Wave impacts on structures with rectangular geometries: Part 2 decks,baffles and seawalls with impermeable or porous surfaces

This paper considers wave impacts on baffles, on baffles or decks adjacent to a vertical wall, and on porous seawalls and/or sea beds. For seawalls and vertical baffles, impacts can occur in steep waves, whilst a deck can be struck from below by a rising wave crest either in open sea or in a tank with standing waves (sloshing). A simple analytical model for the pressure impulse, P, due to a wave of idealized geometry and dynamics is developed and applied to the following geometries with impermeable surfaces:

• •horizontal wave impact onto a vertical wall with a deck at the waterline,
• •vertical wave impact under a deck in the same configuration (equivalent to vertical water impact of a horizontal plate),
• •horizontal wave impact onto a surface-piercing vertical baffle in open sea,
• •as for 3. but with the baffle in front of a wall,
• •as for 4. but with a deck extending from the vertical wall to the baffle,
• •bottom-mounted baffle in front of a wall with impact occurring on the wall.

We also consider cases that complement part 1 of this paper to include the effect on impacts on a seawall with a porous sea bed and/or sea wall with/without a berm. Finally we reconsider case 3) above but with a porous baffle.The method uses eigenfunction expansions in each of the rectangular regions that satisfy some of the impermeable or porous surface conditions, and a simplified free-surface condition. Their unknown coefficients are determined from the impact boundary condition, impermeable or porous boundary conditions and by matching the solutions, in any two neighbouring rectangles, along their common boundary. Although the fluid motion is treated rather crudely, the method yields the pressure impulse throughout the entire region. Impulses, I, and moment impulses, M, on all or parts of the structure are also presented.     

基于GIS评价活动断裂对公路的影响——以宁夏地区为例

为了查清活动断裂对公路的影响,总结了宁夏地区9条全新世活动断裂的基本特征和活动性,确定了评价和预测活动断裂对公路工程影响的指标体系,并建立了分级标准。采用优先排序法对指标进行筛选和优化,运用主成分分析法确定权重,选用多级模糊综合评判法建立了评价模型。以ARCGIS9为平台,建立了宁夏地区活动断裂空间数据库,运用矢量叠加运算实现了宁夏地区活动断裂对公路影响的现状评价,运用栅格叠加运算实现了宁夏地区海原活动断裂带对公路影响的预测评价。预测结果表明,宁夏地区对公路影响大的海原活动断裂面积为12．34km2,占全区总面积的1．0％;影响较大的为271．28km2,占总面积的21．4％;影响中等的为400．05km2,占总面积的31．6％;影响小的为585．04km2,占总面积的46．0％。     

Hydrological impact of forest-fire from paired-catchment and rainfall–runoff modelling perspectives

Abstract

This study deals with the Rimbaud catchment, a sub-catchment within the Réal Collobrier hydrological observatory in southeastern France, managed by Irstea since 1966. This observatory suffered a wildfire in 1990. Because of the dense network of streamgauges and raingauges available, this site provides a unique opportunity to test and compare two types of analysis, one based on paired catchments and the other a rainfall–runoff model, used to assess the hydrological impact of forest fire. In the present case, more than 20 years of pre-fire and post-fire data are available. We compare the ability of the two approaches to detect gradual changes at a daily time step. This case study illustrates how natural climatic variability (here a long drought which preceded the wildfire) can make the identification of hydrological changes extremely difficult.     

PM2.5 and ozone pollution-related health challenges in Japan with regards to climate change

The degradation of air quality, an environmental consequence of anthropogenic activities, poses a challenge to human health. However, the corresponding control measures incur additional costs. This study presents an analysis of the health and socioeconomic benefits of air quality control measures and climate change mitigation. Multidisciplinary modelling was used for PM_2.5 and ozone distribution to analyze the co-benefits of end-of-pipe measures and electrification as well as their period-specific impacts on human health and the economy. The results indicated that the long-term impacts of end-of-pipe technologies and electrification in Japan's residential, building, and transportation sectors could reduce premature deaths, caused by PM_2.5 and ozone pollution, by 65,500 annually from 2010 to 2050. These technologies could save a per capita work hour loss of 3.64 h and avoid an economic loss of 5.43 billion USD by 2050. This study predicted climate actions would enable western Japan to benefit from PM_2.5 control measures, whereas the entire country would benefit from ozone pollution reduction.     

