School building condition,school attendance,and academic achievement in New York City public schools: A mediation model

Little is known about how the condition of school facilities affects academic outcomes. This study examines the role of school attendance as a mediator in the relationship between facilities in disrepair and student grades in city and state tests. Data on building condition and results from English Language Arts (ELA) and Mathematics (Math) standardized tests were analyzed using a sample of 95 elementary schools in New York City. Variables relevant to academic achievement such as ethnicity, socioeconomic status, teacher quality, and school size were used as covariates. In run-down school facilities students attended less days on average and therefore had lower grades in ELA and Math standardized tests. Attendance was found to be a full mediator for grades in ELA and a partial mediator for grades in Math. This study provides empirical evidence of the effects of building quality on academic outcomes and considers the social justice issues related to this phenomenon.     

Life-cycle cost-benefit analysis of extensive vegetated roof systems

The built environment has been a significant cause of environmental degradation in the previously undeveloped landscape. As public and private interest in restoring the environmental integrity of urban areas continues to increase, new construction practices are being developed that explicitly value beneficial environmental characteristics. The use of vegetation on a rooftop--commonly called a green roof--as an alternative to traditional roofing materials is an increasingly utilized example of such practices. The vegetation and growing media perform a number of functions that improve environmental performance, including: absorption of rainfall, reduction of roof temperatures, improvement in ambient air quality, and provision of urban habitat. A better accounting of the green roof's total costs and benefits to society and to the private sector will aid in the design of policy instruments and educational materials that affect individual decisions about green roof construction. This study uses data collected from an experimental green roof plot to develop a benefit cost analysis (BCA) for the life cycle of extensive (thin layer) green roof systems in an urban watershed. The results from this analysis are compared with a traditional roofing scenario. The net present value (NPV) of this type of green roof currently ranges from 10% to 14% more expensive than its conventional counterpart. A reduction of 20% in green roof construction cost would make the social NPV of the practice less than traditional roof NPV. Considering the positive social benefits and relatively novel nature of the practice, incentives encouraging the use of this practice in highly urbanized watersheds are strongly recommended.     

Comparison of membrane fouling during short-term filtration of aerobic granular sludge and activated sludge

Aerobic granular sludge was cultivated adopting internal-circulate sequencing batch airlift reactor.The contradistinctive experiment about short-term membrane fouling between aerobic granular sludge system and activated sludge system were investigated.The membrane foulants was also characterized by Fourier transform infrared(FTIR)spectroscopy technique.The results showed that the aerobic granular sludge had excellent denitrification ability;the removal efficiency of TN could reach 90%.The aerobic granular sludge could alleviate membrane fouling effectively.The steady membrane flux of aerobic granular sludge was twice as much as that of activated sludge system.In addition,it was found that the aerobic granular sludge could result in severe membrane pore-blocking, however,the activated sludge could cause severe cake fouling.The major components of the foulants were identified as comprising of proteins and polysaccharide materials.     

基于STPA和模糊BN的装配式建筑吊装施工安全风险分析

为有效评估装配式建筑吊装施工中的安全风险状态,识别关键风险因素,运用系统理论过程分析方法(STPA)构建吊装施工过程中的控制反馈结构,识别导致危险的不安全控制行为,确定不安全控制行为的致因因素;基于风险因素间的关联关系构建贝叶斯网络(BN)模型,推理计算装配式建筑吊装施工安全风险状态概率,并结合反向诊断推理分析影响安全事故的风险因素;通过敏感性分析,识别装配式建筑吊装施工安全中的关键风险因素。结果表明：装配式建筑吊装施工安全风险处于低风险状态;起重机械超负荷运行、现场安全管理不到位和吊索吊具存在缺陷等因素是影响装配式建筑吊装施工安全风险的关键风险因素。     

塔机起重作业夜间照明工效的BIM辅助优化研究

为提升塔式起重机施工作业的夜间照明工效水平,采用数学模型和BIM技术相结合的方法,以灯源的光通量及入射角为光学驱动参数,模拟眩光值、照度及其均匀度等光学变量,建立照明工效的光度学BIM辅助优化模型,优化起重作业照明灯源光学参数。研究结果表明：对塔式起重机施工作业区照明灯源光学参数进行组合优化后,夜间起重作业面照度及其均匀度显著提升,眩光值满足起重作业视觉环境条件。研究结果可为塔式起重机夜间起重作业照明方案设计提供科学依据。     

新形势下再生原料进口制度改革初探

禁止进口固体废物是我国打击“洋垃圾”入境的重要举措。固体废物与再生原料界限模糊导致政策实施过程中存在执行难度,固体废物属性鉴别作为技术手段难以完全应对,进口制度需要进一步改革。通过对进口固体废物及再生原料管理政策分析,再结合固体废物属性鉴别过程中的实际难题,梳理出制度体系不完善、标准规范不健全、技术水平欠缺三方面的问题。为防止固体废物冒充再生原料入境,提出构建完善新型制度体系、建立健全标准规范、加强能力建设等具体举措。     

某教学楼火灾中人员安全疏散时间的预测

文章分析了大型建筑物内人员疏散的特点,结合某幢教学楼的设定火灾场景人员的安全疏散,对该建筑物火灾中人员疏散的设计方案做出了初步评价,得出了一种在人流密度较大的建筑物内,火灾中人员疏散时间的计算方法和疏散过程中瓶颈现象的处理方法,并提出采用距离控制疏散过程和瓶颈控制疏散过程来分析和计算建筑物的人员疏散。     

浅析室内空气污染

室内空气污染会引发呼吸道疾病,并对神经系统、免疫系统和肝脏都有毒害作用,还是多种流行病传播的媒介,已成为多种疾病发生率提高的主要致病因素,严重影响了人们正常的工作和生活.本文从消费、城市规划和政策法规的角度,分析了产生室内空气污染的主要原因;提出了可以从装修方案设计和建材选择、先进净化技术的采用、选择合理入住时间、健全室内空气质量监测指标、发挥政府调控作用、合理规划城市功能六个方面采取措施,进行室内空气污染的防治.为实现城市居民生活的安全、舒适、健康、美观提供了可参照的科学方法.     

利用新型稀土铈铁复合吸附剂去除水体腐殖质的研究

研究了稀土铈铁复合材料(CFA)对水体中黄腐酸(FA)的去除效能和作用机制.结果表明:CFA在平衡pH3.0～6.5的范围内对FA的去除效果较好,吸附速度快,120min即达到平衡.水体中FA与砷酸根在CFA上有很强的竞争作用,当FA加入量为5mg/L～10mg/L时,砷的饱和吸附量Q_o即丧失40%～50%,表明两者作用于材料相同的活性位点.吸附前后的红外谱图(FTIR)揭示了CFA表面羟基在FA去除中起着重要作用.通过Zeta电位的测定得出材料的等电点为5.6,因而pH偏酸性的条件有利于FA的去除.     

酸沉降对材料破坏的损伤函数的研究

估算酸沉降破坏材料造成的经济损失，必须首先建立材料损伤函数式．为此本研究在自行设计和建造的室内模拟环境材料暴露试验装置上进行了变动两种主要因素的材料暴露试验；结合室内和现场材料暴露试验的结果建立了５种有代表性材料的二元损伤函数式．