Load characteristics of steel and concrete tubular members under jet fire: An experimental and numerical study     

Bong Ju Kim 《Ocean Engineering》2010,37(13):1159-1168

The aim of this study was to evaluate the load characteristics of steel and concrete tubular members under jet fire, with the motivation to investigate the jet fire load characteristics in FPSO topsides. This paper is part of Phase II of the joint industry project on explosion and fire engineering of FPSOs (EFEF JIP) ( [Paik and Czujko, 2009] and [Paik, 2010]). To obtain reliable load values, jet fire tests were carried out in parallel with a numerical study. Computational fluid dynamics (CFD) simulation was used to set up an adiabatic wall boundary condition for the jet fire to model the heat transfer mechanism. A concrete tubular member was tested under the assumption that there is no conduction effect from jet fire. A steel tubular member was tested and considered to transfer heat through conduction, convection, and radiation. The temperature distribution, or heat load, was analyzed at specific locations on each type of member. ANSYS CFX, (2008) and KFX, 2007 codes were used to obtain similar fire action in the numerical and experimental methods. The results of this study will provide a useful database to determine design values related to jet fire.  相似文献   

经济全球化变革下的世界经济地理与中国角色   总被引：1，自引：0，他引：1  

朱晟君  杨博飞  刘逸 《地理学报》2022,77(2):315-330

经济全球化浪潮下的世界经济地理格局和中国角色演变一直以来都是学术界关注的热点问题,然而当前学界偏重从国家经济模式和国际贸易角度来解释这种格局的变化,而较为缺乏基于生产组织视角的经济地理解释。因此,本文从经济地理视角出发,解析经济全球化浪潮下世界经济地理格局变动与中国角色的演变。本文揭示了在三次全球化浪潮的冲击下,世界经济地理格局从“核心—边缘”到“链式重构”再到“网络不均衡”的演变过程,以及经济全球化的驱动力如何从“贸易全球化”转变为“生产全球化”,继而朝“多元全球化”演进。本文还论述了中国如何通过战略耦合模式的动态调整实现从经济全球化的参与者到变革者的转变。本文认为这种角色转变,改变了西方发达经济体对后发经济体的预设发展路径,以及经典的产业梯度转移理论所预测的空间秩序,为全球化格局的变动带来新的重构动力与可能。最后,本文结合此次新型冠状病毒肺炎疫情全球爆发带来的影响对未来经济全球化发展存在的可能路径进行分析,并从经济地理学视角为中国未来经济全球化发展道路选择提供了参考建议。  相似文献   

DLM-FvCB模型光合能力关键参数季节性参数化方案及模拟效果评估     

林晓凤  陈报章 《地理科学》2022,42(7):1260-1271

选取包含9种植被功能型的15个通量塔观测数据（60站点年）,采用控制变量法,分别在月尺度和年尺度上对25℃时最大羧化速率（V_cmax25）进行优化,并利用未参与参数反演的站点年数据集定量评估这2种参数化方案的模拟效果。研究发现：① 在参数的季节变异方面：9种植被功能型的V_cmax25均呈现明显的季节性波动。V_cmax25的波动幅度为：冬季>秋季>春季>夏季,不同植被类型季节变化幅度相差不大,而寒带植被V_cmax25季节变化幅度接近温带植被的2倍;② 对生态系统初级生产力（GPP）估算的影响方面：V_cmax25季节性参数化方案显著提高了GPP的模拟能力和模拟精度,其中森林和灌木冬季提升最显著（R²提高了35.7%,RMSE降低了23.24%）,春秋季次之,夏季最小。然而,对于C₃草地,DLM无论采取V_cmax25季节性参数化方案还是年尺度参数化方案,均为系统低估GPP。  相似文献   

