005. Every tree was uniquely numbered, tagged and measured in consecutive re-measurements. Projected growth attributes were compared with those observed in an independent validation dataset. The model produced satisfactory projections of tree density (91.7%), dbh (92.3%), total tree height (82.8%), basal area (89.3%) and aboveground biomass (87.6%) compared to the observed attributes. These results suggest that the EDS model can provide reasonable capability in projecting growth dynamics of uneven-aged, mixed species sclerophyll forests.