Optimization of slope angle and its seismic stability: A case study for the proposed open pit coalmine in Phulbari, NW Bangladesh

The present study reflects upon the results of substantial program of two-dimensional Finite Element Method （FEM） numerical analyses of the open pit that links to slope angle optimization associated with the safety factor of the pit slope of a coal mine in Bangladesh. In the present analyses, two types of models have been presented. The first model estimates safety factor without seismic effect on the overall pit slope of the model; the second model incorporates safety factor with seismic stability of the model. The calculated optimum slope angle of the first model is 31% with a rational safety factor of 1.51, prior to the seismic effect. However, the value is reduced to 0.93, 0.82, and 0.72, after we applies the seismic effect in the second model with M6, M6.5, and M7, respectively. Finally, our modeling results emphasize that for the case of the proposed Phulbari coalmine, there is extremely high prospect for causing massive slope failure along the optimum pit slope angle with 31% if the mine area felt seismic shaking, like the Sikkim （in northern India） earthquake with M6.9 on September 18, 2011.     

Assembly and concept of a web-based GIS within the paleolimnological project CONTINENT (Lake Baikal,Russia)

Web-based Geographical Information Systems (GIS) are excellent tools within interdisciplinary and multi-national geoscience projects to exchange and visualize project data. The web-based GIS presented in this paper was designed for the paleolimnological project ‘High-resolution CONTINENTal paleoclimate record in Lake Baikal’ (CONTINENT) (Lake Baikal, Siberia, Russia) to allow the interactive handling of spatial data. The GIS database combines project data (core positions, sample positions, thematic maps) with auxiliary spatial data sets that were downloaded from freely available data sources on the world wide web. The reliability of the external data was evaluated and suitable new spatial datasets were processed according to the scientific questions of the project. GIS analysis of the data was used to assist studies on sediment provenance in Lake Baikal, or to help answer questions such as whether the visualization of present-day vegetation distribution and pollen distribution supports the conclusions derived from palynological analyses. The refined geodata are returned back to the scientific community by using online data publication portals. Data were made citeable by assigning persistent identifiers (DOI) and were published through the German National Library for Science and Technology (TIB Hannover, Hannover, Germany).     

The role of silica in the hydrous metamorphism of chromite

Retrograde hydrous metamorphism has produced three types of microstructures in chromite grains from chromitites and enclosing rocks of the Tapo Ultramafic Massif (Central Peruvian Andes). In semi-massive chromitites (60–80 vol% chromite), (i) partly altered chromite with homogeneous cores surrounded by lower Al₂O₃ and MgO but higher Cr₂O₃ and FeO porous chromite with chlorite filling the pores. In serpentinites (ii) zoned chromite with homogeneous cores surrounded by extremely higher Fe₂O₃ non-porous chromite and magnetite rims, and (iii) non-porous chromite grains. The different patterns of zoning in chromite grains are the consequences of the infiltration of reducing and SiO₂-rich fluids and the subsequent heterogeneous interaction with more oxidizing and Fe-bearing fluids. During the first stage of alteration under reduced conditions magmatic chromite is dissolved meanwhile new metamorphogenic porous chromite crystallizes in equilibrium with chlorite. This reaction that involves dissolution and precipitation of minerals is here modeled thermodynamically for the first time. µSiO₂-µMgO pseudosection calculated for unaltered semi-massive chromitites at 2 kbar and 300 °C, the lowest P-T conditions inferred from the Tapo Ultramafic Massif and Marañón Complex, predicts that chromite + chlorite (i.e., partly altered chromite) is stable instead of chromite + chlorite + brucite at progressive higher µSiO₂ but lower µMgO. Our observation is twofold as it reveals that the important role of SiO₂ and MgO and the open-nature of this process. P-T-X diagrams computed using the different P-T pathways estimated for the enclosing Tapo Ultramafic Massif reproduce well the partial equilibrium sequence of mineral assemblages preserved in the chromitites. Nevertheless, it is restricted only to the P-T conditions of the metamorphic peak and that of the latest overprint. Our estimations reveal that a high fluid/rock ratio (1:40 ratio) is required to produce the microstructures and compositional changes observed in the chromitites from the Tapo Ultramafic Massif. The circulation of SiO₂-rich fluids and the mobilization of MgO from the chromitite bodies are linked with the formation of garnet amphibolites and carbonate-silica hydrothermalites (i.e., listwaenites and birbirites) in the ultramafic massif. The origin of these fluids is interpreted as a result of the dissolution of orthopyroxene and/or olivine from the metaharzburgites and metagabbros enclosed in the Tapo Ultramafic Massif.     