粤港澳大湾区战略耦合模式差异与区域协同     

纪捷韩  刘逸  梅慕容  朱晓玲 《热带地理》2022,42(2):171-182

基于全球生产网络的理论框架,利用战略耦合,分析大湾区各城市的战略耦合模式发展及其在全球生产网络中地位与分工的差异,以深入认识粤港澳大湾区的协同发展。研究发现：1）粤港澳三地的战略耦合模式和演变过程均存在本质差异,从属于不同的全球生产网络。香港在发展本土制造业及后来的“前店后厂”的过程中,经历了2次依附耦合到解耦的过程,在金融业上形成互惠耦合模式;而澳门在制造业上经历了2次从依附耦合到解耦的过程,在博彩业上形成了吸收耦合模式。2）珠三角各个城市战略耦合模式也存在显著差异,各城市通过不同的主导产业嵌入到不同的全球生产网络之中。3）在上述2个尺度的战略耦合差异的影响下,大湾区的区域经济没有逐步走向协同,而是出现了起伏的发展过程：各个城市早期由于耦合模式不同而协同较弱,中期由于战略耦合嵌入相同的GPN中而走向协同,后期由于解耦的出现而协同趋势衰减。文章的核心论点认为战略耦合的模式差异,导致各个城市嵌入到经济周期、生产系统、技术结构存在显著差异不同的全球生产网络之中,因此难以实现区域整体协同。  相似文献   

甘谷驿油田采油厂延长组长6油层组储层裂缝研究   总被引：1，自引：0，他引：1  

李莹  付国民 《陕西地质》2010,28(1):62-66

通过露头、岩芯裂缝描述及应用古地磁裂缝检测方法,长6储层裂缝主要以EW为主,次为SN向;在最大主应力方向为NE80°的应力场背景下,外力诱使东西向裂缝优先开启和连通,油井受效明显,含水上升快且易产生水淹,近南北向裂缝处于挤压闭合状况,裂缝孤立、连通性差,油井见效缓慢。  相似文献   

Life history, growth and production of Theodoxus fluviatilis in Lake Esrom, Denmark     

Jørn Kirkegaard 《Limnologica》2006,36(1):26-41

A population of Theodoxus fluviatilis L in the littoral zone of Lake Esrom was investigated from November 1977 to February 1979. The population was sampled every month in the winter period and twice during the rest of the year. Biomass was estimated as ash-free dry weight (AFDW) of the organic matter both of the soft parts of the animal and the shell itself. The relation between AFDW (c) and shell length (l) was log c=2.9509×log (l)−1.7120. The population comprised more than 1 year-class, which could be separated by shell length, by a narrow band on the shells and the growth of algae on the shell. The life cycle lasted years. The oldest animals had a shell length of 7.0-7.5 mm. A few individuals who were estimated to be years had a shell length up to 8.6 mm. Population density varied between 575 and 2115 individuals m⁻² on the stony substratum. The average was 1160 individuals m⁻². Mortality was low during the summer period. In winter many animals died due to the effect of ice and stormy weather on the stony substratum. Growth of the animals was estimated from the shell length. Maximum growth was observed from May to August with no growth during the winter. Egg capsules were found on the stones all year round. New capsules were found from late May to the middle of November. Most freshly laid capsules were observed in May-June and August-September. Capsules from the late summer hatched in spring and capsules laid in the spring hatched in August-September. The average annual net production for the whole population was estimated by three methods. The Allen curve method gave 1.895 AFDW m⁻², the growth-increment method gave 1.784 mg AFDW m⁻² and the Hynes method 2.284 mg AFDW m⁻². Corresponding estimated P/B ratios were 1.29, 1.30 and 1.57. Annual net-production of the four investigated year-classes was 16 mg AFDW m⁻² year⁻¹ for 1975, 224 mg AFDW m⁻² year⁻¹ for 1976, 1.258 mg AFDW m⁻² year⁻¹ for 1977 and 287 mg AFDW m⁻² year⁻¹ for 1978. P/B ratios for the three oldest year-classes were, respectively, 0.32, 0.50 and 1.67. A comparison with other investigations on gastropod life cycles, reproduction and P/B ratios is made and differences discussed. Variations are correlated to temperature, and food quality and quantity.  相似文献   

