Pipe laying simulation with an active reel drive

Dynamic and quasi-static models for analysis of a pipe lay spread are presented in the paper. Depending on the type of a pipe, spooling it on a big drum (reel) may cause plastic deformations. When the pipe is reeled out at sea, again it undergoes plastic deformations. In order to model such a nonlinear behaviour, a model, which includes both elasto-plastic material characteristics and large deformations, is required. Discretisation of the pipe is performed by means of the Rigid Finite Element Method (RFEM), which allows us to study static and dynamic problems, taking into account required properties of the model. Different sea conditions are simulated and analysed. It is shown how operational conditions can limit the ability of laying operation by a dedicated vessel, due to an unstable system response. The second part of the paper presents an upgrade of a passive reel drive by application of an active drive. In the model used for control applications, the pipe is modelled by a neural network. This allows us to perform a real-time calculations. In this fast-response calculation model, nonlinear aspects of the system are taken into account. The improvements in a pipe laying vessel performance are presented by some results of numerical simulations. The conclusions are also formulated.     

Open-system chemical behavior in deep Wilcox Group mudstones,Texas Gulf Coast,USA

Wilcox Group mudstones have been mechanically and geochemically transformed over a temperature range of 20–200 °C. Our research controlled for provenance and age by sampling from five wells, parallel to the paleodepositional axis, all within the Houston delta system. Across the sampled depths, mudstone porosity has been reduced from ∼25 to <10% and bulk mineralogical change as documented by quantitative X-ray diffraction includes decreases in quartz, K-feldspar and kaolinite content whereas illite + illite − smectite, chlorite, and plagioclase increase. These mineral transformations transfer elements at a scale of less than 1 mm from one mineralogical form to another, however, X-ray fluorescence data suggest that among major elements only Al₂O₃ and TiO₂ are fully conserved within the system (trace-element ZrO₂ is also conserved). K₂O has been added to and SiO₂ released from the Wilcox Group mudstones. Cathodoluminescence and secondary electron imaging did not find this SiO₂ locally precipitated. We, therefore, document an open-system geochemical behavior.     

Centralization in the global avoided deforestation collaboration network

Reducing Emissions from Deforestation and Forest Degradation projects currently cover an area approximately twice the size of Germany and challenge traditional concepts of centralization and decentralization in studies of environmental governance. Emerging from the interactions of a complex network of actors, Reducing Emissions from Deforestation and Forest Degradation demonstrates that transnational governance networks of organizations can become spatially centralized. Using a historical analysis of the development of Reducing Emissions from Deforestation and Forest Degradation, we argue that the evolution of Reducing Emissions from Deforestation and Forest Degradation policy has been directed primarily from donor countries, especially in North America and Europe. Adopting a social network analysis approach, we present findings from a new dataset of collaboration on 276 Reducing Emissions from Deforestation and Degradation, avoided deforestation, and sustainable forest management projects that began some on-the-ground operations between 1989 and June 2012, finding that organizations in donor countries have from the beginning been the central actors in the Reducing Emissions from Deforestation and Forest Degradation network. We conclude that Reducing Emissions from Deforestation and Forest Degradation exhibits spatial centralization within transnational governance architectures despite institutional fragmentation, raising important normative questions about participation in transnational forest governance.     

Earth pillar formation on the Mountain Pine Ridge,Belize

The roadcuts of Belize's Mountain Pine Ridge feature numerous coarsely textured earth pillars less than 10 cm in height. Preferential impregnation of iron occurs over a buried pebble resulting in a dripline. The higher concentration of iron along the buried pebble's dripline is later oxidized and exposed to the surface by rainsplash erosion. For slopes greater than five degrees, the intensity of sheetwash erosion is great enough to remove pillars. Earth pillar genesis thus seems a function of laterization, slope angle, and sheetwash intensity.     

VLBI单基线解算地球自转参数的秩亏性证明

本文由VLBI延迟观测的基本方程出发,证明了VLBI单基线观测解算地球自转参数时存在的秩亏性。     

论自动化和智能化空间对地观测数据处理系统的建立

未来１０年遥感对地观测技术的发展使得遥感影像的获取将走向多种传感器、多分辨率、多谱段和多时相。各国计划发射的对地观测卫星将使我们能够同时获取大量的、不同分辨率的、多谱段的可见光、红外、微波辐射和侧视雷达的数据。从而构成用于全球变化研究、环境监测、资源调查、灾害防治的多层次遥感影像金字塔。为了能够及时地、充分地利用这些对地观测数据来回答地学研究和人类社会发展所面临时的问题，更好地发挥遥感为国民经济建设服务的巨大潜力，必须从技术上建立一个自动化和智能化的空间对地观测数据处理系统。鉴于目前应用滞后于发射，软件落后于硬件的现实情况，本文简要叙述建立自动化和智能化空间对地观测数据处理系统的必要性和可能性，分析建立该系统的主要目标和需解决的关键技术并希望国家集中各有关方面的人力和财力来共同攻关，以建立和完善我国的地球科学信息系统，提高综合研究与深入分析的现代化水平。     

西秦岭北缘断裂带新活动特征

在本文中，作者在近几年进行的大比例尺活断层地质填图工作的基础上，介绍了西秦岭北缘断裂带晚第四纪以来活动的基本待征，研究了该断裂带的空间展布情况、几何学和运动学特征、断层活动速率、古地震与地震重复周期等。结果表明，该断裂带自第四纪以来由压性逐渐演变为左旋扭动，其水平滑动速率为２．１－２．８ｍｍ／年，垂直滑动速率为０．４－０．７ｍｍ／年，地震复发周期约为５０００年。     

地幔流体与成矿作用

地球内部流体的活动乃是形成各种矿床的必要条件，是导致矿物聚积和金属成矿作用的前提。随着地球科学的进展，作为地球内部流体的重要组成部分，地幔流体越来越多的重视。本文在解剖世界首例白云鄂博地幔流体交代稀土矿床的基础上，初步总结了地幔流体与成矿作用的基本问题。     

北京重力地球潮参数和重力仪力学特性的测定

根据北京白家疃测站８台ＧＥＯ潮汐重力仪对比观测的资料，采用标准线性体流变模型模拟重力仪及记录系统的力学特性，计算各台仪器的格值改正系数、主潮汐波的振幅衰减系数和相位滞后；确定北京重力地球潮的振幅因子δ和相让滞后为δ（Ｍ_２）＝１．１７８４，δ（Ｏ_１）＝１．１８０４，δ（Ｍ_２）／δ（Ｏ_１）＝０．９９８３，（Ｍ_２）＝０．０７°，（Ｏ_１）＝０．１０°．     

环太平洋地震带与柯里奥利力

柯里奥利力是地球自转的一种惯性力，它使垂直下降的物体向东偏转，垂直上升的物体向西偏转，是形成环太平洋地震带中东西两岸构造应力差别的根本原因。