Developing geographic information infrastructures: the role of access policies

Within societies, information availability is a key issue affecting society's well‐being. For geographic information, a geographic information infrastructure (GII) facilitates availability and access to geographic information for all levels of government, the commercial sector, the non‐profit sector, academia, and ordinary citizens. Although the importance of access policies in the development of a GII is commonly understood, research that has assessed the impact of access policies on this development is scant. This article adds this perspective. Based on information acquired from case‐study and literature research, the author argues that open‐access policies do not always promote GII development and in specific instances are counter‐productive. These findings may explain why many nations still adhere to cost‐recovery policies instead of following access policies recommended by research. The article provides alternatives for changing current policies into new access policies that promote GII development.     

Turbulence characteristics of flows passing through a tetrahedron frame in a smooth open-channel

The turbulence characteristics of flows passing through a tetrahedron frame were investigated by using a 2-dimensional fiber-optic laser Doppler velocimeter (2-D FLDV). Experiments for uniform flows with different bed slopes under both submerged and un-submerged conditions were carried out in a re-circulating flume with glass side walls. The experimental bed was a smooth fixed bed. It was observed that with the tetrahedron frame the mean longitudinal velocity decrease in the retardation zone. However, both the longitudinal and the vertical turbulence intensities are larger than those for the undisturbed approach flow. The tetrahedron frame may reduce the probability of sediment entrainment by retarding the flow and reducing the boundary shear stress. In addition, it may induce sediment deposition in a sediment laden flow by changing the flow direction and increasing the energy dissipation.     

DuMu: DUNE for multi-{phase, component, scale, physics, …} flow and transport in porous media

DuMu^x is a free and open-source simulator for flow and transport processes in porous media, based on the Distributed and Unified Numerics Environment (DUNE). Its main intention is to provide a sustainable and consistent framework for the implementation and application of model concepts, constitutive relations, discretizations, and solvers. The paper provides an overview of DuMu^x with the focus on software-related aspects. Selected examples highlight the multi-scale and the parallel capabilities.     

浅谈新疆测震台网传输链路的改造

要做到IP到台站有很多种方式可选,根据新疆测震台网各台站的现状列举了7类不同的数据传输方式,这些数据传输方式在新疆测震台网中均得到应用,也都达到IP到台站的目的.分别对这些数据传输链路的原理及优缺点进行阐述,并结合目前各台站具体情况作链路适用性的相关分析,希望能够对其他省局台网的台站通信链路设计、改造起到参考.     

Coupled discrete element and finite volume solution of two classical soil mechanics problems

One dimensional solutions for the classic critical upward seepage gradient/quick condition and the time rate of consolidation problems are obtained using coupled routines for the finite volume method (FVM) and discrete element method (DEM), and the results compared with the analytical solutions. The two phase flow in a system composed of fluid and solid is simulated with the fluid phase modeled by solving the averaged Navier–Stokes equation using the FVM and the solid phase is modeled using the DEM. A framework is described for the coupling of two open source computer codes: YADE-OpenDEM for the discrete element method and OpenFOAM for the computational fluid dynamics. The particle–fluid interaction is quantified using a semi-empirical relationship proposed by Ergun [12]. The two classical verification problems are used to explore issues encountered when using coupled flow DEM codes, namely, the appropriate time step size for both the fluid and mechanical solution processes, the choice of the viscous damping coefficient, and the number of solid particles per finite fluid volume.     

More than just access to fish: The pros and cons of fisher participation in a customary marine tenure (Padu) system under pressure

The Padu system of South Asia has received growing attention as an example of customary marine tenure that has survived despite rapid development and change throughout the region’s fisheries. This paper describes the Padu system as it functions at Pulicat lagoon, India, where it has enjoyed decades of legitimacy amongst its members, and has contributed to sustainable fishing. Recently, however, the Padu system has become unstable, driven by pressures of an expanding fishing population, reduced access to fishing grounds and a growing ‘shared poverty’. In spite of this, fisher loyalty to uphold the Padu system remains strong. This raises questions about the broader social, political and cultural meanings of Padu, which extend beyond access to a lucrative fishery. The paper highlights a trade-off between the benefits received through Padu membership at a societal level through collective action, and the individual costs of partaking in ‘shared poverty’, which is inherently distributed unequally amongst fishing families. The paper concludes with a discussion on the future of the Padu system in Pulicat, drawing from evolutionary pathways of other Padu systems in the region. It is suggested that, in the Pulicat case, the high social values attributed to the Padu system, alongside complex power structures, may hinder institutional adaptation.     

加拿大海王星:科学、运行、管理

加拿大海王星是世界最大的海底缆接科学观测网,于2009年开始运行.它连接了位于不同水深和不同海洋地质环境的大批观测仪器,把数据连续不断地通过互联网传给科学家和大众.海王星的建立是为了推动地震过程和大地构造、海底地下流体、海洋生物与气候变化、深海生态系统、工程和信息科学等五大科学命题的研究.为最大程度地推动国际合作,加速科学发展步伐,它的系统使用完全开放,数据全部免费公开,这在科学史上前所未见.这种全方位、全开放的复杂庞大的科研系统需要高超的管理方法和优良的学术环境.