科技成果转化为现实生产力的思考     

吴学伟  张宝利 《地理信息世界》2000,(1)

文章从科技成果转化的重要性出发，分析了当前在测绘科技成果转化中存在的问题，提出一些解决这些问题的看法与建议。  相似文献   

Alaska North Slope regional gas hydrate production modeling forecasts   总被引：1，自引：0，他引：1  

Scott J. Wilson  Robert B. HunterTimothy S. Collett  Steve HancockRay Boswell  Brian J. Anderson 《Marine and Petroleum Geology》2011,28(2):460-477

A series of gas hydrate development scenarios were created to assess the range of outcomes predicted for the possible development of the “Eileen” gas hydrate accumulation, North Slope, Alaska. Production forecasts for the “reference case” were built using the 2002 Mallik production tests, mechanistic simulation, and geologic studies conducted by the US Geological Survey. Three additional scenarios were considered: A “downside-scenario” which fails to identify viable production, an “upside-scenario” describes results that are better than expected. To capture the full range of possible outcomes and balance the downside case, an “extreme upside scenario” assumes each well is exceptionally productive.Starting with a representative type-well simulation forecasts, field development timing is applied and the sum of individual well forecasts creating the field-wide production forecast. This technique is commonly used to schedule large-scale resource plays where drilling schedules are complex and production forecasts must account for many changing parameters. The complementary forecasts of rig count, capital investment, and cash flow can be used in a pre-appraisal assessment of potential commercial viability.Since no significant gas sales are currently possible on the North Slope of Alaska, typical parameters were used to create downside, reference, and upside case forecasts that predict from 0 to 71 BM³ (2.5 tcf) of gas may be produced in 20 years and nearly 283 BM³ (10 tcf) ultimate recovery after 100 years.Outlining a range of possible outcomes enables decision makers to visualize the pace and milestones that will be required to evaluate gas hydrate resource development in the Eileen accumulation. Critical values of peak production rate, time to meaningful production volumes, and investments required to rule out a downside case are provided. Upside cases identify potential if both depressurization and thermal stimulation yield positive results. An “extreme upside” case captures the full potential of unconstrained development with widely spaced wells. The results of this study indicate that recoverable gas hydrate resources may exist in the Eileen accumulation and that it represents a good opportunity for continued research.  相似文献   

电子地图工程化的研究与实践   总被引：4，自引：1，他引：3  

王大新  王长江 《地球信息科学学报》2000,2(4):80-86

电子地图是一个动态发展的概念 ,其工程系统化是实现产业化的基础和前提。本文以工程系统化的观点讨论了电子地图开发生产的工艺流程、生产管理体系及质量保证体系等内容。并指出电子地图工程系统化中应注意的几个问题.  相似文献   

Population dynamics of mayflies in a constant temperature spring stream in West Carpathians     

Kvetoslava Bottová  Tomáš Derka  Marek Svitok 《Limnologica》2013,43(6):469-474

We examined the life history and secondary production of four Ephemeroptera species (Baetis alpinus Pictet, 1843–1845, Baetis rhodani Pictet, 1843–1845, Rhithrogena carpatoalpina Klonowska, Olechowska, Sartoriet & Weichselbaumer, 1987 and Habroleptoides confusa Sartori & Jacob, 1986) in a temperature stable cold spring stream at Prosiek valley (Cho?ské vrchy Mts., West Carpathians, Slovakia). We have found asynchronous bivoltine life cycle for the most abundant species B. alpinus with growth rate positively correlated to photoperiod length. R. carpatoalpina have shown unusual asynchronous univoltine life cycle and B. rhodani have shown uncommonly low abundance in mayfly community. Total secondary production of mayfly community was very low, reaching 1654.8 mg DW m^?2 y^?1. We suggest that the observed asynchrony in growth could be related to the lack of temperature control.  相似文献