互花米草化学治理对天津附近海域水质和沉积物质量的影响

互花米草作为入侵物种对潮间带滩涂和盐沼具有严重的生态危害性,化学方法治理互花米草具有简便、快速、彻底和成本低等特点,但化学药剂存在一定毒性,可能会对周边环境带来一系列不利影响,然而目前有关化学治理措施所带来的环境影响的研究较少。本文基于2017年8-11月的调查数据,研究了天津市永定河河口附近滩涂互花米草化学治理对附近海域海水水质和潮间带沉积物产生的影响,对调查海域海水水质和沉积物质量进行了评价。调查与评价结果表明,无机氮、活性磷酸盐和化学需氧量（COD）为调查海域的主要污染因子,硫化物为潮间带沉积物的主要污染因子。施药后特征污染物——草甘膦检测值高于本底值,所有站位均未检出磺酰脲类除草剂。综合来看,化学治理对附近海域海洋环境的影响较小。     

印度未来能源需求对中国获取境外能源的影响初探

印度拥有全球18%的人口,消费全球约5%的一次能源,创造了全球8%左右GDP,是全球发展最快的国家之一,探讨印度未来能源需求对中国获取境外能源的影响具有重要的战略意义。本文在分析印度社会经济发展和能源消费的基础上,利用人均能源消费"S"形模型对2030年印度一次能源需求进行了预测并探讨了其对中国获取境外能源的影响。研究认为2030年以前,印度未来能源需求不会对中国境外获取天然气和铀矿资源产生较大影响。而由于中印两国石油进口量较大且与所有的增长都存在叠加,将影响全球石油的供需格局。同时鉴于两国石油进口来源地具有高度重叠性,印度未来能源需求的增加,将对中国境外获取石油资源产生重要的影响。     

六盘山盆地黄土塬区地震数据采集技术

宁夏南部六盘山盆地属于典型黄土塬地貌的沉积盆地,该区表层沉积了巨厚黄土层,深层不同构造单元差异大,在地震数据采集上需克服地表和地下的双重影响。分析了该区地质条件以及勘探难点,结合实际资料并应用新技术和新方法,总结出一套针对该区的地震数据采集技术,可以指导该区后期地震勘探工作。     

海洋平台基于隔振锥体装置的减振效应研究

针对导管架式海洋平台结构型式与特点,利用冲击隔振理论,将冰锥体与隔振技术结合起来,提出一种能有效降低冰荷载激励的"两级柔性隔振锥体"设计方案。建立了两极隔振锥体简化计算模型,确定了系统振动传递系数参数之间的关系。通过建立海洋平台有限元模型,采用有限元程序,进行了模拟冰荷载激励下的振动响应分析,并对安装隔振装置的小比例模型结构进行了冲击荷载下的减振试验。结果表明采用"两级柔性隔振锥体"能有效降低传递给海洋平台的冰力极值,减小海洋平台冰激励的响应。     

ZYXC-244机械式旋冲螺杆钻具的研制与应用

针对现有常规螺杆钻具在研磨性强、可钻性差的难钻地层中存在破岩能量不足、机械钻速低、钻头消耗量大的问题,引入旋冲钻井破岩理念及轴向机械冲击破岩功能,研制了集合旁通阀总成、动力总成、传动总成和冲击总成于一体的ZYXC-244机械式旋冲螺杆（新型螺杆）,并创新设计了防掉功能。通过对新型螺杆主要性能参数计算模型的分析,获取了其主要性能参数的特征变化曲线。新型螺杆先后在足203H1-3井和大湾4011-2井的须家河组等地层进行了现场应用,应用效果表明,新型螺杆进尺分别为685.00 m和72.53 m时与常规螺杆相比,机械钻速分别提高了38.2%和31.5%,节省了起下钻2次和2只钻头消耗,为难钻地层的提速提效提供了有效的技术手段。     

舟山海域外来物种地中海贻贝的自然分布现状及生态影响

以筛选的2个可鉴别的地中海贻贝（Mytilus galloprovincialis）、厚壳贻贝（M.coruscus）及其杂交后代的PCR标记（扩增核基因Glu-5’特异片段PCR标记Me14/Me17和延伸因子1α第一个内含子区段PCR标记引物EFbisF/EFbisR）,对舟山海域3个贻贝主产区（马鞍列岛海域、浪岗山列岛海域、中街山列岛海域）采集的贻贝样本的种类进行鉴别.研究结果显示：100个马鞍列岛海域贻贝个体和30个中街山列岛海域贻贝个体均为厚壳贻贝;而54个浪岗山列岛海域贻贝样本中,16个个体（29.6%）为厚壳贻贝,38个个体（70.4%）为地中海贻贝;3个群体中均未检测到2种贻贝的杂交个体.因此,推测舟山海域地中海贻贝自然分布仅局限于局部海区,但在适宜的海区地中海贻贝可取代厚壳贻贝成为贻贝床的优势物种,舟山海域贻贝床的动态变化值得进一步关注;贻贝样本中没有检测到地中海贻贝与厚壳贻贝的杂交个体,表明调查海域可能没有杂交贻贝分布或数量极少,地中海贻贝通过杂交、基因渐渗污染厚壳贻贝基因组的风险较小.