Evaluating crude oil chemical dispersion efficacy in a flow-through wave tank under regular non-breaking wave and breaking wave conditions

Testing dispersant effectiveness under conditions similar to that of the open environment is required for improvements in operational procedures and the formulation of regulatory guidelines. To this end, a novel wave tank facility was fabricated to study the dispersion of crude oil under regular non-breaking and irregular breaking wave conditions. This wave tank facility was designed for operation in a flow-through mode to simulate both wave- and current-driven hydrodynamic conditions. We report here an evaluation of the effectiveness of chemical dispersants (Corexit^® EC9500A and SPC 1000^™) on two crude oils (Medium South American [MESA] and Alaska North Slope [ANS]) under two different wave conditions (regular non-breaking and plunging breaking waves) in this wave tank. The dispersant effectiveness was assessed by measuring the water column oil concentration and dispersed oil droplet size distribution. In the absence of dispersants, nearly 8-19% of the test crude oils were dispersed and diluted under regular wave and breaking wave conditions. In the presence of dispersants, about 21-36% of the crude oils were dispersed and diluted under regular waves, and 42-62% under breaking waves. Consistently, physical dispersion under regular waves produced large oil droplets (volumetric mean diameter or VMD ? 300 μm), whereas chemical dispersion under breaking waves created small droplets (VMD ? 50 μm). The data can provide useful information for developing better operational guidelines for dispersant use and improved predictive models on dispersant effectiveness in the field.     

华东地区地震条带预报效能评估

对华东地区1970年以来的地震条带进行了预报效能评估。 结果表明: M_L≥3.0地震条带的报准率为0.33, 虚报率为0.67, 漏报率为0.71, R值为0.20; M_L≥3.5地震条带的报准率为0.40, 虚报率为0.60, 漏报率为0.81, R值为0.12; M_L≥4.0地震条带的报准率为0.71, 虚报率为0.29, 漏报率为0.76, R值为0.18; 各震级档条带的R值等于或高于具有97.5%置信水平的R₀值, 具有一定的预报能力。 主震一般发生在条带结束后1年时间内, 多数发生在条带内部和边缘, 条带以北东向或北北东向居多; 对于条带的平均持续时间, 震级下限越大的条带平均持续时间越长; 多数条带分布在江苏及附近海域和赣北及邻区。     

Post-fire soil erosion mitigation at the scale of swales using forest logging residues at a reduced application rate

Mulching with forest residues has proved to be highly effective in reducing post-fire soil losses at the plot scale. However, its effectiveness has not been quantified at the application rates that are typically used in operational post-fire land management (2–3 Mg ha^-1 using straw), as well as at scales larger than 100 m². The present study compared post-fire erosion rates for six convergent hillslopes or swales of 500 to 800 m², three of which were left untreated while the other three were mulched immediately after the fire with shredded eucalypt bark at a rate of 2.4 Mg ha^-1. Erosion rates were monitored at irregular intervals during the first three post-fire years, whilst ground cover was assessed yearly. Selected topsoil properties (0–2 cm) such as organic matter content and aggregate stability were determined at a single occasion – two years after the wildfire, for three micro-environments separately: bare soil, and under mulch/litter and vegetation. Soil losses on the untreated swales decreased with post-fire year from 2.2 to 0.4 and 0.11 Mg ha^-1 yr^-1 (respectively for the first, second and third post-fire years), while the mulched swales produced 84%, 77% and 38% less soil losses than the untreated swales. Soil losses also depended on slope aspect, with the north-facing swales producing less erosion than the west-facing ones. This could be linked to their significant differences in bare soil, vegetation and stone cover, or a combination thereof. The type of micro-environment also played a significant role in topsoil properties (stone content, bulk density, resistance to penetration/shear stress, porosity and organic matter content). The present results add to the increasing evidence that forest residues should be duly considered for operational post-fire land management. Forest residues were highly effective in reducing erosion from swales at application rates as low as the typical 2 Mg ha^-1 of post-fire straw mulch. © 2019 John Wiley & Sons, Ltd. © 2019 John Wiley & Sons, Ltd.     

华东地区地震空区预报效能评估

对华东地区1970年以来的地震空区进行了预报效能评估。 结果表明: M_L≥3.0地震空区的报准率为0.45, 虚报率为0.55, 漏报率为0.57, R值为0.26; M_L≥3.5地震空区的报准率为0.31, 虚报率为0.69, 漏报率为0.75, R值为0.08; M_L≥4.0地震空区无对应的M_S5.5以上地震。 M_L≥3.0地震空区的R值高于具有97.5%置信水平的R₀值, 具有一定的预报能力, M_L≥3.5和M_L≥4.0地震空区不具有预报能力。 主震一般发生在空区内部边缘, 震前空区一般不会被打破; 空区的持续时间、 空区尺度、 震级下限与主震震级无明显线性关系; 空区主要分布在江苏、 山东及附近海域。     

