Effects of backfill on seismic behavior of rectangular tanks     

Ramazan Livaoglu  Tufan Cakir 《Ocean Engineering》2011,38(10):1161-1173

The reliability and/or stability of the lifeline structures against failure under seismic loads are of critical concern, and must be studied carefully. Therefore, the main objective of this paper is to demonstrate the commonly encountered backfill effects on the dynamic response of rectangular tanks. However, only the exterior wall of the tank which interacts with both the backfill and fluid is tackled, as each part of the structure shows considerable differences in terms of both the load bearing mechanisms and the geometrical and positional differences. Finite element analyses are employed, taking into consideration the fluid-wall-backfill interaction. The analyses are conducted to observe whether or not both backfill and wall behavior can be affected by variation of the internal friction angle. For that purpose, some comparisons are made on vertical displacements of the backfill, roof displacements, stress responses, etc., by means of internal friction angle variations of the backfill from 25° to 40°. Consequently, it is observed that the variations on maximum vertical displacements are affected considerably. In contrast, the maximum stress responses are affected partially. However, the inertial effects of the backfill show that pseudo-static approximations may be insufficient to understand the dynamic behavior of the backfill-wall-fluid system.  相似文献   

Swashed away? Storm impacts on sandy beach macrofaunal communities     

Linda Harris  Ronel Nel  David Schoeman 《Estuarine, Coastal and Shelf Science》2011,94(3):210-221

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Feeding strategies of deep-sea sub-Arctic macrofauna of the Faroe-Shetland Channel: Combining natural stable isotopes and enrichment techniques     

E. Gontikaki  D.J. MayorB.E. Narayanaswamy  U. Witte 《Deep Sea Research Part I: Oceanographic Research Papers》2011,58(2):160-172

The response of a sub-arctic, deep-sea macrofaunal community to a simulated food sedimentation event was studied by means of a stable isotope “pulse-chase” experiment. A food pulse was simulated by adding 500 mg C m⁻² of ¹³C-labelled diatoms, Chaetoceros radicans, to sediment cores retrieved from 1080 m in the Faroe-Shetland Channel. Carbon uptake by specific macrofaunal groups was quantified after 3 and 6 days of incubation. The carbon uptake of the dominant taxon (Polychaeta) was quantified at the genus-, and where possible, species-level, representing a data resolution that is rare in deep-sea tracer studies. The macrofaunal community reacted rapidly to the diatom addition, with 47% and 70% of the animals illustrating ¹³C-enrichment after 3 and 6 days, respectively. Approximately 95% of C uptake was located in the upper 2 cm due to the particularly shallow vertical distribution of the macrofaunal community and the nonexistent tracer subduction by burrowing species. Polychaetes of the families Ampharetidae and Cirratulidae were among the most heavily labelled with above background enrichment reaching 1300‰. Approximately 0.8 and 2.0 mg C m⁻² were processed by the macrofauna after 3 and 6 days, representing 0.2% and 0.4% of the added carbon, respectively. It was not possible to differentiate sub-surface deposit-feeding polychaetes from predator/scavenger- and omnivorous polychaetes using their natural ??¹⁵N signatures. However, the combination of natural abundance ??¹⁵N data and ¹³C-labelling experiments proved to be useful for elucidating trophic relations in deep-sea food webs. This study confirms that macrofauna play an active role in the short-term carbon cycling at bathyal depths even at sub-zero temperatures and highlights the need for detailed knowledge of the community structure in understanding carbon processing patterns and early diagenesis of organic matter in marine sediments.  相似文献   

迟缓爱德华氏菌OppA蛋白的免疫原性及免疫保护分析          下载免费PDF全文

王妍妍  李贵阳  李杰  肖鹏  莫照兰 《海洋科学》2011,35(5):19-23

迟缓爱德华氏茵(Edwardsiella tarda)是水产养殖动物重要的病原茵,引起鱼类爱德华氏茵病,免疫防治是针对该病的一个有效途径.OppA是迟缓爱德华氏茵的一个寡肽透过酶组分,作者开展OppA的免疫原性及免疫保护性的研究,旨在评价其作为鱼类爱德华氏菌病疫苗候选抗原的可行性.将致病性的迟缓爱德华氏菌LSE40的o...  相似文献   

母船垂荡导致ROV脐带缆参量共振的研究     

卢其进  杨和振 《海洋技术学报》2011,30(3):77-82

研究有缆遥控潜水器(Remote Operated Vehicles)的脐带缆受到轴向激励所产生的大幅横向振动,即参量共振.ROV脐带缆的参激现象发生会影响ROV的安全性.针对ROV脐带缆的结构特性,推导出其在轴向激励力下的非线性振动方程.运用希尔无穷行列式的方法分析脐带缆的参量不稳定性.以稳定性图为基准分析脐带缆在多...  相似文献   

