The Transferability of Terrestrial Water Balance Components under Uncertainty and Nonstationarity: A Case Study of the Coastal Plain Watershed in the Southeastern USA

The challenges posed by nonstationarity in predicting catchment water balance components motivated this study to test the stationary versus nonstationarity hypothesis and detect changes in the watershed response to land use land cover (LULC) alterations, and climate variability and change. The focus is on a two‐step procedure that includes model calibration of Soil and Water Assessment Tool using a sequential Bayesian uncertainty algorithm (i.e. sequential uncertainty fitting), followed by nonstationary assessment of water balance component using extreme value analysis over an Atlantic coastal plain watershed in the southeastern USA. Analysis suggests that the uncertainty of Soil and Water Assessment Tool model is statistically aligned with LULC alterations that increased the sensitivity of Manning's roughness coefficient, transmission loss and the resistance of the soil matrix to water flow. Changes in LULC along with variability in the magnitude, timing and frequency of precipitation diminished surface runoff and groundwater contribution to the river system whereas it increased evapotranspiration with a substantial decline in water storage capacity. Nonstationary assessment of water balance using extreme value analysis model further revealed a functional form of stationary behaviour (no trends) prior to LULC alteration while large amplification was detected during post‐changes. The results and findings presented in this paper confirm our hypothesis about a combined effect of climate and LULC changes on hydrological functions and that variation of these fingerprints elucidates the presence of nonstationarity in the watershed system. Copyright © 2017 John Wiley & Sons, Ltd.     

The effect of ventilation on indoor exposure to semivolatile organic compounds

A mechanistic model was developed to examine how natural ventilation influences residential indoor exposure to semivolatile organic compounds (SVOCs) via inhalation, dermal sorption, and dust ingestion. The effect of ventilation on indoor particle mass concentration and mass transfer at source/sink surfaces, and the enhancing effect of particles on mass transfer at source/sink surfaces are included. When air exchange rate increases from 0.6/h to 1.8/h_, the steady‐state SVOC (gas‐phase plus particle phase with log K_OA varying from 9 to 13) concentration in the idealized model decreases by about 60%. In contrast, for the same change in ventilation, the simulated indoor formaldehyde (representing volatile organic compounds) gas‐phase concentration decreases by about 70%. The effect of ventilation on exposure via each pathway has a relatively insignificant association with the K_OA of the SVOCs: a change of K_OA from 10⁹ to 10¹³ results in a change of only 2–30%. Sensitivity analysis identifies the deposition rate of PM_2.5 as a primary factor influencing the relationship between ventilation and exposure for SVOCs with log K_OA = 13. The relationship between ventilation rate and air speed near surfaces needs to be further substantiated.     

街道景观作为城市重要公共领域的研究—以北京CBD核心区为例

街道景观作为市政工程,追求安全和效率;同时,街道景观作为重要的公共领域,也是城市文化和生活展开的舞台。本文以北京市CBD核心区街道景观设计为例,探讨采用交通缓流措施,突出步行"优先区域"和提高街道步行区的环境品质。同时,结合城市设计和建筑设计原则,整合所有资源进行一体化设计,形成行人可以步行、交流、停坐、休闲的空间,创造多样性的街道功能。     

Evaluating the effectiveness of urban growth boundaries using human mobility and activity records

We proposed a methodology to evaluate the effectiveness of Beijing’s Urban Growth Boundaries (UGBs) using human mobility and activity records (big data). The research applied data from location check-in, transit smart card, taxi trajectory, and residential travel survey. We developed four types of measures to evaluate the effectives of UGBs in confining human activities and travel flows, to examine the conformity of urban activities with the planned population, and to measure the activity connections between UGBs. With the large proportions of intra- and inter-boundary travel flows and an overwhelming majority of check-ins inside the UGBs, the research concluded that Beijing’s UGBs were effective in containing human mobility and activity. However, the connections between UGBs, indicated by the spatial differentiation of the travel flows, were not consistent with the plan’s intention and strategy. It indicated the potential underdevelopment of the public transit serving several new cities.     

对北京市工业用水管理的建议

针对工业用水所涉及的问题提出建议，同时对用水定额和用水指标的制定，用水定额的影响因素做了较为系统的分析。认为考核的指标是产品的用水定额和企业的用水指标，但对于一些附加定额或者二级指标也要进行了解。在考核的2个指标中，用水定额应当相对固定，而用水指标则可以根据情况适当调整。     

岩石隧道二次襯砌之耐震設計考量初探

回顧二次襯砌的設計理念及現行耐震設計的考量,建立混凝士二次襯砌受地震力之力學行為模式,由本模式來解釋混凝土二次襯砌在地震力作用下的破壞模式,並由可能的破壞模式進一步建立耐震設計之基本需求。同時,由韌性的觀點分析無筋與钢筋混凝土二次襯砌設計的耐震表現,並將利用研究成果針對混凝土二次襯砌進行案例探討,最後根據土木設計極限狀態設計及破壞模式控制2項基本原則,探討二次襯砌設計理念及提出設計建議。     

应用GIS提高北京市城市河湖管理现代化水平

主要介绍地理信息系统在北京市城市河湖日常工作中的应用思路，阐述GIS在城市河湖防汛、供水、水质监测等工作中的作用。     

北京水源地的保护意义及措施初探

北京水源地保护对维持首都的可持续发展和各流域的生态平衡具有重要的现实意义和深远的历史意义，文中从生态保护，节约用水，实行全流域综合管理以及执行合理的水价体系等方面阐述了水源地保护的意义，并认为生态保护是根本，是长久之计，而节约用水，实行全流域综合调度管理以及执行合理的水价体系等则是实现水资源可持续利用和缓解水资源危机的重要对策。     

一凿井工程的施工实例

受自然条件的限制,豫东黄淮河冲积平原地区主要开采地下水资源,以一凿井工程实例,简要介绍该工程的成井工艺.