中国精准扶贫驻村帮扶工作成效及其影响因素

基于全国6378个村的驻村帮扶数据样本,本研究分析了精准扶贫工作中驻村帮扶措施的实施与进展状况,并用计量方法识别了影响驻村帮扶成效的主要因素,测度了帮扶工作的减贫效应。驻村帮扶队伍主要由县级单位派出的男性干部组成,平均年龄为42岁且学历以大专大学为主;驻村干部采取的帮扶措施保持了因村施策原则,具体包括“输血式”与“造血式”帮扶;帮扶项目的实施和成效具有明显的地域特征,总体上西部优于中部;驻村帮扶成效受到多重因素影响,干部的年龄、学历和派出单位等个人特征会影响减贫人口的数量,驻村工作队采取的扶贫措施主要会影响教育卫生等基础设施的改善。研究结果将有助于为顺利推进中国精准扶贫和乡村振兴有效衔接提供理论依据和决策支持。     

中国能源行业碳排放强度下降过程中的省际减排成效评价

采用矫正系数衡量各省份的减排有效性,根据各省份能源行业碳排放强度及产值份额构建自上而下的全国能源行业碳排强度恒等式,运用LMDI-Ⅰ分解方法获取各省份、各省份能源行业碳排放强度及产值份额对全国能源行业碳排放强度下降的贡献率,并遵循“减排有效性-碳排放强度贡献-省份综合贡献-减排有效性与省份综合贡献关系”的思路对中国能源行业碳排放强度下降过程中各省份的减排成效进行评价。结果显示：① 中国能源行业碳排放强度呈逐年下降趋势,2016年能源行业碳排放强度较2005年下降45%。② 超过一半的省份为减排有效区且数量呈增加趋势,而减排未达标的省份多数为经济欠发达地区,各省份间的减排路径存在显著差异。③ 多数省份能源行业碳排放强度的贡献率呈上升趋势,省份差异逐渐缩小。④ 省份减排综合贡献的进位赶超势头强劲,绝大多数省份对全国能源行业碳排放强度的下降作出了贡献,且多个省份的综合贡献等级呈正向发展,东部地区是主要的降排贡献区。⑤ 减排成效良好省份数量最多,中等区多散布于东部沿海地区及少数内陆地区,欠佳区在西部地区空间格局保持相对稳定。未来各省份不仅要根据自身的减排成效特征因地制宜的选择低碳发展道路,还应与全国碳排放强度的下降形成良性互动。     

“中国高分”科技重大专项在对地观测发展历程中的阶段研究

系统梳理1998年民用航天管理机构调整,特别是2005年天地一体化结构调整实施以及国家科技重大专项高分辨率对地观测系统(下称高分专项)从2007年开始论证到实施至今10余年发展历程,揭示行业发展基本规律,首次将中国民用遥感行业发展划分为4个阶段,阐述了每个阶段主要特征、面临的问题以及创新管理实践;首次将高分专项十年历程明确为一个发展阶段,提出本行业未来发展要在高分专项阶段成果基础上,推动遥感行业继"由试验应用型向业务服务型转变"成功后,向"体系效能型"转变,再次引领和推动中国对地观测新体系建设。     

长江三角洲城市合作模式及其理论框架分析

城市合作是长江三角洲城市与区域发展中的新现象, 并且已经成为政府和学术界关注 的焦点问题。选择长江三角洲的苏锡常都市圈规划、长江三角洲城市经济协调会和江阴经济 开发区靖江园区三个典型的城市合作案例, 从伙伴关系的理论视角, 进行城市合作的实证研究, 分别探讨了科层的城市合作、自发的城市合作和混合式的城市合作三种类型伙伴关系的制度安排。基于长三角的经验, 该研究在区域尺度上对伙伴关系理论的应用进行了拓展。研究的焦点在于三种模式城市合作的有效性(绩效)。通过对伙伴关系形成过程和利益相关者互 动的追踪, 研究认为合作是否有效取决于合作的机制、合作的过程、合作的性质和领域、伙伴的选择和伙伴关系形成中利益相关者的作用。     

大气电场异常判别及预报效能的统计检验

依据郝建国等提出的异常判别规则对大气电场的原始观测资料重新进行了异常判别和分组, 并依据朱成熹等提出的效率值法,分别对监测到的异常及实际上报的异常与地震预报的相关进行了统计检验及评分,信度在 15% 以下,该方法通过了假设检验。 结果表明,这一方法用于地震预报是有统计依据的。     

地面核磁共振感应系统(NUMIS)及其在找水中的应用

地面核磁共振找水技术是一种新的地球物理勘探技术,具有直接找水的特点.本文简述了该方法的原理、仪器及工作过程,并给出了两个应用实例来说明该方法的应用效果.