浮基多体系统在波浪中展开的数值模拟   总被引：1，自引：1，他引：0  

江召兵  杜乃娟  陈徐均  洪娟 《海洋工程》2011,29(4):114-118

浮基多体系统在波浪中展开过程的顺序与快慢对系统的运动响应和连接处的力矩有较大影响。介绍了建立在齐次矩阵方法基础上的浮基多体系统时域运动求解,并对一具体浮基系统进行了建模和数值模拟,分析了上部机构以一定规律快速展开和慢速展开时系统的运动响应。结果表明,把齐次矩阵方法引入浮基多体系统的求解领域,其符号推导方便,运动学和动力学方程表达式变得相当简洁,而且编制程序也相对简便快捷。在相同波浪周期的情况下,多体系统的最大横摇角响应与波高正相关;在相同波高情况下,长周期的最大横摇响应要比短周期小;相对于波周期,波高对系统横摇响应的影响要大的多。  相似文献   

南海盐度对南海夏季风响应的初步分析   总被引：5，自引：0，他引：5  

李秀珍  梁卫  温之平  蔡榕硕 《热带海洋学报》2011,30(1)

为分析南海盐度对南海夏季风的响应情况,采用1967-2001年共35年的月平均海洋同化数据(SODA)等资料,利用合成等分析方法,探讨了南海上层盐度与净淡水通量、风应力、Ekman抽吸速度的关系以及不同海域盐度对南海夏季风爆发以及季风强度的响应.结果表明,随着南海夏季风建立,南海北部、东部的盐度降低,南部盐度增加.在强季风年,南海北部沿岸、东部盐度偏低,南海南部马来西亚以北海域盐度偏高;弱季风年南海盐度异常分布则为北部、东部盐度偏高,南部盐度偏低.南海上层盐度对南海夏季风爆发和季风强度的响应均与南海的净淡水通量、风应力、Ekman抽吸速度存在密切关系.  相似文献   

双壳类分子生物标志物对海水重金属的响应评述   总被引：1，自引：0，他引：1  

孟范平  高鹰  赵顺顺  付海防  肖静 《中国海洋大学学报(自然科学版)》2011,41(5):100-109

海洋双壳类动物的组织和器官对微量重金属具有高富集能力,诱导机体内的某些分子生物标志物(molecular biomarkers,MBMs)发生变化,可用于指示海水中的重金属污染水平。近10年来,许多学者在双壳类MBMs对海水重金属的响应规律方面进行了研究,其中,金属硫蛋白(MTs)、热激蛋白70(HSP70)、抗氧化防御系统等受到了较多的关注。本文在介绍这些MBMs结构和功能的基础上,重点评述了各种MBMs对海水重金属的响应特征,并提出了影响双壳类MBMs应用于海水重金属监测的因素及进一步研究的方向。  相似文献   

基于多体分析的浅水FPSO和水下软钢臂系泊系统运动特性研究     

李淑一  王树青 《中国海洋大学学报(自然科学版)》2011,41(9):95-102

基于多体动力分析方法进行FPSO和水下软钢臂系泊系统的运动特性研究。相较于非线性弹簧模拟软钢臂系泊系统或者其他近似模拟方法,多体分析方法可以充分考虑系泊系统具体结构形式及其动力项对FPSO运动性能的影响,更好的预报系统运动响应和系泊力。本文将FPSO和水下钢臂结构模拟成2个具有6自由度的独立结构,两者用系泊链组进行连接。基于三维势流理论应用汇源分布法,首先在频域内进行FPSO的水动力参数分析,进而在时域内对系统进行耦合动力分析。本文重点讨论系泊系统黏性力和二阶波浪力对系统响应的影响,计算结果发现系泊系统黏性力对系泊力有一定影响,而在浅水条件下二阶波浪力的计算对准确预报系统运动及系泊力非常重要。  相似文献   

利用数字地震波资料研究宁夏地区介质非弹性衰减和场地响应     

许英才  许文俊  李鸿庭  陈继锋 《大地测量与地球动力学》2011,31(Z1):33-37

利用宁夏及邻区的数字地震波资料,选取2009-05-2010-10月M_L2.6以上的20个台站32次地震事件的268条波形记录,用遗传算法反演了宁夏及邻区介质非弹性衰减系数和台站场地相应.反演得到:宁夏地区介质非弹性衰减Q值与频率的关系为Q(f)=337.67f0.4554.其Q值和山西及浙江地区的结果最相近,可能预...  相似文献