A Data‐Driven Approach to Assessing Supply Inadequacy Risks Due to Climate‐Induced Shifts in Electricity Demand

The U.S. electric power system is increasingly vulnerable to the adverse impacts of extreme climate events. Supply inadequacy risk can result from climate‐induced shifts in electricity demand and/or damaged physical assets due to hydro‐meteorological hazards and climate change. In this article, we focus on the risks associated with the unanticipated climate‐induced demand shifts and propose a data‐driven approach to identify risk factors that render the electricity sector vulnerable in the face of future climate variability and change. More specifically, we have leveraged advanced supervised learning theory to identify the key predictors of climate‐sensitive demand in the residential, commercial, and industrial sectors. Our analysis indicates that variations in mean dew point temperature is the common major risk factor across all the three sectors. We have also conducted a statistical sensitivity analysis to assess the variability in the projected demand as a function of the key climate risk factor. We then propose the use of scenario‐based heat maps as a tool to communicate the inadequacy risks to stakeholders and decisionmakers. While we use the state of Ohio as a case study, our proposed approach is equally applicable to all other states.     

Risk Mapping of Groundwater‐Drawdown‐Induced Land Subsidence in Heterogeneous Soils on Large Areas

Groundwater leakage into subsurface constructions can cause reduction of pore pressure and subsidence in clay deposits, even at large distances from the location of the construction. The potential cost of damage is substantial, particularly in urban areas. The large‐scale process also implies heterogeneous soil conditions that cannot be described in complete detail, which causes a need for estimating uncertainty of subsidence with probabilistic methods. In this study, the risk for subsidence is estimated by coupling two probabilistic models, a geostatistics‐based soil stratification model with a subsidence model. Statistical analyses of stratification and soil properties are inputs into the models. The results include spatially explicit probabilistic estimates of subsidence magnitude and sensitivities of included model parameters. From these, areas with significant risk for subsidence are distinguished from low‐risk areas. The efficiency and usefulness of this modeling approach as a tool for communication to stakeholders, decision support for prioritization of risk‐reducing measures, and identification of the need for further investigations and monitoring are demonstrated with a case study of a planned tunnel in Stockholm.     

磷酸酯/Fe3+ 型油基冻胶压裂液性能研究

针对磷酸酯/Al3+ 交联的油基压裂液交联速度慢，交联剂溶解性慢、稳定性差和价格高等缺点，首次对磷酸酯/Fe3+ 交联的油基压裂液体系进行了研究。通过对铁交联剂体系的优化，筛选一种磷酸酯/Fe3+ 交联的新型交联剂体系，并对磷酸酯/Fe3+ 油基冻胶压裂液性能进行了评价。结果表明：采用30%Fe2(SO4)3+15% 二乙醇胺+55% 水制备的新型交联剂体系，直接与磷酸酯混合即可形成油基冻胶，其性能不受放置时间的影响，交联速度快，成胶性能好，10 min 就可达到最大黏度；压裂液的抗温抗剪切性能高，与常规铝交联剂体系比较，压裂液成胶速度提高了20 倍，压裂液的抗温能力由原来100 ℃提高到135 ℃，并且压裂液的破胶性和滤失性等性能均能达到压裂施工的要求。     

Differences in meconium stained amniotic fluid in an Australian population: A retrospective study

Background

Meconium stained amniotic fluid commonly occurs postdates (?>40 weeks gestation) indicating fetal maturity. Previous literature indicates that different ethnicities mature at different rates.

重载铁路圆柱形桥墩横向振动试验研究

随着我国既有铁路扩能运输的实施,运营列车的轴重以及载运量逐步增加给圆柱形桥墩带来了越来越严重影响,如墩顶横向振幅过大、冲击振动加剧等,严重影响了铁路桥梁的安全运营。以朔黄铁路圆柱形桥墩为研究对象,理论结合试验分析其加固前后在列车荷载增大的情况下桥墩的横向动力特性,研究不同运营列车作用下桥墩横向振动的规律,评价分析该圆柱形桥墩加固效果,为重载铁路圆柱形桥墩的加固研究和维护管理提供科学依据。     

基于扭转振动的多步态移动装置的运动学建模

为了实现移动机器人多步态稳定运动,提出一种新型的利用自身的结构特性来设计移动装置的方法。通过对其 倒立的U型结构的设计,再分别对该移动装置滑、走、跑和跳4个步态进行运动学建模,最后利用ADAMS仿真实现了该 移动装置稳定的多步态的运动。然后根据仿真结果给出了各运动相在每个步态周期中的足地接触距离以及横梁质心位 移的变化情况,最后讨论了影响该移动装置多步态运动的因素,如机体与两腿的长度之比r、共振频率和电机转速等。 结果表明该移动装置实现了多步态的运动,对未来研究多步态移动机器人提供了理论基础。     

水平井分段多簇压裂缝间干扰研究

水平井分段多簇压裂在现场得到了广泛运用，其压裂过程中普遍存在缝间干扰现象。缝间干扰有助于形成复 杂裂缝网络以提高储层导流能力，但是也会导致起裂困难，甚至形成砂堵。因此有必要对分段多簇压裂的缝间干扰问 题进行研究。对此，基于弹性力学建立了分析多簇裂缝诱导应力的数学模型，从起裂压力、裂缝宽度、簇间距等多方面 研究了缝间干扰对水平井分段多簇压裂施工的影响。模拟结果显示，诱导应力会导致起裂压力升高、裂缝变窄，严重 时将造成压裂施工失败。通过进行分析，给出了起裂过程及延伸过程中缝间干扰的影响关系。分析认为，利用缝间干 扰提高改造体积时应当控制簇间距防止对压裂施工造成负面影响。研究结论对优化水平井分段多簇压裂设计具有指 导意义。     

1906-1908年的郑孝胥与预备立宪公会

考虑到我国未来年度的OD分布预测中的路网构成变化、区域经济布局变动、区域经济增长速度差异等一些具有时变性和特殊性因素，采用在“四阶段法”运量预测基础上改进而成的“三阶段法”进行高速铁路短期客运量预测。首先采用组合预测模型进行趋势运量预测，然后采用多元LOGIT模型进行方式分担，最后采用弹性系数诱增模型进行诱增运量预测。以京沪高铁为例，采用“三阶段法”预测了2014年和2015年京沪高铁本线及跨线单向客流量。     

可拆装式湿法剪切粉碎设备结构设计与转子系统动态分析

为解决工业化生产中大量韧性湿物料粉碎难度大、粉碎部件磨损严重的难题,对大功率湿法剪切粉碎设备的关键部件进行结构设计与优化,将定转子优化为可装拆式结构。通过工程软件ANSYS对转子进行变形分析与模态分析,分析其高速转子系统的振动特征,为关键部件的结构设计与优化提供理论依据,为整机的动态稳定性分析奠定基础。