Characteristics of Deformation and Strength of Concrete in Plane Strain State

- The characteristics of deformation and strength of concrete under the plane strain condition are studied experimentally with the triaxial apparatus designed by the authors and are compared with those under the plane stress condition. A formula of stress transformation between plane stress and plane strain conditions is proposed for the elasto-plastic state, and it provides a theoretical basis for simplifying nonlinear analysis and fully using the strength of concrete.     

Development of a Vector-Based Method for Coastal Bluffline Mapping Using LiDAR Data and a Comparison Study in the Area of Lake Erie

This paper introduces a new method for bluffline extraction based on analysis of surface normal vectors derived from a 2.5-dimensional Delaunay triangulation network generated using a set of LiDAR points. The developed method has been implemented and tested for the extraction of blufflines in a section of the Lake Erie coastline near Painesville, Ohio. Comparison of the research results with those generated by a method for bluffline extraction based on slope information along elevation profiles on transects shows an improvement in both horizontal and vertical accuracies in situations where the bluff has a relatively sharp edge formation.     

底栖生物生产力现场测试系统(BCSPM)的建立及其初步实验结果

为对生态系统的健康评估及底栖生物资源的开发利用提供技术支撑,在胶州湾筏式养殖水域,建立了底栖生物生产力现场测试系统(BCSPM),并在光照和黑暗条件下测定了沉积物海水界面溶解氧随时间的变化、计算了氧通量、估算了底栖总初级生产力和群落呼吸。在光照较强的中午时刻测定的群落总生产力为20．76mgCm^-2h^-1;养殖水域沉积物中的群落呼吸要高于邻近水域。BCSPM整体运转良好,初步结果为系统的改进和进一步实验提供了依据。     

我国海域天然气水合物资源的地理信息系统建设方法与实践

目前对我国海域矿产资源所建立的地理信息系统主要以石油及天然气资源为研究对象。天然气水合物是一种全新的能源,与石油及天然气资源相比,无论是其在地下的赋存状况、成藏特征及其主要控制因素,还是储集空间的物化性质、资源富集的区域位置及深度、勘探开发方式等都有着显著差异,其数据库结构、相应数据项及数据格式与油气数据库不同,许多数据项尚缺乏统一的标准,其标准化工作尚需进一步探讨。以我国天然气水合物资源调查及评价有关数据为研究对象,对其数据项的标准化及天然气水合物资源地理信息系统的建设方法进行探讨,为国家将来制定相应的标准提供有用信息。     

Calibration of LRFD Format for Steel Jacket Offshore Platforms in China Offshore Area （ 1 ） ： Statistical Parameters of Loads and Resistances

1 .IntroductionThe structural design method has evolvedfromthe workingstress method,damage stage methodtolimit state method.The more recent probabilisticlimit state design method,whichis based onreliabili-tytheory,has beengenerallyacceptedinthe designcode…     

Calibration of LRFD Format for Steel Jacket Offshore Platform in China Offshore Area （2） ： Load, Resistance and Load Combination Factors

1.IntroductionLoad and Resistance Factor Design(LRFD)isthe commonly adoptedreliability-based designfor-mat for structural design(CNE,1990;AAHTO,1994;OMTC,1983;CMC,1984).Code calibra-tionforthe LRFDformat is a processto determinethetarget reliability by de…     

Long‐term comparison of structure and dynamics of the red coral metapopulation of the Portofino Promontory (Ligurian Sea): a case‐study for a Marine Protected Area in the Mediterranean Sea

A large amount of data on the precious coral Corallium rubrum has attested to a dramatic shift in the size structure of its over‐harvested Mediterranean populations in recent decades. One of the main problems for the conservation of this species is the substantial lack of data concerning the time span necessary for a population subjected to pluri‐decennial harvesting pressure to return to its pristine status. Here, we present a multi‐annual data set gathered from the Marine Protected Area (MPA) of Portofino, which hosts the most important shallow‐water coral populations in the Ligurian Sea and was subjected to strong harvesting pressure from the 1950s to the early 1970s. Quantitative comparison of the population structure data recorded in 1964, 1990 and 2012 indicated a strong size increase of the colonies (from 3 to 8 g mean weight), resulting in an increase in colony biomass from 300 to the current 1500 g·m^?2. As a consequence, over the same span of time, the density of colonies has slightly decreased. The role of mass mortality phenomena, like that occurred in this area during 1999, as possible biological features triggering the switch of red coral populations from a ‘grass plain‐like’ towards a ‘forest‐like’ structure, is discussed. All these data indicate that the instigation of MPAs is a winning strategy in the conservation of this precious species and similar management plans should also be evaluated for the protection of the deep benthic communities thriving on off‐shore banks.     

Stable carbon isotopic ratios of CH4-CO2-bearing fluid inclusions in fracture-fill mineralization from the Lower Saxony Basin (Germany) - A tool for tracing gas sources and maturity

The stable carbon isotopic ratios (δ¹³C) of methane (CH₄) and carbon dioxide (CO₂) of gas-rich fluid inclusions hosted in fracture-fill mineralization from the southern part of the Lower Saxony Basin, Germany have been measured online using a crushing device interfaced to an isotopic ratio mass spectrometer (IRMS). The data reveal that CH₄ trapped in inclusions seems to be derived from different source rocks with different organic matter types. The δ¹³C values of CH₄ in inclusions in quartz hosted by Carboniferous rocks range between −25 and −19‰, suggesting high-maturity coals as the source of methane. Methane in fluid inclusions in minerals hosted by Mesozoic strata has more negative carbon isotope ratios (−45 to −31‰) and appears to represent primary cracking products from type II kerogens, i.e., marine shales. There is a positive correlation between increasing homogenization temperatures of aqueous fluid inclusions and less negative δ¹³C(CH₄) values of in co-genetic gas inclusions probably indicating different mtaturity of the potential source rocks at the time the fluids were released. The CO₂ isotopic composition of CH₄-CO₂-bearing inclusions shows slight negative or even positive δ¹³C values indicating an inorganic source (e.g., water-rock interaction and dissolution of detrital, marine calcite) for CO₂ in inclusions. We conclude that the δ¹³C isotopic ratios of CH₄-CO₂-bearing fluid inclusions can be used to trace migration pathways, sources of gases, and alteration processes. Furthermore, the δ¹³C values of methane can be used to estimate the maturity of the rocks from which it was sourced. Results presented here are further supported by organic geochemical analysis of surface bitumens which coexist with the gas inclusion-rich fracture-fill mineralization and confirm the isotopic interpretations with respect to fluid source, type and maturity.